5+3)/2 »</font\n> 2.618\\sqrt{5}+3)/2 \\approx 2.618. (ii) The matching upper bound is achieved by a relatively simple online algorithm if repacking is allowed. (iii) Without\n repacking, we can achieve an upper bound of 3 by using the concept of bricks by Januszewski and Lassak [11]. (iv) The offline version of the problem admits a PTAS.","Title: Online multiple-strip packing\nYear: 2011\n\nAbstract: We study an online multiple-strip packing problem, whose goal is to pack the given rectangles into m vertical strips of unit width such that the maximum height used among the strips is minimized. Rectangles arrive one by one. The decision of delivering the rectangles to a strip as well as packing them into the strip must be done immediately and irrevocably without any information on the next rectangles. Both randomized and deterministic online algorithms are investigated, all of which are guaranteed a constant competitive ratio.","Title: Strategy-proof approximation mechanisms for an obnoxious facility game on networks\nYear: 2013\n\nAbstract: We study a new facility game, namely, an obnoxious facility game, on a network where the facility is undesirable and all agents try to be as far away from the facility as possible. The following process is considered: at first the agents declare their locations, then, given these bids, a mechanism selects a place on the network to locate the facility. The aim of the mechanism is to maximize the obnoxious social welfare, i.e., the total distance between the agents and the facility. The objective of each agent is to maximize his/her utility, i.e., the distance from the facility. Thus an agent may lie if, by doing so, he/she can get strictly more benefit. We are interested in mechanisms without money to decide the facility location so that the obnoxious social welfare is maximized and all agents are enforced to report their true locations. In this paper we give a first attempt at this game on different networks. Our main results are the following. When the network is a path, we show a 3-approximation group strategy-proof deterministic mechanism which is best possible if the facility can only take one of the endpoints on the path, and a group strategy-proof randomized mechanism with tight approximation ratio of 32. When the networks are a circle (known as a ring in the case of computer networks) and a tree, we propose two group strategy-proof deterministic mechanisms that each provides the approximation ratio of 3. Furthermore, when all agents are on a general network, we propose a 4-approximation group strategy-proof deterministic mechanism and a 2-approximation group strategy-proof randomized mechanism.","Title: A new approximation algorithm for UET-Scheduling with chain-type precedence constraints\nYear: 1998\n\nAbstract: Jansen et al. [Jansen, K., Woeginger, G. J. and Yu, Z., UET-Scheduling with chain-type precedence constraints . Report 277, Technische Universität Graz, Institut für Mathematik, Graz, Austria, 1993.] studied the U2Chain problem in which two processors are given and all jobs have unit processing time; every job can be executed on only one machine; there are chain-type precedence constraints among the jobs and the objective is to minimize the makespan. This problem arises from the job-system where different jobs require different resources, thus a job may be processed only on some special machine. Since the problem is strongly NP-hard, they gave an approximation algorithm with performance ratio of 5/3. The purpose of our paper is to improve their result by giving a new approximation algorithm with a worst-case guarantee 3/2 for this problem. In this paper a new approximation algorithm with worst case performance ratio 3/2 is presented for the problem of scheduling unit execution time jobs on two parallel machines with the objective of minimizing the makespan where each job can be processed on only one machine and there are chain-type precedence constraints in the jobs. This result answers an open problem in Jansen et al. [Jansen, K., Woeginger, G. J. and Yu, Z., UET-Scheduling with chain-type precedence constraints . Report 277, Technische Universität Graz, Institut für Mathematik, Graz, Austria, 1993.]: “Does there exist a polynomial time heuristic with worst-case guarantee better than 5/3 for the problem U2Chain?”. The new approximation algorithm is also applied to the problem J 2| pmtn | C max .","Title: Single machine batch scheduling to minimize the sum of total flow time and batch delivery cost with an unavailability interval.\nYear: 2014\n\nAbstract: This paper addresses the problem of scheduling n nonresumable and simultaneously available jobs on a single machine, where the machine has a fixed unavailability interval, and the jobs are delivered in batches to the customers. There is no capacity limit on each delivery batch, and the cost per batch delivery is fixed and independent of the number of jobs in the batch. The goal is to find the optimal delivery date for each job and an optimal job sequence to minimize the sum of total flow time and batch delivery cost. The problem is shown to be NP-hard based on a reduction from the Equal-Size Partition Problem. Then a pseudo-polynomial time algorithm is developed, establishing that it is NP-hard in the ordinary sense. Finally, by applying the interval partitioning technique and the rounding technique, a fully polynomial time approximation scheme (FPTAS) and a bicriteria fully polynomial time approximation scheme are developed, which run in time On5ε2+n5logn and On6ε, respectively.","Title: Scheduling with a minimum number of machines\nYear: 2009\n\nAbstract: We investigate the scheduling problem with release dates and deadlines on a minimum number of machines. In the case of equal release dates, we present a 2-approximation algorithm. We also show that Greedy Best-Fit (GBF) is a 6-approximation algorithm for the case of equal processing times.","Title: On the optimality of approximation schemes for the classical scheduling problem\nYear: 2013\n\nAbstract: We consider the classical scheduling problem on parallel identical machines to minimize the makespan. There is a long history of studies on this problem, focusing on exact and approximation algorithms, and it is thus natural to consider whether these algorithms are best possible in terms of the running time. Under the Exponential Time Hypothesis (ETH), we achieve the following results in this paper: • The scheduling problem on a constant number m of identical machines, which is denoted as Pm||Cmax, is known to admit a fully polynomial time approximation scheme (FPTAS) of running time O(n) + (1/ε)O(m) (indeed, the algorithm works for an even more general problem where machines are unrelated). We prove this algorithm is essentially the best possible in the sense that a (1/ε)O(m1-δ) + nO(1) time FPTAS for any δ > 0 implies that ETH fails. • The scheduling problem on an arbitrary number of identical machines, which is denoted as P||Cmax, is known to admit a polynomial time approximation scheme (PTAS) of running time 2O(1/ε2 log3(1/ε))+nO(1). We prove this algorithm is nearly optimal in the sense that a 2O((1/ε)1-δ+nO(1) time PTAS for any δ > 0 implies that ETH fails, leaving a small room for improvement. In addition, we also consider exact algorithms for the scheduling problem and prove the following result: • The traditional dynamic programming algorithm for P||Cmax is known to run in 2O(n) time. We prove this is essentially the best possible in the sense that even if we restrict that there are n jobs and the processing time of each job is bounded by O(n), an exact algorithm of running time 22O(n1-δ) for any δ > 0 implies that ETH fails. To obtain these results we will provide two new reductions from 3SAT, one for Pm||Cmax and another for P||Cmax. Indeed, the new reductions explore the structure of scheduling problems and can also lead to other interesting results. For example, using the framework of our reduction for P||Cmax, Chen et al. [5] are able to prove the APX-hardness of the scheduling problem in which the matrix of job processing times P = (pij)mxn is of rank 3, solving the open problem mentioned in [2].","Title: Online Scheduling on a CPU-GPU Cluster.\nYear: 2013\n\nAbstract: We consider the online scheduling problem in a CPU-GPU cluster. In this problem there are two sets of processors, the CPU processors and GPU processors. Each job has two distinct processing times, one for the CPU processor and the other for the GPU processor. Once a job is released, a decision should be made immediately about which processor it should be assigned to. The goal is to minimize the makespan, i.e., the largest completion time among all the processors. Such a problem could be seen as an intermediate model between the scheduling problem on identical machines and unrelated machines. We provide a 3.85-competitive online algorithm for this problem and show that no online algorithm exists with competitive ratio strictly less than 2. We also consider two special cases of this problem, the balanced case where the number of CPU processors equals to that of GPU processors, and the one-sided case where there is only one CPU or GPU processor. We provide a (1 + v3)-competitive algorithm for the balanced case, and a 3-competitive algorithm for the one-sided case. © Springer-Verlag Berlin Heidelberg 2013.","Title: On-line scheduling of parallel jobs on two machines\nYear: 2008\n\nAbstract: We study the problem of on-line scheduling of parallel jobs on two machines. The jobs are parallel in the sense that each of them specifies the number of processors, in this case 1 or 2, required for simultaneous processing. The jobs are presented one by one. Upon receiving a job, we must assign the job to a time slot in the schedule before the next job is presented. No re-assignment is allowed. The goal is to minimize the makespan of the final schedule. There is a straightforward algorithm which achieves a competitive ratio of 2. In this paper we show that no on-line algorithm can have a competitive ratio less than 1+2/3(~1.816). We also study two special cases of the problem: (i) Jobs arrive in a non-decreasing order of processing times where we give an optimal algorithm with competitive ratio 3/2; (ii) Jobs arrive in a non-increasing order of processing times where we show that no on-line algorithm has a competitive ratio less than 9/7 and give a greedy algorithm with a competitive ratio 4/3.","Title: On-line scheduling of parallel jobs in a list\nYear: 2007\n\nAbstract: We study an on-line parallel job scheduling problem, where jobs arrive one by one. A parallel job may require a number of machines for its processing at the same time. Upon arrival of a job, its processing time and the number of requested machines become known, and it must be scheduled immediately without any knowledge of future jobs. We present a 7-competitive on-line algorithm, which improves the previous upper bound of 12 by Johannes (J. Sched. 9:433---452, 2006). Furthermore, we investigate a special case in which the largest processing time is known beforehand.","Title: A Note on Online Scheduling for Jobs with Arbitrary Release Times\nYear: 2009\n\nAbstract: We investigate the problem of on-line scheduling for jobs with arbitrary release times on m identical parallel machines. The goal is to minimize the makespan. We derive a best possible online algorithm with competitive ratio of 2 for m = 2. For a special case that all the jobs have unit processing times, we prove that Algorithm LS has a tight bound of 3/2 for general m machines.","Title: A constrained minimum spanning tree problem\nYear: 2000\n\nAbstract: In this paper, we give an O(n(2)) algorithm for finding a point on a given line I which, if added to a given set of n points located on one side of l, will result in the minimum spanning tree.","Title: Mechanisms for obnoxious facility game on a path\nYear: 2011\n\nAbstract: We consider a new facility game, namely, an obnoxious facility game where the facility is undesirable and all agents try to be as far away from the facility as possible. The social cost is the total distance between the agents and the facility. However, an obnoxious facility is placed based on the reported locations of the selfish agents. We are interested in a mechanism to decide the facility location so that the social cost is maximized. In this paper, we give a first attempt for this game on a path. Our main results include a 3-approximation group strategy-proof deterministic mechanism, which is best possible if the facility can only take one of the endpoints on the path, and two group strategy-proof randomized mechanisms with approximation ratio of 5/3 and 3/2, respectively","Title: Harmonic algorithm for 3-dimensional strip packing problem\nYear: 2007\n\nAbstract: In the three dimensional strip packing problem, we are given a set of three-dimensional rectangular items I = {(xi, yi, zi) : i = 1, ..., n} and a three dimensional box B. The goal is to pack all the items in the box B without any overlap, such that the height of the packing is minimized. We consider the most basic version of the problem, where the items must be packed with their edges parallel to the edges of B and cannot be rotated. Building upon Caprara's work [4] for the two dimensional bin packing problem we obtain an approximation algorithm with a similar performance guarantee of T∞ ≈ 1.69 where T∞ is the well known Harmonic number that occurs naturally in the context of bin packing. The previously known approximation algorithms for this problem had worst case performance guarantees of 2 [7], 2.64 [14], 2.67 [15], 2.89 [10] and 3.25 [11]. Our second algorithm is an asymptotic PTAS for the case in which all items have square bases.","Title: Maximizing the Number of Packed Rectangles\nYear: 2004\n\nAbstract: Given a set of rectangles we are asked to pack as many of them as possible into a bigger rectangle. The rectangles packed may not overlap and may not be rotated. This problem is NP-hard in the strong sense even for packing squares into a square. We establish the relationship between the asymptotic worst-case ratio and the (absolute) worst-case ratio for the problem. It is proved that there exists an asymptotic FPTAS, and thus a PTAS, for packing squares into a rectangle. We give an approximation algorithm with asymptotic ratio of at most two for packing rectangles, and further show a simple (2 + epsilon)-approximation algorithm.","Title: On-line scheduling mesh jobs with dependencies\nYear: 2007\n\nAbstract: We study an on-line problem of scheduling parallel jobs on two-dimensional meshes. Parallel jobs arrive dynamically according to the dependencies between them, which are unknown before the jobs appear. Each job may need more than one processor simultaneously and is required to be scheduled on a submesh of the processors which are located on a two-dimensional mesh, i.e., a job must be scheduled on a rectangle of given dimensions. The objective is to minimize the maximum completion time (makespan). We deal with a UET job system, in which all job processing times are equal. We show a lower bound of 3.859 and present a 5.25-competitive algorithm. It significantly improves a previous lower bound of 3.25 and a previous upper bound of 46/7. We consider also the rotated two-dimensional mesh, in which the parallel jobs can be rotated and the rotation of all the jobs is feasible. A lower bound of 3.535 is proven and an on-line algorithm with competitive ratio of at most 4.25 is derived.","Title: Common deadline lazy bureaucrat scheduling revisited\nYear: 2006\n\nAbstract: Lazy bureaucrat scheduling is a new class of scheduling problems introduced by Arkin et al. [1]. In this paper we focus on the case where all the jobs share a common deadline. Such a problem is denoted as CD-LBSP, which has been considered by Esfahbod et al. [2]. We first show that the worst-case ratio of the algorithm SJF (Shortest Job First) is two under the objective function [min-time-spent], and thus answer an open question posed in [2]. We further present two approximation schemes Ak and Bk both having worst-case ratio of $\\frac{k+1}{k}$, for any given integer k0, under the objective function [min-makespan] and [min-time-spent] respectively. Finally, we prove that the problem CD-LBSP remains NP-hard under several objective functions, even if all jobs share the same release time.","Title: Deterministic on-line call control in cellular networks\nYear: 2010\n\nAbstract: We study an on-line call control problem in cellular networks that are based on the Frequency Division Multiplexing (FDM) technology. In such networks, interference may occur when the same frequency is assigned to two different calls emanating from the same cell or its neighboring cells. The number of frequencies supporting the networks is limited. The goal is to maximize the number of calls served without causing any interference. We focus on the case that the number of frequencies is sufficiently large and the calls stay forever. We give a deterministic on-line algorithm with asymptotic competitive ratio of 2.5 and show a general lower bound of 2. For the special case of linear cellular networks, we achieve a best possible deterministic on-line algorithm with asymptotic competitive ratio of 3/2.","Title: Optimal on-line algorithms for variable-sized bin covering\nYear: 1999\n\nAbstract: We deal with the variable-sized bin covering problem: Given a list L of items in (0,1] and a finite collection B of feasible bin sizes, the goal is to select a set of bins with sizes in B and to cover them with the items in L such that the total size of the covered bins is maximized. In the on-line version of this problem, the items must be assigned to bins one by one without previewing future items. This note presents a complete solution to the on-line problem: For every collection B of bin sizes, we give an on-line approximation algorithm with a worst-case ratio r(B), and we prove that no on-line algorithm can perform better in the worst case. The value r(B) mainly depends on the largest gap between consecutive bin sizes.","Title: Linear time-approximation algorithms for bin packing\nYear: 2000\n\nAbstract: Simchi-Levi (Naval Res. Logist. 41 (1994) 579-585) proved that the famous bin packing algorithms FF and BF have an absolute worst-case ratio of no more than 74, and FFD and BFD have an absolute worst-case ratio of 32, respectively. These algorithms run in time O(nlogn). In this paper, we provide a linear time constant space (number of bins kept during the execution of the algorithm is constant) off-line approximation algorithms with absolute worst-case ratio 32. This result is best possible unless P=NP. Furthermore, we present a linear time constant space on-line algorithm and prove that the absolute worst-case ratio is 74.","Title: Maximizing the throughput of parallel jobs on hypercubes\nYear: 2007\n\nAbstract: We study a problem of scheduling n independent parallel jobs on hypercubes. A parallel job is required to be scheduled on a subcube of processors. All jobs are available at the beginning, each of which is associated with a due date. The objective is to maximize the total number of early jobs. We provide an optimal polynomial time algorithm for the unit processing time job system.","Title: New Upper Bounds on The Approximability of 3D Strip Packing\nYear: 2006\n\nAbstract: In this paper, we study the 3D strip packing problem in which we are given a list of 3- dimensional boxes and required to pack all of them into a 3-dimensional strip with length 1 and width 1 and unlimited height to minimize the height used. Our results are below: i) we give an approximation algorithm with asymptotic worst-case ratio 1.69103, which improves the previous best bound of 2 + ǫ by Jansen and Solis-Oba of SODA 2006; ii) we also present an asymptotic PTAS for the case in which all items have square bases.","Title: Bin Packing of Selfish Items\nYear: 2008\n\nAbstract: We study a bin packing game in which any item to be packed is handled by a selfish agent. Each agent aims at minimizing his sharing cost with the other items staying in the same bin, where the social cost is the number of bins used. We first show that computing a pure Nash equilibrium can be done in polynomial time. We then prove that the price of anarchy for the game is in between 1.6416 and 1.6575, improving the previous bounds.","Title: Hardness of lazy packing and covering\nYear: 2009\n\nAbstract: We prove APX-hardness for the two problems maximum resource bin packing and lazy bin covering. Simple algorithms matching the best absolute bounds under the assumption PNP are also derived.","Title: Online Scheduling of Parallel Jobs with Dependencies on 2-Dimensional Meshes\nYear: 2003\n\nAbstract: We study an on-line problem of scheduling parallel jobs on 2-dimensional meshes. Parallel jobs arrive dynamically according to the dependencies between them, which are unknown before the jobs appear. Each job may need more than one processor simultaneously and is required to be scheduled on a submesh of the processors which are located on a 2-dimensional mesh, i.e., a job must be scheduled on a rectangle of given dimensions. The objective is to minimize the maximum completion time (makespan). We deal with an UET job system, in which all job processing times are equal. We show a lower bound of 3.859 and present a 5.25-competitive algorithm. It significantly improves a previous lower bound of 3.25 and a previous upper bound of 46/7. We consider also the rotated 2-dimensional mesh, in which the parallel jobs can be rotated. A lower bound of 3.535 is proven and an on-line algorithm with competitive ratio of at most 4.25 is derived.","Title: Offline Scheduling of Multi-threaded Request Streams on a Caching Server\nYear: 2011\n\nAbstract: In this work, we are interested in the problem of satisfying multiple concurrent requests submitted to a computing server. Informally, there are users each sending a sequence of requests to the server. The requests consist of tasks linked by precedence constraints. Tasks may occur several times in the same sequence as well as in a request sequence of another user. The computing server has to execute tasks with variable processing times. The server owns a cache of limited size where intermediate results of the processing may be stored. If an intermediate result for a task is stored into the cache, no processing cost has to be paid and the result can directly be fetched from the cache. The goal of this work is to determine a schedule of the tasks such that an optimization function is minimized (the only objective studied up to now is the make span). This problem is a variant of caching which considers only one sequence of requests. We then extend the study to the minimization of the mean completion time of the request sequences. Two models are considered. In the first model, caching is forced whereas in the second model caching is optional and one can choose whether an intermediate result is stored in the cache or not. All combinations turn out to be NP-hard for fixed cache sizes and we provide a formulation as dynamic program as well as bounds for in approximation. We propose polynomial time approximation algorithms for some variants and analyze their approximation ratios. Finally, we also devise some heuristics and present experimental results. Tasks may occur several times in the same sequence as well as in a request sequence of another user. The computing server has to execute tasks with variable processing times. The server owns a cache of limited size where intermediate results of the processing may be stored. If an intermediate result for a task is stored into the cache, no processing cost has to be paid and the result can directly be fetched from the cache. The goal of this work is to determine a schedule of the tasks such that an optimization function is minimized (the only objective studied up to now is the make span). This problem is a variant of caching which considers only one sequence of requests. We then extend the study to the minimization of the mean completion time of the request sequences. Two models are considered. In the first model, caching is forced whereas in the second model caching is optional and one can choose whether an intermediate result is stored in the cache or not. All combinations turn out to be NP-hard for fixed cache sizes and we provide a formulation as dynamic program as well as bounds for in approximation. We propose polynomial time approximation algorithms for some variants and analyze their approximation ratios. Finally, we also devise some heuristics and present experimental results.","Title: A 3-approximation algorithm for two-dimensional bin packing\nYear: 2005\n\nAbstract: In the classical two-dimensional bin packing problem one is asked to pack a set of rectangular items, without overlap and without any rotation, into the minimum number of identical square bins. We give an approximation algorithm with absolute worst-case ratio of 3.","Title: Online knapsack with resource augmentation\nYear: 2010\n\nAbstract: It is known that online knapsack is not competitive. This negative result remains true even if items are removable. In this paper we consider online removable knapsack with resource augmentation, in which we hold a knapsack of capacity R=1 and aim at maintaining a feasible packing to maximize the total profit of items packed into the knapsack. Both scenarios that removal of accepted items is allowed and is not allowed are investigated. We evaluate an online algorithm by comparing the resulting packing to an optimal packing that uses a knapsack of capacity one. Optimal online algorithms are derived for both the weighted case (items have arbitrary profits) and the unweighted case (the profit of an item is equal to its size).","Title: On-Line Multiple-Strip Packing\nYear: 2009\n\nAbstract: We study the multiple-strip packing problem, in which the goal is to pack all the rectangles into m vertical strips of unit widths such that the maximum height among strips used is minimized. A number of on-line algorithms for this problem are proposed, in which the decision of delivering the rectangles to strips as well as packing the rectangles in strips must be done on-line. Both randomized and deterministic on-line algorithms are investigated, and all of them are guaranteed to have constant competitive ratios.","Title: A note on scheduling with low rank processing times.\nYear: 2013\n\nAbstract: We consider the classical minimum makespan scheduling problem, where the processing time of job $j$ on machine $i$ is $p_{ij}$, and the matrix $P=(p_{ij})_{m\\times n}$ is of a low rank. It is proved in (Bhaskara et al., SODA 2013) that rank 7 scheduling is NP-hard to approximate to a factor of $3/2-\\epsilon$, and rank 4 scheduling is APX-hard (NP-hard to approximate within a factor of $1.03-\\epsilon$). We improve this result by showing that rank 4 scheduling is already NP-hard to approximate within a factor of $3/2-\\epsilon$, and meanwhile rank 3 scheduling is APX-hard.","Title: On lazy bureaucrat scheduling with common deadlines\nYear: 2008\n\nAbstract: Lazy bureaucrat scheduling is a new class of scheduling problems introduced by Arkin et al. (Inf. Comput. 184:129–146, 2003). In this paper we focus on the case where all the jobs share a common deadline. Such a problem is denoted as CD-LBSP, which\n has been considered by Esfahbod et al. (Algorithms and data structures. Lecture notes in computer science, vol. 2748, pp. 59–66,\n 2003). We first show that the worst-case ratio of the algorithm SJF (Shortest Job First) is two under the objective function [min-time-spent], and thus answer an open question posed in (Esfahbod, et al. in Algorithms and data structures. Lecture notes in computer\n science, vol. 2748, pp. 59–66, 2003). We further present two approximation schemes A\n \n k\n and B\n \n k\n both having worst-case ratio of \n \n , for any given integer k>0, under the objective functions [min-makespan] and [min-time-spent], respectively. Finally, we prove that the problem CD-LBSP remains NP-hard under several objective functions, even if all\n jobs share the same release time.","Title: Optimal online-list batch scheduling\nYear: 2009\n\nAbstract: We consider the online-list batch scheduling problem. Jobs arrive one by one and have to be assigned upon arrival to a scheduled batch such that the makespan is minimized. Each batch can accommodate up to B jobs. We give a complete classification of the tractability of this online problem.","Title: A simple semi on-line algorithm for P2//Cmax with a buffer\nYear: 1997\n\nAbstract: In this paper, we investigate a semi on-line version of the parallel machine scheduling problem. We are given a buffer of length k which is available to maintain k jobs. The jobs arrive one by one and can be temporarily assigned to the buffer if the buffer is not full. The goal is to assign all jobs to the identical machines such that the makespan is minimized. For two machines, Kellerer et al. (1995) showed that no heuristic for this problem can have a worst-case ratio lower than 43. This paper presents a simple algorithm with worst-case ratio 43 for P2//Cmax with a buffer of length 1.","Title: On-line scheduling with extendable working time on a small number of machines\nYear: 2003\n\nAbstract: Speranza and Tuza [Ann. Oper. Res. 86 (1999) 494-506] studied the on-line problem of scheduling jobs on m identical machines with extendable working time. In this problem, each machine is assumed to have an identical regular working time, which can be extended if necessary. The working time of a machine is the larger one between its regular working time and the total processing time of jobs assigned to it. The objective is to minimize the total working time of machines. They presented an on-line algorithm Hx, with a competitive ratio at most 1.228 for any number of machines by choosing an appropriate parameter x. In this paper we consider a small number of machines. The best choices of x are given for m = 2, 3, 4 and the tight bounds, 7/6, 11/9 and 19/16, respectively, are proved. Among them, the algorithm for m = 2 is best possible. We then derive a new algorithm for m = 3 with a competitive ratio 7/6.","Title: On Two Dimensional Orthogonal Knapsack Problem\nYear: 2008\n\nAbstract: In this paper, we study the following knapsack problem: Given a list of squares with profits, we are requested to pack a sublist of them into a rectangular bin (not a unit square bin) to make profits in the bin as large as possible. We first observe there is a Polynomial Time Approximation Scheme (PTAS) for the problem of packing weighted squares into rectangular bins with large resources, then apply the PTAS to the problem of packing squares with profits into a rectangular bin and get a 6 5 + ǫ approximation algorithm.","Title: Online scheduling of equal-length jobs on parallel machines\nYear: 2007\n\nAbstract: We study on-line scheduling of equal-length jobs on parallel machines. Our main result is an algorithm with competitive ratio decreasing to e/(e - 1) ≅ 1.58 as the number of machine increases. For m ≥ 3, this is the first algorithm better than 2-competitive greedy algorithm. Our algorithm has an additional property called immediate decision: at each time, it is immediately decided for each newly released job if it will be scheduled, and if so, then also the time interval and machine where it is scheduled is fixed and cannot be changed later. We show that for two machines, no deterministic algorithm with immediate decision is better than 1.8-competitive; this lower bound shows that our algorithm is optimal for m = 2 in this restricted model. We give some additional lower bounds for algorithms with immediate decision.","Title: Optimal Resource Augmentations for Online Knapsack\nYear: 2007\n\nAbstract: It is known that online knapsack is not competitive. This negative result remains true even if the items are removable. In this paper we consider online removable knapsack with resource augmentation, in which we hold a knapsack of capacity R茂戮驴 1.0 and aim at maintaining a feasible packing to maximize the total weight of the items packed. Accepted items can be removed to leave room for newly arriving items. Once an item is rejected/removed it can not be considered again. We evaluate an online algorithm by comparing the resulting packing to an optimal packing that uses a knapsack of capacity one. Optimal online algorithms are derived for both the weighted case (items have arbitrary weights) and the un-weighted case (the weight of an item is equal to its size).","Title: A new version of on-line variable-sized bin packing\nYear: 1997\n\nAbstract: This paper investigates a new version of the on-line variable-sized bin packing problem. Suppose that bin capacities can vary. Given a list of items, the goal is to pack items in the bins which arrive in an on-line way such that the total size of bins used is minimized. It is shown that next fit and first fit (decreasing) algorithms all have a worst-case performance bound of 2.","Title: Scheduling on two identical machines with a speed-up resource.\nYear: 2011\n\nAbstract: We address a variant of scheduling problem on two identical machines, where we are given an additional speed-up resource. If a job uses the resource, its processing time may decrease. However, at any time the resource can only be used by at most one job. The objective is to minimize the makespan. For the offline version, we present an FPTAS. For the online version where jobs arrive over list, we propose an online algorithm with competitive ratio of 1.781, and show a lower bound of 1.686 for any online algorithm.","Title: Maximizing the Total Profit of Rectangles Packed into a Rectangle\nYear: 2007\n\nAbstract: We consider the following rectangle packing problem. Given a set of rectangles, each of which is associated with a profit, we are requested to pack a subset of the rectangles into a bigger rectangle so that the total profit of rectangles packed is maximized. The rectangles may not overlap. This problem is strongly NP-hard even for packing squares with identical profits. We first present a simple (3 + ε)-approximation algorithm. Then we consider a restricted version of the problem and show a (2 + ε)-approximation algorithm. This restricted problem includes the case where rotation by 90° is allowed (and is possible), and the case of packing squares. We apply a similar technique to the general problem, and get an improved algorithm with a worst-case ratio of at most 5/2 + ε. Finally, we devise a (2 + ε)-approximation algorithm for the general problem.","Title: Vehicle Scheduling on a Graph Revisited.\nYear: 2012\n\nAbstract: We consider a generalization of the well-known Traveling Salesman Problem, called the Vehicle Scheduling Problem (VSP), in which each city is associated with a release time and a service time. The salesman has to visit each city at or after its release time. Our main results are three-fold. First, we devise an approximation algorithm for VSP with performance ratio less than 5/2 when the number of distinct release times is fixed, improving the previous algorithm proposed by Nagamochi et al. [12]. Then we analyze a natural class of algorithms and show that no performance ratio better than 5/2 is possible unless the Metric TSP can be approximated with a ratio strictly less than 3/2, which is a well-known longstanding open question. Finally, we consider a special case of VSP, that has a heavy edge, and present an approximation algorithm with performance ratio less than 5/2 as well.","Title: Approximation algorithms for a bi-level knapsack problem\nYear: 2011\n\nAbstract: In this paper, we consider a variant of knapsack problem. There are two knapsacks with probably different capacities, owned by two agents respectively. Given a set of items, each with a fixed size and a profit, the two agents select items and pack them into their own knapsacks under the capacity constraint. Same items can be packed simultaneously to different knapsacks. However, in this case the profit of such items can vary. One agent packs items into his knapsack to maximize the total profit, while another agent can only pack items into his knapsack as well but he cares the total profits of items packed into two knapsacks. The latter agent is a leader while the former is a follower. We aim at designing an approximation algorithm for the leader assuming that the follower is selfish. For different settings we provide approximation results.","Title: Approximation algorithms for scheduling with a variable machine maintenance\nYear: 2010\n\nAbstract: In this paper, we investigate the problem of scheduling weighted jobs on a single machine with a maintenance whose starting time is prior to a given deadline and whose duration is a nondecreasing function of the starting time. We are asked not only to schedule the jobs but also the maintenance such that the total weighted job completion time is minimum. The problem is shown to be weakly NP-hard. In the case that the duration of the maintenance is a concave (and nondecreasing) function of its starting time, we provide two approximation algorithms with approximation ratio of 2 and at most 1 + √2/2 + ε, respectively.","Title: On-Line Extensible Bin Packing with Unequal Bin Sizes\nYear: 2003\n\nAbstract: In the extensible bin packing problem we are asked to pack a set of items into a given number of bins, each with an original size. However, the original bin sizes can be extended if necessary. The goal is to minimize the total size of the bins. We consider the problem with unequal (original) bin sizes and give the complete analysis on a list scheduling algorithm (LS). Namely we present tight bounds of LS for every collection of original bin sizes and every number of bins. We further show better on-line algorithms for the two-bin case and the three-bin case. Interestingly, it is proved that the on-line algorithms have better competitive ratios for unequal bins than for equal bins. Some variants of the problem are also discussed.","Title: On-line scheduling of multi-core processor tasks with virtualization\nYear: 2010\n\nAbstract: We consider an on-line list scheduling problem of multi-core processor tasks with virtualization to minimize makespan. The competitive ratio of an on-line algorithm is shown for every specific m, where m is the number of processors. Better on-line algorithms are presented for a small number of processors.","Title: Approximation schemes for two-machine flow shop scheduling with two agents\nYear: 2012\n\nAbstract: In this paper we consider two-machine flow shop scheduling with two agents. Two models are investigated. One is the weighted-sum optimization model and the other is the constrained optimization model. For the former, we show that it is weakly NP-hard and propose a fully polynomial time approximation scheme. For the latter, we also show the problem is weakly NP-hard. With violating the constraint a factor of 驴 a fully polynomial time approximation scheme is provided.","Title: Strip Packing vs. Bin Packing\nYear: 2006\n\nAbstract: In this paper we establish a general algorithmic framework between bin packing and strip packing, with which we achieve the same asymptotic bounds by applying bin packing algorithms to strip packing. More precisely we obtain the following results: (1) Any offline bin packing algorithm can be applied to strip packing maintaining the same asymptotic worst-case ratio. Thus using FFD (First Fit Decreasing Height) as a subroutine, we get a practical (simple and fast) algorithm for strip packing with an upper bound 11/9. (2) A class of Harmonic-based algorithms for bin packing can be applied to online strip packing maintaining the same asymptotic competitive ratio. It implies online strip packing admits an upper bound of 1.58889 on the asymptotic competitive ratio. This significantly improves the previously best bound of 1.6910 and affirmatively answers an open question posed in [5] .","Title: Parameterized on-line open-end bin packing\nYear: 1998\n\nAbstract: This note deals with a new variant of bin packing, the so-called open-end bin packing problem in which a bin can be filled\n to a level exceeding its capacity by its last item if it is not full immediately before the last is packed. We investigate\n the on-line version of this problem and give best possible algorithms for parametric cases.","Title: Approximating the optimal competitive ratio for an ancient online scheduling problem\nYear: 2013\n\nAbstract: We consider the classical online scheduling problem P||C_{max} in which jobs are released over list and provide a nearly optimal online algorithm. More precisely, an online algorithm whose competitive ratio is at most (1+\\epsilon) times that of an optimal online algorithm could be achieved in polynomial time, where m, the number of machines, is a part of the input. It substantially improves upon the previous results by almost closing the gap between the currently best known lower bound of 1.88 (Rudin, Ph.D thesis, 2001) and the best known upper bound of 1.92 (Fleischer, Wahl, Journal of Scheduling, 2000). It has been known by folklore that an online problem could be viewed as a game between an adversary and the online player. Our approach extensively explores such a structure and builds up a completely new framework to show that, for the online over list scheduling problem, given any \\epsilon>0, there exists a uniform threshold K which is polynomial in m such that if the competitive ratio of an online algorithm is \\rho<=2, then there exists a list of at most K jobs to enforce the online algorithm to achieve a competitive ratio of at least \\rho-O(\\epsilon). Our approach is substantially different from that of Gunther et al. (Gunther et al., SODA 2013), in which an approximation scheme for online over time scheduling problems is given, where the number of machines is fixed. Our method could also be extended to several related online over list scheduling models.","Title: A Harmonic Algorithm for the 3D Strip Packing Problem.\nYear: 2013\n\nAbstract: In the three-dimensional (3D) strip packing problem, we are given a set of 3D rectangular items and a 3D box B. The goal is to pack all the items in B such that the height of the packing is minimized. We consider the most basic version of the problem, where the items must be packed with their edges parallel to the edges of B and cannot be rotated. Building upon Caprara's work for the two-dimensional (2D) bin packing problem, we obtain an algorithm that, given any epsilon > 0, achieves an approximation of T-infinity + epsilon approximate to 1.69103 + epsilon, where T-infinity is the well-known number that occurs naturally in the context of bin packing. Our key idea is to establish a connection between bin packing solutions for an arbitrary instance I and the strip packing solutions for the corresponding instance obtained from I by applying the harmonic transformation to certain dimensions. Based on this connection, we also give a simple alternate proof of the T-infinity + epsilon approximation for 2D bin packing due to Caprara. In particular, we show how his result follows from a simple modification of the asymptotic approximation scheme for 2D strip packing due to Kenyon and Remila.","Title: A new upper bound 2.5545 on 2D Online Bin Packing\nYear: 2011\n\nAbstract: The 2D Online Bin Packing is a fundamental problem in Computer Science and the determination of its asymptotic competitive ratio has research attention. In a long series of papers, the lower bound of this ratio has been improved from 1.808, 1.856 to 1.907 and its upper bound reduced from 3.25, 3.0625, 2.8596, 2.7834 to 2.66013. In this article, we rewrite the upper bound record to 2.5545. Our idea for the improvement is as follows. In 2002, Seiden and van Stee [Seiden and van Stee 2003] proposed an elegant algorithm called H ⊗ C, comprised of the Harmonic algorithm H and the Improved Harmonic algorithm C, for the two-dimensional online bin packing problem and proved that the algorithm has an asymptotic competitive ratio of at most 2.66013. Since the best known online algorithm for one-dimensional bin packing is the Super Harmonic algorithm [Seiden 2002], a natural question to ask is: could a better upper bound be achieved by using the Super Harmonic algorithm instead of the Improved Harmonic algorithm? However, as mentioned in Seiden and van Stee [2003], the previous analysis framework does not work. In this article, we give a positive answer for this question. A new upper bound of 2.5545 is obtained for 2-dimensional online bin packing. The main idea is to develop new weighting functions for the Super Harmonic algorithm and propose new techniques to bound the total weight in a rectangular bin.","Title: The hardness of selective network design for bottleneck routing games\nYear: 2007\n\nAbstract: In this paper, motivated by the work of Azar et al. [3] we consider selective network design on bottleneck routing games. Assuming P ≠ NP we achieve the following results. For the unsplittable bottleneck games the trivial algorithm is a best possible approximation algorithm. For the k-splittable unweighted bottleneck games it is NP-hard to compute a best pure-strategy Nash equilibrium. Moreover no polynomial time algorithms can have a constant approximation ratio if the edge latency functions are continuous and non-decreasing.","Title: Online scheduling with hard deadlines on parallel machines\nYear: 2006\n\nAbstract: In this paper, motivated by on-line admission control in the hard deadline model, we deal with the following scheduling problem. We are given m identical machines (multi-streams). All jobs (requests) have identical processing time. Each job is associated with a release time and a deadline, neither of which is known until the job arrives. As soon as a job is available, we must immediately decide if the job is accepted or rejected. If a job is accepted, then it must be completed no later than its deadline. The goal is to maximize the total number of jobs accepted. The one-machine case has been extensively studied while little is known for multiple machines. Our main result is deriving a nontrivial optimal online algorithm with competitive ratio $\\frac{3}{2}$ for the two-machine case by carefully investigating various strategies. Deterministic lower bounds for the general case are also given.","Title: Approximation algorithms for unrelated machine scheduling with an energy budget\nYear: 2011\n\nAbstract: We consider the problem of unrelated parallel machine scheduling when the DVS (dynamic voltage scaling) method is used to conserve energy consumption. Given an energy budget, we present (2+ε)- approximation algorithms for the makespan minimization problem under two different settings, the continuous model in which speeds are allowed to be any real number in [smin, smax] and the discrete model in which only d distinct speeds are available. We also show how to derive a 2- approximation algorithm if the energy budget is allowed to be slightly exceeded.","Title: An improved lower bound for rank four scheduling\nYear: 2014\n\nAbstract: We consider the classical minimum makespan scheduling problem, where the processing time of job j on machine i is p\"i\"j, and the matrix P=(p\"i\"j)\"m\"x\"n is of a low rank. It is proved in Bhaskara et al. (2013) that rank 7 scheduling is NP-hard to approximate to a factor of 3/[email protected], and rank 4 scheduling is APX-hard (a factor of [email protected]). We improve this result by showing that rank 4 scheduling is already NP-hard to approximate within a factor of 3/[email protected]","Title: Online Scheduling Of Mixed Cpu-Gpu Jobs\nYear: 2014\n\nAbstract: We consider the online scheduling problem in a CPU-GPU cluster. In this problem there are two sets of processors, the CPU processors and the GPU processors. Each job has two distinct processing times, one for the CPU processor and the other for the CPU processor. Once a job is released, a decision should be made immediately about which processor it should be assigned to. The goal is to minimize the makespan, i.e., the largest completion time among all the processors. Such a problem could be seen as an intermediate model between the scheduling problem on identical machines and unrelated machines. We provide a 3.85-competitive online algorithm for this problem and show that no online algorithm exists with competitive ratio strictly less than 2. We also consider two special cases of this problem, the balanced case where the number of CPU processors equals to that of CPU processors, and the one-sided case where there is only one CPU or CPU processor. For the balanced case, we first provide a simple 3-competitive algorithm, and then a better algorithm with competitive ratio of 2.732 is derived. For the one-sided case, a 3-competitive algorithm is given.","Title: Approximating the Optimal Algorithm for Online Scheduling Problems via Dynamic Programming.\nYear: 2015\n\nAbstract: Very recently Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] initiate a new systematic way of studying online problems by introducing the competitive ratio approximation scheme (simplified as competitive schemes in this paper), which is a class of algorithms {A(is an element of)vertical bar is an element of> 0} with a competitive ratio at most rho*(1 + is an element of), where rho* is the best possible competitive ratio over all online algorithms. Along this line, Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] provide competitive schemes for several online over time scheduling problems like Qm vertical bar r(j), (pmtn)vertical bar Sigma w(j)c(j), while the running times are polynomial if the number of machines is a constant. In this paper, we consider the classical online scheduling problems, where jobs arrive in a list. We present competitive schemes for Rm parallel to C-max and Rm parallel to Sigma(i) C-i(p), where the running times are polynomial if the number of machines is a constant. Specifically, we are able to derive a competitive scheme for P parallel to C-max which runs in polynomial time even if the number of machines is an input. Our method is novel and more efficient than that of Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] Indeed, by utilizing the standard rounding technique for the off-line scheduling problems, we reformulate the online scheduling problem into a game on an infinite graph, through which we arrive at the following key point: Assuming that the best competitive ratio is rho*, for any online algorithm there exists a list of a polynomial number of jobs showing that its competitive ratio is at least rho* - O(is an element of). Interestingly such a result is achieved via a dynamic programming algorithm. Our framework is also applicable to other online problems.","Title: An Asymptotic Competitive Scheme for Online Bin Packing.\nYear: 2014\n\nAbstract: In the online bin packing problem, a list of items with integral sizes between 1 to B arrive one by one. Each item must be irrevocably assigned into a bin of capacity B upon its arrival without any information on the subsequent items, and the goal is to minimize the number of used bins. In this paper, we deal with online bin packing from a new sight. We present an asymptotic competitive scheme, i.e., for any ¿ 0 , the asymptotic competitive ratio is at most ¿ * + ¿ , where ¿ * is the smallest possible asymptotic competitive ratio among all online algorithms. Apart from the technical results, the analysis to bridge the online and the off-line approaches might be of particular interests.","Title: Packing Groups of Items into Multiple Knapsacks.\nYear: 2018\n\nAbstract: We consider a natural generalization of the classical multiple knapsack problem in which instead of packing single items we are packing groups of items. In this problem, we have multiple knapsacks and a set of items partitioned into groups. Each item has an individual weight, while the profit is associated with groups rather than items. The profit of a group can be attained if and only if every item of this group is packed. Such a general model finds applications in various practical problems, e.g., delivering bundles of goods. The tractability of this problem relies heavily on how large a group could be. Deciding if a group of items of total weight 2 could be packed into two knapsacks of unit capacity is already NP-hard and it thus rules out a constant-approximation algorithm for this problem in general. We then focus on the parameterized version where the total weight of items in each group is bounded by a factor δ of the total capacity of all knapsacks. Both approximation and inapproximability results with respect to δ are derived. We also show that, depending on whether the number of knapsacks is a constant or part of the input, the approximation ratio for the problem, as a function on δ, changes substantially, which has a clear difference from the classical multiple knapsack problem.","Title: Strategy-proof Mechanism Design for Facility Location Games: Revisited (Extended Abstract).\nYear: 2016\n\nAbstract: In facility location games, one aims at designing a mechanism to decide the facility location based on the addresses reported by all agents. In the standard facility location game, each agent wants to minimize the distance from the facility, while in the obnoxious facility game, each agent prefers to be as far away from the facility as possible. In this paper we revisit the two games on a line network by finely defining more reasonable agent cost (utility) functions in terms of their satisfaction degree with respect to the facility location. Namely, a happiness factor within $[0,1]$ is introduced to measure the difference between the best facility location for an agent and the one given by the mechanism. Agents aim at a largest possible happiness factor while the social satisfaction is to maximize the total factors. For the standard facility location game, we observe that the median mechanism [4] is of 3/2-approximation. We then devise a 5/4-approximation group strategy-proof mechanism. For the obnoxious facility game, we show the majority mechanism [1] is best possible with approximation ratio of two.","Title: Mechanism Design for One-Facility Location Game with Obnoxious Effects.\nYear: 2016\n\nAbstract: In classic obnoxious facility games [5,6,12], each agent i has a private location xi on a closed interval [0, 1] and one facility y is planned to build on the interval according to the bids of all the agents. In this paper we consider obnoxious effects among the game by introducing two thresholds d(1) and d(2) into utility functions, where 0 <= d(1) <= d(2) <= 1. Let d(y, x(i)) = |y - x(i)| be the distance between agent i and facility y. The utility function of agent i is 0 if d(y, x(i)) is at most d(1); 1 if d(y, x(i)) is at least d(2); otherwise a linear increasing function between 0 and 1. Each agent aims to get a largest possible utility while the social welfare is to maximize the sum of all the agents' utilities. The classic obnoxious facility game is a special case of our problem when d(1) = 0 and d(2) = 1. We show that if d(1) = d(2), a mechanism that outputs the leftmost optimal facility location is strategy-proof. If d(1) >= 1/2, we show the problem cannot have any bounded deterministic strategy-proof mechanism. By further detailed analysis, if the thresholds d(1), d(2) are restricted to some ranges, we design strategy-proof mechanisms and provide the approximation ratios with respect to d(1) and d(2).","Title: Approximate composable truthful mechanism design.\nYear: 2016\n\nAbstract: This paper aims to study techniques for designing truthful mechanisms for a combinatorial optimization problem that might require composition algorithms. We show that the composition algorithm A∘B is monotone if the algorithm A and the algorithm B are both monotone. We apply this technique to the two-dimensional orthogonal knapsack problem with provable constant approximation bounds, improving the previous non-constant results in [5]. Moreover, we show that the technique can also be applied to the heterogeneous multiple clusters scheduling problem, and a truthful mechanism with provable approximation bounds was presented.","Title: Approximation Algorithms for Parallel Machine Scheduling with Speed-up Resources.\nYear: 2016\n\nAbstract: We consider the problem of scheduling with renewable speed-up resources. Given m identical machines, n jobs and c different discrete resources, the task is to schedule each job non-preemptively onto one of the machines so as to minimize the makespan. In our problem, a job has its original processing time, which could be reduced by utilizing one of the resources. As resources are different, the amount of the time reduced for each job is different depending on the resource it uses. Once a resource is being used by one job, it can not be used simultaneously by any other job until this job is finished, hence the scheduler should take into account the job-to-machine assignment together with the resource-to-job assignment.We observe that, the classical unrelated machine scheduling problem is actually a special case of our problem when m=c, i.e., the number of resources equals the number of machines. Extending the techniques for the unrelated machine scheduling, we give a 2-approximation algorithm when both m and c are part of the input. We then consider two special cases for the problem, with m or c being a constant, and derive PTASes (Polynomial Time Approximation Schemes) respectively. We also establish the relationship between the two parameters m and c, through which we are able to transform the PTAS for the case when m is constant to the case when c is a constant. The relationship between the two parameters reveals the structure within the problem, and may be of independent interest.","Title: An Efficient PTAS for Parallel Machine Scheduling with Capacity Constraints.\nYear: 2016\n\nAbstract: In this paper, we consider the classical scheduling problem on parallel machines with capacity constraints. We are given m identical machines, where each machine k can process up to (c_k) jobs. The goal is to assign the (nle sum _{k=1}^{m}c_k) independent jobs on the machines subject to the capacity constraints such that the makespan is minimized. This problem is a generalization of the c-partition problem where (c_k=c) for each machine. The c-partition problem is strongly NP-hard for (cge 3) and the best known approximation algorithm of which has a performance ratio of 4 / 3 due to Babel et al. [2]. For the general problem where machines could have different capacities, the best known result is a 1.5-approximation algorithm with running time (O(nlog n+m^2n)) [14]. In this paper, we improve the previous result substantially by establishing an efficient polynomial time approximation scheme (EPTAS). The key idea is to establish a non-standard ILP (Integer Linear Programming) formulation for the scheduling problem, where a set of crucial constraints (called proportional constraints) is introduced. Such constraints, along with a greedy rounding technique, allow us to derive an integer solution from a relaxed fractional one without violating constraints.","Title: Algorithmic Analysis for Ridesharing of Personal Vehicles.\nYear: 2018\n\nAbstract: The ridesharing problem is to share personal vehicles by individuals with similar itineraries. A trip in the ridesharing problem is an individual and his/her itinerary. To realize a trip is to deliver the individual to his/her destination by a vehicle satisfying the itinerary requirement. Major optimization goals in the ridesharing problem include minimizing the number of vehicles and minimizing the total travel distance of vehicles to realize all trips. There are many parameters in the minimization problems, making them complex and NP-hard. The problems can be simplified by considering only some of the parameters. We give an algorithmic analysis for the simplified minimization problems and explore a boundary between the NP-hard and polynomial time solvable cases. We prove that the simplified minimization problems, where only the source, destination, vehicle capacity, detour distance and preferred path parameters are considered, are still NP-hard. We show that the simplified problem of minimizing the number of vehicles becomes polynomial time solvable if the considered parameters satisfy certain conditions. These suggest a boundary between the NP-hard and polynomial time solvable cases.","Title: Parameterized and Approximation Results for Scheduling with a Low Rank Processing Time Matrix.\nYear: 2017\n\nAbstract: We study approximation and parameterized algorithms for R vertical bar vertical bar C-max, focusing on the problem when the rank of the matrix formed by job processing times is small. Bhaskara et al. [2] initiated the study of approximation algorithms with respect to the rank, showing that R vertical bar vertical bar C-max admits a QPTAS (Quasi-polynomial time approximation scheme) when the rank is 2, and becomes APX-hard when the rank is 4. We continue this line of research. We prove that R vertical bar vertical bar C(max )is APX-hard even if the rank is 3, resolving an open problem in [2]. We then show that R vertical bar vertical bar C-max is FPT parameterized by the rank and the largest job processing time p(maz). This generalizes the parameterized results on P vertical bar vertical bar C-max [17] and R vertical bar vertical bar C-max with few different types of machines [15]. We also provide nearly tight lower bounds under Exponential Time Hypothesis which suggests that the running time of the FPT algorithm is unlikely to be improved significantly.","Title: Efficient Algorithms for Ridesharing of Personal Vehicles.\nYear: 2017\n\nAbstract: Given a set of trips in a road network, where each trip has an individual, a vehicle and some requirements, the ridesharing problem is to select a subset of vehicles to deliver the individuals of all trips to their destinations satisfying the requirements. Common requirements of a trip include the source, destination, vehicle capacity, detour distance limit, preferred paths, and time constraints of the trip. Minimizing the total travel distance of the vehicles and minimizing the number of vehicles are major optimization goals. These minimization problems are complex and NP-hard because each trip may have many requirements. We study simplified minimization problems in which each trip's requirements are specified by the source, destination, vehicle capacity, detour distance and preferred path parameters. We show that both minimization problems can be solved in polynomial time if all of the following conditions are satisfied: (1) all trips have the same destination or same source; (2) no detour is allowed and (3) each trip has one unique preferred path. It is known that both minimization problems are NP-hard if any one of the three conditions is not satisfied. Our results and the NP-hard results suggest a boundary between the polynomial time solvable cases and NP-hard cases for the minimization problems.","Title: Online lazy bureaucrat scheduling with a machine deadline.\nYear: 2018\n\nAbstract: The lazy bureaucrat scheduling problem was first introduced by Arkin et al. (Inf Comput 184:129–146, ). Since then, a number of variants have been addressed. However, very little is known on the online version. In this note we focus on the scenario of online scheduling, in which the jobs arrive over time. The bureaucrat (machine) has a working time interval. Namely, he has a deadline by which all scheduled jobs must be completed. A decision is only based on released jobs without any information on the future. We consider two objective functions of [] and []. Both admit best possible online algorithms with competitive ratio of .","Title: Parallel machine scheduling with speed-up resources.\nYear: 2018\n\nAbstract: •We study scheduling problems where processing times can be reduced via resources.•We provide a constant approximation algorithm for the general problem.•We provide polynomial time approximation schemes for special cases.•We establish a relationship between the two main parameters of the problem.","Title: On the optimality of exact and approximation algorithms for scheduling problems.\nYear: 2018\n\nAbstract: We consider the classical scheduling problem on parallel identical machines to minimize the makespan. There is a long history of study on this problem, focusing on exact and approximation algorithms. It is thus natural to consider whether these algorithms can be further improved in terms of running times. We provide strong lower bounds on the running times of exact and approximation schemes for the classical scheduling problem based on Exponential Time Hypothesis, showing that the best known approximation and exact algorithms are almost the best possible in terms of the running time.","Title: Mechanism design for one-facility location game with obnoxious effects on a line.\nYear: 2018\n\nAbstract: In this paper, we introduce obnoxious effects into obnoxious facility location games on a line, where each agent i has a private location xi on a closed interval [0,1] and one facility will be built on a location y in the interval according to the bids of all the agents. In addition, there are two thresholds d1 and d2 in the utility function of each agent, where 0≤d1≤d2≤1. Denote d(y,xi)=|y−xi| to be the distance between agent i and the facility on the location y. The utility function of agent i is 0 if d(y,xi) is at most d1; 1 if d(y,xi) is at least d2; otherwise a linear increasing function between 0 and 1. Each agent attempts to get the largest utility while the social welfare is to maximize the sum of all the agents' utilities.","Title: Online scheduling of moldable parallel tasks.\nYear: 2018\n\nAbstract: In this paper, we study an online scheduling problem with moldable parallel tasks on m processors. Each moldable task can be processed simultaneously on any number of processors of a parallel computer, and the processing time of a moldable task depends on the number of processors allotted to it. Tasks arrive one by one. Upon arrival of each task, the scheduler has to determine both the number of processors and the starting time for the task. Moreover, these decisions cannot be changed in the future. The objective is to attain a schedule such that the longest completion time over all tasks, i.e., the makespan, is minimized. First, we provide a general framework to show that any \\(\\rho \\)-bounded algorithm for scheduling of rigid parallel tasks (the number of processors for a task is fixed a prior) can be extended to yield an algorithm for scheduling of moldable tasks with a competitive ratio of \\(4\\rho \\) if the ratio \\(\\rho \\) is known beforehand. As a consequence, we achieve the first constant competitive ratio, 26.65, for the moldable parallel tasks scheduling problem. Next, we provide an improved algorithm with a competitive ratio of at most 16.74.","Title: On-Line Scheduling of Parallel Jobs\nYear: 2004\n\nAbstract: We study an on-line parallel job scheduling problem, where jobs arrive over list. A parallel job may require a number of machines for its processing at the same time. Upon arrival of a job, its processing time and the number of requested machines become known, and it must be scheduled immediately without any knowledge of future jobs. We present a 8-competitive on-line algorithm, which improves the previous upper bound of 12 by Johannes [8]. Furthermore, we investigate two special cases in which jobs arrive in non-increasing order of processing times or jobs arrive in non-increasing order of sizes. Better bounds are shown.","Title: A New Upper Bound on 2D Online Bin Packing\nYear: 2009\n\nAbstract: The 2D Online Bin Packing is a fundamental problem in Computer Science and\nthe determination of its asymptotic competitive ratio has attracted great\nresearch attention. In a long series of papers, the lower bound of this ratio\nhas been improved from 1.808, 1.856 to 1.907 and its upper bound reduced from\n3.25, 3.0625, 2.8596, 2.7834 to 2.66013. In this paper, we rewrite the upper\nbound record to 2.5545. Our idea for the improvement is as follows. In SODA\n2002 \\cite{SS03}, Seiden and van Stee proposed an elegant algorithm called $H\n\\otimes B$, comprised of the {\\em Harmonic algorithm} $H$ and the {\\em Improved\nHarmonic algorithm} $B$, for the two-dimensional online bin packing problem and\nproved that the algorithm has an asymptotic competitive ratio of at most\n2.66013. Since the best known online algorithm for one-dimensional bin packing\nis the {\\em Super Harmonic algorithm} \\cite{S02}, a natural question to ask is:\ncould a better upper bound be achieved by using the Super Harmonic algorithm\ninstead of the Improved Harmonic algorithm? However, as mentioned in\n\\cite{SS03}, the previous analysis framework does not work. In this paper, we\ngive a positive answer for the above question. A new upper bound of 2.5545 is\nobtained for 2-dimensional online bin packing. The main idea is to develop new\nweighting functions for the Super Harmonic algorithm and propose new techniques\nto bound the total weight in a rectangular bin.","Title: Strategy-proof mechanisms for obnoxious facility game with bounded service range.\nYear: 2019\n\nAbstract: In this paper, we study the obnoxious facility game with a limited service capacity on a line network, in which all facilities are undesirable and necessary for agents, such as the garbage dumps. The limited service capacity restricts each facility only to serve the agents in its service radius \\(r> 0\\). All agents prefer to be far away from facilities, but still to be served by a facility. Namely, the distance between an agent and her nearest facility is at most r. In a deterministic or randomized mechanism, based on the addresses reported by the selfish agents, the locations or the location distributions of facilities are determined. The aim of the mechanisms is to maximize the obnoxious social welfare, the total distance between all agents and the facilities, on the premise of each agent being served. On the other hand, each agent tries to maximize her own utility, i.e., the distance from the facility, and she may lie if, by doing so, to get strictly more benefit. We are interested in mechanisms without money to elicit the true location profile (strategy-proofness or group strategy-proofness) and maximize the obnoxious social welfare as much as possible. In this paper, we give the first attempt for this game on a closed interval [0, 1], to design group strategy-proof deterministic and randomized mechanisms for the case of \\(\\frac{1}{2}\\le r\\le 1\\). The approximation ratios, depending on the radius r, of different mechanisms are explored. We also provide the lower bounds on approximation ratios of deterministic strategy-proof mechanisms.","Title: Multiple Constrained Routing Algorithms in Large-Scaled Software Defined Networks.\nYear: 2019\n\nAbstract: In this paper, we consider the bandwidth-delay-hop constrained routing problem in large-scaled software defined networks. A number of demands, each of which specifies a source vertex and a sink vertex, are required to route in a given network. We are asked to select a subset of demands, and assign a routing path for each selected demand without violating the hop and delay constraints, while assuring that the bandwidth occupied in each edge is not beyond its capacity. The goal is to maximize the throughput (the total bandwidth) of the selected demands. We develop an efficient heuristic algorithm for the problem, which consists of three main steps, namely, computing feasible paths for each demand, sorting the demands with some priority rules, selecting a path for each demand. The algorithm is tested with networks of actual sizes and topologies, generated by Huawei Technologies Company. The experiments show that the proposed approach outperforms existing algorithms both in throughput and in running time. In the experiments, our algorithm achieves more than 90% of the total bandwidth of the given demands within 10 seconds. Moreover, a large part of our algorithm can run in parallel which largely speeds up the process when using multi-core processors.","Title: Facility location games with distinct desires\nYear: 2019\n\nAbstract: In facility location games, one aims at designing a mechanism to decide the facility location based on the addresses reported by all agents. In the facility location game, each agent wants to minimize his/her distance from the facility, while in the obnoxious facility game, each agent prefers to be as far away from the facility as possible. In this paper we revisit the two games on a line network by finely defining another reasonable agent utility function in terms of their satisfaction degree with respect to the facility location. Namely, a happiness factor within [0,1] is introduced to measure the difference between the best facility location for an agent and the one given by the mechanism. An agent wants to gain a largest possible happiness factor while the social satisfaction is to maximize the sum of the factors. For the facility location game, we first show that the median mechanism (Procaccia and Tennenholtz, 2009) is 32-approximation. We then devise a 54-approximate group strategy-proof mechanism. Subsequently, we investigate the variant of maximizing the smallest happiness factor over all agents for this setting. For the obnoxious facility game, we show that the majority mechanism (Cheng et al., 2011) remains the best possible with approximation ratio of two. Finally, we devise a 43 -approximate randomized mechanism.","Title: Traffic Shaping In E-Commercial Search Engine: Multi-Objective Online Welfare Maximization\nYear: 2021\n\nAbstract: The e-commercial search engine is the primary gateway for customers to find desired products and engage in online shopping. Besides displaying items to optimize for a single objective (i.e., relevance), ranking items needs to satisfy some other business requirements in practice. Recently, traffic shaping was introduced to incorporate multiple objectives in a constrained optimization framework. However, many practical business requirements can not explicitly represented by linear constraints as in the existing work, and this may limit the scalability of their framework. This paper presents a unified framework from the aspect of multi-objective welfare maximization where we regard all business requirements as objectives to optimize. Our framework can naturally incorporate a wide range of application-driven requirements. In addition to formulating the problem, we design an online traffic splitting algorithm that allows us to flexibly adjust the priorities of different objectives, and it has rigorous theoretical guarantees over the adversarial scenario. We also run experiments on both synthetic and real-world datasets to validate our algorithms.","Title: Scheduling With Variable-Length Calibrations: Two Agreeable Variants\nYear: 2021\n\nAbstract: Machines usually require maintenance after running a fixed period. A calibration at a cost has to be performed during the process. Finding a feasible schedule minimizing the total cost of calibrations is of great importance. In this paper, we deal with a single machine scheduling model with K types of calibrations. A calibration of type kappa is an element of {1, ..., K} can be made instantaneously at any time point, which incurs a cost f(kappa) and can keep the machine active for a length T-kappa. Given a set of n jobs with release times, deadlines, and processing times, the goal is to minimize the total cost of calibrations by assigning all jobs in the calibrated state, where job preemption is allowed.We investigate two agreeable settings. Regarding agreeable jobs, later release times imply later deadlines. We establish a pseudo-polynomial time optimal algorithm and a (3 + epsilon)-approximation algorithm. Moreover, if the largest job processing time is no more than any calibration length, it admits a (2 + epsilon)-approximation algorithm. As for agreeable calibrations, where the cost of each calibration is proportional to its length, a 2-approximation algorithm is presented. (C) 2021 Elsevier B.V. All rights reserved.","Title: Approximation Algorithms for Interdiction Problem with Packing Constraints\nYear: 2022\n\nAbstract: We study a bilevel optimization problem which is a zero-sum Stackelberg game. In this problem, there are two players, a leader and a follower, who pick items from a common set. Both the leader and the follower have their own (multi-dimensional) budgets, respectively. Each item is associated with a profit, which is the same to the leader and the follower, and will consume the leader's (follower's) budget if it is selected by the leader (follower). The leader and the follower will select items in a sequential way: First, the leader selects items within the leader's budget. Then the follower selects items from the remaining items within the follower's budget. The goal of the leader is to minimize the maximum profit that the follower can obtain. Let $s_A$ and $s_B$ be the dimension of the leader's and follower's budget, respectively. A special case of our problem is the bilevel knapsack problem studied by Caprara et al. [SIAM Journal on Optimization, 2014], where $s_A=s_B=1$. We consider the general problem and obtain an $(s_B+\\epsilon)$-approximation algorithm when $s_A$ and $s_B$ are both constant. In particular, if $s_B=1$, our algorithm implies a PTAS for the bilevel knapsack problem, which is the first O(1)-approximation algorithm. We also complement our result by showing that there does not exist any $(4/3-\\epsilon)$-approximation algorithm even if $s_A=1$ and $s_B=2$. We also consider a variant of our problem with resource augmentation when $s_A$ and $s_B$ are both part of the input. We obtain an O(1)-approximation algorithm with O(1)-resource augmentation, that is, we give an algorithm that returns a solution which exceeds the given leader's budget by O(1) times, and the objective value achieved by the solution is O(1) times the optimal objective value that respects the leader's budget.","Title: Truthful mechanism design for bin packing with applications on cloud computing\nYear: 2022\n\nAbstract: In this paper, we study a mechanism design for the bin packing problem, which can model a reversed auction on cloud computing. A cloud computing platform has a set of jobs and would like to rent VM instances to process these jobs from cloud providers. In the auction model, each cloud provider (agent) who owns VM instances will submit a bid on the costs for using such VM instances. The mechanism determines the number of VM instances from each agent, and payments that have to be paid for using the chosen VM instances. The utility of an agent is the payment received minus the true cost. Our proposed mechanism is a deterministic truthful mechanism that the utility of each agent is maximized by revealing the true cost. Next, we provide the analysis of the approximation ratios, and then run experiments using both realistic workload and uniformly random data to show the performance of the proposed mechanisms."],"string":"[\n \"Title: Improved approximation algorithms for routing shop scheduling\\nYear: 2011\\n\\nAbstract: We investigate a generalization of classical shop scheduling where n jobs are located at the vertices of a general undirected graph and m machines must travel between the vertices to process the jobs. The aim is to minimize the makespan. For the open shop problem, we develop an O(logmloglogm)-approximation algorithm that significantly improves upon the best known $O(\\\\sqrt{m})$-approximation algorithm. For the flow shop problem, we present an O(m2/3)-approximation algorithm that improves upon the best known $\\\\max\\\\{\\\\frac{m+1}{2},\\\\rho\\\\}$-approximation algorithm, where ρ is the approximation factor for metric TSP.\",\n \"Title: A note on online strip packing\\nYear: 2009\\n\\nAbstract: In online strip packing we are asked to pack a list of rectangles one by one into a vertical strip of unit width, without\\n any information about future rectangles. The goal is to minimize the total height of strip used. The best known algorithm\\n is First Fit Shelf algorithm (Baker and Schwarz in SIAM J. Comput. 12(3):508–525, 1983), which has an absolute competitive ratio of 6.99 under the assumption that the height of each rectangle is bounded from\\n above by one. We improve the shelf algorithm and show an absolute competitive ratio of \\n \\n without the restriction on rectangle heights. Our algorithm also beats the best known online algorithm for parallel job scheduling.\",\n \"Title: Obnoxious Facility Game with a Bounded Service Range.\\nYear: 2013\\n\\nAbstract: We study the obnoxious facility game with service range on a path where each facility is undesirable and has service radius r. In this game there are a number of agents on a path. Each agent tries to be far away from all facilities, but still to be served by a facility. Namely, the distance between an agent and her nearest facility is at most r. The utility of an agent is thus defined as this distance. In a deterministic or randomized mechanism, based on the addresses reported by the selfish agents, the locations or the location distributions of facilities are determined. The aim of the mechanisms is to maximize the obnoxious social welfare, the total utilities of all agents. The objective of each agent is to maximize her own utility and she may lie if, by doing so, more benefit can be obtained. We are interested in mechanisms without money to decide the facility locations so that the obnoxious social welfare is maximized and all agents are enforced to report their true locations (strategy-proofness or group strategy-proof ness). In this paper, we give the first attempt for this game on a path to design a group strategy-proof deterministic and randomized mechanism when the service radius 1/2 ≤ r ≤ 1 by assuming that the path length is one. Depending on the value r, we provide different mechanisms with provable approximation ratios. Lower bounds on any deterministic strategy-proof mechanism are also presented. © Springer-Verlag Berlin Heidelberg 2013.\",\n \"Title: An on-line bin-batching problem\\nYear: 2001\\n\\nAbstract: In this note we consider a new problem, the so-called bin-batching problem related to variable-sized bin covering. A best possible on-line algorithm is presented.\",\n \"Title: Online Removable Square Packing\\nYear: 2008\\n\\nAbstract: The online removable square packing problem is a two dimensional version of the online removable Knapsack problem. For a sequence\\n of squares with side length at most 1, we are requested to pack a subset of them into a unit square in an online fashion where\\n the online player can decide whether to take the current square or not and which squares currently in the unit square to remove.\\n The goal is to maximize the total packed area. Our results include: (i) Any online algorithm cannot achieve a better competitive\\n ratio than (Ö</font\\n>5+3)/2 »</font\\n> 2.618\\\\sqrt{5}+3)/2 \\\\approx 2.618. (ii) The matching upper bound is achieved by a relatively simple online algorithm if repacking is allowed. (iii) Without\\n repacking, we can achieve an upper bound of 3 by using the concept of bricks by Januszewski and Lassak [11]. (iv) The offline version of the problem admits a PTAS.\",\n \"Title: Online multiple-strip packing\\nYear: 2011\\n\\nAbstract: We study an online multiple-strip packing problem, whose goal is to pack the given rectangles into m vertical strips of unit width such that the maximum height used among the strips is minimized. Rectangles arrive one by one. The decision of delivering the rectangles to a strip as well as packing them into the strip must be done immediately and irrevocably without any information on the next rectangles. Both randomized and deterministic online algorithms are investigated, all of which are guaranteed a constant competitive ratio.\",\n \"Title: Strategy-proof approximation mechanisms for an obnoxious facility game on networks\\nYear: 2013\\n\\nAbstract: We study a new facility game, namely, an obnoxious facility game, on a network where the facility is undesirable and all agents try to be as far away from the facility as possible. The following process is considered: at first the agents declare their locations, then, given these bids, a mechanism selects a place on the network to locate the facility. The aim of the mechanism is to maximize the obnoxious social welfare, i.e., the total distance between the agents and the facility. The objective of each agent is to maximize his/her utility, i.e., the distance from the facility. Thus an agent may lie if, by doing so, he/she can get strictly more benefit. We are interested in mechanisms without money to decide the facility location so that the obnoxious social welfare is maximized and all agents are enforced to report their true locations. In this paper we give a first attempt at this game on different networks. Our main results are the following. When the network is a path, we show a 3-approximation group strategy-proof deterministic mechanism which is best possible if the facility can only take one of the endpoints on the path, and a group strategy-proof randomized mechanism with tight approximation ratio of 32. When the networks are a circle (known as a ring in the case of computer networks) and a tree, we propose two group strategy-proof deterministic mechanisms that each provides the approximation ratio of 3. Furthermore, when all agents are on a general network, we propose a 4-approximation group strategy-proof deterministic mechanism and a 2-approximation group strategy-proof randomized mechanism.\",\n \"Title: A new approximation algorithm for UET-Scheduling with chain-type precedence constraints\\nYear: 1998\\n\\nAbstract: Jansen et al. [Jansen, K., Woeginger, G. J. and Yu, Z., UET-Scheduling with chain-type precedence constraints . Report 277, Technische Universität Graz, Institut für Mathematik, Graz, Austria, 1993.] studied the U2Chain problem in which two processors are given and all jobs have unit processing time; every job can be executed on only one machine; there are chain-type precedence constraints among the jobs and the objective is to minimize the makespan. This problem arises from the job-system where different jobs require different resources, thus a job may be processed only on some special machine. Since the problem is strongly NP-hard, they gave an approximation algorithm with performance ratio of 5/3. The purpose of our paper is to improve their result by giving a new approximation algorithm with a worst-case guarantee 3/2 for this problem. In this paper a new approximation algorithm with worst case performance ratio 3/2 is presented for the problem of scheduling unit execution time jobs on two parallel machines with the objective of minimizing the makespan where each job can be processed on only one machine and there are chain-type precedence constraints in the jobs. This result answers an open problem in Jansen et al. [Jansen, K., Woeginger, G. J. and Yu, Z., UET-Scheduling with chain-type precedence constraints . Report 277, Technische Universität Graz, Institut für Mathematik, Graz, Austria, 1993.]: “Does there exist a polynomial time heuristic with worst-case guarantee better than 5/3 for the problem U2Chain?”. The new approximation algorithm is also applied to the problem J 2| pmtn | C max .\",\n \"Title: Single machine batch scheduling to minimize the sum of total flow time and batch delivery cost with an unavailability interval.\\nYear: 2014\\n\\nAbstract: This paper addresses the problem of scheduling n nonresumable and simultaneously available jobs on a single machine, where the machine has a fixed unavailability interval, and the jobs are delivered in batches to the customers. There is no capacity limit on each delivery batch, and the cost per batch delivery is fixed and independent of the number of jobs in the batch. The goal is to find the optimal delivery date for each job and an optimal job sequence to minimize the sum of total flow time and batch delivery cost. The problem is shown to be NP-hard based on a reduction from the Equal-Size Partition Problem. Then a pseudo-polynomial time algorithm is developed, establishing that it is NP-hard in the ordinary sense. Finally, by applying the interval partitioning technique and the rounding technique, a fully polynomial time approximation scheme (FPTAS) and a bicriteria fully polynomial time approximation scheme are developed, which run in time On5ε2+n5logn and On6ε, respectively.\",\n \"Title: Scheduling with a minimum number of machines\\nYear: 2009\\n\\nAbstract: We investigate the scheduling problem with release dates and deadlines on a minimum number of machines. In the case of equal release dates, we present a 2-approximation algorithm. We also show that Greedy Best-Fit (GBF) is a 6-approximation algorithm for the case of equal processing times.\",\n \"Title: On the optimality of approximation schemes for the classical scheduling problem\\nYear: 2013\\n\\nAbstract: We consider the classical scheduling problem on parallel identical machines to minimize the makespan. There is a long history of studies on this problem, focusing on exact and approximation algorithms, and it is thus natural to consider whether these algorithms are best possible in terms of the running time. Under the Exponential Time Hypothesis (ETH), we achieve the following results in this paper: • The scheduling problem on a constant number m of identical machines, which is denoted as Pm||Cmax, is known to admit a fully polynomial time approximation scheme (FPTAS) of running time O(n) + (1/ε)O(m) (indeed, the algorithm works for an even more general problem where machines are unrelated). We prove this algorithm is essentially the best possible in the sense that a (1/ε)O(m1-δ) + nO(1) time FPTAS for any δ > 0 implies that ETH fails. • The scheduling problem on an arbitrary number of identical machines, which is denoted as P||Cmax, is known to admit a polynomial time approximation scheme (PTAS) of running time 2O(1/ε2 log3(1/ε))+nO(1). We prove this algorithm is nearly optimal in the sense that a 2O((1/ε)1-δ+nO(1) time PTAS for any δ > 0 implies that ETH fails, leaving a small room for improvement. In addition, we also consider exact algorithms for the scheduling problem and prove the following result: • The traditional dynamic programming algorithm for P||Cmax is known to run in 2O(n) time. We prove this is essentially the best possible in the sense that even if we restrict that there are n jobs and the processing time of each job is bounded by O(n), an exact algorithm of running time 22O(n1-δ) for any δ > 0 implies that ETH fails. To obtain these results we will provide two new reductions from 3SAT, one for Pm||Cmax and another for P||Cmax. Indeed, the new reductions explore the structure of scheduling problems and can also lead to other interesting results. For example, using the framework of our reduction for P||Cmax, Chen et al. [5] are able to prove the APX-hardness of the scheduling problem in which the matrix of job processing times P = (pij)mxn is of rank 3, solving the open problem mentioned in [2].\",\n \"Title: Online Scheduling on a CPU-GPU Cluster.\\nYear: 2013\\n\\nAbstract: We consider the online scheduling problem in a CPU-GPU cluster. In this problem there are two sets of processors, the CPU processors and GPU processors. Each job has two distinct processing times, one for the CPU processor and the other for the GPU processor. Once a job is released, a decision should be made immediately about which processor it should be assigned to. The goal is to minimize the makespan, i.e., the largest completion time among all the processors. Such a problem could be seen as an intermediate model between the scheduling problem on identical machines and unrelated machines. We provide a 3.85-competitive online algorithm for this problem and show that no online algorithm exists with competitive ratio strictly less than 2. We also consider two special cases of this problem, the balanced case where the number of CPU processors equals to that of GPU processors, and the one-sided case where there is only one CPU or GPU processor. We provide a (1 + v3)-competitive algorithm for the balanced case, and a 3-competitive algorithm for the one-sided case. © Springer-Verlag Berlin Heidelberg 2013.\",\n \"Title: On-line scheduling of parallel jobs on two machines\\nYear: 2008\\n\\nAbstract: We study the problem of on-line scheduling of parallel jobs on two machines. The jobs are parallel in the sense that each of them specifies the number of processors, in this case 1 or 2, required for simultaneous processing. The jobs are presented one by one. Upon receiving a job, we must assign the job to a time slot in the schedule before the next job is presented. No re-assignment is allowed. The goal is to minimize the makespan of the final schedule. There is a straightforward algorithm which achieves a competitive ratio of 2. In this paper we show that no on-line algorithm can have a competitive ratio less than 1+2/3(~1.816). We also study two special cases of the problem: (i) Jobs arrive in a non-decreasing order of processing times where we give an optimal algorithm with competitive ratio 3/2; (ii) Jobs arrive in a non-increasing order of processing times where we show that no on-line algorithm has a competitive ratio less than 9/7 and give a greedy algorithm with a competitive ratio 4/3.\",\n \"Title: On-line scheduling of parallel jobs in a list\\nYear: 2007\\n\\nAbstract: We study an on-line parallel job scheduling problem, where jobs arrive one by one. A parallel job may require a number of machines for its processing at the same time. Upon arrival of a job, its processing time and the number of requested machines become known, and it must be scheduled immediately without any knowledge of future jobs. We present a 7-competitive on-line algorithm, which improves the previous upper bound of 12 by Johannes (J. Sched. 9:433---452, 2006). Furthermore, we investigate a special case in which the largest processing time is known beforehand.\",\n \"Title: A Note on Online Scheduling for Jobs with Arbitrary Release Times\\nYear: 2009\\n\\nAbstract: We investigate the problem of on-line scheduling for jobs with arbitrary release times on m identical parallel machines. The goal is to minimize the makespan. We derive a best possible online algorithm with competitive ratio of 2 for m = 2. For a special case that all the jobs have unit processing times, we prove that Algorithm LS has a tight bound of 3/2 for general m machines.\",\n \"Title: A constrained minimum spanning tree problem\\nYear: 2000\\n\\nAbstract: In this paper, we give an O(n(2)) algorithm for finding a point on a given line I which, if added to a given set of n points located on one side of l, will result in the minimum spanning tree.\",\n \"Title: Mechanisms for obnoxious facility game on a path\\nYear: 2011\\n\\nAbstract: We consider a new facility game, namely, an obnoxious facility game where the facility is undesirable and all agents try to be as far away from the facility as possible. The social cost is the total distance between the agents and the facility. However, an obnoxious facility is placed based on the reported locations of the selfish agents. We are interested in a mechanism to decide the facility location so that the social cost is maximized. In this paper, we give a first attempt for this game on a path. Our main results include a 3-approximation group strategy-proof deterministic mechanism, which is best possible if the facility can only take one of the endpoints on the path, and two group strategy-proof randomized mechanisms with approximation ratio of 5/3 and 3/2, respectively\",\n \"Title: Harmonic algorithm for 3-dimensional strip packing problem\\nYear: 2007\\n\\nAbstract: In the three dimensional strip packing problem, we are given a set of three-dimensional rectangular items I = {(xi, yi, zi) : i = 1, ..., n} and a three dimensional box B. The goal is to pack all the items in the box B without any overlap, such that the height of the packing is minimized. We consider the most basic version of the problem, where the items must be packed with their edges parallel to the edges of B and cannot be rotated. Building upon Caprara's work [4] for the two dimensional bin packing problem we obtain an approximation algorithm with a similar performance guarantee of T∞ ≈ 1.69 where T∞ is the well known Harmonic number that occurs naturally in the context of bin packing. The previously known approximation algorithms for this problem had worst case performance guarantees of 2 [7], 2.64 [14], 2.67 [15], 2.89 [10] and 3.25 [11]. Our second algorithm is an asymptotic PTAS for the case in which all items have square bases.\",\n \"Title: Maximizing the Number of Packed Rectangles\\nYear: 2004\\n\\nAbstract: Given a set of rectangles we are asked to pack as many of them as possible into a bigger rectangle. The rectangles packed may not overlap and may not be rotated. This problem is NP-hard in the strong sense even for packing squares into a square. We establish the relationship between the asymptotic worst-case ratio and the (absolute) worst-case ratio for the problem. It is proved that there exists an asymptotic FPTAS, and thus a PTAS, for packing squares into a rectangle. We give an approximation algorithm with asymptotic ratio of at most two for packing rectangles, and further show a simple (2 + epsilon)-approximation algorithm.\",\n \"Title: On-line scheduling mesh jobs with dependencies\\nYear: 2007\\n\\nAbstract: We study an on-line problem of scheduling parallel jobs on two-dimensional meshes. Parallel jobs arrive dynamically according to the dependencies between them, which are unknown before the jobs appear. Each job may need more than one processor simultaneously and is required to be scheduled on a submesh of the processors which are located on a two-dimensional mesh, i.e., a job must be scheduled on a rectangle of given dimensions. The objective is to minimize the maximum completion time (makespan). We deal with a UET job system, in which all job processing times are equal. We show a lower bound of 3.859 and present a 5.25-competitive algorithm. It significantly improves a previous lower bound of 3.25 and a previous upper bound of 46/7. We consider also the rotated two-dimensional mesh, in which the parallel jobs can be rotated and the rotation of all the jobs is feasible. A lower bound of 3.535 is proven and an on-line algorithm with competitive ratio of at most 4.25 is derived.\",\n \"Title: Common deadline lazy bureaucrat scheduling revisited\\nYear: 2006\\n\\nAbstract: Lazy bureaucrat scheduling is a new class of scheduling problems introduced by Arkin et al. [1]. In this paper we focus on the case where all the jobs share a common deadline. Such a problem is denoted as CD-LBSP, which has been considered by Esfahbod et al. [2]. We first show that the worst-case ratio of the algorithm SJF (Shortest Job First) is two under the objective function [min-time-spent], and thus answer an open question posed in [2]. We further present two approximation schemes Ak and Bk both having worst-case ratio of $\\\\frac{k+1}{k}$, for any given integer k0, under the objective function [min-makespan] and [min-time-spent] respectively. Finally, we prove that the problem CD-LBSP remains NP-hard under several objective functions, even if all jobs share the same release time.\",\n \"Title: Deterministic on-line call control in cellular networks\\nYear: 2010\\n\\nAbstract: We study an on-line call control problem in cellular networks that are based on the Frequency Division Multiplexing (FDM) technology. In such networks, interference may occur when the same frequency is assigned to two different calls emanating from the same cell or its neighboring cells. The number of frequencies supporting the networks is limited. The goal is to maximize the number of calls served without causing any interference. We focus on the case that the number of frequencies is sufficiently large and the calls stay forever. We give a deterministic on-line algorithm with asymptotic competitive ratio of 2.5 and show a general lower bound of 2. For the special case of linear cellular networks, we achieve a best possible deterministic on-line algorithm with asymptotic competitive ratio of 3/2.\",\n \"Title: Optimal on-line algorithms for variable-sized bin covering\\nYear: 1999\\n\\nAbstract: We deal with the variable-sized bin covering problem: Given a list L of items in (0,1] and a finite collection B of feasible bin sizes, the goal is to select a set of bins with sizes in B and to cover them with the items in L such that the total size of the covered bins is maximized. In the on-line version of this problem, the items must be assigned to bins one by one without previewing future items. This note presents a complete solution to the on-line problem: For every collection B of bin sizes, we give an on-line approximation algorithm with a worst-case ratio r(B), and we prove that no on-line algorithm can perform better in the worst case. The value r(B) mainly depends on the largest gap between consecutive bin sizes.\",\n \"Title: Linear time-approximation algorithms for bin packing\\nYear: 2000\\n\\nAbstract: Simchi-Levi (Naval Res. Logist. 41 (1994) 579-585) proved that the famous bin packing algorithms FF and BF have an absolute worst-case ratio of no more than 74, and FFD and BFD have an absolute worst-case ratio of 32, respectively. These algorithms run in time O(nlogn). In this paper, we provide a linear time constant space (number of bins kept during the execution of the algorithm is constant) off-line approximation algorithms with absolute worst-case ratio 32. This result is best possible unless P=NP. Furthermore, we present a linear time constant space on-line algorithm and prove that the absolute worst-case ratio is 74.\",\n \"Title: Maximizing the throughput of parallel jobs on hypercubes\\nYear: 2007\\n\\nAbstract: We study a problem of scheduling n independent parallel jobs on hypercubes. A parallel job is required to be scheduled on a subcube of processors. All jobs are available at the beginning, each of which is associated with a due date. The objective is to maximize the total number of early jobs. We provide an optimal polynomial time algorithm for the unit processing time job system.\",\n \"Title: New Upper Bounds on The Approximability of 3D Strip Packing\\nYear: 2006\\n\\nAbstract: In this paper, we study the 3D strip packing problem in which we are given a list of 3- dimensional boxes and required to pack all of them into a 3-dimensional strip with length 1 and width 1 and unlimited height to minimize the height used. Our results are below: i) we give an approximation algorithm with asymptotic worst-case ratio 1.69103, which improves the previous best bound of 2 + ǫ by Jansen and Solis-Oba of SODA 2006; ii) we also present an asymptotic PTAS for the case in which all items have square bases.\",\n \"Title: Bin Packing of Selfish Items\\nYear: 2008\\n\\nAbstract: We study a bin packing game in which any item to be packed is handled by a selfish agent. Each agent aims at minimizing his sharing cost with the other items staying in the same bin, where the social cost is the number of bins used. We first show that computing a pure Nash equilibrium can be done in polynomial time. We then prove that the price of anarchy for the game is in between 1.6416 and 1.6575, improving the previous bounds.\",\n \"Title: Hardness of lazy packing and covering\\nYear: 2009\\n\\nAbstract: We prove APX-hardness for the two problems maximum resource bin packing and lazy bin covering. Simple algorithms matching the best absolute bounds under the assumption PNP are also derived.\",\n \"Title: Online Scheduling of Parallel Jobs with Dependencies on 2-Dimensional Meshes\\nYear: 2003\\n\\nAbstract: We study an on-line problem of scheduling parallel jobs on 2-dimensional meshes. Parallel jobs arrive dynamically according to the dependencies between them, which are unknown before the jobs appear. Each job may need more than one processor simultaneously and is required to be scheduled on a submesh of the processors which are located on a 2-dimensional mesh, i.e., a job must be scheduled on a rectangle of given dimensions. The objective is to minimize the maximum completion time (makespan). We deal with an UET job system, in which all job processing times are equal. We show a lower bound of 3.859 and present a 5.25-competitive algorithm. It significantly improves a previous lower bound of 3.25 and a previous upper bound of 46/7. We consider also the rotated 2-dimensional mesh, in which the parallel jobs can be rotated. A lower bound of 3.535 is proven and an on-line algorithm with competitive ratio of at most 4.25 is derived.\",\n \"Title: Offline Scheduling of Multi-threaded Request Streams on a Caching Server\\nYear: 2011\\n\\nAbstract: In this work, we are interested in the problem of satisfying multiple concurrent requests submitted to a computing server. Informally, there are users each sending a sequence of requests to the server. The requests consist of tasks linked by precedence constraints. Tasks may occur several times in the same sequence as well as in a request sequence of another user. The computing server has to execute tasks with variable processing times. The server owns a cache of limited size where intermediate results of the processing may be stored. If an intermediate result for a task is stored into the cache, no processing cost has to be paid and the result can directly be fetched from the cache. The goal of this work is to determine a schedule of the tasks such that an optimization function is minimized (the only objective studied up to now is the make span). This problem is a variant of caching which considers only one sequence of requests. We then extend the study to the minimization of the mean completion time of the request sequences. Two models are considered. In the first model, caching is forced whereas in the second model caching is optional and one can choose whether an intermediate result is stored in the cache or not. All combinations turn out to be NP-hard for fixed cache sizes and we provide a formulation as dynamic program as well as bounds for in approximation. We propose polynomial time approximation algorithms for some variants and analyze their approximation ratios. Finally, we also devise some heuristics and present experimental results. Tasks may occur several times in the same sequence as well as in a request sequence of another user. The computing server has to execute tasks with variable processing times. The server owns a cache of limited size where intermediate results of the processing may be stored. If an intermediate result for a task is stored into the cache, no processing cost has to be paid and the result can directly be fetched from the cache. The goal of this work is to determine a schedule of the tasks such that an optimization function is minimized (the only objective studied up to now is the make span). This problem is a variant of caching which considers only one sequence of requests. We then extend the study to the minimization of the mean completion time of the request sequences. Two models are considered. In the first model, caching is forced whereas in the second model caching is optional and one can choose whether an intermediate result is stored in the cache or not. All combinations turn out to be NP-hard for fixed cache sizes and we provide a formulation as dynamic program as well as bounds for in approximation. We propose polynomial time approximation algorithms for some variants and analyze their approximation ratios. Finally, we also devise some heuristics and present experimental results.\",\n \"Title: A 3-approximation algorithm for two-dimensional bin packing\\nYear: 2005\\n\\nAbstract: In the classical two-dimensional bin packing problem one is asked to pack a set of rectangular items, without overlap and without any rotation, into the minimum number of identical square bins. We give an approximation algorithm with absolute worst-case ratio of 3.\",\n \"Title: Online knapsack with resource augmentation\\nYear: 2010\\n\\nAbstract: It is known that online knapsack is not competitive. This negative result remains true even if items are removable. In this paper we consider online removable knapsack with resource augmentation, in which we hold a knapsack of capacity R=1 and aim at maintaining a feasible packing to maximize the total profit of items packed into the knapsack. Both scenarios that removal of accepted items is allowed and is not allowed are investigated. We evaluate an online algorithm by comparing the resulting packing to an optimal packing that uses a knapsack of capacity one. Optimal online algorithms are derived for both the weighted case (items have arbitrary profits) and the unweighted case (the profit of an item is equal to its size).\",\n \"Title: On-Line Multiple-Strip Packing\\nYear: 2009\\n\\nAbstract: We study the multiple-strip packing problem, in which the goal is to pack all the rectangles into m vertical strips of unit widths such that the maximum height among strips used is minimized. A number of on-line algorithms for this problem are proposed, in which the decision of delivering the rectangles to strips as well as packing the rectangles in strips must be done on-line. Both randomized and deterministic on-line algorithms are investigated, and all of them are guaranteed to have constant competitive ratios.\",\n \"Title: A note on scheduling with low rank processing times.\\nYear: 2013\\n\\nAbstract: We consider the classical minimum makespan scheduling problem, where the processing time of job $j$ on machine $i$ is $p_{ij}$, and the matrix $P=(p_{ij})_{m\\\\times n}$ is of a low rank. It is proved in (Bhaskara et al., SODA 2013) that rank 7 scheduling is NP-hard to approximate to a factor of $3/2-\\\\epsilon$, and rank 4 scheduling is APX-hard (NP-hard to approximate within a factor of $1.03-\\\\epsilon$). We improve this result by showing that rank 4 scheduling is already NP-hard to approximate within a factor of $3/2-\\\\epsilon$, and meanwhile rank 3 scheduling is APX-hard.\",\n \"Title: On lazy bureaucrat scheduling with common deadlines\\nYear: 2008\\n\\nAbstract: Lazy bureaucrat scheduling is a new class of scheduling problems introduced by Arkin et al. (Inf. Comput. 184:129–146, 2003). In this paper we focus on the case where all the jobs share a common deadline. Such a problem is denoted as CD-LBSP, which\\n has been considered by Esfahbod et al. (Algorithms and data structures. Lecture notes in computer science, vol. 2748, pp. 59–66,\\n 2003). We first show that the worst-case ratio of the algorithm SJF (Shortest Job First) is two under the objective function [min-time-spent], and thus answer an open question posed in (Esfahbod, et al. in Algorithms and data structures. Lecture notes in computer\\n science, vol. 2748, pp. 59–66, 2003). We further present two approximation schemes A\\n \\n k\\n and B\\n \\n k\\n both having worst-case ratio of \\n \\n , for any given integer k>0, under the objective functions [min-makespan] and [min-time-spent], respectively. Finally, we prove that the problem CD-LBSP remains NP-hard under several objective functions, even if all\\n jobs share the same release time.\",\n \"Title: Optimal online-list batch scheduling\\nYear: 2009\\n\\nAbstract: We consider the online-list batch scheduling problem. Jobs arrive one by one and have to be assigned upon arrival to a scheduled batch such that the makespan is minimized. Each batch can accommodate up to B jobs. We give a complete classification of the tractability of this online problem.\",\n \"Title: A simple semi on-line algorithm for P2//Cmax with a buffer\\nYear: 1997\\n\\nAbstract: In this paper, we investigate a semi on-line version of the parallel machine scheduling problem. We are given a buffer of length k which is available to maintain k jobs. The jobs arrive one by one and can be temporarily assigned to the buffer if the buffer is not full. The goal is to assign all jobs to the identical machines such that the makespan is minimized. For two machines, Kellerer et al. (1995) showed that no heuristic for this problem can have a worst-case ratio lower than 43. This paper presents a simple algorithm with worst-case ratio 43 for P2//Cmax with a buffer of length 1.\",\n \"Title: On-line scheduling with extendable working time on a small number of machines\\nYear: 2003\\n\\nAbstract: Speranza and Tuza [Ann. Oper. Res. 86 (1999) 494-506] studied the on-line problem of scheduling jobs on m identical machines with extendable working time. In this problem, each machine is assumed to have an identical regular working time, which can be extended if necessary. The working time of a machine is the larger one between its regular working time and the total processing time of jobs assigned to it. The objective is to minimize the total working time of machines. They presented an on-line algorithm Hx, with a competitive ratio at most 1.228 for any number of machines by choosing an appropriate parameter x. In this paper we consider a small number of machines. The best choices of x are given for m = 2, 3, 4 and the tight bounds, 7/6, 11/9 and 19/16, respectively, are proved. Among them, the algorithm for m = 2 is best possible. We then derive a new algorithm for m = 3 with a competitive ratio 7/6.\",\n \"Title: On Two Dimensional Orthogonal Knapsack Problem\\nYear: 2008\\n\\nAbstract: In this paper, we study the following knapsack problem: Given a list of squares with profits, we are requested to pack a sublist of them into a rectangular bin (not a unit square bin) to make profits in the bin as large as possible. We first observe there is a Polynomial Time Approximation Scheme (PTAS) for the problem of packing weighted squares into rectangular bins with large resources, then apply the PTAS to the problem of packing squares with profits into a rectangular bin and get a 6 5 + ǫ approximation algorithm.\",\n \"Title: Online scheduling of equal-length jobs on parallel machines\\nYear: 2007\\n\\nAbstract: We study on-line scheduling of equal-length jobs on parallel machines. Our main result is an algorithm with competitive ratio decreasing to e/(e - 1) ≅ 1.58 as the number of machine increases. For m ≥ 3, this is the first algorithm better than 2-competitive greedy algorithm. Our algorithm has an additional property called immediate decision: at each time, it is immediately decided for each newly released job if it will be scheduled, and if so, then also the time interval and machine where it is scheduled is fixed and cannot be changed later. We show that for two machines, no deterministic algorithm with immediate decision is better than 1.8-competitive; this lower bound shows that our algorithm is optimal for m = 2 in this restricted model. We give some additional lower bounds for algorithms with immediate decision.\",\n \"Title: Optimal Resource Augmentations for Online Knapsack\\nYear: 2007\\n\\nAbstract: It is known that online knapsack is not competitive. This negative result remains true even if the items are removable. In this paper we consider online removable knapsack with resource augmentation, in which we hold a knapsack of capacity R茂戮驴 1.0 and aim at maintaining a feasible packing to maximize the total weight of the items packed. Accepted items can be removed to leave room for newly arriving items. Once an item is rejected/removed it can not be considered again. We evaluate an online algorithm by comparing the resulting packing to an optimal packing that uses a knapsack of capacity one. Optimal online algorithms are derived for both the weighted case (items have arbitrary weights) and the un-weighted case (the weight of an item is equal to its size).\",\n \"Title: A new version of on-line variable-sized bin packing\\nYear: 1997\\n\\nAbstract: This paper investigates a new version of the on-line variable-sized bin packing problem. Suppose that bin capacities can vary. Given a list of items, the goal is to pack items in the bins which arrive in an on-line way such that the total size of bins used is minimized. It is shown that next fit and first fit (decreasing) algorithms all have a worst-case performance bound of 2.\",\n \"Title: Scheduling on two identical machines with a speed-up resource.\\nYear: 2011\\n\\nAbstract: We address a variant of scheduling problem on two identical machines, where we are given an additional speed-up resource. If a job uses the resource, its processing time may decrease. However, at any time the resource can only be used by at most one job. The objective is to minimize the makespan. For the offline version, we present an FPTAS. For the online version where jobs arrive over list, we propose an online algorithm with competitive ratio of 1.781, and show a lower bound of 1.686 for any online algorithm.\",\n \"Title: Maximizing the Total Profit of Rectangles Packed into a Rectangle\\nYear: 2007\\n\\nAbstract: We consider the following rectangle packing problem. Given a set of rectangles, each of which is associated with a profit, we are requested to pack a subset of the rectangles into a bigger rectangle so that the total profit of rectangles packed is maximized. The rectangles may not overlap. This problem is strongly NP-hard even for packing squares with identical profits. We first present a simple (3 + ε)-approximation algorithm. Then we consider a restricted version of the problem and show a (2 + ε)-approximation algorithm. This restricted problem includes the case where rotation by 90° is allowed (and is possible), and the case of packing squares. We apply a similar technique to the general problem, and get an improved algorithm with a worst-case ratio of at most 5/2 + ε. Finally, we devise a (2 + ε)-approximation algorithm for the general problem.\",\n \"Title: Vehicle Scheduling on a Graph Revisited.\\nYear: 2012\\n\\nAbstract: We consider a generalization of the well-known Traveling Salesman Problem, called the Vehicle Scheduling Problem (VSP), in which each city is associated with a release time and a service time. The salesman has to visit each city at or after its release time. Our main results are three-fold. First, we devise an approximation algorithm for VSP with performance ratio less than 5/2 when the number of distinct release times is fixed, improving the previous algorithm proposed by Nagamochi et al. [12]. Then we analyze a natural class of algorithms and show that no performance ratio better than 5/2 is possible unless the Metric TSP can be approximated with a ratio strictly less than 3/2, which is a well-known longstanding open question. Finally, we consider a special case of VSP, that has a heavy edge, and present an approximation algorithm with performance ratio less than 5/2 as well.\",\n \"Title: Approximation algorithms for a bi-level knapsack problem\\nYear: 2011\\n\\nAbstract: In this paper, we consider a variant of knapsack problem. There are two knapsacks with probably different capacities, owned by two agents respectively. Given a set of items, each with a fixed size and a profit, the two agents select items and pack them into their own knapsacks under the capacity constraint. Same items can be packed simultaneously to different knapsacks. However, in this case the profit of such items can vary. One agent packs items into his knapsack to maximize the total profit, while another agent can only pack items into his knapsack as well but he cares the total profits of items packed into two knapsacks. The latter agent is a leader while the former is a follower. We aim at designing an approximation algorithm for the leader assuming that the follower is selfish. For different settings we provide approximation results.\",\n \"Title: Approximation algorithms for scheduling with a variable machine maintenance\\nYear: 2010\\n\\nAbstract: In this paper, we investigate the problem of scheduling weighted jobs on a single machine with a maintenance whose starting time is prior to a given deadline and whose duration is a nondecreasing function of the starting time. We are asked not only to schedule the jobs but also the maintenance such that the total weighted job completion time is minimum. The problem is shown to be weakly NP-hard. In the case that the duration of the maintenance is a concave (and nondecreasing) function of its starting time, we provide two approximation algorithms with approximation ratio of 2 and at most 1 + √2/2 + ε, respectively.\",\n \"Title: On-Line Extensible Bin Packing with Unequal Bin Sizes\\nYear: 2003\\n\\nAbstract: In the extensible bin packing problem we are asked to pack a set of items into a given number of bins, each with an original size. However, the original bin sizes can be extended if necessary. The goal is to minimize the total size of the bins. We consider the problem with unequal (original) bin sizes and give the complete analysis on a list scheduling algorithm (LS). Namely we present tight bounds of LS for every collection of original bin sizes and every number of bins. We further show better on-line algorithms for the two-bin case and the three-bin case. Interestingly, it is proved that the on-line algorithms have better competitive ratios for unequal bins than for equal bins. Some variants of the problem are also discussed.\",\n \"Title: On-line scheduling of multi-core processor tasks with virtualization\\nYear: 2010\\n\\nAbstract: We consider an on-line list scheduling problem of multi-core processor tasks with virtualization to minimize makespan. The competitive ratio of an on-line algorithm is shown for every specific m, where m is the number of processors. Better on-line algorithms are presented for a small number of processors.\",\n \"Title: Approximation schemes for two-machine flow shop scheduling with two agents\\nYear: 2012\\n\\nAbstract: In this paper we consider two-machine flow shop scheduling with two agents. Two models are investigated. One is the weighted-sum optimization model and the other is the constrained optimization model. For the former, we show that it is weakly NP-hard and propose a fully polynomial time approximation scheme. For the latter, we also show the problem is weakly NP-hard. With violating the constraint a factor of 驴 a fully polynomial time approximation scheme is provided.\",\n \"Title: Strip Packing vs. Bin Packing\\nYear: 2006\\n\\nAbstract: In this paper we establish a general algorithmic framework between bin packing and strip packing, with which we achieve the same asymptotic bounds by applying bin packing algorithms to strip packing. More precisely we obtain the following results: (1) Any offline bin packing algorithm can be applied to strip packing maintaining the same asymptotic worst-case ratio. Thus using FFD (First Fit Decreasing Height) as a subroutine, we get a practical (simple and fast) algorithm for strip packing with an upper bound 11/9. (2) A class of Harmonic-based algorithms for bin packing can be applied to online strip packing maintaining the same asymptotic competitive ratio. It implies online strip packing admits an upper bound of 1.58889 on the asymptotic competitive ratio. This significantly improves the previously best bound of 1.6910 and affirmatively answers an open question posed in [5] .\",\n \"Title: Parameterized on-line open-end bin packing\\nYear: 1998\\n\\nAbstract: This note deals with a new variant of bin packing, the so-called open-end bin packing problem in which a bin can be filled\\n to a level exceeding its capacity by its last item if it is not full immediately before the last is packed. We investigate\\n the on-line version of this problem and give best possible algorithms for parametric cases.\",\n \"Title: Approximating the optimal competitive ratio for an ancient online scheduling problem\\nYear: 2013\\n\\nAbstract: We consider the classical online scheduling problem P||C_{max} in which jobs are released over list and provide a nearly optimal online algorithm. More precisely, an online algorithm whose competitive ratio is at most (1+\\\\epsilon) times that of an optimal online algorithm could be achieved in polynomial time, where m, the number of machines, is a part of the input. It substantially improves upon the previous results by almost closing the gap between the currently best known lower bound of 1.88 (Rudin, Ph.D thesis, 2001) and the best known upper bound of 1.92 (Fleischer, Wahl, Journal of Scheduling, 2000). It has been known by folklore that an online problem could be viewed as a game between an adversary and the online player. Our approach extensively explores such a structure and builds up a completely new framework to show that, for the online over list scheduling problem, given any \\\\epsilon>0, there exists a uniform threshold K which is polynomial in m such that if the competitive ratio of an online algorithm is \\\\rho<=2, then there exists a list of at most K jobs to enforce the online algorithm to achieve a competitive ratio of at least \\\\rho-O(\\\\epsilon). Our approach is substantially different from that of Gunther et al. (Gunther et al., SODA 2013), in which an approximation scheme for online over time scheduling problems is given, where the number of machines is fixed. Our method could also be extended to several related online over list scheduling models.\",\n \"Title: A Harmonic Algorithm for the 3D Strip Packing Problem.\\nYear: 2013\\n\\nAbstract: In the three-dimensional (3D) strip packing problem, we are given a set of 3D rectangular items and a 3D box B. The goal is to pack all the items in B such that the height of the packing is minimized. We consider the most basic version of the problem, where the items must be packed with their edges parallel to the edges of B and cannot be rotated. Building upon Caprara's work for the two-dimensional (2D) bin packing problem, we obtain an algorithm that, given any epsilon > 0, achieves an approximation of T-infinity + epsilon approximate to 1.69103 + epsilon, where T-infinity is the well-known number that occurs naturally in the context of bin packing. Our key idea is to establish a connection between bin packing solutions for an arbitrary instance I and the strip packing solutions for the corresponding instance obtained from I by applying the harmonic transformation to certain dimensions. Based on this connection, we also give a simple alternate proof of the T-infinity + epsilon approximation for 2D bin packing due to Caprara. In particular, we show how his result follows from a simple modification of the asymptotic approximation scheme for 2D strip packing due to Kenyon and Remila.\",\n \"Title: A new upper bound 2.5545 on 2D Online Bin Packing\\nYear: 2011\\n\\nAbstract: The 2D Online Bin Packing is a fundamental problem in Computer Science and the determination of its asymptotic competitive ratio has research attention. In a long series of papers, the lower bound of this ratio has been improved from 1.808, 1.856 to 1.907 and its upper bound reduced from 3.25, 3.0625, 2.8596, 2.7834 to 2.66013. In this article, we rewrite the upper bound record to 2.5545. Our idea for the improvement is as follows. In 2002, Seiden and van Stee [Seiden and van Stee 2003] proposed an elegant algorithm called H ⊗ C, comprised of the Harmonic algorithm H and the Improved Harmonic algorithm C, for the two-dimensional online bin packing problem and proved that the algorithm has an asymptotic competitive ratio of at most 2.66013. Since the best known online algorithm for one-dimensional bin packing is the Super Harmonic algorithm [Seiden 2002], a natural question to ask is: could a better upper bound be achieved by using the Super Harmonic algorithm instead of the Improved Harmonic algorithm? However, as mentioned in Seiden and van Stee [2003], the previous analysis framework does not work. In this article, we give a positive answer for this question. A new upper bound of 2.5545 is obtained for 2-dimensional online bin packing. The main idea is to develop new weighting functions for the Super Harmonic algorithm and propose new techniques to bound the total weight in a rectangular bin.\",\n \"Title: The hardness of selective network design for bottleneck routing games\\nYear: 2007\\n\\nAbstract: In this paper, motivated by the work of Azar et al. [3] we consider selective network design on bottleneck routing games. Assuming P ≠ NP we achieve the following results. For the unsplittable bottleneck games the trivial algorithm is a best possible approximation algorithm. For the k-splittable unweighted bottleneck games it is NP-hard to compute a best pure-strategy Nash equilibrium. Moreover no polynomial time algorithms can have a constant approximation ratio if the edge latency functions are continuous and non-decreasing.\",\n \"Title: Online scheduling with hard deadlines on parallel machines\\nYear: 2006\\n\\nAbstract: In this paper, motivated by on-line admission control in the hard deadline model, we deal with the following scheduling problem. We are given m identical machines (multi-streams). All jobs (requests) have identical processing time. Each job is associated with a release time and a deadline, neither of which is known until the job arrives. As soon as a job is available, we must immediately decide if the job is accepted or rejected. If a job is accepted, then it must be completed no later than its deadline. The goal is to maximize the total number of jobs accepted. The one-machine case has been extensively studied while little is known for multiple machines. Our main result is deriving a nontrivial optimal online algorithm with competitive ratio $\\\\frac{3}{2}$ for the two-machine case by carefully investigating various strategies. Deterministic lower bounds for the general case are also given.\",\n \"Title: Approximation algorithms for unrelated machine scheduling with an energy budget\\nYear: 2011\\n\\nAbstract: We consider the problem of unrelated parallel machine scheduling when the DVS (dynamic voltage scaling) method is used to conserve energy consumption. Given an energy budget, we present (2+ε)- approximation algorithms for the makespan minimization problem under two different settings, the continuous model in which speeds are allowed to be any real number in [smin, smax] and the discrete model in which only d distinct speeds are available. We also show how to derive a 2- approximation algorithm if the energy budget is allowed to be slightly exceeded.\",\n \"Title: An improved lower bound for rank four scheduling\\nYear: 2014\\n\\nAbstract: We consider the classical minimum makespan scheduling problem, where the processing time of job j on machine i is p\\\"i\\\"j, and the matrix P=(p\\\"i\\\"j)\\\"m\\\"x\\\"n is of a low rank. It is proved in Bhaskara et al. (2013) that rank 7 scheduling is NP-hard to approximate to a factor of 3/[email protected], and rank 4 scheduling is APX-hard (a factor of [email protected]). We improve this result by showing that rank 4 scheduling is already NP-hard to approximate within a factor of 3/[email protected]\",\n \"Title: Online Scheduling Of Mixed Cpu-Gpu Jobs\\nYear: 2014\\n\\nAbstract: We consider the online scheduling problem in a CPU-GPU cluster. In this problem there are two sets of processors, the CPU processors and the GPU processors. Each job has two distinct processing times, one for the CPU processor and the other for the CPU processor. Once a job is released, a decision should be made immediately about which processor it should be assigned to. The goal is to minimize the makespan, i.e., the largest completion time among all the processors. Such a problem could be seen as an intermediate model between the scheduling problem on identical machines and unrelated machines. We provide a 3.85-competitive online algorithm for this problem and show that no online algorithm exists with competitive ratio strictly less than 2. We also consider two special cases of this problem, the balanced case where the number of CPU processors equals to that of CPU processors, and the one-sided case where there is only one CPU or CPU processor. For the balanced case, we first provide a simple 3-competitive algorithm, and then a better algorithm with competitive ratio of 2.732 is derived. For the one-sided case, a 3-competitive algorithm is given.\",\n \"Title: Approximating the Optimal Algorithm for Online Scheduling Problems via Dynamic Programming.\\nYear: 2015\\n\\nAbstract: Very recently Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] initiate a new systematic way of studying online problems by introducing the competitive ratio approximation scheme (simplified as competitive schemes in this paper), which is a class of algorithms {A(is an element of)vertical bar is an element of> 0} with a competitive ratio at most rho*(1 + is an element of), where rho* is the best possible competitive ratio over all online algorithms. Along this line, Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] provide competitive schemes for several online over time scheduling problems like Qm vertical bar r(j), (pmtn)vertical bar Sigma w(j)c(j), while the running times are polynomial if the number of machines is a constant. In this paper, we consider the classical online scheduling problems, where jobs arrive in a list. We present competitive schemes for Rm parallel to C-max and Rm parallel to Sigma(i) C-i(p), where the running times are polynomial if the number of machines is a constant. Specifically, we are able to derive a competitive scheme for P parallel to C-max which runs in polynomial time even if the number of machines is an input. Our method is novel and more efficient than that of Gunther et al. [E. Gunther, O. Maurer, N. Megow and A. Wiese (2013). A new approach to online scheduling: Approximating the optimal competitive ratio. In Proc. 24th Annual ACM-SIAM Symp. Discrete Algorithms (SODA).] Indeed, by utilizing the standard rounding technique for the off-line scheduling problems, we reformulate the online scheduling problem into a game on an infinite graph, through which we arrive at the following key point: Assuming that the best competitive ratio is rho*, for any online algorithm there exists a list of a polynomial number of jobs showing that its competitive ratio is at least rho* - O(is an element of). Interestingly such a result is achieved via a dynamic programming algorithm. Our framework is also applicable to other online problems.\",\n \"Title: An Asymptotic Competitive Scheme for Online Bin Packing.\\nYear: 2014\\n\\nAbstract: In the online bin packing problem, a list of items with integral sizes between 1 to B arrive one by one. Each item must be irrevocably assigned into a bin of capacity B upon its arrival without any information on the subsequent items, and the goal is to minimize the number of used bins. In this paper, we deal with online bin packing from a new sight. We present an asymptotic competitive scheme, i.e., for any ¿ 0 , the asymptotic competitive ratio is at most ¿ * + ¿ , where ¿ * is the smallest possible asymptotic competitive ratio among all online algorithms. Apart from the technical results, the analysis to bridge the online and the off-line approaches might be of particular interests.\",\n \"Title: Packing Groups of Items into Multiple Knapsacks.\\nYear: 2018\\n\\nAbstract: We consider a natural generalization of the classical multiple knapsack problem in which instead of packing single items we are packing groups of items. In this problem, we have multiple knapsacks and a set of items partitioned into groups. Each item has an individual weight, while the profit is associated with groups rather than items. The profit of a group can be attained if and only if every item of this group is packed. Such a general model finds applications in various practical problems, e.g., delivering bundles of goods. The tractability of this problem relies heavily on how large a group could be. Deciding if a group of items of total weight 2 could be packed into two knapsacks of unit capacity is already NP-hard and it thus rules out a constant-approximation algorithm for this problem in general. We then focus on the parameterized version where the total weight of items in each group is bounded by a factor δ of the total capacity of all knapsacks. Both approximation and inapproximability results with respect to δ are derived. We also show that, depending on whether the number of knapsacks is a constant or part of the input, the approximation ratio for the problem, as a function on δ, changes substantially, which has a clear difference from the classical multiple knapsack problem.\",\n \"Title: Strategy-proof Mechanism Design for Facility Location Games: Revisited (Extended Abstract).\\nYear: 2016\\n\\nAbstract: In facility location games, one aims at designing a mechanism to decide the facility location based on the addresses reported by all agents. In the standard facility location game, each agent wants to minimize the distance from the facility, while in the obnoxious facility game, each agent prefers to be as far away from the facility as possible. In this paper we revisit the two games on a line network by finely defining more reasonable agent cost (utility) functions in terms of their satisfaction degree with respect to the facility location. Namely, a happiness factor within $[0,1]$ is introduced to measure the difference between the best facility location for an agent and the one given by the mechanism. Agents aim at a largest possible happiness factor while the social satisfaction is to maximize the total factors. For the standard facility location game, we observe that the median mechanism [4] is of 3/2-approximation. We then devise a 5/4-approximation group strategy-proof mechanism. For the obnoxious facility game, we show the majority mechanism [1] is best possible with approximation ratio of two.\",\n \"Title: Mechanism Design for One-Facility Location Game with Obnoxious Effects.\\nYear: 2016\\n\\nAbstract: In classic obnoxious facility games [5,6,12], each agent i has a private location xi on a closed interval [0, 1] and one facility y is planned to build on the interval according to the bids of all the agents. In this paper we consider obnoxious effects among the game by introducing two thresholds d(1) and d(2) into utility functions, where 0 <= d(1) <= d(2) <= 1. Let d(y, x(i)) = |y - x(i)| be the distance between agent i and facility y. The utility function of agent i is 0 if d(y, x(i)) is at most d(1); 1 if d(y, x(i)) is at least d(2); otherwise a linear increasing function between 0 and 1. Each agent aims to get a largest possible utility while the social welfare is to maximize the sum of all the agents' utilities. The classic obnoxious facility game is a special case of our problem when d(1) = 0 and d(2) = 1. We show that if d(1) = d(2), a mechanism that outputs the leftmost optimal facility location is strategy-proof. If d(1) >= 1/2, we show the problem cannot have any bounded deterministic strategy-proof mechanism. By further detailed analysis, if the thresholds d(1), d(2) are restricted to some ranges, we design strategy-proof mechanisms and provide the approximation ratios with respect to d(1) and d(2).\",\n \"Title: Approximate composable truthful mechanism design.\\nYear: 2016\\n\\nAbstract: This paper aims to study techniques for designing truthful mechanisms for a combinatorial optimization problem that might require composition algorithms. We show that the composition algorithm A∘B is monotone if the algorithm A and the algorithm B are both monotone. We apply this technique to the two-dimensional orthogonal knapsack problem with provable constant approximation bounds, improving the previous non-constant results in [5]. Moreover, we show that the technique can also be applied to the heterogeneous multiple clusters scheduling problem, and a truthful mechanism with provable approximation bounds was presented.\",\n \"Title: Approximation Algorithms for Parallel Machine Scheduling with Speed-up Resources.\\nYear: 2016\\n\\nAbstract: We consider the problem of scheduling with renewable speed-up resources. Given m identical machines, n jobs and c different discrete resources, the task is to schedule each job non-preemptively onto one of the machines so as to minimize the makespan. In our problem, a job has its original processing time, which could be reduced by utilizing one of the resources. As resources are different, the amount of the time reduced for each job is different depending on the resource it uses. Once a resource is being used by one job, it can not be used simultaneously by any other job until this job is finished, hence the scheduler should take into account the job-to-machine assignment together with the resource-to-job assignment.We observe that, the classical unrelated machine scheduling problem is actually a special case of our problem when m=c, i.e., the number of resources equals the number of machines. Extending the techniques for the unrelated machine scheduling, we give a 2-approximation algorithm when both m and c are part of the input. We then consider two special cases for the problem, with m or c being a constant, and derive PTASes (Polynomial Time Approximation Schemes) respectively. We also establish the relationship between the two parameters m and c, through which we are able to transform the PTAS for the case when m is constant to the case when c is a constant. The relationship between the two parameters reveals the structure within the problem, and may be of independent interest.\",\n \"Title: An Efficient PTAS for Parallel Machine Scheduling with Capacity Constraints.\\nYear: 2016\\n\\nAbstract: In this paper, we consider the classical scheduling problem on parallel machines with capacity constraints. We are given m identical machines, where each machine k can process up to (c_k) jobs. The goal is to assign the (nle sum _{k=1}^{m}c_k) independent jobs on the machines subject to the capacity constraints such that the makespan is minimized. This problem is a generalization of the c-partition problem where (c_k=c) for each machine. The c-partition problem is strongly NP-hard for (cge 3) and the best known approximation algorithm of which has a performance ratio of 4 / 3 due to Babel et al. [2]. For the general problem where machines could have different capacities, the best known result is a 1.5-approximation algorithm with running time (O(nlog n+m^2n)) [14]. In this paper, we improve the previous result substantially by establishing an efficient polynomial time approximation scheme (EPTAS). The key idea is to establish a non-standard ILP (Integer Linear Programming) formulation for the scheduling problem, where a set of crucial constraints (called proportional constraints) is introduced. Such constraints, along with a greedy rounding technique, allow us to derive an integer solution from a relaxed fractional one without violating constraints.\",\n \"Title: Algorithmic Analysis for Ridesharing of Personal Vehicles.\\nYear: 2018\\n\\nAbstract: The ridesharing problem is to share personal vehicles by individuals with similar itineraries. A trip in the ridesharing problem is an individual and his/her itinerary. To realize a trip is to deliver the individual to his/her destination by a vehicle satisfying the itinerary requirement. Major optimization goals in the ridesharing problem include minimizing the number of vehicles and minimizing the total travel distance of vehicles to realize all trips. There are many parameters in the minimization problems, making them complex and NP-hard. The problems can be simplified by considering only some of the parameters. We give an algorithmic analysis for the simplified minimization problems and explore a boundary between the NP-hard and polynomial time solvable cases. We prove that the simplified minimization problems, where only the source, destination, vehicle capacity, detour distance and preferred path parameters are considered, are still NP-hard. We show that the simplified problem of minimizing the number of vehicles becomes polynomial time solvable if the considered parameters satisfy certain conditions. These suggest a boundary between the NP-hard and polynomial time solvable cases.\",\n \"Title: Parameterized and Approximation Results for Scheduling with a Low Rank Processing Time Matrix.\\nYear: 2017\\n\\nAbstract: We study approximation and parameterized algorithms for R vertical bar vertical bar C-max, focusing on the problem when the rank of the matrix formed by job processing times is small. Bhaskara et al. [2] initiated the study of approximation algorithms with respect to the rank, showing that R vertical bar vertical bar C-max admits a QPTAS (Quasi-polynomial time approximation scheme) when the rank is 2, and becomes APX-hard when the rank is 4. We continue this line of research. We prove that R vertical bar vertical bar C(max )is APX-hard even if the rank is 3, resolving an open problem in [2]. We then show that R vertical bar vertical bar C-max is FPT parameterized by the rank and the largest job processing time p(maz). This generalizes the parameterized results on P vertical bar vertical bar C-max [17] and R vertical bar vertical bar C-max with few different types of machines [15]. We also provide nearly tight lower bounds under Exponential Time Hypothesis which suggests that the running time of the FPT algorithm is unlikely to be improved significantly.\",\n \"Title: Efficient Algorithms for Ridesharing of Personal Vehicles.\\nYear: 2017\\n\\nAbstract: Given a set of trips in a road network, where each trip has an individual, a vehicle and some requirements, the ridesharing problem is to select a subset of vehicles to deliver the individuals of all trips to their destinations satisfying the requirements. Common requirements of a trip include the source, destination, vehicle capacity, detour distance limit, preferred paths, and time constraints of the trip. Minimizing the total travel distance of the vehicles and minimizing the number of vehicles are major optimization goals. These minimization problems are complex and NP-hard because each trip may have many requirements. We study simplified minimization problems in which each trip's requirements are specified by the source, destination, vehicle capacity, detour distance and preferred path parameters. We show that both minimization problems can be solved in polynomial time if all of the following conditions are satisfied: (1) all trips have the same destination or same source; (2) no detour is allowed and (3) each trip has one unique preferred path. It is known that both minimization problems are NP-hard if any one of the three conditions is not satisfied. Our results and the NP-hard results suggest a boundary between the polynomial time solvable cases and NP-hard cases for the minimization problems.\",\n \"Title: Online lazy bureaucrat scheduling with a machine deadline.\\nYear: 2018\\n\\nAbstract: The lazy bureaucrat scheduling problem was first introduced by Arkin et al. (Inf Comput 184:129–146, ). Since then, a number of variants have been addressed. However, very little is known on the online version. In this note we focus on the scenario of online scheduling, in which the jobs arrive over time. The bureaucrat (machine) has a working time interval. Namely, he has a deadline by which all scheduled jobs must be completed. A decision is only based on released jobs without any information on the future. We consider two objective functions of [] and []. Both admit best possible online algorithms with competitive ratio of .\",\n \"Title: Parallel machine scheduling with speed-up resources.\\nYear: 2018\\n\\nAbstract: •We study scheduling problems where processing times can be reduced via resources.•We provide a constant approximation algorithm for the general problem.•We provide polynomial time approximation schemes for special cases.•We establish a relationship between the two main parameters of the problem.\",\n \"Title: On the optimality of exact and approximation algorithms for scheduling problems.\\nYear: 2018\\n\\nAbstract: We consider the classical scheduling problem on parallel identical machines to minimize the makespan. There is a long history of study on this problem, focusing on exact and approximation algorithms. It is thus natural to consider whether these algorithms can be further improved in terms of running times. We provide strong lower bounds on the running times of exact and approximation schemes for the classical scheduling problem based on Exponential Time Hypothesis, showing that the best known approximation and exact algorithms are almost the best possible in terms of the running time.\",\n \"Title: Mechanism design for one-facility location game with obnoxious effects on a line.\\nYear: 2018\\n\\nAbstract: In this paper, we introduce obnoxious effects into obnoxious facility location games on a line, where each agent i has a private location xi on a closed interval [0,1] and one facility will be built on a location y in the interval according to the bids of all the agents. In addition, there are two thresholds d1 and d2 in the utility function of each agent, where 0≤d1≤d2≤1. Denote d(y,xi)=|y−xi| to be the distance between agent i and the facility on the location y. The utility function of agent i is 0 if d(y,xi) is at most d1; 1 if d(y,xi) is at least d2; otherwise a linear increasing function between 0 and 1. Each agent attempts to get the largest utility while the social welfare is to maximize the sum of all the agents' utilities.\",\n \"Title: Online scheduling of moldable parallel tasks.\\nYear: 2018\\n\\nAbstract: In this paper, we study an online scheduling problem with moldable parallel tasks on m processors. Each moldable task can be processed simultaneously on any number of processors of a parallel computer, and the processing time of a moldable task depends on the number of processors allotted to it. Tasks arrive one by one. Upon arrival of each task, the scheduler has to determine both the number of processors and the starting time for the task. Moreover, these decisions cannot be changed in the future. The objective is to attain a schedule such that the longest completion time over all tasks, i.e., the makespan, is minimized. First, we provide a general framework to show that any \\\\(\\\\rho \\\\)-bounded algorithm for scheduling of rigid parallel tasks (the number of processors for a task is fixed a prior) can be extended to yield an algorithm for scheduling of moldable tasks with a competitive ratio of \\\\(4\\\\rho \\\\) if the ratio \\\\(\\\\rho \\\\) is known beforehand. As a consequence, we achieve the first constant competitive ratio, 26.65, for the moldable parallel tasks scheduling problem. Next, we provide an improved algorithm with a competitive ratio of at most 16.74.\",\n \"Title: On-Line Scheduling of Parallel Jobs\\nYear: 2004\\n\\nAbstract: We study an on-line parallel job scheduling problem, where jobs arrive over list. A parallel job may require a number of machines for its processing at the same time. Upon arrival of a job, its processing time and the number of requested machines become known, and it must be scheduled immediately without any knowledge of future jobs. We present a 8-competitive on-line algorithm, which improves the previous upper bound of 12 by Johannes [8]. Furthermore, we investigate two special cases in which jobs arrive in non-increasing order of processing times or jobs arrive in non-increasing order of sizes. Better bounds are shown.\",\n \"Title: A New Upper Bound on 2D Online Bin Packing\\nYear: 2009\\n\\nAbstract: The 2D Online Bin Packing is a fundamental problem in Computer Science and\\nthe determination of its asymptotic competitive ratio has attracted great\\nresearch attention. In a long series of papers, the lower bound of this ratio\\nhas been improved from 1.808, 1.856 to 1.907 and its upper bound reduced from\\n3.25, 3.0625, 2.8596, 2.7834 to 2.66013. In this paper, we rewrite the upper\\nbound record to 2.5545. Our idea for the improvement is as follows. In SODA\\n2002 \\\\cite{SS03}, Seiden and van Stee proposed an elegant algorithm called $H\\n\\\\otimes B$, comprised of the {\\\\em Harmonic algorithm} $H$ and the {\\\\em Improved\\nHarmonic algorithm} $B$, for the two-dimensional online bin packing problem and\\nproved that the algorithm has an asymptotic competitive ratio of at most\\n2.66013. Since the best known online algorithm for one-dimensional bin packing\\nis the {\\\\em Super Harmonic algorithm} \\\\cite{S02}, a natural question to ask is:\\ncould a better upper bound be achieved by using the Super Harmonic algorithm\\ninstead of the Improved Harmonic algorithm? However, as mentioned in\\n\\\\cite{SS03}, the previous analysis framework does not work. In this paper, we\\ngive a positive answer for the above question. A new upper bound of 2.5545 is\\nobtained for 2-dimensional online bin packing. The main idea is to develop new\\nweighting functions for the Super Harmonic algorithm and propose new techniques\\nto bound the total weight in a rectangular bin.\",\n \"Title: Strategy-proof mechanisms for obnoxious facility game with bounded service range.\\nYear: 2019\\n\\nAbstract: In this paper, we study the obnoxious facility game with a limited service capacity on a line network, in which all facilities are undesirable and necessary for agents, such as the garbage dumps. The limited service capacity restricts each facility only to serve the agents in its service radius \\\\(r> 0\\\\). All agents prefer to be far away from facilities, but still to be served by a facility. Namely, the distance between an agent and her nearest facility is at most r. In a deterministic or randomized mechanism, based on the addresses reported by the selfish agents, the locations or the location distributions of facilities are determined. The aim of the mechanisms is to maximize the obnoxious social welfare, the total distance between all agents and the facilities, on the premise of each agent being served. On the other hand, each agent tries to maximize her own utility, i.e., the distance from the facility, and she may lie if, by doing so, to get strictly more benefit. We are interested in mechanisms without money to elicit the true location profile (strategy-proofness or group strategy-proofness) and maximize the obnoxious social welfare as much as possible. In this paper, we give the first attempt for this game on a closed interval [0, 1], to design group strategy-proof deterministic and randomized mechanisms for the case of \\\\(\\\\frac{1}{2}\\\\le r\\\\le 1\\\\). The approximation ratios, depending on the radius r, of different mechanisms are explored. We also provide the lower bounds on approximation ratios of deterministic strategy-proof mechanisms.\",\n \"Title: Multiple Constrained Routing Algorithms in Large-Scaled Software Defined Networks.\\nYear: 2019\\n\\nAbstract: In this paper, we consider the bandwidth-delay-hop constrained routing problem in large-scaled software defined networks. A number of demands, each of which specifies a source vertex and a sink vertex, are required to route in a given network. We are asked to select a subset of demands, and assign a routing path for each selected demand without violating the hop and delay constraints, while assuring that the bandwidth occupied in each edge is not beyond its capacity. The goal is to maximize the throughput (the total bandwidth) of the selected demands. We develop an efficient heuristic algorithm for the problem, which consists of three main steps, namely, computing feasible paths for each demand, sorting the demands with some priority rules, selecting a path for each demand. The algorithm is tested with networks of actual sizes and topologies, generated by Huawei Technologies Company. The experiments show that the proposed approach outperforms existing algorithms both in throughput and in running time. In the experiments, our algorithm achieves more than 90% of the total bandwidth of the given demands within 10 seconds. Moreover, a large part of our algorithm can run in parallel which largely speeds up the process when using multi-core processors.\",\n \"Title: Facility location games with distinct desires\\nYear: 2019\\n\\nAbstract: In facility location games, one aims at designing a mechanism to decide the facility location based on the addresses reported by all agents. In the facility location game, each agent wants to minimize his/her distance from the facility, while in the obnoxious facility game, each agent prefers to be as far away from the facility as possible. In this paper we revisit the two games on a line network by finely defining another reasonable agent utility function in terms of their satisfaction degree with respect to the facility location. Namely, a happiness factor within [0,1] is introduced to measure the difference between the best facility location for an agent and the one given by the mechanism. An agent wants to gain a largest possible happiness factor while the social satisfaction is to maximize the sum of the factors. For the facility location game, we first show that the median mechanism (Procaccia and Tennenholtz, 2009) is 32-approximation. We then devise a 54-approximate group strategy-proof mechanism. Subsequently, we investigate the variant of maximizing the smallest happiness factor over all agents for this setting. For the obnoxious facility game, we show that the majority mechanism (Cheng et al., 2011) remains the best possible with approximation ratio of two. Finally, we devise a 43 -approximate randomized mechanism.\",\n \"Title: Traffic Shaping In E-Commercial Search Engine: Multi-Objective Online Welfare Maximization\\nYear: 2021\\n\\nAbstract: The e-commercial search engine is the primary gateway for customers to find desired products and engage in online shopping. Besides displaying items to optimize for a single objective (i.e., relevance), ranking items needs to satisfy some other business requirements in practice. Recently, traffic shaping was introduced to incorporate multiple objectives in a constrained optimization framework. However, many practical business requirements can not explicitly represented by linear constraints as in the existing work, and this may limit the scalability of their framework. This paper presents a unified framework from the aspect of multi-objective welfare maximization where we regard all business requirements as objectives to optimize. Our framework can naturally incorporate a wide range of application-driven requirements. In addition to formulating the problem, we design an online traffic splitting algorithm that allows us to flexibly adjust the priorities of different objectives, and it has rigorous theoretical guarantees over the adversarial scenario. We also run experiments on both synthetic and real-world datasets to validate our algorithms.\",\n \"Title: Scheduling With Variable-Length Calibrations: Two Agreeable Variants\\nYear: 2021\\n\\nAbstract: Machines usually require maintenance after running a fixed period. A calibration at a cost has to be performed during the process. Finding a feasible schedule minimizing the total cost of calibrations is of great importance. In this paper, we deal with a single machine scheduling model with K types of calibrations. A calibration of type kappa is an element of {1, ..., K} can be made instantaneously at any time point, which incurs a cost f(kappa) and can keep the machine active for a length T-kappa. Given a set of n jobs with release times, deadlines, and processing times, the goal is to minimize the total cost of calibrations by assigning all jobs in the calibrated state, where job preemption is allowed.We investigate two agreeable settings. Regarding agreeable jobs, later release times imply later deadlines. We establish a pseudo-polynomial time optimal algorithm and a (3 + epsilon)-approximation algorithm. Moreover, if the largest job processing time is no more than any calibration length, it admits a (2 + epsilon)-approximation algorithm. As for agreeable calibrations, where the cost of each calibration is proportional to its length, a 2-approximation algorithm is presented. (C) 2021 Elsevier B.V. All rights reserved.\",\n \"Title: Approximation Algorithms for Interdiction Problem with Packing Constraints\\nYear: 2022\\n\\nAbstract: We study a bilevel optimization problem which is a zero-sum Stackelberg game. In this problem, there are two players, a leader and a follower, who pick items from a common set. Both the leader and the follower have their own (multi-dimensional) budgets, respectively. Each item is associated with a profit, which is the same to the leader and the follower, and will consume the leader's (follower's) budget if it is selected by the leader (follower). The leader and the follower will select items in a sequential way: First, the leader selects items within the leader's budget. Then the follower selects items from the remaining items within the follower's budget. The goal of the leader is to minimize the maximum profit that the follower can obtain. Let $s_A$ and $s_B$ be the dimension of the leader's and follower's budget, respectively. A special case of our problem is the bilevel knapsack problem studied by Caprara et al. [SIAM Journal on Optimization, 2014], where $s_A=s_B=1$. We consider the general problem and obtain an $(s_B+\\\\epsilon)$-approximation algorithm when $s_A$ and $s_B$ are both constant. In particular, if $s_B=1$, our algorithm implies a PTAS for the bilevel knapsack problem, which is the first O(1)-approximation algorithm. We also complement our result by showing that there does not exist any $(4/3-\\\\epsilon)$-approximation algorithm even if $s_A=1$ and $s_B=2$. We also consider a variant of our problem with resource augmentation when $s_A$ and $s_B$ are both part of the input. We obtain an O(1)-approximation algorithm with O(1)-resource augmentation, that is, we give an algorithm that returns a solution which exceeds the given leader's budget by O(1) times, and the objective value achieved by the solution is O(1) times the optimal objective value that respects the leader's budget.\",\n \"Title: Truthful mechanism design for bin packing with applications on cloud computing\\nYear: 2022\\n\\nAbstract: In this paper, we study a mechanism design for the bin packing problem, which can model a reversed auction on cloud computing. A cloud computing platform has a set of jobs and would like to rent VM instances to process these jobs from cloud providers. In the auction model, each cloud provider (agent) who owns VM instances will submit a bid on the costs for using such VM instances. The mechanism determines the number of VM instances from each agent, and payments that have to be paid for using the chosen VM instances. The utility of an agent is the payment received minus the true cost. Our proposed mechanism is a deterministic truthful mechanism that the utility of each agent is maximized by revealing the true cost. Next, we provide the analysis of the approximation ratios, and then run experiments using both realistic workload and uniformly random data to show the performance of the proposed mechanisms.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":85,"string":"85"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13344,"string":"13,344"}}},{"rowIdx":13345,"cells":{"question_id":{"kind":"string","value":"Rong Qu"},"question":{"kind":"string","value":"Generate an abstract for the title \"An Efficient Federated Distillation Learning System for Multitask Time Series Classification\" using the following items: 1. Federated distillation learning system\n2. Multitask time series classification\n3. Feature-based student-teacher\n4. Distance-based weights matching\n5. High accuracy and outper"},"answer":{"kind":"string","value":"This article proposes an efficient federated distillation learning system (EFDLS) for multitask time series classification (TSC). EFDLS consists of a central server and multiple mobile users, where different users may run different TSC tasks. EFDLS has two novel components: a feature-based student-teacher (FBST) framework and a distance-based weights matching (DBWM) scheme. For each user, the FBST framework transfers knowledge from its teacher's hidden layers to its student's hidden layers via knowledge distillation, where the teacher and student have identical network structures. For each connected user, its student model's hidden layers' weights are uploaded to the EFDLS server periodically. The DBWM scheme is deployed on the server, with the least square distance (LSD) used to measure the similarity between the weights of two given models. This scheme finds a partner for each connected user such that the user's and its partner's weights are the closest among all the weights uploaded. The server exchanges and sends back the user's and its partner's weights to these two users which then load the received weights to their teachers' hidden layers. Experimental results show that compared with a number of state-of-the-art federated learning (FL) algorithms, our proposed EFDLS wins 20 out of 44 standard UCR2018 datasets and achieves the highest mean accuracy (70.14%) on these datasets. In particular, compared with a single-task baseline, EFDLS obtains 32/4/8 regarding \"win\"/\"tie\"/\"lose\" and results in an improvement of approximately 4% in terms of mean accuracy."},"correct_answer":{"kind":"string","value":"This article proposes an efficient federated distillation learning system (EFDLS) for multitask time series classification (TSC). EFDLS consists of a central server and multiple mobile users, where different users may run different TSC tasks. EFDLS has two novel components: a feature-based student-teacher (FBST) framework and a distance-based weights matching (DBWM) scheme. For each user, the FBST framework transfers knowledge from its teacher's hidden layers to its student's hidden layers via knowledge distillation, where the teacher and student have identical network structures. For each connected user, its student model's hidden layers' weights are uploaded to the EFDLS server periodically. The DBWM scheme is deployed on the server, with the least square distance (LSD) used to measure the similarity between the weights of two given models. This scheme finds a partner for each connected user such that the user's and its partner's weights are the closest among all the weights uploaded. The server exchanges and sends back the user's and its partner's weights to these two users which then load the received weights to their teachers' hidden layers. Experimental results show that compared with a number of state-of-the-art federated learning (FL) algorithms, our proposed EFDLS wins 20 out of 44 standard UCR2018 datasets and achieves the highest mean accuracy (70.14%) on these datasets. In particular, compared with a single-task baseline, EFDLS obtains 32/4/8 regarding \"win\"/\"tie\"/\"lose\" and results in an improvement of approximately 4% in terms of mean accuracy."},"documents":{"kind":"list like","value":["Title: A shift sequence based approach for nurse scheduling and a new benchmark dataset\nYear: 2010\n\nAbstract: This paper investigates an adaptive constructive method for solving nurse rostering problems. The constraints considered in the problems are categorised into three classes: those that are sequence related, those that are nurse schedule related and those that are roster related. We propose a decomposition approach (to construct solutions) that consists of two stages: (1) to construct high quality sequences for nurses by only considering the sequence constraints, and (2) to iteratively construct schedules for nurses and the overall rosters, based on the sequences built and considering the schedule and roster constraints. In the second stage of the schedule construction, nurses are ordered and selected adaptively according to the quality of the schedules they were assigned to in the last iteration. Greedy local search is carried out during and after the roster construction, in order to improve the (partial) rosters built. We show that the local search heuristic during the roster construction can further improve the constructed solutions for the benchmark problems tested.In addition, we introduce new benchmark nurse rostering datasets which are based upon real world data. The data sets represent a variety of real world constraints. The publication of this problem data to the research community is aimed at closing the gap between theory and practice in nurse scheduling research. One of the main objectives is to encourage more research on these data sets.","Title: A constraint programming based column generation approach to nurse rostering problems\nYear: 2012\n\nAbstract: This paper presents our investigations on a hybrid constraint programming based column generation (CP-CG) approach to nurse rostering problems. We present a complete model to formulate all the complex real-world constraints in several benchmark nurse rostering problems. The hybrid CP-CG approach is featured with not only the effective relaxation and optimality reasoning of linear programming but also the powerful expressiveness of constraint programming in modeling the complex logical constraints in nurse rostering problems. In solving the CP pricing subproblem, we propose two strategies to generate promising columns which contribute to the efficiency of the CG procedure. A Depth Bounded Discrepancy Search is employed to obtain diverse columns. A cost threshold is adaptively tightened based on the information collected during the search to generate columns of good quality. Computational experiments on a set of benchmark nurse rostering problems demonstrate a faster convergence by the two strategies and justify the effectiveness and efficiency of the hybrid CP-CG approach.","Title: A simulated annealing based genetic local search algorithm for multi-objective multicast routing problems.\nYear: 2013\n\nAbstract: This paper presents a new hybrid evolutionary algorithm to solve multi-objective multicast routing problems in telecommunication networks. The algorithm combines simulated annealing based strategies and a genetic local search, aiming at a more flexible and effective exploration and exploitation in the search space of the complex problem to find more non-dominated solutions in the Pareto Front. Due to the complex structure of the multicast tree, crossover and mutation operators have been specifically devised concerning the features and constraints in the problem. A new adaptive mutation probability based on simulated annealing is proposed in the hybrid algorithm to adaptively adjust the mutation rate according to the fitness of the new solution against the average quality of the current population during the evolution procedure. Two simulated annealing based search direction tuning strategies are applied to improve the efficiency and effectiveness of the hybrid evolutionary algorithm. Simulations have been carried out on some benchmark multi-objective multicast routing instances and a large amount of random networks with five real world objectives including cost, delay, link utilisations, average delay and delay variation in telecommunication networks. Experimental results demonstrate that both the simulated annealing based strategies and the genetic local search within the proposed multi-objective algorithm, compared with other multi-objective evolutionary algorithms, can efficiently identify high quality non-dominated solution set for multi-objective multicast routing problems and outperform other conventional multi-objective evolutionary algorithms in the literature. © 2013 Springer Science+Business Media New York.","Title: Adaptive automated construction of hybrid heuristics for exam timetabling and graph colouring problems\nYear: 2009\n\nAbstract: In this paper, we present a random iterative graph based hyper-heuristic to produce a collection of heuristic sequences to construct solutions of different quality. These heuristic sequences can be seen as dynamic hybridisations of different graph colouring heuristics that construct solutions step by step. Based on these sequences, we statistically analyse the way in which graph colouring heuristics are automatically hybridised. This, to our knowledge, represents a new direction in hyper-heuristic research. It is observed that spending the search effort on hybridising Largest Weighted Degree with Saturation Degree at the early stage of solution construction tends to generate high quality solutions. Based on these observations, an iterative hybrid approach is developed to adaptively hybridise these two graph colouring heuristics at different stages of solution construction. The overall aim here is to automate the heuristic design process, which draws upon an emerging research theme on developing computer methods to design and adapt heuristics automatically. Experimental results on benchmark exam timetabling and graph colouring problems demonstrate the effectiveness and generality of this adaptive hybrid approach compared with previous methods on automatically generating and adapting heuristics. Indeed, we also show that the approach is competitive with the state of the art human produced methods.","Title: Case-based heuristic selection for timetabling problems\nYear: 2006\n\nAbstract: This paper presents a case-based heuristic selection approach for automated university course and exam timetabling. The method described in this paper is motivated by the goal of developing timetabling systems that are fundamentally more general than the current state of the art. Heuristics that worked well in previous similar situations are memorized in a case base and are retrieved for solving the problem in hand. Knowledge discovery techniques are employed in two distinct scenarios. Firstly, we model the problem and the problem solving situations along with specific heuristics for those problems. Secondly, we refine the case base and discard cases which prove to be non-useful in solving new problems. Experimental results are presented and analyzed. It is shown that case based reasoning can act effectively as an intelligent approach to learn which heuristics work well for particular timetabling situations. We conclude by outlining and discussing potential research issues in this critical area of knowledge discovery for different difficult timetabling problems.","Title: Linear combinations of heuristics for examination timetabling.\nYear: 2012\n\nAbstract: Although they are simple techniques from the early days of timetabling research, graph colouring heuristics are still attracting significant research interest in the timetabling research community. These heuristics involve simple ordering strategies to first select and colour those vertices that are most likely to cause trouble if deferred until later. Most of this work used a single heuristic to measure the difficulty of a vertex. Relatively less attention has been paid to select an appropriate colour for the selected vertex. Some recent work has demonstrated the superiority of combining a number of different heuristics for vertex and colour selection. In this paper, we explore this direction and introduce a new strategy of using linear combinations of heuristics for weighted graphs which model the timetabling problems under consideration. The weights of the heuristic combinations define specific roles that each simple heuristic contributes to the process of ordering vertices. We include specific explanations for the design of our strategy and present the experimental results on a set of benchmark real world examination timetabling problem instances. New best results for several instances have been obtained using this method when compared with other constructive methods applied to this benchmark dataset.","Title: Solving multi-objective multicast routing problems by evolutionary multi-objective simulated annealing algorithms with variable neighbourhoods\nYear: 2011\n\nAbstract: This paper presents the investigation of an evolutionary multi-objective simulated annealing (EMOSA) algorithm with variable neighbourhoods to solve the multi-objective multicast routing problems in telecommunications. The hybrid algorithm aims to carry out a more flexible and adaptive exploration in the complex search space by using features of the variable neighbourhood search to find more non-dominated solutions in the Pareto front. Different neighbourhood strictures have been designed with regard to the set of objectives, aiming to drive the search towards optimising all objectives simultaneously. A large number of simulations have been carried out on benchmark instances and random networks with real world features including cost, delay and link utilisations. Experimental results demonstrate that the proposed EMOSA algorithm with variable neighbourhoods is able to find high-quality non-dominated solutions for the problems tested. In particular, the neighbourhood structures that are specifically designed for each objective significantly improved the performance of the proposed algorithm compared with variants of the algorithm with a single neighbourhood. Journal of the Operational Research Society (2011) 62, 313-325. doi:10.1057/jors.2010.138 Published online 22 September 2010","Title: Analyzing the landscape of a graph based hyper-heuristic for timetabling problems\nYear: 2009\n\nAbstract: Hyper-heuristics can be thought of as \"heuristics to choose heuristics\". They are concerned with adaptively finding solution methods, rather than directly producing a solution for the particular problem at hand. Hence, an important feature of hyper-heuristics is that they operate on a search space of heuristics rather than directly on a search space of problem solutions. A motivating aim is to build systems which are fundamentally more generic than is possible today. Understanding the structure of these heuristic search spaces is therefore, a research direction worth exploring. In this paper, we use the notion of fitness landscapes in the context of constructive hyper-heuristics. We conduct a landscape analysis on a heuristic search space conformed by sequences of graph coloring heuristics for timetabling. Our study reveals that these landscapes have a high level of neutrality and positional bias. Furthermore, although rugged, they have the encouraging feature of a globally convex or big valley structure, which indicates that an optimal solution would not be isolated but surrounded by many local minima. We suggest that using search methodologies that explicitly exploit these features may enhance the performance of constructive hyper-heuristics.","Title: A new model for automated examination timetabling.\nYear: 2012\n\nAbstract: Automated examination timetabling has been addressed by a wide variety of methodologies and techniques over the last ten years or so. Many of the methods in this broad range of approaches have been evaluated on a collection of benchmark instances provided at the University of Toronto in 1996. Whilst the existence of these datasets has provided an invaluable resource for research into examination timetabling, the instances have significant limitations in terms of their relevance to real-world examination timetabling in modern universities. This paper presents a detailed model which draws upon experiences of implementing examination timetabling systems in universities in Europe, Australasia and America.This model represents the problem that was presented in the 2nd International Timetabling Competition (ITC2007). In presenting this detailed new model, this paper describes the examination timetabling track introduced as part of the competition. In addition to the model, the datasets used in the competition are also based on current real-world instances introduced by EventMAP Limited. It is hoped that the interest generated as part of the competition will lead to the development, investigation and application of a host of novel and exciting techniques to address this important real-world search domain. Moreover, the motivating goal of this paper is to close the currently existing gap between theory and practice in examination timetabling by presenting the research community with a rigorous model which represents the complexity of the real-world situation. In this paper we describe the model and its motivations, followed by a full formal definition.","Title: Granular Modelling Of Exam To Slot Allocation\nYear: 2009\n\nAbstract: In this paper, we are introducing a new method of granular exam-to-slot allocation based on the preprocessing of the basic student-exam information into a more abstract (granulated) entity of conflict chains. Since the conflict chains are designed to capture the mutual dependencies between exams, they enable us to reason about the exam-to-slot allocation for all exams in a chain rather than just one exam at-a-time. The initial exam-to-slot allocation, generated through the processing of conflict chains, is then refined by considering the spread of the exams in the examination session so as to minimize the appropriately defined cost function. The granular pre-processing of problem data has been shown to enhance the efficiency of the exam scheduling task and has led to the identification of very competitive exam schedules.","Title: A hybrid algorithm for constrained portfolio selection problems\nYear: 2013\n\nAbstract: Since Markowitz's seminal work on the mean-variance model in modern portfolio theory, many studies have been conducted on computational techniques and recently meta-heuristics for portfolio selection problems. In this work, we propose and investigate a new hybrid algorithm integrating the population based incremental learning and differential evolution algorithms for the portfolio selection problem. We consider the extended mean-variance model with practical trading constraints including the cardinality, floor and ceiling constraints. The proposed hybrid algorithm adopts a partially guided mutation and an elitist strategy to promote the quality of solution. The performance of the proposed hybrid algorithm has been evaluated on the extended benchmark datasets in the OR Library. The computational results demonstrate that the proposed hybrid algorithm is not only effective but also efficient in solving the mean-variance model with real world constraints.","Title: An Adaptive Tie Breaking and Hybridisation Hyper-Heuristic for Exam Timetabling Problems.\nYear: 2011\n\nAbstract: Graph colouring heuristics have long been applied successfully to the exam timetabling problem. Despite the success of a few heuristic ordering criteria developed in the literature, the approaches lack the ability to handle the situations where ties occur. In this paper, we investigate the effectiveness of applying tie breakers to orderings used in graph colouring heuristics. We propose an approach to construct solutions for our problem after defining which heuristics to combine and the amount of each heuristic to be used in the orderings. Heuristic sequences are then adapted to help guide the search to find better quality solutions. We have tested the approach on the Toronto benchmark problems and are able to obtain results which are within the range of the best reported in the literature. In addition, to test the generality of our approach we introduced an exam timetabling instance generator and a new benchmark data set which has a similar format to the Toronto benchmark. The instances generated vary in size and conflict density. The publication of this problem data to the research community is aimed to provide researchers with a data set which covers a full range of conflict densities. Furthermore, it is possible using the instance generator to create random data sets with different characteristics to test the performance of approaches which rely on problem characteristics. We present the first results for the benchmark and the results obtained show that the approach is adaptive to all the problem instances that we address. We also encourage the use of the data set and generator to produce tailored instances and to investigate various methods on them.","Title: A Time Predefined Variable Depth Search for Nurse Rostering\nYear: 2013\n\nAbstract: This paper presents a variable depth search for the nurse rostering problem. The algorithm works by chaining together single neighbourhood swaps into more effective compound moves. It achieves this by using heuristics to decide whether to continue extending a chain and which candidates to examine as the next potential link in the chain. Because end users vary in how long they are willing to wait for solutions, a particular goal of this research was to create an algorithm that accepts a user specified computational time limit and uses it effectively. When compared against previously published approaches the results show that the algorithm is very competitive.","Title: An iterative local search approach based on fitness landscapes analysis for the delay-constrained multicast routing problem\nYear: 2012\n\nAbstract: This paper presents the first fitness landscape analysis on the delay-constrained least-cost multicast routing problem (DCLC-MRP). Although the problem has attracted an increasing research attention over the past decade in telecommunications and operational research, little research has been conducted to analyze the features of its underlying landscape. Two of the most commonly used landscape analysis techniques, the fitness distance correlation analysis and the autocorrelation analysis, have been applied to analyze the global and local landscape features of DCLC-MRPs. A large amount of simulation experiments on a set of problem instances generated based on the benchmark Steiner tree problems in the OR-library reveals that the landscape of the DCLC-MRP is highly instance dependent with different landscape features. Different delay bounds also affect the distribution of solutions in the search space. The autocorrelation analysis on the benchmark instances of different sizes and delay bounds shows the impact of different local search heuristics and neighborhood structures on the fitness distance landscapes of the DCLC-MRP. The delay bound constraint in the DCLC-MRP has shown a great influence on the underlying landscape characteristic of the problem. Based on the fitness landscape analysis, an iterative local search (ILS) approach is proposed in this paper for the first time to tackle the DCLC-MRP. Computational results demonstrate the effectiveness of the proposed ILS algorithm for the problem in comparison with other algorithms in the literature.","Title: A honey-bee mating optimization algorithm for educational timetabling problems.\nYear: 2012\n\nAbstract: In this work, we propose a variant of the honey-bee mating optimization algorithm for solving educational timetabling problems. The honey-bee algorithm is a nature inspired algorithm which simulates the process of real honey-bees mating. The performance of the proposed algorithm is tested over two benchmark problems: exam (Carter's un-capacitated datasets) and course (Socha datasets) timetabling problems. We chose these two datasets as they have been widely studied in the literature and we would also like to evaluate our algorithm across two different, yet related, domains. Results demonstrate that the performance of the honey-bee mating optimization algorithm is comparable with the results of other approaches in the scientific literature. Indeed, the proposed approach obtains best results compared with other approaches on some instances, indicating that the honey-bee mating optimization algorithm is a promising approach in solving educational timetabling problems. (C) 2011 Elsevier B.V. All rights reserved.","Title: Hierarchical Method For Nurse Rostering Based On Granular Pre-Processing Of Constraints\nYear: 2009\n\nAbstract: Nurse Rostering problems represent a subclass of scheduling problems that are hard to solve. Their complexity is due to the large solution spaces and the many objectives and constraints that need to be fulfilled. In this study, we propose a hierarchical method of granulation of problem domain through preprocessing of constraints. A set of zero-cost patterns in the granulated search space provides a basis for the generation of work schedules. Feasible schedules calculated for week 1 are used to define zero-cost shift patterns that can be deployed in week 2. These in turn are used for the generation of feasible schedules for week 2. The process can be applied over the extended time frame. We show that the granulation of the problem description in terms of constraints and scheduling time frames leads to a more manageable computing task.","Title: A Variable Neighborhood Descent Search Algorithm for Delay-Constrained Least-Cost Multicast Routing\nYear: 2009\n\nAbstract: The rapid evolution of real-time multimedia applications requires Quality of Service (QoS) based multicast routing in underlying computer networks. The constrained Steiner Tree, as the underpinning mathematical structure, is a well-known NP-complete problem. In this paper we investigate a variable neighborhood descent (VND) search, a variant of variable neighborhood search, for the delay-constrained least-cost (DCLC) multicast routing problem. The neighborhood structures designed in the VND approaches are based on the idea of path replacement in trees. They are simple, yet effective operators, enabling a flexible search over the solution space of this complex problem with multiple constraints. A large number of simulations demonstrate that our algorithm is highly efficient in solving the DCLC multicast routing problem in terms of the tree cost and execution time. To our knowledge, this is the first study of VND algorithm on the DCLC multicast routing problem. It outperforms other existing algorithms over a range of problem instances.","Title: A Constraint-Directed Local Search Approach To Nurse Rostering Problems\nYear: 2009\n\nAbstract: In this paper, we investigate the hybridization of constraint programming and local search techniques within a large neighbourhood search scheme for solving highly constrained nurse rostering problems. As identified by the research, a crucial part of the large neighbourhood search is the selection of the fragment (neighbourhood, i. e. the set of variables), to be relaxed and re- optimized iteratively. The success of the large neighbourhood search depends on the adequacy of this identified neighbourhood with regard to the problematic part of the solution assignment and the choice of the neighbourhood size. We investigate three strategies to choose the fragment of different sizes within the large neighbourhood search scheme. The first two strategies are tailored concerning the problem properties. The third strategy is more general, using the information of the cost from the soft constraint violations and their propagation as the indicator to choose the variables added into the fragment. The three strategies are analyzed and compared upon a benchmark nurse rostering problem. Promising results demonstrate the possibility of future work in the hybrid approach.","Title: A hybrid model of integer programming and variable neighbourhood search for highly-constrained nurse rostering problems\nYear: 2010\n\nAbstract: This paper presents a hybrid multi-objective model that combines integer programming (IP) and variable neighbourhood search (VNS) to deal with highly-constrained nurse rostering problems in modern hospital environments. An IP is first used to solve the subproblem which includes the full set of hard constraints and a subset of soft constrains. A basic VNS then follows as a postprocessing procedure to further improve the IP’s resulting solutions. The satisfaction of the excluded constraints from the preceding IP model is the major focus of the VNS. Very promising results are reported compared with a commercial genetic algorithm and a hybrid VNS approach on real instances arising in a Dutch hospital. The comparison results demonstrate that our hybrid approach combines the advantages of both the IP and the VNS to beat other approaches in solving this type of problems. We also believe that the proposed methodology can be applied to other resource allocation problems with a large number of constraints.","Title: Evolutionary Ruin And Stochastic Recreate: A Case Study On The Exam Timetabling Problem\nYear: 2012\n\nAbstract: This paper presents a new class of intelligent systems, called Evolutionary Ruin and Stochastic Recreate, that can learn and adapt to the changing enviroment. It improves the original Ruin and Recreate principle's performance by incorporating an Evolutionary Ruin step which implements evolution within a single solution. In the proposed approach, a cycle of Solution Decomposition, Evolutionary Ruin and Stochastic Recreate continues until stopping conditions are reached. The Solution Decomposition step first uses some domain knowledge to break a solution down into its components and assign a score to each. The Evolutionary Ruin step then applies two operators (namely Selection and Mutation) to destroy a certain fraction of the entire solution. After the above steps, an input solution becomes partial and thus the resulting partial solution needs to be repaired. The repair is carried out by using the Stochastic Recreate step to reintroduce the removed items in a specific way (somewhat stochastic in order to have a better chance to jump out of the local optima), and then ask the underlying improvement heuristic whether this move will be accepted. These three steps are executed in sequence until a specific stopping condition is reached. Therefore, optimisation is achieved by solution disruption, iterative improvement and a stochastic constructive repair process performed within. Encouraging experimental results on exam timetabling problems are reported.","Title: A Population Based Incremental Learning for Network Coding Resources Minimization.\nYear: 2011\n\nAbstract: In network coding based multicast, coding operations need to be minimized as they consume computational resources and increase data processing complexity at corresponding nodes in the network. To address the problem, we develop a population based incremental learning algorithm which shows to outperform existing algorithms in terms of both the solution obtained and computational time consumed on networks with various features.","Title: A hybrid scatter search meta-heuristic for delay-constrained multicast routing problems\nYear: 2012\n\nAbstract: This paper investigates the first hybrid scatter search and path relinking meta-heuristic for the Delay-Constrained Least-Cost (DCLC) multicast routing problem. The underpinning mathematic model of the DCLC multicast routing problem is the constrained Steiner tree problem in graphs, a well known NP-complete problem. After combining a path relinking method as the solution combination method in scatter search, we further explore two improvement strategies: tabu search and variable neighborhood search, to intensify the search in the hybrid scatter search algorithm. A large number of simulations on some benchmark instances from the OR-library and a group of random graphs of different characteristics demonstrate that the improvement strategy greatly affects the performance of the proposed scatter search algorithm. The hybrid scatter search algorithm intensified by a variable neighborhood descent search is highly efficient in solving the DCLC multicast routing problem in comparison with other algorithms and heuristics in the literature.","Title: Personnel scheduling: Models and complexity\nYear: 2011\n\nAbstract: Due to its complexity, its challenging features, and its practical relevance, personnel scheduling has been heavily investigated in the last few decades. However, there is a relatively low level of study on models and complexity in these important problems. In this paper, we present mathematical models which cover specific aspects in the personnel scheduling literature. Furthermore, we address complexity issues by identifying polynomial solvable and NP-hard special cases.","Title: A Study Of Cost Effective Scheduling Of Nurses Based On The Domain Transformation Method\nYear: 2013\n\nAbstract: This paper discusses and analyses the tradeoff between the flexibility afforded with greater number of staff and the implied cost of employing extra staff in the context of the nurse-scheduling problem. If the number of staff is constant, our study allows quantification of the degree of pressure put on the staff resulting from the schedules that do not satisfy their preferences for shift allocation. We present a practical approach, based on our domain transformation methodology that achieves good quality schedules without high computational requirements.","Title: A pattern recognition based intelligent search method and two assignment problem case studies\nYear: 2012\n\nAbstract: Numerous papers based on various search methods across a wide variety of applications have appeared in the literature over\n recent years. Most of these methods apply the following same approach to address the problems at hand: at each iteration of\n the search, they first apply their search methods to generate new solutions, then they calculate the objective values (or\n costs) by taking some constraints into account, and finally they use some strategies to determine the acceptance or rejection\n of these solutions based upon the calculated objective values. However, the premise of this paper is that calculating the\n exact objective value of every resulting solution is not a must, particularly for highly constrained problems where such a\n calculation is costly and the feasible regions are small and disconnected. Furthermore, we believe that for newly-generated\n solutions, evaluating the quality purely by their objective values is sometimes not the most efficient approach. In many combinatorial\n problems, there are poor-cost solutions where possibly just one component is misplaced and all others work well. Although\n these poor-cost solutions can be the intermediate states towards the search of a high quality solution, any cost-oriented\n criteria for solution acceptance would deem them as inferior and consequently probably suggest a rejection. To address the\n above issues, we propose a pattern recognition-based framework with the target of designing more intelligent and more flexible\n search systems. The role of pattern recognition is to classify the quality of resulting solutions, based on the solution structure\n rather than the solution cost. Hence, the general contributions of this work are in the line of “insights” and recommendations.\n Two real-world cases of the assignment problem, i.e. the hospital personnel scheduling and educational timetabling, are used\n as the case studies. For each case, we apply neural networks as the tool for pattern recognition. In addition, we present\n our theoretical and experimental results in terms of runtime speedup.","Title: A graph coloring constructive hyper-heuristic for examination timetabling problems\nYear: 2012\n\nAbstract: In this work we investigate a new graph coloring constructive hyper-heuristic for solving examination timetabling problems. We utilize the hierarchical hybridizations of four low level graph coloring heuristics, these being largest degree, saturation degree, largest colored degree and largest enrollment. These are hybridized to produce four ordered lists. For each list, the difficulty index of scheduling the first exam is calculated by considering its order in all lists to obtain a combined evaluation of its difficulty. The most difficult exam to be scheduled is scheduled first (i.e. the one with the minimum difficulty index). To improve the effectiveness of timeslot selection, a roulette wheel selection mechanism is included in the algorithm to probabilistically select an appropriate timeslot for the chosen exam. We test our proposed approach on the most widely used un-capacitated Carter benchmarks and also on the recently introduced examination timetable dataset from the 2007 International Timetabling Competition. Compared against other methodologies, our results demonstrate that the graph coloring constructive hyper-heuristic produces good results and outperforms other approaches on some of the benchmark instances.","Title: Particle swarm optimization for the Steiner tree in graph and delay-constrained multicast routing problems\nYear: 2013\n\nAbstract: This paper presents the first investigation on applying a particle swarm optimization (PSO) algorithm to both the Steiner tree problem and the delay constrained multicast routing problem. Steiner tree problems, being the underlining models of many applications, have received significant research attention within the meta-heuristics community. The literature on the application of meta-heuristics to multicast routing problems is less extensive but includes several promising approaches. Many interesting research issues still remain to be investigated, for example, the inclusion of different constraints, such as delay bounds, when finding multicast trees with minimum cost. In this paper, we develop a novel PSO algorithm based on the jumping PSO (JPSO) algorithm recently developed by Moreno-Perez et al. (Proc. of the 7th Metaheuristics International Conference, 2007), and also propose two novel local search heuristics within our JPSO framework. A path replacement operator has been used in particle moves to improve the positions of the particle with regard to the structure of the tree. We test the performance of our JPSO algorithm, and the effect of the integrated local search heuristics by an extensive set of experiments on multicast routing benchmark problems and Steiner tree problems from the OR library. The experimental results show the superior performance of the proposed JPSO algorithm over a number of other state-of-the-art approaches.","Title: A scatter search methodology for the nurse rostering problem\nYear: 2010\n\nAbstract: The benefits of automating the nurse scheduling process in hospitals include reducing the planning workload and associated costs and being able to create higher quality and more flexible schedules. This has become more important recently in order to retain nurses and to attract more people into the profession. Better quality rosters also reduce fatigue and stress due to overwork and poor scheduling and help to maximise the use of leisure time by satisfying more requests. A more contented workforce will lead to higher productivity, increased quality of patient service and a better level of healthcare. This paper presents a scatter search approach for the problem of automatically creating nurse rosters. Scatter search is an evolutionary algorithm, which has been successfully applied across a number of problem domains. To adapt and apply scatter search to nurse rostering, it was necessary to develop novel implementations of some of scatter search's subroutines. The algorithm was then tested on publicly available real-world benchmark instances and compared against previously published approaches. The results show the proposed algorithm is a robust and effective method on a wide variety of real-world instances. Journal of the Operational Research Society (2010) 61, 1667-1679. doi: 10.1057/jors.2009.118 Published online 4 November 2009","Title: Tabu assisted guided local search approaches for freight service network design\nYear: 2012\n\nAbstract: The service network design problem (SNDP) is a core problem in freight transportation. It involves the determination of the most cost-effective transportation network and the characteristics of the corresponding services, subject to various constraints. The scale of the problem in real-world applications is usually very large, especially when the network contains both the geographical information and the temporal constraints which are necessary for modelling multiple service-classes and dynamic events. The development of time-efficient algorithms for this problem is, therefore, crucial for successful real-world applications. Earlier research indicated that guided local search (GLS) was a promising solution method for this problem. One of the advantages of GLS is that it makes use of both the information collected during the search as well as any special structures which are present in solutions. Building upon earlier research, this paper carries out in-depth investigations into several mechanisms that could potentially speed up the GLS algorithm for the SNDP. Specifically, the mechanisms that we have looked at in this paper include a tabu list (as used by tabu search), short-term memory, and an aspiration criterion. An efficient hybrid algorithm for the SNDP is then proposed, based upon the results of these experiments. The algorithm combines a tabu list within a multi-start GLS approach, with an efficient feasibility-repairing heuristic. Experimental tests on a set of 24 well-known service network design benchmark instances have shown that the proposed algorithm is superior to a previously proposed tabu search method, reducing the computation time by over a third. In addition, we also show that far better results can be obtained when a faster linear program solver is adopted for the sub-problem solution. The contribution of this paper is an efficient algorithm, along with detailed analyses of effective mechanisms which can help to increase the speed of the GLS algorithm for the SNDP.","Title: A hybrid heuristic ordering and variable neighbourhood search for the nurse rostering problem\nYear: 2008\n\nAbstract: This paper is concerned with the development of intelligent decision support methodologies for nurse rostering problems in large modern hospital environments. We present an approach which hybridises heuristic ordering with variable neighbourhood search. We show that the search can be extended and the solution quality can be significantly improved by the careful combination and repeated use of heuristic ordering, variable neighbourhood search and back-tracking. The amount of computational time that is allowed plays a significant role and we analyse and discuss this. The algorithms are evaluated against a commercial Genetic Algorithm on commercial data. We demonstrate that this methodology can significantly outperform the commercial algorithm. This paper is one of the few in the scientific nurse rostering literature which deal with commercial data and which compare against a commercially implemented algorithm.","Title: Integrating neural networks and logistic regression to underpin hyper-heuristic search\nYear: 2011\n\nAbstract: A hyper-heuristic often represents a heuristic search method that operates over a space of heuristic rules. It can be thought of as a high level search methodology to choose lower level heuristics. Nearly 200 papers on hyper-heuristics have recently appeared in the literature. A common theme in this body of literature is an attempt to solve the problems in hand in the following way: at each decision point, first employ the chosen heuristic(s) to generate a solution, then calculate the objective value of the solution by taking into account all the constraints involved. However, empirical studies from our previous research have revealed that, under many circumstances, there is no need to carry out this costly 2-stage determination and evaluation at all times. This is because many problems in the real world are highly constrained with the characteristic that the regions of feasible solutions are rather scattered and small. Motivated by this observation and with the aim of making the hyper-heuristic search more efficient and more effective, this paper investigates two fundamentally different data mining techniques, namely artificial neural networks and binary logistic regression. By learning from examples, these techniques are able to find global patterns hidden in large data sets and achieve the goal of appropriately classifying the data. With the trained classification rules or estimated parameters, the performance (i.e. the worth of acceptance or rejection) of a resulting solution during the hyper-heuristic search can be predicted without the need to undertake the computationally expensive 2-stage of determination and calculation. We evaluate our approaches on the solutions (i.e. the sequences of heuristic rules) generated by a graph-based hyper-heuristic proposed for exam timetabling problems. Time complexity analysis demonstrates that the neural network and the logistic regression method can speed up the search significantly. We believe that our work sheds light on the development of more advanced knowledge-based decision support systems.","Title: A compact genetic algorithm for the network coding based resource minimization problem\nYear: 2012\n\nAbstract: In network coding based data transmission, intermediate nodes in the network are allowed to perform mathematical operations to recombine (code) data packets received from different incoming links. Such coding operations incur additional computational overhead and consume public resources such as buffering and computational resource within the network. Therefore, the amount of coding operations is expected to be minimized so that more public resources are left for other network applications.In this paper, we investigate the newly emerged problem of minimizing the amount of coding operations required in network coding based multicast. To this end, we develop the first elitism-based compact genetic algorithm (cGA) to the problem concerned, with three extensions to improve the algorithm performance. First, we make use of an all-one vector to guide the probability vector (PV) in cGA towards feasible individuals. Second, we embed a PV restart scheme into the cGA where the PV is reset to a previously recorded value when no improvement can be obtained within a given number of consecutive generations. Third, we design a problem-specific local search operator that improves each feasible solution obtained by the cGA. Experimental results demonstrate that all the adopted improvement schemes contribute to an enhanced performance of our cGA. In addition, the proposed cGA is superior to some existing evolutionary algorithms in terms of both exploration and exploitation simultaneously in reduced computational time.","Title: Case-Based Reasoning in Course Timetabling: An Attribute Graph Approach\nYear: 2001\n\nAbstract: An earlier Case-based Reasoning (CBR) approach developed by the authors for educational course timetabling problems employed structured cases to represent the complex relationships between courses. The retrieval searches for structurally similar cases in the case base. In this paper, the approach is further developed to solve a wider range of problems. We also attempt to retrieve those cases that have common similar structures with some differences. Costs that are assigned to these differences have an input upon the similarity measure. A large number of experiments are performed consisting of different randomly produced timetabling problems and the results presented here strongly indicate that a CBR approach could provide a significant step forward in the development of automated systems to solve difficult timetabling problems. They show that using relatively little effort, we can retrieve these structurally similar cases to provide high quality timetables for new timetabling problems.","Title: A Pareto-based search methodology for multi-objective nurse scheduling.\nYear: 2012\n\nAbstract: In this paper, we propose a search technique for nurse scheduling, which deals with it as a multi-objective problem. For each nurse, we first randomly generate a set of legal shift patterns which satisfy all shift-related hard constraints. We then employ an adaptive heuristic to quickly find a solution with the least number of violations on the coverage-related hard constraint by assigning one of the available shift patterns of each nurse. Next, we apply a coverage repairing procedure to make the resulting solution feasible, by adding/removing any under-covered/over-covered shifts. Finally, to satisfy the soft constraints (or preferences), we present a simulated annealing based search method with the following two options: one with a weighted-sum evaluation function which encourages moves towards users’ predefined preferences, and another one with a domination-based evaluation function which encourages moves towards a more diversified approximated Pareto set. Computational results demonstrate that the proposed technique is applicable to modern hospital environments.","Title: Hybrid variable neighbourhood approaches to university exam timetabling\nYear: 2010\n\nAbstract: In this paper, we investigate variable neighbourhood search (VNS) approaches for the university examination timetabling problem. In addition to a basic VNS method, we introduce variants of the technique with different initialisation methods including a biased VNS and its hybridisation with a Genetic Algorithm. A number of different neighbourhood structures are analysed. It is demonstrated that the proposed technique is able to produce high quality solutions across a wide range of benchmark problem instances. In particular, we demonstrate that the Genetic Algorithm, which intelligently selects appropriate neighbourhoods to use within the biased VNS, produces the best known results in the literature, in terms of solution quality, on some of the benchmark instances. However, it requires relatively large amount of computational time. Possible extensions to this overall approach are also discussed.","Title: Knowledge Discovery in a Hyper-heuristic for Course Timetabling Using Case-Based Reasoning\nYear: 2002\n\nAbstract: This paper presents a new hyper-heuristic method using Case-Based Reasoning (CBR) for solving course timetabling problems. The term hyper-heuristics has recently been employed to refer to \"heuristics that choose heuristics\" rather than heuristics that operate directly on given problems. One of the overriding motivations of hyper-heuristic methods is the attempt to develop techniques that can operate with greater generality than is currently possible. The basic idea behind this is that we maintain a case base of information about the most successful heuristics for a range of previous timetabling problems to predict the best heuristic for the new problem in hand using the previous knowledge. Knowledge discovery techniques axe used to carry out the training on the CBR system to improve the system performance on the prediction. Initial results presented in this paper are good and we conclude by discussing the considerable promise for future work in this area.","Title: Multiple-Retrieval Case-Based Reasoning for Course Timetabling Problems\nYear: 2006\n\nAbstract: The structured representation of cases by attribute graphs in a Case-Based Reasoning (CBR) system for course timetabling has been the subject of previous research by the authors. In that system, the case base is organised as a decision tree and the retrieval process chooses those cases which are sub attribute graph isomorphic to the new case. The drawback of that approach is that it is not suitable for solving large problems. This paper presents a multiple-retrieval approach that partitions a large problem into small solvable sub-problems by recursively inputting the unsolved part of the graph into the decision tree for retrieval. The adaptation combines the retrieved partial solutions of all the partitioned sub-problems and employs a graph heuristic method to construct the whole solution for the new case. We present a methodology which is not dependant upon problem specific information and which, as such, represents an approach which underpins the goal of building more general timetabling systems. We explore the question of whether this multiple-retrieval CBR could be an effective initialisation method for local search methods such as Hill Climbing, Tabu Search and Simulated Annealing. Significant results are obtained from a wide range of experiments. An evaluation of the CBR system is presented and the impact of the approach on timetabling research is discussed. We see that the approach does indeed represent an effective initialisation method for these approaches.","Title: Analysis Of Backtracking In University Examination Scheduling\nYear: 2013\n\nAbstract: Simulation modelling of the initial assignments of exams to time-slots provides an alternative approach to the establishment of a set of feasible solutions that are subsequently optimized. In this research, we analyze two backtracking strategies for reassigning exams after the initial allocation of exams to time-slots. We propose two approaches for backtracking, BT1 and BT2. The study indicates that backtracking is an effective approach for improving the quality of the examination schedule where BT2 has outperformed BT1 in a number of cases.","Title: Investigating a hybrid metaheuristic for job shop rescheduling\nYear: 2007\n\nAbstract: Previous research has shown that artificial immune systems can be used to produce robust schedules in a manufacturing environment. The main goal is to develop building blocks (antibodies) of partial schedules that can be used to construct backup solutions (antigens) when disturbances occur during production. The building blocks are created based upon underpinning ideas from artificial immune systems and evolved using a genetic algorithm (Phase I). Each partial schedule (antibody) is assigned a fitness value and the best partial schedules are selected to be converted into complete schedules (antigens). We further investigate whether simulated annealing and the great deluge algorithm can improve the results when hybridised with our artificial immune system (Phase II). We use ten fixed solutions as our target and measure how well we cover these specific scenarios.","Title: Roulette Wheel Graph Colouring for Solving Examination Timetabling Problems\nYear: 2009\n\nAbstract: This work presents a simple graph based heuristic that employs a roulette wheel selection mechanism for solving exam timetabling problems. We arrange exams in non-increasing order of the number of conflicts (degree) that they have with other exams. The difficulty of each exam to be scheduled is estimated based on the degree of exams in conflict. The degree determines the size of a segment in a roulette wheel, with a larger degree giving a larger segment. The roulette wheel selection mechanism selects an exam if the generated random number falls within the exam's segment. This overcomes the problem of repeatedly choosing and scheduling the same sequence of exams. We utilise the proposed Roulette Wheel Graph Colouring heuristic on the un-capacitated Carter's benchmark datasets. Results showed that this simple heuristic is capable of producing feasible solutions for all 13 instances.","Title: A Hybrid Constraint Programming Approach for Nurse Rostering Problems\nYear: 2008\n\nAbstract: Due to the complexity of nurse rostering problems (NRPs), Constraint Programming (CP) approaches on their own have shown to be ineffective in solving these highly constrained problems. We investigate a two-stage hybrid CP approach on real world benchmark NRPs. In the first stage, a constraint satisfaction model is used to generate weekly rosters consist of high quality shift sequences satisfying a subset of constraints. An iterative forward search is then adapted to extend them to build complete feasible solutions. Variable and value selection heuristics are employed to improve the efficiency. In the second stage, a simple Variable Neighborhood Search is used to quickly improve the solution obtained. The basic idea of the hybrid approach is based on the observations that high quality nurse rosters consist of high quality shift sequences. By decomposing the problems into solvable sub-problems for CP, the search space of the original problems are significantly reduced. The results on benchmark problems demonstrate the efficiency of this hybrid CP approach when compared to the state-of-the-art approaches in the literature.","Title: Adaptive selection of heuristics for assigning time slots and rooms in exam timetables\nYear: 2013\n\nAbstract: This paper presents an iterative adaptive approach which hybridises bin packing heuristics to assign exams to time slots and rooms. The approach combines a graph-colouring heuristic, to select an exam in every iteration, with bin-packing heuristics to automate the process of time slot and room allocation for exam timetabling problems. We start by analysing the quality of the solutions obtained by using one heuristic at a time. Depending on the individual performance of each heuristic, a random iterative hyper-heuristic is used to randomly hybridise the heuristics and produce a collection of heuristic sequences to construct solutions with different quality. Based on these sequences, we analyse the way in which the bin packing heuristics are automatically hybridised. It is observed that the performance of the heuristics used varies depending on the problem. Based on these observations, an iterative hybrid approach is developed to adaptively choose and hybridise the heuristics during solution construction. The overall aim here is to automate the heuristic design process, which draws upon an emerging research theme which is concerned with developing methods to design and adapt heuristics automatically. The approach is tested on the exam timetabling track of the second International Timetabling Competition, to evaluate its ability to generalise on instances with different features. The hyper-heuristic with low-level graph-colouring and bin-packing heuristics approach was found to generalise well over all the problem instances and performed comparably to the state of the art approaches.","Title: Hybridizations within a graph-based hyper-heuristic framework for university timetabling problems\nYear: 2009\n\nAbstract: A significant body of literature has explored various research directions in hyper-heuristics (which can be thought as heuristics to choose heuristics). In this paper we define a graph based hyper-heuristic (GHH) framework and compare the performance of a number of local search based searching algorithms as the high level heuristics. They are used to search upon permutations of low level graph heuristics rather than solutions within the GHH framework. We also investigate efficient hybridisations between the GHH and local search methods. Aiming at gaining an in-depth understanding on this new technique, we address and discuss the fundamental issues concerning the neighborhood structures, the characteristics of the two search spaces (namely the search spaces of the graph heuristics and the actual solutions). Issues of exploring by the high level search and exploiting by the local search within the hy- brid GHH are also addressed. These, to our knowledge, are entirely novel directions in hyper-heuristics. The comparisons among different high level heuristics within the unified framework suggest that the role high level search play is to explore as wide search space as possible within a limited time using simple and iterative methods. The efficient hybridisations within the GHH obtained competitive results compared with the best published results for both benchmark course and exam timetabling problems, demonstrating its efficiency and generality. Possible extensions upon this simple yet general graph based hyper-heuristic are also provided.","Title: Solving a practical examination timetabling problem: a case study\nYear: 2007\n\nAbstract: This paper presents a Greedy-Least Saturation Degree (G-LSD) heuristic (which is an adaptation of the least saturation degree heuristic) to solve a real-world examination timetabling problem at the University Kebangsaan, Malaysia. We utilise a new objective function that was proposed in our previous work to evaluate the quality of the timetable. The objective function considers both timeslots and days in assigning exams to timeslots, where higher priority is given to minimise students having consecutive exams on the same day. The objective also tries to spread exams throughout the examination period. This heuristic has the potential to be used for the benchmark examination datasets (e.g. the Carter datasets) as well as other real world problems. Computational results are presented.","Title: A nondominated sorting genetic algorithm for bi-objective network coding based multicast routing problems\nYear: 2013\n\nAbstract: Network coding is a new communication technique that generalizes routing, where, instead of simply forwarding the packets they receive, intermediate nodes are allowed to recombine (code) together some of the data packets received from different incoming links if necessary. By doing so, the maximum information flow in a network can always be achieved. However, performing coding operations (i.e. recombining data packets) incur computational overhead and delay of data processing at the corresponding nodes. In this paper, we investigate the optimization of the network coding based multicast routing problem with respect to two widely considered objectives, i.e. the cost and the delay. In general, reducing cost can result into a cheaper multicast solution for network service providers, while decreasing delay improves the service quality for users. Hence we model the problem as a bi-objective optimization problem to minimize the total cost and the maximum transmission delay of a multicast. This bi-objective optimization problem has not been considered in the literature. We adapt the Elitist Nondominated Sorting Genetic Algorithm (NSGA-II) for the new problem by introducing two adjustments. As there are many infeasible solutions in the search space, the first adjustment is an initialization scheme to generate a population of feasible and diversified solutions. These initial solutions help to guide the search towards the Pareto-optimal front. In addition, the original NSGA-II is very likely to produce a number of solutions with identical objective values at each generation, which may seriously deteriorate the level of diversity and the optimization performance. The second adjustment is an individual delegate scheme where, among those solutions with identical objective values, only one of them is retained in the population while the others are deleted. Experimental results reveal that each adopted adjustment contributes to the adaptation of NSGA-II for the problem concerned. Moreover, the adjusted NSGA-II outperforms a number of state-of-the-art multiobjective evolutionary algorithms with respect to the quality of the obtained nondominated solutions in the conducted experiments.","Title: A graph-based hyper-heuristic for educational timetabling problems\nYear: 2007\n\nAbstract: This paper presents an investigation of a simple generic hyper-heuristic approach upon a set of widely used constructive heuristics (graph coloring heuristics) in timetabling. Within the hyper-heuristic framework, a tabu search approach is employed to search for permutations of graph heuristics which are used for constructing timetables in exam and course timetabling problems. This underpins a multi-stage hyper-heuristic where the tabu search employs permutations upon a different number of graph heuristics in two stages. We study this graph-based hyper-heuristic approach within the context of exploring fundamental issues concerning the search space of the hyper-heuristic (the heuristic space) and the solution space. Such issues have not been addressed in other hyper-heuristic research. These approaches are tested on both exam and course benchmark timetabling problems and are compared with the fine-tuned bespoke state-of-the-art approaches. The results are within the range of the best results reported in the literature. The approach described here represents a significantly more generally applicable approach than the current state of the art in the literature. Future work will extend this hyper-heuristic framework by employing methodologies which are applicable on a wider range of timetabling and scheduling problems.","Title: A population based incremental learning for delay constrained network coding resource minimization\nYear: 2011\n\nAbstract: In network coding based multicast, coding operations are expected to be minimized as they not only incur additional computational cost at corresponding nodes in network but also increase data transmission delay. On the other hand, delay constraint must be concerned particularly in delay sensitive applications, e.g. video conferencing. In this paper, we study the problem of minimizing the amount of coding operations required while meeting the end-to-end delay constraint in network coding based multicast. A population based incremental learning (PBIL) algorithm is developed, where a group of best so far individuals, rather than a single one, is maintained and used to update the probability vector, which enhances the global search capability of the algorithm. Simulation results demonstrate the effectiveness of our PBIL.","Title: Setting the Research Agenda in Automated Timetabling: The Second International Timetabling Competition\nYear: 2010\n\nAbstract: The Second International Timetabling Competition (TTC2007) opened in August 2007. Building on the success of the first competition in 2002, this sequel aimed to further develop research activity in the area of educational timetabling. The broad aim of the competition was to create better understanding between researchers and practitioners by allowing emerging techniques to be developed and tested on real-world models of timetabling problems. To support this, a primary goal was to provide researchers with models of problems faced by practitioners through incorporating a significant number of real-world constraints. Another objective of the competition was to stimulate debate within the widening timetabling research community. The competition was divided into three tracks to reflect the important variations that exist in educational timetabling within higher education. Because these formulations incorporate an increased number of “real-world” issues, it is anticipated that the competition will now set the research agenda within the field. After finishing in January 2008, final results were made available in May 2008. Along with background to the competition, the competition tracks are described here along with a brief overview of the techniques used by the competition winners.","Title: A Task Based Approach For A Real-World Commodity Routing Problem\nYear: 2013\n\nAbstract: In this paper, a real world short-haul commodity routing problem is presented. This problem shares several similarities with vehicle routing problem with time windows (VRPTW) and the service network design problem (SNDP), but also has its own specific structures that do not exist in VRPTW or SNDP. A task based formulation is developed for this problem and a variable neighbourhood search metaheuristic approach is proposed, resulting in a visible improvement over the original routing plans according to experimental tests over three real-life instances. Apart from introducing a new real-world commodity routing problem, another main contribution of this paper is a task based formulation that allows commodity flows being considered as nodes in a routing network. Thus algorithms that were designed for VRPTW or SDVRP can also possibly be adapted to solve this commodity flow problem.","Title: Supply chain coordination with dual procurement sources via real-option contract\nYear: 2015\n\nAbstract: We explore the manufacturer's optimal procurement strategy under stochastic demand.The manufacturer purchases from the supplier and the existing spot markets.The manufacturer maneuvers the real-option to coordinate the supply chain.Effects of risks in the spot market on market equilibrium are derived. In a two-stage supply chain with a supplier and a manufacturer, the manufacturer can purchase a product either from the supplier or in the spot market. The spot market, however, inevitably involves price fluctuation risk and supply risk. Assuming that the manufacturer is the leader in a procurement game and offers a real-option contract to the supplier, we study the manufacturer's optimal mixed procurement strategy that integrates the use of the real-option contract and the spot market. Moreover, we analyze the effects of the price risk and the supply risk in the spot market on market equilibrium. We show that using the real-option contract mechanism improves the overall expected profit of a supply chain and guarantees supply chain coordination in the presence of the spot market. The results also demonstrate that the price risk and the supply risk in the spot market adversely affect the manufacturer's expected profit. On the contrary, these two risks bring benefits to the supplier.","Title: A dynamic multiarmed bandit-gene expression programming hyper-heuristic for combinatorial optimization problems.\nYear: 2015\n\nAbstract: Hyper-heuristics are search methodologies that aim to provide high-quality solutions across a wide variety of problem domains, rather than developing tailor-made methodologies for each problem instance/domain. A traditional hyper-heuristic framework has two levels, namely, the high level strategy (heuristic selection mechanism and the acceptance criterion) and low level heuristics (a set of problem specific heuristics). Due to the different landscape structures of different problem instances, the high level strategy plays an important role in the design of a hyper-heuristic framework. In this paper, we propose a new high level strategy for a hyper-heuristic framework. The proposed high-level strategy utilizes a dynamic multiarmed bandit-extreme value-based reward as an online heuristic selection mechanism to select the appropriate heuristic to be applied at each iteration. In addition, we propose a gene expression programming framework to automatically generate the acceptance criterion for each problem instance, instead of using human-designed criteria. Two well-known, and very different, combinatorial optimization problems, one static (exam timetabling) and one dynamic (dynamic vehicle routing) are used to demonstrate the generality of the proposed framework. Compared with state-of-the-art hyper-heuristics and other bespoke methods, empirical results demonstrate that the proposed framework is able to generalize well across both domains. We obtain competitive, if not better results, when compared to the best known results obtained from other methods that have been presented in the scientific literature. We also compare our approach against the recently released hyper-heuristic competition test suite. We again demonstrate the generality of our approach when we compare against other methods that have utilized the same six benchmark datasets from this test suite.","Title: A learning-guided multi-objective evolutionary algorithm for constrained portfolio optimization.\nYear: 2014\n\nAbstract: Portfolio optimization involves the optimal assignment of limited capital to different available financial assets to achieve a reasonable trade-off between profit and risk objectives. In this paper, we studied the extended Markowitz's mean-variance portfolio optimization model. We considered the cardinality, quantity, pre-assignment and round lot constraints in the extended model. These four real-world constraints limit the number of assets in a portfolio, restrict the minimum and maximum proportions of assets held in the portfolio, require some specific assets to be included in the portfolio and require to invest the assets in units of a certain size respectively. An efficient learning-guided hybrid multi-objective evolutionary algorithm is proposed to solve the constrained portfolio optimization problem in the extended mean-variance framework. A learning-guided solution generation strategy is incorporated into the multi-objective optimization process to promote the efficient convergence by guiding the evolutionary search towards the promising regions of the search space. The proposed algorithm is compared against four existing state-of- the-art multi-objective evolutionary algorithms, namely Non-dominated Sorting Genetic Algorithm ( NSGA-II), Strength Pareto Evolutionary Algorithm (SPEA-2), Pareto Envelope-based Selection Algorithm (PESA-II) and Pareto Archived Evolution Strategy (PAES). Computational results are reported for publicly available OR-library datasets from seven market indices involving up to 1318 assets. Experimental results on the constrained portfolio optimization problem demonstrate that the proposed algorithm significantly outperforms the four well-known multi-objective evolutionary algorithms with respect to the quality of obtained efficient frontier in the conducted experiments. (C) 2014 The Authors. Published by Elsevier B.V.","Title: Search with evolutionary ruin and stochastic rebuild: A theoretic framework and a case study on exam timetabling.\nYear: 2015\n\nAbstract: •This paper presents a new search method which tries to learn and adapt to the changing environments during the search.•It improves the original R&R idea by implementing a phase of Evolutionary Ruin to mimic an evolution within single solutions.•It achieves optimisation by an iterative process of component evaluation, solution disruption and stochastic constructive repair.•It presents a formal framework and implements a Markov chain analysis on some theoretical properties of the approach.•Experimental results on exam timetabling benchmark problems have demonstrated the strength of the approach.","Title: A two-stage stochastic mixed-integer program modelling and hybrid solution approach to portfolio selection problems.\nYear: 2014\n\nAbstract: In this paper, we investigate a multi-period portfolio selection problem with a comprehensive set of real-world trading constraints as well as market random uncertainty in terms of asset prices. We formulate the problem into a two-stage stochastic mixed-integer program (SMIP) with recourse. The set of constraints is modelled as mixed-integer program, while a set of decision variables to rebalance the portfolio in multiple periods is explicitly introduced as the recourse variables in the second stage of stochastic program. Although the combination of stochastic program and mixed-integer program leads to computational challenges in finding solutions to the problem, the proposed SMIP model provides an insightful and flexible description of the problem. The model also enables the investors to make decisions subject to real-world trading constraints and market uncertainty.","Title: Network flow models for intraday personnel scheduling problems.\nYear: 2014\n\nAbstract: Personnel scheduling problems can be decomposed into two stages. In the first stage for each employee the working days have to be fixed. In the second stage for each day of the planning period an intraday scheduling problem has to be solved. It consists of the assignment of shifts to the employees who have to work on the day and for each working period of an employee a task assignment such that the demand of all tasks for personnel is covered. In Robinson et al. (Burke and Trick (Eds.), Proceedings of the 5th International Conference on the Practice and Theory of Automated Timetabling, 18th August–20th August 2004, Pittsburgh, PA, USA, pp. 561–566, ), the intraday problem has been formulated as a maximum flow problem. The assumptions are that, employees are qualified for all tasks, their shifts are given, and they are allowed to change tasks during the day.In this work, we extend the network flow model to cover the case where not all employees are qualified to perform all tasks. The model is further extended to be able to calculate shifts of employees for the given day, assuming that an earliest starting time, a latest finishing time, and a minimal working time are given. Labour cost can be also taken into account by solving a minimum cost network flow problem.","Title: Adaptive selection of heuristics for improving exam timetables.\nYear: 2014\n\nAbstract: This paper presents a hyper-heuristic approach which hybridises low-level heuristic moves to improve timetables. Exams which cause a soft-constraint violation in the timetable are ordered and rescheduled to produce a better timetable. It is observed that both the order in which exams are rescheduled and the heuristic moves used to reschedule the exams and improve the timetable affect the quality of the solution produced. After testing different combinations in a hybrid hyper-heuristic approach, the Kempe chain move heuristic and time-slot swapping heuristic proved to be the best heuristic moves to use in a hybridisation. Similarly, it was shown that ordering the exams using Saturation Degree and breaking any ties using Largest Weighted Degree produce the best results. Based on these observations, a methodology is developed to adaptively hybridise the Kempe chain move and timeslot swapping heuristics in two stages. In the first stage, random heuristic sequences are generated and automatically analysed. The heuristics repeated in the best sequences are fixed while the rest are kept empty. In the second stage, sequences are generated by randomly assigning heuristics to the empty positions in an attempt to find the best heuristic sequence. Finally, the generated sequences are applied to the problem. The approach is tested on the Toronto benchmark and the exam timetabling track of the second International Timetabling Competition, to evaluate its generality. The hyper-heuristic with low-level improvement heuristics approach was found to generalise well over the two different datasets and performed comparably to the state of the art approaches.","Title: Hybridising heuristics within an estimation distribution algorithm for examination timetabling\nYear: 2015\n\nAbstract: This paper presents a hybrid hyper-heuristic approach based on estimation distribution algorithms. The main motivation is to raise the level of generality for search methodologies. The objective of the hyper-heuristic is to produce solutions of acceptable quality for a number of optimisation problems. In this work, we demonstrate the generality through experimental results for different variants of exam timetabling problems. The hyper-heuristic represents an automated constructive method that searches for heuristic choices from a given set of low-level heuristics based only on non-domain-specific knowledge. The high-level search methodology is based on a simple estimation distribution algorithm. It is capable of guiding the search to select appropriate heuristics in different problem solving situations. The probability distribution of low-level heuristics at different stages of solution construction can be used to measure their effectiveness and possibly help to facilitate more intelligent hyper-heuristic search methods.","Title: On minimizing coding operations in network coding based multicast: an evolutionary algorithm\nYear: 2014\n\nAbstract: In telecommunications networks, to enable a valid data transmission based on network coding, any intermediate node within a given network is allowed, if necessary, to perform coding operations. The more coding operations needed, the more coding resources consumed and thus the more computational overhead and transmission delay incurred. This paper investigates an efficient evolutionary algorithm to minimize the amount of coding operations required in network coding based multicast. Based on genetic algorithms, we adapt two extensions in the proposed evolutionary algorithm, namely a new crossover operator and a neighbourhood search operator, to effectively solve the highly complex problem being concerned. The new crossover is based on logic OR operations to each pair of selected parent individuals, and the resulting offspring are more likely to become feasible. The aim of this operator is to intensify the search in regions with plenty of feasible individuals. The neighbourhood search consists of two moves which are based on greedy link removal and path reconstruction, respectively. Due to the specific problem feature, it is possible that each feasible individual corresponds to a number of, rather than a single, valid network coding based routing subgraphs. The neighbourhood search is applied to each feasible individual to find a better routing subgraph that consumes less coding resource. This operator not only improves solution quality but also accelerates the convergence. Experiments have been carried out on a number of fixed and randomly generated benchmark networks. The results demonstrate that with the two extensions, our evolutionary algorithm is effective and outperforms a number of state-of-the-art algorithms in terms of the ability of finding optimal solutions.","Title: A path-oriented encoding evolutionary algorithm for network coding resource minimization.\nYear: 2014\n\nAbstract: Network coding is an emerging telecommunication technique, where any intermediate node is allowed to recombine incoming data if necessary. This technique helps to increase the throughput, however, very likely at the cost of huge amount of computational overhead, due to the packet recombination performed (ie coding operations). Hence, it is of practical importance to reduce coding operations while retaining the benefits that network coding brings to us. In this paper, we propose a novel evolutionary algorithm (EA) to minimize the amount of coding operations involved. Different from the state-of-the-art EAs which all use binary encodings for the problem, our EA is based on path-oriented encoding. In this new encoding scheme, each chromosome is represented by a union of paths originating from the source and terminating at one of the receivers. Employing path-oriented encoding leads to a search space where all solutions are feasible, which fundamentally facilitates more efficient search of EAs. Based on the new encoding, we develop three basic operators, that is, initialization, crossover and mutation. In addition, we design a local search operator to improve the solution quality and hence the performance of our EA. The simulation results demonstrate that our EA significantly outperforms the state-of-the-art algorithms in terms of global exploration and computational time.","Title: A Population-Based Incremental Learning Method for Constrained Portfolio Optimisation\nYear: 2014\n\nAbstract: This paper investigates a hybrid algorithm which utilizes exact and heuristic methods to optimise asset selection and capital allocation in portfolio optimisation. The proposed method is composed of a customised population based incremental learning procedure and a mathematical programming application. It is based on the standard Markowitz model with additional practical constraints such as cardinality on the number of assets and quantity of the allocated capital. Computational experiments have been conducted and analysis has demonstrated the performance and effectiveness of the proposed approach.","Title: Vehicle Routing in a Forestry Commissioning Operation Using Ant Colony Optimisation.\nYear: 2014\n\nAbstract: This paper formulates a vehicle routing problem where constraints have been produced from a real world forestry commissioning dataset. In the problem, vehicles are required to fully load wood from forests and then deliver the wood to sawmills. The constraints include time windows and loading bay constraints at forests and sawmills. The loading bay constraints are examples of inter-route constraints that have not been studied in the literature as much as intra-route constraints. Inter-route constraints are constraints that cause dependencies between vehicles such that more than one vehicle is required to perform a task. Some locations have a lot of consignments at similar times, causing vehicles to queue for loading bays. The aim is to produce an optimal routing of consignments for vehicles such that the total time is minimised and there is as little queuing at forests and sawmills as possible. In this paper, the problem has been formulated into a vehicle routing problem with time windows and extra inter-route constraints. An ant colony optimisation heuristic is applied to the datasets and yields feasible solutions that appropriately use the loading bays. A number of methods of handling the inter-route constraints are also tested. It is shown that incorporating the delay times at loading bays into the ant's visibility produces solutions with the best objective values.","Title: New Solution for a Benchmark Nurse Scheduling Problem Using Integer Programming\nYear: 2014\n\nAbstract: In this paper, we formulate nurse scheduling problem in modern hospital environment as an integer programming (IP) problem. We simplify the nurse scheduling problem by transforming it through Information Granulation which enables the original problem to be expressed and solved more easily. The solution of the simplified problem is followed by a refinement of this solution to ensure that all constraints of the original problem are taken into account. We have used the GNU Octave, open source mathematical modelling and simulation software for Windows to solve the simplified problem expressed as Integer Programming problem. We used the branch and bound and dual simplex version of the integer programming solver. Very promising results from the real life benchmark problem sets are reported and are compared to the results reported in the literature. Results show that the proposed algorithm facilitates computation of feasible schedules in a short time. We suggest that the proposed methodology can be applied to other resource allocation problems with a large number of constraints.","Title: Automatic Design of a Hyper-Heuristic Framework With Gene Expression Programming for Combinatorial Optimization Problems\nYear: 2015\n\nAbstract: Hyper-heuristic approaches aim to automate heuristic design in order to solve multiple problems instead of designing tailor-made methodologies for individual problems. Hyper-heuristics accomplish this through a high-level heuristic (heuristic selection mechanism and an acceptance criterion). This automates heuristic selection, deciding whether to accept or reject the returned solution. The fact that different problems, or even instances, have different landscape structures and complexity, the design of efficient high-level heuristics can have a dramatic impact on hyper-heuristic performance. In this paper, instead of using human knowledge to design the high-level heuristic, we propose a gene expression programming algorithm to automatically generate, during the instance-solving process, the high-level heuristic of the hyper-heuristic framework. The generated heuristic takes information (such as the quality of the generated solution and the improvement made) from the current problem state as input and decides which low-level heuristic should be selected and the acceptance or rejection of the resultant solution. The benefit of this framework is the ability to generate, for each instance, different high-level heuristics during the problem-solving process. Furthermore, in order to maintain solution diversity, we utilize a memory mechanism that contains a population of both high-quality and diverse solutions that is updated during the problem-solving process. The generality of the proposed hyper-heuristic is validated against six well-known combinatorial optimization problems, with very different landscapes, provided by the HyFlex software. Empirical results, comparing the proposed hyper-heuristic with state-of-the-art hyper-heuristics, conclude that the proposed hyper-heuristic generalizes well across all domains and achieves competitive, if not superior, results for several instances on all domains.","Title: Grammatical Evolution Hyper-Heuristic for Combinatorial Optimization Problems\nYear: 2013\n\nAbstract: Designing generic problem solvers that perform well across a diverse set of problems is a challenging task. In this work, we propose a hyper-heuristic framework to automatically generate an effective and generic solution method by utilizing grammatical evolution. In the proposed framework, grammatical evolution is used as an online solver builder, which takes several heuristic components (e.g., different acceptance criteria and different neighborhood structures) as inputs and evolves templates of perturbation heuristics. The evolved templates are improvement heuristics, which represent a complete search method to solve the problem at hand. To test the generality and the performance of the proposed method, we consider two well-known combinatorial optimization problems: exam timetabling (Carter and ITC 2007 instances) and the capacitated vehicle routing problem (Christofides and Golden instances). We demonstrate that the proposed method is competitive, if not superior, when compared to state-of-the-art hyper-heuristics, as well as bespoke methods for these different problem domains. In order to further improve the performance of the proposed framework we utilize an adaptive memory mechanism, which contains a collection of both high quality and diverse solutions and is updated during the problem solving process. Experimental results show that the grammatical evolution hyper-heuristic, with an adaptive memory, performs better than the grammatical evolution hyper-heuristic without a memory. The improved framework also outperforms some bespoke methodologies, which have reported best known results for some instances in both problem domains.","Title: Sparse Double-Geometric Nonlocal Mean image recovery via steerable kernel\nYear: 2015\n\nAbstract: It has been proved that the geometric information in images produce most stimulus of human eyes, which is important for the image recovery. However, the local geometric structure in images are too diverse to be accurately captured. Recent decade has witnessed a flourish of biological inspired algorithms in the image recovery. In this paper, inspired the adaptive and sparse characteristic of visual perception of humans, we advance an adaptive steerable kernel based Sparse Double-Geometric Nonlocal Mean (SDGNLM) denoising algorithm by exploring the local geometric information in both the \\\"neighbor location\\\" and \\\"similarity measure\\\". In our method, a steerable kernel is employed to reveal the local geometric information of pixels, and sparse assumption of neighbors is cast on pixels to achieve more accurate image recovery. Moreover, a weighted sparse optimization algorithm is proposed to find and weight neighbors having the similar characteristics with each pixel. Some experiments are taken on some benchmark natural images, and the experimental results demonstrate its superiorities to NLM algorithm and its variants, in terms of both visual results and numerical guidelines.","Title: An Improved MOEA/D for QoS Oriented Multimedia Multicasting with Network Coding.\nYear: 2015\n\nAbstract: Recent years witness a significant growth in multimedia applications. Among them, a stream of applications is real-time and requires one-to-many fast data transmission with stringent quality-of-service (QoS) requirements, where multicast is an important supporting technology. In particular, with more and more mobile end users requesting real-time broadband multimedia applications, it is of vital importance to provide them with satisfied quality of experience. As network coding can offer higher bandwidth to users and accommodate more flows for networks than traditional routing, this paper studies the multicast routing problem with network coding and formulates it as a multi-objective optimization problem. As delay and packet loss ratio (PLR) are two important performance indicators for QoS, we consider them as the two objectives for minimization. To address the problem above, we present a multi-objective evolutionary algorithm based on decomposition (MOEA/D), where an all population updating rule is devised to address the problem of lacking feasible solutions in the search space. Experimental results demonstrate the effectiveness of the proposed algorithm and it outperforms a number of state-of-the-art algorithms.","Title: Good Laboratory Practice for optimization research.\nYear: 2016\n\nAbstract: Good Laboratory Practice has been a part of non-clinical research for over 40 years. Optimization Research, despite having many papers discussing standards being published over the same period of time, has yet to embrace standards that underpin its research. In this paper we argue the need to adopt standards in optimization research. Building on previous papers, many of which have suggested that the optimization research community should adopt certain standards, we suggest a concrete set of recommendations that the community should adopt. We also discuss how the proposals in this paper could be progressed.Keywords: optimization, operations research, reproducibility","Title: A Hybrid Genetic Algorithm For A Two-Stage Stochastic Portfolio Optimization With Uncertain Asset Prices\nYear: 2015\n\nAbstract: Portfolio optimization is one of the most important problems in the finance field. The traditional mean-variance model has its drawbacks since it fails to take the market uncertainty into account. In this work, we investigate a two-stage stochastic portfolio optimization model with a comprehensive set of real world trading constraints in order to capture the market uncertainties in terms of future asset prices. A hybrid approach, which integrates genetic algorithm (GA) and a linear programming (LP) solver is proposed in order to solve the model, where GA is used to search for the assets selection heuristically and the LP solver solves the corresponding sub-problems of weight allocation optimally. Scenarios are generated to capture uncertain prices of assets for five benchmark market instances. The computational results indicate that the proposed hybrid algorithm can obtain very promising solutions. Possible future research directions are also discussed.","Title: A Modified Ant Colony Optimization Algorithm for Network Coding Resource Minimization.\nYear: 2016\n\nAbstract: This paper presents a modified ant colony optimization (ACO) approach for the network coding resource minimization problem. It is featured with several attractive mechanisms specially devised for solving the concerned problem: 1) a multidimensional pheromone maintenance mechanism is put forward to address the issue of pheromone overlapping; 2) problem-specific heuristic information is employed to ...","Title: Constrained Portfolio Optimisation: The State-of-the-Art Markowitz Models.\nYear: 2016\n\nAbstract: This paper studies the state-of-art constrained portfolio optimisation models, using exact solver to identify the optimal solutions or lower bound for the benchmark instances at the OR-library with extended constraints. The effects of pre-assignment, round-lot, and class constraints based on the quantity and cardinality constrained Markowitz model are firstly investigated to gain insights of increased problem difficulty, followed by the analysis of various constraint settings including those mostly studied in the literature. The study aims to provide useful guidance for future investigations in computational algorithms","Title: A Variable Neighbourhood Search Algorithm with Compound Neighbourhoods for VRPTW.\nYear: 2016\n\nAbstract: The Vehicle Routing Problem with Time Windows (VRPTW) consists of constructing least cost routes from a depot to a set of geographically scattered service points and back to the depot, satisfying service time interval and capacity constraints. A Variable Neighbourhood Search algorithm with Compound Neighbourhoods is proposed to solve VRPTW in this paper. A number of independent neighbourhood operators are composed into compound neighbourhood operators in a new way, to explore wider search area concerning two objectives (to minimize the number of vehicles and the total travel distance) simultaneously. Promising results are obtained on benchmark datasets","Title: Towards an Efficient API for Optimisation Problems Data.\nYear: 2016\n\nAbstract: The literature presents many application programming interfaces (APIs) and frameworks that provide state of the art algorithms and techniques for solving optimisation problems. The same cannot be said about APIs and frameworks focused on the problem data itself because with the peculiarities and details of each variant of a problem, it is virtually impossible to provide general tools that are broad enough to be useful on a large scale. However, there are benefits of employing problem-centred APIs in a R&D environment: improving the understanding of the problem, providing fairness on the results comparison, providing efficient data structures for different solving techniques, etc. Therefore, in this work we propose a novel design methodology for an API focused on an optimisation problem. Our methodology relies on a data parser to handle the problem specification files and on a set of efficient data structures to handle the information on memory, in an intuitive fashion for researchers and efficient for the solving algorithms. Also, we present the concepts of a solution dispenser that can manage solutions objects in memory better than built-in garbage collectors. Finally, we describe the positive results of employing a tailored API to a project involving the development of optimisation solutions for workforce scheduling and routing problems.","Title: Hybridising Local Search With Branch-And-Bound For Constrained Portfolio Selection Problems\nYear: 2016\n\nAbstract: In this paper, we investigate a constrained portfolio selection problem with cardinality constraint, minimum size and position constraints, and non-convex transaction cost. A hybrid method named Local Search Branch-and-Bound (LS-B&B) which integrates local search with B&B is proposed based on the property of the problem, i.e. cardinality constraint. To eliminate the computational burden which is mainly due to the cardinality constraint, the corresponding set of binary variables is identified as core variables. Variable fixing (Bixby, Fenelon et al. 2000) is applied on the core variables, together with a local search, to generate a sequence of simplified sub-problems. The default B&B search then solves these restricted and simplified sub-problems optimally due to their reduced size comparing to the original one. Due to the inherent similar structures in the sub-problems, the solution information is reused to evoke the repairing heuristics and thus accelerate the solving procedure of the sub-problems in B&B. The tight upper bound identified at early stage of the search can discard more sub-problems to speed up the LS-B&B search to the optimal solution to the original problem. Our study is performed on a set of portfolio selection problems with non-convex transaction costs and a number of trading constraints based on the extended mean-variance model. Computational experiments demonstrate the effectiveness of the algorithm by using less computational time.","Title: A quantum inspired evolutionary algorithm for dynamic multicast routing with network coding\nYear: 2016\n\nAbstract: This paper studies and models the multicast routing problem with network coding in dynamic network environment, where computational and bandwidth resources are to be jointly optimized. A quantum inspired evolutionary algorithm (QEA) is developed to address the problem above, where a restart scheme is devised for well adapting QEA for tracing the ever-changing optima in dynamic environment. Experimental results show that the proposed QEA outperforms a number of existing evolutionary algorithms in terms of the best solution obtained.","Title: Mean-VaR portfolio optimization: A nonparametric approach.\nYear: 2017\n\nAbstract: •Present a new MOEA for complex portfolio optimization.•Six real-world trading constraints are considered.•Computational experiments are performed by using real market data.•Results show the effectiveness of the learning mechanism.•Proposed method yield improved performance relative to existing methods.","Title: An improved MOEA/D algorithm for multi-objective multicast routing with network coding.\nYear: 2017\n\nAbstract: •Formulate a network-coding-based multicast routing problem with three objectives.•Propose a hybrid multi-objective evolutionary algorithm incorporating PBIL into MOEA/D.•Develop a probability-based initialization scheme, a population updating rule, and a reproduction operator.","Title: A hybrid EDA for load balancing in multicast with network coding.\nYear: 2017\n\nAbstract: •Model a load balancing optimization problem in the context of network coding based multicast in communication networks.•Propose a hybridized PBIL with two novel performance-improving schemes, namely the bi-probability-vector co-evolution scheme and the local search heuristic.•Experimental results demonstrate that the proposed algorithm outperforms a number of state-of-the-art evolutionary algorithms with respect to the solution quality.","Title: Automated Design of Machine Learning and Search Algorithms [Guest Editorial].\nYear: 2018\n\nAbstract: The three articles in this special section focus on the development of automated design of machine learning and search algorithms. There is a demand, especially from industry and business, to automate the design of machine learning and search algorithms, thereby removing the heavy reliance on human experts. Machine learning and search techniques play an important role in solving real-world complex...","Title: Hybrid multi-objective evolutionary algorithms based on decomposition for wireless sensor network coverage optimization.\nYear: 2018\n\nAbstract: •This paper models the coverage control optimization problem in WSN as a multi-objective optimization problem considering multiple objectives.•A hybrid reproduction operator based on Genetic Algorithm (GA) and Differential Evolution (DE) has been proposed to diversify the search.•An discrete binary particle swarm optimization method has been designed as the enhancement strategy to obtain a better Pareto solution set.•Large amount of experiments have been carried out to demonstrate the effectiveness of our proposed algorithms.","Title: Course Recommendation Model in Academic Social Networks Based on Association Rules and Multi -similarity\nYear: 2018\n\nAbstract: Compared with traditional course websites, the open online course platforms have a larger number of courses, and course recommendation is becoming increasingly important. In this paper, we shall propose a course recommendation model based on academic social networks, a hybrid method combing with association rules algorithm and an improved multi-similarity algorithm of multi-source information, which can recommend courses according to potential relationships between courses and users implicit interests. The proposed model is applied to SCHOLAT. Judging from our experimental results, the new model is capable of reducing cold-start problem and providing better accuracy.","Title: A hyper-heuristic with two guidance indicators for bi-objective mixed-shift vehicle routing problem with time windows.\nYear: 2018\n\nAbstract: In this paper, a Mixed-Shift Vehicle Routing Problem is proposed based on a real-life container transportation problem. In a long planning horizon of multiple shifts, transport tasks are completed satisfying the time constraints. Due to the different travel distances and time of tasks, there are two types of shifts (long shift and short shift) in this problem. The unit driver cost for long shifts is higher than that of short shifts. A mathematical model of this Mixed-Shift Vehicle Routing Problem with Time Windows (MS-VRPTW) is established in this paper, with two objectives of minimizing the total driver payment and the total travel distance. Due to the large scale and nonlinear constraints, the exact search showed is not suitable to MS-VRPTW. An initial solution construction heuristic (EBIH) and a selective perturbation Hyper-Heuristic (GIHH) are thus developed. In GIHH, five heuristics with different extents of perturbation at the low level are adaptively selected by a high level selection scheme with the Hill Climbing acceptance criterion. Two guidance indicators are devised at the high level to adaptively adjust the selection of the low level heuristics for this bi-objective problem. The two indicators estimate the objective value improvement and the improvement direction over the Pareto Front, respectively. To evaluate the generality of the proposed algorithms, a set of benchmark instances with various features is extracted from real-life historical datasets. The experiment results show that GIHH significantly improves the quality of the final Pareto Solution Set, outperforming the state-of-the-art algorithms for similar problems. Its application on VRPTW also obtains promising results.","Title: Computing semantic similarity based on novel models of semantic representation using Wikipedia.\nYear: 2018\n\nAbstract: •Two semantic models for the representation of concepts are proposed.•The presented semantic models focus on Wikipedia Category Graph and hyperlinks.•Several methods to semantic similarity computation for concepts are provided.","Title: An Investigation on Compound Neighborhoods for VRPTW.\nYear: 2016\n\nAbstract: The Vehicle Routing Problem with Time Windows (VRPTW) consists of constructing least cost routes from a depot to a set of geographically scattered service points and back to the depot, satisfying service time intervals and capacity constraints. A Variable Neighbourhood Search algorithm which can simultaneously optimize both objectives of VRPTW (to minimize the number of vehicles and the total travel distance) is proposed in this paper. The three compound neighbourhood operators are developed with regards to problem characteristics of VRPTW. Compound neighbourhoods combine a number of independent neighbourhood operators to explore a larger scale of neighbourhood search space. Performance of these operators has been investigated and is evaluated on benchmark problems.","Title: Fusion of Panchromatic and Multispectral Images via Coupled Sparse Non-Negative Matrix Factorization.\nYear: 2016\n\nAbstract: In this paper, we construct a new coupled sparse non-negative matrix factorization (CSNMF) model for the fusion of panchromatic (PAN) and multispectral (MS) images. Two CSNMFs are developed for a joint sparse representation of MS and PAN images. Moreover, a sequential iterative algorithm is proposed to simultaneously find the solution to CSNMF. Because learned dictionaries can reveal the latent st...","Title: Hyper-heuristics: a survey of the state of the art.\nYear: 2013\n\nAbstract: Hyper-heuristics comprise a set of approaches that are motivated (at least in part) by the goal of automating the design of heuristic methods to solve hard computational search problems. An underlying strategic research challenge is to develop more generally applicable search methodologies. The term hyperheuristic is relatively new; it was first used in 2000 to describe heuristics to choose heuristics in the context of combinatorial optimisation. However, the idea of automating the design of heuristics is not new; it can be traced back to the 1960s. The definition of hyper-heuristics has been recently extended to refer to a search method or learning mechanism for selecting or generating heuristics to solve computational search problems. Two main hyper-heuristic categories can be considered: heuristic selection and heuristic generation. The distinguishing feature of hyper-heuristics is that they operate on a search space of heuristics (or heuristic components) rather than directly on the search space of solutions to the underlying problem that is being addressed. This paper presents a critical discussion of the scientific literature on hyper-heuristics including their origin and intellectual roots, a detailed account of the main types of approaches, and an overview of some related areas. Current research trends and directions for future research are also discussed.","Title: Multi-objective ant colony optimization algorithm based on decomposition for community detection in complex networks\nYear: 2019\n\nAbstract: Community detection aims to identify topological structures and discover patterns in complex networks, which presents an important problem of great significance. The problem can be modeled as an NP hard combinatorial optimization problem, to which multi-objective optimization has been applied, addressing the common resolution limitation problem in modularity-based optimization. In the literature, ant colony optimization (ACO) algorithm, however, has been only applied to community detection with single objective. This is due to the main difficulties in defining and updating the pheromone matrices, constructing the transition probability model, and tuning the parameters. To address these issues, a multi-objective ACO algorithm based on decomposition (MOACO/D-Net) is proposed in this paper, minimizing negative ratio association and ratio cut simultaneously in community detection. MOACO/D-Net decomposes the community detection multi-objective optimization problem into several subproblems, and each one corresponds to one ant in the ant colony. Furthermore, the ant colony is partitioned into groups, and ants in the same group share a common pheromone matrix with information learned from high-quality solutions. The pheromone matrix of each group is updated based on updated nondominated solutions in this group. New solutions are constructed by the ants in each group using a proposed transition probability model, and each of them is then improved by an improvement operator based on the definition of strong community. After improvement, all the solutions are compared with the solutions in the external archive and the nondominated ones are added to the external archive. Finally each ant updates its current solution based on a better neighbor, which may belong to an adjacent group. The resulting final external archive consists of nondominated solutions, and each one corresponds to a different partition of the network. Systematic experiments on LFR benchmark networks and eight real-world networks demonstrate the effectiveness and robustness of the proposed algorithm. The ranges of proper values for each parameter are also analyzed, addressing the key issue of parameter tuning in ACO algorithms based on a large number of tests conducted.","Title: Semantic similarity measures for formal concept analysis using linked data and WordNet\nYear: 2019\n\nAbstract: Formal Concept Analysis (FCA) is a field of applied mathematics with its roots in order theory, in particular the theory of complete lattices. It is not only a method for data analysis and knowledge representation, but also a formal formulation for concept formation and learning. Over the past 20 years, FCA has been widely studied. In this paper, the current research progresses and the existing problems of similarity measures in FCA are analyzed. To address the drawbacks of the existing methods, we propose a kind of novel semantic similarity measure for FCA by using Linked Data and WordNet. We aim to develop a method that is fully automatic without requiring predefined domain ontologies and can be used independently of the domain in applications requiring semantic similarity measures in FCA. To realize the semantic similarity estimation for FCA, we firstly extend the similarity assessment methods for resources (or entities) in Linked Data into semantic cases by using WordNet. Furthermore, we propose two kinds of semantic similarity measures (i.e., context-free method and context-aware method) for FCA concepts and concept lattices, respectively. Compared with the existing similarity measure methods in FCA, the proposed approach uses concept of possibility theory to determine lower and upper bounds of similarity intervals. Finally, we evaluate the proposed similarity assessment approaches by applying them to real-worlds datasets.","Title: Automated design of search algorithms: Learning on algorithmic components\nYear: 2021\n\nAbstract: This paper proposes AutoGCOP, a new general framework for automated design of local search algorithms. In a recently established General Combinatorial Optimisation Problem (GCOP) model, the problem of algorithm design itself is defined as a combinatorial optimisation problem. AutoGCOP defines a general framework to optimise the composition of elementary algorithmic components as decision variables in GCOP. By modelling various well-known local search meta-heuristics within a general framework, AutoGCOP supports automatic design of new novel algorithms which may be highly different from those manually designed in the literature.","Title: Assessing hyper-heuristic performance\nYear: 2021\n\nAbstract: Limited attention has been paid to assessing the generality performance of hyper-heuristics. The performance of hyper-heuristics has been predominately assessed in terms of optimality which is not ideal as the aim of hyper-heuristics is not to be competitive with state of the art approaches but rather to raise the level of generality, i.e. the ability of a technique to produce good results for different problem instances or problems rather than the best results for some instances and poor results for others. Furthermore from existing literature in this area it is evident that different hyper-heuristics aim to achieve different levels of generality and need to be assessed as such. To cater for this the paper firstly presents a new taxonomy of four different levels of generality that can be attained by a hyper-heuristic based on a survey of the literature. The paper then proposes a performance measure to assess the performance of different types of hyper-heuristics at the four levels of generality in terms of generality rather than optimality. Three case studies from the literature are used to demonstrate the application of the generality performance measure. The paper concludes by examining how the generality measure can be combined with measures of other performance criteria, such as optimality, to assess hyper-heuristic performance on more than one criterion.","Title: An ACO for energy-efficient and traffic-aware virtual machine placement in cloud computing\nYear: 2022\n\nAbstract: This paper formulates a virtual machine placement (VMP) problem, where the total power consumption of physical machines (PMs) and switches and the total network bandwidth resource consumption among VMs are jointly minimized. To address the problem, we present an energy- and traffic-aware ant colony optimization (ETA-ACO) algorithm. Three novel schemes are introduced to enhance the performance of ETA-ACO, including an energy- and bandwidth-aware PM selection scheme, a traffic-based VM ordering scheme, and a direct information exchange scheme. The first scheme consists of two steps when selecting a PM to host a given VM. In the first step, PMs with lower power consumption are preserved. In the second step, the one with the lowest bandwidth resource consumption is chosen to host the VM. In the second scheme, ETA-ACO places VMs in descending order by their traffic demands. The third scheme constructs new solutions by spreading the components of the best solution over a group of constructed solutions. Simulation results demonstrate that the three novel schemes are effective in adapting ETA-ACO for the VMP problem. Besides, ETA-ACO outperforms a number of state-of-the-art heuristics and metaheuristics in terms of solution quality.","Title: Adaptive Fuzzy Learning Superpixel Representation for PolSAR Image Classification\nYear: 2022\n\nAbstract: The increasing applications of polarimetric synthetic aperture radar (PolSAR) image classification demand for effective superpixels' algorithms. Fuzzy superpixels' algorithms reduce the misclassification rate by dividing pixels into superpixels, which are groups of pixels of homogenous appearance and undetermined pixels. However, two key issues remain to be addressed in designing a fuzzy superpixel algorithm for PolSAR image classification. First, the polarimetric scattering information, which is unique in PolSAR images, is not effectively used. Such information can be utilized to generate superpixels more suitable for PolSAR images. Second, the ratio of undetermined pixels is fixed for each image in the existing techniques, ignoring the fact that the difficulty of classifying different objects varies in an image. To address these two issues, we propose a polarimetric scattering information-based adaptive fuzzy superpixel (AFS) algorithm for PolSAR images classification. In AFS, the correlation between pixels' polarimetric scattering information, for the first time, is considered through fuzzy rough set theory to generate superpixels. This correlation is further used to dynamically and adaptively update the ratio of undetermined pixels. AFS is evaluated extensively against different evaluation metrics and compared with the state-of-the-art superpixels' algorithms on three PolSAR images. The experimental results demonstrate the superiority of AFS on PolSAR image classification problems.","Title: Case-based reasoning system for fault diagnosis of aero-engines\nYear: 2022\n\nAbstract: •A highly accurate CBR system with novel similarity measure for fault diagnosis.•Integrating three local similarity measures associated with different attributes.•A tree-based semantic similarity measure linking fault part and fault mode.•The first tentative case base in the field of aero-engine fault diagnosis.","Title: A deep reinforcement learning based hyper-heuristic for combinatorial optimisation with uncertainties\nYear: 2022\n\nAbstract: •A hyper-heuristic framework is proposed for online combinatorial optimisation.•A deep reinforcement learning agent is first used in hyper-heuristic.•The method holds better convergence performance than the existing methods.•Our approach improves the interpretability of traditional DRL.","Title: Identify Patterns in Online Bin Packing Problem: An Adaptive Pattern-Based Algorithm\nYear: 2022\n\nAbstract: Bin packing is a typical optimization problem with many real-world application scenarios. In the online bin packing problem, a sequence of items is revealed one at a time, and each item must be packed into a bin immediately after its arrival. Inspired by duality in optimization, we proposed pattern-based adaptive heuristics for the online bin packing problem. The idea is to predict the distribution of items based on packed items, and to apply this information in packing future arrival items in order to handle uncertainty in online bin packing. A pattern in bin packing is a combination of items that can be packed into a single bin. Patterns selected according to past items are adopted and periodically updated in scheduling future items in the algorithm. Symmetry in patterns and the stability of patterns in the online bin packing problem are discussed. We have implemented the algorithm and compared it with the Best-Fit in a series of experiments with various distribution of items to show its effectiveness.","Title: An Improved Ant Colony Approach for the Competitive Traveling Salesmen Problem\nYear: 2022\n\nAbstract: A competitive traveling salesmen problem is a variant of traveling salesman problem in that multiple agents compete with each other in visiting a number of cities. The agent who is the first one to visit a city will receive a reward. Each agent aims to collect as more rewards as possible with the minimum traveling distance. There is still not effective algorithms for this complicated decision making problem. We investigate an improved ant colony approach for the competitive traveling sales-men problem which adopts a time dominance mechanism and a revised pheromone depositing method to improve the quality of solutions with less computational complexity. Simulation results show that the proposed algorithm outperforms the state of art algorithms."],"string":"[\n \"Title: A shift sequence based approach for nurse scheduling and a new benchmark dataset\\nYear: 2010\\n\\nAbstract: This paper investigates an adaptive constructive method for solving nurse rostering problems. The constraints considered in the problems are categorised into three classes: those that are sequence related, those that are nurse schedule related and those that are roster related. We propose a decomposition approach (to construct solutions) that consists of two stages: (1) to construct high quality sequences for nurses by only considering the sequence constraints, and (2) to iteratively construct schedules for nurses and the overall rosters, based on the sequences built and considering the schedule and roster constraints. In the second stage of the schedule construction, nurses are ordered and selected adaptively according to the quality of the schedules they were assigned to in the last iteration. Greedy local search is carried out during and after the roster construction, in order to improve the (partial) rosters built. We show that the local search heuristic during the roster construction can further improve the constructed solutions for the benchmark problems tested.In addition, we introduce new benchmark nurse rostering datasets which are based upon real world data. The data sets represent a variety of real world constraints. The publication of this problem data to the research community is aimed at closing the gap between theory and practice in nurse scheduling research. One of the main objectives is to encourage more research on these data sets.\",\n \"Title: A constraint programming based column generation approach to nurse rostering problems\\nYear: 2012\\n\\nAbstract: This paper presents our investigations on a hybrid constraint programming based column generation (CP-CG) approach to nurse rostering problems. We present a complete model to formulate all the complex real-world constraints in several benchmark nurse rostering problems. The hybrid CP-CG approach is featured with not only the effective relaxation and optimality reasoning of linear programming but also the powerful expressiveness of constraint programming in modeling the complex logical constraints in nurse rostering problems. In solving the CP pricing subproblem, we propose two strategies to generate promising columns which contribute to the efficiency of the CG procedure. A Depth Bounded Discrepancy Search is employed to obtain diverse columns. A cost threshold is adaptively tightened based on the information collected during the search to generate columns of good quality. Computational experiments on a set of benchmark nurse rostering problems demonstrate a faster convergence by the two strategies and justify the effectiveness and efficiency of the hybrid CP-CG approach.\",\n \"Title: A simulated annealing based genetic local search algorithm for multi-objective multicast routing problems.\\nYear: 2013\\n\\nAbstract: This paper presents a new hybrid evolutionary algorithm to solve multi-objective multicast routing problems in telecommunication networks. The algorithm combines simulated annealing based strategies and a genetic local search, aiming at a more flexible and effective exploration and exploitation in the search space of the complex problem to find more non-dominated solutions in the Pareto Front. Due to the complex structure of the multicast tree, crossover and mutation operators have been specifically devised concerning the features and constraints in the problem. A new adaptive mutation probability based on simulated annealing is proposed in the hybrid algorithm to adaptively adjust the mutation rate according to the fitness of the new solution against the average quality of the current population during the evolution procedure. Two simulated annealing based search direction tuning strategies are applied to improve the efficiency and effectiveness of the hybrid evolutionary algorithm. Simulations have been carried out on some benchmark multi-objective multicast routing instances and a large amount of random networks with five real world objectives including cost, delay, link utilisations, average delay and delay variation in telecommunication networks. Experimental results demonstrate that both the simulated annealing based strategies and the genetic local search within the proposed multi-objective algorithm, compared with other multi-objective evolutionary algorithms, can efficiently identify high quality non-dominated solution set for multi-objective multicast routing problems and outperform other conventional multi-objective evolutionary algorithms in the literature. © 2013 Springer Science+Business Media New York.\",\n \"Title: Adaptive automated construction of hybrid heuristics for exam timetabling and graph colouring problems\\nYear: 2009\\n\\nAbstract: In this paper, we present a random iterative graph based hyper-heuristic to produce a collection of heuristic sequences to construct solutions of different quality. These heuristic sequences can be seen as dynamic hybridisations of different graph colouring heuristics that construct solutions step by step. Based on these sequences, we statistically analyse the way in which graph colouring heuristics are automatically hybridised. This, to our knowledge, represents a new direction in hyper-heuristic research. It is observed that spending the search effort on hybridising Largest Weighted Degree with Saturation Degree at the early stage of solution construction tends to generate high quality solutions. Based on these observations, an iterative hybrid approach is developed to adaptively hybridise these two graph colouring heuristics at different stages of solution construction. The overall aim here is to automate the heuristic design process, which draws upon an emerging research theme on developing computer methods to design and adapt heuristics automatically. Experimental results on benchmark exam timetabling and graph colouring problems demonstrate the effectiveness and generality of this adaptive hybrid approach compared with previous methods on automatically generating and adapting heuristics. Indeed, we also show that the approach is competitive with the state of the art human produced methods.\",\n \"Title: Case-based heuristic selection for timetabling problems\\nYear: 2006\\n\\nAbstract: This paper presents a case-based heuristic selection approach for automated university course and exam timetabling. The method described in this paper is motivated by the goal of developing timetabling systems that are fundamentally more general than the current state of the art. Heuristics that worked well in previous similar situations are memorized in a case base and are retrieved for solving the problem in hand. Knowledge discovery techniques are employed in two distinct scenarios. Firstly, we model the problem and the problem solving situations along with specific heuristics for those problems. Secondly, we refine the case base and discard cases which prove to be non-useful in solving new problems. Experimental results are presented and analyzed. It is shown that case based reasoning can act effectively as an intelligent approach to learn which heuristics work well for particular timetabling situations. We conclude by outlining and discussing potential research issues in this critical area of knowledge discovery for different difficult timetabling problems.\",\n \"Title: Linear combinations of heuristics for examination timetabling.\\nYear: 2012\\n\\nAbstract: Although they are simple techniques from the early days of timetabling research, graph colouring heuristics are still attracting significant research interest in the timetabling research community. These heuristics involve simple ordering strategies to first select and colour those vertices that are most likely to cause trouble if deferred until later. Most of this work used a single heuristic to measure the difficulty of a vertex. Relatively less attention has been paid to select an appropriate colour for the selected vertex. Some recent work has demonstrated the superiority of combining a number of different heuristics for vertex and colour selection. In this paper, we explore this direction and introduce a new strategy of using linear combinations of heuristics for weighted graphs which model the timetabling problems under consideration. The weights of the heuristic combinations define specific roles that each simple heuristic contributes to the process of ordering vertices. We include specific explanations for the design of our strategy and present the experimental results on a set of benchmark real world examination timetabling problem instances. New best results for several instances have been obtained using this method when compared with other constructive methods applied to this benchmark dataset.\",\n \"Title: Solving multi-objective multicast routing problems by evolutionary multi-objective simulated annealing algorithms with variable neighbourhoods\\nYear: 2011\\n\\nAbstract: This paper presents the investigation of an evolutionary multi-objective simulated annealing (EMOSA) algorithm with variable neighbourhoods to solve the multi-objective multicast routing problems in telecommunications. The hybrid algorithm aims to carry out a more flexible and adaptive exploration in the complex search space by using features of the variable neighbourhood search to find more non-dominated solutions in the Pareto front. Different neighbourhood strictures have been designed with regard to the set of objectives, aiming to drive the search towards optimising all objectives simultaneously. A large number of simulations have been carried out on benchmark instances and random networks with real world features including cost, delay and link utilisations. Experimental results demonstrate that the proposed EMOSA algorithm with variable neighbourhoods is able to find high-quality non-dominated solutions for the problems tested. In particular, the neighbourhood structures that are specifically designed for each objective significantly improved the performance of the proposed algorithm compared with variants of the algorithm with a single neighbourhood. Journal of the Operational Research Society (2011) 62, 313-325. doi:10.1057/jors.2010.138 Published online 22 September 2010\",\n \"Title: Analyzing the landscape of a graph based hyper-heuristic for timetabling problems\\nYear: 2009\\n\\nAbstract: Hyper-heuristics can be thought of as \\\"heuristics to choose heuristics\\\". They are concerned with adaptively finding solution methods, rather than directly producing a solution for the particular problem at hand. Hence, an important feature of hyper-heuristics is that they operate on a search space of heuristics rather than directly on a search space of problem solutions. A motivating aim is to build systems which are fundamentally more generic than is possible today. Understanding the structure of these heuristic search spaces is therefore, a research direction worth exploring. In this paper, we use the notion of fitness landscapes in the context of constructive hyper-heuristics. We conduct a landscape analysis on a heuristic search space conformed by sequences of graph coloring heuristics for timetabling. Our study reveals that these landscapes have a high level of neutrality and positional bias. Furthermore, although rugged, they have the encouraging feature of a globally convex or big valley structure, which indicates that an optimal solution would not be isolated but surrounded by many local minima. We suggest that using search methodologies that explicitly exploit these features may enhance the performance of constructive hyper-heuristics.\",\n \"Title: A new model for automated examination timetabling.\\nYear: 2012\\n\\nAbstract: Automated examination timetabling has been addressed by a wide variety of methodologies and techniques over the last ten years or so. Many of the methods in this broad range of approaches have been evaluated on a collection of benchmark instances provided at the University of Toronto in 1996. Whilst the existence of these datasets has provided an invaluable resource for research into examination timetabling, the instances have significant limitations in terms of their relevance to real-world examination timetabling in modern universities. This paper presents a detailed model which draws upon experiences of implementing examination timetabling systems in universities in Europe, Australasia and America.This model represents the problem that was presented in the 2nd International Timetabling Competition (ITC2007). In presenting this detailed new model, this paper describes the examination timetabling track introduced as part of the competition. In addition to the model, the datasets used in the competition are also based on current real-world instances introduced by EventMAP Limited. It is hoped that the interest generated as part of the competition will lead to the development, investigation and application of a host of novel and exciting techniques to address this important real-world search domain. Moreover, the motivating goal of this paper is to close the currently existing gap between theory and practice in examination timetabling by presenting the research community with a rigorous model which represents the complexity of the real-world situation. In this paper we describe the model and its motivations, followed by a full formal definition.\",\n \"Title: Granular Modelling Of Exam To Slot Allocation\\nYear: 2009\\n\\nAbstract: In this paper, we are introducing a new method of granular exam-to-slot allocation based on the preprocessing of the basic student-exam information into a more abstract (granulated) entity of conflict chains. Since the conflict chains are designed to capture the mutual dependencies between exams, they enable us to reason about the exam-to-slot allocation for all exams in a chain rather than just one exam at-a-time. The initial exam-to-slot allocation, generated through the processing of conflict chains, is then refined by considering the spread of the exams in the examination session so as to minimize the appropriately defined cost function. The granular pre-processing of problem data has been shown to enhance the efficiency of the exam scheduling task and has led to the identification of very competitive exam schedules.\",\n \"Title: A hybrid algorithm for constrained portfolio selection problems\\nYear: 2013\\n\\nAbstract: Since Markowitz's seminal work on the mean-variance model in modern portfolio theory, many studies have been conducted on computational techniques and recently meta-heuristics for portfolio selection problems. In this work, we propose and investigate a new hybrid algorithm integrating the population based incremental learning and differential evolution algorithms for the portfolio selection problem. We consider the extended mean-variance model with practical trading constraints including the cardinality, floor and ceiling constraints. The proposed hybrid algorithm adopts a partially guided mutation and an elitist strategy to promote the quality of solution. The performance of the proposed hybrid algorithm has been evaluated on the extended benchmark datasets in the OR Library. The computational results demonstrate that the proposed hybrid algorithm is not only effective but also efficient in solving the mean-variance model with real world constraints.\",\n \"Title: An Adaptive Tie Breaking and Hybridisation Hyper-Heuristic for Exam Timetabling Problems.\\nYear: 2011\\n\\nAbstract: Graph colouring heuristics have long been applied successfully to the exam timetabling problem. Despite the success of a few heuristic ordering criteria developed in the literature, the approaches lack the ability to handle the situations where ties occur. In this paper, we investigate the effectiveness of applying tie breakers to orderings used in graph colouring heuristics. We propose an approach to construct solutions for our problem after defining which heuristics to combine and the amount of each heuristic to be used in the orderings. Heuristic sequences are then adapted to help guide the search to find better quality solutions. We have tested the approach on the Toronto benchmark problems and are able to obtain results which are within the range of the best reported in the literature. In addition, to test the generality of our approach we introduced an exam timetabling instance generator and a new benchmark data set which has a similar format to the Toronto benchmark. The instances generated vary in size and conflict density. The publication of this problem data to the research community is aimed to provide researchers with a data set which covers a full range of conflict densities. Furthermore, it is possible using the instance generator to create random data sets with different characteristics to test the performance of approaches which rely on problem characteristics. We present the first results for the benchmark and the results obtained show that the approach is adaptive to all the problem instances that we address. We also encourage the use of the data set and generator to produce tailored instances and to investigate various methods on them.\",\n \"Title: A Time Predefined Variable Depth Search for Nurse Rostering\\nYear: 2013\\n\\nAbstract: This paper presents a variable depth search for the nurse rostering problem. The algorithm works by chaining together single neighbourhood swaps into more effective compound moves. It achieves this by using heuristics to decide whether to continue extending a chain and which candidates to examine as the next potential link in the chain. Because end users vary in how long they are willing to wait for solutions, a particular goal of this research was to create an algorithm that accepts a user specified computational time limit and uses it effectively. When compared against previously published approaches the results show that the algorithm is very competitive.\",\n \"Title: An iterative local search approach based on fitness landscapes analysis for the delay-constrained multicast routing problem\\nYear: 2012\\n\\nAbstract: This paper presents the first fitness landscape analysis on the delay-constrained least-cost multicast routing problem (DCLC-MRP). Although the problem has attracted an increasing research attention over the past decade in telecommunications and operational research, little research has been conducted to analyze the features of its underlying landscape. Two of the most commonly used landscape analysis techniques, the fitness distance correlation analysis and the autocorrelation analysis, have been applied to analyze the global and local landscape features of DCLC-MRPs. A large amount of simulation experiments on a set of problem instances generated based on the benchmark Steiner tree problems in the OR-library reveals that the landscape of the DCLC-MRP is highly instance dependent with different landscape features. Different delay bounds also affect the distribution of solutions in the search space. The autocorrelation analysis on the benchmark instances of different sizes and delay bounds shows the impact of different local search heuristics and neighborhood structures on the fitness distance landscapes of the DCLC-MRP. The delay bound constraint in the DCLC-MRP has shown a great influence on the underlying landscape characteristic of the problem. Based on the fitness landscape analysis, an iterative local search (ILS) approach is proposed in this paper for the first time to tackle the DCLC-MRP. Computational results demonstrate the effectiveness of the proposed ILS algorithm for the problem in comparison with other algorithms in the literature.\",\n \"Title: A honey-bee mating optimization algorithm for educational timetabling problems.\\nYear: 2012\\n\\nAbstract: In this work, we propose a variant of the honey-bee mating optimization algorithm for solving educational timetabling problems. The honey-bee algorithm is a nature inspired algorithm which simulates the process of real honey-bees mating. The performance of the proposed algorithm is tested over two benchmark problems: exam (Carter's un-capacitated datasets) and course (Socha datasets) timetabling problems. We chose these two datasets as they have been widely studied in the literature and we would also like to evaluate our algorithm across two different, yet related, domains. Results demonstrate that the performance of the honey-bee mating optimization algorithm is comparable with the results of other approaches in the scientific literature. Indeed, the proposed approach obtains best results compared with other approaches on some instances, indicating that the honey-bee mating optimization algorithm is a promising approach in solving educational timetabling problems. (C) 2011 Elsevier B.V. All rights reserved.\",\n \"Title: Hierarchical Method For Nurse Rostering Based On Granular Pre-Processing Of Constraints\\nYear: 2009\\n\\nAbstract: Nurse Rostering problems represent a subclass of scheduling problems that are hard to solve. Their complexity is due to the large solution spaces and the many objectives and constraints that need to be fulfilled. In this study, we propose a hierarchical method of granulation of problem domain through preprocessing of constraints. A set of zero-cost patterns in the granulated search space provides a basis for the generation of work schedules. Feasible schedules calculated for week 1 are used to define zero-cost shift patterns that can be deployed in week 2. These in turn are used for the generation of feasible schedules for week 2. The process can be applied over the extended time frame. We show that the granulation of the problem description in terms of constraints and scheduling time frames leads to a more manageable computing task.\",\n \"Title: A Variable Neighborhood Descent Search Algorithm for Delay-Constrained Least-Cost Multicast Routing\\nYear: 2009\\n\\nAbstract: The rapid evolution of real-time multimedia applications requires Quality of Service (QoS) based multicast routing in underlying computer networks. The constrained Steiner Tree, as the underpinning mathematical structure, is a well-known NP-complete problem. In this paper we investigate a variable neighborhood descent (VND) search, a variant of variable neighborhood search, for the delay-constrained least-cost (DCLC) multicast routing problem. The neighborhood structures designed in the VND approaches are based on the idea of path replacement in trees. They are simple, yet effective operators, enabling a flexible search over the solution space of this complex problem with multiple constraints. A large number of simulations demonstrate that our algorithm is highly efficient in solving the DCLC multicast routing problem in terms of the tree cost and execution time. To our knowledge, this is the first study of VND algorithm on the DCLC multicast routing problem. It outperforms other existing algorithms over a range of problem instances.\",\n \"Title: A Constraint-Directed Local Search Approach To Nurse Rostering Problems\\nYear: 2009\\n\\nAbstract: In this paper, we investigate the hybridization of constraint programming and local search techniques within a large neighbourhood search scheme for solving highly constrained nurse rostering problems. As identified by the research, a crucial part of the large neighbourhood search is the selection of the fragment (neighbourhood, i. e. the set of variables), to be relaxed and re- optimized iteratively. The success of the large neighbourhood search depends on the adequacy of this identified neighbourhood with regard to the problematic part of the solution assignment and the choice of the neighbourhood size. We investigate three strategies to choose the fragment of different sizes within the large neighbourhood search scheme. The first two strategies are tailored concerning the problem properties. The third strategy is more general, using the information of the cost from the soft constraint violations and their propagation as the indicator to choose the variables added into the fragment. The three strategies are analyzed and compared upon a benchmark nurse rostering problem. Promising results demonstrate the possibility of future work in the hybrid approach.\",\n \"Title: A hybrid model of integer programming and variable neighbourhood search for highly-constrained nurse rostering problems\\nYear: 2010\\n\\nAbstract: This paper presents a hybrid multi-objective model that combines integer programming (IP) and variable neighbourhood search (VNS) to deal with highly-constrained nurse rostering problems in modern hospital environments. An IP is first used to solve the subproblem which includes the full set of hard constraints and a subset of soft constrains. A basic VNS then follows as a postprocessing procedure to further improve the IP’s resulting solutions. The satisfaction of the excluded constraints from the preceding IP model is the major focus of the VNS. Very promising results are reported compared with a commercial genetic algorithm and a hybrid VNS approach on real instances arising in a Dutch hospital. The comparison results demonstrate that our hybrid approach combines the advantages of both the IP and the VNS to beat other approaches in solving this type of problems. We also believe that the proposed methodology can be applied to other resource allocation problems with a large number of constraints.\",\n \"Title: Evolutionary Ruin And Stochastic Recreate: A Case Study On The Exam Timetabling Problem\\nYear: 2012\\n\\nAbstract: This paper presents a new class of intelligent systems, called Evolutionary Ruin and Stochastic Recreate, that can learn and adapt to the changing enviroment. It improves the original Ruin and Recreate principle's performance by incorporating an Evolutionary Ruin step which implements evolution within a single solution. In the proposed approach, a cycle of Solution Decomposition, Evolutionary Ruin and Stochastic Recreate continues until stopping conditions are reached. The Solution Decomposition step first uses some domain knowledge to break a solution down into its components and assign a score to each. The Evolutionary Ruin step then applies two operators (namely Selection and Mutation) to destroy a certain fraction of the entire solution. After the above steps, an input solution becomes partial and thus the resulting partial solution needs to be repaired. The repair is carried out by using the Stochastic Recreate step to reintroduce the removed items in a specific way (somewhat stochastic in order to have a better chance to jump out of the local optima), and then ask the underlying improvement heuristic whether this move will be accepted. These three steps are executed in sequence until a specific stopping condition is reached. Therefore, optimisation is achieved by solution disruption, iterative improvement and a stochastic constructive repair process performed within. Encouraging experimental results on exam timetabling problems are reported.\",\n \"Title: A Population Based Incremental Learning for Network Coding Resources Minimization.\\nYear: 2011\\n\\nAbstract: In network coding based multicast, coding operations need to be minimized as they consume computational resources and increase data processing complexity at corresponding nodes in the network. To address the problem, we develop a population based incremental learning algorithm which shows to outperform existing algorithms in terms of both the solution obtained and computational time consumed on networks with various features.\",\n \"Title: A hybrid scatter search meta-heuristic for delay-constrained multicast routing problems\\nYear: 2012\\n\\nAbstract: This paper investigates the first hybrid scatter search and path relinking meta-heuristic for the Delay-Constrained Least-Cost (DCLC) multicast routing problem. The underpinning mathematic model of the DCLC multicast routing problem is the constrained Steiner tree problem in graphs, a well known NP-complete problem. After combining a path relinking method as the solution combination method in scatter search, we further explore two improvement strategies: tabu search and variable neighborhood search, to intensify the search in the hybrid scatter search algorithm. A large number of simulations on some benchmark instances from the OR-library and a group of random graphs of different characteristics demonstrate that the improvement strategy greatly affects the performance of the proposed scatter search algorithm. The hybrid scatter search algorithm intensified by a variable neighborhood descent search is highly efficient in solving the DCLC multicast routing problem in comparison with other algorithms and heuristics in the literature.\",\n \"Title: Personnel scheduling: Models and complexity\\nYear: 2011\\n\\nAbstract: Due to its complexity, its challenging features, and its practical relevance, personnel scheduling has been heavily investigated in the last few decades. However, there is a relatively low level of study on models and complexity in these important problems. In this paper, we present mathematical models which cover specific aspects in the personnel scheduling literature. Furthermore, we address complexity issues by identifying polynomial solvable and NP-hard special cases.\",\n \"Title: A Study Of Cost Effective Scheduling Of Nurses Based On The Domain Transformation Method\\nYear: 2013\\n\\nAbstract: This paper discusses and analyses the tradeoff between the flexibility afforded with greater number of staff and the implied cost of employing extra staff in the context of the nurse-scheduling problem. If the number of staff is constant, our study allows quantification of the degree of pressure put on the staff resulting from the schedules that do not satisfy their preferences for shift allocation. We present a practical approach, based on our domain transformation methodology that achieves good quality schedules without high computational requirements.\",\n \"Title: A pattern recognition based intelligent search method and two assignment problem case studies\\nYear: 2012\\n\\nAbstract: Numerous papers based on various search methods across a wide variety of applications have appeared in the literature over\\n recent years. Most of these methods apply the following same approach to address the problems at hand: at each iteration of\\n the search, they first apply their search methods to generate new solutions, then they calculate the objective values (or\\n costs) by taking some constraints into account, and finally they use some strategies to determine the acceptance or rejection\\n of these solutions based upon the calculated objective values. However, the premise of this paper is that calculating the\\n exact objective value of every resulting solution is not a must, particularly for highly constrained problems where such a\\n calculation is costly and the feasible regions are small and disconnected. Furthermore, we believe that for newly-generated\\n solutions, evaluating the quality purely by their objective values is sometimes not the most efficient approach. In many combinatorial\\n problems, there are poor-cost solutions where possibly just one component is misplaced and all others work well. Although\\n these poor-cost solutions can be the intermediate states towards the search of a high quality solution, any cost-oriented\\n criteria for solution acceptance would deem them as inferior and consequently probably suggest a rejection. To address the\\n above issues, we propose a pattern recognition-based framework with the target of designing more intelligent and more flexible\\n search systems. The role of pattern recognition is to classify the quality of resulting solutions, based on the solution structure\\n rather than the solution cost. Hence, the general contributions of this work are in the line of “insights” and recommendations.\\n Two real-world cases of the assignment problem, i.e. the hospital personnel scheduling and educational timetabling, are used\\n as the case studies. For each case, we apply neural networks as the tool for pattern recognition. In addition, we present\\n our theoretical and experimental results in terms of runtime speedup.\",\n \"Title: A graph coloring constructive hyper-heuristic for examination timetabling problems\\nYear: 2012\\n\\nAbstract: In this work we investigate a new graph coloring constructive hyper-heuristic for solving examination timetabling problems. We utilize the hierarchical hybridizations of four low level graph coloring heuristics, these being largest degree, saturation degree, largest colored degree and largest enrollment. These are hybridized to produce four ordered lists. For each list, the difficulty index of scheduling the first exam is calculated by considering its order in all lists to obtain a combined evaluation of its difficulty. The most difficult exam to be scheduled is scheduled first (i.e. the one with the minimum difficulty index). To improve the effectiveness of timeslot selection, a roulette wheel selection mechanism is included in the algorithm to probabilistically select an appropriate timeslot for the chosen exam. We test our proposed approach on the most widely used un-capacitated Carter benchmarks and also on the recently introduced examination timetable dataset from the 2007 International Timetabling Competition. Compared against other methodologies, our results demonstrate that the graph coloring constructive hyper-heuristic produces good results and outperforms other approaches on some of the benchmark instances.\",\n \"Title: Particle swarm optimization for the Steiner tree in graph and delay-constrained multicast routing problems\\nYear: 2013\\n\\nAbstract: This paper presents the first investigation on applying a particle swarm optimization (PSO) algorithm to both the Steiner tree problem and the delay constrained multicast routing problem. Steiner tree problems, being the underlining models of many applications, have received significant research attention within the meta-heuristics community. The literature on the application of meta-heuristics to multicast routing problems is less extensive but includes several promising approaches. Many interesting research issues still remain to be investigated, for example, the inclusion of different constraints, such as delay bounds, when finding multicast trees with minimum cost. In this paper, we develop a novel PSO algorithm based on the jumping PSO (JPSO) algorithm recently developed by Moreno-Perez et al. (Proc. of the 7th Metaheuristics International Conference, 2007), and also propose two novel local search heuristics within our JPSO framework. A path replacement operator has been used in particle moves to improve the positions of the particle with regard to the structure of the tree. We test the performance of our JPSO algorithm, and the effect of the integrated local search heuristics by an extensive set of experiments on multicast routing benchmark problems and Steiner tree problems from the OR library. The experimental results show the superior performance of the proposed JPSO algorithm over a number of other state-of-the-art approaches.\",\n \"Title: A scatter search methodology for the nurse rostering problem\\nYear: 2010\\n\\nAbstract: The benefits of automating the nurse scheduling process in hospitals include reducing the planning workload and associated costs and being able to create higher quality and more flexible schedules. This has become more important recently in order to retain nurses and to attract more people into the profession. Better quality rosters also reduce fatigue and stress due to overwork and poor scheduling and help to maximise the use of leisure time by satisfying more requests. A more contented workforce will lead to higher productivity, increased quality of patient service and a better level of healthcare. This paper presents a scatter search approach for the problem of automatically creating nurse rosters. Scatter search is an evolutionary algorithm, which has been successfully applied across a number of problem domains. To adapt and apply scatter search to nurse rostering, it was necessary to develop novel implementations of some of scatter search's subroutines. The algorithm was then tested on publicly available real-world benchmark instances and compared against previously published approaches. The results show the proposed algorithm is a robust and effective method on a wide variety of real-world instances. Journal of the Operational Research Society (2010) 61, 1667-1679. doi: 10.1057/jors.2009.118 Published online 4 November 2009\",\n \"Title: Tabu assisted guided local search approaches for freight service network design\\nYear: 2012\\n\\nAbstract: The service network design problem (SNDP) is a core problem in freight transportation. It involves the determination of the most cost-effective transportation network and the characteristics of the corresponding services, subject to various constraints. The scale of the problem in real-world applications is usually very large, especially when the network contains both the geographical information and the temporal constraints which are necessary for modelling multiple service-classes and dynamic events. The development of time-efficient algorithms for this problem is, therefore, crucial for successful real-world applications. Earlier research indicated that guided local search (GLS) was a promising solution method for this problem. One of the advantages of GLS is that it makes use of both the information collected during the search as well as any special structures which are present in solutions. Building upon earlier research, this paper carries out in-depth investigations into several mechanisms that could potentially speed up the GLS algorithm for the SNDP. Specifically, the mechanisms that we have looked at in this paper include a tabu list (as used by tabu search), short-term memory, and an aspiration criterion. An efficient hybrid algorithm for the SNDP is then proposed, based upon the results of these experiments. The algorithm combines a tabu list within a multi-start GLS approach, with an efficient feasibility-repairing heuristic. Experimental tests on a set of 24 well-known service network design benchmark instances have shown that the proposed algorithm is superior to a previously proposed tabu search method, reducing the computation time by over a third. In addition, we also show that far better results can be obtained when a faster linear program solver is adopted for the sub-problem solution. The contribution of this paper is an efficient algorithm, along with detailed analyses of effective mechanisms which can help to increase the speed of the GLS algorithm for the SNDP.\",\n \"Title: A hybrid heuristic ordering and variable neighbourhood search for the nurse rostering problem\\nYear: 2008\\n\\nAbstract: This paper is concerned with the development of intelligent decision support methodologies for nurse rostering problems in large modern hospital environments. We present an approach which hybridises heuristic ordering with variable neighbourhood search. We show that the search can be extended and the solution quality can be significantly improved by the careful combination and repeated use of heuristic ordering, variable neighbourhood search and back-tracking. The amount of computational time that is allowed plays a significant role and we analyse and discuss this. The algorithms are evaluated against a commercial Genetic Algorithm on commercial data. We demonstrate that this methodology can significantly outperform the commercial algorithm. This paper is one of the few in the scientific nurse rostering literature which deal with commercial data and which compare against a commercially implemented algorithm.\",\n \"Title: Integrating neural networks and logistic regression to underpin hyper-heuristic search\\nYear: 2011\\n\\nAbstract: A hyper-heuristic often represents a heuristic search method that operates over a space of heuristic rules. It can be thought of as a high level search methodology to choose lower level heuristics. Nearly 200 papers on hyper-heuristics have recently appeared in the literature. A common theme in this body of literature is an attempt to solve the problems in hand in the following way: at each decision point, first employ the chosen heuristic(s) to generate a solution, then calculate the objective value of the solution by taking into account all the constraints involved. However, empirical studies from our previous research have revealed that, under many circumstances, there is no need to carry out this costly 2-stage determination and evaluation at all times. This is because many problems in the real world are highly constrained with the characteristic that the regions of feasible solutions are rather scattered and small. Motivated by this observation and with the aim of making the hyper-heuristic search more efficient and more effective, this paper investigates two fundamentally different data mining techniques, namely artificial neural networks and binary logistic regression. By learning from examples, these techniques are able to find global patterns hidden in large data sets and achieve the goal of appropriately classifying the data. With the trained classification rules or estimated parameters, the performance (i.e. the worth of acceptance or rejection) of a resulting solution during the hyper-heuristic search can be predicted without the need to undertake the computationally expensive 2-stage of determination and calculation. We evaluate our approaches on the solutions (i.e. the sequences of heuristic rules) generated by a graph-based hyper-heuristic proposed for exam timetabling problems. Time complexity analysis demonstrates that the neural network and the logistic regression method can speed up the search significantly. We believe that our work sheds light on the development of more advanced knowledge-based decision support systems.\",\n \"Title: A compact genetic algorithm for the network coding based resource minimization problem\\nYear: 2012\\n\\nAbstract: In network coding based data transmission, intermediate nodes in the network are allowed to perform mathematical operations to recombine (code) data packets received from different incoming links. Such coding operations incur additional computational overhead and consume public resources such as buffering and computational resource within the network. Therefore, the amount of coding operations is expected to be minimized so that more public resources are left for other network applications.In this paper, we investigate the newly emerged problem of minimizing the amount of coding operations required in network coding based multicast. To this end, we develop the first elitism-based compact genetic algorithm (cGA) to the problem concerned, with three extensions to improve the algorithm performance. First, we make use of an all-one vector to guide the probability vector (PV) in cGA towards feasible individuals. Second, we embed a PV restart scheme into the cGA where the PV is reset to a previously recorded value when no improvement can be obtained within a given number of consecutive generations. Third, we design a problem-specific local search operator that improves each feasible solution obtained by the cGA. Experimental results demonstrate that all the adopted improvement schemes contribute to an enhanced performance of our cGA. In addition, the proposed cGA is superior to some existing evolutionary algorithms in terms of both exploration and exploitation simultaneously in reduced computational time.\",\n \"Title: Case-Based Reasoning in Course Timetabling: An Attribute Graph Approach\\nYear: 2001\\n\\nAbstract: An earlier Case-based Reasoning (CBR) approach developed by the authors for educational course timetabling problems employed structured cases to represent the complex relationships between courses. The retrieval searches for structurally similar cases in the case base. In this paper, the approach is further developed to solve a wider range of problems. We also attempt to retrieve those cases that have common similar structures with some differences. Costs that are assigned to these differences have an input upon the similarity measure. A large number of experiments are performed consisting of different randomly produced timetabling problems and the results presented here strongly indicate that a CBR approach could provide a significant step forward in the development of automated systems to solve difficult timetabling problems. They show that using relatively little effort, we can retrieve these structurally similar cases to provide high quality timetables for new timetabling problems.\",\n \"Title: A Pareto-based search methodology for multi-objective nurse scheduling.\\nYear: 2012\\n\\nAbstract: In this paper, we propose a search technique for nurse scheduling, which deals with it as a multi-objective problem. For each nurse, we first randomly generate a set of legal shift patterns which satisfy all shift-related hard constraints. We then employ an adaptive heuristic to quickly find a solution with the least number of violations on the coverage-related hard constraint by assigning one of the available shift patterns of each nurse. Next, we apply a coverage repairing procedure to make the resulting solution feasible, by adding/removing any under-covered/over-covered shifts. Finally, to satisfy the soft constraints (or preferences), we present a simulated annealing based search method with the following two options: one with a weighted-sum evaluation function which encourages moves towards users’ predefined preferences, and another one with a domination-based evaluation function which encourages moves towards a more diversified approximated Pareto set. Computational results demonstrate that the proposed technique is applicable to modern hospital environments.\",\n \"Title: Hybrid variable neighbourhood approaches to university exam timetabling\\nYear: 2010\\n\\nAbstract: In this paper, we investigate variable neighbourhood search (VNS) approaches for the university examination timetabling problem. In addition to a basic VNS method, we introduce variants of the technique with different initialisation methods including a biased VNS and its hybridisation with a Genetic Algorithm. A number of different neighbourhood structures are analysed. It is demonstrated that the proposed technique is able to produce high quality solutions across a wide range of benchmark problem instances. In particular, we demonstrate that the Genetic Algorithm, which intelligently selects appropriate neighbourhoods to use within the biased VNS, produces the best known results in the literature, in terms of solution quality, on some of the benchmark instances. However, it requires relatively large amount of computational time. Possible extensions to this overall approach are also discussed.\",\n \"Title: Knowledge Discovery in a Hyper-heuristic for Course Timetabling Using Case-Based Reasoning\\nYear: 2002\\n\\nAbstract: This paper presents a new hyper-heuristic method using Case-Based Reasoning (CBR) for solving course timetabling problems. The term hyper-heuristics has recently been employed to refer to \\\"heuristics that choose heuristics\\\" rather than heuristics that operate directly on given problems. One of the overriding motivations of hyper-heuristic methods is the attempt to develop techniques that can operate with greater generality than is currently possible. The basic idea behind this is that we maintain a case base of information about the most successful heuristics for a range of previous timetabling problems to predict the best heuristic for the new problem in hand using the previous knowledge. Knowledge discovery techniques axe used to carry out the training on the CBR system to improve the system performance on the prediction. Initial results presented in this paper are good and we conclude by discussing the considerable promise for future work in this area.\",\n \"Title: Multiple-Retrieval Case-Based Reasoning for Course Timetabling Problems\\nYear: 2006\\n\\nAbstract: The structured representation of cases by attribute graphs in a Case-Based Reasoning (CBR) system for course timetabling has been the subject of previous research by the authors. In that system, the case base is organised as a decision tree and the retrieval process chooses those cases which are sub attribute graph isomorphic to the new case. The drawback of that approach is that it is not suitable for solving large problems. This paper presents a multiple-retrieval approach that partitions a large problem into small solvable sub-problems by recursively inputting the unsolved part of the graph into the decision tree for retrieval. The adaptation combines the retrieved partial solutions of all the partitioned sub-problems and employs a graph heuristic method to construct the whole solution for the new case. We present a methodology which is not dependant upon problem specific information and which, as such, represents an approach which underpins the goal of building more general timetabling systems. We explore the question of whether this multiple-retrieval CBR could be an effective initialisation method for local search methods such as Hill Climbing, Tabu Search and Simulated Annealing. Significant results are obtained from a wide range of experiments. An evaluation of the CBR system is presented and the impact of the approach on timetabling research is discussed. We see that the approach does indeed represent an effective initialisation method for these approaches.\",\n \"Title: Analysis Of Backtracking In University Examination Scheduling\\nYear: 2013\\n\\nAbstract: Simulation modelling of the initial assignments of exams to time-slots provides an alternative approach to the establishment of a set of feasible solutions that are subsequently optimized. In this research, we analyze two backtracking strategies for reassigning exams after the initial allocation of exams to time-slots. We propose two approaches for backtracking, BT1 and BT2. The study indicates that backtracking is an effective approach for improving the quality of the examination schedule where BT2 has outperformed BT1 in a number of cases.\",\n \"Title: Investigating a hybrid metaheuristic for job shop rescheduling\\nYear: 2007\\n\\nAbstract: Previous research has shown that artificial immune systems can be used to produce robust schedules in a manufacturing environment. The main goal is to develop building blocks (antibodies) of partial schedules that can be used to construct backup solutions (antigens) when disturbances occur during production. The building blocks are created based upon underpinning ideas from artificial immune systems and evolved using a genetic algorithm (Phase I). Each partial schedule (antibody) is assigned a fitness value and the best partial schedules are selected to be converted into complete schedules (antigens). We further investigate whether simulated annealing and the great deluge algorithm can improve the results when hybridised with our artificial immune system (Phase II). We use ten fixed solutions as our target and measure how well we cover these specific scenarios.\",\n \"Title: Roulette Wheel Graph Colouring for Solving Examination Timetabling Problems\\nYear: 2009\\n\\nAbstract: This work presents a simple graph based heuristic that employs a roulette wheel selection mechanism for solving exam timetabling problems. We arrange exams in non-increasing order of the number of conflicts (degree) that they have with other exams. The difficulty of each exam to be scheduled is estimated based on the degree of exams in conflict. The degree determines the size of a segment in a roulette wheel, with a larger degree giving a larger segment. The roulette wheel selection mechanism selects an exam if the generated random number falls within the exam's segment. This overcomes the problem of repeatedly choosing and scheduling the same sequence of exams. We utilise the proposed Roulette Wheel Graph Colouring heuristic on the un-capacitated Carter's benchmark datasets. Results showed that this simple heuristic is capable of producing feasible solutions for all 13 instances.\",\n \"Title: A Hybrid Constraint Programming Approach for Nurse Rostering Problems\\nYear: 2008\\n\\nAbstract: Due to the complexity of nurse rostering problems (NRPs), Constraint Programming (CP) approaches on their own have shown to be ineffective in solving these highly constrained problems. We investigate a two-stage hybrid CP approach on real world benchmark NRPs. In the first stage, a constraint satisfaction model is used to generate weekly rosters consist of high quality shift sequences satisfying a subset of constraints. An iterative forward search is then adapted to extend them to build complete feasible solutions. Variable and value selection heuristics are employed to improve the efficiency. In the second stage, a simple Variable Neighborhood Search is used to quickly improve the solution obtained. The basic idea of the hybrid approach is based on the observations that high quality nurse rosters consist of high quality shift sequences. By decomposing the problems into solvable sub-problems for CP, the search space of the original problems are significantly reduced. The results on benchmark problems demonstrate the efficiency of this hybrid CP approach when compared to the state-of-the-art approaches in the literature.\",\n \"Title: Adaptive selection of heuristics for assigning time slots and rooms in exam timetables\\nYear: 2013\\n\\nAbstract: This paper presents an iterative adaptive approach which hybridises bin packing heuristics to assign exams to time slots and rooms. The approach combines a graph-colouring heuristic, to select an exam in every iteration, with bin-packing heuristics to automate the process of time slot and room allocation for exam timetabling problems. We start by analysing the quality of the solutions obtained by using one heuristic at a time. Depending on the individual performance of each heuristic, a random iterative hyper-heuristic is used to randomly hybridise the heuristics and produce a collection of heuristic sequences to construct solutions with different quality. Based on these sequences, we analyse the way in which the bin packing heuristics are automatically hybridised. It is observed that the performance of the heuristics used varies depending on the problem. Based on these observations, an iterative hybrid approach is developed to adaptively choose and hybridise the heuristics during solution construction. The overall aim here is to automate the heuristic design process, which draws upon an emerging research theme which is concerned with developing methods to design and adapt heuristics automatically. The approach is tested on the exam timetabling track of the second International Timetabling Competition, to evaluate its ability to generalise on instances with different features. The hyper-heuristic with low-level graph-colouring and bin-packing heuristics approach was found to generalise well over all the problem instances and performed comparably to the state of the art approaches.\",\n \"Title: Hybridizations within a graph-based hyper-heuristic framework for university timetabling problems\\nYear: 2009\\n\\nAbstract: A significant body of literature has explored various research directions in hyper-heuristics (which can be thought as heuristics to choose heuristics). In this paper we define a graph based hyper-heuristic (GHH) framework and compare the performance of a number of local search based searching algorithms as the high level heuristics. They are used to search upon permutations of low level graph heuristics rather than solutions within the GHH framework. We also investigate efficient hybridisations between the GHH and local search methods. Aiming at gaining an in-depth understanding on this new technique, we address and discuss the fundamental issues concerning the neighborhood structures, the characteristics of the two search spaces (namely the search spaces of the graph heuristics and the actual solutions). Issues of exploring by the high level search and exploiting by the local search within the hy- brid GHH are also addressed. These, to our knowledge, are entirely novel directions in hyper-heuristics. The comparisons among different high level heuristics within the unified framework suggest that the role high level search play is to explore as wide search space as possible within a limited time using simple and iterative methods. The efficient hybridisations within the GHH obtained competitive results compared with the best published results for both benchmark course and exam timetabling problems, demonstrating its efficiency and generality. Possible extensions upon this simple yet general graph based hyper-heuristic are also provided.\",\n \"Title: Solving a practical examination timetabling problem: a case study\\nYear: 2007\\n\\nAbstract: This paper presents a Greedy-Least Saturation Degree (G-LSD) heuristic (which is an adaptation of the least saturation degree heuristic) to solve a real-world examination timetabling problem at the University Kebangsaan, Malaysia. We utilise a new objective function that was proposed in our previous work to evaluate the quality of the timetable. The objective function considers both timeslots and days in assigning exams to timeslots, where higher priority is given to minimise students having consecutive exams on the same day. The objective also tries to spread exams throughout the examination period. This heuristic has the potential to be used for the benchmark examination datasets (e.g. the Carter datasets) as well as other real world problems. Computational results are presented.\",\n \"Title: A nondominated sorting genetic algorithm for bi-objective network coding based multicast routing problems\\nYear: 2013\\n\\nAbstract: Network coding is a new communication technique that generalizes routing, where, instead of simply forwarding the packets they receive, intermediate nodes are allowed to recombine (code) together some of the data packets received from different incoming links if necessary. By doing so, the maximum information flow in a network can always be achieved. However, performing coding operations (i.e. recombining data packets) incur computational overhead and delay of data processing at the corresponding nodes. In this paper, we investigate the optimization of the network coding based multicast routing problem with respect to two widely considered objectives, i.e. the cost and the delay. In general, reducing cost can result into a cheaper multicast solution for network service providers, while decreasing delay improves the service quality for users. Hence we model the problem as a bi-objective optimization problem to minimize the total cost and the maximum transmission delay of a multicast. This bi-objective optimization problem has not been considered in the literature. We adapt the Elitist Nondominated Sorting Genetic Algorithm (NSGA-II) for the new problem by introducing two adjustments. As there are many infeasible solutions in the search space, the first adjustment is an initialization scheme to generate a population of feasible and diversified solutions. These initial solutions help to guide the search towards the Pareto-optimal front. In addition, the original NSGA-II is very likely to produce a number of solutions with identical objective values at each generation, which may seriously deteriorate the level of diversity and the optimization performance. The second adjustment is an individual delegate scheme where, among those solutions with identical objective values, only one of them is retained in the population while the others are deleted. Experimental results reveal that each adopted adjustment contributes to the adaptation of NSGA-II for the problem concerned. Moreover, the adjusted NSGA-II outperforms a number of state-of-the-art multiobjective evolutionary algorithms with respect to the quality of the obtained nondominated solutions in the conducted experiments.\",\n \"Title: A graph-based hyper-heuristic for educational timetabling problems\\nYear: 2007\\n\\nAbstract: This paper presents an investigation of a simple generic hyper-heuristic approach upon a set of widely used constructive heuristics (graph coloring heuristics) in timetabling. Within the hyper-heuristic framework, a tabu search approach is employed to search for permutations of graph heuristics which are used for constructing timetables in exam and course timetabling problems. This underpins a multi-stage hyper-heuristic where the tabu search employs permutations upon a different number of graph heuristics in two stages. We study this graph-based hyper-heuristic approach within the context of exploring fundamental issues concerning the search space of the hyper-heuristic (the heuristic space) and the solution space. Such issues have not been addressed in other hyper-heuristic research. These approaches are tested on both exam and course benchmark timetabling problems and are compared with the fine-tuned bespoke state-of-the-art approaches. The results are within the range of the best results reported in the literature. The approach described here represents a significantly more generally applicable approach than the current state of the art in the literature. Future work will extend this hyper-heuristic framework by employing methodologies which are applicable on a wider range of timetabling and scheduling problems.\",\n \"Title: A population based incremental learning for delay constrained network coding resource minimization\\nYear: 2011\\n\\nAbstract: In network coding based multicast, coding operations are expected to be minimized as they not only incur additional computational cost at corresponding nodes in network but also increase data transmission delay. On the other hand, delay constraint must be concerned particularly in delay sensitive applications, e.g. video conferencing. In this paper, we study the problem of minimizing the amount of coding operations required while meeting the end-to-end delay constraint in network coding based multicast. A population based incremental learning (PBIL) algorithm is developed, where a group of best so far individuals, rather than a single one, is maintained and used to update the probability vector, which enhances the global search capability of the algorithm. Simulation results demonstrate the effectiveness of our PBIL.\",\n \"Title: Setting the Research Agenda in Automated Timetabling: The Second International Timetabling Competition\\nYear: 2010\\n\\nAbstract: The Second International Timetabling Competition (TTC2007) opened in August 2007. Building on the success of the first competition in 2002, this sequel aimed to further develop research activity in the area of educational timetabling. The broad aim of the competition was to create better understanding between researchers and practitioners by allowing emerging techniques to be developed and tested on real-world models of timetabling problems. To support this, a primary goal was to provide researchers with models of problems faced by practitioners through incorporating a significant number of real-world constraints. Another objective of the competition was to stimulate debate within the widening timetabling research community. The competition was divided into three tracks to reflect the important variations that exist in educational timetabling within higher education. Because these formulations incorporate an increased number of “real-world” issues, it is anticipated that the competition will now set the research agenda within the field. After finishing in January 2008, final results were made available in May 2008. Along with background to the competition, the competition tracks are described here along with a brief overview of the techniques used by the competition winners.\",\n \"Title: A Task Based Approach For A Real-World Commodity Routing Problem\\nYear: 2013\\n\\nAbstract: In this paper, a real world short-haul commodity routing problem is presented. This problem shares several similarities with vehicle routing problem with time windows (VRPTW) and the service network design problem (SNDP), but also has its own specific structures that do not exist in VRPTW or SNDP. A task based formulation is developed for this problem and a variable neighbourhood search metaheuristic approach is proposed, resulting in a visible improvement over the original routing plans according to experimental tests over three real-life instances. Apart from introducing a new real-world commodity routing problem, another main contribution of this paper is a task based formulation that allows commodity flows being considered as nodes in a routing network. Thus algorithms that were designed for VRPTW or SDVRP can also possibly be adapted to solve this commodity flow problem.\",\n \"Title: Supply chain coordination with dual procurement sources via real-option contract\\nYear: 2015\\n\\nAbstract: We explore the manufacturer's optimal procurement strategy under stochastic demand.The manufacturer purchases from the supplier and the existing spot markets.The manufacturer maneuvers the real-option to coordinate the supply chain.Effects of risks in the spot market on market equilibrium are derived. In a two-stage supply chain with a supplier and a manufacturer, the manufacturer can purchase a product either from the supplier or in the spot market. The spot market, however, inevitably involves price fluctuation risk and supply risk. Assuming that the manufacturer is the leader in a procurement game and offers a real-option contract to the supplier, we study the manufacturer's optimal mixed procurement strategy that integrates the use of the real-option contract and the spot market. Moreover, we analyze the effects of the price risk and the supply risk in the spot market on market equilibrium. We show that using the real-option contract mechanism improves the overall expected profit of a supply chain and guarantees supply chain coordination in the presence of the spot market. The results also demonstrate that the price risk and the supply risk in the spot market adversely affect the manufacturer's expected profit. On the contrary, these two risks bring benefits to the supplier.\",\n \"Title: A dynamic multiarmed bandit-gene expression programming hyper-heuristic for combinatorial optimization problems.\\nYear: 2015\\n\\nAbstract: Hyper-heuristics are search methodologies that aim to provide high-quality solutions across a wide variety of problem domains, rather than developing tailor-made methodologies for each problem instance/domain. A traditional hyper-heuristic framework has two levels, namely, the high level strategy (heuristic selection mechanism and the acceptance criterion) and low level heuristics (a set of problem specific heuristics). Due to the different landscape structures of different problem instances, the high level strategy plays an important role in the design of a hyper-heuristic framework. In this paper, we propose a new high level strategy for a hyper-heuristic framework. The proposed high-level strategy utilizes a dynamic multiarmed bandit-extreme value-based reward as an online heuristic selection mechanism to select the appropriate heuristic to be applied at each iteration. In addition, we propose a gene expression programming framework to automatically generate the acceptance criterion for each problem instance, instead of using human-designed criteria. Two well-known, and very different, combinatorial optimization problems, one static (exam timetabling) and one dynamic (dynamic vehicle routing) are used to demonstrate the generality of the proposed framework. Compared with state-of-the-art hyper-heuristics and other bespoke methods, empirical results demonstrate that the proposed framework is able to generalize well across both domains. We obtain competitive, if not better results, when compared to the best known results obtained from other methods that have been presented in the scientific literature. We also compare our approach against the recently released hyper-heuristic competition test suite. We again demonstrate the generality of our approach when we compare against other methods that have utilized the same six benchmark datasets from this test suite.\",\n \"Title: A learning-guided multi-objective evolutionary algorithm for constrained portfolio optimization.\\nYear: 2014\\n\\nAbstract: Portfolio optimization involves the optimal assignment of limited capital to different available financial assets to achieve a reasonable trade-off between profit and risk objectives. In this paper, we studied the extended Markowitz's mean-variance portfolio optimization model. We considered the cardinality, quantity, pre-assignment and round lot constraints in the extended model. These four real-world constraints limit the number of assets in a portfolio, restrict the minimum and maximum proportions of assets held in the portfolio, require some specific assets to be included in the portfolio and require to invest the assets in units of a certain size respectively. An efficient learning-guided hybrid multi-objective evolutionary algorithm is proposed to solve the constrained portfolio optimization problem in the extended mean-variance framework. A learning-guided solution generation strategy is incorporated into the multi-objective optimization process to promote the efficient convergence by guiding the evolutionary search towards the promising regions of the search space. The proposed algorithm is compared against four existing state-of- the-art multi-objective evolutionary algorithms, namely Non-dominated Sorting Genetic Algorithm ( NSGA-II), Strength Pareto Evolutionary Algorithm (SPEA-2), Pareto Envelope-based Selection Algorithm (PESA-II) and Pareto Archived Evolution Strategy (PAES). Computational results are reported for publicly available OR-library datasets from seven market indices involving up to 1318 assets. Experimental results on the constrained portfolio optimization problem demonstrate that the proposed algorithm significantly outperforms the four well-known multi-objective evolutionary algorithms with respect to the quality of obtained efficient frontier in the conducted experiments. (C) 2014 The Authors. Published by Elsevier B.V.\",\n \"Title: Search with evolutionary ruin and stochastic rebuild: A theoretic framework and a case study on exam timetabling.\\nYear: 2015\\n\\nAbstract: •This paper presents a new search method which tries to learn and adapt to the changing environments during the search.•It improves the original R&R idea by implementing a phase of Evolutionary Ruin to mimic an evolution within single solutions.•It achieves optimisation by an iterative process of component evaluation, solution disruption and stochastic constructive repair.•It presents a formal framework and implements a Markov chain analysis on some theoretical properties of the approach.•Experimental results on exam timetabling benchmark problems have demonstrated the strength of the approach.\",\n \"Title: A two-stage stochastic mixed-integer program modelling and hybrid solution approach to portfolio selection problems.\\nYear: 2014\\n\\nAbstract: In this paper, we investigate a multi-period portfolio selection problem with a comprehensive set of real-world trading constraints as well as market random uncertainty in terms of asset prices. We formulate the problem into a two-stage stochastic mixed-integer program (SMIP) with recourse. The set of constraints is modelled as mixed-integer program, while a set of decision variables to rebalance the portfolio in multiple periods is explicitly introduced as the recourse variables in the second stage of stochastic program. Although the combination of stochastic program and mixed-integer program leads to computational challenges in finding solutions to the problem, the proposed SMIP model provides an insightful and flexible description of the problem. The model also enables the investors to make decisions subject to real-world trading constraints and market uncertainty.\",\n \"Title: Network flow models for intraday personnel scheduling problems.\\nYear: 2014\\n\\nAbstract: Personnel scheduling problems can be decomposed into two stages. In the first stage for each employee the working days have to be fixed. In the second stage for each day of the planning period an intraday scheduling problem has to be solved. It consists of the assignment of shifts to the employees who have to work on the day and for each working period of an employee a task assignment such that the demand of all tasks for personnel is covered. In Robinson et al. (Burke and Trick (Eds.), Proceedings of the 5th International Conference on the Practice and Theory of Automated Timetabling, 18th August–20th August 2004, Pittsburgh, PA, USA, pp. 561–566, ), the intraday problem has been formulated as a maximum flow problem. The assumptions are that, employees are qualified for all tasks, their shifts are given, and they are allowed to change tasks during the day.In this work, we extend the network flow model to cover the case where not all employees are qualified to perform all tasks. The model is further extended to be able to calculate shifts of employees for the given day, assuming that an earliest starting time, a latest finishing time, and a minimal working time are given. Labour cost can be also taken into account by solving a minimum cost network flow problem.\",\n \"Title: Adaptive selection of heuristics for improving exam timetables.\\nYear: 2014\\n\\nAbstract: This paper presents a hyper-heuristic approach which hybridises low-level heuristic moves to improve timetables. Exams which cause a soft-constraint violation in the timetable are ordered and rescheduled to produce a better timetable. It is observed that both the order in which exams are rescheduled and the heuristic moves used to reschedule the exams and improve the timetable affect the quality of the solution produced. After testing different combinations in a hybrid hyper-heuristic approach, the Kempe chain move heuristic and time-slot swapping heuristic proved to be the best heuristic moves to use in a hybridisation. Similarly, it was shown that ordering the exams using Saturation Degree and breaking any ties using Largest Weighted Degree produce the best results. Based on these observations, a methodology is developed to adaptively hybridise the Kempe chain move and timeslot swapping heuristics in two stages. In the first stage, random heuristic sequences are generated and automatically analysed. The heuristics repeated in the best sequences are fixed while the rest are kept empty. In the second stage, sequences are generated by randomly assigning heuristics to the empty positions in an attempt to find the best heuristic sequence. Finally, the generated sequences are applied to the problem. The approach is tested on the Toronto benchmark and the exam timetabling track of the second International Timetabling Competition, to evaluate its generality. The hyper-heuristic with low-level improvement heuristics approach was found to generalise well over the two different datasets and performed comparably to the state of the art approaches.\",\n \"Title: Hybridising heuristics within an estimation distribution algorithm for examination timetabling\\nYear: 2015\\n\\nAbstract: This paper presents a hybrid hyper-heuristic approach based on estimation distribution algorithms. The main motivation is to raise the level of generality for search methodologies. The objective of the hyper-heuristic is to produce solutions of acceptable quality for a number of optimisation problems. In this work, we demonstrate the generality through experimental results for different variants of exam timetabling problems. The hyper-heuristic represents an automated constructive method that searches for heuristic choices from a given set of low-level heuristics based only on non-domain-specific knowledge. The high-level search methodology is based on a simple estimation distribution algorithm. It is capable of guiding the search to select appropriate heuristics in different problem solving situations. The probability distribution of low-level heuristics at different stages of solution construction can be used to measure their effectiveness and possibly help to facilitate more intelligent hyper-heuristic search methods.\",\n \"Title: On minimizing coding operations in network coding based multicast: an evolutionary algorithm\\nYear: 2014\\n\\nAbstract: In telecommunications networks, to enable a valid data transmission based on network coding, any intermediate node within a given network is allowed, if necessary, to perform coding operations. The more coding operations needed, the more coding resources consumed and thus the more computational overhead and transmission delay incurred. This paper investigates an efficient evolutionary algorithm to minimize the amount of coding operations required in network coding based multicast. Based on genetic algorithms, we adapt two extensions in the proposed evolutionary algorithm, namely a new crossover operator and a neighbourhood search operator, to effectively solve the highly complex problem being concerned. The new crossover is based on logic OR operations to each pair of selected parent individuals, and the resulting offspring are more likely to become feasible. The aim of this operator is to intensify the search in regions with plenty of feasible individuals. The neighbourhood search consists of two moves which are based on greedy link removal and path reconstruction, respectively. Due to the specific problem feature, it is possible that each feasible individual corresponds to a number of, rather than a single, valid network coding based routing subgraphs. The neighbourhood search is applied to each feasible individual to find a better routing subgraph that consumes less coding resource. This operator not only improves solution quality but also accelerates the convergence. Experiments have been carried out on a number of fixed and randomly generated benchmark networks. The results demonstrate that with the two extensions, our evolutionary algorithm is effective and outperforms a number of state-of-the-art algorithms in terms of the ability of finding optimal solutions.\",\n \"Title: A path-oriented encoding evolutionary algorithm for network coding resource minimization.\\nYear: 2014\\n\\nAbstract: Network coding is an emerging telecommunication technique, where any intermediate node is allowed to recombine incoming data if necessary. This technique helps to increase the throughput, however, very likely at the cost of huge amount of computational overhead, due to the packet recombination performed (ie coding operations). Hence, it is of practical importance to reduce coding operations while retaining the benefits that network coding brings to us. In this paper, we propose a novel evolutionary algorithm (EA) to minimize the amount of coding operations involved. Different from the state-of-the-art EAs which all use binary encodings for the problem, our EA is based on path-oriented encoding. In this new encoding scheme, each chromosome is represented by a union of paths originating from the source and terminating at one of the receivers. Employing path-oriented encoding leads to a search space where all solutions are feasible, which fundamentally facilitates more efficient search of EAs. Based on the new encoding, we develop three basic operators, that is, initialization, crossover and mutation. In addition, we design a local search operator to improve the solution quality and hence the performance of our EA. The simulation results demonstrate that our EA significantly outperforms the state-of-the-art algorithms in terms of global exploration and computational time.\",\n \"Title: A Population-Based Incremental Learning Method for Constrained Portfolio Optimisation\\nYear: 2014\\n\\nAbstract: This paper investigates a hybrid algorithm which utilizes exact and heuristic methods to optimise asset selection and capital allocation in portfolio optimisation. The proposed method is composed of a customised population based incremental learning procedure and a mathematical programming application. It is based on the standard Markowitz model with additional practical constraints such as cardinality on the number of assets and quantity of the allocated capital. Computational experiments have been conducted and analysis has demonstrated the performance and effectiveness of the proposed approach.\",\n \"Title: Vehicle Routing in a Forestry Commissioning Operation Using Ant Colony Optimisation.\\nYear: 2014\\n\\nAbstract: This paper formulates a vehicle routing problem where constraints have been produced from a real world forestry commissioning dataset. In the problem, vehicles are required to fully load wood from forests and then deliver the wood to sawmills. The constraints include time windows and loading bay constraints at forests and sawmills. The loading bay constraints are examples of inter-route constraints that have not been studied in the literature as much as intra-route constraints. Inter-route constraints are constraints that cause dependencies between vehicles such that more than one vehicle is required to perform a task. Some locations have a lot of consignments at similar times, causing vehicles to queue for loading bays. The aim is to produce an optimal routing of consignments for vehicles such that the total time is minimised and there is as little queuing at forests and sawmills as possible. In this paper, the problem has been formulated into a vehicle routing problem with time windows and extra inter-route constraints. An ant colony optimisation heuristic is applied to the datasets and yields feasible solutions that appropriately use the loading bays. A number of methods of handling the inter-route constraints are also tested. It is shown that incorporating the delay times at loading bays into the ant's visibility produces solutions with the best objective values.\",\n \"Title: New Solution for a Benchmark Nurse Scheduling Problem Using Integer Programming\\nYear: 2014\\n\\nAbstract: In this paper, we formulate nurse scheduling problem in modern hospital environment as an integer programming (IP) problem. We simplify the nurse scheduling problem by transforming it through Information Granulation which enables the original problem to be expressed and solved more easily. The solution of the simplified problem is followed by a refinement of this solution to ensure that all constraints of the original problem are taken into account. We have used the GNU Octave, open source mathematical modelling and simulation software for Windows to solve the simplified problem expressed as Integer Programming problem. We used the branch and bound and dual simplex version of the integer programming solver. Very promising results from the real life benchmark problem sets are reported and are compared to the results reported in the literature. Results show that the proposed algorithm facilitates computation of feasible schedules in a short time. We suggest that the proposed methodology can be applied to other resource allocation problems with a large number of constraints.\",\n \"Title: Automatic Design of a Hyper-Heuristic Framework With Gene Expression Programming for Combinatorial Optimization Problems\\nYear: 2015\\n\\nAbstract: Hyper-heuristic approaches aim to automate heuristic design in order to solve multiple problems instead of designing tailor-made methodologies for individual problems. Hyper-heuristics accomplish this through a high-level heuristic (heuristic selection mechanism and an acceptance criterion). This automates heuristic selection, deciding whether to accept or reject the returned solution. The fact that different problems, or even instances, have different landscape structures and complexity, the design of efficient high-level heuristics can have a dramatic impact on hyper-heuristic performance. In this paper, instead of using human knowledge to design the high-level heuristic, we propose a gene expression programming algorithm to automatically generate, during the instance-solving process, the high-level heuristic of the hyper-heuristic framework. The generated heuristic takes information (such as the quality of the generated solution and the improvement made) from the current problem state as input and decides which low-level heuristic should be selected and the acceptance or rejection of the resultant solution. The benefit of this framework is the ability to generate, for each instance, different high-level heuristics during the problem-solving process. Furthermore, in order to maintain solution diversity, we utilize a memory mechanism that contains a population of both high-quality and diverse solutions that is updated during the problem-solving process. The generality of the proposed hyper-heuristic is validated against six well-known combinatorial optimization problems, with very different landscapes, provided by the HyFlex software. Empirical results, comparing the proposed hyper-heuristic with state-of-the-art hyper-heuristics, conclude that the proposed hyper-heuristic generalizes well across all domains and achieves competitive, if not superior, results for several instances on all domains.\",\n \"Title: Grammatical Evolution Hyper-Heuristic for Combinatorial Optimization Problems\\nYear: 2013\\n\\nAbstract: Designing generic problem solvers that perform well across a diverse set of problems is a challenging task. In this work, we propose a hyper-heuristic framework to automatically generate an effective and generic solution method by utilizing grammatical evolution. In the proposed framework, grammatical evolution is used as an online solver builder, which takes several heuristic components (e.g., different acceptance criteria and different neighborhood structures) as inputs and evolves templates of perturbation heuristics. The evolved templates are improvement heuristics, which represent a complete search method to solve the problem at hand. To test the generality and the performance of the proposed method, we consider two well-known combinatorial optimization problems: exam timetabling (Carter and ITC 2007 instances) and the capacitated vehicle routing problem (Christofides and Golden instances). We demonstrate that the proposed method is competitive, if not superior, when compared to state-of-the-art hyper-heuristics, as well as bespoke methods for these different problem domains. In order to further improve the performance of the proposed framework we utilize an adaptive memory mechanism, which contains a collection of both high quality and diverse solutions and is updated during the problem solving process. Experimental results show that the grammatical evolution hyper-heuristic, with an adaptive memory, performs better than the grammatical evolution hyper-heuristic without a memory. The improved framework also outperforms some bespoke methodologies, which have reported best known results for some instances in both problem domains.\",\n \"Title: Sparse Double-Geometric Nonlocal Mean image recovery via steerable kernel\\nYear: 2015\\n\\nAbstract: It has been proved that the geometric information in images produce most stimulus of human eyes, which is important for the image recovery. However, the local geometric structure in images are too diverse to be accurately captured. Recent decade has witnessed a flourish of biological inspired algorithms in the image recovery. In this paper, inspired the adaptive and sparse characteristic of visual perception of humans, we advance an adaptive steerable kernel based Sparse Double-Geometric Nonlocal Mean (SDGNLM) denoising algorithm by exploring the local geometric information in both the \\\\\\\"neighbor location\\\\\\\" and \\\\\\\"similarity measure\\\\\\\". In our method, a steerable kernel is employed to reveal the local geometric information of pixels, and sparse assumption of neighbors is cast on pixels to achieve more accurate image recovery. Moreover, a weighted sparse optimization algorithm is proposed to find and weight neighbors having the similar characteristics with each pixel. Some experiments are taken on some benchmark natural images, and the experimental results demonstrate its superiorities to NLM algorithm and its variants, in terms of both visual results and numerical guidelines.\",\n \"Title: An Improved MOEA/D for QoS Oriented Multimedia Multicasting with Network Coding.\\nYear: 2015\\n\\nAbstract: Recent years witness a significant growth in multimedia applications. Among them, a stream of applications is real-time and requires one-to-many fast data transmission with stringent quality-of-service (QoS) requirements, where multicast is an important supporting technology. In particular, with more and more mobile end users requesting real-time broadband multimedia applications, it is of vital importance to provide them with satisfied quality of experience. As network coding can offer higher bandwidth to users and accommodate more flows for networks than traditional routing, this paper studies the multicast routing problem with network coding and formulates it as a multi-objective optimization problem. As delay and packet loss ratio (PLR) are two important performance indicators for QoS, we consider them as the two objectives for minimization. To address the problem above, we present a multi-objective evolutionary algorithm based on decomposition (MOEA/D), where an all population updating rule is devised to address the problem of lacking feasible solutions in the search space. Experimental results demonstrate the effectiveness of the proposed algorithm and it outperforms a number of state-of-the-art algorithms.\",\n \"Title: Good Laboratory Practice for optimization research.\\nYear: 2016\\n\\nAbstract: Good Laboratory Practice has been a part of non-clinical research for over 40 years. Optimization Research, despite having many papers discussing standards being published over the same period of time, has yet to embrace standards that underpin its research. In this paper we argue the need to adopt standards in optimization research. Building on previous papers, many of which have suggested that the optimization research community should adopt certain standards, we suggest a concrete set of recommendations that the community should adopt. We also discuss how the proposals in this paper could be progressed.Keywords: optimization, operations research, reproducibility\",\n \"Title: A Hybrid Genetic Algorithm For A Two-Stage Stochastic Portfolio Optimization With Uncertain Asset Prices\\nYear: 2015\\n\\nAbstract: Portfolio optimization is one of the most important problems in the finance field. The traditional mean-variance model has its drawbacks since it fails to take the market uncertainty into account. In this work, we investigate a two-stage stochastic portfolio optimization model with a comprehensive set of real world trading constraints in order to capture the market uncertainties in terms of future asset prices. A hybrid approach, which integrates genetic algorithm (GA) and a linear programming (LP) solver is proposed in order to solve the model, where GA is used to search for the assets selection heuristically and the LP solver solves the corresponding sub-problems of weight allocation optimally. Scenarios are generated to capture uncertain prices of assets for five benchmark market instances. The computational results indicate that the proposed hybrid algorithm can obtain very promising solutions. Possible future research directions are also discussed.\",\n \"Title: A Modified Ant Colony Optimization Algorithm for Network Coding Resource Minimization.\\nYear: 2016\\n\\nAbstract: This paper presents a modified ant colony optimization (ACO) approach for the network coding resource minimization problem. It is featured with several attractive mechanisms specially devised for solving the concerned problem: 1) a multidimensional pheromone maintenance mechanism is put forward to address the issue of pheromone overlapping; 2) problem-specific heuristic information is employed to ...\",\n \"Title: Constrained Portfolio Optimisation: The State-of-the-Art Markowitz Models.\\nYear: 2016\\n\\nAbstract: This paper studies the state-of-art constrained portfolio optimisation models, using exact solver to identify the optimal solutions or lower bound for the benchmark instances at the OR-library with extended constraints. The effects of pre-assignment, round-lot, and class constraints based on the quantity and cardinality constrained Markowitz model are firstly investigated to gain insights of increased problem difficulty, followed by the analysis of various constraint settings including those mostly studied in the literature. The study aims to provide useful guidance for future investigations in computational algorithms\",\n \"Title: A Variable Neighbourhood Search Algorithm with Compound Neighbourhoods for VRPTW.\\nYear: 2016\\n\\nAbstract: The Vehicle Routing Problem with Time Windows (VRPTW) consists of constructing least cost routes from a depot to a set of geographically scattered service points and back to the depot, satisfying service time interval and capacity constraints. A Variable Neighbourhood Search algorithm with Compound Neighbourhoods is proposed to solve VRPTW in this paper. A number of independent neighbourhood operators are composed into compound neighbourhood operators in a new way, to explore wider search area concerning two objectives (to minimize the number of vehicles and the total travel distance) simultaneously. Promising results are obtained on benchmark datasets\",\n \"Title: Towards an Efficient API for Optimisation Problems Data.\\nYear: 2016\\n\\nAbstract: The literature presents many application programming interfaces (APIs) and frameworks that provide state of the art algorithms and techniques for solving optimisation problems. The same cannot be said about APIs and frameworks focused on the problem data itself because with the peculiarities and details of each variant of a problem, it is virtually impossible to provide general tools that are broad enough to be useful on a large scale. However, there are benefits of employing problem-centred APIs in a R&D environment: improving the understanding of the problem, providing fairness on the results comparison, providing efficient data structures for different solving techniques, etc. Therefore, in this work we propose a novel design methodology for an API focused on an optimisation problem. Our methodology relies on a data parser to handle the problem specification files and on a set of efficient data structures to handle the information on memory, in an intuitive fashion for researchers and efficient for the solving algorithms. Also, we present the concepts of a solution dispenser that can manage solutions objects in memory better than built-in garbage collectors. Finally, we describe the positive results of employing a tailored API to a project involving the development of optimisation solutions for workforce scheduling and routing problems.\",\n \"Title: Hybridising Local Search With Branch-And-Bound For Constrained Portfolio Selection Problems\\nYear: 2016\\n\\nAbstract: In this paper, we investigate a constrained portfolio selection problem with cardinality constraint, minimum size and position constraints, and non-convex transaction cost. A hybrid method named Local Search Branch-and-Bound (LS-B&B) which integrates local search with B&B is proposed based on the property of the problem, i.e. cardinality constraint. To eliminate the computational burden which is mainly due to the cardinality constraint, the corresponding set of binary variables is identified as core variables. Variable fixing (Bixby, Fenelon et al. 2000) is applied on the core variables, together with a local search, to generate a sequence of simplified sub-problems. The default B&B search then solves these restricted and simplified sub-problems optimally due to their reduced size comparing to the original one. Due to the inherent similar structures in the sub-problems, the solution information is reused to evoke the repairing heuristics and thus accelerate the solving procedure of the sub-problems in B&B. The tight upper bound identified at early stage of the search can discard more sub-problems to speed up the LS-B&B search to the optimal solution to the original problem. Our study is performed on a set of portfolio selection problems with non-convex transaction costs and a number of trading constraints based on the extended mean-variance model. Computational experiments demonstrate the effectiveness of the algorithm by using less computational time.\",\n \"Title: A quantum inspired evolutionary algorithm for dynamic multicast routing with network coding\\nYear: 2016\\n\\nAbstract: This paper studies and models the multicast routing problem with network coding in dynamic network environment, where computational and bandwidth resources are to be jointly optimized. A quantum inspired evolutionary algorithm (QEA) is developed to address the problem above, where a restart scheme is devised for well adapting QEA for tracing the ever-changing optima in dynamic environment. Experimental results show that the proposed QEA outperforms a number of existing evolutionary algorithms in terms of the best solution obtained.\",\n \"Title: Mean-VaR portfolio optimization: A nonparametric approach.\\nYear: 2017\\n\\nAbstract: •Present a new MOEA for complex portfolio optimization.•Six real-world trading constraints are considered.•Computational experiments are performed by using real market data.•Results show the effectiveness of the learning mechanism.•Proposed method yield improved performance relative to existing methods.\",\n \"Title: An improved MOEA/D algorithm for multi-objective multicast routing with network coding.\\nYear: 2017\\n\\nAbstract: •Formulate a network-coding-based multicast routing problem with three objectives.•Propose a hybrid multi-objective evolutionary algorithm incorporating PBIL into MOEA/D.•Develop a probability-based initialization scheme, a population updating rule, and a reproduction operator.\",\n \"Title: A hybrid EDA for load balancing in multicast with network coding.\\nYear: 2017\\n\\nAbstract: •Model a load balancing optimization problem in the context of network coding based multicast in communication networks.•Propose a hybridized PBIL with two novel performance-improving schemes, namely the bi-probability-vector co-evolution scheme and the local search heuristic.•Experimental results demonstrate that the proposed algorithm outperforms a number of state-of-the-art evolutionary algorithms with respect to the solution quality.\",\n \"Title: Automated Design of Machine Learning and Search Algorithms [Guest Editorial].\\nYear: 2018\\n\\nAbstract: The three articles in this special section focus on the development of automated design of machine learning and search algorithms. There is a demand, especially from industry and business, to automate the design of machine learning and search algorithms, thereby removing the heavy reliance on human experts. Machine learning and search techniques play an important role in solving real-world complex...\",\n \"Title: Hybrid multi-objective evolutionary algorithms based on decomposition for wireless sensor network coverage optimization.\\nYear: 2018\\n\\nAbstract: •This paper models the coverage control optimization problem in WSN as a multi-objective optimization problem considering multiple objectives.•A hybrid reproduction operator based on Genetic Algorithm (GA) and Differential Evolution (DE) has been proposed to diversify the search.•An discrete binary particle swarm optimization method has been designed as the enhancement strategy to obtain a better Pareto solution set.•Large amount of experiments have been carried out to demonstrate the effectiveness of our proposed algorithms.\",\n \"Title: Course Recommendation Model in Academic Social Networks Based on Association Rules and Multi -similarity\\nYear: 2018\\n\\nAbstract: Compared with traditional course websites, the open online course platforms have a larger number of courses, and course recommendation is becoming increasingly important. In this paper, we shall propose a course recommendation model based on academic social networks, a hybrid method combing with association rules algorithm and an improved multi-similarity algorithm of multi-source information, which can recommend courses according to potential relationships between courses and users implicit interests. The proposed model is applied to SCHOLAT. Judging from our experimental results, the new model is capable of reducing cold-start problem and providing better accuracy.\",\n \"Title: A hyper-heuristic with two guidance indicators for bi-objective mixed-shift vehicle routing problem with time windows.\\nYear: 2018\\n\\nAbstract: In this paper, a Mixed-Shift Vehicle Routing Problem is proposed based on a real-life container transportation problem. In a long planning horizon of multiple shifts, transport tasks are completed satisfying the time constraints. Due to the different travel distances and time of tasks, there are two types of shifts (long shift and short shift) in this problem. The unit driver cost for long shifts is higher than that of short shifts. A mathematical model of this Mixed-Shift Vehicle Routing Problem with Time Windows (MS-VRPTW) is established in this paper, with two objectives of minimizing the total driver payment and the total travel distance. Due to the large scale and nonlinear constraints, the exact search showed is not suitable to MS-VRPTW. An initial solution construction heuristic (EBIH) and a selective perturbation Hyper-Heuristic (GIHH) are thus developed. In GIHH, five heuristics with different extents of perturbation at the low level are adaptively selected by a high level selection scheme with the Hill Climbing acceptance criterion. Two guidance indicators are devised at the high level to adaptively adjust the selection of the low level heuristics for this bi-objective problem. The two indicators estimate the objective value improvement and the improvement direction over the Pareto Front, respectively. To evaluate the generality of the proposed algorithms, a set of benchmark instances with various features is extracted from real-life historical datasets. The experiment results show that GIHH significantly improves the quality of the final Pareto Solution Set, outperforming the state-of-the-art algorithms for similar problems. Its application on VRPTW also obtains promising results.\",\n \"Title: Computing semantic similarity based on novel models of semantic representation using Wikipedia.\\nYear: 2018\\n\\nAbstract: •Two semantic models for the representation of concepts are proposed.•The presented semantic models focus on Wikipedia Category Graph and hyperlinks.•Several methods to semantic similarity computation for concepts are provided.\",\n \"Title: An Investigation on Compound Neighborhoods for VRPTW.\\nYear: 2016\\n\\nAbstract: The Vehicle Routing Problem with Time Windows (VRPTW) consists of constructing least cost routes from a depot to a set of geographically scattered service points and back to the depot, satisfying service time intervals and capacity constraints. A Variable Neighbourhood Search algorithm which can simultaneously optimize both objectives of VRPTW (to minimize the number of vehicles and the total travel distance) is proposed in this paper. The three compound neighbourhood operators are developed with regards to problem characteristics of VRPTW. Compound neighbourhoods combine a number of independent neighbourhood operators to explore a larger scale of neighbourhood search space. Performance of these operators has been investigated and is evaluated on benchmark problems.\",\n \"Title: Fusion of Panchromatic and Multispectral Images via Coupled Sparse Non-Negative Matrix Factorization.\\nYear: 2016\\n\\nAbstract: In this paper, we construct a new coupled sparse non-negative matrix factorization (CSNMF) model for the fusion of panchromatic (PAN) and multispectral (MS) images. Two CSNMFs are developed for a joint sparse representation of MS and PAN images. Moreover, a sequential iterative algorithm is proposed to simultaneously find the solution to CSNMF. Because learned dictionaries can reveal the latent st...\",\n \"Title: Hyper-heuristics: a survey of the state of the art.\\nYear: 2013\\n\\nAbstract: Hyper-heuristics comprise a set of approaches that are motivated (at least in part) by the goal of automating the design of heuristic methods to solve hard computational search problems. An underlying strategic research challenge is to develop more generally applicable search methodologies. The term hyperheuristic is relatively new; it was first used in 2000 to describe heuristics to choose heuristics in the context of combinatorial optimisation. However, the idea of automating the design of heuristics is not new; it can be traced back to the 1960s. The definition of hyper-heuristics has been recently extended to refer to a search method or learning mechanism for selecting or generating heuristics to solve computational search problems. Two main hyper-heuristic categories can be considered: heuristic selection and heuristic generation. The distinguishing feature of hyper-heuristics is that they operate on a search space of heuristics (or heuristic components) rather than directly on the search space of solutions to the underlying problem that is being addressed. This paper presents a critical discussion of the scientific literature on hyper-heuristics including their origin and intellectual roots, a detailed account of the main types of approaches, and an overview of some related areas. Current research trends and directions for future research are also discussed.\",\n \"Title: Multi-objective ant colony optimization algorithm based on decomposition for community detection in complex networks\\nYear: 2019\\n\\nAbstract: Community detection aims to identify topological structures and discover patterns in complex networks, which presents an important problem of great significance. The problem can be modeled as an NP hard combinatorial optimization problem, to which multi-objective optimization has been applied, addressing the common resolution limitation problem in modularity-based optimization. In the literature, ant colony optimization (ACO) algorithm, however, has been only applied to community detection with single objective. This is due to the main difficulties in defining and updating the pheromone matrices, constructing the transition probability model, and tuning the parameters. To address these issues, a multi-objective ACO algorithm based on decomposition (MOACO/D-Net) is proposed in this paper, minimizing negative ratio association and ratio cut simultaneously in community detection. MOACO/D-Net decomposes the community detection multi-objective optimization problem into several subproblems, and each one corresponds to one ant in the ant colony. Furthermore, the ant colony is partitioned into groups, and ants in the same group share a common pheromone matrix with information learned from high-quality solutions. The pheromone matrix of each group is updated based on updated nondominated solutions in this group. New solutions are constructed by the ants in each group using a proposed transition probability model, and each of them is then improved by an improvement operator based on the definition of strong community. After improvement, all the solutions are compared with the solutions in the external archive and the nondominated ones are added to the external archive. Finally each ant updates its current solution based on a better neighbor, which may belong to an adjacent group. The resulting final external archive consists of nondominated solutions, and each one corresponds to a different partition of the network. Systematic experiments on LFR benchmark networks and eight real-world networks demonstrate the effectiveness and robustness of the proposed algorithm. The ranges of proper values for each parameter are also analyzed, addressing the key issue of parameter tuning in ACO algorithms based on a large number of tests conducted.\",\n \"Title: Semantic similarity measures for formal concept analysis using linked data and WordNet\\nYear: 2019\\n\\nAbstract: Formal Concept Analysis (FCA) is a field of applied mathematics with its roots in order theory, in particular the theory of complete lattices. It is not only a method for data analysis and knowledge representation, but also a formal formulation for concept formation and learning. Over the past 20 years, FCA has been widely studied. In this paper, the current research progresses and the existing problems of similarity measures in FCA are analyzed. To address the drawbacks of the existing methods, we propose a kind of novel semantic similarity measure for FCA by using Linked Data and WordNet. We aim to develop a method that is fully automatic without requiring predefined domain ontologies and can be used independently of the domain in applications requiring semantic similarity measures in FCA. To realize the semantic similarity estimation for FCA, we firstly extend the similarity assessment methods for resources (or entities) in Linked Data into semantic cases by using WordNet. Furthermore, we propose two kinds of semantic similarity measures (i.e., context-free method and context-aware method) for FCA concepts and concept lattices, respectively. Compared with the existing similarity measure methods in FCA, the proposed approach uses concept of possibility theory to determine lower and upper bounds of similarity intervals. Finally, we evaluate the proposed similarity assessment approaches by applying them to real-worlds datasets.\",\n \"Title: Automated design of search algorithms: Learning on algorithmic components\\nYear: 2021\\n\\nAbstract: This paper proposes AutoGCOP, a new general framework for automated design of local search algorithms. In a recently established General Combinatorial Optimisation Problem (GCOP) model, the problem of algorithm design itself is defined as a combinatorial optimisation problem. AutoGCOP defines a general framework to optimise the composition of elementary algorithmic components as decision variables in GCOP. By modelling various well-known local search meta-heuristics within a general framework, AutoGCOP supports automatic design of new novel algorithms which may be highly different from those manually designed in the literature.\",\n \"Title: Assessing hyper-heuristic performance\\nYear: 2021\\n\\nAbstract: Limited attention has been paid to assessing the generality performance of hyper-heuristics. The performance of hyper-heuristics has been predominately assessed in terms of optimality which is not ideal as the aim of hyper-heuristics is not to be competitive with state of the art approaches but rather to raise the level of generality, i.e. the ability of a technique to produce good results for different problem instances or problems rather than the best results for some instances and poor results for others. Furthermore from existing literature in this area it is evident that different hyper-heuristics aim to achieve different levels of generality and need to be assessed as such. To cater for this the paper firstly presents a new taxonomy of four different levels of generality that can be attained by a hyper-heuristic based on a survey of the literature. The paper then proposes a performance measure to assess the performance of different types of hyper-heuristics at the four levels of generality in terms of generality rather than optimality. Three case studies from the literature are used to demonstrate the application of the generality performance measure. The paper concludes by examining how the generality measure can be combined with measures of other performance criteria, such as optimality, to assess hyper-heuristic performance on more than one criterion.\",\n \"Title: An ACO for energy-efficient and traffic-aware virtual machine placement in cloud computing\\nYear: 2022\\n\\nAbstract: This paper formulates a virtual machine placement (VMP) problem, where the total power consumption of physical machines (PMs) and switches and the total network bandwidth resource consumption among VMs are jointly minimized. To address the problem, we present an energy- and traffic-aware ant colony optimization (ETA-ACO) algorithm. Three novel schemes are introduced to enhance the performance of ETA-ACO, including an energy- and bandwidth-aware PM selection scheme, a traffic-based VM ordering scheme, and a direct information exchange scheme. The first scheme consists of two steps when selecting a PM to host a given VM. In the first step, PMs with lower power consumption are preserved. In the second step, the one with the lowest bandwidth resource consumption is chosen to host the VM. In the second scheme, ETA-ACO places VMs in descending order by their traffic demands. The third scheme constructs new solutions by spreading the components of the best solution over a group of constructed solutions. Simulation results demonstrate that the three novel schemes are effective in adapting ETA-ACO for the VMP problem. Besides, ETA-ACO outperforms a number of state-of-the-art heuristics and metaheuristics in terms of solution quality.\",\n \"Title: Adaptive Fuzzy Learning Superpixel Representation for PolSAR Image Classification\\nYear: 2022\\n\\nAbstract: The increasing applications of polarimetric synthetic aperture radar (PolSAR) image classification demand for effective superpixels' algorithms. Fuzzy superpixels' algorithms reduce the misclassification rate by dividing pixels into superpixels, which are groups of pixels of homogenous appearance and undetermined pixels. However, two key issues remain to be addressed in designing a fuzzy superpixel algorithm for PolSAR image classification. First, the polarimetric scattering information, which is unique in PolSAR images, is not effectively used. Such information can be utilized to generate superpixels more suitable for PolSAR images. Second, the ratio of undetermined pixels is fixed for each image in the existing techniques, ignoring the fact that the difficulty of classifying different objects varies in an image. To address these two issues, we propose a polarimetric scattering information-based adaptive fuzzy superpixel (AFS) algorithm for PolSAR images classification. In AFS, the correlation between pixels' polarimetric scattering information, for the first time, is considered through fuzzy rough set theory to generate superpixels. This correlation is further used to dynamically and adaptively update the ratio of undetermined pixels. AFS is evaluated extensively against different evaluation metrics and compared with the state-of-the-art superpixels' algorithms on three PolSAR images. The experimental results demonstrate the superiority of AFS on PolSAR image classification problems.\",\n \"Title: Case-based reasoning system for fault diagnosis of aero-engines\\nYear: 2022\\n\\nAbstract: •A highly accurate CBR system with novel similarity measure for fault diagnosis.•Integrating three local similarity measures associated with different attributes.•A tree-based semantic similarity measure linking fault part and fault mode.•The first tentative case base in the field of aero-engine fault diagnosis.\",\n \"Title: A deep reinforcement learning based hyper-heuristic for combinatorial optimisation with uncertainties\\nYear: 2022\\n\\nAbstract: •A hyper-heuristic framework is proposed for online combinatorial optimisation.•A deep reinforcement learning agent is first used in hyper-heuristic.•The method holds better convergence performance than the existing methods.•Our approach improves the interpretability of traditional DRL.\",\n \"Title: Identify Patterns in Online Bin Packing Problem: An Adaptive Pattern-Based Algorithm\\nYear: 2022\\n\\nAbstract: Bin packing is a typical optimization problem with many real-world application scenarios. In the online bin packing problem, a sequence of items is revealed one at a time, and each item must be packed into a bin immediately after its arrival. Inspired by duality in optimization, we proposed pattern-based adaptive heuristics for the online bin packing problem. The idea is to predict the distribution of items based on packed items, and to apply this information in packing future arrival items in order to handle uncertainty in online bin packing. A pattern in bin packing is a combination of items that can be packed into a single bin. Patterns selected according to past items are adopted and periodically updated in scheduling future items in the algorithm. Symmetry in patterns and the stability of patterns in the online bin packing problem are discussed. We have implemented the algorithm and compared it with the Best-Fit in a series of experiments with various distribution of items to show its effectiveness.\",\n \"Title: An Improved Ant Colony Approach for the Competitive Traveling Salesmen Problem\\nYear: 2022\\n\\nAbstract: A competitive traveling salesmen problem is a variant of traveling salesman problem in that multiple agents compete with each other in visiting a number of cities. The agent who is the first one to visit a city will receive a reward. Each agent aims to collect as more rewards as possible with the minimum traveling distance. There is still not effective algorithms for this complicated decision making problem. We investigate an improved ant colony approach for the competitive traveling sales-men problem which adopts a time dominance mechanism and a revised pheromone depositing method to improve the quality of solutions with less computational complexity. Simulation results show that the proposed algorithm outperforms the state of art algorithms.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":95,"string":"95"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13345,"string":"13,345"}}},{"rowIdx":13346,"cells":{"question_id":{"kind":"string","value":"Vincenzo Lippiello"},"question":{"kind":"string","value":"Generate an abstract for the title \"3D monocular robotic ball catching\" using the following items: Robot, Catching, Visual system, Estimation algorithm, Industrial robotic system."},"answer":{"kind":"string","value":"A new method to catch a thrown ball with a robot endowed with an eye-in-hand monocular visual system integrated into a gripper is proposed. As soon as the thrown ball is recognized by the visual system, the camera carried by the robot end-effector is forced to follow a baseline in the space so as to acquire an initial dataset of visual measurements from several points of view, providing a first estimate of the catching point through a linear estimation algorithm. Hereafter, additional measurements are acquired to constantly refine the previous estimate by exploiting a nonlinear estimation algorithm. During the robot trajectory, the translational components of the camera are controlled in such a way as to follow the planned path to intercept the ball, while the rotational components are forced to keep the ball into the field of view. Experimental results performed on a common industrial robotic system prove the effectiveness of the presented solution."},"correct_answer":{"kind":"string","value":"A new method to catch a thrown ball with a robot endowed with an eye-in-hand monocular visual system integrated into a gripper is proposed. As soon as the thrown ball is recognized by the visual system, the camera carried by the robot end-effector is forced to follow a baseline in the space so as to acquire an initial dataset of visual measurements from several points of view, providing a first estimate of the catching point through a linear estimation algorithm. Hereafter, additional measurements are acquired to constantly refine the previous estimate by exploiting a nonlinear estimation algorithm. During the robot trajectory, the translational components of the camera are controlled in such a way as to follow the planned path to intercept the ball, while the rotational components are forced to keep the ball into the field of view. Experimental results performed on a common industrial robotic system prove the effectiveness of the presented solution."},"documents":{"kind":"list like","value":["Title: Managing redundant visual measurements for accurate pose tracking\nYear: 2003\n\nAbstract: This paper proposes an algorithm for managing redundant measurements provided by a stereo multi-camera system to achieve accurate visual tracking of a moving object. Self-occlusion, different visual resolution zones and optimal selection of redundant measurements are some of the problems addressed. The algorithm uses the extended Kalman filter embedded in a computational efficient pose estimation procedure based on Binary Space Partitioning Tree geometric modelling of 3D objects. Experimental results are presented for the case of an object moving in the visual space of two fixed cameras.","Title: An Open Architecture For Sensory Feedback Control Of A Dual-Arm Industrial Robotic Cell\nYear: 2007\n\nAbstract: Purpose - To present an open architecture for real-time sensory feedback control of a dual-arm industrial robotic cell. The setup is composed of two industrial robot manipulators equipped with force/torque sensors and pneumatic grippers, a vision system and a belt conveyor,Design/methodology/approach - The original industrial robot controllers have been replaced by a single PC with software running under a real-time variant of the Linux operative system.Findings - The new control architecture allows advanced control schemes to be developed and tested for the single robots and for the dual-arm robotic cell, including force control and visual servoing tasks.Originality/value - An advanced user interface and a simulation environment have been developed, which permit fast, safe and reliable prototyping of planning and control algorithms.","Title: Floating Visual Grasp of Unknown Objects Using an Elastic Reconstruction Surface\nYear: 2009\n\nAbstract: In this paper a new method for fast visual grasp of unknown objects is presented. The method is composed of an object surface reconstruction algorithm and of a local grasp planner, evolving in a parallel way. The reconstruction algorithm makes use of images taken by a camera carried by the robot, mounted in an eye-in-hand configuration. An elastic reconstruction sphere, composed by masses interconnected each other by springs, is virtually placed around the object. The sphere is let to evolve dynamically under the action of external forces, which push the masses towards the object centroid. To smoothen the surface evolution, spatial dampers are attached to each mass. The reconstruction surface shrinks toward its center of mass until some pieces of its surface intercept the object visual hull, and thus local rejection forces are generated to push out the reconstruction points until they stay into the visual hull. This process shapes the sphere around the unknown object. Running in parallel to the reconstruction algorithm, the grasp planner moves the fingertips, floating on the current available reconstructed surface, according to suitable quality measures. The fingers keep moving towards local minima depending on the evolution of the reconstruction surface deformation. The process stops when the object has been completely reconstructed and the planner reaches a local minimum. Quality measures considering both hand and grasp proprieties are adopted. Simulations are presented, showing the effectiveness of the proposed algorithm.","Title: A Position-Based Visual Impedance Control for Robot Manipulators\nYear: 2007\n\nAbstract: In this paper, an approach to interaction control of a robot manipulator with a partially known environment is proposed. The environment is a rigid object of known geometry but of unknown and possibly time-varying position and orientation. An algorithm for online estimation of the object pose is adopted, based on visual data provided by a camera as well as on forces and moments measured during the interaction with the environment. This algorithm is embedded into an impedance control scheme, resulting in a position-based visual impedance control. Experimental results are presented for the case of an industrial robot manipulator in contact with a planar surface.","Title: Visual tracking of multiple objects using binary space partitioning trees\nYear: 2003\n\nAbstract: The use of visual sensors may have high impact in robotic applications where it is required to measure the pose (position and orientation) and the visual features of objects moving in unstructured environments. In this paper, the problem of real-time estimation of the position and orientation of of multiple objects is considered. Special emphasis is devoted to the case when two or more objects overlap with respect to the visual system causing occlusion. The algorithm is based on the Kalman filtering and Binary Space Partition (BSP) tree representations of the objects geometry. The real-time implementation of the algorithm is experimentally tested for the case of visual tracking of two objects using two cameras.","Title: An Occlusion Prediction Algorithm For Visual Servoing Tasks In A Multi-Amt Robotic Cell\nYear: 2005\n\nAbstract: This paper presents a new approach to the prediction of visual occlusions for a robotic system performing visual servoing tasks. The case of a multi-arm robotic cell equipped with a multi-camera eye-to-hand visual system is considered. The proposed approach is able to predict the self occlusions as well as the mutual occlusions caused by the robot links and tools. The algorithm is based on the geometric representation of the cell in terms of a BSP tree, assuming that the CAD geometry of the objects and the kinematic model of the multi-arm robotic system are known. Experimental results are presented for the case of two industrial robots performing a vision-guided grasping task.","Title: A grasping force optimization algorithm for dexterous robotic hands.\nYear: 2012\n\nAbstract: The problem of grasping force optimization for a robotic system equipped with multi-fingered hands is considered in this paper. This problem is cast as a convex optimization problem, considering also joint torque constraints. A solution suitable for on-line implementation is proposed, which allows a substantial reduction of the computational load by dynamically decreasing the number of active torque constraints. Moreover, for the case of a bimanual manipulation system, a sub-optimal single-hand optimization algorithm is presented and compared with the optimal one. The effectiveness of the described methods has been tested in a simulation case study.","Title: Mav Indoor Navigation Based On A Closed-Form Solution For Absolute Scale Velocity Estimation Using Optical Flow And Inertial Data\nYear: 2011\n\nAbstract: A new vision-based obstacle avoidance technique for indoor navigation of Micro Aerial Vehicles (MAVs) is presented in this paper. The vehicle trajectory is modified according to the obstacles detected through the Depth Map of the surrounding environment, which is computed online using the Optical Flow provided by a single onboard omnidirectional camera. An existing closed-form solution for the absolute-scale velocity estimation based on visual correspondences and inertial measurements is generalized and here employed for the Depth Map estimation. Moreover, a dynamic region-of-interest for image features extraction and a self-limitation control for the navigation velocity are proposed to improve safety in view of the estimated vehicle velocity. The proposed solutions are validated by means of simulations.","Title: Robust Visual Tracking Using A Fixed Multi-Camera System\nYear: 2003\n\nAbstract: The problem of tracking the position and orientation of a moving object using a stereo camera system is considered in this paper. A robust algorithm based on the extended Kalman filter is adopted, combined with an efficient selection technique of the object image features, based on Binary Space Partitioning tree geometric models. An experimental study is carried out using a vision system of two fixed cameras.","Title: Multi-fingered grasp synthesis based on the object dynamic properties.\nYear: 2013\n\nAbstract: The grasping and manipulation of objects, especially when they are heavy with respect to the hand power capability, requires the synthesis of grasp configurations that explicitly take into account the dynamic properties of the object. Specifically, suitable grasp configurations reducing gravitational and inertial effects during object manipulation, and minimizing and equally distributing the grasping forces among all the available fingers, must be computed. A new method for fast synthesis of multi-fingered grasp configurations is proposed in this paper. In particular, to reduce the computational complexity, all the regions of the object surface favoring the synthesis of minimal inertia grasps are evaluated first. Then, a reduced number of discrete grasping regions are selected on the basis of the fingertip size, model uncertainty, and surface curvature. Finally, an exhaustive search of the optimal grasp configurations with respect to the grasp quality is performed. Several case studies and comparisons with other methods are proposed to demonstrate the effectiveness of the proposed approach.","Title: Surface model reconstruction of 3D objects from multiple views\nYear: 2009\n\nAbstract: A points surface reconstruction algorithm of 3D object models from multiple silhouettes is proposed in this paper. Some images of the target object are taken from a circular trajectory by a robot with a camera mounted in an eye-in-hand configuration. The silhouettes of the observed object are evaluated for each view using a blob analysis process, and from those a set of points that sample a reconstruction sphere surrounding the target object are estimated. The sphere sample points are attracted by the object center of mass using a variable step according to the distance from the silhouettes contours. For each point, the iterative process of constriction is stopped when all the back-projections of the point are within the corresponding silhouettes. Moreover, a new method based on a rough estimation of object dimension is proposed to reduce the disturbances due to projection and shadow cones. Simulations and experiments are presented to evaluate the performance of the proposed algorithm.","Title: Floating visual grasp of unknown objects\nYear: 2009\n\nAbstract: A new method for fast visual grasp of unknown objects using a camera mounted on a robot in an eye-in-hand configuration is presented. The method is composed of a fast iterative object surface reconstruction algorithm and of a local grasp planner, evolving in a synchronized parallel way. The reconstruction algorithm makes use of images taken by a camera carried by the robot. A reconstruction sphere, virtually placed around the object, is iteratively compressed towards the object visual hull, dragging out the fingers attached to it. Between two steps of the reconstruction process, the planner moves the fingers, floating on the current reconstructed surface, according to suitable quality measures. The fingers keep moving until a local minimum is achieved, then a new object surface estimation provided by the reconstruction process is considered. Quality measures considering both hand and grasp proprieties are adopted. Simulations are presented to show the performance of the proposed algorithm.","Title: Airobots: Innovative Aerial Service Robots For Remote Inspection By Contact\nYear: 2013\n\nAbstract: This video presents experiments conducted within the final review meeting demonstration session of the AIRobots project. AIRobots started at 2010 and the final review meeting took place on 22 of March, 2013. The presented experiments cover a wide area of the challenges related with aerial industrial inspection. In particular, multiple test- cases related with both vision- based and contact- based inspection and in general physical interaction are shown. It is highlighted that these experiments were recorded live during the project demonstration and evaluation process.","Title: Grasp planning and parallel control of a redundant dual-arm/hand manipulation system.\nYear: 2013\n\nAbstract: In this paper, a kinematic model of a dual-arm/hand robotic system is derived, which allows the computation of the object position and orientation from the joint variables of each arm and each finger as well as from a suitable set of contact variables. On the basis of this model, a motion planner is designed, where the kinematic redundancy of the system is exploited to satisfy some secondary tasks aimed at ensuring grasp stability and manipulation dexterity without violating physical constraints. To this purpose, a prioritized task sequencing with smooth transitions between tasks is adopted. Afterwards, a controller is designed so as to execute the motion references provided by the planner and, at the same time, achieve a desired contact force exerted by each finger on the grasped object. To this end, a parallel position/force control is considered. A simulation case study has been developed by using the dynamic simulator GRASPIT!, which has been suitably adapted and redistributed.","Title: A Framework for Force and Visual Control of Robot Manipulators\nYear: 2007\n\nAbstract: A framework for force and visual control of robot manipulators in contact with a partially known environment is proposed. The environment is modelled as a rigid object of known geometry but of unknown and time-varying pose. An algorithm or online estimation of the object pose is adopted; based on visual data as well as on force measurements. This information is used by a force/position controller. The resulting control scheme has a inner/outer structure where the outer loop performs pose estimation and the inner loop is devoted to interaction control.","Title: Aerial service vehicles for industrial inspection: task decomposition and plan execution\nYear: 2013\n\nAbstract: This work proposes a high-level control system designed for an Aerial Service Vehicle capable of performing complex tasks in close and physical interaction with the environment in an autonomous manner. We designed a hybrid control architecture which integrates task, path, motion planning/replanning, and execution monitoring. The high-level system relies on a continuous monitoring and planning cycle to suitably react to events, user interventions, and failures, communicating with the low level control layers. The system has been assessed on real-world and simulated scenarios representing an industrial environment.","Title: Real-time visual tracking based on BSP-tree representations of object boundary\nYear: 2005\n\nAbstract: In this paper an algorithm for real-time estimation of the position and orientation of a moving object using a video camera is presented. The algorithm is based on the extended Kalman filter which iteratively computes the object pose from the position measured in the image plane of a set of feature points of the object. A new technique is proposed for the selection of the optimal feature points based on the representation of the object geometry by means of a Binary Space Partitioning (BSP) tree. At each sample time, a visit algorithm of the tree allows pre-selecting all the feature points of the object that are visible from the camera in the pose predicted by the Kalman filter. A further selection is performed to find the optimal set of visible points to be used for image feature extraction. Experimental results are presented which confirm the feasibility and effectiveness of the proposed technique.","Title: Robot Interaction Control Using Force And Vision\nYear: 2006\n\nAbstract: The problem of interaction control of a robot manipulator with a partially known environment is considered. The environment is a rigid object of known geometry but of unknown and possibly time varying position and orientation. An algorithm for online estimation of the object pose is presented, based on visual data provided by a camera. The estimation accuracy is improved during the interaction by using also force and joint position measurements. The proposed method can be exploited to implement any kind of interaction control strategy. A simulation case study is considered for the case of impedance control of a robot manipulator in contact with a planar surface.","Title: Visual And Inertial Multi-Rate Data Fusion For Motion Estimation Via Pareto-Optimization\nYear: 2013\n\nAbstract: Motion estimation is an open research field in control and robotic applications. Sensor fusion algorithms are generally used to achieve an accurate estimation of the vehicle motion by combining heterogeneous sensors measurements with different statistical characteristics. In this paper, a new method that combines measurements provided by an inertial sensor and a vision system is presented. Compared to classical model-based techniques, the method relies on a Pareto optimization that trades off the statistical properties of the measurements. The proposed technique is evaluated with simulations in terms of computational requirements and estimation accuracy with respect to a classical Kalman filter approach. It is shown that the proposed method gives an improved estimation accuracy at the cost of a slightly increased computational complexity.","Title: Robotic Ball Catching with an Eye-in-Hand Single-Camera System\nYear: 2015\n\nAbstract: In this paper, a unified control framework is proposed to realize a robotic ball catching task with only a moving single-camera (eye-in-hand) system able to catch flying, rolling, and bouncing balls in the same formalism. The thrown ball is visually tracked through a circle detection algorithm. Once the ball is recognized, the camera is forced to follow a baseline in the space so as to acquire an initial dataset of visual measurements. A first estimate of the catching point is initially provided through a linear algorithm. Then, additional visual measurements are acquired to constantly refine the current estimate by exploiting a nonlinear optimization algorithm and a more accurate ballistic model. A classic partitioned visual servoing approach is employed to control the translational and rotational components of the camera differently. Experimental results performed on an industrial robotic system prove the effectiveness of the presented solution. A motion-capture system is employed to validate the proposed estimation process via ground truth.","Title: Robot Vision: Obstacle-Avoidance Techniques for Unmanned Aerial Vehicles.\nYear: 2013\n\nAbstract: In this article, a vision-based technique for obstacle avoidance and target identification is combined with haptic feedback to develop a new teleoperated navigation system for underactuated aerial vehicles in unknown environments. A three-dimensional (3-D) map of the surrounding environment is built by matching the keypoints among several images, which are acquired by an onboard camera and stored in a buffer together with the corresponding estimated odometry. Hence, based on the 3-D map, a visual identification algorithm is employed to localize both obstacles and the desired target to build a virtual field accordingly. A bilateral control system has been developed such that an operator can safely navigate in an unknown environment and perceive it by means of a vision-based haptic force-feedback device. Experimental tests in an indoor environment verify the effectiveness of the proposed teleoperated control.","Title: Monocular Eye-In-Hand Robotic Ball Catching with Parabolic Motion Estimation.\nYear: 2012\n\nAbstract: A monocular robotic ball catching system is presented in this paper. A visual servoing control is used in order to keep a thrown ball in the field of view of an eye-in-hand camera and generate a robot motion toward the ball interception point. Simultaneously, the 3D ball trajectory is estimated with a least-squares method, which employs only information provided by the available camera. Experiments demonstrate the feasibility of the proposed approach.","Title: Task priority control for aerial manipulation\nYear: 2014\n\nAbstract: This paper presents a task oriented control strategy for aerial vehicles equipped with a manipulator. A camera is attached to the end-effector of the manipulator to perform a primary task consisting on visual servoing towards a desired target. Over-actuation of the whole quadrotor-arm system is exploited to achieve secondary velocity tasks. One subtask is proposed to horizontally stabilize the platform during flight by aligning the arm center of gravity with the quadrotor gravitational vector. The arm singularities and manipulability are addressed by another subtask that leads the arm to a preferable configuration, and also takes into account the arm joint limits. The performance of the whole visual servo and secondary tasks control scheme is shown in a Robot Operating System (ROS) implementation.","Title: Image moments-based velocity estimation of UAVs in GPS denied environments\nYear: 2014\n\nAbstract: This paper proposes a new method for quadrotor translational velocity estimation using only onboard sensing and without any prior knowledge on the geometry of the scene. Image moments extracted from the onboard camera images, together with onboard IMU data, are exploited in an Unscented Kalman filter (UKF). Differently with respect to the literature approaches, the proposed method is independent from the scale factor when considering a planar visual object. The estimation algorithm, in addition of involving matrices of constant size, does not require a well-textured environment, but can rather operate with few visual features. This makes it computationally-cheap, thus appealing for onboard applications. Experiments on a flying real quadrotor are carried out in a GPS-denied and poorly-textured environment in order to verify the validity of the proposed approach as well as its robustness to measurement noises and errors.","Title: Emergency landing for a quadrotor in case of a propeller failure: A backstepping approach\nYear: 2014\n\nAbstract: A backstepping approach is proposed in this paper to cope with the failure of a quadrotor propeller. The presented methodology supposes to turn off also the motor which is opposite to the broken one. In this way, a birotor configuration with fixed propellers is achieved. The birotor is controlled to follow a planned emergency landing trajectory. Theory shows that the birotor can reach any point in the Cartesian space losing the possibility to control the yaw angle. Simulation tests are employed to validate the proposed controller design.","Title: Emergency landing for a quadrotor in case of a propeller failure: A PID based approach\nYear: 2014\n\nAbstract: A controller dealing with the failure of a quadrotor's motor is presented in this paper. Supposing that the failure has been already detected by the system, the quadrotor is modelled as a birotor with fixed propellers and it is controlled to follow a planned emergency landing trajectory. Theory shows that, in such a configuration, the aerial vehicle is allowed to reach any position in the Cartesian space dropping the possibility to control the yaw angle. Simulations are presented to confirm the presented methodology.","Title: Image-based control for dynamically cross-coupled aerial manipulation\nYear: 2014\n\nAbstract: Manipulation tasks carried out with aerial platforms composed of a UAV and a robotic arm involve cross-coupled dynamics between these subsystems. This paper proposes a new controller for this class of aerial robotic systems that allows regulating on velocity commands generated by an outer image-based visual-servo scheme. The controller, that considers the full dynamics of the system, is designed based on the integral backstepping approach. Visual feedback provided by an onboard camera is employed into a new visual servo scheme to simultaneously generate velocity commands for the UAV and the manipulator so that a visual target is reached. The control system takes into account the under-actuation related to rotary-wing vehicles, while at the same time it exploits the functionality system redundancy to achieve the task. Simulation results validate the proposed control system, as well as its robustness to large modeling error and measurement noise.","Title: Impedance control of VToL UAVs with a momentum-based external generalized forces estimator\nYear: 2014\n\nAbstract: An estimator of external generalized forces (force plus moments) acting on aerial platforms, and based on the momentum of the mechanical system, is proposed for the control of VToL UAVs together with a hierarchical architecture separating the translational and rotational dynamics of the vehicle. The closed-loop system equations are shaped as mechanical impedances, programmable through the controller gains, and forced by the residuals given by the estimation error. This arrangement allows the VToL UAVs to perform hovering and tracking tasks without a precise knowledge of the vehicle dynamics and in presence of external disturbances and unmodeled aerodynamic effects. Experiments are presented to evaluate the performance of the proposed control design.","Title: Objects motion estimation via BSP tree modeling and Kalman filtering of stereo images\nYear: 2002\n\nAbstract: In this paper a computationally efficient algorithm for real time estimation of the position and orientation of moving objects from visual measurements of a system of fixed cameras is proposed. The algorithm is based on extended Kalman filtering of the measurements of the position of suitable feature points selected on the target objects. The effectiveness of the algorithm is improved by using a pre-selection method of the feature points which takes advantage of the Kalman filter prediction capability combined with a BSP tree modeling technique of the objects geometry. Computer simulations are presented to test the performance of the estimation process in the presence of noise, different types of lens geometric distortion, quantization and calibration errors","Title: A new method of image features pre-selection for real-time pose estimation based on Kalman filter\nYear: 2002\n\nAbstract: The problem of real-time pose estimation of moving objects using a stereo video camera system is considered in this paper. A computationally efficient algorithm is proposed based on Kalman filtering of the position measurements of suitable feature points selected on the target objects. The efficiency of the algorithm is improved by adopting a new pre-selection technique of the feature points, based on binary space partition (BSP) trees, which takes advantage of the Kalman filter prediction capability. Computer simulations are presented.","Title: Coping with occlusions in visual tracking of multiple objects\nYear: 2003\n\nAbstract: The problem of visual tracking of multiple objects is considered in this paper. Special emphasis is devoted to the case when two or more objects overlap with respect to the visual system causing occlusion. The algorithm is based on the Kalman filtering and binary space partition tree representations of the objects geometry. The real-time implementation of the algorithm is experimentally tested for the case of visual tracking of two objects using two cameras.","Title: Visual motion estimation of 3D objects: an adaptive extended Kalman filter approach\nYear: 2004\n\nAbstract: An algorithm for the visual estimation of the pose of a moving object is presented in this paper. The algorithm exploits the prediction capability of the extended Kalman Filter to realize in real time a dynamic optimal selection of the object image features used for pose estimation. The robustness of the system with respect to the measurement noise and modelling errors is enhanced by using an adaptive scheme. Experimental case studies are presented to prove the effectiveness of the proposed approach.","Title: RePLiCS: an environment for open real-time control of a dual-arm industrial robotic cell based on RTAI-Linux\nYear: 2005\n\nAbstract: An environment for open real-time control of an industrial robotic cell is presented in this paper. The experimental setup is composed of two industrial robot manipulators equipped with force/torque sensors and pneumatic grippers, a vision system and a belt conveyor. The original industrial robot controllers have been replaced by a single PC with software running under a real-time variant of the Linux operative system. The new control environment allows advanced control schemes to be developed and tested for the single robots and for the dual-arm robotic cell, including force control and visual servoing tasks. An advanced user interface and a simulation environment have been developed, which permit fast, safe and reliable prototyping of planning and control algorithms.","Title: 3D pose estimation for robotic applications based on a multi-camera hybrid visual system\nYear: 2006\n\nAbstract: An algorithm for the estimation of the position and orientation of a moving object using a hybrid eye-in-hand/eye-to-hand multi-camera system is presented. Based on the extended Kalman filter, this approach exploits the data provided by all the cameras without \"a priori\" discrimination, allowing real-time estimation. The proposed formulation can be used with different kinds of image features and different representations of the object orientation. A simulation case study is reported to test the feasibility and the effectiveness of the proposed technique","Title: 3D monocular robotic ball catching with an iterative trajectory estimation refinement\nYear: 2012\n\nAbstract: In this paper, a 3D robotic ball catching algorithm which employs only an eye-in-hand monocular visual-system is presented. A partitioned visual servoing control is used in order to generate the robot motion, keeping always the ball in the field of view of the camera. When the ball is detected, the camera mounted on the robot end-effector is commanded to follow a suitable baseline in order to acquire measurements and provide a first possible interception point through a linear estimation process. Thereafter, further visual measures are acquired in order to continuously refine the previous prediction through a non-linear estimation process. Experimental results show the effectiveness of the proposed solution.","Title: A Grasping Force Optimization Algorithm for Multiarm Robots With Multifingered Hands\nYear: 2013\n\nAbstract: The computation of the grasping forces for a multiarm robotic manipulation system (e.g., an anthropomorphic bimanual system) is considered in this paper. This problem is formulated as a convex optimization problem, also considering joint torque constraints. An algorithmic solution suitable for online implementation is presented, which allows a substantial reduction in the computational load by adopting a compact formulation and dynamically decreasing the number of active torque constrains. Moreover, for the case of a bimanual manipulation system, a suboptimal single-hand optimization algorithm is proposed and compared with that providing the optimal solution. Finally, a new algorithm for a valid initial-point evaluation is proposed. The effectiveness of the described methods has been tested in a simulation case study where the grasping forces of a humanoid torso equipped with two five-finger robotic hands are modified online to handle a load with a time-varying mass.","Title: Preshaped visual grasp of unknown objects with a multi-fingered hand\nYear: 2010\n\nAbstract: In this paper a method for fast visual grasp of unknown objects with a multi-fingered hand is presented. The algorithm is composed of an object surface reconstruction algorithm and a local grasp planner, evolving in parallel. The former uses an elastic reconstruction surface, whose dimensions are assigned initially by a preshaping process, and which shrinks toward the object until some parts of the surface intercept the object visual hull. The latter moves the fingertips on the current available reconstruction surface towards points which are optimal (in a local sense) with respect to a certain number of indices weighting both the grasp quality and the kinematic configuration of the hand. Experiments are presented, showing the effectiveness of the proposed algorithm.","Title: Visual coordinated landing of a UAV on a mobile robot manipulator\nYear: 2013\n\nAbstract: In this paper an image-based visual-servoing control law for the coordinated landing of a VToL UAV on an actuated landing platform is proposed. The landing platform is carried by a mobile manipulator composed of a mobile platform and a robotic arm. The UAV is endowed with a downward camera employed for the coordination of the landing manoeuvres. The presence of redundancy in the system at the task level, the intrinsic redundancy of the mobile manipulator, and the under-actuation of the UAV are explicitly addressed into the proposed control law. The effectiveness of the proposed approach is tested though simulations.","Title: Online dextrous-hand grasping force optimization with dynamic torque constraints selection\nYear: 2011\n\nAbstract: In this paper, a new algorithm for online grasping force optimization (GFO) of a dextrous robotic hand is presented. The GFO problem is cast in a convex optimization problem, considering also torque joint constraints. The proposed formulation allows to simplify the computational complexity of the problem by dynamically reducing the number of active torque constraints. Moreover, differently from other approaches, it does not require the evaluation of a new initial point at the beginning of each iteration. The effectiveness and the performance of the proposed method have been tested in a simulation case study where the hand manipulates a load with time-varying mass.","Title: A mixed-initiative control system for an Aerial Service Vehicle supported by force feedback\nYear: 2014\n\nAbstract: We present an approach to mixed initiative control for unmanned aerial vehicles (UAVs) where sliding autonomy is supported by mixed-initiative planning and haptic feedback. In the proposed framework, we assume that an autonomous system can plan and execute robotic tasks while a human operator can provide interventions when necessary receiving a force feedback. The haptic feedback is associated with the sensation about how the system is diverging from the planned operations. We tested the system at work in virtual and real environments considering simple navigation tasks. We compared the performance of human operators with or without the assistance of the force feedback. The collected results support the hypothesis that the proposed approach enables effective and intuitive mixed-initiative control.","Title: Grasp the Possibilities: Anthropomorphic Grasp Synthesis Based on the Object Dynamic Properties\nYear: 2015\n\nAbstract: The synthesis of optimal grasp configurations of heavy objects with anthropomorphic hands benefits from the explicit consideration of the object's dynamic properties. A new solution for the fast synthesis of anthropomorphic grasps that ensures the reduction of gravitational and inertial effects during the execution of manipulation tasks, as well as an equal distribution of the grasping forces among all fingers, is proposed in this article. The reduction of the computational complexity is achieved by considering only the regions of the object surface favoring the synthesis of minimal inertia grasps. Moreover, the hand and fingertip size, the hand kinematics, the object model uncertainty, and the surface curvature are all employed to further reduce the number of discrete grasping regions selected for the computation of the optimal grasp configurations with respect to a number of grasp quality indices. The effectiveness of the proposed method has been demonstrated with several case studies.","Title: Exploiting redundancy in Cartesian impedance control of UAVs equipped with a robotic arm\nYear: 2012\n\nAbstract: A Cartesian impedance control for UAVs equipped with a robotic arm is presented in this paper. A dynamic relationship between generalized external forces acting on the structure and the system motion, which is specified in terms of Cartesian space coordinates, is provided. Through a suitable choice of such variables and with respect to a given task, thanks to the added degrees of freedom given by the robot arm attached to the UAV, it is possible to exploit the redundancy of the system so as to perform some useful subtasks. The hovering control of a quadrotor, equipped with a 3-DOF robotic arm and subject to contact forces and external disturbances acting on some points of the whole structure, is tested in a simulated case study.","Title: Wall inspection control of a VTOL unmanned aerial vehicle based on a stereo optical flow\nYear: 2012\n\nAbstract: An autonomous wall inspection control based on a stereo optical flow, suitable for unmanned aerial vehicles endowed with a stereo vision system, is proposed in this paper. The inspection task consists of simultaneously controlling the inspection velocity along the surface, the relative yaw angle between the vehicle and the observed plane, as well as the orthogonal distance. A virtual spherical camera is considered at the center of gravity of the vehicle. Then, a stereo optical flow, as if it had been acquired by the virtual camera, is generated from the visual data provided by the stereo vision system. The 3D visual measurements are also employed to estimate the relative position and orientation of the observed plane. Hence, the absolute vehicle velocity is estimated by using a robust translational average optical flow by integrating the total stereo flow. Finally, an inspection control and a hovering control are proposed. The effectiveness of the described approach has been demonstrated with a dynamic simulation in an environment composed of two adjacent walls.","Title: Fast incremental clustering and representation of a 3D point cloud sequence with planar regions\nYear: 2012\n\nAbstract: An incremental clustering technique to partition 3D point clouds into planar regions is presented in this paper. The algorithm works in real-time on unknown and noisy data, without any initial assumption. An iterative cluster growing technique is proposed in order to correctly classify a flow of 3D points and to merge close regions. The computational efficiency of the approach is achieved by using an Incremental Principal Component Analysis (IPCA) technique, and with the adoption of a compact geometrical representation based on the concave-hull computation of each cluster. This solution adds a more realistic representation of the observed environment and reduces the number of points needed to identify the cluster shape. The effectiveness of the proposed algorithm has been validated with both synthetic and real data sets.","Title: Nonlinear Visual Control of Unmanned Aerial Vehicles in GPS-Denied Environments\nYear: 2015\n\nAbstract: In this paper, we propose a nonlinear controller that stabilizes unmanned aerial vehicles in GPS-denied environments with respect to visual targets by using only onboard sensing. The translational velocity of the vehicle is estimated online with a nonlinear observer, which exploits spherical visual features as the main source of information. With the proposed solution, only four visual features have shown to be enough for the observer to operate in a real scenario. In addition, the observer is computationally light with constant numerical complexity, involving small-dimension matrices. The observer output is then exploited in a nonlinear controller designed with an integral backstepping approach, thus yielding a novel robust control system. By means of Lyapunov analysis, the stability of the closed-loop system is proved. Extensive simulation and experimental tests with a quadrotor are carried out to verify the validity and robustness of the proposed approach. The control system runs fully onboard on a standard processor, and only a low-cost sensing suite is employed. Tracking of a target whose speed exceeds 2 $mathrm{m/s}$ is also considered in the real-hardware experiments.","Title: Aerial Manipulation: A Literature Review.\nYear: 2018\n\nAbstract: Aerial manipulation aims at combining the versatility and the agility of some aerial platforms with the manipulation capabilities of robotic arms. This letter tries to collect the results reached by the research community so far within the field of aerial manipulation, especially from the technological and control point of view. A brief literature review of general aerial robotics and space manipu...","Title: Passivity-based control of VToL UAVs with a momentum-based estimator of external wrench and unmodeled dynamics\nYear: 2015\n\nAbstract: A passivity-based control of Vertical Take-off and Landing (VToL) Unmanned Aerial Vehicles (UAVs) is presented in this paper. An estimator of unmodeled dynamics and external wrench (forces plus moments) acting on the aerial vehicle and based on the momentum of the system is employed to compensate such disturbances effects. This arrangement allows VToL UAVs to perform hovering, tracking and aerial manipulation tasks in unstructured environments. A rigorous stability proof is provided under certain assumptions. Experiments are presented to evaluate the performance of the proposed control design. Passivity-based framework is employed within a classical control scheme for UAVs.Control of angular dynamics does not rely upon exact model cancellation.Estimation is directly fed back to the passivity-based controller.Theoretical proofs and experiments are presented to validate the approach.","Title: Tracking Fractures of Deformable Objects in Real-Time with an RGB-D Sensor\nYear: 2015\n\nAbstract: This paper introduces a method able to track in real-time a 3D elastic deformable objects which undergo fractures, using the point cloud data provided by an RGB-D sensor. Our framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered by non-rigidly fitting the mesh, based on the Finite Element Method to physically model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. Fractures are handled by processing the stress tensors computed on the mesh of the FEM model, in order to detect fracturable nodes. Local remeshing around fracturable nodes is then performed to propagate the fracture. The real-time performance of the system is demonstrated on real data involving various deformations and fractures.","Title: Autonomous landing of rotary-wing aerial vehicles by image-based visual servoing in GPS-denied environments\nYear: 2015\n\nAbstract: In this paper we propose a new control method for quadrotor autonomous landing on a visual target without linear velocity measurements. Only onboard sensing is exploited, such that only the images of the landing pad from a down-looking camera, along with data from an Inertial Measurement Unit's gyro, are used. The control system consists of an image-based nonlinear observer that estimates online the linear velocity of the vehicle and a backstepping image-based controller that generates attitude, and thrust setpoints to the quadrotor autopilot. Both observer and controller share the same feedback information: spherical visual features. Therefore no further image elaboration is needed for the estimation. This, along with the fact that only simple computations on low- and constant-dimension arrays are involved, makes the proposed solution computationally cheap. Real-hardware experiments on a quadrotor are carried out to verify the validity of the proposed control system.","Title: Mixed-Initiative Planning and Execution for Multiple Drones in Search and Rescue Missions.\nYear: 2015\n\nAbstract: We present a mixed-initiative planning and execution system for human multi-drones interaction during search and rescue missions. The proposed system should allow a single operator to supervise and orchestrate the operations of a set of UAVs by means of a natural multimodal communication. In particular, we consider the task of searching for missing persons in a real-world alpine scenario. In this context, we assume that the human operator is an alpine rescuer, involved in the scene and co-located with the drones, hence not fully dedicated to the robotic platforms, but only able to provide sparse and sketchy interventions. This scenario requires a framework that supports adjustable autonomy, from explicit teleoperation to a complete autonomy, and an effective and natural mixed-initiative interaction between the human and the robotic team. In this paper, we illustrate the domain and the overall framework discussing the system at work in a simulated case study.","Title: Multimodal Interaction with Multiple Co-located Drones in Search and Rescue Missions.\nYear: 2016\n\nAbstract: We present a multimodal interaction framework suitable for a human rescuer that operates in proximity with a set of co-located drones during search missions. This work is framed in the context of the SHERPA project whose goal is to develop a mixed ground and aerial robotic platform to support search and rescue activities in a real-world alpine scenario. Differently from typical human-drone interaction settings, here the operator is not fully dedicated to the drones, but involved in search and rescue tasks, hence only able to provide sparse, incomplete, although high-value, instructions to the robots. This operative scenario requires a human-interaction framework that supports multimodal communication along with an effective and natural mixed-initiative interaction between the human and the robots. In this work, we illustrate the domain and the proposed multimodal interaction framework discussing the system at work in a simulated case study.","Title: Design, Implementation and Experiments of a Robust Passivity-based Controller for a Rolling-balancing System.\nYear: 2016\n\nAbstract: In this paper, we present the design of a robust interconnection and damping assignment controller for a rolling-balancing system known as the disk-on-disk. The underactuation feature of this system hampers the control design, and since we consider matched disturbances, the problem becomes even more challenging. To overcome this difficulty, we propose to design first a controller to stabilize the desired equilibrium of the case where the disturbance is not present, and then we robustify this controller by adding a nonlinear PID outer loop that compensates the disturbance. Finally, we evaluate the practical applicability of the control design by implementing the controllers on a real hardware for the disk-on-disk system.","Title: An Optimal Trajectory Planner for a Robotic Batting Task: The Table Tennis Example.\nYear: 2016\n\nAbstract: This paper presents an optimal trajectory planner for a robotic batting task . The specific case of a table tennis game performed by a robot is considered. Given an estimation of the trajectory of the ball during the free flight, the method addresses the determination of the paddle configuration (pose and velocity) to return the ball at a desired position with a desired spin. The implemented algorithm takes into account the hybrid dynamic model of the ball in free flight as well as the state transition at the impact (the reset map). An optimal trajectory that minimizes the acceleration functional is generated for the paddle to reach the desired impact position, velocity and orientation. Simulations of different case studies further bolster the approach along with a comparison with state-of-the-art methods.","Title: Implicit Robot Selection For Human Multi-Robot Interaction In Search And Rescue Missions\nYear: 2016\n\nAbstract: We present a system suitable for human multirobot interaction that supports the operator in the robot selection process. The proposed framework allows a human to issue commands to a robotic team without an explicit robot selection in so enabling a fluent interaction. This work is framed in the operative context of the SHERPA project [1], which proposes the deployment of a robotic platform for Search & Rescue in an alpine scenario and assumes the presence of a human rescuer that can orchestrate the robots operations with multimodal commands. In this context, implicit robot selection is mainly motivated by fast communication and the difficulties to distinguish different robots of similar shape in a hazardous environment and in adverse weather conditions. In the proposed approach, each robot of the team can evaluate the probability to be referred in an incomplete command, considering its actual capabilities along with geometrical and contextual information. We describe the overall system architecture focusing on the human intention recognition process. The proposed framework is trained and evaluated in a simulated case study.","Title: Teleoperation of the SCHUNK S5FH under-actuated anthropomorphic hand using human hand motion tracking.\nYear: 2017\n\nAbstract: This paper describes the development of a remote handling control of an anthropomorphic robotic hand, the SCHUNK S5FH, using the human hand as master by measuring its motion with OptiTrack Technology. The goal of this work is to enhance manipulation studies on the human hand and to instantly transfer those studies on robotic hands. A preliminary study on methods and devices used for fingers tracking led to the choice of a simplified kinematic model of the human hand on the basis of the available motion tracking system. Using the same criteria, the analysis of protocols for markers allocation led to define the number and a method for their arrangement on the fingers and palm. In order to overcome the limitation of the Motion Capture System, a method for identification and labeling has been developed according to their anatomical arrangement. Afterwards, the tracking is performed using the constraints between marker positions on the kinematic chain of the hand and a dynamic labeling algorithm robust with respect to noise, outliers and loss of markers. The validation is performed using the right hand of different subjects and considering different tasks involving flexion/extension and abduction/adduction of fingers and thumb opposition. For testing and validation, preliminary studies on synergies for manipulation tasks such as screwing a cup, has been conducted on the human hand and transferred on the robotic hand.","Title: Tracking elastic deformable objects with an RGB-D sensor for a pizza chef robot.\nYear: 2017\n\nAbstract: This paper presents a method for tracking a 3D textureless object which undergoes elastic deformations, using the point cloud data provided by an RGB-D sensor and in real-time. This solution is expected to be useful for enhanced manipulation of humanoid robotic systems, especially in the case of pizza dough to be ideally manipulated by a pizza chef robot. Our tracking framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered first in a rigid manner and then by non-rigidly fitting the mesh, based on the Finite Element Method to model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. The system has been evaluated on synthetic and real data, and by integrating it into manipulation experiments on the RoDyMan1 1\n http://www.rodyman.eu/. The research leading to these results has been supported by the RoDyMan project, which has received funding from the European Research Council(FP7 IDEAS) under Advanced Grant agreement number 320992. The authors are solely responsible for its content. It does not represent the opinion of the European Community and the Community is not responsible for any use that might be made of the information contained therein.humanoid robotic platform.","Title: Orbital stabilization of a VToL UAV for landing on oscillating platforms\nYear: 2016\n\nAbstract: This paper presents preliminary theoretical results about asymptotic orbital stabilization of an aerial vehicle for landing on a periodic oscillating platform. A feedback controller firstly stabilizes a chosen set of virtual geometric constraints. This pushes the dynamics of the aerial vehicle to reach a limit cycle, that is in turn the periodic motion of the landing platform to track. Then, a linear periodic system is considered around the vicinity of the orbit, and it is stabilized through a modified LQR design. Mathematical and theoretical frameworks are presented along with case studies that are critically discussed.","Title: The Effect of Shapes in Input-State Linearization for Stabilization of Nonprehensile Planar Rolling Dynamic Manipulation.\nYear: 2016\n\nAbstract: A control framework for nonprehensile planar rolling dynamic manipulation is derived in this letter. By rotating around the center of mass, the manipulator moves a part without grasping it but exploiting its dynamics. Given some assumptions on the shapes of both the object and the manipulator, a state transformation is found rendering the state-space system in a chain of integrators form without i...","Title: Vision-based and IMU-aided scale factor-free linear velocity estimator.\nYear: 2017\n\nAbstract: This paper presents a new linear velocity estimator based on the unscented Kalman filter and making use of image information aided with inertial measurements. The proposed technique is independent of the scale factor in case of planar observed scene and does not require a priori knowledge of the scene. Image moments of virtual objects, i.e. sets of classical image features such as corners collected online, are employed as the sole correcting information to be fed back to the estimator. Experimental results performed with a quadrotor equipped with a fisheye camera highlight the potential of the proposed approach.","Title: Passivity-Based Control for a Rolling-Balancing System: The Nonprehensile Disk-on-Disk.\nYear: 2017\n\nAbstract: In this brief, we propose a passivity-based control design for a rolling-balancing system called the disk-on-disk (DoD). The stabilization of the desired equilibrium is obtained via energy shaping and damping injection. The DoD is an underactuated mechanical system composed of two disks arranged one on top of the other. The top disk, which we call the object, is free to roll without slipping on the lower disk, which we call the hand. The hand is actuated by a controlled torque, while the object is unactuated. The control objective is to balance the object at the upright position and drive the hand to a desired angle. We design an energy shaping controller without solving the partial differential equations, which rise from the matching equation. We assess the performance of the controller by both simulations and experiment results, which also verify the practical applicability of the design approach.","Title: A robust multimodal fusion framework for command interpretation in human-robot cooperation\nYear: 2017\n\nAbstract: We present a novel multimodal interaction framework supporting robust human-robot communication. We consider a scenario where a human operator can exploit multiple communication channels to interact with one or more robots in order to accomplish shared tasks. Moreover, we assume that the human is not fully dedicated to the robot control, but also involved in other activities, hence only able to interact with the robotic system in a sparse and incomplete manner. In this context, several human or environmental factors could cause errors, noise and wrong interpretations of the commands. The main goal of this work is to improve the robustness of human-robot interaction systems in similar situations. In particular, we propose a multimodal fusion method based on the following steps: for each communication channel, unimodal classifiers are firstly deployed in order to generate unimodal interpretations of the human inputs; the unimodal outcomes are then grouped into different multimodal recognition lines, each representing a possible interpretation of a sequence of multimodal inputs; these lines are finally assessed in order to recognize the human commands. We discuss the system at work in a case study in which a human rescuer interacts with a team of flying robots during Search & Rescue missions. In this scenario, we present and discuss real world experiments to demonstrate the effectiveness of the proposed framework.","Title: Control of redundant robot arms with null-space compliance and singularity-free orientation representation.\nYear: 2018\n\nAbstract: This paper tackles the problem of controlling the position and orientation, expressed in a singularity-free representation form, of the end-effector of a redundant robot, while addressing an active compliant behaviour within the null-space. The manuscript extends the work in Sadeghian et al. (2014) by explicitly addressing the orientation part. In order to successfully accomplish the task, a dynamic controller is designed without need of any exteroceptive sensors information. A rigorous stability analysis is provided to confirm the developed theory. Experiments are finally carried out to bolster the performance of the proposed approach.","Title: Nonprehensile Manipulation of an Underactuated Mechanical System With Second-Order Nonholonomic Constraints: The Robotic Hula-Hoop.\nYear: 2018\n\nAbstract: A mechanical system consisting of a hoop and a pole is considered, for which the corresponding dynamic model represents an underactuated system subject to second-order nonholonomic constraints. The pursued goal is to simultaneously track a trajectory in the unactuated coordinates and to stabilize the actuated ones. For the model under consideration, the well-known noncollocated partial feedback li...","Title: Introduction To The Special Issue On Aerial Manipulation\nYear: 2018\n\nAbstract: The papers in this special section focus on aerial manipulation which is intended as grasping, positioning, assembling and disassembling of mechanical parts, measurement instruments and any other kind of objects, performed by a flying robot equipped with arms and grippers. Aerial manipulators can be helpful in those industrial and service applications that are considered very dangerous for a human operator. For instance, think of tasks like the inspection of a bridge, the inspection and the fixing-up of high-voltage electric lines, the repairing of rotor blades and so on. These tasks are both very unsafe and expensive because they require the performance of professional climbers and/or specialists in the field. A drone with manipulation capabilities can instead assist the human operator in these jobs or, at least, in the most hazardous and critical situations. As a matter of fact, such devices can indeed operate in dangerous tasks like reaching the bottom of the deck of a bridge or the highest places of a plant or a building; they can avoid dangerous work at height; aerial platforms can increase the total number of inspections of a plant, monitoring the wear of the components. Without doubts, aerial manipulation will improve the quality of the job of many workers.","Title: Nonprehensile Dynamic Manipulation: A Survey.\nYear: 2018\n\nAbstract: Nonprehensile dynamic manipulation can be reasonably considered as the most complex manipulation task. It might be argued that such a task is still rather far from being fully solved and applied in robotics. This survey tries to collect the results reached so far by the research community about planning and control in the nonprehensile dynamic manipulation domain. A discussion about current open i...","Title: Image-Based Visual-Impedance Control of a Dual-Arm Aerial Manipulator.\nYear: 2018\n\nAbstract: Three new image-based visual-impedance control laws are proposed in this letter allowing physical interaction of a dual-arm unmanned aerial manipulator equipped with a camera and a force/torque sensor. Namely, two first-order impedance behaviors are designed based on the transpose and the inverse of the system Jacobian matrix, respectively, while a second-order impedance behavior is carried out as...","Title: Nonprehensile Manipulation of Deformable Objects: Achievements and Perspectives from the Robotic Dynamic Manipulation Project.\nYear: 2018\n\nAbstract: The goal of this article is to disseminate the planning and control strategies for robotic nonprehensile manipulation results achieved so far with the Robotic Dynamic Manipulation (RoDyMan) project. The goal of the project is to advance the state of the art of nonprehensile dynamic manipulation of rigid and deformable objects to enhance the possibility of employing robots in anthropic environments. RoDyMan projectu0027s final demonstration will be acting as an autonomous pizza maker. This article highlights the lessons learned and paves the way toward critical discussions and future research.","Title: Capturing Deformations of Interacting Non-rigid Objects Using RGB-D Data\nYear: 2018\n\nAbstract: This paper presents a method for tracking multiple interacting deformable objects undergoing rigid motions, elastic deformations and contacts, using image and point cloud data provided by an RGB-D sensor. A joint registration frame-work is proposed, based on physical Finite Element Method (FEM) elastic and interaction models. It first relies on a visual segmentation of the considered objects in the RGB images. The different segmented point clouds are then processed to estimate rigid transformations with on an ICP algorithm, and to determine geometrical point-to-point correspondences with the meshes. External forces resulting from these correspondences and between the current and the rigidly transformed mesh can then be derived. It provides both non-rigid and rigid data cues. A classical collision detection and response model is also integrated, giving contact forces between the objects. The deformations of the objects are estimated by solving a dynamic system balancing these external and contact forces with the internal or regularization forces computed through the FEM elastic model. This approach has been here tested on different scenarios involving two or three interacting deformable objects of various shapes, with promising results.","Title: A control architecture for multiple drones operated via multimodal interaction in search & rescue mission\nYear: 2016\n\nAbstract: An architecture suitable for the control of multiple unmanned aerial vehicles deployed in Search & Rescue missions is presented in this paper. In the proposed system, a single colocated human operator is able to coordinate the actions of a set of robots in order to retrieve relevant information of the environment. This work is framed in the context of the SHERPA project whose goal is to develop a mixed ground and aerial robotic platform to support search and rescue activities in alpine scenario. Differently from typical human-drone interaction settings, here the operator is not fully dedicated to the drones, but involved in search and rescue tasks, hence only able to provide sparse and incomplete instructions to the robots. In this work, the domain, the interaction framework and the executive system for the autonomous action execution are discussed. The overall system has been tested in a real world mission with two drones equipped with on-board cameras.","Title: Attentional Multimodal Interface For Multidrone Search In The Alps\nYear: 2016\n\nAbstract: We present a multimodal attentional interface suitable for a human operator that monitors and controls the activities of a team of drones during search and rescue missions. We consider a scenario where the operator is a component of the rescue team, hence not fully dedicated to the robots, but only able to interact with them with sparse and incomplete commands. In this context, an adaptive interface is needed to support the user situation awareness and to enable an effective interaction with the drones. In this work, we propose a multimodal attention-based interface designed for this domain. This framework is to filter the information flow towards the operator selecting and adapting the communication mode according to the context and the human state. We illustrate the features of the adaptive system along with an initial assessment in a simulated scenario.","Title: On the Experiments About the Nonprehensile Reconfiguration of a Rolling Sphere on a Plate\nYear: 2018\n\nAbstract: A method to reconfigure in a nonprehensile way the pose (position and orientation) of a sphere rolling on a plate is proposed in this letter. The nonholonomic nature of the task is first solved at a planning level, where a geometric technique is employed to derive a Cartesian path to steer the sphere towards the arbitrarily desired pose. Then, an integral passivity-based control is designed to track the planned trajectory. The port-Hamiltonian formalism is employed to model the whole dynamics. Two approaches to move the plate are addressed in this paper, showing that only one of them allows the full controllability of the system. A humanoid-like robot is employed to bolster the proposed method experimentally.","Title: Control of the TORA System through the IDA-PBC without Explicit Solution of Matching Equations\nYear: 2019\n\nAbstract: This paper presents the control of a translational oscillator with a rotational actuator (TORA) system, in full gravity, through the interconnection and damping assignment passivity-based control (IDA-PBC). The sought goal is to control the underactuated TORA system while reducing the complexity in solving the partial differential equations coming out from the so-called matching equations, which arise from the IDA-PBC. The performance of the designed controller is illustrated through numerical simulations.","Title: Control of Nonprehensile Planar Rolling Manipulation: A Passivity-Based Approach.\nYear: 2019\n\nAbstract: This paper presents a new procedure to design a control law using the classical interconnection and damping assignment technique within the passivity-based port-Hamiltonian framework. The sought goal is to reduce the complexity of solving the so-called matching equations. The proposed approach is applied to two case studies of planar rolling nonprehensile manipulation, namely, the ball-and-beam an...","Title: 6D Pose Task Trajectory Tracking for a Class of 3D Aerial Manipulator From Differential Flatness\nYear: 2019\n\nAbstract: In this paper, the dynamics and control of a novel class of aerial manipulator for the purpose of end effector full pose trajectory tracking are investigated. The 6D pose of the end effector is set as a part of the flat output, from which the conditions that the system has the proposed flat output is obtained. The control law for the end effector tracking purpose is designed. The core part of the controller is an almost global controller in the configuration space of the system. From the transformation between the state space and the output space, the tracking control of the end effector in SE (3) is also achieved. The stability of the controlled system is analyzed. A numerical example is presented to demonstrate the theoretical analysis.","Title: A Novel Articulated Rover For Industrial Pipes Inspection Tasks\nYear: 2021\n\nAbstract: Inspection and maintenance of industrial pipes using robots represent an emerging application in Oil & Gas and refinery facilities for Nondestructive Tests (NDT). In this work, we present the design and development of a novel articulated mobile robot able to safely navigate over straight and curved pipes for inspection tasks. This rover is meant to be the base of the hybrid aerial-ground platform of the HYFLIERS project that aims to develop novel solutions to perform inspection measurements with reduced exposure to risks and costs. Thanks to the multiple degrees of freedom and onboard sensors, the rover proposed in this paper can stabilize and navigate on a pipe across welding and over curves. After discussed the mechanical design of the rover, we demonstrate its effectiveness in the localization and navigation of curved pipes.","Title: Energy pumping-and-damping for gait robustification of underactuated planar biped robots within the hybrid zero dynamics framework\nYear: 2021\n\nAbstract: This paper addresses the robust gait control for planar and passive biped robots using approaches based on energy properties. Energy pumping-and-damping passivity-based control is used to increase the robustness against uncertainties on the initial conditions of the passive gait exhibited by planar biped robots. The stability analysis is carried out by exploiting the system’s passivity and the hyb...","Title: Robust Visual Localization of a UAV Over a Pipe-Rack Based on the Lie Group SE(3)\nYear: 2022\n\nAbstract: Visual inspection and maintenance ofindustrialpipes using robots represent an emerging application in Oil & Gas and refinery facilities. In this domain, we present a pose tracking system based on a single camera sensor to localize an unmanned aerial vehicle operating over a pipe-rack to carry out inspection activities. We propose a unified framework based on the Lie group SE(3) which allows the simultaneous estimation of the pose of the UAV along with some parameters of the pipe-rack model. Numerical simulations have been performed to demonstrate the effectiveness of the proposed approach.","Title: A hardware-in-the-loop simulator for physical human-aerial manipulator cooperation\nYear: 2021\n\nAbstract: A hardware-in-the-loop simulator for human cooperation with an aerial manipulator is presented in this paper. The simulator provides the user with realistic haptic feedback proper of a human-aerial manipulator interaction activity. The forces exchanged between the hardware interface and the human/environment are measured and supplied to a dynamically simulated aerial manipulator. In turn, the simulated aerial platform feeds back its position to the hardware allowing the human to feel and evaluate the interaction effects. Besides human-aerial manipulator cooperation, the simulator lends itself to developing and testing autonomous control strategies in aerial manipulation. Therefore, the effectiveness of the proposed system is evaluated along with two case studies: a collaborative task where the human operator attaches a tool to the robot end-effector and an autonomous bird diverter installation task.","Title: Transfer from existing flight control of under-actuated aerial vehicles to interaction control of aerial slung load systems\nYear: 2021\n\nAbstract: This paper investigates a framework to design the interaction control of the aerial slung load system which is composed of an underactuated aerial vehicle, a cable, and a load. Instead of designing new controller for the system, we show that the interaction control of the system can be totally transferred from the controllers for under-actuated aerial systems. Selecting the differentially flat output as the configuration, the equation of motion of the two systems is written in the same format. The flight controller of the under-actuated aerial vehicle is thus migrated to control the aerial slung load system. We adopt the admittance filter to generate the compliant trajectory of the load under external interaction force. Furthermore, from the boundedness of the vehicle attitude tracking error and the external force estimation error, the convergence of the entire system is proved. Based on this theoretical foundation, an example interaction controller for the aerial slung load is derived from an existing flight controller directly, by including an external force estimator. The example controller is demonstrated in the numerical simulation.","Title: Visual control through narrow passages for an omnidirectional wheeled robot\nYear: 2022\n\nAbstract: Robotic systems are gradually replacing human intervention in dangerous facilities to improve human safety and prevent risky situations. In this domain, our work addresses the problem of autonomous crossing narrow passages in a semi-structured (i.e., partially-known) environment. In particular, we focus on the CERN’s Super Proton Synchrotron particle accelerator, where a mobile robot platform is equipped with a lightweight arm to perform measurements, inspection, and maintenance operations. The proposed approach leverages an image-based visual servoing strategy that exploits computer vision to detect and track known geometries defining narrow passage gates. The effectiveness of the proposed approach has been demonstrated in a realistic mock-up."],"string":"[\n \"Title: Managing redundant visual measurements for accurate pose tracking\\nYear: 2003\\n\\nAbstract: This paper proposes an algorithm for managing redundant measurements provided by a stereo multi-camera system to achieve accurate visual tracking of a moving object. Self-occlusion, different visual resolution zones and optimal selection of redundant measurements are some of the problems addressed. The algorithm uses the extended Kalman filter embedded in a computational efficient pose estimation procedure based on Binary Space Partitioning Tree geometric modelling of 3D objects. Experimental results are presented for the case of an object moving in the visual space of two fixed cameras.\",\n \"Title: An Open Architecture For Sensory Feedback Control Of A Dual-Arm Industrial Robotic Cell\\nYear: 2007\\n\\nAbstract: Purpose - To present an open architecture for real-time sensory feedback control of a dual-arm industrial robotic cell. The setup is composed of two industrial robot manipulators equipped with force/torque sensors and pneumatic grippers, a vision system and a belt conveyor,Design/methodology/approach - The original industrial robot controllers have been replaced by a single PC with software running under a real-time variant of the Linux operative system.Findings - The new control architecture allows advanced control schemes to be developed and tested for the single robots and for the dual-arm robotic cell, including force control and visual servoing tasks.Originality/value - An advanced user interface and a simulation environment have been developed, which permit fast, safe and reliable prototyping of planning and control algorithms.\",\n \"Title: Floating Visual Grasp of Unknown Objects Using an Elastic Reconstruction Surface\\nYear: 2009\\n\\nAbstract: In this paper a new method for fast visual grasp of unknown objects is presented. The method is composed of an object surface reconstruction algorithm and of a local grasp planner, evolving in a parallel way. The reconstruction algorithm makes use of images taken by a camera carried by the robot, mounted in an eye-in-hand configuration. An elastic reconstruction sphere, composed by masses interconnected each other by springs, is virtually placed around the object. The sphere is let to evolve dynamically under the action of external forces, which push the masses towards the object centroid. To smoothen the surface evolution, spatial dampers are attached to each mass. The reconstruction surface shrinks toward its center of mass until some pieces of its surface intercept the object visual hull, and thus local rejection forces are generated to push out the reconstruction points until they stay into the visual hull. This process shapes the sphere around the unknown object. Running in parallel to the reconstruction algorithm, the grasp planner moves the fingertips, floating on the current available reconstructed surface, according to suitable quality measures. The fingers keep moving towards local minima depending on the evolution of the reconstruction surface deformation. The process stops when the object has been completely reconstructed and the planner reaches a local minimum. Quality measures considering both hand and grasp proprieties are adopted. Simulations are presented, showing the effectiveness of the proposed algorithm.\",\n \"Title: A Position-Based Visual Impedance Control for Robot Manipulators\\nYear: 2007\\n\\nAbstract: In this paper, an approach to interaction control of a robot manipulator with a partially known environment is proposed. The environment is a rigid object of known geometry but of unknown and possibly time-varying position and orientation. An algorithm for online estimation of the object pose is adopted, based on visual data provided by a camera as well as on forces and moments measured during the interaction with the environment. This algorithm is embedded into an impedance control scheme, resulting in a position-based visual impedance control. Experimental results are presented for the case of an industrial robot manipulator in contact with a planar surface.\",\n \"Title: Visual tracking of multiple objects using binary space partitioning trees\\nYear: 2003\\n\\nAbstract: The use of visual sensors may have high impact in robotic applications where it is required to measure the pose (position and orientation) and the visual features of objects moving in unstructured environments. In this paper, the problem of real-time estimation of the position and orientation of of multiple objects is considered. Special emphasis is devoted to the case when two or more objects overlap with respect to the visual system causing occlusion. The algorithm is based on the Kalman filtering and Binary Space Partition (BSP) tree representations of the objects geometry. The real-time implementation of the algorithm is experimentally tested for the case of visual tracking of two objects using two cameras.\",\n \"Title: An Occlusion Prediction Algorithm For Visual Servoing Tasks In A Multi-Amt Robotic Cell\\nYear: 2005\\n\\nAbstract: This paper presents a new approach to the prediction of visual occlusions for a robotic system performing visual servoing tasks. The case of a multi-arm robotic cell equipped with a multi-camera eye-to-hand visual system is considered. The proposed approach is able to predict the self occlusions as well as the mutual occlusions caused by the robot links and tools. The algorithm is based on the geometric representation of the cell in terms of a BSP tree, assuming that the CAD geometry of the objects and the kinematic model of the multi-arm robotic system are known. Experimental results are presented for the case of two industrial robots performing a vision-guided grasping task.\",\n \"Title: A grasping force optimization algorithm for dexterous robotic hands.\\nYear: 2012\\n\\nAbstract: The problem of grasping force optimization for a robotic system equipped with multi-fingered hands is considered in this paper. This problem is cast as a convex optimization problem, considering also joint torque constraints. A solution suitable for on-line implementation is proposed, which allows a substantial reduction of the computational load by dynamically decreasing the number of active torque constraints. Moreover, for the case of a bimanual manipulation system, a sub-optimal single-hand optimization algorithm is presented and compared with the optimal one. The effectiveness of the described methods has been tested in a simulation case study.\",\n \"Title: Mav Indoor Navigation Based On A Closed-Form Solution For Absolute Scale Velocity Estimation Using Optical Flow And Inertial Data\\nYear: 2011\\n\\nAbstract: A new vision-based obstacle avoidance technique for indoor navigation of Micro Aerial Vehicles (MAVs) is presented in this paper. The vehicle trajectory is modified according to the obstacles detected through the Depth Map of the surrounding environment, which is computed online using the Optical Flow provided by a single onboard omnidirectional camera. An existing closed-form solution for the absolute-scale velocity estimation based on visual correspondences and inertial measurements is generalized and here employed for the Depth Map estimation. Moreover, a dynamic region-of-interest for image features extraction and a self-limitation control for the navigation velocity are proposed to improve safety in view of the estimated vehicle velocity. The proposed solutions are validated by means of simulations.\",\n \"Title: Robust Visual Tracking Using A Fixed Multi-Camera System\\nYear: 2003\\n\\nAbstract: The problem of tracking the position and orientation of a moving object using a stereo camera system is considered in this paper. A robust algorithm based on the extended Kalman filter is adopted, combined with an efficient selection technique of the object image features, based on Binary Space Partitioning tree geometric models. An experimental study is carried out using a vision system of two fixed cameras.\",\n \"Title: Multi-fingered grasp synthesis based on the object dynamic properties.\\nYear: 2013\\n\\nAbstract: The grasping and manipulation of objects, especially when they are heavy with respect to the hand power capability, requires the synthesis of grasp configurations that explicitly take into account the dynamic properties of the object. Specifically, suitable grasp configurations reducing gravitational and inertial effects during object manipulation, and minimizing and equally distributing the grasping forces among all the available fingers, must be computed. A new method for fast synthesis of multi-fingered grasp configurations is proposed in this paper. In particular, to reduce the computational complexity, all the regions of the object surface favoring the synthesis of minimal inertia grasps are evaluated first. Then, a reduced number of discrete grasping regions are selected on the basis of the fingertip size, model uncertainty, and surface curvature. Finally, an exhaustive search of the optimal grasp configurations with respect to the grasp quality is performed. Several case studies and comparisons with other methods are proposed to demonstrate the effectiveness of the proposed approach.\",\n \"Title: Surface model reconstruction of 3D objects from multiple views\\nYear: 2009\\n\\nAbstract: A points surface reconstruction algorithm of 3D object models from multiple silhouettes is proposed in this paper. Some images of the target object are taken from a circular trajectory by a robot with a camera mounted in an eye-in-hand configuration. The silhouettes of the observed object are evaluated for each view using a blob analysis process, and from those a set of points that sample a reconstruction sphere surrounding the target object are estimated. The sphere sample points are attracted by the object center of mass using a variable step according to the distance from the silhouettes contours. For each point, the iterative process of constriction is stopped when all the back-projections of the point are within the corresponding silhouettes. Moreover, a new method based on a rough estimation of object dimension is proposed to reduce the disturbances due to projection and shadow cones. Simulations and experiments are presented to evaluate the performance of the proposed algorithm.\",\n \"Title: Floating visual grasp of unknown objects\\nYear: 2009\\n\\nAbstract: A new method for fast visual grasp of unknown objects using a camera mounted on a robot in an eye-in-hand configuration is presented. The method is composed of a fast iterative object surface reconstruction algorithm and of a local grasp planner, evolving in a synchronized parallel way. The reconstruction algorithm makes use of images taken by a camera carried by the robot. A reconstruction sphere, virtually placed around the object, is iteratively compressed towards the object visual hull, dragging out the fingers attached to it. Between two steps of the reconstruction process, the planner moves the fingers, floating on the current reconstructed surface, according to suitable quality measures. The fingers keep moving until a local minimum is achieved, then a new object surface estimation provided by the reconstruction process is considered. Quality measures considering both hand and grasp proprieties are adopted. Simulations are presented to show the performance of the proposed algorithm.\",\n \"Title: Airobots: Innovative Aerial Service Robots For Remote Inspection By Contact\\nYear: 2013\\n\\nAbstract: This video presents experiments conducted within the final review meeting demonstration session of the AIRobots project. AIRobots started at 2010 and the final review meeting took place on 22 of March, 2013. The presented experiments cover a wide area of the challenges related with aerial industrial inspection. In particular, multiple test- cases related with both vision- based and contact- based inspection and in general physical interaction are shown. It is highlighted that these experiments were recorded live during the project demonstration and evaluation process.\",\n \"Title: Grasp planning and parallel control of a redundant dual-arm/hand manipulation system.\\nYear: 2013\\n\\nAbstract: In this paper, a kinematic model of a dual-arm/hand robotic system is derived, which allows the computation of the object position and orientation from the joint variables of each arm and each finger as well as from a suitable set of contact variables. On the basis of this model, a motion planner is designed, where the kinematic redundancy of the system is exploited to satisfy some secondary tasks aimed at ensuring grasp stability and manipulation dexterity without violating physical constraints. To this purpose, a prioritized task sequencing with smooth transitions between tasks is adopted. Afterwards, a controller is designed so as to execute the motion references provided by the planner and, at the same time, achieve a desired contact force exerted by each finger on the grasped object. To this end, a parallel position/force control is considered. A simulation case study has been developed by using the dynamic simulator GRASPIT!, which has been suitably adapted and redistributed.\",\n \"Title: A Framework for Force and Visual Control of Robot Manipulators\\nYear: 2007\\n\\nAbstract: A framework for force and visual control of robot manipulators in contact with a partially known environment is proposed. The environment is modelled as a rigid object of known geometry but of unknown and time-varying pose. An algorithm or online estimation of the object pose is adopted; based on visual data as well as on force measurements. This information is used by a force/position controller. The resulting control scheme has a inner/outer structure where the outer loop performs pose estimation and the inner loop is devoted to interaction control.\",\n \"Title: Aerial service vehicles for industrial inspection: task decomposition and plan execution\\nYear: 2013\\n\\nAbstract: This work proposes a high-level control system designed for an Aerial Service Vehicle capable of performing complex tasks in close and physical interaction with the environment in an autonomous manner. We designed a hybrid control architecture which integrates task, path, motion planning/replanning, and execution monitoring. The high-level system relies on a continuous monitoring and planning cycle to suitably react to events, user interventions, and failures, communicating with the low level control layers. The system has been assessed on real-world and simulated scenarios representing an industrial environment.\",\n \"Title: Real-time visual tracking based on BSP-tree representations of object boundary\\nYear: 2005\\n\\nAbstract: In this paper an algorithm for real-time estimation of the position and orientation of a moving object using a video camera is presented. The algorithm is based on the extended Kalman filter which iteratively computes the object pose from the position measured in the image plane of a set of feature points of the object. A new technique is proposed for the selection of the optimal feature points based on the representation of the object geometry by means of a Binary Space Partitioning (BSP) tree. At each sample time, a visit algorithm of the tree allows pre-selecting all the feature points of the object that are visible from the camera in the pose predicted by the Kalman filter. A further selection is performed to find the optimal set of visible points to be used for image feature extraction. Experimental results are presented which confirm the feasibility and effectiveness of the proposed technique.\",\n \"Title: Robot Interaction Control Using Force And Vision\\nYear: 2006\\n\\nAbstract: The problem of interaction control of a robot manipulator with a partially known environment is considered. The environment is a rigid object of known geometry but of unknown and possibly time varying position and orientation. An algorithm for online estimation of the object pose is presented, based on visual data provided by a camera. The estimation accuracy is improved during the interaction by using also force and joint position measurements. The proposed method can be exploited to implement any kind of interaction control strategy. A simulation case study is considered for the case of impedance control of a robot manipulator in contact with a planar surface.\",\n \"Title: Visual And Inertial Multi-Rate Data Fusion For Motion Estimation Via Pareto-Optimization\\nYear: 2013\\n\\nAbstract: Motion estimation is an open research field in control and robotic applications. Sensor fusion algorithms are generally used to achieve an accurate estimation of the vehicle motion by combining heterogeneous sensors measurements with different statistical characteristics. In this paper, a new method that combines measurements provided by an inertial sensor and a vision system is presented. Compared to classical model-based techniques, the method relies on a Pareto optimization that trades off the statistical properties of the measurements. The proposed technique is evaluated with simulations in terms of computational requirements and estimation accuracy with respect to a classical Kalman filter approach. It is shown that the proposed method gives an improved estimation accuracy at the cost of a slightly increased computational complexity.\",\n \"Title: Robotic Ball Catching with an Eye-in-Hand Single-Camera System\\nYear: 2015\\n\\nAbstract: In this paper, a unified control framework is proposed to realize a robotic ball catching task with only a moving single-camera (eye-in-hand) system able to catch flying, rolling, and bouncing balls in the same formalism. The thrown ball is visually tracked through a circle detection algorithm. Once the ball is recognized, the camera is forced to follow a baseline in the space so as to acquire an initial dataset of visual measurements. A first estimate of the catching point is initially provided through a linear algorithm. Then, additional visual measurements are acquired to constantly refine the current estimate by exploiting a nonlinear optimization algorithm and a more accurate ballistic model. A classic partitioned visual servoing approach is employed to control the translational and rotational components of the camera differently. Experimental results performed on an industrial robotic system prove the effectiveness of the presented solution. A motion-capture system is employed to validate the proposed estimation process via ground truth.\",\n \"Title: Robot Vision: Obstacle-Avoidance Techniques for Unmanned Aerial Vehicles.\\nYear: 2013\\n\\nAbstract: In this article, a vision-based technique for obstacle avoidance and target identification is combined with haptic feedback to develop a new teleoperated navigation system for underactuated aerial vehicles in unknown environments. A three-dimensional (3-D) map of the surrounding environment is built by matching the keypoints among several images, which are acquired by an onboard camera and stored in a buffer together with the corresponding estimated odometry. Hence, based on the 3-D map, a visual identification algorithm is employed to localize both obstacles and the desired target to build a virtual field accordingly. A bilateral control system has been developed such that an operator can safely navigate in an unknown environment and perceive it by means of a vision-based haptic force-feedback device. Experimental tests in an indoor environment verify the effectiveness of the proposed teleoperated control.\",\n \"Title: Monocular Eye-In-Hand Robotic Ball Catching with Parabolic Motion Estimation.\\nYear: 2012\\n\\nAbstract: A monocular robotic ball catching system is presented in this paper. A visual servoing control is used in order to keep a thrown ball in the field of view of an eye-in-hand camera and generate a robot motion toward the ball interception point. Simultaneously, the 3D ball trajectory is estimated with a least-squares method, which employs only information provided by the available camera. Experiments demonstrate the feasibility of the proposed approach.\",\n \"Title: Task priority control for aerial manipulation\\nYear: 2014\\n\\nAbstract: This paper presents a task oriented control strategy for aerial vehicles equipped with a manipulator. A camera is attached to the end-effector of the manipulator to perform a primary task consisting on visual servoing towards a desired target. Over-actuation of the whole quadrotor-arm system is exploited to achieve secondary velocity tasks. One subtask is proposed to horizontally stabilize the platform during flight by aligning the arm center of gravity with the quadrotor gravitational vector. The arm singularities and manipulability are addressed by another subtask that leads the arm to a preferable configuration, and also takes into account the arm joint limits. The performance of the whole visual servo and secondary tasks control scheme is shown in a Robot Operating System (ROS) implementation.\",\n \"Title: Image moments-based velocity estimation of UAVs in GPS denied environments\\nYear: 2014\\n\\nAbstract: This paper proposes a new method for quadrotor translational velocity estimation using only onboard sensing and without any prior knowledge on the geometry of the scene. Image moments extracted from the onboard camera images, together with onboard IMU data, are exploited in an Unscented Kalman filter (UKF). Differently with respect to the literature approaches, the proposed method is independent from the scale factor when considering a planar visual object. The estimation algorithm, in addition of involving matrices of constant size, does not require a well-textured environment, but can rather operate with few visual features. This makes it computationally-cheap, thus appealing for onboard applications. Experiments on a flying real quadrotor are carried out in a GPS-denied and poorly-textured environment in order to verify the validity of the proposed approach as well as its robustness to measurement noises and errors.\",\n \"Title: Emergency landing for a quadrotor in case of a propeller failure: A backstepping approach\\nYear: 2014\\n\\nAbstract: A backstepping approach is proposed in this paper to cope with the failure of a quadrotor propeller. The presented methodology supposes to turn off also the motor which is opposite to the broken one. In this way, a birotor configuration with fixed propellers is achieved. The birotor is controlled to follow a planned emergency landing trajectory. Theory shows that the birotor can reach any point in the Cartesian space losing the possibility to control the yaw angle. Simulation tests are employed to validate the proposed controller design.\",\n \"Title: Emergency landing for a quadrotor in case of a propeller failure: A PID based approach\\nYear: 2014\\n\\nAbstract: A controller dealing with the failure of a quadrotor's motor is presented in this paper. Supposing that the failure has been already detected by the system, the quadrotor is modelled as a birotor with fixed propellers and it is controlled to follow a planned emergency landing trajectory. Theory shows that, in such a configuration, the aerial vehicle is allowed to reach any position in the Cartesian space dropping the possibility to control the yaw angle. Simulations are presented to confirm the presented methodology.\",\n \"Title: Image-based control for dynamically cross-coupled aerial manipulation\\nYear: 2014\\n\\nAbstract: Manipulation tasks carried out with aerial platforms composed of a UAV and a robotic arm involve cross-coupled dynamics between these subsystems. This paper proposes a new controller for this class of aerial robotic systems that allows regulating on velocity commands generated by an outer image-based visual-servo scheme. The controller, that considers the full dynamics of the system, is designed based on the integral backstepping approach. Visual feedback provided by an onboard camera is employed into a new visual servo scheme to simultaneously generate velocity commands for the UAV and the manipulator so that a visual target is reached. The control system takes into account the under-actuation related to rotary-wing vehicles, while at the same time it exploits the functionality system redundancy to achieve the task. Simulation results validate the proposed control system, as well as its robustness to large modeling error and measurement noise.\",\n \"Title: Impedance control of VToL UAVs with a momentum-based external generalized forces estimator\\nYear: 2014\\n\\nAbstract: An estimator of external generalized forces (force plus moments) acting on aerial platforms, and based on the momentum of the mechanical system, is proposed for the control of VToL UAVs together with a hierarchical architecture separating the translational and rotational dynamics of the vehicle. The closed-loop system equations are shaped as mechanical impedances, programmable through the controller gains, and forced by the residuals given by the estimation error. This arrangement allows the VToL UAVs to perform hovering and tracking tasks without a precise knowledge of the vehicle dynamics and in presence of external disturbances and unmodeled aerodynamic effects. Experiments are presented to evaluate the performance of the proposed control design.\",\n \"Title: Objects motion estimation via BSP tree modeling and Kalman filtering of stereo images\\nYear: 2002\\n\\nAbstract: In this paper a computationally efficient algorithm for real time estimation of the position and orientation of moving objects from visual measurements of a system of fixed cameras is proposed. The algorithm is based on extended Kalman filtering of the measurements of the position of suitable feature points selected on the target objects. The effectiveness of the algorithm is improved by using a pre-selection method of the feature points which takes advantage of the Kalman filter prediction capability combined with a BSP tree modeling technique of the objects geometry. Computer simulations are presented to test the performance of the estimation process in the presence of noise, different types of lens geometric distortion, quantization and calibration errors\",\n \"Title: A new method of image features pre-selection for real-time pose estimation based on Kalman filter\\nYear: 2002\\n\\nAbstract: The problem of real-time pose estimation of moving objects using a stereo video camera system is considered in this paper. A computationally efficient algorithm is proposed based on Kalman filtering of the position measurements of suitable feature points selected on the target objects. The efficiency of the algorithm is improved by adopting a new pre-selection technique of the feature points, based on binary space partition (BSP) trees, which takes advantage of the Kalman filter prediction capability. Computer simulations are presented.\",\n \"Title: Coping with occlusions in visual tracking of multiple objects\\nYear: 2003\\n\\nAbstract: The problem of visual tracking of multiple objects is considered in this paper. Special emphasis is devoted to the case when two or more objects overlap with respect to the visual system causing occlusion. The algorithm is based on the Kalman filtering and binary space partition tree representations of the objects geometry. The real-time implementation of the algorithm is experimentally tested for the case of visual tracking of two objects using two cameras.\",\n \"Title: Visual motion estimation of 3D objects: an adaptive extended Kalman filter approach\\nYear: 2004\\n\\nAbstract: An algorithm for the visual estimation of the pose of a moving object is presented in this paper. The algorithm exploits the prediction capability of the extended Kalman Filter to realize in real time a dynamic optimal selection of the object image features used for pose estimation. The robustness of the system with respect to the measurement noise and modelling errors is enhanced by using an adaptive scheme. Experimental case studies are presented to prove the effectiveness of the proposed approach.\",\n \"Title: RePLiCS: an environment for open real-time control of a dual-arm industrial robotic cell based on RTAI-Linux\\nYear: 2005\\n\\nAbstract: An environment for open real-time control of an industrial robotic cell is presented in this paper. The experimental setup is composed of two industrial robot manipulators equipped with force/torque sensors and pneumatic grippers, a vision system and a belt conveyor. The original industrial robot controllers have been replaced by a single PC with software running under a real-time variant of the Linux operative system. The new control environment allows advanced control schemes to be developed and tested for the single robots and for the dual-arm robotic cell, including force control and visual servoing tasks. An advanced user interface and a simulation environment have been developed, which permit fast, safe and reliable prototyping of planning and control algorithms.\",\n \"Title: 3D pose estimation for robotic applications based on a multi-camera hybrid visual system\\nYear: 2006\\n\\nAbstract: An algorithm for the estimation of the position and orientation of a moving object using a hybrid eye-in-hand/eye-to-hand multi-camera system is presented. Based on the extended Kalman filter, this approach exploits the data provided by all the cameras without \\\"a priori\\\" discrimination, allowing real-time estimation. The proposed formulation can be used with different kinds of image features and different representations of the object orientation. A simulation case study is reported to test the feasibility and the effectiveness of the proposed technique\",\n \"Title: 3D monocular robotic ball catching with an iterative trajectory estimation refinement\\nYear: 2012\\n\\nAbstract: In this paper, a 3D robotic ball catching algorithm which employs only an eye-in-hand monocular visual-system is presented. A partitioned visual servoing control is used in order to generate the robot motion, keeping always the ball in the field of view of the camera. When the ball is detected, the camera mounted on the robot end-effector is commanded to follow a suitable baseline in order to acquire measurements and provide a first possible interception point through a linear estimation process. Thereafter, further visual measures are acquired in order to continuously refine the previous prediction through a non-linear estimation process. Experimental results show the effectiveness of the proposed solution.\",\n \"Title: A Grasping Force Optimization Algorithm for Multiarm Robots With Multifingered Hands\\nYear: 2013\\n\\nAbstract: The computation of the grasping forces for a multiarm robotic manipulation system (e.g., an anthropomorphic bimanual system) is considered in this paper. This problem is formulated as a convex optimization problem, also considering joint torque constraints. An algorithmic solution suitable for online implementation is presented, which allows a substantial reduction in the computational load by adopting a compact formulation and dynamically decreasing the number of active torque constrains. Moreover, for the case of a bimanual manipulation system, a suboptimal single-hand optimization algorithm is proposed and compared with that providing the optimal solution. Finally, a new algorithm for a valid initial-point evaluation is proposed. The effectiveness of the described methods has been tested in a simulation case study where the grasping forces of a humanoid torso equipped with two five-finger robotic hands are modified online to handle a load with a time-varying mass.\",\n \"Title: Preshaped visual grasp of unknown objects with a multi-fingered hand\\nYear: 2010\\n\\nAbstract: In this paper a method for fast visual grasp of unknown objects with a multi-fingered hand is presented. The algorithm is composed of an object surface reconstruction algorithm and a local grasp planner, evolving in parallel. The former uses an elastic reconstruction surface, whose dimensions are assigned initially by a preshaping process, and which shrinks toward the object until some parts of the surface intercept the object visual hull. The latter moves the fingertips on the current available reconstruction surface towards points which are optimal (in a local sense) with respect to a certain number of indices weighting both the grasp quality and the kinematic configuration of the hand. Experiments are presented, showing the effectiveness of the proposed algorithm.\",\n \"Title: Visual coordinated landing of a UAV on a mobile robot manipulator\\nYear: 2013\\n\\nAbstract: In this paper an image-based visual-servoing control law for the coordinated landing of a VToL UAV on an actuated landing platform is proposed. The landing platform is carried by a mobile manipulator composed of a mobile platform and a robotic arm. The UAV is endowed with a downward camera employed for the coordination of the landing manoeuvres. The presence of redundancy in the system at the task level, the intrinsic redundancy of the mobile manipulator, and the under-actuation of the UAV are explicitly addressed into the proposed control law. The effectiveness of the proposed approach is tested though simulations.\",\n \"Title: Online dextrous-hand grasping force optimization with dynamic torque constraints selection\\nYear: 2011\\n\\nAbstract: In this paper, a new algorithm for online grasping force optimization (GFO) of a dextrous robotic hand is presented. The GFO problem is cast in a convex optimization problem, considering also torque joint constraints. The proposed formulation allows to simplify the computational complexity of the problem by dynamically reducing the number of active torque constraints. Moreover, differently from other approaches, it does not require the evaluation of a new initial point at the beginning of each iteration. The effectiveness and the performance of the proposed method have been tested in a simulation case study where the hand manipulates a load with time-varying mass.\",\n \"Title: A mixed-initiative control system for an Aerial Service Vehicle supported by force feedback\\nYear: 2014\\n\\nAbstract: We present an approach to mixed initiative control for unmanned aerial vehicles (UAVs) where sliding autonomy is supported by mixed-initiative planning and haptic feedback. In the proposed framework, we assume that an autonomous system can plan and execute robotic tasks while a human operator can provide interventions when necessary receiving a force feedback. The haptic feedback is associated with the sensation about how the system is diverging from the planned operations. We tested the system at work in virtual and real environments considering simple navigation tasks. We compared the performance of human operators with or without the assistance of the force feedback. The collected results support the hypothesis that the proposed approach enables effective and intuitive mixed-initiative control.\",\n \"Title: Grasp the Possibilities: Anthropomorphic Grasp Synthesis Based on the Object Dynamic Properties\\nYear: 2015\\n\\nAbstract: The synthesis of optimal grasp configurations of heavy objects with anthropomorphic hands benefits from the explicit consideration of the object's dynamic properties. A new solution for the fast synthesis of anthropomorphic grasps that ensures the reduction of gravitational and inertial effects during the execution of manipulation tasks, as well as an equal distribution of the grasping forces among all fingers, is proposed in this article. The reduction of the computational complexity is achieved by considering only the regions of the object surface favoring the synthesis of minimal inertia grasps. Moreover, the hand and fingertip size, the hand kinematics, the object model uncertainty, and the surface curvature are all employed to further reduce the number of discrete grasping regions selected for the computation of the optimal grasp configurations with respect to a number of grasp quality indices. The effectiveness of the proposed method has been demonstrated with several case studies.\",\n \"Title: Exploiting redundancy in Cartesian impedance control of UAVs equipped with a robotic arm\\nYear: 2012\\n\\nAbstract: A Cartesian impedance control for UAVs equipped with a robotic arm is presented in this paper. A dynamic relationship between generalized external forces acting on the structure and the system motion, which is specified in terms of Cartesian space coordinates, is provided. Through a suitable choice of such variables and with respect to a given task, thanks to the added degrees of freedom given by the robot arm attached to the UAV, it is possible to exploit the redundancy of the system so as to perform some useful subtasks. The hovering control of a quadrotor, equipped with a 3-DOF robotic arm and subject to contact forces and external disturbances acting on some points of the whole structure, is tested in a simulated case study.\",\n \"Title: Wall inspection control of a VTOL unmanned aerial vehicle based on a stereo optical flow\\nYear: 2012\\n\\nAbstract: An autonomous wall inspection control based on a stereo optical flow, suitable for unmanned aerial vehicles endowed with a stereo vision system, is proposed in this paper. The inspection task consists of simultaneously controlling the inspection velocity along the surface, the relative yaw angle between the vehicle and the observed plane, as well as the orthogonal distance. A virtual spherical camera is considered at the center of gravity of the vehicle. Then, a stereo optical flow, as if it had been acquired by the virtual camera, is generated from the visual data provided by the stereo vision system. The 3D visual measurements are also employed to estimate the relative position and orientation of the observed plane. Hence, the absolute vehicle velocity is estimated by using a robust translational average optical flow by integrating the total stereo flow. Finally, an inspection control and a hovering control are proposed. The effectiveness of the described approach has been demonstrated with a dynamic simulation in an environment composed of two adjacent walls.\",\n \"Title: Fast incremental clustering and representation of a 3D point cloud sequence with planar regions\\nYear: 2012\\n\\nAbstract: An incremental clustering technique to partition 3D point clouds into planar regions is presented in this paper. The algorithm works in real-time on unknown and noisy data, without any initial assumption. An iterative cluster growing technique is proposed in order to correctly classify a flow of 3D points and to merge close regions. The computational efficiency of the approach is achieved by using an Incremental Principal Component Analysis (IPCA) technique, and with the adoption of a compact geometrical representation based on the concave-hull computation of each cluster. This solution adds a more realistic representation of the observed environment and reduces the number of points needed to identify the cluster shape. The effectiveness of the proposed algorithm has been validated with both synthetic and real data sets.\",\n \"Title: Nonlinear Visual Control of Unmanned Aerial Vehicles in GPS-Denied Environments\\nYear: 2015\\n\\nAbstract: In this paper, we propose a nonlinear controller that stabilizes unmanned aerial vehicles in GPS-denied environments with respect to visual targets by using only onboard sensing. The translational velocity of the vehicle is estimated online with a nonlinear observer, which exploits spherical visual features as the main source of information. With the proposed solution, only four visual features have shown to be enough for the observer to operate in a real scenario. In addition, the observer is computationally light with constant numerical complexity, involving small-dimension matrices. The observer output is then exploited in a nonlinear controller designed with an integral backstepping approach, thus yielding a novel robust control system. By means of Lyapunov analysis, the stability of the closed-loop system is proved. Extensive simulation and experimental tests with a quadrotor are carried out to verify the validity and robustness of the proposed approach. The control system runs fully onboard on a standard processor, and only a low-cost sensing suite is employed. Tracking of a target whose speed exceeds 2 $mathrm{m/s}$ is also considered in the real-hardware experiments.\",\n \"Title: Aerial Manipulation: A Literature Review.\\nYear: 2018\\n\\nAbstract: Aerial manipulation aims at combining the versatility and the agility of some aerial platforms with the manipulation capabilities of robotic arms. This letter tries to collect the results reached by the research community so far within the field of aerial manipulation, especially from the technological and control point of view. A brief literature review of general aerial robotics and space manipu...\",\n \"Title: Passivity-based control of VToL UAVs with a momentum-based estimator of external wrench and unmodeled dynamics\\nYear: 2015\\n\\nAbstract: A passivity-based control of Vertical Take-off and Landing (VToL) Unmanned Aerial Vehicles (UAVs) is presented in this paper. An estimator of unmodeled dynamics and external wrench (forces plus moments) acting on the aerial vehicle and based on the momentum of the system is employed to compensate such disturbances effects. This arrangement allows VToL UAVs to perform hovering, tracking and aerial manipulation tasks in unstructured environments. A rigorous stability proof is provided under certain assumptions. Experiments are presented to evaluate the performance of the proposed control design. Passivity-based framework is employed within a classical control scheme for UAVs.Control of angular dynamics does not rely upon exact model cancellation.Estimation is directly fed back to the passivity-based controller.Theoretical proofs and experiments are presented to validate the approach.\",\n \"Title: Tracking Fractures of Deformable Objects in Real-Time with an RGB-D Sensor\\nYear: 2015\\n\\nAbstract: This paper introduces a method able to track in real-time a 3D elastic deformable objects which undergo fractures, using the point cloud data provided by an RGB-D sensor. Our framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered by non-rigidly fitting the mesh, based on the Finite Element Method to physically model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. Fractures are handled by processing the stress tensors computed on the mesh of the FEM model, in order to detect fracturable nodes. Local remeshing around fracturable nodes is then performed to propagate the fracture. The real-time performance of the system is demonstrated on real data involving various deformations and fractures.\",\n \"Title: Autonomous landing of rotary-wing aerial vehicles by image-based visual servoing in GPS-denied environments\\nYear: 2015\\n\\nAbstract: In this paper we propose a new control method for quadrotor autonomous landing on a visual target without linear velocity measurements. Only onboard sensing is exploited, such that only the images of the landing pad from a down-looking camera, along with data from an Inertial Measurement Unit's gyro, are used. The control system consists of an image-based nonlinear observer that estimates online the linear velocity of the vehicle and a backstepping image-based controller that generates attitude, and thrust setpoints to the quadrotor autopilot. Both observer and controller share the same feedback information: spherical visual features. Therefore no further image elaboration is needed for the estimation. This, along with the fact that only simple computations on low- and constant-dimension arrays are involved, makes the proposed solution computationally cheap. Real-hardware experiments on a quadrotor are carried out to verify the validity of the proposed control system.\",\n \"Title: Mixed-Initiative Planning and Execution for Multiple Drones in Search and Rescue Missions.\\nYear: 2015\\n\\nAbstract: We present a mixed-initiative planning and execution system for human multi-drones interaction during search and rescue missions. The proposed system should allow a single operator to supervise and orchestrate the operations of a set of UAVs by means of a natural multimodal communication. In particular, we consider the task of searching for missing persons in a real-world alpine scenario. In this context, we assume that the human operator is an alpine rescuer, involved in the scene and co-located with the drones, hence not fully dedicated to the robotic platforms, but only able to provide sparse and sketchy interventions. This scenario requires a framework that supports adjustable autonomy, from explicit teleoperation to a complete autonomy, and an effective and natural mixed-initiative interaction between the human and the robotic team. In this paper, we illustrate the domain and the overall framework discussing the system at work in a simulated case study.\",\n \"Title: Multimodal Interaction with Multiple Co-located Drones in Search and Rescue Missions.\\nYear: 2016\\n\\nAbstract: We present a multimodal interaction framework suitable for a human rescuer that operates in proximity with a set of co-located drones during search missions. This work is framed in the context of the SHERPA project whose goal is to develop a mixed ground and aerial robotic platform to support search and rescue activities in a real-world alpine scenario. Differently from typical human-drone interaction settings, here the operator is not fully dedicated to the drones, but involved in search and rescue tasks, hence only able to provide sparse, incomplete, although high-value, instructions to the robots. This operative scenario requires a human-interaction framework that supports multimodal communication along with an effective and natural mixed-initiative interaction between the human and the robots. In this work, we illustrate the domain and the proposed multimodal interaction framework discussing the system at work in a simulated case study.\",\n \"Title: Design, Implementation and Experiments of a Robust Passivity-based Controller for a Rolling-balancing System.\\nYear: 2016\\n\\nAbstract: In this paper, we present the design of a robust interconnection and damping assignment controller for a rolling-balancing system known as the disk-on-disk. The underactuation feature of this system hampers the control design, and since we consider matched disturbances, the problem becomes even more challenging. To overcome this difficulty, we propose to design first a controller to stabilize the desired equilibrium of the case where the disturbance is not present, and then we robustify this controller by adding a nonlinear PID outer loop that compensates the disturbance. Finally, we evaluate the practical applicability of the control design by implementing the controllers on a real hardware for the disk-on-disk system.\",\n \"Title: An Optimal Trajectory Planner for a Robotic Batting Task: The Table Tennis Example.\\nYear: 2016\\n\\nAbstract: This paper presents an optimal trajectory planner for a robotic batting task . The specific case of a table tennis game performed by a robot is considered. Given an estimation of the trajectory of the ball during the free flight, the method addresses the determination of the paddle configuration (pose and velocity) to return the ball at a desired position with a desired spin. The implemented algorithm takes into account the hybrid dynamic model of the ball in free flight as well as the state transition at the impact (the reset map). An optimal trajectory that minimizes the acceleration functional is generated for the paddle to reach the desired impact position, velocity and orientation. Simulations of different case studies further bolster the approach along with a comparison with state-of-the-art methods.\",\n \"Title: Implicit Robot Selection For Human Multi-Robot Interaction In Search And Rescue Missions\\nYear: 2016\\n\\nAbstract: We present a system suitable for human multirobot interaction that supports the operator in the robot selection process. The proposed framework allows a human to issue commands to a robotic team without an explicit robot selection in so enabling a fluent interaction. This work is framed in the operative context of the SHERPA project [1], which proposes the deployment of a robotic platform for Search & Rescue in an alpine scenario and assumes the presence of a human rescuer that can orchestrate the robots operations with multimodal commands. In this context, implicit robot selection is mainly motivated by fast communication and the difficulties to distinguish different robots of similar shape in a hazardous environment and in adverse weather conditions. In the proposed approach, each robot of the team can evaluate the probability to be referred in an incomplete command, considering its actual capabilities along with geometrical and contextual information. We describe the overall system architecture focusing on the human intention recognition process. The proposed framework is trained and evaluated in a simulated case study.\",\n \"Title: Teleoperation of the SCHUNK S5FH under-actuated anthropomorphic hand using human hand motion tracking.\\nYear: 2017\\n\\nAbstract: This paper describes the development of a remote handling control of an anthropomorphic robotic hand, the SCHUNK S5FH, using the human hand as master by measuring its motion with OptiTrack Technology. The goal of this work is to enhance manipulation studies on the human hand and to instantly transfer those studies on robotic hands. A preliminary study on methods and devices used for fingers tracking led to the choice of a simplified kinematic model of the human hand on the basis of the available motion tracking system. Using the same criteria, the analysis of protocols for markers allocation led to define the number and a method for their arrangement on the fingers and palm. In order to overcome the limitation of the Motion Capture System, a method for identification and labeling has been developed according to their anatomical arrangement. Afterwards, the tracking is performed using the constraints between marker positions on the kinematic chain of the hand and a dynamic labeling algorithm robust with respect to noise, outliers and loss of markers. The validation is performed using the right hand of different subjects and considering different tasks involving flexion/extension and abduction/adduction of fingers and thumb opposition. For testing and validation, preliminary studies on synergies for manipulation tasks such as screwing a cup, has been conducted on the human hand and transferred on the robotic hand.\",\n \"Title: Tracking elastic deformable objects with an RGB-D sensor for a pizza chef robot.\\nYear: 2017\\n\\nAbstract: This paper presents a method for tracking a 3D textureless object which undergoes elastic deformations, using the point cloud data provided by an RGB-D sensor and in real-time. This solution is expected to be useful for enhanced manipulation of humanoid robotic systems, especially in the case of pizza dough to be ideally manipulated by a pizza chef robot. Our tracking framework relies on a prior visual segmentation of the object in the image. The segmented point cloud is registered first in a rigid manner and then by non-rigidly fitting the mesh, based on the Finite Element Method to model elasticity, and on geometrical point-to-point correspondences to compute external forces exerted on the mesh. The system has been evaluated on synthetic and real data, and by integrating it into manipulation experiments on the RoDyMan1 1\\n http://www.rodyman.eu/. The research leading to these results has been supported by the RoDyMan project, which has received funding from the European Research Council(FP7 IDEAS) under Advanced Grant agreement number 320992. The authors are solely responsible for its content. It does not represent the opinion of the European Community and the Community is not responsible for any use that might be made of the information contained therein.humanoid robotic platform.\",\n \"Title: Orbital stabilization of a VToL UAV for landing on oscillating platforms\\nYear: 2016\\n\\nAbstract: This paper presents preliminary theoretical results about asymptotic orbital stabilization of an aerial vehicle for landing on a periodic oscillating platform. A feedback controller firstly stabilizes a chosen set of virtual geometric constraints. This pushes the dynamics of the aerial vehicle to reach a limit cycle, that is in turn the periodic motion of the landing platform to track. Then, a linear periodic system is considered around the vicinity of the orbit, and it is stabilized through a modified LQR design. Mathematical and theoretical frameworks are presented along with case studies that are critically discussed.\",\n \"Title: The Effect of Shapes in Input-State Linearization for Stabilization of Nonprehensile Planar Rolling Dynamic Manipulation.\\nYear: 2016\\n\\nAbstract: A control framework for nonprehensile planar rolling dynamic manipulation is derived in this letter. By rotating around the center of mass, the manipulator moves a part without grasping it but exploiting its dynamics. Given some assumptions on the shapes of both the object and the manipulator, a state transformation is found rendering the state-space system in a chain of integrators form without i...\",\n \"Title: Vision-based and IMU-aided scale factor-free linear velocity estimator.\\nYear: 2017\\n\\nAbstract: This paper presents a new linear velocity estimator based on the unscented Kalman filter and making use of image information aided with inertial measurements. The proposed technique is independent of the scale factor in case of planar observed scene and does not require a priori knowledge of the scene. Image moments of virtual objects, i.e. sets of classical image features such as corners collected online, are employed as the sole correcting information to be fed back to the estimator. Experimental results performed with a quadrotor equipped with a fisheye camera highlight the potential of the proposed approach.\",\n \"Title: Passivity-Based Control for a Rolling-Balancing System: The Nonprehensile Disk-on-Disk.\\nYear: 2017\\n\\nAbstract: In this brief, we propose a passivity-based control design for a rolling-balancing system called the disk-on-disk (DoD). The stabilization of the desired equilibrium is obtained via energy shaping and damping injection. The DoD is an underactuated mechanical system composed of two disks arranged one on top of the other. The top disk, which we call the object, is free to roll without slipping on the lower disk, which we call the hand. The hand is actuated by a controlled torque, while the object is unactuated. The control objective is to balance the object at the upright position and drive the hand to a desired angle. We design an energy shaping controller without solving the partial differential equations, which rise from the matching equation. We assess the performance of the controller by both simulations and experiment results, which also verify the practical applicability of the design approach.\",\n \"Title: A robust multimodal fusion framework for command interpretation in human-robot cooperation\\nYear: 2017\\n\\nAbstract: We present a novel multimodal interaction framework supporting robust human-robot communication. We consider a scenario where a human operator can exploit multiple communication channels to interact with one or more robots in order to accomplish shared tasks. Moreover, we assume that the human is not fully dedicated to the robot control, but also involved in other activities, hence only able to interact with the robotic system in a sparse and incomplete manner. In this context, several human or environmental factors could cause errors, noise and wrong interpretations of the commands. The main goal of this work is to improve the robustness of human-robot interaction systems in similar situations. In particular, we propose a multimodal fusion method based on the following steps: for each communication channel, unimodal classifiers are firstly deployed in order to generate unimodal interpretations of the human inputs; the unimodal outcomes are then grouped into different multimodal recognition lines, each representing a possible interpretation of a sequence of multimodal inputs; these lines are finally assessed in order to recognize the human commands. We discuss the system at work in a case study in which a human rescuer interacts with a team of flying robots during Search & Rescue missions. In this scenario, we present and discuss real world experiments to demonstrate the effectiveness of the proposed framework.\",\n \"Title: Control of redundant robot arms with null-space compliance and singularity-free orientation representation.\\nYear: 2018\\n\\nAbstract: This paper tackles the problem of controlling the position and orientation, expressed in a singularity-free representation form, of the end-effector of a redundant robot, while addressing an active compliant behaviour within the null-space. The manuscript extends the work in Sadeghian et al. (2014) by explicitly addressing the orientation part. In order to successfully accomplish the task, a dynamic controller is designed without need of any exteroceptive sensors information. A rigorous stability analysis is provided to confirm the developed theory. Experiments are finally carried out to bolster the performance of the proposed approach.\",\n \"Title: Nonprehensile Manipulation of an Underactuated Mechanical System With Second-Order Nonholonomic Constraints: The Robotic Hula-Hoop.\\nYear: 2018\\n\\nAbstract: A mechanical system consisting of a hoop and a pole is considered, for which the corresponding dynamic model represents an underactuated system subject to second-order nonholonomic constraints. The pursued goal is to simultaneously track a trajectory in the unactuated coordinates and to stabilize the actuated ones. For the model under consideration, the well-known noncollocated partial feedback li...\",\n \"Title: Introduction To The Special Issue On Aerial Manipulation\\nYear: 2018\\n\\nAbstract: The papers in this special section focus on aerial manipulation which is intended as grasping, positioning, assembling and disassembling of mechanical parts, measurement instruments and any other kind of objects, performed by a flying robot equipped with arms and grippers. Aerial manipulators can be helpful in those industrial and service applications that are considered very dangerous for a human operator. For instance, think of tasks like the inspection of a bridge, the inspection and the fixing-up of high-voltage electric lines, the repairing of rotor blades and so on. These tasks are both very unsafe and expensive because they require the performance of professional climbers and/or specialists in the field. A drone with manipulation capabilities can instead assist the human operator in these jobs or, at least, in the most hazardous and critical situations. As a matter of fact, such devices can indeed operate in dangerous tasks like reaching the bottom of the deck of a bridge or the highest places of a plant or a building; they can avoid dangerous work at height; aerial platforms can increase the total number of inspections of a plant, monitoring the wear of the components. Without doubts, aerial manipulation will improve the quality of the job of many workers.\",\n \"Title: Nonprehensile Dynamic Manipulation: A Survey.\\nYear: 2018\\n\\nAbstract: Nonprehensile dynamic manipulation can be reasonably considered as the most complex manipulation task. It might be argued that such a task is still rather far from being fully solved and applied in robotics. This survey tries to collect the results reached so far by the research community about planning and control in the nonprehensile dynamic manipulation domain. A discussion about current open i...\",\n \"Title: Image-Based Visual-Impedance Control of a Dual-Arm Aerial Manipulator.\\nYear: 2018\\n\\nAbstract: Three new image-based visual-impedance control laws are proposed in this letter allowing physical interaction of a dual-arm unmanned aerial manipulator equipped with a camera and a force/torque sensor. Namely, two first-order impedance behaviors are designed based on the transpose and the inverse of the system Jacobian matrix, respectively, while a second-order impedance behavior is carried out as...\",\n \"Title: Nonprehensile Manipulation of Deformable Objects: Achievements and Perspectives from the Robotic Dynamic Manipulation Project.\\nYear: 2018\\n\\nAbstract: The goal of this article is to disseminate the planning and control strategies for robotic nonprehensile manipulation results achieved so far with the Robotic Dynamic Manipulation (RoDyMan) project. The goal of the project is to advance the state of the art of nonprehensile dynamic manipulation of rigid and deformable objects to enhance the possibility of employing robots in anthropic environments. RoDyMan projectu0027s final demonstration will be acting as an autonomous pizza maker. This article highlights the lessons learned and paves the way toward critical discussions and future research.\",\n \"Title: Capturing Deformations of Interacting Non-rigid Objects Using RGB-D Data\\nYear: 2018\\n\\nAbstract: This paper presents a method for tracking multiple interacting deformable objects undergoing rigid motions, elastic deformations and contacts, using image and point cloud data provided by an RGB-D sensor. A joint registration frame-work is proposed, based on physical Finite Element Method (FEM) elastic and interaction models. It first relies on a visual segmentation of the considered objects in the RGB images. The different segmented point clouds are then processed to estimate rigid transformations with on an ICP algorithm, and to determine geometrical point-to-point correspondences with the meshes. External forces resulting from these correspondences and between the current and the rigidly transformed mesh can then be derived. It provides both non-rigid and rigid data cues. A classical collision detection and response model is also integrated, giving contact forces between the objects. The deformations of the objects are estimated by solving a dynamic system balancing these external and contact forces with the internal or regularization forces computed through the FEM elastic model. This approach has been here tested on different scenarios involving two or three interacting deformable objects of various shapes, with promising results.\",\n \"Title: A control architecture for multiple drones operated via multimodal interaction in search & rescue mission\\nYear: 2016\\n\\nAbstract: An architecture suitable for the control of multiple unmanned aerial vehicles deployed in Search & Rescue missions is presented in this paper. In the proposed system, a single colocated human operator is able to coordinate the actions of a set of robots in order to retrieve relevant information of the environment. This work is framed in the context of the SHERPA project whose goal is to develop a mixed ground and aerial robotic platform to support search and rescue activities in alpine scenario. Differently from typical human-drone interaction settings, here the operator is not fully dedicated to the drones, but involved in search and rescue tasks, hence only able to provide sparse and incomplete instructions to the robots. In this work, the domain, the interaction framework and the executive system for the autonomous action execution are discussed. The overall system has been tested in a real world mission with two drones equipped with on-board cameras.\",\n \"Title: Attentional Multimodal Interface For Multidrone Search In The Alps\\nYear: 2016\\n\\nAbstract: We present a multimodal attentional interface suitable for a human operator that monitors and controls the activities of a team of drones during search and rescue missions. We consider a scenario where the operator is a component of the rescue team, hence not fully dedicated to the robots, but only able to interact with them with sparse and incomplete commands. In this context, an adaptive interface is needed to support the user situation awareness and to enable an effective interaction with the drones. In this work, we propose a multimodal attention-based interface designed for this domain. This framework is to filter the information flow towards the operator selecting and adapting the communication mode according to the context and the human state. We illustrate the features of the adaptive system along with an initial assessment in a simulated scenario.\",\n \"Title: On the Experiments About the Nonprehensile Reconfiguration of a Rolling Sphere on a Plate\\nYear: 2018\\n\\nAbstract: A method to reconfigure in a nonprehensile way the pose (position and orientation) of a sphere rolling on a plate is proposed in this letter. The nonholonomic nature of the task is first solved at a planning level, where a geometric technique is employed to derive a Cartesian path to steer the sphere towards the arbitrarily desired pose. Then, an integral passivity-based control is designed to track the planned trajectory. The port-Hamiltonian formalism is employed to model the whole dynamics. Two approaches to move the plate are addressed in this paper, showing that only one of them allows the full controllability of the system. A humanoid-like robot is employed to bolster the proposed method experimentally.\",\n \"Title: Control of the TORA System through the IDA-PBC without Explicit Solution of Matching Equations\\nYear: 2019\\n\\nAbstract: This paper presents the control of a translational oscillator with a rotational actuator (TORA) system, in full gravity, through the interconnection and damping assignment passivity-based control (IDA-PBC). The sought goal is to control the underactuated TORA system while reducing the complexity in solving the partial differential equations coming out from the so-called matching equations, which arise from the IDA-PBC. The performance of the designed controller is illustrated through numerical simulations.\",\n \"Title: Control of Nonprehensile Planar Rolling Manipulation: A Passivity-Based Approach.\\nYear: 2019\\n\\nAbstract: This paper presents a new procedure to design a control law using the classical interconnection and damping assignment technique within the passivity-based port-Hamiltonian framework. The sought goal is to reduce the complexity of solving the so-called matching equations. The proposed approach is applied to two case studies of planar rolling nonprehensile manipulation, namely, the ball-and-beam an...\",\n \"Title: 6D Pose Task Trajectory Tracking for a Class of 3D Aerial Manipulator From Differential Flatness\\nYear: 2019\\n\\nAbstract: In this paper, the dynamics and control of a novel class of aerial manipulator for the purpose of end effector full pose trajectory tracking are investigated. The 6D pose of the end effector is set as a part of the flat output, from which the conditions that the system has the proposed flat output is obtained. The control law for the end effector tracking purpose is designed. The core part of the controller is an almost global controller in the configuration space of the system. From the transformation between the state space and the output space, the tracking control of the end effector in SE (3) is also achieved. The stability of the controlled system is analyzed. A numerical example is presented to demonstrate the theoretical analysis.\",\n \"Title: A Novel Articulated Rover For Industrial Pipes Inspection Tasks\\nYear: 2021\\n\\nAbstract: Inspection and maintenance of industrial pipes using robots represent an emerging application in Oil & Gas and refinery facilities for Nondestructive Tests (NDT). In this work, we present the design and development of a novel articulated mobile robot able to safely navigate over straight and curved pipes for inspection tasks. This rover is meant to be the base of the hybrid aerial-ground platform of the HYFLIERS project that aims to develop novel solutions to perform inspection measurements with reduced exposure to risks and costs. Thanks to the multiple degrees of freedom and onboard sensors, the rover proposed in this paper can stabilize and navigate on a pipe across welding and over curves. After discussed the mechanical design of the rover, we demonstrate its effectiveness in the localization and navigation of curved pipes.\",\n \"Title: Energy pumping-and-damping for gait robustification of underactuated planar biped robots within the hybrid zero dynamics framework\\nYear: 2021\\n\\nAbstract: This paper addresses the robust gait control for planar and passive biped robots using approaches based on energy properties. Energy pumping-and-damping passivity-based control is used to increase the robustness against uncertainties on the initial conditions of the passive gait exhibited by planar biped robots. The stability analysis is carried out by exploiting the system’s passivity and the hyb...\",\n \"Title: Robust Visual Localization of a UAV Over a Pipe-Rack Based on the Lie Group SE(3)\\nYear: 2022\\n\\nAbstract: Visual inspection and maintenance ofindustrialpipes using robots represent an emerging application in Oil & Gas and refinery facilities. In this domain, we present a pose tracking system based on a single camera sensor to localize an unmanned aerial vehicle operating over a pipe-rack to carry out inspection activities. We propose a unified framework based on the Lie group SE(3) which allows the simultaneous estimation of the pose of the UAV along with some parameters of the pipe-rack model. Numerical simulations have been performed to demonstrate the effectiveness of the proposed approach.\",\n \"Title: A hardware-in-the-loop simulator for physical human-aerial manipulator cooperation\\nYear: 2021\\n\\nAbstract: A hardware-in-the-loop simulator for human cooperation with an aerial manipulator is presented in this paper. The simulator provides the user with realistic haptic feedback proper of a human-aerial manipulator interaction activity. The forces exchanged between the hardware interface and the human/environment are measured and supplied to a dynamically simulated aerial manipulator. In turn, the simulated aerial platform feeds back its position to the hardware allowing the human to feel and evaluate the interaction effects. Besides human-aerial manipulator cooperation, the simulator lends itself to developing and testing autonomous control strategies in aerial manipulation. Therefore, the effectiveness of the proposed system is evaluated along with two case studies: a collaborative task where the human operator attaches a tool to the robot end-effector and an autonomous bird diverter installation task.\",\n \"Title: Transfer from existing flight control of under-actuated aerial vehicles to interaction control of aerial slung load systems\\nYear: 2021\\n\\nAbstract: This paper investigates a framework to design the interaction control of the aerial slung load system which is composed of an underactuated aerial vehicle, a cable, and a load. Instead of designing new controller for the system, we show that the interaction control of the system can be totally transferred from the controllers for under-actuated aerial systems. Selecting the differentially flat output as the configuration, the equation of motion of the two systems is written in the same format. The flight controller of the under-actuated aerial vehicle is thus migrated to control the aerial slung load system. We adopt the admittance filter to generate the compliant trajectory of the load under external interaction force. Furthermore, from the boundedness of the vehicle attitude tracking error and the external force estimation error, the convergence of the entire system is proved. Based on this theoretical foundation, an example interaction controller for the aerial slung load is derived from an existing flight controller directly, by including an external force estimator. The example controller is demonstrated in the numerical simulation.\",\n \"Title: Visual control through narrow passages for an omnidirectional wheeled robot\\nYear: 2022\\n\\nAbstract: Robotic systems are gradually replacing human intervention in dangerous facilities to improve human safety and prevent risky situations. In this domain, our work addresses the problem of autonomous crossing narrow passages in a semi-structured (i.e., partially-known) environment. In particular, we focus on the CERN’s Super Proton Synchrotron particle accelerator, where a mobile robot platform is equipped with a lightweight arm to perform measurements, inspection, and maintenance operations. The proposed approach leverages an image-based visual servoing strategy that exploits computer vision to detect and track known geometries defining narrow passage gates. The effectiveness of the proposed approach has been demonstrated in a realistic mock-up.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":80,"string":"80"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13346,"string":"13,346"}}},{"rowIdx":13347,"cells":{"question_id":{"kind":"string","value":"Li Sun"},"question":{"kind":"string","value":"Generate an abstract for the title \"Recognizing architecture styles by hierarchical sparse coding of blocklets.\" using the following items: architecture, blocklets, recognition, hierarchical sparse coding, discriminative blocklets"},"answer":{"kind":"string","value":"In this work, we propose a novel architecture style recognition model by introducing blocklets that capture the morphological characteristics of buildings. First, we decompose a building image into a collection of blocks, each representing a basic architecture component such as a stone pillar. To exploit the spatial correlations among blocks, we obtain locklets by extracting spatially adjacent blocks, and further formulate architecture style recognition as matching between blocklets extracted from different buildings. Toward an efficient blocklet-to-blocklet matching, a hierarchical sparse coding algorithm is proposed to represent each blocklet by a linear combination of basis blocklets. On the other hand, toward an effective matching process, an LDA [25,1]-like scheme is adopted to select the blocklets with high discrimination. Finally, we carry out architecture style recognition based on the selected highly discriminative blocklets. Experimental results on our own compiled data set demonstrate that the proposed approach outperforms several state-of-the-art place/building recognition models."},"correct_answer":{"kind":"string","value":"In this work, we propose a novel architecture style recognition model by introducing blocklets that capture the morphological characteristics of buildings. First, we decompose a building image into a collection of blocks, each representing a basic architecture component such as a stone pillar. To exploit the spatial correlations among blocks, we obtain locklets by extracting spatially adjacent blocks, and further formulate architecture style recognition as matching between blocklets extracted from different buildings. Toward an efficient blocklet-to-blocklet matching, a hierarchical sparse coding algorithm is proposed to represent each blocklet by a linear combination of basis blocklets. On the other hand, toward an effective matching process, an LDA [25,1]-like scheme is adopted to select the blocklets with high discrimination. Finally, we carry out architecture style recognition based on the selected highly discriminative blocklets. Experimental results on our own compiled data set demonstrate that the proposed approach outperforms several state-of-the-art place/building recognition models."},"documents":{"kind":"list like","value":["Title: Reciprocally Benefited Spectrum Access Scheme With Joint Power and Subcarrier Allocation in a Software-Defined Network.\nYear: 2015\n\nAbstract: Aiming at realizing ubiquitous spectrum access and improving the spectrum efficiency in a software-defined network, in this paper, we adopt the concept of cognitive radio and propose a joint subcarrier and power allocation (JSPA) scheme for reciprocally benefited spectrum access with secondary users (SUs) cooperating with primary users (PUs). In our proposed JSPA scheme, SUs adopt the decode-and-f...","Title: Real time gaze estimation with a consumer depth camera\nYear: 2015\n\nAbstract: Simple-setup real-time gaze estimation system using only a consumer depth camera.3D model based gaze estimation method allowing free head movement.Iris center localization method able to handle relatively low-quality eye images.Simple system calibration easy to be carried out for nonprofessional users. Existing eye-gaze-tracking systems typically require multiple infrared (IR) lights and high-quality cameras to achieve good performance and robustness against head movement. This requirement limits the systems' potential for broader applications. In this paper, we present a low-cost, non-intrusive, simple-setup gaze estimation system that can estimate the gaze direction under free head movement. In particular, the proposed system only uses a consumer depth camera (Kinect sensor) positioned at a distance from the subject. We develop a simple procedure to calibrate the geometric relationship between the screen and the camera, and subject-specific parameters. A parameterized iris model is then used to locate the center of the iris for gaze feature extraction, which can handle low-quality eye images. Finally, the gaze direction is determined based on a 3D geometric eye model, where the head movement and deviation of the visual axis from the optical axis are taken into consideration. Experimental results indicate that the system can estimate gaze with an accuracy of 1.4-2.7¿ and is robust against large head movements. Two real-time human-computer interaction (HCI) applications are presented to demonstrate the potential of the proposed system for wide applications.","Title: Background modeling and its evaluation for complex scenes\nYear: 2015\n\nAbstract: We present a new approach for modeling background in complex scenes that contain unpredicted motions caused e.g. by wind over water surface, in tree branches, or over the grass. The background model of each pixel is defined based on the observation of its spatial neighborhood in a recent history, and includes up to K 1$K \\ge 1$ modes, which defines the frequently appeared patterns at the given pixel position in the color space, ranked in decreasing order of occurrence frequency. Foreground regions can then be detected by comparing the intensity of an observed pixel to the high frequency modes of its background model. Experiments show that our spatial-temporal background model is superior to traditional related algorithms in cases for which a pixel encounters modes that are frequent in the spatial neighborhood without being frequent enough in the actual pixel position. As an additional contribution, our paper also proposes an original assessment method, which has the advantage of avoiding the use of costly handmade ground truth sequences of foreground objects silhouettes.","Title: Fountain-Coding Aided Strategy for Secure Cooperative Transmission in Industrial Wireless Sensor Networks.\nYear: 2016\n\nAbstract: Cooperative relaying communications is an efficient paradigm for end-to-end data delivery in industrial wireless sensor networks. However, due to the broadcast nature of radio propagation, it is challenging to guarantee the secrecy of cooperative transmissions under eavesdropping attacks. To deal with this issue, a fountain-coding aided relaying scheme is proposed in this paper, for which all the ...","Title: Noncontact Vital Sign Detection based on Stepwise Atomic Norm Minimization\nYear: 2015\n\nAbstract: Noncontact techniques for detecting vital signs have attracted great interest due to the benefits shown in medical monitoring and military applications. A rapid remote evaluation on physiological signal frequencies is needed in search and rescue operations as well as intensive care. However, the presence of respiration harmonics causes aliasing problems to heart-rate estimation, especially when th...","Title: Redundant-coded radial and neighbor star pattern identification algorithm\nYear: 2015\n\nAbstract: Aimed at solving the lost-in-space (LIS) problem, a robust star pattern identification algorithm is presented. The neighbor star pattern is introduced to increase separating ability and stabilization of star patterns and reduce the effects of magnitude noise. Redundant coding for radial and neighbor star patterns is proposed to more effectively remove the effects of position noise. Binary bit strings are used for storing the redundant code to reduce the size of the on-board database. A similar score measurement is proposed on the basis of shift and logical AND operations to quickly implement the star's initial match. The final match results are obtained using a strategy of searching for the longest matching chain. The algorithm is evaluated with synthesized and real star images. The identification rates of this algorithm are 97.98% with standard deviations of position noises of 1 pixel and 94.96% with standard deviations of magnitude noises of 0.646 Mv. Moreover, the identification rate is 77.12% when there are only four stars in the field of view (FOV). The algorithm obtains an average identification rate of 96.96% from real star images.","Title: Interference-controlled D2D routing aided by knowledge extraction at cellular infrastructure towards ubiquitous CPS\nYear: 2015\n\nAbstract: Device-to-device (D2D) networks underlaying cellular networks are widely recognized as one of the major approaches for ubiquitous information acquisition and exchange, which features the future cyber-physical systems (CPSs). In this paper, we propose the interference-controlled D2D routing designs underlaying cellular networks, i.e. sharing/reusing the cellular spectrum, to support multi-hop D2D transmissions and thus enhancing the flexibility of CPS. The unique feature and challenge for this task include threefolds. First, the huge density of device nodes in future cellular networks yields huge amount of information to process. Second, as device nodes in cellular networks do not maintain the routing table, the route selection via low-complexity knowledge-extraction approach over huge amount of information needs to be performed by the base station (BS). Third, the interference generated by reusing cellular spectrum needs to be thoroughly controlled. To address these issues, we in this work consider two D2D networking scenarios that allow D2D users to share the uplink and downlink spectrum of cellular networks, respectively. Our objective for routing is hop-count minimization such that the delay and power consumptions can be decreased. In particular, we propose a maximum rate towards destination (MR-D) routing algorithm for the scenario sharing uplink spectrum and a MR-D advanced (MR-DA) routing algorithm for the scenario sharing downlink spectrum, respectively. Both algorithms have low computational complexity and thus meaningful for practical systems. Furthermore, our routing designs can avoid the violation of tolerable interferences to cellular users as well as to fulfil the rate requirement of D2D services. Also conducted are abundant simulation evaluations to demonstrate the advantages of our proposed schemes as compared to the baseline schemes including the farthest neighbour routing and closest to destination routing scheme.","Title: A Vision System Based On Tof 3d Imaging Technology Applied To Robotic Citrus Harvesting\nYear: 2015\n\nAbstract: This study was conducted to develop a fast machine vision system based on TOF (time of flight) three-dimensional (3D) imaging technology for automatic citrus recognition and location. Supported algorithms were specifically developed and programmed for image acquisition and processing. An adaptive filter coupled between partial differential equations filter and shock filter was presented to remove noise and sharpen edges efficiently. Image analysis algorithms integrated both range and amplitude information to generate regions of interest and parameters that are characteristic or very likely to belong to spherical objects. The three-dimensional position of the fruit and radius are obtained after the recognition stages. The total classification results showed that approximately 81.8% were detected and false detection occurred only once. On the whole, the process of imaging, recognition and location consumes less than 50ms/fruit.","Title: Precoder-and-receiver design scheme for multi-user coordinated multi-point in LTE-A and fifth generation systems.\nYear: 2016\n\nAbstract: Coordinated multi-point (CoMP) techniques can be utilised in several wireless systems, such as LTE-A and fifth generation. However, inter-user interferences (IEIs) and intra-user interferences (IAIs) may degrade the quality of service in joint transmission (JT), CoMP systems. To suppress these interferences, the authors design an interference mitigation scheme via interference alignment (IA) and c...","Title: New optimisation model and fuzzy adaptive weighted genetic algorithm for hazardous material transportation\nYear: 2012\n\nAbstract: On the basis of analysing the unusual objectives of hazardous material transportation HMT, a new multi-objective optimisation model for hazardous material transportation MOM-HMT is established, which takes into account transportation risk, operation time, the number of sensitive population, risks fairness and multi-batch transportation simultaneously. Then a fuzzy adaptive weighted genetic algorithm FAWGA is set up to solve the MOM-HMT by designing priority-based encoding method, partial matching crossover, fuzzy logic control and adaptive weighted assignment mechanism. Finally, the model and algorithm are applied to a real case. The study results show the new model is feasible and the improved genetic algorithm is more effective than the standard genetic algorithm and the improved ant colony algorithm.","Title: Prediction based interference management and distributed trajectory regulation in amorphous cells\nYear: 2015\n\nAbstract: The amorphous cells have emerged as a new paradigm to meet the fast increasing wireless capacity and coverage demands. Compared with the traditional cellular networks with hexagon-based deployments, the amorphous cells support mobile base stations (MBS) to form dynamic cell topologies, which can adapt to the group-movement behaviors of network loads. These amorphous cells are required to be self-organized so as to facilitate distributed coordination between MBSs, whereby the operational costs can be effectively reduced. Moreover, the management of cochannel interferences needs to take MBSs??? movement into account, which is the new challenge not encountered in traditional cellular networks. In this paper, we propose a distributed trajectory regulation algorithm aiming at enhancing the reliability of communications for multiple mobile-host (MH) groups, while not violating the required travel time budgets. For this purpose, we jointly consider the prediction of channel conflicts across MBSs???, the channel collision costs, and cooperative channel allocation for trajectory control. Simulation evaluations show that our algorithm can well balance the reliability and travel time. The simulation results also demonstrate the reduction of failure rate for incoming calls compared with the conventional approach, especially when the network load is high.","Title: Accurate garment surface analysis using an active stereo robot head with application to dual-arm flattening\nYear: 2015\n\nAbstract: We present a visually guided, dual-arm, industrial robot system that is capable of autonomously flattening garments by means of a novel visual perception pipeline that fully interprets high-quality RGB-D images of a clothing scene based on an active stereo robot head. A segmented clothing range map is B-Spline smoothed prior to being parsed by means of shape and topology analysis into ‘wrinkle’ structures. The length, width and height of each wrinkle is used to quantify the topology of each wrinkle and thereby rank wrinkles by size such that a greedy algorithm can identify the largest wrinkle present. A flattening plan optimised for the largest detected wrinkle is formulated based on dual-arm manipulation. We report the validation of our autonomous flattening behaviour and observe that dual-arm flattening requires significantly fewer manipulation iterations than single-arm flattening. Our experimental results also reveal that the flattening process is heavily influenced by the quality of the RGB-D sensor: use of a custom off-the-shelf high-resolution stereo-based sensor system outperformed a commercial low-resolution kinect-like camera in terms of required flattening iterations.","Title: A Novel Data Mining Method on Falling Detection and Daily Activities Recognition\nYear: 2015\n\nAbstract: With the intensification of aging population, a growing number of elderly people have to live alone due to domestic and social reasons. Falling becomes one of the most crucial factors in threatening the elderly's lives, which is always difficult to be detected as it is instantaneous and easy to be confused with other motions, such as lying down. In this paper, a new method is proposed for accurate falling detection and activities recognition. It applies hierarchical classifiers to the time series data set including eleven activities of daily living (ADLs), collected by four wearable sensors. The new method combines two machine learning algorithms, performs concrete analysis on the original outcome and then obtains several scarcely-confused groups separately. The experiment indicates that the new method improves the accuracy of classification to a larger extent, reached to more than 90%. Furthermore, the matched algorithm for applying these classifiers, called Hierarchical Classifier Algorithm (HCA), is proposed as well.","Title: Cooperative jamming with untrusted SUs for secure communication of two-hop primary system\nYear: 2015\n\nAbstract: This paper investigates the problem of secure communications of the two-hop primary system with the cooperative jamming of the untrusted secondary system. The secondary system is untrusted for the primary system and willing to eavesdrop on the primary signal. In addition, the secondary system is also willing to provide friendly jamming to increase the secure rate of the primary system in reward for being allowed to share the licensed spectrum. Specifically, the cooperative communication is implemented into two slots which correspond to the transmission of the first and second hops of the primary system, respectively. In each slot, part of the slot is allocated for the primary information transmission. Simultaneously, a secondary user (SU) is selected to broadcast jamming signal to protect the secure communication of the primary users (PU) against the other untrusted SUs. Then, the remaining time of the slot is allocated for the secondary transmission. To maximize the transmission rate of the secondary system under the constraint of the target secure rate requirement of the primary system, we optimally select two jamming SUs and determine the time parameters in each slot. SUs' average transmit rate and the lower bound on PUs' secure outage probability are derived. Simulation results demonstrate the performance superiority of our developed strategy over conventional secure communication schemes in terms of PUs' secure outage probability and SUs' average transmission rate.","Title: Robust Precoder-And-Receiver Design For Interference Suppression And Channel Uncertainty Restraint In Multi-User Comp System\nYear: 2015\n\nAbstract: Inter-user interferences (IEIs) and intra-user interferences (IAIs) may degrade the quality-of-service in JT (joint transmission)-CoMP (coordinated multi-point) systems. Interference alignment (IA) with prefect channel state information (CSI) can efficiently mitigate these interferences. However, in realistic systems, the effect of IA is obviously decreased via channel uncertainty with channel estimation and quantization errors. In this case, we propose a novelly robust precoder-and-receiver design scheme with IA (NRIA) for interference suppression and channel uncertainty restraint. In the NRIA, we first utilize precoding method to suppress the IEIs to each user generated by the users' actually acquired channels. Second, the receiver of each user is devised to alleviate the impact of IAI and channel uncertainty. Unlike the existing MU-MIMO schemes which introduce the statistical or bounded information of the above errors, the NRIA is a local scheme for JT and contains the instantaneous information of channel uncertainty. The instantaneous information can be abstracted through installing and sending special transmit signals from base stations to users without exorbitant overhead. The NRIA doesn't include any iteration, moreover, it can suppress interference and improve robustness compared with just using statistical or bounded information of channel uncertainty.","Title: Statistical security model and power adaptation over wireless fading channels\nYear: 2015\n\nAbstract: Secrecy capacity is the widely-used metric to evaluate the capability of wireless channels in delivering messages with the assurance of perfect security as well as reliability. However, with the proliferation and diversification of wireless services, there have been urgent needs in fine-grained and decoupled security metrics towards future mobile communications. In this paper, we propose a statistical model to characterize the finegrained security level, while evaluating the secrecy independently from the reliability. Specifically, we model the data eavesdropping process by a queuing system, where the data arrival represents the information overheard by the eavesdropper. The departure process is modeled by a constant leaving rate, implying that the eavesdropped data will become useless after certain time. The eavesdropper has to accumulate sufficient amount of data for successful decipherment. We further define the novel statistical security metric via a queue-length bound and a bound-violation probability threshold. As long as the violation probability is below the specified threshold, the statistical security is guaranteed. This model can fit diverse services well by tuning corresponding parameters for the statistical security metric. Following the statistical security model, we formulate the security-driven power adaptation problem for throughput maximization over fading channels. Applying asymptotic queuing analyses and effective bandwidth theory, we solve the problem and obtain a set of power control schemes under diverse system parameters. Simulation evaluations are also presented to demonstrate the superiority of our scheme over the baseline schemes.","Title: Joint Secure Beamforming And User Selection For Multi-User Miso Systems With Confidential Messages\nYear: 2015\n\nAbstract: In this paper, we propose a joint secure beamforming and user selection (J-SBS) scheme to improve the secrecy sum rate in multi-user multiple-input-single-output (MISO) broadcast channels with confidential messages (BCC). The user selection mechanism can bring about multi-user diversity which may be also exploited by eavesdroppers in multi-user MISO sysytem. We show how the system secrecy sum rate under the semi-orthogonal user selection (SUS) algorithm will be limited if users collude with each other. To solve this problem, based on the prediction that selected users have mutual orthogonal beamformers, we characterize a new expression of the secrecy rate. By optimizing the secrecy rate we then derive a corresponding suboptimal secrecy beamformer for each user to reduce the interference and information leakage. Moreover, we apply SUS to select suitable beamformers matching with the prediction. Simulation results show the effectiveness of our proposed method.","Title: Information Security Enhancement With Actual Access Statuses Of Users In The Multi-User System\nYear: 2015\n\nAbstract: In the new generation wireless communication systems, when multiple users are served, information security among them should be considered to protect each user's privacy. In this case, physical layer security techniques can be adopted for this mutual confidence problem. Unlike other traditional physical layer security methods, the proposed scheme improves secrecy rate with the information of users' access statuses (i.e., being served or idle), and it is denoted as SRT-AS. In the SRT-AS, appropriate parameters expressing users' actual access statuses are introduced, and an adaptive transmitter and receiver design strategy is used to increase security. It can be found that no iterative process is included in the SRT-AS, moreover, performance analysis and simulation results illustrate that the SRT-AS is feasible for the multi-user system.","Title: Estimation Based Adaptive Acb Scheme For M2m Communications\nYear: 2015\n\nAbstract: It is a critical challenge to support massive access of devices in a short period in machine-to-machine (M2M) communications. In this paper, we propose a estimation based adaptive Access Class Barring (ACB) scheme to improve the scalability of M2M networks. First, we propose a simple estimation scheme to estimate the network loads. Then we obtain two functions which are the relationship of ACB's barring factor (the parameter of access probability) and network loads to maximize the system throughput. According to the estimation and the obtained functions, eNB changes ACB barring factor dynamically to adapt to the network load conditions. At the same time, we summarize the boundedness of the adaptive scheme. Finally, simulation results illustrate that our scheme can increase the system throughput and reduce access delay obviously.","Title: Enhancing Wireless Security Against Reactive Jamming Attacks: A Game-Theoretical Framework\nYear: 2015\n\nAbstract: Reactive jamming, which launches jamming attacks when the legitimate transmissions are detected, is one of the most serious security threats in wireless communications. In this paper, we investigate the wireless security issue in the presence of a reactive jammer from a game-theoretical perspective. Specifically, the legitimate user and jammer respectively aim at maximize and minimize the expected legitimate transmission rate, which is formulated as a zero-sum game. For the jammer, we consider the imperfection in detection and analyze the optimal jamming strategy by the joint optimization over detection time and jamming power. For the legitimate user, the transmit power is optimized by achieving the tradeoff between obtained transmission rate and the probability to be accurately detected and thus jammed by its adversary. The Nash equilibrium is characterized by the best-response playing between the legitimate user and reactive jammer. Finally, we present simulation results to verify the effectiveness of our proposed approach.","Title: Semisupervised Classification Of Sar Images By Maximum Margin Neural Networks Method\nYear: 2015\n\nAbstract: The proposed method is based on neural networks by modeling the data marginal distribution with the graph Laplacian built with both labeled and unlabeled samples, at the same time, optimizing neural networks layers in a single process, back-propagating the gradient of a Maximum Margin based objective function. Therefore, the proposed approach gives rise to an operational classifier, as opposed to previously presented semi-supervised scenarios. Results demonstrate the improved classification accuracy and scalability of this approach on SAR image classification problems.","Title: Multispectral Image Fusion Based On Laplacian Pyramid Decomposition With Immune Co-Evolutionary Optimization\nYear: 2015\n\nAbstract: In this paper, a new multispectral image fusion algorithm is proposed by considering the abundant directional information and complex high frequency of source images. In this algorithm, Laplacian pyramid (LP) is constructed to filter the source images to obtain initial fusion coefficients, then an evolution computation idea, immune co-evolutionary optimization algorithm, is introduced into the image fusion to optimize the fusion coefficients. The optimized fusion coefficients can make better fusion result. Simulation experiments of clearly demonstrate the superiority of this proposed algorithm by comparing with conventional wavelets systems: the information entropy (IE) values keep at a similar level, the average grads (AG) values are higher, the standard deviation (STD) values increases 1.2 averagely, and the time efficiency increases averagely about 51 %.","Title: Dt-Cwt-Based Improved Baq For Anti-Saturation Sar Raw Data Compression\nYear: 2015\n\nAbstract: In this paper, an anti-saturation raw data compressing algorithm for Synthetic Aperture Radar (SAR) based on Dual-Tree Complex Wavelet Transform (DT-CWT) and improved Block Adaptive quantization (BAQ) is proposed. The DT-CWT has approximate shift-invariant and good directional selectivity. The improved BAQ rebuild data keeps the saturation signal. We apply DT-CWT to fractional saturation SAR raw data. The result put into improved BAQ quantizer. Experiment shows this method has a high compression rate and Signal to Noise Ratio (SNR).","Title: EYEWATCHME- 3D hand and object tracking for inside out activity analysis\nYear: 2009\n\nAbstract: This paper investigates the \"inside-out\" recognition of everyday manipulation tasks using a gaze-directed camera, which is a camera that actively directs at the visual attention focus of the person wearing the camera. We present EYEWATCHME, an integrated vision and state estimation system that at the same time tracks the positions and the poses of the acting hands, the pose that the manipulated object, and the pose of the observing camera. Taken together, EYEWATCHME provides comprehensive data for learning predictive models of vision-guided manipulation that include the objects people are attending, the interaction of attention and reaching/grasping, and the segmentation of reaching and grasping using visual attention as evidence. Key technical contributions of this paper include an ego view hand tracking system that estimates 27 DOF hand poses. The hand tracking system is capable of detecting hands and estimating their poses despite substantial selfocclusion caused by the hand and occlusions caused by the manipulated object. EYEWATCHME can also cope with blurred images that are caused by rapid eye movements. The second key contribution is the of the integrated activity recognition system that simultaneously tracks the attention of the person, the hand poses, and the poses of the manipulated objects in terms of a global scene coordinates. We demonstrate the operation of EYEWATCHME in the context of kitchen tasks including filling a cup with water. © 2009 IEEE.","Title: Cyclic-Shifting Based Sequential Cooperative Spectrum Sensing Strategy for Multi-Channel Cognitive Radio Networks.\nYear: 2015\n\nAbstract: Traditional multi-channel cooperative spectrum sensing (CSS) scheme schedules a group of cognitive users (CU) to sense a particular channel in any given sensing slot, which means that the same sensing sequence pattern is shared by all CUs in the group. Although the sensing accuracy can be improved, the energy consumption will correspondingly increase. In order to reduce the energy consumption without loss of the sensing accuracy, we in this paper propose a cyclic-shifting based sequential CSS strategy for multi-channel cognitive networks (CN). Specifically, instead of employing the common shared sensing sequence pattern, our proposed strategy assigns a unique cyclic-shifting based sensing sequence for each CU, such that different channels will be sensed simultaneously in any given sensing slot. Moreover, if the decision for a particular channel can be made by current sensing information, the channel will not be sensed in the following sensing slots. Theoretical analysis shows that our proposed strategy can efficiently reduce the number of both sensing slots and reporting slots consumed for each channel and achieve the same probabilities of detection and false-alarm as the traditional CSS scheme. This implies that the energy efficiency of the system can be improved while maintaining the sensing accuracy undegraded. Simulation results are also provided to demonstrate the superiority of our proposed strategy as compared to the existing scheme.","Title: Antenna Tilt Assignment for Three-Dimensional Beamforming in Multiuser Systems.\nYear: 2015\n\nAbstract: In recent years, many approaches have been introduced in next generation (5G) wireless cellular networks in response to the demands for higher data rates and broader coverage. In this paper, a novel downlink three-dimensional (3D) beamforming scheme is proposed for the 5G multiuser multiple-input multiple-output (MU-MIMO) system. This scheme separates beams in the so-called elevation domain via base station (BS) antenna tilt assignment, with the objective of reducing inter-user interference. The key to this scheme is controlling the vertical radiation pattern of BS antennas, which is realized by more efficient use of a two-dimensional (2D) planar antenna array. Moreover, we give the optimal solution of 3D beamforming to maximize the users average data rate, including adjustments of the antenna array and the corresponding multiuser selection algorithm. This can be used as a systematic framework for any given 3D scenario to mitigate inter-user interference. Our simulation results demonstrate the performance benefits in terms of transmission rate in comparison with traditional schemes.","Title: Joint Battery-Buffer Sustainable Guarantees in Energy-Harvesting Enabled Wireless Networks.\nYear: 2015\n\nAbstract: In light of the drastically-increasing demands on ubiquitous information acquisition and exchange, battery-powered devices are playing a more critical role in wireless networking, which inspires and expedites the development of energy-harvesting techniques. The sustainability requirements for such devices include two mutual-impacting dimensions: energy supply avoiding battery outage and stable transmissions avoiding buffer overflow. We in this paper propose a power-and-rate adaption scheme subject to the constraints on buffer-overflow probability and battery-outage probability in energy-harvesting enabled networks, which aims at maximizing the system throughput. The two probability constraints address the statistical assurance for the two-dimensional sustainability, which is suitable to dealing with the highly unpredictable energy-harvesting and channel fading statuses. Specifically, by applying the asymptotic queuing analyses to data-transmission and energy-harvesting processes, we can characterize both of the battery-outage and buffer-overflow probabilities via the effective-capacity/-bandwidth theories. Then, we formulate the effective-capacity optimization problem, which maximizes the sustainable throughput while complying with the statistical buffer-overflow and battery-outage constraints, and solve for the optimal power-adaptation scheme. We also conduct abundant simulations to evaluate our scheme's performances, demonstrate the superiority of our proposed scheme over existing baseline schemes, as well as study the impact of sustainability requirements on the performances.","Title: AF-Based CSI Feedback for User Selection in Multi-User MIMO Systems.\nYear: 2015\n\nAbstract: In this paper, we propose a joint amplify-and-forward (AF)-based channel estimation and user selection (J-ACES) scheme for multi-user MIMO (MU-MIMO) systems. Firstly, without channel state information (CSI) quantization, the transmitter estimates the downlink CSI for each receiver by adopting AF-based CSI feedback mechanism, in which the receiver amplifies and feeds back its own received downlink pilot symbols to the transmitter. An analytic user normalized mean square error (UNMSE) characterization of the uplink channel estimation and a lower bound of UNMSE for the downlink channel estimation are respectively derived and verified by Monte Carlo simulations. We show how the performance of UNMSE is influenced by the uplink and downlink pilot signal to noise ratio (SNR). Secondly, we obtain a corresponding suboptimal beamformer and estimated Signal to Interference Plus Noise Ratio (SINR) for each receiver to minimize the influence of estimation error on the subsequent user selection based on semi-orthogonal user selection (SUS). Finally, a mechanism that each selected receiver is informed of all the selected receiver beamformers to adopt the minimum mean square error (MMSE) detector is performed for further reducing the error caused by the uncertainty of the user selection. Simulation results show that the proposed scheme can improve the system spectral efficiency and has robust spectral efficiency gain even under the condition that the uplink pilot SNR is 20dB lower than the downlink pilot SNR, as compared to Quasi-MMSE Weight (QMW) scheme.","Title: Securing Wireless Transmission against Reactive Jamming: A Stackelberg Game Framework.\nYear: 2015\n\nAbstract: Reactive jamming, which performs jamming attacks on condition of detecting the legitimate transmissions, is widely considered as one of the most serious security challenges in wireless communications. In this paper, we tackle the reactive jamming issue from a novel yet realistic perspective - the jammer may not always be able to accurately detect the legitimate transmissions, which in turn, can be exploited by the legitimate user to enhance security. In accordance with the detection-then-jamming characteristic of reactive jamming, we formulate the transmitting-jamming problem within a Stackelberg game framework, where the legitimate user takes action first, followed by the reactive jammer. To optimize its own utility, the legitimate user needs to determine the transmission strategy by elaborately achieving the tradeoff between the signal-to-interference-plus-noise ratio (SINR) and the probability to be accurately detected and thus jammed by its adversary. The investigation on Stackelberg equilibrium provides the solution to the game model. Furthermore, we consider the more practical situation that the legitimate user has only incomplete knowledge regarding its adversary and analyze the corresponding impact on the game and equilibrium. Simulation results demonstrate significant performance superiority in terms of secure legitimate transmissions compared with the classical approach.","Title: Context weight considered for implicit feature extracting\nYear: 2015\n\nAbstract: Researchers have been devoted to using context to extract implicit features. However, little concerns have been given to the situation that not all the contexts are meaningful. To solve this problem, we present a new method to evaluate the contribution of the contexts for extracting. We build an improved Co-occurrence matrix that containing the distance between an opinion word and different contexts. And then a LDA topic model is used to get the topic probability of the opinion word. The weight of context can be obtained by using cosine similarity in the improved Co-occurrence matrix and LDA topic model. We design a formula to extract implicit features with the consideration of context and topic. Experiments have showed that our method provides higher accuracy in extracting the implicit features.","Title: User cooperation analysis under eavesdropping attack: A game theory perspective\nYear: 2014\n\nAbstract: In this paper, the user cooperation behaviors under eavesdropping attack are analyzed through game theory. Considering the physical layer security, we prove that the conventional cooperation scheme actually deteriorates the secrecy performance compared to the direct transmission, given that the eavesdropper has a better channel condition to the users than the destination. In this case, the necessary condition of the cooperation that the users should obtain additional utilities from the cooperation is not satisfied, which makes the users have no incentive to participate in the cooperation game. In order to motivate users, an adaptive cooperation scheme is designed to improve the secrecy performance even if the eavesdropping channel is superior to the destination's channel, and it is also observed that the mutual cooperation is one of the Nash equilibriums. We further exploit the Stackelberg game with a punishment mechanism to make the mutual cooperation as the unique Nash equilibrium.","Title: Poster: Enabling Hands-free Drawing on WiFi Devices\nYear: 2015\n\nAbstract: We present the high-level design of WiDraw, the first 3D hand motion tracking system using COTS WiFi cards, proposed in [3]. WiDraw can track hand gestures without a priori learning or requiring the user to hold any hardware. It can be implemented on existing mobile devices using only a software patch. WiDraw exploits the Angle-of-Arrival values of incomingWiFi signals at aWiFi device and enables hand trajectory tracking in both LOS and NLOS scenarios. WiDraw's high tracking accuracy allows the users to send arbitrary input to their WiFi devices, opening up a whole new class of applications in human-computer interactions.","Title: Improving Connectivity, Coverage, and Capacity in 60 GHz Indoor WLANs Using Relays\nYear: 2015\n\nAbstract: 60 GHz technology, standardized by IEEE 802.11ad, has emerged as an alternative to 2.4/5 GHz legacy WiFi for building multi-Gigabit general purpose home/enterprise WLANs. However, limited range and high vulnerability to blockage of millimeter-wave (mmWave) links can severely affect WLAN performance. These problems coupled with long re-connection time for a broken link pose a major challenge to the realization of 60 GHz WLANs. In this work, we look at the relay architecture defined in the 802.11ad standard as a solution to these issues and propose extensions to it for achieving gains in both WLAN coverage and capacity.","Title: WiDraw: Enabling Hands-free Drawing in the Air on Commodity WiFi Devices\nYear: 2015\n\nAbstract: This paper demonstrates that it is possible to leverage WiFi signals from commodity mobile devices to enable hands-free drawing in the air. While prior solutions require the user to hold a wireless transmitter, or require custom wireless hardware, or can only determine a pre-defined set of hand gestures, this paper introduces WiDraw, the first hand motion tracking system using commodity WiFi cards, and without any user wearables. WiDraw harnesses the Angle-of-Arrival values of incoming wireless signals at the mobile device to track the user's hand trajectory. We utilize the intuition that whenever the user's hand occludes a signal coming from a certain direction, the signal strength of the angle representing the same direction will experience a drop. Our software prototype using commodity wireless cards can track the user's hand with a median error lower than 5 cm. We use WiDraw to implement an in-air handwriting application that allows the user to draw letters, words, and sentences, and achieves a mean word recognition accuracy of 91%.","Title: Towards Motion-Aware Wireless LANs Using PHY Layer Information\nYear: 2015\n\nAbstract: The increasing popularity of WiFi brings new challenges in the design of wireless protocols but at the same time creates exciting opportunities for novel ways of exploiting WiFi technology in a variety of applications. On one hand, the smaller form factor of today's WiFi devices allows WiFi users to access wireless networks under mobility, calling for new, mobility-aware wireless protocols that are able to sustain high performance, on the other hand, the ubiquity of WiFi devices has recently raised interest in extending WiFi's capabilities beyond communication, e.g., for human-computer interaction. In this paper, we demonstrate that it is possible to enable fine-grained human motion detection on commodity WiFi devices by exploiting PHY layer information exposed by today's WiFi chipsets. We propose two motion detection techniques for two different application scenarios and explore their benefits on protocol performance and human-device interaction, respectively.","Title: Optimization of Postal Distribution Network Based on Rendezvous with Heterogeneous Vehicles and Capacity Constraints\nYear: 2015\n\nAbstract: High unloaded ratio of trucks is one of the key factors that incur high costs of mail transportation in China's postal network. How to reduce unnecessary deadhead kilometers of trucks is worthy of being researched. In this paper, we take heterogeneous trucks and facility capacity into consideration of optimizing the postal express line network using Rendezvous driving pattern of trucks. A mixed integer non-linear programming model is built and a corresponding mixed genetic algorithm is developed to solve the model. A numerical simulation is also designed to verify the validity of the model and the algorithm developed in this research. Through a comparison of Rendezvous and direct travel mode, some insights of Rendezvous are presented. (C) 2015 The Authors. Published by Elsevier B.V.","Title: Dynamic Allocation of RACH Resource for Clustered M2M Communications in LTE Networks.\nYear: 2015\n\nAbstract: In this paper, we propose a dynamic allocation scheme of random access channel (RACH) resource for clustered machine-to-machine (M2M) communications, in which delay-sensitive services coexist with delay-tolerant ones. Our scheme aims at alleviating the overload and congestion of machine-type (MTC) communication as well as satisfying both delay-sensitive and delay-tolerant services. Specifically, the operation of our protocol includes three aspects. First, in order to make full use of the preamble resources controlled by the Enhanced Node B (eNB), our proposed scheme adopts a two-cluster networking, where MTC devices are divided into two clusters based on their requirements on delay. Second, we develop the dynamic allocation scheme to partition the available preambles for each cluster under the condition of guaranteeing the preferable number of successful devices. Third, the devices belonging to different clusters adopt the access class barring (ACB) mechanism respectively. Simulation results show that our proposed scheme realizes the remarkable increase in improving the access success probability and achieve performance improvement in reducing access delay.","Title: Interference Cancellation Based Transmission Strategy Using Primary Arq For Cooperative Crns\nYear: 2015\n\nAbstract: Aiming at efficient utilizing the licensed spectrum, in this paper, we develop an interference cancellation based transmission strategy (ICTS) for the cooperative cognitive radio networks (CRN) which will take advantage of the opportunities that arise during the primary automatic repeat requests (ARQ) and cancel the primary interference in both the primary initial transmission and retransmission slots. Simultaneously, the secondary system will cooperate with the primary system by supporting its outage quality-of-service (QoS) requirement to speedup the primary transmission and acquire more interferencefree spectrum opportunities. Specifically, in the primary initial transmission slot, the secondary users (SU) will transmit in the underlay mode. In addition, SUs try to decode the primary signal to cancel the primary interference and overhear the primary ARQ signal. In the retransmission slot, SUs can cancel the primary interference directly when the primary signal is successfully decoded in the initial slot or utilize the primary information redundancy to cancel the interference. With statistical channel state information (CSI), SUs can calculate their interference cancellation probabilities in both slots and derive their average transmission rate. To maximize SUs' average transmission rate while meeting PUs outage QoS requirement, we formulate the optimization problem and efficiently allocate SUs transmit power. The closed-form expressions of the average transmission rates for both PUs and SUs are derived. Furthermore, SUs' upper bound symbol error probability (SEP) and PUs' SEP are derived. Simulation results demonstrate the performance superiority of our developed ICTS over conventional ARQ-based transmission strategies in terms of SUs' average throughput and PUs' outage probability and SEP.","Title: Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.\nYear: 2016\n\nAbstract: The prosperity of e-health is boosted by fast development of medical devices with wireless communications capability such as wearable devices, tiny sensors, monitoring equipments, etc., which are randomly distributed in clinic environments. The drastically-increasing population of such devices imposes new challenges on the limited wireless resources. To relieve this problem, key knowledge needs to be extracted from massive connection attempts dispersed in the air towards efficient access control. In this paper, a hybrid periodic-random massive access (HPRMA) scheme for wireless clinical networks employing ultra-narrow band (UNB) techniques is proposed. In particular, the proposed scheme towards accommodating a large population of devices include the following new features. On one hand, it can dynamically adjust the resource allocated for coexisting periodic and random services based on the traffic load learned from signal collision status. On the other hand, the resource allocation within periodic services is thoroughly designed to simultaneously align with the timing requests of differentiated services. Abundant simulation results are also presented to demonstrate the superiority of the proposed HPRMA scheme over baseline schemes including time-division multiple access (TDMA) and random access approach, in terms of channel utilization efficiency, packet drop ratio, etc., for the support of massive devices' services.","Title: Initial position estimation strategy for a surface permanent magnet synchronous motor used in hybrid electric vehicles.\nYear: 2016\n\nAbstract: A novel nonlinear model for surface permanent magnet synchronous motors (SPMSMs) is adopted to estimate the initial rotor position for hybrid electric vehicles (HEVs). Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis (FEA) model is presented first. Hybrid injection of a static voltage vector (SVV) superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive.","Title: Physical layer security based on real interference alignment in K-user MIMO Y wiretap channels\nYear: 2016\n\nAbstract: In this paper, we study the information-theoretical security of the K-user MIMO Y wiretap Gaaussian channels and deduce the lower bounds of the secure degrees of freedom (SDOF). Due to the different receiving links of the eavesdropper, we propose two MIMO Y wiretap models which are called Broadcast Wiretap Channel (BWC) and Multi-access Broadcast Wiretap Channel (MBWC), respectively. Each legitimate user equipped with M antennas intends to transmit independent signals via an intermediate amplify-and-forward (AF) relay with N antennas. Besides, there exists an eavesdropper with Ne antennas close to the K users (K ≥ 3). Based on the asymptotic real interference alignment and the structured cooperative jamming, the security of the MIMO Y wiretap channels can be guaranteed. From the asymptotic analysis, we can find that a lower bound of the sum SDOF in BWC is K/4. While in the MBWC model, since the relay working in the full duplex mode broadcasts cooperative jamming signals to all the other nodes especially to the eavesdropper, the lower bound of sum SDOF is K\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\n-3K/4(K-1), which is altered along with the number of users.","Title: Samer Plus : Balancing Short Term Throughput And Long Term Stability In Cognitive Radio Mesh Networks\nYear: 2016\n\nAbstract: A large number of routing protocols for Cognitive radio networks (CRNs) have been proposed recently, each based on different design goals, and evaluated in different scenarios, under different assumptions. In our previous work, we conducted the first extensive empirical performance study of routing protocols for CRNs - Coolest Path, SAMER, and CRP - under the same realistic set of assumptions. Our study revealed that SAMER significantly outperforms the other protocols under low primary user activity but its performance degrades under high PU activity.In this work, we introduce an enhanced version of SAMER (SAMER+) that performs consistently well in both low and high PU activity scenarios. The core of SAMER+ is a new path metric that balances short term throughput and long term path stability. We evaluate SAMER+ using extensive simulations and compare it against SAMER and Coolest Path. Our results show that SAMER+ significantly outperforms both protocols in a variety of scenarios.","Title: On Achievable Secrecy Rate By Noise Aggregation Over Wireless Fading Channels\nYear: 2016\n\nAbstract: Noise aggregation is an efficient way of aggregating the inherent noises introduced during wireless transmissions over multiple channels to degrade the eavesdropper's channel quality. While the performance of channel aggregation has not been thoroughly studied over wireless fading channels, we in this paper concentrating on analyses of its achievable average secrecy rate with emphasis on binary symmetric channel (BSC), whose crossover probability is a time-varying process. The advantage of noise aggregation over traditional transmission in fading environments is demonstrated by our analyses and simulations. Simulation results show that the noise aggregation scheme can achieve a remarkable increase in terms of average secrecy rate even if the eavesdropper has better average channel quality than the legitimate receiver.","Title: Active jamming for multi-user information security improvement with the access statuses of users.\nYear: 2016\n\nAbstract: We propose a novel physical layer scheme for improving multiple users' information security e.g., vehicle devises and mobile terminals in the next-generation communication systems. Owing to the limitation of service node's antennas, not all users can be concurrently served. Therefore, the node only provides services for some chosen users in a certain time. On the basis of this premise, in our scheme, the access status of each user is involved. With the information of access status, the node devises transmitters to increase the served users' transmission rates and decrease the possibility of each idle user's signal interception. Furthermore, the node executes active jamming according to the realistic situation of this multi-user network for confusing the idle users/potential eavesdroppers. In addition, with the gradually mature applications of full-duplex techniques for the terminals, each user can also implement active jamming in the full-duplex mode to interfere with the potential eavesdroppers. It is seen that our scheme is linear without iteration, and performance analysis and simulation results illustrate that it is feasible for multi-user security enhancement. Copyright © 2016 John Wiley & Sons, Ltd.","Title: Robot Vision Architecture for Autonomous Clothes Manipulation.\nYear: 2016\n\nAbstract: This paper presents a novel robot vision architecture for perceiving generic 3D clothes configurations. Our architecture is hierarchically structured, starting from low-level curvatures, across mid-level geometric shapes u0026 topology descriptions; and finally approaching high-level semantic surface structure descriptions. We demonstrate our robot vision architecture in a customised dual-arm industrial robot with our self-designed, off-the-self stereo vision system, carrying out autonomous grasping and dual-arm flattening. It is worth noting that the proposed dual-arm flattening approach is unique among the state-of-the-art robot autonomous system, which is the major contribution of this paper. The experimental results show that the proposed dual-arm flattening using stereo vision system remarkably outperforms the single-arm flattening and widely-cited Kinect-based sensing system for dexterous manipulation tasks. In addition, the proposed grasping approach achieves satisfactory performance on grasping various kind of garments, verifying the capability of proposed visual perception architecture to be adapted to more than one clothing manipulation tasks.","Title: Detecting Anomalous User Behavior Using an Extended Isolation Forest Algorithm: An Enterprise Case Study.\nYear: 2016\n\nAbstract: Anomalous user behavior detection is the core component of many information security systems, such as intrusion detection, insider threat detection and authentication systems. Anomalous behavior will raise an alarm to the system administrator and can be further combined with other information to determine whether it constitutes an unauthorised or malicious use of a resource. This paper presents an anomalous user behaviour detection framework that applies an extended version of Isolation Forest algorithm. Our method is fast and scalable and does not require example anomalies in the training data set. We apply our method to an enterprise dataset. The experimental results show that the system is able to isolate anomalous instances from the baseline user model using a single feature or combined features.","Title: Two Birds With One Stone: Towards Secure and Interference-Free D2D Transmissions via Constellation Rotation.\nYear: 2016\n\nAbstract: This paper studies the cooperative device-to-device (D2D) transmissions in cellular networks, where two D2D users communicate bidirectionally with each other and simultaneously serve as relays to assist the two-way transmissions between two cellular users. For this scenario, both cellular and D2D links share the same spectrum, thus creating mutual interference. In addition to that, a security prob...","Title: Control of a Class of Industrial Processes With Time Delay Based on a Modified Uncertainty and Disturbance Estimator.\nYear: 2016\n\nAbstract: The control algorithm based on the uncertainty and disturbance estimator (UDE) is considered as an efficient control strategy that has attracted much attention recently. However, it cannot be directly applied to the widely existing industrial processes with time delay. To extend its applicability, the UDE control algorithm is modified so that it can be applied to stable, integrating, and unstable ...","Title: Dynamic RACH Partition for Massive Access of Differentiated M2M Services.\nYear: 2016\n\nAbstract: In machine-to-machine (M2M) networks, a key challenge is to overcome the overload problem caused by random access requests from massive machine-type communication (MTC) devices. When differentiated services coexist, such as delay-sensitive and delay-tolerant services, the problem becomes more complicated and challenging. This is because delay-sensitive services often use more aggressive policies, and thus, delay-tolerant services get much fewer chances to access the network. To conquer the problem, we propose an efficient mechanism for massive access control over differentiated M2M services, including delay-sensitive and delay-tolerant services. Specifically, based on the traffic loads of the two types of services, the proposed scheme dynamically partitions and allocates the random access channel (RACH) resource to each type of services. The RACH partition strategy is thoroughly optimized to increase the access performances of M2M networks. Analyses and simulation demonstrate the effectiveness of our design. The proposed scheme can outperform the baseline access class barring (ACB) scheme, which ignores service types in access control, in terms of access success probability and the average access delay.","Title: Development and Application of a Next Generation Air Sensor Network for the Hong Kong Marathon 2015 Air Quality Monitoring.\nYear: 2016\n\nAbstract: This study presents the development and evaluation of a next generation air monitoring system with both laboratory and field tests. A multi-parameter algorithm was used to correct for the impact of environmental conditions on the electrochemical sensors for carbon monoxide (CO) and nitrogen dioxide (NO2) pollutants. The field evaluation in an urban roadside environment in comparison to designated monitors showed good agreement with measurement error within 5% of the pollutant concentrations. Multiple sets of the developed system were then deployed in the Hong Kong Marathon 2015 forming a sensor-based network along the marathon route. Real-time air pollution concentration data were wirelessly transmitted and the Air Quality Health Index (AQHI) for the Green Marathon was calculated, which were broadcast to the public on an hourly basis. The route-specific sensor network showed somewhat different pollutant patterns than routine air monitoring, indicating the immediate impact of traffic control during the marathon on the roadside air quality. The study is one of the first applications of a next generation sensor network in international sport events, and it demonstrated the usefulness of the emerging sensor-based air monitoring technology in rapid network deployment to supplement existing air monitoring.","Title: Security Enhanced Via Dynamic Fountain Code Design For Wireless Delivery\nYear: 2016\n\nAbstract: Guaranteeing the secure delivery is a critical yet challenging issue in wireless transmission. In this paper, a secure delivery scheme that utilizing the dynamic fountain code design is proposed. Using fountain-coded transmission, the transmitter continuously sends fountain packets until the legitimate receiver successfully recovers the original data from a sufficient number of fountain packets. Secure delivery can be guaranteed if the eavesdropper overhears inadequate fountain packets to recover the original data. Inspired by this insight, we propose a fountain-encoded scheme in transmitter which adopts the feedback from the legitimate receiver as the encoding motivation. By dynamically adjusting the fountain-encoded mechanism based on the message fed back from legitimate user, the proposed scheme is beneficial to enhance the decoding rate of legitimate receiver. Further, we analyse the performance for the intercept probability as well as the transmission efficiency of the transmitter. Simulation results confirm our analytical results and demonstrate that, compared with the counterparts, our proposed scheme more effectively guarantees secure wireless delivery with lower intercept probability and higher transmission efficiency.","Title: Advanced fault-tolerant current control of five-phase PMSM for mining applications.\nYear: 2016\n\nAbstract: The next big change in mining technology is associated with using more power dense motors, such as permanent magnet synchronous motors (PMSM). For added robustness and fault tolerance, multiphase PMSM can be recommended. Focus of this paper is development of an advanced current control scheme for five-phase PMSM under normal conditions and one-phase open-fault. While traditional linear controllers can cope well with current reference tracking in the healthy motor conditions, but post fault operation involves unmodelled dynamics, which significantly reduces the effectiveness of linear controllers. The proposed non-linear control scheme is based on decoupled fault motor model and sliding mode control (SMC). It is capable of providing constant d and q axis current and constant back-EMFs, even if the motor is missing one phase. With this approach the faulty motor has a smooth output speed profile. This makes it efficient and suitable for demanding drive applications, such as mining machinery. Feasibility of the proposed control strategy is experimentally verified on a FPGAIDCS based five-phase PMSM drive.","Title: Hybrid Secure Beamforming And Vehicle Selection Using Hierarchical Agglomerative Clustering For C-Ran-Based Vehicle-To-Infrastructure Communications In Vehicular Cyber-Physical Systems\nYear: 2016\n\nAbstract: The architecture of C-RAN-based soft-defined vehicular networks can support increasing demands of various applications in the future vehicular cyber-physical systems, but lacks strong and practical security-enhancing mechanisms in the physical layer. In this article, we propose a hybrid beamforming and vehicle-selection framework for vehicle-to-infrastructure communications to broadcast high-speed confidential messages. A one-dimensional roadway scenario having multiple lanes is considered, and the concept of secure region and interference-selection region is, respectively, developed for each roadside unit. We formulate an optimization problem of maximizing secrecy sumrate with the constraint of orthogonality-based vehicle selection. The original problem is then divided into two subproblems subtly. In terms of the first subproblem, we, by exploiting the orthogonality assumption, obtain a corresponding secure beamformer for each vehicle located in the secure region to reduce the interference and confidential information leakage. Based on secure beamformers, the second subproblem is changed to be a vehicle-selection problem, which is then solved by adopting hierarchical agglomerative clustering method and implemented by two proposed novel algorithms blending vehicle selection with beamformer generation. Simulation results verify the effectiveness of the proposed algorithms in the respect of secrecy sumrate compared with the conventional zero-forcing beamforming using semi-orthogonal user selection algorithms. Furthermore, simulations show how our proposed algorithms resist against eavesdropping from collusive vehicles located in the same secure region by flexibly altering the size of secure region and interference-selection according to the traffic density.","Title: Micromotion Feature Extraction and Distinguishing of Space Group Targets.\nYear: 2017\n\nAbstract: Traditional micro-Doppler (m-D) analysis theories largely focus on isolated targets, making these theories difficult to utilize in monitoring and recognizing space group targets. This letter proposes an algorithm for separating ballistic group targets based on the extraction of micromotion features. Modeling the ballistic targets as cone-cylinder models, the skeleton extraction method in morpholog...","Title: Backup sourcing with capacity reservation under uncertain disruption risk and minimum order quantity.\nYear: 2017\n\nAbstract: We develop a backup sourcing strategy through capacity reservation contract under supply disruptions.The buyer's optimal sourcing decisions as well as the backup supplier's optimal reservation price are derived.Different disruption levels are integrated and their impacts are investigated.The effects of flexible backup capacity with MOQ constraint on the contract terms are examined.We show that the both the buyer and the backup supplier may benefit from the MOQ constraints. Ample evidence has confirmed the importance of backup sourcing when disruption of the major supply source is inevitable. The decisions associated with how to work with the backup supplier to ensure backup or emergency supply when the primary source experiences shortfall have received a great deal of attention. We study a capacity reservation contract between a buyer and a backup supplier when there is uncertainty about the major supplier's disruption risks. Additionally, we consider the constraint that requires the buyer to order either none or at least a minimum order quantity in the case of contingent sourcing. By committing to such backup contracts, the buyer seeks to lower its contingent purchasing cost and to ensure the availability of merchandise in the presence of risks. The involving players' optimal decisions are investigated theoretically and the impacts of the key parameters and special scenarios are assessed numerically. The study contributes to the literature by providing a better understanding of how to use a capacity reservation contract as a vehicle to build long-term relationship in backup sourcing and of the impacts of disruption uncertainty and contingent supply availability.","Title: Cooperative Privacy Preserving Scheme for Downlink Transmission in Multiuser Relay Networks.\nYear: 2017\n\nAbstract: This paper studies the privacy-preserving for downlink transmission in multiuser relay networks, where a source communicates with multiple users via a relay employing the amplify-and-forward protocol. Within any scheduling unit, only one user (desired user) is chosen for data reception, and the other users (undesired users) are viewed as potential eavesdroppers due to the broadcast nature of wireless medium. To prevent information leakage, we propose a physical-layer cooperative privacy preserving scheme, whose key idea is to schedule a cooperating user in addition to the desired user to deliver artificial noise (AN). By exploiting the characteristics of channels, the cooperating user carefully designs the AN transmitted during two time slots such that the AN can be canceled out at the desired user, but cannot be removed at the undesired users. As a result, the end-to-end signal-to-noise-ratio of any undesired user is heavily degraded, while that of the desired user is not seriously affected, thus preserving the data confidentiality of the desired user. To maximize the instantaneous secrecy rate, an opportunistic user selection criterion is developed. The lower bound of the ergodic secrecy rate (ESR) as well as the approximate upper bound of the secrecy outage probability is derived. The asymptotic performance of ESR is also analyzed via extreme value theory. Furthermore, to motivate users with heterogeneous channel conditions to participate in cooperation and guarantee the fairness among users, a user-grouping-based selection method is proposed. To evaluate the performance of this method, a novel concept called system fairness factor is introduced and studied. Theoretical analysis and simulation results show that, thanks to the proposed cooperative privacy preserving mechanism, the system ESR grows with the increasing number of users, and much higher secrecy rate and lower secrecy outage probability can be achieved compared with the existing schemes in the literature.","Title: Reciprocally-Benefited Secure Transmission for Spectrum Sensing-Based Cognitive Radio Sensor Networks.\nYear: 2016\n\nAbstract: The rapid proliferation of independently-designed and -deployed wireless sensor networks extremely crowds the wireless spectrum and promotes the emergence of cognitive radio sensor networks (CRSN). In CRSN, the sensor node (SN) can make full use of the unutilized licensed spectrum, and the spectrum efficiency is greatly improved. However, inevitable spectrum sensing errors will adversely interfere with the primary transmission, which may result in primary transmission outage. To compensate the adverse effect of spectrum sensing errors, we propose a reciprocally-benefited secure transmission strategy, in which SN's interference to the eavesdropper is employed to protect the primary confidential messages while the CRSN is also rewarded with a loose spectrum sensing error probability constraint. Specifically, according to the spectrum sensing results and primary users' activities, there are four system states in this strategy. For each state, we analyze the primary secrecy rate and the SN's transmission rate by taking into account the spectrum sensing errors. Then, the SN's transmit power is optimally allocated for each state so that the average transmission rate of CRSN is maximized under the constraint of the primary maximum permitted secrecy outage probability. In addition, the performance tradeoff between the transmission rate of CRSN and the primary secrecy outage probability is investigated. Moreover, we analyze the primary secrecy rate for the asymptotic scenarios and derive the closed-form expression of the SN's transmission outage probability. Simulation results show that: (1) the performance of the SN's average throughput in the proposed strategy outperforms the conventional overlay strategy; (2) both the primary network and CRSN benefit from the proposed strategy.","Title: Experimental Evaluation of WiFi Active Power/Energy Consumption Models for Smartphones.\nYear: 2017\n\nAbstract: We conduct an extensive experimental evaluation of a class of WiFi active power/energy consumption models for smartphones that are based on parameters readily available to the upper layers of the protocol stack. We first consider a number of parameters used by previous models and show their limitations. We then focus on a recent approach modeling the active power consumption as a function of the application layer throughput. We study the properties of a previously proposed throughput-based model in relation to other parameters such as the packet size and/or the transport layer protocol, and we evaluate its accuracy under a variety of scenarios that have not been considered in previous studies. Our results show that the model works well in a number of scenarios, with both 802.11n- and 802.11ac-equipped smartphones, and its accuracy can be largely improved with the knowledge of transport layer protocol and packet size. However, such knowledge makes the model more complex and results in largely reduced accuracy in high throughput settings or on hardware different from the one that was used for training. We further discuss a few practical issues related to the measurement and modeling methodology.","Title: Road curve fitting by multi-resolution analysis\nYear: 2016\n\nAbstract: In this paper, we propose a new method for road curve fitting in urban environment based on multi-resolution analysis. The main technical contributions of the proposed method are the reconstructed approximation on the basis of the wavelet decomposition structure for curve fitting and the de-noising via the wavelet coefficients thresholding. The carried out experimental tests show promising results in a series of continuous driving images, validating our suggested method can fit the road curve effectively and computational efficiently.","Title: Security Protection Over Wireless Fading Channels By Exploiting Frequency Selectivity\nYear: 2016\n\nAbstract: Secure wireless communication has always been a hot research topic due to the vulnerabilities associated with wireless channel Physical layer aspects to secure wireless communication, based on the information-theoretic security and signal processing methods have gained much recognition over the last. decade. Specifically, artificial noise (AN) methods are assumed to be good means for providing security against potential eavesdroppers in multi-input multi-output (MIMO) systems and/or relay systems. However, there are still a large number of nodes which do not have multi-antennas or support sophisticated protocols in wireless networks. In this paper, a novel AN-aided method is proposed to secure wireless communications between the legitimate users (not equipped with multiple antennas) in the presence of an eavesdropper. In this proposed method frequency selective property of wireless channel is exploited. The basic principle is same in which transmitter generate random AN signal utilizing some of the transmission power to confuse eavesdropper. However artificial noise is generated in such a way that it appears to be zero at the sampling time, only for the legitimate receiver while degrading eavesdropper's channel. Artificial noise is specified using the channel state information (CSI) of the legitimate users' link. However, the secrecy of proposed scheme doesn't depend on the secrecy of CSI. Extensive simulation suggests that the proposed scheme can effectively utilized for securing wireless transmissions.","Title: Spatial Modulation Aided Physical Layer Security Enhancement For Fading Wiretap Channels\nYear: 2016\n\nAbstract: In this paper, the spatial modulation (SM) technique is explored to improve physical layer security in time-division duplex (TDD) wireless communication network. In the designed transmission scheme, the transmitter first exploits the knowledge of legitimate channel state information (CSI) to redefine the transmit antennas' indices which are used to map into spatial bits, then selects one activated antenna based on the renaming rule to transmit the modulation symbol. The communications security can be improved because the eavesdropper cannot detect the spatial bits information without the perfect legal CSI. Our studies derive the secrecy mutual information of the presented method. The numerical results on secrecy mutual information and bit error rate (BER) demonstrate the effectiveness and robustness of the proposed secrecy communications scheme.","Title: Secure Communication Using Noisy Feedback.\nYear: 2016\n\nAbstract: In this paper, the critical effect of noisy feedback in improving the physical layer security is investigated. Unlike previous works, where the eavesdropper's channel state information (either the instantaneous channel state information or the channel distribution information) is assumed known, a feedback and jamming scheme without any eavesdropper's channel state information is studied, which allows both the source and legal destination to transmit private message and degrade the eavesdropper alternatively in different phase of the transmission. More specifically, the situation in which no power constraint is considered first, and it shows using channel inversion a positive secrecy rate can always be achieved by mixing proper amount of artificial noise in the private signal, and the secrecy rate grows linearly with the power of private message in dB. Then we consider the practical situation with power constraint. Interestingly, it shows that a positive secrecy rate can also be obtained by using truncated channel inversion and selecting proper cutoff value and jamming power. Finally, the numerical results verify our analysis.","Title: Cooperative Physical-Layer Approach for Downlink Privacy Preserving in Multiuser Relay Networks.\nYear: 2016\n\nAbstract: This paper studies privacy-preserving for downlink transmission in multiuser relay systems, where a source communicates with multiple users via a relay employing the amplifyand- forward (AF) protocol. At any scheduling unit, only one user (desired user) is selected to receive the source information, and the other users (undesired users) are viewed as potential eavesdroppers due to the broadcast nature of wireless medium. A cooperative physical-layer scheme is proposed to prevent information leakage. The key idea of this scheme is to schedule a cooperating user in addition to the desired user to deliver the artificial noise (AN). By exploiting the characteristics of channels, the cooperating user carefully designs the AN transmitted during two time slots such that the AN can be cancelled out at the desired user, but can not be removed at the undesired users. As a result, the detection performance of the desired user is free of interference, while that of undesired users is heavily degraded, thereby preserving the data confidentiality of the desired user. To maximize the secrecy rate of the system, a user scheduling policy is developed. Further, the lower bound of the ergodic secrecy rate (ESR) is derived, and its asymptotic behavior is analyzed via extreme value theory (EVT). Theoretical analysis and simulation results show that, thanks to the proposed cooperative AN injection mechanism, the system ESR grows with the increasing number of users, and much higher secrecy rate can be achieved compared to the existing schemes in literature.","Title: Optimal power allocation for cognitive radio sensor networks under primary secrecy outage constraint\nYear: 2016\n\nAbstract: To secure the primary network, in this paper, we propose a cooperative spectrum access strategy in which the cognitive radio sensor network (CRSN) will cooperate with the primary network to protect the primary confidential messages against malicious eavesdropping and the quality of service (QoS) is supported. In the proposed scheme, the CRSN will exploit its interference on the eavesdropper to secure the primary transmission and as a reward, loose constraint of the spectrum sensing error probability is permitted for the CRSN. According the spectrum sensing results and the activities of primary network, there are four system states in the system. For each state, we will optimally allocate the transmit power of the CRSN so that the average transmission rate of the CRSN is maximized under the secrecy outage probability constraint of the primary network. Moreover, the closed-form expression of the transmit power for each state is derived. Simulation results demonstrate the performance superiority of our proposed strategy over the conventional overlay strategy in terms of SN's average throughput.","Title: A Hybrid Channel Estimation Strategy Against Pilot Spoofing Attack In Miso System\nYear: 2016\n\nAbstract: Pilot spoofing attack can deteriorate the transmission performance of the legitimate system and facilitate eavesdropping concurrently. Some detection methods of pilot attack have been proposed, while we consider the problem of channel estimation under pilot spoofing attack. In this paper, a hybrid channel estimation strategy using random Binary Phase Shift Keying (BPSK) is proposed. Specifically, a random BPSK sequence is transmitted by the legal user once the attack is detected. In this manner, the base station detects the sequence and re-estimates the legal channel with both contaminated pilot and assistant sequence. We evaluate the estimation performance in three cases according to different responses of the malicious user. Simulation results demonstrate that the proposed strategy can effectively estimate the legitimate channel against pilot attack.","Title: Deep LSTM Networks for Online Chinese Handwriting Recognition\nYear: 2016\n\nAbstract: Currently two heavy burdens are borne in online Chinese handwriting recognition: a large-scale training data needs to be annotated with the boundaries of each character and effective features should be handcrafted by domain experts. To relieve such issues, the paper presents a novel end-to-end recognition method based on recurrent neural networks. A mixture architecture of deep bidirectional Long Short-Term Memory (LSTM) layers and feed forward subsampling layers is used to encode the long contextual history trajectories. The Connectionist Temporal Classification (CTC) objective function makes it possible to train the model without providing alignment information between input trajectories and output strings. During decoding, a modified CTC beam search algorithm is devised to integrate the linguistic constraints wisely. Our method is evaluated both on test set and competition set of CASIA-OLHWDB 2. x. Comparing with state-of-the-art methods, over 30% relative error reductions are observed on test set in terms of both correct rate and accurate rate. Even to the more challenging competition set, better results can be achieved by our method if the out-of-vocabulary problem can be ignored.","Title: Noncontact Physiological Dynamics Detection Using Low-power Digital-IF Doppler Radar.\nYear: 2017\n\nAbstract: The instantaneous vital sign rates, which are related to physiological dynamics, are important indicators of human health condition. This paper presents a noncontact way to measure the human instantaneous vital signs using digital-intermediate frequency (IF) Doppler radar. The synchrosqueezing transform-based algorithm has been proposed to get a concentrated time-frequency (TF) distribution, so th...","Title: Secure Cooperative Transmission Against Jamming-Aided Eavesdropper for ARQ Based Wireless Networks.\nYear: 2017\n\nAbstract: Secure the cooperative transmission is studied for an automatic repeat request (ARQ)-based wireless network against a jamming-aided eavesdropper. The eavesdropper utilizes the jamming attack to assist its eavesdropping by forcing the legitimate transmitter to retransmit its confidential messages under poor wiretap channel quality. Then, utilizing these retransmission opportunities, the eavesdropper will eavesdrop the confidential message under good wiretap channel quality. To address the threat from the jammingaided eavesdropper in the ARQ-based wireless network, we propose an adaptive cooperative relaying and jamming secure transmission scheme to protect the confidential messages. In the proposed scheme, the legitimate receiver adopts the energy detection method to detect the jamming-aided eavesdropper's action and a cooperative node will aid the secure transmission through cooperative relaying under jamming attack or cooperative jamming under eavesdropping attack. By taking into account of the detection errors, we investigate the transmission outage probability and the secrecy outage probability, and derive their closed-form expressions for both one retransmission and multiple retransmissions scenarios. Numerical results are presented to verify the derived analytical results and demonstrate the performance superiority of the proposed scheme in terms of the secrecy outage probability.","Title: A fully end-to-end deep learning approach for real-time simultaneous 3D reconstruction and material recognition\nYear: 2017\n\nAbstract: This paper addresses the problem of simultaneous 3D reconstruction and material recognition and segmentation. Enabling robots to recognise different materials (concrete, metal etc.) in a scene is important for many tasks, e.g. robotic interventions in nuclear decommissioning. Previous work on 3D semantic reconstruction has predominantly focused on recognition of everyday domestic objects (tables, chairs etc.), whereas previous work on material recognition has largely been confined to single 2D images without any 3D reconstruction. Meanwhile, most 3D semantic reconstruction methods rely on computationally expensive post-processing, using Fully-Connected Conditional Random Fields (CRFs), to achieve consistent segmentations. In contrast, we propose a deep learning method which performs 3D reconstruction while simultaneously recognising different types of materials and labeling them at the pixel level. Unlike previous methods, we propose a fully end-to-end approach, which does not require hand-crafted features or CRF post-processing. Instead, we use only learned features, and the CRF segmentation constraints are incorporated inside the fully end-to-end learned system. We present the results of experiments, in which we trained our system to perform real-time 3D semantic reconstruction for 23 different materials in a real-world application. The run-time performance of the system can be boosted to around 10Hz, using a conventional GPU, which is enough to achieve realtime semantic reconstruction using a 30fps RGB-D camera. To the best of our knowledge, this work is the first real-time end-to-end system for simultaneous 3D reconstruction and material recognition.","Title: Weakly-supervised DCNN for RGB-D Object Recognition in Real-World Applications Which Lack Large-scale Annotated Training Data.\nYear: 2017\n\nAbstract: This paper addresses the problem of RGBD object recognition in real-world applications, where large amounts of annotated training data are typically unavailable. To overcome this problem, we propose a novel, weakly-supervised learning architecture (DCNN-GPC) which combines parametric models (a pair of Deep Convolutional Neural Networks (DCNN) for RGB and D modalities) with non-parametric models (Gaussian Process Classification). Our system is initially trained using a small amount of labeled data, and then automatically prop- agates labels to large-scale unlabeled data. We first run 3D- based objectness detection on RGBD videos to acquire many unlabeled object proposals, and then employ DCNN-GPC to label them. As a result, our multi-modal DCNN can be trained end-to-end using only a small amount of human annotation. Finally, our 3D-based objectness detection and multi-modal DCNN are integrated into a real-time detection and recognition pipeline. In our approach, bounding-box annotations are not required and boundary-aware detection is achieved. We also propose a novel way to pretrain a DCNN for the depth modality, by training on virtual depth images projected from CAD models. We pretrain our multi-modal DCNN on public 3D datasets, achieving performance comparable to state-of-the-art methods on Washington RGBS Dataset. We then finetune the network by further training on a small amount of annotated data from our novel dataset of industrial objects (nuclear waste simulants). Our weakly supervised approach has demonstrated to be highly effective in solving a novel RGBD object recognition application which lacks of human annotations.","Title: Anti-Eavesdropping Scheme Based on Quadrature Spatial Modulation.\nYear: 2017\n\nAbstract: To resist the passive eavesdropping while reserving the same hardware cost and receiver structure of the legitimate receiver, a secure quadrature spatial modulation (QSM) scheme is proposed in this letter. Instead of the information symbol, a mixture of the information symbol and artificial noise is transmitted through the activated transmit antennas. The mixed signals are designed, so that the artificial noise is cancelled at the legitimate receiver but cause random interference to the eavesdropper. The secrecy rate is analyzed and the optimal power allocation between the artificial noise and the information signal is investigated. The influence of the number of the eavesdropper's antennas is discussed. Simulation results show that, for multiple-input-single-output systems, the proposed secure QSM scheme achieves the best secrecy performance among the existing similar schemes by using less radio frequency chains. For multiple-input-multiple-output systems, the secure QSM scheme performs better than the existing secure SM scheme does under the same power constraint and transmission rate.","Title: Modified multiple measurement vectors model for squinted synthetic aperture radar imaging.\nYear: 2017\n\nAbstract: Inspired by the theoretical advances of compressed sensing, lots of sparsity-aware methods have been proposed for squinted synthetic aperture radar (SAR) imaging based on the single-measurement vector (SMV) model. Compared with SMV, the multiple measurement vectors (MMV) model has been demonstrated to have better reconstruction performance. In fact, echo received by SAR at different azimuth positions can be viewed as MMVs. However, the MMV model cannot be directly used in squinted SAR imaging, because MMV requires multiple sparse vectors of the common sparse structures, while the high-resolution range profiles (HRRPs) obtained by squinted SAR at different azimuth positions have different sparse structures due to range migration effect. A squinted SAR imaging method is proposed based on MMV. First, a modified MMV model that considers range migration is built to realize sparse representation of echo. Additionally, an improved orthogonal matching pursuit algorithm is developed to reconstruct HRRPs. Finally, a high-resolution two-dimensional image result can be easily achieved via traditional azimuth match filtering. Experimental results based on both simulated and real data demonstrate that the proposed MMV-based method can provide better computational efficiency and antinoise ability compared to the SMV-based method. (C) 2017 SPIE and IS&T","Title: Enhancing physical-layer security via big-data-aided hybrid relay selection.\nYear: 2017\n\nAbstract: The explosive growth in data traffic presents new challenges to the new generation of wireless communication systems, such as computing capabilities, spectrum efficiency and security. In this paper, we use the network structure, which is adaptable for the big data traffic, to improve the security of wireless networks. Specifically, a big-data aided hybrid relay selection scheme is designed and analyzed to enhance physical layer security. First, considering the ideal situation that an eavesdropper’s CSI (Channel State Information) is known to the legal nodes, we propose an optimal hybrid relay selection scheme consisting of the optimal mode selection scheme and the optimal relay selection scheme. In this case, we analyze the upper bound of an eavesdropper’s capacity in FD (Full-Duplex) mode and the secrecy outage probabilities of the optimal HD (Half-Duplex), FD, and hybrid relay selection schemes. Through the analysis of data, it is clear that the mode selection is decided by the self-interference of the FD technique. However, the instantaneous CSI of an eavesdropper is difficult to obtain due to the passive characteristic of eavesdroppers in practice. Therefore, a more practical hybrid relay selection scheme with only the channel distribution information of an eavesdropper is further studied, where a weighting factor is employed to guarantee that the hybrid mode is no worse than either the FD mode or HD mode when the self-interference grows. Finally, the simulation results show the improved security of our proposed scheme.","Title: Robust Relay in Narrow-Band Communications for Ubiquitous IoT Access.\nYear: 2017\n\nAbstract: We propose a robustwireless relay scheme in narrow-band communications for IoT access, whichmatches the typical features of IoT often carrying relatively low data rate with limited bandwidth. This framework is towards offering robustness in QoS guarantees with emphases on security and/or reliability, and we use the security-assured network as the typical scenario. In particular, we consider a dual-hop relay network including a transmitter, a receiver, an amplify-and-forward (AF) untrusted relay, and a jamming node. The jamming node is treated as a helper. Specifically, the jammer broadcasts artificial noise (AN), which in fact pollutes both the untrusted relay and the destination node's signals. However, we show that such AN can be effectively mitigated after the destination node obtains the forwarded signal from the relay, while the untrusted relay node cannot do so. The core idea for robustness assurance is to exploit higher signal dimensions at the receiver over the untrusted relay node. Simulations and analyses are also conducted to demonstrate that our proposed scheme can make the performance at the untrusted relay an interferencelimited manner while completely removing the interferences at the receiver, therefore corroborating our claim in robustness in terms of security and reliability.","Title: Robust, Efficient Depth Reconstruction With Hierarchical Confidence-Based Matching.\nYear: 2017\n\nAbstract: In recent years, taking photos and capturing videos with mobile devices have become increasingly popular. Emerging applications based on the depth reconstruction technique have been developed, such as Google lens blur. However, depth reconstruction is difficult due to occlusions, non-diffuse surfaces, repetitive patterns, and textureless surfaces, and it has become more difficult due to the unstable image quality and uncontrolled scene condition in the mobile setting. In this paper, we present a novel hierarchical framework with multi-view confidence-based matching for robust, efficient depth reconstruction in uncontrolled scenes. Particularly, the proposed framework combines local cost aggregation with global cost optimization in a complementary manner that increases efficiency and accuracy. A depth map is efficiently obtained in a coarse-to-fine manner by using an image pyramid. Moreover, confidence maps are computed to robustly fuse multi-view matching cues, and to constrain the stereo matching on a finer scale. The proposed framework has been evaluated with challenging indoor and outdoor scenes, and has achieved robust and efficient depth reconstruction.","Title: Primary Secure Communication With The Cooperation Of Energy Harvesting Secondary System\nYear: 2016\n\nAbstract: Aiming at providing secure provisioning for the primary system, in this paper, we propose an energy harvesting based cooperative communication (EHCC) scheme which will protect the primary confidential message from eavesdropping under the constraint of the secondary quality-of-service (QoS) requirement. To do so, the secondary receiver (SR) firstly transmits jamming signal to protect the primary transmission and then, the secondary transmit (ST) harvests part of the received signals and forwards the remaining signals to the primary receiver (PR) concurrently with the secondary transmission. In our proposed scheme, radio-frequency energy harvesting will improve ST's maximum transmit power and the jamming interference at SR can be directly cancelled as SR has transmitted it. Then, we try to allocate the transmit power and design energy harvesting parameters in such a way that the secrecy capacity of the primary system is maximized under the constraint of the secondary QoS requirement. In addition, an iterative algorithm is proposed to solve this non-convex problem. Moreover, we also analyze the primary secrecy capacities and allocate the resource for the asymptotic scenarios. Simulation results demonstrate the performance superiority of our proposed scheme over the conventional cooperative secure communication scheme in terms of the primary secrecy capacity.","Title: Secure And Energy Efficient Transmission In Multiuser Uplink Wireless Networks\nYear: 2016\n\nAbstract: Security and energy efficiency are two critical metrics in many multiuser networks (e.g. M2M networks, sensor networks and ad hoc networks). In this paper, we try to maximize secure energy efficiency (SEE) by allocating power for those User Equipments (UEs) meeting the security transmission requirements, where SEE is defined as the ratio of the total secrecy throughput to the total transmission power in the whole network. Concretely, we propose an efficient algorithm which uses the parametric programming and Difference of Convex (DC) function to solve the optimization problem (i.e. maximize secure energy efficiency). Finally, we compare the secure energy efficiency of our scheme with that of fixed power allocation schemes and show the results through simulations at different system conditions.","Title: Two-path successive relaying and jamming for securing the primary system\nYear: 2016\n\nAbstract: To guarantee secure communication of the primary system and efficiently utilize the licensed spectrum, in this paper, we propose a two-path successive relaying and jamming based cooperative transmission (TSRJC) scheme. In TSRJC scheme, two secondary users (SU) successively relay the primary message and jam the primary eavesdropper to confirm secure and reliable transmission of the primary system during the first stage. During the second stage, the secondary system will be allowed to access the licensed spectrum for the secondary transmission as a reward. To maximize the secondary transmission, a suboptimal algorithm is proposed to allocate the relaying and jamming power. In addition, the closed-form expressions of both SU's relaying and jamming power and jamming power beamforming vector are derived. Simulation results demonstrate the superior performance of our developed scheme over conventional secure communication scheme in terms of primary users' (PU) secure outage probability and SUs' average transmission rate.","Title: Multi-resolution-based road state estimation\nYear: 2016\n\nAbstract: In this paper, we suggest an accessible and effective approach to the urban road state estimation. The main technical contribution of the proposed method is a novel feature extraction on the basis of the multi-resolution, along with support vector machine for classification. Experimental tests have been carried out to validate our proposed approach which can estimate road state in the sample of a hundred of city road images computational efficiently and effectively.","Title: One sample based feature learning for vehicle identification\nYear: 2016\n\nAbstract: Vehicle identification is one of the frequently studied problems in video surveillance. Commonly, identifying an unknown vehicle object requires a large amount of training instances. Unfortunately, in the large parking scenario, the cost may be prohibitively expensive because of the finitely waiting time from the car owners. In this paper, we show that it is possible to identify a registered vehicle using a single training example. The key insight is that, the human visually representative properties, such as overall appearance and local texture, are described using colors and histogram of oriented gradient (HOG). They are firstly extracted from each patch to form the fundamental representation. After that, the well developed locality-constrained linear coding (LLC) technique is employed to learn a more informative representation. Next, with nearest neighbors (NN) servers as the main classifier, the classical genetic algorithm (GA) is utilized to decide the most informative patches so that the minimum mis-identified error is achieved. The proposed approach is experimentally demonstrated and evaluated on the open “Dana36” data set using vehicle images that are taken under an approximate camera pose. Good improvements are obtained with respect to the strategies that do not use LLC encoded features and selectively combined patches.","Title: Image segmentation based on 2D OTSU and simplified swarm optimization\nYear: 2016\n\nAbstract: Image segmentation is a classic problem and basic research area in image processing. It can provide pre-detect information for subsequent image processing and classification. 2D Otsu method is a widely used non-parametric method to detect the threshold of image. In this paper, we employ the simplified swarm optimization (SSO) as a swarm-intelligent optimization method to search the threshold value based on 2D Otsu method. Experimental result has shown that the proposed method could consume less computation time of 2D Otsu method and achieve the optimal value.","Title: ESPS scheme for two-tier interference suppression in a heterogeneous network with cooperative femtocells\nYear: 2015\n\nAbstract: The coexistence of a macrocell and a number of femtocells often leads to a two‐tier\n heterogeneous network, where the co‐tier interference (CotIN) and cross‐tier interference\n (CrotIN) both degrade users' quality of service. In order to suppress these interferences,\n we propose a precoding scheme in a heterogeneous network with cooperative femtocells,\n called CotIN elimination and CrotIN suppression with precoding criterion selection\n (ESPS) scheme. In this scheme, we first eliminate the CotINs of each user by applying\n the QR decomposition to channel matrix. Then the CrotINs of macrocell users and femtocell\n users are suppressed via the macrocell base station (MBS) and femtocell access points\n (FAPs) with precoding criterion selection, respectively. By using the ESPS scheme,\n spatial resources can be efficiently exploited. In addition, our ESPS scheme requires\n little information exchange between MBS and FAPs without iteration and thus significantly\n reduces the implementation complexity. Furthermore, the robustness is increased through\n introducing the information of channel uncertainty into the ESPS when channel estimation\n or quantization error exists. The performance analysis for the ESPS demonstrates that\n the ESPS is practical in the heterogeneous networks. Finally, simulation results show\n that the ESPS can decrease users' bit error rates and increase their transmission\n rates. Copyright © 2015 John Wiley & Sons, Ltd.","Title: Efficient incremental dynamic link prediction algorithms in social network.\nYear: 2017\n\nAbstract: To enhance customers’ loyalty and experience, link prediction in social networks can help service providers to predict the friendship between users in the future, according to the network structure and personal information. However, most of prior studies consider link prediction in the static scenario while ignoring that the social network generally is updated over time. In this paper, to address this problem, we design two efficient incremental dynamic algorithms that can predict the relationship between users according to the updated social network structure. The first one, instead of using classic prediction index, creates a latent space for each node in the network, and adopts the incremental calculation to predict the future links according to the position of each node in the latent space. The second one is a dynamic improved algorithm based on the resource allocation index, which only recalculates updated part of the social network structure instead of the whole social network. Extensive experiments show that our first algorithm has high prediction accuracy while the second algorithm incurs low running time cost at the expense of less prediction accuracy.","Title: Exploring the Difficulties African-American Middle School Girls Face Enacting Computational Algorithmic Thinking over three Years while Designing Games for Social Change.\nYear: 2017\n\nAbstract: Computational algorithmic thinking (CAT) is the ability to design, implement, and assess the implementation of algorithms to solve a range of problems. It involves identifying and understanding a problem, articulating an algorithm or set of algorithms in the form of a solution to the problem, implementing that solution in such a way that the solution solves the problem, and evaluating the solution based on some set of criteria. CAT is an important scaffolded on-ramp as students develop more advanced computational thinking capabilities and apply computational thinking to solve problems that are more constrained and require greater expertise. Supporting Computational Algorithmic Thinking (SCAT) is both a longitudinal between-subjects research project and a free enrichment program supporting and guiding African-American middle school girls over three years as they iteratively design a set of complex games for social change. This article explores Scholars' reflections about the difficulties they faced while using CAT capabilities as they engaged in collaborative game design for social change over those three years. We particularly focus on how these difficulties changed over the course of three years as well as new difficulties that emerged from year to year as Scholars become more expert game designers and computational algorithmic thinkers.","Title: Interference-constrained routing over P2P-share enabled multi-hop D2D networks.\nYear: 2017\n\nAbstract: The exponentially-increasing demands on ubiquitous information exchange have inspired wide research interests and efforts on the 5th Generation (5G) of mobile communications system. Among diverse cutting-edge revolutionary technologies towards 5G networks, device-to-device (D2D) networks, where device nodes can communicate with each other by reusing the cellular network’s spectrum in an underlay fashion. We in this paper propose the interference-constrained routing schemes over peer-to-peer (P2P) share enabled multi-hop D2D networks, where multiple D2D subscribers attempt to download the common data from multiple distributed D2D servers. In particular, we aim at optimizing the average download rate over subscribers subject to the interference constraint for cellular network’s spectrum. We first focus on a typical case with two subscribers, two file servers, and two cellular users. We propose a Routing scheme with Direct P2P-Share (R-DPS), which allows subscribers to distribute their received data to each other via a detoured route. To offer better performances, we develop an improved Routing scheme, named Coverage-based P2P-Share (R-CPS). The R-CPS scheme can effectively make use of the broadcast nature of wireless channels to assure that each selected route can cover the other subscriber, rather than directly pass through them in the R-DPS scheme. We further study the generalized case where the number of subscribers, servers, and cellular users can be arbitrary. Particularly, we propose a Routing scheme with Location-Aware P2P-Share (R-LPS) mechanism, the core idea of which is to find a route passing by or directly through other subscribers. Simulation evaluations demonstrate that our proposed R-DPS and R-CPS schemes for the two-subscriber case and the R-LPS scheme for the generalized case all have the capability to effectively improve the data download rate as compared to the approach without enabling P2P support.","Title: Ica-Sbdc: A Channel Estimation And Identification Mechanism For Miso-Ofdm Systems Under Pilot Spoofing Attack\nYear: 2017\n\nAbstract: Pilot spoofing attack is a serious threat to time-division duplex (TDD) orthogonal frequency division multiplexing (TDD-OFDM) system. By employing identical pilot tones as a legitimate receiver, an adversary can contaminate the uplink channel estimation between a transceiver pair. To solve this problem, we in this paper propose an independent component analysis (ICA) based channel estimation and identification mechanism with a subcarrier-block discriminating coding (SBDC) technique (ICA-SBDC). Firstly, a receiver randomizes the values of its pilot tones to avoid contamination, which however incurs pilot jamming attack. A minor-component-based detector (MCD) is devised to detect the attack efficiently. Secondly, the transmitter exploits the fourth-order statistical information of received signals to extract a linear-mixing channel. We can prove that given previously used legitimate pilots, both legitimate and attack sub-channels can be recovered from the obtained channel. Finally, the receiver maps its utilized pilots into various uplink transmission strategies on subcarrier-blocks which can be ultimately identified by the transmitter in a jamming environment. The mapping therein is formulated via a public-known codebook with discriminating algebraic property and the identification is achieved by decoding the codebook according to the results of MCD-based detection for each subcarrier-block. Simulation results verify the effectiveness of our proposed mechanism.","Title: Combat Eavesdropping By Full-Duplex Technology And Signal Transformation In Non-Orthogonal Multiple Access Transmission\nYear: 2017\n\nAbstract: Non-orthogonal multiple access (NOMA) is an important multiple access mode in 5G. Nevertheless, eavesdropping may appear between the users in NOMA. In this case, physical layer security schemes can be introduced to combat eavesdropping. Different from the existing schemes, eavesdropping suppression in NOMA should be based on several rules: (i) successive interference cancellation (SIC) should be normally operated; (ii) each user can not attain others' privacy information; (iii) each adopted scheme had better not to depend on the spatial disparity between channels (since the channels may have the strong spatial similarity). Therefore, we propose a novel scheme to adapt to these rules. In our scheme, the original signals of users are separately transformed into the transmitted signals by a well-designed angle conversion method, and the principles of these variations for diverse users are different. Furthermore, an auxiliary mechanism with full-duplex technology is devised to guarantee the users to safely learn the principles, respectively. Through this scheme, each user can deduce other users' transmitted signals for SIC, while the original signals are difficult to be determined from transmitted signals. Hence, our scheme can effectively improve security.","Title: Age Estimation by Refining Label Distribution in Deep CNN.\nYear: 2017\n\nAbstract: This paper proposes an age estimation algorithm by refining the label distribution in a deep learning framework. There are two tasks during the training period of our algorithm. The first one finds the optimal parameters of supervised deep CNN by given the label distribution of the training sample as the ground truth, while the second one estimates the variances of label distribution to fit the output of the CNN. These two tasks are performed alternatively and both of them are treated as the supervised learning tasks. The AlexNet and ResNet-50 architectures are adopted as the classifiers and the Gaussian form of the label distribution is assumed. Experiments show that the accuracy of age estimation can be improved by refining label distribution.","Title: Passenger Travel Path Estimation Algorithm Based on High Accuracy Location Data\nYear: 2017\n\nAbstract: With the rapid development of rail transit, urban rail transit network is increasingly becoming complex due to the intersection of the different operating lines. In order to guarantee the convenience of passenger's travel, most domestic the existing metro system passengers' records are only retrieved at entry and exit points. With such a system, it is difficult to track the passengers' complete path since they usually go through different lines before arriving their final destinations, so it is difficult for the different subway operators to fare clearing. To determine the complete travel path of passengers in a metro system, path estimation methods based on shortest path algorithm, Logit technique, and the normal function model have been proposed. These methods basically depend on passenger surveys, low data samples, and long adjustment periods for model parameters which limit their accuracy in practical application. Therefore, in order to get the complete path of passengers for support subway operators to fare clearing, this paper presents a novel passenger travel path estimation algorithm based on indoor high precision positioning data, combined with high-precision indoor positioning technology. And revert the passenger's track of each site, through the whole network of more than 60% of the user's actual travel trajectory to obtain the passenger's selection probability of travel path. And this suggests that the proposed model may provide data support for urban rail transit passenger clearance in the metro system.","Title: Improved Uneven Cluster-Based routing protocol based on CRT algorithm.\nYear: 2017\n\nAbstract: Energy-Efficient Uneven Clustering (EEUC) protocol is applied to low-redundancy Wireless Sensor Network (WSN), the uneven consumption of sensor node energy leads to nodes' early death which will seriously affect the network quality. This paper proposes the Chinese Remainder Theorem (CRT) division algorithm for EEUC Energy-Efficient Uneven Clustering routing protocol optimization. The nodes split the packets before forwarding and balance the energy consumption of the nodes forward packets which results in alleviating hot problems of wireless sensor networks. We also add energy and distance parameters to the threshold function in the cluster heads selection mechanism, and optimize the cluster semidiameter to make the cluster head election distribution more reasonable which will help to optimize the network energy consumption. The result of simulation indicates that the algorithm we propose can make energy consumption of lower redundant sensor network nodes more balanced and delay the first death time of node as well as prolong the network life time effectively.","Title: Localization Research about the Node without Identifies for the Sparse WSN Environment.\nYear: 2017\n\nAbstract: For the problem of nodes without identifies and quantity in the environment of wireless sensor network, a new route model of mobile anchor node is provided. The model composed of the one heavy path and the three heavy path. The paper first is to obtain the optimal path through traversing all of the fixed virtual anchor nodes using the model of TSP, and then enters the three heavy path while anchor node sense the unknown nodes in the one heavy path. After have received the three numbers of RSSI data, the anchor node returned to one heavy path. Finally, the location and numbers of the unknown nodes will be obtained after generalize all of the nodes using iterative methods. The experimental results show that, in the case of the unknown nodes distributed sparse, the proposed path model can reduce the redundant path and the moving time, which reached the goal of the high precision of location.","Title: Rural Building Detection in High-Resolution Imagery Based on a Two-Stage CNN Model.\nYear: 2017\n\nAbstract: High-level feature extraction and hierarchical feature representation of image objects with a convolutional neural network (CNN) can overcome the limitations of the traditional building detection models using middle/low-level features extracted from a complex background. Aiming at the drawbacks of manual village location, high cost, and the limited accuracy of building detection in the existing ru...","Title: Development and Evaluation of A Novel and Cost-Effective Approach for Low-Cost NO2 Sensor Drift Correction.\nYear: 2017\n\nAbstract: Emerging low-cost gas sensor technologies have received increasing attention in recent years for air quality measurements due to their small size and convenient deployment. However, in the diverse applications these sensors face many technological challenges, including sensor drift over long-term deployment that cannot be easily addressed using mathematical correction algorithms or machine learning methods. This study aims to develop a novel approach to auto-correct the drift of commonly used electrochemical nitrogen dioxide (NO2) sensor with comprehensive evaluation of its application. The impact of environmental factors on the NO2 electrochemical sensor in low-ppb concentration level measurement was evaluated in laboratory and the temperature and relative humidity correction algorithm was evaluated. An automated zeroing protocol was developed and assessed using a chemical absorbent to remove NO2 as a means to perform zero correction in varying ambient conditions. The sensor system was operated in three different environments in which data were compared to a reference NO2 analyzer. The results showed that the zero-calibration protocol effectively corrected the observed drift of the sensor output. This technique offers the ability to enhance the performance of low-cost sensor based systems and these findings suggest extension of the approach to improve data quality from sensors measuring other gaseous pollutants in urban air.","Title: Dense RGB-D semantic mapping with Pixel-Voxel neural network.\nYear: 2018\n\nAbstract: In this paper, a novel Pixel-Voxel network is proposed for dense 3D semantic mapping, which can perform dense 3D mapping while simultaneously recognizing and labelling the semantic category each point in the 3D map. In our approach, we fully leverage the advantages of different modalities. That is, the PixelNet can learn the high-level contextual information from 2D RGB images, and the VoxelNet can learn 3D geometrical shapes from the 3D point cloud. Unlike the existing architecture that fuses score maps from different modalities with equal weights, we propose a softmax weighted fusion stack that adaptively learns the varying contributions of PixelNet and VoxelNet and fuses the score maps according to their respective confidence levels. Our approach achieved competitive results on both the SUN RGB-D and NYU V2 benchmarks, while the runtime of the proposed system is boosted to around 13 Hz, enabling near-real-time performance using an i7 eight-cores PC with a single Titan X GPU.","Title: Security Provisioning for MISO Vehicular Relay Networks via Cooperative Jamming and Signal Superposition.\nYear: 2017\n\nAbstract: We study the cooperative secure transmissions in (multiple-input signal-output) MISO vehicular relay networks where the infrastructure node with multiple antennas sends two confidential messages to two legitimate vehicles with only one antenna, respectively. By exploiting the signal superposition and cooperative jamming techniques, the legitimate vehicle near the infrastructure node directly decod...","Title: Design for NOMA: Combat Eavesdropping and Improve Spectral Efficiency in the Two-User Relay Network.\nYear: 2017\n\nAbstract: Non-orthogonal multiple access (NOMA) is important in 5G, and the users served in NOMA are often paired to avoid the excessive interference. However, for a two-user network, if the channel condition of one user is serious, this network may require the other user to relay this user's signals. In this case, the demands of these users are possibly different. Specifically, the relay user may want the node to increase the spectral efficiency for compensating the cost of relay. On the other hand, because privacy information may be contained in signals, the indirect communication user may primarily focus on his or her information security. Therefore, we propose a novel physical layer scheme to satisfy these demands. Different from the existing relay schemes in NOMA, our scheme has the following characteristics: (i) through power allocation, the relay user can extract his or her signals with spectral efficiency improvement; (ii) through a signal-level method, the relay user can forward the indirect communication user's signals, but he or she is difficult to learn the privacy information in these signals; (iii) through a mechanism, the indirect communication user can attain his or her privacy information. Our scheme is able to support the relay user's demand, and this eavesdropping suppression in our scheme doe not depend on the complicated encryption techniques and positive secrecy rate.","Title: An Artificial Noise-Based Security Scheme for Interference Alignment-Based Wireless Networks.\nYear: 2017\n\nAbstract: The security of the interference alignment (IA)based networks is of uttermost importance for the application of interference alignment in multi-user networks. Several recent works have utilize the physical layer security schemes including artificial noise (AN) and friendly jamming etc. to reduce the eavesdropping capabilities of an outside eavesdropper. In this paper, we propose a novel AN-based anti-eavesdropping scheme in IA-based networks where the AN and the interferences are aligned into two different subspaces at the desired receiver. This results in more confusion to the eavesdropper and an enhancement of the desired signal simultaneously. The simulations testify this observation.","Title: Person Re-id by Incorporating PCA Loss in CNN.\nYear: 2018\n\nAbstract: This paper proposes an algorithm, particularly a loss function and its end to end learning manner, for person re-identification task. The main idea is to take full advantage of the labels in a batch during training, and to employ PCA to extract discriminative features. Deriving from the classic eigenvalue computation problem in PCA, our method incorporates an extra term in loss function with the purpose of minimizing those relative large eigenvalues. And the derivative with respect to the designed loss can be back-propagated in deep network by stochastic gradient descent (SGD). Experiments show the effectiveness of our algorithm on several re-id datasets.","Title: Multisensor Online Transfer Learning for 3D LiDAR-based Human Classification with a Mobile Robot.\nYear: 2018\n\nAbstract: Human detection and tracking is an essential task for service robots, where the combined use of multiple sensors has potential advantages that are yet to be fully exploited. In this paper, we introduce a framework allowing a robot to learn a new 3D LiDAR-based human classifier from other sensors over time, taking advantage of a multisensor tracking system. The main innovation is the use of different detectors for existing sensors (i.e. RGB-D camera, 2D LiDAR) to train, online, a new 3D LiDAR-based human classifier based on a new “trajectory probability”. Our framework uses this probability to check whether new detection belongs to a human trajectory, estimated by different sensors and/or detectors, and to learn a human classifier in a semi-supervised fashion. The framework has been implemented and tested on a real-world dataset collected by a mobile robot. We present experiments illustrating that our system is able to effectively learn from different sensors and from the environment, and that the performance of the 3D LiDAR-based human classification improves with the number of sensors/detectors used.","Title: Towards win-win: weighted-Voronoi-diagram based channel quantization for security enhancement in downlink cloud-RAN with limited CSI feedback.\nYear: 2017\n\nAbstract: Physical layer (PHY) security is recently proved to enable improving the security of wireless communication networks. In downlink frequency division duplex (FDD) cloud radio access network (C-RAN), the performance of PHY security highly relies on the channel state information (CSI) which is usually acquired through the codebook-quantization-based technique at the transceiver. However, the conventional quantization method aggravates the leakage of privacy information in C-RAN under the eavesdropping environment. In this paper, a novel channel quantization method is investigated to improve the secrecy-rate performance of C-RAN by exploiting the high-dimension space geometry. Based on this method, it is proved that when the statistical distribution of the channel matrices of both the legitimate user and the eavesdropper is exploited, a win-win situation can be created where secrecy-rate gains are improved without sacrificing beamforming gains from the point of view of ergodic rate. Particularly, a secrecy-oriented criterion is devised to implement the proposed method for generating codebooks. Then a weighted Voronoi diagram (WVD) is formulated on the complex Grassmann manifold and finally, a vector quantization based algorithm is proposed to build up novel quantization codebooks iteratively. Simulation results further validate the superiority of our proposed codebooks over conventional codebooks in C-RAN systems.","Title: Facial age estimation through self-paced learning\nYear: 2017\n\nAbstract: This paper proposes an age estimation algorithm in Self-Paced Learning (SPL) framework. Facial samples in the training set inherently include both easy and complex images, which is caused by both the characteristic of age and the variation of pose or expression. Furthermore, by randomly hiding patches in face region, data with different difficulty levels can be gradually used by SPL, in which Convolution Neural Network (CNN) is trained to give the estimation. Alternative Optimization Strategy (AVO), for the weight of CNN and the latent weight in SPL regularizer, is adopted in SPL framework. Experiments show that the proposed algorithm is able to give an accurate results especially under pose and expression variation.","Title: Impact Analysis of Temperature and Humidity Conditions on Electrochemical Sensor Response in Ambient Air Quality Monitoring.\nYear: 2018\n\nAbstract: The increasing applications of low-cost air sensors promises more convenient and cost-effective systems for air monitoring in many places and under many conditions. However, the data quality from such systems has not been fully characterized and may not meet user expectations in research and regulatory uses, or for use in citizen science. In our study, electrochemical sensors (Alphasense B4 series) for carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and oxidants (O-x) were evaluated under controlled laboratory conditions to identify the influencing factors and quantify their relation with sensor outputs. Based on the laboratory tests, we developed different correction methods to compensate for the impact of ambient conditions. Further, the sensors were assembled into a monitoring system and tested in ambient conditions in Hong Kong side-by-side with regulatory reference monitors, and data from these tests were used to evaluate the performance of the models, to refine them, and validate their applicability in variable ambient conditions in the field. The more comprehensive correction models demonstrated enhanced performance when compared with uncorrected data. One over-arching observation of this study is that the low-cost sensors may promise excellent sensitivity and performance, but it is essential for users to understand and account for several key factors that may strongly affect the nature of sensor data. In this paper, we also evaluated factors of multi-month stability, temperature, and humidity, and considered the interaction of oxidant gases NO2 and ozone on a newly introduced oxidant sensor.","Title: Learning Monocular Visual Odometry With Dense 3d Mapping From Dense 3d Flow\nYear: 2018\n\nAbstract: This paper introduces a fully deep learning approach to monocular SLAM, which can perform simultaneous localization using a neural network for learning visual odometry (L-VO) and dense 3D mapping. Dense 2D flow and a depth image are generated from monocular images by sub-networks, which are then used by a 3D flow associated layer in the L-VO network to generate dense 3D flow. Given this 3D flow, the dual-stream L-VO network can then predict the 6DOF relative pose and furthermore reconstruct the vehicle trajectory. In order to learn the correlation between motion directions, the Bivariate Gaussian modeling is employed in the loss function. The L-VO network achieves an overall performance of 2:68% for average translational error and 0.0143 degrees/m for average rotational error on the KITTI odometry benchmark. Moreover, the learned depth is leveraged to generate a dense 3D map. As a result, an entire visual SLAM system, that is, learning monocular odometry combined with dense 3D mapping, is achieved.","Title: Age Estimation via Pose-Invariant 3D Face Alignment Feature in 3 Streams of CNN.\nYear: 2017\n\nAbstract: This paper proposes an algorithm for age estimation intentionally considering the pose variation and local deformation of faces. Pose-invariant patches are extracted in face region, and they are located from the landmarks' neighborhood in 2D image coordinate. The landmarks can be regarded as the projections of the points on 3D face model, and the projection parameters are estimated by Convolution Neural Network (CNN). Two different structures of CNN are designed for age estimation task. One way is to stack individual patch in the spatial domain, and the stacked image is given to a CNN to make the estimation. The second is to design CNN for each particular patch and CNNs for different patches do not share weights. Together with another CNN trained on the original face region, the three streams for age estimation are combined by late fusion of the output layer. Experiments show that the proposed scheme outperforms other state-of-the-art methods.","Title: An Approach for Setting Parameters for Two-Degree-of-Freedom PID Controllers.\nYear: 2018\n\nAbstract: In this paper, a new tuning method is proposed, based on the desired dynamics equation (DDE) and the generalized frequency method (GFM), for a two-degree-of-freedom proportional-integral-derivative (PID) controller. The DDE method builds a quantitative relationship between the performance and the two-degree-of-freedom PID controller parameters and guarantees the desired dynamic, but it cannot guarantee the stability margin. So, we have developed the proposed tuning method, which guarantees not only the desired dynamic but also the stability margin. Based on the DDE and the GFM, several simple formulas are deduced to calculate directly the controller parameters. In addition, it performs almost no overshooting setpoint response. Compared with Panagopoulos' method, the proposed methodology is proven to be effective.","Title: Scale-Invariant Wave Kernel Signature for Non-Rigid 3D Shape Retrieval\nYear: 2018\n\nAbstract: The number of non-rigid 3D shapes increases steadily in various areas. It is imperative to develop efficient retrieval system for 3D non-rigid shapes. The wave kernel signature was introduced as an intrinsic local shape descriptor based on the wave function, which represents the average probability of a quantum mechanical particle at a specific location. In this paper, we develop a scale-invariant wave kernel signature normalizing with eigenvalues of the Laplace-Beltrami operator. The proposed descriptor is useful in coping with 3D shapes which have undergone scale transformation. Experimental results on public benchmarks show that our method outperforms the method based on the wave kernel signature for non-rigid 3D shape retrieval.","Title: Security-Aware Waveform and Artificial Noise Design for Time-Reversal-Based Transmission.\nYear: 2018\n\nAbstract: Among the plenty of studies on physical layer security, multi-antenna signal processing and nodes cooperation are two widely adopted techniques. However, in practical systems there are many single-antenna devices that do not support cooperative transmission either. To guarantee the information security in this scenario, we propose a novel transmission strategy that exploits the temporal characteri...","Title: Fountain-Coding Aided Symmetrical Encryption for Secure Wireless Transmission.\nYear: 2017\n\nAbstract: It is difficult to ensure secure transmissions in wireless networks because of the openness of radio signal. In this paper, a fountain-coding aided symmetrical encryption scheme is proposed to deal with this problem. In the proposed scheme, all source packets are first encrypted with a secret key. Then, all encrypted source packets are encoded with fountain code and next transmitted on wireless channels. Finally, the secret key is encrypted with all the fountain-coded packets the legitimate receiver has received for sharing the secret key between the legitimate users. Due to the independent fading characteristic between the legitimate channel and the wiretap channel, if the eavesdropper fails to correctly receive some fountain-coded packets the legitimate receiver receives, the wireless transmission can be secured under appropriate conditions. Compared with the counterparts, the proposed scheme achieves lower intercept probability of the eavesdropper with little receiver feedback burden under appropriate conditions.","Title: Traffic-Driven Intrusion Detection For Massive Mtc Towards 5g Networks\nYear: 2018\n\nAbstract: Massive machine type communications (MTC) have been proposed to be one of the major scenarios in 5G networks, which play the role of supporting future IoT towards ubiquitous information acquisition and exchange. Due to the requirement on low-cost devices, the requirement on anti-intrusion security calls for dedicated research efforts. To meet the MTC security requirements, some security enhancement techniques have been proposed, i.e., the evolved packet system-authentication and key agreement (EPS-AKA). However, with the growth of malicious devices's computing capability and attack ability, security protocol applied on high layer faces more threats and challenges, and even become much less effective. In this paper, we take the essential nature of traffic characteristics into consideration and establish the framework of intrusion detection for massive MTC networks. Then, we propose a traffic-driven intrusion detection scheme, the innovations of which contain two folds: 1) effective estimation of traffic arrival process based on Markovian chain and air-interface access statuses; 2) low-latency yet accurate decision criterion. We also conduct abundant simulations to evaluate our scheme's performances. Simulation results demonstrate that our scheme can well track the arrival process with high accuracy, outperforming the baseline schemes in terms of the not only the detection probability but also the detection time.","Title: Efficient 3D Object Retrieval Based on Compact Views and Hamming Embedding.\nYear: 2018\n\nAbstract: View-based 3-D object retrieval techniques have been increasingly important in various applications of computer vision. In this paper, we present a novel framework for view-based 3-D object retrieval. First, we exclude the background of views to avoid the disturbance of background noise. Then for these views, we extract the domain-size pooled SIFT descriptor features and encode them using approximate K-means algorithm. After quantizing each object with the approximate near neighbor, the hamming embedding is applied to refine the descriptors by adding binary signatures. Finally, we use the hamming matching to measure the similarity between two 3-D objects. A large number of experiments are performed on the ETH-80 benchmark. Compared with the state-of-art methods, the proposed method is demonstrated to be effective and robust.","Title: Recurrent-Octomap: Learning State-Based Map Refinement For Long-Term Semantic Mapping With 3-D-Lidar Data\nYear: 2018\n\nAbstract: This letter presents a novel semantic mapping approach, Recurrent-OctoMap, learned from long-term three-dimensional (3-D) Lidar data. Most existing semantic mapping approaches focus on improving semantic understanding of single frames, rather than 3-D refinement of semantic maps (i.e. fusing semantic observations). The most widely used approach for the 3-D semantic map refinement is \"Bayes update,\" which fuses the consecutive predictive probabilities following a Markov-chain model. Instead, we propose a learning approach to fuse the semantic features, rather than simply fusing predictions from a classifier. In our approach, we represent and maintain our 3-D map as an OctoMap, and model each cell as a recurrent neural network, to obtain a Recurrent-OctoMap. In this case, the semantic mapping process can he formulated as a sequence-to-sequence encoding-decoding problem. Moreover, in order to extend the duration of observations in our Recurrent-OctoMap, we developed a robust 3-D localization and mapping system for successively mapping a dynamic environment using more than two weeks of data, and the system can he trained and deployed with arbitrary memory length. We validate our approach on the ETH long-term 3-D Lidar dataset. The experimental results show that our proposed approach outperforms the conventional \"Bayes update\" approach.","Title: Voltage And Fuel Utilization Control For Solid Oxide Fuel Cells With Combined L1 Adaptive - Predictive Control Strategy\nYear: 2018\n\nAbstract: Output voltage and fuel utilization control of Solid Oxide Fuel Cells (SOFCs) is challenging due to large inertia, nonlinearity and safety related constraints associated with the system. The academic community seeks to solve this problem by resorting to Model Predictive Control (MPC), which is convenient to formulate the difficulties in its receding horizon optimization problem. However, the high demand of MPC for online computation limits its application in practical engineering. In this paper, a combined control strategy with MPC and L1 adaptive control (L1AC) is proposed to handle the control difficulties in SOFC with acceptable computation cost. The L1AC compensates the system nonlinearity and disturbances as lumped uncertainty, with guaranteed performance and then provide an ideal linear model for MPC. Then MPC provides optimal control signal with all the system constraints satisfied. The simulation result shows the proposed control system has good performance of regulation and disturbance rejection. The computation time for MPC is much less than the sampling time and is capable of practical application.","Title: Secure Cooperative Communication With Nondedicated Relays.\nYear: 2018\n\nAbstract: The security issue is considered for a cooperative communication system with multiple nondedicated relays, which have their own information to transmit. Distributed spatial modulation (DSM) is a promising technique for nondedicated relay networks. However, any receiver in the relays' coverage can decode the source information by examining the status of the relays in conventional DSM systems. To pr...","Title: Outlier Data Treatment Methods Toward Smart Grid Applications.\nYear: 2018\n\nAbstract: In a smart grid environment, advanced metering infrastructure (AMI) and intelligent sensors have been deployed extensively. As a result, large-scale and fine-grained smart grid data are more convenient to be collected, in which outliers exist pervasively, caused by system failures, environmental effects, and human interventions. Outlier deletion is always implemented in data preprocessing for improving data quality. However, due to the fact that real records that reflect rare and unusual patterns are also recognized as outliers, outlier mining is necessary to be carried out with the aim of discovering knowledge on abnormal patterns in power generation, transmission, distribution, transformation, and consumption. To the best of our knowledge, a comprehensive and systematic review of outlier data treatment methods is still lacked in the smart grid environment. We, in this paper, aim at presenting the review of outlier data treatment methods toward smart grid applications and categorize them into outlier rejection and outlier mining groups. Since we do this survey from the perspective of data-driven analytics and data mining methods, information security technologies are barely discussed in this paper. Based on a general overview of outlier data treatment methods, we make the contribution of providing the application scenarios of outlier rejection and outlier mining in the smart grid environment. With the construction of smart grid throughout the world, dealing with outlier data has become more crucial for the security and reliability of power system operation. Therefore, we also discuss some future challenges of outlier data treatment toward smart energy management.","Title: Ecg Delineation With Randomly Selected Wavelet Feature And Random Forest Classifier\nYear: 2018\n\nAbstract: Objective: Detection of Electrocardiogram (ECG) characteristic points can provide critical diagnostic information about heart diseases. We proposed a novel feature extraction and machine learning scheme for automatic detection of ECG characteristic points. Methods: A new feature, termed as randomly selected wavelet transform (RSWT) feature, was devised to represent ECG characteristic points. A random forest classifier was adapted to infer the characteristic points position with high sensitivity and precision. Results: Compared with other state-of-the-art algorithms' testing results on QT database, our detection results of RSWT scheme showed comparable performance (similar sensitivity, precision, and detection error for each characteristic point). RSWT testing on MIT-BIH database also demonstrated promising cross-database performance. Conclusion: A novel RSWT feature and a new detection scheme was fabricated for ECG characteristic points. The RSWT demonstrated a robust and trustworthy feature for representing ECG morphologies. Significance: With the effectiveness of the proposed RSWT feature we presented a novel machine learning based scheme to automatically detect all types of ECG characteristic points at a time. Furthermore, it showed that our algorithm achieved better performance than other reported machine learning based methods.","Title: Design in Power-Domain NOMA: Eavesdropping Suppression in the Two-User Relay Network with Compensation for the Relay User.\nYear: 2018\n\nAbstract: Non-orthogonal multiple access (NOMA) is becoming important in 5G, therefore, it is widely researched. Note that the users served in NOMA are often paired to prevent excessive interference. However, if the channel condition of direct downlink from the service node to one user is serious, the node may require the other user with better channel condition to relay this user’s signals, especially when the pure relay is difficult to deploy. This relay transmission is helpful for NOMA communication, but two problems should be considered: (i) how to persuade the relay user (i.e., the user with better channel condition) to expend extra resources for relay; (ii) how to suppress eavesdropping in the relay transmission, especially for the signals of indirect communication user (i.e., the user with worse channel condition). To solve these problems, we propose a novel signal-level scheme. In this scheme, on one hand, the node increases the spectral efficiency of relay user, and does the wireless power transfer to make the relay user supplement his/her energy by energy harvesting. On the other hand, a signal transformation method is designed to deal with each signal of indirect communication user. This transformation hides privacy information of indirect communication user, but does not disrupt the relay transmission. Utilizing the proposed scheme, the above problems are effectively solved by the compensation for the relay user and the signal protection for the indirect communication user.","Title: Structure-Aware Staging For Breast Cancer Metastases\nYear: 2018\n\nAbstract: Determining the stage of breast cancer metastases is an important component of cancer surveillance and control. It is laborious for pathologist to manually examine large amount of biological tissue and this process is error-prone. Deep learning methods can be used to automatically detect cancer metastases and identify cancer subtypes. However, current deep learning-based methods mainly focus on local patches but ignore the overall structure of lymph tissue, due to the memory limitation and computational cost of processing the gigapixel whole slide histopathological image (WSI) at a time. In this paper, we propose a structure-aware deep learning framework for staging of breast cancer metastases, in which we introduce lymph structure information to guide training patch selection and prediction features design. Our approach achieves 85.1% accuracy on slide-level and 0.80 kappa score on patient level. In addition, we see 6.1% and 5% performance gain on slide level and patient level classification respectively after introducing global structure information.","Title: Deformable MRI-Ultrasound Registration Using 3D Convolutional Neural Network.\nYear: 2018\n\nAbstract: Precise tracking of intra-operative tissue shift is important for accurate resection of brain tumor. Alignment of pre-interventional magnetic resonance imaging (MRI) to intra-operative ultrasound (iUS) is required to access tissue shift and enable guided surgery. However, accurate and robust image registration needed to relate pre-interventional MRI to iUS images is difficult due to the very different nature of image intensity between modalities. Here we present a framework that can perform non-rigid MRI-ultrasound registration using 3D convolutional neural network (CNN). The framework is composed of three components: feature extractor, deformation field generator and spatial sampler. Our automatic registration framework adopts unsupervised learning approach, allows accurate end-to-end deformable MRI-ultrasound registration. Our proposed method avoids the downfall of intensity-based methods by considering both image intensity and gradient. It achieves competitive registration accuracy on RESECT dataset. In addition, our method takes only about one second to register each image pair, enabling applications such as real time registration.","Title: Pancreatic Cancer Survival Prediction Using CT Scans and Clinical Variables.\nYear: 2018\n\nAbstract: Pancreatic cancer resulted in 411,600 deaths globally in 2015. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and it is highly lethal. Survival for patients with PDAC is dismal due to its aggressive nature, thus the development of novel and reliable prognostic model for early detection and therapy is much desired. Here we proposed a prognostic framework for prediction of overall survival of PDAC patients based on predictors derived from pancreas CT scans and patient clinical variables. Our framework includes three parts: feature extraction, feature selection and survival prediction. First, 2436 radiomics features were extracted from CT scans and were combined with the clinical variables, and a Cox model was fitted to each covariate individually to select the most predictive features. The optimal cut-off was determined by cross-validation. Finally, gradient boosting with component-wise Cox's proportional hazards model was utilized to predict the overall survival of patients. Our framework achieves excellent performance on MICCAI 2018 Pancreatic Cancer Survival Prediction Challenge dataset, achieving mean concordance index of 0.7016 using five-fold cross-validation.","Title: Unequal Secrecy Protection for Untrusted Two-Way Relaying Systems: Constellation Overlapping and Noise Aggregation.\nYear: 2018\n\nAbstract: This paper studies the secure information exchange of two-way relaying systems, where two terminal users communicate bi-directionally with the assistance of an untrusted relay. Each user is assumed to have two messages with distinct priorities: high priority and low priority. The high-priority messages (HPM) are first transmitted, for which we propose a constellation overlapping scheme such that t...","Title: A security scheme of digital rights management based on agent encryption and key distribution in cloud computing.\nYear: 2018\n\nAbstract: Cloud computing is a convenient and flexible mode of data transmission and sharing. Data security is the biggest challenge today owing to the wide application of cloud computing in various fields. This study proposed a security scheme of digital rights management based on digital license and agent encryption in cloud computing. First, a secure and effective framework of digital rights management was presented, allowing the agent encryption provider (such as centralised data server) to encrypt the data content and the common users to use the data resource based on digital license generated by a license server. The novel scheme could accomplish the privacy protection by permitting anonymous users to request different services from the key server and service provider. The performance analysis showed that the proposed scheme could assure the security and efficiency of data resource, thereby establishing its significance and application value for promoting a widespread application of cloud computing.","Title: Exploring Correlations in Multiple Facial Attributes through Graph Attention Network.\nYear: 2018\n\nAbstract: Estimating multiple attributes from a single facial image gives comprehensive descriptions on the high level semantics of the face. It is naturally regarded as a multi-task supervised learning problem with a single deep CNN, in which lower layers are shared, and higher ones are task-dependent with the multi-branch structure. Within the traditional deep multi-task learning (DMTL) framework, this paper intends to fully exploit the correlations among different attributes by constructing a graph. The node in graph represents the feature vector from a particular branch for a given attribute, and the edge can be defined by either the prior knowledge or the similarity between two nodes in the embedding with a fully data-driven manner. We analyze that the attention mechanism actually takes effect in the latter case, and utilize the Graph Attention Layer (GAL) for exploring on the most relevant attribute feature and refining the task-dependant feature by considering other attributes. Experiments show that by mining the correlations among attributes, our method can improve the recognition accuracy on CelebA and LFWA dataset. And it also achieves competitive performance.","Title: Discriminating ADHD From Healthy Controls Using a Novel Feature Selection Method Based on Relative Importance and Ensemble Learning.\nYear: 2018\n\nAbstract: Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder that often persists into adulthood, resulting in adverse effects on work performance and social function. The current diagnosis of ADHD primarily depends on the judgment of clinical symptoms, which highlights the need for objective imaging biomarkers. In this study, we aim to classify ADHD (both children and adults [34/112]) from age-matched healthy controls (HCs [28/77]) with functional connectivity (FCs) pattern derived from resting-state functional magnetic resonance imaging (rs-fMRI) data. However, the neuroimaging classification of brain disorders often meets a situation of high dimensional features were presented with limited sample size. Thus an efficient method that is able to reduce original feature dimension into a much more refined subspace is highly desired. Here we proposed a novel Feature Selection method based on Relative Importance and Ensemble Learning (FS_RIEL). Compared with traditional feature selection methods, FS_RIEL algorithm improved the ADHD classification by about 15% in both child and adult ADHD classification, achieving 80-86% accuracy. Moreover, we found the most frequently selected FCs were mainly involved in frontoparietal network, default network, salience network, basal ganglia network and cerebellum network in both child and adult ADHD cohorts, which indicates that ADHD is characterized by a widely-impaired brain connectivity profile that may serve as potential biomarkers for its early diagnosis.","Title: Saliency Detection for $\\mathbf{L}_{1/2}$ Regularization-Based SAR Image Feature Enhancement Via Bayesian Inference.\nYear: 2018\n\nAbstract: The sparse images reconstructed by conventional $mathrm{L}_{q} (0 regularization-based SAR imaging method cannot preserve the image background distribution, thus bring new challenges in SAR target detection. In this paper, we proposed a new saliency detection method for $mathrm{L}_{1/2}$ regularization-based SAR image feature enhancement. Compared with traditional saliency detection methods, our method can obtain more smooth structures and higher intensity of the bright objects, thus can obtain better target detection results. The experimental results on the miniSAR real dataset show the effective of the proposed method.","Title: A novel forwarding and routing mechanism design in SDN-based NDN architecture.\nYear: 2018\n\nAbstract: Combining named data networking (NDN) and software-defined networking (SDN) has been considered as an important trend and attracted a lot of attention in recent years. Although much work has been carried out on the integration of NDN and SDN, the forwarding mechanism to solve the inherent problems caused by the flooding scheme and discard of interest packets in traditional NDN is not well considered. To fill this gap, by taking advantage of SDN, we design a novel forwarding mechanism in NDN architecture with distributed controllers, where routing decisions are made globally. Then we show how the forwarding mechanism is operated for interest and data packets. In addition, we propose a novel routing algorithm considering quality of service (QoS) applied in the proposed forwarding mechanism and carried out in controllers. We take both resource consumption and network load balancing into consideration and introduce a genetic algorithm (GA) to solve the QoS constrained routing problem using global network information. Simulation results are presented to demonstrate the performance of the proposed routing scheme.","Title: Integrating Deep Semantic Segmentation Into 3-D Point Cloud Registration.\nYear: 2018\n\nAbstract: Point cloud registration is the task of aligning 3D scans of the same environment captured from different poses. When semantic information is available for the points, it can be used as a prior in the search for correspondences to improve registration. Semantic-assisted Normal Distributions Transform (SE-NDT) is a new registration algorithm that reduces the complexity of the problem by using the s...","Title: Amalgamating Knowledge towards Comprehensive Classification\nYear: 2018\n\nAbstract: With the rapid development of deep learning, there have been an unprecedentedly large number of trained deep network models available online. Reusing such trained models can significantly reduce the cost of training the new models from scratch, if not infeasible at all as the annotations used for the training original networks are often unavailable to public. We propose in this paper to study a new model-reusing task, which we term as knowledge amalgamation. Given multiple trained teacher networks, each of which specializes in a different classification problem, the goal of knowledge amalgamation is to learn a lightweight student model capable of handling the comprehensive classification. We assume no other annotations except the outputs from the teacher models are available, and thus focus on extracting and amalgamating knowledge from the multiple teachers. To this end, we propose a pilot two-step strategy to tackle the knowledge amalgamation task, by learning first the compact feature representations from teachers and then the network parameters in a layer-wise manner so as to build the student model. We apply this approach to four public datasets and obtain very encouraging results: even without any human annotation, the obtained student model is competent to handle the comprehensive classification task and in most cases outperforms the teachers in individual sub-tasks.","Title: A Review of Physical Layer Security Techniques for Internet of Things: Challenges and Solutions.\nYear: 2018\n\nAbstract: With the uninterrupted revolution of communications technologies and the great-leap-forward development of emerging applications, the ubiquitous deployment of Internet of Things (IoT) is imperative to accommodate constantly growing user demands and market scales. Communication security is critically important for the operations of IoT. Among the communication security provisioning techniques, physical layer security (PLS), which can provide unbreakable, provable, and quantifiable secrecy from an information-theoretical point of view, has drawn considerable attention from both the academia and the industries. However, the unique features of IoT, such as low-cost, wide-range coverage, massive connection, and diversified services, impose great challenges for the PLS protocol design in IoT. In this article, we present a comprehensive review of the PLS techniques toward IoT applications. The basic principle of PLS is first briefly introduced, followed by the survey of the existing PLS techniques. Afterwards, the characteristics of IoT are identified, based on which the challenges faced by PLS protocol design are summarized. Then, three newly-proposed PLS solutions are highlighted, which match the features of IoT well and are expected to be applied in the near future. Finally, we conclude the paper and point out some further research directions.","Title: Encryption Over the Air: Securing Two-Way Untrusted Relaying Systems Through Constellation Overlapping.\nYear: 2018\n\nAbstract: This paper proposes a novel technique called constellation overlapping to secure two-way untrusted relaying systems. We first consider the symmetric case where two terminal users adopt the same modulation type. For this case, a truncated-channel-inversion-based approach is developed to make the signals from different users experience the same equivalent channel, thereby realizing full constellatio...","Title: Multi-Model Feedforward Dynamic Matrix Control Of Polymer Membrane Fuel Cell With Dead-Ended Anode And Cyclic Purge Process\nYear: 2018\n\nAbstract: This paper proposes a control strategy for a Polymer Electrolyte Membrane Fuel Cell (PEMFC) with a dead-ended anode (DEA) and cyclic purge process using Multi-model Feedforward Dynamic Matrix Control (MFDMC) with a switch law. MFDMC is a model-based predictive control method, which has superiority in addressing control problems with constraints and nonlinearity. The control objective is to maintain a low differential pressure across the membrane against the disturbance of the purge process and load change. A mathematical model is built and its dynamics is recognized at varied operating conditions to demonstrate the transient behavior of a PEMFC stack Simulation results show the ability of the MFDMC to compensate the influence of periodic purging and load change without constraint violation of the actuator.","Title: Method of Synthesizing Orthogonal Beam-Forming Networks Using QR Decomposition.\nYear: 2019\n\nAbstract: A synthesis method for orthogonal beam-forming networks (BFNs) with arbitrary N inputs and N outputs is presented. Compared to those formerly developed, the new method allows the design of a BFN in order to not only generate arbitrary N orthogonal beams and N inputs but also to make the 180° hybrids less. This skill is obtained by means of a new approach to decompose the matrices $Q_{1}$ and $Q...","Title: Multisensor Online Transfer Learning For 3d Lidar-Based Human Detection With A Mobile Robot\nYear: 2018\n\nAbstract: Human detection and tracking is an essential task for service robots, where the combined use of multiple sensors has potential advantages that are yet to be fully exploited. In this paper, we introduce a framework allowing a robot to learn a new 3D LiDAR-based human classifier from other sensors over time, taking advantage of a multisensor tracking system. The main innovation is the use of different detectors for existing sensors (i.e. RGB-D camera, 2D LiDAR) to train, online, a new 3D LiDAR-based human classifier based on a new \"trajectory probability\". Our framework uses this probability to check whether new detection belongs to a human trajectory, estimated by different sensors and/or detectors, and to learn a human classifier in a semi-supervised fashion. The framework has been implemented and tested on a real-world dataset collected by a mobile robot. We present experiments illustrating that our system is able to effectively learn from different sensors and from the environment, and that the performance of the 3D LiDAR-based human classification improves with the number of sensors/detectors used.","Title: A Data Reuse Method for Fast Search Motion Estimation.\nYear: 2018\n\nAbstract: In motion estimation, the search regions of two adjacent current blocks have overlapping data. In view of this, the paper proposes a data reuse method for fast search motion estimation. The method reuses the overlapping data between the search areas of two adjacent blocks. The overlapping data are further divided into two parts, a definite data reuse area and a possible data reuse area. With this method, the memory access time of the algorithm is reduced, and the performance of the algorithm is further improved. And the proposed reuse method can effectively reduce the loading of redundant data. A typical fast search algorithm, diamond search, is used as a case study to verify the effectiveness of the method. The method is implemented on GPU platform. The experimental results show that the data reuse method can reduce the running time by 40%–60% compared with the algorithm of no use data reuse.","Title: Information To Intelligence(Itoi): An Adaptive And Intelligent Prototype Of Knowledge Construction For College Student\nYear: 2018\n\nAbstract: An adaptive and intelligent prototype of knowledge construction for college students, information to Intelligence(itoI), is proposed in this paper. During the process of knowledge construction, the system records all kinds of online study performance of each student, and then interdisciplinary coursework is automatically assigned to the right students. Both the student and the system improve their knowledge level and intelligence level adaptively. Through the random survey on college student of Shandong Normal University, the results show that it is useful for guiding the process of online learning.","Title: Instantaneous Power Control Of A High Speed Permanent Magnet Synchronous Generator Based On A Sliding Mode Observer And A Phase Locked Loop\nYear: 2017\n\nAbstract: This paper proposes an instantaneous power control method for high speed permanent magnet synchronous generators (PMSG), to realize the decoupled control of active power and reactive power, through vector control based on a sliding mode observer (SMO), and a phase locked loop (PLL). Consequently, the high speed PMSG has a high internal power factor, to ensure efficient operation. Vector control and accurate estimation of the instantaneous power require an accurate estimate of the rotor position. The SMO is able to estimate the back electromotive force (EMF). The rotor position and speed can be obtained using a combination of the PLL technique and the phase compensation method. This method has the advantages of robust operation, and being resistant to noise when estimating the position of the rotor. Using instantaneous power theory, the relationship between the output active power, reactive power, and stator current of the PMSG is deduced, and the power constraint condition is analysed for operation at the unit internal power factor. Finally, the accuracy of the rotor position detection, the instantaneous power detection, and the control methods are verified using simulations and experiments.","Title: Fountain-Coding-Based Secure Communications Exploiting Outage Prediction and Limited Feedback.\nYear: 2019\n\nAbstract: This paper develops a fountain-coding-based scheme to secure communications over fading wiretap channels, in which the transmission between the legitimate nodes is overheard by a malicious eavesdropper. The transmitter first splits its message into K source packets and generates a potentially infinite number of fountain-coded packets, each of which is the XOR of distinct source packets chosen acco...","Title: Segmentation Of Pathological Features Of Rat Bile Duct Carcinoma From Hyperspectral Images\nYear: 2018\n\nAbstract: Liver disease has always been one of the key concerns of the medical community. In recent years, liver diagnostic techniques such as serology have been continuously developed, but the pathological diagnosis of the liver, especially the advancement of liver biopsy technology, is still the most reliable basis for the diagnosis and treatment of liver diseases. In this paper, pathological sections of rat bile duct carcinoma were used as experimental samples to identify and analyze liver tumor by microscopic hyperspectral imaging (MHSI) technique. The proposed method combines the Otsu (OTSU) algorithm with the support vector machine (SVM) algorithm to segment the liver tumor, and comparing with SVM segmentation results. Experimental results show that the OTSU-SVM method has an accuracy of 94.59% which provides a potential reference value for the pathological diagnosis of liver tumors.","Title: Detection Of Mycobacterium Tuberculosis In Ziehl-Neelsen Sputum Smear Images\nYear: 2018\n\nAbstract: Tuberculosis is one of the top 10 causes of death worldwide. In order to reduce the workload of doctors and the probability of human error, this paper presents an automatic detection algorithm for Mycobacterium tuberculosis in Ziehl-Neelsen Sputum Smear Images. The algorithm uses color feature and three morphological characters, which are aspect ratio, circularity and area. Background Equalization algorithm is proposed to utilize color feature sufficiently. This algorithm takes advantage of the watershed algorithm and the channel \"a\" in Lab color space. Experimental results accuracy of the proposed algorithm.","Title: Autonomous Clothes Manipulation Using a Hierarchical Vision Architecture.\nYear: 2018\n\nAbstract: This paper presents a novel robot vision architecture for perceiving generic 3-D clothes configurations. Our architecture is hierarchically structured, starting from low-level curvature features to mid-level geometric shapes and topology descriptions, and finally, high-level semantic surface descriptions. We demonstrate our robot vision architecture in a customized dual-arm industrial robot with our in-house developed stereo vision system, carrying out autonomous grasping and dual-arm flattening. The experimental results show the effectiveness of the proposed dual-arm flattening using the stereo vision system compared with the single-arm flattening using the widely cited Kinect-like sensor as the baseline. In addition, the proposed grasping approach achieves satisfactory performance when grasping various kind of garments, verifying the capability of the proposed visual perception architecture to be adapted to more than one clothing manipulation tasks.","Title: Disentangling Latent Space For Vae By Label Relevant/Irrelevant Dimensions\nYear: 2018\n\nAbstract: VAE requires the standard Gaussian distribution as a prior in the latent space. Since all codes tend to follow the same prior, it often suffers the so-called \"posterior collapse\". To avoid this, this paper introduces the class specific distribution for the latent code. But different from cVAE, we present a method for disentangling the latent space into the label relevant and irrelevant dimensions, z(s) and z(u), for a single input. We apply two separated encoders to map the input into z(s) and z(u) respectively, and then give the concatenated code to the decoder to reconstruct the input. The label irrelevant code zu represent the common characteristics of all inputs, hence they are constrained by the standard Gaussian, and their encoder is trained in amortized variational inference way, like VAE. While z(s) is assumed to follow the Gaussian mixture distribution in which each component corresponds to a particular class. The parameters for the Gaussian components in z(s) encoder are optimized by the label supervision in a global stochastic way. In theory, we show that our method is actually equivalent to adding a KL divergence term on the joint distribution of z(s) and the class label c, and it can directly increase the mutual information between z(s) and the label c. Our model can also be extended to GAN by adding a discriminator in the pixel domain so that it produces high quality and diverse images.","Title: A Multi-Dimensional Hyperspectral Image Mosaic Method and its Acquisition System.\nYear: 2018\n\nAbstract: With the combination of both spectral and spatial information, hyperspectral images can offer much detailed information for researchers. In this paper, a multi-dimensional hyperspectral image mosaic method has been proposed to stitch hyperspectral images. This method combines texture information of the single gray image, spatial information of the hyperspectral image and the position information gathered during the acquisition process. We apply this method to the medical hyperspectral image stitch and the experimental results prove the accuracy of this method compared to other single-dimensional methods.","Title: Development of 3D Exhibition System for IoT-Oriented Simulation Platform.\nYear: 2018\n\nAbstract: This paper develops an exhibition system based on the system-level simulation platform for massive wireless access of IoT. The system appends a complete data output mechanism based on the original simulation platform, which provides a convenient environment for development and debugging, observation of system process and performance evaluation for the NB-IoT simulation platform. The exhibition system includes multiple modules, such as a data processing module, a driving engine module, a drawing module and a 3D scene module. Meanwhile, the system designs multiple interaction modules to restore the simulation details. Finally, this paper completes the debugging of the system, analyzes and discusses the results.","Title: An innovative control strategy for a hybrid energy storage system (HESS)\nYear: 2017\n\nAbstract: Electric Vehicles (EVs) adopting both batteries and supercapacitors have attracted a significant amount of attention in research communities due to its unique power sharing capabilities. A Hybrid Energy Storage System (HESS) can effectively reduce power stress that would otherwise be applied to batteries alone, and whose weight and size is still a common concern when competing against conventional ICE-powered cars. In this paper, a high-level control strategy is developed to adaptively split the load between two sources for an electric vehicle adopting HESS under real-life load fluctuations. A converter - Supercapacitor Pack (SP) coupled HESS upon which such an algorithm is deployed on, is proposed to divert excess power into the SP via a smart Power Converter (PC) which is located in between in order to regulate both behaviors. Such a power split strategy (PSS) is designed in such a way to track real-time load profiles and determines one important variable - the cut-off frequency. A simplified HESS model is first developed. The power split algorithm is coded in Matlab and then applied to this HESS model. Finally, the overall system is tested comprehensively over 4 EPA driving cycles. Simulation results prove its effectiveness in coping with even the harshest driving scenarios in real life.","Title: On Secure Simple Pairing in Bluetooth Standard v5.0-Part I: Authenticated Link Key Security and Its Home Automation and Entertainment Applications.\nYear: 2019\n\nAbstract: Bluetooth is an important technical standard for short-range and low-power wireless communication. The home automation and entertainment (HAE) systems often make use of Bluetooth technology to link different Bluetooth devices and form Bluetooth networks. The security concerns of the HAE systems are raised due to massive deployment of the Bluetooth devices. The Bluetooth standard mainly depends on the secure simple pairing (SSP) solution to protect the Bluetooth devices. Hence, we investigate the SSP solution according to the Bluetooth standard v5.0. The contributions are threefold. (1) A formal security model is proposed to evaluate SSP's association models and authenticated link key. (2) We formally analyze two SSP protocols and present the security requirements for basic cryptographic modules in these SSP protocols. (3) We discuss the typical SSP applications in the HAE systems. Our results are useful to not only evaluating and designing the SSP protocols but also enhancing the security of the HAE systems in which the Bluetooth access is available.","Title: Microwave Non-Destructive Inspection and Prediction of Modulus of Rupture and Modulus of Elasticity of Engineered Cementitious Composites (ECCs) Using Dual-Frequency Correlation.\nYear: 2017\n\nAbstract: This research article presents dual-frequency correlation models for predicting the growth of elasticity and flexural strength of engineered cementitious composites (ECCs) using microwave nondestructive inspection technique. Parallel measurements of microwave properties and mechanical properties of ECC specimens were firstly undertaken in the sense of cross-disciplinary experiments. Regression models were developed via means of nonlinear regression to the measured data. The purpose of the study is: (i) to monitor the flexural strength and elasticity growth; and (ii) to predict their mature values under the influence of different initial water contents, via microwave effective conductance at early ages. It has been demonstrated that both the modulus of rupture (MOR) and modulus of elasticity (MOE) can be accurately modeled and correlated by microwave conductance using exponential functions. The moduli developed as a function of conductance whereas the regression coefficient exhibited a linear relation with water-to-binder ratio. These findings have highlighted the effectiveness of the microwave non-destructive technique in inspecting the variation of liquid phase morphology of ECCs. The dual-frequency correlation can be used for structural health monitoring, which is not only for prediction but also provides a means of verification.","Title: A Novel Parameter Determination Method for Lq Regularization Based Sparse SAR Imaging\nYear: 2017\n\nAbstract: Sparse SAR imaging based on Lq(0 u003c q u003c 1) regularization has become a hot issue in SAR imaging. However, it can be difficult to determine a suitable value of the regularization parameter. In this paper, we developed a novel adaptive regularization parameter determination method for Lq regularization based SAR imaging. On the basis that the noise type in SAR system is mostly additive Gaussian white noise, we present a method for determining the regularization parameter through evaluating the statistics of noise. The parameter is updated through validating the statistical properties of the reconstruction error residuals in a suitable Noise Confidence Region (NCR). The experiment results illustrate the validity of the proposed method.","Title: An Orthonormalized Basis Function Algorithm Based On Wavelet Analysis For Magnetic Anomaly Detection\nYear: 2017\n\nAbstract: This Magnetic Anomaly Detection (MAD) technology is widely used in various fields in recent years. The focus of most researches is how to improve the signal recognition rate and reduce the false alarm rate. This paper presents an improved Orthonormalized Basis Function (OBF) algorithm for MAD in non-Gaussian noise background. In this algorithm, the raw signal is first decomposed by the wavelet. Then several layers of the decomposed signal with target characteristics are picked out as the reconstructed signal. Finally the magnetic target is recognized by the OBF algorithm. The experimental results show that the noise of the signal can be suppressed to a certain extent and the SNR is improved. Compared with the traditional OBF algorithm, the wavelet analysis based OBF algorithm can detect the target signal accurately and reduce the waste of resources caused by the false alarms.","Title: Detection of 3-D objects with a 2-D laser scanning sensor for greenhouse spray applications.\nYear: 2018\n\nAbstract: •Accuracy of an inexpensive laser scanning sensor for detecting objects was validated.•An algorithm was designed to measure object dimensions under various conditions.•Pseudo-color images were used to map surfaces of complex-shaped objects and plants.•Implementing the laser sensor to guide greenhouse spray applications were proposed.","Title: A generic integrity verification algorithm of version files for cloud deduplication data storage\nYear: 2018\n\nAbstract: Data owners’ outsourced data on cloud data storage servers by the deduplication technique can reduce not only their own storage cost but also cloud’s. This paradigm also introduces new security issues such as the potential threat of data lost or corrupted. Data integrity verification is utilized to safeguard these data integrity. However, the cloud deduplication storage only focuses on file/chunk level to store one copy of the same data hosted by different data owners, and is not concerned with the same part of different data, e.g., a series of version files. We propose an integrity verification algorithm of different version files. The algorithm establishes the generic storage model of different version control methods to improve the universality of data verification. Then, the methods of verification tags and proofs generating are improved based on the index pointers corresponding to the storage relationship in the version groups and chained keys. Finally, the random diffusion extraction based on the random data sampling in the version group is proposed to improve the verification efficiency. The results of theoretical and experimental analysis indicate that the algorithm can achieve fast and large-scale verification for different version data.","Title: The Strain Transfer Mechanism of Fiber Bragg Grating Sensor for Extra Large Strain Monitoring.\nYear: 2019\n\nAbstract: This research focuses on a desensitization method to develop a wide-range FBG sensor for extra-large strain monitoring, which is an essential requirement in large scale infrastructures or for some special occasions. Under appropriate hypotheses, the strain transfer distribution of wide-range FBG sensor based on the shear-lag theory is conducted to improve the accuracy of extra-large strain measurements. It is also discussed how the elastic modulus of adhesive layer affects the strain transfer rate. Two prototypes in different monitoring ranges are designed and fabricated by two layers of steel pipe encapsulation. The presented theoretical model is verified by experimental results. Moreover, it is demonstrated that experimentation in regards to the calibration of the wide-range FBG sensor, improved the amplification coefficient up to 2.08 times and 3.88 times, respectively. The static errors are both calculated and analyzed in this experiment. The wide-range FBG strain sensor shows favourable linearity and stability, which is an excellent property of sensors for extra-large strain monitoring.","Title: A self-propelled robotic system with a visco-elastic joint: dynamics and motion analysis\nYear: 2020\n\nAbstract: This paper studies the dynamics and motion generation of a self-propelled robotic system with a visco-elastic joint. The system is underactuated, legless and wheelless, and has potential applications in environmental inspection and operation in restricted spaces which are inaccessible to human beings, such as pipeline inspection, medical assistance and disaster rescue. Locomotion of the system relies on the stick–slip effects, which interacts with the frictional force of the surface in contact. The nonlinear robotic model utilizes combined tangential-wise and normal-wise vibrations for underactuated locomotion, which features a generic significance for the studies on self-propelled systems. To identify the characteristics of the visco-elastic joint and shed light on the energy efficacy, parameter dependences on stiffness and damping coefficients are thoroughly analysed. Our studies demonstrate that the dynamic behaviour of the self-propelled system is mainly periodic and desirable forward motion is achieved via identification of the variation laws of the control parameters and elaborate selection of the stiffness and damping coefficients. A motion generation strategy is developed, and an analytical two-stage motion profile is proposed based on the system response and dynamic constraint analysis, followed by a parameterization procedure to optimally generate the trajectory. The proposed method provides a novel approach in generating self-propelled locomotion, and designing and computing the visco-elastic parameters for energy efficacy. Simulation results are presented to demonstrate the effectiveness and feasibility of the proposed model and motion generation approach.","Title: Spatio-temporal deep learning method for ADHD fMRI classification\nYear: 2019\n\nAbstract: •Fusing spatial and temporal features is effective in fMRI classification.•Models considering sequence achieve better results than timing invariant models.•fMRI scans longer than one minute contain enough information for ADHD diagnosis.•deep-learned features outperform hand-crafted features in fMRI analysis.","Title: Continuous perception for deformable objects understanding\nYear: 2019\n\nAbstract: We present a robot vision approach to deformable object classification, with direct application to autonomous service robots. Our approach is based on the assumption that continuous perception provides robots with greater visual competence for deformable objects interpretation and classification. Our approach classifies the category of clothing items by continuously perceiving the dynamic interactions of the garment’s material and shape as it is being picked up. For this, we extract continuously visual features of a RGB-D video sequence and we fuse features by means of the Locality Constrained Group Sparse Representation (LGSR) algorithm. To evaluate the performance of our approach, we created a fully annotated database featuring 150 garment videos in random configurations. Experiments demonstrate that by continuously observing an object deform, our approach achieves a classification score of 66.7%, outperforming state-of-the-art approaches by a ∼27.3% increase.","Title: Radar Signal Processing for Sensing in Assisted Living: The challenges associated with real-time implementation of emerging algorithms\nYear: 2019\n\nAbstract: This article covers radar signal processing for sensing in the context of assisted living (AL). This is presented through three example applications: human activity recognition (HAR) for activities of daily living (ADL), respiratory disorders, and sleep stages (SSs) classification. The common challenge of classification is discussed within a framework of measurements/preprocessing, feature extraction, and classification algorithms for supervised learning. Then, the specific challenges of the three applications from a signal processing standpoint are detailed in their specific data processing and ad hoc classification strategies. Here, the focus is on recent trends in the field of activity recognition (multidomain, multimodal, and fusion), health-care applications based on vital signs (superresolution techniques), and comments related to outstanding challenges. Finally, this article explores challenges associated with the real-time implementation of signal processing/classification algorithms.","Title: Dna: Dynamic Social Network Alignment\nYear: 2019\n\nAbstract: Social network alignment, aligning different social networks on their common users, is receiving dramatic attention from both academic and industry. All existing studies consider the social network to be static and neglect its inherent dynamics. In fact, the dynamics of social networks contain the discriminative pattern of an individual, which can be leveraged to facilitate social network alignment. Hence, we for the first time propose to study the problem of aligning dynamic social networks. Towards this end, we propose a novel Dynamic social Network Alignment (DNA) framework, a unified optimization approach over deep neural architectures, to unfold the fruitful dynamics to perform alignment. However, it faces tremendous challenges in both modeling and optimization: (1) To model the intranetwork dynamics, we explore the local dynamics of the latent pattern in friending evolvement and the global consistency of the representation similarity with neighbors. We design a novel deep neural architecture to obtain the dual embedding capturing local dynamics and global consistency for each user. (2) To model the inter-network alignment, we exploit the underlying identity of an individual from the dual embedding in each dynamic social network. We design a unified optimization approach interplaying proposed deep neural architectures to construct a common subspace of identity embeddings. (3) To address this optimization problem, we design an effective alternating algorithm with solid theoretical guarantees. We conduct extensive experiments on realworld datasets and show that the proposed DNA framework substantially outperforms the state-of-the-art methods.","Title: Deepblue: Bi-Layered Lstm For Tweet Popularity Estimation\nYear: 2019\n\nAbstract: In social networks, one of the most significant challenges is how to estimate the tweet popularity. Prior studies about this problem focus on leveraging different aspects of just a single tweet, while ignoring the impact of historical tweets. In this paper, we propose to leverage such historical information and rethink the problem of tweet popularity estimation. From historical information, there are two important factors that can be extracted: (1) user reputation feature, which can represent coarse-grained level of tweet popularity; (2) tweet related features, which can represent fine-grained level of tweet popularity. To incorporate two factors from historical information, we design a novel deep neural architecture, a Bi-layered LSTM for tweet popUlarity Estimation, called DeepBlue. Specifically, we first propose a user-reputation aware mechanism to combine coarse-grained and fine-grained level estimation into a unified LSTM model. We then propose a time aware mechanism to address the time interval irregularity issue in standard LSTM. Finally, we apply the Poisson regression model to obtain the overall loss for tweet popularity estimation. Extensive experiments demonstrate the superiority of our proposed approach to other state-of-the-arts in terms of MAE and SRC.","Title: Value-Aware Resampling And Loss For Imbalanced Classification\nYear: 2018\n\nAbstract: Existing(1) machine learning methods usually treat training samples equally, and their performance degrades significantly when facing imbalanced training data. This paper introduces Value-Aware Resampling and Loss (VARL) to tackle the imbalanced classification problem, where high-value samples play a more important role than those of low-value samples in the model training process. Specifically, the training value of each training sample is assessed according to its predicted probability of ground truth label, and then training samples are resampled to produce a balanced training set, at last the model training is further boosted by using an instance-level value-aware loss function. To conduct fair comparisons among different methods, we compile 13 datasets for imbalanced classification. Experiments demonstrate that our proposed method can effectively measure the training value of training samples, and achieve superior performance in imbalanced classification compared with several existing methods.","Title: Hyperbolic Variational Graph Neural Network For Modeling Dynamic Graphs\nYear: 2021\n\nAbstract: Learning representations for graphs plays a critical role in a wide spectrum of downstream applications. In this paper, we summarize the limitations of the prior works in three folds: representation space, modeling dynamics and modeling uncertainty. To bridge this gap, we propose to learn dynamic graph representation in hyperbolic space, for the first time, which aims to infer stochastic node representations. Working with hyperbolic space, we present a novel Hyperbolic Variational Graph Neural Network, referred to as HVGNN. In particular, to model the dynamics, we introduce a Temporal GNN (TGNN) based on a theoretically grounded time encoding approach. To model the uncertainty, we devise a hyperbolic graph variational autoencoder built upon the proposed TGNN to generate stochastic node representations of hyperbolic normal distributions. Furthermore, we introduce a reparameterisable sampling algorithm for the hyperbolic normal distribution to enable the gradient-based learning of HVGNN. Extensive experiments show that HVGNN outperforms state-of-the-art baselines on real-world datasets.","Title: Bandwidth-Efficient Precoding in Cell-Free Massive MIMO Networks with Rician Fading Channels\nYear: 2021\n\nAbstract: Global precoding is an effective way to suppress interference in cell-free massive MIMO systems. However, it requires all access points (APs) to upload their local instantaneous channel state information (CSI) to a central processor via capacity-constrained fronthaul links, consuming significant bandwidth resources. Such overhead may become unaffordable in an ultra-dense network (UDN) in future 5G systems, due to the large number of APs and the frequent CSI uploads required to combat the fast-changing state of the high-frequency channels. In order to address this issue, we propose a novel bandwidth-efficient global zero-forcing precoding strategy for downlink transmission in cell-free massive MIMO systems. By exploiting the physical structure of Rician fading channels, we propose a novel model-based CSI compression mechanism, which decomposes a channel matrix into a line-of-sight (LoS) and a non-line-of-sight (NLoS) components, and then compresses them using a model-based method and a singular-value-decomposition (SVD)-based method, respectively. We also present two optimization-based algorithms to obtain the phase information of the LoS component of the channel, which is then used by the proposed channel matrix decomposition. The simulation results demonstrate the efficiency of the proposed precoding strategy on reducing the upload overhead and improving the bandwidth efficiency.","Title: A Novel Wide-Baseline Stereo Matching Algorithm Combining Mser And Daisy\nYear: 2018\n\nAbstract: Image(1) matching is a fundamental problem in Computer Vision. In the context of feature-based matching, SIFT (Scale-Invariant Feature Transform) and its variants have long excelled in a wide array of applications. However, for wide-baseline images, it is more challenging due to large perspective distortions. In this paper, we introduce a novel affine invariant feature algorithm combining MSER (Maximum Stable Extreme Region) and DAISY descriptor for wide-baseline scenarios. Firstly, MSER algorithm is used to detect maximum stable extreme regions. Then the MSER region is fit to an elliptical shape. The ellipse area is normalized of direction and shape using the dominant orientation and the length of long and short axes of ellipse, respectively. And square feature region is resampled to a specified radius size. Finally, the DAISY descriptor is used to establish descriptor. The algorithm is validated by using benchmark images and real-world images. We demonstrate that our method has better reliability and is superior to SIFT and MSER+SIFT algorithm in the case of wide-baseline.","Title: Tree-like Decision Distillation\nYear: 2021\n\nAbstract: Knowledge distillation pursues a diminutive yet well-behaved student network by harnessing the knowledge learned by a cumbersome teacher model. Prior methods achieve this by making the student imitate shallow behaviors, such as soft targets, features, or attention, of the teacher. In this paper, we argue that what really matters for distillation is the intrinsic problem-solving process captured by the teacher. By dissecting the decision process in a layer-wise manner, we found that the decision-making procedure in the teacher model is conducted in a coarse-to-fine manner, where coarse-grained discrimination (e.g., animal vs vehicle) is attained in early layers, and fine-grained discrimination (e.g., dog vs cat, car vs truck) in latter layers. Motivated by this observation, we propose a new distillation method, dubbed as Tree-like Decision Distillation (TDD), to endow the student with the same problem-solving mechanism as that of the teacher. Extensive experiments demonstrated that TDD yields competitive performance compared to state of the arts. More importantly, it enjoys better interpretability due to its interpretable decision distillation instead of dark knowledge distillation.","Title: Examining rice distribution and cropping intensity in a mixed single- and double-cropping region in South China using all available Sentinel 1/2 images\nYear: 2021\n\nAbstract: •Optimize sensors and features for identifying early, middle, and late rice.•Generate 10-m cropping intensity map by integrating Sentinel-1 and -2 images.•Single rice cropping dominates the cropping system in the study area in 2017.","Title: Can contrastive learning avoid shortcut solutions?\nYear: 2021\n\nAbstract: The generalization of representations learned via contrastive learning depends crucially on what features of the data are extracted. However, we observe that the contrastive loss does not always sufficiently guide which features are extracted, a behavior that can negatively impact the performance on downstream tasks via “shortcuts\", i.e., by inadvertently suppressing important predictive features. We find that feature extraction is influenced by the difficulty of the so-called instance discrimination task (i.e., the task of discriminating pairs of similar points from pairs of dissimilar ones). Although harder pairs improve the representation of some features, the improvement comes at the cost of suppressing previously well represented features. In response, we propose implicit feature modification (IFM), a method for altering positive and negative samples in order to guide contrastive models towards capturing a wider variety of predictive features. Empirically, we observe that IFM reduces feature suppression, and as a result improves performance on vision and medical imaging tasks.","Title: Intention-aware Heterogeneous Graph Attention Networks for Fraud Transactions Detection\nYear: 2021\n\nAbstract: ABSTRACTFraud transactions have been the major threats to the healthy development of e-commerce platforms, which not only damage the user experience but also disrupt the orderly operation of the market. User behavioral data is widely used to detect fraud transactions, and recent works show that accurate modeling of user intentions in behavioral sequences can propel further improvements on the performances. However, most existing methods treat each transaction as an independent data instance without considering the transaction-level interactions accessed by transaction attributes, e.g., information on remark, logistics, payment, device and etc., which may fail to achieve satisfactory results in more complex scenarios. In this paper, a novel heterogeneous transaction-intention network is devised to leverage the cross-interaction information over transactions and intentions, which consists of two types of nodes, namely transaction and intention nodes, and two types of edges, i.e., transaction-intention and transaction-transaction edges. Then we propose a graph neural method coined IHGAT(Intention-aware Heterogeneous Graph ATtention networks) that not only perceives sequence-like intentions, but also encodes the relationship among transactions. Extensive experiments on a real-world dataset of Alibaba platform show that our proposed algorithm outperforms state-of-the-art methods in both offline and online modes.","Title: PROGRESSIVE MULTI-STAGE FEATURE MIX FOR PERSON RE-IDENTIFICATION\nYear: 2021\n\nAbstract: Image features from a small local region often give strong evidence in person re-identification task. However, CNN suffers from paying too much attention on the most salient local areas, thus ignoring other discriminative clues, e.g., hair, shoes or logos on clothes. In this work, we propose a Progressive Multi-stage feature Mix network (PMM), which enables the model to find out the more precise and diverse features in a progressive manner. Specifically, (i) to enforce the model to look for different clues in the image, we adopt a multi-stage classifier and expect that the model is able to focus on a complementary region in each stage. (ii) we propose an Attentive feature Hard-Mix (A-Hard-Mix) to replace the salient feature blocks by the negative example in the current batch, whose label is different from the current sample. (iii) extensive experiments have been carried out on reID datasets such as the Market-1501, DukeMTMC-reID and CUHK03, showing that the proposed method can boost the re-identification performance significantly. Source code(1) has been released.","Title: Deep 3D caricature face generation with identity and structure consistency\nYear: 2021\n\nAbstract: This paper proposed a novel approach to generate face caricatures automatically from a single portrait image. We decompose the process of 3D face caricatures generation into two independent subtasks: appearance transfer of texture and the geometry transfer of mesh. For the appearance transfer, we design a GAN-based network named CariFaceGAN to learn the style mapping from portrait to caricature, in which facial features are leveraged to preserve identity consistency. For geometry transfer, we first learn the transformation of the landmarks between portraits and caricatures in an embedded space obtained with Locally Linear Embedding method, and then Kriging interpolation is used to manipulate the portrait mesh constructed from a single image. The experimental results show that our proposed CariFaceGAN outperforms the state-of-the-art methods in terms of maintaining identity consistency and providing satisfactory visual effects.","Title: Self-Attention-Based Real-Time Signal Detector for Communication Systems With Unknown Channel Models\nYear: 2021\n\nAbstract: In this letter, a deep-learning-assisted signal detector is developed for communication systems with unknown channel models. By embedding domain knowledge into a self-attention model, a novel detection unit is devised that enables both reliable estimation and fast training. Furthermore, a sliding-window structure is in combined use with the detection unit to realize real-time signal recovery. We evaluate the performance of the proposed detector using a chemical communication experimental platform, and show the superiority of our design in terms of detection accuracy as well as implementation complexity.","Title: Reducing The Influence Of Environmental Factors On Performance Of A Diffusion-Based Personal Exposure Kit\nYear: 2021\n\nAbstract: Sensor technology has enabled the development of portable low-cost monitoring kits that might supplement many applications in conventional monitoring stations. Despite the sensitivity of electrochemical gas sensors to environmental change, they are increasingly important in monitoring polluted microenvironments. The performance of a compact diffusion-based Personal Exposure Kit (PEK) was assessed for real-time gaseous pollutant measurement (CO, O-3, and NO2) under typical environmental conditions encountered in the subtropical city of Hong Kong. A dynamic baseline tracking method and a range of calibration protocols to address system performance were explored under practical scenarios to assess the performance of the PEK in reducing the impact of rapid changes in the ambient environment in personal exposure assessment applications. The results show that the accuracy and stability of the ppb level gas measurement is enhanced even in heterogeneous environments, thus avoiding the need for data post-processing with mathematical algorithms, such as multi-linear regression. This establishes the potential for use in personal exposure monitoring, which has been difficult in the past, and for reporting more accurate and reliable data in real-time to support personal exposure assessment and portable air quality monitoring applications.","Title: Inductive and irregular dynamic network representation based on ordinary differential equations\nYear: 2021\n\nAbstract: Dynamic network representation has aroused increasing attention from researchers since it reflects the characteristics of real-world networks and has been widely used in various applications. Enormous efforts have been made to this problem. Existing studies often use fixed-time steps. However, in fact, the dynamics in real-world networks are usually irregular over time. To address this problem, in this paper, we employ ordinary differential equations and propose a novel graph representation approach for dynamic networks, namely Graph-ODE. The core idea lies in that it leverages ordinary differential equations to model the continuous latent dynamics of the network and therefore can naturally capture the evolution pattern. Specifically, to deal with the irregularity of node interactions, we first propose a differential form of GRU aggregator to aggregate the chronological neighbors. In addition, we employ neighbor sampling strategies for efficiency. Besides, our inductive algorithm owns the ability to deal with new emerging nodes. Experimental results on various real-world data sets demonstrate that our method significantly outperforms several state-of-the-art algorithms on downstream tasks.","Title: A Quantifiable Stratification Strategy for Tidy-up in Service Robotics\nYear: 2021\n\nAbstract: This paper addresses the problem of tidying up a living room in a messy condition with a service robot (i.e. domestic mobile manipulator). One of the key issues in completing such a task is how to continuously select the object to grasp and take it to the delivery area, especially when the robot works in constrained and partially observable environments. In this paper, we propose a quantifiable st...","Title: Disassembling object representations without labels\nYear: 2021\n\nAbstract: •We introduce the disassembling task and an unsupervised approach towards solving it.•UDOR is devised to comply with the modularity of the learned latent representation.•We also introduce two metrics for evaluating the disassembling performance.","Title: Bridging the Gap between Label- and Reference-based Synthesis in Multi-attribute Image-to-Image Translation.\nYear: 2021\n\nAbstract: The image-to-image translation (I2IT) model takes a target label or a reference image as the input, and changes a source into the specified target domain. The two types of synthesis, either label- or reference-based, have substantial differences. Particularly, the label-based synthesis reflects the common characteristics of the target domain, and the reference-based shows the specific style similar to the reference. This paper intends to bridge the gap between them in the task of multi-attribute I2IT. We design the label- and reference-based encoding modules (LEM and REM) to compare the domain differences. They first transfer the source image and target label (or reference) into a common embedding space, by providing the opposite directions through the attribute difference vector. Then the two embeddings are simply fused together to form the latent code S_rand (or S_ref), reflecting the domain style differences, which is injected into each layer of the generator by SPADE. To link LEM and REM, so that two types of results benefit each other, we encourage the two latent codes to be close, and set up the cycle consistency between the forward and backward translations on them. Moreover, the interpolation between the S_rand and S_ref is also used to synthesize an extra image. Experiments show that label- and reference-based synthesis are indeed mutually promoted, so that we can have the diverse results from LEM, and high quality results with the similar style of the reference.","Title: Introspective Visuomotor Control: Exploiting Uncertainty in Deep Visuomotor Control for Failure Recovery\nYear: 2021\n\nAbstract: End-to-end visuomotor control is emerging as a compelling solution for robot manipulation tasks. However, imitation learning-based visuomotor control approaches tend to suffer from a common limitation, lacking the ability to recover from an out-of-distribution state caused by compounding errors. In this paper, instead of using tactile feedback or explicitly detecting the failure through vision, we...","Title: Exploring Pathologist Knowledge for Automatic Assessment of Breast Cancer Metastases in Whole-slide Image\nYear: 2021\n\nAbstract: ABSTRACTAutomatic assessment of breast cancer metastases plays an important role to help pathologist reduce the time-consuming work in histopathological whole-slide image diagnosis. From the utilization of knowledge point of view, the low-magnification level and high-magnification level are carefully checked by the pathologists for tumor pattern and cell tumor characteristic. In this paper, we propose a novel automatic patient-level tumor segmentation and classification method, which makes full use of the diagnosis knowledge clues from pathologists. For tumor segmentation, a multi-level view DeepLabV3+ (MLV-DeepLabV3+) is designed to explore the distinguishing features of cell characteristics between tumor and normal tissue. Furthermore, the expert segmentation models are selected and integrated by Pareto-front optimization to imitate the expert consultation to get perfect diagnosis. For wholeslide classification, multi-level magnifications are adaptive checked to focus on the effective features in different magnification. The experimental results demonstrate that our pathologist knowledge-based automatic assessment of whileslide image is effective and robust on the public benchmark dataset.","Title: Attribute-specific Control Units in StyleGAN for Fine-grained Image Manipulation\nYear: 2021\n\nAbstract: ABSTRACTImage manipulation with StyleGAN has been an increasing concern in recent years. Recent works have achieved tremendous success in analyzing several semantic latent spaces to edit the attributes of the generated images. However, due to the limited semantic and spatial manipulation precision in these latent spaces, the existing endeavors are defeated in fine-grained StyleGAN image manipulation, i.e., local attribute translation. To address this issue, we discover attribute-specific control units, which consist of multiple channels of feature maps and modulation styles. Specifically, we collaboratively manipulate the modulation style channels and feature maps in control units rather than individual ones to obtain the semantic and spatial disentangled controls. Furthermore, we propose a simple yet effective method to detect the attribute-specific control units. We move the modulation style along a specific sparse direction vector and replace the filter-wise styles used to compute the feature maps to manipulate these control units. We evaluate our proposed method in various face attribute manipulation tasks. Extensive qualitative and quantitative results demonstrate that our proposed method performs favorably against the state-of-the-art methods. The manipulation results of real images further show the effectiveness of our method.","Title: Network-Load Estimation for K-Repetition Grant-Free Access Enabling Adaptive Resource Allocation Towards QoS Enhancement\nYear: 2021\n\nAbstract: In Ultra-Reliable and Low-Latency Communications (URLLC), K-repetition Grant-Free (GF) access can effectively lower the latency by avoiding the complicated handshake procedures. However, it can hardly achieve both high reliability and millimeter-level latency simultaneously if collisions across users frequently happen. In fact, the collision level mainly replies on whether there are sufficient resources for URLLC compared with the network-load, i.e., the number of active users, which, however, is typically not known by the base station (BS). To solve this problem, we propose the effective network-load estimation schemes for URLLC. In particular, based on access states (success, collision, or empty) of resource blocks across consecutive access slots in a subframe, we derive the multi-slot maximum-likelihood (ML) and single-slot least-squares (LS) estimation schemes. Benefitted from the obtained estimation, we further design the adaptive resource allocation scheme for URLLC. Simulation results corroborate that by exploiting the correlation across multiple access slots, our proposal can achieve more accurate estimation than the baseline scheme. Correspondingly, our adaptive resource allocation schedule offers a way to significantly enhance the delay QoS while assuming reliability at only small cost of a slight increment of total access resources.","Title: Agent-Based Model On Resilience-Oriented Rapid Responses Of Road Networks Under Seismic Hazard\nYear: 2021\n\nAbstract: This paper explores a new pathway towards seismic resilience of Road Networks (RNs) under earthquake hazards, by leveraging post-shock rapid responses as the key to minimize the functionality losses of RNs, especially in the immediate aftermath of earthquakes. Accordingly, an agent-based modelling (ABM) framework is developed to enable the nuanced examination on resilience of earthquake-damaged RNs, when different system repair approaches are considered. In this framework, those different approaches are predicated on the damage level of individual bridges and on the system recovery timeline, i.e. the response to rehabilitation need is considered as a function of the time elapsed from the event. Each approach is represented by a different agent, whose behaviour is shaped by a set of pre-defined behavioural attributes, while the interplay among those agents is also accounted for, during the entirety of post-shock recovery campaigns. To demonstrate its applicability, the ABM framework is applied to a real-world RN across Luchon, France. As shown by the case-study, post-shock rapid responses are found to be a viable strategy to increase the recovery rate of RNs' functionality in the immediate-, and mid-term aftermath of damaging earthquakes, and ultimately, to improve the seismic resilience thereof.","Title: Ciphertext-Only Fault Analysis Of Gift Lightweight Cryptosystem\nYear: 2022\n\nAbstract: Dear editor, The GIFT cryptosystem was proposed by Banik et al.[1]in CHES 2017.It can be widely applied to protect RFID tags and other low-resource devices.It has an SPN struc-ture with a fixed 128-bit key size and two flexible variants of 64-bit and 128-bit block sizes.In simulations,GIFT achieves good performance and surpasses both SIMON and SKINNY[1].In 2013,Fuhr et al.[2]proposed a ciphertext-only fault analysis(CFA)of AES for three types of faults:zero-byte fault,zero-nibble fault,and random-byte fault.Later,Li et al.[3]added new distinguishers(GF,MAP,and GF-SEI)to the LED cryptosystem with high resis-tance to fault injections.Moreover,the CFA in the ran-dom nibble/byte-oriented fault model is more effective and practical.","Title: Bootstrapping ViTs: Towards Liberating Vision Transformers from Pre-training\nYear: 2022\n\nAbstract: Recently, vision Transformers (ViTs) are developing rapidly and starting to challenge the domination of con-volutional neural networks (CNNs) in the realm of computer vision (CV). With the general-purpose Transformer architecture replacing the hard-coded inductive biases of convolution, ViTs have surpassed CNNs, especially in data-sufficient circumstances. However, ViTs are prone to over-fit on small datasets and thus rely on large-scale pre-training, which expends enormous time. In this paper, we strive to liberate ViTs from pre-training by introducing CNNs' in- ductive biases back to ViTs while preserving their network architectures for higher upper bound and setting up more suitable optimization objectives. To begin with, an agent CNN is designed based on the given ViT with inductive bi-ases. Then a bootstrapping training algorithm is proposed to jointly optimize the agent and ViT with weight sharing, during which the ViT learns inductive biases from the intermediate features of the agent. Extensive experiments on CIFAR-10/100 and ImageNet-1k with limited training data have shown encouraging results that the inductive biases help ViTs converge significantly faster and outperform conventional CNNs with even fewer parameters. Our code is publicly available at https://github.com/zhfeing/Bootstrapping-ViTs-pytorch.","Title: Investigating ADHD subtypes in children using temporal dynamics of the electroencephalogram (EEG) microstates\nYear: 2021\n\nAbstract: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder in children, usually categorized as three predominant subtypes, persistent inattention (ADHD-I), hyperactivity-impulsivity (ADHD-111) and a combination of both (ADHD-C). Identifying reliable features to distinguish different subtypes is significant for clinical individualized treatment. In this work, we conducted a two-stage electroencephalogram (EEG) microstate analysis on 54 healthy controls and 107 ADHD children, including 54 ADHD-Is and 53 ADHD-Cs, aiming to examine the dynamic temporal alterations in ADHDs compared to healthy controls (HCs), as well as different EEG signatures between ADHD subtypes. Results demonstrated that the dynamics of resting-state EEG microstates, particularly centering on salience (state C) and frontal-parietal network (state D), were significantly aberrant in ADHDs. Specifically, the occurrence and coverage of state C were decreased in ADHDs (p=0.002; i0.0015), while the duration and contribution of state D were observably increased (p=0.0016; p=0.0001) compared to HCs. Moreover, the transition probability between state A and C was significantly decreased (p=9.85e-7; p=2.33e-7) in ADHDs, but otherwise increased between state B and D (p=1.02e-7; p=1.07e-6). By contrast, remarkable subtype differences were found primarily on the visual network (state B) between ADHD-Is and ADHD-Cs. Specifically, ADHD-Cs have higher occurrence and coverage of state B than ADHD-Is (p=9.35e-5; p=1.51e-8), suggesting these patients more impulsively aimed to open their eyes when asked to keep eyes closed during the data collection. In summary, this work carefully leveraged EEG temporal dynamics to investigate the aberrant microstate features in ADHDs and provided a new window to look into the subtle differences between ADHD subtypes, which may help to assist precision diagnosis in future.","Title: A Self-Supervised Mixed-Curvature Graph Neural Network.\nYear: 2022\n\nAbstract: Graph representation learning received increasing attentions in recent years. Most of the existing methods ignore the complexity of the graph structures and restrict graphs in a single constant-curvature representation space, which is only suitable to particular kinds of graph structure indeed. Additionally, these methods follow the supervised or semi-supervised learning paradigm, and thereby notably limit their deployment on the unlabeled graphs in real applications. To address these aforementioned limitations, we take the first attempt to study the self-supervised graph representation learning in the mixed-curvature spaces. In this paper, we present a novel Self-Supervised Mixed-Curvature Graph Neural Network (SelfMGNN). To capture the complex graph structures, we construct a mixed-curvature space via the Cartesian product of multiple Riemannian component spaces, and design hierarchical attention mechanisms for learning and fusing graph representations across these component spaces. To enable the self-supervised learning, we propose a novel dual contrastive approach. The constructed mixed-curvature space actually provides multiple Riemannian views for the contrastive learning. We introduce a Riemannian projector to reveal these views, and utilize a well-designed Riemannian discriminator for the single-view and cross-view contrastive learning within and across the Riemannian views. Finally, extensive experiments show that SelfMGNN captures the complex graph structures and outperforms state-of-the-art baselines.","Title: Robust and Long-term Monocular Teach and Repeat Navigation using a Single-experience Map\nYear: 2021\n\nAbstract: This paper presents a robust monocular visual teach-and-repeat (VT&R) navigation system for long-term operation in outdoor environments. The approach leverages deep-learned descriptors to deal with the high illumination variance of the real world. In particular, a tailored self-supervised descriptor, DarkPoint, is proposed for autonomous navigation in outdoor environments. We seamlessly integrate the localisation with control, in which proportional-integral control is used to eliminate the visual error with the pitfall of the unknown depth. Consequently, our approach achieves day-to-night navigation using a single-experience map and is able to repeat complex and fast manoeuvres. To verify our approach, we performed a vast array of navigation experiments in various outdoor environments, where both navigation accuracy and robustness of the proposed system are investigated. The experimental results show that our approach is superior to the baseline method with regards to accuracy and robustness.","Title: Monocular Teach-and-Repeat Navigation using a Deep Steering Network with Scale Estimation\nYear: 2021\n\nAbstract: This paper proposes a novel monocular teach-and-repeat navigation system with the capability of scale awareness, i.e. the absolute distance between observation and goal images. It decomposes the navigation task into a sequence of visual servoing sub-tasks to approach consecutive goal/node images in a topological map. To be specific, a novel hybrid model, named deep steering network is proposed to infer the navigation primitives according to the learned local feature and scale for each visual servoing sub-task. A novel architecture, Scale-Transformer, is developed to estimate the absolute scale between the observation and goal image pair from a set of matched deep representations to assist repeating navigation. The experiments demonstrate that our scale-aware teach-and-repeat method achieves satisfying navigation accuracy, and converges faster than the monocular methods without scale correction given an inaccurate initial pose. The proposed network is integrated into an onboard system deployed on a real robot to achieve real-time navigation in a real environment. A demonstration video can be found online: https://youtu.be/ctlwDaMKnHw","Title: A Simple and Robust Spectral Index for Identifying Lodged Maize Using Gaofen1 Satellite Data\nYear: 2022\n\nAbstract: Crop lodging is a major destructive factor for agricultural production. Developing a cost-efficient and accurate method to assess crop lodging is crucial for informing crop management decisions and reducing lodging losses. Satellite remote sensing can provide continuous data on a large scale; however, its utility in detecting lodging crops is limited due to the complexity of lodging events and the unavailability of high spatial and temporal resolution data. Gaofen1 satellite was launched in 2013. The short revisit cycle and wide orbit coverage of the Gaofen1 satellite make it suitable for lodging identification. However, few studies have explored lodging detection using Gaofen1 data, and the operational application of existing approaches over large spatial extents seems to be unrealistic. In this paper, we discuss the identification method of lodged maize and explore the potential of using Gaofen1 data. An analysis of the spectral features after maize lodging revealed that reflectance increased significantly in all bands, compared to non-lodged maize. A spectral sum index was proposed to distinguish lodged and non-lodged maize. Two study areas were considered: Zhaodong City in Heilongjiang Province and Ningjiang District in Jilin Province. The results of the identified lodged maize from the Gaofen1 data were validated based on three methods: first, ground sample points exhibited the overall accuracies of 92.86% and 88.24% for Zhaodong City and Ningjiang District, respectively; second, the cross-comparison differences of 1.01% for Zhaodong City and 1.13% for Ningjiang District were obtained, compared to the results acquired from the finer-resolution Planet data; and third, the identified results from Gaofen1 data and those from farmer survey questionnaires were found to be consistent. The validation results indicate that the proposed index is promising, and the Gaofen1 data have the potential for rapid lodging monitoring.","Title: Knowledge Distillation via Constrained Variational Inference.\nYear: 2022\n\nAbstract: Knowledge distillation has been used to capture the knowledge of a teacher model and distill it into a student model with some desirable characteristics such as being smaller, more efficient, or more generalizable. In this paper, we propose a framework for distilling the knowledge of a powerful discriminative model such as a neural network into commonly used graphical models known to be more interpretable (e.g., topic models, autoregressive Hidden Markov Models). Posterior of latent variables in these graphical models (e.g., topic proportions in topic models) is often used as feature representation for predictive tasks. However, these posterior-derived features are known to have poor predictive performance compared to the features learned via purely discriminative approaches. Our framework constrains variational inference for posterior variables in graphical models with a similarity preserving constraint. This constraint distills the knowledge of the discriminative model into the graphical model by ensuring that input pairs with (dis)similar representation in the teacher model also have (dis)similar representation in the student model. By adding this constraint to the variational inference scheme, we guide the graphical model to be a reasonable density model for the data while having predictive features which are as close as possible to those of a discriminative model. To make our framework applicable to a wide range of graphical models, we build upon the Automatic Differentiation Variational Inference (ADVI), a black-box inference framework for graphical models. We demonstrate the effectiveness of our framework on two real-world tasks of disease subtyping and disease trajectory modeling.","Title: Style Transformer for Image Inversion and Editing\nYear: 2022\n\nAbstract: Existing GAN inversion methods fail to provide latent codes for reliable reconstruction and flexible editing simultaneously. This paper presents a transformer-based image inversion and editing model for pretrained StyleGAN which is not only with less distortions, but also of high quality and flexibility for editing. The proposed model employs a CNN encoder to provide multi-scale image features as keys and values. Meanwhile it regards the style code to be determined for different layers of the generator as queries. It first initializes query tokens as learnable parameters and maps them into W+ space. Then the multi-stage alternate self-and cross-attention are utilized, updating queries with the purpose of inverting the input by the generator. Moreover, based on the inverted code, we investigate the reference-and label-based attribute editing through a pretrained latent classifier, and achieve flexible image-to-image translation with high quality results. Extensive experiments are carried out, showing better performances on both inversion and editing tasks within StyleGAN. Codes are available at https://github.com/sapphire497/style-transformer.","Title: QS-Attn: Query-Selected Attention for Contrastive Learning in I2I Translation\nYear: 2022\n\nAbstract: Unpaired image-to-image (I2I) translation often requires to maximize the mutual information between the source and the translated images across different domains, which is critical for the generator to keep the source content and prevent it from unnecessary modifications. The self-supervised contrastive learning has already been successfully applied in the I2I. By constraining features from the same location to be closer than those from different ones, it implicitly ensures the result to take content from the source. However, previous work uses the features from random locations to impose the constraint, which may not be appropriate since some locations contain less information of source domain. Moreover, the feature itself does not reflect the relation with others. This paper deals with these problems by intentionally selecting significant anchor points for contrastive learning. We design a query-selected attention (QS-Attn) module, which compares feature distances in the source domain, giving an attention matrix with a probability distribution in each row. Then we select queries according to their measurement of significance, computed from the distribution. The selected ones are regarded as anchors for contrastive loss. At the same time, the reduced attention matrix is employed to route features in both domains, so that source relations maintain in the synthesis. We validate our proposed method in three different I2I datasets, showing that it increases the image quality with-out adding learnable parameters. Codes are available at https://github.com/sapphire497/query-selected-attention.","Title: DiriE: Knowledge Graph Embedding with Dirichlet Distribution\nYear: 2022\n\nAbstract: ABSTRACT Knowledge graph embedding aims to learn representations of entities and relations in low-dimensional space. Recently, extensive studies combine the characteristics of knowledge graphs with different geometric spaces, including Euclidean space, complex space, hyperbolic space and others, which achieves significant progress in representation learning. However, existing methods are subject to at least one of the following limitations: 1) ignoring the uncertainty, 2) incapability of complex relation patterns. To address the above issues simultaneously, we propose a novel model named DiriE, which embeds entities as Dirichlet distributions and relations as multinomial distributions. DiriE employs Bayesian inference to measure the relations between entities and learns binary embeddings of knowledge graphs for modeling complex relation patterns. Additionally, we propose a two-step negative triple generation method that generates negative triples of both entities and relations. We conduct a solid theoretical analysis to demonstrate the effectiveness and robustness of our method, including the expressiveness of complex relation patterns and the ability to model uncertainty. Furthermore, extensive experiments show that our method outperforms state-of-the-art methods in link prediction on benchmark datasets.","Title: Hierarchical Amortized GAN for 3D High Resolution Medical Image Synthesis\nYear: 2022\n\nAbstract: Generative Adversarial Networks (GAN) have many potential medical imaging applications, including data augmentation, domain adaptation, and model explanation. Due to the limited memory of Graphical Processing Units (GPUs), most current 3D GAN models are trained on low-resolution medical images, these models either cannot scale to high-resolution or are prone to patchy artifacts. In this work, we propose a novel end-to-end GAN architecture that can generate high-resolution 3D images. We achieve this goal by using different configurations between training and inference. During training, we adopt a hierarchical structure that simultaneously generates a low-resolution version of the image and a randomly selected sub-volume of the high-resolution image. The hierarchical design has two advantages: First, the memory demand for training on high-resolution images is amortized among sub-volumes. Furthermore, anchoring the high-resolution sub-volumes to a single low-resolution image ensures anatomical consistency between sub-volumes. During inference, our model can directly generate full high-resolution images. We also incorporate an encoder with a similar hierarchical structure into the model to extract features from the images. Experiments on 3D thorax CT and brain MRI demonstrate that our approach outperforms state of the art in image generation. We also demonstrate clinical applications of the proposed model in data augmentation and clinical-relevant feature extraction.","Title: Generalized ESO based stable predictive tracking control for micro gas turbine cogeneration system\nYear: 2022\n\nAbstract: •A novel ESO-SPTC combining ESO and SPTC is developed without destroying the overall optimality.•A new discrete-time generalized ESO is proposed to surmount higher-order disturbances.•In SPTC, the infinite horizon inputs fully satisfy the amplitude and rate constraints.•The ESO-SPTC effectively solves the control problem of the micro gas turbine cogeneration system.","Title: Rescaling-Assisted Super-Resolution for Medium-Low Resolution Remote Sensing Ship Detection\nYear: 2022\n\nAbstract: Medium-low resolution (M-LR) remote sensing ship detection is a challenging problem due to the small target sizes and insufficient appearance information. Although image super resolution (SR) has become a popular solution in recent years, the ability of image SR is limited since much information is lost in input images. Inspired by the powerful information embedding ability of the encoder in image rescaling, in this paper, we introduce image rescaling to guide the training of image SR. Specifically, we add an adaption module before the SR network, and use the pre-trained rescaling network to guide the optimization of the adaption module. In this way, more information is embedded in the adapted M-LR images, and the subsequent SR module can utilize more information to achieve better performance. Extensive experimental results demonstrate the effectiveness of our method on image SR. More importantly, our method can be used as a pre-processing approach to improve the detection performance.","Title: Efficient Superpixel Generation for Polarimetric SAR Images with Cross-Iteration and Hexagonal Initialization\nYear: 2022\n\nAbstract: Clustering-based methods of polarimetric synthetic aperture radar (PolSAR) image superpixel generation are popular due to their feasibility and parameter controllability. However, these methods pay more attention to improving boundary adherence and are usually time-consuming to generate satisfactory superpixels. To address this issue, a novel cross-iteration strategy is proposed to integrate various advantages of different distances with higher computational efficiency for the first time. Therefore, the revised Wishart distance (RWD), which has better boundary adherence but is time-consuming, is first integrated with the geodesic distance (GD), which has higher efficiency and more regular shape, to form a comprehensive similarity measure via the cross-iteration strategy. This similarity measure is then utilized alternately in the local clustering process according to the difference between two consecutive ratios of the current number of unstable pixels to the total number of unstable pixels, to achieve a lower computational burden and competitive accuracy for superpixel generation. Furthermore, hexagonal initialization is adopted to further reduce the complexity of searching pixels for relabelling in the local regions. Extensive experiments conducted on the AIRSAR, RADARSAT-2 and simulated data sets demonstrate that the proposed method exhibits higher computational efficiency and a more regular shape, resulting in a smooth representation of land cover in homogeneous regions and better-preserved details in heterogeneous regions.","Title: Climatological Aspects of Active Fires in Northeastern China and Their Relationship to Land Cover\nYear: 2022\n\nAbstract: Biomass burning (BB) is a driving force for heavy haze in northeastern China (NEC) and shows distinct seasonal features. However, little is known about its climatological aspects, which are important for regional BB management and understanding BB effects on climate and environment. Here, the climatological characteristics of active fires and their dependence on land cover in NEC were studied using Moderate Resolution Imaging Spectroradiometer (MODIS) products. Moreover, the influence of meteorological factors on fire activities was explored. The number of fires was found to have increased significantly from 2003 to 2018; and the annual total FRP (FRPtot) showed a generally consistent variation with fire counts. However, the mean fire radiative power for each spot (FRPmean) decreased. Fire activity showed distinctive seasonal variations. Most fires and intense burning events occurred in spring and autumn. Spatially, fires were mainly concentrated in cropland areas in plains, where the frequency of fires increased significantly, especially in spring and autumn. The annual percentage of agricultural fires increased from 34% in 2003 to over 60% after 2008 and the FRPtot of croplands increased from 12% to over 55%. Fires in forests, savannas, and grasslands tended to be associated with higher FRPmean than those in croplands. Analysis indicated that the increasing fire count in NEC is mainly caused by agricultural fires. Although the decreasing FRPmean represents an effective management of BB in recent years, high fire counts and FRPtot in croplands indicate that the crop residue burning cannot be simply banned and a need instead for effective applications. More efforts should be made on clean utilization of straw. The accumulation of dry biomass, high temperature, and low humidity, and weak precipitation are conducive to the fire activities. This study provides a comprehensive analysis of BB in NEC and provides a reference for regional BB management and control.","Title: Cross Attention Based Style Distribution for Controllable Person Image Synthesis.\nYear: 2022\n\nAbstract: Controllable person image synthesis task enables a wide range of applications through explicit control over body pose and appearance. In this paper, we propose a cross attention based style distribution module that computes between the source semantic styles and target pose for pose transfer. The module intentionally selects the style represented by each semantic and distributes them according to the target pose. The attention matrix in cross attention expresses the dynamic similarities between the target pose and the source styles for all semantics. Therefore, it can be utilized to route the color and texture from the source image, and is further constrained by the target parsing map to achieve a clearer objective. At the same time, to encode the source appearance accurately, the self attention among different semantic styles is also added. The effectiveness of our model is validated quantitatively and qualitatively on pose transfer and virtual try-on tasks. Codes are available at https://github.com/xyzhouo/CASD.","Title: User Behavior Pre-training for Online Fraud Detection\nYear: 2022\n\nAbstract: The outbreak of COVID-19 burgeons newborn services on online platforms and simultaneously buoys multifarious online fraud activities. Due to the rapid technological and commercial innovation that opens up an ever-expanding set of products, the insufficient labeling data renders existing supervised or semi-supervised fraud detection models ineffective in these emerging services. However, the ever accumulated user behavioral data on online platforms might be helpful in improving the performance of fraud detection on newborn services. To this end, in this paper, we propose to pre-train user behavior sequences, which consist of orderly arranged actions, from the large-scale unlabeled data sources for online fraud detection. Recent studies illustrate accurate extraction of user intentions~(formed by consecutive actions) in behavioral sequences can propel improvements in the performance of online fraud detection. By anatomizing the characteristic of online fraud activities, we devise a model named UB-PTM that learns knowledge of fraud activities by three agent tasks at different granularities, i.e., action, intention, and sequence levels, from large-scale unlabeled data. Extensive experiments on three downstream transaction and user-level online fraud detection tasks demonstrate that our UB-PTM is able to outperform the state-of-the-art designing for specific tasks.","Title: A Self-supervised Riemannian GNN with Time Varying Curvature for Temporal Graph Learning\nYear: 2022\n\nAbstract: ABSTRACTRepresentation learning on temporal graphs has drawn considerable research attention owing to its fundamental importance in a wide spectrum of real-world applications. Though a number of studies succeed in obtaining time-dependent representations, it still faces significant challenges. On the one hand, most of the existing methods restrict the embedding space with a certain curvature. However, the underlying geometry in fact shifts among the positive curvature hyperspherical, zero curvature Euclidean and negative curvature hyperbolic spaces in the evolvement over time. On the other hand, these methods usually require abundant labels to learn temporal representations, and thereby notably limit their wide use in the unlabeled graphs of the real applications. To bridge this gap, we make the first attempt to study the problem of self-supervised temporal graph representation learning in the general Riemannian space, supporting the time-varying curvature to shift among hyperspherical, Euclidean and hyperbolic spaces. In this paper, we present a novel self-supervised Riemannian graph neural network (SelfℛGNN). Specifically, we design a curvature-varying Riemannian GNN with a theoretically grounded time encoding, and formulate a functional curvature over time to model the evolvement shifting among the positive, zero and negative curvature spaces. To enable the self-supervised learning, we propose a novel reweighting self-contrastive approach, exploring the Riemannian space itself without augmentation, and propose an edge-based self-supervised curvature learning with the Ricci curvature. Extensive experiments show the superiority of SelfRGNN, and moreover, the case study shows the time-varying curvature of temporal graph in reality.","Title: Explore the Correlation between Environmental Factors and the Spatial Distribution of Property Crime\nYear: 2022\n\nAbstract: Comprehensively understanding the factors influencing crime is a prerequisite for preventing and combating crime. Although some studies have investigated the relationship between environmental factors and property crime, the interaction between factors was not fully considered in these studies, and the explanation of complex factors may be insufficient. This paper explored the influence of environmental factors on property crime using factor regression and factor interaction based on data from the central city of Lanzhou, China. Our findings showed that: (1) The distribution of crime cases showed the pattern of a local multi-center. Shop density, hotel density, entertainment density and house price were the four dominant environmental drivers of property crime; (2) The relationship between the light intensity and property crime had different correlation explanations in temporal projection and spatial projection. There was a normal distribution curve between the number of property crimes and the Price-to-Earnings Ratio (PE Ratio) of the community house price; and (3) The results of the factor interaction indicated that the effect of all factors on crime showed a two-factor enhancement. As an important catalyst, shop density had the strongest interaction with other factors. Shop density gradient influenced the degree of interpretation of spatial heterogeneity of property crime.","Title: Transmit Antenna Placement Based on Graph Theory for MIMO Radar Detection\nYear: 2022\n\nAbstract: Optimal antenna placement for target detection using multiple-input multiple-output (MIMO) radar system with widely separated antennas is studied in this paper. Considering the problem of placing a limited number of transmit antennas in a given space to maximize the detection performance, an optimization problem is formulated with the output signal-to-noise ratio (SNR) indicator as the performance metric. The initial problem is a nonlinear integer programming problem, and with the increase of the number of antennas, the computational complexity using traditional methods can be huge. In this paper, we discretize the feasible space into several grid points and employ graph theory to handle the problem. The antennas and grid points can be viewed as vertices in a bipartite graph, so that the antenna placement problem can be viewed as seeking for a proper matching between two vertex sets. We transform the problem into a stable matching (SM) problem and a maximum weighted matching (MWM) problem respectively, and propose Gale-Shapley (GS)-based and Kuhn-Munkres (KM)-based algorithms to deal with them with polynomial complexity. Numerical examples are provided to evaluate the effectiveness of the proposed methods.","Title: Robust Tuning of Active Disturbance Rejection Controller for Time-Delay Systems With Application to a Factual Electrostatic Precipitator\nYear: 2022\n\nAbstract: Active disturbance rejection control (ADRC) shows great potential in mitigating various uncertainties of both motion and process control. However, the controller tuning is generally time-consuming, and the resulting performance highly depends on the individual experience. This brief aims to develop a standard robust tuning rule for a time-delayed ADRC structure based on a class of time-delay systems represented by a second-order plus time delay (SOPTD) model. The bandwidth parameters of the controller and the observer are, respectively, scaled in terms of SOPTD parameters. The resulting dimensionless parameters enable exhaustive evaluation of the robustness. Compared to the traditional metrics, it reveals that delay margin is the dominant robustness index for the controller tuning. A dominated form of the robust tuning rule is recommended, and the stability condition of a closed-loop system is given. Simulations and experiments are conducted on a factual electrostatic precipitator in the coal-fired power plant to validate the efficacy of the proposed tuning rule.","Title: Stability Analysis and Performance Improvement of Power Sharing Control in Islanded Microgrids\nYear: 2022\n\nAbstract: Due to the requirement of synchronism and power sharing, droop control and its variations have become one essential component for distributed generator (DG)-powered microgrids. However, the power sharing accuracy and system stability margin may be threatened by the randomness from the load demand and renewable generation. In this paper, a dynamic stability analysis is first performed on a DG-powered microgrid through a produced system frequency response model (SFR). The results point out that (i) the critical system eigenvalues directly vary with the system operating condition; (ii) a fixed-gain power sharing control is prone to be less damped and loses stability easily under some operating conditions. Then, the heuristic adaptive dynamic programming (HDP) strategy is used for power sharing control with the benefit of adapting to real-time disturbances and uncertainties. Through Lyapunov theorem, stability analysis is provided to demonstrate the reliability of the HDP-based power sharing control in islanded microgrids. Finally, simulation tests verify the analysis results and demonstrate the favorable performance of the HDP-based power sharing control under uncertain load disturbances."],"string":"[\n \"Title: Reciprocally Benefited Spectrum Access Scheme With Joint Power and Subcarrier Allocation in a Software-Defined Network.\\nYear: 2015\\n\\nAbstract: Aiming at realizing ubiquitous spectrum access and improving the spectrum efficiency in a software-defined network, in this paper, we adopt the concept of cognitive radio and propose a joint subcarrier and power allocation (JSPA) scheme for reciprocally benefited spectrum access with secondary users (SUs) cooperating with primary users (PUs). In our proposed JSPA scheme, SUs adopt the decode-and-f...\",\n \"Title: Real time gaze estimation with a consumer depth camera\\nYear: 2015\\n\\nAbstract: Simple-setup real-time gaze estimation system using only a consumer depth camera.3D model based gaze estimation method allowing free head movement.Iris center localization method able to handle relatively low-quality eye images.Simple system calibration easy to be carried out for nonprofessional users. Existing eye-gaze-tracking systems typically require multiple infrared (IR) lights and high-quality cameras to achieve good performance and robustness against head movement. This requirement limits the systems' potential for broader applications. In this paper, we present a low-cost, non-intrusive, simple-setup gaze estimation system that can estimate the gaze direction under free head movement. In particular, the proposed system only uses a consumer depth camera (Kinect sensor) positioned at a distance from the subject. We develop a simple procedure to calibrate the geometric relationship between the screen and the camera, and subject-specific parameters. A parameterized iris model is then used to locate the center of the iris for gaze feature extraction, which can handle low-quality eye images. Finally, the gaze direction is determined based on a 3D geometric eye model, where the head movement and deviation of the visual axis from the optical axis are taken into consideration. Experimental results indicate that the system can estimate gaze with an accuracy of 1.4-2.7¿ and is robust against large head movements. Two real-time human-computer interaction (HCI) applications are presented to demonstrate the potential of the proposed system for wide applications.\",\n \"Title: Background modeling and its evaluation for complex scenes\\nYear: 2015\\n\\nAbstract: We present a new approach for modeling background in complex scenes that contain unpredicted motions caused e.g. by wind over water surface, in tree branches, or over the grass. The background model of each pixel is defined based on the observation of its spatial neighborhood in a recent history, and includes up to K 1$K \\\\ge 1$ modes, which defines the frequently appeared patterns at the given pixel position in the color space, ranked in decreasing order of occurrence frequency. Foreground regions can then be detected by comparing the intensity of an observed pixel to the high frequency modes of its background model. Experiments show that our spatial-temporal background model is superior to traditional related algorithms in cases for which a pixel encounters modes that are frequent in the spatial neighborhood without being frequent enough in the actual pixel position. As an additional contribution, our paper also proposes an original assessment method, which has the advantage of avoiding the use of costly handmade ground truth sequences of foreground objects silhouettes.\",\n \"Title: Fountain-Coding Aided Strategy for Secure Cooperative Transmission in Industrial Wireless Sensor Networks.\\nYear: 2016\\n\\nAbstract: Cooperative relaying communications is an efficient paradigm for end-to-end data delivery in industrial wireless sensor networks. However, due to the broadcast nature of radio propagation, it is challenging to guarantee the secrecy of cooperative transmissions under eavesdropping attacks. To deal with this issue, a fountain-coding aided relaying scheme is proposed in this paper, for which all the ...\",\n \"Title: Noncontact Vital Sign Detection based on Stepwise Atomic Norm Minimization\\nYear: 2015\\n\\nAbstract: Noncontact techniques for detecting vital signs have attracted great interest due to the benefits shown in medical monitoring and military applications. A rapid remote evaluation on physiological signal frequencies is needed in search and rescue operations as well as intensive care. However, the presence of respiration harmonics causes aliasing problems to heart-rate estimation, especially when th...\",\n \"Title: Redundant-coded radial and neighbor star pattern identification algorithm\\nYear: 2015\\n\\nAbstract: Aimed at solving the lost-in-space (LIS) problem, a robust star pattern identification algorithm is presented. The neighbor star pattern is introduced to increase separating ability and stabilization of star patterns and reduce the effects of magnitude noise. Redundant coding for radial and neighbor star patterns is proposed to more effectively remove the effects of position noise. Binary bit strings are used for storing the redundant code to reduce the size of the on-board database. A similar score measurement is proposed on the basis of shift and logical AND operations to quickly implement the star's initial match. The final match results are obtained using a strategy of searching for the longest matching chain. The algorithm is evaluated with synthesized and real star images. The identification rates of this algorithm are 97.98% with standard deviations of position noises of 1 pixel and 94.96% with standard deviations of magnitude noises of 0.646 Mv. Moreover, the identification rate is 77.12% when there are only four stars in the field of view (FOV). The algorithm obtains an average identification rate of 96.96% from real star images.\",\n \"Title: Interference-controlled D2D routing aided by knowledge extraction at cellular infrastructure towards ubiquitous CPS\\nYear: 2015\\n\\nAbstract: Device-to-device (D2D) networks underlaying cellular networks are widely recognized as one of the major approaches for ubiquitous information acquisition and exchange, which features the future cyber-physical systems (CPSs). In this paper, we propose the interference-controlled D2D routing designs underlaying cellular networks, i.e. sharing/reusing the cellular spectrum, to support multi-hop D2D transmissions and thus enhancing the flexibility of CPS. The unique feature and challenge for this task include threefolds. First, the huge density of device nodes in future cellular networks yields huge amount of information to process. Second, as device nodes in cellular networks do not maintain the routing table, the route selection via low-complexity knowledge-extraction approach over huge amount of information needs to be performed by the base station (BS). Third, the interference generated by reusing cellular spectrum needs to be thoroughly controlled. To address these issues, we in this work consider two D2D networking scenarios that allow D2D users to share the uplink and downlink spectrum of cellular networks, respectively. Our objective for routing is hop-count minimization such that the delay and power consumptions can be decreased. In particular, we propose a maximum rate towards destination (MR-D) routing algorithm for the scenario sharing uplink spectrum and a MR-D advanced (MR-DA) routing algorithm for the scenario sharing downlink spectrum, respectively. Both algorithms have low computational complexity and thus meaningful for practical systems. Furthermore, our routing designs can avoid the violation of tolerable interferences to cellular users as well as to fulfil the rate requirement of D2D services. Also conducted are abundant simulation evaluations to demonstrate the advantages of our proposed schemes as compared to the baseline schemes including the farthest neighbour routing and closest to destination routing scheme.\",\n \"Title: A Vision System Based On Tof 3d Imaging Technology Applied To Robotic Citrus Harvesting\\nYear: 2015\\n\\nAbstract: This study was conducted to develop a fast machine vision system based on TOF (time of flight) three-dimensional (3D) imaging technology for automatic citrus recognition and location. Supported algorithms were specifically developed and programmed for image acquisition and processing. An adaptive filter coupled between partial differential equations filter and shock filter was presented to remove noise and sharpen edges efficiently. Image analysis algorithms integrated both range and amplitude information to generate regions of interest and parameters that are characteristic or very likely to belong to spherical objects. The three-dimensional position of the fruit and radius are obtained after the recognition stages. The total classification results showed that approximately 81.8% were detected and false detection occurred only once. On the whole, the process of imaging, recognition and location consumes less than 50ms/fruit.\",\n \"Title: Precoder-and-receiver design scheme for multi-user coordinated multi-point in LTE-A and fifth generation systems.\\nYear: 2016\\n\\nAbstract: Coordinated multi-point (CoMP) techniques can be utilised in several wireless systems, such as LTE-A and fifth generation. However, inter-user interferences (IEIs) and intra-user interferences (IAIs) may degrade the quality of service in joint transmission (JT), CoMP systems. To suppress these interferences, the authors design an interference mitigation scheme via interference alignment (IA) and c...\",\n \"Title: New optimisation model and fuzzy adaptive weighted genetic algorithm for hazardous material transportation\\nYear: 2012\\n\\nAbstract: On the basis of analysing the unusual objectives of hazardous material transportation HMT, a new multi-objective optimisation model for hazardous material transportation MOM-HMT is established, which takes into account transportation risk, operation time, the number of sensitive population, risks fairness and multi-batch transportation simultaneously. Then a fuzzy adaptive weighted genetic algorithm FAWGA is set up to solve the MOM-HMT by designing priority-based encoding method, partial matching crossover, fuzzy logic control and adaptive weighted assignment mechanism. Finally, the model and algorithm are applied to a real case. The study results show the new model is feasible and the improved genetic algorithm is more effective than the standard genetic algorithm and the improved ant colony algorithm.\",\n \"Title: Prediction based interference management and distributed trajectory regulation in amorphous cells\\nYear: 2015\\n\\nAbstract: The amorphous cells have emerged as a new paradigm to meet the fast increasing wireless capacity and coverage demands. Compared with the traditional cellular networks with hexagon-based deployments, the amorphous cells support mobile base stations (MBS) to form dynamic cell topologies, which can adapt to the group-movement behaviors of network loads. These amorphous cells are required to be self-organized so as to facilitate distributed coordination between MBSs, whereby the operational costs can be effectively reduced. Moreover, the management of cochannel interferences needs to take MBSs??? movement into account, which is the new challenge not encountered in traditional cellular networks. In this paper, we propose a distributed trajectory regulation algorithm aiming at enhancing the reliability of communications for multiple mobile-host (MH) groups, while not violating the required travel time budgets. For this purpose, we jointly consider the prediction of channel conflicts across MBSs???, the channel collision costs, and cooperative channel allocation for trajectory control. Simulation evaluations show that our algorithm can well balance the reliability and travel time. The simulation results also demonstrate the reduction of failure rate for incoming calls compared with the conventional approach, especially when the network load is high.\",\n \"Title: Accurate garment surface analysis using an active stereo robot head with application to dual-arm flattening\\nYear: 2015\\n\\nAbstract: We present a visually guided, dual-arm, industrial robot system that is capable of autonomously flattening garments by means of a novel visual perception pipeline that fully interprets high-quality RGB-D images of a clothing scene based on an active stereo robot head. A segmented clothing range map is B-Spline smoothed prior to being parsed by means of shape and topology analysis into ‘wrinkle’ structures. The length, width and height of each wrinkle is used to quantify the topology of each wrinkle and thereby rank wrinkles by size such that a greedy algorithm can identify the largest wrinkle present. A flattening plan optimised for the largest detected wrinkle is formulated based on dual-arm manipulation. We report the validation of our autonomous flattening behaviour and observe that dual-arm flattening requires significantly fewer manipulation iterations than single-arm flattening. Our experimental results also reveal that the flattening process is heavily influenced by the quality of the RGB-D sensor: use of a custom off-the-shelf high-resolution stereo-based sensor system outperformed a commercial low-resolution kinect-like camera in terms of required flattening iterations.\",\n \"Title: A Novel Data Mining Method on Falling Detection and Daily Activities Recognition\\nYear: 2015\\n\\nAbstract: With the intensification of aging population, a growing number of elderly people have to live alone due to domestic and social reasons. Falling becomes one of the most crucial factors in threatening the elderly's lives, which is always difficult to be detected as it is instantaneous and easy to be confused with other motions, such as lying down. In this paper, a new method is proposed for accurate falling detection and activities recognition. It applies hierarchical classifiers to the time series data set including eleven activities of daily living (ADLs), collected by four wearable sensors. The new method combines two machine learning algorithms, performs concrete analysis on the original outcome and then obtains several scarcely-confused groups separately. The experiment indicates that the new method improves the accuracy of classification to a larger extent, reached to more than 90%. Furthermore, the matched algorithm for applying these classifiers, called Hierarchical Classifier Algorithm (HCA), is proposed as well.\",\n \"Title: Cooperative jamming with untrusted SUs for secure communication of two-hop primary system\\nYear: 2015\\n\\nAbstract: This paper investigates the problem of secure communications of the two-hop primary system with the cooperative jamming of the untrusted secondary system. The secondary system is untrusted for the primary system and willing to eavesdrop on the primary signal. In addition, the secondary system is also willing to provide friendly jamming to increase the secure rate of the primary system in reward for being allowed to share the licensed spectrum. Specifically, the cooperative communication is implemented into two slots which correspond to the transmission of the first and second hops of the primary system, respectively. In each slot, part of the slot is allocated for the primary information transmission. Simultaneously, a secondary user (SU) is selected to broadcast jamming signal to protect the secure communication of the primary users (PU) against the other untrusted SUs. Then, the remaining time of the slot is allocated for the secondary transmission. To maximize the transmission rate of the secondary system under the constraint of the target secure rate requirement of the primary system, we optimally select two jamming SUs and determine the time parameters in each slot. SUs' average transmit rate and the lower bound on PUs' secure outage probability are derived. Simulation results demonstrate the performance superiority of our developed strategy over conventional secure communication schemes in terms of PUs' secure outage probability and SUs' average transmission rate.\",\n \"Title: Robust Precoder-And-Receiver Design For Interference Suppression And Channel Uncertainty Restraint In Multi-User Comp System\\nYear: 2015\\n\\nAbstract: Inter-user interferences (IEIs) and intra-user interferences (IAIs) may degrade the quality-of-service in JT (joint transmission)-CoMP (coordinated multi-point) systems. Interference alignment (IA) with prefect channel state information (CSI) can efficiently mitigate these interferences. However, in realistic systems, the effect of IA is obviously decreased via channel uncertainty with channel estimation and quantization errors. In this case, we propose a novelly robust precoder-and-receiver design scheme with IA (NRIA) for interference suppression and channel uncertainty restraint. In the NRIA, we first utilize precoding method to suppress the IEIs to each user generated by the users' actually acquired channels. Second, the receiver of each user is devised to alleviate the impact of IAI and channel uncertainty. Unlike the existing MU-MIMO schemes which introduce the statistical or bounded information of the above errors, the NRIA is a local scheme for JT and contains the instantaneous information of channel uncertainty. The instantaneous information can be abstracted through installing and sending special transmit signals from base stations to users without exorbitant overhead. The NRIA doesn't include any iteration, moreover, it can suppress interference and improve robustness compared with just using statistical or bounded information of channel uncertainty.\",\n \"Title: Statistical security model and power adaptation over wireless fading channels\\nYear: 2015\\n\\nAbstract: Secrecy capacity is the widely-used metric to evaluate the capability of wireless channels in delivering messages with the assurance of perfect security as well as reliability. However, with the proliferation and diversification of wireless services, there have been urgent needs in fine-grained and decoupled security metrics towards future mobile communications. In this paper, we propose a statistical model to characterize the finegrained security level, while evaluating the secrecy independently from the reliability. Specifically, we model the data eavesdropping process by a queuing system, where the data arrival represents the information overheard by the eavesdropper. The departure process is modeled by a constant leaving rate, implying that the eavesdropped data will become useless after certain time. The eavesdropper has to accumulate sufficient amount of data for successful decipherment. We further define the novel statistical security metric via a queue-length bound and a bound-violation probability threshold. As long as the violation probability is below the specified threshold, the statistical security is guaranteed. This model can fit diverse services well by tuning corresponding parameters for the statistical security metric. Following the statistical security model, we formulate the security-driven power adaptation problem for throughput maximization over fading channels. Applying asymptotic queuing analyses and effective bandwidth theory, we solve the problem and obtain a set of power control schemes under diverse system parameters. Simulation evaluations are also presented to demonstrate the superiority of our scheme over the baseline schemes.\",\n \"Title: Joint Secure Beamforming And User Selection For Multi-User Miso Systems With Confidential Messages\\nYear: 2015\\n\\nAbstract: In this paper, we propose a joint secure beamforming and user selection (J-SBS) scheme to improve the secrecy sum rate in multi-user multiple-input-single-output (MISO) broadcast channels with confidential messages (BCC). The user selection mechanism can bring about multi-user diversity which may be also exploited by eavesdroppers in multi-user MISO sysytem. We show how the system secrecy sum rate under the semi-orthogonal user selection (SUS) algorithm will be limited if users collude with each other. To solve this problem, based on the prediction that selected users have mutual orthogonal beamformers, we characterize a new expression of the secrecy rate. By optimizing the secrecy rate we then derive a corresponding suboptimal secrecy beamformer for each user to reduce the interference and information leakage. Moreover, we apply SUS to select suitable beamformers matching with the prediction. Simulation results show the effectiveness of our proposed method.\",\n \"Title: Information Security Enhancement With Actual Access Statuses Of Users In The Multi-User System\\nYear: 2015\\n\\nAbstract: In the new generation wireless communication systems, when multiple users are served, information security among them should be considered to protect each user's privacy. In this case, physical layer security techniques can be adopted for this mutual confidence problem. Unlike other traditional physical layer security methods, the proposed scheme improves secrecy rate with the information of users' access statuses (i.e., being served or idle), and it is denoted as SRT-AS. In the SRT-AS, appropriate parameters expressing users' actual access statuses are introduced, and an adaptive transmitter and receiver design strategy is used to increase security. It can be found that no iterative process is included in the SRT-AS, moreover, performance analysis and simulation results illustrate that the SRT-AS is feasible for the multi-user system.\",\n \"Title: Estimation Based Adaptive Acb Scheme For M2m Communications\\nYear: 2015\\n\\nAbstract: It is a critical challenge to support massive access of devices in a short period in machine-to-machine (M2M) communications. In this paper, we propose a estimation based adaptive Access Class Barring (ACB) scheme to improve the scalability of M2M networks. First, we propose a simple estimation scheme to estimate the network loads. Then we obtain two functions which are the relationship of ACB's barring factor (the parameter of access probability) and network loads to maximize the system throughput. According to the estimation and the obtained functions, eNB changes ACB barring factor dynamically to adapt to the network load conditions. At the same time, we summarize the boundedness of the adaptive scheme. Finally, simulation results illustrate that our scheme can increase the system throughput and reduce access delay obviously.\",\n \"Title: Enhancing Wireless Security Against Reactive Jamming Attacks: A Game-Theoretical Framework\\nYear: 2015\\n\\nAbstract: Reactive jamming, which launches jamming attacks when the legitimate transmissions are detected, is one of the most serious security threats in wireless communications. In this paper, we investigate the wireless security issue in the presence of a reactive jammer from a game-theoretical perspective. Specifically, the legitimate user and jammer respectively aim at maximize and minimize the expected legitimate transmission rate, which is formulated as a zero-sum game. For the jammer, we consider the imperfection in detection and analyze the optimal jamming strategy by the joint optimization over detection time and jamming power. For the legitimate user, the transmit power is optimized by achieving the tradeoff between obtained transmission rate and the probability to be accurately detected and thus jammed by its adversary. The Nash equilibrium is characterized by the best-response playing between the legitimate user and reactive jammer. Finally, we present simulation results to verify the effectiveness of our proposed approach.\",\n \"Title: Semisupervised Classification Of Sar Images By Maximum Margin Neural Networks Method\\nYear: 2015\\n\\nAbstract: The proposed method is based on neural networks by modeling the data marginal distribution with the graph Laplacian built with both labeled and unlabeled samples, at the same time, optimizing neural networks layers in a single process, back-propagating the gradient of a Maximum Margin based objective function. Therefore, the proposed approach gives rise to an operational classifier, as opposed to previously presented semi-supervised scenarios. Results demonstrate the improved classification accuracy and scalability of this approach on SAR image classification problems.\",\n \"Title: Multispectral Image Fusion Based On Laplacian Pyramid Decomposition With Immune Co-Evolutionary Optimization\\nYear: 2015\\n\\nAbstract: In this paper, a new multispectral image fusion algorithm is proposed by considering the abundant directional information and complex high frequency of source images. In this algorithm, Laplacian pyramid (LP) is constructed to filter the source images to obtain initial fusion coefficients, then an evolution computation idea, immune co-evolutionary optimization algorithm, is introduced into the image fusion to optimize the fusion coefficients. The optimized fusion coefficients can make better fusion result. Simulation experiments of clearly demonstrate the superiority of this proposed algorithm by comparing with conventional wavelets systems: the information entropy (IE) values keep at a similar level, the average grads (AG) values are higher, the standard deviation (STD) values increases 1.2 averagely, and the time efficiency increases averagely about 51 %.\",\n \"Title: Dt-Cwt-Based Improved Baq For Anti-Saturation Sar Raw Data Compression\\nYear: 2015\\n\\nAbstract: In this paper, an anti-saturation raw data compressing algorithm for Synthetic Aperture Radar (SAR) based on Dual-Tree Complex Wavelet Transform (DT-CWT) and improved Block Adaptive quantization (BAQ) is proposed. The DT-CWT has approximate shift-invariant and good directional selectivity. The improved BAQ rebuild data keeps the saturation signal. We apply DT-CWT to fractional saturation SAR raw data. The result put into improved BAQ quantizer. Experiment shows this method has a high compression rate and Signal to Noise Ratio (SNR).\",\n \"Title: EYEWATCHME- 3D hand and object tracking for inside out activity analysis\\nYear: 2009\\n\\nAbstract: This paper investigates the \\\"inside-out\\\" recognition of everyday manipulation tasks using a gaze-directed camera, which is a camera that actively directs at the visual attention focus of the person wearing the camera. We present EYEWATCHME, an integrated vision and state estimation system that at the same time tracks the positions and the poses of the acting hands, the pose that the manipulated object, and the pose of the observing camera. Taken together, EYEWATCHME provides comprehensive data for learning predictive models of vision-guided manipulation that include the objects people are attending, the interaction of attention and reaching/grasping, and the segmentation of reaching and grasping using visual attention as evidence. Key technical contributions of this paper include an ego view hand tracking system that estimates 27 DOF hand poses. The hand tracking system is capable of detecting hands and estimating their poses despite substantial selfocclusion caused by the hand and occlusions caused by the manipulated object. EYEWATCHME can also cope with blurred images that are caused by rapid eye movements. The second key contribution is the of the integrated activity recognition system that simultaneously tracks the attention of the person, the hand poses, and the poses of the manipulated objects in terms of a global scene coordinates. We demonstrate the operation of EYEWATCHME in the context of kitchen tasks including filling a cup with water. © 2009 IEEE.\",\n \"Title: Cyclic-Shifting Based Sequential Cooperative Spectrum Sensing Strategy for Multi-Channel Cognitive Radio Networks.\\nYear: 2015\\n\\nAbstract: Traditional multi-channel cooperative spectrum sensing (CSS) scheme schedules a group of cognitive users (CU) to sense a particular channel in any given sensing slot, which means that the same sensing sequence pattern is shared by all CUs in the group. Although the sensing accuracy can be improved, the energy consumption will correspondingly increase. In order to reduce the energy consumption without loss of the sensing accuracy, we in this paper propose a cyclic-shifting based sequential CSS strategy for multi-channel cognitive networks (CN). Specifically, instead of employing the common shared sensing sequence pattern, our proposed strategy assigns a unique cyclic-shifting based sensing sequence for each CU, such that different channels will be sensed simultaneously in any given sensing slot. Moreover, if the decision for a particular channel can be made by current sensing information, the channel will not be sensed in the following sensing slots. Theoretical analysis shows that our proposed strategy can efficiently reduce the number of both sensing slots and reporting slots consumed for each channel and achieve the same probabilities of detection and false-alarm as the traditional CSS scheme. This implies that the energy efficiency of the system can be improved while maintaining the sensing accuracy undegraded. Simulation results are also provided to demonstrate the superiority of our proposed strategy as compared to the existing scheme.\",\n \"Title: Antenna Tilt Assignment for Three-Dimensional Beamforming in Multiuser Systems.\\nYear: 2015\\n\\nAbstract: In recent years, many approaches have been introduced in next generation (5G) wireless cellular networks in response to the demands for higher data rates and broader coverage. In this paper, a novel downlink three-dimensional (3D) beamforming scheme is proposed for the 5G multiuser multiple-input multiple-output (MU-MIMO) system. This scheme separates beams in the so-called elevation domain via base station (BS) antenna tilt assignment, with the objective of reducing inter-user interference. The key to this scheme is controlling the vertical radiation pattern of BS antennas, which is realized by more efficient use of a two-dimensional (2D) planar antenna array. Moreover, we give the optimal solution of 3D beamforming to maximize the users average data rate, including adjustments of the antenna array and the corresponding multiuser selection algorithm. This can be used as a systematic framework for any given 3D scenario to mitigate inter-user interference. Our simulation results demonstrate the performance benefits in terms of transmission rate in comparison with traditional schemes.\",\n \"Title: Joint Battery-Buffer Sustainable Guarantees in Energy-Harvesting Enabled Wireless Networks.\\nYear: 2015\\n\\nAbstract: In light of the drastically-increasing demands on ubiquitous information acquisition and exchange, battery-powered devices are playing a more critical role in wireless networking, which inspires and expedites the development of energy-harvesting techniques. The sustainability requirements for such devices include two mutual-impacting dimensions: energy supply avoiding battery outage and stable transmissions avoiding buffer overflow. We in this paper propose a power-and-rate adaption scheme subject to the constraints on buffer-overflow probability and battery-outage probability in energy-harvesting enabled networks, which aims at maximizing the system throughput. The two probability constraints address the statistical assurance for the two-dimensional sustainability, which is suitable to dealing with the highly unpredictable energy-harvesting and channel fading statuses. Specifically, by applying the asymptotic queuing analyses to data-transmission and energy-harvesting processes, we can characterize both of the battery-outage and buffer-overflow probabilities via the effective-capacity/-bandwidth theories. Then, we formulate the effective-capacity optimization problem, which maximizes the sustainable throughput while complying with the statistical buffer-overflow and battery-outage constraints, and solve for the optimal power-adaptation scheme. We also conduct abundant simulations to evaluate our scheme's performances, demonstrate the superiority of our proposed scheme over existing baseline schemes, as well as study the impact of sustainability requirements on the performances.\",\n \"Title: AF-Based CSI Feedback for User Selection in Multi-User MIMO Systems.\\nYear: 2015\\n\\nAbstract: In this paper, we propose a joint amplify-and-forward (AF)-based channel estimation and user selection (J-ACES) scheme for multi-user MIMO (MU-MIMO) systems. Firstly, without channel state information (CSI) quantization, the transmitter estimates the downlink CSI for each receiver by adopting AF-based CSI feedback mechanism, in which the receiver amplifies and feeds back its own received downlink pilot symbols to the transmitter. An analytic user normalized mean square error (UNMSE) characterization of the uplink channel estimation and a lower bound of UNMSE for the downlink channel estimation are respectively derived and verified by Monte Carlo simulations. We show how the performance of UNMSE is influenced by the uplink and downlink pilot signal to noise ratio (SNR). Secondly, we obtain a corresponding suboptimal beamformer and estimated Signal to Interference Plus Noise Ratio (SINR) for each receiver to minimize the influence of estimation error on the subsequent user selection based on semi-orthogonal user selection (SUS). Finally, a mechanism that each selected receiver is informed of all the selected receiver beamformers to adopt the minimum mean square error (MMSE) detector is performed for further reducing the error caused by the uncertainty of the user selection. Simulation results show that the proposed scheme can improve the system spectral efficiency and has robust spectral efficiency gain even under the condition that the uplink pilot SNR is 20dB lower than the downlink pilot SNR, as compared to Quasi-MMSE Weight (QMW) scheme.\",\n \"Title: Securing Wireless Transmission against Reactive Jamming: A Stackelberg Game Framework.\\nYear: 2015\\n\\nAbstract: Reactive jamming, which performs jamming attacks on condition of detecting the legitimate transmissions, is widely considered as one of the most serious security challenges in wireless communications. In this paper, we tackle the reactive jamming issue from a novel yet realistic perspective - the jammer may not always be able to accurately detect the legitimate transmissions, which in turn, can be exploited by the legitimate user to enhance security. In accordance with the detection-then-jamming characteristic of reactive jamming, we formulate the transmitting-jamming problem within a Stackelberg game framework, where the legitimate user takes action first, followed by the reactive jammer. To optimize its own utility, the legitimate user needs to determine the transmission strategy by elaborately achieving the tradeoff between the signal-to-interference-plus-noise ratio (SINR) and the probability to be accurately detected and thus jammed by its adversary. The investigation on Stackelberg equilibrium provides the solution to the game model. Furthermore, we consider the more practical situation that the legitimate user has only incomplete knowledge regarding its adversary and analyze the corresponding impact on the game and equilibrium. Simulation results demonstrate significant performance superiority in terms of secure legitimate transmissions compared with the classical approach.\",\n \"Title: Context weight considered for implicit feature extracting\\nYear: 2015\\n\\nAbstract: Researchers have been devoted to using context to extract implicit features. However, little concerns have been given to the situation that not all the contexts are meaningful. To solve this problem, we present a new method to evaluate the contribution of the contexts for extracting. We build an improved Co-occurrence matrix that containing the distance between an opinion word and different contexts. And then a LDA topic model is used to get the topic probability of the opinion word. The weight of context can be obtained by using cosine similarity in the improved Co-occurrence matrix and LDA topic model. We design a formula to extract implicit features with the consideration of context and topic. Experiments have showed that our method provides higher accuracy in extracting the implicit features.\",\n \"Title: User cooperation analysis under eavesdropping attack: A game theory perspective\\nYear: 2014\\n\\nAbstract: In this paper, the user cooperation behaviors under eavesdropping attack are analyzed through game theory. Considering the physical layer security, we prove that the conventional cooperation scheme actually deteriorates the secrecy performance compared to the direct transmission, given that the eavesdropper has a better channel condition to the users than the destination. In this case, the necessary condition of the cooperation that the users should obtain additional utilities from the cooperation is not satisfied, which makes the users have no incentive to participate in the cooperation game. In order to motivate users, an adaptive cooperation scheme is designed to improve the secrecy performance even if the eavesdropping channel is superior to the destination's channel, and it is also observed that the mutual cooperation is one of the Nash equilibriums. We further exploit the Stackelberg game with a punishment mechanism to make the mutual cooperation as the unique Nash equilibrium.\",\n \"Title: Poster: Enabling Hands-free Drawing on WiFi Devices\\nYear: 2015\\n\\nAbstract: We present the high-level design of WiDraw, the first 3D hand motion tracking system using COTS WiFi cards, proposed in [3]. WiDraw can track hand gestures without a priori learning or requiring the user to hold any hardware. It can be implemented on existing mobile devices using only a software patch. WiDraw exploits the Angle-of-Arrival values of incomingWiFi signals at aWiFi device and enables hand trajectory tracking in both LOS and NLOS scenarios. WiDraw's high tracking accuracy allows the users to send arbitrary input to their WiFi devices, opening up a whole new class of applications in human-computer interactions.\",\n \"Title: Improving Connectivity, Coverage, and Capacity in 60 GHz Indoor WLANs Using Relays\\nYear: 2015\\n\\nAbstract: 60 GHz technology, standardized by IEEE 802.11ad, has emerged as an alternative to 2.4/5 GHz legacy WiFi for building multi-Gigabit general purpose home/enterprise WLANs. However, limited range and high vulnerability to blockage of millimeter-wave (mmWave) links can severely affect WLAN performance. These problems coupled with long re-connection time for a broken link pose a major challenge to the realization of 60 GHz WLANs. In this work, we look at the relay architecture defined in the 802.11ad standard as a solution to these issues and propose extensions to it for achieving gains in both WLAN coverage and capacity.\",\n \"Title: WiDraw: Enabling Hands-free Drawing in the Air on Commodity WiFi Devices\\nYear: 2015\\n\\nAbstract: This paper demonstrates that it is possible to leverage WiFi signals from commodity mobile devices to enable hands-free drawing in the air. While prior solutions require the user to hold a wireless transmitter, or require custom wireless hardware, or can only determine a pre-defined set of hand gestures, this paper introduces WiDraw, the first hand motion tracking system using commodity WiFi cards, and without any user wearables. WiDraw harnesses the Angle-of-Arrival values of incoming wireless signals at the mobile device to track the user's hand trajectory. We utilize the intuition that whenever the user's hand occludes a signal coming from a certain direction, the signal strength of the angle representing the same direction will experience a drop. Our software prototype using commodity wireless cards can track the user's hand with a median error lower than 5 cm. We use WiDraw to implement an in-air handwriting application that allows the user to draw letters, words, and sentences, and achieves a mean word recognition accuracy of 91%.\",\n \"Title: Towards Motion-Aware Wireless LANs Using PHY Layer Information\\nYear: 2015\\n\\nAbstract: The increasing popularity of WiFi brings new challenges in the design of wireless protocols but at the same time creates exciting opportunities for novel ways of exploiting WiFi technology in a variety of applications. On one hand, the smaller form factor of today's WiFi devices allows WiFi users to access wireless networks under mobility, calling for new, mobility-aware wireless protocols that are able to sustain high performance, on the other hand, the ubiquity of WiFi devices has recently raised interest in extending WiFi's capabilities beyond communication, e.g., for human-computer interaction. In this paper, we demonstrate that it is possible to enable fine-grained human motion detection on commodity WiFi devices by exploiting PHY layer information exposed by today's WiFi chipsets. We propose two motion detection techniques for two different application scenarios and explore their benefits on protocol performance and human-device interaction, respectively.\",\n \"Title: Optimization of Postal Distribution Network Based on Rendezvous with Heterogeneous Vehicles and Capacity Constraints\\nYear: 2015\\n\\nAbstract: High unloaded ratio of trucks is one of the key factors that incur high costs of mail transportation in China's postal network. How to reduce unnecessary deadhead kilometers of trucks is worthy of being researched. In this paper, we take heterogeneous trucks and facility capacity into consideration of optimizing the postal express line network using Rendezvous driving pattern of trucks. A mixed integer non-linear programming model is built and a corresponding mixed genetic algorithm is developed to solve the model. A numerical simulation is also designed to verify the validity of the model and the algorithm developed in this research. Through a comparison of Rendezvous and direct travel mode, some insights of Rendezvous are presented. (C) 2015 The Authors. Published by Elsevier B.V.\",\n \"Title: Dynamic Allocation of RACH Resource for Clustered M2M Communications in LTE Networks.\\nYear: 2015\\n\\nAbstract: In this paper, we propose a dynamic allocation scheme of random access channel (RACH) resource for clustered machine-to-machine (M2M) communications, in which delay-sensitive services coexist with delay-tolerant ones. Our scheme aims at alleviating the overload and congestion of machine-type (MTC) communication as well as satisfying both delay-sensitive and delay-tolerant services. Specifically, the operation of our protocol includes three aspects. First, in order to make full use of the preamble resources controlled by the Enhanced Node B (eNB), our proposed scheme adopts a two-cluster networking, where MTC devices are divided into two clusters based on their requirements on delay. Second, we develop the dynamic allocation scheme to partition the available preambles for each cluster under the condition of guaranteeing the preferable number of successful devices. Third, the devices belonging to different clusters adopt the access class barring (ACB) mechanism respectively. Simulation results show that our proposed scheme realizes the remarkable increase in improving the access success probability and achieve performance improvement in reducing access delay.\",\n \"Title: Interference Cancellation Based Transmission Strategy Using Primary Arq For Cooperative Crns\\nYear: 2015\\n\\nAbstract: Aiming at efficient utilizing the licensed spectrum, in this paper, we develop an interference cancellation based transmission strategy (ICTS) for the cooperative cognitive radio networks (CRN) which will take advantage of the opportunities that arise during the primary automatic repeat requests (ARQ) and cancel the primary interference in both the primary initial transmission and retransmission slots. Simultaneously, the secondary system will cooperate with the primary system by supporting its outage quality-of-service (QoS) requirement to speedup the primary transmission and acquire more interferencefree spectrum opportunities. Specifically, in the primary initial transmission slot, the secondary users (SU) will transmit in the underlay mode. In addition, SUs try to decode the primary signal to cancel the primary interference and overhear the primary ARQ signal. In the retransmission slot, SUs can cancel the primary interference directly when the primary signal is successfully decoded in the initial slot or utilize the primary information redundancy to cancel the interference. With statistical channel state information (CSI), SUs can calculate their interference cancellation probabilities in both slots and derive their average transmission rate. To maximize SUs' average transmission rate while meeting PUs outage QoS requirement, we formulate the optimization problem and efficiently allocate SUs transmit power. The closed-form expressions of the average transmission rates for both PUs and SUs are derived. Furthermore, SUs' upper bound symbol error probability (SEP) and PUs' SEP are derived. Simulation results demonstrate the performance superiority of our developed ICTS over conventional ARQ-based transmission strategies in terms of SUs' average throughput and PUs' outage probability and SEP.\",\n \"Title: Massive Access Control Aided by Knowledge-Extraction for Co-Existing Periodic and Random Services over Wireless Clinical Networks.\\nYear: 2016\\n\\nAbstract: The prosperity of e-health is boosted by fast development of medical devices with wireless communications capability such as wearable devices, tiny sensors, monitoring equipments, etc., which are randomly distributed in clinic environments. The drastically-increasing population of such devices imposes new challenges on the limited wireless resources. To relieve this problem, key knowledge needs to be extracted from massive connection attempts dispersed in the air towards efficient access control. In this paper, a hybrid periodic-random massive access (HPRMA) scheme for wireless clinical networks employing ultra-narrow band (UNB) techniques is proposed. In particular, the proposed scheme towards accommodating a large population of devices include the following new features. On one hand, it can dynamically adjust the resource allocated for coexisting periodic and random services based on the traffic load learned from signal collision status. On the other hand, the resource allocation within periodic services is thoroughly designed to simultaneously align with the timing requests of differentiated services. Abundant simulation results are also presented to demonstrate the superiority of the proposed HPRMA scheme over baseline schemes including time-division multiple access (TDMA) and random access approach, in terms of channel utilization efficiency, packet drop ratio, etc., for the support of massive devices' services.\",\n \"Title: Initial position estimation strategy for a surface permanent magnet synchronous motor used in hybrid electric vehicles.\\nYear: 2016\\n\\nAbstract: A novel nonlinear model for surface permanent magnet synchronous motors (SPMSMs) is adopted to estimate the initial rotor position for hybrid electric vehicles (HEVs). Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis (FEA) model is presented first. Hybrid injection of a static voltage vector (SVV) superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive.\",\n \"Title: Physical layer security based on real interference alignment in K-user MIMO Y wiretap channels\\nYear: 2016\\n\\nAbstract: In this paper, we study the information-theoretical security of the K-user MIMO Y wiretap Gaaussian channels and deduce the lower bounds of the secure degrees of freedom (SDOF). Due to the different receiving links of the eavesdropper, we propose two MIMO Y wiretap models which are called Broadcast Wiretap Channel (BWC) and Multi-access Broadcast Wiretap Channel (MBWC), respectively. Each legitimate user equipped with M antennas intends to transmit independent signals via an intermediate amplify-and-forward (AF) relay with N antennas. Besides, there exists an eavesdropper with Ne antennas close to the K users (K ≥ 3). Based on the asymptotic real interference alignment and the structured cooperative jamming, the security of the MIMO Y wiretap channels can be guaranteed. From the asymptotic analysis, we can find that a lower bound of the sum SDOF in BWC is K/4. While in the MBWC model, since the relay working in the full duplex mode broadcasts cooperative jamming signals to all the other nodes especially to the eavesdropper, the lower bound of sum SDOF is K\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\n-3K/4(K-1), which is altered along with the number of users.\",\n \"Title: Samer Plus : Balancing Short Term Throughput And Long Term Stability In Cognitive Radio Mesh Networks\\nYear: 2016\\n\\nAbstract: A large number of routing protocols for Cognitive radio networks (CRNs) have been proposed recently, each based on different design goals, and evaluated in different scenarios, under different assumptions. In our previous work, we conducted the first extensive empirical performance study of routing protocols for CRNs - Coolest Path, SAMER, and CRP - under the same realistic set of assumptions. Our study revealed that SAMER significantly outperforms the other protocols under low primary user activity but its performance degrades under high PU activity.In this work, we introduce an enhanced version of SAMER (SAMER+) that performs consistently well in both low and high PU activity scenarios. The core of SAMER+ is a new path metric that balances short term throughput and long term path stability. We evaluate SAMER+ using extensive simulations and compare it against SAMER and Coolest Path. Our results show that SAMER+ significantly outperforms both protocols in a variety of scenarios.\",\n \"Title: On Achievable Secrecy Rate By Noise Aggregation Over Wireless Fading Channels\\nYear: 2016\\n\\nAbstract: Noise aggregation is an efficient way of aggregating the inherent noises introduced during wireless transmissions over multiple channels to degrade the eavesdropper's channel quality. While the performance of channel aggregation has not been thoroughly studied over wireless fading channels, we in this paper concentrating on analyses of its achievable average secrecy rate with emphasis on binary symmetric channel (BSC), whose crossover probability is a time-varying process. The advantage of noise aggregation over traditional transmission in fading environments is demonstrated by our analyses and simulations. Simulation results show that the noise aggregation scheme can achieve a remarkable increase in terms of average secrecy rate even if the eavesdropper has better average channel quality than the legitimate receiver.\",\n \"Title: Active jamming for multi-user information security improvement with the access statuses of users.\\nYear: 2016\\n\\nAbstract: We propose a novel physical layer scheme for improving multiple users' information security e.g., vehicle devises and mobile terminals in the next-generation communication systems. Owing to the limitation of service node's antennas, not all users can be concurrently served. Therefore, the node only provides services for some chosen users in a certain time. On the basis of this premise, in our scheme, the access status of each user is involved. With the information of access status, the node devises transmitters to increase the served users' transmission rates and decrease the possibility of each idle user's signal interception. Furthermore, the node executes active jamming according to the realistic situation of this multi-user network for confusing the idle users/potential eavesdroppers. In addition, with the gradually mature applications of full-duplex techniques for the terminals, each user can also implement active jamming in the full-duplex mode to interfere with the potential eavesdroppers. It is seen that our scheme is linear without iteration, and performance analysis and simulation results illustrate that it is feasible for multi-user security enhancement. Copyright © 2016 John Wiley & Sons, Ltd.\",\n \"Title: Robot Vision Architecture for Autonomous Clothes Manipulation.\\nYear: 2016\\n\\nAbstract: This paper presents a novel robot vision architecture for perceiving generic 3D clothes configurations. Our architecture is hierarchically structured, starting from low-level curvatures, across mid-level geometric shapes u0026 topology descriptions; and finally approaching high-level semantic surface structure descriptions. We demonstrate our robot vision architecture in a customised dual-arm industrial robot with our self-designed, off-the-self stereo vision system, carrying out autonomous grasping and dual-arm flattening. It is worth noting that the proposed dual-arm flattening approach is unique among the state-of-the-art robot autonomous system, which is the major contribution of this paper. The experimental results show that the proposed dual-arm flattening using stereo vision system remarkably outperforms the single-arm flattening and widely-cited Kinect-based sensing system for dexterous manipulation tasks. In addition, the proposed grasping approach achieves satisfactory performance on grasping various kind of garments, verifying the capability of proposed visual perception architecture to be adapted to more than one clothing manipulation tasks.\",\n \"Title: Detecting Anomalous User Behavior Using an Extended Isolation Forest Algorithm: An Enterprise Case Study.\\nYear: 2016\\n\\nAbstract: Anomalous user behavior detection is the core component of many information security systems, such as intrusion detection, insider threat detection and authentication systems. Anomalous behavior will raise an alarm to the system administrator and can be further combined with other information to determine whether it constitutes an unauthorised or malicious use of a resource. This paper presents an anomalous user behaviour detection framework that applies an extended version of Isolation Forest algorithm. Our method is fast and scalable and does not require example anomalies in the training data set. We apply our method to an enterprise dataset. The experimental results show that the system is able to isolate anomalous instances from the baseline user model using a single feature or combined features.\",\n \"Title: Two Birds With One Stone: Towards Secure and Interference-Free D2D Transmissions via Constellation Rotation.\\nYear: 2016\\n\\nAbstract: This paper studies the cooperative device-to-device (D2D) transmissions in cellular networks, where two D2D users communicate bidirectionally with each other and simultaneously serve as relays to assist the two-way transmissions between two cellular users. For this scenario, both cellular and D2D links share the same spectrum, thus creating mutual interference. In addition to that, a security prob...\",\n \"Title: Control of a Class of Industrial Processes With Time Delay Based on a Modified Uncertainty and Disturbance Estimator.\\nYear: 2016\\n\\nAbstract: The control algorithm based on the uncertainty and disturbance estimator (UDE) is considered as an efficient control strategy that has attracted much attention recently. However, it cannot be directly applied to the widely existing industrial processes with time delay. To extend its applicability, the UDE control algorithm is modified so that it can be applied to stable, integrating, and unstable ...\",\n \"Title: Dynamic RACH Partition for Massive Access of Differentiated M2M Services.\\nYear: 2016\\n\\nAbstract: In machine-to-machine (M2M) networks, a key challenge is to overcome the overload problem caused by random access requests from massive machine-type communication (MTC) devices. When differentiated services coexist, such as delay-sensitive and delay-tolerant services, the problem becomes more complicated and challenging. This is because delay-sensitive services often use more aggressive policies, and thus, delay-tolerant services get much fewer chances to access the network. To conquer the problem, we propose an efficient mechanism for massive access control over differentiated M2M services, including delay-sensitive and delay-tolerant services. Specifically, based on the traffic loads of the two types of services, the proposed scheme dynamically partitions and allocates the random access channel (RACH) resource to each type of services. The RACH partition strategy is thoroughly optimized to increase the access performances of M2M networks. Analyses and simulation demonstrate the effectiveness of our design. The proposed scheme can outperform the baseline access class barring (ACB) scheme, which ignores service types in access control, in terms of access success probability and the average access delay.\",\n \"Title: Development and Application of a Next Generation Air Sensor Network for the Hong Kong Marathon 2015 Air Quality Monitoring.\\nYear: 2016\\n\\nAbstract: This study presents the development and evaluation of a next generation air monitoring system with both laboratory and field tests. A multi-parameter algorithm was used to correct for the impact of environmental conditions on the electrochemical sensors for carbon monoxide (CO) and nitrogen dioxide (NO2) pollutants. The field evaluation in an urban roadside environment in comparison to designated monitors showed good agreement with measurement error within 5% of the pollutant concentrations. Multiple sets of the developed system were then deployed in the Hong Kong Marathon 2015 forming a sensor-based network along the marathon route. Real-time air pollution concentration data were wirelessly transmitted and the Air Quality Health Index (AQHI) for the Green Marathon was calculated, which were broadcast to the public on an hourly basis. The route-specific sensor network showed somewhat different pollutant patterns than routine air monitoring, indicating the immediate impact of traffic control during the marathon on the roadside air quality. The study is one of the first applications of a next generation sensor network in international sport events, and it demonstrated the usefulness of the emerging sensor-based air monitoring technology in rapid network deployment to supplement existing air monitoring.\",\n \"Title: Security Enhanced Via Dynamic Fountain Code Design For Wireless Delivery\\nYear: 2016\\n\\nAbstract: Guaranteeing the secure delivery is a critical yet challenging issue in wireless transmission. In this paper, a secure delivery scheme that utilizing the dynamic fountain code design is proposed. Using fountain-coded transmission, the transmitter continuously sends fountain packets until the legitimate receiver successfully recovers the original data from a sufficient number of fountain packets. Secure delivery can be guaranteed if the eavesdropper overhears inadequate fountain packets to recover the original data. Inspired by this insight, we propose a fountain-encoded scheme in transmitter which adopts the feedback from the legitimate receiver as the encoding motivation. By dynamically adjusting the fountain-encoded mechanism based on the message fed back from legitimate user, the proposed scheme is beneficial to enhance the decoding rate of legitimate receiver. Further, we analyse the performance for the intercept probability as well as the transmission efficiency of the transmitter. Simulation results confirm our analytical results and demonstrate that, compared with the counterparts, our proposed scheme more effectively guarantees secure wireless delivery with lower intercept probability and higher transmission efficiency.\",\n \"Title: Advanced fault-tolerant current control of five-phase PMSM for mining applications.\\nYear: 2016\\n\\nAbstract: The next big change in mining technology is associated with using more power dense motors, such as permanent magnet synchronous motors (PMSM). For added robustness and fault tolerance, multiphase PMSM can be recommended. Focus of this paper is development of an advanced current control scheme for five-phase PMSM under normal conditions and one-phase open-fault. While traditional linear controllers can cope well with current reference tracking in the healthy motor conditions, but post fault operation involves unmodelled dynamics, which significantly reduces the effectiveness of linear controllers. The proposed non-linear control scheme is based on decoupled fault motor model and sliding mode control (SMC). It is capable of providing constant d and q axis current and constant back-EMFs, even if the motor is missing one phase. With this approach the faulty motor has a smooth output speed profile. This makes it efficient and suitable for demanding drive applications, such as mining machinery. Feasibility of the proposed control strategy is experimentally verified on a FPGAIDCS based five-phase PMSM drive.\",\n \"Title: Hybrid Secure Beamforming And Vehicle Selection Using Hierarchical Agglomerative Clustering For C-Ran-Based Vehicle-To-Infrastructure Communications In Vehicular Cyber-Physical Systems\\nYear: 2016\\n\\nAbstract: The architecture of C-RAN-based soft-defined vehicular networks can support increasing demands of various applications in the future vehicular cyber-physical systems, but lacks strong and practical security-enhancing mechanisms in the physical layer. In this article, we propose a hybrid beamforming and vehicle-selection framework for vehicle-to-infrastructure communications to broadcast high-speed confidential messages. A one-dimensional roadway scenario having multiple lanes is considered, and the concept of secure region and interference-selection region is, respectively, developed for each roadside unit. We formulate an optimization problem of maximizing secrecy sumrate with the constraint of orthogonality-based vehicle selection. The original problem is then divided into two subproblems subtly. In terms of the first subproblem, we, by exploiting the orthogonality assumption, obtain a corresponding secure beamformer for each vehicle located in the secure region to reduce the interference and confidential information leakage. Based on secure beamformers, the second subproblem is changed to be a vehicle-selection problem, which is then solved by adopting hierarchical agglomerative clustering method and implemented by two proposed novel algorithms blending vehicle selection with beamformer generation. Simulation results verify the effectiveness of the proposed algorithms in the respect of secrecy sumrate compared with the conventional zero-forcing beamforming using semi-orthogonal user selection algorithms. Furthermore, simulations show how our proposed algorithms resist against eavesdropping from collusive vehicles located in the same secure region by flexibly altering the size of secure region and interference-selection according to the traffic density.\",\n \"Title: Micromotion Feature Extraction and Distinguishing of Space Group Targets.\\nYear: 2017\\n\\nAbstract: Traditional micro-Doppler (m-D) analysis theories largely focus on isolated targets, making these theories difficult to utilize in monitoring and recognizing space group targets. This letter proposes an algorithm for separating ballistic group targets based on the extraction of micromotion features. Modeling the ballistic targets as cone-cylinder models, the skeleton extraction method in morpholog...\",\n \"Title: Backup sourcing with capacity reservation under uncertain disruption risk and minimum order quantity.\\nYear: 2017\\n\\nAbstract: We develop a backup sourcing strategy through capacity reservation contract under supply disruptions.The buyer's optimal sourcing decisions as well as the backup supplier's optimal reservation price are derived.Different disruption levels are integrated and their impacts are investigated.The effects of flexible backup capacity with MOQ constraint on the contract terms are examined.We show that the both the buyer and the backup supplier may benefit from the MOQ constraints. Ample evidence has confirmed the importance of backup sourcing when disruption of the major supply source is inevitable. The decisions associated with how to work with the backup supplier to ensure backup or emergency supply when the primary source experiences shortfall have received a great deal of attention. We study a capacity reservation contract between a buyer and a backup supplier when there is uncertainty about the major supplier's disruption risks. Additionally, we consider the constraint that requires the buyer to order either none or at least a minimum order quantity in the case of contingent sourcing. By committing to such backup contracts, the buyer seeks to lower its contingent purchasing cost and to ensure the availability of merchandise in the presence of risks. The involving players' optimal decisions are investigated theoretically and the impacts of the key parameters and special scenarios are assessed numerically. The study contributes to the literature by providing a better understanding of how to use a capacity reservation contract as a vehicle to build long-term relationship in backup sourcing and of the impacts of disruption uncertainty and contingent supply availability.\",\n \"Title: Cooperative Privacy Preserving Scheme for Downlink Transmission in Multiuser Relay Networks.\\nYear: 2017\\n\\nAbstract: This paper studies the privacy-preserving for downlink transmission in multiuser relay networks, where a source communicates with multiple users via a relay employing the amplify-and-forward protocol. Within any scheduling unit, only one user (desired user) is chosen for data reception, and the other users (undesired users) are viewed as potential eavesdroppers due to the broadcast nature of wireless medium. To prevent information leakage, we propose a physical-layer cooperative privacy preserving scheme, whose key idea is to schedule a cooperating user in addition to the desired user to deliver artificial noise (AN). By exploiting the characteristics of channels, the cooperating user carefully designs the AN transmitted during two time slots such that the AN can be canceled out at the desired user, but cannot be removed at the undesired users. As a result, the end-to-end signal-to-noise-ratio of any undesired user is heavily degraded, while that of the desired user is not seriously affected, thus preserving the data confidentiality of the desired user. To maximize the instantaneous secrecy rate, an opportunistic user selection criterion is developed. The lower bound of the ergodic secrecy rate (ESR) as well as the approximate upper bound of the secrecy outage probability is derived. The asymptotic performance of ESR is also analyzed via extreme value theory. Furthermore, to motivate users with heterogeneous channel conditions to participate in cooperation and guarantee the fairness among users, a user-grouping-based selection method is proposed. To evaluate the performance of this method, a novel concept called system fairness factor is introduced and studied. Theoretical analysis and simulation results show that, thanks to the proposed cooperative privacy preserving mechanism, the system ESR grows with the increasing number of users, and much higher secrecy rate and lower secrecy outage probability can be achieved compared with the existing schemes in the literature.\",\n \"Title: Reciprocally-Benefited Secure Transmission for Spectrum Sensing-Based Cognitive Radio Sensor Networks.\\nYear: 2016\\n\\nAbstract: The rapid proliferation of independently-designed and -deployed wireless sensor networks extremely crowds the wireless spectrum and promotes the emergence of cognitive radio sensor networks (CRSN). In CRSN, the sensor node (SN) can make full use of the unutilized licensed spectrum, and the spectrum efficiency is greatly improved. However, inevitable spectrum sensing errors will adversely interfere with the primary transmission, which may result in primary transmission outage. To compensate the adverse effect of spectrum sensing errors, we propose a reciprocally-benefited secure transmission strategy, in which SN's interference to the eavesdropper is employed to protect the primary confidential messages while the CRSN is also rewarded with a loose spectrum sensing error probability constraint. Specifically, according to the spectrum sensing results and primary users' activities, there are four system states in this strategy. For each state, we analyze the primary secrecy rate and the SN's transmission rate by taking into account the spectrum sensing errors. Then, the SN's transmit power is optimally allocated for each state so that the average transmission rate of CRSN is maximized under the constraint of the primary maximum permitted secrecy outage probability. In addition, the performance tradeoff between the transmission rate of CRSN and the primary secrecy outage probability is investigated. Moreover, we analyze the primary secrecy rate for the asymptotic scenarios and derive the closed-form expression of the SN's transmission outage probability. Simulation results show that: (1) the performance of the SN's average throughput in the proposed strategy outperforms the conventional overlay strategy; (2) both the primary network and CRSN benefit from the proposed strategy.\",\n \"Title: Experimental Evaluation of WiFi Active Power/Energy Consumption Models for Smartphones.\\nYear: 2017\\n\\nAbstract: We conduct an extensive experimental evaluation of a class of WiFi active power/energy consumption models for smartphones that are based on parameters readily available to the upper layers of the protocol stack. We first consider a number of parameters used by previous models and show their limitations. We then focus on a recent approach modeling the active power consumption as a function of the application layer throughput. We study the properties of a previously proposed throughput-based model in relation to other parameters such as the packet size and/or the transport layer protocol, and we evaluate its accuracy under a variety of scenarios that have not been considered in previous studies. Our results show that the model works well in a number of scenarios, with both 802.11n- and 802.11ac-equipped smartphones, and its accuracy can be largely improved with the knowledge of transport layer protocol and packet size. However, such knowledge makes the model more complex and results in largely reduced accuracy in high throughput settings or on hardware different from the one that was used for training. We further discuss a few practical issues related to the measurement and modeling methodology.\",\n \"Title: Road curve fitting by multi-resolution analysis\\nYear: 2016\\n\\nAbstract: In this paper, we propose a new method for road curve fitting in urban environment based on multi-resolution analysis. The main technical contributions of the proposed method are the reconstructed approximation on the basis of the wavelet decomposition structure for curve fitting and the de-noising via the wavelet coefficients thresholding. The carried out experimental tests show promising results in a series of continuous driving images, validating our suggested method can fit the road curve effectively and computational efficiently.\",\n \"Title: Security Protection Over Wireless Fading Channels By Exploiting Frequency Selectivity\\nYear: 2016\\n\\nAbstract: Secure wireless communication has always been a hot research topic due to the vulnerabilities associated with wireless channel Physical layer aspects to secure wireless communication, based on the information-theoretic security and signal processing methods have gained much recognition over the last. decade. Specifically, artificial noise (AN) methods are assumed to be good means for providing security against potential eavesdroppers in multi-input multi-output (MIMO) systems and/or relay systems. However, there are still a large number of nodes which do not have multi-antennas or support sophisticated protocols in wireless networks. In this paper, a novel AN-aided method is proposed to secure wireless communications between the legitimate users (not equipped with multiple antennas) in the presence of an eavesdropper. In this proposed method frequency selective property of wireless channel is exploited. The basic principle is same in which transmitter generate random AN signal utilizing some of the transmission power to confuse eavesdropper. However artificial noise is generated in such a way that it appears to be zero at the sampling time, only for the legitimate receiver while degrading eavesdropper's channel. Artificial noise is specified using the channel state information (CSI) of the legitimate users' link. However, the secrecy of proposed scheme doesn't depend on the secrecy of CSI. Extensive simulation suggests that the proposed scheme can effectively utilized for securing wireless transmissions.\",\n \"Title: Spatial Modulation Aided Physical Layer Security Enhancement For Fading Wiretap Channels\\nYear: 2016\\n\\nAbstract: In this paper, the spatial modulation (SM) technique is explored to improve physical layer security in time-division duplex (TDD) wireless communication network. In the designed transmission scheme, the transmitter first exploits the knowledge of legitimate channel state information (CSI) to redefine the transmit antennas' indices which are used to map into spatial bits, then selects one activated antenna based on the renaming rule to transmit the modulation symbol. The communications security can be improved because the eavesdropper cannot detect the spatial bits information without the perfect legal CSI. Our studies derive the secrecy mutual information of the presented method. The numerical results on secrecy mutual information and bit error rate (BER) demonstrate the effectiveness and robustness of the proposed secrecy communications scheme.\",\n \"Title: Secure Communication Using Noisy Feedback.\\nYear: 2016\\n\\nAbstract: In this paper, the critical effect of noisy feedback in improving the physical layer security is investigated. Unlike previous works, where the eavesdropper's channel state information (either the instantaneous channel state information or the channel distribution information) is assumed known, a feedback and jamming scheme without any eavesdropper's channel state information is studied, which allows both the source and legal destination to transmit private message and degrade the eavesdropper alternatively in different phase of the transmission. More specifically, the situation in which no power constraint is considered first, and it shows using channel inversion a positive secrecy rate can always be achieved by mixing proper amount of artificial noise in the private signal, and the secrecy rate grows linearly with the power of private message in dB. Then we consider the practical situation with power constraint. Interestingly, it shows that a positive secrecy rate can also be obtained by using truncated channel inversion and selecting proper cutoff value and jamming power. Finally, the numerical results verify our analysis.\",\n \"Title: Cooperative Physical-Layer Approach for Downlink Privacy Preserving in Multiuser Relay Networks.\\nYear: 2016\\n\\nAbstract: This paper studies privacy-preserving for downlink transmission in multiuser relay systems, where a source communicates with multiple users via a relay employing the amplifyand- forward (AF) protocol. At any scheduling unit, only one user (desired user) is selected to receive the source information, and the other users (undesired users) are viewed as potential eavesdroppers due to the broadcast nature of wireless medium. A cooperative physical-layer scheme is proposed to prevent information leakage. The key idea of this scheme is to schedule a cooperating user in addition to the desired user to deliver the artificial noise (AN). By exploiting the characteristics of channels, the cooperating user carefully designs the AN transmitted during two time slots such that the AN can be cancelled out at the desired user, but can not be removed at the undesired users. As a result, the detection performance of the desired user is free of interference, while that of undesired users is heavily degraded, thereby preserving the data confidentiality of the desired user. To maximize the secrecy rate of the system, a user scheduling policy is developed. Further, the lower bound of the ergodic secrecy rate (ESR) is derived, and its asymptotic behavior is analyzed via extreme value theory (EVT). Theoretical analysis and simulation results show that, thanks to the proposed cooperative AN injection mechanism, the system ESR grows with the increasing number of users, and much higher secrecy rate can be achieved compared to the existing schemes in literature.\",\n \"Title: Optimal power allocation for cognitive radio sensor networks under primary secrecy outage constraint\\nYear: 2016\\n\\nAbstract: To secure the primary network, in this paper, we propose a cooperative spectrum access strategy in which the cognitive radio sensor network (CRSN) will cooperate with the primary network to protect the primary confidential messages against malicious eavesdropping and the quality of service (QoS) is supported. In the proposed scheme, the CRSN will exploit its interference on the eavesdropper to secure the primary transmission and as a reward, loose constraint of the spectrum sensing error probability is permitted for the CRSN. According the spectrum sensing results and the activities of primary network, there are four system states in the system. For each state, we will optimally allocate the transmit power of the CRSN so that the average transmission rate of the CRSN is maximized under the secrecy outage probability constraint of the primary network. Moreover, the closed-form expression of the transmit power for each state is derived. Simulation results demonstrate the performance superiority of our proposed strategy over the conventional overlay strategy in terms of SN's average throughput.\",\n \"Title: A Hybrid Channel Estimation Strategy Against Pilot Spoofing Attack In Miso System\\nYear: 2016\\n\\nAbstract: Pilot spoofing attack can deteriorate the transmission performance of the legitimate system and facilitate eavesdropping concurrently. Some detection methods of pilot attack have been proposed, while we consider the problem of channel estimation under pilot spoofing attack. In this paper, a hybrid channel estimation strategy using random Binary Phase Shift Keying (BPSK) is proposed. Specifically, a random BPSK sequence is transmitted by the legal user once the attack is detected. In this manner, the base station detects the sequence and re-estimates the legal channel with both contaminated pilot and assistant sequence. We evaluate the estimation performance in three cases according to different responses of the malicious user. Simulation results demonstrate that the proposed strategy can effectively estimate the legitimate channel against pilot attack.\",\n \"Title: Deep LSTM Networks for Online Chinese Handwriting Recognition\\nYear: 2016\\n\\nAbstract: Currently two heavy burdens are borne in online Chinese handwriting recognition: a large-scale training data needs to be annotated with the boundaries of each character and effective features should be handcrafted by domain experts. To relieve such issues, the paper presents a novel end-to-end recognition method based on recurrent neural networks. A mixture architecture of deep bidirectional Long Short-Term Memory (LSTM) layers and feed forward subsampling layers is used to encode the long contextual history trajectories. The Connectionist Temporal Classification (CTC) objective function makes it possible to train the model without providing alignment information between input trajectories and output strings. During decoding, a modified CTC beam search algorithm is devised to integrate the linguistic constraints wisely. Our method is evaluated both on test set and competition set of CASIA-OLHWDB 2. x. Comparing with state-of-the-art methods, over 30% relative error reductions are observed on test set in terms of both correct rate and accurate rate. Even to the more challenging competition set, better results can be achieved by our method if the out-of-vocabulary problem can be ignored.\",\n \"Title: Noncontact Physiological Dynamics Detection Using Low-power Digital-IF Doppler Radar.\\nYear: 2017\\n\\nAbstract: The instantaneous vital sign rates, which are related to physiological dynamics, are important indicators of human health condition. This paper presents a noncontact way to measure the human instantaneous vital signs using digital-intermediate frequency (IF) Doppler radar. The synchrosqueezing transform-based algorithm has been proposed to get a concentrated time-frequency (TF) distribution, so th...\",\n \"Title: Secure Cooperative Transmission Against Jamming-Aided Eavesdropper for ARQ Based Wireless Networks.\\nYear: 2017\\n\\nAbstract: Secure the cooperative transmission is studied for an automatic repeat request (ARQ)-based wireless network against a jamming-aided eavesdropper. The eavesdropper utilizes the jamming attack to assist its eavesdropping by forcing the legitimate transmitter to retransmit its confidential messages under poor wiretap channel quality. Then, utilizing these retransmission opportunities, the eavesdropper will eavesdrop the confidential message under good wiretap channel quality. To address the threat from the jammingaided eavesdropper in the ARQ-based wireless network, we propose an adaptive cooperative relaying and jamming secure transmission scheme to protect the confidential messages. In the proposed scheme, the legitimate receiver adopts the energy detection method to detect the jamming-aided eavesdropper's action and a cooperative node will aid the secure transmission through cooperative relaying under jamming attack or cooperative jamming under eavesdropping attack. By taking into account of the detection errors, we investigate the transmission outage probability and the secrecy outage probability, and derive their closed-form expressions for both one retransmission and multiple retransmissions scenarios. Numerical results are presented to verify the derived analytical results and demonstrate the performance superiority of the proposed scheme in terms of the secrecy outage probability.\",\n \"Title: A fully end-to-end deep learning approach for real-time simultaneous 3D reconstruction and material recognition\\nYear: 2017\\n\\nAbstract: This paper addresses the problem of simultaneous 3D reconstruction and material recognition and segmentation. Enabling robots to recognise different materials (concrete, metal etc.) in a scene is important for many tasks, e.g. robotic interventions in nuclear decommissioning. Previous work on 3D semantic reconstruction has predominantly focused on recognition of everyday domestic objects (tables, chairs etc.), whereas previous work on material recognition has largely been confined to single 2D images without any 3D reconstruction. Meanwhile, most 3D semantic reconstruction methods rely on computationally expensive post-processing, using Fully-Connected Conditional Random Fields (CRFs), to achieve consistent segmentations. In contrast, we propose a deep learning method which performs 3D reconstruction while simultaneously recognising different types of materials and labeling them at the pixel level. Unlike previous methods, we propose a fully end-to-end approach, which does not require hand-crafted features or CRF post-processing. Instead, we use only learned features, and the CRF segmentation constraints are incorporated inside the fully end-to-end learned system. We present the results of experiments, in which we trained our system to perform real-time 3D semantic reconstruction for 23 different materials in a real-world application. The run-time performance of the system can be boosted to around 10Hz, using a conventional GPU, which is enough to achieve realtime semantic reconstruction using a 30fps RGB-D camera. To the best of our knowledge, this work is the first real-time end-to-end system for simultaneous 3D reconstruction and material recognition.\",\n \"Title: Weakly-supervised DCNN for RGB-D Object Recognition in Real-World Applications Which Lack Large-scale Annotated Training Data.\\nYear: 2017\\n\\nAbstract: This paper addresses the problem of RGBD object recognition in real-world applications, where large amounts of annotated training data are typically unavailable. To overcome this problem, we propose a novel, weakly-supervised learning architecture (DCNN-GPC) which combines parametric models (a pair of Deep Convolutional Neural Networks (DCNN) for RGB and D modalities) with non-parametric models (Gaussian Process Classification). Our system is initially trained using a small amount of labeled data, and then automatically prop- agates labels to large-scale unlabeled data. We first run 3D- based objectness detection on RGBD videos to acquire many unlabeled object proposals, and then employ DCNN-GPC to label them. As a result, our multi-modal DCNN can be trained end-to-end using only a small amount of human annotation. Finally, our 3D-based objectness detection and multi-modal DCNN are integrated into a real-time detection and recognition pipeline. In our approach, bounding-box annotations are not required and boundary-aware detection is achieved. We also propose a novel way to pretrain a DCNN for the depth modality, by training on virtual depth images projected from CAD models. We pretrain our multi-modal DCNN on public 3D datasets, achieving performance comparable to state-of-the-art methods on Washington RGBS Dataset. We then finetune the network by further training on a small amount of annotated data from our novel dataset of industrial objects (nuclear waste simulants). Our weakly supervised approach has demonstrated to be highly effective in solving a novel RGBD object recognition application which lacks of human annotations.\",\n \"Title: Anti-Eavesdropping Scheme Based on Quadrature Spatial Modulation.\\nYear: 2017\\n\\nAbstract: To resist the passive eavesdropping while reserving the same hardware cost and receiver structure of the legitimate receiver, a secure quadrature spatial modulation (QSM) scheme is proposed in this letter. Instead of the information symbol, a mixture of the information symbol and artificial noise is transmitted through the activated transmit antennas. The mixed signals are designed, so that the artificial noise is cancelled at the legitimate receiver but cause random interference to the eavesdropper. The secrecy rate is analyzed and the optimal power allocation between the artificial noise and the information signal is investigated. The influence of the number of the eavesdropper's antennas is discussed. Simulation results show that, for multiple-input-single-output systems, the proposed secure QSM scheme achieves the best secrecy performance among the existing similar schemes by using less radio frequency chains. For multiple-input-multiple-output systems, the secure QSM scheme performs better than the existing secure SM scheme does under the same power constraint and transmission rate.\",\n \"Title: Modified multiple measurement vectors model for squinted synthetic aperture radar imaging.\\nYear: 2017\\n\\nAbstract: Inspired by the theoretical advances of compressed sensing, lots of sparsity-aware methods have been proposed for squinted synthetic aperture radar (SAR) imaging based on the single-measurement vector (SMV) model. Compared with SMV, the multiple measurement vectors (MMV) model has been demonstrated to have better reconstruction performance. In fact, echo received by SAR at different azimuth positions can be viewed as MMVs. However, the MMV model cannot be directly used in squinted SAR imaging, because MMV requires multiple sparse vectors of the common sparse structures, while the high-resolution range profiles (HRRPs) obtained by squinted SAR at different azimuth positions have different sparse structures due to range migration effect. A squinted SAR imaging method is proposed based on MMV. First, a modified MMV model that considers range migration is built to realize sparse representation of echo. Additionally, an improved orthogonal matching pursuit algorithm is developed to reconstruct HRRPs. Finally, a high-resolution two-dimensional image result can be easily achieved via traditional azimuth match filtering. Experimental results based on both simulated and real data demonstrate that the proposed MMV-based method can provide better computational efficiency and antinoise ability compared to the SMV-based method. (C) 2017 SPIE and IS&T\",\n \"Title: Enhancing physical-layer security via big-data-aided hybrid relay selection.\\nYear: 2017\\n\\nAbstract: The explosive growth in data traffic presents new challenges to the new generation of wireless communication systems, such as computing capabilities, spectrum efficiency and security. In this paper, we use the network structure, which is adaptable for the big data traffic, to improve the security of wireless networks. Specifically, a big-data aided hybrid relay selection scheme is designed and analyzed to enhance physical layer security. First, considering the ideal situation that an eavesdropper’s CSI (Channel State Information) is known to the legal nodes, we propose an optimal hybrid relay selection scheme consisting of the optimal mode selection scheme and the optimal relay selection scheme. In this case, we analyze the upper bound of an eavesdropper’s capacity in FD (Full-Duplex) mode and the secrecy outage probabilities of the optimal HD (Half-Duplex), FD, and hybrid relay selection schemes. Through the analysis of data, it is clear that the mode selection is decided by the self-interference of the FD technique. However, the instantaneous CSI of an eavesdropper is difficult to obtain due to the passive characteristic of eavesdroppers in practice. Therefore, a more practical hybrid relay selection scheme with only the channel distribution information of an eavesdropper is further studied, where a weighting factor is employed to guarantee that the hybrid mode is no worse than either the FD mode or HD mode when the self-interference grows. Finally, the simulation results show the improved security of our proposed scheme.\",\n \"Title: Robust Relay in Narrow-Band Communications for Ubiquitous IoT Access.\\nYear: 2017\\n\\nAbstract: We propose a robustwireless relay scheme in narrow-band communications for IoT access, whichmatches the typical features of IoT often carrying relatively low data rate with limited bandwidth. This framework is towards offering robustness in QoS guarantees with emphases on security and/or reliability, and we use the security-assured network as the typical scenario. In particular, we consider a dual-hop relay network including a transmitter, a receiver, an amplify-and-forward (AF) untrusted relay, and a jamming node. The jamming node is treated as a helper. Specifically, the jammer broadcasts artificial noise (AN), which in fact pollutes both the untrusted relay and the destination node's signals. However, we show that such AN can be effectively mitigated after the destination node obtains the forwarded signal from the relay, while the untrusted relay node cannot do so. The core idea for robustness assurance is to exploit higher signal dimensions at the receiver over the untrusted relay node. Simulations and analyses are also conducted to demonstrate that our proposed scheme can make the performance at the untrusted relay an interferencelimited manner while completely removing the interferences at the receiver, therefore corroborating our claim in robustness in terms of security and reliability.\",\n \"Title: Robust, Efficient Depth Reconstruction With Hierarchical Confidence-Based Matching.\\nYear: 2017\\n\\nAbstract: In recent years, taking photos and capturing videos with mobile devices have become increasingly popular. Emerging applications based on the depth reconstruction technique have been developed, such as Google lens blur. However, depth reconstruction is difficult due to occlusions, non-diffuse surfaces, repetitive patterns, and textureless surfaces, and it has become more difficult due to the unstable image quality and uncontrolled scene condition in the mobile setting. In this paper, we present a novel hierarchical framework with multi-view confidence-based matching for robust, efficient depth reconstruction in uncontrolled scenes. Particularly, the proposed framework combines local cost aggregation with global cost optimization in a complementary manner that increases efficiency and accuracy. A depth map is efficiently obtained in a coarse-to-fine manner by using an image pyramid. Moreover, confidence maps are computed to robustly fuse multi-view matching cues, and to constrain the stereo matching on a finer scale. The proposed framework has been evaluated with challenging indoor and outdoor scenes, and has achieved robust and efficient depth reconstruction.\",\n \"Title: Primary Secure Communication With The Cooperation Of Energy Harvesting Secondary System\\nYear: 2016\\n\\nAbstract: Aiming at providing secure provisioning for the primary system, in this paper, we propose an energy harvesting based cooperative communication (EHCC) scheme which will protect the primary confidential message from eavesdropping under the constraint of the secondary quality-of-service (QoS) requirement. To do so, the secondary receiver (SR) firstly transmits jamming signal to protect the primary transmission and then, the secondary transmit (ST) harvests part of the received signals and forwards the remaining signals to the primary receiver (PR) concurrently with the secondary transmission. In our proposed scheme, radio-frequency energy harvesting will improve ST's maximum transmit power and the jamming interference at SR can be directly cancelled as SR has transmitted it. Then, we try to allocate the transmit power and design energy harvesting parameters in such a way that the secrecy capacity of the primary system is maximized under the constraint of the secondary QoS requirement. In addition, an iterative algorithm is proposed to solve this non-convex problem. Moreover, we also analyze the primary secrecy capacities and allocate the resource for the asymptotic scenarios. Simulation results demonstrate the performance superiority of our proposed scheme over the conventional cooperative secure communication scheme in terms of the primary secrecy capacity.\",\n \"Title: Secure And Energy Efficient Transmission In Multiuser Uplink Wireless Networks\\nYear: 2016\\n\\nAbstract: Security and energy efficiency are two critical metrics in many multiuser networks (e.g. M2M networks, sensor networks and ad hoc networks). In this paper, we try to maximize secure energy efficiency (SEE) by allocating power for those User Equipments (UEs) meeting the security transmission requirements, where SEE is defined as the ratio of the total secrecy throughput to the total transmission power in the whole network. Concretely, we propose an efficient algorithm which uses the parametric programming and Difference of Convex (DC) function to solve the optimization problem (i.e. maximize secure energy efficiency). Finally, we compare the secure energy efficiency of our scheme with that of fixed power allocation schemes and show the results through simulations at different system conditions.\",\n \"Title: Two-path successive relaying and jamming for securing the primary system\\nYear: 2016\\n\\nAbstract: To guarantee secure communication of the primary system and efficiently utilize the licensed spectrum, in this paper, we propose a two-path successive relaying and jamming based cooperative transmission (TSRJC) scheme. In TSRJC scheme, two secondary users (SU) successively relay the primary message and jam the primary eavesdropper to confirm secure and reliable transmission of the primary system during the first stage. During the second stage, the secondary system will be allowed to access the licensed spectrum for the secondary transmission as a reward. To maximize the secondary transmission, a suboptimal algorithm is proposed to allocate the relaying and jamming power. In addition, the closed-form expressions of both SU's relaying and jamming power and jamming power beamforming vector are derived. Simulation results demonstrate the superior performance of our developed scheme over conventional secure communication scheme in terms of primary users' (PU) secure outage probability and SUs' average transmission rate.\",\n \"Title: Multi-resolution-based road state estimation\\nYear: 2016\\n\\nAbstract: In this paper, we suggest an accessible and effective approach to the urban road state estimation. The main technical contribution of the proposed method is a novel feature extraction on the basis of the multi-resolution, along with support vector machine for classification. Experimental tests have been carried out to validate our proposed approach which can estimate road state in the sample of a hundred of city road images computational efficiently and effectively.\",\n \"Title: One sample based feature learning for vehicle identification\\nYear: 2016\\n\\nAbstract: Vehicle identification is one of the frequently studied problems in video surveillance. Commonly, identifying an unknown vehicle object requires a large amount of training instances. Unfortunately, in the large parking scenario, the cost may be prohibitively expensive because of the finitely waiting time from the car owners. In this paper, we show that it is possible to identify a registered vehicle using a single training example. The key insight is that, the human visually representative properties, such as overall appearance and local texture, are described using colors and histogram of oriented gradient (HOG). They are firstly extracted from each patch to form the fundamental representation. After that, the well developed locality-constrained linear coding (LLC) technique is employed to learn a more informative representation. Next, with nearest neighbors (NN) servers as the main classifier, the classical genetic algorithm (GA) is utilized to decide the most informative patches so that the minimum mis-identified error is achieved. The proposed approach is experimentally demonstrated and evaluated on the open “Dana36” data set using vehicle images that are taken under an approximate camera pose. Good improvements are obtained with respect to the strategies that do not use LLC encoded features and selectively combined patches.\",\n \"Title: Image segmentation based on 2D OTSU and simplified swarm optimization\\nYear: 2016\\n\\nAbstract: Image segmentation is a classic problem and basic research area in image processing. It can provide pre-detect information for subsequent image processing and classification. 2D Otsu method is a widely used non-parametric method to detect the threshold of image. In this paper, we employ the simplified swarm optimization (SSO) as a swarm-intelligent optimization method to search the threshold value based on 2D Otsu method. Experimental result has shown that the proposed method could consume less computation time of 2D Otsu method and achieve the optimal value.\",\n \"Title: ESPS scheme for two-tier interference suppression in a heterogeneous network with cooperative femtocells\\nYear: 2015\\n\\nAbstract: The coexistence of a macrocell and a number of femtocells often leads to a two‐tier\\n heterogeneous network, where the co‐tier interference (CotIN) and cross‐tier interference\\n (CrotIN) both degrade users' quality of service. In order to suppress these interferences,\\n we propose a precoding scheme in a heterogeneous network with cooperative femtocells,\\n called CotIN elimination and CrotIN suppression with precoding criterion selection\\n (ESPS) scheme. In this scheme, we first eliminate the CotINs of each user by applying\\n the QR decomposition to channel matrix. Then the CrotINs of macrocell users and femtocell\\n users are suppressed via the macrocell base station (MBS) and femtocell access points\\n (FAPs) with precoding criterion selection, respectively. By using the ESPS scheme,\\n spatial resources can be efficiently exploited. In addition, our ESPS scheme requires\\n little information exchange between MBS and FAPs without iteration and thus significantly\\n reduces the implementation complexity. Furthermore, the robustness is increased through\\n introducing the information of channel uncertainty into the ESPS when channel estimation\\n or quantization error exists. The performance analysis for the ESPS demonstrates that\\n the ESPS is practical in the heterogeneous networks. Finally, simulation results show\\n that the ESPS can decrease users' bit error rates and increase their transmission\\n rates. Copyright © 2015 John Wiley & Sons, Ltd.\",\n \"Title: Efficient incremental dynamic link prediction algorithms in social network.\\nYear: 2017\\n\\nAbstract: To enhance customers’ loyalty and experience, link prediction in social networks can help service providers to predict the friendship between users in the future, according to the network structure and personal information. However, most of prior studies consider link prediction in the static scenario while ignoring that the social network generally is updated over time. In this paper, to address this problem, we design two efficient incremental dynamic algorithms that can predict the relationship between users according to the updated social network structure. The first one, instead of using classic prediction index, creates a latent space for each node in the network, and adopts the incremental calculation to predict the future links according to the position of each node in the latent space. The second one is a dynamic improved algorithm based on the resource allocation index, which only recalculates updated part of the social network structure instead of the whole social network. Extensive experiments show that our first algorithm has high prediction accuracy while the second algorithm incurs low running time cost at the expense of less prediction accuracy.\",\n \"Title: Exploring the Difficulties African-American Middle School Girls Face Enacting Computational Algorithmic Thinking over three Years while Designing Games for Social Change.\\nYear: 2017\\n\\nAbstract: Computational algorithmic thinking (CAT) is the ability to design, implement, and assess the implementation of algorithms to solve a range of problems. It involves identifying and understanding a problem, articulating an algorithm or set of algorithms in the form of a solution to the problem, implementing that solution in such a way that the solution solves the problem, and evaluating the solution based on some set of criteria. CAT is an important scaffolded on-ramp as students develop more advanced computational thinking capabilities and apply computational thinking to solve problems that are more constrained and require greater expertise. Supporting Computational Algorithmic Thinking (SCAT) is both a longitudinal between-subjects research project and a free enrichment program supporting and guiding African-American middle school girls over three years as they iteratively design a set of complex games for social change. This article explores Scholars' reflections about the difficulties they faced while using CAT capabilities as they engaged in collaborative game design for social change over those three years. We particularly focus on how these difficulties changed over the course of three years as well as new difficulties that emerged from year to year as Scholars become more expert game designers and computational algorithmic thinkers.\",\n \"Title: Interference-constrained routing over P2P-share enabled multi-hop D2D networks.\\nYear: 2017\\n\\nAbstract: The exponentially-increasing demands on ubiquitous information exchange have inspired wide research interests and efforts on the 5th Generation (5G) of mobile communications system. Among diverse cutting-edge revolutionary technologies towards 5G networks, device-to-device (D2D) networks, where device nodes can communicate with each other by reusing the cellular network’s spectrum in an underlay fashion. We in this paper propose the interference-constrained routing schemes over peer-to-peer (P2P) share enabled multi-hop D2D networks, where multiple D2D subscribers attempt to download the common data from multiple distributed D2D servers. In particular, we aim at optimizing the average download rate over subscribers subject to the interference constraint for cellular network’s spectrum. We first focus on a typical case with two subscribers, two file servers, and two cellular users. We propose a Routing scheme with Direct P2P-Share (R-DPS), which allows subscribers to distribute their received data to each other via a detoured route. To offer better performances, we develop an improved Routing scheme, named Coverage-based P2P-Share (R-CPS). The R-CPS scheme can effectively make use of the broadcast nature of wireless channels to assure that each selected route can cover the other subscriber, rather than directly pass through them in the R-DPS scheme. We further study the generalized case where the number of subscribers, servers, and cellular users can be arbitrary. Particularly, we propose a Routing scheme with Location-Aware P2P-Share (R-LPS) mechanism, the core idea of which is to find a route passing by or directly through other subscribers. Simulation evaluations demonstrate that our proposed R-DPS and R-CPS schemes for the two-subscriber case and the R-LPS scheme for the generalized case all have the capability to effectively improve the data download rate as compared to the approach without enabling P2P support.\",\n \"Title: Ica-Sbdc: A Channel Estimation And Identification Mechanism For Miso-Ofdm Systems Under Pilot Spoofing Attack\\nYear: 2017\\n\\nAbstract: Pilot spoofing attack is a serious threat to time-division duplex (TDD) orthogonal frequency division multiplexing (TDD-OFDM) system. By employing identical pilot tones as a legitimate receiver, an adversary can contaminate the uplink channel estimation between a transceiver pair. To solve this problem, we in this paper propose an independent component analysis (ICA) based channel estimation and identification mechanism with a subcarrier-block discriminating coding (SBDC) technique (ICA-SBDC). Firstly, a receiver randomizes the values of its pilot tones to avoid contamination, which however incurs pilot jamming attack. A minor-component-based detector (MCD) is devised to detect the attack efficiently. Secondly, the transmitter exploits the fourth-order statistical information of received signals to extract a linear-mixing channel. We can prove that given previously used legitimate pilots, both legitimate and attack sub-channels can be recovered from the obtained channel. Finally, the receiver maps its utilized pilots into various uplink transmission strategies on subcarrier-blocks which can be ultimately identified by the transmitter in a jamming environment. The mapping therein is formulated via a public-known codebook with discriminating algebraic property and the identification is achieved by decoding the codebook according to the results of MCD-based detection for each subcarrier-block. Simulation results verify the effectiveness of our proposed mechanism.\",\n \"Title: Combat Eavesdropping By Full-Duplex Technology And Signal Transformation In Non-Orthogonal Multiple Access Transmission\\nYear: 2017\\n\\nAbstract: Non-orthogonal multiple access (NOMA) is an important multiple access mode in 5G. Nevertheless, eavesdropping may appear between the users in NOMA. In this case, physical layer security schemes can be introduced to combat eavesdropping. Different from the existing schemes, eavesdropping suppression in NOMA should be based on several rules: (i) successive interference cancellation (SIC) should be normally operated; (ii) each user can not attain others' privacy information; (iii) each adopted scheme had better not to depend on the spatial disparity between channels (since the channels may have the strong spatial similarity). Therefore, we propose a novel scheme to adapt to these rules. In our scheme, the original signals of users are separately transformed into the transmitted signals by a well-designed angle conversion method, and the principles of these variations for diverse users are different. Furthermore, an auxiliary mechanism with full-duplex technology is devised to guarantee the users to safely learn the principles, respectively. Through this scheme, each user can deduce other users' transmitted signals for SIC, while the original signals are difficult to be determined from transmitted signals. Hence, our scheme can effectively improve security.\",\n \"Title: Age Estimation by Refining Label Distribution in Deep CNN.\\nYear: 2017\\n\\nAbstract: This paper proposes an age estimation algorithm by refining the label distribution in a deep learning framework. There are two tasks during the training period of our algorithm. The first one finds the optimal parameters of supervised deep CNN by given the label distribution of the training sample as the ground truth, while the second one estimates the variances of label distribution to fit the output of the CNN. These two tasks are performed alternatively and both of them are treated as the supervised learning tasks. The AlexNet and ResNet-50 architectures are adopted as the classifiers and the Gaussian form of the label distribution is assumed. Experiments show that the accuracy of age estimation can be improved by refining label distribution.\",\n \"Title: Passenger Travel Path Estimation Algorithm Based on High Accuracy Location Data\\nYear: 2017\\n\\nAbstract: With the rapid development of rail transit, urban rail transit network is increasingly becoming complex due to the intersection of the different operating lines. In order to guarantee the convenience of passenger's travel, most domestic the existing metro system passengers' records are only retrieved at entry and exit points. With such a system, it is difficult to track the passengers' complete path since they usually go through different lines before arriving their final destinations, so it is difficult for the different subway operators to fare clearing. To determine the complete travel path of passengers in a metro system, path estimation methods based on shortest path algorithm, Logit technique, and the normal function model have been proposed. These methods basically depend on passenger surveys, low data samples, and long adjustment periods for model parameters which limit their accuracy in practical application. Therefore, in order to get the complete path of passengers for support subway operators to fare clearing, this paper presents a novel passenger travel path estimation algorithm based on indoor high precision positioning data, combined with high-precision indoor positioning technology. And revert the passenger's track of each site, through the whole network of more than 60% of the user's actual travel trajectory to obtain the passenger's selection probability of travel path. And this suggests that the proposed model may provide data support for urban rail transit passenger clearance in the metro system.\",\n \"Title: Improved Uneven Cluster-Based routing protocol based on CRT algorithm.\\nYear: 2017\\n\\nAbstract: Energy-Efficient Uneven Clustering (EEUC) protocol is applied to low-redundancy Wireless Sensor Network (WSN), the uneven consumption of sensor node energy leads to nodes' early death which will seriously affect the network quality. This paper proposes the Chinese Remainder Theorem (CRT) division algorithm for EEUC Energy-Efficient Uneven Clustering routing protocol optimization. The nodes split the packets before forwarding and balance the energy consumption of the nodes forward packets which results in alleviating hot problems of wireless sensor networks. We also add energy and distance parameters to the threshold function in the cluster heads selection mechanism, and optimize the cluster semidiameter to make the cluster head election distribution more reasonable which will help to optimize the network energy consumption. The result of simulation indicates that the algorithm we propose can make energy consumption of lower redundant sensor network nodes more balanced and delay the first death time of node as well as prolong the network life time effectively.\",\n \"Title: Localization Research about the Node without Identifies for the Sparse WSN Environment.\\nYear: 2017\\n\\nAbstract: For the problem of nodes without identifies and quantity in the environment of wireless sensor network, a new route model of mobile anchor node is provided. The model composed of the one heavy path and the three heavy path. The paper first is to obtain the optimal path through traversing all of the fixed virtual anchor nodes using the model of TSP, and then enters the three heavy path while anchor node sense the unknown nodes in the one heavy path. After have received the three numbers of RSSI data, the anchor node returned to one heavy path. Finally, the location and numbers of the unknown nodes will be obtained after generalize all of the nodes using iterative methods. The experimental results show that, in the case of the unknown nodes distributed sparse, the proposed path model can reduce the redundant path and the moving time, which reached the goal of the high precision of location.\",\n \"Title: Rural Building Detection in High-Resolution Imagery Based on a Two-Stage CNN Model.\\nYear: 2017\\n\\nAbstract: High-level feature extraction and hierarchical feature representation of image objects with a convolutional neural network (CNN) can overcome the limitations of the traditional building detection models using middle/low-level features extracted from a complex background. Aiming at the drawbacks of manual village location, high cost, and the limited accuracy of building detection in the existing ru...\",\n \"Title: Development and Evaluation of A Novel and Cost-Effective Approach for Low-Cost NO2 Sensor Drift Correction.\\nYear: 2017\\n\\nAbstract: Emerging low-cost gas sensor technologies have received increasing attention in recent years for air quality measurements due to their small size and convenient deployment. However, in the diverse applications these sensors face many technological challenges, including sensor drift over long-term deployment that cannot be easily addressed using mathematical correction algorithms or machine learning methods. This study aims to develop a novel approach to auto-correct the drift of commonly used electrochemical nitrogen dioxide (NO2) sensor with comprehensive evaluation of its application. The impact of environmental factors on the NO2 electrochemical sensor in low-ppb concentration level measurement was evaluated in laboratory and the temperature and relative humidity correction algorithm was evaluated. An automated zeroing protocol was developed and assessed using a chemical absorbent to remove NO2 as a means to perform zero correction in varying ambient conditions. The sensor system was operated in three different environments in which data were compared to a reference NO2 analyzer. The results showed that the zero-calibration protocol effectively corrected the observed drift of the sensor output. This technique offers the ability to enhance the performance of low-cost sensor based systems and these findings suggest extension of the approach to improve data quality from sensors measuring other gaseous pollutants in urban air.\",\n \"Title: Dense RGB-D semantic mapping with Pixel-Voxel neural network.\\nYear: 2018\\n\\nAbstract: In this paper, a novel Pixel-Voxel network is proposed for dense 3D semantic mapping, which can perform dense 3D mapping while simultaneously recognizing and labelling the semantic category each point in the 3D map. In our approach, we fully leverage the advantages of different modalities. That is, the PixelNet can learn the high-level contextual information from 2D RGB images, and the VoxelNet can learn 3D geometrical shapes from the 3D point cloud. Unlike the existing architecture that fuses score maps from different modalities with equal weights, we propose a softmax weighted fusion stack that adaptively learns the varying contributions of PixelNet and VoxelNet and fuses the score maps according to their respective confidence levels. Our approach achieved competitive results on both the SUN RGB-D and NYU V2 benchmarks, while the runtime of the proposed system is boosted to around 13 Hz, enabling near-real-time performance using an i7 eight-cores PC with a single Titan X GPU.\",\n \"Title: Security Provisioning for MISO Vehicular Relay Networks via Cooperative Jamming and Signal Superposition.\\nYear: 2017\\n\\nAbstract: We study the cooperative secure transmissions in (multiple-input signal-output) MISO vehicular relay networks where the infrastructure node with multiple antennas sends two confidential messages to two legitimate vehicles with only one antenna, respectively. By exploiting the signal superposition and cooperative jamming techniques, the legitimate vehicle near the infrastructure node directly decod...\",\n \"Title: Design for NOMA: Combat Eavesdropping and Improve Spectral Efficiency in the Two-User Relay Network.\\nYear: 2017\\n\\nAbstract: Non-orthogonal multiple access (NOMA) is important in 5G, and the users served in NOMA are often paired to avoid the excessive interference. However, for a two-user network, if the channel condition of one user is serious, this network may require the other user to relay this user's signals. In this case, the demands of these users are possibly different. Specifically, the relay user may want the node to increase the spectral efficiency for compensating the cost of relay. On the other hand, because privacy information may be contained in signals, the indirect communication user may primarily focus on his or her information security. Therefore, we propose a novel physical layer scheme to satisfy these demands. Different from the existing relay schemes in NOMA, our scheme has the following characteristics: (i) through power allocation, the relay user can extract his or her signals with spectral efficiency improvement; (ii) through a signal-level method, the relay user can forward the indirect communication user's signals, but he or she is difficult to learn the privacy information in these signals; (iii) through a mechanism, the indirect communication user can attain his or her privacy information. Our scheme is able to support the relay user's demand, and this eavesdropping suppression in our scheme doe not depend on the complicated encryption techniques and positive secrecy rate.\",\n \"Title: An Artificial Noise-Based Security Scheme for Interference Alignment-Based Wireless Networks.\\nYear: 2017\\n\\nAbstract: The security of the interference alignment (IA)based networks is of uttermost importance for the application of interference alignment in multi-user networks. Several recent works have utilize the physical layer security schemes including artificial noise (AN) and friendly jamming etc. to reduce the eavesdropping capabilities of an outside eavesdropper. In this paper, we propose a novel AN-based anti-eavesdropping scheme in IA-based networks where the AN and the interferences are aligned into two different subspaces at the desired receiver. This results in more confusion to the eavesdropper and an enhancement of the desired signal simultaneously. The simulations testify this observation.\",\n \"Title: Person Re-id by Incorporating PCA Loss in CNN.\\nYear: 2018\\n\\nAbstract: This paper proposes an algorithm, particularly a loss function and its end to end learning manner, for person re-identification task. The main idea is to take full advantage of the labels in a batch during training, and to employ PCA to extract discriminative features. Deriving from the classic eigenvalue computation problem in PCA, our method incorporates an extra term in loss function with the purpose of minimizing those relative large eigenvalues. And the derivative with respect to the designed loss can be back-propagated in deep network by stochastic gradient descent (SGD). Experiments show the effectiveness of our algorithm on several re-id datasets.\",\n \"Title: Multisensor Online Transfer Learning for 3D LiDAR-based Human Classification with a Mobile Robot.\\nYear: 2018\\n\\nAbstract: Human detection and tracking is an essential task for service robots, where the combined use of multiple sensors has potential advantages that are yet to be fully exploited. In this paper, we introduce a framework allowing a robot to learn a new 3D LiDAR-based human classifier from other sensors over time, taking advantage of a multisensor tracking system. The main innovation is the use of different detectors for existing sensors (i.e. RGB-D camera, 2D LiDAR) to train, online, a new 3D LiDAR-based human classifier based on a new “trajectory probability”. Our framework uses this probability to check whether new detection belongs to a human trajectory, estimated by different sensors and/or detectors, and to learn a human classifier in a semi-supervised fashion. The framework has been implemented and tested on a real-world dataset collected by a mobile robot. We present experiments illustrating that our system is able to effectively learn from different sensors and from the environment, and that the performance of the 3D LiDAR-based human classification improves with the number of sensors/detectors used.\",\n \"Title: Towards win-win: weighted-Voronoi-diagram based channel quantization for security enhancement in downlink cloud-RAN with limited CSI feedback.\\nYear: 2017\\n\\nAbstract: Physical layer (PHY) security is recently proved to enable improving the security of wireless communication networks. In downlink frequency division duplex (FDD) cloud radio access network (C-RAN), the performance of PHY security highly relies on the channel state information (CSI) which is usually acquired through the codebook-quantization-based technique at the transceiver. However, the conventional quantization method aggravates the leakage of privacy information in C-RAN under the eavesdropping environment. In this paper, a novel channel quantization method is investigated to improve the secrecy-rate performance of C-RAN by exploiting the high-dimension space geometry. Based on this method, it is proved that when the statistical distribution of the channel matrices of both the legitimate user and the eavesdropper is exploited, a win-win situation can be created where secrecy-rate gains are improved without sacrificing beamforming gains from the point of view of ergodic rate. Particularly, a secrecy-oriented criterion is devised to implement the proposed method for generating codebooks. Then a weighted Voronoi diagram (WVD) is formulated on the complex Grassmann manifold and finally, a vector quantization based algorithm is proposed to build up novel quantization codebooks iteratively. Simulation results further validate the superiority of our proposed codebooks over conventional codebooks in C-RAN systems.\",\n \"Title: Facial age estimation through self-paced learning\\nYear: 2017\\n\\nAbstract: This paper proposes an age estimation algorithm in Self-Paced Learning (SPL) framework. Facial samples in the training set inherently include both easy and complex images, which is caused by both the characteristic of age and the variation of pose or expression. Furthermore, by randomly hiding patches in face region, data with different difficulty levels can be gradually used by SPL, in which Convolution Neural Network (CNN) is trained to give the estimation. Alternative Optimization Strategy (AVO), for the weight of CNN and the latent weight in SPL regularizer, is adopted in SPL framework. Experiments show that the proposed algorithm is able to give an accurate results especially under pose and expression variation.\",\n \"Title: Impact Analysis of Temperature and Humidity Conditions on Electrochemical Sensor Response in Ambient Air Quality Monitoring.\\nYear: 2018\\n\\nAbstract: The increasing applications of low-cost air sensors promises more convenient and cost-effective systems for air monitoring in many places and under many conditions. However, the data quality from such systems has not been fully characterized and may not meet user expectations in research and regulatory uses, or for use in citizen science. In our study, electrochemical sensors (Alphasense B4 series) for carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and oxidants (O-x) were evaluated under controlled laboratory conditions to identify the influencing factors and quantify their relation with sensor outputs. Based on the laboratory tests, we developed different correction methods to compensate for the impact of ambient conditions. Further, the sensors were assembled into a monitoring system and tested in ambient conditions in Hong Kong side-by-side with regulatory reference monitors, and data from these tests were used to evaluate the performance of the models, to refine them, and validate their applicability in variable ambient conditions in the field. The more comprehensive correction models demonstrated enhanced performance when compared with uncorrected data. One over-arching observation of this study is that the low-cost sensors may promise excellent sensitivity and performance, but it is essential for users to understand and account for several key factors that may strongly affect the nature of sensor data. In this paper, we also evaluated factors of multi-month stability, temperature, and humidity, and considered the interaction of oxidant gases NO2 and ozone on a newly introduced oxidant sensor.\",\n \"Title: Learning Monocular Visual Odometry With Dense 3d Mapping From Dense 3d Flow\\nYear: 2018\\n\\nAbstract: This paper introduces a fully deep learning approach to monocular SLAM, which can perform simultaneous localization using a neural network for learning visual odometry (L-VO) and dense 3D mapping. Dense 2D flow and a depth image are generated from monocular images by sub-networks, which are then used by a 3D flow associated layer in the L-VO network to generate dense 3D flow. Given this 3D flow, the dual-stream L-VO network can then predict the 6DOF relative pose and furthermore reconstruct the vehicle trajectory. In order to learn the correlation between motion directions, the Bivariate Gaussian modeling is employed in the loss function. The L-VO network achieves an overall performance of 2:68% for average translational error and 0.0143 degrees/m for average rotational error on the KITTI odometry benchmark. Moreover, the learned depth is leveraged to generate a dense 3D map. As a result, an entire visual SLAM system, that is, learning monocular odometry combined with dense 3D mapping, is achieved.\",\n \"Title: Age Estimation via Pose-Invariant 3D Face Alignment Feature in 3 Streams of CNN.\\nYear: 2017\\n\\nAbstract: This paper proposes an algorithm for age estimation intentionally considering the pose variation and local deformation of faces. Pose-invariant patches are extracted in face region, and they are located from the landmarks' neighborhood in 2D image coordinate. The landmarks can be regarded as the projections of the points on 3D face model, and the projection parameters are estimated by Convolution Neural Network (CNN). Two different structures of CNN are designed for age estimation task. One way is to stack individual patch in the spatial domain, and the stacked image is given to a CNN to make the estimation. The second is to design CNN for each particular patch and CNNs for different patches do not share weights. Together with another CNN trained on the original face region, the three streams for age estimation are combined by late fusion of the output layer. Experiments show that the proposed scheme outperforms other state-of-the-art methods.\",\n \"Title: An Approach for Setting Parameters for Two-Degree-of-Freedom PID Controllers.\\nYear: 2018\\n\\nAbstract: In this paper, a new tuning method is proposed, based on the desired dynamics equation (DDE) and the generalized frequency method (GFM), for a two-degree-of-freedom proportional-integral-derivative (PID) controller. The DDE method builds a quantitative relationship between the performance and the two-degree-of-freedom PID controller parameters and guarantees the desired dynamic, but it cannot guarantee the stability margin. So, we have developed the proposed tuning method, which guarantees not only the desired dynamic but also the stability margin. Based on the DDE and the GFM, several simple formulas are deduced to calculate directly the controller parameters. In addition, it performs almost no overshooting setpoint response. Compared with Panagopoulos' method, the proposed methodology is proven to be effective.\",\n \"Title: Scale-Invariant Wave Kernel Signature for Non-Rigid 3D Shape Retrieval\\nYear: 2018\\n\\nAbstract: The number of non-rigid 3D shapes increases steadily in various areas. It is imperative to develop efficient retrieval system for 3D non-rigid shapes. The wave kernel signature was introduced as an intrinsic local shape descriptor based on the wave function, which represents the average probability of a quantum mechanical particle at a specific location. In this paper, we develop a scale-invariant wave kernel signature normalizing with eigenvalues of the Laplace-Beltrami operator. The proposed descriptor is useful in coping with 3D shapes which have undergone scale transformation. Experimental results on public benchmarks show that our method outperforms the method based on the wave kernel signature for non-rigid 3D shape retrieval.\",\n \"Title: Security-Aware Waveform and Artificial Noise Design for Time-Reversal-Based Transmission.\\nYear: 2018\\n\\nAbstract: Among the plenty of studies on physical layer security, multi-antenna signal processing and nodes cooperation are two widely adopted techniques. However, in practical systems there are many single-antenna devices that do not support cooperative transmission either. To guarantee the information security in this scenario, we propose a novel transmission strategy that exploits the temporal characteri...\",\n \"Title: Fountain-Coding Aided Symmetrical Encryption for Secure Wireless Transmission.\\nYear: 2017\\n\\nAbstract: It is difficult to ensure secure transmissions in wireless networks because of the openness of radio signal. In this paper, a fountain-coding aided symmetrical encryption scheme is proposed to deal with this problem. In the proposed scheme, all source packets are first encrypted with a secret key. Then, all encrypted source packets are encoded with fountain code and next transmitted on wireless channels. Finally, the secret key is encrypted with all the fountain-coded packets the legitimate receiver has received for sharing the secret key between the legitimate users. Due to the independent fading characteristic between the legitimate channel and the wiretap channel, if the eavesdropper fails to correctly receive some fountain-coded packets the legitimate receiver receives, the wireless transmission can be secured under appropriate conditions. Compared with the counterparts, the proposed scheme achieves lower intercept probability of the eavesdropper with little receiver feedback burden under appropriate conditions.\",\n \"Title: Traffic-Driven Intrusion Detection For Massive Mtc Towards 5g Networks\\nYear: 2018\\n\\nAbstract: Massive machine type communications (MTC) have been proposed to be one of the major scenarios in 5G networks, which play the role of supporting future IoT towards ubiquitous information acquisition and exchange. Due to the requirement on low-cost devices, the requirement on anti-intrusion security calls for dedicated research efforts. To meet the MTC security requirements, some security enhancement techniques have been proposed, i.e., the evolved packet system-authentication and key agreement (EPS-AKA). However, with the growth of malicious devices's computing capability and attack ability, security protocol applied on high layer faces more threats and challenges, and even become much less effective. In this paper, we take the essential nature of traffic characteristics into consideration and establish the framework of intrusion detection for massive MTC networks. Then, we propose a traffic-driven intrusion detection scheme, the innovations of which contain two folds: 1) effective estimation of traffic arrival process based on Markovian chain and air-interface access statuses; 2) low-latency yet accurate decision criterion. We also conduct abundant simulations to evaluate our scheme's performances. Simulation results demonstrate that our scheme can well track the arrival process with high accuracy, outperforming the baseline schemes in terms of the not only the detection probability but also the detection time.\",\n \"Title: Efficient 3D Object Retrieval Based on Compact Views and Hamming Embedding.\\nYear: 2018\\n\\nAbstract: View-based 3-D object retrieval techniques have been increasingly important in various applications of computer vision. In this paper, we present a novel framework for view-based 3-D object retrieval. First, we exclude the background of views to avoid the disturbance of background noise. Then for these views, we extract the domain-size pooled SIFT descriptor features and encode them using approximate K-means algorithm. After quantizing each object with the approximate near neighbor, the hamming embedding is applied to refine the descriptors by adding binary signatures. Finally, we use the hamming matching to measure the similarity between two 3-D objects. A large number of experiments are performed on the ETH-80 benchmark. Compared with the state-of-art methods, the proposed method is demonstrated to be effective and robust.\",\n \"Title: Recurrent-Octomap: Learning State-Based Map Refinement For Long-Term Semantic Mapping With 3-D-Lidar Data\\nYear: 2018\\n\\nAbstract: This letter presents a novel semantic mapping approach, Recurrent-OctoMap, learned from long-term three-dimensional (3-D) Lidar data. Most existing semantic mapping approaches focus on improving semantic understanding of single frames, rather than 3-D refinement of semantic maps (i.e. fusing semantic observations). The most widely used approach for the 3-D semantic map refinement is \\\"Bayes update,\\\" which fuses the consecutive predictive probabilities following a Markov-chain model. Instead, we propose a learning approach to fuse the semantic features, rather than simply fusing predictions from a classifier. In our approach, we represent and maintain our 3-D map as an OctoMap, and model each cell as a recurrent neural network, to obtain a Recurrent-OctoMap. In this case, the semantic mapping process can he formulated as a sequence-to-sequence encoding-decoding problem. Moreover, in order to extend the duration of observations in our Recurrent-OctoMap, we developed a robust 3-D localization and mapping system for successively mapping a dynamic environment using more than two weeks of data, and the system can he trained and deployed with arbitrary memory length. We validate our approach on the ETH long-term 3-D Lidar dataset. The experimental results show that our proposed approach outperforms the conventional \\\"Bayes update\\\" approach.\",\n \"Title: Voltage And Fuel Utilization Control For Solid Oxide Fuel Cells With Combined L1 Adaptive - Predictive Control Strategy\\nYear: 2018\\n\\nAbstract: Output voltage and fuel utilization control of Solid Oxide Fuel Cells (SOFCs) is challenging due to large inertia, nonlinearity and safety related constraints associated with the system. The academic community seeks to solve this problem by resorting to Model Predictive Control (MPC), which is convenient to formulate the difficulties in its receding horizon optimization problem. However, the high demand of MPC for online computation limits its application in practical engineering. In this paper, a combined control strategy with MPC and L1 adaptive control (L1AC) is proposed to handle the control difficulties in SOFC with acceptable computation cost. The L1AC compensates the system nonlinearity and disturbances as lumped uncertainty, with guaranteed performance and then provide an ideal linear model for MPC. Then MPC provides optimal control signal with all the system constraints satisfied. The simulation result shows the proposed control system has good performance of regulation and disturbance rejection. The computation time for MPC is much less than the sampling time and is capable of practical application.\",\n \"Title: Secure Cooperative Communication With Nondedicated Relays.\\nYear: 2018\\n\\nAbstract: The security issue is considered for a cooperative communication system with multiple nondedicated relays, which have their own information to transmit. Distributed spatial modulation (DSM) is a promising technique for nondedicated relay networks. However, any receiver in the relays' coverage can decode the source information by examining the status of the relays in conventional DSM systems. To pr...\",\n \"Title: Outlier Data Treatment Methods Toward Smart Grid Applications.\\nYear: 2018\\n\\nAbstract: In a smart grid environment, advanced metering infrastructure (AMI) and intelligent sensors have been deployed extensively. As a result, large-scale and fine-grained smart grid data are more convenient to be collected, in which outliers exist pervasively, caused by system failures, environmental effects, and human interventions. Outlier deletion is always implemented in data preprocessing for improving data quality. However, due to the fact that real records that reflect rare and unusual patterns are also recognized as outliers, outlier mining is necessary to be carried out with the aim of discovering knowledge on abnormal patterns in power generation, transmission, distribution, transformation, and consumption. To the best of our knowledge, a comprehensive and systematic review of outlier data treatment methods is still lacked in the smart grid environment. We, in this paper, aim at presenting the review of outlier data treatment methods toward smart grid applications and categorize them into outlier rejection and outlier mining groups. Since we do this survey from the perspective of data-driven analytics and data mining methods, information security technologies are barely discussed in this paper. Based on a general overview of outlier data treatment methods, we make the contribution of providing the application scenarios of outlier rejection and outlier mining in the smart grid environment. With the construction of smart grid throughout the world, dealing with outlier data has become more crucial for the security and reliability of power system operation. Therefore, we also discuss some future challenges of outlier data treatment toward smart energy management.\",\n \"Title: Ecg Delineation With Randomly Selected Wavelet Feature And Random Forest Classifier\\nYear: 2018\\n\\nAbstract: Objective: Detection of Electrocardiogram (ECG) characteristic points can provide critical diagnostic information about heart diseases. We proposed a novel feature extraction and machine learning scheme for automatic detection of ECG characteristic points. Methods: A new feature, termed as randomly selected wavelet transform (RSWT) feature, was devised to represent ECG characteristic points. A random forest classifier was adapted to infer the characteristic points position with high sensitivity and precision. Results: Compared with other state-of-the-art algorithms' testing results on QT database, our detection results of RSWT scheme showed comparable performance (similar sensitivity, precision, and detection error for each characteristic point). RSWT testing on MIT-BIH database also demonstrated promising cross-database performance. Conclusion: A novel RSWT feature and a new detection scheme was fabricated for ECG characteristic points. The RSWT demonstrated a robust and trustworthy feature for representing ECG morphologies. Significance: With the effectiveness of the proposed RSWT feature we presented a novel machine learning based scheme to automatically detect all types of ECG characteristic points at a time. Furthermore, it showed that our algorithm achieved better performance than other reported machine learning based methods.\",\n \"Title: Design in Power-Domain NOMA: Eavesdropping Suppression in the Two-User Relay Network with Compensation for the Relay User.\\nYear: 2018\\n\\nAbstract: Non-orthogonal multiple access (NOMA) is becoming important in 5G, therefore, it is widely researched. Note that the users served in NOMA are often paired to prevent excessive interference. However, if the channel condition of direct downlink from the service node to one user is serious, the node may require the other user with better channel condition to relay this user’s signals, especially when the pure relay is difficult to deploy. This relay transmission is helpful for NOMA communication, but two problems should be considered: (i) how to persuade the relay user (i.e., the user with better channel condition) to expend extra resources for relay; (ii) how to suppress eavesdropping in the relay transmission, especially for the signals of indirect communication user (i.e., the user with worse channel condition). To solve these problems, we propose a novel signal-level scheme. In this scheme, on one hand, the node increases the spectral efficiency of relay user, and does the wireless power transfer to make the relay user supplement his/her energy by energy harvesting. On the other hand, a signal transformation method is designed to deal with each signal of indirect communication user. This transformation hides privacy information of indirect communication user, but does not disrupt the relay transmission. Utilizing the proposed scheme, the above problems are effectively solved by the compensation for the relay user and the signal protection for the indirect communication user.\",\n \"Title: Structure-Aware Staging For Breast Cancer Metastases\\nYear: 2018\\n\\nAbstract: Determining the stage of breast cancer metastases is an important component of cancer surveillance and control. It is laborious for pathologist to manually examine large amount of biological tissue and this process is error-prone. Deep learning methods can be used to automatically detect cancer metastases and identify cancer subtypes. However, current deep learning-based methods mainly focus on local patches but ignore the overall structure of lymph tissue, due to the memory limitation and computational cost of processing the gigapixel whole slide histopathological image (WSI) at a time. In this paper, we propose a structure-aware deep learning framework for staging of breast cancer metastases, in which we introduce lymph structure information to guide training patch selection and prediction features design. Our approach achieves 85.1% accuracy on slide-level and 0.80 kappa score on patient level. In addition, we see 6.1% and 5% performance gain on slide level and patient level classification respectively after introducing global structure information.\",\n \"Title: Deformable MRI-Ultrasound Registration Using 3D Convolutional Neural Network.\\nYear: 2018\\n\\nAbstract: Precise tracking of intra-operative tissue shift is important for accurate resection of brain tumor. Alignment of pre-interventional magnetic resonance imaging (MRI) to intra-operative ultrasound (iUS) is required to access tissue shift and enable guided surgery. However, accurate and robust image registration needed to relate pre-interventional MRI to iUS images is difficult due to the very different nature of image intensity between modalities. Here we present a framework that can perform non-rigid MRI-ultrasound registration using 3D convolutional neural network (CNN). The framework is composed of three components: feature extractor, deformation field generator and spatial sampler. Our automatic registration framework adopts unsupervised learning approach, allows accurate end-to-end deformable MRI-ultrasound registration. Our proposed method avoids the downfall of intensity-based methods by considering both image intensity and gradient. It achieves competitive registration accuracy on RESECT dataset. In addition, our method takes only about one second to register each image pair, enabling applications such as real time registration.\",\n \"Title: Pancreatic Cancer Survival Prediction Using CT Scans and Clinical Variables.\\nYear: 2018\\n\\nAbstract: Pancreatic cancer resulted in 411,600 deaths globally in 2015. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and it is highly lethal. Survival for patients with PDAC is dismal due to its aggressive nature, thus the development of novel and reliable prognostic model for early detection and therapy is much desired. Here we proposed a prognostic framework for prediction of overall survival of PDAC patients based on predictors derived from pancreas CT scans and patient clinical variables. Our framework includes three parts: feature extraction, feature selection and survival prediction. First, 2436 radiomics features were extracted from CT scans and were combined with the clinical variables, and a Cox model was fitted to each covariate individually to select the most predictive features. The optimal cut-off was determined by cross-validation. Finally, gradient boosting with component-wise Cox's proportional hazards model was utilized to predict the overall survival of patients. Our framework achieves excellent performance on MICCAI 2018 Pancreatic Cancer Survival Prediction Challenge dataset, achieving mean concordance index of 0.7016 using five-fold cross-validation.\",\n \"Title: Unequal Secrecy Protection for Untrusted Two-Way Relaying Systems: Constellation Overlapping and Noise Aggregation.\\nYear: 2018\\n\\nAbstract: This paper studies the secure information exchange of two-way relaying systems, where two terminal users communicate bi-directionally with the assistance of an untrusted relay. Each user is assumed to have two messages with distinct priorities: high priority and low priority. The high-priority messages (HPM) are first transmitted, for which we propose a constellation overlapping scheme such that t...\",\n \"Title: A security scheme of digital rights management based on agent encryption and key distribution in cloud computing.\\nYear: 2018\\n\\nAbstract: Cloud computing is a convenient and flexible mode of data transmission and sharing. Data security is the biggest challenge today owing to the wide application of cloud computing in various fields. This study proposed a security scheme of digital rights management based on digital license and agent encryption in cloud computing. First, a secure and effective framework of digital rights management was presented, allowing the agent encryption provider (such as centralised data server) to encrypt the data content and the common users to use the data resource based on digital license generated by a license server. The novel scheme could accomplish the privacy protection by permitting anonymous users to request different services from the key server and service provider. The performance analysis showed that the proposed scheme could assure the security and efficiency of data resource, thereby establishing its significance and application value for promoting a widespread application of cloud computing.\",\n \"Title: Exploring Correlations in Multiple Facial Attributes through Graph Attention Network.\\nYear: 2018\\n\\nAbstract: Estimating multiple attributes from a single facial image gives comprehensive descriptions on the high level semantics of the face. It is naturally regarded as a multi-task supervised learning problem with a single deep CNN, in which lower layers are shared, and higher ones are task-dependent with the multi-branch structure. Within the traditional deep multi-task learning (DMTL) framework, this paper intends to fully exploit the correlations among different attributes by constructing a graph. The node in graph represents the feature vector from a particular branch for a given attribute, and the edge can be defined by either the prior knowledge or the similarity between two nodes in the embedding with a fully data-driven manner. We analyze that the attention mechanism actually takes effect in the latter case, and utilize the Graph Attention Layer (GAL) for exploring on the most relevant attribute feature and refining the task-dependant feature by considering other attributes. Experiments show that by mining the correlations among attributes, our method can improve the recognition accuracy on CelebA and LFWA dataset. And it also achieves competitive performance.\",\n \"Title: Discriminating ADHD From Healthy Controls Using a Novel Feature Selection Method Based on Relative Importance and Ensemble Learning.\\nYear: 2018\\n\\nAbstract: Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder that often persists into adulthood, resulting in adverse effects on work performance and social function. The current diagnosis of ADHD primarily depends on the judgment of clinical symptoms, which highlights the need for objective imaging biomarkers. In this study, we aim to classify ADHD (both children and adults [34/112]) from age-matched healthy controls (HCs [28/77]) with functional connectivity (FCs) pattern derived from resting-state functional magnetic resonance imaging (rs-fMRI) data. However, the neuroimaging classification of brain disorders often meets a situation of high dimensional features were presented with limited sample size. Thus an efficient method that is able to reduce original feature dimension into a much more refined subspace is highly desired. Here we proposed a novel Feature Selection method based on Relative Importance and Ensemble Learning (FS_RIEL). Compared with traditional feature selection methods, FS_RIEL algorithm improved the ADHD classification by about 15% in both child and adult ADHD classification, achieving 80-86% accuracy. Moreover, we found the most frequently selected FCs were mainly involved in frontoparietal network, default network, salience network, basal ganglia network and cerebellum network in both child and adult ADHD cohorts, which indicates that ADHD is characterized by a widely-impaired brain connectivity profile that may serve as potential biomarkers for its early diagnosis.\",\n \"Title: Saliency Detection for $\\\\mathbf{L}_{1/2}$ Regularization-Based SAR Image Feature Enhancement Via Bayesian Inference.\\nYear: 2018\\n\\nAbstract: The sparse images reconstructed by conventional $mathrm{L}_{q} (0 regularization-based SAR imaging method cannot preserve the image background distribution, thus bring new challenges in SAR target detection. In this paper, we proposed a new saliency detection method for $mathrm{L}_{1/2}$ regularization-based SAR image feature enhancement. Compared with traditional saliency detection methods, our method can obtain more smooth structures and higher intensity of the bright objects, thus can obtain better target detection results. The experimental results on the miniSAR real dataset show the effective of the proposed method.\",\n \"Title: A novel forwarding and routing mechanism design in SDN-based NDN architecture.\\nYear: 2018\\n\\nAbstract: Combining named data networking (NDN) and software-defined networking (SDN) has been considered as an important trend and attracted a lot of attention in recent years. Although much work has been carried out on the integration of NDN and SDN, the forwarding mechanism to solve the inherent problems caused by the flooding scheme and discard of interest packets in traditional NDN is not well considered. To fill this gap, by taking advantage of SDN, we design a novel forwarding mechanism in NDN architecture with distributed controllers, where routing decisions are made globally. Then we show how the forwarding mechanism is operated for interest and data packets. In addition, we propose a novel routing algorithm considering quality of service (QoS) applied in the proposed forwarding mechanism and carried out in controllers. We take both resource consumption and network load balancing into consideration and introduce a genetic algorithm (GA) to solve the QoS constrained routing problem using global network information. Simulation results are presented to demonstrate the performance of the proposed routing scheme.\",\n \"Title: Integrating Deep Semantic Segmentation Into 3-D Point Cloud Registration.\\nYear: 2018\\n\\nAbstract: Point cloud registration is the task of aligning 3D scans of the same environment captured from different poses. When semantic information is available for the points, it can be used as a prior in the search for correspondences to improve registration. Semantic-assisted Normal Distributions Transform (SE-NDT) is a new registration algorithm that reduces the complexity of the problem by using the s...\",\n \"Title: Amalgamating Knowledge towards Comprehensive Classification\\nYear: 2018\\n\\nAbstract: With the rapid development of deep learning, there have been an unprecedentedly large number of trained deep network models available online. Reusing such trained models can significantly reduce the cost of training the new models from scratch, if not infeasible at all as the annotations used for the training original networks are often unavailable to public. We propose in this paper to study a new model-reusing task, which we term as knowledge amalgamation. Given multiple trained teacher networks, each of which specializes in a different classification problem, the goal of knowledge amalgamation is to learn a lightweight student model capable of handling the comprehensive classification. We assume no other annotations except the outputs from the teacher models are available, and thus focus on extracting and amalgamating knowledge from the multiple teachers. To this end, we propose a pilot two-step strategy to tackle the knowledge amalgamation task, by learning first the compact feature representations from teachers and then the network parameters in a layer-wise manner so as to build the student model. We apply this approach to four public datasets and obtain very encouraging results: even without any human annotation, the obtained student model is competent to handle the comprehensive classification task and in most cases outperforms the teachers in individual sub-tasks.\",\n \"Title: A Review of Physical Layer Security Techniques for Internet of Things: Challenges and Solutions.\\nYear: 2018\\n\\nAbstract: With the uninterrupted revolution of communications technologies and the great-leap-forward development of emerging applications, the ubiquitous deployment of Internet of Things (IoT) is imperative to accommodate constantly growing user demands and market scales. Communication security is critically important for the operations of IoT. Among the communication security provisioning techniques, physical layer security (PLS), which can provide unbreakable, provable, and quantifiable secrecy from an information-theoretical point of view, has drawn considerable attention from both the academia and the industries. However, the unique features of IoT, such as low-cost, wide-range coverage, massive connection, and diversified services, impose great challenges for the PLS protocol design in IoT. In this article, we present a comprehensive review of the PLS techniques toward IoT applications. The basic principle of PLS is first briefly introduced, followed by the survey of the existing PLS techniques. Afterwards, the characteristics of IoT are identified, based on which the challenges faced by PLS protocol design are summarized. Then, three newly-proposed PLS solutions are highlighted, which match the features of IoT well and are expected to be applied in the near future. Finally, we conclude the paper and point out some further research directions.\",\n \"Title: Encryption Over the Air: Securing Two-Way Untrusted Relaying Systems Through Constellation Overlapping.\\nYear: 2018\\n\\nAbstract: This paper proposes a novel technique called constellation overlapping to secure two-way untrusted relaying systems. We first consider the symmetric case where two terminal users adopt the same modulation type. For this case, a truncated-channel-inversion-based approach is developed to make the signals from different users experience the same equivalent channel, thereby realizing full constellatio...\",\n \"Title: Multi-Model Feedforward Dynamic Matrix Control Of Polymer Membrane Fuel Cell With Dead-Ended Anode And Cyclic Purge Process\\nYear: 2018\\n\\nAbstract: This paper proposes a control strategy for a Polymer Electrolyte Membrane Fuel Cell (PEMFC) with a dead-ended anode (DEA) and cyclic purge process using Multi-model Feedforward Dynamic Matrix Control (MFDMC) with a switch law. MFDMC is a model-based predictive control method, which has superiority in addressing control problems with constraints and nonlinearity. The control objective is to maintain a low differential pressure across the membrane against the disturbance of the purge process and load change. A mathematical model is built and its dynamics is recognized at varied operating conditions to demonstrate the transient behavior of a PEMFC stack Simulation results show the ability of the MFDMC to compensate the influence of periodic purging and load change without constraint violation of the actuator.\",\n \"Title: Method of Synthesizing Orthogonal Beam-Forming Networks Using QR Decomposition.\\nYear: 2019\\n\\nAbstract: A synthesis method for orthogonal beam-forming networks (BFNs) with arbitrary N inputs and N outputs is presented. Compared to those formerly developed, the new method allows the design of a BFN in order to not only generate arbitrary N orthogonal beams and N inputs but also to make the 180° hybrids less. This skill is obtained by means of a new approach to decompose the matrices $Q_{1}$ and $Q...\",\n \"Title: Multisensor Online Transfer Learning For 3d Lidar-Based Human Detection With A Mobile Robot\\nYear: 2018\\n\\nAbstract: Human detection and tracking is an essential task for service robots, where the combined use of multiple sensors has potential advantages that are yet to be fully exploited. In this paper, we introduce a framework allowing a robot to learn a new 3D LiDAR-based human classifier from other sensors over time, taking advantage of a multisensor tracking system. The main innovation is the use of different detectors for existing sensors (i.e. RGB-D camera, 2D LiDAR) to train, online, a new 3D LiDAR-based human classifier based on a new \\\"trajectory probability\\\". Our framework uses this probability to check whether new detection belongs to a human trajectory, estimated by different sensors and/or detectors, and to learn a human classifier in a semi-supervised fashion. The framework has been implemented and tested on a real-world dataset collected by a mobile robot. We present experiments illustrating that our system is able to effectively learn from different sensors and from the environment, and that the performance of the 3D LiDAR-based human classification improves with the number of sensors/detectors used.\",\n \"Title: A Data Reuse Method for Fast Search Motion Estimation.\\nYear: 2018\\n\\nAbstract: In motion estimation, the search regions of two adjacent current blocks have overlapping data. In view of this, the paper proposes a data reuse method for fast search motion estimation. The method reuses the overlapping data between the search areas of two adjacent blocks. The overlapping data are further divided into two parts, a definite data reuse area and a possible data reuse area. With this method, the memory access time of the algorithm is reduced, and the performance of the algorithm is further improved. And the proposed reuse method can effectively reduce the loading of redundant data. A typical fast search algorithm, diamond search, is used as a case study to verify the effectiveness of the method. The method is implemented on GPU platform. The experimental results show that the data reuse method can reduce the running time by 40%–60% compared with the algorithm of no use data reuse.\",\n \"Title: Information To Intelligence(Itoi): An Adaptive And Intelligent Prototype Of Knowledge Construction For College Student\\nYear: 2018\\n\\nAbstract: An adaptive and intelligent prototype of knowledge construction for college students, information to Intelligence(itoI), is proposed in this paper. During the process of knowledge construction, the system records all kinds of online study performance of each student, and then interdisciplinary coursework is automatically assigned to the right students. Both the student and the system improve their knowledge level and intelligence level adaptively. Through the random survey on college student of Shandong Normal University, the results show that it is useful for guiding the process of online learning.\",\n \"Title: Instantaneous Power Control Of A High Speed Permanent Magnet Synchronous Generator Based On A Sliding Mode Observer And A Phase Locked Loop\\nYear: 2017\\n\\nAbstract: This paper proposes an instantaneous power control method for high speed permanent magnet synchronous generators (PMSG), to realize the decoupled control of active power and reactive power, through vector control based on a sliding mode observer (SMO), and a phase locked loop (PLL). Consequently, the high speed PMSG has a high internal power factor, to ensure efficient operation. Vector control and accurate estimation of the instantaneous power require an accurate estimate of the rotor position. The SMO is able to estimate the back electromotive force (EMF). The rotor position and speed can be obtained using a combination of the PLL technique and the phase compensation method. This method has the advantages of robust operation, and being resistant to noise when estimating the position of the rotor. Using instantaneous power theory, the relationship between the output active power, reactive power, and stator current of the PMSG is deduced, and the power constraint condition is analysed for operation at the unit internal power factor. Finally, the accuracy of the rotor position detection, the instantaneous power detection, and the control methods are verified using simulations and experiments.\",\n \"Title: Fountain-Coding-Based Secure Communications Exploiting Outage Prediction and Limited Feedback.\\nYear: 2019\\n\\nAbstract: This paper develops a fountain-coding-based scheme to secure communications over fading wiretap channels, in which the transmission between the legitimate nodes is overheard by a malicious eavesdropper. The transmitter first splits its message into K source packets and generates a potentially infinite number of fountain-coded packets, each of which is the XOR of distinct source packets chosen acco...\",\n \"Title: Segmentation Of Pathological Features Of Rat Bile Duct Carcinoma From Hyperspectral Images\\nYear: 2018\\n\\nAbstract: Liver disease has always been one of the key concerns of the medical community. In recent years, liver diagnostic techniques such as serology have been continuously developed, but the pathological diagnosis of the liver, especially the advancement of liver biopsy technology, is still the most reliable basis for the diagnosis and treatment of liver diseases. In this paper, pathological sections of rat bile duct carcinoma were used as experimental samples to identify and analyze liver tumor by microscopic hyperspectral imaging (MHSI) technique. The proposed method combines the Otsu (OTSU) algorithm with the support vector machine (SVM) algorithm to segment the liver tumor, and comparing with SVM segmentation results. Experimental results show that the OTSU-SVM method has an accuracy of 94.59% which provides a potential reference value for the pathological diagnosis of liver tumors.\",\n \"Title: Detection Of Mycobacterium Tuberculosis In Ziehl-Neelsen Sputum Smear Images\\nYear: 2018\\n\\nAbstract: Tuberculosis is one of the top 10 causes of death worldwide. In order to reduce the workload of doctors and the probability of human error, this paper presents an automatic detection algorithm for Mycobacterium tuberculosis in Ziehl-Neelsen Sputum Smear Images. The algorithm uses color feature and three morphological characters, which are aspect ratio, circularity and area. Background Equalization algorithm is proposed to utilize color feature sufficiently. This algorithm takes advantage of the watershed algorithm and the channel \\\"a\\\" in Lab color space. Experimental results accuracy of the proposed algorithm.\",\n \"Title: Autonomous Clothes Manipulation Using a Hierarchical Vision Architecture.\\nYear: 2018\\n\\nAbstract: This paper presents a novel robot vision architecture for perceiving generic 3-D clothes configurations. Our architecture is hierarchically structured, starting from low-level curvature features to mid-level geometric shapes and topology descriptions, and finally, high-level semantic surface descriptions. We demonstrate our robot vision architecture in a customized dual-arm industrial robot with our in-house developed stereo vision system, carrying out autonomous grasping and dual-arm flattening. The experimental results show the effectiveness of the proposed dual-arm flattening using the stereo vision system compared with the single-arm flattening using the widely cited Kinect-like sensor as the baseline. In addition, the proposed grasping approach achieves satisfactory performance when grasping various kind of garments, verifying the capability of the proposed visual perception architecture to be adapted to more than one clothing manipulation tasks.\",\n \"Title: Disentangling Latent Space For Vae By Label Relevant/Irrelevant Dimensions\\nYear: 2018\\n\\nAbstract: VAE requires the standard Gaussian distribution as a prior in the latent space. Since all codes tend to follow the same prior, it often suffers the so-called \\\"posterior collapse\\\". To avoid this, this paper introduces the class specific distribution for the latent code. But different from cVAE, we present a method for disentangling the latent space into the label relevant and irrelevant dimensions, z(s) and z(u), for a single input. We apply two separated encoders to map the input into z(s) and z(u) respectively, and then give the concatenated code to the decoder to reconstruct the input. The label irrelevant code zu represent the common characteristics of all inputs, hence they are constrained by the standard Gaussian, and their encoder is trained in amortized variational inference way, like VAE. While z(s) is assumed to follow the Gaussian mixture distribution in which each component corresponds to a particular class. The parameters for the Gaussian components in z(s) encoder are optimized by the label supervision in a global stochastic way. In theory, we show that our method is actually equivalent to adding a KL divergence term on the joint distribution of z(s) and the class label c, and it can directly increase the mutual information between z(s) and the label c. Our model can also be extended to GAN by adding a discriminator in the pixel domain so that it produces high quality and diverse images.\",\n \"Title: A Multi-Dimensional Hyperspectral Image Mosaic Method and its Acquisition System.\\nYear: 2018\\n\\nAbstract: With the combination of both spectral and spatial information, hyperspectral images can offer much detailed information for researchers. In this paper, a multi-dimensional hyperspectral image mosaic method has been proposed to stitch hyperspectral images. This method combines texture information of the single gray image, spatial information of the hyperspectral image and the position information gathered during the acquisition process. We apply this method to the medical hyperspectral image stitch and the experimental results prove the accuracy of this method compared to other single-dimensional methods.\",\n \"Title: Development of 3D Exhibition System for IoT-Oriented Simulation Platform.\\nYear: 2018\\n\\nAbstract: This paper develops an exhibition system based on the system-level simulation platform for massive wireless access of IoT. The system appends a complete data output mechanism based on the original simulation platform, which provides a convenient environment for development and debugging, observation of system process and performance evaluation for the NB-IoT simulation platform. The exhibition system includes multiple modules, such as a data processing module, a driving engine module, a drawing module and a 3D scene module. Meanwhile, the system designs multiple interaction modules to restore the simulation details. Finally, this paper completes the debugging of the system, analyzes and discusses the results.\",\n \"Title: An innovative control strategy for a hybrid energy storage system (HESS)\\nYear: 2017\\n\\nAbstract: Electric Vehicles (EVs) adopting both batteries and supercapacitors have attracted a significant amount of attention in research communities due to its unique power sharing capabilities. A Hybrid Energy Storage System (HESS) can effectively reduce power stress that would otherwise be applied to batteries alone, and whose weight and size is still a common concern when competing against conventional ICE-powered cars. In this paper, a high-level control strategy is developed to adaptively split the load between two sources for an electric vehicle adopting HESS under real-life load fluctuations. A converter - Supercapacitor Pack (SP) coupled HESS upon which such an algorithm is deployed on, is proposed to divert excess power into the SP via a smart Power Converter (PC) which is located in between in order to regulate both behaviors. Such a power split strategy (PSS) is designed in such a way to track real-time load profiles and determines one important variable - the cut-off frequency. A simplified HESS model is first developed. The power split algorithm is coded in Matlab and then applied to this HESS model. Finally, the overall system is tested comprehensively over 4 EPA driving cycles. Simulation results prove its effectiveness in coping with even the harshest driving scenarios in real life.\",\n \"Title: On Secure Simple Pairing in Bluetooth Standard v5.0-Part I: Authenticated Link Key Security and Its Home Automation and Entertainment Applications.\\nYear: 2019\\n\\nAbstract: Bluetooth is an important technical standard for short-range and low-power wireless communication. The home automation and entertainment (HAE) systems often make use of Bluetooth technology to link different Bluetooth devices and form Bluetooth networks. The security concerns of the HAE systems are raised due to massive deployment of the Bluetooth devices. The Bluetooth standard mainly depends on the secure simple pairing (SSP) solution to protect the Bluetooth devices. Hence, we investigate the SSP solution according to the Bluetooth standard v5.0. The contributions are threefold. (1) A formal security model is proposed to evaluate SSP's association models and authenticated link key. (2) We formally analyze two SSP protocols and present the security requirements for basic cryptographic modules in these SSP protocols. (3) We discuss the typical SSP applications in the HAE systems. Our results are useful to not only evaluating and designing the SSP protocols but also enhancing the security of the HAE systems in which the Bluetooth access is available.\",\n \"Title: Microwave Non-Destructive Inspection and Prediction of Modulus of Rupture and Modulus of Elasticity of Engineered Cementitious Composites (ECCs) Using Dual-Frequency Correlation.\\nYear: 2017\\n\\nAbstract: This research article presents dual-frequency correlation models for predicting the growth of elasticity and flexural strength of engineered cementitious composites (ECCs) using microwave nondestructive inspection technique. Parallel measurements of microwave properties and mechanical properties of ECC specimens were firstly undertaken in the sense of cross-disciplinary experiments. Regression models were developed via means of nonlinear regression to the measured data. The purpose of the study is: (i) to monitor the flexural strength and elasticity growth; and (ii) to predict their mature values under the influence of different initial water contents, via microwave effective conductance at early ages. It has been demonstrated that both the modulus of rupture (MOR) and modulus of elasticity (MOE) can be accurately modeled and correlated by microwave conductance using exponential functions. The moduli developed as a function of conductance whereas the regression coefficient exhibited a linear relation with water-to-binder ratio. These findings have highlighted the effectiveness of the microwave non-destructive technique in inspecting the variation of liquid phase morphology of ECCs. The dual-frequency correlation can be used for structural health monitoring, which is not only for prediction but also provides a means of verification.\",\n \"Title: A Novel Parameter Determination Method for Lq Regularization Based Sparse SAR Imaging\\nYear: 2017\\n\\nAbstract: Sparse SAR imaging based on Lq(0 u003c q u003c 1) regularization has become a hot issue in SAR imaging. However, it can be difficult to determine a suitable value of the regularization parameter. In this paper, we developed a novel adaptive regularization parameter determination method for Lq regularization based SAR imaging. On the basis that the noise type in SAR system is mostly additive Gaussian white noise, we present a method for determining the regularization parameter through evaluating the statistics of noise. The parameter is updated through validating the statistical properties of the reconstruction error residuals in a suitable Noise Confidence Region (NCR). The experiment results illustrate the validity of the proposed method.\",\n \"Title: An Orthonormalized Basis Function Algorithm Based On Wavelet Analysis For Magnetic Anomaly Detection\\nYear: 2017\\n\\nAbstract: This Magnetic Anomaly Detection (MAD) technology is widely used in various fields in recent years. The focus of most researches is how to improve the signal recognition rate and reduce the false alarm rate. This paper presents an improved Orthonormalized Basis Function (OBF) algorithm for MAD in non-Gaussian noise background. In this algorithm, the raw signal is first decomposed by the wavelet. Then several layers of the decomposed signal with target characteristics are picked out as the reconstructed signal. Finally the magnetic target is recognized by the OBF algorithm. The experimental results show that the noise of the signal can be suppressed to a certain extent and the SNR is improved. Compared with the traditional OBF algorithm, the wavelet analysis based OBF algorithm can detect the target signal accurately and reduce the waste of resources caused by the false alarms.\",\n \"Title: Detection of 3-D objects with a 2-D laser scanning sensor for greenhouse spray applications.\\nYear: 2018\\n\\nAbstract: •Accuracy of an inexpensive laser scanning sensor for detecting objects was validated.•An algorithm was designed to measure object dimensions under various conditions.•Pseudo-color images were used to map surfaces of complex-shaped objects and plants.•Implementing the laser sensor to guide greenhouse spray applications were proposed.\",\n \"Title: A generic integrity verification algorithm of version files for cloud deduplication data storage\\nYear: 2018\\n\\nAbstract: Data owners’ outsourced data on cloud data storage servers by the deduplication technique can reduce not only their own storage cost but also cloud’s. This paradigm also introduces new security issues such as the potential threat of data lost or corrupted. Data integrity verification is utilized to safeguard these data integrity. However, the cloud deduplication storage only focuses on file/chunk level to store one copy of the same data hosted by different data owners, and is not concerned with the same part of different data, e.g., a series of version files. We propose an integrity verification algorithm of different version files. The algorithm establishes the generic storage model of different version control methods to improve the universality of data verification. Then, the methods of verification tags and proofs generating are improved based on the index pointers corresponding to the storage relationship in the version groups and chained keys. Finally, the random diffusion extraction based on the random data sampling in the version group is proposed to improve the verification efficiency. The results of theoretical and experimental analysis indicate that the algorithm can achieve fast and large-scale verification for different version data.\",\n \"Title: The Strain Transfer Mechanism of Fiber Bragg Grating Sensor for Extra Large Strain Monitoring.\\nYear: 2019\\n\\nAbstract: This research focuses on a desensitization method to develop a wide-range FBG sensor for extra-large strain monitoring, which is an essential requirement in large scale infrastructures or for some special occasions. Under appropriate hypotheses, the strain transfer distribution of wide-range FBG sensor based on the shear-lag theory is conducted to improve the accuracy of extra-large strain measurements. It is also discussed how the elastic modulus of adhesive layer affects the strain transfer rate. Two prototypes in different monitoring ranges are designed and fabricated by two layers of steel pipe encapsulation. The presented theoretical model is verified by experimental results. Moreover, it is demonstrated that experimentation in regards to the calibration of the wide-range FBG sensor, improved the amplification coefficient up to 2.08 times and 3.88 times, respectively. The static errors are both calculated and analyzed in this experiment. The wide-range FBG strain sensor shows favourable linearity and stability, which is an excellent property of sensors for extra-large strain monitoring.\",\n \"Title: A self-propelled robotic system with a visco-elastic joint: dynamics and motion analysis\\nYear: 2020\\n\\nAbstract: This paper studies the dynamics and motion generation of a self-propelled robotic system with a visco-elastic joint. The system is underactuated, legless and wheelless, and has potential applications in environmental inspection and operation in restricted spaces which are inaccessible to human beings, such as pipeline inspection, medical assistance and disaster rescue. Locomotion of the system relies on the stick–slip effects, which interacts with the frictional force of the surface in contact. The nonlinear robotic model utilizes combined tangential-wise and normal-wise vibrations for underactuated locomotion, which features a generic significance for the studies on self-propelled systems. To identify the characteristics of the visco-elastic joint and shed light on the energy efficacy, parameter dependences on stiffness and damping coefficients are thoroughly analysed. Our studies demonstrate that the dynamic behaviour of the self-propelled system is mainly periodic and desirable forward motion is achieved via identification of the variation laws of the control parameters and elaborate selection of the stiffness and damping coefficients. A motion generation strategy is developed, and an analytical two-stage motion profile is proposed based on the system response and dynamic constraint analysis, followed by a parameterization procedure to optimally generate the trajectory. The proposed method provides a novel approach in generating self-propelled locomotion, and designing and computing the visco-elastic parameters for energy efficacy. Simulation results are presented to demonstrate the effectiveness and feasibility of the proposed model and motion generation approach.\",\n \"Title: Spatio-temporal deep learning method for ADHD fMRI classification\\nYear: 2019\\n\\nAbstract: •Fusing spatial and temporal features is effective in fMRI classification.•Models considering sequence achieve better results than timing invariant models.•fMRI scans longer than one minute contain enough information for ADHD diagnosis.•deep-learned features outperform hand-crafted features in fMRI analysis.\",\n \"Title: Continuous perception for deformable objects understanding\\nYear: 2019\\n\\nAbstract: We present a robot vision approach to deformable object classification, with direct application to autonomous service robots. Our approach is based on the assumption that continuous perception provides robots with greater visual competence for deformable objects interpretation and classification. Our approach classifies the category of clothing items by continuously perceiving the dynamic interactions of the garment’s material and shape as it is being picked up. For this, we extract continuously visual features of a RGB-D video sequence and we fuse features by means of the Locality Constrained Group Sparse Representation (LGSR) algorithm. To evaluate the performance of our approach, we created a fully annotated database featuring 150 garment videos in random configurations. Experiments demonstrate that by continuously observing an object deform, our approach achieves a classification score of 66.7%, outperforming state-of-the-art approaches by a ∼27.3% increase.\",\n \"Title: Radar Signal Processing for Sensing in Assisted Living: The challenges associated with real-time implementation of emerging algorithms\\nYear: 2019\\n\\nAbstract: This article covers radar signal processing for sensing in the context of assisted living (AL). This is presented through three example applications: human activity recognition (HAR) for activities of daily living (ADL), respiratory disorders, and sleep stages (SSs) classification. The common challenge of classification is discussed within a framework of measurements/preprocessing, feature extraction, and classification algorithms for supervised learning. Then, the specific challenges of the three applications from a signal processing standpoint are detailed in their specific data processing and ad hoc classification strategies. Here, the focus is on recent trends in the field of activity recognition (multidomain, multimodal, and fusion), health-care applications based on vital signs (superresolution techniques), and comments related to outstanding challenges. Finally, this article explores challenges associated with the real-time implementation of signal processing/classification algorithms.\",\n \"Title: Dna: Dynamic Social Network Alignment\\nYear: 2019\\n\\nAbstract: Social network alignment, aligning different social networks on their common users, is receiving dramatic attention from both academic and industry. All existing studies consider the social network to be static and neglect its inherent dynamics. In fact, the dynamics of social networks contain the discriminative pattern of an individual, which can be leveraged to facilitate social network alignment. Hence, we for the first time propose to study the problem of aligning dynamic social networks. Towards this end, we propose a novel Dynamic social Network Alignment (DNA) framework, a unified optimization approach over deep neural architectures, to unfold the fruitful dynamics to perform alignment. However, it faces tremendous challenges in both modeling and optimization: (1) To model the intranetwork dynamics, we explore the local dynamics of the latent pattern in friending evolvement and the global consistency of the representation similarity with neighbors. We design a novel deep neural architecture to obtain the dual embedding capturing local dynamics and global consistency for each user. (2) To model the inter-network alignment, we exploit the underlying identity of an individual from the dual embedding in each dynamic social network. We design a unified optimization approach interplaying proposed deep neural architectures to construct a common subspace of identity embeddings. (3) To address this optimization problem, we design an effective alternating algorithm with solid theoretical guarantees. We conduct extensive experiments on realworld datasets and show that the proposed DNA framework substantially outperforms the state-of-the-art methods.\",\n \"Title: Deepblue: Bi-Layered Lstm For Tweet Popularity Estimation\\nYear: 2019\\n\\nAbstract: In social networks, one of the most significant challenges is how to estimate the tweet popularity. Prior studies about this problem focus on leveraging different aspects of just a single tweet, while ignoring the impact of historical tweets. In this paper, we propose to leverage such historical information and rethink the problem of tweet popularity estimation. From historical information, there are two important factors that can be extracted: (1) user reputation feature, which can represent coarse-grained level of tweet popularity; (2) tweet related features, which can represent fine-grained level of tweet popularity. To incorporate two factors from historical information, we design a novel deep neural architecture, a Bi-layered LSTM for tweet popUlarity Estimation, called DeepBlue. Specifically, we first propose a user-reputation aware mechanism to combine coarse-grained and fine-grained level estimation into a unified LSTM model. We then propose a time aware mechanism to address the time interval irregularity issue in standard LSTM. Finally, we apply the Poisson regression model to obtain the overall loss for tweet popularity estimation. Extensive experiments demonstrate the superiority of our proposed approach to other state-of-the-arts in terms of MAE and SRC.\",\n \"Title: Value-Aware Resampling And Loss For Imbalanced Classification\\nYear: 2018\\n\\nAbstract: Existing(1) machine learning methods usually treat training samples equally, and their performance degrades significantly when facing imbalanced training data. This paper introduces Value-Aware Resampling and Loss (VARL) to tackle the imbalanced classification problem, where high-value samples play a more important role than those of low-value samples in the model training process. Specifically, the training value of each training sample is assessed according to its predicted probability of ground truth label, and then training samples are resampled to produce a balanced training set, at last the model training is further boosted by using an instance-level value-aware loss function. To conduct fair comparisons among different methods, we compile 13 datasets for imbalanced classification. Experiments demonstrate that our proposed method can effectively measure the training value of training samples, and achieve superior performance in imbalanced classification compared with several existing methods.\",\n \"Title: Hyperbolic Variational Graph Neural Network For Modeling Dynamic Graphs\\nYear: 2021\\n\\nAbstract: Learning representations for graphs plays a critical role in a wide spectrum of downstream applications. In this paper, we summarize the limitations of the prior works in three folds: representation space, modeling dynamics and modeling uncertainty. To bridge this gap, we propose to learn dynamic graph representation in hyperbolic space, for the first time, which aims to infer stochastic node representations. Working with hyperbolic space, we present a novel Hyperbolic Variational Graph Neural Network, referred to as HVGNN. In particular, to model the dynamics, we introduce a Temporal GNN (TGNN) based on a theoretically grounded time encoding approach. To model the uncertainty, we devise a hyperbolic graph variational autoencoder built upon the proposed TGNN to generate stochastic node representations of hyperbolic normal distributions. Furthermore, we introduce a reparameterisable sampling algorithm for the hyperbolic normal distribution to enable the gradient-based learning of HVGNN. Extensive experiments show that HVGNN outperforms state-of-the-art baselines on real-world datasets.\",\n \"Title: Bandwidth-Efficient Precoding in Cell-Free Massive MIMO Networks with Rician Fading Channels\\nYear: 2021\\n\\nAbstract: Global precoding is an effective way to suppress interference in cell-free massive MIMO systems. However, it requires all access points (APs) to upload their local instantaneous channel state information (CSI) to a central processor via capacity-constrained fronthaul links, consuming significant bandwidth resources. Such overhead may become unaffordable in an ultra-dense network (UDN) in future 5G systems, due to the large number of APs and the frequent CSI uploads required to combat the fast-changing state of the high-frequency channels. In order to address this issue, we propose a novel bandwidth-efficient global zero-forcing precoding strategy for downlink transmission in cell-free massive MIMO systems. By exploiting the physical structure of Rician fading channels, we propose a novel model-based CSI compression mechanism, which decomposes a channel matrix into a line-of-sight (LoS) and a non-line-of-sight (NLoS) components, and then compresses them using a model-based method and a singular-value-decomposition (SVD)-based method, respectively. We also present two optimization-based algorithms to obtain the phase information of the LoS component of the channel, which is then used by the proposed channel matrix decomposition. The simulation results demonstrate the efficiency of the proposed precoding strategy on reducing the upload overhead and improving the bandwidth efficiency.\",\n \"Title: A Novel Wide-Baseline Stereo Matching Algorithm Combining Mser And Daisy\\nYear: 2018\\n\\nAbstract: Image(1) matching is a fundamental problem in Computer Vision. In the context of feature-based matching, SIFT (Scale-Invariant Feature Transform) and its variants have long excelled in a wide array of applications. However, for wide-baseline images, it is more challenging due to large perspective distortions. In this paper, we introduce a novel affine invariant feature algorithm combining MSER (Maximum Stable Extreme Region) and DAISY descriptor for wide-baseline scenarios. Firstly, MSER algorithm is used to detect maximum stable extreme regions. Then the MSER region is fit to an elliptical shape. The ellipse area is normalized of direction and shape using the dominant orientation and the length of long and short axes of ellipse, respectively. And square feature region is resampled to a specified radius size. Finally, the DAISY descriptor is used to establish descriptor. The algorithm is validated by using benchmark images and real-world images. We demonstrate that our method has better reliability and is superior to SIFT and MSER+SIFT algorithm in the case of wide-baseline.\",\n \"Title: Tree-like Decision Distillation\\nYear: 2021\\n\\nAbstract: Knowledge distillation pursues a diminutive yet well-behaved student network by harnessing the knowledge learned by a cumbersome teacher model. Prior methods achieve this by making the student imitate shallow behaviors, such as soft targets, features, or attention, of the teacher. In this paper, we argue that what really matters for distillation is the intrinsic problem-solving process captured by the teacher. By dissecting the decision process in a layer-wise manner, we found that the decision-making procedure in the teacher model is conducted in a coarse-to-fine manner, where coarse-grained discrimination (e.g., animal vs vehicle) is attained in early layers, and fine-grained discrimination (e.g., dog vs cat, car vs truck) in latter layers. Motivated by this observation, we propose a new distillation method, dubbed as Tree-like Decision Distillation (TDD), to endow the student with the same problem-solving mechanism as that of the teacher. Extensive experiments demonstrated that TDD yields competitive performance compared to state of the arts. More importantly, it enjoys better interpretability due to its interpretable decision distillation instead of dark knowledge distillation.\",\n \"Title: Examining rice distribution and cropping intensity in a mixed single- and double-cropping region in South China using all available Sentinel 1/2 images\\nYear: 2021\\n\\nAbstract: •Optimize sensors and features for identifying early, middle, and late rice.•Generate 10-m cropping intensity map by integrating Sentinel-1 and -2 images.•Single rice cropping dominates the cropping system in the study area in 2017.\",\n \"Title: Can contrastive learning avoid shortcut solutions?\\nYear: 2021\\n\\nAbstract: The generalization of representations learned via contrastive learning depends crucially on what features of the data are extracted. However, we observe that the contrastive loss does not always sufficiently guide which features are extracted, a behavior that can negatively impact the performance on downstream tasks via “shortcuts\\\", i.e., by inadvertently suppressing important predictive features. We find that feature extraction is influenced by the difficulty of the so-called instance discrimination task (i.e., the task of discriminating pairs of similar points from pairs of dissimilar ones). Although harder pairs improve the representation of some features, the improvement comes at the cost of suppressing previously well represented features. In response, we propose implicit feature modification (IFM), a method for altering positive and negative samples in order to guide contrastive models towards capturing a wider variety of predictive features. Empirically, we observe that IFM reduces feature suppression, and as a result improves performance on vision and medical imaging tasks.\",\n \"Title: Intention-aware Heterogeneous Graph Attention Networks for Fraud Transactions Detection\\nYear: 2021\\n\\nAbstract: ABSTRACTFraud transactions have been the major threats to the healthy development of e-commerce platforms, which not only damage the user experience but also disrupt the orderly operation of the market. User behavioral data is widely used to detect fraud transactions, and recent works show that accurate modeling of user intentions in behavioral sequences can propel further improvements on the performances. However, most existing methods treat each transaction as an independent data instance without considering the transaction-level interactions accessed by transaction attributes, e.g., information on remark, logistics, payment, device and etc., which may fail to achieve satisfactory results in more complex scenarios. In this paper, a novel heterogeneous transaction-intention network is devised to leverage the cross-interaction information over transactions and intentions, which consists of two types of nodes, namely transaction and intention nodes, and two types of edges, i.e., transaction-intention and transaction-transaction edges. Then we propose a graph neural method coined IHGAT(Intention-aware Heterogeneous Graph ATtention networks) that not only perceives sequence-like intentions, but also encodes the relationship among transactions. Extensive experiments on a real-world dataset of Alibaba platform show that our proposed algorithm outperforms state-of-the-art methods in both offline and online modes.\",\n \"Title: PROGRESSIVE MULTI-STAGE FEATURE MIX FOR PERSON RE-IDENTIFICATION\\nYear: 2021\\n\\nAbstract: Image features from a small local region often give strong evidence in person re-identification task. However, CNN suffers from paying too much attention on the most salient local areas, thus ignoring other discriminative clues, e.g., hair, shoes or logos on clothes. In this work, we propose a Progressive Multi-stage feature Mix network (PMM), which enables the model to find out the more precise and diverse features in a progressive manner. Specifically, (i) to enforce the model to look for different clues in the image, we adopt a multi-stage classifier and expect that the model is able to focus on a complementary region in each stage. (ii) we propose an Attentive feature Hard-Mix (A-Hard-Mix) to replace the salient feature blocks by the negative example in the current batch, whose label is different from the current sample. (iii) extensive experiments have been carried out on reID datasets such as the Market-1501, DukeMTMC-reID and CUHK03, showing that the proposed method can boost the re-identification performance significantly. Source code(1) has been released.\",\n \"Title: Deep 3D caricature face generation with identity and structure consistency\\nYear: 2021\\n\\nAbstract: This paper proposed a novel approach to generate face caricatures automatically from a single portrait image. We decompose the process of 3D face caricatures generation into two independent subtasks: appearance transfer of texture and the geometry transfer of mesh. For the appearance transfer, we design a GAN-based network named CariFaceGAN to learn the style mapping from portrait to caricature, in which facial features are leveraged to preserve identity consistency. For geometry transfer, we first learn the transformation of the landmarks between portraits and caricatures in an embedded space obtained with Locally Linear Embedding method, and then Kriging interpolation is used to manipulate the portrait mesh constructed from a single image. The experimental results show that our proposed CariFaceGAN outperforms the state-of-the-art methods in terms of maintaining identity consistency and providing satisfactory visual effects.\",\n \"Title: Self-Attention-Based Real-Time Signal Detector for Communication Systems With Unknown Channel Models\\nYear: 2021\\n\\nAbstract: In this letter, a deep-learning-assisted signal detector is developed for communication systems with unknown channel models. By embedding domain knowledge into a self-attention model, a novel detection unit is devised that enables both reliable estimation and fast training. Furthermore, a sliding-window structure is in combined use with the detection unit to realize real-time signal recovery. We evaluate the performance of the proposed detector using a chemical communication experimental platform, and show the superiority of our design in terms of detection accuracy as well as implementation complexity.\",\n \"Title: Reducing The Influence Of Environmental Factors On Performance Of A Diffusion-Based Personal Exposure Kit\\nYear: 2021\\n\\nAbstract: Sensor technology has enabled the development of portable low-cost monitoring kits that might supplement many applications in conventional monitoring stations. Despite the sensitivity of electrochemical gas sensors to environmental change, they are increasingly important in monitoring polluted microenvironments. The performance of a compact diffusion-based Personal Exposure Kit (PEK) was assessed for real-time gaseous pollutant measurement (CO, O-3, and NO2) under typical environmental conditions encountered in the subtropical city of Hong Kong. A dynamic baseline tracking method and a range of calibration protocols to address system performance were explored under practical scenarios to assess the performance of the PEK in reducing the impact of rapid changes in the ambient environment in personal exposure assessment applications. The results show that the accuracy and stability of the ppb level gas measurement is enhanced even in heterogeneous environments, thus avoiding the need for data post-processing with mathematical algorithms, such as multi-linear regression. This establishes the potential for use in personal exposure monitoring, which has been difficult in the past, and for reporting more accurate and reliable data in real-time to support personal exposure assessment and portable air quality monitoring applications.\",\n \"Title: Inductive and irregular dynamic network representation based on ordinary differential equations\\nYear: 2021\\n\\nAbstract: Dynamic network representation has aroused increasing attention from researchers since it reflects the characteristics of real-world networks and has been widely used in various applications. Enormous efforts have been made to this problem. Existing studies often use fixed-time steps. However, in fact, the dynamics in real-world networks are usually irregular over time. To address this problem, in this paper, we employ ordinary differential equations and propose a novel graph representation approach for dynamic networks, namely Graph-ODE. The core idea lies in that it leverages ordinary differential equations to model the continuous latent dynamics of the network and therefore can naturally capture the evolution pattern. Specifically, to deal with the irregularity of node interactions, we first propose a differential form of GRU aggregator to aggregate the chronological neighbors. In addition, we employ neighbor sampling strategies for efficiency. Besides, our inductive algorithm owns the ability to deal with new emerging nodes. Experimental results on various real-world data sets demonstrate that our method significantly outperforms several state-of-the-art algorithms on downstream tasks.\",\n \"Title: A Quantifiable Stratification Strategy for Tidy-up in Service Robotics\\nYear: 2021\\n\\nAbstract: This paper addresses the problem of tidying up a living room in a messy condition with a service robot (i.e. domestic mobile manipulator). One of the key issues in completing such a task is how to continuously select the object to grasp and take it to the delivery area, especially when the robot works in constrained and partially observable environments. In this paper, we propose a quantifiable st...\",\n \"Title: Disassembling object representations without labels\\nYear: 2021\\n\\nAbstract: •We introduce the disassembling task and an unsupervised approach towards solving it.•UDOR is devised to comply with the modularity of the learned latent representation.•We also introduce two metrics for evaluating the disassembling performance.\",\n \"Title: Bridging the Gap between Label- and Reference-based Synthesis in Multi-attribute Image-to-Image Translation.\\nYear: 2021\\n\\nAbstract: The image-to-image translation (I2IT) model takes a target label or a reference image as the input, and changes a source into the specified target domain. The two types of synthesis, either label- or reference-based, have substantial differences. Particularly, the label-based synthesis reflects the common characteristics of the target domain, and the reference-based shows the specific style similar to the reference. This paper intends to bridge the gap between them in the task of multi-attribute I2IT. We design the label- and reference-based encoding modules (LEM and REM) to compare the domain differences. They first transfer the source image and target label (or reference) into a common embedding space, by providing the opposite directions through the attribute difference vector. Then the two embeddings are simply fused together to form the latent code S_rand (or S_ref), reflecting the domain style differences, which is injected into each layer of the generator by SPADE. To link LEM and REM, so that two types of results benefit each other, we encourage the two latent codes to be close, and set up the cycle consistency between the forward and backward translations on them. Moreover, the interpolation between the S_rand and S_ref is also used to synthesize an extra image. Experiments show that label- and reference-based synthesis are indeed mutually promoted, so that we can have the diverse results from LEM, and high quality results with the similar style of the reference.\",\n \"Title: Introspective Visuomotor Control: Exploiting Uncertainty in Deep Visuomotor Control for Failure Recovery\\nYear: 2021\\n\\nAbstract: End-to-end visuomotor control is emerging as a compelling solution for robot manipulation tasks. However, imitation learning-based visuomotor control approaches tend to suffer from a common limitation, lacking the ability to recover from an out-of-distribution state caused by compounding errors. In this paper, instead of using tactile feedback or explicitly detecting the failure through vision, we...\",\n \"Title: Exploring Pathologist Knowledge for Automatic Assessment of Breast Cancer Metastases in Whole-slide Image\\nYear: 2021\\n\\nAbstract: ABSTRACTAutomatic assessment of breast cancer metastases plays an important role to help pathologist reduce the time-consuming work in histopathological whole-slide image diagnosis. From the utilization of knowledge point of view, the low-magnification level and high-magnification level are carefully checked by the pathologists for tumor pattern and cell tumor characteristic. In this paper, we propose a novel automatic patient-level tumor segmentation and classification method, which makes full use of the diagnosis knowledge clues from pathologists. For tumor segmentation, a multi-level view DeepLabV3+ (MLV-DeepLabV3+) is designed to explore the distinguishing features of cell characteristics between tumor and normal tissue. Furthermore, the expert segmentation models are selected and integrated by Pareto-front optimization to imitate the expert consultation to get perfect diagnosis. For wholeslide classification, multi-level magnifications are adaptive checked to focus on the effective features in different magnification. The experimental results demonstrate that our pathologist knowledge-based automatic assessment of whileslide image is effective and robust on the public benchmark dataset.\",\n \"Title: Attribute-specific Control Units in StyleGAN for Fine-grained Image Manipulation\\nYear: 2021\\n\\nAbstract: ABSTRACTImage manipulation with StyleGAN has been an increasing concern in recent years. Recent works have achieved tremendous success in analyzing several semantic latent spaces to edit the attributes of the generated images. However, due to the limited semantic and spatial manipulation precision in these latent spaces, the existing endeavors are defeated in fine-grained StyleGAN image manipulation, i.e., local attribute translation. To address this issue, we discover attribute-specific control units, which consist of multiple channels of feature maps and modulation styles. Specifically, we collaboratively manipulate the modulation style channels and feature maps in control units rather than individual ones to obtain the semantic and spatial disentangled controls. Furthermore, we propose a simple yet effective method to detect the attribute-specific control units. We move the modulation style along a specific sparse direction vector and replace the filter-wise styles used to compute the feature maps to manipulate these control units. We evaluate our proposed method in various face attribute manipulation tasks. Extensive qualitative and quantitative results demonstrate that our proposed method performs favorably against the state-of-the-art methods. The manipulation results of real images further show the effectiveness of our method.\",\n \"Title: Network-Load Estimation for K-Repetition Grant-Free Access Enabling Adaptive Resource Allocation Towards QoS Enhancement\\nYear: 2021\\n\\nAbstract: In Ultra-Reliable and Low-Latency Communications (URLLC), K-repetition Grant-Free (GF) access can effectively lower the latency by avoiding the complicated handshake procedures. However, it can hardly achieve both high reliability and millimeter-level latency simultaneously if collisions across users frequently happen. In fact, the collision level mainly replies on whether there are sufficient resources for URLLC compared with the network-load, i.e., the number of active users, which, however, is typically not known by the base station (BS). To solve this problem, we propose the effective network-load estimation schemes for URLLC. In particular, based on access states (success, collision, or empty) of resource blocks across consecutive access slots in a subframe, we derive the multi-slot maximum-likelihood (ML) and single-slot least-squares (LS) estimation schemes. Benefitted from the obtained estimation, we further design the adaptive resource allocation scheme for URLLC. Simulation results corroborate that by exploiting the correlation across multiple access slots, our proposal can achieve more accurate estimation than the baseline scheme. Correspondingly, our adaptive resource allocation schedule offers a way to significantly enhance the delay QoS while assuming reliability at only small cost of a slight increment of total access resources.\",\n \"Title: Agent-Based Model On Resilience-Oriented Rapid Responses Of Road Networks Under Seismic Hazard\\nYear: 2021\\n\\nAbstract: This paper explores a new pathway towards seismic resilience of Road Networks (RNs) under earthquake hazards, by leveraging post-shock rapid responses as the key to minimize the functionality losses of RNs, especially in the immediate aftermath of earthquakes. Accordingly, an agent-based modelling (ABM) framework is developed to enable the nuanced examination on resilience of earthquake-damaged RNs, when different system repair approaches are considered. In this framework, those different approaches are predicated on the damage level of individual bridges and on the system recovery timeline, i.e. the response to rehabilitation need is considered as a function of the time elapsed from the event. Each approach is represented by a different agent, whose behaviour is shaped by a set of pre-defined behavioural attributes, while the interplay among those agents is also accounted for, during the entirety of post-shock recovery campaigns. To demonstrate its applicability, the ABM framework is applied to a real-world RN across Luchon, France. As shown by the case-study, post-shock rapid responses are found to be a viable strategy to increase the recovery rate of RNs' functionality in the immediate-, and mid-term aftermath of damaging earthquakes, and ultimately, to improve the seismic resilience thereof.\",\n \"Title: Ciphertext-Only Fault Analysis Of Gift Lightweight Cryptosystem\\nYear: 2022\\n\\nAbstract: Dear editor, The GIFT cryptosystem was proposed by Banik et al.[1]in CHES 2017.It can be widely applied to protect RFID tags and other low-resource devices.It has an SPN struc-ture with a fixed 128-bit key size and two flexible variants of 64-bit and 128-bit block sizes.In simulations,GIFT achieves good performance and surpasses both SIMON and SKINNY[1].In 2013,Fuhr et al.[2]proposed a ciphertext-only fault analysis(CFA)of AES for three types of faults:zero-byte fault,zero-nibble fault,and random-byte fault.Later,Li et al.[3]added new distinguishers(GF,MAP,and GF-SEI)to the LED cryptosystem with high resis-tance to fault injections.Moreover,the CFA in the ran-dom nibble/byte-oriented fault model is more effective and practical.\",\n \"Title: Bootstrapping ViTs: Towards Liberating Vision Transformers from Pre-training\\nYear: 2022\\n\\nAbstract: Recently, vision Transformers (ViTs) are developing rapidly and starting to challenge the domination of con-volutional neural networks (CNNs) in the realm of computer vision (CV). With the general-purpose Transformer architecture replacing the hard-coded inductive biases of convolution, ViTs have surpassed CNNs, especially in data-sufficient circumstances. However, ViTs are prone to over-fit on small datasets and thus rely on large-scale pre-training, which expends enormous time. In this paper, we strive to liberate ViTs from pre-training by introducing CNNs' in- ductive biases back to ViTs while preserving their network architectures for higher upper bound and setting up more suitable optimization objectives. To begin with, an agent CNN is designed based on the given ViT with inductive bi-ases. Then a bootstrapping training algorithm is proposed to jointly optimize the agent and ViT with weight sharing, during which the ViT learns inductive biases from the intermediate features of the agent. Extensive experiments on CIFAR-10/100 and ImageNet-1k with limited training data have shown encouraging results that the inductive biases help ViTs converge significantly faster and outperform conventional CNNs with even fewer parameters. Our code is publicly available at https://github.com/zhfeing/Bootstrapping-ViTs-pytorch.\",\n \"Title: Investigating ADHD subtypes in children using temporal dynamics of the electroencephalogram (EEG) microstates\\nYear: 2021\\n\\nAbstract: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder in children, usually categorized as three predominant subtypes, persistent inattention (ADHD-I), hyperactivity-impulsivity (ADHD-111) and a combination of both (ADHD-C). Identifying reliable features to distinguish different subtypes is significant for clinical individualized treatment. In this work, we conducted a two-stage electroencephalogram (EEG) microstate analysis on 54 healthy controls and 107 ADHD children, including 54 ADHD-Is and 53 ADHD-Cs, aiming to examine the dynamic temporal alterations in ADHDs compared to healthy controls (HCs), as well as different EEG signatures between ADHD subtypes. Results demonstrated that the dynamics of resting-state EEG microstates, particularly centering on salience (state C) and frontal-parietal network (state D), were significantly aberrant in ADHDs. Specifically, the occurrence and coverage of state C were decreased in ADHDs (p=0.002; i0.0015), while the duration and contribution of state D were observably increased (p=0.0016; p=0.0001) compared to HCs. Moreover, the transition probability between state A and C was significantly decreased (p=9.85e-7; p=2.33e-7) in ADHDs, but otherwise increased between state B and D (p=1.02e-7; p=1.07e-6). By contrast, remarkable subtype differences were found primarily on the visual network (state B) between ADHD-Is and ADHD-Cs. Specifically, ADHD-Cs have higher occurrence and coverage of state B than ADHD-Is (p=9.35e-5; p=1.51e-8), suggesting these patients more impulsively aimed to open their eyes when asked to keep eyes closed during the data collection. In summary, this work carefully leveraged EEG temporal dynamics to investigate the aberrant microstate features in ADHDs and provided a new window to look into the subtle differences between ADHD subtypes, which may help to assist precision diagnosis in future.\",\n \"Title: A Self-Supervised Mixed-Curvature Graph Neural Network.\\nYear: 2022\\n\\nAbstract: Graph representation learning received increasing attentions in recent years. Most of the existing methods ignore the complexity of the graph structures and restrict graphs in a single constant-curvature representation space, which is only suitable to particular kinds of graph structure indeed. Additionally, these methods follow the supervised or semi-supervised learning paradigm, and thereby notably limit their deployment on the unlabeled graphs in real applications. To address these aforementioned limitations, we take the first attempt to study the self-supervised graph representation learning in the mixed-curvature spaces. In this paper, we present a novel Self-Supervised Mixed-Curvature Graph Neural Network (SelfMGNN). To capture the complex graph structures, we construct a mixed-curvature space via the Cartesian product of multiple Riemannian component spaces, and design hierarchical attention mechanisms for learning and fusing graph representations across these component spaces. To enable the self-supervised learning, we propose a novel dual contrastive approach. The constructed mixed-curvature space actually provides multiple Riemannian views for the contrastive learning. We introduce a Riemannian projector to reveal these views, and utilize a well-designed Riemannian discriminator for the single-view and cross-view contrastive learning within and across the Riemannian views. Finally, extensive experiments show that SelfMGNN captures the complex graph structures and outperforms state-of-the-art baselines.\",\n \"Title: Robust and Long-term Monocular Teach and Repeat Navigation using a Single-experience Map\\nYear: 2021\\n\\nAbstract: This paper presents a robust monocular visual teach-and-repeat (VT&R) navigation system for long-term operation in outdoor environments. The approach leverages deep-learned descriptors to deal with the high illumination variance of the real world. In particular, a tailored self-supervised descriptor, DarkPoint, is proposed for autonomous navigation in outdoor environments. We seamlessly integrate the localisation with control, in which proportional-integral control is used to eliminate the visual error with the pitfall of the unknown depth. Consequently, our approach achieves day-to-night navigation using a single-experience map and is able to repeat complex and fast manoeuvres. To verify our approach, we performed a vast array of navigation experiments in various outdoor environments, where both navigation accuracy and robustness of the proposed system are investigated. The experimental results show that our approach is superior to the baseline method with regards to accuracy and robustness.\",\n \"Title: Monocular Teach-and-Repeat Navigation using a Deep Steering Network with Scale Estimation\\nYear: 2021\\n\\nAbstract: This paper proposes a novel monocular teach-and-repeat navigation system with the capability of scale awareness, i.e. the absolute distance between observation and goal images. It decomposes the navigation task into a sequence of visual servoing sub-tasks to approach consecutive goal/node images in a topological map. To be specific, a novel hybrid model, named deep steering network is proposed to infer the navigation primitives according to the learned local feature and scale for each visual servoing sub-task. A novel architecture, Scale-Transformer, is developed to estimate the absolute scale between the observation and goal image pair from a set of matched deep representations to assist repeating navigation. The experiments demonstrate that our scale-aware teach-and-repeat method achieves satisfying navigation accuracy, and converges faster than the monocular methods without scale correction given an inaccurate initial pose. The proposed network is integrated into an onboard system deployed on a real robot to achieve real-time navigation in a real environment. A demonstration video can be found online: https://youtu.be/ctlwDaMKnHw\",\n \"Title: A Simple and Robust Spectral Index for Identifying Lodged Maize Using Gaofen1 Satellite Data\\nYear: 2022\\n\\nAbstract: Crop lodging is a major destructive factor for agricultural production. Developing a cost-efficient and accurate method to assess crop lodging is crucial for informing crop management decisions and reducing lodging losses. Satellite remote sensing can provide continuous data on a large scale; however, its utility in detecting lodging crops is limited due to the complexity of lodging events and the unavailability of high spatial and temporal resolution data. Gaofen1 satellite was launched in 2013. The short revisit cycle and wide orbit coverage of the Gaofen1 satellite make it suitable for lodging identification. However, few studies have explored lodging detection using Gaofen1 data, and the operational application of existing approaches over large spatial extents seems to be unrealistic. In this paper, we discuss the identification method of lodged maize and explore the potential of using Gaofen1 data. An analysis of the spectral features after maize lodging revealed that reflectance increased significantly in all bands, compared to non-lodged maize. A spectral sum index was proposed to distinguish lodged and non-lodged maize. Two study areas were considered: Zhaodong City in Heilongjiang Province and Ningjiang District in Jilin Province. The results of the identified lodged maize from the Gaofen1 data were validated based on three methods: first, ground sample points exhibited the overall accuracies of 92.86% and 88.24% for Zhaodong City and Ningjiang District, respectively; second, the cross-comparison differences of 1.01% for Zhaodong City and 1.13% for Ningjiang District were obtained, compared to the results acquired from the finer-resolution Planet data; and third, the identified results from Gaofen1 data and those from farmer survey questionnaires were found to be consistent. The validation results indicate that the proposed index is promising, and the Gaofen1 data have the potential for rapid lodging monitoring.\",\n \"Title: Knowledge Distillation via Constrained Variational Inference.\\nYear: 2022\\n\\nAbstract: Knowledge distillation has been used to capture the knowledge of a teacher model and distill it into a student model with some desirable characteristics such as being smaller, more efficient, or more generalizable. In this paper, we propose a framework for distilling the knowledge of a powerful discriminative model such as a neural network into commonly used graphical models known to be more interpretable (e.g., topic models, autoregressive Hidden Markov Models). Posterior of latent variables in these graphical models (e.g., topic proportions in topic models) is often used as feature representation for predictive tasks. However, these posterior-derived features are known to have poor predictive performance compared to the features learned via purely discriminative approaches. Our framework constrains variational inference for posterior variables in graphical models with a similarity preserving constraint. This constraint distills the knowledge of the discriminative model into the graphical model by ensuring that input pairs with (dis)similar representation in the teacher model also have (dis)similar representation in the student model. By adding this constraint to the variational inference scheme, we guide the graphical model to be a reasonable density model for the data while having predictive features which are as close as possible to those of a discriminative model. To make our framework applicable to a wide range of graphical models, we build upon the Automatic Differentiation Variational Inference (ADVI), a black-box inference framework for graphical models. We demonstrate the effectiveness of our framework on two real-world tasks of disease subtyping and disease trajectory modeling.\",\n \"Title: Style Transformer for Image Inversion and Editing\\nYear: 2022\\n\\nAbstract: Existing GAN inversion methods fail to provide latent codes for reliable reconstruction and flexible editing simultaneously. This paper presents a transformer-based image inversion and editing model for pretrained StyleGAN which is not only with less distortions, but also of high quality and flexibility for editing. The proposed model employs a CNN encoder to provide multi-scale image features as keys and values. Meanwhile it regards the style code to be determined for different layers of the generator as queries. It first initializes query tokens as learnable parameters and maps them into W+ space. Then the multi-stage alternate self-and cross-attention are utilized, updating queries with the purpose of inverting the input by the generator. Moreover, based on the inverted code, we investigate the reference-and label-based attribute editing through a pretrained latent classifier, and achieve flexible image-to-image translation with high quality results. Extensive experiments are carried out, showing better performances on both inversion and editing tasks within StyleGAN. Codes are available at https://github.com/sapphire497/style-transformer.\",\n \"Title: QS-Attn: Query-Selected Attention for Contrastive Learning in I2I Translation\\nYear: 2022\\n\\nAbstract: Unpaired image-to-image (I2I) translation often requires to maximize the mutual information between the source and the translated images across different domains, which is critical for the generator to keep the source content and prevent it from unnecessary modifications. The self-supervised contrastive learning has already been successfully applied in the I2I. By constraining features from the same location to be closer than those from different ones, it implicitly ensures the result to take content from the source. However, previous work uses the features from random locations to impose the constraint, which may not be appropriate since some locations contain less information of source domain. Moreover, the feature itself does not reflect the relation with others. This paper deals with these problems by intentionally selecting significant anchor points for contrastive learning. We design a query-selected attention (QS-Attn) module, which compares feature distances in the source domain, giving an attention matrix with a probability distribution in each row. Then we select queries according to their measurement of significance, computed from the distribution. The selected ones are regarded as anchors for contrastive loss. At the same time, the reduced attention matrix is employed to route features in both domains, so that source relations maintain in the synthesis. We validate our proposed method in three different I2I datasets, showing that it increases the image quality with-out adding learnable parameters. Codes are available at https://github.com/sapphire497/query-selected-attention.\",\n \"Title: DiriE: Knowledge Graph Embedding with Dirichlet Distribution\\nYear: 2022\\n\\nAbstract: ABSTRACT Knowledge graph embedding aims to learn representations of entities and relations in low-dimensional space. Recently, extensive studies combine the characteristics of knowledge graphs with different geometric spaces, including Euclidean space, complex space, hyperbolic space and others, which achieves significant progress in representation learning. However, existing methods are subject to at least one of the following limitations: 1) ignoring the uncertainty, 2) incapability of complex relation patterns. To address the above issues simultaneously, we propose a novel model named DiriE, which embeds entities as Dirichlet distributions and relations as multinomial distributions. DiriE employs Bayesian inference to measure the relations between entities and learns binary embeddings of knowledge graphs for modeling complex relation patterns. Additionally, we propose a two-step negative triple generation method that generates negative triples of both entities and relations. We conduct a solid theoretical analysis to demonstrate the effectiveness and robustness of our method, including the expressiveness of complex relation patterns and the ability to model uncertainty. Furthermore, extensive experiments show that our method outperforms state-of-the-art methods in link prediction on benchmark datasets.\",\n \"Title: Hierarchical Amortized GAN for 3D High Resolution Medical Image Synthesis\\nYear: 2022\\n\\nAbstract: Generative Adversarial Networks (GAN) have many potential medical imaging applications, including data augmentation, domain adaptation, and model explanation. Due to the limited memory of Graphical Processing Units (GPUs), most current 3D GAN models are trained on low-resolution medical images, these models either cannot scale to high-resolution or are prone to patchy artifacts. In this work, we propose a novel end-to-end GAN architecture that can generate high-resolution 3D images. We achieve this goal by using different configurations between training and inference. During training, we adopt a hierarchical structure that simultaneously generates a low-resolution version of the image and a randomly selected sub-volume of the high-resolution image. The hierarchical design has two advantages: First, the memory demand for training on high-resolution images is amortized among sub-volumes. Furthermore, anchoring the high-resolution sub-volumes to a single low-resolution image ensures anatomical consistency between sub-volumes. During inference, our model can directly generate full high-resolution images. We also incorporate an encoder with a similar hierarchical structure into the model to extract features from the images. Experiments on 3D thorax CT and brain MRI demonstrate that our approach outperforms state of the art in image generation. We also demonstrate clinical applications of the proposed model in data augmentation and clinical-relevant feature extraction.\",\n \"Title: Generalized ESO based stable predictive tracking control for micro gas turbine cogeneration system\\nYear: 2022\\n\\nAbstract: •A novel ESO-SPTC combining ESO and SPTC is developed without destroying the overall optimality.•A new discrete-time generalized ESO is proposed to surmount higher-order disturbances.•In SPTC, the infinite horizon inputs fully satisfy the amplitude and rate constraints.•The ESO-SPTC effectively solves the control problem of the micro gas turbine cogeneration system.\",\n \"Title: Rescaling-Assisted Super-Resolution for Medium-Low Resolution Remote Sensing Ship Detection\\nYear: 2022\\n\\nAbstract: Medium-low resolution (M-LR) remote sensing ship detection is a challenging problem due to the small target sizes and insufficient appearance information. Although image super resolution (SR) has become a popular solution in recent years, the ability of image SR is limited since much information is lost in input images. Inspired by the powerful information embedding ability of the encoder in image rescaling, in this paper, we introduce image rescaling to guide the training of image SR. Specifically, we add an adaption module before the SR network, and use the pre-trained rescaling network to guide the optimization of the adaption module. In this way, more information is embedded in the adapted M-LR images, and the subsequent SR module can utilize more information to achieve better performance. Extensive experimental results demonstrate the effectiveness of our method on image SR. More importantly, our method can be used as a pre-processing approach to improve the detection performance.\",\n \"Title: Efficient Superpixel Generation for Polarimetric SAR Images with Cross-Iteration and Hexagonal Initialization\\nYear: 2022\\n\\nAbstract: Clustering-based methods of polarimetric synthetic aperture radar (PolSAR) image superpixel generation are popular due to their feasibility and parameter controllability. However, these methods pay more attention to improving boundary adherence and are usually time-consuming to generate satisfactory superpixels. To address this issue, a novel cross-iteration strategy is proposed to integrate various advantages of different distances with higher computational efficiency for the first time. Therefore, the revised Wishart distance (RWD), which has better boundary adherence but is time-consuming, is first integrated with the geodesic distance (GD), which has higher efficiency and more regular shape, to form a comprehensive similarity measure via the cross-iteration strategy. This similarity measure is then utilized alternately in the local clustering process according to the difference between two consecutive ratios of the current number of unstable pixels to the total number of unstable pixels, to achieve a lower computational burden and competitive accuracy for superpixel generation. Furthermore, hexagonal initialization is adopted to further reduce the complexity of searching pixels for relabelling in the local regions. Extensive experiments conducted on the AIRSAR, RADARSAT-2 and simulated data sets demonstrate that the proposed method exhibits higher computational efficiency and a more regular shape, resulting in a smooth representation of land cover in homogeneous regions and better-preserved details in heterogeneous regions.\",\n \"Title: Climatological Aspects of Active Fires in Northeastern China and Their Relationship to Land Cover\\nYear: 2022\\n\\nAbstract: Biomass burning (BB) is a driving force for heavy haze in northeastern China (NEC) and shows distinct seasonal features. However, little is known about its climatological aspects, which are important for regional BB management and understanding BB effects on climate and environment. Here, the climatological characteristics of active fires and their dependence on land cover in NEC were studied using Moderate Resolution Imaging Spectroradiometer (MODIS) products. Moreover, the influence of meteorological factors on fire activities was explored. The number of fires was found to have increased significantly from 2003 to 2018; and the annual total FRP (FRPtot) showed a generally consistent variation with fire counts. However, the mean fire radiative power for each spot (FRPmean) decreased. Fire activity showed distinctive seasonal variations. Most fires and intense burning events occurred in spring and autumn. Spatially, fires were mainly concentrated in cropland areas in plains, where the frequency of fires increased significantly, especially in spring and autumn. The annual percentage of agricultural fires increased from 34% in 2003 to over 60% after 2008 and the FRPtot of croplands increased from 12% to over 55%. Fires in forests, savannas, and grasslands tended to be associated with higher FRPmean than those in croplands. Analysis indicated that the increasing fire count in NEC is mainly caused by agricultural fires. Although the decreasing FRPmean represents an effective management of BB in recent years, high fire counts and FRPtot in croplands indicate that the crop residue burning cannot be simply banned and a need instead for effective applications. More efforts should be made on clean utilization of straw. The accumulation of dry biomass, high temperature, and low humidity, and weak precipitation are conducive to the fire activities. This study provides a comprehensive analysis of BB in NEC and provides a reference for regional BB management and control.\",\n \"Title: Cross Attention Based Style Distribution for Controllable Person Image Synthesis.\\nYear: 2022\\n\\nAbstract: Controllable person image synthesis task enables a wide range of applications through explicit control over body pose and appearance. In this paper, we propose a cross attention based style distribution module that computes between the source semantic styles and target pose for pose transfer. The module intentionally selects the style represented by each semantic and distributes them according to the target pose. The attention matrix in cross attention expresses the dynamic similarities between the target pose and the source styles for all semantics. Therefore, it can be utilized to route the color and texture from the source image, and is further constrained by the target parsing map to achieve a clearer objective. At the same time, to encode the source appearance accurately, the self attention among different semantic styles is also added. The effectiveness of our model is validated quantitatively and qualitatively on pose transfer and virtual try-on tasks. Codes are available at https://github.com/xyzhouo/CASD.\",\n \"Title: User Behavior Pre-training for Online Fraud Detection\\nYear: 2022\\n\\nAbstract: The outbreak of COVID-19 burgeons newborn services on online platforms and simultaneously buoys multifarious online fraud activities. Due to the rapid technological and commercial innovation that opens up an ever-expanding set of products, the insufficient labeling data renders existing supervised or semi-supervised fraud detection models ineffective in these emerging services. However, the ever accumulated user behavioral data on online platforms might be helpful in improving the performance of fraud detection on newborn services. To this end, in this paper, we propose to pre-train user behavior sequences, which consist of orderly arranged actions, from the large-scale unlabeled data sources for online fraud detection. Recent studies illustrate accurate extraction of user intentions~(formed by consecutive actions) in behavioral sequences can propel improvements in the performance of online fraud detection. By anatomizing the characteristic of online fraud activities, we devise a model named UB-PTM that learns knowledge of fraud activities by three agent tasks at different granularities, i.e., action, intention, and sequence levels, from large-scale unlabeled data. Extensive experiments on three downstream transaction and user-level online fraud detection tasks demonstrate that our UB-PTM is able to outperform the state-of-the-art designing for specific tasks.\",\n \"Title: A Self-supervised Riemannian GNN with Time Varying Curvature for Temporal Graph Learning\\nYear: 2022\\n\\nAbstract: ABSTRACTRepresentation learning on temporal graphs has drawn considerable research attention owing to its fundamental importance in a wide spectrum of real-world applications. Though a number of studies succeed in obtaining time-dependent representations, it still faces significant challenges. On the one hand, most of the existing methods restrict the embedding space with a certain curvature. However, the underlying geometry in fact shifts among the positive curvature hyperspherical, zero curvature Euclidean and negative curvature hyperbolic spaces in the evolvement over time. On the other hand, these methods usually require abundant labels to learn temporal representations, and thereby notably limit their wide use in the unlabeled graphs of the real applications. To bridge this gap, we make the first attempt to study the problem of self-supervised temporal graph representation learning in the general Riemannian space, supporting the time-varying curvature to shift among hyperspherical, Euclidean and hyperbolic spaces. In this paper, we present a novel self-supervised Riemannian graph neural network (SelfℛGNN). Specifically, we design a curvature-varying Riemannian GNN with a theoretically grounded time encoding, and formulate a functional curvature over time to model the evolvement shifting among the positive, zero and negative curvature spaces. To enable the self-supervised learning, we propose a novel reweighting self-contrastive approach, exploring the Riemannian space itself without augmentation, and propose an edge-based self-supervised curvature learning with the Ricci curvature. Extensive experiments show the superiority of SelfRGNN, and moreover, the case study shows the time-varying curvature of temporal graph in reality.\",\n \"Title: Explore the Correlation between Environmental Factors and the Spatial Distribution of Property Crime\\nYear: 2022\\n\\nAbstract: Comprehensively understanding the factors influencing crime is a prerequisite for preventing and combating crime. Although some studies have investigated the relationship between environmental factors and property crime, the interaction between factors was not fully considered in these studies, and the explanation of complex factors may be insufficient. This paper explored the influence of environmental factors on property crime using factor regression and factor interaction based on data from the central city of Lanzhou, China. Our findings showed that: (1) The distribution of crime cases showed the pattern of a local multi-center. Shop density, hotel density, entertainment density and house price were the four dominant environmental drivers of property crime; (2) The relationship between the light intensity and property crime had different correlation explanations in temporal projection and spatial projection. There was a normal distribution curve between the number of property crimes and the Price-to-Earnings Ratio (PE Ratio) of the community house price; and (3) The results of the factor interaction indicated that the effect of all factors on crime showed a two-factor enhancement. As an important catalyst, shop density had the strongest interaction with other factors. Shop density gradient influenced the degree of interpretation of spatial heterogeneity of property crime.\",\n \"Title: Transmit Antenna Placement Based on Graph Theory for MIMO Radar Detection\\nYear: 2022\\n\\nAbstract: Optimal antenna placement for target detection using multiple-input multiple-output (MIMO) radar system with widely separated antennas is studied in this paper. Considering the problem of placing a limited number of transmit antennas in a given space to maximize the detection performance, an optimization problem is formulated with the output signal-to-noise ratio (SNR) indicator as the performance metric. The initial problem is a nonlinear integer programming problem, and with the increase of the number of antennas, the computational complexity using traditional methods can be huge. In this paper, we discretize the feasible space into several grid points and employ graph theory to handle the problem. The antennas and grid points can be viewed as vertices in a bipartite graph, so that the antenna placement problem can be viewed as seeking for a proper matching between two vertex sets. We transform the problem into a stable matching (SM) problem and a maximum weighted matching (MWM) problem respectively, and propose Gale-Shapley (GS)-based and Kuhn-Munkres (KM)-based algorithms to deal with them with polynomial complexity. Numerical examples are provided to evaluate the effectiveness of the proposed methods.\",\n \"Title: Robust Tuning of Active Disturbance Rejection Controller for Time-Delay Systems With Application to a Factual Electrostatic Precipitator\\nYear: 2022\\n\\nAbstract: Active disturbance rejection control (ADRC) shows great potential in mitigating various uncertainties of both motion and process control. However, the controller tuning is generally time-consuming, and the resulting performance highly depends on the individual experience. This brief aims to develop a standard robust tuning rule for a time-delayed ADRC structure based on a class of time-delay systems represented by a second-order plus time delay (SOPTD) model. The bandwidth parameters of the controller and the observer are, respectively, scaled in terms of SOPTD parameters. The resulting dimensionless parameters enable exhaustive evaluation of the robustness. Compared to the traditional metrics, it reveals that delay margin is the dominant robustness index for the controller tuning. A dominated form of the robust tuning rule is recommended, and the stability condition of a closed-loop system is given. Simulations and experiments are conducted on a factual electrostatic precipitator in the coal-fired power plant to validate the efficacy of the proposed tuning rule.\",\n \"Title: Stability Analysis and Performance Improvement of Power Sharing Control in Islanded Microgrids\\nYear: 2022\\n\\nAbstract: Due to the requirement of synchronism and power sharing, droop control and its variations have become one essential component for distributed generator (DG)-powered microgrids. However, the power sharing accuracy and system stability margin may be threatened by the randomness from the load demand and renewable generation. In this paper, a dynamic stability analysis is first performed on a DG-powered microgrid through a produced system frequency response model (SFR). The results point out that (i) the critical system eigenvalues directly vary with the system operating condition; (ii) a fixed-gain power sharing control is prone to be less damped and loses stability easily under some operating conditions. Then, the heuristic adaptive dynamic programming (HDP) strategy is used for power sharing control with the benefit of adapting to real-time disturbances and uncertainties. Through Lyapunov theorem, stability analysis is provided to demonstrate the reliability of the HDP-based power sharing control in islanded microgrids. Finally, simulation tests verify the analysis results and demonstrate the favorable performance of the HDP-based power sharing control under uncertain load disturbances.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":200,"string":"200"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13347,"string":"13,347"}}},{"rowIdx":13348,"cells":{"question_id":{"kind":"string","value":"Meixia Tao"},"question":{"kind":"string","value":"Generate an abstract for the title \"Guest Editorial Caching for Communication Systems and Networks - Part II.\" using the following items: IEEE, Caching, Communication, Networks, Memory."},"answer":{"kind":"string","value":"Welcome to the second part of the IEEE JSAC special issue on Caching for Communication Systems and Networks. The goal of this special issue is to present the multiple facets of caching, from information theory to networking and services, and explore the role of memory in communications. This is a very timely topic due to recent technological and theoretical advances summarized in the tutorial pape..."},"correct_answer":{"kind":"string","value":"Welcome to the second part of the IEEE JSAC special issue on Caching for Communication Systems and Networks. The goal of this special issue is to present the multiple facets of caching, from information theory to networking and services, and explore the role of memory in communications. This is a very timely topic due to recent technological and theoretical advances summarized in the tutorial pape..."},"documents":{"kind":"list like","value":["Title: Cross-Layer Optimization of Two-Way Relaying for Statistical QoS Guarantees\nYear: 2012\n\nAbstract: Two-way relaying promises considerable improvements on spectral efficiency in wireless relay networks. While most existing works focus on physical layer approaches to exploit its capacity gain, the benefits of two-way relaying on upper layers are much less investigated. In this paper, we study the cross-layer design and optimization for delay quality-of-service (QoS) provisioning in two-way relay systems. Our goal is to find the optimal transmission policy to maximize the weighted sum throughput of the two users in the physical layer while guaranteeing the individual statistical delay-QoS requirement for each user in the datalink layer. This statistical delay-QoS requirement is characterized by the QoS exponent. By integrating the concept of effective capacity, the cross-layer optimization problem is equivalent to a weighted sum effective capacity maximization problem. We derive the jointly optimal power and rate adaptation policies for both three-phase and two-phase two-way relay protocols. Numerical results show that the proposed adaptive transmission policies can efficiently provide QoS guarantees and improve the performance. In addition, the throughput gain obtained by the considered three-phase and two-phase protocols over direct transmission is significant when the delay-QoS requirements are loose, but the gain diminishes at tight delay requirements. It is also found that, in the two-phase protocol, the relay node should be placed closer to the source with more stringent delay requirement.","Title: Efficient interference mitigating strategies for two-way relay channels.\nYear: 2011\n\nAbstract: Hierarchical wireless networks have the potential to provide the needed capacity to a large number of mobile stations (MSs). According to this system architecture, the MSs are served by a dense network of fixed relay nodes (RNs) fed by a small number of large hub base stations (HBSs). In such deployment, high spectral efficiencies can be achieved if the RNs act as two-way relays; however this gives rise to co-channel interference (CCI) which needs to be mitigated. In order to gain insights on the impact of CCI to this scenario we consider an HBS with two highly directional antennas communicating with two MSs via two interfering two-way RNs. We investigate the average maximum sum-rate of two cooperative strategies. The first is based on Decode-and-Forward (DF) and network coding and acts as a baseline. The second strategy is based on Amplify-and-Forward (AF) and Network MIMO processing over both the backhaul and access channels. Furthermore we devise some cooperative protocols that utilize two, three or four time slots. It is shown that the 2-slot schemes perform generally better and that the DF strategy achieves superior performance when CCI is low while AF with Network MIMO is superior when CCI is high. © 2011 IEEE.","Title: Generalized signal alignment for arbitrary MIMO two-way relay channels\nYear: 2014\n\nAbstract: In this paper, we study the achievable degrees of freedom (DoF) for an arbitrary MIMO two-way relay channel, where there are K source nodes, each equipped with Mi antennas, for i = 1, 2, ⋯, K, and one relay node, equipped with N antennas. Each source node can exchange independent messages with an arbitrary set of other source nodes assisted by the relay. We extend our newly-proposed transmission scheme, generalized signal alignment (GSA) in [1], to the arbitrary MIMO two-way relay channel with antenna configuration satisfying N ≥ Mi + Mj, ∀i ≠ j. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a projected subspace at the relay. This is realized by jointly designing the precoding matrices at all source nodes and the processing matrix at the relay node. Moreover, the aligned subspaces are orthogonal to each other. Applying the GSA, we show that the DoF upper bound min {Σi=1K Mi, 2 Σi=2K Mi, 2N} is tight under the antenna configuration N ≥ max{Σi=1K Mi-Ms-Mt+ds, t | ∀s, t}. Here, ds, t denotes the DoF of the message exchanged between nodes s and t. In the special case when the arbitrary MIMO two-way relay channel reduces to the K-user MIMO Y channel, we show that our achievable region of DoF upper bound with GSA is larger than the existing result.","Title: Robust Beamforming for Wireless Information and Power Transmission\nYear: 2012\n\nAbstract: In this letter, we study the robust beamforming problem for the multi-antenna wireless broadcasting system with simultaneous information and power transmission, under the assumption of imperfect channel state information (CSI) at the transmitter. Following the worst-case deterministic model, our objective is to maximize the worst-case harvested energy for the energy receiver while guaranteeing that the rate for the information receiver is above a threshold for all possible channel realizations. Such problem is nonconvex with infinite number of constraints. Using certain transformation techniques, we convert this problem into a relaxed semidefinite programming problem (SDP) which can be solved efficiently. We further show that the solution of the relaxed SDP problem is always rank-one. This indicates that the relaxation is tight and we can get the optimal solution for the original problem. Simulation results are presented to validate the effectiveness of the proposed algorithm.","Title: Nonlinear Precoding Design for MIMO Amplify-and-Forward Two-Way Relay Systems.\nYear: 2012\n\nAbstract: In traditional multiple-input-multiple-output (MIMO) channel and MIMO one-way relay system, nonlinear precoding design has shown significant performance gain over linear design. In this paper, we aim to study nonlinear precoding design for MIMO amplify-and-forward (AF) two-way relay systems, where nonlinear minimal mean square error (MMSE) decision feedback equalizers (DFEs) are used in two destinations, and linear transmit precoding is applied at the source and relay nodes. We first investigate nonlinear precoding design, where the precoding is only conducted at two sources for a fixed-relay precoder. After some transformations, we prove that this design problem is convex, and an efficient algorithm is provided to find the optimal solution. Then, we consider the nonlinear joint precoding design to further incorporate relay precoding. Due to the nonconvexity of this problem, we first propose an iterative algorithm (Algorithm I) to approach the optimal solution. It is proven that Algorithm I is convergent and can converge to a stationary point of the joint design problem. Moreover, we present a simplified iterative algorithm (Algorithm II) for joint precoding design to reduce the design complexity. It is found that Algorithm II almost achieves the same performance as Algorithm I in most cases. Our simulation results show that the proposed nonlinear joint precoding design significantly outperforms the linear joint precoding design. It is also shown that the choice between the proposed nonlinear source precoding design and the linear relay precoding design is dependent on specific conditions. © 1967-2012 IEEE.","Title: MIMO Two-Way Compress-and-Forward Relaying with Approximate Joint Eigen-Decomposition\nYear: 2013\n\nAbstract: While compress-and-forward (CF) is one of the basic relay protocols in cooperative transmission, little is known about the optimal design of CF in multiple-input multiple-output (MIMO) two-way relay channels (TWRC). An intuitive method is to compress each element of the superimposed signal vector during the multiple-access (MAC) phase independently and with identical compression noise variance. In this paper, we introduce an improved compression method. The key idea is to apply approximate joint diagonalization (AJD) to realize simultaneous eigen-decomposition of the two channel matrices in the MAC phase of two-way relaying in an approximate manner. After that, a novel covariance matrix design of the compression noise vector is derived for sum-rate maximization. Numerical results show that the proposed CF design can improve the spectral efficiency, especially when the relay node is close to any of the two source nodes instead of in the midpoint.","Title: Iteratively Decoded Variable Length Space-Time Coded Modulation: Code Construction and Convergence Analysis\nYear: 2007\n\nAbstract: An iteratively decoded variable length space time coded modulation (VL-STCM-ID) scheme capable of simultaneously providing both coding and iteration gain as well as multiplexing and diversity gain is proposed. Non-binary unity-rate precoders are employed for assisting the iterative decoding of the VL-STCM-ID scheme. The discrete-valued source symbols are first encoded into variable-length codewords that are mapped to the spatial and temporal domains. Then the variable-length codewords are interleaved and fed to the precoder assisted modulator. More explicitly, the proposed VL-STCM-ID arrangement is a jointly designed iteratively decoded scheme combining source coding, channel coding, modulation as well as spatial diversity/multiplexing. As expected, the higher the source correlation, the higher the achievable performance gain of the scheme becomes. Furthermore, the performance of the VL-STCM-ID scheme is about 14.6 dB better than that of the fixed length STCM (FL-STCM) benchmarker at a source symbol error ratio of 10-4","Title: Resource Allocation with Subcarrier Pairing in OFDMA Two-Way Relay Networks.\nYear: 2012\n\nAbstract: This study considers an orthogonal frequency-division multiple-access (OFDMA)-based multi-user two-way relay network where multiple mobile stations (MSs) communicate with a common base station (BS) via multiple relay stations (RSs). We study the joint optimization problem of subcarrier-pairing based relay-power allocation, relay selection, and subcarrier assignment. The problem is formulated as a mixed integer programming problem. By using the dual method, we propose an efficient algorithm to solve the problem in an asymptotically optimal manner. Simulation results show that the proposed method can improve system performance significantly over the conventional methods. © 2012 IEEE.","Title: Diagonal block space-time code design for diversity and coding advantage over flat fading channels\nYear: 2004\n\nAbstract: The potential promised by multiple transmit antennas has raised considerable interest in space-time coding for wireless communications. In this paper, we propose a systematic approach for designing space-time trellis codes over flat fading channels with full antenna diversity and good coding advantage. It is suitable for an arbitrary number of transmit antennas with arbitrary signal constellations. The key to this approach is to separate the traditional space-time trellis code design into two parts. It first encodes the information symbols using a one-dimensional (M,1) nonbinary block code, with M being the number of transmit antennas, and then transmits the coded symbols diagonally across the space-time grid. We show that regardless of channel time-selectivity, this new class of space-time codes always achieves a transmit diversity of order M with a minimum number of trellis states and a coding advantage equal to the minimum product distance of the employed block code. Traditional delay diversity codes can be viewed as a special case of this coding scheme in which the repetition block code is employed. To maximize the coding advantage, we introduce an optimal construction of the nonbinary block code for a given modulation scheme. In particular, an efficient suboptimal solution for multilevel phase-shift-keying (PSK) modulation is proposed. Some code examples with 2-6 bits/s/Hz and two to six transmit antennas are provided, and they demonstrate excellent performance via computer simulations. Although it is proposed for flat fading channels, this coding scheme can be easily extended to frequency-selective fading channels.","Title: A New SLNR-Based Linear Precoding for Downlink Multi-User Multi-Stream MIMO Systems\nYear: 2010\n\nAbstract: Signal-to-leakage-and-noise ratio (SLNR) is a promising criterion for linear precoder design in multi-user (MU) multiple-input multiple-output (MIMO) systems. It decouples the precoder design problem and makes closed-form solution available. In this letter, we present a new linear precoding scheme by slightly relaxing the SLNR maximization for MU-MIMO systems with multiple data streams per user. The precoding matrices are obtained by a general form of simultaneous diagonalization of two Hermitian matrices. The new scheme reduces the gap between the per-stream effective channel gains, an inherent limitation in the original SLNR precoding scheme. Simulation results demonstrate that the proposed precoding achieves considerable gains in error performance over the original one for multi-stream transmission while maintaining almost the same achievable sum-rate.","Title: Competitive scheduling for OFDMA systems with guaranteed transmission rate\nYear: 2009\n\nAbstract: Next-generation broadband wireless standards use orthogonal frequency division multiple access (OFDMA) as the preferred physical layer multiple access scheme, especially for the downlink. Due to limited resources available at the base station, multi-user resource allocation is crucial for delivering the applications with various quality-of-service (QoS) demands. We study the OFDMA resource allocation problem for the adaptive modulation and coding (AMC) mode of mobile WiMAX, in which resources in the form of allocation units (AU) are to be allocated and the channel knowledge of only some good sub-channels for the users is available to the scheduler. The objective is to maximize the sum-rate for all the users while maintaining guaranteed minimum and maximum traffic rates for certain users under a total transmission power constraint. Two novel factors, band selectivity factor (BSF) and competition factor (CF), are introduced. Based on the two factors, we propose a sub-optimal approach, rate-guaranteed competitive scheduling (RCS). It is suitable to be deployed in practical systems and exploits multi-user diversity with very low complexity. Simulation results show that RCS can achieve almost 75% of throughput of the optimal solution.","Title: Precoding design for cognitive two-way relay networks.\nYear: 2012\n\nAbstract: We study precoding design for cognitive two-way relay networks (C-TWRNs). In C-TWRN, the multi-antenna secondary transmitter not only transmits its own signal to the secondary receiver, it also acts as relay to help forwarding signals of two primary users via two-way relaying in the licensed frequency band. Our objective is to design linear relay transceiver or precoder such that the achievable rate of the secondary user is maximized while maintaining rate requirements of the primary users. To achieve this goal, different relay strategies, i.e., amplify-and-forward (AF), bit level XOR based decode-and-forward (DF-XOR) and symbol level superposition coding based decode-and-forward (DF-SUP), are considered. By transforming these non-convex design problems into suitable forms, efficient optimization tools are used to find the optimal solutions of all the schemes. Closed-form solutions are also obtained under certain conditions.","Title: Joint Source and Relay Optimization for Non-Regenerative MIMO Two-Way Relay Systems with Imperfect CSI.\nYear: 2012\n\nAbstract: In this paper, we consider a non-regenerative MIMO two-way relay system with imperfect channel state information (CSI). We employ a stochastic approach to model the channel uncertainties and address the robust joint source and relay optimization problem based on the minimum mean squared error (MMSE) criterion. With imperfect CSI, the self-interference (SI) cannot be completely canceled at destinat...","Title: A Transmission Scheme for Continuous ARQ Protocols over Underwater Acoustic Channels\nYear: 2009\n\nAbstract: Due to the half-duplex property of the underwater acoustic channels, the classic stop-and-wait ARQ (SW-ARQ) and its variants are generally thought to be the only class of ARQ protocols that can be applied in underwater. When combined with the large propagation delay property of the underwater acoustic channels, the use of SW-ARQ and its variants makes the throughput performance of underwater acoustic communication systems very inefficient. In this paper, we propose a transmission scheme that takes advantage of the long propagation delay in underwater to enable the use of continuous ARQ protocols over underwater acoustic channels. Simulation results show that our proposed transmission scheme allows much higher throughput to be achieved than both the classic SW-ARQ and its variants, even when simple continuous ARQ protocols are used.","Title: QoS-Aware Transmission Policies for OFDM Bidirectional Decode-and-Forward Relaying\nYear: 2013\n\nAbstract: Two-way relaying can considerably improve spectral efficiency in relay-assisted bidirectional communications. However, the benefits and flexible structure of orthogonal frequency division multiplexing (OFDM)-based two-way relay systems is much less exploited. Moreover, most of existing works have not considered quality-of-service (QoS) provisioning for two-way relaying. In this paper, we consider ...","Title: On the Maximum Achievable Sum-Rate of Interfering Two-Way Relay Channels.\nYear: 2012\n\nAbstract: Hierarchical networks can provide very high data rates to multiple mobile stations (MSs) through a dense network of fixed relay nodes (RNs) fed by few hub base stations (HBSs). In order to achieve high spectral efficiencies RNs can act as two-way RNs. However the dense RN deployment gives rise to high co-channel interference (CCI) that limits sum-rate performance. In this letter we consider a simple hierarchical network consisting of an HBS with two highly directional antennas communicating with two MSs via two interfering two-way RNs. To mitigate CCI and boost sum-rates we propose a two-way relaying strategy based on AF combined with Network MIMO processing which is applied over the concatenation of the backhaul and access network channels. We compare our proposed strategy with a baseline DF approach and we show that it performs significantly better when CCI is dominant. © 2006 IEEE.","Title: Impact of imperfect channel state information on ARQ schemes over rayleigh fading channels\nYear: 2009\n\nAbstract: With imperfect channel state information (CSI) acquired by channel estimation at the receiver, the performances of automatic-repeat-request (ARQ) systems are evaluated as a function of the accuracy of channel estimation. A link between network-layer performances and physical-layer parameters is therefore established. We study in particular the goodput and the accepted packet error rate as a function of the channel estimation mean square error (MSE) and the factors which affect the MSE. The results enable us to analyze the optimum allocation of energy for data transmission and energy for pilot channel estimation so as to maximize the goodput.","Title: Content-aware transmission with delay threshold in heterogeneous networks\nYear: 2013\n\nAbstract: With the popularity of smart devices, content based internet services are growing rapidly. Different from real-time services, the end-to-end delay requirements of the contents are much less stringent. In this paper, we consider the delay-tolerant content-aware delivery in two-tier heterogeneous wireless networks. Taking transmit power consumption into account, we propose a new transmission framework by pushing users from macrocells to small cells at the cost of tolerable delay. We model the tolerable delay of content delivery in a stochastic way by considering users' interests. In this model, we adopt a progressively decreasing interest function which treats the delay as its argument. A modified Black-Scholes model is adopted to model the interest function. Thus, there exists a tradeoff between users' experience and power consumption. We consider power efficiency under a certain level of quality of experience (QoE) to handle this tradeoff. A content-aware transmission scheme with the optimal power efficiency is proposed. Simulation results show that under the maximal power efficiency criterion, about 18% of power consumption is reduced while about 90% of users' interests is preserved.","Title: Optimal Channel and Relay Assignment in OFDM-Based Multi-Relay Multi-Pair Two-Way Communication Networks\nYear: 2012\n\nAbstract: Efficient utilization of radio resources in wireless networks is crucial and has been investigated extensively. This letter considers a wireless relay network where multiple user pairs conduct bidirectional communications via multiple relays based on orthogonal frequency-division multiplexing (OFDM) transmission. The joint optimization of channel and relay assignment, including subcarrier pairing, subcarrier allocation as well as relay selection, for total throughput maximization is formulated as a combinatorial optimization problem. Using a graph theoretical approach, we solve the problem optimally in polynomial time by transforming it into a maximum weighted bipartite matching (MWBM) problem. Simulation studies are carried out to evaluate the network total throughput versus transmit power per node and the number of relay nodes.","Title: Spectrum Leasing and Cooperative Resource Allocation in Cognitive OFDMA Networks\nYear: 2012\n\nAbstract: This paper considers a cooperative orthogonal frequency division multiple access (OFDMA)-based cognitive radio network where the primary system leases some of its subchannels to the secondary system for a fraction of time in exchange for the secondary users (SUs) assisting the transmission of primary users (PUs) as relays. Our aim is to determine the cooperation strategies among the primary and secondary systems so as to maximize the sum-rate of SUs while maintaining quality-of-service (QoS) requirements of PUs. We formulate a joint optimization problem of PU transmission mode selection, SU (or relay) selection, subcarrier assignment, power control, and time allocation. By applying dual method, this mixed integer programming problem is decomposed into parallel per-subcarrier subproblems, with each determining the cooperation strategy between one PU and one SU. We show that, on each leased subcarrier, the optimal strategy is to let a SU exclusively act as a relay or transmit for itself. This result is fundamentally different from the conventional spectrum leasing in single-channel systems where a SU must transmit a fraction of time for itself if it helps the PU's transmission. We then propose a subgradient-based algorithm to find the asymptotically optimal solution to the primal problem in polynomial time. Simulation results demonstrate that the proposed algorithm can significantly enhance the network performance.","Title: Game Theoretic Multimode Precoding Strategy Selection for MIMO Multiple Access Channels\nYear: 2010\n\nAbstract: This paper is concerned with decentralized selection of multimode precoding strategy for multiple-input multiple-output (MIMO) multiple access channels. We formulate it as a discrete noncooperative game. This game is shown to possess at least one pure strategy Nash equilibrium (NE) and the optimal strategy profile which maximizes the sum rate constitutes a pure strategy NE. Then we propose a decentralized algorithm based on learning automata to achieve the NE. A repeated mechanism is introduced to improve the sum rate performance and a mechanism for adapting step size is designed to control the convergence speed. Simulation results show that the proposed algorithm, which only requires limited feedback, can achieve near optimal or optimal sum rate performance.","Title: Sparse channel estimation for OFDM transmission over two-way works\nYear: 2012\n\nAbstract: Compressed sensing (CS) has recently emerged as a powerful signal acquisition paradigm. CS enables the recovery of high-dimensional sparse signals from much fewer samples than usually required. Further, quite a few recent channel measurement experiments show that many wireless channels also tend to exhibit sparsity. In this case, CS theory can be applicable to sparse channel estimation and its effectiveness has been validated in point-to-point (P2P) communication. In this work, we study sparse channel estimation for two-way relay networks (TWRN). Unlike P2P systems, applying CS theory to sparse channel estimation in TWRN is much more challenging. One issue is that the equivalent channels (terminal-relay-terminal) may be no longer sparse due to the linear convolutional operation. On this basis, novel schemes are proposed to solve this problem and effectively improve the accuracy of TWRN channel estimation when using CS theory. Extensive numerical results are provided to corroborate the proposed studies.","Title: Coordinated Multicast Beamforming in Multicell Networks.\nYear: 2012\n\nAbstract: We study physical layer multicasting in multicell networks where each base station, equipped with multiple antennas, transmits a common message using a single beamformer to multiple users in the same cell. We investigate two coordinated beamforming designs: the quality-of-service (QoS) beamforming and the max-min SINR (signal-to-interference-plus-noise ratio) beamforming. The goal of the QoS beamf...","Title: Channel Estimation for OFDM Systems over Doubly Selective Channels: A Distributed Compressive Sensing Based Approach.\nYear: 2013\n\nAbstract: Channel estimation for an orthogonal frequency-division multiplexing (OFDM) broadband system over a doubly selective channel is very challenging. This is mainly due to the significant Doppler shift, which results in a time-frequency doubly-selective (DS) channel. The DS channel features a large number of channel coefficients, which introduces inter-carrier interference (ICI) and forces the need for allocating a large number of pilot subcarriers. To tackle this problem, in this paper we propose a novel channel estimation scheme based on distributed compressive sensing (DCS) theory. Taking advantage of the basis expansion model (BEM) and the channel sparsity in the delay domain, we transform the original DS channel into a novel two-dimensional channel model, where several jointly sparse BEM coefficient vectors become the estimation goal. Then a special decoupling form originating from a novel sparse pilot pattern is designed for such estimation, which results in an ICI-free structure and enables the DCS application to make joint estimation of these vectors accurately. Combined with a smoothing treatment process, the proposed scheme can achieve significantly higher estimation accuracy than the existing ones, although with a much smaller number of pilot subcarriers. Theoretical analysis and simulation results both confirm its performance merits. © 2013 IEEE.","Title: Linear Precoding Designs for Amplify-and-Forward Multiuser Two-Way Relay Systems\nYear: 2012\n\nAbstract: Two-way relaying can improve spectral efficiency in two-user cooperative communications. It also has great potential in multiuser systems. A major problem of designing a multiuser two-way relay system (MU-TWRS) is transceiver or precoding design to suppress co-channel interference. This paper aims to study linear precoding designs for a cellular MU-TWRS where a multi-antenna base station (BS) conducts bi-directional communications with multiple mobile stations (MSs) via a multi-antenna relay station (RS) with amplify-and-forward relay strategy. The design goal is to optimize uplink performance, including total mean-square error (Total-MSE) and sum rate, while maintaining individual signal-to-interference-plus-noise ratio (SINR) requirement for downlink signals. We show that the BS precoding design with the RS precoder fixed can be converted to a standard second order cone programming (SOCP) and the optimal solution is obtained efficiently. The RS precoding design with the BS precoder fixed, on the other hand, is non-convex and we present an iterative algorithm to find a local optimal solution. Then, the joint BS-RS precoding is obtained by solving the BS precoding and the RS precoding alternately. Comprehensive simulation is conducted to demonstrate the effectiveness of the proposed precoding designs.","Title: Analysis of Differential Unitary Space-Time Modulation over Non-Identical MIMO Channels\nYear: 2008\n\nAbstract: We present an analytical study on the error performance of differential unitary space-time modulation (DUSTM) over multiple-input multiple-output (MIMO) channels with non- identical fading statistics. The channel for each transmit-receive antenna pair is assumed to be independent, non-identically distributed (i.n.i.d), and time-varying Rayleigh fading. We first show that the maximum-likelihood (ML) differential detector of DUSTM over such channels is involved except for differential cyclic group codes. Applying the distribution of quadratic forms of Gaussian vectors, we derive closed-form expressions for the exact error probabilities of two specific unitary classes, namely, cyclic group codes and orthogonal codes. Simple and useful asymptotic bounds are also obtained. Our analysis leads to several general findings.","Title: Superimposed XOR: a new physical layer network coding scheme for two-way relay channels\nYear: 2009\n\nAbstract: We present a new physical layer network coding (PLNC) scheme, called superimposed XOR, for two-way relay channels. The new scheme specifically takes into account the channel as well as information asymmetry in the broadcast phase of two-way relaying. It is based upon both bitwise XOR and symbol-level superposition coding. We first derive its achievable rate regions when integrated with two known time control protocols over Gaussian channels. We then demonstrate its average maximum sum-rate and service delay performance over fading channels. Compared with the existing bitwise XOR and symbol-level superposition coding, the proposed superimposed XOR scheme achieves larger rate region in asymmetric channels. As a result, it performs much better in terms of averaged maximum sum-rate and service delay over fading channels. Numerical results also show that the proposed practical PLNC closely approaches the capacity bound given by the information-theoretic random binning.","Title: Optimization framework and graph-based approach for relay-assisted bidirectional OFDMA cellular networks\nYear: 2010\n\nAbstract: This paper considers a relay-assisted bidirectional cellular network where the base station (BS) communicates with each mobile station (MS) using orthogonal frequency-division multiple-access (OFDMA) for both uplink and downlink. The goal is to improve the overall system performance by exploring the full potential of the network in various dimensions including user, subcarrier, relay, and bidirectional traffic. In this work, we first introduce a novel three-time-slot time-division duplexing (TDD) transmission protocol. This protocol unifies direct transmission, one-way relaying and network-coded two-way relaying between the BS and each MS. Using the proposed three-time-slot TDD protocol, we then propose an optimization framework for resource allocation to achieve the following gains: cooperative diversity (via relay selection), network coding gain (via bidirectional transmission mode selection), and multiuser diversity (via subcarrier assignment). We formulate the problem as a combinatorial optimization problem, which is NP-complete. To make it more tractable, we adopt a graph-based approach. We first establish the equivalence between the original problem and a maximum weighted clique problem (MWCP) in graph theory. A metaheuristic algorithm based on ant colony optimization (ACO) is then employed to find the solution in polynomial time. Simulation results demonstrate that the proposed protocol together with the ACO algorithm significantly enhances the system total throughput.","Title: Outage Probability and Finite-SNR Diversity–Multiplexing Tradeoff for Two-Way Relay Fading Channels\nYear: 2013\n\nAbstract: In this paper, we analyze the outage probability and finite-SNR diversity-multiplexing tradeoff (f-DMT) performance for two-way relay channels (TWRCs). Both amplify-and-forward (AF) and decode-and-forward (DF) relay protocols are considered. The two source nodes are equipped with single antenna, and the relay is equipped with single or multiple antennas. First, we derive lower bounds of outage probability for single- and multiantenna relay AF, upper and lower bounds for multiantenna relay DF, and the exact closed-form expression for single-antenna DF. These results are suitable for arbitrary time-sharing and rate allocation for DF and arbitrary rate allocation for AF. Numerical results show that the derived lower bounds approximate very well the actual outage performance obtained by Monte Carlo simulation. Based on the tight lower bounds, we further derive estimates of the f-DMTs. We find that AF always outperforms DF in terms of f-DMT in all SNR regimes. However, the comparison result of outage performance between AF and DF depends on channel conditions. Finally, we also discuss the impact of relay location, time-sharing, and rate allocation on the outage and f-DMT via numerical examples.","Title: Secure Beamforming for MIMO Two-Way Communications With an Untrusted Relay\nYear: 2014\n\nAbstract: This paper studies the secure beamforming design in a multiple-antenna three-node system where two source nodes exchange messages with the help of an untrusted relay node. The relay acts as both an essential signal forwarder and a potential eavesdropper. Both two-phase and three-phase two-way relay strategies are considered. Our goal is to jointly optimize the source and relay beamformers for maximizing the secrecy sum rate of the two-way communications. We first derive the optimal relay beamformer structures. Then, iterative algorithms are proposed to find source and relay beamformers jointly based on alternating optimization. Furthermore, we conduct asymptotic analysis on the maximum secrecy sum-rate. Our analysis shows that when all transmit powers approach infinity, the two-phase two-way relay scheme achieves the maximum secrecy sum rate if the source beamformers are designed such that the received signals at the relay align in the same direction. This reveals an important advantage of signal alignment technique in against eavesdropping. It is also shown that if the source powers approach zero, the three-phase scheme performs the best while the two-phase scheme is even worse than direct transmission. Simulation results have verified the efficiency of the proposed secure beamforming algorithms as well as the analytical findings.","Title: Utility-Based Wireless Resource Allocation for Variable Rate Transmission\nYear: 2007\n\nAbstract: For most wireless services with variable rate transmission, both average rate and rate oscillation are important performance metrics. The traditional performance criterion, utility of average transmission rate, boosts the average rate but also results in high rate oscillations. We introduce a utility function of instantaneous transmission rates. It is capable of facilitating the resource allocation with flexible combinations of average rate and rate oscillation. Based on the new utility, we consider the time and power allocation in a time-shared wireless network. Two adaptation policies are developed, namely, time sharing (TS) and joint time sharing and power control (JTPC). An extension to quantized time sharing with limited channel feedback (QTSL) for practical systems is also discussed. Simulation results show that by controlling the concavity of the utility function, a tradeoff between the average rate and rate oscillation can be easily made.","Title: Graph-Based Optimization for Relay-Assisted Bidirectional Cellular Networks\nYear: 2010\n\nAbstract: This paper considers a relay-assisted bidirectional cellular network where the base station (BS) communicates with each mobile station (MS) using orthogonal frequency-division multiple-access (OFDMA) for both uplink and downlink. We first introduce a novel three-time-slot time-division duplexing (TDD) transmission protocol. This protocol unifies the direct transmission, one-way relaying and network-coded two-way relaying between the BS and each MS. Using the proposed TDD protocol, we then propose an optimization framework for resource allocation to achieve the following gains: cooperative diversity gain (via relay selection), network coding gain (via bidirectional transmission mode selection), and multiuser diversity gain (via subcarrier assignment). We formulate the problem as an integer programming problem. By establishing its equivalence with a maximum weighted clique problem (MWCP) in graph theory, we show that the problem can be solved using an ant colony optimization (ACO) based metaheuristic algorithm in polynomial time. Simulation results demonstrate that the proposed protocol together with the ACO algorithm significantly enhances the system total throughput compared with conventional schemes.","Title: Cross-layer resource allocation of two-way relaying for statistical delay-QoS guarantees\nYear: 2012\n\nAbstract: In this paper, we consider the cross-layer design for delay quality-of-service (QoS) provisioning in two-way relay systems. We aim to find the optimal resource allocation policy to maximize the weighted sum-rate while guaranteeing the statistical delay-QoS requirements for both users. The delay requirement is characterized as the QoS exponent. With the integration of the concept of effective capacity, the cross-layer optimization problem is equivalent to a weighted sum effective capacity maximization problem. We derive the optimal joint power and rate adaptation policy for the two-phase two-way relaying. Numerical results show that the proposed policy can efficiently support diverse QoS requirements and significantly improve the performance compared with both the fixed power scheme and the weight-based method.","Title: Finite-SNR Diversity-Multiplexing Tradeoff for Two-Way Relay Fading Channel\nYear: 2010\n\nAbstract: This paper studies the performance limits of two-way relay channel (TWRC) at finite signal-to-noise ratio (SNR) in Rayleigh fading environment. A two-phase decode-and-forward (DF) protocol is considered. We first derive closed-form expressions for both outage probability and diversity-multiplexing tradeoff (DMT). Our results are general and suitable for any time sharing and any rate allocation in the two-way relay protocol. It is found that DF outperforms amplify-and-forward (AF) when either multiplexing gain or SNR is small enough, otherwise, DF is inferior to AF in term of outage probability. Meanwhile, finite-SNR DMT of DF is always lower than that of AF regardless of SNR due to the additional sum-rate constraint imposed on the relay node for full decoding. Furthermore, the optimum relay location for any given combination of time sharing and rate allocation is presented.","Title: Degrees of Freedom for MIMO Two-Way X Relay Channel\nYear: 2013\n\nAbstract: We study the degrees of freedom (DOF) of a multiple-input multiple-output (MIMO) two-way X relay channel, where there are two groups of source nodes and one relay node, each equipped with multiple antennas, and each of the two source nodes in one group exchanges independent messages with the two source nodes in the other group via the relay node. It is assumed that every source node is equipped with $M$ antennas while the relay is equipped with $N$ antennas. We first show that the upper bound on the total DOF for this network is $2\\min\\{2M, N\\}$ and then focus on the case of $N\\leq 2M$ so that the DOF is upper bounded by twice the number of antennas at the relay. By applying signal alignment for network coding and joint transceiver design for interference cancellation, we show that this upper bound can be achieved when $N\\leq\\lfloor{8M\\over 5}\\rfloor$. We also show that with signal alignment only but no joint transceiver design, the upper bound is achievable when $N\\leq\\lfloor{4M\\over 3}\\rfloor$. Simulation results are provided to corroborate the theoretical results and to demonstrate the performance of the proposed scheme in the finite signal-to-noise ratio regime.","Title: Pseudo Exclusive-OR for LDPC Coded Two-Way Relay Block Fading Channels.\nYear: 2011\n\nAbstract: We present a novel adaptive physical layer network coding (PLNC) at the relay, called pseudo exclusive-or (PXOR), for LDPC coded two-way relay (TWR) block fading channels. Based on the pairwise check decoding (PCD), the check relationship table generated by the proposed PXOR mapping obtains the same Hamming distances of the PLNC mapped codewords as that of conventional XOR mapping. In the meantime, the PXOR mapping optimizes the Euclidean distances by adjusting the symbol distances dynamically as far as possible in order to compensate the amplitude fading and phase deviation of the TWR block fading channels. For the system end-to-end error probability, simulation results show that the proposed coded PXOR considerably outperforms the coded conventional XOR and achieves the same performance as the complicated coded CNC for considered two TWR block fading channels. © 2011 IEEE.","Title: Linear Precoding for Multi-Pair Two-Way MIMO Relay Systems With Max-Min Fairness\nYear: 2012\n\nAbstract: Two-way relaying has demonstrated significant gain in spectral efficiency by applying network coding when a pair of source nodes exchange information via a relay node. This paper is concerned with the scenario where multiple pairs of users exchange information through a common relay node equipped with multiple antennas. We aim to design linear precoding at the relay based on amplify-and-forward strategy. The goal is to maximize the minimum achievable rate among all the users subject to a peak relay power constraint so as to achieve the max-min fairness. We first convert this nonconvex problem into a series of semidefinite programming problems using bisection search and certain transformation techniques. A quasi-optimal solution is then obtained by using semidefinite relaxation (SDR). To reduce the design complexity, we further introduce a pair-wise zero-forcing (ZF) structure that eliminates the interference among different user pairs. By applying this structure, the precoding design problem is simplified to a power allocation problem which can be optimally solved. A simplified power allocation algorithm is also proposed. Simulation results show that the proposed SDR-based precoding not only achieves high minimum user rate but also maintains good sum-rate performance when compared with existing schemes. It is also shown that the proposed pair-wise ZF precoding with simplified power allocation strikes a good balance between performance and complexity.","Title: A hybrid relay selection scheme using differential modulation\nYear: 2009\n\nAbstract: In this paper, we propose a hybrid relay selection (HRS) scheme in a general cooperative network using differential modulation. In the HRS scheme, when the destination decodes successfully, the relay nodes will remain silent. Otherwise, optimal relay node has to be determined to make an additional transmission. In this process, all the relays are divided into two groups, referred to as an amplify-and-forward (AAF) relay group and a decode-and-forward (DAF) relay group depending on whether they can decode correctly or not. The relay, which has the maximum signal-to-noise ratio (SNR) at the destination, will be selected from both AAF and DAF relay groups. Simulation results show that the proposed relay selection scheme significantly outperforms the conventional AAF selection in terms of both frame error rate (FER) and throughput, and these performance gains considerably grow as the number of relay nodes increases.","Title: Generalized signal alignment for MIMO two-way X relay channels\nYear: 2014\n\nAbstract: We study the degrees of freedom (DoF) of MIMO two-way X relay channels. Previous work studied the case N <; 2M, where N and M denote the number of antennas at the relay and each source, respectively, and showed that the maximum DoF of 2N is achievable when N <; ⌊8M/5⌋ by applying signal alignment (SA) for network coding and interference cancelation. This work considers the case N > 2M where the performance is limited by the number of antennas at each source node and conventional SA is not feasible. We propose a generalized signal alignment (GSA) based transmission scheme. The key is to let the signals to be exchanged between every source node align in a transformed subspace, rather than the direct subspace, at the relay so as to form network-coded signals. This is realized by jointly designing the precoding matrices at all source nodes and the processing matrix at the relay. Moreover, the aligned subspaces are orthogonal to each other. By applying the GSA, we show that the DoF upper bound 4M is achievable when M ≤ ⌊ 2N/5 ⌋ (M is even) or M ≤ ⌊ 2N-1 /5 ⌋ (M is odd). Numerical results also demonstrate that our proposed transmission scheme is feasible and effective.","Title: Generalized layered space-time codes for high data rate wireless communications\nYear: 2004\n\nAbstract: We present the architecture of generalized layered space-time codes (GLST) as a combination of Bell Labs layered space-time (BLAST) architecture and space-time coding (STC) in multiple-antenna wireless communication systems. This approach provides both spectral and power efficiency with moderate complexity. The framework is to partition all the available transmit antennas into groups and apply STC on each group as component codes. Based on the mappings from coded symbols to transmit antenna groups, we can construct different GLST systems. Particularly, horizontal mapping and diagonal mapping are introduced and referred to as HGLST and DGLST respectively. The basic decoding of GLST, under quasi-static flat Rayleigh fading environments and assuming perfectly known channel state information (CSI) at the receiver, combines group interference suppression and group interference cancellation techniques. As a result, the individual STC on each group is decoded serially. To improve the overall system performance, we derive the optimal power allocation among all space-time codewords without requiring the knowledge of CSI at the transmitter and suitable for all GLST systems. We also derive the optimal serial decoding order based on the channel realizations at the receiver for HGLST systems without power allocation. Simulation results show that both can provide much improvement. To further enhance the system performance, we propose a low complexity hard-decision iterative decoding method. This method efficiently exploits full receive antenna diversity and, hence, dramatically improves the system performance which is confirmed by simulation.","Title: Distributed cross-layer resource allocation for statistical QoS provisioning in femtocell networks\nYear: 2013\n\nAbstract: In this paper, we study the cross layer design and optimization for delay quality-of-service (QoS) provisioning in spectrum sharing femtocell networks. Our goal is to find the optimal resource allocation policy to maximize the throughput for each femtocell user, addressing the co-channel interference problem in the physical layer and the individual statistical delay-QoS guarantee problem from the upper layers. The statistical delay-QoS requirement is characterized by the QoS exponent. By integrating the concept of effective capacity, the cross-layer optimization problem is formulated as an effective capacity maximization game. With partial dual decomposition, this game is solved through a hierarchical structure. Specifically, we derive the optimal power allocation policy for femtocell users and design a distributed algorithm to obtain the Nash Equilibrium (N.E.). Numerical results show that the proposed policy can efficiently improve the performance of the networks.","Title: Joint subchannel and power allocation in interference-limited OFDMA femtocells with heterogeneous QoS guarantee\nYear: 2012\n\nAbstract: In this paper, we consider the joint subchannel and power allocation problem in both the uplink and the downlink for two-tier networks comprising spectrum-sharing macrocells and femtocells. A joint subchannel and power allocation scheme for co-channel femtocells is proposed, aiming to maximize the capacity for delay-tolerant users subject to delay-sensitive users' quality of service and interference constraints imposed by macrocells. The joint subchannel and power allocation problem is modeled as an mixed integer programming problem, then transformed into a convex optimization problem by relaxing subchannel sharing, and finally solved by a dual decomposition approach. The effectiveness of the proposed approach is verified by simulations and compared with existing scheme.","Title: Auction-Based Optimal Power Allocation in Multiuser Cooperative Networks.\nYear: 2011\n\nAbstract: Cooperative Caching can be an effective mechanism for reducing electronic content provisioning cost in Social Wireless Networks (SWNETs) which are formed by a collection of mobile data enabled phones physically gathering in settings such as university campus, malls, airport and other public places. In this paper, we first propose an optimal collaborative object caching policy in order to minimize the object provision cost in SWNETs with homogenous user requests and a peer-rebate model for promoting collaboration. Then using an analytical model we study the impacts of user selfishness on the provisioning cost and the earned rebate when certain nodes in an SWNET selfishly deviate from the optimal policy in order to increase their individually earned rebate. The analytical model is extensively validated by experimental results from simulated SWNETs using the network simulator ns2.","Title: Finite-SNR Diversity-Multiplexing Tradeoff for Two-Way Multi-Antenna Relay Fading Channels\nYear: 2010\n\nAbstract: In this paper, we study the diversity-multiplexing tradeoff (DMT) of two-way relay channels (TWRC) with multi-antenna relay at finite signal-to-noise ratio (SNR). A two-phase decode-and-forward (DF) relay protocol and Rayleigh fading environment are considered. We first derive upper and lower bounds on the outage probability. These bounds are very tight for all practical SNR regions. Based on these bounds, the estimates of finite-SNR DMT (f-DMT) are then obtained. Our analysis shows that the multiplexing gain approaches one when SNR decreases to zero. On the other hand, the diversity gain approaches the number of relay antennas when SNR increases to infinity. Furthermore, the impact of time sharing, rate allocation and relay location on the outage and f-DMT is also discussed through numerical examples.","Title: High rate trellis coded differential unitary space-time modulation via super unitarity\nYear: 2006\n\nAbstract: We introduce a new trellis coded differential unitary space-time modulation scheme for multiple-antenna wireless systems. In the new scheme, the constellation expansion is executed using a super unitarity technique so that the number of available unitary matrices is increased but the transmitted symbol alphabet is kept the same. A novel set partitioning strategy is then applied to the expanded matrix set. This scheme avoids the rate-loss problem suffered by traditional code design. We provide some examples using the proposed code construction method. Compared with existing ones, the new codes can not only achieve lower transmitter and receiver complexity, but also provide higher coding gains","Title: Secure beamforming for MIMO two-way transmission with an untrusted relay\nYear: 2013\n\nAbstract: From security perspective, a friendly relay may help to keep the confidential messages from being eavesdropped, while an untrusted relay may intentionally eavesdrop the messages when relaying. This paper studies the secure beamforming for multiple-input multiple-output (MIMO) two-way communications, where two source nodes exchange information with the help of an untrusted relay node. The relay adopts amplify-and-forward (AF) strategy and acts as both an essential helper and a potential eavesdropper. Our goal is to maximize the secrecy sum rate of the bidirectional links by jointly optimizing the source and relay beamformers. For the two-phase two-way relay scheme, we first derive the optimal structure of the relay beamformer and then propose an iterative algorithm to jointly optimize the source and relay beamformers. Then, a comprehensive study on the asymptotical performance is conducted by letting the source and relay powers approach zero or infinity. In particular, we show that when all powers approach infinity, the two-way relay scheme achieves the maximum secrecy rate if the transceiver beamformers are designed such that the received signals at the relay can be aligned to be parallel.","Title: Cooperative jamming for secrecy in decentralized wireless networks\nYear: 2012\n\nAbstract: Cooperative jamming as a physical layer security enhancement has recently drawn considerable attention. While most existing works focus on communication systems with a small number of nodes, we investigate the use of cooperative jamming for providing secrecy in large-scale decentralized networks consisting of randomly distributed legitimate users and eavesdroppers. A modified slotted ALOHA protocol, named CJ-ALOHA, is considered where each legitimate transmitter either sends its message signal or acts as a helping jammer according to a message transmission probability p. We derive the secrecy transmission capacity to characterize the network throughput and show how the throughput is affected by the CJ-ALOHA protocol. Both analytical and numerical insights are provided on the design of the CJ-ALOHA protocol for optimal throughput performance.","Title: A Network Flow Approach to Throughput Maximization in Cooperative OFDMA Networks.\nYear: 2013\n\nAbstract: In wireless cooperative orthogonal frequency-division multiple-access (OFDMA) networks, it is important to adapt the transmission strategies for each user according to the network channel dynamics in order to optimize the overall system performance. The adaption involves transmission mode selection (a user can choose from direct or cooperative transmission), subcarrier assignment, subcarrier pairing (the incoming and outgoing subcarriers at the relay for cooperative transmission need to be matched), relay selection, as well as power allocation and hence is highly challenging. Many previous works only consider a subset of the adaptation. In this paper, we tackle the joint optimization problem using a network flow approach. Specifically, we first show that for given power allocation, the combinatorial optimization problem of transmission mode selection, subcarrier assignment, relay selection and subcarrier pairing for the system total throughput maximization can be transformed into a minimum cost network flow (MCNF) problem with integer solutions. The linear optimal distribution (LOD) algorithm is applied to find the optimal solution in polynomial time. We then solve the mixed integer programming problem of the joint assignment and power allocation in an asymptotically optimal way in the dual domain. Simulation results show that the proposed algorithms can significantly enhance the overall system throughput. © 2002-2012 IEEE.","Title: Power Efficiency for Device-to-Device Communications.\nYear: 2013\n\nAbstract: The concept of device-to-Device (D2D) communication as an underlay coexistence with cellular networks gains many advantages of improving system performance. In this paper, we model such a two-layer heterogenous network based on stochastic geometry approach. We aim at minimizing the expected power consumption of the D2D layer while satisfying the outage performance of both D2D layer and cellular layer. We consider two kinds of power control schemes. The first one is referred as to independent power control where the transmit powers are statistically independent of the networks and all channel conditions. The second is named as dependent power control where the transmit power of each user is dependent on its own channel condition. A closed-form expression of optimal independent power control is derived, and we point out that the optimal power control for this case is fixed and not relevant to the randomness of the network. For the dependent power control case, we propose an efficient way to find the close-to-optimal solution for the power-efficiency optimization problem. Numerical results show that dependent power control scheme saves about half of power that the independent power control scheme demands.","Title: An optimal graph approach for optimizing OFDMA relay networks\nYear: 2012\n\nAbstract: This paper considers a relay-assisted cooperative network where multiple relays assist the communication of multiple users using orthogonal frequency-division multiple-access (OFDMA). Our goal is to improve system performance by exploring full potential of the network in various dimensions, including user, relay, channel, and transmission mode. We formulate the joint optimization of subcarrier pairing, subcarrier assignment, relay selection, and transmission mode selection. We show that this combinatorial optimization problem can be transformed into a minimum cost network flow (MCNF) problem with integer solutions in graph theory. Then the linear optimal distribution (LOD) algorithm is applied to find the optimal solution in polynomial time. Simulations show that the proposed algorithm can significantly enhance the overall system throughput.","Title: Optimal power allocation scheme on generalized layered space-time coding systems.\nYear: 2001\n\nAbstract: We consider a generalized layered Space-Time(GLST) architecture with parallel Space-Time (ST) codes andderive an optimal power allocation (PA) scheme over the Space-Time encoders to minimize the overall frame error rate. Weprove that the optimal power allocation scheme will equate thederivatives of the frame error rate functions of all the ST codes.From simulation, we show that the derived optimal powerallocation has a 1-2 dB gain over equal power scheme. Also, theproposed scheme has a...","Title: Design an asynchronous radio interferometric positioning system using dual-tone signaling\nYear: 2013\n\nAbstract: Radio interferometric positioning systems (RIPS) are recently proposed for low-complexity and high-accuracy localization. However, the original RIPS involves four nodes (two transmitters and two receivers) for a ranging session, and requires stringent time synchronization upon two receivers. In this paper, an asynchronous radio interferometric positioning system (ARIPS) is developed with larger positioning ranges. In ARIPS, two anchors (nodes with known positions) transmit two slightly different dual-tone signals. The differences of the two dual-tone signals create two low-frequency differential signals at the target receiver. The phase differences of the differential signals bear the time-difference-of-arrival (TDOA) information, i.e., the distance information. We develop two new methods to estimate the TDOA with and without accurate knowledge of the frequencies of the differential signals, respectively. By switching the pairs of the anchor nodes, several TDOAs can be obtained and thus the location of the target node can be estimated. The proposed ARIPS is robust to carrier frequency offsets (CFOs) and random phases due to asynchronous oscillators, and increases the resolving range limit due to the well-known integer ambiguity issue. Simulation results illustrate the performance of the proposed ARIPS.","Title: Hash function mapping design utilizing probability distribution for pre-image resistance\nYear: 2012\n\nAbstract: Hash functions are often used to protect the integrity of information. In general, the design of hash functions should satisfy three standards: pre-image resistance, second pre-image resistance and collision resistance. The design of hash functions in the literature assumes that the messages to be transmitted are equally probable. In this paper, we focus on the pre-image resistance and investigate the problem of mapping design for hash function utilizing the unequal occurrence probabilities of the messages. We first present a necessary condition for the optimal mapping and then introduce a heuristic algorithm. Simulation experiments are carried out to evaluate the performance of the proposed new design. It is shown that the probability of successful attack can be significantly reduced compared with the conventional design. Our algorithm can be useful in scenarios where the attacker has limited ability or time to estimate the probability distribution of the messages. To our best knowledge, this work is the first attempt of making use of the message distribution in designing hash functions for information security.","Title: Joint Source and Relay Precoding Designs for MIMO Two-Way Relay Systems\nYear: 2011\n\nAbstract: We investigate the source and relay precoding based on the minimum mean-square-error (MMSE) criterion for amplify-and-forward (AF) MIMO two-way relay systems. This joint design problem is shown to be a highly nonconvex optimization problem. In this work, we present two efficient design algorithms. The first one aims to minimize the total MSE of two users by alternatively solving three trackable sub-problems and it is iterative in nature. Since the optimal solution for each sub-problem can be obtained, the convergence is thus ensured. The second design aims to compromise computational complexity and system performance and possesses a certain precoder structure. This structure is able to parallelize channels in the Multiple Access (MAC) and Broadcast (BC) phases of the two-way relaying. Based on such structure, the joint precoding design is simply reduced to the joint source and relay power allocation problem. The efficiency of both proposed algorithms is verified through simulation.","Title: Alternative Awaiting and Broadcast for Two-Way Relay Fading Channels\nYear: 2011\n\nAbstract: We investigate a two-way relay (TWR) fading channel where two source nodes wish to exchange information with the help of a relay node. Given traditional TWR protocols, transmission rates in both directions are known to be limited by the hop with lower capacity, i.e., the min operations between uplink and downlink. In this paper, we propose a new transmission protocol, called alternative awaiting and broadcast (AAB), to cancel the min operations in the TWR fading channels. The operational principles, a new upper bound on ergodic sum capacity (ESC), and a convergence behavior of the average delay of signal transmission (ST) (in the relay buffer) for the proposed AAB protocol are analyzed. Moreover, we propose a suboptimal encoding/decoding solution for the AAB protocol and derive an achievable ergodic sum rate (ESR) with a corresponding average delay of ST. Numerical results show that 1) the proposed AAB protocol significantly improves the achievable ESR compared with the traditional TWR protocols, and 2) considering the average delay of system service (SS) (in the source buffer), the average delay of ST induced by the proposed AAB protocol is very small and negligible.","Title: Non-Cooperative Power Control for Faded Wireless Ad Hoc Networks\nYear: 2007\n\nAbstract: The problem of non-cooperative power control is studied for wireless ad hoc networks supporting data services. We develop a maximum throughput based non-cooperative power control game (MT-NPG), where each transmitter node requires only the effective interference measurement from its corresponding receiver. An expression for the optimal power control to maximize the average transmission rate for each individual link is derived. Then, we design a distributed iterative power updating algorithm to approximate the optimal solution. The existence and uniqueness of Nash equilibrium for the proposed game is investigated. Simulation results show that the proposed MT-NPG yields a significant improvement in the sum of average achievable rates when compared with existing approaches.","Title: Blind Spectrum Sensing by Information Theoretic Criteria\nYear: 2010\n\nAbstract: Information theoretic criteria (ITC) based spectrum sensing is a promising blind method which can reliably detect the primary users while requiring little prior information in cognitive radio networks. In this paper, we provide an intensive treatment on the ITC sensing. We first introduce a new over-determined channel model constructed by applying multiple antennas in order to make the ITC applicable. Then, a simplified ITC sensing algorithm is introduced, which needs to compute and compare only two decision values. Compared with the original ITC (OITC) sensing algorithm, the simplified algorithm significantly reduces the computational complexity without losing any performance. Furthermore, applying the recent advances in random matrix theory, we derive closed-form expressions to tightly approximate both the probability of false alarm and probability of detection. Finally, comprehensive simulations are carried out to evaluate the performance of the proposed ITC sensing algorithms. Results show that they considerably outperform existing blind spectrum sensing methods in certain cases.","Title: Effects of non-identical rayleigh fading on differential unitary space-time modulation\nYear: 2007\n\nAbstract: Non-identical fading distribution in a multiple-input multiple-output (MIMO) channel, including unequal average channel gains and fade rates, often occurs when antennas are not co-located. In this paper, we present an analytical study of the effects of non-identical Rayleigh fading on the error performance of differential unitary space-time modulation (DUSTM). The fading processes for different transmit-receive antenna pairs are assumed to be independent and time-variant. We find that the maximum-likelihood (ML) differential detector of DUSTM over such channels is involved except for differential cyclic group codes. The conventional detector is proved to be asymptotically optimal in the limit of high signal-to-noise ratio (SNR) over static fading channels. Applying the distribution of quadratic forms of Gaussian vectors, we then derive closed-form expressions for the exact error probabilities of two specific unitary classes, namely, cyclic group codes and orthogonal codes. Simple and useful asymptotic bounds on error probabilities are also obtained. Our analysis leads to the following general findings: (1) equal power allocation is asymptotically optimal, and (2) non-identical channel gain distribution degrades the error performance. Finally, we also introduce a water-filling based power allocation to exploit the transmit non-identical fading statistics.","Title: Adaptive Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems\nYear: 2006\n\nAbstract: Most existing work on adaptive allocation of subcarriers and power in multiuser OFDM systems has focused on homogeneous traffic consisting of delay-constrained data (guaranteed service) or delay-tolerant data (best-effort service) only. In this work, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and no-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the DC traffic under a total transmission power constraint. Finding the optimal allocation of subcarriers and power is formulated as a convex programming problem. An iterative algorithm is proposed to compute the optimal solutions numerically. A low-complexity suboptimal allocation algorithm is also presented. Simulation experiments are conducted to evaluate the performance of the proposed algorithms in terms of service outage probability and achievable transmission rate pairs for DC and NDC traffic.","Title: Trellis-Coded Differential Unitary Space-Time Modulation In Slow Flat Fading Channels With Interleaver\nYear: 2002\n\nAbstract: This paper considers trellis-coded differential unitary space-time modulation for multiple-antenna systems when neither the transmitter nor the receiver has access to channel state information. The channel is assumed to be slowly time-varying flat Rayleigh fading with ideal interleaver. We derive the metric for maximum likelihood differential decoding and the Chernoff bound for pair-wise error probability. We show that performance is dominated by the minimum Hamming distance which contributes linearly to the order of diversity. Code construction is described for rate m/(m + 1) trellis codes. Several code examples are provided based on diagonal cyclic group constellations for two transmit antennas with data rate 1 and 2 bits/s/Hz. Simulation results show that the proposed trellis-coded differential scheme can achieve high data rate communications by medium signal-to-noise ratio without channel estimation.","Title: Exploiting hop diversity with frequency sharing in multi-hop OFDM networks\nYear: 2009\n\nAbstract: We present a framework of frequency sharing in multi-hop OFDM networks. It enables simultaneous transmission of multiple hops without causing inter-hop interference. Hop diversity can then be achieved by exploiting channel frequency selectivity across active hops. Under the framework, we formulate a joint optimization problem of sub-channel assignment, power allocation, and time control. The proposed scheme is shown to achieve significantly higher spectral efficiency than hop-by-hop transmission. It also avoids the interference limiting issue incurred in full spatial reuse schemes.","Title: Rotating Decode-and-Forward for Two Pairs of Two-Way Communications\nYear: 2010\n\nAbstract: We study the transmission strategy for a system consisting of two pairs of two-way communication links. The information exchange between the two nodes in each pair can only occur with the help of the nodes in the other pair. A novel transmission protocol, named Rotating Decode-and-Forward (RDF) is proposed. In this protocol, the two pairs take turns to forward the signal for each other while having their own information embedded in the signal-to-forward by applying physical layer network coding. The achievable rate region of this protocol is derived. Numerical examples show that proposed RDF protocol can provide significantly higher spectral efficiency than conventional protocols where the transmissions of information signal and signal-to-forward are carried out separately.","Title: Joint Source and Relay Precoding Designs for MIMO Two-Way Relaying Based on MSE Criterion\nYear: 2011\n\nAbstract: Properly designed precoders can significantly improve the spectral efficiency of multiple-input multiple-output (MIMO) relay systems. In this paper, we investigate joint source and relay precoding design based on the mean-square-error (MSE) criterion in MIMO two-way relay systems, where two multiantenna source nodes exchange information via a multiantenna amplify-and-forward relay node. This problem is non-convex and its optimal solution remains unsolved. Aiming to find an efficient way to solve the problem, we first decouple the primal problem into three tractable subproblems, and then propose an iterative precoding design algorithm based on alternating optimization. The solution to each subproblem is optimal and unique, thus the convergence of the iterative algorithm is guaranteed. Second, we propose a structured precoding design to lower the computational complexity. The proposed precoding structure is able to parallelize the channels in the multiple access (MAC) phase and broadcast (BC) phase. It thus reduces the precoding design to a simple power allocation problem. Last, for the special case where only a single data stream is transmitted from each source node, we present a source-antenna-selection (SAS)-based precoding design algorithm. This algorithm selects only one antenna for transmission from each source and thus requires lower signalling overhead. Comprehensive simulation is conducted to evaluate the effectiveness of all the proposed precoding designs.","Title: Power and Subcarrier Allocation for Physical-Layer Security in OFDMA Networks\nYear: 2011\n\nAbstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink OFDMA-based broadband network with coexistence of secure users (SU) and normal users (NU). The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NU's while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NU's follows the conventional water-filling principle, the power allocation for SU's depends on both its own channel gain and the largest channel gain among others. We also design a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU's and secrecy rate for SU at different power consumptions.","Title: An Auction Approach to Distributed Power Allocation for Multiuser Cooperative Networks\nYear: 2012\n\nAbstract: This paper studies a wireless network where multiple users cooperate with each other to improve the overall network performance. Our goal is to design an optimal distributed power allocation algorithm that enables user cooperation, in particular, to guide each user on the decision of transmission mode selection and relay selection. Our algorithm has the nice interpretation of an auction mechanism with multiple auctioneers and multiple bidders. Specifically, in our proposed framework, each user acts as both an auctioneer (seller) and a bidder (buyer). Each auctioneer determines its trading price and allocates power to bidders, and each bidder chooses the demand from each auctioneer. By following the proposed distributed algorithm, each user determines how much power to reserve for its own transmission, how much power to purchase from other users, and how much power to contribute for relaying the signals of others. We derive the optimal bidding and pricing strategies that maximize the weighted sum rates of the users. Extensive simulations are carried out to verify our proposed approach.","Title: Massive MIMO Multicasting in Noncooperative Cellular Networks\nYear: 2013\n\nAbstract: We study physical layer multicasting in cellular networks where each base station (BS) is equipped with a very large number of antennas and transmits a common message using a single beamformer to multiple mobile users. The messages sent by different BSs are independent, and the BSs do not cooperate. We first show that when each BS knows the perfect channel state information (CSI) of its own served users, the asymptotically optimal beamformer at each BS is a linear combination of the channel vectors of its multicast users. Moreover, the optimal and explicit combining coefficients are obtained. Then we consider the imperfect CSI scenario where the CSI is obtained through uplink channel estimation in time-division duplex systems. We propose a new pilot scheme that estimates the composite channel, which is a linear combination of the individual channels of multicast users in each cell. This scheme is able to completely eliminate pilot contamination. The pilot power control for optimizing the multicast beamformer at each BS is also derived. Numerical results show that the asymptotic performance of the proposed scheme is close to the ideal case with perfect CSI. Simulation also verifies the effectiveness of the proposed scheme with finite number of antennas at each BS.","Title: Time Sharing Policy in Wireless Networks for Variable Rate Transmission\nYear: 2007\n\nAbstract: For most of wireless services with variable rate transmission, both average rate and rate oscillation are important performance metrics. One often needs to decide how much rate oscillation the service can tolerate to obtain a higher average rate. Service satisfaction for each user is quantified by an increasing and concave utility function of instantaneous transmission rate. It is capable of facilitating the resource allocation with flexible combinations of average rate and rate oscillation. Particularly, we are interested in maximizing the time-average aggregate utility by scheduling user transmissions in a time-shared wireless network. A resource allocation policy is developed, namely, time sharing (TS), to exploit the concavity of utility function and the fluctuation of channel gain. This is formulated as a constrained convex optimization problem. Our analysis shows that in the TS policy the optimal scheduler allows multiple users with relatively better channel conditions to share a same time frame in an adaptive time-division manner. In addition, the more concave the utility function is, the higher the probability of time frame sharing is. An extension to quantized time sharing with limited channel feedback (QTSL) for practical systems is all studied. Simulation results show that, two to three bits of channel state information (CSI) are sufficient for the performance of QTSL scheme to approach that of the optimal TS policy when the number of time slots in a time frame is not less than the number of users, especially, in high SNR region.","Title: A Generalized Gradient Scheduling Algorithm in Wireless Networks for Variable Rate Transmission\nYear: 2007\n\nAbstract: Average transmission rate and rate oscillation are two important performance metrics for most wireless services. Both are often needed to be optimized in multi-user scheduling and resource management. In this paper we introduce a utility function that increases with average rate but decreases with rate variance. It is capable of facilitating resource allocation with flexible combinations of the two performance metrics. A generalized gradient scheduling algorithm (GGSA) is then developed to maximize the proposed utility. It is shown that the best scheduler should maximize the sum of concave functions of instantaneous transmission rates in order to maximize the utility of average rate and rate oscillation. The scheduler reduces to the traditional gradient scheduling algorithm when the rate variance term in the new utility function is omitted. We analyze the dynamics of average transmission rates and rate variances using ordinary differential equation and show that GGSA is asymptotically optimal under the condition that the transmission rate vector, after an appropriate scaling, converges to a fixed vector as time goes into infinity.","Title: Superimposed XOR: Approaching Capacity Bounds of the Two-Way Relay Channels\nYear: 2010\n\nAbstract: In two-way relay channels, bitwise XOR and symbol-level superposition coding\nare two popular network-coding based relaying schemes. However, neither of them\ncan approach the capacity bound when the channels in the broadcast phase are\nasymmetric. In this paper, we present a new physical layer network coding\n(PLNC) scheme, called \\emph{superimposed XOR}. The new scheme advances the\nexisting schemes by specifically taking into account the channel asymmetry as\nwell as information asymmetry in the broadcast phase. We obtain its achievable\nrate regions over Gaussian channels when integrated with two known time control\nprotocols in two-way relaying. We also demonstrate their average maximum\nsum-rates and service delay performances over fading channels. Numerical\nresults show that the proposed superimposed XOR achieves a larger rate region\nthan both XOR and superposition and performs much better over fading channels.\nWe further deduce the boundary of its achievable rate region of the broadcast\nphase in an explicit and analytical expression. Based on these results, we then\nshow that the gap to the capacity bound approaches zero at high signal-to-noise\nratio.","Title: Relay Placement for Physical Layer Security: A Secure Connection Perspective\nYear: 2012\n\nAbstract: This work studies the problem of secure connection in cooperative wireless communication with two relay strategies, decode-and-forward (DF) and randomize-and-forward (RF). The four-node scenario and cellular scenario are considered. For the typical four-node (source, destination, relay, and eavesdropper) scenario, we derive the optimal power allocation for the DF strategy and find that the RF strategy is always better than the DF to enhance secure connection. In cellular networks, we show that without relay, it is difficult to establish secure connections from the base station to the cell edge users. The effect of relay placement for the cell edge users is demonstrated by simulation. For both scenarios, we find that the benefit of relay transmission increases when path loss becomes severer. © 2012 IEEE.","Title: Robust Relay Beamforming for Two-Way Relay Networks.\nYear: 2012\n\nAbstract: We study the design of robust relay beamforming for two-way relay networks by considering channel feedback errors. Our objective is to maximize the minimum worst-case signal-to-noise ratios (SNRs) of two sources subject to a total relay power budget. We first decompose this non-convex problem into a series of relay power minimization problems under minimum SNR constraints by using bisection search. Then the relay power minimization problem is recast to a semidefinite programming relaxation (SDR) problem. A suboptimal but efficient solution is finally obtained for the original design. A necessary condition for the power minimization problem to be feasible is also given. For the special case with perfect channel state information, an alternative algorithm is introduced to find the optimal beamformer, which has lower complexity than the existing method. © 2012 IEEE.","Title: QoS-aware policies for OFDM bidirectional transmission with decode-and-forward relaying\nYear: 2012\n\nAbstract: In this paper, we consider the orthogonal frequency division multiplexing (OFDM)-based bidirectional transmission where a pair of users exchange information with the assistance of a decode-and-forward (DF) relay. Each user can communicate with the other via three transmission modes: direct transmission, one-way relaying, and two-way relaying. We jointly optimize the transmission policies, including power allocation, transmission mode selection, and subcarrier-node assignment for maximizing the weighted sum rates of the two users with quality-of-service (QoS) guarantees. We formulate the joint optimization problem as a mixed integer programming problem. By using the dual method, we solve the problem efficiently in an asymptotically optimal manner. Particularly, we derive the capacity region of two-way DF relaying in parallel relay channels. Simulation results show that the proposed resource-allocation scheme can substantially improve system performance compared with the conventional schemes.","Title: Analysis of Differential Orthogonal Space-Time Block Codes Over Semi-Identical MIMO Fading Channels\nYear: 2006\n\nAbstract: We study the performance of differential orthogonal space-time block codes (OSTBC) over independent and semi-identically distributed block Rayleigh fading channels. In this semiidentical fading model, the channel gains from different transmit antennas to a common receive antenna are identically distributed, but the gains associated with different receive antennas are nonidentically distributed. Ar...","Title: End-to-End Resource Allocation in OFDM Based Linear Multi-Hop Networks\nYear: 2008\n\nAbstract: We study the end-to-end resource allocation in an OFDM based multi-hop network consisting of a one-dimensional chain of nodes including a source, a destination, and multiple relays. The problem is to maximize the end-to-end average transmission rate under a long-term total power constraint by adapting the transmission power on each subcarrier over each hop and the transmission time used by each hop in every time frame. The solution to the problem is derived by decomposing it into two subproblems: short-term time and power allocation given an arbitrary total power constraint for each channel realization, and total power distribution over all channel realizations. We show that the optimal solution has the following features: the power allocation on subcarriers over each hop has the water-filling structure and a higher water level is given to the hop with relatively poor channel condition; meanwhile, the fraction of transmission time allocated to each hop is adjusted to keep the instantaneous rates over all hops equal. To tradeoff between performance, computational complexity and signalling overhead, three suboptimal resource allocation algorithms are also proposed. Numerical results are illustrated under different network settings and channel environments.","Title: Power and Subcarrier Allocation for Physical-Layer Security in OFDMA-Based Broadband Wireless Networks\nYear: 2011\n\nAbstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink orthogonal frequency-division multiple access (OFDMA)-based broadband network with coexistence of secure users (SUs) and normal users (NUs). The SUs require secure data transmission at the physical layer while the NUs are served with conventional best-effort data traffic. The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NUs while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NUs follows the conventional water-filling principle, the power allocation for SUs depends on both its own channel gain and the largest channel gain among others. We also develop a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU and secrecy rate for SU at different power consumptions.","Title: Subcarrier-pair based resource allocation for cooperative multi-relay OFDM systems\nYear: 2010\n\nAbstract: In this paper, we study the joint allocation of three types of resources, namely, power, subcarriers and relay nodes, in multi-relay assisted dual-hop cooperative OFDM systems. All the relays adopt the amplify-and-forward protocol and assist the transmission from the source to destination simultaneously but on orthogonal subcarriers. The objective is to maximize the system transmission rate subject to individual power constraints on each node or a total network power constraint. We formulate such a problem as a subcarrier-pair based resource allocation that seeks the joint optimization of subcarrier pairing, subcarrier-pair-to-relay assignment, and power allocation. Using a dual approach, we solve this problem efficiently in an asymptotically optimal manner. Specifically, for the optimization problem with individual power constraints, the computational complexity is polynomial in the number of subcarriers and relay nodes, whereas the complexity of the problem with a total power constraint is polynomial in the number of subcarriers.We further propose two suboptimal algorithms for the former to trade off performance for complexity. Simulation studies are conducted to evaluate the average transmission rate and outage probability of the proposed algorithms. The impact of relay location is also discussed.","Title: Cooperative secret communication with artificial noise in symmetric interference channel\nYear: 2010\n\nAbstract: We consider the symmetric Gaussian interference channel where two users try to enhance their secrecy rates in a cooperative manner. Artificial noise is introduced along with useful information. We derive the power control and artificial noise parameter for two kinds of optimal points, max-min point and single user point. It is shown that there exists a critical value Pc of the power constraint, below which the max-min point is an optimal point on the secrecy rate region, and above which time-sharing between single user points achieves larger secrecy rate pairs. It is also shown that artificial noise can help to enlarge the secrecy rate region, in particular on the single user point.","Title: Optimal Linear Transceiver Designs for Cognitive Two-Way Relay Networks\nYear: 2013\n\nAbstract: This paper studies a cooperative cognitive radio network where two primary users (PUs) exchange information with the help of a secondary user (SU) that is equipped with multiple antennas and in return, the SU superimposes its own messages along with the primary transmission. The fundamental problem in the considered network is the design of transmission strategies at the secondary node. It involves three basic elements: first, how to split the power for relaying the primary signals and for transmitting the secondary signals; second, what two-way relay strategy should be used to assist the bidirectional communication between the two PUs; third, how to jointly design the primary and secondary transmit precoders. This work aims to address this problem by proposing a transmission framework of maximizing the achievable rate of the SU while maintaining the rate requirements of the two PUs. Three well-known and practical two-way relay strategies are considered: amplify-and-forward (AF), bit level XOR based decode-and-forward (DF-XOR) and symbol level superposition coding based DF (DF-SUP). For each relay strategy, although the design problem is non-convex, we find the optimal solution by using certain transformation techniques and optimization tools such as semidefinite programming (SDP) and second-order cone programming (SOCP). Closed-form solutions are also obtained under certain conditions. Simulation results show that when the rate requirements of the two PUs are symmetric, by using the DF-XOR strategy and applying the proposed optimal precoding, the SU requires the least power for relaying and thus reserves the most power to transmit its own signal. In the asymmetric scenario, on the other hand, the DF-SUP strategy with the corresponding optimal precoding is the best.","Title: Distributed sparse channel estimation for OFDM systems with high mobility\nYear: 2013\n\nAbstract: Channel estimation for an orthogonal frequency-division multiplexing (OFDM) broadband system operating with high mobility is very challenging. This is mainly due to the significant Doppler spread, inherent in a time-frequency doubly-selective (DS) channel. Consequently, a large number of channel coefficients must be estimated, forcing the need for allocating a large number of pilot subcarriers. To address this problem, we propose a novel channel estimation method based on basis expansion models (BEMs) and distributed compressive sensing (DCS) theory. To be specific, we develop a two-stage sparse BEM coefficients estimation method, which can effectively combat the Doppler spread and enable accurate channel estimation with dramatically reduced number of pilot subcarriers. The numerical results reveal that, in a typical LTE system configuration, the proposed scheme can increase the spectral efficiency by 40% and achieve a 6 dB gain in terms of normalized mean square error (NMSE), both compared to the conventional scheme.","Title: End-to-end outage minimization in OFDM based linear relay networks\nYear: 2009\n\nAbstract: Multi-hop relaying is an economically efficient architecture for coverage extension and throughput enhancement in future wireless networks. OFDM, on the other hand, is a spectrally efficient physical layer modulation technique for broadband transmission. As a natural consequence of combining OFDM with multi-hop relaying, the allocation of perhop subcarrier power and per-hop transmission time is crucial in optimizing the network performance. This paper is concerned with the end-to-end information outage in an OFDM based linear relay network. Our goal is to find an optimal power and time adaptation policy to minimize the outage probability under a long-term total power constraint. We solve the problem in two steps. First, for any given channel realization, we derive the minimum short-term power required to meet a target transmission rate. We show that it can be obtained through two nested bisection loops. To reduce computational complexity and signalling overhead, we also propose a sub-optimal algorithm. In the second step, we determine a power threshold to control the transmission on-off so that the long-term total power constraint is satisfied. Numerical examples are provided to illustrate the performance of the proposed power and time adaptation schemes with respect to other resource adaptation schemes.","Title: V-OFDM: On Performance Limits over Multi-Path Rayleigh Fading Channels\nYear: 2011\n\nAbstract: As a bridge of connecting orthogonal frequency division multiplexing (OFDM) with single-carrier frequency domain equalization (SC-FDE) techniques, Vector OFDM (V-OFDM) provides significant flexibility in system design. This paper presents an analytical study of V-OFDM over multi-path fading channels. Our goal is to investigate the diversity gain and coding gain of each vector block (VB) in V-OFDM so as to ultimately reveal its performance limits over fading channel. By using algebraic number theory tools, we rigorously prove for the first time that a majority of VBs in V-OFDM can surely realize the diversity gain of min {M,G} , where M is the length of each VB, and G is the total number of channel taps. Furthermore, some specific VBs, whose length equals the total number of channel taps, can not only harvest the maximum diversity gain but also achieve the maximum coding gain. It is further demonstrated that, even though VBs fail to benefit from additional diversity gain when M exceeds G, they can enjoy significantly increased coding gains. Our analysis concludes that it is preferable to choose the length of VBs to be equal to the number of channel taps in consideration of both overall system performance and computational complexity.","Title: Precoding Strategy Selection for Cognitive MIMO Multiple Access Channels Using Learning Automata\nYear: 2010\n\nAbstract: In this paper, we study the quantized precoding strategy selection for multiple-input multiple-output (MIMO) multiple access channels (MAC) in cognitive radio (CR) networks through a game-theoretic perspective. Since the secondary users in such system are difficult to be coordinated by a centralized authority, they are noncooperative and attempt to maximize their own payoffs selfishly in a distributed method. We propose a noncooperative precoding strategy selection game and find that it is a potential game which possesses at least one pure strategy Nash equilibrium. A decentralized learning algorithm with a small amount of feedback is proposed to obtain Nash equilibrium. We prove that the proposed algorithm can converge to a pure strategy Nash equilibrium. Simulation results are provided to verify our analysis.","Title: An efficient beamforming scheme for generalized MIMO two-way X relay channels\nYear: 2013\n\nAbstract: Recently, a multiple-input multiple-output (MIMO) two-way X relay channel, where two groups of source nodes each having 2 nodes exchange independent messages via a common relay node, was studied in [1]. In this paper, we extend it to the generalized MIMO two-way X relay channel, where m ≥ 2 and n ≥ 2 source nodes are contained in two groups, respectively. Based on signal space alignment, a new beamforming scheme is proposed to maximize the minimum effective signal to interference plus noise ratios (SINRs) among all data streams. The beamforming vectors are designed by an iterative algorithm in which a closed-form solution is obtained in each step. Moreover, we show that the power allocation problem given the shape of the beamformers can be transformed as a linear programming problem. Simulation results show that the proposed beamforming scheme can achieve significantly better error performance than random beamforming schemes subject to signal space alignment only.","Title: The New Interference Alignment Scheme for the MIMO Interference Channel\nYear: 2010\n\nAbstract: In this paper, we propose a new interference alignment (IA) scheme designing jointly the linear transmitter and receiver for the MIMO interference channel system, using minimum total mean square error criterion, subject to individual transmit power constraints. We show that transmitter and receiver under such criterion could be realized through a joint iterative algorithm. The convergence of the proposed algorithm is discussed. We also proposed a robust MMSE-based iterative design with imperfect channel state information (CSI). The proposed robust MMSE-based iterative interference alignment scheme is shown to be less sensitive to channel estimation errors. Simulation results show that the proposed schemes outperform the existing IA schemes with fast convergence.","Title: Closed-Form Performance Of Mfsk Signals With Diversity Reception Over Non-Identical Fading Channels\nYear: 2007\n\nAbstract: This paper provides a comprehensive study on the error performance of noncoherent orthogonal M-ary frequency shift-keying (FSK) signals with various diversity combining schemes over fading channels. The diversity branches are assumed to be independent and non-identically distributed (i.n.d) Rayleigh fading. Closed-form expressions for the symbol error probability with an arbitrary diversity order and any modulation level are obtained for optimal combining (OC), equal gain combining (EGC) and log-likelihood ratio based selection combining (SC-LLR). Our analytical results show that EGC performs closely to OC over slightly unbalanced channels, whereas for highly unbalanced channels SC-LLR performs more closely to OC than EGC.","Title: Coordinated beamforming design in multicell multicast networks\nYear: 2012\n\nAbstract: In this paper, we study the physical layer multicasting in multicell networks, where each base station equipped with multiple antennas transmits a common message using a single beamformer to multiple users equipped with a single antenna in the same cell. We consider the quality-of-service (QoS) beamforming for minimizing the total power consumption while guaranteeing that the signal-to-interference-plus-noise ratio (SINR) at each user is above a predetermined threshold. Based on the decomposition theory, we propose a novel decentralized algorithm to implement the coordinated beamforming with limited information sharing among different base stations. The algorithm is guaranteed to converge and in most cases it converges to the optimal solution. Simulation results demonstrate significant advantages of the proposed coordinated beamforming over conventional beamforming.","Title: Pairwise Check Decoding for LDPC Coded Two-Way Relay Block Fading Channels.\nYear: 2012\n\nAbstract: Partial decoding has the potential to achieve a larger capacity region than full decoding in two-way relay (TWR) channels. Existing partial decoding realizations are however designed for Gaussian channels and with a static physical layer network coding (PLNC). In this paper, we propose a new solution for joint network coding and channel decoding at the relay, called pairwise check decoding (PCD), ...","Title: Capacity Analysis and Power Allocation over Non-Identical MISO Rayleigh Fading Channels\nYear: 2008\n\nAbstract: We analyze the capacity of a multiple-input single- output system over Rayleigh fading channels. The channels are assumed to be independent and non-identically distributed. Simple, explicit and closed-form expressions of ergodic mutual information and outage probability are obtained. Moreover, two suboptimal but efficient analytical power allocation schemes for mutual information maximization and outage minimization are derived, respectively. In specific, for mutual information maximization, more power is assigned to those channels with higher channel variances, while for outage minimization the power allocation scheme follows the water-filling principle.","Title: Trellis-coded differential unitary space-time modulation over flat fading channels\nYear: 2003\n\nAbstract: Coding and modulation for multiple-antenna systems have gained much attention in wireless communications. This paper investigates a noncoherent trellis-coded scheme based on differential unitary space-time modulation when neither the transmitter nor the receiver know the channel. In a time-varying flat Rayleigh fading environment, we derive differentially noncoherent decision metrics and obtain performance measures for systems with either an ideal interleaver or no interleaver. We demonstrate that with an ideal interleaver, the system performance is dominated by the minimum Hamming distance of the trellis code, while without an interleaver, the performance is dominated by the minimum free squared determinant distance (a novel generalization of the Euclidean distance) of the code. For both cases, code construction is described for Ungerboeck-type codes. Several examples that are based on diagonal cyclic group constellations and offer a good tradeoff between the coding advantage and trellis complexity are provided. Simulation results show that, by applying the soft-decision Viterbi decoder, the proposed scheme can achieve very good performance even with few receive antennas. Extensions to trellis-coded differential space-time block codes are also discussed.","Title: Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems\nYear: 2008\n\nAbstract: Most existing work on adaptive allocation of sub- carriers and power in multiuser orthogonal frequency division multiplexing (OFDM) systems has focused on homogeneous traffic consisting solely of either delay-constrained data (guaranteed service) or non-delay-constrained data (best-effort service). In this paper, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and non-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the users with DC traffic under a total transmit power constraint. Through our analysis we show that the optimal power allocation over subcarriers follows a multi-level water-filling principle; moreover, the valid candidates competing for each subcarrier include only one NDC user but all DC users. By converting this combinatorial problem with exponential complexity into a convex problem or showing that it can be solved in the dual domain, efficient iterative algorithms are proposed to find the optimal solutions. To further reduce the computational cost, a low-complexity suboptimal algorithm is also developed. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of service outage probability, achievable transmission rate pairs for DC and NDC traffic, and multiuser diversity.","Title: Extended Space-Time Block Coding with Transmit Antenna Selection over Correlated Fading Channels\nYear: 2007\n\nAbstract: A new space-time block coded transmit antenna selection scheme over spatially correlated fading channels is presented. This scheme allows two or more transmit antennas to simultaneously use one radio frequency frontend. A system with four transmit antennas is considered in particular. The four antennas are selectively grouped into two subsets. Alamouti code is then applied on top of the subsets as if each was a single antenna. This scheme is shown to be more efficient than the conventional transmit antenna selection combined with Alamouti code in correlated channels. Moreover, it lowers the bitrate of the feedback channel.","Title: Outage performance analysis of two-way relay system with multi-antenna relay node\nYear: 2012\n\nAbstract: This paper presents an analytical study on the outage performance of amplify-and-forward (AF) two-way relay system with multi-antenna relay node (RN). Two major bidirectional protocols, i.e., two time slots multiple access broadcast (MABC) protocol and three time slots time division broadcast (TDBC) protocol, are considered. For both considerations, we first assume that instantaneous channel-state-information (CSI) is unavailable at RN, thus RN just simply uses the fixed relay gain derived from statistical CSI to scale the received signals before forwarding. We then consider the scenario where RN can obtain the instantaneous CSI to perform the zero-forcing (ZF) relay precoding. The closed-form expressions of outage probability are derived for all cases. Based on these expressions, the diversity-multiplexing tradeoff (DMT) is further obtained for the MABC protocol. The analytical results show that, for non-precoding MABC scheme, the diversity order is only 1, which is independent to the relay antenna number M. While for the ZF-precoding case, the diversity order of M - 1 can be obtained.","Title: MSE-based transceiver designs for the MIMO interference channel\nYear: 2010\n\nAbstract: Interference alignment (IA) has evolved as a powerful technique in the information theoretic framework for achieving the optimal degrees of freedom of interference channel. In practical systems, the design of specific interference alignment schemes is subject to various criteria and constraints. In this paper, we propose novel transceiver schemes for the MIMO interference channel based on the mean square error (MSE) criterion. Our objective is to optimize the system performance under a given and feasible degree of freedom. Both the total MSE and the maximum per-user MSE are chosen to be the objective functions to minimize. We show that the joint design of transmit precoding matrices and receiving filter matrices with both objectives can be realized through efficient iterative algorithms. The convergence of the proposed algorithms is proven as well. Simulation results show that the proposed schemes outperform the existing IA schemes in terms of BER performance. Considering the imperfection of channel state information (CSI), we also extend the MSE-based transceiver schemes for the MIMO interference channel with CSI estimation error. The robustness of the proposed algorithms is confirmed by simulations.","Title: Improved design criteria and new trellis codes for space-time coded modulation in slow flat fading channels\nYear: 2001\n\nAbstract: The design criteria for space-time codes under slow flat Rayleigh fading environments are well known to be the rank criterion and the determinant criterion. However, the derivation of these two criteria is based on the assumption that the signal-to-noise ratio (SNR) is sufficiently high. Hence these criteria are loose when the SNR does not satisfy this assumption. In this letter, we consider this practical issue and derive tighter design criteria for moderate and low SNRs. Some new space-time trellis codes are found based on the new criteria through computer search. Simulation results show that these codes outperform existing codes under their designed SNR conditions.","Title: End-to-End Outage Probability Minimization in OFDM Based Linear Multi-Hop Networks\nYear: 2008\n\nAbstract: This paper is concerned with the end-to-end transmission outage in an OFDM based wireless multi-hop network. The network consists of a source node, a destination node, and a set of serial relay nodes. Transmission outage occurs when the end-to-end transmission rate is less than a target rate. Our goal is to find an optimal power and time control policy to minimize the outage probability at a target end-to-end data rate under a long-term total power constraint. The problem is solved in two steps. First, for any given channel realization, we derive the minimum total power required to meet the target rate by varying the transmission power and time allocated to each hop. This is formulated as a convex optimization problem and is solved efficiently. We then compare the required minimum total power for each channel realization with a power threshold. If the threshold is exceeded, the transmission is turned off. The optimal threshold is chosen to meet the long-term total power constraint. Two suboptimal power and time control policies are also presented and compared with the optimal policy by simulation.","Title: Joint scheduling and relay selection in one- and two-way relay networks with buffering\nYear: 2009\n\nAbstract: In most wireless relay networks, the source and relay nodes transmit successively via fixed time division (FTD) and each relay forwards a packet immediately upon receiving. In this paper we enable the buffering capability of relay nodes and propose a framework for joint scheduling and relay selection. The goal is to maximize the system long-term throughput by fully exploiting multi-user diversity in the network. We develop two joint scheduling and relay selection (JSRS) algorithms for unidirectional and bidirectional traffic, respectively. The novel cross-layer relay selection metrics which our algorithms are based upon take into account both instantaneous channel conditions and the queuing status. We also demonstrate that the proposed JSRS can be realized in a distributed way without explicit coordination among the network nodes. Extensive simulation is carried out to evaluate the performance of the proposed JSRS with buffering in comparison with traditional FTD without buffering. Typical throughput enhancements up to 101% and 110% are observed in one-way and two-way relay networks respectively, at low signal-to-noise ratio (0 dB).","Title: On Degrees of Freedom of Cognitive Networks with User Cooperation.\nYear: 2012\n\nAbstract: In this letter, the degrees of freedom (DoF) outer bound is characterized for cognitive networks. We have devised an interference alignment scheme with appropriate cooperation between primary users and secondary users to achieve the DoF outer bound. Moreover, to encourage the primary users to participate in the proposed cooperation, we also design two aided interference alignment schemes, where bo...","Title: Resource Allocation in Open Access OFDMA Femtocell Networks\nYear: 2012\n\nAbstract: Open access is an efficient approach to reduce cross-tier interference in femtocell networks. In this paper, we study resource allocation in open access OFDMA femtocell networks to guarantee QoS of the neighboring macrocell user (MU) in Dead Zone and limit cross-tier interference to other MUs. A new resource allocation method is proposed to improve performance of both neighboring MU and femtocell users (FU). In specific, the subchannel set originally assigned to the MU may overlap the subchannel set occupied by FAP and cause cross-tier interference. The overlapped subchannel set is freed by macro base station (MBS) after MU resigns and joins the nearby femtocell. Then the subchannel and power resources in the femtocell are re-allocated. We leverage cognitive radio (CR) technology in femtocell networks and propose an asymptotically optimal resource allocation algorithm using dual decomposition methods. Simulation results show that the proposed algorithm for the open access scheme can achieve higher transmission rate in contrast to the closed access scheme.","Title: An Estimation Algorithm Of Channel State Transition Probabilities For Cognitive Radio Systems\nYear: 2008\n\nAbstract: In this paper, an estimation algorithm of channel state transition probabilities in Markov channel model for cognitive radio systems is proposed. The framework of POMDP is adopted to solve the problem of channel selection. Maximum likelihood method is used to estimate the channel state transition probabilities, which is crucial to POMDP. Central Limit Theorem is introduced to get the relationship between the precision, sample times and the channel state transition probability values. The simulation results show the reliability of the estimation results.","Title: A spectrum access game in bidirectional cognitive relay networks\nYear: 2010\n\nAbstract: We consider a cognitive relay network where two secondary users can access the unutilized spectrum and conduct bidirectional communication via the help of primary users. The primary users are regarded as relay nodes of the secondary users and adopt amplify-and-forward relaying strategy. Physical-layer network coding is used when both secondary users select the same relay. The spectrum access problem in the considered system model is defined as joint relay selection and discrete power control. We formulate the problem as a noncooperative game where the players are the secondary users and the common payoff function takes both transmission rate and power consumption into account. The proposed game falls into the framework of potential games where at least one pure strategy Nash equilibrium (NE) exists. Furthermore, the social optimal solution is also a pure strategy NE of the proposed game. We then propose a distributed algorithm based on learning automata to achieve the pure strategy NE. Numerical results show that the proposed algorithm has good convergence and near optimal performance.","Title: Degrees of Freedom of MIMO Multiway Relay Channel With Clustered Pairwise Exchange\nYear: 2015\n\nAbstract: In this paper, we consider a symmetric multiple-input-multiple-output (MIMO) multiway relay channel (mRC) with L clusters and K users per cluster operating in clustered pairwise data exchange. Each user is equipped with M antennas, and the relay is equipped with N antennas. The degrees of freedom (DoF) of the MIMO mRC has recently attracted much research interest. The DoF results under certain configurations of (L,K,M,N) have been reported. However, the DoF capacity of the MIMO mRC with an arbitrary network configuration is, in general, far from being well understood. In this regard, the main contribution of this paper is to propose a systematic signal alignment approach to jointly design the beamforming matrices at the users and the relay. Based on that, an achievable DoF is derived for the MIMO mRC with an arbitrary network configuration of (L,K,M,N). Our analysis revealed that the derived achievable DoF is piecewise linear in M and N alternately. Moreover, we showed that the DoF capacity can be achieved for M/N ∈ [1/LK(K-1) + 1/2, ∞) and M/N ∈ (0, Lq/LK(Lq-1)], where q = 2 ⌈K/2⌉.We further derived the asymptotic DoF as K or L → ∞. The DoF analysis in this paper can provide insights on the practical design of efficient communication mechanisms over multiterminal MIMO relay networks.","Title: Generalized Signal Alignment: On the Achievable DoF for Multi-User MIMO Two-Way Relay Channels\nYear: 2015\n\nAbstract: This paper studies the achievable degrees of freedom (DoF) for multi-user multiple-input multiple-output (MIMO) two-way relay channels, where there are K source nodes, each equipped with M antennas, one relay node, equipped with N antennas, and each source node exchanges independent messages with an arbitrary set of other source nodes via the relay. By allowing an arbitrary information exchange pattern, the considered channel model is a unified one. It includes several existing channel models as special cases: K-user MIMO Y channel, multipair MIMO two-way relay channel, generalized MIMO two-way X relay channel, and L-cluster MIMO multiway relay channel. Previous studies mainly considered the achievability of the DoF cut-set bound 2N at the antenna configuration N < 2M by applying signal alignment for network coding. This work aims to investigate the achievability of the DoF cut-set bound KM for the case N 2M. To this end, we first derive tighter DoF upper bounds for three special cases of the considered channel model. Then, we propose a new transmission framework, generalized signal alignment (GSA), to approach these bounds. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a compressed subspace at the relay. A necessary and sufficient condition to construct the relay compression matrix is given. We show that using GSA, the new DoF upper bound is achievable when i) N M 2 ( 0; 2 + 4 K(K1) ] [ [ K 2;+1 ) for the K-user MIMO Y channel; ii) N M 2 ( 0; 2 + 4 K ] [ [ K 2;+1 ) for the multi-pair MIMO two-way relay channel; iii) N M 2 ( 0; 2+ 8 K2 ] [ [ K2;+1 ) for the generalized MIMO two-way X relay channel. We also provide the antenna configuration regions for the general multiuser MIMO two-way relay channel to achieve the total DoF KM.","Title: Channel Estimation and Optimal Training Design for Correlated MIMO Two-Way Relay Systems in Colored Environment\nYear: 2014\n\nAbstract: In this paper, while considering the impact of the antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcast (BC) phase. By considering the Kroneckerstructured channel model, we derive the optimal linear minimum mean-square-error (LMMSE) channel estimators. The corresponding training designs for the MAC phase and the BC phase are then formulated and solved to improve channel estimation accuracy. For the general scenario of the training sequence design for both phases, two iterative training design algorithms are proposed that are verified to produce training sequences achieving near optimal channel estimation performance. Furthermore, for specific practical scenarios, where the covariance matrices of the channel or disturbances are of particular structures, the optimal training sequence design guidelines are obtained. The minimum required training lengths for channel estimation in both the MAC phase and the BC phase are also analyzed. Comprehensive simulations are carried out to demonstrate the effectiveness of the proposed training designs.","Title: Resource Allocation in Spectrum-Sharing OFDMA Femtocells With Heterogeneous Services\nYear: 2014\n\nAbstract: Femtocells are being considered a promising technique to improve the capacity and coverage for indoor wireless users. However, the cross-tier interference in the spectrum-sharing deployment of femtocells can degrade the system performance seriously. The resource allocation problem in both the uplink and the downlink for two-tier networks comprising spectrum-sharing femtocells and macrocells is investigated. A resource allocation scheme for cochannel femtocells is proposed, aiming to maximize the capacity for both delay-sensitive users and delay-tolerant users subject to the delay-sensitive users' quality-of-service constraint and an interference constraint imposed by the macrocell. The subchannel and power allocation problem is modeled as a mixed-integer programming problem, and then, it is transformed into a convex optimization problem by relaxing subchannel sharing; finally, it is solved by the dual decomposition method. Subsequently, an iterative subchannel and power allocation algorithm considering heterogeneous services and cross-tier interference is proposed for the problem using the subgradient update. A practical low-complexity distributed subchannel and power allocation algorithm is developed to reduce the computational cost. The complexity of the proposed algorithms is analyzed, and the effectiveness of the proposed algorithms is verified by simulations.","Title: A New DoF Upper Bound and Its Achievability for $K$-User MIMO Y Channels.\nYear: 2014\n\nAbstract: This work is to study the degrees of freedom (DoF) for the $K$-user MIMO Y channel. Previously, two transmission frameworks have been proposed for the DoF analysis when $N \\geq 2M$, where $M$ and $N$ denote the number of antennas at each source node and the relay node respectively. The first method is named as signal group based alignment proposed by Hua et al. in [1]. The second is named as signal pattern approach introduced by Wang et al. in [2]. But both of them only studied certain antenna configurations. The maximum achievable DoF in the general case still remains unknown. In this work, we first derive a new upper bound of the DoF using the genie-aided approach. Then, we propose a more general transmission framework, generalized signal alignment (GSA), and show that the previous two methods are both special cases of GSA. With GSA, we prove that the new DoF upper bound is achievable when $\\frac{N}{M} \\in \\left(0,2+\\frac{4}{K(K-1)}\\right] \\cup \\left[K-2, +\\infty\\right)$. The DoF analysis in this paper provides a major step forward towards the fundamental capacity limit of the $K$-user MIMO Y channel. It also offers a new approach of integrating interference alignment with physical layer network coding.","Title: Polar Coding for Secure Transmission in MISO Fading Wiretap Channels.\nYear: 2014\n\nAbstract: In this paper, we propose a polar coding scheme for secure communication over the multiple-input, single-output, single-antenna eavesdropper (MISOSE) fading channel. We consider the case of block fading channels with known eavesdropper channel state information (CSI) and the case of fading channels with known eavesdropper channel distribution information (CDI). We use the artificial noise assisted secure precoding method to maximize the secrecy capacity in the first case, and to overcome the unawareness of the eavesdropper CSI in the second case. We show that our proposed scheme can provide both reliable and secure communication over the MISOSE channel with low encoding and decoding complexity.","Title: On content-centric wireless delivery networks\nYear: 2014\n\nAbstract: The flux of social media and the convenience of mobile connectivity have created a mobile data phenomenon that is expected to overwhelm mobile cellular networks in the foreseeable future. Despite the advent of 4G/LTE, the growth rate of wireless data has far exceeded the capacity increase of mobile networks. A fundamentally new design paradigm is required to tackle the ever growing wireless data challenge. In this article, we investigate the problem of massive content delivery over wireless networks, and present a systematic view of content-centric network design and its underlying challenges. Toward this end, we first review some of the recent advancements in information-centric networking, which provide the basis of how media contents can be labeled, distributed, and placed across the networks. We then formulate the content delivery task into a content rate maximization problem over a shared wireless channel, which, in contrast to the conventional wisdom that attempts to increase the bit rate of a unicast system, maximizes the content delivery capability with a fixed amount of wireless resources. This conceptually simple change enables us to exploit the content diversity and network diversity by leveraging the abundant computation sources (through application-layer encoding, pushing and caching, etc.) within the existing wireless networks. A network architecture that enables wireless network crowdsourcing for content delivery is then described, followed by an exemplary campus wireless network that encompasses the above concepts.","Title: Graph theory and its applications to future network planning: software-defined online small cell management\nYear: 2015\n\nAbstract: Network planning is facing new and critical challenges due to ad hoc deployment, unbalanced and drastically varying traffic demands, as well as limited backhaul and hardware resources in emerging small cell architectures. We discuss the application of graph theory to address the challenges. A clique-based software-defined online network management approach is proposed that captures traffic imbalance and fluctuation of small cells and optimally plans frequencies, infrastructures, and network structure at any instant. Its applications to three important small cell scenarios of cloud radio, point-to-point microwave backhaul, and interoperator spectrum sharing are demonstrated. Comparison studies show that in each of the scenarios, this new approach is able to significantly outperform conventional static offline network planning schemes in terms of throughput and satisfaction levels of small cells with regard to allocated bandwidths. Specifically, the throughput can be improved by 155 percent for the cloud radio scenario and 110.95 percent for the microwave backhaul scenario. The satisfaction level can be improved by 40 percent for interoperator spectrum sharing.","Title: Outage Analysis of Cooperative Secrecy Multicast Transmission\nYear: 2014\n\nAbstract: This work considers a multicast network in the presence of an eavesdropper. We investigate a cooperative multicast scheme which allows the users to function as relays. The secure outage behavior of this scheme is studied and the analytical expression of secure outage probability is derived. Numerical results show that the proposed cooperative multicast scheme outperforms the direct multicast without cooperation in terms of secure outage probability.","Title: A Decentralized Sleep Mechanism in Heterogeneous Cellular Networks With QoS Constraints\nYear: 2014\n\nAbstract: We introduce a sleep mechanism for energy efficiency in heterogeneous cellular networks, where macro base stations and small base stations coexist in the same frequency band. The strategy is to put high-power macro base stations into sleep mode and off-load the users to low-power small base stations or neighboring macro base stations. To do so, we first formulate a joint optimization problem to minimize the total energy consumption while maintaining the QoS of users. Then we decouple it into two subproblems: user association and resource allocation, and macro base station sleep mechanism. We propose a modified many-to-one matching algorithm to solve the first one and a voting-based dynamic sleep mechanism for the second one. Simulation results show that our scheme has both lower energy consumption and lower user blocking ratio compared with existing sleep mechanisms.","Title: Partition function game for rate optimization in random interference networks\nYear: 2012\n\nAbstract: Interference is one of the main limiting factors in wireless communication networks for system performance nowadays. In this paper, we study a coalitional game approach for rate optimization in a random interference networks where multiple transmission pairs transmit concurrently. We model the rate optimization problem as a partition function game. All transmission pairs form separated coalitions, and the pairs cooperate to transmit within each coalition. An iterative coalition structure generation algorithm is proposed to obtain partitions. This algorithm allows each transmission pair to make individual decision whether to stay in or depart from its current coalition. We prove that the proposed iterative algorithm can achieve a Nash-stable partition. In each coalition, we adopt the duality features of broadcast channel (BC) and multi-access channel (MAC) to maximize the sum-rate. Simulation results show that the proposed algorithm can improve the network performance significantly compared with location-based static partition forms.","Title: Energy-efficient cross-layer design of delay-aware MIMO systems\nYear: 2014\n\nAbstract: In this paper, we propose a cross-layer design model for multiple input and multiple output (MIMO) cellular systems, to solve the problem of energy efficient communications with delay demand. We first investigate the energy efficient multiple quadrature amplitude modulation (MQAM) constellation size for each transmission stream. With the demand of the packet delay, then we propose an adaptive MIMO/SIMO transmission mode by exploiting the intrinsic relationship between the upper layer packet delay and the constellation size, the symbol error rate (SER) from the physical layer. Simulations show that in order to maximize the energy efficiency and offer different Quality of Service (QoS) of delay simultaneously, a user should adaptively choose the constellation size as well as the transmission mode. In this framework, the tradeoff between energy efficiency and delay demand are well demonstrated.","Title: Optimal training design and individual channel estimation for MIMO two-way relay systems in colored environment\nYear: 2014\n\nAbstract: In this paper, while considering the impact of antenna correlation and the interference from neighboring users, we study the problem of channel estimation and training sequence design in multi-input multi-output (MIMO) two-way relaying (TWR) systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) and the broadcast (BC) phases. By deriving the optimal linear minimum mean-square-error estimators, the corresponding training design problems for the MAC and BC phases are formulated and solved. Subsequently, algorithms and, in some special cases, closed-form solutions for obtaining the optimal training sequences for channel estimation in TWR systems are derived. Moreover, to further reduce channel estimation overhead, the minimum required length of the training sequences are determined. Simulation results verify the effectiveness of the proposed training designs in improving channel estimation performance in TWR systems.","Title: Channel estimation and carrier recovery in the presence of phase noise in OFDM relay systems\nYear: 2014\n\nAbstract: In this paper, we analyze joint channel, carrier frequency offset (CFO), and phase noise estimation in orthogonal frequency division multiplexing (OFDM) relaying networks. To achieve this goal, a detailed transmission framework involving both training and data symbols is first presented. Next, a novel algorithm that applies the training symbols to jointly estimate the channel responses, CFO, and phase noise parameters based on the maximum a posteriori criterion is proposed. Additionally, to evaluate the performance of the proposed channel estimation and carrier recovery algorithms, we analyze the ambiguities among the estimated parameters. Based on this analysis, a new Hybrid Cramér-Rao Lower Bound (HCRLB) is derived, which can effectively avoid such ambiguities. The simulation results show that the proposed estimation algorithm can achieve a performance close to the derived HCRLB.","Title: Optimal energy-efficient transmission for fading channels with an energy harvesting transmitter\nYear: 2014\n\nAbstract: This paper investigates the optimal energy-efficient transmission policy of multi-channels in energy harvesting systems. We configure the transmitter with the active mode in which the energy cost includes the basic operation cost and transmission cost and signal processing cost, while with the sleep mode only counting the basic operation cost. Then the energy efficiency maximization problem of joint transmission time and power allocation is formulated and studied in the offline manner. Based on the fractional optimization theory, we transform the original fractional optimization problem into a series of subtractive-form optimization problems which are then further transformed into convex optimization problems. Then characteristics of the optimal solution are described based on the analysis of transmission time and power allocation. Finally, a special case without considering the basic operation cost as previous works assumed is studied. We find that the optimal policy results a best subchannel scheduling which can be viewed as the peaky transmission. Through this, the energy cost of the sleep mode in previous case can be interpreted as the switching operation cost.","Title: Massive MIMO multicasting in noncooperative multicell networks\nYear: 2014\n\nAbstract: We study the massive MIMO (multiple-input multiple-output) multicast transmission in multicell networks, where each base station (BS) is equipped with a large-scale antenna array and transmits a common message using a single beamformer to multiple mobile users. We first consider the case when each BS knows the perfect channel state information (CSI) of all its served users. We show that the asymptotically optimal beamformer structure at each BS is a linear combination of the channel vectors of its multicast users. The optimal combination coefficients are also obtained in closed form. Then we consider the imperfect CSI scenario where each BS obtains the CSI through uplink channel estimation. We propose a novel pilot scheme that estimates the compound channel rather than the individual channels of multicast users in each cell. This scheme is able to completely eliminate pilot contamination. The optimal power control of pilot transmission is also derived. Numerical results show that the performance of the proposed pilot scheme with pilot power control is close to that of the perfect CSI case.","Title: Dynamic uplink/downlink configuration using Q-learning in femtocell networks\nYear: 2014\n\nAbstract: With increasingly popular services containing asymmetric uplink (UL) and downlink (DL) traffic, Time-Division Duplexing (TDD) shows more advantages than Frequency-Division Duplexing (FDD) in wireless cellular networks due to its flexibility of dynamic UL/DL configuration. A major technical challenge in TDD is how to optimize the UL/DL switching point for each individual cell to meet its asymmetric traffic demand without causing severe cross-link interference. In this paper, we formulate the dynamic UL/DL configuration problem in non-cooperative femtocell networks as a multi-agent Q-learning process. Each femto base station (FBS) is treated as an agent. It senses its local interference environment and then takes an action. The optimal UL/DL switching policy is learned gradually by each FBS through trial and error with the objective of minimizing the overall packet transmission time. The proposed Q-learning based method takes both the asymmetric traffic demands and the interference into consideration. Simulation results show that our proposed method can achieve higher cell average packet throughput than the existing queue-aware dynamic TDD method and the fixed TDD method.","Title: Power Control for MIMO Diversity Systems With Nonidentical Rayleigh Fading\nYear: 2009\n\nAbstract: We investigate the performance limits and associated power-allocation problems in a multiple-antenna diversity system with statistical channel information available at the transmitter. The channels are assumed to be independent and nonidentically distributed Rayleigh fading. By studying both ergodic mutual information and information outage, we derive two simple and near-optimal power-allocation schemes. Specifically, for ergodic information rate maximization in a system with multiple transmit antennas and a single receive antenna, the proposed power control only depends on the ratios between channel gains and is independent of the total transmit signal-to-noise ratio (SNR). Meanwhile, for information outage minimization in a system with an arbitrary number of transmit and receive antennas, the proposed power allocation follows the water-filling principle and pours more power into the transmit antenna with a larger geometric mean of channel gains.","Title: Channel Estimation, Carrier Recovery, and Data Detection in the Presence of Phase Noise in OFDM Relay Systems.\nYear: 2016\n\nAbstract: Due to its time-varying nature, oscillator phase noise can significantly degrade the performance of the channel estimation, carrier recovery, and data detection blocks in high-speed wireless communication systems. In this paper, we propose a new data-aided joint channel, carrier frequency offset (CFO) and phase noise estimator for orthogonal frequency division multiplexing (OFDM) relay systems. Fo...","Title: Joint Tx/Rx Energy-Efficient Scheduling in Multi-Radio Wireless Networks: A Divide-and-Conquer Approach.\nYear: 2016\n\nAbstract: Most of the existing works on energy-efficient wireless communications only consider the transmitter (Tx) or the receiver (Rx) side power consumption, but not both. Moreover, the circuit power consumption is often assumed to be constant regardless of the transmission rate or the bandwidth. In this paper, we investigate the system-level energy-efficient transmission in multi-radio access networks b...","Title: Energy-Efficient Resource Allocation for Wireless Powered Communication Networks.\nYear: 2016\n\nAbstract: This paper considers a wireless powered communication network (WPCN), where multiple users harvest energy from a dedicated power station and then communicate with an information receiving station. Our goal is to investigate the maximum achievable energy efficiency (EE) of the network via joint time allocation and power control while taking into account the initial battery energy of each user. We f...","Title: Caching Incentive Design In Wireless D2d Networks: A Stackelberg Game Approach\nYear: 2016\n\nAbstract: Caching in wireless device-to-device (D2D) networks can be utilized to offload data traffic during peak times. However, the design of incentive mechanisms is challenging due to the heterogeneous preference and selfish nature of user terminals (UTs). In this paper, we propose an incentive mechanism in which the base station (BS) rewards those UTs that share contents with others using D2D communication. We study the cost minimization problem for the BS and the utility maximization problem for each UT. In particular, the BS determines the rewarding policy to minimize his total cost, while each UT aims to maximize his utility by choosing his caching policy. We formulate the conflict among UTs and the tension between the BS and the UTs as a Stackelberg game. We show the existence of the equilibrium and propose an iterative gradient algorithm (IGA) to obtain the Stackelberg Equilibrium. Extensive simulations are carried out to evaluate the performance of the proposed caching scheme and comparisons are drawn with several baseline caching schemes with no incentives. Numerical results show that the caching scheme under our incentive mechanism outperforms other schemes in terms of the BS serving cost and the utilities of the UTs.","Title: Position-Based Compressed Channel Estimation and Pilot Design for High-Mobility OFDM Systems\nYear: 2015\n\nAbstract: With the development of high-speed trains (HSTs) in many countries, providing broadband wireless services in HSTs is crucial. Orthogonal frequency-division multiplexing (OFDM) has been widely adopted for broadband wireless communications due to its high spectral efficiency. However, OFDM is sensitive to the time selectivity caused by high-mobility channels, which costs much spectrum or time resour...","Title: Resource-Efficient Data Gathering in Sensor Networks for Environment Reconstruction.\nYear: 2015\n\nAbstract: Environment reconstruction is to rebuild the physical environment in the cyberspace using the sensory data collected by sensor networks, which is a fundamental method for human to understand the physical world in depth. A lot of basic scientific work such as nature discovery and organic evolution heavily relies on the environment reconstruction. However, gathering large amount of environmental dat...","Title: Generalized signal alignment for high mobility OFDM channels\nYear: 2015\n\nAbstract: Generalized signal alignment (GSA) is recently proposed as a new transmission framework to achieve the maximum degrees of freedom in multi-user MIMO two-way relay channels. In this paper, we apply GSA in high mobility OFDM systems. To handle the inter-carrier interference (ICI) resulted from large Doppler frequency shift effectively, we propose subcarrier extension (SE)-GSA. Its idea is to treat each subcarrier as a virtual antenna and then apply GSA in the extended virtual MIMO channel. We take the MIMO two-way X relay channel as the system model. It well models to the scenario where a high speed train enters the edge of two adjacent cells and two mobile users inside the train are communicating with the base stations (BSs) through a relay station deployed on the train carriage. By jointly designing the compression matrix and precoding matrices in the virtual antenna domain, both inter-user interference and inter-carrier interference can be managed together. To reduce the computation complexity at the relay, a new method is proposed to design the precoding matrix at each source node. Simulation results demonstrate that the proposed SE-GSA achieves 25% and 66% higher throughput than the conventional signal alignment (SA) and time division duplex (TDD) transmission schemes, respectively, at high SNR with the train moving speed of 500 km/h.","Title: Statistics-based channel estimation and ici mitigation in OFDM system over high mobility channel\nYear: 2014\n\nAbstract: In this paper, we propose a statistics-based channel estimation and inter-carriers interference (ICI) mitigation scheme for the orthogonal frequency division multiplexing (OFDM) transmission over high speed railway communication. The proposed scheme offers a new channel estimation method based on compressed sensing by utilizing the sparsity of high speed train (HST) in the time domain channel. The wireless channel is expressed by a weighted time-domain channel interpolation. The interpolation weights are designed according to the channel statistics, and the position of the selected parameter of each path is designed based on coherence of the model structure. Furthermore, by utilizing the channel statistics, we develop the receive post-processing in the receiver for ICI mitigation. Numerical and simulation results verify the effectiveness of the proposed schemes.","Title: Compressed channel estimation with joint pilot symbol and placement design for high mobility OFDM systems\nYear: 2014\n\nAbstract: High mobility introduces significant Doppler frequency spread and hence imposes great challenge to channel estimation in orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose a new low coherence compressed channel estimation method for OFDM systems in the high mobility environment. Based on the compressed sensing (CS) coherence minimization criterion, we propose a new pilot design algorithm using the discrete stochastic optimization method to improve the estimation performance. The pilot symbol and pilot placement are jointly designed to obtain the optimal pilot. Numerical results demonstrate that the proposed method has a fast convergency property and achieves better MSE performance than existing channel estimation methods over high mobility channels.","Title: Content-Centric Multicast Beamforming in Cache-Enabled Cloud Radio Access Networks.\nYear: 2015\n\nAbstract: Multicast transmission and wireless caching are effective ways of reducing air and backhaul traffic load in wireless networks. This paper proposes to incorporate these two key ideas for content-centric transmission in a cloud radio access network (RAN) where multiple base stations (BSs) are connected to a central processor (CP) via finite-capacity backhaul links. Each BS has a cache with finite storage size and is equipped with multiple antennas. The BSs cooperatively transmit contents, either stored in the local cache or fetched from the CP, to multiple users in the network. Users requesting a same content form a multicast group and are served by a same cluster of BSs cooperatively using multicast beamforming. Assuming fixed cache placement, this paper investigates the joint design of multicast beamforming and content-centric BS clustering by formulating an optimization problem of minimizing the total network cost under the quality-of-service (QoS) constraints for each multicast group. The network cost involves both the transmission power and the backhaul cost. We model the backhaul cost using the mixed l(0)/l(2)-norm of beamforming vectors. To solve this non-convex problem, we first approximate it using the semidefinite relaxation (SDR) method and concave smooth functions. We then propose a difference of convex functions (DC) programming algorithm to obtain suboptimal solutions and show the connection of three smooth functions. Simulation results validate the advantage of multicasting and show the effects of different cache size and caching policies in cloud RAN.","Title: User-Centric Base Station Clustering And Sparse Beamforming For Cache-Enabled Cloud Ran\nYear: 2015\n\nAbstract: Cloud radio access network (Cloud RAN) is able to significantly improve the network capacity and energy efficiency through centralized processing of multiple distributed base stations (BSs). Yet it also places tremendous burden on backhaul links that connect these BSs. In this paper, we introduce a cache-enabled Cloud RAN, in which each BS is equipped with a local cache with limited storage capacity. If the content requested by a user is not cached at the serving BSs of the user, it will be distributed to the serving BSs via the backhaul links from the central processor (CP). We investigate the dynamic user-centric BS clustering and sparse beamforming by taking both channel condition and cache status into account. We formulate an optimization problem with the objective of minimizing the weighted sum of backhaul cost and transmit power cost subject to an individual signal-to-interference-and-noise ratio (SINR) constraint for each user. This problem is a mixed-integer non-linear programming (MINLP) problem. We apply the iterative reweighted l(1)-norm technique to find an approximate solution. Theoretical analysis also shows that all the BSs which cache the content requested by a user can always be included in the BS cluster of this user, regardless of their channel conditions. Based on this finding, we propose a cache-aware greedy selection BS clustering algorithm. Simulation results show that caching can greatly improve the tradeoff between backhaul capacity and transmit power. It is also demonstrated that popularity-aware caching is superior to random caching in Cloud RAN.","Title: Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel.\nYear: 2016\n\nAbstract: This letter studies the optimal degrees of freedom (DoF) region for the asymmetric three-user MIMO Y channel with antenna configuration (M 1 , M 2 , M 3 , N), where Mi is the number of antennas at user i and N is the number of antennas at the relay node. The converse is proved by using the cutset theorem and the genie-message approach. To prove the achievability, we divide the DoF tuples in the outer bound into two cases. For each case, we show that the DoF tuples are achievable by collectively utilizing antenna deactivation, pairwise signal alignment, and cyclic signal alignment techniques. This letter not only offers a complete characterization of DoF region for the considered channel model, but also provides a new and elegant achievability proof.","Title: Fundamental Tradeoff between Storage and Latency in Cache-Aided Wireless Interference Networks.\nYear: 2017\n\nAbstract: This paper studies the fundamental tradeoff between storage and latency in a general wireless interference network with caches equipped at all transmitters and receivers. The tradeoff is characterized by an information-theoretic metric, normalized delivery time (NDT), which is the worst case delivery time of the actual traffic load at a transmission rate specified by degrees of freedom of a given ...","Title: Communications, caching, and computing for content-centric mobile networks: part 1 [guest editorial].\nYear: 2016\n\nAbstract: The driving forces behind the exponential growth in mobile cellular network traffic have fundamentally shifted from the steady increase in demand for conventional \\\"connection-centric\\\" communications, such as phone calls and text messages, to the explosion of \\\"content- centric\\\" communications, such as video streaming and content sharing. The Cisco Visual Networking Index projects that video traffic will amount to 72 percent of global mobile data traffic by 2019. The mobile cellular network architectures of today are, however, still designed with a connection-centric communication mindset. Moreover, the myriad technological advances proposed for beyond fourth generation (4G) and 5G mobile networks still mostly focus on capacity increase, which is fundamentally constrained by the limited radio spectrum resources as well as the diminishing investment efficiency for operators, and therefore will always lag behind the growth rate of mobile traffic. It can be argued that the logjam in cellular networks cannot be addressed by improving connection capability alone, but instead must be tackled by fundamentally addressing the underlying ineffectiveness of the current communication architecture for massive content delivery.","Title: Compressed Channel Estimation With Position-Based ICI Elimination for High-Mobility SIMO-OFDM Systems.\nYear: 2016\n\nAbstract: Orthogonal frequency-division multiplexing (OFDM) is widely adopted for providing reliable and high-data-rate communication in high-speed train (HST) systems. However, with increasing train mobility, the resulting large Doppler shift introduces intercarrier interference (ICI) in OFDM systems and greatly degrades channel estimation accuracy. Therefore, it is necessary and important to investigate r...","Title: Linear Precoding For Cognitive Multiple Access Wiretap Channel With Finite-Alphabet Inputs\nYear: 2016\n\nAbstract: This paper investigates the linear precoder design for cognitive multiple-access wiretap channel (CMAC-WT), where two secondary-user transmitters (STs) communicate with one secondary-user receiver (SR) in the presence of an eavesdropper and subject to interference threshold constraints at primaryuser receivers (PRs). It designs linear precoders to maximize the ergodic secrecy sum rate for multiple-input multiple-output (MIMO) CMAC-WT under finite-alphabet inputs and statistical channel state information (CSI). For this non-convex problem, a two-layer algorithm is proposed by embedding the convex-concave procedure into an outer approximation framework. The key idea of this algorithm is to reformulate the approximated ergodic secrecy sum rate as a difference of convex (DC) functions, and then generate a sequence of simpler relaxed sets to approach the non-convex feasible set. In this way, near optimal precoding matrices are obtained by maximizing the approximated ergodic secrecy sum rate over a sequence of relaxed sets. Numerical results show that the proposed precoder design provides a significant performance gain over the Gaussian precoding method in the medium and high SNR regimes.","Title: On The Sum Dof Of The Asymmetric Four-User Mimo Y Channel\nYear: 2016\n\nAbstract: This work studies the sum degrees of freedom (DoF) of the asymmetric four-user MIMO Y channel, where each user i, for 1 <= i <= 4, is equipped with Mi antennas, and the relay is equipped with N antennas. By using the genie message approach, we derive that the sum DoF is upper bounded by min {Sigma(4)(i= 1) Mi(,) 2 Sigma(4)(i= 2) M-i, 2N, 2/7 Sigma(for all i for all j> i) max{N, M-i + M-j}, where M-1 >= M-2 >= M-3 >= M-4. Then, we show that the bound is tight under certain antenna constraints using signal alignment, generalized signal alignment, and antenna deactivation techniques.","Title: Embracing big data with compressive sensing: a green approach in industrial wireless networks.\nYear: 2016\n\nAbstract: New-generation industries heavily rely on big data to improve their efficiency. Such big data are commonly collected by smart nodes and transmitted to the cloud via wireless. Due to the limited size of smart node, the shortage of energy is always a critical issue, and the wireless data transmission is extremely a big power consumer. Aiming to reduce the energy consumption in wireless, this article introduces a potential breach from data redundancy. If redundant data are no longer collected, a large amount of wireless transmissions can be cancelled and their energy saved. Motivated by this breach, this article proposes a compressive-sensing-based collection framework to minimize the amount of collection while guaranteeing data quality. This framework is verified by experiments and extensive realtrace- driven simulations.","Title: Fundamental Storage-Latency Tradeoff in Cache-Aided MIMO Interference Networks.\nYear: 2017\n\nAbstract: Caching is an effective technique to improve user perceived experience for content delivery in wireless networks. Wireless caching differs from traditional web caching in that it can exploit the broadcast nature of wireless medium and hence, opportunistically change the network topologies. This paper studies a cache-aided MIMO interference network with three transmitters each equipped with M anten...","Title: A New Polar Coding Scheme for the Interference Channel.\nYear: 2016\n\nAbstract: We consider the problem of polar coding for the 2-user discrete memoryless interference channel (DM-IC) to achieve the Han-Kobayashi region, the best achievable rate region to date. Existing schemes are designed according to the original description of the Han-Kobayashi region, in which two deterministic functions that map auxiliary random variables to channel inputs are assumed to be known. Inspired by Chong et al.u0027s compact description of the Han-Kobayashi region, which uses joint distributions of random variables instead of deterministic functions, we find that the Han-Kobayashi region can be achieved in a simpler way. The original Han-Kobayashi strategy requires joint decoding of the intended senderu0027s private message and both sendersu0027 common messages at each receiver. In this paper, we show that all corner points of the Han-Kobayashi region can be achieved using partially joint decoders, i.e., each receiver only needs to jointly decode two of the three messages, either both sendersu0027 common messages, or the unintended senderu0027s common message and the intended senderu0027s private message. Based on this finding and enlightened by Goela et al.u0027s superposition polar coding schemes for the broadcast channels, we design two types of polar coding schemes, which can be seen as extensions of Carleialu0027s superposition coding scheme for the DM-IC with more powerful joint decoders, and show that every corner point can be achieved using one of the proposed schemes. The joint decoders and the corresponding code constructions are implemented using the 2-user multiple access channel (MAC) polarization technique based on Arikanu0027s monotone chain rule expansions, which has similar complexity to the single-user case. The chaining method which has already been widely used for constructing universal polar codes is adopted to solve the problem of alignment of polar indices.","Title: Optimization and Analysis of Probabilistic Caching in $N$-tier Heterogeneous Networks.\nYear: 2018\n\nAbstract: In this paper, we study the probabilistic caching for an N-tier wireless heterogeneous network (HetNet) using stochastic geometry. A general and tractable expression of the successful delivery probability (SDP) is first derived. We then optimize the caching probabilities for maximizing the SDP in the high signal-to-noise ratio regime. The problem is proved to be convex and solved efficiently. We n...","Title: Polar Coding for Block Fading Channels.\nYear: 2017\n\nAbstract: In this paper, we consider the problem of polar coding for block fading channels, with emphasis on those with instantaneous channel state information (CSI) at neither the transmitter nor the receiver. Our approach is to decompose a block fading channel of $T_c$ symbols per coherent interval into $T_c$ binary-input sub-channels in a capacity-preserving way, and design a polar code for each of them. For the case when instantaneous CSI is available at the receiver, a random interleaver can be used to enable joint encoding and decoding of all sub-channels so as to enhance the finite length performance. It is shown that our proposed schemes achieve the ergodic capacity of binary-input block fading channels under various CSI assumptions.","Title: Secure Polar Coding for the Two-Way Wiretap Channel.\nYear: 2018\n\nAbstract: In this paper, we consider the problem of polar coding for secure communications over the two-way wiretap channel, where two legitimate users communicate with each other simultaneously, while a passive eavesdropper overhears a combination of their exchanged signals. We design a low complexity polar coded cooperative jamming scheme that achieves the whole secrecy rate region of the general two-way wiretap channel under the strong secrecy criterion. The chaining method is used to make proper alignment of polar indices. The randomness required to be shared between two legitimate users is treated as a limited resource and we show that its rate can be made negligible by increasing the blocklength and the number of chained blocks. For the special case when the eavesdropper channel is degraded with respect to the legitimate ones, a simplified scheme is proposed which can simultaneously ensure reliability and weak secrecy within a single transmission block.","Title: Channel Measurement And Performance Of Multicast Beamforming In Campus Network\nYear: 2016\n\nAbstract: Multicast plays an important role in wireless networks to delivery a common message to multiple users simultaneously. Multicast beamforming can further boost the system performance by utilizing channel state information (CSI) at the base station (BS) equipped with multiple antennas. This paper provides a validation of multicast beamforming over actual channels measured in the Shanghai Jiao Tong University (SITU) campus wireless network, a FDD LTE network. We first build a receiver prototype using USRP N210 and LabV1EW for channel measurement. A single base station with 4 antennas and 3 single antenna receivers are considered. Based on the measured actual CSI, we then evaluate the performance of nmIticast beamforming under the quality of service (QoS) problem formulation, which is to minimize the transmit power consumption subject to an individual Signal to Noise Ratio (SNR) constraint for each user receiver. The Semi-Delinite Relaxation (SDR) approach is adopted to find an solution close to primitive solution. Experimental results demonstrate that multicast transmission using a single beamformer provides significant power gain over unicast transmission with multiple beamformers under the same QoS constraints in our considered campus network.","Title: A Storage-Latency Tradeoff Study for Cache-Aided MIMO Interference Networks.\nYear: 2016\n\nAbstract: Caching is an effective technique to improve user perceived experience for massive content delivery in wireless networks. An essential problem in cache-aided wireless networks is to find what and how much gain can be achieved by caching. This paper provides a study of the fundamental storage-latency tradeoff for a cache-aided MIMO interference network with 3 transmitters and 3 receivers and each node equipped with.. antennas. By using a newly proposed novel file splitting and caching strategy, the network topology during the content delivery phase is turned opportunistically to MIMO X channel, MIMO broadcast channel, MIMO multicast channel, or a hybrid form of these channels. Linear-precoding based interference management schemes such as interference alignment and neutralization over finite symbol extension are designed for these channels. We characterize the storage-latency tradeoff by fractional delivery time (FDT), a metric to evaluate the worst-case delivery time of the actual traffic load at a rate specified by the degrees of freedom (DoF) of the considered channel. The achievable FDT of our proposed scheme decreases piecewise linearly with the normalized cache sizes and is inversely proportional to the number of antennas. It is also shown that the achievable FDT is optimal at certain cache size regions and is within a multiplicative gap of 2 from the optimum at other regions.","Title: Linear Precoding for Fading Cognitive Multiple-Access Wiretap Channel With Finite-Alphabet Inputs\nYear: 2017\n\nAbstract: We investigate the fading cognitive multiple-access wiretap channel (CMAC-WT), in which two secondary-user transmitters (STs) send secure messages to a secondary-user receiver (SR) in the presence of an eavesdropper and subject to interference threshold constraints at multiple primary-user receivers (PRs). We design linear precoders to maximize the average secrecy sum rate for a multiple-input-mul...","Title: Modeling, Analysis, and Optimization of Coded Caching in Small-Cell Networks.\nYear: 2017\n\nAbstract: Coded caching is able to exploit accumulated cache size and hence superior to uncoded caching by distributing different fractions of a file in different nodes. This paper investigates coded caching in a large-scale small-cell network (SCN) where the locations of small base stations (SBSs) are modeled by stochastic geometry. We first propose a content delivery framework, where multiple SBSs that ca...","Title: Autonomous Relay for Millimeter-Wave Wireless Communications.\nYear: 2017\n\nAbstract: Millimeter-wave (mmWave) communication is the rising technology for next-generation wireless transmission. Benefited by its abundant bandwidth and short wavelength, mmWave is advanced in multi-gigabit transmittability and beamforming. In contrast, the short wavelength also makes mmWave easily blocked by obstacles. In order to bypass these obstacles, relays are widely needed in mmWave communications. Unmanned autonomous vehicles (UAVs), such as drones and self-driving robots, enable the mobile relays in real applications. Nevertheless, it is challenging for a UAV to find its optimal relay location automatically. On the one hand, it is difficult to find the location accurately due to the complex and dynamic wireless environment; on the other hand, most applications require the relay to forward data immediately, so the autonomous process should be fast. To tackle this challenge, we propose a novel method AutoRelay specialized for mmWave communications. In AutoRelay, the UAV samples the link qualities of mmWave beams while moving. Based on the real-time sampling, the UAV gradually adjusts its path to approach the optimal location by leveraging compressive sensing theory to estimate the link qualities in candidate space, which increases the accuracy and save the time. Performance results demonstrate that AutoRelay outperforms existing methods in achieving an accurate and efficient relay strategy.","Title: Low-Complexity Hybrid Analog/Digital Beamforming For Multicast Transmission In Mmwave Systems\nYear: 2017\n\nAbstract: This paper studies multi-group multicast beamforming with a hybrid large-scale antenna array in millimeter wave (mmWave) communication systems. A low-complexity hybrid structure is adopted, where each RF chain is only connected to part of the antenna elements. We formulate a hybrid analog and digital beamforming design problem for multi-group multicast transmission with the objective of minimizing the total transmit power at the base station, subject to an individual signal-to-interference-plus-noise ratio constraint for each multicast group. The problem is very challenging and its global optimal solution is difficult to obtain. We first adopt alternating minimization method to design the analog and digital beamformer alternatively. Then we solve each of the analog and digital subproblems through solving a sequence of convex problems via concave-convex procedure (CCP). Each convex CCP subproblem is reformulated as a novel alternating direction method of multipliers (ADMM) form. Our ADMM reformulation enables that each updating step can be decomposed into multiple subproblems with much smaller size, which can be solved optimally in parallel with closed-form expressions. Simulation results show that our algorithm can achieve favorable performance with very low complexity compared with the state-of-art methods.","Title: Stochastic Modeling, Analysis And Optimization Of Coded Caching In Small-Cell Networks\nYear: 2017\n\nAbstract: Coded caching is able to exploit accumulated cache size in a wireless network by storing fractions of files in each node. In this work, we model, analyze, and optimize coded caching in cache-enabled small-cell networks (SCNs). We first propose a content delivery framework for coded caching, where multiple small base stations (SBSs) that cache different coded packets of a desired file transmit simultaneously upon a user request and the packets are decoded using successive interference cancellation (SIC)-based receiver. A closed-form expression for the successful transmission probability with SIC receiver in the high signal-to-noise ratio (SNR) region is derived by using stochastic geometry. We next optimize the cache placement to maximize the average fraction of offloaded traffic by the cache-enabled SBSs. The coded cache placement problem is formulated as a multiple-choice knapsack problem (MCKP). By exploiting the analytic properties of the average traffic offload fraction, we propose a greedy but optimal algorithm. Numerical results show our proposed coded caching scheme facilitated by simultaneous transmission and SIC-based receiving significantly outperforms uncoded caching. In addition, the coded caching only needs to split each file into a small number of fragments to approach an ideal performance.","Title: Cooperative caching for spectrum access in cognitive radio networks\nYear: 2017\n\nAbstract: In this paper, we investigate cooperative caching for spectrum access in cognitive radio networks. By cooperative caching, we mean that the unlicensed secondary base station (SBS) can cache certain primary contents to serve primary users, in exchange for the opportunities to access the licensed spectrum. We consider the joint optimization of caching and scheduling of the SBS to maximize the weighted average number of satisfied secondary requests under the average available time constraint and the cache capacity constraint. This problem is a mixed-integer bilinear programming, which is challenging in general. By exploring the special structure of the problem, we first show that the optimal caching satisfies a cache-split structure and the optimal scheduling satisfies a rate-ratio structure. Then, based on these optimality properties, we transform the original problem into a simplified joint cache splitting and SU partitioning optimization problem, and propose an efficient algorithm to solve it optimally. Moreover, we investigate the impacts of the primary and secondary content popularity distributions on the system performance. Numerical results verify the theoretical analysis and provide some counter-intuitive insights.","Title: Design of Contract-Based Trading Mechanism for a Small-Cell Caching System.\nYear: 2017\n\nAbstract: Recently, content-aware-enabled distributed caching relying on local small-cell base stations (SBSs), namely, smallcell caching, has been intensively studied for reducing transmission latency as well as alleviating the traffic load over backhaul channels. In this paper, we consider a commercialized small-cell caching system consisting of a network service provider (NSP), several content providers ...","Title: Analysis and Optimization of Probabilistic Caching in Multi-Antenna Small-Cell Networks.\nYear: 2017\n\nAbstract: Previous works on cache-enabled small-cell networks (SCNs) with probabilistic caching often assume that each user is connected to the nearest small base station (SBS) among all that have cached its desired content. The user may, however, suffer strong interference from other SBSs which do not cache the desired content but are geographically closer. In this work, we investigate this issue by deploying multiple antennas at each SBS. We first propose a user-centric SBS clustering model where each user chooses its serving SBS only from a cluster of.. nearest SBSs with.. being a fixed cluster size. Two beamforming schemes are considered. One is coordinated beamforming, where each SBS uses zero-forcing (ZF) beamformer to null out the interference within the coordination cluster. The other is uncoordinated beamforming, where each SBS simply applies matched-filter (MF) beamformer. Using tools from stochastic geometry, we obtain tractable expressions for the successful transmission probability (STP) of a typical user for both cases in the high signal-tonoise ratio (SNR) region. Tight approximations in closed-form expressions are also obtained. We then formulate and solve the optimal probabilistic caching problem to maximize the STP. Numerical results reveal interesting insights on the choices of ZF and MF beamforming in multi-antenna cache-enabled SCNs.","Title: Content Delivery in MIMO Broadcast Channels with Decentralized Coded Caching.\nYear: 2017\n\nAbstract: Caching at the wireless edge is an effective way to trade the scarce communication bandwidth with the more sustainable storage size through traffic time shifting. Multiple-input multiple-output (MIMO), on the other hand, can bring spatial multiplexing gain in wireless channels. This work is to investigate the combined effect of MIMO and caching in a three-user cache-aided MIMO broadcast channel, where the base station is equipped with.. antennas and each user is equipped with.. antennas. Decentralized coded caching is adopted in this paper, which converts the content delivery phase to a transmission problem in a broadcast channel with general message sets. We first derive an achievable degrees of freedom (DoF) region of the three-user MIMO broadcast channel with general message sets. Based on this region, we then obtain an achievable normalized delivery time (NDT), which illustrates the spatial multiplexing gain of MIMO through simultaneous transmission of multiple multicast messages intended to different user sets. It is shown that the achievable NDT is optimal at certain cases and is within a multiplicative gap of 3 from the optimum at other cases.","Title: Backhaul-Constrained Joint Beamforming for Non-Orthogonal Multicast and Unicast Transmission.\nYear: 2017\n\nAbstract: The demand for providing multicast services in emerging cellular networks is increasing. This paper proposes a non-orthogonal transmission framework based on layered-division multiplexing (LDM) to incorporate multicast and unicast services into cellular networks with limited-capacity backhaul. We adopt a two-layer LDM structure where the first layer is intended for multicast services, the second layer is for unicast services, and the two layers are superposed with different beamformers and decoded by each user receiver using successive interference cancellation. To optimize the non-orthogonal transmission, we formulate a joint multicast and unicast beamforming design problem with adaptive base station (BS) clustering that aims to maximize the weighted sum of multicast rate and unicast rate under peak power constraints and peak backhaul constraints on each BS. The problem is a sparse optimization problem and NP-hard. By means of smoothed l(0)-norm approximation and novel algebraic operations, we transform it into a difference of convex (DC) programming, which is solved using convex-concave procedure (CCP) with guaranteed convergence. Simulation results demonstrate the superiority of the proposed algorithm, especially when the backhaul constraint is not too stringent. Results also show that the proposed LDM-based non-orthogonal scheme can achieve a much larger multicast-unicast rate region than orthogonal schemes.","Title: On the DoF Region for the Asymmetric MIMO Two-Way X Relay Channel.\nYear: 2018\n\nAbstract: In this paper, we study the degrees of freedom (DoF) region for the multiple-input multiple-output two-way X relay channel with asymmetric antenna setting. In this channel model, there are two groups of source nodes, each group contains two source nodes, every source node in one group exchanges independent messages with every source node in another group via a common relay node, and each node has ...","Title: Joint Base Station Clustering and Beamforming for Non-Orthogonal Multicast and Unicast Transmission with Backhaul Constraints.\nYear: 2018\n\nAbstract: The demand for providing multicast services in cellular networks is continuously and fastly increasing. In this paper, we propose a non-orthogonal transmission framework based on layered-division multiplexing (LDM) to support multicast and unicast services concurrently in cooperative multi-cell cellular networks with a limited backhaul capacity. We adopt a two-layer LDM structure where the first l...","Title: Robust design of hybrid multicast beamforming with phase error in mmWave systems\nYear: 2017\n\nAbstract: This paper studies the robust beamforming design for multi-group multicast transmission with a hybrid analog and digital structure in millimeter wave (mmWave) communication systems. Unlike the conventional additive error model, we consider a novel multiplicative phase error model which is more suitable for capturing the channel uncertainty in mmWave systems. We adopt a partially-connected hybrid structure where each radio frequency (RF) chain is connected to an exclusive subset of antenna elements at the base station. The robust design problem is formulated to minimize the total transmit power while satisfying the outage constraint for each user's signal-to-interference-plus-noise ratio (SINR). We first utilize the alternating minimization method to optimize the analog and digital beamformers alternatively. Each of these two subproblems is then solved approximately by using the second-order Taylor expansion together with the Bernstein-type inequality. Simulation results show that the approximation is quite safe and the outage constraint can be well satisfied. It is also shown that the power performance of the proposed robust design is within 1dB close to the ideal case when the standard derivation of the channel phase error is within 5.7°.","Title: Communications, Caching and Computing for Mobile Virtual Reality: Modeling and Tradeoff.\nYear: 2018\n\nAbstract: Virtual reality (VR) over wireless is emerging as an important use case of 5G networks. Fully-immersive VR experience requires the wireless delivery of huge data at ultra-low latency, thus leading to ultra-high transmission rate requirement for wireless communications. This challenge can be largely addressed by the recent network architecture known as mobile edge computing (MEC) network, which enables caching and computing capabilities at the edge of wireless networks. This paper presents a novel MEC-based mobile VR delivery framework that is able to cache parts of the field of views (FOVs) in advance and compute certain post-processing procedures on demand at the mobile VR device. To minimize the average required transmission rate, we formulate the joint caching and computing optimization problem to determine which FOVs to cache, whether to cache them in 2D or 3D as well as which FOVs to compute at the mobile device under cache size, average power consumption as well as latency constraints. When FOVs are homogeneous, we obtain a closed-form expression for the optimal joint policy which reveals interesting communications-caching-computing tradeoffs. When FOVs are heterogeneous, we obtain a local optima of the problem by transforming it into a linearly constrained indefinite quadratic problem and then applying concave convex procedure. Numerical results demonstrate the proposed mobile VR delivery framework can significantly reduce communication bandwidth while meeting low latency requirement.","Title: Fitness-Aware Coded Multicasting for Decentralized Caching With Finite File Packetization.\nYear: 2018\n\nAbstract: Coded caching has been shown to significantly reduce traffic load for wireless content delivery by creating coded multicasting opportunities. However, its order-optimal memory-load tradeoff performance requires the file size to go to infinity or grow exponentially with the number of users. This letter introduces a new delivery scheme for decentralized cache placement in practical settings with fin...","Title: User-Centric Joint Access-Backhaul Design for Full-Duplex Self-Backhauled Wireless Networks.\nYear: 2018\n\nAbstract: Full-duplex self-backhauling is promising to provide cost-effective and flexible backhaul connectivity for ultra-dense wireless networks, but also poses a great challenge to resource management between the access and backhaul links. In this paper, we propose a user-centric joint access-backhaul transmission framework for full-duplex self-backhauled wireless networks. In the access link, user-centric clustering is adopted so that each user is cooperatively served by multiple small base stations (SBSs). In the backhaul link, user-centric multicast transmission is proposed so that each user’s message is treated as a common message and multicast to its serving SBS cluster. We first formulate an optimization problem to maximize the network weighted sum rate through joint access-backhaul beamforming and SBS clustering when global channel state information (CSI) is available. This problem is efficiently solved via the successive lower-bound maximization approach with a novel approximate objective function and the iterative link removal technique. We then extend the study to the stochastic joint access-backhaul beamforming optimization with partial CSI. Simulation results demonstrate the effectiveness of the proposed algorithms for both full CSI and partial CSI scenarios. They also show that the transmission design with partial CSI can greatly reduce the CSI overhead with little performance degradation.","Title: User-Centric Joint Access-Backhaul Design for Full-Duplex Self-Backhauled Cooperative Networks.\nYear: 2018\n\nAbstract: In-band full-duplex (IBFD) self-backhauling is promising to provide cost-effective and flexible backhaul connectivity in ultra-dense wireless networks. In this paper, we propose a user-centric joint access-backhaul transmission framework for performance optimization in IBFD-enabled self-backhauled cooperative wireless networks. In the access link, user-centric clustering is adopted so that each user is cooperatively served by a cluster of small base stations (SBSs) via joint beamforming. In the backhaul link, user-centric multicast transmission is proposed so that the macro base station (MBS) treats each user's data as a multicast message and sends it to its serving SBS cluster. We formulate an optimization problem to maximize the endto-end weighted sum rate of all users under power constraints through joint design of multicast beamforming in the backhaul link as well as SBS clustering and beamforming in the access link. We first tackle the joint access-backhaul beamforming problem under given SBS clustering by transforming it into a manifold optimization problem, for which a stationary solution is obtained using the Riemannian optimization technique. We then develop a heuristic algorithm to determine the SBS clustering. Simulation results demonstrate the effectiveness of the proposed algorithms.","Title: Exploiting Computation Replication in Multi-User Multi-Server Mobile Edge Computing Networks.\nYear: 2018\n\nAbstract: In mobile edge computing (MEC) systems, mobile devices can offload their computation-intensive tasks to edge servers to save energy and shorten latency. However, the extra latency for downloading the computed results back may degrade the benefits of computation offloading if the downlink channel suffers severe fading and interference. In this work, we exploit computation replication in task offloading to reduce the download latency in multi-user multi-server MEC networks. The main idea is to partition the task generated by each user into multiple subtasks, and offload each subtask to a set of MEC servers via the uplink channel for repeated execution. The duplication of computation results on multiple servers thus enables data-sharing based transmission cooperation to send the results back to users. Next, we adopt an asymptotic total latency that accounts the uploading, computing and results downloading phases as the performance metric to capture the tradeoff between the increased computation load and the reduced communication time. We formulate a linear programming problem to optimize the task partition ratios for minimizing the total latency. We show that there exists an optimal degrees of replication (the number of MEC servers to compute the same subtask) and an associated task partition strategy for optimal latency performance. Our finding reveals great advantage of computation replication for latency reduction in multi-server MEC networks where the output data size of each computation task is non-negligible.","Title: Modeling and Trade-off for Mobile Communication, Computing and Caching Networks.\nYear: 2018\n\nAbstract: This paper considers a new mobile edge computing (MEC) model where the MEC server has the input and output data of all computation tasks and communicates with multiple caching-and-computing-enabled mobile devices via a shared wireless link. Each mobile device can pre-store the input or output data of a task and also execute a task locally. We aim to investigate the impact of local caching and computing at mobile devices as well as content-centric multicast transmission on the saving of required bandwidth on the wireless link. To this end, we first formulate a joint caching and computing decision optimization problem to minimize the required transmission bandwidth subject to latency, caching and energy constraints at each mobile device in the general case. The joint policy optimization problem is shown to be NP-hard. Based on equivalent transformation and exact penalization of the problem, a stationary point is obtained via concave convex procedure. In the special case where all the computation tasks are symmetric and user requests are uniform, we obtain the closed-form expressions for the local caching gain, local computing gain, and multicasting gain. Our results indicate that exploiting the computing and caching resources at mobile devices can provide significant bandwidth savings.","Title: Collaborative Multi-Agent Reinforcement Learning of Caching Optimization in Small-Cell Networks.\nYear: 2018\n\nAbstract: Previous works on learning-based caching problems often only focus on a single base station (BS) scenario. For works considering multiple BSs, the coordination among BSs only exists in the cache placement phase after the learning phase that each BS estimates the file popularity independently. In this work, we investigate the cache strategy design problem in small cell networks (SCNs) with multiple small base stations (SBSs) when user preferences are unknown. We model this multi-agent decision making problem in a multi-armed bandit (MAB) perspective. We first tackle this problem with the centralized MAB algorithm and distributed multi-agent MAB (MAMAB) algorithm. For the centralized algorithm, it considers the coordinations among SBSs but the computational complexity grows exponentially with the number of SBSs. For the distributed one, the computational complexity grows linearly with the number of SBSs but the coordinations among SBSs are totally ignored. To take both coordination among SBSs and computational complexity into account, we propose a collaborative MAMAB algorithm to learn the cache strategy directly, rather than learning the user preferences. The simulation results show that the collaborative MAMAB approaches the performance of the greedy algorithm when the user preferences are perfectly known.","Title: A Channel Sensing Based Design For Lte In Unlicensed Bands\nYear: 2015\n\nAbstract: With the exponential growth of wireless data traffic and the increasing scarcity of licensed spectrum, mobile network operators intend to use the unlicensed spectrum, such as the Industrial, Scientific and Medical (ISM) bands and TV white space, to offload their traffic. In the future, it is very likely that two of the most prominent wireless technologies, Long Term Evolution (LTE) and WiFi, will coexist on the same unlicensed bands. Existing simulation results show that LTE is slightly impacted by such coexistence while WiFi is severely hampered by LTE transmissions. In order to realize a harmonious LTE/WiFi coexistence, we propose two channel sensing schemes for LTE in unlicensed bands, i.e., periodic sensing and persistent sensing. Simulation results show that the proposed channel sensing schemes can provide a reasonable tradeoff between LTE and WiFi when they coexist with each other.","Title: ADMM-Based Fast Algorithm for Multi-Group Multicast Beamforming in Large-Scale Wireless Systems.\nYear: 2017\n\nAbstract: Multi-group multicast beamforming in wireless systems with large antenna arrays and massive audience is investigated in this paper. Multicast beamforming design is a well-known non-convex quadratically constrained quadratic programming (QCQP) problem. A conventional method to tackle this problem is to approximate it as a semi-definite programming problem via semi-definite relaxation, whose perform...","Title: Multicast Beamforming Design in Multicell Networks With Successive Group Decoding.\nYear: 2017\n\nAbstract: We consider a generic problem of multicast beamforming design in multicell networks where each base station (BS) has multiple independent messages to multicast and each user intends to decode an arbitrary subset of messages sent from all BSs using successive group decoding (SGD). We first formulate the total transmit power minimization problem subject to the constraints that a target rate vector i...","Title: Cache-Aided Interference Management in Partially Connected Wireless Networks.\nYear: 2017\n\nAbstract: Cache-aided communication is emerging as a new topic in wireless networks. Previous works have shown that caching in interference networks can change the interference topology by changing the information flow and hence facilitate advanced interference management. This paper studies the gain of caching in partially connected interference networks where each receiver can only communicate with a subset of transmitters. The performance is characterized by an information-theoretic metric, normalized delivery time (NDT). We obtain an order-optimal NDT for the (K + L - 1) x K partially connected linear interference network with any number of receivers K, any receiver connectivity L <= K, and with caches equipped at all transmitters and receivers. The cache placement phase adopts a file splitting strategy tailor-made for the partial receiver connectivity. Via the aid of virtual receivers, the proposed delivery strategy exploits coded multicasting gain by XOR combining and transmitter coordination gain by interference alignment. In the special case when L is a divisor of K, our NDT results are directly applicable to K x K partially connected circular interference networks.","Title: Polar Coding Strategies for the Interference Channel With Partial-Joint Decoding\nYear: 2019\n\nAbstract: Existing polar coding schemes for the two-user interference channel follow the original idea of Han and Kobayashi, in which component messages are encoded independently and then mapped by some deterministic functions (i.e., homogeneous superposition coding). In this paper, we propose a new polar coding scheme for the interference channel based on the heterogeneous superposition coding approach of Chong, Motani, and Garg. We prove that fully joint decoding (the receivers simultaneously decode both senders’ common messages and the intended sender’s private message) in the Han–Kobayashi strategy can be simplified to two types of partial-joint decoding, which are friendly to polar coding with practical decoding algorithms. The proposed coding scheme requires less auxiliary random variables and no deterministic functions and can be efficiently constructed. Furthermore, we extend this result to interference networks and show that partial-joint decoding is a general method for designing heterogeneous superposition polar coding schemes in interference networks.","Title: Fundamental Limits Of Decentralized Caching In Fog-Rans With Wireless Fronthaul\nYear: 2018\n\nAbstract: This paper aims to characterize the synergy of distributed caching and wireless fronthaul in a fog radio access network (Fog- RAN) where all edge nodes (ENs) and user equipments (UEs) have a local cache and store contents independently at random. The network operates in two phases, a file-splitting based decentralized cache placement phase and a fronthaul-aided content delivery phase. We adopt normalized delivery time (NDT) to characterize the asymptotic latency performance with respect to cache size and fronthaul capacity. Both an achievable upper bound and a theoretical lower bound of NDT are obtained, and their multiplicative gap is within 12. In the proposed delivery scheme, we utilize the fronthaul link, by exploiting coded multicasting, to fetch both non-cached and cached contents to boost EN cooperation in the access link. In particular, to fetch contents already cached at ENs, an additional layer of coded multicasting is added on the coded messages desired by UEs in the fronthaul link. Our analysis shows that the proposed delivery scheme can balance the delivery latency between the fronthaul link and access link, and is approximately optimum under decentralized caching.","Title: The Role of Caching in Future Communication Systems and Networks.\nYear: 2018\n\nAbstract: This paper has the following ambitious goal: to convince the reader that content caching is an exciting research topic for the future communication systems and networks. Caching has been studied for more than 40 years, and has recently received increased attention from industry and academia. Novel caching techniques promise to push the network performance to unprecedented limits, but also pose sig...","Title: Energy and Latency Control for Edge Computing in Dense V2X Networks.\nYear: 2018\n\nAbstract: This study focuses on edge computing in dense millimeter wave vehicle-to-everything (V2X) networks. A control problem is formulated to minimize the energy consumption under delay constraint resulting from vehicle mobility. A tractable algorithm is proposed to solve this problem by optimizing the offloaded computing tasks and transmit power of vehicles and road side units. The proposed dynamic solution can well coordinate the interference without requiring global channel state information, and makes a tradeoff between energy consumption and task computing latency.","Title: Content Caching and Delivery in Wireless Radio Access Networks.\nYear: 2019\n\nAbstract: Today’s mobile data traffic is dominated by content-oriented traffic. Caching popular contents at the network edge can alleviate network congestion and reduce content delivery latency. This paper provides a comprehensive and unified study of caching and delivery techniques in wireless radio access networks (RANs) with caches at all edge nodes (ENs) and user equipments (UEs). Three cache-aided RAN architectures are considered: RANs without fronthaul, with dedicated fronthaul, and with wireless fronthaul. It first reviews in a tutorial nature how caching facilitates interference management in these networks by enabling interference cancelation (IC), zero-forcing (ZF), and interference alignment (IA). Then, two new delivery schemes are presented. One is for RANs with dedicated fronthaul, which considers centralized cache placement at the ENs but both centralized and decentralized placement at the UEs. This scheme combines IA, ZF, and IC together with soft-transfer fronthauling. The other is for RANs with wireless fronthaul, which considers decentralized cache placement at all nodes. It leverages the broadcast nature of wireless fronthaul to fetch not only uncached but also cached contents to boost transmission cooperation among the ENs. The numerical results show that both schemes outperform existing results for a wide range of system parameters, thanks to the various caching gains obtained opportunistically.","Title: Exploiting Computation Replication for Mobile Edge Computing: A Fundamental Computation-Communication Tradeoff Study.\nYear: 2019\n\nAbstract: Existing works on task offloading in mobile edge computing (MEC) networks often assume a task is executed once at a single edge node (EN). Downloading the computed result from the EN back to the mobile user may suffer long delay if the downlink channel experiences strong interference or deep fading. This paper exploits the idea of computation replication in MEC networks to speed up the downloading phase. Computation replication allows each user to offload its task to multiple ENs for repetitive execution so as to create multiple copies of the computed result at different ENs which can then enable transmission cooperation and hence reduce the communication latency for result downloading. Yet, computation replication may also increase the communication latency for task uploading, despite the obvious increase in computation load. The main contribution of this work is to characterize asymptotically an order-optimal upload-download communication latency pair for a given computation load in a multi-user multi-server MEC network. Analysis shows when the computation load increases within a certain range, the downloading time decreases in an inversely proportional way if it is binary offloading or decreases linearly if it is partial offloading, both at the expense of linear increase in the uploading time.","Title: Joint User Activity Detection and Channel Estimation for Temporal-Correlated Massive Access\nYear: 2021\n\nAbstract: This paper studies the temporal-correlated massive access system where a large number of devices communicate with the base station sporadically and continue transmitting data in the adjacent frames in high probability when being active. By exploiting the sparsity and the temporal correlations of the user activities, the joint user activity detection and channel estimation (JUADCE) problem in multiple consecutive frames can be formulated as a dynamic compressed sensing (DCS) problem. Specifically, we formulate a probabilistic model that accounts the statistics of channels and characterizes the evolutions of the user activities by a steady Markov chain. The hybrid generalized approximate message passing (HyGAMP) framework is leveraged to develop a computationally efficient algorithm named HyGAMP-DCS to solve the JUADCE problem. The HyGAMP-DCS algorithm performs channel estimation in the GAMP part and soft user activity information update in the MP part, then exchanges intrinsic information between these two parts for performance enhancement. Simulation results demonstrate that the proposed algorithm can significantly outperform the conventional DCS-based algorithms and the GAMP algorithm which ignores the temporal correlations.","Title: Sum-Rate-Distortion Function For Indirect Multiterminal Source Coding In Federated Learning\nYear: 2021\n\nAbstract: One of the main focus in federated learning (FL) is the communication efficiency since a large number of participating edge devices send their updates to the edge server at each round of the model training. Existing works reconstruct each model update from edge devices and implicitly assume that the local model updates are independent over edge devices. In FL, however, the model update is an indirect multi-terminal source coding problem, also called as the CEO problem where each edge device cannot observe directly the gradient that is to be reconstructed at the decoder, but is rather provided only with a noisy version. The existing works do not leverage the redundancy in the information transmitted by different edges. This paper studies the rate region for the indirect multiterminal source coding problem in FL. The goal is to obtain the minimum achievable rate at a particular upper bound of gradient variance. We obtain the rate region for the quadratic vector Gaussian CEO problem under unbiased estimator and derive an explicit formula of the sum-rate-distortion function in the special case where gradient are identical over edge device and dimension. Finally, we analyse communication efficiency of convex Minibatched SGD and non-convex Minibatched SGD based on the sum-rate-distortion function, respectively.","Title: Resource Allocation for Deterministic Delay in Wireless Control Networks\nYear: 2021\n\nAbstract: Meeting the high requirements of deterministic transmission in wireless control systems is very challenging, but also very important. In order to improve the determinacy of wireless short packet transmission, we optimize the communication resource required for multi-sensors in the wireless control system in this letter. In particular, we derive the probability of the transmission delay falling wit...","Title: Adaptive Clustering-Based Model Aggregation for Federated Learning with Imbalanced Data\nYear: 2021\n\nAbstract: This paper studies the data imbalance issue in federated learning. We propose a new model aggregation method based on adaptive clustering, called weighted clustered federated learning (CFL). At each round of model aggregation, we first cluster the participating edge devices based on the cosine similarity of their local gradients, where the similarity threshold can adapt to the time varying diverge...","Title: An Adaptive Distributed Source Coding Design for Distributed Learning\nYear: 2021\n\nAbstract: A major bottleneck in distributed learning is the communication overhead of exchanging intermediate model update parameters between the worker nodes and the parameter server. Existing works reconstruct each model update from worker nodes and implicitly assume that the local model updates are independent over worker nodes. In distributed learning, however, the model update is an indirect multi-term...","Title: Coded Caching With Device Computing in Mobile Edge Computing Systems\nYear: 2021\n\nAbstract: Edge caching and computing have been regarded as an efficient approach to tackle the wireless spectrum crunch problem. In this paper, we design a general coded caching with device computing strategy for computational tasks, e.g., virtual reality (VR) rendering, to minimize the average transmission bandwidth under the quality of service guarantee. Because both coded data and stored data can be the ...","Title: Joint Design of Hybrid Beamforming and Reflection Coefficients in RIS-Aided mmWave MIMO Systems\nYear: 2022\n\nAbstract: This paper considers a reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) downlink communication system where hybrid analog-digital beamforming is employed at the base station (BS). We formulate a power minimization problem by jointly optimizing hybrid beamforming at the BS and the response matrix at the RIS, under the signal-to-interference-plus-noise ratio (SINR) constraints...","Title: A Learning Based Branch-and-Bound Algorithm for Single-Group Multicast Beamforming\nYear: 2021\n\nAbstract: Consider the single-group multicast beamforming problem in wireless systems, where a multi-antenna transmitter has a common message intended to a group of users. The problem is known be non-convex and NP-hard except in very few special cases. Traditional optimization-based algorithms either obtain sub-optimal solutions or take exponential complexity to reach the optimum. In this paper, we propose a learning based branch-and-bound (LBB) algorithm to find a near-optimal solution of the quality-of-service (QoS)-constrained multicast beamforming problem with affordable computational complexity. LBB regards the search procedure of the argument-cut based branch-and-bound (AC-BB) algorithm as a sequential decision problem in a binary tree and learns the optimal pruning policy via supervised learning. We propose to apply ensemble learning to train multiple classifiers and then combine them to achieve better performance. To tackle the imbalanced issue, we propose an undersampling-supervised learning method to sample several balanced subsets and train a classifier on each of them. We also show that the computational complexity of LBB is determined by the depth of the binary tree and give its expression in the worst case. Numerical results show that LBB runs significantly faster than AC-BB while achieving nearly the same optimal performance.","Title: Millidegree-Level Direction-of-Arrival Estimation and Tracking for Terahertz Ultra-Massive MIMO Systems\nYear: 2022\n\nAbstract: Terahertz (0.1-10 THz) wireless communications are expected to meet 100+ Gbps data rates for 6G communications. Being able to combat the distance limitation with reduced hardware complexity, ultra-massive multiple-input multiple-output (UM-MIMO) systems with hybrid dynamic array-of-subarrays (DAoSA) beamforming are a promising technology for THz wireless communications. However, fundamental challenges in THz DAoSA systems include millidegree-level three-dimensional direction-of-arrival (DoA) estimation and millisecond-level beam tracking with reduced pilot overhead. To address these challenges, an off-grid subspace-based DAoSA-MUSIC and a deep convolutional neural network (DCNN) methods are proposed for DoA estimation. Furthermore, by exploiting the temporal correlations of the channel variation, an augmented DAoSA-MUSIC-T and a convolutional long short-term memory (ConvLSTM) solutions are further developed to realize DoA tracking. Extensive simulations and comparisons on the proposed subspace- and deep-learning-based algorithms are conducted. Results show that both DAoSA-MUSIC and DCNN achieve super-resolution DoA estimation and outperform existing solutions, while DCNN performs better than DAoSA-MUSIC at a high signal-to-noise ratio. Moreover, DAoSA-MUSIC-T and ConvLSTM can capture fleeting DoA variation with an accuracy of 0.1° within milliseconds, and reduce 50% pilot overhead. Compared to DAoSA-MUSIC-T, ConvLSTM can tolerate large angle variation and remain robust over a long duration.","Title: Double-Sided Information Aided Temporal-Correlated Massive Access\nYear: 2022\n\nAbstract: This letter considers temporal-correlated massive access, where each device, once activated, is likely to transmit continuously over several consecutive frames. Motivated by that the device activity at each frame is correlated to not only its previous frame but also its next frame, we propose a double-sided information (DSI) aided joint activity detection and channel estimation algorithm based on the approximate message passing (AMP) framework. The DSI is extracted from the estimation results in a sliding window that contains the target detection frame and its previous and next frames. The proposed algorithm demonstrates superior performance over the state-of-the-art methods.","Title: Editorial Issue on “Information Theoretic Foundations of Future Communication Systems”\nYear: 2022\n\nAbstract: Information theory, starting with Shannon’s groundbreaking work, has fundamentally shaped the way communication systems are designed and operated. Information theoretic principles form the underpinnings of modern communication networks. This issue explores how new advances in information theory can impact future communication systems. Several papers address issues at the heart of next generation w...","Title: Learning-Based Branch-and-Bound for Non-Convex Complex Modulus Constrained Problems With Applications in Wireless Communications\nYear: 2022\n\nAbstract: We consider a class of non-convex complex modulus constrained problems (CMCPs), which has many important applications in signal processing for wireless communications, including multicast beamforming and multi-input multi-output detection. Due to the non-convex constraints, traditional optimization-based algorithms either obtain sub-optimal solutions or take exponential complexity to reach the optimum. In this paper, we propose a learning based branch-and-bound (LBB) algorithm for solving the considered CMCPs. LBB regards the search procedure of the global optimal argument-cut based branch-and-bound (AC-BB) algorithm as a sequential decision problem in a binary tree and learns the optimal pruning policy via supervised learning. We first propose to apply ensemble learning to train multiple classifiers and then combine them to achieve better performance. To tackle the imbalanced issue, we propose an undersampling-supervised learning method to sample several balanced subsets and train a classifier on each of them. We also show that the computational complexity of LBB is determined by the depth of the binary tree and give its expression in the worst case. Finally, we validate the proposed LBB with two classic problems in wireless communications, i.e., multicast beamforming and MIMO detection. Numerical results show that LBB runs significantly faster than AC-BB while achieving nearly the same optimal performance.","Title: Characteristics of Channel Eigenvalues and Mutual Coupling Effects for Holographic Reconfigurable Intelligent Surfaces\nYear: 2022\n\nAbstract: As a prospective key technology for the next-generation wireless communications, reconfigurable intelligent surfaces (RISs) have gained tremendous research interest in both the academia and industry in recent years. Only limited knowledge, however, has been obtained about the channel eigenvalue characteristics and spatial degrees of freedom (DoF) of systems containing RISs, especially when mutual coupling (MC) is present between the array elements. In this paper, we focus on the small-scale spatial correlation and eigenvalue properties excluding and including MC effects, for RISs with a quasi-continuous aperture (i.e., holographic RISs). Specifically, asymptotic behaviors of far-field and near-field eigenvalues of the spatial correlation matrix of holographic RISs without MC are first investigated, where the counter-intuitive observation of a lower DoF with more elements is explained by leveraging the power spectrum of the spatial correlation function. Second, a novel metric is proposed to quantify the inter-element correlation or coupling strength in RISs and ordinary antenna arrays. Furthermore, in-depth analysis is performed regarding the MC effects on array gain, effective spatial correlation, and eigenvalue architectures for a variety of element intervals when a holographic RIS works in the radiation and reception mode, respectively. The analysis and numerical results demonstrate that a considerable amount of the eigenvalues of the spatial correlation matrix correspond to evanescent waves that are promising for near-field communication and sensing. More importantly, holographic RISs can potentially reach an array gain conspicuously larger than conventional arrays by exploiting MC, and MC has discrepant impacts on the effective spatial correlation and eigenvalue structures at the transmitter and receiver.","Title: Computation Capacity Enhancement by Joint UAV and RIS Design in IoT\nYear: 2022\n\nAbstract: Mobile-edge computing (MEC) networks are facing limited coverage and harsh wireless transmission environments that severely hinder the computation capacity of the Internet-of-Things (IoT) devices. To overcome these issues, this article proposes a novel MEC framework empowered by an unmanned aerial vehicle (UAV) relay and a reconfigurable intelligence surface (RIS). To fully exploit the potentials in terms of computation enhancement brought by the joint UAV and RIS design, we formulate a max–min computation capacity problem via determining the uplink signal detection, active beamforming of UAV, passive beamforming of RIS, time slot partition, computation bits of UAV, and UAV’s trajectory. We develop a concave–convex procedure (CCCP)-based algorithm in an alternating optimization manner over three subproblems to solve the formulated problem. It finds that the CCCP-based algorithm is conducive to decouple the intractable expressions by converting them into new but tractable second-order cone (SOC) constrains. To evaluate the performance of the proposed CCCP-based algorithm, we later design a direct algorithm by exploiting the implicit convexity of the problem. Simulation results demonstrate that the proposed CCCP-based algorithm derives a comparable performance as the direct algorithm, and achieves about 2.57-Mb max-min computation capacity higher compared with the straight flight case, and 8.08-Mb max–min computation capacity higher compared with the case without RIS, which validate the superiority of the joint UAV and RIS design for computation enhancement.","Title: Two-Time-Scale Hybrid Proactive and Reactive Edge Caching for Content Delivery Networks\nYear: 2022\n\nAbstract: In content delivery networks (CDNs), there usually exist two types of storage disks named hard disk drive (HDD) and solid state disk (SSD), which have different read speeds and cache sizes. By accounting such a practical hardware structure of CDNs and time-variant content popularity, we propose a novel two-time-scale caching strategy to determine the content placement in HDDs and SSDs. Specifically, we first propose a Stratification and Clustering based Ridge regression model with Laplacian regularization (SCRL) to predict the dynamic content popularity by utilizing both the video feature and user preference. The additional Laplacian regularization improves the prediction performance by leveraging the neighboring information of each video. Based on the predicted results, we then design an efficient hybrid proactive and reactive cache replacement strategy (HPRR) on a two-time-scale basis. Real-world trace-based numerical results show that the proposed prediction and caching strategy can significantly outperform the considered existing methods.","Title: Cellular-Connected Multi-UAV MEC Networks: An Online Stochastic Optimization Approach\nYear: 2022\n\nAbstract: In this paper, we consider a mobile edge computing (MEC) network where multiple cellular-connected unmanned aerial vehicles (UAVs) can offload their computation tasks to multiple ground base stations (GBSs). In practice, the UAVs are generally unable to master stochastic information of task arrival and channel changes in advance, which may cause a severe issue in terms of energy consumption. Therefore, we formulate a stochastic optimization problem with the goal of minimizing the average weighted sum energy consumption, by jointly optimizing UAV-GBS associations, communication and computation resource allocation, and three-dimensional (3D) UAV trajectories, during which a velocity-triggered penalty term (VTPT) is designed to suppress a large amount of the energy consumption of the UAVs. To handle the stochastic problem, we propose an online resource allocation and trajectory optimization algorithm with outer and inner structures. The outer structure transforms the original problem to a deterministic one by applying the Lyapunov-based optimization framework. The inner structure solves the obtained deterministic problem via the Lagrange duality method and the successive convex approximation technique, based on the block coordinate descent framework. Numerical results demonstrate that: 1) VTPT dramatically decreases the UAVs’ energy consumption, and 2) the proposed algorithm not only reduces the energy consumption but also ensures the computation queue stability compared with other benchmark schemes."],"string":"[\n \"Title: Cross-Layer Optimization of Two-Way Relaying for Statistical QoS Guarantees\\nYear: 2012\\n\\nAbstract: Two-way relaying promises considerable improvements on spectral efficiency in wireless relay networks. While most existing works focus on physical layer approaches to exploit its capacity gain, the benefits of two-way relaying on upper layers are much less investigated. In this paper, we study the cross-layer design and optimization for delay quality-of-service (QoS) provisioning in two-way relay systems. Our goal is to find the optimal transmission policy to maximize the weighted sum throughput of the two users in the physical layer while guaranteeing the individual statistical delay-QoS requirement for each user in the datalink layer. This statistical delay-QoS requirement is characterized by the QoS exponent. By integrating the concept of effective capacity, the cross-layer optimization problem is equivalent to a weighted sum effective capacity maximization problem. We derive the jointly optimal power and rate adaptation policies for both three-phase and two-phase two-way relay protocols. Numerical results show that the proposed adaptive transmission policies can efficiently provide QoS guarantees and improve the performance. In addition, the throughput gain obtained by the considered three-phase and two-phase protocols over direct transmission is significant when the delay-QoS requirements are loose, but the gain diminishes at tight delay requirements. It is also found that, in the two-phase protocol, the relay node should be placed closer to the source with more stringent delay requirement.\",\n \"Title: Efficient interference mitigating strategies for two-way relay channels.\\nYear: 2011\\n\\nAbstract: Hierarchical wireless networks have the potential to provide the needed capacity to a large number of mobile stations (MSs). According to this system architecture, the MSs are served by a dense network of fixed relay nodes (RNs) fed by a small number of large hub base stations (HBSs). In such deployment, high spectral efficiencies can be achieved if the RNs act as two-way relays; however this gives rise to co-channel interference (CCI) which needs to be mitigated. In order to gain insights on the impact of CCI to this scenario we consider an HBS with two highly directional antennas communicating with two MSs via two interfering two-way RNs. We investigate the average maximum sum-rate of two cooperative strategies. The first is based on Decode-and-Forward (DF) and network coding and acts as a baseline. The second strategy is based on Amplify-and-Forward (AF) and Network MIMO processing over both the backhaul and access channels. Furthermore we devise some cooperative protocols that utilize two, three or four time slots. It is shown that the 2-slot schemes perform generally better and that the DF strategy achieves superior performance when CCI is low while AF with Network MIMO is superior when CCI is high. © 2011 IEEE.\",\n \"Title: Generalized signal alignment for arbitrary MIMO two-way relay channels\\nYear: 2014\\n\\nAbstract: In this paper, we study the achievable degrees of freedom (DoF) for an arbitrary MIMO two-way relay channel, where there are K source nodes, each equipped with Mi antennas, for i = 1, 2, ⋯, K, and one relay node, equipped with N antennas. Each source node can exchange independent messages with an arbitrary set of other source nodes assisted by the relay. We extend our newly-proposed transmission scheme, generalized signal alignment (GSA) in [1], to the arbitrary MIMO two-way relay channel with antenna configuration satisfying N ≥ Mi + Mj, ∀i ≠ j. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a projected subspace at the relay. This is realized by jointly designing the precoding matrices at all source nodes and the processing matrix at the relay node. Moreover, the aligned subspaces are orthogonal to each other. Applying the GSA, we show that the DoF upper bound min {Σi=1K Mi, 2 Σi=2K Mi, 2N} is tight under the antenna configuration N ≥ max{Σi=1K Mi-Ms-Mt+ds, t | ∀s, t}. Here, ds, t denotes the DoF of the message exchanged between nodes s and t. In the special case when the arbitrary MIMO two-way relay channel reduces to the K-user MIMO Y channel, we show that our achievable region of DoF upper bound with GSA is larger than the existing result.\",\n \"Title: Robust Beamforming for Wireless Information and Power Transmission\\nYear: 2012\\n\\nAbstract: In this letter, we study the robust beamforming problem for the multi-antenna wireless broadcasting system with simultaneous information and power transmission, under the assumption of imperfect channel state information (CSI) at the transmitter. Following the worst-case deterministic model, our objective is to maximize the worst-case harvested energy for the energy receiver while guaranteeing that the rate for the information receiver is above a threshold for all possible channel realizations. Such problem is nonconvex with infinite number of constraints. Using certain transformation techniques, we convert this problem into a relaxed semidefinite programming problem (SDP) which can be solved efficiently. We further show that the solution of the relaxed SDP problem is always rank-one. This indicates that the relaxation is tight and we can get the optimal solution for the original problem. Simulation results are presented to validate the effectiveness of the proposed algorithm.\",\n \"Title: Nonlinear Precoding Design for MIMO Amplify-and-Forward Two-Way Relay Systems.\\nYear: 2012\\n\\nAbstract: In traditional multiple-input-multiple-output (MIMO) channel and MIMO one-way relay system, nonlinear precoding design has shown significant performance gain over linear design. In this paper, we aim to study nonlinear precoding design for MIMO amplify-and-forward (AF) two-way relay systems, where nonlinear minimal mean square error (MMSE) decision feedback equalizers (DFEs) are used in two destinations, and linear transmit precoding is applied at the source and relay nodes. We first investigate nonlinear precoding design, where the precoding is only conducted at two sources for a fixed-relay precoder. After some transformations, we prove that this design problem is convex, and an efficient algorithm is provided to find the optimal solution. Then, we consider the nonlinear joint precoding design to further incorporate relay precoding. Due to the nonconvexity of this problem, we first propose an iterative algorithm (Algorithm I) to approach the optimal solution. It is proven that Algorithm I is convergent and can converge to a stationary point of the joint design problem. Moreover, we present a simplified iterative algorithm (Algorithm II) for joint precoding design to reduce the design complexity. It is found that Algorithm II almost achieves the same performance as Algorithm I in most cases. Our simulation results show that the proposed nonlinear joint precoding design significantly outperforms the linear joint precoding design. It is also shown that the choice between the proposed nonlinear source precoding design and the linear relay precoding design is dependent on specific conditions. © 1967-2012 IEEE.\",\n \"Title: MIMO Two-Way Compress-and-Forward Relaying with Approximate Joint Eigen-Decomposition\\nYear: 2013\\n\\nAbstract: While compress-and-forward (CF) is one of the basic relay protocols in cooperative transmission, little is known about the optimal design of CF in multiple-input multiple-output (MIMO) two-way relay channels (TWRC). An intuitive method is to compress each element of the superimposed signal vector during the multiple-access (MAC) phase independently and with identical compression noise variance. In this paper, we introduce an improved compression method. The key idea is to apply approximate joint diagonalization (AJD) to realize simultaneous eigen-decomposition of the two channel matrices in the MAC phase of two-way relaying in an approximate manner. After that, a novel covariance matrix design of the compression noise vector is derived for sum-rate maximization. Numerical results show that the proposed CF design can improve the spectral efficiency, especially when the relay node is close to any of the two source nodes instead of in the midpoint.\",\n \"Title: Iteratively Decoded Variable Length Space-Time Coded Modulation: Code Construction and Convergence Analysis\\nYear: 2007\\n\\nAbstract: An iteratively decoded variable length space time coded modulation (VL-STCM-ID) scheme capable of simultaneously providing both coding and iteration gain as well as multiplexing and diversity gain is proposed. Non-binary unity-rate precoders are employed for assisting the iterative decoding of the VL-STCM-ID scheme. The discrete-valued source symbols are first encoded into variable-length codewords that are mapped to the spatial and temporal domains. Then the variable-length codewords are interleaved and fed to the precoder assisted modulator. More explicitly, the proposed VL-STCM-ID arrangement is a jointly designed iteratively decoded scheme combining source coding, channel coding, modulation as well as spatial diversity/multiplexing. As expected, the higher the source correlation, the higher the achievable performance gain of the scheme becomes. Furthermore, the performance of the VL-STCM-ID scheme is about 14.6 dB better than that of the fixed length STCM (FL-STCM) benchmarker at a source symbol error ratio of 10-4\",\n \"Title: Resource Allocation with Subcarrier Pairing in OFDMA Two-Way Relay Networks.\\nYear: 2012\\n\\nAbstract: This study considers an orthogonal frequency-division multiple-access (OFDMA)-based multi-user two-way relay network where multiple mobile stations (MSs) communicate with a common base station (BS) via multiple relay stations (RSs). We study the joint optimization problem of subcarrier-pairing based relay-power allocation, relay selection, and subcarrier assignment. The problem is formulated as a mixed integer programming problem. By using the dual method, we propose an efficient algorithm to solve the problem in an asymptotically optimal manner. Simulation results show that the proposed method can improve system performance significantly over the conventional methods. © 2012 IEEE.\",\n \"Title: Diagonal block space-time code design for diversity and coding advantage over flat fading channels\\nYear: 2004\\n\\nAbstract: The potential promised by multiple transmit antennas has raised considerable interest in space-time coding for wireless communications. In this paper, we propose a systematic approach for designing space-time trellis codes over flat fading channels with full antenna diversity and good coding advantage. It is suitable for an arbitrary number of transmit antennas with arbitrary signal constellations. The key to this approach is to separate the traditional space-time trellis code design into two parts. It first encodes the information symbols using a one-dimensional (M,1) nonbinary block code, with M being the number of transmit antennas, and then transmits the coded symbols diagonally across the space-time grid. We show that regardless of channel time-selectivity, this new class of space-time codes always achieves a transmit diversity of order M with a minimum number of trellis states and a coding advantage equal to the minimum product distance of the employed block code. Traditional delay diversity codes can be viewed as a special case of this coding scheme in which the repetition block code is employed. To maximize the coding advantage, we introduce an optimal construction of the nonbinary block code for a given modulation scheme. In particular, an efficient suboptimal solution for multilevel phase-shift-keying (PSK) modulation is proposed. Some code examples with 2-6 bits/s/Hz and two to six transmit antennas are provided, and they demonstrate excellent performance via computer simulations. Although it is proposed for flat fading channels, this coding scheme can be easily extended to frequency-selective fading channels.\",\n \"Title: A New SLNR-Based Linear Precoding for Downlink Multi-User Multi-Stream MIMO Systems\\nYear: 2010\\n\\nAbstract: Signal-to-leakage-and-noise ratio (SLNR) is a promising criterion for linear precoder design in multi-user (MU) multiple-input multiple-output (MIMO) systems. It decouples the precoder design problem and makes closed-form solution available. In this letter, we present a new linear precoding scheme by slightly relaxing the SLNR maximization for MU-MIMO systems with multiple data streams per user. The precoding matrices are obtained by a general form of simultaneous diagonalization of two Hermitian matrices. The new scheme reduces the gap between the per-stream effective channel gains, an inherent limitation in the original SLNR precoding scheme. Simulation results demonstrate that the proposed precoding achieves considerable gains in error performance over the original one for multi-stream transmission while maintaining almost the same achievable sum-rate.\",\n \"Title: Competitive scheduling for OFDMA systems with guaranteed transmission rate\\nYear: 2009\\n\\nAbstract: Next-generation broadband wireless standards use orthogonal frequency division multiple access (OFDMA) as the preferred physical layer multiple access scheme, especially for the downlink. Due to limited resources available at the base station, multi-user resource allocation is crucial for delivering the applications with various quality-of-service (QoS) demands. We study the OFDMA resource allocation problem for the adaptive modulation and coding (AMC) mode of mobile WiMAX, in which resources in the form of allocation units (AU) are to be allocated and the channel knowledge of only some good sub-channels for the users is available to the scheduler. The objective is to maximize the sum-rate for all the users while maintaining guaranteed minimum and maximum traffic rates for certain users under a total transmission power constraint. Two novel factors, band selectivity factor (BSF) and competition factor (CF), are introduced. Based on the two factors, we propose a sub-optimal approach, rate-guaranteed competitive scheduling (RCS). It is suitable to be deployed in practical systems and exploits multi-user diversity with very low complexity. Simulation results show that RCS can achieve almost 75% of throughput of the optimal solution.\",\n \"Title: Precoding design for cognitive two-way relay networks.\\nYear: 2012\\n\\nAbstract: We study precoding design for cognitive two-way relay networks (C-TWRNs). In C-TWRN, the multi-antenna secondary transmitter not only transmits its own signal to the secondary receiver, it also acts as relay to help forwarding signals of two primary users via two-way relaying in the licensed frequency band. Our objective is to design linear relay transceiver or precoder such that the achievable rate of the secondary user is maximized while maintaining rate requirements of the primary users. To achieve this goal, different relay strategies, i.e., amplify-and-forward (AF), bit level XOR based decode-and-forward (DF-XOR) and symbol level superposition coding based decode-and-forward (DF-SUP), are considered. By transforming these non-convex design problems into suitable forms, efficient optimization tools are used to find the optimal solutions of all the schemes. Closed-form solutions are also obtained under certain conditions.\",\n \"Title: Joint Source and Relay Optimization for Non-Regenerative MIMO Two-Way Relay Systems with Imperfect CSI.\\nYear: 2012\\n\\nAbstract: In this paper, we consider a non-regenerative MIMO two-way relay system with imperfect channel state information (CSI). We employ a stochastic approach to model the channel uncertainties and address the robust joint source and relay optimization problem based on the minimum mean squared error (MMSE) criterion. With imperfect CSI, the self-interference (SI) cannot be completely canceled at destinat...\",\n \"Title: A Transmission Scheme for Continuous ARQ Protocols over Underwater Acoustic Channels\\nYear: 2009\\n\\nAbstract: Due to the half-duplex property of the underwater acoustic channels, the classic stop-and-wait ARQ (SW-ARQ) and its variants are generally thought to be the only class of ARQ protocols that can be applied in underwater. When combined with the large propagation delay property of the underwater acoustic channels, the use of SW-ARQ and its variants makes the throughput performance of underwater acoustic communication systems very inefficient. In this paper, we propose a transmission scheme that takes advantage of the long propagation delay in underwater to enable the use of continuous ARQ protocols over underwater acoustic channels. Simulation results show that our proposed transmission scheme allows much higher throughput to be achieved than both the classic SW-ARQ and its variants, even when simple continuous ARQ protocols are used.\",\n \"Title: QoS-Aware Transmission Policies for OFDM Bidirectional Decode-and-Forward Relaying\\nYear: 2013\\n\\nAbstract: Two-way relaying can considerably improve spectral efficiency in relay-assisted bidirectional communications. However, the benefits and flexible structure of orthogonal frequency division multiplexing (OFDM)-based two-way relay systems is much less exploited. Moreover, most of existing works have not considered quality-of-service (QoS) provisioning for two-way relaying. In this paper, we consider ...\",\n \"Title: On the Maximum Achievable Sum-Rate of Interfering Two-Way Relay Channels.\\nYear: 2012\\n\\nAbstract: Hierarchical networks can provide very high data rates to multiple mobile stations (MSs) through a dense network of fixed relay nodes (RNs) fed by few hub base stations (HBSs). In order to achieve high spectral efficiencies RNs can act as two-way RNs. However the dense RN deployment gives rise to high co-channel interference (CCI) that limits sum-rate performance. In this letter we consider a simple hierarchical network consisting of an HBS with two highly directional antennas communicating with two MSs via two interfering two-way RNs. To mitigate CCI and boost sum-rates we propose a two-way relaying strategy based on AF combined with Network MIMO processing which is applied over the concatenation of the backhaul and access network channels. We compare our proposed strategy with a baseline DF approach and we show that it performs significantly better when CCI is dominant. © 2006 IEEE.\",\n \"Title: Impact of imperfect channel state information on ARQ schemes over rayleigh fading channels\\nYear: 2009\\n\\nAbstract: With imperfect channel state information (CSI) acquired by channel estimation at the receiver, the performances of automatic-repeat-request (ARQ) systems are evaluated as a function of the accuracy of channel estimation. A link between network-layer performances and physical-layer parameters is therefore established. We study in particular the goodput and the accepted packet error rate as a function of the channel estimation mean square error (MSE) and the factors which affect the MSE. The results enable us to analyze the optimum allocation of energy for data transmission and energy for pilot channel estimation so as to maximize the goodput.\",\n \"Title: Content-aware transmission with delay threshold in heterogeneous networks\\nYear: 2013\\n\\nAbstract: With the popularity of smart devices, content based internet services are growing rapidly. Different from real-time services, the end-to-end delay requirements of the contents are much less stringent. In this paper, we consider the delay-tolerant content-aware delivery in two-tier heterogeneous wireless networks. Taking transmit power consumption into account, we propose a new transmission framework by pushing users from macrocells to small cells at the cost of tolerable delay. We model the tolerable delay of content delivery in a stochastic way by considering users' interests. In this model, we adopt a progressively decreasing interest function which treats the delay as its argument. A modified Black-Scholes model is adopted to model the interest function. Thus, there exists a tradeoff between users' experience and power consumption. We consider power efficiency under a certain level of quality of experience (QoE) to handle this tradeoff. A content-aware transmission scheme with the optimal power efficiency is proposed. Simulation results show that under the maximal power efficiency criterion, about 18% of power consumption is reduced while about 90% of users' interests is preserved.\",\n \"Title: Optimal Channel and Relay Assignment in OFDM-Based Multi-Relay Multi-Pair Two-Way Communication Networks\\nYear: 2012\\n\\nAbstract: Efficient utilization of radio resources in wireless networks is crucial and has been investigated extensively. This letter considers a wireless relay network where multiple user pairs conduct bidirectional communications via multiple relays based on orthogonal frequency-division multiplexing (OFDM) transmission. The joint optimization of channel and relay assignment, including subcarrier pairing, subcarrier allocation as well as relay selection, for total throughput maximization is formulated as a combinatorial optimization problem. Using a graph theoretical approach, we solve the problem optimally in polynomial time by transforming it into a maximum weighted bipartite matching (MWBM) problem. Simulation studies are carried out to evaluate the network total throughput versus transmit power per node and the number of relay nodes.\",\n \"Title: Spectrum Leasing and Cooperative Resource Allocation in Cognitive OFDMA Networks\\nYear: 2012\\n\\nAbstract: This paper considers a cooperative orthogonal frequency division multiple access (OFDMA)-based cognitive radio network where the primary system leases some of its subchannels to the secondary system for a fraction of time in exchange for the secondary users (SUs) assisting the transmission of primary users (PUs) as relays. Our aim is to determine the cooperation strategies among the primary and secondary systems so as to maximize the sum-rate of SUs while maintaining quality-of-service (QoS) requirements of PUs. We formulate a joint optimization problem of PU transmission mode selection, SU (or relay) selection, subcarrier assignment, power control, and time allocation. By applying dual method, this mixed integer programming problem is decomposed into parallel per-subcarrier subproblems, with each determining the cooperation strategy between one PU and one SU. We show that, on each leased subcarrier, the optimal strategy is to let a SU exclusively act as a relay or transmit for itself. This result is fundamentally different from the conventional spectrum leasing in single-channel systems where a SU must transmit a fraction of time for itself if it helps the PU's transmission. We then propose a subgradient-based algorithm to find the asymptotically optimal solution to the primal problem in polynomial time. Simulation results demonstrate that the proposed algorithm can significantly enhance the network performance.\",\n \"Title: Game Theoretic Multimode Precoding Strategy Selection for MIMO Multiple Access Channels\\nYear: 2010\\n\\nAbstract: This paper is concerned with decentralized selection of multimode precoding strategy for multiple-input multiple-output (MIMO) multiple access channels. We formulate it as a discrete noncooperative game. This game is shown to possess at least one pure strategy Nash equilibrium (NE) and the optimal strategy profile which maximizes the sum rate constitutes a pure strategy NE. Then we propose a decentralized algorithm based on learning automata to achieve the NE. A repeated mechanism is introduced to improve the sum rate performance and a mechanism for adapting step size is designed to control the convergence speed. Simulation results show that the proposed algorithm, which only requires limited feedback, can achieve near optimal or optimal sum rate performance.\",\n \"Title: Sparse channel estimation for OFDM transmission over two-way works\\nYear: 2012\\n\\nAbstract: Compressed sensing (CS) has recently emerged as a powerful signal acquisition paradigm. CS enables the recovery of high-dimensional sparse signals from much fewer samples than usually required. Further, quite a few recent channel measurement experiments show that many wireless channels also tend to exhibit sparsity. In this case, CS theory can be applicable to sparse channel estimation and its effectiveness has been validated in point-to-point (P2P) communication. In this work, we study sparse channel estimation for two-way relay networks (TWRN). Unlike P2P systems, applying CS theory to sparse channel estimation in TWRN is much more challenging. One issue is that the equivalent channels (terminal-relay-terminal) may be no longer sparse due to the linear convolutional operation. On this basis, novel schemes are proposed to solve this problem and effectively improve the accuracy of TWRN channel estimation when using CS theory. Extensive numerical results are provided to corroborate the proposed studies.\",\n \"Title: Coordinated Multicast Beamforming in Multicell Networks.\\nYear: 2012\\n\\nAbstract: We study physical layer multicasting in multicell networks where each base station, equipped with multiple antennas, transmits a common message using a single beamformer to multiple users in the same cell. We investigate two coordinated beamforming designs: the quality-of-service (QoS) beamforming and the max-min SINR (signal-to-interference-plus-noise ratio) beamforming. The goal of the QoS beamf...\",\n \"Title: Channel Estimation for OFDM Systems over Doubly Selective Channels: A Distributed Compressive Sensing Based Approach.\\nYear: 2013\\n\\nAbstract: Channel estimation for an orthogonal frequency-division multiplexing (OFDM) broadband system over a doubly selective channel is very challenging. This is mainly due to the significant Doppler shift, which results in a time-frequency doubly-selective (DS) channel. The DS channel features a large number of channel coefficients, which introduces inter-carrier interference (ICI) and forces the need for allocating a large number of pilot subcarriers. To tackle this problem, in this paper we propose a novel channel estimation scheme based on distributed compressive sensing (DCS) theory. Taking advantage of the basis expansion model (BEM) and the channel sparsity in the delay domain, we transform the original DS channel into a novel two-dimensional channel model, where several jointly sparse BEM coefficient vectors become the estimation goal. Then a special decoupling form originating from a novel sparse pilot pattern is designed for such estimation, which results in an ICI-free structure and enables the DCS application to make joint estimation of these vectors accurately. Combined with a smoothing treatment process, the proposed scheme can achieve significantly higher estimation accuracy than the existing ones, although with a much smaller number of pilot subcarriers. Theoretical analysis and simulation results both confirm its performance merits. © 2013 IEEE.\",\n \"Title: Linear Precoding Designs for Amplify-and-Forward Multiuser Two-Way Relay Systems\\nYear: 2012\\n\\nAbstract: Two-way relaying can improve spectral efficiency in two-user cooperative communications. It also has great potential in multiuser systems. A major problem of designing a multiuser two-way relay system (MU-TWRS) is transceiver or precoding design to suppress co-channel interference. This paper aims to study linear precoding designs for a cellular MU-TWRS where a multi-antenna base station (BS) conducts bi-directional communications with multiple mobile stations (MSs) via a multi-antenna relay station (RS) with amplify-and-forward relay strategy. The design goal is to optimize uplink performance, including total mean-square error (Total-MSE) and sum rate, while maintaining individual signal-to-interference-plus-noise ratio (SINR) requirement for downlink signals. We show that the BS precoding design with the RS precoder fixed can be converted to a standard second order cone programming (SOCP) and the optimal solution is obtained efficiently. The RS precoding design with the BS precoder fixed, on the other hand, is non-convex and we present an iterative algorithm to find a local optimal solution. Then, the joint BS-RS precoding is obtained by solving the BS precoding and the RS precoding alternately. Comprehensive simulation is conducted to demonstrate the effectiveness of the proposed precoding designs.\",\n \"Title: Analysis of Differential Unitary Space-Time Modulation over Non-Identical MIMO Channels\\nYear: 2008\\n\\nAbstract: We present an analytical study on the error performance of differential unitary space-time modulation (DUSTM) over multiple-input multiple-output (MIMO) channels with non- identical fading statistics. The channel for each transmit-receive antenna pair is assumed to be independent, non-identically distributed (i.n.i.d), and time-varying Rayleigh fading. We first show that the maximum-likelihood (ML) differential detector of DUSTM over such channels is involved except for differential cyclic group codes. Applying the distribution of quadratic forms of Gaussian vectors, we derive closed-form expressions for the exact error probabilities of two specific unitary classes, namely, cyclic group codes and orthogonal codes. Simple and useful asymptotic bounds are also obtained. Our analysis leads to several general findings.\",\n \"Title: Superimposed XOR: a new physical layer network coding scheme for two-way relay channels\\nYear: 2009\\n\\nAbstract: We present a new physical layer network coding (PLNC) scheme, called superimposed XOR, for two-way relay channels. The new scheme specifically takes into account the channel as well as information asymmetry in the broadcast phase of two-way relaying. It is based upon both bitwise XOR and symbol-level superposition coding. We first derive its achievable rate regions when integrated with two known time control protocols over Gaussian channels. We then demonstrate its average maximum sum-rate and service delay performance over fading channels. Compared with the existing bitwise XOR and symbol-level superposition coding, the proposed superimposed XOR scheme achieves larger rate region in asymmetric channels. As a result, it performs much better in terms of averaged maximum sum-rate and service delay over fading channels. Numerical results also show that the proposed practical PLNC closely approaches the capacity bound given by the information-theoretic random binning.\",\n \"Title: Optimization framework and graph-based approach for relay-assisted bidirectional OFDMA cellular networks\\nYear: 2010\\n\\nAbstract: This paper considers a relay-assisted bidirectional cellular network where the base station (BS) communicates with each mobile station (MS) using orthogonal frequency-division multiple-access (OFDMA) for both uplink and downlink. The goal is to improve the overall system performance by exploring the full potential of the network in various dimensions including user, subcarrier, relay, and bidirectional traffic. In this work, we first introduce a novel three-time-slot time-division duplexing (TDD) transmission protocol. This protocol unifies direct transmission, one-way relaying and network-coded two-way relaying between the BS and each MS. Using the proposed three-time-slot TDD protocol, we then propose an optimization framework for resource allocation to achieve the following gains: cooperative diversity (via relay selection), network coding gain (via bidirectional transmission mode selection), and multiuser diversity (via subcarrier assignment). We formulate the problem as a combinatorial optimization problem, which is NP-complete. To make it more tractable, we adopt a graph-based approach. We first establish the equivalence between the original problem and a maximum weighted clique problem (MWCP) in graph theory. A metaheuristic algorithm based on ant colony optimization (ACO) is then employed to find the solution in polynomial time. Simulation results demonstrate that the proposed protocol together with the ACO algorithm significantly enhances the system total throughput.\",\n \"Title: Outage Probability and Finite-SNR Diversity–Multiplexing Tradeoff for Two-Way Relay Fading Channels\\nYear: 2013\\n\\nAbstract: In this paper, we analyze the outage probability and finite-SNR diversity-multiplexing tradeoff (f-DMT) performance for two-way relay channels (TWRCs). Both amplify-and-forward (AF) and decode-and-forward (DF) relay protocols are considered. The two source nodes are equipped with single antenna, and the relay is equipped with single or multiple antennas. First, we derive lower bounds of outage probability for single- and multiantenna relay AF, upper and lower bounds for multiantenna relay DF, and the exact closed-form expression for single-antenna DF. These results are suitable for arbitrary time-sharing and rate allocation for DF and arbitrary rate allocation for AF. Numerical results show that the derived lower bounds approximate very well the actual outage performance obtained by Monte Carlo simulation. Based on the tight lower bounds, we further derive estimates of the f-DMTs. We find that AF always outperforms DF in terms of f-DMT in all SNR regimes. However, the comparison result of outage performance between AF and DF depends on channel conditions. Finally, we also discuss the impact of relay location, time-sharing, and rate allocation on the outage and f-DMT via numerical examples.\",\n \"Title: Secure Beamforming for MIMO Two-Way Communications With an Untrusted Relay\\nYear: 2014\\n\\nAbstract: This paper studies the secure beamforming design in a multiple-antenna three-node system where two source nodes exchange messages with the help of an untrusted relay node. The relay acts as both an essential signal forwarder and a potential eavesdropper. Both two-phase and three-phase two-way relay strategies are considered. Our goal is to jointly optimize the source and relay beamformers for maximizing the secrecy sum rate of the two-way communications. We first derive the optimal relay beamformer structures. Then, iterative algorithms are proposed to find source and relay beamformers jointly based on alternating optimization. Furthermore, we conduct asymptotic analysis on the maximum secrecy sum-rate. Our analysis shows that when all transmit powers approach infinity, the two-phase two-way relay scheme achieves the maximum secrecy sum rate if the source beamformers are designed such that the received signals at the relay align in the same direction. This reveals an important advantage of signal alignment technique in against eavesdropping. It is also shown that if the source powers approach zero, the three-phase scheme performs the best while the two-phase scheme is even worse than direct transmission. Simulation results have verified the efficiency of the proposed secure beamforming algorithms as well as the analytical findings.\",\n \"Title: Utility-Based Wireless Resource Allocation for Variable Rate Transmission\\nYear: 2007\\n\\nAbstract: For most wireless services with variable rate transmission, both average rate and rate oscillation are important performance metrics. The traditional performance criterion, utility of average transmission rate, boosts the average rate but also results in high rate oscillations. We introduce a utility function of instantaneous transmission rates. It is capable of facilitating the resource allocation with flexible combinations of average rate and rate oscillation. Based on the new utility, we consider the time and power allocation in a time-shared wireless network. Two adaptation policies are developed, namely, time sharing (TS) and joint time sharing and power control (JTPC). An extension to quantized time sharing with limited channel feedback (QTSL) for practical systems is also discussed. Simulation results show that by controlling the concavity of the utility function, a tradeoff between the average rate and rate oscillation can be easily made.\",\n \"Title: Graph-Based Optimization for Relay-Assisted Bidirectional Cellular Networks\\nYear: 2010\\n\\nAbstract: This paper considers a relay-assisted bidirectional cellular network where the base station (BS) communicates with each mobile station (MS) using orthogonal frequency-division multiple-access (OFDMA) for both uplink and downlink. We first introduce a novel three-time-slot time-division duplexing (TDD) transmission protocol. This protocol unifies the direct transmission, one-way relaying and network-coded two-way relaying between the BS and each MS. Using the proposed TDD protocol, we then propose an optimization framework for resource allocation to achieve the following gains: cooperative diversity gain (via relay selection), network coding gain (via bidirectional transmission mode selection), and multiuser diversity gain (via subcarrier assignment). We formulate the problem as an integer programming problem. By establishing its equivalence with a maximum weighted clique problem (MWCP) in graph theory, we show that the problem can be solved using an ant colony optimization (ACO) based metaheuristic algorithm in polynomial time. Simulation results demonstrate that the proposed protocol together with the ACO algorithm significantly enhances the system total throughput compared with conventional schemes.\",\n \"Title: Cross-layer resource allocation of two-way relaying for statistical delay-QoS guarantees\\nYear: 2012\\n\\nAbstract: In this paper, we consider the cross-layer design for delay quality-of-service (QoS) provisioning in two-way relay systems. We aim to find the optimal resource allocation policy to maximize the weighted sum-rate while guaranteeing the statistical delay-QoS requirements for both users. The delay requirement is characterized as the QoS exponent. With the integration of the concept of effective capacity, the cross-layer optimization problem is equivalent to a weighted sum effective capacity maximization problem. We derive the optimal joint power and rate adaptation policy for the two-phase two-way relaying. Numerical results show that the proposed policy can efficiently support diverse QoS requirements and significantly improve the performance compared with both the fixed power scheme and the weight-based method.\",\n \"Title: Finite-SNR Diversity-Multiplexing Tradeoff for Two-Way Relay Fading Channel\\nYear: 2010\\n\\nAbstract: This paper studies the performance limits of two-way relay channel (TWRC) at finite signal-to-noise ratio (SNR) in Rayleigh fading environment. A two-phase decode-and-forward (DF) protocol is considered. We first derive closed-form expressions for both outage probability and diversity-multiplexing tradeoff (DMT). Our results are general and suitable for any time sharing and any rate allocation in the two-way relay protocol. It is found that DF outperforms amplify-and-forward (AF) when either multiplexing gain or SNR is small enough, otherwise, DF is inferior to AF in term of outage probability. Meanwhile, finite-SNR DMT of DF is always lower than that of AF regardless of SNR due to the additional sum-rate constraint imposed on the relay node for full decoding. Furthermore, the optimum relay location for any given combination of time sharing and rate allocation is presented.\",\n \"Title: Degrees of Freedom for MIMO Two-Way X Relay Channel\\nYear: 2013\\n\\nAbstract: We study the degrees of freedom (DOF) of a multiple-input multiple-output (MIMO) two-way X relay channel, where there are two groups of source nodes and one relay node, each equipped with multiple antennas, and each of the two source nodes in one group exchanges independent messages with the two source nodes in the other group via the relay node. It is assumed that every source node is equipped with $M$ antennas while the relay is equipped with $N$ antennas. We first show that the upper bound on the total DOF for this network is $2\\\\min\\\\{2M, N\\\\}$ and then focus on the case of $N\\\\leq 2M$ so that the DOF is upper bounded by twice the number of antennas at the relay. By applying signal alignment for network coding and joint transceiver design for interference cancellation, we show that this upper bound can be achieved when $N\\\\leq\\\\lfloor{8M\\\\over 5}\\\\rfloor$. We also show that with signal alignment only but no joint transceiver design, the upper bound is achievable when $N\\\\leq\\\\lfloor{4M\\\\over 3}\\\\rfloor$. Simulation results are provided to corroborate the theoretical results and to demonstrate the performance of the proposed scheme in the finite signal-to-noise ratio regime.\",\n \"Title: Pseudo Exclusive-OR for LDPC Coded Two-Way Relay Block Fading Channels.\\nYear: 2011\\n\\nAbstract: We present a novel adaptive physical layer network coding (PLNC) at the relay, called pseudo exclusive-or (PXOR), for LDPC coded two-way relay (TWR) block fading channels. Based on the pairwise check decoding (PCD), the check relationship table generated by the proposed PXOR mapping obtains the same Hamming distances of the PLNC mapped codewords as that of conventional XOR mapping. In the meantime, the PXOR mapping optimizes the Euclidean distances by adjusting the symbol distances dynamically as far as possible in order to compensate the amplitude fading and phase deviation of the TWR block fading channels. For the system end-to-end error probability, simulation results show that the proposed coded PXOR considerably outperforms the coded conventional XOR and achieves the same performance as the complicated coded CNC for considered two TWR block fading channels. © 2011 IEEE.\",\n \"Title: Linear Precoding for Multi-Pair Two-Way MIMO Relay Systems With Max-Min Fairness\\nYear: 2012\\n\\nAbstract: Two-way relaying has demonstrated significant gain in spectral efficiency by applying network coding when a pair of source nodes exchange information via a relay node. This paper is concerned with the scenario where multiple pairs of users exchange information through a common relay node equipped with multiple antennas. We aim to design linear precoding at the relay based on amplify-and-forward strategy. The goal is to maximize the minimum achievable rate among all the users subject to a peak relay power constraint so as to achieve the max-min fairness. We first convert this nonconvex problem into a series of semidefinite programming problems using bisection search and certain transformation techniques. A quasi-optimal solution is then obtained by using semidefinite relaxation (SDR). To reduce the design complexity, we further introduce a pair-wise zero-forcing (ZF) structure that eliminates the interference among different user pairs. By applying this structure, the precoding design problem is simplified to a power allocation problem which can be optimally solved. A simplified power allocation algorithm is also proposed. Simulation results show that the proposed SDR-based precoding not only achieves high minimum user rate but also maintains good sum-rate performance when compared with existing schemes. It is also shown that the proposed pair-wise ZF precoding with simplified power allocation strikes a good balance between performance and complexity.\",\n \"Title: A hybrid relay selection scheme using differential modulation\\nYear: 2009\\n\\nAbstract: In this paper, we propose a hybrid relay selection (HRS) scheme in a general cooperative network using differential modulation. In the HRS scheme, when the destination decodes successfully, the relay nodes will remain silent. Otherwise, optimal relay node has to be determined to make an additional transmission. In this process, all the relays are divided into two groups, referred to as an amplify-and-forward (AAF) relay group and a decode-and-forward (DAF) relay group depending on whether they can decode correctly or not. The relay, which has the maximum signal-to-noise ratio (SNR) at the destination, will be selected from both AAF and DAF relay groups. Simulation results show that the proposed relay selection scheme significantly outperforms the conventional AAF selection in terms of both frame error rate (FER) and throughput, and these performance gains considerably grow as the number of relay nodes increases.\",\n \"Title: Generalized signal alignment for MIMO two-way X relay channels\\nYear: 2014\\n\\nAbstract: We study the degrees of freedom (DoF) of MIMO two-way X relay channels. Previous work studied the case N <; 2M, where N and M denote the number of antennas at the relay and each source, respectively, and showed that the maximum DoF of 2N is achievable when N <; ⌊8M/5⌋ by applying signal alignment (SA) for network coding and interference cancelation. This work considers the case N > 2M where the performance is limited by the number of antennas at each source node and conventional SA is not feasible. We propose a generalized signal alignment (GSA) based transmission scheme. The key is to let the signals to be exchanged between every source node align in a transformed subspace, rather than the direct subspace, at the relay so as to form network-coded signals. This is realized by jointly designing the precoding matrices at all source nodes and the processing matrix at the relay. Moreover, the aligned subspaces are orthogonal to each other. By applying the GSA, we show that the DoF upper bound 4M is achievable when M ≤ ⌊ 2N/5 ⌋ (M is even) or M ≤ ⌊ 2N-1 /5 ⌋ (M is odd). Numerical results also demonstrate that our proposed transmission scheme is feasible and effective.\",\n \"Title: Generalized layered space-time codes for high data rate wireless communications\\nYear: 2004\\n\\nAbstract: We present the architecture of generalized layered space-time codes (GLST) as a combination of Bell Labs layered space-time (BLAST) architecture and space-time coding (STC) in multiple-antenna wireless communication systems. This approach provides both spectral and power efficiency with moderate complexity. The framework is to partition all the available transmit antennas into groups and apply STC on each group as component codes. Based on the mappings from coded symbols to transmit antenna groups, we can construct different GLST systems. Particularly, horizontal mapping and diagonal mapping are introduced and referred to as HGLST and DGLST respectively. The basic decoding of GLST, under quasi-static flat Rayleigh fading environments and assuming perfectly known channel state information (CSI) at the receiver, combines group interference suppression and group interference cancellation techniques. As a result, the individual STC on each group is decoded serially. To improve the overall system performance, we derive the optimal power allocation among all space-time codewords without requiring the knowledge of CSI at the transmitter and suitable for all GLST systems. We also derive the optimal serial decoding order based on the channel realizations at the receiver for HGLST systems without power allocation. Simulation results show that both can provide much improvement. To further enhance the system performance, we propose a low complexity hard-decision iterative decoding method. This method efficiently exploits full receive antenna diversity and, hence, dramatically improves the system performance which is confirmed by simulation.\",\n \"Title: Distributed cross-layer resource allocation for statistical QoS provisioning in femtocell networks\\nYear: 2013\\n\\nAbstract: In this paper, we study the cross layer design and optimization for delay quality-of-service (QoS) provisioning in spectrum sharing femtocell networks. Our goal is to find the optimal resource allocation policy to maximize the throughput for each femtocell user, addressing the co-channel interference problem in the physical layer and the individual statistical delay-QoS guarantee problem from the upper layers. The statistical delay-QoS requirement is characterized by the QoS exponent. By integrating the concept of effective capacity, the cross-layer optimization problem is formulated as an effective capacity maximization game. With partial dual decomposition, this game is solved through a hierarchical structure. Specifically, we derive the optimal power allocation policy for femtocell users and design a distributed algorithm to obtain the Nash Equilibrium (N.E.). Numerical results show that the proposed policy can efficiently improve the performance of the networks.\",\n \"Title: Joint subchannel and power allocation in interference-limited OFDMA femtocells with heterogeneous QoS guarantee\\nYear: 2012\\n\\nAbstract: In this paper, we consider the joint subchannel and power allocation problem in both the uplink and the downlink for two-tier networks comprising spectrum-sharing macrocells and femtocells. A joint subchannel and power allocation scheme for co-channel femtocells is proposed, aiming to maximize the capacity for delay-tolerant users subject to delay-sensitive users' quality of service and interference constraints imposed by macrocells. The joint subchannel and power allocation problem is modeled as an mixed integer programming problem, then transformed into a convex optimization problem by relaxing subchannel sharing, and finally solved by a dual decomposition approach. The effectiveness of the proposed approach is verified by simulations and compared with existing scheme.\",\n \"Title: Auction-Based Optimal Power Allocation in Multiuser Cooperative Networks.\\nYear: 2011\\n\\nAbstract: Cooperative Caching can be an effective mechanism for reducing electronic content provisioning cost in Social Wireless Networks (SWNETs) which are formed by a collection of mobile data enabled phones physically gathering in settings such as university campus, malls, airport and other public places. In this paper, we first propose an optimal collaborative object caching policy in order to minimize the object provision cost in SWNETs with homogenous user requests and a peer-rebate model for promoting collaboration. Then using an analytical model we study the impacts of user selfishness on the provisioning cost and the earned rebate when certain nodes in an SWNET selfishly deviate from the optimal policy in order to increase their individually earned rebate. The analytical model is extensively validated by experimental results from simulated SWNETs using the network simulator ns2.\",\n \"Title: Finite-SNR Diversity-Multiplexing Tradeoff for Two-Way Multi-Antenna Relay Fading Channels\\nYear: 2010\\n\\nAbstract: In this paper, we study the diversity-multiplexing tradeoff (DMT) of two-way relay channels (TWRC) with multi-antenna relay at finite signal-to-noise ratio (SNR). A two-phase decode-and-forward (DF) relay protocol and Rayleigh fading environment are considered. We first derive upper and lower bounds on the outage probability. These bounds are very tight for all practical SNR regions. Based on these bounds, the estimates of finite-SNR DMT (f-DMT) are then obtained. Our analysis shows that the multiplexing gain approaches one when SNR decreases to zero. On the other hand, the diversity gain approaches the number of relay antennas when SNR increases to infinity. Furthermore, the impact of time sharing, rate allocation and relay location on the outage and f-DMT is also discussed through numerical examples.\",\n \"Title: High rate trellis coded differential unitary space-time modulation via super unitarity\\nYear: 2006\\n\\nAbstract: We introduce a new trellis coded differential unitary space-time modulation scheme for multiple-antenna wireless systems. In the new scheme, the constellation expansion is executed using a super unitarity technique so that the number of available unitary matrices is increased but the transmitted symbol alphabet is kept the same. A novel set partitioning strategy is then applied to the expanded matrix set. This scheme avoids the rate-loss problem suffered by traditional code design. We provide some examples using the proposed code construction method. Compared with existing ones, the new codes can not only achieve lower transmitter and receiver complexity, but also provide higher coding gains\",\n \"Title: Secure beamforming for MIMO two-way transmission with an untrusted relay\\nYear: 2013\\n\\nAbstract: From security perspective, a friendly relay may help to keep the confidential messages from being eavesdropped, while an untrusted relay may intentionally eavesdrop the messages when relaying. This paper studies the secure beamforming for multiple-input multiple-output (MIMO) two-way communications, where two source nodes exchange information with the help of an untrusted relay node. The relay adopts amplify-and-forward (AF) strategy and acts as both an essential helper and a potential eavesdropper. Our goal is to maximize the secrecy sum rate of the bidirectional links by jointly optimizing the source and relay beamformers. For the two-phase two-way relay scheme, we first derive the optimal structure of the relay beamformer and then propose an iterative algorithm to jointly optimize the source and relay beamformers. Then, a comprehensive study on the asymptotical performance is conducted by letting the source and relay powers approach zero or infinity. In particular, we show that when all powers approach infinity, the two-way relay scheme achieves the maximum secrecy rate if the transceiver beamformers are designed such that the received signals at the relay can be aligned to be parallel.\",\n \"Title: Cooperative jamming for secrecy in decentralized wireless networks\\nYear: 2012\\n\\nAbstract: Cooperative jamming as a physical layer security enhancement has recently drawn considerable attention. While most existing works focus on communication systems with a small number of nodes, we investigate the use of cooperative jamming for providing secrecy in large-scale decentralized networks consisting of randomly distributed legitimate users and eavesdroppers. A modified slotted ALOHA protocol, named CJ-ALOHA, is considered where each legitimate transmitter either sends its message signal or acts as a helping jammer according to a message transmission probability p. We derive the secrecy transmission capacity to characterize the network throughput and show how the throughput is affected by the CJ-ALOHA protocol. Both analytical and numerical insights are provided on the design of the CJ-ALOHA protocol for optimal throughput performance.\",\n \"Title: A Network Flow Approach to Throughput Maximization in Cooperative OFDMA Networks.\\nYear: 2013\\n\\nAbstract: In wireless cooperative orthogonal frequency-division multiple-access (OFDMA) networks, it is important to adapt the transmission strategies for each user according to the network channel dynamics in order to optimize the overall system performance. The adaption involves transmission mode selection (a user can choose from direct or cooperative transmission), subcarrier assignment, subcarrier pairing (the incoming and outgoing subcarriers at the relay for cooperative transmission need to be matched), relay selection, as well as power allocation and hence is highly challenging. Many previous works only consider a subset of the adaptation. In this paper, we tackle the joint optimization problem using a network flow approach. Specifically, we first show that for given power allocation, the combinatorial optimization problem of transmission mode selection, subcarrier assignment, relay selection and subcarrier pairing for the system total throughput maximization can be transformed into a minimum cost network flow (MCNF) problem with integer solutions. The linear optimal distribution (LOD) algorithm is applied to find the optimal solution in polynomial time. We then solve the mixed integer programming problem of the joint assignment and power allocation in an asymptotically optimal way in the dual domain. Simulation results show that the proposed algorithms can significantly enhance the overall system throughput. © 2002-2012 IEEE.\",\n \"Title: Power Efficiency for Device-to-Device Communications.\\nYear: 2013\\n\\nAbstract: The concept of device-to-Device (D2D) communication as an underlay coexistence with cellular networks gains many advantages of improving system performance. In this paper, we model such a two-layer heterogenous network based on stochastic geometry approach. We aim at minimizing the expected power consumption of the D2D layer while satisfying the outage performance of both D2D layer and cellular layer. We consider two kinds of power control schemes. The first one is referred as to independent power control where the transmit powers are statistically independent of the networks and all channel conditions. The second is named as dependent power control where the transmit power of each user is dependent on its own channel condition. A closed-form expression of optimal independent power control is derived, and we point out that the optimal power control for this case is fixed and not relevant to the randomness of the network. For the dependent power control case, we propose an efficient way to find the close-to-optimal solution for the power-efficiency optimization problem. Numerical results show that dependent power control scheme saves about half of power that the independent power control scheme demands.\",\n \"Title: An optimal graph approach for optimizing OFDMA relay networks\\nYear: 2012\\n\\nAbstract: This paper considers a relay-assisted cooperative network where multiple relays assist the communication of multiple users using orthogonal frequency-division multiple-access (OFDMA). Our goal is to improve system performance by exploring full potential of the network in various dimensions, including user, relay, channel, and transmission mode. We formulate the joint optimization of subcarrier pairing, subcarrier assignment, relay selection, and transmission mode selection. We show that this combinatorial optimization problem can be transformed into a minimum cost network flow (MCNF) problem with integer solutions in graph theory. Then the linear optimal distribution (LOD) algorithm is applied to find the optimal solution in polynomial time. Simulations show that the proposed algorithm can significantly enhance the overall system throughput.\",\n \"Title: Optimal power allocation scheme on generalized layered space-time coding systems.\\nYear: 2001\\n\\nAbstract: We consider a generalized layered Space-Time(GLST) architecture with parallel Space-Time (ST) codes andderive an optimal power allocation (PA) scheme over the Space-Time encoders to minimize the overall frame error rate. Weprove that the optimal power allocation scheme will equate thederivatives of the frame error rate functions of all the ST codes.From simulation, we show that the derived optimal powerallocation has a 1-2 dB gain over equal power scheme. Also, theproposed scheme has a...\",\n \"Title: Design an asynchronous radio interferometric positioning system using dual-tone signaling\\nYear: 2013\\n\\nAbstract: Radio interferometric positioning systems (RIPS) are recently proposed for low-complexity and high-accuracy localization. However, the original RIPS involves four nodes (two transmitters and two receivers) for a ranging session, and requires stringent time synchronization upon two receivers. In this paper, an asynchronous radio interferometric positioning system (ARIPS) is developed with larger positioning ranges. In ARIPS, two anchors (nodes with known positions) transmit two slightly different dual-tone signals. The differences of the two dual-tone signals create two low-frequency differential signals at the target receiver. The phase differences of the differential signals bear the time-difference-of-arrival (TDOA) information, i.e., the distance information. We develop two new methods to estimate the TDOA with and without accurate knowledge of the frequencies of the differential signals, respectively. By switching the pairs of the anchor nodes, several TDOAs can be obtained and thus the location of the target node can be estimated. The proposed ARIPS is robust to carrier frequency offsets (CFOs) and random phases due to asynchronous oscillators, and increases the resolving range limit due to the well-known integer ambiguity issue. Simulation results illustrate the performance of the proposed ARIPS.\",\n \"Title: Hash function mapping design utilizing probability distribution for pre-image resistance\\nYear: 2012\\n\\nAbstract: Hash functions are often used to protect the integrity of information. In general, the design of hash functions should satisfy three standards: pre-image resistance, second pre-image resistance and collision resistance. The design of hash functions in the literature assumes that the messages to be transmitted are equally probable. In this paper, we focus on the pre-image resistance and investigate the problem of mapping design for hash function utilizing the unequal occurrence probabilities of the messages. We first present a necessary condition for the optimal mapping and then introduce a heuristic algorithm. Simulation experiments are carried out to evaluate the performance of the proposed new design. It is shown that the probability of successful attack can be significantly reduced compared with the conventional design. Our algorithm can be useful in scenarios where the attacker has limited ability or time to estimate the probability distribution of the messages. To our best knowledge, this work is the first attempt of making use of the message distribution in designing hash functions for information security.\",\n \"Title: Joint Source and Relay Precoding Designs for MIMO Two-Way Relay Systems\\nYear: 2011\\n\\nAbstract: We investigate the source and relay precoding based on the minimum mean-square-error (MMSE) criterion for amplify-and-forward (AF) MIMO two-way relay systems. This joint design problem is shown to be a highly nonconvex optimization problem. In this work, we present two efficient design algorithms. The first one aims to minimize the total MSE of two users by alternatively solving three trackable sub-problems and it is iterative in nature. Since the optimal solution for each sub-problem can be obtained, the convergence is thus ensured. The second design aims to compromise computational complexity and system performance and possesses a certain precoder structure. This structure is able to parallelize channels in the Multiple Access (MAC) and Broadcast (BC) phases of the two-way relaying. Based on such structure, the joint precoding design is simply reduced to the joint source and relay power allocation problem. The efficiency of both proposed algorithms is verified through simulation.\",\n \"Title: Alternative Awaiting and Broadcast for Two-Way Relay Fading Channels\\nYear: 2011\\n\\nAbstract: We investigate a two-way relay (TWR) fading channel where two source nodes wish to exchange information with the help of a relay node. Given traditional TWR protocols, transmission rates in both directions are known to be limited by the hop with lower capacity, i.e., the min operations between uplink and downlink. In this paper, we propose a new transmission protocol, called alternative awaiting and broadcast (AAB), to cancel the min operations in the TWR fading channels. The operational principles, a new upper bound on ergodic sum capacity (ESC), and a convergence behavior of the average delay of signal transmission (ST) (in the relay buffer) for the proposed AAB protocol are analyzed. Moreover, we propose a suboptimal encoding/decoding solution for the AAB protocol and derive an achievable ergodic sum rate (ESR) with a corresponding average delay of ST. Numerical results show that 1) the proposed AAB protocol significantly improves the achievable ESR compared with the traditional TWR protocols, and 2) considering the average delay of system service (SS) (in the source buffer), the average delay of ST induced by the proposed AAB protocol is very small and negligible.\",\n \"Title: Non-Cooperative Power Control for Faded Wireless Ad Hoc Networks\\nYear: 2007\\n\\nAbstract: The problem of non-cooperative power control is studied for wireless ad hoc networks supporting data services. We develop a maximum throughput based non-cooperative power control game (MT-NPG), where each transmitter node requires only the effective interference measurement from its corresponding receiver. An expression for the optimal power control to maximize the average transmission rate for each individual link is derived. Then, we design a distributed iterative power updating algorithm to approximate the optimal solution. The existence and uniqueness of Nash equilibrium for the proposed game is investigated. Simulation results show that the proposed MT-NPG yields a significant improvement in the sum of average achievable rates when compared with existing approaches.\",\n \"Title: Blind Spectrum Sensing by Information Theoretic Criteria\\nYear: 2010\\n\\nAbstract: Information theoretic criteria (ITC) based spectrum sensing is a promising blind method which can reliably detect the primary users while requiring little prior information in cognitive radio networks. In this paper, we provide an intensive treatment on the ITC sensing. We first introduce a new over-determined channel model constructed by applying multiple antennas in order to make the ITC applicable. Then, a simplified ITC sensing algorithm is introduced, which needs to compute and compare only two decision values. Compared with the original ITC (OITC) sensing algorithm, the simplified algorithm significantly reduces the computational complexity without losing any performance. Furthermore, applying the recent advances in random matrix theory, we derive closed-form expressions to tightly approximate both the probability of false alarm and probability of detection. Finally, comprehensive simulations are carried out to evaluate the performance of the proposed ITC sensing algorithms. Results show that they considerably outperform existing blind spectrum sensing methods in certain cases.\",\n \"Title: Effects of non-identical rayleigh fading on differential unitary space-time modulation\\nYear: 2007\\n\\nAbstract: Non-identical fading distribution in a multiple-input multiple-output (MIMO) channel, including unequal average channel gains and fade rates, often occurs when antennas are not co-located. In this paper, we present an analytical study of the effects of non-identical Rayleigh fading on the error performance of differential unitary space-time modulation (DUSTM). The fading processes for different transmit-receive antenna pairs are assumed to be independent and time-variant. We find that the maximum-likelihood (ML) differential detector of DUSTM over such channels is involved except for differential cyclic group codes. The conventional detector is proved to be asymptotically optimal in the limit of high signal-to-noise ratio (SNR) over static fading channels. Applying the distribution of quadratic forms of Gaussian vectors, we then derive closed-form expressions for the exact error probabilities of two specific unitary classes, namely, cyclic group codes and orthogonal codes. Simple and useful asymptotic bounds on error probabilities are also obtained. Our analysis leads to the following general findings: (1) equal power allocation is asymptotically optimal, and (2) non-identical channel gain distribution degrades the error performance. Finally, we also introduce a water-filling based power allocation to exploit the transmit non-identical fading statistics.\",\n \"Title: Adaptive Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems\\nYear: 2006\\n\\nAbstract: Most existing work on adaptive allocation of subcarriers and power in multiuser OFDM systems has focused on homogeneous traffic consisting of delay-constrained data (guaranteed service) or delay-tolerant data (best-effort service) only. In this work, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and no-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the DC traffic under a total transmission power constraint. Finding the optimal allocation of subcarriers and power is formulated as a convex programming problem. An iterative algorithm is proposed to compute the optimal solutions numerically. A low-complexity suboptimal allocation algorithm is also presented. Simulation experiments are conducted to evaluate the performance of the proposed algorithms in terms of service outage probability and achievable transmission rate pairs for DC and NDC traffic.\",\n \"Title: Trellis-Coded Differential Unitary Space-Time Modulation In Slow Flat Fading Channels With Interleaver\\nYear: 2002\\n\\nAbstract: This paper considers trellis-coded differential unitary space-time modulation for multiple-antenna systems when neither the transmitter nor the receiver has access to channel state information. The channel is assumed to be slowly time-varying flat Rayleigh fading with ideal interleaver. We derive the metric for maximum likelihood differential decoding and the Chernoff bound for pair-wise error probability. We show that performance is dominated by the minimum Hamming distance which contributes linearly to the order of diversity. Code construction is described for rate m/(m + 1) trellis codes. Several code examples are provided based on diagonal cyclic group constellations for two transmit antennas with data rate 1 and 2 bits/s/Hz. Simulation results show that the proposed trellis-coded differential scheme can achieve high data rate communications by medium signal-to-noise ratio without channel estimation.\",\n \"Title: Exploiting hop diversity with frequency sharing in multi-hop OFDM networks\\nYear: 2009\\n\\nAbstract: We present a framework of frequency sharing in multi-hop OFDM networks. It enables simultaneous transmission of multiple hops without causing inter-hop interference. Hop diversity can then be achieved by exploiting channel frequency selectivity across active hops. Under the framework, we formulate a joint optimization problem of sub-channel assignment, power allocation, and time control. The proposed scheme is shown to achieve significantly higher spectral efficiency than hop-by-hop transmission. It also avoids the interference limiting issue incurred in full spatial reuse schemes.\",\n \"Title: Rotating Decode-and-Forward for Two Pairs of Two-Way Communications\\nYear: 2010\\n\\nAbstract: We study the transmission strategy for a system consisting of two pairs of two-way communication links. The information exchange between the two nodes in each pair can only occur with the help of the nodes in the other pair. A novel transmission protocol, named Rotating Decode-and-Forward (RDF) is proposed. In this protocol, the two pairs take turns to forward the signal for each other while having their own information embedded in the signal-to-forward by applying physical layer network coding. The achievable rate region of this protocol is derived. Numerical examples show that proposed RDF protocol can provide significantly higher spectral efficiency than conventional protocols where the transmissions of information signal and signal-to-forward are carried out separately.\",\n \"Title: Joint Source and Relay Precoding Designs for MIMO Two-Way Relaying Based on MSE Criterion\\nYear: 2011\\n\\nAbstract: Properly designed precoders can significantly improve the spectral efficiency of multiple-input multiple-output (MIMO) relay systems. In this paper, we investigate joint source and relay precoding design based on the mean-square-error (MSE) criterion in MIMO two-way relay systems, where two multiantenna source nodes exchange information via a multiantenna amplify-and-forward relay node. This problem is non-convex and its optimal solution remains unsolved. Aiming to find an efficient way to solve the problem, we first decouple the primal problem into three tractable subproblems, and then propose an iterative precoding design algorithm based on alternating optimization. The solution to each subproblem is optimal and unique, thus the convergence of the iterative algorithm is guaranteed. Second, we propose a structured precoding design to lower the computational complexity. The proposed precoding structure is able to parallelize the channels in the multiple access (MAC) phase and broadcast (BC) phase. It thus reduces the precoding design to a simple power allocation problem. Last, for the special case where only a single data stream is transmitted from each source node, we present a source-antenna-selection (SAS)-based precoding design algorithm. This algorithm selects only one antenna for transmission from each source and thus requires lower signalling overhead. Comprehensive simulation is conducted to evaluate the effectiveness of all the proposed precoding designs.\",\n \"Title: Power and Subcarrier Allocation for Physical-Layer Security in OFDMA Networks\\nYear: 2011\\n\\nAbstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink OFDMA-based broadband network with coexistence of secure users (SU) and normal users (NU). The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NU's while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NU's follows the conventional water-filling principle, the power allocation for SU's depends on both its own channel gain and the largest channel gain among others. We also design a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU's and secrecy rate for SU at different power consumptions.\",\n \"Title: An Auction Approach to Distributed Power Allocation for Multiuser Cooperative Networks\\nYear: 2012\\n\\nAbstract: This paper studies a wireless network where multiple users cooperate with each other to improve the overall network performance. Our goal is to design an optimal distributed power allocation algorithm that enables user cooperation, in particular, to guide each user on the decision of transmission mode selection and relay selection. Our algorithm has the nice interpretation of an auction mechanism with multiple auctioneers and multiple bidders. Specifically, in our proposed framework, each user acts as both an auctioneer (seller) and a bidder (buyer). Each auctioneer determines its trading price and allocates power to bidders, and each bidder chooses the demand from each auctioneer. By following the proposed distributed algorithm, each user determines how much power to reserve for its own transmission, how much power to purchase from other users, and how much power to contribute for relaying the signals of others. We derive the optimal bidding and pricing strategies that maximize the weighted sum rates of the users. Extensive simulations are carried out to verify our proposed approach.\",\n \"Title: Massive MIMO Multicasting in Noncooperative Cellular Networks\\nYear: 2013\\n\\nAbstract: We study physical layer multicasting in cellular networks where each base station (BS) is equipped with a very large number of antennas and transmits a common message using a single beamformer to multiple mobile users. The messages sent by different BSs are independent, and the BSs do not cooperate. We first show that when each BS knows the perfect channel state information (CSI) of its own served users, the asymptotically optimal beamformer at each BS is a linear combination of the channel vectors of its multicast users. Moreover, the optimal and explicit combining coefficients are obtained. Then we consider the imperfect CSI scenario where the CSI is obtained through uplink channel estimation in time-division duplex systems. We propose a new pilot scheme that estimates the composite channel, which is a linear combination of the individual channels of multicast users in each cell. This scheme is able to completely eliminate pilot contamination. The pilot power control for optimizing the multicast beamformer at each BS is also derived. Numerical results show that the asymptotic performance of the proposed scheme is close to the ideal case with perfect CSI. Simulation also verifies the effectiveness of the proposed scheme with finite number of antennas at each BS.\",\n \"Title: Time Sharing Policy in Wireless Networks for Variable Rate Transmission\\nYear: 2007\\n\\nAbstract: For most of wireless services with variable rate transmission, both average rate and rate oscillation are important performance metrics. One often needs to decide how much rate oscillation the service can tolerate to obtain a higher average rate. Service satisfaction for each user is quantified by an increasing and concave utility function of instantaneous transmission rate. It is capable of facilitating the resource allocation with flexible combinations of average rate and rate oscillation. Particularly, we are interested in maximizing the time-average aggregate utility by scheduling user transmissions in a time-shared wireless network. A resource allocation policy is developed, namely, time sharing (TS), to exploit the concavity of utility function and the fluctuation of channel gain. This is formulated as a constrained convex optimization problem. Our analysis shows that in the TS policy the optimal scheduler allows multiple users with relatively better channel conditions to share a same time frame in an adaptive time-division manner. In addition, the more concave the utility function is, the higher the probability of time frame sharing is. An extension to quantized time sharing with limited channel feedback (QTSL) for practical systems is all studied. Simulation results show that, two to three bits of channel state information (CSI) are sufficient for the performance of QTSL scheme to approach that of the optimal TS policy when the number of time slots in a time frame is not less than the number of users, especially, in high SNR region.\",\n \"Title: A Generalized Gradient Scheduling Algorithm in Wireless Networks for Variable Rate Transmission\\nYear: 2007\\n\\nAbstract: Average transmission rate and rate oscillation are two important performance metrics for most wireless services. Both are often needed to be optimized in multi-user scheduling and resource management. In this paper we introduce a utility function that increases with average rate but decreases with rate variance. It is capable of facilitating resource allocation with flexible combinations of the two performance metrics. A generalized gradient scheduling algorithm (GGSA) is then developed to maximize the proposed utility. It is shown that the best scheduler should maximize the sum of concave functions of instantaneous transmission rates in order to maximize the utility of average rate and rate oscillation. The scheduler reduces to the traditional gradient scheduling algorithm when the rate variance term in the new utility function is omitted. We analyze the dynamics of average transmission rates and rate variances using ordinary differential equation and show that GGSA is asymptotically optimal under the condition that the transmission rate vector, after an appropriate scaling, converges to a fixed vector as time goes into infinity.\",\n \"Title: Superimposed XOR: Approaching Capacity Bounds of the Two-Way Relay Channels\\nYear: 2010\\n\\nAbstract: In two-way relay channels, bitwise XOR and symbol-level superposition coding\\nare two popular network-coding based relaying schemes. However, neither of them\\ncan approach the capacity bound when the channels in the broadcast phase are\\nasymmetric. In this paper, we present a new physical layer network coding\\n(PLNC) scheme, called \\\\emph{superimposed XOR}. The new scheme advances the\\nexisting schemes by specifically taking into account the channel asymmetry as\\nwell as information asymmetry in the broadcast phase. We obtain its achievable\\nrate regions over Gaussian channels when integrated with two known time control\\nprotocols in two-way relaying. We also demonstrate their average maximum\\nsum-rates and service delay performances over fading channels. Numerical\\nresults show that the proposed superimposed XOR achieves a larger rate region\\nthan both XOR and superposition and performs much better over fading channels.\\nWe further deduce the boundary of its achievable rate region of the broadcast\\nphase in an explicit and analytical expression. Based on these results, we then\\nshow that the gap to the capacity bound approaches zero at high signal-to-noise\\nratio.\",\n \"Title: Relay Placement for Physical Layer Security: A Secure Connection Perspective\\nYear: 2012\\n\\nAbstract: This work studies the problem of secure connection in cooperative wireless communication with two relay strategies, decode-and-forward (DF) and randomize-and-forward (RF). The four-node scenario and cellular scenario are considered. For the typical four-node (source, destination, relay, and eavesdropper) scenario, we derive the optimal power allocation for the DF strategy and find that the RF strategy is always better than the DF to enhance secure connection. In cellular networks, we show that without relay, it is difficult to establish secure connections from the base station to the cell edge users. The effect of relay placement for the cell edge users is demonstrated by simulation. For both scenarios, we find that the benefit of relay transmission increases when path loss becomes severer. © 2012 IEEE.\",\n \"Title: Robust Relay Beamforming for Two-Way Relay Networks.\\nYear: 2012\\n\\nAbstract: We study the design of robust relay beamforming for two-way relay networks by considering channel feedback errors. Our objective is to maximize the minimum worst-case signal-to-noise ratios (SNRs) of two sources subject to a total relay power budget. We first decompose this non-convex problem into a series of relay power minimization problems under minimum SNR constraints by using bisection search. Then the relay power minimization problem is recast to a semidefinite programming relaxation (SDR) problem. A suboptimal but efficient solution is finally obtained for the original design. A necessary condition for the power minimization problem to be feasible is also given. For the special case with perfect channel state information, an alternative algorithm is introduced to find the optimal beamformer, which has lower complexity than the existing method. © 2012 IEEE.\",\n \"Title: QoS-aware policies for OFDM bidirectional transmission with decode-and-forward relaying\\nYear: 2012\\n\\nAbstract: In this paper, we consider the orthogonal frequency division multiplexing (OFDM)-based bidirectional transmission where a pair of users exchange information with the assistance of a decode-and-forward (DF) relay. Each user can communicate with the other via three transmission modes: direct transmission, one-way relaying, and two-way relaying. We jointly optimize the transmission policies, including power allocation, transmission mode selection, and subcarrier-node assignment for maximizing the weighted sum rates of the two users with quality-of-service (QoS) guarantees. We formulate the joint optimization problem as a mixed integer programming problem. By using the dual method, we solve the problem efficiently in an asymptotically optimal manner. Particularly, we derive the capacity region of two-way DF relaying in parallel relay channels. Simulation results show that the proposed resource-allocation scheme can substantially improve system performance compared with the conventional schemes.\",\n \"Title: Analysis of Differential Orthogonal Space-Time Block Codes Over Semi-Identical MIMO Fading Channels\\nYear: 2006\\n\\nAbstract: We study the performance of differential orthogonal space-time block codes (OSTBC) over independent and semi-identically distributed block Rayleigh fading channels. In this semiidentical fading model, the channel gains from different transmit antennas to a common receive antenna are identically distributed, but the gains associated with different receive antennas are nonidentically distributed. Ar...\",\n \"Title: End-to-End Resource Allocation in OFDM Based Linear Multi-Hop Networks\\nYear: 2008\\n\\nAbstract: We study the end-to-end resource allocation in an OFDM based multi-hop network consisting of a one-dimensional chain of nodes including a source, a destination, and multiple relays. The problem is to maximize the end-to-end average transmission rate under a long-term total power constraint by adapting the transmission power on each subcarrier over each hop and the transmission time used by each hop in every time frame. The solution to the problem is derived by decomposing it into two subproblems: short-term time and power allocation given an arbitrary total power constraint for each channel realization, and total power distribution over all channel realizations. We show that the optimal solution has the following features: the power allocation on subcarriers over each hop has the water-filling structure and a higher water level is given to the hop with relatively poor channel condition; meanwhile, the fraction of transmission time allocated to each hop is adjusted to keep the instantaneous rates over all hops equal. To tradeoff between performance, computational complexity and signalling overhead, three suboptimal resource allocation algorithms are also proposed. Numerical results are illustrated under different network settings and channel environments.\",\n \"Title: Power and Subcarrier Allocation for Physical-Layer Security in OFDMA-Based Broadband Wireless Networks\\nYear: 2011\\n\\nAbstract: Providing physical-layer security for mobile users in future broadband wireless networks is of both theoretical and practical importance. In this paper, we formulate an analytical framework for resource allocation in a downlink orthogonal frequency-division multiple access (OFDMA)-based broadband network with coexistence of secure users (SUs) and normal users (NUs). The SUs require secure data transmission at the physical layer while the NUs are served with conventional best-effort data traffic. The problem is formulated as joint power and subcarrier allocation with the objective of maximizing average aggregate information rate of all NUs while maintaining an average secrecy rate for each individual SU under a total transmit power constraint for the base station. We solve this problem in an asymptotically optimal manner using dual decomposition. Our analysis shows that an SU becomes a candidate competing for a subcarrier only if its channel gain on this subcarrier is the largest among all and exceeds the second largest by a certain threshold. Furthermore, while the power allocation for NUs follows the conventional water-filling principle, the power allocation for SUs depends on both its own channel gain and the largest channel gain among others. We also develop a suboptimal algorithm to reduce the computational cost. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of the achievable pair of information rate for NU and secrecy rate for SU at different power consumptions.\",\n \"Title: Subcarrier-pair based resource allocation for cooperative multi-relay OFDM systems\\nYear: 2010\\n\\nAbstract: In this paper, we study the joint allocation of three types of resources, namely, power, subcarriers and relay nodes, in multi-relay assisted dual-hop cooperative OFDM systems. All the relays adopt the amplify-and-forward protocol and assist the transmission from the source to destination simultaneously but on orthogonal subcarriers. The objective is to maximize the system transmission rate subject to individual power constraints on each node or a total network power constraint. We formulate such a problem as a subcarrier-pair based resource allocation that seeks the joint optimization of subcarrier pairing, subcarrier-pair-to-relay assignment, and power allocation. Using a dual approach, we solve this problem efficiently in an asymptotically optimal manner. Specifically, for the optimization problem with individual power constraints, the computational complexity is polynomial in the number of subcarriers and relay nodes, whereas the complexity of the problem with a total power constraint is polynomial in the number of subcarriers.We further propose two suboptimal algorithms for the former to trade off performance for complexity. Simulation studies are conducted to evaluate the average transmission rate and outage probability of the proposed algorithms. The impact of relay location is also discussed.\",\n \"Title: Cooperative secret communication with artificial noise in symmetric interference channel\\nYear: 2010\\n\\nAbstract: We consider the symmetric Gaussian interference channel where two users try to enhance their secrecy rates in a cooperative manner. Artificial noise is introduced along with useful information. We derive the power control and artificial noise parameter for two kinds of optimal points, max-min point and single user point. It is shown that there exists a critical value Pc of the power constraint, below which the max-min point is an optimal point on the secrecy rate region, and above which time-sharing between single user points achieves larger secrecy rate pairs. It is also shown that artificial noise can help to enlarge the secrecy rate region, in particular on the single user point.\",\n \"Title: Optimal Linear Transceiver Designs for Cognitive Two-Way Relay Networks\\nYear: 2013\\n\\nAbstract: This paper studies a cooperative cognitive radio network where two primary users (PUs) exchange information with the help of a secondary user (SU) that is equipped with multiple antennas and in return, the SU superimposes its own messages along with the primary transmission. The fundamental problem in the considered network is the design of transmission strategies at the secondary node. It involves three basic elements: first, how to split the power for relaying the primary signals and for transmitting the secondary signals; second, what two-way relay strategy should be used to assist the bidirectional communication between the two PUs; third, how to jointly design the primary and secondary transmit precoders. This work aims to address this problem by proposing a transmission framework of maximizing the achievable rate of the SU while maintaining the rate requirements of the two PUs. Three well-known and practical two-way relay strategies are considered: amplify-and-forward (AF), bit level XOR based decode-and-forward (DF-XOR) and symbol level superposition coding based DF (DF-SUP). For each relay strategy, although the design problem is non-convex, we find the optimal solution by using certain transformation techniques and optimization tools such as semidefinite programming (SDP) and second-order cone programming (SOCP). Closed-form solutions are also obtained under certain conditions. Simulation results show that when the rate requirements of the two PUs are symmetric, by using the DF-XOR strategy and applying the proposed optimal precoding, the SU requires the least power for relaying and thus reserves the most power to transmit its own signal. In the asymmetric scenario, on the other hand, the DF-SUP strategy with the corresponding optimal precoding is the best.\",\n \"Title: Distributed sparse channel estimation for OFDM systems with high mobility\\nYear: 2013\\n\\nAbstract: Channel estimation for an orthogonal frequency-division multiplexing (OFDM) broadband system operating with high mobility is very challenging. This is mainly due to the significant Doppler spread, inherent in a time-frequency doubly-selective (DS) channel. Consequently, a large number of channel coefficients must be estimated, forcing the need for allocating a large number of pilot subcarriers. To address this problem, we propose a novel channel estimation method based on basis expansion models (BEMs) and distributed compressive sensing (DCS) theory. To be specific, we develop a two-stage sparse BEM coefficients estimation method, which can effectively combat the Doppler spread and enable accurate channel estimation with dramatically reduced number of pilot subcarriers. The numerical results reveal that, in a typical LTE system configuration, the proposed scheme can increase the spectral efficiency by 40% and achieve a 6 dB gain in terms of normalized mean square error (NMSE), both compared to the conventional scheme.\",\n \"Title: End-to-end outage minimization in OFDM based linear relay networks\\nYear: 2009\\n\\nAbstract: Multi-hop relaying is an economically efficient architecture for coverage extension and throughput enhancement in future wireless networks. OFDM, on the other hand, is a spectrally efficient physical layer modulation technique for broadband transmission. As a natural consequence of combining OFDM with multi-hop relaying, the allocation of perhop subcarrier power and per-hop transmission time is crucial in optimizing the network performance. This paper is concerned with the end-to-end information outage in an OFDM based linear relay network. Our goal is to find an optimal power and time adaptation policy to minimize the outage probability under a long-term total power constraint. We solve the problem in two steps. First, for any given channel realization, we derive the minimum short-term power required to meet a target transmission rate. We show that it can be obtained through two nested bisection loops. To reduce computational complexity and signalling overhead, we also propose a sub-optimal algorithm. In the second step, we determine a power threshold to control the transmission on-off so that the long-term total power constraint is satisfied. Numerical examples are provided to illustrate the performance of the proposed power and time adaptation schemes with respect to other resource adaptation schemes.\",\n \"Title: V-OFDM: On Performance Limits over Multi-Path Rayleigh Fading Channels\\nYear: 2011\\n\\nAbstract: As a bridge of connecting orthogonal frequency division multiplexing (OFDM) with single-carrier frequency domain equalization (SC-FDE) techniques, Vector OFDM (V-OFDM) provides significant flexibility in system design. This paper presents an analytical study of V-OFDM over multi-path fading channels. Our goal is to investigate the diversity gain and coding gain of each vector block (VB) in V-OFDM so as to ultimately reveal its performance limits over fading channel. By using algebraic number theory tools, we rigorously prove for the first time that a majority of VBs in V-OFDM can surely realize the diversity gain of min {M,G} , where M is the length of each VB, and G is the total number of channel taps. Furthermore, some specific VBs, whose length equals the total number of channel taps, can not only harvest the maximum diversity gain but also achieve the maximum coding gain. It is further demonstrated that, even though VBs fail to benefit from additional diversity gain when M exceeds G, they can enjoy significantly increased coding gains. Our analysis concludes that it is preferable to choose the length of VBs to be equal to the number of channel taps in consideration of both overall system performance and computational complexity.\",\n \"Title: Precoding Strategy Selection for Cognitive MIMO Multiple Access Channels Using Learning Automata\\nYear: 2010\\n\\nAbstract: In this paper, we study the quantized precoding strategy selection for multiple-input multiple-output (MIMO) multiple access channels (MAC) in cognitive radio (CR) networks through a game-theoretic perspective. Since the secondary users in such system are difficult to be coordinated by a centralized authority, they are noncooperative and attempt to maximize their own payoffs selfishly in a distributed method. We propose a noncooperative precoding strategy selection game and find that it is a potential game which possesses at least one pure strategy Nash equilibrium. A decentralized learning algorithm with a small amount of feedback is proposed to obtain Nash equilibrium. We prove that the proposed algorithm can converge to a pure strategy Nash equilibrium. Simulation results are provided to verify our analysis.\",\n \"Title: An efficient beamforming scheme for generalized MIMO two-way X relay channels\\nYear: 2013\\n\\nAbstract: Recently, a multiple-input multiple-output (MIMO) two-way X relay channel, where two groups of source nodes each having 2 nodes exchange independent messages via a common relay node, was studied in [1]. In this paper, we extend it to the generalized MIMO two-way X relay channel, where m ≥ 2 and n ≥ 2 source nodes are contained in two groups, respectively. Based on signal space alignment, a new beamforming scheme is proposed to maximize the minimum effective signal to interference plus noise ratios (SINRs) among all data streams. The beamforming vectors are designed by an iterative algorithm in which a closed-form solution is obtained in each step. Moreover, we show that the power allocation problem given the shape of the beamformers can be transformed as a linear programming problem. Simulation results show that the proposed beamforming scheme can achieve significantly better error performance than random beamforming schemes subject to signal space alignment only.\",\n \"Title: The New Interference Alignment Scheme for the MIMO Interference Channel\\nYear: 2010\\n\\nAbstract: In this paper, we propose a new interference alignment (IA) scheme designing jointly the linear transmitter and receiver for the MIMO interference channel system, using minimum total mean square error criterion, subject to individual transmit power constraints. We show that transmitter and receiver under such criterion could be realized through a joint iterative algorithm. The convergence of the proposed algorithm is discussed. We also proposed a robust MMSE-based iterative design with imperfect channel state information (CSI). The proposed robust MMSE-based iterative interference alignment scheme is shown to be less sensitive to channel estimation errors. Simulation results show that the proposed schemes outperform the existing IA schemes with fast convergence.\",\n \"Title: Closed-Form Performance Of Mfsk Signals With Diversity Reception Over Non-Identical Fading Channels\\nYear: 2007\\n\\nAbstract: This paper provides a comprehensive study on the error performance of noncoherent orthogonal M-ary frequency shift-keying (FSK) signals with various diversity combining schemes over fading channels. The diversity branches are assumed to be independent and non-identically distributed (i.n.d) Rayleigh fading. Closed-form expressions for the symbol error probability with an arbitrary diversity order and any modulation level are obtained for optimal combining (OC), equal gain combining (EGC) and log-likelihood ratio based selection combining (SC-LLR). Our analytical results show that EGC performs closely to OC over slightly unbalanced channels, whereas for highly unbalanced channels SC-LLR performs more closely to OC than EGC.\",\n \"Title: Coordinated beamforming design in multicell multicast networks\\nYear: 2012\\n\\nAbstract: In this paper, we study the physical layer multicasting in multicell networks, where each base station equipped with multiple antennas transmits a common message using a single beamformer to multiple users equipped with a single antenna in the same cell. We consider the quality-of-service (QoS) beamforming for minimizing the total power consumption while guaranteeing that the signal-to-interference-plus-noise ratio (SINR) at each user is above a predetermined threshold. Based on the decomposition theory, we propose a novel decentralized algorithm to implement the coordinated beamforming with limited information sharing among different base stations. The algorithm is guaranteed to converge and in most cases it converges to the optimal solution. Simulation results demonstrate significant advantages of the proposed coordinated beamforming over conventional beamforming.\",\n \"Title: Pairwise Check Decoding for LDPC Coded Two-Way Relay Block Fading Channels.\\nYear: 2012\\n\\nAbstract: Partial decoding has the potential to achieve a larger capacity region than full decoding in two-way relay (TWR) channels. Existing partial decoding realizations are however designed for Gaussian channels and with a static physical layer network coding (PLNC). In this paper, we propose a new solution for joint network coding and channel decoding at the relay, called pairwise check decoding (PCD), ...\",\n \"Title: Capacity Analysis and Power Allocation over Non-Identical MISO Rayleigh Fading Channels\\nYear: 2008\\n\\nAbstract: We analyze the capacity of a multiple-input single- output system over Rayleigh fading channels. The channels are assumed to be independent and non-identically distributed. Simple, explicit and closed-form expressions of ergodic mutual information and outage probability are obtained. Moreover, two suboptimal but efficient analytical power allocation schemes for mutual information maximization and outage minimization are derived, respectively. In specific, for mutual information maximization, more power is assigned to those channels with higher channel variances, while for outage minimization the power allocation scheme follows the water-filling principle.\",\n \"Title: Trellis-coded differential unitary space-time modulation over flat fading channels\\nYear: 2003\\n\\nAbstract: Coding and modulation for multiple-antenna systems have gained much attention in wireless communications. This paper investigates a noncoherent trellis-coded scheme based on differential unitary space-time modulation when neither the transmitter nor the receiver know the channel. In a time-varying flat Rayleigh fading environment, we derive differentially noncoherent decision metrics and obtain performance measures for systems with either an ideal interleaver or no interleaver. We demonstrate that with an ideal interleaver, the system performance is dominated by the minimum Hamming distance of the trellis code, while without an interleaver, the performance is dominated by the minimum free squared determinant distance (a novel generalization of the Euclidean distance) of the code. For both cases, code construction is described for Ungerboeck-type codes. Several examples that are based on diagonal cyclic group constellations and offer a good tradeoff between the coding advantage and trellis complexity are provided. Simulation results show that, by applying the soft-decision Viterbi decoder, the proposed scheme can achieve very good performance even with few receive antennas. Extensions to trellis-coded differential space-time block codes are also discussed.\",\n \"Title: Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems\\nYear: 2008\\n\\nAbstract: Most existing work on adaptive allocation of sub- carriers and power in multiuser orthogonal frequency division multiplexing (OFDM) systems has focused on homogeneous traffic consisting solely of either delay-constrained data (guaranteed service) or non-delay-constrained data (best-effort service). In this paper, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and non-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the users with DC traffic under a total transmit power constraint. Through our analysis we show that the optimal power allocation over subcarriers follows a multi-level water-filling principle; moreover, the valid candidates competing for each subcarrier include only one NDC user but all DC users. By converting this combinatorial problem with exponential complexity into a convex problem or showing that it can be solved in the dual domain, efficient iterative algorithms are proposed to find the optimal solutions. To further reduce the computational cost, a low-complexity suboptimal algorithm is also developed. Numerical studies are conducted to evaluate the performance of the proposed algorithms in terms of service outage probability, achievable transmission rate pairs for DC and NDC traffic, and multiuser diversity.\",\n \"Title: Extended Space-Time Block Coding with Transmit Antenna Selection over Correlated Fading Channels\\nYear: 2007\\n\\nAbstract: A new space-time block coded transmit antenna selection scheme over spatially correlated fading channels is presented. This scheme allows two or more transmit antennas to simultaneously use one radio frequency frontend. A system with four transmit antennas is considered in particular. The four antennas are selectively grouped into two subsets. Alamouti code is then applied on top of the subsets as if each was a single antenna. This scheme is shown to be more efficient than the conventional transmit antenna selection combined with Alamouti code in correlated channels. Moreover, it lowers the bitrate of the feedback channel.\",\n \"Title: Outage performance analysis of two-way relay system with multi-antenna relay node\\nYear: 2012\\n\\nAbstract: This paper presents an analytical study on the outage performance of amplify-and-forward (AF) two-way relay system with multi-antenna relay node (RN). Two major bidirectional protocols, i.e., two time slots multiple access broadcast (MABC) protocol and three time slots time division broadcast (TDBC) protocol, are considered. For both considerations, we first assume that instantaneous channel-state-information (CSI) is unavailable at RN, thus RN just simply uses the fixed relay gain derived from statistical CSI to scale the received signals before forwarding. We then consider the scenario where RN can obtain the instantaneous CSI to perform the zero-forcing (ZF) relay precoding. The closed-form expressions of outage probability are derived for all cases. Based on these expressions, the diversity-multiplexing tradeoff (DMT) is further obtained for the MABC protocol. The analytical results show that, for non-precoding MABC scheme, the diversity order is only 1, which is independent to the relay antenna number M. While for the ZF-precoding case, the diversity order of M - 1 can be obtained.\",\n \"Title: MSE-based transceiver designs for the MIMO interference channel\\nYear: 2010\\n\\nAbstract: Interference alignment (IA) has evolved as a powerful technique in the information theoretic framework for achieving the optimal degrees of freedom of interference channel. In practical systems, the design of specific interference alignment schemes is subject to various criteria and constraints. In this paper, we propose novel transceiver schemes for the MIMO interference channel based on the mean square error (MSE) criterion. Our objective is to optimize the system performance under a given and feasible degree of freedom. Both the total MSE and the maximum per-user MSE are chosen to be the objective functions to minimize. We show that the joint design of transmit precoding matrices and receiving filter matrices with both objectives can be realized through efficient iterative algorithms. The convergence of the proposed algorithms is proven as well. Simulation results show that the proposed schemes outperform the existing IA schemes in terms of BER performance. Considering the imperfection of channel state information (CSI), we also extend the MSE-based transceiver schemes for the MIMO interference channel with CSI estimation error. The robustness of the proposed algorithms is confirmed by simulations.\",\n \"Title: Improved design criteria and new trellis codes for space-time coded modulation in slow flat fading channels\\nYear: 2001\\n\\nAbstract: The design criteria for space-time codes under slow flat Rayleigh fading environments are well known to be the rank criterion and the determinant criterion. However, the derivation of these two criteria is based on the assumption that the signal-to-noise ratio (SNR) is sufficiently high. Hence these criteria are loose when the SNR does not satisfy this assumption. In this letter, we consider this practical issue and derive tighter design criteria for moderate and low SNRs. Some new space-time trellis codes are found based on the new criteria through computer search. Simulation results show that these codes outperform existing codes under their designed SNR conditions.\",\n \"Title: End-to-End Outage Probability Minimization in OFDM Based Linear Multi-Hop Networks\\nYear: 2008\\n\\nAbstract: This paper is concerned with the end-to-end transmission outage in an OFDM based wireless multi-hop network. The network consists of a source node, a destination node, and a set of serial relay nodes. Transmission outage occurs when the end-to-end transmission rate is less than a target rate. Our goal is to find an optimal power and time control policy to minimize the outage probability at a target end-to-end data rate under a long-term total power constraint. The problem is solved in two steps. First, for any given channel realization, we derive the minimum total power required to meet the target rate by varying the transmission power and time allocated to each hop. This is formulated as a convex optimization problem and is solved efficiently. We then compare the required minimum total power for each channel realization with a power threshold. If the threshold is exceeded, the transmission is turned off. The optimal threshold is chosen to meet the long-term total power constraint. Two suboptimal power and time control policies are also presented and compared with the optimal policy by simulation.\",\n \"Title: Joint scheduling and relay selection in one- and two-way relay networks with buffering\\nYear: 2009\\n\\nAbstract: In most wireless relay networks, the source and relay nodes transmit successively via fixed time division (FTD) and each relay forwards a packet immediately upon receiving. In this paper we enable the buffering capability of relay nodes and propose a framework for joint scheduling and relay selection. The goal is to maximize the system long-term throughput by fully exploiting multi-user diversity in the network. We develop two joint scheduling and relay selection (JSRS) algorithms for unidirectional and bidirectional traffic, respectively. The novel cross-layer relay selection metrics which our algorithms are based upon take into account both instantaneous channel conditions and the queuing status. We also demonstrate that the proposed JSRS can be realized in a distributed way without explicit coordination among the network nodes. Extensive simulation is carried out to evaluate the performance of the proposed JSRS with buffering in comparison with traditional FTD without buffering. Typical throughput enhancements up to 101% and 110% are observed in one-way and two-way relay networks respectively, at low signal-to-noise ratio (0 dB).\",\n \"Title: On Degrees of Freedom of Cognitive Networks with User Cooperation.\\nYear: 2012\\n\\nAbstract: In this letter, the degrees of freedom (DoF) outer bound is characterized for cognitive networks. We have devised an interference alignment scheme with appropriate cooperation between primary users and secondary users to achieve the DoF outer bound. Moreover, to encourage the primary users to participate in the proposed cooperation, we also design two aided interference alignment schemes, where bo...\",\n \"Title: Resource Allocation in Open Access OFDMA Femtocell Networks\\nYear: 2012\\n\\nAbstract: Open access is an efficient approach to reduce cross-tier interference in femtocell networks. In this paper, we study resource allocation in open access OFDMA femtocell networks to guarantee QoS of the neighboring macrocell user (MU) in Dead Zone and limit cross-tier interference to other MUs. A new resource allocation method is proposed to improve performance of both neighboring MU and femtocell users (FU). In specific, the subchannel set originally assigned to the MU may overlap the subchannel set occupied by FAP and cause cross-tier interference. The overlapped subchannel set is freed by macro base station (MBS) after MU resigns and joins the nearby femtocell. Then the subchannel and power resources in the femtocell are re-allocated. We leverage cognitive radio (CR) technology in femtocell networks and propose an asymptotically optimal resource allocation algorithm using dual decomposition methods. Simulation results show that the proposed algorithm for the open access scheme can achieve higher transmission rate in contrast to the closed access scheme.\",\n \"Title: An Estimation Algorithm Of Channel State Transition Probabilities For Cognitive Radio Systems\\nYear: 2008\\n\\nAbstract: In this paper, an estimation algorithm of channel state transition probabilities in Markov channel model for cognitive radio systems is proposed. The framework of POMDP is adopted to solve the problem of channel selection. Maximum likelihood method is used to estimate the channel state transition probabilities, which is crucial to POMDP. Central Limit Theorem is introduced to get the relationship between the precision, sample times and the channel state transition probability values. The simulation results show the reliability of the estimation results.\",\n \"Title: A spectrum access game in bidirectional cognitive relay networks\\nYear: 2010\\n\\nAbstract: We consider a cognitive relay network where two secondary users can access the unutilized spectrum and conduct bidirectional communication via the help of primary users. The primary users are regarded as relay nodes of the secondary users and adopt amplify-and-forward relaying strategy. Physical-layer network coding is used when both secondary users select the same relay. The spectrum access problem in the considered system model is defined as joint relay selection and discrete power control. We formulate the problem as a noncooperative game where the players are the secondary users and the common payoff function takes both transmission rate and power consumption into account. The proposed game falls into the framework of potential games where at least one pure strategy Nash equilibrium (NE) exists. Furthermore, the social optimal solution is also a pure strategy NE of the proposed game. We then propose a distributed algorithm based on learning automata to achieve the pure strategy NE. Numerical results show that the proposed algorithm has good convergence and near optimal performance.\",\n \"Title: Degrees of Freedom of MIMO Multiway Relay Channel With Clustered Pairwise Exchange\\nYear: 2015\\n\\nAbstract: In this paper, we consider a symmetric multiple-input-multiple-output (MIMO) multiway relay channel (mRC) with L clusters and K users per cluster operating in clustered pairwise data exchange. Each user is equipped with M antennas, and the relay is equipped with N antennas. The degrees of freedom (DoF) of the MIMO mRC has recently attracted much research interest. The DoF results under certain configurations of (L,K,M,N) have been reported. However, the DoF capacity of the MIMO mRC with an arbitrary network configuration is, in general, far from being well understood. In this regard, the main contribution of this paper is to propose a systematic signal alignment approach to jointly design the beamforming matrices at the users and the relay. Based on that, an achievable DoF is derived for the MIMO mRC with an arbitrary network configuration of (L,K,M,N). Our analysis revealed that the derived achievable DoF is piecewise linear in M and N alternately. Moreover, we showed that the DoF capacity can be achieved for M/N ∈ [1/LK(K-1) + 1/2, ∞) and M/N ∈ (0, Lq/LK(Lq-1)], where q = 2 ⌈K/2⌉.We further derived the asymptotic DoF as K or L → ∞. The DoF analysis in this paper can provide insights on the practical design of efficient communication mechanisms over multiterminal MIMO relay networks.\",\n \"Title: Generalized Signal Alignment: On the Achievable DoF for Multi-User MIMO Two-Way Relay Channels\\nYear: 2015\\n\\nAbstract: This paper studies the achievable degrees of freedom (DoF) for multi-user multiple-input multiple-output (MIMO) two-way relay channels, where there are K source nodes, each equipped with M antennas, one relay node, equipped with N antennas, and each source node exchanges independent messages with an arbitrary set of other source nodes via the relay. By allowing an arbitrary information exchange pattern, the considered channel model is a unified one. It includes several existing channel models as special cases: K-user MIMO Y channel, multipair MIMO two-way relay channel, generalized MIMO two-way X relay channel, and L-cluster MIMO multiway relay channel. Previous studies mainly considered the achievability of the DoF cut-set bound 2N at the antenna configuration N < 2M by applying signal alignment for network coding. This work aims to investigate the achievability of the DoF cut-set bound KM for the case N 2M. To this end, we first derive tighter DoF upper bounds for three special cases of the considered channel model. Then, we propose a new transmission framework, generalized signal alignment (GSA), to approach these bounds. The notion of GSA is to form network-coded symbols by aligning every pair of signals to be exchanged in a compressed subspace at the relay. A necessary and sufficient condition to construct the relay compression matrix is given. We show that using GSA, the new DoF upper bound is achievable when i) N M 2 ( 0; 2 + 4 K(K1) ] [ [ K 2;+1 ) for the K-user MIMO Y channel; ii) N M 2 ( 0; 2 + 4 K ] [ [ K 2;+1 ) for the multi-pair MIMO two-way relay channel; iii) N M 2 ( 0; 2+ 8 K2 ] [ [ K2;+1 ) for the generalized MIMO two-way X relay channel. We also provide the antenna configuration regions for the general multiuser MIMO two-way relay channel to achieve the total DoF KM.\",\n \"Title: Channel Estimation and Optimal Training Design for Correlated MIMO Two-Way Relay Systems in Colored Environment\\nYear: 2014\\n\\nAbstract: In this paper, while considering the impact of the antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcast (BC) phase. By considering the Kroneckerstructured channel model, we derive the optimal linear minimum mean-square-error (LMMSE) channel estimators. The corresponding training designs for the MAC phase and the BC phase are then formulated and solved to improve channel estimation accuracy. For the general scenario of the training sequence design for both phases, two iterative training design algorithms are proposed that are verified to produce training sequences achieving near optimal channel estimation performance. Furthermore, for specific practical scenarios, where the covariance matrices of the channel or disturbances are of particular structures, the optimal training sequence design guidelines are obtained. The minimum required training lengths for channel estimation in both the MAC phase and the BC phase are also analyzed. Comprehensive simulations are carried out to demonstrate the effectiveness of the proposed training designs.\",\n \"Title: Resource Allocation in Spectrum-Sharing OFDMA Femtocells With Heterogeneous Services\\nYear: 2014\\n\\nAbstract: Femtocells are being considered a promising technique to improve the capacity and coverage for indoor wireless users. However, the cross-tier interference in the spectrum-sharing deployment of femtocells can degrade the system performance seriously. The resource allocation problem in both the uplink and the downlink for two-tier networks comprising spectrum-sharing femtocells and macrocells is investigated. A resource allocation scheme for cochannel femtocells is proposed, aiming to maximize the capacity for both delay-sensitive users and delay-tolerant users subject to the delay-sensitive users' quality-of-service constraint and an interference constraint imposed by the macrocell. The subchannel and power allocation problem is modeled as a mixed-integer programming problem, and then, it is transformed into a convex optimization problem by relaxing subchannel sharing; finally, it is solved by the dual decomposition method. Subsequently, an iterative subchannel and power allocation algorithm considering heterogeneous services and cross-tier interference is proposed for the problem using the subgradient update. A practical low-complexity distributed subchannel and power allocation algorithm is developed to reduce the computational cost. The complexity of the proposed algorithms is analyzed, and the effectiveness of the proposed algorithms is verified by simulations.\",\n \"Title: A New DoF Upper Bound and Its Achievability for $K$-User MIMO Y Channels.\\nYear: 2014\\n\\nAbstract: This work is to study the degrees of freedom (DoF) for the $K$-user MIMO Y channel. Previously, two transmission frameworks have been proposed for the DoF analysis when $N \\\\geq 2M$, where $M$ and $N$ denote the number of antennas at each source node and the relay node respectively. The first method is named as signal group based alignment proposed by Hua et al. in [1]. The second is named as signal pattern approach introduced by Wang et al. in [2]. But both of them only studied certain antenna configurations. The maximum achievable DoF in the general case still remains unknown. In this work, we first derive a new upper bound of the DoF using the genie-aided approach. Then, we propose a more general transmission framework, generalized signal alignment (GSA), and show that the previous two methods are both special cases of GSA. With GSA, we prove that the new DoF upper bound is achievable when $\\\\frac{N}{M} \\\\in \\\\left(0,2+\\\\frac{4}{K(K-1)}\\\\right] \\\\cup \\\\left[K-2, +\\\\infty\\\\right)$. The DoF analysis in this paper provides a major step forward towards the fundamental capacity limit of the $K$-user MIMO Y channel. It also offers a new approach of integrating interference alignment with physical layer network coding.\",\n \"Title: Polar Coding for Secure Transmission in MISO Fading Wiretap Channels.\\nYear: 2014\\n\\nAbstract: In this paper, we propose a polar coding scheme for secure communication over the multiple-input, single-output, single-antenna eavesdropper (MISOSE) fading channel. We consider the case of block fading channels with known eavesdropper channel state information (CSI) and the case of fading channels with known eavesdropper channel distribution information (CDI). We use the artificial noise assisted secure precoding method to maximize the secrecy capacity in the first case, and to overcome the unawareness of the eavesdropper CSI in the second case. We show that our proposed scheme can provide both reliable and secure communication over the MISOSE channel with low encoding and decoding complexity.\",\n \"Title: On content-centric wireless delivery networks\\nYear: 2014\\n\\nAbstract: The flux of social media and the convenience of mobile connectivity have created a mobile data phenomenon that is expected to overwhelm mobile cellular networks in the foreseeable future. Despite the advent of 4G/LTE, the growth rate of wireless data has far exceeded the capacity increase of mobile networks. A fundamentally new design paradigm is required to tackle the ever growing wireless data challenge. In this article, we investigate the problem of massive content delivery over wireless networks, and present a systematic view of content-centric network design and its underlying challenges. Toward this end, we first review some of the recent advancements in information-centric networking, which provide the basis of how media contents can be labeled, distributed, and placed across the networks. We then formulate the content delivery task into a content rate maximization problem over a shared wireless channel, which, in contrast to the conventional wisdom that attempts to increase the bit rate of a unicast system, maximizes the content delivery capability with a fixed amount of wireless resources. This conceptually simple change enables us to exploit the content diversity and network diversity by leveraging the abundant computation sources (through application-layer encoding, pushing and caching, etc.) within the existing wireless networks. A network architecture that enables wireless network crowdsourcing for content delivery is then described, followed by an exemplary campus wireless network that encompasses the above concepts.\",\n \"Title: Graph theory and its applications to future network planning: software-defined online small cell management\\nYear: 2015\\n\\nAbstract: Network planning is facing new and critical challenges due to ad hoc deployment, unbalanced and drastically varying traffic demands, as well as limited backhaul and hardware resources in emerging small cell architectures. We discuss the application of graph theory to address the challenges. A clique-based software-defined online network management approach is proposed that captures traffic imbalance and fluctuation of small cells and optimally plans frequencies, infrastructures, and network structure at any instant. Its applications to three important small cell scenarios of cloud radio, point-to-point microwave backhaul, and interoperator spectrum sharing are demonstrated. Comparison studies show that in each of the scenarios, this new approach is able to significantly outperform conventional static offline network planning schemes in terms of throughput and satisfaction levels of small cells with regard to allocated bandwidths. Specifically, the throughput can be improved by 155 percent for the cloud radio scenario and 110.95 percent for the microwave backhaul scenario. The satisfaction level can be improved by 40 percent for interoperator spectrum sharing.\",\n \"Title: Outage Analysis of Cooperative Secrecy Multicast Transmission\\nYear: 2014\\n\\nAbstract: This work considers a multicast network in the presence of an eavesdropper. We investigate a cooperative multicast scheme which allows the users to function as relays. The secure outage behavior of this scheme is studied and the analytical expression of secure outage probability is derived. Numerical results show that the proposed cooperative multicast scheme outperforms the direct multicast without cooperation in terms of secure outage probability.\",\n \"Title: A Decentralized Sleep Mechanism in Heterogeneous Cellular Networks With QoS Constraints\\nYear: 2014\\n\\nAbstract: We introduce a sleep mechanism for energy efficiency in heterogeneous cellular networks, where macro base stations and small base stations coexist in the same frequency band. The strategy is to put high-power macro base stations into sleep mode and off-load the users to low-power small base stations or neighboring macro base stations. To do so, we first formulate a joint optimization problem to minimize the total energy consumption while maintaining the QoS of users. Then we decouple it into two subproblems: user association and resource allocation, and macro base station sleep mechanism. We propose a modified many-to-one matching algorithm to solve the first one and a voting-based dynamic sleep mechanism for the second one. Simulation results show that our scheme has both lower energy consumption and lower user blocking ratio compared with existing sleep mechanisms.\",\n \"Title: Partition function game for rate optimization in random interference networks\\nYear: 2012\\n\\nAbstract: Interference is one of the main limiting factors in wireless communication networks for system performance nowadays. In this paper, we study a coalitional game approach for rate optimization in a random interference networks where multiple transmission pairs transmit concurrently. We model the rate optimization problem as a partition function game. All transmission pairs form separated coalitions, and the pairs cooperate to transmit within each coalition. An iterative coalition structure generation algorithm is proposed to obtain partitions. This algorithm allows each transmission pair to make individual decision whether to stay in or depart from its current coalition. We prove that the proposed iterative algorithm can achieve a Nash-stable partition. In each coalition, we adopt the duality features of broadcast channel (BC) and multi-access channel (MAC) to maximize the sum-rate. Simulation results show that the proposed algorithm can improve the network performance significantly compared with location-based static partition forms.\",\n \"Title: Energy-efficient cross-layer design of delay-aware MIMO systems\\nYear: 2014\\n\\nAbstract: In this paper, we propose a cross-layer design model for multiple input and multiple output (MIMO) cellular systems, to solve the problem of energy efficient communications with delay demand. We first investigate the energy efficient multiple quadrature amplitude modulation (MQAM) constellation size for each transmission stream. With the demand of the packet delay, then we propose an adaptive MIMO/SIMO transmission mode by exploiting the intrinsic relationship between the upper layer packet delay and the constellation size, the symbol error rate (SER) from the physical layer. Simulations show that in order to maximize the energy efficiency and offer different Quality of Service (QoS) of delay simultaneously, a user should adaptively choose the constellation size as well as the transmission mode. In this framework, the tradeoff between energy efficiency and delay demand are well demonstrated.\",\n \"Title: Optimal training design and individual channel estimation for MIMO two-way relay systems in colored environment\\nYear: 2014\\n\\nAbstract: In this paper, while considering the impact of antenna correlation and the interference from neighboring users, we study the problem of channel estimation and training sequence design in multi-input multi-output (MIMO) two-way relaying (TWR) systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) and the broadcast (BC) phases. By deriving the optimal linear minimum mean-square-error estimators, the corresponding training design problems for the MAC and BC phases are formulated and solved. Subsequently, algorithms and, in some special cases, closed-form solutions for obtaining the optimal training sequences for channel estimation in TWR systems are derived. Moreover, to further reduce channel estimation overhead, the minimum required length of the training sequences are determined. Simulation results verify the effectiveness of the proposed training designs in improving channel estimation performance in TWR systems.\",\n \"Title: Channel estimation and carrier recovery in the presence of phase noise in OFDM relay systems\\nYear: 2014\\n\\nAbstract: In this paper, we analyze joint channel, carrier frequency offset (CFO), and phase noise estimation in orthogonal frequency division multiplexing (OFDM) relaying networks. To achieve this goal, a detailed transmission framework involving both training and data symbols is first presented. Next, a novel algorithm that applies the training symbols to jointly estimate the channel responses, CFO, and phase noise parameters based on the maximum a posteriori criterion is proposed. Additionally, to evaluate the performance of the proposed channel estimation and carrier recovery algorithms, we analyze the ambiguities among the estimated parameters. Based on this analysis, a new Hybrid Cramér-Rao Lower Bound (HCRLB) is derived, which can effectively avoid such ambiguities. The simulation results show that the proposed estimation algorithm can achieve a performance close to the derived HCRLB.\",\n \"Title: Optimal energy-efficient transmission for fading channels with an energy harvesting transmitter\\nYear: 2014\\n\\nAbstract: This paper investigates the optimal energy-efficient transmission policy of multi-channels in energy harvesting systems. We configure the transmitter with the active mode in which the energy cost includes the basic operation cost and transmission cost and signal processing cost, while with the sleep mode only counting the basic operation cost. Then the energy efficiency maximization problem of joint transmission time and power allocation is formulated and studied in the offline manner. Based on the fractional optimization theory, we transform the original fractional optimization problem into a series of subtractive-form optimization problems which are then further transformed into convex optimization problems. Then characteristics of the optimal solution are described based on the analysis of transmission time and power allocation. Finally, a special case without considering the basic operation cost as previous works assumed is studied. We find that the optimal policy results a best subchannel scheduling which can be viewed as the peaky transmission. Through this, the energy cost of the sleep mode in previous case can be interpreted as the switching operation cost.\",\n \"Title: Massive MIMO multicasting in noncooperative multicell networks\\nYear: 2014\\n\\nAbstract: We study the massive MIMO (multiple-input multiple-output) multicast transmission in multicell networks, where each base station (BS) is equipped with a large-scale antenna array and transmits a common message using a single beamformer to multiple mobile users. We first consider the case when each BS knows the perfect channel state information (CSI) of all its served users. We show that the asymptotically optimal beamformer structure at each BS is a linear combination of the channel vectors of its multicast users. The optimal combination coefficients are also obtained in closed form. Then we consider the imperfect CSI scenario where each BS obtains the CSI through uplink channel estimation. We propose a novel pilot scheme that estimates the compound channel rather than the individual channels of multicast users in each cell. This scheme is able to completely eliminate pilot contamination. The optimal power control of pilot transmission is also derived. Numerical results show that the performance of the proposed pilot scheme with pilot power control is close to that of the perfect CSI case.\",\n \"Title: Dynamic uplink/downlink configuration using Q-learning in femtocell networks\\nYear: 2014\\n\\nAbstract: With increasingly popular services containing asymmetric uplink (UL) and downlink (DL) traffic, Time-Division Duplexing (TDD) shows more advantages than Frequency-Division Duplexing (FDD) in wireless cellular networks due to its flexibility of dynamic UL/DL configuration. A major technical challenge in TDD is how to optimize the UL/DL switching point for each individual cell to meet its asymmetric traffic demand without causing severe cross-link interference. In this paper, we formulate the dynamic UL/DL configuration problem in non-cooperative femtocell networks as a multi-agent Q-learning process. Each femto base station (FBS) is treated as an agent. It senses its local interference environment and then takes an action. The optimal UL/DL switching policy is learned gradually by each FBS through trial and error with the objective of minimizing the overall packet transmission time. The proposed Q-learning based method takes both the asymmetric traffic demands and the interference into consideration. Simulation results show that our proposed method can achieve higher cell average packet throughput than the existing queue-aware dynamic TDD method and the fixed TDD method.\",\n \"Title: Power Control for MIMO Diversity Systems With Nonidentical Rayleigh Fading\\nYear: 2009\\n\\nAbstract: We investigate the performance limits and associated power-allocation problems in a multiple-antenna diversity system with statistical channel information available at the transmitter. The channels are assumed to be independent and nonidentically distributed Rayleigh fading. By studying both ergodic mutual information and information outage, we derive two simple and near-optimal power-allocation schemes. Specifically, for ergodic information rate maximization in a system with multiple transmit antennas and a single receive antenna, the proposed power control only depends on the ratios between channel gains and is independent of the total transmit signal-to-noise ratio (SNR). Meanwhile, for information outage minimization in a system with an arbitrary number of transmit and receive antennas, the proposed power allocation follows the water-filling principle and pours more power into the transmit antenna with a larger geometric mean of channel gains.\",\n \"Title: Channel Estimation, Carrier Recovery, and Data Detection in the Presence of Phase Noise in OFDM Relay Systems.\\nYear: 2016\\n\\nAbstract: Due to its time-varying nature, oscillator phase noise can significantly degrade the performance of the channel estimation, carrier recovery, and data detection blocks in high-speed wireless communication systems. In this paper, we propose a new data-aided joint channel, carrier frequency offset (CFO) and phase noise estimator for orthogonal frequency division multiplexing (OFDM) relay systems. Fo...\",\n \"Title: Joint Tx/Rx Energy-Efficient Scheduling in Multi-Radio Wireless Networks: A Divide-and-Conquer Approach.\\nYear: 2016\\n\\nAbstract: Most of the existing works on energy-efficient wireless communications only consider the transmitter (Tx) or the receiver (Rx) side power consumption, but not both. Moreover, the circuit power consumption is often assumed to be constant regardless of the transmission rate or the bandwidth. In this paper, we investigate the system-level energy-efficient transmission in multi-radio access networks b...\",\n \"Title: Energy-Efficient Resource Allocation for Wireless Powered Communication Networks.\\nYear: 2016\\n\\nAbstract: This paper considers a wireless powered communication network (WPCN), where multiple users harvest energy from a dedicated power station and then communicate with an information receiving station. Our goal is to investigate the maximum achievable energy efficiency (EE) of the network via joint time allocation and power control while taking into account the initial battery energy of each user. We f...\",\n \"Title: Caching Incentive Design In Wireless D2d Networks: A Stackelberg Game Approach\\nYear: 2016\\n\\nAbstract: Caching in wireless device-to-device (D2D) networks can be utilized to offload data traffic during peak times. However, the design of incentive mechanisms is challenging due to the heterogeneous preference and selfish nature of user terminals (UTs). In this paper, we propose an incentive mechanism in which the base station (BS) rewards those UTs that share contents with others using D2D communication. We study the cost minimization problem for the BS and the utility maximization problem for each UT. In particular, the BS determines the rewarding policy to minimize his total cost, while each UT aims to maximize his utility by choosing his caching policy. We formulate the conflict among UTs and the tension between the BS and the UTs as a Stackelberg game. We show the existence of the equilibrium and propose an iterative gradient algorithm (IGA) to obtain the Stackelberg Equilibrium. Extensive simulations are carried out to evaluate the performance of the proposed caching scheme and comparisons are drawn with several baseline caching schemes with no incentives. Numerical results show that the caching scheme under our incentive mechanism outperforms other schemes in terms of the BS serving cost and the utilities of the UTs.\",\n \"Title: Position-Based Compressed Channel Estimation and Pilot Design for High-Mobility OFDM Systems\\nYear: 2015\\n\\nAbstract: With the development of high-speed trains (HSTs) in many countries, providing broadband wireless services in HSTs is crucial. Orthogonal frequency-division multiplexing (OFDM) has been widely adopted for broadband wireless communications due to its high spectral efficiency. However, OFDM is sensitive to the time selectivity caused by high-mobility channels, which costs much spectrum or time resour...\",\n \"Title: Resource-Efficient Data Gathering in Sensor Networks for Environment Reconstruction.\\nYear: 2015\\n\\nAbstract: Environment reconstruction is to rebuild the physical environment in the cyberspace using the sensory data collected by sensor networks, which is a fundamental method for human to understand the physical world in depth. A lot of basic scientific work such as nature discovery and organic evolution heavily relies on the environment reconstruction. However, gathering large amount of environmental dat...\",\n \"Title: Generalized signal alignment for high mobility OFDM channels\\nYear: 2015\\n\\nAbstract: Generalized signal alignment (GSA) is recently proposed as a new transmission framework to achieve the maximum degrees of freedom in multi-user MIMO two-way relay channels. In this paper, we apply GSA in high mobility OFDM systems. To handle the inter-carrier interference (ICI) resulted from large Doppler frequency shift effectively, we propose subcarrier extension (SE)-GSA. Its idea is to treat each subcarrier as a virtual antenna and then apply GSA in the extended virtual MIMO channel. We take the MIMO two-way X relay channel as the system model. It well models to the scenario where a high speed train enters the edge of two adjacent cells and two mobile users inside the train are communicating with the base stations (BSs) through a relay station deployed on the train carriage. By jointly designing the compression matrix and precoding matrices in the virtual antenna domain, both inter-user interference and inter-carrier interference can be managed together. To reduce the computation complexity at the relay, a new method is proposed to design the precoding matrix at each source node. Simulation results demonstrate that the proposed SE-GSA achieves 25% and 66% higher throughput than the conventional signal alignment (SA) and time division duplex (TDD) transmission schemes, respectively, at high SNR with the train moving speed of 500 km/h.\",\n \"Title: Statistics-based channel estimation and ici mitigation in OFDM system over high mobility channel\\nYear: 2014\\n\\nAbstract: In this paper, we propose a statistics-based channel estimation and inter-carriers interference (ICI) mitigation scheme for the orthogonal frequency division multiplexing (OFDM) transmission over high speed railway communication. The proposed scheme offers a new channel estimation method based on compressed sensing by utilizing the sparsity of high speed train (HST) in the time domain channel. The wireless channel is expressed by a weighted time-domain channel interpolation. The interpolation weights are designed according to the channel statistics, and the position of the selected parameter of each path is designed based on coherence of the model structure. Furthermore, by utilizing the channel statistics, we develop the receive post-processing in the receiver for ICI mitigation. Numerical and simulation results verify the effectiveness of the proposed schemes.\",\n \"Title: Compressed channel estimation with joint pilot symbol and placement design for high mobility OFDM systems\\nYear: 2014\\n\\nAbstract: High mobility introduces significant Doppler frequency spread and hence imposes great challenge to channel estimation in orthogonal frequency division multiplexing (OFDM) systems. In this paper, we propose a new low coherence compressed channel estimation method for OFDM systems in the high mobility environment. Based on the compressed sensing (CS) coherence minimization criterion, we propose a new pilot design algorithm using the discrete stochastic optimization method to improve the estimation performance. The pilot symbol and pilot placement are jointly designed to obtain the optimal pilot. Numerical results demonstrate that the proposed method has a fast convergency property and achieves better MSE performance than existing channel estimation methods over high mobility channels.\",\n \"Title: Content-Centric Multicast Beamforming in Cache-Enabled Cloud Radio Access Networks.\\nYear: 2015\\n\\nAbstract: Multicast transmission and wireless caching are effective ways of reducing air and backhaul traffic load in wireless networks. This paper proposes to incorporate these two key ideas for content-centric transmission in a cloud radio access network (RAN) where multiple base stations (BSs) are connected to a central processor (CP) via finite-capacity backhaul links. Each BS has a cache with finite storage size and is equipped with multiple antennas. The BSs cooperatively transmit contents, either stored in the local cache or fetched from the CP, to multiple users in the network. Users requesting a same content form a multicast group and are served by a same cluster of BSs cooperatively using multicast beamforming. Assuming fixed cache placement, this paper investigates the joint design of multicast beamforming and content-centric BS clustering by formulating an optimization problem of minimizing the total network cost under the quality-of-service (QoS) constraints for each multicast group. The network cost involves both the transmission power and the backhaul cost. We model the backhaul cost using the mixed l(0)/l(2)-norm of beamforming vectors. To solve this non-convex problem, we first approximate it using the semidefinite relaxation (SDR) method and concave smooth functions. We then propose a difference of convex functions (DC) programming algorithm to obtain suboptimal solutions and show the connection of three smooth functions. Simulation results validate the advantage of multicasting and show the effects of different cache size and caching policies in cloud RAN.\",\n \"Title: User-Centric Base Station Clustering And Sparse Beamforming For Cache-Enabled Cloud Ran\\nYear: 2015\\n\\nAbstract: Cloud radio access network (Cloud RAN) is able to significantly improve the network capacity and energy efficiency through centralized processing of multiple distributed base stations (BSs). Yet it also places tremendous burden on backhaul links that connect these BSs. In this paper, we introduce a cache-enabled Cloud RAN, in which each BS is equipped with a local cache with limited storage capacity. If the content requested by a user is not cached at the serving BSs of the user, it will be distributed to the serving BSs via the backhaul links from the central processor (CP). We investigate the dynamic user-centric BS clustering and sparse beamforming by taking both channel condition and cache status into account. We formulate an optimization problem with the objective of minimizing the weighted sum of backhaul cost and transmit power cost subject to an individual signal-to-interference-and-noise ratio (SINR) constraint for each user. This problem is a mixed-integer non-linear programming (MINLP) problem. We apply the iterative reweighted l(1)-norm technique to find an approximate solution. Theoretical analysis also shows that all the BSs which cache the content requested by a user can always be included in the BS cluster of this user, regardless of their channel conditions. Based on this finding, we propose a cache-aware greedy selection BS clustering algorithm. Simulation results show that caching can greatly improve the tradeoff between backhaul capacity and transmit power. It is also demonstrated that popularity-aware caching is superior to random caching in Cloud RAN.\",\n \"Title: Optimal Degrees of Freedom Region for the Asymmetric MIMO Y Channel.\\nYear: 2016\\n\\nAbstract: This letter studies the optimal degrees of freedom (DoF) region for the asymmetric three-user MIMO Y channel with antenna configuration (M 1 , M 2 , M 3 , N), where Mi is the number of antennas at user i and N is the number of antennas at the relay node. The converse is proved by using the cutset theorem and the genie-message approach. To prove the achievability, we divide the DoF tuples in the outer bound into two cases. For each case, we show that the DoF tuples are achievable by collectively utilizing antenna deactivation, pairwise signal alignment, and cyclic signal alignment techniques. This letter not only offers a complete characterization of DoF region for the considered channel model, but also provides a new and elegant achievability proof.\",\n \"Title: Fundamental Tradeoff between Storage and Latency in Cache-Aided Wireless Interference Networks.\\nYear: 2017\\n\\nAbstract: This paper studies the fundamental tradeoff between storage and latency in a general wireless interference network with caches equipped at all transmitters and receivers. The tradeoff is characterized by an information-theoretic metric, normalized delivery time (NDT), which is the worst case delivery time of the actual traffic load at a transmission rate specified by degrees of freedom of a given ...\",\n \"Title: Communications, caching, and computing for content-centric mobile networks: part 1 [guest editorial].\\nYear: 2016\\n\\nAbstract: The driving forces behind the exponential growth in mobile cellular network traffic have fundamentally shifted from the steady increase in demand for conventional \\\\\\\"connection-centric\\\\\\\" communications, such as phone calls and text messages, to the explosion of \\\\\\\"content- centric\\\\\\\" communications, such as video streaming and content sharing. The Cisco Visual Networking Index projects that video traffic will amount to 72 percent of global mobile data traffic by 2019. The mobile cellular network architectures of today are, however, still designed with a connection-centric communication mindset. Moreover, the myriad technological advances proposed for beyond fourth generation (4G) and 5G mobile networks still mostly focus on capacity increase, which is fundamentally constrained by the limited radio spectrum resources as well as the diminishing investment efficiency for operators, and therefore will always lag behind the growth rate of mobile traffic. It can be argued that the logjam in cellular networks cannot be addressed by improving connection capability alone, but instead must be tackled by fundamentally addressing the underlying ineffectiveness of the current communication architecture for massive content delivery.\",\n \"Title: Compressed Channel Estimation With Position-Based ICI Elimination for High-Mobility SIMO-OFDM Systems.\\nYear: 2016\\n\\nAbstract: Orthogonal frequency-division multiplexing (OFDM) is widely adopted for providing reliable and high-data-rate communication in high-speed train (HST) systems. However, with increasing train mobility, the resulting large Doppler shift introduces intercarrier interference (ICI) in OFDM systems and greatly degrades channel estimation accuracy. Therefore, it is necessary and important to investigate r...\",\n \"Title: Linear Precoding For Cognitive Multiple Access Wiretap Channel With Finite-Alphabet Inputs\\nYear: 2016\\n\\nAbstract: This paper investigates the linear precoder design for cognitive multiple-access wiretap channel (CMAC-WT), where two secondary-user transmitters (STs) communicate with one secondary-user receiver (SR) in the presence of an eavesdropper and subject to interference threshold constraints at primaryuser receivers (PRs). It designs linear precoders to maximize the ergodic secrecy sum rate for multiple-input multiple-output (MIMO) CMAC-WT under finite-alphabet inputs and statistical channel state information (CSI). For this non-convex problem, a two-layer algorithm is proposed by embedding the convex-concave procedure into an outer approximation framework. The key idea of this algorithm is to reformulate the approximated ergodic secrecy sum rate as a difference of convex (DC) functions, and then generate a sequence of simpler relaxed sets to approach the non-convex feasible set. In this way, near optimal precoding matrices are obtained by maximizing the approximated ergodic secrecy sum rate over a sequence of relaxed sets. Numerical results show that the proposed precoder design provides a significant performance gain over the Gaussian precoding method in the medium and high SNR regimes.\",\n \"Title: On The Sum Dof Of The Asymmetric Four-User Mimo Y Channel\\nYear: 2016\\n\\nAbstract: This work studies the sum degrees of freedom (DoF) of the asymmetric four-user MIMO Y channel, where each user i, for 1 <= i <= 4, is equipped with Mi antennas, and the relay is equipped with N antennas. By using the genie message approach, we derive that the sum DoF is upper bounded by min {Sigma(4)(i= 1) Mi(,) 2 Sigma(4)(i= 2) M-i, 2N, 2/7 Sigma(for all i for all j> i) max{N, M-i + M-j}, where M-1 >= M-2 >= M-3 >= M-4. Then, we show that the bound is tight under certain antenna constraints using signal alignment, generalized signal alignment, and antenna deactivation techniques.\",\n \"Title: Embracing big data with compressive sensing: a green approach in industrial wireless networks.\\nYear: 2016\\n\\nAbstract: New-generation industries heavily rely on big data to improve their efficiency. Such big data are commonly collected by smart nodes and transmitted to the cloud via wireless. Due to the limited size of smart node, the shortage of energy is always a critical issue, and the wireless data transmission is extremely a big power consumer. Aiming to reduce the energy consumption in wireless, this article introduces a potential breach from data redundancy. If redundant data are no longer collected, a large amount of wireless transmissions can be cancelled and their energy saved. Motivated by this breach, this article proposes a compressive-sensing-based collection framework to minimize the amount of collection while guaranteeing data quality. This framework is verified by experiments and extensive realtrace- driven simulations.\",\n \"Title: Fundamental Storage-Latency Tradeoff in Cache-Aided MIMO Interference Networks.\\nYear: 2017\\n\\nAbstract: Caching is an effective technique to improve user perceived experience for content delivery in wireless networks. Wireless caching differs from traditional web caching in that it can exploit the broadcast nature of wireless medium and hence, opportunistically change the network topologies. This paper studies a cache-aided MIMO interference network with three transmitters each equipped with M anten...\",\n \"Title: A New Polar Coding Scheme for the Interference Channel.\\nYear: 2016\\n\\nAbstract: We consider the problem of polar coding for the 2-user discrete memoryless interference channel (DM-IC) to achieve the Han-Kobayashi region, the best achievable rate region to date. Existing schemes are designed according to the original description of the Han-Kobayashi region, in which two deterministic functions that map auxiliary random variables to channel inputs are assumed to be known. Inspired by Chong et al.u0027s compact description of the Han-Kobayashi region, which uses joint distributions of random variables instead of deterministic functions, we find that the Han-Kobayashi region can be achieved in a simpler way. The original Han-Kobayashi strategy requires joint decoding of the intended senderu0027s private message and both sendersu0027 common messages at each receiver. In this paper, we show that all corner points of the Han-Kobayashi region can be achieved using partially joint decoders, i.e., each receiver only needs to jointly decode two of the three messages, either both sendersu0027 common messages, or the unintended senderu0027s common message and the intended senderu0027s private message. Based on this finding and enlightened by Goela et al.u0027s superposition polar coding schemes for the broadcast channels, we design two types of polar coding schemes, which can be seen as extensions of Carleialu0027s superposition coding scheme for the DM-IC with more powerful joint decoders, and show that every corner point can be achieved using one of the proposed schemes. The joint decoders and the corresponding code constructions are implemented using the 2-user multiple access channel (MAC) polarization technique based on Arikanu0027s monotone chain rule expansions, which has similar complexity to the single-user case. The chaining method which has already been widely used for constructing universal polar codes is adopted to solve the problem of alignment of polar indices.\",\n \"Title: Optimization and Analysis of Probabilistic Caching in $N$-tier Heterogeneous Networks.\\nYear: 2018\\n\\nAbstract: In this paper, we study the probabilistic caching for an N-tier wireless heterogeneous network (HetNet) using stochastic geometry. A general and tractable expression of the successful delivery probability (SDP) is first derived. We then optimize the caching probabilities for maximizing the SDP in the high signal-to-noise ratio regime. The problem is proved to be convex and solved efficiently. We n...\",\n \"Title: Polar Coding for Block Fading Channels.\\nYear: 2017\\n\\nAbstract: In this paper, we consider the problem of polar coding for block fading channels, with emphasis on those with instantaneous channel state information (CSI) at neither the transmitter nor the receiver. Our approach is to decompose a block fading channel of $T_c$ symbols per coherent interval into $T_c$ binary-input sub-channels in a capacity-preserving way, and design a polar code for each of them. For the case when instantaneous CSI is available at the receiver, a random interleaver can be used to enable joint encoding and decoding of all sub-channels so as to enhance the finite length performance. It is shown that our proposed schemes achieve the ergodic capacity of binary-input block fading channels under various CSI assumptions.\",\n \"Title: Secure Polar Coding for the Two-Way Wiretap Channel.\\nYear: 2018\\n\\nAbstract: In this paper, we consider the problem of polar coding for secure communications over the two-way wiretap channel, where two legitimate users communicate with each other simultaneously, while a passive eavesdropper overhears a combination of their exchanged signals. We design a low complexity polar coded cooperative jamming scheme that achieves the whole secrecy rate region of the general two-way wiretap channel under the strong secrecy criterion. The chaining method is used to make proper alignment of polar indices. The randomness required to be shared between two legitimate users is treated as a limited resource and we show that its rate can be made negligible by increasing the blocklength and the number of chained blocks. For the special case when the eavesdropper channel is degraded with respect to the legitimate ones, a simplified scheme is proposed which can simultaneously ensure reliability and weak secrecy within a single transmission block.\",\n \"Title: Channel Measurement And Performance Of Multicast Beamforming In Campus Network\\nYear: 2016\\n\\nAbstract: Multicast plays an important role in wireless networks to delivery a common message to multiple users simultaneously. Multicast beamforming can further boost the system performance by utilizing channel state information (CSI) at the base station (BS) equipped with multiple antennas. This paper provides a validation of multicast beamforming over actual channels measured in the Shanghai Jiao Tong University (SITU) campus wireless network, a FDD LTE network. We first build a receiver prototype using USRP N210 and LabV1EW for channel measurement. A single base station with 4 antennas and 3 single antenna receivers are considered. Based on the measured actual CSI, we then evaluate the performance of nmIticast beamforming under the quality of service (QoS) problem formulation, which is to minimize the transmit power consumption subject to an individual Signal to Noise Ratio (SNR) constraint for each user receiver. The Semi-Delinite Relaxation (SDR) approach is adopted to find an solution close to primitive solution. Experimental results demonstrate that multicast transmission using a single beamformer provides significant power gain over unicast transmission with multiple beamformers under the same QoS constraints in our considered campus network.\",\n \"Title: A Storage-Latency Tradeoff Study for Cache-Aided MIMO Interference Networks.\\nYear: 2016\\n\\nAbstract: Caching is an effective technique to improve user perceived experience for massive content delivery in wireless networks. An essential problem in cache-aided wireless networks is to find what and how much gain can be achieved by caching. This paper provides a study of the fundamental storage-latency tradeoff for a cache-aided MIMO interference network with 3 transmitters and 3 receivers and each node equipped with.. antennas. By using a newly proposed novel file splitting and caching strategy, the network topology during the content delivery phase is turned opportunistically to MIMO X channel, MIMO broadcast channel, MIMO multicast channel, or a hybrid form of these channels. Linear-precoding based interference management schemes such as interference alignment and neutralization over finite symbol extension are designed for these channels. We characterize the storage-latency tradeoff by fractional delivery time (FDT), a metric to evaluate the worst-case delivery time of the actual traffic load at a rate specified by the degrees of freedom (DoF) of the considered channel. The achievable FDT of our proposed scheme decreases piecewise linearly with the normalized cache sizes and is inversely proportional to the number of antennas. It is also shown that the achievable FDT is optimal at certain cache size regions and is within a multiplicative gap of 2 from the optimum at other regions.\",\n \"Title: Linear Precoding for Fading Cognitive Multiple-Access Wiretap Channel With Finite-Alphabet Inputs\\nYear: 2017\\n\\nAbstract: We investigate the fading cognitive multiple-access wiretap channel (CMAC-WT), in which two secondary-user transmitters (STs) send secure messages to a secondary-user receiver (SR) in the presence of an eavesdropper and subject to interference threshold constraints at multiple primary-user receivers (PRs). We design linear precoders to maximize the average secrecy sum rate for a multiple-input-mul...\",\n \"Title: Modeling, Analysis, and Optimization of Coded Caching in Small-Cell Networks.\\nYear: 2017\\n\\nAbstract: Coded caching is able to exploit accumulated cache size and hence superior to uncoded caching by distributing different fractions of a file in different nodes. This paper investigates coded caching in a large-scale small-cell network (SCN) where the locations of small base stations (SBSs) are modeled by stochastic geometry. We first propose a content delivery framework, where multiple SBSs that ca...\",\n \"Title: Autonomous Relay for Millimeter-Wave Wireless Communications.\\nYear: 2017\\n\\nAbstract: Millimeter-wave (mmWave) communication is the rising technology for next-generation wireless transmission. Benefited by its abundant bandwidth and short wavelength, mmWave is advanced in multi-gigabit transmittability and beamforming. In contrast, the short wavelength also makes mmWave easily blocked by obstacles. In order to bypass these obstacles, relays are widely needed in mmWave communications. Unmanned autonomous vehicles (UAVs), such as drones and self-driving robots, enable the mobile relays in real applications. Nevertheless, it is challenging for a UAV to find its optimal relay location automatically. On the one hand, it is difficult to find the location accurately due to the complex and dynamic wireless environment; on the other hand, most applications require the relay to forward data immediately, so the autonomous process should be fast. To tackle this challenge, we propose a novel method AutoRelay specialized for mmWave communications. In AutoRelay, the UAV samples the link qualities of mmWave beams while moving. Based on the real-time sampling, the UAV gradually adjusts its path to approach the optimal location by leveraging compressive sensing theory to estimate the link qualities in candidate space, which increases the accuracy and save the time. Performance results demonstrate that AutoRelay outperforms existing methods in achieving an accurate and efficient relay strategy.\",\n \"Title: Low-Complexity Hybrid Analog/Digital Beamforming For Multicast Transmission In Mmwave Systems\\nYear: 2017\\n\\nAbstract: This paper studies multi-group multicast beamforming with a hybrid large-scale antenna array in millimeter wave (mmWave) communication systems. A low-complexity hybrid structure is adopted, where each RF chain is only connected to part of the antenna elements. We formulate a hybrid analog and digital beamforming design problem for multi-group multicast transmission with the objective of minimizing the total transmit power at the base station, subject to an individual signal-to-interference-plus-noise ratio constraint for each multicast group. The problem is very challenging and its global optimal solution is difficult to obtain. We first adopt alternating minimization method to design the analog and digital beamformer alternatively. Then we solve each of the analog and digital subproblems through solving a sequence of convex problems via concave-convex procedure (CCP). Each convex CCP subproblem is reformulated as a novel alternating direction method of multipliers (ADMM) form. Our ADMM reformulation enables that each updating step can be decomposed into multiple subproblems with much smaller size, which can be solved optimally in parallel with closed-form expressions. Simulation results show that our algorithm can achieve favorable performance with very low complexity compared with the state-of-art methods.\",\n \"Title: Stochastic Modeling, Analysis And Optimization Of Coded Caching In Small-Cell Networks\\nYear: 2017\\n\\nAbstract: Coded caching is able to exploit accumulated cache size in a wireless network by storing fractions of files in each node. In this work, we model, analyze, and optimize coded caching in cache-enabled small-cell networks (SCNs). We first propose a content delivery framework for coded caching, where multiple small base stations (SBSs) that cache different coded packets of a desired file transmit simultaneously upon a user request and the packets are decoded using successive interference cancellation (SIC)-based receiver. A closed-form expression for the successful transmission probability with SIC receiver in the high signal-to-noise ratio (SNR) region is derived by using stochastic geometry. We next optimize the cache placement to maximize the average fraction of offloaded traffic by the cache-enabled SBSs. The coded cache placement problem is formulated as a multiple-choice knapsack problem (MCKP). By exploiting the analytic properties of the average traffic offload fraction, we propose a greedy but optimal algorithm. Numerical results show our proposed coded caching scheme facilitated by simultaneous transmission and SIC-based receiving significantly outperforms uncoded caching. In addition, the coded caching only needs to split each file into a small number of fragments to approach an ideal performance.\",\n \"Title: Cooperative caching for spectrum access in cognitive radio networks\\nYear: 2017\\n\\nAbstract: In this paper, we investigate cooperative caching for spectrum access in cognitive radio networks. By cooperative caching, we mean that the unlicensed secondary base station (SBS) can cache certain primary contents to serve primary users, in exchange for the opportunities to access the licensed spectrum. We consider the joint optimization of caching and scheduling of the SBS to maximize the weighted average number of satisfied secondary requests under the average available time constraint and the cache capacity constraint. This problem is a mixed-integer bilinear programming, which is challenging in general. By exploring the special structure of the problem, we first show that the optimal caching satisfies a cache-split structure and the optimal scheduling satisfies a rate-ratio structure. Then, based on these optimality properties, we transform the original problem into a simplified joint cache splitting and SU partitioning optimization problem, and propose an efficient algorithm to solve it optimally. Moreover, we investigate the impacts of the primary and secondary content popularity distributions on the system performance. Numerical results verify the theoretical analysis and provide some counter-intuitive insights.\",\n \"Title: Design of Contract-Based Trading Mechanism for a Small-Cell Caching System.\\nYear: 2017\\n\\nAbstract: Recently, content-aware-enabled distributed caching relying on local small-cell base stations (SBSs), namely, smallcell caching, has been intensively studied for reducing transmission latency as well as alleviating the traffic load over backhaul channels. In this paper, we consider a commercialized small-cell caching system consisting of a network service provider (NSP), several content providers ...\",\n \"Title: Analysis and Optimization of Probabilistic Caching in Multi-Antenna Small-Cell Networks.\\nYear: 2017\\n\\nAbstract: Previous works on cache-enabled small-cell networks (SCNs) with probabilistic caching often assume that each user is connected to the nearest small base station (SBS) among all that have cached its desired content. The user may, however, suffer strong interference from other SBSs which do not cache the desired content but are geographically closer. In this work, we investigate this issue by deploying multiple antennas at each SBS. We first propose a user-centric SBS clustering model where each user chooses its serving SBS only from a cluster of.. nearest SBSs with.. being a fixed cluster size. Two beamforming schemes are considered. One is coordinated beamforming, where each SBS uses zero-forcing (ZF) beamformer to null out the interference within the coordination cluster. The other is uncoordinated beamforming, where each SBS simply applies matched-filter (MF) beamformer. Using tools from stochastic geometry, we obtain tractable expressions for the successful transmission probability (STP) of a typical user for both cases in the high signal-tonoise ratio (SNR) region. Tight approximations in closed-form expressions are also obtained. We then formulate and solve the optimal probabilistic caching problem to maximize the STP. Numerical results reveal interesting insights on the choices of ZF and MF beamforming in multi-antenna cache-enabled SCNs.\",\n \"Title: Content Delivery in MIMO Broadcast Channels with Decentralized Coded Caching.\\nYear: 2017\\n\\nAbstract: Caching at the wireless edge is an effective way to trade the scarce communication bandwidth with the more sustainable storage size through traffic time shifting. Multiple-input multiple-output (MIMO), on the other hand, can bring spatial multiplexing gain in wireless channels. This work is to investigate the combined effect of MIMO and caching in a three-user cache-aided MIMO broadcast channel, where the base station is equipped with.. antennas and each user is equipped with.. antennas. Decentralized coded caching is adopted in this paper, which converts the content delivery phase to a transmission problem in a broadcast channel with general message sets. We first derive an achievable degrees of freedom (DoF) region of the three-user MIMO broadcast channel with general message sets. Based on this region, we then obtain an achievable normalized delivery time (NDT), which illustrates the spatial multiplexing gain of MIMO through simultaneous transmission of multiple multicast messages intended to different user sets. It is shown that the achievable NDT is optimal at certain cases and is within a multiplicative gap of 3 from the optimum at other cases.\",\n \"Title: Backhaul-Constrained Joint Beamforming for Non-Orthogonal Multicast and Unicast Transmission.\\nYear: 2017\\n\\nAbstract: The demand for providing multicast services in emerging cellular networks is increasing. This paper proposes a non-orthogonal transmission framework based on layered-division multiplexing (LDM) to incorporate multicast and unicast services into cellular networks with limited-capacity backhaul. We adopt a two-layer LDM structure where the first layer is intended for multicast services, the second layer is for unicast services, and the two layers are superposed with different beamformers and decoded by each user receiver using successive interference cancellation. To optimize the non-orthogonal transmission, we formulate a joint multicast and unicast beamforming design problem with adaptive base station (BS) clustering that aims to maximize the weighted sum of multicast rate and unicast rate under peak power constraints and peak backhaul constraints on each BS. The problem is a sparse optimization problem and NP-hard. By means of smoothed l(0)-norm approximation and novel algebraic operations, we transform it into a difference of convex (DC) programming, which is solved using convex-concave procedure (CCP) with guaranteed convergence. Simulation results demonstrate the superiority of the proposed algorithm, especially when the backhaul constraint is not too stringent. Results also show that the proposed LDM-based non-orthogonal scheme can achieve a much larger multicast-unicast rate region than orthogonal schemes.\",\n \"Title: On the DoF Region for the Asymmetric MIMO Two-Way X Relay Channel.\\nYear: 2018\\n\\nAbstract: In this paper, we study the degrees of freedom (DoF) region for the multiple-input multiple-output two-way X relay channel with asymmetric antenna setting. In this channel model, there are two groups of source nodes, each group contains two source nodes, every source node in one group exchanges independent messages with every source node in another group via a common relay node, and each node has ...\",\n \"Title: Joint Base Station Clustering and Beamforming for Non-Orthogonal Multicast and Unicast Transmission with Backhaul Constraints.\\nYear: 2018\\n\\nAbstract: The demand for providing multicast services in cellular networks is continuously and fastly increasing. In this paper, we propose a non-orthogonal transmission framework based on layered-division multiplexing (LDM) to support multicast and unicast services concurrently in cooperative multi-cell cellular networks with a limited backhaul capacity. We adopt a two-layer LDM structure where the first l...\",\n \"Title: Robust design of hybrid multicast beamforming with phase error in mmWave systems\\nYear: 2017\\n\\nAbstract: This paper studies the robust beamforming design for multi-group multicast transmission with a hybrid analog and digital structure in millimeter wave (mmWave) communication systems. Unlike the conventional additive error model, we consider a novel multiplicative phase error model which is more suitable for capturing the channel uncertainty in mmWave systems. We adopt a partially-connected hybrid structure where each radio frequency (RF) chain is connected to an exclusive subset of antenna elements at the base station. The robust design problem is formulated to minimize the total transmit power while satisfying the outage constraint for each user's signal-to-interference-plus-noise ratio (SINR). We first utilize the alternating minimization method to optimize the analog and digital beamformers alternatively. Each of these two subproblems is then solved approximately by using the second-order Taylor expansion together with the Bernstein-type inequality. Simulation results show that the approximation is quite safe and the outage constraint can be well satisfied. It is also shown that the power performance of the proposed robust design is within 1dB close to the ideal case when the standard derivation of the channel phase error is within 5.7°.\",\n \"Title: Communications, Caching and Computing for Mobile Virtual Reality: Modeling and Tradeoff.\\nYear: 2018\\n\\nAbstract: Virtual reality (VR) over wireless is emerging as an important use case of 5G networks. Fully-immersive VR experience requires the wireless delivery of huge data at ultra-low latency, thus leading to ultra-high transmission rate requirement for wireless communications. This challenge can be largely addressed by the recent network architecture known as mobile edge computing (MEC) network, which enables caching and computing capabilities at the edge of wireless networks. This paper presents a novel MEC-based mobile VR delivery framework that is able to cache parts of the field of views (FOVs) in advance and compute certain post-processing procedures on demand at the mobile VR device. To minimize the average required transmission rate, we formulate the joint caching and computing optimization problem to determine which FOVs to cache, whether to cache them in 2D or 3D as well as which FOVs to compute at the mobile device under cache size, average power consumption as well as latency constraints. When FOVs are homogeneous, we obtain a closed-form expression for the optimal joint policy which reveals interesting communications-caching-computing tradeoffs. When FOVs are heterogeneous, we obtain a local optima of the problem by transforming it into a linearly constrained indefinite quadratic problem and then applying concave convex procedure. Numerical results demonstrate the proposed mobile VR delivery framework can significantly reduce communication bandwidth while meeting low latency requirement.\",\n \"Title: Fitness-Aware Coded Multicasting for Decentralized Caching With Finite File Packetization.\\nYear: 2018\\n\\nAbstract: Coded caching has been shown to significantly reduce traffic load for wireless content delivery by creating coded multicasting opportunities. However, its order-optimal memory-load tradeoff performance requires the file size to go to infinity or grow exponentially with the number of users. This letter introduces a new delivery scheme for decentralized cache placement in practical settings with fin...\",\n \"Title: User-Centric Joint Access-Backhaul Design for Full-Duplex Self-Backhauled Wireless Networks.\\nYear: 2018\\n\\nAbstract: Full-duplex self-backhauling is promising to provide cost-effective and flexible backhaul connectivity for ultra-dense wireless networks, but also poses a great challenge to resource management between the access and backhaul links. In this paper, we propose a user-centric joint access-backhaul transmission framework for full-duplex self-backhauled wireless networks. In the access link, user-centric clustering is adopted so that each user is cooperatively served by multiple small base stations (SBSs). In the backhaul link, user-centric multicast transmission is proposed so that each user’s message is treated as a common message and multicast to its serving SBS cluster. We first formulate an optimization problem to maximize the network weighted sum rate through joint access-backhaul beamforming and SBS clustering when global channel state information (CSI) is available. This problem is efficiently solved via the successive lower-bound maximization approach with a novel approximate objective function and the iterative link removal technique. We then extend the study to the stochastic joint access-backhaul beamforming optimization with partial CSI. Simulation results demonstrate the effectiveness of the proposed algorithms for both full CSI and partial CSI scenarios. They also show that the transmission design with partial CSI can greatly reduce the CSI overhead with little performance degradation.\",\n \"Title: User-Centric Joint Access-Backhaul Design for Full-Duplex Self-Backhauled Cooperative Networks.\\nYear: 2018\\n\\nAbstract: In-band full-duplex (IBFD) self-backhauling is promising to provide cost-effective and flexible backhaul connectivity in ultra-dense wireless networks. In this paper, we propose a user-centric joint access-backhaul transmission framework for performance optimization in IBFD-enabled self-backhauled cooperative wireless networks. In the access link, user-centric clustering is adopted so that each user is cooperatively served by a cluster of small base stations (SBSs) via joint beamforming. In the backhaul link, user-centric multicast transmission is proposed so that the macro base station (MBS) treats each user's data as a multicast message and sends it to its serving SBS cluster. We formulate an optimization problem to maximize the endto-end weighted sum rate of all users under power constraints through joint design of multicast beamforming in the backhaul link as well as SBS clustering and beamforming in the access link. We first tackle the joint access-backhaul beamforming problem under given SBS clustering by transforming it into a manifold optimization problem, for which a stationary solution is obtained using the Riemannian optimization technique. We then develop a heuristic algorithm to determine the SBS clustering. Simulation results demonstrate the effectiveness of the proposed algorithms.\",\n \"Title: Exploiting Computation Replication in Multi-User Multi-Server Mobile Edge Computing Networks.\\nYear: 2018\\n\\nAbstract: In mobile edge computing (MEC) systems, mobile devices can offload their computation-intensive tasks to edge servers to save energy and shorten latency. However, the extra latency for downloading the computed results back may degrade the benefits of computation offloading if the downlink channel suffers severe fading and interference. In this work, we exploit computation replication in task offloading to reduce the download latency in multi-user multi-server MEC networks. The main idea is to partition the task generated by each user into multiple subtasks, and offload each subtask to a set of MEC servers via the uplink channel for repeated execution. The duplication of computation results on multiple servers thus enables data-sharing based transmission cooperation to send the results back to users. Next, we adopt an asymptotic total latency that accounts the uploading, computing and results downloading phases as the performance metric to capture the tradeoff between the increased computation load and the reduced communication time. We formulate a linear programming problem to optimize the task partition ratios for minimizing the total latency. We show that there exists an optimal degrees of replication (the number of MEC servers to compute the same subtask) and an associated task partition strategy for optimal latency performance. Our finding reveals great advantage of computation replication for latency reduction in multi-server MEC networks where the output data size of each computation task is non-negligible.\",\n \"Title: Modeling and Trade-off for Mobile Communication, Computing and Caching Networks.\\nYear: 2018\\n\\nAbstract: This paper considers a new mobile edge computing (MEC) model where the MEC server has the input and output data of all computation tasks and communicates with multiple caching-and-computing-enabled mobile devices via a shared wireless link. Each mobile device can pre-store the input or output data of a task and also execute a task locally. We aim to investigate the impact of local caching and computing at mobile devices as well as content-centric multicast transmission on the saving of required bandwidth on the wireless link. To this end, we first formulate a joint caching and computing decision optimization problem to minimize the required transmission bandwidth subject to latency, caching and energy constraints at each mobile device in the general case. The joint policy optimization problem is shown to be NP-hard. Based on equivalent transformation and exact penalization of the problem, a stationary point is obtained via concave convex procedure. In the special case where all the computation tasks are symmetric and user requests are uniform, we obtain the closed-form expressions for the local caching gain, local computing gain, and multicasting gain. Our results indicate that exploiting the computing and caching resources at mobile devices can provide significant bandwidth savings.\",\n \"Title: Collaborative Multi-Agent Reinforcement Learning of Caching Optimization in Small-Cell Networks.\\nYear: 2018\\n\\nAbstract: Previous works on learning-based caching problems often only focus on a single base station (BS) scenario. For works considering multiple BSs, the coordination among BSs only exists in the cache placement phase after the learning phase that each BS estimates the file popularity independently. In this work, we investigate the cache strategy design problem in small cell networks (SCNs) with multiple small base stations (SBSs) when user preferences are unknown. We model this multi-agent decision making problem in a multi-armed bandit (MAB) perspective. We first tackle this problem with the centralized MAB algorithm and distributed multi-agent MAB (MAMAB) algorithm. For the centralized algorithm, it considers the coordinations among SBSs but the computational complexity grows exponentially with the number of SBSs. For the distributed one, the computational complexity grows linearly with the number of SBSs but the coordinations among SBSs are totally ignored. To take both coordination among SBSs and computational complexity into account, we propose a collaborative MAMAB algorithm to learn the cache strategy directly, rather than learning the user preferences. The simulation results show that the collaborative MAMAB approaches the performance of the greedy algorithm when the user preferences are perfectly known.\",\n \"Title: A Channel Sensing Based Design For Lte In Unlicensed Bands\\nYear: 2015\\n\\nAbstract: With the exponential growth of wireless data traffic and the increasing scarcity of licensed spectrum, mobile network operators intend to use the unlicensed spectrum, such as the Industrial, Scientific and Medical (ISM) bands and TV white space, to offload their traffic. In the future, it is very likely that two of the most prominent wireless technologies, Long Term Evolution (LTE) and WiFi, will coexist on the same unlicensed bands. Existing simulation results show that LTE is slightly impacted by such coexistence while WiFi is severely hampered by LTE transmissions. In order to realize a harmonious LTE/WiFi coexistence, we propose two channel sensing schemes for LTE in unlicensed bands, i.e., periodic sensing and persistent sensing. Simulation results show that the proposed channel sensing schemes can provide a reasonable tradeoff between LTE and WiFi when they coexist with each other.\",\n \"Title: ADMM-Based Fast Algorithm for Multi-Group Multicast Beamforming in Large-Scale Wireless Systems.\\nYear: 2017\\n\\nAbstract: Multi-group multicast beamforming in wireless systems with large antenna arrays and massive audience is investigated in this paper. Multicast beamforming design is a well-known non-convex quadratically constrained quadratic programming (QCQP) problem. A conventional method to tackle this problem is to approximate it as a semi-definite programming problem via semi-definite relaxation, whose perform...\",\n \"Title: Multicast Beamforming Design in Multicell Networks With Successive Group Decoding.\\nYear: 2017\\n\\nAbstract: We consider a generic problem of multicast beamforming design in multicell networks where each base station (BS) has multiple independent messages to multicast and each user intends to decode an arbitrary subset of messages sent from all BSs using successive group decoding (SGD). We first formulate the total transmit power minimization problem subject to the constraints that a target rate vector i...\",\n \"Title: Cache-Aided Interference Management in Partially Connected Wireless Networks.\\nYear: 2017\\n\\nAbstract: Cache-aided communication is emerging as a new topic in wireless networks. Previous works have shown that caching in interference networks can change the interference topology by changing the information flow and hence facilitate advanced interference management. This paper studies the gain of caching in partially connected interference networks where each receiver can only communicate with a subset of transmitters. The performance is characterized by an information-theoretic metric, normalized delivery time (NDT). We obtain an order-optimal NDT for the (K + L - 1) x K partially connected linear interference network with any number of receivers K, any receiver connectivity L <= K, and with caches equipped at all transmitters and receivers. The cache placement phase adopts a file splitting strategy tailor-made for the partial receiver connectivity. Via the aid of virtual receivers, the proposed delivery strategy exploits coded multicasting gain by XOR combining and transmitter coordination gain by interference alignment. In the special case when L is a divisor of K, our NDT results are directly applicable to K x K partially connected circular interference networks.\",\n \"Title: Polar Coding Strategies for the Interference Channel With Partial-Joint Decoding\\nYear: 2019\\n\\nAbstract: Existing polar coding schemes for the two-user interference channel follow the original idea of Han and Kobayashi, in which component messages are encoded independently and then mapped by some deterministic functions (i.e., homogeneous superposition coding). In this paper, we propose a new polar coding scheme for the interference channel based on the heterogeneous superposition coding approach of Chong, Motani, and Garg. We prove that fully joint decoding (the receivers simultaneously decode both senders’ common messages and the intended sender’s private message) in the Han–Kobayashi strategy can be simplified to two types of partial-joint decoding, which are friendly to polar coding with practical decoding algorithms. The proposed coding scheme requires less auxiliary random variables and no deterministic functions and can be efficiently constructed. Furthermore, we extend this result to interference networks and show that partial-joint decoding is a general method for designing heterogeneous superposition polar coding schemes in interference networks.\",\n \"Title: Fundamental Limits Of Decentralized Caching In Fog-Rans With Wireless Fronthaul\\nYear: 2018\\n\\nAbstract: This paper aims to characterize the synergy of distributed caching and wireless fronthaul in a fog radio access network (Fog- RAN) where all edge nodes (ENs) and user equipments (UEs) have a local cache and store contents independently at random. The network operates in two phases, a file-splitting based decentralized cache placement phase and a fronthaul-aided content delivery phase. We adopt normalized delivery time (NDT) to characterize the asymptotic latency performance with respect to cache size and fronthaul capacity. Both an achievable upper bound and a theoretical lower bound of NDT are obtained, and their multiplicative gap is within 12. In the proposed delivery scheme, we utilize the fronthaul link, by exploiting coded multicasting, to fetch both non-cached and cached contents to boost EN cooperation in the access link. In particular, to fetch contents already cached at ENs, an additional layer of coded multicasting is added on the coded messages desired by UEs in the fronthaul link. Our analysis shows that the proposed delivery scheme can balance the delivery latency between the fronthaul link and access link, and is approximately optimum under decentralized caching.\",\n \"Title: The Role of Caching in Future Communication Systems and Networks.\\nYear: 2018\\n\\nAbstract: This paper has the following ambitious goal: to convince the reader that content caching is an exciting research topic for the future communication systems and networks. Caching has been studied for more than 40 years, and has recently received increased attention from industry and academia. Novel caching techniques promise to push the network performance to unprecedented limits, but also pose sig...\",\n \"Title: Energy and Latency Control for Edge Computing in Dense V2X Networks.\\nYear: 2018\\n\\nAbstract: This study focuses on edge computing in dense millimeter wave vehicle-to-everything (V2X) networks. A control problem is formulated to minimize the energy consumption under delay constraint resulting from vehicle mobility. A tractable algorithm is proposed to solve this problem by optimizing the offloaded computing tasks and transmit power of vehicles and road side units. The proposed dynamic solution can well coordinate the interference without requiring global channel state information, and makes a tradeoff between energy consumption and task computing latency.\",\n \"Title: Content Caching and Delivery in Wireless Radio Access Networks.\\nYear: 2019\\n\\nAbstract: Today’s mobile data traffic is dominated by content-oriented traffic. Caching popular contents at the network edge can alleviate network congestion and reduce content delivery latency. This paper provides a comprehensive and unified study of caching and delivery techniques in wireless radio access networks (RANs) with caches at all edge nodes (ENs) and user equipments (UEs). Three cache-aided RAN architectures are considered: RANs without fronthaul, with dedicated fronthaul, and with wireless fronthaul. It first reviews in a tutorial nature how caching facilitates interference management in these networks by enabling interference cancelation (IC), zero-forcing (ZF), and interference alignment (IA). Then, two new delivery schemes are presented. One is for RANs with dedicated fronthaul, which considers centralized cache placement at the ENs but both centralized and decentralized placement at the UEs. This scheme combines IA, ZF, and IC together with soft-transfer fronthauling. The other is for RANs with wireless fronthaul, which considers decentralized cache placement at all nodes. It leverages the broadcast nature of wireless fronthaul to fetch not only uncached but also cached contents to boost transmission cooperation among the ENs. The numerical results show that both schemes outperform existing results for a wide range of system parameters, thanks to the various caching gains obtained opportunistically.\",\n \"Title: Exploiting Computation Replication for Mobile Edge Computing: A Fundamental Computation-Communication Tradeoff Study.\\nYear: 2019\\n\\nAbstract: Existing works on task offloading in mobile edge computing (MEC) networks often assume a task is executed once at a single edge node (EN). Downloading the computed result from the EN back to the mobile user may suffer long delay if the downlink channel experiences strong interference or deep fading. This paper exploits the idea of computation replication in MEC networks to speed up the downloading phase. Computation replication allows each user to offload its task to multiple ENs for repetitive execution so as to create multiple copies of the computed result at different ENs which can then enable transmission cooperation and hence reduce the communication latency for result downloading. Yet, computation replication may also increase the communication latency for task uploading, despite the obvious increase in computation load. The main contribution of this work is to characterize asymptotically an order-optimal upload-download communication latency pair for a given computation load in a multi-user multi-server MEC network. Analysis shows when the computation load increases within a certain range, the downloading time decreases in an inversely proportional way if it is binary offloading or decreases linearly if it is partial offloading, both at the expense of linear increase in the uploading time.\",\n \"Title: Joint User Activity Detection and Channel Estimation for Temporal-Correlated Massive Access\\nYear: 2021\\n\\nAbstract: This paper studies the temporal-correlated massive access system where a large number of devices communicate with the base station sporadically and continue transmitting data in the adjacent frames in high probability when being active. By exploiting the sparsity and the temporal correlations of the user activities, the joint user activity detection and channel estimation (JUADCE) problem in multiple consecutive frames can be formulated as a dynamic compressed sensing (DCS) problem. Specifically, we formulate a probabilistic model that accounts the statistics of channels and characterizes the evolutions of the user activities by a steady Markov chain. The hybrid generalized approximate message passing (HyGAMP) framework is leveraged to develop a computationally efficient algorithm named HyGAMP-DCS to solve the JUADCE problem. The HyGAMP-DCS algorithm performs channel estimation in the GAMP part and soft user activity information update in the MP part, then exchanges intrinsic information between these two parts for performance enhancement. Simulation results demonstrate that the proposed algorithm can significantly outperform the conventional DCS-based algorithms and the GAMP algorithm which ignores the temporal correlations.\",\n \"Title: Sum-Rate-Distortion Function For Indirect Multiterminal Source Coding In Federated Learning\\nYear: 2021\\n\\nAbstract: One of the main focus in federated learning (FL) is the communication efficiency since a large number of participating edge devices send their updates to the edge server at each round of the model training. Existing works reconstruct each model update from edge devices and implicitly assume that the local model updates are independent over edge devices. In FL, however, the model update is an indirect multi-terminal source coding problem, also called as the CEO problem where each edge device cannot observe directly the gradient that is to be reconstructed at the decoder, but is rather provided only with a noisy version. The existing works do not leverage the redundancy in the information transmitted by different edges. This paper studies the rate region for the indirect multiterminal source coding problem in FL. The goal is to obtain the minimum achievable rate at a particular upper bound of gradient variance. We obtain the rate region for the quadratic vector Gaussian CEO problem under unbiased estimator and derive an explicit formula of the sum-rate-distortion function in the special case where gradient are identical over edge device and dimension. Finally, we analyse communication efficiency of convex Minibatched SGD and non-convex Minibatched SGD based on the sum-rate-distortion function, respectively.\",\n \"Title: Resource Allocation for Deterministic Delay in Wireless Control Networks\\nYear: 2021\\n\\nAbstract: Meeting the high requirements of deterministic transmission in wireless control systems is very challenging, but also very important. In order to improve the determinacy of wireless short packet transmission, we optimize the communication resource required for multi-sensors in the wireless control system in this letter. In particular, we derive the probability of the transmission delay falling wit...\",\n \"Title: Adaptive Clustering-Based Model Aggregation for Federated Learning with Imbalanced Data\\nYear: 2021\\n\\nAbstract: This paper studies the data imbalance issue in federated learning. We propose a new model aggregation method based on adaptive clustering, called weighted clustered federated learning (CFL). At each round of model aggregation, we first cluster the participating edge devices based on the cosine similarity of their local gradients, where the similarity threshold can adapt to the time varying diverge...\",\n \"Title: An Adaptive Distributed Source Coding Design for Distributed Learning\\nYear: 2021\\n\\nAbstract: A major bottleneck in distributed learning is the communication overhead of exchanging intermediate model update parameters between the worker nodes and the parameter server. Existing works reconstruct each model update from worker nodes and implicitly assume that the local model updates are independent over worker nodes. In distributed learning, however, the model update is an indirect multi-term...\",\n \"Title: Coded Caching With Device Computing in Mobile Edge Computing Systems\\nYear: 2021\\n\\nAbstract: Edge caching and computing have been regarded as an efficient approach to tackle the wireless spectrum crunch problem. In this paper, we design a general coded caching with device computing strategy for computational tasks, e.g., virtual reality (VR) rendering, to minimize the average transmission bandwidth under the quality of service guarantee. Because both coded data and stored data can be the ...\",\n \"Title: Joint Design of Hybrid Beamforming and Reflection Coefficients in RIS-Aided mmWave MIMO Systems\\nYear: 2022\\n\\nAbstract: This paper considers a reconfigurable intelligent surface (RIS)-aided millimeter wave (mmWave) downlink communication system where hybrid analog-digital beamforming is employed at the base station (BS). We formulate a power minimization problem by jointly optimizing hybrid beamforming at the BS and the response matrix at the RIS, under the signal-to-interference-plus-noise ratio (SINR) constraints...\",\n \"Title: A Learning Based Branch-and-Bound Algorithm for Single-Group Multicast Beamforming\\nYear: 2021\\n\\nAbstract: Consider the single-group multicast beamforming problem in wireless systems, where a multi-antenna transmitter has a common message intended to a group of users. The problem is known be non-convex and NP-hard except in very few special cases. Traditional optimization-based algorithms either obtain sub-optimal solutions or take exponential complexity to reach the optimum. In this paper, we propose a learning based branch-and-bound (LBB) algorithm to find a near-optimal solution of the quality-of-service (QoS)-constrained multicast beamforming problem with affordable computational complexity. LBB regards the search procedure of the argument-cut based branch-and-bound (AC-BB) algorithm as a sequential decision problem in a binary tree and learns the optimal pruning policy via supervised learning. We propose to apply ensemble learning to train multiple classifiers and then combine them to achieve better performance. To tackle the imbalanced issue, we propose an undersampling-supervised learning method to sample several balanced subsets and train a classifier on each of them. We also show that the computational complexity of LBB is determined by the depth of the binary tree and give its expression in the worst case. Numerical results show that LBB runs significantly faster than AC-BB while achieving nearly the same optimal performance.\",\n \"Title: Millidegree-Level Direction-of-Arrival Estimation and Tracking for Terahertz Ultra-Massive MIMO Systems\\nYear: 2022\\n\\nAbstract: Terahertz (0.1-10 THz) wireless communications are expected to meet 100+ Gbps data rates for 6G communications. Being able to combat the distance limitation with reduced hardware complexity, ultra-massive multiple-input multiple-output (UM-MIMO) systems with hybrid dynamic array-of-subarrays (DAoSA) beamforming are a promising technology for THz wireless communications. However, fundamental challenges in THz DAoSA systems include millidegree-level three-dimensional direction-of-arrival (DoA) estimation and millisecond-level beam tracking with reduced pilot overhead. To address these challenges, an off-grid subspace-based DAoSA-MUSIC and a deep convolutional neural network (DCNN) methods are proposed for DoA estimation. Furthermore, by exploiting the temporal correlations of the channel variation, an augmented DAoSA-MUSIC-T and a convolutional long short-term memory (ConvLSTM) solutions are further developed to realize DoA tracking. Extensive simulations and comparisons on the proposed subspace- and deep-learning-based algorithms are conducted. Results show that both DAoSA-MUSIC and DCNN achieve super-resolution DoA estimation and outperform existing solutions, while DCNN performs better than DAoSA-MUSIC at a high signal-to-noise ratio. Moreover, DAoSA-MUSIC-T and ConvLSTM can capture fleeting DoA variation with an accuracy of 0.1° within milliseconds, and reduce 50% pilot overhead. Compared to DAoSA-MUSIC-T, ConvLSTM can tolerate large angle variation and remain robust over a long duration.\",\n \"Title: Double-Sided Information Aided Temporal-Correlated Massive Access\\nYear: 2022\\n\\nAbstract: This letter considers temporal-correlated massive access, where each device, once activated, is likely to transmit continuously over several consecutive frames. Motivated by that the device activity at each frame is correlated to not only its previous frame but also its next frame, we propose a double-sided information (DSI) aided joint activity detection and channel estimation algorithm based on the approximate message passing (AMP) framework. The DSI is extracted from the estimation results in a sliding window that contains the target detection frame and its previous and next frames. The proposed algorithm demonstrates superior performance over the state-of-the-art methods.\",\n \"Title: Editorial Issue on “Information Theoretic Foundations of Future Communication Systems”\\nYear: 2022\\n\\nAbstract: Information theory, starting with Shannon’s groundbreaking work, has fundamentally shaped the way communication systems are designed and operated. Information theoretic principles form the underpinnings of modern communication networks. This issue explores how new advances in information theory can impact future communication systems. Several papers address issues at the heart of next generation w...\",\n \"Title: Learning-Based Branch-and-Bound for Non-Convex Complex Modulus Constrained Problems With Applications in Wireless Communications\\nYear: 2022\\n\\nAbstract: We consider a class of non-convex complex modulus constrained problems (CMCPs), which has many important applications in signal processing for wireless communications, including multicast beamforming and multi-input multi-output detection. Due to the non-convex constraints, traditional optimization-based algorithms either obtain sub-optimal solutions or take exponential complexity to reach the optimum. In this paper, we propose a learning based branch-and-bound (LBB) algorithm for solving the considered CMCPs. LBB regards the search procedure of the global optimal argument-cut based branch-and-bound (AC-BB) algorithm as a sequential decision problem in a binary tree and learns the optimal pruning policy via supervised learning. We first propose to apply ensemble learning to train multiple classifiers and then combine them to achieve better performance. To tackle the imbalanced issue, we propose an undersampling-supervised learning method to sample several balanced subsets and train a classifier on each of them. We also show that the computational complexity of LBB is determined by the depth of the binary tree and give its expression in the worst case. Finally, we validate the proposed LBB with two classic problems in wireless communications, i.e., multicast beamforming and MIMO detection. Numerical results show that LBB runs significantly faster than AC-BB while achieving nearly the same optimal performance.\",\n \"Title: Characteristics of Channel Eigenvalues and Mutual Coupling Effects for Holographic Reconfigurable Intelligent Surfaces\\nYear: 2022\\n\\nAbstract: As a prospective key technology for the next-generation wireless communications, reconfigurable intelligent surfaces (RISs) have gained tremendous research interest in both the academia and industry in recent years. Only limited knowledge, however, has been obtained about the channel eigenvalue characteristics and spatial degrees of freedom (DoF) of systems containing RISs, especially when mutual coupling (MC) is present between the array elements. In this paper, we focus on the small-scale spatial correlation and eigenvalue properties excluding and including MC effects, for RISs with a quasi-continuous aperture (i.e., holographic RISs). Specifically, asymptotic behaviors of far-field and near-field eigenvalues of the spatial correlation matrix of holographic RISs without MC are first investigated, where the counter-intuitive observation of a lower DoF with more elements is explained by leveraging the power spectrum of the spatial correlation function. Second, a novel metric is proposed to quantify the inter-element correlation or coupling strength in RISs and ordinary antenna arrays. Furthermore, in-depth analysis is performed regarding the MC effects on array gain, effective spatial correlation, and eigenvalue architectures for a variety of element intervals when a holographic RIS works in the radiation and reception mode, respectively. The analysis and numerical results demonstrate that a considerable amount of the eigenvalues of the spatial correlation matrix correspond to evanescent waves that are promising for near-field communication and sensing. More importantly, holographic RISs can potentially reach an array gain conspicuously larger than conventional arrays by exploiting MC, and MC has discrepant impacts on the effective spatial correlation and eigenvalue structures at the transmitter and receiver.\",\n \"Title: Computation Capacity Enhancement by Joint UAV and RIS Design in IoT\\nYear: 2022\\n\\nAbstract: Mobile-edge computing (MEC) networks are facing limited coverage and harsh wireless transmission environments that severely hinder the computation capacity of the Internet-of-Things (IoT) devices. To overcome these issues, this article proposes a novel MEC framework empowered by an unmanned aerial vehicle (UAV) relay and a reconfigurable intelligence surface (RIS). To fully exploit the potentials in terms of computation enhancement brought by the joint UAV and RIS design, we formulate a max–min computation capacity problem via determining the uplink signal detection, active beamforming of UAV, passive beamforming of RIS, time slot partition, computation bits of UAV, and UAV’s trajectory. We develop a concave–convex procedure (CCCP)-based algorithm in an alternating optimization manner over three subproblems to solve the formulated problem. It finds that the CCCP-based algorithm is conducive to decouple the intractable expressions by converting them into new but tractable second-order cone (SOC) constrains. To evaluate the performance of the proposed CCCP-based algorithm, we later design a direct algorithm by exploiting the implicit convexity of the problem. Simulation results demonstrate that the proposed CCCP-based algorithm derives a comparable performance as the direct algorithm, and achieves about 2.57-Mb max-min computation capacity higher compared with the straight flight case, and 8.08-Mb max–min computation capacity higher compared with the case without RIS, which validate the superiority of the joint UAV and RIS design for computation enhancement.\",\n \"Title: Two-Time-Scale Hybrid Proactive and Reactive Edge Caching for Content Delivery Networks\\nYear: 2022\\n\\nAbstract: In content delivery networks (CDNs), there usually exist two types of storage disks named hard disk drive (HDD) and solid state disk (SSD), which have different read speeds and cache sizes. By accounting such a practical hardware structure of CDNs and time-variant content popularity, we propose a novel two-time-scale caching strategy to determine the content placement in HDDs and SSDs. Specifically, we first propose a Stratification and Clustering based Ridge regression model with Laplacian regularization (SCRL) to predict the dynamic content popularity by utilizing both the video feature and user preference. The additional Laplacian regularization improves the prediction performance by leveraging the neighboring information of each video. Based on the predicted results, we then design an efficient hybrid proactive and reactive cache replacement strategy (HPRR) on a two-time-scale basis. Real-world trace-based numerical results show that the proposed prediction and caching strategy can significantly outperform the considered existing methods.\",\n \"Title: Cellular-Connected Multi-UAV MEC Networks: An Online Stochastic Optimization Approach\\nYear: 2022\\n\\nAbstract: In this paper, we consider a mobile edge computing (MEC) network where multiple cellular-connected unmanned aerial vehicles (UAVs) can offload their computation tasks to multiple ground base stations (GBSs). In practice, the UAVs are generally unable to master stochastic information of task arrival and channel changes in advance, which may cause a severe issue in terms of energy consumption. Therefore, we formulate a stochastic optimization problem with the goal of minimizing the average weighted sum energy consumption, by jointly optimizing UAV-GBS associations, communication and computation resource allocation, and three-dimensional (3D) UAV trajectories, during which a velocity-triggered penalty term (VTPT) is designed to suppress a large amount of the energy consumption of the UAVs. To handle the stochastic problem, we propose an online resource allocation and trajectory optimization algorithm with outer and inner structures. The outer structure transforms the original problem to a deterministic one by applying the Lyapunov-based optimization framework. The inner structure solves the obtained deterministic problem via the Lagrange duality method and the successive convex approximation technique, based on the block coordinate descent framework. Numerical results demonstrate that: 1) VTPT dramatically decreases the UAVs’ energy consumption, and 2) the proposed algorithm not only reduces the energy consumption but also ensures the computation queue stability compared with other benchmark schemes.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":189,"string":"189"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13348,"string":"13,348"}}},{"rowIdx":13349,"cells":{"question_id":{"kind":"string","value":"Yuan Chen"},"question":{"kind":"string","value":"Generate an abstract for the title \"Opportunistic overlays: efficient content delivery in mobile ad hoc networks\" using the following items: 1. Content-based publish/subscribe systems\n2. Node mobility\n3. Opportunistic overlays \n4. Dynamically reconfigurable support framework \n5. Optimize end-to-end delays"},"answer":{"kind":"string","value":"Current content-based publish/subscribe systems assume network environments with stable nodes and network topologies. For mobile environments, one resulting problem is a mismatch between static broker topologies and dynamic underlying network topologies. This mismatch will result in inefficiencies in event delivery, especially in mobile ad hoc networks where nodes frequently change their locations. This paper presents a novel middleware approach termed opportunistic overlays, and its dynamically reconfigurable support framework to address such inefficiencies introduced by node mobility in publish/subscribe systems. The opportunistic overlay approach dynamically adapts event dissemination structures (i.e., broker overlays) to changes in physical network topology, in nodes' physical locations, and in network node behaviors, with the goal of optimizing end-to-end delays in event delivery. Runtime adaptations include the dynamic construction of broker overlay networks and changes of mobile clients' assignments to brokers. Experimental results demonstrate that the opportunistic overlay approach is practically applicable and that the performance advantages attained from the use of opportunistic overlays can be substantial."},"correct_answer":{"kind":"string","value":"Current content-based publish/subscribe systems assume network environments with stable nodes and network topologies. For mobile environments, one resulting problem is a mismatch between static broker topologies and dynamic underlying network topologies. This mismatch will result in inefficiencies in event delivery, especially in mobile ad hoc networks where nodes frequently change their locations. This paper presents a novel middleware approach termed opportunistic overlays, and its dynamically reconfigurable support framework to address such inefficiencies introduced by node mobility in publish/subscribe systems. The opportunistic overlay approach dynamically adapts event dissemination structures (i.e., broker overlays) to changes in physical network topology, in nodes' physical locations, and in network node behaviors, with the goal of optimizing end-to-end delays in event delivery. Runtime adaptations include the dynamic construction of broker overlay networks and changes of mobile clients' assignments to brokers. Experimental results demonstrate that the opportunistic overlay approach is practically applicable and that the performance advantages attained from the use of opportunistic overlays can be substantial."},"documents":{"kind":"list like","value":["Title: SLA Decomposition: Translating Service Level Objectives to System Level Thresholds\nYear: 2007\n\nAbstract: In today's complex and highly dynamic computing environments, systems/services have to be constantly adjusted to meet service level agreements (SLAs) and to improve resource utilization, thus reducing operating cost. Traditional design of such systems usually involves domain experts who implicitly translate service level objectives (SLOs) specified in SLAs to system-level thresholds in an ad-hoc manner. In this paper, we present an approach that combines performance modeling with performance profiling to create models that translate SLOs to lower-level resource requirements for each system involved in providing the service. Using these models, the process of creating an efficient design of a system/service can be automated, eliminating the involvement of domain experts. We demonstrate that our approach is practical and that it can be applied to different applications and software architectures. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment the SLAs can be met while improving CPU utilization up to 3 times.","Title: Analysis of cell spectral efficiency in 3GPP LTE systems.\nYear: 2013\n\nAbstract: A novel analytical framework is presented to evaluate resource consumption, error ratio and spectral efficiency on PHY, MAC and RLC layer in 3GPP LTE systems. Thereby, various aspects of the different LTE system layers are modeled: On PHY layer, association of user terminal to a radio access point, probabilistic radio channel states, adaptive modulation and coding, overhead in LTE radio frame, turbo coded M-QAM block error rate, and Chase combining are taken into account. On MAC layer, hybrid-ARQ protocol, resource assignment failure, and feedback misdetection are accounted for. On RLC layer, segmentation of a RLC SDU into several RLC PDUs, selective repeat - ARQ protocol, feedback loss, and timer for upcoming feedback to be waited for are considered. With the framework, various performance criteria can be evaluated: Resource consumption, error ratio and spectral efficiency are assessed as CDF for any location in a cell, multi-cell scenario map with expected value for each location, CDF for a cell, and expected value and percentile for a cell.","Title: Fine-grain stochastic modelling of dynamic power management policies and analysis of their power - latency tradeoffs\nYear: 2009\n\nAbstract: Dynamic power management (DPM) is one of the main system-level low-power techniques for portable devices. This study presents a fine-grain Markov modelling approach that enables accurate analysis of system power and latency characteristics with full consideration of mode switching overheads in both processor and power controller. The new approach also makes it possible to incorporate latency analy...","Title: A fair packet dropping algorithm considering channel condition in diff-serv wireless networks\nYear: 2004\n\nAbstract: Similar to wired networks, appropriate buffer management strategy in wireless networks can manage the buffer efficiently, avoid or relieve congestion, so as to guarantee QoS. Because of unique issues in the wireless channel, strategies in wired networks can not apply directly to wireless network. In this paper, we propose a fair dropping algorithm called DS-CFD (diff-serv supported channel sensitive fair dropping) to decide drop policy in wireless networks when congestion occurs. The algorithm considers both channel condition and fairness so as to achieve tradeoff between throughput and fair services, and we give different level of balance to assured services and best effort services. Another parameter is defined to modify resource allocation between different classes, this parameter is also adaptive with network load. We build a simple model of the algorithm and present simulation results to show the performance improvements.","Title: Stochastic analysis of power, latency and the degree of concurrency\nYear: 2010\n\nAbstract: Concurrent processing has become the default mode of operation in on-chip systems. Silicon has become cheap enough for having hardware facilities to support very large scale concurrent processing on chip. As a result the availability and applicability of power is becoming more of a limiting factor than logic. However, the advantage of parallelism in reducing power consumption will soon become unrealistic because of the limited scope of reducing Vdd beyond threshold voltage, leaving the reduction of concurrency (through the partial shut-down of system blocks) as a realistic means of reducing power consumption when needed. A stochastic modelling approach is presented in this paper which can integrate the degree of concurrency as a parameter into power and latency analysis. This will facilitate a system design and management regime where the degree of concurrency is used as a means of control to achieve power and performance goals.","Title: Energy-efficient virtual machine scheduling in performance-asymmetric multi-core architectures\nYear: 2012\n\nAbstract: Multi-core architectures with asymmetric core performance have recently shown great promise, because applications with different needs can benefit from either the high performance of a fast core or the high parallelism and power efficiency of a group of slow cores. This performance heterogeneity can be particularly beneficial to applications running in virtual machines (VMs) on virtualized servers, which often have different needs and exhibit different performance and power characteristics. Therefore, scheduling VMs on performance-asymmetric multicore architectures can have a great impact on a system's overall energy efficiency. Unfortunately, existing VM managers, such as Xen, have not taken the heterogeneity into account and thus often result in low energy efficiencies. In this paper, we propose a novel VM scheduling algorithm that exploits core performance heterogeneity to optimize the overall system energy efficiency. We first introduce a metric termed energy-efficiency factor to characterize the power and performance behaviors of the applications hosted by VMs on different cores.We then present a method to dynamically estimate the VM's energy-efficiency factors and then map the VMs to heterogeneous cores, such that the energy efficiency of the entire system is maximized. We implement the proposed algorithm in Xen and evaluate it with standard benchmarks on a real testbed. The experimental results show that our solution improves the system energy efficiency (i.e., performance per watt) by 13.5% on average and up to 55% for some benchmarks, compared to the default Xen scheduler.","Title: Ensembl'S 10th Year\nYear: 2010\n\nAbstract: Ensembl (http://www.ensembl.org) integrates genomic information for a comprehensive set of chordate genomes with a particular focus on resources for human, mouse, rat, zebrafish and other high-value sequenced genomes. We provide complete gene annotations for all supported species in addition to specific resources that target genome variation, function and evolution. Ensembl data is accessible in a variety of formats including via our genome browser, API and BioMart. This year marks the tenth anniversary of Ensembl and in that time the project has grown with advances in genome technology. As of release 56 ( September 2009), Ensembl supports 51 species including marmoset, pig, zebra finch, lizard, gorilla and wallaby, which were added in the past year. Major additions and improvements to Ensembl since our previous report include the incorporation of the human GRCh37 assembly, enhanced visualisation and data-mining options for the Ensembl regulatory features and continued development of our software infrastructure.","Title: Video Transmission over Ad Hoc Networks Using Multiple Description Coding and Clustering-based Multiple Paths\nYear: 2007\n\nAbstract: Ad hoc networks are characterized with frequent link failures and network topology change. These features result in a great challenge to transmit video over ad hoc networks. We propose a novel scheme for robust video transmission over ad hoc networks. Video stream is coded by using multiple description coding strategy and then a clustering-based multiple paths algorithm is applied for routing over ad hoc networks. The paper describes the general issues of multiple description coding and the principle of clustering-based multiple paths algorithm. Simulation results clearly demonstrate the effectiveness of this scheme for supporting error resilient video transmission over ad hoc networks.","Title: SML Model-based Management\nYear: 2007\n\nAbstract: Models enable a clear separation between domain knowledge and application-specific details. In the system management arena, there are multiple implementations of model-based system management solutions, but until now, there was no industry-wide agreement on a common language or paradigm to enable interoperability. A new standard has been proposed to describe IT Services, the service modeling language (\"SML\"). While SML enables interoperability, it still poses challenges in terms of scalable model stores, model validation, and use. This paper discusses an architecture for SML model management and validation and describe and evaluate a prototype implementation with a use case on system management of PlanetLab.","Title: On Modulo Linked Graphs\nYear: 2009\n\nAbstract: A graph G is k -linked if G has at least 2k vertices, and for every sequence x 1 ,x 2 ,...,x k ,y 1 ,y 2 ,...,y k of distinct vertices, G contains k pairwise vertex-disjoint paths P 1 ,P 2 ,...,P k such that P i joins x i and y i for i = 1,2,...,k . We say that G is modulo (m 1 ,m 2 ,...,m k )-linked if G is k -linked and, in addition, for any k -tuple (d 1 ,d 2 ,...,d k ) of natural numbers, the paths P 1 ,P 2 ,...,P k can be chosen such that P i has length d i modulo m i for i = 1,2,...,k . Thomassen [15] showed that if each m i is odd and G has sufficiently high connectivity then G is modulo (m 1 ,m 2 ,...,m k )-linked . In this paper, we will prove that when G is $(92\\sum_{i=1}^k m_i-44k)$-connected, where m i is a prime or m i = 1, either G is modulo (2m 1 ,2m 2 ,..., 2m k )-linked or G has a vertex set X of order at most 4k *** 3 such that G *** X is bipartite.","Title: Perfecting vectorized mechanical drawings\nYear: 1996\n\nAbstract: This article describes a system which has been developed to convert scanned engineering drawings into a vectorized file. The vectorized file consists of lines, arcs, and circles and generates a description of paper-based engineering drawings. The scanned engineering drawing is initially vectorized by a system called RENDER using line-tracking and curve-fitting techniques. However, the results obtained after the initial vectorization are not adequate. This paper discusses a post-processing system called P-RENDER which has been developed to further refine the vectorized line drawings and to recreate the drawing with the exact numbers of lines and arcs. Dashed entities are also detected and recreated. For large C- or D-size engineering drawings the refinement algorithm also leads to a considerable reduction in the size of the CAD database.","Title: Implementing Background Net with Knowware System for Personalized Keyword Support\nYear: 2011\n\nAbstract: This article proposes a novel approach that combines user's instant requirement described in keywords with her or his long-term knowledge background to better serve article selection based on personal preference. The knowledge background is represented as a weighted undirected graph called background net that captures the contextual association of words that appear in the articles recommended by the user through incremental learning. With a background net of user constructed, a keyword from the user is personalized to a fuzzy set that represents contextual association of the given keyword to other words involved in the user's background net. An article evaluation with personal preference can be achieved by evaluating similarity between personalized keyword set based on user's background net and a candidate article. The proposed approach makes it possible to construct a search engine optimizer running on the top of search engines to adjust search results, and offer the potential to be integrated with existing search engine techniques to achieve better performance. The target system of personalized article selection can be automatically constructed using Knowware System which is a development tool of KBS for convenient modeling and component reuse.","Title: Device discovery in future service platforms through SIP\nYear: 2012\n\nAbstract: This paper proposes an extension to Session Initiation Protocol (SIP) for contextualized service delivery in a service delivery platform (SDP) that enables device specific multimedia delivery. SIP separates between session establishment and description and is thus, amenable to be extended for advanced implementations which make it an ideal platform for service creation. Device specific multimedia delivery needs rich and flexible device descriptions, and our approach proposes advanced device descriptions through semantic technologies. The proposed SIP extensions have been implemented on a SIP Application Server which functions as SDP in IP Multimedia Subsystem (IMS). The validation of the proposed extensions is shown through an Android SIP client application that acts as a device browser and recommender for different multimedia services to users. An example device user agent (UA) application has also been implemented on a laptop.","Title: More DCCA-secure public-key encryptions from KEM + DEM style hybrid paradigms and some observations on the 'inner-outer' structure\nYear: 2014\n\nAbstract: Detectable Chosen Ciphertext Security DCCA security is a weaker notion than CCA security. An 'inner-outer' structure is shown to build a CCA-secure PKE from a DCCA-secure PKE, a 1-bounded CCA-secure PKE, and a CPA-secure PKE. In this paper, we first show passive security for DEMs is sufficient for achieving DCCA-secure hybrid PKEs both for KEM+DEM and Tag-KEM/DEM paradigms. Then two DCCA-secure PKEs constructed from CCA secure KEMs are presented. In addition, a counter example to show that the 1-bounded CCA secure component in the 'inner-outer' structure cannot be weakened to CPA one is given, and some possible methods for constructing CCA-secure PKEs from DCCA-secure KEMs are discussed.","Title: Body area network for M-health application: demo abstract.\nYear: 2011\n\nAbstract: Body area network, which has great potential in being the main front-end platform of telemedicine and mobile health systems, is currently being heavily developed to keep pace with the continuously rising demand for personalized healthcare. In our system, an entire body area network solution for M-health, including various of body sensors for collecting physiological signals, a cell phone to facilitate the joint processing of spatially and temporally collected medical data from different parts of the body for resource optimization and systematic health monitoring, a server cluster with great data storage capacity, powerful analysis capabilities to provide data storage, data mining and visualization is presented.","Title: A database and API for variation, dense genotyping and resequencing data.\nYear: 2010\n\nAbstract: Advances in sequencing and genotyping technologies are leading to the widespread availability of multi-species variation data, dense genotype data and large-scale resequencing projects. The 1000 Genomes Project and similar efforts in other species are challenging the methods previously used for storage and manipulation of such data necessitating the redesign of existing genome-wide bioinformatics resources.Ensembl has created a database and software library to support data storage, analysis and access to the existing and emerging variation data from large mammalian and vertebrate genomes. These tools scale to thousands of individual genome sequences and are integrated into the Ensembl infrastructure for genome annotation and visualisation. The database and software system is easily expanded to integrate both public and non-public data sources in the context of an Ensembl software installation and is already being used outside of the Ensembl project in a number of database and application environments.Ensembl's powerful, flexible and open source infrastructure for the management of variation, genotyping and resequencing data is freely available at http://www.ensembl.org.","Title: A partial binary tree DEA-DA cyclic classification model for decision makers in complex multi-attribute large-group interval-valued intuitionistic fuzzy decision-making problems.\nYear: 2014\n\nAbstract: This paper proposes the idea of combining ''interest groups'' with the practical decision information to classify the decision makers (DMs) in complex multi-attribute large-group decision-making (CMALGDM) problems in interval-valued intuitionistic fuzzy (IVIF) environment. It constructs a partial binary tree DEA-DA cyclic classification model to achieve the multiple groups' classification of DMs. Not only does this method provide references for the classification of DMs when the decision information is known, but it also lays foundations for DMs' effective weight determination and the aggregation of decision information. First, this paper normalizes all of the cost attributes into benefit attributes to avoid the wrong decision result. Second, it employs the C-OWA operator to transform IVIF number (IVIFN) samples into single-valued samples. With respect to this transformation, this paper provides the corresponding BUM functions of DMs according to their risk attitudes; therefore, the preference information of DMs can be more objectively aggregated. Third, this paper adopts the partial binary tree DEA-DA cyclic classification model to present an accurate classification of DMs. Thus, for each interest group, group members with different interest preferences can be distinguished and distributed to the appropriate groups. Finally, to show the feasibility and validity of the model, we give an illustrative example.","Title: Parallel logic level simulation of VLSI circuits\nYear: 1994\n\nAbstract: In this paper, we study parallel logic level simulation of combinational VLSI Booleannetworks. The simulator is written in Maisie, a simulation language developed at UCLA. Theunique feature of it is that it allows a simulation model to be executed in either conservative oroptimistic modes with minimal changes to the model. It also supports a number of optimizationsto reduce both checkpointing and blocking overheads for the corresponding simulation protocol.Maisie also supports a variety of ...","Title: Tree-ring precipitation records since 1860 at Changling Mountain, China\nYear: 2005\n\nAbstract: Based on analysis of tree-ring data from Changling Mountain at south margin of Tengger Desert, China, the precipitation process since 1860 was reconstructed. Estimated series suggested that south margin of Tengger Desert had underwent two obvious humid periods (1868-1876 and 1932-1939) and two dry periods (1877-1894 and 1924-1932, among which the year 1887 and 1888 were appreciably wet). Power spectrum analyses suggested that the estimated series has significant periodicities of 2.46-2.64a and quasi periodicity of 11.67a. © 2005 IEEE.","Title: Automated Availability Management Driven by Business Policies\nYear: 2007\n\nAbstract: Policy-driven service management helps reduce IT management cost and it keeps the service management aligned with business objectives. While most of the previous research focuses on performance/resource managements, little has been researched in the area of availability management driven by business policies. This is a critically important task in enterprise IT, because a single failure in enterprise IT could cause huge business loss. It is still unclear how we can automate the availability management in a highly dynamic and complex system according to business level objectives for performance and risk attitude/preference. As a consequence, users can not manage the availability/performance ratio to match their risk tolerance. In this paper, we propose a policy-driven approach to automate run-time availability management in IT systems, according to high level availability and performance objectives. We further apply von Neumann-Morgenstern utility theory to deal with users' risk attitude policies, an important class of business policies specific for availability management, and the associated preference structures. Based on the proposed approach, we implement an automated decision engine for availability management. The initial evaluation of the solution illustrates the significance of the policy-driven approach and it demonstrates its applicability for availability management in complex IT environments. This way IT users can customize their availability to the risks tolerable by business objectives.","Title: CpG-discover: A machine learning approach for CpG islands identification from human DNA sequence\nYear: 2009\n\nAbstract: CpG islands (CGIs) play a fundamental role in genome analysis as genomic markers and tumor markers. Identification of potential CGIs has contributed not only to the prediction of promoters of most house-keeping genes and many tissue-specific genes but also to the understanding of the epigenetic causes of cancer. The most current methods for identifying CGIs suffered from various limitations and involved a lot of human intervention for search purpose. In this paper, we implement a HMM-based CGIs identification system, namely CpG-Discover. Experiments have been conducted on the EMBL human DNA database and in comparison with other widely-used tools. The controlled experimental results indicate that our system is a promising tool and has the capability of locating CGIs accurately. In addition, our system has significant differences from other tools in that it avoids the disadvantages of using sliding windows and it reduces the large amount of human intervention needed to search for or to combine potential CGIs (such as, the thresholds of initial density or distance seed). Therefore, given annotated training data set, our system has the adaptability to find other specific nucleotides sequences in DNA.","Title: On the Visualization of Time-Varying Structured Grids Using a 3D Warp Texture\nYear: 2004\n\nAbstract: We present a novel scheme to interactively visualize time-varying scalar fields defined on a structured grid. The underlying approach is to maximize the use of current graphics hardware by using 3D texture mapping. This approach commonly suffers from an expensive voxelization of each time-step as well as from large size of the voxel array approximating each step. Hence, in our scheme, instead of explicitly voxelizing each scalar field, we directly store each time-step as a three dimensional texture in its native form. We create the function that warps a voxel grid into the given structured grid. At rendering time, we reconstruct the function at each pixel using hardware-based trilinear interpolation. The resulting coordinates allow us to compute the scalar value at this pixel using a second texture lookup. For fixed grids, the function remains constant across time-steps and only the scalar field table needs to be re-loaded as a texture. Our new approach achieves excellent performance with relatively low texture memory requirements and low approximation error.","Title: A note on the generalization of parameterized inexact Uzawa method for singular saddle point problems.\nYear: 2014\n\nAbstract: Recently, Zhang and Wang studied the generalized parameterized inexact Uzawa methods (GPIU) for solving singular saddle point problems (Zhang and Wang, 2013 [22]). In this note, we continue to discuss the semi-convergence of GPIU for solving singular saddle point problems, and weaken some semi-convergent conditions.","Title: Capacity planning and power management to exploit sustainable energy\nYear: 2010\n\nAbstract: This paper describes an approach for designing a power management plan that matches the supply of power with the demand for power in data centers. Power may come from the grid, from local renewable sources, and possibly from energy storage subsystems. The supply of renewable power is often time-varying in a manner that depends on the source that provides the power, the location of power generators, and the weather conditions. The demand for power is mainly determined by the time-varying workloads hosted in the data center and the power management policies implemented by the data center. A case study demonstrates how our approach can be used to design a plan for realistic and complex data center workloads. The study considers a data center's deployment in two geographic locations with different supplies of power. Our approach offers greater precision than other planning methods that do not take into account time-varying power supply and demand and data center power management policies.","Title: Renewable and cooling aware workload management for sustainable data centers\nYear: 2012\n\nAbstract: Recently, the demand for data center computing has surged, increasing the total energy footprint of data centers worldwide. Data centers typically comprise three subsystems: IT equipment provides services to customers; power infrastructure supports the IT and cooling equipment; and the cooling infrastructure removes heat generated by these subsystems. This work presents a novel approach to model the energy flows in a data center and optimize its operation. Traditionally, supply-side constraints such as energy or cooling availability were treated independently from IT workload management. This work reduces electricity cost and environmental impact using a holistic approach that integrates renewable supply, dynamic pricing, and cooling supply including chiller and outside air cooling, with IT workload planning to improve the overall sustainability of data center operations. Specifically, we first predict renewable energy as well as IT demand. Then we use these predictions to generate an IT workload management plan that schedules IT workload and allocates IT resources within a data center according to time varying power supply and cooling efficiency. We have implemented and evaluated our approach using traces from real data centers and production systems. The results demonstrate that our approach can reduce both the recurring power costs and the use of non-renewable energy by as much as 60% compared to existing techniques, while still meeting the Service Level Agreements.","Title: A systematic and practical approach to generating policies from service level objectives\nYear: 2009\n\nAbstract: In order to manage a service to meet the agreed upon SLA, it is important to design a service of the required capacity and to monitor the service thereafter for violations at runtime. This objective can be achieved by translating SLOs specified in the SLA into lower-level policies that can then be used for design and enforcement purposes. Such design and operational policies are often constraints on thresholds of lower level metrics. In this paper, we propose a systematic and practical approach that combines fine-grained performance modeling with regression analysis to translate service level objectives into design and operational policies for multi-tier applications. We demonstrate that our approach can handle both request-based and session-based workloads and deal with workload changes in terms of both request volume and transaction mix. We validate our approach using both the RUBiS e-commerce benchmark and a trace-driven simulation of a business-critical enterprise application. These results show the effectiveness of our approach.","Title: Specification-enhanced policies for automated management of changes in IT systems\nYear: 2006\n\nAbstract: Enterprise and grid computing systems are complex and subject to a broad range of changes such as configuration updates, failures, and performance degradations. These changes affect infrastructure elements such as computation and storage nodes, applications, and system management elements such as monitoring infrastructures. Today's best practices in use by system administrators to manage these changes are manual and ad-hoc. In large complex installations, this would lead to high operational costs, broken closed loop automation, and reduced agility. Providing tools and mechanisms to administrators that automate the reaction to these changes is highly desirable and is an active research area. Policy-based management using Event-Condition-Action (ECA) rules is a well-known approach for such automated change management where management actions are executed when specified event-conditions are observed. In complex systems, the interdependence of components generates multiple events when a single change happens causing multiple rules to be triggered. The order of execution of rule actions determines the system behavior necessitating reasoning about execution order. ECA rules do not contain explicit action specifications needed for reasoning and are therefore unsuited for specifying management rules. In this paper, we propose a specification-enhanced ECA model called Event-Condition-Precondition-Action-Postcondition (ECPAP) for designing adaptation rules. ECPAP rules contain action specifications in first order predicate logic enabling us to develop reasoning algorithms to determine enforcement order of multiple rules. The enforcement order is represented as a Boolean Interpreted Petri Net workflow. We introduce a new notion called enforcement semantics that provides guarantees about rule ordering. We have built an adaptation framework using ECPAP model and have demonstrated it for automated change management of Ganglia and HP OpenView monitoring systems. The evaluation of the framework illustrates the significance of the ECPAP model and demonstrates its applicability for managing complex IT environments.","Title: DCCA-Secure Public-Key Encryptions from Hybrid Paradigms\nYear: 2012\n\nAbstract: Detectable Chosen Cipher text Security (DCCA security) is a security notion for Public-Key Encryptions proposed recently in [1]. A DCCA-secure encryption is not necessarily CCA-secure, but dangerous decryption queries can be detected and are not allowed to be requested to the decryption oracle. DCCA-secure schemes may helps in constructing of CCA-secure ones. In this paper, we show there are already DCCA-secure public-key encryptions from popular KEM+DEM style hybrid paradigms, and passive security for DEM is sufficient for achieving DCCA-secure hybrid PKEs both for KEM+DEM and Tag-KEM/DEM paradigms. Furthermore, two DCCA-secure Public-Key schemes constructed from CCA secure KEMs by using hybrid paradigms are presented, which fall outside any of the three cases pointed out in [1].","Title: Probabilistic performance modeling of virtualized resource allocation\nYear: 2010\n\nAbstract: Virtualization technologies enable organizations to dynamically flex their IT resources based on workload fluctuations and changing business needs. However, only through a formal understanding of the relationship between application performance and virtualized resource allocation can over-provisioning or over-loading of physical IT resources be avoided. In this paper, we examine the probabilistic relationships between virtualized CPU allocation, CPU contention, and application response time, to enable autonomic controllers to satisfy service level objectives (SLOs) while more effectively utilizing IT resources. We show that with only minimal knowledge of application and system behaviors, our methodology can model the probability distribution of response time with a mean absolute error of less than 6% when compared with the measured response time distribution. We then demonstrate the usefulness of a probabilistic approach with case studies. We apply basic laws of probability to our model to investigate whether and how CPU allocation and contention affect application response time, correcting for their effects on CPU utilization. We find mean absolute differences of 8-10% between the modeled response time distributions of certain allocation states, and a similar difference when we add CPU contention. This methodology is general, and should also be applicable to non-CPU virtualized resources and other performance modeling problems.","Title: Digital hardware emulation of universal machine and universal line models for real-time electromagnetic transient simulation\nYear: 2012\n\nAbstract: Real-time electromagnetic transient simulation plays an important role in the planning, design, and operation of power systems. Inclusion of accurate and complicated models, such as the universal machine (UM) model and the universal line model (ULM), requires significant computational resources. This paper proposes a digital hardware emulation of the UM and the ULM for real-time electromagnetic transient simulation. It features accurate floating-point data representation, paralleled implementation, and fully pipelined arithmetic processing. The hardware is based on advanced field-programmable gate array (FPGA) using VHDL. A power system transient case study is simulated in real time to validate the design. On a 130-MHz input clock frequency to the FPGA, the achieved execution times for UM and ULM models are 2.5 μs and 1.42 μs, respectively. The captured real-time oscilloscope results demonstrate high accuracy of the emulator in comparison to the offline simulation of the original system in the EMTP-RV software.","Title: Accurate estimation of frequency of a single sinusoid based on downsampling\nYear: 2012\n\nAbstract: A new phase-based approach for frequency estimation of a single cisoid in the presence of additive white noise is proposed in this paper. The main idea is to divide the observed data into a number of segments by downsampling and exploit this new structure for parameter estimation. The maximum likelihood estimator for frequency is then developed, which is shown to be superior to conventional phase-based methods in terms of uniform performance. Computer simulations also illustrate that the mean square frequency error of the proposed scheme can attain Cramér-Rao lower bound for sufficiently high signal-to-noise ratio conditions.","Title: A 2.4-Gsample/s DVFS FFT Processor for MIMO OFDM Communication Systems\nYear: 2008\n\nAbstract: This paper presents a new dynamic voltage and frequency scaling (DVFS) FFT processor for MIMO OFDM applications. By the proposed multimode multipath-delay-feedback (MMDF) architecture, our FFT processor can process 1-8-stream 256-point FFTs or a high-speed 256-point FFT in two processing domains at minimum clock frequency for DVFS operations. A parallelized radix-24 FFT algorithm is also employed to save the power consumption and hardware cost of complex multipliers. Furthermore, a novel open-loop voltage detection and scaling (OLVDS) mechanism is proposed for fast and robust voltage management. With these schemes, the proposed FFT processor can operate at adequate voltage/frequency under different configurations to support the power-aware feature. A test chip of the proposed FFT processor has been fabricated using UMC 90 nm single-poly nine-metal CMOS process with a core area of 1.88 times1.88 mm2 . The SQNR performance of this FFT chip is over 35.8 dB for QPSK/16-QAM modulation. Power dissipation of 2.4 Gsample/s 256-point FFT computations is about 119.7 mW at 0.85 V. Depending on the operation mode, power can be saved by 18%-43% with voltage scaling in TT corner.","Title: A Novel MAC Protocol for Wireless Ad Hoc Networks with Power Control\nYear: 2007\n\nAbstract: Issues such as the hidden and exposed terminal problems and limited traffic carrying capability still remain unsolved in wireless ad hoc networks. In this paper, we present a novel MAC protocol employing power control. Our design mainly focuses on alleviating the problems of the hidden and exposed terminals and enhancing spatial reuse. We introduce an effective power control scheme to facilitate the power negotiation between the source node and the receiver node. Our protocol can collaborate well with high layer protocols such as AODV in the multi-hop scenarios. We implement our protocol in OPNET environment and study the parameters to optimize its performance. Our preliminary simulation results indicate that, with properly chosen parameters, our protocol works well and achieves considerably high performance in both sparse and dense ad hoc networks.","Title: Translating Service Level Objectives to lower level policies for multi-tier services\nYear: 2008\n\nAbstract: Service providers and their customers agree on certain quality of service guarantees through Service Level Agreements (SLA). An SLA contains one or more Service Level Objectives (SLO)s that describe the agreed-upon quality requirements at the service level. Translating these SLOs into lower-level policies that can then be used for design and monitoring purposes is a difficult problem. Usually domain experts are involved in this translation that often necessitates application of domain knowledge to this problem. In this article, we propose an approach that combines performance modeling with regression analysis to solve this problem. We demonstrate that our approach is practical and that it can be applied to different n-tier services. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment, the SLA can be met while improving CPU utilization by up to 3 times.","Title: RCCA Security for KEM+DEM Style Hybrid Encryptions.\nYear: 2012\n\nAbstract: RCCA security is a weaker notion than CCA security, and has been proven to be sufficient for several cryptographic tasks. This paper adapts RCCA security to the most popular hybrid paradigms, KEM+DEM and Tag-KEM/DEM. It is open to construct an RCCA-secure scheme more efficient than CCA-secure ones. In the setting of Tag-KEM, we solve this by presenting a natural RCCA-secure RSA-based Tag-KEM scheme, named as RSA-TKEM, which is more efficient than all existing methods for constructing a CCA-secure RSA-based Tag-KEM scheme. Unfortunately, combining our RSA-TKEM with passive secure one-time pad following Tag-KEM/DEM paradigm yields an RCCA-insecure hybrid encryption. This shows passive security of DEM is not sufficient now, and Tag-KEM/DEM looses its advantage over KEM+DEM. In spite of this and for completeness, we show RCCA secure DEMs are still sufficient to achieve RCCA-secure hybrid encryptions by following Tag-KEM/DEM. In addition, we show RCCA-secure KEM is sufficient for achieving CCA-secure hybrid encryptions. This is done by introducing a new hybrid paradigm, named as KEM/Tag-DEM, where the ciphertext of KEM is used as a tag for Tag-DEM scheme rather than reversely in Tag-KEM/DEM, so that the security of KEM can be weakened to RCCA one. Tag-DEMs can be constructed as efficiently as DEMs, so RCCA-secure KEMs more efficient than CCA-secure ones become more appealing. © 2013 Springer-Verlag Berlin Heidelberg.","Title: Deriving the consequences of genomic variants with the Ensembl API and SNP Effect Predictor\nYear: 2010\n\nAbstract: Summary: A tool to predict the effect that newly discovered genomic variants have on known transcripts is indispensible in prioritizing and categorizing such variants. In Ensembl, a web-based tool (the SNP Effect Predictor) and API interface can now functionally annotate variants in all Ensembl and Ensembl Genomes supported species. Availability: The Ensembl SNP Effect Predictor can be accessed via the Ensembl website at http://www.ensembl.org/. The Ensembl API (http://www.ensembl.org/info/docs/api/api_installation.html for installation instructions) is open source software. Contact:wm2@ebi.ac.uk; fiona@ebi.ac.uk Supplementary information:Supplementary data are available at Bioinformatics online.","Title: A Semi-supervised Method for Classification of Semantic Relation between Nominals\nYear: 2010\n\nAbstract: The task of classifying the semantic relation between two nominals in a sentence is quite challenging due to lack of a large amount of labeled data. Existing models of semantic relation classification were built on either synthetic training data generated from unlabeled data or hand-annotated training data. Meanwhile, previous work showed that the preposition and verb in the sentences indicate important clues to discover the semantic relation between nominals. In this paper we attempt to exploit both labeled and unlabeled data for semantic relation classification under the framework of semi-supervised multi-task learning. Specifically, to improve the generalization performance of a semantic relation classification model, we leverage the information contained in the training signals of multiple related tasks, e.g, prediction of preposition and verb labels. Results on SemEval 2007 task 4 and SemEval 2010 task 8 indicate that semi-supervised multi-task learning method can help semantic relation classification, resulting in comparable or even better performance than the state of art systems in SemEval 2007 task 4.","Title: Java mirrors: building blocks for remote interaction\nYear: 2002\n\nAbstract: The Internet has created new opportunities for remote interaction and collaboration. Scientists and engineers working in geographically different locations remotely visualize the results of their large-scale simulations and their models use real-time information captured by remote instruments. The use of mirrors across the Internet and from mobile devices requires novel capabilities from the Java-based JMOSS mirrors which are described in this paper. The Mirror Object Model views all application-level entities as objects with associated methods and state, even when the application is actually written in Fortran or C. The paper presents an interactive design workbench for the Rapid Tooling Testbed (RTTB).","Title: Low Bit Rate Compression for SAR Image Based on Blocks Reordering and 3D Wavelet Transform\nYear: 2011\n\nAbstract: Due to that there are a large number of similar characteristics in surface structure of the SAR image, a novel SAR image compression algorithm was proposed based on 3D wavelet transform after block reordering. This proposed algorithm consists of four successive steps: divide the image into sub-blocks with equal size, reorder the sub-blocks according to the similarity measured by weighted Euclidean distance to form 3D array, then 3D wavelet transform and 3D-SPIHT coding are employed for encoding. Experimental results of real SAR images show that the proposed method outperforms the traditional wavelet-based SPIHT in terms of PSNR, especially at the low-bit rate.","Title: Decision support for proposal grouping: A hybrid approach using knowledge rule and genetic algorithm\nYear: 2009\n\nAbstract: Proposal grouping is a special procedure in the sponsorship process for research projects. In practice, it is conducted to simplify the following procedure of reviewer assignment. As the proposals grow, this procedure becomes complex. Practical managers spend an increasing amount of time struggling for identifying valid proposals, classifying proposals and partitioning proposals into groups as well as maintaining some control over the quality and composition of the resulting groups. This paper proposes an approach for proposal grouping, in which knowledge rules are designed to deal with proposal identification and proposal classification, and the genetic algorithm is developed to search for the expected groupings. In addition, a corresponding system is designed and developed to support the proposed approach. Compared to the previous manual grouping, the proposed approach significantly reduces the time required for grouping, ensures more diverse group composition, and increases overall grouping quality.","Title: Using procedure recovery approach to exchange feature-based data among heterogeneous CAD systems\nYear: 2009\n\nAbstract: Data exchange is one of key issues in collaborative design. The purpose of feature-based data exchange is that the target model is editable after being exchanged. This is the reason why nowadays feature-based data exchanges become the research focus beyond the traditional geometry-based data exchange. This paper presents a two-stage mechanism to recover a complete modeling process of a parametric CAD mode in source systems. Therefore, what we exchange is the procedure of modeling steps. In target systems, we use the exchanged procedure to simulate a real human to reconstruct the parametric CAD mode in any heterogeneous CAD systems. The proposed method has been tested with case studies among typical CAD systems, such as SolidWorks, UG, Pro/E and Catia.","Title: Feature identification from vectorized mechanical drawings\nYear: 1997\n\nAbstract: Algorithms to identify 2-D geometric features from the vectorized form of a scanned engineering drawing have been developed. These are based on a pattern matching process where the entities present in the vectorized drawing are checked for specific pattern primitives. The pattern primitives present in an entity are compared with the overall direction of the entity to arrive at the 2-D features that are present. A library of 2-D geometric features has been developed for comparative purposes. For 3-D reconstruction and feature recognition a separation reference point is first found in order to group the entities into their respective views, i.e., top, front, and right side view. This separation reference point is then used to transfer the points belonging to the three orthographic views, expressed in the 2-D coordinate system, to a 3-D coordinate system. The 2-D feature recognition algorithm is applied to each of the three views and the 2-D features recognized in each view are combined using a set of matching primitives and matching rules to arrive at the 3-D features present in the component. 3-D features with linear sweep or rotational sweep and uniform thickness can be recognized.","Title: A statistical approach to characterizing the reliability of systems utilizing HBT devices\nYear: 2005\n\nAbstract: This paper describes a statistical approach to simulating the reliability of systems with HBT devices. Compared to the conventional worst-case method, the described approach utilizes statistical reliability information of the HBT individual devices, along with analysis on the critical paths of the system, to provide more accurate and more comprehensive reliability evaluation of the systems utilizing HBT devices.","Title: Linked graphs with restricted lengths\nYear: 2008\n\nAbstract: A graph G is k-linked if G has at least 2k vertices, and for every sequence x\"1,x\"2,...,x\"k,y\"1,y\"2,...,y\"k of distinct vertices, G contains k vertex-disjoint paths P\"1,P\"2,...,P\"k such that P\"i joins x\"i and y\"i for i=1,2,...,k. Moreover, the above defined k-linked graph G is modulo(m\"1,m\"2,...,m\"k)-linked if, in addition, for any k-tuple (d\"1,d\"2,...,d\"k) of natural numbers, the paths P\"1,P\"2,...,P\"k can be chosen such that P\"i has length d\"i modulo m\"i for i=1,2,...,k. Thomassen showed that, for each k-tuple (m\"1,m\"2,...,m\"k) of odd positive integers, there exists a natural number f(m\"1,m\"2,...,m\"k) such that every f(m\"1,m\"2,...,m\"k)-connected graph is modulo(m\"1,m\"2,...,m\"k)-linked. For m\"1=m\"2=...=m\"k=2, he showed in another article that there exists a natural number g(2,k) such that every g(2,k)-connected graph G is modulo(2,2,...,2)-linked or there is X@?V(G) such that |X|==2. Our results generalize several known results on parity-linked graphs.","Title: A hybrid grouping genetic algorithm for reviewer group construction problem\nYear: 2011\n\nAbstract: It is a common task to construct the reviewer group with diverse background between reviewers. This task is complicated considering the multiple criteria and sizable reviewers and groups. However, it has not been clearly addressed in the current studies. This paper investigates this problem and proposes a solution approach. In our study, this problem is firstly formulated as an integrated model that covers the situations of different group number and group size. Then, considering the computational difficulties of solving this model, the grouping genetic algorithm hybridizing the local neighborhood search heuristic is proposed. In the grouping genetic algorithm, the initialization, crossover and mutation are designed according to our problem's characteristics. Extensive numerical experiments show that the proposed algorithm is computationally efficient. Moreover, the application of the proposed algorithm on a case from NSFC also indicates its effectiveness for practical problems.","Title: ECNU: Effective semantic relations classification without complicated features or multiple external corpora\nYear: 2010\n\nAbstract: This paper describes our approach to the automatic identification of semantic relations between nominals in English sentences. The basic idea of our strategy is to develop machine-learning classifiers which: (1) make use of class-independent features and classifier; (2) make use of a simple and effective feature set without high computational cost; (3) make no use of external annotated or unannotated corpus at all. At SemEval 2010 Task 8 our system achieved an F-measure of 75.43% and a accuracy of 70.22%.","Title: Opportunistic channels: mobility-aware event delivery\nYear: 2003\n\nAbstract: The delivery of data in pervasive systems has to deal with end host mobility. One problem is how to create appropriate, application-level data provisioning topologies, termed data brokers, to best match underlying network connectivity, end user locations, and the locales of their network access. Another problem is how to balance workloads in such overlay networks, in response to mobility and to changes in available processing and communication resources. This paper improves the performance of data provisioning by dynamically changing broker topologies and end users' assignments to brokers. Specifically, using publish/subscribe as a communication paradigm, a new abstraction, termed an opportunistic event channel, enables dynamic broker creation, deletion, and movement. Experimental and simulation results demonstrate the ability of opportunistic channels to optimize event delivery and processing when end users move across different network access points. The technique is to 'opportunistically' follow network-level handoffs across network access points with application-level handoffs of a user's broker functionality to a new, 'closer' broker. The potential load imbalances across brokers caused by such handoffs are also addressed. Opportunistic channels are realized with the JECho event infrastructure. Performance advantages attained from their use can be substantial, with the cost of sending a message from a publisher to a mobile subscriber improved by up to 50%. Load balancing improves event delivery even for moderate numbers of event subscribers.","Title: Maximizing server utilization while meeting critical SLAs via weight-based collocation management\nYear: 2013\n\nAbstract: Servers in most data centers are often underutilized due to concerns about SLA violations that may result from resource contention as server utilization increases. This low utilization means that neither the capital investment in the servers nor the power consumed is being used as effectively as it could be. In this demo, we present a novel method for managing the collocation of critical (e.g., user interactive) and non-critical (e.g., batch) workloads on virtualized multicore servers. Unlike previous cap-based solutions, our approach improves server utilization while meeting the SLAs of critical workloads by prioritizing resource access using Linux cgroups weights. We showcase our work conserving collocation method by utilizing a server to nearly 100% while keeping the performance loss of critical workloads within the specified limits.","Title: Effects Of Digital Watermarking On Digital Images\nYear: 2003\n\nAbstract: Digital images are quickly becoming the norm for image capture, storage, or transmission. With physical documents watermarking is used to tag tangible media. Likewise, digital media can also be watermarked. The various reasons for watermarking include: Information hiding, tamper detection, image tagging, and file Access Control. In this paper, we discuss watermarking techniques to 'hide' information in the actual digital image data. However, indiscriminate application of digital watermarking could potentially damage the visual information in a digital image. We analyze three different techniques for watermarking and their affect on the image as we add information. The three types of digital watermarking techniques are investigated in this paper: spatial, frequency, and wavelet domains. Standard digital images are used to investigate, quantitatively and qualitatively, how the image holds the watermark.","Title: Construction of a key-dependent message secure symmetric encryption scheme in the ideal cipher model\nYear: 2014\n\nAbstract: Key-dependent message (KDM) security is an important security issue that has attracted much research in recent years. In this paper, we present a new construction of the symmetric encryption scheme in the the ideal cipher model (ICM); we prove that our scheme is KDM secure against active attacks with respect to arbitrary polynomialtime challenge functions. Our main idea is to introduce a universal hash function (UHF) h as a random value for each encryption, and then use s = h(sk) as the key of the ideal cipher F, where sk is the private key of our symmetric encryption scheme. Although many other schemes that are secure against KDM attacks have already been proposed, in both the ideal standard models, the much more significance of our paper is the simplicity in which we implement KDM security against active attacks.","Title: A 2D-3D Hybrid Approach to Video Stabilization\nYear: 2011\n\nAbstract: In this paper, we introduce a novel 2D-3D hybrid video stabilization method which combines virtues of 2D and 3D video stabilization methods in one routine. It attempts to achieve high-quality camera motions and to retain full frame coherence in each frame, at while, ensure that local regions undergo a similarity transformation. We solve the stabilization problem by integrating 3D and 2D video stabilization methods into one routine. It smooths camera motions and explicitly employs local motion information which constraints video frames to be temporal coherent, and achieves high-quality video stabilization. Experiments show that our method not only can achieve high-quality camera motion on good 3D reconstructed scene, but also can deal with complicated videos containing near, large moving objects.","Title: Object Tracking Using an Improved Kernel Method\nYear: 2008\n\nAbstract: An improved object tracking scheme is presented based on the Kalman filter and mean-shift approach. And this scheme is robust to disturbance and occlusion of both the object and the scene. The object is selected by using FG/BG detection and represented by its center point and probability distribution. The mean-shift approach estimates the object position based on the result of the Kalman filter. A threshold of the Bhattacharyya coefficient is set to judge occlusion and when object being occluded the Kalman filter estimates the object position. Since the proposed scheme combines the space information with probability distribution, it is robust to disturbance and occlusion.","Title: Similarity-guided streamline placement with error evaluation.\nYear: 2007\n\nAbstract: Most streamline generation algorithms either provide a particular density of streamlines across the domain or explicitly detect features, such as critical points, and follow customized rules to emphasize those features. However, the former generally includes many redundant streamlines, and the latter requires Boolean decisions on which points are features (and may thus suffer from robustness problems for real-world data). We take a new approach to adaptive streamline placement for steady vector fields in 2D and 3D. We define a metric for local similarity among streamlines and use this metric to grow streamlines from a dense set of candidate seed points. The metric considers not only Euclidean distance, but also a simple statistical measure of shape and directional similarity. Without explicit feature detection, our method produces streamlines that naturally accentuate regions of geometric interest. In conjunction with this method, we also propose a quantitative error metric for evaluating a streamline representation based on how well it preserves the information from the original vector field. This error metric reconstructs a vector field from points on the streamline representation and computes a difference of the reconstruction from the original vector field.","Title: Realization of interoperation of geographical information in GeoGlobe Service Platform\nYear: 2010\n\nAbstract: One of the purposes of gathering geographic data is to provide better services for the citizens even in their daily life. As the geographical information resources are heterogeneous, it is important to solve the problem of data interoperation and integration. A GeoGlobe Service Platform (GSP) is designed to provide standard and non-standard spatial information service to all levels of government departments via web. In this paper, we mainly introduce the solution of GIS data sharing in GSP, which is based on the standard web services. Some examples of integrating services developed by using GeoGlobe, SuperMap, MapGIS, and ArcGIS software are given.","Title: Approximate Subspace-Based Iterative Adaptive Approach for Fast Two-Dimensional Spectral Estimation\nYear: 2014\n\nAbstract: In this paper, we devise a new approach for fast implementation of two-dimensional (2-D) iterative adaptive approach (IAA) using single or multiple snapshots. Our underlying idea is to apply the subspace methodology in this nonparametric technique by performing the IAA on the dominant singular vectors extracted from the singular value decomposition (SVD) or higher-order SVD of the multidimensional observations. In doing so, 2-D IAA is approximately realized by multiple steps of 1-D IAA, implying that computational attractiveness is achieved particularly for large data size, number of grid points and/or snapshot number. Algorithms based on matrix and tensor operations are developed, and their implementation complexities are analyzed. Computer simulations are also included to compare the proposed approach with the state-of-the-art techniques in terms of resolution probability, spectral estimation performance and computational requirement.","Title: QMON: QoS- and Utility-Aware Monitoring in Enterprise Systems\nYear: 2006\n\nAbstract: The scale, reliability and cost requirements of enterprise data centers require automation of center management. Examples include provisioning, scheduling, capacity planning, logging and auditing. A key component of such automation functions is online monitoring. In contrast to monitoring systems designed for human users, a particular concern for online enterprise monitoring is Quality of Service (QoS). Since breaking service level agreements (SLAs) has direct financial and legal implications, enterprise monitoring must be conducted so as to maintain SLAs. This includes the ability to differentiate the QoS of monitoring itself for different classes of users or more generally, for software components subject to different SLAs. Thus, without embedding notions of QoS into the monitoring systems used in next generation data centers, it will not be possible to accomplish the desired automation of their operation. This paper both demonstrates the importance of QoS in monitoring and it presents a QoS-capable monitoring system, termed QMON. QMON supports utility-aware monitoring while also able to differentiate between different classes of monitoring, corresponding to classes of SLAs. The implementation of QMON offers high levels of predictability for service delivery (i.e., predictable performance) and it is dynamically configurable to deal with changes in enterprise needs or variations in services and applications. We demonstrate the importance of QoS in monitoring and the QoS capabilities of QMON in a series of case studies and experiments, using a multi-tier web service benchmark.","Title: User Model's Realization of the Personalized Service of Digital Library\nYear: 2009\n\nAbstract: The paper represents a kind of user model truss of digital library's personalized service, detailed discusses some key question including express means of user interest model, build of user interest model and renewal arithmetic, lastly based on the personalized text filtrate arithmetic, get the actual validate result of the digital library. The paper represents the express method of vector user model; adopts SVM (support vector machine) and UC (unsupervised clustering) arithmetic combining to pick-up the user interest; adopts LRU (least recently used) arithmetic to realize the renewal of the user interest. The experiment indicated that this model has these characteristic such as adopting implicit mode to acquire user interest and high hit ratio of user mode renewal.","Title: Simulation and analysis of the operating characteristics of MMC based VSC-MTDC system\nYear: 2013\n\nAbstract: With the development of new energy generation, Modular Multilevel Converter (MMC) based HVDC (MMC-HVDC) systems have drawn much attention internationally. This paper focuses on researching the steady and dynamic operating characteristics of an MMC based multi-terminal VSC-HVDC system using the RTDS Simulator. A three-terminal MMC-HVDC system is set up and the operating characteristics of a multi-point DC voltage coordinated control strategy are analyzed. Furthermore, several typical AC and DC contingencies are simulated. The simulation results show that the coordinated control strategy performed well when the MMC-HVDC system operated normally and even when one station was out of service.","Title: MSR-Asia at TREC-10 Video Track: Shot Boundary Detection Task\nYear: 2001\n\nAbstract: The video track is added into TREC-10, composed of two tasks, automatic shot boundary detection and video retrieval. In this year, we (MSR-Asia) participated in the video track, focusing on shot boundary detection task. Our work is to find out all of boundaries the shot changes by a fast algorithm based on uncompressed domain. In our algorithm, all of non-cut transitions are considered as gradual transition, including dissolve, fade-in, fade-out, and all kinds of wipes. Experimental results indicate that the accuracy and processing speed of our algorithm are all very satisfactory.","Title: Fast algorithm for mining global frequent itemsets based on distributed database\nYear: 2006\n\nAbstract: There were some traditional algorithms for mining global frequent itemsets. Most of them adopted Apriori-like algorithm frameworks. This resulted a lot of candidate itemsets, frequent database scans and heavy communication traffic. To solve these problems, this paper proposes a fast algorithm for mining global frequent itemsets, namely the FMGFI algorithm. It can easily get the global frequency for any itemsets from the local FP-tree and require far less communication traffic by the searching strategies of top-down and bottom-up. It effectively reduces existing problems of most algorithms for mining global frequent itemsets. Theoretical analysis and experimental results suggest that the FMGFI algorithm is fast and effective","Title: Active brokers and their runtime deployment in the ECho/JECho distributed event systems\nYear: 2001\n\nAbstract: This paper introduces active brokers and third-party derivation, which is the basic programming construct for run-time remote broker deployment, in the ECho/JECho distributed event systems. We describe its implementation in the JECho system and give examples of using it in ECho/JECho distributed event systems. In particular, we describe the use of third-party derivation in supporting the scalability of content-based event delivery. Specifically, third-party derivation is used both to dynamically construct content-based event distribution trees and to offload potentially expensive client-specific event routing/processing by the run-time creation of remote brokers. Our preliminary benchmark results demonstrate the significant benefits of using third-party derivation.","Title: New Application Of Texture Unit Coding, To Mass Classification For Mammograms\nYear: 2004\n\nAbstract: Texture is one of important features of masses in mammograms. A recent texture Unit-based texture spectrum approach, referred to as Texture Unit Coding (TUC) has shown promise in texture classification. This paper presents a new application of the TUC to mass classification in mammograms. The TUC generates a texture spectrum for a texture image that can be used to describe the characteristics of masses. It also develops an information divergence (ID)-based discrimination criterion to measure the discrepancy between two texture spectra, a concept yet to explore in texture analysis. The TUC along with ID are further applied to mass classification in mammograms where the MiniMammographic Database provided by the Mammographic Image Analysis Society (MIAS) is used for experiments.","Title: The Design of Virtual Self-timed Block for Activity Communication in SOC\nYear: 2007\n\nAbstract: In this paper we present the architecture for virtual self-timed blocks. Being globally asynchronous locally synchronous (GALS) and lazy reactive processing units, such blocks target multi-processing on-chip systems where power consumption is an important factor. The architecture provides a hardware foundation which transparently supports the systematic organization of application-level activities (processes) and the efficient use of system resources. It further facilitates the seamless integration of IP cores into systems by enhancing the GALS paradigm and protecting clocked IP cores from the temporal nondeterminism in their environments. This work includes the basic design of the virtual self-timed block architecture, Matlab models of the important components involved, and demonstrative analyses in Matlab.","Title: Virtual self-timed blocks for systems-on-chip\nYear: 2006\n\nAbstract: Intellectual properties (IP cores) are widely used as pre-designed and reusable units in various system-on-chip (SOC) designs, but their integration has presented difficulties for system designers. In this paper, we propose an approach to better reuse IP cores while maintain energy efficiency for SOC systems. Here we employ a so called self-timed event processor (STEP) to make each IP core into a virtual self-timed block. Much of the IP cores' pre-designed properties can be preserved and the new SOC systems that use virtual self-timed blocks can be more energy efficient. A MATLAB based investigation is carried out on an example STEP processor","Title: NvMap: automated analysis of NMR chemical shift perturbation data.\nYear: 2007\n\nAbstract: NMR chemical shift perturbation experiments are widely used to define binding sites in biomolecular complexes. Especially in the case of high throughput screening of ligands, rapid analysis of NMR spectra is essential. NvMap extends NMRViewJ and provides a means for rapid assignments and book-keeping of NMR titration spectra. Our module offers options to analyze multiple titration spectra both separately and sequentially, where the sequential spectra are analyzed either two at a time or all simultaneously. The first option is suitable for slow or intermediate exchange rates between free and bound proteins. The latter option is particularly useful for fast exchange situations and can compensate for the lack of indicators for overlapped peaks. Our module also provides a simple user interface to automate the analysis process from dataset to peak list. We demonstrate the effectiveness of our program using NMR spectra of SUMO in complexes with three different peptides.NvMap is available on the web at http://www.cityofhope.org/Researchers/ChenYuan/NvMap/ Supplemental information: Manual pages and test spectra will be available on the web at the above site.","Title: Integrated management of application performance, power and cooling in data centers\nYear: 2010\n\nAbstract: Data centers contain IT, power and cooling infrastructures, each of which is typically managed independently. In this paper, we propose a holistic approach that couples the management of IT, power and cooling infrastructures to improve the efficiency of data center operations. Our approach considers application performance management, dynamic workload migration/consolidation, and power and cooling control to “right-provision” computing, power and cooling resources for a given workload. We have implemented a prototype of this for virtualized environments and conducted experiments in a production data center. Our experimental results demonstrate that the integrated solution is practical and can reduce energy consumption of servers by 35% and cooling by 15%, without degrading application performance.","Title: A Generalized Mixed-Radix Algorithm for Memory-Based FFT Processors\nYear: 2010\n\nAbstract: In this brief, a generalized mixed-radix (GMR) algorithm is proposed for memory-based fast Fourier transform (FFT) processors to support prime-sized and traditional 2n -point FFTs simultaneously. It transforms the index to a multidimensional vector for efficient computation. By controlling the index vector to satisfy the ??vector reverse?? behavior, the GMR algorithm can support not only in-place policy for both computation and I/O data for continuous data flow to minimize the memory size but also multibank memory structures to increase the maximum throughput without memory conflict. Finally, a low-complexity implementation of an index vector generator is also proposed for our algorithm.","Title: An Indexed-Scaling Pipelined FFT Processor for OFDM-Based WPAN Applications\nYear: 2008\n\nAbstract: In this brief, a high-throughput and low-complexity fast Fourier transform (FFT) processor for wideband orthogonal frequency division multiplexing communication systems is presented. A new indexed-scaling method is proposed to reduce both the critical-path delay and hardware cost by employing shorter wordlength. Together with the mixed-radix multipath delay feedback structure, the proposed FFT processor can achieve very high throughput with low hardware cost. From analysis, it is shown that the proposed indexed-scaling method can save at least 11% memory utilizations compared to other state-of-the-art scaling algorithms. Also, a test chip of a 1.2 Gsample/s 2048-point FFT processor has been designed using UMC 90-nm 1P9M process with a core area of 0.97 mm2. The signal-to-quantization-noise ratio (SQNR) performance of this test chip is over 32.7 dB to support 16-QAM modulation and the power consumption is about 117 mW at 300 MHz. Compared to the fixed-point FFT processors, about 26% area and 28% power can be saved under the same throughput and SQNR specifications.","Title: A relational debugging engine for the graphics pipeline\nYear: 2005\n\nAbstract: We present a new, unified approach to debugging graphics software. We propose a representation of all graphics state over the course of program execution as a relational database, and produce a query-based framework for extracting, manipulating, and visualizing data from all stages of the graphics pipeline. Using an SQL-based query language, the programmer can establish functional relationships among all the data, linking OpenGL state to primitives to vertices to fragments to pixels. Based on the Chromium library, our approach requires no modification to or recompilation of the program to be debugged, and forms a superset of many existing techniques for debugging graphics software.","Title: Minimizing data center SLA violations and power consumption via hybrid resource provisioning\nYear: 2011\n\nAbstract: This paper presents a novel approach to correctly allocate resources in data centers, such that SLA violations and energy consumption are minimized. Our approach first analyzes historical workload traces to identify long-term patterns that establish a \"base\" workload. It then employs two techniques to dynamically allocate capacity: predictive provisioning handles the estimated base workload at coarse time scales (e.g., hours or days) and reactive provisioning handles any excess workload at finer time scales (e.g., minutes). The combination of predictive and reactive provisioning achieves a significant improvement in meeting SLAs, conserving energy, and reducing provisioning costs. We implement and evaluate our approach using traces from four production systems. The results show that our approach can provide up to 35% savings in power consumption and reduce SLA violations by as much as 21% compared to existing techniques, while avoiding frequent power cycling of servers.","Title: Analysis of Capacity and Error Ratio in 3GPP LTE Systems using Signal Flow Graph Models.\nYear: 2013\n\nAbstract: A novel analytical framework is presented to evaluate capacity and error ratio of different protocol layers in 3GPP LTE systems. Signal flow graphs are used to model various aspects: On PHY layer, association of user terminal to a radio access point, probabilistic radio channel states, adaptive modulation and coding, overhead in LTE radio frame, turbo coded M-QAM block error rate, and Chase combining are taken into account. On MAC layer, hybrid-ARQ, resource assignment failure, and feedback misdetection are accounted for. On RLC layer, segmentation, selective repeat - ARQ, feedback loss, and timer for upcoming feedback are considered.","Title: Hardware Emulation Building Blocks for Real-Time Simulation of Large-Scale Power Grids\nYear: 2014\n\nAbstract: This paper proposes digital hardware building block concept for emulating power system networks on field-programmable gate arrays (FPGAs) in real time. Basic hardware emulation building blocks (HEBBs) for machines, transmission lines, nonlinear elements, and loads are presented to demonstrate how real-time simulation can be achieved for realistic power systems. All of the hardware modules were developed using the VHDL language for portability and extensibility. Employing multiple FPGAs, a large-scale power system consisting of 1260 three-phase buses is modeled in detail in real time to show both electromagnetic transients and electromechanical dynamics in the system. The advantage of HEBB-based modeling is that the design and development of new technologies can be accelerated by utilizing massive real-time digital simulators capable of modeling multiscale and multidomain dynamics.","Title: Qos Contention Control For Optical Coarse Packet Switched Ip-Over-Wdm Network\nYear: 2005\n\nAbstract: In this paper, we first introduce an Optical Coarse Packet Switching (OCPS) paradigm. In principle, OCPS advocates the enforcement of traffic engineering and control to realize bandwidth-on-demand on sub-wavelength basis while circumventing optical packet switching limitations. Based on OCPS, we have constructed an experimental optical IP-over-WDM network testbed, referred to as OPSINET. In the paper, we present the architectural design of OPSINET and its Hybrid Contention Control (HCC) mechanism aiming to satisfy various classes of loss QoS guarantees. The mechanism preventively adopts appropriate burst sizes for different traffic classes during packet burstification at ingress routers. It also reactively performs prioritized contention resolution at OLSRs in the presence of contention. Experimental results show that HCC invariantly achieves low loss probability as a result of burstification-based traffic shaping. Moreover, it provides satisfied loss guarantees for high-priority classes while incurring minimal loss degradation for lower-priority classes.","Title: A Dynamic Pricing Model for E-commerce Based on Data Mining\nYear: 2009\n\nAbstract: In this paper, a dynamic pricing model for e-commerce based on data mining is proposed after the comprehensive analysis of data mining technology applications and e-commerce dynamic pricing strategies. The authors introduce this model into the pricing mechanisms of TaoBao, and discuss the application of the model in C2C and B2C modes, which has great reference value for e-commerce enterprise operation.","Title: AppRAISE: application-level performance management in virtualized server environments\nYear: 2009\n\nAbstract: Managing application-level performance for multitier applications in virtualized server environments is challenging because the applications are distributed across multiple virtual machines, and workloads are dynamic in their intensity and transaction mix resulting in time-varying resource demands. In this paper, we present AppRAISE, a system that manages performance of multi-tier applications by dynamically resizing the virtual machines hosting the applications. We extend a traditional queuing model to represent application performance in virtualized server environments, where virtual machine capacity is dynamically tuned. Using this performance model, AppRAISE predicts the performance of the applications due to workload changes, and proactively resizes the virtual machines hosting the applications to meet performance thresholds. By integrating feedforward prediction and feedback reactive control, AppRAISE provides a robust and efficient performance management solution. We tested AppRAISE using Xen virtual machines and the RUBiS benchmark application. Our empirical results show that AppRAISE can effectively allocate CPU resources to application components of multiple applications to meet end-to-end mean response time targets in the presence of variable workloads, while maintaining reasonable trade-offs between application performance, resource efficiency, and transient behavior.","Title: Application of hybrid logic in inference of Knowware System\nYear: 2010\n\nAbstract: Handling of uncertainty has been an important topic discussed in the community of intelligent techniques and soft computing. It is necessary to represent human knowledge and modeling its uncertainty when developing an intelligent system. There are various types of uncertainty in the real world, and randomness and fuzziness are of two basic kinds. How to handle these two kinds of uncertainties appearing simultaneously in a system is a main task of intelligent system development. The Knowware System (KWS) has been developed as an intelligent tool for modeling and development of knowledge-based system (KBS). It is to support application developers in constructing customized hybrid intelligent system without the necessity of being familiar with relevant AI techniques. Modeling and processing uncertainty of different types has its significance for further enhancement of KWS mechanism to better support real applications. In this paper, we will present the modeling of KBS with possible uncertainty and the propose handling hybrid uncertainty in inference of KWS, which includes randomness and fuzziness, based on the hybrid logic and chance theory.","Title: ℓp-norm based iterative adaptive approach for robust spectral analysis\nYear: 2014\n\nAbstract: Recently, the iterative adaptive approach (IAA) has been shown to be an effective nonparametric methodology for high-resolution spectral analysis. Its main idea is to reformulate the nonlinear frequency estimation problem as a linear model whose parameters are updated iteratively according to weighted least squares. Since the derivation of the IAA is based on @?\"2-norm, it cannot work properly in heavy-tailed noise environment. In this paper, a generalized version of IAA is derived to provide accurate spectral estimation in the presence of impulsive noise, which replaces the @?\"2-norm by the @?\"p-norm where 1","Title: A sixth-order subsampling continuous-time bandpass delta-sigma modulator\nYear: 2005\n\nAbstract: A sixth-order bandpass (BP) delta-sigma modulator (ΔΣM) that uses subsampling relative to the radio frequency (RF) or intermediate frequency (IF) of a receiver, while oversampling the signal bandwidth is described in this paper. The continuous-time (CT) filter that works at RF/IF frequency together with the discrete-time (DT) filter operating at lower frequency provide both noise shaping to quantization noise and subsampling noise. The transfer function derivation with finite Q-factor bandpass filter is analyzed. A pulse-shaped DAC is used to reduce the DAC clock jitter and realize the frequency translation. Because the sampling frequency is much lower than the RF/IF frequency, the complexity and power consumption of the subsequent digital signal processing stage is greatly reduced.","Title: Fuzzy fair packet dropping algorithm supporting differentiated services\nYear: 2005\n\nAbstract: Random Early Detection (RED) is a kind of buffer management algorithms which is widely used in the current Internet. To improve the adaptability and fairness of RED is one of the main tasks of the active queue management. In this paper, the buffer occupancy of individual flow is replaced by a new introduced variable-Sharing Index to indicate the network resource share among different flows, so as to overcome the limitation of buffer occupancy. The definition of Sharing Index in wireless networks is also extended to make it consider both fairness and system performance (channel condition). Through defining rules of both Sharing Index and queue length, a fuzzy logic based buffer management algorithm named FF-RED is proposed. When calculating packet dropping probability in FF-RED algorithm, the probability will further increase or decrease based on the sharing of network resource (by means of Sharing Index), so it can use the difference between flows to make congestion relief more quickly, and it has better adaptability and fairness. Simulation results show that the system performance is improved through using the proposed algorithm.","Title: Random early expiration detection based buffer management algorithm for real-time traffic over wireless networks\nYear: 2005\n\nAbstract: Buffer management algorithms need to decrease queue delay as well as to improve throughput. Because of unique issues in wireless channels, providing delay guarantee in wireless networks is much more complex than that of wired networks. We propose a random early expiration detection based buffer management algorithm for real-time traffic over wireless networks. The main idea is to predict whether new arrival packet can reach the receiver under the limit of maximal delay bound, and random discard the packet based on estimate result, so as to prevent invalid transmission, and at meanwhile to decrease queue delay and to reduce expiration probability of following packets. Considering the characters of wireless link such as variable channel condition and having transmission errors, the algorithm is divided into three stages. We also consider the influence on TCP performance in the design","Title: A smart tracking-based jamming scheme for signals with periodic synchronization sequences.\nYear: 2011\n\nAbstract: In this paper, a smart tracking-based jamming scheme is proposed for the signal with synchronization sequences. A different pseudo-random interference sequence, different from the signal's synchronization sequence, is used to track and interfere with the synchronization header in the original signal. With this known pseudo-random synchronization interference sequence, the interference overlapping on the original signal can be nearly cancelled, meanwhile the original signal can be successfully demodulated and decoded at the own receiver without severe interference. However, the other receivers, directly receiving the hybrid signal composed of the original and the pseudo-random interference signals, will fail to recover the original signal without the knowledge of the pseudo-random interference sequence. Compared with traditional full-band full-time noise blanket jamming in communication countermeasures, the advantages of this smart jamming scheme are its low power consumption and up to 100% chance of successful jamming. Simulation results and hardware implementation both show that this scheme can effectively and essentially interfere with the signal at low power consumption. © 2011 IEEE.","Title: RCCA security for KEM+DEM style hybrid encryptions and a general hybrid paradigm from RCCA-secure KEMs to CCA-secure encryptions\nYear: 2014\n\nAbstract: AbstractReplayable chosen-ciphertext attack RCCA security is a weaker notion than chosen-ciphertext attack CCA security and has been proven to be sufficient for several cryptographic tasks. However, it is open to construct RCCA-secure schemes more efficient than CCA-secure ones. This paper adapts RCCA security to the most popular hybrid paradigms, KEM+DEM and Tag-KEM/DEM. For KEM+DEM paradigm, we show RCCA security is consistent with the CCA case, just as desired. But for Tag-KEM/DEM paradigm, we find some different status. Natural RCCA-secure Tag-KEM schemes can be easily constructed, which are more efficient than all existing CCA-secure ones. But unfortunately, passive security of DEM is not sufficient to obtain RCCA hybrid encryptions. In spite of this and for completeness, we show RCCA-secure DEMs are still sufficient. On the other hand, for passive secure DEMs, we prove that a stronger notion of RCCA security for Tag-KEM, named as tRCCA security, suffices for RCCA-secure hybrid encryptions. This somewhat suggests that a benign RCCA security for tag-based schemes should be tRCCA security. Finally, to show RCCA-secure KEM is sufficient for achieving CCA-secure hybrid encryptions, we introduce a new hybrid paradigm, named as KEM/Tag-DEM, where the ciphertext of KEM is used as a tag for Tag-DEM scheme rather than reversely in Tag-KEM/DEM, so that the security of KEM can be weakened to RCCA one. KEM/Tag-DEM shows the diversity of hybrid encryptions and has additional practical values. We also show Tag-DEMs can be constructed as efficiently as DEMs. Copyright © 2013 John Wiley & Sons, Ltd.","Title: Optimum linear regression in additive Cauchy-Gaussian noise.\nYear: 2015\n\nAbstract: We study the estimation problem of linear regression in the presence of a new impulsive noise model, which is a sum of Cauchy and Gaussian random variables in time domain. The probability density function (PDF) of this mixture noise, referred to as the Voigt profile, is derived from the convolution of the Cauchy and Gaussian PDFs. To determine the linear regression parameters, the maximum likelihood estimator (MLE) is developed first. Since the Voigt profile suffers from a complicated analytical form, an M-estimator with the pseudo-Voigt function is also derived. In our algorithm development, both scenarios of known and unknown density parameters are considered. For the latter case, we estimate the density parameters by utilizing the empirical characteristic function prior to applying the MLE. Simulation results show that the performance of both proposed methods can attain the Cramér–Rao lower bound.","Title: A complex multi-attribute large-group decision making method based on the interval-valued intuitionistic fuzzy principal component analysis model\nYear: 2014\n\nAbstract: In the complex multi-attribute large-group decision making (CMALGDM) problems where attribute values are interval-valued intuitionistic fuzzy numbers (IVIFNs), the number of decision attributes is often large and their correlation degrees are high, which increase the difficulty of decision making and thus influence the accuracy of the result. To solve this problem, this paper proposes the interval-valued intuitionistic fuzzy principal component analysis (IVIF-PCA) model. This model represents major information of original attributes, effectively reduces dimensions of attribute space, and synthesizes original attributes into several relatively independent principal components (PCs). The basic thought of this model is as follows: first, we use thoughts of `equivalency' and `order invariance' to transform IVIFN samples into interval number samples; subsequently, we use the `error theory' to replace interval numbers with their middle points, and combine the middle points with the traditional PCA to obtain the PC scores of interval number samples; finally, we adopt the thought of `equivalency' to obtain the PC scores of IVIFN samples. Moreover, based on the IVIF-PCA model, we give a decision making method for the CMALGDM problem. The feasibility and validity of the decision making method is investigated through a numerical example.","Title: Dynamic Attack Detection in Cyber-Physical Systems with Side Initial State Information.\nYear: 2015\n\nAbstract: This technical note studies the impact of side initial state information on the detectability of data deception attacks against cyber-physical systems. We assume the attack detector has access to a linear function of the initial system state that cannot be altered by an attacker. First, we provide a necessary and sufficient condition for an attack to be undetectable by any dynamic attack detector under each specific side information pattern. Second, we characterize attacks that can be sustained for arbitrarily long periods without being detected. Third, we define the zero state inducing attack, the only type of attack that remains dynamically undetectable regardless of the side initial state information available to the attack detector. Finally, we design a dynamic attack detector that detects detectable attacks.","Title: A two-layer weight determination method for complex multi-attribute large-group decision-making experts in a linguistic environment.\nYear: 2015\n\nAbstract: We propose a two-layer weight determination model in a linguistic environment, when all the clustering results of the experts are known, to objectively obtain expert weights in complex multi-attribute large-group decision-making (CMALGDM) problems. The linguistic information considered in this paper involves both linguistic terms and linguistic intervals. We assume that, for CMALGDM problems, the final expert weights should be determined based on the expert weight in the cluster and on the cluster weights. This is mainly because experts in the same cluster will certainly make varying contributions to the cluster’s overall consensus, and different clusters will also obtain the distinctive “cluster information quality”. Hence, a Minimized Variance Model and an Entropy Weight Model are proposed to determine the expert weights in the cluster and the cluster weights, respectively. We then synthesize these two types of weights into the final objective weights of the CMALGDM experts. The feasibility of the two-layer weight determination model method for the CMALGDM problems is illustrated using a case study of salary reform for professors at a university.","Title: A comparative study on multi-regression analysis and BP neural network of PM2.5 index\nYear: 2014\n\nAbstract: The air pollution PM2.5 index is affected by a variety of factors. The research shows that the PM 2.5 index of yesterday, precipitation of yesterday, average temperature, average humidity, precipitation and wind velocity are the main factors which can affect PM2.5 index. The paper utilizes the data of surface meteorological observation and air pollution PM2.5 index of Wuhan City from November 1, 2013 to January 31, 2014. We construct the air pollution PM2.5 index forecasting model according to multiple regression analysis and BP neural network. The empirical study shows that compared to regression prediction model, BP neural network prediction model obtains the nonlinear relation among the prediction factors after training. The predictive model based on BP neural network is of higher predictive precision and better prediction effect which can be used in kinds of prediction research and has good value to popularize.","Title: Low peak-to-average ratio OFDM chirp waveform diversity design\nYear: 2014\n\nAbstract: Large time-bandwidth product waveform diversity design is a challenging topic in multiple-input multiple-output radar high-resolution imaging because existing methods usually can generate only two large time-bandwidth product waveforms. This paper proposes a new low peak-to-average ratio (PAR) orthogonal frequency division multiplexing chirp waveform diversity design through randomly subchirp modulation. This method can easily yield over two orthogonal large time-bandwidth product waveforms. More waveforms means that more degrees-of-freedom can be obtained for the system. The waveform performance is evaluated by the ambiguity function. It is shown that the designed waveform has the superiorities of a large time-bandwidth product which means high range resolution and low transmit power are allowed for the system, almost constant time-domain and frequency-domain modulus, low PAR and no range-Doppler coupling response in tracking moving targets.","Title: Compressive neighborhood embedding for classification\nYear: 2014\n\nAbstract: Recently, spectral manifold learning algorithms on pattern recognition and machine learning orientation have found wide applications. The common strategy for these algorithms, e.g., Locally Linear Embedding (LLE), facilitates neighborhood relationships which can be constructed by knn or ϵ criterion. This paper presents a simple technique for constructing the nearest neighborhood by combining ℓ2 and ℓ1 norm. The proposed criterion, called Compressive Neighborhood Embedding (CNE), gives rise to a modified spectral manifold learning technique. The validated discriminating power of sparse representation has illuminated in [1], we additionally formulate the semi-supervised learning variation of CNE, SCNE for short, based on the proposed criterion to utilize both labeled and unlabeled data for inference on a graph. Extensive experiments on semi-supervised classification demonstrate the superiority of the proposed algorithm.","Title: Density parameter estimation for additive Cauchy-Gaussian mixture\nYear: 2014\n\nAbstract: In this paper, a mixture noise model, which is a sum of symmetric Cauchy and zero-mean Gaussian random variables in time domain, is studied. The Cauchy and Gaussian distributions are characterized by the unknown median γ and variance σ2, respectively. The probability density function (PDF) and characteristic function (CF) of the mixture are also investigated which are calculated by the convolution of the two PDFs, and product of the two CFs, respectively. Due to the complication of the resultant PDF, typical approaches such as maximum likelihood estimator may not be able to estimate γ and σ2 reliably. Based on the resultant CF, we propose to employ the fractional lower-order moment estimator for their computation. Simulation results show the mean square error performance of the proposed method and a comparison with the Cramér-Rao lower bound is also provided.","Title: Estimation under additive Cauchy-Gaussian noise using Markov chain Monte Carlo\nYear: 2014\n\nAbstract: In this paper, we consider an impulsive mixture noise process, which commonly comes across in applications such as multiuser radar communications, astrophysical imaging in the microwave range and kick detection in oil drilling. The mixture process is in the time domain, whose probability density function (PDF) corresponds to the convolution of the components' PDFs. In this work, we concentrate on the additive mixture of Gaussian and Cauchy PDFs, the convolution of which leads to a Voigt profile. Due to the complicated nature of the PDF, classical methods such as maximum likelihood estimation may be analytically not tractable; therefore, to estimate signals under such noise, we propose using a Markov chain Monte Carlo method, in particular the Metropolis-Hastings algorithm. For illustration, we study the estimation of a ramp function embedded in the Cauchy-Gauss mixture noise, which is motivated by the kick detection problem in oil drilling. Simulation results demonstrate that the mean square error performance of the proposed algorithm can attain the Cramer-Rao lower bound.","Title: ℓ1-norm based nonparametric and semiparametric approaches for robust spectral analysis\nYear: 2014\n\nAbstract: The problem of frequency estimation can be solved by parametric, non-parametric or semi-parametric methods. The representative nonparametric and semiparametric methods, namely, iterative adaptive approach (IAA) and sparse learning via iterative minimization (SLIM) have been recently proposed. Since both of them are not robust to impulsive noise, their extensions, ℓ1-IAA and ℓ1-SLIM are derived to provide accurate spectral estimation in the presence of the heavy-tailed noise in this paper. In our study, the nonlinear frequency estimation problem is mapped to a linear model whose parameters are updated according to the ℓ1-norm and iteratively reweighted least squares. Simulation results are included to demonstrate the outlier resistance performance of the proposed algorithms.","Title: Truncated nuclear norm minimization for tensor completion\nYear: 2014\n\nAbstract: In this paper, a tensor n-mode matrix unfolding truncated nuclear norm is proposed, which is extended from the matrix truncated nuclear norm, to tensor completion problem. The alternating direction method of multipliers is utilized to solve this optimization problem. Meanwhile, the original two-step solution of the matrix truncated nuclear norm is reduced to one step. Employing the intermediate results returned by singular value shrinkage operator, rank information of each tensor unfolding matrix is not required and thus the computational complexity of the devised approach is not demanding. Computer simulation results demonstrate the effectiveness of the proposed method.","Title: A trust routing protocol based on D-S evidence theory in mobile ad hoc network\nYear: 2014\n\nAbstract: Specific to reliability and security issues in mobile ad hoc network, a trust evaluation model based on Dempster-Shafer evidence theory is proposed. Direct trust is calculated with historical interaction information and indirect trust is obtained from neighbor nodes' commendation evidences. The direct trust and indirect trust are combined according to Dempster rule after being amended with weight so as to obtain nodes' comprehensive trust finally. On this basis, optimize the MPR (Multi-Point Relay) technology in Optimized Link State Routing Protocol, an improved routing protocol TOLSR is proposed to reduce the routing overhead. Simulation results show the model can accurately discover and suppress of selfish nodes, thus can effectively improve the reliability of ad hoc network, which also proves the validity and rationality of the trust evaluation model.","Title: Prediction of O-glycosylation sites based on multi-scale composition of amino acids and feature selection.\nYear: 2015\n\nAbstract: Protein glycosylation is one of the most important and complex post-translational modification that provides greater proteomic diversity than any other post-translational modification. Fast and reliable computational methods to identify glycosylation sites are in great demand. Two key issues, feature encoding and feature selection, can critically affect the accuracy of a computational method. We present a new O-glycosylation sites prediction method using only amino acid sequence information. The method includes the following components: (1) on the basis of multi-scale theory, features based on multi-scale composition of amino acids were extracted from the training sequences with identified glycosylation sites; (2) perform a two-stage feature selection to remove features that had adverse effects on the prediction, including a stage one preliminary filtering with Student's t test, and a second stage screening through iterative elimination using novel pairwise comparisons conducted in random subspace using support vector machine. Important features retained are used to build prediction model. The method is evaluated with sequence-based tenfold cross-validation tests on balanced datasets. The results of our experiments show that our method significantly outperforms those reported in the literature in terms of sensitivity, specificity, accuracy, Matthew's correlation coefficient. The prediction accuracy of serine and threonine residues sites reached 95.7 and 92.7 %. The Matthew correlation coefficient of our method for S and T sites is 0.914 and 0.873, respectively. This method can evaluate each feature with the interactions of the rest of the features, which are still included in the model and have the advantage of high efficiency.","Title: New method of key‐dependent message security for asymmetric encryption\nYear: 2015\n\nAbstract: Key-dependent message (KDM) security should be considered in the design of security protocols, especially for complicated ones, where the messages related to the secret key might be encrypted. In this paper, we present a new method of constructing a KDM secure asymmetric encryption scheme with the notation of hybrid encryption in the standard model; although the notation of hybrid encryption was thought as no help to get rid of dependencies between messages and the secret key. Our result can also be seen as a partial instantiation for a previously well-known KDM secure asymmetric encryption scheme based on random oracle. As we know, this has never been carried out before. And our result indicates a new cryptographic application for the primitive of lossy trapdoor function. Throughout the paper, our main idea is to archive KDM security by making use of both leakage-resilience and auxiliary-input security properties. Copyright (c) 2014 John Wiley & Sons, Ltd.","Title: Variance analysis of unbiased least ℓp-norm estimator in non-Gaussian noise.\nYear: 2016\n\nAbstract: Modeling time and space series in various areas of science and engineering require the values of parameters of interest to be estimated from the observed data. It is desirable to analyze the performance of estimators in an elegant manner without the need for extensive simulations and/or experiments. Among various performance measures, variance is the most basic one for unbiased estimators. In this paper, we focus on the estimator based on the ℓp-norm minimization in the presence of zero-mean symmetric non-Gaussian noise. Four representative noise models, namely, α-stable, generalized Gaussian, Student׳s t and Gaussian mixture processes, are investigated, and the corresponding variance expressions are derived for linear and nonlinear parameter estimation problems at p≥1. The optimal choice of p for different noise environments is studied, where the global optimality and sensitivity analyses are also provided. The developed formulas are verified by computer simulations and are compared with the Cramér-Rao lower bound.","Title: Informative gene selection and the direct classification of tumors based on relative simplicity.\nYear: 2016\n\nAbstract: Selecting a parsimonious set of informative genes to build highly generalized performance classifier is the most important task for the analysis of tumor microarray expression data. Many existing gene pair evaluation methods cannot highlight diverse patterns of gene pairs only used one strategy of vertical comparison and horizontal comparison, while individual-gene-ranking method ignores redundancy and synergy among genes.Here we proposed a novel score measure named relative simplicity (RS). We evaluated gene pairs according to integrating vertical comparison with horizontal comparison, finally built RS-based direct classifier (RS-based DC) based on a set of informative genes capable of binary discrimination with a paired votes strategy. Nine multi-class gene expression datasets involving human cancers were used to validate the performance of new method. Compared with the nine reference models, RS-based DC received the highest average independent test accuracy (91.40 %), the best generalization performance and the smallest informative average gene number (20.56). Compared with the four reference feature selection methods, RS also received the highest average test accuracy in three classifiers (Naïve Bayes, k-Nearest Neighbor and Support Vector Machine), and only RS can improve the performance of SVM.Diverse patterns of gene pairs could be highlighted more fully while integrating vertical comparison with horizontal comparison strategy. DC core classifier can effectively control over-fitting. RS-based feature selection method combined with DC classifier can lead to more robust selection of informative genes and classification accuracy.","Title: Computed-torque plus robust adaptive compensation control for robot manipulator with structured and unstructured uncertainties.\nYear: 2016\n\nAbstract: A computed-torque plus robust adaptive compensation control scheme (CTRACC) is proposed for trajectory tracking control of a robot manipulator with uncertain dynamics. To eliminate structured and unstructured uncertainties, an adaptive fuzzy control algorithm and a robust H∞ control mode are incorporated in the conventional computed-torque controller. The adaptive fuzzy control algorithm is employ...","Title: Performance Characteristics and Temperature Compensation Method of Fluid Property Sensor Based on Tuning-Fork Technology.\nYear: 2016\n\nAbstract: Fluid property sensor (FPS) based on tuning-fork technology is applied to the measurement of the contaminant level of lubricant oil. The measuring principle of FPS sensor is derived and proved together with its resolution. The performance characteristics of the FPS sensor, such as sensitivity coefficient, resolution, and quality factor, are analyzed. A temperature compensation method is proposed to eliminate the temperature-dependence of the measuring parameters, and its validity is investigated by numerical simulation of sensitivity, oscillating frequency, and dielectric constant. The values of purification efficiency obtained using microwave and without microwave are compared experimentally.","Title: Deformation Monitoring of Geomechanical Model Test and Its Application in Overall Stability Analysis of a High Arch Dam\nYear: 2015\n\nAbstract: Geomechanical model testing is an important method for studying the overall stability of high arch dams. The main task of a geomechanical model test is deformation monitoring. Currently, many types of deformation instruments are used for deformation monitoring of dam models, which provide valuable information on the deformation characteristics of the prototype dams. However, further investigation is required for assessing the overall stability of high arch dams through analyzing deformation monitoring data. First, a relationship for assessing the stability of dams is established based on the comprehensive model test method. Second, a stability evaluation system is presented based on the deformation monitoring data, together with the relationships between the deformation and overloading coefficient. Finally, the comprehensive model test method is applied to study the overall stability of the Jinping-I high arch dam. A three-dimensional destructive test of the geomechanical model dam is conducted under reinforced foundation conditions. The deformation characteristics and failure mechanisms of the dam abutments and foundation were investigated. The test results indicate that the stability safety factors of the dam abutments and foundation range from 5.2 to 6.0. These research results provide an important scientific insight into the design, construction, and operation stages of this project.","Title: Optimal trajectory planning for glass-handing robot based on execution time acceleration and jerk\nYear: 2016\n\nAbstract: AbstractThis study describes a trajectory planning method based on execution time, acceleration, and jerk to ensure that a glass-handing robot runs smoothly at execution time. The minimised objective function consists of the weighted sum of the square of the integral of the execution time, the integral of the acceleration, and the integral of the jerk, all of which are obtained through the weighted coefficient method. At hree-dimensional kinematics model of the glass-handing robot is then established and nonuniform fifth-order B-splines are used to interpolate its path points. The acceleration and jerk are expressed as functions of time through mathematical simulation. Simulation results show that the designed method for robot trajectory planning not only improves the working efficiency of the glass-handing robot but also ensures that it runs smoothly.","Title: Some Binomial And Trinomial Differentially 4-Uniform Permutation Polynomials\nYear: 2015\n\nAbstract: Permutation polynomials with low differential uniformity are important candidate functions to design substitution boxes of block ciphers. In this paper, we investigate several classes of differential 4-uniform binomial and trinomial permutation polynomials over the finite field F-2(n) of 2(n) elements.","Title: Image denoising by using PDE and GCV in tetrolet transform domain\nYear: 2016\n\nAbstract: The proposed algorithm, which uses partial differential equations (PDE) and generalized cross validation (GCV) theory in the tetrolet transform domain, is used to reduce the noise in an image. Tetrolet transform is applied to decompose the noisy image and GCV theory is used to determine the optimal denoising threshold in the tetrolet transform domain. Then inverse tetrolet transform is used to the modified tetrolet transform coefficients to obtain initial denoising image. PDE model is employed to reduce the block effect which is occurred by only using tetrolet transform to reduce noise, and keeping the edge information. The proposed image denoising algorithm is compared with five similar image denoising algorithms: wavelet transform combined with PDE, contourlet transform combined with PDE, curvelet transform combined PDE, shearlet transform combined with PDE and tetrolet transform combined with PDE, respectively. The experimental results show that comprehensive denoising performance of the proposed algorithm combined with PM1 model (Tetrolet+GCV+PM1) is optimal, especially when PSNR is low. More edges and details can be remained well by the proposed algorithm.","Title: Cyber-Physical Systems: Dynamic Sensor Attacks And Strong Observability\nYear: 2015\n\nAbstract: We study cyber-physical systems subject to dynamic sensor attacks, relating them to the system's strong observability. First, we find necessary and sufficient conditions for an attacker to create a dynamically undetectable sensor attack and relate these conditions to properties of the system dynamics eigenvectors. Next, we provide an index that gives the minimum number of sensors that must be attacked in order for an attack to be undetectable. Finally, we illustrate our results with a numerical example on the Quadruple Tank Process.","Title: Mosaic: Towards City Scale Sensing with Mobile Sensor Networks\nYear: 2015\n\nAbstract: We introduce Mosaic, a mobile sensor network system for city scale sensing. Currently, we focus on accurate PM2.5 measurements. We design and implement low-cost smart sensors for this purpose. Those sensors are specifically designed for moving vehicles such as buses and taxies. The mobile sensing capability of our system enables a wide coverage of a city with a modest number of sensors. We incorporate a three-layer architecture in Mosaic. Mosaic faces many practical challenges which need to be properly addressed, e.g., reliable node hardware and software design, and accurate PM2.5 measurements. We have built three versions of Mosaic nodes. We present a novel data calibration approach combining traditional Artificial Neural Network (ANN) and Support Vector Machines (SVMs). We launch real-world deployments of Mosaic in two main cities in China -- Hangzhou and Ningbo. Our initial efforts show that Mosaic is a feasible approach for city scale sensing and our system can produce highly accurate PM2.5 measurements.","Title: Expanding User Features with Social Relationships in Social Recommender Systems\nYear: 2013\n\nAbstract: Although recommender system has been studied for many years, the research of social recommender system is just beginning. Plenty of information can be used in social networks to improve the performance of recommender system. However, some information is very sparse when used as features. We call this feature sparsity problem. In this paper, we aimed at solving feature sparsity problem. A new strategy was proposed to expand user features by social relationships. Experiments on two real world datasets demonstrated that our method can significantly improve the recommendation performance.","Title: Spectral Efficiency Of Lte With Small Cells And Optimum Association Threshold\nYear: 2014\n\nAbstract: A framework is presented for performance analysis of 3GPP LTE with detailed modeling of PHY, MAC and RLC protocol layers taking decode-and-forward relays and small cells into account. CDFs, expected values and percentiles of resource consumption, error ratio and spectral efficiency on various protocol layers are calculated for any grid point and for cells in a multi-cell scenario, respectively. Association of mobile terminals to a radio access point is controlled by an SINR threshold to find out its optimum w.r.t. cell spectral efficiency and cell edge user spectral efficiency.","Title: Improving Preemptive Scheduling with Application-Transparent Checkpointing in Shared Clusters.\nYear: 2015\n\nAbstract: Modern data center clusters are shifting from dedicated single framework clusters to shared clusters. In such shared environments, cluster schedulers typically utilize preemption by simply killing jobs in order to achieve resource priority and fairness during peak utilization. This can cause significant resource waste and delay job response time. In this paper, we propose using suspend-resume mechanisms to mitigate the overhead of preemption in cluster scheduling. Instead of killing preempted jobs or tasks, our approach uses a system level, application-transparent checkpointing mechanism to save the progress of jobs for resumption at a later time when resources are available. To reduce the preemption overhead and improve job response times, our approach uses adaptive preemption to dynamically select appropriate preemption mechanisms (e.g., kill vs. suspend, local vs. remote restore) according to the progress of a task and its suspend-resume overhead. By leveraging fast storage technologies, such as non-volatile memory (NVM), our approach can further reduce the preemption penalty to provide better QoS and resource efficiency. We implement the proposed approach and conduct extensive experiments via Google cluster trace-driven simulations and applications on a Hadoop cluster. The results demonstrate that our approach can significantly reduce the resource and power usage and improve application performance over existing approaches. In particular, our implementation on the next generation Hadoop YARN platform achieves up to a 67% reduction in resource wastage, 30% improvement in overall job response time times and 34% reduction in energy consumption over the current YARN scheduler.","Title: Joint capacity planning and operational management for sustainable data centers and demand response.\nYear: 2016\n\nAbstract: Reducing costs plays a crucial role in building and operating data centers. Internet service providers such as Facebook and Google spend billions of dollars on capacity expansion and operations of their global data centers. Traditionally, capacity planning for data centers is done separately from operational management, which incurs inefficiency. In fact, operational management has significant impacts on capacity planning. Motivated by this gap, we propose a framework that jointly optimizes both capacity planning and operational management for sustainable data centers and data centers participating in demand response programs. Numerical results based on real-world cases highlight that the proposed framework remarkably reduces up to 50% of total expenditures and 75% of greenhouse gas emissions compared to conventional methods. Additionally, our results show that participations in various demand response programs result in vastly different capacity planning decisions and lead to emission reductions of up to 60%.","Title: Mosaic: A Low-Cost Mobile Sensing System For Urban Air Quality Monitoring\nYear: 2016\n\nAbstract: Air quality monitoring has attracted a lot of attention from governments, academia and industry, especially for PM2.5 due to its significant impact on our respiratory systems. In this paper, we present the design, implementation, and evaluation of Mosaic, a low cost urban PM2.5 monitoring system based on mobile sensing. In Mosaic, a small number of air quality monitoring nodes are deployed on city buses to measure air quality. Current low-cost particle sensors based on light-scattering, however, are vulnerable to airflow disturbance on moving vehicles. In order to address this problem, we build our air quality monitoring nodes, Mosaic-Nodes, with a novel constructive airflow-disturbance design based on a carefully tuned airflow structure and a GPS-assisted filtering method. Further, the buses used for system deployment are selected by a novel algorithm which achieves both high coverage and low computation overhead. The collected sensor data is also used to calculate the PM2.5 of locations without direct measurements by an existing inference model. We apply the Mosaic system in a testing urban area which includes more than 70 point-of-interests. Results show that the Mosaic system can accurately obtain the urban air quality with high coverage and low cost.","Title: Accelerating graph applications on integrated GPU platforms via instrumentation-driven optimizations.\nYear: 2016\n\nAbstract: Integrated GPU platforms are a cost-effective and energy-efficient option for accelerating data-intensive applications. While these platforms have reduced overhead of offloading computation to the GPU and potential for fine-grained resource scheduling, there remain several open challenges. First, substantial application knowledge is required to leverage GPU acceleration capabilities. Second, static application profiling is inadequate for extracting performance from graph applications that exhibit input-dependent, irregular runtime behaviors. Third, naive scheduling of applications on both CPU and GPU devices may degrade performance due to memory contention.\n\nWe describe Luminar, a runtime, profile-guided approach to accelerating applications on integrated GPU platforms. By using efficient dynamic instrumentation, Luminar informs resource scheduling about current workload properties. Luminar engenders up to 40% improvements for irregular, graph-based applications, plus 21-80% improvements in throughput and from 3-60% improvements in energy efficiency when scheduling a mix of applications.","Title: Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems.\nYear: 2018\n\nAbstract: This paper studies an attacker against a cyber-physical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker's probability of being detected is related to the non-negative bias induced by his or her attack on the CPS's detection statistic. We formulate a linear quadratic cost...","Title: Numerical Investigation on Transverse Maneuverability of a Vectored Underwater Vehicle Without Appendage.\nYear: 2016\n\nAbstract: Vectored underwater vehicles (VUVs) are receiving increasing research attention, in part for their maneuverability. In our work, we apply a novel vectored thruster based on a spherical parallel mechanism to an underwater vehicle. We present and calculate the scaling factor based on the vectored thruster's configuration parameters and set up a six DOF kinematic model. We construct a nonlinear dynamic model of the VUV without appendages using the Newton-Euler method. To demonstrate the VUV's transverse maneuverability, we set up a perturbation model in a complex domain using Laplacian transformation, and propose the stability margin of vectored propulsion as a maneuverability index. Many numerical examples are provided to verify the maneuverability of the VUV.","Title: A class of binary cyclic codes with generalized Niho exponents.\nYear: 2017\n\nAbstract: In this paper, a class of binary cyclic codes with three generalized Niho-type nonzeros is introduced. Based on some techniques in solving certain equations over finite fields, the proposed cyclic codes are shown to have six nonzero weights and the weight distribution is also completely determined.","Title: Cyber Physical Attacks With Control Objectives And Detection Constraints\nYear: 2016\n\nAbstract: This paper studies attackers with control objectives and explicit detection constraints against cyber-physical systems. The cyber-physical system is equipped with a Kalman filter and an attack detector that uses the innovations process of the Kalman filter. The attacker performs an integrity attack on the actuators and sensors of the system with the aim of moving the system to a target state under the constraint that the probability of him or her being detected is equal to the false alarm probability of the attack detector. We formulate and solve a constrained optimization problem that gives the optimal sequence of attacks and demonstrate our attack strategy in a numerical example.","Title: A convergent smoothing algorithm for training max -min fuzzy neural networks.\nYear: 2017\n\nAbstract: Abstract In this paper, a smooth function is constructed to approximate the nonsmooth output of max –min fuzzy neural networks (FNNs) and its approximation is also presented. In place of the output of max –min FNNs by its smoothing approximation function, the error function, defining the discrepancy between the actual outputs and desired outputs of max –min FNNs, becomes a continuously differentiable function. Then, a smoothing gradient decent-based algorithm with Armijo–Goldstein step size rule is formulated to train max –min FNNs. Based on the existing convergent result, the convergence of our proposed algorithm can easily be obtained. Furthermore, the proposed algorithm also provides a feasible procedure to solve fuzzy relational equations with max –min composition. Finally, some numerical examples are implemented to support our results and demonstrate that the proposed smoothing algorithm has better learning performance than other two gradient decent-based algorithms.","Title: Kinematics and Singularity Analysis of a Four-Degree-of-Freedom Serial-Parallel Hybrid Manipulator.\nYear: 2017\n\nAbstract: For adapting to the complex working environments of amphibious manipulators, we proposed a serial-parallel hybrid quadruped walking manipulator. We simplified the leg mechanism of the serial-parallel hybrid manipulator as a 2UPU-UPR parallel mechanism, and then analyzed the degree of freedom (DOF) of the parallel mechanism by using the screw theory. The results show that the position of the Y direction and the pose of the Z direction are two independent variables which influence the mechanism movement. We deduced the kinematics inverse solution and the velocity Jacobian matrix of the 2UPU-UPR parallel mechanism. Based on the analysis of the Jacobian matrix, three kinds of kinematic singularities of the 2UPU-UPR parallel mechanism are identified. The results show that the 2UPU-UPR parallel mechanism doesn't have the kinematic inverse singularity, but it has three kinds of kinematic forward singularities and two kinds of combined singularities. Finally, the variation of motorial parameters of this 2UPU-UPR parallel mechanism was discussed by a calculation example.","Title: Retinal vessel delineation using a brain-inspired wavelet transform and random forest.\nYear: 2017\n\nAbstract: This paper presents a supervised retinal vessel segmentation by incorporating vessel filtering and wavelet transform features from orientation scores (OSs), and green intensity. Through an anisotropic wavelet-type transform, a 2D image is lifted to a 3D orientation score in the Lie-group domain of positions and orientations R2S1. Elongated structures are disentangled into their corresponding orientation planes and enhanced via multi-orientation vessel filtering. In addition, scale-selective OSs (in the domain of positions, orientations and scales R2S1R+) are obtained by adding a scale adaptation to the wavelet transform. Features are optimally extracted by taking maximum orientation responses at multiple scales, to represent vessels of changing calibers. Finally, we train a Random Forest classifier for vessel segmentation. Extensive validations show that our method achieves a competitive segmentation, and better vessel preservation with less false detections compared with the state-of-the-art methods.","Title: SkyLens: Visual Analysis of Skyline on Multi-dimensional Data.\nYear: 2018\n\nAbstract: Skyline queries have wide-ranging applications in fields that involve multi-criteria decision making, including tourism, retail industry, and human resources. By automatically removing incompetent candidates, skyline queries allow users to focus on a subset of superior data items (i.e., the skyline), thus reducing the decision-making overhead. However, users are still required to interpret and com...","Title: Concurrent log-structured memory for many-core key-value stores\nYear: 2017\n\nAbstract: AbstractKey-value stores are an important tool in managing and accessing large in-memory data sets. As many applications benefit from having as much of their working state fit into main memory, an important design of the memory management of modern key-value stores is the use of log-structured approaches, enabling efficient use of the memory capacity, by compacting objects to avoid fragmented states.However, with the emergence of thousand-core and peta-byte memory platforms (DRAM or future storage-class memories) log-structured designs struggle to scale, preventing parallel applications from exploiting the full capabilities of the hardware: careful coordination is required for background activities (compacting and organizing memory) to remain asynchronous with respect to the use of the interface, and for insertion operations to avoid contending for centralized resources such as the log head and memory pools.In this work, we present the design of a log-structured key-value store called Nibble that incorporates a multi-head log for supporting concurrent writes, a novel distributed epoch mechanism for scalable memory reclamation, and an optimistic concurrency index. We implement Nibble in the Rust language in ca. 4000 lines of code, and evaluate it across a variety of data-serving workloads on a 240-core cache-coherent server. Our measurements show Nibble scales linearly in uniform YCSB workloads, matching competitive non-log-structured key-value stores for write- dominated traces at 50 million operations per second on 1 TiB-sized working sets. Our memory analysis shows Nibble is efficient, requiring less than 10% additional capacity, whereas memory use by non-log-structured key-value store designs may be as high as 2x.","Title: Compressive Sensing Based Interference Cancellation for Ultra Dense Network.\nYear: 2017\n\nAbstract: In this work, we focus on ultra dense network (UDN) which is widely considered as a key component to increase the spectral efficiency for future mobile networks. For the reason that macro and small cells are operating on the same frequencies to increase spectral efficiency, interference from macro-cells and other small-cell users has an impact which can not be neglected. To cope with this challenge, we proposed a minimum mean square error (MMSE) based algorithm to eliminate interference to protect small cell users from macro and small cell interferences in compressive domain. Then Basis Pursuit De-Noising (BPDN) based algorithm is used to reconstruct the desired signal and lower noise. Simulations show that the proposed solution achieves better performance in recovered signal-to-noise ratio (SNR) and complexity reduction.","Title: Cyber-Physical Attacks With Control Objectives.\nYear: 2018\n\nAbstract: This paper studies attackers with control objectives against cyber-physical systems (CPSs). The goal of the attacker is to counteract the CPS's controller and move the system to a target state while evading detection. We formulate a cost function that reflects the attacker's goals, and, using dynamic programming, we show that the optimal attack strategy reduces to a linear feedback of the attacker...","Title: Calibrating Low-Cost Sensors by a Two-Phase Learning Approach for Urban Air Quality Measurement\nYear: 2018\n\nAbstract: Urban air quality information, e.g., PM2.5 concentration, is of great importance to both the government and society. Recently, there is a growing interest in developing low-cost sensors, installed on moving vehicles, for fine-grained air quality measurement. However, low-cost mobile sensors typically suffer from low accuracy and thus need careful calibration to preserve a high measurement quality. In this paper, we propose a two-phase data calibration method consisting of a linear part and a nonlinear part. We use MLS (multiple least square) to train the linear part, and use RF (random forest) to train the nonlinear part. We propose an automatic feature selection algorithm based on AIC (Akaike information criterion) for the linear model, which helps avoid overfitting due to the inclusion of inappropriate features. We evaluate our method extensively. Results show that our method outperforms existing approaches, achieving an overall accuracy improvement of 16.4% in terms of PM2.5 levels compared with state-of-the-art approach.","Title: Resilient Distributed Estimation Through Adversary Detection.\nYear: 2018\n\nAbstract: This paper studies resilient multiagent distributed estimation of an unknown vector parameter when a subset of the agents is adversarial. We present and analyze a flag raising distributed estimator (FRDE) that allows the agents under attack to perform accurate parameter estimation and detect the adversarial agents. The FRDE algorithm is a consensus+innovations estimator in which agents combine est...","Title: Novel Smooth Hash Proof Systems Based on Lattices.\nYear: 2018\n\nAbstract: As a basic and important primitive, hash proof system can be used to construct many cryptographic schemes and protocols. Therefore, it is significant to instantiate more efficient hash proof systems from various assumptions. Although there are many hash proof systems based on various classical assumptions, only a handful of efficient hash proof systems are known based on post-quantum assumptions. ...","Title: Feedforward fuzzy trajectory compensator with robust adaptive observer at input trajectory level for uncertain multi-link robot manipulators.\nYear: 2017\n\nAbstract: This paper presents an inverse dynamics controller plus feedforward fuzzy trajectory compensator suitable for the trajectory tracking control of uncertain multi-link robot manipulators. To address the issue of unavailable normalization factor, a feedforward fuzzy trajectory compensator is proposed and assembled at the input trajectory level of the inverse dynamics controller rather than at the joint drive torque position. The compensator serving as a low-pass filter is implemented outside the inner control loop by adjusting the desired characteristic trajectory. Due to the nearly unchanged internal control algorithm, the adaptive fuzzy compensator is feasible to implement, and is robust when varying the feedback gain in the inner control loop. Moreover, a robust adaptive fuzzy state observer with loose constraints on the position of uncertain function is designed to assess some unmeasurable state parameters, and a robust term is designed to reduce the influence of the lumped uncertainties. By such design, the observer no longer imposes strict limitations on the position of the nonlinear function and the canonical form of unknown robotic dynamic model. To validate the effectiveness of the proposed controller, simulations and experiments are conducted for a desired characteristic trajectory, and the performance of the proposed controller has been compared with conventional controllers and recently developed controllers to illustrate the usefulness and efficiency of the proposed controller.","Title: Tensor Completion via Generalized Tensor Tubal Rank Minimization Using General Unfolding.\nYear: 2018\n\nAbstract: This letter addresses the problem of tensor completion. The properties of the tensor tubal rank (TTR) and tensor Kronecker rank are first discussed, and then a novel generalized tubal Kronecker decomposition together with a new tensor rank referred to as generalized tensor tubal rank (GTTR) are defined. It is shown that the GTTR is suitable for revealing both the Kronecker and tubal structures of ...","Title: Point error effect on MDPSK space optical communication system\nYear: 2017\n\nAbstract: Bit error rate (BER) performance is an important indicator to measure the quality of a space optical communication system. Phase modulation technology is an increasingly popular modulation format used in such a system as it provides a better BER performance. M-ary differential phase shift keying (MDPSK) is a new format of phase modulation technologies. In this paper, we discuss a situation that point error is the only mechanical system effect on a MDPSK free space optical communication system. We give the BER expression of a MDPSK system under the effect of point error. Then we numerically analyze several link parameters such as transmission power, transmission aperture, divergence angle and receiver diameter. We concentrate on analyzing how each parameter influences the BER performance of the MDPSK system. These research works are of great value for the study of communication quality in a free space optical communication system with MDPSK modulation format.","Title: Anonymous Identity-Based Hash Proof System From Lattices In The Standard Model\nYear: 2018\n\nAbstract: An Identity-Based Hash Proof System (IB-HPS) is a fundamental and important primitive, which is widely adapted to construct a number of cryptographic schemes and protocols, especially for leakage-resilient ones. Therefore it is significant to instantiate IB-HPSs from various assumptions. However, all existing IB-HPSs based on lattices are set only in the random oracle model. Thus, proposing an IB-HPS from lattices in the standard model is an essential and interesting work.In this paper, we introduce a much more compact definition for an anonymous IB-HPS, defining computational indistinguishability of valid/invalid ciphertexts and anonymity of identity simultaneously. Then, through utilizing the technique for delegating a short lattice basis due to Agrawal et al. in CRYPTO 2010 and the property of the smoothing parameter over random lattices, we present a new construction of IB-HPS in the standard model. Furthermore, we show that our new construction is selectively secure and anonymous based on the standard learning with errors (LWE) assumption in the standard model.","Title: Central or peripheral? Cognition elaboration cues' effect on users' continuance intention of mobile health applications in the developing markets.\nYear: 2018\n\nAbstract: •This paper aims to explore factors influencing users’ continuance intention of mobile health applications in developing markets.•We proposed the hypotheses and research model based on the elaboration likelihood model and chose Chinese market as the empirical case.•Both perceived usefulness and trust in app promotes users’ continuance intention. Factors of central route and peripheral route positively influence perceived usefulness and users’ trust in app respectively.•Privacy concern enhances the impact of perceived usefulness on continuance intention and strengthens the effect of trust on continuance intention.","Title: Automatic Test Transition Paths Generation Approach from EFSM Using State Tree.\nYear: 2018\n\nAbstract: Software testing is important in whole software development process. However, software testing is large in scale, long period, which need to spend a lot of manpower, and financial resources. This paper analyzes the situation of automatic test case generation technology, proposes an approach to decompose the extended finite state machine (EFSM) first, then convert it to an extended finite state tree, and automatically calculate the test state transition paths through the tree, finally selects satisfied paths to test according to the test variable data which determined by test requirements. This approach can automatically calculate as few test transition paths as possible to achieve state coverage and path coverage requirements, the generated continuous state transition paths are beneficial to the comprehensive test of the state transition of EFSM. Compared with other automatic test path generation methods of EFSM, our approach can automatically generate fewer test transition paths from EFSM and reduce the test time.","Title: Attack Resilient Distributed Estimation: A Consensus Plus Innovations Approach\nYear: 2018\n\nAbstract: This paper studies fully distributed parameter estimation under sensor attacks. A group of agents make measurements of a bounded parameter and a fraction of the agents' sensor measurements falls under integrity attack. When a sensor is under attack, its measurement can take any value as determined by the attacker. The agents exchange messages over a communication network to ensure that all agents are able to correctly estimate the parameter of interest. This paper presents a consensus+innovations algorithm for attack resilient distributed parameter estimation. The algorithm achieves the same level of resilience as the most resilient centralized estimator if less than half of the agents' sensors are under attack, then all agents correctly estimate the parameter of interest, regardless of the topology of the inter-agent communication network, as long as it is connected. This paper illustrates the performance of the algorithm under adversarial attack through numerical simulations.","Title: Robust Frequency Estimation in Symmetric \\(\\alpha \\) -Stable Noise.\nYear: 2018\n\nAbstract: The symmetric (alpha )-stable (S(alpha )S) noise is commonly encountered in a variety of applications such as wireless communications and image processing. In this work, combining the linear prediction property and (ell _p)-norm minimization, a robust frequency estimator is devised for a complex sinusoid in the presence of the S(alpha )S noise. The proposed algorithm, based on the (ell _p)-norm of the preprocessed linear prediction errors, can be regarded as the outlier-resistant version of the generalized weighted linear prediction frequency estimation approach. Computer simulations are conducted to contrast the performance of the proposed algorithm with three conventional frequency estimators. The results indicate that our method is robust to outliers and nearly optimal compared with Cramer–Rao lower bound.","Title: Tensor Completion Using Kronecker Rank-1 Tensor Train With Application To Visual Data Inpainting\nYear: 2018\n\nAbstract: The problem of data reconstruction with partly sampled elements under a tensor structure, which is referred to as tensor completion, is addressed in this paper. The properties of the rank-1 tensor train decomposition and the tensor Kronecker decomposition are introduced at first, and then the tensor Kronecker rank as well as Kronecker rank-1 tensor train decomposition are defined. The general tensor completion idea is presented following the criterion of minimizing the number of Kronecker rank-1 tensors, which is relaxed to the thresholding problem and the solution is derived. Furthermore, the number of Kronecker rank-1 tensors that the proposed algorithm can retrieve and its complexity order are analyzed. Computer simulations are carried out on real visual data sets and demonstrate that our method yields a superior performance over the state-of-the-art approaches in terms of recovery accuracy and/or computational complexity.","Title: Real-Time FPGA-RTDS Co-Simulator for Power Systems.\nYear: 2018\n\nAbstract: This paper proposes a co-simulation platform using field-programmable gate array (FPGA) and real-time digital simulator (RIDS) for the simulation of large power systems. It combines the advantages of high computational power from FPGA and better modelling flexibility from RIDS together. The FPGA therefore acts as an efficient and economical extension to RIDS especially when simulating large ac systems. One of the significant advantages of the proposed co-simulator is that it avoids the potential interface error existing in the conventional approach of interfacing transient stability program with electromagnetic transient programs. Two key aspects of the proposed co-simulator are discussed: 1) the interface design between FPGA and RIDS and 2) the hardware implementation and expandability of the platform. Two case studies are presented to verify the simulation accuracy and capability of the proposed co-simulator. The first case simulates a two-area four-machine power system with one area simulated in FPGA and the other area in RIDS. Comparisons are made with the case where the complete system is simulated in RIDS. The second case simulates a system of 141 buses in FPGA to demonstrate the simulator's capability in simulating large power systems.","Title: Auto scaling virtual machines for web applications with queueing theory\nYear: 2016\n\nAbstract: With the rapid development of cloud computing in recent years, more and more individuals and corporations use cloud computing platform to deploy their web applications, which can significantly minimize their deployment costs. However, it is observed that the number of accesses to some web application often fluctuates over time, resulting in the so-called peak-valley phenomenon: the amount of reserved resources is often proportional to the peak need of physical resources, while most of the time the amount of required resources is far below the peak load and thus physical servers will be idle for most of the time. To solve this problem, we establish a queuing model M/M/C, which represents infinite source and multi-service window. Based on this queueing model, we can accurately predict the arrival time of each customer, which enables us to calculate the minimum amount of resources that meet the resource needs. Then, we use heuristic algorithms and dynamic programming method to design a Virtual Machine (VM) auto-scaling strategies, including horizontal scaling and vertical scaling. With the proposed model and scaling algorithms, we can make web applications not only meet customer needs, but also use the least amount of resources, improving the resource utilization and minimizing deployment costs. With extensive experiments, we show the proposed model and scaling algorithms can greatly improve resource utilization without sacrificing web application performance.","Title: Updatable Identity-Based Hash Proof System Based on Lattices and Its Application to Leakage-Resilient Public-Key Encryption Schemes.\nYear: 2018\n\nAbstract: Identity-based hash proof system is a basic and important primitive. It is widely utilized to construct cryptographic schemes and protocols that are secure against key-leakage attacks. In this paper, we introduce the concept of updatable identity-based hash proof system, in which the related master secret key and the identity secret key can be updated securely. Then, we instantiate this primitive based on lattices in the standard model. Moreover, we introduce an application of this new primitive by giving a generic construction of leakage-resilient public-key encryption schemes with anonymity. This construction can be considered as the integration of the bounded-retrieval model and the continual leakage model. Compared with the existing leakage-resilient schemes, our construction not only is more efficient but also can resist much more key leakage.","Title: The Design and Implementation of a Real Time Visual Search System on JD E-commerce Platform.\nYear: 2018\n\nAbstract: We present the design and implementation of a visual search system for real time image retrieval on JD.com, the world's third largest and China's largest e-commerce site. We demonstrate that our system can support real time visual search with hundreds of billions of product images at sub-second timescales and handle frequent image updates through distributed hierarchical architecture and efficient indexing methods. We hope that sharing our practice with our real production system will inspire the middleware community's interest and appreciation for building practical large scale systems for emerging applications, such as e-commerce visual search.","Title: A High Performance, Scalable DNS Service for Very Large Scale Container Cloud Platforms.\nYear: 2018\n\nAbstract: Containers and microservices are dominating the world of data center and cloud computing. As the scale, dynamism and complexity grow, the performance of the DNS system in container clusters becomes vital. As the world's third and China's largest e-commerce site by revenue, JD.com runs one of the world's largest Kubernetes container clusters in production. It is imperative that the DNS system can handle extremely high traffic. In this paper, we present ContainerDNS, a high performance DNS system for very large scale container clusters with millions of containers. ContainerDNS maximizes DNS system performance and scalability by optimizing DNS packet processing and using efficient memory and cache management.\n\nContainerDNS has been deployed in JD's container platform with 30,000 servers and 500,000 containers running tens of thousands of services and applications. It improves the maximum throughput from 130,000 to 9,000,000 QPS, a 67X performance boost comparing to existing DNS systems.","Title: Resilient Distributed Estimation: Exponential Convergence Under Sensor Attacks\nYear: 2018\n\nAbstract: This paper studies fully distributed parameter estimation under measurement attacks. A connected network of agents makes measurements of a parameter while an adversary manipulates a subset of the measurements. The goal of the agents is to recover the parameter in the presence of measurement attacks. This paper presents an iterative consensus+innovations algorithm for resilient distributed estimation. The algorithm ensures that all agents correctly recover the parameter of interest, with exponentially fast rate of convergence, so long as less than 3/10 of the agents' measurements are under attack, regardless of the (connected) network topology. We demonstrate the performance of the algorithm through numerical examples.","Title: An adaptive fuzzy sliding mode controller for the depth control of an underactuated underwater vehicle\nYear: 2018\n\nAbstract: An adaptive fuzzy sliding mode controller (AFSMC-A control method combining fuzzy control and sliding mode control; it is an intelligent control method for effective control of complex objects in an uncertain environment.) is proposed for depth control of an underactuated underwater vehicle based on the state-dependent Riccati equation. A proportional integral (PI-The integral action makes the output of the controller proportional to the integral of the deviation, so there is no residual at the end of the excess process, but with the integration effect, the stability is reduced.) control unit is integrated into a sliding mode controller (SMC-Essentially a special kind of nonlinear control, and nonlinearity appears as a control discontinuity.) for its control performance improvements and the steady-state error minimization. The issues on undesirable high frequency chattering in the PI plus SMC are addressed by an adaptive algorithm. A fuzzy controller instead of a switching control section of the robust variable structure is used to ensure the robustness of uncertain systems. Simulation results show that the effective depth control can be accomplished in the presence of various uncertainties.","Title: V-Fuzz: Vulnerability-Oriented Evolutionary Fuzzing.\nYear: 2019\n\nAbstract: Fuzzing is a technique of finding bugs by executing a software recurrently with a large number of abnormal inputs. Most of the existing fuzzers consider all parts of a software equally, and pay too much attention on how to improve the code coverage. It is inefficient as the vulnerable code only takes a tiny fraction of the entire code. In this paper, we design and implement a vulnerability-oriented evolutionary fuzzing prototype named V-Fuzz, which aims to find bugs efficiently and quickly in a limited time. V-Fuzz consists of two main components: a neural network-based vulnerability prediction model and a vulnerability-oriented evolutionary fuzzer. Given a binary program to V-Fuzz, the vulnerability prediction model will give a prior estimation on which parts of the software are more likely to be vulnerable. Then, the fuzzer leverages an evolutionary algorithm to generate inputs which tend to arrive at the vulnerable locations, guided by the vulnerability prediction result. Experimental results demonstrate that V-Fuzz can find bugs more efficiently than state-of-the-art fuzzers. Moreover, V-Fuzz has discovered 10 CVEs, and 3 of them are newly discovered. We reported the new CVEs, and they have been confirmed and fixed.","Title: Double window spectrogram difference method - A blind estimation of frequency-hopping signal for battlefield communication environment.\nYear: 2018\n\nAbstract: In the area of battlefield communication, blindly hopping period and hopping frequency estimation from a series of noisy frequency-hopping (FH) signals is an important research topic. With the use of short-time Fourier transform, an accurate jointly hopping period and hopping frequency estimator, namely, double window spectrogram difference (DWSD), is developed. Simulation results are included to demonstrate the low complexity and superiority of the developed method over several conventional parameter estimators.","Title: Multi-Agent based simulation of Elderly Egress Process and Fall Accident in Senior Apartment Buildings.\nYear: 2018\n\nAbstract: A means of egress from buildings is a critical aspect of building design and an important part of building fire regulations. However, elderly evacuees are often overlooked, being regarded as part of the average population, thereby ignoring the limitations elderly people may have. The computational egress model is a useful tool to evaluate postulated \"what-if\" scenarios, aiming to predict building egress performance under these designated scenarios. This paper first applies Multi-agent Based Simulation (MABS) supported by NetLogo to simulate the evacuation scenarios where evacuees are all elderly people, then statistical analysis is utilized to interpret results, and comparative analysis is conducted to offer some suggestions for egress design and crowd management.","Title: Gait Planning and Simulation Analysis of a New Amphibious Quadruped Robots.\nYear: 2018\n\nAbstract: In order to allow quadruped robots to adapt to the complex working environment in the field of fisheries and aquaculture, a new type of quadruped robot with linear and rotary driving is proposed, and the kinematic inverse solution of the leg of the quadruped robot is deduced. For achieving quadruped robot smooth walking, the straight gait of the quadruped robot is planned according to the stability margin principle of motion, so that the stability margin of the machine is 20 mm when three legs supporting it. The planning gait is simulated by ADAMS software, the kinematics and dynamics analysis of the four main driving mechanisms of the robot leg were carried out, and the feasibility of using the STEP5 driving function to execute the planning gait in the quadruped robot was verified. The theoretical and simulation curve analysis results show that, the quadruped robot according to the planned gait can complete the cycle and have a stable walking. The results of this study can provide a reference for the practical application of the new amphibious quadruped robot in the fields of complex and uneven ground in the field of fisheries and aquaculture to realize exploration, fishing and transportation.","Title: Start-Up Demonstration Tests With the Intent of Equipment Classification for Balanced Systems\nYear: 2019\n\nAbstract: A start-up demonstration test is a mechanism that is often applied to determine the acceptability of equipment. Two new start-up demonstration tests are derived and demonstrated with the intent of equipment classification based on the testing results. The two new tests are called the CSTSCFTF_AMGC and CS\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">(1)</sup>\nCS\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">(1)(2)</sup>\nTF\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">(1)(2)</sup>\nTF\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">(2)</sup>\n_AMGC start-up demonstration tests. By using the finite Markov chain imbedding approach, several probabilistic indexes are presented for the new start-up demonstration tests based on the assumption that the tests are independent and identically distributed cases. Two types of optimization models are formulated and solved for the new start-up demonstration tests. Numerical examples are then presented to demonstrate the new start-up demonstration tests. This basic idea of equipment classification can be easily extended to other traditional start-up demonstration tests.","Title: Accelerating Data Analytics on Integrated GPU Platforms via Runtime Specialization.\nYear: 2018\n\nAbstract: Integrated GPU systems are a cost-effective and energy-efficient option for accelerating data-intensive applications. While these platforms have reduced overhead of offloading computation to the GPU and potential for fine-grained resource scheduling, there remain several open challenges: (1) the distinct execution models inherent in the heterogeneous devices present on such platforms drives the need to dynamically match workload characteristics to the underlying resources, (2) the complex architecture and programming models of such systems require substantial application knowledge to achieve high performance, and (3) as such systems become prevalent, there is a need to extend their utility from running known regular data-parallel applications to the broader set of input-dependent, irregular applications common in enterprise settings. The key contribution of our research is to enable runtime specialization on such integrated GPU platforms by matching application characteristics to the underlying heterogeneous resources for both regular and irregular workloads. Our approach enables profile-driven resource management and optimizations for such platforms, providing high application performance and system throughput. Toward this end, this work proposes two novel schedulers with distinct goals: (a) a device-affinity, contention-aware scheduler that incorporates instrumentation-driven optimizations to improve the throughput of running diverse applications on integrated CPU–GPU servers, and (b) a specialized, affinity-aware work-stealing scheduler that efficiently distributes work across all CPU and GPU cores for the same application, taking into account both application characteristics and architectural differences of the underlying devices.","Title: Enabling Elastic Stream Processing in Shared Clusters\nYear: 2016\n\nAbstract: Distributed data stream processing has become an increasingly popular computational framework due to many emerging applications which require real-time processing of data such as dynamic content delivery and security event analysis. These distributed data stream processing applications are often run on shared, multi-tenant clusters as companies try to consolidate from dedicated clusters for each application (batch and streaming) to a single cluster using a global cluster manager such as Hadoop YARN. In shared cluster environments, guaranteeing the quality of service constraints for throughput and response time for both stream processing applications and batch applications is a significant challenge. Stream processing applications often face an elastic demand where the input rate can vary drastically. The typical solution to solve workload elasticity is to guarantee enough resources to the application, but this solution is not possible when resources are being shared among multiple applications. In this paper, we present an approach for supporting elastic scaling of distributed data stream processing applications and efficiently scheduling and coordinating stream processing with batch processing in shared clusters. Our solution consists of a congestion detection monitor which detects bottlenecks in the streaming system and a global state manager that performs non-disruptive, stateful scaling of streaming applications. We implemented our solution using Storm, a popular stream processing framework, and tested our implementation on a Hadoop YARN cluster using a real-time security event processing workload. Our experimental results show that our solution improves stream processing application throughput by 49% over default Storm while decreasing average request response times by 58%.","Title: Variance Analysis For Least L(P)-Norm Estimator In Mixture Of Generalized Gaussian Noise\nYear: 2017\n\nAbstract: Variance analysis is an important research topic to assess the quality of estimators. In this paper, we analyze the performance of the least l(p)-norm estimator in the presence of mixture of generalized Gaussian (MGG) noise. In the case of known density parameters, the variance expression of the l(p)-norm minimizer is first derived, for the general complex-valued signal model. Since the formula is a function of p, the optimal value of p corresponding to the minimum variance is then investigated. Simulation results show the correctness of our study and the near-optimality of the l(p)-norm minimizer compared with Cramer-Rao lower bound.","Title: Tooth Fracture Detection in Spiral Bevel Gears System by Harmonic Response Based on Finite Element Method\nYear: 2017\n\nAbstract: AbstractSpiral bevel gears occupy several advantages such as high contact ratio, strong carrying capacity, and smooth operation, which become one of the most widely used components in high-speed stage of the aeronautical transmission system. Its dynamic characteristics are addressed by many scholars. However, spiral bevel gears, especially tooth fracture occurrence and monitoring, are not to be investigated, according to the limited published issues. Therefore, this paper establishes a three-dimensional model and finite element model of the Gleason spiral bevel gear pair. The model considers the effect of tooth root fracture on the system due to fatigue. Finite element method is used to compute the mesh generation, set the boundary condition, and carry out the dynamic load. The harmonic response spectra of the base under tooth fracture are calculated and the influence of main parameters on monitoring failure is investigated as well. The results show that the change of torque affects insignificantly the determination of whether or not the system has tooth fracture. The intermediate frequency interval (200 Hz–1000 Hz) is the best interval to judge tooth fracture occurrence. The best fault test region is located in the working area where the system is going through meshing. The simulation calculation provides a theoretical reference for spiral bevel gear system test and fault diagnosis.","Title: Resilient Distributed Estimation: Sensor Attacks.\nYear: 2019\n\nAbstract: This paper studies multi-agent distributed estimation under sensor attacks. Individual agents make sensor measurements of an unknown parameter belonging to a compact set, and, at every time step, a fraction of the agentsu0027 sensor measurements may fall under attack and take arbitrary values. We present the Saturated Innovation Update (SIU) algorithm for distributed estimation resilient to sensor attacks. Under the iterative SIU algorithm, if less than one half of the agent sensors fall under attack, then, all of the agentsu0027 estimates converge at a polynomial rate (with respect to the number of iterations) to the true parameter. The resilience of SIU to sensor attacks does not depend on the topology of the inter-agent communication network, as long as it remains connected. We demonstrate the performance of SIU with numerical examples","Title: The Internet of Things: Secure Distributed Inference.\nYear: 2018\n\nAbstract: The growth in the number of devices connected to the Internet of Things (IoT) poses major challenges in security. The integrity and trustworthiness of data and data analytics are increasingly important concerns in IoT applications. These are compounded by the highly distributed nature of IoT devices, making it infeasible to prevent attacks and intrusions on all data sources. Adversaries may hijack...","Title: Freedericksz Transition in Nematic Liquid Crystal Flows in Dimension Two\nYear: 2018\n\nAbstract: this article we are concerned with the dynamical instability of liquid crystals induced by applied magnetic fields, which is the so-called Freedericksz transition. The model under consideration is the simplified Ericksen-Leslie system for a nematic liquid crystal in a magnetic field. We showed that if the magnetic field strength exceeds a threshold, any global solution converges exponentially to a unique nontrivial equilibrium solution. Here we also imposed certain initial and strong anchoring boundary conditions. It is also proved that below the threshold, the asymptotic limit is the trivial state.","Title: A PSO-Based Ensemble Model for Peer-to-Peer Credit Scoring\nYear: 2018\n\nAbstract: We propose a multi-classifier ensemble model based on particle swarm optimization (PSO) for the evaluation of personal credit risk in peer-to-peer (P2P) lending platforms. In the proposed method, we consider the differences and complementarity of the base classifiers' performance and use PSO to optimize their weights. Experimental results show that our proposed P2P personal credit scoring model outperforms both single and other benchmark ensemble models. Among the examined model variants, the ensemble model based on PSO with 100 particles is the best.","Title: Research on personalized recommendation algorithm based on user preference in mobile e-commerce\nYear: 2020\n\nAbstract: With the development of Internet, the problem of information overload becomes more and more serious. The personalized recommendation technology can establish user files through the user’s behavior and other information, and automatically recommend the items that best match the user’s preferences, thus effectively reducing the information overload problem. Based on this, this paper studies the personalized recommendation algorithm based on user preferences in mobile e-commerce. In this paper, user preference model under UTA algorithm is constructed on the basis of user rating on multiple criteria of the project, and user preference clustering is used to improve the scalability problem of personalized recommendation. Finally, the simulation is conducted according to the proposed personalized recommendation algorithm based on user preference. The simulation data use the multi-criteria rating data from 6078 users of Yahoo! Movies website for 976 movies (including 62,156 rows of data). The experimental results show that the multi-criteria recommendation algorithm (MC-CF-dis), which uses user distance similarity, has the best effect, and the MAE and RMSE value of this algorithm is about 1.2 lower than that of the other three algorithms. Accuracy is 6–10% higher than other algorithms. Thus, using this personalized recommendation algorithm based on user preference can effectively improve the quality of recommendation.","Title: ?-Diagnosis: Unsupervised and Real-time Diagnosis of Small- window Long-tail Latency in Large-scale Microservice Platforms\nYear: 2019\n\nAbstract: Microservice architectures and container technologies are broadly adopted by giant internet companies to support their web services, which typically have a strict service-level objective (SLO), tail latency, rather than average latency. However, diagnosing SLO violations, e.g., long tail latency problem, is non-trivial for large-scale web applications in shared microservice platforms due to million-level operational data and complex operational environments. \n\nWe identify a new type of tail latency problem for web services, small-window long-tail latency (SWLT), which is typically aggregated during a small statistical window (e.g., 1-minute or 1-second). We observe SWLT usually occurs in a small number of containers in microservice clusters and sharply shifts among different containers at different time points. To diagnose root-causes of SWLT, we propose an unsupervised and low-cost diagnosis algorithm-?-Diagnosis, using two-sample test algorithm and ?-statistics for measuring similarity of time series to identify root-cause metrics from millions of metrics. We implement and deploy a real-time diagnosis system in our real-production microservice platforms. The evaluation using real web application datasets demonstrates that ?-Diagnosis can identify all the actual root-causes at runtime and significantly reduce the candidate problem space, outperforming other time-series distance based root-cause analysis algorithms.","Title: Selective Range Iterative Adaptive Approach for High-Resolution DOA Estimation.\nYear: 2019\n\nAbstract: In this paper, the problem of direction-of-arrival (DOA) estimation for a uniform linear array with single-snapshot observations is addressed. Two non-parametric DOA estimators are developed, which can be applied in any azimuth range with one snapshot. Their main idea is iteratively updating the DOA estimates using the weighted least squares and covariance matrix. Two criteria for implementing the covariance matrix are devised, which guarantee high resolution of the proposed methods. The simulation results are included to demonstrate the superiority of our algorithms over several conventional DOA methods in terms of both estimation performance and computational complexity.","Title: Triple-Cycle Permutations Over Finite Fields Of Characteristic Two\nYear: 2019\n\nAbstract: Triple-cycle permutations over finite fields of characteristic two are studied, and some classes of triple-cycle permutations are proposed in this paper. In addition, new triple-cycle permutations can be constructed by switching construction from known ones.","Title: A New Mathematical Modeling Method for Four-Stage Helicopter Main Gearbox and Dynamic Response Optimization.\nYear: 2019\n\nAbstract: A new mathematical modeling method, namely, the finite element method and the lumped mass method (LMM-FEM) mixed modeling, is applied to establish the overall multinode dynamic model of a four-stage helicopter main gearbox. The design of structural parameters of the shaft is the critical link in the four-stage gearbox; it affects the response of multiple input and output branches; however, only the meshing pairs were frequently shown in the dynamic model in previous research. Therefore, each shaft is also treated as a single node and the shaft parameters are coupled into the dynamic equations in this method, which is more accurate for the transmission chain. The differential equations of the system are solved by the Fourier series method, and the dynamic response of each meshing element is calculated. The sensitivity analysis method and parameter optimization method are applied to obtain the key shaft parameters corresponding to each meshing element. The results show that the magnitude of dynamic response in converging meshing pair and tail output pair is higher than that of other meshing pairs, and the wall thickness has great sensitivity to a rotor shaft. In addition, the sensitivity analysis method can be used to select the corresponding shaft node efficiently and choose parameters appropriately for reducing the system response.","Title: Tunnel crack detection using coarse‐to‐fine region localization and edge detection\nYear: 2019\n\nAbstract: Detecting cracks on the concrete surface is crucial for the tunnel health monitoring and maintenance of Chinese transport facilities, since it is closely related with the structural health and reliability. The automated and efficient tunnel crack detection recently has attracted more research studies, particularly cheap availability of digital cameras makes this issue easier. However, it is still a challenging task due to concrete blebs, stains, and illumination over the concrete surface. This paper presents an efficient crack detection method in the tunnel concrete structure based on digital image processing and deep learning. Three contributions of the paper are summarized as follows. First, we collect and annotate a tunnel crack dataset including three kinds of common cracks that might benefit the research in the field. Second, we propose a new coarse-to-fine crack detection method using improved preprocessing, coarse crack region localization and classification, and fine crack edge detection. Third, we introduce a faster region convolutional neural network to develop a coarse crack region localization and classification, then deploy edge extraction to implement the fine crack edge detection, gaining a high-efficiency and high-accuracy performance. This article is categorized under: Technologies > Machine Learning Application Areas > Industry Specific Applications Technologies > Classification","Title: Iteratively Reweighted Linear Least Squares For Frequency Estimation In Unbalanced Three-Phase Power System\nYear: 2019\n\nAbstract: Smart grid has attracted increasing attention in the past decade, and one of its common problems is the variation of the nominal frequency (50 or 60 Hz) introduced by harmonics. In this paper, a batch-mode frequency estimator that can accurately obtain the deviation from the nominal frequency is proposed. The signal model, which includes not only the fundamental frequency but also the harmonics, is first defined, and its characteristic is then studied. Employing the linear prediction (LP) property of the model, the deviated frequency is iteratively updated according to the weighted LP errors, to achieve accurate fundamental frequency estimation. Computer simulations indicate that our proposed method is more accurate and reliable than the conventional estimators in the presence of harmonics and amplitude oscillation.","Title: Secure Analytics And Resilient Inference For The Internet Of Things\nYear: 2019\n\nAbstract: Internet of Things (IoT) applications for Smart Cities, such as systems for traffic control and pollution monitoring, increasingly rely on trustworthy and secure data analytics. Proper countermeasures are needed to ensure that IoT applications function reliably under security threats. This paper studies secure analytics and resilient inference for IoT in the context of recursive parameter estimation. A team of devices makes noisy measurements of an unknown parameter, and an attacker manipulates the measurement data of a subset of the devices. We present a resilient recursive estimation algorithm that processes the measurement streams to recover the value of the parameter, even when a subset of the devices fall under attack. The estimator is guaranteed to be strongly consistent - that is, the estimate converges almost surely to the value of the parameter - as long as less than half of the devices fall under attack. We illustrate the performance of the estimator through numerical examples.","Title: Resilient Distributed Field Estimation\nYear: 2020\n\nAbstract: We study resilient distributed field estimation under measurement attacks. A network of agents or devices measures a large, spatially distributed physical field parameter. An adversary arbitrarily manipulates the measurements of some of the agents. Each agent's goal is to process its measurements and information received from its neighbors to estimate only a few specific components of the field. We present SAFE, the saturating adaptive field estimator, a consensus+innovations distributed field estimator that is resilient to measurement attacks. Under sufficient conditions on the compromised measurement streams, the physical coupling between the field and the agents' measurements, and the connectivity of the cyber communication network, SAFE guarantees that each agent's estimate converges almost surely to the true value of the components of the parameter in which the agent is interested. Finally, we illustrate the performance of SAFE through numerical examples.","Title: Non-Iterative DOA Estimation Using Discrete Fourier Transform Interpolation\nYear: 2019\n\nAbstract: A fast and accurate non-iterative direction-of-arrival (DOA) estimation algorithm for multiple targets in additive white Gaussian noise is devised in this paper. The proposed estimator makes use of the two highest magnitudes discrete Fourier transform (DFT) coefficients of the input data and two of their associated neighboring bins, resulting in a deterministic complexity of O(N (1 + log(N))) with N being the number of sensors. The bias and mean squares error of the DOA estimates are analyzed. The simulation results are presented to validate the correctness of theoretical derivation and demonstrate the superiority of the devised estimator over several conventional DOA estimators.","Title: Natural sd-RCCA Secure Public-key Encryptions from Hybrid Paradigms.\nYear: 2019\n\nAbstract: The existence of natural public-key encryption (PKE) schemes satisfying secretly detectable replayable CCA (sd-RCCA) security is left as open. By introducing probabilistic message authentication codes (MACs) into popular KEM plus DEM paradigms, several instances of such schemes are presented in this paper. It is known that the encrypt-then-authenticate paradigm gives an RCCA secure DEM when the underlying MAC is regular (but not strong) secure, where forgeries for old messages might be possible. By further requiring that the validity of such forgeries can be verified only secretly, sd-RCCA secure DEMs is obtained. Combining such DEMs with CCA secure KEMs gives sd-RCCA secure hybrid PKEs. We first formalize the related notions and this paradigm, and also other variants of KEM plus DEM hybrid paradigm since MACs are commonly used in them. Then we show natural examples of desired probabilistic MACs under the standard DDH assumption, and find appropriate KEMs to match the message space for those MACs and then obtain natural instances of sd-RCCA secure hybrid PKEs.","Title: CFS: A Distributed File System for Large Scale Container Platforms\nYear: 2019\n\nAbstract: We propose CFS, a distributed file system for large scale container platforms. CFS supports both sequential and random file accesses with optimized storage for both large files and small files, and adopts different replication protocols for different write scenarios to improve the replication performance. It employs a metadata subsystem to store and distribute the file metadata across different storage nodes based on the memory usage. This metadata placement strategy avoids the need of data rebalancing during capacity expansion. CFS also provides POSIX-compliant APIs with relaxed semantics and metadata atomicity to improve the system performance. We performed a comprehensive comparison with Ceph, a widely-used distributed file system on container platforms. Our experimental results show that, in testing 7 commonly used metadata operations, CFS gives around 3 times performance boost on average. In addition, CFS exhibits better random-read/write performance in highly concurrent environments with multiple clients and processes.","Title: Resilient Distributed Parameter Estimation with Heterogeneous Data.\nYear: 2019\n\nAbstract: This paper studies resilient distributed estimation under measurement attacks. A set of agents each makes successive local, linear, noisy measurements of an unknown vector field collected in a vector parameter. The local measurement models are heterogeneous across agents and may be locally unobservable for the unknown parameter. An adversary compromises some of the measurement streams and changes their values arbitrarily. The agents’ goal is to cooperate over a peer-to-peer communication network to process their (possibly compromised) local measurements and estimate the value of the unknown vector parameter. We present \n<bold xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">SAGE</bold>\n, the Saturating Adaptive Gain Estimator, a distributed, recursive, consensus + innovations estimator that is resilient to measurement attacks. We demonstrate that, as long as the number of compromised measurement streams is below a particular bound, then, \n<bold xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">SAGE</bold>\n guarantees that all of the agents’ local estimates converge almost surely to the value of the parameter. The resilience of the estimator – i.e., the number of compromised measurement streams it can tolerate – does not depend on the topology of the inter-agent communication network. Finally, we illustrate the performance of \n<bold xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">SAGE</bold>\n through numerical examples.","Title: Acoustic collision detection and localization for robot manipulators\nYear: 2020\n\nAbstract: Collision detection is critical for safe robot operation in the presence of humans. Acoustic information originating from collisions between robots and objects provides opportunities for fast collision detection and localization; however, audio information from microphones on robot manipulators needs to be robustly differentiated from motors and external noise sources. In this paper, we present Panotti, the first system to efficiently detect and localize on-robot collisions using low-cost microphones. We present a novel algorithm that can localize the source of a collision with centimeter level accuracy and is also able to reject false detections using a robust spectral filtering scheme. Our method is scalable, easy to deploy, and enables safe and efficient control for robot manipulator applications. We implement and demonstrate a prototype that consists of 8 miniature microphones on a 7 degree of freedom (DOF) manipulator to validate our design. Extensive experiments show that Panotti realizes near perfect on-robot true positive collision detection rate with almost zero false detections even in high noise environments. In terms of accuracy, it achieves an average localization error of less than 3.8 cm under various experimental settings.","Title: New Health-State Assessment Model Based On Belief Rule Base With Interpretability\nYear: 2021\n\nAbstract: Health-state assessment is the foundation of optimal-maintenance decision-making for complex systems to maintain reliability and safety. Generating the assessment results in a convincing and interpretable way to avoid potential risks is of great importance. Belief rule base (BRB) as an interpretable model performs well in health-state assessment. However, the interpretability of a BRB-based model may be lost during the optimization process, which is expressed mainly as three problems: expert knowledge is not effectively used in the optimization process; the optimized rules of BRB may be in conflict with real systems; and some parameters get over-optimized, which may affect experts' initial judgment. Three concepts - \"searching intensity\", \"interpretability constraint of belief distribution\", and \"rule-activation factor\" - are defined to address these problems. Using these concepts, we propose a new health-state assessment model based on the interpretable BRB and a new optimization method to improve the accuracy and preserve the interpretability of the new model. To demonstrate the effectiveness of the proposed model, we conducted an aero-engine case study.","Title: A Two-Stage Deep Learning Registration Method For Remote Sensing Images Based On Sub-Image Matching\nYear: 2021\n\nAbstract: The registration of multi-temporal remote sensing images with abundant information and complex changes is an important preprocessing step for subsequent applications. This paper presents a novel two-stage deep learning registration method based on sub-image matching. Unlike the conventional registration framework, the proposed network learns the mapping between matched sub-images and the geometric transformation parameters directly. In the first stage, the matching of sub-images (MSI), sub-images cropped from the images are matched through the corresponding heatmaps, which are made of the predicted similarity of each sub-image pairs. The second stage, the estimation of transformation parameters (ETP), a network with weight structure and position embedding estimates the global transformation parameters from the matched pairs. The network can deal with an uncertain number of matched sub-image inputs and reduce the impact of outliers. Furthermore, the sample sharing training strategy and the augmentation based on the bounding rectangle are introduced. We evaluated our method by comparing the conventional and deep learning methods qualitatively and quantitatively on Google Earth, ISPRS, and WHU Building Datasets. The experiments showed that our method obtained the probability of correct keypoints (PCK) of over 99% at alpha = 0.05 (alpha: the normalized distance threshold) and achieved a maximum increase of 16.8% at alpha = 0.01, compared with the latest method. The results demonstrated that our method has good robustness and improved the precision in the registration of optical remote sensing images with great variation.","Title: Multiframe Joint Enhancement for Early Interlaced Videos\nYear: 2022\n\nAbstract: Early interlaced videos usually contain multiple and interlacing and complex compression artifacts, which significantly reduce the visual quality. Although the high-definition reconstruction technology for early videos has made great progress in recent years, related research on deinterlacing is still lacking. Traditional methods mainly focus on simple interlacing mechanism, and cannot deal with the complex artifacts in real-world early videos. Recent interlaced video reconstruction deep deinterlacing models only focus on single frame, while neglecting important temporal information. Therefore, this paper proposes a multiframe deinterlacing network joint enhancement network for early interlaced videos that consists of three modules, i.e., spatial vertical interpolation module, temporal alignment and fusion module, and final refinement module. The proposed method can effectively remove the complex artifacts in early videos by using temporal redundancy of multi-fields. Experimental results demonstrate that the proposed method can recover high quality results for both synthetic dataset and real-world early interlaced videos. At the same time, the method also won the first place in the MSU Deinterlacer Benchmark. The code is available at: https://github.com/anymyb/MFDIN.","Title: Succinct Scriptable NIZK via Trusted Hardware\nYear: 2021\n\nAbstract: Non-interactive zero-knowledge proof or argument (NIZK) systems are widely used in many security sensitive applications to enhance computation integrity, privacy and scalability. In such systems, a prover wants to convince one or more verifiers that the result of a public function is correctly computed without revealing the (potential) private input, such as the witness. In this work, we introduce a new notion, called succinct scriptable NIZK, where the prover and verifier(s) can specify the function (or language instance) to be proven via a script. We formalize this notion is UC framework and provide a generic trusted hardware based solution. We then instantiate our solution in both SGX and Trustzone with Lua script engine. The system can be easily used by typical programmers without any cryptographic background. The benchmark result shows that our solution is better than all the known NIZK proof systems w.r.t. prover's running time (1000 times faster), verifier's running time, and the proof size. Finally, we show how the proposed scriptable succinct NIZK can be readily deployed to solve many wellknown problems in the blockchain context, e.g. verifier's dilemma, fast joining for new players, etc..","Title: Dynamic Median Consensus Over Random Networks.\nYear: 2021\n\nAbstract: This paper studies the problem of finding the median of N distinct numbers distributed across networked agents. Each agent updates its estimate for the median from noisy local observations of one of the N numbers and information from neighbors. We consider an undirected random network that is connected on average, and a noisy observation sequence that has finite variance and almost surely decaying bias. We present a consensus+innovations algorithm with clipped innovations. Under some regularity assumptions on the network and observation model, we show that each agent's local estimate converges to the set of median(s) almost surely at an asymptotic sublinear rate. Numerical experiments demonstrate the effectiveness of the presented algorithm.","Title: Oratosquilla Oratoria-Like Amphibious Robot Based on Dielectric Elastomer\nYear: 2021\n\nAbstract: A key challenge for biologically inspired Oratosquilla oratoria amphibious robots is large deformation and flexibility. We have developed a Squilla like soft robot based on dielectric elastic materials (DE). The robot is driven by high-power dielectric elastomer and uses the principle of friction difference and water resistance difference to realize amphibious multi-mode motion. The robot is 9 cm x 5 cm x 7 cm in length, width and height, and weighs 14 g. The fastest speed on land is 12.5 cm/s, and the fastest speed on water is 2.66 cm/s. The robot has high swimming efficiency and can detect the water surface. The experimental results show that the amphibious soft robot for mantis shrimp has high potential and practicability.","Title: Configuration Selection and Vibration Analysis of Double Layer Suspended Cable-Driven Parallel Robot for Intelligent Storage System\nYear: 2021\n\nAbstract: Warehousing system plays an increasingly important role in the development of industry. However, the traditional warehousing system has the disadvantages of low efficiency, large space occupation and high maintenance difficulty, which has been unable to meet the needs of economic and social development. The demand for high efficiency and high stability intelligent storage system is more and more urgent. With the characteristics of large workspace and strong flexibility, suspended cable-driven parallel robot has great application potential in the field of intelligent storage. In this paper, the foundation of a two-layer suspended cable-driven parallel robot was proposed to meet the requirements of intelligent storage. Based on this foundation, a double layer suspended cable-driven parallel robot was established. The kinematics model of the double layer suspended cable-driven parallel robot was established, and the cable length curve in a motion period was obtained. Based on Hamilton's principle, the vibration model of the double layer suspended cable-driven parallel robot was established. The motion and vibration characteristics of the robot were analyzed in ADAMS, and the vibration law of the system was obtained.","Title: Distraction detection of driver based on EEG signals in a simulated driving with alternative secondary task\nYear: 2021\n\nAbstract: Driving distraction is a main human factor of traffic accidents. Distraction would seriously affect the drivers’ cognitive process, inducing the inability to fully perceive the surrounding environment, make the correct judgments and perform the proper operations in time. It is important to identify the drivers’ attentional state accurately and quickly during the driving process. The objective of t...","Title: The Identification And Analysis Of Gas-Related Volcanic Features Within Chang'E-5 Landing Region\nYear: 2021\n\nAbstract: Chang'e-5 (CE-5) successfully landed on the young basalts area in the northeastern Oceanus Procellarum on 1 December 2020. Recent studies on the CE-5 landing area have shown that the lack of gas-related volcanic morphology indicates that the volatile elements captured in the interior of the Moon within late-stage magma is relatively low. Typical lunar gas-related volcanic features include dark mantle deposits, volcanic pits, irregular mare patches and so on. Based on orbital images, topography, and spectral data obtained from multiple missions restricted by the morphologic and compositional characteristics of typical volcanic explosive features, this study investigated the morphological characteristics of the volcanic features in detail and found that there are three dark mantle deposits (DMDs) near the source area of Rima Mairan that have unusually low albedo and abnormally high titanium and iron content than those of the surrounding material. Combined with M-3 spectral analysis, it is shown that DMDs contain some volcanic glass components, which indicates a gas-rich explosive eruption process. In addition to DMDs, irregular mare patches (IMPs) and a volcanic depression/pit have been recognized in this area, both of which indicate a history of gas-related volcanic eruptions. Based on this study and combined with past studies, we determined the volcanic history in the source area of Rima Mairan, including both effusive and explosive volcanic activities.</p>","Title: Species homology analysis method based on amino acid location and physicochemical properties\nYear: 2021\n\nAbstract: The similarity analysis of protein sequences is a method for analyzing the homology between species. In this paper, we first encode a protein sequence into a 9 dimensional feature-vector consisting of a 20 dimensional content ratio vector, a 20 dimensional positionatio vector of the amino acids, and a 9 dimensional mean-physicochemical properties vector. Using the Euclidean distance to characterize the similarity distance of the protein sequence. We tested our method on two datasets: (1) 9 species ofND5 sequences, (2) 28 species of influenza A virus sequences. As a result, to verify the validity and practicability, we compare the correlation between the corresponding method and ClustalW.","Title: Clustering-Aided Graph Signal Sampling and Reconstruction for Large-Scale Sensor Networks\nYear: 2021\n\nAbstract: In this paper we develop a clustering-aided signal sampling and reconstruction method for data acquisition in large-scale sensor networks. Using the localization feature of a large network, we exploit the vertex-domain locality by the localized operator of each vertex on the graph, and develop a clustering method that sequentially selects cluster heads and their corresponding members by the use of...","Title: Machine Learning based Floor-level Sensor Positioning in Smart Buildings\nYear: 2021\n\nAbstract: With the emergence of new technologies, such as 5G, WiFi6, and NB-IoT, sensors are easier to be deployed in smart buildings than before, and more buildings have being built or transformed into smart buildings. Thus, how to track and locate these devices has become a problem. The traditional sensors positioning is achieved by manually recording the position of the sensor or using RSSI measurement. ...","Title: A semi-supervised learning detection method for vision-based monitoring of construction sites by integrating teacher-student networks and data augmentation\nYear: 2021\n\nAbstract: Recently, deep-learning detection methods have achieved huge success in the vision-based monitoring of construction sites in terms of safety control and productivity analysis. However, deep-learning detection methods require large-scale datasets for training purposes, and such datasets are difficult to develop due to the limited accessibility of construction images and the need for labor-intensive annotations. To address this problem, this research proposes a semi-supervised learning detection method for construction site monitoring based on teacher–student networks and data augmentation. The proposed method requires a limited number of labeled data to achieve high detection performance in construction scenarios. Initially, the proposed method trains the teacher object detector with labeled data following weak data augmentation. Next, the trained teacher object detector generates pseudo-detection results from unlabeled images that have been weakly augmented. Finally, the student object detector is trained with the pseudo-detection results and unlabeled images that have been both weakly and strongly augmented. In our experiments, 10,000 annotated construction images from the Alberta Construction Image Dataset (ACID) have been divided into a training set (70%) and a validation set (30%). The proposed method achieved a 91% mean average precision (mAP) on the validation set while only requiring 30% of the training set. In comparison, the existing supervised learning method ResNet50 Faster R-CNN achieved a mAP of 90.8% when training on the full training set. These experimental results show the potential of the proposed method in terms of reducing the time, effort, and costs spent on developing construction datasets. As such, this research has explored the potential of semi-supervised learning methods and increased the practicality of vision-based monitoring systems in the construction industry.","Title: Dynamic COVID risk assessment accounting for community virus exposure from a spatial-temporal transmission model.\nYear: 2021\n\nAbstract: COVID-19 pandemic has caused unprecedented negative impacts on our society, including further exposing inequity and disparity in public health. To study the impact of socioeconomic factors on COVID transmission, we first propose a spatial-temporal model to examine the socioeconomic heterogeneity and spatial correlation of COVID-19 transmission at the community level. Second, to assess the individual risk of severe COVID-19 outcomes after a positive diagnosis, we propose a dynamic, varying-coefficient model that integrates individual-level risk factors from electronic health records (EHRs) with community-level risk factors. The underlying neighborhood prevalence of infections (both symptomatic and pre-symptomatic) predicted from the previous spatial-temporal model is included in the individual risk assessment so as to better capture the background risk of virus exposure for each individual. We design a weighting scheme to mitigate multiple selection biases inherited in EHRs of COVID patients. We analyze COVID transmission data in New York City (NYC, the epicenter of the first surge in the United States) and EHRs from NYC hospitals, where time-varying effects of community risk factors and significant interactions between individual- and community-level risk factors are detected. By examining the socioeconomic disparity of infection risks and interaction among the risk factors, our methods can assist public health decision-making and facilitate better clinical management of COVID patients.","Title: An IoT based parking recommendation system considering distance and parking lot flow\nYear: 2021\n\nAbstract: The IoT (Internet of Things) technology and applications to facilitate \"smart city\" is developing rapidly. In this paper, we propose a parking recommendation system that confirms with the real situation that can achieve a high successful probability to obtain a free parking space when arriving at the parking lot. In our model, we divide the parking process into two parts, and use queueing theory for estimation. The first part is to estimate the driving travel time consumption of reaching the recommended parking lot after the parking demander's sending the parking request. The time is used in the second part to predict the probability of successfully obtaining a free parking space after the path driving time elapsed. Thereby, the probability of failing to obtaining a free parking space after a long way driving can be reduced. We use the SUMO traffic simulator for verification. The analysis of experiment results show that the performance is satisfactory and efficient than other related or traditional decisionmaking methods.","Title: Development of Nursing Informatics Competencies Evaluation Index System of Clinical Nurses.\nYear: 2021\n\nAbstract: For lack of effective and reliable assessment tools of nursing informatics competencies (NIC), we used literature research method, nominal group technology (NGT) and delphi technique to construct an evaluation index system of NIC for clinical nurses, which can provide reference for establishing a training system of talents of nursing informatics.","Title: Robust Channel Estimation for 5G mm Wave Massive MIMO Relay Communication Systems\nYear: 2021\n\nAbstract: Channel estimation is one of the major challenges for 5th Generation (5G) millimeter-wave (mmWave) massive multiple input multiple output (MIMO) relay communication systems. In this paper, we propose a robust channel estimation scheme for 5G mmWave massive MIMO relay communication systems. The proposed scheme takes advantage of the sparsity of the channel ofmmWave systems to further improve the ac...","Title: A dynamic hybrid trust network-based dual-path feedback consensus model for multi-attribute group decision-making in intuitionistic fuzzy environment\nYear: 2022\n\nAbstract: •A hybrid trust network is first formed and dynamically updated with iterations.•A consensus model with a dual-path feedback mechanism is constructed.•DMs can choose whether to conduct modifications while ensuring consensus efficiency.•Trust network-based modifications are recommended while minimizing adjustment cost.","Title: Two-level differential burn-in policy for spatially heterogeneous defect units in semiconductor manufacturing\nYear: 2021\n\nAbstract: Burn-in (BI) is an effective technique in semiconductor manufacturing to weed out defective devices. BI has been generally conducted on all of packaged devices for the same duration. Realizing that devices in the BI population usually have different reliability at various production levels, this study proposes a new two-level differential BI policy and two BI optimization models to determine the cost-optimal and profit-optimal BI decisions, respectively. The BI tests are conducted at two production levels: wafer-level (WL) and package-level (PL). After a common wafer-level BI for all devices, survival devices are subject to three different decisions: rejection without PLBI, acceptance without PLBI, and test with PLBI. The cost objective function consists of the BI test costs, BI failure costs, and warranty failure cost, while the profit objective function considers the manufacturing costs, BI test costs, warranty failure cost, revenue, and yield loss. Spatially varying yield and probability with reliability defects are computed via spatial regression modeling of clustered defect counts. Two numerical examples are used to illustrate the proposed BI policy and models based on the spatial defects modeling. Analytical results demonstrate that the two-level differential BI policy can be a cost- and profit-effective alternative over the conventional single PLBI policy.","Title: A settlement safety assessment method of liquefied natural gas tank based on belief rule base\nYear: 2021\n\nAbstract: In the settlement safety assessment of liquefied natural gas (LNG) tank, there are some problems, such as lack of high-value samples and uncertainty of parameters. Compared with the traditional settlement assessment method, the belief rule base (BRB) model is an effective safety assessment modeling tool by using qualitative knowledge and quantitative information to solve the lack of high-value samples and describe uncertainties. Therefore, a settlement safety assessment method of LNG tanks based on BRB is proposed in this paper. Firstly, the key factors of assessment method is established and calculated through mechanism analysis and the new Fourier series method. Then, the factor weight is determined by the information entropy method to avoid the inaccurate parameter setting caused by vagueness intrinsic to human knowledge. Finally, a case study in a 160,000 m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n LNG tank shows that it has a good performance in safety assessment.","Title: Siamese Network Object Tracking Algorithm Combining Attention Mechanism and Correlation Filter Theory\nYear: 2022\n\nAbstract: Aiming to solve the problem of tracking drift during movement, which was caused by the lack of discriminability of the feature information and the failure of a fixed template to adapt to the change of object appearance, the paper proposes an object tracking algorithm combining attention mechanism and correlation filter theory based on the framework of full convolutional Siamese neural networks. Firstly, the apparent information is processed by using the attention mechanism thought, where the object and search area features are optimized according to the spatial attention and channel attention module. At the same time, the cross-attention module is introduced to process the template branch and search area branch, respectively, which makes full use of the diversified context information of the search area. Then, the background perception correlation filter model with scale adaptation and learning rate adjustment is adopted into the model construction, using as a layer in the network model to realize the object template update. Finally, the optimal object location is determined according to the confidence map with similarity calculation. Experimental results show that the designed method in the paper can promote the object tracking performance under various challenging environments effectively; the success rate increases by 16.2%, and the accuracy rate increases by 16%.","Title: PO-ELIC: Perception-Oriented Efficient Learned Image Coding\nYear: 2022\n\nAbstract: In the past years, learned image compression (LIC) has achieved remarkable performance. The recent LIC methods outperform VVC in both PSNR and MS-SSIM. However, the low bit-rate reconstructions of LIC suffer from artifacts such as blurring, color drifting and texture missing. Moreover, those varied artifacts make image quality metrics correlate badly with human perceptual quality. In this paper, we propose PO-ELIC, i.e., Perception-Oriented Efficient Learned Image Coding. To be specific, we adapt ELIC, one of the state-of-the-art LIC models, with adversarial training techniques. We apply a mixture of losses including hinge-form adversarial loss, Charbonnier loss, and style loss, to finetune the model towards better perceptual quality. Experimental results demonstrate that our method achieves comparable perceptual quality with HiFiC with much lower bitrate.","Title: Application-oriented Serial Interface Communication Protocols Formal Modeling Method\nYear: 2020\n\nAbstract: In order to solve the formal modeling problem of non-standard application-oriented serial interface communication protocol, this paper analyzes data and data interaction relationships of the protocol, classifies these relationships into self-dependent, split/combination, inquiry and response, state transition, then respectively establishes formal mathematical models for these relationships. Using ...","Title: Influence of trust and risk on peer-to-peer investment willingness: a bidirectional perspective\nYear: 2022\n\nAbstract: Purpose The purpose of this paper is to investigate the influence of trust and perceived risk on investment willingness considering the bidirectional relationship between trust and perceived risk in peer-to-peer (P2P) lending. Design/methodology/approach Data were collected from a leading Chinese P2P platform, PPDAI.com. In total, 328 valid responses were received and analyzed using structural equation modeling (SEM). Findings The results show that the influence of trust on investment willingness is significant, whereas that of perceived risk is insignificant. The results also indicate that platform reputation has a positive effect on trust, and the quality of alternatives is positively associated with perceived risk. In addition, the bidirectional perspective should be preferred to cope with the bidirectional relationship between trust and perceived risk in P2P lending. Originality/value This study extends existing research on the influence of trust and perceived risk on investment willingness from a bidirectional perspective, which has not been addressed in the P2P lending context. In addition, this research enriches the current literature about trust and perceived risk by providing more evidence that the relationship between trust and perceived risk is bidirectional and thus the bidirectional model should be preferred. For practice, the study suggests that managers can earn trust and reduce the perceived risk of lenders by continuously providing high-quality products, services and enhancing platform reputation, ultimately improving their investment willingness.","Title: Finite-time stabilization for delaye d quaternion-value d coupled neural networks with saturated impulse\nYear: 2022\n\nAbstract: In this paper, finite-time stabilization (FTS) issue of delayed quaternion-valued coupled neural networks (DQVCNNs) with saturated impulse is discussed for the first time. Satu-rated impulse, time-varying delay and quaternion are first considered into coupled neural networks (CNNs), which makes the model more complex and realistic. Secondly, a hybrid feedback controller is designed, some conditions are derived to stabilize DQVCNNs with saturated impulse in finite time by the idea of polytopic representation and sector non-linearity model, respectively. Furthermore, this paper shows the settling-time of DQVCNNs with saturated impulse, which discloses it related to both impulse and initial state. Next, this paper also presents several corresponding essential corollaries. Lastly, the feasibility of the derived results is further explained by two examples. (c) 2022 Elsevier Inc. All rights reserved.","Title: What Questions Are You Inclined to Answer? Effects of Hierarchy in Corporate Q&A Communities\nYear: 2022\n\nAbstract: An increasing number of companies have started to implement corporate knowledge-sharing communities. Consistent with the observation in the offline setting, employees are less likely to share knowledge with individuals who have higher job ranks (i.e., higher-ups) in corporate communities such as online wikis and discussion groups. Given the importance of managers' engagements in the community and the needs for knowledge sharing across the hierarchy, we examine whether such observation persists in the corporate question-and-answer (Q&A) community, another popular type of corporate knowledge-sharing community. On the one hand, as in the offline setting and other types of communities, employees can still be reluctant to share knowledge with the higher-ranked individuals in the Q&A community. On the other hand, a Q&A community has some unique attributes that can potentially motivate employees to engage more with the higher-ups. Using a unique data set from a large corporate Q&A community and a potential-dyads approach, we find that a user is inclined to respond to a knowledge seeker whose job rank is higher than (versus lower than or the same as) the user's rank in the corporate Q&A community. We further show the causality of the result with a quasi experiment that leverages the promotions announced in our study period. Because these promotions are based on employees' performances before the existence of the community, the promotion announcements are largely exogenous to our research interest. We also find that knowledge providers exert greater effort when answering questions from the higher-ups. Finally, our analyses show that knowledge providers who post more answers to higher-ranked seekers and who display greater effort in those answers are more likely to get promoted in subsequent years. Given the critical role of knowledge sharing and the increasing prevalence of online communities, our study offers a better understanding of the knowledge-sharing pattern in the corporate Q&A community of the hierarchical organizations and delivers useful managerial implications.","Title: The Analysis of Cones within the Tianwen-1 Landing Area\nYear: 2022\n\nAbstract: On 15 May 2021, the Zhurong rover of China's first Mars mission, Tianwen-1 (TW-1), successfully landed in southern Utopia Planitia on Mars. Various landforms were present in the landing area, and this area recorded a complex geological history. Cones are one of the typical landforms in the landing area and Utopia Planitia, and they have a great significance to the local geological processes due to the diversity of their origins. Using High-Resolution Imaging Camera (HiRIC) images collected by the TW-1 orbiter, we identified a total of 272 well-preserved circular cones in the landing area. Detailed surveys of their spatial distribution, morphological characteristics, and morphometric parameters were conducted. A preliminary analysis of the surface characteristics of these cones also provides additional information to strengthen our understanding of them. The results of the high-resolution topographic analysis show that the cone heights are in the range of 10.5-90.8 m and their basal diameters range from 178.9-1206.6 m. We compared the morphometric parameters of the cones in the landing area with terrestrial and Martian analogous features and found that our measured cones are consistent with the ranges of mud volcanoes and also a small subset of igneous origin cones. However, the result of spatial analysis is more favorable to mud volcanoes, and the lower thermal inertia of the cones in the landing area compared to their surrounding materials is also a typical characteristic of mud volcanoes. Based on current evidence and analysis, we favor interpreting the cones in the TW-1 landing area as mud volcanoes.","Title: Flooding Prognostic in Packed Columns Based on Electrical Capacitance Tomography and Convolution Neural Network\nYear: 2022\n\nAbstract: The flooding of packed columns is accompanied by a steep increase in liquid hold-up and pressure drop, resulting in lower mass transfer efficiency and potential damage to equipment. This study aims to investigate, for the first time, the feasibility of electrical capacitance tomography (ECT) and convolutional neural networks (CNNs) as an intensified alternative to conventional flooding prediction methods. ECT allows variations in the predominant characteristics of flooding events to be investigated in greater detail than in previous research. Combined with CNNs, the ECT sensor enables high accuracy on liquid hold-up calculation and strong robustness against noise-contaminated measurements. In this work, a detailed comparison is made between liquid hold-up results using CNNs and a more conventional ECT method based on the Maxwell equation. Both methods can accurately calculate the liquid hold-up at low gas flow rates. The liquid hold-up predicted according to the Maxwell equation did not match the measured values at high gas flow rates, showing discrepancies of up to 68%. In contrast, CNNs are much superior to the Maxwell equation method at high gas flow rates, giving only a 1% mean of difference from the reference liquid hold-up. ECT supported by CNNs shows great fidelity for noninvasive monitoring of local liquid hold-up, allowing for more accurate, localized prediction of loading point, and flooding point in packed columns.","Title: Developing a professional-practice-model-based nursing organizational informatics competency model\nYear: 2022\n\nAbstract: •Established a scientific nursing organizational informatics competency model.•Nursing organizational informatics competency model is crucial for the healthcare organization.•Providing an action plan to develop organizational nursing informatics competencies.","Title: Research on the Control Strategy of Battery Roller Press Deflection Device by Introducing Genetic Algorithm to Optimize Integral Separation PID\nYear: 2022\n\nAbstract: At the site of continuous rolling of lithium battery electrode, most of its correction units use traditional PID control algorithms, coupled with the complex structure of the rolling equipment and the large number of control system actuators, result in the deviation of the pole piece position being controlled within 10mm only. In order to avoid the undesirable industrial problems caused by untimely correction and insufficient control accuracy, this paper proposes a control strategy for lithium battery roll press deflection device with the introduction of GA(Genetic Algorithm) optimized integral separation PID. For the problems of poor self-adaptive capability of deflection control and interference with equipment and environment during the rolling process. Analyze the causes of runout of the pole piece and the structure of the deflection correction system, establish a mathematical model and an integral separation fuzzy PID controller to realize the deflection control. Optimize the key parameters of the controller using GA to improve the control accuracy and performance of the deflection control. Simulations and experiments show that the deviation control strategy proposed in this paper can reduce the position deviation of the polar strip to within 4mm, which can effectively improve the deviation correction accuracy and the anti-interference capability of equipment operation, and also provide a good solution for the deviation control of other large and complex mechanical equipment.","Title: Long-Term Spatiotemporal Characteristics and Impact Factors of Land Surface Temperature of Inhabited Islands with Different Urbanization Levels\nYear: 2022\n\nAbstract: Surface thermal environment (STE) is closely related to the comfort and health of residents, affecting regional livability, and its spatial and temporal changes are deeply affected by the urbanization process. Considering there is a lack of effective comparative analysis on STE in different urbanized inhabited islands, the special geographical unit and vital human settlement environment, long-term spatiotemporal characteristics and impact factor quantitative analyses were performed in two inhabited islands via the RS and GIS methods. The results suggest that the surface heat amplitude of the highly urbanized Xiamen Island decreases, with the surface heat intensity continuing to increase from 2000 to 2020, while that of the lowly urbanized Kinmen Island is reversed. Although the land surface temperature (LST) of the two inhabited islands shows similar spatial distribution characteristics with evident cold/hot spots, the geographical distribution characteristics of high LST zones are significantly different, and the thermal landscape of Xiamen Island is more fragmented, discrete, and simple in shape, as revealed by the landscape metrics. We demonstrate that the area proportion between cooling land (water body and greenland) and warming land (bare land and impervious surface) is the most influential factor of LST in the two islands while the marine environment is a unique contributor to STE of inhabited islands compared with inland cities, where the seawater around the island can reduce LST over a range of distances, and the influence of elevation on LST is mostly indirect. These results provide a scientific basis and case support for understanding the STE situation of inhabited islands with different urbanization levels."],"string":"[\n \"Title: SLA Decomposition: Translating Service Level Objectives to System Level Thresholds\\nYear: 2007\\n\\nAbstract: In today's complex and highly dynamic computing environments, systems/services have to be constantly adjusted to meet service level agreements (SLAs) and to improve resource utilization, thus reducing operating cost. Traditional design of such systems usually involves domain experts who implicitly translate service level objectives (SLOs) specified in SLAs to system-level thresholds in an ad-hoc manner. In this paper, we present an approach that combines performance modeling with performance profiling to create models that translate SLOs to lower-level resource requirements for each system involved in providing the service. Using these models, the process of creating an efficient design of a system/service can be automated, eliminating the involvement of domain experts. We demonstrate that our approach is practical and that it can be applied to different applications and software architectures. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment the SLAs can be met while improving CPU utilization up to 3 times.\",\n \"Title: Analysis of cell spectral efficiency in 3GPP LTE systems.\\nYear: 2013\\n\\nAbstract: A novel analytical framework is presented to evaluate resource consumption, error ratio and spectral efficiency on PHY, MAC and RLC layer in 3GPP LTE systems. Thereby, various aspects of the different LTE system layers are modeled: On PHY layer, association of user terminal to a radio access point, probabilistic radio channel states, adaptive modulation and coding, overhead in LTE radio frame, turbo coded M-QAM block error rate, and Chase combining are taken into account. On MAC layer, hybrid-ARQ protocol, resource assignment failure, and feedback misdetection are accounted for. On RLC layer, segmentation of a RLC SDU into several RLC PDUs, selective repeat - ARQ protocol, feedback loss, and timer for upcoming feedback to be waited for are considered. With the framework, various performance criteria can be evaluated: Resource consumption, error ratio and spectral efficiency are assessed as CDF for any location in a cell, multi-cell scenario map with expected value for each location, CDF for a cell, and expected value and percentile for a cell.\",\n \"Title: Fine-grain stochastic modelling of dynamic power management policies and analysis of their power - latency tradeoffs\\nYear: 2009\\n\\nAbstract: Dynamic power management (DPM) is one of the main system-level low-power techniques for portable devices. This study presents a fine-grain Markov modelling approach that enables accurate analysis of system power and latency characteristics with full consideration of mode switching overheads in both processor and power controller. The new approach also makes it possible to incorporate latency analy...\",\n \"Title: A fair packet dropping algorithm considering channel condition in diff-serv wireless networks\\nYear: 2004\\n\\nAbstract: Similar to wired networks, appropriate buffer management strategy in wireless networks can manage the buffer efficiently, avoid or relieve congestion, so as to guarantee QoS. Because of unique issues in the wireless channel, strategies in wired networks can not apply directly to wireless network. In this paper, we propose a fair dropping algorithm called DS-CFD (diff-serv supported channel sensitive fair dropping) to decide drop policy in wireless networks when congestion occurs. The algorithm considers both channel condition and fairness so as to achieve tradeoff between throughput and fair services, and we give different level of balance to assured services and best effort services. Another parameter is defined to modify resource allocation between different classes, this parameter is also adaptive with network load. We build a simple model of the algorithm and present simulation results to show the performance improvements.\",\n \"Title: Stochastic analysis of power, latency and the degree of concurrency\\nYear: 2010\\n\\nAbstract: Concurrent processing has become the default mode of operation in on-chip systems. Silicon has become cheap enough for having hardware facilities to support very large scale concurrent processing on chip. As a result the availability and applicability of power is becoming more of a limiting factor than logic. However, the advantage of parallelism in reducing power consumption will soon become unrealistic because of the limited scope of reducing Vdd beyond threshold voltage, leaving the reduction of concurrency (through the partial shut-down of system blocks) as a realistic means of reducing power consumption when needed. A stochastic modelling approach is presented in this paper which can integrate the degree of concurrency as a parameter into power and latency analysis. This will facilitate a system design and management regime where the degree of concurrency is used as a means of control to achieve power and performance goals.\",\n \"Title: Energy-efficient virtual machine scheduling in performance-asymmetric multi-core architectures\\nYear: 2012\\n\\nAbstract: Multi-core architectures with asymmetric core performance have recently shown great promise, because applications with different needs can benefit from either the high performance of a fast core or the high parallelism and power efficiency of a group of slow cores. This performance heterogeneity can be particularly beneficial to applications running in virtual machines (VMs) on virtualized servers, which often have different needs and exhibit different performance and power characteristics. Therefore, scheduling VMs on performance-asymmetric multicore architectures can have a great impact on a system's overall energy efficiency. Unfortunately, existing VM managers, such as Xen, have not taken the heterogeneity into account and thus often result in low energy efficiencies. In this paper, we propose a novel VM scheduling algorithm that exploits core performance heterogeneity to optimize the overall system energy efficiency. We first introduce a metric termed energy-efficiency factor to characterize the power and performance behaviors of the applications hosted by VMs on different cores.We then present a method to dynamically estimate the VM's energy-efficiency factors and then map the VMs to heterogeneous cores, such that the energy efficiency of the entire system is maximized. We implement the proposed algorithm in Xen and evaluate it with standard benchmarks on a real testbed. The experimental results show that our solution improves the system energy efficiency (i.e., performance per watt) by 13.5% on average and up to 55% for some benchmarks, compared to the default Xen scheduler.\",\n \"Title: Ensembl'S 10th Year\\nYear: 2010\\n\\nAbstract: Ensembl (http://www.ensembl.org) integrates genomic information for a comprehensive set of chordate genomes with a particular focus on resources for human, mouse, rat, zebrafish and other high-value sequenced genomes. We provide complete gene annotations for all supported species in addition to specific resources that target genome variation, function and evolution. Ensembl data is accessible in a variety of formats including via our genome browser, API and BioMart. This year marks the tenth anniversary of Ensembl and in that time the project has grown with advances in genome technology. As of release 56 ( September 2009), Ensembl supports 51 species including marmoset, pig, zebra finch, lizard, gorilla and wallaby, which were added in the past year. Major additions and improvements to Ensembl since our previous report include the incorporation of the human GRCh37 assembly, enhanced visualisation and data-mining options for the Ensembl regulatory features and continued development of our software infrastructure.\",\n \"Title: Video Transmission over Ad Hoc Networks Using Multiple Description Coding and Clustering-based Multiple Paths\\nYear: 2007\\n\\nAbstract: Ad hoc networks are characterized with frequent link failures and network topology change. These features result in a great challenge to transmit video over ad hoc networks. We propose a novel scheme for robust video transmission over ad hoc networks. Video stream is coded by using multiple description coding strategy and then a clustering-based multiple paths algorithm is applied for routing over ad hoc networks. The paper describes the general issues of multiple description coding and the principle of clustering-based multiple paths algorithm. Simulation results clearly demonstrate the effectiveness of this scheme for supporting error resilient video transmission over ad hoc networks.\",\n \"Title: SML Model-based Management\\nYear: 2007\\n\\nAbstract: Models enable a clear separation between domain knowledge and application-specific details. In the system management arena, there are multiple implementations of model-based system management solutions, but until now, there was no industry-wide agreement on a common language or paradigm to enable interoperability. A new standard has been proposed to describe IT Services, the service modeling language (\\\"SML\\\"). While SML enables interoperability, it still poses challenges in terms of scalable model stores, model validation, and use. This paper discusses an architecture for SML model management and validation and describe and evaluate a prototype implementation with a use case on system management of PlanetLab.\",\n \"Title: On Modulo Linked Graphs\\nYear: 2009\\n\\nAbstract: A graph G is k -linked if G has at least 2k vertices, and for every sequence x 1 ,x 2 ,...,x k ,y 1 ,y 2 ,...,y k of distinct vertices, G contains k pairwise vertex-disjoint paths P 1 ,P 2 ,...,P k such that P i joins x i and y i for i = 1,2,...,k . We say that G is modulo (m 1 ,m 2 ,...,m k )-linked if G is k -linked and, in addition, for any k -tuple (d 1 ,d 2 ,...,d k ) of natural numbers, the paths P 1 ,P 2 ,...,P k can be chosen such that P i has length d i modulo m i for i = 1,2,...,k . Thomassen [15] showed that if each m i is odd and G has sufficiently high connectivity then G is modulo (m 1 ,m 2 ,...,m k )-linked . In this paper, we will prove that when G is $(92\\\\sum_{i=1}^k m_i-44k)$-connected, where m i is a prime or m i = 1, either G is modulo (2m 1 ,2m 2 ,..., 2m k )-linked or G has a vertex set X of order at most 4k *** 3 such that G *** X is bipartite.\",\n \"Title: Perfecting vectorized mechanical drawings\\nYear: 1996\\n\\nAbstract: This article describes a system which has been developed to convert scanned engineering drawings into a vectorized file. The vectorized file consists of lines, arcs, and circles and generates a description of paper-based engineering drawings. The scanned engineering drawing is initially vectorized by a system called RENDER using line-tracking and curve-fitting techniques. However, the results obtained after the initial vectorization are not adequate. This paper discusses a post-processing system called P-RENDER which has been developed to further refine the vectorized line drawings and to recreate the drawing with the exact numbers of lines and arcs. Dashed entities are also detected and recreated. For large C- or D-size engineering drawings the refinement algorithm also leads to a considerable reduction in the size of the CAD database.\",\n \"Title: Implementing Background Net with Knowware System for Personalized Keyword Support\\nYear: 2011\\n\\nAbstract: This article proposes a novel approach that combines user's instant requirement described in keywords with her or his long-term knowledge background to better serve article selection based on personal preference. The knowledge background is represented as a weighted undirected graph called background net that captures the contextual association of words that appear in the articles recommended by the user through incremental learning. With a background net of user constructed, a keyword from the user is personalized to a fuzzy set that represents contextual association of the given keyword to other words involved in the user's background net. An article evaluation with personal preference can be achieved by evaluating similarity between personalized keyword set based on user's background net and a candidate article. The proposed approach makes it possible to construct a search engine optimizer running on the top of search engines to adjust search results, and offer the potential to be integrated with existing search engine techniques to achieve better performance. The target system of personalized article selection can be automatically constructed using Knowware System which is a development tool of KBS for convenient modeling and component reuse.\",\n \"Title: Device discovery in future service platforms through SIP\\nYear: 2012\\n\\nAbstract: This paper proposes an extension to Session Initiation Protocol (SIP) for contextualized service delivery in a service delivery platform (SDP) that enables device specific multimedia delivery. SIP separates between session establishment and description and is thus, amenable to be extended for advanced implementations which make it an ideal platform for service creation. Device specific multimedia delivery needs rich and flexible device descriptions, and our approach proposes advanced device descriptions through semantic technologies. The proposed SIP extensions have been implemented on a SIP Application Server which functions as SDP in IP Multimedia Subsystem (IMS). The validation of the proposed extensions is shown through an Android SIP client application that acts as a device browser and recommender for different multimedia services to users. An example device user agent (UA) application has also been implemented on a laptop.\",\n \"Title: More DCCA-secure public-key encryptions from KEM + DEM style hybrid paradigms and some observations on the 'inner-outer' structure\\nYear: 2014\\n\\nAbstract: Detectable Chosen Ciphertext Security DCCA security is a weaker notion than CCA security. An 'inner-outer' structure is shown to build a CCA-secure PKE from a DCCA-secure PKE, a 1-bounded CCA-secure PKE, and a CPA-secure PKE. In this paper, we first show passive security for DEMs is sufficient for achieving DCCA-secure hybrid PKEs both for KEM+DEM and Tag-KEM/DEM paradigms. Then two DCCA-secure PKEs constructed from CCA secure KEMs are presented. In addition, a counter example to show that the 1-bounded CCA secure component in the 'inner-outer' structure cannot be weakened to CPA one is given, and some possible methods for constructing CCA-secure PKEs from DCCA-secure KEMs are discussed.\",\n \"Title: Body area network for M-health application: demo abstract.\\nYear: 2011\\n\\nAbstract: Body area network, which has great potential in being the main front-end platform of telemedicine and mobile health systems, is currently being heavily developed to keep pace with the continuously rising demand for personalized healthcare. In our system, an entire body area network solution for M-health, including various of body sensors for collecting physiological signals, a cell phone to facilitate the joint processing of spatially and temporally collected medical data from different parts of the body for resource optimization and systematic health monitoring, a server cluster with great data storage capacity, powerful analysis capabilities to provide data storage, data mining and visualization is presented.\",\n \"Title: A database and API for variation, dense genotyping and resequencing data.\\nYear: 2010\\n\\nAbstract: Advances in sequencing and genotyping technologies are leading to the widespread availability of multi-species variation data, dense genotype data and large-scale resequencing projects. The 1000 Genomes Project and similar efforts in other species are challenging the methods previously used for storage and manipulation of such data necessitating the redesign of existing genome-wide bioinformatics resources.Ensembl has created a database and software library to support data storage, analysis and access to the existing and emerging variation data from large mammalian and vertebrate genomes. These tools scale to thousands of individual genome sequences and are integrated into the Ensembl infrastructure for genome annotation and visualisation. The database and software system is easily expanded to integrate both public and non-public data sources in the context of an Ensembl software installation and is already being used outside of the Ensembl project in a number of database and application environments.Ensembl's powerful, flexible and open source infrastructure for the management of variation, genotyping and resequencing data is freely available at http://www.ensembl.org.\",\n \"Title: A partial binary tree DEA-DA cyclic classification model for decision makers in complex multi-attribute large-group interval-valued intuitionistic fuzzy decision-making problems.\\nYear: 2014\\n\\nAbstract: This paper proposes the idea of combining ''interest groups'' with the practical decision information to classify the decision makers (DMs) in complex multi-attribute large-group decision-making (CMALGDM) problems in interval-valued intuitionistic fuzzy (IVIF) environment. It constructs a partial binary tree DEA-DA cyclic classification model to achieve the multiple groups' classification of DMs. Not only does this method provide references for the classification of DMs when the decision information is known, but it also lays foundations for DMs' effective weight determination and the aggregation of decision information. First, this paper normalizes all of the cost attributes into benefit attributes to avoid the wrong decision result. Second, it employs the C-OWA operator to transform IVIF number (IVIFN) samples into single-valued samples. With respect to this transformation, this paper provides the corresponding BUM functions of DMs according to their risk attitudes; therefore, the preference information of DMs can be more objectively aggregated. Third, this paper adopts the partial binary tree DEA-DA cyclic classification model to present an accurate classification of DMs. Thus, for each interest group, group members with different interest preferences can be distinguished and distributed to the appropriate groups. Finally, to show the feasibility and validity of the model, we give an illustrative example.\",\n \"Title: Parallel logic level simulation of VLSI circuits\\nYear: 1994\\n\\nAbstract: In this paper, we study parallel logic level simulation of combinational VLSI Booleannetworks. The simulator is written in Maisie, a simulation language developed at UCLA. Theunique feature of it is that it allows a simulation model to be executed in either conservative oroptimistic modes with minimal changes to the model. It also supports a number of optimizationsto reduce both checkpointing and blocking overheads for the corresponding simulation protocol.Maisie also supports a variety of ...\",\n \"Title: Tree-ring precipitation records since 1860 at Changling Mountain, China\\nYear: 2005\\n\\nAbstract: Based on analysis of tree-ring data from Changling Mountain at south margin of Tengger Desert, China, the precipitation process since 1860 was reconstructed. Estimated series suggested that south margin of Tengger Desert had underwent two obvious humid periods (1868-1876 and 1932-1939) and two dry periods (1877-1894 and 1924-1932, among which the year 1887 and 1888 were appreciably wet). Power spectrum analyses suggested that the estimated series has significant periodicities of 2.46-2.64a and quasi periodicity of 11.67a. © 2005 IEEE.\",\n \"Title: Automated Availability Management Driven by Business Policies\\nYear: 2007\\n\\nAbstract: Policy-driven service management helps reduce IT management cost and it keeps the service management aligned with business objectives. While most of the previous research focuses on performance/resource managements, little has been researched in the area of availability management driven by business policies. This is a critically important task in enterprise IT, because a single failure in enterprise IT could cause huge business loss. It is still unclear how we can automate the availability management in a highly dynamic and complex system according to business level objectives for performance and risk attitude/preference. As a consequence, users can not manage the availability/performance ratio to match their risk tolerance. In this paper, we propose a policy-driven approach to automate run-time availability management in IT systems, according to high level availability and performance objectives. We further apply von Neumann-Morgenstern utility theory to deal with users' risk attitude policies, an important class of business policies specific for availability management, and the associated preference structures. Based on the proposed approach, we implement an automated decision engine for availability management. The initial evaluation of the solution illustrates the significance of the policy-driven approach and it demonstrates its applicability for availability management in complex IT environments. This way IT users can customize their availability to the risks tolerable by business objectives.\",\n \"Title: CpG-discover: A machine learning approach for CpG islands identification from human DNA sequence\\nYear: 2009\\n\\nAbstract: CpG islands (CGIs) play a fundamental role in genome analysis as genomic markers and tumor markers. Identification of potential CGIs has contributed not only to the prediction of promoters of most house-keeping genes and many tissue-specific genes but also to the understanding of the epigenetic causes of cancer. The most current methods for identifying CGIs suffered from various limitations and involved a lot of human intervention for search purpose. In this paper, we implement a HMM-based CGIs identification system, namely CpG-Discover. Experiments have been conducted on the EMBL human DNA database and in comparison with other widely-used tools. The controlled experimental results indicate that our system is a promising tool and has the capability of locating CGIs accurately. In addition, our system has significant differences from other tools in that it avoids the disadvantages of using sliding windows and it reduces the large amount of human intervention needed to search for or to combine potential CGIs (such as, the thresholds of initial density or distance seed). Therefore, given annotated training data set, our system has the adaptability to find other specific nucleotides sequences in DNA.\",\n \"Title: On the Visualization of Time-Varying Structured Grids Using a 3D Warp Texture\\nYear: 2004\\n\\nAbstract: We present a novel scheme to interactively visualize time-varying scalar fields defined on a structured grid. The underlying approach is to maximize the use of current graphics hardware by using 3D texture mapping. This approach commonly suffers from an expensive voxelization of each time-step as well as from large size of the voxel array approximating each step. Hence, in our scheme, instead of explicitly voxelizing each scalar field, we directly store each time-step as a three dimensional texture in its native form. We create the function that warps a voxel grid into the given structured grid. At rendering time, we reconstruct the function at each pixel using hardware-based trilinear interpolation. The resulting coordinates allow us to compute the scalar value at this pixel using a second texture lookup. For fixed grids, the function remains constant across time-steps and only the scalar field table needs to be re-loaded as a texture. Our new approach achieves excellent performance with relatively low texture memory requirements and low approximation error.\",\n \"Title: A note on the generalization of parameterized inexact Uzawa method for singular saddle point problems.\\nYear: 2014\\n\\nAbstract: Recently, Zhang and Wang studied the generalized parameterized inexact Uzawa methods (GPIU) for solving singular saddle point problems (Zhang and Wang, 2013 [22]). In this note, we continue to discuss the semi-convergence of GPIU for solving singular saddle point problems, and weaken some semi-convergent conditions.\",\n \"Title: Capacity planning and power management to exploit sustainable energy\\nYear: 2010\\n\\nAbstract: This paper describes an approach for designing a power management plan that matches the supply of power with the demand for power in data centers. Power may come from the grid, from local renewable sources, and possibly from energy storage subsystems. The supply of renewable power is often time-varying in a manner that depends on the source that provides the power, the location of power generators, and the weather conditions. The demand for power is mainly determined by the time-varying workloads hosted in the data center and the power management policies implemented by the data center. A case study demonstrates how our approach can be used to design a plan for realistic and complex data center workloads. The study considers a data center's deployment in two geographic locations with different supplies of power. Our approach offers greater precision than other planning methods that do not take into account time-varying power supply and demand and data center power management policies.\",\n \"Title: Renewable and cooling aware workload management for sustainable data centers\\nYear: 2012\\n\\nAbstract: Recently, the demand for data center computing has surged, increasing the total energy footprint of data centers worldwide. Data centers typically comprise three subsystems: IT equipment provides services to customers; power infrastructure supports the IT and cooling equipment; and the cooling infrastructure removes heat generated by these subsystems. This work presents a novel approach to model the energy flows in a data center and optimize its operation. Traditionally, supply-side constraints such as energy or cooling availability were treated independently from IT workload management. This work reduces electricity cost and environmental impact using a holistic approach that integrates renewable supply, dynamic pricing, and cooling supply including chiller and outside air cooling, with IT workload planning to improve the overall sustainability of data center operations. Specifically, we first predict renewable energy as well as IT demand. Then we use these predictions to generate an IT workload management plan that schedules IT workload and allocates IT resources within a data center according to time varying power supply and cooling efficiency. We have implemented and evaluated our approach using traces from real data centers and production systems. The results demonstrate that our approach can reduce both the recurring power costs and the use of non-renewable energy by as much as 60% compared to existing techniques, while still meeting the Service Level Agreements.\",\n \"Title: A systematic and practical approach to generating policies from service level objectives\\nYear: 2009\\n\\nAbstract: In order to manage a service to meet the agreed upon SLA, it is important to design a service of the required capacity and to monitor the service thereafter for violations at runtime. This objective can be achieved by translating SLOs specified in the SLA into lower-level policies that can then be used for design and enforcement purposes. Such design and operational policies are often constraints on thresholds of lower level metrics. In this paper, we propose a systematic and practical approach that combines fine-grained performance modeling with regression analysis to translate service level objectives into design and operational policies for multi-tier applications. We demonstrate that our approach can handle both request-based and session-based workloads and deal with workload changes in terms of both request volume and transaction mix. We validate our approach using both the RUBiS e-commerce benchmark and a trace-driven simulation of a business-critical enterprise application. These results show the effectiveness of our approach.\",\n \"Title: Specification-enhanced policies for automated management of changes in IT systems\\nYear: 2006\\n\\nAbstract: Enterprise and grid computing systems are complex and subject to a broad range of changes such as configuration updates, failures, and performance degradations. These changes affect infrastructure elements such as computation and storage nodes, applications, and system management elements such as monitoring infrastructures. Today's best practices in use by system administrators to manage these changes are manual and ad-hoc. In large complex installations, this would lead to high operational costs, broken closed loop automation, and reduced agility. Providing tools and mechanisms to administrators that automate the reaction to these changes is highly desirable and is an active research area. Policy-based management using Event-Condition-Action (ECA) rules is a well-known approach for such automated change management where management actions are executed when specified event-conditions are observed. In complex systems, the interdependence of components generates multiple events when a single change happens causing multiple rules to be triggered. The order of execution of rule actions determines the system behavior necessitating reasoning about execution order. ECA rules do not contain explicit action specifications needed for reasoning and are therefore unsuited for specifying management rules. In this paper, we propose a specification-enhanced ECA model called Event-Condition-Precondition-Action-Postcondition (ECPAP) for designing adaptation rules. ECPAP rules contain action specifications in first order predicate logic enabling us to develop reasoning algorithms to determine enforcement order of multiple rules. The enforcement order is represented as a Boolean Interpreted Petri Net workflow. We introduce a new notion called enforcement semantics that provides guarantees about rule ordering. We have built an adaptation framework using ECPAP model and have demonstrated it for automated change management of Ganglia and HP OpenView monitoring systems. The evaluation of the framework illustrates the significance of the ECPAP model and demonstrates its applicability for managing complex IT environments.\",\n \"Title: DCCA-Secure Public-Key Encryptions from Hybrid Paradigms\\nYear: 2012\\n\\nAbstract: Detectable Chosen Cipher text Security (DCCA security) is a security notion for Public-Key Encryptions proposed recently in [1]. A DCCA-secure encryption is not necessarily CCA-secure, but dangerous decryption queries can be detected and are not allowed to be requested to the decryption oracle. DCCA-secure schemes may helps in constructing of CCA-secure ones. In this paper, we show there are already DCCA-secure public-key encryptions from popular KEM+DEM style hybrid paradigms, and passive security for DEM is sufficient for achieving DCCA-secure hybrid PKEs both for KEM+DEM and Tag-KEM/DEM paradigms. Furthermore, two DCCA-secure Public-Key schemes constructed from CCA secure KEMs by using hybrid paradigms are presented, which fall outside any of the three cases pointed out in [1].\",\n \"Title: Probabilistic performance modeling of virtualized resource allocation\\nYear: 2010\\n\\nAbstract: Virtualization technologies enable organizations to dynamically flex their IT resources based on workload fluctuations and changing business needs. However, only through a formal understanding of the relationship between application performance and virtualized resource allocation can over-provisioning or over-loading of physical IT resources be avoided. In this paper, we examine the probabilistic relationships between virtualized CPU allocation, CPU contention, and application response time, to enable autonomic controllers to satisfy service level objectives (SLOs) while more effectively utilizing IT resources. We show that with only minimal knowledge of application and system behaviors, our methodology can model the probability distribution of response time with a mean absolute error of less than 6% when compared with the measured response time distribution. We then demonstrate the usefulness of a probabilistic approach with case studies. We apply basic laws of probability to our model to investigate whether and how CPU allocation and contention affect application response time, correcting for their effects on CPU utilization. We find mean absolute differences of 8-10% between the modeled response time distributions of certain allocation states, and a similar difference when we add CPU contention. This methodology is general, and should also be applicable to non-CPU virtualized resources and other performance modeling problems.\",\n \"Title: Digital hardware emulation of universal machine and universal line models for real-time electromagnetic transient simulation\\nYear: 2012\\n\\nAbstract: Real-time electromagnetic transient simulation plays an important role in the planning, design, and operation of power systems. Inclusion of accurate and complicated models, such as the universal machine (UM) model and the universal line model (ULM), requires significant computational resources. This paper proposes a digital hardware emulation of the UM and the ULM for real-time electromagnetic transient simulation. It features accurate floating-point data representation, paralleled implementation, and fully pipelined arithmetic processing. The hardware is based on advanced field-programmable gate array (FPGA) using VHDL. A power system transient case study is simulated in real time to validate the design. On a 130-MHz input clock frequency to the FPGA, the achieved execution times for UM and ULM models are 2.5 μs and 1.42 μs, respectively. The captured real-time oscilloscope results demonstrate high accuracy of the emulator in comparison to the offline simulation of the original system in the EMTP-RV software.\",\n \"Title: Accurate estimation of frequency of a single sinusoid based on downsampling\\nYear: 2012\\n\\nAbstract: A new phase-based approach for frequency estimation of a single cisoid in the presence of additive white noise is proposed in this paper. The main idea is to divide the observed data into a number of segments by downsampling and exploit this new structure for parameter estimation. The maximum likelihood estimator for frequency is then developed, which is shown to be superior to conventional phase-based methods in terms of uniform performance. Computer simulations also illustrate that the mean square frequency error of the proposed scheme can attain Cramér-Rao lower bound for sufficiently high signal-to-noise ratio conditions.\",\n \"Title: A 2.4-Gsample/s DVFS FFT Processor for MIMO OFDM Communication Systems\\nYear: 2008\\n\\nAbstract: This paper presents a new dynamic voltage and frequency scaling (DVFS) FFT processor for MIMO OFDM applications. By the proposed multimode multipath-delay-feedback (MMDF) architecture, our FFT processor can process 1-8-stream 256-point FFTs or a high-speed 256-point FFT in two processing domains at minimum clock frequency for DVFS operations. A parallelized radix-24 FFT algorithm is also employed to save the power consumption and hardware cost of complex multipliers. Furthermore, a novel open-loop voltage detection and scaling (OLVDS) mechanism is proposed for fast and robust voltage management. With these schemes, the proposed FFT processor can operate at adequate voltage/frequency under different configurations to support the power-aware feature. A test chip of the proposed FFT processor has been fabricated using UMC 90 nm single-poly nine-metal CMOS process with a core area of 1.88 times1.88 mm2 . The SQNR performance of this FFT chip is over 35.8 dB for QPSK/16-QAM modulation. Power dissipation of 2.4 Gsample/s 256-point FFT computations is about 119.7 mW at 0.85 V. Depending on the operation mode, power can be saved by 18%-43% with voltage scaling in TT corner.\",\n \"Title: A Novel MAC Protocol for Wireless Ad Hoc Networks with Power Control\\nYear: 2007\\n\\nAbstract: Issues such as the hidden and exposed terminal problems and limited traffic carrying capability still remain unsolved in wireless ad hoc networks. In this paper, we present a novel MAC protocol employing power control. Our design mainly focuses on alleviating the problems of the hidden and exposed terminals and enhancing spatial reuse. We introduce an effective power control scheme to facilitate the power negotiation between the source node and the receiver node. Our protocol can collaborate well with high layer protocols such as AODV in the multi-hop scenarios. We implement our protocol in OPNET environment and study the parameters to optimize its performance. Our preliminary simulation results indicate that, with properly chosen parameters, our protocol works well and achieves considerably high performance in both sparse and dense ad hoc networks.\",\n \"Title: Translating Service Level Objectives to lower level policies for multi-tier services\\nYear: 2008\\n\\nAbstract: Service providers and their customers agree on certain quality of service guarantees through Service Level Agreements (SLA). An SLA contains one or more Service Level Objectives (SLO)s that describe the agreed-upon quality requirements at the service level. Translating these SLOs into lower-level policies that can then be used for design and monitoring purposes is a difficult problem. Usually domain experts are involved in this translation that often necessitates application of domain knowledge to this problem. In this article, we propose an approach that combines performance modeling with regression analysis to solve this problem. We demonstrate that our approach is practical and that it can be applied to different n-tier services. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment, the SLA can be met while improving CPU utilization by up to 3 times.\",\n \"Title: RCCA Security for KEM+DEM Style Hybrid Encryptions.\\nYear: 2012\\n\\nAbstract: RCCA security is a weaker notion than CCA security, and has been proven to be sufficient for several cryptographic tasks. This paper adapts RCCA security to the most popular hybrid paradigms, KEM+DEM and Tag-KEM/DEM. It is open to construct an RCCA-secure scheme more efficient than CCA-secure ones. In the setting of Tag-KEM, we solve this by presenting a natural RCCA-secure RSA-based Tag-KEM scheme, named as RSA-TKEM, which is more efficient than all existing methods for constructing a CCA-secure RSA-based Tag-KEM scheme. Unfortunately, combining our RSA-TKEM with passive secure one-time pad following Tag-KEM/DEM paradigm yields an RCCA-insecure hybrid encryption. This shows passive security of DEM is not sufficient now, and Tag-KEM/DEM looses its advantage over KEM+DEM. In spite of this and for completeness, we show RCCA secure DEMs are still sufficient to achieve RCCA-secure hybrid encryptions by following Tag-KEM/DEM. In addition, we show RCCA-secure KEM is sufficient for achieving CCA-secure hybrid encryptions. This is done by introducing a new hybrid paradigm, named as KEM/Tag-DEM, where the ciphertext of KEM is used as a tag for Tag-DEM scheme rather than reversely in Tag-KEM/DEM, so that the security of KEM can be weakened to RCCA one. Tag-DEMs can be constructed as efficiently as DEMs, so RCCA-secure KEMs more efficient than CCA-secure ones become more appealing. © 2013 Springer-Verlag Berlin Heidelberg.\",\n \"Title: Deriving the consequences of genomic variants with the Ensembl API and SNP Effect Predictor\\nYear: 2010\\n\\nAbstract: Summary: A tool to predict the effect that newly discovered genomic variants have on known transcripts is indispensible in prioritizing and categorizing such variants. In Ensembl, a web-based tool (the SNP Effect Predictor) and API interface can now functionally annotate variants in all Ensembl and Ensembl Genomes supported species. Availability: The Ensembl SNP Effect Predictor can be accessed via the Ensembl website at http://www.ensembl.org/. The Ensembl API (http://www.ensembl.org/info/docs/api/api_installation.html for installation instructions) is open source software. Contact:wm2@ebi.ac.uk; fiona@ebi.ac.uk Supplementary information:Supplementary data are available at Bioinformatics online.\",\n \"Title: A Semi-supervised Method for Classification of Semantic Relation between Nominals\\nYear: 2010\\n\\nAbstract: The task of classifying the semantic relation between two nominals in a sentence is quite challenging due to lack of a large amount of labeled data. Existing models of semantic relation classification were built on either synthetic training data generated from unlabeled data or hand-annotated training data. Meanwhile, previous work showed that the preposition and verb in the sentences indicate important clues to discover the semantic relation between nominals. In this paper we attempt to exploit both labeled and unlabeled data for semantic relation classification under the framework of semi-supervised multi-task learning. Specifically, to improve the generalization performance of a semantic relation classification model, we leverage the information contained in the training signals of multiple related tasks, e.g, prediction of preposition and verb labels. Results on SemEval 2007 task 4 and SemEval 2010 task 8 indicate that semi-supervised multi-task learning method can help semantic relation classification, resulting in comparable or even better performance than the state of art systems in SemEval 2007 task 4.\",\n \"Title: Java mirrors: building blocks for remote interaction\\nYear: 2002\\n\\nAbstract: The Internet has created new opportunities for remote interaction and collaboration. Scientists and engineers working in geographically different locations remotely visualize the results of their large-scale simulations and their models use real-time information captured by remote instruments. The use of mirrors across the Internet and from mobile devices requires novel capabilities from the Java-based JMOSS mirrors which are described in this paper. The Mirror Object Model views all application-level entities as objects with associated methods and state, even when the application is actually written in Fortran or C. The paper presents an interactive design workbench for the Rapid Tooling Testbed (RTTB).\",\n \"Title: Low Bit Rate Compression for SAR Image Based on Blocks Reordering and 3D Wavelet Transform\\nYear: 2011\\n\\nAbstract: Due to that there are a large number of similar characteristics in surface structure of the SAR image, a novel SAR image compression algorithm was proposed based on 3D wavelet transform after block reordering. This proposed algorithm consists of four successive steps: divide the image into sub-blocks with equal size, reorder the sub-blocks according to the similarity measured by weighted Euclidean distance to form 3D array, then 3D wavelet transform and 3D-SPIHT coding are employed for encoding. Experimental results of real SAR images show that the proposed method outperforms the traditional wavelet-based SPIHT in terms of PSNR, especially at the low-bit rate.\",\n \"Title: Decision support for proposal grouping: A hybrid approach using knowledge rule and genetic algorithm\\nYear: 2009\\n\\nAbstract: Proposal grouping is a special procedure in the sponsorship process for research projects. In practice, it is conducted to simplify the following procedure of reviewer assignment. As the proposals grow, this procedure becomes complex. Practical managers spend an increasing amount of time struggling for identifying valid proposals, classifying proposals and partitioning proposals into groups as well as maintaining some control over the quality and composition of the resulting groups. This paper proposes an approach for proposal grouping, in which knowledge rules are designed to deal with proposal identification and proposal classification, and the genetic algorithm is developed to search for the expected groupings. In addition, a corresponding system is designed and developed to support the proposed approach. Compared to the previous manual grouping, the proposed approach significantly reduces the time required for grouping, ensures more diverse group composition, and increases overall grouping quality.\",\n \"Title: Using procedure recovery approach to exchange feature-based data among heterogeneous CAD systems\\nYear: 2009\\n\\nAbstract: Data exchange is one of key issues in collaborative design. The purpose of feature-based data exchange is that the target model is editable after being exchanged. This is the reason why nowadays feature-based data exchanges become the research focus beyond the traditional geometry-based data exchange. This paper presents a two-stage mechanism to recover a complete modeling process of a parametric CAD mode in source systems. Therefore, what we exchange is the procedure of modeling steps. In target systems, we use the exchanged procedure to simulate a real human to reconstruct the parametric CAD mode in any heterogeneous CAD systems. The proposed method has been tested with case studies among typical CAD systems, such as SolidWorks, UG, Pro/E and Catia.\",\n \"Title: Feature identification from vectorized mechanical drawings\\nYear: 1997\\n\\nAbstract: Algorithms to identify 2-D geometric features from the vectorized form of a scanned engineering drawing have been developed. These are based on a pattern matching process where the entities present in the vectorized drawing are checked for specific pattern primitives. The pattern primitives present in an entity are compared with the overall direction of the entity to arrive at the 2-D features that are present. A library of 2-D geometric features has been developed for comparative purposes. For 3-D reconstruction and feature recognition a separation reference point is first found in order to group the entities into their respective views, i.e., top, front, and right side view. This separation reference point is then used to transfer the points belonging to the three orthographic views, expressed in the 2-D coordinate system, to a 3-D coordinate system. The 2-D feature recognition algorithm is applied to each of the three views and the 2-D features recognized in each view are combined using a set of matching primitives and matching rules to arrive at the 3-D features present in the component. 3-D features with linear sweep or rotational sweep and uniform thickness can be recognized.\",\n \"Title: A statistical approach to characterizing the reliability of systems utilizing HBT devices\\nYear: 2005\\n\\nAbstract: This paper describes a statistical approach to simulating the reliability of systems with HBT devices. Compared to the conventional worst-case method, the described approach utilizes statistical reliability information of the HBT individual devices, along with analysis on the critical paths of the system, to provide more accurate and more comprehensive reliability evaluation of the systems utilizing HBT devices.\",\n \"Title: Linked graphs with restricted lengths\\nYear: 2008\\n\\nAbstract: A graph G is k-linked if G has at least 2k vertices, and for every sequence x\\\"1,x\\\"2,...,x\\\"k,y\\\"1,y\\\"2,...,y\\\"k of distinct vertices, G contains k vertex-disjoint paths P\\\"1,P\\\"2,...,P\\\"k such that P\\\"i joins x\\\"i and y\\\"i for i=1,2,...,k. Moreover, the above defined k-linked graph G is modulo(m\\\"1,m\\\"2,...,m\\\"k)-linked if, in addition, for any k-tuple (d\\\"1,d\\\"2,...,d\\\"k) of natural numbers, the paths P\\\"1,P\\\"2,...,P\\\"k can be chosen such that P\\\"i has length d\\\"i modulo m\\\"i for i=1,2,...,k. Thomassen showed that, for each k-tuple (m\\\"1,m\\\"2,...,m\\\"k) of odd positive integers, there exists a natural number f(m\\\"1,m\\\"2,...,m\\\"k) such that every f(m\\\"1,m\\\"2,...,m\\\"k)-connected graph is modulo(m\\\"1,m\\\"2,...,m\\\"k)-linked. For m\\\"1=m\\\"2=...=m\\\"k=2, he showed in another article that there exists a natural number g(2,k) such that every g(2,k)-connected graph G is modulo(2,2,...,2)-linked or there is X@?V(G) such that |X|==2. Our results generalize several known results on parity-linked graphs.\",\n \"Title: A hybrid grouping genetic algorithm for reviewer group construction problem\\nYear: 2011\\n\\nAbstract: It is a common task to construct the reviewer group with diverse background between reviewers. This task is complicated considering the multiple criteria and sizable reviewers and groups. However, it has not been clearly addressed in the current studies. This paper investigates this problem and proposes a solution approach. In our study, this problem is firstly formulated as an integrated model that covers the situations of different group number and group size. Then, considering the computational difficulties of solving this model, the grouping genetic algorithm hybridizing the local neighborhood search heuristic is proposed. In the grouping genetic algorithm, the initialization, crossover and mutation are designed according to our problem's characteristics. Extensive numerical experiments show that the proposed algorithm is computationally efficient. Moreover, the application of the proposed algorithm on a case from NSFC also indicates its effectiveness for practical problems.\",\n \"Title: ECNU: Effective semantic relations classification without complicated features or multiple external corpora\\nYear: 2010\\n\\nAbstract: This paper describes our approach to the automatic identification of semantic relations between nominals in English sentences. The basic idea of our strategy is to develop machine-learning classifiers which: (1) make use of class-independent features and classifier; (2) make use of a simple and effective feature set without high computational cost; (3) make no use of external annotated or unannotated corpus at all. At SemEval 2010 Task 8 our system achieved an F-measure of 75.43% and a accuracy of 70.22%.\",\n \"Title: Opportunistic channels: mobility-aware event delivery\\nYear: 2003\\n\\nAbstract: The delivery of data in pervasive systems has to deal with end host mobility. One problem is how to create appropriate, application-level data provisioning topologies, termed data brokers, to best match underlying network connectivity, end user locations, and the locales of their network access. Another problem is how to balance workloads in such overlay networks, in response to mobility and to changes in available processing and communication resources. This paper improves the performance of data provisioning by dynamically changing broker topologies and end users' assignments to brokers. Specifically, using publish/subscribe as a communication paradigm, a new abstraction, termed an opportunistic event channel, enables dynamic broker creation, deletion, and movement. Experimental and simulation results demonstrate the ability of opportunistic channels to optimize event delivery and processing when end users move across different network access points. The technique is to 'opportunistically' follow network-level handoffs across network access points with application-level handoffs of a user's broker functionality to a new, 'closer' broker. The potential load imbalances across brokers caused by such handoffs are also addressed. Opportunistic channels are realized with the JECho event infrastructure. Performance advantages attained from their use can be substantial, with the cost of sending a message from a publisher to a mobile subscriber improved by up to 50%. Load balancing improves event delivery even for moderate numbers of event subscribers.\",\n \"Title: Maximizing server utilization while meeting critical SLAs via weight-based collocation management\\nYear: 2013\\n\\nAbstract: Servers in most data centers are often underutilized due to concerns about SLA violations that may result from resource contention as server utilization increases. This low utilization means that neither the capital investment in the servers nor the power consumed is being used as effectively as it could be. In this demo, we present a novel method for managing the collocation of critical (e.g., user interactive) and non-critical (e.g., batch) workloads on virtualized multicore servers. Unlike previous cap-based solutions, our approach improves server utilization while meeting the SLAs of critical workloads by prioritizing resource access using Linux cgroups weights. We showcase our work conserving collocation method by utilizing a server to nearly 100% while keeping the performance loss of critical workloads within the specified limits.\",\n \"Title: Effects Of Digital Watermarking On Digital Images\\nYear: 2003\\n\\nAbstract: Digital images are quickly becoming the norm for image capture, storage, or transmission. With physical documents watermarking is used to tag tangible media. Likewise, digital media can also be watermarked. The various reasons for watermarking include: Information hiding, tamper detection, image tagging, and file Access Control. In this paper, we discuss watermarking techniques to 'hide' information in the actual digital image data. However, indiscriminate application of digital watermarking could potentially damage the visual information in a digital image. We analyze three different techniques for watermarking and their affect on the image as we add information. The three types of digital watermarking techniques are investigated in this paper: spatial, frequency, and wavelet domains. Standard digital images are used to investigate, quantitatively and qualitatively, how the image holds the watermark.\",\n \"Title: Construction of a key-dependent message secure symmetric encryption scheme in the ideal cipher model\\nYear: 2014\\n\\nAbstract: Key-dependent message (KDM) security is an important security issue that has attracted much research in recent years. In this paper, we present a new construction of the symmetric encryption scheme in the the ideal cipher model (ICM); we prove that our scheme is KDM secure against active attacks with respect to arbitrary polynomialtime challenge functions. Our main idea is to introduce a universal hash function (UHF) h as a random value for each encryption, and then use s = h(sk) as the key of the ideal cipher F, where sk is the private key of our symmetric encryption scheme. Although many other schemes that are secure against KDM attacks have already been proposed, in both the ideal standard models, the much more significance of our paper is the simplicity in which we implement KDM security against active attacks.\",\n \"Title: A 2D-3D Hybrid Approach to Video Stabilization\\nYear: 2011\\n\\nAbstract: In this paper, we introduce a novel 2D-3D hybrid video stabilization method which combines virtues of 2D and 3D video stabilization methods in one routine. It attempts to achieve high-quality camera motions and to retain full frame coherence in each frame, at while, ensure that local regions undergo a similarity transformation. We solve the stabilization problem by integrating 3D and 2D video stabilization methods into one routine. It smooths camera motions and explicitly employs local motion information which constraints video frames to be temporal coherent, and achieves high-quality video stabilization. Experiments show that our method not only can achieve high-quality camera motion on good 3D reconstructed scene, but also can deal with complicated videos containing near, large moving objects.\",\n \"Title: Object Tracking Using an Improved Kernel Method\\nYear: 2008\\n\\nAbstract: An improved object tracking scheme is presented based on the Kalman filter and mean-shift approach. And this scheme is robust to disturbance and occlusion of both the object and the scene. The object is selected by using FG/BG detection and represented by its center point and probability distribution. The mean-shift approach estimates the object position based on the result of the Kalman filter. A threshold of the Bhattacharyya coefficient is set to judge occlusion and when object being occluded the Kalman filter estimates the object position. Since the proposed scheme combines the space information with probability distribution, it is robust to disturbance and occlusion.\",\n \"Title: Similarity-guided streamline placement with error evaluation.\\nYear: 2007\\n\\nAbstract: Most streamline generation algorithms either provide a particular density of streamlines across the domain or explicitly detect features, such as critical points, and follow customized rules to emphasize those features. However, the former generally includes many redundant streamlines, and the latter requires Boolean decisions on which points are features (and may thus suffer from robustness problems for real-world data). We take a new approach to adaptive streamline placement for steady vector fields in 2D and 3D. We define a metric for local similarity among streamlines and use this metric to grow streamlines from a dense set of candidate seed points. The metric considers not only Euclidean distance, but also a simple statistical measure of shape and directional similarity. Without explicit feature detection, our method produces streamlines that naturally accentuate regions of geometric interest. In conjunction with this method, we also propose a quantitative error metric for evaluating a streamline representation based on how well it preserves the information from the original vector field. This error metric reconstructs a vector field from points on the streamline representation and computes a difference of the reconstruction from the original vector field.\",\n \"Title: Realization of interoperation of geographical information in GeoGlobe Service Platform\\nYear: 2010\\n\\nAbstract: One of the purposes of gathering geographic data is to provide better services for the citizens even in their daily life. As the geographical information resources are heterogeneous, it is important to solve the problem of data interoperation and integration. A GeoGlobe Service Platform (GSP) is designed to provide standard and non-standard spatial information service to all levels of government departments via web. In this paper, we mainly introduce the solution of GIS data sharing in GSP, which is based on the standard web services. Some examples of integrating services developed by using GeoGlobe, SuperMap, MapGIS, and ArcGIS software are given.\",\n \"Title: Approximate Subspace-Based Iterative Adaptive Approach for Fast Two-Dimensional Spectral Estimation\\nYear: 2014\\n\\nAbstract: In this paper, we devise a new approach for fast implementation of two-dimensional (2-D) iterative adaptive approach (IAA) using single or multiple snapshots. Our underlying idea is to apply the subspace methodology in this nonparametric technique by performing the IAA on the dominant singular vectors extracted from the singular value decomposition (SVD) or higher-order SVD of the multidimensional observations. In doing so, 2-D IAA is approximately realized by multiple steps of 1-D IAA, implying that computational attractiveness is achieved particularly for large data size, number of grid points and/or snapshot number. Algorithms based on matrix and tensor operations are developed, and their implementation complexities are analyzed. Computer simulations are also included to compare the proposed approach with the state-of-the-art techniques in terms of resolution probability, spectral estimation performance and computational requirement.\",\n \"Title: QMON: QoS- and Utility-Aware Monitoring in Enterprise Systems\\nYear: 2006\\n\\nAbstract: The scale, reliability and cost requirements of enterprise data centers require automation of center management. Examples include provisioning, scheduling, capacity planning, logging and auditing. A key component of such automation functions is online monitoring. In contrast to monitoring systems designed for human users, a particular concern for online enterprise monitoring is Quality of Service (QoS). Since breaking service level agreements (SLAs) has direct financial and legal implications, enterprise monitoring must be conducted so as to maintain SLAs. This includes the ability to differentiate the QoS of monitoring itself for different classes of users or more generally, for software components subject to different SLAs. Thus, without embedding notions of QoS into the monitoring systems used in next generation data centers, it will not be possible to accomplish the desired automation of their operation. This paper both demonstrates the importance of QoS in monitoring and it presents a QoS-capable monitoring system, termed QMON. QMON supports utility-aware monitoring while also able to differentiate between different classes of monitoring, corresponding to classes of SLAs. The implementation of QMON offers high levels of predictability for service delivery (i.e., predictable performance) and it is dynamically configurable to deal with changes in enterprise needs or variations in services and applications. We demonstrate the importance of QoS in monitoring and the QoS capabilities of QMON in a series of case studies and experiments, using a multi-tier web service benchmark.\",\n \"Title: User Model's Realization of the Personalized Service of Digital Library\\nYear: 2009\\n\\nAbstract: The paper represents a kind of user model truss of digital library's personalized service, detailed discusses some key question including express means of user interest model, build of user interest model and renewal arithmetic, lastly based on the personalized text filtrate arithmetic, get the actual validate result of the digital library. The paper represents the express method of vector user model; adopts SVM (support vector machine) and UC (unsupervised clustering) arithmetic combining to pick-up the user interest; adopts LRU (least recently used) arithmetic to realize the renewal of the user interest. The experiment indicated that this model has these characteristic such as adopting implicit mode to acquire user interest and high hit ratio of user mode renewal.\",\n \"Title: Simulation and analysis of the operating characteristics of MMC based VSC-MTDC system\\nYear: 2013\\n\\nAbstract: With the development of new energy generation, Modular Multilevel Converter (MMC) based HVDC (MMC-HVDC) systems have drawn much attention internationally. This paper focuses on researching the steady and dynamic operating characteristics of an MMC based multi-terminal VSC-HVDC system using the RTDS Simulator. A three-terminal MMC-HVDC system is set up and the operating characteristics of a multi-point DC voltage coordinated control strategy are analyzed. Furthermore, several typical AC and DC contingencies are simulated. The simulation results show that the coordinated control strategy performed well when the MMC-HVDC system operated normally and even when one station was out of service.\",\n \"Title: MSR-Asia at TREC-10 Video Track: Shot Boundary Detection Task\\nYear: 2001\\n\\nAbstract: The video track is added into TREC-10, composed of two tasks, automatic shot boundary detection and video retrieval. In this year, we (MSR-Asia) participated in the video track, focusing on shot boundary detection task. Our work is to find out all of boundaries the shot changes by a fast algorithm based on uncompressed domain. In our algorithm, all of non-cut transitions are considered as gradual transition, including dissolve, fade-in, fade-out, and all kinds of wipes. Experimental results indicate that the accuracy and processing speed of our algorithm are all very satisfactory.\",\n \"Title: Fast algorithm for mining global frequent itemsets based on distributed database\\nYear: 2006\\n\\nAbstract: There were some traditional algorithms for mining global frequent itemsets. Most of them adopted Apriori-like algorithm frameworks. This resulted a lot of candidate itemsets, frequent database scans and heavy communication traffic. To solve these problems, this paper proposes a fast algorithm for mining global frequent itemsets, namely the FMGFI algorithm. It can easily get the global frequency for any itemsets from the local FP-tree and require far less communication traffic by the searching strategies of top-down and bottom-up. It effectively reduces existing problems of most algorithms for mining global frequent itemsets. Theoretical analysis and experimental results suggest that the FMGFI algorithm is fast and effective\",\n \"Title: Active brokers and their runtime deployment in the ECho/JECho distributed event systems\\nYear: 2001\\n\\nAbstract: This paper introduces active brokers and third-party derivation, which is the basic programming construct for run-time remote broker deployment, in the ECho/JECho distributed event systems. We describe its implementation in the JECho system and give examples of using it in ECho/JECho distributed event systems. In particular, we describe the use of third-party derivation in supporting the scalability of content-based event delivery. Specifically, third-party derivation is used both to dynamically construct content-based event distribution trees and to offload potentially expensive client-specific event routing/processing by the run-time creation of remote brokers. Our preliminary benchmark results demonstrate the significant benefits of using third-party derivation.\",\n \"Title: New Application Of Texture Unit Coding, To Mass Classification For Mammograms\\nYear: 2004\\n\\nAbstract: Texture is one of important features of masses in mammograms. A recent texture Unit-based texture spectrum approach, referred to as Texture Unit Coding (TUC) has shown promise in texture classification. This paper presents a new application of the TUC to mass classification in mammograms. The TUC generates a texture spectrum for a texture image that can be used to describe the characteristics of masses. It also develops an information divergence (ID)-based discrimination criterion to measure the discrepancy between two texture spectra, a concept yet to explore in texture analysis. The TUC along with ID are further applied to mass classification in mammograms where the MiniMammographic Database provided by the Mammographic Image Analysis Society (MIAS) is used for experiments.\",\n \"Title: The Design of Virtual Self-timed Block for Activity Communication in SOC\\nYear: 2007\\n\\nAbstract: In this paper we present the architecture for virtual self-timed blocks. Being globally asynchronous locally synchronous (GALS) and lazy reactive processing units, such blocks target multi-processing on-chip systems where power consumption is an important factor. The architecture provides a hardware foundation which transparently supports the systematic organization of application-level activities (processes) and the efficient use of system resources. It further facilitates the seamless integration of IP cores into systems by enhancing the GALS paradigm and protecting clocked IP cores from the temporal nondeterminism in their environments. This work includes the basic design of the virtual self-timed block architecture, Matlab models of the important components involved, and demonstrative analyses in Matlab.\",\n \"Title: Virtual self-timed blocks for systems-on-chip\\nYear: 2006\\n\\nAbstract: Intellectual properties (IP cores) are widely used as pre-designed and reusable units in various system-on-chip (SOC) designs, but their integration has presented difficulties for system designers. In this paper, we propose an approach to better reuse IP cores while maintain energy efficiency for SOC systems. Here we employ a so called self-timed event processor (STEP) to make each IP core into a virtual self-timed block. Much of the IP cores' pre-designed properties can be preserved and the new SOC systems that use virtual self-timed blocks can be more energy efficient. A MATLAB based investigation is carried out on an example STEP processor\",\n \"Title: NvMap: automated analysis of NMR chemical shift perturbation data.\\nYear: 2007\\n\\nAbstract: NMR chemical shift perturbation experiments are widely used to define binding sites in biomolecular complexes. Especially in the case of high throughput screening of ligands, rapid analysis of NMR spectra is essential. NvMap extends NMRViewJ and provides a means for rapid assignments and book-keeping of NMR titration spectra. Our module offers options to analyze multiple titration spectra both separately and sequentially, where the sequential spectra are analyzed either two at a time or all simultaneously. The first option is suitable for slow or intermediate exchange rates between free and bound proteins. The latter option is particularly useful for fast exchange situations and can compensate for the lack of indicators for overlapped peaks. Our module also provides a simple user interface to automate the analysis process from dataset to peak list. We demonstrate the effectiveness of our program using NMR spectra of SUMO in complexes with three different peptides.NvMap is available on the web at http://www.cityofhope.org/Researchers/ChenYuan/NvMap/ Supplemental information: Manual pages and test spectra will be available on the web at the above site.\",\n \"Title: Integrated management of application performance, power and cooling in data centers\\nYear: 2010\\n\\nAbstract: Data centers contain IT, power and cooling infrastructures, each of which is typically managed independently. In this paper, we propose a holistic approach that couples the management of IT, power and cooling infrastructures to improve the efficiency of data center operations. Our approach considers application performance management, dynamic workload migration/consolidation, and power and cooling control to “right-provision” computing, power and cooling resources for a given workload. We have implemented a prototype of this for virtualized environments and conducted experiments in a production data center. Our experimental results demonstrate that the integrated solution is practical and can reduce energy consumption of servers by 35% and cooling by 15%, without degrading application performance.\",\n \"Title: A Generalized Mixed-Radix Algorithm for Memory-Based FFT Processors\\nYear: 2010\\n\\nAbstract: In this brief, a generalized mixed-radix (GMR) algorithm is proposed for memory-based fast Fourier transform (FFT) processors to support prime-sized and traditional 2n -point FFTs simultaneously. It transforms the index to a multidimensional vector for efficient computation. By controlling the index vector to satisfy the ??vector reverse?? behavior, the GMR algorithm can support not only in-place policy for both computation and I/O data for continuous data flow to minimize the memory size but also multibank memory structures to increase the maximum throughput without memory conflict. Finally, a low-complexity implementation of an index vector generator is also proposed for our algorithm.\",\n \"Title: An Indexed-Scaling Pipelined FFT Processor for OFDM-Based WPAN Applications\\nYear: 2008\\n\\nAbstract: In this brief, a high-throughput and low-complexity fast Fourier transform (FFT) processor for wideband orthogonal frequency division multiplexing communication systems is presented. A new indexed-scaling method is proposed to reduce both the critical-path delay and hardware cost by employing shorter wordlength. Together with the mixed-radix multipath delay feedback structure, the proposed FFT processor can achieve very high throughput with low hardware cost. From analysis, it is shown that the proposed indexed-scaling method can save at least 11% memory utilizations compared to other state-of-the-art scaling algorithms. Also, a test chip of a 1.2 Gsample/s 2048-point FFT processor has been designed using UMC 90-nm 1P9M process with a core area of 0.97 mm2. The signal-to-quantization-noise ratio (SQNR) performance of this test chip is over 32.7 dB to support 16-QAM modulation and the power consumption is about 117 mW at 300 MHz. Compared to the fixed-point FFT processors, about 26% area and 28% power can be saved under the same throughput and SQNR specifications.\",\n \"Title: A relational debugging engine for the graphics pipeline\\nYear: 2005\\n\\nAbstract: We present a new, unified approach to debugging graphics software. We propose a representation of all graphics state over the course of program execution as a relational database, and produce a query-based framework for extracting, manipulating, and visualizing data from all stages of the graphics pipeline. Using an SQL-based query language, the programmer can establish functional relationships among all the data, linking OpenGL state to primitives to vertices to fragments to pixels. Based on the Chromium library, our approach requires no modification to or recompilation of the program to be debugged, and forms a superset of many existing techniques for debugging graphics software.\",\n \"Title: Minimizing data center SLA violations and power consumption via hybrid resource provisioning\\nYear: 2011\\n\\nAbstract: This paper presents a novel approach to correctly allocate resources in data centers, such that SLA violations and energy consumption are minimized. Our approach first analyzes historical workload traces to identify long-term patterns that establish a \\\"base\\\" workload. It then employs two techniques to dynamically allocate capacity: predictive provisioning handles the estimated base workload at coarse time scales (e.g., hours or days) and reactive provisioning handles any excess workload at finer time scales (e.g., minutes). The combination of predictive and reactive provisioning achieves a significant improvement in meeting SLAs, conserving energy, and reducing provisioning costs. We implement and evaluate our approach using traces from four production systems. The results show that our approach can provide up to 35% savings in power consumption and reduce SLA violations by as much as 21% compared to existing techniques, while avoiding frequent power cycling of servers.\",\n \"Title: Analysis of Capacity and Error Ratio in 3GPP LTE Systems using Signal Flow Graph Models.\\nYear: 2013\\n\\nAbstract: A novel analytical framework is presented to evaluate capacity and error ratio of different protocol layers in 3GPP LTE systems. Signal flow graphs are used to model various aspects: On PHY layer, association of user terminal to a radio access point, probabilistic radio channel states, adaptive modulation and coding, overhead in LTE radio frame, turbo coded M-QAM block error rate, and Chase combining are taken into account. On MAC layer, hybrid-ARQ, resource assignment failure, and feedback misdetection are accounted for. On RLC layer, segmentation, selective repeat - ARQ, feedback loss, and timer for upcoming feedback are considered.\",\n \"Title: Hardware Emulation Building Blocks for Real-Time Simulation of Large-Scale Power Grids\\nYear: 2014\\n\\nAbstract: This paper proposes digital hardware building block concept for emulating power system networks on field-programmable gate arrays (FPGAs) in real time. Basic hardware emulation building blocks (HEBBs) for machines, transmission lines, nonlinear elements, and loads are presented to demonstrate how real-time simulation can be achieved for realistic power systems. All of the hardware modules were developed using the VHDL language for portability and extensibility. Employing multiple FPGAs, a large-scale power system consisting of 1260 three-phase buses is modeled in detail in real time to show both electromagnetic transients and electromechanical dynamics in the system. The advantage of HEBB-based modeling is that the design and development of new technologies can be accelerated by utilizing massive real-time digital simulators capable of modeling multiscale and multidomain dynamics.\",\n \"Title: Qos Contention Control For Optical Coarse Packet Switched Ip-Over-Wdm Network\\nYear: 2005\\n\\nAbstract: In this paper, we first introduce an Optical Coarse Packet Switching (OCPS) paradigm. In principle, OCPS advocates the enforcement of traffic engineering and control to realize bandwidth-on-demand on sub-wavelength basis while circumventing optical packet switching limitations. Based on OCPS, we have constructed an experimental optical IP-over-WDM network testbed, referred to as OPSINET. In the paper, we present the architectural design of OPSINET and its Hybrid Contention Control (HCC) mechanism aiming to satisfy various classes of loss QoS guarantees. The mechanism preventively adopts appropriate burst sizes for different traffic classes during packet burstification at ingress routers. It also reactively performs prioritized contention resolution at OLSRs in the presence of contention. Experimental results show that HCC invariantly achieves low loss probability as a result of burstification-based traffic shaping. Moreover, it provides satisfied loss guarantees for high-priority classes while incurring minimal loss degradation for lower-priority classes.\",\n \"Title: A Dynamic Pricing Model for E-commerce Based on Data Mining\\nYear: 2009\\n\\nAbstract: In this paper, a dynamic pricing model for e-commerce based on data mining is proposed after the comprehensive analysis of data mining technology applications and e-commerce dynamic pricing strategies. The authors introduce this model into the pricing mechanisms of TaoBao, and discuss the application of the model in C2C and B2C modes, which has great reference value for e-commerce enterprise operation.\",\n \"Title: AppRAISE: application-level performance management in virtualized server environments\\nYear: 2009\\n\\nAbstract: Managing application-level performance for multitier applications in virtualized server environments is challenging because the applications are distributed across multiple virtual machines, and workloads are dynamic in their intensity and transaction mix resulting in time-varying resource demands. In this paper, we present AppRAISE, a system that manages performance of multi-tier applications by dynamically resizing the virtual machines hosting the applications. We extend a traditional queuing model to represent application performance in virtualized server environments, where virtual machine capacity is dynamically tuned. Using this performance model, AppRAISE predicts the performance of the applications due to workload changes, and proactively resizes the virtual machines hosting the applications to meet performance thresholds. By integrating feedforward prediction and feedback reactive control, AppRAISE provides a robust and efficient performance management solution. We tested AppRAISE using Xen virtual machines and the RUBiS benchmark application. Our empirical results show that AppRAISE can effectively allocate CPU resources to application components of multiple applications to meet end-to-end mean response time targets in the presence of variable workloads, while maintaining reasonable trade-offs between application performance, resource efficiency, and transient behavior.\",\n \"Title: Application of hybrid logic in inference of Knowware System\\nYear: 2010\\n\\nAbstract: Handling of uncertainty has been an important topic discussed in the community of intelligent techniques and soft computing. It is necessary to represent human knowledge and modeling its uncertainty when developing an intelligent system. There are various types of uncertainty in the real world, and randomness and fuzziness are of two basic kinds. How to handle these two kinds of uncertainties appearing simultaneously in a system is a main task of intelligent system development. The Knowware System (KWS) has been developed as an intelligent tool for modeling and development of knowledge-based system (KBS). It is to support application developers in constructing customized hybrid intelligent system without the necessity of being familiar with relevant AI techniques. Modeling and processing uncertainty of different types has its significance for further enhancement of KWS mechanism to better support real applications. In this paper, we will present the modeling of KBS with possible uncertainty and the propose handling hybrid uncertainty in inference of KWS, which includes randomness and fuzziness, based on the hybrid logic and chance theory.\",\n \"Title: ℓp-norm based iterative adaptive approach for robust spectral analysis\\nYear: 2014\\n\\nAbstract: Recently, the iterative adaptive approach (IAA) has been shown to be an effective nonparametric methodology for high-resolution spectral analysis. Its main idea is to reformulate the nonlinear frequency estimation problem as a linear model whose parameters are updated iteratively according to weighted least squares. Since the derivation of the IAA is based on @?\\\"2-norm, it cannot work properly in heavy-tailed noise environment. In this paper, a generalized version of IAA is derived to provide accurate spectral estimation in the presence of impulsive noise, which replaces the @?\\\"2-norm by the @?\\\"p-norm where 1\",\n \"Title: A sixth-order subsampling continuous-time bandpass delta-sigma modulator\\nYear: 2005\\n\\nAbstract: A sixth-order bandpass (BP) delta-sigma modulator (ΔΣM) that uses subsampling relative to the radio frequency (RF) or intermediate frequency (IF) of a receiver, while oversampling the signal bandwidth is described in this paper. The continuous-time (CT) filter that works at RF/IF frequency together with the discrete-time (DT) filter operating at lower frequency provide both noise shaping to quantization noise and subsampling noise. The transfer function derivation with finite Q-factor bandpass filter is analyzed. A pulse-shaped DAC is used to reduce the DAC clock jitter and realize the frequency translation. Because the sampling frequency is much lower than the RF/IF frequency, the complexity and power consumption of the subsequent digital signal processing stage is greatly reduced.\",\n \"Title: Fuzzy fair packet dropping algorithm supporting differentiated services\\nYear: 2005\\n\\nAbstract: Random Early Detection (RED) is a kind of buffer management algorithms which is widely used in the current Internet. To improve the adaptability and fairness of RED is one of the main tasks of the active queue management. In this paper, the buffer occupancy of individual flow is replaced by a new introduced variable-Sharing Index to indicate the network resource share among different flows, so as to overcome the limitation of buffer occupancy. The definition of Sharing Index in wireless networks is also extended to make it consider both fairness and system performance (channel condition). Through defining rules of both Sharing Index and queue length, a fuzzy logic based buffer management algorithm named FF-RED is proposed. When calculating packet dropping probability in FF-RED algorithm, the probability will further increase or decrease based on the sharing of network resource (by means of Sharing Index), so it can use the difference between flows to make congestion relief more quickly, and it has better adaptability and fairness. Simulation results show that the system performance is improved through using the proposed algorithm.\",\n \"Title: Random early expiration detection based buffer management algorithm for real-time traffic over wireless networks\\nYear: 2005\\n\\nAbstract: Buffer management algorithms need to decrease queue delay as well as to improve throughput. Because of unique issues in wireless channels, providing delay guarantee in wireless networks is much more complex than that of wired networks. We propose a random early expiration detection based buffer management algorithm for real-time traffic over wireless networks. The main idea is to predict whether new arrival packet can reach the receiver under the limit of maximal delay bound, and random discard the packet based on estimate result, so as to prevent invalid transmission, and at meanwhile to decrease queue delay and to reduce expiration probability of following packets. Considering the characters of wireless link such as variable channel condition and having transmission errors, the algorithm is divided into three stages. We also consider the influence on TCP performance in the design\",\n \"Title: A smart tracking-based jamming scheme for signals with periodic synchronization sequences.\\nYear: 2011\\n\\nAbstract: In this paper, a smart tracking-based jamming scheme is proposed for the signal with synchronization sequences. A different pseudo-random interference sequence, different from the signal's synchronization sequence, is used to track and interfere with the synchronization header in the original signal. With this known pseudo-random synchronization interference sequence, the interference overlapping on the original signal can be nearly cancelled, meanwhile the original signal can be successfully demodulated and decoded at the own receiver without severe interference. However, the other receivers, directly receiving the hybrid signal composed of the original and the pseudo-random interference signals, will fail to recover the original signal without the knowledge of the pseudo-random interference sequence. Compared with traditional full-band full-time noise blanket jamming in communication countermeasures, the advantages of this smart jamming scheme are its low power consumption and up to 100% chance of successful jamming. Simulation results and hardware implementation both show that this scheme can effectively and essentially interfere with the signal at low power consumption. © 2011 IEEE.\",\n \"Title: RCCA security for KEM+DEM style hybrid encryptions and a general hybrid paradigm from RCCA-secure KEMs to CCA-secure encryptions\\nYear: 2014\\n\\nAbstract: AbstractReplayable chosen-ciphertext attack RCCA security is a weaker notion than chosen-ciphertext attack CCA security and has been proven to be sufficient for several cryptographic tasks. However, it is open to construct RCCA-secure schemes more efficient than CCA-secure ones. This paper adapts RCCA security to the most popular hybrid paradigms, KEM+DEM and Tag-KEM/DEM. For KEM+DEM paradigm, we show RCCA security is consistent with the CCA case, just as desired. But for Tag-KEM/DEM paradigm, we find some different status. Natural RCCA-secure Tag-KEM schemes can be easily constructed, which are more efficient than all existing CCA-secure ones. But unfortunately, passive security of DEM is not sufficient to obtain RCCA hybrid encryptions. In spite of this and for completeness, we show RCCA-secure DEMs are still sufficient. On the other hand, for passive secure DEMs, we prove that a stronger notion of RCCA security for Tag-KEM, named as tRCCA security, suffices for RCCA-secure hybrid encryptions. This somewhat suggests that a benign RCCA security for tag-based schemes should be tRCCA security. Finally, to show RCCA-secure KEM is sufficient for achieving CCA-secure hybrid encryptions, we introduce a new hybrid paradigm, named as KEM/Tag-DEM, where the ciphertext of KEM is used as a tag for Tag-DEM scheme rather than reversely in Tag-KEM/DEM, so that the security of KEM can be weakened to RCCA one. KEM/Tag-DEM shows the diversity of hybrid encryptions and has additional practical values. We also show Tag-DEMs can be constructed as efficiently as DEMs. Copyright © 2013 John Wiley & Sons, Ltd.\",\n \"Title: Optimum linear regression in additive Cauchy-Gaussian noise.\\nYear: 2015\\n\\nAbstract: We study the estimation problem of linear regression in the presence of a new impulsive noise model, which is a sum of Cauchy and Gaussian random variables in time domain. The probability density function (PDF) of this mixture noise, referred to as the Voigt profile, is derived from the convolution of the Cauchy and Gaussian PDFs. To determine the linear regression parameters, the maximum likelihood estimator (MLE) is developed first. Since the Voigt profile suffers from a complicated analytical form, an M-estimator with the pseudo-Voigt function is also derived. In our algorithm development, both scenarios of known and unknown density parameters are considered. For the latter case, we estimate the density parameters by utilizing the empirical characteristic function prior to applying the MLE. Simulation results show that the performance of both proposed methods can attain the Cramér–Rao lower bound.\",\n \"Title: A complex multi-attribute large-group decision making method based on the interval-valued intuitionistic fuzzy principal component analysis model\\nYear: 2014\\n\\nAbstract: In the complex multi-attribute large-group decision making (CMALGDM) problems where attribute values are interval-valued intuitionistic fuzzy numbers (IVIFNs), the number of decision attributes is often large and their correlation degrees are high, which increase the difficulty of decision making and thus influence the accuracy of the result. To solve this problem, this paper proposes the interval-valued intuitionistic fuzzy principal component analysis (IVIF-PCA) model. This model represents major information of original attributes, effectively reduces dimensions of attribute space, and synthesizes original attributes into several relatively independent principal components (PCs). The basic thought of this model is as follows: first, we use thoughts of `equivalency' and `order invariance' to transform IVIFN samples into interval number samples; subsequently, we use the `error theory' to replace interval numbers with their middle points, and combine the middle points with the traditional PCA to obtain the PC scores of interval number samples; finally, we adopt the thought of `equivalency' to obtain the PC scores of IVIFN samples. Moreover, based on the IVIF-PCA model, we give a decision making method for the CMALGDM problem. The feasibility and validity of the decision making method is investigated through a numerical example.\",\n \"Title: Dynamic Attack Detection in Cyber-Physical Systems with Side Initial State Information.\\nYear: 2015\\n\\nAbstract: This technical note studies the impact of side initial state information on the detectability of data deception attacks against cyber-physical systems. We assume the attack detector has access to a linear function of the initial system state that cannot be altered by an attacker. First, we provide a necessary and sufficient condition for an attack to be undetectable by any dynamic attack detector under each specific side information pattern. Second, we characterize attacks that can be sustained for arbitrarily long periods without being detected. Third, we define the zero state inducing attack, the only type of attack that remains dynamically undetectable regardless of the side initial state information available to the attack detector. Finally, we design a dynamic attack detector that detects detectable attacks.\",\n \"Title: A two-layer weight determination method for complex multi-attribute large-group decision-making experts in a linguistic environment.\\nYear: 2015\\n\\nAbstract: We propose a two-layer weight determination model in a linguistic environment, when all the clustering results of the experts are known, to objectively obtain expert weights in complex multi-attribute large-group decision-making (CMALGDM) problems. The linguistic information considered in this paper involves both linguistic terms and linguistic intervals. We assume that, for CMALGDM problems, the final expert weights should be determined based on the expert weight in the cluster and on the cluster weights. This is mainly because experts in the same cluster will certainly make varying contributions to the cluster’s overall consensus, and different clusters will also obtain the distinctive “cluster information quality”. Hence, a Minimized Variance Model and an Entropy Weight Model are proposed to determine the expert weights in the cluster and the cluster weights, respectively. We then synthesize these two types of weights into the final objective weights of the CMALGDM experts. The feasibility of the two-layer weight determination model method for the CMALGDM problems is illustrated using a case study of salary reform for professors at a university.\",\n \"Title: A comparative study on multi-regression analysis and BP neural network of PM2.5 index\\nYear: 2014\\n\\nAbstract: The air pollution PM2.5 index is affected by a variety of factors. The research shows that the PM 2.5 index of yesterday, precipitation of yesterday, average temperature, average humidity, precipitation and wind velocity are the main factors which can affect PM2.5 index. The paper utilizes the data of surface meteorological observation and air pollution PM2.5 index of Wuhan City from November 1, 2013 to January 31, 2014. We construct the air pollution PM2.5 index forecasting model according to multiple regression analysis and BP neural network. The empirical study shows that compared to regression prediction model, BP neural network prediction model obtains the nonlinear relation among the prediction factors after training. The predictive model based on BP neural network is of higher predictive precision and better prediction effect which can be used in kinds of prediction research and has good value to popularize.\",\n \"Title: Low peak-to-average ratio OFDM chirp waveform diversity design\\nYear: 2014\\n\\nAbstract: Large time-bandwidth product waveform diversity design is a challenging topic in multiple-input multiple-output radar high-resolution imaging because existing methods usually can generate only two large time-bandwidth product waveforms. This paper proposes a new low peak-to-average ratio (PAR) orthogonal frequency division multiplexing chirp waveform diversity design through randomly subchirp modulation. This method can easily yield over two orthogonal large time-bandwidth product waveforms. More waveforms means that more degrees-of-freedom can be obtained for the system. The waveform performance is evaluated by the ambiguity function. It is shown that the designed waveform has the superiorities of a large time-bandwidth product which means high range resolution and low transmit power are allowed for the system, almost constant time-domain and frequency-domain modulus, low PAR and no range-Doppler coupling response in tracking moving targets.\",\n \"Title: Compressive neighborhood embedding for classification\\nYear: 2014\\n\\nAbstract: Recently, spectral manifold learning algorithms on pattern recognition and machine learning orientation have found wide applications. The common strategy for these algorithms, e.g., Locally Linear Embedding (LLE), facilitates neighborhood relationships which can be constructed by knn or ϵ criterion. This paper presents a simple technique for constructing the nearest neighborhood by combining ℓ2 and ℓ1 norm. The proposed criterion, called Compressive Neighborhood Embedding (CNE), gives rise to a modified spectral manifold learning technique. The validated discriminating power of sparse representation has illuminated in [1], we additionally formulate the semi-supervised learning variation of CNE, SCNE for short, based on the proposed criterion to utilize both labeled and unlabeled data for inference on a graph. Extensive experiments on semi-supervised classification demonstrate the superiority of the proposed algorithm.\",\n \"Title: Density parameter estimation for additive Cauchy-Gaussian mixture\\nYear: 2014\\n\\nAbstract: In this paper, a mixture noise model, which is a sum of symmetric Cauchy and zero-mean Gaussian random variables in time domain, is studied. The Cauchy and Gaussian distributions are characterized by the unknown median γ and variance σ2, respectively. The probability density function (PDF) and characteristic function (CF) of the mixture are also investigated which are calculated by the convolution of the two PDFs, and product of the two CFs, respectively. Due to the complication of the resultant PDF, typical approaches such as maximum likelihood estimator may not be able to estimate γ and σ2 reliably. Based on the resultant CF, we propose to employ the fractional lower-order moment estimator for their computation. Simulation results show the mean square error performance of the proposed method and a comparison with the Cramér-Rao lower bound is also provided.\",\n \"Title: Estimation under additive Cauchy-Gaussian noise using Markov chain Monte Carlo\\nYear: 2014\\n\\nAbstract: In this paper, we consider an impulsive mixture noise process, which commonly comes across in applications such as multiuser radar communications, astrophysical imaging in the microwave range and kick detection in oil drilling. The mixture process is in the time domain, whose probability density function (PDF) corresponds to the convolution of the components' PDFs. In this work, we concentrate on the additive mixture of Gaussian and Cauchy PDFs, the convolution of which leads to a Voigt profile. Due to the complicated nature of the PDF, classical methods such as maximum likelihood estimation may be analytically not tractable; therefore, to estimate signals under such noise, we propose using a Markov chain Monte Carlo method, in particular the Metropolis-Hastings algorithm. For illustration, we study the estimation of a ramp function embedded in the Cauchy-Gauss mixture noise, which is motivated by the kick detection problem in oil drilling. Simulation results demonstrate that the mean square error performance of the proposed algorithm can attain the Cramer-Rao lower bound.\",\n \"Title: ℓ1-norm based nonparametric and semiparametric approaches for robust spectral analysis\\nYear: 2014\\n\\nAbstract: The problem of frequency estimation can be solved by parametric, non-parametric or semi-parametric methods. The representative nonparametric and semiparametric methods, namely, iterative adaptive approach (IAA) and sparse learning via iterative minimization (SLIM) have been recently proposed. Since both of them are not robust to impulsive noise, their extensions, ℓ1-IAA and ℓ1-SLIM are derived to provide accurate spectral estimation in the presence of the heavy-tailed noise in this paper. In our study, the nonlinear frequency estimation problem is mapped to a linear model whose parameters are updated according to the ℓ1-norm and iteratively reweighted least squares. Simulation results are included to demonstrate the outlier resistance performance of the proposed algorithms.\",\n \"Title: Truncated nuclear norm minimization for tensor completion\\nYear: 2014\\n\\nAbstract: In this paper, a tensor n-mode matrix unfolding truncated nuclear norm is proposed, which is extended from the matrix truncated nuclear norm, to tensor completion problem. The alternating direction method of multipliers is utilized to solve this optimization problem. Meanwhile, the original two-step solution of the matrix truncated nuclear norm is reduced to one step. Employing the intermediate results returned by singular value shrinkage operator, rank information of each tensor unfolding matrix is not required and thus the computational complexity of the devised approach is not demanding. Computer simulation results demonstrate the effectiveness of the proposed method.\",\n \"Title: A trust routing protocol based on D-S evidence theory in mobile ad hoc network\\nYear: 2014\\n\\nAbstract: Specific to reliability and security issues in mobile ad hoc network, a trust evaluation model based on Dempster-Shafer evidence theory is proposed. Direct trust is calculated with historical interaction information and indirect trust is obtained from neighbor nodes' commendation evidences. The direct trust and indirect trust are combined according to Dempster rule after being amended with weight so as to obtain nodes' comprehensive trust finally. On this basis, optimize the MPR (Multi-Point Relay) technology in Optimized Link State Routing Protocol, an improved routing protocol TOLSR is proposed to reduce the routing overhead. Simulation results show the model can accurately discover and suppress of selfish nodes, thus can effectively improve the reliability of ad hoc network, which also proves the validity and rationality of the trust evaluation model.\",\n \"Title: Prediction of O-glycosylation sites based on multi-scale composition of amino acids and feature selection.\\nYear: 2015\\n\\nAbstract: Protein glycosylation is one of the most important and complex post-translational modification that provides greater proteomic diversity than any other post-translational modification. Fast and reliable computational methods to identify glycosylation sites are in great demand. Two key issues, feature encoding and feature selection, can critically affect the accuracy of a computational method. We present a new O-glycosylation sites prediction method using only amino acid sequence information. The method includes the following components: (1) on the basis of multi-scale theory, features based on multi-scale composition of amino acids were extracted from the training sequences with identified glycosylation sites; (2) perform a two-stage feature selection to remove features that had adverse effects on the prediction, including a stage one preliminary filtering with Student's t test, and a second stage screening through iterative elimination using novel pairwise comparisons conducted in random subspace using support vector machine. Important features retained are used to build prediction model. The method is evaluated with sequence-based tenfold cross-validation tests on balanced datasets. The results of our experiments show that our method significantly outperforms those reported in the literature in terms of sensitivity, specificity, accuracy, Matthew's correlation coefficient. The prediction accuracy of serine and threonine residues sites reached 95.7 and 92.7 %. The Matthew correlation coefficient of our method for S and T sites is 0.914 and 0.873, respectively. This method can evaluate each feature with the interactions of the rest of the features, which are still included in the model and have the advantage of high efficiency.\",\n \"Title: New method of key‐dependent message security for asymmetric encryption\\nYear: 2015\\n\\nAbstract: Key-dependent message (KDM) security should be considered in the design of security protocols, especially for complicated ones, where the messages related to the secret key might be encrypted. In this paper, we present a new method of constructing a KDM secure asymmetric encryption scheme with the notation of hybrid encryption in the standard model; although the notation of hybrid encryption was thought as no help to get rid of dependencies between messages and the secret key. Our result can also be seen as a partial instantiation for a previously well-known KDM secure asymmetric encryption scheme based on random oracle. As we know, this has never been carried out before. And our result indicates a new cryptographic application for the primitive of lossy trapdoor function. Throughout the paper, our main idea is to archive KDM security by making use of both leakage-resilience and auxiliary-input security properties. Copyright (c) 2014 John Wiley & Sons, Ltd.\",\n \"Title: Variance analysis of unbiased least ℓp-norm estimator in non-Gaussian noise.\\nYear: 2016\\n\\nAbstract: Modeling time and space series in various areas of science and engineering require the values of parameters of interest to be estimated from the observed data. It is desirable to analyze the performance of estimators in an elegant manner without the need for extensive simulations and/or experiments. Among various performance measures, variance is the most basic one for unbiased estimators. In this paper, we focus on the estimator based on the ℓp-norm minimization in the presence of zero-mean symmetric non-Gaussian noise. Four representative noise models, namely, α-stable, generalized Gaussian, Student׳s t and Gaussian mixture processes, are investigated, and the corresponding variance expressions are derived for linear and nonlinear parameter estimation problems at p≥1. The optimal choice of p for different noise environments is studied, where the global optimality and sensitivity analyses are also provided. The developed formulas are verified by computer simulations and are compared with the Cramér-Rao lower bound.\",\n \"Title: Informative gene selection and the direct classification of tumors based on relative simplicity.\\nYear: 2016\\n\\nAbstract: Selecting a parsimonious set of informative genes to build highly generalized performance classifier is the most important task for the analysis of tumor microarray expression data. Many existing gene pair evaluation methods cannot highlight diverse patterns of gene pairs only used one strategy of vertical comparison and horizontal comparison, while individual-gene-ranking method ignores redundancy and synergy among genes.Here we proposed a novel score measure named relative simplicity (RS). We evaluated gene pairs according to integrating vertical comparison with horizontal comparison, finally built RS-based direct classifier (RS-based DC) based on a set of informative genes capable of binary discrimination with a paired votes strategy. Nine multi-class gene expression datasets involving human cancers were used to validate the performance of new method. Compared with the nine reference models, RS-based DC received the highest average independent test accuracy (91.40 %), the best generalization performance and the smallest informative average gene number (20.56). Compared with the four reference feature selection methods, RS also received the highest average test accuracy in three classifiers (Naïve Bayes, k-Nearest Neighbor and Support Vector Machine), and only RS can improve the performance of SVM.Diverse patterns of gene pairs could be highlighted more fully while integrating vertical comparison with horizontal comparison strategy. DC core classifier can effectively control over-fitting. RS-based feature selection method combined with DC classifier can lead to more robust selection of informative genes and classification accuracy.\",\n \"Title: Computed-torque plus robust adaptive compensation control for robot manipulator with structured and unstructured uncertainties.\\nYear: 2016\\n\\nAbstract: A computed-torque plus robust adaptive compensation control scheme (CTRACC) is proposed for trajectory tracking control of a robot manipulator with uncertain dynamics. To eliminate structured and unstructured uncertainties, an adaptive fuzzy control algorithm and a robust H∞ control mode are incorporated in the conventional computed-torque controller. The adaptive fuzzy control algorithm is employ...\",\n \"Title: Performance Characteristics and Temperature Compensation Method of Fluid Property Sensor Based on Tuning-Fork Technology.\\nYear: 2016\\n\\nAbstract: Fluid property sensor (FPS) based on tuning-fork technology is applied to the measurement of the contaminant level of lubricant oil. The measuring principle of FPS sensor is derived and proved together with its resolution. The performance characteristics of the FPS sensor, such as sensitivity coefficient, resolution, and quality factor, are analyzed. A temperature compensation method is proposed to eliminate the temperature-dependence of the measuring parameters, and its validity is investigated by numerical simulation of sensitivity, oscillating frequency, and dielectric constant. The values of purification efficiency obtained using microwave and without microwave are compared experimentally.\",\n \"Title: Deformation Monitoring of Geomechanical Model Test and Its Application in Overall Stability Analysis of a High Arch Dam\\nYear: 2015\\n\\nAbstract: Geomechanical model testing is an important method for studying the overall stability of high arch dams. The main task of a geomechanical model test is deformation monitoring. Currently, many types of deformation instruments are used for deformation monitoring of dam models, which provide valuable information on the deformation characteristics of the prototype dams. However, further investigation is required for assessing the overall stability of high arch dams through analyzing deformation monitoring data. First, a relationship for assessing the stability of dams is established based on the comprehensive model test method. Second, a stability evaluation system is presented based on the deformation monitoring data, together with the relationships between the deformation and overloading coefficient. Finally, the comprehensive model test method is applied to study the overall stability of the Jinping-I high arch dam. A three-dimensional destructive test of the geomechanical model dam is conducted under reinforced foundation conditions. The deformation characteristics and failure mechanisms of the dam abutments and foundation were investigated. The test results indicate that the stability safety factors of the dam abutments and foundation range from 5.2 to 6.0. These research results provide an important scientific insight into the design, construction, and operation stages of this project.\",\n \"Title: Optimal trajectory planning for glass-handing robot based on execution time acceleration and jerk\\nYear: 2016\\n\\nAbstract: AbstractThis study describes a trajectory planning method based on execution time, acceleration, and jerk to ensure that a glass-handing robot runs smoothly at execution time. The minimised objective function consists of the weighted sum of the square of the integral of the execution time, the integral of the acceleration, and the integral of the jerk, all of which are obtained through the weighted coefficient method. At hree-dimensional kinematics model of the glass-handing robot is then established and nonuniform fifth-order B-splines are used to interpolate its path points. The acceleration and jerk are expressed as functions of time through mathematical simulation. Simulation results show that the designed method for robot trajectory planning not only improves the working efficiency of the glass-handing robot but also ensures that it runs smoothly.\",\n \"Title: Some Binomial And Trinomial Differentially 4-Uniform Permutation Polynomials\\nYear: 2015\\n\\nAbstract: Permutation polynomials with low differential uniformity are important candidate functions to design substitution boxes of block ciphers. In this paper, we investigate several classes of differential 4-uniform binomial and trinomial permutation polynomials over the finite field F-2(n) of 2(n) elements.\",\n \"Title: Image denoising by using PDE and GCV in tetrolet transform domain\\nYear: 2016\\n\\nAbstract: The proposed algorithm, which uses partial differential equations (PDE) and generalized cross validation (GCV) theory in the tetrolet transform domain, is used to reduce the noise in an image. Tetrolet transform is applied to decompose the noisy image and GCV theory is used to determine the optimal denoising threshold in the tetrolet transform domain. Then inverse tetrolet transform is used to the modified tetrolet transform coefficients to obtain initial denoising image. PDE model is employed to reduce the block effect which is occurred by only using tetrolet transform to reduce noise, and keeping the edge information. The proposed image denoising algorithm is compared with five similar image denoising algorithms: wavelet transform combined with PDE, contourlet transform combined with PDE, curvelet transform combined PDE, shearlet transform combined with PDE and tetrolet transform combined with PDE, respectively. The experimental results show that comprehensive denoising performance of the proposed algorithm combined with PM1 model (Tetrolet+GCV+PM1) is optimal, especially when PSNR is low. More edges and details can be remained well by the proposed algorithm.\",\n \"Title: Cyber-Physical Systems: Dynamic Sensor Attacks And Strong Observability\\nYear: 2015\\n\\nAbstract: We study cyber-physical systems subject to dynamic sensor attacks, relating them to the system's strong observability. First, we find necessary and sufficient conditions for an attacker to create a dynamically undetectable sensor attack and relate these conditions to properties of the system dynamics eigenvectors. Next, we provide an index that gives the minimum number of sensors that must be attacked in order for an attack to be undetectable. Finally, we illustrate our results with a numerical example on the Quadruple Tank Process.\",\n \"Title: Mosaic: Towards City Scale Sensing with Mobile Sensor Networks\\nYear: 2015\\n\\nAbstract: We introduce Mosaic, a mobile sensor network system for city scale sensing. Currently, we focus on accurate PM2.5 measurements. We design and implement low-cost smart sensors for this purpose. Those sensors are specifically designed for moving vehicles such as buses and taxies. The mobile sensing capability of our system enables a wide coverage of a city with a modest number of sensors. We incorporate a three-layer architecture in Mosaic. Mosaic faces many practical challenges which need to be properly addressed, e.g., reliable node hardware and software design, and accurate PM2.5 measurements. We have built three versions of Mosaic nodes. We present a novel data calibration approach combining traditional Artificial Neural Network (ANN) and Support Vector Machines (SVMs). We launch real-world deployments of Mosaic in two main cities in China -- Hangzhou and Ningbo. Our initial efforts show that Mosaic is a feasible approach for city scale sensing and our system can produce highly accurate PM2.5 measurements.\",\n \"Title: Expanding User Features with Social Relationships in Social Recommender Systems\\nYear: 2013\\n\\nAbstract: Although recommender system has been studied for many years, the research of social recommender system is just beginning. Plenty of information can be used in social networks to improve the performance of recommender system. However, some information is very sparse when used as features. We call this feature sparsity problem. In this paper, we aimed at solving feature sparsity problem. A new strategy was proposed to expand user features by social relationships. Experiments on two real world datasets demonstrated that our method can significantly improve the recommendation performance.\",\n \"Title: Spectral Efficiency Of Lte With Small Cells And Optimum Association Threshold\\nYear: 2014\\n\\nAbstract: A framework is presented for performance analysis of 3GPP LTE with detailed modeling of PHY, MAC and RLC protocol layers taking decode-and-forward relays and small cells into account. CDFs, expected values and percentiles of resource consumption, error ratio and spectral efficiency on various protocol layers are calculated for any grid point and for cells in a multi-cell scenario, respectively. Association of mobile terminals to a radio access point is controlled by an SINR threshold to find out its optimum w.r.t. cell spectral efficiency and cell edge user spectral efficiency.\",\n \"Title: Improving Preemptive Scheduling with Application-Transparent Checkpointing in Shared Clusters.\\nYear: 2015\\n\\nAbstract: Modern data center clusters are shifting from dedicated single framework clusters to shared clusters. In such shared environments, cluster schedulers typically utilize preemption by simply killing jobs in order to achieve resource priority and fairness during peak utilization. This can cause significant resource waste and delay job response time. In this paper, we propose using suspend-resume mechanisms to mitigate the overhead of preemption in cluster scheduling. Instead of killing preempted jobs or tasks, our approach uses a system level, application-transparent checkpointing mechanism to save the progress of jobs for resumption at a later time when resources are available. To reduce the preemption overhead and improve job response times, our approach uses adaptive preemption to dynamically select appropriate preemption mechanisms (e.g., kill vs. suspend, local vs. remote restore) according to the progress of a task and its suspend-resume overhead. By leveraging fast storage technologies, such as non-volatile memory (NVM), our approach can further reduce the preemption penalty to provide better QoS and resource efficiency. We implement the proposed approach and conduct extensive experiments via Google cluster trace-driven simulations and applications on a Hadoop cluster. The results demonstrate that our approach can significantly reduce the resource and power usage and improve application performance over existing approaches. In particular, our implementation on the next generation Hadoop YARN platform achieves up to a 67% reduction in resource wastage, 30% improvement in overall job response time times and 34% reduction in energy consumption over the current YARN scheduler.\",\n \"Title: Joint capacity planning and operational management for sustainable data centers and demand response.\\nYear: 2016\\n\\nAbstract: Reducing costs plays a crucial role in building and operating data centers. Internet service providers such as Facebook and Google spend billions of dollars on capacity expansion and operations of their global data centers. Traditionally, capacity planning for data centers is done separately from operational management, which incurs inefficiency. In fact, operational management has significant impacts on capacity planning. Motivated by this gap, we propose a framework that jointly optimizes both capacity planning and operational management for sustainable data centers and data centers participating in demand response programs. Numerical results based on real-world cases highlight that the proposed framework remarkably reduces up to 50% of total expenditures and 75% of greenhouse gas emissions compared to conventional methods. Additionally, our results show that participations in various demand response programs result in vastly different capacity planning decisions and lead to emission reductions of up to 60%.\",\n \"Title: Mosaic: A Low-Cost Mobile Sensing System For Urban Air Quality Monitoring\\nYear: 2016\\n\\nAbstract: Air quality monitoring has attracted a lot of attention from governments, academia and industry, especially for PM2.5 due to its significant impact on our respiratory systems. In this paper, we present the design, implementation, and evaluation of Mosaic, a low cost urban PM2.5 monitoring system based on mobile sensing. In Mosaic, a small number of air quality monitoring nodes are deployed on city buses to measure air quality. Current low-cost particle sensors based on light-scattering, however, are vulnerable to airflow disturbance on moving vehicles. In order to address this problem, we build our air quality monitoring nodes, Mosaic-Nodes, with a novel constructive airflow-disturbance design based on a carefully tuned airflow structure and a GPS-assisted filtering method. Further, the buses used for system deployment are selected by a novel algorithm which achieves both high coverage and low computation overhead. The collected sensor data is also used to calculate the PM2.5 of locations without direct measurements by an existing inference model. We apply the Mosaic system in a testing urban area which includes more than 70 point-of-interests. Results show that the Mosaic system can accurately obtain the urban air quality with high coverage and low cost.\",\n \"Title: Accelerating graph applications on integrated GPU platforms via instrumentation-driven optimizations.\\nYear: 2016\\n\\nAbstract: Integrated GPU platforms are a cost-effective and energy-efficient option for accelerating data-intensive applications. While these platforms have reduced overhead of offloading computation to the GPU and potential for fine-grained resource scheduling, there remain several open challenges. First, substantial application knowledge is required to leverage GPU acceleration capabilities. Second, static application profiling is inadequate for extracting performance from graph applications that exhibit input-dependent, irregular runtime behaviors. Third, naive scheduling of applications on both CPU and GPU devices may degrade performance due to memory contention.\\n\\nWe describe Luminar, a runtime, profile-guided approach to accelerating applications on integrated GPU platforms. By using efficient dynamic instrumentation, Luminar informs resource scheduling about current workload properties. Luminar engenders up to 40% improvements for irregular, graph-based applications, plus 21-80% improvements in throughput and from 3-60% improvements in energy efficiency when scheduling a mix of applications.\",\n \"Title: Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems.\\nYear: 2018\\n\\nAbstract: This paper studies an attacker against a cyber-physical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker's probability of being detected is related to the non-negative bias induced by his or her attack on the CPS's detection statistic. We formulate a linear quadratic cost...\",\n \"Title: Numerical Investigation on Transverse Maneuverability of a Vectored Underwater Vehicle Without Appendage.\\nYear: 2016\\n\\nAbstract: Vectored underwater vehicles (VUVs) are receiving increasing research attention, in part for their maneuverability. In our work, we apply a novel vectored thruster based on a spherical parallel mechanism to an underwater vehicle. We present and calculate the scaling factor based on the vectored thruster's configuration parameters and set up a six DOF kinematic model. We construct a nonlinear dynamic model of the VUV without appendages using the Newton-Euler method. To demonstrate the VUV's transverse maneuverability, we set up a perturbation model in a complex domain using Laplacian transformation, and propose the stability margin of vectored propulsion as a maneuverability index. Many numerical examples are provided to verify the maneuverability of the VUV.\",\n \"Title: A class of binary cyclic codes with generalized Niho exponents.\\nYear: 2017\\n\\nAbstract: In this paper, a class of binary cyclic codes with three generalized Niho-type nonzeros is introduced. Based on some techniques in solving certain equations over finite fields, the proposed cyclic codes are shown to have six nonzero weights and the weight distribution is also completely determined.\",\n \"Title: Cyber Physical Attacks With Control Objectives And Detection Constraints\\nYear: 2016\\n\\nAbstract: This paper studies attackers with control objectives and explicit detection constraints against cyber-physical systems. The cyber-physical system is equipped with a Kalman filter and an attack detector that uses the innovations process of the Kalman filter. The attacker performs an integrity attack on the actuators and sensors of the system with the aim of moving the system to a target state under the constraint that the probability of him or her being detected is equal to the false alarm probability of the attack detector. We formulate and solve a constrained optimization problem that gives the optimal sequence of attacks and demonstrate our attack strategy in a numerical example.\",\n \"Title: A convergent smoothing algorithm for training max -min fuzzy neural networks.\\nYear: 2017\\n\\nAbstract: Abstract In this paper, a smooth function is constructed to approximate the nonsmooth output of max –min fuzzy neural networks (FNNs) and its approximation is also presented. In place of the output of max –min FNNs by its smoothing approximation function, the error function, defining the discrepancy between the actual outputs and desired outputs of max –min FNNs, becomes a continuously differentiable function. Then, a smoothing gradient decent-based algorithm with Armijo–Goldstein step size rule is formulated to train max –min FNNs. Based on the existing convergent result, the convergence of our proposed algorithm can easily be obtained. Furthermore, the proposed algorithm also provides a feasible procedure to solve fuzzy relational equations with max –min composition. Finally, some numerical examples are implemented to support our results and demonstrate that the proposed smoothing algorithm has better learning performance than other two gradient decent-based algorithms.\",\n \"Title: Kinematics and Singularity Analysis of a Four-Degree-of-Freedom Serial-Parallel Hybrid Manipulator.\\nYear: 2017\\n\\nAbstract: For adapting to the complex working environments of amphibious manipulators, we proposed a serial-parallel hybrid quadruped walking manipulator. We simplified the leg mechanism of the serial-parallel hybrid manipulator as a 2UPU-UPR parallel mechanism, and then analyzed the degree of freedom (DOF) of the parallel mechanism by using the screw theory. The results show that the position of the Y direction and the pose of the Z direction are two independent variables which influence the mechanism movement. We deduced the kinematics inverse solution and the velocity Jacobian matrix of the 2UPU-UPR parallel mechanism. Based on the analysis of the Jacobian matrix, three kinds of kinematic singularities of the 2UPU-UPR parallel mechanism are identified. The results show that the 2UPU-UPR parallel mechanism doesn't have the kinematic inverse singularity, but it has three kinds of kinematic forward singularities and two kinds of combined singularities. Finally, the variation of motorial parameters of this 2UPU-UPR parallel mechanism was discussed by a calculation example.\",\n \"Title: Retinal vessel delineation using a brain-inspired wavelet transform and random forest.\\nYear: 2017\\n\\nAbstract: This paper presents a supervised retinal vessel segmentation by incorporating vessel filtering and wavelet transform features from orientation scores (OSs), and green intensity. Through an anisotropic wavelet-type transform, a 2D image is lifted to a 3D orientation score in the Lie-group domain of positions and orientations R2S1. Elongated structures are disentangled into their corresponding orientation planes and enhanced via multi-orientation vessel filtering. In addition, scale-selective OSs (in the domain of positions, orientations and scales R2S1R+) are obtained by adding a scale adaptation to the wavelet transform. Features are optimally extracted by taking maximum orientation responses at multiple scales, to represent vessels of changing calibers. Finally, we train a Random Forest classifier for vessel segmentation. Extensive validations show that our method achieves a competitive segmentation, and better vessel preservation with less false detections compared with the state-of-the-art methods.\",\n \"Title: SkyLens: Visual Analysis of Skyline on Multi-dimensional Data.\\nYear: 2018\\n\\nAbstract: Skyline queries have wide-ranging applications in fields that involve multi-criteria decision making, including tourism, retail industry, and human resources. By automatically removing incompetent candidates, skyline queries allow users to focus on a subset of superior data items (i.e., the skyline), thus reducing the decision-making overhead. However, users are still required to interpret and com...\",\n \"Title: Concurrent log-structured memory for many-core key-value stores\\nYear: 2017\\n\\nAbstract: AbstractKey-value stores are an important tool in managing and accessing large in-memory data sets. As many applications benefit from having as much of their working state fit into main memory, an important design of the memory management of modern key-value stores is the use of log-structured approaches, enabling efficient use of the memory capacity, by compacting objects to avoid fragmented states.However, with the emergence of thousand-core and peta-byte memory platforms (DRAM or future storage-class memories) log-structured designs struggle to scale, preventing parallel applications from exploiting the full capabilities of the hardware: careful coordination is required for background activities (compacting and organizing memory) to remain asynchronous with respect to the use of the interface, and for insertion operations to avoid contending for centralized resources such as the log head and memory pools.In this work, we present the design of a log-structured key-value store called Nibble that incorporates a multi-head log for supporting concurrent writes, a novel distributed epoch mechanism for scalable memory reclamation, and an optimistic concurrency index. We implement Nibble in the Rust language in ca. 4000 lines of code, and evaluate it across a variety of data-serving workloads on a 240-core cache-coherent server. Our measurements show Nibble scales linearly in uniform YCSB workloads, matching competitive non-log-structured key-value stores for write- dominated traces at 50 million operations per second on 1 TiB-sized working sets. Our memory analysis shows Nibble is efficient, requiring less than 10% additional capacity, whereas memory use by non-log-structured key-value store designs may be as high as 2x.\",\n \"Title: Compressive Sensing Based Interference Cancellation for Ultra Dense Network.\\nYear: 2017\\n\\nAbstract: In this work, we focus on ultra dense network (UDN) which is widely considered as a key component to increase the spectral efficiency for future mobile networks. For the reason that macro and small cells are operating on the same frequencies to increase spectral efficiency, interference from macro-cells and other small-cell users has an impact which can not be neglected. To cope with this challenge, we proposed a minimum mean square error (MMSE) based algorithm to eliminate interference to protect small cell users from macro and small cell interferences in compressive domain. Then Basis Pursuit De-Noising (BPDN) based algorithm is used to reconstruct the desired signal and lower noise. Simulations show that the proposed solution achieves better performance in recovered signal-to-noise ratio (SNR) and complexity reduction.\",\n \"Title: Cyber-Physical Attacks With Control Objectives.\\nYear: 2018\\n\\nAbstract: This paper studies attackers with control objectives against cyber-physical systems (CPSs). The goal of the attacker is to counteract the CPS's controller and move the system to a target state while evading detection. We formulate a cost function that reflects the attacker's goals, and, using dynamic programming, we show that the optimal attack strategy reduces to a linear feedback of the attacker...\",\n \"Title: Calibrating Low-Cost Sensors by a Two-Phase Learning Approach for Urban Air Quality Measurement\\nYear: 2018\\n\\nAbstract: Urban air quality information, e.g., PM2.5 concentration, is of great importance to both the government and society. Recently, there is a growing interest in developing low-cost sensors, installed on moving vehicles, for fine-grained air quality measurement. However, low-cost mobile sensors typically suffer from low accuracy and thus need careful calibration to preserve a high measurement quality. In this paper, we propose a two-phase data calibration method consisting of a linear part and a nonlinear part. We use MLS (multiple least square) to train the linear part, and use RF (random forest) to train the nonlinear part. We propose an automatic feature selection algorithm based on AIC (Akaike information criterion) for the linear model, which helps avoid overfitting due to the inclusion of inappropriate features. We evaluate our method extensively. Results show that our method outperforms existing approaches, achieving an overall accuracy improvement of 16.4% in terms of PM2.5 levels compared with state-of-the-art approach.\",\n \"Title: Resilient Distributed Estimation Through Adversary Detection.\\nYear: 2018\\n\\nAbstract: This paper studies resilient multiagent distributed estimation of an unknown vector parameter when a subset of the agents is adversarial. We present and analyze a flag raising distributed estimator (FRDE) that allows the agents under attack to perform accurate parameter estimation and detect the adversarial agents. The FRDE algorithm is a consensus+innovations estimator in which agents combine est...\",\n \"Title: Novel Smooth Hash Proof Systems Based on Lattices.\\nYear: 2018\\n\\nAbstract: As a basic and important primitive, hash proof system can be used to construct many cryptographic schemes and protocols. Therefore, it is significant to instantiate more efficient hash proof systems from various assumptions. Although there are many hash proof systems based on various classical assumptions, only a handful of efficient hash proof systems are known based on post-quantum assumptions. ...\",\n \"Title: Feedforward fuzzy trajectory compensator with robust adaptive observer at input trajectory level for uncertain multi-link robot manipulators.\\nYear: 2017\\n\\nAbstract: This paper presents an inverse dynamics controller plus feedforward fuzzy trajectory compensator suitable for the trajectory tracking control of uncertain multi-link robot manipulators. To address the issue of unavailable normalization factor, a feedforward fuzzy trajectory compensator is proposed and assembled at the input trajectory level of the inverse dynamics controller rather than at the joint drive torque position. The compensator serving as a low-pass filter is implemented outside the inner control loop by adjusting the desired characteristic trajectory. Due to the nearly unchanged internal control algorithm, the adaptive fuzzy compensator is feasible to implement, and is robust when varying the feedback gain in the inner control loop. Moreover, a robust adaptive fuzzy state observer with loose constraints on the position of uncertain function is designed to assess some unmeasurable state parameters, and a robust term is designed to reduce the influence of the lumped uncertainties. By such design, the observer no longer imposes strict limitations on the position of the nonlinear function and the canonical form of unknown robotic dynamic model. To validate the effectiveness of the proposed controller, simulations and experiments are conducted for a desired characteristic trajectory, and the performance of the proposed controller has been compared with conventional controllers and recently developed controllers to illustrate the usefulness and efficiency of the proposed controller.\",\n \"Title: Tensor Completion via Generalized Tensor Tubal Rank Minimization Using General Unfolding.\\nYear: 2018\\n\\nAbstract: This letter addresses the problem of tensor completion. The properties of the tensor tubal rank (TTR) and tensor Kronecker rank are first discussed, and then a novel generalized tubal Kronecker decomposition together with a new tensor rank referred to as generalized tensor tubal rank (GTTR) are defined. It is shown that the GTTR is suitable for revealing both the Kronecker and tubal structures of ...\",\n \"Title: Point error effect on MDPSK space optical communication system\\nYear: 2017\\n\\nAbstract: Bit error rate (BER) performance is an important indicator to measure the quality of a space optical communication system. Phase modulation technology is an increasingly popular modulation format used in such a system as it provides a better BER performance. M-ary differential phase shift keying (MDPSK) is a new format of phase modulation technologies. In this paper, we discuss a situation that point error is the only mechanical system effect on a MDPSK free space optical communication system. We give the BER expression of a MDPSK system under the effect of point error. Then we numerically analyze several link parameters such as transmission power, transmission aperture, divergence angle and receiver diameter. We concentrate on analyzing how each parameter influences the BER performance of the MDPSK system. These research works are of great value for the study of communication quality in a free space optical communication system with MDPSK modulation format.\",\n \"Title: Anonymous Identity-Based Hash Proof System From Lattices In The Standard Model\\nYear: 2018\\n\\nAbstract: An Identity-Based Hash Proof System (IB-HPS) is a fundamental and important primitive, which is widely adapted to construct a number of cryptographic schemes and protocols, especially for leakage-resilient ones. Therefore it is significant to instantiate IB-HPSs from various assumptions. However, all existing IB-HPSs based on lattices are set only in the random oracle model. Thus, proposing an IB-HPS from lattices in the standard model is an essential and interesting work.In this paper, we introduce a much more compact definition for an anonymous IB-HPS, defining computational indistinguishability of valid/invalid ciphertexts and anonymity of identity simultaneously. Then, through utilizing the technique for delegating a short lattice basis due to Agrawal et al. in CRYPTO 2010 and the property of the smoothing parameter over random lattices, we present a new construction of IB-HPS in the standard model. Furthermore, we show that our new construction is selectively secure and anonymous based on the standard learning with errors (LWE) assumption in the standard model.\",\n \"Title: Central or peripheral? Cognition elaboration cues' effect on users' continuance intention of mobile health applications in the developing markets.\\nYear: 2018\\n\\nAbstract: •This paper aims to explore factors influencing users’ continuance intention of mobile health applications in developing markets.•We proposed the hypotheses and research model based on the elaboration likelihood model and chose Chinese market as the empirical case.•Both perceived usefulness and trust in app promotes users’ continuance intention. Factors of central route and peripheral route positively influence perceived usefulness and users’ trust in app respectively.•Privacy concern enhances the impact of perceived usefulness on continuance intention and strengthens the effect of trust on continuance intention.\",\n \"Title: Automatic Test Transition Paths Generation Approach from EFSM Using State Tree.\\nYear: 2018\\n\\nAbstract: Software testing is important in whole software development process. However, software testing is large in scale, long period, which need to spend a lot of manpower, and financial resources. This paper analyzes the situation of automatic test case generation technology, proposes an approach to decompose the extended finite state machine (EFSM) first, then convert it to an extended finite state tree, and automatically calculate the test state transition paths through the tree, finally selects satisfied paths to test according to the test variable data which determined by test requirements. This approach can automatically calculate as few test transition paths as possible to achieve state coverage and path coverage requirements, the generated continuous state transition paths are beneficial to the comprehensive test of the state transition of EFSM. Compared with other automatic test path generation methods of EFSM, our approach can automatically generate fewer test transition paths from EFSM and reduce the test time.\",\n \"Title: Attack Resilient Distributed Estimation: A Consensus Plus Innovations Approach\\nYear: 2018\\n\\nAbstract: This paper studies fully distributed parameter estimation under sensor attacks. A group of agents make measurements of a bounded parameter and a fraction of the agents' sensor measurements falls under integrity attack. When a sensor is under attack, its measurement can take any value as determined by the attacker. The agents exchange messages over a communication network to ensure that all agents are able to correctly estimate the parameter of interest. This paper presents a consensus+innovations algorithm for attack resilient distributed parameter estimation. The algorithm achieves the same level of resilience as the most resilient centralized estimator if less than half of the agents' sensors are under attack, then all agents correctly estimate the parameter of interest, regardless of the topology of the inter-agent communication network, as long as it is connected. This paper illustrates the performance of the algorithm under adversarial attack through numerical simulations.\",\n \"Title: Robust Frequency Estimation in Symmetric \\\\(\\\\alpha \\\\) -Stable Noise.\\nYear: 2018\\n\\nAbstract: The symmetric (alpha )-stable (S(alpha )S) noise is commonly encountered in a variety of applications such as wireless communications and image processing. In this work, combining the linear prediction property and (ell _p)-norm minimization, a robust frequency estimator is devised for a complex sinusoid in the presence of the S(alpha )S noise. The proposed algorithm, based on the (ell _p)-norm of the preprocessed linear prediction errors, can be regarded as the outlier-resistant version of the generalized weighted linear prediction frequency estimation approach. Computer simulations are conducted to contrast the performance of the proposed algorithm with three conventional frequency estimators. The results indicate that our method is robust to outliers and nearly optimal compared with Cramer–Rao lower bound.\",\n \"Title: Tensor Completion Using Kronecker Rank-1 Tensor Train With Application To Visual Data Inpainting\\nYear: 2018\\n\\nAbstract: The problem of data reconstruction with partly sampled elements under a tensor structure, which is referred to as tensor completion, is addressed in this paper. The properties of the rank-1 tensor train decomposition and the tensor Kronecker decomposition are introduced at first, and then the tensor Kronecker rank as well as Kronecker rank-1 tensor train decomposition are defined. The general tensor completion idea is presented following the criterion of minimizing the number of Kronecker rank-1 tensors, which is relaxed to the thresholding problem and the solution is derived. Furthermore, the number of Kronecker rank-1 tensors that the proposed algorithm can retrieve and its complexity order are analyzed. Computer simulations are carried out on real visual data sets and demonstrate that our method yields a superior performance over the state-of-the-art approaches in terms of recovery accuracy and/or computational complexity.\",\n \"Title: Real-Time FPGA-RTDS Co-Simulator for Power Systems.\\nYear: 2018\\n\\nAbstract: This paper proposes a co-simulation platform using field-programmable gate array (FPGA) and real-time digital simulator (RIDS) for the simulation of large power systems. It combines the advantages of high computational power from FPGA and better modelling flexibility from RIDS together. The FPGA therefore acts as an efficient and economical extension to RIDS especially when simulating large ac systems. One of the significant advantages of the proposed co-simulator is that it avoids the potential interface error existing in the conventional approach of interfacing transient stability program with electromagnetic transient programs. Two key aspects of the proposed co-simulator are discussed: 1) the interface design between FPGA and RIDS and 2) the hardware implementation and expandability of the platform. Two case studies are presented to verify the simulation accuracy and capability of the proposed co-simulator. The first case simulates a two-area four-machine power system with one area simulated in FPGA and the other area in RIDS. Comparisons are made with the case where the complete system is simulated in RIDS. The second case simulates a system of 141 buses in FPGA to demonstrate the simulator's capability in simulating large power systems.\",\n \"Title: Auto scaling virtual machines for web applications with queueing theory\\nYear: 2016\\n\\nAbstract: With the rapid development of cloud computing in recent years, more and more individuals and corporations use cloud computing platform to deploy their web applications, which can significantly minimize their deployment costs. However, it is observed that the number of accesses to some web application often fluctuates over time, resulting in the so-called peak-valley phenomenon: the amount of reserved resources is often proportional to the peak need of physical resources, while most of the time the amount of required resources is far below the peak load and thus physical servers will be idle for most of the time. To solve this problem, we establish a queuing model M/M/C, which represents infinite source and multi-service window. Based on this queueing model, we can accurately predict the arrival time of each customer, which enables us to calculate the minimum amount of resources that meet the resource needs. Then, we use heuristic algorithms and dynamic programming method to design a Virtual Machine (VM) auto-scaling strategies, including horizontal scaling and vertical scaling. With the proposed model and scaling algorithms, we can make web applications not only meet customer needs, but also use the least amount of resources, improving the resource utilization and minimizing deployment costs. With extensive experiments, we show the proposed model and scaling algorithms can greatly improve resource utilization without sacrificing web application performance.\",\n \"Title: Updatable Identity-Based Hash Proof System Based on Lattices and Its Application to Leakage-Resilient Public-Key Encryption Schemes.\\nYear: 2018\\n\\nAbstract: Identity-based hash proof system is a basic and important primitive. It is widely utilized to construct cryptographic schemes and protocols that are secure against key-leakage attacks. In this paper, we introduce the concept of updatable identity-based hash proof system, in which the related master secret key and the identity secret key can be updated securely. Then, we instantiate this primitive based on lattices in the standard model. Moreover, we introduce an application of this new primitive by giving a generic construction of leakage-resilient public-key encryption schemes with anonymity. This construction can be considered as the integration of the bounded-retrieval model and the continual leakage model. Compared with the existing leakage-resilient schemes, our construction not only is more efficient but also can resist much more key leakage.\",\n \"Title: The Design and Implementation of a Real Time Visual Search System on JD E-commerce Platform.\\nYear: 2018\\n\\nAbstract: We present the design and implementation of a visual search system for real time image retrieval on JD.com, the world's third largest and China's largest e-commerce site. We demonstrate that our system can support real time visual search with hundreds of billions of product images at sub-second timescales and handle frequent image updates through distributed hierarchical architecture and efficient indexing methods. We hope that sharing our practice with our real production system will inspire the middleware community's interest and appreciation for building practical large scale systems for emerging applications, such as e-commerce visual search.\",\n \"Title: A High Performance, Scalable DNS Service for Very Large Scale Container Cloud Platforms.\\nYear: 2018\\n\\nAbstract: Containers and microservices are dominating the world of data center and cloud computing. As the scale, dynamism and complexity grow, the performance of the DNS system in container clusters becomes vital. As the world's third and China's largest e-commerce site by revenue, JD.com runs one of the world's largest Kubernetes container clusters in production. It is imperative that the DNS system can handle extremely high traffic. In this paper, we present ContainerDNS, a high performance DNS system for very large scale container clusters with millions of containers. ContainerDNS maximizes DNS system performance and scalability by optimizing DNS packet processing and using efficient memory and cache management.\\n\\nContainerDNS has been deployed in JD's container platform with 30,000 servers and 500,000 containers running tens of thousands of services and applications. It improves the maximum throughput from 130,000 to 9,000,000 QPS, a 67X performance boost comparing to existing DNS systems.\",\n \"Title: Resilient Distributed Estimation: Exponential Convergence Under Sensor Attacks\\nYear: 2018\\n\\nAbstract: This paper studies fully distributed parameter estimation under measurement attacks. A connected network of agents makes measurements of a parameter while an adversary manipulates a subset of the measurements. The goal of the agents is to recover the parameter in the presence of measurement attacks. This paper presents an iterative consensus+innovations algorithm for resilient distributed estimation. The algorithm ensures that all agents correctly recover the parameter of interest, with exponentially fast rate of convergence, so long as less than 3/10 of the agents' measurements are under attack, regardless of the (connected) network topology. We demonstrate the performance of the algorithm through numerical examples.\",\n \"Title: An adaptive fuzzy sliding mode controller for the depth control of an underactuated underwater vehicle\\nYear: 2018\\n\\nAbstract: An adaptive fuzzy sliding mode controller (AFSMC-A control method combining fuzzy control and sliding mode control; it is an intelligent control method for effective control of complex objects in an uncertain environment.) is proposed for depth control of an underactuated underwater vehicle based on the state-dependent Riccati equation. A proportional integral (PI-The integral action makes the output of the controller proportional to the integral of the deviation, so there is no residual at the end of the excess process, but with the integration effect, the stability is reduced.) control unit is integrated into a sliding mode controller (SMC-Essentially a special kind of nonlinear control, and nonlinearity appears as a control discontinuity.) for its control performance improvements and the steady-state error minimization. The issues on undesirable high frequency chattering in the PI plus SMC are addressed by an adaptive algorithm. A fuzzy controller instead of a switching control section of the robust variable structure is used to ensure the robustness of uncertain systems. Simulation results show that the effective depth control can be accomplished in the presence of various uncertainties.\",\n \"Title: V-Fuzz: Vulnerability-Oriented Evolutionary Fuzzing.\\nYear: 2019\\n\\nAbstract: Fuzzing is a technique of finding bugs by executing a software recurrently with a large number of abnormal inputs. Most of the existing fuzzers consider all parts of a software equally, and pay too much attention on how to improve the code coverage. It is inefficient as the vulnerable code only takes a tiny fraction of the entire code. In this paper, we design and implement a vulnerability-oriented evolutionary fuzzing prototype named V-Fuzz, which aims to find bugs efficiently and quickly in a limited time. V-Fuzz consists of two main components: a neural network-based vulnerability prediction model and a vulnerability-oriented evolutionary fuzzer. Given a binary program to V-Fuzz, the vulnerability prediction model will give a prior estimation on which parts of the software are more likely to be vulnerable. Then, the fuzzer leverages an evolutionary algorithm to generate inputs which tend to arrive at the vulnerable locations, guided by the vulnerability prediction result. Experimental results demonstrate that V-Fuzz can find bugs more efficiently than state-of-the-art fuzzers. Moreover, V-Fuzz has discovered 10 CVEs, and 3 of them are newly discovered. We reported the new CVEs, and they have been confirmed and fixed.\",\n \"Title: Double window spectrogram difference method - A blind estimation of frequency-hopping signal for battlefield communication environment.\\nYear: 2018\\n\\nAbstract: In the area of battlefield communication, blindly hopping period and hopping frequency estimation from a series of noisy frequency-hopping (FH) signals is an important research topic. With the use of short-time Fourier transform, an accurate jointly hopping period and hopping frequency estimator, namely, double window spectrogram difference (DWSD), is developed. Simulation results are included to demonstrate the low complexity and superiority of the developed method over several conventional parameter estimators.\",\n \"Title: Multi-Agent based simulation of Elderly Egress Process and Fall Accident in Senior Apartment Buildings.\\nYear: 2018\\n\\nAbstract: A means of egress from buildings is a critical aspect of building design and an important part of building fire regulations. However, elderly evacuees are often overlooked, being regarded as part of the average population, thereby ignoring the limitations elderly people may have. The computational egress model is a useful tool to evaluate postulated \\\"what-if\\\" scenarios, aiming to predict building egress performance under these designated scenarios. This paper first applies Multi-agent Based Simulation (MABS) supported by NetLogo to simulate the evacuation scenarios where evacuees are all elderly people, then statistical analysis is utilized to interpret results, and comparative analysis is conducted to offer some suggestions for egress design and crowd management.\",\n \"Title: Gait Planning and Simulation Analysis of a New Amphibious Quadruped Robots.\\nYear: 2018\\n\\nAbstract: In order to allow quadruped robots to adapt to the complex working environment in the field of fisheries and aquaculture, a new type of quadruped robot with linear and rotary driving is proposed, and the kinematic inverse solution of the leg of the quadruped robot is deduced. For achieving quadruped robot smooth walking, the straight gait of the quadruped robot is planned according to the stability margin principle of motion, so that the stability margin of the machine is 20 mm when three legs supporting it. The planning gait is simulated by ADAMS software, the kinematics and dynamics analysis of the four main driving mechanisms of the robot leg were carried out, and the feasibility of using the STEP5 driving function to execute the planning gait in the quadruped robot was verified. The theoretical and simulation curve analysis results show that, the quadruped robot according to the planned gait can complete the cycle and have a stable walking. The results of this study can provide a reference for the practical application of the new amphibious quadruped robot in the fields of complex and uneven ground in the field of fisheries and aquaculture to realize exploration, fishing and transportation.\",\n \"Title: Start-Up Demonstration Tests With the Intent of Equipment Classification for Balanced Systems\\nYear: 2019\\n\\nAbstract: A start-up demonstration test is a mechanism that is often applied to determine the acceptability of equipment. Two new start-up demonstration tests are derived and demonstrated with the intent of equipment classification based on the testing results. The two new tests are called the CSTSCFTF_AMGC and CS\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">(1)</sup>\\nCS\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">(1)(2)</sup>\\nTF\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">(1)(2)</sup>\\nTF\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">(2)</sup>\\n_AMGC start-up demonstration tests. By using the finite Markov chain imbedding approach, several probabilistic indexes are presented for the new start-up demonstration tests based on the assumption that the tests are independent and identically distributed cases. Two types of optimization models are formulated and solved for the new start-up demonstration tests. Numerical examples are then presented to demonstrate the new start-up demonstration tests. This basic idea of equipment classification can be easily extended to other traditional start-up demonstration tests.\",\n \"Title: Accelerating Data Analytics on Integrated GPU Platforms via Runtime Specialization.\\nYear: 2018\\n\\nAbstract: Integrated GPU systems are a cost-effective and energy-efficient option for accelerating data-intensive applications. While these platforms have reduced overhead of offloading computation to the GPU and potential for fine-grained resource scheduling, there remain several open challenges: (1) the distinct execution models inherent in the heterogeneous devices present on such platforms drives the need to dynamically match workload characteristics to the underlying resources, (2) the complex architecture and programming models of such systems require substantial application knowledge to achieve high performance, and (3) as such systems become prevalent, there is a need to extend their utility from running known regular data-parallel applications to the broader set of input-dependent, irregular applications common in enterprise settings. The key contribution of our research is to enable runtime specialization on such integrated GPU platforms by matching application characteristics to the underlying heterogeneous resources for both regular and irregular workloads. Our approach enables profile-driven resource management and optimizations for such platforms, providing high application performance and system throughput. Toward this end, this work proposes two novel schedulers with distinct goals: (a) a device-affinity, contention-aware scheduler that incorporates instrumentation-driven optimizations to improve the throughput of running diverse applications on integrated CPU–GPU servers, and (b) a specialized, affinity-aware work-stealing scheduler that efficiently distributes work across all CPU and GPU cores for the same application, taking into account both application characteristics and architectural differences of the underlying devices.\",\n \"Title: Enabling Elastic Stream Processing in Shared Clusters\\nYear: 2016\\n\\nAbstract: Distributed data stream processing has become an increasingly popular computational framework due to many emerging applications which require real-time processing of data such as dynamic content delivery and security event analysis. These distributed data stream processing applications are often run on shared, multi-tenant clusters as companies try to consolidate from dedicated clusters for each application (batch and streaming) to a single cluster using a global cluster manager such as Hadoop YARN. In shared cluster environments, guaranteeing the quality of service constraints for throughput and response time for both stream processing applications and batch applications is a significant challenge. Stream processing applications often face an elastic demand where the input rate can vary drastically. The typical solution to solve workload elasticity is to guarantee enough resources to the application, but this solution is not possible when resources are being shared among multiple applications. In this paper, we present an approach for supporting elastic scaling of distributed data stream processing applications and efficiently scheduling and coordinating stream processing with batch processing in shared clusters. Our solution consists of a congestion detection monitor which detects bottlenecks in the streaming system and a global state manager that performs non-disruptive, stateful scaling of streaming applications. We implemented our solution using Storm, a popular stream processing framework, and tested our implementation on a Hadoop YARN cluster using a real-time security event processing workload. Our experimental results show that our solution improves stream processing application throughput by 49% over default Storm while decreasing average request response times by 58%.\",\n \"Title: Variance Analysis For Least L(P)-Norm Estimator In Mixture Of Generalized Gaussian Noise\\nYear: 2017\\n\\nAbstract: Variance analysis is an important research topic to assess the quality of estimators. In this paper, we analyze the performance of the least l(p)-norm estimator in the presence of mixture of generalized Gaussian (MGG) noise. In the case of known density parameters, the variance expression of the l(p)-norm minimizer is first derived, for the general complex-valued signal model. Since the formula is a function of p, the optimal value of p corresponding to the minimum variance is then investigated. Simulation results show the correctness of our study and the near-optimality of the l(p)-norm minimizer compared with Cramer-Rao lower bound.\",\n \"Title: Tooth Fracture Detection in Spiral Bevel Gears System by Harmonic Response Based on Finite Element Method\\nYear: 2017\\n\\nAbstract: AbstractSpiral bevel gears occupy several advantages such as high contact ratio, strong carrying capacity, and smooth operation, which become one of the most widely used components in high-speed stage of the aeronautical transmission system. Its dynamic characteristics are addressed by many scholars. However, spiral bevel gears, especially tooth fracture occurrence and monitoring, are not to be investigated, according to the limited published issues. Therefore, this paper establishes a three-dimensional model and finite element model of the Gleason spiral bevel gear pair. The model considers the effect of tooth root fracture on the system due to fatigue. Finite element method is used to compute the mesh generation, set the boundary condition, and carry out the dynamic load. The harmonic response spectra of the base under tooth fracture are calculated and the influence of main parameters on monitoring failure is investigated as well. The results show that the change of torque affects insignificantly the determination of whether or not the system has tooth fracture. The intermediate frequency interval (200 Hz–1000 Hz) is the best interval to judge tooth fracture occurrence. The best fault test region is located in the working area where the system is going through meshing. The simulation calculation provides a theoretical reference for spiral bevel gear system test and fault diagnosis.\",\n \"Title: Resilient Distributed Estimation: Sensor Attacks.\\nYear: 2019\\n\\nAbstract: This paper studies multi-agent distributed estimation under sensor attacks. Individual agents make sensor measurements of an unknown parameter belonging to a compact set, and, at every time step, a fraction of the agentsu0027 sensor measurements may fall under attack and take arbitrary values. We present the Saturated Innovation Update (SIU) algorithm for distributed estimation resilient to sensor attacks. Under the iterative SIU algorithm, if less than one half of the agent sensors fall under attack, then, all of the agentsu0027 estimates converge at a polynomial rate (with respect to the number of iterations) to the true parameter. The resilience of SIU to sensor attacks does not depend on the topology of the inter-agent communication network, as long as it remains connected. We demonstrate the performance of SIU with numerical examples\",\n \"Title: The Internet of Things: Secure Distributed Inference.\\nYear: 2018\\n\\nAbstract: The growth in the number of devices connected to the Internet of Things (IoT) poses major challenges in security. The integrity and trustworthiness of data and data analytics are increasingly important concerns in IoT applications. These are compounded by the highly distributed nature of IoT devices, making it infeasible to prevent attacks and intrusions on all data sources. Adversaries may hijack...\",\n \"Title: Freedericksz Transition in Nematic Liquid Crystal Flows in Dimension Two\\nYear: 2018\\n\\nAbstract: this article we are concerned with the dynamical instability of liquid crystals induced by applied magnetic fields, which is the so-called Freedericksz transition. The model under consideration is the simplified Ericksen-Leslie system for a nematic liquid crystal in a magnetic field. We showed that if the magnetic field strength exceeds a threshold, any global solution converges exponentially to a unique nontrivial equilibrium solution. Here we also imposed certain initial and strong anchoring boundary conditions. It is also proved that below the threshold, the asymptotic limit is the trivial state.\",\n \"Title: A PSO-Based Ensemble Model for Peer-to-Peer Credit Scoring\\nYear: 2018\\n\\nAbstract: We propose a multi-classifier ensemble model based on particle swarm optimization (PSO) for the evaluation of personal credit risk in peer-to-peer (P2P) lending platforms. In the proposed method, we consider the differences and complementarity of the base classifiers' performance and use PSO to optimize their weights. Experimental results show that our proposed P2P personal credit scoring model outperforms both single and other benchmark ensemble models. Among the examined model variants, the ensemble model based on PSO with 100 particles is the best.\",\n \"Title: Research on personalized recommendation algorithm based on user preference in mobile e-commerce\\nYear: 2020\\n\\nAbstract: With the development of Internet, the problem of information overload becomes more and more serious. The personalized recommendation technology can establish user files through the user’s behavior and other information, and automatically recommend the items that best match the user’s preferences, thus effectively reducing the information overload problem. Based on this, this paper studies the personalized recommendation algorithm based on user preferences in mobile e-commerce. In this paper, user preference model under UTA algorithm is constructed on the basis of user rating on multiple criteria of the project, and user preference clustering is used to improve the scalability problem of personalized recommendation. Finally, the simulation is conducted according to the proposed personalized recommendation algorithm based on user preference. The simulation data use the multi-criteria rating data from 6078 users of Yahoo! Movies website for 976 movies (including 62,156 rows of data). The experimental results show that the multi-criteria recommendation algorithm (MC-CF-dis), which uses user distance similarity, has the best effect, and the MAE and RMSE value of this algorithm is about 1.2 lower than that of the other three algorithms. Accuracy is 6–10% higher than other algorithms. Thus, using this personalized recommendation algorithm based on user preference can effectively improve the quality of recommendation.\",\n \"Title: ?-Diagnosis: Unsupervised and Real-time Diagnosis of Small- window Long-tail Latency in Large-scale Microservice Platforms\\nYear: 2019\\n\\nAbstract: Microservice architectures and container technologies are broadly adopted by giant internet companies to support their web services, which typically have a strict service-level objective (SLO), tail latency, rather than average latency. However, diagnosing SLO violations, e.g., long tail latency problem, is non-trivial for large-scale web applications in shared microservice platforms due to million-level operational data and complex operational environments. \\n\\nWe identify a new type of tail latency problem for web services, small-window long-tail latency (SWLT), which is typically aggregated during a small statistical window (e.g., 1-minute or 1-second). We observe SWLT usually occurs in a small number of containers in microservice clusters and sharply shifts among different containers at different time points. To diagnose root-causes of SWLT, we propose an unsupervised and low-cost diagnosis algorithm-?-Diagnosis, using two-sample test algorithm and ?-statistics for measuring similarity of time series to identify root-cause metrics from millions of metrics. We implement and deploy a real-time diagnosis system in our real-production microservice platforms. The evaluation using real web application datasets demonstrates that ?-Diagnosis can identify all the actual root-causes at runtime and significantly reduce the candidate problem space, outperforming other time-series distance based root-cause analysis algorithms.\",\n \"Title: Selective Range Iterative Adaptive Approach for High-Resolution DOA Estimation.\\nYear: 2019\\n\\nAbstract: In this paper, the problem of direction-of-arrival (DOA) estimation for a uniform linear array with single-snapshot observations is addressed. Two non-parametric DOA estimators are developed, which can be applied in any azimuth range with one snapshot. Their main idea is iteratively updating the DOA estimates using the weighted least squares and covariance matrix. Two criteria for implementing the covariance matrix are devised, which guarantee high resolution of the proposed methods. The simulation results are included to demonstrate the superiority of our algorithms over several conventional DOA methods in terms of both estimation performance and computational complexity.\",\n \"Title: Triple-Cycle Permutations Over Finite Fields Of Characteristic Two\\nYear: 2019\\n\\nAbstract: Triple-cycle permutations over finite fields of characteristic two are studied, and some classes of triple-cycle permutations are proposed in this paper. In addition, new triple-cycle permutations can be constructed by switching construction from known ones.\",\n \"Title: A New Mathematical Modeling Method for Four-Stage Helicopter Main Gearbox and Dynamic Response Optimization.\\nYear: 2019\\n\\nAbstract: A new mathematical modeling method, namely, the finite element method and the lumped mass method (LMM-FEM) mixed modeling, is applied to establish the overall multinode dynamic model of a four-stage helicopter main gearbox. The design of structural parameters of the shaft is the critical link in the four-stage gearbox; it affects the response of multiple input and output branches; however, only the meshing pairs were frequently shown in the dynamic model in previous research. Therefore, each shaft is also treated as a single node and the shaft parameters are coupled into the dynamic equations in this method, which is more accurate for the transmission chain. The differential equations of the system are solved by the Fourier series method, and the dynamic response of each meshing element is calculated. The sensitivity analysis method and parameter optimization method are applied to obtain the key shaft parameters corresponding to each meshing element. The results show that the magnitude of dynamic response in converging meshing pair and tail output pair is higher than that of other meshing pairs, and the wall thickness has great sensitivity to a rotor shaft. In addition, the sensitivity analysis method can be used to select the corresponding shaft node efficiently and choose parameters appropriately for reducing the system response.\",\n \"Title: Tunnel crack detection using coarse‐to‐fine region localization and edge detection\\nYear: 2019\\n\\nAbstract: Detecting cracks on the concrete surface is crucial for the tunnel health monitoring and maintenance of Chinese transport facilities, since it is closely related with the structural health and reliability. The automated and efficient tunnel crack detection recently has attracted more research studies, particularly cheap availability of digital cameras makes this issue easier. However, it is still a challenging task due to concrete blebs, stains, and illumination over the concrete surface. This paper presents an efficient crack detection method in the tunnel concrete structure based on digital image processing and deep learning. Three contributions of the paper are summarized as follows. First, we collect and annotate a tunnel crack dataset including three kinds of common cracks that might benefit the research in the field. Second, we propose a new coarse-to-fine crack detection method using improved preprocessing, coarse crack region localization and classification, and fine crack edge detection. Third, we introduce a faster region convolutional neural network to develop a coarse crack region localization and classification, then deploy edge extraction to implement the fine crack edge detection, gaining a high-efficiency and high-accuracy performance. This article is categorized under: Technologies > Machine Learning Application Areas > Industry Specific Applications Technologies > Classification\",\n \"Title: Iteratively Reweighted Linear Least Squares For Frequency Estimation In Unbalanced Three-Phase Power System\\nYear: 2019\\n\\nAbstract: Smart grid has attracted increasing attention in the past decade, and one of its common problems is the variation of the nominal frequency (50 or 60 Hz) introduced by harmonics. In this paper, a batch-mode frequency estimator that can accurately obtain the deviation from the nominal frequency is proposed. The signal model, which includes not only the fundamental frequency but also the harmonics, is first defined, and its characteristic is then studied. Employing the linear prediction (LP) property of the model, the deviated frequency is iteratively updated according to the weighted LP errors, to achieve accurate fundamental frequency estimation. Computer simulations indicate that our proposed method is more accurate and reliable than the conventional estimators in the presence of harmonics and amplitude oscillation.\",\n \"Title: Secure Analytics And Resilient Inference For The Internet Of Things\\nYear: 2019\\n\\nAbstract: Internet of Things (IoT) applications for Smart Cities, such as systems for traffic control and pollution monitoring, increasingly rely on trustworthy and secure data analytics. Proper countermeasures are needed to ensure that IoT applications function reliably under security threats. This paper studies secure analytics and resilient inference for IoT in the context of recursive parameter estimation. A team of devices makes noisy measurements of an unknown parameter, and an attacker manipulates the measurement data of a subset of the devices. We present a resilient recursive estimation algorithm that processes the measurement streams to recover the value of the parameter, even when a subset of the devices fall under attack. The estimator is guaranteed to be strongly consistent - that is, the estimate converges almost surely to the value of the parameter - as long as less than half of the devices fall under attack. We illustrate the performance of the estimator through numerical examples.\",\n \"Title: Resilient Distributed Field Estimation\\nYear: 2020\\n\\nAbstract: We study resilient distributed field estimation under measurement attacks. A network of agents or devices measures a large, spatially distributed physical field parameter. An adversary arbitrarily manipulates the measurements of some of the agents. Each agent's goal is to process its measurements and information received from its neighbors to estimate only a few specific components of the field. We present SAFE, the saturating adaptive field estimator, a consensus+innovations distributed field estimator that is resilient to measurement attacks. Under sufficient conditions on the compromised measurement streams, the physical coupling between the field and the agents' measurements, and the connectivity of the cyber communication network, SAFE guarantees that each agent's estimate converges almost surely to the true value of the components of the parameter in which the agent is interested. Finally, we illustrate the performance of SAFE through numerical examples.\",\n \"Title: Non-Iterative DOA Estimation Using Discrete Fourier Transform Interpolation\\nYear: 2019\\n\\nAbstract: A fast and accurate non-iterative direction-of-arrival (DOA) estimation algorithm for multiple targets in additive white Gaussian noise is devised in this paper. The proposed estimator makes use of the two highest magnitudes discrete Fourier transform (DFT) coefficients of the input data and two of their associated neighboring bins, resulting in a deterministic complexity of O(N (1 + log(N))) with N being the number of sensors. The bias and mean squares error of the DOA estimates are analyzed. The simulation results are presented to validate the correctness of theoretical derivation and demonstrate the superiority of the devised estimator over several conventional DOA estimators.\",\n \"Title: Natural sd-RCCA Secure Public-key Encryptions from Hybrid Paradigms.\\nYear: 2019\\n\\nAbstract: The existence of natural public-key encryption (PKE) schemes satisfying secretly detectable replayable CCA (sd-RCCA) security is left as open. By introducing probabilistic message authentication codes (MACs) into popular KEM plus DEM paradigms, several instances of such schemes are presented in this paper. It is known that the encrypt-then-authenticate paradigm gives an RCCA secure DEM when the underlying MAC is regular (but not strong) secure, where forgeries for old messages might be possible. By further requiring that the validity of such forgeries can be verified only secretly, sd-RCCA secure DEMs is obtained. Combining such DEMs with CCA secure KEMs gives sd-RCCA secure hybrid PKEs. We first formalize the related notions and this paradigm, and also other variants of KEM plus DEM hybrid paradigm since MACs are commonly used in them. Then we show natural examples of desired probabilistic MACs under the standard DDH assumption, and find appropriate KEMs to match the message space for those MACs and then obtain natural instances of sd-RCCA secure hybrid PKEs.\",\n \"Title: CFS: A Distributed File System for Large Scale Container Platforms\\nYear: 2019\\n\\nAbstract: We propose CFS, a distributed file system for large scale container platforms. CFS supports both sequential and random file accesses with optimized storage for both large files and small files, and adopts different replication protocols for different write scenarios to improve the replication performance. It employs a metadata subsystem to store and distribute the file metadata across different storage nodes based on the memory usage. This metadata placement strategy avoids the need of data rebalancing during capacity expansion. CFS also provides POSIX-compliant APIs with relaxed semantics and metadata atomicity to improve the system performance. We performed a comprehensive comparison with Ceph, a widely-used distributed file system on container platforms. Our experimental results show that, in testing 7 commonly used metadata operations, CFS gives around 3 times performance boost on average. In addition, CFS exhibits better random-read/write performance in highly concurrent environments with multiple clients and processes.\",\n \"Title: Resilient Distributed Parameter Estimation with Heterogeneous Data.\\nYear: 2019\\n\\nAbstract: This paper studies resilient distributed estimation under measurement attacks. A set of agents each makes successive local, linear, noisy measurements of an unknown vector field collected in a vector parameter. The local measurement models are heterogeneous across agents and may be locally unobservable for the unknown parameter. An adversary compromises some of the measurement streams and changes their values arbitrarily. The agents’ goal is to cooperate over a peer-to-peer communication network to process their (possibly compromised) local measurements and estimate the value of the unknown vector parameter. We present \\n<bold xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">SAGE</bold>\\n, the Saturating Adaptive Gain Estimator, a distributed, recursive, consensus + innovations estimator that is resilient to measurement attacks. We demonstrate that, as long as the number of compromised measurement streams is below a particular bound, then, \\n<bold xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">SAGE</bold>\\n guarantees that all of the agents’ local estimates converge almost surely to the value of the parameter. The resilience of the estimator – i.e., the number of compromised measurement streams it can tolerate – does not depend on the topology of the inter-agent communication network. Finally, we illustrate the performance of \\n<bold xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">SAGE</bold>\\n through numerical examples.\",\n \"Title: Acoustic collision detection and localization for robot manipulators\\nYear: 2020\\n\\nAbstract: Collision detection is critical for safe robot operation in the presence of humans. Acoustic information originating from collisions between robots and objects provides opportunities for fast collision detection and localization; however, audio information from microphones on robot manipulators needs to be robustly differentiated from motors and external noise sources. In this paper, we present Panotti, the first system to efficiently detect and localize on-robot collisions using low-cost microphones. We present a novel algorithm that can localize the source of a collision with centimeter level accuracy and is also able to reject false detections using a robust spectral filtering scheme. Our method is scalable, easy to deploy, and enables safe and efficient control for robot manipulator applications. We implement and demonstrate a prototype that consists of 8 miniature microphones on a 7 degree of freedom (DOF) manipulator to validate our design. Extensive experiments show that Panotti realizes near perfect on-robot true positive collision detection rate with almost zero false detections even in high noise environments. In terms of accuracy, it achieves an average localization error of less than 3.8 cm under various experimental settings.\",\n \"Title: New Health-State Assessment Model Based On Belief Rule Base With Interpretability\\nYear: 2021\\n\\nAbstract: Health-state assessment is the foundation of optimal-maintenance decision-making for complex systems to maintain reliability and safety. Generating the assessment results in a convincing and interpretable way to avoid potential risks is of great importance. Belief rule base (BRB) as an interpretable model performs well in health-state assessment. However, the interpretability of a BRB-based model may be lost during the optimization process, which is expressed mainly as three problems: expert knowledge is not effectively used in the optimization process; the optimized rules of BRB may be in conflict with real systems; and some parameters get over-optimized, which may affect experts' initial judgment. Three concepts - \\\"searching intensity\\\", \\\"interpretability constraint of belief distribution\\\", and \\\"rule-activation factor\\\" - are defined to address these problems. Using these concepts, we propose a new health-state assessment model based on the interpretable BRB and a new optimization method to improve the accuracy and preserve the interpretability of the new model. To demonstrate the effectiveness of the proposed model, we conducted an aero-engine case study.\",\n \"Title: A Two-Stage Deep Learning Registration Method For Remote Sensing Images Based On Sub-Image Matching\\nYear: 2021\\n\\nAbstract: The registration of multi-temporal remote sensing images with abundant information and complex changes is an important preprocessing step for subsequent applications. This paper presents a novel two-stage deep learning registration method based on sub-image matching. Unlike the conventional registration framework, the proposed network learns the mapping between matched sub-images and the geometric transformation parameters directly. In the first stage, the matching of sub-images (MSI), sub-images cropped from the images are matched through the corresponding heatmaps, which are made of the predicted similarity of each sub-image pairs. The second stage, the estimation of transformation parameters (ETP), a network with weight structure and position embedding estimates the global transformation parameters from the matched pairs. The network can deal with an uncertain number of matched sub-image inputs and reduce the impact of outliers. Furthermore, the sample sharing training strategy and the augmentation based on the bounding rectangle are introduced. We evaluated our method by comparing the conventional and deep learning methods qualitatively and quantitatively on Google Earth, ISPRS, and WHU Building Datasets. The experiments showed that our method obtained the probability of correct keypoints (PCK) of over 99% at alpha = 0.05 (alpha: the normalized distance threshold) and achieved a maximum increase of 16.8% at alpha = 0.01, compared with the latest method. The results demonstrated that our method has good robustness and improved the precision in the registration of optical remote sensing images with great variation.\",\n \"Title: Multiframe Joint Enhancement for Early Interlaced Videos\\nYear: 2022\\n\\nAbstract: Early interlaced videos usually contain multiple and interlacing and complex compression artifacts, which significantly reduce the visual quality. Although the high-definition reconstruction technology for early videos has made great progress in recent years, related research on deinterlacing is still lacking. Traditional methods mainly focus on simple interlacing mechanism, and cannot deal with the complex artifacts in real-world early videos. Recent interlaced video reconstruction deep deinterlacing models only focus on single frame, while neglecting important temporal information. Therefore, this paper proposes a multiframe deinterlacing network joint enhancement network for early interlaced videos that consists of three modules, i.e., spatial vertical interpolation module, temporal alignment and fusion module, and final refinement module. The proposed method can effectively remove the complex artifacts in early videos by using temporal redundancy of multi-fields. Experimental results demonstrate that the proposed method can recover high quality results for both synthetic dataset and real-world early interlaced videos. At the same time, the method also won the first place in the MSU Deinterlacer Benchmark. The code is available at: https://github.com/anymyb/MFDIN.\",\n \"Title: Succinct Scriptable NIZK via Trusted Hardware\\nYear: 2021\\n\\nAbstract: Non-interactive zero-knowledge proof or argument (NIZK) systems are widely used in many security sensitive applications to enhance computation integrity, privacy and scalability. In such systems, a prover wants to convince one or more verifiers that the result of a public function is correctly computed without revealing the (potential) private input, such as the witness. In this work, we introduce a new notion, called succinct scriptable NIZK, where the prover and verifier(s) can specify the function (or language instance) to be proven via a script. We formalize this notion is UC framework and provide a generic trusted hardware based solution. We then instantiate our solution in both SGX and Trustzone with Lua script engine. The system can be easily used by typical programmers without any cryptographic background. The benchmark result shows that our solution is better than all the known NIZK proof systems w.r.t. prover's running time (1000 times faster), verifier's running time, and the proof size. Finally, we show how the proposed scriptable succinct NIZK can be readily deployed to solve many wellknown problems in the blockchain context, e.g. verifier's dilemma, fast joining for new players, etc..\",\n \"Title: Dynamic Median Consensus Over Random Networks.\\nYear: 2021\\n\\nAbstract: This paper studies the problem of finding the median of N distinct numbers distributed across networked agents. Each agent updates its estimate for the median from noisy local observations of one of the N numbers and information from neighbors. We consider an undirected random network that is connected on average, and a noisy observation sequence that has finite variance and almost surely decaying bias. We present a consensus+innovations algorithm with clipped innovations. Under some regularity assumptions on the network and observation model, we show that each agent's local estimate converges to the set of median(s) almost surely at an asymptotic sublinear rate. Numerical experiments demonstrate the effectiveness of the presented algorithm.\",\n \"Title: Oratosquilla Oratoria-Like Amphibious Robot Based on Dielectric Elastomer\\nYear: 2021\\n\\nAbstract: A key challenge for biologically inspired Oratosquilla oratoria amphibious robots is large deformation and flexibility. We have developed a Squilla like soft robot based on dielectric elastic materials (DE). The robot is driven by high-power dielectric elastomer and uses the principle of friction difference and water resistance difference to realize amphibious multi-mode motion. The robot is 9 cm x 5 cm x 7 cm in length, width and height, and weighs 14 g. The fastest speed on land is 12.5 cm/s, and the fastest speed on water is 2.66 cm/s. The robot has high swimming efficiency and can detect the water surface. The experimental results show that the amphibious soft robot for mantis shrimp has high potential and practicability.\",\n \"Title: Configuration Selection and Vibration Analysis of Double Layer Suspended Cable-Driven Parallel Robot for Intelligent Storage System\\nYear: 2021\\n\\nAbstract: Warehousing system plays an increasingly important role in the development of industry. However, the traditional warehousing system has the disadvantages of low efficiency, large space occupation and high maintenance difficulty, which has been unable to meet the needs of economic and social development. The demand for high efficiency and high stability intelligent storage system is more and more urgent. With the characteristics of large workspace and strong flexibility, suspended cable-driven parallel robot has great application potential in the field of intelligent storage. In this paper, the foundation of a two-layer suspended cable-driven parallel robot was proposed to meet the requirements of intelligent storage. Based on this foundation, a double layer suspended cable-driven parallel robot was established. The kinematics model of the double layer suspended cable-driven parallel robot was established, and the cable length curve in a motion period was obtained. Based on Hamilton's principle, the vibration model of the double layer suspended cable-driven parallel robot was established. The motion and vibration characteristics of the robot were analyzed in ADAMS, and the vibration law of the system was obtained.\",\n \"Title: Distraction detection of driver based on EEG signals in a simulated driving with alternative secondary task\\nYear: 2021\\n\\nAbstract: Driving distraction is a main human factor of traffic accidents. Distraction would seriously affect the drivers’ cognitive process, inducing the inability to fully perceive the surrounding environment, make the correct judgments and perform the proper operations in time. It is important to identify the drivers’ attentional state accurately and quickly during the driving process. The objective of t...\",\n \"Title: The Identification And Analysis Of Gas-Related Volcanic Features Within Chang'E-5 Landing Region\\nYear: 2021\\n\\nAbstract: Chang'e-5 (CE-5) successfully landed on the young basalts area in the northeastern Oceanus Procellarum on 1 December 2020. Recent studies on the CE-5 landing area have shown that the lack of gas-related volcanic morphology indicates that the volatile elements captured in the interior of the Moon within late-stage magma is relatively low. Typical lunar gas-related volcanic features include dark mantle deposits, volcanic pits, irregular mare patches and so on. Based on orbital images, topography, and spectral data obtained from multiple missions restricted by the morphologic and compositional characteristics of typical volcanic explosive features, this study investigated the morphological characteristics of the volcanic features in detail and found that there are three dark mantle deposits (DMDs) near the source area of Rima Mairan that have unusually low albedo and abnormally high titanium and iron content than those of the surrounding material. Combined with M-3 spectral analysis, it is shown that DMDs contain some volcanic glass components, which indicates a gas-rich explosive eruption process. In addition to DMDs, irregular mare patches (IMPs) and a volcanic depression/pit have been recognized in this area, both of which indicate a history of gas-related volcanic eruptions. Based on this study and combined with past studies, we determined the volcanic history in the source area of Rima Mairan, including both effusive and explosive volcanic activities.</p>\",\n \"Title: Species homology analysis method based on amino acid location and physicochemical properties\\nYear: 2021\\n\\nAbstract: The similarity analysis of protein sequences is a method for analyzing the homology between species. In this paper, we first encode a protein sequence into a 9 dimensional feature-vector consisting of a 20 dimensional content ratio vector, a 20 dimensional positionatio vector of the amino acids, and a 9 dimensional mean-physicochemical properties vector. Using the Euclidean distance to characterize the similarity distance of the protein sequence. We tested our method on two datasets: (1) 9 species ofND5 sequences, (2) 28 species of influenza A virus sequences. As a result, to verify the validity and practicability, we compare the correlation between the corresponding method and ClustalW.\",\n \"Title: Clustering-Aided Graph Signal Sampling and Reconstruction for Large-Scale Sensor Networks\\nYear: 2021\\n\\nAbstract: In this paper we develop a clustering-aided signal sampling and reconstruction method for data acquisition in large-scale sensor networks. Using the localization feature of a large network, we exploit the vertex-domain locality by the localized operator of each vertex on the graph, and develop a clustering method that sequentially selects cluster heads and their corresponding members by the use of...\",\n \"Title: Machine Learning based Floor-level Sensor Positioning in Smart Buildings\\nYear: 2021\\n\\nAbstract: With the emergence of new technologies, such as 5G, WiFi6, and NB-IoT, sensors are easier to be deployed in smart buildings than before, and more buildings have being built or transformed into smart buildings. Thus, how to track and locate these devices has become a problem. The traditional sensors positioning is achieved by manually recording the position of the sensor or using RSSI measurement. ...\",\n \"Title: A semi-supervised learning detection method for vision-based monitoring of construction sites by integrating teacher-student networks and data augmentation\\nYear: 2021\\n\\nAbstract: Recently, deep-learning detection methods have achieved huge success in the vision-based monitoring of construction sites in terms of safety control and productivity analysis. However, deep-learning detection methods require large-scale datasets for training purposes, and such datasets are difficult to develop due to the limited accessibility of construction images and the need for labor-intensive annotations. To address this problem, this research proposes a semi-supervised learning detection method for construction site monitoring based on teacher–student networks and data augmentation. The proposed method requires a limited number of labeled data to achieve high detection performance in construction scenarios. Initially, the proposed method trains the teacher object detector with labeled data following weak data augmentation. Next, the trained teacher object detector generates pseudo-detection results from unlabeled images that have been weakly augmented. Finally, the student object detector is trained with the pseudo-detection results and unlabeled images that have been both weakly and strongly augmented. In our experiments, 10,000 annotated construction images from the Alberta Construction Image Dataset (ACID) have been divided into a training set (70%) and a validation set (30%). The proposed method achieved a 91% mean average precision (mAP) on the validation set while only requiring 30% of the training set. In comparison, the existing supervised learning method ResNet50 Faster R-CNN achieved a mAP of 90.8% when training on the full training set. These experimental results show the potential of the proposed method in terms of reducing the time, effort, and costs spent on developing construction datasets. As such, this research has explored the potential of semi-supervised learning methods and increased the practicality of vision-based monitoring systems in the construction industry.\",\n \"Title: Dynamic COVID risk assessment accounting for community virus exposure from a spatial-temporal transmission model.\\nYear: 2021\\n\\nAbstract: COVID-19 pandemic has caused unprecedented negative impacts on our society, including further exposing inequity and disparity in public health. To study the impact of socioeconomic factors on COVID transmission, we first propose a spatial-temporal model to examine the socioeconomic heterogeneity and spatial correlation of COVID-19 transmission at the community level. Second, to assess the individual risk of severe COVID-19 outcomes after a positive diagnosis, we propose a dynamic, varying-coefficient model that integrates individual-level risk factors from electronic health records (EHRs) with community-level risk factors. The underlying neighborhood prevalence of infections (both symptomatic and pre-symptomatic) predicted from the previous spatial-temporal model is included in the individual risk assessment so as to better capture the background risk of virus exposure for each individual. We design a weighting scheme to mitigate multiple selection biases inherited in EHRs of COVID patients. We analyze COVID transmission data in New York City (NYC, the epicenter of the first surge in the United States) and EHRs from NYC hospitals, where time-varying effects of community risk factors and significant interactions between individual- and community-level risk factors are detected. By examining the socioeconomic disparity of infection risks and interaction among the risk factors, our methods can assist public health decision-making and facilitate better clinical management of COVID patients.\",\n \"Title: An IoT based parking recommendation system considering distance and parking lot flow\\nYear: 2021\\n\\nAbstract: The IoT (Internet of Things) technology and applications to facilitate \\\"smart city\\\" is developing rapidly. In this paper, we propose a parking recommendation system that confirms with the real situation that can achieve a high successful probability to obtain a free parking space when arriving at the parking lot. In our model, we divide the parking process into two parts, and use queueing theory for estimation. The first part is to estimate the driving travel time consumption of reaching the recommended parking lot after the parking demander's sending the parking request. The time is used in the second part to predict the probability of successfully obtaining a free parking space after the path driving time elapsed. Thereby, the probability of failing to obtaining a free parking space after a long way driving can be reduced. We use the SUMO traffic simulator for verification. The analysis of experiment results show that the performance is satisfactory and efficient than other related or traditional decisionmaking methods.\",\n \"Title: Development of Nursing Informatics Competencies Evaluation Index System of Clinical Nurses.\\nYear: 2021\\n\\nAbstract: For lack of effective and reliable assessment tools of nursing informatics competencies (NIC), we used literature research method, nominal group technology (NGT) and delphi technique to construct an evaluation index system of NIC for clinical nurses, which can provide reference for establishing a training system of talents of nursing informatics.\",\n \"Title: Robust Channel Estimation for 5G mm Wave Massive MIMO Relay Communication Systems\\nYear: 2021\\n\\nAbstract: Channel estimation is one of the major challenges for 5th Generation (5G) millimeter-wave (mmWave) massive multiple input multiple output (MIMO) relay communication systems. In this paper, we propose a robust channel estimation scheme for 5G mmWave massive MIMO relay communication systems. The proposed scheme takes advantage of the sparsity of the channel ofmmWave systems to further improve the ac...\",\n \"Title: A dynamic hybrid trust network-based dual-path feedback consensus model for multi-attribute group decision-making in intuitionistic fuzzy environment\\nYear: 2022\\n\\nAbstract: •A hybrid trust network is first formed and dynamically updated with iterations.•A consensus model with a dual-path feedback mechanism is constructed.•DMs can choose whether to conduct modifications while ensuring consensus efficiency.•Trust network-based modifications are recommended while minimizing adjustment cost.\",\n \"Title: Two-level differential burn-in policy for spatially heterogeneous defect units in semiconductor manufacturing\\nYear: 2021\\n\\nAbstract: Burn-in (BI) is an effective technique in semiconductor manufacturing to weed out defective devices. BI has been generally conducted on all of packaged devices for the same duration. Realizing that devices in the BI population usually have different reliability at various production levels, this study proposes a new two-level differential BI policy and two BI optimization models to determine the cost-optimal and profit-optimal BI decisions, respectively. The BI tests are conducted at two production levels: wafer-level (WL) and package-level (PL). After a common wafer-level BI for all devices, survival devices are subject to three different decisions: rejection without PLBI, acceptance without PLBI, and test with PLBI. The cost objective function consists of the BI test costs, BI failure costs, and warranty failure cost, while the profit objective function considers the manufacturing costs, BI test costs, warranty failure cost, revenue, and yield loss. Spatially varying yield and probability with reliability defects are computed via spatial regression modeling of clustered defect counts. Two numerical examples are used to illustrate the proposed BI policy and models based on the spatial defects modeling. Analytical results demonstrate that the two-level differential BI policy can be a cost- and profit-effective alternative over the conventional single PLBI policy.\",\n \"Title: A settlement safety assessment method of liquefied natural gas tank based on belief rule base\\nYear: 2021\\n\\nAbstract: In the settlement safety assessment of liquefied natural gas (LNG) tank, there are some problems, such as lack of high-value samples and uncertainty of parameters. Compared with the traditional settlement assessment method, the belief rule base (BRB) model is an effective safety assessment modeling tool by using qualitative knowledge and quantitative information to solve the lack of high-value samples and describe uncertainties. Therefore, a settlement safety assessment method of LNG tanks based on BRB is proposed in this paper. Firstly, the key factors of assessment method is established and calculated through mechanism analysis and the new Fourier series method. Then, the factor weight is determined by the information entropy method to avoid the inaccurate parameter setting caused by vagueness intrinsic to human knowledge. Finally, a case study in a 160,000 m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n LNG tank shows that it has a good performance in safety assessment.\",\n \"Title: Siamese Network Object Tracking Algorithm Combining Attention Mechanism and Correlation Filter Theory\\nYear: 2022\\n\\nAbstract: Aiming to solve the problem of tracking drift during movement, which was caused by the lack of discriminability of the feature information and the failure of a fixed template to adapt to the change of object appearance, the paper proposes an object tracking algorithm combining attention mechanism and correlation filter theory based on the framework of full convolutional Siamese neural networks. Firstly, the apparent information is processed by using the attention mechanism thought, where the object and search area features are optimized according to the spatial attention and channel attention module. At the same time, the cross-attention module is introduced to process the template branch and search area branch, respectively, which makes full use of the diversified context information of the search area. Then, the background perception correlation filter model with scale adaptation and learning rate adjustment is adopted into the model construction, using as a layer in the network model to realize the object template update. Finally, the optimal object location is determined according to the confidence map with similarity calculation. Experimental results show that the designed method in the paper can promote the object tracking performance under various challenging environments effectively; the success rate increases by 16.2%, and the accuracy rate increases by 16%.\",\n \"Title: PO-ELIC: Perception-Oriented Efficient Learned Image Coding\\nYear: 2022\\n\\nAbstract: In the past years, learned image compression (LIC) has achieved remarkable performance. The recent LIC methods outperform VVC in both PSNR and MS-SSIM. However, the low bit-rate reconstructions of LIC suffer from artifacts such as blurring, color drifting and texture missing. Moreover, those varied artifacts make image quality metrics correlate badly with human perceptual quality. In this paper, we propose PO-ELIC, i.e., Perception-Oriented Efficient Learned Image Coding. To be specific, we adapt ELIC, one of the state-of-the-art LIC models, with adversarial training techniques. We apply a mixture of losses including hinge-form adversarial loss, Charbonnier loss, and style loss, to finetune the model towards better perceptual quality. Experimental results demonstrate that our method achieves comparable perceptual quality with HiFiC with much lower bitrate.\",\n \"Title: Application-oriented Serial Interface Communication Protocols Formal Modeling Method\\nYear: 2020\\n\\nAbstract: In order to solve the formal modeling problem of non-standard application-oriented serial interface communication protocol, this paper analyzes data and data interaction relationships of the protocol, classifies these relationships into self-dependent, split/combination, inquiry and response, state transition, then respectively establishes formal mathematical models for these relationships. Using ...\",\n \"Title: Influence of trust and risk on peer-to-peer investment willingness: a bidirectional perspective\\nYear: 2022\\n\\nAbstract: Purpose The purpose of this paper is to investigate the influence of trust and perceived risk on investment willingness considering the bidirectional relationship between trust and perceived risk in peer-to-peer (P2P) lending. Design/methodology/approach Data were collected from a leading Chinese P2P platform, PPDAI.com. In total, 328 valid responses were received and analyzed using structural equation modeling (SEM). Findings The results show that the influence of trust on investment willingness is significant, whereas that of perceived risk is insignificant. The results also indicate that platform reputation has a positive effect on trust, and the quality of alternatives is positively associated with perceived risk. In addition, the bidirectional perspective should be preferred to cope with the bidirectional relationship between trust and perceived risk in P2P lending. Originality/value This study extends existing research on the influence of trust and perceived risk on investment willingness from a bidirectional perspective, which has not been addressed in the P2P lending context. In addition, this research enriches the current literature about trust and perceived risk by providing more evidence that the relationship between trust and perceived risk is bidirectional and thus the bidirectional model should be preferred. For practice, the study suggests that managers can earn trust and reduce the perceived risk of lenders by continuously providing high-quality products, services and enhancing platform reputation, ultimately improving their investment willingness.\",\n \"Title: Finite-time stabilization for delaye d quaternion-value d coupled neural networks with saturated impulse\\nYear: 2022\\n\\nAbstract: In this paper, finite-time stabilization (FTS) issue of delayed quaternion-valued coupled neural networks (DQVCNNs) with saturated impulse is discussed for the first time. Satu-rated impulse, time-varying delay and quaternion are first considered into coupled neural networks (CNNs), which makes the model more complex and realistic. Secondly, a hybrid feedback controller is designed, some conditions are derived to stabilize DQVCNNs with saturated impulse in finite time by the idea of polytopic representation and sector non-linearity model, respectively. Furthermore, this paper shows the settling-time of DQVCNNs with saturated impulse, which discloses it related to both impulse and initial state. Next, this paper also presents several corresponding essential corollaries. Lastly, the feasibility of the derived results is further explained by two examples. (c) 2022 Elsevier Inc. All rights reserved.\",\n \"Title: What Questions Are You Inclined to Answer? Effects of Hierarchy in Corporate Q&A Communities\\nYear: 2022\\n\\nAbstract: An increasing number of companies have started to implement corporate knowledge-sharing communities. Consistent with the observation in the offline setting, employees are less likely to share knowledge with individuals who have higher job ranks (i.e., higher-ups) in corporate communities such as online wikis and discussion groups. Given the importance of managers' engagements in the community and the needs for knowledge sharing across the hierarchy, we examine whether such observation persists in the corporate question-and-answer (Q&A) community, another popular type of corporate knowledge-sharing community. On the one hand, as in the offline setting and other types of communities, employees can still be reluctant to share knowledge with the higher-ranked individuals in the Q&A community. On the other hand, a Q&A community has some unique attributes that can potentially motivate employees to engage more with the higher-ups. Using a unique data set from a large corporate Q&A community and a potential-dyads approach, we find that a user is inclined to respond to a knowledge seeker whose job rank is higher than (versus lower than or the same as) the user's rank in the corporate Q&A community. We further show the causality of the result with a quasi experiment that leverages the promotions announced in our study period. Because these promotions are based on employees' performances before the existence of the community, the promotion announcements are largely exogenous to our research interest. We also find that knowledge providers exert greater effort when answering questions from the higher-ups. Finally, our analyses show that knowledge providers who post more answers to higher-ranked seekers and who display greater effort in those answers are more likely to get promoted in subsequent years. Given the critical role of knowledge sharing and the increasing prevalence of online communities, our study offers a better understanding of the knowledge-sharing pattern in the corporate Q&A community of the hierarchical organizations and delivers useful managerial implications.\",\n \"Title: The Analysis of Cones within the Tianwen-1 Landing Area\\nYear: 2022\\n\\nAbstract: On 15 May 2021, the Zhurong rover of China's first Mars mission, Tianwen-1 (TW-1), successfully landed in southern Utopia Planitia on Mars. Various landforms were present in the landing area, and this area recorded a complex geological history. Cones are one of the typical landforms in the landing area and Utopia Planitia, and they have a great significance to the local geological processes due to the diversity of their origins. Using High-Resolution Imaging Camera (HiRIC) images collected by the TW-1 orbiter, we identified a total of 272 well-preserved circular cones in the landing area. Detailed surveys of their spatial distribution, morphological characteristics, and morphometric parameters were conducted. A preliminary analysis of the surface characteristics of these cones also provides additional information to strengthen our understanding of them. The results of the high-resolution topographic analysis show that the cone heights are in the range of 10.5-90.8 m and their basal diameters range from 178.9-1206.6 m. We compared the morphometric parameters of the cones in the landing area with terrestrial and Martian analogous features and found that our measured cones are consistent with the ranges of mud volcanoes and also a small subset of igneous origin cones. However, the result of spatial analysis is more favorable to mud volcanoes, and the lower thermal inertia of the cones in the landing area compared to their surrounding materials is also a typical characteristic of mud volcanoes. Based on current evidence and analysis, we favor interpreting the cones in the TW-1 landing area as mud volcanoes.\",\n \"Title: Flooding Prognostic in Packed Columns Based on Electrical Capacitance Tomography and Convolution Neural Network\\nYear: 2022\\n\\nAbstract: The flooding of packed columns is accompanied by a steep increase in liquid hold-up and pressure drop, resulting in lower mass transfer efficiency and potential damage to equipment. This study aims to investigate, for the first time, the feasibility of electrical capacitance tomography (ECT) and convolutional neural networks (CNNs) as an intensified alternative to conventional flooding prediction methods. ECT allows variations in the predominant characteristics of flooding events to be investigated in greater detail than in previous research. Combined with CNNs, the ECT sensor enables high accuracy on liquid hold-up calculation and strong robustness against noise-contaminated measurements. In this work, a detailed comparison is made between liquid hold-up results using CNNs and a more conventional ECT method based on the Maxwell equation. Both methods can accurately calculate the liquid hold-up at low gas flow rates. The liquid hold-up predicted according to the Maxwell equation did not match the measured values at high gas flow rates, showing discrepancies of up to 68%. In contrast, CNNs are much superior to the Maxwell equation method at high gas flow rates, giving only a 1% mean of difference from the reference liquid hold-up. ECT supported by CNNs shows great fidelity for noninvasive monitoring of local liquid hold-up, allowing for more accurate, localized prediction of loading point, and flooding point in packed columns.\",\n \"Title: Developing a professional-practice-model-based nursing organizational informatics competency model\\nYear: 2022\\n\\nAbstract: •Established a scientific nursing organizational informatics competency model.•Nursing organizational informatics competency model is crucial for the healthcare organization.•Providing an action plan to develop organizational nursing informatics competencies.\",\n \"Title: Research on the Control Strategy of Battery Roller Press Deflection Device by Introducing Genetic Algorithm to Optimize Integral Separation PID\\nYear: 2022\\n\\nAbstract: At the site of continuous rolling of lithium battery electrode, most of its correction units use traditional PID control algorithms, coupled with the complex structure of the rolling equipment and the large number of control system actuators, result in the deviation of the pole piece position being controlled within 10mm only. In order to avoid the undesirable industrial problems caused by untimely correction and insufficient control accuracy, this paper proposes a control strategy for lithium battery roll press deflection device with the introduction of GA(Genetic Algorithm) optimized integral separation PID. For the problems of poor self-adaptive capability of deflection control and interference with equipment and environment during the rolling process. Analyze the causes of runout of the pole piece and the structure of the deflection correction system, establish a mathematical model and an integral separation fuzzy PID controller to realize the deflection control. Optimize the key parameters of the controller using GA to improve the control accuracy and performance of the deflection control. Simulations and experiments show that the deviation control strategy proposed in this paper can reduce the position deviation of the polar strip to within 4mm, which can effectively improve the deviation correction accuracy and the anti-interference capability of equipment operation, and also provide a good solution for the deviation control of other large and complex mechanical equipment.\",\n \"Title: Long-Term Spatiotemporal Characteristics and Impact Factors of Land Surface Temperature of Inhabited Islands with Different Urbanization Levels\\nYear: 2022\\n\\nAbstract: Surface thermal environment (STE) is closely related to the comfort and health of residents, affecting regional livability, and its spatial and temporal changes are deeply affected by the urbanization process. Considering there is a lack of effective comparative analysis on STE in different urbanized inhabited islands, the special geographical unit and vital human settlement environment, long-term spatiotemporal characteristics and impact factor quantitative analyses were performed in two inhabited islands via the RS and GIS methods. The results suggest that the surface heat amplitude of the highly urbanized Xiamen Island decreases, with the surface heat intensity continuing to increase from 2000 to 2020, while that of the lowly urbanized Kinmen Island is reversed. Although the land surface temperature (LST) of the two inhabited islands shows similar spatial distribution characteristics with evident cold/hot spots, the geographical distribution characteristics of high LST zones are significantly different, and the thermal landscape of Xiamen Island is more fragmented, discrete, and simple in shape, as revealed by the landscape metrics. We demonstrate that the area proportion between cooling land (water body and greenland) and warming land (bare land and impervious surface) is the most influential factor of LST in the two islands while the marine environment is a unique contributor to STE of inhabited islands compared with inland cities, where the seawater around the island can reduce LST over a range of distances, and the influence of elevation on LST is mostly indirect. These results provide a scientific basis and case support for understanding the STE situation of inhabited islands with different urbanization levels.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":200,"string":"200"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13349,"string":"13,349"}}},{"rowIdx":13350,"cells":{"question_id":{"kind":"string","value":"Alexandra Poulovassilis"},"question":{"kind":"string","value":"Generate an abstract for the title \"A Method for Integrating Deductive Databases\" using the following items: 1. Deductive databases \n2. Functional programming language \n3. Binary relational ER model \n4. Semi-automatic integration \n5. Identity and containment relationships"},"answer":{"kind":"string","value":". This paper presents an approach for integrating deductivedatabases. In our approach deductive databases are expressed in a functionaldatabase programming language. For integrating the extensionalparts of deductive databases, we use a binary relational ER model withsubtyping as the common data model and propose a semi-automaticmethod to perform the integration. For integrating the intentional partsof deductive databases, we formally define identity and containment relationshipsbetween..."},"correct_answer":{"kind":"string","value":". This paper presents an approach for integrating deductivedatabases. In our approach deductive databases are expressed in a functionaldatabase programming language. For integrating the extensionalparts of deductive databases, we use a binary relational ER model withsubtyping as the common data model and propose a semi-automaticmethod to perform the integration. For integrating the intentional partsof deductive databases, we formally define identity and containment relationshipsbetween..."},"documents":{"kind":"list like","value":["Title: Web Dynamics\nYear: 2002\n\nAbstract: The global usage and continuing exponential growth of the World-Wide-Web poses a host of challenges to the research community. In particular, there is an urgent need to understand and manage the dynamics of the Web, in order to develop new techniques which will make the Web tractable. We provide an overview of recent statistics relating to the size of the Web graph and its growth. We then briefly review some of the key areas relating to Web dynamics with reference to the recent literature. Finally, we summarise the talks given in a recent workshop devoted to Web dynamics which was held in the beginning of January 2001 at the University of London.","Title: A relaxed approach to RDF querying\nYear: 2006\n\nAbstract: We explore flexible querying of RDF data, with the aim of making it possible to return data satisfying query conditions with varying degrees of exactness, and also to rank the results of a query depending on how “closely” they satisfy the query conditions. We make queries more flexible by logical relaxation of their conditions based on RDFS entailment and RDFS ontologies. We develop a notion of ranking of query answers, and present a query processing algorithm for incrementally computing the relaxed answer of a query. Our approach has application in scenarios where there is a lack of understanding of the ontology underlying the data, or where the data objects have heterogeneous sets of properties or irregular structures.","Title: Report on the 3rd web dynamics workshop, at WWW'2004\nYear: 2004\n\nAbstract: The web is highly dynamic in both the content and quantity of the information that it encompasses. In order to fully exploit its enormous potential as a global repository of information, we need to understand how its size, topology, and content are evolving. This then allows the development of new techniques for locating and retrieving information that are better able to adapt and scale to its change and growth. The web's users are highly diverse and can access the it from a variety of devices and interfaces, at different places and times, and for varying purposes. Thus, new techniques are being developed for personalising the presentation and content of web-based information depending on how it is being accessed and on the individual user's requirements and preferences. New applications in areas such as e-business, sensor networks, and mobile and ubiquitous computing need to be able to detect and react quickly to events and changes in web-based information. Traditional approaches using query-based `pull' of information to find out if events or changes of interest have occurred may not be able to scale to the quantity and frequency of events and changes being generated, and new `push'-based techniques are being deployed in which information producers automatically notify consumers when events or changes of interest to them occur. Semantic Web and Web Service technologies are being developed and adopted, with the aim of providing standard ways for web-based applications to share and personalise information.","Title: Combining Information Extraction And Data Integration In The Estest System\nYear: 2006\n\nAbstract: We describe an approach which builds on techniques from Data Integration and lnformation Extraction in order to make better use of the unstructured data found in application domains such as the Semantic Web which require the integration of information from structured data sources, ontologies and text. We describe the design and implementation of the ESTEST system which integrates available structured and semi-structured data sources into a virtual global schema which is used to partially configure an information extraction process. The information extracted from the text is merged with this virtual global database and is available for query processing over the entire integrated resource. As a result of this semantic integration, new queries can now be answered which would not be possible from the structured and semi-structured data alone. We give some experimental results from the ESTEST system in use.","Title: A Pattern-Matching Algorithm For Functional Databases\nYear: 1993\n\nAbstract: In an earlier paper [The Computer Journal 35(2) 1992] the author described the implementation of a functional database language FDL addressing the storage and update of functions in some detail, but giving a limited discussion of pattern matching. In this companion paper a pattern matching algorithm is proposed which is suitable for functional databases in general and FDL in particular.","Title: An overview of PFL\nYear: 1991\n\nAbstract: A new functional database language called PFL is described. PFL is a lazy functional language with a polymorphic type inference system which enforces strong static type-checking. All functions persist in a repository, and are specified by the insertion and deletion of equations. New data types can be added at any time, and the order in which types and equations are inserted is immaterial. A class of functions called selectors are used for the storage of bulk data. Selectors allow flexible, efficient access to stored data and encourage a natural and succinct programming style. We describe the type system of PFL and the definition of functions, including selectors. We then compare PFL with logic based languages, and other functional languages. Finally, we give an extended example based upon the manufacturing company parts database of [Atk87].","Title: Query relaxation in RDF\nYear: 2008\n\nAbstract: We explore flexible querying of RDF data, with the aim of making it possible to return data satisfying query conditions with varying degrees of exactness, and also to rank the results of a query depending on how \"closely\" they satisfy the query conditions. We make queries more flexible by logical relaxation of their conditions based on RDFS entailment and RDFS ontologies. We develop a notion of ranking of query answers, and present a query processing algorithm for incrementally computing the relaxed answer of a query. Our approach has application in scenarios where there is a lack of understanding of the ontology underlying the data, or where the data objects have heterogeneous sets of properties or irregular structures.","Title: Detecting candidate named entities in search queries\nYear: 2012\n\nAbstract: The information extraction task of Named Entities Recognition (NER) has been recently applied to search engine queries, in order to better understand their semantics. Here we concentrate on the task prior to the classification of the named entities (NEs) into a set of categories, which is the problem of detecting candidate NEs via the subtask of query segmentation.We present a novel method for detecting candidate NEs using grammar annotation and query segmentation with the aid of top-n snippets from search engine results and a web n-gram model, to accurately identify NE boundaries. The proposed method addresses the problem of accurately setting boundaries of NEs and the detection of multiple NEs in queries.","Title: Analysis and optimisation of event-condition-action rules on XML\nYear: 2002\n\nAbstract: XML is now a dominant standard for storing and exchanging information. With its increasing use in areas such as data warehousing and e-commerce, there is a rapidly growing need for rule-based technology to support reactive functionality on XML repositories. Event-condition-action (ECA) rules automatically perform actions in response to events and are a natural facility to support such functionality. In this paper, we study ECA rules in the context of XML data. We define a simple language for specifying ECA rules on XML repositories. The language is illustrated by means of some examples, and its syntax and semantics are then specified more formally. We then investigate methods for analysing and optimising these ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.","Title: A Uniform Approach to Inter-model Transformations\nYear: 1999\n\nAbstract: Whilst it is a common task in systems integration to have to transform between different semantic data models, such inter-model transformations are often specified in an ad hoc manner. Further, they are usually based on transforming all data into one common data model, which may not contain suitable data constructs to model directly all aspects of the data models being integrated. Our approach is to define each of these data models in terms of a lower-level hypergraph-based data model. We show how such definitions can be used to automatically derive schema transformation operators for the higher-level data models. We also show how these higher-level transformations can be used to perform inter-model transformations, and to define inter-model links.","Title: Cluster based integration of heterogeneous biological databases using the automed toolkit\nYear: 2005\n\nAbstract: This paper presents an extensible architecture that can be used to support the integration of heterogeneous biological data sets. In our architecture, a clustering approach has been developed to support distributed biological data sources with inconsistent identification of biological objects. The architecture uses the AutoMed data integration toolkit to store the schemas of the data sources and the semi-automatically generated transformations from the source data into the data of an integrated warehouse. AutoMed supports bi-directional, extensible transformations which can be used to update the warehouse data as entities change, are added, or are deleted in the data sources. The transformations can also be used to support the addition or removal of entire data sources, or evolutions in the schemas of the data sources or of the warehouse itself. The results of using the architecture for the integration of existing genomic data sets are discussed.","Title: Event-condition-action rules on RDF metadata in P2P environments\nYear: 2006\n\nAbstract: RDF (Resource Description Framework) is one of the technologies proposed to realise the vision of the Semantic Web and it is being increasingly used in distributed Web-based applications. The use of RDF in applications that require timely notification of metadata changes raises the need for mechanisms for monitoring and processing such changes. Event-condition-action (ECA) rules are a natural candidate to fulfill this need. In this paper, we study ECA rules on RDF metadata in P2P environments. We describe a language for defining ECA rules on RDF metadata, including its syntax and execution semantics. We develop conservative tests for determining the termination and confluence of sets of such ECA rules. We describe an architecture supporting such rules in P2P environments, and our current implementation of this architecture. We also discuss techniques for relaxing the isolation and atomicity requirements of transactions.","Title: Hyperlog: A Graph-Based System for Database Browsing, Querying, and Update\nYear: 2001\n\nAbstract: Hyperlog is a declarative, graph-based language that supports database querying and update. It visualizes schema information, data, and query output as sets of nested graphs, which can be stored, browsed, and queried in a uniform way. Thus, the user need only be familiar with a very small set of syntactic constructs. Hyperlog queries consist of a set of graphs that are matched against the database. Database updates are supported by means of programs consisting of a set of rules. This paper discusses the formulation, evaluation, expressiveness, and optimization of Hyperlog queries and programs. We also describe a prototype implementation of the language and we compare and contrast our approach with work in a number of related areas, including visual database languages, graph-based data models, database update languages, and production rule systems.","Title: A nested-graph model for the representation and manipulation of complex objects\nYear: 1994\n\nAbstract: Three recent trends in database research are object-oriented and deductive databases and graph-based user interfaces. We draw these trends together in a data model we call the Hypernode Model. The single data structure of this model is the hypernode, a graph whose nodes can themselves be graphs. Hypernodes are typed, and types, too, are nested graphs. We give the theoretical foundations of hypernodes and types, and we show that type checking is tractable. We show also how conventional type-forming operators can be simulated by our graph types, including cyclic types. The Hypernode Model comes equipped with a rule-based query language called Hyperlog, which is complete with respect to computation and update. We define the operational semantics of Hyperlog and show that the evaluation can be performed efficiently. We discuss also the use of Hyperlog for supporting database browsing, an essential feature of Hypertext databases. We compare our work with other graph-based data models—unlike previous graph-based models, the Hypernode Model provides inherent support for data abstraction via its nesting of graphs. Finally, we briefly discuss the implementation of a DBMS based on the Hypernode Model.","Title: A formalisation of semantic schema integration\nYear: 1998\n\nAbstract: Several methodologies for the semantic integration of databases have been proposed in the literature. These often use a variant of the Entity-Relationship (ER) model as the common data model. To aid the schema conforming, merging and restructuring phases of the semantic integration process, various transformations have been defined that map between ER representations which are in some sense equivalent. Our work aims to formalise the notion of schema equivalence and to provide a formal underpinning for the schema integration process. We show how transformational, mapping and behavioural schema equivalence are all variants of a more general definition of schema equivalence. We propose a semantically sound set of primitive transformations and show how they can be used to express the transformations commonly used during the schema integration process and to define new transformations. We differentiate between transformations which apply to any instance of a schema and those which require knowledge-based reasoning since they apply only for certain instances; this distinction could serve to enhance the performance of transformation tools since it identifies which transformations must be verified by inspection of the schema extension; it also serves to identify when intelligent reasoning is required during the schema integration process. (C) 1998 Elsevier Science Ltd. All rights reserved.","Title: Using AutoMed metadata in data warehousing environments\nYear: 2003\n\nAbstract: What kind of metadata can be used for expressing the multiplicity of data models and the data transformation and integration processes in data warehousing environments? How can this metadata be further used for supporting other data warehouse activities? We examine how these questions are addressed by AutoMed, a system for expressing data transformation and integration processes in heterogeneous database environments.","Title: Extending the functional data model to computational completeness\nYear: 1990\n\nAbstract: We introduce the functional database language FDL which extends the functional data model to computational completeness while also supporting the persistence of any function, whether extensionally or intentionally defined. FDL improves on previous implementations of the functional data model by providing a uniform formalism both for modelling data and for computation, by supporting arbitrarily nested data types which are all persistent, and by allowing for the representation of incomplete and default knowledge. All functions are updated incrementally by the insertion and deletion of individual equations and an integrity sub-system verifies updates against the declared semantic integrity constraints.","Title: Automatic Migration and Wrapping of Database Applications - A Schema Transformation Approach\nYear: 1999\n\nAbstract: Integration of heterogeneous databases requires that semantic differences between schemas are resolved by a process of schema transformation. Previously, we have developed a general framework to support the schema transformation process, consisting of a hypergraph-based common data model and a set of primitive schema transformations defined for this model. Higher-level common data models and primitive schema transformations for them can be defined in terms of this lower-level model. In this paper, we show that a key feature of our framework is that both primitive and composite schema transformations are automatically reversible. We show how these transformations can be used to automatically migrate or wrap data, queries and updates between semantically equivalent schemas.We also show how to handle transformations between non-equivalent but overlapping schemas.We describe a prototype schema integration tool that supports this functionality. Finally, we briefly discuss how our approach can be extended to more sophisticated application logic such as constraints, deductive rules, and active rules.","Title: Implementation of a graph-based data model for complex objects\nYear: 1993\n\nAbstract: We have developed a graph-based data model called the Hypernode Model whose single data structure is the hypernode, a directed graph whose nodes may themselves reference further directed graphs. A prototype database system supporting this model is being developed at London University as part of a project whose aims are threefold: (i) to ascertain the expressiveness and flexibility of the hypernode model, (ii) to experiment with various querying paradigms for this model, and (iii) to investigate the suitability of the directed graph as a data structure supported throughout all levels of the implementation. The purpose of this paper is to report upon our findings to date.","Title: BioMap: gene family based integration of heterogeneous biological databases using AutoMed metadata\nYear: 2004\n\nAbstract: This work presents an extensible architecture that can be used to support the integration of biological data sets. Biological research frequently requires this kind of synthesis. However, the data models on which biological data sets have been constructed are heterogeneous and difficult to use together. Our architecture uses the AutoMed data integration toolkit to store the schemas of data sources, together with the transformation from these schemas into a global integrated schema. The transformation encompasses two parts; the incremental construction of a global schema which unifies the various data source schemas, and the identification of semantically identical labels for entities. Entities in the unified resource are integrated using PFS-cape. This categorises the entities into clusters based on sequence similarity, allowing the use of family information in the annotation of expression data and experimental target selection.","Title: Using schema transformation pathways for data lineage tracing\nYear: 2005\n\nAbstract: With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations.","Title: Information Sharing for the Semantic Web -a Schema Transformation Approach\nYear: 2006\n\nAbstract: This paper proposes a framework for transforming and in- tegrating heterogeneous XML data sources, making use of known cor- respondences from them to ontologies expressed in the form of RDFS schemas. The paper flrst illustrates how correspondences to a single on- tology can be exploited. The approach is then extended to the case where correspondences may refer to multiple ontologies, themselves intercon- nected via schema transformation rules. The contribution of this research is an XML-speciflc approach to the automatic transformation and inte- gration of XML data, making use of RDFS ontologies as a 'semantic bridge'. The emergence of several new standards from the World Wide Web Consortium has provided a strong basis for enhancing the interoperability of web-based ap- plications. XML is established as the common data interchange format, while RDF, RDFS and OWL provide a framework for assigning meaning to heteroge- nous web-based data. This paper proposes a framework for the automatic transformation and in- tegration of heterogeneous XML data sources by exploiting known correspon- dences between them to ontologies expressed as RDFS schemas. The transfor- mation/integration rules are expressed as both-as-view schema transformation rules in the AutoMed heterogeneous data integration system1. These rules can be used to transform an XML data source into a target format, or to integrate a set of heterogeneous XML data sources into a common format. The transforma- tion or integration may be virtual, in the sense that it allows queries posed on the target or common format to be answered by using the transformation rules and the data sources. Or the transformation/integration may be materialised, in the sense that the transformation rules can be used to generate from the data sources equivalent XML data that is structured according to the target/common format. This approach has several advantages compared with say constructing pair- wise mappings between the XML data sources, or between each data source 1 http://www.doc.ic.ac.uk/automed/","Title: Using Similarity Metrics for Matching Lifelong Learners\nYear: 2008\n\nAbstract: The L4All system provides an environment for the lifelong learner to access information about courses, personal development plans, recommendation of learning pathways, personalised support for planning of learning, and reflecting on learning. Designed as a web-based application, it offers lifelong learners the possibility to define and share their own timeline (a chronological record of their relevant life episodes) in order to foster collaborative elaboration of future goals and aspirations. A keystone for delivering such functionalities is the possibility for learner to search for `people like me'. Addressing the fact that such a definition of `people like me' is ambiguous and subjective, this paper explores the use of similarity metrics as a flexible mechanism for comparing and ranking lifelong learners' timelines.","Title: A general formal framework for schema transformation\nYear: 1998\n\nAbstract: Several methodologies for integrating database \nschemas have been proposed in \nthe literature, using various common data models (CDMs). As part of these\nmethodologies transformations have been defined that map between schemas\nwhich are in some sense equivalent. This paper describes a general\nframework for formally underpinning the schema transformation process. Our\nformalism clearly identifies which transformations apply for any instance of\nthe schema and which only for certain instances. We illustrate the\napplicability of the framework by showing how to define a set of primitive\ntransformations for an extended ER model and by defining some of the common\nschema transformations as sequences of these primitive transformations. The\nsame approach could be used to formally define transformations on other\nCDMs.","Title: Schema Evolution in Heterogeneous Database Architectures, A Schema Transformation Approach\nYear: 2002\n\nAbstract: This paper presents a new approach to schema evolution, which combines the activities of schema integration and schema evolu- tion into one framework. In previous work we have developed a general framework to support schema transformation and integration in hetero- geneous database architectures. Here we show how this framework also readily supports evolution of source schemas, allowing the global schema and the query translation pathways to be easily repaired, as opposed to having to be regenerated, after changes to source schemas.","Title: A Storage Manager for the Hypernode Model\nYear: 1992\n\nAbstract: We describe the implementation of a Storage Manager (SM) for the Hypernode model, a new data model whose aim is to integrate object-oriented and deductive databases. The single data structure of this model is the hypernode, a directed graph whose nodes may themselves be directed graphs. The components of the SM manipulate these graphs in a persistent store. The main effort of the first prototype of the SM has been to develop a modular and extensible system which can be used as a reliable and stable core for future versions. In particular, the SM caters for object-identity and referential sharing between hypernodes, large and dynamic hypernodes, clustering strategies on secondary storage, and retrieval operations which utilise indexing techniques. The main contribution of the SM is the single graph data structure which permeates throughout all the levels of the implementation; in this way efficiency can be achieved within all the components of the SM as a result of optimising this data structure, and also interfacing between the components of the SM is simple and uniform.","Title: Report on the workshop on metadata management in grid and peer-to-peer systems, London, December 16 2003\nYear: 2004\n\nAbstract: A workshop on Metadata Management in Grid and Peer-to-Peer Systems was held in the Senate House of the University of London on December 16 2003.1 The workshop was organised by the SeLeNe (Self e-Learning Networks) IST project as part of its dissemination activities.2 The goal of the workshop was to identify recent technological achievements and open challenges regarding metadata management in novel applications requiring peer-to-peer information management in a distributed or Grid setting. The target audience for this event were researchers from the Grid, peer-to-peer and e-learning communities, as well as other application areas requiring Grid and/or peer-to-peer support. The event attracted 43 participants from 8 different European countries, and we believe that it was an important step in coordinating research activities in these inter-related areas. The presentations at the workshop fell into one of four sessions, each of which we report on below.","Title: Performance modelling of Event-Condition-Action rules in P2P networks\nYear: 2011\n\nAbstract: This paper develops an analytical model for exploring the performance of processing Event-Condition-Action (ECA) rules in P2P environments, adopting as the main performance criterion the mean time required to complete all rule processing resulting from a top-level update submitted to one of the peers in the network. We examine the analytical model@?s predictions of how this time varies with the network topology, number of peers, number of rules and degree of data replication between peers. We also describe a simulation of such a P2P ECA rule processing system, and the experiments with this show good agreement with the analytical predictions. The main contributions of this paper are the analytical model itself, and the results of the performance study undertaken using the model, which have been confirmed by the results from the simulator.","Title: Design of Teacher Assistance Tools in an Exploratory Learning Environment for Algebraic Generalization\nYear: 2012\n\nAbstract: The MiGen project is designing and developing an intelligent exploratory environment to support 11-14-year-old students in their learning of algebraic generalization. Deployed within the classroom, the system also provides tools to assist teachers in monitoring students' activities and progress. This paper describes the design of these Teacher Assistance tools and gives a detailed description of one such tool, focusing in particular on the research challenges faced, and the technologies and approaches chosen to implement the necessary functionalities given the context of the project.","Title: Finding Top-k Approximate Answers to Path Queries\nYear: 2009\n\nAbstract: We consider the problem of finding and ranking paths in semistructured data without necessarily knowing its full structure. The query language we adopt comprises conjunctions of regular path queries, allowing path variables to appear in the bodies and the heads of rules, so that paths can be returned to the user. We propose an approximate query matching semantics which adapts standard notions of approximation from string matching to graph matching. Query results are returned to the user ranked in order of increasing \"distance\" to the user's original query. We show that the top-k approximate answers can be returned in polynomial time in the size of the database graph and the query.","Title: A Formal Framework for ER Schema Transformation\nYear: 1997\n\nAbstract: Several methodologies for semantic schema integration have been proposed in\nthe literature, often using some variant of the ER model as the common data\nmodel. As part of these methodologies, various transformations have been\ndefined that map between ER schemas which are in some sense equivalent.\nThis paper gives a unifying formalisation of the ER schema transformation\nprocess and shows how some common schema transformations can be expressed\nwithin this single framework. Our formalism clearly identifies which\ntransformations apply for any instance of the schema and which only for\ncertain instances.","Title: Database research challenges and opportunities of big graph data\nYear: 2013\n\nAbstract: Large volumes of graph-structured data are becoming increasingly prevalent in areas such as · social and professional network analysis · recommendation services, such as product advertisement, news and media alerts, learning resource recommendation, itinerary recommendation · scientific computing: life and health sciences, physical sciences · crime investigation and intelligence gathering · telecoms network management, for dependency analysis, root cause analysis, location-based service provision · linked open data · geospatial data · business process management: logistics, finance chains, fraud detection, risk analysis, asset management · organization management","Title: ISPIDER Central: an integrated database web-server for proteomics.\nYear: 2008\n\nAbstract: Despite the growing volumes of proteomic data, integration of the underlying results remains problematic owing to differences in formats, data captured, protein accessions and services available from the individual repositories. To address this, we present the ISPIDER Central Proteomic Database search (http://www.ispider.manchester.ac.uk/cgi-bin/ProteomicSearch.pl), an integration service offering novel search capabilities over leading, mature, proteomic repositories including PRoteomics IDEntifications database (PRIDE), PepSeeker, PeptideAtlas and the Global Proteome Machine. It enables users to search for proteins and peptides that have been characterised in mass spectrometry-based proteomics experiments from different groups, stored in different databases, and view the collated results with specialist viewers/clients. In order to overcome limitations imposed by the great variability in protein accessions used by individual laboratories, the European Bioinformatics Institutes Protein Identifier Cross-Reference (PICR) service is used to resolve accessions from different sequence repositories. Custom-built clients allow users to view peptide/protein identifications in different contexts from multiple experiments and repositories, as well as integration with the Dasty2 client supporting any annotations available from Distributed Annotation System servers. Further information on the protein hits may also be added via external web services able to take a protein as input. This web server offers the first truly integrated access to proteomics repositories and provides a unique service to biologists interested in mass spectrometry-based proteomics.","Title: A formal semantics for an active functional DBPL\nYear: 1996\n\nAbstract: . We describe how the functional database programming language PFL is extendedwith an active component without compromising either its declarative semantics or its syntax. Wegive a formal specification of the active component using PFL itself, including event specificationand detection, parameter-binding, reaction scheduling and abort handling. We describe how auser-specified function can be cast as a primitive event, and discuss the expressiveness of eventsand the optimisation of event...","Title: Building Event-Based Services for Awareness in P2P Groupware Systems\nYear: 2013\n\nAbstract: Monitoring and awareness are essential in collaborative work environments, in order to support team members' interaction and coordination processes. There has been much work in implementing awareness in web-based applications, but less so for P2P collaborative systems. P2P systems have the potential to foster more group interaction than server-based approaches, as group members can interact directly with each other and can share their knowledge, skills and resources in order to provide mutual support in the accomplishment of group tasks. Several challenges arise due to the large-scale, dynamic and heterogenous nature of P2P collaborative systems. In this paper we discuss the provision of event-based awareness services in P2P groupware systems. We first review the major requirements for such awareness functionality, and propose a structured P2P network model for meeting these requirements. We then identify a set of low level awareness services and show how these can interoperate over the P2P network in order to provide awareness as part of the P2P middleware infrastructure. Finally, we envision the use of service composition to provide more complex awareness services and we discuss the implementation of a super peer network on a Cloud platform and the provision of reliable awareness services from the Cloud.","Title: Optimising Seld Adaptive Networks by Evolving Rule-Based Agents\nYear: 1999\n\nAbstract: . The need for networks that adapt autonomously to dynamicenvironments is apparent. In this paper we describe how self adaptivenetworks can be optimised by means of agents residing on the nodes ofthe network. The knowledge of these agents is a set of active rules. Agenetic algorithm dynamically prioritises these rules in the face ofdynamically evolving conditions. To our knowledge, this is the firsttime that GAs have been used for this purpose. We demonstrate theapplicability of...","Title: Formal Foundations for Optimising Aggregation Functions in Database Programming Languages\nYear: 1997\n\nAbstract: . This paper investigates the optimisation of aggregation functionsin the context of computationally complete database programminglanguages and aims to generalise and provide a unifying formal foundationfor previous work. We define a `fold\" operator OE over collectiontypes in terms of which operations such as selection, projection, joinand group-by can be defined, as well as aggregation functions such assum, max and min. We introduce two equivalences for OE which respectivelygovern the...","Title: Event-Condition-Action Rule Languages for the Semantic Web\nYear: 2003\n\nAbstract: TheSemanticWebisbasedonXMLandRDFasitsfunda- mental standards for exchanging and storing information on the World Wide Web. Event-condition-action (ECA) rules are a natural candidate for supporting reactive functionality on XML or RDF repositories. In this paper we describe a language for ECA rules on XML and a proto- typeimplementationofthislanguage.Wealsodiscusssomepreliminary ideas regarding a language for ECA rules operating on a graph/triple representationofRDF,andwedescribethearchitectureofadistributed deployment ofsuchRDF ECArules.","Title: Implementation Of Update Operations For Interval Relations\nYear: 1994\n\nAbstract: The concept of an interval has application in diverse areas, including temporal and spatial databases, However, the semantics of set-union and set-difference are inappropriate for the update of interval relations (i.e. of relations with interval attributes). In particular, we discuss bow set-union can yield relations in which data is duplicated over several tuples and how set-difference does not implement the desired deletion semantics. This leads tis to the definition of a normalized representation for interval relations in which there is no duplication of data over several tubules: we call such relations canonical ones. We define a pair of update operations which complement set-union and set-difference, give the desired update semantics, and maintain the property of canonicity. We give algorithms for these update operations. An examination of the efficiency of these operations leads us to propose two pairs of successively more optimized operations and we give algorithms for these also. The contribution of this paper is the development of efficient algorithms for updating interval relations while maintaining the desired update semantics and preserving the non-redundancy of the data.","Title: Personalisation Services for Self E-learning Networks\nYear: 2004\n\nAbstract: This paper describes the personalisation services designed for self e-learning networks in the SeLeNe project. These include personalised search results, view definition over learning object metadata, metadata generation for composite learning objects and personalised event and change notification services.","Title: Using AutoMed for XML data transformation and integration\nYear: 2004\n\nAbstract: This paper describes how the AutoMed data integration system is be- ing extended to support the integration of heterogeneous XML documents. So far, the contributions of this research have been the development of two algorithms. One restructures the schema describing an XML document into another schema, and the other materialises an integrated schema resulting from the transformation of several source XML schemas, using the source XML data and the transforma- tion pathways between the source and integrated schemas.","Title: Manipulation operations for an interval-extended relational model\nYear: 1995\n\nAbstract: We identify semantic problems associated with the querying and updating of spatio-temporal interval data and propose operations which alleviate these problems. We first motivate two key requirements for the manipulation of such data, namely that no two tuples of a relation should intersect or be mergeable. We then examine the properties of two operations, unfold and fold, and show how they can be used to define three further operations which, respectively: eliminate intersecting or mergeable data from a relation incorporating interval attributes, yielding a so-called canonical relation; add data to a canonical relation while preserving the canonicity property; and remove data from a canonical relation while also preserving canonicity. We formally show the correctness of all these operations. An examination of their space and time requirements then leads us to define an equivalent set of optimised operations. We formally show the equivalence of the non-optimised and optimised operations, and discuss the performance gains of the latter.","Title: A Dynamic Approach to Termination Analysis for Active Database Rules\nYear: 2000\n\nAbstract: An important behavioural property for sets of active database rules is that of termination. In current commercial database systems, termination is guaranteed by imposing a fixed upper limit on the number of recursive rule firings that may occur. This can have undesirable effects such as prematurely halting correct executions. We describe a new approach based on a dynamic upper limit to the number of rule firings. This limit reflects knowledge about past rule behaviour on the database and provides a more accurate measure for when the DBMS should terminate rule execution. The approach incurs little cost and can easily be integrated with current techniques for static analysis of active rules.","Title: Searching for \"People Like Me\" in a Lifelong Learning System\nYear: 2009\n\nAbstract: The L4All system allows learners to record and share learning pathways through educational offerings, with the aim of facilitating progression from Secondary Education through to Further Education and on to Higher Education.This paper describes the design of the system's facility for searching for \"people like me\", presents the results of an evaluation session with a group of mature learners, and discusses outcomes arising from this evaluation.","Title: P2P query reformulation over both-as-view data transformation rules\nYear: 2006\n\nAbstract: The both-as-view (BAV) approach to data integration has the advantage of specifying mappings between schemas in a bidirectional manner, so that once a BAV mapping has been established between two schemas, queries may be exchanged in either direction between the schemas. In this paper we discuss the reformulation of queries over BAV transformation pathways, and demonstrate the use of this reformulation in two modes of query processing. In the first mode, public schemas are shared between peers and queries posed on the public schema can be reformulated into queries over any data sources that have been mapped to the public schema. In the second, queries are posed on the schema of a data source, and are reformulated into queries on another data source via any public schema to which both data sources have been mapped.","Title: Flexible Querying of Lifelong Learner Metadata\nYear: 2012\n\nAbstract: This paper discusses the provision of flexible querying facilities over heterogeneous data arising from lifelong learners' educational and work experiences. A key aim of such querying facilities is to allow learners to identify possible choices for their future learning and professional development by seeing what others have done. We motivate and describe the development of a prototype system, called ApproxRelax, that provides users with a graphical facility for incrementally constructing their queries and that supports both query approximation and query relaxation, thus allowing for flexible matching of users' queries against the data provided by other learners. We show how the system is able to return results in ranked order of their “distance” from the user's query. Our approach is novel both in its aim of supporting lifelong learners in reflecting on their learning and career choices, and also in its technical foundations that combine for the first time query approximation and query relaxation techniques for querying semistructured data.","Title: Bioinformatics service reconciliation by heterogeneous schema transformation\nYear: 2007\n\nAbstract: This paper focuses on the problem of bioinformatics service reconciliation in a generic and scalable manner so as to enhance interoperability in a highly evolving field. Using XML as a common representation format, but also supporting existing flat-file representation formats, we propose an approach for the scalable semi-automatic reconciliation of services, possibly invoked from within a scientific workflows tool. Service reconciliation may use the AutoMed heterogeneous data integration system as an intermediary service, or may use AutoMed to produce services that mediate between services. We discuss the application of our approach for the reconciliation of services in an example bioinformatics workflow. The main contribution of this research is an architecture for the scalable reconciliation of bioinformatics services.","Title: Ranking Approximate Answers to Semantic Web Queries\nYear: 2009\n\nAbstract: We consider the problem of a user querying semistructured data such as RDF without knowing its structure. In these circumstances, it is helpful if the querying system can perform an approximate matching of the user's query to the data and can rank the answers in terms of how closely they match the original query. Our approximate matching framework allows us to incorporate standard notions of approximation such as edit distance as well as certain RDFS inference rules, thereby capturing semantic as well as syntactic approximations. The query language we adopt comprises conjunctions of regular path queries, thus including extensions proposed for SPARQL to allow for querying paths using regular expressions. We provide an incremental query evaluation algorithm which runs in polynomial time and returns answers to the user in ranked order.","Title: The design of a system to support exploratory learning of algebraic generalisation\nYear: 2012\n\nAbstract: This paper charts the design and application of a system to support 11-14 year old students' learning of algebraic generalisation, presenting students with the means to develop their understanding of the meaning of generality, see its power for mathematics and develop algebraic ways of thinking. We focus squarely on design, while taking account of both technical and pedagogical issues and challenges, and provide an account of how we have designed and built a system with a very close fit to our knowledge of students' difficulties with the subject matter. We report the challenges involved in building a system that is both intelligent and exploratory, a learning environment in which both student and teacher are supported without explicit tutoring.","Title: Optimising Active Database Rules by Partial Evaluation and Abstract Interpretation\nYear: 2001\n\nAbstract: A key issue for active databases is optimising the execution event-condition-action rules. In this paper we show how partial evaluation provides a formal and general route to optimising such rules. We produce a specialised version of the rule execution semantics for each possible sequence of actions that may execute from the current database state. This gives the opportunity to optimise rule execution for each particular sequence of actions. We obtain information about possible sequences of rule executions actions by applying abstract interpretation to the rule execution semantics. Our techniques are applicable both statically, i.e. at rule compilation time, and dynamically, during rule execution.","Title: Configurable meta-search in the job domain\nYear: 2010\n\nAbstract: We have developed a configurable meta-search engine for the human resource domain which aims to aid job seekers in searching for job vacancies and to support meta-search providers in the rapid development of meta-search engines. A significant challenge in accessing heterogeneous, distributed information via meta-search engines is the schema/data matching and integration that is needed for resolving semantic heterogeneities between different source search engines. We adopt a hybrid approach, using multiple matching criteria and matchers. A domain-specific ontology serves as a global ontology. Mappings are derived between this and the source search engine interfaces. These mappings are used to generate an integrated meta-search query interface, support query processing in the meta-search engine, and resolve semantic conflicts arising during result extraction from the source search engines. Experiments conducted in the job search domain show that our hybrid approach increases the correctness of matching during the integration of source search interfaces.","Title: A Semantic Approach to Integrating XML and Structured Data Sources\nYear: 2001\n\nAbstract: XML is fast becoming the standard for information exchange on the WWW. As such, information expressed in XML will need to be integrated with existing information systems, which are mostly based on structured data models such as relational, object-oriented or object/ relational data models. This paper shows how our previous framework for integrating heterogeneous structured data sources can also be used for integrating XML data sources with each other and/or with other structured data sources. Our framework allows constructs from multiple modelling languages to co-exist within the same intermediate schema, and allows automatic translation of data, queries and updates between semantically equivalent or overlapping heterogenous schemas.","Title: Algebraic query optimisation for database programming languages\nYear: 1996\n\nAbstract: A major challenge still facing the designers and implementors of database programming languages (DBPLs) is that of query optimisation. We investigate algebraic query optimisation techniques for DBPLs in the context of a purely declarative functional language that supports sets as first-class objects. Since the language is computationally complete issues such as non-termination of expressions and construction of infinite data structures can be investigated, whilst its declarative nature allows the issue of side effects to be avoided and a richer set of equivalences to be developed. The language has a well-defined semantics which permits us to reason formally about the properties of expressions, such as their equivalence with other expressions and their termination. The support of a set bulk data type enables much prior work on the optimisation of relational languages to be utilised.In the paper we first give the syntax of our archetypal DBPL and briefly discuss its semantics. We then define a small but powerful algebra of operators over the set data type, provide some key equivalences for expressions in these operators, and list transformation principles for optimising expressions. Along the way, we identify some caveats to well-known equivalences for non-deductive database languages. We next extend our language with two higher level constructs commonly found in functional DBPLs: set comprehensions and functions with known inverses. Some key equivalences for these constructs are provided, as are transformation principles for expressions in them. Finally, we investigate extending our equivalences for the set operators to the analogous operators over bags. Although developed and formally proved in the context of a functional language, our findings are directly applicable to other DBPLs of similar expressiveness.","Title: Extraction and evaluation of candidate named entities in search engine queries\nYear: 2012\n\nAbstract: Named Entity Recognition (NER) has recently been applied to search queries, in order to better understand their semantics. We present a novel method for detecting candidate named entities (NEs) using grammar annotation and query segmentation with the aid of top-n snippets from search engine results, and a web n-gram model to accurately identify NE boundaries. We then evaluate this method automatically using DBpedia as a rich data source of NEs, with the aid of a small representative random sample that is manually annotated. Finally, an analysis of the types of named entities that often occur in a query log is conducted, from which a search query driven named entity taxonomy is presented.","Title: An Abstract Interpretation Framework for Termination Analysis of Active Rules\nYear: 1999\n\nAbstract: A crucial requirement for active databases is the ability to analyse the behaviour of the active rules. A particularly important type of analysis is termination analysis. We define a framework for modelling the execution of active rules, based on abstract interpretation. Specific methods for termination analysis are modelled as specific approximations within the framework. The correctness of a method can be established by proving two generic requirements provided by the framework. This affords the opportunity to compare and verify existing methods for termination analysis of active rules, and also to develop new ones.","Title: Ontology-Assisted Data Transformation and Integration\nYear: 2008\n\nAbstract: Schema-based data transformation and integration (DTI) has been an active research area for some time, while more recent advances in ontologies have led to signiflcant research in ontology-based DTI. These two approaches present some overlaps and some difierences, and in this paper we inves- tigate possible synergies between them. In particular, we show how ontologies can enhance schema-based DTI ap- proaches by providing richer semantics for schema constructs. We also illustrate one way in which schema-based DTI ap- proaches can be used together with ontology-based approaches in a heterogeneous data integration setting.","Title: Combining Inheritance and Parametric Polymorphism in a Functional Database Language\nYear: 1995\n\nAbstract: . We consider extending a functional database language tosupport subtyping, inheritance and method overloading. We do so by extendingprevious work on type inference with subtypes for the pure calculusto cater for structured types, ML-style parametric polymorphismand overloaded function definitions. We attach semantics to overloadedfunctions by developing a generalisation of best-fit pattern-matching. Althoughdeveloped for a specific language, our approach is applicable toother...","Title: Query performance evaluation of an architecture for fine-grained integration of heterogeneous grid data sources\nYear: 2010\n\nAbstract: Grid data sources may have schema- and data-level conflicts that need to be addressed using data transformation and integration technologies not supported by the current generation of Grid data access and querying middleware. We present an architecture that combines Grid data access and distributed querying with fine-grained data transformation/integration technologies, and the results of a query performance evaluation on this architecture. The performance evaluation indicates that it is indeed feasible to combine such technologies while achieving acceptable query performance. We also discuss the significance of our results for the further development of query performance over heterogeneous Grid data sources.","Title: The design of teacher assistance tools in an exploratory learning environment for mathematics generalisation\nYear: 2010\n\nAbstract: The MiGen project is designing and developing an intelligent, exploratory environment to support 11-14-year-old students in their learning of algebraic generalisation. Deployed within the classroom, the system is also providing tools to assist teachers in monitoring students' activities and progress. This paper describes the architectural design of these Teacher Assistance tools and gives a detailed description of one such tool, focussing in particular on the technologies and approaches chosen to implement the necessary functionality given the context of the project.","Title: The Conceptual and Architectural Design of a System Supporting Exploratory Learning of Mathematics Generalisation\nYear: 2009\n\nAbstract: The MiGen project is designing and developing an intelligent, exploratory environment to support 11---14-year-old students in their learning of mathematical generalisation. Deployed within the classroom, the system will also provide tools to assist teachers in monitoring students' activities and progress. This paper describes the conceptual and architectural design of the system, and gives a detailed technical explanation of a working proof-of-concept prototype of the architecture, motivating in particular the technologies and approaches chosen to implement the necessary functionality given the context of the project. We also discuss how the prototype will be used as a basis for developing the first full version of the MiGen system, in the context of ongoing knowledge acquisition and analysis within the project's iterative, stakeholder-centred design, development and testing methodology.","Title: An event-condition-action language for XML\nYear: 2002\n\nAbstract: XML repositories are now a widespread means for storing and exchanging information on the Web. As these repositories become increasingly used in dynamic applications such as e-commerce, there is a rapidly growing need for a mechanism to incorporate reactive functionality in an XML setting. Event-condition-action (ECA) rules are a technology from active databases and are a natural method for supporting suchfunctionality. ECA rules can be used for activities such as automatically enforcing document constraints, maintaining repository statistics, and facilitating publish/subscribe applications. An important question associated with the use of a ECA rules is how to statically predict their run-time behaviour. In this paper, we define a language for ECA rules on XML repositories. We then investigate methods for analysing the behaviour of a set of ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.","Title: Extending a Functional DBPL with ECA-rules\nYear: 1995\n\nAbstract: . We describe how a functional database programming languagecan be extended with transactions and ECA-rules. Fundamentalrequirements of such an extension are that the declarative semanticsof the language not be compromised, that the syntax of the languagenot be disrupted unduly, and that impedance mismatch problems beavoided. We define what we mean by events, conditions and actions anddescribe the semantics of ECA-rules with reference to event detection,parameter-binding, transaction...","Title: Abstract Interpretation for Termination Analysis in Functional Active Databases\nYear: 1999\n\nAbstract: An active database consists of a traditional database supplementedby a set of Event-Condition-Action (ECA) rules. One of the key questions for active database designers is that of termination of the ECA rules. The behaviour of the ECA rules may be obscure and their semantics isoften not specified formally.Consequently, developing termination analysis algorithms and proving theircorrectness is a challenging task.In this paper we address this problem for functional active databasesby adopting an abstract interpretation approach.By “functional active databases” we mean active databases whosetransaction execution semantics have been expressed in a purely functionallanguage. Although we demonstrate our techniques for a specific active DBMSwhich supports a functional database programming language interface, thesetechniques are directly applicable to other active DBMSs whose executionsemantics have been specified using a functional or a denotational approach.","Title: An Ontology-Based Quality Framework for Data Integration.\nYear: 2011\n\nAbstract: The data integration (DI) process involves multiple users with roles such as administrators, integrators and end-users, each of whom may have requirements which have an impact on the overall quality of an integrated resource. Users' requirements may conflict with each other, and so a quality framework for the DI context has to be capable of representing the variety of such requirements and provide mechanisms to detect and resolve the possible inconsistencies between them. This paper presents a framework for the specification of DI quality criteria and associated user requirements. This is underpinned by a Description Language formalisation with associated reasoning capabilities which enables a DI setting to be tested to identify those elements that are inconsistent with users' requirements. The application of the framework is illustrated with an example showing how it can be used to improve the quality of an integrated resource.","Title: Semi-Naive Evaluation for Hyperlog, a Graph-Based Language for Complex Objects\nYear: 1993\n\nAbstract: This paper is concerned with the evaluation of a graph-based declarative language called Hyperlog. Hyperlog is a query- and update-language for a graph-based data model called the Hypernode Model. The single data structure of this model is the hypernode — a graph whose nodes can themselves be graphs. A Hyperlog program is a set of rules whose bodies consist of templates to be matched against a database of graphs. The heads of rules are also templates and indicate the updates to the database to be undertaken for each match of the templates in the body. These updates may include the update of existing graphs or the generation of new graphs.","Title: View Generation and Optimisation in the AutoMed Data Integration Framework\nYear: 2003\n\nAbstract: In AutoMed, data integration is based on the use of re- versible sequences of schema transformations. We discuss how views can be generated from these sequences. We also discuss techniques for op- timising the views, flrstly by simplifying the transformation sequences, and secondly by optimising the view deflnitions generated from them.","Title: Data access and integration in the ISPIDER proteomics grid\nYear: 2006\n\nAbstract: Grid computing has great potential for supporting the integration of complex, fast changing biological data repositories to enable distributed data analysis. One scenario where Grid computing has such potential is provided by proteomics resources which are rapidly being developed with the emergence of affordable, reliable methods to study the proteome. The protein identifications arising from these methods derive from multiple repositories which need to be integrated to enable uniform access to them. A number of technologies exist which enable these resources to be accessed in a Grid environment, but the independent development of these resources means that significant data integration challenges, such as heterogeneity and schema evolution, have to be met. This paper presents an architecture which supports the combined use of Grid data access (OGSA-DAI), Grid distributed querying (OGSA-DQP) and data integration (AutoMed) software tools to support distributed data analysis. We discuss the application of this architecture for the integration of several autonomous proteomics data resources.","Title: Combining approximation and relaxation in semantic web path queries\nYear: 2010\n\nAbstract: We develop query relaxation techniques for regular path queries and combine them with query approximation in order to support flexible querying of RDF data when the user lacks knowledge of its full structure or where the structure is irregular. In such circumstances, it is helpful if the querying system can perform both approximate matching and relaxation of the user's query and can rank the answers according to how closely they match the original query. Our framework incorporates both standard notions of approximation based on edit distance and RDFS-based inference rules. The query language we adopt comprises conjunctions of regular path queries, thus including extensions proposed for SPARQL to allow for querying paths using regular expressions. We provide an incremental query evaluation algorithm which runs in polynomial time and returns answers to the user in ranked order.","Title: Combining Data Integration and IE Techniques to Support Partially Structured Data\nYear: 2008\n\nAbstract: A class of applications exists where the information to be stored is partially structured:that is, it consists partly of some structured data sources each conforming to a schema and partly of information left as free text. While investigating the requirements for querying partially structured data, we have encountered several limitations in the currently available approaches and we describe here three new techniques which combine aspects of Information Extraction with data integration in order to better exploit the data in these applications.","Title: A Methodology and Architecture Embedding Quality Assessment in Data Integration.\nYear: 2014\n\nAbstract: Data integration aims to combine heterogeneous information sources and to provide interfaces for accessing the integrated resource. Data integration is a collaborative task that may involve many pe...","Title: Implementing Flexible Operators for Regular Path Queries.\nYear: 2015\n\nAbstract: Given the heterogeneity of complex graph data on the web, such as RDF linked data,a user wishing to query such data may lack full knowledge of its structure and irregularities.Hence, providing users with flexible querying capabilities can be beneficial. The query language we adopt comprisesconjunctions of regular path queries, thus including extensions proposed for SPARQL 1.1 to allow for querying paths using regular expressions. To this language we add two operators: APPROX, supporting standard notions ofapproximation based on edit distance, and RELAX, which performs query relaxation based on RDFS inference rules.We describe our techniques for implementing the extended language and present a performance study undertaken on two real-world data sets. Our baseline implementation performs competitively with other automaton-based approaches, and we demonstrate empirically how various optimisations can decrease execution times of queries containing APPROX and RELAX, sometimes by orders of magnitude.","Title: Flexible Querying for SPARQL.\nYear: 2014\n\nAbstract: Flexible querying techniques can be used to enhance users' access to heterogeneous data sets, such as Linked Open Data. This paper extends SPARQL 1.1 with approximation and relaxation operators that can be applied to regular expressions for querying property paths in order to find more answers than would be returned by the exact form of a user query. We specify the semantics of the extended language and we consider the complexity of query answering with the new operators, showing that both data and query complexity are not impacted by our extensions. We present a query evaluation algorithm that returns results incrementally according to their \"distance\" from the original query. We have implemented this algorithm and have conducted preliminary trials over the YAGO SPARQL endpoint and the Lehigh University Benchmark, showing promising performance for the language extensions.","Title: Mining named entities from search engine query logs\nYear: 2014\n\nAbstract: We present a seed expansion based approach to classify named entities in web search queries. Previous approaches to this classification problem relied on contextual clues in the form of keywords surrounding a named entity in the query. Here we propose an alternative approach in the form of a Bag-of-Context-Words (BoCW) that is used to represent the context words as they appear in the snippets of the top search results for the query. This is particularly useful in the case where the query consists of only the named entity without any context words, since in the previous approaches no context is discovered. In order to construct the BoCW, we employ a novel algorithm, which iteratively expands a Class Vector that is created through expansion by gradually aggregating the BoCWs of similar named entities appearing in other queries. We provide comprehensive experimental evidence using a commercial query log showing that our approach is competitive with existing approaches.","Title: Data integration by bi-directional schema transformation rules\nYear: 2003\n\nAbstract: In this paper we describe a new approach to data integration which subsumes the previous approaches of local as view (LAV) and global as view (GAV). Our method, which we term both as view (BAV), is based on the use of reversible schema transformation sequences. We show how LAV and GAV view defl- nitions can be fully derived from BAV schema trans- formation sequences, and how BAV transformation se- quences may be partially derived from LAV or GAV view deflnitions. We also show how BAV supports the evolution of both global and local schemas, and we discuss ongoing implementation of the BAV approach within the AutoMed project.","Title: An example of the ESTEST approach to combining unstructured text and structured data\nYear: 2004\n\nAbstract: In this paper, we demonstrate the use of the ESTEST system, which combines the data integration approach with techniques from Information Extraction in order to allow information from ontologies and natural language sources to be integrated with other, semantically related, structured or semi-structured data.","Title: Flexible data integration and ontology-based data access to medical records\nYear: 2008\n\nAbstract: The ASSIST project aims to facilitate cervical cancer research by integrating medical records containing both phenotypic and genotypic data, and residing in different medical centres or hospitals. The goal of ASSIST is to enable the evaluation of medical hypotheses and the conduct of association studies in an intuitive manner, thereby allowing medical researchers to identify risk factors that can then be used at the point of care to identify women who are at high risk of developing cervical cancer. This paper presents the current status of the ASSIST medical knowledgebase. In particular, we discuss the challenges faced in constructing the ASSIST integrated resource and in enabling query processing through a domain ontology, and the solutions provided using the AutoMed heterogeneous data integration system. We focus on data cleansing issues, on data integration issues related to integrating relational medical data sources into an independent domain ontology and also on query processing. Of particular interest is the challenge of providing an easily maintainable integrated resource in a setting where the data sources and the domain ontology are developed independently and are therefore both highly likely to evolve over time.","Title: Event-Based Awareness Services For P2p Groupware Systems\nYear: 2015\n\nAbstract: P2P systems enable decentralised applications for supporting collaborating groups and communities, where the collaboration may involve both sharing of data and sharing of group processes among group members. In such applications, monitoring and awareness are critical functionalities required for an effective collaboration. However, to date there has been little research into providing generic, application-independent awareness in P2P groupware systems. We present a distributed event-based awareness approach for such systems that provides different forms of awareness through a set of interoperating, low-level awareness services. The user and technical requirements for the approach are motivated with reference to Project-Based Learning in a P2P environment. We describe the implementation of a superpeer P2P network on a Cloud platform and the provision of reliable awareness services (AaaS - Awareness as a Service) from the Cloud. We report on the outcomes of an empirical evaluation of the performance and scalability of the approach.","Title: The development of a system for supporting the lifelong learner\nYear: 2006\n\nAbstract: Given the rapidly changing skills needs of 'post-industrial economies', lifelong learning forms an integral part of government policy within the UK and abroad. However, like the UK, most economies are faced with the problem of how to reach those sections of the community that have traditionally not embraced learning and educational opportunities. In this paper, the development and evaluation of a system designed to address this problem is described. The Lifelong Learning in London for All (L4All) project has investigated the concept of 'trails' as a way of organising lifelong learning opportunities. The L4All pilot system combines a set of web services to provide the functionality needed to support this central idea. The development process was outlined, and the findings of an empirical study were used to confirm proof of concept.","Title: Learning as immersive experiences: Using the four-dimensional framework for designing and evaluating immersive learning experiences in a virtual world\nYear: 2010\n\nAbstract: Traditional approaches to learning have often focused upon knowledge transfer strategies that have centred on textually-based engagements with learners, and dialogic methods of interaction with tutors. The use of virtual worlds, with text-based, voice-based and a feeling of 'presence' naturally is allowing for more complex social interactions and designed learning experiences and role plays, as well as encouraging learner empowerment through increased interactivity. To unpick these complex social interactions and more interactive designed experiences, this paper considers the use of virtual worlds in relation to structured learning activities for college and lifelong learners. This consideration necessarily has implications upon learning theories adopted and practices taken up, with real implications for tutors and learners alike. Alongside this is the notion of learning as an ongoing set of processes mediated via social interactions and experiential learning circumstances within designed virtual and hybrid spaces. This implies the need for new methodologies for evaluating the efficacy, benefits and challenges of learning in these new ways. Towards this aim, this paper proposes an evaluation methodology for supporting the development of specified learning activities in virtual worlds, based upon inductive methods and augmented by the four-dimensional framework reported in a previous study. The study undertaken aimed to test the efficacy of the proposed evaluation methodology and framework, and to evaluate the broader uses of a virtual world for supporting lifelong learners specifically in their educational choices and career decisions. The paper presents the findings of the study and considers that virtual worlds are reorganising significantly how we relate to the design and delivery of learning. This is opening up a transition in learning predicated upon the notion of learning design through the lens of 'immersive learning experiences' rather than sets of knowledge to be transferred between tutor and learner. The challenges that remain for tutors rest with the design and delivery of these activities and experiences. The approach advocated here builds upon an incremental testing and evaluation of virtual world learning experiences.","Title: Efficient regular path query evaluation using path indexes.\nYear: 2016\n\nAbstract: We demonstrate the use of localized path indexes in generating efficient execution plans for regular path queries. This study is motivated by both the practicality of this class of queries and by the current dearth ofscalable solutions for their evaluation. Our proposed solution leverages widely available relational database technology and is often orders of magnitude faster than currently known approaches. We aim in this hands-on demonstration to both highlight the promise of our approach and to stimulate further discussion and study of engineering solutions for this practical yet challenging class of graph queries.","Title: Visualisation and Analysis of Students' Interaction Data in Exploratory earning Environments\nYear: 2015\n\nAbstract: Log files from adaptive Exploratory Learning Environments can contain prohibitively large quantities of data for visualisation and analysis. Moreover, it is hard to know in advance what data is required for analytical purposes. Using a microworld for secondary algebra as a case study, we discuss how students' interaction data can be transformed into a data warehouse in order to allow its visualisation and exploration using online analytical processing (OLAP) tools. We also present some additional, more targeted, visualisations of the students' interaction data. We demonstrate the possibilities that these visualisations provide for exploratory data analysis, enabling confirmation or contradiction of expectations that pedagogical experts may have about the system and ultimately providing both empirical evidence and insights for its further development.","Title: Scalable Monitoring of Student Interaction Indicators in Exploratory Learning Environments.\nYear: 2016\n\nAbstract: We present and evaluate a web-based architecture for monitoring student-system interaction indicators in Exploratory Learning Environments (ELEs),using as our case study a microworld for secondary school algebra. We discuss the challenging role of teachers in exploratory learning settings and motivate the need for visualisation and notification tools that can assist teachers in focusing their attention across the class and inform teachers' interventions. We present an architecture that can support such Teacher Assistance tools and demonstrate its scalability to allow concurrent usage by thousands of users (students and teachers).","Title: Design and evaluation of teacher assistance tools for exploratory learning environments.\nYear: 2016\n\nAbstract: We present our approach to designing and evaluating tools that can assist teachers in classroom settings where students are using Exploratory Learning Environments (ELEs), using as our case study the MiGen system, which targets 1114 year old students' learning of algebra. We discuss the challenging role of teachers in exploratory learning settings and motivate the need for visualisation and notification tools that can assist teachers in focusing their attention across the whole class and inform their interventions. We present the design and evaluation approach followed during the development of MiGen's Teacher Assistance tools, drawing parallels with the recently proposed LATUX workflow but also discussing how we go beyond this to include a large number of teacher participants in our evaluation activities, so as to gain the benefit of different view points. We discuss the results of the evaluations, which show that participants appreciated the capabilities of the tools and were mostly able to use them quickly and accurately.","Title: Analysing engagement in an online management programme and implications for course design.\nYear: 2016\n\nAbstract: We analyse engagement and performance data arising from participants' interactions with an in-house LMS at Imperial College London while a cohort of students follow two courses on a new online postgraduate degree in Management. We identify and investigate two main questions relating to the relationships between engagement and performance, drawing recommendations for improved guidelines to inform the design of such courses.","Title: Query Rewriting Under Linear Epsilon L Knowledge Bases\nYear: 2016\n\nAbstract: With the adoption of the recent SPARQL 1.1 standard, RDF databases are capable of directly answering more expressive queries than simple conjunctive queries. In this paper we exploit such capabilities to answer conjunctive queries (CQs) under ontologies expressed in the description logic called linear ELlin in, a restricted form of EL. In particular, we show a query answering algorithm that rewrites a given CQ into a conjunctive regular path query (CRPQ) which, evaluated on the given instance, returns the correct answer. Our technique is based on the representation of infinite unions of CQs by non-deterministic finite-state automata. Our results achieve optimal data complexity, as well as producing rewritings straightforwardly implementable in SPARQL 1.1.","Title: Approximation and relaxation of semantic web path queries.\nYear: 2016\n\nAbstract: Given the heterogeneity of complex graph data on the web, such as RDF linked data, it is likely that a user wishing to query such data will lack full knowledge of the structure of the data and of its irregularities. Hence, providing flexible querying capabilities that assist users in formulating their information seeking requirements is highly desirable. In this paper we undertake a detailed theoretical investigation of query approximation, query relaxation, and their combination, for this purpose. The query language we adopt comprises conjunctions of regular path queries, thus encompassing recent extensions to SPARQL to allow for querying paths in graphs using regular expressions (SPARQL 1.1). To this language we add standard notions of query approximation based on edit distance, as well as query relaxation based on RDFS inference rules. We show how both of these notions can be integrated into a single theoretical framework and we provide incremental evaluation algorithms that run in polynomial time in the size of the query and the data, returning answers in ranked order of their ‘distance’ from the original query. We also combine for the first time these two disparate notions into a single ‘flex’ operation that simultaneously applies both approximation and relaxation to a query conjunct, providing even greater flexibility for users, but still retaining polynomial time evaluation complexity and the ability to return query answers in ranked order.","Title: Similarity-Based Grouping to Support Teachers on Collaborative Activities in an Exploratory Mathematical Microworld.\nYear: 2017\n\nAbstract: This paper describes a computer-based tool that helps teachers group their students for collaborative activities in the context of secondary school math teaching, the challenge being to organize groups of students based on their recent work, so that their collaboration results in meaningful interactions. The complexity of the exploratory learning tasks is such that the teachers would require too l...","Title: Design and Evaluation of Adaptive Feedback to Foster ICT Information Processing Skills in Young Adults.\nYear: 2017\n\nAbstract: This paper explores the provision of adaptive hints based on attainment levels in the context of supporting the development of young adults' ICT information processing skills. We describe the design of the LIBE VLE, particularly its personalisation and adaptation features, and a User Study undertaken with young adults at a vocational education centre. Using data collected through the LIBE VLE, we analyse the relationships between learners' accessing of hints, motivation, and performance. Results point to a positive effect of accessing of hints on students' perception of the LIBE VLE and their likelihood of using it again for further learning; and also a positive effect of students' interest in the course subject on their engagement and performance in course activities. These findings have important implications for supporting young adults in developing key competences necessary for integration into the workforce and for fostering self-regulated lifelong learning.","Title: Investigations on Path Indexing for Graph Databases.\nYear: 2016\n\nAbstract: Graph databases have become an increasingly popular choice for the management of the massive network data sets arising in many contemporary applications. We investigate the effectiveness of path indexing for accelerating query processing in graph database systems, using as an exemplar the widely used open-source Neo4j graph database. We present a novel path index design which supports efficient ordered access to paths in a graph dataset. Our index is fully persistent and designed for external memory storage and retrieval. We also describe a compression scheme that exploits the limited differences between consecutive keys in the index, as well as a workload-driven approach to indexing. We demonstrate empirically the speed-ups achieved by our implementation, showing that the path index yields query run-times from 2x up to 8000x faster than Neo4j. Empirical evaluation also shows that our scheme leads to smaller indexes than using general-purpose LZ4 compression. The complete stand-alone implementation of our index, as well as supporting tooling such as a bulk-loader, are provided as open source for further research and development.","Title: Evaluating Knowledge Anchors in Data Graphs Against Basic Level Objects.\nYear: 2017\n\nAbstract: The growing number of available data graphs in the form of RDF Linked Data enables the development of semantic exploration applications in many domains. Often, the users are not domain experts and are therefore unaware of the complex knowledge structures represented in the data graphs they interact with. This hinders users’ experience and effectiveness. Our research concerns intelligent support to facilitate the exploration of data graphs by users who are not domain experts. We propose a new navigation support approach underpinned by the subsumption theory of meaningful learning, which postulates that new concepts are grasped by starting from familiar concepts which serve as knowledge anchors from where links to new knowledge are made. Our earlier work has developed several metrics and the corresponding algorithms for identifying knowledge anchors in data graphs. In this paper, we assess the performance of these algorithms by considering the user perspective and application context. The paper address the challenge of aligning basic level objects that represent familiar concepts in human cognitive structures with automatically derived knowledge anchors in data graphs. We present a systematic approach that adapts experimental methods from Cognitive Science to derive basic level objects underpinned by a data graph. This is used to evaluate knowledge anchors in data graphs in two application domains - semantic browsing (Music) and semantic search (Careers). The evaluation validates the algorithms, which enables their adoption over different domains and application contexts.","Title: Histogram Domain Ordering for Path Selectivity Estimation.\nYear: 2018\n\nAbstract: We aim to improve the accuracy of path selectivity estimation in graph databases by intelligently ordering the domain of a histogram used for estimation. This problem has not, to our knowledge, received adequate attention in the research community. We present a novel framework for the systematic study of path ordering strategies in histogram construction and use. In this framework, we introduce new ordering strategies which we experimentally demonstrate lead to significant improvement of the accuracy of path selectivity estimation over current strategies. These positive results highlight the fundamental role that domain ordering plays in the design of effective histograms for efficient and scalable graph query processing.","Title: Using Graph-based Modelling to explore changes in students' affective states during exploratory learning tasks.\nYear: 2017\n\nAbstract: This paper describes how graph-based modelling can be used to explore interactions associated with a change in studentsu0027 affective state when they are working with an exploratory learning environment (ELE). We report on a user study with an ELE that is able to detect studentsu0027 affective states from their interactions and speech. The data collected during the user study was modelled, visualized and queried as a graph. We were interested in exploring if there was a difference between low- and high-performing students in the kinds of interactions that occurred during a change in their affective state. Our findings provide new insights into how students are interacting with the ELE and the effects of the systemu0027s interventions on studentsu0027 affective states."],"string":"[\n \"Title: Web Dynamics\\nYear: 2002\\n\\nAbstract: The global usage and continuing exponential growth of the World-Wide-Web poses a host of challenges to the research community. In particular, there is an urgent need to understand and manage the dynamics of the Web, in order to develop new techniques which will make the Web tractable. We provide an overview of recent statistics relating to the size of the Web graph and its growth. We then briefly review some of the key areas relating to Web dynamics with reference to the recent literature. Finally, we summarise the talks given in a recent workshop devoted to Web dynamics which was held in the beginning of January 2001 at the University of London.\",\n \"Title: A relaxed approach to RDF querying\\nYear: 2006\\n\\nAbstract: We explore flexible querying of RDF data, with the aim of making it possible to return data satisfying query conditions with varying degrees of exactness, and also to rank the results of a query depending on how “closely” they satisfy the query conditions. We make queries more flexible by logical relaxation of their conditions based on RDFS entailment and RDFS ontologies. We develop a notion of ranking of query answers, and present a query processing algorithm for incrementally computing the relaxed answer of a query. Our approach has application in scenarios where there is a lack of understanding of the ontology underlying the data, or where the data objects have heterogeneous sets of properties or irregular structures.\",\n \"Title: Report on the 3rd web dynamics workshop, at WWW'2004\\nYear: 2004\\n\\nAbstract: The web is highly dynamic in both the content and quantity of the information that it encompasses. In order to fully exploit its enormous potential as a global repository of information, we need to understand how its size, topology, and content are evolving. This then allows the development of new techniques for locating and retrieving information that are better able to adapt and scale to its change and growth. The web's users are highly diverse and can access the it from a variety of devices and interfaces, at different places and times, and for varying purposes. Thus, new techniques are being developed for personalising the presentation and content of web-based information depending on how it is being accessed and on the individual user's requirements and preferences. New applications in areas such as e-business, sensor networks, and mobile and ubiquitous computing need to be able to detect and react quickly to events and changes in web-based information. Traditional approaches using query-based `pull' of information to find out if events or changes of interest have occurred may not be able to scale to the quantity and frequency of events and changes being generated, and new `push'-based techniques are being deployed in which information producers automatically notify consumers when events or changes of interest to them occur. Semantic Web and Web Service technologies are being developed and adopted, with the aim of providing standard ways for web-based applications to share and personalise information.\",\n \"Title: Combining Information Extraction And Data Integration In The Estest System\\nYear: 2006\\n\\nAbstract: We describe an approach which builds on techniques from Data Integration and lnformation Extraction in order to make better use of the unstructured data found in application domains such as the Semantic Web which require the integration of information from structured data sources, ontologies and text. We describe the design and implementation of the ESTEST system which integrates available structured and semi-structured data sources into a virtual global schema which is used to partially configure an information extraction process. The information extracted from the text is merged with this virtual global database and is available for query processing over the entire integrated resource. As a result of this semantic integration, new queries can now be answered which would not be possible from the structured and semi-structured data alone. We give some experimental results from the ESTEST system in use.\",\n \"Title: A Pattern-Matching Algorithm For Functional Databases\\nYear: 1993\\n\\nAbstract: In an earlier paper [The Computer Journal 35(2) 1992] the author described the implementation of a functional database language FDL addressing the storage and update of functions in some detail, but giving a limited discussion of pattern matching. In this companion paper a pattern matching algorithm is proposed which is suitable for functional databases in general and FDL in particular.\",\n \"Title: An overview of PFL\\nYear: 1991\\n\\nAbstract: A new functional database language called PFL is described. PFL is a lazy functional language with a polymorphic type inference system which enforces strong static type-checking. All functions persist in a repository, and are specified by the insertion and deletion of equations. New data types can be added at any time, and the order in which types and equations are inserted is immaterial. A class of functions called selectors are used for the storage of bulk data. Selectors allow flexible, efficient access to stored data and encourage a natural and succinct programming style. We describe the type system of PFL and the definition of functions, including selectors. We then compare PFL with logic based languages, and other functional languages. Finally, we give an extended example based upon the manufacturing company parts database of [Atk87].\",\n \"Title: Query relaxation in RDF\\nYear: 2008\\n\\nAbstract: We explore flexible querying of RDF data, with the aim of making it possible to return data satisfying query conditions with varying degrees of exactness, and also to rank the results of a query depending on how \\\"closely\\\" they satisfy the query conditions. We make queries more flexible by logical relaxation of their conditions based on RDFS entailment and RDFS ontologies. We develop a notion of ranking of query answers, and present a query processing algorithm for incrementally computing the relaxed answer of a query. Our approach has application in scenarios where there is a lack of understanding of the ontology underlying the data, or where the data objects have heterogeneous sets of properties or irregular structures.\",\n \"Title: Detecting candidate named entities in search queries\\nYear: 2012\\n\\nAbstract: The information extraction task of Named Entities Recognition (NER) has been recently applied to search engine queries, in order to better understand their semantics. Here we concentrate on the task prior to the classification of the named entities (NEs) into a set of categories, which is the problem of detecting candidate NEs via the subtask of query segmentation.We present a novel method for detecting candidate NEs using grammar annotation and query segmentation with the aid of top-n snippets from search engine results and a web n-gram model, to accurately identify NE boundaries. The proposed method addresses the problem of accurately setting boundaries of NEs and the detection of multiple NEs in queries.\",\n \"Title: Analysis and optimisation of event-condition-action rules on XML\\nYear: 2002\\n\\nAbstract: XML is now a dominant standard for storing and exchanging information. With its increasing use in areas such as data warehousing and e-commerce, there is a rapidly growing need for rule-based technology to support reactive functionality on XML repositories. Event-condition-action (ECA) rules automatically perform actions in response to events and are a natural facility to support such functionality. In this paper, we study ECA rules in the context of XML data. We define a simple language for specifying ECA rules on XML repositories. The language is illustrated by means of some examples, and its syntax and semantics are then specified more formally. We then investigate methods for analysing and optimising these ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.\",\n \"Title: A Uniform Approach to Inter-model Transformations\\nYear: 1999\\n\\nAbstract: Whilst it is a common task in systems integration to have to transform between different semantic data models, such inter-model transformations are often specified in an ad hoc manner. Further, they are usually based on transforming all data into one common data model, which may not contain suitable data constructs to model directly all aspects of the data models being integrated. Our approach is to define each of these data models in terms of a lower-level hypergraph-based data model. We show how such definitions can be used to automatically derive schema transformation operators for the higher-level data models. We also show how these higher-level transformations can be used to perform inter-model transformations, and to define inter-model links.\",\n \"Title: Cluster based integration of heterogeneous biological databases using the automed toolkit\\nYear: 2005\\n\\nAbstract: This paper presents an extensible architecture that can be used to support the integration of heterogeneous biological data sets. In our architecture, a clustering approach has been developed to support distributed biological data sources with inconsistent identification of biological objects. The architecture uses the AutoMed data integration toolkit to store the schemas of the data sources and the semi-automatically generated transformations from the source data into the data of an integrated warehouse. AutoMed supports bi-directional, extensible transformations which can be used to update the warehouse data as entities change, are added, or are deleted in the data sources. The transformations can also be used to support the addition or removal of entire data sources, or evolutions in the schemas of the data sources or of the warehouse itself. The results of using the architecture for the integration of existing genomic data sets are discussed.\",\n \"Title: Event-condition-action rules on RDF metadata in P2P environments\\nYear: 2006\\n\\nAbstract: RDF (Resource Description Framework) is one of the technologies proposed to realise the vision of the Semantic Web and it is being increasingly used in distributed Web-based applications. The use of RDF in applications that require timely notification of metadata changes raises the need for mechanisms for monitoring and processing such changes. Event-condition-action (ECA) rules are a natural candidate to fulfill this need. In this paper, we study ECA rules on RDF metadata in P2P environments. We describe a language for defining ECA rules on RDF metadata, including its syntax and execution semantics. We develop conservative tests for determining the termination and confluence of sets of such ECA rules. We describe an architecture supporting such rules in P2P environments, and our current implementation of this architecture. We also discuss techniques for relaxing the isolation and atomicity requirements of transactions.\",\n \"Title: Hyperlog: A Graph-Based System for Database Browsing, Querying, and Update\\nYear: 2001\\n\\nAbstract: Hyperlog is a declarative, graph-based language that supports database querying and update. It visualizes schema information, data, and query output as sets of nested graphs, which can be stored, browsed, and queried in a uniform way. Thus, the user need only be familiar with a very small set of syntactic constructs. Hyperlog queries consist of a set of graphs that are matched against the database. Database updates are supported by means of programs consisting of a set of rules. This paper discusses the formulation, evaluation, expressiveness, and optimization of Hyperlog queries and programs. We also describe a prototype implementation of the language and we compare and contrast our approach with work in a number of related areas, including visual database languages, graph-based data models, database update languages, and production rule systems.\",\n \"Title: A nested-graph model for the representation and manipulation of complex objects\\nYear: 1994\\n\\nAbstract: Three recent trends in database research are object-oriented and deductive databases and graph-based user interfaces. We draw these trends together in a data model we call the Hypernode Model. The single data structure of this model is the hypernode, a graph whose nodes can themselves be graphs. Hypernodes are typed, and types, too, are nested graphs. We give the theoretical foundations of hypernodes and types, and we show that type checking is tractable. We show also how conventional type-forming operators can be simulated by our graph types, including cyclic types. The Hypernode Model comes equipped with a rule-based query language called Hyperlog, which is complete with respect to computation and update. We define the operational semantics of Hyperlog and show that the evaluation can be performed efficiently. We discuss also the use of Hyperlog for supporting database browsing, an essential feature of Hypertext databases. We compare our work with other graph-based data models—unlike previous graph-based models, the Hypernode Model provides inherent support for data abstraction via its nesting of graphs. Finally, we briefly discuss the implementation of a DBMS based on the Hypernode Model.\",\n \"Title: A formalisation of semantic schema integration\\nYear: 1998\\n\\nAbstract: Several methodologies for the semantic integration of databases have been proposed in the literature. These often use a variant of the Entity-Relationship (ER) model as the common data model. To aid the schema conforming, merging and restructuring phases of the semantic integration process, various transformations have been defined that map between ER representations which are in some sense equivalent. Our work aims to formalise the notion of schema equivalence and to provide a formal underpinning for the schema integration process. We show how transformational, mapping and behavioural schema equivalence are all variants of a more general definition of schema equivalence. We propose a semantically sound set of primitive transformations and show how they can be used to express the transformations commonly used during the schema integration process and to define new transformations. We differentiate between transformations which apply to any instance of a schema and those which require knowledge-based reasoning since they apply only for certain instances; this distinction could serve to enhance the performance of transformation tools since it identifies which transformations must be verified by inspection of the schema extension; it also serves to identify when intelligent reasoning is required during the schema integration process. (C) 1998 Elsevier Science Ltd. All rights reserved.\",\n \"Title: Using AutoMed metadata in data warehousing environments\\nYear: 2003\\n\\nAbstract: What kind of metadata can be used for expressing the multiplicity of data models and the data transformation and integration processes in data warehousing environments? How can this metadata be further used for supporting other data warehouse activities? We examine how these questions are addressed by AutoMed, a system for expressing data transformation and integration processes in heterogeneous database environments.\",\n \"Title: Extending the functional data model to computational completeness\\nYear: 1990\\n\\nAbstract: We introduce the functional database language FDL which extends the functional data model to computational completeness while also supporting the persistence of any function, whether extensionally or intentionally defined. FDL improves on previous implementations of the functional data model by providing a uniform formalism both for modelling data and for computation, by supporting arbitrarily nested data types which are all persistent, and by allowing for the representation of incomplete and default knowledge. All functions are updated incrementally by the insertion and deletion of individual equations and an integrity sub-system verifies updates against the declared semantic integrity constraints.\",\n \"Title: Automatic Migration and Wrapping of Database Applications - A Schema Transformation Approach\\nYear: 1999\\n\\nAbstract: Integration of heterogeneous databases requires that semantic differences between schemas are resolved by a process of schema transformation. Previously, we have developed a general framework to support the schema transformation process, consisting of a hypergraph-based common data model and a set of primitive schema transformations defined for this model. Higher-level common data models and primitive schema transformations for them can be defined in terms of this lower-level model. In this paper, we show that a key feature of our framework is that both primitive and composite schema transformations are automatically reversible. We show how these transformations can be used to automatically migrate or wrap data, queries and updates between semantically equivalent schemas.We also show how to handle transformations between non-equivalent but overlapping schemas.We describe a prototype schema integration tool that supports this functionality. Finally, we briefly discuss how our approach can be extended to more sophisticated application logic such as constraints, deductive rules, and active rules.\",\n \"Title: Implementation of a graph-based data model for complex objects\\nYear: 1993\\n\\nAbstract: We have developed a graph-based data model called the Hypernode Model whose single data structure is the hypernode, a directed graph whose nodes may themselves reference further directed graphs. A prototype database system supporting this model is being developed at London University as part of a project whose aims are threefold: (i) to ascertain the expressiveness and flexibility of the hypernode model, (ii) to experiment with various querying paradigms for this model, and (iii) to investigate the suitability of the directed graph as a data structure supported throughout all levels of the implementation. The purpose of this paper is to report upon our findings to date.\",\n \"Title: BioMap: gene family based integration of heterogeneous biological databases using AutoMed metadata\\nYear: 2004\\n\\nAbstract: This work presents an extensible architecture that can be used to support the integration of biological data sets. Biological research frequently requires this kind of synthesis. However, the data models on which biological data sets have been constructed are heterogeneous and difficult to use together. Our architecture uses the AutoMed data integration toolkit to store the schemas of data sources, together with the transformation from these schemas into a global integrated schema. The transformation encompasses two parts; the incremental construction of a global schema which unifies the various data source schemas, and the identification of semantically identical labels for entities. Entities in the unified resource are integrated using PFS-cape. This categorises the entities into clusters based on sequence similarity, allowing the use of family information in the annotation of expression data and experimental target selection.\",\n \"Title: Using schema transformation pathways for data lineage tracing\\nYear: 2005\\n\\nAbstract: With the increasing amount and diversity of information available on the Internet, there has been a huge growth in information systems that need to integrate data from distributed, heterogeneous data sources. Tracing the lineage of the integrated data is one of the problems being addressed in data warehousing research. This paper presents a data lineage tracing approach based on schema transformation pathways. Our approach is not limited to one specific data model or query language, and would be useful in any data transformation/integration framework based on sequences of primitive schema transformations.\",\n \"Title: Information Sharing for the Semantic Web -a Schema Transformation Approach\\nYear: 2006\\n\\nAbstract: This paper proposes a framework for transforming and in- tegrating heterogeneous XML data sources, making use of known cor- respondences from them to ontologies expressed in the form of RDFS schemas. The paper flrst illustrates how correspondences to a single on- tology can be exploited. The approach is then extended to the case where correspondences may refer to multiple ontologies, themselves intercon- nected via schema transformation rules. The contribution of this research is an XML-speciflc approach to the automatic transformation and inte- gration of XML data, making use of RDFS ontologies as a 'semantic bridge'. The emergence of several new standards from the World Wide Web Consortium has provided a strong basis for enhancing the interoperability of web-based ap- plications. XML is established as the common data interchange format, while RDF, RDFS and OWL provide a framework for assigning meaning to heteroge- nous web-based data. This paper proposes a framework for the automatic transformation and in- tegration of heterogeneous XML data sources by exploiting known correspon- dences between them to ontologies expressed as RDFS schemas. The transfor- mation/integration rules are expressed as both-as-view schema transformation rules in the AutoMed heterogeneous data integration system1. These rules can be used to transform an XML data source into a target format, or to integrate a set of heterogeneous XML data sources into a common format. The transforma- tion or integration may be virtual, in the sense that it allows queries posed on the target or common format to be answered by using the transformation rules and the data sources. Or the transformation/integration may be materialised, in the sense that the transformation rules can be used to generate from the data sources equivalent XML data that is structured according to the target/common format. This approach has several advantages compared with say constructing pair- wise mappings between the XML data sources, or between each data source 1 http://www.doc.ic.ac.uk/automed/\",\n \"Title: Using Similarity Metrics for Matching Lifelong Learners\\nYear: 2008\\n\\nAbstract: The L4All system provides an environment for the lifelong learner to access information about courses, personal development plans, recommendation of learning pathways, personalised support for planning of learning, and reflecting on learning. Designed as a web-based application, it offers lifelong learners the possibility to define and share their own timeline (a chronological record of their relevant life episodes) in order to foster collaborative elaboration of future goals and aspirations. A keystone for delivering such functionalities is the possibility for learner to search for `people like me'. Addressing the fact that such a definition of `people like me' is ambiguous and subjective, this paper explores the use of similarity metrics as a flexible mechanism for comparing and ranking lifelong learners' timelines.\",\n \"Title: A general formal framework for schema transformation\\nYear: 1998\\n\\nAbstract: Several methodologies for integrating database \\nschemas have been proposed in \\nthe literature, using various common data models (CDMs). As part of these\\nmethodologies transformations have been defined that map between schemas\\nwhich are in some sense equivalent. This paper describes a general\\nframework for formally underpinning the schema transformation process. Our\\nformalism clearly identifies which transformations apply for any instance of\\nthe schema and which only for certain instances. We illustrate the\\napplicability of the framework by showing how to define a set of primitive\\ntransformations for an extended ER model and by defining some of the common\\nschema transformations as sequences of these primitive transformations. The\\nsame approach could be used to formally define transformations on other\\nCDMs.\",\n \"Title: Schema Evolution in Heterogeneous Database Architectures, A Schema Transformation Approach\\nYear: 2002\\n\\nAbstract: This paper presents a new approach to schema evolution, which combines the activities of schema integration and schema evolu- tion into one framework. In previous work we have developed a general framework to support schema transformation and integration in hetero- geneous database architectures. Here we show how this framework also readily supports evolution of source schemas, allowing the global schema and the query translation pathways to be easily repaired, as opposed to having to be regenerated, after changes to source schemas.\",\n \"Title: A Storage Manager for the Hypernode Model\\nYear: 1992\\n\\nAbstract: We describe the implementation of a Storage Manager (SM) for the Hypernode model, a new data model whose aim is to integrate object-oriented and deductive databases. The single data structure of this model is the hypernode, a directed graph whose nodes may themselves be directed graphs. The components of the SM manipulate these graphs in a persistent store. The main effort of the first prototype of the SM has been to develop a modular and extensible system which can be used as a reliable and stable core for future versions. In particular, the SM caters for object-identity and referential sharing between hypernodes, large and dynamic hypernodes, clustering strategies on secondary storage, and retrieval operations which utilise indexing techniques. The main contribution of the SM is the single graph data structure which permeates throughout all the levels of the implementation; in this way efficiency can be achieved within all the components of the SM as a result of optimising this data structure, and also interfacing between the components of the SM is simple and uniform.\",\n \"Title: Report on the workshop on metadata management in grid and peer-to-peer systems, London, December 16 2003\\nYear: 2004\\n\\nAbstract: A workshop on Metadata Management in Grid and Peer-to-Peer Systems was held in the Senate House of the University of London on December 16 2003.1 The workshop was organised by the SeLeNe (Self e-Learning Networks) IST project as part of its dissemination activities.2 The goal of the workshop was to identify recent technological achievements and open challenges regarding metadata management in novel applications requiring peer-to-peer information management in a distributed or Grid setting. The target audience for this event were researchers from the Grid, peer-to-peer and e-learning communities, as well as other application areas requiring Grid and/or peer-to-peer support. The event attracted 43 participants from 8 different European countries, and we believe that it was an important step in coordinating research activities in these inter-related areas. The presentations at the workshop fell into one of four sessions, each of which we report on below.\",\n \"Title: Performance modelling of Event-Condition-Action rules in P2P networks\\nYear: 2011\\n\\nAbstract: This paper develops an analytical model for exploring the performance of processing Event-Condition-Action (ECA) rules in P2P environments, adopting as the main performance criterion the mean time required to complete all rule processing resulting from a top-level update submitted to one of the peers in the network. We examine the analytical model@?s predictions of how this time varies with the network topology, number of peers, number of rules and degree of data replication between peers. We also describe a simulation of such a P2P ECA rule processing system, and the experiments with this show good agreement with the analytical predictions. The main contributions of this paper are the analytical model itself, and the results of the performance study undertaken using the model, which have been confirmed by the results from the simulator.\",\n \"Title: Design of Teacher Assistance Tools in an Exploratory Learning Environment for Algebraic Generalization\\nYear: 2012\\n\\nAbstract: The MiGen project is designing and developing an intelligent exploratory environment to support 11-14-year-old students in their learning of algebraic generalization. Deployed within the classroom, the system also provides tools to assist teachers in monitoring students' activities and progress. This paper describes the design of these Teacher Assistance tools and gives a detailed description of one such tool, focusing in particular on the research challenges faced, and the technologies and approaches chosen to implement the necessary functionalities given the context of the project.\",\n \"Title: Finding Top-k Approximate Answers to Path Queries\\nYear: 2009\\n\\nAbstract: We consider the problem of finding and ranking paths in semistructured data without necessarily knowing its full structure. The query language we adopt comprises conjunctions of regular path queries, allowing path variables to appear in the bodies and the heads of rules, so that paths can be returned to the user. We propose an approximate query matching semantics which adapts standard notions of approximation from string matching to graph matching. Query results are returned to the user ranked in order of increasing \\\"distance\\\" to the user's original query. We show that the top-k approximate answers can be returned in polynomial time in the size of the database graph and the query.\",\n \"Title: A Formal Framework for ER Schema Transformation\\nYear: 1997\\n\\nAbstract: Several methodologies for semantic schema integration have been proposed in\\nthe literature, often using some variant of the ER model as the common data\\nmodel. As part of these methodologies, various transformations have been\\ndefined that map between ER schemas which are in some sense equivalent.\\nThis paper gives a unifying formalisation of the ER schema transformation\\nprocess and shows how some common schema transformations can be expressed\\nwithin this single framework. Our formalism clearly identifies which\\ntransformations apply for any instance of the schema and which only for\\ncertain instances.\",\n \"Title: Database research challenges and opportunities of big graph data\\nYear: 2013\\n\\nAbstract: Large volumes of graph-structured data are becoming increasingly prevalent in areas such as · social and professional network analysis · recommendation services, such as product advertisement, news and media alerts, learning resource recommendation, itinerary recommendation · scientific computing: life and health sciences, physical sciences · crime investigation and intelligence gathering · telecoms network management, for dependency analysis, root cause analysis, location-based service provision · linked open data · geospatial data · business process management: logistics, finance chains, fraud detection, risk analysis, asset management · organization management\",\n \"Title: ISPIDER Central: an integrated database web-server for proteomics.\\nYear: 2008\\n\\nAbstract: Despite the growing volumes of proteomic data, integration of the underlying results remains problematic owing to differences in formats, data captured, protein accessions and services available from the individual repositories. To address this, we present the ISPIDER Central Proteomic Database search (http://www.ispider.manchester.ac.uk/cgi-bin/ProteomicSearch.pl), an integration service offering novel search capabilities over leading, mature, proteomic repositories including PRoteomics IDEntifications database (PRIDE), PepSeeker, PeptideAtlas and the Global Proteome Machine. It enables users to search for proteins and peptides that have been characterised in mass spectrometry-based proteomics experiments from different groups, stored in different databases, and view the collated results with specialist viewers/clients. In order to overcome limitations imposed by the great variability in protein accessions used by individual laboratories, the European Bioinformatics Institutes Protein Identifier Cross-Reference (PICR) service is used to resolve accessions from different sequence repositories. Custom-built clients allow users to view peptide/protein identifications in different contexts from multiple experiments and repositories, as well as integration with the Dasty2 client supporting any annotations available from Distributed Annotation System servers. Further information on the protein hits may also be added via external web services able to take a protein as input. This web server offers the first truly integrated access to proteomics repositories and provides a unique service to biologists interested in mass spectrometry-based proteomics.\",\n \"Title: A formal semantics for an active functional DBPL\\nYear: 1996\\n\\nAbstract: . We describe how the functional database programming language PFL is extendedwith an active component without compromising either its declarative semantics or its syntax. Wegive a formal specification of the active component using PFL itself, including event specificationand detection, parameter-binding, reaction scheduling and abort handling. We describe how auser-specified function can be cast as a primitive event, and discuss the expressiveness of eventsand the optimisation of event...\",\n \"Title: Building Event-Based Services for Awareness in P2P Groupware Systems\\nYear: 2013\\n\\nAbstract: Monitoring and awareness are essential in collaborative work environments, in order to support team members' interaction and coordination processes. There has been much work in implementing awareness in web-based applications, but less so for P2P collaborative systems. P2P systems have the potential to foster more group interaction than server-based approaches, as group members can interact directly with each other and can share their knowledge, skills and resources in order to provide mutual support in the accomplishment of group tasks. Several challenges arise due to the large-scale, dynamic and heterogenous nature of P2P collaborative systems. In this paper we discuss the provision of event-based awareness services in P2P groupware systems. We first review the major requirements for such awareness functionality, and propose a structured P2P network model for meeting these requirements. We then identify a set of low level awareness services and show how these can interoperate over the P2P network in order to provide awareness as part of the P2P middleware infrastructure. Finally, we envision the use of service composition to provide more complex awareness services and we discuss the implementation of a super peer network on a Cloud platform and the provision of reliable awareness services from the Cloud.\",\n \"Title: Optimising Seld Adaptive Networks by Evolving Rule-Based Agents\\nYear: 1999\\n\\nAbstract: . The need for networks that adapt autonomously to dynamicenvironments is apparent. In this paper we describe how self adaptivenetworks can be optimised by means of agents residing on the nodes ofthe network. The knowledge of these agents is a set of active rules. Agenetic algorithm dynamically prioritises these rules in the face ofdynamically evolving conditions. To our knowledge, this is the firsttime that GAs have been used for this purpose. We demonstrate theapplicability of...\",\n \"Title: Formal Foundations for Optimising Aggregation Functions in Database Programming Languages\\nYear: 1997\\n\\nAbstract: . This paper investigates the optimisation of aggregation functionsin the context of computationally complete database programminglanguages and aims to generalise and provide a unifying formal foundationfor previous work. We define a `fold\\\" operator OE over collectiontypes in terms of which operations such as selection, projection, joinand group-by can be defined, as well as aggregation functions such assum, max and min. We introduce two equivalences for OE which respectivelygovern the...\",\n \"Title: Event-Condition-Action Rule Languages for the Semantic Web\\nYear: 2003\\n\\nAbstract: TheSemanticWebisbasedonXMLandRDFasitsfunda- mental standards for exchanging and storing information on the World Wide Web. Event-condition-action (ECA) rules are a natural candidate for supporting reactive functionality on XML or RDF repositories. In this paper we describe a language for ECA rules on XML and a proto- typeimplementationofthislanguage.Wealsodiscusssomepreliminary ideas regarding a language for ECA rules operating on a graph/triple representationofRDF,andwedescribethearchitectureofadistributed deployment ofsuchRDF ECArules.\",\n \"Title: Implementation Of Update Operations For Interval Relations\\nYear: 1994\\n\\nAbstract: The concept of an interval has application in diverse areas, including temporal and spatial databases, However, the semantics of set-union and set-difference are inappropriate for the update of interval relations (i.e. of relations with interval attributes). In particular, we discuss bow set-union can yield relations in which data is duplicated over several tuples and how set-difference does not implement the desired deletion semantics. This leads tis to the definition of a normalized representation for interval relations in which there is no duplication of data over several tubules: we call such relations canonical ones. We define a pair of update operations which complement set-union and set-difference, give the desired update semantics, and maintain the property of canonicity. We give algorithms for these update operations. An examination of the efficiency of these operations leads us to propose two pairs of successively more optimized operations and we give algorithms for these also. The contribution of this paper is the development of efficient algorithms for updating interval relations while maintaining the desired update semantics and preserving the non-redundancy of the data.\",\n \"Title: Personalisation Services for Self E-learning Networks\\nYear: 2004\\n\\nAbstract: This paper describes the personalisation services designed for self e-learning networks in the SeLeNe project. These include personalised search results, view definition over learning object metadata, metadata generation for composite learning objects and personalised event and change notification services.\",\n \"Title: Using AutoMed for XML data transformation and integration\\nYear: 2004\\n\\nAbstract: This paper describes how the AutoMed data integration system is be- ing extended to support the integration of heterogeneous XML documents. So far, the contributions of this research have been the development of two algorithms. One restructures the schema describing an XML document into another schema, and the other materialises an integrated schema resulting from the transformation of several source XML schemas, using the source XML data and the transforma- tion pathways between the source and integrated schemas.\",\n \"Title: Manipulation operations for an interval-extended relational model\\nYear: 1995\\n\\nAbstract: We identify semantic problems associated with the querying and updating of spatio-temporal interval data and propose operations which alleviate these problems. We first motivate two key requirements for the manipulation of such data, namely that no two tuples of a relation should intersect or be mergeable. We then examine the properties of two operations, unfold and fold, and show how they can be used to define three further operations which, respectively: eliminate intersecting or mergeable data from a relation incorporating interval attributes, yielding a so-called canonical relation; add data to a canonical relation while preserving the canonicity property; and remove data from a canonical relation while also preserving canonicity. We formally show the correctness of all these operations. An examination of their space and time requirements then leads us to define an equivalent set of optimised operations. We formally show the equivalence of the non-optimised and optimised operations, and discuss the performance gains of the latter.\",\n \"Title: A Dynamic Approach to Termination Analysis for Active Database Rules\\nYear: 2000\\n\\nAbstract: An important behavioural property for sets of active database rules is that of termination. In current commercial database systems, termination is guaranteed by imposing a fixed upper limit on the number of recursive rule firings that may occur. This can have undesirable effects such as prematurely halting correct executions. We describe a new approach based on a dynamic upper limit to the number of rule firings. This limit reflects knowledge about past rule behaviour on the database and provides a more accurate measure for when the DBMS should terminate rule execution. The approach incurs little cost and can easily be integrated with current techniques for static analysis of active rules.\",\n \"Title: Searching for \\\"People Like Me\\\" in a Lifelong Learning System\\nYear: 2009\\n\\nAbstract: The L4All system allows learners to record and share learning pathways through educational offerings, with the aim of facilitating progression from Secondary Education through to Further Education and on to Higher Education.This paper describes the design of the system's facility for searching for \\\"people like me\\\", presents the results of an evaluation session with a group of mature learners, and discusses outcomes arising from this evaluation.\",\n \"Title: P2P query reformulation over both-as-view data transformation rules\\nYear: 2006\\n\\nAbstract: The both-as-view (BAV) approach to data integration has the advantage of specifying mappings between schemas in a bidirectional manner, so that once a BAV mapping has been established between two schemas, queries may be exchanged in either direction between the schemas. In this paper we discuss the reformulation of queries over BAV transformation pathways, and demonstrate the use of this reformulation in two modes of query processing. In the first mode, public schemas are shared between peers and queries posed on the public schema can be reformulated into queries over any data sources that have been mapped to the public schema. In the second, queries are posed on the schema of a data source, and are reformulated into queries on another data source via any public schema to which both data sources have been mapped.\",\n \"Title: Flexible Querying of Lifelong Learner Metadata\\nYear: 2012\\n\\nAbstract: This paper discusses the provision of flexible querying facilities over heterogeneous data arising from lifelong learners' educational and work experiences. A key aim of such querying facilities is to allow learners to identify possible choices for their future learning and professional development by seeing what others have done. We motivate and describe the development of a prototype system, called ApproxRelax, that provides users with a graphical facility for incrementally constructing their queries and that supports both query approximation and query relaxation, thus allowing for flexible matching of users' queries against the data provided by other learners. We show how the system is able to return results in ranked order of their “distance” from the user's query. Our approach is novel both in its aim of supporting lifelong learners in reflecting on their learning and career choices, and also in its technical foundations that combine for the first time query approximation and query relaxation techniques for querying semistructured data.\",\n \"Title: Bioinformatics service reconciliation by heterogeneous schema transformation\\nYear: 2007\\n\\nAbstract: This paper focuses on the problem of bioinformatics service reconciliation in a generic and scalable manner so as to enhance interoperability in a highly evolving field. Using XML as a common representation format, but also supporting existing flat-file representation formats, we propose an approach for the scalable semi-automatic reconciliation of services, possibly invoked from within a scientific workflows tool. Service reconciliation may use the AutoMed heterogeneous data integration system as an intermediary service, or may use AutoMed to produce services that mediate between services. We discuss the application of our approach for the reconciliation of services in an example bioinformatics workflow. The main contribution of this research is an architecture for the scalable reconciliation of bioinformatics services.\",\n \"Title: Ranking Approximate Answers to Semantic Web Queries\\nYear: 2009\\n\\nAbstract: We consider the problem of a user querying semistructured data such as RDF without knowing its structure. In these circumstances, it is helpful if the querying system can perform an approximate matching of the user's query to the data and can rank the answers in terms of how closely they match the original query. Our approximate matching framework allows us to incorporate standard notions of approximation such as edit distance as well as certain RDFS inference rules, thereby capturing semantic as well as syntactic approximations. The query language we adopt comprises conjunctions of regular path queries, thus including extensions proposed for SPARQL to allow for querying paths using regular expressions. We provide an incremental query evaluation algorithm which runs in polynomial time and returns answers to the user in ranked order.\",\n \"Title: The design of a system to support exploratory learning of algebraic generalisation\\nYear: 2012\\n\\nAbstract: This paper charts the design and application of a system to support 11-14 year old students' learning of algebraic generalisation, presenting students with the means to develop their understanding of the meaning of generality, see its power for mathematics and develop algebraic ways of thinking. We focus squarely on design, while taking account of both technical and pedagogical issues and challenges, and provide an account of how we have designed and built a system with a very close fit to our knowledge of students' difficulties with the subject matter. We report the challenges involved in building a system that is both intelligent and exploratory, a learning environment in which both student and teacher are supported without explicit tutoring.\",\n \"Title: Optimising Active Database Rules by Partial Evaluation and Abstract Interpretation\\nYear: 2001\\n\\nAbstract: A key issue for active databases is optimising the execution event-condition-action rules. In this paper we show how partial evaluation provides a formal and general route to optimising such rules. We produce a specialised version of the rule execution semantics for each possible sequence of actions that may execute from the current database state. This gives the opportunity to optimise rule execution for each particular sequence of actions. We obtain information about possible sequences of rule executions actions by applying abstract interpretation to the rule execution semantics. Our techniques are applicable both statically, i.e. at rule compilation time, and dynamically, during rule execution.\",\n \"Title: Configurable meta-search in the job domain\\nYear: 2010\\n\\nAbstract: We have developed a configurable meta-search engine for the human resource domain which aims to aid job seekers in searching for job vacancies and to support meta-search providers in the rapid development of meta-search engines. A significant challenge in accessing heterogeneous, distributed information via meta-search engines is the schema/data matching and integration that is needed for resolving semantic heterogeneities between different source search engines. We adopt a hybrid approach, using multiple matching criteria and matchers. A domain-specific ontology serves as a global ontology. Mappings are derived between this and the source search engine interfaces. These mappings are used to generate an integrated meta-search query interface, support query processing in the meta-search engine, and resolve semantic conflicts arising during result extraction from the source search engines. Experiments conducted in the job search domain show that our hybrid approach increases the correctness of matching during the integration of source search interfaces.\",\n \"Title: A Semantic Approach to Integrating XML and Structured Data Sources\\nYear: 2001\\n\\nAbstract: XML is fast becoming the standard for information exchange on the WWW. As such, information expressed in XML will need to be integrated with existing information systems, which are mostly based on structured data models such as relational, object-oriented or object/ relational data models. This paper shows how our previous framework for integrating heterogeneous structured data sources can also be used for integrating XML data sources with each other and/or with other structured data sources. Our framework allows constructs from multiple modelling languages to co-exist within the same intermediate schema, and allows automatic translation of data, queries and updates between semantically equivalent or overlapping heterogenous schemas.\",\n \"Title: Algebraic query optimisation for database programming languages\\nYear: 1996\\n\\nAbstract: A major challenge still facing the designers and implementors of database programming languages (DBPLs) is that of query optimisation. We investigate algebraic query optimisation techniques for DBPLs in the context of a purely declarative functional language that supports sets as first-class objects. Since the language is computationally complete issues such as non-termination of expressions and construction of infinite data structures can be investigated, whilst its declarative nature allows the issue of side effects to be avoided and a richer set of equivalences to be developed. The language has a well-defined semantics which permits us to reason formally about the properties of expressions, such as their equivalence with other expressions and their termination. The support of a set bulk data type enables much prior work on the optimisation of relational languages to be utilised.In the paper we first give the syntax of our archetypal DBPL and briefly discuss its semantics. We then define a small but powerful algebra of operators over the set data type, provide some key equivalences for expressions in these operators, and list transformation principles for optimising expressions. Along the way, we identify some caveats to well-known equivalences for non-deductive database languages. We next extend our language with two higher level constructs commonly found in functional DBPLs: set comprehensions and functions with known inverses. Some key equivalences for these constructs are provided, as are transformation principles for expressions in them. Finally, we investigate extending our equivalences for the set operators to the analogous operators over bags. Although developed and formally proved in the context of a functional language, our findings are directly applicable to other DBPLs of similar expressiveness.\",\n \"Title: Extraction and evaluation of candidate named entities in search engine queries\\nYear: 2012\\n\\nAbstract: Named Entity Recognition (NER) has recently been applied to search queries, in order to better understand their semantics. We present a novel method for detecting candidate named entities (NEs) using grammar annotation and query segmentation with the aid of top-n snippets from search engine results, and a web n-gram model to accurately identify NE boundaries. We then evaluate this method automatically using DBpedia as a rich data source of NEs, with the aid of a small representative random sample that is manually annotated. Finally, an analysis of the types of named entities that often occur in a query log is conducted, from which a search query driven named entity taxonomy is presented.\",\n \"Title: An Abstract Interpretation Framework for Termination Analysis of Active Rules\\nYear: 1999\\n\\nAbstract: A crucial requirement for active databases is the ability to analyse the behaviour of the active rules. A particularly important type of analysis is termination analysis. We define a framework for modelling the execution of active rules, based on abstract interpretation. Specific methods for termination analysis are modelled as specific approximations within the framework. The correctness of a method can be established by proving two generic requirements provided by the framework. This affords the opportunity to compare and verify existing methods for termination analysis of active rules, and also to develop new ones.\",\n \"Title: Ontology-Assisted Data Transformation and Integration\\nYear: 2008\\n\\nAbstract: Schema-based data transformation and integration (DTI) has been an active research area for some time, while more recent advances in ontologies have led to signiflcant research in ontology-based DTI. These two approaches present some overlaps and some difierences, and in this paper we inves- tigate possible synergies between them. In particular, we show how ontologies can enhance schema-based DTI ap- proaches by providing richer semantics for schema constructs. We also illustrate one way in which schema-based DTI ap- proaches can be used together with ontology-based approaches in a heterogeneous data integration setting.\",\n \"Title: Combining Inheritance and Parametric Polymorphism in a Functional Database Language\\nYear: 1995\\n\\nAbstract: . We consider extending a functional database language tosupport subtyping, inheritance and method overloading. We do so by extendingprevious work on type inference with subtypes for the pure calculusto cater for structured types, ML-style parametric polymorphismand overloaded function definitions. We attach semantics to overloadedfunctions by developing a generalisation of best-fit pattern-matching. Althoughdeveloped for a specific language, our approach is applicable toother...\",\n \"Title: Query performance evaluation of an architecture for fine-grained integration of heterogeneous grid data sources\\nYear: 2010\\n\\nAbstract: Grid data sources may have schema- and data-level conflicts that need to be addressed using data transformation and integration technologies not supported by the current generation of Grid data access and querying middleware. We present an architecture that combines Grid data access and distributed querying with fine-grained data transformation/integration technologies, and the results of a query performance evaluation on this architecture. The performance evaluation indicates that it is indeed feasible to combine such technologies while achieving acceptable query performance. We also discuss the significance of our results for the further development of query performance over heterogeneous Grid data sources.\",\n \"Title: The design of teacher assistance tools in an exploratory learning environment for mathematics generalisation\\nYear: 2010\\n\\nAbstract: The MiGen project is designing and developing an intelligent, exploratory environment to support 11-14-year-old students in their learning of algebraic generalisation. Deployed within the classroom, the system is also providing tools to assist teachers in monitoring students' activities and progress. This paper describes the architectural design of these Teacher Assistance tools and gives a detailed description of one such tool, focussing in particular on the technologies and approaches chosen to implement the necessary functionality given the context of the project.\",\n \"Title: The Conceptual and Architectural Design of a System Supporting Exploratory Learning of Mathematics Generalisation\\nYear: 2009\\n\\nAbstract: The MiGen project is designing and developing an intelligent, exploratory environment to support 11---14-year-old students in their learning of mathematical generalisation. Deployed within the classroom, the system will also provide tools to assist teachers in monitoring students' activities and progress. This paper describes the conceptual and architectural design of the system, and gives a detailed technical explanation of a working proof-of-concept prototype of the architecture, motivating in particular the technologies and approaches chosen to implement the necessary functionality given the context of the project. We also discuss how the prototype will be used as a basis for developing the first full version of the MiGen system, in the context of ongoing knowledge acquisition and analysis within the project's iterative, stakeholder-centred design, development and testing methodology.\",\n \"Title: An event-condition-action language for XML\\nYear: 2002\\n\\nAbstract: XML repositories are now a widespread means for storing and exchanging information on the Web. As these repositories become increasingly used in dynamic applications such as e-commerce, there is a rapidly growing need for a mechanism to incorporate reactive functionality in an XML setting. Event-condition-action (ECA) rules are a technology from active databases and are a natural method for supporting suchfunctionality. ECA rules can be used for activities such as automatically enforcing document constraints, maintaining repository statistics, and facilitating publish/subscribe applications. An important question associated with the use of a ECA rules is how to statically predict their run-time behaviour. In this paper, we define a language for ECA rules on XML repositories. We then investigate methods for analysing the behaviour of a set of ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.\",\n \"Title: Extending a Functional DBPL with ECA-rules\\nYear: 1995\\n\\nAbstract: . We describe how a functional database programming languagecan be extended with transactions and ECA-rules. Fundamentalrequirements of such an extension are that the declarative semanticsof the language not be compromised, that the syntax of the languagenot be disrupted unduly, and that impedance mismatch problems beavoided. We define what we mean by events, conditions and actions anddescribe the semantics of ECA-rules with reference to event detection,parameter-binding, transaction...\",\n \"Title: Abstract Interpretation for Termination Analysis in Functional Active Databases\\nYear: 1999\\n\\nAbstract: An active database consists of a traditional database supplementedby a set of Event-Condition-Action (ECA) rules. One of the key questions for active database designers is that of termination of the ECA rules. The behaviour of the ECA rules may be obscure and their semantics isoften not specified formally.Consequently, developing termination analysis algorithms and proving theircorrectness is a challenging task.In this paper we address this problem for functional active databasesby adopting an abstract interpretation approach.By “functional active databases” we mean active databases whosetransaction execution semantics have been expressed in a purely functionallanguage. Although we demonstrate our techniques for a specific active DBMSwhich supports a functional database programming language interface, thesetechniques are directly applicable to other active DBMSs whose executionsemantics have been specified using a functional or a denotational approach.\",\n \"Title: An Ontology-Based Quality Framework for Data Integration.\\nYear: 2011\\n\\nAbstract: The data integration (DI) process involves multiple users with roles such as administrators, integrators and end-users, each of whom may have requirements which have an impact on the overall quality of an integrated resource. Users' requirements may conflict with each other, and so a quality framework for the DI context has to be capable of representing the variety of such requirements and provide mechanisms to detect and resolve the possible inconsistencies between them. This paper presents a framework for the specification of DI quality criteria and associated user requirements. This is underpinned by a Description Language formalisation with associated reasoning capabilities which enables a DI setting to be tested to identify those elements that are inconsistent with users' requirements. The application of the framework is illustrated with an example showing how it can be used to improve the quality of an integrated resource.\",\n \"Title: Semi-Naive Evaluation for Hyperlog, a Graph-Based Language for Complex Objects\\nYear: 1993\\n\\nAbstract: This paper is concerned with the evaluation of a graph-based declarative language called Hyperlog. Hyperlog is a query- and update-language for a graph-based data model called the Hypernode Model. The single data structure of this model is the hypernode — a graph whose nodes can themselves be graphs. A Hyperlog program is a set of rules whose bodies consist of templates to be matched against a database of graphs. The heads of rules are also templates and indicate the updates to the database to be undertaken for each match of the templates in the body. These updates may include the update of existing graphs or the generation of new graphs.\",\n \"Title: View Generation and Optimisation in the AutoMed Data Integration Framework\\nYear: 2003\\n\\nAbstract: In AutoMed, data integration is based on the use of re- versible sequences of schema transformations. We discuss how views can be generated from these sequences. We also discuss techniques for op- timising the views, flrstly by simplifying the transformation sequences, and secondly by optimising the view deflnitions generated from them.\",\n \"Title: Data access and integration in the ISPIDER proteomics grid\\nYear: 2006\\n\\nAbstract: Grid computing has great potential for supporting the integration of complex, fast changing biological data repositories to enable distributed data analysis. One scenario where Grid computing has such potential is provided by proteomics resources which are rapidly being developed with the emergence of affordable, reliable methods to study the proteome. The protein identifications arising from these methods derive from multiple repositories which need to be integrated to enable uniform access to them. A number of technologies exist which enable these resources to be accessed in a Grid environment, but the independent development of these resources means that significant data integration challenges, such as heterogeneity and schema evolution, have to be met. This paper presents an architecture which supports the combined use of Grid data access (OGSA-DAI), Grid distributed querying (OGSA-DQP) and data integration (AutoMed) software tools to support distributed data analysis. We discuss the application of this architecture for the integration of several autonomous proteomics data resources.\",\n \"Title: Combining approximation and relaxation in semantic web path queries\\nYear: 2010\\n\\nAbstract: We develop query relaxation techniques for regular path queries and combine them with query approximation in order to support flexible querying of RDF data when the user lacks knowledge of its full structure or where the structure is irregular. In such circumstances, it is helpful if the querying system can perform both approximate matching and relaxation of the user's query and can rank the answers according to how closely they match the original query. Our framework incorporates both standard notions of approximation based on edit distance and RDFS-based inference rules. The query language we adopt comprises conjunctions of regular path queries, thus including extensions proposed for SPARQL to allow for querying paths using regular expressions. We provide an incremental query evaluation algorithm which runs in polynomial time and returns answers to the user in ranked order.\",\n \"Title: Combining Data Integration and IE Techniques to Support Partially Structured Data\\nYear: 2008\\n\\nAbstract: A class of applications exists where the information to be stored is partially structured:that is, it consists partly of some structured data sources each conforming to a schema and partly of information left as free text. While investigating the requirements for querying partially structured data, we have encountered several limitations in the currently available approaches and we describe here three new techniques which combine aspects of Information Extraction with data integration in order to better exploit the data in these applications.\",\n \"Title: A Methodology and Architecture Embedding Quality Assessment in Data Integration.\\nYear: 2014\\n\\nAbstract: Data integration aims to combine heterogeneous information sources and to provide interfaces for accessing the integrated resource. Data integration is a collaborative task that may involve many pe...\",\n \"Title: Implementing Flexible Operators for Regular Path Queries.\\nYear: 2015\\n\\nAbstract: Given the heterogeneity of complex graph data on the web, such as RDF linked data,a user wishing to query such data may lack full knowledge of its structure and irregularities.Hence, providing users with flexible querying capabilities can be beneficial. The query language we adopt comprisesconjunctions of regular path queries, thus including extensions proposed for SPARQL 1.1 to allow for querying paths using regular expressions. To this language we add two operators: APPROX, supporting standard notions ofapproximation based on edit distance, and RELAX, which performs query relaxation based on RDFS inference rules.We describe our techniques for implementing the extended language and present a performance study undertaken on two real-world data sets. Our baseline implementation performs competitively with other automaton-based approaches, and we demonstrate empirically how various optimisations can decrease execution times of queries containing APPROX and RELAX, sometimes by orders of magnitude.\",\n \"Title: Flexible Querying for SPARQL.\\nYear: 2014\\n\\nAbstract: Flexible querying techniques can be used to enhance users' access to heterogeneous data sets, such as Linked Open Data. This paper extends SPARQL 1.1 with approximation and relaxation operators that can be applied to regular expressions for querying property paths in order to find more answers than would be returned by the exact form of a user query. We specify the semantics of the extended language and we consider the complexity of query answering with the new operators, showing that both data and query complexity are not impacted by our extensions. We present a query evaluation algorithm that returns results incrementally according to their \\\"distance\\\" from the original query. We have implemented this algorithm and have conducted preliminary trials over the YAGO SPARQL endpoint and the Lehigh University Benchmark, showing promising performance for the language extensions.\",\n \"Title: Mining named entities from search engine query logs\\nYear: 2014\\n\\nAbstract: We present a seed expansion based approach to classify named entities in web search queries. Previous approaches to this classification problem relied on contextual clues in the form of keywords surrounding a named entity in the query. Here we propose an alternative approach in the form of a Bag-of-Context-Words (BoCW) that is used to represent the context words as they appear in the snippets of the top search results for the query. This is particularly useful in the case where the query consists of only the named entity without any context words, since in the previous approaches no context is discovered. In order to construct the BoCW, we employ a novel algorithm, which iteratively expands a Class Vector that is created through expansion by gradually aggregating the BoCWs of similar named entities appearing in other queries. We provide comprehensive experimental evidence using a commercial query log showing that our approach is competitive with existing approaches.\",\n \"Title: Data integration by bi-directional schema transformation rules\\nYear: 2003\\n\\nAbstract: In this paper we describe a new approach to data integration which subsumes the previous approaches of local as view (LAV) and global as view (GAV). Our method, which we term both as view (BAV), is based on the use of reversible schema transformation sequences. We show how LAV and GAV view defl- nitions can be fully derived from BAV schema trans- formation sequences, and how BAV transformation se- quences may be partially derived from LAV or GAV view deflnitions. We also show how BAV supports the evolution of both global and local schemas, and we discuss ongoing implementation of the BAV approach within the AutoMed project.\",\n \"Title: An example of the ESTEST approach to combining unstructured text and structured data\\nYear: 2004\\n\\nAbstract: In this paper, we demonstrate the use of the ESTEST system, which combines the data integration approach with techniques from Information Extraction in order to allow information from ontologies and natural language sources to be integrated with other, semantically related, structured or semi-structured data.\",\n \"Title: Flexible data integration and ontology-based data access to medical records\\nYear: 2008\\n\\nAbstract: The ASSIST project aims to facilitate cervical cancer research by integrating medical records containing both phenotypic and genotypic data, and residing in different medical centres or hospitals. The goal of ASSIST is to enable the evaluation of medical hypotheses and the conduct of association studies in an intuitive manner, thereby allowing medical researchers to identify risk factors that can then be used at the point of care to identify women who are at high risk of developing cervical cancer. This paper presents the current status of the ASSIST medical knowledgebase. In particular, we discuss the challenges faced in constructing the ASSIST integrated resource and in enabling query processing through a domain ontology, and the solutions provided using the AutoMed heterogeneous data integration system. We focus on data cleansing issues, on data integration issues related to integrating relational medical data sources into an independent domain ontology and also on query processing. Of particular interest is the challenge of providing an easily maintainable integrated resource in a setting where the data sources and the domain ontology are developed independently and are therefore both highly likely to evolve over time.\",\n \"Title: Event-Based Awareness Services For P2p Groupware Systems\\nYear: 2015\\n\\nAbstract: P2P systems enable decentralised applications for supporting collaborating groups and communities, where the collaboration may involve both sharing of data and sharing of group processes among group members. In such applications, monitoring and awareness are critical functionalities required for an effective collaboration. However, to date there has been little research into providing generic, application-independent awareness in P2P groupware systems. We present a distributed event-based awareness approach for such systems that provides different forms of awareness through a set of interoperating, low-level awareness services. The user and technical requirements for the approach are motivated with reference to Project-Based Learning in a P2P environment. We describe the implementation of a superpeer P2P network on a Cloud platform and the provision of reliable awareness services (AaaS - Awareness as a Service) from the Cloud. We report on the outcomes of an empirical evaluation of the performance and scalability of the approach.\",\n \"Title: The development of a system for supporting the lifelong learner\\nYear: 2006\\n\\nAbstract: Given the rapidly changing skills needs of 'post-industrial economies', lifelong learning forms an integral part of government policy within the UK and abroad. However, like the UK, most economies are faced with the problem of how to reach those sections of the community that have traditionally not embraced learning and educational opportunities. In this paper, the development and evaluation of a system designed to address this problem is described. The Lifelong Learning in London for All (L4All) project has investigated the concept of 'trails' as a way of organising lifelong learning opportunities. The L4All pilot system combines a set of web services to provide the functionality needed to support this central idea. The development process was outlined, and the findings of an empirical study were used to confirm proof of concept.\",\n \"Title: Learning as immersive experiences: Using the four-dimensional framework for designing and evaluating immersive learning experiences in a virtual world\\nYear: 2010\\n\\nAbstract: Traditional approaches to learning have often focused upon knowledge transfer strategies that have centred on textually-based engagements with learners, and dialogic methods of interaction with tutors. The use of virtual worlds, with text-based, voice-based and a feeling of 'presence' naturally is allowing for more complex social interactions and designed learning experiences and role plays, as well as encouraging learner empowerment through increased interactivity. To unpick these complex social interactions and more interactive designed experiences, this paper considers the use of virtual worlds in relation to structured learning activities for college and lifelong learners. This consideration necessarily has implications upon learning theories adopted and practices taken up, with real implications for tutors and learners alike. Alongside this is the notion of learning as an ongoing set of processes mediated via social interactions and experiential learning circumstances within designed virtual and hybrid spaces. This implies the need for new methodologies for evaluating the efficacy, benefits and challenges of learning in these new ways. Towards this aim, this paper proposes an evaluation methodology for supporting the development of specified learning activities in virtual worlds, based upon inductive methods and augmented by the four-dimensional framework reported in a previous study. The study undertaken aimed to test the efficacy of the proposed evaluation methodology and framework, and to evaluate the broader uses of a virtual world for supporting lifelong learners specifically in their educational choices and career decisions. The paper presents the findings of the study and considers that virtual worlds are reorganising significantly how we relate to the design and delivery of learning. This is opening up a transition in learning predicated upon the notion of learning design through the lens of 'immersive learning experiences' rather than sets of knowledge to be transferred between tutor and learner. The challenges that remain for tutors rest with the design and delivery of these activities and experiences. The approach advocated here builds upon an incremental testing and evaluation of virtual world learning experiences.\",\n \"Title: Efficient regular path query evaluation using path indexes.\\nYear: 2016\\n\\nAbstract: We demonstrate the use of localized path indexes in generating efficient execution plans for regular path queries. This study is motivated by both the practicality of this class of queries and by the current dearth ofscalable solutions for their evaluation. Our proposed solution leverages widely available relational database technology and is often orders of magnitude faster than currently known approaches. We aim in this hands-on demonstration to both highlight the promise of our approach and to stimulate further discussion and study of engineering solutions for this practical yet challenging class of graph queries.\",\n \"Title: Visualisation and Analysis of Students' Interaction Data in Exploratory earning Environments\\nYear: 2015\\n\\nAbstract: Log files from adaptive Exploratory Learning Environments can contain prohibitively large quantities of data for visualisation and analysis. Moreover, it is hard to know in advance what data is required for analytical purposes. Using a microworld for secondary algebra as a case study, we discuss how students' interaction data can be transformed into a data warehouse in order to allow its visualisation and exploration using online analytical processing (OLAP) tools. We also present some additional, more targeted, visualisations of the students' interaction data. We demonstrate the possibilities that these visualisations provide for exploratory data analysis, enabling confirmation or contradiction of expectations that pedagogical experts may have about the system and ultimately providing both empirical evidence and insights for its further development.\",\n \"Title: Scalable Monitoring of Student Interaction Indicators in Exploratory Learning Environments.\\nYear: 2016\\n\\nAbstract: We present and evaluate a web-based architecture for monitoring student-system interaction indicators in Exploratory Learning Environments (ELEs),using as our case study a microworld for secondary school algebra. We discuss the challenging role of teachers in exploratory learning settings and motivate the need for visualisation and notification tools that can assist teachers in focusing their attention across the class and inform teachers' interventions. We present an architecture that can support such Teacher Assistance tools and demonstrate its scalability to allow concurrent usage by thousands of users (students and teachers).\",\n \"Title: Design and evaluation of teacher assistance tools for exploratory learning environments.\\nYear: 2016\\n\\nAbstract: We present our approach to designing and evaluating tools that can assist teachers in classroom settings where students are using Exploratory Learning Environments (ELEs), using as our case study the MiGen system, which targets 1114 year old students' learning of algebra. We discuss the challenging role of teachers in exploratory learning settings and motivate the need for visualisation and notification tools that can assist teachers in focusing their attention across the whole class and inform their interventions. We present the design and evaluation approach followed during the development of MiGen's Teacher Assistance tools, drawing parallels with the recently proposed LATUX workflow but also discussing how we go beyond this to include a large number of teacher participants in our evaluation activities, so as to gain the benefit of different view points. We discuss the results of the evaluations, which show that participants appreciated the capabilities of the tools and were mostly able to use them quickly and accurately.\",\n \"Title: Analysing engagement in an online management programme and implications for course design.\\nYear: 2016\\n\\nAbstract: We analyse engagement and performance data arising from participants' interactions with an in-house LMS at Imperial College London while a cohort of students follow two courses on a new online postgraduate degree in Management. We identify and investigate two main questions relating to the relationships between engagement and performance, drawing recommendations for improved guidelines to inform the design of such courses.\",\n \"Title: Query Rewriting Under Linear Epsilon L Knowledge Bases\\nYear: 2016\\n\\nAbstract: With the adoption of the recent SPARQL 1.1 standard, RDF databases are capable of directly answering more expressive queries than simple conjunctive queries. In this paper we exploit such capabilities to answer conjunctive queries (CQs) under ontologies expressed in the description logic called linear ELlin in, a restricted form of EL. In particular, we show a query answering algorithm that rewrites a given CQ into a conjunctive regular path query (CRPQ) which, evaluated on the given instance, returns the correct answer. Our technique is based on the representation of infinite unions of CQs by non-deterministic finite-state automata. Our results achieve optimal data complexity, as well as producing rewritings straightforwardly implementable in SPARQL 1.1.\",\n \"Title: Approximation and relaxation of semantic web path queries.\\nYear: 2016\\n\\nAbstract: Given the heterogeneity of complex graph data on the web, such as RDF linked data, it is likely that a user wishing to query such data will lack full knowledge of the structure of the data and of its irregularities. Hence, providing flexible querying capabilities that assist users in formulating their information seeking requirements is highly desirable. In this paper we undertake a detailed theoretical investigation of query approximation, query relaxation, and their combination, for this purpose. The query language we adopt comprises conjunctions of regular path queries, thus encompassing recent extensions to SPARQL to allow for querying paths in graphs using regular expressions (SPARQL 1.1). To this language we add standard notions of query approximation based on edit distance, as well as query relaxation based on RDFS inference rules. We show how both of these notions can be integrated into a single theoretical framework and we provide incremental evaluation algorithms that run in polynomial time in the size of the query and the data, returning answers in ranked order of their ‘distance’ from the original query. We also combine for the first time these two disparate notions into a single ‘flex’ operation that simultaneously applies both approximation and relaxation to a query conjunct, providing even greater flexibility for users, but still retaining polynomial time evaluation complexity and the ability to return query answers in ranked order.\",\n \"Title: Similarity-Based Grouping to Support Teachers on Collaborative Activities in an Exploratory Mathematical Microworld.\\nYear: 2017\\n\\nAbstract: This paper describes a computer-based tool that helps teachers group their students for collaborative activities in the context of secondary school math teaching, the challenge being to organize groups of students based on their recent work, so that their collaboration results in meaningful interactions. The complexity of the exploratory learning tasks is such that the teachers would require too l...\",\n \"Title: Design and Evaluation of Adaptive Feedback to Foster ICT Information Processing Skills in Young Adults.\\nYear: 2017\\n\\nAbstract: This paper explores the provision of adaptive hints based on attainment levels in the context of supporting the development of young adults' ICT information processing skills. We describe the design of the LIBE VLE, particularly its personalisation and adaptation features, and a User Study undertaken with young adults at a vocational education centre. Using data collected through the LIBE VLE, we analyse the relationships between learners' accessing of hints, motivation, and performance. Results point to a positive effect of accessing of hints on students' perception of the LIBE VLE and their likelihood of using it again for further learning; and also a positive effect of students' interest in the course subject on their engagement and performance in course activities. These findings have important implications for supporting young adults in developing key competences necessary for integration into the workforce and for fostering self-regulated lifelong learning.\",\n \"Title: Investigations on Path Indexing for Graph Databases.\\nYear: 2016\\n\\nAbstract: Graph databases have become an increasingly popular choice for the management of the massive network data sets arising in many contemporary applications. We investigate the effectiveness of path indexing for accelerating query processing in graph database systems, using as an exemplar the widely used open-source Neo4j graph database. We present a novel path index design which supports efficient ordered access to paths in a graph dataset. Our index is fully persistent and designed for external memory storage and retrieval. We also describe a compression scheme that exploits the limited differences between consecutive keys in the index, as well as a workload-driven approach to indexing. We demonstrate empirically the speed-ups achieved by our implementation, showing that the path index yields query run-times from 2x up to 8000x faster than Neo4j. Empirical evaluation also shows that our scheme leads to smaller indexes than using general-purpose LZ4 compression. The complete stand-alone implementation of our index, as well as supporting tooling such as a bulk-loader, are provided as open source for further research and development.\",\n \"Title: Evaluating Knowledge Anchors in Data Graphs Against Basic Level Objects.\\nYear: 2017\\n\\nAbstract: The growing number of available data graphs in the form of RDF Linked Data enables the development of semantic exploration applications in many domains. Often, the users are not domain experts and are therefore unaware of the complex knowledge structures represented in the data graphs they interact with. This hinders users’ experience and effectiveness. Our research concerns intelligent support to facilitate the exploration of data graphs by users who are not domain experts. We propose a new navigation support approach underpinned by the subsumption theory of meaningful learning, which postulates that new concepts are grasped by starting from familiar concepts which serve as knowledge anchors from where links to new knowledge are made. Our earlier work has developed several metrics and the corresponding algorithms for identifying knowledge anchors in data graphs. In this paper, we assess the performance of these algorithms by considering the user perspective and application context. The paper address the challenge of aligning basic level objects that represent familiar concepts in human cognitive structures with automatically derived knowledge anchors in data graphs. We present a systematic approach that adapts experimental methods from Cognitive Science to derive basic level objects underpinned by a data graph. This is used to evaluate knowledge anchors in data graphs in two application domains - semantic browsing (Music) and semantic search (Careers). The evaluation validates the algorithms, which enables their adoption over different domains and application contexts.\",\n \"Title: Histogram Domain Ordering for Path Selectivity Estimation.\\nYear: 2018\\n\\nAbstract: We aim to improve the accuracy of path selectivity estimation in graph databases by intelligently ordering the domain of a histogram used for estimation. This problem has not, to our knowledge, received adequate attention in the research community. We present a novel framework for the systematic study of path ordering strategies in histogram construction and use. In this framework, we introduce new ordering strategies which we experimentally demonstrate lead to significant improvement of the accuracy of path selectivity estimation over current strategies. These positive results highlight the fundamental role that domain ordering plays in the design of effective histograms for efficient and scalable graph query processing.\",\n \"Title: Using Graph-based Modelling to explore changes in students' affective states during exploratory learning tasks.\\nYear: 2017\\n\\nAbstract: This paper describes how graph-based modelling can be used to explore interactions associated with a change in studentsu0027 affective state when they are working with an exploratory learning environment (ELE). We report on a user study with an ELE that is able to detect studentsu0027 affective states from their interactions and speech. The data collected during the user study was modelled, visualized and queried as a graph. We were interested in exploring if there was a difference between low- and high-performing students in the kinds of interactions that occurred during a change in their affective state. Our findings provide new insights into how students are interacting with the ELE and the effects of the systemu0027s interventions on studentsu0027 affective states.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":92,"string":"92"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13350,"string":"13,350"}}},{"rowIdx":13351,"cells":{"question_id":{"kind":"string","value":"Meiqin Wang"},"question":{"kind":"string","value":"Generate an abstract for the title \"Automatic Search of Bit-Based Division Property for ARX Ciphers and Word-Based Division Property.\" using the following items: Division property, automatic searching, ARX ciphers, SAT method, distinguishers."},"answer":{"kind":"string","value":"Division property is a generalized integral property proposed by Todo at Eurocrypt 2015. Previous tools for automatic searching are mainly based on the Mixed Integer Linear Programming (MILP) method and trace the division property propagation at the bit level. In this paper, we propose automatic tools to detect ARX ciphers' division property at the bit level and some specific ciphers' division property at the word level. For ARX ciphers, we construct the automatic searching tool relying on Boolean Satisfiability Problem (SAT) instead of MILP, since SAT method is more suitable in the search of ARX ciphers' differential/linear characteristics. The propagation of division property is translated into a system of logical equations in Conjunctive Normal Form (CNF). Some logical equations can be dynamically adjusted according to different initial division properties and stopping rule, while the others corresponding to r-round propagations remain the same. Moreover, our approach can efficiently identify some optimized distinguishers with lower data complexity. As a result, we obtain a 17-round distinguisher for SHACAL-2, which gains four more rounds than previous work, and an 8-round distinguisher for LEA, which covers one more round than the former one. For word-based division property, we develop the automatic search based on Satisfiability Modulo Theories (SMT), which is a generalization of SAT. We model division property propagations of basic operations and S-boxes by logical formulas, and turn the searching problem into an SMT problem. With some available solvers, we achieve some new distinguishers. For CLEFIA, 10-round distinguishers are obtained, which cover one more round than the previous work. For the internal block cipher of Whirlpool, the data complexities of 4/5-round distinguishers are improved. For Rijndael-192 and Rijndael-256, 6-round distinguishers are presented, which attain two more rounds than the published ones. Besides, the integral attacks for CLEFIA are improved by one round with the newly obtained distinguishers."},"correct_answer":{"kind":"string","value":"Division property is a generalized integral property proposed by Todo at Eurocrypt 2015. Previous tools for automatic searching are mainly based on the Mixed Integer Linear Programming (MILP) method and trace the division property propagation at the bit level. In this paper, we propose automatic tools to detect ARX ciphers' division property at the bit level and some specific ciphers' division property at the word level. For ARX ciphers, we construct the automatic searching tool relying on Boolean Satisfiability Problem (SAT) instead of MILP, since SAT method is more suitable in the search of ARX ciphers' differential/linear characteristics. The propagation of division property is translated into a system of logical equations in Conjunctive Normal Form (CNF). Some logical equations can be dynamically adjusted according to different initial division properties and stopping rule, while the others corresponding to r-round propagations remain the same. Moreover, our approach can efficiently identify some optimized distinguishers with lower data complexity. As a result, we obtain a 17-round distinguisher for SHACAL-2, which gains four more rounds than previous work, and an 8-round distinguisher for LEA, which covers one more round than the former one. For word-based division property, we develop the automatic search based on Satisfiability Modulo Theories (SMT), which is a generalization of SAT. We model division property propagations of basic operations and S-boxes by logical formulas, and turn the searching problem into an SMT problem. With some available solvers, we achieve some new distinguishers. For CLEFIA, 10-round distinguishers are obtained, which cover one more round than the previous work. For the internal block cipher of Whirlpool, the data complexities of 4/5-round distinguishers are improved. For Rijndael-192 and Rijndael-256, 6-round distinguishers are presented, which attain two more rounds than the published ones. Besides, the integral attacks for CLEFIA are improved by one round with the newly obtained distinguishers."},"documents":{"kind":"list like","value":["Title: Integral and multidimensional linear distinguishers with correlation zero\nYear: 2012\n\nAbstract: Zero-correlation cryptanalysis uses linear approximations holding with probability exactly 1/2. In this paper, we reveal fundamental links of zero-correlation distinguishers to integral distinguishers and multidimensional linear distinguishers. We show that an integral implies zero-correlation linear approximations and that a zero-correlation linear distinguisher is actually a special case of multidimensional linear distinguishers. These observations provide new insight into zero-correlation cryptanalysis which is illustrated by attacking a Skipjack variant and round-reduced CAST-256 without weak key assumptions.","Title: Difierential Cryptanalysis of PRESENT\nYear: 2007\n\nAbstract: PRESENT is proposed by A.Bogdanov et al. in CHES 2007 for extremely constrained environments such as RFID tags and sensor networks. In this paper, we flnd out the difierential characteristics for r-round(5 • r • 15), then give the difierential cryptanalysis on reduced-round variants of PRESENT. We attack 16-round PRESENT using 264 chosen plaintexts, 232 6-bit counters, and 265 memory accesses.","Title: Zero-Correlation Linear Cryptanalysis with FFT and Improved Attacks on ISO Standards Camellia and CLEFIA.\nYear: 2013\n\nAbstract: Zero-correlation linear cryptanalysis is based on the linear approximations with correlation exactly zero, which essentially generalizes the integral property, and has already been applied to several block ciphers - among others, yielding best known attacks to date on round-reduced TEA and CAST-256 as published in FSE'12 and ASI-ACRYPT'12, respectively. In this paper, we use the FFT (Fast Fourier Transform) technique to speed up the zero-correlation cryptanalysis. First, this allows us to improve upon the state-of-the-art cryptanalysis for the ISO/IEC standard and CRYPTREC-portfolio cipher Camellia. Namely, we present zero-correlation attacks on 11-round Camellia-128 and 12-round Camellia192 with FL/FL-1 and whitening key starting from the first round, which is an improvement in the number of attacked rounds in both cases. Moreover, we provide multidimensional zero-correlation cryptanalysis of 14-round CLEFIA-192 and 15-round CLEFIA-256 that are attacks on the highest numbers of rounds in the classical single-key setting, respectively, with improvements in memory complexity.","Title: Related-Key Impossible Differential Attack on Reduced-Round LBlock.\nYear: 2014\n\nAbstract: LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16-round related-key impossible differentials of LBlock, which are better than the 15-round related-key impossible differentials used in the previous attack. Based on these 16-round related-key impossible differentials, we can attack 23 rounds of LBlock while the previous related-key impossible differential attacks could only work on 22-round LBlock. This makes our attack on LBlock the best attack in terms of the number of attacked rounds. ? 2014 Springer Science+Business Media New York & Science Press, China.","Title: Side Channel Cube Attack on PRESENT\nYear: 2009\n\nAbstract: As an ultra-lightweight block cipher, PRESENT is presented by A. Bogdanov et al. in CHES 2007. In this paper, we detect the non-random properties in the first four rounds of PRESENT based on cube attack proposed by Shamir et al. By analyzing the features of the S-box and pLayer, we give the side channel cube attack on PRESENT. If any output bit of the third round is leaked, we can recover the total 80-bit key. Especially, for the leaked bit 1, bit 2 or bit 3 of the output bits in the third round, we can also recover 80-bit key with lower computing complexity compared to other leaked bits, and our attack requires 215 chosen plaintexts and 232 31-round PRESENT encryptions.","Title: Differential-algebraic cryptanalysis of reduced-round of Serpent-256.\nYear: 2010\n\nAbstract: Differential cryptanalysis is a general cryptanalytic tool that makes use of differentials over some rounds of a cipher, combined\n with some key bit guesses of one or two rounds. This paper introduces a new cryptanalysis strategy of block ciphers named\n differential-algebraic cryptanalysis. The idea of differential-algebraic cryptanalysis is to find a differential with high\n probability and build the multivariable system equations for the last few rounds. The subkey values of the last few rounds\n can be obtained by filtering the solutions of system equations instead of guessing all possible subkey values. We use the\n differential-algebraic cryptanalysis to break 8-round Serpent-256. Our attack can recover the 256-bit key with 283 chosen plaintexts, 2180.4 8-round Serpent-256 encryptions and 2176.7 bytes memory. Compared with the previous differential cryptanalysis results, both the data complexity and the time complexity\n are reduced, but the memory requirements are increased. The time complexity and the memory requirements are very close, and\n a time-memory tradeoff is exploited.","Title: Practical attack on the full MMB block cipher\nYear: 2011\n\nAbstract: Modular Multiplication based Block Cipher (MMB) is a block cipher designed by Daemen et al. as an alternative to the IDEA block cipher. In this paper, we give a practical sandwich attack on MMB with adaptively chosen plaintexts and ciphertexts. By constructing a 5-round sandwich distinguisher of the full 6-round MMB with probability 1, we recover the main key of MMB with text complexity 240 and time complexity 240 MMB encryptions. We also present a chosen plaintexts attack on the full MMB by employing the rectangle-like sandwich attack, which the complexity is 266.5 texts, 266.5 MMB encryptions and 270.5 bytes of memory. In addition, we introduce an improved differential attack on MMB with 296 chosen plaintexts, 296 encryptions and 266 bytes of memory. Especially, even if MMB is extended to 7 rounds, the improved differential attack is applicable with the same complexity as that of the full MMB.","Title: Impossible differential cryptanalysis of the lightweight block ciphers TEA, XTEA and HIGHT\nYear: 2012\n\nAbstract: TEA, XTEA and HIGHT are lightweight block ciphers with 64-bit block sizes and 128-bit keys. The round functions of the three ciphers are based on the simple operations XOR, modular addition and shift/rotation. TEA and XTEA are Feistel ciphers with 64 rounds designed by Needham and Wheeler, where XTEA is a successor of TEA, which was proposed by the same authors as an enhanced version of TEA. HIGHT, which is designed by Hong et al., is a generalized Feistel cipher with 32 rounds. These block ciphers are simple and easy to implement but their diffusion is slow, which allows us to find some impossible properties. This paper proposes a method to identify the impossible differentials for TEA and XTEA by using the weak diffusion, where the impossible differential comes from a bit contradiction. Our method finds a 14-round impossible differential of XTEA and a 13-round impossible differential of TEA, which result in impossible differential attacks on 23-round XTEA and 17-round TEA, respectively. These attacks significantly improve the previous impossible differential attacks on 14-round XTEA and 11-round TEA given by Moon et al. from FSE 2002. For HIGHT, we improve the 26-round impossible differential attack proposed by Özen et al.; an impossible differential attack on 27-round HIGHT that is slightly faster than the exhaustive search is also given.","Title: New Distinguishing Attack on MAC Using Secret-Prefix Method\nYear: 2009\n\nAbstract: This paper presents a new distinguisher which can be applied to secret-prefix MACs with the message length prepended to the message before hashing. The new distinguisher makes use of a special truncated differential path with high probability to distinguish an inner near-collision in the first round. Once the inner near-collision is detected, we can recognize an instantiated MAC from a MAC with a random function. The complexity for distinguishing the MAC with 43-step reduced SHA-1 is 2124.5 queries. For the MAC with 61-step SHA-1, the complexity is 2154.5 queries. The success probability is 0.70 for both.","Title: Key Difference Invariant Bias in Block Ciphers\nYear: 2013\n\nAbstract: In this paper, we reveal a fundamental property of block ciphers: There can exist linear approximations such that their biases ε are deterministically invariant under key difference. This behaviour is highly unlikely to occur in idealized ciphers but persists, for instance, in 5-round AES. Interestingly, the property of key difference invariant bias is independent of the bias value ε itself and only depends on the form of linear characteristics comprising the linear approximation in question as well as on the key schedule of the cipher. We propose a statistical distinguisher for this property and turn it into an key recovery. As an illustration, we apply our novel cryptanalytic technique to mount related-key attacks on two recent block ciphers -- LBlock and TWINE. In these cases, we break 2 and 3 more rounds, respectively, than the best previous attacks.","Title: Differential cryptanalysis of reduced-round ICEBERG\nYear: 2012\n\nAbstract: ICEBERG is proposed by Standaert et al. in FSE 2004 for reconfigurable hardware implementations. It uses 64-bit block size and 128-bit key and the round number is 16. Specially, it is a SPN block cipher and all components are involutional and allow very efficient combinations of encryption/decryption. In this paper, we propose an elaborate method to identify the 6-round differentials and present the differential attack on 7-round ICEBERG with 257 chosen plaintexts and 290.28 7-round encryptions. Then we use multiple differentials to attack 8-round ICEBERG with 263 chosen plaintexts and 296 8-round encryptions. The previous linear cryptanalysis can only attack 7-round ICEBERG with the whole codebook. It means that ICEBERG is more resistant to linear cryptanalysis than differential cryptanalysis. Although our attack cannot threat ICEBERG, we give the best attack for ICEBERG published to date and our elaborate method to identify multiple differential can be used for other similar block ciphers.","Title: Differential cryptanalysis of reduced-round PRESENT\nYear: 2008\n\nAbstract: PRESENT is proposed by A. Bogdanov et al. in CHES 2007 for extremely constrained environments such as RFID tags and sensor networks. In this paper, we present the differential characteristics for r-round(5 ≤ r ≤ 15), then give the differential cryptanalysis on reduced-round variants of PRESENT. We attack 16-round PRESENT using 264 chosen plaintexts, 232 6-bit counters, and 264 memory accesses.","Title: How to search linear approximation for large non-surjective S-box\nYear: 2011\n\nAbstract: Linear cryptanalysis is a general form of cryptanalysis based on identifying the linear approximations of a cipher. It is one of the two most widely used attacks on block ciphers. In order to resist the differential cryptanalysis, the S-box with large output bit number is applied in block cipher, for example CAST-128 and CAST-256 use the 8 × 32 S-boxes. In addition, the S-boxes are often constructed based on bent functions to resist the linear cryptanalysis and the S-boxes are non-surjective mapping. Therefore, for the large non-surjective S-box, to identify the best linear approximation with zero input mask and nonzero output mask is difficult due to the unaccepted computation time. In this paper, we will give an efficient computing method to find such best linear approximations for the non-surjective large S-boxes using parallel computation in practical time. This computing method can help to estimate the resistant property for some kind of linear cryptanalysis of block ciphers with this kind of S-box.","Title: Zero correlation linear cryptanalysis with reduced data complexity\nYear: 2012\n\nAbstract: Zero correlation linear cryptanalysis is a novel key recovery technique for block ciphers proposed in [5]. It is based on linear approximations with probability of exactly 1/2 (which corresponds to the zero correlation). Some block ciphers turn out to have multiple linear approximations with correlation zero for each key over a considerable number of rounds. Zero correlation linear cryptanalysis is the counterpart of impossible differential cryptanalysis in the domain of linear cryptanalysis, though having many technical distinctions and sometimes resulting in stronger attacks. In this paper, we propose a statistical technique to significantly reduce the data complexity using the high number of zero correlation linear approximations available. We also identify zero correlation linear approximations for 14 and 15 rounds of TEA and XTEA. Those result in key-recovery attacks for 21-round TEA and 25-round XTEA, while requiring less data than the full code book. In the single secret key setting, these are structural attacks breaking the highest number of rounds for both ciphers. The findings of this paper demonstrate that the prohibitive data complexity requirements are not inherent in the zero correlation linear cryptanalysis and can be overcome. Moreover, our results suggest that zero correlation linear cryptanalysis can actually break more rounds than the best known impossible differential cryptanalysis does for relevant block ciphers. This might make a security re-evaluation of some ciphers necessary in the view of the new attack.","Title: A hybrid approach for authenticating MPEG-2 streaming data\nYear: 2007\n\nAbstract: There are two main approaches for authenticating digital streams, namely the tree chaining [1] and the hash chaining [2,3]. Both approaches have their disadvantages. Hash chaining is superior for low communication overhead, however, it is not resilient to packet loss and it has a longer verification delay. On the other hand, tree chaining is more robust even if packet loss occurs and with shorter verification delay, but the communication overhead is too high to be tolerable, especially in online applications. In this paper, we try to combine the two techniques and propose a hybrid scheme for authenticating MPEG-2 streaming data, which are still used by real application systems, by taking advantage of the characteristics of MPEG frames. The hybrid approach is shown to be more effective as compared to the other two approaches.","Title: Multidimensional zero-correlation attacks on lightweight block cipher HIGHT: Improved cryptanalysis of an ISO standard\nYear: 2014\n\nAbstract: HIGHT is a block cipher designed in Korea with the involvement of Korea Information Security Agency. It was proposed at CHES 2006 for usage in lightweight applications such as sensor networks and RFID tags. Lately, it has been adopted as ISO standard. Though there is a great deal of cryptanalytic results on HIGHT, its security evaluation against the recent zero-correlation linear attacks is still lacking. At the same time, the Feistel-type structure of HIGHT suggests that it might be susceptible to this type of cryptanalysis. In this paper, we aim to bridge this gap. We identify zero-correlation linear approximations over 16 rounds of HIGHT. Based upon those, we attack 27-round HIGHT (round 4 to round 30) with improved time complexity and practical memory requirements. This attack of ours is the best result on HIGHT to date in the classical single-key setting. We also provide the first attack on 26-round HIGHT (round 4 to round 29) with the full whitening key.","Title: On the (In)Equivalence of Impossible Differential and Zero-Correlation Distinguishers for Feistel- and Skipjack-Type Ciphers.\nYear: 2014\n\nAbstract: For many word-oriented block ciphers, impossible differential (ID) and zero-correlation linear (ZC) cryptanalyses are among the most powerful attacks. Whereas ID cryptanalysis makes use of differentials which never occur, the ZC cryptanalysis relies on linear approximations with correlations equal to zero. While the key recovery parts of ID and ZC attacks may differ and are often specific to the target cipher, the underlying distinguishing properties frequently cover the same number of rounds. However, in some cases, the discrepancy between the best known IDs and ZC approximations is rather significant. At EUROCRYPT'13, a link between these two distinguishers has been presented. However, though being independent of the underling structure of the cipher, it is usually not useful for most known ID or ZC distinguishers. So despite the relevance of those attacks, the question of their equivalence or inequivalence has not been formally addressed so far in a constructive practical way. In this paper, we aim to bridge this gap in the understanding of the links between the ID and ZC properties. We tackle this problem at the example of two wide classes of ciphers, namely, Feistel- and Skipjack-type ciphers. As our major contribution, for those ciphers, we derive conditions for impossible differentials and zero-correlation approximations to cover the same number of rounds. Using the conditions, we prove an equivalence between ID and ZC distinguishers for type-I and type-II Feistel- type ciphers, for Rule-A and Rule-B Skipjack-type ciphers, as well as for TWINE and LBlock. Moreover, we show this equivalence for the Extended Generalised Feistel construction presented at SAC'13. We also use our theoretical results to argue for an inequivalence between ID and ZC distinguishers for a range of Skipjack-type ciphers.","Title: Cryptanalysis of the Full MMB Block Cipher\nYear: 2009\n\nAbstract: The block cipher MMB was designed by Daemen, Govaerts and Vandewalle, in 1993, as an alternative to the IDEA block cipher. We exploit and describe unusual properties of the modular multiplication in ${\\mathbb Z}_{2^{32}-1}$, which lead to a differential attack on the full 6-round MMB cipher (both versions 1.0 and 2.0). Further contributions of this paper include detailed square and linear cryptanalysis of MMB. Concerning differential cryptanalysis (DC), we can break the full MMB with 2118 chosen plaintexts, 295.91 6-round MMB encryptions and 264 counters, effectively bypassing the cipher's countermeasures against DC. For the square attack, we can recover the 128-bit user key for 4-round MMB with 234 chosen plaintexts, 2126.32 4-round encryptions and 264 memory blocks. Concerning linear cryptanalysis, we present a key-recovery attack on 3-round MMB requiring 2114.56 known-plaintexts and 2126 encryptions. Moreover, we detail a ciphertext-only attack on 2-round MMB using 293.6 ciphertexts and 293.6 parity computations. These attacks do not depend on weak-key or weak-subkey assumptions, and are thus independent of the key schedule algorithm.","Title: Linear (Hull) and Algebraic Cryptanalysis of the Block Cipher PRESENT\nYear: 2009\n\nAbstract: The contributions of this paper include the first linear hull and a revisit of the algebraic cryptanalysis of reduced-round variants of the block cipher PRESENT, under known-plaintext and ciphertext-only settings. We introduce a pure algebraic cryptanalysis of 5-round PRESENT and in one of our attacks we recover half of the bits of the key in less than three minutes using an ordinary desktop PC. The PRESENT block cipher is a design by Bogdanov et al. , announced in CHES 2007 and aimed at RFID tags and sensor networks. For our linear attacks, we can attack 25-round PRESENT with the whole code book, 296.68 25-round PRESENT encryptions, 240 blocks of memory and 0.61 success rate. Further we can extend the linear attack to 26-round with small success rate. As a further contribution of this paper we computed linear hulls in practice for the original PRESENT cipher, which corroborated and even improved on the predicted bias (and the corresponding attack complexities) of conventional linear relations based on a single linear trail.","Title: A model for structure attacks, with applications to PRESENT and serpent\nYear: 2012\n\nAbstract: As a classic cryptanalytic method for block ciphers, hash functions and stream ciphers, many extensions and refinements of differential cryptanalysis have been developed. In this paper, we focus on the use of so-called structures in differential attacks, i.e. the use of multiple input and one output difference. We give a general model and complexity analysis for structure attacks and show how to choose the set of differentials to minimize the time and data complexities. Being a subclass of multiple differential attacks in general, structure attacks can also be analyzed in the model of Blondeau et al. from FSE 2011. In this very general model, a restrictive condition on the set of input differences is required for the complexity analysis. We demonstrate that in our dedicated model for structure attacks, this condition can be relaxed, which allows us to consider a wider range of differentials. Finally, we point out an inconsistency in the FSE 2011 attack on 18 rounds of the block cipher PRESENT and use our model for structure attacks to attack 18-round PRESENT and improve the previous structure attacks on 7-round and 8-round Serpent. To the best of our knowledge, those attacks are the best known differential attacks on these two block ciphers.","Title: New Linear Cryptanalytic Results of Reduced-Round of CAST-128 and CAST-256\nYear: 2008\n\nAbstract: This paper presents a linear cryptanalysis for reduced round variants of CAST-128 and CAST-256 block ciphers. Compared with the linear relation of round function with the bias 2驴 17 by J. Nakahara et al., we found the more heavily biased linear approximations for 3 round functions and the highest one is 2驴 12.91. We can mount the known-plaintext attack on 6-round CAST-128 and the ciphertext-only attack on 4-round CAST-128. Moreover the known-plaintext attack on 24-round CAST-256 with key size 192 and 256 bits has been given, and the ciphertext-only attack on 21-round CAST-256 with key size 192 and 256 bits can be performed. At the same time, we also present the attack on 18-round CAST-256 with key size 128 bits.","Title: Algebraic techniques in differential cryptanalysis revisited\nYear: 2011\n\nAbstract: At FSE 2009, Albrecht et al. proposed a new cryptanalytic method that combines algebraic and differential cryptanalysis. They introduced three new attacks, namely Attack A, Attack B and Attack C. For Attack A, they explain that the time complexity is difficult to determine. The goal of Attacks B and C is to filter out wrong pairs and then recover the key. In this paper, we show that Attack C does not provide an advantage over differential cryptanalysis for typical block ciphers, because it cannot be used to filter out any wrong pairs that satisfy the ciphertext differences. Furthermore, we explain why Attack B provides no advantage over differential cryptanalysis for PRESENT. We verify our results for PRESENT experimentally, using both PolyBoRi and MiniSat. Our work helps to understand which equations are important in the differential-algebraic attack. Based on our findings, we present two new differential-algebraic attacks. Using the first method, our attack on 15-round PRESENT-80 requires 259 chosen plaintexts and has a worstcase time complexity of 273.79 equivalent encryptions. Our new attack on 14-round PRESENT-128 requires 255 chosen plaintexts and has a worstcase time complexity of 2112.83 equivalent encryptions. Although these attacks have a higher time complexity than the differential attacks, their data complexity is lower.","Title: New Differential Cryptanalytic Results For Reduced-Round Cast-128\nYear: 2010\n\nAbstract: CAST 128 is a block cipher used in a number of products notably as the default cipher in some versions of GPG and PGP It has been approved for Canadian government use by the Communications Security Establishment Haruki Seki et al found 2 round differential characteristics and they can attack 5 round CAST 128 In this paper we studied the prop ernes of round functions F-1 and F-3 in CAST 128 and identified differential characteristics for F-1 round function and F-3 round function So we identified a 6 round differential characteristic with probability 2(-53) under 2(-23) (8) of the total key space Then based on 6 round differential characteristic we can attack 8 round CAST 128 with key sizes greater than or equal to 72 bits and 9 round CAST 128 with key sizes greater than or equal to 104 bits We give the summary of attacks on reduced round CAST 128 in Table 10","Title: New impossible differential attack on SAFER+ and SAFER ++\nYear: 2012\n\nAbstract: SAFER+ was a candidate block cipher for AES with 128-bit block size and a variable key sizes of 128, 192 or 256 bits. Bluetooth uses customized versions of SAFER+ for security. The numbers of rounds for SAFER+ with key sizes of 128, 192 and 256 are 8, 12 and 16, respectively. SAFER++, a variant of SAFER+, was among the cryptographic primitives selected for the second phase of the NESSIE project. The block size is 128 bits and the key size can take either 128 or 256 bits. The number of rounds for SAFER++ is 7 for keys of 128 bits, and 10 for keys of 256 bits. Both ciphers use PHT as their linear transformation. In this paper, we take advantage of properties of PHT and S-boxes to identify 3.75-round impossible differentials for SAFER++ and 2.75-round impossible differentials for SAFER+, which result in impossible differential attacks on 4-round SAFER+/128(256), 5-round SAFER++/128 and 5.5-round SAFER++/256. Our attacks significantly improve previously known impossible differential attacks on 3.75-round SAFER +/128(256) and SAFER++/128(256). Our attacks on SAFER +/128(256) and SAFER++/128(256) represent the best currently known attack in terms of the number of rounds. © 2013 Springer-Verlag.","Title: Constructing Mixed-integer Programming Models whose Feasible Region is Exactly the Set of All Valid Differential Characteristics of SIMON.\nYear: 2015\n\nAbstract: In IACR ePrint 2014/747, a method for constructing mixed- integer linear programming (MILP) models whose feasible regions are exactly the sets of all possible dierential (or linear) characteristics for a wide range of block ciphers is presented. These models can be used to search for or enumerate dierential","Title: Equivalent Key Recovery Attacks Against HMAC and NMAC with Whirlpool Reduced to 7 Rounds.\nYear: 2015\n\nAbstract: A main contribution of this paper is an improved analysis against HMAC instantiating with reduced Whirlpool. It recovers equivalent keys, which are often denoted as K-in and K-out, of HMAC with 7-round Whirlpool, while the previous best attack can work only for 6 rounds. Our approach is applying the meet-in-the-middle (MITM) attack on AES to recover MAC keys of Whirlpool. Several techniques are proposed to bypass different attack scenarios between a block cipher and a MAC, e.g., the chosen plaintext model of the MITM attacks on AES cannot be used for HMAC-Whirlpool. Besides, a larger state size and different key schedule designs of Whirlpool leave us a lot of room to study. As a result, equivalent keys of HMAC with 7-round Whirlpool are recovered with a complexity of (Data, Time, Memory) = (2(481.7), 2(482.3), 2(481)).","Title: Improved Linear Cryptanalysis of CAST-256.\nYear: 2014\n\nAbstract: CAST-256, a first-round AES (Advanced Encryption Standard) candidate, is designed based on CAST-128. It is a 48-round Generalized-Feistel-Network cipher with 128-bit block accepting 128, 160, 192, 224 or 256 bits keys. Its S-boxes are non-surjective with 8-bit input and 32-bit output. Wang et al. identified a 21-round linear approximation and gave a key recovery attack on 24-round CAST-256. In ASIACRYPT 2012, Bogdanov et al. presented the multidimensional zero-correlation linear cryptanalysis of 28 rounds of CAST-256. By observing the property of the concatenation of forward quad-round and reverse quad-round and choosing the proper active round function, we construct a linear approximation of 26-round CAST-256 and recover partial key information on 32 rounds of CAST-256. Our result is the best attack according to the number of rounds for CAST-256 without weak-key assumption so far.","Title: Integral Zero-Correlation Distinguisher For Arx Block Cipher, With Application To Shacal-2\nYear: 2014\n\nAbstract: At ASIACRYPT' 12, Bogdanov et al. revealed the identity of integral distinguishers and zero-correlation linear approximations where the mask consists of two parts: one part should take any non-zero value and the other part should be fixed to zero. For zero-correlation linear approximations of some ARX block ciphers, one bit of input mask usually is fixed to one, which do not conform to zero-correlation linear approximations considered by Bogdanov et al.. Can they also be converted to an integral distinguisher? In this paper, we show that such zero-correlation linear approximations can be transformed to an integral distinguisher too. As an application, we give the attack on SHACAL-2 which is one of the four selected block ciphers by NESSIE. Namely, a attack on 32-round SHACAL-2 is reported. As an integral attack, our attack is much better than the previous integral attack on 28-round SHACAL-2 in terms of the number of rounds. In the classical single-key setting, our attack could break as many rounds as the previous best attack, but with significant improvements in data complexity and memory complexity.","Title: Integrals go Statistical: Cryptanalysis of Full Skipjack Variants.\nYear: 2016\n\nAbstract: Integral attacks form a powerful class of cryptanalytic techniques that have been widely used in the security analysis of block ciphers. The integral distinguishers are based on balanced properties holding with probability one. To obtain a distinguisher covering more rounds, an attacker will normally increase the data complexity by iterating through more plaintexts with a given structure under the strict limitation of the full codebook. On the other hand, an integral property can only be deterministically verified if the plaintexts cover all possible values of a bit selection. These circumstances have somehow restrained the applications of integral cryptanalysis. In this paper, we aim to address these limitations and propose a novel statistical integral distinguisher where only a part of value sets for these input bit selections are taken into consideration instead of all possible values. This enables us to achieve significantly lower data complexities for our statistical integral distinguisher as compared to those of traditional integral distinguisher. As an illustration, we successfully attack the full-round Skipjack-BABABABA for the first time, which is the variant of NSA's Skipjack block cipher.","Title: Linear cryptanalysis of reduced-round SPECK\nYear: 2016\n\nAbstract: SPECK is a family of lightweight block ciphers which was proposed by United States National Security Agency and designed for optimal performance in software. The paper gives the security of SPECK against linear cryptanalysis and introduces 9, 10, 12, 15 and 16 rounds linear approximations on SPECK for block sizes of 32, 48, 64, 96 and 128 bits, respectively. Partial linear mask table is used to speed up the search progress rather than the linear mask table. Using the structure of red-black tree to store the pLMT, we deduce the search time. Combining the Segment Searching with branch-and-bound method, the search time is further reduced. For 48-, 96- and 128-bit version the lengths of the linear approximations are 1, 9 and 10 rounds longer than the previous linear cryptanalytic. For SPECK64 the correlation of the linear approximation is twice as much as the previous linear cryptanalytic. As a result, we improve the previous linear cryptanalysis and gain more obvious advantage for block lengths of 96 and 128 bits. Especially, in aspect of SPECK96/144, SPECK128/192 and SPECK128/256 we can attack the same rounds as the best previous attacks. A new search method for linear approximations of the SPECK family.The best known linear approximations of the SPECK family.The best Linear attack on SPECK96 and SPECK128.The same round numbers on SPECK96 and SPECK128 as the best key recovery attack.","Title: New Impossible Differential Attack On Safer Block Cipher Family\nYear: 2015\n\nAbstract: SAFER block cipher family consists of SAFER K, SAFER SK, SAFER+ and SAFER++. As the first proposed block cipher of them, SAFER K is strengthened by SAFER SK with improved key schedule. SAFER+ is designed as an AES candidate and Bluetooth uses a customized version of it for security. SAFER++, a variant of SAFER+, is among the cryptographic primitives selected for the second phase of the NESSIE project. In this paper, we take advantage of properties of the linear transformation and S-boxes to identify new impossible differentials for SAFER SK, SAFER+, and SAFER++. Moreover, we give the impossible differential attacks on 4-round SAFER SK/128 and 4-round SAFER+/128(256), 5-round SAFER++/128 and 5.5-round SAFER++/256. Our attacks significantly improve previously known impossible differential attacks on them. Specifically, our attacks on SAFER+ are the best attack in terms of number of rounds.","Title: Extending the Applicability of the Mixed-Integer Programming Technique in Automatic Differential Cryptanalysis\nYear: 2015\n\nAbstract: We focus on extending the applicability of the mixed-integer programming MIP based method in differential cryptanalysis such that more work can be done automatically. Firstly, we show how to use the MIP-based technique to obtain almost all high probability 2-round iterative related-key differential characteristics of PRIDE a block cipher proposed in CRYPTO 2014 automatically by treating the $$g_i^{j}\\\\cdot $$gijï¾ź function with a special kind of modulo addition operations in the key schedule algorithm of PRIDE as an $$8 \\\\times 8$$8×8 S-box and partially modelling its differential behavior with linear inequalities. Note that some of the characteristics presented in this paper has not been found before, and all the characteristics we found can be used to attack the full-round PRIDE in the related-key model. Secondly, we show how to construct MIP models whose feasible regions are exactly the sets of all possible differential characteristics of SIMON a family of lightweight block ciphers designed by the U.S. National Security Agency. With this method, there is no need to filter out invalid characteristics due to the dependent inputs of the AND operations. Finally, we present an MIP-based method which can be used to automatically analyze how the differences at the beginning and end of a differential distinguisher propagate upwards and downward. Note that how the differences at the ends of a differential distinguisher propagate, together with the probability of the differential distinguisher, determine how many outer rounds can be added to the distinguisher, which key bits can be recovered without exhaustive search, and how to identify wrong pairs in the filtering process. We think this work serves to further strengthens the position of the MIP as a promising tool in automatic differential cryptanalysis.","Title: MILP-Based Automatic Search Algorithms for Differential and Linear Trails for Speck.\nYear: 2016\n\nAbstract: In recent years, Mixed Integer Linear Programming MILP has been successfully applied in searching for differential characteristics and linear approximations in block ciphers and has produced the significant results for some ciphers such as SIMON a family of lightweight and hardware-optimized block ciphers designed by NSA etc. However, in the literature, the MILP-based automatic search algorithm for differential characteristics and linear approximations is still infeasible for block ciphers such as ARX constructions. In this paper, we propose an MILP-based method for automatic search for differential characteristics and linear approximations in ARX ciphers. By researching the properties of differential characteristic and linear approximation of modular addition in ARX ciphers, we present a method to describe the differential characteristic and linear approximation with linear inequalities under the assumptions of independent inputs to the modular addition and independent rounds. We use this representation as an input to the publicly available MILP optimizer Gurobi to search for differential characteristics and linear approximations for ARX ciphers. As an illustration, we apply our method to Speck, a family of lightweight and software-optimized block ciphers designed by NSA, which results in the improved differential characteristics and linear approximations compared with the existing ones. Moreover, we provide the improved differential attacks on Speck48, Speck64, Speck96 and Speck128, which are the best attacks on them in terms of the number of rounds.","Title: Improved Zero-Correlation Cryptanalysis on SIMON.\nYear: 2015\n\nAbstract: SIMON is a family of lightweight block ciphers publicly released by the NSA. Up to now, there have been many cryptanalytic results on it by means of differential, linear, impossible differential, integral, zero-correlation linear cryptanalysis and so forth. At INDOCRYPT 2014, Wang et al. gave zero-correlation attacks for 20-round SIMON32, 20-round SIMON48/72 and 21-round SIMON48/96. We investigate the security of whole family of SIMON by using zero-correlation linear cryptanalysis in this paper. For SIMON32 and SIMON48, we can attack one more round than the previous zero-correlation attacks given by Wang et al. We are the first one to give zero-correlation linear approximations of SIMON64, SIMON96 and SIMON128. These approximations are also utilized to attack the corresponding ciphers.","Title: Improved Differential Cryptanalysis of CAST-128 and CAST-256.\nYear: 2016\n\nAbstract: CAST-128 and CAST-256 are two symmetric algorithms designed by Adams in 1990s. Both of them adopt the CAST design procedure which makes them process a number of desirable cryptographic. CAST-128 is notably used as the default cipher in some versions of GNU Privacy Guard (GPG) and Pretty Good Privacy (PGP) systems. As an extension of CAST-128, CAST-256 was submitted as a candidate for the Advanced Encryption Standard (AES). Since they are widely used, there are many different attacks on them. Differential cryptanalysis is one of the most powerful tools. In this paper, we achieve improved differential cryptanalysis of both CAST-128 and CAST-256 based on the technique of accessing differential tables. Firstly, we propose a differential attack on 9-round CAST-128 with (2^{73}) encryptions and (2^{58}) chosen plaintexts. Although we cannot improve the number of attacked rounds, the time complexity is significantly reduced. Then we mount an improved differential attack on 10 quad-rounds of modified CAST-256 which increase one quad-round than previous attack. The time complexity of this attack is (2^{217}) encryptions, and the data complexity is (2^{123}) chosen plaintexts. As far as we know, these are the best known attacks on CAST-128 and CAST-256 under weak key assumption.","Title: Cryptanalysis of round-reduced ASCON.\nYear: 2017\n\nAbstract: ASCON是CAESAR竞赛的候选认证加密算法之一。在CT-RSA 2015上, 其设计者恢复了含有6轮初始化阶段的ASCON算法的密钥, 并给出了3/4轮的标签生成阶段的伪造攻击, 该伪造需求2^33/2^101个消息。这篇论文对包含7轮初始化阶段和5轮明文处理阶段的简化版ASCON算法执行密钥恢复攻击。除此之外, 我们对4/5/6轮的标签生成阶段建立了伪造, 所需数据量为2^9/2^17/2^33。该伪造相对之前具有实际攻击复杂度。","Title: New Linear Cryptanalysis of Chinese Commercial Block Cipher Standard SM4.\nYear: 2017\n\nAbstract: SM4 is a Chinese commercial block cipher standard used for wireless communication in China. In this paper, we use the partial linear approximation table of S-box to search for three rounds of iterative linear approximations of SM4, based on which the linear approximation for 20-round SM4 has been constructed. However, the best previous identified linear approximation only covers 19 rounds. At the same time, a linear approximation for 19-round SM4 is obtained, which is better than the known results. Furthermore, we show the key recovery attack on 24-round SM4 which is the best attack according to the number of rounds.","Title: Statistical integral attack on CAST-256 and IDEA.\nYear: 2018\n\nAbstract: Integral attack, as a powerful technique in the cryptanalysis field, has been widely utilized to evaluate the security of block ciphers. Integral distinguisher is based on balanced property on output with probability one. To obtain a distinguisher covering more rounds, an attacker will usually increase the data complexity by iterating through all values of more bits of plaintexts under the firm limitation that the data complexity should be less than the whole plaintext space. In order to release the limitation and reduce the data complexity, Wang et al. proposed a statistical integral distinguisher at FSE’16. In this paper, we exploit the statistical integral distinguisher to attack the IDEA and CAST-256 block ciphers. As a result, we manage to mount a key recovery attack on 29-round CAST-256 with 2 chosen plaintexts, 2 encryptions and 2 bytes of memory. By making a trade-off between the time complexity and data complexity, the attack can be achieved by 2 chosen plaintexts, 2 encryptions and 2 bytes of memory. As far as we know, these are the best attacks on CAST-256 in the single-key model without weak-key assumption so far. What’s more, we find an integral distinguisher of IDEA block cipher, which is the longest integral distinguisher known to now. By taking advantage of this distinguisher, we achieve a key recovery attack on 4.5-round IDEA with 2 known plaintexts, 2 encryptions and 2 bytes of memory respectively. It is the best integral attack with respect to the number of rounds.","Title: Statistical integral distinguisher with multi-structure and its application on AES-like ciphers.\nYear: 2018\n\nAbstract: Integral attack is one of the most powerful tools in the field of symmetric ciphers. In order to reduce the time complexity of original integral one, Wang et al. firstly proposed a statistical integral distinguisher at FSE’16. However, they don’t consider the cases that there are several integral properties on output and multiple structures of data should be used at the same time. In terms of such cases, we put forward a new statistical integral distinguisher, which enables us to reduce the data complexity comparing to the traditional integral ones under multiple structures. As illustrations, we use it into the known-key distinguishers on AES-like ciphers including AES and the permutations of Whirlpool, PHOTON and Grøstl-256 hash functions based on the Gilbert’s work at ASIACRYPT’14. These new distinguishers are the best ones comparing with previous ones under known-key setting. Moreover, we propose a secret-key distinguisher on 5-round AES under chosen-ciphertext mode. Its data, time and memory complexities are 2 chosen ciphertexts, 2 encryptions and 2 blocks. This is the best integral distinguisher on AES with secret S-box under secret-key setting so far.","Title: Zero-correlation attacks: statistical models independent of the number of approximations.\nYear: 2018\n\nAbstract: Multiple and multidimensional zero-correlation linear cryptanalysis have been two of the most powerful cryptanalytic techniques for block ciphers, and it has been shown that the differentiating factor of these two statistical models is whether distinct plaintexts are assumed or not. Nevertheless, questions remain regarding how these analyses can be universalized without any limitations and can be used to accurately estimate the data complexity and the success probability. More concretely, the current models for multiple zero-correlation (MPZC) and multidimensional zero-correlation (MDZC) cryptanalysis are not valid in the setting with a limited number of approximations and the accuracy of the estimation for data complexity can not be guaranteed. Besides, in a lot of cases, using too many approximations may cause an exhaustive search when we want to launch key-recovery attacks. In order to generalize the original models using the normal approximation of the -distribution, we provide a more accurate approach to estimate the data complexity and the success probability for MPZC and MDZC cryptanalysis without such approximation. Since these new models directly rely on the -distribution, we call them the MPZC and MDZC models. An interesting thing is that the chi-square-multiple zero-correlation (-MPZC) model still works even though we only have a single zero-correlation linear approximation. This fact puts an end to the situation that the basic zero-correlation linear cryptanalysis requires the full codebook under the known-plaintext attack setting. As an illustration, we apply the -MPZC model to analyze TEA and XTEA. These new attacks cover more rounds than the previous MPZC attacks. Moreover, we reconsider the multidimensional zero-correlation (MDZC) attack on 14-round CLEFIA-192 by utilizing less zero-correlation linear approximations. In addition, some other ciphers which already have MDZC analytical results are reevaluated and the data complexities under the new model are all less than or equal to those under the original model. Some experiments are conducted in order to verify the validity of the new models, and the experimental results convince us that the new models provide more precise estimates of the data complexity and the success probability.","Title: Cryptanalysis Of Aes-Prf And Its Dual\nYear: 2018\n\nAbstract: A dedicated pseudorandom function (PRF) called AES-PRF was proposed by Mennink and Neves at FSE 2018 (ToSC 2017, Issue 3). AES-PRF is obtained from AES by using the output of the 5-th round as the feed-forward to the output state. This paper presents extensive security analysis of AES-PRF and its variants. Specifically, we consider unbalanced variants where the output of the s-th round is used as the feed-forward. We also analyze the security of \"dual\" constructions of the unbalanced variants, where the input state is used as the feed-forward to the output of the s-th round. We apply an impossible differential attack, zero-correlation linear attack, traditional differential attack, zero correlation linear distinguishing attack and a meet-in-the-middle attack on these PRFs and reduced round versions. We show that AES-PRF is broken whenever a <= 2 or s >= 6, or reduced to 7 rounds, and Dual-AES-PRF is broken whenever s <= 4 or s >= 8. Our results on AES-PRF improve the initial security evaluation by the designers in various ways, and our results on Dual-AES-PRF give the first insight to its security.","Title: New Distinguisher On Reduced-Round Keccak Sponge Function\nYear: 2019\n\nAbstract: The security analysis of Keccak, the winner of SHA-3, has attracted considerable interest. Recently, some attention has been paid to distinguishing Keccak sponge function from random permutation. In EUROCRYPT'17, Huang et al. proposed conditional cube tester to recover the key of Keccak-MAC and Keyak and to construct practical distinguishing attacks on Keccak sponge function up to 7 rounds. In this paper, we improve the conditional cube tester model by refining the formulation of cube variables. By classifying cube variables into three different types and working the candidates of these types of cube variable carefully, we are able to establish a new theoretical distinguisher on 8-round Keccak sponge function. Our result is more efficient and greatly improves the existing results. Finally we remark that our distinguishing attack on the the reduced-round Keccak will not threat the security margin of the Keccak sponge function.","Title: More Accurate Differential Properties Of Led64 And Midori64\nYear: 2018\n\nAbstract: In differential cryptanalysis, a differential is more valuable than the single trail belonging to it in general. The traditional way to compute the probability of the differential is to sum the probabilities of all trails within it. The automatic tool for the search of differentials based on Mixed Integer Linear Programming (MILP) has been proposed and realises the task of finding multiple trails of a given differential. The problem is whether it is reliable to evaluate the probability of the differential traditionally. In this paper, we focus on two lightweight block ciphers - LED64 and Midori64 and show the more accurate estimation of differential probability considering the key schedule. Firstly, an automated tool based on Boolean Satisfiability Problem (SAT) is put forward to accomplish the automatic search of differentials for ciphers with S-boxes and is applied to LED64 and Midori64. Secondly, we provide an automatic approach to detect the right pairs following a given differential, which can be exploited to calculate the differential property. Applying this technique to the STEP function of LED64, we discover some differentials with enhanced probability. As a result, the previous attacks relying upon high probability differentials can be improved definitely. Thirdly, we present a method to compute an upper-bound of the weak-key ratio for a given differential, which is utilised to analyse 4-round differentials of Midori64. We detect two differentials whose weak-key ratios are much lower than the expected 50%. More than 78% of the keys will make these two differentials being impossible differentials. The idea of the estimation for an upper-bound of the weak-key ratio can be employed for other ciphers and allows us to launch differential attacks more reliably. Finally, we introduce how to compute the enhanced differential probability and evaluate the size of keys achieving the improved probability. Such a property may incur an efficient weak-key attack. For a 4-round differential of Midori64, we obtain an improved differential property for a portion of keys.","Title: Automatic Search for a Variant of Division Property Using Three Subsets.\nYear: 2019\n\nAbstract: The division property proposed at Eurocrypt’15 is a novel technique to find integral distinguishers, which has been applied to most kinds of symmetric ciphers such as block ciphers, stream ciphers, and authenticated encryption, etc. The original division property is word-oriented, and later the bit-based one was proposed at FSE’16 to get better integral property, which is composed of conventional bit-based division property (two-subset division property) and bit-based division property using three subsets (three-subset division property). Three-subset division property has more potential to achieve better integral distinguishers compared with the two-subset division property. The bit-based division property could not be to apply to ciphers with large block sizes due to its unpractical complexity. At Asiacrypt’16, the two-subset division property was modeled using Mixed Integral Linear Programming (MILP) technique, and the limits of block sizes were eliminated. However, there is still no efficient method searching for three-subset division property. The propagation rule of the XOR operation for (mathbb {L}) (The definition of (mathbb {L}) and (mathbb {K}) is introduced in Sect. 2.), which is a set used in the three-subset division property but not in two-subset one, requires to remove some specific vectors, and new vectors generated from (mathbb {L}) should be appended to (mathbb {K}) when Key-XOR operation is applied, both of which are difficult for common automatic tools such as MILP, SMT or CP. In this paper, we overcome one of the two challenges, concretely, we address the problem to add new vectors into (mathbb {K}) from (mathbb {L}) in an automatic search model. Moreover, we present a new model automatically searching for a variant three-subset division property (VTDP) with STP solver. The variant is weaker than the original three-subset division property (OTDP) but it is still powerful in some ciphers. Most importantly, this model has no constraints on the block size of target ciphers, which can also be applied to ARX and S-box based ciphers. As illustrations, some improved integral distinguishers have been achieved for SIMON32, SIMON32/48/64(102), SPECK32 and KATAN/KTANTAN32/48/64 according to the number of rounds or number of even/odd-parity bits.","Title: Linear cryptanalysis of reduced-round ICEBERG\nYear: 2012\n\nAbstract: ICEBERG is proposed by Standaert et al. in FSE 2004 for reconfigurable hardware implementations. ICEBERG is a fast involutional SPN block cipher and all its components are involutional and allow very efficient combinations of encryption/decryption. ICEBERG uses 64-bit block size and 128-bit key and the round number is 16. In this paper, we firstly find the best linear approximation of 6-round ICEBERG. We find that 2122 of ICEBERG keys are weak for linear cryptanalysis, and the linear deviation can be strengthened more heavily than the linear characteristic by the multi-path effect(Linear Hull). And we discover a 6-round linear hull consisting of 7 linear characteristics with a linear deviation of 2−29.99. Then we give a linear attack against 7-round ICEBERG for the weak keys.","Title: A SVD-based 2DOMP algorithm for compressed image sensing\nYear: 2018\n\nAbstract: We use the singular value decomposition of the separable measurement matrices to obtain the optimized separable reconstruction matrices and optimize the measurements. A two-dimensional orthogonal matching pursuit optimization algorithm based on singular value decomposition is proposed. Numerical experiments demonstrate that our proposed 2DOMP-SVD algorithm can significantly improve reconstruction quality and signal to noise ratio. Moreover, separable imaging operator arise naturally in many optical implementations and can satisfy the requirements for both the measurement matrix and the reconstruction matrix individually. And this design is suitable for general separable linear system.","Title: New integral attacks on SIMON.\nYear: 2017\n\nAbstract: SIMON is a family of lightweight block ciphers publicly released by National Security Agency (NSA). Up to now, there have been many cryptanalytic results on it by means of impossible differential, integral, zero-correlation linear cryptanalysis and so forth. In this study, the authors analyse the characteristic of the Boolean functions of SIMON32 and find that the presentation of zero-sum property...","Title: Conditional Cube Attack on Reduced-Round Keccak Sponge Function.\nYear: 2017\n\nAbstract: The security analysis of Keccak, the winner of SHA-3, has attracted considerable interest. Recently, some attention has been paid to the analysis of keyed modes of Keccak sponge function. As a notable example, the most efficient key recovery attacks on Keccak-MAC and Keyak were reported at EUROCRYPT'15 where cube attacks and cube-attack-like cryptanalysis have been applied. In this paper, we develop a new type of cube distinguisher, the conditional cube tester, for Keccak sponge function. By imposing some bit conditions for certain cube variables, we are able to construct cube testers with smaller dimensions. Our conditional cube testers are used to analyse Keccak in keyed modes. For reduced-round Keccak-MAC and Keyak, our attacks greatly improve the best known attacks in key recovery in terms of the number of rounds or the complexity. Moreover, our new model can also be applied to keyless setting to distinguish Keccak sponge function from random permutation. We provide a searching algorithm to produce the most efficient conditional cube tester by modeling it as an MILP (mixed integer linear programming) problem. As a result, we improve the previous distinguishing attacks on Keccak sponge function significantly. Most of our attacks have been implemented and verified by desktop computers. Finally we remark that our attacks on the reduced-round Keccak will not threat the security margin of Keccak sponge function.","Title: Related-Tweak Statistical Saturation Cryptanalysis And Its Application On Qarma\nYear: 2019\n\nAbstract: Statistical saturation attack takes advantage of a set of plaintext with some bits fixed while the others vary randomly, and then track the evolution of a non-uniform plaintext distribution through the cipher. Previous statistical saturation attacks are all implemented under single-key setting, and there is no public attack models under related-key/tweak setting. In this paper, we propose a new cryptanalytic method which can be seen as related-key/tweak statistical saturation attack by revealing the link between the related-key/tweak statistical saturation distinguishers and KDIB (Key Difference Invariant Bias) / TDIB (Tweak Difference Invariant Bias) ones. KDIB cryptanalysis was proposed by Bogdanov et al. at ASIACRYPT'13 and utilizes the property that there can exist linear trails such that their biases are deterministically invariant under key difference. And this method can be easily extended to TDIB distinguishers if the tweak is also alternated. The link between them provides a new and more efficient way to find related-key/tweak statistical saturation distinguishers in ciphers. Thereafter, an automatic searching algorithm for KDIB/TDIB distinguishers is also given in this paper, which can be implemented to find word-level KDIB distinguishers for S-box based key-alternating ciphers. We apply this algorithm to QARMA-64 and give related-tweak statistical saturation attack for 10-round QARMA-64 with outer whitening key. Besides, an 11-round attack on QARMA-128 is also given based on the TDIB technique. Compared with previous public attacks on QARMA including outer whitening key, all attacks presented in this paper are the best ones in terms of the number of rounds.","Title: Automatic search method for multiple differentials and its application on MANTIS\nYear: 2019\n\nAbstract: Multiple differential cryptanalysis is one of the extensions of classic differential cryptanalysis. In this paper, we present a generic automatic search method for clustering multiple differentials on a target block cipher. Our search method has two steps. Firstly, the sets of input and output differences will be determined. With these sets, we get different multiple differentials. Then for each one of these multiple differentials, we enumerate and record all satisfied differential trails, which leads to a more accurate evaluation of the multiple differentials distinguisher. Among these different multiple differentials distinguishers, we can choose the best one for key recovery attack. We demonstrate our search method by applying it on the part of differentials of the block cipher MANTIS. As a result, we find a new 10-round multiple differentials distinguisher with probability 2−55.98 and an 11-round multiple differentials distinguisher with probability 2−63.71, which is the longest distinguisher for MANTIS so far as we know. This new 10-round distinguisher can lead to a better signal-to-noise ratio, so we derive an improved key recovery attack on MANTIS-6 with the complexity of about 251.79 chosen-plaintext queries, 251.91 encryptions and data-time product 2103.70, which is better than the previous best one with data-time product 2110.61. Aiming at exploring the gap between the performance of multiple differential attack and the security margin on MANTIS, we also use the 11-round distinguisher to derive a key recovery attack on MANTIS-7 with the complexity of about 261.86 chosen-plaintext queries, 2102.92 encryptions and data-time product 2164.78. It does not threat the security of full version MANTIS (MANTIS-7) since the security bound of data-time product claimed by the designers is 2126.","Title: Linear Cryptanalyses Of Three Aeads With Gift-128 As Underlying Primitives\nYear: 2021\n\nAbstract: This paper considers the linear cryptanalyses of Authenticated Encryptions with Associated Data (AEADs) GIFT-COFB, SUNDAE-GIFT, and HyENA. All of these proposals take GIFT-128 as underlying primitives. The automatic search with the Boolean satisfiability problem (SAT) method is implemented to search for linear approximations that match the attack settings concerning these primitives. With the newly identified approximations, we launch key-recovery attacks on GIFT-COFB, SUNDAE-GIFT, and HyENA when the underlying primitives are replaced with 16-round, 17-round, and 16-round versions of GIFT-128. The resistance of GIFT-128 against linear cryptanalysis is also evaluated. We present a 24-round key-recovery attack on GIFT-128 with a newly obtained 19-round linear approximation. We note that the attack results in this paper are far from threatening the security of GIFT-COFB, SUNDAE-GIFT, HyENA, and GIFT-128.","Title: Forced Independent Optimized Implementation of 4-Bit S-Box\nYear: 2021\n\nAbstract: Searching the optimal circuit implementation of a Boolean function is still an open problem. This work proposes a new optimizing scheme, which could find circuit expressions with optimal gate equivalent complexity (GEC) using SAT solvers under a depth-L framework. To obtain a better GEC performance in the optimizing scheme, we first propose the ternary and area profile models for SAT problems. The former introduces multiple efficient 3-input logic gates, and the latter takes the different weights of various gates into account in solving. To demonstrate the validity and usefulness, we use our optimizing methodology to search optimized implementation of a given 4-bit S-box with the forced independent property. For an S-box hardware implementation, its forced independent property can ensure that no gate is shared between every two component-circuits, which is beneficial to prevent Differential Fault Analysis (DFA). Finally, we evaluate the implementation performances of two models (i.e., ternary and binary models) and two implementation approaches (i.e., Table-based and Boolean expression methods) by case studies covering several know S-boxes. The experimental results show that our models and approach have better area performance for the S-boxes with forced independence property in most instances.","Title: Related-Tweakey Impossible Differential Attack On Qarma-128\nYear: 2022\n\nAbstract: Dear editor,\r\nQARMA[1]is a family of hardware-oriented lightweight tweakable block ciphers designed by Avanzi.It contains two versions,which support block sizes of 64 and 128 bits,de-noted by QARMA-64 and QARMA-128,respectively.The structure of QARMA is an Even-Mansour scheme[2]with a keyed pseudo-reflector,and the TWEAKEY framework is taken as an inspiration.","Title: A Column Generation Tailored To Electric Vehicle Routing Problem With Nonlinear Battery Depreciation\nYear: 2022\n\nAbstract: Since the battery remains a significant cost component of electric vehicles (EVs), controlling the depreciation costs of EVs' batteries is of great importance, especially from the perspective of the electric vehicle routing problem (EVRP). However, most existing studies on the EVRP have not explicitly considered the battery depreciation in the cost function; instead, it has been treated as a linear function of an EV's travel distance or time. In fact, the depth-of-discharge (DOD) significantly affects the battery life and leads to a naturally nonlinear depreciation function, which can be used to calculate the battery life more accurately. In this paper, we adopt three battery depreciation methods to investigate and compare their influences on the EVRP with time windows (EVRPTW): (1) a nonlinear function of DOD; (2) a linear function of charge-discharge cycles; and (3) a linear function of total traveling distance. The first method is mainly studied, and the remaining two methods are verified as comparative analyses. Meanwhile, both full and partial charge policies are considered to formulate the problem. By combining the charging policies and battery depreciation methods, four mixed -integer programming models are formulated, aiming to minimize the total cost. To pursue exact solutions in acceptable computing time, a column generation algorithm (CG) that relies on four tailored labeling algorithms (LAs) is designed. The LAs are used to accelerate the calculation speed of the pricing problem. The most considerable difficulty of solving pricing problems lies in the complex endogenous relationships among recharging time, drivers' waiting time, battery state-of-charge (SOC), battery depreciation, battery rated capacity, and driving distance. The LAs need to find a tradeoff among them and generate the shortest paths. Given this, we design specific and elaborate resource extension functions (REFs) for the four models, respectively, which is an extension to Desaulniers et al. (2016). Although the REFs are intricate, they work well with the help of dominance rules. Benchmark instances are performed to verify the efficiencies of the CG and LAs, which shows that instances with 25-nodes are solvable. In computational studies, we find that models considering the DOD can increase the battery life and decrease the total cost by 9%-10%. Moreover, several insights for better management of EV fleets are obtained.","Title: SAND: an AND-RX Feistel lightweight block cipher supporting S-box-based security evaluations\nYear: 2022\n\nAbstract: We revisit designing AND-RX block ciphers, that is, the designs assembled with the most fundamental binary operations-AND, Rotation and XOR operations and do not rely on existing units. Likely, the most popular representative is the NSA cipher SIMON, which remains one of the most efficient designs, but suffers from difficulty in security evaluation. As our main contribution, we propose SAND, a new family of lightweight AND-RX block ciphers. To overcome the difficulty regarding security evaluation, SAND follows a novel design approach, the core idea of which is to restrain the AND-RX operations to be within nibbles. By this, SAND admits an equivalent representation based on a 4x8synthetic S-box (SSb). This enables the use of classical S-box-based security evaluation approaches. Consequently, for all versions of SAND, (a) we evaluated security bounds with respect to differential and linear attacks, and in both single-key and related-key scenarios; (b) we also evaluated security against impossible differential and zero-correlation linear attacks. This better understanding of the security enables the use of a relatively simple key schedule, which makes the ASIC round-based hardware implementation of SAND to be one of the state-of-art Feistel lightweight ciphers. As to software performance, due to the natural bitslice structure, SAND reaches the same level of performance as SIMON and is among the most software-efficient block ciphers.","Title: Related-Tweakey Impossible Differential Attack on Reduced-Round SKINNY-AEAD M1/M3\nYear: 2022\n\nAbstract: SKINNY-AEAD is one of the second-round candidates of the Lightweight Cryptography Standardization project held by NIST. SKINNY-AEAD M1 is the primary member of six SKINNY-AEAD schemes, while SKINNY-AEAD M3 is another member with a small tag. In the design document, only security analyses of their underlying primitive SKINNY-128-384 are provided. Besides, there are no valid third-party analyses on SKINNY-AEAD M1/M3 according to our knowledge. Therefore, this paper focuses on constructing the first third-party security analyses on them under a nonce-respecting scenario. By taking the encryption mode of SKINNY-AEAD into consideration and exploiting several properties of SKINNY, we can deduce some necessary constraints on the input and tweakey differences of related-tweakey impossible differential distinguishers. Under these constraints, we can find distinguishers suitable for mounting powerful tweakey recovery attacks. With the help of the automatic searching algorithms based on STP, we find some 14-round distinguishers. Based on one of these distinguishers, we mount a 20-round and an 18-round tweakey recovery attack on SKINNY-AEAD M1/M3. To the best of our knowledge, all these attacks are the best ones so far.","Title: Integral Attacks on Pyjamask-96 and Round-Reduced Pyjamask-128\nYear: 2022\n\nAbstract: In order to provide benefits in the areas of fully homomorphic encryption (FHE), multi-party computation (MPC), post-quantum signature schemes, or efficient masked implementations for side-channel resistance, reducing the number of multiplications has become a quite popular trend for the symmetric cryptographic primitive designs. With an aggressive design strategy exploiting the extremely simple and low-degree S-box and low number of rounds, Pyjamask, the fundamental block cipher of the AEAD with the same name, has the smallest number of AND gates per bit among all the existing block ciphers (except Low-MC or Rasta which work on unconventional plaintext/key sizes). Thus, although the AEAD Pyjamask stuck at the second round of the NIST lightweight cryptography standardization process, the block cipher Pyjamask itself still attracts a lot of attention. Not very unexpectedly, the low degree and the low number of rounds are the biggest weakness of Pyjamask. At FSE 2020, Dobraunig et al. successfully mounted an algebraic and higher-order differential attack on full Pyjamask-96, one member of the Pyjamask block cipher family. However, the drawback of this attack is that it has to use the full codebook, which makes the attack less appealing. In this paper, we take integral attacks as our weapon, which are also sensitive to the low degree. Based on a new 11-round integral distinguishes found by state-of-the-art detection techniques, and combined with the relationship between round keys that reduces the involved keys, we give the key recovery attack on the full Pyjamask-96 without the full codebook for the first time. Further, the algebraic and higher-order differential technique does not work for Pyjamask-128, the other member of the Pyjamask block cipher family. To better understand the security margin of Pyjamask-128, we present the first third-party cryptanalysis on Pyjamask-128 up to 11 out of 14 rounds.","Title: An STP-based model toward designing S-boxes with good cryptographic properties\nYear: 2022\n\nAbstract: The substitution box (S-box) is an important nonlinear component in most symmetric cryptosystems and thus should have good properties. Its difference distribution table (DDT) and linear approximation table (LAT) affect the security of the cipher against differential and linear cryptanalysis. In most previous work, differential uniformity and linearity of an S-box are two primary cryptographic properties to impact the resistance against differential and linear attacks. In some cases, the branch number and fixed point are also be considered. However, other important cryptographic properties such as the frequency of differential uniformity (resp. linearity) and the number of Bad Input and Bad Output (BIBO) patterns in DDT (resp. LAT) are often ignored. These properties substantially affect lightweight cryptography based on substitution bit permutation networks (SbPN) such as PRESENT, GIFT and RECTANGLE. This paper introduces a new method to search for S-boxes satisfying all above criteria simultaneously. In our strategy, we transform the process of searching for S-boxes under certain constraints on cryptographic properties into a satisfiability (SAT) problem. As applications, we use our new approach to search out 4-bit and 5-bit S-boxes with the same or better cryptographic properties compared with the S-boxes from well-known ciphers. Finally, we also utilize our method to verify a conjecture proposed by Boura et al. in the case of all 3-bit and 4-bit S-boxes. We propose a proposition and two corollaries to reduce the search space in this verification.","Title: Cryptanalysis of the AEAD and hash algorithm DryGASCON\nYear: 2022\n\nAbstract: The DryGASCON scheme was one of authenticated encryption (AE) algorithms submitted to the ongoing NIST Lightweight Cryptography Standardization Process. Such a competition aims to standardize lightweight cryptographic algorithms and determine lightweight AE schemes that are suitable for use in constrained environments suitable for several emerging areas in which highly-constrained devices are interconnected. This article deals with DryGASCON and aims to evaluate its security. The reasons for this choice are twofold. The first reason is related to its unique design. The second one is that no forgery cryptanalysis has been performed on it in the literature to the best of our knowledge. Specifically, this paper presents practical forgery attacks on DryGASCON by exploiting internal collisions of the underlying permutation. During our cryptanalysis, we investigate collisions and discuss how to find them. Next, we mounted forgery attacks on DryGASCON128 with an optimal probability 2− 13 for a class of weak keys and with certainty (optimal probability 1) for pairs of related keys. We show that the number of elements from the weak-key class depends on the size of the secret keys. In addition, we also find forgeries of DryGASCON256 in the related-key scenario. Forgery attacks succeeded without the reuse of nonce. Our results threaten the authenticity and robustness of DryGASCON. However, thanks to our analysis, we shed light on the causes of its weaknesses, and we manage to draw constructive conclusions and recommendations for future AE designs schemes, notably similar to DryGASCON.","Title: Towards Low-Latency Implementation of Linear Layers\nYear: 2022\n\nAbstract: Lightweight cryptography features a small footprint and/or low computational complexity. Low-cost implementations of linear layers usually play an important role in lightweight cryptography. Although it has been shown by Boyar et al. that finding the optimal implementation of a linear layer is a Shortest Linear Program (SLP) problem and NP-hard, there exist a variety of heuristic methods to search for near-optimal solutions. This paper considers the low-latency criteria and focuses on the heuristic search of lightweight implementation for linear layers. Most of the prior approach iteratively combines the inputs (of linear layers) to reach the output, which can be regarded as the forward search. To better adapt the low-latency criteria, we propose a new framework of backward search that attempts to iteratively split every output (into an XORing of two bits) until all inputs appear. By bounding the time of splitting, the new framework can find a sub-optimal solution with a minimized depth of circuits. We apply our new search algorithm to linear layers of block ciphers and find many low-latency candidates for implementations. Notably, for AES Mixcolumns, we provide an implementation with 103 XOR gates with a depth of 3, which is among the best hardware implementations of the AES linear layer. Besides, we obtain better implementations in XOR gates for 54.3% of 4256 Maximum Distance Separable (MDS) matrices proposed by Li et al. at FSE 2019. We also achieve an involutory MDS matrix (in M-4(GL(8, F-2))) whose implementation uses the lowest number (i.e., 86, saving 2 from the state-of-the-art result) of XORs with the minimum depth.","Title: Addendum to Linear Cryptanalyses of Three AEADs with GIFT-128 as Underlying Primitives\nYear: 2022\n\nAbstract: In ToSC 2021(2), Sun et al. implemented an automatic search with the Boolean satisfiability problem (SAT) method on GIFT-128 and identified a 19-round linear approximation with the expected linear potential being 2(-117.43), which is utilised to launch a 24-round attack on the cipher. In this addendum, we discover a new 19-round linear approximation with a lower expected linear potential. However, in the attack, one more round can be appended after the distinguisher. As a result, we improve the previous optimal linear attack by one round and put forward a 25-round linear attack. Given that the optimal differential attack on GIFT-128, for now, covers 27-round, the resistances of the cipher against differential and linear attacks still have a 2-round gap.","Title: Related-Tweak Impossible Differential Cryptanalysis of Reduced-Round TweAES\nYear: 2021\n\nAbstract: We consider the related-tweak impossible differential cryptanalysis of TweAES. It is one of the underlying primitives of Authenticated Encryption with Associated Data (AEAD) scheme ESTATE which was accepted as one of second-round candidates in the NIST Lightweight Cryptography Standardization project. Firstly, we reveal several properties of TweAES, which show what kinds of distinguishers are more effective in recovering keys. With the help of automatic solver Simple Theorem Prover (STP), we achieve many 5.5-round related-tweak impossible differentials with fixed input differences and output differences that just have one active byte. Then, we implement 8-round key recovery attacks against TweAES based on one of these 5.5-round distinguishers. Moreover, another 5.5-round distinguisher that has four active bytes at the end is utilized to mount a 7-round key recovery attack against TweAES, which needs much lower attack complexities than the 6-round related-tweak impossible differential attack of TweAES in the design document. Our 8round key recovery attack is the best one against TweAES in terms of the number of rounds and complexities so far.","Title: Improved Attacks on GIFT-64\nYear: 2021\n\nAbstract: One of the well-known superiorities of GIFT-64 over PRESENT lies in the correction of the strong linear hull effect. However, apart from the investigation of the 9-round linear hull effect in the design document, we find no linear attack result on GIFT-64. Although we do not doubt the security of GIFT-64 regarding the linear cryptanalysis, the actual resistance of the cipher to the linear attack should be evaluated since it promotes a comprehensive perception of the soundness of GIFT-64. Motivated by this observation, we implement an automatic search and find a 12-round linear distinguisher whose dominating trail is an optimal linear characteristic. Following that, the first 19-round linear attack is launched by utilising the newly identified distinguisher. On the other side, we notice that the previous differential attack of GIFT-64 covering 20 rounds claims the entire codebook. To reduce the data complexity of the 20-round attack, we apply the automatic method to exhaustively check 13-round differential trails with probabilities no less than \n \n \n \n $$2^{-64}$$\n \n and identify multiple 13-round differentials facilitating 20-round attacks without using the full codebook. One of the candidate differentials with the maximum probability and the minimum number of guessed subkey bits is then employed to realise the first 20-round differential attack without relying on the complete codebook. Given the newly obtained results, we conjecture that the resistances of GIFT-64 against differential and linear attacks do not have a significant gap. Also, we note that the attack results in this paper are far from threatening the security of GIFT-64.","Title: Revisiting the Extension of Matsui's Algorithm 1 to Linear Hulls: Application to TinyJAMBU\nYear: 2022\n\nAbstract: At EUROCRYPT '93, Matsui introduced linear cryptanalysis. Both Matsui's Algorithm 1 and 2 use a linear approximation involving certain state bits. Algorithm 2 requires partial encryptions or decryptions to obtain these state bits after guessing extra key bits. For ciphers where only part of the state can be obtained, like some stream ciphers and authenticated encryption schemes, Algorithm 2 will not work efficiently since it is hard to implement partial encryptions or decryptions. In this case, Algorithm 1 is a good choice since it only involves these state bits, and one bit of key information can be recovered using a single linear approximation trail. However, when there are several strong trails containing the same state bits, known as the linear hull effect, recovering key bits with Algorithm 1 is infeasible. To overcome this, Rock and Nyberg extended Matsui's Algorithm 1 to linear hulls. However, Rock and Nyberg found that their theoretical estimates are quite pessimistic for low success probabilities and too optimistic for high success probabilities. To deal with this, we construct new statistical models where the theoretical success probabilities are in a good accordance with experimental ones, so that we provide the first accurate analysis of the extension of Matsui's Algorithm 1 to linear hulls. To illustrate the usefulness of our new models, we apply them to one of the ten finalists of the NIST the first cryptanalysis under the nonce-respecting setting on the full TinyJAMBU v1 and the round-reduced TinyJAMBU v2, where partial key bits are recovered. Our results do not violate the security claims made by the designers.","Title: More Inputs Makes Difference: Implementations of Linear Layers Using Gates with More Than Two Inputs\nYear: 2022\n\nAbstract: Lightweight cryptography ensures cryptography applications to devices with limited resources. Low-area implementations of linear layers usually play an essential role in lightweight cryptography. The previous works have provided plenty of methods to generate low-area implementations using 2-input xor gates for various linear layers. However, it is still challenging to search for smaller implementations using two or more inputs xor gates. This paper, inspired by Banik et al., proposes a novel approach to construct a quantity of lower area implementations with (n + 1)-input gates based on the given implementations with n-input gates. Based on the novel algorithm, we present the corresponding search algorithms for n = 2 and n = 3, which means that we can efficiently convert an implementation with 2-input xor gates and 3-input xor gates to lower-area implementations with 3-input xor gates and 4-input xor gates, respectively. We improve the previous implementations of linear layers for many block ciphers according to the area with these search algorithms. For example, we achieve a better implementation with 4-input xor gates for AES MixColumns, which only requires 243 GE in the STM 130 nm library, while the previous public result is 258.9 GE. Besides, we obtain better implementations for all 5500 lightweight matrices proposed by Li et al. at FSE 2019, and the area for them is decreased by about 21% on average.","Title: A Greater GIFT: Strengthening GIFT Against Statistical Cryptanalysis\nYear: 2022\n\nAbstract: GIFT-64 is a 64-bit block cipher with a 128-bit key that is more lightweight than PRESENT. This paper provides a detailed analysis of GIFT-64 against differential and linear attacks. Our work complements automatic search methods for the best differential and linear characteristics with a careful manual analysis. This hybrid approach leads to new insights. In the differential setting, we theoretically explain the existence of differential characteristics with two active S-boxes per round and derive some novel properties of these characteristics. Furthermore, we prove that all optimal differential characteristics of GIFT-64 covering more than seven rounds must activate two S-boxes per round. We can construct all optimal characteristics by hand. In parallel to the work in the differential setting, we conduct a similar analysis in the linear setting. However, unlike the clear view in differential setting, the optimal linear characteristics of GIFT-64 must have at least one round activating only one S-box. Moreover, with the assistance of automatic searching methods, we identify 24 GIFT-64 variants achieving better resistance against differential attack while maintaining a similar security level against a linear attack. Since the new variants strengthen GIFT-64 against statistical cryptanalysis, we claim that the number of rounds could be reduced from 28 to 26 for the variants. This observation enables us to create a cipher with lower energy consumption than GIFT-64. Similarly to the case in GIFT-64, we do not claim any related-key security for the round-reduced variant as this is not relevant for most applications."],"string":"[\n \"Title: Integral and multidimensional linear distinguishers with correlation zero\\nYear: 2012\\n\\nAbstract: Zero-correlation cryptanalysis uses linear approximations holding with probability exactly 1/2. In this paper, we reveal fundamental links of zero-correlation distinguishers to integral distinguishers and multidimensional linear distinguishers. We show that an integral implies zero-correlation linear approximations and that a zero-correlation linear distinguisher is actually a special case of multidimensional linear distinguishers. These observations provide new insight into zero-correlation cryptanalysis which is illustrated by attacking a Skipjack variant and round-reduced CAST-256 without weak key assumptions.\",\n \"Title: Difierential Cryptanalysis of PRESENT\\nYear: 2007\\n\\nAbstract: PRESENT is proposed by A.Bogdanov et al. in CHES 2007 for extremely constrained environments such as RFID tags and sensor networks. In this paper, we flnd out the difierential characteristics for r-round(5 • r • 15), then give the difierential cryptanalysis on reduced-round variants of PRESENT. We attack 16-round PRESENT using 264 chosen plaintexts, 232 6-bit counters, and 265 memory accesses.\",\n \"Title: Zero-Correlation Linear Cryptanalysis with FFT and Improved Attacks on ISO Standards Camellia and CLEFIA.\\nYear: 2013\\n\\nAbstract: Zero-correlation linear cryptanalysis is based on the linear approximations with correlation exactly zero, which essentially generalizes the integral property, and has already been applied to several block ciphers - among others, yielding best known attacks to date on round-reduced TEA and CAST-256 as published in FSE'12 and ASI-ACRYPT'12, respectively. In this paper, we use the FFT (Fast Fourier Transform) technique to speed up the zero-correlation cryptanalysis. First, this allows us to improve upon the state-of-the-art cryptanalysis for the ISO/IEC standard and CRYPTREC-portfolio cipher Camellia. Namely, we present zero-correlation attacks on 11-round Camellia-128 and 12-round Camellia192 with FL/FL-1 and whitening key starting from the first round, which is an improvement in the number of attacked rounds in both cases. Moreover, we provide multidimensional zero-correlation cryptanalysis of 14-round CLEFIA-192 and 15-round CLEFIA-256 that are attacks on the highest numbers of rounds in the classical single-key setting, respectively, with improvements in memory complexity.\",\n \"Title: Related-Key Impossible Differential Attack on Reduced-Round LBlock.\\nYear: 2014\\n\\nAbstract: LBlock is a 32-round lightweight block cipher with 64-bit block size and 80-bit key. This paper identifies 16-round related-key impossible differentials of LBlock, which are better than the 15-round related-key impossible differentials used in the previous attack. Based on these 16-round related-key impossible differentials, we can attack 23 rounds of LBlock while the previous related-key impossible differential attacks could only work on 22-round LBlock. This makes our attack on LBlock the best attack in terms of the number of attacked rounds. ? 2014 Springer Science+Business Media New York & Science Press, China.\",\n \"Title: Side Channel Cube Attack on PRESENT\\nYear: 2009\\n\\nAbstract: As an ultra-lightweight block cipher, PRESENT is presented by A. Bogdanov et al. in CHES 2007. In this paper, we detect the non-random properties in the first four rounds of PRESENT based on cube attack proposed by Shamir et al. By analyzing the features of the S-box and pLayer, we give the side channel cube attack on PRESENT. If any output bit of the third round is leaked, we can recover the total 80-bit key. Especially, for the leaked bit 1, bit 2 or bit 3 of the output bits in the third round, we can also recover 80-bit key with lower computing complexity compared to other leaked bits, and our attack requires 215 chosen plaintexts and 232 31-round PRESENT encryptions.\",\n \"Title: Differential-algebraic cryptanalysis of reduced-round of Serpent-256.\\nYear: 2010\\n\\nAbstract: Differential cryptanalysis is a general cryptanalytic tool that makes use of differentials over some rounds of a cipher, combined\\n with some key bit guesses of one or two rounds. This paper introduces a new cryptanalysis strategy of block ciphers named\\n differential-algebraic cryptanalysis. The idea of differential-algebraic cryptanalysis is to find a differential with high\\n probability and build the multivariable system equations for the last few rounds. The subkey values of the last few rounds\\n can be obtained by filtering the solutions of system equations instead of guessing all possible subkey values. We use the\\n differential-algebraic cryptanalysis to break 8-round Serpent-256. Our attack can recover the 256-bit key with 283 chosen plaintexts, 2180.4 8-round Serpent-256 encryptions and 2176.7 bytes memory. Compared with the previous differential cryptanalysis results, both the data complexity and the time complexity\\n are reduced, but the memory requirements are increased. The time complexity and the memory requirements are very close, and\\n a time-memory tradeoff is exploited.\",\n \"Title: Practical attack on the full MMB block cipher\\nYear: 2011\\n\\nAbstract: Modular Multiplication based Block Cipher (MMB) is a block cipher designed by Daemen et al. as an alternative to the IDEA block cipher. In this paper, we give a practical sandwich attack on MMB with adaptively chosen plaintexts and ciphertexts. By constructing a 5-round sandwich distinguisher of the full 6-round MMB with probability 1, we recover the main key of MMB with text complexity 240 and time complexity 240 MMB encryptions. We also present a chosen plaintexts attack on the full MMB by employing the rectangle-like sandwich attack, which the complexity is 266.5 texts, 266.5 MMB encryptions and 270.5 bytes of memory. In addition, we introduce an improved differential attack on MMB with 296 chosen plaintexts, 296 encryptions and 266 bytes of memory. Especially, even if MMB is extended to 7 rounds, the improved differential attack is applicable with the same complexity as that of the full MMB.\",\n \"Title: Impossible differential cryptanalysis of the lightweight block ciphers TEA, XTEA and HIGHT\\nYear: 2012\\n\\nAbstract: TEA, XTEA and HIGHT are lightweight block ciphers with 64-bit block sizes and 128-bit keys. The round functions of the three ciphers are based on the simple operations XOR, modular addition and shift/rotation. TEA and XTEA are Feistel ciphers with 64 rounds designed by Needham and Wheeler, where XTEA is a successor of TEA, which was proposed by the same authors as an enhanced version of TEA. HIGHT, which is designed by Hong et al., is a generalized Feistel cipher with 32 rounds. These block ciphers are simple and easy to implement but their diffusion is slow, which allows us to find some impossible properties. This paper proposes a method to identify the impossible differentials for TEA and XTEA by using the weak diffusion, where the impossible differential comes from a bit contradiction. Our method finds a 14-round impossible differential of XTEA and a 13-round impossible differential of TEA, which result in impossible differential attacks on 23-round XTEA and 17-round TEA, respectively. These attacks significantly improve the previous impossible differential attacks on 14-round XTEA and 11-round TEA given by Moon et al. from FSE 2002. For HIGHT, we improve the 26-round impossible differential attack proposed by Özen et al.; an impossible differential attack on 27-round HIGHT that is slightly faster than the exhaustive search is also given.\",\n \"Title: New Distinguishing Attack on MAC Using Secret-Prefix Method\\nYear: 2009\\n\\nAbstract: This paper presents a new distinguisher which can be applied to secret-prefix MACs with the message length prepended to the message before hashing. The new distinguisher makes use of a special truncated differential path with high probability to distinguish an inner near-collision in the first round. Once the inner near-collision is detected, we can recognize an instantiated MAC from a MAC with a random function. The complexity for distinguishing the MAC with 43-step reduced SHA-1 is 2124.5 queries. For the MAC with 61-step SHA-1, the complexity is 2154.5 queries. The success probability is 0.70 for both.\",\n \"Title: Key Difference Invariant Bias in Block Ciphers\\nYear: 2013\\n\\nAbstract: In this paper, we reveal a fundamental property of block ciphers: There can exist linear approximations such that their biases ε are deterministically invariant under key difference. This behaviour is highly unlikely to occur in idealized ciphers but persists, for instance, in 5-round AES. Interestingly, the property of key difference invariant bias is independent of the bias value ε itself and only depends on the form of linear characteristics comprising the linear approximation in question as well as on the key schedule of the cipher. We propose a statistical distinguisher for this property and turn it into an key recovery. As an illustration, we apply our novel cryptanalytic technique to mount related-key attacks on two recent block ciphers -- LBlock and TWINE. In these cases, we break 2 and 3 more rounds, respectively, than the best previous attacks.\",\n \"Title: Differential cryptanalysis of reduced-round ICEBERG\\nYear: 2012\\n\\nAbstract: ICEBERG is proposed by Standaert et al. in FSE 2004 for reconfigurable hardware implementations. It uses 64-bit block size and 128-bit key and the round number is 16. Specially, it is a SPN block cipher and all components are involutional and allow very efficient combinations of encryption/decryption. In this paper, we propose an elaborate method to identify the 6-round differentials and present the differential attack on 7-round ICEBERG with 257 chosen plaintexts and 290.28 7-round encryptions. Then we use multiple differentials to attack 8-round ICEBERG with 263 chosen plaintexts and 296 8-round encryptions. The previous linear cryptanalysis can only attack 7-round ICEBERG with the whole codebook. It means that ICEBERG is more resistant to linear cryptanalysis than differential cryptanalysis. Although our attack cannot threat ICEBERG, we give the best attack for ICEBERG published to date and our elaborate method to identify multiple differential can be used for other similar block ciphers.\",\n \"Title: Differential cryptanalysis of reduced-round PRESENT\\nYear: 2008\\n\\nAbstract: PRESENT is proposed by A. Bogdanov et al. in CHES 2007 for extremely constrained environments such as RFID tags and sensor networks. In this paper, we present the differential characteristics for r-round(5 ≤ r ≤ 15), then give the differential cryptanalysis on reduced-round variants of PRESENT. We attack 16-round PRESENT using 264 chosen plaintexts, 232 6-bit counters, and 264 memory accesses.\",\n \"Title: How to search linear approximation for large non-surjective S-box\\nYear: 2011\\n\\nAbstract: Linear cryptanalysis is a general form of cryptanalysis based on identifying the linear approximations of a cipher. It is one of the two most widely used attacks on block ciphers. In order to resist the differential cryptanalysis, the S-box with large output bit number is applied in block cipher, for example CAST-128 and CAST-256 use the 8 × 32 S-boxes. In addition, the S-boxes are often constructed based on bent functions to resist the linear cryptanalysis and the S-boxes are non-surjective mapping. Therefore, for the large non-surjective S-box, to identify the best linear approximation with zero input mask and nonzero output mask is difficult due to the unaccepted computation time. In this paper, we will give an efficient computing method to find such best linear approximations for the non-surjective large S-boxes using parallel computation in practical time. This computing method can help to estimate the resistant property for some kind of linear cryptanalysis of block ciphers with this kind of S-box.\",\n \"Title: Zero correlation linear cryptanalysis with reduced data complexity\\nYear: 2012\\n\\nAbstract: Zero correlation linear cryptanalysis is a novel key recovery technique for block ciphers proposed in [5]. It is based on linear approximations with probability of exactly 1/2 (which corresponds to the zero correlation). Some block ciphers turn out to have multiple linear approximations with correlation zero for each key over a considerable number of rounds. Zero correlation linear cryptanalysis is the counterpart of impossible differential cryptanalysis in the domain of linear cryptanalysis, though having many technical distinctions and sometimes resulting in stronger attacks. In this paper, we propose a statistical technique to significantly reduce the data complexity using the high number of zero correlation linear approximations available. We also identify zero correlation linear approximations for 14 and 15 rounds of TEA and XTEA. Those result in key-recovery attacks for 21-round TEA and 25-round XTEA, while requiring less data than the full code book. In the single secret key setting, these are structural attacks breaking the highest number of rounds for both ciphers. The findings of this paper demonstrate that the prohibitive data complexity requirements are not inherent in the zero correlation linear cryptanalysis and can be overcome. Moreover, our results suggest that zero correlation linear cryptanalysis can actually break more rounds than the best known impossible differential cryptanalysis does for relevant block ciphers. This might make a security re-evaluation of some ciphers necessary in the view of the new attack.\",\n \"Title: A hybrid approach for authenticating MPEG-2 streaming data\\nYear: 2007\\n\\nAbstract: There are two main approaches for authenticating digital streams, namely the tree chaining [1] and the hash chaining [2,3]. Both approaches have their disadvantages. Hash chaining is superior for low communication overhead, however, it is not resilient to packet loss and it has a longer verification delay. On the other hand, tree chaining is more robust even if packet loss occurs and with shorter verification delay, but the communication overhead is too high to be tolerable, especially in online applications. In this paper, we try to combine the two techniques and propose a hybrid scheme for authenticating MPEG-2 streaming data, which are still used by real application systems, by taking advantage of the characteristics of MPEG frames. The hybrid approach is shown to be more effective as compared to the other two approaches.\",\n \"Title: Multidimensional zero-correlation attacks on lightweight block cipher HIGHT: Improved cryptanalysis of an ISO standard\\nYear: 2014\\n\\nAbstract: HIGHT is a block cipher designed in Korea with the involvement of Korea Information Security Agency. It was proposed at CHES 2006 for usage in lightweight applications such as sensor networks and RFID tags. Lately, it has been adopted as ISO standard. Though there is a great deal of cryptanalytic results on HIGHT, its security evaluation against the recent zero-correlation linear attacks is still lacking. At the same time, the Feistel-type structure of HIGHT suggests that it might be susceptible to this type of cryptanalysis. In this paper, we aim to bridge this gap. We identify zero-correlation linear approximations over 16 rounds of HIGHT. Based upon those, we attack 27-round HIGHT (round 4 to round 30) with improved time complexity and practical memory requirements. This attack of ours is the best result on HIGHT to date in the classical single-key setting. We also provide the first attack on 26-round HIGHT (round 4 to round 29) with the full whitening key.\",\n \"Title: On the (In)Equivalence of Impossible Differential and Zero-Correlation Distinguishers for Feistel- and Skipjack-Type Ciphers.\\nYear: 2014\\n\\nAbstract: For many word-oriented block ciphers, impossible differential (ID) and zero-correlation linear (ZC) cryptanalyses are among the most powerful attacks. Whereas ID cryptanalysis makes use of differentials which never occur, the ZC cryptanalysis relies on linear approximations with correlations equal to zero. While the key recovery parts of ID and ZC attacks may differ and are often specific to the target cipher, the underlying distinguishing properties frequently cover the same number of rounds. However, in some cases, the discrepancy between the best known IDs and ZC approximations is rather significant. At EUROCRYPT'13, a link between these two distinguishers has been presented. However, though being independent of the underling structure of the cipher, it is usually not useful for most known ID or ZC distinguishers. So despite the relevance of those attacks, the question of their equivalence or inequivalence has not been formally addressed so far in a constructive practical way. In this paper, we aim to bridge this gap in the understanding of the links between the ID and ZC properties. We tackle this problem at the example of two wide classes of ciphers, namely, Feistel- and Skipjack-type ciphers. As our major contribution, for those ciphers, we derive conditions for impossible differentials and zero-correlation approximations to cover the same number of rounds. Using the conditions, we prove an equivalence between ID and ZC distinguishers for type-I and type-II Feistel- type ciphers, for Rule-A and Rule-B Skipjack-type ciphers, as well as for TWINE and LBlock. Moreover, we show this equivalence for the Extended Generalised Feistel construction presented at SAC'13. We also use our theoretical results to argue for an inequivalence between ID and ZC distinguishers for a range of Skipjack-type ciphers.\",\n \"Title: Cryptanalysis of the Full MMB Block Cipher\\nYear: 2009\\n\\nAbstract: The block cipher MMB was designed by Daemen, Govaerts and Vandewalle, in 1993, as an alternative to the IDEA block cipher. We exploit and describe unusual properties of the modular multiplication in ${\\\\mathbb Z}_{2^{32}-1}$, which lead to a differential attack on the full 6-round MMB cipher (both versions 1.0 and 2.0). Further contributions of this paper include detailed square and linear cryptanalysis of MMB. Concerning differential cryptanalysis (DC), we can break the full MMB with 2118 chosen plaintexts, 295.91 6-round MMB encryptions and 264 counters, effectively bypassing the cipher's countermeasures against DC. For the square attack, we can recover the 128-bit user key for 4-round MMB with 234 chosen plaintexts, 2126.32 4-round encryptions and 264 memory blocks. Concerning linear cryptanalysis, we present a key-recovery attack on 3-round MMB requiring 2114.56 known-plaintexts and 2126 encryptions. Moreover, we detail a ciphertext-only attack on 2-round MMB using 293.6 ciphertexts and 293.6 parity computations. These attacks do not depend on weak-key or weak-subkey assumptions, and are thus independent of the key schedule algorithm.\",\n \"Title: Linear (Hull) and Algebraic Cryptanalysis of the Block Cipher PRESENT\\nYear: 2009\\n\\nAbstract: The contributions of this paper include the first linear hull and a revisit of the algebraic cryptanalysis of reduced-round variants of the block cipher PRESENT, under known-plaintext and ciphertext-only settings. We introduce a pure algebraic cryptanalysis of 5-round PRESENT and in one of our attacks we recover half of the bits of the key in less than three minutes using an ordinary desktop PC. The PRESENT block cipher is a design by Bogdanov et al. , announced in CHES 2007 and aimed at RFID tags and sensor networks. For our linear attacks, we can attack 25-round PRESENT with the whole code book, 296.68 25-round PRESENT encryptions, 240 blocks of memory and 0.61 success rate. Further we can extend the linear attack to 26-round with small success rate. As a further contribution of this paper we computed linear hulls in practice for the original PRESENT cipher, which corroborated and even improved on the predicted bias (and the corresponding attack complexities) of conventional linear relations based on a single linear trail.\",\n \"Title: A model for structure attacks, with applications to PRESENT and serpent\\nYear: 2012\\n\\nAbstract: As a classic cryptanalytic method for block ciphers, hash functions and stream ciphers, many extensions and refinements of differential cryptanalysis have been developed. In this paper, we focus on the use of so-called structures in differential attacks, i.e. the use of multiple input and one output difference. We give a general model and complexity analysis for structure attacks and show how to choose the set of differentials to minimize the time and data complexities. Being a subclass of multiple differential attacks in general, structure attacks can also be analyzed in the model of Blondeau et al. from FSE 2011. In this very general model, a restrictive condition on the set of input differences is required for the complexity analysis. We demonstrate that in our dedicated model for structure attacks, this condition can be relaxed, which allows us to consider a wider range of differentials. Finally, we point out an inconsistency in the FSE 2011 attack on 18 rounds of the block cipher PRESENT and use our model for structure attacks to attack 18-round PRESENT and improve the previous structure attacks on 7-round and 8-round Serpent. To the best of our knowledge, those attacks are the best known differential attacks on these two block ciphers.\",\n \"Title: New Linear Cryptanalytic Results of Reduced-Round of CAST-128 and CAST-256\\nYear: 2008\\n\\nAbstract: This paper presents a linear cryptanalysis for reduced round variants of CAST-128 and CAST-256 block ciphers. Compared with the linear relation of round function with the bias 2驴 17 by J. Nakahara et al., we found the more heavily biased linear approximations for 3 round functions and the highest one is 2驴 12.91. We can mount the known-plaintext attack on 6-round CAST-128 and the ciphertext-only attack on 4-round CAST-128. Moreover the known-plaintext attack on 24-round CAST-256 with key size 192 and 256 bits has been given, and the ciphertext-only attack on 21-round CAST-256 with key size 192 and 256 bits can be performed. At the same time, we also present the attack on 18-round CAST-256 with key size 128 bits.\",\n \"Title: Algebraic techniques in differential cryptanalysis revisited\\nYear: 2011\\n\\nAbstract: At FSE 2009, Albrecht et al. proposed a new cryptanalytic method that combines algebraic and differential cryptanalysis. They introduced three new attacks, namely Attack A, Attack B and Attack C. For Attack A, they explain that the time complexity is difficult to determine. The goal of Attacks B and C is to filter out wrong pairs and then recover the key. In this paper, we show that Attack C does not provide an advantage over differential cryptanalysis for typical block ciphers, because it cannot be used to filter out any wrong pairs that satisfy the ciphertext differences. Furthermore, we explain why Attack B provides no advantage over differential cryptanalysis for PRESENT. We verify our results for PRESENT experimentally, using both PolyBoRi and MiniSat. Our work helps to understand which equations are important in the differential-algebraic attack. Based on our findings, we present two new differential-algebraic attacks. Using the first method, our attack on 15-round PRESENT-80 requires 259 chosen plaintexts and has a worstcase time complexity of 273.79 equivalent encryptions. Our new attack on 14-round PRESENT-128 requires 255 chosen plaintexts and has a worstcase time complexity of 2112.83 equivalent encryptions. Although these attacks have a higher time complexity than the differential attacks, their data complexity is lower.\",\n \"Title: New Differential Cryptanalytic Results For Reduced-Round Cast-128\\nYear: 2010\\n\\nAbstract: CAST 128 is a block cipher used in a number of products notably as the default cipher in some versions of GPG and PGP It has been approved for Canadian government use by the Communications Security Establishment Haruki Seki et al found 2 round differential characteristics and they can attack 5 round CAST 128 In this paper we studied the prop ernes of round functions F-1 and F-3 in CAST 128 and identified differential characteristics for F-1 round function and F-3 round function So we identified a 6 round differential characteristic with probability 2(-53) under 2(-23) (8) of the total key space Then based on 6 round differential characteristic we can attack 8 round CAST 128 with key sizes greater than or equal to 72 bits and 9 round CAST 128 with key sizes greater than or equal to 104 bits We give the summary of attacks on reduced round CAST 128 in Table 10\",\n \"Title: New impossible differential attack on SAFER+ and SAFER ++\\nYear: 2012\\n\\nAbstract: SAFER+ was a candidate block cipher for AES with 128-bit block size and a variable key sizes of 128, 192 or 256 bits. Bluetooth uses customized versions of SAFER+ for security. The numbers of rounds for SAFER+ with key sizes of 128, 192 and 256 are 8, 12 and 16, respectively. SAFER++, a variant of SAFER+, was among the cryptographic primitives selected for the second phase of the NESSIE project. The block size is 128 bits and the key size can take either 128 or 256 bits. The number of rounds for SAFER++ is 7 for keys of 128 bits, and 10 for keys of 256 bits. Both ciphers use PHT as their linear transformation. In this paper, we take advantage of properties of PHT and S-boxes to identify 3.75-round impossible differentials for SAFER++ and 2.75-round impossible differentials for SAFER+, which result in impossible differential attacks on 4-round SAFER+/128(256), 5-round SAFER++/128 and 5.5-round SAFER++/256. Our attacks significantly improve previously known impossible differential attacks on 3.75-round SAFER +/128(256) and SAFER++/128(256). Our attacks on SAFER +/128(256) and SAFER++/128(256) represent the best currently known attack in terms of the number of rounds. © 2013 Springer-Verlag.\",\n \"Title: Constructing Mixed-integer Programming Models whose Feasible Region is Exactly the Set of All Valid Differential Characteristics of SIMON.\\nYear: 2015\\n\\nAbstract: In IACR ePrint 2014/747, a method for constructing mixed- integer linear programming (MILP) models whose feasible regions are exactly the sets of all possible dierential (or linear) characteristics for a wide range of block ciphers is presented. These models can be used to search for or enumerate dierential\",\n \"Title: Equivalent Key Recovery Attacks Against HMAC and NMAC with Whirlpool Reduced to 7 Rounds.\\nYear: 2015\\n\\nAbstract: A main contribution of this paper is an improved analysis against HMAC instantiating with reduced Whirlpool. It recovers equivalent keys, which are often denoted as K-in and K-out, of HMAC with 7-round Whirlpool, while the previous best attack can work only for 6 rounds. Our approach is applying the meet-in-the-middle (MITM) attack on AES to recover MAC keys of Whirlpool. Several techniques are proposed to bypass different attack scenarios between a block cipher and a MAC, e.g., the chosen plaintext model of the MITM attacks on AES cannot be used for HMAC-Whirlpool. Besides, a larger state size and different key schedule designs of Whirlpool leave us a lot of room to study. As a result, equivalent keys of HMAC with 7-round Whirlpool are recovered with a complexity of (Data, Time, Memory) = (2(481.7), 2(482.3), 2(481)).\",\n \"Title: Improved Linear Cryptanalysis of CAST-256.\\nYear: 2014\\n\\nAbstract: CAST-256, a first-round AES (Advanced Encryption Standard) candidate, is designed based on CAST-128. It is a 48-round Generalized-Feistel-Network cipher with 128-bit block accepting 128, 160, 192, 224 or 256 bits keys. Its S-boxes are non-surjective with 8-bit input and 32-bit output. Wang et al. identified a 21-round linear approximation and gave a key recovery attack on 24-round CAST-256. In ASIACRYPT 2012, Bogdanov et al. presented the multidimensional zero-correlation linear cryptanalysis of 28 rounds of CAST-256. By observing the property of the concatenation of forward quad-round and reverse quad-round and choosing the proper active round function, we construct a linear approximation of 26-round CAST-256 and recover partial key information on 32 rounds of CAST-256. Our result is the best attack according to the number of rounds for CAST-256 without weak-key assumption so far.\",\n \"Title: Integral Zero-Correlation Distinguisher For Arx Block Cipher, With Application To Shacal-2\\nYear: 2014\\n\\nAbstract: At ASIACRYPT' 12, Bogdanov et al. revealed the identity of integral distinguishers and zero-correlation linear approximations where the mask consists of two parts: one part should take any non-zero value and the other part should be fixed to zero. For zero-correlation linear approximations of some ARX block ciphers, one bit of input mask usually is fixed to one, which do not conform to zero-correlation linear approximations considered by Bogdanov et al.. Can they also be converted to an integral distinguisher? In this paper, we show that such zero-correlation linear approximations can be transformed to an integral distinguisher too. As an application, we give the attack on SHACAL-2 which is one of the four selected block ciphers by NESSIE. Namely, a attack on 32-round SHACAL-2 is reported. As an integral attack, our attack is much better than the previous integral attack on 28-round SHACAL-2 in terms of the number of rounds. In the classical single-key setting, our attack could break as many rounds as the previous best attack, but with significant improvements in data complexity and memory complexity.\",\n \"Title: Integrals go Statistical: Cryptanalysis of Full Skipjack Variants.\\nYear: 2016\\n\\nAbstract: Integral attacks form a powerful class of cryptanalytic techniques that have been widely used in the security analysis of block ciphers. The integral distinguishers are based on balanced properties holding with probability one. To obtain a distinguisher covering more rounds, an attacker will normally increase the data complexity by iterating through more plaintexts with a given structure under the strict limitation of the full codebook. On the other hand, an integral property can only be deterministically verified if the plaintexts cover all possible values of a bit selection. These circumstances have somehow restrained the applications of integral cryptanalysis. In this paper, we aim to address these limitations and propose a novel statistical integral distinguisher where only a part of value sets for these input bit selections are taken into consideration instead of all possible values. This enables us to achieve significantly lower data complexities for our statistical integral distinguisher as compared to those of traditional integral distinguisher. As an illustration, we successfully attack the full-round Skipjack-BABABABA for the first time, which is the variant of NSA's Skipjack block cipher.\",\n \"Title: Linear cryptanalysis of reduced-round SPECK\\nYear: 2016\\n\\nAbstract: SPECK is a family of lightweight block ciphers which was proposed by United States National Security Agency and designed for optimal performance in software. The paper gives the security of SPECK against linear cryptanalysis and introduces 9, 10, 12, 15 and 16 rounds linear approximations on SPECK for block sizes of 32, 48, 64, 96 and 128 bits, respectively. Partial linear mask table is used to speed up the search progress rather than the linear mask table. Using the structure of red-black tree to store the pLMT, we deduce the search time. Combining the Segment Searching with branch-and-bound method, the search time is further reduced. For 48-, 96- and 128-bit version the lengths of the linear approximations are 1, 9 and 10 rounds longer than the previous linear cryptanalytic. For SPECK64 the correlation of the linear approximation is twice as much as the previous linear cryptanalytic. As a result, we improve the previous linear cryptanalysis and gain more obvious advantage for block lengths of 96 and 128 bits. Especially, in aspect of SPECK96/144, SPECK128/192 and SPECK128/256 we can attack the same rounds as the best previous attacks. A new search method for linear approximations of the SPECK family.The best known linear approximations of the SPECK family.The best Linear attack on SPECK96 and SPECK128.The same round numbers on SPECK96 and SPECK128 as the best key recovery attack.\",\n \"Title: New Impossible Differential Attack On Safer Block Cipher Family\\nYear: 2015\\n\\nAbstract: SAFER block cipher family consists of SAFER K, SAFER SK, SAFER+ and SAFER++. As the first proposed block cipher of them, SAFER K is strengthened by SAFER SK with improved key schedule. SAFER+ is designed as an AES candidate and Bluetooth uses a customized version of it for security. SAFER++, a variant of SAFER+, is among the cryptographic primitives selected for the second phase of the NESSIE project. In this paper, we take advantage of properties of the linear transformation and S-boxes to identify new impossible differentials for SAFER SK, SAFER+, and SAFER++. Moreover, we give the impossible differential attacks on 4-round SAFER SK/128 and 4-round SAFER+/128(256), 5-round SAFER++/128 and 5.5-round SAFER++/256. Our attacks significantly improve previously known impossible differential attacks on them. Specifically, our attacks on SAFER+ are the best attack in terms of number of rounds.\",\n \"Title: Extending the Applicability of the Mixed-Integer Programming Technique in Automatic Differential Cryptanalysis\\nYear: 2015\\n\\nAbstract: We focus on extending the applicability of the mixed-integer programming MIP based method in differential cryptanalysis such that more work can be done automatically. Firstly, we show how to use the MIP-based technique to obtain almost all high probability 2-round iterative related-key differential characteristics of PRIDE a block cipher proposed in CRYPTO 2014 automatically by treating the $$g_i^{j}\\\\\\\\cdot $$gijï¾ź function with a special kind of modulo addition operations in the key schedule algorithm of PRIDE as an $$8 \\\\\\\\times 8$$8×8 S-box and partially modelling its differential behavior with linear inequalities. Note that some of the characteristics presented in this paper has not been found before, and all the characteristics we found can be used to attack the full-round PRIDE in the related-key model. Secondly, we show how to construct MIP models whose feasible regions are exactly the sets of all possible differential characteristics of SIMON a family of lightweight block ciphers designed by the U.S. National Security Agency. With this method, there is no need to filter out invalid characteristics due to the dependent inputs of the AND operations. Finally, we present an MIP-based method which can be used to automatically analyze how the differences at the beginning and end of a differential distinguisher propagate upwards and downward. Note that how the differences at the ends of a differential distinguisher propagate, together with the probability of the differential distinguisher, determine how many outer rounds can be added to the distinguisher, which key bits can be recovered without exhaustive search, and how to identify wrong pairs in the filtering process. We think this work serves to further strengthens the position of the MIP as a promising tool in automatic differential cryptanalysis.\",\n \"Title: MILP-Based Automatic Search Algorithms for Differential and Linear Trails for Speck.\\nYear: 2016\\n\\nAbstract: In recent years, Mixed Integer Linear Programming MILP has been successfully applied in searching for differential characteristics and linear approximations in block ciphers and has produced the significant results for some ciphers such as SIMON a family of lightweight and hardware-optimized block ciphers designed by NSA etc. However, in the literature, the MILP-based automatic search algorithm for differential characteristics and linear approximations is still infeasible for block ciphers such as ARX constructions. In this paper, we propose an MILP-based method for automatic search for differential characteristics and linear approximations in ARX ciphers. By researching the properties of differential characteristic and linear approximation of modular addition in ARX ciphers, we present a method to describe the differential characteristic and linear approximation with linear inequalities under the assumptions of independent inputs to the modular addition and independent rounds. We use this representation as an input to the publicly available MILP optimizer Gurobi to search for differential characteristics and linear approximations for ARX ciphers. As an illustration, we apply our method to Speck, a family of lightweight and software-optimized block ciphers designed by NSA, which results in the improved differential characteristics and linear approximations compared with the existing ones. Moreover, we provide the improved differential attacks on Speck48, Speck64, Speck96 and Speck128, which are the best attacks on them in terms of the number of rounds.\",\n \"Title: Improved Zero-Correlation Cryptanalysis on SIMON.\\nYear: 2015\\n\\nAbstract: SIMON is a family of lightweight block ciphers publicly released by the NSA. Up to now, there have been many cryptanalytic results on it by means of differential, linear, impossible differential, integral, zero-correlation linear cryptanalysis and so forth. At INDOCRYPT 2014, Wang et al. gave zero-correlation attacks for 20-round SIMON32, 20-round SIMON48/72 and 21-round SIMON48/96. We investigate the security of whole family of SIMON by using zero-correlation linear cryptanalysis in this paper. For SIMON32 and SIMON48, we can attack one more round than the previous zero-correlation attacks given by Wang et al. We are the first one to give zero-correlation linear approximations of SIMON64, SIMON96 and SIMON128. These approximations are also utilized to attack the corresponding ciphers.\",\n \"Title: Improved Differential Cryptanalysis of CAST-128 and CAST-256.\\nYear: 2016\\n\\nAbstract: CAST-128 and CAST-256 are two symmetric algorithms designed by Adams in 1990s. Both of them adopt the CAST design procedure which makes them process a number of desirable cryptographic. CAST-128 is notably used as the default cipher in some versions of GNU Privacy Guard (GPG) and Pretty Good Privacy (PGP) systems. As an extension of CAST-128, CAST-256 was submitted as a candidate for the Advanced Encryption Standard (AES). Since they are widely used, there are many different attacks on them. Differential cryptanalysis is one of the most powerful tools. In this paper, we achieve improved differential cryptanalysis of both CAST-128 and CAST-256 based on the technique of accessing differential tables. Firstly, we propose a differential attack on 9-round CAST-128 with (2^{73}) encryptions and (2^{58}) chosen plaintexts. Although we cannot improve the number of attacked rounds, the time complexity is significantly reduced. Then we mount an improved differential attack on 10 quad-rounds of modified CAST-256 which increase one quad-round than previous attack. The time complexity of this attack is (2^{217}) encryptions, and the data complexity is (2^{123}) chosen plaintexts. As far as we know, these are the best known attacks on CAST-128 and CAST-256 under weak key assumption.\",\n \"Title: Cryptanalysis of round-reduced ASCON.\\nYear: 2017\\n\\nAbstract: ASCON是CAESAR竞赛的候选认证加密算法之一。在CT-RSA 2015上, 其设计者恢复了含有6轮初始化阶段的ASCON算法的密钥, 并给出了3/4轮的标签生成阶段的伪造攻击, 该伪造需求2^33/2^101个消息。这篇论文对包含7轮初始化阶段和5轮明文处理阶段的简化版ASCON算法执行密钥恢复攻击。除此之外, 我们对4/5/6轮的标签生成阶段建立了伪造, 所需数据量为2^9/2^17/2^33。该伪造相对之前具有实际攻击复杂度。\",\n \"Title: New Linear Cryptanalysis of Chinese Commercial Block Cipher Standard SM4.\\nYear: 2017\\n\\nAbstract: SM4 is a Chinese commercial block cipher standard used for wireless communication in China. In this paper, we use the partial linear approximation table of S-box to search for three rounds of iterative linear approximations of SM4, based on which the linear approximation for 20-round SM4 has been constructed. However, the best previous identified linear approximation only covers 19 rounds. At the same time, a linear approximation for 19-round SM4 is obtained, which is better than the known results. Furthermore, we show the key recovery attack on 24-round SM4 which is the best attack according to the number of rounds.\",\n \"Title: Statistical integral attack on CAST-256 and IDEA.\\nYear: 2018\\n\\nAbstract: Integral attack, as a powerful technique in the cryptanalysis field, has been widely utilized to evaluate the security of block ciphers. Integral distinguisher is based on balanced property on output with probability one. To obtain a distinguisher covering more rounds, an attacker will usually increase the data complexity by iterating through all values of more bits of plaintexts under the firm limitation that the data complexity should be less than the whole plaintext space. In order to release the limitation and reduce the data complexity, Wang et al. proposed a statistical integral distinguisher at FSE’16. In this paper, we exploit the statistical integral distinguisher to attack the IDEA and CAST-256 block ciphers. As a result, we manage to mount a key recovery attack on 29-round CAST-256 with 2 chosen plaintexts, 2 encryptions and 2 bytes of memory. By making a trade-off between the time complexity and data complexity, the attack can be achieved by 2 chosen plaintexts, 2 encryptions and 2 bytes of memory. As far as we know, these are the best attacks on CAST-256 in the single-key model without weak-key assumption so far. What’s more, we find an integral distinguisher of IDEA block cipher, which is the longest integral distinguisher known to now. By taking advantage of this distinguisher, we achieve a key recovery attack on 4.5-round IDEA with 2 known plaintexts, 2 encryptions and 2 bytes of memory respectively. It is the best integral attack with respect to the number of rounds.\",\n \"Title: Statistical integral distinguisher with multi-structure and its application on AES-like ciphers.\\nYear: 2018\\n\\nAbstract: Integral attack is one of the most powerful tools in the field of symmetric ciphers. In order to reduce the time complexity of original integral one, Wang et al. firstly proposed a statistical integral distinguisher at FSE’16. However, they don’t consider the cases that there are several integral properties on output and multiple structures of data should be used at the same time. In terms of such cases, we put forward a new statistical integral distinguisher, which enables us to reduce the data complexity comparing to the traditional integral ones under multiple structures. As illustrations, we use it into the known-key distinguishers on AES-like ciphers including AES and the permutations of Whirlpool, PHOTON and Grøstl-256 hash functions based on the Gilbert’s work at ASIACRYPT’14. These new distinguishers are the best ones comparing with previous ones under known-key setting. Moreover, we propose a secret-key distinguisher on 5-round AES under chosen-ciphertext mode. Its data, time and memory complexities are 2 chosen ciphertexts, 2 encryptions and 2 blocks. This is the best integral distinguisher on AES with secret S-box under secret-key setting so far.\",\n \"Title: Zero-correlation attacks: statistical models independent of the number of approximations.\\nYear: 2018\\n\\nAbstract: Multiple and multidimensional zero-correlation linear cryptanalysis have been two of the most powerful cryptanalytic techniques for block ciphers, and it has been shown that the differentiating factor of these two statistical models is whether distinct plaintexts are assumed or not. Nevertheless, questions remain regarding how these analyses can be universalized without any limitations and can be used to accurately estimate the data complexity and the success probability. More concretely, the current models for multiple zero-correlation (MPZC) and multidimensional zero-correlation (MDZC) cryptanalysis are not valid in the setting with a limited number of approximations and the accuracy of the estimation for data complexity can not be guaranteed. Besides, in a lot of cases, using too many approximations may cause an exhaustive search when we want to launch key-recovery attacks. In order to generalize the original models using the normal approximation of the -distribution, we provide a more accurate approach to estimate the data complexity and the success probability for MPZC and MDZC cryptanalysis without such approximation. Since these new models directly rely on the -distribution, we call them the MPZC and MDZC models. An interesting thing is that the chi-square-multiple zero-correlation (-MPZC) model still works even though we only have a single zero-correlation linear approximation. This fact puts an end to the situation that the basic zero-correlation linear cryptanalysis requires the full codebook under the known-plaintext attack setting. As an illustration, we apply the -MPZC model to analyze TEA and XTEA. These new attacks cover more rounds than the previous MPZC attacks. Moreover, we reconsider the multidimensional zero-correlation (MDZC) attack on 14-round CLEFIA-192 by utilizing less zero-correlation linear approximations. In addition, some other ciphers which already have MDZC analytical results are reevaluated and the data complexities under the new model are all less than or equal to those under the original model. Some experiments are conducted in order to verify the validity of the new models, and the experimental results convince us that the new models provide more precise estimates of the data complexity and the success probability.\",\n \"Title: Cryptanalysis Of Aes-Prf And Its Dual\\nYear: 2018\\n\\nAbstract: A dedicated pseudorandom function (PRF) called AES-PRF was proposed by Mennink and Neves at FSE 2018 (ToSC 2017, Issue 3). AES-PRF is obtained from AES by using the output of the 5-th round as the feed-forward to the output state. This paper presents extensive security analysis of AES-PRF and its variants. Specifically, we consider unbalanced variants where the output of the s-th round is used as the feed-forward. We also analyze the security of \\\"dual\\\" constructions of the unbalanced variants, where the input state is used as the feed-forward to the output of the s-th round. We apply an impossible differential attack, zero-correlation linear attack, traditional differential attack, zero correlation linear distinguishing attack and a meet-in-the-middle attack on these PRFs and reduced round versions. We show that AES-PRF is broken whenever a <= 2 or s >= 6, or reduced to 7 rounds, and Dual-AES-PRF is broken whenever s <= 4 or s >= 8. Our results on AES-PRF improve the initial security evaluation by the designers in various ways, and our results on Dual-AES-PRF give the first insight to its security.\",\n \"Title: New Distinguisher On Reduced-Round Keccak Sponge Function\\nYear: 2019\\n\\nAbstract: The security analysis of Keccak, the winner of SHA-3, has attracted considerable interest. Recently, some attention has been paid to distinguishing Keccak sponge function from random permutation. In EUROCRYPT'17, Huang et al. proposed conditional cube tester to recover the key of Keccak-MAC and Keyak and to construct practical distinguishing attacks on Keccak sponge function up to 7 rounds. In this paper, we improve the conditional cube tester model by refining the formulation of cube variables. By classifying cube variables into three different types and working the candidates of these types of cube variable carefully, we are able to establish a new theoretical distinguisher on 8-round Keccak sponge function. Our result is more efficient and greatly improves the existing results. Finally we remark that our distinguishing attack on the the reduced-round Keccak will not threat the security margin of the Keccak sponge function.\",\n \"Title: More Accurate Differential Properties Of Led64 And Midori64\\nYear: 2018\\n\\nAbstract: In differential cryptanalysis, a differential is more valuable than the single trail belonging to it in general. The traditional way to compute the probability of the differential is to sum the probabilities of all trails within it. The automatic tool for the search of differentials based on Mixed Integer Linear Programming (MILP) has been proposed and realises the task of finding multiple trails of a given differential. The problem is whether it is reliable to evaluate the probability of the differential traditionally. In this paper, we focus on two lightweight block ciphers - LED64 and Midori64 and show the more accurate estimation of differential probability considering the key schedule. Firstly, an automated tool based on Boolean Satisfiability Problem (SAT) is put forward to accomplish the automatic search of differentials for ciphers with S-boxes and is applied to LED64 and Midori64. Secondly, we provide an automatic approach to detect the right pairs following a given differential, which can be exploited to calculate the differential property. Applying this technique to the STEP function of LED64, we discover some differentials with enhanced probability. As a result, the previous attacks relying upon high probability differentials can be improved definitely. Thirdly, we present a method to compute an upper-bound of the weak-key ratio for a given differential, which is utilised to analyse 4-round differentials of Midori64. We detect two differentials whose weak-key ratios are much lower than the expected 50%. More than 78% of the keys will make these two differentials being impossible differentials. The idea of the estimation for an upper-bound of the weak-key ratio can be employed for other ciphers and allows us to launch differential attacks more reliably. Finally, we introduce how to compute the enhanced differential probability and evaluate the size of keys achieving the improved probability. Such a property may incur an efficient weak-key attack. For a 4-round differential of Midori64, we obtain an improved differential property for a portion of keys.\",\n \"Title: Automatic Search for a Variant of Division Property Using Three Subsets.\\nYear: 2019\\n\\nAbstract: The division property proposed at Eurocrypt’15 is a novel technique to find integral distinguishers, which has been applied to most kinds of symmetric ciphers such as block ciphers, stream ciphers, and authenticated encryption, etc. The original division property is word-oriented, and later the bit-based one was proposed at FSE’16 to get better integral property, which is composed of conventional bit-based division property (two-subset division property) and bit-based division property using three subsets (three-subset division property). Three-subset division property has more potential to achieve better integral distinguishers compared with the two-subset division property. The bit-based division property could not be to apply to ciphers with large block sizes due to its unpractical complexity. At Asiacrypt’16, the two-subset division property was modeled using Mixed Integral Linear Programming (MILP) technique, and the limits of block sizes were eliminated. However, there is still no efficient method searching for three-subset division property. The propagation rule of the XOR operation for (mathbb {L}) (The definition of (mathbb {L}) and (mathbb {K}) is introduced in Sect. 2.), which is a set used in the three-subset division property but not in two-subset one, requires to remove some specific vectors, and new vectors generated from (mathbb {L}) should be appended to (mathbb {K}) when Key-XOR operation is applied, both of which are difficult for common automatic tools such as MILP, SMT or CP. In this paper, we overcome one of the two challenges, concretely, we address the problem to add new vectors into (mathbb {K}) from (mathbb {L}) in an automatic search model. Moreover, we present a new model automatically searching for a variant three-subset division property (VTDP) with STP solver. The variant is weaker than the original three-subset division property (OTDP) but it is still powerful in some ciphers. Most importantly, this model has no constraints on the block size of target ciphers, which can also be applied to ARX and S-box based ciphers. As illustrations, some improved integral distinguishers have been achieved for SIMON32, SIMON32/48/64(102), SPECK32 and KATAN/KTANTAN32/48/64 according to the number of rounds or number of even/odd-parity bits.\",\n \"Title: Linear cryptanalysis of reduced-round ICEBERG\\nYear: 2012\\n\\nAbstract: ICEBERG is proposed by Standaert et al. in FSE 2004 for reconfigurable hardware implementations. ICEBERG is a fast involutional SPN block cipher and all its components are involutional and allow very efficient combinations of encryption/decryption. ICEBERG uses 64-bit block size and 128-bit key and the round number is 16. In this paper, we firstly find the best linear approximation of 6-round ICEBERG. We find that 2122 of ICEBERG keys are weak for linear cryptanalysis, and the linear deviation can be strengthened more heavily than the linear characteristic by the multi-path effect(Linear Hull). And we discover a 6-round linear hull consisting of 7 linear characteristics with a linear deviation of 2−29.99. Then we give a linear attack against 7-round ICEBERG for the weak keys.\",\n \"Title: A SVD-based 2DOMP algorithm for compressed image sensing\\nYear: 2018\\n\\nAbstract: We use the singular value decomposition of the separable measurement matrices to obtain the optimized separable reconstruction matrices and optimize the measurements. A two-dimensional orthogonal matching pursuit optimization algorithm based on singular value decomposition is proposed. Numerical experiments demonstrate that our proposed 2DOMP-SVD algorithm can significantly improve reconstruction quality and signal to noise ratio. Moreover, separable imaging operator arise naturally in many optical implementations and can satisfy the requirements for both the measurement matrix and the reconstruction matrix individually. And this design is suitable for general separable linear system.\",\n \"Title: New integral attacks on SIMON.\\nYear: 2017\\n\\nAbstract: SIMON is a family of lightweight block ciphers publicly released by National Security Agency (NSA). Up to now, there have been many cryptanalytic results on it by means of impossible differential, integral, zero-correlation linear cryptanalysis and so forth. In this study, the authors analyse the characteristic of the Boolean functions of SIMON32 and find that the presentation of zero-sum property...\",\n \"Title: Conditional Cube Attack on Reduced-Round Keccak Sponge Function.\\nYear: 2017\\n\\nAbstract: The security analysis of Keccak, the winner of SHA-3, has attracted considerable interest. Recently, some attention has been paid to the analysis of keyed modes of Keccak sponge function. As a notable example, the most efficient key recovery attacks on Keccak-MAC and Keyak were reported at EUROCRYPT'15 where cube attacks and cube-attack-like cryptanalysis have been applied. In this paper, we develop a new type of cube distinguisher, the conditional cube tester, for Keccak sponge function. By imposing some bit conditions for certain cube variables, we are able to construct cube testers with smaller dimensions. Our conditional cube testers are used to analyse Keccak in keyed modes. For reduced-round Keccak-MAC and Keyak, our attacks greatly improve the best known attacks in key recovery in terms of the number of rounds or the complexity. Moreover, our new model can also be applied to keyless setting to distinguish Keccak sponge function from random permutation. We provide a searching algorithm to produce the most efficient conditional cube tester by modeling it as an MILP (mixed integer linear programming) problem. As a result, we improve the previous distinguishing attacks on Keccak sponge function significantly. Most of our attacks have been implemented and verified by desktop computers. Finally we remark that our attacks on the reduced-round Keccak will not threat the security margin of Keccak sponge function.\",\n \"Title: Related-Tweak Statistical Saturation Cryptanalysis And Its Application On Qarma\\nYear: 2019\\n\\nAbstract: Statistical saturation attack takes advantage of a set of plaintext with some bits fixed while the others vary randomly, and then track the evolution of a non-uniform plaintext distribution through the cipher. Previous statistical saturation attacks are all implemented under single-key setting, and there is no public attack models under related-key/tweak setting. In this paper, we propose a new cryptanalytic method which can be seen as related-key/tweak statistical saturation attack by revealing the link between the related-key/tweak statistical saturation distinguishers and KDIB (Key Difference Invariant Bias) / TDIB (Tweak Difference Invariant Bias) ones. KDIB cryptanalysis was proposed by Bogdanov et al. at ASIACRYPT'13 and utilizes the property that there can exist linear trails such that their biases are deterministically invariant under key difference. And this method can be easily extended to TDIB distinguishers if the tweak is also alternated. The link between them provides a new and more efficient way to find related-key/tweak statistical saturation distinguishers in ciphers. Thereafter, an automatic searching algorithm for KDIB/TDIB distinguishers is also given in this paper, which can be implemented to find word-level KDIB distinguishers for S-box based key-alternating ciphers. We apply this algorithm to QARMA-64 and give related-tweak statistical saturation attack for 10-round QARMA-64 with outer whitening key. Besides, an 11-round attack on QARMA-128 is also given based on the TDIB technique. Compared with previous public attacks on QARMA including outer whitening key, all attacks presented in this paper are the best ones in terms of the number of rounds.\",\n \"Title: Automatic search method for multiple differentials and its application on MANTIS\\nYear: 2019\\n\\nAbstract: Multiple differential cryptanalysis is one of the extensions of classic differential cryptanalysis. In this paper, we present a generic automatic search method for clustering multiple differentials on a target block cipher. Our search method has two steps. Firstly, the sets of input and output differences will be determined. With these sets, we get different multiple differentials. Then for each one of these multiple differentials, we enumerate and record all satisfied differential trails, which leads to a more accurate evaluation of the multiple differentials distinguisher. Among these different multiple differentials distinguishers, we can choose the best one for key recovery attack. We demonstrate our search method by applying it on the part of differentials of the block cipher MANTIS. As a result, we find a new 10-round multiple differentials distinguisher with probability 2−55.98 and an 11-round multiple differentials distinguisher with probability 2−63.71, which is the longest distinguisher for MANTIS so far as we know. This new 10-round distinguisher can lead to a better signal-to-noise ratio, so we derive an improved key recovery attack on MANTIS-6 with the complexity of about 251.79 chosen-plaintext queries, 251.91 encryptions and data-time product 2103.70, which is better than the previous best one with data-time product 2110.61. Aiming at exploring the gap between the performance of multiple differential attack and the security margin on MANTIS, we also use the 11-round distinguisher to derive a key recovery attack on MANTIS-7 with the complexity of about 261.86 chosen-plaintext queries, 2102.92 encryptions and data-time product 2164.78. It does not threat the security of full version MANTIS (MANTIS-7) since the security bound of data-time product claimed by the designers is 2126.\",\n \"Title: Linear Cryptanalyses Of Three Aeads With Gift-128 As Underlying Primitives\\nYear: 2021\\n\\nAbstract: This paper considers the linear cryptanalyses of Authenticated Encryptions with Associated Data (AEADs) GIFT-COFB, SUNDAE-GIFT, and HyENA. All of these proposals take GIFT-128 as underlying primitives. The automatic search with the Boolean satisfiability problem (SAT) method is implemented to search for linear approximations that match the attack settings concerning these primitives. With the newly identified approximations, we launch key-recovery attacks on GIFT-COFB, SUNDAE-GIFT, and HyENA when the underlying primitives are replaced with 16-round, 17-round, and 16-round versions of GIFT-128. The resistance of GIFT-128 against linear cryptanalysis is also evaluated. We present a 24-round key-recovery attack on GIFT-128 with a newly obtained 19-round linear approximation. We note that the attack results in this paper are far from threatening the security of GIFT-COFB, SUNDAE-GIFT, HyENA, and GIFT-128.\",\n \"Title: Forced Independent Optimized Implementation of 4-Bit S-Box\\nYear: 2021\\n\\nAbstract: Searching the optimal circuit implementation of a Boolean function is still an open problem. This work proposes a new optimizing scheme, which could find circuit expressions with optimal gate equivalent complexity (GEC) using SAT solvers under a depth-L framework. To obtain a better GEC performance in the optimizing scheme, we first propose the ternary and area profile models for SAT problems. The former introduces multiple efficient 3-input logic gates, and the latter takes the different weights of various gates into account in solving. To demonstrate the validity and usefulness, we use our optimizing methodology to search optimized implementation of a given 4-bit S-box with the forced independent property. For an S-box hardware implementation, its forced independent property can ensure that no gate is shared between every two component-circuits, which is beneficial to prevent Differential Fault Analysis (DFA). Finally, we evaluate the implementation performances of two models (i.e., ternary and binary models) and two implementation approaches (i.e., Table-based and Boolean expression methods) by case studies covering several know S-boxes. The experimental results show that our models and approach have better area performance for the S-boxes with forced independence property in most instances.\",\n \"Title: Related-Tweakey Impossible Differential Attack On Qarma-128\\nYear: 2022\\n\\nAbstract: Dear editor,\\r\\nQARMA[1]is a family of hardware-oriented lightweight tweakable block ciphers designed by Avanzi.It contains two versions,which support block sizes of 64 and 128 bits,de-noted by QARMA-64 and QARMA-128,respectively.The structure of QARMA is an Even-Mansour scheme[2]with a keyed pseudo-reflector,and the TWEAKEY framework is taken as an inspiration.\",\n \"Title: A Column Generation Tailored To Electric Vehicle Routing Problem With Nonlinear Battery Depreciation\\nYear: 2022\\n\\nAbstract: Since the battery remains a significant cost component of electric vehicles (EVs), controlling the depreciation costs of EVs' batteries is of great importance, especially from the perspective of the electric vehicle routing problem (EVRP). However, most existing studies on the EVRP have not explicitly considered the battery depreciation in the cost function; instead, it has been treated as a linear function of an EV's travel distance or time. In fact, the depth-of-discharge (DOD) significantly affects the battery life and leads to a naturally nonlinear depreciation function, which can be used to calculate the battery life more accurately. In this paper, we adopt three battery depreciation methods to investigate and compare their influences on the EVRP with time windows (EVRPTW): (1) a nonlinear function of DOD; (2) a linear function of charge-discharge cycles; and (3) a linear function of total traveling distance. The first method is mainly studied, and the remaining two methods are verified as comparative analyses. Meanwhile, both full and partial charge policies are considered to formulate the problem. By combining the charging policies and battery depreciation methods, four mixed -integer programming models are formulated, aiming to minimize the total cost. To pursue exact solutions in acceptable computing time, a column generation algorithm (CG) that relies on four tailored labeling algorithms (LAs) is designed. The LAs are used to accelerate the calculation speed of the pricing problem. The most considerable difficulty of solving pricing problems lies in the complex endogenous relationships among recharging time, drivers' waiting time, battery state-of-charge (SOC), battery depreciation, battery rated capacity, and driving distance. The LAs need to find a tradeoff among them and generate the shortest paths. Given this, we design specific and elaborate resource extension functions (REFs) for the four models, respectively, which is an extension to Desaulniers et al. (2016). Although the REFs are intricate, they work well with the help of dominance rules. Benchmark instances are performed to verify the efficiencies of the CG and LAs, which shows that instances with 25-nodes are solvable. In computational studies, we find that models considering the DOD can increase the battery life and decrease the total cost by 9%-10%. Moreover, several insights for better management of EV fleets are obtained.\",\n \"Title: SAND: an AND-RX Feistel lightweight block cipher supporting S-box-based security evaluations\\nYear: 2022\\n\\nAbstract: We revisit designing AND-RX block ciphers, that is, the designs assembled with the most fundamental binary operations-AND, Rotation and XOR operations and do not rely on existing units. Likely, the most popular representative is the NSA cipher SIMON, which remains one of the most efficient designs, but suffers from difficulty in security evaluation. As our main contribution, we propose SAND, a new family of lightweight AND-RX block ciphers. To overcome the difficulty regarding security evaluation, SAND follows a novel design approach, the core idea of which is to restrain the AND-RX operations to be within nibbles. By this, SAND admits an equivalent representation based on a 4x8synthetic S-box (SSb). This enables the use of classical S-box-based security evaluation approaches. Consequently, for all versions of SAND, (a) we evaluated security bounds with respect to differential and linear attacks, and in both single-key and related-key scenarios; (b) we also evaluated security against impossible differential and zero-correlation linear attacks. This better understanding of the security enables the use of a relatively simple key schedule, which makes the ASIC round-based hardware implementation of SAND to be one of the state-of-art Feistel lightweight ciphers. As to software performance, due to the natural bitslice structure, SAND reaches the same level of performance as SIMON and is among the most software-efficient block ciphers.\",\n \"Title: Related-Tweakey Impossible Differential Attack on Reduced-Round SKINNY-AEAD M1/M3\\nYear: 2022\\n\\nAbstract: SKINNY-AEAD is one of the second-round candidates of the Lightweight Cryptography Standardization project held by NIST. SKINNY-AEAD M1 is the primary member of six SKINNY-AEAD schemes, while SKINNY-AEAD M3 is another member with a small tag. In the design document, only security analyses of their underlying primitive SKINNY-128-384 are provided. Besides, there are no valid third-party analyses on SKINNY-AEAD M1/M3 according to our knowledge. Therefore, this paper focuses on constructing the first third-party security analyses on them under a nonce-respecting scenario. By taking the encryption mode of SKINNY-AEAD into consideration and exploiting several properties of SKINNY, we can deduce some necessary constraints on the input and tweakey differences of related-tweakey impossible differential distinguishers. Under these constraints, we can find distinguishers suitable for mounting powerful tweakey recovery attacks. With the help of the automatic searching algorithms based on STP, we find some 14-round distinguishers. Based on one of these distinguishers, we mount a 20-round and an 18-round tweakey recovery attack on SKINNY-AEAD M1/M3. To the best of our knowledge, all these attacks are the best ones so far.\",\n \"Title: Integral Attacks on Pyjamask-96 and Round-Reduced Pyjamask-128\\nYear: 2022\\n\\nAbstract: In order to provide benefits in the areas of fully homomorphic encryption (FHE), multi-party computation (MPC), post-quantum signature schemes, or efficient masked implementations for side-channel resistance, reducing the number of multiplications has become a quite popular trend for the symmetric cryptographic primitive designs. With an aggressive design strategy exploiting the extremely simple and low-degree S-box and low number of rounds, Pyjamask, the fundamental block cipher of the AEAD with the same name, has the smallest number of AND gates per bit among all the existing block ciphers (except Low-MC or Rasta which work on unconventional plaintext/key sizes). Thus, although the AEAD Pyjamask stuck at the second round of the NIST lightweight cryptography standardization process, the block cipher Pyjamask itself still attracts a lot of attention. Not very unexpectedly, the low degree and the low number of rounds are the biggest weakness of Pyjamask. At FSE 2020, Dobraunig et al. successfully mounted an algebraic and higher-order differential attack on full Pyjamask-96, one member of the Pyjamask block cipher family. However, the drawback of this attack is that it has to use the full codebook, which makes the attack less appealing. In this paper, we take integral attacks as our weapon, which are also sensitive to the low degree. Based on a new 11-round integral distinguishes found by state-of-the-art detection techniques, and combined with the relationship between round keys that reduces the involved keys, we give the key recovery attack on the full Pyjamask-96 without the full codebook for the first time. Further, the algebraic and higher-order differential technique does not work for Pyjamask-128, the other member of the Pyjamask block cipher family. To better understand the security margin of Pyjamask-128, we present the first third-party cryptanalysis on Pyjamask-128 up to 11 out of 14 rounds.\",\n \"Title: An STP-based model toward designing S-boxes with good cryptographic properties\\nYear: 2022\\n\\nAbstract: The substitution box (S-box) is an important nonlinear component in most symmetric cryptosystems and thus should have good properties. Its difference distribution table (DDT) and linear approximation table (LAT) affect the security of the cipher against differential and linear cryptanalysis. In most previous work, differential uniformity and linearity of an S-box are two primary cryptographic properties to impact the resistance against differential and linear attacks. In some cases, the branch number and fixed point are also be considered. However, other important cryptographic properties such as the frequency of differential uniformity (resp. linearity) and the number of Bad Input and Bad Output (BIBO) patterns in DDT (resp. LAT) are often ignored. These properties substantially affect lightweight cryptography based on substitution bit permutation networks (SbPN) such as PRESENT, GIFT and RECTANGLE. This paper introduces a new method to search for S-boxes satisfying all above criteria simultaneously. In our strategy, we transform the process of searching for S-boxes under certain constraints on cryptographic properties into a satisfiability (SAT) problem. As applications, we use our new approach to search out 4-bit and 5-bit S-boxes with the same or better cryptographic properties compared with the S-boxes from well-known ciphers. Finally, we also utilize our method to verify a conjecture proposed by Boura et al. in the case of all 3-bit and 4-bit S-boxes. We propose a proposition and two corollaries to reduce the search space in this verification.\",\n \"Title: Cryptanalysis of the AEAD and hash algorithm DryGASCON\\nYear: 2022\\n\\nAbstract: The DryGASCON scheme was one of authenticated encryption (AE) algorithms submitted to the ongoing NIST Lightweight Cryptography Standardization Process. Such a competition aims to standardize lightweight cryptographic algorithms and determine lightweight AE schemes that are suitable for use in constrained environments suitable for several emerging areas in which highly-constrained devices are interconnected. This article deals with DryGASCON and aims to evaluate its security. The reasons for this choice are twofold. The first reason is related to its unique design. The second one is that no forgery cryptanalysis has been performed on it in the literature to the best of our knowledge. Specifically, this paper presents practical forgery attacks on DryGASCON by exploiting internal collisions of the underlying permutation. During our cryptanalysis, we investigate collisions and discuss how to find them. Next, we mounted forgery attacks on DryGASCON128 with an optimal probability 2− 13 for a class of weak keys and with certainty (optimal probability 1) for pairs of related keys. We show that the number of elements from the weak-key class depends on the size of the secret keys. In addition, we also find forgeries of DryGASCON256 in the related-key scenario. Forgery attacks succeeded without the reuse of nonce. Our results threaten the authenticity and robustness of DryGASCON. However, thanks to our analysis, we shed light on the causes of its weaknesses, and we manage to draw constructive conclusions and recommendations for future AE designs schemes, notably similar to DryGASCON.\",\n \"Title: Towards Low-Latency Implementation of Linear Layers\\nYear: 2022\\n\\nAbstract: Lightweight cryptography features a small footprint and/or low computational complexity. Low-cost implementations of linear layers usually play an important role in lightweight cryptography. Although it has been shown by Boyar et al. that finding the optimal implementation of a linear layer is a Shortest Linear Program (SLP) problem and NP-hard, there exist a variety of heuristic methods to search for near-optimal solutions. This paper considers the low-latency criteria and focuses on the heuristic search of lightweight implementation for linear layers. Most of the prior approach iteratively combines the inputs (of linear layers) to reach the output, which can be regarded as the forward search. To better adapt the low-latency criteria, we propose a new framework of backward search that attempts to iteratively split every output (into an XORing of two bits) until all inputs appear. By bounding the time of splitting, the new framework can find a sub-optimal solution with a minimized depth of circuits. We apply our new search algorithm to linear layers of block ciphers and find many low-latency candidates for implementations. Notably, for AES Mixcolumns, we provide an implementation with 103 XOR gates with a depth of 3, which is among the best hardware implementations of the AES linear layer. Besides, we obtain better implementations in XOR gates for 54.3% of 4256 Maximum Distance Separable (MDS) matrices proposed by Li et al. at FSE 2019. We also achieve an involutory MDS matrix (in M-4(GL(8, F-2))) whose implementation uses the lowest number (i.e., 86, saving 2 from the state-of-the-art result) of XORs with the minimum depth.\",\n \"Title: Addendum to Linear Cryptanalyses of Three AEADs with GIFT-128 as Underlying Primitives\\nYear: 2022\\n\\nAbstract: In ToSC 2021(2), Sun et al. implemented an automatic search with the Boolean satisfiability problem (SAT) method on GIFT-128 and identified a 19-round linear approximation with the expected linear potential being 2(-117.43), which is utilised to launch a 24-round attack on the cipher. In this addendum, we discover a new 19-round linear approximation with a lower expected linear potential. However, in the attack, one more round can be appended after the distinguisher. As a result, we improve the previous optimal linear attack by one round and put forward a 25-round linear attack. Given that the optimal differential attack on GIFT-128, for now, covers 27-round, the resistances of the cipher against differential and linear attacks still have a 2-round gap.\",\n \"Title: Related-Tweak Impossible Differential Cryptanalysis of Reduced-Round TweAES\\nYear: 2021\\n\\nAbstract: We consider the related-tweak impossible differential cryptanalysis of TweAES. It is one of the underlying primitives of Authenticated Encryption with Associated Data (AEAD) scheme ESTATE which was accepted as one of second-round candidates in the NIST Lightweight Cryptography Standardization project. Firstly, we reveal several properties of TweAES, which show what kinds of distinguishers are more effective in recovering keys. With the help of automatic solver Simple Theorem Prover (STP), we achieve many 5.5-round related-tweak impossible differentials with fixed input differences and output differences that just have one active byte. Then, we implement 8-round key recovery attacks against TweAES based on one of these 5.5-round distinguishers. Moreover, another 5.5-round distinguisher that has four active bytes at the end is utilized to mount a 7-round key recovery attack against TweAES, which needs much lower attack complexities than the 6-round related-tweak impossible differential attack of TweAES in the design document. Our 8round key recovery attack is the best one against TweAES in terms of the number of rounds and complexities so far.\",\n \"Title: Improved Attacks on GIFT-64\\nYear: 2021\\n\\nAbstract: One of the well-known superiorities of GIFT-64 over PRESENT lies in the correction of the strong linear hull effect. However, apart from the investigation of the 9-round linear hull effect in the design document, we find no linear attack result on GIFT-64. Although we do not doubt the security of GIFT-64 regarding the linear cryptanalysis, the actual resistance of the cipher to the linear attack should be evaluated since it promotes a comprehensive perception of the soundness of GIFT-64. Motivated by this observation, we implement an automatic search and find a 12-round linear distinguisher whose dominating trail is an optimal linear characteristic. Following that, the first 19-round linear attack is launched by utilising the newly identified distinguisher. On the other side, we notice that the previous differential attack of GIFT-64 covering 20 rounds claims the entire codebook. To reduce the data complexity of the 20-round attack, we apply the automatic method to exhaustively check 13-round differential trails with probabilities no less than \\n \\n \\n \\n $$2^{-64}$$\\n \\n and identify multiple 13-round differentials facilitating 20-round attacks without using the full codebook. One of the candidate differentials with the maximum probability and the minimum number of guessed subkey bits is then employed to realise the first 20-round differential attack without relying on the complete codebook. Given the newly obtained results, we conjecture that the resistances of GIFT-64 against differential and linear attacks do not have a significant gap. Also, we note that the attack results in this paper are far from threatening the security of GIFT-64.\",\n \"Title: Revisiting the Extension of Matsui's Algorithm 1 to Linear Hulls: Application to TinyJAMBU\\nYear: 2022\\n\\nAbstract: At EUROCRYPT '93, Matsui introduced linear cryptanalysis. Both Matsui's Algorithm 1 and 2 use a linear approximation involving certain state bits. Algorithm 2 requires partial encryptions or decryptions to obtain these state bits after guessing extra key bits. For ciphers where only part of the state can be obtained, like some stream ciphers and authenticated encryption schemes, Algorithm 2 will not work efficiently since it is hard to implement partial encryptions or decryptions. In this case, Algorithm 1 is a good choice since it only involves these state bits, and one bit of key information can be recovered using a single linear approximation trail. However, when there are several strong trails containing the same state bits, known as the linear hull effect, recovering key bits with Algorithm 1 is infeasible. To overcome this, Rock and Nyberg extended Matsui's Algorithm 1 to linear hulls. However, Rock and Nyberg found that their theoretical estimates are quite pessimistic for low success probabilities and too optimistic for high success probabilities. To deal with this, we construct new statistical models where the theoretical success probabilities are in a good accordance with experimental ones, so that we provide the first accurate analysis of the extension of Matsui's Algorithm 1 to linear hulls. To illustrate the usefulness of our new models, we apply them to one of the ten finalists of the NIST the first cryptanalysis under the nonce-respecting setting on the full TinyJAMBU v1 and the round-reduced TinyJAMBU v2, where partial key bits are recovered. Our results do not violate the security claims made by the designers.\",\n \"Title: More Inputs Makes Difference: Implementations of Linear Layers Using Gates with More Than Two Inputs\\nYear: 2022\\n\\nAbstract: Lightweight cryptography ensures cryptography applications to devices with limited resources. Low-area implementations of linear layers usually play an essential role in lightweight cryptography. The previous works have provided plenty of methods to generate low-area implementations using 2-input xor gates for various linear layers. However, it is still challenging to search for smaller implementations using two or more inputs xor gates. This paper, inspired by Banik et al., proposes a novel approach to construct a quantity of lower area implementations with (n + 1)-input gates based on the given implementations with n-input gates. Based on the novel algorithm, we present the corresponding search algorithms for n = 2 and n = 3, which means that we can efficiently convert an implementation with 2-input xor gates and 3-input xor gates to lower-area implementations with 3-input xor gates and 4-input xor gates, respectively. We improve the previous implementations of linear layers for many block ciphers according to the area with these search algorithms. For example, we achieve a better implementation with 4-input xor gates for AES MixColumns, which only requires 243 GE in the STM 130 nm library, while the previous public result is 258.9 GE. Besides, we obtain better implementations for all 5500 lightweight matrices proposed by Li et al. at FSE 2019, and the area for them is decreased by about 21% on average.\",\n \"Title: A Greater GIFT: Strengthening GIFT Against Statistical Cryptanalysis\\nYear: 2022\\n\\nAbstract: GIFT-64 is a 64-bit block cipher with a 128-bit key that is more lightweight than PRESENT. This paper provides a detailed analysis of GIFT-64 against differential and linear attacks. Our work complements automatic search methods for the best differential and linear characteristics with a careful manual analysis. This hybrid approach leads to new insights. In the differential setting, we theoretically explain the existence of differential characteristics with two active S-boxes per round and derive some novel properties of these characteristics. Furthermore, we prove that all optimal differential characteristics of GIFT-64 covering more than seven rounds must activate two S-boxes per round. We can construct all optimal characteristics by hand. In parallel to the work in the differential setting, we conduct a similar analysis in the linear setting. However, unlike the clear view in differential setting, the optimal linear characteristics of GIFT-64 must have at least one round activating only one S-box. Moreover, with the assistance of automatic searching methods, we identify 24 GIFT-64 variants achieving better resistance against differential attack while maintaining a similar security level against a linear attack. Since the new variants strengthen GIFT-64 against statistical cryptanalysis, we claim that the number of rounds could be reduced from 28 to 26 for the variants. This observation enables us to create a cipher with lower energy consumption than GIFT-64. Similarly to the case in GIFT-64, we do not claim any related-key security for the round-reduced variant as this is not relevant for most applications.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":66,"string":"66"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13351,"string":"13,351"}}},{"rowIdx":13352,"cells":{"question_id":{"kind":"string","value":"Qianqian Zhang"},"question":{"kind":"string","value":"Generate an abstract for the title \"Machine Learning for Predictive On-Demand Deployment of UAVs for Wireless Communications.\" using the following items: 1. Machine learning framework\n2. Unmanned aerial vehicles (UAVs)\n3. Wireless service\n4. Gaussian mixture model (GMM)\n5. Power consumption"},"answer":{"kind":"string","value":"In this paper, a novel machine learning (ML) framework is proposed for enabling a predictive, efficient deployment of unmanned aerial vehicles (UAVs), acting as aerial base stations (BSs), to provide on-demand wireless service to cellular users. In order to have a comprehensive analysis of cellular traffic, an ML framework based on a Gaussian mixture model (GMM) and a weighted expectation maximization (WEM) algorithm is introduced to predict the potential network congestion. Then, the optimal deployment of UAVs is studied with the objective of minimizing the power needed for UAV transmission and mobility, given the predicted traffic. To this end, first, the optimal partition of service areas of each UAV is derived, based on a fairness principle. Next, the optimal location of each UAV that minimizes the total power consumption is derived. Simulation results show that the proposed ML approach can reduce power needed for downlink transmission and mobility by over 20% and 80%, respectively, compared with an optimal deployment of UAVs with no ML prediction."},"correct_answer":{"kind":"string","value":"In this paper, a novel machine learning (ML) framework is proposed for enabling a predictive, efficient deployment of unmanned aerial vehicles (UAVs), acting as aerial base stations (BSs), to provide on-demand wireless service to cellular users. In order to have a comprehensive analysis of cellular traffic, an ML framework based on a Gaussian mixture model (GMM) and a weighted expectation maximization (WEM) algorithm is introduced to predict the potential network congestion. Then, the optimal deployment of UAVs is studied with the objective of minimizing the power needed for UAV transmission and mobility, given the predicted traffic. To this end, first, the optimal partition of service areas of each UAV is derived, based on a fairness principle. Next, the optimal location of each UAV that minimizes the total power consumption is derived. Simulation results show that the proposed ML approach can reduce power needed for downlink transmission and mobility by over 20% and 80%, respectively, compared with an optimal deployment of UAVs with no ML prediction."},"documents":{"kind":"list like","value":["Title: A utility-based capacity optimization framework for achieving cooperative diversity in the hierarchical converged heterogeneous wireless networks\nYear: 2008\n\nAbstract: A hierarchical convergence mechanism for the heterogeneous wireless communication system via the heterogeneous cooperative relay node is presented in this paper, in which the techniques of cooperative communication and wireless relay are utilized to improve performances of the individual user and the overall converged networks. In order to evaluate the benefits of the proposal, a utility-based capacity optimization framework for achieving the heterogeneous cooperative diversity gain is proposed. The heterogeneous cooperative capacity, relay selection and power allocation theoretical models are derived individually. The joint optimization model for relay selection and power allocation is presented as well. Owing to the computation complexity, the sub-optimal cooperative relay selection algorithm, the sub-optimal power allocation algorithm and the sub-optimal joint algorithm are determined to approach the maximum overall networks' spectrum efficiency. These proposed algorithms are designed in conformance to guarantee the equivalent transmission rates of the different wireless access networks. The simulation results demonstrate that the utility-based capacity model is available for the heterogeneous cooperative wireless communication system, and the proposed algorithms can improve performances by achieving the cooperative gain and taking full advantage of the cross-layer design. Copyright © 2008 John Wiley & Sons, Ltd.","Title: Detecting for the aerial small target in infrared image based on the correlation coefficients of nonsubsampled contourlet transform.\nYear: 2012\n\nAbstract: In order to solve the practical problem of the infrared small target's detecting in the sky, a detecting algorithm based on NSCT (nonsubsampled contourlet transform) is proposed. Firstly, taking advantage of the excellent property of the transform, this algorithm analyses the different property of the NSCT coefficients of noise, background edge and signal, then computes the normalized correlation coefficients between scales for the transform coefficients. Subsequently, according to the adaptive method of threshold, the coefficients of background edge and noise are suppressed and then the image which includes the enhanced target is acquired by the inverse transform. In the end, taking the target area into account, the reconstructed image is segmented and the final detecting result is acquired by considering the position correlation of the target between frames. Experimental results show that the method given by this paper can detect small target accurately. Compared with some traditional method, it has certain advantage in background suppressing and can acquire high SNR (signal noise ratio) value. © 2012 IEEE.","Title: Management Motivation and Earnings Management Methods\nYear: 2013\n\nAbstract: In this paper, we study the effectiveness of the management motivations on earnings management methods based on thousands of samples between 2006 and 2011. The empirical results indicate that Real Earnings Management is used to manipulate the earnings in order to turn a profit, avoid loss, refinance, and change executives. The companies with higher executive compensations intend to use REM. However, making big profits by using Real Earnings Management activities is not popular because the capital market in China is not perfect enough.","Title: A verifiable secret sharing scheme without dealer in vector space\nYear: 2011\n\nAbstract: Based on the (+, +) homomorphism property of shamir's (t, n) secret sharing scheme, Harn and Lin proposed a (n, t, n) secret sharing scheme, in which each shareholder also acts as a dealer and the master secret was decided by the sub-secret of each shareholder. But this scheme is only suited to the threshold access structure. In this paper, we firstly define the (+, +) homomorphism property of secret sharing scheme in vector space. Then we extend the idea of (n, t, n) secret sharing scheme to vector space access structure, and define the secret sharing scheme without dealer in vector space and propose a verifiable secret sharing scheme without dealer in vector space based on the intractability of discrete logarithm. Compared with Harn and Lin's (n, t, n) secret sharing scheme, the proposed scheme is more general and is applied more widely since it is suited to vector space access structure.","Title: Synthesis and Characterization of Eco-friendly Composite: Poly(Ethylene Glycol)-Grafted Expanded Graphite/Polyaniline.\nYear: 2011\n\nAbstract: In this paper, synthesis and characterization of poly(ethylene glycol)grafted expanded graphite/polyaniline (PEG-grafted EG/PANi) as a novel eco-friendly composite material was reported. EG as substrate prepared from expandable graphite was firstly synthesized by in-situ polymerization at the presence of aniline (An) to obtain EG/PANi, and then graft polymerization with as-prepared PEG-grafted PANi (PEG-g-PANi) composite under no tough conditions. Structural characteristics of the products were evaluated by infrared spectrum (ER), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The experimental results have shown that the product of PEG-grafted EG/PANi composite were synthesized by facile method.","Title: The Implementation of XPDL Workflow Verification Service Based on SaaS\nYear: 2010\n\nAbstract: The process sub-model is the core of workflow model, verifying process sub-model before deployment can reduce the cost of shutdown, inspection and repair at run-time. This paper proposes verification algorithms, which focus on structural errors of process sub-model, and those algorithms will use the characteristics of the extended Petri net discussed in this paper. Simultaneously, this paper explains how to design a XPDL Validator based on SaaS and it emphasis on mapping XPDL process definition to extended Petri net.","Title: Cooperative Multi-Antenna Relaying In Heterogeneous Networks\nYear: 2009\n\nAbstract: In this paper, we investigate the performance of heterogeneous networks with multi-antenna cooperative relays. Specifically, threshold-based maximum ratio combining (MRC) and selection combining (SC) schemes are adopted for decoding at the relays and the end-to-end (EM) error rate performance is analyzed by assuming a Nakagami channel model. Numerical results show that the deployment of multi-antennas can reduce the number of required relay nodes, and thus significantly reduce the system cost. On the other hand, the selection of optimal decoding threshold depends on the number of relay nodes, number of antennas, as well as the average SNR value at the receiver. It is also demonstrated that when the BER requirement is not high, the SC relaying scheme is sufficient to provide satisfactory performance, such that the complexity of relays can be effectively reduced.","Title: Next-generation sequencing data processing: Analysis of unmapped reads and extremely high mapped peaks.\nYear: 2012\n\nAbstract: Next-generation sequencing (NGS) and its applications are widely used in studying gene regulation and epigenetic mechanisms due to its decreasing cost and high throughput. Here we used MNase-seq technology to determine the nucleosome positions in human erythroleukemia k562 cells by direct sequencing of nucleosome ends with the SOLiD high-throughput sequencing technique. However, during the reads mapping and data pre-analysis steps, only 40% of the sequenced reads can be mapped to the reference genome hg19 and there are some extremely high peaks (EHPs) in the profiles of mapped reads on the reference genome. Mathematical models were developed to analyze the unmapped reads and nearly 25.3% of the unmapped reads were found due to genome variants, base-calling errors and gaps of the reference genome. We also investigated EHPs and proposed methods to deal with the EHPs for the downstream data analysis. © 2012 IEEE.","Title: Consensus analysis for a class of stochastic PSO algorithm\nYear: 2014\n\nAbstract: Most of the existing results mainly concentrate on the convergence analysis and stability analysis of Particle Swarm Optimization (PSO) in the presence of @w@?[0, 1]. However, few existing works discuss the convergence and the stability of time-varying stochastic PSO swarm system from the perspective of the consensus. This paper firstly proposes an improved consensus protocol on the basis of the velocity and position equations of the canonical PSO algorithm, and transforms the dynamical PSO system into one new linear discrete-time system including random variables. Finally several important theorems concerning the mean square consensus are provided according to the existing important results of nonnegative random matrices, stability theory of large-scale system, etc. Furthermore, the boundary of consensus region is given to better select the parameters in PSO algorithm. Finally, numerical simulation results chiefly discuss the convergence analysis of each particle and demonstrate the effectiveness of the above-mentioned theorems.","Title: Internet addiction among Chinese adolescents: The effect of parental behavior and self-control.\nYear: 2014\n\nAbstract: •Adolescents with IA experience more unfavorable parental behavior than the non-IA.•Adolescents with IA have lower capacity of self-control than the non-IA.•Parental behavior and self-control both predict Internet addiction directly.•Self-control also acts as a mediator between parental behavior and Internet addiction.•The results are discussed from the view of Chinese Confucian filial piety.","Title: Time-Aware Collaborative Filtering for Recommender Systems.\nYear: 2012\n\nAbstract: Traditional collaborative filtering algorithms only take into account the users' historical ratings, which ignore the user-interest drifting and item-popularity changing over a long period of time. Aiming to the above problems, a time-aware collaborative filtering algorithm is proposed, which tracks user interests and item popularity over time. We extend the widely used neighborhood based algorithms by incorporating two kinds of temporal information and develop an improved algorithm for making timely recommendations. Experimental results show that the proposed approach can efficiently improve the accuracy of the prediction.","Title: The Multiple Population Co-evolution PSO Algorithm.\nYear: 2014\n\nAbstract: In order to overcome the standard particle swarm optimization algorithm which is easily trapped in local minima and optimize the shortcoming of low precision, this paper proposed a way which can make multiple information exchange between particles come true: the multiple population co-evolution PSO algorithm. This paper proposes a multiple population co-evolutionary algorithm to achieve communication among populations, and then show the feasibility and effectiveness of this algorithm through experiments.","Title: Energy-efficient resource allocation for OFDMA two-way relay networks with imperfect CSI\nYear: 2015\n\nAbstract: Most of the existed works on the radio resource allocation (RRA) problem commonly assume the channel-state information (CSI) can be perfectly obtained by the transmission source. However, such assumption is not practical in the realistic wireless systems. In this work, we consider the practical implementation issues of resource allocation in orthogonal frequency division multiple access (OFDMA) two-way relay networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, only the estimated channel status is known by the source. In this context, a joint optimization of subcarrier pairing and allocation, relay selection, and transmit power allocation is formulated in OFDMA two-way amplify-and-forward relay networks. Moreover, the objective of this work is to minimize the energy consumption of the overall system. Further, to ensure the quality of service (QoS) or data rate requirement, the energy consumption must be minimized without compromising the QoS. Therefore, by applying convex optimization techniques, energy-efficient algorithms are developed with the objective to minimize the total transmit power with guaranteeing the required data rates. Through simulation studies, energy consumption performance of the systems under the proposed schemes is investigated. It can be observed that our proposed scheme can improve the energy consumption performance of the considered system.","Title: A combinatorial double auction based resource allocation mechanism with multiple rounds for geo-distributed data centers\nYear: 2016\n\nAbstract: With the explosion of application of big data, it becomes inefficient and infeasible to process big data stream by using conventional data service infrastructure and management system. Cloud computing platform having multiple geo-distributed data centers is expected to be the most efficient platform to process the big data stream. In this paper, a multi-round combinational double auction based mechanism is proposed to allocate the resources of geo-distributed data centers to multiple users with large data stream processing tasks. This mechanism combines the advantages of combinatorial auction and double auction. In the proposed mechanism, the different types of VMs can be integrated into a bundle to be bid. The auction is double and conducted from both users and data centers. Different from existed double auctions, the QoS level is taken into consideration. In addition, the multiple rounds mode is adopted, so the failed users and data centers have the chance to adjust bids and asks to participate next auction round, increasing the ratio of successful transactions. Simulation results validate the effectiveness of the proposed mechanism.","Title: Quantum Game Theory for Beam Alignment in Millimeter Wave Device-to-Device Communications.\nYear: 2016\n\nAbstract: In this paper, the problem of optimized beam alignment for wearable device-to-device (D2D) communications over millimeter wave (mmW) frequencies is studied. In particular, a noncooperative game is formulated between wearable communication pairs that engage in D2D communications. In this game, wearable devices acting as transmitters autonomously select the directions of their beams so as to maximize the data rate to their receivers. To solve the game, an algorithm based on best response dynamics is proposed that allows the transmitters to reach a Nash equilibrium in a distributed manner. To further improve the performance of mmW D2D communications, a novel quantum game model is formulated to enable the wearable devices to exploit new quantum directions during their beam alignment so as to further enhance their data rate. Simulation results show that the proposed game-theoretic approach improves the performance, in terms of data rate, of about 7 5 % compared to a uniform beam alignment. The results also show that the quantum game model can further yield up to 2 0 % improvement in data rates, relative to the classical game approach.","Title: An Improved Method Of Compensating The Mutual Coupling Effect For Aperture Synthesis Radiometers\nYear: 2016\n\nAbstract: In aperture synthesis radiometers (ASRs), the mutual coupling effect between antennas is a key problem, which degrades the performance of ASRs and should be compensated. In this paper, an improved compensation method is proposed for ASRs, which is based on the receiving mutual impedance. The proposed method is verified by a one-dimension 5-channel L-band ASR. The experimental results show that the proposed method is superior over the existing method based on the transmitting mutual impedance, and is more appropriate to compensate the mutual coupling effect for ASRs.","Title: Energy Optimization by Flow Routing Algorithm in Data Center Network Satisfying Deadline Requirement.\nYear: 2016\n\nAbstract: Recently, the data center networks consume a large amount of energy, therefore, the energy saving is becoming increasingly important. Most previous works consolidate flows into as few switches as possible, which is not suitable for network-limited flows which require huge bandwidth to finish traffic transmission within deadline. To solve the challenge of energy-efficient path and deadline satisfied for network-limited flows, in this paper, we formulate the routing problem as a 0-1 integer programming problem, and propose a two-phase energy-efficient flow routing algorithm. Both energy saving and link utilization maximization are considered. Simulation results show that our algorithm achieves better performance in terms of energy saving, link utilization, as well as the active switch ratio.","Title: Dynamic Online Consumer Trust Forming Mechanism Research Based On Beijing, China\nYear: 2016\n\nAbstract: This research identifies a number of key factors related to online consumer trust and establishes a model based on the System Dynamic method to find out the relationships between these factors and trust. This paper provides several contributions. Firstly it reviews the previous works of online trust and identifies the major online trust building factors which mainly consists of business factors, consumer factors, commodities factors, and e-commerce environment factors. Secondly, it builds an online consumer trust forming mechanism model based on the analysis of literature reviews. Thirdly, the causal relationship between the forming factors and consumer trust was analyzed by the simulation of system dynamic method.","Title: Cooperative Receiver For Ambient Backscatter Communications With Multiple Antennas\nYear: 2017\n\nAbstract: In ambient backscatter communications (AmBC), a backscatter device can harvest power from ambient RF signals and modulate its information symbols over the ambient carriers without using complex RF transmitter. Conventional receiver design for AmBC focuses on tackling the direct link interference from the RF source. In this paper, a novel receiver, which is called cooperative receiver, is proposed to recover signals not only from the ambient backscatter device (A-BD), but also from the RF source. We first study the optimal maximum-likelihood (ML) detection for such system. Then, by exploiting the structural property of the system model, linear detectors and successive interference cancellation (SIC) based detectors are proposed. We also derive the closed-form bit error rate (BER) expressions for both ML detection and the proposed SIC algorithms. Finally, extensive numerical results show that the existence of backscattered signal in the considered system can significantly enhance the ML detection performance of the source signal, and the proposed SIC-based detectors can achieve near-ML detection performance for typical application scenarios.","Title: A Large Scale Data Transmission Control Mechanism across Data Centers\nYear: 2017\n\nAbstract: With the rapid development of the information technology, the scale of data is quickly increasing, and the more and more data centers are built by research institutions or commercial organizations. In order to collect and analyze the data, the end-to-end transmission for the large scale of data across data centers need be implemented. However, the existing works are mainly based on TCP or UDP, and can not meet the actual demand. For TCP, the transmission efficiency is low due to the frequent three-way handshake and the mismatch between the sending window and the link capacity. For UDP, the transmission is unreliable and the compatibility of the improved methods is poor. In order to solve the above problems, an end-to-end transmission control model based on session management is proposed. In this model, two kinds of agents and the session management mechanism are adopted to localize TCP three-way handshake in the data center and improve the transmission efficiency of the large scale data across data centers, and the improved UDP is used to the long-distance transmission between the agents in order to enhance the reliability of the end-to-end transmission. The experimental results show that the transmission control mechanism presented in this paper can effectively reduce the transmission delay and improve the efficiency of transmission for the large scale data.","Title: Cooperative Ambient Backscatter Communications for Green Internet-of-Things.\nYear: 2018\n\nAbstract: Ambient backscatter communication (AmBC) enables a passive backscatter device to transmit information to a reader using ambient RF signals, and has emerged as a promising solution to green Internet-of-Things (IoT). Conventional AmBC receivers are interested in recovering the information from the ambient backscatter device (A-BD) only. In this paper, we propose a cooperative AmBC (CABC) system in w...","Title: A Dual-Tree Complex Wavelet Transform Based Convolutional Neural Network for Human Thyroid Medical Image Segmentation\nYear: 2018\n\nAbstract: This research proposes a novel dual-tree complex wavelet transform based Convolutional Neural Network (WCNN) to perform organ tissue segmentation from medical images. Accurate and efficient segmentation on the medical image of human organ is a critical step towards disease diagnosis. For medical image segmentation tasks, conventional Convolutional Neural Networks (CNNs) are: 1) inclined to ignore crucial texture information of the image due to the limitations of typical pooling approaches, and 2) insufficiently robust to noise. To overcome the obstacles, a spectral domain transformation technique is adopted in the CNN. Specifically, a dual-tree complex wavelet pooling layer is concatenated to the traditional pooling process in a CNN. By using wavelet decomposition, the image becomes scalable in the spatial direction, allowing accurate recognition of textures. The WCNN decomposes the image into a number of wavelet subbands, and reduces noisy data by filtering out high-frequency subbands. The performance of WCNN is tested on standard image classification datasets, and applied for human thyroid optical coherence tomography (OCT) image segmentation. Compared to the traditional CNNs using max pooling, experimental results demonstrate that the WCNN approach obtains outstanding consistency and accuracy in the image segmentation domain.","Title: Medical Image Synthesis with Generative Adversarial Networks for Tissue Recognition\nYear: 2018\n\nAbstract: This paper presents an adversarial learning-based approach to synthesize medical images for medical image tissue recognition. The performance of medical image recognition models highly depends on the representativeness and sufficiency of training samples. The high expense of collecting large amounts of practical medical images leads to a demand of synthesizing image samples. In this research, generative adversarial networks (GANs), which consist of a generative network and a discriminative network, are applied to develop a medical image synthesis model. Specifically, deep convolutional GANs (DCGANs), Wasserstein GANs (WGANs), and boundary equilibrium GANs (BEGANs) are implemented and compared to synthesize medical images in this research. Convolutional neural networks (CNNs) are applied in the GAN models, which can capture feature representations that describe a high level of image semantic information. Then synthetic images are generated by employing the generative network mapping from random noise. The effectiveness of the generative network is validated by a discriminative network, which is trained to detect the synthetic images from real images. Through a minimax two-player game, the generative and discriminative networks can train each other. The generated synthetic images are used to train a CNN classification model for tissue recognition. Through the experiments with the synthetic images, the tissue recognition accuracy achieves 98.83%, which reveals the effectiveness and applicability of synthesizing medical images through the GAN models.","Title: Label-Assisted Transmission for Short Packet Communications: A Machine Learning Approach.\nYear: 2018\n\nAbstract: Short packet communications (SPC) will play an important role in future Internet-of-Things networks. Conventional pilot-assisted transmission (PAT) needs significant overhead to obtain accurate channel state information (CSI) for further symbol detection and bit recovery, thereby reducing the spectral efficiency of the transmission. In this paper, a machine learning framework called Label-Assisted...","Title: Parallel distributed computing based wireless sensor network anomaly data detection in IoT framework.\nYear: 2018\n\nAbstract: To reduce the energy consumption of wireless sensor networks (WSNs) and prolong the network lifetime, non-uniform clustering routing (DUCF) of WSNs based on distributed fuzzy logic interference is proposed. DUCF protocol fully considers the residual energy of node, the node degree and distance from the base station. Fuzzy rule is formulated based on experience and the probability of node being elected as cluster head and the size of cluster are obtained through fuzzy interference system. DUCF protocol forms non-uniform cluster and further balances the energy consumption among cluster heads. Simulation result indicates that the performances of DUCF protocol in network lifetime and energy consumption are superior to that of LEACH, CHEF and EAUCF protocol.","Title: Predictive Deployment of UAV Base Stations in Wireless Networks: Machine Learning Meets Contract Theory\nYear: 2018\n\nAbstract: In this paper, a novel framework is proposed to enable a predictive deployment of unmanned aerial vehicles (UAVs) as temporary base stations (BSs) to complement ground cellular systems in face of downlink traffic overload. First, a novel learning approach, based on the weighted expectation maximization (WEM) algorithm, is proposed to estimate the user distribution and the downlink traffic demand. Next, to guarantee a truthful information exchange between the BS and UAVs, using the framework of contract theory, an offload contract is developed, and the sufficient and necessary conditions for having a feasible contract are analytically derived. Subsequently, an optimization problem is formulated to deploy an optimal UAV onto the hotspot area in a way that the utility of the overloaded BS is maximized. Simulation results show that the proposed WEM approach yields a prediction error of around 10%. Compared with the expectation maximization and k-mean approaches, the WEM method shows a significant advantage on the prediction accuracy, as the traffic load in the cellular system becomes spatially uneven. Furthermore, compared with two event-driven deployment schemes based on the closest-distance and maximal-energy metrics, the proposed predictive approach enables UAV operators to provide efficient communication service for hotspot users in terms of the downlink capacity, energy consumption and service delay. Simulation results also show that the proposed method significantly improves the revenues of both the BS and UAV networks, compared with two baseline schemes.","Title: Constellation Learning-Based Signal Detection for Ambient Backscatter Communication Systems\nYear: 2019\n\nAbstract: Ambient backscatter communication (AmBC) is a promising solution to energy-efficient and spectrum-efficient Internet of Things with stringent power and cost constraints. In an AmBC system, recovering the tag information at the reader, however, is a challenging task due to the difficulty in acquiring the relevant channel-state information (CSI). To eliminate the need to estimate the CSI, in this paper, we propose a label-assisted transmission framework, in which two known labels are transmitted from the tag before data transmission. By exploring the received signal constellation information, we propose modulation-constrained expectation maximization algorithm, based on which two detection methods are developed. One method, referred to as constellation learning with labeled signals, learns the parameters by clustering the labeled signals and recovers the unlabeled signals by the learnt parameters. The other method, referred to as constellation learning with labeled and unlabeled signals, uses all received signals in clustering. Efficient initialization techniques are provided for the two clustering algorithms. Finally, extensive simulation results show that the proposed constellation learning methods achieve comparable performance as the optimal detector with perfect CSI.","Title: Exploiting Multiple Antennas for Cognitive Ambient Backscatter Communication\nYear: 2019\n\nAbstract: Cognitive ambient backscatter communication is a novel spectrum sharing paradigm, in which the backscatter system shares not only the same spectrum, but also the same radio-frequency source with the legacy system. Conventional energy detector (ED) suffers from severe error floor problem due to the existence of co-channel direct link interference (DLI) from the legacy system. In this paper, novel error-floor-free detectors are proposed to tackle the DLI using multiple receive antennas at the reader. First, beamforming-assisted ED and likelihood-ratio-based detector are proposed for backscatter symbol detection when the reader has perfect channel state information (CSI). Then a novel statistical clustering framework is proposed for joint CSI feature learning and backscatter symbol detection. Extensive simulation results have shown that the proposed methods can significantly outperform the conventional ED. In addition, the proposed clustering-based methods perform comparably as their counterparts with perfect CSI.","Title: Multi-Antenna Beamforming Receiver for Cognitive Ambient Backscatter Communications.\nYear: 2018\n\nAbstract: Cognitive ambient backscatter communication (Am-BC) is a novel spectrum sharing paradigm for green Internet of Things, in which the backscatter system shares not only the same spectrum, but also the same radio frequency (RF) source with the legacy system. The conventional energy detector (ED) suffers from a severe error floor problem due to the existence of co-channel direct link interference (DLI) from the legacy system. In this paper, novel error-floor-free detectors are proposed to tackle the DLI through multi-antenna receive beamforming. A novel statistical clustering framework is proposed for joint channel state information (CSI) learning and backscatter symbol detection. Extensive simulation results have shown that the proposed methods can significantly outperform the conventional ED, and verified that the proposed clustering-based method achieves performance comparable to that of the perfect CSI cases.","Title: Clustering-Inspired Signal Detection for Ambient Backscatter Communication Systems.\nYear: 2018\n\nAbstract: In ambient backscatter communication (AmBC), it is a challenging task to recover the tag information at the reader due to the difficulty in obtaining the relevant channel state information (CSI). In this paper, we translate the signal detection problem into a clustering problem, for which two known labels are transmitted from the tag as the prior knowledge to assist clustering initialization and signal detection. By exploiting the received signals directly, two clustering-inspired detection methods are proposed, one is called clustering with labeled signals (CLS), and the other is referred to as clustering with labeled and unlabeled signals (CLUS). Both methods are developed based on the proposed modulation-constrained (MC) Gaussian mixture model (GMM). Finally, extensive simulation results show that the proposed methods only have small gaps compared with the optimal detection with perfect CSI.","Title: Network Formation Game for Multi-Hop Wearable Communications over Millimeter Wave Frequencies.\nYear: 2017\n\nAbstract: In this paper, the use of multi-hop, device-to-device communications over millimeter wave (mmW) frequencies is studied for effective wearable communications. In particular, the problem of uplink communications is studied for a wearable network in which each wearable device seeks to form a multi-hop path over mmW to access a cellular base station, in order to overcome the high channel loss caused by mmW attenuation and blockage. To analyze the optimal selection of the uplink path, a network formation game is formulated between all wearable devices. In this game, each wearable device autonomously chooses the uplink path that maximizes its utility function that captures the tradeoff between rate, delay, and privacy. To solve this game, a novel algorithm that combines best response dynamics with mixed-strategy techniques is proposed to find the mixed Nash network, which corresponds to a stable uplink structure at which no wearable device can improve its utility by changing its network formation decision. Simulation results show that the proposed game approach improves the average utility per wearable device of over 14% and 78%, respectively, compared with the direct transmission and the nearest next-hop schemes.","Title: A Clustering Detector for Spatial Modulation System\nYear: 2018\n\nAbstract: Spatial modulation (SM) is regarded as a promising multiple-input multiple-output (MIMO) technique since it exploits the additional spatial domain for transmitting information. For transceiver design in SM, the traditional schemes first estimate the channel state information (CSI) based on pilots for further decoding, which introduce significant overhead, thereby reducing the spectral efficiency of the transmission. In this paper, to avoid the channel estimation, we convert the signal detection problem into a cluster problem for SM system. Utilizing the inter-structure of the SM system, we propose a structured Gaussian mixture model (SGMM) with a reduced number of parameters to model the received signals. We also develop an SGMM-based expectation maximization algorithm (SGMM-EM) to cluster the received signals. The complexity of SGMM-EM algorithm is reduced significantly compared with traditional clustering algorithm. After clustering all the received signals, a label mapping method is developed to map each transmitted symbol to one of the clusters. Simulation results show that, with only a small number of iterations, the performance of our proposed scheme approaches to that of the optimal receiver with perfect CSI.","Title: Detection of Type, Blended Ratio, and Mixed Ratio of Pu'er Tea by Using Electronic Nose and Visible/Near Infrared Spectrometer.\nYear: 2019\n\nAbstract: The objective of this study was to find an intelligent and fast method to detect the type, blended ratio, and mixed ratio of ancient Pu'er tea, which is significant in maintaining order in the Pu'er tea industry. An electronic nose (E-nose) and a visible near infrared spectrometer (VIS/NIR spectrometer) were applied for tea sampling. Feature extraction was conducted using both the traditional method and a convolutional neural network (CNN) technique. Linear discriminant analysis (LDA) and partial least square regression (PLSR) were applied for pattern recognition. After sampling while using the traditional method, the analysis of variance (ANOVA) results showed that the mean differential value of each sensor should be selected as the optimal feature extraction method for E-nose data, and raw data comparison results showed that 19 peak/valley values and two slope values were extracted. While the format of E-nose data was in accord with the input format for CNN, the VIS/NIR spectrometer data required matrixing to meet the format requirements. The LDA and PLSR analysis results showed that CNN has superior detection ability, being able to acquire more local features than the traditional method, but it has the risk of mixing in redundant information, which can act to reduce the detection ability. Multi-source information fusion (E-nose and VIS/NIR spectrometer fusion) can collect more features from different angles to improve the detection ability, but it also contains the risk of adding redundant information, which reduces the detection ability. For practical detection, the type of Pu'er tea should be recognizable using a VIS/NIR spectrometer and the traditional feature extraction method. The blended ratio of Pu'er tea should also be identifiable by using a VIS/NIR spectrometer with traditional feature extraction. Multi-source information fusion with traditional feature extraction should be used if the accuracy requirement is extremely high; otherwise, a VIS/NIR spectrometer with traditional feature extraction is preferred.","Title: Resource Allocation for Symbiotic Radio System With Fading Channels.\nYear: 2019\n\nAbstract: In this paper, we investigate the resource allocation problem for the symbiotic radio system, in which the passive backscatter transmission is parasitic in the primary transmission, and the cooperative receiver simultaneously detects the signals transmitted from the active primary transmitter (PT) and the backscatter device (BD). In particular, channel fading is considered, and the ergodic weighted sum rate of the primary and backscatter transmissions is maximized by jointly optimizing the transmit power at the PT and the reflection coefficient at the BD under either long-term or short-term transmit-power constraint over the fading states. Two practical transmission setups are considered, where the relationship between the primary and backscatter transmissions is either commensal or parasitic. For the commensal setup, we fix the reflection coefficient as the maximum value and derive the optimal power allocation scheme based on the standard convex optimization procedure. For the parasitic setup, the weighted sum-rate maximization problem is non-convex, and we resort to the concave-convex procedure to derive a suboptimal solution. Simulation results demonstrate that in the commensal setup, the BD may realize transmission while causing no harmful interference to the primary system; in the parasitic setup, a higher backscatter data rate can be achieved through slightly sacrificing the primary transmission rate.","Title: Backscatter-NOMA: A Symbiotic System of Cellular and Internet-of-Things Networks.\nYear: 2019\n\nAbstract: Non-orthogonal multiple access (NOMA) is envisioned as a key technology to enhance the spectrum efficiency for 5G cellular networks. Meanwhile, ambient backscatter communication is a promising solution to the Internet of Things (IoT), due to its high spectrum efficiency and power efficiency. In this paper, we are interested in a symbiotic system of cellular and IoT networks and propose a backscatter-NOMA system, which incorporates a downlink NOMA system with a backscatter device (BD). In the proposed system, the base station (BS) transmits information to two cellular users according to the NOMA protocol, while a BD transmits its information over the BS signals to one cellular user using the passive radio technology. In particular, if the BS only serves the cellular user that decodes BD information, the backscatter-NOMA system turns into a symbiotic radio (SR) system. We derive the expressions of the outage probabilities and the ergodic rates and analyze the corresponding diversity orders and slopes for both backscatter-NOMA and SR systems. Finally, we provide the numerical results to verify the theoretical analysis and demonstrate the interrelationship between the cellular networks and the IoT networks.","Title: A Latent-Dirichlet-Allocation Based Extension For Domain Ontology Of Enterprise'S Technological Innovation\nYear: 2019\n\nAbstract: This paper proposed a method for building enterprise's technological innovation domain ontology automatically from plain text corpus based on Latent Dirichlet Allocation (LDA). The proposed method consisted of four modules: 1) introducing the seed ontology for domain of enterprise's technological innovation, 2) using Natural Language Processing (NLP) technique to preprocess the collected textual data, 3) mining domain specific terms from document collections based on LDA, 4) obtaining the relationship between the terms through the defined relevant rules. The experiments have been carried out to demonstrate the effectiveness of this method and the results indicated that many terms in domain of enterprise's technological innovation and the semantic relations between terms are discovered. The proposed method is a process of continuously cycles and iterations, that is the obtained objective ontology can be re-iterated as initial seed ontology. The constant knowledge acquisition in the domain of enterprise's technological innovation to update and perfect the initial seed ontology.","Title: An Open Source Modeling Framework for Interdependent Energy-Transportation-Communication Infrastructure in Smart and Connected Communities\nYear: 2019\n\nAbstract: Infrastructure in future smart and connected communities is envisioned as an aggregate of public services, including energy, transportation, and communication systems, all intertwined with each other. The intrinsic interdependency among these systems may exert the underlying influence on both design and operation of the heterogeneous infrastructures. However, few prior studies have tapped into the interdependency among these systems in order to quantify their potential impacts during standard operation. In response to this, this paper proposes an open-source, flexible, integrated modeling framework suitable for designing coupled energy, transportation, and communication systems and for assessing the impact of their interdependencies. First, a novel multi-level, multi-layer, multi-agent approach is proposed to enable flexible modeling of the interconnected systems. Then, for the framework's proof of concept, preliminary component and system-level models for different systems are designed and implemented using Modelica, an equation-based object-oriented modeling language. Finally, three case studies of gradually increasing complexity are presented (energy, energy + transportation, and energy + transportation + communication) to evaluate the interdependencies among the three systems. Quantitative analyses show that the deviation of the average velocity on the road can be 10.5% and the deviation of the power drawn from the grid can be 7% with or without considering the transportation and communication system at the peak commute time, indicating the presence of notable interdependencies. The proposed modeling framework also has the potential to be further extended for various modeling purposes and use cases, such as dynamic modeling and optimization, resilience analysis, and integrated decision making in future connected communities.","Title: Cooperative Ambient Backscatter System: A Symbiotic Radio Paradigm for Passive IoT\nYear: 2019\n\nAbstract: Cooperative ambient backscatter system is a novel symbiotic radio paradigm, in which the passive backscatter transmission shares not only the same spectrum but also the same radio-frequency source with the active primary transmission. By considering the unique features of the ambient backscatter system, three practical symbiotic transmission schemes are proposed, in which the relationships between the primary and backscatter transmissions are commensal, parasitic, and competitive, respectively. The achievable rates for both primary and backscatter transmissions are derived for particular fading state. Then, optimal power allocation is obtained for each transmission scheme under the average power constraint. Simulation results are provided to corroborate theoretical studies.","Title: A review of improved extreme learning machine methods for data stream classification\nYear: 2019\n\nAbstract: Classification is a hotspot in data stream mining and has gained increasing interest from various research fields. Compared with traditional data stream classification methods, Extreme Learning Machine (ELM) has attracted much attention because of its efficiency and simplicity, which inspired the development of many improved ELM algorithms that have been proposed in the past few years. This paper mainly reviews the current state of ELM used to classify data streams and its variants. First, we introduce the principles of ELM and the existing problems of data stream classification. Then we provide an overview of various improvements made to ELM, which further improves its stability, accuracy and generalization ability and present the practical applications of ELM used in data stream classification. Finally, the paper highlights the existing problems of ELM used for data stream mining and development prospects of ELM in the future.","Title: Intelligent User Association for Symbiotic Radio Networks using Deep Reinforcement Learning.\nYear: 2019\n\nAbstract: In this paper, we are interested in \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">symbiotic radio networks</italic>\n (SRNs), in which an \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Internet-of-Things</italic>\n (IoT) network parasitizes in a primary cellular network to achieve spectrum-, energy-, and infrastructure-efficient communications. Each IoT device transmits its own information by backscattering the signals from the primary network without using active \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">radio-frequency</italic>\n (RF) transmitter chain. We consider the symbiosis between the cellular network and the IoT network and focus on the user association problem in SRN. Specifically, the \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">base station</italic>\n (BS) in the primary network serves multiple cellular users using \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">time division multiple access</italic>\n (TDMA) and each IoT device is associated with one cellular user for information transmission. The objective of user association is to link each IoT device to an appropriate cellular user by maximizing the sum rate of all IoT devices. However, the difficulty in obtaining the full real-time channel information makes it difficult to design an optimal policy for this problem. To overcome this issue, we propose two \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">deep reinforcement learning</italic>\n (DRL) algorithms, both use historical information to infer the current information in order to make appropriate decisions. One algorithm, referred to as centralized DRL, makes decisions for all IoT devices at one time with globally available information. The other algorithm, referred to as distributed DRL, makes a decision only for one IoT device at one time using locally available information. Finally, simulation results show that the two proposed DRL algorithms achieve performance comparable to the optimal user association policy which requires perfect real-time information, and the distributed DRL algorithm has the advantage of scalability.","Title: Distributed Generative Adversarial Networks for mmWave Channel Modeling in Wireless UAV Networks\nYear: 2021\n\nAbstract: In this paper, a novel framework is proposed to enable air-to-ground channel modeling over millimeter wave (mmWave) frequencies in an unmanned aerial vehicle (UAV) wireless network. First, an effective channel estimation approach is developed to collect mmWave channel information allowing each UAV to train a local channel model via a generative adversarial network (GAN). Next, in order to share the channel information between UAVs in a privacy-preserving manner, a cooperative framework, based on a distributed GAN architecture, is developed to enable each UAV to learn the mmWave channel distribution from the entire dataset in a fully distributed approach. The necessary and sufficient conditions for the optimal network structure that maximizes the learning rate for information sharing in the distributed network are derived. Simulation results show that the learning rate of the proposed GAN approach will increase by sharing more generated channel samples at each learning iteration, but decrease given more UAVs in the network. The results also show that the proposed GAN method yields a higher learning accuracy, compared with a standalone GAN, and improves the average rate for UAV downlink communications by over 10%, compared with a baseline real-time channel estimation scheme.","Title: Semi-Supervised Learning for Channel Charting-Aided IoT Localization in Millimeter Wave Networks\nYear: 2021\n\nAbstract: In this paper, a novel framework is proposed for channel charting (CC)-aided localization in millimeter wave networks. In particular, a convolutional autoencoder model is proposed to estimate the three-dimensional location of wireless user equipment (UE), based on multipath channel state information (CSI), received by different base stations. In order to learn the radio-geometry map and capture the relative position of each UE, an autoencoder-based channel chart is constructed in an unsupervised manner, such that neighboring UEs in the physical space will remain close in the channel chart. Next, the channel charting model is extended to a semi-supervised framework, where the autoencoder is divided into two components: an encoder and a decoder, and each component is optimized individually, using the labeled CSI dataset with associated location information, to further improve positioning accuracy. Simulation results show that the proposed CC-aided semi-supervised localization yields a higher accuracy, compared with existing supervised positioning and conventional unsupervised CC approaches.","Title: Gaussian process regression-based learning rate optimization in convolutional neural networks for medical images classification\nYear: 2021\n\nAbstract: •Propose two novel learning rate optimization algorithms for a popular optimizer.•Apply the Gaussian Process Regression method to predict the classification accuracy.•Obtain a robust learning rate updating rule during the classification process.•Study new medical images that map the lipids and proteins without destroying tissue.•Demonstrate the superiority of the proposed algorithms for classification.","Title: Discovering Properties about Arrays via Path Dependence Analysis\nYear: 2021\n\nAbstract: Array, as a fundamental data structure, is widely used in programs. Automated reasoning about arrays needs to discover properties about ranges of elements at certain program points. Such properties are formally specified by universally quantified formulas. A universally quantified formula usually includes two parts: the index range and the properties of the corresponding array elements. In this pa...","Title: Detecting Abnormal Social Network Accounts With Hurst Of Interest Distribution\nYear: 2021\n\nAbstract: With the rapid development of the Internet since the beginning of the 21st century, social networks have provided a significant amount of convenience for work, study, and entertainment. Specifically, because of the irreplaceable superiority of social platforms in disseminating information, criminals have thus updated the main methods of social engineering attacks. Detecting abnormal accounts on social networks in a timely manner can effectively prevent the occurrence of malicious Internet events. Different from previous research work, in this work, a method of anomaly detection called Hurst of Interest Distribution is proposed based on the stability of user interest quantifiable from the content of users' tweets, so as to detect abnormal accounts. In detail, the Latent Dirichlet Allocation model is adopted to classify blog content on Twitter into topics to calculate and obtain the topic distribution of tweets sent by a single user within a period of time. Then, the stability degree of the user's tweet topic preference is calculated according to the Hurst index to determine whether the account is compromised. Through experiments, the Hurst indexes of normal and abnormal accounts are found to be significantly different, and the detection rate of abnormal accounts using the proposed method can reach up to 97.93%.","Title: Novel stability conditions of linear time-varying impulsive positive systems based on indefinite Lyapunov functions *\nYear: 2021\n\nAbstract: This paper investigates the global asymptotic stability of linear time-varying impulsive positive systems (IPSs). Several novel stability criteria of linear time-varying IPSs with different types of impulsive effects are proposed by constructing an indefinite time-varying copositive Lyapunov function. In particular, by using the maximum and average dwell time methods, we discuss the stability of t...","Title: On moment exponential stability of Markovian switching integral delay systems\nYear: 2021\n\nAbstract: This paper studies the moment exponential stability analysis of a class of Markovian switching integral delay systems (MSIDSs). The existence, uniqueness and stability of the solution are discussed firstly. Secondly, by selecting appropriate Lyapunov-Krasovskii (L-K) functionals, delay-dependent sufficient conditions are given such that the general form of MSIDSs and the special form of MSIDSs having multiple delays are mean square exponentially stable respectively. The results are then generalized to robust stability of MSIDSs having multiple delays with uncertain parameters. Finally, numerical examples are given to illustrate the effectiveness of the proposed theoretical results.","Title: Experimental Investigation and Fault Diagnosis for Buckled Wet Clutch Based on Multi-Speed Hilbert Spectrum Entropy\nYear: 2021\n\nAbstract: The multi-disc wet clutch is widely used in transmission systems as it transfers the torque and power between the gearbox and the driving engine. During service, the buckling of the friction components in the wet clutch is inevitable, which can shorten the lifetime of the wet clutch and decrease the vehicle performance. Therefore, fault diagnosis and online monitoring are required to identify the buckling state of the friction components. However, unlike in other rotating machinery, the time-domain features of the vibration signal lack efficiency in fault diagnosis for the wet clutch. This paper aims to present a new fault diagnosis method based on multi-speed Hilbert spectrum entropy to classify the buckling state of the wet clutch. Firstly, the wet clutch is classified depending on the buckling degree of the disks, and then a bench test is conducted to obtain vibration signals of each class at varying speeds. By comparing the accuracy of different classifiers with and without entropy, Hilbert spectrum entropy shows higher efficiency than time-domain features for the wet clutch diagnosis. Thus, the classification results based on multi-speed entropy achieve even better accuracy.","Title: KGAT-SR: Knowledge-Enhanced Graph Attention Network for Session-based Recommendation\nYear: 2021\n\nAbstract: As a main task of session-based recommendation, next interaction (item) recommendation aims to recommend the next possible interaction (e.g., click on a song) given a session context (i.e., a list of happened interactions). This task faces the challenge of how to generate accurate recommendations when only the intra-session dependencies are available. Existing recommendation models usually fail to exploit the knowledge about items to model intra-session dependencies. Therefore, this paper addresses the problem of next item recommendation given a session context of an ordered, single-type-action, and anonymous session, and investigates how to effectively model intra-session dependencies by leveraging the knowledge from a knowledge graph (KG). We propose a novel model called Knowledge-enhanced Graph Attention Network for Session-based Recommendation (KGAT-SR). Its core idea is that the knowledge about items from a KG is exploited via knowledge graph attention network to generate a knowledge enhanced session graph (KESG). After the KESG is aggregated via weighted graph attention, the node features and graph topology in the graph are utilized to generate accurate session embedding, which can be used to recommend the next item. Experiments show that KGAT-SR significantly outperforms the state-of-the-art models for next item recommendation. KGAT-SR's source code is available at https://github.com/hudske/KGAT-SR.","Title: Leaving No One Behind: A Multi-Scenario Multi-Task Meta Learning Approach for Advertiser Modeling\nYear: 2022\n\nAbstract: ABSTRACTAdvertisers play an essential role in many e-commerce platforms like Taobao and Amazon. Fulfilling their marketing needs and supporting their business growth is critical to the long-term prosperity of platform economies. However, compared with extensive studies on user modeling such as click-through rate predictions, much less attention has been drawn to advertisers, especially in terms of understanding their diverse demands and performance. Different from user modeling, advertiser modeling generally involves many kinds of tasks (e.g. predictions of advertisers' expenditure, active-rate, or total impressions of promoted products). In addition, major e-commerce platforms often provide multiple marketing scenarios (e.g. Sponsored Search, Display Ads, Live Streaming Ads) while advertisers' behavior tend to be dispersed among many of them. This raises the necessity of multi-task and multi-scenario consideration in comprehensive advertiser modeling, which faces the following challenges: First, one model per scenario or per task simply doesn't scale; Second, it is particularly hard to model new or minor scenarios with limited data samples; Third, inter-scenario correlations are complicated, and may vary given different tasks. To tackle these challenges, we propose a multi-scenario multi-task meta learning approach (M2M) which simultaneously predicts multiple tasks in multiple advertising scenarios. Specifically, we introduce a novel meta unit that incorporates rich scenario knowledge to learn explicit inter-scenario correlations and can easily scale to new scenarios. Furthermore, we present a meta attention module to capture diverse inter-scenario correlations given different tasks, and a meta tower module to enhance the capability of capturing the representation of scenario-specific features. Compelling results from both offline evaluation and online A/B tests demonstrate the superiority of M2M over state-of-the-art methods.","Title: Analysis of the effect of objective function on the performance of the algorithm for the inverse kinematic of manipulator\nYear: 2021\n\nAbstract: In order to analyze the influence of the objective function on the algorithm, we compare the common definitions of objective functions and propose a piecewise objective function definition method based on error value to further improve the algorithm performance. Using classical swarm intelligence optimization algorithms such as DE, MABC, PSO, three types of objective functions are contrast analyze...","Title: A Big Data-Driven Approach to Analyze the Influencing Factors of Enterprise's Technological Innovation\nYear: 2022\n\nAbstract: A data-driven intelligent analysis method is proposed in this paper to explore and identify the enterprise's technological innovation influencing factors. Questionnaire surveys or expert interviews are usually adopted by the traditional evaluation methods for indicators of technological innovation selection. However, it inevitably involves human factors and experts' subjective judgments, which may affect the result of enterprises evaluation. The research presents an improved text clustering method based on a semantic concept model to explore and analyze the key influencing factors of enterprise's technological innovation. The study collects textual data from 400 enterprises in Beijing and smart analyzes the critical influencing factors of enterprise's technological innovation by using the proposed method. The influencing factors can be divided into seven categories. In addition, compared with the traditional K-means clustering method, the proposed method has a good effect. We proposed a methodology to conduct an intelligent analysis for enterprise's technological innovation under the data-driven. It can provide more objective and auxiliary suggestions for the evaluation of the enterprise's technology innovation.","Title: Mutualistic Mechanism in Symbiotic Radios\nYear: 2021\n\nAbstract: In symbiotic radio (SR), also called cognitive backscatter communications, a secondary transmitter (STx) transmits messages by modulating its information over the RF signals from a primary transmitter (PTx), and in return, the secondary transmission provides multipath gain instead of interference to the primary transmission when the spreading factor K of SR is large enough. In this paper, we are interested in the fundamental mutualistic mechanism between the primary and secondary transmissions in SR, which describes the condition through which the two systems can benefit each other. We first derive the closed-form expressions for the bit error rates (BERs) for both primary and secondary transmissions for general K, then obtain the condition on K to enable mutualistic symbiosis in SR. It is observed that the critical point of K is related to the average strengths of the direct and backscatter links when the number of receiving antennas is large. Extensive simulation and numerical results are provided to verify the accuracy of theoretical analysis and demonstrate the interrelationship between primary and secondary transmissions.","Title: Enhancing EFL Learners' English Speaking Performance Through Vlog-Based Digital Multimodal Composing Activities\nYear: 2021\n\nAbstract: Both voice blogs and video blogs have been widely used in various fields, their applications in English as a foreign language (EFL) learning mostly in universities have been mainly to improve students' listening and speaking ability. Relatively few studies have explored how engaging EFL learners in making video blogs might help advance their speaking performance. This study therefore is an investigation of the effects of making voice and video blogs on EFL learners' speaking performance and of their perceptions of vlog-based digital multimodal composing (DMC). Sixty-seven middle school students from Guangdong, China were recruited in this ten-week exploratory study. Data included their pretest and posttest speaking scores, two vlog recordings, questionnaire, and semi-structured interview. The results of this study testified vlog-based DMC's positive influences on speaking performance and indicated that from their first to second vlogs, the students had performed better fluency. Also, video blog-making EFL learners outperformed its counterparts regarding accuracy, while under-performed in fluency in which they demonstrated some significant changes. Pedagogical implications and recommendations for future research are discussed.","Title: Bifurcation analysis of an ecological model with nonlinear state-dependent feedback control by Poincare map defined in phase set\nYear: 2022\n\nAbstract: Ecosystems often need to integrate instantaneous interventions such as biological resource management or integrated pest control. The implementation of interventions, in turn, depends on the state and its change rate of the system, which brings great challenges for the stability and bifurcation analyses. To develop qualitative analysis tech-niques, we propose a predator-prey model with state-dependent pulse interventions, including spraying insecticides and releasing natural enemies, in which the implemen-tation of control measures depends on whether the weighted value of pest density and its change rate reaches the action threshold. We first address the threshold condition for the existence and stability of the boundary periodic solutions and then define a one-parameter family of discrete (Poincare) maps. By analyzing the properties of those discrete maps, we conclude that if there is no interior equilibrium for the system without control measures and the releasing amount of natural enemies is greater than zero, then there is at least one positive periodic solution. While if the system without control measures has an internal equilibrium and only the chemical tactic is applied, then there could be an unstable positive periodic solution near the boundary periodic solution. Consequently, backward bifurcation and bi-stability occur. The analytical techniques developed here could be applied to analyze more generalized models and other fields, including infectious disease control. (c) 2021 Elsevier B.V. All rights reserved.","Title: Assessing work resumption in hospitals during the COVID-19 epidemic in China using multiscale geographically weighted regression\nYear: 2022\n\nAbstract: The resumption of work and production is one of the key issues during the novel coronavirus (COVID-19) post-epidemic phase. We used location-based service data of mobile devices to assess the work resumption of 22,098 hospitals in mainland China. The multiscale influences of the determinants on work resumption in hospitals, including medical-service capacity, human movement, and epidemic severity, were examined using the multiscale geographically weighted regression technique. This study provides a novel insight into the assessment of work resumption in hospitals and its determinants, and is flexible to be extended to evaluate the work resumption of other industries. The findings can introduce helpful information for other countries to implement the strategies of work recovery during the post-epidemic phase.","Title: Traded Control of Human–Machine Systems for Sequential Decision-Making Based on Reinforcement Learning\nYear: 2022\n\nAbstract: Sequential decision-making (SDM) is a common type of decision-making problem with sequential and multistage characteristics. Among them, the learning and updating of policy are the main challenges in solving SDM problems. Unlike previous machine autonomy driven by artificial intelligence alone, we improve the control performance of SDM tasks by combining human intelligence and machine intelligence. Specifically, this article presents a paradigm of a human–machine traded control systems based on reinforcement learning methods to optimize the solution process of sequential decision problems. By designing the idea of autonomous boundary and credibility assessment, we enable humans and machines at the decision-making level of the systems to collaborate more effectively. And the arbitration in the human–machine traded control systems introduces the Bayesian neural network and the dropout mechanism to consider the uncertainty and security constraints. Finally, experiments involving machine traded control, human traded control were implemented. The preliminary experimental results of this article show that our traded control method improves decision-making performance and verifies the effectiveness for SDM problems.","Title: The impact of misspecification of nuisance parameters on test for homogeneity in zero-inflated Poisson model: A simulation study\nYear: 2022\n\nAbstract: Most of the existing methodologies for evaluating heterogeneity in zero-inflated Poisson (ZIP) models are often assuming that the Poisson mean is a function of nuisance parameters. However, these nuisance parameters can be misspecified when performing these methodologies, the validity and the power of the test may be affected. In this article, we primarily focus on investigating the impact of misspecification on the performance of score test for homogeneity in ZIP models. Through an intensive simulation study, we find that: 1) under misspecification, the limiting distribution of the score test statistic under the null no longer follows a distribution. A parametric bootstrap methodology is suggested to use to find the true null limiting distribution of the score test statistic; 2) the power of the test decreases as the number of covariates in the Poisson mean increases. The test with a constant Poisson mean has the highest power, even compared to the test with a well-specified mean. At last, simulation results are applied to the Wuhan Inpatient Care Insurance data which contain excess zeros.","Title: Surveillance video anomaly detection via non-local U-Net frame prediction\nYear: 2022\n\nAbstract: Anomaly detection of surveillance video has become a critical concern in computer vision. It can be used for real-time monitoring and the timely generation of alarms and is widely applied in transportation systems and security systems. An unsupervised anomaly detection method for surveillance video based on frame prediction is implemented in this paper. Generative Adversarial Network (GAN) is used to generate the high-quality frame. Two generators are designed to predict the next future frame. Non-local U-Net is proposed as Generator 1 for frame prediction to predict the global information. Generator 2 obtains more related past frame features and large contour information. The predicted frame and the ground truth are compared to determine anomalies. We take spatial constraints during generative adversarial training, including gradient loss and intensity loss, and time constraints, such as optical flow loss, into account. We experimentally verify that the proposed method has better accuracy in surveillance videos than some other state-of-the-art anomaly detection algorithms.","Title: Secure, Efficient, and Weighted Access Control for Cloud-Assisted Industrial IoT\nYear: 2022\n\nAbstract: In the cloud-assisted Industrial Internet of Things (IIoT), ciphertext-policy attribute-based encryption (CP-ABE) could help the data owner (DO) share his sensitive data via the cloud under self-defined access structures. Among general CP-ABE schemes, the decryption overhead, the key generation cost, and the ciphertext length increase with the number of involved attributes. Additionally, only regular attributes are taking into consideration rather than weighted attributes. In this article, we proposed a secure, efficient, and weighted access control scheme (SEWAC) for cloud-assisted IIoT applications. SEWAC enables the DO to formulate any fine-grained access structure over weighted attributes without making it more complicated. Furthermore, such weighted attributes would not add the length of ciphertext. SEWAC also supports online/offline key generation to alleviate the computational cost of the authority from answering mass key requests in the online phase, while most computational tasks are executed in the offline phase. The heavy decryption overhead is offloaded to the cloud. To ensure the cloud to honestly execute the process of outsourced decryption, we design an efficient batch verification method, which allows the user to spend only three bilinear pairing operations in checking the correctness of batch results. We also give the formal security proof of the proposed scheme. Comprehensive comparisons and implementation results indicate that SEWAC can better achieve weighted access control, compressed ciphertext length, efficient key generation, and the assurance of the outsourced decryption result.","Title: Decentralized control for multi-sensors networked systems with different transmission delays and packet dropouts\nYear: 2022\n\nAbstract: In this paper, the linear quadratic (LQ) optimal decentralized control and stabilization problems are investigated for multi-sensors networked control systems (MSNCSs) with multiple controllers of different information structure. Specifically, for a MSNCS, in view of the packet dropouts and the transmission delays, each controller may access different information sets. To begin with, the sufficient and necessary solvability conditions for the LQ decentralized control problems are developed. Consequently, for the purpose of deriving the optimal decentralized control strategy, an innovative orthogonal decomposition method is proposed to decouple the forward and backward stochastic difference equations (FBSDEs) from the maximum principle. In the following, we show that the optimal decentralized controller can be calculated according to a set of Riccati-type equations. Finally, a stabilizing controller is derived for the stabilization problem.","Title: Optimized Convolutional Neural Network Recognition for Athletes' Pneumonia Image Based on Attention Mechanism\nYear: 2022\n\nAbstract: After high-intensity exercise, athletes have a greatly increased possibility of pneumonia infection due to the immune function of athletes decreasing. Diseases caused by pulmonary bacterial or viral infections can have serious consequences on the health of athletes in a short period of time, and can even lead to their early retirement. Therefore, early diagnosis is the key to athletes' early recovery from pneumonia. Existing identification methods rely too much on professional medical knowledge, which leads to inefficient diagnosis due to the shortage of medical staff. To solve this problem, this paper presents an optimized convolutional neural network recognition method based on an attention mechanism after image enhancement. For the collected images of athlete pneumonia, we first use contrast boost to adjust the coefficient distribution. Then, the edge coefficient is extracted and enhanced to highlight the edge information, and enhanced images of the athlete lungs are obtained by using the inverse curvelet transformation. Finally, an optimized convolutional neural network with an attention mechanism is used to identify the athlete lung images. A series of experimental results show that, compared with the typical image recognition methods based on DecisionTree and RandomForest, the proposed method has higher recognition accuracy for lung images.","Title: Design and motion analysis of double quadrilateral mobile mechanism\nYear: 2022\n\nAbstract: Purpose The purpose of this paper is to propose an overall deformation rolling mechanism based on double four-link mechanism. The double quadrilateral mobile mechanism (DQMM) has two switchable working modes which can be used to traverse different terrains or climb over obstacles. Design/methodology/approach The main body of the DQMM is composed of a double four-link mechanism which sharing a public link and two symmetrical steering platforms which placed at both ends of the four-link mechanism. The steering platforms give the DQMM not only steering ability but also reconnaissance ability which can be achieved by carrying sensors such as cameras on steering platforms. By controlling the deformation of the DQMM, it can switch between two working modes (tracked rolling mode and obstacle-climbing mode) to achieve the functions of rolling and obstacle-climbing. Dynamic simulation model was established to verify the feasibility. Findings Based on the kinematics analysis and simulation results of the DQMM, its moving function is realized by the tracked rolling mode, and the obstacle-climbing mode is used to climb over obstacles in structured terrains such as continuous stairs. The feasibility of the two working modes is verified on a physical prototype. Originality/value The work of this paper is a new exploration of applying \"overall closed moving linkages mechanism\" to the area of small mobile mechanisms. The adaptability of different terrains and the ability of obstacle-climbing are improved by the combination of multi-modes."],"string":"[\n \"Title: A utility-based capacity optimization framework for achieving cooperative diversity in the hierarchical converged heterogeneous wireless networks\\nYear: 2008\\n\\nAbstract: A hierarchical convergence mechanism for the heterogeneous wireless communication system via the heterogeneous cooperative relay node is presented in this paper, in which the techniques of cooperative communication and wireless relay are utilized to improve performances of the individual user and the overall converged networks. In order to evaluate the benefits of the proposal, a utility-based capacity optimization framework for achieving the heterogeneous cooperative diversity gain is proposed. The heterogeneous cooperative capacity, relay selection and power allocation theoretical models are derived individually. The joint optimization model for relay selection and power allocation is presented as well. Owing to the computation complexity, the sub-optimal cooperative relay selection algorithm, the sub-optimal power allocation algorithm and the sub-optimal joint algorithm are determined to approach the maximum overall networks' spectrum efficiency. These proposed algorithms are designed in conformance to guarantee the equivalent transmission rates of the different wireless access networks. The simulation results demonstrate that the utility-based capacity model is available for the heterogeneous cooperative wireless communication system, and the proposed algorithms can improve performances by achieving the cooperative gain and taking full advantage of the cross-layer design. Copyright © 2008 John Wiley & Sons, Ltd.\",\n \"Title: Detecting for the aerial small target in infrared image based on the correlation coefficients of nonsubsampled contourlet transform.\\nYear: 2012\\n\\nAbstract: In order to solve the practical problem of the infrared small target's detecting in the sky, a detecting algorithm based on NSCT (nonsubsampled contourlet transform) is proposed. Firstly, taking advantage of the excellent property of the transform, this algorithm analyses the different property of the NSCT coefficients of noise, background edge and signal, then computes the normalized correlation coefficients between scales for the transform coefficients. Subsequently, according to the adaptive method of threshold, the coefficients of background edge and noise are suppressed and then the image which includes the enhanced target is acquired by the inverse transform. In the end, taking the target area into account, the reconstructed image is segmented and the final detecting result is acquired by considering the position correlation of the target between frames. Experimental results show that the method given by this paper can detect small target accurately. Compared with some traditional method, it has certain advantage in background suppressing and can acquire high SNR (signal noise ratio) value. © 2012 IEEE.\",\n \"Title: Management Motivation and Earnings Management Methods\\nYear: 2013\\n\\nAbstract: In this paper, we study the effectiveness of the management motivations on earnings management methods based on thousands of samples between 2006 and 2011. The empirical results indicate that Real Earnings Management is used to manipulate the earnings in order to turn a profit, avoid loss, refinance, and change executives. The companies with higher executive compensations intend to use REM. However, making big profits by using Real Earnings Management activities is not popular because the capital market in China is not perfect enough.\",\n \"Title: A verifiable secret sharing scheme without dealer in vector space\\nYear: 2011\\n\\nAbstract: Based on the (+, +) homomorphism property of shamir's (t, n) secret sharing scheme, Harn and Lin proposed a (n, t, n) secret sharing scheme, in which each shareholder also acts as a dealer and the master secret was decided by the sub-secret of each shareholder. But this scheme is only suited to the threshold access structure. In this paper, we firstly define the (+, +) homomorphism property of secret sharing scheme in vector space. Then we extend the idea of (n, t, n) secret sharing scheme to vector space access structure, and define the secret sharing scheme without dealer in vector space and propose a verifiable secret sharing scheme without dealer in vector space based on the intractability of discrete logarithm. Compared with Harn and Lin's (n, t, n) secret sharing scheme, the proposed scheme is more general and is applied more widely since it is suited to vector space access structure.\",\n \"Title: Synthesis and Characterization of Eco-friendly Composite: Poly(Ethylene Glycol)-Grafted Expanded Graphite/Polyaniline.\\nYear: 2011\\n\\nAbstract: In this paper, synthesis and characterization of poly(ethylene glycol)grafted expanded graphite/polyaniline (PEG-grafted EG/PANi) as a novel eco-friendly composite material was reported. EG as substrate prepared from expandable graphite was firstly synthesized by in-situ polymerization at the presence of aniline (An) to obtain EG/PANi, and then graft polymerization with as-prepared PEG-grafted PANi (PEG-g-PANi) composite under no tough conditions. Structural characteristics of the products were evaluated by infrared spectrum (ER), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The experimental results have shown that the product of PEG-grafted EG/PANi composite were synthesized by facile method.\",\n \"Title: The Implementation of XPDL Workflow Verification Service Based on SaaS\\nYear: 2010\\n\\nAbstract: The process sub-model is the core of workflow model, verifying process sub-model before deployment can reduce the cost of shutdown, inspection and repair at run-time. This paper proposes verification algorithms, which focus on structural errors of process sub-model, and those algorithms will use the characteristics of the extended Petri net discussed in this paper. Simultaneously, this paper explains how to design a XPDL Validator based on SaaS and it emphasis on mapping XPDL process definition to extended Petri net.\",\n \"Title: Cooperative Multi-Antenna Relaying In Heterogeneous Networks\\nYear: 2009\\n\\nAbstract: In this paper, we investigate the performance of heterogeneous networks with multi-antenna cooperative relays. Specifically, threshold-based maximum ratio combining (MRC) and selection combining (SC) schemes are adopted for decoding at the relays and the end-to-end (EM) error rate performance is analyzed by assuming a Nakagami channel model. Numerical results show that the deployment of multi-antennas can reduce the number of required relay nodes, and thus significantly reduce the system cost. On the other hand, the selection of optimal decoding threshold depends on the number of relay nodes, number of antennas, as well as the average SNR value at the receiver. It is also demonstrated that when the BER requirement is not high, the SC relaying scheme is sufficient to provide satisfactory performance, such that the complexity of relays can be effectively reduced.\",\n \"Title: Next-generation sequencing data processing: Analysis of unmapped reads and extremely high mapped peaks.\\nYear: 2012\\n\\nAbstract: Next-generation sequencing (NGS) and its applications are widely used in studying gene regulation and epigenetic mechanisms due to its decreasing cost and high throughput. Here we used MNase-seq technology to determine the nucleosome positions in human erythroleukemia k562 cells by direct sequencing of nucleosome ends with the SOLiD high-throughput sequencing technique. However, during the reads mapping and data pre-analysis steps, only 40% of the sequenced reads can be mapped to the reference genome hg19 and there are some extremely high peaks (EHPs) in the profiles of mapped reads on the reference genome. Mathematical models were developed to analyze the unmapped reads and nearly 25.3% of the unmapped reads were found due to genome variants, base-calling errors and gaps of the reference genome. We also investigated EHPs and proposed methods to deal with the EHPs for the downstream data analysis. © 2012 IEEE.\",\n \"Title: Consensus analysis for a class of stochastic PSO algorithm\\nYear: 2014\\n\\nAbstract: Most of the existing results mainly concentrate on the convergence analysis and stability analysis of Particle Swarm Optimization (PSO) in the presence of @w@?[0, 1]. However, few existing works discuss the convergence and the stability of time-varying stochastic PSO swarm system from the perspective of the consensus. This paper firstly proposes an improved consensus protocol on the basis of the velocity and position equations of the canonical PSO algorithm, and transforms the dynamical PSO system into one new linear discrete-time system including random variables. Finally several important theorems concerning the mean square consensus are provided according to the existing important results of nonnegative random matrices, stability theory of large-scale system, etc. Furthermore, the boundary of consensus region is given to better select the parameters in PSO algorithm. Finally, numerical simulation results chiefly discuss the convergence analysis of each particle and demonstrate the effectiveness of the above-mentioned theorems.\",\n \"Title: Internet addiction among Chinese adolescents: The effect of parental behavior and self-control.\\nYear: 2014\\n\\nAbstract: •Adolescents with IA experience more unfavorable parental behavior than the non-IA.•Adolescents with IA have lower capacity of self-control than the non-IA.•Parental behavior and self-control both predict Internet addiction directly.•Self-control also acts as a mediator between parental behavior and Internet addiction.•The results are discussed from the view of Chinese Confucian filial piety.\",\n \"Title: Time-Aware Collaborative Filtering for Recommender Systems.\\nYear: 2012\\n\\nAbstract: Traditional collaborative filtering algorithms only take into account the users' historical ratings, which ignore the user-interest drifting and item-popularity changing over a long period of time. Aiming to the above problems, a time-aware collaborative filtering algorithm is proposed, which tracks user interests and item popularity over time. We extend the widely used neighborhood based algorithms by incorporating two kinds of temporal information and develop an improved algorithm for making timely recommendations. Experimental results show that the proposed approach can efficiently improve the accuracy of the prediction.\",\n \"Title: The Multiple Population Co-evolution PSO Algorithm.\\nYear: 2014\\n\\nAbstract: In order to overcome the standard particle swarm optimization algorithm which is easily trapped in local minima and optimize the shortcoming of low precision, this paper proposed a way which can make multiple information exchange between particles come true: the multiple population co-evolution PSO algorithm. This paper proposes a multiple population co-evolutionary algorithm to achieve communication among populations, and then show the feasibility and effectiveness of this algorithm through experiments.\",\n \"Title: Energy-efficient resource allocation for OFDMA two-way relay networks with imperfect CSI\\nYear: 2015\\n\\nAbstract: Most of the existed works on the radio resource allocation (RRA) problem commonly assume the channel-state information (CSI) can be perfectly obtained by the transmission source. However, such assumption is not practical in the realistic wireless systems. In this work, we consider the practical implementation issues of resource allocation in orthogonal frequency division multiple access (OFDMA) two-way relay networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, only the estimated channel status is known by the source. In this context, a joint optimization of subcarrier pairing and allocation, relay selection, and transmit power allocation is formulated in OFDMA two-way amplify-and-forward relay networks. Moreover, the objective of this work is to minimize the energy consumption of the overall system. Further, to ensure the quality of service (QoS) or data rate requirement, the energy consumption must be minimized without compromising the QoS. Therefore, by applying convex optimization techniques, energy-efficient algorithms are developed with the objective to minimize the total transmit power with guaranteeing the required data rates. Through simulation studies, energy consumption performance of the systems under the proposed schemes is investigated. It can be observed that our proposed scheme can improve the energy consumption performance of the considered system.\",\n \"Title: A combinatorial double auction based resource allocation mechanism with multiple rounds for geo-distributed data centers\\nYear: 2016\\n\\nAbstract: With the explosion of application of big data, it becomes inefficient and infeasible to process big data stream by using conventional data service infrastructure and management system. Cloud computing platform having multiple geo-distributed data centers is expected to be the most efficient platform to process the big data stream. In this paper, a multi-round combinational double auction based mechanism is proposed to allocate the resources of geo-distributed data centers to multiple users with large data stream processing tasks. This mechanism combines the advantages of combinatorial auction and double auction. In the proposed mechanism, the different types of VMs can be integrated into a bundle to be bid. The auction is double and conducted from both users and data centers. Different from existed double auctions, the QoS level is taken into consideration. In addition, the multiple rounds mode is adopted, so the failed users and data centers have the chance to adjust bids and asks to participate next auction round, increasing the ratio of successful transactions. Simulation results validate the effectiveness of the proposed mechanism.\",\n \"Title: Quantum Game Theory for Beam Alignment in Millimeter Wave Device-to-Device Communications.\\nYear: 2016\\n\\nAbstract: In this paper, the problem of optimized beam alignment for wearable device-to-device (D2D) communications over millimeter wave (mmW) frequencies is studied. In particular, a noncooperative game is formulated between wearable communication pairs that engage in D2D communications. In this game, wearable devices acting as transmitters autonomously select the directions of their beams so as to maximize the data rate to their receivers. To solve the game, an algorithm based on best response dynamics is proposed that allows the transmitters to reach a Nash equilibrium in a distributed manner. To further improve the performance of mmW D2D communications, a novel quantum game model is formulated to enable the wearable devices to exploit new quantum directions during their beam alignment so as to further enhance their data rate. Simulation results show that the proposed game-theoretic approach improves the performance, in terms of data rate, of about 7 5 % compared to a uniform beam alignment. The results also show that the quantum game model can further yield up to 2 0 % improvement in data rates, relative to the classical game approach.\",\n \"Title: An Improved Method Of Compensating The Mutual Coupling Effect For Aperture Synthesis Radiometers\\nYear: 2016\\n\\nAbstract: In aperture synthesis radiometers (ASRs), the mutual coupling effect between antennas is a key problem, which degrades the performance of ASRs and should be compensated. In this paper, an improved compensation method is proposed for ASRs, which is based on the receiving mutual impedance. The proposed method is verified by a one-dimension 5-channel L-band ASR. The experimental results show that the proposed method is superior over the existing method based on the transmitting mutual impedance, and is more appropriate to compensate the mutual coupling effect for ASRs.\",\n \"Title: Energy Optimization by Flow Routing Algorithm in Data Center Network Satisfying Deadline Requirement.\\nYear: 2016\\n\\nAbstract: Recently, the data center networks consume a large amount of energy, therefore, the energy saving is becoming increasingly important. Most previous works consolidate flows into as few switches as possible, which is not suitable for network-limited flows which require huge bandwidth to finish traffic transmission within deadline. To solve the challenge of energy-efficient path and deadline satisfied for network-limited flows, in this paper, we formulate the routing problem as a 0-1 integer programming problem, and propose a two-phase energy-efficient flow routing algorithm. Both energy saving and link utilization maximization are considered. Simulation results show that our algorithm achieves better performance in terms of energy saving, link utilization, as well as the active switch ratio.\",\n \"Title: Dynamic Online Consumer Trust Forming Mechanism Research Based On Beijing, China\\nYear: 2016\\n\\nAbstract: This research identifies a number of key factors related to online consumer trust and establishes a model based on the System Dynamic method to find out the relationships between these factors and trust. This paper provides several contributions. Firstly it reviews the previous works of online trust and identifies the major online trust building factors which mainly consists of business factors, consumer factors, commodities factors, and e-commerce environment factors. Secondly, it builds an online consumer trust forming mechanism model based on the analysis of literature reviews. Thirdly, the causal relationship between the forming factors and consumer trust was analyzed by the simulation of system dynamic method.\",\n \"Title: Cooperative Receiver For Ambient Backscatter Communications With Multiple Antennas\\nYear: 2017\\n\\nAbstract: In ambient backscatter communications (AmBC), a backscatter device can harvest power from ambient RF signals and modulate its information symbols over the ambient carriers without using complex RF transmitter. Conventional receiver design for AmBC focuses on tackling the direct link interference from the RF source. In this paper, a novel receiver, which is called cooperative receiver, is proposed to recover signals not only from the ambient backscatter device (A-BD), but also from the RF source. We first study the optimal maximum-likelihood (ML) detection for such system. Then, by exploiting the structural property of the system model, linear detectors and successive interference cancellation (SIC) based detectors are proposed. We also derive the closed-form bit error rate (BER) expressions for both ML detection and the proposed SIC algorithms. Finally, extensive numerical results show that the existence of backscattered signal in the considered system can significantly enhance the ML detection performance of the source signal, and the proposed SIC-based detectors can achieve near-ML detection performance for typical application scenarios.\",\n \"Title: A Large Scale Data Transmission Control Mechanism across Data Centers\\nYear: 2017\\n\\nAbstract: With the rapid development of the information technology, the scale of data is quickly increasing, and the more and more data centers are built by research institutions or commercial organizations. In order to collect and analyze the data, the end-to-end transmission for the large scale of data across data centers need be implemented. However, the existing works are mainly based on TCP or UDP, and can not meet the actual demand. For TCP, the transmission efficiency is low due to the frequent three-way handshake and the mismatch between the sending window and the link capacity. For UDP, the transmission is unreliable and the compatibility of the improved methods is poor. In order to solve the above problems, an end-to-end transmission control model based on session management is proposed. In this model, two kinds of agents and the session management mechanism are adopted to localize TCP three-way handshake in the data center and improve the transmission efficiency of the large scale data across data centers, and the improved UDP is used to the long-distance transmission between the agents in order to enhance the reliability of the end-to-end transmission. The experimental results show that the transmission control mechanism presented in this paper can effectively reduce the transmission delay and improve the efficiency of transmission for the large scale data.\",\n \"Title: Cooperative Ambient Backscatter Communications for Green Internet-of-Things.\\nYear: 2018\\n\\nAbstract: Ambient backscatter communication (AmBC) enables a passive backscatter device to transmit information to a reader using ambient RF signals, and has emerged as a promising solution to green Internet-of-Things (IoT). Conventional AmBC receivers are interested in recovering the information from the ambient backscatter device (A-BD) only. In this paper, we propose a cooperative AmBC (CABC) system in w...\",\n \"Title: A Dual-Tree Complex Wavelet Transform Based Convolutional Neural Network for Human Thyroid Medical Image Segmentation\\nYear: 2018\\n\\nAbstract: This research proposes a novel dual-tree complex wavelet transform based Convolutional Neural Network (WCNN) to perform organ tissue segmentation from medical images. Accurate and efficient segmentation on the medical image of human organ is a critical step towards disease diagnosis. For medical image segmentation tasks, conventional Convolutional Neural Networks (CNNs) are: 1) inclined to ignore crucial texture information of the image due to the limitations of typical pooling approaches, and 2) insufficiently robust to noise. To overcome the obstacles, a spectral domain transformation technique is adopted in the CNN. Specifically, a dual-tree complex wavelet pooling layer is concatenated to the traditional pooling process in a CNN. By using wavelet decomposition, the image becomes scalable in the spatial direction, allowing accurate recognition of textures. The WCNN decomposes the image into a number of wavelet subbands, and reduces noisy data by filtering out high-frequency subbands. The performance of WCNN is tested on standard image classification datasets, and applied for human thyroid optical coherence tomography (OCT) image segmentation. Compared to the traditional CNNs using max pooling, experimental results demonstrate that the WCNN approach obtains outstanding consistency and accuracy in the image segmentation domain.\",\n \"Title: Medical Image Synthesis with Generative Adversarial Networks for Tissue Recognition\\nYear: 2018\\n\\nAbstract: This paper presents an adversarial learning-based approach to synthesize medical images for medical image tissue recognition. The performance of medical image recognition models highly depends on the representativeness and sufficiency of training samples. The high expense of collecting large amounts of practical medical images leads to a demand of synthesizing image samples. In this research, generative adversarial networks (GANs), which consist of a generative network and a discriminative network, are applied to develop a medical image synthesis model. Specifically, deep convolutional GANs (DCGANs), Wasserstein GANs (WGANs), and boundary equilibrium GANs (BEGANs) are implemented and compared to synthesize medical images in this research. Convolutional neural networks (CNNs) are applied in the GAN models, which can capture feature representations that describe a high level of image semantic information. Then synthetic images are generated by employing the generative network mapping from random noise. The effectiveness of the generative network is validated by a discriminative network, which is trained to detect the synthetic images from real images. Through a minimax two-player game, the generative and discriminative networks can train each other. The generated synthetic images are used to train a CNN classification model for tissue recognition. Through the experiments with the synthetic images, the tissue recognition accuracy achieves 98.83%, which reveals the effectiveness and applicability of synthesizing medical images through the GAN models.\",\n \"Title: Label-Assisted Transmission for Short Packet Communications: A Machine Learning Approach.\\nYear: 2018\\n\\nAbstract: Short packet communications (SPC) will play an important role in future Internet-of-Things networks. Conventional pilot-assisted transmission (PAT) needs significant overhead to obtain accurate channel state information (CSI) for further symbol detection and bit recovery, thereby reducing the spectral efficiency of the transmission. In this paper, a machine learning framework called Label-Assisted...\",\n \"Title: Parallel distributed computing based wireless sensor network anomaly data detection in IoT framework.\\nYear: 2018\\n\\nAbstract: To reduce the energy consumption of wireless sensor networks (WSNs) and prolong the network lifetime, non-uniform clustering routing (DUCF) of WSNs based on distributed fuzzy logic interference is proposed. DUCF protocol fully considers the residual energy of node, the node degree and distance from the base station. Fuzzy rule is formulated based on experience and the probability of node being elected as cluster head and the size of cluster are obtained through fuzzy interference system. DUCF protocol forms non-uniform cluster and further balances the energy consumption among cluster heads. Simulation result indicates that the performances of DUCF protocol in network lifetime and energy consumption are superior to that of LEACH, CHEF and EAUCF protocol.\",\n \"Title: Predictive Deployment of UAV Base Stations in Wireless Networks: Machine Learning Meets Contract Theory\\nYear: 2018\\n\\nAbstract: In this paper, a novel framework is proposed to enable a predictive deployment of unmanned aerial vehicles (UAVs) as temporary base stations (BSs) to complement ground cellular systems in face of downlink traffic overload. First, a novel learning approach, based on the weighted expectation maximization (WEM) algorithm, is proposed to estimate the user distribution and the downlink traffic demand. Next, to guarantee a truthful information exchange between the BS and UAVs, using the framework of contract theory, an offload contract is developed, and the sufficient and necessary conditions for having a feasible contract are analytically derived. Subsequently, an optimization problem is formulated to deploy an optimal UAV onto the hotspot area in a way that the utility of the overloaded BS is maximized. Simulation results show that the proposed WEM approach yields a prediction error of around 10%. Compared with the expectation maximization and k-mean approaches, the WEM method shows a significant advantage on the prediction accuracy, as the traffic load in the cellular system becomes spatially uneven. Furthermore, compared with two event-driven deployment schemes based on the closest-distance and maximal-energy metrics, the proposed predictive approach enables UAV operators to provide efficient communication service for hotspot users in terms of the downlink capacity, energy consumption and service delay. Simulation results also show that the proposed method significantly improves the revenues of both the BS and UAV networks, compared with two baseline schemes.\",\n \"Title: Constellation Learning-Based Signal Detection for Ambient Backscatter Communication Systems\\nYear: 2019\\n\\nAbstract: Ambient backscatter communication (AmBC) is a promising solution to energy-efficient and spectrum-efficient Internet of Things with stringent power and cost constraints. In an AmBC system, recovering the tag information at the reader, however, is a challenging task due to the difficulty in acquiring the relevant channel-state information (CSI). To eliminate the need to estimate the CSI, in this paper, we propose a label-assisted transmission framework, in which two known labels are transmitted from the tag before data transmission. By exploring the received signal constellation information, we propose modulation-constrained expectation maximization algorithm, based on which two detection methods are developed. One method, referred to as constellation learning with labeled signals, learns the parameters by clustering the labeled signals and recovers the unlabeled signals by the learnt parameters. The other method, referred to as constellation learning with labeled and unlabeled signals, uses all received signals in clustering. Efficient initialization techniques are provided for the two clustering algorithms. Finally, extensive simulation results show that the proposed constellation learning methods achieve comparable performance as the optimal detector with perfect CSI.\",\n \"Title: Exploiting Multiple Antennas for Cognitive Ambient Backscatter Communication\\nYear: 2019\\n\\nAbstract: Cognitive ambient backscatter communication is a novel spectrum sharing paradigm, in which the backscatter system shares not only the same spectrum, but also the same radio-frequency source with the legacy system. Conventional energy detector (ED) suffers from severe error floor problem due to the existence of co-channel direct link interference (DLI) from the legacy system. In this paper, novel error-floor-free detectors are proposed to tackle the DLI using multiple receive antennas at the reader. First, beamforming-assisted ED and likelihood-ratio-based detector are proposed for backscatter symbol detection when the reader has perfect channel state information (CSI). Then a novel statistical clustering framework is proposed for joint CSI feature learning and backscatter symbol detection. Extensive simulation results have shown that the proposed methods can significantly outperform the conventional ED. In addition, the proposed clustering-based methods perform comparably as their counterparts with perfect CSI.\",\n \"Title: Multi-Antenna Beamforming Receiver for Cognitive Ambient Backscatter Communications.\\nYear: 2018\\n\\nAbstract: Cognitive ambient backscatter communication (Am-BC) is a novel spectrum sharing paradigm for green Internet of Things, in which the backscatter system shares not only the same spectrum, but also the same radio frequency (RF) source with the legacy system. The conventional energy detector (ED) suffers from a severe error floor problem due to the existence of co-channel direct link interference (DLI) from the legacy system. In this paper, novel error-floor-free detectors are proposed to tackle the DLI through multi-antenna receive beamforming. A novel statistical clustering framework is proposed for joint channel state information (CSI) learning and backscatter symbol detection. Extensive simulation results have shown that the proposed methods can significantly outperform the conventional ED, and verified that the proposed clustering-based method achieves performance comparable to that of the perfect CSI cases.\",\n \"Title: Clustering-Inspired Signal Detection for Ambient Backscatter Communication Systems.\\nYear: 2018\\n\\nAbstract: In ambient backscatter communication (AmBC), it is a challenging task to recover the tag information at the reader due to the difficulty in obtaining the relevant channel state information (CSI). In this paper, we translate the signal detection problem into a clustering problem, for which two known labels are transmitted from the tag as the prior knowledge to assist clustering initialization and signal detection. By exploiting the received signals directly, two clustering-inspired detection methods are proposed, one is called clustering with labeled signals (CLS), and the other is referred to as clustering with labeled and unlabeled signals (CLUS). Both methods are developed based on the proposed modulation-constrained (MC) Gaussian mixture model (GMM). Finally, extensive simulation results show that the proposed methods only have small gaps compared with the optimal detection with perfect CSI.\",\n \"Title: Network Formation Game for Multi-Hop Wearable Communications over Millimeter Wave Frequencies.\\nYear: 2017\\n\\nAbstract: In this paper, the use of multi-hop, device-to-device communications over millimeter wave (mmW) frequencies is studied for effective wearable communications. In particular, the problem of uplink communications is studied for a wearable network in which each wearable device seeks to form a multi-hop path over mmW to access a cellular base station, in order to overcome the high channel loss caused by mmW attenuation and blockage. To analyze the optimal selection of the uplink path, a network formation game is formulated between all wearable devices. In this game, each wearable device autonomously chooses the uplink path that maximizes its utility function that captures the tradeoff between rate, delay, and privacy. To solve this game, a novel algorithm that combines best response dynamics with mixed-strategy techniques is proposed to find the mixed Nash network, which corresponds to a stable uplink structure at which no wearable device can improve its utility by changing its network formation decision. Simulation results show that the proposed game approach improves the average utility per wearable device of over 14% and 78%, respectively, compared with the direct transmission and the nearest next-hop schemes.\",\n \"Title: A Clustering Detector for Spatial Modulation System\\nYear: 2018\\n\\nAbstract: Spatial modulation (SM) is regarded as a promising multiple-input multiple-output (MIMO) technique since it exploits the additional spatial domain for transmitting information. For transceiver design in SM, the traditional schemes first estimate the channel state information (CSI) based on pilots for further decoding, which introduce significant overhead, thereby reducing the spectral efficiency of the transmission. In this paper, to avoid the channel estimation, we convert the signal detection problem into a cluster problem for SM system. Utilizing the inter-structure of the SM system, we propose a structured Gaussian mixture model (SGMM) with a reduced number of parameters to model the received signals. We also develop an SGMM-based expectation maximization algorithm (SGMM-EM) to cluster the received signals. The complexity of SGMM-EM algorithm is reduced significantly compared with traditional clustering algorithm. After clustering all the received signals, a label mapping method is developed to map each transmitted symbol to one of the clusters. Simulation results show that, with only a small number of iterations, the performance of our proposed scheme approaches to that of the optimal receiver with perfect CSI.\",\n \"Title: Detection of Type, Blended Ratio, and Mixed Ratio of Pu'er Tea by Using Electronic Nose and Visible/Near Infrared Spectrometer.\\nYear: 2019\\n\\nAbstract: The objective of this study was to find an intelligent and fast method to detect the type, blended ratio, and mixed ratio of ancient Pu'er tea, which is significant in maintaining order in the Pu'er tea industry. An electronic nose (E-nose) and a visible near infrared spectrometer (VIS/NIR spectrometer) were applied for tea sampling. Feature extraction was conducted using both the traditional method and a convolutional neural network (CNN) technique. Linear discriminant analysis (LDA) and partial least square regression (PLSR) were applied for pattern recognition. After sampling while using the traditional method, the analysis of variance (ANOVA) results showed that the mean differential value of each sensor should be selected as the optimal feature extraction method for E-nose data, and raw data comparison results showed that 19 peak/valley values and two slope values were extracted. While the format of E-nose data was in accord with the input format for CNN, the VIS/NIR spectrometer data required matrixing to meet the format requirements. The LDA and PLSR analysis results showed that CNN has superior detection ability, being able to acquire more local features than the traditional method, but it has the risk of mixing in redundant information, which can act to reduce the detection ability. Multi-source information fusion (E-nose and VIS/NIR spectrometer fusion) can collect more features from different angles to improve the detection ability, but it also contains the risk of adding redundant information, which reduces the detection ability. For practical detection, the type of Pu'er tea should be recognizable using a VIS/NIR spectrometer and the traditional feature extraction method. The blended ratio of Pu'er tea should also be identifiable by using a VIS/NIR spectrometer with traditional feature extraction. Multi-source information fusion with traditional feature extraction should be used if the accuracy requirement is extremely high; otherwise, a VIS/NIR spectrometer with traditional feature extraction is preferred.\",\n \"Title: Resource Allocation for Symbiotic Radio System With Fading Channels.\\nYear: 2019\\n\\nAbstract: In this paper, we investigate the resource allocation problem for the symbiotic radio system, in which the passive backscatter transmission is parasitic in the primary transmission, and the cooperative receiver simultaneously detects the signals transmitted from the active primary transmitter (PT) and the backscatter device (BD). In particular, channel fading is considered, and the ergodic weighted sum rate of the primary and backscatter transmissions is maximized by jointly optimizing the transmit power at the PT and the reflection coefficient at the BD under either long-term or short-term transmit-power constraint over the fading states. Two practical transmission setups are considered, where the relationship between the primary and backscatter transmissions is either commensal or parasitic. For the commensal setup, we fix the reflection coefficient as the maximum value and derive the optimal power allocation scheme based on the standard convex optimization procedure. For the parasitic setup, the weighted sum-rate maximization problem is non-convex, and we resort to the concave-convex procedure to derive a suboptimal solution. Simulation results demonstrate that in the commensal setup, the BD may realize transmission while causing no harmful interference to the primary system; in the parasitic setup, a higher backscatter data rate can be achieved through slightly sacrificing the primary transmission rate.\",\n \"Title: Backscatter-NOMA: A Symbiotic System of Cellular and Internet-of-Things Networks.\\nYear: 2019\\n\\nAbstract: Non-orthogonal multiple access (NOMA) is envisioned as a key technology to enhance the spectrum efficiency for 5G cellular networks. Meanwhile, ambient backscatter communication is a promising solution to the Internet of Things (IoT), due to its high spectrum efficiency and power efficiency. In this paper, we are interested in a symbiotic system of cellular and IoT networks and propose a backscatter-NOMA system, which incorporates a downlink NOMA system with a backscatter device (BD). In the proposed system, the base station (BS) transmits information to two cellular users according to the NOMA protocol, while a BD transmits its information over the BS signals to one cellular user using the passive radio technology. In particular, if the BS only serves the cellular user that decodes BD information, the backscatter-NOMA system turns into a symbiotic radio (SR) system. We derive the expressions of the outage probabilities and the ergodic rates and analyze the corresponding diversity orders and slopes for both backscatter-NOMA and SR systems. Finally, we provide the numerical results to verify the theoretical analysis and demonstrate the interrelationship between the cellular networks and the IoT networks.\",\n \"Title: A Latent-Dirichlet-Allocation Based Extension For Domain Ontology Of Enterprise'S Technological Innovation\\nYear: 2019\\n\\nAbstract: This paper proposed a method for building enterprise's technological innovation domain ontology automatically from plain text corpus based on Latent Dirichlet Allocation (LDA). The proposed method consisted of four modules: 1) introducing the seed ontology for domain of enterprise's technological innovation, 2) using Natural Language Processing (NLP) technique to preprocess the collected textual data, 3) mining domain specific terms from document collections based on LDA, 4) obtaining the relationship between the terms through the defined relevant rules. The experiments have been carried out to demonstrate the effectiveness of this method and the results indicated that many terms in domain of enterprise's technological innovation and the semantic relations between terms are discovered. The proposed method is a process of continuously cycles and iterations, that is the obtained objective ontology can be re-iterated as initial seed ontology. The constant knowledge acquisition in the domain of enterprise's technological innovation to update and perfect the initial seed ontology.\",\n \"Title: An Open Source Modeling Framework for Interdependent Energy-Transportation-Communication Infrastructure in Smart and Connected Communities\\nYear: 2019\\n\\nAbstract: Infrastructure in future smart and connected communities is envisioned as an aggregate of public services, including energy, transportation, and communication systems, all intertwined with each other. The intrinsic interdependency among these systems may exert the underlying influence on both design and operation of the heterogeneous infrastructures. However, few prior studies have tapped into the interdependency among these systems in order to quantify their potential impacts during standard operation. In response to this, this paper proposes an open-source, flexible, integrated modeling framework suitable for designing coupled energy, transportation, and communication systems and for assessing the impact of their interdependencies. First, a novel multi-level, multi-layer, multi-agent approach is proposed to enable flexible modeling of the interconnected systems. Then, for the framework's proof of concept, preliminary component and system-level models for different systems are designed and implemented using Modelica, an equation-based object-oriented modeling language. Finally, three case studies of gradually increasing complexity are presented (energy, energy + transportation, and energy + transportation + communication) to evaluate the interdependencies among the three systems. Quantitative analyses show that the deviation of the average velocity on the road can be 10.5% and the deviation of the power drawn from the grid can be 7% with or without considering the transportation and communication system at the peak commute time, indicating the presence of notable interdependencies. The proposed modeling framework also has the potential to be further extended for various modeling purposes and use cases, such as dynamic modeling and optimization, resilience analysis, and integrated decision making in future connected communities.\",\n \"Title: Cooperative Ambient Backscatter System: A Symbiotic Radio Paradigm for Passive IoT\\nYear: 2019\\n\\nAbstract: Cooperative ambient backscatter system is a novel symbiotic radio paradigm, in which the passive backscatter transmission shares not only the same spectrum but also the same radio-frequency source with the active primary transmission. By considering the unique features of the ambient backscatter system, three practical symbiotic transmission schemes are proposed, in which the relationships between the primary and backscatter transmissions are commensal, parasitic, and competitive, respectively. The achievable rates for both primary and backscatter transmissions are derived for particular fading state. Then, optimal power allocation is obtained for each transmission scheme under the average power constraint. Simulation results are provided to corroborate theoretical studies.\",\n \"Title: A review of improved extreme learning machine methods for data stream classification\\nYear: 2019\\n\\nAbstract: Classification is a hotspot in data stream mining and has gained increasing interest from various research fields. Compared with traditional data stream classification methods, Extreme Learning Machine (ELM) has attracted much attention because of its efficiency and simplicity, which inspired the development of many improved ELM algorithms that have been proposed in the past few years. This paper mainly reviews the current state of ELM used to classify data streams and its variants. First, we introduce the principles of ELM and the existing problems of data stream classification. Then we provide an overview of various improvements made to ELM, which further improves its stability, accuracy and generalization ability and present the practical applications of ELM used in data stream classification. Finally, the paper highlights the existing problems of ELM used for data stream mining and development prospects of ELM in the future.\",\n \"Title: Intelligent User Association for Symbiotic Radio Networks using Deep Reinforcement Learning.\\nYear: 2019\\n\\nAbstract: In this paper, we are interested in \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">symbiotic radio networks</italic>\\n (SRNs), in which an \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Internet-of-Things</italic>\\n (IoT) network parasitizes in a primary cellular network to achieve spectrum-, energy-, and infrastructure-efficient communications. Each IoT device transmits its own information by backscattering the signals from the primary network without using active \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">radio-frequency</italic>\\n (RF) transmitter chain. We consider the symbiosis between the cellular network and the IoT network and focus on the user association problem in SRN. Specifically, the \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">base station</italic>\\n (BS) in the primary network serves multiple cellular users using \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">time division multiple access</italic>\\n (TDMA) and each IoT device is associated with one cellular user for information transmission. The objective of user association is to link each IoT device to an appropriate cellular user by maximizing the sum rate of all IoT devices. However, the difficulty in obtaining the full real-time channel information makes it difficult to design an optimal policy for this problem. To overcome this issue, we propose two \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">deep reinforcement learning</italic>\\n (DRL) algorithms, both use historical information to infer the current information in order to make appropriate decisions. One algorithm, referred to as centralized DRL, makes decisions for all IoT devices at one time with globally available information. The other algorithm, referred to as distributed DRL, makes a decision only for one IoT device at one time using locally available information. Finally, simulation results show that the two proposed DRL algorithms achieve performance comparable to the optimal user association policy which requires perfect real-time information, and the distributed DRL algorithm has the advantage of scalability.\",\n \"Title: Distributed Generative Adversarial Networks for mmWave Channel Modeling in Wireless UAV Networks\\nYear: 2021\\n\\nAbstract: In this paper, a novel framework is proposed to enable air-to-ground channel modeling over millimeter wave (mmWave) frequencies in an unmanned aerial vehicle (UAV) wireless network. First, an effective channel estimation approach is developed to collect mmWave channel information allowing each UAV to train a local channel model via a generative adversarial network (GAN). Next, in order to share the channel information between UAVs in a privacy-preserving manner, a cooperative framework, based on a distributed GAN architecture, is developed to enable each UAV to learn the mmWave channel distribution from the entire dataset in a fully distributed approach. The necessary and sufficient conditions for the optimal network structure that maximizes the learning rate for information sharing in the distributed network are derived. Simulation results show that the learning rate of the proposed GAN approach will increase by sharing more generated channel samples at each learning iteration, but decrease given more UAVs in the network. The results also show that the proposed GAN method yields a higher learning accuracy, compared with a standalone GAN, and improves the average rate for UAV downlink communications by over 10%, compared with a baseline real-time channel estimation scheme.\",\n \"Title: Semi-Supervised Learning for Channel Charting-Aided IoT Localization in Millimeter Wave Networks\\nYear: 2021\\n\\nAbstract: In this paper, a novel framework is proposed for channel charting (CC)-aided localization in millimeter wave networks. In particular, a convolutional autoencoder model is proposed to estimate the three-dimensional location of wireless user equipment (UE), based on multipath channel state information (CSI), received by different base stations. In order to learn the radio-geometry map and capture the relative position of each UE, an autoencoder-based channel chart is constructed in an unsupervised manner, such that neighboring UEs in the physical space will remain close in the channel chart. Next, the channel charting model is extended to a semi-supervised framework, where the autoencoder is divided into two components: an encoder and a decoder, and each component is optimized individually, using the labeled CSI dataset with associated location information, to further improve positioning accuracy. Simulation results show that the proposed CC-aided semi-supervised localization yields a higher accuracy, compared with existing supervised positioning and conventional unsupervised CC approaches.\",\n \"Title: Gaussian process regression-based learning rate optimization in convolutional neural networks for medical images classification\\nYear: 2021\\n\\nAbstract: •Propose two novel learning rate optimization algorithms for a popular optimizer.•Apply the Gaussian Process Regression method to predict the classification accuracy.•Obtain a robust learning rate updating rule during the classification process.•Study new medical images that map the lipids and proteins without destroying tissue.•Demonstrate the superiority of the proposed algorithms for classification.\",\n \"Title: Discovering Properties about Arrays via Path Dependence Analysis\\nYear: 2021\\n\\nAbstract: Array, as a fundamental data structure, is widely used in programs. Automated reasoning about arrays needs to discover properties about ranges of elements at certain program points. Such properties are formally specified by universally quantified formulas. A universally quantified formula usually includes two parts: the index range and the properties of the corresponding array elements. In this pa...\",\n \"Title: Detecting Abnormal Social Network Accounts With Hurst Of Interest Distribution\\nYear: 2021\\n\\nAbstract: With the rapid development of the Internet since the beginning of the 21st century, social networks have provided a significant amount of convenience for work, study, and entertainment. Specifically, because of the irreplaceable superiority of social platforms in disseminating information, criminals have thus updated the main methods of social engineering attacks. Detecting abnormal accounts on social networks in a timely manner can effectively prevent the occurrence of malicious Internet events. Different from previous research work, in this work, a method of anomaly detection called Hurst of Interest Distribution is proposed based on the stability of user interest quantifiable from the content of users' tweets, so as to detect abnormal accounts. In detail, the Latent Dirichlet Allocation model is adopted to classify blog content on Twitter into topics to calculate and obtain the topic distribution of tweets sent by a single user within a period of time. Then, the stability degree of the user's tweet topic preference is calculated according to the Hurst index to determine whether the account is compromised. Through experiments, the Hurst indexes of normal and abnormal accounts are found to be significantly different, and the detection rate of abnormal accounts using the proposed method can reach up to 97.93%.\",\n \"Title: Novel stability conditions of linear time-varying impulsive positive systems based on indefinite Lyapunov functions *\\nYear: 2021\\n\\nAbstract: This paper investigates the global asymptotic stability of linear time-varying impulsive positive systems (IPSs). Several novel stability criteria of linear time-varying IPSs with different types of impulsive effects are proposed by constructing an indefinite time-varying copositive Lyapunov function. In particular, by using the maximum and average dwell time methods, we discuss the stability of t...\",\n \"Title: On moment exponential stability of Markovian switching integral delay systems\\nYear: 2021\\n\\nAbstract: This paper studies the moment exponential stability analysis of a class of Markovian switching integral delay systems (MSIDSs). The existence, uniqueness and stability of the solution are discussed firstly. Secondly, by selecting appropriate Lyapunov-Krasovskii (L-K) functionals, delay-dependent sufficient conditions are given such that the general form of MSIDSs and the special form of MSIDSs having multiple delays are mean square exponentially stable respectively. The results are then generalized to robust stability of MSIDSs having multiple delays with uncertain parameters. Finally, numerical examples are given to illustrate the effectiveness of the proposed theoretical results.\",\n \"Title: Experimental Investigation and Fault Diagnosis for Buckled Wet Clutch Based on Multi-Speed Hilbert Spectrum Entropy\\nYear: 2021\\n\\nAbstract: The multi-disc wet clutch is widely used in transmission systems as it transfers the torque and power between the gearbox and the driving engine. During service, the buckling of the friction components in the wet clutch is inevitable, which can shorten the lifetime of the wet clutch and decrease the vehicle performance. Therefore, fault diagnosis and online monitoring are required to identify the buckling state of the friction components. However, unlike in other rotating machinery, the time-domain features of the vibration signal lack efficiency in fault diagnosis for the wet clutch. This paper aims to present a new fault diagnosis method based on multi-speed Hilbert spectrum entropy to classify the buckling state of the wet clutch. Firstly, the wet clutch is classified depending on the buckling degree of the disks, and then a bench test is conducted to obtain vibration signals of each class at varying speeds. By comparing the accuracy of different classifiers with and without entropy, Hilbert spectrum entropy shows higher efficiency than time-domain features for the wet clutch diagnosis. Thus, the classification results based on multi-speed entropy achieve even better accuracy.\",\n \"Title: KGAT-SR: Knowledge-Enhanced Graph Attention Network for Session-based Recommendation\\nYear: 2021\\n\\nAbstract: As a main task of session-based recommendation, next interaction (item) recommendation aims to recommend the next possible interaction (e.g., click on a song) given a session context (i.e., a list of happened interactions). This task faces the challenge of how to generate accurate recommendations when only the intra-session dependencies are available. Existing recommendation models usually fail to exploit the knowledge about items to model intra-session dependencies. Therefore, this paper addresses the problem of next item recommendation given a session context of an ordered, single-type-action, and anonymous session, and investigates how to effectively model intra-session dependencies by leveraging the knowledge from a knowledge graph (KG). We propose a novel model called Knowledge-enhanced Graph Attention Network for Session-based Recommendation (KGAT-SR). Its core idea is that the knowledge about items from a KG is exploited via knowledge graph attention network to generate a knowledge enhanced session graph (KESG). After the KESG is aggregated via weighted graph attention, the node features and graph topology in the graph are utilized to generate accurate session embedding, which can be used to recommend the next item. Experiments show that KGAT-SR significantly outperforms the state-of-the-art models for next item recommendation. KGAT-SR's source code is available at https://github.com/hudske/KGAT-SR.\",\n \"Title: Leaving No One Behind: A Multi-Scenario Multi-Task Meta Learning Approach for Advertiser Modeling\\nYear: 2022\\n\\nAbstract: ABSTRACTAdvertisers play an essential role in many e-commerce platforms like Taobao and Amazon. Fulfilling their marketing needs and supporting their business growth is critical to the long-term prosperity of platform economies. However, compared with extensive studies on user modeling such as click-through rate predictions, much less attention has been drawn to advertisers, especially in terms of understanding their diverse demands and performance. Different from user modeling, advertiser modeling generally involves many kinds of tasks (e.g. predictions of advertisers' expenditure, active-rate, or total impressions of promoted products). In addition, major e-commerce platforms often provide multiple marketing scenarios (e.g. Sponsored Search, Display Ads, Live Streaming Ads) while advertisers' behavior tend to be dispersed among many of them. This raises the necessity of multi-task and multi-scenario consideration in comprehensive advertiser modeling, which faces the following challenges: First, one model per scenario or per task simply doesn't scale; Second, it is particularly hard to model new or minor scenarios with limited data samples; Third, inter-scenario correlations are complicated, and may vary given different tasks. To tackle these challenges, we propose a multi-scenario multi-task meta learning approach (M2M) which simultaneously predicts multiple tasks in multiple advertising scenarios. Specifically, we introduce a novel meta unit that incorporates rich scenario knowledge to learn explicit inter-scenario correlations and can easily scale to new scenarios. Furthermore, we present a meta attention module to capture diverse inter-scenario correlations given different tasks, and a meta tower module to enhance the capability of capturing the representation of scenario-specific features. Compelling results from both offline evaluation and online A/B tests demonstrate the superiority of M2M over state-of-the-art methods.\",\n \"Title: Analysis of the effect of objective function on the performance of the algorithm for the inverse kinematic of manipulator\\nYear: 2021\\n\\nAbstract: In order to analyze the influence of the objective function on the algorithm, we compare the common definitions of objective functions and propose a piecewise objective function definition method based on error value to further improve the algorithm performance. Using classical swarm intelligence optimization algorithms such as DE, MABC, PSO, three types of objective functions are contrast analyze...\",\n \"Title: A Big Data-Driven Approach to Analyze the Influencing Factors of Enterprise's Technological Innovation\\nYear: 2022\\n\\nAbstract: A data-driven intelligent analysis method is proposed in this paper to explore and identify the enterprise's technological innovation influencing factors. Questionnaire surveys or expert interviews are usually adopted by the traditional evaluation methods for indicators of technological innovation selection. However, it inevitably involves human factors and experts' subjective judgments, which may affect the result of enterprises evaluation. The research presents an improved text clustering method based on a semantic concept model to explore and analyze the key influencing factors of enterprise's technological innovation. The study collects textual data from 400 enterprises in Beijing and smart analyzes the critical influencing factors of enterprise's technological innovation by using the proposed method. The influencing factors can be divided into seven categories. In addition, compared with the traditional K-means clustering method, the proposed method has a good effect. We proposed a methodology to conduct an intelligent analysis for enterprise's technological innovation under the data-driven. It can provide more objective and auxiliary suggestions for the evaluation of the enterprise's technology innovation.\",\n \"Title: Mutualistic Mechanism in Symbiotic Radios\\nYear: 2021\\n\\nAbstract: In symbiotic radio (SR), also called cognitive backscatter communications, a secondary transmitter (STx) transmits messages by modulating its information over the RF signals from a primary transmitter (PTx), and in return, the secondary transmission provides multipath gain instead of interference to the primary transmission when the spreading factor K of SR is large enough. In this paper, we are interested in the fundamental mutualistic mechanism between the primary and secondary transmissions in SR, which describes the condition through which the two systems can benefit each other. We first derive the closed-form expressions for the bit error rates (BERs) for both primary and secondary transmissions for general K, then obtain the condition on K to enable mutualistic symbiosis in SR. It is observed that the critical point of K is related to the average strengths of the direct and backscatter links when the number of receiving antennas is large. Extensive simulation and numerical results are provided to verify the accuracy of theoretical analysis and demonstrate the interrelationship between primary and secondary transmissions.\",\n \"Title: Enhancing EFL Learners' English Speaking Performance Through Vlog-Based Digital Multimodal Composing Activities\\nYear: 2021\\n\\nAbstract: Both voice blogs and video blogs have been widely used in various fields, their applications in English as a foreign language (EFL) learning mostly in universities have been mainly to improve students' listening and speaking ability. Relatively few studies have explored how engaging EFL learners in making video blogs might help advance their speaking performance. This study therefore is an investigation of the effects of making voice and video blogs on EFL learners' speaking performance and of their perceptions of vlog-based digital multimodal composing (DMC). Sixty-seven middle school students from Guangdong, China were recruited in this ten-week exploratory study. Data included their pretest and posttest speaking scores, two vlog recordings, questionnaire, and semi-structured interview. The results of this study testified vlog-based DMC's positive influences on speaking performance and indicated that from their first to second vlogs, the students had performed better fluency. Also, video blog-making EFL learners outperformed its counterparts regarding accuracy, while under-performed in fluency in which they demonstrated some significant changes. Pedagogical implications and recommendations for future research are discussed.\",\n \"Title: Bifurcation analysis of an ecological model with nonlinear state-dependent feedback control by Poincare map defined in phase set\\nYear: 2022\\n\\nAbstract: Ecosystems often need to integrate instantaneous interventions such as biological resource management or integrated pest control. The implementation of interventions, in turn, depends on the state and its change rate of the system, which brings great challenges for the stability and bifurcation analyses. To develop qualitative analysis tech-niques, we propose a predator-prey model with state-dependent pulse interventions, including spraying insecticides and releasing natural enemies, in which the implemen-tation of control measures depends on whether the weighted value of pest density and its change rate reaches the action threshold. We first address the threshold condition for the existence and stability of the boundary periodic solutions and then define a one-parameter family of discrete (Poincare) maps. By analyzing the properties of those discrete maps, we conclude that if there is no interior equilibrium for the system without control measures and the releasing amount of natural enemies is greater than zero, then there is at least one positive periodic solution. While if the system without control measures has an internal equilibrium and only the chemical tactic is applied, then there could be an unstable positive periodic solution near the boundary periodic solution. Consequently, backward bifurcation and bi-stability occur. The analytical techniques developed here could be applied to analyze more generalized models and other fields, including infectious disease control. (c) 2021 Elsevier B.V. All rights reserved.\",\n \"Title: Assessing work resumption in hospitals during the COVID-19 epidemic in China using multiscale geographically weighted regression\\nYear: 2022\\n\\nAbstract: The resumption of work and production is one of the key issues during the novel coronavirus (COVID-19) post-epidemic phase. We used location-based service data of mobile devices to assess the work resumption of 22,098 hospitals in mainland China. The multiscale influences of the determinants on work resumption in hospitals, including medical-service capacity, human movement, and epidemic severity, were examined using the multiscale geographically weighted regression technique. This study provides a novel insight into the assessment of work resumption in hospitals and its determinants, and is flexible to be extended to evaluate the work resumption of other industries. The findings can introduce helpful information for other countries to implement the strategies of work recovery during the post-epidemic phase.\",\n \"Title: Traded Control of Human–Machine Systems for Sequential Decision-Making Based on Reinforcement Learning\\nYear: 2022\\n\\nAbstract: Sequential decision-making (SDM) is a common type of decision-making problem with sequential and multistage characteristics. Among them, the learning and updating of policy are the main challenges in solving SDM problems. Unlike previous machine autonomy driven by artificial intelligence alone, we improve the control performance of SDM tasks by combining human intelligence and machine intelligence. Specifically, this article presents a paradigm of a human–machine traded control systems based on reinforcement learning methods to optimize the solution process of sequential decision problems. By designing the idea of autonomous boundary and credibility assessment, we enable humans and machines at the decision-making level of the systems to collaborate more effectively. And the arbitration in the human–machine traded control systems introduces the Bayesian neural network and the dropout mechanism to consider the uncertainty and security constraints. Finally, experiments involving machine traded control, human traded control were implemented. The preliminary experimental results of this article show that our traded control method improves decision-making performance and verifies the effectiveness for SDM problems.\",\n \"Title: The impact of misspecification of nuisance parameters on test for homogeneity in zero-inflated Poisson model: A simulation study\\nYear: 2022\\n\\nAbstract: Most of the existing methodologies for evaluating heterogeneity in zero-inflated Poisson (ZIP) models are often assuming that the Poisson mean is a function of nuisance parameters. However, these nuisance parameters can be misspecified when performing these methodologies, the validity and the power of the test may be affected. In this article, we primarily focus on investigating the impact of misspecification on the performance of score test for homogeneity in ZIP models. Through an intensive simulation study, we find that: 1) under misspecification, the limiting distribution of the score test statistic under the null no longer follows a distribution. A parametric bootstrap methodology is suggested to use to find the true null limiting distribution of the score test statistic; 2) the power of the test decreases as the number of covariates in the Poisson mean increases. The test with a constant Poisson mean has the highest power, even compared to the test with a well-specified mean. At last, simulation results are applied to the Wuhan Inpatient Care Insurance data which contain excess zeros.\",\n \"Title: Surveillance video anomaly detection via non-local U-Net frame prediction\\nYear: 2022\\n\\nAbstract: Anomaly detection of surveillance video has become a critical concern in computer vision. It can be used for real-time monitoring and the timely generation of alarms and is widely applied in transportation systems and security systems. An unsupervised anomaly detection method for surveillance video based on frame prediction is implemented in this paper. Generative Adversarial Network (GAN) is used to generate the high-quality frame. Two generators are designed to predict the next future frame. Non-local U-Net is proposed as Generator 1 for frame prediction to predict the global information. Generator 2 obtains more related past frame features and large contour information. The predicted frame and the ground truth are compared to determine anomalies. We take spatial constraints during generative adversarial training, including gradient loss and intensity loss, and time constraints, such as optical flow loss, into account. We experimentally verify that the proposed method has better accuracy in surveillance videos than some other state-of-the-art anomaly detection algorithms.\",\n \"Title: Secure, Efficient, and Weighted Access Control for Cloud-Assisted Industrial IoT\\nYear: 2022\\n\\nAbstract: In the cloud-assisted Industrial Internet of Things (IIoT), ciphertext-policy attribute-based encryption (CP-ABE) could help the data owner (DO) share his sensitive data via the cloud under self-defined access structures. Among general CP-ABE schemes, the decryption overhead, the key generation cost, and the ciphertext length increase with the number of involved attributes. Additionally, only regular attributes are taking into consideration rather than weighted attributes. In this article, we proposed a secure, efficient, and weighted access control scheme (SEWAC) for cloud-assisted IIoT applications. SEWAC enables the DO to formulate any fine-grained access structure over weighted attributes without making it more complicated. Furthermore, such weighted attributes would not add the length of ciphertext. SEWAC also supports online/offline key generation to alleviate the computational cost of the authority from answering mass key requests in the online phase, while most computational tasks are executed in the offline phase. The heavy decryption overhead is offloaded to the cloud. To ensure the cloud to honestly execute the process of outsourced decryption, we design an efficient batch verification method, which allows the user to spend only three bilinear pairing operations in checking the correctness of batch results. We also give the formal security proof of the proposed scheme. Comprehensive comparisons and implementation results indicate that SEWAC can better achieve weighted access control, compressed ciphertext length, efficient key generation, and the assurance of the outsourced decryption result.\",\n \"Title: Decentralized control for multi-sensors networked systems with different transmission delays and packet dropouts\\nYear: 2022\\n\\nAbstract: In this paper, the linear quadratic (LQ) optimal decentralized control and stabilization problems are investigated for multi-sensors networked control systems (MSNCSs) with multiple controllers of different information structure. Specifically, for a MSNCS, in view of the packet dropouts and the transmission delays, each controller may access different information sets. To begin with, the sufficient and necessary solvability conditions for the LQ decentralized control problems are developed. Consequently, for the purpose of deriving the optimal decentralized control strategy, an innovative orthogonal decomposition method is proposed to decouple the forward and backward stochastic difference equations (FBSDEs) from the maximum principle. In the following, we show that the optimal decentralized controller can be calculated according to a set of Riccati-type equations. Finally, a stabilizing controller is derived for the stabilization problem.\",\n \"Title: Optimized Convolutional Neural Network Recognition for Athletes' Pneumonia Image Based on Attention Mechanism\\nYear: 2022\\n\\nAbstract: After high-intensity exercise, athletes have a greatly increased possibility of pneumonia infection due to the immune function of athletes decreasing. Diseases caused by pulmonary bacterial or viral infections can have serious consequences on the health of athletes in a short period of time, and can even lead to their early retirement. Therefore, early diagnosis is the key to athletes' early recovery from pneumonia. Existing identification methods rely too much on professional medical knowledge, which leads to inefficient diagnosis due to the shortage of medical staff. To solve this problem, this paper presents an optimized convolutional neural network recognition method based on an attention mechanism after image enhancement. For the collected images of athlete pneumonia, we first use contrast boost to adjust the coefficient distribution. Then, the edge coefficient is extracted and enhanced to highlight the edge information, and enhanced images of the athlete lungs are obtained by using the inverse curvelet transformation. Finally, an optimized convolutional neural network with an attention mechanism is used to identify the athlete lung images. A series of experimental results show that, compared with the typical image recognition methods based on DecisionTree and RandomForest, the proposed method has higher recognition accuracy for lung images.\",\n \"Title: Design and motion analysis of double quadrilateral mobile mechanism\\nYear: 2022\\n\\nAbstract: Purpose The purpose of this paper is to propose an overall deformation rolling mechanism based on double four-link mechanism. The double quadrilateral mobile mechanism (DQMM) has two switchable working modes which can be used to traverse different terrains or climb over obstacles. Design/methodology/approach The main body of the DQMM is composed of a double four-link mechanism which sharing a public link and two symmetrical steering platforms which placed at both ends of the four-link mechanism. The steering platforms give the DQMM not only steering ability but also reconnaissance ability which can be achieved by carrying sensors such as cameras on steering platforms. By controlling the deformation of the DQMM, it can switch between two working modes (tracked rolling mode and obstacle-climbing mode) to achieve the functions of rolling and obstacle-climbing. Dynamic simulation model was established to verify the feasibility. Findings Based on the kinematics analysis and simulation results of the DQMM, its moving function is realized by the tracked rolling mode, and the obstacle-climbing mode is used to climb over obstacles in structured terrains such as continuous stairs. The feasibility of the two working modes is verified on a physical prototype. Originality/value The work of this paper is a new exploration of applying \\\"overall closed moving linkages mechanism\\\" to the area of small mobile mechanisms. The adaptability of different terrains and the ability of obstacle-climbing are improved by the combination of multi-modes.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":63,"string":"63"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13352,"string":"13,352"}}},{"rowIdx":13353,"cells":{"question_id":{"kind":"string","value":"Tsong Yueh Chen"},"question":{"kind":"string","value":"Generate an abstract for the title \"Test case selection strategies based on Boolean specifications\" using the following items: Test case selection, Boolean specifications, Literal insertion fault, Literal reference fault, MAX-B strategy."},"answer":{"kind":"string","value":"This paper considers test case selection for programs whose specifications are expressed by Boolean algebra. The approach is to select test cases based on Boolean specifications. Three test case selection strategies are proposed that aim at the detection of the literal insertion fault and the literal reference fault. Although the MAX-B strategy proposed by Weyuker et al. guarantees detection of these types of faults, the proposed strategies are more effective in the sense that the derived test cases form a subset of those selected by the MAX-B strategy. Copyright (C) 2001 John Wiley & Sons, Ltd."},"correct_answer":{"kind":"string","value":"This paper considers test case selection for programs whose specifications are expressed by Boolean algebra. The approach is to select test cases based on Boolean specifications. Three test case selection strategies are proposed that aim at the detection of the literal insertion fault and the literal reference fault. Although the MAX-B strategy proposed by Weyuker et al. guarantees detection of these types of faults, the proposed strategies are more effective in the sense that the derived test cases form a subset of those selected by the MAX-B strategy. Copyright (C) 2001 John Wiley & Sons, Ltd."},"documents":{"kind":"list like","value":["Title: Adaptive Random Testing\nYear: 2004\n\nAbstract: In this paper, we introduce an enhanced form of random testing called Adaptive Random Testing. Adaptive random testing seeks to distribute test cases more evenly within the input space. It is based on the intuition\n that for non-point types of failure patterns, an even spread of test cases is more likely to detect failures using fewer test\n cases than ordinary random testing. Experiments are performed using published programs. Results show that adaptive random\n testing does outperform ordinary random testing significantly (by up to as much as 50%) for the set of programs under study.\n These results are very encouraging, providing evidences that our intuition is likely to be useful in improving the effectiveness\n of random testing.","Title: Good Random Testing\nYear: 2004\n\nAbstract: Software Testing is recognized as an essential part of the Software Development process. Random Testing (RT), the selection of test cases at random from the input domain, is a simple and efficient method of Software Testing. Previous research has indicated that, under certain circumstances, the performance of RT can be improved by enforcing a more even, well-spread distribution of test cases over the input domain. Test cases that contribute to this goal can be considered 'good,' and are more desirable when choosing potential test cases than those that do not contribute. Fuzzy Set Theory enables a calculation of the degree of membership of the set of 'good' test cases for any potential test case, in other words, a calculation of how 'good' the test case is. This paper presents research in the area of improving on the failure finding efficiency of RT using Fuzzy Set Theory. An approach is proposed and evaluated according to simulation results and comparison with other testing methods.","Title: Restricted Random Testing\nYear: 2002\n\nAbstract: This paper presents a novel adaptation of traditional random testing, called Restricted Random Testing (RRT). RRT offers a\n significant improvement over random testing, as measured by the F-measure. This paper describes the ideology behind RRT and\n explains its algorithm. RRT’s performance is examined using several experiments, the results of which are presented and discussed.","Title: Metamorphic Testing: A Simple Approach to Alleviate the Oracle Problem\nYear: 2010\n\nAbstract: The oracle problem is very common in the testing of service-oriented systems. Metamorphic testing has been proposed to alleviate the oracle problem in software testing. This talk aims at presenting the state of the art in metamorphic testing. It summaries what testing techniques have been successfully integrated with metamorphic testing and what application areas metamorphic testing have been applied to successfully alleviate the oracle problem. It will also introduce potential research projects using the metamorphic approach.","Title: Comparison of adaptive random testing and random testing under various testing and debugging scenarios\nYear: 2012\n\nAbstract: Adaptive random testing is an enhancement of random testing. Previous studies on adaptive random testing assumed that once a failure is detected, testing is terminated and debugging is conducted immediately. It has been shown that adaptive random testing normally uses fewer test cases than random testing for detecting the first software failure. However, under many practical situations, testing should not be withheld after the detection of a failure. Thus, it is important to investigate the effectiveness with respect to the detection of multiple failures. In this paper, we compare adaptive random testing and random testing under various scenarios and examine whether adaptive random testing is still able to use fewer test cases than random testing to detect multiple software failures. Our study delivers some interesting results and highlights a number of promising research projects. Copyright © 2011 John Wiley & Sons, Ltd.","Title: Distribution-Aware Mutation Analysis\nYear: 2012\n\nAbstract: Mutation analysis is widely employed to evaluate the effectiveness of various software testing techniques. In most situations, mutation operators are uniformly applied to the original programs, while the faults tend to be clustered in practice. This may result in the inappropriate simulation of faults, and thus cannot deliver the reliable evaluation results. To overcome this, we propose a distribution-aware mutation analysis technique and conducted empirical studies to investigate the impact of the mutation distribution on the effectiveness evaluation of testing techniques. As an illustration, we select the commonly practiced random testing technique and two versions of dynamic random testing techniques and apply them to testing Web services. Results of empirical studies suggest that the mutation distribution significantly affects the evaluation results. This observation further indicates that the effectiveness of testing techniques previously evaluated with the uniform mutation analysis needs further realignments.","Title: Metamorphic Testing and Beyond\nYear: 2003\n\nAbstract: When testing a program, correctly executed test cases are seldom explored further, even though they may carry useful information. Metamorphic testing proposes to generate follow-up test cases to check important properties of the target function. It does not need a human oracle for output prediction and comparison. In this paper, we highlight the basic concepts of metamorphic testing and some interesting extensions in the areas of program testing, proving, and debugging. Future research directions are also proposed.","Title: Normalized restricted random testing\nYear: 2003\n\nAbstract: Restricted Random Testing (RRT) is a new method of testing software that improves upon traditional random testing (RT) techniques. This paper presents new data in support of the efficiency of RRT, and presents a variation of the algorithm, Normalized Restricted Random Testing (NRRT). NRRT permits the tester to have better information about the target exclusion rate (R) of RRT, the main control parameter of the method. We examine the performance of the NRRT and Original RRT (ORRT) methods using simulations and experiments, and offer some guidance for their use in practice.","Title: Metamorphic Testing and Testing with Special Values\nYear: 2004\n\nAbstract: The problem of testing programs without test oracles is well known. A commonly used approach is to use special values in testing but this is often insufficient to ensure program correctness. This paper demonstrates the use of metamorphic testing to uncover faults in programs, which could not be detected by special test values. Metamorphic testing can be used as a complementary test method to special value testing. In this paper, the sine function and a search function are used as examples to demonstrate the usefulness of metamorphic testing. This paper also examines metamorphic relationships and the extent of their usefulness in program testing.","Title: DESSERT: a DividE-and-conquer methodology for identifying categorieS, choiceS, and choicE Relations for Test case generation\nYear: 2012\n\nAbstract: This paper extends the choce relation framework, abbreviated as choc'late, which assists software testers in the application of category/choice methods to testing. choc'late assumes that the tester is able to construct a single choice relation table from the entire specification; this table then forms the basis for test case generation using the associated algorithms. This assumption, however, may not hold true when the specification is complex and contains many specification components. For such a specification, the tester may construct a preliminary choice relation table from each specification component, and then consolidate all the preliminary tables into a final table to be processed by choc'late for test case generation. However, it is often difficult to merge these preliminary tables because such merging may give rise to inconsistencies among choice relations or overlaps among choices. To alleviate this problem, we introduce a DividE-and-conquer methodology for identifying categorieS, choiceS, and choicE Relations for Test case generation, abbreviated as dessert. The theoretical framework and the associated algorithms are discussed. To demonstrate the viability and effectiveness of our methodology, we describe case studies using the specifications of three real-life commercial software systems.","Title: Spectrum-Based Fault Localization: Testing Oracles are No Longer Mandatory\nYear: 2011\n\nAbstract: Spectrum-based Fault Localization (SBFL) is one of the most popular approaches for locating software faults, and has received much attention because of its simplicity and effectiveness. It utilizes the execution result of each test case (failure or pass) and the corresponding coverage information to evaluate the likelihood of each program entity (e.g., a statement or a predicate) being faulty. Different formulas for computing such likelihood have been proposed based on different intuitions. All existing SBFL techniques have assumed the existence of a testing oracle, that is, a mechanism which can determine whether the execution of a test case fails or passes. However, such an assumption does not always hold. Recently, metamorphic testing has been proposed to alleviate the oracle problem. Thus, it is a natural extension to investigate how it can help SBFL techniques to locate faults even without using a testing oracle. Based on the framework of metamorphic testing, we have developed a novel concept of mice as a counterpart of the slice used in the current SBFL techniques. More precisely, in the absence of a testing oracle, we can determine whether an expected characterization of the program is satisfied. The outcomes of dissatisfaction or satisfaction of an expected characterization are then regarded as the counterparts of failed or passed executions, respectively, when a testing oracle exists. Since our approach does not require the existence of a testing oracle, it significantly enhances the applicability of SBFL techniques. Case studies on three popular SBFL techniques (Tarantula, Ochiai and Jaccard) with 9 applications are reported to demonstrate the use of the proposed fault localization technique.","Title: An upper bound on software testing effectiveness\nYear: 2008\n\nAbstract: Failure patterns describe typical ways in which inputs revealing program failure are distributed across the input domain—in many cases, clustered together in contiguous regions. Based on these observations several debug testing methods have been developed. We examine the upper bound of debug testing effectiveness improvements possible through making assumptions about the shape, size and orientation of failure patterns. We consider the bounds for testing strategies with respect to minimizing the F-measure, maximizing the P-measure, and maximizing the E-measure. Surprisingly, we find that the empirically measured effectiveness of some existing methods that are not based on these assumptions is close to the theoretical upper bound of these strategies. The assumptions made to obtain the upper bound, and its further implications, are also examined.","Title: Adaptive Random Testing by Exclusion through Test Profile\nYear: 2010\n\nAbstract: One major objective of software testing is to reveal software failures such that program bugs can be removed. Random testing is a basic and simple software testing technique, but its failure-detection effectiveness is often controversial. Based on the common observation that program inputs causing software failures tend to cluster into contiguous regions, some researchers have proposed that an even spread of test cases should enhance the failure-detection effectiveness of random testing. Adaptive random testing refers to a family of algorithms to evenly spread random test cases based on various notions. Restricted random testing, an algorithm to implement adaptive random testing by the notion of exclusion, defines an exclusion region around each previously executed test case, and selects test cases only from outside all exclusion regions. Although having a high failure-detection effectiveness, restricted random testing has a very high computation overhead, and it rigidly discards all test cases inside any exclusion region, some of which may reveal software failures. In this paper, we propose a new method to implement adaptive random testing by exclusion, where test cases are simply selected based on a well-designed test profile. The new method has a low computation overhead and it does not omit any possible program inputs that can detect failures. Our experimental results show that the new method not only spreads test cases more evenly but also brings a higher failure-detection effectiveness than random testing.","Title: A New Method for Constructing Metamorphic Relations\nYear: 2012\n\nAbstract: A fundamental problem for software testing is the oracle problem, which means that in many practical situations, it is extremely expensive, if not impossible, to verify the test result given any possible program input. Metamorphic testing is an approach to alleviating the oracle problem. The key part of metamorphic testing is a set of necessary properties of the software under test, namely metamorphic relations. Metamorphic relations not only help generate test cases, but also provide a mechanism to partially verify the test results without the need of oracle. In most previous studies, metamorphic relations were identified manually by testers in an ad hoc way. There is no systematic methodology that helps us identify metamorphic relations. In this paper, we propose a simple method, namely, the composition of metamorphic relations, for systematically constructing new metamorphic relations based on the already identified metamorphic relations. We conduct a case study and show that new metamorphic relations can be easily constructed by compositing some existing metamorphic relations. It is also observed that the new metamorphic relations are very likely to deliver a higher cost-effectiveness of metamorphic testing than the original metamorphic relations.","Title: Adaptive Random Test Case Generation for Combinatorial Testing\nYear: 2012\n\nAbstract: Random testing (RT), a fundamental software testing technique, has been widely used in practice. Adaptive random testing (ART), an enhancement of RT, performs better than original RT in terms of fault detection capability. However, not much work has been done on effectiveness analysis of ART in the combinatorial test spaces. In this paper, we propose a novel family of ART-based algorithms for generating combinatorial test suites, mainly based on fixed-size-candidate-set ART and restricted random testing (that is, ART by exclusion). We use an empirical approach to compare the effectiveness of test sets obtained by our proposed methods and random selection strategy. Experimental data demonstrate that the ART-based tests cover all possible combinations at a given strength more quickly than randomly chosen tests, and often detect more failures earlier and with fewer test cases in simulations.","Title: An Analysis of Failure-Based Test Profiles for Random Testing\nYear: 2011\n\nAbstract: In random testing, the distribution of the generated test cases is known as the test profile. We consider the effects of different test profiles, taking advantage of probabilistic information about likely failure-revealing inputs, on the effectiveness of random testing for debugging. We examine a failure-proportional testing strategy, in which tests are randomly sampled with replacement, with probability proportional to a previously identified failure probability distribution, compared to a uniform testing strategy, in which tests are randomly sampled uniformly from the entire input domain. We show that neither strategy optimises failure-detection capabilities, and show an alternative strategy that does. We also consider selection without replacement, and examine the robustness of some strategies given a divergence between the estimated and actual failure probability distributions.","Title: Incremental Identification of Categories and Choices for Test Case Generation: A Study of the Software Practitioners' Preferences\nYear: 2013\n\nAbstract: Test case generation is a vital procedure in the engineering of test harnesses. In particular, the choice relation framework and the category-partition method play an important role, by requiring software testers to identify categories (intuitively equivalent to input parameters or environment conditions) and choices (intuitively equivalent to ranges of values) from a specification and to systematically work on the identified choices to generate test cases. Other specification-based test case generation methods (such as the classification-tree method, cause-effect graphing, and combinatorial testing) also have similar requirements, although different terminology such as classifications and classes is used in place of categories and choices. For a large and complex specification that contains many specification components, categories and choices may be identified separately from various kinds of components. We call this practice an incremental identification approach. In this paper, we discuss our study involving 16 experienced software practitioners and three commercial specifications. Our objectives are to determine, from the opinions of the practitioners, (a) the popularity of an incremental identification approach, (b) the usefulness of identifying categories and choices from various kinds of specification components, and (c) possible ways to improve the effectiveness of the identification process.","Title: Application of a Failure Driven Test Profile in Random Testing\nYear: 2009\n\nAbstract: Random testing techniques have been extensively used in reliability assessment, as well as in debug testing. When used to assess software reliability, random testing selects test cases based on an operational profile; while in the context of debug testing, random testing often uses a uniform distribution. However, generally neither an operational profile nor a uniform distribution is chosen from t...","Title: Adaptive random testing based on distribution metrics\nYear: 2009\n\nAbstract: Random testing (RT) is a fundamental software testing technique. Adaptive random testing (ART), an enhancement of RT, generally uses fewer test cases than RT to detect the first failure. ART generates test cases in a random manner, together with additional test case selection criteria to enforce that the executed test cases are evenly spread over the input domain. Some studies have been conducted to measure how evenly an ART algorithm can spread its test cases with respect to some distribution metrics. These studies observed that there exists a correlation between the failure detection capability and the evenness of test case distribution. Inspired by this observation, we aim to study whether failure detection capability of ART can be enhanced by using distribution metrics as criteria for the test case selection process. Our simulations and empirical results show that the newly proposed algorithms not only improve the evenness of test case distribution, but also enhance the failure detection capability of ART.","Title: Adaptive random testing through iterative partitioning revisited\nYear: 2006\n\nAbstract: Recently, Adaptive Random Testing through Iterative Partitioning (IP-ART) has been proposed as a random testing method that is more effective than pure Random Testing. Besides this, it is supposed to be equally effective as very good random testing techniques, namely Distance-Based Adaptive Random Testing and Restricted Random Testing, while only having between linear and quadratic runtime. In the present paper, it is investigated what influence the ratio of width and height of a rectangular input domain has on the effectiveness of various Adaptive Random Testing methods. Based on our findings, an improved version of IP-ART is proposed. The effectiveness of the new method is also analyzed for various ratios of width and height of the input domain.","Title: Restricted Random Testing: Adaptive Random Testing By Exclusion\nYear: 2006\n\nAbstract: Restricted Random Testing (RRT) is a new method of testing software that improves upon traditional Random Testing (RT) techniques. Research has indicated that failure patterns (portions of an input domain which, when executed, cause the program to fail or reveal an error) can influence the effectiveness of testing strategies. For certain types of failure patterns, it has been found that a widespread and even distribution of test cases in the input domain can be significantly more effective at detecting failure compared with ordinary RT. Testing methods based on RT, but which aim to achieve even and widespread distributions, have been called Adaptive Random Testing (ART) strategies. One implementation of ART is RRT. RRT uses exclusion zones around executed, but non-failure-causing, test cases to restrict the regions of the input domain from which subsequent test cases may be drawn. In this paper, we introduce the motivation behind RRT, explain the algorithm and detail some empirical analyses carried out to examine the effectiveness of the method. Two versions of RRT are presented: Ordinary RRT (ORRT) and Normalized RRT (NRRT). The two versions share the same fundamental algorithm, but differ in their treatment of non-homogeneous input domains. Investigations into the use of alternative exclusion shapes are outlined, and a simple technique for reducing the computational overheads of RRT, prompted by the alternative exclusion shape investigations, is also explained. The performance of RRT is compared with RT and another ART method based on maximized minimum test case separation (DART), showing excellent improvement over RT and a very favorable comparison with DART.","Title: An Innovative Approach to Randomising Quasi-random Sequences and Its Application into Software Testing\nYear: 2009\n\nAbstract: Quasi-random sequences, which can evenly spread points across a hypercube, have been widely used in various areas. Recently, quasi-random testing technique, which makes use of quasi-random sequences to generate test cases, was proposed, and it normally has a higher failure-detection capability than pure random testing. However, there exist only a few distinct quasi-random sequences in the literature, and all these sequences are deterministic rather than random. Therefore, the applicability of quasi-random sequences in testing is restricted. In this paper, we propose a new approach to randomising quasi-random sequences. Out approach can generate many distinct randomised quasi-random sequences that have even distributions of points. The experimental results also show that these sequences can significantly enhance the effectiveness of random testing.","Title: A New Perspective of the Proportional Sampling Strategy\nYear: 1999\n\nAbstract: To compare the performance of different testing strategies, P-measure and E-measure are two effectiveness measures used in previous analytical studies. P-measure, which is defined as the probability of detecting at least one failure, is a measure of how likely it is that failure-causing inputs are selected at least once as test cases. E-measure, which is defined as the expected number of failures ...","Title: On the statistical properties of testing effectiveness measures\nYear: 2006\n\nAbstract: We examine the statistical variability of three commonly used software testing effectiveness measures-the E-measure (expected number of failures detected), P-measure (probability of detecting at least one failure), and F-measure (number of tests required to detect the first failure). We show that for random testing with replacement, the F-measure will be distributed according to the geometric distribution. A simulation study examines the distribution of two adaptive random testing methods, to investigate how closely their sampling distributions approximate the geometric distribution. One key observation is that in the worst case scenario, the sampling distribution of adaptive random testing is very similar to that of random testing. The E-measure and P-measure have a normal sampling distribution, but high variability, meaning that large sample sizes are required to obtain results with satisfactorily narrow confidence intervals. We illustrate this with a simulation study for the P-measure. Our results have reinforced, from a perspective other than empirical analysis, that adaptive random testing is a more effective alternative to random testing, with reference to the F-measure. We consider the implications of our findings for previous studies conducted in the area, and make recommendations to future studies.","Title: On the statistical properties of the F-measure\nYear: 2004\n\nAbstract: The F-measure - the number of distinct test cases to detect the first program failure - is an effectiveness measure for debug testing strategies. We show that for random testing with replacement, the F-measure is distributed according to the geometric distribution. A simulation study examines the distribution of two adaptive random testing methods, to study how closely their sampling distributions approximate the geometric distribution, revealing that in the worst case scenario, the sampling distribution for adaptive random testing is very similar to random testing. Our results have provided an answer to a conjecture that adaptive random testing is always a more effective alternative to random testing, with reference to the F-measure. We consider the implications of our findings for previous studies conducted in the area, and make recommendations to future studies.","Title: On the maximin algorithms for test allocations in partition testing\nYear: 2001\n\nAbstract: The proportional sampling (PS) strategy is a partition testing strategy that has been proved to have a better chance than random testing to detect at least one failure. A near proportional sampling (NPS) strategy is one that approximates the PS strategy when the latter is not feasible. We have earlier proved that the (basic) maximin algorithm generates a maximin test allocation, that is, an allocation of test cases that will maximally improve the lower bound performance of the partition testing strategy, and shown that the algorithm may serve as a systematic means of approximating the PS strategy. In this paper, we derive the uniqueness and completeness conditions of generating maximin test allocations, propose the complete maximin algorithm that generates all possible maximin test allocations and demonstrate empirically that the new algorithm is consistently better than random testing as well as several other NPS strategies.","Title: Testing an Open Source Suite for Open Queuing Network Modelling Using Metamorphic Testing Technique\nYear: 2009\n\nAbstract: Queuing network modelling is a modelling technique for capacity planning studies of computer and communication systems. Due to complexity of the technique, it is very difficult to know from the computed outputs whether the computation of the modelling software is correct. It is necessary to have an effective testing technique to address this problem. Recently, it has been noticed that metamorphic testing is an effective technique for this kind of problem. In this paper, we study the technique of metamorphic testing in testing queuing network modelling through a set of testing experiments in the Java Modelling Tool – a popular open source queuing network modelling suite.","Title: On Favourable Conditions For Adaptive Random Testing\nYear: 2007\n\nAbstract: Recently, adaptive random testing ( ART) has been developed to enhance the fault-detection effectiveness of random testing (RT). It has been known in general that the fault-detection effectiveness of ART depends on the distribution of failure-causing inputs, yet this understanding is in coarse terms without precise details. In this paper, we conduct an in-depth investigation into the factors related to the distribution of failure-causing inputs that have an impact on the fault-detection effectiveness of ART. This paper gives a comprehensive analysis of the favourable conditions for ART. Our study contributes to the knowledge of ART and provides useful information for testers to decide when it is more cost-effective to use ART.","Title: On the Minimal Essential Subsets and Minimal Representative Sets\nYear: 2000\n\nAbstract: Test suite reduction aims at generating representative sets defined as subsets of a test suite that satisfy the same test\n objective. There are various types of representative sets. Those representative sets without redundancy are referred to as\n the minimal representative sets. A subset of the test suite is referred to as essential if the remaining test cases cannot\n collectively satisfy the same test objective when the subset is removed from the test suite. This paper studies the relationships\n between the set of minimal representative sets and the set of essential subsets.","Title: Backward-Slice-Based Statistical Fault Localization without Test Oracles\nYear: 2013\n\nAbstract: A recent promising technique for fault localization, Backward-Slice-based Statistical Fault Localization (BSSFL), statistically analyzes the backward slices and results of a set of test cases to evaluate the suspiciousness of a statement being faulty. However, BSSFL like many existing fault localization approaches assumes the existence of a test oracle to determine whether the result of a test case is a failure or pass. In reality, test oracles do not always exist, and therefore in such cases BSSFL can be severely infeasible. Among current research, metamorphic testing has been widely studied as a technique to alleviate the oracle problem. Hence, we leverage metamorphic testing to conduct BSSFL without test oracles. With metamorphic testing, our approach uses the backward slices and the metamorphic result of violation or non-violation for a metamorphic test group, rather than the backward slice and the result of failure or pass for an individual test case in BSSFL. Because our approach does not need the execution result of a test case, it implies that BSSFL can be extended to those application domains where no test oracle exists. The experimental results on 8 programs and 2 groups of the maximal suspiciousness evaluation formulas show that our proposed approach demonstrates the effectiveness comparable to that of existing BSSFL techniques in the cases where test oracles exist.","Title: Test Suite Reduction and Fault Detecting Effectiveness: An Empirical Evaluation\nYear: 2001\n\nAbstract: Test suite reduction is aimed at finding representative sets that can satisfy the same testing objective as their original test suite. As a subset of the original test suite, the representative set may have less fault detection capability. However, researches show that a representative set and its original test suite have similar fault detection capabilities for the case of coverage based criteria. This paper investigates the relationship between the fault detection capabilities of a representative set and its original test suite when the generation of the test suite is based on some fault-based test case selection criteria.","Title: Integration Testing Of Context-Sensitive Middleware-Based Applications: A Metamorphic Approach\nYear: 2006\n\nAbstract: During the testing of context-sensitive middleware-based software, the middleware checks the current situation to invoke the appropriate functions of the applications. Since the middleware remains active and the situation may continue to evolve, however, the conclusion of some test cases may not easily be identified. Moreover, failures appearing in one situation may be superseded by subsequent correct outcomes and, therefore, be hidden.We alleviate the above problems by making use of a special kind of situation, which we call checkpoints, such that the middleware will not activate the functions under test. We recommend testers to generate test cases that start at a checkpoint and end at another. Testers may identify relations that associate different execution sequences of a test case. They then check the results of each test case to detect any contravention of such relations. We illustrate our technique with an example that shows how hidden failures can be detected. We also report the experimentation carried out on an RFID-based location-sensing application on top of a context-sensitive middleware.","Title: Code Coverage of Adaptive Random Testing\nYear: 2013\n\nAbstract: Random testing is a basic software testing technique that can be used to assess the software reliability as well as to detect software failures. Adaptive random testing has been proposed to enhance the failure-detection capability of random testing. Previous studies have shown that adaptive random testing can use fewer test cases than random testing to detect the first software failure. In this paper, we evaluate and compare the performance of adaptive random testing and random testing from another perspective, that of code coverage. As shown in various investigations, a higher code coverage not only brings a higher failure-detection capability, but also improves the effectiveness of software reliability estimation. We conduct a series of experiments based on two categories of code coverage criteria: structure-based coverage, and fault-based coverage. Adaptive random testing can achieve higher code coverage than random testing with the same number of test cases. Our experimental results imply that, in addition to having a better failure-detection capability than random testing, adaptive random testing also delivers a higher effectiveness in assessing software reliability, and a higher confidence in the reliability of the software under test even when no failure is detected.","Title: Does Adaptive Random Testing Deliver a Higher Confidence than Random Testing?\nYear: 2008\n\nAbstract: Random testing (RT) is a fundamental software testing technique. Motivated by the rationale that neighbouring test cases tend to cause similar execution behaviours, adaptive random testing (ART) was proposed as an enhancement of RT, which enforces random test cases evenly spread over the input domain. ART has always been compared with RT from the perspective of the failure-detection capability. Previous studies have shown that ART can use fewer test cases to detect the first software failure than RT. In this paper, we aim to compare ART and RT from the perspective of program-based coverage. Our experimental results show that given the same number of test cases, ART normally has a higher percentage of coverage than RT. In conclusion, ART outperforms RT not only in terms of the failure-detection capability, but also in terms of the thoroughness of program-based coverage. Therefore, ART delivers a higher confidence of the software under test than RT even when no failure has been revealed.","Title: The ART of Divide and Conquer: An Innovative Approach to Improving the Efficiency of Adaptive Random Testing\nYear: 2013\n\nAbstract: Test case selection is a prime process in the engineering of test harnesses. In particular, test case diversity is an important concept. In order to achieve an even spread of test cases across the input domain, Adaptive Random Testing (ART) was proposed such that the history of previously executed test cases are taken into consideration when selecting the next test case. This was achieved through various means such as best candidate selection, exclusion, partitioning, and diversity metrics. Empirical studies showed that ART algorithms make good use of the concept of even spreading and achieve 40 to 50% improvement in test effectiveness over random testing in revealing the first failure, which is close to the theoretical limit. However, the computational complexity of ART algorithms may be quadratic or higher, and hence efficiency is an issue when a large number of previously executed test cases are involved. This paper proposes an innovative divide-and-conquer approach to improve the efficiency of ART algorithms while maintaining their performance in effectiveness. Simulation studies have been conducted to gauge its efficiency against two most commonly used ART algorithms, namely, fixed size candidate set and restricted random testing. Initial experimental results show that the divide-and-conquer technique can provide much better efficiency while maintaining similar, or even better, effectiveness.","Title: How Effectively Does Metamorphic Testing Alleviate the Oracle Problem?\nYear: 2014\n\nAbstract: In software testing, something which can verify the correctness of test case execution results is called an oracle. The oracle problem occurs when either an oracle does not exist, or exists but is too expensive to be used. Metamorphic testing is a testing approach which uses metamorphic relations, properties of the software under test represented in the form of relations among inputs and outputs of multiple executions, to help verify the correctness of a program. This paper presents new empirical evidence to support this approach, which has been used to alleviate the oracle problem in various applications and to enhance several software analysis and testing techniques. It has been observed that identification of a sufficient number of appropriate metamorphic relations for testing, even by inexperienced testers, was possible with a very small amount of training. Furthermore, the cost-effectiveness of the approach could be enhanced through the use of more diverse metamorphic relations. The empirical studies presented in this paper clearly show that a small number of diverse metamorphic relations, even those identified in an ad hoc manner, had a similar fault-detection capability to a test oracle, and could thus effectively help alleviate the oracle problem.","Title: On the fixpoints of nondeterministic recursive definitions\nYear: 1984\n\nAbstract: This paper is concerned with the existence and properties of various fixpoints of nondeterministic recursive definitions.","Title: On the expected number of failures detected by subdomain testing and random testing\nYear: 1996\n\nAbstract: We investigate the efficacy of subdomain testing and random testing using the expected number of failures detected (the E-measure) as a measure of effectiveness. Simple as it is, the E-measure does provide a great deal of useful information about the fault detecting capability of testing strategies. With the E-measure, we obtain new characterizations of subdomain testing, including several new conditions that determine whether subdomain testing is more or less effective than random testing. Previously, the efficacy of subdomain testing strategies has been analyzed using the probability of detecting at least one failure (the P-measure) for the special case of disjoint subdomains only. On the contrary, our analysis makes use of the E-measure and considers also the general case in which subdomains may or may not overlap. Furthermore, we discover important relations between the two different measures. From these relations, we also derive corresponding characterizations of subdomain testing in terms of the P-measure","Title: On the Correlation between the Effectiveness of Metamorphic Relations and Dissimilarities of Test Case Executions\nYear: 2013\n\nAbstract: Metamorphic testing (MT) is a property-based automated software testing method. It alleviates the oracle problem by testing programs against metamorphic relations (MRs), which are necessary properties among multiple executions of the target program. For a given problem, usually more than one MR can be identified. It is therefore of practical importance for testers to know the nature of good MRs, that is, which MRs are likely to have higher chances of revealing failures. To address this issue we investigate the correlation between the fault-detection effectiveness of MRs and the dissimilarity (distance) of test case execution profiles. Empirical study results reveal that there is a strong and statistically significant positive correlation between the fault-detection effectiveness and the distance. The findings of this research can help to develop automated means of selecting/prioritizing MRs for cost-effective metamorphic testing.","Title: On the structural properties of the set of fixpoints for nondeterministic recursive definitions\nYear: 1996\n\nAbstract: In this paper, we investigate the structural properties of the set of fixpoints for the class of nondeterministic recursive definitions. Our study reveals close resemblance between the structural properties of the set of fixpoints and those of the set of prefixpoints, and it establishes some equality relationships between various fixpoints and their corresponding prefixpoints. Also observed are some nonequality relationships between various fixpoints and their corresponding postfixpoints.","Title: How well does test case prioritization integrate with statistical fault localization?\nYear: 2012\n\nAbstract: Context: Effective test case prioritization shortens the time to detect failures, and yet the use of fewer test cases may compromise the effectiveness of subsequent fault localization. Objective: The paper aims at finding whether several previously identified effectiveness factors of test case prioritization techniques, namely strategy, coverage granularity, and time cost, have observable consequences on the effectiveness of statistical fault localization techniques. Method: This paper uses a controlled experiment to examine these factors. The experiment includes 16 test case prioritization techniques and four statistical fault localization techniques using the Siemens suite of programs as well as grep, gzip, sed, and flex as subjects. The experiment studies the effects of the percentage of code examined to locate faults from these benchmark subjects after a given number of failures have been observed. Results: We find that if testers have a budgetary concern on the number of test cases for regression testing, the use of test case prioritization can save up to 40% of test case executions for commit builds without significantly affecting the effectiveness of fault localization. A statistical fault localization technique using a smaller fraction of a prioritized test suite is found to compromise its effectiveness seriously. Despite the presence of some variations, the inclusion of more failed test cases will generally improve the fault localization effectiveness during the integration process. Interestingly, during the variation periods, adding more failed test cases actually deteriorates the fault localization effectiveness. In terms of strategies, Random is found to be the most effective, followed by the ART and Additional strategies, while the Total strategy is the least effective. We do not observe sufficient empirical evidence to conclude that using different coverage granularity levels have different overall effects. Conclusion: The paper empirically identifies that strategy and time-cost of test case prioritization techniques are key factors affecting the effectiveness of statistical fault localization, while coverage granularity is not a significant factor. It also identifies a mid-range deterioration in fault localization effectiveness when adding more test cases to facilitate debugging.","Title: Constraints For Safe Partition Testing Strategies\nYear: 1996\n\nAbstract: Although previous studies have shown that partition testing strategies are not always very effective, with appropriate restrictions on the test allocation they can be guaranteed to be safe, in the sense that they will never be less reliable in detecting at least one failure than random testing, Several sufficient conditions for this have already been established in the literature. In particular, the proportional sampling strategy, which allocates test cases in proportion to the size of the subdomains from which they are selected, has been proved to be safe for all programs. In practice, since the number of test cases must be positive integers, often the proportional sampling strategy can only be approximated. This paper examines the necessary conditions for safe partition testing strategies. We also prove that, when the input domain is large enough with respect to the numbers of failure-causing inputs and test cases, a safe partition testing strategy cannot deviate from the proportional sampling strategy other than rounding due to integral constraints.","Title: A revisit of fault class hierarchies in general boolean specifications\nYear: 2011\n\nAbstract: Recently, Kapoor and Bowen [2007] have extended the works by Kuhn [1999], Tsuchiya and Kikuno [2002], and Lau and Yu [2005]. However, their proofs overlook the possibility that a mutant of the Boolean specifications under test may be equivalent. Hence, each of their fault relationships is either incorrect or has an incorrect proof. In this article, we give counterexamples to the incorrect fault relationships and provide new proofs for the valid fault relationships. Furthermore, a co-stronger fault relation is introduced to establish a new fault class hierarchy for general Boolean specifications.","Title: Metamorphic fault tolerance: an automated and systematic methodology for fault tolerance in the absence of test oracle\nYear: 2014\n\nAbstract: A system may fail due to an internal bug or a fault in its execution environment. Incorporating fault tolerance strategies enables such system to complete its function despite the failure of some of its parts. Prior to the execution of some fault tolerance strategies, failure detection is needed. Detecting incorrect output, for instance, assumes the existence of an oracle to check the correctness of program outputs given an input. However, in many practical situations, oracle does not exist or is extremely difficult to apply. Such an oracle problem is a major challenge in the context of software testing. In this paper, we propose to apply metamorphic testing, a software testing method that alleviates the oracle problem, into fault tolerance. The proposed technique supports failure detection without the need of oracles.","Title: An assessment of systems and software engineering scholars and institutions (2002–2006)\nYear: 2009\n\nAbstract: This paper summarizes a survey of publications in the field of systems and software engineering from 2002 to 2006. The survey is an ongoing, annual event that identifies the top 15 scholars and institutions over a 5-year period. The rankings are calculated based on the number of papers published in TSE, TOSEM, JSS, SPE, EMSE, IST, and Software. The top-ranked institution is Korea Advanced Institute of Science and Technology, Korea, and the top-ranked scholar is Magne Jørgensen of Simula Research Laboratory, Norway.","Title: A decision-theoretic approach to the test allocation problem in partition testing\nYear: 2002\n\nAbstract: A partition testing strategy consists of two components: a partitioning scheme which determines the way in which the program's input domain is partitioned into subdomains; and an allocation of test cases which determines the exact number of test cases selected from each subdomain. This paper investigates the problem of determining the test allocation when a particular partitioning scheme has been chosen. We show that this problem can be formulated as a classic problem of decision-making under uncertainty, and analyze several well known criteria to resolve this kind of problem. We present algorithms that solve the test allocation problem based on these criteria, and evaluate these criteria by means of a simulation experiment. We also discuss the applicability and implications of applying these criteria in the context of partition testing.","Title: A theoretical analysis of the risk evaluation formulas for spectrum-based fault localization\nYear: 2013\n\nAbstract: An important research area of Spectrum-Based Fault Localization (SBFL) is the effectiveness of risk evaluation formulas. Most previous studies have adopted an empirical approach, which can hardly be considered as sufficiently comprehensive because of the huge number of combinations of various factors in SBFL. Though some studies aimed at overcoming the limitations of the empirical approach, none of them has provided a completely satisfactory solution. Therefore, we provide a theoretical investigation on the effectiveness of risk evaluation formulas. We define two types of relations between formulas, namely, equivalent and better. To identify the relations between formulas, we develop an innovative framework for the theoretical investigation. Our framework is based on the concept that the determinant for the effectiveness of a formula is the number of statements with risk values higher than the risk value of the faulty statement. We group all program statements into three disjoint sets with risk values higher than, equal to, and lower than the risk value of the faulty statement, respectively. For different formulas, the sizes of their sets are compared using the notion of subset. We use this framework to identify the maximal formulas which should be the only formulas to be used in SBFL.","Title: Enhancing Adaptive Random Testing through Partitioning by Edge and Centre\nYear: 2007\n\nAbstract: Quality requirements of software systems typically affect large portions of the system, and should be taken into account early in the design process. Patterns have become a mainstream technique to associate frequent quality-related design problems with ...","Title: CDFA: A Testing System for C++\nYear: 1998\n\nAbstract: CDFA is a dynamic data flow analysis system for testing C++ programs. It instruments C++ programs with code that reports actions on data. The instrumented program is executed and monitored for anomalies. To effectively test C++ programs, CDFA incorporates extended actions, extended state transition diagrams, implicit state variables, functional instrumentation and object-based instrumentation.","Title: Conformance Testing of Network Simulators Based on Metamorphic Testing Technique\nYear: 2009\n\nAbstract: Network simulators, which implement network protocols under some simulated conditions, have been widely used to analyze the feasibility of network protocols. Conformance testing of the simulator against the protocol is a very important task in the community of telecommunications. However, many current conformance testing methods face a problem of finding a systematic mechanism to verify the test outputs. This paper proposes to use an innovative testing approach, metamorphic testing (MT), to alleviate such a problem. We select one ad-hoc on-demand distance vector (AODV) simulator for study and test its conformance against the AODV protocol by the MT technique. Through our experiments, we illustrate the applicability of MT in the protocol conformance testing, confirm the reliability of the selected AODV simulator, and demonstrate the cost-effectiveness of MT using the mutation analysis technique.","Title: Testing embedded software by metamorphic testing: A wireless metering system case study\nYear: 2011\n\nAbstract: In this paper, we present our experience of testing wireless embedded software. We used a wireless metering system in operation, and its software as a case study to demonstrate how a property-based testing technique, called metamorphic testing, can be used in detecting software failures of this wireless embedded system. Our study shows that a careful design of test environments and selection of system properties will enable us to trace back the cause of failures and help in fault diagnosis and debugging.","Title: Fault class prioritization in Boolean expressions\nYear: 2012\n\nAbstract: A recent study has classified faults in Boolean expressions into ten classes and has proved that there are five key fault classes, namely CCF, CDF, ORF, ENF and ASF, such that if a test suite can kill all faulty versions of these five core fault classes, if can kill all faulty versions of all fault classes. In order to generate more effective test suites, we should prioritize these five fault classes further, such that test cases with stronger fault detection capability could be generated as early as possible. Such a process is referred to as the fault class prioritization. Based on the observation in the fault class hierarchy, we divide the five fault classes into two groups {CCF, CDF} and {ORF, ENF, ASF}. Two strategies of fault class prioritization are proposed to generate test cases efficiently. We design experiments using TCAS Boolean expressions and some randomly generated Boolean expressions. The experimental results suggest that if we generate test cases for CCF and CDF firstly, the final test suite always have a higher efficiency of killing faults.","Title: Using the Information: Incorporating Positive Feedback Information into the Testing Process\nYear: 2003\n\nAbstract: Software Testing is recognized as an essential part of the Software Development process. Random Testing (RT), the selection of input test cases at random from the input domain, is a simple and efficient method of Software Testing. RT does not however make use of previously executed test case information; in particular, information about non-failure-causing test cases is ignored. Intuitively, use of this positive feedback information can improve the failure-finding efficiency of a testing method. Adaptive Random Testing (ART) makes use of knowledge of general failure pattern types, and information of previously executed test cases, in the selection of new test cases. A failure pattern in a programýs input domain is composed of the regions of failure-causing inputs. Previous research has categorized failure patterns broadly into three types: point; strip; and block, and has identified important implications for the failure- finding efficiency of test methods, depending on the failure pattern type. In particular, it has been found that for non-point type patterns, the efficiency of RT can be improved upon by simple modification of the basic approach: by ensuring a more even and widespread distribution of test cases over the input domain, the number of test cases required to find the first failure (F-measure) can be reduced dramatically. This insight has motivated several Adaptive Random Testing methods, and produced convincing results. This paper introduces some of the research in this area and suggests areas of interest for future work.","Title: Testing and Validating Machine Learning Classifiers by Metamorphic Testing.\nYear: 2011\n\nAbstract: Machine Learning algorithms have provided core functionality to many application domains - such as bioinformatics, computational linguistics, etc. However, it is difficult to detect faults in such applications because often there is no \"test oracle\" to verify the correctness of the computed outputs. To help address the software quality, in this paper we present a technique for testing the implementations of machine learning classification algorithms which support such applications. Our approach is based on the technique \"metamorphic testing\", which has been shown to be effective to alleviate the oracle problem. Also presented include a case study on a real-world machine learning application framework, and a discussion of how programmers implementing machine learning algorithms can avoid the common pitfalls discovered in our study. We also conduct mutation analysis and cross-validation, which reveal that our method has high effectiveness in killing mutants, and that observing expected cross-validation result alone is not sufficiently effective to detect faults in a supervised classification program. The effectiveness of metamorphic testing is further confirmed by the detection of real faults in a popular open-source classification program.","Title: The universal safeness of test allocation strategies for partition testing\nYear: 2000\n\nAbstract: Given a specification, a partition testing strategy is said to be safe for a program if it is not less probable of detecting at least one failure than random testing, and universally safe, if it is safe for every program. The proportional sampling strategy (PSS) has previously been proved to be universally safe. This paper extends previous results by proving that PSS is actually the only universally safe test allocation strategy for partition testing, thereby settling an open problem in the search for universally safe strategies. Despite this, we show that a close approximation to PSS may still be safe for most programs. We also discuss the practical implications of this result. (C) 2000 Elsevier Science Inc. All rights reserved.","Title: Formalization of equivalence of recursively defined functions\nYear: 1978\n\nAbstract: In this paper we use the fixpoint approach in formalizing the equivalence of recursively defined functions within the framework of predicate calculus. The results suggest some general mathematical techniques useful in proving equivalence of recursive programs.","Title: A revisit of adaptive random testing by restriction\nYear: 2004\n\nAbstract: Adaptive random testing is a black box testing method based on the intuition that random testing failure-finding efficiency can be improved upon, in certain situations, by ensuring a more widespread and evenly distributed spread of test cases in the input domain. One way of achieving this distribution is through the use of exclusion zones and restriction, resulting in a method called restricted random testing (RRT). Recent investigations into the RRT method have revealed several interesting and significant insights. A method of reducing the computational overheads of testing methods by partitioning an input domain, and applying the method to only one of the subdomains, mapping the test cases to other subdomains, has recently been introduced. This method, called mirroring, in addition to alleviating computational costs, has some properties which fit nicely with the insights into RRT, offering solutions to some possible shortcomings of RRT. In this paper we discuss the RRT method and additional insights; we explain mirroring; and we detail applications of mirroring to RRT. The mirror RRT method proves to be a very attractive variation of RRT","Title: Isolating Suspiciousness from Spectrum-Based Fault Localization Techniques\nYear: 2010\n\nAbstract: Spectrum-based fault localization (SBFL) is one of the most promising fault localization approaches, which normally uses the failed and passed program spectrum to evaluate the risks for all program entities. However, it does not explicitly distinguish the different degree in definiteness between the information associated with the failed spectrum and the passed spectrum, which may result in an unreliable location of faults. Thus in this paper, we propose a refinement method to improve the accuracy of the predication by SBFL, through eliminating the indefinite information. Our method categorizes all statements into two groups according to their different suspiciousness, and then uses different evaluation schemes for these two groups. In this way, we can reduce the use of the unreliable information in the ranking list, and finally provide a more precise result. Experimental study shows that for some SBFL techniques, our method can significantly improve their performance in some situations, and in other cases, it can still remain the techniques’ original performance.","Title: Teaching an End-User Testing Methodology\nYear: 2010\n\nAbstract: One important focus of software engineering is how to develop quality software. Software testing is the main approach to the software quality assurance. Nowadays, more and more end-users write the program on their own but lack formal trainings on how to test their programs, and hence cannot guarantee the quality of their own software. Metamorphic testing is a simple, automatable, and cost-effective testing methodology. It is particularly suitable for end-users to test their own programs, because it does not demand the user to have great knowledge of software testing but knowledge of the program under development. In this paper, we report our experience in teaching metamorphic testing to various groups of students at Swinburne University of Technology, Melbourne, Australia. Our work not only enhances the teaching of software testing, but also fosters the training of end-user programmers.","Title: Metamorphic Testing: Applications and Integration with Other Methods: Tutorial Synopsis\nYear: 2012\n\nAbstract: In software testing, an oracle refers to a mechanism against which testers can decide whether or not outcomes of test case executions are correct. The oracle problem refers to situations when either an oracle is not available, or it is too expensive to apply. Metamorphic testing has emerged as an effective and efficient approach to alleviating the oracle problem. This article introduces the basic concepts and procedures of metamorphic testing, and gives examples to show its applications, and integration with other methods.","Title: Testing A Software-Based Pid Controller Using Metamorphic Testing\nYear: 2011\n\nAbstract: The Proportional-Integral-Derivative (PID) controller is ubiquitous in industrial and military systems. Almost all PID controllers are now implemented as software in a microcontroller. Control systems are required to have very high reliability, particularly as they are regularly used in safety-critical systems. An effective testing technique is essential to achieve reliable PID controller software. Unlike simple control algorithms, PID controllers are capable of manipulating the process inputs based on the history and rate of change of the signal. It is very difficult to know whether the computation of the software is correct from the computed outputs. Previous research in other areas has shown that metamorphic testing is an effective technique for this kind of problem. In this paper, we examine metamorphic testing in the context of testing an embedded software PID controller based on the free sample code from ATMEL Corporation. We show that metamorphic testing killed all mutants inserted into the controller software, demonstrating the utility of the technique in testing control systems.","Title: Formalization of correctness of recursive definitions\nYear: 1980\n\nAbstract: We use the fixpoint approach to formalize the correctness of recursive definitions within the framework of first-order predicate calculus. Although the least fixpoint semantics is used, our results suggest some general methods of proving the correctness of recursive definitions without knowing their least fixpoints explicitly.","Title: Two test data selection strategies towards testing of Boolean specifications\nYear: 1997\n\nAbstract: Test data selection for software represented as Boolean formulae has not received much attention until the last decade. Most of the approaches are expression driven because generation of test cases is based on the Boolean formulae being tested. The paper discusses test data generation using a fault based approach in the sense that generation of test cases is based on particular types of faults occurring in the Boolean expression. Two special types of faults are considered. Moreover, two strategies of test case selection that guarantee the detection of these two types of faults are proposed.","Title: An orchestrated survey of methodologies for automated software test case generation\nYear: 2013\n\nAbstract: Test case generation is among the most labour-intensive tasks in software testing. It also has a strong impact on the effectiveness and efficiency of software testing. For these reasons, it has been one of the most active research topics in software testing for several decades, resulting in many different approaches and tools. This paper presents an orchestrated survey of the most prominent techniques for automatic generation of software test cases, reviewed in self-standing sections. The techniques presented include: (a) structural testing using symbolic execution, (b) model-based testing, (c) combinatorial testing, (d) random testing and its variant of adaptive random testing, and (e) search-based testing. Each section is contributed by world-renowned active researchers on the technique, and briefly covers the basic ideas underlying the method, the current state of the art, a discussion of the open research problems, and a perspective of the future development of the approach. As a whole, the paper aims at giving an introductory, up-to-date and (relatively) short overview of research in automatic test case generation, while ensuring a comprehensive and authoritative treatment.","Title: Distribution Metric Driven Adaptive Random Testing\nYear: 2007\n\nAbstract: Adaptive random testing (ART) was developed to enhance the failure detection capability of random testing. The basic principle of ART is to enforce random test cases evenly spread inside the input domain. Various distribution metrics have been used to measure different aspects of the evenness of test case distribution. As expected, it has been observed that the failure detection capability of an ART algorithm is related to how evenly test cases are distributed. Motivated by such an observation, we propose a new family of ART algorithms, namely distribution metric driven ART, in which, distribution metrics are key drivers for evenly spreading test cases inside ART. Out study uncovers several interesting results and shows that the new algorithms can spread test cases more evenly, and also have better failure detection capabilities.","Title: Towards Dynamic Random Testing for Web Services\nYear: 2012\n\nAbstract: In recent years, Service Oriented Architecture (SOA) has been increasingly adopted to develop applications in the context of Internet. To develop reliable SOA-based applications, an important issue is how to ensure the quality of Web services. In this paper, we propose a dynamic random testing (DRT) technique for Web services which is an improvement of the widely practiced random testing. We examine key issues when adapting DRT to the context of SOA and develop a prototype for such an adaptation. Empirical studies are reported where DRT is used to test two real-life Web services and mutation analysis is employed to measure the effectiveness. The experimental results show that DRT can save up to 24% test cases in terms of detecting the first seeded fault, and up to 21% test cases in terms of detecting all seeded faults, both with the cases of uniformed mutation analysis and distribution-aware mutation analysis, which refer to faults being seeded in an even or clustered way, respectively. The proposed DRT and the prototype provide an effective approach to testing Web Services.","Title: Automatic Verification Of Optimization Algorithms: A Case Study Of A Quadratic Assignment Problem Solver\nYear: 2011\n\nAbstract: Metamorphic testing is a technique for the verification of software output without a complete testing oracle. Mathematical optimization, implemented in software, is a problem for which verification can often be challenging. In this paper, we apply metamorphic testing to one such optimization problem, the quadratic assignment problem (QAP). From simple observations of the properties of the QAP, we describe how to derive a number of metamorphic relations useful for verifying the correctness of a QAP solver. We then compare the effectiveness of these metamorphic relations, in \"killing\" mutant versions of an exact QAP solver, to a simulated oracle. We show that metamorphic testing can be as effective as the simulated oracle for killing mutants. We examine the relative effectiveness of different metamorphic relations, both singly and in combination, and conclude that combining metamorphic relations can be significantly more effective than using a single relation.","Title: An Integrated Classification-Tree Methodology For Test Case Generation\nYear: 2000\n\nAbstract: This paper describes an integrated methodology for the construction of test cases from functional specifications using the classification-tree method. It is an integration of our extensions to the classification-hierarchy table, the classification tree construction algorithm, and the classification tree restructuring technique. Based on the methodology, a prototype system ADDICT, which stands for AutomateD test Data generation system using the Integrated Classification-Tree method, has been built.","Title: Automatic generation of test cases from Boolean specifications using the MUMCUT strategy\nYear: 2006\n\nAbstract: A recent theoretical study has proved that the MUMCUT testing strategy (1) guarantees to detect seven types of fault in Boolean specifications in irredundant disjunctive normal form, and (2) requires only a subset of the test sets that satisfy the previously proposed MAX-A and MAX-B strategies, which can detect the same types of fault. This paper complements previous work by investigating various methods for the automatic generation of test cases to satisfy the MUMCUT strategy. We evaluate these methods by using several sets of Boolean expressions, including those derived from real airborne software systems. Our results indicate that the greedy CUN and UCN methods are clearly better than others in consistently producing significantly smaller test sets, whose sizes exhibit linear correlation with the length of the Boolean expressions in irredundant disjunctive normal form. This study provides empirical evidences that the MUMCUT strategy is indeed cost-effective for detecting the faults considered in this paper.","Title: On The Online Parameter Estimation Problem In Adaptive Software Testing\nYear: 2008\n\nAbstract: Software cybernetics is an emerging area that explores the interplay between software and control. The controlled Markov chain (CMC) approach to software testing supports the idea of software cybernetics by treating software testing as a control problem, where the software under test serves as a controlled object modeled by a controlled Markov chain and the software testing strategy serves as the corresponding controller. The software under test and the corresponding software testing strategy form a closed-loop feedback control system. The theory of controlled Markov chains is used to design and optimize the testing strategy in accordance with the testing/reliability goal given explicitly and a priori. Adaptive software testing adjusts and improves software testing strategy online by using the testing data collected in the course of software testing. In doing so, the online parameter estimations play a key role. In this paper, we study the effects of genetic algorithm and the gradient method for doing online parameter estimation in adaptive software testing. We find that genetic algorithm is effective and does not require prior knowledge of the software parameters of concern. Although genetic algorithm is computationally intensive, it leads the adaptive software testing strategy to an optimal software testing strategy that is determined by optimizing a given testing goal, such as minimizing the total cost incurred for removing a given number of defects. On the other hand, the gradient method is computationally favorable, but requires appropriate initial values of the software parameters of concern. It may lead, or fail to lead, the adaptive software testing strategy to an optimal software testing strategy, depending on whether the given initial parameter values are appropriate or not. In general, the genetic algorithm should be used instead of the gradient method in adaptive software testing. Simulation results show that adaptive software testing does work and outperforms random testing.","Title: An Automated Tool (Idaf) To Manipulate Interaction Diagrams And Fragmentations For Multi-Agent Systems\nYear: 1999\n\nAbstract: Interaction diagrams are used in multi-agent systems to graphically describe agent computation threads and communications while fragmentations are the algebraic representations of interaction diagrams. The IDAF (Interaction Diagrams And Fragmentations) tool suite has been developed based on the formalism of interaction diagrams and fragmentations. The tool suite consists of ValidatoR, FormatteR, TranslatoR, GrapheR and TesteR. This paper describes the usage of the tool suite and demonstrates it in two different multi-agent systems.","Title: An enhanced flow analysis technique for detecting unreachability faults in concurrent systems\nYear: 2012\n\nAbstract: We present a flow analysis technique for detecting unreachable states and actions in concurrent systems. It is an enhancement of the approach by Cheung and Kramer. Each process of a concurrent system is modeled as a finite state machine, whose states represent process execution states and whose transitions are labeled by actions. We construct dependency sets incrementally and eliminate spurious paths by checking the execution sequences of actions. We prove mathematically that our algorithm can detect more unreachability faults than the well-known Reif/Smolka and Cheung/Kramer algorithms. The algorithm is easy to manage and its complexity is still polynomial to the system size. Case studies on two commonly used communication protocols show that the technique is effective.","Title: Teaching automated test case generation\nYear: 2005\n\nAbstract: Software testing is a major approach to software quality assurance, but it is relatively neglected in universities' computing curricula. For students majoring in computer science or software engineering, several basic testing methods need to be taught. These testing methods generate test cases based on either specifications or program code. When introducing the testing methods based on program code, it is not easy to let the students experience automated test case generation due to the lack of supporting tools and limited teaching hours. In this paper we report our experience in teaching this topic with limited resources. The evaluation result indicates that our teaching method is effective and can also be adopted in other computer science/software engineering subjects where similar constraints exist.","Title: Distributing test cases more evenly in adaptive random testing\nYear: 2008\n\nAbstract: Adaptive random testing (ART) has recently been proposed to enhance the failure-detection capability of random testing. In ART, test cases are not only randomly generated, but also evenly spread over the input domain. Various ART algorithms have been developed to evenly spread test cases in different ways. Previous studies have shown that some ART algorithms prefer to select test cases from the edge part of the input domain rather than from the centre part, that is, inputs do not have equal chance to be selected as test cases. Since we do not know where the failure-causing inputs are prior to testing, it is not desirable for inputs to have different chances of being selected as test cases. Therefore, in this paper, we investigate how to enhance some ART algorithms by offsetting the edge preference, and propose a new family of ART algorithms. A series of simulations have been conducted and it is shown that these new algorithms not only select test cases more evenly, but also have better failure detection capabilities.","Title: On Some Properties of the Optimally Refined Proportional Sampling Strategy\nYear: 1997\n\nAbstract: The optimally refined proportional sampling strategy has been recommended as a better alternative to random testing, when dividing the input domain into equal-sized partitions is easy. This paper investigates some properties of the optimally refined proportional sampling strategy. This investigation provides some useful information on how well the optimally refined proportional sampling strategy o...","Title: Scenario-Oriented Testing for Web Service Compositions Using BPEL\nYear: 2012\n\nAbstract: Applications are increasingly constructed by orchestrating Web services. Ensuring the reliability of such loosely coupled service compositions is a challenging task. In this paper, we propose an automatic scenario-oriented testing approach for service compositions specified by Business Process Execution Language (BPEL). In our approach, an abstract test model (BGM) is first defined to represent the control flows of BPEL specifications, then test scenarios are derived from the BGM with respect to the given coverage criteria, finally test data are generated to drive the execution of resulting test scenarios. A case study is conducted to demonstrate how our approach can be applied to complex real-life service compositions and the experimental results validate the effectiveness of our approach.","Title: Impacts of Test Suite's Class Imbalance on Spectrum-Based Fault Localization Techniques\nYear: 2013\n\nAbstract: Spectrum-based fault localization (SBFL) uses the execution results of test cases to debug. There are two types of SBFL techniques: one using conventional slices, and the other using metamorphic slices. This paper investigates the ratio between non-violated and violated metamorphic test groups of test suites for SBFL techniques using metamorphic slices. We have observed that the higher the ratio of passed metamorphic test groups to failed metamorphic test groups, the less effective the SBFL techniques using metamorphic slices. This observation is consistent with what has been observed in SBFL techniques using conventional slices. Besides, a new real-life fault in schedule2 of Siemens Suite is identified in our experiments.","Title: Metamorphic slice: An application in spectrum-based fault localization\nYear: 2013\n\nAbstract: Context: Because of its simplicity and effectiveness, Spectrum-Based Fault Localization (SBFL) has been one of the popular approaches towards fault localization. It utilizes the execution result of failure or pass, and the corresponding coverage information (such as program slice) to estimate the risk of being faulty for each program entity (such as statement). However, all existing SBFL techniques assume the existence of a test oracle to determine the execution result of a test case. But, it is common that test oracles do not exist, and hence the applicability of SBFL has been severely restricted. Objective: We aim at developing a framework that can extend the application of SBFL to the common situations where test oracles do not exist. Method: Our approach uses a new concept of metamorphic slice resulting from the integration of metamorphic testing and program slicing. In SBFL, instead of using the program slice and the result of failure or pass for an individual test case, a metamorphic slice and the result of violation or non-violation of a metamorphic relation are used. Since we need not know the execution result for an individual test case, the existence of a test oracle is no longer a requirement to apply SBFL. Results: An experimental study involving nine programs and three risk evaluation formulas was conducted. The results show that our proposed solution delivers a performance comparable to the performance observed by existing SBFL techniques for the situations where test oracles exist. Conclusion: With respect to the problem that SBFL is only applicable to programs with test oracles, we propose an innovative solution. Our solution is not only intuitively appealing and conceptually feasible, but also practically effective. Consequently, test oracles are no longer mandatory for SBFL, and hence the applicability of SBFL is significantly extended.","Title: Enhancing adaptive random testing for programs with high dimensional input domains or failure-unrelated parameters\nYear: 2008\n\nAbstract: Adaptive random testing (ART), an enhancement of random testing (RT), aims to both randomly select and evenly spread test cases. Recently, it has been observed that the effectiveness of some ART algorithms may deteriorate as the number of program input parameters (dimensionality) increases. In this article, we analyse various problems of one ART algorithm, namely fixed-sized-candidate-set ART (FSCS-ART), in the high dimensional input domain setting, and study how FSCS-ART can be further enhanced to address these problems. We propose to add a filtering process of inputs into FSCS-ART to achieve a more even-spread of test cases and better failure detection effectiveness in high dimensional space. Our study shows that this solution, termed as FSCS-ART-FE, can improve FSCS-ART not only in the case of high dimensional space, but also in the case of having failure-unrelated parameters. Both cases are common in real life programs. Therefore, we recommend using FSCS-ART-FE instead of FSCS-ART whenever possible. Other ART algorithms may face similar problems as FSCS-ART; hence our study also brings insight into the improvement of other ART algorithms in high dimensional space.","Title: Adaptive Random Testing: The ART of test case diversity\nYear: 2010\n\nAbstract: Random testing is not only a useful testing technique in itself, but also plays a core role in many other testing methods. Hence, any significant improvement to random testing has an impact throughout the software testing community. Recently, Adaptive Random Testing (ART) was proposed as an effective alternative to random testing. This paper presents a synthesis of the most important research results related to ART. In the course of our research and through further reflection, we have realised how the techniques and concepts of ART can be applied in a much broader context, which we present here. We believe such ideas can be applied in a variety of areas of software testing, and even beyond software testing. Amongst these ideas, we particularly note the fundamental role of diversity in test case selection strategies. We hope this paper serves to provoke further discussions and investigations of these ideas.","Title: An effective testing method for end-user programmers\nYear: 2005\n\nAbstract: End-user programmers do not have extensive knowledge of various software testing methodologies used by professional testers. While they are creating the vast majority of software today, errors are pervasive in the programs due to the lack of testing techniques readily adoptable by end-user programmers. In this article we argue that the technique of metamorphic testing is both practical and effective for end-user programmers.","Title: Dividing strategies for the optimization of a test suite\nYear: 1996\n\nAbstract: Use of the divide-and-conquer approach to optimize a test suite does not guarantee that the optimal solutions could be re-constructed from those of the sub-problems. This paper investigates how the re-construction could be achieved with two dividing strategies. Results of a simulation study are also reported.","Title: Error Detection in C++ through Dynamic Data Flow Analysis\nYear: 1997\n\nAbstract: Recently Chen and Low [5] have investigated the feasibility of using dynamic data flow analysis to test C++ programs. They concluded that the conventional state transition diagram and state variables were too primitive to detect errors in C++ programs. They proposed that class information should be included in the definitions of the state transition diagram and state variables. This paper further investigates the types of errors and how such errors could be detected using the technique of dynamic data flow analysis with the incorporation of their proposal.","Title: Formalization of properties of nondeterministic recursive definitions\nYear: 1980\n\nAbstract: This paper is concerned with the relationship between the correctness and equivalence of nondeterministic recursive definitions and the satisfiability or validity of certain first-order formulas. Our results suggest some general mathematical techniques useful in verifying the properties of nondeterministic recursive programs.","Title: Choices, choices: comparing between CHOC'LATE and the classification-tree methodology\nYear: 2012\n\nAbstract: Two popular specification-based test case generation methods are the choice relation framework and the classification-tree methodology. Both of them come with associated tools and have been used in different applications with success. Since both methods are based on the idea of partition testing, they are similar in many aspects. Because of their similarities, software testers often find it difficult to decide which method to be used in a given testing scenario. This paper aims to provide a solution by first contrasting the strengths and weaknesses of both methods, followed by suggesting practical selection guidelines to cater for different testing scenarios.","Title: A Study On A Path-Based Strategy For Selecting Black-Box Generated Test Cases\nYear: 2001\n\nAbstract: Various black-box methods for the generation of test cases have been proposed in the literature. Many of these methods, including the category-partition method and the classification-tree method, follow the approach of partition testing, in which the input domain is partitioned into subdomains according to important aspects of the specification, and test cases are then derived from the subdomains. Though comprehensive in terms of these important aspects, execution of all the test cases so generated may not be feasible under the constraint of tight testing resources. In such circumstances, there is a need to select a smaller subset of test cases from the original test suite for execution. In this paper, we propose the use of white-box information to guide the selection of test cases from the original test suite generated by a black-box testing method. Furthermore, we have developed some techniques and algorithms to facilitate the implementation of our approach, and demonstrated its viability and benefits by means of a case study.","Title: Adaptive random testing through iterative partitioning\nYear: 2006\n\nAbstract: Random testing (RT) is a fundamental and important software testing technique. Based on the observation that failure-causing inputs tend to be clustered together in the input domain, the approach of Adaptive Random Testing (ART) has been proposed to improve the fault-detection capability of RT. ART employs the location information of previously executed test cases to enforce an even spread of random test cases over the entire input domain. There have been several implementations (algorithms) of ART based on different intuitions and principles. Due to the nature of the principles adopted, these implementations have their own advantages and disadvantages. The majority of them require intensive computations to ensure the generation of evenly spread test cases, and hence incur high overhead. In this paper, we propose the notion of iterative partitioning to reduce the amount of the computation while retaining a high fault-detection capability. As a result, the cost effectiveness of ART has been improved.","Title: Adaptive random testing through test profiles\nYear: 2011\n\nAbstract: Random testing (RT), which simply selects test cases at random from the whole input domain, has been widely applied to test software and assess the software reliability. However, it is controversial whether RT is an effective method to detect software failures. Adaptive random testing (ART) is an enhancement of RT in terms of failure-detection effectiveness. Its basic intuition is to evenly spread random test cases all over the input domain. There are various notions to achieve the goal of even spread, and each notion can be implemented by different algorithms. For example, ‘by exclusion’ and ‘by partitioning’ are two different notions to evenly spread test cases. Restricted random testing (RRT) is a typical algorithm for the notion of ‘by exclusion’, whereas the notion of ‘by partitioning’ can be implemented by either the technique of bisection (ART-B) or the technique of random partitioning (ART-RP). In this paper, we propose a generic approach that can be used to implement different notions. In the new approach, test cases are simply selected based on test profiles that are in turn designed according to certain notions. In this study, we design several test profiles for the notions of ‘by exclusion’ and ‘by partitioning’, and then use these profiles to illustrate our new approach. Our experimental results show that compared with the original RRT, ART-B, and ART-RP algorithms, our new approach normally brings at least a higher failure-detection capability or a lower computational overhead. Copyright © 2011 John Wiley & Sons, Ltd. (A preliminary version of this paper was presented at the 10th International Conference on Quality Software (QSIC 2010)).","Title: Application of Metamorphic Testing to Supervised Classifiers.\nYear: 2009\n\nAbstract: Many applications in the field of scientific computing - such as computational biology, computational linguistics, and others - depend on Machine Learning algorithms to provide important core functionality to support solutions in the particular problem domains. However, it is difficult to test such applications because often there is no \"test oracle\" to indicate what the correct output should be for arbitrary input. To help address the quality of such software, in this paper we present a technique for testing the implementations of supervised machine learning classification algorithms on which such scientific computing software depends. Our technique is based on an approach called \"metamorphic testing\", which has been shown to be effective in such cases. More importantly, we demonstrate that our technique not only serves the purpose of verification, but also can be applied in validation. In addition to presenting our technique, we describe a case study we performed on a real-world machine learning application framework, and discuss how programmers implementing machine learning algorithms can avoid the common pitfalls discovered in our study. We also discuss how our findings can be of use to other areas outside scientific computing, as well.","Title: On the Completeness of a Test Suite Reduction Strategy\nYear: 1999\n\nAbstract: The problem of test suite reduction is to find a subset of test cases from the test suite that can still satisfy the same testing objective. Such a subset is referred to as a representative set of the test suite. We use a problem reduction technique, namely the 1-to-1 redundancy dividing strategy, to find the optimal representative sets, which are the representative sets of the smallest size. The ...","Title: A more general sufficient condition for partition testing to be better than random testing\nYear: 1996\n\nAbstract: Partition testing is an approach to program testing in which the input domain of the program is divided into partitions and test cases are selected from each partition. An alternative approach, known as random testing, is to select test cases at random from the entire input domain. Weyuker and Jeng (1991) observed that if all partitions are equal in sizes and the number of test cases selected from each partition is the same, then partition testing has a better chance of detecting at least one failure than random testing. This condition has been generalized by Chen and Yu (1994). They proved that partition testing is better than random testing so long as test cases are selected in proportion to the size of partitions. In this paper, we prove a more general sufficient condition. Partition testing performs better if the sampling rates are higher for partitions with higher failure rates. Some special cases that follow from this result are also considered.","Title: Prioritization Of Combinatorial Test Cases By Incremental Interaction Coverage\nYear: 2013\n\nAbstract: Combinatorial interaction testing is a well-recognized testing method, and has been widely applied in practice, often with the assumption that all test cases in a combinatorial test suite have the same fault detection capability. However, when testing resources are limited, an alternative assumption may be that some test cases are more likely to reveal failure, thus making the order of executing the test cases critical. To improve testing cost-effectiveness, prioritization of combinatorial test cases is employed. The most popular approach is based on interaction coverage, which prioritizes combinatorial test cases by repeatedly choosing an unexecuted test case that covers the largest number of uncovered parameter value combinations of a given strength (level of interaction among parameters). However, this approach suffers from some drawbacks. Based on previous observations that the majority of faults in practical systems can usually be triggered with parameter interactions of small strengths, we propose a new strategy of prioritizing combinatorial test cases by incrementally adjusting the strength values. Experimental results show that our method performs better than the random prioritization technique and the technique of prioritizing combinatorial test suites according to test case generation order, and has better performance than the interaction-coverage-based test prioritization technique in most cases.","Title: An innovative approach for testing bioinformatics programs using metamorphic testing.\nYear: 2009\n\nAbstract: Background: Recent advances in experimental and computational technologies have fueled the development of many sophisticated bioinformatics programs. The correctness of such programs is crucial as incorrectly computed results may lead to wrong biological conclusion or misguide downstream experimentation. Common software testing procedures involve executing the target program with a set of test inputs and then verifying the correctness of the test outputs. However, due to the complexity of many bioinformatics programs, it is often difficult to verify the correctness of the test outputs. Therefore our ability to perform systematic software testing is greatly hindered. Results: We propose to use a novel software testing technique, metamorphic testing (MT), to test a range of bioinformatics programs. Instead of requiring a mechanism to verify whether an individual test output is correct, the MT technique verifies whether a pair of test outputs conform to a set of domain specific properties, called metamorphic relations (MRs), thus greatly increases the number and variety of test cases that can be applied. To demonstrate how MT is used in practice, we applied MT to test two open-source bioinformatics programs, namely GNLab and SeqMap. In particular we show that MT is simple to implement, and is effective in detecting faults in a real-life program and some artificially fault-seeded programs. Further, we discuss how MT can be applied to test programs from various domains of bioinformatics.","Title: A revisit of three studies related to random testing.\nYear: 2015\n\nAbstract: Software testing is an approach that ensures the quality of software through execution, with a goal being to reveal failures and other problems as quickly as possible. Test case selection is a fundamental issue in software testing, and has generated a large body of research, especially with regards to the effectiveness of random testing (RT), where test cases are randomly selected from the software’s input domain. In this paper, we revisit three of our previous studies. The first study investigated a sufficient condition for partition testing (PT) to outperform RT, and was motivated by various controversial and conflicting results suggesting that sometimes PT performed better than RT, and sometimes the opposite. The second study aimed at enhancing RT itself, and was motivated by the fact that RT continues to be a fundamental and popular testing technique. This second study enhanced RT fault detection effectiveness by making use of the common observation that failure-causing inputs tend to cluster together, and resulted in a new family of RT techniques: adaptive random testing (ART), which is random testing with an even spread of test cases across the input domain. Following the successful use of failure-causing region contiguity insights to develop ART, we conducted a third study on how to make use of other characteristics of failure-causing inputs to develop more effective test case selection strategies. This third study revealed how best to approach testing strategies when certain characteristics of the failure-causing inputs are known, and produced some interesting and important results. In revisiting these three previous studies, we explore their unexpected commonalities, and identify diversity as a key concept underlying their effectiveness. This observation further prompted us to examine whether or not such a concept plays a role in other areas of software testing, and our conclusion is that, yes, diversity appears to be one of the most important concepts in the field of software testing.","Title: Adaptive and Random Partition Software Testing\nYear: 2014\n\nAbstract: Random testing (RT) and subdomain testing are two major software testing strategies. Their simplicity makes them likely the most efficient testing strategies with respect to the time required for test case selection. However, the disadvantage of RT is its defect detection effectiveness. Adaptive testing (AT) is a feedback-based software testing strategy that has been shown to be more effective than RT and partition testing (PT). However, a major concern in the application of AT is its complexity and computational cost for test case selection. In this paper, we propose a hybrid approach that uses AT and random partition testing (RPT) in an alternating manner. The motivation for this approach is that both strategies are employed such that the underlying computational complexity of AT is reduced by introducing RPT into the testing process without affecting the defect detection effectiveness. A case study with seven real-life subject programs is presented. The experimental results demonstrate that this novel strategy considerably reduces the computational overhead of the original AT strategy but still outperforms the pure RT strategy and PT strategy in terms of the number of test cases used to detect and remove a given number of defects. In addition, a sensitivity analysis is conducted to validate the robustness of our strategy.","Title: How Can Non-Technical End Users Effectively Test Their Spreadsheets?\nYear: 2014\n\nAbstract: Purpose - An alarming number of spreadsheet faults have been reported in the literature, indicating that effective and easy-to-apply spreadsheet testing techniques are not available for \"non-technical,\" end-user programmers. The purpose of this paper is to alleviate the problem by introducing a metamorphic testing (MT) technique for spreadsheets.Design/methodology/approach - The paper discussed four common challenges encountered by end-user programmers when testing a spreadsheet. The MT technique was then discussed and how it could be used to solve the common challenges was explained. An experiment involving several \"real-world\" spreadsheets was performed to determine the viability and effectiveness of MT.Findings - The experiment confirmed that MT is highly effective in spreadsheet fault detection, and yet MT is a general technique that can be easily used by end-user programmers to test a large variety of spreadsheet applications.Originality/value - The paper provides a detailed discussion of some common challenges of spreadsheet testing encountered by end-user programmers. To the best of the authors knowledge, the paper is the first that includes an empirical study of how effective MT is in spreadsheet fault detection from an end-user programmer's perspective.","Title: Bottom-up Integration Testing with the Technique of Metamorphic Testing\nYear: 2014\n\nAbstract: In previous studies on the application of Metamorphic Testing (MT), testing was usually conducted at the system level directly, without any well-planned integration strategy. This could lead to a difficulty in constructing Metamorphic Relations (MRs), as well as tracking and debugging the faults. On the other hand, traditional integration testing requires extra cost. In this paper, we combine the bottom-up integration approach with MT to address all the above problems. We use the Feature Selection (FS) system to illustrate our method and a 2-phase MT is conducted. With this 2-phase MT method, we can ease the MR identification and provide a clear hierarchy to easily track and isolate the faults for a complex system. Moreover, since such an integration approach is logically achieved with MRs, it does not need to have those specific set-ups as required in traditional integration testing.","Title: Classification-tree restructuring methodologies: a new perspective\nYear: 2002\n\nAbstract: The classification-tree method developed by Grochtmann et al. (1993, 1995) provided a useful approach for constructing test cases from functional specifications. It was automated by Chen and Poon (1997, 1998) through their tree construction methodology. In a follow-up study, Chen and Poon found that the effectiveness of constructing legitimate test cases could be improved under certain circumstances via a classification-tree restructuring algorithm. We develop another tree restructuring algorithm to cater for other situations not covered previously. The algorithms complement each other. We also compare the relative effectiveness of these algorithms and provide guidelines on applying them in practice","Title: A new approach for network vulnerability analysis\nYear: 2015\n\nAbstract: We propose in this paper a novel approach to analyze network vulnerability and to obtain a quantitative value representing the level of security achieved in an arbitrary network. Unlike previous graph-based algorithms that generate attack trees (or graphs) to cover all possible sequences of vulnerabilities and therefore are not scalable, our method utilizes the attack graphpsilas principles, but directly analyzes and produces the desired security measure for a network without building the actual attack graph. The proposed approach relies on a unique evaluation of vulnerability metric defined in this paper and is demonstrated through an example of a network that provides voice over IP services.","Title: Metamorphic Testing for Software Quality Assessment: A Study of Search Engines\nYear: 2016\n\nAbstract: Metamorphic testing is a testing technique that can be used to verify the functional correctness of software in the absence of an ideal oracle. This paper extends metamorphic testing into a user-oriented approach to software verification, validation, and quality assessment, and conducts large scale empirical studies with four major web search engines: Google, Bing, Chinese Bing, and Baidu. These search engines are very difficult to test and assess using conventional approaches owing to the lack of an objective and generally recognized oracle. The results are useful for both search engine developers and users, and demonstrate that our approach can effectively alleviate the oracle problem and challenges surrounding a lack of specifications when verifying, validating, and evaluating large and complex software systems.","Title: Metamorphic testing: a simple method for alleviating the test oracle problem\nYear: 2015\n\nAbstract: The test oracle problem is regarded as one of the most challenging problems in software testing. Metamorphic testing has been developed to alleviate this problem, which is done using the relations involving relevant inputs and their outputs. This keynote speech will provide a summary of the state-of-the-art of metamorphic testing.","Title: MT4WS: an automated metamorphic testing system for web services\nYear: 2016\n\nAbstract: AbstractThe use of web services has been growing significantly, with increasingly large numbers of applications being implemented through the web. A difficulty associated with this development is the quality assurance of these services, specifically the challenges encountered when testing the applications - amongst other things, testers may not have access to the source code, and the correctness of the output may not be easily ascertained known as the oracle problem. Metamorphic testing MT has been introduced as a technique to alleviate the oracle problem. MT makes use of properties of the software under test, known as metamorphic relations, and checks whether or not these relations are violated. Since MT does not require source code to generate the metamorphic relations, it is suitable for testing web services-based applications. We have designed an XML-based language representation to facilitate the formalisation of metamorphic relations, the generation of follow-up test cases, and the verification of the test results. Based on this, we have also developed a tool to support the automation of MT for web service applications. This tool has been used in an experiment to test web services, the evaluation of which is reported in this paper.","Title: Using Partition Information to Prioritize Test Cases for Fault Localization\nYear: 2015\n\nAbstract: Fault Localization Prioritization (FLP) aims at reordering existing test cases so that the location of detected faulty components can be identified earlier, using certain fault localization techniques. Although some researchers have proposed adaptive prioritization strategies with white-box code coverage information, such information may not always be available. In this paper, we address the FLP problem using black-box information derived from partitioning the input domain. Based on the well-known technique of Spectra-Based Fault Localization (SBFL), three test case prioritization strategies are designed following some basic SBFL heuristics. The implementation of these proposed strategies relies only on the partition information, and does not require any test case execution history. Experiments show that our strategies, when compared with pure random selection, result in a faster localization of faulty statements, reducing the number of test case executions required. Here, we analyze the characteristics and merits of the three proposed strategies.","Title: A Revisit of a Theoretical Analysis on Spectrum-Based Fault Localization\nYear: 2015\n\nAbstract: As a promising automatic fault localization technique, Spectrum-Based Fault Localization (SBFL) has been proposed and widely studied for years, in which the effectiveness of risk evaluation formula is one of the most popular research topics. We have developed a framework to support the theoretical analysis of risk evaluation formulas, via subset relations. In this paper, we would like to further justify the assumptions used in our framework, which are not only to make the theoretical analysis be feasible, but they are actually required either explicitly or implicitly by SBFL.","Title: Metamorphic Testing for Cybersecurity.\nYear: 2016\n\nAbstract: Metamorphic testing (MT) can enhance security testing by providing an alternative to using a test oracle, which is often unavailable or impractical. The authors report how MT detected previously unknown bugs in real-world critical applications such as code obfuscators, giving evidence that software testing requires diverse perspectives to achieve greater cybersecurity.","Title: Metamorphic testing as a test case selection strategy.\nYear: 2016\n\nAbstract: 软件测试通过运行测试用例, 观察被测软件的输出结果是否符合预期结果来发现潜藏的故障。 然而, 判定测试输出是否正确往往会成为软件测试面临的一个挑战(称为测试预期问题)。 蜕变测试通过建立被测软件输入变量域和输出结果域的关系(称为蜕变关系), 以蜕变关系判定测试执行的正确性。 蜕变测试不仅具有良好的故障检测能力, 也是一种测试用例选择方法。 本文侧重报告蜕变测试作为一种测试用例选择策略的几个成功案例。","Title: Looking for an MR?: try METWiki today.\nYear: 2016\n\nAbstract: Metamorphic Testing (MT) has been demonstrated to successfully alleviate oracle problems in many areas, including machine learning, compilers, bioinformatics, etc. However, given a new MT task, it is still very challenging to identify enough Metamorphic Relations (MRs) which are key components of MT. Aiming at this problem, we revisited previous MT applications and realized that they could form a very valuable database. Currently there is a lack of efficient link to get testers access these historical data. Therefore, in this paper, we propose to build METWiki, an MR repository, for collection and retrieval of these MRs. By providing exploration and search facilities, testers can find their desired MRs for reuse, reference, or inference. We also illustrate three sample usages of METWiki, which show important illuminations on how MRs can be obtained in practice.","Title: The impact of source test case selection on the effectiveness of metamorphic testing.\nYear: 2016\n\nAbstract: Metamorphic Testing (MT) aims to alleviate the oracle problem. In MT, testers define metamorphic relations (MRs) which are used to generate new test cases (referred to as follow-up test cases) from the available test cases (referred to as source test cases). Both source and follow-up test cases are executed and their outputs are verified against the relevant MRs, of which any violation implies that the software under test is faulty. So far, the research on the effectiveness of MT has been focused on the selection of better MRs (that is, MRs that are more likely to be violated). In addition to MR selection, the source and follow-up test cases may also affect the effectiveness of MT. Since follow-up test cases are defined by the source test cases and MRs, selection of source test cases will then affect the effectiveness of MT. However, in existing MT studies, random testing is commonly adopted as the test case selection strategy for source test cases. This study aims to investigate the impact of source test cases on the effectiveness of MT. Since Adaptive Random Testing (ART) has been developed as an enhancement to Random Testing (RT), this study will focus on comparing the performance of RT and ART as source test case selection strategies on the effectiveness of MT. Experiment results show that ART outperforms RT on enhancing the effectiveness of MT.","Title: A cloud-based framework for applying metamorphic testing to a bioinformatics pipeline.\nYear: 2016\n\nAbstract: Testing of bioinformatics software often suffers from the oracle problem, especially when testing software that analyses human genome sequencing data. Metamorphic testing has been proposed to alleviate the oracle problem. Nonetheless, smaller research or clinical centres may be challenged by the complexity and resources required to implement a suitable metamorphic testing framework in practice. This paper presents a case study on how a cloud-based metamorphic testing framework can be applied to a widely used genomic sequencing pipeline, and discusses the future of implementing large-scale on-demand automated metamorphic testing using cloud-based resources.","Title: Input-Driven Active Testing of Multi-threaded Programs\nYear: 2015\n\nAbstract: It is still a challenge to select \"good\" test inputs for concurrent programs within limited testing resources. We present in this paper a test case diversity metric for multi-threaded programs, which evaluates a test input with its effect in exposing concurrent thread interactions. We then propose an input-driven active testing approach with two test input selection strategies based on our test case diversity metric. We implement our testing approach based on Maple, an interleaving coverage-driven active testing tool. The effectiveness and efficiency of our testing approach are compared closely with Maple, which on its own is supplied with random test inputs. Experimental results show that our testing approach can outperform the original active testing approach in the number of test inputs executed and the time usage for fulfilling the interleaving coverage criterion of Maple. The selected test inputs based on our test case diversity metric are very cost-effective in exposing concurrent thread interactions and hence can help detect concurrency bugs with less cost and effort.","Title: A Cost-Effective Random Testing Method for Programs with Non-Numeric Inputs.\nYear: 2016\n\nAbstract: Random testing (RT) has been widely used in the testing of various software and hardware systems. Adaptive random testing (ART) is a family of random testing techniques that aim to enhance the failure-detection effectiveness of RT by spreading random test cases evenly throughout the input domain. ART has been empirically shown to be effective on software with numeric inputs. However, there are two aspects of ART that need to be addressed to render its adoption more widespread—applicability to programs with non-numeric inputs, and the high computation overhead of many ART algorithms. We present a linear-order ART algorithm for software with non-numeric inputs. The key requirement for using ART with non-numeric inputs is an appropriate “distance” measure. We use the concepts of categories and choices from category-partition testing to formulate such a measure. We investigate the failure-detection effectiveness of our technique by performing an empirical study on 14 object programs, using two standard metrics—F-measure and P-measure. Our ART algorithm statistically significantly outperforms RT on 10 of the 14 programs studied, and exhibits performance similar to RT on three of the four remaining programs. The selection overhead of our ART algorithm is close to that of RT.","Title: Test Case Prioritization Using Adaptive Random Sequence with Category-Partition-Based Distance\nYear: 2016\n\nAbstract: Test case prioritization schedules test cases in a certain order aiming to improve the effectiveness of regression testing. Random sequence is a basic and simple prioritization technique, while Adaptive Random Sequence (ARS) makes use of extra information to improve the diversity of random sequence. Some researchers have proposed prioritization techniques using ARS with white-box information, such as code coverage information, or with black-box information, such as string distances of the input data. In this paper, we propose new black-box test case prioritization techniques using ARS, and the diversity of test cases is assessed by category-partition-based distance. Our experimental studies show that these new techniques deliver higher fault-detection effectiveness than random prioritization, especially in the case of smaller ratio of failed test cases. In addition, in the comparison of different distance metrics, techniques with category-partition-based distance generally deliver better fault-detection effectiveness and efficiency, meanwhile in the comparison of different ordering algorithms, our ARS-based ordering algorithms usually have comparable fault-detection effectiveness but much lower computation overhead, and thus are much more cost-effective.","Title: Error Trapping and Metamorphic Testing for Spreadsheet Failure Detection.\nYear: 2017\n\nAbstract: This study deepens the research on error trapping ET and metamorphic testing MT for detecting spreadsheet failures. It is observed that some spreadsheet developers and testers are confused between ET and MT, because the two techniques are similar to each other in some aspects. Inspired by the observation, this paper first outlines the main concepts of ET and MT using several examples for illustration. This is followed by discussing an experiment with a view to investigating and comparing the failure detection capabilities of the two techniques. The results of the experiment indicate that neither technique is sufficient in spreadsheet testing. Rather, ET and MT are complementary and they should be used together in spreadsheet testing whenever possible.","Title: A metamorphic testing approach for supporting program repair without the need for a test oracle.\nYear: 2017\n\nAbstract: •A framework to support the integration of metamorphic testing with automated program repair.•An automated program repair tool MT-GenProg.•An empirical study of the effectiveness of the integrated technique.","Title: An Adaptive Sequence Approach for OOS Test Case Prioritization\nYear: 2016\n\nAbstract: Test case prioritization (TCP) attempts to improve fault detection effectiveness by scheduling important test cases earlier, where important is determined by some criteria and strategy. Adaptive random sequences (ARSs) may be applied to improve the effectiveness of TCP in black-box testing. In this paper, to improve the effectiveness of TCP for object-oriented software, we present an ARS approach based on clustering techniques. In the proposed approach, test cases are clustered according to the number of objects and methods, using two clustering algorithms - K-means and K-medoids. Our proposed sampling strategy can construct ARSs within the clustering framework, constructing two ARS sequences based on the two clustering algorithms, which results in generated test cases with different execution sequences. We also report on experimental studies to verify the proposed approach, with the results showing that our approach can enhance the probability of earlier fault detection, and deliver higher effectiveness than random prioritization.","Title: Human Competitiveness of Genetic Programming in Spectrum-Based Fault Localisation: Theoretical and Empirical Analysis.\nYear: 2017\n\nAbstract: We report on the application of Genetic Programming to Software Fault Localisation, a problem in the area of Search-Based Software Engineering (SBSE). We give both empirical and theoretical evidence for the human competitiveness of the evolved fault localisation formulæ under the single fault scenario, compared to those generated by human ingenuity and reported in many papers, published over more than a decade. Though there have been previous human competitive results claimed for SBSE problems, this is the first time that evolved solutions have been formally proved to be human competitive. We further prove that no future human investigation could outperform the evolved solutions. We complement these proofs with an empirical analysis of both human and evolved solutions, which indicates that the evolved solutions are not only theoretically human competitive, but also convey similar practical benefits to human-evolved counterparts.","Title: A Similarity Metric for the Inputs of OO Programs and Its Application in Adaptive Random Testing.\nYear: 2017\n\nAbstract: Random testing (RT) has been identified as one of the most popular testing techniques, due to its simplicity and ease of automation. Adaptive random testing (ART) has been proposed as an enhancement to RT, improving its fault-detection effectiveness by evenly spreading random test inputs across the input domain. To achieve the even spreading, ART makes use of distance measurements between consecut...","Title: Harnessing Multiple Source Test Cases in Metamorphic Testing: A Case Study in Bioinformatics.\nYear: 2017\n\nAbstract: Metamorphic testing (MT) has been applied to software verification, validation and quality assessment. In most previous studies, research has focused on deriving metamorphic relations (MRs) such that the input of one or more follow-up test cases is generated from one source test case. We note that some programs under test (PUT) naturally take multiple inputs and process them simultaneously to generate multiple outputs. This type of programs are common in the field of big data analysis and bioinformatics. This means, in the source execution of the program, we can obtain multiple outputs from multiple source test cases. Here we consider a type of MR in which multiple follow-up test cases are generated from multiple source test cases simultaneously. We hypothesise that harnessing the outputs from multiple source test cases enables us to obtain additional information about the PUT, and therefore allows us to construct more effective MRs. In this paper, we designed a new MR to test a popular RNA sequence alignment program. Since the MR was designed based on a desirable property of the PUT (which uses a complex heuristic algorithm) rather than a necessary property, violation of this MR indicates the program outputs deviate from user expectation, hence this MR can be used for assessing the quality of the outputs. Furthermore, we note that outputs of the follow-up test cases allow us to putatively assign alignment information to some sequences that were not aligned in the source test cases, hence potentially identifying and correcting these 'false negative' outputs. We believe this case study provides important insight into designing MRs based on multiple source test cases, and how testing results can be used to improve the performance of some heuristic-based programs.","Title: Metamorphic Testing for Adobe Data Analytics Software.\nYear: 2017\n\nAbstract: It is challenging to test data analytics software because a test oracle might not be available. This study reports our experience of applying metamorphic testing to Adobe's data analytics software that is used for anomaly detection in a set of time series data. We make use of geometric transformations to build metamorphic relations and generate simple time series data as the source test cases. The results of this study show that metamorphic testing is highly effective for both verification and validation purposes. An investigation of the issues detected during metamorphic testing revealed three bugs in the software under test.","Title: A Revisit of the Integration of Metamorphic Testing and Test Suite Based Automated Program Repair.\nYear: 2017\n\nAbstract: The technique of metamorphic testing (MT) has been integrated with test suite based automated program repair (APR) to alleviate the test oracle problem of APR. The proposed integration yields APR-MT techniques, which can be applied regardless of the existence of a test oracle. In a previous study, the feasibility and effectiveness of the APR-MT technique have been demonstrated via GenProg-MT, an integration of MT and the APR technique GenProg. This paper aims to complement our previous study to investigate the feasibility and effectiveness of APR-MT across different categories of APR techniques. We present the integration of MT with CETI, an APR technique belonging to a different category to GenProg, and conduct experimental analysis on the integrated technique CETI-MT, showing that CETI-MT is comparable to CETI in terms of the repair effectiveness. These results not only demonstrate the feasibility of integrating MT with different categories of APR techniques, but also consolidate the effectiveness of APR-MT techniques, hence increasing the practical benefits of APR-MT techniques.","Title: Prioritizing random combinatorial test suites.\nYear: 2017\n\nAbstract: The behaviour of a system under test can be influenced by several factors, such as system configurations, user inputs, and so on. It has also been observed that many failures are caused by only a small number of factors. Combinatorial testing aims at generating a small-sized test suite that can identify such failures. Random testing, on the other hand, selects test cases in a random manner, but has sometimes achieved similar failure-finding performance to combinatorial testing. Due to limited testing resources, test case prioritization is often employed, to attempt to identify failures as early as possible. Many prioritization studies, however, have only focused on test suites constructed by combinatorial testing, ignoring randomly constructed test suites. In this paper, we report on an investigation of test case prioritization for random combinatorial test suites. We conducted a series of empirical studies involving three real-world programs, each of which used twelve random combinatorial test suites, and adopted the well-known test case prioritization technique fixed-strength interaction coverage based prioritization (FICBP). Results from the studies indicate that, FICBP with high prioritization strength achieves better interaction coverage rate than with low prioritization strength. Furthermore, when the size of the random test suite is small, it would be better to assign a prioritization strength of 2; but otherwise, a strength of 3 would be more appropriate.","Title: Integration of Metamorphic Testing with Program Repair Methods Based on Adaptive Search Strategies and Program Equivalence.\nYear: 2017\n\nAbstract: Automated program repair (APR) is a promising approach to localize faults and generate patches for program under repair. One of the test suite based APR techniques, a method leveraging Adaptive search strategies and program Equivalence (AE), has been commonly used for program repair. AE assumes the availability of test oracles, which brings the oracle problem to AE repair procedure. Metamorphic Testing (MT) has been introduced to alleviate the test oracle problem, and it tests the correctness of programs through metamorphic relations (MRs) which are relations among multiple inputs and outputs. This paper presents an integration of AE with MT (referred to as AE-MT) to extend the applicability of AE to those applications with oracle problems. To evaluate the repair effectiveness of AE-MT, an empirical study is conducted against Intro Class benchmark. We conclude that AE-MT outperforms AE in terms of success rate, but is of lower repair quality than AE.","Title: Testing Proportional-Integral-Derivative (PID) Controller with Metamorphic Testing\nYear: 2017\n\nAbstract: The controller program is the core of a safety-critical control system. However, the testing of controller program has been facing challenges because of the oracle problem. Since Proportional-Integral-Derivative (PID) controller is the most commonly used controller in the industry, this paper proposes to apply Metamorphic Testing (MT) to test it. Our experimental results show that MT is effective in testing PID controller.","Title: Identifying Failed Test Cases Through Metamorphic Testing\nYear: 2017\n\nAbstract: When testing a program without a test oracle, it is impossible to know whether a test case will lead to a failure or not. The infeasibility to identify a failed test case severely restricts the applicability of many testing, debugging and fault localization techniques. However, with the help of Metamorphic Testing (MT) which was proposed to alleviate the test oracle problem, we are able to estimate how likely a test case is a failed test case.","Title: Test case prioritization for object-oriented software: An adaptive random sequence approach based on clustering.\nYear: 2018\n\nAbstract: •A new dissimilarity metric (OMV, object method vector) for OOS test cases.•Two clustering methods to generate adaptive random sequences for OOS test cases.•A sampling strategy to construct the adaptive random sequences.•Conducting empirical studies to verify the proposed approaches.","Title: Out of sight, out of mind: a distance-aware forgetting strategy for adaptive random testing.\nYear: 2017\n\nAbstract: Adaptive random testing (ART) achieves better failure-detection effectiveness than random testing by increasing the diversity of test cases. However, the intention of ensuring even spread of test cases inevitably causes an overhead problem. Although two basic forgetting strategies (i.e. random forgetting and consecutive retention) were proposed to reduce the computation cost of ART, they only considered the temporal distribution of test cases. In the paper, we presented a distance-aware forgetting strategy for the fixed size candidate set version of ART (DF-FSCS), in which the spatial distribution of test cases is taken into consideration. For a given candidate, the test cases out of its “sight” are ignored to reduce the distance computation cost. At the same time, the dynamic adjustment for partitioning and the second-round forgetting are adopted to ensure the linear complexity of DF-FSCS algorithm. Both simulation analysis and empirical study are employed to investigate the efficiency and effectiveness of DF-FSCS. The experimental results show that DF-FSCS significantly outperforms the classical ART algorithm FSCS-ART in efficiency, and has comparable failure-detection effectiveness. Com-pared with two basic forgetting methods, DF-FSCS is better in both efficiency and effectiveness. In contrast with a typical linear-time ART algorithm RBCVT-Fast, our algorithm requires less computational overhead and exhibits the similar failure-detection capability. In addition, DF-FSCS has more reliable performance than RBCVT-Fast in detecting failures for the programs with high-dimensional input domain.","Title: An experimental analysis of fault detection capabilities of covering array constructors.\nYear: 2018\n\nAbstract: Combinatorial Interaction Testing (CIT) aims at constructing an effective test suite, such as a Covering Array (CA), that can detect faults that are caused by the interaction of parameters. In this paper, we report on some empirical studies conducted to examine the fault detection capabilities of five popular CA constructors: ACTS, Jenny, PICT, CASA, and TCA. The experimental results indicate that Jenny has the best performance, because it achieves better fault detection than the other four constructors in many cases. Our results also indicate that CAs generated using ACTS, PICT, or CASA should be prioritized before testing.","Title: On the Selection of Strength for Fixed-Strength Interaction Coverage Based Prioritization\nYear: 2018\n\nAbstract: Abstract test cases are derived by modeling the system under test, and have been widely applied in practice, such as for software product line testing and combinatorial testing. Abstract test case prioritization (ATCP) is used to prioritize abstract test cases and aims at achieving higher rates of fault detection. Many ATCP algorithms have been proposed, using different prioritization criteria and information. One ATCP approach makes use of fixed-strength level-combinations information covered by abstract test cases, and is called fixed-strength interaction coverage based prioritization (FICBP). Before using FICBP, the prioritization strength λ needs to be decided. Previous studies have generally focused on λ values ranging between 1 and 6. However, no study has investigated the appropriateness of such a range, nor how to assign the prioritization strength for FICBP. To answer these questions, this paper reports on an empirical study involving four real-life programs (each of which with six versions). The experimental results indicate that λ should be set approximately equal to a value corresponding to half of the number of parameters, when testing resources are sufficient. Our results also show that when testing resources are limited or insufficient, either small or large λ values are suggested for FICBP.","Title: A Validation and Quality Assessment Method with Metamorphic Relations for Unsupervised Machine Learning Software.\nYear: 2018\n\nAbstract: Unsupervised machine learning is a task of modeling the underlying structure of ``unlabeled datau0027u0027. Since learning algorithms have been incorporated into many real-world applications, validating the implementations of those algorithms becomes much more important in the aim of software quality assurance. However, validating unsupervised machine learning programs is challenging because there lacks of priori knowledge. Along this line, in this paper, we present a metamorphic testing based method for validating and characterizing unsupervised machine learning programs, and conduct an empirical study on a real-world machine learning tool. The results demonstrate to what extent a program may fit to the profile of a specific scenario, which help end-users or software practitioners comprehend its performance in a vivid and light-weight way. And the experimental findings also reveal the gap between theory and implementation in a software artifact which could be easily ignored by people without much practical experience. In our method, metamorphic relations can serve as one type of quality measure, and one type of guidelines for selecting suitable programs.","Title: Metamorphic Testing for Adobe Analytics Data Collection JavaScript Library.\nYear: 2018\n\nAbstract: In recent years, metamorphic testing has been successfully and systematically adopted within Adobe Systems to improve the cost effectiveness of its software process. In this industry experience report, we present a case where metamorphic testing has been applied to the Data Collection JavaScript Library of Adobe Analytics. This type of software is difficult to test using traditional approaches. The application of metamorphic testing alleviated the oracle problem, and detected real-life bugs in the system under test as well as compatibility problems between the system and its environment, namely, the Internet Explorer browser. Our results further justify the adoption of metamorphic testing as a simple yet effective approach in industrial settings.","Title: Enhancing Supervised Classifications with Metamorphic Relations.\nYear: 2018\n\nAbstract: We report on a novel use of metamorphic relations (MRs) in machine learning: instead of conducting metamorphic testing, we use MRs for the augmentation of the machine learning algorithms themselves. In particular, we report on how MRs can enable enhancements to an image classification problem of images containing hidden visual markers (\"Artcodes\").\n\nWorking on an original classifier, and using the characteristics of two different categories of images, two MRs, based on separation and occlusion, were used to improve the performance of the classifier. Our experimental results show that the MR-augmented classifier achieves better performance than the original classifier, algorithms, and extending the use of MRs beyond the context of software testing.","Title: Diversity driven adaptive test generation for concurrent data structures.\nYear: 2018\n\nAbstract: Abstract Context Testing concurrent data structures remains a notoriously challenging task, due to the nondeterminism of multi-threaded tests and the exponential explosion on the number of thread schedules. Objective We propose an automated approach to generate a series of concurrent test cases in an adaptive manner, i.e., the next test cases are generated with the guarantee to discover the thread schedules that have not yet been activated by the previous test cases. Method Two diversity metrics are presented to induce such adaptive test cases from a static and a dynamic perspective, respectively. The static metric enforces the diversity in the program structures of the test cases; while the dynamic one enforces the diversity in their capabilities of exposing untested thread schedules. We implement three adaptive test generation approaches for C/C++ concurrent data structures, based on the state-of-the-art active testing engine Maple. Results We then report an empirical study with 9 real-world C/C++ concurrent data structures, which demonstrates the efficiency of our test generation approaches in terms of the number of thread schedules discovered, as well as the time and the number of tests required for testing a concurrent data structure. Conclusion Hence, by using diverse test cases derived from the static and dynamic perspectives, our adaptive test generation approaches can deliver a more efficient coverage of the thread schedules of the concurrent data structure under test.","Title: Adaptive Random Testing In Detecting Layout Faults Of Web Applications\nYear: 2018\n\nAbstract: As part of a software testing process, output verification poses a challenge when the output is not numeric or textual, such as graphical. The industry practice of using human oracles (testers) to observe and verify the correctness of the actual results is both expensive and error-prone. In particular, this practice is usually unsustainable when developing web applications - the most popular software of our era. This is because web applications change frequently due to the fast-evolving requirements amid popular demand. To improve the cost effectiveness of browser output verification, in this study we design failure-based testing techniques and evaluate the effectiveness and efficiency thereof in the context of web testing. With a novel application of the concept of adaptive random sequence (ARS), our approach leverages peculiar characteristics of failure patterns found in browser layout rendering. An empirical study shows that the use of failure patterns and inclination to guide the testing flow leads to more cost-effective results than other classic methods. This study extends the application of ARSs from the input space of programs to their output space, and also shows that adaptive random testing (ART) can outperform random testing (RT) in both failure detection effectiveness (in terms of F-measure) and failure detection efficiency (in terms of execution time).","Title: An Empirical Comparison of Fixed-Strength and Mixed-Strength for Interaction Coverage Based Prioritization.\nYear: 2018\n\nAbstract: Test case prioritization (TCP) plays an important role in identifying, characterizing, diagnosing, and correcting faults quickly. The TCP has been widely used to order test cases of different types, including model inputs (also called abstract test cases). Model inputs are constructed by modeling the program according to its input parameters, values, and constraints, and has been used in different testing methods, such as combinatorial interaction testing and software product line testing. The Interaction coverage-based TCP (ICTCP) uses interaction coverage information derived from the model input to order inputs. Previous studies have focused generally on the fixed-strength ICTCP, which adopts a fixed strength (i.e., the level of parameter interactions) to support the ICTCP process. It is generally accepted that using more strengths for ICTCP, i.e., mixed-strength ICTCP, may give better ordering than fixed-strength. To confirm whether mixed-strength is better than fixed-strength, in this paper, we report on an extensive empirical study using five real-world programs (written in C), each of which has six versions. The results of the empirical studies show that mixed-strength has better rates of interaction coverage overall than fixed-strength, but they have very similar rates of fault detection. Our results also show that fixed-strength should be used instead of the mixed-strength at the later stage of software testing. Finally, we offer some practical guidelines for testers when using interaction coverage information to prioritize model inputs, under different testing scenarios and resources.","Title: On the analysis of spectrum based fault localization using hitting sets.\nYear: 2019\n\nAbstract: •Two variants of Sendys to patch its NOR problem and improve its performance.•First comprehensive theoretical analysis on Sendys and its variants.•A short-cut reformulation of the enhanced Sendys with the best performance.•Empirical studies on single and multiple faults to complement theoretical analysis.","Title: Adaptive Partition Testing.\nYear: 2019\n\nAbstract: Random testing and partition testing are two major families of software testing techniques. They have been compared both theoretically and empirically in numerous studies for decades, and it has been widely acknowledged that they have their own advantages and disadvantages and that their innate characteristics are fairly complementary to each other. Some work has been conducted to develop advanced...","Title: Metamorphic testing: A new student engagement approach for a new software testing paradigm\nYear: 2016\n\nAbstract: Software testing, as part of the software quality assurance processes in software engineering (SE), is seldom cited as the most engaging part of a software engineer's training. In spite of its importance, it was often a neglected area, and only recently, with the adoption of more agile methodologies, has testing come to the fore. Testers face challenges, including the need to be able to identify when software is not behaving as expected. Metamorphic Testing (MT) first appeared twenty years ago in an effort to help testers facing the oracle problem (not having a mechanism to determine correct software behavior). Although MT is simple in concept, it has demonstrated very impressive fault-finding ability, and has recently been attracting a great deal of interest. Training students and practitioners to effectively apply MT has become an important goal, but to date, no textbook or guidelines have been made readily available. This paper, written by some of the leading voices in the MT community, is a sharing of some of the experiences, reflections and insights gained through teaching MT (and other related subjects). These experiences indicate that not only is MT effective in industry and at fault-finding, it has the potential to really engage students in creative SE classroom activities.","Title: Metamorphic Testing: A Review of Challenges and Opportunities.\nYear: 2018\n\nAbstract: Metamorphic testing is an approach to both test case generation and test result verification. A central element is a set of metamorphic relations, which are necessary properties of the target function or algorithm in relation to multiple inputs and their expected outputs. Since its first publication, we have witnessed a rapidly increasing body of work examining metamorphic testing from various perspectives, including metamorphic relation identification, test case generation, integration with other software engineering techniques, and the validation and evaluation of software systems. In this article, we review the current research of metamorphic testing and discuss the challenges yet to be addressed. We also present visions for further improvement of metamorphic testing and highlight opportunities for new research.","Title: Prioritizing Abstract Test Cases: An Empirical Study\nYear: 2019\n\nAbstract: Test-case prioritisation (TCP) attempts to schedule the order of test-case execution such that faults can be detected as quickly as possible. TCP has been widely applied in many testing scenarios such as regression testing and fault localisation. Abstract test cases (ATCs) are derived from models of the system under test and have been applied to many testing environments such as model-based testing and combinatorial interaction testing. Although various empirical and analytical comparisons for some ATC prioritisation (ATCP) techniques have been conducted, to the best of the authors’ knowledge, no comparative study focusing on the most current techniques has yet been reported. In this study, they investigated 18 ATCP techniques, categorised into four classes. They conducted a comprehensive empirical study to compare 16 of the 18 ATCP techniques in terms of their testing effectiveness and efficiency. They found that different ATCP techniques could be cost-effective in different testing scenarios, allowing us to present recommendations and guidelines for which techniques to use under what conditions.","Title: Metamorphic Testing: A Simple Yet Effective Approach for Testing Scientific Software\nYear: 2019\n\nAbstract: Testing scientific software is a difficult task due to their inherent complexity and the lack of test oracles. In addition, these software systems are usually developed by \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">end-user developers</italic>\n who are not normally trained as professional software developers nor testers. These factors often lead to inadequate testing. \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Metamorphic testing (MT)</italic>\n is a simple yet effective testing technique for testing such applications. Even though MT is a wellknown technique in the software testing community, it is not very well utilized by the scientific software developers. The objective of this paper is to present MT as an effective technique for testing scientific software. To this end, we discuss why MT is an appropriate testing technique for scientists and engineers who are not primarily trained as software developers. Specifically, how it can be used to conduct systematic and effective testing on programs that do not have test oracles without requiring additional testing tools.","Title: Metamorphic Testing: Testing the Untestable\nYear: 2020\n\nAbstract: What if we could know that a program is buggy, even if we could not tell whether or not its observed output is correct? Metamorphic testing provides this ability. This article explains the basics of the technique.","Title: KDFC-ART: a KD-tree approach to enhancing Fixed-size-Candidate-set Adaptive Random Testing\nYear: 2019\n\nAbstract: Adaptive random testing (ART) was developed as an enhanced version of random testing to increase the effectiveness of detecting failures in programs by spreading the test cases evenly over the input space. However, heavy computation may be incurred. In this paper, three enhanced algorithms for fixed-size-candidate-set ART (FSCS-ART) are proposed based on the \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><tex-math notation=\"LaTeX\">$k$</tex-math></inline-formula>\n-dimensional tree (KD-tree) structure. The first algorithm Naive-KDFC constructs a KD-tree by splitting the input space with respect to every dimension successively in a round-robin fashion. The second algorithm SemiBal-KDFC improves the balance of the KD-tree by prioritizing the splitting according to the spread in each dimension. In order to control the number of traversed nodes in backtracking, the third algorithm LimBal-KDFC introduces an upper bound for the nodes involved. Simulation and empirical studies have been conducted to investigate the efficiency and effectiveness of the three algorithms. The experimental results show that these algorithms significantly reduce the computation time of the original FSCS-ART for low dimensions and for the case of high dimensions with low failure rates. The efficiency of SemiBal-KDFC is better than that of Naive-KDFC when the dimension is no more than 8, but LimBal-KDFC is the most efficient of all three. Although the limited backtracking leads only to an approximate nearest neighbor in LimBal-KDFC, its failure-detection effectiveness is, in fact, better than FSCS-ART in high-dimensional input spaces and has no significant deterioration in low-dimensional spaces.","Title: Metamorphic relations for detection of performance anomalies\nYear: 2019\n\nAbstract: Metamorphic relations can be used to improve performance testing by comparing successive runs of the software under test. We examine one such metamorphic relation for page load times, which we used to discover and repair a race condition in the Adobe Experience Platform Launch Tag Manager. Histograms for page load times had different modalities, which alerted us to the presence of the bug. We discuss the need for performance measures in addition to the popular mean and standard deviation. We describe two approaches to automatically determine modality: Gaussian Mixture Models and the Silverman Test for Multimodality. Metamorphic relations which involve these performance measures can be used to alert engineers to the presence of performance anomalies.","Title: Using metamorphic relations to verify and enhance Artcode classification\nYear: 2021\n\nAbstract: Software testing is often hindered where it is impossible or impractical to determine the correctness of the behaviour or output of the software under test (SUT), a situation known as the oracle problem. An example of an area facing the oracle problem is automatic image classification, using machine learning to classify an input image as one of a set of predefined classes. An approach to software testing that alleviates the oracle problem is metamorphic testing (MT). While traditional software testing examines the correctness of individual test cases, MT instead examines the relations amongst multiple executions of test cases and their outputs. These relations are called metamorphic relations (MRs): if an MR is found to be violated, then a fault must exist in the SUT. This paper examines the problem of classifying images containing visually hidden markers called Artcodes, and applies MT to verify and enhance the trained classifiers. This paper further examines two MRs, Separation and Occlusion, and reports on their capability in verifying the image classification using one-way analysis of variance (ANOVA) in conjunction with three other statistical analysis methods: t-test (for unequal variances), Kruskal–Wallis test, and Dunnett’s test. In addition to our previously-studied classifier, that used Random Forests, we introduce a new classifier that uses a support vector machine, and present its MR-augmented version. Experimental evaluations across a number of performance metrics show that the augmented classifiers can achieve better performance than non-augmented classifiers. This paper also analyses how the enhanced performance is obtained.","Title: Testing multiple linear regression systems with metamorphic testing\nYear: 2021\n\nAbstract: Regression is one of the most commonly used statistical techniques. However, testing regression systems is a great challenge because of the absence of test oracle in general. In this paper, we show that Metamorphic Testing is an effective approach to test multiple linear regression systems. In doing so, we identify intrinsic mathematical properties of linear regression, and then propose 11 Metamorphic Relations to be used for testing. Their effectiveness is examined using mutation analysis with a range of different regression programs. We further look at how the testing could be adopted in a more effective way. Our work is applicable to examine the reliability of predictive systems based on regression that has been widely used in economics, engineering and science, as well as of the regression calculation manipulated by statistical users.","Title: New visions on metamorphic testing after a quarter of a century of inception\nYear: 2021\n\nAbstract: ABSTRACTMetamorphic testing (MT) was introduced about a quarter of a century ago. It is increasingly being accepted by researchers and the industry as a useful testing technique. The studies, research results, applications, and extensions of MT have given us many insights and visions for its future. Our visions include: MRs will be a practical means to top up test case generation techniques, beyond the alleviation of the test oracle problem; MT will not only be a standalone technique, but conveniently integrated with other methods; MT and MRs will evolve beyond software testing, or even beyond verification; MRs may be anything that you can imagine, beyond the necessary properties of algorithms; MT research will be beyond empirical studies and move toward a theoretical foundation; MT will not only bring new concepts to software testing but also new concepts to other disciplines; MRs will alleviate the reliable test set problem beyond traditional approaches. These visions may help researchers explore the challenges and opportunities for MT in the next decade.","Title: Perception Matters: Detecting Perception Failures of VQA Models Using Metamorphic Testing\nYear: 2021\n\nAbstract: Visual question answering (VQA) takes an image and a natural-language question as input and returns a natural-language answer. To date, VQA models are primarily assessed by their accuracy on high-level reasoning questions. Nevertheless, Given that perception tasks (e.g., recognizing objects) are the building blocks in the compositional process required by high-level reasoning, there is a demanding need to gain insights into how much of a problem lowlevel perception is. Inspired by the principles of software metamorphic testing, we introduce MetaVQA, a model-agnostic framework for benchmarking perception capability of VQA models. Given an image i, MetaVQA is able to synthesize a low-level perception question q. It then jointly transforms (i, q) to one or a set of sub-questions and subimages. MetaVQA checks whether the answer to (i, q) satisfies metamorphic relationships (MRs), denoting perception consistency, with the composed answers of transformed questions and images. Violating MRs denotes a failure of answering perception questions. MetaVQA successfully detects over 4.9 million perception failures made by popular VQA models with metamorphic testing. The state-of-the-art VQA models (e.g., the champion of VQA 2020 Challenge) suffer from perception consistency problems. In contrast, the Oscar VQA models, by using anchor points to align questions and images, show generally better consistency in perception tasks. We hope MetaVQA will revitalize interest in enhancing the low-level perceptual abilities of VQA models, a cornerstone of high-level reasoning.","Title: BMT: Behavior Driven Development-based Metamorphic Testing for Autonomous Driving Models\nYear: 2021\n\nAbstract: Deep Neural Network based models are widely used for perception and control in autonomous driving. Recent work leverages metamorphic testing to improve defect detection but is limited to using only an equality-based metamorphic relation. Thus, it does not provide sufficient expressiveness for users to define custom metamorphic relations nor means to automatically generate meaningful inputs based o...","Title: Follow-up Test Cases are Better Than Source Test Cases in Metamorphic Testing: A Preliminary Study\nYear: 2021\n\nAbstract: Recently, metamorphic testing (MT) has been used to augment test datasets by inclusion of new (follow-up) test cases constructed from existing (source) test cases using metamorphic relations (MRs). It has been reported that the augmented test datasets usually have higher fault detection capabilities. It is natural to ask which contributes to the improvement of the fault detection capabilities. To ...","Title: METRIC $^{+}$ + : A Metamorphic Relation Identification Technique Based on Input Plus Output Domains\nYear: 2021\n\nAbstract: Metamorphic testing is well known for its ability to alleviate the oracle problem in software testing. The main idea of metamorphic testing is to test a software system by checking whether each identified metamorphic relation (MR) holds among several executions. In this regard, identifying MRs is an essential task in metamorphic testing. In view of the importance of this identification task, METRI...","Title: Metamorphic Testing of Fake News Detection Software\nYear: 2021\n\nAbstract: Since the popularization of social media, news has entered our lives digitally. While news is spreading broader and faster, fake news is becoming an increasingly popular topic. Fake news detection is therefore important in both social media and research areas. With artificial intelligence technology, software engineers have developed a lot of fake news detection systems. One of the biggest challenges for such systems is that they may face the oracle problem, which means that there may not be a way, or it may take too long time, to confirm the correctness of a specific output. Metamorphic Testing has been applied successfully to alleviate the oracle problem in many different areas, including in artificial intelligence. In this paper, we propose several metamorphic relations for fake news detection and report on experiments using metamorphic testing on fake news detection applications.","Title: Metamorphic Testing for Block Ciphers\nYear: 2021\n\nAbstract: Information is indispensable in modern society. People's daily communication and work depend on information transmission. Unsafe storage or transmission of data may result in privacy and security problems. One way to attempt to prevent such issues is to use encryption algorithms to transform information into encrypted forms. Because the encryption steps of most encryption algorithms are complex, deciding the correctness of the encrypted output may take a long time in practice. This kind of problem is called the Test Oracle problem. In contrast to traditional software testing, Metamorphic Testing (MT) does not focus on the correctness of each individual output, but examines whether the inputs and outputs of multiple executions of a Program Under Test (PUT) satisfy necessary relations of the PUT, called metamorphic relations. This paper reports on an experience of applying MT to test three encryption algorithms - Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), and Advanced Encryption Standard (AES).","Title: Mtkeras: An Automated Metamorphic Testing Platform\nYear: 2021\n\nAbstract: This paper presents an automated, domain-independent, metamorphic testing platform called MTKeras. In this paper, we report on an investigation demonstrating the effectiveness and usability of MTKeras through five case studies in the four domains of image classification, sentiment analysis, search engines and database management systems. We also report on the effectiveness of combining metamorphic relation (input) patterns in individual metamorphic relations, enhancing the failure-finding abilities of the individual relations. The results of our experiments support combining patterns, and the use of MTKeras. The research reported in this paper shows the applicability of metamorphic relation patterns, and introduces a practical tool for the research community.","Title: Metamorphic testing on multi-module UAV systems\nYear: 2021\n\nAbstract: BSTRACTRecent years have seen a rapid development of machine learning based multi-module unmanned aerial vehicle (UAV) systems. To address the oracle problem in autonomous systems, numerous studies have been conducted to use meta-morphic testing to automatically generate test scenes for various modules, e.g., those in self-driving cars. However, as most of the studies are based on unit testing including end-to-end model-based testing, a similar testing approach may not be equally effective for UAV systems where multiple modules are working closely together. Therefore, in this paper, instead of unit testing, we propose a novel metamorphic system testing framework for UAV, named MSTU, to detect the defects in multi-module UAV systems. A preliminary evaluation plan to apply MSTU on an emerging autonomous multi-module UAV system is also presented to demonstrate the feasibility of the proposed testing framework.","Title: Dynamic Random Testing of Web Services: A Methodology and Evaluation\nYear: 2022\n\nAbstract: In recent years, service oriented architecture (SOA) has been increasingly adopted to develop distributed applications in the context of the Internet. To develop reliable SOA-based applications, an important issue is how to ensure the quality of web services. In this article, we propose a dynamic random testing (DRT) technique for web services, which is an improvement over the widely-practiced ran...","Title: MMFC-ART: a Fixed-size-Candidate-set Adaptive Random Testing approach based on the modified Metric-Memory tree\nYear: 2020\n\nAbstract: Adaptive random testing (ART) improves the failure-detection effectiveness of Random testing (RT) by making test cases more evenly distributed in the input domain. The Fixed-size-Candidate-set ART (FSCS-ART) is one of the most classical algorithms, which selects the candidate test case furthest from the previously executed test case as the next test case. However, when the number of executed test ...","Title: Testing Ocean Software with Metamorphic Testing\nYear: 2022\n\nAbstract: Advancing ocean science has a significant impact to the development of the world, from operating a safe navigation for vessels to maintaining a healthy and diverse ocean ecosystem. Various ocean software systems have been extensively adopted for differ-ent purposes, for instance, predicting hourly sea level elevation across shorelines, simulating large-scale ocean circulations, as well as integrating into Earth system models for weather forecasts and climate projections. Regardless of their significance, guaranteeing the trustworthiness of ocean software and modelling systems is a long-standing challenge. The testing of ocean software suffers a lot from the socalled oracle problem, which refers to the absence of test oracles mainly due to the nonlinear interactions of multiple physical variables and the high complexity in computation. In the ocean, observed tidal signals are distorted by non-deterministic physical variables, hindering us from knowing the “true” astronom-ical tidal constituents existing in the timeseries. In this paper, we present how to test tidal analysis and prediction (TAP) software based on metamorphic testing (MT), a simple yet effective testing approach to the oracle problem. In particular, we construct meta-morphic relations from the periodic property of astronomical tide, and then use them to successfully detect a real-life defect in an open-source TAP software. We also conduct a series of experiments to further demonstrate the applicability and effectiveness of MT in the testing of TAP software. Our study not only justifies the poten-tial of MT in testing more complex ocean software and modelling systems, but also can be expanded to assess and improve the quality of a broader range of scientific simulation software systems.","Title: On the effectiveness of testing sentiment analysis systems with metamorphic testing\nYear: 2022\n\nAbstract: •An analysis of false satisfactions, revealing their impacts on metamorphic testing.•An application of metamorphic testing to sentiment analysis systems.•A discussion about the causes for high occurrence rates of false satisfactions.","Title: An Extended Abstract of “Dynamic Random Testing of Web Services: A Methodology and Evaluation”\nYear: 2022\n\nAbstract: [J1C2 Presentation Abstract at IEEE SERVICES 2022 for IEEE Transactions on Services Computing, 2022, 15(2):736-751. DOI: 10.1109/TSC.2019.2960496].","Title: In-Place Metamorphic Testing and Exploration\nYear: 2022\n\nAbstract: In this paper, we consider the testing of software whose input involves a data stream, such as in video analysis applications. To address the oracle problem in testing this kind of software, existing metamorphic testing (MT) and metamorphic exploration (ME) techniques typically generate both source and follow-up input streams. In contrast, we propose a different strategy: an inplace method. Instead of examining relations among multiple input streams, our method works on a finer granularity by investigating relations among the data frames within a single input stream - such as the relations among the image frames within a video stream - treating a frame, rather than a stream, as a test case. Because our method does not generate any follow-up input stream, or change any frame values, it is also suitable for runtime error detection. We have applied this in-place method to testing video streams in Baidu Apollo, a real-life autonomous driving system. Our study identified previously-unknown obstacle perception failures in the camera perception module, including both undetected and incorrectly-detected objects. The empirical results show that our approach is practical, and readily applicable to industrial-scale systems that include (but are not limited to) the computer vision domain.","Title: Using Metamorphic Relation Violation Regions to Support a Simulation Framework for the Process of Metamorphic Testing\nYear: 2022\n\nAbstract: Metamorphic testing (MT) has been growing in popularity, but it can still be quite challenging and time-consuming to assess its performance. Typical approaches to performance assessment can require a series of steps, and depend on a variety of factors, often requiring serendipity. This can be a bottleneck for some aspects of MT research. Central to MT, metamorphic relations (MRs) represent necessary properties of the system under test (SUT). In traditional software testing, simulations are often employed to examine and compare the performance of different testing strategies. However, these simulations are typically designed based on the assumed availability (and applicability) of a test oracle - a mechanism to decide the correctness of the SUT output or behaviour. A key reason for the popularity of MT is its proven record of effective software testing, without the need for a test oracle. This strength, however, also means that traditional ways of using simulations to analyse software testing approaches are not applicable for MT. This lack of cheap and fast ways to conduct simulation analyses of MT is a hurdle for many aspects of MT research, and may be an obstacle to its more widespread adoption. To address this, in this paper we introduce the concept of MR-violation regions (MRVRs), and show how they can be used for a certain category of MRs, Deterministic MRs (DMRs), to build simulation tools for MT. We analyse the differences between MRVRs and traditional, oracle-defined failure regions; and report on a preliminary case study exploring MRVRs in numerical-input-domain systems from previous MT studies. We anticipate that the proposed MT simulation framework may facilitate more research into MT, and may help lead to its more widespread adoption."],"string":"[\n \"Title: Adaptive Random Testing\\nYear: 2004\\n\\nAbstract: In this paper, we introduce an enhanced form of random testing called Adaptive Random Testing. Adaptive random testing seeks to distribute test cases more evenly within the input space. It is based on the intuition\\n that for non-point types of failure patterns, an even spread of test cases is more likely to detect failures using fewer test\\n cases than ordinary random testing. Experiments are performed using published programs. Results show that adaptive random\\n testing does outperform ordinary random testing significantly (by up to as much as 50%) for the set of programs under study.\\n These results are very encouraging, providing evidences that our intuition is likely to be useful in improving the effectiveness\\n of random testing.\",\n \"Title: Good Random Testing\\nYear: 2004\\n\\nAbstract: Software Testing is recognized as an essential part of the Software Development process. Random Testing (RT), the selection of test cases at random from the input domain, is a simple and efficient method of Software Testing. Previous research has indicated that, under certain circumstances, the performance of RT can be improved by enforcing a more even, well-spread distribution of test cases over the input domain. Test cases that contribute to this goal can be considered 'good,' and are more desirable when choosing potential test cases than those that do not contribute. Fuzzy Set Theory enables a calculation of the degree of membership of the set of 'good' test cases for any potential test case, in other words, a calculation of how 'good' the test case is. This paper presents research in the area of improving on the failure finding efficiency of RT using Fuzzy Set Theory. An approach is proposed and evaluated according to simulation results and comparison with other testing methods.\",\n \"Title: Restricted Random Testing\\nYear: 2002\\n\\nAbstract: This paper presents a novel adaptation of traditional random testing, called Restricted Random Testing (RRT). RRT offers a\\n significant improvement over random testing, as measured by the F-measure. This paper describes the ideology behind RRT and\\n explains its algorithm. RRT’s performance is examined using several experiments, the results of which are presented and discussed.\",\n \"Title: Metamorphic Testing: A Simple Approach to Alleviate the Oracle Problem\\nYear: 2010\\n\\nAbstract: The oracle problem is very common in the testing of service-oriented systems. Metamorphic testing has been proposed to alleviate the oracle problem in software testing. This talk aims at presenting the state of the art in metamorphic testing. It summaries what testing techniques have been successfully integrated with metamorphic testing and what application areas metamorphic testing have been applied to successfully alleviate the oracle problem. It will also introduce potential research projects using the metamorphic approach.\",\n \"Title: Comparison of adaptive random testing and random testing under various testing and debugging scenarios\\nYear: 2012\\n\\nAbstract: Adaptive random testing is an enhancement of random testing. Previous studies on adaptive random testing assumed that once a failure is detected, testing is terminated and debugging is conducted immediately. It has been shown that adaptive random testing normally uses fewer test cases than random testing for detecting the first software failure. However, under many practical situations, testing should not be withheld after the detection of a failure. Thus, it is important to investigate the effectiveness with respect to the detection of multiple failures. In this paper, we compare adaptive random testing and random testing under various scenarios and examine whether adaptive random testing is still able to use fewer test cases than random testing to detect multiple software failures. Our study delivers some interesting results and highlights a number of promising research projects. Copyright © 2011 John Wiley & Sons, Ltd.\",\n \"Title: Distribution-Aware Mutation Analysis\\nYear: 2012\\n\\nAbstract: Mutation analysis is widely employed to evaluate the effectiveness of various software testing techniques. In most situations, mutation operators are uniformly applied to the original programs, while the faults tend to be clustered in practice. This may result in the inappropriate simulation of faults, and thus cannot deliver the reliable evaluation results. To overcome this, we propose a distribution-aware mutation analysis technique and conducted empirical studies to investigate the impact of the mutation distribution on the effectiveness evaluation of testing techniques. As an illustration, we select the commonly practiced random testing technique and two versions of dynamic random testing techniques and apply them to testing Web services. Results of empirical studies suggest that the mutation distribution significantly affects the evaluation results. This observation further indicates that the effectiveness of testing techniques previously evaluated with the uniform mutation analysis needs further realignments.\",\n \"Title: Metamorphic Testing and Beyond\\nYear: 2003\\n\\nAbstract: When testing a program, correctly executed test cases are seldom explored further, even though they may carry useful information. Metamorphic testing proposes to generate follow-up test cases to check important properties of the target function. It does not need a human oracle for output prediction and comparison. In this paper, we highlight the basic concepts of metamorphic testing and some interesting extensions in the areas of program testing, proving, and debugging. Future research directions are also proposed.\",\n \"Title: Normalized restricted random testing\\nYear: 2003\\n\\nAbstract: Restricted Random Testing (RRT) is a new method of testing software that improves upon traditional random testing (RT) techniques. This paper presents new data in support of the efficiency of RRT, and presents a variation of the algorithm, Normalized Restricted Random Testing (NRRT). NRRT permits the tester to have better information about the target exclusion rate (R) of RRT, the main control parameter of the method. We examine the performance of the NRRT and Original RRT (ORRT) methods using simulations and experiments, and offer some guidance for their use in practice.\",\n \"Title: Metamorphic Testing and Testing with Special Values\\nYear: 2004\\n\\nAbstract: The problem of testing programs without test oracles is well known. A commonly used approach is to use special values in testing but this is often insufficient to ensure program correctness. This paper demonstrates the use of metamorphic testing to uncover faults in programs, which could not be detected by special test values. Metamorphic testing can be used as a complementary test method to special value testing. In this paper, the sine function and a search function are used as examples to demonstrate the usefulness of metamorphic testing. This paper also examines metamorphic relationships and the extent of their usefulness in program testing.\",\n \"Title: DESSERT: a DividE-and-conquer methodology for identifying categorieS, choiceS, and choicE Relations for Test case generation\\nYear: 2012\\n\\nAbstract: This paper extends the choce relation framework, abbreviated as choc'late, which assists software testers in the application of category/choice methods to testing. choc'late assumes that the tester is able to construct a single choice relation table from the entire specification; this table then forms the basis for test case generation using the associated algorithms. This assumption, however, may not hold true when the specification is complex and contains many specification components. For such a specification, the tester may construct a preliminary choice relation table from each specification component, and then consolidate all the preliminary tables into a final table to be processed by choc'late for test case generation. However, it is often difficult to merge these preliminary tables because such merging may give rise to inconsistencies among choice relations or overlaps among choices. To alleviate this problem, we introduce a DividE-and-conquer methodology for identifying categorieS, choiceS, and choicE Relations for Test case generation, abbreviated as dessert. The theoretical framework and the associated algorithms are discussed. To demonstrate the viability and effectiveness of our methodology, we describe case studies using the specifications of three real-life commercial software systems.\",\n \"Title: Spectrum-Based Fault Localization: Testing Oracles are No Longer Mandatory\\nYear: 2011\\n\\nAbstract: Spectrum-based Fault Localization (SBFL) is one of the most popular approaches for locating software faults, and has received much attention because of its simplicity and effectiveness. It utilizes the execution result of each test case (failure or pass) and the corresponding coverage information to evaluate the likelihood of each program entity (e.g., a statement or a predicate) being faulty. Different formulas for computing such likelihood have been proposed based on different intuitions. All existing SBFL techniques have assumed the existence of a testing oracle, that is, a mechanism which can determine whether the execution of a test case fails or passes. However, such an assumption does not always hold. Recently, metamorphic testing has been proposed to alleviate the oracle problem. Thus, it is a natural extension to investigate how it can help SBFL techniques to locate faults even without using a testing oracle. Based on the framework of metamorphic testing, we have developed a novel concept of mice as a counterpart of the slice used in the current SBFL techniques. More precisely, in the absence of a testing oracle, we can determine whether an expected characterization of the program is satisfied. The outcomes of dissatisfaction or satisfaction of an expected characterization are then regarded as the counterparts of failed or passed executions, respectively, when a testing oracle exists. Since our approach does not require the existence of a testing oracle, it significantly enhances the applicability of SBFL techniques. Case studies on three popular SBFL techniques (Tarantula, Ochiai and Jaccard) with 9 applications are reported to demonstrate the use of the proposed fault localization technique.\",\n \"Title: An upper bound on software testing effectiveness\\nYear: 2008\\n\\nAbstract: Failure patterns describe typical ways in which inputs revealing program failure are distributed across the input domain—in many cases, clustered together in contiguous regions. Based on these observations several debug testing methods have been developed. We examine the upper bound of debug testing effectiveness improvements possible through making assumptions about the shape, size and orientation of failure patterns. We consider the bounds for testing strategies with respect to minimizing the F-measure, maximizing the P-measure, and maximizing the E-measure. Surprisingly, we find that the empirically measured effectiveness of some existing methods that are not based on these assumptions is close to the theoretical upper bound of these strategies. The assumptions made to obtain the upper bound, and its further implications, are also examined.\",\n \"Title: Adaptive Random Testing by Exclusion through Test Profile\\nYear: 2010\\n\\nAbstract: One major objective of software testing is to reveal software failures such that program bugs can be removed. Random testing is a basic and simple software testing technique, but its failure-detection effectiveness is often controversial. Based on the common observation that program inputs causing software failures tend to cluster into contiguous regions, some researchers have proposed that an even spread of test cases should enhance the failure-detection effectiveness of random testing. Adaptive random testing refers to a family of algorithms to evenly spread random test cases based on various notions. Restricted random testing, an algorithm to implement adaptive random testing by the notion of exclusion, defines an exclusion region around each previously executed test case, and selects test cases only from outside all exclusion regions. Although having a high failure-detection effectiveness, restricted random testing has a very high computation overhead, and it rigidly discards all test cases inside any exclusion region, some of which may reveal software failures. In this paper, we propose a new method to implement adaptive random testing by exclusion, where test cases are simply selected based on a well-designed test profile. The new method has a low computation overhead and it does not omit any possible program inputs that can detect failures. Our experimental results show that the new method not only spreads test cases more evenly but also brings a higher failure-detection effectiveness than random testing.\",\n \"Title: A New Method for Constructing Metamorphic Relations\\nYear: 2012\\n\\nAbstract: A fundamental problem for software testing is the oracle problem, which means that in many practical situations, it is extremely expensive, if not impossible, to verify the test result given any possible program input. Metamorphic testing is an approach to alleviating the oracle problem. The key part of metamorphic testing is a set of necessary properties of the software under test, namely metamorphic relations. Metamorphic relations not only help generate test cases, but also provide a mechanism to partially verify the test results without the need of oracle. In most previous studies, metamorphic relations were identified manually by testers in an ad hoc way. There is no systematic methodology that helps us identify metamorphic relations. In this paper, we propose a simple method, namely, the composition of metamorphic relations, for systematically constructing new metamorphic relations based on the already identified metamorphic relations. We conduct a case study and show that new metamorphic relations can be easily constructed by compositing some existing metamorphic relations. It is also observed that the new metamorphic relations are very likely to deliver a higher cost-effectiveness of metamorphic testing than the original metamorphic relations.\",\n \"Title: Adaptive Random Test Case Generation for Combinatorial Testing\\nYear: 2012\\n\\nAbstract: Random testing (RT), a fundamental software testing technique, has been widely used in practice. Adaptive random testing (ART), an enhancement of RT, performs better than original RT in terms of fault detection capability. However, not much work has been done on effectiveness analysis of ART in the combinatorial test spaces. In this paper, we propose a novel family of ART-based algorithms for generating combinatorial test suites, mainly based on fixed-size-candidate-set ART and restricted random testing (that is, ART by exclusion). We use an empirical approach to compare the effectiveness of test sets obtained by our proposed methods and random selection strategy. Experimental data demonstrate that the ART-based tests cover all possible combinations at a given strength more quickly than randomly chosen tests, and often detect more failures earlier and with fewer test cases in simulations.\",\n \"Title: An Analysis of Failure-Based Test Profiles for Random Testing\\nYear: 2011\\n\\nAbstract: In random testing, the distribution of the generated test cases is known as the test profile. We consider the effects of different test profiles, taking advantage of probabilistic information about likely failure-revealing inputs, on the effectiveness of random testing for debugging. We examine a failure-proportional testing strategy, in which tests are randomly sampled with replacement, with probability proportional to a previously identified failure probability distribution, compared to a uniform testing strategy, in which tests are randomly sampled uniformly from the entire input domain. We show that neither strategy optimises failure-detection capabilities, and show an alternative strategy that does. We also consider selection without replacement, and examine the robustness of some strategies given a divergence between the estimated and actual failure probability distributions.\",\n \"Title: Incremental Identification of Categories and Choices for Test Case Generation: A Study of the Software Practitioners' Preferences\\nYear: 2013\\n\\nAbstract: Test case generation is a vital procedure in the engineering of test harnesses. In particular, the choice relation framework and the category-partition method play an important role, by requiring software testers to identify categories (intuitively equivalent to input parameters or environment conditions) and choices (intuitively equivalent to ranges of values) from a specification and to systematically work on the identified choices to generate test cases. Other specification-based test case generation methods (such as the classification-tree method, cause-effect graphing, and combinatorial testing) also have similar requirements, although different terminology such as classifications and classes is used in place of categories and choices. For a large and complex specification that contains many specification components, categories and choices may be identified separately from various kinds of components. We call this practice an incremental identification approach. In this paper, we discuss our study involving 16 experienced software practitioners and three commercial specifications. Our objectives are to determine, from the opinions of the practitioners, (a) the popularity of an incremental identification approach, (b) the usefulness of identifying categories and choices from various kinds of specification components, and (c) possible ways to improve the effectiveness of the identification process.\",\n \"Title: Application of a Failure Driven Test Profile in Random Testing\\nYear: 2009\\n\\nAbstract: Random testing techniques have been extensively used in reliability assessment, as well as in debug testing. When used to assess software reliability, random testing selects test cases based on an operational profile; while in the context of debug testing, random testing often uses a uniform distribution. However, generally neither an operational profile nor a uniform distribution is chosen from t...\",\n \"Title: Adaptive random testing based on distribution metrics\\nYear: 2009\\n\\nAbstract: Random testing (RT) is a fundamental software testing technique. Adaptive random testing (ART), an enhancement of RT, generally uses fewer test cases than RT to detect the first failure. ART generates test cases in a random manner, together with additional test case selection criteria to enforce that the executed test cases are evenly spread over the input domain. Some studies have been conducted to measure how evenly an ART algorithm can spread its test cases with respect to some distribution metrics. These studies observed that there exists a correlation between the failure detection capability and the evenness of test case distribution. Inspired by this observation, we aim to study whether failure detection capability of ART can be enhanced by using distribution metrics as criteria for the test case selection process. Our simulations and empirical results show that the newly proposed algorithms not only improve the evenness of test case distribution, but also enhance the failure detection capability of ART.\",\n \"Title: Adaptive random testing through iterative partitioning revisited\\nYear: 2006\\n\\nAbstract: Recently, Adaptive Random Testing through Iterative Partitioning (IP-ART) has been proposed as a random testing method that is more effective than pure Random Testing. Besides this, it is supposed to be equally effective as very good random testing techniques, namely Distance-Based Adaptive Random Testing and Restricted Random Testing, while only having between linear and quadratic runtime. In the present paper, it is investigated what influence the ratio of width and height of a rectangular input domain has on the effectiveness of various Adaptive Random Testing methods. Based on our findings, an improved version of IP-ART is proposed. The effectiveness of the new method is also analyzed for various ratios of width and height of the input domain.\",\n \"Title: Restricted Random Testing: Adaptive Random Testing By Exclusion\\nYear: 2006\\n\\nAbstract: Restricted Random Testing (RRT) is a new method of testing software that improves upon traditional Random Testing (RT) techniques. Research has indicated that failure patterns (portions of an input domain which, when executed, cause the program to fail or reveal an error) can influence the effectiveness of testing strategies. For certain types of failure patterns, it has been found that a widespread and even distribution of test cases in the input domain can be significantly more effective at detecting failure compared with ordinary RT. Testing methods based on RT, but which aim to achieve even and widespread distributions, have been called Adaptive Random Testing (ART) strategies. One implementation of ART is RRT. RRT uses exclusion zones around executed, but non-failure-causing, test cases to restrict the regions of the input domain from which subsequent test cases may be drawn. In this paper, we introduce the motivation behind RRT, explain the algorithm and detail some empirical analyses carried out to examine the effectiveness of the method. Two versions of RRT are presented: Ordinary RRT (ORRT) and Normalized RRT (NRRT). The two versions share the same fundamental algorithm, but differ in their treatment of non-homogeneous input domains. Investigations into the use of alternative exclusion shapes are outlined, and a simple technique for reducing the computational overheads of RRT, prompted by the alternative exclusion shape investigations, is also explained. The performance of RRT is compared with RT and another ART method based on maximized minimum test case separation (DART), showing excellent improvement over RT and a very favorable comparison with DART.\",\n \"Title: An Innovative Approach to Randomising Quasi-random Sequences and Its Application into Software Testing\\nYear: 2009\\n\\nAbstract: Quasi-random sequences, which can evenly spread points across a hypercube, have been widely used in various areas. Recently, quasi-random testing technique, which makes use of quasi-random sequences to generate test cases, was proposed, and it normally has a higher failure-detection capability than pure random testing. However, there exist only a few distinct quasi-random sequences in the literature, and all these sequences are deterministic rather than random. Therefore, the applicability of quasi-random sequences in testing is restricted. In this paper, we propose a new approach to randomising quasi-random sequences. Out approach can generate many distinct randomised quasi-random sequences that have even distributions of points. The experimental results also show that these sequences can significantly enhance the effectiveness of random testing.\",\n \"Title: A New Perspective of the Proportional Sampling Strategy\\nYear: 1999\\n\\nAbstract: To compare the performance of different testing strategies, P-measure and E-measure are two effectiveness measures used in previous analytical studies. P-measure, which is defined as the probability of detecting at least one failure, is a measure of how likely it is that failure-causing inputs are selected at least once as test cases. E-measure, which is defined as the expected number of failures ...\",\n \"Title: On the statistical properties of testing effectiveness measures\\nYear: 2006\\n\\nAbstract: We examine the statistical variability of three commonly used software testing effectiveness measures-the E-measure (expected number of failures detected), P-measure (probability of detecting at least one failure), and F-measure (number of tests required to detect the first failure). We show that for random testing with replacement, the F-measure will be distributed according to the geometric distribution. A simulation study examines the distribution of two adaptive random testing methods, to investigate how closely their sampling distributions approximate the geometric distribution. One key observation is that in the worst case scenario, the sampling distribution of adaptive random testing is very similar to that of random testing. The E-measure and P-measure have a normal sampling distribution, but high variability, meaning that large sample sizes are required to obtain results with satisfactorily narrow confidence intervals. We illustrate this with a simulation study for the P-measure. Our results have reinforced, from a perspective other than empirical analysis, that adaptive random testing is a more effective alternative to random testing, with reference to the F-measure. We consider the implications of our findings for previous studies conducted in the area, and make recommendations to future studies.\",\n \"Title: On the statistical properties of the F-measure\\nYear: 2004\\n\\nAbstract: The F-measure - the number of distinct test cases to detect the first program failure - is an effectiveness measure for debug testing strategies. We show that for random testing with replacement, the F-measure is distributed according to the geometric distribution. A simulation study examines the distribution of two adaptive random testing methods, to study how closely their sampling distributions approximate the geometric distribution, revealing that in the worst case scenario, the sampling distribution for adaptive random testing is very similar to random testing. Our results have provided an answer to a conjecture that adaptive random testing is always a more effective alternative to random testing, with reference to the F-measure. We consider the implications of our findings for previous studies conducted in the area, and make recommendations to future studies.\",\n \"Title: On the maximin algorithms for test allocations in partition testing\\nYear: 2001\\n\\nAbstract: The proportional sampling (PS) strategy is a partition testing strategy that has been proved to have a better chance than random testing to detect at least one failure. A near proportional sampling (NPS) strategy is one that approximates the PS strategy when the latter is not feasible. We have earlier proved that the (basic) maximin algorithm generates a maximin test allocation, that is, an allocation of test cases that will maximally improve the lower bound performance of the partition testing strategy, and shown that the algorithm may serve as a systematic means of approximating the PS strategy. In this paper, we derive the uniqueness and completeness conditions of generating maximin test allocations, propose the complete maximin algorithm that generates all possible maximin test allocations and demonstrate empirically that the new algorithm is consistently better than random testing as well as several other NPS strategies.\",\n \"Title: Testing an Open Source Suite for Open Queuing Network Modelling Using Metamorphic Testing Technique\\nYear: 2009\\n\\nAbstract: Queuing network modelling is a modelling technique for capacity planning studies of computer and communication systems. Due to complexity of the technique, it is very difficult to know from the computed outputs whether the computation of the modelling software is correct. It is necessary to have an effective testing technique to address this problem. Recently, it has been noticed that metamorphic testing is an effective technique for this kind of problem. In this paper, we study the technique of metamorphic testing in testing queuing network modelling through a set of testing experiments in the Java Modelling Tool – a popular open source queuing network modelling suite.\",\n \"Title: On Favourable Conditions For Adaptive Random Testing\\nYear: 2007\\n\\nAbstract: Recently, adaptive random testing ( ART) has been developed to enhance the fault-detection effectiveness of random testing (RT). It has been known in general that the fault-detection effectiveness of ART depends on the distribution of failure-causing inputs, yet this understanding is in coarse terms without precise details. In this paper, we conduct an in-depth investigation into the factors related to the distribution of failure-causing inputs that have an impact on the fault-detection effectiveness of ART. This paper gives a comprehensive analysis of the favourable conditions for ART. Our study contributes to the knowledge of ART and provides useful information for testers to decide when it is more cost-effective to use ART.\",\n \"Title: On the Minimal Essential Subsets and Minimal Representative Sets\\nYear: 2000\\n\\nAbstract: Test suite reduction aims at generating representative sets defined as subsets of a test suite that satisfy the same test\\n objective. There are various types of representative sets. Those representative sets without redundancy are referred to as\\n the minimal representative sets. A subset of the test suite is referred to as essential if the remaining test cases cannot\\n collectively satisfy the same test objective when the subset is removed from the test suite. This paper studies the relationships\\n between the set of minimal representative sets and the set of essential subsets.\",\n \"Title: Backward-Slice-Based Statistical Fault Localization without Test Oracles\\nYear: 2013\\n\\nAbstract: A recent promising technique for fault localization, Backward-Slice-based Statistical Fault Localization (BSSFL), statistically analyzes the backward slices and results of a set of test cases to evaluate the suspiciousness of a statement being faulty. However, BSSFL like many existing fault localization approaches assumes the existence of a test oracle to determine whether the result of a test case is a failure or pass. In reality, test oracles do not always exist, and therefore in such cases BSSFL can be severely infeasible. Among current research, metamorphic testing has been widely studied as a technique to alleviate the oracle problem. Hence, we leverage metamorphic testing to conduct BSSFL without test oracles. With metamorphic testing, our approach uses the backward slices and the metamorphic result of violation or non-violation for a metamorphic test group, rather than the backward slice and the result of failure or pass for an individual test case in BSSFL. Because our approach does not need the execution result of a test case, it implies that BSSFL can be extended to those application domains where no test oracle exists. The experimental results on 8 programs and 2 groups of the maximal suspiciousness evaluation formulas show that our proposed approach demonstrates the effectiveness comparable to that of existing BSSFL techniques in the cases where test oracles exist.\",\n \"Title: Test Suite Reduction and Fault Detecting Effectiveness: An Empirical Evaluation\\nYear: 2001\\n\\nAbstract: Test suite reduction is aimed at finding representative sets that can satisfy the same testing objective as their original test suite. As a subset of the original test suite, the representative set may have less fault detection capability. However, researches show that a representative set and its original test suite have similar fault detection capabilities for the case of coverage based criteria. This paper investigates the relationship between the fault detection capabilities of a representative set and its original test suite when the generation of the test suite is based on some fault-based test case selection criteria.\",\n \"Title: Integration Testing Of Context-Sensitive Middleware-Based Applications: A Metamorphic Approach\\nYear: 2006\\n\\nAbstract: During the testing of context-sensitive middleware-based software, the middleware checks the current situation to invoke the appropriate functions of the applications. Since the middleware remains active and the situation may continue to evolve, however, the conclusion of some test cases may not easily be identified. Moreover, failures appearing in one situation may be superseded by subsequent correct outcomes and, therefore, be hidden.We alleviate the above problems by making use of a special kind of situation, which we call checkpoints, such that the middleware will not activate the functions under test. We recommend testers to generate test cases that start at a checkpoint and end at another. Testers may identify relations that associate different execution sequences of a test case. They then check the results of each test case to detect any contravention of such relations. We illustrate our technique with an example that shows how hidden failures can be detected. We also report the experimentation carried out on an RFID-based location-sensing application on top of a context-sensitive middleware.\",\n \"Title: Code Coverage of Adaptive Random Testing\\nYear: 2013\\n\\nAbstract: Random testing is a basic software testing technique that can be used to assess the software reliability as well as to detect software failures. Adaptive random testing has been proposed to enhance the failure-detection capability of random testing. Previous studies have shown that adaptive random testing can use fewer test cases than random testing to detect the first software failure. In this paper, we evaluate and compare the performance of adaptive random testing and random testing from another perspective, that of code coverage. As shown in various investigations, a higher code coverage not only brings a higher failure-detection capability, but also improves the effectiveness of software reliability estimation. We conduct a series of experiments based on two categories of code coverage criteria: structure-based coverage, and fault-based coverage. Adaptive random testing can achieve higher code coverage than random testing with the same number of test cases. Our experimental results imply that, in addition to having a better failure-detection capability than random testing, adaptive random testing also delivers a higher effectiveness in assessing software reliability, and a higher confidence in the reliability of the software under test even when no failure is detected.\",\n \"Title: Does Adaptive Random Testing Deliver a Higher Confidence than Random Testing?\\nYear: 2008\\n\\nAbstract: Random testing (RT) is a fundamental software testing technique. Motivated by the rationale that neighbouring test cases tend to cause similar execution behaviours, adaptive random testing (ART) was proposed as an enhancement of RT, which enforces random test cases evenly spread over the input domain. ART has always been compared with RT from the perspective of the failure-detection capability. Previous studies have shown that ART can use fewer test cases to detect the first software failure than RT. In this paper, we aim to compare ART and RT from the perspective of program-based coverage. Our experimental results show that given the same number of test cases, ART normally has a higher percentage of coverage than RT. In conclusion, ART outperforms RT not only in terms of the failure-detection capability, but also in terms of the thoroughness of program-based coverage. Therefore, ART delivers a higher confidence of the software under test than RT even when no failure has been revealed.\",\n \"Title: The ART of Divide and Conquer: An Innovative Approach to Improving the Efficiency of Adaptive Random Testing\\nYear: 2013\\n\\nAbstract: Test case selection is a prime process in the engineering of test harnesses. In particular, test case diversity is an important concept. In order to achieve an even spread of test cases across the input domain, Adaptive Random Testing (ART) was proposed such that the history of previously executed test cases are taken into consideration when selecting the next test case. This was achieved through various means such as best candidate selection, exclusion, partitioning, and diversity metrics. Empirical studies showed that ART algorithms make good use of the concept of even spreading and achieve 40 to 50% improvement in test effectiveness over random testing in revealing the first failure, which is close to the theoretical limit. However, the computational complexity of ART algorithms may be quadratic or higher, and hence efficiency is an issue when a large number of previously executed test cases are involved. This paper proposes an innovative divide-and-conquer approach to improve the efficiency of ART algorithms while maintaining their performance in effectiveness. Simulation studies have been conducted to gauge its efficiency against two most commonly used ART algorithms, namely, fixed size candidate set and restricted random testing. Initial experimental results show that the divide-and-conquer technique can provide much better efficiency while maintaining similar, or even better, effectiveness.\",\n \"Title: How Effectively Does Metamorphic Testing Alleviate the Oracle Problem?\\nYear: 2014\\n\\nAbstract: In software testing, something which can verify the correctness of test case execution results is called an oracle. The oracle problem occurs when either an oracle does not exist, or exists but is too expensive to be used. Metamorphic testing is a testing approach which uses metamorphic relations, properties of the software under test represented in the form of relations among inputs and outputs of multiple executions, to help verify the correctness of a program. This paper presents new empirical evidence to support this approach, which has been used to alleviate the oracle problem in various applications and to enhance several software analysis and testing techniques. It has been observed that identification of a sufficient number of appropriate metamorphic relations for testing, even by inexperienced testers, was possible with a very small amount of training. Furthermore, the cost-effectiveness of the approach could be enhanced through the use of more diverse metamorphic relations. The empirical studies presented in this paper clearly show that a small number of diverse metamorphic relations, even those identified in an ad hoc manner, had a similar fault-detection capability to a test oracle, and could thus effectively help alleviate the oracle problem.\",\n \"Title: On the fixpoints of nondeterministic recursive definitions\\nYear: 1984\\n\\nAbstract: This paper is concerned with the existence and properties of various fixpoints of nondeterministic recursive definitions.\",\n \"Title: On the expected number of failures detected by subdomain testing and random testing\\nYear: 1996\\n\\nAbstract: We investigate the efficacy of subdomain testing and random testing using the expected number of failures detected (the E-measure) as a measure of effectiveness. Simple as it is, the E-measure does provide a great deal of useful information about the fault detecting capability of testing strategies. With the E-measure, we obtain new characterizations of subdomain testing, including several new conditions that determine whether subdomain testing is more or less effective than random testing. Previously, the efficacy of subdomain testing strategies has been analyzed using the probability of detecting at least one failure (the P-measure) for the special case of disjoint subdomains only. On the contrary, our analysis makes use of the E-measure and considers also the general case in which subdomains may or may not overlap. Furthermore, we discover important relations between the two different measures. From these relations, we also derive corresponding characterizations of subdomain testing in terms of the P-measure\",\n \"Title: On the Correlation between the Effectiveness of Metamorphic Relations and Dissimilarities of Test Case Executions\\nYear: 2013\\n\\nAbstract: Metamorphic testing (MT) is a property-based automated software testing method. It alleviates the oracle problem by testing programs against metamorphic relations (MRs), which are necessary properties among multiple executions of the target program. For a given problem, usually more than one MR can be identified. It is therefore of practical importance for testers to know the nature of good MRs, that is, which MRs are likely to have higher chances of revealing failures. To address this issue we investigate the correlation between the fault-detection effectiveness of MRs and the dissimilarity (distance) of test case execution profiles. Empirical study results reveal that there is a strong and statistically significant positive correlation between the fault-detection effectiveness and the distance. The findings of this research can help to develop automated means of selecting/prioritizing MRs for cost-effective metamorphic testing.\",\n \"Title: On the structural properties of the set of fixpoints for nondeterministic recursive definitions\\nYear: 1996\\n\\nAbstract: In this paper, we investigate the structural properties of the set of fixpoints for the class of nondeterministic recursive definitions. Our study reveals close resemblance between the structural properties of the set of fixpoints and those of the set of prefixpoints, and it establishes some equality relationships between various fixpoints and their corresponding prefixpoints. Also observed are some nonequality relationships between various fixpoints and their corresponding postfixpoints.\",\n \"Title: How well does test case prioritization integrate with statistical fault localization?\\nYear: 2012\\n\\nAbstract: Context: Effective test case prioritization shortens the time to detect failures, and yet the use of fewer test cases may compromise the effectiveness of subsequent fault localization. Objective: The paper aims at finding whether several previously identified effectiveness factors of test case prioritization techniques, namely strategy, coverage granularity, and time cost, have observable consequences on the effectiveness of statistical fault localization techniques. Method: This paper uses a controlled experiment to examine these factors. The experiment includes 16 test case prioritization techniques and four statistical fault localization techniques using the Siemens suite of programs as well as grep, gzip, sed, and flex as subjects. The experiment studies the effects of the percentage of code examined to locate faults from these benchmark subjects after a given number of failures have been observed. Results: We find that if testers have a budgetary concern on the number of test cases for regression testing, the use of test case prioritization can save up to 40% of test case executions for commit builds without significantly affecting the effectiveness of fault localization. A statistical fault localization technique using a smaller fraction of a prioritized test suite is found to compromise its effectiveness seriously. Despite the presence of some variations, the inclusion of more failed test cases will generally improve the fault localization effectiveness during the integration process. Interestingly, during the variation periods, adding more failed test cases actually deteriorates the fault localization effectiveness. In terms of strategies, Random is found to be the most effective, followed by the ART and Additional strategies, while the Total strategy is the least effective. We do not observe sufficient empirical evidence to conclude that using different coverage granularity levels have different overall effects. Conclusion: The paper empirically identifies that strategy and time-cost of test case prioritization techniques are key factors affecting the effectiveness of statistical fault localization, while coverage granularity is not a significant factor. It also identifies a mid-range deterioration in fault localization effectiveness when adding more test cases to facilitate debugging.\",\n \"Title: Constraints For Safe Partition Testing Strategies\\nYear: 1996\\n\\nAbstract: Although previous studies have shown that partition testing strategies are not always very effective, with appropriate restrictions on the test allocation they can be guaranteed to be safe, in the sense that they will never be less reliable in detecting at least one failure than random testing, Several sufficient conditions for this have already been established in the literature. In particular, the proportional sampling strategy, which allocates test cases in proportion to the size of the subdomains from which they are selected, has been proved to be safe for all programs. In practice, since the number of test cases must be positive integers, often the proportional sampling strategy can only be approximated. This paper examines the necessary conditions for safe partition testing strategies. We also prove that, when the input domain is large enough with respect to the numbers of failure-causing inputs and test cases, a safe partition testing strategy cannot deviate from the proportional sampling strategy other than rounding due to integral constraints.\",\n \"Title: A revisit of fault class hierarchies in general boolean specifications\\nYear: 2011\\n\\nAbstract: Recently, Kapoor and Bowen [2007] have extended the works by Kuhn [1999], Tsuchiya and Kikuno [2002], and Lau and Yu [2005]. However, their proofs overlook the possibility that a mutant of the Boolean specifications under test may be equivalent. Hence, each of their fault relationships is either incorrect or has an incorrect proof. In this article, we give counterexamples to the incorrect fault relationships and provide new proofs for the valid fault relationships. Furthermore, a co-stronger fault relation is introduced to establish a new fault class hierarchy for general Boolean specifications.\",\n \"Title: Metamorphic fault tolerance: an automated and systematic methodology for fault tolerance in the absence of test oracle\\nYear: 2014\\n\\nAbstract: A system may fail due to an internal bug or a fault in its execution environment. Incorporating fault tolerance strategies enables such system to complete its function despite the failure of some of its parts. Prior to the execution of some fault tolerance strategies, failure detection is needed. Detecting incorrect output, for instance, assumes the existence of an oracle to check the correctness of program outputs given an input. However, in many practical situations, oracle does not exist or is extremely difficult to apply. Such an oracle problem is a major challenge in the context of software testing. In this paper, we propose to apply metamorphic testing, a software testing method that alleviates the oracle problem, into fault tolerance. The proposed technique supports failure detection without the need of oracles.\",\n \"Title: An assessment of systems and software engineering scholars and institutions (2002–2006)\\nYear: 2009\\n\\nAbstract: This paper summarizes a survey of publications in the field of systems and software engineering from 2002 to 2006. The survey is an ongoing, annual event that identifies the top 15 scholars and institutions over a 5-year period. The rankings are calculated based on the number of papers published in TSE, TOSEM, JSS, SPE, EMSE, IST, and Software. The top-ranked institution is Korea Advanced Institute of Science and Technology, Korea, and the top-ranked scholar is Magne Jørgensen of Simula Research Laboratory, Norway.\",\n \"Title: A decision-theoretic approach to the test allocation problem in partition testing\\nYear: 2002\\n\\nAbstract: A partition testing strategy consists of two components: a partitioning scheme which determines the way in which the program's input domain is partitioned into subdomains; and an allocation of test cases which determines the exact number of test cases selected from each subdomain. This paper investigates the problem of determining the test allocation when a particular partitioning scheme has been chosen. We show that this problem can be formulated as a classic problem of decision-making under uncertainty, and analyze several well known criteria to resolve this kind of problem. We present algorithms that solve the test allocation problem based on these criteria, and evaluate these criteria by means of a simulation experiment. We also discuss the applicability and implications of applying these criteria in the context of partition testing.\",\n \"Title: A theoretical analysis of the risk evaluation formulas for spectrum-based fault localization\\nYear: 2013\\n\\nAbstract: An important research area of Spectrum-Based Fault Localization (SBFL) is the effectiveness of risk evaluation formulas. Most previous studies have adopted an empirical approach, which can hardly be considered as sufficiently comprehensive because of the huge number of combinations of various factors in SBFL. Though some studies aimed at overcoming the limitations of the empirical approach, none of them has provided a completely satisfactory solution. Therefore, we provide a theoretical investigation on the effectiveness of risk evaluation formulas. We define two types of relations between formulas, namely, equivalent and better. To identify the relations between formulas, we develop an innovative framework for the theoretical investigation. Our framework is based on the concept that the determinant for the effectiveness of a formula is the number of statements with risk values higher than the risk value of the faulty statement. We group all program statements into three disjoint sets with risk values higher than, equal to, and lower than the risk value of the faulty statement, respectively. For different formulas, the sizes of their sets are compared using the notion of subset. We use this framework to identify the maximal formulas which should be the only formulas to be used in SBFL.\",\n \"Title: Enhancing Adaptive Random Testing through Partitioning by Edge and Centre\\nYear: 2007\\n\\nAbstract: Quality requirements of software systems typically affect large portions of the system, and should be taken into account early in the design process. Patterns have become a mainstream technique to associate frequent quality-related design problems with ...\",\n \"Title: CDFA: A Testing System for C++\\nYear: 1998\\n\\nAbstract: CDFA is a dynamic data flow analysis system for testing C++ programs. It instruments C++ programs with code that reports actions on data. The instrumented program is executed and monitored for anomalies. To effectively test C++ programs, CDFA incorporates extended actions, extended state transition diagrams, implicit state variables, functional instrumentation and object-based instrumentation.\",\n \"Title: Conformance Testing of Network Simulators Based on Metamorphic Testing Technique\\nYear: 2009\\n\\nAbstract: Network simulators, which implement network protocols under some simulated conditions, have been widely used to analyze the feasibility of network protocols. Conformance testing of the simulator against the protocol is a very important task in the community of telecommunications. However, many current conformance testing methods face a problem of finding a systematic mechanism to verify the test outputs. This paper proposes to use an innovative testing approach, metamorphic testing (MT), to alleviate such a problem. We select one ad-hoc on-demand distance vector (AODV) simulator for study and test its conformance against the AODV protocol by the MT technique. Through our experiments, we illustrate the applicability of MT in the protocol conformance testing, confirm the reliability of the selected AODV simulator, and demonstrate the cost-effectiveness of MT using the mutation analysis technique.\",\n \"Title: Testing embedded software by metamorphic testing: A wireless metering system case study\\nYear: 2011\\n\\nAbstract: In this paper, we present our experience of testing wireless embedded software. We used a wireless metering system in operation, and its software as a case study to demonstrate how a property-based testing technique, called metamorphic testing, can be used in detecting software failures of this wireless embedded system. Our study shows that a careful design of test environments and selection of system properties will enable us to trace back the cause of failures and help in fault diagnosis and debugging.\",\n \"Title: Fault class prioritization in Boolean expressions\\nYear: 2012\\n\\nAbstract: A recent study has classified faults in Boolean expressions into ten classes and has proved that there are five key fault classes, namely CCF, CDF, ORF, ENF and ASF, such that if a test suite can kill all faulty versions of these five core fault classes, if can kill all faulty versions of all fault classes. In order to generate more effective test suites, we should prioritize these five fault classes further, such that test cases with stronger fault detection capability could be generated as early as possible. Such a process is referred to as the fault class prioritization. Based on the observation in the fault class hierarchy, we divide the five fault classes into two groups {CCF, CDF} and {ORF, ENF, ASF}. Two strategies of fault class prioritization are proposed to generate test cases efficiently. We design experiments using TCAS Boolean expressions and some randomly generated Boolean expressions. The experimental results suggest that if we generate test cases for CCF and CDF firstly, the final test suite always have a higher efficiency of killing faults.\",\n \"Title: Using the Information: Incorporating Positive Feedback Information into the Testing Process\\nYear: 2003\\n\\nAbstract: Software Testing is recognized as an essential part of the Software Development process. Random Testing (RT), the selection of input test cases at random from the input domain, is a simple and efficient method of Software Testing. RT does not however make use of previously executed test case information; in particular, information about non-failure-causing test cases is ignored. Intuitively, use of this positive feedback information can improve the failure-finding efficiency of a testing method. Adaptive Random Testing (ART) makes use of knowledge of general failure pattern types, and information of previously executed test cases, in the selection of new test cases. A failure pattern in a programýs input domain is composed of the regions of failure-causing inputs. Previous research has categorized failure patterns broadly into three types: point; strip; and block, and has identified important implications for the failure- finding efficiency of test methods, depending on the failure pattern type. In particular, it has been found that for non-point type patterns, the efficiency of RT can be improved upon by simple modification of the basic approach: by ensuring a more even and widespread distribution of test cases over the input domain, the number of test cases required to find the first failure (F-measure) can be reduced dramatically. This insight has motivated several Adaptive Random Testing methods, and produced convincing results. This paper introduces some of the research in this area and suggests areas of interest for future work.\",\n \"Title: Testing and Validating Machine Learning Classifiers by Metamorphic Testing.\\nYear: 2011\\n\\nAbstract: Machine Learning algorithms have provided core functionality to many application domains - such as bioinformatics, computational linguistics, etc. However, it is difficult to detect faults in such applications because often there is no \\\"test oracle\\\" to verify the correctness of the computed outputs. To help address the software quality, in this paper we present a technique for testing the implementations of machine learning classification algorithms which support such applications. Our approach is based on the technique \\\"metamorphic testing\\\", which has been shown to be effective to alleviate the oracle problem. Also presented include a case study on a real-world machine learning application framework, and a discussion of how programmers implementing machine learning algorithms can avoid the common pitfalls discovered in our study. We also conduct mutation analysis and cross-validation, which reveal that our method has high effectiveness in killing mutants, and that observing expected cross-validation result alone is not sufficiently effective to detect faults in a supervised classification program. The effectiveness of metamorphic testing is further confirmed by the detection of real faults in a popular open-source classification program.\",\n \"Title: The universal safeness of test allocation strategies for partition testing\\nYear: 2000\\n\\nAbstract: Given a specification, a partition testing strategy is said to be safe for a program if it is not less probable of detecting at least one failure than random testing, and universally safe, if it is safe for every program. The proportional sampling strategy (PSS) has previously been proved to be universally safe. This paper extends previous results by proving that PSS is actually the only universally safe test allocation strategy for partition testing, thereby settling an open problem in the search for universally safe strategies. Despite this, we show that a close approximation to PSS may still be safe for most programs. We also discuss the practical implications of this result. (C) 2000 Elsevier Science Inc. All rights reserved.\",\n \"Title: Formalization of equivalence of recursively defined functions\\nYear: 1978\\n\\nAbstract: In this paper we use the fixpoint approach in formalizing the equivalence of recursively defined functions within the framework of predicate calculus. The results suggest some general mathematical techniques useful in proving equivalence of recursive programs.\",\n \"Title: A revisit of adaptive random testing by restriction\\nYear: 2004\\n\\nAbstract: Adaptive random testing is a black box testing method based on the intuition that random testing failure-finding efficiency can be improved upon, in certain situations, by ensuring a more widespread and evenly distributed spread of test cases in the input domain. One way of achieving this distribution is through the use of exclusion zones and restriction, resulting in a method called restricted random testing (RRT). Recent investigations into the RRT method have revealed several interesting and significant insights. A method of reducing the computational overheads of testing methods by partitioning an input domain, and applying the method to only one of the subdomains, mapping the test cases to other subdomains, has recently been introduced. This method, called mirroring, in addition to alleviating computational costs, has some properties which fit nicely with the insights into RRT, offering solutions to some possible shortcomings of RRT. In this paper we discuss the RRT method and additional insights; we explain mirroring; and we detail applications of mirroring to RRT. The mirror RRT method proves to be a very attractive variation of RRT\",\n \"Title: Isolating Suspiciousness from Spectrum-Based Fault Localization Techniques\\nYear: 2010\\n\\nAbstract: Spectrum-based fault localization (SBFL) is one of the most promising fault localization approaches, which normally uses the failed and passed program spectrum to evaluate the risks for all program entities. However, it does not explicitly distinguish the different degree in definiteness between the information associated with the failed spectrum and the passed spectrum, which may result in an unreliable location of faults. Thus in this paper, we propose a refinement method to improve the accuracy of the predication by SBFL, through eliminating the indefinite information. Our method categorizes all statements into two groups according to their different suspiciousness, and then uses different evaluation schemes for these two groups. In this way, we can reduce the use of the unreliable information in the ranking list, and finally provide a more precise result. Experimental study shows that for some SBFL techniques, our method can significantly improve their performance in some situations, and in other cases, it can still remain the techniques’ original performance.\",\n \"Title: Teaching an End-User Testing Methodology\\nYear: 2010\\n\\nAbstract: One important focus of software engineering is how to develop quality software. Software testing is the main approach to the software quality assurance. Nowadays, more and more end-users write the program on their own but lack formal trainings on how to test their programs, and hence cannot guarantee the quality of their own software. Metamorphic testing is a simple, automatable, and cost-effective testing methodology. It is particularly suitable for end-users to test their own programs, because it does not demand the user to have great knowledge of software testing but knowledge of the program under development. In this paper, we report our experience in teaching metamorphic testing to various groups of students at Swinburne University of Technology, Melbourne, Australia. Our work not only enhances the teaching of software testing, but also fosters the training of end-user programmers.\",\n \"Title: Metamorphic Testing: Applications and Integration with Other Methods: Tutorial Synopsis\\nYear: 2012\\n\\nAbstract: In software testing, an oracle refers to a mechanism against which testers can decide whether or not outcomes of test case executions are correct. The oracle problem refers to situations when either an oracle is not available, or it is too expensive to apply. Metamorphic testing has emerged as an effective and efficient approach to alleviating the oracle problem. This article introduces the basic concepts and procedures of metamorphic testing, and gives examples to show its applications, and integration with other methods.\",\n \"Title: Testing A Software-Based Pid Controller Using Metamorphic Testing\\nYear: 2011\\n\\nAbstract: The Proportional-Integral-Derivative (PID) controller is ubiquitous in industrial and military systems. Almost all PID controllers are now implemented as software in a microcontroller. Control systems are required to have very high reliability, particularly as they are regularly used in safety-critical systems. An effective testing technique is essential to achieve reliable PID controller software. Unlike simple control algorithms, PID controllers are capable of manipulating the process inputs based on the history and rate of change of the signal. It is very difficult to know whether the computation of the software is correct from the computed outputs. Previous research in other areas has shown that metamorphic testing is an effective technique for this kind of problem. In this paper, we examine metamorphic testing in the context of testing an embedded software PID controller based on the free sample code from ATMEL Corporation. We show that metamorphic testing killed all mutants inserted into the controller software, demonstrating the utility of the technique in testing control systems.\",\n \"Title: Formalization of correctness of recursive definitions\\nYear: 1980\\n\\nAbstract: We use the fixpoint approach to formalize the correctness of recursive definitions within the framework of first-order predicate calculus. Although the least fixpoint semantics is used, our results suggest some general methods of proving the correctness of recursive definitions without knowing their least fixpoints explicitly.\",\n \"Title: Two test data selection strategies towards testing of Boolean specifications\\nYear: 1997\\n\\nAbstract: Test data selection for software represented as Boolean formulae has not received much attention until the last decade. Most of the approaches are expression driven because generation of test cases is based on the Boolean formulae being tested. The paper discusses test data generation using a fault based approach in the sense that generation of test cases is based on particular types of faults occurring in the Boolean expression. Two special types of faults are considered. Moreover, two strategies of test case selection that guarantee the detection of these two types of faults are proposed.\",\n \"Title: An orchestrated survey of methodologies for automated software test case generation\\nYear: 2013\\n\\nAbstract: Test case generation is among the most labour-intensive tasks in software testing. It also has a strong impact on the effectiveness and efficiency of software testing. For these reasons, it has been one of the most active research topics in software testing for several decades, resulting in many different approaches and tools. This paper presents an orchestrated survey of the most prominent techniques for automatic generation of software test cases, reviewed in self-standing sections. The techniques presented include: (a) structural testing using symbolic execution, (b) model-based testing, (c) combinatorial testing, (d) random testing and its variant of adaptive random testing, and (e) search-based testing. Each section is contributed by world-renowned active researchers on the technique, and briefly covers the basic ideas underlying the method, the current state of the art, a discussion of the open research problems, and a perspective of the future development of the approach. As a whole, the paper aims at giving an introductory, up-to-date and (relatively) short overview of research in automatic test case generation, while ensuring a comprehensive and authoritative treatment.\",\n \"Title: Distribution Metric Driven Adaptive Random Testing\\nYear: 2007\\n\\nAbstract: Adaptive random testing (ART) was developed to enhance the failure detection capability of random testing. The basic principle of ART is to enforce random test cases evenly spread inside the input domain. Various distribution metrics have been used to measure different aspects of the evenness of test case distribution. As expected, it has been observed that the failure detection capability of an ART algorithm is related to how evenly test cases are distributed. Motivated by such an observation, we propose a new family of ART algorithms, namely distribution metric driven ART, in which, distribution metrics are key drivers for evenly spreading test cases inside ART. Out study uncovers several interesting results and shows that the new algorithms can spread test cases more evenly, and also have better failure detection capabilities.\",\n \"Title: Towards Dynamic Random Testing for Web Services\\nYear: 2012\\n\\nAbstract: In recent years, Service Oriented Architecture (SOA) has been increasingly adopted to develop applications in the context of Internet. To develop reliable SOA-based applications, an important issue is how to ensure the quality of Web services. In this paper, we propose a dynamic random testing (DRT) technique for Web services which is an improvement of the widely practiced random testing. We examine key issues when adapting DRT to the context of SOA and develop a prototype for such an adaptation. Empirical studies are reported where DRT is used to test two real-life Web services and mutation analysis is employed to measure the effectiveness. The experimental results show that DRT can save up to 24% test cases in terms of detecting the first seeded fault, and up to 21% test cases in terms of detecting all seeded faults, both with the cases of uniformed mutation analysis and distribution-aware mutation analysis, which refer to faults being seeded in an even or clustered way, respectively. The proposed DRT and the prototype provide an effective approach to testing Web Services.\",\n \"Title: Automatic Verification Of Optimization Algorithms: A Case Study Of A Quadratic Assignment Problem Solver\\nYear: 2011\\n\\nAbstract: Metamorphic testing is a technique for the verification of software output without a complete testing oracle. Mathematical optimization, implemented in software, is a problem for which verification can often be challenging. In this paper, we apply metamorphic testing to one such optimization problem, the quadratic assignment problem (QAP). From simple observations of the properties of the QAP, we describe how to derive a number of metamorphic relations useful for verifying the correctness of a QAP solver. We then compare the effectiveness of these metamorphic relations, in \\\"killing\\\" mutant versions of an exact QAP solver, to a simulated oracle. We show that metamorphic testing can be as effective as the simulated oracle for killing mutants. We examine the relative effectiveness of different metamorphic relations, both singly and in combination, and conclude that combining metamorphic relations can be significantly more effective than using a single relation.\",\n \"Title: An Integrated Classification-Tree Methodology For Test Case Generation\\nYear: 2000\\n\\nAbstract: This paper describes an integrated methodology for the construction of test cases from functional specifications using the classification-tree method. It is an integration of our extensions to the classification-hierarchy table, the classification tree construction algorithm, and the classification tree restructuring technique. Based on the methodology, a prototype system ADDICT, which stands for AutomateD test Data generation system using the Integrated Classification-Tree method, has been built.\",\n \"Title: Automatic generation of test cases from Boolean specifications using the MUMCUT strategy\\nYear: 2006\\n\\nAbstract: A recent theoretical study has proved that the MUMCUT testing strategy (1) guarantees to detect seven types of fault in Boolean specifications in irredundant disjunctive normal form, and (2) requires only a subset of the test sets that satisfy the previously proposed MAX-A and MAX-B strategies, which can detect the same types of fault. This paper complements previous work by investigating various methods for the automatic generation of test cases to satisfy the MUMCUT strategy. We evaluate these methods by using several sets of Boolean expressions, including those derived from real airborne software systems. Our results indicate that the greedy CUN and UCN methods are clearly better than others in consistently producing significantly smaller test sets, whose sizes exhibit linear correlation with the length of the Boolean expressions in irredundant disjunctive normal form. This study provides empirical evidences that the MUMCUT strategy is indeed cost-effective for detecting the faults considered in this paper.\",\n \"Title: On The Online Parameter Estimation Problem In Adaptive Software Testing\\nYear: 2008\\n\\nAbstract: Software cybernetics is an emerging area that explores the interplay between software and control. The controlled Markov chain (CMC) approach to software testing supports the idea of software cybernetics by treating software testing as a control problem, where the software under test serves as a controlled object modeled by a controlled Markov chain and the software testing strategy serves as the corresponding controller. The software under test and the corresponding software testing strategy form a closed-loop feedback control system. The theory of controlled Markov chains is used to design and optimize the testing strategy in accordance with the testing/reliability goal given explicitly and a priori. Adaptive software testing adjusts and improves software testing strategy online by using the testing data collected in the course of software testing. In doing so, the online parameter estimations play a key role. In this paper, we study the effects of genetic algorithm and the gradient method for doing online parameter estimation in adaptive software testing. We find that genetic algorithm is effective and does not require prior knowledge of the software parameters of concern. Although genetic algorithm is computationally intensive, it leads the adaptive software testing strategy to an optimal software testing strategy that is determined by optimizing a given testing goal, such as minimizing the total cost incurred for removing a given number of defects. On the other hand, the gradient method is computationally favorable, but requires appropriate initial values of the software parameters of concern. It may lead, or fail to lead, the adaptive software testing strategy to an optimal software testing strategy, depending on whether the given initial parameter values are appropriate or not. In general, the genetic algorithm should be used instead of the gradient method in adaptive software testing. Simulation results show that adaptive software testing does work and outperforms random testing.\",\n \"Title: An Automated Tool (Idaf) To Manipulate Interaction Diagrams And Fragmentations For Multi-Agent Systems\\nYear: 1999\\n\\nAbstract: Interaction diagrams are used in multi-agent systems to graphically describe agent computation threads and communications while fragmentations are the algebraic representations of interaction diagrams. The IDAF (Interaction Diagrams And Fragmentations) tool suite has been developed based on the formalism of interaction diagrams and fragmentations. The tool suite consists of ValidatoR, FormatteR, TranslatoR, GrapheR and TesteR. This paper describes the usage of the tool suite and demonstrates it in two different multi-agent systems.\",\n \"Title: An enhanced flow analysis technique for detecting unreachability faults in concurrent systems\\nYear: 2012\\n\\nAbstract: We present a flow analysis technique for detecting unreachable states and actions in concurrent systems. It is an enhancement of the approach by Cheung and Kramer. Each process of a concurrent system is modeled as a finite state machine, whose states represent process execution states and whose transitions are labeled by actions. We construct dependency sets incrementally and eliminate spurious paths by checking the execution sequences of actions. We prove mathematically that our algorithm can detect more unreachability faults than the well-known Reif/Smolka and Cheung/Kramer algorithms. The algorithm is easy to manage and its complexity is still polynomial to the system size. Case studies on two commonly used communication protocols show that the technique is effective.\",\n \"Title: Teaching automated test case generation\\nYear: 2005\\n\\nAbstract: Software testing is a major approach to software quality assurance, but it is relatively neglected in universities' computing curricula. For students majoring in computer science or software engineering, several basic testing methods need to be taught. These testing methods generate test cases based on either specifications or program code. When introducing the testing methods based on program code, it is not easy to let the students experience automated test case generation due to the lack of supporting tools and limited teaching hours. In this paper we report our experience in teaching this topic with limited resources. The evaluation result indicates that our teaching method is effective and can also be adopted in other computer science/software engineering subjects where similar constraints exist.\",\n \"Title: Distributing test cases more evenly in adaptive random testing\\nYear: 2008\\n\\nAbstract: Adaptive random testing (ART) has recently been proposed to enhance the failure-detection capability of random testing. In ART, test cases are not only randomly generated, but also evenly spread over the input domain. Various ART algorithms have been developed to evenly spread test cases in different ways. Previous studies have shown that some ART algorithms prefer to select test cases from the edge part of the input domain rather than from the centre part, that is, inputs do not have equal chance to be selected as test cases. Since we do not know where the failure-causing inputs are prior to testing, it is not desirable for inputs to have different chances of being selected as test cases. Therefore, in this paper, we investigate how to enhance some ART algorithms by offsetting the edge preference, and propose a new family of ART algorithms. A series of simulations have been conducted and it is shown that these new algorithms not only select test cases more evenly, but also have better failure detection capabilities.\",\n \"Title: On Some Properties of the Optimally Refined Proportional Sampling Strategy\\nYear: 1997\\n\\nAbstract: The optimally refined proportional sampling strategy has been recommended as a better alternative to random testing, when dividing the input domain into equal-sized partitions is easy. This paper investigates some properties of the optimally refined proportional sampling strategy. This investigation provides some useful information on how well the optimally refined proportional sampling strategy o...\",\n \"Title: Scenario-Oriented Testing for Web Service Compositions Using BPEL\\nYear: 2012\\n\\nAbstract: Applications are increasingly constructed by orchestrating Web services. Ensuring the reliability of such loosely coupled service compositions is a challenging task. In this paper, we propose an automatic scenario-oriented testing approach for service compositions specified by Business Process Execution Language (BPEL). In our approach, an abstract test model (BGM) is first defined to represent the control flows of BPEL specifications, then test scenarios are derived from the BGM with respect to the given coverage criteria, finally test data are generated to drive the execution of resulting test scenarios. A case study is conducted to demonstrate how our approach can be applied to complex real-life service compositions and the experimental results validate the effectiveness of our approach.\",\n \"Title: Impacts of Test Suite's Class Imbalance on Spectrum-Based Fault Localization Techniques\\nYear: 2013\\n\\nAbstract: Spectrum-based fault localization (SBFL) uses the execution results of test cases to debug. There are two types of SBFL techniques: one using conventional slices, and the other using metamorphic slices. This paper investigates the ratio between non-violated and violated metamorphic test groups of test suites for SBFL techniques using metamorphic slices. We have observed that the higher the ratio of passed metamorphic test groups to failed metamorphic test groups, the less effective the SBFL techniques using metamorphic slices. This observation is consistent with what has been observed in SBFL techniques using conventional slices. Besides, a new real-life fault in schedule2 of Siemens Suite is identified in our experiments.\",\n \"Title: Metamorphic slice: An application in spectrum-based fault localization\\nYear: 2013\\n\\nAbstract: Context: Because of its simplicity and effectiveness, Spectrum-Based Fault Localization (SBFL) has been one of the popular approaches towards fault localization. It utilizes the execution result of failure or pass, and the corresponding coverage information (such as program slice) to estimate the risk of being faulty for each program entity (such as statement). However, all existing SBFL techniques assume the existence of a test oracle to determine the execution result of a test case. But, it is common that test oracles do not exist, and hence the applicability of SBFL has been severely restricted. Objective: We aim at developing a framework that can extend the application of SBFL to the common situations where test oracles do not exist. Method: Our approach uses a new concept of metamorphic slice resulting from the integration of metamorphic testing and program slicing. In SBFL, instead of using the program slice and the result of failure or pass for an individual test case, a metamorphic slice and the result of violation or non-violation of a metamorphic relation are used. Since we need not know the execution result for an individual test case, the existence of a test oracle is no longer a requirement to apply SBFL. Results: An experimental study involving nine programs and three risk evaluation formulas was conducted. The results show that our proposed solution delivers a performance comparable to the performance observed by existing SBFL techniques for the situations where test oracles exist. Conclusion: With respect to the problem that SBFL is only applicable to programs with test oracles, we propose an innovative solution. Our solution is not only intuitively appealing and conceptually feasible, but also practically effective. Consequently, test oracles are no longer mandatory for SBFL, and hence the applicability of SBFL is significantly extended.\",\n \"Title: Enhancing adaptive random testing for programs with high dimensional input domains or failure-unrelated parameters\\nYear: 2008\\n\\nAbstract: Adaptive random testing (ART), an enhancement of random testing (RT), aims to both randomly select and evenly spread test cases. Recently, it has been observed that the effectiveness of some ART algorithms may deteriorate as the number of program input parameters (dimensionality) increases. In this article, we analyse various problems of one ART algorithm, namely fixed-sized-candidate-set ART (FSCS-ART), in the high dimensional input domain setting, and study how FSCS-ART can be further enhanced to address these problems. We propose to add a filtering process of inputs into FSCS-ART to achieve a more even-spread of test cases and better failure detection effectiveness in high dimensional space. Our study shows that this solution, termed as FSCS-ART-FE, can improve FSCS-ART not only in the case of high dimensional space, but also in the case of having failure-unrelated parameters. Both cases are common in real life programs. Therefore, we recommend using FSCS-ART-FE instead of FSCS-ART whenever possible. Other ART algorithms may face similar problems as FSCS-ART; hence our study also brings insight into the improvement of other ART algorithms in high dimensional space.\",\n \"Title: Adaptive Random Testing: The ART of test case diversity\\nYear: 2010\\n\\nAbstract: Random testing is not only a useful testing technique in itself, but also plays a core role in many other testing methods. Hence, any significant improvement to random testing has an impact throughout the software testing community. Recently, Adaptive Random Testing (ART) was proposed as an effective alternative to random testing. This paper presents a synthesis of the most important research results related to ART. In the course of our research and through further reflection, we have realised how the techniques and concepts of ART can be applied in a much broader context, which we present here. We believe such ideas can be applied in a variety of areas of software testing, and even beyond software testing. Amongst these ideas, we particularly note the fundamental role of diversity in test case selection strategies. We hope this paper serves to provoke further discussions and investigations of these ideas.\",\n \"Title: An effective testing method for end-user programmers\\nYear: 2005\\n\\nAbstract: End-user programmers do not have extensive knowledge of various software testing methodologies used by professional testers. While they are creating the vast majority of software today, errors are pervasive in the programs due to the lack of testing techniques readily adoptable by end-user programmers. In this article we argue that the technique of metamorphic testing is both practical and effective for end-user programmers.\",\n \"Title: Dividing strategies for the optimization of a test suite\\nYear: 1996\\n\\nAbstract: Use of the divide-and-conquer approach to optimize a test suite does not guarantee that the optimal solutions could be re-constructed from those of the sub-problems. This paper investigates how the re-construction could be achieved with two dividing strategies. Results of a simulation study are also reported.\",\n \"Title: Error Detection in C++ through Dynamic Data Flow Analysis\\nYear: 1997\\n\\nAbstract: Recently Chen and Low [5] have investigated the feasibility of using dynamic data flow analysis to test C++ programs. They concluded that the conventional state transition diagram and state variables were too primitive to detect errors in C++ programs. They proposed that class information should be included in the definitions of the state transition diagram and state variables. This paper further investigates the types of errors and how such errors could be detected using the technique of dynamic data flow analysis with the incorporation of their proposal.\",\n \"Title: Formalization of properties of nondeterministic recursive definitions\\nYear: 1980\\n\\nAbstract: This paper is concerned with the relationship between the correctness and equivalence of nondeterministic recursive definitions and the satisfiability or validity of certain first-order formulas. Our results suggest some general mathematical techniques useful in verifying the properties of nondeterministic recursive programs.\",\n \"Title: Choices, choices: comparing between CHOC'LATE and the classification-tree methodology\\nYear: 2012\\n\\nAbstract: Two popular specification-based test case generation methods are the choice relation framework and the classification-tree methodology. Both of them come with associated tools and have been used in different applications with success. Since both methods are based on the idea of partition testing, they are similar in many aspects. Because of their similarities, software testers often find it difficult to decide which method to be used in a given testing scenario. This paper aims to provide a solution by first contrasting the strengths and weaknesses of both methods, followed by suggesting practical selection guidelines to cater for different testing scenarios.\",\n \"Title: A Study On A Path-Based Strategy For Selecting Black-Box Generated Test Cases\\nYear: 2001\\n\\nAbstract: Various black-box methods for the generation of test cases have been proposed in the literature. Many of these methods, including the category-partition method and the classification-tree method, follow the approach of partition testing, in which the input domain is partitioned into subdomains according to important aspects of the specification, and test cases are then derived from the subdomains. Though comprehensive in terms of these important aspects, execution of all the test cases so generated may not be feasible under the constraint of tight testing resources. In such circumstances, there is a need to select a smaller subset of test cases from the original test suite for execution. In this paper, we propose the use of white-box information to guide the selection of test cases from the original test suite generated by a black-box testing method. Furthermore, we have developed some techniques and algorithms to facilitate the implementation of our approach, and demonstrated its viability and benefits by means of a case study.\",\n \"Title: Adaptive random testing through iterative partitioning\\nYear: 2006\\n\\nAbstract: Random testing (RT) is a fundamental and important software testing technique. Based on the observation that failure-causing inputs tend to be clustered together in the input domain, the approach of Adaptive Random Testing (ART) has been proposed to improve the fault-detection capability of RT. ART employs the location information of previously executed test cases to enforce an even spread of random test cases over the entire input domain. There have been several implementations (algorithms) of ART based on different intuitions and principles. Due to the nature of the principles adopted, these implementations have their own advantages and disadvantages. The majority of them require intensive computations to ensure the generation of evenly spread test cases, and hence incur high overhead. In this paper, we propose the notion of iterative partitioning to reduce the amount of the computation while retaining a high fault-detection capability. As a result, the cost effectiveness of ART has been improved.\",\n \"Title: Adaptive random testing through test profiles\\nYear: 2011\\n\\nAbstract: Random testing (RT), which simply selects test cases at random from the whole input domain, has been widely applied to test software and assess the software reliability. However, it is controversial whether RT is an effective method to detect software failures. Adaptive random testing (ART) is an enhancement of RT in terms of failure-detection effectiveness. Its basic intuition is to evenly spread random test cases all over the input domain. There are various notions to achieve the goal of even spread, and each notion can be implemented by different algorithms. For example, ‘by exclusion’ and ‘by partitioning’ are two different notions to evenly spread test cases. Restricted random testing (RRT) is a typical algorithm for the notion of ‘by exclusion’, whereas the notion of ‘by partitioning’ can be implemented by either the technique of bisection (ART-B) or the technique of random partitioning (ART-RP). In this paper, we propose a generic approach that can be used to implement different notions. In the new approach, test cases are simply selected based on test profiles that are in turn designed according to certain notions. In this study, we design several test profiles for the notions of ‘by exclusion’ and ‘by partitioning’, and then use these profiles to illustrate our new approach. Our experimental results show that compared with the original RRT, ART-B, and ART-RP algorithms, our new approach normally brings at least a higher failure-detection capability or a lower computational overhead. Copyright © 2011 John Wiley & Sons, Ltd. (A preliminary version of this paper was presented at the 10th International Conference on Quality Software (QSIC 2010)).\",\n \"Title: Application of Metamorphic Testing to Supervised Classifiers.\\nYear: 2009\\n\\nAbstract: Many applications in the field of scientific computing - such as computational biology, computational linguistics, and others - depend on Machine Learning algorithms to provide important core functionality to support solutions in the particular problem domains. However, it is difficult to test such applications because often there is no \\\"test oracle\\\" to indicate what the correct output should be for arbitrary input. To help address the quality of such software, in this paper we present a technique for testing the implementations of supervised machine learning classification algorithms on which such scientific computing software depends. Our technique is based on an approach called \\\"metamorphic testing\\\", which has been shown to be effective in such cases. More importantly, we demonstrate that our technique not only serves the purpose of verification, but also can be applied in validation. In addition to presenting our technique, we describe a case study we performed on a real-world machine learning application framework, and discuss how programmers implementing machine learning algorithms can avoid the common pitfalls discovered in our study. We also discuss how our findings can be of use to other areas outside scientific computing, as well.\",\n \"Title: On the Completeness of a Test Suite Reduction Strategy\\nYear: 1999\\n\\nAbstract: The problem of test suite reduction is to find a subset of test cases from the test suite that can still satisfy the same testing objective. Such a subset is referred to as a representative set of the test suite. We use a problem reduction technique, namely the 1-to-1 redundancy dividing strategy, to find the optimal representative sets, which are the representative sets of the smallest size. The ...\",\n \"Title: A more general sufficient condition for partition testing to be better than random testing\\nYear: 1996\\n\\nAbstract: Partition testing is an approach to program testing in which the input domain of the program is divided into partitions and test cases are selected from each partition. An alternative approach, known as random testing, is to select test cases at random from the entire input domain. Weyuker and Jeng (1991) observed that if all partitions are equal in sizes and the number of test cases selected from each partition is the same, then partition testing has a better chance of detecting at least one failure than random testing. This condition has been generalized by Chen and Yu (1994). They proved that partition testing is better than random testing so long as test cases are selected in proportion to the size of partitions. In this paper, we prove a more general sufficient condition. Partition testing performs better if the sampling rates are higher for partitions with higher failure rates. Some special cases that follow from this result are also considered.\",\n \"Title: Prioritization Of Combinatorial Test Cases By Incremental Interaction Coverage\\nYear: 2013\\n\\nAbstract: Combinatorial interaction testing is a well-recognized testing method, and has been widely applied in practice, often with the assumption that all test cases in a combinatorial test suite have the same fault detection capability. However, when testing resources are limited, an alternative assumption may be that some test cases are more likely to reveal failure, thus making the order of executing the test cases critical. To improve testing cost-effectiveness, prioritization of combinatorial test cases is employed. The most popular approach is based on interaction coverage, which prioritizes combinatorial test cases by repeatedly choosing an unexecuted test case that covers the largest number of uncovered parameter value combinations of a given strength (level of interaction among parameters). However, this approach suffers from some drawbacks. Based on previous observations that the majority of faults in practical systems can usually be triggered with parameter interactions of small strengths, we propose a new strategy of prioritizing combinatorial test cases by incrementally adjusting the strength values. Experimental results show that our method performs better than the random prioritization technique and the technique of prioritizing combinatorial test suites according to test case generation order, and has better performance than the interaction-coverage-based test prioritization technique in most cases.\",\n \"Title: An innovative approach for testing bioinformatics programs using metamorphic testing.\\nYear: 2009\\n\\nAbstract: Background: Recent advances in experimental and computational technologies have fueled the development of many sophisticated bioinformatics programs. The correctness of such programs is crucial as incorrectly computed results may lead to wrong biological conclusion or misguide downstream experimentation. Common software testing procedures involve executing the target program with a set of test inputs and then verifying the correctness of the test outputs. However, due to the complexity of many bioinformatics programs, it is often difficult to verify the correctness of the test outputs. Therefore our ability to perform systematic software testing is greatly hindered. Results: We propose to use a novel software testing technique, metamorphic testing (MT), to test a range of bioinformatics programs. Instead of requiring a mechanism to verify whether an individual test output is correct, the MT technique verifies whether a pair of test outputs conform to a set of domain specific properties, called metamorphic relations (MRs), thus greatly increases the number and variety of test cases that can be applied. To demonstrate how MT is used in practice, we applied MT to test two open-source bioinformatics programs, namely GNLab and SeqMap. In particular we show that MT is simple to implement, and is effective in detecting faults in a real-life program and some artificially fault-seeded programs. Further, we discuss how MT can be applied to test programs from various domains of bioinformatics.\",\n \"Title: A revisit of three studies related to random testing.\\nYear: 2015\\n\\nAbstract: Software testing is an approach that ensures the quality of software through execution, with a goal being to reveal failures and other problems as quickly as possible. Test case selection is a fundamental issue in software testing, and has generated a large body of research, especially with regards to the effectiveness of random testing (RT), where test cases are randomly selected from the software’s input domain. In this paper, we revisit three of our previous studies. The first study investigated a sufficient condition for partition testing (PT) to outperform RT, and was motivated by various controversial and conflicting results suggesting that sometimes PT performed better than RT, and sometimes the opposite. The second study aimed at enhancing RT itself, and was motivated by the fact that RT continues to be a fundamental and popular testing technique. This second study enhanced RT fault detection effectiveness by making use of the common observation that failure-causing inputs tend to cluster together, and resulted in a new family of RT techniques: adaptive random testing (ART), which is random testing with an even spread of test cases across the input domain. Following the successful use of failure-causing region contiguity insights to develop ART, we conducted a third study on how to make use of other characteristics of failure-causing inputs to develop more effective test case selection strategies. This third study revealed how best to approach testing strategies when certain characteristics of the failure-causing inputs are known, and produced some interesting and important results. In revisiting these three previous studies, we explore their unexpected commonalities, and identify diversity as a key concept underlying their effectiveness. This observation further prompted us to examine whether or not such a concept plays a role in other areas of software testing, and our conclusion is that, yes, diversity appears to be one of the most important concepts in the field of software testing.\",\n \"Title: Adaptive and Random Partition Software Testing\\nYear: 2014\\n\\nAbstract: Random testing (RT) and subdomain testing are two major software testing strategies. Their simplicity makes them likely the most efficient testing strategies with respect to the time required for test case selection. However, the disadvantage of RT is its defect detection effectiveness. Adaptive testing (AT) is a feedback-based software testing strategy that has been shown to be more effective than RT and partition testing (PT). However, a major concern in the application of AT is its complexity and computational cost for test case selection. In this paper, we propose a hybrid approach that uses AT and random partition testing (RPT) in an alternating manner. The motivation for this approach is that both strategies are employed such that the underlying computational complexity of AT is reduced by introducing RPT into the testing process without affecting the defect detection effectiveness. A case study with seven real-life subject programs is presented. The experimental results demonstrate that this novel strategy considerably reduces the computational overhead of the original AT strategy but still outperforms the pure RT strategy and PT strategy in terms of the number of test cases used to detect and remove a given number of defects. In addition, a sensitivity analysis is conducted to validate the robustness of our strategy.\",\n \"Title: How Can Non-Technical End Users Effectively Test Their Spreadsheets?\\nYear: 2014\\n\\nAbstract: Purpose - An alarming number of spreadsheet faults have been reported in the literature, indicating that effective and easy-to-apply spreadsheet testing techniques are not available for \\\"non-technical,\\\" end-user programmers. The purpose of this paper is to alleviate the problem by introducing a metamorphic testing (MT) technique for spreadsheets.Design/methodology/approach - The paper discussed four common challenges encountered by end-user programmers when testing a spreadsheet. The MT technique was then discussed and how it could be used to solve the common challenges was explained. An experiment involving several \\\"real-world\\\" spreadsheets was performed to determine the viability and effectiveness of MT.Findings - The experiment confirmed that MT is highly effective in spreadsheet fault detection, and yet MT is a general technique that can be easily used by end-user programmers to test a large variety of spreadsheet applications.Originality/value - The paper provides a detailed discussion of some common challenges of spreadsheet testing encountered by end-user programmers. To the best of the authors knowledge, the paper is the first that includes an empirical study of how effective MT is in spreadsheet fault detection from an end-user programmer's perspective.\",\n \"Title: Bottom-up Integration Testing with the Technique of Metamorphic Testing\\nYear: 2014\\n\\nAbstract: In previous studies on the application of Metamorphic Testing (MT), testing was usually conducted at the system level directly, without any well-planned integration strategy. This could lead to a difficulty in constructing Metamorphic Relations (MRs), as well as tracking and debugging the faults. On the other hand, traditional integration testing requires extra cost. In this paper, we combine the bottom-up integration approach with MT to address all the above problems. We use the Feature Selection (FS) system to illustrate our method and a 2-phase MT is conducted. With this 2-phase MT method, we can ease the MR identification and provide a clear hierarchy to easily track and isolate the faults for a complex system. Moreover, since such an integration approach is logically achieved with MRs, it does not need to have those specific set-ups as required in traditional integration testing.\",\n \"Title: Classification-tree restructuring methodologies: a new perspective\\nYear: 2002\\n\\nAbstract: The classification-tree method developed by Grochtmann et al. (1993, 1995) provided a useful approach for constructing test cases from functional specifications. It was automated by Chen and Poon (1997, 1998) through their tree construction methodology. In a follow-up study, Chen and Poon found that the effectiveness of constructing legitimate test cases could be improved under certain circumstances via a classification-tree restructuring algorithm. We develop another tree restructuring algorithm to cater for other situations not covered previously. The algorithms complement each other. We also compare the relative effectiveness of these algorithms and provide guidelines on applying them in practice\",\n \"Title: A new approach for network vulnerability analysis\\nYear: 2015\\n\\nAbstract: We propose in this paper a novel approach to analyze network vulnerability and to obtain a quantitative value representing the level of security achieved in an arbitrary network. Unlike previous graph-based algorithms that generate attack trees (or graphs) to cover all possible sequences of vulnerabilities and therefore are not scalable, our method utilizes the attack graphpsilas principles, but directly analyzes and produces the desired security measure for a network without building the actual attack graph. The proposed approach relies on a unique evaluation of vulnerability metric defined in this paper and is demonstrated through an example of a network that provides voice over IP services.\",\n \"Title: Metamorphic Testing for Software Quality Assessment: A Study of Search Engines\\nYear: 2016\\n\\nAbstract: Metamorphic testing is a testing technique that can be used to verify the functional correctness of software in the absence of an ideal oracle. This paper extends metamorphic testing into a user-oriented approach to software verification, validation, and quality assessment, and conducts large scale empirical studies with four major web search engines: Google, Bing, Chinese Bing, and Baidu. These search engines are very difficult to test and assess using conventional approaches owing to the lack of an objective and generally recognized oracle. The results are useful for both search engine developers and users, and demonstrate that our approach can effectively alleviate the oracle problem and challenges surrounding a lack of specifications when verifying, validating, and evaluating large and complex software systems.\",\n \"Title: Metamorphic testing: a simple method for alleviating the test oracle problem\\nYear: 2015\\n\\nAbstract: The test oracle problem is regarded as one of the most challenging problems in software testing. Metamorphic testing has been developed to alleviate this problem, which is done using the relations involving relevant inputs and their outputs. This keynote speech will provide a summary of the state-of-the-art of metamorphic testing.\",\n \"Title: MT4WS: an automated metamorphic testing system for web services\\nYear: 2016\\n\\nAbstract: AbstractThe use of web services has been growing significantly, with increasingly large numbers of applications being implemented through the web. A difficulty associated with this development is the quality assurance of these services, specifically the challenges encountered when testing the applications - amongst other things, testers may not have access to the source code, and the correctness of the output may not be easily ascertained known as the oracle problem. Metamorphic testing MT has been introduced as a technique to alleviate the oracle problem. MT makes use of properties of the software under test, known as metamorphic relations, and checks whether or not these relations are violated. Since MT does not require source code to generate the metamorphic relations, it is suitable for testing web services-based applications. We have designed an XML-based language representation to facilitate the formalisation of metamorphic relations, the generation of follow-up test cases, and the verification of the test results. Based on this, we have also developed a tool to support the automation of MT for web service applications. This tool has been used in an experiment to test web services, the evaluation of which is reported in this paper.\",\n \"Title: Using Partition Information to Prioritize Test Cases for Fault Localization\\nYear: 2015\\n\\nAbstract: Fault Localization Prioritization (FLP) aims at reordering existing test cases so that the location of detected faulty components can be identified earlier, using certain fault localization techniques. Although some researchers have proposed adaptive prioritization strategies with white-box code coverage information, such information may not always be available. In this paper, we address the FLP problem using black-box information derived from partitioning the input domain. Based on the well-known technique of Spectra-Based Fault Localization (SBFL), three test case prioritization strategies are designed following some basic SBFL heuristics. The implementation of these proposed strategies relies only on the partition information, and does not require any test case execution history. Experiments show that our strategies, when compared with pure random selection, result in a faster localization of faulty statements, reducing the number of test case executions required. Here, we analyze the characteristics and merits of the three proposed strategies.\",\n \"Title: A Revisit of a Theoretical Analysis on Spectrum-Based Fault Localization\\nYear: 2015\\n\\nAbstract: As a promising automatic fault localization technique, Spectrum-Based Fault Localization (SBFL) has been proposed and widely studied for years, in which the effectiveness of risk evaluation formula is one of the most popular research topics. We have developed a framework to support the theoretical analysis of risk evaluation formulas, via subset relations. In this paper, we would like to further justify the assumptions used in our framework, which are not only to make the theoretical analysis be feasible, but they are actually required either explicitly or implicitly by SBFL.\",\n \"Title: Metamorphic Testing for Cybersecurity.\\nYear: 2016\\n\\nAbstract: Metamorphic testing (MT) can enhance security testing by providing an alternative to using a test oracle, which is often unavailable or impractical. The authors report how MT detected previously unknown bugs in real-world critical applications such as code obfuscators, giving evidence that software testing requires diverse perspectives to achieve greater cybersecurity.\",\n \"Title: Metamorphic testing as a test case selection strategy.\\nYear: 2016\\n\\nAbstract: 软件测试通过运行测试用例, 观察被测软件的输出结果是否符合预期结果来发现潜藏的故障。 然而, 判定测试输出是否正确往往会成为软件测试面临的一个挑战(称为测试预期问题)。 蜕变测试通过建立被测软件输入变量域和输出结果域的关系(称为蜕变关系), 以蜕变关系判定测试执行的正确性。 蜕变测试不仅具有良好的故障检测能力, 也是一种测试用例选择方法。 本文侧重报告蜕变测试作为一种测试用例选择策略的几个成功案例。\",\n \"Title: Looking for an MR?: try METWiki today.\\nYear: 2016\\n\\nAbstract: Metamorphic Testing (MT) has been demonstrated to successfully alleviate oracle problems in many areas, including machine learning, compilers, bioinformatics, etc. However, given a new MT task, it is still very challenging to identify enough Metamorphic Relations (MRs) which are key components of MT. Aiming at this problem, we revisited previous MT applications and realized that they could form a very valuable database. Currently there is a lack of efficient link to get testers access these historical data. Therefore, in this paper, we propose to build METWiki, an MR repository, for collection and retrieval of these MRs. By providing exploration and search facilities, testers can find their desired MRs for reuse, reference, or inference. We also illustrate three sample usages of METWiki, which show important illuminations on how MRs can be obtained in practice.\",\n \"Title: The impact of source test case selection on the effectiveness of metamorphic testing.\\nYear: 2016\\n\\nAbstract: Metamorphic Testing (MT) aims to alleviate the oracle problem. In MT, testers define metamorphic relations (MRs) which are used to generate new test cases (referred to as follow-up test cases) from the available test cases (referred to as source test cases). Both source and follow-up test cases are executed and their outputs are verified against the relevant MRs, of which any violation implies that the software under test is faulty. So far, the research on the effectiveness of MT has been focused on the selection of better MRs (that is, MRs that are more likely to be violated). In addition to MR selection, the source and follow-up test cases may also affect the effectiveness of MT. Since follow-up test cases are defined by the source test cases and MRs, selection of source test cases will then affect the effectiveness of MT. However, in existing MT studies, random testing is commonly adopted as the test case selection strategy for source test cases. This study aims to investigate the impact of source test cases on the effectiveness of MT. Since Adaptive Random Testing (ART) has been developed as an enhancement to Random Testing (RT), this study will focus on comparing the performance of RT and ART as source test case selection strategies on the effectiveness of MT. Experiment results show that ART outperforms RT on enhancing the effectiveness of MT.\",\n \"Title: A cloud-based framework for applying metamorphic testing to a bioinformatics pipeline.\\nYear: 2016\\n\\nAbstract: Testing of bioinformatics software often suffers from the oracle problem, especially when testing software that analyses human genome sequencing data. Metamorphic testing has been proposed to alleviate the oracle problem. Nonetheless, smaller research or clinical centres may be challenged by the complexity and resources required to implement a suitable metamorphic testing framework in practice. This paper presents a case study on how a cloud-based metamorphic testing framework can be applied to a widely used genomic sequencing pipeline, and discusses the future of implementing large-scale on-demand automated metamorphic testing using cloud-based resources.\",\n \"Title: Input-Driven Active Testing of Multi-threaded Programs\\nYear: 2015\\n\\nAbstract: It is still a challenge to select \\\"good\\\" test inputs for concurrent programs within limited testing resources. We present in this paper a test case diversity metric for multi-threaded programs, which evaluates a test input with its effect in exposing concurrent thread interactions. We then propose an input-driven active testing approach with two test input selection strategies based on our test case diversity metric. We implement our testing approach based on Maple, an interleaving coverage-driven active testing tool. The effectiveness and efficiency of our testing approach are compared closely with Maple, which on its own is supplied with random test inputs. Experimental results show that our testing approach can outperform the original active testing approach in the number of test inputs executed and the time usage for fulfilling the interleaving coverage criterion of Maple. The selected test inputs based on our test case diversity metric are very cost-effective in exposing concurrent thread interactions and hence can help detect concurrency bugs with less cost and effort.\",\n \"Title: A Cost-Effective Random Testing Method for Programs with Non-Numeric Inputs.\\nYear: 2016\\n\\nAbstract: Random testing (RT) has been widely used in the testing of various software and hardware systems. Adaptive random testing (ART) is a family of random testing techniques that aim to enhance the failure-detection effectiveness of RT by spreading random test cases evenly throughout the input domain. ART has been empirically shown to be effective on software with numeric inputs. However, there are two aspects of ART that need to be addressed to render its adoption more widespread—applicability to programs with non-numeric inputs, and the high computation overhead of many ART algorithms. We present a linear-order ART algorithm for software with non-numeric inputs. The key requirement for using ART with non-numeric inputs is an appropriate “distance” measure. We use the concepts of categories and choices from category-partition testing to formulate such a measure. We investigate the failure-detection effectiveness of our technique by performing an empirical study on 14 object programs, using two standard metrics—F-measure and P-measure. Our ART algorithm statistically significantly outperforms RT on 10 of the 14 programs studied, and exhibits performance similar to RT on three of the four remaining programs. The selection overhead of our ART algorithm is close to that of RT.\",\n \"Title: Test Case Prioritization Using Adaptive Random Sequence with Category-Partition-Based Distance\\nYear: 2016\\n\\nAbstract: Test case prioritization schedules test cases in a certain order aiming to improve the effectiveness of regression testing. Random sequence is a basic and simple prioritization technique, while Adaptive Random Sequence (ARS) makes use of extra information to improve the diversity of random sequence. Some researchers have proposed prioritization techniques using ARS with white-box information, such as code coverage information, or with black-box information, such as string distances of the input data. In this paper, we propose new black-box test case prioritization techniques using ARS, and the diversity of test cases is assessed by category-partition-based distance. Our experimental studies show that these new techniques deliver higher fault-detection effectiveness than random prioritization, especially in the case of smaller ratio of failed test cases. In addition, in the comparison of different distance metrics, techniques with category-partition-based distance generally deliver better fault-detection effectiveness and efficiency, meanwhile in the comparison of different ordering algorithms, our ARS-based ordering algorithms usually have comparable fault-detection effectiveness but much lower computation overhead, and thus are much more cost-effective.\",\n \"Title: Error Trapping and Metamorphic Testing for Spreadsheet Failure Detection.\\nYear: 2017\\n\\nAbstract: This study deepens the research on error trapping ET and metamorphic testing MT for detecting spreadsheet failures. It is observed that some spreadsheet developers and testers are confused between ET and MT, because the two techniques are similar to each other in some aspects. Inspired by the observation, this paper first outlines the main concepts of ET and MT using several examples for illustration. This is followed by discussing an experiment with a view to investigating and comparing the failure detection capabilities of the two techniques. The results of the experiment indicate that neither technique is sufficient in spreadsheet testing. Rather, ET and MT are complementary and they should be used together in spreadsheet testing whenever possible.\",\n \"Title: A metamorphic testing approach for supporting program repair without the need for a test oracle.\\nYear: 2017\\n\\nAbstract: •A framework to support the integration of metamorphic testing with automated program repair.•An automated program repair tool MT-GenProg.•An empirical study of the effectiveness of the integrated technique.\",\n \"Title: An Adaptive Sequence Approach for OOS Test Case Prioritization\\nYear: 2016\\n\\nAbstract: Test case prioritization (TCP) attempts to improve fault detection effectiveness by scheduling important test cases earlier, where important is determined by some criteria and strategy. Adaptive random sequences (ARSs) may be applied to improve the effectiveness of TCP in black-box testing. In this paper, to improve the effectiveness of TCP for object-oriented software, we present an ARS approach based on clustering techniques. In the proposed approach, test cases are clustered according to the number of objects and methods, using two clustering algorithms - K-means and K-medoids. Our proposed sampling strategy can construct ARSs within the clustering framework, constructing two ARS sequences based on the two clustering algorithms, which results in generated test cases with different execution sequences. We also report on experimental studies to verify the proposed approach, with the results showing that our approach can enhance the probability of earlier fault detection, and deliver higher effectiveness than random prioritization.\",\n \"Title: Human Competitiveness of Genetic Programming in Spectrum-Based Fault Localisation: Theoretical and Empirical Analysis.\\nYear: 2017\\n\\nAbstract: We report on the application of Genetic Programming to Software Fault Localisation, a problem in the area of Search-Based Software Engineering (SBSE). We give both empirical and theoretical evidence for the human competitiveness of the evolved fault localisation formulæ under the single fault scenario, compared to those generated by human ingenuity and reported in many papers, published over more than a decade. Though there have been previous human competitive results claimed for SBSE problems, this is the first time that evolved solutions have been formally proved to be human competitive. We further prove that no future human investigation could outperform the evolved solutions. We complement these proofs with an empirical analysis of both human and evolved solutions, which indicates that the evolved solutions are not only theoretically human competitive, but also convey similar practical benefits to human-evolved counterparts.\",\n \"Title: A Similarity Metric for the Inputs of OO Programs and Its Application in Adaptive Random Testing.\\nYear: 2017\\n\\nAbstract: Random testing (RT) has been identified as one of the most popular testing techniques, due to its simplicity and ease of automation. Adaptive random testing (ART) has been proposed as an enhancement to RT, improving its fault-detection effectiveness by evenly spreading random test inputs across the input domain. To achieve the even spreading, ART makes use of distance measurements between consecut...\",\n \"Title: Harnessing Multiple Source Test Cases in Metamorphic Testing: A Case Study in Bioinformatics.\\nYear: 2017\\n\\nAbstract: Metamorphic testing (MT) has been applied to software verification, validation and quality assessment. In most previous studies, research has focused on deriving metamorphic relations (MRs) such that the input of one or more follow-up test cases is generated from one source test case. We note that some programs under test (PUT) naturally take multiple inputs and process them simultaneously to generate multiple outputs. This type of programs are common in the field of big data analysis and bioinformatics. This means, in the source execution of the program, we can obtain multiple outputs from multiple source test cases. Here we consider a type of MR in which multiple follow-up test cases are generated from multiple source test cases simultaneously. We hypothesise that harnessing the outputs from multiple source test cases enables us to obtain additional information about the PUT, and therefore allows us to construct more effective MRs. In this paper, we designed a new MR to test a popular RNA sequence alignment program. Since the MR was designed based on a desirable property of the PUT (which uses a complex heuristic algorithm) rather than a necessary property, violation of this MR indicates the program outputs deviate from user expectation, hence this MR can be used for assessing the quality of the outputs. Furthermore, we note that outputs of the follow-up test cases allow us to putatively assign alignment information to some sequences that were not aligned in the source test cases, hence potentially identifying and correcting these 'false negative' outputs. We believe this case study provides important insight into designing MRs based on multiple source test cases, and how testing results can be used to improve the performance of some heuristic-based programs.\",\n \"Title: Metamorphic Testing for Adobe Data Analytics Software.\\nYear: 2017\\n\\nAbstract: It is challenging to test data analytics software because a test oracle might not be available. This study reports our experience of applying metamorphic testing to Adobe's data analytics software that is used for anomaly detection in a set of time series data. We make use of geometric transformations to build metamorphic relations and generate simple time series data as the source test cases. The results of this study show that metamorphic testing is highly effective for both verification and validation purposes. An investigation of the issues detected during metamorphic testing revealed three bugs in the software under test.\",\n \"Title: A Revisit of the Integration of Metamorphic Testing and Test Suite Based Automated Program Repair.\\nYear: 2017\\n\\nAbstract: The technique of metamorphic testing (MT) has been integrated with test suite based automated program repair (APR) to alleviate the test oracle problem of APR. The proposed integration yields APR-MT techniques, which can be applied regardless of the existence of a test oracle. In a previous study, the feasibility and effectiveness of the APR-MT technique have been demonstrated via GenProg-MT, an integration of MT and the APR technique GenProg. This paper aims to complement our previous study to investigate the feasibility and effectiveness of APR-MT across different categories of APR techniques. We present the integration of MT with CETI, an APR technique belonging to a different category to GenProg, and conduct experimental analysis on the integrated technique CETI-MT, showing that CETI-MT is comparable to CETI in terms of the repair effectiveness. These results not only demonstrate the feasibility of integrating MT with different categories of APR techniques, but also consolidate the effectiveness of APR-MT techniques, hence increasing the practical benefits of APR-MT techniques.\",\n \"Title: Prioritizing random combinatorial test suites.\\nYear: 2017\\n\\nAbstract: The behaviour of a system under test can be influenced by several factors, such as system configurations, user inputs, and so on. It has also been observed that many failures are caused by only a small number of factors. Combinatorial testing aims at generating a small-sized test suite that can identify such failures. Random testing, on the other hand, selects test cases in a random manner, but has sometimes achieved similar failure-finding performance to combinatorial testing. Due to limited testing resources, test case prioritization is often employed, to attempt to identify failures as early as possible. Many prioritization studies, however, have only focused on test suites constructed by combinatorial testing, ignoring randomly constructed test suites. In this paper, we report on an investigation of test case prioritization for random combinatorial test suites. We conducted a series of empirical studies involving three real-world programs, each of which used twelve random combinatorial test suites, and adopted the well-known test case prioritization technique fixed-strength interaction coverage based prioritization (FICBP). Results from the studies indicate that, FICBP with high prioritization strength achieves better interaction coverage rate than with low prioritization strength. Furthermore, when the size of the random test suite is small, it would be better to assign a prioritization strength of 2; but otherwise, a strength of 3 would be more appropriate.\",\n \"Title: Integration of Metamorphic Testing with Program Repair Methods Based on Adaptive Search Strategies and Program Equivalence.\\nYear: 2017\\n\\nAbstract: Automated program repair (APR) is a promising approach to localize faults and generate patches for program under repair. One of the test suite based APR techniques, a method leveraging Adaptive search strategies and program Equivalence (AE), has been commonly used for program repair. AE assumes the availability of test oracles, which brings the oracle problem to AE repair procedure. Metamorphic Testing (MT) has been introduced to alleviate the test oracle problem, and it tests the correctness of programs through metamorphic relations (MRs) which are relations among multiple inputs and outputs. This paper presents an integration of AE with MT (referred to as AE-MT) to extend the applicability of AE to those applications with oracle problems. To evaluate the repair effectiveness of AE-MT, an empirical study is conducted against Intro Class benchmark. We conclude that AE-MT outperforms AE in terms of success rate, but is of lower repair quality than AE.\",\n \"Title: Testing Proportional-Integral-Derivative (PID) Controller with Metamorphic Testing\\nYear: 2017\\n\\nAbstract: The controller program is the core of a safety-critical control system. However, the testing of controller program has been facing challenges because of the oracle problem. Since Proportional-Integral-Derivative (PID) controller is the most commonly used controller in the industry, this paper proposes to apply Metamorphic Testing (MT) to test it. Our experimental results show that MT is effective in testing PID controller.\",\n \"Title: Identifying Failed Test Cases Through Metamorphic Testing\\nYear: 2017\\n\\nAbstract: When testing a program without a test oracle, it is impossible to know whether a test case will lead to a failure or not. The infeasibility to identify a failed test case severely restricts the applicability of many testing, debugging and fault localization techniques. However, with the help of Metamorphic Testing (MT) which was proposed to alleviate the test oracle problem, we are able to estimate how likely a test case is a failed test case.\",\n \"Title: Test case prioritization for object-oriented software: An adaptive random sequence approach based on clustering.\\nYear: 2018\\n\\nAbstract: •A new dissimilarity metric (OMV, object method vector) for OOS test cases.•Two clustering methods to generate adaptive random sequences for OOS test cases.•A sampling strategy to construct the adaptive random sequences.•Conducting empirical studies to verify the proposed approaches.\",\n \"Title: Out of sight, out of mind: a distance-aware forgetting strategy for adaptive random testing.\\nYear: 2017\\n\\nAbstract: Adaptive random testing (ART) achieves better failure-detection effectiveness than random testing by increasing the diversity of test cases. However, the intention of ensuring even spread of test cases inevitably causes an overhead problem. Although two basic forgetting strategies (i.e. random forgetting and consecutive retention) were proposed to reduce the computation cost of ART, they only considered the temporal distribution of test cases. In the paper, we presented a distance-aware forgetting strategy for the fixed size candidate set version of ART (DF-FSCS), in which the spatial distribution of test cases is taken into consideration. For a given candidate, the test cases out of its “sight” are ignored to reduce the distance computation cost. At the same time, the dynamic adjustment for partitioning and the second-round forgetting are adopted to ensure the linear complexity of DF-FSCS algorithm. Both simulation analysis and empirical study are employed to investigate the efficiency and effectiveness of DF-FSCS. The experimental results show that DF-FSCS significantly outperforms the classical ART algorithm FSCS-ART in efficiency, and has comparable failure-detection effectiveness. Com-pared with two basic forgetting methods, DF-FSCS is better in both efficiency and effectiveness. In contrast with a typical linear-time ART algorithm RBCVT-Fast, our algorithm requires less computational overhead and exhibits the similar failure-detection capability. In addition, DF-FSCS has more reliable performance than RBCVT-Fast in detecting failures for the programs with high-dimensional input domain.\",\n \"Title: An experimental analysis of fault detection capabilities of covering array constructors.\\nYear: 2018\\n\\nAbstract: Combinatorial Interaction Testing (CIT) aims at constructing an effective test suite, such as a Covering Array (CA), that can detect faults that are caused by the interaction of parameters. In this paper, we report on some empirical studies conducted to examine the fault detection capabilities of five popular CA constructors: ACTS, Jenny, PICT, CASA, and TCA. The experimental results indicate that Jenny has the best performance, because it achieves better fault detection than the other four constructors in many cases. Our results also indicate that CAs generated using ACTS, PICT, or CASA should be prioritized before testing.\",\n \"Title: On the Selection of Strength for Fixed-Strength Interaction Coverage Based Prioritization\\nYear: 2018\\n\\nAbstract: Abstract test cases are derived by modeling the system under test, and have been widely applied in practice, such as for software product line testing and combinatorial testing. Abstract test case prioritization (ATCP) is used to prioritize abstract test cases and aims at achieving higher rates of fault detection. Many ATCP algorithms have been proposed, using different prioritization criteria and information. One ATCP approach makes use of fixed-strength level-combinations information covered by abstract test cases, and is called fixed-strength interaction coverage based prioritization (FICBP). Before using FICBP, the prioritization strength λ needs to be decided. Previous studies have generally focused on λ values ranging between 1 and 6. However, no study has investigated the appropriateness of such a range, nor how to assign the prioritization strength for FICBP. To answer these questions, this paper reports on an empirical study involving four real-life programs (each of which with six versions). The experimental results indicate that λ should be set approximately equal to a value corresponding to half of the number of parameters, when testing resources are sufficient. Our results also show that when testing resources are limited or insufficient, either small or large λ values are suggested for FICBP.\",\n \"Title: A Validation and Quality Assessment Method with Metamorphic Relations for Unsupervised Machine Learning Software.\\nYear: 2018\\n\\nAbstract: Unsupervised machine learning is a task of modeling the underlying structure of ``unlabeled datau0027u0027. Since learning algorithms have been incorporated into many real-world applications, validating the implementations of those algorithms becomes much more important in the aim of software quality assurance. However, validating unsupervised machine learning programs is challenging because there lacks of priori knowledge. Along this line, in this paper, we present a metamorphic testing based method for validating and characterizing unsupervised machine learning programs, and conduct an empirical study on a real-world machine learning tool. The results demonstrate to what extent a program may fit to the profile of a specific scenario, which help end-users or software practitioners comprehend its performance in a vivid and light-weight way. And the experimental findings also reveal the gap between theory and implementation in a software artifact which could be easily ignored by people without much practical experience. In our method, metamorphic relations can serve as one type of quality measure, and one type of guidelines for selecting suitable programs.\",\n \"Title: Metamorphic Testing for Adobe Analytics Data Collection JavaScript Library.\\nYear: 2018\\n\\nAbstract: In recent years, metamorphic testing has been successfully and systematically adopted within Adobe Systems to improve the cost effectiveness of its software process. In this industry experience report, we present a case where metamorphic testing has been applied to the Data Collection JavaScript Library of Adobe Analytics. This type of software is difficult to test using traditional approaches. The application of metamorphic testing alleviated the oracle problem, and detected real-life bugs in the system under test as well as compatibility problems between the system and its environment, namely, the Internet Explorer browser. Our results further justify the adoption of metamorphic testing as a simple yet effective approach in industrial settings.\",\n \"Title: Enhancing Supervised Classifications with Metamorphic Relations.\\nYear: 2018\\n\\nAbstract: We report on a novel use of metamorphic relations (MRs) in machine learning: instead of conducting metamorphic testing, we use MRs for the augmentation of the machine learning algorithms themselves. In particular, we report on how MRs can enable enhancements to an image classification problem of images containing hidden visual markers (\\\"Artcodes\\\").\\n\\nWorking on an original classifier, and using the characteristics of two different categories of images, two MRs, based on separation and occlusion, were used to improve the performance of the classifier. Our experimental results show that the MR-augmented classifier achieves better performance than the original classifier, algorithms, and extending the use of MRs beyond the context of software testing.\",\n \"Title: Diversity driven adaptive test generation for concurrent data structures.\\nYear: 2018\\n\\nAbstract: Abstract Context Testing concurrent data structures remains a notoriously challenging task, due to the nondeterminism of multi-threaded tests and the exponential explosion on the number of thread schedules. Objective We propose an automated approach to generate a series of concurrent test cases in an adaptive manner, i.e., the next test cases are generated with the guarantee to discover the thread schedules that have not yet been activated by the previous test cases. Method Two diversity metrics are presented to induce such adaptive test cases from a static and a dynamic perspective, respectively. The static metric enforces the diversity in the program structures of the test cases; while the dynamic one enforces the diversity in their capabilities of exposing untested thread schedules. We implement three adaptive test generation approaches for C/C++ concurrent data structures, based on the state-of-the-art active testing engine Maple. Results We then report an empirical study with 9 real-world C/C++ concurrent data structures, which demonstrates the efficiency of our test generation approaches in terms of the number of thread schedules discovered, as well as the time and the number of tests required for testing a concurrent data structure. Conclusion Hence, by using diverse test cases derived from the static and dynamic perspectives, our adaptive test generation approaches can deliver a more efficient coverage of the thread schedules of the concurrent data structure under test.\",\n \"Title: Adaptive Random Testing In Detecting Layout Faults Of Web Applications\\nYear: 2018\\n\\nAbstract: As part of a software testing process, output verification poses a challenge when the output is not numeric or textual, such as graphical. The industry practice of using human oracles (testers) to observe and verify the correctness of the actual results is both expensive and error-prone. In particular, this practice is usually unsustainable when developing web applications - the most popular software of our era. This is because web applications change frequently due to the fast-evolving requirements amid popular demand. To improve the cost effectiveness of browser output verification, in this study we design failure-based testing techniques and evaluate the effectiveness and efficiency thereof in the context of web testing. With a novel application of the concept of adaptive random sequence (ARS), our approach leverages peculiar characteristics of failure patterns found in browser layout rendering. An empirical study shows that the use of failure patterns and inclination to guide the testing flow leads to more cost-effective results than other classic methods. This study extends the application of ARSs from the input space of programs to their output space, and also shows that adaptive random testing (ART) can outperform random testing (RT) in both failure detection effectiveness (in terms of F-measure) and failure detection efficiency (in terms of execution time).\",\n \"Title: An Empirical Comparison of Fixed-Strength and Mixed-Strength for Interaction Coverage Based Prioritization.\\nYear: 2018\\n\\nAbstract: Test case prioritization (TCP) plays an important role in identifying, characterizing, diagnosing, and correcting faults quickly. The TCP has been widely used to order test cases of different types, including model inputs (also called abstract test cases). Model inputs are constructed by modeling the program according to its input parameters, values, and constraints, and has been used in different testing methods, such as combinatorial interaction testing and software product line testing. The Interaction coverage-based TCP (ICTCP) uses interaction coverage information derived from the model input to order inputs. Previous studies have focused generally on the fixed-strength ICTCP, which adopts a fixed strength (i.e., the level of parameter interactions) to support the ICTCP process. It is generally accepted that using more strengths for ICTCP, i.e., mixed-strength ICTCP, may give better ordering than fixed-strength. To confirm whether mixed-strength is better than fixed-strength, in this paper, we report on an extensive empirical study using five real-world programs (written in C), each of which has six versions. The results of the empirical studies show that mixed-strength has better rates of interaction coverage overall than fixed-strength, but they have very similar rates of fault detection. Our results also show that fixed-strength should be used instead of the mixed-strength at the later stage of software testing. Finally, we offer some practical guidelines for testers when using interaction coverage information to prioritize model inputs, under different testing scenarios and resources.\",\n \"Title: On the analysis of spectrum based fault localization using hitting sets.\\nYear: 2019\\n\\nAbstract: •Two variants of Sendys to patch its NOR problem and improve its performance.•First comprehensive theoretical analysis on Sendys and its variants.•A short-cut reformulation of the enhanced Sendys with the best performance.•Empirical studies on single and multiple faults to complement theoretical analysis.\",\n \"Title: Adaptive Partition Testing.\\nYear: 2019\\n\\nAbstract: Random testing and partition testing are two major families of software testing techniques. They have been compared both theoretically and empirically in numerous studies for decades, and it has been widely acknowledged that they have their own advantages and disadvantages and that their innate characteristics are fairly complementary to each other. Some work has been conducted to develop advanced...\",\n \"Title: Metamorphic testing: A new student engagement approach for a new software testing paradigm\\nYear: 2016\\n\\nAbstract: Software testing, as part of the software quality assurance processes in software engineering (SE), is seldom cited as the most engaging part of a software engineer's training. In spite of its importance, it was often a neglected area, and only recently, with the adoption of more agile methodologies, has testing come to the fore. Testers face challenges, including the need to be able to identify when software is not behaving as expected. Metamorphic Testing (MT) first appeared twenty years ago in an effort to help testers facing the oracle problem (not having a mechanism to determine correct software behavior). Although MT is simple in concept, it has demonstrated very impressive fault-finding ability, and has recently been attracting a great deal of interest. Training students and practitioners to effectively apply MT has become an important goal, but to date, no textbook or guidelines have been made readily available. This paper, written by some of the leading voices in the MT community, is a sharing of some of the experiences, reflections and insights gained through teaching MT (and other related subjects). These experiences indicate that not only is MT effective in industry and at fault-finding, it has the potential to really engage students in creative SE classroom activities.\",\n \"Title: Metamorphic Testing: A Review of Challenges and Opportunities.\\nYear: 2018\\n\\nAbstract: Metamorphic testing is an approach to both test case generation and test result verification. A central element is a set of metamorphic relations, which are necessary properties of the target function or algorithm in relation to multiple inputs and their expected outputs. Since its first publication, we have witnessed a rapidly increasing body of work examining metamorphic testing from various perspectives, including metamorphic relation identification, test case generation, integration with other software engineering techniques, and the validation and evaluation of software systems. In this article, we review the current research of metamorphic testing and discuss the challenges yet to be addressed. We also present visions for further improvement of metamorphic testing and highlight opportunities for new research.\",\n \"Title: Prioritizing Abstract Test Cases: An Empirical Study\\nYear: 2019\\n\\nAbstract: Test-case prioritisation (TCP) attempts to schedule the order of test-case execution such that faults can be detected as quickly as possible. TCP has been widely applied in many testing scenarios such as regression testing and fault localisation. Abstract test cases (ATCs) are derived from models of the system under test and have been applied to many testing environments such as model-based testing and combinatorial interaction testing. Although various empirical and analytical comparisons for some ATC prioritisation (ATCP) techniques have been conducted, to the best of the authors’ knowledge, no comparative study focusing on the most current techniques has yet been reported. In this study, they investigated 18 ATCP techniques, categorised into four classes. They conducted a comprehensive empirical study to compare 16 of the 18 ATCP techniques in terms of their testing effectiveness and efficiency. They found that different ATCP techniques could be cost-effective in different testing scenarios, allowing us to present recommendations and guidelines for which techniques to use under what conditions.\",\n \"Title: Metamorphic Testing: A Simple Yet Effective Approach for Testing Scientific Software\\nYear: 2019\\n\\nAbstract: Testing scientific software is a difficult task due to their inherent complexity and the lack of test oracles. In addition, these software systems are usually developed by \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">end-user developers</italic>\\n who are not normally trained as professional software developers nor testers. These factors often lead to inadequate testing. \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Metamorphic testing (MT)</italic>\\n is a simple yet effective testing technique for testing such applications. Even though MT is a wellknown technique in the software testing community, it is not very well utilized by the scientific software developers. The objective of this paper is to present MT as an effective technique for testing scientific software. To this end, we discuss why MT is an appropriate testing technique for scientists and engineers who are not primarily trained as software developers. Specifically, how it can be used to conduct systematic and effective testing on programs that do not have test oracles without requiring additional testing tools.\",\n \"Title: Metamorphic Testing: Testing the Untestable\\nYear: 2020\\n\\nAbstract: What if we could know that a program is buggy, even if we could not tell whether or not its observed output is correct? Metamorphic testing provides this ability. This article explains the basics of the technique.\",\n \"Title: KDFC-ART: a KD-tree approach to enhancing Fixed-size-Candidate-set Adaptive Random Testing\\nYear: 2019\\n\\nAbstract: Adaptive random testing (ART) was developed as an enhanced version of random testing to increase the effectiveness of detecting failures in programs by spreading the test cases evenly over the input space. However, heavy computation may be incurred. In this paper, three enhanced algorithms for fixed-size-candidate-set ART (FSCS-ART) are proposed based on the \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"><tex-math notation=\\\"LaTeX\\\">$k$</tex-math></inline-formula>\\n-dimensional tree (KD-tree) structure. The first algorithm Naive-KDFC constructs a KD-tree by splitting the input space with respect to every dimension successively in a round-robin fashion. The second algorithm SemiBal-KDFC improves the balance of the KD-tree by prioritizing the splitting according to the spread in each dimension. In order to control the number of traversed nodes in backtracking, the third algorithm LimBal-KDFC introduces an upper bound for the nodes involved. Simulation and empirical studies have been conducted to investigate the efficiency and effectiveness of the three algorithms. The experimental results show that these algorithms significantly reduce the computation time of the original FSCS-ART for low dimensions and for the case of high dimensions with low failure rates. The efficiency of SemiBal-KDFC is better than that of Naive-KDFC when the dimension is no more than 8, but LimBal-KDFC is the most efficient of all three. Although the limited backtracking leads only to an approximate nearest neighbor in LimBal-KDFC, its failure-detection effectiveness is, in fact, better than FSCS-ART in high-dimensional input spaces and has no significant deterioration in low-dimensional spaces.\",\n \"Title: Metamorphic relations for detection of performance anomalies\\nYear: 2019\\n\\nAbstract: Metamorphic relations can be used to improve performance testing by comparing successive runs of the software under test. We examine one such metamorphic relation for page load times, which we used to discover and repair a race condition in the Adobe Experience Platform Launch Tag Manager. Histograms for page load times had different modalities, which alerted us to the presence of the bug. We discuss the need for performance measures in addition to the popular mean and standard deviation. We describe two approaches to automatically determine modality: Gaussian Mixture Models and the Silverman Test for Multimodality. Metamorphic relations which involve these performance measures can be used to alert engineers to the presence of performance anomalies.\",\n \"Title: Using metamorphic relations to verify and enhance Artcode classification\\nYear: 2021\\n\\nAbstract: Software testing is often hindered where it is impossible or impractical to determine the correctness of the behaviour or output of the software under test (SUT), a situation known as the oracle problem. An example of an area facing the oracle problem is automatic image classification, using machine learning to classify an input image as one of a set of predefined classes. An approach to software testing that alleviates the oracle problem is metamorphic testing (MT). While traditional software testing examines the correctness of individual test cases, MT instead examines the relations amongst multiple executions of test cases and their outputs. These relations are called metamorphic relations (MRs): if an MR is found to be violated, then a fault must exist in the SUT. This paper examines the problem of classifying images containing visually hidden markers called Artcodes, and applies MT to verify and enhance the trained classifiers. This paper further examines two MRs, Separation and Occlusion, and reports on their capability in verifying the image classification using one-way analysis of variance (ANOVA) in conjunction with three other statistical analysis methods: t-test (for unequal variances), Kruskal–Wallis test, and Dunnett’s test. In addition to our previously-studied classifier, that used Random Forests, we introduce a new classifier that uses a support vector machine, and present its MR-augmented version. Experimental evaluations across a number of performance metrics show that the augmented classifiers can achieve better performance than non-augmented classifiers. This paper also analyses how the enhanced performance is obtained.\",\n \"Title: Testing multiple linear regression systems with metamorphic testing\\nYear: 2021\\n\\nAbstract: Regression is one of the most commonly used statistical techniques. However, testing regression systems is a great challenge because of the absence of test oracle in general. In this paper, we show that Metamorphic Testing is an effective approach to test multiple linear regression systems. In doing so, we identify intrinsic mathematical properties of linear regression, and then propose 11 Metamorphic Relations to be used for testing. Their effectiveness is examined using mutation analysis with a range of different regression programs. We further look at how the testing could be adopted in a more effective way. Our work is applicable to examine the reliability of predictive systems based on regression that has been widely used in economics, engineering and science, as well as of the regression calculation manipulated by statistical users.\",\n \"Title: New visions on metamorphic testing after a quarter of a century of inception\\nYear: 2021\\n\\nAbstract: ABSTRACTMetamorphic testing (MT) was introduced about a quarter of a century ago. It is increasingly being accepted by researchers and the industry as a useful testing technique. The studies, research results, applications, and extensions of MT have given us many insights and visions for its future. Our visions include: MRs will be a practical means to top up test case generation techniques, beyond the alleviation of the test oracle problem; MT will not only be a standalone technique, but conveniently integrated with other methods; MT and MRs will evolve beyond software testing, or even beyond verification; MRs may be anything that you can imagine, beyond the necessary properties of algorithms; MT research will be beyond empirical studies and move toward a theoretical foundation; MT will not only bring new concepts to software testing but also new concepts to other disciplines; MRs will alleviate the reliable test set problem beyond traditional approaches. These visions may help researchers explore the challenges and opportunities for MT in the next decade.\",\n \"Title: Perception Matters: Detecting Perception Failures of VQA Models Using Metamorphic Testing\\nYear: 2021\\n\\nAbstract: Visual question answering (VQA) takes an image and a natural-language question as input and returns a natural-language answer. To date, VQA models are primarily assessed by their accuracy on high-level reasoning questions. Nevertheless, Given that perception tasks (e.g., recognizing objects) are the building blocks in the compositional process required by high-level reasoning, there is a demanding need to gain insights into how much of a problem lowlevel perception is. Inspired by the principles of software metamorphic testing, we introduce MetaVQA, a model-agnostic framework for benchmarking perception capability of VQA models. Given an image i, MetaVQA is able to synthesize a low-level perception question q. It then jointly transforms (i, q) to one or a set of sub-questions and subimages. MetaVQA checks whether the answer to (i, q) satisfies metamorphic relationships (MRs), denoting perception consistency, with the composed answers of transformed questions and images. Violating MRs denotes a failure of answering perception questions. MetaVQA successfully detects over 4.9 million perception failures made by popular VQA models with metamorphic testing. The state-of-the-art VQA models (e.g., the champion of VQA 2020 Challenge) suffer from perception consistency problems. In contrast, the Oscar VQA models, by using anchor points to align questions and images, show generally better consistency in perception tasks. We hope MetaVQA will revitalize interest in enhancing the low-level perceptual abilities of VQA models, a cornerstone of high-level reasoning.\",\n \"Title: BMT: Behavior Driven Development-based Metamorphic Testing for Autonomous Driving Models\\nYear: 2021\\n\\nAbstract: Deep Neural Network based models are widely used for perception and control in autonomous driving. Recent work leverages metamorphic testing to improve defect detection but is limited to using only an equality-based metamorphic relation. Thus, it does not provide sufficient expressiveness for users to define custom metamorphic relations nor means to automatically generate meaningful inputs based o...\",\n \"Title: Follow-up Test Cases are Better Than Source Test Cases in Metamorphic Testing: A Preliminary Study\\nYear: 2021\\n\\nAbstract: Recently, metamorphic testing (MT) has been used to augment test datasets by inclusion of new (follow-up) test cases constructed from existing (source) test cases using metamorphic relations (MRs). It has been reported that the augmented test datasets usually have higher fault detection capabilities. It is natural to ask which contributes to the improvement of the fault detection capabilities. To ...\",\n \"Title: METRIC $^{+}$ + : A Metamorphic Relation Identification Technique Based on Input Plus Output Domains\\nYear: 2021\\n\\nAbstract: Metamorphic testing is well known for its ability to alleviate the oracle problem in software testing. The main idea of metamorphic testing is to test a software system by checking whether each identified metamorphic relation (MR) holds among several executions. In this regard, identifying MRs is an essential task in metamorphic testing. In view of the importance of this identification task, METRI...\",\n \"Title: Metamorphic Testing of Fake News Detection Software\\nYear: 2021\\n\\nAbstract: Since the popularization of social media, news has entered our lives digitally. While news is spreading broader and faster, fake news is becoming an increasingly popular topic. Fake news detection is therefore important in both social media and research areas. With artificial intelligence technology, software engineers have developed a lot of fake news detection systems. One of the biggest challenges for such systems is that they may face the oracle problem, which means that there may not be a way, or it may take too long time, to confirm the correctness of a specific output. Metamorphic Testing has been applied successfully to alleviate the oracle problem in many different areas, including in artificial intelligence. In this paper, we propose several metamorphic relations for fake news detection and report on experiments using metamorphic testing on fake news detection applications.\",\n \"Title: Metamorphic Testing for Block Ciphers\\nYear: 2021\\n\\nAbstract: Information is indispensable in modern society. People's daily communication and work depend on information transmission. Unsafe storage or transmission of data may result in privacy and security problems. One way to attempt to prevent such issues is to use encryption algorithms to transform information into encrypted forms. Because the encryption steps of most encryption algorithms are complex, deciding the correctness of the encrypted output may take a long time in practice. This kind of problem is called the Test Oracle problem. In contrast to traditional software testing, Metamorphic Testing (MT) does not focus on the correctness of each individual output, but examines whether the inputs and outputs of multiple executions of a Program Under Test (PUT) satisfy necessary relations of the PUT, called metamorphic relations. This paper reports on an experience of applying MT to test three encryption algorithms - Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), and Advanced Encryption Standard (AES).\",\n \"Title: Mtkeras: An Automated Metamorphic Testing Platform\\nYear: 2021\\n\\nAbstract: This paper presents an automated, domain-independent, metamorphic testing platform called MTKeras. In this paper, we report on an investigation demonstrating the effectiveness and usability of MTKeras through five case studies in the four domains of image classification, sentiment analysis, search engines and database management systems. We also report on the effectiveness of combining metamorphic relation (input) patterns in individual metamorphic relations, enhancing the failure-finding abilities of the individual relations. The results of our experiments support combining patterns, and the use of MTKeras. The research reported in this paper shows the applicability of metamorphic relation patterns, and introduces a practical tool for the research community.\",\n \"Title: Metamorphic testing on multi-module UAV systems\\nYear: 2021\\n\\nAbstract: BSTRACTRecent years have seen a rapid development of machine learning based multi-module unmanned aerial vehicle (UAV) systems. To address the oracle problem in autonomous systems, numerous studies have been conducted to use meta-morphic testing to automatically generate test scenes for various modules, e.g., those in self-driving cars. However, as most of the studies are based on unit testing including end-to-end model-based testing, a similar testing approach may not be equally effective for UAV systems where multiple modules are working closely together. Therefore, in this paper, instead of unit testing, we propose a novel metamorphic system testing framework for UAV, named MSTU, to detect the defects in multi-module UAV systems. A preliminary evaluation plan to apply MSTU on an emerging autonomous multi-module UAV system is also presented to demonstrate the feasibility of the proposed testing framework.\",\n \"Title: Dynamic Random Testing of Web Services: A Methodology and Evaluation\\nYear: 2022\\n\\nAbstract: In recent years, service oriented architecture (SOA) has been increasingly adopted to develop distributed applications in the context of the Internet. To develop reliable SOA-based applications, an important issue is how to ensure the quality of web services. In this article, we propose a dynamic random testing (DRT) technique for web services, which is an improvement over the widely-practiced ran...\",\n \"Title: MMFC-ART: a Fixed-size-Candidate-set Adaptive Random Testing approach based on the modified Metric-Memory tree\\nYear: 2020\\n\\nAbstract: Adaptive random testing (ART) improves the failure-detection effectiveness of Random testing (RT) by making test cases more evenly distributed in the input domain. The Fixed-size-Candidate-set ART (FSCS-ART) is one of the most classical algorithms, which selects the candidate test case furthest from the previously executed test case as the next test case. However, when the number of executed test ...\",\n \"Title: Testing Ocean Software with Metamorphic Testing\\nYear: 2022\\n\\nAbstract: Advancing ocean science has a significant impact to the development of the world, from operating a safe navigation for vessels to maintaining a healthy and diverse ocean ecosystem. Various ocean software systems have been extensively adopted for differ-ent purposes, for instance, predicting hourly sea level elevation across shorelines, simulating large-scale ocean circulations, as well as integrating into Earth system models for weather forecasts and climate projections. Regardless of their significance, guaranteeing the trustworthiness of ocean software and modelling systems is a long-standing challenge. The testing of ocean software suffers a lot from the socalled oracle problem, which refers to the absence of test oracles mainly due to the nonlinear interactions of multiple physical variables and the high complexity in computation. In the ocean, observed tidal signals are distorted by non-deterministic physical variables, hindering us from knowing the “true” astronom-ical tidal constituents existing in the timeseries. In this paper, we present how to test tidal analysis and prediction (TAP) software based on metamorphic testing (MT), a simple yet effective testing approach to the oracle problem. In particular, we construct meta-morphic relations from the periodic property of astronomical tide, and then use them to successfully detect a real-life defect in an open-source TAP software. We also conduct a series of experiments to further demonstrate the applicability and effectiveness of MT in the testing of TAP software. Our study not only justifies the poten-tial of MT in testing more complex ocean software and modelling systems, but also can be expanded to assess and improve the quality of a broader range of scientific simulation software systems.\",\n \"Title: On the effectiveness of testing sentiment analysis systems with metamorphic testing\\nYear: 2022\\n\\nAbstract: •An analysis of false satisfactions, revealing their impacts on metamorphic testing.•An application of metamorphic testing to sentiment analysis systems.•A discussion about the causes for high occurrence rates of false satisfactions.\",\n \"Title: An Extended Abstract of “Dynamic Random Testing of Web Services: A Methodology and Evaluation”\\nYear: 2022\\n\\nAbstract: [J1C2 Presentation Abstract at IEEE SERVICES 2022 for IEEE Transactions on Services Computing, 2022, 15(2):736-751. DOI: 10.1109/TSC.2019.2960496].\",\n \"Title: In-Place Metamorphic Testing and Exploration\\nYear: 2022\\n\\nAbstract: In this paper, we consider the testing of software whose input involves a data stream, such as in video analysis applications. To address the oracle problem in testing this kind of software, existing metamorphic testing (MT) and metamorphic exploration (ME) techniques typically generate both source and follow-up input streams. In contrast, we propose a different strategy: an inplace method. Instead of examining relations among multiple input streams, our method works on a finer granularity by investigating relations among the data frames within a single input stream - such as the relations among the image frames within a video stream - treating a frame, rather than a stream, as a test case. Because our method does not generate any follow-up input stream, or change any frame values, it is also suitable for runtime error detection. We have applied this in-place method to testing video streams in Baidu Apollo, a real-life autonomous driving system. Our study identified previously-unknown obstacle perception failures in the camera perception module, including both undetected and incorrectly-detected objects. The empirical results show that our approach is practical, and readily applicable to industrial-scale systems that include (but are not limited to) the computer vision domain.\",\n \"Title: Using Metamorphic Relation Violation Regions to Support a Simulation Framework for the Process of Metamorphic Testing\\nYear: 2022\\n\\nAbstract: Metamorphic testing (MT) has been growing in popularity, but it can still be quite challenging and time-consuming to assess its performance. Typical approaches to performance assessment can require a series of steps, and depend on a variety of factors, often requiring serendipity. This can be a bottleneck for some aspects of MT research. Central to MT, metamorphic relations (MRs) represent necessary properties of the system under test (SUT). In traditional software testing, simulations are often employed to examine and compare the performance of different testing strategies. However, these simulations are typically designed based on the assumed availability (and applicability) of a test oracle - a mechanism to decide the correctness of the SUT output or behaviour. A key reason for the popularity of MT is its proven record of effective software testing, without the need for a test oracle. This strength, however, also means that traditional ways of using simulations to analyse software testing approaches are not applicable for MT. This lack of cheap and fast ways to conduct simulation analyses of MT is a hurdle for many aspects of MT research, and may be an obstacle to its more widespread adoption. To address this, in this paper we introduce the concept of MR-violation regions (MRVRs), and show how they can be used for a certain category of MRs, Deterministic MRs (DMRs), to build simulation tools for MT. We analyse the differences between MRVRs and traditional, oracle-defined failure regions; and report on a preliminary case study exploring MRVRs in numerical-input-domain systems from previous MT studies. We anticipate that the proposed MT simulation framework may facilitate more research into MT, and may help lead to its more widespread adoption.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":161,"string":"161"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13353,"string":"13,353"}}},{"rowIdx":13354,"cells":{"question_id":{"kind":"string","value":"Fatih Kurugollu"},"question":{"kind":"string","value":"Generate an abstract for the title \"Spread spectrum image watermarking based on the discrete shearlet transform\" using the following items: 1. Spread Spectrum \n2. Image watermarking \n3. Discrete Shearlet Transform (DST) \n4. Resistance to attacks \n5. Experimental results"},"answer":{"kind":"string","value":"This paper presents a spread spectrum based image watermarking model that utilizes the Discrete Shearlet Transform (DST). The method employs the multiresolution representation characteristics of the DST to facilitate the modeling of the texture structure of the given image. The effectiveness of the proposed method in dealing with well-known attacks such as noise addition, blurring, compression and cropping is demonstrated by experimental results. The experimental results show that the proposed method performs well in comparison with counterpart transforms such as the Discrete Cosine Transform (DCT) and the Discrete Wavelet Transform (DWT)."},"correct_answer":{"kind":"string","value":"This paper presents a spread spectrum based image watermarking model that utilizes the Discrete Shearlet Transform (DST). The method employs the multiresolution representation characteristics of the DST to facilitate the modeling of the texture structure of the given image. The effectiveness of the proposed method in dealing with well-known attacks such as noise addition, blurring, compression and cropping is demonstrated by experimental results. The experimental results show that the proposed method performs well in comparison with counterpart transforms such as the Discrete Cosine Transform (DCT) and the Discrete Wavelet Transform (DWT)."},"documents":{"kind":"list like","value":["Title: Eigenspectra Palmprint Recognition\nYear: 2008\n\nAbstract: This paper proposes a novel technique for palmprint recognition in the transform domain and based on a combination of Principal Component Analysis (PCA) and Fourier transform. Although, PCA is widely adopted as one of the most promising tools for use in biometric recognition systems, it comes with its own limitations: poor discriminating power in the presence of variant illuminations, requires a large computational load when the original dimensionality of data is high while the number of training samples is usually large. Traditionally, to represent the palmprint image, PCA is carried out on the whole spatial image. In the proposed method, Fourier transform is used to decompose an image into its sine and cosine components, then the spectrum is used for PCA representation since doing PCA on the whole frequency domain does not achieve any performance improvements. In comparison with the traditional PCA and three other methods, the proposed method yields better recognition accuracy and discriminating. In addition, the proposed method reduces the computational load significantly to half due to the symmetry property of Fourier transform.","Title: A novel universal steganalyser design: “LogSv”\nYear: 2009\n\nAbstract: This paper introduces a novel universal steganalysis method in order to attack especially spatial domain steganographic algorithms. The basic idea behind the proposed method is twofold: The first is the capability of modeling linear dependencies of image rows/columns in local neighborhoods and the second is the normalization of different energy levels for different images. This idea is simply realized with integrating the logarithms of singular values calculated over image sub blocks resulting to a novel staganalyser, named as \"LogSv\". We consider three popular spatial domain steganographic algorithms; LSB, Hide4pgp, Steghide, five DCT domain steganographic algorithms; F5, Outguess, JP Hide&Seek, MB1, MB2 and PQ. Performance of the proposed method is compared with the state-of-the-art steganalysers.","Title: A tunable selective encryption scheme for H.264/AVC\nYear: 2013\n\nAbstract: In this paper a tunable selective encryption scheme for H.264/AVC is proposed to provide a tunable scrambling effect. The user can adjust the scrambling effect according to specifications of the application. Three kinds of syntax element are chosen to be encrypted: intra prediction modes, the sign bits of nonzero quantized DCT coefficients and the sign bits of motion vectors. The tunable feature is achieved by controlling the number of each kind of syntax element to be encrypted. To simplify the implementation and save the computational cost, a simple control mechanism is proposed to adjust the control factors. Experimental results show that the scrambling effect can be effectively adjusted with no or very minimal impact on the compression performance. The proposed scheme is secure against the replacement attack and the slight computational cost can meet real-time processing.","Title: A Corner Strength Based Fingerprint Segmentation Algorithm With Dynamic Thresholding\nYear: 2008\n\nAbstract: Segmentation is one of the first and most integral pre-processing steps for any Fingerprint Recognition System. It is used to identify the region of interest within an image. Performance of segmentation algorithms is dependent on the type of features and threshold values selected In this paper we propose a robust segmentation algorithm which utilizes the strength of Harris Corners for segmentation. The algorithm employs dynamic thresholding and simple binary operations to provide highly accurate segmentation of the image. Experimental results prove that the algorithm provides very accurate segmentation even for low quality images.","Title: A low complexity video watermarking in H.264 compressed domain\nYear: 2010\n\nAbstract: In this paper, a new blind and readable H.264 compressed domain watermarking scheme is proposed in which the embedding/extracting is performed using the syntactic elements of the compressed bit stream. As a result, it is not necessary to fully decode a compressed video stream both in the embedding and extracting processes. The method also presents an inexpensive spatiotemporal analysis that selects the appropriate submacroblocks for embedding, increasing watermark robustness while reducing its impact on visual quality. Meanwhile, the proposed method prevents bit-rate increase and restricts it within an acceptable limit by selecting appropriate quantized residuals for watermark insertion. Regarding watermarking demands such as imperceptibility, bit-rate control, and appropriate level of security, a priority matrix is defined which can be adjusted based on the application requirements. The resulted flexibility expands the usability of the proposed method.","Title: Unsupervised segmentation of multispectral images using edge progression and cost function\nYear: 2002\n\nAbstract: ABSTRACT This paper is concerned ,with the development ,of an unsupervised,segmentation ,algorithm ,for multispectral images. Due to the high dimensionality of these images, the underlining motivation of this work ,was on how ,to build up a ,robust unsupervised ,segmentation ,algorithm with acceptable computation ,complexity. After an initial approximate segmentation using EM algorithm, a cost function associated to each ,pixel is proposed. ,This function includes a term that measures how close the pixel athand is to region's distribution centroids, and another term,that measures ,the local homogeneity ,in pixel's neighborhood. In addition, an edge progression technique has been ,used to optimally ,re-label pixels. Extensive experiments have been carried out on many,multispectral images and quantitative results have shown,the efficiency of this approach.","Title: Accelerating The Computation Of Glcm And Haralick Texture Features On Reconfigurable Hardware\nYear: 2004\n\nAbstract: Grey Level Co-occurrence Matrix (GLCM), one of the best known tool for texture analysis, estimates image properties related to second-order statistics. These image properties commonly known as Haralick texture features can be used for image classification, image segmentation, and remote sensing applications. However, their computations are highly intensive especially for very large images such as medical ones. Therefore, methods to accelerate their computations are highly desired. This paper proposes the use of reconfigurable hardware to accelerate the calculation of GLCM and Haralick texture features. The performances of the proposed co-processor are then assessed and compared against a microprocessor based solution.","Title: Fingerprint - Iris Fusion Based Identification System Using a Single Hamming Distance Matcher\nYear: 2009\n\nAbstract: Conventional multimodal biometric identification systems tend to have larger memory footprint, slower processing speeds and a higher implementation and operational cost. In this paper we propose a state of the art framework for multimodal biometric identification system which can be adapted for any type of biometrics to provide smaller memory footprint and faster implementation than the conventional multimodal biometrics systems. The proposed framework is verified by development of a fingerprint and iris fusion system which utilizes a single Hamming Distance based matcher to provide higher accuracy than the individual unimodal system.","Title: An Evolutionary Snake Algorithm For The Segmentation Of Nuclei In Histopathological Images\nYear: 2004\n\nAbstract: This paper addresses the problem of automatic segmentation Of nuclei in histopathological images. A novel method, inspired from active contour models is proposed. An evolutionary based approach, which guarantees convergence to global minimum energies has been used to solve the combinatory optimization problem of snakes. The Computation complexity, often associated with evolutionary approaches, has been reduced by short cutting the natural evolution step by the mean of replacing standard Mutation with an oriented stochastic Mutation process. Results have shown the efficiency of this method both in terms of accuracy and fast computation.","Title: Partial encryption by randomized zig-zag scanning for video encoding\nYear: 2013\n\nAbstract: In this paper, a novel partial encryption method for video encoding is proposed. For video compression based on block transforms, two zig-zag scan orders can be used which provide similar compression performance. The proposed method involves randomly selecting one of these two scan orders. In addition, the sign bit of the DC coefficients can be flipped randomly and when employed with the proposed method provides a much better scrambling effect. In comparison to previous work in this area, experimental results based on H.264/AVC show that the proposed method can scramble the video with very minimal impact on the compression performance.","Title: A quadratic classifier based on multispectral texture features for prostate cancer diagnosis.\nYear: 2003\n\nAbstract: This paper is concerned with the development of an automatic classification system for use in Prostate cancer diagnosis. The system aims to detect and classify nuclei textures captured from microscopic samples taken from needle biopsies. The main contribution here is that the analysis is carried out over thirty three spectral bands instead of using the conventional grey scale or RGB colour spaces. A set of texture and morphological features has been computed for all these spectral bands for use in the discrimination phase. The large vector size has then been reduced to a manageable size by using a Principal Component Analysis. Classification tests have been carried out using Quadratic Discriminant Analysis and have shown that multispectral analysis significantly improves the overall classification performances when compared with the case where multispectral features are not considered.","Title: Simultaneous feature selection and feature weighting using Hybrid Tabu Search/K-nearest neighbor classifier\nYear: 2007\n\nAbstract: Feature selection and feature weighting are useful techniques for improving the classification accuracy of K-nearest-neighbor (K-NN) rule. The term feature selection refers to algorithms that select the best subset of the input feature set. In feature weighting, each feature is multiplied by a weight value proportional to the ability of the feature to distinguish pattern classes. In this paper, a novel hybrid approach is proposed for simultaneous feature selection and feature weighting of K-NN rule based on Tabu Search (TS) heuristic. The proposed TS heuristic in combination with K-NN classifier is compared with several classifiers on various available data sets. The results have indicated a significant improvement in the performance in classification accuracy. The proposed TS heuristic is also compared with various feature selection algorithms. Experiments performed revealed that the proposed hybrid TS heuristic is superior to both simple TS and sequential search algorithms. We also present results for the classification of prostate cancer using multispectral images, an important problem in biomedicine.","Title: Privacy region protection for H.264/AVC by encrypting the intra prediction modes without drift error in I frames\nYear: 2013\n\nAbstract: While video surveillance systems have become ubiquitous in our daily life, this has also brought some serious privacy concerns. Therefore, recent research in this area has included a focus on privacy region protection. Existing video scrambling techniques are being applied to specific regions of interest in a video while the background is left unchanged. In this paper, a new method involving the encryption of intra prediction modes (IPM) is proposed for privacy region protection without drift error in I frames. Compared with a previous technique that uses encryption of IPM, the proposed method offers savings in the bitrate overhead. To enhance the scrambling effect for the privacy region, the proposed method can support the combination of IPM with encryption of the sign bits of nonzero quantized transform coefficients in the privacy region. Experimental results and analysis based on H.264/AVC were carried out and verify the effectiveness of the proposed method.","Title: Color Cell Image Segmentation Using Pyramidal Constraint Satisfaction Neural Network\nYear: 1998\n\nAbstract: Automatic analysis of medical cell images has been gaining more importance in pharmacology and toxicology research. Segmentation of cell bodies is the crucial step in their analysis since result of segmentation directly affect the following quantitative analysis steps. On the other hand, various smoothing representations of cell bodies are desired to calculate different parameters of the cells. In this work, a new version the Constraint Satisfaction Neural Network (CSNN) algorithm is used to segment the cell images in various details. This is accomplished by incorporating in the CSNN algorithm a multiresolution scheme using pyramid structure.","Title: Foetal motion classification using optical flow displacement histograms\nYear: 2011\n\nAbstract: Foetal movement has been linked with foetal well-being. In the absence of medical input, its estimation depends exclusively on the mother's subjective opinion. Automatic classification of foetal movement from segmented two dimensional ultrasound scans is a step towards automatic estimation of foetal well-being through foetal motion evaluation. In this paper, optical flow displacement histograms are used to train a backpropagation neural network for classifying foetal movement by means of manually segmented frames that were evaluated independently by two medical experts. Results are promising towards developing an automated foetal motion analysis system but there is still the need for further testing of the hypothesis on a larger number of input samples.","Title: Partial palmprint matching using invariant local minutiae descriptors\nYear: 2010\n\nAbstract: In forensic investigations, it is common for forensic investigators to obtain a photograph of evidence left at the scene of crimes to aid them catch the culprit(s). Although, fingerprints are the most popular evidence that can be used, scene of crime officers claim that more than 30% of the evidence recovered from crime scenes originate from palms. Usually, palmprints evidence left at crime scenes are partial since very rarely full palmprints are obtained. In particular, partial palmprints do not exhibit a structured shape and often do not contain a reference point that can be used for their alignment to achieve efficient matching. This makes conventional matching methods based on alignment andminutiae pairing, as used in fingerprint recognition, to fail in partial palmprint recognition problems. In this paper a new partial-to-full palmprint recognition based on invariant minutiae descriptors is proposedwhere the partial palmprint's minutiae are extracted and considered as the distinctive and discriminating features for each palmprint image. This is achieved by assigning to eachminutiae a feature descriptor formed using the values of all the orientation histograms of the minutiae at hand. This allows for the descriptors to be rotation invariant and as such do not require any image alignment at the matching stage. The results obtained showthat the proposed technique yields a recognition rate of 99.2%. The solution does give a high confidence to the judicial jury in their deliberations and decision.","Title: Reversible watermarking using statistical information\nYear: 2010\n\nAbstract: In most reversible watermarking methods, a compressed locationmap is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.","Title: A novel prostate cancer classification technique using intermediate memory tabu search\nYear: 2005\n\nAbstract: The introduction of multispectral imaging in pathology problems such as the identification of prostatic cancer is recent. Unlike conventional RGB color space, it allows the acquisition of a large number of spectral bands within the visible spectrum. This results in a feature vector of size greater than 100. For such a high dimensionality, pattern recognition techniques suffer from the well-known curse of dimensionality problem. The two well-known techniques to solve this problem are feature extraction and feature selection. In this paper, a novel feature selection technique using tabu search with an intermediate-term memory is proposed. The cost of a feature subset is measured by leave-one-out correct-classification rate of a nearest-neighbor (1-NN) classifier. The experiments have been carried out on the prostate cancer textured multispectral images and the results have been compared with a reported classical feature extraction technique. The results have indicated a significant boost in the performance both in terms of minimizing features and maximizing classification accuracy.","Title: An FPGA Based Coprocessor for the Classification of Tissue Patterns in Prostatic Cancer\nYear: 2004\n\nAbstract: This paper discusses the suitability of reconfigurable, computing to speedup medical image classification problems. As an example of the speedup offered by reconfigurable logic, a multispectral computer vision system for automatic diagnosis of prostatic cancer is implemented. Different parallel architectures for various steps in automatic diagnosis are proposed and implemented in Field Programmable Gate Arrays (FPGAs). The first step of the algorithm is to compute Grey Level Co-occurrence Matrix (GLCM). The second step involves the normalisation of GLCM. The third step of the algorithm is to compute texture features from the normalised GLCM. The last step is concerned with image classification using linear discriminant analysis (LDA). Finally, the performance of the proposed system is assessed and compared against a microprocessor based solution. The results obtained clearly show that the proposed solution compares favorably.","Title: Adaptive binary mask for privacy region protection\nYear: 2012\n\nAbstract: Privacy region protection in video surveillance systems is an active topic at present. In previous research, a binary mask mechanism has been developed to indicate the privacy region; however this incurs a significant bitrate overhead. In this paper, an adaptive binary mask is proposed to represent the privacy region. In a practical privacy region protection application, in which the privacy region typically occupies less than half of the overall frame and is rectangular or approximately rectangular, the proposed adaptive binary mask can effectively reduce the bitrate overhead. The proposed method can also be easily applied to the FMO mechanism of H.264/AVC, providing both error resilience and a lower bitrate overhead.","Title: Spread Transform Watermarking for Digital Multimedia Using the Complex Wavelet Domain\nYear: 2007\n\nAbstract: Complex wavelets offer several improvements over their discretely sampled counterparts such as improved directionality and shift invariance allowing for better representation of image features. This has important implications for watermark embedding and modelling of the human visual system that is important to satisfy the imperceptibility requirement of watermarking systems. In addition spread transform watermarking has emerged as a method of combining the advantages of spread spectrum and quantization based data hiding algorithms, offering improved levels of capacity and robustness. This paper applies spread transform embedding and the complex wavelet domain to the case of grey scale, colour image and video watermarking.","Title: A new methodology in steganalysis: breaking highly undetectable steganograpy (HUGO)\nYear: 2011\n\nAbstract: This paper presents a new methodology for the steganalysis of digital images. In principle, the proposed method is applicable to any kind of steganography at any domain. Special interest is put on the steganalysis of Highly Undetectable Steganography (HUGO). The proposed method first extracts features via applying a function to the image, constructing the k variate probability density function (PDF) estimates, and downsampling it by a suitable downsampling algorithm. The extracted feature vectors are then further optimized in order to increase the detection performance and reduce the computational time. Finally using a supervised classification algorithm such as SVM, steganalysis is performed. The proposed method is capable of detecting BOSSRank image set with an accuracy of 85%.","Title: Image segmentation by relaxation using constraint satisfaction neural network\nYear: 2002\n\nAbstract: The problem of image segmentation using constraint satisfaction neural networks (CSNN) has been considered. Several variations of the CSNN theme have been advanced to improve its performance or to explore new structures. These new segmentation algorithms are based on interplay of additional constraints, of varying the organization of the network or modifying the relaxation scheme. The proposed schemes are tested comparatively on a bank of test images as well as real world images.","Title: SVD-Based Universal Spatial Domain Image Steganalysis\nYear: 2010\n\nAbstract: This paper is concerned with the universal (blind) image steganalysis problem and introduces a novel method to detect especially spatial domain steganographic methods. The proposed steganalyzer models linear dependencies of image rows/columns in local neighborhoods using singular value decomposition transform and employs content independency provided by a Wiener filtering process. Experimental results show that the novel method has superior performance when compared with its counterparts in terms of spatial domain steganography. Experiments also demonstrate the reasonable ability of the method to detect discrete cosine transform-based steganography as well as the perturbation quantization method.","Title: Palmprint Recognition Based on Subspace Analysis of Gabor Filter Bank\nYear: 2010\n\nAbstract: This paper introduces a new technique for palmprint recognition based on Fisher Linear Discriminant Analysis (FLDA) of Gabor filter bank. This method involves convolving a palmprint image with a bank of Gabor filters at different scales and rotations for robust palmprint features extraction. Once these feature are extracted, FLDA is applied for dimensionality reduction and class separability. Since the palmprint features are derived from the principal lines, wrinkles and texture along the palm area one should carefully consider this fact when selecting the appropriate palm region for feature extraction process in order to enhance recognition accuracy. To address this problem, an improved region of interest (ROI) extraction algorithm is introduced. This algorithm allows for an efficient extraction of the whole palm area ignoring all the undesirable parts, such as the fingers and background. Experiments have shown that the proposed method yields attractive performances evidence by an Equal Error Rate (EER) of 0.03%.","Title: Palmprint Recognition Based On Subspace Analysis Of Gabor Filter Bank\nYear: 2009\n\nAbstract: This paper introduces a new technique for palmprint recognition based on Fisher Linear Discriminant Analysis (FLDA) and Gabor filter bank. This method involves convolving a palmprint image with a bank of Gabor filters at different scales and rotations for robust palmprint features extraction. Once these features are extracted, FLDA is applied for dimensionality reduction and class separability. Since the palmprint features are derived from the principal lines, wrinkles and texture along the palm area. One should carefully consider this fact when selecting the appropriate palm region for the feature extraction process in order to enhance recognition accuracy. To address this problem, an improved region of interest (ROI) extraction algorithm is introduced. This algorithm allows for an efficient extraction of the whole palm area by ignoring all the undesirable parts, such as the fingers and background. Experiments have shown that the proposed method yields attractive performances as evidenced by an Equal Error Rate (EER) of 0.03%.","Title: SVD based image manipulation detection\nYear: 2010\n\nAbstract: In this paper we present a novel method based on singular value decomposition (SVD) for forensic analysis of digital images. We show that image tampering distorts linear dependencies of image rows/columns and derived features can be accurate enough to detect image manipulations and digital forgeries. Extensive experiments show that the proposed approach can outperform the counterparts in the literature.","Title: The improved sign bit encryption of motion vectors for H.264/AVC.\nYear: 2012\n\nAbstract: In this paper, an improved video encryption method for encrypting the sign bit of motion vectors is proposed based on H.264/AVC, which belongs to selective encryption. This method improves upon previous work involving the sign bit encryption of motion vectors by ensuring the four candidates for the encrypted motion vectors are always located in two orthogonal lines. The improved method can provide a much more effective scrambling effect while keeping the encrypted stream format-compliant and the compression ratio unchanged. The combination of the proposed method with encryption of intra prediction modes can further enhance the scrambling effect, especially for the first few frames which are left clear when only the motion vectors are encrypted.","Title: Robust Motion Detection via the Fuzzy Fusion of 6D Feature Space Decompositions\nYear: 2009\n\nAbstract: A change detection framework which fuses both spatial and temporal data using fuzzy if-then rules is presented. Temporal data is used on a per-pixel basis to monitor the sequence for changes by employing a fuzzy codebook model. Spatial data is gathered using a fuzzy multithresholding algorithm that decomposes the RGB color space into three color pair histograms. This system is found to be robust to noise and allows the algorithm to process successfully even when the underlying sequences result in under-segmentation of the spatial data.","Title: A Tunable Encryption Scheme and Analysis of Fast Selective Encryption for CAVLC and CABAC in H.264/AVC\nYear: 2013\n\nAbstract: Recently, two fast selective encryption methods for context-adaptive variable length coding and context-adaptive binary arithmetic coding in H.264/AVC were proposed by Shahid et. al. In this paper, it was demonstrated that these two methods are not as efficient as only encrypting the sign bits of nonzero coefficients. Experimental results showed that without encrypting the sign bits of nonzero coefficients, these two methods can not provide a perceptual scrambling effect. If a much stronger scrambling effect is required, intra prediction modes, and the sign bits of motion vectors can be encrypted together with the sign bits of nonzero coefficients. For practical applications, the required encryption scheme should be customized according to a user's specified requirement on the perceptual scrambling effect and the computational cost. Thus, a tunable encryption scheme combining these three methods is proposed for H.264/AVC. To simplify its implementation and reduce the computational cost, a simple control mechanism is proposed to adjust the control factors. Experimental results show that this scheme can provide different scrambling levels by adjusting three control factors with no or very little impact on the compression performance. The proposed scheme can run in real-time and its computational cost is minimal. The security of the proposed scheme is also discussed. It is secure against the replacement attack when all three control factors are set to one.","Title: JPEG Image Steganalysis Using Multivariate PDF Estimates With MRF Cliques\nYear: 2013\n\nAbstract: Blind steganalysis of JPEG images is addressed by modeling the correlations among the DCT coefficients using $K$ -variate $(K\\\\geq 2)$ p.d.f. estimates (p.d.f.s) constructed by means of Markov random field (MRF) cliques. The reasoning of using high variate p.d.f.s together with MRF cliques for image steganalysis is explained via a classical detection problem. Although our approach has many improvements over the current state-of-the-art, it suffers from the high dimensionality and the sparseness of the high variate p.d.f.s. The dimensionality problem as well as the sparseness problem are solved heuristically by means of dimensionality reduction and feature selection algorithms. The detection accuracy of the proposed method(s) is evaluated over Memon's (30.000 images) and Goljan's (1912 images) image sets. It is shown that practically applicable steganalysis systems are possible with a suitable dimensionality reduction technique and these systems can provide, in general, improved detection accuracy over the current state-of-the-art. Experimental results also justify this assertion.","Title: New FMO type to flag ROI in H.264/AVC\nYear: 2014\n\nAbstract: This paper presents a new type of Flexible Macroblock Ordering (FMO) type for the H.264 Advanced Video Coding (AVC) standard, which can more efficiently flag the position and shape of regions of interest (ROIs) in each frame. In H.264/AVC, 7 types of FMO have been defined, all of which are designed for error resilience. Most previous work related to ROI processing has adopted Type-2 (foreground & background), or Type-6 (explicit), to flag the position and shape of the ROI. However, only rectangular shapes are allowed in Type-2 and for non-rectangular shapes, the non-ROI macroblocks may be wrongly flagged as being within the ROI, which could seriously affect subsequent processing of the ROI. In Type-6, each macroblock in a frame uses fixed-length bits to indicate to its slice group. In general, each ROI is assigned to one slice group identity. Although this FMO type can more accurately flag the position and shape of the ROI, it incurs a significant bitrate overhead. The proposed new FMO type uses the smallest rectangle that covers the ROI to indicate its position and a spiral binary mask is employed within the rectangle to indicate the shape of the ROI. This technique can accurately flag the ROI and provide significantly savings in the bitrate overhead. Compared with Type-6, an 80% to 90% reduction in the bitrate overhead can be obtained while achieving the same accuracy.","Title: Colour image watermarking in the complex wavelet domain.\nYear: 2003\n\nAbstract: Digital image watermarking has become a very active research area. One key requirement in designing a watermarking system is that there should be no perceptible difference between the watermarked and original image, and the watermark should be difficult to remove or alter without damaging the host image. However, these two somewhat different requirements are usually closely related. This paper is concerned with an investigation of different methods to increase imperceptibility and robustness of colour watermarks embedded in colour host images using the Complex Wavelet Transform (CWT). The Complex Wavelet Transform was chosen because experimentation results from have shown the CWT to be more robust than other transforms under compression, additive noise, median and mean filtering attacks. Fusion based watermarking has been chosen since it provides a visual authentication of the watermark.","Title: An FPGA based co-processor for GLCM texture features measurement\nYear: 2003\n\nAbstract: Gray Level Co-occurrence Matrix (GLCM), one of the best known texture analysis methods, estimates image properties related to second-order statistics. These image properties commonly known as texture features can be used for image classification, image segmentation, and remote sensing applications. In this paper, we present an FPGA based co-processor to accelerate the extraction of texture features from GLCM. Handel-C, a recently developed C-like programming language for hardware design, has been used for the FPGA implementation of GLCM texture features measurement. Results show that the FPGA has better speed performances when compared to a general purpose processor for the extraction of GLCM features.","Title: Unsupervised histogram based color image segmentation.\nYear: 2003\n\nAbstract: In this paper, a new technique is proposed for the segmentation of color images. The technique is based on the use of the sigma filter and multithresholding of 2-band histograms. A sigma filter is first applied to smooth out regions while keeping edges. Histograms are then computed, smoothed and downsampled. A peak picking algorithm finds the predominant peaks in the histograms. A concordance process between the dominant peaks is performed to determine the corresponding peaks in the histograms. Labels are assigned to corresponding peaks. The resulting histograms are partitioned into regions having the right labels. The partitioned histograms are used to segment the R, G and B bands. Finally, the segmented bands are fused together to give the final segmented image.","Title: Comparison of different wavelet transforms for fusion based watermarking applications.\nYear: 2003\n\nAbstract: In this paper, we have investigated and assessed different wavelet transforms for use in fusion based watermarking applications. Scalar (discrete) wavelet, multiwavelet, complex wavelet and wavelet packet transforms have been studied to answer the following question: Which transform provides a better watermarking robustness given a certain imperceptibility factor? Fusion based watermarking has been chosen since it provides a visual authentication of the watermark. Perceptual embedding has been omitted to provide a fair comparison since different transforms have yielded different locations for the embedding process. It has been found that the CWT outperforms the other transforms while the WPT gives the worst results.","Title: A frontal view gait recognition based on 3D imaging using a time of flight camera\nYear: 2014\n\nAbstract: Studies have been carried out to recognize individuals from a frontal view using their gait patterns. In previous work, gait sequences were captured using either single or stereo RGB camera systems or the Kinect 1.0 camera system. In this research, we used a new frontal view gait recognition method using a laser based Time of Flight (ToF) camera. In addition to the new gait data set, other contributions include enhancement of the silhouette segmentation, gait cycle estimation and gait image representations. We propose four new gait image representations namely Gait Depth Energy Image (GDE), Partial GDE (PGDE), Discrete Cosine Transform GDE (DGDE) and Partial DGDE (PDGDE). The experimental results show that all the proposed gait image representations produce better accuracy than the previous methods. In addition, we have also developed Fusion GDEs (FGDEs) which achieve better overall accuracy and outperform the previous methods.","Title: Data cleaning and outlier removal: Application in human skin detection\nYear: 2014\n\nAbstract: An outlier removal based data cleaning technique is proposed to clean manually pre-segmented human skin data in colour images. The 3-dimensional colour data is projected onto three 2-dimensional planes, from which outliers are removed. The cleaned 2 dimensional data projections are merged to yield a 3D clean RGB data. This data is finally used to build a look up table and a single Gaussian classifier for the purpose of human skin detection in colour images.","Title: Detecting packed executables using steganalysis\nYear: 2014\n\nAbstract: This paper proposes a novel method of detecting packed executable files using steganalysis, primarily targeting the detection of obfuscated malware through packing. Considering that over 80% of malware in the wild is packed, detection accuracy and low false negative rates are important properties of malware detection methods. Experimental results outlined in this paper reveal that the proposed approach achieving an overall detection accuracy of greater than 99%, a false negative rate of 1% and a false positive rate of 0%.","Title: An improved wavelet-based image watermarking technique\nYear: 2005\n\nAbstract: This paper proposes an adaptive blind image watermarking technique based on wavelet transform using a random sequence of real numbers. First, the image is decomposed into non overlapping blocks. Then, each block is classified as uniform or non uniform by using a JND-based classifier. The strength of the embedded watermark into the high subband coefficients of each transformed block depends upon the nature of the block according to its classification. The Neyman-Pearson criterion is used to derive the detection rule. Unlike the embedding process, the detection does not require any classification of blocs. This adaptive approach has been assessed on various standard images and compared with a similar watermarking technique (H. Inoue et al., 1999). The results have shown an obvious improvement in terms of robustness against different manipulations and a better ability of detection","Title: On the Optimum Multiplicative Watermark Detection in the Transform Domain\nYear: 2006\n\nAbstract: ABSTRACT This paper presents an investigation on the optimum,detection of multiplicative watermarks,based on statistical behaviour of image contents in the transform domain. In recent works, the problem of watermark,detection is viewed,as a binary decision where the ob- servation is the possibly watermarked,transformed coefficients. In- deed, the detector verifies whether the watermark presented to its in- put is actually embedded,in the input image (hypothesis H1) or not (hypothesis H0). Such a detection scheme,relies on the Neyman- Pearson criterion to derive a decision threshold by minimising,the probability of missed detection with respect to a given probability of false alarm. Previous works approximate,the probability density function (pdf) of the observation when hypothesis H0 holds by the pdf when,hypothesis of having no watermark,embedded,in the input image is in force by assuming,that the watermark,strength is weak to some extent. However, the weakness of the watermark does fulfil the requirement on the robustness. Moreover, from the viewpoint of the decision theory, the smaller the embedding depth, the worse the watermark,detection. This paper describes the drawback,behind this approximation,in the general case and proposes an efficient so- lution closer to the theoretical derivation. To validate the proposed technique, we consider a special case in which the Laplace statistical model is used. Index Terms— Image watermarking, multiplicative watermark,","Title: A Robust Blind Image Watermarking Scheme in the SPIHT-Compressed Bit-Stream\nYear: 2006\n\nAbstract: Practical digital multimedia is usually encountered in compressed format, and as such it is highly desirable to develop watermarking algorithms that operate totally in the compressed domain. In addition, watermarking schemes working jointly with SNR-scalable compression algorithms would be of great interest since the watermarks could be entirely retrieved at a given bit-rate. In this context, this paper proposes a robust blind image watermarking scheme operating in the SPIHT-compressed bit-stream. First, the watermark, which is a binary sequence, is encoded with an error-correction coding and interleaved to minimize the error decoding probability and combat bursts of errors. Then, in the course of SPIHT encoding process, the list of significant pixels (LSP) is used to embed the watermark sequence in a uniform quantisation manner at a given threshold where the coefficients of interest are differently refined in the next passes. Experimental results, carried out on various images, have shown the robustness of the watermark in the presence of different attacks.","Title: Robust motion detection by fusion of 6D feature space decompositions\nYear: 2008\n\nAbstract: ABSTRACT Amotion,detection framework ,is presented ,that integrates spatial and temporal data by decomposition, of ,the feature space. Temporal data is employed to monitor frame changes on a per-pixel basis, whilst the spatial data is used to provide region-based segmentation of image frames. The thresholded difference image from the change detection is then ,fused with the segmented ,image. It is found that this framework greatly improves robustness to noise, while retaining and, in some cases, improving the sensitivity to regions of interest. Further, the decomposition reduces the time required to run due to the reduction in computationalcomplexity. Index Terms— Image motion analysis, Image segmentation 1. INTRODUCTION CCTV cameras ,have found their way ,into almost every public space outside the home ,in the ,UK. Due to this ubiquity the sheer volume ,of data ,gathered has become unwieldy,from a manual ,analysis viewpoint. A potential cost-effective solution to this ,problem ,is the ,use of automated analysis software. The,first step in such systems isthat of motion ,or foreground ,detection. There has been much work done in this area, and there is a growing acceptance,within the community ,that this is a ,solved","Title: Paralysis: An Extensible Multi-tiered Guidance Environment for Program Parallelization and Analysis\nYear: 2013\n\nAbstract: The heterogeneous computing revolution continues unabated. Yet despite the vast number of naïve users in possession of bespoke software hoping to embrace the opportunities that this revolution has wrought, few approaches proposed in current literature can guide such users in these efforts. The most appropriate choice would appear to be a (semi-)automating compiler. However, these typically target a single device-type and demand the unguided use of directives. Consequently, they are of little use when naïve users are seeking answers to more fundamental questions, such as: which fragments of a program can/should be parallelized, which device should each fragment target, and what speedup will be attained. To this end, this paper expands on previous work and proposes Paralysis - an extensible guidance environment, tiered for varying programmer competencies with support for static and dynamic analysis techniques. At the highest level, guided user experiences are paramount. At the lowest level, underlying functionality is exposed as a set of plug-ins, ensuring longevity. A partial prototype, built atop the Cetus infrastructure, is described. It is used to analyze two serial programs for CUDA execution - the DFT and the Box Blur Filter. Speedups of 15x and 22x are achieved on the basis of the analysis.","Title: Video steganalysis of LSB based motion vector steganography\nYear: 2013\n\nAbstract: This paper proposes a novel flatness measure for video steganalysis targeting LSB based motion vector steganography. The proposed method has introduced two major improvements. Firstly, unlike previous approaches, it takes into account the anchor frame and current frame distances and directions, which significantly affect the correlation strength of adjacent motion vectors. Secondly, it defines a cover model that does not require a training based machine learning system. Large amounts of videos including broad range of motion patterns have been used in order to approximate the real detection rate of the proposed method. Test results show that proposed algorithm successfully classifies cover and stego videos.","Title: Perceptual watermarking for Discrete Shearlet transform\nYear: 2014\n\nAbstract: This paper presents a new perceptual watermarking model for Discrete Shearlet transform (DST). DST provides the optimal representation [10] of the image features based on multi-resolution and multi-directional analysis. This property can be exploited on for watermark embedding to achieve the watermarking imperceptibility by introducing the human visual system using Chou's model. In this model, a spatial JND profile is adapted to fit the sub-band structure. The combination of DST and the Just-Noticeable Distortion (JND) profile improves the levels of robustness against certain attacks while minimizing the distortion; by assigning a visibility threshold of distortion to each DST sub-band coefficient in the case of grey scale image watermarking.","Title: A scalable SPIHT-based multispectral image compression technique\nYear: 2006\n\nAbstract: This paper addresses the compression of multispectral im- ages which can be viewed, at the encoder side, as a three- dimensional (3D) data set characterized by a high correlation through the successive bands. Recently, the celebrated 3D- SPIHT (Sets Partitioning In Hierarchical Trees) algorithm has been widely adopted in the literature for the coding of mul- tispectral images because of its proven state-of-the art per- formance. In order to exploit the spectral redundancy in the 3D wavelet transform domain, a new scalable SPIHT based multispectral image compression technique is proposed. The rational behind this approach is that image components in two consecutive transformed bands are significantly dependent in terms of zerotrees locations in the 3D-DWT domain. There- fore, by joining the trees with the same location into the List of Insignificant Sets (LIS), a considerable amount of bits can be reduced in the sorting pass in comparison with the separate encoding of the transformed bands. Numerical experiments on two sample multispectral images show a highly better per- formance of the proposed technique when compared to the conventional 3D-SPIHT. Currently, with the huge advance in the use and distribu- tion of digital multimedia data, the transmission and delivery of massively large images over heterogeneous data networks has turned out to be a real preoccupation for an increasing number of researchers in the field of image compression. Sat- isfying the requests in terms of image quality under the con- straint of the diversity of the traffic on the network is a real issue. Since the server must satisfy the users having both high and low bandwidth simultaneously, a straightforward solution to the problem is to compress and store the encoded version of the image data at different bit-rates. However, this approach involves providing the server with a large disk space and a management system for the stored data. Therefore, scalabil- ity, the capability of decoding a compressed image at different bit-rates, provides an attractive solution, allowing only one encoded image version to be stored in the database thereby avoiding the overhead of maintaining several versions of the coded data at various bit rates. In rate scalable coding, all of the compressed data is embedded in a single bit stream which can be decoded at different bit-rates. The decompression al- gorithm receives and decodes the compressed data from the start of the bit stream until a desired data rate is achieved.","Title: Spread transform video watermarking using 3D complex wavelets\nYear: 2007\n\nAbstract: A novel video watermarking system is presented that uses a spread transform technique to securely embed data into a video sequence, resistant to both spatial and temporal attacks. The system makes use of the 3-D wavelet domain, improving embedding by extending this to include complex as well as discretely sampled wavelet transforms. To ensure imperceptibility an adaptation of a proven video visual model is used. Results are given for both compression and frame dropping attacks.","Title: Colour spread transform data hiding capacity using complex wavelets\nYear: 2007\n\nAbstract: Information theoretic methods of calculating the capacity of data hiding schemes allow for objective comparisons of watermarking algorithms. This paper applies these methods to the case of colour image watermarking, using a dual tree complex wavelet transform and non redundant complex wavelet transform along with a spread transform data hiding algorithm to compare levels of capacity between the two most commonly used uncorrelated colour spaces. The information theoretic model used involves the use of game theory applied to optimize the embedding and attack strategy across parallel Gaussian channels. The two most popular uncorrelated colour spaces YUV and YIQ are compared.","Title: A novel modality independent score-level quality measure\nYear: 2010\n\nAbstract: The performance of biometric systems deployed in real world scenarios is affected adversely by the degradation in the input quality. This degradation can take place either in the input or due to inherent design of the deployed system. Quality Measures aim to provide a quantitative indication of this degradation which can be utilized to help access the probability that the provided biometric decision is correct. In this paper we present a novel, modality independent, score level quality measure based on Mahalanobis Distance. This measure exploits the inter-dependencies which exist between the data and matching score to reduce the error rates and improve the performance of the deployed biometric system. The effectiveness of the proposed approach is verified by extensive testing using the standard databases available of fingerprints and Iris data.","Title: Privacy region protection for H.264/AVC with enhanced scrambling effect and a low bitrate overhead.\nYear: 2015\n\nAbstract: While video surveillance systems have become ubiquitous in our daily lives, they have introduced concerns over privacy invasion. Recent research to address these privacy issues includes a focus on privacy region protection, whereby existing video scrambling techniques are applied to specific regions of interest (ROI) in a video while the background is left unchanged. Most previous work in this area has only focussed on encrypting the sign bits of nonzero coefficients in the privacy region, which produces a relatively weak scrambling effect. In this paper, to enhance the scrambling effect for privacy protection, it is proposed to encrypt the intra prediction modes (IPM) in addition to the sign bits of nonzero coefficients (SNC) within the privacy region. A major issue with utilising encryption of IPM is that drift error is introduced outside the region of interest. Therefore, a re-encoding method, which is integrated with the encryption of IPM, is also proposed to remove drift error. Compared with a previous technique that uses encryption of IPM, the proposed re-encoding method offers savings in the bitrate overhead while completely removing the drift error. Experimental results and analysis based on H.264/AVC were carried out to verify the effectiveness of the proposed methods. In addition, a spiral binary mask mechanism is proposed that can reduce the bitrate overhead incurred by flagging the position of the privacy region. A definition of the syntax structure for the spiral binary mask is given. As a result of the proposed techniques, the privacy regions in a video sequence can be effectively protected by the enhanced scrambling effect with no drift error and a lower bitrate overhead.","Title: AN FPGA BASED PARAMETRISABLE SYSTEM FOR DISCRETE ORTHOGONAL TRANSFORMS IMPLEMENTATION\nYear: 2002\n\nAbstract: This paper presents novel architectures for efficient implementation of Discrete Orthogonal Transforms (DOTs) using an FPGA based parameterisable system. These transforms are important in many signal and image processing applications including image and speech compression, filtering and coding. Two novel architectures for DOTs using both systolic architecture and distributed arithmetic design methodologies are presented. The first approach uses the Modified Booth-encoder-Wallace trees Multiplication (MBWM) algorithm for a systolic architecture implementation. The second approach is based on both distributed arithmetic ROM and accumulator structure, and Offset Binary Coding technique (OBC). Implementations of the algorithms on a Xilinx FPGA board are described. Distributed arithmetic approach exhibits better performances when compared with the systolic architecture approach.","Title: Spatio-Temporal Rich Model For Motion Vector Steganalysis\nYear: 2015\n\nAbstract: We propose a spatio-temporal rich model of motion vector planes as a part of a full steganalytic system against motion vector based steganography. Superior detection accuracy of the rich model over the previous methods has been lately demonstrated for digital images in both spatial and DCT domain. It has not been heretofore used for detection of motion vector steganography. We also introduced a transformation so as to extend the feature set with temporal residuals. We carried out the tests along with most recent motion vector steganalysis and steganography methods. Test results show that the proposed model delivers an outstanding performance compared to the previous methods.","Title: Spatio-Temporal Rich Model-Based Video Steganalysis on Cross Sections of Motion Vector Planes.\nYear: 2016\n\nAbstract: A rich model-based motion vector (MV) steganalysis benefiting from both temporal and spatial correlations of MVs is proposed in this paper. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this paper. First, it is shown that there i...","Title: Video authentication based on statistical local information.\nYear: 2016\n\nAbstract: With the outgrowth of video editing tools, video information trustworthiness becomes a hypersensitive field. Today many devices have the capability of capturing digital videos such as CCTV, digital cameras and mobile phones and these videos may transmitted over the Internet or any other non secure channel. As digital video can be used to as supporting evidence, it has to be protected against manipulation or tampering. As most video authentication techniques are based on watermarking and digital signatures, these techniques are effectively used in copyright purposes but difficult to implement in other cases such as video surveillance or in videos captured by consumer's cameras. In this paper we propose an intelligent technique for video authentication which uses the video local information which makes it useful for real world applications. The proposed algorithm relies on the video's statistical local information which was applied on a dataset of videos captured by a range of consumer video cameras. The results show that the proposed algorithm has potential to be a reliable intelligent technique in digital video authentication without the need to use for SVM classifier which makes it faster and less computationally expensive in comparing with other intelligent techniques.","Title: Frontal View Gait Recognition With Fusion of Depth Features From a Time of Flight Camera.\nYear: 2019\n\nAbstract: Frontal view gait recognition for people identification has been carried out using single RGB, stereo RGB, Kinect 1.0, and Doppler radar. However, existing methods based on these camera technologies suffer from several problems. Therefore, we propose a four-part method for frontal view gait recognition based on the fusion of multiple features acquired from a Time-of-Flight (ToF) camera. We have de...","Title: Man-In-The-Middle Attacks in Vehicular Ad-Hoc Networks: Evaluating the Impact of Attackers' Strategies.\nYear: 2018\n\nAbstract: Vehicular Ad-Hoc Network (VANET), a vital component of Intelligent Transportation Systems (ITS) technology, relies on communication between dynamically connected vehicles and static Road Side Units (RSU) to offer various applications (e.g., collision avoidance alerts, steep-curve warnings and infotainment). VANET has a massive potential to improve traffic efficiency, and road safety by exchanging critical information between nodes (vehicles and RSU), thus reducing the likelihood of traffic accidents. However, this communication between nodes is subject to a variety of attacks, such as Man-In-The-Middle (MITM) attacks which represent a major risk in VANET. It happens when a malicious node intercepts or tampers with messages exchanged between legitimate nodes. In this paper, we studied the impact on network performance of different strategies which attackers can adopt to launch MITM attacks in VANET, such as fleet or random strategies. In particular, we focus on three goals of MITM attacks-message delayed, message dropped and message tampered. The simulation results indicate that these attacks have a severe influence on the legitimate nodes in VANET as the network experience high number of compromised messages, high end-to-end delays and preeminent packet losses.","Title: Blind Image Watermark Detection Algorithm Based on Discrete Shearlet Transform Using Statistical Decision Theory.\nYear: 2018\n\nAbstract: Blind watermarking targets the challenging recovery of the watermark when the host is not available during the detection stage. This paper proposes Discrete Shearlet Transform (DST) as a new embedding domain for blind image watermarking. Our novel DST blind watermark detection system uses a nonadditive scheme based on the statistical decision theory. It first computes the Probability Density Funct...","Title: A Comparative Analysis of Trust Models for Safety Applications in IoT-enabled Vehicular Networks\nYear: 2019\n\nAbstract: Vehicular Ad-hoc NETwork (VANET) is a vital transportation technology that facilitates the vehicles to share sensitive information (such as steep-curve warnings and black ice on the road) with each other and with the surrounding infrastructure in real-time to avoid accidents and enable comfortable driving experience.To achieve these goals, VANET requires a secure environment for authentic, reliable and trusted information dissemination among the network entities. However, VANET is prone to different attacks resulting in the dissemination of compromised/false information among network nodes. One way to manage a secure and trusted network is to introduce trust among the vehicular nodes. To this end, various Trust Models (TMs) are developed for VANET and can be broadly categorized into three classes, Entity-oriented Trust Models (ETM), Data oriented Trust Models (DTM) and Hybrid Trust Models (HTM). These TMs evaluate trust based on the received information (data), the vehicle (entity) or both through different mechanisms. In this paper, we present a comparative study of the three TMs. Furthermore, we evaluate these TMs against the different trust, security and quality-of-service related benchmarks. Simulation results revealed that all these TMs have deficiencies in terms of end-to-end delays, event detection probabilities and false positive rates. This study can be used as a guideline for researchers to design new efficient and effective TMs for VANET.","Title: Realization of Blockchain in Named Data Networking-Based Internet-of-Vehicles\nYear: 2019\n\nAbstract: The revolution of Internet-of-vehicles (IoV) has stimulated a substantial response from academia, research, and industry due to its massive potential to improve overall transportation. Current IoV faces huge challenges due to its reliance on IP-based network architecture. Therefore, named data networking (NDN) is proposed as a promising architecture to solve issues posed by IP-based systems. Recently, blockchains (BCs) have been utilized within IoV to increase network security. However, the integration of BC within NDN-enabled IoV is still an open research problem. In this study, we proposed a novel tier-based architecture known as “Blockchain in NDN-enabled Internet-of-vehicles (BINDN),” which can support BC within NDN-enabled IoV. BINDN can be used as reference architecture to design security solutions in NDN-enabled IoV using BC. Furthermore, it provides an extensive set of applications including IoV security, trust management, and privacy enhancements. Moreover, we highlighted major challenges and issues when integrating BC within NDN-enabled IoV.","Title: A Survey of Deep Learning Solutions for Multimedia Visual Content Analysis.\nYear: 2019\n\nAbstract: The increasing use of social media networks on handheld devices, especially smartphones with powerful built-in cameras, and the widespread availability of fast and high bandwidth broadband connections, added to the popularity of cloud storage, is enabling the generation and distribution of massive volumes of digital media, including images and videos. Such media is full of visual information and holds immense value in today's world. The volume of data involved calls for automated visual content analysis systems able to meet the demands of practice in terms of efficiency and effectiveness. Deep learning (DL) has recently emerged as a prominent technique for visual content analysis. It is data-driven in nature and provides automatic end-to-end learning solutions without the need to rely explicitly on predefined handcrafted feature extractors. Another appealing characteristic of DL solutions is the performance they can achieve, once the network is trained, under practical constraints. This paper identifies eight problem domains which require analysis of visual artifacts in multimedia. It surveys the recent, authoritative, and the best performing DL solutions and lists the datasets used in the development of these deep methods for the identified types of visual analysis problems. This paper also discusses the challenges that the DL solutions face which can compromise their reliability, robustness, and accuracy for visual content analysis.","Title: A Novel Security Methodology For Smart Grids: A Case Study Of Microcomputer-Based Encryption For Pmu Devices\nYear: 2021\n\nAbstract: Coordination of a power system with the phasor measurement devices (PMUs) in real time on the load and generation sides is carried out within the context of smart grid studies. Power systems equipped with information systems in a smart grid pace with external security threats. Developing a smart grid which can resist against cyber threats is considered indispensable for the uninterrupted operation. In this study, a two-way secure communication methodology underpinned by a chaos-based encryption algorithm for PMU devices is proposed. The proposed system uses the IEEE-14 busbar system on which the optimum PMU placement has been installed. The proposed hyperchaotic system-based encryption method is applied as a new security methodology among PMU devices. The success of results is evaluated by the completeness of data exchange, durations, the complexity of encryption-decryption processes, and strength of cryptography using a microcomputer-based implementation. The results show that the proposed microcomputer-based encryption algorithms can be directly embedded as encryption hardware units into PMU and PDC devices which have very fast signal processing capabilities taking into considerations the acceptable delay time for power system protection and measuring applications and quality metering applications which is 2 ms and 10 ms, respectively. While proposed algorithms can be used in TCP or UDP over IP-based IEEE C37.118, IEC 61850, and IEC 61850-90-5 communication frameworks, they can also be embedded into electronic cards, smartcards, or smart tokens which are utilized for authentication among smart grid components."],"string":"[\n \"Title: Eigenspectra Palmprint Recognition\\nYear: 2008\\n\\nAbstract: This paper proposes a novel technique for palmprint recognition in the transform domain and based on a combination of Principal Component Analysis (PCA) and Fourier transform. Although, PCA is widely adopted as one of the most promising tools for use in biometric recognition systems, it comes with its own limitations: poor discriminating power in the presence of variant illuminations, requires a large computational load when the original dimensionality of data is high while the number of training samples is usually large. Traditionally, to represent the palmprint image, PCA is carried out on the whole spatial image. In the proposed method, Fourier transform is used to decompose an image into its sine and cosine components, then the spectrum is used for PCA representation since doing PCA on the whole frequency domain does not achieve any performance improvements. In comparison with the traditional PCA and three other methods, the proposed method yields better recognition accuracy and discriminating. In addition, the proposed method reduces the computational load significantly to half due to the symmetry property of Fourier transform.\",\n \"Title: A novel universal steganalyser design: “LogSv”\\nYear: 2009\\n\\nAbstract: This paper introduces a novel universal steganalysis method in order to attack especially spatial domain steganographic algorithms. The basic idea behind the proposed method is twofold: The first is the capability of modeling linear dependencies of image rows/columns in local neighborhoods and the second is the normalization of different energy levels for different images. This idea is simply realized with integrating the logarithms of singular values calculated over image sub blocks resulting to a novel staganalyser, named as \\\"LogSv\\\". We consider three popular spatial domain steganographic algorithms; LSB, Hide4pgp, Steghide, five DCT domain steganographic algorithms; F5, Outguess, JP Hide&Seek, MB1, MB2 and PQ. Performance of the proposed method is compared with the state-of-the-art steganalysers.\",\n \"Title: A tunable selective encryption scheme for H.264/AVC\\nYear: 2013\\n\\nAbstract: In this paper a tunable selective encryption scheme for H.264/AVC is proposed to provide a tunable scrambling effect. The user can adjust the scrambling effect according to specifications of the application. Three kinds of syntax element are chosen to be encrypted: intra prediction modes, the sign bits of nonzero quantized DCT coefficients and the sign bits of motion vectors. The tunable feature is achieved by controlling the number of each kind of syntax element to be encrypted. To simplify the implementation and save the computational cost, a simple control mechanism is proposed to adjust the control factors. Experimental results show that the scrambling effect can be effectively adjusted with no or very minimal impact on the compression performance. The proposed scheme is secure against the replacement attack and the slight computational cost can meet real-time processing.\",\n \"Title: A Corner Strength Based Fingerprint Segmentation Algorithm With Dynamic Thresholding\\nYear: 2008\\n\\nAbstract: Segmentation is one of the first and most integral pre-processing steps for any Fingerprint Recognition System. It is used to identify the region of interest within an image. Performance of segmentation algorithms is dependent on the type of features and threshold values selected In this paper we propose a robust segmentation algorithm which utilizes the strength of Harris Corners for segmentation. The algorithm employs dynamic thresholding and simple binary operations to provide highly accurate segmentation of the image. Experimental results prove that the algorithm provides very accurate segmentation even for low quality images.\",\n \"Title: A low complexity video watermarking in H.264 compressed domain\\nYear: 2010\\n\\nAbstract: In this paper, a new blind and readable H.264 compressed domain watermarking scheme is proposed in which the embedding/extracting is performed using the syntactic elements of the compressed bit stream. As a result, it is not necessary to fully decode a compressed video stream both in the embedding and extracting processes. The method also presents an inexpensive spatiotemporal analysis that selects the appropriate submacroblocks for embedding, increasing watermark robustness while reducing its impact on visual quality. Meanwhile, the proposed method prevents bit-rate increase and restricts it within an acceptable limit by selecting appropriate quantized residuals for watermark insertion. Regarding watermarking demands such as imperceptibility, bit-rate control, and appropriate level of security, a priority matrix is defined which can be adjusted based on the application requirements. The resulted flexibility expands the usability of the proposed method.\",\n \"Title: Unsupervised segmentation of multispectral images using edge progression and cost function\\nYear: 2002\\n\\nAbstract: ABSTRACT This paper is concerned ,with the development ,of an unsupervised,segmentation ,algorithm ,for multispectral images. Due to the high dimensionality of these images, the underlining motivation of this work ,was on how ,to build up a ,robust unsupervised ,segmentation ,algorithm with acceptable computation ,complexity. After an initial approximate segmentation using EM algorithm, a cost function associated to each ,pixel is proposed. ,This function includes a term that measures how close the pixel athand is to region's distribution centroids, and another term,that measures ,the local homogeneity ,in pixel's neighborhood. In addition, an edge progression technique has been ,used to optimally ,re-label pixels. Extensive experiments have been carried out on many,multispectral images and quantitative results have shown,the efficiency of this approach.\",\n \"Title: Accelerating The Computation Of Glcm And Haralick Texture Features On Reconfigurable Hardware\\nYear: 2004\\n\\nAbstract: Grey Level Co-occurrence Matrix (GLCM), one of the best known tool for texture analysis, estimates image properties related to second-order statistics. These image properties commonly known as Haralick texture features can be used for image classification, image segmentation, and remote sensing applications. However, their computations are highly intensive especially for very large images such as medical ones. Therefore, methods to accelerate their computations are highly desired. This paper proposes the use of reconfigurable hardware to accelerate the calculation of GLCM and Haralick texture features. The performances of the proposed co-processor are then assessed and compared against a microprocessor based solution.\",\n \"Title: Fingerprint - Iris Fusion Based Identification System Using a Single Hamming Distance Matcher\\nYear: 2009\\n\\nAbstract: Conventional multimodal biometric identification systems tend to have larger memory footprint, slower processing speeds and a higher implementation and operational cost. In this paper we propose a state of the art framework for multimodal biometric identification system which can be adapted for any type of biometrics to provide smaller memory footprint and faster implementation than the conventional multimodal biometrics systems. The proposed framework is verified by development of a fingerprint and iris fusion system which utilizes a single Hamming Distance based matcher to provide higher accuracy than the individual unimodal system.\",\n \"Title: An Evolutionary Snake Algorithm For The Segmentation Of Nuclei In Histopathological Images\\nYear: 2004\\n\\nAbstract: This paper addresses the problem of automatic segmentation Of nuclei in histopathological images. A novel method, inspired from active contour models is proposed. An evolutionary based approach, which guarantees convergence to global minimum energies has been used to solve the combinatory optimization problem of snakes. The Computation complexity, often associated with evolutionary approaches, has been reduced by short cutting the natural evolution step by the mean of replacing standard Mutation with an oriented stochastic Mutation process. Results have shown the efficiency of this method both in terms of accuracy and fast computation.\",\n \"Title: Partial encryption by randomized zig-zag scanning for video encoding\\nYear: 2013\\n\\nAbstract: In this paper, a novel partial encryption method for video encoding is proposed. For video compression based on block transforms, two zig-zag scan orders can be used which provide similar compression performance. The proposed method involves randomly selecting one of these two scan orders. In addition, the sign bit of the DC coefficients can be flipped randomly and when employed with the proposed method provides a much better scrambling effect. In comparison to previous work in this area, experimental results based on H.264/AVC show that the proposed method can scramble the video with very minimal impact on the compression performance.\",\n \"Title: A quadratic classifier based on multispectral texture features for prostate cancer diagnosis.\\nYear: 2003\\n\\nAbstract: This paper is concerned with the development of an automatic classification system for use in Prostate cancer diagnosis. The system aims to detect and classify nuclei textures captured from microscopic samples taken from needle biopsies. The main contribution here is that the analysis is carried out over thirty three spectral bands instead of using the conventional grey scale or RGB colour spaces. A set of texture and morphological features has been computed for all these spectral bands for use in the discrimination phase. The large vector size has then been reduced to a manageable size by using a Principal Component Analysis. Classification tests have been carried out using Quadratic Discriminant Analysis and have shown that multispectral analysis significantly improves the overall classification performances when compared with the case where multispectral features are not considered.\",\n \"Title: Simultaneous feature selection and feature weighting using Hybrid Tabu Search/K-nearest neighbor classifier\\nYear: 2007\\n\\nAbstract: Feature selection and feature weighting are useful techniques for improving the classification accuracy of K-nearest-neighbor (K-NN) rule. The term feature selection refers to algorithms that select the best subset of the input feature set. In feature weighting, each feature is multiplied by a weight value proportional to the ability of the feature to distinguish pattern classes. In this paper, a novel hybrid approach is proposed for simultaneous feature selection and feature weighting of K-NN rule based on Tabu Search (TS) heuristic. The proposed TS heuristic in combination with K-NN classifier is compared with several classifiers on various available data sets. The results have indicated a significant improvement in the performance in classification accuracy. The proposed TS heuristic is also compared with various feature selection algorithms. Experiments performed revealed that the proposed hybrid TS heuristic is superior to both simple TS and sequential search algorithms. We also present results for the classification of prostate cancer using multispectral images, an important problem in biomedicine.\",\n \"Title: Privacy region protection for H.264/AVC by encrypting the intra prediction modes without drift error in I frames\\nYear: 2013\\n\\nAbstract: While video surveillance systems have become ubiquitous in our daily life, this has also brought some serious privacy concerns. Therefore, recent research in this area has included a focus on privacy region protection. Existing video scrambling techniques are being applied to specific regions of interest in a video while the background is left unchanged. In this paper, a new method involving the encryption of intra prediction modes (IPM) is proposed for privacy region protection without drift error in I frames. Compared with a previous technique that uses encryption of IPM, the proposed method offers savings in the bitrate overhead. To enhance the scrambling effect for the privacy region, the proposed method can support the combination of IPM with encryption of the sign bits of nonzero quantized transform coefficients in the privacy region. Experimental results and analysis based on H.264/AVC were carried out and verify the effectiveness of the proposed method.\",\n \"Title: Color Cell Image Segmentation Using Pyramidal Constraint Satisfaction Neural Network\\nYear: 1998\\n\\nAbstract: Automatic analysis of medical cell images has been gaining more importance in pharmacology and toxicology research. Segmentation of cell bodies is the crucial step in their analysis since result of segmentation directly affect the following quantitative analysis steps. On the other hand, various smoothing representations of cell bodies are desired to calculate different parameters of the cells. In this work, a new version the Constraint Satisfaction Neural Network (CSNN) algorithm is used to segment the cell images in various details. This is accomplished by incorporating in the CSNN algorithm a multiresolution scheme using pyramid structure.\",\n \"Title: Foetal motion classification using optical flow displacement histograms\\nYear: 2011\\n\\nAbstract: Foetal movement has been linked with foetal well-being. In the absence of medical input, its estimation depends exclusively on the mother's subjective opinion. Automatic classification of foetal movement from segmented two dimensional ultrasound scans is a step towards automatic estimation of foetal well-being through foetal motion evaluation. In this paper, optical flow displacement histograms are used to train a backpropagation neural network for classifying foetal movement by means of manually segmented frames that were evaluated independently by two medical experts. Results are promising towards developing an automated foetal motion analysis system but there is still the need for further testing of the hypothesis on a larger number of input samples.\",\n \"Title: Partial palmprint matching using invariant local minutiae descriptors\\nYear: 2010\\n\\nAbstract: In forensic investigations, it is common for forensic investigators to obtain a photograph of evidence left at the scene of crimes to aid them catch the culprit(s). Although, fingerprints are the most popular evidence that can be used, scene of crime officers claim that more than 30% of the evidence recovered from crime scenes originate from palms. Usually, palmprints evidence left at crime scenes are partial since very rarely full palmprints are obtained. In particular, partial palmprints do not exhibit a structured shape and often do not contain a reference point that can be used for their alignment to achieve efficient matching. This makes conventional matching methods based on alignment andminutiae pairing, as used in fingerprint recognition, to fail in partial palmprint recognition problems. In this paper a new partial-to-full palmprint recognition based on invariant minutiae descriptors is proposedwhere the partial palmprint's minutiae are extracted and considered as the distinctive and discriminating features for each palmprint image. This is achieved by assigning to eachminutiae a feature descriptor formed using the values of all the orientation histograms of the minutiae at hand. This allows for the descriptors to be rotation invariant and as such do not require any image alignment at the matching stage. The results obtained showthat the proposed technique yields a recognition rate of 99.2%. The solution does give a high confidence to the judicial jury in their deliberations and decision.\",\n \"Title: Reversible watermarking using statistical information\\nYear: 2010\\n\\nAbstract: In most reversible watermarking methods, a compressed locationmap is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.\",\n \"Title: A novel prostate cancer classification technique using intermediate memory tabu search\\nYear: 2005\\n\\nAbstract: The introduction of multispectral imaging in pathology problems such as the identification of prostatic cancer is recent. Unlike conventional RGB color space, it allows the acquisition of a large number of spectral bands within the visible spectrum. This results in a feature vector of size greater than 100. For such a high dimensionality, pattern recognition techniques suffer from the well-known curse of dimensionality problem. The two well-known techniques to solve this problem are feature extraction and feature selection. In this paper, a novel feature selection technique using tabu search with an intermediate-term memory is proposed. The cost of a feature subset is measured by leave-one-out correct-classification rate of a nearest-neighbor (1-NN) classifier. The experiments have been carried out on the prostate cancer textured multispectral images and the results have been compared with a reported classical feature extraction technique. The results have indicated a significant boost in the performance both in terms of minimizing features and maximizing classification accuracy.\",\n \"Title: An FPGA Based Coprocessor for the Classification of Tissue Patterns in Prostatic Cancer\\nYear: 2004\\n\\nAbstract: This paper discusses the suitability of reconfigurable, computing to speedup medical image classification problems. As an example of the speedup offered by reconfigurable logic, a multispectral computer vision system for automatic diagnosis of prostatic cancer is implemented. Different parallel architectures for various steps in automatic diagnosis are proposed and implemented in Field Programmable Gate Arrays (FPGAs). The first step of the algorithm is to compute Grey Level Co-occurrence Matrix (GLCM). The second step involves the normalisation of GLCM. The third step of the algorithm is to compute texture features from the normalised GLCM. The last step is concerned with image classification using linear discriminant analysis (LDA). Finally, the performance of the proposed system is assessed and compared against a microprocessor based solution. The results obtained clearly show that the proposed solution compares favorably.\",\n \"Title: Adaptive binary mask for privacy region protection\\nYear: 2012\\n\\nAbstract: Privacy region protection in video surveillance systems is an active topic at present. In previous research, a binary mask mechanism has been developed to indicate the privacy region; however this incurs a significant bitrate overhead. In this paper, an adaptive binary mask is proposed to represent the privacy region. In a practical privacy region protection application, in which the privacy region typically occupies less than half of the overall frame and is rectangular or approximately rectangular, the proposed adaptive binary mask can effectively reduce the bitrate overhead. The proposed method can also be easily applied to the FMO mechanism of H.264/AVC, providing both error resilience and a lower bitrate overhead.\",\n \"Title: Spread Transform Watermarking for Digital Multimedia Using the Complex Wavelet Domain\\nYear: 2007\\n\\nAbstract: Complex wavelets offer several improvements over their discretely sampled counterparts such as improved directionality and shift invariance allowing for better representation of image features. This has important implications for watermark embedding and modelling of the human visual system that is important to satisfy the imperceptibility requirement of watermarking systems. In addition spread transform watermarking has emerged as a method of combining the advantages of spread spectrum and quantization based data hiding algorithms, offering improved levels of capacity and robustness. This paper applies spread transform embedding and the complex wavelet domain to the case of grey scale, colour image and video watermarking.\",\n \"Title: A new methodology in steganalysis: breaking highly undetectable steganograpy (HUGO)\\nYear: 2011\\n\\nAbstract: This paper presents a new methodology for the steganalysis of digital images. In principle, the proposed method is applicable to any kind of steganography at any domain. Special interest is put on the steganalysis of Highly Undetectable Steganography (HUGO). The proposed method first extracts features via applying a function to the image, constructing the k variate probability density function (PDF) estimates, and downsampling it by a suitable downsampling algorithm. The extracted feature vectors are then further optimized in order to increase the detection performance and reduce the computational time. Finally using a supervised classification algorithm such as SVM, steganalysis is performed. The proposed method is capable of detecting BOSSRank image set with an accuracy of 85%.\",\n \"Title: Image segmentation by relaxation using constraint satisfaction neural network\\nYear: 2002\\n\\nAbstract: The problem of image segmentation using constraint satisfaction neural networks (CSNN) has been considered. Several variations of the CSNN theme have been advanced to improve its performance or to explore new structures. These new segmentation algorithms are based on interplay of additional constraints, of varying the organization of the network or modifying the relaxation scheme. The proposed schemes are tested comparatively on a bank of test images as well as real world images.\",\n \"Title: SVD-Based Universal Spatial Domain Image Steganalysis\\nYear: 2010\\n\\nAbstract: This paper is concerned with the universal (blind) image steganalysis problem and introduces a novel method to detect especially spatial domain steganographic methods. The proposed steganalyzer models linear dependencies of image rows/columns in local neighborhoods using singular value decomposition transform and employs content independency provided by a Wiener filtering process. Experimental results show that the novel method has superior performance when compared with its counterparts in terms of spatial domain steganography. Experiments also demonstrate the reasonable ability of the method to detect discrete cosine transform-based steganography as well as the perturbation quantization method.\",\n \"Title: Palmprint Recognition Based on Subspace Analysis of Gabor Filter Bank\\nYear: 2010\\n\\nAbstract: This paper introduces a new technique for palmprint recognition based on Fisher Linear Discriminant Analysis (FLDA) of Gabor filter bank. This method involves convolving a palmprint image with a bank of Gabor filters at different scales and rotations for robust palmprint features extraction. Once these feature are extracted, FLDA is applied for dimensionality reduction and class separability. Since the palmprint features are derived from the principal lines, wrinkles and texture along the palm area one should carefully consider this fact when selecting the appropriate palm region for feature extraction process in order to enhance recognition accuracy. To address this problem, an improved region of interest (ROI) extraction algorithm is introduced. This algorithm allows for an efficient extraction of the whole palm area ignoring all the undesirable parts, such as the fingers and background. Experiments have shown that the proposed method yields attractive performances evidence by an Equal Error Rate (EER) of 0.03%.\",\n \"Title: Palmprint Recognition Based On Subspace Analysis Of Gabor Filter Bank\\nYear: 2009\\n\\nAbstract: This paper introduces a new technique for palmprint recognition based on Fisher Linear Discriminant Analysis (FLDA) and Gabor filter bank. This method involves convolving a palmprint image with a bank of Gabor filters at different scales and rotations for robust palmprint features extraction. Once these features are extracted, FLDA is applied for dimensionality reduction and class separability. Since the palmprint features are derived from the principal lines, wrinkles and texture along the palm area. One should carefully consider this fact when selecting the appropriate palm region for the feature extraction process in order to enhance recognition accuracy. To address this problem, an improved region of interest (ROI) extraction algorithm is introduced. This algorithm allows for an efficient extraction of the whole palm area by ignoring all the undesirable parts, such as the fingers and background. Experiments have shown that the proposed method yields attractive performances as evidenced by an Equal Error Rate (EER) of 0.03%.\",\n \"Title: SVD based image manipulation detection\\nYear: 2010\\n\\nAbstract: In this paper we present a novel method based on singular value decomposition (SVD) for forensic analysis of digital images. We show that image tampering distorts linear dependencies of image rows/columns and derived features can be accurate enough to detect image manipulations and digital forgeries. Extensive experiments show that the proposed approach can outperform the counterparts in the literature.\",\n \"Title: The improved sign bit encryption of motion vectors for H.264/AVC.\\nYear: 2012\\n\\nAbstract: In this paper, an improved video encryption method for encrypting the sign bit of motion vectors is proposed based on H.264/AVC, which belongs to selective encryption. This method improves upon previous work involving the sign bit encryption of motion vectors by ensuring the four candidates for the encrypted motion vectors are always located in two orthogonal lines. The improved method can provide a much more effective scrambling effect while keeping the encrypted stream format-compliant and the compression ratio unchanged. The combination of the proposed method with encryption of intra prediction modes can further enhance the scrambling effect, especially for the first few frames which are left clear when only the motion vectors are encrypted.\",\n \"Title: Robust Motion Detection via the Fuzzy Fusion of 6D Feature Space Decompositions\\nYear: 2009\\n\\nAbstract: A change detection framework which fuses both spatial and temporal data using fuzzy if-then rules is presented. Temporal data is used on a per-pixel basis to monitor the sequence for changes by employing a fuzzy codebook model. Spatial data is gathered using a fuzzy multithresholding algorithm that decomposes the RGB color space into three color pair histograms. This system is found to be robust to noise and allows the algorithm to process successfully even when the underlying sequences result in under-segmentation of the spatial data.\",\n \"Title: A Tunable Encryption Scheme and Analysis of Fast Selective Encryption for CAVLC and CABAC in H.264/AVC\\nYear: 2013\\n\\nAbstract: Recently, two fast selective encryption methods for context-adaptive variable length coding and context-adaptive binary arithmetic coding in H.264/AVC were proposed by Shahid et. al. In this paper, it was demonstrated that these two methods are not as efficient as only encrypting the sign bits of nonzero coefficients. Experimental results showed that without encrypting the sign bits of nonzero coefficients, these two methods can not provide a perceptual scrambling effect. If a much stronger scrambling effect is required, intra prediction modes, and the sign bits of motion vectors can be encrypted together with the sign bits of nonzero coefficients. For practical applications, the required encryption scheme should be customized according to a user's specified requirement on the perceptual scrambling effect and the computational cost. Thus, a tunable encryption scheme combining these three methods is proposed for H.264/AVC. To simplify its implementation and reduce the computational cost, a simple control mechanism is proposed to adjust the control factors. Experimental results show that this scheme can provide different scrambling levels by adjusting three control factors with no or very little impact on the compression performance. The proposed scheme can run in real-time and its computational cost is minimal. The security of the proposed scheme is also discussed. It is secure against the replacement attack when all three control factors are set to one.\",\n \"Title: JPEG Image Steganalysis Using Multivariate PDF Estimates With MRF Cliques\\nYear: 2013\\n\\nAbstract: Blind steganalysis of JPEG images is addressed by modeling the correlations among the DCT coefficients using $K$ -variate $(K\\\\\\\\geq 2)$ p.d.f. estimates (p.d.f.s) constructed by means of Markov random field (MRF) cliques. The reasoning of using high variate p.d.f.s together with MRF cliques for image steganalysis is explained via a classical detection problem. Although our approach has many improvements over the current state-of-the-art, it suffers from the high dimensionality and the sparseness of the high variate p.d.f.s. The dimensionality problem as well as the sparseness problem are solved heuristically by means of dimensionality reduction and feature selection algorithms. The detection accuracy of the proposed method(s) is evaluated over Memon's (30.000 images) and Goljan's (1912 images) image sets. It is shown that practically applicable steganalysis systems are possible with a suitable dimensionality reduction technique and these systems can provide, in general, improved detection accuracy over the current state-of-the-art. Experimental results also justify this assertion.\",\n \"Title: New FMO type to flag ROI in H.264/AVC\\nYear: 2014\\n\\nAbstract: This paper presents a new type of Flexible Macroblock Ordering (FMO) type for the H.264 Advanced Video Coding (AVC) standard, which can more efficiently flag the position and shape of regions of interest (ROIs) in each frame. In H.264/AVC, 7 types of FMO have been defined, all of which are designed for error resilience. Most previous work related to ROI processing has adopted Type-2 (foreground & background), or Type-6 (explicit), to flag the position and shape of the ROI. However, only rectangular shapes are allowed in Type-2 and for non-rectangular shapes, the non-ROI macroblocks may be wrongly flagged as being within the ROI, which could seriously affect subsequent processing of the ROI. In Type-6, each macroblock in a frame uses fixed-length bits to indicate to its slice group. In general, each ROI is assigned to one slice group identity. Although this FMO type can more accurately flag the position and shape of the ROI, it incurs a significant bitrate overhead. The proposed new FMO type uses the smallest rectangle that covers the ROI to indicate its position and a spiral binary mask is employed within the rectangle to indicate the shape of the ROI. This technique can accurately flag the ROI and provide significantly savings in the bitrate overhead. Compared with Type-6, an 80% to 90% reduction in the bitrate overhead can be obtained while achieving the same accuracy.\",\n \"Title: Colour image watermarking in the complex wavelet domain.\\nYear: 2003\\n\\nAbstract: Digital image watermarking has become a very active research area. One key requirement in designing a watermarking system is that there should be no perceptible difference between the watermarked and original image, and the watermark should be difficult to remove or alter without damaging the host image. However, these two somewhat different requirements are usually closely related. This paper is concerned with an investigation of different methods to increase imperceptibility and robustness of colour watermarks embedded in colour host images using the Complex Wavelet Transform (CWT). The Complex Wavelet Transform was chosen because experimentation results from have shown the CWT to be more robust than other transforms under compression, additive noise, median and mean filtering attacks. Fusion based watermarking has been chosen since it provides a visual authentication of the watermark.\",\n \"Title: An FPGA based co-processor for GLCM texture features measurement\\nYear: 2003\\n\\nAbstract: Gray Level Co-occurrence Matrix (GLCM), one of the best known texture analysis methods, estimates image properties related to second-order statistics. These image properties commonly known as texture features can be used for image classification, image segmentation, and remote sensing applications. In this paper, we present an FPGA based co-processor to accelerate the extraction of texture features from GLCM. Handel-C, a recently developed C-like programming language for hardware design, has been used for the FPGA implementation of GLCM texture features measurement. Results show that the FPGA has better speed performances when compared to a general purpose processor for the extraction of GLCM features.\",\n \"Title: Unsupervised histogram based color image segmentation.\\nYear: 2003\\n\\nAbstract: In this paper, a new technique is proposed for the segmentation of color images. The technique is based on the use of the sigma filter and multithresholding of 2-band histograms. A sigma filter is first applied to smooth out regions while keeping edges. Histograms are then computed, smoothed and downsampled. A peak picking algorithm finds the predominant peaks in the histograms. A concordance process between the dominant peaks is performed to determine the corresponding peaks in the histograms. Labels are assigned to corresponding peaks. The resulting histograms are partitioned into regions having the right labels. The partitioned histograms are used to segment the R, G and B bands. Finally, the segmented bands are fused together to give the final segmented image.\",\n \"Title: Comparison of different wavelet transforms for fusion based watermarking applications.\\nYear: 2003\\n\\nAbstract: In this paper, we have investigated and assessed different wavelet transforms for use in fusion based watermarking applications. Scalar (discrete) wavelet, multiwavelet, complex wavelet and wavelet packet transforms have been studied to answer the following question: Which transform provides a better watermarking robustness given a certain imperceptibility factor? Fusion based watermarking has been chosen since it provides a visual authentication of the watermark. Perceptual embedding has been omitted to provide a fair comparison since different transforms have yielded different locations for the embedding process. It has been found that the CWT outperforms the other transforms while the WPT gives the worst results.\",\n \"Title: A frontal view gait recognition based on 3D imaging using a time of flight camera\\nYear: 2014\\n\\nAbstract: Studies have been carried out to recognize individuals from a frontal view using their gait patterns. In previous work, gait sequences were captured using either single or stereo RGB camera systems or the Kinect 1.0 camera system. In this research, we used a new frontal view gait recognition method using a laser based Time of Flight (ToF) camera. In addition to the new gait data set, other contributions include enhancement of the silhouette segmentation, gait cycle estimation and gait image representations. We propose four new gait image representations namely Gait Depth Energy Image (GDE), Partial GDE (PGDE), Discrete Cosine Transform GDE (DGDE) and Partial DGDE (PDGDE). The experimental results show that all the proposed gait image representations produce better accuracy than the previous methods. In addition, we have also developed Fusion GDEs (FGDEs) which achieve better overall accuracy and outperform the previous methods.\",\n \"Title: Data cleaning and outlier removal: Application in human skin detection\\nYear: 2014\\n\\nAbstract: An outlier removal based data cleaning technique is proposed to clean manually pre-segmented human skin data in colour images. The 3-dimensional colour data is projected onto three 2-dimensional planes, from which outliers are removed. The cleaned 2 dimensional data projections are merged to yield a 3D clean RGB data. This data is finally used to build a look up table and a single Gaussian classifier for the purpose of human skin detection in colour images.\",\n \"Title: Detecting packed executables using steganalysis\\nYear: 2014\\n\\nAbstract: This paper proposes a novel method of detecting packed executable files using steganalysis, primarily targeting the detection of obfuscated malware through packing. Considering that over 80% of malware in the wild is packed, detection accuracy and low false negative rates are important properties of malware detection methods. Experimental results outlined in this paper reveal that the proposed approach achieving an overall detection accuracy of greater than 99%, a false negative rate of 1% and a false positive rate of 0%.\",\n \"Title: An improved wavelet-based image watermarking technique\\nYear: 2005\\n\\nAbstract: This paper proposes an adaptive blind image watermarking technique based on wavelet transform using a random sequence of real numbers. First, the image is decomposed into non overlapping blocks. Then, each block is classified as uniform or non uniform by using a JND-based classifier. The strength of the embedded watermark into the high subband coefficients of each transformed block depends upon the nature of the block according to its classification. The Neyman-Pearson criterion is used to derive the detection rule. Unlike the embedding process, the detection does not require any classification of blocs. This adaptive approach has been assessed on various standard images and compared with a similar watermarking technique (H. Inoue et al., 1999). The results have shown an obvious improvement in terms of robustness against different manipulations and a better ability of detection\",\n \"Title: On the Optimum Multiplicative Watermark Detection in the Transform Domain\\nYear: 2006\\n\\nAbstract: ABSTRACT This paper presents an investigation on the optimum,detection of multiplicative watermarks,based on statistical behaviour of image contents in the transform domain. In recent works, the problem of watermark,detection is viewed,as a binary decision where the ob- servation is the possibly watermarked,transformed coefficients. In- deed, the detector verifies whether the watermark presented to its in- put is actually embedded,in the input image (hypothesis H1) or not (hypothesis H0). Such a detection scheme,relies on the Neyman- Pearson criterion to derive a decision threshold by minimising,the probability of missed detection with respect to a given probability of false alarm. Previous works approximate,the probability density function (pdf) of the observation when hypothesis H0 holds by the pdf when,hypothesis of having no watermark,embedded,in the input image is in force by assuming,that the watermark,strength is weak to some extent. However, the weakness of the watermark does fulfil the requirement on the robustness. Moreover, from the viewpoint of the decision theory, the smaller the embedding depth, the worse the watermark,detection. This paper describes the drawback,behind this approximation,in the general case and proposes an efficient so- lution closer to the theoretical derivation. To validate the proposed technique, we consider a special case in which the Laplace statistical model is used. Index Terms— Image watermarking, multiplicative watermark,\",\n \"Title: A Robust Blind Image Watermarking Scheme in the SPIHT-Compressed Bit-Stream\\nYear: 2006\\n\\nAbstract: Practical digital multimedia is usually encountered in compressed format, and as such it is highly desirable to develop watermarking algorithms that operate totally in the compressed domain. In addition, watermarking schemes working jointly with SNR-scalable compression algorithms would be of great interest since the watermarks could be entirely retrieved at a given bit-rate. In this context, this paper proposes a robust blind image watermarking scheme operating in the SPIHT-compressed bit-stream. First, the watermark, which is a binary sequence, is encoded with an error-correction coding and interleaved to minimize the error decoding probability and combat bursts of errors. Then, in the course of SPIHT encoding process, the list of significant pixels (LSP) is used to embed the watermark sequence in a uniform quantisation manner at a given threshold where the coefficients of interest are differently refined in the next passes. Experimental results, carried out on various images, have shown the robustness of the watermark in the presence of different attacks.\",\n \"Title: Robust motion detection by fusion of 6D feature space decompositions\\nYear: 2008\\n\\nAbstract: ABSTRACT Amotion,detection framework ,is presented ,that integrates spatial and temporal data by decomposition, of ,the feature space. Temporal data is employed to monitor frame changes on a per-pixel basis, whilst the spatial data is used to provide region-based segmentation of image frames. The thresholded difference image from the change detection is then ,fused with the segmented ,image. It is found that this framework greatly improves robustness to noise, while retaining and, in some cases, improving the sensitivity to regions of interest. Further, the decomposition reduces the time required to run due to the reduction in computationalcomplexity. Index Terms— Image motion analysis, Image segmentation 1. INTRODUCTION CCTV cameras ,have found their way ,into almost every public space outside the home ,in the ,UK. Due to this ubiquity the sheer volume ,of data ,gathered has become unwieldy,from a manual ,analysis viewpoint. A potential cost-effective solution to this ,problem ,is the ,use of automated analysis software. The,first step in such systems isthat of motion ,or foreground ,detection. There has been much work done in this area, and there is a growing acceptance,within the community ,that this is a ,solved\",\n \"Title: Paralysis: An Extensible Multi-tiered Guidance Environment for Program Parallelization and Analysis\\nYear: 2013\\n\\nAbstract: The heterogeneous computing revolution continues unabated. Yet despite the vast number of naïve users in possession of bespoke software hoping to embrace the opportunities that this revolution has wrought, few approaches proposed in current literature can guide such users in these efforts. The most appropriate choice would appear to be a (semi-)automating compiler. However, these typically target a single device-type and demand the unguided use of directives. Consequently, they are of little use when naïve users are seeking answers to more fundamental questions, such as: which fragments of a program can/should be parallelized, which device should each fragment target, and what speedup will be attained. To this end, this paper expands on previous work and proposes Paralysis - an extensible guidance environment, tiered for varying programmer competencies with support for static and dynamic analysis techniques. At the highest level, guided user experiences are paramount. At the lowest level, underlying functionality is exposed as a set of plug-ins, ensuring longevity. A partial prototype, built atop the Cetus infrastructure, is described. It is used to analyze two serial programs for CUDA execution - the DFT and the Box Blur Filter. Speedups of 15x and 22x are achieved on the basis of the analysis.\",\n \"Title: Video steganalysis of LSB based motion vector steganography\\nYear: 2013\\n\\nAbstract: This paper proposes a novel flatness measure for video steganalysis targeting LSB based motion vector steganography. The proposed method has introduced two major improvements. Firstly, unlike previous approaches, it takes into account the anchor frame and current frame distances and directions, which significantly affect the correlation strength of adjacent motion vectors. Secondly, it defines a cover model that does not require a training based machine learning system. Large amounts of videos including broad range of motion patterns have been used in order to approximate the real detection rate of the proposed method. Test results show that proposed algorithm successfully classifies cover and stego videos.\",\n \"Title: Perceptual watermarking for Discrete Shearlet transform\\nYear: 2014\\n\\nAbstract: This paper presents a new perceptual watermarking model for Discrete Shearlet transform (DST). DST provides the optimal representation [10] of the image features based on multi-resolution and multi-directional analysis. This property can be exploited on for watermark embedding to achieve the watermarking imperceptibility by introducing the human visual system using Chou's model. In this model, a spatial JND profile is adapted to fit the sub-band structure. The combination of DST and the Just-Noticeable Distortion (JND) profile improves the levels of robustness against certain attacks while minimizing the distortion; by assigning a visibility threshold of distortion to each DST sub-band coefficient in the case of grey scale image watermarking.\",\n \"Title: A scalable SPIHT-based multispectral image compression technique\\nYear: 2006\\n\\nAbstract: This paper addresses the compression of multispectral im- ages which can be viewed, at the encoder side, as a three- dimensional (3D) data set characterized by a high correlation through the successive bands. Recently, the celebrated 3D- SPIHT (Sets Partitioning In Hierarchical Trees) algorithm has been widely adopted in the literature for the coding of mul- tispectral images because of its proven state-of-the art per- formance. In order to exploit the spectral redundancy in the 3D wavelet transform domain, a new scalable SPIHT based multispectral image compression technique is proposed. The rational behind this approach is that image components in two consecutive transformed bands are significantly dependent in terms of zerotrees locations in the 3D-DWT domain. There- fore, by joining the trees with the same location into the List of Insignificant Sets (LIS), a considerable amount of bits can be reduced in the sorting pass in comparison with the separate encoding of the transformed bands. Numerical experiments on two sample multispectral images show a highly better per- formance of the proposed technique when compared to the conventional 3D-SPIHT. Currently, with the huge advance in the use and distribu- tion of digital multimedia data, the transmission and delivery of massively large images over heterogeneous data networks has turned out to be a real preoccupation for an increasing number of researchers in the field of image compression. Sat- isfying the requests in terms of image quality under the con- straint of the diversity of the traffic on the network is a real issue. Since the server must satisfy the users having both high and low bandwidth simultaneously, a straightforward solution to the problem is to compress and store the encoded version of the image data at different bit-rates. However, this approach involves providing the server with a large disk space and a management system for the stored data. Therefore, scalabil- ity, the capability of decoding a compressed image at different bit-rates, provides an attractive solution, allowing only one encoded image version to be stored in the database thereby avoiding the overhead of maintaining several versions of the coded data at various bit rates. In rate scalable coding, all of the compressed data is embedded in a single bit stream which can be decoded at different bit-rates. The decompression al- gorithm receives and decodes the compressed data from the start of the bit stream until a desired data rate is achieved.\",\n \"Title: Spread transform video watermarking using 3D complex wavelets\\nYear: 2007\\n\\nAbstract: A novel video watermarking system is presented that uses a spread transform technique to securely embed data into a video sequence, resistant to both spatial and temporal attacks. The system makes use of the 3-D wavelet domain, improving embedding by extending this to include complex as well as discretely sampled wavelet transforms. To ensure imperceptibility an adaptation of a proven video visual model is used. Results are given for both compression and frame dropping attacks.\",\n \"Title: Colour spread transform data hiding capacity using complex wavelets\\nYear: 2007\\n\\nAbstract: Information theoretic methods of calculating the capacity of data hiding schemes allow for objective comparisons of watermarking algorithms. This paper applies these methods to the case of colour image watermarking, using a dual tree complex wavelet transform and non redundant complex wavelet transform along with a spread transform data hiding algorithm to compare levels of capacity between the two most commonly used uncorrelated colour spaces. The information theoretic model used involves the use of game theory applied to optimize the embedding and attack strategy across parallel Gaussian channels. The two most popular uncorrelated colour spaces YUV and YIQ are compared.\",\n \"Title: A novel modality independent score-level quality measure\\nYear: 2010\\n\\nAbstract: The performance of biometric systems deployed in real world scenarios is affected adversely by the degradation in the input quality. This degradation can take place either in the input or due to inherent design of the deployed system. Quality Measures aim to provide a quantitative indication of this degradation which can be utilized to help access the probability that the provided biometric decision is correct. In this paper we present a novel, modality independent, score level quality measure based on Mahalanobis Distance. This measure exploits the inter-dependencies which exist between the data and matching score to reduce the error rates and improve the performance of the deployed biometric system. The effectiveness of the proposed approach is verified by extensive testing using the standard databases available of fingerprints and Iris data.\",\n \"Title: Privacy region protection for H.264/AVC with enhanced scrambling effect and a low bitrate overhead.\\nYear: 2015\\n\\nAbstract: While video surveillance systems have become ubiquitous in our daily lives, they have introduced concerns over privacy invasion. Recent research to address these privacy issues includes a focus on privacy region protection, whereby existing video scrambling techniques are applied to specific regions of interest (ROI) in a video while the background is left unchanged. Most previous work in this area has only focussed on encrypting the sign bits of nonzero coefficients in the privacy region, which produces a relatively weak scrambling effect. In this paper, to enhance the scrambling effect for privacy protection, it is proposed to encrypt the intra prediction modes (IPM) in addition to the sign bits of nonzero coefficients (SNC) within the privacy region. A major issue with utilising encryption of IPM is that drift error is introduced outside the region of interest. Therefore, a re-encoding method, which is integrated with the encryption of IPM, is also proposed to remove drift error. Compared with a previous technique that uses encryption of IPM, the proposed re-encoding method offers savings in the bitrate overhead while completely removing the drift error. Experimental results and analysis based on H.264/AVC were carried out to verify the effectiveness of the proposed methods. In addition, a spiral binary mask mechanism is proposed that can reduce the bitrate overhead incurred by flagging the position of the privacy region. A definition of the syntax structure for the spiral binary mask is given. As a result of the proposed techniques, the privacy regions in a video sequence can be effectively protected by the enhanced scrambling effect with no drift error and a lower bitrate overhead.\",\n \"Title: AN FPGA BASED PARAMETRISABLE SYSTEM FOR DISCRETE ORTHOGONAL TRANSFORMS IMPLEMENTATION\\nYear: 2002\\n\\nAbstract: This paper presents novel architectures for efficient implementation of Discrete Orthogonal Transforms (DOTs) using an FPGA based parameterisable system. These transforms are important in many signal and image processing applications including image and speech compression, filtering and coding. Two novel architectures for DOTs using both systolic architecture and distributed arithmetic design methodologies are presented. The first approach uses the Modified Booth-encoder-Wallace trees Multiplication (MBWM) algorithm for a systolic architecture implementation. The second approach is based on both distributed arithmetic ROM and accumulator structure, and Offset Binary Coding technique (OBC). Implementations of the algorithms on a Xilinx FPGA board are described. Distributed arithmetic approach exhibits better performances when compared with the systolic architecture approach.\",\n \"Title: Spatio-Temporal Rich Model For Motion Vector Steganalysis\\nYear: 2015\\n\\nAbstract: We propose a spatio-temporal rich model of motion vector planes as a part of a full steganalytic system against motion vector based steganography. Superior detection accuracy of the rich model over the previous methods has been lately demonstrated for digital images in both spatial and DCT domain. It has not been heretofore used for detection of motion vector steganography. We also introduced a transformation so as to extend the feature set with temporal residuals. We carried out the tests along with most recent motion vector steganalysis and steganography methods. Test results show that the proposed model delivers an outstanding performance compared to the previous methods.\",\n \"Title: Spatio-Temporal Rich Model-Based Video Steganalysis on Cross Sections of Motion Vector Planes.\\nYear: 2016\\n\\nAbstract: A rich model-based motion vector (MV) steganalysis benefiting from both temporal and spatial correlations of MVs is proposed in this paper. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this paper. First, it is shown that there i...\",\n \"Title: Video authentication based on statistical local information.\\nYear: 2016\\n\\nAbstract: With the outgrowth of video editing tools, video information trustworthiness becomes a hypersensitive field. Today many devices have the capability of capturing digital videos such as CCTV, digital cameras and mobile phones and these videos may transmitted over the Internet or any other non secure channel. As digital video can be used to as supporting evidence, it has to be protected against manipulation or tampering. As most video authentication techniques are based on watermarking and digital signatures, these techniques are effectively used in copyright purposes but difficult to implement in other cases such as video surveillance or in videos captured by consumer's cameras. In this paper we propose an intelligent technique for video authentication which uses the video local information which makes it useful for real world applications. The proposed algorithm relies on the video's statistical local information which was applied on a dataset of videos captured by a range of consumer video cameras. The results show that the proposed algorithm has potential to be a reliable intelligent technique in digital video authentication without the need to use for SVM classifier which makes it faster and less computationally expensive in comparing with other intelligent techniques.\",\n \"Title: Frontal View Gait Recognition With Fusion of Depth Features From a Time of Flight Camera.\\nYear: 2019\\n\\nAbstract: Frontal view gait recognition for people identification has been carried out using single RGB, stereo RGB, Kinect 1.0, and Doppler radar. However, existing methods based on these camera technologies suffer from several problems. Therefore, we propose a four-part method for frontal view gait recognition based on the fusion of multiple features acquired from a Time-of-Flight (ToF) camera. We have de...\",\n \"Title: Man-In-The-Middle Attacks in Vehicular Ad-Hoc Networks: Evaluating the Impact of Attackers' Strategies.\\nYear: 2018\\n\\nAbstract: Vehicular Ad-Hoc Network (VANET), a vital component of Intelligent Transportation Systems (ITS) technology, relies on communication between dynamically connected vehicles and static Road Side Units (RSU) to offer various applications (e.g., collision avoidance alerts, steep-curve warnings and infotainment). VANET has a massive potential to improve traffic efficiency, and road safety by exchanging critical information between nodes (vehicles and RSU), thus reducing the likelihood of traffic accidents. However, this communication between nodes is subject to a variety of attacks, such as Man-In-The-Middle (MITM) attacks which represent a major risk in VANET. It happens when a malicious node intercepts or tampers with messages exchanged between legitimate nodes. In this paper, we studied the impact on network performance of different strategies which attackers can adopt to launch MITM attacks in VANET, such as fleet or random strategies. In particular, we focus on three goals of MITM attacks-message delayed, message dropped and message tampered. The simulation results indicate that these attacks have a severe influence on the legitimate nodes in VANET as the network experience high number of compromised messages, high end-to-end delays and preeminent packet losses.\",\n \"Title: Blind Image Watermark Detection Algorithm Based on Discrete Shearlet Transform Using Statistical Decision Theory.\\nYear: 2018\\n\\nAbstract: Blind watermarking targets the challenging recovery of the watermark when the host is not available during the detection stage. This paper proposes Discrete Shearlet Transform (DST) as a new embedding domain for blind image watermarking. Our novel DST blind watermark detection system uses a nonadditive scheme based on the statistical decision theory. It first computes the Probability Density Funct...\",\n \"Title: A Comparative Analysis of Trust Models for Safety Applications in IoT-enabled Vehicular Networks\\nYear: 2019\\n\\nAbstract: Vehicular Ad-hoc NETwork (VANET) is a vital transportation technology that facilitates the vehicles to share sensitive information (such as steep-curve warnings and black ice on the road) with each other and with the surrounding infrastructure in real-time to avoid accidents and enable comfortable driving experience.To achieve these goals, VANET requires a secure environment for authentic, reliable and trusted information dissemination among the network entities. However, VANET is prone to different attacks resulting in the dissemination of compromised/false information among network nodes. One way to manage a secure and trusted network is to introduce trust among the vehicular nodes. To this end, various Trust Models (TMs) are developed for VANET and can be broadly categorized into three classes, Entity-oriented Trust Models (ETM), Data oriented Trust Models (DTM) and Hybrid Trust Models (HTM). These TMs evaluate trust based on the received information (data), the vehicle (entity) or both through different mechanisms. In this paper, we present a comparative study of the three TMs. Furthermore, we evaluate these TMs against the different trust, security and quality-of-service related benchmarks. Simulation results revealed that all these TMs have deficiencies in terms of end-to-end delays, event detection probabilities and false positive rates. This study can be used as a guideline for researchers to design new efficient and effective TMs for VANET.\",\n \"Title: Realization of Blockchain in Named Data Networking-Based Internet-of-Vehicles\\nYear: 2019\\n\\nAbstract: The revolution of Internet-of-vehicles (IoV) has stimulated a substantial response from academia, research, and industry due to its massive potential to improve overall transportation. Current IoV faces huge challenges due to its reliance on IP-based network architecture. Therefore, named data networking (NDN) is proposed as a promising architecture to solve issues posed by IP-based systems. Recently, blockchains (BCs) have been utilized within IoV to increase network security. However, the integration of BC within NDN-enabled IoV is still an open research problem. In this study, we proposed a novel tier-based architecture known as “Blockchain in NDN-enabled Internet-of-vehicles (BINDN),” which can support BC within NDN-enabled IoV. BINDN can be used as reference architecture to design security solutions in NDN-enabled IoV using BC. Furthermore, it provides an extensive set of applications including IoV security, trust management, and privacy enhancements. Moreover, we highlighted major challenges and issues when integrating BC within NDN-enabled IoV.\",\n \"Title: A Survey of Deep Learning Solutions for Multimedia Visual Content Analysis.\\nYear: 2019\\n\\nAbstract: The increasing use of social media networks on handheld devices, especially smartphones with powerful built-in cameras, and the widespread availability of fast and high bandwidth broadband connections, added to the popularity of cloud storage, is enabling the generation and distribution of massive volumes of digital media, including images and videos. Such media is full of visual information and holds immense value in today's world. The volume of data involved calls for automated visual content analysis systems able to meet the demands of practice in terms of efficiency and effectiveness. Deep learning (DL) has recently emerged as a prominent technique for visual content analysis. It is data-driven in nature and provides automatic end-to-end learning solutions without the need to rely explicitly on predefined handcrafted feature extractors. Another appealing characteristic of DL solutions is the performance they can achieve, once the network is trained, under practical constraints. This paper identifies eight problem domains which require analysis of visual artifacts in multimedia. It surveys the recent, authoritative, and the best performing DL solutions and lists the datasets used in the development of these deep methods for the identified types of visual analysis problems. This paper also discusses the challenges that the DL solutions face which can compromise their reliability, robustness, and accuracy for visual content analysis.\",\n \"Title: A Novel Security Methodology For Smart Grids: A Case Study Of Microcomputer-Based Encryption For Pmu Devices\\nYear: 2021\\n\\nAbstract: Coordination of a power system with the phasor measurement devices (PMUs) in real time on the load and generation sides is carried out within the context of smart grid studies. Power systems equipped with information systems in a smart grid pace with external security threats. Developing a smart grid which can resist against cyber threats is considered indispensable for the uninterrupted operation. In this study, a two-way secure communication methodology underpinned by a chaos-based encryption algorithm for PMU devices is proposed. The proposed system uses the IEEE-14 busbar system on which the optimum PMU placement has been installed. The proposed hyperchaotic system-based encryption method is applied as a new security methodology among PMU devices. The success of results is evaluated by the completeness of data exchange, durations, the complexity of encryption-decryption processes, and strength of cryptography using a microcomputer-based implementation. The results show that the proposed microcomputer-based encryption algorithms can be directly embedded as encryption hardware units into PMU and PDC devices which have very fast signal processing capabilities taking into considerations the acceptable delay time for power system protection and measuring applications and quality metering applications which is 2 ms and 10 ms, respectively. While proposed algorithms can be used in TCP or UDP over IP-based IEEE C37.118, IEC 61850, and IEC 61850-90-5 communication frameworks, they can also be embedded into electronic cards, smartcards, or smart tokens which are utilized for authentication among smart grid components.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":62,"string":"62"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13354,"string":"13,354"}}},{"rowIdx":13355,"cells":{"question_id":{"kind":"string","value":"Miao Yu"},"question":{"kind":"string","value":"Generate an abstract for the title \"Research on Brake Thermal Simulation Technology Based on Heat Flux Theory\" using the following items: 1. Heat flux theory\n2. Thermal simulation\n3. Braking system\n4. Temperature change curve\n5. AMS operating conditions"},"answer":{"kind":"string","value":"Based on the heat flux theory, the thermal simulation mathematical model of the braking system is established. By inputting the braking system parameters and some vehicle parameters into the model, the thermal simulation calculation of the braking system based on AMS operating conditions can be performed, and the temperature change curve of the entire braking process can be obtained. Comparing the..."},"correct_answer":{"kind":"string","value":"Based on the heat flux theory, the thermal simulation mathematical model of the braking system is established. By inputting the braking system parameters and some vehicle parameters into the model, the thermal simulation calculation of the braking system based on AMS operating conditions can be performed, and the temperature change curve of the entire braking process can be obtained. Comparing the..."},"documents":{"kind":"list like","value":["Title: Design and Implementation of Common Map Symbol System in GIS\nYear: 2008\n\nAbstract: Map symbol has important effect in the process of GIS graphics. This paper introduce a GIS common symbol library, which is designed and implemented based on MapObjects' interface, include point symbol, line symbol and fill symbol and further illustration on how to save symbol in commercial database. At last, a case that using this symbol library is shown. This is a result tested in Zhejiang province in the Chinese numerical marine project and it achieves a good result.","Title: A posture recognition based fall detection system for monitoring an elderly person in a smart home environment.\nYear: 2012\n\nAbstract: We propose a novel computer vision based fall detection system for monitoring an elderly person in a home care application. Background subtraction is applied to extract the foreground human body and the result is improved by using certain post-processing. Information from ellipse fitting and a projection histogram along the axes of the ellipse are used as the features for distinguishing different postures of the human. These features are then fed into a directed acyclic graph support vector machine (DAGSVM) for posture classification, the result of which is then combined with derived floor information to detect a fall. From a dataset of 15 people, we show that our fall detection system can achieve a high fall detection rate (97.08%) and a very low false detection rate (0.8%) in a simulated home environment.","Title: Research on Coupling Characters of the Linear Polarized Mode between Two Multi-mode Silica Circular Waveguide.\nYear: 2011\n\nAbstract: Based on fiber coupling equation, this paper discusses the character of linear polarized mode coupling between two multi-mode silica circular waveguides which have the same dopant distribution. The Eigen values of linear polarized mode U, W are calculated based on the Eigen value equations. According to the numerical calculation, coupling coefficient and coupling length in different coupling angles are given, and the method to improve the efficiency of multimode fiber coupling is summarized.","Title: VGRIS: virtualized GPU resource isolation and scheduling in cloud gaming\nYear: 2013\n\nAbstract: Fueled by the maturity of virtualization technology for Graphics Processing Unit (GPU), there is an increasing number of data centers dedicated to GPU-related computation tasks in cloud gaming. However, GPU resource sharing in these applications is usually poor. This stems from the fact that the typical cloud gaming service providers often allocate one GPU exclusively for one game. To achieve the efficiency of computational resource management, there is a demand for cloud computing to employ the multi-task scheduling technologies to improve the utilization of GPU.\n\nIn this paper, we propose VGRIS, a resource management framework for Virtualized GPU Resource Isolation and Scheduling in cloud gaming. By leveraging the mature GPU paravirtualization architecture, VGRIS resides in the host through library API interception, while the guest OS and the GPU computing applications remain unmodified. In the proposed framework, we implemented three scheduling algorithms in VGRIS for different objectives, i.e., Service Level Agreement (SLA)-aware scheduling, proportional-share scheduling, and hybrid scheduling that mixes the former two. By designing such a scheduling framework, it is possible to handle different kinds of GPU computation tasks for different purposes in cloud gaming. Our experimental results show that each scheduling algorithm can achieve its goals under various workloads.","Title: A study of the inverse dynamics of a hybrid polishing kinematical machine tool based on the flexible multi-body systems\nYear: 2007\n\nAbstract: This paper presents a novel five DOF hybrid polishing kinematical machine tool (ffPKMT) which is made up of \"3 axes parallel + 2 axes series\" in order to obtain more stable machining result in the elastic polishing on the free-form surfaces. The dynamic characteristics of the HPKMT is studied in detail by means of the theory of dynamics of flexible multi-body systems. In order to control the HPKMT effectively, its characteristic of the kinematics and dynamics need be known deeply. The analysis of the inverse of mechanism is the important part in the research of dynamics. Adopting the same experiment condition with simulation analysis, the inverse kinematical trace of the three sliders can be obtained. It is shown that the simulation result is almost the same as the measured result from the experiment.","Title: Acceleration of fast factorized back projection algorithm for bistatic SAR\nYear: 2013\n\nAbstract: In this paper, we present an accelerated fast factorized back-projection algorithm designed for bistatic SAR data. This method supports a precise bistatic SAR image reconstruction and can attain high execution efficiency. Key to this method is the optimized parallel implementation of the original algorithm that can be executed on GPU. We make effort to a parallelization of factorized back-projection by a reasonable parallel strategy so that it can be implemented by CUDA on GPU. Moreover, we also do some optimization for a further improvement, including memory optimization and phase compute optimization, and when it comes to the translational-invariant data, an extra slant range compute optimization have been done yet. The validity and advantage of proposed approach are verified by simulated X-band bistatic SAR data and experimental data.","Title: Blind Separation of DS-CDMA Signals with ICA Method.\nYear: 2011\n\nAbstract: The Estimation of pseudo noise sequence and information sequence is of great importance in the security of DS-CDMA system, which remains a hot research problem in reconnaissance and supervision of wireless communication. In DS-CDMA system, the pseudo noise sequences of different users are uncorrelated and the information sequences of different users are statistical independent, thus independent component analysis (ICA) could be introduced to separate the DS-CDMA signals with little prior knowledge. In multipath situations, the recovered pseudo noise sequence with ICA is overlapped. For DSCDMA signals which utilize m-sequence as pseudo noise sequence, the triple correlation function (TCF) is introduced to eliminate the influence of overlap in this paper, which increases the estimation correct ratio greatly. Under the non-cooperative conditions, it is very difficult for the interceptor to aim at the very beginning of the transmitted signal. Certain offsets between the interceptor and the transmitter deteriorate the blind separation method obviously. The relationship between none convergence and the offset is found out and explained from eigen value decomposition. The validity of the proposed method and theory analysis is proved well by the simulation results at last. © 2011 Academy Publisher.","Title: A scalable key management and clustering scheme for ad hoc networks\nYear: 2006\n\nAbstract: This paper describes a scalable key management and clustering scheme for secure group communications in ad hoc and sensor networks. The scalability problem is solved by partitioning the communicating devices into subgroups, with a leader in each subgroup, and further organizing the subgroups into hierarchies. Each level of the hierarchy is called a tier or layer. Key generation, distribution, and actual data transmissions follow the hierarchy. The Distributed, Efficient Clustering Approach (DECA) provides robust clustering to form subgroups, and analytical and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility. Comparing with most other schemes, our approach is extremely scalable and efficient, provides more security guarantees, and is selective, adaptive and robust.","Title: Selection Cooperation in Heterogeneous Cooperative Networks.\nYear: 2014\n\nAbstract: Selection cooperation is an attractive cooperative strategy for wireless networks due to its simplicity and efficiency. In this paper, we consider a heterogeneous cooperative network consisting of different kinds of nodes with low-cost radios where the activities of one kind of nodes are triggered by the other kinds of nodes. This is a common scenario for many networks, such as wireless sensor networks. By exploiting the transmission relationship between heterogeneous nodes, we propose a selection cooperation protocol where inducing nodes can cooperate with the following nodes after their own transmissions for improving the communication reliability of the latter nodes. Through performance analysis, we show an interesting feature that the diversity-multiplexing tradeoff of the proposed protocol does not rely on the best relay selection method and the protocol always achieves the full diversity gain. We further develop an energy-efficient best relay selection method based on power control where the power consumption is minimized without decreasing the full diversity order. Simulation results demonstrate the good performance of the protocol and the remarkable energy reduction of the proposed best relay selection method.","Title: Vis: virtualization enhanced live acquisition for native system\nYear: 2011\n\nAbstract: Focusing on obtaining in-memory evidence, current live acquisition efforts either fail to provide accurate native system physical memory acquisition at the given time point or require suspending the machine and altering the execution environment drastically. To address this issue, we propose Vis, a light-weight virtualization approach to provide accurate retrieving of physical memory content while preserving the execution of target system. Vis encapsulates the native system into a single virtual machine and then conducts accurate acquisition by manipulating nested page table in hypervisor. We present the design and implementation of Vis, prove its acquisition reliability and evaluate its performance in live acquisition scenarios.","Title: A recurrent neural network modeling for automotive magnetorheological fluid shock absorber\nYear: 2005\n\nAbstract: Automotive Magnetorheological (MR) fluid shock absorbers have been previously characterized by a series of nonlinear differential equations, which have some difficulties in developing control systems. This paper presents a recurrent neural network with 3 input neurons, 1 output neuron and 5 recurrent neurons in the hidden layer to simulate behavior of MR fluid shock absorbers to develop control algorithms for suspension systems. A recursive prediction error algorithm has been applied to train the recurrent neural network using test data from lab where the MR fluid shock absorbers were tested by the MTS electro-hydraulic servo vibrator system. Training of neural network model has been done by means of the recursive prediction error algorithm presented in this paper and data generated from test in laboratory. In comparison with experimental results of MR fluid shock absorbers, the neural network models are reasonably accurate to depict performances of MR fluid shock absorber over a wide range of operating conditions.","Title: An online one class support vector machine-based person-specific fall detection system for monitoring an elderly individual in a room environment.\nYear: 2013\n\nAbstract: In this paper, we propose a novel computer vision-based fall detection system for monitoring an elderly person in a home care, assistive living application. Initially, a single camera covering the full view of the room environment is used for the video recording of an elderly person's daily activities for a certain time period. The recorded video is then manually segmented into short video clips containing normal postures, which are used to compose the normal dataset. We use the codebook background subtraction technique to extract the human body silhouettes from the video clips in the normal dataset and information from ellipse fitting and shape description, together with position information, is used to provide features to describe the extracted posture silhouettes. The features are collected and an online one class support vector machine (OCSVM) method is applied to find the region in feature space to distinguish normal daily postures and abnormal postures such as falls. The resultant OCSVM model can also be updated by using the online scheme to adapt to new emerging normal postures and certain rules are added to reduce false alarm rate and thereby improve fall detection performance. From the comprehensive experimental evaluations on datasets for 12 people, we confirm that our proposed person-specific fall detection system can achieve excellent fall detection performance with 100% fall detection rate and only 3% false detection rate with the optimally tuned parameters. This work is a semiunsupervised fall detection system from a system perspective because although an unsupervised-type algorithm (OCSVM) is applied, human intervention is needed for segmenting and selecting of video clips containing normal postures. As such, our research represents a step toward a complete unsupervised fall detection system.","Title: Sensor Response and Sensor Network Development for Practical Combustors\nYear: 2007\n\nAbstract: Meeting environmentally benign clean energy demands with expected growing population in the near term requires the development of smarter combustors and power plants. The future power plants will need to be more efficient and emit near zero emissions. This will require a significantly improved realtime control and analysis system. A single sensor from a combustor or any component in a power plant unit provides inadequate information about the fate of various ongoing processes within the system. We envision that future advanced power plants will have a large number of sensors to provide comprehensive information about the fate of various ongoing processes in the combustion system. Incorporating a large number of sensors in a sensor network will allow one to obtain comprehensive information, which can then be processed to visually display the detailed behavior in real time and support advanced control systems that can formulate the plant behavior. In this paper, we provide systematic development of a single sensor response from a combustor to understand the sensor's response on location and operational parameters. The results reveal the need for multiple sensor arrays for detailed visualization, analysis, and process control. These results will be used as a guideline for determining the type and nature of high density sensor network around the combustor of a power plant. Different issues and algorithms about high-density sensor networks in advanced combustors are also discussed.","Title: Average filtered blind separation of DS-CDMA signals with ICA method\nYear: 2010\n\nAbstract: In DS-CDMA system, the pseudo random sequences are none correlation and the information sequences of different user's are independent, thus Independent Component Analysis (ICA) is appropriate for the blind separate the DS-CDMA signals with little prior knowledge. Original blind separation method of DS-CDMA signals with ICA utilized only one sample value in each chip. However, in common DS-CDMA communication systems, the sample rate is much faster than the chip rate, so there are many samples during a chip interval. A method of average filtered blind separation of DS-CDMA signals with ICA is proposed in this paper. When noise is stationary, the method proposed could increase the input SNR of ICA greatly. The validity of the method is proved by the simulation results at last.","Title: Sensor coverage in wireless ad hoc sensor networks\nYear: 2007\n\nAbstract: We present our solutions to the general sensor coverage problem in wireless ad hoc sensor networks, where the sensors are heterogeneous in terms of sensing, communication and motion capabilities. We propose an integrated framework to accommodate such heterogeneity, in which sensors are logically organised into different tiers. We then address, for each given set of heterogeneous sensors, how the coverage problem can be solved. We first present our Sensing Neighbour Acquiring Protocol (SNAP) which renders correct neighbour information necessary for coverage algorithms. Then we provide our insights on coverage and the necessary and sufficient conditions for the coverage degree determination in a target area. Such theoretical results lead to our general and efficient coverage determination algorithm. Further, we prove that by using SNAP, coverage implies network connectivity. Without assuming uniform sensing ranges, our protocol, algorithm and theoretical results are generally applicable in a wide range of sensor network applications.","Title: Moderate deviation principle for autoregressive processes\nYear: 2009\n\nAbstract: A moderate deviation principle for autoregressive processes is established. As statistical applications we provide the moderate deviation estimates of the least square and the Yule-Walker estimators of the parameter of an autoregressive process. The main assumption on the autoregressive process is the Gaussian integrability condition for the noise, which is weaker than the assumption of Logarithmic Sobolev Inequality in [H. Djellout, A. Guillin, L. Wu, Moderate deviations of empirical periodogram and nonlinear functionals of moving average processes, Ann. I. H. Poincare-PR 42 (2006) 393-416].","Title: Discrete-time adaptive learning control for parametric uncertainties with unknown periods\nYear: 2013\n\nAbstract: In this paper, we approach the problem of unknown periods for a class of discrete-time parametric nonlinear systems with nonlinearities which do not necessarily satisfy the sector-bounded condition. The unknown periods hide in the parametric uncertainties, which is difficult to estimate. By incorporating a logic-based switching mechanism, we estimate the period and bound of unknown parameter simultaneously under Lyapunov-based analysis. Rigorous proof is given to demonstrate that a finite number of switchings can guarantee the asymptotic regulation of the nonlinear system considered. The simulation result also shows the efficacy of the proposed switching periodic adaptive control method.","Title: Adaptive fuzzy neural network control for transient dynamics of magneto-rheological suspension with time-delay\nYear: 2006\n\nAbstract: Since Magneto-rheological (MR) suspension has nonlinearity and time-delay, the application of linear feedback strategy has been limited. This paper addresses the problem of control of MR suspension with time-delay when transient dynamics are presented. An adaptive Fuzzy-Neural Network Control (FNNC) scheme for the transient course is proposed using fuzzy logic control and artificial neural network methodologies. To attenuate the adverse effects of time-delay on control performance, a Time Delay Compensator (TDC) is established. Then, through a numerical example of a quarter car model and a real road test with a bump input, the comparison is made between passive suspension and semi-active suspension. The results show that the MR vehicle with FNNC strategy can depress the peak acceleration and shorten the setting time, and the effect of time-delay can be attenuated. The results of road test with the similarity of numerical study verify the feasibility of the control strategy.","Title: Detecting and visualizing cartilage thickness without a shape model\nYear: 2012\n\nAbstract: This paper proposes a cartilage thickness detection and visualization method that does not utilize a shape model. The proposed method consists of three parts: volume of interest (VOI) initialization, bone segmentation, and cartilage thickness visualization. For VOI initialization, a novel 3D U-shape cuboidal filter is proposed to detect individual bones such as the femur, tibia, and patella, and for bone segmentation, a hybrid level-set method is adopted. Finally, a surface normal based approach is presented for measuring and visualizing the cartilage thickness. The advantage of the proposed method compared to other methods is that it does not require a shape model or any training process. The results demonstrate that the proposed method can be used for inspecting cartilage damage and loss.","Title: A robust fall detection system for the elderly in a Smart Room\nYear: 2010\n\nAbstract: In this paper, we propose a novel and robust fall detection system by using a density method for modeling a fall event as a function of certain video feature.3-D head velocity and human shape information are extracted as feature and three types of density model, single Gaussian, mixture of Gaussians and Parzen window method, are constructed for modeling the density of fall with respect to the extracted video feature. Falls are then detected according to the corresponding obtained density model and the success of the method is confirmed on real video sequences.","Title: A distributed efficient clustering approach for ad hoc and sensor networks\nYear: 2005\n\nAbstract: This paper presents a Distributed, Efficient Clustering Approach (DECA) for ad hoc and sensor networks. DECA can provide robustness against moderate node mobility and at the same time render energy-efficiency. The identified clusterheads cover the whole network and each node in the network can determine its cluster and only one cluster. The algorithm terminates in deterministic time without iterations, and each node transmits only one message during the algorithm. We prove analytically the correctness and complexity of the algorithm, and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility.","Title: A Lightweight Selection Cooperation Protocol with Multiple Available Best Relays\nYear: 2013\n\nAbstract: Selection cooperation has shown to be a practical cooperative strategy for wireless networks. In order to obtain full diversity gain, conventional selection cooperation schemes must select the node with the maximum relay-destination channel as the best relay, which restricts the choice of relay selection for the system. To overcome this limitation, we propose a lightweight selection cooperation protocol without requiring the radio of nodes to perform combining reception. Through outage probability and diversity-multiplexing tradeoff (DMT) analysis, we reveal an interesting fact that choosing any node that successfully receives the message from the source and the feedback frame from the destination as the best relay, the protocol always achieves the full diversity order and the optimal DMT. This result establishes a framework for obtaining multiple optimization objectives in selection cooperation networks. As an illustrative example, we then develop two best relay selection methods for relay balance without sacrificing the full diversity order. Simulation results demonstrate the remarkable performance and balance effect of the proposed protocol and selection methods.","Title: Design and fabrication of flexible parylene-based inductors with electroplated NiFe magnetic core for wireless power transmission system\nYear: 2012\n\nAbstract: Integrated flexible parylene-based MEMS inductors were successfully designed, fabricated and analyzed. By elctrodeposition technique, Ni80Fe20 Permalloy with high permeability was acquired as the magnetic core to increase the inductance and quality factor of inductors. Using parylene as substrates, these inductors became more flexible and biocompatible. For small scale inductors, by HFSS simulation, a maximum quality factor of 51.52 was achieved at 3.10 GHz. The inductance of inductors with magnetic core was enhanced by 3.3% than those with air core. As the width of the core increased from 25 μm to 100 μm, the inductance was also increased by 11.3% maximally. For large scale inductors fabricated, the tested maximum quality factor was 110 at 6 MHz. Based on the IC compatible fabrication process, these inductors could be used in wireless power transmission system for implantable medical devices.","Title: Convergence characteristics analysis on blind separation of DS-CDMA signals with ICA method\nYear: 2010\n\nAbstract: Blind estimation of information sequences and pseudo random sequences is of great importance for the security in DS-CDMA system, which remains a hot research topic in reconnaissance and supervision of wireless communication. In DS-CDMA system, the information sequences of different user's are independent and the pseudo random sequences are none correlation, thus independent component analysis (ICA) technology can be adopted to separate the DS-CDMA signals with little prior knowledge. Under non-cooperative situations, the interceptor could not aim at the beginning of the symbol accurately. The offset between the transmitter and the interceptor has great influence on the convergence characteristic of the blind separation algorithm of DS-CDMS signals with ICA method. Certain offsets deteriorate the convergence characteristic obviously. The relationship between the offset and the convergence characteristics is found out, which has great importance in choosing the offset in practice. The reason why certain offsets deteriorate the algorithm is analyzed from the idea of eigen value decomposition. The correctness of theory analysis is proved by the simulation results at last.","Title: VASP: virtualization assisted security monitor for cross-platform protection\nYear: 2011\n\nAbstract: Numerous operating systems have been designed to manage and control system resources with large and complicated features, so they need high security protection. However, previous security applications can not provide adequate protection due to the untrusted execution environment. Furthermore, these security strategies cannot support a universal cross-platform system security requirements. This paper presents VASP, a hypervisor based monitor which allows a trusted execution environment to monitor various malicious behaviors in the operating system. This is achieved by taking advantage of ×86 hardware virtualization and self-transparency technology, and providing a unified security protection to unmodified operating systems such as Linux and Windows. Our design is targeted at establishing a security monitor which resides completely outside of the target OS environment with a negligible overhead. According to the security analysis and performance experiment result, our approach can effectively protect applications and the kernel at a modest overhead of only 0.9% average in Windows XP and 2.6% average in Linux.","Title: SPAD: software protection through anti-debugging using hardware virtualization\nYear: 2011\n\nAbstract: Debugging could be a threat to system security when adopted by malicious attackers. The major challenges of software-only anti-debugging are compromised strategy and lack of self-protection. Leveraging hardware virtualization, we proposes a strategy of software protection through anti-debugging which imperceptibly monitors the debug event on a higher privilege level than the conventional kernel space. Our prototype can effectively prohibit the debugging behavior from selected popular debuggers in the replication experiment.","Title: HBSP: A Lightweight Hardware Virtualization Based Framework for Transparent Software Protection in Commodity Operating Systems\nYear: 2009\n\nAbstract: Commodity operating systems are usually large and complex, leading host-based security tools often provide inadequate protection against malware because execution environment for software is untrusted. As a result, most software currently uses various ways to defend malware attacks. However, these approaches not only raise the complexity of the software but also fail to offer an engrained security solution. The focal point in the software protection battle is how to protect effectively versus how to conceal the protector from untrusted OSes. This paper describes a lightweight, transparent and flexible architecture framework called HBSP (Hypervisor Based Software Protector)for software protection. HBSP, which is based on hardware virtualization extension technology such as Intel VT, and by taking advantage of Memory-Hiding strategy, resides completely outside of the target OS environment. Our security analysis and the performance experiment results demonstrate that HBSP effectively protects applications running on unmodified Windows XP, while the total overhead is only 0.25% in average.","Title: Neural Networks Based Image Recognition: A New Approach\nYear: 2007\n\nAbstract: In this paper, a new application algorithm for image recognition based on neural network has been pro-posed. The present algorithm including recognition algorithm and algorithm for training BP neural network can recognize continually changing large gray image. This algorithm has been applied to deflection measurement of bridge health monitoring, and achieved a great success.","Title: A scalable key management and clustering scheme for wireless ad hoc and sensor networks\nYear: 2008\n\nAbstract: This paper describes a scalable key management and clustering scheme for secure group communications in ad hoc and sensor networks. The scalability problem is solved by partitioning the communicating devices into subgroups, with a leader in each subgroup, and further organizing the subgroups into hierarchies. Each level of the hierarchy is called a tier or layer. Key generation, distribution, and actual data transmissions follow the hierarchy. The distributed, efficient clustering approach (DECA) provides robust clustering to form subgroups, and analytical and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility. Comparing with most other schemes, our approach is extremely scalable and efficient, provides more security guarantees, and is selective, adaptive and robust.","Title: Vis: Virtualization enhanced live forensics acquisition for native system.\nYear: 2012\n\nAbstract: Current live acquisition systems can obtain memory content of a running system, but they either fail to provide accurate native system physical memory acquisition at the given time point or require suspending the machine and altering the execution environment drastically. To address this issue, we propose Vis, a lightweight virtualization approach to provide accurate retrieval of physical memory content without disturbing the execution of the target native system. Our experimental results indicate that Vis is capable of reliably retrieving an accurate system image. Moreover, Vis accomplishes live acquisition in around 100 s, where previous remote live acquisition tools take hours and static acquisition takes days. On average, the performance reduction for the target system is 9.62%.","Title: A Multi-objective Cross-training Plan Based on NSGA-II.\nYear: 2013\n\nAbstract: The previous research on cross-training mainly focused on productive efficiency. However, enhancing labor's satisfaction of tasks is as much important as improving production performance. This paper addresses a new cross-training policy for an assembly cell from the point of view of humanization. A multi-objective 0-1 integer programming model is presented to implement the crosstraining policy for an assembly cell. The first objective works on getting to maximize average satisfaction degree, and the second objective seeks to minimize average paid salary, while determining which labors should be cross-trained on which tasks. Non-dominated sorting genetic algorithm (NSGA-II) is developed to solve the model. A series of computational experiments are proceeded to explore the impact of three factors on cross-training, including labor's preference structure, labor's salary structure, and task redundancy. The results indicate that the balanced preference structure is better than the extreme one, the non-uniform salary structure is better than the uniform one, and the smaller task redundancy is better than the bigger one under various scenarios in the paper. Those insights can be used to direct the managers of human resource to choose the candidates for cross-training. © 2013 ACADEMY PUBLISHER.","Title: Fall detection in a smart room by using a fuzzy one class support vector machine and imperfect training data\nYear: 2011\n\nAbstract: In this paper, we propose an efficient and robust fall detection system by using a fuzzy one class support vector machine based on video in formation. Two cameras are used to capture the video frames from which the features are extracted. A fuzzy one class support vector machine (FOCSVM) is used to distinguish falling from other activities, such as walking, sitting, standing, bending or lying. Compared with the traditional one class support vector machine, the FOCSVM can obtain a more accurate and tight decision boundary under a training dataset with outliers. From real video sequences, the success of the method is confirmed with less non-fall samples being misclassified as falls by the classifier under an imperfect training dataset.","Title: D-type anticipatory iterative learning control for a class of inhomogeneous heat equations\nYear: 2013\n\nAbstract: In this paper, a D-type anticipatory iterative learning control (ILC) scheme is applied to the boundary control of a class of inhomogeneous heat equations, where the heat flux at one side is the control input while the temperature measurement at the other side is the control output. By transforming the inhomogeneous heat equation into its integral form and exploiting the properties of the embedded Jacobi Theta functions, the learning convergence of ILC is guaranteed through rigorous analysis, without any simplification or discretization of the 3D dynamics in the time, space as well as iteration domains. The adopted ILC scheme makes full use of the process repetition and deals with state-independent or state-dependent uncertainties. Meanwhile, due to the feedforward characteristic of ILC, the proposed scheme not only makes anticipatory compensation possible to overcome the heat conduction delay in boundary output tracking, but also eliminates the gain margin limitation encountered in feedback control. In the end, an illustrative example is presented to demonstrate the performance of the proposed ILC scheme.","Title: Hypervisor-based protection of sensitive files in a compromised system\nYear: 2012\n\nAbstract: One of the most fundamental issues in computer security is protecting sensitive files from unauthorized access. Traditional file protection tools run inside the target operating system, which hosts sensitive files. This makes previous approaches vulnerable in face of a compromised OS. To address this limitation, recent approaches seek for a good isolation by putting file system into a dedicated virtual machine or by using a network file system. However, they suffer a sharp increase in trusted computing base size which degrades their reliability. In this paper, we present Filesafe, a special purpose hy-pervisor aimed at protecting sensitive files in a compromised operating system. It bridges the semantic gap between guest OS and hypervisor by reconstructing file hierarchy from raw data, which incurs no runtime overhead. By enforcing security policies created in hypervisor, Filesafe could prevent sensitive files from unauthorized access even if they have kernel privileges in guest OS. We have implemented a proof-of-concept prototype on Windows XP with FAT32 file system. Furthermore, we evaluate Filesafe's performance and code size to demonstrate it is practical in real world scenarios.","Title: Enhanced Privilege Separation for Commodity Software on Virtualized Platform\nYear: 2010\n\nAbstract: Conventional privilege separation can effectively reduce the TCB size by granting privilege to only the privileged compartments. However, since they this approach relies on process isolation to ensure security assurance, malware exploiting against kernel components can easily compromise. Meanwhile, the frequent inter-process communications between separated processes inevitably incur notable overhead. To ameliorate these problems, we propose to perform privilege separation without partitioning application into two processes. Instead, we leverage virtualization to enforce the isolation of sensitive portions from other untrusted code. The virtual machine monitor intercepts all the code context switches transparently without requiring the application to explicitly use IPC as privilege context transition. We have implemented a prototype of our system, named Coir, based on commodity hypervisor Xen. Evaluation of our prototype includes a real-world remote control application, which is partitioned and protected in Coir-enabled hypervisor on unmodified Windows XP. We discuss the isolation strength as well as the performance penalty of our system based on the practical case.","Title: Mobility Resistant Clustering in Multi-Hop Wireless Networks\nYear: 2006\n\nAbstract: This paper presents a Distributed Efficient Clustering Approach (DECA) for mobility-resistant and energy-efficient clustering in multi-hop wireless networks. The clusterheads cover the whole network and each node in the network can exclusively determine the single cluster it belongs. DECA is fully distributed, each node transmits only one message during clustering operation, and the algorithm terminates in deterministic time without iterations. Theoretical results show the correctness of DECA, and extensive simulation results demonstrate that DECA is energy-efficient and robust against node mobility.","Title: Study On Dynamic Variation Regularities Of Regional Groundwater Depth Based On Complexity Diagnosis\nYear: 2011\n\nAbstract: In the course of analyzing and forecasting regional groundwater depth, its variation process complexity was ignored in the past, so that it was difficult to realize scientific management of groundwater resources. Aiming at the aforesaid defect, taking Jiansanjiang branch bureau as research platform, this paper diagnosed the complexity of each monthly groundwater depth series through using complexity measurement methods which include wavelet theory, fractal theory, Approximate Entropy and so on. The comprehensive measurement analysis results show that the complexity order of monthly groundwater depth series in the eighth district of Farm Nongjiang is highest in four farms of northern region. On that basis, the most complexity groundwater depth series combination stochastic forecasting model based on wavelet transform in northern region of Jiansanjiang branch bureau was set up. The model forecasting results show that local annual mean groundwater depth will be in a state of fluctuant lifting, and have considerable gap in comparison to groundwater ideal depth in the future. So, local government should reinforce the scientific management of groundwater. The research achievements break through the traditional study paradigm of hydrological forecasting, provide a research mode for studying regional hydrologic process, and provide scientific evidence for sustainable utilizing regional groundwater resources.","Title: A relativistic extension of the complex scaling method using oscillator basis functions\nYear: 2010\n\nAbstract: We develop the complex scaling method within the relativistic framework by expanding the Dirac spinors in the complete set of eigensolutions of a harmonic oscillator potential, and present the theoretical formalism of describing the discrete bound and resonant states on the same footing. Based on a well established and frequently used model, we demonstrate the utility and applicability of the extended method and examine the stability of the results with respect to the variations of the parameters of the model. Satisfactory agreements are found for all the calculated results in comparison with some other calculations in references. Especially, the present calculation in the nonrelativistic limit gives a consistent result with that in the nonrelativistic calculation.","Title: Investigating the pattern of syndrome based on the difference of symptom network in depression\nYear: 2013\n\nAbstract: In TCM theory, the syndrome is crucial to diagnose diseases and treat patients. In syndrome identification, the relation of symptoms usually correlates with syndrome and represents the pattern of syndrome at symptomatic level. Hence, we learn models for classifying syndromes in depression using 4 different algorithms, which are naive Bayes, Bayes network, SVM and C4.5. From the results of classification, we find that the dependence of symptoms has something to do with the accuracies of syndrome classification. Then, 8 symptom networks corresponding to depression and 7 syndromes are constructed to explore the interaction profile of symptoms under syndrome. By comparing syndrome-specific symptom network to the base network of depression, we discover the enriched edges and different nodes to represent the pattern of each syndrome. Literature and symptom ranking by Fisher score demonstrate the correctness of the different nodes selected through network comparison. After all, the enriched edges and different nodes associated with a given syndrome reveal the pattern of that syndrome at symptomatic level.","Title: Output feedback adaptive iterative learning control for nonlinear discrete-time systems with unknown control directions\nYear: 2012\n\nAbstract: An adaptive iterative learning control method is developed for a class of high-order nonlinear output feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. The n-step ahead predictor approach is employed to estimate the future outputs. The discrete Nussbaum gain method is incorporated into the control design to deal with the lack of a priori knowledge of the control directions. The proposed control algorithm guarantees that the tracking error converges to zero asymptotically along the iterative learning axis except for the beginning outputs affected by the random initial conditions with all the signals in the controlled system bounded. A numerical simulation is carried out to demonstrate the effectiveness of the proposed control laws.","Title: Schedulability Analysis for Distributed Systems Using Network of Action Automata and Environment Automata\nYear: 2011\n\nAbstract: Recently, several formal approaches have been presented to address the problem of schedulability analysis of real-time systems by some varieties of timed automata, e.g., UPPAAL and TIMES. In this paper, we consider a more general and complicated formal computational model for distributed systems. To analyze the schedulability of tasks within this model by automata theory, we present a model, action automata, which is a class of suspension automata, to describe the execution semantics of tasks, we also define an environment model, environment automata, to describe the arrival patterns of tasks. One main result gives the scheduling policies under which the schedulability can be analyzed by our method correctly. To achieve this result, we translate the schedulability analysis to the reach ability analysis of the network of action automata and environment automata. Therefore, another main result of this paper is that we prove the reach ability of action automata is decidable. Based on these conclusions, we implement a prototype tool for schedulability analysis and test its performance under EDF policy.","Title: Logic switching based online periodic adaptive learning control algorithm dealing with unknown period and bound of the uncertain parameter\nYear: 2013\n\nAbstract: In this paper, a switching periodic adaptive control approach is proposed for a class of nonlinear systems with periodic parametric uncertainties whose period and bound are not known. A fully saturated periodic adaptation law is utilized to estimate the unknown parameter vector. A logic switching based algorithm is provided to tune the unknown period and bound of the parameter vector online. By virtue of Lyapunov energy function, asymptotic convergence can be ensured for the tracking error and all the signals in the system is guaranteed bounded. A simulation to a one-link robotic manipulator is carried out to demonstrate the effectiveness of the switching learning control algorithm.","Title: SPAD: Software Protection Through Anti-Debugging Using Hardware-Assisted Virtualization.\nYear: 2012\n\nAbstract: Debugging usually facilitates the dynamic analysis of runtime application for software development. Yet it can also be a threat to system security when adopted by malicious attackers, and hence anti-debugging becomes valuable. The major challenges of software-only anti-debugging are the compromised strategy and lack of self-protection. This paper proposes software protection through anti-debugging (SPAD), a technique that imperceptibly monitors the behavior of debuggers. Leveraging hardware virtualization, SPAD detects debugging behavior by intercepting debug events on a higher privilege level than the conventional kernel space. Our experiment shows that SPAD can effectively prohibit the debugging behavior from 8 popular debuggers while the overhead incurred is 1.14%.","Title: A digital authentication watermarking scheme for JPEG images with superior localization and security\nYear: 2007\n\nAbstract: The drawbacks of the current authentication watermarking schemes for JPEG images, which are inferior localization and the\n security flaws, are firstly analyzed in this paper. Then, two counterferiting attacks are conducted on them. To overcome these\n drawbacks, a new digital authentication watermarking scheme for JPEG images with superior localization and security is proposed.\n Moreover, the probabilities of tamper detection and false detection are deduced under region tampering and collage attack\n separately. For each image block, the proposed scheme keeps four middle frequency points fixed to embed the watermark, and\n utilizes the rest of the DCT coefficients to generate 4 bits of watermark information. During the embedding process, each\n watermark bit is embedded in another image block that is selected by its corresponding secret key. Since four blocks are randomly\n selected for the watermark embedding of each block, the non-deterministic dependence among the image blocks is established\n so as to resist collage attack completely. At the receiver, according to judging of the extracted 4 bits of watermark information\n and the corresponding 9-neighbourhood system, the proposed scheme could discriminate whether the image block is tampered or\n not. Owing to the diminishing of false detection and the holding of tamper detection, we improve the accuracy of localization\n in the authentication process. Theoretic analysis and simulation results have proved that the proposed algorithm not only\n has superior localization, but also enhances the systematic security obviously.","Title: Research on Vehicle Magneto-rheological Suspensions Vibration Control and Test\nYear: 2006\n\nAbstract: A vehicle with independent magneto-rheological (MR) suspensions is regarded as a fleetly moving robot. To decrease MR suspension model simplification errors and to enhance the effect of MR suspension complicated vibration control, a hierarchical intelligent control (HIC) system is proposed. There are four independent local adaptive fuzzy (AF) controllers in control level and one coordination controller in coordination level. To restrain vibration of vehicle sprung mass and un-sprung mass, at the control level, a semi-active AF controller is designed for each MR suspension system, which can online adjust quantization factors and scale factor of fuzzy controller by human-simulation intelligent parameter modifying algorithm. At the coordination level, a controller is designed to coordinate the four local independent AF controllers, by adjusting their output parameters according to vehicle running attitude and characteristics of MR suspensions in different conditions. To validate the real results of hierarchical control, a MR suspension control and test system is set up and implemented on a mini automotive vehicle, which is equipped with four controllable MR dampers. Road tests under various conditions indicate that the HIC system can effectively reduce vertical vibration, improve the ride comfort, handle stability of vehicle, and show adaptiveness and robustness.","Title: An anti-jamming framework of spread spectrum communications with ICA\nYear: 2012\n\nAbstract: When jamming signal is strong enough, the performance of spread spectrum (SS) communications will decline quickly. According to the independence between the SS signal and the jamming signal in baseband, a novel anti-jamming framework of SS communication with independent component analysis (ICA) is proposed in this paper. This anti-jamming framework utilizes the particular structure of SS communications to reduce the degree of the received mixed signals. Because of the advantage of ICA, no prior knowledge of the jamming signal is needed any more, so the operations such as detection and parameter estimation of the jamming signal can be saved. The proposed anti-jamming framework deals with common jamming signals in a unifying framework, which needs not to switch among several anti-jamming techniques corresponding to different type of the jamming. The validity of the proposed method is proved by numerical simulation results at last.","Title: Contactless RF MEMS switch using PZT actuation\nYear: 2013\n\nAbstract: RF MEMS devices are competitive for handling high frequency microwave signals. In comparison to semiconductor devices, the performance of RF MEMS devices is highly linear, minimizing signal distortion. A contactless piezoelectric RF MEMS switch has been designed and simulated. Due to the use of a contactless design based on variable capacitance the reliability issues affecting contacting-type MEMS switches are avoided. The structure is piezoelectrically actuated using a sputtered lead zirconate titanate (PZT) layer. Finite element simulation has been conducted to optimize the structure. Electrical simulation predicts that, by achieving an on-off capacitance ratio greater than 10, isolation will exceed 15 dB over the frequency range from 4 to 15 GHz. Preliminary isolation measurements on fabricated devices without the actuating layer showed 26 dB isolation at 4 GHz, similar to that modeled, although isolation did not decrease by the modeled trend at high frequencies approaching 15 GHz. © 2013 IEEE.","Title: Effect of RF sputtering parameters on PZT crystal growth\nYear: 2013\n\nAbstract: Lead zirconate titanate(PZT) due to its large polarization, large dielectric constant and good piezoelectric performance has become popular in a wide range of applications in MEMS field. The prevailing technique for PZT deposition is sol-gel method, but the stability of solution and repeated coating can't be precisely controlled. Sputtering technique is used in this work for its relatively simple fabrication process, uniform thickness. In this work, PZT films are sputtered on Pt/Ti/SiO2/Si substrate prior to annealing. PZT preferential orientation is highly depend on the sputtering parameters. X-ray diffraction(XRD) analysis has been performed to compare the crystal growth. TiO2 seed layer is also introduced in this work.","Title: A new magnetorheological elastomer isolator in shear - Compression mixed mode\nYear: 2013\n\nAbstract: A new magnetorheological elastomer (MRE) isolator in shear-compression mixed mode is designed in this paper. Two pieces of MRE fabricated with different dimension are utilized in the isolator. The one MRE operates on compressive mode, and the other operates on shear mode. A finite element method magnetic (FEMM) package is used to analyze the magnetic circuit system, and a test system is established to obtain the vibration performance curves of MRE isolator. It is found that the natural frequency of MRE isolator changes greatly with variable current applied, and the amptitude of vibration is attenuated widely. Compared with the natural frequency of 0A, the increment of natural frequency is up to 103% with applied current reaches to 1.5A. The stiffness and damping coefficient of MRE isolator are identified by the experiment. The results show that the variable range of stiffness of MRE isolators with two operating modes is greater than that of single mode. © 2013 IEEE.","Title: Research on role-network model for E-Government Affairs\nYear: 2005\n\nAbstract: Constructing an E-Gov Affairs system requires complex systematic engineering, and it is difficult to be successful. Meanwhile, it is a very practical and independent action, and it is necessary to have a theoretic model suitable for an E-Gov Affairs environment. In this paper, based on the analysis of characteristics of E-Government Affairs, a role network model is proposed along with its relation to other relative models discussed. Finally, a formalization description of this model is given. © 2005 IEEE.","Title: Modeling the commuting travel activities within historic districts in chinese cities\nYear: 2014\n\nAbstract: The primary objective of this study is to analyze the characteristics of commuting activities within the historical districts in cities of China. The impacts of various explanatory variables on commuters' travels are evaluated using the structural equation modeling (SEM) approach. The household survey was conducted in the historical districts in Yangzhou, China. Based on the data, various individual and household attributes were considered exogenous variables, while the subsistence activity characteristics, travel times, numbers of three typical home-based trip chains, trip chains, and travel mode were considered as the endogenous variables. Commuters in our study were classified into two main groups according to their working location, which were the commuters in the historic district and those out of the district. The modeling results show that several individual and household attributes of commuters in historic district have significant impacts on the characteristics of travel activities. Additionally, the characteristics of travel activities within the two groups are quite different, and the contributing factors related to commuting travels are different as well.","Title: A Virtualization Based Monitoring System for Mini-intrusive Live Forensics\nYear: 2015\n\nAbstract: Digital evidences hold great significance for governing cybercrime. Unfortunately, previous acquisition tools were troubled by either the shortage of suspending the target system's running or the security of the acquisition tools themselves, thus the correctness and accuracy of their obtained evidences cannot be guaranteed. In this paper, we propose VAIL, a novel virtualization based monitoring system for mini-intrusive live forensics, which employs hardware assisted virtualization technique to gather integrated information from the native computer system. Meanwhile, the execution of the target system will not be interrupted and VAIL keeps immune to attacks from the target system. We have implemented a proof-of-concept prototype that has been validated with a Windows guest system. The experimental results show that VAIL can obtain comprehensive digital evidences from the target system as designed, including the CPU state, the physical memory content, and the I/O activities. And on average, VAIL only introduces 4.21 % performance overhead to the target system, which proves that VAIL is practical in real commercial environments.","Title: An unsupervised acoustic fall detection system using source separation for sound interference suppression.\nYear: 2015\n\nAbstract: We present a novel unsupervised fall detection system that employs the collected acoustic signals (footstep sound signals) from an elderly person׳s normal activities to construct a data description model to distinguish falls from non-falls. The measured acoustic signals are initially processed with a source separation (SS) technique to remove the possible interferences from other background sound sources. Mel-frequency cepstral coefficient (MFCC) features are next extracted from the processed signals and used to construct a data description model based on a one class support vector machine (OCSVM) method, which is finally applied to distinguish fall from non-fall sounds. Experiments on a recorded dataset confirm that our proposed fall detection system can achieve better performance, especially with high level of interference from other sound sources, as compared with existing single microphone based methods.","Title: A Single-Channel Ica-R Method For Speech Signal Denoising Combining Emd And Wavelet\nYear: 2014\n\nAbstract: According to the problem of speech signal denoising, we propose a novel method in this paper, which combines empirical mode decomposition (EMD), wavelet threshold denoising and independent component analysis with reference (ICA-R). Because there is only one mixed recording, it is a single-channel independent component analysis (SCICA) problem in fact, which is hard to solve by traditional ICA methods. EMD is exploited to expand the single-channel received signal into several intrinsic mode functions (IMFs) in advance, therefore traditional ICA of multi-dimension becomes applicable. First, the received signal is segmented to reduce the processing delay. Secondly, wavelet thresholding is applied to the noise-dominated IMFs. Finally, fast ICA-R is introduced to extract the object speech component from the processed IMFs, whose reference signal is constructed by assembling the high-order IMFs. The simulations are carried out under different noise levels and the performance of the proposed method is compared with EMD, wavelet thresholding, EMD-wavelet and EMD-ICA approaches. Simulation results indicate that the proposed method exhibit superior denoising performance especially when signal-to-noise ratio is low, with a half shorter running time.","Title: vGASA: Adaptive Scheduling Algorithm of Virtualized GPU Resource in Cloud Gaming\nYear: 2014\n\nAbstract: As the virtualization technology for GPUs matures, cloud gaming has become an emerging application among cloud services. In addition to the poor default mechanisms of GPU resource sharing, the performance of cloud games is inevitably undermined by various runtime uncertainties such as rendering complex game scenarios. The question of how to handle the runtime uncertainties for GPU resource sharing remains unanswered. To address this challenge, we propose vGASA, a virtualized GPU resource adaptive scheduling algorithm in cloud gaming. vGASA interposes scheduling algorithms in the graphics API of the operating system, and hence the host graphic driver or the guest operating system remains unmodified. To fulfill the service level agreement as well as maximize GPU usage, we propose three adaptive scheduling algorithms featuring feedback control that mitigates the impact of the runtime uncertainties on the system performance. The experimental results demonstrate that vGASA is able to maintain frames per second of various workloads at the desired level with the performance overhead limited to 5-12 percent.","Title: Visualizing and analyzing dynamic meteorological data with virtual globes: A case study of tropical cyclones.\nYear: 2015\n\nAbstract: Visualization is an important component of the evaluation of meteorological models, forecasting research, and other applications. With advances in computing power, the volume of meteorological data generated by geoscience and climate researchers has been steadily increasing. The emerging technique of virtual globes has been regarded as an ideal platform for visualizing larger geospatial data over the Internet. To visualize and analyze meteorological data with the new virtual globes, this paper proposes a systematic meteorological data visualization (MDV) framework in World Wind, an open-source virtual globe. The key technologies, including a hierarchical octree-based multiresolution data organization, data scheduling, level of detail (LOD) and rendering are described in detail. The framework is then applied to a practical tropical cyclone simulation, including flow vectors, particle tracking, cross-sectional analysis, streamlines, pathway animation, and volume rendering. The results show that virtual globes are effective tools for meteorological data visualization and analysis.","Title: VGRIS: Virtualized GPU Resource Isolation and Scheduling in Cloud Gaming\nYear: 2014\n\nAbstract: To achieve efficient resource management on a graphics processing unit (GPU), there is a demand to develop a framework for scheduling virtualized resources in cloud gaming. In this article, we propose VGRIS, a resource management framework for virtualized GPU resource isolation and scheduling in cloud gaming. A set of application programming interfaces (APIs) is provided so that a variety of scheduling algorithms can be implemented within the framework without modifying the framework itself. Three scheduling algorithms are implemented by the APIs within VGRIS. Experimental results show that VGRIS can effectively schedule GPU resources among various workloads.","Title: Dancing with Giants: Wimpy Kernels for On-Demand I/O Isolation\nYear: 2015\n\nAbstract: To be trustworthy, security-sensitive applications must be formally verified and hence small and simple, i.e., wimpy. Thus, they cannot include a variety of basic services available only in large and untrustworthy commodity systems, i.e., in giants. Hence, wimps must securely compose with giants to survive on commodity systems, i.e., rely on giants' services but only after efficiently verifying their results. This paper presents a security architecture based on a wimpy kernel that provides on-demand isolated I/O channels for wimp applications, without bloating the underlying trusted computing base. The size and complexity of the wimpy kernel are minimized by safely outsourcing I/O subsystem functions to an untrusted commodity operating system and exporting driver and I/O subsystem code to wimp applications. Using the USB subsystem as a case study, this paper illustrates the dramatic reduction of wimpy-kernel size and complexity, e.g., over 99% of the USB code base is removed. Performance measurements indicate that the wimpy-kernel architecture exhibits the desired execution efficiency.","Title: Feedback nonlinear discrete-time systems\nYear: 2014\n\nAbstract: In this paper, we design an adaptive iterative learning control method for a class of high-order nonlinear output feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. An n-step ahead predictor approach is employed to estimate future outputs. The discrete Nussbaum gain method is incorporated into the control design to deal with unknown control directions. The proposed control algorithm ensures that the tracking error converges to zero asymptotically along the iterative learning axis except for the beginning outputs affected by random initial conditions. A numerical simulation is carried out to demonstrate the efficacy of the presented control laws.","Title: Direct heuristic dynamic programming method for power system stability enhancement\nYear: 2014\n\nAbstract: In this paper a neural network-based approximate dynamic programming method, namely direct heuristic dynamic programming (direct HDP), is applied to power system stability control. Direct HDP is a learning and approximation based approach to address nonlinear system control under uncertainty. In the present paper, real-time system responses provided by wide area measurement system (WAMS) are used to construct such controllers which are uniquely tailored for the problems under consideration. In addition, the controller learning objective is formulated as a reward function that reflects global characteristics of the power system low frequency oscillation under the consideration of coupling effect among system components. The contribution of the paper includes a convergence proof of the direct HDP algorithm using an LQR framework, as well as case study to illustrate the proposed learning control algorithm. The case study aims at providing a new solution to a difficult large scale system coordination problem where the China Southern Power Grid is used for.","Title: A novel ICA-based frequency hopping receiver with correlated jamming suppression\nYear: 2012\n\nAbstract: Compared with common jamming techniques, the correlated jamming is much efficient against the frequency hopping (FH) communication system. Because of the similarity between the correlated jamming signal and the FH signal, it is very difficult for common anti-jamming techniques to deal with such correlated jamming. According to the independence between the payload of the correlated jamming signal and the victim FH signal, a novel independent component analysis (ICA) based receiver is proposed in this paper. Two antennas are introduced at the receiver end. The received signals are despread firstly to reduce the dimension of mixing matrix. Then ICA is utilized to recover the useful signal from two baseband signals. The numerical simulation results indicate that the proposed ICA-based receiver is robust to the correlated jamming. Even when the power of correlated jamming is very strong, the proposed receiver can still improve the BER performance greatly.","Title: Detecting Bots in Follower Markets.\nYear: 2014\n\nAbstract: Along with the widely using of microblog, third party services such as follower markets sell bots to customers to build fake influence and reputation. However, the bots and the customers that have large numbers of followers usually post spam messages such as promoted messages, messages containing malicious links. In this paper, we propose an effective approach for bots detection based on interaction graph model and BP neural network. We build an interaction graph model based on user interaction and design robust interaction-based features. We conduct a comprehensive set of experiments to evaluate the proposed features using different machine learning classifiers. The results of our evaluation experiments show that BP neural network classifier using our proposed features can be effectively used to detect bots compared to other existing state-of-the-art approaches.","Title: Deep learning for posture analysis in fall detection\nYear: 2014\n\nAbstract: We propose a novel computer vision based fall detection system using deep learning methods to analyse the postures in a smart home environment for detecting fall activities. Firstly, background subtraction is employed to extract the foreground human body. Then the binary human body images form the input to the classifier. Two deep learning approaches based on a Boltzmann machine and deep belief network are compared with a support vector machine approach. The final decision on the occurrence of a fall is made on the basis of combining the classifier output with certain contextual rules. Evaluations are performed on recordings from a real home care environment, in which 15 people create 2904 postures.","Title: A dynamic prognosis algorithm in distributed fault tolerant model predictive control\nYear: 2014\n\nAbstract: This paper presents a dynamic prognosis algorithm in distributed fault tolerant model predictive control (DFTMPC). The dynamic prognosis, which means predicting the trajectories of process variables under distributed model predictive control, is performed when a fault is diagnosed and several candidate reconfigured controls are proposed. Then, the dynamic prognosis is utilized to check whether the candidate reconfigured controls are able to drive the system to the new operating conditions and to evaluate the performance during the transition period. Thus, the most suitable candidate reconfigured controller is selected and its feasibility is ensured without using a Lyapunov function that is difficult to obtain for large-scale systems. On the other hand, the on-line computation burden of the prognosis algorithm is moderate under the assumption that the sets of active constraints in non-faulty subsystems remain the same as they are at the nominal operating conditions. Thus, the dynamic prognosis for DMPC is aimed to improve the applicability of the existing fault tolerant methods to large-scale systems.","Title: A Multimodal Approach to Blind Source Separation of Moving Sources\nYear: 2010\n\nAbstract: A novel multimodal approach is proposed to solve the problem of blind source separation (BSS) of moving sources. The challenge of BSS for moving sources is that the mixing filters are time varying; thus, the unmixing filters should also be time varying, which are difficult to calculate in real time. In the proposed approach, the visual modality is utilized to facilitate the separation for both stationary and moving sources. The movement of the sources is detected by a 3-D tracker based on video cameras. Positions and velocities of the sources are obtained from the 3-D tracker based on a Markov Chain Monte Carlo particle filter (MCMC-PF), which results in high sampling efficiency. The full BSS solution is formed by integrating a frequency domain blind source separation algorithm and beamforming: if the sources are identified as stationary for a certain minimum period, a frequency domain BSS algorithm is implemented with an initialization derived from the positions of the source signals. Once the sources are moving, a beamforming algorithm which requires no prior statistical knowledge is used to perform real time speech enhancement and provide separation of the sources. Experimental results confirm that by utilizing the visual modality, the proposed algorithm not only improves the performance of the BSS algorithm and mitigates the permutation problem for stationary sources, but also provides a good BSS performance for moving sources in a low reverberant environment.","Title: Multimodal blind source separation for moving sources based on robust beamforming\nYear: 2011\n\nAbstract: An improvement in the multimodal approach to the problem of blind source separation (BSS) of moving sources is proposed. The challenge of BSS for moving sources is that the mixing filters are time varying. Thus the unmixing filters should also be time varying, which are difficult to calculate from only statistical information avail able from limited number of audio samples. Therefore, in the pro posed approach a robust least square frequency invariant data independent (RLSFIDI) beamformer is implemented to perform real time speech enhancement and provide separation of the moving sources. Direction of arrival information of the sources is obtained from the visual 3-D tracker based on a Markov Chain Monte Carlo particle filter (MCMC-PF). The uncertainties in source localization and direction of arrival information are controlled by using convex optimization approach in the beamformer design. This provides robust ness with a wider main lobe for source of interest (SOI) and wider attenuation pattern to block the interference. In addition, white noise gain (WNG) constraint is used to control the beamformer sensitivity. Experimental results show that by utilizing RLSFIDI beamformer a significant improvement in BSS performance for moving sources is achieved in a low reverberant environment.","Title: Graphics processing unit-based dynamic volume rendering for typhoons on a virtual globe.\nYear: 2015\n\nAbstract: Typhoons are usually accompanied by strong winds, heavy rain, storm surges and other disastrous events, and they are the most severe weather phenomena in the western part of the North Pacific Ocean. Visualisation is a key technology for analysing and presenting climate simulations and observations together with related social and ecological data. Virtual globes are a logical platform for visualising such geospatial data via the Internet. To implement interactive visualisation of typhoon data within virtual globes, this study provides a 3D texture-mapping algorithm to render volume textures on a globe. In addition, a systematic framework is proposed in which a hierarchical octree-based multiresolution data structure is implemented to organise the large volume dataset, and a graphics processing unit-based dynamic interpolation approach is proposed to obtain a smooth effect. Finally, the structure is combined with a level of detail strategy to enable the rendering of dynamic volumetric data at an acceptable interactive frame rate. To demonstrate the capabilities of this framework, data for a simulated typhoon event were rendered in World Wind, an open-source virtual globe. The experimental results demonstrate that the application of the proposed strategies can result in an interactive visualisation performance that renders typhoon data on virtual globes.","Title: Anomaly Detection in Microblogging via Co-Clustering.\nYear: 2015\n\nAbstract: Traditional anomaly detection on microblogging mostly focuses on individual anomalous users or messages. Since anomalous users employ advanced intelligent means, the anomaly detection is greatly poor in performance. In this paper, we propose an innovative framework of anomaly detection based on bipartite graph and co-clustering. A bipartite graph between users and messages is built to model the homogeneous and heterogeneous interactions. The proposed co-clustering algorithm based on nonnegative matrix tri-factorization can detect anomalous users and messages simultaneously. The homogeneous relations modeled by the bipartite graph are used as constraints to improve the accuracy of the co-clustering algorithm. Experimental results show that the proposed scheme can detect individual and group anomalies with high accuracy on a Sina Weibo dataset.","Title: Optimal Design Of A Multi-Server Queueing System With Delay Information\nYear: 2016\n\nAbstract: Purpose - The purpose of this paper is to provide a framework for the optimal design of queueing systems of call centers with delay information. The main decisions in the design of such systems are the number of servers, the appropriate control to announce delay anticipated.Design/methodology/approach - This paper models a multi-server queueing system as an M/M/S + M queue with customer reactions. Based on customer psychology in waiting experiences, a number of different service-level definitions are structured and the explicit computation of their performance measures is performed. This paper characterizes the level of satisfaction with delay information to modulate customer reactions. Optimality is defined as the number of agents that maximize revenues net of staffing costs.Findings - Numerical studies show that the solutions to optimal design of staffing levels and delay information exhibit interesting differences, especially U-shaped curve for optimal staffing level. Experiments show how call center managers can determine economically optimal anticipated delay and number of servers so that they could control the trade-off between revenue loss and customer satisfaction.Originality/value - Many results that pertain to announcing delay information, customer reactions, and links to satisfaction with delay information have not been established in previous studies, however, this paper analytically characterizes these performance measures for staffing call centers.","Title: Discrete-Time Adaptive Iterative Learning Control For High-Order Nonlinear Systems With Unknown Control Directions\nYear: 2013\n\nAbstract: An adaptive iterative learning control method is proposed for a class of nonlinear strict-feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. An n-step ahead predictor approach is employed to estimate the future states in the control design. Discrete Nussbaum gain method is utilised to deal with the lack of a priori knowledge of control directions. The proposed control algorithm guarantees the boundedness of all the signals in the controlled system. The tracking error converges to zero asymptotically along the iterative learning axis except for beginning states affected by random initial conditions. The effectiveness of the proposed control scheme is verified through numerical simulation.","Title: Determination of dominant weather parameters on reference evapotranspiration by path analysis theory\nYear: 2016\n\nAbstract: •Path theory is a new valid method for selecting dominant factor affecting ET0.•ET0 could be accurately estimated by only two climate factors.•Sunshine duration has strongest effect on ET0.•Combination of path analysis and ANN has accuracy in ET0 estimation.•Only two stations’ ET0 estimation models can be universalized in South China.","Title: The experimental study on vibration characteristics of MR seat suspension system\nYear: 2013\n\nAbstract: Effects of damping coefficient and spring stiffness on the transfer characteristics of the seat suspension system is studied. Based on the designed magneto-rheological (MR) seat suspension, the vibration characteristic experiment system is set up. Considering the change of damping and stiffness of MR damper caused by current, the vibration characteristics experiment about the seat suspension system is made. The results show that increasing the input current can reduce the transmissibility of the seat suspension system before the 1st order resonance frequency, and it presents a strong controllability. Meanwhile, it verifies the correctness of the theoretical simulation from the point of the experiment. © 2013 IEEE.","Title: A performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control\nYear: 2015\n\nAbstract: This paper presents a performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control for large-scale systems. After the fault has been detected and diagnosed, several controller reconfigurations are proposed as candidate corrective actions for fault compensation. The solution of a set of constrained optimization problems with different actuator and setpoint reconfigurations is derived by means of an original approach, exploiting the information on the active constraints in the non-faulty subsystems. Thus, the global optimization problem is split into two optimization subproblems, which enable the online computational burden to be greatly reduced. Subsequently, the performances of different candidate controller reconfigurations are compared, and the better performing one is selected and then implemented to compensate the fault effects. Efficacy of the proposed approach has been shown by applying it to the benzene alkylation process, which is a benchmark process in distributed model predictive control. (C) 2015 Elsevier Ltd. All rights reserved.","Title: A Robust student's-t distribution PHD filter with OCSVM updating for multiple human tracking\nYear: 2015\n\nAbstract: We propose a novel robust probability hypothesis density (PHD) filter for multiple target. tracking in an enclosed environment, where a one-class support vector machine (OCSVM) is used in the update step for combining different human features to mitigate the effect of measurement noise on the calculation of particle weights. A Student's-t distribution is employed to improve the robustness of the filters whose tail is heavier than the Gaussian distribution and thus has the potential to cover more widely-spread particles. The OCSVM is trained based on both colour and oriented tzradient (HOG) histogram features and then used to mitigate the measurement noise from the particle selection step, thereby improve the tracking performance. To evaluate the proposed PHD filter, we employed two sequences from the CAVIAR dataset and used the optimal subpattern assignment (OSPA) method as an objective measure. The results show that the proposed robust PHD filter outperforms the traditional PHD filter.","Title: Trusted Display on Untrusted Commodity Platforms\nYear: 2015\n\nAbstract: A trusted display service assures the confidentiality and authenticity of content output by a security-sensitive application and thus prevents a compromised commodity operating system or application from surreptitiously reading or modifying the displayed output. Past approaches have failed to provide trusted display on commodity platforms that use modern graphics processing units (GPUs). For example, full GPU virtualization encourages the sharing of GPU address space with multiple virtual machines {\\\\em without} providing adequate hardware protection mechanisms; e.g., address-space separation and instruction execution control. This paper proposes a new trusted display service that has a minimal trusted code base and maintains full compatibility with commodity computing platforms. The service relies on a GPU separation kernel that (1) defines different types of GPU objects, (2) mediates access to security-sensitive objects, and (3) emulates object whenever required by commodity-platform compatibility. The separation kernel employs a new address-space separation mechanism that avoids the challenging problem of GPU instruction verification without adequate hardware support. The implementation of the trusted-display service has a code base that is two orders of magnitude smaller than other similar services, such as those based on full GPU virtualization. Performance measurements show that the trusted-display overhead added over and above that of the underlying trusted system is fairly modest.","Title: Research of an improved algorithm for Chinese word segmentation dictionary based on double-array Trie-tree\nYear: 2013\n\nAbstract: Chinese word segmentation dictionary based on the double-array Trie-tree has higher search efficiency,but the dynamic insertion consumes a lot of time.Therefore,an improved algorithm(iDAT)based on double-array Trie-tree for Chinese word segmentation dictionary is proposed.The nodes with more branches are handled while the original dictionary is being initialized.After the initialization,a Hash process is performed on the index values of empty sequence in base array.The final Hash table stores the sum of the empty sequences before the current empty sequence.After that,the iDAT is used to carry out the dynamic insertion process.This algorithm adopts Sunday jumps algorithm of single pattern matching.With the reasonable increasement of space,it reduces the the average time complexity of the dynamic insertion process in Trie-tree.Practical results show it has good operation performance.","Title: SuperCall: A Secure Interface for Isolated Execution Environment to Dynamically Use External Services.\nYear: 2015\n\nAbstract: Recent years have seen many virtualization-based Isolated Execution Environments (IEE) proposed in the literature to protect a Piece of Application Logic (PAL) against attacks from an untrusted guest kernel. A prerequisite of these IEE system is that the PAL is small and self-contained. Therefore, a PAL is deprived of channels to interact with the external execution environment including the kernel and application libraries. As a result, the PAL can only perform limited tasks such as memory-resident computation with inflexible utilization of system resources. To protect more sophisticated tasks, the application developer has to segment it into numerous PALs satisfying the IEE prerequisite, which inevitably lead to development inefficiency and more erroneous code. In this paper, we propose SuperCall, a new function call interface for a PAL to safely and efficiently call external untrusted code in both the kernel and user spaces. It not only allows flexible interactions between a PAL and untrusted environments, but also improved the utilization of resources, without compromising the security of the PAL. We have implemented SuperCall on top of a tiny hypervisor. To demonstrate and evaluate SuperCall, we use it to build a PAL as part of a password checking program. The experiment results show that SuperCall improves the development efficiency and incurs insignificant performance overhead.","Title: An enhanced particle filtering method for GMTI radar tracking.\nYear: 2016\n\nAbstract: This paper investigates the problem of ground vehicle tracking with ground-moving target indicator (GMTI) radar. In practice, the movement of ground vehicles may involve several different maneuvering types (acceleration, deceleration, standstill, etc.). Consequently, the GMTI radar may lose measurements when the radial velocity of the ground vehicle is below a threshold, i.e., falling into the Doppler blind region. In this paper, to incorporate the information gathered from normal measurements and knowledge on the Doppler blindness constraint, we develop an enhanced particle filtering method for which the importance distributions are inspired by a recent noise-related Doppler blind (NRDB) filtering algorithm for GMTI tracking. Specifically, when constructing the importance distributions, the proposed particle filter takes the advantages of the efficient NRDB algorithm by applying the extended Kalman filter and its generalization for interval-censored measurements. In addition, the linearization and Gaussian approximations in the NRDB algorithm are corrected by the weighting process of the developed filtering method to achieve a more accurate GMTI tracking performance. The simulation results show that the proposed method substantially outperforms the existing methods for the GMTI tracking problem.","Title: New Multiple-Target Tracking Strategy Using Domain Knowledge and Optimization\nYear: 2017\n\nAbstract: This paper proposes an environment-dependent vehicle dynamic modeling approach considering interactions between the noisy control input of a dynamic model and the environment in order to make best use of domain knowledge. Based on this modeling, a new domain knowledge-aided moving horizon estimation (DMHE) method is proposed for ground moving target tracking. The proposed method incorporates different types of domain knowledge in the estimation process considering both environmental physical constraints and interaction behaviors between targets and the environment. Furthermore, in order to deal with a data association ambiguity problem of multiple-target tracking in a cluttered environment, the DMHE is combined with a multiple-hypothesis tracking structure. Numerical simulation results show that the proposed DMHE-based method and its extension could achieve better performance than traditional tracking methods which utilize no domain knowledge or simple physical constraint information only.","Title: Defect detection for patterned fabric images based on GHOG and low-rank decomposition.\nYear: 2017\n\nAbstract: In contrast to defect-free fabric images with macro-homogeneous textures and regular patterns, the fabric images with the defect are characterized by the defect regions that are salient and sparse among the redundant background. Therefore, as an effective tool for separating an image into a redundant part (the background) and sparse part (the defect), the low-rank decomposition model provides an ideal solution for patterned fabric defect detection. In this paper, a novel patterned method for fabric defect detection is proposed based on a novel texture descriptor and the low-rank decomposition model. First, an efficient second-order orientation-aware descriptor, denoted as GHOG, is designed by combining Gabor and histogram of oriented gradient (HOG). In addition, a spatial pooling strategy based on human vision mechanism is utilized to further improve the discrimination ability of the proposed descriptor. The proposed texture descriptor can make the defect-free image blocks lay in a low-rank subspace, while the defective image blocks have deviated from this subspace. Then, a constructed low-rank decomposition model divides the feature matrix generated from all the image blocks into a low-rank part, which represents the defect-free background, and a sparse part, which represents sparse defects. In addition, a non-convex log det as a smooth surrogate function is utilized to improve the efficiency of the constructed low-rank model. Finally, the defects are localized by segmenting the saliency map generated by the sparse matrix. The qualitative results and quantitative evaluation results demonstrate that the proposed method improves the detection accuracy and self-adaptivity comparing with the state-of-the-art methods.","Title: A Fiber-Optic Interferometric Tri-Component Geophone for Ocean Floor Seismic Monitoring.\nYear: 2017\n\nAbstract: For the implementation of an all fiber observation network for submarine seismic monitoring, a tri-component geophone based on Michelson interferometry is proposed and tested. A compliant cylinder-based sensor head is analyzed with finite element method and tested. The operation frequency ranges from 2 Hz to 150 Hz for acceleration detection, employing a phase generated carrier demodulation scheme, with a responsivity above 50 dB re rad/g for the whole frequency range. The transverse suppression ratio is about 30 dB. The system noise at low frequency originated mainly from the 1/f fluctuation, with an average system noise level -123.55 dB re rad/root Hz ranging from 0 Hz to 500 Hz. The minimum detectable acceleration is about 2 ng/root Hz, and the dynamic range is above 116 dB.","Title: Heterogeneous Sparse Relational Data Co-clustering in Social Network\nYear: 2015\n\nAbstract: In social network, users generated multi-typed entities and complex interactive relations. The relational data mining is a hot research in social computing. Co-clustering algorithms have been proposed to mine underlying structure of different entities in heterogeneous social network. However, the real heterogeneous relational data are very sparse. In this paper, we propose a fast High-order Sparse Non-negative Matrix Factorization algorithm to co-cluster heterogeneous sparse relational data based on Correlation Matrix(HSNMF-CM), which is built by the correlation relations of small entities. In HSNMF-CM, the sparseness and size of matrix are reduced simultaneously. Under the sparse constraint, the block coordinate descent algorithms are used to accelerate the convergence rate of the matrix factorization. We assess the performance of the HSNMF-CM on two social data sets. The results show that our algorithm outperforms state-of-the-art algorithms on accuracy and convergence speed, and possesses a high scalability on large-scale heterogeneous relational data sets.","Title: Model for evaluating the E-commerce logistics service quality with hesitant fuzzy uncertain linguistic information.\nYear: 2017\n\nAbstract: In recent years, the electronic information and network technology has developed rapidly, meanwhile, E-commerce has been widely applied in society. Especially the online shopping, relying on its rich products, low price, no time and geographical restrictions and several other distinctive characteristics, which has absorbed attentions of many consumers. In recent years, China's online retail market has seen a big growth. The market share of e-commerce has gradually increased and become a mainstay of China's e-commerce development. However, with the fast growth of e-commerce, consumers' requirements for enterprise service quality is also getting higher and higher. Logistics services is considered to be one of the three main inhibitions of e-commerce and improve logistics service quality has gradually become an important way of e-commerce enterprises to obtain competitive advantage. At present, the research on how to evaluate the quality of e-commerce logistics services has not yet formed a complete and scientific theoretical system and method. In this paper, we have proposed the induced hesitant fuzzy uncertain linguistic Einstein correlated average (IHFULECA) operator. Then, we used the IHFULECA operator to design the multiple attribute decision making problems to estimate the E-commerce logistics service quality. At last, an example is given to shown the effectiveness of the proposed method.","Title: Delay Announcements For Call Centers With Hyperexponential Patience Modeling\nYear: 2017\n\nAbstract: Purpose - The purpose of this paper is to provide delay announcements for call centers with hyperexponential patience modeling. The paper aims to employ a state-dependent Markovian approximation for informing arriving customers about anticipated delay in a real call center.Design/methodology/approach - Motivated by real call center data, the patience distribution is modeled by the hyperexponential distribution and is analyzed by its realistic significance, with and without delay information. Appropriate M/M/s/r + H-2 queueing model is structured, including a voice response system that is employed in practice, and a state-dependent Markovian approximation is applied for computing abandonment. Based on this approximation, a method is proposed for estimating virtual delays, and it is investigated about the problem of announcing virtual delays to customers upon their arrival.Findings - There are two parts of findings from the results obtained from the case study and a numerical study of simulation comparisons. First, using an H-2 distribution for the abandonment distribution is driven by an empirical study which shows its good fit to real-life call center data. Second, simulation experiments indicate that the model and approximation are reasonable, and the state-dependent Markovian approximation works very well for call centers with larger pooling. It is concluded that our approach can be applied in a voice response system of real call centers.Originality/value - Many results pertain to announcing delay information, customer reactions and links to estimating hyperexponential distribution based on real data that have not been established in previous studies; however, this paper analytically characterizes these performance measures for delay announcements.","Title: Robust Adaptive Iterative Learning Control for Discrete-Time Nonlinear Systems With Time-Iteration-Varying Parameters.\nYear: 2017\n\nAbstract: In this paper, the robustness problem in adaptive iterative learning control for discrete-time nonlinear systems with time-iteration-varying parameters is investigated. The time-iteration-varying parameter can be expressed as the sum of an iteration-invariant time-varying part and a bounded iteration-drift term. Then a novel dead-zone method is applied in estimations of the iteration-invariant part and the drift bound simultaneously. The boundedness of tracking error is ensured by rigorous analysis. The efficacy of the proposed method is illustrated through simulation results.","Title: Dynamic Graph Cuts in Parallel.\nYear: 2017\n\nAbstract: This paper aims at bridging the two important trends in efficient graph cuts in the literature, the one is to decompose a graph into several smaller subgraphs to take the advantage of parallel computation, the other is to reuse the solution of the max-flow problem on a residual graph to boost the efficiency on another similar graph. Our proposed parallel dynamic graph cuts algorithm takes the adva...","Title: Study on police graphic plotting technology based on web\nYear: 2017\n\nAbstract: Graphic Plotting based on military use has been a hot issue in the aspect of real-time situation research. It plays a very important role in various military fields like operation command. In civil fields, especially in the public security industry, applications based on Police Graphic Symbol Standards starts late but progresses fast. With the maturing of its application in public secrity field, Graphic Plotting for Police needs to be further improved. This paper presents a way to express and transmit Police Graphic Plotting data with SVG technology, designs and develops a Police Graphic Symbol authoring tool and Graphic Symbol publishing software. The software has been verified to be a good solution to Graphic Plotting in public security field.","Title: Exponential Synchronization for Second-Order Nodes in Complex Dynamical Network with Communication Time Delays and Switching Topologies\nYear: 2017\n\nAbstract: This paper is devoted to the study of exponential synchronization problem for second-order nodes in dynamical network with time-varying communication delays and switching communication topologies. Firstly, a decomposition approach is employed to incorporate the nodes¿ inertial effects into the distributed control design. Secondly, the sufficient conditions are provided to guarantee the exponential synchronization of second-order nodes in the case that the information transmission is delayed and the communication topology is balanced and arbitrarily switched. Finally, to demonstrate the effectiveness of the proposed theoretical results, it is applied to the typical second-order nodes in dynamical network, as a case study. Simulation results indicate that the proposed method has a high performance in synchronization of such network.","Title: Cross Domain Collaborative Filtering by Integrating User Latent Vectors of Auxiliary Domains.\nYear: 2017\n\nAbstract: Cross-Domain Collaborative Filtering solves the sparsity problem by transferring rating knowledge across multiple domains. However, how to transfer knowledge from auxiliary domains is nontrivial. In this paper, we propose a model-based CDCF algorithm by Integrating User Latent Vectors of auxiliary domains (CDCFIULV) from the perspective of classification. For a user-item interaction in the target domain, we first use the trivial location information as the feature vector, and use the rating information as the label. Thus we can convert the recommendation problem into a classification problem. However, such a two-dimensional feature vector is not sufficient to discriminate the different rating classes. Hence, we require some other features for the classification problem with the help of the rating information from the auxiliary domains. In this paper, we assume the auxiliary domains contain dense rating data and share the same aligned users with the target domain. In this scenario, we employ UV decomposition model to obtain the user latent vectors from the auxiliary domains. We expand the trivial location feature vector in the target domain with the obtained user latent vectors from all the auxiliary domains. Thus we can effectively add features for the classification problem. Finally, we can train a classifier for this classification problem and predict the missing ratings for the recommender system. Hence the hidden knowledge in the auxiliary domains can be transferred to the target domain effectively via the user latent vectors. A major advantage of the CDCFIULV model over previous collective matrix factorization or tensor factorization models is that our model can adaptively select significant features during the training process. However, the previous collective matrix factorization or tensor factorization models need to adjust the weights of the auxiliary domains according to the similarities between the auxiliary domains and the target domain. We conduct extensive experiments to show that the proposed algorithm is more effective than many state-of-the-art single domain and cross domain CF methods.","Title: Modelling and Analysis of the Cerebrospinal Fluid Flow in the Spinal Cord.\nYear: 2017\n\nAbstract: The cerebrospinal fluid (CSF) flow in the spinal cord is important in maintaining the stability of the central nervous system. However, the interaction between CSF and spinal cord is not well understood. A three-dimensional (3D) simplified finite element model (FEM) of a sheep CSF and spinal cord segment was developed, verified using clinical experimental data, and used to investigate the effect of deformations and stress distributions on spinal cord in normal physiological conditions. The commercial software ANSYS Workbench was adopted to simulate the unidirectional CSF flow along the coaxial tube, which considered the bi-directional fluid-solid coupling. It was demonstrated that CSF had a slight impact on the spinal cord, which was transmitted to the white and gray matter through the pia mater. The pia mater protected the normal physiological function of the white and gray matter while the spinal dura mater ensured the regular rate and pressure of CSF. It was also showed that the CSF flow in the spinal cord was laminar. This model might help us to better understand the mechanism of interaction between CSF and spinal cord and provide a baseline for mechanical comparisons in spinal cord injury.","Title: Computer vision based fall detection by a convolutional neural network.\nYear: 2017\n\nAbstract: In this work, we propose a novel computer vision based fall detection system, which could be applied for the health-care of the elderly people community. For a recorded video stream, background subtraction is firstly applied to extract the human body silhouette. Extracted silhouettes corresponding to daily activities are applied to construct a convolutional neural network, which is applied for classification of different classes of human postures (e.g., bend, stand, lie and sit) and detection of a fall event (i.e., lying posture is detected in the floor region). As far as we know, this work is the first attempt for the application of the convolutional neural network for the fall detection application. From a dataset of daily activities recorded from multiple people, we show that the proposed method both achieves higher postures classification results than the state-of-the-art classifiers and can successfully detect the fall event with a low false alarm rate.","Title: The optimization solutions method for customs risk with random dispatched model.\nYear: 2017\n\nAbstract: In a market economy, it isn't an effective solution to the main contradiction of the Customs if simply relying on unlimited investment of management resources and the extensive extension of expansion-style management. Based on the need of solving this principal contradiction, the paper comprehensively reviews the concept and status of risk dispatched. We constructed a customs risk decision and performance evaluation of risk parameters management theoretical models. Also, we analyze the problems of customs risk management both from qualitative and quantitative aspects and make recommendations for the further optimization of risk management and surveillance.","Title: A new self-tuning fuzzy controller for vibration of a flexible structure subjected to multi-frequency excitations.\nYear: 2017\n\nAbstract: This work proposes a new self-tuning fuzzy controller for vibration control of a flexible structure subjected to both single-frequency and multi-frequency excitations. A piezoelectric stack actuator is used to generate control force to attenuate vibrations in the resonant and non-resonant frequency ranges. As a first step, modal frequencies and modal shapes of the flexible beam structure are obtained via the finite element method, and these are verified through comparison with the measured values. Second, in order to attenuate multi-frequency vibration of the beam, a new fuzzy controller with self-tuning factors is proposed. This controller is independent of the structure model and very adaptive to variable excitations. Then, vibration control performances of the self-tuning fuzzy controller are experimentally investigated under two different excitation conditions: single-frequency and multi-frequency excitations. It is shown that vibration control capability of the proposed controller outperforms conventional fuzzy controller under two different excitation conditions. In addition, it is demonstrated by experimentally implementing the proposed self-tuning fuzzy controller that high performances of multi-frequency vibration control are successfully achieved in which both amplitude and frequency of sinusoidal excitations are varied.","Title: Wii: Device-Free Passive Identity Identification via WiFi Signals.\nYear: 2017\n\nAbstract: Human behavior data is the basis of behavior analysis, and usually we need to collect large quantities of data before analysis. Most existing data collection methods are labor intensive works in which the volunteers need to be asked to behave naturally under the monitoring of researchers. Identity identification can be used in passive data collection of human behavior analysis systems in big data. Previous researches show the sensing potential of WiFi signals in a device-free passive manner. It is confirmed that human's gait is unique from each other like fingerprint and iris. As a result, researchers start to explore the ability of WiFi in human identification. However, the identification accuracy of existing approaches is not satisfactory in practice. In this paper, we present Wii, a device-free WiFi-based Identity Identification approach utilizing human's gait based on Channel State Information (CSI) of WiFi signals. Principle Component Analysis (PCA) and low pass filter are applied to remove the noises in the signals. We then extract entities' gait features from both time and frequency domain. Based on these features, Wii realizes identity identification through a Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel. It is implemented using commercial WiFi devices and evaluated in a typical indoor scenario. The results indicate that Wii achieves high identification accuracy with low computational cost and has the potential to work in human behavior analysis systems.","Title: Impact of Emissions Trading System on Renewable Energy Output.\nYear: 2017\n\nAbstract: In this paper, a cross-national panel is used to assess the impact of emissions trading system (ETS) on renewable energy output with a difference-in-difference design. From 2002 to 2013, several countries adopted ETS as a primary vehicle to drive carbon pollution reduction and boost the growth of renewables. By exploiting the cross-nation and cross-time variation in the timing of ETS, we find that ETS has materially improved renewable energy output, thereby indicating that the growth of the renewables has been successfully boosted through ETS. In addition, we examine the dynamics of the relationship between ETS and renewable energy output. Estimation result shows the ETS establishment has a trend effect on renewable energy output.","Title: An Iteration-Varying Dead-Zone Based Robust Adaptive Ilc For Discrete-Time Nonlinear Systems With Uncertainties\nYear: 2017\n\nAbstract: In this paper, we investigate the robust adaptive iterative learning control issue for discrete-time nonlinear systems with uncertainties by using an iteration-varying dead-zone approach. The uncertainties are dependent on both time index and iteration index, which can be expressed as the sum of a time-varying but iteration-invariant part and a bounded iteration-drift term. Then, a novel iteration-varying dead-zone approach is employed in the estimations of the iteration-invariant part and the drift bound simultaneously. The ultimate error bound is given explicitly with rigorous proof. Finally, simulation result has illustrated the efficacy of the proposed approach.","Title: Adaptation and contextualization of deep neural network models.\nYear: 2017\n\nAbstract: The ability of Deep Neural Networks (DNNs) to provide very high accuracy in classification and recognition problems makes them the major tool for developments in such problems. It is, however, known that DNNs are currently used in a ‘black box’ manner, lacking transparency and interpretability of their decision-making process. Moreover, DNNs should use prior information on data classes, or object categories, so as to provide efficient classification of new data, or objects, without forgetting their previous knowledge. In this paper, we propose a novel class of systems that are able to adapt and contextualize the structure of trained DNNs, providing ways for handling the above-mentioned problems. A hierarchical and distributed system memory is generated and used for this purpose. The main memory is composed of the trained DNN architecture for classification/prediction, i.e., its structure and weights, as well as of an extracted — equivalent — Clustered Representation Set (CRS) generated by the DNN during training at its final — before the output — hidden layer. The latter includes centroids — ‘points of attraction’ — which link the extracted representation to a specific area in the existing system memory. Drift detection, occurring, for example, in personalized data analysis, can be accomplished by comparing the distances of new data from the centroids, taking into account the intra-cluster distances. Moreover, using the generated CRS, the system is able to contextualize its decision-making process, when new data become available. A new public medical database on Parkinsonu0027s disease is used as testbed to illustrate the capabilities of the proposed architecture.","Title: Method for Determining the Resonance Frequency of a Fiber Optic Interferometric Accelerometer.\nYear: 2018\n\nAbstract: A novel measurement method for the resonance frequency of a fiber optic interferometric accelerometer, one of the most important technical parameters for such a sensor, is proposed and demonstrated. First, a variable phase shift is induced by a piezoelectric fiber stretcher which also serves to ascertain that the modulation depth is unchanged while maintaining the drive amplitude and increasing th...","Title: Hierarchical control for parallel bidirectional power converters of a grid-connected DC microgrid.\nYear: 2017\n\nAbstract: The DC microgrid is connected to the AC utility by parallel bidirectional power converters (BPCs) to import/export large power, whose control directly affects the performance of the grid-connected DC microgrid. Much work has focused on the hierarchical control of the DC, AC, and hybrid microgrids, but little has considered the hierarchical control of multiple parallel BPCs that directly connect the DC microgrid to the AC utility. In this paper, we propose a hierarchical control for parallel BPCs of a grid-connected DC microgrid. To suppress the potential zero-sequence circulating current in the AC side among the parallel BPCs and realize feedback linearization of the voltage control, a d-q-0 control scheme instead of a conventional d-q control scheme is proposed in the inner current loop, and the square of the DC voltage is adopted in the inner voltage loop. DC side droop control is applied to realize DC current sharing among multiple BPCs at the primary control level, and this induces DC bus voltage deviation. The quantified relationship between the current sharing error and DC voltage deviation is derived, indicating that there is a trade-off between the DC voltage deviation and current sharing error. To eliminate the current sharing error and DC voltage deviation simultaneously, slope-adjusting and voltage-shifting approaches are adopted at the secondary control level. The proposed tertiary control realizes precise active and reactive power exchange through parallel BPCs for economical operation. The proposed hierarchical control is applied for parallel BPCs of a grid-connected DC microgrid and can operate coordinately with the control for controllable/uncontrollable distributional generation. The effectiveness of the proposed control method is verified by corresponding simulation tests based on Matlab/Simulink, and the performance of the hierarchical control is evaluated for practical applications.","Title: Discovering new PI3Kα inhibitors with a strategy of combining ligand-based and structure-based virtual screening.\nYear: 2018\n\nAbstract: PI3Kα is a promising drug target for cancer chemotherapy. In this paper, we report a strategy of combing ligand-based and structure-based virtual screening to identify new PI3Kα inhibitors. First, naïve Bayesian (NB) learning models and a 3D-QSAR pharmacophore model were built based upon known PI3Kα inhibitors. Then, the SPECS library was screened by the best NB model. This resulted in virtual hits, which were validated by matching the structures against the pharmacophore models. The pharmacophore matched hits were then docked into PI3Kα crystal structures to form ligand-receptor complexes, which are further validated by the Glide-XP program to result in structural validated hits. The structural validated hits were examined by PI3Kα inhibitory assay. With this screening protocol, ten PI3Kα inhibitors with new scaffolds were discovered with IC values ranging 0.44-31.25 μM. The binding affinities for the most active compounds 33 and 74 were estimated through molecular dynamics simulations and MM-PBSA analyses.","Title: Information Propagation Prediction Based on Key Users Authentication in Microblogging.\nYear: 2018\n\nAbstract: In microblogging, key users are a significant factor for information propagation. Key users can affect information propagation size while retweeting the information. In this paper, to predict information propagation, we propose a novel linear model based on key users authentication. This model mines key users to dynamically improve the linear model while predicting information propagation. So our model can not only predict information propagation but also mine key users. Experimental results show that our model can achieve remarkable efficiency on predicting information propagation problem in real microblogging networks. At the same time, our model can find the key users who affect information propagation.","Title: A Decentralized Coordination Control Method for Parallel Bidirectional Power Converters in a Hybrid AC-DC Microgrid.\nYear: 2018\n\nAbstract: In the hybrid ac-dc microgrid, the ac and dc subgrids are connected by bidirectional power converters (BPCs) that play an important role in the load power sharing and power interaction between the ac and dc subgrids. The coordination control and circulating current suppression for the parallel BPC system are very challenging. In this paper, a decentralized coordination control method is proposed f...","Title: Discrete-Time Switching Periodic Adaptive Control For Time-Varying Parameters With Unknown Periodicity\nYear: 2018\n\nAbstract: In this paper, we address the problem of unknown periodicity for a class of discrete-time nonlinear parametric systems without assuming any growth conditions on the nonlinearities. The unknown periodicity hides in the parametric uncertainties, which is difficult to estimate with existing techniques. By incorporating a logic-based switching mechanism, we identify the period and bound of unknown parameter simultaneously. Lyapunov-based analysis is given to demonstrate that a finite number of switchings can guarantee the asymptotic tracking for the nonlinear parametric systems. The simulation result also shows the efficacy of the proposed switching periodic adaptive control approach.","Title: A Novel Camera Based Approach For Automatic Expiry Date Detection And Recognition On Food Packages\nYear: 2018\n\nAbstract: There is abundant of information on food packages, which include the food name, the expiry date and the ingredients. These information, especially the expiry date needs to be coded correctly before the products can be released into the market/supply chains. Failure of printing the correct expiry date can lead to both the health issues to the public and financial issues for recalling product back and even reimbursement. In this paper, we develop an automatic system that can achieve the expiry date region detection and recognition in an efficient and effective way. A deep neural network (DNN) based approach is firstly applied to find the expiry date region on the food package. The date characters are then extracted and recognized through the image processing and machine learning methods from the expiry date region. The system is the first camera based automatic system for recognizing expiry date on food packages. And the results tested on different types of food packages show that the system can achieve good performance on both detection and recognition of the expiry date.","Title: Mathematical Performance Evaluation Model for Mobile Network Firewall Based on Queuing.\nYear: 2018\n\nAbstract: While mobile networks provide many opportunities for people, they face security problems huge enough that a firewall is essential. The firewall in mobile networks offers a secure intranet through which all traffic is handled and processed. Furthermore, due to the limited resources in mobile networks, the firewall execution can impact the quality of communication between the intranet and the Internet. In this paper, a performance evaluation mathematical model for firewall system of mobile networks is developed using queuing theory for a multihierarchy firewall with multiple concurrent services. In addition, the throughput and the package loss rate are employed as performance evaluation indicators, and discrete-event simulated experiments are conducted for further verification. Lastly, experimental results are compared to theoretically obtained values to identify a resource allocation scheme that provides optimal firewall performance and can offer a better quality of service (QoS) in mobile networks.","Title: PWiG: A Phase-based Wireless Gesture Recognition System\nYear: 2018\n\nAbstract: With the development of the artificial intelligence, people hope that the advancement of the science and technology will continuously bring more convenience to their daily life. Therefore, gesture recognition has drawn more attentions. In the previous research, people paid their attentions on the aspect of the wearable devices and computer graphic. Although the recognition accuracy of previous methods is satisfactory under line-of-sight, the costs are very high and they require the users to be equipped with wearable sensors, which hinder their wide deployment. The development of wireless network provides convenience for solving this problem. Different gestures can be identified only according to the fluctuation of RSSI of wireless signals. But the intrinsic limitations of RSSI make it difficult to be feasible. Fortunately, CSI-based gesture recognition systems overcome the shortcomings above. In this paper, we propose a Phase-based Wireless Gesture recognition system PWiG, an accurate device-free gesture recognition approach. Compared with other existing gesture recognition systems, PWiG only needs commercial Wi-Fi devices to identify different gestures. PWiG uses the more sensitive phase information. Moreover, it reduces the hardware cost and greatly simplifies the process of the gesture extraction only by calculating the variance values. In addition, PWiG meets the standard of gesture recognition. According to the experimental results, PWiG achieves an average recognition accuracy of 94% in line-of-sight scenario and 89% in none-line-of-sight scenario.","Title: Robust WLAN-Based Indoor Intrusion Detection Using PHY Layer Information.\nYear: 2018\n\nAbstract: Intrusion detection techniques are widely used to guarantee the security of people's possessions. With the rapid development of wireless communication, device-free passive human detection based on wireless techniques may have more opportunities in intrusion detection. WiFi has been widely deployed in both public and private areas, which can be used as generalized sensors to detect human motion beyond communication. As a result, there have been several researches on WLAN-based motion detection. However, the detection accuracy of previous approaches declines significantly when people's moving speed becomes very slow. In this paper, we explore a novel method which has a relative stable detection performance under different moving speeds. We extract a novel feature representing the fluctuation of the whole channel from channel state information at the physical layer of 802.11n wireless networks, and utilize a probability technique to detect human motion. A hidden Markov model is leveraged as the classifier to make human detection a probability problem. We implement the system using off-the-shelf WiFi devices and evaluate it in two scenarios. As indicated in the evaluation results, our approach is an appropriate method for intrusion detection.","Title: Fabric Defect Detection Based on Biological Vision Modeling.\nYear: 2018\n\nAbstract: Fabric defect detection plays a key role in the quality control of textiles. Existing fabric defect detection methods adopt traditional pattern recognition methods; however, these methods lack adaptability and present poor detection performance. Because biological vision system has the ability to quickly locate salient objects, we propose a novel fabric defect detection algorithm based on biological vision modeling by simulating the mechanism of biological visual perception. First, a distinct, efficient, and robust feature descriptor from the biological modeling of P ganglion cells, which was proposed in our previous work, is adopted to improve the representation of fabric images with complex textures. To account for the low-rank and sparsity characteristics of biological vision, the low-rank representation (LRR) technique is adopted to model biological visual saliency, and it can decompose the fabric image into backgrounds and salient defect objects. Meanwhile, dictionary learning and Laplacian regularization are integrated into the LRR model as follows: 1) dictionary learning is used to denoise the saliency map; and 2) Laplacian regularization enlarges the gaps between defective regions and the background. Finally, the linearized accelerated direction method with adaptive penalty is adopted to solve the proposed model. The experimental results emphasize that the proposed algorithm has good detection performance for plain or twill fabrics with simple textures as well as for patterned fabrics with complex textures. Moreover, the proposed method is superior to the state-of-the-art methods in terms of its adaptability and detection efficiency.","Title: Multiple Model Ballistic Missile Tracking With State-Dependent Transitions and Gaussian Particle Filtering.\nYear: 2018\n\nAbstract: This paper proposes a new method for tracking the entire trajectory of a ballistic missile from launch to impact on the ground. Multiple state models are used to represent the different ballistic missile dynamics in three flight phases: boost, coast, and re-entry. In particular, the transition probabilities between state models are represented in a state-dependent way by utilizing domain knowledge...","Title: Algorithm of Fuzzy Support Vector Machine based on a Piecewise Linear Fuzzy Weight Method\nYear: 2018\n\nAbstract: AbstractThis article describes how fuzzy support vector machines FSVMs function well with good anti-noise performance, which receives the attention of many experts. However, the traditional center-distance fuzzy weight assignment method assigns support vectors with a small value of a membership degree and this weakens the role of support vectors in classification. In this article, a piecewise linear fuzzy weight computing method is proposed, in which boundary samples are assigned with a larger value of membership degree and samples far from the mean vector are assigned a smaller value of membership degree. The proposed method has a good classification performance, because the influence of noise samples is weakened and meanwhile the support vectors are paid much more attention. The experiments on the UCI database and MNIST data set fully verify the effectiveness of the proposed algorithm.","Title: Research on the Complexity and Chaos Control about a Closed-Loop Supply Chain with Dual-Channel Recycling and Uncertain Consumer Perception.\nYear: 2018\n\nAbstract: According to game theory, chaotic dynamics theory, and complexity based on the literature review about the pricing strategy and recycling channels of the closed-loop supply chain, on the background of the widespread hybrid recycling channels in Chinese electronic products market, this paper builds a closed-loop supply chain model with dual-channel recycling composed of one manufacturer and one third-party. We assume that the consumer perception towards the remanufacturing products is uncertain and limited. We carry on theoretical analysis of this model and perform numerical simulations from the perspective of entropy theory. Results show that a precipitous speed of recycling price adjustment of the manufacturer or the third-party will both lead the system into a chaotic state and cause the entropy of the system to increase. The system is sensitive to initial conditions in this chaotic condition. Focusing on the harmful effects of chaotic system, we introduce adjustment parameter to efficiently control the chaos. The results have a strong reference value to practical problems, so it has a great value in both theory and application.","Title: Single-cell-trapping Microarrays with High Trapping Efficiency and Negligible Shear Stress\nYear: 2018\n\nAbstract: In this study, two novel hydrodynamics-based radial microarrays are proposed to trap single cells with high trapping efficiency and negligible shear stress. Both microarrays are designed based on a single cell trapping microdevice we designed using a combination of the stagnation point flow and the boundary effect. For each microarray, the efficiency of trapping is evaluated with the flow velocity distribution in the microfluidic channel through two models: an initial model calculates the velocity distribution without cell trapping; in the contrary, a trapping model estimates the velocity distribution when a cell is trapped at the stagnation point. In both models, the flow velocity distribution is obtained using the computational fluid dynamics (CFD) package ANSYS 16.0. We conclude that both microarrays can capture single cells with high trapping success rate and negligible shear stress, which would be effective experimental platforms to study single cell behaviors in response to extracellular stimuli.","Title: A Radial Microfluidic Array For Studying Single-Cell Ca2+ Dynamics Stimulated By Dynamic Atp Signals\nYear: 2018\n\nAbstract: A radial microfluidic array is proposed to analyze intracellular calcium dynamics in response to dynamic extra-cellular adenosine triphosphate (ATP) stimulation at single cell level. The microfluidic array consists of multiple single cell trapping units in radial distribution with same angle, each unit is designed by a combination of stagnation point flow and physical barrier. Cellular experimental results verified that the effectiveness of the single cell trapping and intracellular calcium dynamic behaviors in response to static or dynamic extra-cellular ATP stimulation.","Title: Bat-inspired hair sensor.\nYear: 2016\n\nAbstract: We present the design of a directional airflow sensor inspired by the bat hair sensory system. The design is based on the integration of a MEMS structure with mechanical amplification of a deflecting hair on a suspended membrane together with differential sensing of parallel plate capacitors placed at the base of the hair. We describe the design and show simulations predicting that the structure is capable of detecting airspeeds of 0.5 m/sec in a directionally sensitive fashion. Furthermore, the structure is mechanically simple and inexpensive to fabricate. It has been integrated into a miniature form factor for deployment on the wing of a freely flying bat, and MEMS fabrication is currently underway.","Title: Factors Affecting ENF Capture in Audio.\nYear: 2019\n\nAbstract: The electric network frequency (ENF) signal is an environmental signature that can be captured in audiovisual recordings made in locations where there is electrical activity. This signal is influenced by the power grid in which the recording is made, and recent work has shown that it can be useful toward a number of forensics and security applications. An under-studied area of ENF research is the ...","Title: Composite Energy Function-Based Spatial Iterative Learning Control in Motion Systems.\nYear: 2018\n\nAbstract: In this brief, a novel spatial iterative learning control (ILC) method is proposed for a class of high-order nonlinear motion systems in the presence of both parametric and nonparametric uncertainties. Since the system performs the tracking task iteratively in the spatial domain and the uncertainties are functions of spatial coordinates, the traditional ILC that updates the control signals in the ...","Title: Logistics Terminal Distribution Mode and Path Optimization Based on Ant Colony Algorithm.\nYear: 2018\n\nAbstract: In order to discuss the logistics distribution that directly affects the satisfaction of consumers for the entire online shopping activities, this article mainly studies the logistics terminal distribution mode and path optimization, and combined with the application of ant colony algorithm in the traveling salesman problem, analyses the basic principle and implementation process of ant colony algorithm. In addition, through reference to map and field research, we consider the route length and road conditions (slope and congestion) of the the regional distribution point, and collect and draw the geographic information surrounding area A. Moreover, some key parameters in ant colony algorithm in value are chosen, and with the collected information as a concrete example, MATLAB simulation is carried out for the logistics terminal distribution path optimization based on ant colony algorithm, and its scientific nature and feasibility are verified. The simulation results showed that the ant colony algorithm has good feasibility so that it can be widely applied. As a result, it is concluded that the application of ant colony algorithm has great significance in the exploration of the logistics terminal distribution path optimization.","Title: Decentralized Coordination Control For Parallel Bidirectional Power Converters In A Grid-Connected Dc Microgrid\nYear: 2018\n\nAbstract: In the grid-connected mode, the dc microgrid is connected to the utility by parallel bidirectional power converters (BPCs), which provide voltage support for the dc microgrid. The coordination control for these parallel BPCs is very challenging. First, for the parallel BPCs, there is circulating current among them, which limits the total system capacity and may damage switching devices. Second, taking the constant power load into consideration, the performance especially the stability of the dc microgrid is degraded if the conventional i(dc)-v(dc) droop is adopted to share the power. Third, the voltage restoration should be faster for the better quality of dc voltage, and the restoration strategy should be scalable to the changes of the de microgrid topology for the better flexibility. For these problems, this paper proposes a decentralized control method for the parallel BPCs, which can make the BPCs operate in coordination and provide voltage support for the de microgrid well. Furthermore, the reliability of the proposed control method is illustrated by the stability analysis. All the conclusions are verified by the real-time hardware-in-loop tests.","Title: Management of expressway service area based on integrated optimization.\nYear: 2018\n\nAbstract: In view of the imperfect construction and the widespread loss on domestic expressway service areas, simply relying on the capital and human resources investment cannot improve the economic benefits efficiently. The M-Expressway service area is one of the most representative service areas in the Shanghai-Nanjing region. In this optimization project, we optimized the main revenue item and allocated parking spaces based on profit contributions, finally optimized the parking layout. With profit as the core, we linked the scattered business in the service area and achieved the goal of sequential optimization and overall optimization.","Title: Comparison of advantages and disadvantages among various algorithms in logistics path design - Taking H-group as an example.\nYear: 2018\n\nAbstract: There are many kinds of VRP problems and there are many ways to solve them. In this paper, we use ant colony algorithm, genetic algorithm, and annealing algorithm to optimize the selection of the logistics path of H-group located at He Nan Province. It establishes an algorithm evaluation system, and analyzes the performance of the three algorithms in six dimensions from qualitative and quantitative perspectives. Through MATLAB data calculation, we found that the ant colony algorithm performs equally well on the solution quality, solution efficiency, code storage, robustness, adaptability, and optimality.","Title: KeggExp: a web server for visual integration of KEGG pathways and expression profile data.\nYear: 2019\n\nAbstract: Effective visualization is important for knowledge discovery when analysing expression profile data. However, existing tools for visually integrating expression profile data with KEGG pathway maps lack extensive interactive visualization operations. KeggExp simultaneously presents the pathway map of one pathway, dendrogram and heatmap of the genes in the pathway and scatter map of one gene; and also provides interactive operations for highlighting specific genes on the pathway map, including differentially-expressed genes, co-expressed genes selected from the heatmap and user-input genes. With KeggExp, researchers, including those without programming skills, can take advantage of its interactive operations to determine key genes or pathways when analysing expression profile data. Availability and implementation: Freely available at http://www.fgvis.com/expressvis/KeggExp/. Language: JavaScript, python; Libraries: D3.js, Rxjs, Angular, Django, Django rest frame work, Scipy.","Title: Spindle-Net: Cnns For Monocular Depth Inference With Dilation Kernel Method\nYear: 2018\n\nAbstract: Learning depth from a single image is an important issue in computer vision. To solve this problem, encoder-decoder architect is usually employed as a powerful architecture to learn the dense corresponding function. In this work, we propose a symmetrical Spindle network of the encoder-decoder to learn the fine-grained depth. Unlike traditional convolution neural network, we first boost up the feature maps from low-dimension space to a high-dimension space, then extract the features for monocular depth learning. In order to overcome limitation of the computer memory, a single image super-resolution technique is proposed to replace the boosting process by fusing local cues in edge direction. Given the super-resolution images, the monocular depth learning needs more global information than most architectures for pixel-wise predictions. To address this issue, dilation kernel method is proposed to enlarge the receptive field in each layer. For the task of the super-resolution, the proposed method achieves better performance than the state-of-the-art methods. Extensive experiments on the monocular depth inference demonstrate that the Spindle network could achieve comparable performance on the NYU and Make3D datasets, compared with the state-of-the-art algorithms. The proposed method reveals a new perspective to learn the depth from a single image, which shows a promising generality to other pixel-wise prediction problems.","Title: Global-optimization-based model decomposition for support-free multi-DOF 3D printing.\nYear: 2018\n\nAbstract: In 3D printing, using supporting materials as few as possible is critical for efficiency and material saving. Although both model partition methods and 3D printers with multi-DOF(degree of freedom) have been developed independently to tackle the problem, only a few existing approaches combined partition methods with multi-DOF printers. We present a global-optimization-based model decomposition method for multi-DOF 3D printers to achieve consistent printing with the least supporting materials. We solve the minimization of the surface area that need supporting where the printing sequence is determined inherently by global single-objective optimization. We first describe the printing constraints for using a multi-DOF 3D printer, then propose an optimization framework that meets the constraints. Experiments show the merits of our method.","Title: An approximation algorithm for vehicle routing with compatibility constraints.\nYear: 2018\n\nAbstract: We study a multiple-vehicle routing problem with a minimum makespan objective and compatibility constraints. We provide an approximation algorithm and a nearly-matching hardness of approximation result. We also provide computational results on benchmark instances with diverse sizes showing that the proposed algorithm (i) has a good empirical approximation factor, (ii) runs in a short amount of time and (iii) produces solutions comparable to the best feasible solutions found by a direct integer program formulation.","Title: ADRC-based Longitudinal Control for Novel Flight Vehicle with Moving Mass\nYear: 2018\n\nAbstract: An adaptive longitudinal control law for moving mass control of a novel flight vehicle configuration is proposed. The coupling dynamic model between angle of attack and deflection of moving mass is generated. The dynamic analysis indicates that the proposed moving mass configuration with larger mass ratio gives rise to more dynamic coupling and maneuverability. Moreover, the control authority is determined by the mass ratio of the moving mass and the difference between the mass center of the moving mass and the mass center of the vehicle body. To deal with the coupling caused by the additional inertia moment of moving mass, the coupling dynamics system is transformed into a cascade system for controller design. Active disturbance rejection control framework is employed to design the adaptive longitudinal controller. Its extended state observer estimates the total disturbance to overcome the uncertainties in the flight vehicle model. The simulation results show that the proposed configuration is feasible and validate the quality of the adaptive controller which ensures good performance.","Title: Design of Remote Fitting Platform Based on Virtual Clothing Sales\nYear: 2022\n\nAbstract: To improve the convenience and effect of fitting process, an online fitting system of user-personalized body type based on the virtual technology is put forward. Firstly, it develops the fitting system with Java as the development language and constructs the human model, spinning motion model, and virtual clothing model; then, it divides the relevant model creation based on the body, generates the personalized body type, and designs the slab model, represented by triangular patch, while all points in same gender model keep the spatial position relation with each other to simplify the interpolation process; finally, it verifies the efficiency of the developed system through the factor analysis and cluster fitting design.","Title: Characterization of Nucleobases in Broadband Terahertz Spectra from 0.5 to 10 THz with the Air-Biased-Coherent-Detection Technique.\nYear: 2019\n\nAbstract: Terahertz time-domain spectroscopy (THz-TDS) is an effective coherent detection technique for deeply understanding the structures and functions of biomolecules. However, generally not full information in the whole THz range can be obtained due to the limited detection bandwidth (usually less than 5 THz) of the traditional THz-TDS systems. In this paper, effective THz absorption spectra in 0.5-10 THz range of five typical nucleobases of DNA/RNA are characterized with a super broadband THz detection technique, called the air-biased- coherent-detection (THz-ABCD) technique. Few unexpected characteristic absorption peaks appeared in the low-frequency region and meanwhile a series of anticipated characteristic absorption peaks are found in the high-frequency region. The fingerprint spectra of these nucleobases are helpful for further analysis on the vibration and twisting behavior of hydrogen bonds, van der Waals and electrostatic forces etc. between and within DNA/RNA biomolecules.","Title: Aging, Urbanization, and Energy Intensity based on Cross-national Panel Data.\nYear: 2017\n\nAbstract: On the basis of an unbalanced cross-national panel, this study employs the two-way fix-effects model to investigate the impact and effects of aging and urbanization on energy intensity. Estimation results show that aging has a negative effect on energy intensity, whereas urbanization has a positive effect on energy intensity. Empirical results also show that GDP per capita, overall productivity, and energy price have significant negative impacts on energy intensity. In addition, we find no empirical evidence of the general influence of foreign direct investment (FDI) on energy intensity. In the comparison of the classification of developed and developing countries, we further validate the previous results. Thus, this study provides a reference for governments in reducing energy intensity and improving governance.","Title: Research on the system of smart city park based on cloud computing\nYear: 2019\n\nAbstract: In order to effectively improve the management level and service level of the intelligent park, the information fusion in the intelligent park is studied. First, the main concepts of the Internet of things and cloud computing are discussed. It includes key technology, architecture, application field and key technology of cloud computing, platform architecture and so on. Based on the above, a hardware architecture and technical scheme based on cloud computing, cloud storage and cloud analysis is proposed. The design of the application system, the application support platform, the transmission and the sensors used in the park are discussed. In addition, a software architecture and technical scheme for information intelligent application system based on cloud computing, cloud storage and cloud analysis is proposed. The research target and function design of each application system are studied in detail. Finally, the implementation effect of intercommunication and fusion processing between the systems is analyzed. The results show that the system can effectively solve the information island phenomenon. The introduction of new technology will bring great social and economic benefits for the park. It provides a reference for the development of intelligent cities.","Title: Research on intelligent city energy management based on Internet of things\nYear: 2019\n\nAbstract: In order to solve the problem of energy management in Intelligent City, the energy management platform of the Internet of things is applied. the method of the energy consumption measurement data access to the energy management platform of the Internet of things is studied. According to the different communication protocols used by the energy management subsystem, the access methods of OPC technology, Web Service and open database connectivity and front-end communication are discussed. The results show that the intelligent city energy management system based on the Internet of things can meet the needs of the “intelligent city” construction. The system integrates the isolated energy information and realizes the energy consumption measurement. It lays the foundation for the diagnosis and energy saving evaluation of urban energy consumption.","Title: Fluid models for call centers with delay announcement and retrials.\nYear: 2018\n\nAbstract: This paper models a call center as a multi-server queue where anticipated delays are announced to customers upon arrival, and customer balking, reneging and retrials are modeled explicitly. The resulting queue with delay announcement is modeled in a stationary setting. We propose a fluid approximation to estimate the possibility of announcing the mean delay distribution and the retrials in the system. This approximation method can overcome some of the computational issues involved with a continuous time Markov chain analysis. The fluid approximation is also validated that it can work well in overloaded systems by performing a comparison between the fluid model and the stochastic model with delay information, and by performing the other comparison between the fluid model and the simulation model. Through a numerical study, this paper demonstrates the significance of delay information in a call center with retrials. In particular, delay announcement is more important in the system with a high retrial probability. Thus, we show how a delay announcement greatly reduces customer reneging and thereby improves customer satisfaction. It is shown that disregarding retrials in call centers with delay information may result in large distortions in the management of call centers.","Title: An End-To-End Deep Neural Architecture For Optical Character Verification And Recognition In Retail Food Packaging\nYear: 2018\n\nAbstract: There exist various types of information in retail food packages, including food product name, ingredients list and use by date. The correct recognition and coding of use by dates is especially critical in ensuring proper distribution of the product to the market and eliminating potential health risks caused by erroneous mislabelling. The latter can have a major negative effect on the health of consumers and consequently raise legal issues for suppliers. In this work, an end-to-end architecture, composed of a dual deep neural network based system is proposed for automatic recognition of use by dates in food package photos. The system includes: a Global level convolutional neural network (CNN) for high-level food package image quality evaluation (blurry/clear/missing use by date statistics); a Local level fully convolutional network (FCN) for use by date ROI localisation. Post ROI extraction, the date characters are then segmented and recognised. The proposed framework is the first to employ deep neural networks for end-to-end automatic use by date recognition in retail packaging photos. It is capable of achieving very good levels of performance on all the aforementioned tasks, despite the varied textual/pictorial content complexity found in food packaging design.","Title: Using News To Predict Chinese Medicinal Material Price Index Movements\nYear: 2018\n\nAbstract: Purpose The purpose of this paper is to propose an approach for predicting the movements of Chinese medicinal material price indexes using news based on text mining.Design/methodology/approach A research framework and three major methods, namely, domain dictionary construction, market convergence time calculation and dimensionality reduction integrating semantic analysis, are proposed for the approach. The proposed approach is applied in practice for predicting the price index movements of the top ten Chinese medicinal materials that receive the greatest media attention.Findings A set of experiments performed herein show that a predictive relationship exists between the news and the commodity market and that each of the three major methods improves the forecasting performance.Research limitations/implications Because the field of Chinese medicinal materials lacks a corpus that can be used for sentiment analysis, the accuracy of a trained automatic sentiment classifier is lower than obtained by a manual method, which can cause the calculated convergence result to be inaccurate, thus affecting the final prediction model. The manual method of having people label news decreases the proposed method's aspects of being intelligent and automatic.Practical implications Using the method proposed herein to predict the trends in Chinese medicinal materials prices helps farmers arrange a reasonable planting plan to pursue their best interests.Social implications The method proposed herein to predict the trends in the prices of Chinese medicinal materials is conducive to the government arranging planned drug availabilities in order to avoid disasters in which herbs are looted.Originality/value The produced prediction result is meaningful in supporting farmers and investors to make better decisions in growing and trading Chinese medicinal material, which leads to financial returns on investments and the avoidance of severe losses.","Title: Nuclear norm-based recursive subspace prediction of time-varying continuous-time stochastic systems via distribution theory.\nYear: 2018\n\nAbstract: •The random distribution theory is adopted to describe the time-derivative.•The method is generated by the ADMM and NNM, and extended to time-varying CT stochastic cases.•The prediction problem is solved by the rotation of the principal angle.","Title: Identification Of Unknown Operating System Type Of Internet Of Things Terminal Device Based On Ripper\nYear: 2018\n\nAbstract: Due to the vast popularity of sensors, cloud computing, mobile computing, and intelligent devices, the Internet of Things has seen tremendous growth in recent years. Operating system type recognition is the core technology of network security assessment. Due to inherit security problems of Internet of Things such as the situation of risk and threat of information, the operating system recognition seeks research attention for Internet of Things network security. In view of the current identification method of active operating system, it is prone to be detected by intrusion detection system. The operating system identification technology based on transmission control protocol/Internet protocol fingerprint library is more complicated than to distinguish the operating system types of unknown fingerprints. In this work, a passive operating system identification method based on RIPPER model is proposed. Also, it is compared with the existing support vector machine and C45 decision tree classification algorithms. Experiments reveal that RIPPER-based algorithm has better recognition accuracy and recognition efficiency.","Title: Human-Object Contour for Action Recognition with Attentional Multi-modal Fusion Network\nYear: 2019\n\nAbstract: Human action recognition has great research and application value in intelligent video surveillance, human-computer interaction and other communication fields. In order to improve the accuracy of human action recognition for video understanding, the extraction of human motion features and attentional fusion methods are studied. This paper has two main contributions. Firstly, based on the essence of optical flow validity, a novel dynamic feature expression method called Human-Object Contour(HOC) is presented, which combines object understanding and contextual information. Secondly, referring to the principle of Stacking in ensemble learning, we propose Attentional Multi-modal Fusion Network(AMFN). According to the characteristics of the video, attention is paid to selecting different modalities rather than simple averaging with fixed weight. The experiment shows that HOC is effectively complementary to the static appearance feature, and the accuracy of action recognition with our fusion network improves effectively. Our approach obtains the state-of-the-art performance on the datasets of HMDB51 (72.2%) and UCF101 (96.0%).","Title: Stability Analysis of PV Generators With Consideration of P&O-Based Power Control\nYear: 2019\n\nAbstract: Photovoltaic (PV) generators have continuously increased in recent years, whose power is usually controlled through the perturbation and observation (P&O) method. In essence, the P&O method is nonlinear and discontinuous. Hence, the conventional small-signal stability analysis is not suitable anymore when the influence of the P&O-based power control is considered. Focusing on this problem, this paper adopts the nonlinear describing function (DF) method to conduct the accurate stability analysis of PV generators with consideration of P&O-based power control. The detailed procedures about the DF method are introduced, and then the related influence factors like perturbation size, filters, and so on are analyzed quantitatively. Furthermore, the comparison with the conventional stability analysis methods is made, which suggests that the DF method can effectively enhance the accuracy of the stability analysis. All the conclusions are verified by the real-time hardware-in-loop tests.","Title: Progressive Pose Attention Transfer For Person Image Generation\nYear: 2019\n\nAbstract: This paper proposes a new generative adversarial network to the problem of pose transfer, i.e., transferring the pose of a given person to a target one. The generator of the network comprises a sequence of Pose-Attentional Transfer Blocks that each transfers certain regions it attends to, generating the person image progressively. Compared with those in previous works, our generated person images possess better appearance consistency and shape consistency with the input images, thus significantly more realistic-looking. The efficacy and efficiency of the proposed network are validated both qualitatively and quantitatively on Market-1501 and DeepFashion. Furthermore, the proposed architecture can generate training images for person re-identification, alleviating data insufficiency.","Title: Exploiting Emotions for Fake News Detection on Social Media.\nYear: 2019\n\nAbstract: Microblog has become a popular platform for people to post, share, and seek information due to its convenience and low cost. However, it also facilitates the generation and propagation of fake news, which could cause detrimental societal consequences. Detecting fake news on microblogs is important for societal good. Emotion is a significant indicator while verifying information on social media. Existing fake news detection studies utilize emotion mainly through users stances or simple statistical emotional features; and exploiting the emotion information from both news content and user comments is also limited. In the realistic scenarios, to impress the audience and spread extensively, the publishers typically either post a tweet with intense emotion which could easily resonate with the crowd, or post a controversial statement unemotionally but aim to evoke intense emotion among the users. Therefore, in this paper, we study the novel problem of exploiting emotion information for fake news detection. We propose a new Emotion-based Fake News Detection framework (EFN), which can i) learn content- and comment- emotion representations for publishers and users respectively; and ii) exploit content and social emotions simultaneously for fake news detection. Experimental results on real-world dataset demonstrate the effectiveness of the proposed framework.","Title: Motion Standard Level System Based On Internet Of Things\nYear: 2019\n\nAbstract: Recognition of motion level is a popular research area in the field of image processing in recent years. Based on the sensor equipment of action data acquisition, this article analyses the sensitivity of the micro-electro-mechanical system sensor. Then, according to the data-centric characteristics of the Internet of things, a distributed memory file storage and file writing system is constructed in the Internet of things environment, and the reliability and effectiveness of SensorFS are verified. Finally, dynamic time warping algorithm is used to evaluate the standard degree of human movement with dynamic time warping difference as experimental parameter, and a demonstration experiment of shadowboxing is designed to verify it. The result error is less than 0.05% by changing the standard of shadowboxing artificially, which proves the accuracy of the system. It provides a theoretical basis for the establishment of the standard system based on the Internet of things.","Title: Announcing Delay Information to Improve Service in a Call Center with Repeat Customers\nYear: 2019\n\nAbstract: We study the model of predicting and announcing delays, including customer satisfaction and repeat the behavior. In a call center, anticipated delays affect the customer behaviors of balking and reneging; we characterize the level of satisfaction with delay information to modulate customer reactions. In reality, a customer reacts by repeating behavior upon entering the service with a full perception of the delay. In particular, customers may feel dissatisfied when entering service because they have experienced a delay that is longer than announced. That is how satisfaction with delay information and waiting time affects customers' repeat behavior. Generally, customers may arrive at a higher rate when they are satisfied with the anticipated delay and the waiting experience in a call center. We characterize such performance measures using an M/M/S+M queue model. The revenue of a call center is generated by serving customers, and each time a customer abandons a call, the system loses revenue. Interestingly, the model reveals the revenue from the repeat behavior of satisfied customers. The formula used to approximate the arrival process reveals that traditional research could systematically underestimate the total number of call-ins and revenue. We show how call center managers can determine the most economically optimal anticipated delay so that they can control the trade-off between revenue loss and revenue from satisfaction.","Title: Analysis and prediction of human acetylation using a cascade classifier based on support vector machine.\nYear: 2019\n\nAbstract: Acetylation on lysine is a widespread post-translational modification which is reversible and plays a crucial role in some biological activities. To better understand the mechanism, it is necessary to identify acetylation sites in proteins accurately. Computational methods are popular because they are more convenient and faster than experimental methods. In this study, we proposed a new computational method to predict acetylation sites in human by combining sequence features and structural features including physicochemical property (PCP), position specific score matrix (PSSM), auto covariation (AC), residue composition (RC), secondary structure (SS) and accessible surface area (ASA), which can well characterize the information of acetylated lysine sites. Besides, a two-step feature selection was applied, which combined mRMR and IFS. It finally trained a cascade classifier based on SVM, which successfully solved the imbalance between positive samples and negative samples and covered all negative sample information. The performance of this method is measured with a specificity of 72.19% and a sensibility of 76.71% on independent dataset which shows that a cascade SVM classifier outperforms single SVM classifier. In addition to the analysis of experimental results, we also made a systematic and comprehensive analysis of the acetylation data.","Title: A network security entity recognition method based on feature template and CNN-BiLSTM-CRF.\nYear: 2019\n\nAbstract: By network security threat intelligence analysis based on a security knowledge graph (SKG), multi-source threat intelligence data can be analyzed in a fine-grained manner. This has received extensive attention. It is difficult for traditional named entity recognition methods to identify mixed security entities in Chinese and English in the field of network security, and there are difficulties in accurately identifying network security entities because of insufficient features extracted. In this paper, we propose a novel FT-CNN-BiLSTM-CRF security entity recognition method based on a neural network CNN-BiLSTM-CRF model combined with a feature template (FT). The feature template is used to extract local context features, and a neural network model is used to automatically extract character features and text global features. Experimental results showed that our method can achieve an F-score of 86% on a large-scale network security dataset and outperforms other methods.","Title: Wide-Area Damping Control Of The Time Delay Power System Based On An E-Trade Off \"Damping-Time Delay\" Method\nYear: 2018\n\nAbstract: With(1) the expansion of the scale of power system interconnection. The problem of low frequency oscillation of wide-area power system is more and more serious. Meanwhile, the transmission of wide-area signals will produce a time delay, and it can have great influence on the system stability. It is critically important to coordinate the relationship between the damping and the time delay, such that the power system remains stable. To achieve these objectives, we first construct, the reduced-order mathematical model of the power system. Then, a wide-area damping design method is developed based on an epsilon-tradeoff \"damping-time delay\". Using the linear matrix inequality toolbox and the Lyapunov stability criterion with time delay, parameters of the wide-area damping controller are obtained. Finally, we consider, as an example, a four -machine two-area model, and carry out simulations corresponding to different time delays using an iterative method. Simulation results show that WADC active power and rotor angle tend to be stable within 4 seconds. In addition, the damping stability of the power system is improved effectively compared with the control method based on common wide-area damping.","Title: Self-Adaptive Microjet Array Cooling For Rf High Power Gan Integration On Silicon\nYear: 2021\n\nAbstract: A novel Si interposer with microjet array cooling structure for RF high power GaN integration is presented in this work. The Si interposer is fabricated by stacking 3 wafers to form 2 layers of self-adaptive net microchannels and microjet array. The microfluids converge to form microjets in the bottom layer, then disperse in the top layer in 4 directions at net nodes. The cooling performance of the Si interposer is analyzed using finite element method (FEM) in COMSOL Multiphysics. The analysis results illustrate that the hotspot cooling capacity of the Si interposer depende largely on the flow rate of the coolant. The RF performance and temperature distribution of X-band GaN Monolithic Microwave Integrated Circuit (MMIC) power amplifier (PA) with static power density of similar to 480 W/cm(2) bonded on the Si interposer were measured in a test cube. The electrical measurement results validate that the cooling performance of the microjet impingement is able to provide the safety operating conditions of GaN MMIC PA. The thermal measurement results demonstrate that the hotspot cooling capacity of the Si interposer enabled GaN PA with hotspot heat density over 323.2 W/mm(2) to operate safely with low flow rate at 70 degrees C. The interposer is a promising solution for high power integration in silicon-based RF microsystem.","Title: Closed-loop delta-operator-based subspace identification for continuous-time systems utilising the parity space\nYear: 2021\n\nAbstract: This paper presents a closed-loop delta-operator-based subspace identification method for continuous-time systems utilising the parity space. The continuous-time systems are transformed to the delta-operator-based state space models which converge to the original systems with the sampling period going to zero. Instead of using the observable subspace, we focus on the parity space which is commonly employed in fault detection. The system is estimated consistently by the instrumental variable method and principal component analysis, which solves the identification problems of biased results as the system operates in closed-loop due to the feedback controller. The effectiveness of the proposed method is illustrated by simulation results.","Title: Deep Learning Based Prediction On Greenhouse Crop Yield Combined Tcn And Rnn\nYear: 2021\n\nAbstract: Currently, greenhouses are widely applied for plant growth, and environmental parameters can also be controlled in the modern greenhouse to guarantee the maximum crop yield. In order to optimally control greenhouses' environmental parameters, one indispensable requirement is to accurately predict crop yields based on given environmental parameter settings. In addition, crop yield forecasting in greenhouses plays an important role in greenhouse farming planning and management, which allows cultivators and farmers to utilize the yield prediction results to make knowledgeable management and financial decisions. It is thus important to accurately predict the crop yield in a greenhouse considering the benefits that can be brought by accurate greenhouse crop yield prediction. In this work, we have developed a new greenhouse crop yield prediction technique, by combining two state-of-the-arts networks for temporal sequence processing-temporal convolutional network (TCN) and recurrent neural network (RNN). Comprehensive evaluations of the proposed algorithm have been made on multiple datasets obtained from multiple real greenhouse sites for tomato growing. Based on a statistical analysis of the root mean square errors (RMSEs) between the predicted and actual crop yields, it is shown that the proposed approach achieves more accurate yield prediction performance than both traditional machine learning methods and other classical deep neural networks. Moreover, the experimental study also shows that the historical yield information is the most important factor for accurately predicting future crop yields.","Title: Adaptive Relay Strategy Selection Based On Q-Learning For Power Line And Wireless Dual-Media Communication With Hybrid Duplex\nYear: 2021\n\nAbstract: Relay algorithms in power line and wireless dual-media cooperative communication exhibit distinct advantages and disadvantages under random channels, and the algorithm that achieves the best performance can be determined through an adaptive relay strategy. However, the theoretical performance analysis of multiple relay algorithms for mixed fading and impulse noise encounters practical difficulties, such as lack of closed-form expressions and high complexity of the approximation process. This study proposes an adaptive relay strategy selection algorithm based on Q-learning, which can maximize the mutual information in the system. The feedback of the amount of mutual information is obtained by learning the dual-media cooperative communication environment of the time-varying fading channel to determine the optimal relay algorithm and power allocation factor. This study also analyzes the influence of the average signal-to-noise ratio, relay position, and power line channel parameters on the performance of the algorithm in terms of mutual information and outage probability and implements Q-learning-based relay strategy selection. Simulation results show that the proposed algorithm can obtain a quasi-optimal system performance in terms of the above two measures.","Title: Online Testing of Subgroup Treatment Effects Based on Value Difference\nYear: 2021\n\nAbstract: Online A/B testing plays a critical role in the high-tech industry to guide product development and accelerate innovation. It performs a null hypothesis statistical test to determine which variant is better. However, a typical A/B test presents two problems: (i) a fixed-horizon framework inflates the false-positive errors under continuous monitoring; (ii) the homogeneous effects assumption fails to identify a subgroup with a beneficial treatment effect. In this paper, we propose a sequential test for subgroup treatment effects based on value difference, named SUBTLE, to address these two problems simultaneously. The SUBTLE allows the experimenters to \"peek\" at the results during the experiment without harming the statistical guarantees. It assumes heterogeneous treatment effects and aims to test if some subgroup of the population will benefit from the investigative treatment. If the testing result indicates the existence of such a subgroup, a subgroup will be identified using a readily available estimated optimal treatment rule. We examine the empirical performance of our proposed test on both simulations and a real dataset. The results show that the SUBTLE has high detection power with controlled type I error at any time, is more robust to noise covariates, and can achieve early stopping compared with the corresponding fixed-horizon test.","Title: Thresholds Of Key Disaster-Inducing Factors And Drought Simulation In The Xilinguole Grassland\nYear: 2021\n\nAbstract: The frequency of extreme events such as droughts is increasing due to climate change. Grassland ecosystems are extremely sensitive to drought. This study aims to analyse how droughts respond to meteorological factors, establish a method to quantitatively evaluate the threshold values of key meteorological factors that can induce drought in different time periods, and explore a drought prediction model applicable to the Xilinguole Grassland. The Xilinguole Grassland has experienced an obvious aridification trend, with notable fluctuations in short dry and wet periods and the probability of drought (generally ranked in the order of moderate drought > light drought > severe drought > extreme drought). The Xilinguole Grassland is expected to face more intense drought conditions in the next 5 years. Among the meteorological elements, temperature, precipitation, water vapor pressure and solar radiation are the key factors influencing drought. Both short-term and long-term changes in precipitation and temperature have a strong influence on drought. Short-term changes in water vapor pressure have a significant impact on drought. Drought is sensitive to extreme climate events and is most sensitive to the influence of meteorological factors in May-September, particularly in July. In July, drought can be induced by any of the following: monthly precipitation below 50 mm, an average temperature above 23 degrees C, sunshine percentage above 69%, a monthly sunshine duration above 319 h, or an average water vapor pressure below 12 hPa. In addition, Markov chain modelling is a feasible approach for predicting drought in the Xilinguole Grassland. This study provides a scientific basis for drought prevention and control.","Title: A Novel Computer Vision-Based Data Driven Modelling Approach For Person Specific Fall Detection\nYear: 2021\n\nAbstract: In this paper, we propose a novel person specific fall detection system based on a monocular camera, which can be applied for assisting the independent living of an older adult living alone at home. A single camera covering the living area is used for video recordings of an elderly person's normal daily activities. From the recorded video data, the human silhouette regions in every frame are then extracted based on the codebook background subtraction technique. Low-dimensionality representative features of extracted silhouetted are then extracted by convolutional neural network-based autoencoder (CNN-AE). Features obtained from the CNN-AE are applied to construct an one class support vector machine (OCSVM) model, which is a data driven model based on the video recordings and can be applied for fall detection. From the comprehensive experimental evaluations on different people in a real home environment, it is shown that the proposed fall detection system can successfully detect different types of falls (falls towards different orientations at different positions in a real home environment) with small false alarms.","Title: Current-constrained finite-time control algorithm for DC-DC Buck converter\nYear: 2021\n\nAbstract: This paper studies the voltage regulation problem of Buck converter under current constraint. Firstly, to speed up the voltage regulation, a nonlinear algorithm is proposed to make the output voltage track the reference voltage quickly in a finite time. Meanwhile, to protect the devices in the circuit, the current-constraint problem is also considered in the finite-time controller design. In addition, the situation of load change is also considered. The proof of finite-time stability of the total closed-loop system is given and its validity is fully tested. Finally, simulation and experiment verify that the system has excellent dynamic performance and steady-state performance.","Title: Logistics cost control in food processing enterprises based on TD-ABC\nYear: 2021\n\nAbstract: In order to improve the logistics operation of food processing enterprises and control the logistics cost, this paper starts from the analysis of the logistics operation process and characteristics of enterprises, analyzes the logistics cost classification and composition of food processing enterprises, puts forward the basic process of applying TD-ABC to control the logistics cost, constructs the logistics cost accounting model of food processing enterprises based on TD-ABC, and puts forward relevant logistics cost control methods including the design of logistics cost control system, the determination of logistics cost control points and specific implementation steps. The typical food processing enterprises are selected for the empirical study of logistics cost accounting and controlling. By comparing the cost accounting results of TD-ABC and ABC, the result shows that TD-ABC (Time-Driven Activity-Based Costing) method can accurately grasp the logistics cost composition, identify inefficient logistics operations and non-value-added operations, and analyze the efficiency of various logistics departments, verify the feasibility and effectiveness of logistics cost accounting model and control method system, and provide some advice for logistics cost control and logistics process transformation of food processing enterprises.","Title: Reproducible untargeted metabolomics workflow for exhaustive MS2 data acquisition of MS1 features\nYear: 2022\n\nAbstract: Unknown features in untargeted metabolomics and non-targeted analysis (NTA) are identified using fragment ions from MS/MS spectra to predict the structures of the unknown compounds. The precursor ion selected for fragmentation is commonly performed using data dependent acquisition (DDA) strategies or following statistical analysis using targeted MS/MS approaches. However, the selected precursor ions from DDA only cover a biased subset of the peaks or features found in full scan data. In addition, different statistical analysis can select different precursor ions for MS/MS analysis, which make the post-hocvalidation of ions selected following a secondary analysis impossible for precursor ions selected by the original statistical method. Here we propose an automated, exhaustive, statistical model-free workflow: paired mass distance-dependent analysis (PMDDA), for reproducible untargeted mass spectrometry MS2 fragment ion collection of unknown compounds found in MS1 full scan. Our workflow first removes redundant peaks from MS1 data and then exports a list of precursor ions for pseudo-targeted MS/MS analysis on independent peaks. This workflow provides comprehensive coverage of MS2 collection on unknown compounds found in full scan analysis using a\"one peak for one compound\"workflow without a priori redundant peak information. We compared pseudo-spectra formation and the number of MS2 spectra linked to MS1 data using the PMDDA workflow to that obtained using CAMERA and RAMclustR algorithms. More annotated compounds, molecular networks, and unique MS/MS spectra were found using PMDDA compared with CAMERA and RAMCIustR. In addition, PMDDA can generate a preferred ion list for iterative DDA to enhance coverage of compounds when instruments support such functions. Finally, compounds with signals in both positive and negative modes can be identified by the PMDDA workflow, to further reduce redundancies. The whole workflow is fully reproducible as a docker image xcmsrocker with both the original data and the data processing template.","Title: Optimized Algebraic Reconstruction Algorithm Based Hemodynamic Changes in Color Doppler Ultrasound in Monitoring the Patients with Colorectal Cancer Undergoing Peripherally Inserted Central Catheter and Catheterization Nursing\nYear: 2021\n\nAbstract: The purpose of this study was to analyze the hemodynamic changes and nursing care of patients with colorectal cancer who were peripherally placed into the central venous catheter (PICC) by color Doppler ultrasound based on an optimized algebraic reconstruction (ART) (OART) algorithm. In this study, 150 patients with colorectal cancer were selected and randomly divided into observation group and control group, with 75 cases in each group. Different nursing interventions were carried out. An optimized algebraic reconstruction (OART) algorithm was proposed, and the traditional ART algorithm and filtered back-projection (FBP) algorithm were introduced for comparison. They were applied in ultrasounds of 150 colorectal cancer patients undergoing PICC. The results showed that the Dice coefficient (Dice) and peak signal-to-noise ratio (PSNR) of the OART algorithm were greater than those of the ART and FBP algorithms, while the difference function (DF) and the running time were opposite (P < 0.05). The blood flow velocity (BFV) and blood flow (BF) of the arm vein 5 days after puncture were the least, which were less than those before puncture and 10 days and 30 days after puncture (P < 0.05). Thrombosis was most likely to be found 4-6 days after puncture (28 cases), followed by 10-15 days after puncture (22 cases), and one day after the puncture (19 cases). The BFV and BF of patients with thrombosis were lower than those of patients without thrombosis (P < 0.05). The total infection rate of PICC in the observation group was 10.7%, which was lower than that in the control group 32.0%, P < 0.05. Nursing satisfaction of patients in observation group and control group was 95.99% and 75.99%, respectively, P < 0.05, and the difference was statistically significant. In short, the ORAT algorithm proposed had better performance than the traditional algorithms in ultrasound image reconstruction; strengthening nursing intervention for chemotherapy patients with colorectal cancer undergoing PICC could effectively reduce the infection rate of PICC and improve the nursing satisfaction of patients.","Title: Improving Column Generation for Vehicle Routing Problems via Random Coloring and Parallelization\nYear: 2022\n\nAbstract: We consider a variant of the vehicle routing problem (VRP) where each customer has a unit demand and the goal is to minimize the total cost of routing a fleet of capacitated vehicles from one or multiple depots to visit all customers. We propose two parallel algorithms to efficiently solve the column-generation-based linear-programming relaxation for this VRP. Specifically, we focus on algorithms for the \"pricing problem,\" which corresponds to the resource-constrained elementary shortest path problem. The first algorithm extends the pulse algorithm for which we derive a new bounding scheme on the maximum load of any route. The second algorithm is based on random coloring from parameterized complexity which can be also combined with other techniques in the literature for improving VRPs, including cutting planes and column enumeration. We conduct numerical studies using VRP benchmarks (with 50-957 nodes) and instances of a medical home care delivery problem using census data in Wayne County, Michigan. Using parallel computing, both pulse and random coloring can significantly improve column generation for solving the linear programming relaxations and we can obtain heuristic integer solutions with small optimality gaps. Combining random coloring with column enumeration, we can obtain improved integer solutions having less than 2% optimality gaps for most VRP benchmark instances and less than 1% optimality gaps for the medical home care delivery instances, both under a 30-minute computational time limit. The use of cutting planes (e.g., robust cuts) can further reduce optimality gaps on some hard instances, without much increase in the run time. Summary of Contribution: The vehicle routing problem (VRP) is a fundamental combinatorial problem, and its variants have been studied extensively in the literature of operations research and computer science. In this paper, we consider general-purpose algorithms for solving VRPs, including the column-generation approach for the linear programming relaxations of the integer programs of VRPs and the column-enumeration approach for seeking improved integer solutions. We revise the pulse algorithm and also propose a random-coloring algorithm that can be used for solving the elementary shortest path problem that formulates the pricing problem in the column-generation approach. We show that the parallel implementation of both algorithms can significantly improve the performance of column generation and the random coloring algorithm can improve the solution time and quality of the VRP integer solutions produced by the column-enumeration approach. We focus on algorithmic design for VRPs and conduct extensive computational tests to demonstrate the performance of various approaches.","Title: Non-Intrusive Adaptive Load Identification Based on Siamese Network\nYear: 2022\n\nAbstract: The traditional non-intrusive load monitoring (NILM) algorithms are mostly based on classification models, which have several deficiencies. Firstly, a large amount of labeled data is required to train the classification model. Secondly, these algorithms cannot identify unknown devices that frequently encountered in practical application. Finally, these models have poor performance in versatility, which means they only adapt to the trained data. These shortcomings greatly influence the practicality of these NILM algorithms. To tackle these problems, this paper has proposed a non-intrusive adaptive load identification model based on the Siamese network, which uses both the V-I trajectory and active power as the load signatures. The Siamese network is utilized to calculate the similarity of the V-I trajectory, and the load identification is realized by matching the signature with the feature library. Through adding new features to the feature library dynamically, the identification of unknown load can be realized. In addition, the Siamese network is a typical network for few-shot learning, thus the proposed model can be trained with a small number of samples to achieve ideal recognition effect. At last, the validity and versatility of the model are verified in PLAID dataset and COOLL dataset.","Title: MesoGRU: Deep Learning Framework for Mesoscale Eddy Trajectory Prediction\nYear: 2022\n\nAbstract: This work presents a novel framework, named MesoGRU, to accurately predict trajectories of mesoscale eddies (MEs), which is beneficial to study the natural ocean phenomena and perform statistical analysis of oceanic data. MesoGRU first extracts ME trajectory data and establishes two datasets according to the information of location and date in the South China Sea (SCS). Then it effectively processes SCS trajectory data and integrates SLA data and AVISO data into our combined ME dataset (CDME). Furthermore, a designated neural network with a new loss function [(weighted mean square estimation (WMSE)] is designed to learn the characteristics of ME trajectories. After thoroughly analyzing correlations of every two features, the MesoGRU network iteratively extracts key ME features and renormalizes the future time sequence of eddy trajectories. Our verification results demonstrate that MesoGRU has conducted a significant prediction improvement. The mean daily center error of ME trajectory prediction with our scheme is about 8 km and its center error for seven-day forecasting is approximately 18.2 km. Moreover, MesoGRU achieves a higher matching ratio of ME trajectory forecasting compared to other deep learning methods with a single dataset, indicating MesoGRU can predict trajectories as a state-of-the-art method.","Title: Intelligent Intrusion Detection Based on Federated Learning for Edge-Assisted Internet of Things\nYear: 2021\n\nAbstract: As an innovative strategy, edge computing has been considered a viable option to address the limitations of cloud computing in supporting the Internet-of-Things applications. However, due to the instability of the network and the increase of the attack surfaces, the security in edge-assisted IoT needs to be better guaranteed. In this paper, we propose an intelligent intrusion detection mechanism, FedACNN, which completes the intrusion detection task by assisting the deep learning model CNN through the federated learning mechanism. In order to alleviate the communication delay limit of federal learning, we innovatively integrate the attention mechanism, and the FedACNN can achieve ideal accuracy with a 50% reduction of communication rounds.","Title: An Eco-Driving Strategy for Partially Connected Automated Vehicles at a Signalized Intersection\nYear: 2022\n\nAbstract: We consider a signalized intersection under a partially connected automated vehicle (CAV) environment. There is a control center for the control zone that needs to predict the trajectories of human driving vehicles (HDVs) and control the trajectories of CAVs. By adopting model predictive control, we propose a real-time eco-driving strategy for the control center. In the proposed strategy, the Gipps' car-following model is selected to update the acceleration of HDV and an optimal control problem (OCP) is proposed to optimize the trajectory of each CAV based on real-time travel information. The control objective is to minimize the total fuel consumption of each CAV during the current control period. Pontryagin's minimum principle is employed to derive necessary optimality conditions under different scenarios. With the necessary optimality conditions, a numerical method is developed to solve the proposed OCP. Finally, numerical examples are provided to illustrate the performance of the proposed eco-driving strategy.","Title: AF Relaying Secrecy Performance Prediction for 6G Mobile Communication Networks in Industry 5.0\nYear: 2022\n\nAbstract: Industry 5.0 has developed in full swing, and accelerated the process of the sixth-generation (6G) mobile communication. Physical layer security is important for complex 6G mobile communication networks. To process active complex events in 6G mobile cooperative networks, predicting secrecy performance in time is essential for the mobile communication quality evaluation. Using amplify-and-forward (...","Title: Comparison of Pond Depth and Ice Thickness Retrieval Algorithms for Summer Arctic Sea Ice\nYear: 2022\n\nAbstract: In order to satisfy the demand of key sea ice parameters, including melt pond depth H-p and underlying ice thickness H-i, in studies of Arctic sea ice change in summer, four algorithms of retrieving H-p and H-i were compared and validated by using optical data of melt ponds from field observations. The Malinka18 algorithm stood out as the most accurate algorithm for the retrieval of H-p. For the retrieval of H-i, Malinka18 and Zhang21 algorithms could also provide reasonable results and both can be applied under clear and overcast sky conditions, while retrievals under clear sky conditions are more accurate. The retrieval results of H-i for Lu18 agreed better with field measurements for thin ice (H-i < 1 m) than that for thick ice, but those results of H-p were not satisfactory. The Konig20 algorithm was only suitable for clear sky conditions, and underestimated H-p, while showing a good agreement with H-p < 0.15 m. For Arctic applications, Malinka18 and Zhang21 algorithms provided a basis and reference for the satellite optical data such as WoeldView2 to retrieve H-p and H-i. Malimka18 also showed the ability to retrieve H-i, except for the Lu18 algorithm if pond color captured by helicopters and unmanned aerial vehicles were available. This study identifies the optimal algorithm for retrieval of H-p and H-i under different conditions, which have the potential to provide necessary data for numerical simulations of Arctic sea ice changes in summer.","Title: An end-to-end single image dehazing network based on U-net\nYear: 2022\n\nAbstract: Single image haze removal is always significant for computer advanced vision tasks, while it is also a challenging problem. In this paper, inspired of the recent methods, we proposed an end-to-end network with encoding–decoding structure and jumping layers for single image dehazing. The network combined the advantages of VGG16 and the U-net and adopted different jumping layers to retain most of the image feature information. In order to clarify the image features like contrast and color distribution, the scale-invariant loss function and the proposed histogram loss function were used. We compared the algorithm with the several state-of-the-art algorithms qualitatively and quantitatively. Experimental results demonstrated that the proposed algorithm has achieved favorable dehazing results on both indoor and outdoor synthetic hazy testing set and real-world set. In particular, it obtained the better dehazing results for the slight hazy conditions than other density of haze.","Title: SALSTM: An improved LSTM algorithm for predicting the competitiveness of export products\nYear: 2022\n\nAbstract: As international trade has been developing at an unprecedented rate, export product competitiveness is significant in a country's trade system. At present, neural network algorithms are extensively used in economic forecasting. Scholars have verified the effectiveness of neural networks, especially long short term memory (LSTM) model, compared with other nonlinear prediction methods. However, there are still research blanks in forecasting economic indicators related to export product competitiveness, and there is little research on the improved LSTM model combined with other algorithms. To address this limitation, this article established a quantitative index system for export product competitiveness composed of four highly recognized indicators such as revealed comparative advantage index, net export revealed comparative advantage index, international market share index, and economic value added. After collecting the relevant economic data, the single LSTM model was used to predict the future trend of China's machinery and equipment export product competitiveness. Based on the shortcomings exposed in applying single LSTM prediction, the article innovatively designs a combined forecast model of LSTM and seasonal autoregressive integrated moving average, and whose effectiveness and superiority are proved by the mean square error value. Finally, the article points out that this model plays an important role in national trade policy making. It is optimistic about the development of deep learning in international trade product competitiveness indicators prediction.","Title: Referral strategies and capacity decisions in a tiered hospital system with gatekeeping designs — Exemplified with Chinese healthcare system\nYear: 2022\n\nAbstract: We developed a model to formulate the referral process in a tiered hospital system involving a general hospital (GH) and community healthcare centers (CHCs), where green channels are built on priority. We propose two types of referral strategies to address delay-sensitive patients based on: (1) patients’ choice (PC) and (2) independent decision-making by the hospital (DMH). Through price subsidy and priority mechanism, both PC and DMH can effectively regulate patient choice behavior and guide all patients to choose a CHC for the first diagnosis. This could help the Chinese government implement a gatekeeping system even if free referral of patients is allowed. We determine the optimal capability decisions of the GH (for profit maximization) and each CHC (for maximization of patient utility), under two strategies. The main results are as follows: under PC, the referral process is controlled by the GH, but the government’s coordination tools (budget and tax rate) would not influence the GH’s decision on its optimal arrival rate with the green channel. In contrast, DMH offers the government more power to control the referral process using budget and tax rate. Numerical analysis provides managerial insights for the government to better use tax-subsidy policies and make an optimal choice between PC and DMH.","Title: A Novel Transformer-Based Model for Dialog State Tracking\nYear: 2022\n\nAbstract: Dialog state tracking (DST) is a core component in the task-oriented dialog systems. Many previous approaches regard DST as a classification task for a set of predefined slot-value pairs, but these approaches can not handle the situation of dynamic ontology. Other methods consider slot as span-based, while these methods are insufficient when the target slot-value cannot be found as a word segment in the dialog context. To mitigate these problems, we propose a Transformer-based model for DST. The proposed method can achieve the DST task by extracting the slot-value from the dialog context or classifying for the slot with limited values. Experimental evidence shows that our proposed model can achieve competitive performance on the WOZ 2.0 dataset while being 20\n \n \n \n $$\\times $$\n \n faster than the state-of-the-art model. To demonstrate the effectiveness of our proposed model on multi-domain, we experiment with the recently released MultiWOZ-2.0 dataset. The experiment shows that our model can achieve promising result.","Title: Accurate and Efficient Performance Prediction for Mobile IoV Networks Using GWO-GR Neural Network\nYear: 2022\n\nAbstract: The explosive growth of Internet of Vehicle (IoV) applications has made information security a significant issue. Mobile IoV users are dynamic and the communication environment is very complex, which makes it very difficult to guarantee real-time secrecy communication performance. Thus, a reliable and effective evaluation and prediction of secrecy performance is critical. In this article, we have derived novel expressions for secrecy performance. A grey wolf optimization generalized regression (GWO-GR) algorithm is proposed to predict the secrecy performance and carry out the secrecy performance assessment. A generalized regression (GR) neural network is designed. Out of the input and output layers, the proposed GR network has a pattern layer and a summation layer, which can obtain a global convergence of network results. To further optimize the GR network, the grey wolf optimization algorithm is used to obtain the best spread factor for it, which can accelerate its rapid convergence. Through the simulated numerical results, we can obtain: 1) the proposed GWO-GR prediction algorithm is shown to provide better performance prediction results than other machine-learning-based methods; 2) in particular, the prediction accuracy is improved by 17.7%; and 3) the execution time has an 88.9% reduction.","Title: Trampoline Over the Air: Breaking in IoT Devices Through MQTT Brokers\nYear: 2022\n\nAbstract: MQTT is widely adopted by IoT devices because it allows for the most efficient data transfer over a variety of communication lines. The security of MQTT has received increasing attention in recent years, and several studies have demonstrated the configurations of many MQTT brokers are insecure. Adversaries are allowed to exploit vulnerable brokers and publish malicious messages to subscribers. However, little has been done to understanding the security issues on the device side when devices handle unauthorized MQTT messages. To fill this research gap, we propose a fuzzing framework named ShadowFuzzer to find client-side vulnerabilities when processing incoming MQTT messages. To avoiding ethical issues, ShadowFuzzer redirects traffic destined for the actual broker to a shadow broker under the control to monitor vulnerabilities. We select 15 IoT devices communicating with vulnerable brokers and leverage ShadowFuzzer to find vulnerabilities when they parse MQTT messages. For these devices, ShadowFuzzer reports 34 zero-day vulnerabilities in 11 devices. We evaluated the exploitability of these vulnerabilities and received a total of 44,000 USD bug bounty rewards. And 16 CVE/CNVD/CN-NVD numbers have been assigned to us.","Title: A Multilevel Remote Relational Modeling Network for Accurate Segmentation of Fundus Blood Vessels\nYear: 2022\n\nAbstract: Accurate segmentation of retinal blood vessels is an important prerequisite for diagnosing many fundus diseases. Many methods based on artificially designed convolutional neural networks (CNNs) have been successively proposed and achieved good results. However, the image quality collected by fundus camera is poor, and the vessels topology in the image is complex, the pure convolution feature extraction in these CNN methods is limited. A novel multilevel remote relational modeling network (MRRM-Net) is proposed, which can balance global/local long-range contextual relations through building multidimensional and multilevel attention. Based on the symmetric structure, we first design the three-dimensional guided attention module (TGAM) in the encoder to establish long-range dependency descriptions with semantically rich spatial structure through similarity and then design a cross-level sensitive attention module (CSAM) at the skip connection position to adaptively and dynamically correct low-level error information while strengthening the long-range spatial structure features established by the attention guidance module. These two modules can gradually establish and fuse the long-range semantic context. Furthermore, we propose a novel feature fusion method (FFM) to pass high-level semantics into the decoder. The experimental results show that our proposed method has better superiority, especially for capillaries with complex background and variable structure, and has more robust data adaptability than other state-of-the-art network structures in a small capacity. On multiple public datasets, it shows better stability. MRRM-Net can provide a theoretical basis for real-time detection technology of retinopathy.","Title: A Review of Virtual Reality in Language Learning from 2011 to 2020\nYear: 2022\n\nAbstract: The utilization of virtual reality (VR) in the field of language learning is a hot issue for both educational practitioners and researchers. This research summarized the empirical studies on applying VR in language learning from 2011 to 2020. The authors analyzed a total of 67 empirical studies in twelve peer-reviewed journals. On the basis of the coding framework, we used content analysis for further data analysis. The current study revealed the general research status, major research themes of the empirical studies and the guiding theories for the instructional design with VR. The advantages and challenges of integrating VR to language learning were summarized in the end."],"string":"[\n \"Title: Design and Implementation of Common Map Symbol System in GIS\\nYear: 2008\\n\\nAbstract: Map symbol has important effect in the process of GIS graphics. This paper introduce a GIS common symbol library, which is designed and implemented based on MapObjects' interface, include point symbol, line symbol and fill symbol and further illustration on how to save symbol in commercial database. At last, a case that using this symbol library is shown. This is a result tested in Zhejiang province in the Chinese numerical marine project and it achieves a good result.\",\n \"Title: A posture recognition based fall detection system for monitoring an elderly person in a smart home environment.\\nYear: 2012\\n\\nAbstract: We propose a novel computer vision based fall detection system for monitoring an elderly person in a home care application. Background subtraction is applied to extract the foreground human body and the result is improved by using certain post-processing. Information from ellipse fitting and a projection histogram along the axes of the ellipse are used as the features for distinguishing different postures of the human. These features are then fed into a directed acyclic graph support vector machine (DAGSVM) for posture classification, the result of which is then combined with derived floor information to detect a fall. From a dataset of 15 people, we show that our fall detection system can achieve a high fall detection rate (97.08%) and a very low false detection rate (0.8%) in a simulated home environment.\",\n \"Title: Research on Coupling Characters of the Linear Polarized Mode between Two Multi-mode Silica Circular Waveguide.\\nYear: 2011\\n\\nAbstract: Based on fiber coupling equation, this paper discusses the character of linear polarized mode coupling between two multi-mode silica circular waveguides which have the same dopant distribution. The Eigen values of linear polarized mode U, W are calculated based on the Eigen value equations. According to the numerical calculation, coupling coefficient and coupling length in different coupling angles are given, and the method to improve the efficiency of multimode fiber coupling is summarized.\",\n \"Title: VGRIS: virtualized GPU resource isolation and scheduling in cloud gaming\\nYear: 2013\\n\\nAbstract: Fueled by the maturity of virtualization technology for Graphics Processing Unit (GPU), there is an increasing number of data centers dedicated to GPU-related computation tasks in cloud gaming. However, GPU resource sharing in these applications is usually poor. This stems from the fact that the typical cloud gaming service providers often allocate one GPU exclusively for one game. To achieve the efficiency of computational resource management, there is a demand for cloud computing to employ the multi-task scheduling technologies to improve the utilization of GPU.\\n\\nIn this paper, we propose VGRIS, a resource management framework for Virtualized GPU Resource Isolation and Scheduling in cloud gaming. By leveraging the mature GPU paravirtualization architecture, VGRIS resides in the host through library API interception, while the guest OS and the GPU computing applications remain unmodified. In the proposed framework, we implemented three scheduling algorithms in VGRIS for different objectives, i.e., Service Level Agreement (SLA)-aware scheduling, proportional-share scheduling, and hybrid scheduling that mixes the former two. By designing such a scheduling framework, it is possible to handle different kinds of GPU computation tasks for different purposes in cloud gaming. Our experimental results show that each scheduling algorithm can achieve its goals under various workloads.\",\n \"Title: A study of the inverse dynamics of a hybrid polishing kinematical machine tool based on the flexible multi-body systems\\nYear: 2007\\n\\nAbstract: This paper presents a novel five DOF hybrid polishing kinematical machine tool (ffPKMT) which is made up of \\\"3 axes parallel + 2 axes series\\\" in order to obtain more stable machining result in the elastic polishing on the free-form surfaces. The dynamic characteristics of the HPKMT is studied in detail by means of the theory of dynamics of flexible multi-body systems. In order to control the HPKMT effectively, its characteristic of the kinematics and dynamics need be known deeply. The analysis of the inverse of mechanism is the important part in the research of dynamics. Adopting the same experiment condition with simulation analysis, the inverse kinematical trace of the three sliders can be obtained. It is shown that the simulation result is almost the same as the measured result from the experiment.\",\n \"Title: Acceleration of fast factorized back projection algorithm for bistatic SAR\\nYear: 2013\\n\\nAbstract: In this paper, we present an accelerated fast factorized back-projection algorithm designed for bistatic SAR data. This method supports a precise bistatic SAR image reconstruction and can attain high execution efficiency. Key to this method is the optimized parallel implementation of the original algorithm that can be executed on GPU. We make effort to a parallelization of factorized back-projection by a reasonable parallel strategy so that it can be implemented by CUDA on GPU. Moreover, we also do some optimization for a further improvement, including memory optimization and phase compute optimization, and when it comes to the translational-invariant data, an extra slant range compute optimization have been done yet. The validity and advantage of proposed approach are verified by simulated X-band bistatic SAR data and experimental data.\",\n \"Title: Blind Separation of DS-CDMA Signals with ICA Method.\\nYear: 2011\\n\\nAbstract: The Estimation of pseudo noise sequence and information sequence is of great importance in the security of DS-CDMA system, which remains a hot research problem in reconnaissance and supervision of wireless communication. In DS-CDMA system, the pseudo noise sequences of different users are uncorrelated and the information sequences of different users are statistical independent, thus independent component analysis (ICA) could be introduced to separate the DS-CDMA signals with little prior knowledge. In multipath situations, the recovered pseudo noise sequence with ICA is overlapped. For DSCDMA signals which utilize m-sequence as pseudo noise sequence, the triple correlation function (TCF) is introduced to eliminate the influence of overlap in this paper, which increases the estimation correct ratio greatly. Under the non-cooperative conditions, it is very difficult for the interceptor to aim at the very beginning of the transmitted signal. Certain offsets between the interceptor and the transmitter deteriorate the blind separation method obviously. The relationship between none convergence and the offset is found out and explained from eigen value decomposition. The validity of the proposed method and theory analysis is proved well by the simulation results at last. © 2011 Academy Publisher.\",\n \"Title: A scalable key management and clustering scheme for ad hoc networks\\nYear: 2006\\n\\nAbstract: This paper describes a scalable key management and clustering scheme for secure group communications in ad hoc and sensor networks. The scalability problem is solved by partitioning the communicating devices into subgroups, with a leader in each subgroup, and further organizing the subgroups into hierarchies. Each level of the hierarchy is called a tier or layer. Key generation, distribution, and actual data transmissions follow the hierarchy. The Distributed, Efficient Clustering Approach (DECA) provides robust clustering to form subgroups, and analytical and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility. Comparing with most other schemes, our approach is extremely scalable and efficient, provides more security guarantees, and is selective, adaptive and robust.\",\n \"Title: Selection Cooperation in Heterogeneous Cooperative Networks.\\nYear: 2014\\n\\nAbstract: Selection cooperation is an attractive cooperative strategy for wireless networks due to its simplicity and efficiency. In this paper, we consider a heterogeneous cooperative network consisting of different kinds of nodes with low-cost radios where the activities of one kind of nodes are triggered by the other kinds of nodes. This is a common scenario for many networks, such as wireless sensor networks. By exploiting the transmission relationship between heterogeneous nodes, we propose a selection cooperation protocol where inducing nodes can cooperate with the following nodes after their own transmissions for improving the communication reliability of the latter nodes. Through performance analysis, we show an interesting feature that the diversity-multiplexing tradeoff of the proposed protocol does not rely on the best relay selection method and the protocol always achieves the full diversity gain. We further develop an energy-efficient best relay selection method based on power control where the power consumption is minimized without decreasing the full diversity order. Simulation results demonstrate the good performance of the protocol and the remarkable energy reduction of the proposed best relay selection method.\",\n \"Title: Vis: virtualization enhanced live acquisition for native system\\nYear: 2011\\n\\nAbstract: Focusing on obtaining in-memory evidence, current live acquisition efforts either fail to provide accurate native system physical memory acquisition at the given time point or require suspending the machine and altering the execution environment drastically. To address this issue, we propose Vis, a light-weight virtualization approach to provide accurate retrieving of physical memory content while preserving the execution of target system. Vis encapsulates the native system into a single virtual machine and then conducts accurate acquisition by manipulating nested page table in hypervisor. We present the design and implementation of Vis, prove its acquisition reliability and evaluate its performance in live acquisition scenarios.\",\n \"Title: A recurrent neural network modeling for automotive magnetorheological fluid shock absorber\\nYear: 2005\\n\\nAbstract: Automotive Magnetorheological (MR) fluid shock absorbers have been previously characterized by a series of nonlinear differential equations, which have some difficulties in developing control systems. This paper presents a recurrent neural network with 3 input neurons, 1 output neuron and 5 recurrent neurons in the hidden layer to simulate behavior of MR fluid shock absorbers to develop control algorithms for suspension systems. A recursive prediction error algorithm has been applied to train the recurrent neural network using test data from lab where the MR fluid shock absorbers were tested by the MTS electro-hydraulic servo vibrator system. Training of neural network model has been done by means of the recursive prediction error algorithm presented in this paper and data generated from test in laboratory. In comparison with experimental results of MR fluid shock absorbers, the neural network models are reasonably accurate to depict performances of MR fluid shock absorber over a wide range of operating conditions.\",\n \"Title: An online one class support vector machine-based person-specific fall detection system for monitoring an elderly individual in a room environment.\\nYear: 2013\\n\\nAbstract: In this paper, we propose a novel computer vision-based fall detection system for monitoring an elderly person in a home care, assistive living application. Initially, a single camera covering the full view of the room environment is used for the video recording of an elderly person's daily activities for a certain time period. The recorded video is then manually segmented into short video clips containing normal postures, which are used to compose the normal dataset. We use the codebook background subtraction technique to extract the human body silhouettes from the video clips in the normal dataset and information from ellipse fitting and shape description, together with position information, is used to provide features to describe the extracted posture silhouettes. The features are collected and an online one class support vector machine (OCSVM) method is applied to find the region in feature space to distinguish normal daily postures and abnormal postures such as falls. The resultant OCSVM model can also be updated by using the online scheme to adapt to new emerging normal postures and certain rules are added to reduce false alarm rate and thereby improve fall detection performance. From the comprehensive experimental evaluations on datasets for 12 people, we confirm that our proposed person-specific fall detection system can achieve excellent fall detection performance with 100% fall detection rate and only 3% false detection rate with the optimally tuned parameters. This work is a semiunsupervised fall detection system from a system perspective because although an unsupervised-type algorithm (OCSVM) is applied, human intervention is needed for segmenting and selecting of video clips containing normal postures. As such, our research represents a step toward a complete unsupervised fall detection system.\",\n \"Title: Sensor Response and Sensor Network Development for Practical Combustors\\nYear: 2007\\n\\nAbstract: Meeting environmentally benign clean energy demands with expected growing population in the near term requires the development of smarter combustors and power plants. The future power plants will need to be more efficient and emit near zero emissions. This will require a significantly improved realtime control and analysis system. A single sensor from a combustor or any component in a power plant unit provides inadequate information about the fate of various ongoing processes within the system. We envision that future advanced power plants will have a large number of sensors to provide comprehensive information about the fate of various ongoing processes in the combustion system. Incorporating a large number of sensors in a sensor network will allow one to obtain comprehensive information, which can then be processed to visually display the detailed behavior in real time and support advanced control systems that can formulate the plant behavior. In this paper, we provide systematic development of a single sensor response from a combustor to understand the sensor's response on location and operational parameters. The results reveal the need for multiple sensor arrays for detailed visualization, analysis, and process control. These results will be used as a guideline for determining the type and nature of high density sensor network around the combustor of a power plant. Different issues and algorithms about high-density sensor networks in advanced combustors are also discussed.\",\n \"Title: Average filtered blind separation of DS-CDMA signals with ICA method\\nYear: 2010\\n\\nAbstract: In DS-CDMA system, the pseudo random sequences are none correlation and the information sequences of different user's are independent, thus Independent Component Analysis (ICA) is appropriate for the blind separate the DS-CDMA signals with little prior knowledge. Original blind separation method of DS-CDMA signals with ICA utilized only one sample value in each chip. However, in common DS-CDMA communication systems, the sample rate is much faster than the chip rate, so there are many samples during a chip interval. A method of average filtered blind separation of DS-CDMA signals with ICA is proposed in this paper. When noise is stationary, the method proposed could increase the input SNR of ICA greatly. The validity of the method is proved by the simulation results at last.\",\n \"Title: Sensor coverage in wireless ad hoc sensor networks\\nYear: 2007\\n\\nAbstract: We present our solutions to the general sensor coverage problem in wireless ad hoc sensor networks, where the sensors are heterogeneous in terms of sensing, communication and motion capabilities. We propose an integrated framework to accommodate such heterogeneity, in which sensors are logically organised into different tiers. We then address, for each given set of heterogeneous sensors, how the coverage problem can be solved. We first present our Sensing Neighbour Acquiring Protocol (SNAP) which renders correct neighbour information necessary for coverage algorithms. Then we provide our insights on coverage and the necessary and sufficient conditions for the coverage degree determination in a target area. Such theoretical results lead to our general and efficient coverage determination algorithm. Further, we prove that by using SNAP, coverage implies network connectivity. Without assuming uniform sensing ranges, our protocol, algorithm and theoretical results are generally applicable in a wide range of sensor network applications.\",\n \"Title: Moderate deviation principle for autoregressive processes\\nYear: 2009\\n\\nAbstract: A moderate deviation principle for autoregressive processes is established. As statistical applications we provide the moderate deviation estimates of the least square and the Yule-Walker estimators of the parameter of an autoregressive process. The main assumption on the autoregressive process is the Gaussian integrability condition for the noise, which is weaker than the assumption of Logarithmic Sobolev Inequality in [H. Djellout, A. Guillin, L. Wu, Moderate deviations of empirical periodogram and nonlinear functionals of moving average processes, Ann. I. H. Poincare-PR 42 (2006) 393-416].\",\n \"Title: Discrete-time adaptive learning control for parametric uncertainties with unknown periods\\nYear: 2013\\n\\nAbstract: In this paper, we approach the problem of unknown periods for a class of discrete-time parametric nonlinear systems with nonlinearities which do not necessarily satisfy the sector-bounded condition. The unknown periods hide in the parametric uncertainties, which is difficult to estimate. By incorporating a logic-based switching mechanism, we estimate the period and bound of unknown parameter simultaneously under Lyapunov-based analysis. Rigorous proof is given to demonstrate that a finite number of switchings can guarantee the asymptotic regulation of the nonlinear system considered. The simulation result also shows the efficacy of the proposed switching periodic adaptive control method.\",\n \"Title: Adaptive fuzzy neural network control for transient dynamics of magneto-rheological suspension with time-delay\\nYear: 2006\\n\\nAbstract: Since Magneto-rheological (MR) suspension has nonlinearity and time-delay, the application of linear feedback strategy has been limited. This paper addresses the problem of control of MR suspension with time-delay when transient dynamics are presented. An adaptive Fuzzy-Neural Network Control (FNNC) scheme for the transient course is proposed using fuzzy logic control and artificial neural network methodologies. To attenuate the adverse effects of time-delay on control performance, a Time Delay Compensator (TDC) is established. Then, through a numerical example of a quarter car model and a real road test with a bump input, the comparison is made between passive suspension and semi-active suspension. The results show that the MR vehicle with FNNC strategy can depress the peak acceleration and shorten the setting time, and the effect of time-delay can be attenuated. The results of road test with the similarity of numerical study verify the feasibility of the control strategy.\",\n \"Title: Detecting and visualizing cartilage thickness without a shape model\\nYear: 2012\\n\\nAbstract: This paper proposes a cartilage thickness detection and visualization method that does not utilize a shape model. The proposed method consists of three parts: volume of interest (VOI) initialization, bone segmentation, and cartilage thickness visualization. For VOI initialization, a novel 3D U-shape cuboidal filter is proposed to detect individual bones such as the femur, tibia, and patella, and for bone segmentation, a hybrid level-set method is adopted. Finally, a surface normal based approach is presented for measuring and visualizing the cartilage thickness. The advantage of the proposed method compared to other methods is that it does not require a shape model or any training process. The results demonstrate that the proposed method can be used for inspecting cartilage damage and loss.\",\n \"Title: A robust fall detection system for the elderly in a Smart Room\\nYear: 2010\\n\\nAbstract: In this paper, we propose a novel and robust fall detection system by using a density method for modeling a fall event as a function of certain video feature.3-D head velocity and human shape information are extracted as feature and three types of density model, single Gaussian, mixture of Gaussians and Parzen window method, are constructed for modeling the density of fall with respect to the extracted video feature. Falls are then detected according to the corresponding obtained density model and the success of the method is confirmed on real video sequences.\",\n \"Title: A distributed efficient clustering approach for ad hoc and sensor networks\\nYear: 2005\\n\\nAbstract: This paper presents a Distributed, Efficient Clustering Approach (DECA) for ad hoc and sensor networks. DECA can provide robustness against moderate node mobility and at the same time render energy-efficiency. The identified clusterheads cover the whole network and each node in the network can determine its cluster and only one cluster. The algorithm terminates in deterministic time without iterations, and each node transmits only one message during the algorithm. We prove analytically the correctness and complexity of the algorithm, and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility.\",\n \"Title: A Lightweight Selection Cooperation Protocol with Multiple Available Best Relays\\nYear: 2013\\n\\nAbstract: Selection cooperation has shown to be a practical cooperative strategy for wireless networks. In order to obtain full diversity gain, conventional selection cooperation schemes must select the node with the maximum relay-destination channel as the best relay, which restricts the choice of relay selection for the system. To overcome this limitation, we propose a lightweight selection cooperation protocol without requiring the radio of nodes to perform combining reception. Through outage probability and diversity-multiplexing tradeoff (DMT) analysis, we reveal an interesting fact that choosing any node that successfully receives the message from the source and the feedback frame from the destination as the best relay, the protocol always achieves the full diversity order and the optimal DMT. This result establishes a framework for obtaining multiple optimization objectives in selection cooperation networks. As an illustrative example, we then develop two best relay selection methods for relay balance without sacrificing the full diversity order. Simulation results demonstrate the remarkable performance and balance effect of the proposed protocol and selection methods.\",\n \"Title: Design and fabrication of flexible parylene-based inductors with electroplated NiFe magnetic core for wireless power transmission system\\nYear: 2012\\n\\nAbstract: Integrated flexible parylene-based MEMS inductors were successfully designed, fabricated and analyzed. By elctrodeposition technique, Ni80Fe20 Permalloy with high permeability was acquired as the magnetic core to increase the inductance and quality factor of inductors. Using parylene as substrates, these inductors became more flexible and biocompatible. For small scale inductors, by HFSS simulation, a maximum quality factor of 51.52 was achieved at 3.10 GHz. The inductance of inductors with magnetic core was enhanced by 3.3% than those with air core. As the width of the core increased from 25 μm to 100 μm, the inductance was also increased by 11.3% maximally. For large scale inductors fabricated, the tested maximum quality factor was 110 at 6 MHz. Based on the IC compatible fabrication process, these inductors could be used in wireless power transmission system for implantable medical devices.\",\n \"Title: Convergence characteristics analysis on blind separation of DS-CDMA signals with ICA method\\nYear: 2010\\n\\nAbstract: Blind estimation of information sequences and pseudo random sequences is of great importance for the security in DS-CDMA system, which remains a hot research topic in reconnaissance and supervision of wireless communication. In DS-CDMA system, the information sequences of different user's are independent and the pseudo random sequences are none correlation, thus independent component analysis (ICA) technology can be adopted to separate the DS-CDMA signals with little prior knowledge. Under non-cooperative situations, the interceptor could not aim at the beginning of the symbol accurately. The offset between the transmitter and the interceptor has great influence on the convergence characteristic of the blind separation algorithm of DS-CDMS signals with ICA method. Certain offsets deteriorate the convergence characteristic obviously. The relationship between the offset and the convergence characteristics is found out, which has great importance in choosing the offset in practice. The reason why certain offsets deteriorate the algorithm is analyzed from the idea of eigen value decomposition. The correctness of theory analysis is proved by the simulation results at last.\",\n \"Title: VASP: virtualization assisted security monitor for cross-platform protection\\nYear: 2011\\n\\nAbstract: Numerous operating systems have been designed to manage and control system resources with large and complicated features, so they need high security protection. However, previous security applications can not provide adequate protection due to the untrusted execution environment. Furthermore, these security strategies cannot support a universal cross-platform system security requirements. This paper presents VASP, a hypervisor based monitor which allows a trusted execution environment to monitor various malicious behaviors in the operating system. This is achieved by taking advantage of ×86 hardware virtualization and self-transparency technology, and providing a unified security protection to unmodified operating systems such as Linux and Windows. Our design is targeted at establishing a security monitor which resides completely outside of the target OS environment with a negligible overhead. According to the security analysis and performance experiment result, our approach can effectively protect applications and the kernel at a modest overhead of only 0.9% average in Windows XP and 2.6% average in Linux.\",\n \"Title: SPAD: software protection through anti-debugging using hardware virtualization\\nYear: 2011\\n\\nAbstract: Debugging could be a threat to system security when adopted by malicious attackers. The major challenges of software-only anti-debugging are compromised strategy and lack of self-protection. Leveraging hardware virtualization, we proposes a strategy of software protection through anti-debugging which imperceptibly monitors the debug event on a higher privilege level than the conventional kernel space. Our prototype can effectively prohibit the debugging behavior from selected popular debuggers in the replication experiment.\",\n \"Title: HBSP: A Lightweight Hardware Virtualization Based Framework for Transparent Software Protection in Commodity Operating Systems\\nYear: 2009\\n\\nAbstract: Commodity operating systems are usually large and complex, leading host-based security tools often provide inadequate protection against malware because execution environment for software is untrusted. As a result, most software currently uses various ways to defend malware attacks. However, these approaches not only raise the complexity of the software but also fail to offer an engrained security solution. The focal point in the software protection battle is how to protect effectively versus how to conceal the protector from untrusted OSes. This paper describes a lightweight, transparent and flexible architecture framework called HBSP (Hypervisor Based Software Protector)for software protection. HBSP, which is based on hardware virtualization extension technology such as Intel VT, and by taking advantage of Memory-Hiding strategy, resides completely outside of the target OS environment. Our security analysis and the performance experiment results demonstrate that HBSP effectively protects applications running on unmodified Windows XP, while the total overhead is only 0.25% in average.\",\n \"Title: Neural Networks Based Image Recognition: A New Approach\\nYear: 2007\\n\\nAbstract: In this paper, a new application algorithm for image recognition based on neural network has been pro-posed. The present algorithm including recognition algorithm and algorithm for training BP neural network can recognize continually changing large gray image. This algorithm has been applied to deflection measurement of bridge health monitoring, and achieved a great success.\",\n \"Title: A scalable key management and clustering scheme for wireless ad hoc and sensor networks\\nYear: 2008\\n\\nAbstract: This paper describes a scalable key management and clustering scheme for secure group communications in ad hoc and sensor networks. The scalability problem is solved by partitioning the communicating devices into subgroups, with a leader in each subgroup, and further organizing the subgroups into hierarchies. Each level of the hierarchy is called a tier or layer. Key generation, distribution, and actual data transmissions follow the hierarchy. The distributed, efficient clustering approach (DECA) provides robust clustering to form subgroups, and analytical and simulation results demonstrate that DECA is energy-efficient and resilient against node mobility. Comparing with most other schemes, our approach is extremely scalable and efficient, provides more security guarantees, and is selective, adaptive and robust.\",\n \"Title: Vis: Virtualization enhanced live forensics acquisition for native system.\\nYear: 2012\\n\\nAbstract: Current live acquisition systems can obtain memory content of a running system, but they either fail to provide accurate native system physical memory acquisition at the given time point or require suspending the machine and altering the execution environment drastically. To address this issue, we propose Vis, a lightweight virtualization approach to provide accurate retrieval of physical memory content without disturbing the execution of the target native system. Our experimental results indicate that Vis is capable of reliably retrieving an accurate system image. Moreover, Vis accomplishes live acquisition in around 100 s, where previous remote live acquisition tools take hours and static acquisition takes days. On average, the performance reduction for the target system is 9.62%.\",\n \"Title: A Multi-objective Cross-training Plan Based on NSGA-II.\\nYear: 2013\\n\\nAbstract: The previous research on cross-training mainly focused on productive efficiency. However, enhancing labor's satisfaction of tasks is as much important as improving production performance. This paper addresses a new cross-training policy for an assembly cell from the point of view of humanization. A multi-objective 0-1 integer programming model is presented to implement the crosstraining policy for an assembly cell. The first objective works on getting to maximize average satisfaction degree, and the second objective seeks to minimize average paid salary, while determining which labors should be cross-trained on which tasks. Non-dominated sorting genetic algorithm (NSGA-II) is developed to solve the model. A series of computational experiments are proceeded to explore the impact of three factors on cross-training, including labor's preference structure, labor's salary structure, and task redundancy. The results indicate that the balanced preference structure is better than the extreme one, the non-uniform salary structure is better than the uniform one, and the smaller task redundancy is better than the bigger one under various scenarios in the paper. Those insights can be used to direct the managers of human resource to choose the candidates for cross-training. © 2013 ACADEMY PUBLISHER.\",\n \"Title: Fall detection in a smart room by using a fuzzy one class support vector machine and imperfect training data\\nYear: 2011\\n\\nAbstract: In this paper, we propose an efficient and robust fall detection system by using a fuzzy one class support vector machine based on video in formation. Two cameras are used to capture the video frames from which the features are extracted. A fuzzy one class support vector machine (FOCSVM) is used to distinguish falling from other activities, such as walking, sitting, standing, bending or lying. Compared with the traditional one class support vector machine, the FOCSVM can obtain a more accurate and tight decision boundary under a training dataset with outliers. From real video sequences, the success of the method is confirmed with less non-fall samples being misclassified as falls by the classifier under an imperfect training dataset.\",\n \"Title: D-type anticipatory iterative learning control for a class of inhomogeneous heat equations\\nYear: 2013\\n\\nAbstract: In this paper, a D-type anticipatory iterative learning control (ILC) scheme is applied to the boundary control of a class of inhomogeneous heat equations, where the heat flux at one side is the control input while the temperature measurement at the other side is the control output. By transforming the inhomogeneous heat equation into its integral form and exploiting the properties of the embedded Jacobi Theta functions, the learning convergence of ILC is guaranteed through rigorous analysis, without any simplification or discretization of the 3D dynamics in the time, space as well as iteration domains. The adopted ILC scheme makes full use of the process repetition and deals with state-independent or state-dependent uncertainties. Meanwhile, due to the feedforward characteristic of ILC, the proposed scheme not only makes anticipatory compensation possible to overcome the heat conduction delay in boundary output tracking, but also eliminates the gain margin limitation encountered in feedback control. In the end, an illustrative example is presented to demonstrate the performance of the proposed ILC scheme.\",\n \"Title: Hypervisor-based protection of sensitive files in a compromised system\\nYear: 2012\\n\\nAbstract: One of the most fundamental issues in computer security is protecting sensitive files from unauthorized access. Traditional file protection tools run inside the target operating system, which hosts sensitive files. This makes previous approaches vulnerable in face of a compromised OS. To address this limitation, recent approaches seek for a good isolation by putting file system into a dedicated virtual machine or by using a network file system. However, they suffer a sharp increase in trusted computing base size which degrades their reliability. In this paper, we present Filesafe, a special purpose hy-pervisor aimed at protecting sensitive files in a compromised operating system. It bridges the semantic gap between guest OS and hypervisor by reconstructing file hierarchy from raw data, which incurs no runtime overhead. By enforcing security policies created in hypervisor, Filesafe could prevent sensitive files from unauthorized access even if they have kernel privileges in guest OS. We have implemented a proof-of-concept prototype on Windows XP with FAT32 file system. Furthermore, we evaluate Filesafe's performance and code size to demonstrate it is practical in real world scenarios.\",\n \"Title: Enhanced Privilege Separation for Commodity Software on Virtualized Platform\\nYear: 2010\\n\\nAbstract: Conventional privilege separation can effectively reduce the TCB size by granting privilege to only the privileged compartments. However, since they this approach relies on process isolation to ensure security assurance, malware exploiting against kernel components can easily compromise. Meanwhile, the frequent inter-process communications between separated processes inevitably incur notable overhead. To ameliorate these problems, we propose to perform privilege separation without partitioning application into two processes. Instead, we leverage virtualization to enforce the isolation of sensitive portions from other untrusted code. The virtual machine monitor intercepts all the code context switches transparently without requiring the application to explicitly use IPC as privilege context transition. We have implemented a prototype of our system, named Coir, based on commodity hypervisor Xen. Evaluation of our prototype includes a real-world remote control application, which is partitioned and protected in Coir-enabled hypervisor on unmodified Windows XP. We discuss the isolation strength as well as the performance penalty of our system based on the practical case.\",\n \"Title: Mobility Resistant Clustering in Multi-Hop Wireless Networks\\nYear: 2006\\n\\nAbstract: This paper presents a Distributed Efficient Clustering Approach (DECA) for mobility-resistant and energy-efficient clustering in multi-hop wireless networks. The clusterheads cover the whole network and each node in the network can exclusively determine the single cluster it belongs. DECA is fully distributed, each node transmits only one message during clustering operation, and the algorithm terminates in deterministic time without iterations. Theoretical results show the correctness of DECA, and extensive simulation results demonstrate that DECA is energy-efficient and robust against node mobility.\",\n \"Title: Study On Dynamic Variation Regularities Of Regional Groundwater Depth Based On Complexity Diagnosis\\nYear: 2011\\n\\nAbstract: In the course of analyzing and forecasting regional groundwater depth, its variation process complexity was ignored in the past, so that it was difficult to realize scientific management of groundwater resources. Aiming at the aforesaid defect, taking Jiansanjiang branch bureau as research platform, this paper diagnosed the complexity of each monthly groundwater depth series through using complexity measurement methods which include wavelet theory, fractal theory, Approximate Entropy and so on. The comprehensive measurement analysis results show that the complexity order of monthly groundwater depth series in the eighth district of Farm Nongjiang is highest in four farms of northern region. On that basis, the most complexity groundwater depth series combination stochastic forecasting model based on wavelet transform in northern region of Jiansanjiang branch bureau was set up. The model forecasting results show that local annual mean groundwater depth will be in a state of fluctuant lifting, and have considerable gap in comparison to groundwater ideal depth in the future. So, local government should reinforce the scientific management of groundwater. The research achievements break through the traditional study paradigm of hydrological forecasting, provide a research mode for studying regional hydrologic process, and provide scientific evidence for sustainable utilizing regional groundwater resources.\",\n \"Title: A relativistic extension of the complex scaling method using oscillator basis functions\\nYear: 2010\\n\\nAbstract: We develop the complex scaling method within the relativistic framework by expanding the Dirac spinors in the complete set of eigensolutions of a harmonic oscillator potential, and present the theoretical formalism of describing the discrete bound and resonant states on the same footing. Based on a well established and frequently used model, we demonstrate the utility and applicability of the extended method and examine the stability of the results with respect to the variations of the parameters of the model. Satisfactory agreements are found for all the calculated results in comparison with some other calculations in references. Especially, the present calculation in the nonrelativistic limit gives a consistent result with that in the nonrelativistic calculation.\",\n \"Title: Investigating the pattern of syndrome based on the difference of symptom network in depression\\nYear: 2013\\n\\nAbstract: In TCM theory, the syndrome is crucial to diagnose diseases and treat patients. In syndrome identification, the relation of symptoms usually correlates with syndrome and represents the pattern of syndrome at symptomatic level. Hence, we learn models for classifying syndromes in depression using 4 different algorithms, which are naive Bayes, Bayes network, SVM and C4.5. From the results of classification, we find that the dependence of symptoms has something to do with the accuracies of syndrome classification. Then, 8 symptom networks corresponding to depression and 7 syndromes are constructed to explore the interaction profile of symptoms under syndrome. By comparing syndrome-specific symptom network to the base network of depression, we discover the enriched edges and different nodes to represent the pattern of each syndrome. Literature and symptom ranking by Fisher score demonstrate the correctness of the different nodes selected through network comparison. After all, the enriched edges and different nodes associated with a given syndrome reveal the pattern of that syndrome at symptomatic level.\",\n \"Title: Output feedback adaptive iterative learning control for nonlinear discrete-time systems with unknown control directions\\nYear: 2012\\n\\nAbstract: An adaptive iterative learning control method is developed for a class of high-order nonlinear output feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. The n-step ahead predictor approach is employed to estimate the future outputs. The discrete Nussbaum gain method is incorporated into the control design to deal with the lack of a priori knowledge of the control directions. The proposed control algorithm guarantees that the tracking error converges to zero asymptotically along the iterative learning axis except for the beginning outputs affected by the random initial conditions with all the signals in the controlled system bounded. A numerical simulation is carried out to demonstrate the effectiveness of the proposed control laws.\",\n \"Title: Schedulability Analysis for Distributed Systems Using Network of Action Automata and Environment Automata\\nYear: 2011\\n\\nAbstract: Recently, several formal approaches have been presented to address the problem of schedulability analysis of real-time systems by some varieties of timed automata, e.g., UPPAAL and TIMES. In this paper, we consider a more general and complicated formal computational model for distributed systems. To analyze the schedulability of tasks within this model by automata theory, we present a model, action automata, which is a class of suspension automata, to describe the execution semantics of tasks, we also define an environment model, environment automata, to describe the arrival patterns of tasks. One main result gives the scheduling policies under which the schedulability can be analyzed by our method correctly. To achieve this result, we translate the schedulability analysis to the reach ability analysis of the network of action automata and environment automata. Therefore, another main result of this paper is that we prove the reach ability of action automata is decidable. Based on these conclusions, we implement a prototype tool for schedulability analysis and test its performance under EDF policy.\",\n \"Title: Logic switching based online periodic adaptive learning control algorithm dealing with unknown period and bound of the uncertain parameter\\nYear: 2013\\n\\nAbstract: In this paper, a switching periodic adaptive control approach is proposed for a class of nonlinear systems with periodic parametric uncertainties whose period and bound are not known. A fully saturated periodic adaptation law is utilized to estimate the unknown parameter vector. A logic switching based algorithm is provided to tune the unknown period and bound of the parameter vector online. By virtue of Lyapunov energy function, asymptotic convergence can be ensured for the tracking error and all the signals in the system is guaranteed bounded. A simulation to a one-link robotic manipulator is carried out to demonstrate the effectiveness of the switching learning control algorithm.\",\n \"Title: SPAD: Software Protection Through Anti-Debugging Using Hardware-Assisted Virtualization.\\nYear: 2012\\n\\nAbstract: Debugging usually facilitates the dynamic analysis of runtime application for software development. Yet it can also be a threat to system security when adopted by malicious attackers, and hence anti-debugging becomes valuable. The major challenges of software-only anti-debugging are the compromised strategy and lack of self-protection. This paper proposes software protection through anti-debugging (SPAD), a technique that imperceptibly monitors the behavior of debuggers. Leveraging hardware virtualization, SPAD detects debugging behavior by intercepting debug events on a higher privilege level than the conventional kernel space. Our experiment shows that SPAD can effectively prohibit the debugging behavior from 8 popular debuggers while the overhead incurred is 1.14%.\",\n \"Title: A digital authentication watermarking scheme for JPEG images with superior localization and security\\nYear: 2007\\n\\nAbstract: The drawbacks of the current authentication watermarking schemes for JPEG images, which are inferior localization and the\\n security flaws, are firstly analyzed in this paper. Then, two counterferiting attacks are conducted on them. To overcome these\\n drawbacks, a new digital authentication watermarking scheme for JPEG images with superior localization and security is proposed.\\n Moreover, the probabilities of tamper detection and false detection are deduced under region tampering and collage attack\\n separately. For each image block, the proposed scheme keeps four middle frequency points fixed to embed the watermark, and\\n utilizes the rest of the DCT coefficients to generate 4 bits of watermark information. During the embedding process, each\\n watermark bit is embedded in another image block that is selected by its corresponding secret key. Since four blocks are randomly\\n selected for the watermark embedding of each block, the non-deterministic dependence among the image blocks is established\\n so as to resist collage attack completely. At the receiver, according to judging of the extracted 4 bits of watermark information\\n and the corresponding 9-neighbourhood system, the proposed scheme could discriminate whether the image block is tampered or\\n not. Owing to the diminishing of false detection and the holding of tamper detection, we improve the accuracy of localization\\n in the authentication process. Theoretic analysis and simulation results have proved that the proposed algorithm not only\\n has superior localization, but also enhances the systematic security obviously.\",\n \"Title: Research on Vehicle Magneto-rheological Suspensions Vibration Control and Test\\nYear: 2006\\n\\nAbstract: A vehicle with independent magneto-rheological (MR) suspensions is regarded as a fleetly moving robot. To decrease MR suspension model simplification errors and to enhance the effect of MR suspension complicated vibration control, a hierarchical intelligent control (HIC) system is proposed. There are four independent local adaptive fuzzy (AF) controllers in control level and one coordination controller in coordination level. To restrain vibration of vehicle sprung mass and un-sprung mass, at the control level, a semi-active AF controller is designed for each MR suspension system, which can online adjust quantization factors and scale factor of fuzzy controller by human-simulation intelligent parameter modifying algorithm. At the coordination level, a controller is designed to coordinate the four local independent AF controllers, by adjusting their output parameters according to vehicle running attitude and characteristics of MR suspensions in different conditions. To validate the real results of hierarchical control, a MR suspension control and test system is set up and implemented on a mini automotive vehicle, which is equipped with four controllable MR dampers. Road tests under various conditions indicate that the HIC system can effectively reduce vertical vibration, improve the ride comfort, handle stability of vehicle, and show adaptiveness and robustness.\",\n \"Title: An anti-jamming framework of spread spectrum communications with ICA\\nYear: 2012\\n\\nAbstract: When jamming signal is strong enough, the performance of spread spectrum (SS) communications will decline quickly. According to the independence between the SS signal and the jamming signal in baseband, a novel anti-jamming framework of SS communication with independent component analysis (ICA) is proposed in this paper. This anti-jamming framework utilizes the particular structure of SS communications to reduce the degree of the received mixed signals. Because of the advantage of ICA, no prior knowledge of the jamming signal is needed any more, so the operations such as detection and parameter estimation of the jamming signal can be saved. The proposed anti-jamming framework deals with common jamming signals in a unifying framework, which needs not to switch among several anti-jamming techniques corresponding to different type of the jamming. The validity of the proposed method is proved by numerical simulation results at last.\",\n \"Title: Contactless RF MEMS switch using PZT actuation\\nYear: 2013\\n\\nAbstract: RF MEMS devices are competitive for handling high frequency microwave signals. In comparison to semiconductor devices, the performance of RF MEMS devices is highly linear, minimizing signal distortion. A contactless piezoelectric RF MEMS switch has been designed and simulated. Due to the use of a contactless design based on variable capacitance the reliability issues affecting contacting-type MEMS switches are avoided. The structure is piezoelectrically actuated using a sputtered lead zirconate titanate (PZT) layer. Finite element simulation has been conducted to optimize the structure. Electrical simulation predicts that, by achieving an on-off capacitance ratio greater than 10, isolation will exceed 15 dB over the frequency range from 4 to 15 GHz. Preliminary isolation measurements on fabricated devices without the actuating layer showed 26 dB isolation at 4 GHz, similar to that modeled, although isolation did not decrease by the modeled trend at high frequencies approaching 15 GHz. © 2013 IEEE.\",\n \"Title: Effect of RF sputtering parameters on PZT crystal growth\\nYear: 2013\\n\\nAbstract: Lead zirconate titanate(PZT) due to its large polarization, large dielectric constant and good piezoelectric performance has become popular in a wide range of applications in MEMS field. The prevailing technique for PZT deposition is sol-gel method, but the stability of solution and repeated coating can't be precisely controlled. Sputtering technique is used in this work for its relatively simple fabrication process, uniform thickness. In this work, PZT films are sputtered on Pt/Ti/SiO2/Si substrate prior to annealing. PZT preferential orientation is highly depend on the sputtering parameters. X-ray diffraction(XRD) analysis has been performed to compare the crystal growth. TiO2 seed layer is also introduced in this work.\",\n \"Title: A new magnetorheological elastomer isolator in shear - Compression mixed mode\\nYear: 2013\\n\\nAbstract: A new magnetorheological elastomer (MRE) isolator in shear-compression mixed mode is designed in this paper. Two pieces of MRE fabricated with different dimension are utilized in the isolator. The one MRE operates on compressive mode, and the other operates on shear mode. A finite element method magnetic (FEMM) package is used to analyze the magnetic circuit system, and a test system is established to obtain the vibration performance curves of MRE isolator. It is found that the natural frequency of MRE isolator changes greatly with variable current applied, and the amptitude of vibration is attenuated widely. Compared with the natural frequency of 0A, the increment of natural frequency is up to 103% with applied current reaches to 1.5A. The stiffness and damping coefficient of MRE isolator are identified by the experiment. The results show that the variable range of stiffness of MRE isolators with two operating modes is greater than that of single mode. © 2013 IEEE.\",\n \"Title: Research on role-network model for E-Government Affairs\\nYear: 2005\\n\\nAbstract: Constructing an E-Gov Affairs system requires complex systematic engineering, and it is difficult to be successful. Meanwhile, it is a very practical and independent action, and it is necessary to have a theoretic model suitable for an E-Gov Affairs environment. In this paper, based on the analysis of characteristics of E-Government Affairs, a role network model is proposed along with its relation to other relative models discussed. Finally, a formalization description of this model is given. © 2005 IEEE.\",\n \"Title: Modeling the commuting travel activities within historic districts in chinese cities\\nYear: 2014\\n\\nAbstract: The primary objective of this study is to analyze the characteristics of commuting activities within the historical districts in cities of China. The impacts of various explanatory variables on commuters' travels are evaluated using the structural equation modeling (SEM) approach. The household survey was conducted in the historical districts in Yangzhou, China. Based on the data, various individual and household attributes were considered exogenous variables, while the subsistence activity characteristics, travel times, numbers of three typical home-based trip chains, trip chains, and travel mode were considered as the endogenous variables. Commuters in our study were classified into two main groups according to their working location, which were the commuters in the historic district and those out of the district. The modeling results show that several individual and household attributes of commuters in historic district have significant impacts on the characteristics of travel activities. Additionally, the characteristics of travel activities within the two groups are quite different, and the contributing factors related to commuting travels are different as well.\",\n \"Title: A Virtualization Based Monitoring System for Mini-intrusive Live Forensics\\nYear: 2015\\n\\nAbstract: Digital evidences hold great significance for governing cybercrime. Unfortunately, previous acquisition tools were troubled by either the shortage of suspending the target system's running or the security of the acquisition tools themselves, thus the correctness and accuracy of their obtained evidences cannot be guaranteed. In this paper, we propose VAIL, a novel virtualization based monitoring system for mini-intrusive live forensics, which employs hardware assisted virtualization technique to gather integrated information from the native computer system. Meanwhile, the execution of the target system will not be interrupted and VAIL keeps immune to attacks from the target system. We have implemented a proof-of-concept prototype that has been validated with a Windows guest system. The experimental results show that VAIL can obtain comprehensive digital evidences from the target system as designed, including the CPU state, the physical memory content, and the I/O activities. And on average, VAIL only introduces 4.21 % performance overhead to the target system, which proves that VAIL is practical in real commercial environments.\",\n \"Title: An unsupervised acoustic fall detection system using source separation for sound interference suppression.\\nYear: 2015\\n\\nAbstract: We present a novel unsupervised fall detection system that employs the collected acoustic signals (footstep sound signals) from an elderly person׳s normal activities to construct a data description model to distinguish falls from non-falls. The measured acoustic signals are initially processed with a source separation (SS) technique to remove the possible interferences from other background sound sources. Mel-frequency cepstral coefficient (MFCC) features are next extracted from the processed signals and used to construct a data description model based on a one class support vector machine (OCSVM) method, which is finally applied to distinguish fall from non-fall sounds. Experiments on a recorded dataset confirm that our proposed fall detection system can achieve better performance, especially with high level of interference from other sound sources, as compared with existing single microphone based methods.\",\n \"Title: A Single-Channel Ica-R Method For Speech Signal Denoising Combining Emd And Wavelet\\nYear: 2014\\n\\nAbstract: According to the problem of speech signal denoising, we propose a novel method in this paper, which combines empirical mode decomposition (EMD), wavelet threshold denoising and independent component analysis with reference (ICA-R). Because there is only one mixed recording, it is a single-channel independent component analysis (SCICA) problem in fact, which is hard to solve by traditional ICA methods. EMD is exploited to expand the single-channel received signal into several intrinsic mode functions (IMFs) in advance, therefore traditional ICA of multi-dimension becomes applicable. First, the received signal is segmented to reduce the processing delay. Secondly, wavelet thresholding is applied to the noise-dominated IMFs. Finally, fast ICA-R is introduced to extract the object speech component from the processed IMFs, whose reference signal is constructed by assembling the high-order IMFs. The simulations are carried out under different noise levels and the performance of the proposed method is compared with EMD, wavelet thresholding, EMD-wavelet and EMD-ICA approaches. Simulation results indicate that the proposed method exhibit superior denoising performance especially when signal-to-noise ratio is low, with a half shorter running time.\",\n \"Title: vGASA: Adaptive Scheduling Algorithm of Virtualized GPU Resource in Cloud Gaming\\nYear: 2014\\n\\nAbstract: As the virtualization technology for GPUs matures, cloud gaming has become an emerging application among cloud services. In addition to the poor default mechanisms of GPU resource sharing, the performance of cloud games is inevitably undermined by various runtime uncertainties such as rendering complex game scenarios. The question of how to handle the runtime uncertainties for GPU resource sharing remains unanswered. To address this challenge, we propose vGASA, a virtualized GPU resource adaptive scheduling algorithm in cloud gaming. vGASA interposes scheduling algorithms in the graphics API of the operating system, and hence the host graphic driver or the guest operating system remains unmodified. To fulfill the service level agreement as well as maximize GPU usage, we propose three adaptive scheduling algorithms featuring feedback control that mitigates the impact of the runtime uncertainties on the system performance. The experimental results demonstrate that vGASA is able to maintain frames per second of various workloads at the desired level with the performance overhead limited to 5-12 percent.\",\n \"Title: Visualizing and analyzing dynamic meteorological data with virtual globes: A case study of tropical cyclones.\\nYear: 2015\\n\\nAbstract: Visualization is an important component of the evaluation of meteorological models, forecasting research, and other applications. With advances in computing power, the volume of meteorological data generated by geoscience and climate researchers has been steadily increasing. The emerging technique of virtual globes has been regarded as an ideal platform for visualizing larger geospatial data over the Internet. To visualize and analyze meteorological data with the new virtual globes, this paper proposes a systematic meteorological data visualization (MDV) framework in World Wind, an open-source virtual globe. The key technologies, including a hierarchical octree-based multiresolution data organization, data scheduling, level of detail (LOD) and rendering are described in detail. The framework is then applied to a practical tropical cyclone simulation, including flow vectors, particle tracking, cross-sectional analysis, streamlines, pathway animation, and volume rendering. The results show that virtual globes are effective tools for meteorological data visualization and analysis.\",\n \"Title: VGRIS: Virtualized GPU Resource Isolation and Scheduling in Cloud Gaming\\nYear: 2014\\n\\nAbstract: To achieve efficient resource management on a graphics processing unit (GPU), there is a demand to develop a framework for scheduling virtualized resources in cloud gaming. In this article, we propose VGRIS, a resource management framework for virtualized GPU resource isolation and scheduling in cloud gaming. A set of application programming interfaces (APIs) is provided so that a variety of scheduling algorithms can be implemented within the framework without modifying the framework itself. Three scheduling algorithms are implemented by the APIs within VGRIS. Experimental results show that VGRIS can effectively schedule GPU resources among various workloads.\",\n \"Title: Dancing with Giants: Wimpy Kernels for On-Demand I/O Isolation\\nYear: 2015\\n\\nAbstract: To be trustworthy, security-sensitive applications must be formally verified and hence small and simple, i.e., wimpy. Thus, they cannot include a variety of basic services available only in large and untrustworthy commodity systems, i.e., in giants. Hence, wimps must securely compose with giants to survive on commodity systems, i.e., rely on giants' services but only after efficiently verifying their results. This paper presents a security architecture based on a wimpy kernel that provides on-demand isolated I/O channels for wimp applications, without bloating the underlying trusted computing base. The size and complexity of the wimpy kernel are minimized by safely outsourcing I/O subsystem functions to an untrusted commodity operating system and exporting driver and I/O subsystem code to wimp applications. Using the USB subsystem as a case study, this paper illustrates the dramatic reduction of wimpy-kernel size and complexity, e.g., over 99% of the USB code base is removed. Performance measurements indicate that the wimpy-kernel architecture exhibits the desired execution efficiency.\",\n \"Title: Feedback nonlinear discrete-time systems\\nYear: 2014\\n\\nAbstract: In this paper, we design an adaptive iterative learning control method for a class of high-order nonlinear output feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. An n-step ahead predictor approach is employed to estimate future outputs. The discrete Nussbaum gain method is incorporated into the control design to deal with unknown control directions. The proposed control algorithm ensures that the tracking error converges to zero asymptotically along the iterative learning axis except for the beginning outputs affected by random initial conditions. A numerical simulation is carried out to demonstrate the efficacy of the presented control laws.\",\n \"Title: Direct heuristic dynamic programming method for power system stability enhancement\\nYear: 2014\\n\\nAbstract: In this paper a neural network-based approximate dynamic programming method, namely direct heuristic dynamic programming (direct HDP), is applied to power system stability control. Direct HDP is a learning and approximation based approach to address nonlinear system control under uncertainty. In the present paper, real-time system responses provided by wide area measurement system (WAMS) are used to construct such controllers which are uniquely tailored for the problems under consideration. In addition, the controller learning objective is formulated as a reward function that reflects global characteristics of the power system low frequency oscillation under the consideration of coupling effect among system components. The contribution of the paper includes a convergence proof of the direct HDP algorithm using an LQR framework, as well as case study to illustrate the proposed learning control algorithm. The case study aims at providing a new solution to a difficult large scale system coordination problem where the China Southern Power Grid is used for.\",\n \"Title: A novel ICA-based frequency hopping receiver with correlated jamming suppression\\nYear: 2012\\n\\nAbstract: Compared with common jamming techniques, the correlated jamming is much efficient against the frequency hopping (FH) communication system. Because of the similarity between the correlated jamming signal and the FH signal, it is very difficult for common anti-jamming techniques to deal with such correlated jamming. According to the independence between the payload of the correlated jamming signal and the victim FH signal, a novel independent component analysis (ICA) based receiver is proposed in this paper. Two antennas are introduced at the receiver end. The received signals are despread firstly to reduce the dimension of mixing matrix. Then ICA is utilized to recover the useful signal from two baseband signals. The numerical simulation results indicate that the proposed ICA-based receiver is robust to the correlated jamming. Even when the power of correlated jamming is very strong, the proposed receiver can still improve the BER performance greatly.\",\n \"Title: Detecting Bots in Follower Markets.\\nYear: 2014\\n\\nAbstract: Along with the widely using of microblog, third party services such as follower markets sell bots to customers to build fake influence and reputation. However, the bots and the customers that have large numbers of followers usually post spam messages such as promoted messages, messages containing malicious links. In this paper, we propose an effective approach for bots detection based on interaction graph model and BP neural network. We build an interaction graph model based on user interaction and design robust interaction-based features. We conduct a comprehensive set of experiments to evaluate the proposed features using different machine learning classifiers. The results of our evaluation experiments show that BP neural network classifier using our proposed features can be effectively used to detect bots compared to other existing state-of-the-art approaches.\",\n \"Title: Deep learning for posture analysis in fall detection\\nYear: 2014\\n\\nAbstract: We propose a novel computer vision based fall detection system using deep learning methods to analyse the postures in a smart home environment for detecting fall activities. Firstly, background subtraction is employed to extract the foreground human body. Then the binary human body images form the input to the classifier. Two deep learning approaches based on a Boltzmann machine and deep belief network are compared with a support vector machine approach. The final decision on the occurrence of a fall is made on the basis of combining the classifier output with certain contextual rules. Evaluations are performed on recordings from a real home care environment, in which 15 people create 2904 postures.\",\n \"Title: A dynamic prognosis algorithm in distributed fault tolerant model predictive control\\nYear: 2014\\n\\nAbstract: This paper presents a dynamic prognosis algorithm in distributed fault tolerant model predictive control (DFTMPC). The dynamic prognosis, which means predicting the trajectories of process variables under distributed model predictive control, is performed when a fault is diagnosed and several candidate reconfigured controls are proposed. Then, the dynamic prognosis is utilized to check whether the candidate reconfigured controls are able to drive the system to the new operating conditions and to evaluate the performance during the transition period. Thus, the most suitable candidate reconfigured controller is selected and its feasibility is ensured without using a Lyapunov function that is difficult to obtain for large-scale systems. On the other hand, the on-line computation burden of the prognosis algorithm is moderate under the assumption that the sets of active constraints in non-faulty subsystems remain the same as they are at the nominal operating conditions. Thus, the dynamic prognosis for DMPC is aimed to improve the applicability of the existing fault tolerant methods to large-scale systems.\",\n \"Title: A Multimodal Approach to Blind Source Separation of Moving Sources\\nYear: 2010\\n\\nAbstract: A novel multimodal approach is proposed to solve the problem of blind source separation (BSS) of moving sources. The challenge of BSS for moving sources is that the mixing filters are time varying; thus, the unmixing filters should also be time varying, which are difficult to calculate in real time. In the proposed approach, the visual modality is utilized to facilitate the separation for both stationary and moving sources. The movement of the sources is detected by a 3-D tracker based on video cameras. Positions and velocities of the sources are obtained from the 3-D tracker based on a Markov Chain Monte Carlo particle filter (MCMC-PF), which results in high sampling efficiency. The full BSS solution is formed by integrating a frequency domain blind source separation algorithm and beamforming: if the sources are identified as stationary for a certain minimum period, a frequency domain BSS algorithm is implemented with an initialization derived from the positions of the source signals. Once the sources are moving, a beamforming algorithm which requires no prior statistical knowledge is used to perform real time speech enhancement and provide separation of the sources. Experimental results confirm that by utilizing the visual modality, the proposed algorithm not only improves the performance of the BSS algorithm and mitigates the permutation problem for stationary sources, but also provides a good BSS performance for moving sources in a low reverberant environment.\",\n \"Title: Multimodal blind source separation for moving sources based on robust beamforming\\nYear: 2011\\n\\nAbstract: An improvement in the multimodal approach to the problem of blind source separation (BSS) of moving sources is proposed. The challenge of BSS for moving sources is that the mixing filters are time varying. Thus the unmixing filters should also be time varying, which are difficult to calculate from only statistical information avail able from limited number of audio samples. Therefore, in the pro posed approach a robust least square frequency invariant data independent (RLSFIDI) beamformer is implemented to perform real time speech enhancement and provide separation of the moving sources. Direction of arrival information of the sources is obtained from the visual 3-D tracker based on a Markov Chain Monte Carlo particle filter (MCMC-PF). The uncertainties in source localization and direction of arrival information are controlled by using convex optimization approach in the beamformer design. This provides robust ness with a wider main lobe for source of interest (SOI) and wider attenuation pattern to block the interference. In addition, white noise gain (WNG) constraint is used to control the beamformer sensitivity. Experimental results show that by utilizing RLSFIDI beamformer a significant improvement in BSS performance for moving sources is achieved in a low reverberant environment.\",\n \"Title: Graphics processing unit-based dynamic volume rendering for typhoons on a virtual globe.\\nYear: 2015\\n\\nAbstract: Typhoons are usually accompanied by strong winds, heavy rain, storm surges and other disastrous events, and they are the most severe weather phenomena in the western part of the North Pacific Ocean. Visualisation is a key technology for analysing and presenting climate simulations and observations together with related social and ecological data. Virtual globes are a logical platform for visualising such geospatial data via the Internet. To implement interactive visualisation of typhoon data within virtual globes, this study provides a 3D texture-mapping algorithm to render volume textures on a globe. In addition, a systematic framework is proposed in which a hierarchical octree-based multiresolution data structure is implemented to organise the large volume dataset, and a graphics processing unit-based dynamic interpolation approach is proposed to obtain a smooth effect. Finally, the structure is combined with a level of detail strategy to enable the rendering of dynamic volumetric data at an acceptable interactive frame rate. To demonstrate the capabilities of this framework, data for a simulated typhoon event were rendered in World Wind, an open-source virtual globe. The experimental results demonstrate that the application of the proposed strategies can result in an interactive visualisation performance that renders typhoon data on virtual globes.\",\n \"Title: Anomaly Detection in Microblogging via Co-Clustering.\\nYear: 2015\\n\\nAbstract: Traditional anomaly detection on microblogging mostly focuses on individual anomalous users or messages. Since anomalous users employ advanced intelligent means, the anomaly detection is greatly poor in performance. In this paper, we propose an innovative framework of anomaly detection based on bipartite graph and co-clustering. A bipartite graph between users and messages is built to model the homogeneous and heterogeneous interactions. The proposed co-clustering algorithm based on nonnegative matrix tri-factorization can detect anomalous users and messages simultaneously. The homogeneous relations modeled by the bipartite graph are used as constraints to improve the accuracy of the co-clustering algorithm. Experimental results show that the proposed scheme can detect individual and group anomalies with high accuracy on a Sina Weibo dataset.\",\n \"Title: Optimal Design Of A Multi-Server Queueing System With Delay Information\\nYear: 2016\\n\\nAbstract: Purpose - The purpose of this paper is to provide a framework for the optimal design of queueing systems of call centers with delay information. The main decisions in the design of such systems are the number of servers, the appropriate control to announce delay anticipated.Design/methodology/approach - This paper models a multi-server queueing system as an M/M/S + M queue with customer reactions. Based on customer psychology in waiting experiences, a number of different service-level definitions are structured and the explicit computation of their performance measures is performed. This paper characterizes the level of satisfaction with delay information to modulate customer reactions. Optimality is defined as the number of agents that maximize revenues net of staffing costs.Findings - Numerical studies show that the solutions to optimal design of staffing levels and delay information exhibit interesting differences, especially U-shaped curve for optimal staffing level. Experiments show how call center managers can determine economically optimal anticipated delay and number of servers so that they could control the trade-off between revenue loss and customer satisfaction.Originality/value - Many results that pertain to announcing delay information, customer reactions, and links to satisfaction with delay information have not been established in previous studies, however, this paper analytically characterizes these performance measures for staffing call centers.\",\n \"Title: Discrete-Time Adaptive Iterative Learning Control For High-Order Nonlinear Systems With Unknown Control Directions\\nYear: 2013\\n\\nAbstract: An adaptive iterative learning control method is proposed for a class of nonlinear strict-feedback discrete-time systems with random initial conditions and iteration-varying desired trajectories. An n-step ahead predictor approach is employed to estimate the future states in the control design. Discrete Nussbaum gain method is utilised to deal with the lack of a priori knowledge of control directions. The proposed control algorithm guarantees the boundedness of all the signals in the controlled system. The tracking error converges to zero asymptotically along the iterative learning axis except for beginning states affected by random initial conditions. The effectiveness of the proposed control scheme is verified through numerical simulation.\",\n \"Title: Determination of dominant weather parameters on reference evapotranspiration by path analysis theory\\nYear: 2016\\n\\nAbstract: •Path theory is a new valid method for selecting dominant factor affecting ET0.•ET0 could be accurately estimated by only two climate factors.•Sunshine duration has strongest effect on ET0.•Combination of path analysis and ANN has accuracy in ET0 estimation.•Only two stations’ ET0 estimation models can be universalized in South China.\",\n \"Title: The experimental study on vibration characteristics of MR seat suspension system\\nYear: 2013\\n\\nAbstract: Effects of damping coefficient and spring stiffness on the transfer characteristics of the seat suspension system is studied. Based on the designed magneto-rheological (MR) seat suspension, the vibration characteristic experiment system is set up. Considering the change of damping and stiffness of MR damper caused by current, the vibration characteristics experiment about the seat suspension system is made. The results show that increasing the input current can reduce the transmissibility of the seat suspension system before the 1st order resonance frequency, and it presents a strong controllability. Meanwhile, it verifies the correctness of the theoretical simulation from the point of the experiment. © 2013 IEEE.\",\n \"Title: A performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control\\nYear: 2015\\n\\nAbstract: This paper presents a performance optimization algorithm for controller reconfiguration in fault tolerant distributed model predictive control for large-scale systems. After the fault has been detected and diagnosed, several controller reconfigurations are proposed as candidate corrective actions for fault compensation. The solution of a set of constrained optimization problems with different actuator and setpoint reconfigurations is derived by means of an original approach, exploiting the information on the active constraints in the non-faulty subsystems. Thus, the global optimization problem is split into two optimization subproblems, which enable the online computational burden to be greatly reduced. Subsequently, the performances of different candidate controller reconfigurations are compared, and the better performing one is selected and then implemented to compensate the fault effects. Efficacy of the proposed approach has been shown by applying it to the benzene alkylation process, which is a benchmark process in distributed model predictive control. (C) 2015 Elsevier Ltd. All rights reserved.\",\n \"Title: A Robust student's-t distribution PHD filter with OCSVM updating for multiple human tracking\\nYear: 2015\\n\\nAbstract: We propose a novel robust probability hypothesis density (PHD) filter for multiple target. tracking in an enclosed environment, where a one-class support vector machine (OCSVM) is used in the update step for combining different human features to mitigate the effect of measurement noise on the calculation of particle weights. A Student's-t distribution is employed to improve the robustness of the filters whose tail is heavier than the Gaussian distribution and thus has the potential to cover more widely-spread particles. The OCSVM is trained based on both colour and oriented tzradient (HOG) histogram features and then used to mitigate the measurement noise from the particle selection step, thereby improve the tracking performance. To evaluate the proposed PHD filter, we employed two sequences from the CAVIAR dataset and used the optimal subpattern assignment (OSPA) method as an objective measure. The results show that the proposed robust PHD filter outperforms the traditional PHD filter.\",\n \"Title: Trusted Display on Untrusted Commodity Platforms\\nYear: 2015\\n\\nAbstract: A trusted display service assures the confidentiality and authenticity of content output by a security-sensitive application and thus prevents a compromised commodity operating system or application from surreptitiously reading or modifying the displayed output. Past approaches have failed to provide trusted display on commodity platforms that use modern graphics processing units (GPUs). For example, full GPU virtualization encourages the sharing of GPU address space with multiple virtual machines {\\\\\\\\em without} providing adequate hardware protection mechanisms; e.g., address-space separation and instruction execution control. This paper proposes a new trusted display service that has a minimal trusted code base and maintains full compatibility with commodity computing platforms. The service relies on a GPU separation kernel that (1) defines different types of GPU objects, (2) mediates access to security-sensitive objects, and (3) emulates object whenever required by commodity-platform compatibility. The separation kernel employs a new address-space separation mechanism that avoids the challenging problem of GPU instruction verification without adequate hardware support. The implementation of the trusted-display service has a code base that is two orders of magnitude smaller than other similar services, such as those based on full GPU virtualization. Performance measurements show that the trusted-display overhead added over and above that of the underlying trusted system is fairly modest.\",\n \"Title: Research of an improved algorithm for Chinese word segmentation dictionary based on double-array Trie-tree\\nYear: 2013\\n\\nAbstract: Chinese word segmentation dictionary based on the double-array Trie-tree has higher search efficiency,but the dynamic insertion consumes a lot of time.Therefore,an improved algorithm(iDAT)based on double-array Trie-tree for Chinese word segmentation dictionary is proposed.The nodes with more branches are handled while the original dictionary is being initialized.After the initialization,a Hash process is performed on the index values of empty sequence in base array.The final Hash table stores the sum of the empty sequences before the current empty sequence.After that,the iDAT is used to carry out the dynamic insertion process.This algorithm adopts Sunday jumps algorithm of single pattern matching.With the reasonable increasement of space,it reduces the the average time complexity of the dynamic insertion process in Trie-tree.Practical results show it has good operation performance.\",\n \"Title: SuperCall: A Secure Interface for Isolated Execution Environment to Dynamically Use External Services.\\nYear: 2015\\n\\nAbstract: Recent years have seen many virtualization-based Isolated Execution Environments (IEE) proposed in the literature to protect a Piece of Application Logic (PAL) against attacks from an untrusted guest kernel. A prerequisite of these IEE system is that the PAL is small and self-contained. Therefore, a PAL is deprived of channels to interact with the external execution environment including the kernel and application libraries. As a result, the PAL can only perform limited tasks such as memory-resident computation with inflexible utilization of system resources. To protect more sophisticated tasks, the application developer has to segment it into numerous PALs satisfying the IEE prerequisite, which inevitably lead to development inefficiency and more erroneous code. In this paper, we propose SuperCall, a new function call interface for a PAL to safely and efficiently call external untrusted code in both the kernel and user spaces. It not only allows flexible interactions between a PAL and untrusted environments, but also improved the utilization of resources, without compromising the security of the PAL. We have implemented SuperCall on top of a tiny hypervisor. To demonstrate and evaluate SuperCall, we use it to build a PAL as part of a password checking program. The experiment results show that SuperCall improves the development efficiency and incurs insignificant performance overhead.\",\n \"Title: An enhanced particle filtering method for GMTI radar tracking.\\nYear: 2016\\n\\nAbstract: This paper investigates the problem of ground vehicle tracking with ground-moving target indicator (GMTI) radar. In practice, the movement of ground vehicles may involve several different maneuvering types (acceleration, deceleration, standstill, etc.). Consequently, the GMTI radar may lose measurements when the radial velocity of the ground vehicle is below a threshold, i.e., falling into the Doppler blind region. In this paper, to incorporate the information gathered from normal measurements and knowledge on the Doppler blindness constraint, we develop an enhanced particle filtering method for which the importance distributions are inspired by a recent noise-related Doppler blind (NRDB) filtering algorithm for GMTI tracking. Specifically, when constructing the importance distributions, the proposed particle filter takes the advantages of the efficient NRDB algorithm by applying the extended Kalman filter and its generalization for interval-censored measurements. In addition, the linearization and Gaussian approximations in the NRDB algorithm are corrected by the weighting process of the developed filtering method to achieve a more accurate GMTI tracking performance. The simulation results show that the proposed method substantially outperforms the existing methods for the GMTI tracking problem.\",\n \"Title: New Multiple-Target Tracking Strategy Using Domain Knowledge and Optimization\\nYear: 2017\\n\\nAbstract: This paper proposes an environment-dependent vehicle dynamic modeling approach considering interactions between the noisy control input of a dynamic model and the environment in order to make best use of domain knowledge. Based on this modeling, a new domain knowledge-aided moving horizon estimation (DMHE) method is proposed for ground moving target tracking. The proposed method incorporates different types of domain knowledge in the estimation process considering both environmental physical constraints and interaction behaviors between targets and the environment. Furthermore, in order to deal with a data association ambiguity problem of multiple-target tracking in a cluttered environment, the DMHE is combined with a multiple-hypothesis tracking structure. Numerical simulation results show that the proposed DMHE-based method and its extension could achieve better performance than traditional tracking methods which utilize no domain knowledge or simple physical constraint information only.\",\n \"Title: Defect detection for patterned fabric images based on GHOG and low-rank decomposition.\\nYear: 2017\\n\\nAbstract: In contrast to defect-free fabric images with macro-homogeneous textures and regular patterns, the fabric images with the defect are characterized by the defect regions that are salient and sparse among the redundant background. Therefore, as an effective tool for separating an image into a redundant part (the background) and sparse part (the defect), the low-rank decomposition model provides an ideal solution for patterned fabric defect detection. In this paper, a novel patterned method for fabric defect detection is proposed based on a novel texture descriptor and the low-rank decomposition model. First, an efficient second-order orientation-aware descriptor, denoted as GHOG, is designed by combining Gabor and histogram of oriented gradient (HOG). In addition, a spatial pooling strategy based on human vision mechanism is utilized to further improve the discrimination ability of the proposed descriptor. The proposed texture descriptor can make the defect-free image blocks lay in a low-rank subspace, while the defective image blocks have deviated from this subspace. Then, a constructed low-rank decomposition model divides the feature matrix generated from all the image blocks into a low-rank part, which represents the defect-free background, and a sparse part, which represents sparse defects. In addition, a non-convex log det as a smooth surrogate function is utilized to improve the efficiency of the constructed low-rank model. Finally, the defects are localized by segmenting the saliency map generated by the sparse matrix. The qualitative results and quantitative evaluation results demonstrate that the proposed method improves the detection accuracy and self-adaptivity comparing with the state-of-the-art methods.\",\n \"Title: A Fiber-Optic Interferometric Tri-Component Geophone for Ocean Floor Seismic Monitoring.\\nYear: 2017\\n\\nAbstract: For the implementation of an all fiber observation network for submarine seismic monitoring, a tri-component geophone based on Michelson interferometry is proposed and tested. A compliant cylinder-based sensor head is analyzed with finite element method and tested. The operation frequency ranges from 2 Hz to 150 Hz for acceleration detection, employing a phase generated carrier demodulation scheme, with a responsivity above 50 dB re rad/g for the whole frequency range. The transverse suppression ratio is about 30 dB. The system noise at low frequency originated mainly from the 1/f fluctuation, with an average system noise level -123.55 dB re rad/root Hz ranging from 0 Hz to 500 Hz. The minimum detectable acceleration is about 2 ng/root Hz, and the dynamic range is above 116 dB.\",\n \"Title: Heterogeneous Sparse Relational Data Co-clustering in Social Network\\nYear: 2015\\n\\nAbstract: In social network, users generated multi-typed entities and complex interactive relations. The relational data mining is a hot research in social computing. Co-clustering algorithms have been proposed to mine underlying structure of different entities in heterogeneous social network. However, the real heterogeneous relational data are very sparse. In this paper, we propose a fast High-order Sparse Non-negative Matrix Factorization algorithm to co-cluster heterogeneous sparse relational data based on Correlation Matrix(HSNMF-CM), which is built by the correlation relations of small entities. In HSNMF-CM, the sparseness and size of matrix are reduced simultaneously. Under the sparse constraint, the block coordinate descent algorithms are used to accelerate the convergence rate of the matrix factorization. We assess the performance of the HSNMF-CM on two social data sets. The results show that our algorithm outperforms state-of-the-art algorithms on accuracy and convergence speed, and possesses a high scalability on large-scale heterogeneous relational data sets.\",\n \"Title: Model for evaluating the E-commerce logistics service quality with hesitant fuzzy uncertain linguistic information.\\nYear: 2017\\n\\nAbstract: In recent years, the electronic information and network technology has developed rapidly, meanwhile, E-commerce has been widely applied in society. Especially the online shopping, relying on its rich products, low price, no time and geographical restrictions and several other distinctive characteristics, which has absorbed attentions of many consumers. In recent years, China's online retail market has seen a big growth. The market share of e-commerce has gradually increased and become a mainstay of China's e-commerce development. However, with the fast growth of e-commerce, consumers' requirements for enterprise service quality is also getting higher and higher. Logistics services is considered to be one of the three main inhibitions of e-commerce and improve logistics service quality has gradually become an important way of e-commerce enterprises to obtain competitive advantage. At present, the research on how to evaluate the quality of e-commerce logistics services has not yet formed a complete and scientific theoretical system and method. In this paper, we have proposed the induced hesitant fuzzy uncertain linguistic Einstein correlated average (IHFULECA) operator. Then, we used the IHFULECA operator to design the multiple attribute decision making problems to estimate the E-commerce logistics service quality. At last, an example is given to shown the effectiveness of the proposed method.\",\n \"Title: Delay Announcements For Call Centers With Hyperexponential Patience Modeling\\nYear: 2017\\n\\nAbstract: Purpose - The purpose of this paper is to provide delay announcements for call centers with hyperexponential patience modeling. The paper aims to employ a state-dependent Markovian approximation for informing arriving customers about anticipated delay in a real call center.Design/methodology/approach - Motivated by real call center data, the patience distribution is modeled by the hyperexponential distribution and is analyzed by its realistic significance, with and without delay information. Appropriate M/M/s/r + H-2 queueing model is structured, including a voice response system that is employed in practice, and a state-dependent Markovian approximation is applied for computing abandonment. Based on this approximation, a method is proposed for estimating virtual delays, and it is investigated about the problem of announcing virtual delays to customers upon their arrival.Findings - There are two parts of findings from the results obtained from the case study and a numerical study of simulation comparisons. First, using an H-2 distribution for the abandonment distribution is driven by an empirical study which shows its good fit to real-life call center data. Second, simulation experiments indicate that the model and approximation are reasonable, and the state-dependent Markovian approximation works very well for call centers with larger pooling. It is concluded that our approach can be applied in a voice response system of real call centers.Originality/value - Many results pertain to announcing delay information, customer reactions and links to estimating hyperexponential distribution based on real data that have not been established in previous studies; however, this paper analytically characterizes these performance measures for delay announcements.\",\n \"Title: Robust Adaptive Iterative Learning Control for Discrete-Time Nonlinear Systems With Time-Iteration-Varying Parameters.\\nYear: 2017\\n\\nAbstract: In this paper, the robustness problem in adaptive iterative learning control for discrete-time nonlinear systems with time-iteration-varying parameters is investigated. The time-iteration-varying parameter can be expressed as the sum of an iteration-invariant time-varying part and a bounded iteration-drift term. Then a novel dead-zone method is applied in estimations of the iteration-invariant part and the drift bound simultaneously. The boundedness of tracking error is ensured by rigorous analysis. The efficacy of the proposed method is illustrated through simulation results.\",\n \"Title: Dynamic Graph Cuts in Parallel.\\nYear: 2017\\n\\nAbstract: This paper aims at bridging the two important trends in efficient graph cuts in the literature, the one is to decompose a graph into several smaller subgraphs to take the advantage of parallel computation, the other is to reuse the solution of the max-flow problem on a residual graph to boost the efficiency on another similar graph. Our proposed parallel dynamic graph cuts algorithm takes the adva...\",\n \"Title: Study on police graphic plotting technology based on web\\nYear: 2017\\n\\nAbstract: Graphic Plotting based on military use has been a hot issue in the aspect of real-time situation research. It plays a very important role in various military fields like operation command. In civil fields, especially in the public security industry, applications based on Police Graphic Symbol Standards starts late but progresses fast. With the maturing of its application in public secrity field, Graphic Plotting for Police needs to be further improved. This paper presents a way to express and transmit Police Graphic Plotting data with SVG technology, designs and develops a Police Graphic Symbol authoring tool and Graphic Symbol publishing software. The software has been verified to be a good solution to Graphic Plotting in public security field.\",\n \"Title: Exponential Synchronization for Second-Order Nodes in Complex Dynamical Network with Communication Time Delays and Switching Topologies\\nYear: 2017\\n\\nAbstract: This paper is devoted to the study of exponential synchronization problem for second-order nodes in dynamical network with time-varying communication delays and switching communication topologies. Firstly, a decomposition approach is employed to incorporate the nodes¿ inertial effects into the distributed control design. Secondly, the sufficient conditions are provided to guarantee the exponential synchronization of second-order nodes in the case that the information transmission is delayed and the communication topology is balanced and arbitrarily switched. Finally, to demonstrate the effectiveness of the proposed theoretical results, it is applied to the typical second-order nodes in dynamical network, as a case study. Simulation results indicate that the proposed method has a high performance in synchronization of such network.\",\n \"Title: Cross Domain Collaborative Filtering by Integrating User Latent Vectors of Auxiliary Domains.\\nYear: 2017\\n\\nAbstract: Cross-Domain Collaborative Filtering solves the sparsity problem by transferring rating knowledge across multiple domains. However, how to transfer knowledge from auxiliary domains is nontrivial. In this paper, we propose a model-based CDCF algorithm by Integrating User Latent Vectors of auxiliary domains (CDCFIULV) from the perspective of classification. For a user-item interaction in the target domain, we first use the trivial location information as the feature vector, and use the rating information as the label. Thus we can convert the recommendation problem into a classification problem. However, such a two-dimensional feature vector is not sufficient to discriminate the different rating classes. Hence, we require some other features for the classification problem with the help of the rating information from the auxiliary domains. In this paper, we assume the auxiliary domains contain dense rating data and share the same aligned users with the target domain. In this scenario, we employ UV decomposition model to obtain the user latent vectors from the auxiliary domains. We expand the trivial location feature vector in the target domain with the obtained user latent vectors from all the auxiliary domains. Thus we can effectively add features for the classification problem. Finally, we can train a classifier for this classification problem and predict the missing ratings for the recommender system. Hence the hidden knowledge in the auxiliary domains can be transferred to the target domain effectively via the user latent vectors. A major advantage of the CDCFIULV model over previous collective matrix factorization or tensor factorization models is that our model can adaptively select significant features during the training process. However, the previous collective matrix factorization or tensor factorization models need to adjust the weights of the auxiliary domains according to the similarities between the auxiliary domains and the target domain. We conduct extensive experiments to show that the proposed algorithm is more effective than many state-of-the-art single domain and cross domain CF methods.\",\n \"Title: Modelling and Analysis of the Cerebrospinal Fluid Flow in the Spinal Cord.\\nYear: 2017\\n\\nAbstract: The cerebrospinal fluid (CSF) flow in the spinal cord is important in maintaining the stability of the central nervous system. However, the interaction between CSF and spinal cord is not well understood. A three-dimensional (3D) simplified finite element model (FEM) of a sheep CSF and spinal cord segment was developed, verified using clinical experimental data, and used to investigate the effect of deformations and stress distributions on spinal cord in normal physiological conditions. The commercial software ANSYS Workbench was adopted to simulate the unidirectional CSF flow along the coaxial tube, which considered the bi-directional fluid-solid coupling. It was demonstrated that CSF had a slight impact on the spinal cord, which was transmitted to the white and gray matter through the pia mater. The pia mater protected the normal physiological function of the white and gray matter while the spinal dura mater ensured the regular rate and pressure of CSF. It was also showed that the CSF flow in the spinal cord was laminar. This model might help us to better understand the mechanism of interaction between CSF and spinal cord and provide a baseline for mechanical comparisons in spinal cord injury.\",\n \"Title: Computer vision based fall detection by a convolutional neural network.\\nYear: 2017\\n\\nAbstract: In this work, we propose a novel computer vision based fall detection system, which could be applied for the health-care of the elderly people community. For a recorded video stream, background subtraction is firstly applied to extract the human body silhouette. Extracted silhouettes corresponding to daily activities are applied to construct a convolutional neural network, which is applied for classification of different classes of human postures (e.g., bend, stand, lie and sit) and detection of a fall event (i.e., lying posture is detected in the floor region). As far as we know, this work is the first attempt for the application of the convolutional neural network for the fall detection application. From a dataset of daily activities recorded from multiple people, we show that the proposed method both achieves higher postures classification results than the state-of-the-art classifiers and can successfully detect the fall event with a low false alarm rate.\",\n \"Title: The optimization solutions method for customs risk with random dispatched model.\\nYear: 2017\\n\\nAbstract: In a market economy, it isn't an effective solution to the main contradiction of the Customs if simply relying on unlimited investment of management resources and the extensive extension of expansion-style management. Based on the need of solving this principal contradiction, the paper comprehensively reviews the concept and status of risk dispatched. We constructed a customs risk decision and performance evaluation of risk parameters management theoretical models. Also, we analyze the problems of customs risk management both from qualitative and quantitative aspects and make recommendations for the further optimization of risk management and surveillance.\",\n \"Title: A new self-tuning fuzzy controller for vibration of a flexible structure subjected to multi-frequency excitations.\\nYear: 2017\\n\\nAbstract: This work proposes a new self-tuning fuzzy controller for vibration control of a flexible structure subjected to both single-frequency and multi-frequency excitations. A piezoelectric stack actuator is used to generate control force to attenuate vibrations in the resonant and non-resonant frequency ranges. As a first step, modal frequencies and modal shapes of the flexible beam structure are obtained via the finite element method, and these are verified through comparison with the measured values. Second, in order to attenuate multi-frequency vibration of the beam, a new fuzzy controller with self-tuning factors is proposed. This controller is independent of the structure model and very adaptive to variable excitations. Then, vibration control performances of the self-tuning fuzzy controller are experimentally investigated under two different excitation conditions: single-frequency and multi-frequency excitations. It is shown that vibration control capability of the proposed controller outperforms conventional fuzzy controller under two different excitation conditions. In addition, it is demonstrated by experimentally implementing the proposed self-tuning fuzzy controller that high performances of multi-frequency vibration control are successfully achieved in which both amplitude and frequency of sinusoidal excitations are varied.\",\n \"Title: Wii: Device-Free Passive Identity Identification via WiFi Signals.\\nYear: 2017\\n\\nAbstract: Human behavior data is the basis of behavior analysis, and usually we need to collect large quantities of data before analysis. Most existing data collection methods are labor intensive works in which the volunteers need to be asked to behave naturally under the monitoring of researchers. Identity identification can be used in passive data collection of human behavior analysis systems in big data. Previous researches show the sensing potential of WiFi signals in a device-free passive manner. It is confirmed that human's gait is unique from each other like fingerprint and iris. As a result, researchers start to explore the ability of WiFi in human identification. However, the identification accuracy of existing approaches is not satisfactory in practice. In this paper, we present Wii, a device-free WiFi-based Identity Identification approach utilizing human's gait based on Channel State Information (CSI) of WiFi signals. Principle Component Analysis (PCA) and low pass filter are applied to remove the noises in the signals. We then extract entities' gait features from both time and frequency domain. Based on these features, Wii realizes identity identification through a Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel. It is implemented using commercial WiFi devices and evaluated in a typical indoor scenario. The results indicate that Wii achieves high identification accuracy with low computational cost and has the potential to work in human behavior analysis systems.\",\n \"Title: Impact of Emissions Trading System on Renewable Energy Output.\\nYear: 2017\\n\\nAbstract: In this paper, a cross-national panel is used to assess the impact of emissions trading system (ETS) on renewable energy output with a difference-in-difference design. From 2002 to 2013, several countries adopted ETS as a primary vehicle to drive carbon pollution reduction and boost the growth of renewables. By exploiting the cross-nation and cross-time variation in the timing of ETS, we find that ETS has materially improved renewable energy output, thereby indicating that the growth of the renewables has been successfully boosted through ETS. In addition, we examine the dynamics of the relationship between ETS and renewable energy output. Estimation result shows the ETS establishment has a trend effect on renewable energy output.\",\n \"Title: An Iteration-Varying Dead-Zone Based Robust Adaptive Ilc For Discrete-Time Nonlinear Systems With Uncertainties\\nYear: 2017\\n\\nAbstract: In this paper, we investigate the robust adaptive iterative learning control issue for discrete-time nonlinear systems with uncertainties by using an iteration-varying dead-zone approach. The uncertainties are dependent on both time index and iteration index, which can be expressed as the sum of a time-varying but iteration-invariant part and a bounded iteration-drift term. Then, a novel iteration-varying dead-zone approach is employed in the estimations of the iteration-invariant part and the drift bound simultaneously. The ultimate error bound is given explicitly with rigorous proof. Finally, simulation result has illustrated the efficacy of the proposed approach.\",\n \"Title: Adaptation and contextualization of deep neural network models.\\nYear: 2017\\n\\nAbstract: The ability of Deep Neural Networks (DNNs) to provide very high accuracy in classification and recognition problems makes them the major tool for developments in such problems. It is, however, known that DNNs are currently used in a ‘black box’ manner, lacking transparency and interpretability of their decision-making process. Moreover, DNNs should use prior information on data classes, or object categories, so as to provide efficient classification of new data, or objects, without forgetting their previous knowledge. In this paper, we propose a novel class of systems that are able to adapt and contextualize the structure of trained DNNs, providing ways for handling the above-mentioned problems. A hierarchical and distributed system memory is generated and used for this purpose. The main memory is composed of the trained DNN architecture for classification/prediction, i.e., its structure and weights, as well as of an extracted — equivalent — Clustered Representation Set (CRS) generated by the DNN during training at its final — before the output — hidden layer. The latter includes centroids — ‘points of attraction’ — which link the extracted representation to a specific area in the existing system memory. Drift detection, occurring, for example, in personalized data analysis, can be accomplished by comparing the distances of new data from the centroids, taking into account the intra-cluster distances. Moreover, using the generated CRS, the system is able to contextualize its decision-making process, when new data become available. A new public medical database on Parkinsonu0027s disease is used as testbed to illustrate the capabilities of the proposed architecture.\",\n \"Title: Method for Determining the Resonance Frequency of a Fiber Optic Interferometric Accelerometer.\\nYear: 2018\\n\\nAbstract: A novel measurement method for the resonance frequency of a fiber optic interferometric accelerometer, one of the most important technical parameters for such a sensor, is proposed and demonstrated. First, a variable phase shift is induced by a piezoelectric fiber stretcher which also serves to ascertain that the modulation depth is unchanged while maintaining the drive amplitude and increasing th...\",\n \"Title: Hierarchical control for parallel bidirectional power converters of a grid-connected DC microgrid.\\nYear: 2017\\n\\nAbstract: The DC microgrid is connected to the AC utility by parallel bidirectional power converters (BPCs) to import/export large power, whose control directly affects the performance of the grid-connected DC microgrid. Much work has focused on the hierarchical control of the DC, AC, and hybrid microgrids, but little has considered the hierarchical control of multiple parallel BPCs that directly connect the DC microgrid to the AC utility. In this paper, we propose a hierarchical control for parallel BPCs of a grid-connected DC microgrid. To suppress the potential zero-sequence circulating current in the AC side among the parallel BPCs and realize feedback linearization of the voltage control, a d-q-0 control scheme instead of a conventional d-q control scheme is proposed in the inner current loop, and the square of the DC voltage is adopted in the inner voltage loop. DC side droop control is applied to realize DC current sharing among multiple BPCs at the primary control level, and this induces DC bus voltage deviation. The quantified relationship between the current sharing error and DC voltage deviation is derived, indicating that there is a trade-off between the DC voltage deviation and current sharing error. To eliminate the current sharing error and DC voltage deviation simultaneously, slope-adjusting and voltage-shifting approaches are adopted at the secondary control level. The proposed tertiary control realizes precise active and reactive power exchange through parallel BPCs for economical operation. The proposed hierarchical control is applied for parallel BPCs of a grid-connected DC microgrid and can operate coordinately with the control for controllable/uncontrollable distributional generation. The effectiveness of the proposed control method is verified by corresponding simulation tests based on Matlab/Simulink, and the performance of the hierarchical control is evaluated for practical applications.\",\n \"Title: Discovering new PI3Kα inhibitors with a strategy of combining ligand-based and structure-based virtual screening.\\nYear: 2018\\n\\nAbstract: PI3Kα is a promising drug target for cancer chemotherapy. In this paper, we report a strategy of combing ligand-based and structure-based virtual screening to identify new PI3Kα inhibitors. First, naïve Bayesian (NB) learning models and a 3D-QSAR pharmacophore model were built based upon known PI3Kα inhibitors. Then, the SPECS library was screened by the best NB model. This resulted in virtual hits, which were validated by matching the structures against the pharmacophore models. The pharmacophore matched hits were then docked into PI3Kα crystal structures to form ligand-receptor complexes, which are further validated by the Glide-XP program to result in structural validated hits. The structural validated hits were examined by PI3Kα inhibitory assay. With this screening protocol, ten PI3Kα inhibitors with new scaffolds were discovered with IC values ranging 0.44-31.25 μM. The binding affinities for the most active compounds 33 and 74 were estimated through molecular dynamics simulations and MM-PBSA analyses.\",\n \"Title: Information Propagation Prediction Based on Key Users Authentication in Microblogging.\\nYear: 2018\\n\\nAbstract: In microblogging, key users are a significant factor for information propagation. Key users can affect information propagation size while retweeting the information. In this paper, to predict information propagation, we propose a novel linear model based on key users authentication. This model mines key users to dynamically improve the linear model while predicting information propagation. So our model can not only predict information propagation but also mine key users. Experimental results show that our model can achieve remarkable efficiency on predicting information propagation problem in real microblogging networks. At the same time, our model can find the key users who affect information propagation.\",\n \"Title: A Decentralized Coordination Control Method for Parallel Bidirectional Power Converters in a Hybrid AC-DC Microgrid.\\nYear: 2018\\n\\nAbstract: In the hybrid ac-dc microgrid, the ac and dc subgrids are connected by bidirectional power converters (BPCs) that play an important role in the load power sharing and power interaction between the ac and dc subgrids. The coordination control and circulating current suppression for the parallel BPC system are very challenging. In this paper, a decentralized coordination control method is proposed f...\",\n \"Title: Discrete-Time Switching Periodic Adaptive Control For Time-Varying Parameters With Unknown Periodicity\\nYear: 2018\\n\\nAbstract: In this paper, we address the problem of unknown periodicity for a class of discrete-time nonlinear parametric systems without assuming any growth conditions on the nonlinearities. The unknown periodicity hides in the parametric uncertainties, which is difficult to estimate with existing techniques. By incorporating a logic-based switching mechanism, we identify the period and bound of unknown parameter simultaneously. Lyapunov-based analysis is given to demonstrate that a finite number of switchings can guarantee the asymptotic tracking for the nonlinear parametric systems. The simulation result also shows the efficacy of the proposed switching periodic adaptive control approach.\",\n \"Title: A Novel Camera Based Approach For Automatic Expiry Date Detection And Recognition On Food Packages\\nYear: 2018\\n\\nAbstract: There is abundant of information on food packages, which include the food name, the expiry date and the ingredients. These information, especially the expiry date needs to be coded correctly before the products can be released into the market/supply chains. Failure of printing the correct expiry date can lead to both the health issues to the public and financial issues for recalling product back and even reimbursement. In this paper, we develop an automatic system that can achieve the expiry date region detection and recognition in an efficient and effective way. A deep neural network (DNN) based approach is firstly applied to find the expiry date region on the food package. The date characters are then extracted and recognized through the image processing and machine learning methods from the expiry date region. The system is the first camera based automatic system for recognizing expiry date on food packages. And the results tested on different types of food packages show that the system can achieve good performance on both detection and recognition of the expiry date.\",\n \"Title: Mathematical Performance Evaluation Model for Mobile Network Firewall Based on Queuing.\\nYear: 2018\\n\\nAbstract: While mobile networks provide many opportunities for people, they face security problems huge enough that a firewall is essential. The firewall in mobile networks offers a secure intranet through which all traffic is handled and processed. Furthermore, due to the limited resources in mobile networks, the firewall execution can impact the quality of communication between the intranet and the Internet. In this paper, a performance evaluation mathematical model for firewall system of mobile networks is developed using queuing theory for a multihierarchy firewall with multiple concurrent services. In addition, the throughput and the package loss rate are employed as performance evaluation indicators, and discrete-event simulated experiments are conducted for further verification. Lastly, experimental results are compared to theoretically obtained values to identify a resource allocation scheme that provides optimal firewall performance and can offer a better quality of service (QoS) in mobile networks.\",\n \"Title: PWiG: A Phase-based Wireless Gesture Recognition System\\nYear: 2018\\n\\nAbstract: With the development of the artificial intelligence, people hope that the advancement of the science and technology will continuously bring more convenience to their daily life. Therefore, gesture recognition has drawn more attentions. In the previous research, people paid their attentions on the aspect of the wearable devices and computer graphic. Although the recognition accuracy of previous methods is satisfactory under line-of-sight, the costs are very high and they require the users to be equipped with wearable sensors, which hinder their wide deployment. The development of wireless network provides convenience for solving this problem. Different gestures can be identified only according to the fluctuation of RSSI of wireless signals. But the intrinsic limitations of RSSI make it difficult to be feasible. Fortunately, CSI-based gesture recognition systems overcome the shortcomings above. In this paper, we propose a Phase-based Wireless Gesture recognition system PWiG, an accurate device-free gesture recognition approach. Compared with other existing gesture recognition systems, PWiG only needs commercial Wi-Fi devices to identify different gestures. PWiG uses the more sensitive phase information. Moreover, it reduces the hardware cost and greatly simplifies the process of the gesture extraction only by calculating the variance values. In addition, PWiG meets the standard of gesture recognition. According to the experimental results, PWiG achieves an average recognition accuracy of 94% in line-of-sight scenario and 89% in none-line-of-sight scenario.\",\n \"Title: Robust WLAN-Based Indoor Intrusion Detection Using PHY Layer Information.\\nYear: 2018\\n\\nAbstract: Intrusion detection techniques are widely used to guarantee the security of people's possessions. With the rapid development of wireless communication, device-free passive human detection based on wireless techniques may have more opportunities in intrusion detection. WiFi has been widely deployed in both public and private areas, which can be used as generalized sensors to detect human motion beyond communication. As a result, there have been several researches on WLAN-based motion detection. However, the detection accuracy of previous approaches declines significantly when people's moving speed becomes very slow. In this paper, we explore a novel method which has a relative stable detection performance under different moving speeds. We extract a novel feature representing the fluctuation of the whole channel from channel state information at the physical layer of 802.11n wireless networks, and utilize a probability technique to detect human motion. A hidden Markov model is leveraged as the classifier to make human detection a probability problem. We implement the system using off-the-shelf WiFi devices and evaluate it in two scenarios. As indicated in the evaluation results, our approach is an appropriate method for intrusion detection.\",\n \"Title: Fabric Defect Detection Based on Biological Vision Modeling.\\nYear: 2018\\n\\nAbstract: Fabric defect detection plays a key role in the quality control of textiles. Existing fabric defect detection methods adopt traditional pattern recognition methods; however, these methods lack adaptability and present poor detection performance. Because biological vision system has the ability to quickly locate salient objects, we propose a novel fabric defect detection algorithm based on biological vision modeling by simulating the mechanism of biological visual perception. First, a distinct, efficient, and robust feature descriptor from the biological modeling of P ganglion cells, which was proposed in our previous work, is adopted to improve the representation of fabric images with complex textures. To account for the low-rank and sparsity characteristics of biological vision, the low-rank representation (LRR) technique is adopted to model biological visual saliency, and it can decompose the fabric image into backgrounds and salient defect objects. Meanwhile, dictionary learning and Laplacian regularization are integrated into the LRR model as follows: 1) dictionary learning is used to denoise the saliency map; and 2) Laplacian regularization enlarges the gaps between defective regions and the background. Finally, the linearized accelerated direction method with adaptive penalty is adopted to solve the proposed model. The experimental results emphasize that the proposed algorithm has good detection performance for plain or twill fabrics with simple textures as well as for patterned fabrics with complex textures. Moreover, the proposed method is superior to the state-of-the-art methods in terms of its adaptability and detection efficiency.\",\n \"Title: Multiple Model Ballistic Missile Tracking With State-Dependent Transitions and Gaussian Particle Filtering.\\nYear: 2018\\n\\nAbstract: This paper proposes a new method for tracking the entire trajectory of a ballistic missile from launch to impact on the ground. Multiple state models are used to represent the different ballistic missile dynamics in three flight phases: boost, coast, and re-entry. In particular, the transition probabilities between state models are represented in a state-dependent way by utilizing domain knowledge...\",\n \"Title: Algorithm of Fuzzy Support Vector Machine based on a Piecewise Linear Fuzzy Weight Method\\nYear: 2018\\n\\nAbstract: AbstractThis article describes how fuzzy support vector machines FSVMs function well with good anti-noise performance, which receives the attention of many experts. However, the traditional center-distance fuzzy weight assignment method assigns support vectors with a small value of a membership degree and this weakens the role of support vectors in classification. In this article, a piecewise linear fuzzy weight computing method is proposed, in which boundary samples are assigned with a larger value of membership degree and samples far from the mean vector are assigned a smaller value of membership degree. The proposed method has a good classification performance, because the influence of noise samples is weakened and meanwhile the support vectors are paid much more attention. The experiments on the UCI database and MNIST data set fully verify the effectiveness of the proposed algorithm.\",\n \"Title: Research on the Complexity and Chaos Control about a Closed-Loop Supply Chain with Dual-Channel Recycling and Uncertain Consumer Perception.\\nYear: 2018\\n\\nAbstract: According to game theory, chaotic dynamics theory, and complexity based on the literature review about the pricing strategy and recycling channels of the closed-loop supply chain, on the background of the widespread hybrid recycling channels in Chinese electronic products market, this paper builds a closed-loop supply chain model with dual-channel recycling composed of one manufacturer and one third-party. We assume that the consumer perception towards the remanufacturing products is uncertain and limited. We carry on theoretical analysis of this model and perform numerical simulations from the perspective of entropy theory. Results show that a precipitous speed of recycling price adjustment of the manufacturer or the third-party will both lead the system into a chaotic state and cause the entropy of the system to increase. The system is sensitive to initial conditions in this chaotic condition. Focusing on the harmful effects of chaotic system, we introduce adjustment parameter to efficiently control the chaos. The results have a strong reference value to practical problems, so it has a great value in both theory and application.\",\n \"Title: Single-cell-trapping Microarrays with High Trapping Efficiency and Negligible Shear Stress\\nYear: 2018\\n\\nAbstract: In this study, two novel hydrodynamics-based radial microarrays are proposed to trap single cells with high trapping efficiency and negligible shear stress. Both microarrays are designed based on a single cell trapping microdevice we designed using a combination of the stagnation point flow and the boundary effect. For each microarray, the efficiency of trapping is evaluated with the flow velocity distribution in the microfluidic channel through two models: an initial model calculates the velocity distribution without cell trapping; in the contrary, a trapping model estimates the velocity distribution when a cell is trapped at the stagnation point. In both models, the flow velocity distribution is obtained using the computational fluid dynamics (CFD) package ANSYS 16.0. We conclude that both microarrays can capture single cells with high trapping success rate and negligible shear stress, which would be effective experimental platforms to study single cell behaviors in response to extracellular stimuli.\",\n \"Title: A Radial Microfluidic Array For Studying Single-Cell Ca2+ Dynamics Stimulated By Dynamic Atp Signals\\nYear: 2018\\n\\nAbstract: A radial microfluidic array is proposed to analyze intracellular calcium dynamics in response to dynamic extra-cellular adenosine triphosphate (ATP) stimulation at single cell level. The microfluidic array consists of multiple single cell trapping units in radial distribution with same angle, each unit is designed by a combination of stagnation point flow and physical barrier. Cellular experimental results verified that the effectiveness of the single cell trapping and intracellular calcium dynamic behaviors in response to static or dynamic extra-cellular ATP stimulation.\",\n \"Title: Bat-inspired hair sensor.\\nYear: 2016\\n\\nAbstract: We present the design of a directional airflow sensor inspired by the bat hair sensory system. The design is based on the integration of a MEMS structure with mechanical amplification of a deflecting hair on a suspended membrane together with differential sensing of parallel plate capacitors placed at the base of the hair. We describe the design and show simulations predicting that the structure is capable of detecting airspeeds of 0.5 m/sec in a directionally sensitive fashion. Furthermore, the structure is mechanically simple and inexpensive to fabricate. It has been integrated into a miniature form factor for deployment on the wing of a freely flying bat, and MEMS fabrication is currently underway.\",\n \"Title: Factors Affecting ENF Capture in Audio.\\nYear: 2019\\n\\nAbstract: The electric network frequency (ENF) signal is an environmental signature that can be captured in audiovisual recordings made in locations where there is electrical activity. This signal is influenced by the power grid in which the recording is made, and recent work has shown that it can be useful toward a number of forensics and security applications. An under-studied area of ENF research is the ...\",\n \"Title: Composite Energy Function-Based Spatial Iterative Learning Control in Motion Systems.\\nYear: 2018\\n\\nAbstract: In this brief, a novel spatial iterative learning control (ILC) method is proposed for a class of high-order nonlinear motion systems in the presence of both parametric and nonparametric uncertainties. Since the system performs the tracking task iteratively in the spatial domain and the uncertainties are functions of spatial coordinates, the traditional ILC that updates the control signals in the ...\",\n \"Title: Logistics Terminal Distribution Mode and Path Optimization Based on Ant Colony Algorithm.\\nYear: 2018\\n\\nAbstract: In order to discuss the logistics distribution that directly affects the satisfaction of consumers for the entire online shopping activities, this article mainly studies the logistics terminal distribution mode and path optimization, and combined with the application of ant colony algorithm in the traveling salesman problem, analyses the basic principle and implementation process of ant colony algorithm. In addition, through reference to map and field research, we consider the route length and road conditions (slope and congestion) of the the regional distribution point, and collect and draw the geographic information surrounding area A. Moreover, some key parameters in ant colony algorithm in value are chosen, and with the collected information as a concrete example, MATLAB simulation is carried out for the logistics terminal distribution path optimization based on ant colony algorithm, and its scientific nature and feasibility are verified. The simulation results showed that the ant colony algorithm has good feasibility so that it can be widely applied. As a result, it is concluded that the application of ant colony algorithm has great significance in the exploration of the logistics terminal distribution path optimization.\",\n \"Title: Decentralized Coordination Control For Parallel Bidirectional Power Converters In A Grid-Connected Dc Microgrid\\nYear: 2018\\n\\nAbstract: In the grid-connected mode, the dc microgrid is connected to the utility by parallel bidirectional power converters (BPCs), which provide voltage support for the dc microgrid. The coordination control for these parallel BPCs is very challenging. First, for the parallel BPCs, there is circulating current among them, which limits the total system capacity and may damage switching devices. Second, taking the constant power load into consideration, the performance especially the stability of the dc microgrid is degraded if the conventional i(dc)-v(dc) droop is adopted to share the power. Third, the voltage restoration should be faster for the better quality of dc voltage, and the restoration strategy should be scalable to the changes of the de microgrid topology for the better flexibility. For these problems, this paper proposes a decentralized control method for the parallel BPCs, which can make the BPCs operate in coordination and provide voltage support for the de microgrid well. Furthermore, the reliability of the proposed control method is illustrated by the stability analysis. All the conclusions are verified by the real-time hardware-in-loop tests.\",\n \"Title: Management of expressway service area based on integrated optimization.\\nYear: 2018\\n\\nAbstract: In view of the imperfect construction and the widespread loss on domestic expressway service areas, simply relying on the capital and human resources investment cannot improve the economic benefits efficiently. The M-Expressway service area is one of the most representative service areas in the Shanghai-Nanjing region. In this optimization project, we optimized the main revenue item and allocated parking spaces based on profit contributions, finally optimized the parking layout. With profit as the core, we linked the scattered business in the service area and achieved the goal of sequential optimization and overall optimization.\",\n \"Title: Comparison of advantages and disadvantages among various algorithms in logistics path design - Taking H-group as an example.\\nYear: 2018\\n\\nAbstract: There are many kinds of VRP problems and there are many ways to solve them. In this paper, we use ant colony algorithm, genetic algorithm, and annealing algorithm to optimize the selection of the logistics path of H-group located at He Nan Province. It establishes an algorithm evaluation system, and analyzes the performance of the three algorithms in six dimensions from qualitative and quantitative perspectives. Through MATLAB data calculation, we found that the ant colony algorithm performs equally well on the solution quality, solution efficiency, code storage, robustness, adaptability, and optimality.\",\n \"Title: KeggExp: a web server for visual integration of KEGG pathways and expression profile data.\\nYear: 2019\\n\\nAbstract: Effective visualization is important for knowledge discovery when analysing expression profile data. However, existing tools for visually integrating expression profile data with KEGG pathway maps lack extensive interactive visualization operations. KeggExp simultaneously presents the pathway map of one pathway, dendrogram and heatmap of the genes in the pathway and scatter map of one gene; and also provides interactive operations for highlighting specific genes on the pathway map, including differentially-expressed genes, co-expressed genes selected from the heatmap and user-input genes. With KeggExp, researchers, including those without programming skills, can take advantage of its interactive operations to determine key genes or pathways when analysing expression profile data. Availability and implementation: Freely available at http://www.fgvis.com/expressvis/KeggExp/. Language: JavaScript, python; Libraries: D3.js, Rxjs, Angular, Django, Django rest frame work, Scipy.\",\n \"Title: Spindle-Net: Cnns For Monocular Depth Inference With Dilation Kernel Method\\nYear: 2018\\n\\nAbstract: Learning depth from a single image is an important issue in computer vision. To solve this problem, encoder-decoder architect is usually employed as a powerful architecture to learn the dense corresponding function. In this work, we propose a symmetrical Spindle network of the encoder-decoder to learn the fine-grained depth. Unlike traditional convolution neural network, we first boost up the feature maps from low-dimension space to a high-dimension space, then extract the features for monocular depth learning. In order to overcome limitation of the computer memory, a single image super-resolution technique is proposed to replace the boosting process by fusing local cues in edge direction. Given the super-resolution images, the monocular depth learning needs more global information than most architectures for pixel-wise predictions. To address this issue, dilation kernel method is proposed to enlarge the receptive field in each layer. For the task of the super-resolution, the proposed method achieves better performance than the state-of-the-art methods. Extensive experiments on the monocular depth inference demonstrate that the Spindle network could achieve comparable performance on the NYU and Make3D datasets, compared with the state-of-the-art algorithms. The proposed method reveals a new perspective to learn the depth from a single image, which shows a promising generality to other pixel-wise prediction problems.\",\n \"Title: Global-optimization-based model decomposition for support-free multi-DOF 3D printing.\\nYear: 2018\\n\\nAbstract: In 3D printing, using supporting materials as few as possible is critical for efficiency and material saving. Although both model partition methods and 3D printers with multi-DOF(degree of freedom) have been developed independently to tackle the problem, only a few existing approaches combined partition methods with multi-DOF printers. We present a global-optimization-based model decomposition method for multi-DOF 3D printers to achieve consistent printing with the least supporting materials. We solve the minimization of the surface area that need supporting where the printing sequence is determined inherently by global single-objective optimization. We first describe the printing constraints for using a multi-DOF 3D printer, then propose an optimization framework that meets the constraints. Experiments show the merits of our method.\",\n \"Title: An approximation algorithm for vehicle routing with compatibility constraints.\\nYear: 2018\\n\\nAbstract: We study a multiple-vehicle routing problem with a minimum makespan objective and compatibility constraints. We provide an approximation algorithm and a nearly-matching hardness of approximation result. We also provide computational results on benchmark instances with diverse sizes showing that the proposed algorithm (i) has a good empirical approximation factor, (ii) runs in a short amount of time and (iii) produces solutions comparable to the best feasible solutions found by a direct integer program formulation.\",\n \"Title: ADRC-based Longitudinal Control for Novel Flight Vehicle with Moving Mass\\nYear: 2018\\n\\nAbstract: An adaptive longitudinal control law for moving mass control of a novel flight vehicle configuration is proposed. The coupling dynamic model between angle of attack and deflection of moving mass is generated. The dynamic analysis indicates that the proposed moving mass configuration with larger mass ratio gives rise to more dynamic coupling and maneuverability. Moreover, the control authority is determined by the mass ratio of the moving mass and the difference between the mass center of the moving mass and the mass center of the vehicle body. To deal with the coupling caused by the additional inertia moment of moving mass, the coupling dynamics system is transformed into a cascade system for controller design. Active disturbance rejection control framework is employed to design the adaptive longitudinal controller. Its extended state observer estimates the total disturbance to overcome the uncertainties in the flight vehicle model. The simulation results show that the proposed configuration is feasible and validate the quality of the adaptive controller which ensures good performance.\",\n \"Title: Design of Remote Fitting Platform Based on Virtual Clothing Sales\\nYear: 2022\\n\\nAbstract: To improve the convenience and effect of fitting process, an online fitting system of user-personalized body type based on the virtual technology is put forward. Firstly, it develops the fitting system with Java as the development language and constructs the human model, spinning motion model, and virtual clothing model; then, it divides the relevant model creation based on the body, generates the personalized body type, and designs the slab model, represented by triangular patch, while all points in same gender model keep the spatial position relation with each other to simplify the interpolation process; finally, it verifies the efficiency of the developed system through the factor analysis and cluster fitting design.\",\n \"Title: Characterization of Nucleobases in Broadband Terahertz Spectra from 0.5 to 10 THz with the Air-Biased-Coherent-Detection Technique.\\nYear: 2019\\n\\nAbstract: Terahertz time-domain spectroscopy (THz-TDS) is an effective coherent detection technique for deeply understanding the structures and functions of biomolecules. However, generally not full information in the whole THz range can be obtained due to the limited detection bandwidth (usually less than 5 THz) of the traditional THz-TDS systems. In this paper, effective THz absorption spectra in 0.5-10 THz range of five typical nucleobases of DNA/RNA are characterized with a super broadband THz detection technique, called the air-biased- coherent-detection (THz-ABCD) technique. Few unexpected characteristic absorption peaks appeared in the low-frequency region and meanwhile a series of anticipated characteristic absorption peaks are found in the high-frequency region. The fingerprint spectra of these nucleobases are helpful for further analysis on the vibration and twisting behavior of hydrogen bonds, van der Waals and electrostatic forces etc. between and within DNA/RNA biomolecules.\",\n \"Title: Aging, Urbanization, and Energy Intensity based on Cross-national Panel Data.\\nYear: 2017\\n\\nAbstract: On the basis of an unbalanced cross-national panel, this study employs the two-way fix-effects model to investigate the impact and effects of aging and urbanization on energy intensity. Estimation results show that aging has a negative effect on energy intensity, whereas urbanization has a positive effect on energy intensity. Empirical results also show that GDP per capita, overall productivity, and energy price have significant negative impacts on energy intensity. In addition, we find no empirical evidence of the general influence of foreign direct investment (FDI) on energy intensity. In the comparison of the classification of developed and developing countries, we further validate the previous results. Thus, this study provides a reference for governments in reducing energy intensity and improving governance.\",\n \"Title: Research on the system of smart city park based on cloud computing\\nYear: 2019\\n\\nAbstract: In order to effectively improve the management level and service level of the intelligent park, the information fusion in the intelligent park is studied. First, the main concepts of the Internet of things and cloud computing are discussed. It includes key technology, architecture, application field and key technology of cloud computing, platform architecture and so on. Based on the above, a hardware architecture and technical scheme based on cloud computing, cloud storage and cloud analysis is proposed. The design of the application system, the application support platform, the transmission and the sensors used in the park are discussed. In addition, a software architecture and technical scheme for information intelligent application system based on cloud computing, cloud storage and cloud analysis is proposed. The research target and function design of each application system are studied in detail. Finally, the implementation effect of intercommunication and fusion processing between the systems is analyzed. The results show that the system can effectively solve the information island phenomenon. The introduction of new technology will bring great social and economic benefits for the park. It provides a reference for the development of intelligent cities.\",\n \"Title: Research on intelligent city energy management based on Internet of things\\nYear: 2019\\n\\nAbstract: In order to solve the problem of energy management in Intelligent City, the energy management platform of the Internet of things is applied. the method of the energy consumption measurement data access to the energy management platform of the Internet of things is studied. According to the different communication protocols used by the energy management subsystem, the access methods of OPC technology, Web Service and open database connectivity and front-end communication are discussed. The results show that the intelligent city energy management system based on the Internet of things can meet the needs of the “intelligent city” construction. The system integrates the isolated energy information and realizes the energy consumption measurement. It lays the foundation for the diagnosis and energy saving evaluation of urban energy consumption.\",\n \"Title: Fluid models for call centers with delay announcement and retrials.\\nYear: 2018\\n\\nAbstract: This paper models a call center as a multi-server queue where anticipated delays are announced to customers upon arrival, and customer balking, reneging and retrials are modeled explicitly. The resulting queue with delay announcement is modeled in a stationary setting. We propose a fluid approximation to estimate the possibility of announcing the mean delay distribution and the retrials in the system. This approximation method can overcome some of the computational issues involved with a continuous time Markov chain analysis. The fluid approximation is also validated that it can work well in overloaded systems by performing a comparison between the fluid model and the stochastic model with delay information, and by performing the other comparison between the fluid model and the simulation model. Through a numerical study, this paper demonstrates the significance of delay information in a call center with retrials. In particular, delay announcement is more important in the system with a high retrial probability. Thus, we show how a delay announcement greatly reduces customer reneging and thereby improves customer satisfaction. It is shown that disregarding retrials in call centers with delay information may result in large distortions in the management of call centers.\",\n \"Title: An End-To-End Deep Neural Architecture For Optical Character Verification And Recognition In Retail Food Packaging\\nYear: 2018\\n\\nAbstract: There exist various types of information in retail food packages, including food product name, ingredients list and use by date. The correct recognition and coding of use by dates is especially critical in ensuring proper distribution of the product to the market and eliminating potential health risks caused by erroneous mislabelling. The latter can have a major negative effect on the health of consumers and consequently raise legal issues for suppliers. In this work, an end-to-end architecture, composed of a dual deep neural network based system is proposed for automatic recognition of use by dates in food package photos. The system includes: a Global level convolutional neural network (CNN) for high-level food package image quality evaluation (blurry/clear/missing use by date statistics); a Local level fully convolutional network (FCN) for use by date ROI localisation. Post ROI extraction, the date characters are then segmented and recognised. The proposed framework is the first to employ deep neural networks for end-to-end automatic use by date recognition in retail packaging photos. It is capable of achieving very good levels of performance on all the aforementioned tasks, despite the varied textual/pictorial content complexity found in food packaging design.\",\n \"Title: Using News To Predict Chinese Medicinal Material Price Index Movements\\nYear: 2018\\n\\nAbstract: Purpose The purpose of this paper is to propose an approach for predicting the movements of Chinese medicinal material price indexes using news based on text mining.Design/methodology/approach A research framework and three major methods, namely, domain dictionary construction, market convergence time calculation and dimensionality reduction integrating semantic analysis, are proposed for the approach. The proposed approach is applied in practice for predicting the price index movements of the top ten Chinese medicinal materials that receive the greatest media attention.Findings A set of experiments performed herein show that a predictive relationship exists between the news and the commodity market and that each of the three major methods improves the forecasting performance.Research limitations/implications Because the field of Chinese medicinal materials lacks a corpus that can be used for sentiment analysis, the accuracy of a trained automatic sentiment classifier is lower than obtained by a manual method, which can cause the calculated convergence result to be inaccurate, thus affecting the final prediction model. The manual method of having people label news decreases the proposed method's aspects of being intelligent and automatic.Practical implications Using the method proposed herein to predict the trends in Chinese medicinal materials prices helps farmers arrange a reasonable planting plan to pursue their best interests.Social implications The method proposed herein to predict the trends in the prices of Chinese medicinal materials is conducive to the government arranging planned drug availabilities in order to avoid disasters in which herbs are looted.Originality/value The produced prediction result is meaningful in supporting farmers and investors to make better decisions in growing and trading Chinese medicinal material, which leads to financial returns on investments and the avoidance of severe losses.\",\n \"Title: Nuclear norm-based recursive subspace prediction of time-varying continuous-time stochastic systems via distribution theory.\\nYear: 2018\\n\\nAbstract: •The random distribution theory is adopted to describe the time-derivative.•The method is generated by the ADMM and NNM, and extended to time-varying CT stochastic cases.•The prediction problem is solved by the rotation of the principal angle.\",\n \"Title: Identification Of Unknown Operating System Type Of Internet Of Things Terminal Device Based On Ripper\\nYear: 2018\\n\\nAbstract: Due to the vast popularity of sensors, cloud computing, mobile computing, and intelligent devices, the Internet of Things has seen tremendous growth in recent years. Operating system type recognition is the core technology of network security assessment. Due to inherit security problems of Internet of Things such as the situation of risk and threat of information, the operating system recognition seeks research attention for Internet of Things network security. In view of the current identification method of active operating system, it is prone to be detected by intrusion detection system. The operating system identification technology based on transmission control protocol/Internet protocol fingerprint library is more complicated than to distinguish the operating system types of unknown fingerprints. In this work, a passive operating system identification method based on RIPPER model is proposed. Also, it is compared with the existing support vector machine and C45 decision tree classification algorithms. Experiments reveal that RIPPER-based algorithm has better recognition accuracy and recognition efficiency.\",\n \"Title: Human-Object Contour for Action Recognition with Attentional Multi-modal Fusion Network\\nYear: 2019\\n\\nAbstract: Human action recognition has great research and application value in intelligent video surveillance, human-computer interaction and other communication fields. In order to improve the accuracy of human action recognition for video understanding, the extraction of human motion features and attentional fusion methods are studied. This paper has two main contributions. Firstly, based on the essence of optical flow validity, a novel dynamic feature expression method called Human-Object Contour(HOC) is presented, which combines object understanding and contextual information. Secondly, referring to the principle of Stacking in ensemble learning, we propose Attentional Multi-modal Fusion Network(AMFN). According to the characteristics of the video, attention is paid to selecting different modalities rather than simple averaging with fixed weight. The experiment shows that HOC is effectively complementary to the static appearance feature, and the accuracy of action recognition with our fusion network improves effectively. Our approach obtains the state-of-the-art performance on the datasets of HMDB51 (72.2%) and UCF101 (96.0%).\",\n \"Title: Stability Analysis of PV Generators With Consideration of P&O-Based Power Control\\nYear: 2019\\n\\nAbstract: Photovoltaic (PV) generators have continuously increased in recent years, whose power is usually controlled through the perturbation and observation (P&O) method. In essence, the P&O method is nonlinear and discontinuous. Hence, the conventional small-signal stability analysis is not suitable anymore when the influence of the P&O-based power control is considered. Focusing on this problem, this paper adopts the nonlinear describing function (DF) method to conduct the accurate stability analysis of PV generators with consideration of P&O-based power control. The detailed procedures about the DF method are introduced, and then the related influence factors like perturbation size, filters, and so on are analyzed quantitatively. Furthermore, the comparison with the conventional stability analysis methods is made, which suggests that the DF method can effectively enhance the accuracy of the stability analysis. All the conclusions are verified by the real-time hardware-in-loop tests.\",\n \"Title: Progressive Pose Attention Transfer For Person Image Generation\\nYear: 2019\\n\\nAbstract: This paper proposes a new generative adversarial network to the problem of pose transfer, i.e., transferring the pose of a given person to a target one. The generator of the network comprises a sequence of Pose-Attentional Transfer Blocks that each transfers certain regions it attends to, generating the person image progressively. Compared with those in previous works, our generated person images possess better appearance consistency and shape consistency with the input images, thus significantly more realistic-looking. The efficacy and efficiency of the proposed network are validated both qualitatively and quantitatively on Market-1501 and DeepFashion. Furthermore, the proposed architecture can generate training images for person re-identification, alleviating data insufficiency.\",\n \"Title: Exploiting Emotions for Fake News Detection on Social Media.\\nYear: 2019\\n\\nAbstract: Microblog has become a popular platform for people to post, share, and seek information due to its convenience and low cost. However, it also facilitates the generation and propagation of fake news, which could cause detrimental societal consequences. Detecting fake news on microblogs is important for societal good. Emotion is a significant indicator while verifying information on social media. Existing fake news detection studies utilize emotion mainly through users stances or simple statistical emotional features; and exploiting the emotion information from both news content and user comments is also limited. In the realistic scenarios, to impress the audience and spread extensively, the publishers typically either post a tweet with intense emotion which could easily resonate with the crowd, or post a controversial statement unemotionally but aim to evoke intense emotion among the users. Therefore, in this paper, we study the novel problem of exploiting emotion information for fake news detection. We propose a new Emotion-based Fake News Detection framework (EFN), which can i) learn content- and comment- emotion representations for publishers and users respectively; and ii) exploit content and social emotions simultaneously for fake news detection. Experimental results on real-world dataset demonstrate the effectiveness of the proposed framework.\",\n \"Title: Motion Standard Level System Based On Internet Of Things\\nYear: 2019\\n\\nAbstract: Recognition of motion level is a popular research area in the field of image processing in recent years. Based on the sensor equipment of action data acquisition, this article analyses the sensitivity of the micro-electro-mechanical system sensor. Then, according to the data-centric characteristics of the Internet of things, a distributed memory file storage and file writing system is constructed in the Internet of things environment, and the reliability and effectiveness of SensorFS are verified. Finally, dynamic time warping algorithm is used to evaluate the standard degree of human movement with dynamic time warping difference as experimental parameter, and a demonstration experiment of shadowboxing is designed to verify it. The result error is less than 0.05% by changing the standard of shadowboxing artificially, which proves the accuracy of the system. It provides a theoretical basis for the establishment of the standard system based on the Internet of things.\",\n \"Title: Announcing Delay Information to Improve Service in a Call Center with Repeat Customers\\nYear: 2019\\n\\nAbstract: We study the model of predicting and announcing delays, including customer satisfaction and repeat the behavior. In a call center, anticipated delays affect the customer behaviors of balking and reneging; we characterize the level of satisfaction with delay information to modulate customer reactions. In reality, a customer reacts by repeating behavior upon entering the service with a full perception of the delay. In particular, customers may feel dissatisfied when entering service because they have experienced a delay that is longer than announced. That is how satisfaction with delay information and waiting time affects customers' repeat behavior. Generally, customers may arrive at a higher rate when they are satisfied with the anticipated delay and the waiting experience in a call center. We characterize such performance measures using an M/M/S+M queue model. The revenue of a call center is generated by serving customers, and each time a customer abandons a call, the system loses revenue. Interestingly, the model reveals the revenue from the repeat behavior of satisfied customers. The formula used to approximate the arrival process reveals that traditional research could systematically underestimate the total number of call-ins and revenue. We show how call center managers can determine the most economically optimal anticipated delay so that they can control the trade-off between revenue loss and revenue from satisfaction.\",\n \"Title: Analysis and prediction of human acetylation using a cascade classifier based on support vector machine.\\nYear: 2019\\n\\nAbstract: Acetylation on lysine is a widespread post-translational modification which is reversible and plays a crucial role in some biological activities. To better understand the mechanism, it is necessary to identify acetylation sites in proteins accurately. Computational methods are popular because they are more convenient and faster than experimental methods. In this study, we proposed a new computational method to predict acetylation sites in human by combining sequence features and structural features including physicochemical property (PCP), position specific score matrix (PSSM), auto covariation (AC), residue composition (RC), secondary structure (SS) and accessible surface area (ASA), which can well characterize the information of acetylated lysine sites. Besides, a two-step feature selection was applied, which combined mRMR and IFS. It finally trained a cascade classifier based on SVM, which successfully solved the imbalance between positive samples and negative samples and covered all negative sample information. The performance of this method is measured with a specificity of 72.19% and a sensibility of 76.71% on independent dataset which shows that a cascade SVM classifier outperforms single SVM classifier. In addition to the analysis of experimental results, we also made a systematic and comprehensive analysis of the acetylation data.\",\n \"Title: A network security entity recognition method based on feature template and CNN-BiLSTM-CRF.\\nYear: 2019\\n\\nAbstract: By network security threat intelligence analysis based on a security knowledge graph (SKG), multi-source threat intelligence data can be analyzed in a fine-grained manner. This has received extensive attention. It is difficult for traditional named entity recognition methods to identify mixed security entities in Chinese and English in the field of network security, and there are difficulties in accurately identifying network security entities because of insufficient features extracted. In this paper, we propose a novel FT-CNN-BiLSTM-CRF security entity recognition method based on a neural network CNN-BiLSTM-CRF model combined with a feature template (FT). The feature template is used to extract local context features, and a neural network model is used to automatically extract character features and text global features. Experimental results showed that our method can achieve an F-score of 86% on a large-scale network security dataset and outperforms other methods.\",\n \"Title: Wide-Area Damping Control Of The Time Delay Power System Based On An E-Trade Off \\\"Damping-Time Delay\\\" Method\\nYear: 2018\\n\\nAbstract: With(1) the expansion of the scale of power system interconnection. The problem of low frequency oscillation of wide-area power system is more and more serious. Meanwhile, the transmission of wide-area signals will produce a time delay, and it can have great influence on the system stability. It is critically important to coordinate the relationship between the damping and the time delay, such that the power system remains stable. To achieve these objectives, we first construct, the reduced-order mathematical model of the power system. Then, a wide-area damping design method is developed based on an epsilon-tradeoff \\\"damping-time delay\\\". Using the linear matrix inequality toolbox and the Lyapunov stability criterion with time delay, parameters of the wide-area damping controller are obtained. Finally, we consider, as an example, a four -machine two-area model, and carry out simulations corresponding to different time delays using an iterative method. Simulation results show that WADC active power and rotor angle tend to be stable within 4 seconds. In addition, the damping stability of the power system is improved effectively compared with the control method based on common wide-area damping.\",\n \"Title: Self-Adaptive Microjet Array Cooling For Rf High Power Gan Integration On Silicon\\nYear: 2021\\n\\nAbstract: A novel Si interposer with microjet array cooling structure for RF high power GaN integration is presented in this work. The Si interposer is fabricated by stacking 3 wafers to form 2 layers of self-adaptive net microchannels and microjet array. The microfluids converge to form microjets in the bottom layer, then disperse in the top layer in 4 directions at net nodes. The cooling performance of the Si interposer is analyzed using finite element method (FEM) in COMSOL Multiphysics. The analysis results illustrate that the hotspot cooling capacity of the Si interposer depende largely on the flow rate of the coolant. The RF performance and temperature distribution of X-band GaN Monolithic Microwave Integrated Circuit (MMIC) power amplifier (PA) with static power density of similar to 480 W/cm(2) bonded on the Si interposer were measured in a test cube. The electrical measurement results validate that the cooling performance of the microjet impingement is able to provide the safety operating conditions of GaN MMIC PA. The thermal measurement results demonstrate that the hotspot cooling capacity of the Si interposer enabled GaN PA with hotspot heat density over 323.2 W/mm(2) to operate safely with low flow rate at 70 degrees C. The interposer is a promising solution for high power integration in silicon-based RF microsystem.\",\n \"Title: Closed-loop delta-operator-based subspace identification for continuous-time systems utilising the parity space\\nYear: 2021\\n\\nAbstract: This paper presents a closed-loop delta-operator-based subspace identification method for continuous-time systems utilising the parity space. The continuous-time systems are transformed to the delta-operator-based state space models which converge to the original systems with the sampling period going to zero. Instead of using the observable subspace, we focus on the parity space which is commonly employed in fault detection. The system is estimated consistently by the instrumental variable method and principal component analysis, which solves the identification problems of biased results as the system operates in closed-loop due to the feedback controller. The effectiveness of the proposed method is illustrated by simulation results.\",\n \"Title: Deep Learning Based Prediction On Greenhouse Crop Yield Combined Tcn And Rnn\\nYear: 2021\\n\\nAbstract: Currently, greenhouses are widely applied for plant growth, and environmental parameters can also be controlled in the modern greenhouse to guarantee the maximum crop yield. In order to optimally control greenhouses' environmental parameters, one indispensable requirement is to accurately predict crop yields based on given environmental parameter settings. In addition, crop yield forecasting in greenhouses plays an important role in greenhouse farming planning and management, which allows cultivators and farmers to utilize the yield prediction results to make knowledgeable management and financial decisions. It is thus important to accurately predict the crop yield in a greenhouse considering the benefits that can be brought by accurate greenhouse crop yield prediction. In this work, we have developed a new greenhouse crop yield prediction technique, by combining two state-of-the-arts networks for temporal sequence processing-temporal convolutional network (TCN) and recurrent neural network (RNN). Comprehensive evaluations of the proposed algorithm have been made on multiple datasets obtained from multiple real greenhouse sites for tomato growing. Based on a statistical analysis of the root mean square errors (RMSEs) between the predicted and actual crop yields, it is shown that the proposed approach achieves more accurate yield prediction performance than both traditional machine learning methods and other classical deep neural networks. Moreover, the experimental study also shows that the historical yield information is the most important factor for accurately predicting future crop yields.\",\n \"Title: Adaptive Relay Strategy Selection Based On Q-Learning For Power Line And Wireless Dual-Media Communication With Hybrid Duplex\\nYear: 2021\\n\\nAbstract: Relay algorithms in power line and wireless dual-media cooperative communication exhibit distinct advantages and disadvantages under random channels, and the algorithm that achieves the best performance can be determined through an adaptive relay strategy. However, the theoretical performance analysis of multiple relay algorithms for mixed fading and impulse noise encounters practical difficulties, such as lack of closed-form expressions and high complexity of the approximation process. This study proposes an adaptive relay strategy selection algorithm based on Q-learning, which can maximize the mutual information in the system. The feedback of the amount of mutual information is obtained by learning the dual-media cooperative communication environment of the time-varying fading channel to determine the optimal relay algorithm and power allocation factor. This study also analyzes the influence of the average signal-to-noise ratio, relay position, and power line channel parameters on the performance of the algorithm in terms of mutual information and outage probability and implements Q-learning-based relay strategy selection. Simulation results show that the proposed algorithm can obtain a quasi-optimal system performance in terms of the above two measures.\",\n \"Title: Online Testing of Subgroup Treatment Effects Based on Value Difference\\nYear: 2021\\n\\nAbstract: Online A/B testing plays a critical role in the high-tech industry to guide product development and accelerate innovation. It performs a null hypothesis statistical test to determine which variant is better. However, a typical A/B test presents two problems: (i) a fixed-horizon framework inflates the false-positive errors under continuous monitoring; (ii) the homogeneous effects assumption fails to identify a subgroup with a beneficial treatment effect. In this paper, we propose a sequential test for subgroup treatment effects based on value difference, named SUBTLE, to address these two problems simultaneously. The SUBTLE allows the experimenters to \\\"peek\\\" at the results during the experiment without harming the statistical guarantees. It assumes heterogeneous treatment effects and aims to test if some subgroup of the population will benefit from the investigative treatment. If the testing result indicates the existence of such a subgroup, a subgroup will be identified using a readily available estimated optimal treatment rule. We examine the empirical performance of our proposed test on both simulations and a real dataset. The results show that the SUBTLE has high detection power with controlled type I error at any time, is more robust to noise covariates, and can achieve early stopping compared with the corresponding fixed-horizon test.\",\n \"Title: Thresholds Of Key Disaster-Inducing Factors And Drought Simulation In The Xilinguole Grassland\\nYear: 2021\\n\\nAbstract: The frequency of extreme events such as droughts is increasing due to climate change. Grassland ecosystems are extremely sensitive to drought. This study aims to analyse how droughts respond to meteorological factors, establish a method to quantitatively evaluate the threshold values of key meteorological factors that can induce drought in different time periods, and explore a drought prediction model applicable to the Xilinguole Grassland. The Xilinguole Grassland has experienced an obvious aridification trend, with notable fluctuations in short dry and wet periods and the probability of drought (generally ranked in the order of moderate drought > light drought > severe drought > extreme drought). The Xilinguole Grassland is expected to face more intense drought conditions in the next 5 years. Among the meteorological elements, temperature, precipitation, water vapor pressure and solar radiation are the key factors influencing drought. Both short-term and long-term changes in precipitation and temperature have a strong influence on drought. Short-term changes in water vapor pressure have a significant impact on drought. Drought is sensitive to extreme climate events and is most sensitive to the influence of meteorological factors in May-September, particularly in July. In July, drought can be induced by any of the following: monthly precipitation below 50 mm, an average temperature above 23 degrees C, sunshine percentage above 69%, a monthly sunshine duration above 319 h, or an average water vapor pressure below 12 hPa. In addition, Markov chain modelling is a feasible approach for predicting drought in the Xilinguole Grassland. This study provides a scientific basis for drought prevention and control.\",\n \"Title: A Novel Computer Vision-Based Data Driven Modelling Approach For Person Specific Fall Detection\\nYear: 2021\\n\\nAbstract: In this paper, we propose a novel person specific fall detection system based on a monocular camera, which can be applied for assisting the independent living of an older adult living alone at home. A single camera covering the living area is used for video recordings of an elderly person's normal daily activities. From the recorded video data, the human silhouette regions in every frame are then extracted based on the codebook background subtraction technique. Low-dimensionality representative features of extracted silhouetted are then extracted by convolutional neural network-based autoencoder (CNN-AE). Features obtained from the CNN-AE are applied to construct an one class support vector machine (OCSVM) model, which is a data driven model based on the video recordings and can be applied for fall detection. From the comprehensive experimental evaluations on different people in a real home environment, it is shown that the proposed fall detection system can successfully detect different types of falls (falls towards different orientations at different positions in a real home environment) with small false alarms.\",\n \"Title: Current-constrained finite-time control algorithm for DC-DC Buck converter\\nYear: 2021\\n\\nAbstract: This paper studies the voltage regulation problem of Buck converter under current constraint. Firstly, to speed up the voltage regulation, a nonlinear algorithm is proposed to make the output voltage track the reference voltage quickly in a finite time. Meanwhile, to protect the devices in the circuit, the current-constraint problem is also considered in the finite-time controller design. In addition, the situation of load change is also considered. The proof of finite-time stability of the total closed-loop system is given and its validity is fully tested. Finally, simulation and experiment verify that the system has excellent dynamic performance and steady-state performance.\",\n \"Title: Logistics cost control in food processing enterprises based on TD-ABC\\nYear: 2021\\n\\nAbstract: In order to improve the logistics operation of food processing enterprises and control the logistics cost, this paper starts from the analysis of the logistics operation process and characteristics of enterprises, analyzes the logistics cost classification and composition of food processing enterprises, puts forward the basic process of applying TD-ABC to control the logistics cost, constructs the logistics cost accounting model of food processing enterprises based on TD-ABC, and puts forward relevant logistics cost control methods including the design of logistics cost control system, the determination of logistics cost control points and specific implementation steps. The typical food processing enterprises are selected for the empirical study of logistics cost accounting and controlling. By comparing the cost accounting results of TD-ABC and ABC, the result shows that TD-ABC (Time-Driven Activity-Based Costing) method can accurately grasp the logistics cost composition, identify inefficient logistics operations and non-value-added operations, and analyze the efficiency of various logistics departments, verify the feasibility and effectiveness of logistics cost accounting model and control method system, and provide some advice for logistics cost control and logistics process transformation of food processing enterprises.\",\n \"Title: Reproducible untargeted metabolomics workflow for exhaustive MS2 data acquisition of MS1 features\\nYear: 2022\\n\\nAbstract: Unknown features in untargeted metabolomics and non-targeted analysis (NTA) are identified using fragment ions from MS/MS spectra to predict the structures of the unknown compounds. The precursor ion selected for fragmentation is commonly performed using data dependent acquisition (DDA) strategies or following statistical analysis using targeted MS/MS approaches. However, the selected precursor ions from DDA only cover a biased subset of the peaks or features found in full scan data. In addition, different statistical analysis can select different precursor ions for MS/MS analysis, which make the post-hocvalidation of ions selected following a secondary analysis impossible for precursor ions selected by the original statistical method. Here we propose an automated, exhaustive, statistical model-free workflow: paired mass distance-dependent analysis (PMDDA), for reproducible untargeted mass spectrometry MS2 fragment ion collection of unknown compounds found in MS1 full scan. Our workflow first removes redundant peaks from MS1 data and then exports a list of precursor ions for pseudo-targeted MS/MS analysis on independent peaks. This workflow provides comprehensive coverage of MS2 collection on unknown compounds found in full scan analysis using a\\\"one peak for one compound\\\"workflow without a priori redundant peak information. We compared pseudo-spectra formation and the number of MS2 spectra linked to MS1 data using the PMDDA workflow to that obtained using CAMERA and RAMclustR algorithms. More annotated compounds, molecular networks, and unique MS/MS spectra were found using PMDDA compared with CAMERA and RAMCIustR. In addition, PMDDA can generate a preferred ion list for iterative DDA to enhance coverage of compounds when instruments support such functions. Finally, compounds with signals in both positive and negative modes can be identified by the PMDDA workflow, to further reduce redundancies. The whole workflow is fully reproducible as a docker image xcmsrocker with both the original data and the data processing template.\",\n \"Title: Optimized Algebraic Reconstruction Algorithm Based Hemodynamic Changes in Color Doppler Ultrasound in Monitoring the Patients with Colorectal Cancer Undergoing Peripherally Inserted Central Catheter and Catheterization Nursing\\nYear: 2021\\n\\nAbstract: The purpose of this study was to analyze the hemodynamic changes and nursing care of patients with colorectal cancer who were peripherally placed into the central venous catheter (PICC) by color Doppler ultrasound based on an optimized algebraic reconstruction (ART) (OART) algorithm. In this study, 150 patients with colorectal cancer were selected and randomly divided into observation group and control group, with 75 cases in each group. Different nursing interventions were carried out. An optimized algebraic reconstruction (OART) algorithm was proposed, and the traditional ART algorithm and filtered back-projection (FBP) algorithm were introduced for comparison. They were applied in ultrasounds of 150 colorectal cancer patients undergoing PICC. The results showed that the Dice coefficient (Dice) and peak signal-to-noise ratio (PSNR) of the OART algorithm were greater than those of the ART and FBP algorithms, while the difference function (DF) and the running time were opposite (P < 0.05). The blood flow velocity (BFV) and blood flow (BF) of the arm vein 5 days after puncture were the least, which were less than those before puncture and 10 days and 30 days after puncture (P < 0.05). Thrombosis was most likely to be found 4-6 days after puncture (28 cases), followed by 10-15 days after puncture (22 cases), and one day after the puncture (19 cases). The BFV and BF of patients with thrombosis were lower than those of patients without thrombosis (P < 0.05). The total infection rate of PICC in the observation group was 10.7%, which was lower than that in the control group 32.0%, P < 0.05. Nursing satisfaction of patients in observation group and control group was 95.99% and 75.99%, respectively, P < 0.05, and the difference was statistically significant. In short, the ORAT algorithm proposed had better performance than the traditional algorithms in ultrasound image reconstruction; strengthening nursing intervention for chemotherapy patients with colorectal cancer undergoing PICC could effectively reduce the infection rate of PICC and improve the nursing satisfaction of patients.\",\n \"Title: Improving Column Generation for Vehicle Routing Problems via Random Coloring and Parallelization\\nYear: 2022\\n\\nAbstract: We consider a variant of the vehicle routing problem (VRP) where each customer has a unit demand and the goal is to minimize the total cost of routing a fleet of capacitated vehicles from one or multiple depots to visit all customers. We propose two parallel algorithms to efficiently solve the column-generation-based linear-programming relaxation for this VRP. Specifically, we focus on algorithms for the \\\"pricing problem,\\\" which corresponds to the resource-constrained elementary shortest path problem. The first algorithm extends the pulse algorithm for which we derive a new bounding scheme on the maximum load of any route. The second algorithm is based on random coloring from parameterized complexity which can be also combined with other techniques in the literature for improving VRPs, including cutting planes and column enumeration. We conduct numerical studies using VRP benchmarks (with 50-957 nodes) and instances of a medical home care delivery problem using census data in Wayne County, Michigan. Using parallel computing, both pulse and random coloring can significantly improve column generation for solving the linear programming relaxations and we can obtain heuristic integer solutions with small optimality gaps. Combining random coloring with column enumeration, we can obtain improved integer solutions having less than 2% optimality gaps for most VRP benchmark instances and less than 1% optimality gaps for the medical home care delivery instances, both under a 30-minute computational time limit. The use of cutting planes (e.g., robust cuts) can further reduce optimality gaps on some hard instances, without much increase in the run time. Summary of Contribution: The vehicle routing problem (VRP) is a fundamental combinatorial problem, and its variants have been studied extensively in the literature of operations research and computer science. In this paper, we consider general-purpose algorithms for solving VRPs, including the column-generation approach for the linear programming relaxations of the integer programs of VRPs and the column-enumeration approach for seeking improved integer solutions. We revise the pulse algorithm and also propose a random-coloring algorithm that can be used for solving the elementary shortest path problem that formulates the pricing problem in the column-generation approach. We show that the parallel implementation of both algorithms can significantly improve the performance of column generation and the random coloring algorithm can improve the solution time and quality of the VRP integer solutions produced by the column-enumeration approach. We focus on algorithmic design for VRPs and conduct extensive computational tests to demonstrate the performance of various approaches.\",\n \"Title: Non-Intrusive Adaptive Load Identification Based on Siamese Network\\nYear: 2022\\n\\nAbstract: The traditional non-intrusive load monitoring (NILM) algorithms are mostly based on classification models, which have several deficiencies. Firstly, a large amount of labeled data is required to train the classification model. Secondly, these algorithms cannot identify unknown devices that frequently encountered in practical application. Finally, these models have poor performance in versatility, which means they only adapt to the trained data. These shortcomings greatly influence the practicality of these NILM algorithms. To tackle these problems, this paper has proposed a non-intrusive adaptive load identification model based on the Siamese network, which uses both the V-I trajectory and active power as the load signatures. The Siamese network is utilized to calculate the similarity of the V-I trajectory, and the load identification is realized by matching the signature with the feature library. Through adding new features to the feature library dynamically, the identification of unknown load can be realized. In addition, the Siamese network is a typical network for few-shot learning, thus the proposed model can be trained with a small number of samples to achieve ideal recognition effect. At last, the validity and versatility of the model are verified in PLAID dataset and COOLL dataset.\",\n \"Title: MesoGRU: Deep Learning Framework for Mesoscale Eddy Trajectory Prediction\\nYear: 2022\\n\\nAbstract: This work presents a novel framework, named MesoGRU, to accurately predict trajectories of mesoscale eddies (MEs), which is beneficial to study the natural ocean phenomena and perform statistical analysis of oceanic data. MesoGRU first extracts ME trajectory data and establishes two datasets according to the information of location and date in the South China Sea (SCS). Then it effectively processes SCS trajectory data and integrates SLA data and AVISO data into our combined ME dataset (CDME). Furthermore, a designated neural network with a new loss function [(weighted mean square estimation (WMSE)] is designed to learn the characteristics of ME trajectories. After thoroughly analyzing correlations of every two features, the MesoGRU network iteratively extracts key ME features and renormalizes the future time sequence of eddy trajectories. Our verification results demonstrate that MesoGRU has conducted a significant prediction improvement. The mean daily center error of ME trajectory prediction with our scheme is about 8 km and its center error for seven-day forecasting is approximately 18.2 km. Moreover, MesoGRU achieves a higher matching ratio of ME trajectory forecasting compared to other deep learning methods with a single dataset, indicating MesoGRU can predict trajectories as a state-of-the-art method.\",\n \"Title: Intelligent Intrusion Detection Based on Federated Learning for Edge-Assisted Internet of Things\\nYear: 2021\\n\\nAbstract: As an innovative strategy, edge computing has been considered a viable option to address the limitations of cloud computing in supporting the Internet-of-Things applications. However, due to the instability of the network and the increase of the attack surfaces, the security in edge-assisted IoT needs to be better guaranteed. In this paper, we propose an intelligent intrusion detection mechanism, FedACNN, which completes the intrusion detection task by assisting the deep learning model CNN through the federated learning mechanism. In order to alleviate the communication delay limit of federal learning, we innovatively integrate the attention mechanism, and the FedACNN can achieve ideal accuracy with a 50% reduction of communication rounds.\",\n \"Title: An Eco-Driving Strategy for Partially Connected Automated Vehicles at a Signalized Intersection\\nYear: 2022\\n\\nAbstract: We consider a signalized intersection under a partially connected automated vehicle (CAV) environment. There is a control center for the control zone that needs to predict the trajectories of human driving vehicles (HDVs) and control the trajectories of CAVs. By adopting model predictive control, we propose a real-time eco-driving strategy for the control center. In the proposed strategy, the Gipps' car-following model is selected to update the acceleration of HDV and an optimal control problem (OCP) is proposed to optimize the trajectory of each CAV based on real-time travel information. The control objective is to minimize the total fuel consumption of each CAV during the current control period. Pontryagin's minimum principle is employed to derive necessary optimality conditions under different scenarios. With the necessary optimality conditions, a numerical method is developed to solve the proposed OCP. Finally, numerical examples are provided to illustrate the performance of the proposed eco-driving strategy.\",\n \"Title: AF Relaying Secrecy Performance Prediction for 6G Mobile Communication Networks in Industry 5.0\\nYear: 2022\\n\\nAbstract: Industry 5.0 has developed in full swing, and accelerated the process of the sixth-generation (6G) mobile communication. Physical layer security is important for complex 6G mobile communication networks. To process active complex events in 6G mobile cooperative networks, predicting secrecy performance in time is essential for the mobile communication quality evaluation. Using amplify-and-forward (...\",\n \"Title: Comparison of Pond Depth and Ice Thickness Retrieval Algorithms for Summer Arctic Sea Ice\\nYear: 2022\\n\\nAbstract: In order to satisfy the demand of key sea ice parameters, including melt pond depth H-p and underlying ice thickness H-i, in studies of Arctic sea ice change in summer, four algorithms of retrieving H-p and H-i were compared and validated by using optical data of melt ponds from field observations. The Malinka18 algorithm stood out as the most accurate algorithm for the retrieval of H-p. For the retrieval of H-i, Malinka18 and Zhang21 algorithms could also provide reasonable results and both can be applied under clear and overcast sky conditions, while retrievals under clear sky conditions are more accurate. The retrieval results of H-i for Lu18 agreed better with field measurements for thin ice (H-i < 1 m) than that for thick ice, but those results of H-p were not satisfactory. The Konig20 algorithm was only suitable for clear sky conditions, and underestimated H-p, while showing a good agreement with H-p < 0.15 m. For Arctic applications, Malinka18 and Zhang21 algorithms provided a basis and reference for the satellite optical data such as WoeldView2 to retrieve H-p and H-i. Malimka18 also showed the ability to retrieve H-i, except for the Lu18 algorithm if pond color captured by helicopters and unmanned aerial vehicles were available. This study identifies the optimal algorithm for retrieval of H-p and H-i under different conditions, which have the potential to provide necessary data for numerical simulations of Arctic sea ice changes in summer.\",\n \"Title: An end-to-end single image dehazing network based on U-net\\nYear: 2022\\n\\nAbstract: Single image haze removal is always significant for computer advanced vision tasks, while it is also a challenging problem. In this paper, inspired of the recent methods, we proposed an end-to-end network with encoding–decoding structure and jumping layers for single image dehazing. The network combined the advantages of VGG16 and the U-net and adopted different jumping layers to retain most of the image feature information. In order to clarify the image features like contrast and color distribution, the scale-invariant loss function and the proposed histogram loss function were used. We compared the algorithm with the several state-of-the-art algorithms qualitatively and quantitatively. Experimental results demonstrated that the proposed algorithm has achieved favorable dehazing results on both indoor and outdoor synthetic hazy testing set and real-world set. In particular, it obtained the better dehazing results for the slight hazy conditions than other density of haze.\",\n \"Title: SALSTM: An improved LSTM algorithm for predicting the competitiveness of export products\\nYear: 2022\\n\\nAbstract: As international trade has been developing at an unprecedented rate, export product competitiveness is significant in a country's trade system. At present, neural network algorithms are extensively used in economic forecasting. Scholars have verified the effectiveness of neural networks, especially long short term memory (LSTM) model, compared with other nonlinear prediction methods. However, there are still research blanks in forecasting economic indicators related to export product competitiveness, and there is little research on the improved LSTM model combined with other algorithms. To address this limitation, this article established a quantitative index system for export product competitiveness composed of four highly recognized indicators such as revealed comparative advantage index, net export revealed comparative advantage index, international market share index, and economic value added. After collecting the relevant economic data, the single LSTM model was used to predict the future trend of China's machinery and equipment export product competitiveness. Based on the shortcomings exposed in applying single LSTM prediction, the article innovatively designs a combined forecast model of LSTM and seasonal autoregressive integrated moving average, and whose effectiveness and superiority are proved by the mean square error value. Finally, the article points out that this model plays an important role in national trade policy making. It is optimistic about the development of deep learning in international trade product competitiveness indicators prediction.\",\n \"Title: Referral strategies and capacity decisions in a tiered hospital system with gatekeeping designs — Exemplified with Chinese healthcare system\\nYear: 2022\\n\\nAbstract: We developed a model to formulate the referral process in a tiered hospital system involving a general hospital (GH) and community healthcare centers (CHCs), where green channels are built on priority. We propose two types of referral strategies to address delay-sensitive patients based on: (1) patients’ choice (PC) and (2) independent decision-making by the hospital (DMH). Through price subsidy and priority mechanism, both PC and DMH can effectively regulate patient choice behavior and guide all patients to choose a CHC for the first diagnosis. This could help the Chinese government implement a gatekeeping system even if free referral of patients is allowed. We determine the optimal capability decisions of the GH (for profit maximization) and each CHC (for maximization of patient utility), under two strategies. The main results are as follows: under PC, the referral process is controlled by the GH, but the government’s coordination tools (budget and tax rate) would not influence the GH’s decision on its optimal arrival rate with the green channel. In contrast, DMH offers the government more power to control the referral process using budget and tax rate. Numerical analysis provides managerial insights for the government to better use tax-subsidy policies and make an optimal choice between PC and DMH.\",\n \"Title: A Novel Transformer-Based Model for Dialog State Tracking\\nYear: 2022\\n\\nAbstract: Dialog state tracking (DST) is a core component in the task-oriented dialog systems. Many previous approaches regard DST as a classification task for a set of predefined slot-value pairs, but these approaches can not handle the situation of dynamic ontology. Other methods consider slot as span-based, while these methods are insufficient when the target slot-value cannot be found as a word segment in the dialog context. To mitigate these problems, we propose a Transformer-based model for DST. The proposed method can achieve the DST task by extracting the slot-value from the dialog context or classifying for the slot with limited values. Experimental evidence shows that our proposed model can achieve competitive performance on the WOZ 2.0 dataset while being 20\\n \\n \\n \\n $$\\\\times $$\\n \\n faster than the state-of-the-art model. To demonstrate the effectiveness of our proposed model on multi-domain, we experiment with the recently released MultiWOZ-2.0 dataset. The experiment shows that our model can achieve promising result.\",\n \"Title: Accurate and Efficient Performance Prediction for Mobile IoV Networks Using GWO-GR Neural Network\\nYear: 2022\\n\\nAbstract: The explosive growth of Internet of Vehicle (IoV) applications has made information security a significant issue. Mobile IoV users are dynamic and the communication environment is very complex, which makes it very difficult to guarantee real-time secrecy communication performance. Thus, a reliable and effective evaluation and prediction of secrecy performance is critical. In this article, we have derived novel expressions for secrecy performance. A grey wolf optimization generalized regression (GWO-GR) algorithm is proposed to predict the secrecy performance and carry out the secrecy performance assessment. A generalized regression (GR) neural network is designed. Out of the input and output layers, the proposed GR network has a pattern layer and a summation layer, which can obtain a global convergence of network results. To further optimize the GR network, the grey wolf optimization algorithm is used to obtain the best spread factor for it, which can accelerate its rapid convergence. Through the simulated numerical results, we can obtain: 1) the proposed GWO-GR prediction algorithm is shown to provide better performance prediction results than other machine-learning-based methods; 2) in particular, the prediction accuracy is improved by 17.7%; and 3) the execution time has an 88.9% reduction.\",\n \"Title: Trampoline Over the Air: Breaking in IoT Devices Through MQTT Brokers\\nYear: 2022\\n\\nAbstract: MQTT is widely adopted by IoT devices because it allows for the most efficient data transfer over a variety of communication lines. The security of MQTT has received increasing attention in recent years, and several studies have demonstrated the configurations of many MQTT brokers are insecure. Adversaries are allowed to exploit vulnerable brokers and publish malicious messages to subscribers. However, little has been done to understanding the security issues on the device side when devices handle unauthorized MQTT messages. To fill this research gap, we propose a fuzzing framework named ShadowFuzzer to find client-side vulnerabilities when processing incoming MQTT messages. To avoiding ethical issues, ShadowFuzzer redirects traffic destined for the actual broker to a shadow broker under the control to monitor vulnerabilities. We select 15 IoT devices communicating with vulnerable brokers and leverage ShadowFuzzer to find vulnerabilities when they parse MQTT messages. For these devices, ShadowFuzzer reports 34 zero-day vulnerabilities in 11 devices. We evaluated the exploitability of these vulnerabilities and received a total of 44,000 USD bug bounty rewards. And 16 CVE/CNVD/CN-NVD numbers have been assigned to us.\",\n \"Title: A Multilevel Remote Relational Modeling Network for Accurate Segmentation of Fundus Blood Vessels\\nYear: 2022\\n\\nAbstract: Accurate segmentation of retinal blood vessels is an important prerequisite for diagnosing many fundus diseases. Many methods based on artificially designed convolutional neural networks (CNNs) have been successively proposed and achieved good results. However, the image quality collected by fundus camera is poor, and the vessels topology in the image is complex, the pure convolution feature extraction in these CNN methods is limited. A novel multilevel remote relational modeling network (MRRM-Net) is proposed, which can balance global/local long-range contextual relations through building multidimensional and multilevel attention. Based on the symmetric structure, we first design the three-dimensional guided attention module (TGAM) in the encoder to establish long-range dependency descriptions with semantically rich spatial structure through similarity and then design a cross-level sensitive attention module (CSAM) at the skip connection position to adaptively and dynamically correct low-level error information while strengthening the long-range spatial structure features established by the attention guidance module. These two modules can gradually establish and fuse the long-range semantic context. Furthermore, we propose a novel feature fusion method (FFM) to pass high-level semantics into the decoder. The experimental results show that our proposed method has better superiority, especially for capillaries with complex background and variable structure, and has more robust data adaptability than other state-of-the-art network structures in a small capacity. On multiple public datasets, it shows better stability. MRRM-Net can provide a theoretical basis for real-time detection technology of retinopathy.\",\n \"Title: A Review of Virtual Reality in Language Learning from 2011 to 2020\\nYear: 2022\\n\\nAbstract: The utilization of virtual reality (VR) in the field of language learning is a hot issue for both educational practitioners and researchers. This research summarized the empirical studies on applying VR in language learning from 2011 to 2020. The authors analyzed a total of 67 empirical studies in twelve peer-reviewed journals. On the basis of the coding framework, we used content analysis for further data analysis. The current study revealed the general research status, major research themes of the empirical studies and the guiding theories for the instructional design with VR. The advantages and challenges of integrating VR to language learning were summarized in the end.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":170,"string":"170"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13355,"string":"13,355"}}},{"rowIdx":13356,"cells":{"question_id":{"kind":"string","value":"Hung Son Nguyen"},"question":{"kind":"string","value":"Generate an abstract for the title \"An Approach to Mining Data with Continuous Decision Values\" using the following items: 1. Novel approach \n2. Ill-defined decision tables \n3. Two-layered learning algorithm \n4. Preference relation \n5. Applications: ranking order, decision value prediction, optimization."},"answer":{"kind":"string","value":"We propose a novel approach to discover useful patterns from ill-defined decision tables with a real value decision and nominal conditional attributes. The proposed solution is based on a two-layered learning algorithm. In the first layer the preference relation between objects is approximated from the data. In the second layer the approximated preference relation is used to create three applications: (1) to learn a ranking order on a collection of combinations, (2) to predict the real decision value, (3) to optimize the process of searching for the combination with maximal decision."},"correct_answer":{"kind":"string","value":"We propose a novel approach to discover useful patterns from ill-defined decision tables with a real value decision and nominal conditional attributes. The proposed solution is based on a two-layered learning algorithm. In the first layer the preference relation between objects is approximated from the data. In the second layer the approximated preference relation is used to create three applications: (1) to learn a ranking order on a collection of combinations, (2) to predict the real decision value, (3) to optimize the process of searching for the combination with maximal decision."},"documents":{"kind":"list like","value":["Title: Hierarchical Rough Classifiers\nYear: 2007\n\nAbstract: The major applications of rough set theory in data mining are related to the modeling of concepts using rough classifiers,\n i.e., the algorithms classifying unseen objects into lower or upper approximations of concepts. This paper investigates a\n class of compound classifiers called multi-level (or hierarchical) rough classifiers (MLRC). We present the most recent issues\n on the construction of such classifiers from data using concept ontology as an additional domain knowledge. The idea is based\n on the bottom-up manner to gradually synthesize the multi-layer rough classifier for the complex target concept from the simpler\n classifiers.We illustrate the proposed method by experiments on real-life data.","Title: Learning Sunspot Classification\nYear: 2006\n\nAbstract: Sunspots are the subject of interest to many astronomers and solar physicists. Sunspot observation, analysis and classification form an important part of furthering the knowledge about the Sun. Sunspot classification is a manual and very labor intensive process that could be automated if successfully learned by a machine. This paper presents machine learning approaches to the problem of sunspot classification. The classification scheme attempted was the seven-class Modified Zurich scheme [18]. The data was obtained by processing NASA SOHO/MDI satellite images to extract individual sunspots and their attributes. A series of experiments were performed on the training dataset with an aim of learning sunspot classification and improving prediction accuracy. The experiments involved using decision trees, rough sets, hierarchical clustering and layered learning methods. Sunspots were characterized by their visual properties like size, shape, positions, and were manually classified by comparing extracted sunspots with corresponding active region maps (ARMaps) from the Mees Observatory at the Institute for Astronomy, University of Hawaii.","Title: Rough sets and association rule generation\nYear: 1999\n\nAbstract: ASSOCIATION RULE (see [1]) extraction methods have been developed as the main methods for mining of real life data, in particular in Basket Data Analysis. In this paper we present a novel approach to generation of association rules, based on Rough Set and Boolean reasoning methods. Some results presented in this paper has been mentioned in [13, 17]. We will explain them precisely (with full proofs of theorems) in this paper. We show the relationship between the problems of association rule extraction for transaction data and relative reducts (or α-reducts generation) for a decision table. Moreover, the present approach can be used to extract association rules in general form. The experimental results show that the presented methods are quite efficient. Large number of association rules with given support and confidence can be extracted in a short time.","Title: A Soft Decision Tree\nYear: 2002\n\nAbstract: Searching for binary partition of attribute domains is an important task in Data Mining, particularly in decision tree methods. The most important advantage of decision tree methods are based on compactness and clearness of presented knowledge and high accuracy of classification. In case of large data tables, the existing decision tree induction methods often show to be inecient in both computation and description aspects. The disadvantage of standard decision tree methods is also their instability, i.e., small deviation of data perhaps cause a total change of decision tree. We present the novel \"soft discretization\" methods using \"soft cuts\" instead of traditional \"crisp\" (or sharp) cuts. This new concept allows to generate more compact and stable decision trees with high classification accuracy. We also present an ecient","Title: Lexicon-based Document Representation\nYear: 2013\n\nAbstract: It is a big challenge for an information retrieval system IRS to interpret the queries made by users, particularly because the common form of query consists of very few terms. Tolerance rough sets models TRSM, as an extension of rough sets theory, have demonstrated their ability to enrich document representation in terms of semantic relatedness. However, system efficiency is at stake because the weight vector created by TRSM TRSM-representation is much less sparse. We mapped the terms occurring in TRSM-representation to terms in the lexicon, hence the final representation of a document was a weight vector consisting only of terms that occurred in the lexicon LEX-representation. The LEX-representation can be viewed as a compact form of TRSM-representation in a lower dimensional space and eliminates all informal terms previously occurring in TRSM-vector. With these facts, we may expect a more efficient system. We employed recall and precision commonly used in information retrieval to evaluate the effectiveness of LEX-representation. Based on our examination, we found that the effectiveness of LEX-representation is comparable with TRSM-representation while the efficiency of LEX-representation should be better than the existing TRSM-representation. We concluded that lexicon-based document representation was another alternative potentially used to represent a document while considering semantics. We are tempted to implement the LEX-representation together with linguistic computation, such as tagging and feature selection, in order to retrieve more relevant terms with high weight. With regard to the TRSM method, enhancing the quality of tolerance class is crucial based on the fact that the TRSM method is fully reliant on the tolerance classes. We plan to combine other resources such as Wikipedia Indonesia to generate a better tolerance class.","Title: Pattern extraction from data\nYear: 1998\n\nAbstract: Searching for patterns is one of the main goals in data mining. Patterns have important applications in many KDD domains like rule extraction or classification. In this paper we present some methods of rule extraction by generalizing the existing approaches for the pattern problem. These methods, called partition of attribute values or grouping of attribute values, can be applied to decision tables with symbolic value attributes. If data tables contain symbolic and numeric attributes, some of the proposed methods can be used jointly with discretization methods. Moreover, these methods are applicable for incomplete data. The optimization problems for grouping of attribute values are either NP-complete or NP-hard. Hence we propose some heuristics returning approximate solutions for such problems.","Title: Rough Set Methods in Approximation of Hierarchical Concepts\nYear: 2004\n\nAbstract: Many learning methods ignore domain knowledge in synthesis of concept approximation. We propose to use hierarchical schemes for learning approximations of complex concepts from experimental data using inference diagrams based on domain knowledge. Our solution is based on the rough set and rough mereological approaches. The effectiveness of the proposed approach is performed and evaluated on artificial data sets generated by a traffic road simulator.","Title: RSCTC'2010 discovery challenge: mining DNA microarray data for medical diagnosis and treatment\nYear: 2010\n\nAbstract: RSCTC'2010 Discovery Challenge was a special event of Rough Sets and Current Trends in Computing conference. The challenge was organized in the form of an interactive on-line competition, at TUNEDIT.org platform, in days between Dec 1, 2009 and Feb 28, 2010. The task was related to feature selection in analysis of DNA microarray data and classification of samples for the purpose of medical diagnosis or treatment. Prizes were awarded to the best solutions. This paper describes organization of the competition and the winning solutions.","Title: Fast split selection method and its application in decision tree construction from large databases\nYear: 2005\n\nAbstract: We present an efficient method for decision tree construction from large data sets, which are assumed to be stored in database servers, and be accessible by SQL queries. The proposed method minimizes the number of simple queries necessary to search for the best splits (cut points) by employing \"divide and conquer\" search strategy. To make it possible, we develop some novel evaluation measures which are defined on intervals of attribute domains. Proposed measures are necessary to estimate the quality of the best cut in a given interval. We propose some applications of the presented approach in discretization and construction of \"soft decision tree\", which is a novel classifier model.","Title: An Algorithm for Tolerance Value Generator in Tolerance Rough Sets Model.\nYear: 2012\n\nAbstract: The Tolerance Rough Sets Model (TRSM) is a tool to model document in text mining. Generation of a document representation based on TRSM basically depends on tolerance classes of terms which are created by setting up a tolerance value. Despite the fact that tolerance value is critical in TRSM, the manual process of setting this value is an exhaustive task. We conducted a study on our own corpus and were supported by two human experts when constructing the training data. We came up with a novel algorithm to generate tolerance value automatically from a set of training data. The heart of our algorithm is measuring the distance between document representation calculated using TFIDF weighting scheme and document representation yielded by TRSM both in reduced dimensional space generated by Singular Value Decomposition (SVD). In spite of the result, we recognize that further study is significant, i.e. to set up some properties (the size of training data and rank of SVD) as well as evaluating the algorithm in real data and scenario.","Title: Knowledge discovery by relation approximation: a rough set approach\nYear: 2006\n\nAbstract: In recent years, rough set theory [1] has attracted attention of many researchers and practitioners all over the world, who have contributed essentially to its development and applications. With many practical and interesting applications rough set approach seems to be of fundamental importance to AI and cognitive sciences, especially in the areas of machine learning, knowledge acquisition, decision analysis, knowledge discovery from databases, expert systems, inductive reasoning and pattern recognition [2]","Title: A method of Web search result clustering based on rough sets\nYear: 2005\n\nAbstract: Due to the enormous size of the Web and low precision of user queries, finding the right information from the Web can be difficult if not impossible. One approach that tries to solve this problem is using clustering techniques for grouping similar document together in order to facilitate presentation of results in more compact form and enable thematic browsing of the results set. The main problem of many Web search result (snippet) clustering algorithm is based on the poor vector representation of snippets. In this paper, we present a method of snippet representation enrichment using tolerance rough set model. We applied the proposed method to construct a rough set based search result clustering algorithm and compared it with other recent methods.","Title: Investigating the effectiveness of thesaurus generated using tolerance rough set model\nYear: 2011\n\nAbstract: We considered the tolerance matrix generated using tolerance rough set model as a kind of an associative thesaurus. The effectiveness of the thesaurus was measured using performance measures commonly used in information retrieval, recall and precision, where they were used for the terms rather than documents. A corpus consists of keywords defined as highly related with particular topic by human experts become the ground truth of this study. Analysis was conducted based on comparison values of all available sets created. Above all findings, this paper was thought as the fundamental basis that generating an automatic thesaurus using rough sets theory is a promising way. We also mentioned some directions for future study.","Title: Approximated measures in construction of decision trees from large databases\nYear: 2003\n\nAbstract: We present an efficient method for decision tree construction from large data set, which is assumed to be stored in some database server, and to be accessible by SQL queries. We develop a decision tree construction method, which minimizes the total time of data transmission between client and server. Our method, based on divide and conqurer search strategy, minimizes the number of simple queries necessary to search for the best cuts. To make it possible, we develop some, approximate measures, defined on intervals of attribute values, to evaluate the chance that the best cut belongs to the given interval. We propose some applications of the presented approach in discretization and construction of soft decision tree, which is a novel classifier model.","Title: Metric Based Attribute Reduction in Incomplete Decision Tables.\nYear: 2013\n\nAbstract: Metric technique has recently been applied to solve such data mining problems as classification, clustering, feature selection, decision tree construction. In this paper, we apply metric technique to solve a attribute reduction problem of incomplete decision tables in rough set theory. We generalize Liang entropy in incomplete information systems and investigate its properties. Based on the generalized Liang entropy, we establish a metric between coverings and study its properties for attribute reduction. Consequently, we propose a metric based attribute reduction method in incomplete decision tables and perform experiments on UCI data sets. The experimental results show that metric technique is an effective method for attribute reduction in incomplete decision tables.","Title: Scalable Classification Method Based on Rough Sets\nYear: 2002\n\nAbstract: The existing rough set based methods are not applicable for large data set because of the high time and space complexity and the lack of scalability. We present a classification method, which is equivalent to rough set based classification methods, but is scalable and applicable for large data sets. The proposed method is based on lazy learning idea [2] and Apriori algorithm for sequent item-set approaches [1]. In this method the set of decision rules matching the new object is generated directly from training set. Accept classification task, this method can be used for adaptive rule generation system where data is growing up in time.","Title: Approximate Reducts and Association Rules - Correspondence and Complexity Results\nYear: 1999\n\nAbstract: . We consider approximate versions of fundamental notions oftheories of rough sets and association rules. We analyze the complexityof searching for ff-reducts, understood as subsets discerning "ff-almost"objects from different decision classes, in decision tables. We present howoptimal approximate association rules can be derived from data by usingheuristics for searching for minimal ff-reducts. NP-hardness of the problemof finding optimal approximate association rules is shown as...","Title: Rough Set Approach to KDD (Extended Abstract)\nYear: 2008\n\nAbstract: This tutorial is a survey on rough set theory and some of its applications in Knowledge Discovery from Databases (KDD). It\n will also cover the practice guide to analysis of different real life problems using rough set methods as well as the presentation\n of Rough Set Exploration System (RSES) what can be treated as a preliminary material for the main conference and associated\n workshops.\n \n Rough Set theory was introduced by Zdzisław Pawlak in the early 80’s and has currently reached a level of high visibility\n and maturity [3,2,4,5,6] Originally, rough sets, whose main philosophy is based simply on indiscernibility and discernibility\n of objects, were presented as an approach to concept approximation under uncertainty. This brilliantly simple idea has been\n successively expanded in the last twenty years. Many effective methods for data analysis have been developed on the basis\n of rough set theory.","Title: Rough set approach to sunspot classification problem\nYear: 2005\n\nAbstract: This paper presents an application of hierarchical learning method based rough set theory to the problem of sunspot classification from satellite images. The Modified Zurich classification scheme [3] is defined by a set of rules containing many complicated and unprecise concepts, which cannot be determined directly from solar images. The idea is to represent the domain knowledge by an ontology of concepts – a treelike structure that describes the relationship between the target concepts, intermediate concepts and attributes. We show that such ontology can be constructed by a decision tree algorithm and demonstrate the proposed method on the data set containing sunspot extracted from satellite images of solar disk.","Title: Approximate boolean reasoning approach to rough sets and data mining\nYear: 2005\n\nAbstract: Many problems in rough set theory have been successfully solved by boolean reasoning (BR) approach. The disadvantage of this elegant methodology is based on its high space and time complexity. In this paper we present a modified BR approach that can overcome those difficulties. This methodology is called the approximate boolean reasoning (ABR) approach. We summarize some most recent applications of ABR approach in development of new efficient algorithms in rough sets and data mining.","Title: Boolean Reasoning Scheme with Some Applications in Data Mining\nYear: 1999\n\nAbstract: We present a general encoding scheme for a wide class of problems (including among others such problems like data reduction, feature selection, feature extraction, decision rules generation, pattern extraction from data or conflict resolution in multi-agent systems) and we show how to combine it with a propositional (Boolean) reasoning to develop efficient heuristics searching for (approximate) solutions of these problems. We illustrate our approach by examples, we show some experimental results and compare them with those reported in literature. We also show that association rule generation is strongly related with reduct approximation.","Title: Decomposition of Task Specification Problems\nYear: 1999\n\nAbstract: . We consider a synthesis of complex objects by multi-agentsystem based on rough mereological approach. Any agent can producecomplex objects from parts obtained from his sub-agents using somecomposition rules. Agents are equipped with decision tables describing(partial) specifications of their synthesis tasks. We investigate some problemsof searching for optimal task specifications for sub-agents havingtask specification for a super-agent. We propose a decomposition schemeconsistent with ...","Title: Bisimulation-Based Concept Learning in Description Logics\nYear: 2013\n\nAbstract: Concept learning in description logics (DLs) is similar to binary classification in traditional machine learning. The difference is that in DLs objects are described not only by attributes but also by binary relationships between objects. In this paper, we develop the first bisimulation-based method of concept learning in DLs for the following setting: given a knowledge base KB in a DL, a set of objects standing for positive examples and a set of objects standing for negative examples, learn a concept C in that DL such that the positive examples are instances of C w.r.t. KB, while the negative examples are not instances of C w.r.t. KB. We also prove soundness of our method and investigate its C-learnability.","Title: Neural Networks Design: Rough Set Approach to Continuous Data\nYear: 1997\n\nAbstract: . The construction of neural network based on decision rulesgenerated by rough set methods is given. Analogies between neural networksemantics and rough set approach to continuous data are pointedout. General framework states the initial point for such applications like,e.g., tuning decision rules by neural network learning process.1 IntroductionThe task of dealing with real-valued datasets seems to be one of key issues indecision support systems. Many approaches have been...","Title: An Approach to Pattern Recognition Based on Hierarchical Granular Computing\nYear: 2013\n\nAbstract: This paper summarizes the some of the recent developments in the area of application of rough sets and granular computing in hierarchical learning. We present the general framework of rough set based hierarchical learning. In particular, we investigate several strategies of choosing the appropriate learning algorithms for first level concepts as well as the learning methods for the intermediate concepts. We also propose some techniques for embedding the domain knowledge into the granular, layered learning process in order to improve the quality of hierarchical classifiers. This idea, which has been envisioned and developed by professor Andrzej Skowron over the last 10 years, shows to be very efficient in many practical applications. Throughout the article, we illustrate the proposed methodology with three case studies in the area of pattern recognition. The studies demonstrate the viability of this approach for such problems as: sunspot classification, hand-written digit recognition, and car identification.","Title: A bisimulation-based method of concept learning for knowledge bases in description logics\nYear: 2012\n\nAbstract: We develop the first bisimulation-based method of concept learning, called BBCL, for knowledge bases in description logics (DLs). Our method is formulated for a large class of useful DLs, with well-known DLs like ALC, SHIQ, SHOIQ, SROIQ. As bisimulation is the notion for characterizing indis-cernibility of objects in DLs, our method is natural and very promising.","Title: On Learning of Sunspot Classification\nYear: 2004\n\nAbstract: This paper describes automatic sunspot recognition and classification from satellite images. Some experimental results on learning sunspot classification using data mining techniques are presented. The classification scheme used was the seven-class Modified Zurich scheme. Daily images of the solar disk were taken from the NASA SOHO satellite's MDI instrument and sunspots extracted using image processing techniques. Two data mining tools, WEKA and RSES, were used for learning sunspot classification. In the training dataset sunspots were manually classified by comparing extracted sunspots with corresponding active region maps.","Title: Boolean Reasoning for Feature Extraction Problems\nYear: 1997\n\nAbstract: . We recall several applications of Boolean reasoning for featureextraction and we propose an approach based on Boolean reasoningfor new feature extraction from data tables with symbolic (nominal, qualitative)attributes. New features are of the form a 2 V , where V ` Vaand Va is the set of values of attribute a. We emphasize that Booleanreasoning is also a good framework for complexity analysis of the approximatesolutions of the discussed problems.1 Introduction"Feature Extraction"...","Title: Semantic explorative evaluation of document clustering algorithms\nYear: 2013\n\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. We propose a novel approach to construction of evaluation measure, which is based on the Minimal Description Length (MDL) principle. In fact this proposed measure, called SEE (Semantic Evaluation by Exploration), is an improvement of the existing evaluation methods such as Rand Index or Normalized Mutual Information. It fixes some of weaknesses of the original methods. We illustrate the proposed evaluation method on the freely accessible biomedical research articles from Pubmed Central (PMC). Many articles from Pubmed Central are annotated by the experts using Medical Subject Headings (MeSH) thesaurus. This paper is a part of the research on designing and developing a dialog-based semantic search engine for SONCA system which is a part of the SYNAT project. We compare different semantic techniques for search result clustering using the proposed measure.","Title: On Scalability of Rough Set Methods\nYear: 2010\n\nAbstract: This paper presents some recent results of the research on the scalability of rough set based classification methods. The proposed solution is based on the close relationship between reduct calculation problem in rough set theory and association rule generation problem. This is a continuation of our previous results (see, e.g. [10] [11]). In this paper, the set of decision rules satisfying the test object is generated directly from the training data set. To make it scalable, we adopted the idea of the FP-growth algorithm for frequent item-sets [7], [6]. The experimental results on some benchmark data sets are showing the ability of the proposed solution to process a growing data sets.","Title: Enhancing search result clustering with semantic indexing\nYear: 2012\n\nAbstract: Semantic search results clustering is one of the most wanted functionalities of many information retrieval systems including general web search engines as well as domain specific article portals or digital libraries. It may advice the users to describe the need for information in a more precise way. In this paper, we discuss a framework of document description extension which utilizes domain knowledge and semantic similarity. Our idea is based on application of Tolerance Rough Set Model, semantic information extracted from source text and domain ontology to approximate concepts associated with documents and to enrich the vector representation. Some document representation models including document meta-data, citations and semantic information build using MeSH ontology. We compare those models in a search result clustering problem over the freely accessed biomedical research articles from Pubmed Cetral (PMC) portal. The experimental results are showing the advantages of the proposed models.","Title: Layered Learning for Concept Synthesis\nYear: 2004\n\nAbstract: We present a hierarchical scheme for synthesis of concept approximations based on given data and domain knowledge. We also propose a solution, founded on rough set theory, to the problem of constructing the approximation of higher level concepts by composing the approximation of lower level concepts. We examine the effectiveness of the layered learning approach by comparing it with the standard learning approach. Experiments are carried out on artificial data sets generated by a road traffic simulator.","Title: On Efficient Construction of Decision Trees from Large Databases\nYear: 2000\n\nAbstract: The main taskin decision tree construction algorithms is to find the “best partition” of the set of objects. In this paper,\n we investigate the problem of optimal binary partition of continuous attribute for large data sets stored in relational databases. The critical for time complexity of algorithms solving this problem is the number of simple SQL queries necessary to construct\n such partitions. The straightforward approach to optimal partition selection needs at least O(N) queries, where N is the number of pre-assumed partitions of the searching space. We show some properties of optimization measures related\n to discernibility between objects, that allow to construct the partition very close to optimal using only O(logN) simple queries.","Title: Discretization Problem for Rough Sets Methods\nYear: 1998\n\nAbstract: We study the relationship between reduct problem in Rough Sets theory and the problem of real value attribute discretization. We consider the problem of searching for a minimal set of cuts on attribute domains that preserves discernibility of objects with respect to any chosen attributes subset of cardinality s (where s is a parameter given by a user). Such a discretization procedure assures that one can keep all reducts consisting of at least s attributes. We show that this optimization problem is NP-hard and it is interesting to find efficient heuristics for solving this problem.","Title: (No) Sql Platform For Scalable Semantic Processing Of Fast Growing Document Repositories\nYear: 2012\n\nAbstract: Large volumes of scientific data require specific storage and indexing solutions to maximize the effectiveness of searches. Semantic indexing algorithms use domain knowledge to group and rank sets of objects of interest, such as publications, scientists, institutes, and scientific concepts. Their implementation is often based on massively parallel solutions employing NoSQL platforms, although different types of semantic processing operations should be scaled with respect to the growing volumes of scientific information using different database methodologies [1].","Title: On c-learnability in description logics\nYear: 2012\n\nAbstract: We prove that any concept in any description logic that extends $\\mathcal{ALC}$ with some features amongst I (inverse), Qk (quantified number restrictions with numbers bounded by a constant k), Self (local reflexivity of a role) can be learnt if the training information system is good enough. That is, there exists a learning algorithm such that, for every concept C of those logics, there exists a training information system consistent with C such that applying the learning algorithm to the system results in a concept equivalent to C.","Title: On elimination of redundant attributes in decision tables\nYear: 2012\n\nAbstract: Most decision support systems based on rough set theory are related to the minimal reduct calculation problem, which is NP-hard. This paper investigates the problem of searching for the set of useful attributes that occur in at least one reduct. By compliment, this problem is equivalent to searching for the set of redundant attributes, i.e. the attributes that do not occur in any reducts of the given decision table. We show that the considered problem is equivalent to a Sperner system for relational data base system and prove that it can be solved in polynomial time. On the base of these theoretical results, we also propose some algorithms for elimination of redundant attributes in decision tables.","Title: On the Decision Table with Maximal Number of Reducts\nYear: 2003\n\nAbstract: Searching for reducts is a basic problem for many rough set methods like rule induction, classification, etc., Many of them can not be realized in exact way because of existing possibly exponential number of (relative) reducts in decision tables. In this paper we investigate properties of the most malicious decision tables, i.e., tables with maximal number of reducts. We show that in such systems, the number of objects must be also exponential. The presented method is based on Boolean reasoning approach.","Title: Semantic Evaluation of Text Clustering.\nYear: 2014\n\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. We propose a novel approach to construction of evaluation measure, called SEE (Semantic Evaluation by Exploration), which is an improvement of the existing methods such as Rand Index or Normalized Mutual Information. We illustrate the proposed evaluation method on the freely accessible biomedical research articles from Pubmed Central (PMC). Many articles from Pubmed Central are annotated by the experts using Medical Subject Headings (MeSH) thesaurus. We compare different semantic techniques for search result clustering using the proposed measure.","Title: Scalable Methods in Rough Sets\nYear: 2010\n\nAbstract: In this paper we investigate the scalability features of rough set based methods in the context of their applicability in knowledge discovery from databases (KDD) and data mining. We summarize some previously known scalable methods and present one of the latest scalable rough set classifiers. The proposed solution is based on the relationship between rough sets and association discovering methods, which has been described in our previous papers [10] [11]. In this paper, the set of decision rules satisfying the test object is generated directly from the training data set. To make it scalable, we adopted the idea of the FP-growth algorithm for frequent item-sets [7], [6]. The proposed method can be applied in construction of incremental rule-based classification system for stream data.","Title: Semantic analytics of pubmed content\nYear: 2011\n\nAbstract: We present an architecture aimed at semantic search and synthesis of information acquired from the document repositories. The proposed framework is expected to provide domain knowledge interfaces enabling the internally implemented algorithms to identify relationships between documents, researchers, institutions, as well as concepts extracted from various types of knowledge bases. The framework should be scalable with respect to data volumes, diversity of analytic processes, and the speed of search. In this paper, we investigate these requirements for the case of medical publications gathered in PubMed.","Title: Text Classification Using Lattice Machine\nYear: 1999\n\nAbstract: A novel approach to supervised learning, called Lattice Machine, was proposed in [5]. In the Lattice Machine, it was assumed that data are structured as relations. In this paper we investigate\n the application of the Lattice Machine in the area of text classification, where textual data are unstructured. We represent\n a set of textual documents as a collection of Boolean feature vectors, where each vector corresponds to one document and each\n entry in a tuple indicates whether a particular term appears in the document. This is a common representation of textual documents.\n We show that using this representation, the Lattice Machine’s operations are simply set theoretic operations. In particular,\n the lattice sum operation is simply set intersection and the ordering relationship is simply set inclusion. Experiments show\n that the Lattice Machine, under this configuration, is quite competitive with state-of-the-art learning algorithms for text\n classification.","Title: Situation Identification by Unmanned Aerial Vehicle\nYear: 2000\n\nAbstract: An approach to a multi-facet task of situation identification by Unmanned Aerial Vehicle (UAV) is presented. The concept of multi-layered identification system based on soft computing approach to reasoning with incomplete, imprecise or vague information is discussed.","Title: Approximate Boolean Reasoning: Foundations and Applications in Data Mining\nYear: 2006\n\nAbstract: Since its introduction by George Boole during the mid-1800s, Boolean algebra has become an important part of the lingua franca of mathematics, science, engineering, and research in artificial intelligence, machine learning and data mining. The Boolean reasoning approach has manifestly become a powerful tool for designing effective and accurate solutions for many problems in decision-making and approximate reasoning optimization. In recent years, Boolean reasoning has become a recognized technique for developing many interesting concept approximation methods in rough set theory. The problem considered in this paper is the creation of a general framework for concept approximation. The need for such a general framework arises in machine learning and data mining. This paper presents a solution to this problem by introducing a general framework for concept approximation which combines rough set theory, Boolean reasoning methodology and data mining. This general framework for approximate reasoning is called Rough Sets and Approximate Boolean Reasoning (RSABR). The contribution of this paper is the presentation of the theoretical foundation of RSABR as well as its application in solving many data mining problems and knowledge discovery in databases (KDD) such as feature selection, feature extraction, data preprocessing, classification of decision rules and decision trees, association analysis.","Title: On Efficient Handling of Continuous Attributes in Large Data Bases\nYear: 2001\n\nAbstract: Some data mining techniques, like discretization of continuous attributes or decision tree induction, are based on searching for an optimal partition of data with respect to some optimization criteria. We investigate the problem of searching for optimal binary partition of continuous attribute domain in case of large data sets stored in relational data bases (RDB). The critical for time complexity of algorithms solving this problem is the number of I/O database operations necessary to construct such partitions. In our approach the basic operators are defined by queries on the number of objects characterized by means of real value intervals of continuous attributes. We assume the answer time for such queries does not depend on the interval length. The straightforward approach to the optimal partition selection (with respect to a given measure) requires O(N) basic queries, where N is the number of preassumed partition parts in the searching space. We show properties of the basic optimization measures making possible to reduce the size of searching space. Moreover, we prove that using only O(log N) simple queries, one can construct a partition very close to optimal.","Title: Searching for Features Defined by Hyperplanes\nYear: 1996\n\nAbstract: . We consider decision tables with real value conditional attributesand we present a method for extraction of features defined byhyperplanes in a multi-dimensional affine space. These new features areoften more relevant for object classification than the features definedby hyperplanes parallel to axes. The method generalizes an approachpresented in [18] in case of hyperplanes not necessarily parallel to theaxes. We propose genetic strategies searching for hyperplanes discerningbetween...","Title: IEEE ICDM 2010 Contest: TomTom Traffic Prediction for Intelligent GPS Navigation\nYear: 2010\n\nAbstract: In this foreword, we summarize the IEEE ICDM 2010 Contest: “TomTom Traffic Prediction for Intelligent GPS Navigation”. The challenge was held between Jun 22, 2010 and Sep 7, 2010 as an interactive on-line competition, using the TunedIT platform (http://tunedit.org). We present the scope of the ICDM contest series in general, the scope of this year’s contest, description of its tasks, statistics about participation, details about the TunedIT platform and the Traffic Simulation Framework. A detailed description of winning solutions is part of this proceeding series.","Title: Analysis of Image Sequences for the Unmanned Aerial Vehicle\nYear: 2001\n\nAbstract: A method for extracting relevant information from image sequence data is presented. The image sequences, being output of video system of the Unmanned Aerial Vehicle, are analysed with use of EM-clustering techniques and Rough Set based methods. The possibilities of construction of an automated system for recognition/identification of cars on the road, on the basis of colour-related data are discussed.","Title: A tolerance rough set approach to clustering web search results\nYear: 2004\n\nAbstract: Two most popular approaches to facilitate searching for information on the web are represented by web search engine and web\n directories. Although the performance of search engines is improving every day, searching on the web can be a tedious and\n time-consuming task due to the huge size and highly dynamic nature of the web. Moreover, the user’s “intention behind the\n search” is not clearly expressed which results in too general, short queries. Results returned by search engine can count\n from hundreds to hundreds of thousands of documents.\n \n \n One approach to manage the large number of results is clustering. Search results clustering can be defined as a process of automatical grouping search results into to thematic groups. However, in contrast to traditional document clustering, clustering of search results are done on-the-fly (per user query\n request) and locally on a limited set of results return from the search engine. Clustering of search results can help user\n navigate through large set of documents more efficiently. By providing concise, accurate description of clusters, it lets\n user localizes interesting document faster.\n \n \n \n In this paper, we proposed an approach to search results clustering based on Tolerance Rough Set following the work on document\n clustering [4,3]. Tolerance classes are used to approximate concepts existed in documents. The application of Tolerance Rough\n Set model in document clustering was proposed as a way to enrich document and cluster representation with the hope of increasing\n clustering performance.","Title: Granular Computing: A Rough Set Approach\nYear: 2001\n\nAbstract: We discuss information granule calculi as a basis of granular computing. They are defined by constructs like information granules, basic relations of inclusion and closeness between information granules as well as operations on them. The exact interpretation between granule languages of different information sources (agents) often does not exist. Hence (rough) inclusion and closeness of granules are considered instead of their equality. Examples of all the basic constructs of information granule calculi are presented. The construction of more complex information granules is described by expressions called terms. We discuss the synthesis problem of robust terms, i.e., descriptions of information granules, satisfying a given specification in a satisfactory degree. We also present a method for synthesis of information granules represented by robust terms (approximate schemes of reasoning) by means of decomposition of specifications for such granules. The discussed problems of granular computing are of special importance for many applications, in particular related to spatial reasoning as well as to knowledge discovery and data mining.","Title: Unsupervised Similarity Learning from Textual Data\nYear: 2012\n\nAbstract: This paper presents a research on the construction of a new unsupervised model for learning a semantic similarity measure from text corpora. Two main components of the model are a semantic interpreter of texts and a similarity function whose properties are derived from data. The first one associates particular documents with concepts defined in a knowledge base corresponding to the topics covered by the corpus. It shifts the representation of a meaning of the texts from words that can be ambiguous to concepts with predefined semantics. With this new representation, the similarity function is derived from data using a modification of the dynamic rule-based similarity model, which is adjusted to the unsupervised case. The adjustment is based on a novel notion of an information bireduct having its origin in the theory of rough sets. This extension of classical information reducts is used in order to find diverse sets of reference documents described by diverse sets of reference concepts that determine different aspects of the similarity. The paper explains a general idea of the approach and also gives some implementation guidelines. Additionally, results of some preliminary experiments are presented in order to demonstrate usefulness of the proposed model.","Title: Concept Learning for Description Logic-Based Information Systems\nYear: 2012\n\nAbstract: The work [1] by Nguyen and Szalas is a pioneering one that uses bisimulation for machine learning in the context of description logics. In this paper we generalize and extend their concept learning method [1] for description logic-based information systems. We take attributes as basic elements of the language. Each attribute may be discrete or numeric. A Boolean attribute is treated as a concept name. This approach is more general and much more suitable for practical information systems based on description logic than the one of [1]. As further extensions we allow also data roles and the concept constructors \"functionality\" and \"unquantified number restrictions\". We formulate and prove an important theorem on basic selectors. We also provide new examples to illustrate our approach.","Title: Sequential pattern mining from stream data\nYear: 2011\n\nAbstract: Sequential Pattern Mining, briefly SPM, is an interesting issue in Data Mining that can be applied for temporal or time series data. This paper is related to SPM algorithms that can work with stream data. We present three new stream SPM methods, called SS-BE2, SS-LC and SS-LC2, which are the extensions of SS-BE. The proposed methods, similarly to SS-BE, are dealing with fixed-sized batches using PrefixSpan algorithm, and the critical problem in each step is how to store the huge amount of candidate patterns, and how to select the frequent patterns properly. The main idea of based on improving the tree pruning method of the original SS-BE to guarantee the high completeness and correctness of the result. In all experiments performed on benchmark data, the proposed solutions outperform the original SS-BE algorithm. Moreover, the proposed algorithms seems to be scalable, as the usage of memory is linearly depended on the number of patterns, and the size of the buffer.","Title: Rough Set Approach to Pattern Extraction from Classifiers\nYear: 2003\n\nAbstract: We discuss the impact of inductive reasoning on the rough set to concept approximation. In inductive reasoning one cannot define inclusion degrees of object neighborhoods directly into the target concepts but only into some neighborhoods relevant to such concepts. Such degrees together with degrees of inclusion of patterns in target concepts make it possible to define outputs of classifiers for new classified objects. We show how among formulas used for classifier construction from decision rules one can search for new patterns relevant for the incremental concept approximation.","Title: Efficient SQL-Querying Method for Data Mining in Large Data Bases\nYear: 1999\n\nAbstract: Data mining can be understood as a process of extraction of knowledge hidden in very large data sets. Often data mining techniques (e.g. discretization or decision tree) are based on searching for an optimal partition of data with respect to some optimization criterion. In this paper, we investigate the problem of optimal binary partition of continuous attribute domain for large data sets stored in relational data bases (RDB). The critical for time complexity of algorithms solving this problem is the number of simple SQL queries like SELECT COUNT FROM ... WHERE attribute BETWEEN ... (related to some interval of attribute values) necessary to construct such partitions. We assume that the answer time for such queries does not depend on the interval length. Using straightforward approach to optimal partition selection (with respect to a given measure), the number of necessary queries is of order O(N), where N is the number of preassumed partitions of the searching space. We show some properties of considered optimization measures, that allow to reduce the size of searching space. Moreover, we prove that using only O(logiV) simple queries, one can construct the partition very close to optimal.","Title: From optimal hyperplanes to optimal decision trees\nYear: 1998\n\nAbstract: We present an optimal hyperplane searching method for decision tables using Genetic Algorithms. This method can be used to construct a decision tree for a given decision table. We also present some properties of the set of hyperplanes determined by our methods and evaluate an upper bound on the depth of the constructed decision tree.","Title: Interactive Method for Semantic Document Indexing Based on Explicit Semantic Analysis.\nYear: 2014\n\nAbstract: In this article we propose a general framework incorporating semantic indexing and search of texts within scientific document repositories. In our approach, a semantic interpreter, which can be seen as a tool for automatic tagging of textual data, is interactively updated based on feedback from the users, in order to improve quality of the tags that it produces. In our experiments, we index our document corpus using the Explicit Semantic Analysis (ESA) method. In this algorithm, an external knowledge base is used to measure relatedness between words and concepts, and those assessments are utilized to assign meaningful concepts to given texts. In the paper, we explain how the weights expressing relations between particular words and concepts can be improved by interaction with users or by employment of expert knowledge. We also present some results of experiments on a document corpus acquired from the PubMed Central repository to show feasibility of our approach.","Title: Granular Floor Plan Representation for Evacuation Modeling.\nYear: 2014\n\nAbstract: In this paper we describe the architecture of a simple evacuation model which is based on a graph representation of the scene. Such graphs are typically constructed using Medial Axis Transform (MAT) or Straight Medial Axis Transform (S-MAT) transformations, the former being a part of the Voronoi diagram (Dirichlet tessellation) of the floor plan. In our work we construct such graphs for floor plans using Voronoi diagram along with the dual Delaunay triangulation of a set of points approximating the scene. Information supplied by Delaunay triangulation complements the graph in two ways: it determines capacities of some paths associated with edges, and provides a bijection between graph vertices and a set of regions forming a partition of the floor plan. We call the representation granular for this reason. In our earlier work we discussed a simplified model coupling a partial behavioral model (accounting for typical pre-movement times) and a traffic model. In this expanded paper, we provide a clearer exposition of the representation of fire scene and briefly discuss the applicability of network flow models (e.g. the Ford-Fulkerson method or the push-relabel method) in our setting.","Title: On semantic evaluation of text clustering algorithms\nYear: 2014\n\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. In previous work we proposed a novel approach to construction of evaluation measure, called SEE (Semantic Evaluation by Exploration), which is an extension of the existing methods such as Rand Index or Normalized Mutual Information. In this paper we present some further extensions as well as some theoretical properties of the of the proposed measure. We illustrate the proposed evaluation method on documents in INFONA document retrieval system. We compare different search result clustering algorithms using the proposed measure.","Title: Adaptive learning for improving semantic tagging of scientific articles\nYear: 2014\n\nAbstract: In this paper we consider a problem of automatic labeling of textual data with concepts explicitly defined in an external knowledge base. We describe our tagging system and we also present a framework for adaptive learning of associations between terms or phrases from the texts and the concepts. Those associations are then utilized by our semantic interpreter, which is based on the Explicit Semantic Analysis (ESA) method, in order to label scientific articles indexed by our SONCA platform. Apart from the description of the learning algorithm, we show a few practical application examples of our system, in which it was used for tagging scientific articles with headings from the MeSH ontology, categories from ACM Computing Classification System and from OECD Fields of Science and Technology Classification.","Title: Rough Set Methods for Large and Spare Data in EAV Format\nYear: 2012\n\nAbstract: In this article we discuss a computationally effective method for computing approximate decision reducts of large data sets. We consider the EAV (entity-attribute-value) which efficiently stores sparse data sets and we propose new implementations of Maximum Discernibility heuristic for data sets represented in this format.","Title: A Semantic Text Retrieval for Indonesian Using Tolerance Rough Sets Models.\nYear: 2015\n\nAbstract: The research of Tolerance Rough Sets Model (TRSM) ever conducted acted in accordance with the rational approach of AI perspective. This article presented studies who complied with the contrary path, i.e. a cognitive approach, for an objective of a modular framework of semantic text retrieval system based on TRSM specifically for Indonesian. In addition to the proposed framework, this article proposes three methods based on TRSM, which are the automatic tolerance value generator, thesaurus optimization, and lexicon-based document representation. All methods were developed by the use of our own corpus, namely ICL-corpus, and evaluated by employing an available Indonesian corpus, called Kompas-corpus. The endeavor of a semantic information retrieval system is the effort to retrieve information and not merely terms with similar meaning. This article is a baby step toward the objective.","Title: Searching for Reductive Attributes in Decision Tables.\nYear: 2015\n\nAbstract: Most decision support systems based on rough set theory are related to the minimal reduct calculation problem, which is NP-hard. This paper investigates the problem of searching for the set of useful attributes that occur in at least one reduct. By complement, this problem is equivalent to searching for the set of redundant attributes, i.e. the attributes that do not occur in any reducts of the given decision table. We show that the considered problem is equivalent to a Sperner system for relational data base system and prove that it can be solved in polynomial time. On the base of these theoretical results, we also propose two different algorithms for elimination of redundant attributes in decision tables.","Title: A Dynamic Packed Approach for Analytic Data Warehouse in Ad-Hoc Queries.\nYear: 2017\n\nAbstract: Brighthouse is a column-oriented data warehouse that supports the compressed databases as well as analytic querying. For the faster query processing, Brighthouse creates packages from the data rows. While the query is resolving, it decompresses only those packages that partially satisfy the condition of the query to avoid accessing all the database. However, Brighthouse used a constant parameter to create packages, this may create incompact packages and lead to large number of packages that are processed in each query. In this paper, at first, we define the task of partitioning data table into blocks as an optimization problem, then discuss the time complexity of the problem and propose an efficient algorithm, which creates dynamically data packages for efficient queries in databases. The experimental results shown the advantage of the proposed approach in package range reduction.","Title: Efficient method for updating class association rules in dynamic datasets with record deletion.\nYear: 2018\n\nAbstract: Association rule mining is an important topic in data mining. The problem is to discover all (or almost all) associations among items in the transaction database that satisfy some user-specified constraints. Usually, the constraints are related to minimal support and minimal confidence. Class association rules (CARs) are a special type of association rules that can be applied for classification problem. Previous research showed that classification based on association rules has higher accuracy than can be achieved with an inductive learning algorithm or C4.5. As such, many methods have been proposed for mining CARs, although these use batch processing. However, datasets are often changed, with records added or/and deleted, and consequently updating CARs is a challenging problem. This paper proposes an efficient method for updating CARs when records are deleted. First, we use an MECR-tree to store nodes for the original dataset. The information in the nodes of this tree are updated based on the deleted records. Second, the concept of pre-large itemsets is used to avoid rescanning the original dataset. Finally, we propose an algorithm to efficiently update and generate CARs. We also analyze the time complexity to show the efficiency of our proposed algorithm. The experimental results show that the proposed method outperforms mining CARs from the dataset after record deletion.","Title: Search Result Clustering Based on Query Context.\nYear: 2015\n\nAbstract: This paper introduces a novel, interactive and exploratory, approach to information retrieval search engines based on clustering. Presented method allows users to change the clustering structure by applying a free-text clustering context query that is treated as a criterion for document-to-cluster allocation. Exploration mechanisms are delivered by redefining the interaction scenario in which the user can interact with data on the level of topic discovery or cluster labeling. In this paper, the presented idea is realized by a graph structure called the Query-Summarize Graph. This data structure is useful in the definition of the similarity measure between the snippets as well as in the snippet clustering algorithm. The experiments on real-world data are showing that the proposed solution has many interesting properties and can be an alternative approach to interactive information retrieval.","Title: On the possibility of correct concept learning in description logics.\nYear: 2018\n\nAbstract: It is well known that any Boolean function in classical propositional calculus can be learned correctly if the training information system is good enough. In this paper, we extend that result for description logics. We prove that any concept in any description logic that extends \\(\\mathcal {ALC}\\) with some features amongst I (inverse roles), \\(Q_k\\) (qualified number restrictions with numbers bounded by a constant k), and \\(\\mathsf {Self}\\) (local reflexivity of a role) can be learned correctly if the training information system (specified as a finite interpretation) is good enough. That is, there exists a learning algorithm such that, for every concept C of those logics, there exists a training information system such that applying the learning algorithm to it results in a concept equivalent to C. For this result, we introduce universal interpretations and bounded bisimulation in description logics and develop an appropriate learning algorithm. We also generalize common types of queries for description logics, introduce interpretation queries, and present some consequences.","Title: Tolerance Rough Set Model and Its Applications in Web Intelligence\nYear: 2013\n\nAbstract: Tolerance Rough Set Model (TRSM) has been introduced as a tool for approximation of hidden concepts in text databases. In recent years, numerous successful applications of TRSM in web intelligence including text classification, clustering, thesaurus generation, semantic indexing, and semantic search, etc., have been proposed. This paper will review the fundamental concepts of TRSM, some of its possible extensions and some typical applications of TRSM in text mining. Moreover, the architecture o a semantic information retrieval system, called SONCA, will be presented to demonstrate the main idea as well as stimulate the further research on TRSM.","Title: Towards VNUMED for Healthcare Research Activities in Vietnam.\nYear: 2019\n\nAbstract: Inspired by MIMIC- III [1], VNUMED is a unified intermediate database of electronic medical records that is being developed in Vietnam. Its purpose is to gather medical records from hospitals, which can be used to support medical research.","Title: Rotation Variance in Graph Convolutional Networks\nYear: 2021\n\nAbstract: Convolution filters in deep convolutional networks display rotation variant behavior. While learned invariant behavior can be partially achieved, this paper shows that current methods of utilizing rotation variant features can be improved by proposing a grid-based graph convolutional network. By performing spectral graph convolutions on features extracted from subareas of images, we are able to ta...","Title: Cellular Automata in Covid-19 prediction\nYear: 2021\n\nAbstract: At the end of 2019 a new coronavirus emerged, turning into a world pandemic. The new coronavirus is called COVID-19. Different countries handled the pandemic differently and our main focus in this article is on Poland. For better counteracting and managing the situation a model for predicting the dynamics of the pandemic is needed. In this article we present a model for simulating future infections taking into account various preventive measures and locations in Poland. We based the model on a two-dimensional cellular automata, with spatial dependencies between regions, different population and size of simulated regions. (C) 2021 The Authors. Published by Elsevier B.V.","Title: A Method for Closed Frequent Subgraph Mining in a Single Large Graph\nYear: 2021\n\nAbstract: Mining frequent subgraphs is an interesting and important problem in the graph mining field, in that mining frequent subgraphs from a single large graph has been strongly developed, and has recently attracted many researchers. Among them, MNI-based approaches are considered as state-of-the-art, such as the GraMi algorithm. Besides frequent subgraph mining (FSM), frequent closed frequent subgraph mining was also developed. This has many practical applications and is a fundamental premise for many studies. This paper proposes the CloGraMi (Closed Frequent Subgraph Mining) algorithm based on GraMi to find all closed frequent subgraphs in a single large graph. Two effective strategies are also developed, the first one is a new level order traversal strategy to quickly determine closed subgraphs in the searching process, and the second is setting a condition for early pruning a large portion of non-closed candidates, both of them aim to reduce the running time as well as the memory requirements, improve the performance of the proposed algorithm. Our experiments are performed on five real datasets (both directed and undirected graphs) and the results show that the running time as well as the memory requirements of our algorithm are significantly better than those of the GraMi-based algorithm.","Title: Feature Selection and Ranking Method based on Intuitionistic Fuzzy Matrix and Rough Sets\nYear: 2022\n\nAbstract: In this paper we propose a novel rough-fuzzy hybridization technique to feature selection and feature ranking problem. The idea is to model the local preference relation between pair of features by intuitionistic fuzzy values and search for a feature ranking that is consistent with those constraints. We apply the techniques used in group decision making where constraints are presented in form of intuitionistic fuzzy preference relation. The proposed method has been illustrated by some simple examples and verified on a benchmark dataset."],"string":"[\n \"Title: Hierarchical Rough Classifiers\\nYear: 2007\\n\\nAbstract: The major applications of rough set theory in data mining are related to the modeling of concepts using rough classifiers,\\n i.e., the algorithms classifying unseen objects into lower or upper approximations of concepts. This paper investigates a\\n class of compound classifiers called multi-level (or hierarchical) rough classifiers (MLRC). We present the most recent issues\\n on the construction of such classifiers from data using concept ontology as an additional domain knowledge. The idea is based\\n on the bottom-up manner to gradually synthesize the multi-layer rough classifier for the complex target concept from the simpler\\n classifiers.We illustrate the proposed method by experiments on real-life data.\",\n \"Title: Learning Sunspot Classification\\nYear: 2006\\n\\nAbstract: Sunspots are the subject of interest to many astronomers and solar physicists. Sunspot observation, analysis and classification form an important part of furthering the knowledge about the Sun. Sunspot classification is a manual and very labor intensive process that could be automated if successfully learned by a machine. This paper presents machine learning approaches to the problem of sunspot classification. The classification scheme attempted was the seven-class Modified Zurich scheme [18]. The data was obtained by processing NASA SOHO/MDI satellite images to extract individual sunspots and their attributes. A series of experiments were performed on the training dataset with an aim of learning sunspot classification and improving prediction accuracy. The experiments involved using decision trees, rough sets, hierarchical clustering and layered learning methods. Sunspots were characterized by their visual properties like size, shape, positions, and were manually classified by comparing extracted sunspots with corresponding active region maps (ARMaps) from the Mees Observatory at the Institute for Astronomy, University of Hawaii.\",\n \"Title: Rough sets and association rule generation\\nYear: 1999\\n\\nAbstract: ASSOCIATION RULE (see [1]) extraction methods have been developed as the main methods for mining of real life data, in particular in Basket Data Analysis. In this paper we present a novel approach to generation of association rules, based on Rough Set and Boolean reasoning methods. Some results presented in this paper has been mentioned in [13, 17]. We will explain them precisely (with full proofs of theorems) in this paper. We show the relationship between the problems of association rule extraction for transaction data and relative reducts (or α-reducts generation) for a decision table. Moreover, the present approach can be used to extract association rules in general form. The experimental results show that the presented methods are quite efficient. Large number of association rules with given support and confidence can be extracted in a short time.\",\n \"Title: A Soft Decision Tree\\nYear: 2002\\n\\nAbstract: Searching for binary partition of attribute domains is an important task in Data Mining, particularly in decision tree methods. The most important advantage of decision tree methods are based on compactness and clearness of presented knowledge and high accuracy of classification. In case of large data tables, the existing decision tree induction methods often show to be inecient in both computation and description aspects. The disadvantage of standard decision tree methods is also their instability, i.e., small deviation of data perhaps cause a total change of decision tree. We present the novel \\\"soft discretization\\\" methods using \\\"soft cuts\\\" instead of traditional \\\"crisp\\\" (or sharp) cuts. This new concept allows to generate more compact and stable decision trees with high classification accuracy. We also present an ecient\",\n \"Title: Lexicon-based Document Representation\\nYear: 2013\\n\\nAbstract: It is a big challenge for an information retrieval system IRS to interpret the queries made by users, particularly because the common form of query consists of very few terms. Tolerance rough sets models TRSM, as an extension of rough sets theory, have demonstrated their ability to enrich document representation in terms of semantic relatedness. However, system efficiency is at stake because the weight vector created by TRSM TRSM-representation is much less sparse. We mapped the terms occurring in TRSM-representation to terms in the lexicon, hence the final representation of a document was a weight vector consisting only of terms that occurred in the lexicon LEX-representation. The LEX-representation can be viewed as a compact form of TRSM-representation in a lower dimensional space and eliminates all informal terms previously occurring in TRSM-vector. With these facts, we may expect a more efficient system. We employed recall and precision commonly used in information retrieval to evaluate the effectiveness of LEX-representation. Based on our examination, we found that the effectiveness of LEX-representation is comparable with TRSM-representation while the efficiency of LEX-representation should be better than the existing TRSM-representation. We concluded that lexicon-based document representation was another alternative potentially used to represent a document while considering semantics. We are tempted to implement the LEX-representation together with linguistic computation, such as tagging and feature selection, in order to retrieve more relevant terms with high weight. With regard to the TRSM method, enhancing the quality of tolerance class is crucial based on the fact that the TRSM method is fully reliant on the tolerance classes. We plan to combine other resources such as Wikipedia Indonesia to generate a better tolerance class.\",\n \"Title: Pattern extraction from data\\nYear: 1998\\n\\nAbstract: Searching for patterns is one of the main goals in data mining. Patterns have important applications in many KDD domains like rule extraction or classification. In this paper we present some methods of rule extraction by generalizing the existing approaches for the pattern problem. These methods, called partition of attribute values or grouping of attribute values, can be applied to decision tables with symbolic value attributes. If data tables contain symbolic and numeric attributes, some of the proposed methods can be used jointly with discretization methods. Moreover, these methods are applicable for incomplete data. The optimization problems for grouping of attribute values are either NP-complete or NP-hard. Hence we propose some heuristics returning approximate solutions for such problems.\",\n \"Title: Rough Set Methods in Approximation of Hierarchical Concepts\\nYear: 2004\\n\\nAbstract: Many learning methods ignore domain knowledge in synthesis of concept approximation. We propose to use hierarchical schemes for learning approximations of complex concepts from experimental data using inference diagrams based on domain knowledge. Our solution is based on the rough set and rough mereological approaches. The effectiveness of the proposed approach is performed and evaluated on artificial data sets generated by a traffic road simulator.\",\n \"Title: RSCTC'2010 discovery challenge: mining DNA microarray data for medical diagnosis and treatment\\nYear: 2010\\n\\nAbstract: RSCTC'2010 Discovery Challenge was a special event of Rough Sets and Current Trends in Computing conference. The challenge was organized in the form of an interactive on-line competition, at TUNEDIT.org platform, in days between Dec 1, 2009 and Feb 28, 2010. The task was related to feature selection in analysis of DNA microarray data and classification of samples for the purpose of medical diagnosis or treatment. Prizes were awarded to the best solutions. This paper describes organization of the competition and the winning solutions.\",\n \"Title: Fast split selection method and its application in decision tree construction from large databases\\nYear: 2005\\n\\nAbstract: We present an efficient method for decision tree construction from large data sets, which are assumed to be stored in database servers, and be accessible by SQL queries. The proposed method minimizes the number of simple queries necessary to search for the best splits (cut points) by employing \\\"divide and conquer\\\" search strategy. To make it possible, we develop some novel evaluation measures which are defined on intervals of attribute domains. Proposed measures are necessary to estimate the quality of the best cut in a given interval. We propose some applications of the presented approach in discretization and construction of \\\"soft decision tree\\\", which is a novel classifier model.\",\n \"Title: An Algorithm for Tolerance Value Generator in Tolerance Rough Sets Model.\\nYear: 2012\\n\\nAbstract: The Tolerance Rough Sets Model (TRSM) is a tool to model document in text mining. Generation of a document representation based on TRSM basically depends on tolerance classes of terms which are created by setting up a tolerance value. Despite the fact that tolerance value is critical in TRSM, the manual process of setting this value is an exhaustive task. We conducted a study on our own corpus and were supported by two human experts when constructing the training data. We came up with a novel algorithm to generate tolerance value automatically from a set of training data. The heart of our algorithm is measuring the distance between document representation calculated using TFIDF weighting scheme and document representation yielded by TRSM both in reduced dimensional space generated by Singular Value Decomposition (SVD). In spite of the result, we recognize that further study is significant, i.e. to set up some properties (the size of training data and rank of SVD) as well as evaluating the algorithm in real data and scenario.\",\n \"Title: Knowledge discovery by relation approximation: a rough set approach\\nYear: 2006\\n\\nAbstract: In recent years, rough set theory [1] has attracted attention of many researchers and practitioners all over the world, who have contributed essentially to its development and applications. With many practical and interesting applications rough set approach seems to be of fundamental importance to AI and cognitive sciences, especially in the areas of machine learning, knowledge acquisition, decision analysis, knowledge discovery from databases, expert systems, inductive reasoning and pattern recognition [2]\",\n \"Title: A method of Web search result clustering based on rough sets\\nYear: 2005\\n\\nAbstract: Due to the enormous size of the Web and low precision of user queries, finding the right information from the Web can be difficult if not impossible. One approach that tries to solve this problem is using clustering techniques for grouping similar document together in order to facilitate presentation of results in more compact form and enable thematic browsing of the results set. The main problem of many Web search result (snippet) clustering algorithm is based on the poor vector representation of snippets. In this paper, we present a method of snippet representation enrichment using tolerance rough set model. We applied the proposed method to construct a rough set based search result clustering algorithm and compared it with other recent methods.\",\n \"Title: Investigating the effectiveness of thesaurus generated using tolerance rough set model\\nYear: 2011\\n\\nAbstract: We considered the tolerance matrix generated using tolerance rough set model as a kind of an associative thesaurus. The effectiveness of the thesaurus was measured using performance measures commonly used in information retrieval, recall and precision, where they were used for the terms rather than documents. A corpus consists of keywords defined as highly related with particular topic by human experts become the ground truth of this study. Analysis was conducted based on comparison values of all available sets created. Above all findings, this paper was thought as the fundamental basis that generating an automatic thesaurus using rough sets theory is a promising way. We also mentioned some directions for future study.\",\n \"Title: Approximated measures in construction of decision trees from large databases\\nYear: 2003\\n\\nAbstract: We present an efficient method for decision tree construction from large data set, which is assumed to be stored in some database server, and to be accessible by SQL queries. We develop a decision tree construction method, which minimizes the total time of data transmission between client and server. Our method, based on divide and conqurer search strategy, minimizes the number of simple queries necessary to search for the best cuts. To make it possible, we develop some, approximate measures, defined on intervals of attribute values, to evaluate the chance that the best cut belongs to the given interval. We propose some applications of the presented approach in discretization and construction of soft decision tree, which is a novel classifier model.\",\n \"Title: Metric Based Attribute Reduction in Incomplete Decision Tables.\\nYear: 2013\\n\\nAbstract: Metric technique has recently been applied to solve such data mining problems as classification, clustering, feature selection, decision tree construction. In this paper, we apply metric technique to solve a attribute reduction problem of incomplete decision tables in rough set theory. We generalize Liang entropy in incomplete information systems and investigate its properties. Based on the generalized Liang entropy, we establish a metric between coverings and study its properties for attribute reduction. Consequently, we propose a metric based attribute reduction method in incomplete decision tables and perform experiments on UCI data sets. The experimental results show that metric technique is an effective method for attribute reduction in incomplete decision tables.\",\n \"Title: Scalable Classification Method Based on Rough Sets\\nYear: 2002\\n\\nAbstract: The existing rough set based methods are not applicable for large data set because of the high time and space complexity and the lack of scalability. We present a classification method, which is equivalent to rough set based classification methods, but is scalable and applicable for large data sets. The proposed method is based on lazy learning idea [2] and Apriori algorithm for sequent item-set approaches [1]. In this method the set of decision rules matching the new object is generated directly from training set. Accept classification task, this method can be used for adaptive rule generation system where data is growing up in time.\",\n \"Title: Approximate Reducts and Association Rules - Correspondence and Complexity Results\\nYear: 1999\\n\\nAbstract: . We consider approximate versions of fundamental notions oftheories of rough sets and association rules. We analyze the complexityof searching for ff-reducts, understood as subsets discerning "ff-almost"objects from different decision classes, in decision tables. We present howoptimal approximate association rules can be derived from data by usingheuristics for searching for minimal ff-reducts. NP-hardness of the problemof finding optimal approximate association rules is shown as...\",\n \"Title: Rough Set Approach to KDD (Extended Abstract)\\nYear: 2008\\n\\nAbstract: This tutorial is a survey on rough set theory and some of its applications in Knowledge Discovery from Databases (KDD). It\\n will also cover the practice guide to analysis of different real life problems using rough set methods as well as the presentation\\n of Rough Set Exploration System (RSES) what can be treated as a preliminary material for the main conference and associated\\n workshops.\\n \\n Rough Set theory was introduced by Zdzisław Pawlak in the early 80’s and has currently reached a level of high visibility\\n and maturity [3,2,4,5,6] Originally, rough sets, whose main philosophy is based simply on indiscernibility and discernibility\\n of objects, were presented as an approach to concept approximation under uncertainty. This brilliantly simple idea has been\\n successively expanded in the last twenty years. Many effective methods for data analysis have been developed on the basis\\n of rough set theory.\",\n \"Title: Rough set approach to sunspot classification problem\\nYear: 2005\\n\\nAbstract: This paper presents an application of hierarchical learning method based rough set theory to the problem of sunspot classification from satellite images. The Modified Zurich classification scheme [3] is defined by a set of rules containing many complicated and unprecise concepts, which cannot be determined directly from solar images. The idea is to represent the domain knowledge by an ontology of concepts – a treelike structure that describes the relationship between the target concepts, intermediate concepts and attributes. We show that such ontology can be constructed by a decision tree algorithm and demonstrate the proposed method on the data set containing sunspot extracted from satellite images of solar disk.\",\n \"Title: Approximate boolean reasoning approach to rough sets and data mining\\nYear: 2005\\n\\nAbstract: Many problems in rough set theory have been successfully solved by boolean reasoning (BR) approach. The disadvantage of this elegant methodology is based on its high space and time complexity. In this paper we present a modified BR approach that can overcome those difficulties. This methodology is called the approximate boolean reasoning (ABR) approach. We summarize some most recent applications of ABR approach in development of new efficient algorithms in rough sets and data mining.\",\n \"Title: Boolean Reasoning Scheme with Some Applications in Data Mining\\nYear: 1999\\n\\nAbstract: We present a general encoding scheme for a wide class of problems (including among others such problems like data reduction, feature selection, feature extraction, decision rules generation, pattern extraction from data or conflict resolution in multi-agent systems) and we show how to combine it with a propositional (Boolean) reasoning to develop efficient heuristics searching for (approximate) solutions of these problems. We illustrate our approach by examples, we show some experimental results and compare them with those reported in literature. We also show that association rule generation is strongly related with reduct approximation.\",\n \"Title: Decomposition of Task Specification Problems\\nYear: 1999\\n\\nAbstract: . We consider a synthesis of complex objects by multi-agentsystem based on rough mereological approach. Any agent can producecomplex objects from parts obtained from his sub-agents using somecomposition rules. Agents are equipped with decision tables describing(partial) specifications of their synthesis tasks. We investigate some problemsof searching for optimal task specifications for sub-agents havingtask specification for a super-agent. We propose a decomposition schemeconsistent with ...\",\n \"Title: Bisimulation-Based Concept Learning in Description Logics\\nYear: 2013\\n\\nAbstract: Concept learning in description logics (DLs) is similar to binary classification in traditional machine learning. The difference is that in DLs objects are described not only by attributes but also by binary relationships between objects. In this paper, we develop the first bisimulation-based method of concept learning in DLs for the following setting: given a knowledge base KB in a DL, a set of objects standing for positive examples and a set of objects standing for negative examples, learn a concept C in that DL such that the positive examples are instances of C w.r.t. KB, while the negative examples are not instances of C w.r.t. KB. We also prove soundness of our method and investigate its C-learnability.\",\n \"Title: Neural Networks Design: Rough Set Approach to Continuous Data\\nYear: 1997\\n\\nAbstract: . The construction of neural network based on decision rulesgenerated by rough set methods is given. Analogies between neural networksemantics and rough set approach to continuous data are pointedout. General framework states the initial point for such applications like,e.g., tuning decision rules by neural network learning process.1 IntroductionThe task of dealing with real-valued datasets seems to be one of key issues indecision support systems. Many approaches have been...\",\n \"Title: An Approach to Pattern Recognition Based on Hierarchical Granular Computing\\nYear: 2013\\n\\nAbstract: This paper summarizes the some of the recent developments in the area of application of rough sets and granular computing in hierarchical learning. We present the general framework of rough set based hierarchical learning. In particular, we investigate several strategies of choosing the appropriate learning algorithms for first level concepts as well as the learning methods for the intermediate concepts. We also propose some techniques for embedding the domain knowledge into the granular, layered learning process in order to improve the quality of hierarchical classifiers. This idea, which has been envisioned and developed by professor Andrzej Skowron over the last 10 years, shows to be very efficient in many practical applications. Throughout the article, we illustrate the proposed methodology with three case studies in the area of pattern recognition. The studies demonstrate the viability of this approach for such problems as: sunspot classification, hand-written digit recognition, and car identification.\",\n \"Title: A bisimulation-based method of concept learning for knowledge bases in description logics\\nYear: 2012\\n\\nAbstract: We develop the first bisimulation-based method of concept learning, called BBCL, for knowledge bases in description logics (DLs). Our method is formulated for a large class of useful DLs, with well-known DLs like ALC, SHIQ, SHOIQ, SROIQ. As bisimulation is the notion for characterizing indis-cernibility of objects in DLs, our method is natural and very promising.\",\n \"Title: On Learning of Sunspot Classification\\nYear: 2004\\n\\nAbstract: This paper describes automatic sunspot recognition and classification from satellite images. Some experimental results on learning sunspot classification using data mining techniques are presented. The classification scheme used was the seven-class Modified Zurich scheme. Daily images of the solar disk were taken from the NASA SOHO satellite's MDI instrument and sunspots extracted using image processing techniques. Two data mining tools, WEKA and RSES, were used for learning sunspot classification. In the training dataset sunspots were manually classified by comparing extracted sunspots with corresponding active region maps.\",\n \"Title: Boolean Reasoning for Feature Extraction Problems\\nYear: 1997\\n\\nAbstract: . We recall several applications of Boolean reasoning for featureextraction and we propose an approach based on Boolean reasoningfor new feature extraction from data tables with symbolic (nominal, qualitative)attributes. New features are of the form a 2 V , where V ` Vaand Va is the set of values of attribute a. We emphasize that Booleanreasoning is also a good framework for complexity analysis of the approximatesolutions of the discussed problems.1 Introduction"Feature Extraction"...\",\n \"Title: Semantic explorative evaluation of document clustering algorithms\\nYear: 2013\\n\\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. We propose a novel approach to construction of evaluation measure, which is based on the Minimal Description Length (MDL) principle. In fact this proposed measure, called SEE (Semantic Evaluation by Exploration), is an improvement of the existing evaluation methods such as Rand Index or Normalized Mutual Information. It fixes some of weaknesses of the original methods. We illustrate the proposed evaluation method on the freely accessible biomedical research articles from Pubmed Central (PMC). Many articles from Pubmed Central are annotated by the experts using Medical Subject Headings (MeSH) thesaurus. This paper is a part of the research on designing and developing a dialog-based semantic search engine for SONCA system which is a part of the SYNAT project. We compare different semantic techniques for search result clustering using the proposed measure.\",\n \"Title: On Scalability of Rough Set Methods\\nYear: 2010\\n\\nAbstract: This paper presents some recent results of the research on the scalability of rough set based classification methods. The proposed solution is based on the close relationship between reduct calculation problem in rough set theory and association rule generation problem. This is a continuation of our previous results (see, e.g. [10] [11]). In this paper, the set of decision rules satisfying the test object is generated directly from the training data set. To make it scalable, we adopted the idea of the FP-growth algorithm for frequent item-sets [7], [6]. The experimental results on some benchmark data sets are showing the ability of the proposed solution to process a growing data sets.\",\n \"Title: Enhancing search result clustering with semantic indexing\\nYear: 2012\\n\\nAbstract: Semantic search results clustering is one of the most wanted functionalities of many information retrieval systems including general web search engines as well as domain specific article portals or digital libraries. It may advice the users to describe the need for information in a more precise way. In this paper, we discuss a framework of document description extension which utilizes domain knowledge and semantic similarity. Our idea is based on application of Tolerance Rough Set Model, semantic information extracted from source text and domain ontology to approximate concepts associated with documents and to enrich the vector representation. Some document representation models including document meta-data, citations and semantic information build using MeSH ontology. We compare those models in a search result clustering problem over the freely accessed biomedical research articles from Pubmed Cetral (PMC) portal. The experimental results are showing the advantages of the proposed models.\",\n \"Title: Layered Learning for Concept Synthesis\\nYear: 2004\\n\\nAbstract: We present a hierarchical scheme for synthesis of concept approximations based on given data and domain knowledge. We also propose a solution, founded on rough set theory, to the problem of constructing the approximation of higher level concepts by composing the approximation of lower level concepts. We examine the effectiveness of the layered learning approach by comparing it with the standard learning approach. Experiments are carried out on artificial data sets generated by a road traffic simulator.\",\n \"Title: On Efficient Construction of Decision Trees from Large Databases\\nYear: 2000\\n\\nAbstract: The main taskin decision tree construction algorithms is to find the “best partition” of the set of objects. In this paper,\\n we investigate the problem of optimal binary partition of continuous attribute for large data sets stored in relational databases. The critical for time complexity of algorithms solving this problem is the number of simple SQL queries necessary to construct\\n such partitions. The straightforward approach to optimal partition selection needs at least O(N) queries, where N is the number of pre-assumed partitions of the searching space. We show some properties of optimization measures related\\n to discernibility between objects, that allow to construct the partition very close to optimal using only O(logN) simple queries.\",\n \"Title: Discretization Problem for Rough Sets Methods\\nYear: 1998\\n\\nAbstract: We study the relationship between reduct problem in Rough Sets theory and the problem of real value attribute discretization. We consider the problem of searching for a minimal set of cuts on attribute domains that preserves discernibility of objects with respect to any chosen attributes subset of cardinality s (where s is a parameter given by a user). Such a discretization procedure assures that one can keep all reducts consisting of at least s attributes. We show that this optimization problem is NP-hard and it is interesting to find efficient heuristics for solving this problem.\",\n \"Title: (No) Sql Platform For Scalable Semantic Processing Of Fast Growing Document Repositories\\nYear: 2012\\n\\nAbstract: Large volumes of scientific data require specific storage and indexing solutions to maximize the effectiveness of searches. Semantic indexing algorithms use domain knowledge to group and rank sets of objects of interest, such as publications, scientists, institutes, and scientific concepts. Their implementation is often based on massively parallel solutions employing NoSQL platforms, although different types of semantic processing operations should be scaled with respect to the growing volumes of scientific information using different database methodologies [1].\",\n \"Title: On c-learnability in description logics\\nYear: 2012\\n\\nAbstract: We prove that any concept in any description logic that extends $\\\\mathcal{ALC}$ with some features amongst I (inverse), Qk (quantified number restrictions with numbers bounded by a constant k), Self (local reflexivity of a role) can be learnt if the training information system is good enough. That is, there exists a learning algorithm such that, for every concept C of those logics, there exists a training information system consistent with C such that applying the learning algorithm to the system results in a concept equivalent to C.\",\n \"Title: On elimination of redundant attributes in decision tables\\nYear: 2012\\n\\nAbstract: Most decision support systems based on rough set theory are related to the minimal reduct calculation problem, which is NP-hard. This paper investigates the problem of searching for the set of useful attributes that occur in at least one reduct. By compliment, this problem is equivalent to searching for the set of redundant attributes, i.e. the attributes that do not occur in any reducts of the given decision table. We show that the considered problem is equivalent to a Sperner system for relational data base system and prove that it can be solved in polynomial time. On the base of these theoretical results, we also propose some algorithms for elimination of redundant attributes in decision tables.\",\n \"Title: On the Decision Table with Maximal Number of Reducts\\nYear: 2003\\n\\nAbstract: Searching for reducts is a basic problem for many rough set methods like rule induction, classification, etc., Many of them can not be realized in exact way because of existing possibly exponential number of (relative) reducts in decision tables. In this paper we investigate properties of the most malicious decision tables, i.e., tables with maximal number of reducts. We show that in such systems, the number of objects must be also exponential. The presented method is based on Boolean reasoning approach.\",\n \"Title: Semantic Evaluation of Text Clustering.\\nYear: 2014\\n\\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. We propose a novel approach to construction of evaluation measure, called SEE (Semantic Evaluation by Exploration), which is an improvement of the existing methods such as Rand Index or Normalized Mutual Information. We illustrate the proposed evaluation method on the freely accessible biomedical research articles from Pubmed Central (PMC). Many articles from Pubmed Central are annotated by the experts using Medical Subject Headings (MeSH) thesaurus. We compare different semantic techniques for search result clustering using the proposed measure.\",\n \"Title: Scalable Methods in Rough Sets\\nYear: 2010\\n\\nAbstract: In this paper we investigate the scalability features of rough set based methods in the context of their applicability in knowledge discovery from databases (KDD) and data mining. We summarize some previously known scalable methods and present one of the latest scalable rough set classifiers. The proposed solution is based on the relationship between rough sets and association discovering methods, which has been described in our previous papers [10] [11]. In this paper, the set of decision rules satisfying the test object is generated directly from the training data set. To make it scalable, we adopted the idea of the FP-growth algorithm for frequent item-sets [7], [6]. The proposed method can be applied in construction of incremental rule-based classification system for stream data.\",\n \"Title: Semantic analytics of pubmed content\\nYear: 2011\\n\\nAbstract: We present an architecture aimed at semantic search and synthesis of information acquired from the document repositories. The proposed framework is expected to provide domain knowledge interfaces enabling the internally implemented algorithms to identify relationships between documents, researchers, institutions, as well as concepts extracted from various types of knowledge bases. The framework should be scalable with respect to data volumes, diversity of analytic processes, and the speed of search. In this paper, we investigate these requirements for the case of medical publications gathered in PubMed.\",\n \"Title: Text Classification Using Lattice Machine\\nYear: 1999\\n\\nAbstract: A novel approach to supervised learning, called Lattice Machine, was proposed in [5]. In the Lattice Machine, it was assumed that data are structured as relations. In this paper we investigate\\n the application of the Lattice Machine in the area of text classification, where textual data are unstructured. We represent\\n a set of textual documents as a collection of Boolean feature vectors, where each vector corresponds to one document and each\\n entry in a tuple indicates whether a particular term appears in the document. This is a common representation of textual documents.\\n We show that using this representation, the Lattice Machine’s operations are simply set theoretic operations. In particular,\\n the lattice sum operation is simply set intersection and the ordering relationship is simply set inclusion. Experiments show\\n that the Lattice Machine, under this configuration, is quite competitive with state-of-the-art learning algorithms for text\\n classification.\",\n \"Title: Situation Identification by Unmanned Aerial Vehicle\\nYear: 2000\\n\\nAbstract: An approach to a multi-facet task of situation identification by Unmanned Aerial Vehicle (UAV) is presented. The concept of multi-layered identification system based on soft computing approach to reasoning with incomplete, imprecise or vague information is discussed.\",\n \"Title: Approximate Boolean Reasoning: Foundations and Applications in Data Mining\\nYear: 2006\\n\\nAbstract: Since its introduction by George Boole during the mid-1800s, Boolean algebra has become an important part of the lingua franca of mathematics, science, engineering, and research in artificial intelligence, machine learning and data mining. The Boolean reasoning approach has manifestly become a powerful tool for designing effective and accurate solutions for many problems in decision-making and approximate reasoning optimization. In recent years, Boolean reasoning has become a recognized technique for developing many interesting concept approximation methods in rough set theory. The problem considered in this paper is the creation of a general framework for concept approximation. The need for such a general framework arises in machine learning and data mining. This paper presents a solution to this problem by introducing a general framework for concept approximation which combines rough set theory, Boolean reasoning methodology and data mining. This general framework for approximate reasoning is called Rough Sets and Approximate Boolean Reasoning (RSABR). The contribution of this paper is the presentation of the theoretical foundation of RSABR as well as its application in solving many data mining problems and knowledge discovery in databases (KDD) such as feature selection, feature extraction, data preprocessing, classification of decision rules and decision trees, association analysis.\",\n \"Title: On Efficient Handling of Continuous Attributes in Large Data Bases\\nYear: 2001\\n\\nAbstract: Some data mining techniques, like discretization of continuous attributes or decision tree induction, are based on searching for an optimal partition of data with respect to some optimization criteria. We investigate the problem of searching for optimal binary partition of continuous attribute domain in case of large data sets stored in relational data bases (RDB). The critical for time complexity of algorithms solving this problem is the number of I/O database operations necessary to construct such partitions. In our approach the basic operators are defined by queries on the number of objects characterized by means of real value intervals of continuous attributes. We assume the answer time for such queries does not depend on the interval length. The straightforward approach to the optimal partition selection (with respect to a given measure) requires O(N) basic queries, where N is the number of preassumed partition parts in the searching space. We show properties of the basic optimization measures making possible to reduce the size of searching space. Moreover, we prove that using only O(log N) simple queries, one can construct a partition very close to optimal.\",\n \"Title: Searching for Features Defined by Hyperplanes\\nYear: 1996\\n\\nAbstract: . We consider decision tables with real value conditional attributesand we present a method for extraction of features defined byhyperplanes in a multi-dimensional affine space. These new features areoften more relevant for object classification than the features definedby hyperplanes parallel to axes. The method generalizes an approachpresented in [18] in case of hyperplanes not necessarily parallel to theaxes. We propose genetic strategies searching for hyperplanes discerningbetween...\",\n \"Title: IEEE ICDM 2010 Contest: TomTom Traffic Prediction for Intelligent GPS Navigation\\nYear: 2010\\n\\nAbstract: In this foreword, we summarize the IEEE ICDM 2010 Contest: “TomTom Traffic Prediction for Intelligent GPS Navigation”. The challenge was held between Jun 22, 2010 and Sep 7, 2010 as an interactive on-line competition, using the TunedIT platform (http://tunedit.org). We present the scope of the ICDM contest series in general, the scope of this year’s contest, description of its tasks, statistics about participation, details about the TunedIT platform and the Traffic Simulation Framework. A detailed description of winning solutions is part of this proceeding series.\",\n \"Title: Analysis of Image Sequences for the Unmanned Aerial Vehicle\\nYear: 2001\\n\\nAbstract: A method for extracting relevant information from image sequence data is presented. The image sequences, being output of video system of the Unmanned Aerial Vehicle, are analysed with use of EM-clustering techniques and Rough Set based methods. The possibilities of construction of an automated system for recognition/identification of cars on the road, on the basis of colour-related data are discussed.\",\n \"Title: A tolerance rough set approach to clustering web search results\\nYear: 2004\\n\\nAbstract: Two most popular approaches to facilitate searching for information on the web are represented by web search engine and web\\n directories. Although the performance of search engines is improving every day, searching on the web can be a tedious and\\n time-consuming task due to the huge size and highly dynamic nature of the web. Moreover, the user’s “intention behind the\\n search” is not clearly expressed which results in too general, short queries. Results returned by search engine can count\\n from hundreds to hundreds of thousands of documents.\\n \\n \\n One approach to manage the large number of results is clustering. Search results clustering can be defined as a process of automatical grouping search results into to thematic groups. However, in contrast to traditional document clustering, clustering of search results are done on-the-fly (per user query\\n request) and locally on a limited set of results return from the search engine. Clustering of search results can help user\\n navigate through large set of documents more efficiently. By providing concise, accurate description of clusters, it lets\\n user localizes interesting document faster.\\n \\n \\n \\n In this paper, we proposed an approach to search results clustering based on Tolerance Rough Set following the work on document\\n clustering [4,3]. Tolerance classes are used to approximate concepts existed in documents. The application of Tolerance Rough\\n Set model in document clustering was proposed as a way to enrich document and cluster representation with the hope of increasing\\n clustering performance.\",\n \"Title: Granular Computing: A Rough Set Approach\\nYear: 2001\\n\\nAbstract: We discuss information granule calculi as a basis of granular computing. They are defined by constructs like information granules, basic relations of inclusion and closeness between information granules as well as operations on them. The exact interpretation between granule languages of different information sources (agents) often does not exist. Hence (rough) inclusion and closeness of granules are considered instead of their equality. Examples of all the basic constructs of information granule calculi are presented. The construction of more complex information granules is described by expressions called terms. We discuss the synthesis problem of robust terms, i.e., descriptions of information granules, satisfying a given specification in a satisfactory degree. We also present a method for synthesis of information granules represented by robust terms (approximate schemes of reasoning) by means of decomposition of specifications for such granules. The discussed problems of granular computing are of special importance for many applications, in particular related to spatial reasoning as well as to knowledge discovery and data mining.\",\n \"Title: Unsupervised Similarity Learning from Textual Data\\nYear: 2012\\n\\nAbstract: This paper presents a research on the construction of a new unsupervised model for learning a semantic similarity measure from text corpora. Two main components of the model are a semantic interpreter of texts and a similarity function whose properties are derived from data. The first one associates particular documents with concepts defined in a knowledge base corresponding to the topics covered by the corpus. It shifts the representation of a meaning of the texts from words that can be ambiguous to concepts with predefined semantics. With this new representation, the similarity function is derived from data using a modification of the dynamic rule-based similarity model, which is adjusted to the unsupervised case. The adjustment is based on a novel notion of an information bireduct having its origin in the theory of rough sets. This extension of classical information reducts is used in order to find diverse sets of reference documents described by diverse sets of reference concepts that determine different aspects of the similarity. The paper explains a general idea of the approach and also gives some implementation guidelines. Additionally, results of some preliminary experiments are presented in order to demonstrate usefulness of the proposed model.\",\n \"Title: Concept Learning for Description Logic-Based Information Systems\\nYear: 2012\\n\\nAbstract: The work [1] by Nguyen and Szalas is a pioneering one that uses bisimulation for machine learning in the context of description logics. In this paper we generalize and extend their concept learning method [1] for description logic-based information systems. We take attributes as basic elements of the language. Each attribute may be discrete or numeric. A Boolean attribute is treated as a concept name. This approach is more general and much more suitable for practical information systems based on description logic than the one of [1]. As further extensions we allow also data roles and the concept constructors \\\"functionality\\\" and \\\"unquantified number restrictions\\\". We formulate and prove an important theorem on basic selectors. We also provide new examples to illustrate our approach.\",\n \"Title: Sequential pattern mining from stream data\\nYear: 2011\\n\\nAbstract: Sequential Pattern Mining, briefly SPM, is an interesting issue in Data Mining that can be applied for temporal or time series data. This paper is related to SPM algorithms that can work with stream data. We present three new stream SPM methods, called SS-BE2, SS-LC and SS-LC2, which are the extensions of SS-BE. The proposed methods, similarly to SS-BE, are dealing with fixed-sized batches using PrefixSpan algorithm, and the critical problem in each step is how to store the huge amount of candidate patterns, and how to select the frequent patterns properly. The main idea of based on improving the tree pruning method of the original SS-BE to guarantee the high completeness and correctness of the result. In all experiments performed on benchmark data, the proposed solutions outperform the original SS-BE algorithm. Moreover, the proposed algorithms seems to be scalable, as the usage of memory is linearly depended on the number of patterns, and the size of the buffer.\",\n \"Title: Rough Set Approach to Pattern Extraction from Classifiers\\nYear: 2003\\n\\nAbstract: We discuss the impact of inductive reasoning on the rough set to concept approximation. In inductive reasoning one cannot define inclusion degrees of object neighborhoods directly into the target concepts but only into some neighborhoods relevant to such concepts. Such degrees together with degrees of inclusion of patterns in target concepts make it possible to define outputs of classifiers for new classified objects. We show how among formulas used for classifier construction from decision rules one can search for new patterns relevant for the incremental concept approximation.\",\n \"Title: Efficient SQL-Querying Method for Data Mining in Large Data Bases\\nYear: 1999\\n\\nAbstract: Data mining can be understood as a process of extraction of knowledge hidden in very large data sets. Often data mining techniques (e.g. discretization or decision tree) are based on searching for an optimal partition of data with respect to some optimization criterion. In this paper, we investigate the problem of optimal binary partition of continuous attribute domain for large data sets stored in relational data bases (RDB). The critical for time complexity of algorithms solving this problem is the number of simple SQL queries like SELECT COUNT FROM ... WHERE attribute BETWEEN ... (related to some interval of attribute values) necessary to construct such partitions. We assume that the answer time for such queries does not depend on the interval length. Using straightforward approach to optimal partition selection (with respect to a given measure), the number of necessary queries is of order O(N), where N is the number of preassumed partitions of the searching space. We show some properties of considered optimization measures, that allow to reduce the size of searching space. Moreover, we prove that using only O(logiV) simple queries, one can construct the partition very close to optimal.\",\n \"Title: From optimal hyperplanes to optimal decision trees\\nYear: 1998\\n\\nAbstract: We present an optimal hyperplane searching method for decision tables using Genetic Algorithms. This method can be used to construct a decision tree for a given decision table. We also present some properties of the set of hyperplanes determined by our methods and evaluate an upper bound on the depth of the constructed decision tree.\",\n \"Title: Interactive Method for Semantic Document Indexing Based on Explicit Semantic Analysis.\\nYear: 2014\\n\\nAbstract: In this article we propose a general framework incorporating semantic indexing and search of texts within scientific document repositories. In our approach, a semantic interpreter, which can be seen as a tool for automatic tagging of textual data, is interactively updated based on feedback from the users, in order to improve quality of the tags that it produces. In our experiments, we index our document corpus using the Explicit Semantic Analysis (ESA) method. In this algorithm, an external knowledge base is used to measure relatedness between words and concepts, and those assessments are utilized to assign meaningful concepts to given texts. In the paper, we explain how the weights expressing relations between particular words and concepts can be improved by interaction with users or by employment of expert knowledge. We also present some results of experiments on a document corpus acquired from the PubMed Central repository to show feasibility of our approach.\",\n \"Title: Granular Floor Plan Representation for Evacuation Modeling.\\nYear: 2014\\n\\nAbstract: In this paper we describe the architecture of a simple evacuation model which is based on a graph representation of the scene. Such graphs are typically constructed using Medial Axis Transform (MAT) or Straight Medial Axis Transform (S-MAT) transformations, the former being a part of the Voronoi diagram (Dirichlet tessellation) of the floor plan. In our work we construct such graphs for floor plans using Voronoi diagram along with the dual Delaunay triangulation of a set of points approximating the scene. Information supplied by Delaunay triangulation complements the graph in two ways: it determines capacities of some paths associated with edges, and provides a bijection between graph vertices and a set of regions forming a partition of the floor plan. We call the representation granular for this reason. In our earlier work we discussed a simplified model coupling a partial behavioral model (accounting for typical pre-movement times) and a traffic model. In this expanded paper, we provide a clearer exposition of the representation of fire scene and briefly discuss the applicability of network flow models (e.g. the Ford-Fulkerson method or the push-relabel method) in our setting.\",\n \"Title: On semantic evaluation of text clustering algorithms\\nYear: 2014\\n\\nAbstract: In this paper, we investigate the problem of quality analysis of clustering results using semantic annotations given by experts. In previous work we proposed a novel approach to construction of evaluation measure, called SEE (Semantic Evaluation by Exploration), which is an extension of the existing methods such as Rand Index or Normalized Mutual Information. In this paper we present some further extensions as well as some theoretical properties of the of the proposed measure. We illustrate the proposed evaluation method on documents in INFONA document retrieval system. We compare different search result clustering algorithms using the proposed measure.\",\n \"Title: Adaptive learning for improving semantic tagging of scientific articles\\nYear: 2014\\n\\nAbstract: In this paper we consider a problem of automatic labeling of textual data with concepts explicitly defined in an external knowledge base. We describe our tagging system and we also present a framework for adaptive learning of associations between terms or phrases from the texts and the concepts. Those associations are then utilized by our semantic interpreter, which is based on the Explicit Semantic Analysis (ESA) method, in order to label scientific articles indexed by our SONCA platform. Apart from the description of the learning algorithm, we show a few practical application examples of our system, in which it was used for tagging scientific articles with headings from the MeSH ontology, categories from ACM Computing Classification System and from OECD Fields of Science and Technology Classification.\",\n \"Title: Rough Set Methods for Large and Spare Data in EAV Format\\nYear: 2012\\n\\nAbstract: In this article we discuss a computationally effective method for computing approximate decision reducts of large data sets. We consider the EAV (entity-attribute-value) which efficiently stores sparse data sets and we propose new implementations of Maximum Discernibility heuristic for data sets represented in this format.\",\n \"Title: A Semantic Text Retrieval for Indonesian Using Tolerance Rough Sets Models.\\nYear: 2015\\n\\nAbstract: The research of Tolerance Rough Sets Model (TRSM) ever conducted acted in accordance with the rational approach of AI perspective. This article presented studies who complied with the contrary path, i.e. a cognitive approach, for an objective of a modular framework of semantic text retrieval system based on TRSM specifically for Indonesian. In addition to the proposed framework, this article proposes three methods based on TRSM, which are the automatic tolerance value generator, thesaurus optimization, and lexicon-based document representation. All methods were developed by the use of our own corpus, namely ICL-corpus, and evaluated by employing an available Indonesian corpus, called Kompas-corpus. The endeavor of a semantic information retrieval system is the effort to retrieve information and not merely terms with similar meaning. This article is a baby step toward the objective.\",\n \"Title: Searching for Reductive Attributes in Decision Tables.\\nYear: 2015\\n\\nAbstract: Most decision support systems based on rough set theory are related to the minimal reduct calculation problem, which is NP-hard. This paper investigates the problem of searching for the set of useful attributes that occur in at least one reduct. By complement, this problem is equivalent to searching for the set of redundant attributes, i.e. the attributes that do not occur in any reducts of the given decision table. We show that the considered problem is equivalent to a Sperner system for relational data base system and prove that it can be solved in polynomial time. On the base of these theoretical results, we also propose two different algorithms for elimination of redundant attributes in decision tables.\",\n \"Title: A Dynamic Packed Approach for Analytic Data Warehouse in Ad-Hoc Queries.\\nYear: 2017\\n\\nAbstract: Brighthouse is a column-oriented data warehouse that supports the compressed databases as well as analytic querying. For the faster query processing, Brighthouse creates packages from the data rows. While the query is resolving, it decompresses only those packages that partially satisfy the condition of the query to avoid accessing all the database. However, Brighthouse used a constant parameter to create packages, this may create incompact packages and lead to large number of packages that are processed in each query. In this paper, at first, we define the task of partitioning data table into blocks as an optimization problem, then discuss the time complexity of the problem and propose an efficient algorithm, which creates dynamically data packages for efficient queries in databases. The experimental results shown the advantage of the proposed approach in package range reduction.\",\n \"Title: Efficient method for updating class association rules in dynamic datasets with record deletion.\\nYear: 2018\\n\\nAbstract: Association rule mining is an important topic in data mining. The problem is to discover all (or almost all) associations among items in the transaction database that satisfy some user-specified constraints. Usually, the constraints are related to minimal support and minimal confidence. Class association rules (CARs) are a special type of association rules that can be applied for classification problem. Previous research showed that classification based on association rules has higher accuracy than can be achieved with an inductive learning algorithm or C4.5. As such, many methods have been proposed for mining CARs, although these use batch processing. However, datasets are often changed, with records added or/and deleted, and consequently updating CARs is a challenging problem. This paper proposes an efficient method for updating CARs when records are deleted. First, we use an MECR-tree to store nodes for the original dataset. The information in the nodes of this tree are updated based on the deleted records. Second, the concept of pre-large itemsets is used to avoid rescanning the original dataset. Finally, we propose an algorithm to efficiently update and generate CARs. We also analyze the time complexity to show the efficiency of our proposed algorithm. The experimental results show that the proposed method outperforms mining CARs from the dataset after record deletion.\",\n \"Title: Search Result Clustering Based on Query Context.\\nYear: 2015\\n\\nAbstract: This paper introduces a novel, interactive and exploratory, approach to information retrieval search engines based on clustering. Presented method allows users to change the clustering structure by applying a free-text clustering context query that is treated as a criterion for document-to-cluster allocation. Exploration mechanisms are delivered by redefining the interaction scenario in which the user can interact with data on the level of topic discovery or cluster labeling. In this paper, the presented idea is realized by a graph structure called the Query-Summarize Graph. This data structure is useful in the definition of the similarity measure between the snippets as well as in the snippet clustering algorithm. The experiments on real-world data are showing that the proposed solution has many interesting properties and can be an alternative approach to interactive information retrieval.\",\n \"Title: On the possibility of correct concept learning in description logics.\\nYear: 2018\\n\\nAbstract: It is well known that any Boolean function in classical propositional calculus can be learned correctly if the training information system is good enough. In this paper, we extend that result for description logics. We prove that any concept in any description logic that extends \\\\(\\\\mathcal {ALC}\\\\) with some features amongst I (inverse roles), \\\\(Q_k\\\\) (qualified number restrictions with numbers bounded by a constant k), and \\\\(\\\\mathsf {Self}\\\\) (local reflexivity of a role) can be learned correctly if the training information system (specified as a finite interpretation) is good enough. That is, there exists a learning algorithm such that, for every concept C of those logics, there exists a training information system such that applying the learning algorithm to it results in a concept equivalent to C. For this result, we introduce universal interpretations and bounded bisimulation in description logics and develop an appropriate learning algorithm. We also generalize common types of queries for description logics, introduce interpretation queries, and present some consequences.\",\n \"Title: Tolerance Rough Set Model and Its Applications in Web Intelligence\\nYear: 2013\\n\\nAbstract: Tolerance Rough Set Model (TRSM) has been introduced as a tool for approximation of hidden concepts in text databases. In recent years, numerous successful applications of TRSM in web intelligence including text classification, clustering, thesaurus generation, semantic indexing, and semantic search, etc., have been proposed. This paper will review the fundamental concepts of TRSM, some of its possible extensions and some typical applications of TRSM in text mining. Moreover, the architecture o a semantic information retrieval system, called SONCA, will be presented to demonstrate the main idea as well as stimulate the further research on TRSM.\",\n \"Title: Towards VNUMED for Healthcare Research Activities in Vietnam.\\nYear: 2019\\n\\nAbstract: Inspired by MIMIC- III [1], VNUMED is a unified intermediate database of electronic medical records that is being developed in Vietnam. Its purpose is to gather medical records from hospitals, which can be used to support medical research.\",\n \"Title: Rotation Variance in Graph Convolutional Networks\\nYear: 2021\\n\\nAbstract: Convolution filters in deep convolutional networks display rotation variant behavior. While learned invariant behavior can be partially achieved, this paper shows that current methods of utilizing rotation variant features can be improved by proposing a grid-based graph convolutional network. By performing spectral graph convolutions on features extracted from subareas of images, we are able to ta...\",\n \"Title: Cellular Automata in Covid-19 prediction\\nYear: 2021\\n\\nAbstract: At the end of 2019 a new coronavirus emerged, turning into a world pandemic. The new coronavirus is called COVID-19. Different countries handled the pandemic differently and our main focus in this article is on Poland. For better counteracting and managing the situation a model for predicting the dynamics of the pandemic is needed. In this article we present a model for simulating future infections taking into account various preventive measures and locations in Poland. We based the model on a two-dimensional cellular automata, with spatial dependencies between regions, different population and size of simulated regions. (C) 2021 The Authors. Published by Elsevier B.V.\",\n \"Title: A Method for Closed Frequent Subgraph Mining in a Single Large Graph\\nYear: 2021\\n\\nAbstract: Mining frequent subgraphs is an interesting and important problem in the graph mining field, in that mining frequent subgraphs from a single large graph has been strongly developed, and has recently attracted many researchers. Among them, MNI-based approaches are considered as state-of-the-art, such as the GraMi algorithm. Besides frequent subgraph mining (FSM), frequent closed frequent subgraph mining was also developed. This has many practical applications and is a fundamental premise for many studies. This paper proposes the CloGraMi (Closed Frequent Subgraph Mining) algorithm based on GraMi to find all closed frequent subgraphs in a single large graph. Two effective strategies are also developed, the first one is a new level order traversal strategy to quickly determine closed subgraphs in the searching process, and the second is setting a condition for early pruning a large portion of non-closed candidates, both of them aim to reduce the running time as well as the memory requirements, improve the performance of the proposed algorithm. Our experiments are performed on five real datasets (both directed and undirected graphs) and the results show that the running time as well as the memory requirements of our algorithm are significantly better than those of the GraMi-based algorithm.\",\n \"Title: Feature Selection and Ranking Method based on Intuitionistic Fuzzy Matrix and Rough Sets\\nYear: 2022\\n\\nAbstract: In this paper we propose a novel rough-fuzzy hybridization technique to feature selection and feature ranking problem. The idea is to model the local preference relation between pair of features by intuitionistic fuzzy values and search for a feature ranking that is consistent with those constraints. We apply the techniques used in group decision making where constraints are presented in form of intuitionistic fuzzy preference relation. The proposed method has been illustrated by some simple examples and verified on a benchmark dataset.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":73,"string":"73"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13356,"string":"13,356"}}},{"rowIdx":13357,"cells":{"question_id":{"kind":"string","value":"Marcus Foth"},"question":{"kind":"string","value":"Generate an abstract for the title \"Fixing the city one photo at a time: mobile logging of maintenance requests\" using the following items: Mobile application, geo-tagged photos, maintenance request, user feedback, civic engagement."},"answer":{"kind":"string","value":"We have designed a mobile application that takes advantage of the built-in features of smart phones such as camera and GPS that allow users to take geo-tagged photos while on the move. Urban residents can take pictures of broken street furniture and public property requiring repair, attach a brief description, and submit the information as a maintenance request to the local government organisation of their city. This paper discusses the design approach that led to the application, highlights a built-in mechanism to elicit user feedback, and evaluates the progress to date with user feedback and log statistics. It concludes with an outlook highlighting user requested features and our own design aspirations for moving from a reporting tool to a civic engagement tool."},"correct_answer":{"kind":"string","value":"We have designed a mobile application that takes advantage of the built-in features of smart phones such as camera and GPS that allow users to take geo-tagged photos while on the move. Urban residents can take pictures of broken street furniture and public property requiring repair, attach a brief description, and submit the information as a maintenance request to the local government organisation of their city. This paper discusses the design approach that led to the application, highlights a built-in mechanism to elicit user feedback, and evaluates the progress to date with user feedback and log statistics. It concludes with an outlook highlighting user requested features and our own design aspirations for moving from a reporting tool to a civic engagement tool."},"documents":{"kind":"list like","value":["Title: Discussions in space\nYear: 2009\n\nAbstract: In-place digital augmentation enhances the experience of physical spaces through digital technologies that are directly accessible within that space. This can take place in many forms and ways, e.g., through location-aware applications running on the individuals' portable devices, such as smart phones, or through large static devices, such as public displays, which are located within the augmented space and accessible by everyone. The hypothesis of this study is that in-place digital augmentation, in the context of civic participation, where citizens collaboratively aim at making their community or city a better place, offers significant new benefits, because it allows access to services or information that are currently inaccessible to urban dwellers where and when they are needed: in place. This paper describes our work in progress deploying a public screen to promote civic issues in public, urban spaces, and to encourage public feedback and discourse via mobile phones.","Title: Fear and danger in nocturnal urban environments\nYear: 2010\n\nAbstract: At the centre of this research is an ethnographic study that saw the researcher embedded within the fabric of inner city life to better understand what characteristics of user activity and interaction could be enhanced by technology. The initial research indicated that the experience of traversing the city after dark unified an otherwise divergent user group through a shared concern for personal safety. Managing this fear and danger represented an important user need. We found that mobile social networking systems are not only integral for bringing people together, they can help in the process of users safely dispersing as well. We conclude, however, that at a time when the average iPhone staggers under the weight of a plethora of apps that do everything from acting as a carpenter's level to a pregnancy predictor, we consider the potential for the functionality of a personal safety device to be embodied within a stand alone artifact.","Title: Pervasive Technology and Public Transport: Opportunities Beyond Telematics\nYear: 2013\n\nAbstract: This review of IT-based services offered in public transportation focuses on the passenger's perspective. The authors suggest new directions for future services, stressing the need to develop frameworks for assessing service quality and customer satisfaction.","Title: A customisable dashboard display for environmental performance visualisations\nYear: 2013\n\nAbstract: We conducted an exploratory study of a mobile energy monitoring tool: The Dashboard. Our point of departure from prior work was the emphasis of end-user customisation and social sharing. Applying extensive feedback, we deployed the Dashboard in real-world conditions to socially linked research participants for a period of five weeks. Participants were encouraged to devise, construct, place, and view various data feeds . The aim of our study was to test the assumption that participants, having control over their Dashboard configuration, would engage, and remain engaged, with their energy feedback throughout the trial. Our research points to a set of design issues surrounding the adoption and continued use of such tools. A novel finding of our study is the impact of social links between participants and their continued engagement with the Dashboard. Our results also illustrate the emergence of energy-voyeurism, a form of social energy monitoring by peers.","Title: Digital soapboxes: towards an interaction design agenda for situated civic innovation\nYear: 2013\n\nAbstract: We argue that there are at least two significant issues for interaction designers to consider when creating the next generation of human interfaces for civic and urban engagement: (1) The disconnect between citizens participating in either digital or physical realms has resulted in a neglect of the hybrid role that public place and situated technology can play in contributing to civic innovation. (2) Under the veneer of many social media tools, hardly any meaningful strategies or approaches are found that go beyond awareness raising and allow citizens to do more than clicking a \"Like\" button. We call for an agenda to design the next generation of \"digital soapboxes\" that contributes towards a new form of polity helping citizens not only to have a voice but also to appropriate their city in order to take action for change.","Title: An Urban Informatics Approach To Smart City Learning In Architecture And Urban Design Education\nYear: 2013\n\nAbstract: This study aims to redefine spaces of learning to places of learning through the direct engagement of local communities as a way to examine and learn from real world issues in the city. This paper exemplifies Smart City Learning, where the key goal is to promote the generation and exchange of urban design ideas for the future development of South Bank, in Brisbane, Australia, informing the creation of new design policies responding to the needs of local citizens. Specific to this project was the implementation of urban informatics techniques and approaches to promote innovative engagement strategies. Architecture and Urban Design students were encouraged to review and appropriate real-time, ubiquitous technology, social media, and mobile devices that were used by urban residents to augment and mediate the physical and digital layers of urban infrastructures. Our study's experience found that urban informatics provide an innovative opportunity to enrich students' place of learning within the city.","Title: The sound of music: sharing song selections between collocated strangers in public urban places\nYear: 2012\n\nAbstract: This paper presents Capital Music, a mobile application enabling real-time sharing of song choices with collocated urban dwellers. Due to the real-time, location-based peer-to-peer approach of the application, a user experience study was performed utilising the Wizard of Oz method. The study provides insight into how sharing non-privacy sensitive but personal data in an anonymous way can influence the user experience of people in public urban places. We discuss the findings in relation to how Capital Music influences the process of \"cocooning\" in public urban places, the practice of designing anonymous interactions between collocated strangers, and how the sharing of song choices can create a sense of commonality between anonymous users in the urban space. The outcomes of this study are relevant for future location-based social networking applications that aim to create interactions between collocated strangers.","Title: Unleashing creative writers: situated engagement with mobile narratives\nYear: 2009\n\nAbstract: The emergence of sophisticated multimedia phones in combination with improvements to the mobile Internet provides the possibility to read texts and stories on mobile handsets. However, the question is, how to adapt stories in order to take advantage of the user's mobility and create an engaging and appealing experience. To address these new conditions, a Mobile Narrative was created and access to individual chapters of the story was restricted. Authors can specify constraints, such as a location or time, which need to be met by the reader if they want to read the story. This concept allows creative writers of the story to exploit the fact that the reader's context is known, by intensifying the user experience and integrating this knowledge into the writing process. Interviews with authors and creative writers and two user studies explored the effects of this way of writing on both parties. The paper presents our preliminary research findings discussing this new experience that was found to be exciting and interesting by both sides.","Title: Social and mobile interaction design to increase the loyalty rates of young blood donors\nYear: 2013\n\nAbstract: Young adults represent the largest group of first time donors to the Australian Red Cross Blood Service, but they are also the least loyal group and often do not return after their first donation. At the same time, many young people use the internet and various forms of social media on a daily basis. Web and mobile based technological practices and communication patterns change the way that young people interact with one another, with their families, and communities. Combining these two points of departure, this study seeks to identify best practices of employing mobile apps and social media in order to enhance the loyalty rates of young blood donors. The findings reported in this paper are based on a qualitative approach presenting a nuanced understanding of the different factors that motivate young people to donate blood in the first place, as well as the obstacles or issues that prevent them from returning. The paper discusses work in progress with a view to inform the development of interactive prototypes trialling three categories of features: personal services (such as scheduling); social media (such as sharing the donation experience with friends to raise awareness); and data visualisations (such as local blood inventory levels). We discuss our translation of research findings into design implications.","Title: EatChaFood: challenging technology design to slice food waste production\nYear: 2013\n\nAbstract: This paper presents work in progress of EatChaFood -- a prototype app designed to increase user knowledge of the currently available domestic supply and location of food, with a view to reducing expired household food waste. In order to reap the benefits that EatChaFood can provide we explore ways to overcome manual data entry as a barrier to use. Our user study has to recognise the limitations of the prototype app, and conduct an evaluation of the interaction design built into the app to promote behaviour change. Innovations in the near future such as the automatic scanning of barcodes on food items or photo-recognition will close the gap between perceived prototype usability and usefulness.","Title: CityFlocks: designing social navigation for urban mobile information systems\nYear: 2008\n\nAbstract: CityFlocks is a mobile system enabling visitors and new residents in a city to tap into the knowledge and experiences of local residents, so as to gather information about their new environment. Its design specifically aims to lower existing barriers of access and facilitate social navigation in urban places. This paper presents a design case study of a mobile system prototype that offers an easy way for information seeking new residents or visitors to access tacit knowledge from local people about their new community. In various user tests we evaluate two general user interaction alternatives - direct and indirect social navigation - and analyse under what conditions which interaction method works better for people using a mobile device to socially navigate urban environments. The outcomes are relevant for the user interaction design of future mobile information systems that leverage off of a social navigation approach.","Title: Content sharing on public screens: experiences through iterating social and spatial contexts\nYear: 2012\n\nAbstract: This paper describes the design and study of public urban screen applications aiming to facilitate urban dwellers to control content shown on public urban screens. Two types of content sharing are presented: aggregating existing social media content about particular locations for sharing, and sharing online videos with collocated people at a public urban screen. The paper describes an exploratory study, an observational study, as well as an interpretational study in regards to application usage and user experience. Sharing content on public urban screens can pique the curiosity of users towards collocated people and the application itself resulting in raised awareness of collocated people.","Title: Welcome to the jungle: HCI after dark\nYear: 2011\n\nAbstract: The transformation of urban spaces that occurs once darkness falls is simultaneously exhilarating and menacing, and over the past 20 months we have investigated the potential for mobile technology to help users manage their personal safety concerns in the city at night. Our findings subverted commonly held notions of vulnerability, with the threat of violence felt equally by men and women. But while women felt protected because of their mobile technology, men dismissed it as digital Man Mace. We addressed this macho design challenge by studying remote engineers in outback Australia to inspire our personal safety design prototype MATE.","Title: Designing participation in agile ridesharing with mobile social software\nYear: 2009\n\nAbstract: Growing participation is a key challenge for the viability of sustainability initiatives, many of which require enactment at a local community level in order to be effective. This paper undertakes a review of technology assisted carpooling in order to understand the challenge of designing participation and consider how mobile social software and interface design can be brought to bear. It was found that while persuasive technology and social networking approaches have roles to play, critical factors in the design of carpooling are convenience, ease of use and fit with contingent circumstances, all of which require a use-centred approach to designing a technological system and building participation. Moreover, the reach of technology platform-based global approaches may be limited if they do not cater to local needs. An approach that focuses on iteratively designing technology to support and grow mobile social ridesharing networks in particular locales is proposed. The paper contributes an understanding of HCI approaches in the context of other designing participation approaches.","Title: Enhancing the experience of public transport users with urban screens and mobile applications\nYear: 2010\n\nAbstract: Public transportation is an environment with great potential for applying location-based services through mobile devices. This paper provides the underpinning rationale for research that will be looking at how the real-time passenger information system deployed by the Translink Transit Authority across all of South East Queensland in Australia can provide a core platform to improve commuters' user experiences. This system relies on mobile computing and GPS technology to provide accurate information on transport vehicle locations. The proposal builds on this platform to inform the design and development of innovative social media, mobile computing and geospatial information applications. The core aim is to digitally augment the public transport environment to enhance the user experience of commuters for a more enjoyable journey.","Title: Motivating domestic energy conservation through comparative, community-based feedback in mobile and social media\nYear: 2011\n\nAbstract: The progress of technology has led to the increased adoption of energy monitors among household energy consumers. While the monitors available on the market deliver real-time energy usage feedback to the consumer, the format of this data is usually unengaging and mundane. Moreover, it fails to address consumers with different motivations and needs to save and compare energy. This paper presents a study that seeks to provide initial indications for motivation-specific design of energy-related feedback. We focus on comparative feedback supported by a community of energy consumers. In particular, we examine eco-visualisations, temporal self-comparison, norm comparison, one-on-one comparison and ranking, whereby the last three allow us to explore the potential of socialising energy-related feedback. These feedback types were integrated in EnergyWiz -- a mobile application that enables users to compare with their past performance, neighbours, contacts from social networking sites and other EnergyWiz users. The application was evaluated in personal, semi-structured interviews, which provided first insights on how to design motivation-related comparative feedback.","Title: Libraries as coworking spaces: Understanding user motivations and perceived barriers to social learning.\nYear: 2013\n\nAbstract: Purpose - This paper aims to inform design strategies for smart space technology to enhance libraries as environments for coworking and informal social learning. The focus is on understanding user motivations, behaviour, and activities in the library when there is no programmed agenda. Design/methodology/approach - The study analyses gathered data over five months of ethnographic research at The Edge a \"bookless\" library space at the State Library of Queensland in Brisbane, Australia, that is explicitly dedicated to coworking, social learning, peer collaboration, and creativity around digital culture and technology. Findings - The results present five personas that embody people's main usage patterns as well as motivations, attitudes, and perceived barriers to social learning. It appears that most users work individually or within pre-organised groups, but usually do not make new connections with co-present, unacquainted users. Based on the personas, four hybrid design dimensions are suggested to improve the library as a social interface for shared learning encounters across physical and digital spaces. Originality/value - The findings in this paper offer actionable knowledge for managers, decision makers, and designers of technology-enhanced library spaces and similar collaboration and coworking spaces.","Title: Capital music: personal expression with a public display of song choice\nYear: 2010\n\nAbstract: Using information and communication technology devices in public urban places can help to create a personalised space. Looking at a mobile phone screen or listening to music on an MP3 player is a common practice avoiding direct contact with others e.g. whilst using public transport. However, such devices can also be utilised to explore how to build new meaningful connections with the urban space and the collocated people within. We present findings of work-in-progress on Capital Music, a mobile application enabling urban dwellers to listen to music songs as usual, but also allowing them to announce song titles and discover songs currently being listened to by other people in the vicinity. We study the ways that this tool can change or even enhance people's experience of public urban spaces. Our first user study also found changes in choosing different songs. Anonymous social interactions based on users' music selection are implemented in the first iteration of the prototype that we studied.","Title: Engaging energy saving through motivation-specific social comparison\nYear: 2011\n\nAbstract: Comparison is widely used in research projects and commercial products whose goal is to motivate energy saving at home. This research builds on fundamental theories from social psychology in an attempt to shed light on how to motivate consumers to conserve energy by providing relevant people for social comparison depending on consumer's motivation to compare. To support the research process, the mobile application EnergyWiz was developed through a theory-driven design approach. Along with other features EnergyWiz provides users with three types of social comparison - normative, one-on-one and ranking. The results of interviews with prospective users are used to derive design suggestions for relevant people for comparison (comparison subjects).","Title: Facilitating Social Networking in Inner-City Neighborhoods\nYear: 2006\n\nAbstract: The success of new social networking systems for residents of inner-city neighborhoods depends on the software's ability to animate and support meaningful interaction between proximate users, to network serendipitous social encounters, and to seamlessly integrate with the way interaction takes place in existing urban social networks.","Title: Location-Aware Computing, Virtual Networks\nYear: 2009\n\nAbstract: This issue includes four works in process on issues and applications in location-aware computing: letting users set and control privacy policies when they use location-aware applications, cold-starting recommender systems for mobile location-aware services, aggregating contextual information for location-based applications, and applying location-based services to public transportation environments. The department also includes a report on lightweight virtualization of low-power wireless personal area networks.","Title: The Second Life of urban planning? Using NeoGeography tools for community engagement\nYear: 2009\n\nAbstract: The majority of the world's citizens now live in cities. Although urban planning can thus be thought of as a field with significant ramifications on the human condition, many practitioners feel that it has reached the crossroads in thought leadership between traditional practice and a new, more participatory and open approach. Conventional ways to engage people in participatory planning exercises are limited in reach and scope. At the same time, socio-cultural trends and technology innovation offer opportunities to re-think the status quo in urban planning. NeoGeography introduces tools and services that allow non-geographers to use advanced geographical information systems. Similarly, is there a potential for the emergence of a neo-planning paradigm in which urban planning is carried out through active civic engagement aided by Web 2.0 and new media technologies thus redefining the role of practicing planners? This paper traces a number of evolving links between urban planning, NeoGeography and information and communication technology. Two significant trends-participation and visualisation-with direct implications for urban planning are discussed. Combining advanced participation and visualisation features, the popular virtual reality environment Second Life is then introduced as a test bed to explore a planning workshop and an integrated software event framework to assist narrative generation. We discuss an approach to harness and analyse narratives using virtual reality logging to make transparent how users understand and interpret proposed urban designs.","Title: Design considerations for community portals in master-planned developments in Australia and Mexico\nYear: 2008\n\nAbstract: This paper presents a discussion of design considerations for community web portals as social networking systems. We analyse and compare the social interaction approach, design considerations and socio-technical requirements with regards to community portal technology employed in two master-planned urban developments in Australia and Mexico. We focus on how the human and social concepts and local contextualisations affect technology design and use. In response to our analysis, and to face the challenge of designing for variability and diversity, we present the communicative ecology model as a conceptual tool to help researchers and designers grasp the situated context and purpose of these systems in order to inform the design and development of better community technology.","Title: More than wires, pipes and ducts: some lessons from grassroots networked communities and master-planned neighbourhoods\nYear: 2006\n\nAbstract: Community informatics research has found that the provision of technical connectivity in local neighbourhoods alone does not ensure community interaction Externally initiated projects applied to communities by government or commercial bodies have encountered difficulties where the project's goals do not correspond to the host community's Differing expectations can lead to disillusionment or rejection Self-organised initiatives developed from within communities appear to be more aligned with residents' goals and purposes and may not face these issues However, such initiatives have also encountered difficulties in maintaining volunteer input and achieving technological sustainability Valuable insights can be drawn from both cases In this paper we review examples of each type of initiative and consider lessons that can be taken forward into new networked neighbourhood initiatives currently being developed We consider one specific example, an inner-city master-planned residential development in Australia seeking to establish a community association to support socio-economic sustainability and governance of the local ICT infrastructure We offer recommendations drawn from existing projects that may be applied to this site and to a wider context, and consider some implications for the future selection, deployment and maintenance of community information systems.","Title: Please take out your phones: on the spot solicitation of student feedback in class\nYear: 2012\n\nAbstract: The use of mobile devices such as smart phones and tablets in classrooms has been met with mixed sentiments. Some instructors and teachers see them as a distraction and regularly ban their usage. Others who see their potential to enhance learning have started to explore ways to integrate them into their teaching in an attempt to improve student engagement. In this paper we report on a pilot study that forms part of a university-wide project reconceptualising its approach to the student evaluation of learning and teaching. In a progressive decision to embrace mobile technology, the university decided to trial a smart phone app designed for students to check-in to class and leave feedback on the spot. Our preliminary findings from trialling the app indicate that the application establishes a more immediate feedback loop between students and teachers. However, the app's impact depends on how feedback is shared with students and how the teaching team responds.","Title: Gelatine: making coworking places gel for better collaboration and social learning\nYear: 2013\n\nAbstract: Public libraries and coworking spaces seek for means to facilitate peer collaboration, peer inspiration and cross-pollination of skills and creativity. However, social learning, inspiration and collaboration between coworkers do not come naturally. In particular in (semi-) public spaces, the behavioural norm among unacquainted coworkers is to work in individual silos without taking advantage of social learning or collaboration opportunities. This paper presents results from a pilot study of 'Gelatine' -- a system that facilitates shared encounters between coworkers by allowing them to digitally 'check in' at a work space. Gelatine displays skills, areas of interest, and needs of currently present coworkers on a public screen. The results indicate that the system amplifies users' sense of place and awareness of other coworkers, and serves as an interface for social learning through exploratory, opportunistic and serendipitous inspirations, as well as through helping users identify like-minded peers for follow-up face-to-face encounters. We discuss how Gelatine is perceived by users with different pre-entry motivations, and discuss users' challenges as well as non-use of the system.","Title: Designing for place-based social interaction of urban residents in México, South Africa and Australia\nYear: 2006\n\nAbstract: The design of technology to facilitate social interaction of urban residents is increasingly important for many countries around the world. México and South Africa are particularly prone to issues that stem from urban densification and a lack of adequate affordable housing. Governments look to ICT to take on a mediating and facilitating role. This paper reports on research-inprogress of a tri-continental study. The external factors and aims of this pilot project identifying local case studies to prepare for a larger and longer term international comparison of local community networking approaches are examined. It is argued that by careful attention to cultural and social assets in the community, innovations will be engendered which enhance economic and social development. Preliminary design implications for the support of neighbourhood interactions across different socio-cultural contexts are presented.","Title: Colour coding the fridge to reduce food waste\nYear: 2012\n\nAbstract: This paper introduces the first iteration of a study aimed at grouping similar food types together in a refrigerator to increase the awareness of available foods for consumers in a domestic environment. The goals of the project are twofold: i) Raise the awareness of available foods for all members of a household; ii) Reduce the amount of expired food waste in the household. The project implemented a paper-based colour scheme in refrigerators in households, assigning colours to particular food types (e.g. green to fruit and vegetables, red to meat, etc.). The findings show that the colour coding raised participants' awareness of available food items in the fridge, particularly for those participants who were not directly involved in the shopping and initial storage of each food item. The findings also indicate that such awareness led to a reduction in expiration of food and thus general food waste in the household. These preliminary findings suggest that raising awareness of food availability through categorisation and efficient communication of this information may lead to a reduction in food waste in domestic environments.","Title: Analyzing The Factors Influencing The Successful Design And Uptake Of Interactive Systems To Support Social Networks In Urban Neighborhoods\nYear: 2006\n\nAbstract: In urban residential environments in Australia and other developed countries, Internet access is on the verge of becoming a ubiquitous utility like gas or electricity. From an urban sociology and community informatics perspective, this article discusses new emerging social formations of urban residents that are based on networked individualism and the potential of Internet-based systems to support them. It proposes that one of the main reasons for the disappearance or nonexistence of urban residential communities is a lack of appropriate opportunities and instruments to encourage and support local interaction in urban neighborhoods. The article challenges the view that a mere reappropriation of applications used to support dispersed virtual communities is adequate to meet the place and proximity-based design requirements that community networks in urban neighborhoods pose. It argues that the key factors influencing the successful design and uptake of interactive systems to support social networks in urban neighborhoods include the swarming social behavior of urban dwellers; the dynamics of their existing communicative ecology; and the serendipitous, voluntary, and place-based quality of interaction between residents on the basis of choice, like-mindedness, mutual interest and support needs. Drawing on an analysis of these factors, the conceptual design framework of a prototype system - the urban tribe incubator - is presented.","Title: HCI for City Farms: Design Challenges and Opportunities.\nYear: 2013\n\nAbstract: Urban agriculture plays an important role in many facets of food security, health and sustainability. The city farm is one such manifestation of urban agriculture: it functions as a location centric social hub that supplies food, education, and opportunities for strengthening the diverse sociocultural fabrics of the local community. This paper presents the case of Northey Street City Farm in Brisbane, Australia as an opportunity space for design. The paper identifies four areas that present key challenges and opportunities for HCI design that support social sustainability of the city farm: A preference for face-to-face contact leads to inconsistencies in shared knowledge; a dependence on volunteers and very limited resources necessitates easily accessible interventions; other local urban agricultural activity needing greater visibility; and the vulnerability of the physical location to natural phenomenon, in this instance flooding, present a design challenge and a need to consider disaster management.","Title: Virtual fish: visual evidence of connectivity in a master-planned urban community\nYear: 2007\n\nAbstract: The rapid densification of urban areas around the world offers exciting opportunities for new place-based artworks and locative media that aim at engaging, informing and entertaining members of local communities. In this paper, we introduce a design competition for concepts of interaction design which display visual evidence of connectivity in a master-planned community. This competition is based in and focuses on one of Brisbane's newly built inner urban renewal developments. Furthermore, we introduce the conceptual interaction design of one of the competition's winning entries, as well as its potential and its challenges to engage local residents in participation and exploration of place-based information and community media.","Title: TrainRoulette: promoting situated in-train social interaction between passengers\nYear: 2013\n\nAbstract: Travelling by public transport is usually regarded as boring and uninteresting. Refraining from talking to the stranger next to you may be due to limitations that are self-imposed and further corroborated by social expectations and cultural norms that govern behaviour in public space. Our design research into passenger interactions on board of urban commuter trains has informed the development of the TrainRoulette prototype -- a mobile app for situated, real-time chats between train passengers. We study the impact of our design intervention on shaping perceptions of the train journey experience. Moreover, we are interested in the implications of such ICT-mediated interactions within train journeys for stimulating social offline interactions and new forms of passenger engagement.","Title: Towards visualising people's ecology of hybrid personal learning environments\nYear: 2012\n\nAbstract: Ambient media architecture can provide place-based collaborative learning experiences and pathways for social interactions that would not be otherwise possible. This paper is concerned with ways of enhancing peer-to-peer learning affordances in library spaces; how can the library facilitate the community of library users to learn from each other? We report on the findings of a study that employed a participatory design method where participants were asked to reflect and draw places, social networks, and activities that they use to work (be creative, productive), play (have fun, socialize, be entertained), and learn (acquire new information, knowledge, or skills). The results illustrate how informal learning -- learning outside the formal education system -- is facilitated by a personal selection of physical and socio-cultural environments, as well as online tools, platforms, and networks. This paper sheds light on participants' individually curated ecologies of their work, play, and learning related networks and the hybrid (physical and digital) nature of these places. These insights reveal opportunities for ambient media architecture to increase awareness of and connections between people's hybrid personal learning environments.","Title: People, content, location: sweet spotting urban screens for situated engagement\nYear: 2012\n\nAbstract: A growing body of research is looking at ways to bring the processes and benefits of online deliberation to the places they are about and in turn allow a larger, targeted proportion of the urban public to have a voice, be heard, and engage in questions of city planning and design. Seeking to take advantage of the civic opportunities of situated engagement through public screens and mobile devices, our research informed a public urban screen content application DIS that we deployed and evaluated in a wide range of real world public and urban environments. For example, it is currently running on the renowned urban screen at Federation Square in Melbourne. We analysed the data from these user studies within a conceptual framework that positions situated engagement across three key parameters: people, content, and location. We propose a way to identify the sweet spot within the nexus of these parameters to help deploy and run interactive systems to maximise the quality of the situated engagement for civic and related deliberation purposes.","Title: Suburban nostalgia: the community building potential of urban screens\nYear: 2008\n\nAbstract: Urbanely nomadic residents are increasingly forgoing the potential of locale based serendipitous encounters in favour of digitally mediated interactions within their walled garden of existing social networks. This limits a sense of community in urban neighbourhoods to members of one's social network, but what of interactions with those outside of these networks, such as inhabitants of residential spaces? We report on our pilot study of open ended interviews which investigates the different user archetypes whose needs we consider when designing social technology for urban spaces. We propose a design to extend the sense of community in urban neighbourhoods beyond pure network sociality. Through a lens of 'suburban nostalgia' we envision how neighbourhood interactions might be retrofitted in new ways through civic engagement in the enhancement of environments.","Title: The social car: new interactive vehicular applications derived from social media and urban informatics\nYear: 2012\n\nAbstract: Digital information that is place- and time-specific, is increasingly becoming available on all aspects of the urban landscape. People (cf. the Social Web), places (cf. the Geo Web), and physical objects (cf. ubiquitous computing, the Internet of Things) are increasingly infused with sensors, actuators, and tagged with a wealth of digital information. Urban informatics research explores these emerging digital layers of the city at the intersection of people, place and technology. However, little is known about the challenges and new opportunities that these digital layers may offer to road users driving through today's mega cities. We argue that this aspect is worth exploring in particular with regards to Auto-UI's overarching goal of making cars both safer and more enjoyable. This paper presents the findings of a pilot study, which included 14 urban informatics research experts participating in a guided ideation (idea creation) workshop within a simulated environment. They were immersed into different driving scenarios to imagine novel urban informatics type of applications specific to the driving context.","Title: Collective and network sociality in an urban village\nYear: 2008\n\nAbstract: Our ongoing research program explores the communicative ecology of urban residents and the way these findings can inform design innovation of interactive web, mobile and geospatial applications and local communication services. This paper presents results of a study within this program that seeks to develop a better understanding of the way residents choose different types of web and mobile technology to oscillate between collective and networked interaction paradigms. The analysis of this data draws out key distinctions between collective and network sociality in place-based settings. It points in the direction of design opportunities for global web services to be translated and appropriated for local use to support everyday connections, place making efforts and participatory urbanism and citizenship.","Title: Learning beyond books—strategies for ambient media to improve libraries and collaboration spaces as interfaces for social learning\nYear: 2014\n\nAbstract: With the advent of digital media and online information resources, public libraries as physical destinations for information access are being increasingly challenged. As a response, many libraries follow the trend of removing bookshelves in order to provide more floorspace for social interaction and collaboration. Such spaces follow a Commons 2.0 model: they are designed to support collaborative work and social learning. The acquisition of skills and knowledge is facilitated as a result of being surrounded by and interacting with a community of likeminded others. Based on the results of a case study on a Commons 2.0 library space, this paper describes several issues of collaboration and social learning in public library settings. Acknowledging the significance of the architectural characteristics of the physical space, we discuss opportunities for ambient media to better reflect the social attributes of the library as a place; i.e. amplify the sense of other co-present library visitors and provide opportunities for shared encounters and conversations, which would remain invisible otherwise. We present the design of a user check-in system for improving the library as a physical destination for social learning, sharing, and inspiration for and by the community.","Title: Participatory Data Analytics: Collaborative Interfaces for Data Composition and Visualisation\nYear: 2014\n\nAbstract: This research proposes the development of interfaces to support collaborative, community-driven inquiry into data, which we refer to as Participatory Data Analytics. Since the investigation is led by local communities, it is not possible to anticipate which data will be relevant and what questions are going to be asked. Therefore, users have to be able to construct and tailor visualisations to their own needs. The poster presents early work towards defining a suitable compositional model, which will allow users to mix, match, and manipulate data sets to obtain visual representations with little-to-no programming knowledge. Following a user-centred design process, we are subsequently planning to identify appropriate interaction techniques and metaphors for generating such visual specifications on wall-sized, multi-touch displays.","Title: Technicolouring the fridge: reducing food waste through uses of colour-coding and cameras\nYear: 2014\n\nAbstract: Domestic food wastage is a growing problem for the environment and food security. Some causes of domestic food wastes are attributed to a consumer's behaviours during food purchasing, storage and consumption, such as: excessive food purchases and stockpiling in storage. Recent efforts in human-computer interaction research have examined ways of influencing consumer behaviour. The outcomes have led to a number of interventions that assist users with performing everyday tasks. The Internet Fridge is an example of such an intervention. However, new pioneering technologies frequently confront barriers that restrict their future impact in the market place, which has prompted investigations into the effectiveness of behaviour changing interventions used to encourage more sustainable practices. In this paper, we investigate and compare the effectiveness of two interventions that encourage behaviour change: FridgeCam and the Colour Code Project. We use FridgeCam to examine how improving a consumer's food supply knowledge can reduce food stockpiling. We use the Colour Code Project to examine how improving consumer awareness of food location can encourage consumption of forgotten foods. We explore opportunities to integrate these interventions into commercially available technologies, such as the Internet Fridge, to: (i) increase the technology's benefit and value to users, and (ii) promote reduced domestic food wastage. We conclude that interventions improving consumer food supply and location knowledge can promote behaviours that reduce domestic food waste over a longer term. The implications of this research present new opportunities for existing and future technologies to play a key role in reducing domestic food waste.","Title: Vote With Your Feet: Local Community Polling on Urban Screens\nYear: 2014\n\nAbstract: Falling prices have led to an ongoing spread of public displays in urban areas. Still, they mostly show passive content such as commercials and digital signage. At the same time, technological advances have enabled the creation of interactive displays potentially increasing their attractiveness for the audience, e.g. through providing a platform for civic discourse. This poses considerable challenges, since displays need to communicate the opportunity to engage, motivate the audience to do so, and be easy to use. In this paper we present Vote With Your Feet, a hyperlocal public polling tool for urban screens allowing users to express their opinions. Similar to vox populi interviews on TV or polls on news websites, the tool is meant to reflect the mindset of the community on topics such as current affairs, cultural identity and local matters. It is novel in that it focuses on a situated civic discourse and provides a tangible user interface, tackling the mentioned challenges. It shows one Yes/No question at a time and enables users to vote by stepping on one of two tangible buttons on the ground. This user interface was introduced to attract people's attention and to lower participation barriers. Our field study showed that Vote With Your Feet is perceived as inviting and that it can spark discussions among co-located people.","Title: UbiOpticon: Participatory Sousveillance with Urban Screens and Mobile Phone Cameras\nYear: 2014\n\nAbstract: In many cities around the world, surveillance by a pervasive net of CCTV cameras is a common phenomenon in an attempt to uphold safety and security across the urban environment. Video footage is being recorded and stored, sometimes live feeds are being watched in control rooms hidden from public access and view. In this study, we were inspired by Steve Mann's original work on sousveillance (surveillance from below) to examine how a network of camera equipped urban screens could allow the residents of Oulu in Finland to collaborate on the safekeeping of their city. An agile, rapid prototyping process led to the design, implementation and 'in the wild' deployment of the UbiOpticon screen application. Live video streams captured by web cams integrated at the top of 12 distributed urban screens were broadcast and displayed in a matrix arrangement on all screens. The matrix also included live video streams of two roaming mobile phone cameras. In our field study we explored the reactions of passers-by and users of this screen application that seeks to inverse Bentham's original panopticon by allowing the watched to be watchers at the same time. In addition to the original goal of participatory sousveillance, the system's live video feature sparked fun and novel user-led apprlopriations.","Title: DIY media architecture: open and participatory approaches to community engagement\nYear: 2014\n\nAbstract: Media architecture's combination of the digital and the physical can trigger, enhance, and amplify urban experiences. In this paper, we examine how to bring about and foster more open and participatory approaches to engage communities through media architecture by identifying novel ways to put some of the creative process into the hands of laypeople. We review technical, spatial, and social aspects of DIY phenomena with a view to better understand maker cultures, communities, and practices. We synthesise our findings and ask if and how media architects as a community of practice can encourage the 'open-sourcing' of information and tools allowing laypeople to not only participate but become active instigators of change in their own right. We argue that enabling true DIY practices in media architecture may increase citizen control. Seeking design strategies that foster DIY approaches, we propose five areas for further work and investigation. The paper begs many questions indicating ample room for further research into DIY Media Architecture.","Title: Pervasive Computing and Environmental Sustainability: Two Conference Workshops\nYear: 2009\n\nAbstract: Raising people's awareness with environmental data and educational information does not necessarily trigger sufficient motivation to change their habits towards a more environmentally friendly and sustainable lifestyle. This article reports on two workshops at Pervasive 2008 and UbiComp 2008 that sought to develop a better understanding how to go beyond just informing and into motivating and encouraging action and change. Drawing on participatory culture, ubiquitous computing, and real-time information, participants discussed research and development of viable new design approaches and information interfaces that can strengthen our position to meet the targets of the Kyoto protocol, and contribute to the sustainability of a low-carbon future.","Title: Darkness and Disaster in the City\nYear: 2011\n\nAbstract: People all over the world are regularly hit by floods, cyclones, and other natural disasters. Many use smart phones and social media to stay connected, seek help, improvise, and cope with crises or challenging situations. This column discusses these practices after dark or during disasters to unveil challenges and opportunities for innovative designs that increase resilience and safety.","Title: Digital cities 9 workshop - hackable cities: from subversive city making to systemic change\nYear: 2015\n\nAbstract: The DC9 workshop takes place on June 27, 2015 in Limerick, Ireland and is titled \\\"Hackable Cities: From Subversive City Making to Systemic Change\\\". The notion of \\\"hacking\\\" originates from the world of media technologies but is increasingly often being used for creative ideals and practices of city making. \\\"City hacking\\\" evokes more participatory, inclusive, decentralized, playful and subversive alternatives to often top-down ICT implementations in smart city making. However, these discourses about \\\"hacking the city\\\" are used ambiguously and are loaded with various ideological presumptions, which makes the term also problematic. For some \\\"urban hacking\\\" is about empowering citizens to organize around communal issues and perform aesthetic urban interventions. For others it raises questions about governance: what kind of \\\"city hacks\\\" should be encouraged or not, and who decides? Can city hacking be curated? For yet others, trendy participatory buzzwords like these are masquerades for deeply libertarian neoliberal values. Furthermore, a question is how \\\"city hacking\\\" may mature from the tactical level of smart and often playful interventions to the strategic level of enduring impact. The Digital Cities 9 workshop welcomes papers that explore the idea of \\\"hackable city making\\\" in constructive and critical ways.","Title: Vote as you go: blending interfaces for community engagement into the urban space\nYear: 2015\n\nAbstract: This paper presents a series of studies on situated interfaces for community engagement. Firstly, we identify five recurring design challenges as well as four common strategies used to overcome them. We then assess the effectiveness of these strategies through field studies with public polling interfaces. We developed two very different polling interfaces in the form of (1) a web application running on an iPad mounted on a stand, allowing one vote at a time, and (2) a playful full-body interaction application for a large urban screen allowing concurrent participation. We deployed both interfaces in an urban precinct with high pedestrian traffic and equipped with a large urban screen. Analysing discoverability and learnability of each scenario, we derive insights regarding effective ways of blending community engagement interfaces into the built environment, while attracting the attention of passers-by and communicating the results of civic participation.","Title: Collaborative Data Exploration Interfaces - From Participatory Sensing to Participatory Sensemaking\nYear: 2015\n\nAbstract: As technological capabilities for capturing, aggregating, and processing large quantities of data continue to improve, the question becomes how to effectively utilise these resources. Whenever automatic methods fail, it is necessary to rely on human background knowledge, intuition, and deliberation. This creates demand for data exploration interfaces that support the analytical process, allowing users to absorb and derive knowledge from data. Such interfaces have historically been designed for experts. However, existing research has shown promise in involving a broader range of users that act as citizen scientists, placing high demands in terms of usability. Visualisation is one of the most effective analytical tools for humans to process abstract information. Our research focuses on the development of interfaces to support collaborative, community-led inquiry into data, which we refer to as Participatory Data Analytics. The development of data exploration interfaces to support independent investigations by local communities around topics of their interest presents a unique set of challenges, which we discuss in this paper. We present our preliminary work towards suitable high-level abstractions and interaction concepts to allow users to construct and tailor visualisations to their own needs.","Title: Ad hoc communities on the road: Serendipitous social encounters to enhance tourist experiences\nYear: 2015\n\nAbstract: Driving can be a lonely activity. While there has been a lot of research and technical inventions concerning car-to-car communication and passenger entertainment, there is still little work concerning connecting drivers. Whereas tourism is very much a social activity, drive tourists and road trippers have few options to communicate with fellow travelers. Our study is placed at the intersection of tourism and driving. It aims to enhance the trip experience during driving through social interaction. This paper explores how a mobile application that allows instant messaging between travelers sharing similar context can establish a temporary, ad hoc community and enhance the road trip experience. A prototype was developed and evaluated in various user and field studies. The study's outcomes are relevant for the design of future mobile tourist guides that benefit from community design, social encounters and recommendations.","Title: TrainYarn: Probing perceptions of social space in urban commuter trains\nYear: 2015\n\nAbstract: We studied the ways that urban commuter train passengers experience their journeys. We present the design process and in-situ evaluation of TrainYarn, a mobile app prototype designed to facilitate social interaction between co-located urban train passengers. Through the deployment of the prototype, we sought to probe perceptions of social space with a view to positively impact the assessment of public transport. Our results support that our target users saw value in the use of TrainYarn, perceiving it as emancipatory, in alignment with their communicative needs, and having the ability to transform their perceptions of social space. To further inform future research and practice, we put forward a series of design recommendations.","Title: From users to citizens: Some thoughts on designing for polity and civics\nYear: 2015\n\nAbstract: This paper presents an essay aimed at prompting broad discussion crucial in keeping the interaction design discourse fresh, critical, and in motion. We trace the changing role of people who have advanced from consumers to producers, from stationary office workers to mobile urban nomads, from passive members of the plebs to active instigators of change. Yet, interaction designers often still refer to them only as 'users.' We follow some of the historic developments from the information superhighway to the smart city in order to provide the backdrop in front of which we critically analyse three core areas. First, the issue of echo chambers and filter bubbles in social media results in a political polarisation that jeopardises the formation of a functioning public sphere. Second, pretty lights and colourful façades in media architecture are increasingly making way for situated installations and interventions fostering community engagement. And third, civic activism is often reduced to forms of slacktivism. We synthesise our discussion to propose 'citizen-ability' as an alternative goal for interaction designers to aspire to in order to create new polities and civics for a better quality of life.","Title: Urban Informatics beyond Data: Media Architecture, Placemaking, and Citizen Action\nYear: 2015\n\nAbstract: Since 2006, we have been conducting urban informatics research that we define as \\\"the study, design, and practice of urban experiences across different urban contexts that are created by new opportunities of real-time, ubiquitous technology and the augmentation that mediates the physical and digital layers of people networks and urban infrastructures\\\" [1]. Various new research initiatives under the label \\\"urban informatics\\\" have been started since then by universities (e.g., NYU's Center for Urban Science and Progress) and industry (e.g., Arup, McKinsey) worldwide. Yet, many of these new initiatives are limited to what Townsend calls, \\\"data-driven approaches to urban improvement\\\" [2]. One of the key challenges is that any quantity of aggregated data does not easily translate directly into quality insights to better understand cities. In this talk, I will raise questions about the purpose of urban informatics research beyond data, and show examples of media architecture, participatory city making, and citizen activism. I argue for (1) broadening the disciplinary foundations that urban science approaches draw on; (2) maintaining a hybrid perspective that considers both the bird's eye view as well as the citizen's view, and; (3) employing design research to not be limited to just understanding, but to bring about actionable knowledge that will drive change for good.","Title: Citizens breaking out of filter bubbles: urban screens as civic media.\nYear: 2016\n\nAbstract: Social media platforms risk polarising public opinions by employing proprietary algorithms that produce filter bubbles and echo chambers. As a result, the ability of citizens and communities to engage in robust debate in the public sphere is diminished. In response, this paper highlights the capacity of urban interfaces, such as pervasive displays, to counteract this trend by exposing citizens to the socio-cultural diversity of the city. Engagement with different ideas, networks and communities is crucial to both innovation and the functioning of democracy. We discuss examples of urban interfaces designed to play a key role in fostering this engagement. Based on an analysis of works empirically-grounded in field observations and design research, we call for a theoretical framework that positions pervasive displays and other urban interfaces as civic media. We argue that when designed for more than wayfinding, advertisement or television broadcasts, urban screens as civic media can rectify some of the pitfalls of social media by allowing the polarised user to break out of their filter bubble and embrace the cultural diversity and richness of the city.","Title: Social Living Labs for Digital Participation: Designing with Regional and Rural Communities.\nYear: 2016\n\nAbstract: \\\"Fostering digital participation through Living Labs in regional and rural Australian communities,\\\" is a three year research project funded by the Australian Research Council. The project aims to identify the specific digital needs and practices of regional and rural residents in the context of the implementation of high speed internet. It seeks to identify new ways for enabling residents to develop their digital confidence and skills both at home and in the community. This two-day symposium will bring together researchers and practitioners from diverse backgrounds to discuss design practices in social living labs that aim to foster digital inclusion and participation. Day one will consist of practitioner and research reports, while day two will provide an opportunity for participants to imagine and design future digital participation strategies. Academic participants will also have an opportunity to contribute to a refereed edited volume by Chandos Publishing (an imprint of Elsevier).","Title: The role of passenger-centric innovation in the future of public transport.\nYear: 2016\n\nAbstract: Although hard factors such as availability, efficiency, safety, and comfort make up the core of the public transport quality of service, they are only a part of the bigger picture. This bigger picture is modified and shaped daily, where the increasing permeation of technology creates new possibilities for passengers to experience their journeys. Despite technology becoming ubiquitous in public transport, it has had only limited impact on how passengers connect affectively and symbolically with the service. This “affective gap” is at the core of what differentiates private and public transport. Being able to reduce this gap is therefore valuable to passengers and public transport service providers alike. In this paper, we build on existing and ongoing work to discuss the relevance of a passenger-centric approach to innovation in the field of public transport. This passenger-centric approach puts passengers at the centre of future solutions, where their evolving needs, desires, and values are used to guide how to enhance the existing core functionality of the service. To test our hypothesis that passenger-centric innovation is valuable to passengers and advantageous to service providers alike, we put forward a review on how innovation is being approached in both the aviation and car industries. This review is supported by our own insights, which have been based on data collected from urban rail commuters in Australia. We further support our argument by looking at particular examples of innovation in the field of public transport, and discussing the existing barriers and drivers that can, respectively, hinder or propel passenger-centric innovation.","Title: Glance: generalized geometric primitives and transformations for information visualization in AR/VR environments.\nYear: 2016\n\nAbstract: This paper outlines Glance, a unifying framework for exploring multidimensional, multivariate data in the context of AR/VR environments, along with specific implementation techniques that utilize programmable GPUs. The presented techniques extend the graphics pipeline through programmable shaders in order to support more general geometries and operations. Our point of departure from existing structural theories of graphics is a general spatial substrate, where data is encoded using higher-dimensional geometric primitives. From there, we define a series of processing stages, utilizing shaders to enable flexible and dynamic coordinate transformations. Furthermore, we describe how advanced visualization techniques, such as faceting and multiple views, can be integrated elegantly into our model. Bridging between Computer Graphics and Information Visualization theories, the elements of our framework are composable and expressive, allowing a diverse set of visualizations to be specified in a universal manner (see figure 1).","Title: Grids and networks: two exploratory approaches for visualising bibliometric data on very large displays.\nYear: 2016\n\nAbstract: Current personal single-user devices, such as smartphones, tablets, or laptops, struggle to provide the contextual awareness and coordination capabilities required for the effective collaborative analysis of large datasets. Instead, large interactive displays offer unique opportunities for co-located collaboration in meeting room environments. However, supporting collaborative interaction across multiple large displays presents distinctive challenges for interaction designers. This paper explores and compares novel interaction techniques and visualisations for large displays, with a focus on two distinct approaches for collaborative browsing and filtering of multivariate datasets: (i) shared zoomable grid view, and (ii) multiple individual network views. In order to evaluate the effectiveness of our proposed interfaces for multi-user exploratory analysis, we applied the designs to a specific use case, namely the problem of displaying research metadata from bibliographic databases to extract and collate narratives and overarching themes for research grant proposals. Following an agile design methodology, we created two prototypes incorporating our designs. We weigh the benefits and limitations of each approach by comparing them along two key dimensions: (i) methods of interaction, and (ii) visual representation. Subsequently, we compare the two design approaches and discuss the circumstances and situations that would be beneficial for use. This research and its implications are intended to inform future research exploring the design of collaborative interfaces for large-scale interaction environments.","Title: Exploring tangible interaction for map-based feedback.\nYear: 2016\n\nAbstract: This paper describes the development of a series of tangible feedback mechanisms for an analogue map-based feedback interface. By prototyping interactions with simple everyday analogue materials, the goal was to explore playful, tangible input methods for our interface, beyond a more conventional screen-based approach that could inform future development of a digital map-based feedback interface. Four different prototype interactions were developed that could work in a completely analogue implementation. These interactions were installed and evaluated as part of an in-the-wild deployment of a larger project, which was used as part of a community consultation process. By analysing how people used our interaction prototypes and the feedback that they left, data was collected to inform later iterations with the kinds of interaction approaches that can successfully engage participants and the most effective methods of soliciting feedback.","Title: CrowdRisk: exploring crowdsourcing of risk information.\nYear: 2016\n\nAbstract: This paper describes the outcomes of a preliminary study into the design of a mobile app to crowdsource information related to \\\"risk\\\". For the purpose of this study the notion of risk is defined broadly; however, we predominantly focus on the personal, subjective perception of risk. The study involved building a prototypical mobile app to crowdsource risk and exploring the use of the app as part of an expert workshop. Outcomes show challenges and opportunities with regards to the categorisation of results, the motivation of users, and interaction design of the prototype. The study provides value by giving an initial insight into this design space.","Title: Designing Gamified Applications that Make Safe Driving More Engaging.\nYear: 2017\n\nAbstract: Low levels of engagement while driving can pose road safety risks, e.g., inattention during low traffic or routine trips. Interactive technologies that increase task engagement could therefore offer safety benefits, e.g., through performance feedback, increased challenge, and incentives. As a means to build upon these notions, we chose to explore gamification of the driving task. The research aim was to study how to design gamified applications that make safe driving more engaging. We present six design lenses which bring into focus considerations most relevant to creating engaging car applications. A user study enhanced our understanding of design requirements and revealed user personas to support the development of such applications. These lenses and personas informed two prototypes, which we evaluated in driving simulator studies. Our results indicate that the gamified conditions increased driver engagement and reduced driving speeds. As such, our work contributes towards the design of engaging applications that are both appropriate to the safety-critical driving context and compelling to users.","Title: The promise of blockchain technology for interaction design.\nYear: 2017\n\nAbstract: After its first prominent application as part of the digital currency Bitcoin, blockchain technology is gaining in popularity. It comprises a chain of blocks (the ledger) that provides a secure, immutable and auditable list of ordered records. Using both cryptography and a distributed database, once a block is recorded, it can no longer be changed. In Bitcoinu0027s case, the ledger contains the history of all currency transactions. This paper offers a critical overview of the blockchain technology for an interaction design audience, in three parts: (1) The principles making block-chain technology possible are briefly explained using examples. (2) Specific cases such as food provenance and supply chain tracing, are used to illustrate both the wide array of possible applications and the profound implications of blockchain technology. (3) Opportunities and challenges for HCI and interaction design are discussed in the form of a nascent research agenda.","Title: The work of making: reflections on the process, form and function of two sets of design research artefacts.\nYear: 2017\n\nAbstract: In this paper we present a reflexive account of the development of two separate Research-through-Design studies. We draw from the experience of designing and creating two separate sets of design research artefacts that fit within a broader study into everyday domestic life. The paperu0027s contribution is structured around three elements relating to the development of design research artefacts and the: 1) Participants; 2) Researchers; 3) Study. It further aims to emphasise the need for a range of documentation on the diverse approaches researchers take within their design processes.","Title: Rat running the G20: collective intelligence for navigating the disrupted city.\nYear: 2018\n\nAbstract: Large-scale political or cultural events in urban environments disrupt and challenge city residents in making informed decisions to navigate through restricted zones. However, little research exists that examines how residents successfully overcome the mobility turmoils created by such events. Studies into collective intelligence found socio-technical efforts that can assist citizens in dealing with challenging situations in urban environments. Yet, studies into other forms of collective and network sociality and how those forms are interwoven with the social construction of urban space, are rare. In this paper, we present data from the 2014 G20 Summit held in Brisbane, Australia, to propose that collective-informed decisions made by urban residents in disrupted environments are influenced by particular communication patterns and information access, as well as the production and reproduction of urban imaginaries. An urban exploration as the G20 event unfolded, followed by audio-recorded focus groups, was conducted with 14 participants who mapped their walks through the city using a mobile app and captured images of different locations along their paths. The analysis of these data contributes towards a deeper understanding of collective intelligence strategies for citizens interacting with urban space and gives rise to potential strategies for enhancing socio-spatial engagement of urban residents.","Title: Creativity and design to articulate difference in the conflicted city: collective intelligence in Bogota's grassroots organisations.\nYear: 2018\n\nAbstract: This paper presents a critical reflection on insights into the ongoing endeavours for community engagement by Ayara and MAL; two urban grassroot organisations in Bogota, Colombia, where a long history of internal conflicts has resulted in diverse human right violations. The paper presents examples of the grassroots organisations’ unique methods of engagement that promotes building collective intelligence from the bottom–up through creative collaboration and design processes, leading to rebuilding social fabrics that support the common good for the people of Bogota.","Title: DoGood: examining gamification, civic engagement, and collective intelligence.\nYear: 2018\n\nAbstract: The mobile internet provides new and easier ways for people to organise themselves, raise issues, take action, and interact with their city. However, lack of information or motivation often prevents citizens from regularly contributing to the common good. In this paper, we present DoGood, a mobile app that aims at motivating citizens to join civic activities in their local community. Our study asks to what extent gamification can motivate users to participate in civic activities. The term civic activity is not yet well defined, so we collect activities citizens consider to be civic to work towards a broadly accepted definition of the term. The DoGood app uses gamified elements that we studied to gauge their role in encouraging citizens to submit and promote their civic activities as well as to join the activities of others. DoGood was implemented and deployed to citizens in a five-week-long user study. The app succeeded in motivating most of its users to do more civic activities, and its gamified elements were well received.","Title: On Scale, Dialectics, And Affect: Pathways For Proliferating Participatory Design\nYear: 2018\n\nAbstract: The Participatory Design (PD) community is committed to continuously refine its technological, social, political, and scientific agenda, and as a result, PD has become more widely adopted, robust, and sophisticated. Yet, PD's advancement cannot end here. The gap between those who can contribute to the shaping of future technologies and those who are reduced to consumers, has - if anything - widened on a grand scale. In response, we argue through three lenses: scale, dialectics, and affect in PD, and suggest some pathways to build bridges, foster alliances, and evolve PD practice to proliferate the democratisation in technology design that has been a strong value driving PD. Scale asks about ways for PD to extend its reach without giving up on its core qualities. Dialectics is about creating and maintaining the spaces and fora for constructive conflict by networking and linking with other stakeholders, organisations, and domains. Finally, affect discusses how PD can put forward democratic visions of technological futures that connect to people's hearts, acknowledging that decisions are often made irrationally and unconsciously. Our review draws attention to opportunities for PD to travel between different contexts and proliferate through interconnected and intermediary knowledge and an embodied literacy that enables PD to reach further into industry, government, and community.","Title: More-than-human urban futures: speculative participatory design to avoid ecocidal smart cities.\nYear: 2018\n\nAbstract: We propose a collective participatory speculative urban walk exploring more-than-human perspectives for smart cities. The walk will be a curated selection of outcomes from a PDC workshop interrogating how more-than-human approaches and their resultant ethical, legal, and methodological concerns can shape participatory design practices toward cohabitation. Our aim with the Situated Action is to use the walk as an embodied approach to push forward a cultural change in the agenda of sustainable smart cities, urban informatics and IoT. The walk will draw from the specificity of urban infrastructures in Hasselt associated with more-than-human approaches and include a selection of provisional artefacts in the form of low-fi prototypes, manifestos or future scenarios from the workshop to scaffold participation within the urban environment for conference delegates and citizens.","Title: Avoiding ecocidal smart cities: participatory design for more-than-human futures.\nYear: 2018\n\nAbstract: The turn to participation in smart cities was intended to increase the involvement of diverse, often marginalised, citizens in the design and use of networked sensing technologies. However, ideals of activism, citizen engagement and democratisation through the co-design of networked technologies and services have been largely based on an understanding of urban space as separate from nature, and for human inhabitants alone. In current conditions of climate change, pollution, and loss of biodiversity, a human-centred perspective of cities is increasingly problematic. This workshop focuses on an expanded more-than-human perspective for cities, informed by studies in the Anthropocene in fields such as STS, geography, planning and design. We will interrogate how more-than-human perspectives and their resultant ethical, legal, and methodological concerns can shape participatory design practices and policies towards cohabitation, and push forward a cultural change in the agenda of sustainable smart cities, urban informatics, IoT, and design.","Title: More-than-Human Media Architecture\nYear: 2018\n\nAbstract: We consider some of the planetary conditions and global circumstances that both research and practice of media architecture are embedded within, such as climate change, pollution, resource consumption, and loss of biodiversity. While there has been a notable increase in emphasis on participation and engagement in design and use, with the aim to increase the involvement of diverse and often marginalised citizens, a human-centred approach to media architecture comes with its own set of problems. In this paper, we want to draw the attention of the media architecture community to the fallacy of human exceptionalism and anthropocentrism. We present a critical review of examples of media architecture projects and installations that question our understanding of urban space as separate from nature, and designed primarily for humans and just humans. Informed by studies in disciplines such as science and technology studies, critical geography, urban planning, and interaction design, we use insights derived from our review to discuss ways towards a more-than-human approach to media architecture. We conclude by proposing for discussion nascent design considerations for media architecture to go beyond the needs of just humans and to consider new ways to appreciate and cater for our broader ecological entanglements with plants, animals, and the environment at large.","Title: More-than-human participation: design for sustainable smart city futures.\nYear: 2019\n\nAbstract: In this forum we highlight innovative thought, design, and research in the area of interaction design and sustainability, illustrating the diversity of approaches across HCI communities. --- Roy Bendor, Editor","Title: The Premise of Institutioning for the Proliferation of Communities and Technologies Research\nYear: 2019\n\nAbstract: The role of institutions both as stakeholders in the work that communities and technologies (C&T;) researchers are engaged in and as facilitators for ensuring continuity and scale-making of outcomes, impact and community benefits, is starting to be revisited. This paper connects the debate in the C&T; community about its relevance and ongoing remit, with debates in the participatory design field about the role of the triad of infrastructuring, commoning, and more recently institutioning. In doing so, it considers the premise of institutioning for the proliferation of C&T; research. After a review of institutionalism and its foundational application to these discussions, the paper offers a conceptual framework that illustrates both the triad's interrelatedness and the need for orienting future C&T; efforts away from depoliticisation and towards a more active pursuit of targeting meso- and macro-levels of community institutions, political framing, and planetary impact.","Title: From premise to practice of social consensus: How to agree on common knowledge in blockchain-enabled supply chains\nYear: 2021\n\nAbstract: Attaining \"Common Knowledge\" is essential in the formation of deals and agreements, but is hard to achieve over point-to-point communication networks such as the Internet. While blockchain technologies provide a helpful mechanism in the form of technical consensus, originally created to resolve the double-spending problem, little does it address impediments to proper contract formation that have to do with the quality of exogenous data, asymmetry of information, or even its suitability (the colloquial garbage-in/garbage-out problem). In the face of the limitations of technical consensus, we explore how the strengths of technical consensus can be utilized by introducing another dimension of consensus - what we have called social consensus - which directly addresses the formation of true (if retrospective) Common Knowledge essential to arms-length agreement between multiple actors. We have eschewed the notion that social consensus as an epistemological concern, and instead focus on mechanisms by which environments of multiple actors form and sustain bodies of information that enable them to go about their activities with a reasonable level of confidence that others in the supply chain will 'do their bit,' backed by a 'failsafe' mechanism enforced by cryptography which holds the actors unharmed in case the envisioned finality is not obtained. These bodies of information create what is essentially a retrospective form of common knowledge, and a lesser variant, mutual knowledge. We propose an implementation from the preferred mechanism of a multisig primitive, which builds and improves on the Gnosis multisig, in the use case of decentralized blockchain-powered supply chains consisting of multiple parties, human and machine.","Title: Garbage in garbage out: The precarious link between IoT and blockchain in food supply chains\nYear: 2022\n\nAbstract: •Presents a theoretical argument based on a study of Australia-China beef exports.•Critiques data quality and validity assumptions in many IoT and blockchain systems.•Changes oracle identity and data validity practices using ‘common knowledge’ notion.•Limits possible capricious claims on IoT data performance in blockchain systems.•Proposes mechanism design for data to become lead indicators of desired future states.","Title: Non-human Personas: Including Nature in the Participatory Design of Smart Cities\nYear: 2021\n\nAbstract: For the past decades humans have been placed at the centre of designing information and communication technologies (ICT), leading to the rise in prominence of human-centred design. The field of smart cities has equally adopted notions of citizen participation as a way to ensure that technological solutions improve people's livelihoods. However, these kinds of processes treat the urban environment as separate from nature, promoting human comfort and convenience over planetary health and wellbeing. Motivated by these growing concerns that highlight the urgency to reconsider how we define and practice participation in smart cities and in human-centred ICT solutions more broadly, this article assesses how the personas method can be adapted to include more-than-human perspectives in the design process. Based on a case study, which involved designing smart urban furniture for human and non-human use, we introduce a framework for developing and employing non-human personas. As a key element of the framework, we describe a middle-out approach for forming a coalition that can speak on behalf of the non-human species that are impacted by design decisions. We demonstrate how the framework can be used through its retrospective application on two research-led smart city projects. The article concludes with a discussion of key principles for creating and using non-human personas in design projects."],"string":"[\n \"Title: Discussions in space\\nYear: 2009\\n\\nAbstract: In-place digital augmentation enhances the experience of physical spaces through digital technologies that are directly accessible within that space. This can take place in many forms and ways, e.g., through location-aware applications running on the individuals' portable devices, such as smart phones, or through large static devices, such as public displays, which are located within the augmented space and accessible by everyone. The hypothesis of this study is that in-place digital augmentation, in the context of civic participation, where citizens collaboratively aim at making their community or city a better place, offers significant new benefits, because it allows access to services or information that are currently inaccessible to urban dwellers where and when they are needed: in place. This paper describes our work in progress deploying a public screen to promote civic issues in public, urban spaces, and to encourage public feedback and discourse via mobile phones.\",\n \"Title: Fear and danger in nocturnal urban environments\\nYear: 2010\\n\\nAbstract: At the centre of this research is an ethnographic study that saw the researcher embedded within the fabric of inner city life to better understand what characteristics of user activity and interaction could be enhanced by technology. The initial research indicated that the experience of traversing the city after dark unified an otherwise divergent user group through a shared concern for personal safety. Managing this fear and danger represented an important user need. We found that mobile social networking systems are not only integral for bringing people together, they can help in the process of users safely dispersing as well. We conclude, however, that at a time when the average iPhone staggers under the weight of a plethora of apps that do everything from acting as a carpenter's level to a pregnancy predictor, we consider the potential for the functionality of a personal safety device to be embodied within a stand alone artifact.\",\n \"Title: Pervasive Technology and Public Transport: Opportunities Beyond Telematics\\nYear: 2013\\n\\nAbstract: This review of IT-based services offered in public transportation focuses on the passenger's perspective. The authors suggest new directions for future services, stressing the need to develop frameworks for assessing service quality and customer satisfaction.\",\n \"Title: A customisable dashboard display for environmental performance visualisations\\nYear: 2013\\n\\nAbstract: We conducted an exploratory study of a mobile energy monitoring tool: The Dashboard. Our point of departure from prior work was the emphasis of end-user customisation and social sharing. Applying extensive feedback, we deployed the Dashboard in real-world conditions to socially linked research participants for a period of five weeks. Participants were encouraged to devise, construct, place, and view various data feeds . The aim of our study was to test the assumption that participants, having control over their Dashboard configuration, would engage, and remain engaged, with their energy feedback throughout the trial. Our research points to a set of design issues surrounding the adoption and continued use of such tools. A novel finding of our study is the impact of social links between participants and their continued engagement with the Dashboard. Our results also illustrate the emergence of energy-voyeurism, a form of social energy monitoring by peers.\",\n \"Title: Digital soapboxes: towards an interaction design agenda for situated civic innovation\\nYear: 2013\\n\\nAbstract: We argue that there are at least two significant issues for interaction designers to consider when creating the next generation of human interfaces for civic and urban engagement: (1) The disconnect between citizens participating in either digital or physical realms has resulted in a neglect of the hybrid role that public place and situated technology can play in contributing to civic innovation. (2) Under the veneer of many social media tools, hardly any meaningful strategies or approaches are found that go beyond awareness raising and allow citizens to do more than clicking a \\\"Like\\\" button. We call for an agenda to design the next generation of \\\"digital soapboxes\\\" that contributes towards a new form of polity helping citizens not only to have a voice but also to appropriate their city in order to take action for change.\",\n \"Title: An Urban Informatics Approach To Smart City Learning In Architecture And Urban Design Education\\nYear: 2013\\n\\nAbstract: This study aims to redefine spaces of learning to places of learning through the direct engagement of local communities as a way to examine and learn from real world issues in the city. This paper exemplifies Smart City Learning, where the key goal is to promote the generation and exchange of urban design ideas for the future development of South Bank, in Brisbane, Australia, informing the creation of new design policies responding to the needs of local citizens. Specific to this project was the implementation of urban informatics techniques and approaches to promote innovative engagement strategies. Architecture and Urban Design students were encouraged to review and appropriate real-time, ubiquitous technology, social media, and mobile devices that were used by urban residents to augment and mediate the physical and digital layers of urban infrastructures. Our study's experience found that urban informatics provide an innovative opportunity to enrich students' place of learning within the city.\",\n \"Title: The sound of music: sharing song selections between collocated strangers in public urban places\\nYear: 2012\\n\\nAbstract: This paper presents Capital Music, a mobile application enabling real-time sharing of song choices with collocated urban dwellers. Due to the real-time, location-based peer-to-peer approach of the application, a user experience study was performed utilising the Wizard of Oz method. The study provides insight into how sharing non-privacy sensitive but personal data in an anonymous way can influence the user experience of people in public urban places. We discuss the findings in relation to how Capital Music influences the process of \\\"cocooning\\\" in public urban places, the practice of designing anonymous interactions between collocated strangers, and how the sharing of song choices can create a sense of commonality between anonymous users in the urban space. The outcomes of this study are relevant for future location-based social networking applications that aim to create interactions between collocated strangers.\",\n \"Title: Unleashing creative writers: situated engagement with mobile narratives\\nYear: 2009\\n\\nAbstract: The emergence of sophisticated multimedia phones in combination with improvements to the mobile Internet provides the possibility to read texts and stories on mobile handsets. However, the question is, how to adapt stories in order to take advantage of the user's mobility and create an engaging and appealing experience. To address these new conditions, a Mobile Narrative was created and access to individual chapters of the story was restricted. Authors can specify constraints, such as a location or time, which need to be met by the reader if they want to read the story. This concept allows creative writers of the story to exploit the fact that the reader's context is known, by intensifying the user experience and integrating this knowledge into the writing process. Interviews with authors and creative writers and two user studies explored the effects of this way of writing on both parties. The paper presents our preliminary research findings discussing this new experience that was found to be exciting and interesting by both sides.\",\n \"Title: Social and mobile interaction design to increase the loyalty rates of young blood donors\\nYear: 2013\\n\\nAbstract: Young adults represent the largest group of first time donors to the Australian Red Cross Blood Service, but they are also the least loyal group and often do not return after their first donation. At the same time, many young people use the internet and various forms of social media on a daily basis. Web and mobile based technological practices and communication patterns change the way that young people interact with one another, with their families, and communities. Combining these two points of departure, this study seeks to identify best practices of employing mobile apps and social media in order to enhance the loyalty rates of young blood donors. The findings reported in this paper are based on a qualitative approach presenting a nuanced understanding of the different factors that motivate young people to donate blood in the first place, as well as the obstacles or issues that prevent them from returning. The paper discusses work in progress with a view to inform the development of interactive prototypes trialling three categories of features: personal services (such as scheduling); social media (such as sharing the donation experience with friends to raise awareness); and data visualisations (such as local blood inventory levels). We discuss our translation of research findings into design implications.\",\n \"Title: EatChaFood: challenging technology design to slice food waste production\\nYear: 2013\\n\\nAbstract: This paper presents work in progress of EatChaFood -- a prototype app designed to increase user knowledge of the currently available domestic supply and location of food, with a view to reducing expired household food waste. In order to reap the benefits that EatChaFood can provide we explore ways to overcome manual data entry as a barrier to use. Our user study has to recognise the limitations of the prototype app, and conduct an evaluation of the interaction design built into the app to promote behaviour change. Innovations in the near future such as the automatic scanning of barcodes on food items or photo-recognition will close the gap between perceived prototype usability and usefulness.\",\n \"Title: CityFlocks: designing social navigation for urban mobile information systems\\nYear: 2008\\n\\nAbstract: CityFlocks is a mobile system enabling visitors and new residents in a city to tap into the knowledge and experiences of local residents, so as to gather information about their new environment. Its design specifically aims to lower existing barriers of access and facilitate social navigation in urban places. This paper presents a design case study of a mobile system prototype that offers an easy way for information seeking new residents or visitors to access tacit knowledge from local people about their new community. In various user tests we evaluate two general user interaction alternatives - direct and indirect social navigation - and analyse under what conditions which interaction method works better for people using a mobile device to socially navigate urban environments. The outcomes are relevant for the user interaction design of future mobile information systems that leverage off of a social navigation approach.\",\n \"Title: Content sharing on public screens: experiences through iterating social and spatial contexts\\nYear: 2012\\n\\nAbstract: This paper describes the design and study of public urban screen applications aiming to facilitate urban dwellers to control content shown on public urban screens. Two types of content sharing are presented: aggregating existing social media content about particular locations for sharing, and sharing online videos with collocated people at a public urban screen. The paper describes an exploratory study, an observational study, as well as an interpretational study in regards to application usage and user experience. Sharing content on public urban screens can pique the curiosity of users towards collocated people and the application itself resulting in raised awareness of collocated people.\",\n \"Title: Welcome to the jungle: HCI after dark\\nYear: 2011\\n\\nAbstract: The transformation of urban spaces that occurs once darkness falls is simultaneously exhilarating and menacing, and over the past 20 months we have investigated the potential for mobile technology to help users manage their personal safety concerns in the city at night. Our findings subverted commonly held notions of vulnerability, with the threat of violence felt equally by men and women. But while women felt protected because of their mobile technology, men dismissed it as digital Man Mace. We addressed this macho design challenge by studying remote engineers in outback Australia to inspire our personal safety design prototype MATE.\",\n \"Title: Designing participation in agile ridesharing with mobile social software\\nYear: 2009\\n\\nAbstract: Growing participation is a key challenge for the viability of sustainability initiatives, many of which require enactment at a local community level in order to be effective. This paper undertakes a review of technology assisted carpooling in order to understand the challenge of designing participation and consider how mobile social software and interface design can be brought to bear. It was found that while persuasive technology and social networking approaches have roles to play, critical factors in the design of carpooling are convenience, ease of use and fit with contingent circumstances, all of which require a use-centred approach to designing a technological system and building participation. Moreover, the reach of technology platform-based global approaches may be limited if they do not cater to local needs. An approach that focuses on iteratively designing technology to support and grow mobile social ridesharing networks in particular locales is proposed. The paper contributes an understanding of HCI approaches in the context of other designing participation approaches.\",\n \"Title: Enhancing the experience of public transport users with urban screens and mobile applications\\nYear: 2010\\n\\nAbstract: Public transportation is an environment with great potential for applying location-based services through mobile devices. This paper provides the underpinning rationale for research that will be looking at how the real-time passenger information system deployed by the Translink Transit Authority across all of South East Queensland in Australia can provide a core platform to improve commuters' user experiences. This system relies on mobile computing and GPS technology to provide accurate information on transport vehicle locations. The proposal builds on this platform to inform the design and development of innovative social media, mobile computing and geospatial information applications. The core aim is to digitally augment the public transport environment to enhance the user experience of commuters for a more enjoyable journey.\",\n \"Title: Motivating domestic energy conservation through comparative, community-based feedback in mobile and social media\\nYear: 2011\\n\\nAbstract: The progress of technology has led to the increased adoption of energy monitors among household energy consumers. While the monitors available on the market deliver real-time energy usage feedback to the consumer, the format of this data is usually unengaging and mundane. Moreover, it fails to address consumers with different motivations and needs to save and compare energy. This paper presents a study that seeks to provide initial indications for motivation-specific design of energy-related feedback. We focus on comparative feedback supported by a community of energy consumers. In particular, we examine eco-visualisations, temporal self-comparison, norm comparison, one-on-one comparison and ranking, whereby the last three allow us to explore the potential of socialising energy-related feedback. These feedback types were integrated in EnergyWiz -- a mobile application that enables users to compare with their past performance, neighbours, contacts from social networking sites and other EnergyWiz users. The application was evaluated in personal, semi-structured interviews, which provided first insights on how to design motivation-related comparative feedback.\",\n \"Title: Libraries as coworking spaces: Understanding user motivations and perceived barriers to social learning.\\nYear: 2013\\n\\nAbstract: Purpose - This paper aims to inform design strategies for smart space technology to enhance libraries as environments for coworking and informal social learning. The focus is on understanding user motivations, behaviour, and activities in the library when there is no programmed agenda. Design/methodology/approach - The study analyses gathered data over five months of ethnographic research at The Edge a \\\"bookless\\\" library space at the State Library of Queensland in Brisbane, Australia, that is explicitly dedicated to coworking, social learning, peer collaboration, and creativity around digital culture and technology. Findings - The results present five personas that embody people's main usage patterns as well as motivations, attitudes, and perceived barriers to social learning. It appears that most users work individually or within pre-organised groups, but usually do not make new connections with co-present, unacquainted users. Based on the personas, four hybrid design dimensions are suggested to improve the library as a social interface for shared learning encounters across physical and digital spaces. Originality/value - The findings in this paper offer actionable knowledge for managers, decision makers, and designers of technology-enhanced library spaces and similar collaboration and coworking spaces.\",\n \"Title: Capital music: personal expression with a public display of song choice\\nYear: 2010\\n\\nAbstract: Using information and communication technology devices in public urban places can help to create a personalised space. Looking at a mobile phone screen or listening to music on an MP3 player is a common practice avoiding direct contact with others e.g. whilst using public transport. However, such devices can also be utilised to explore how to build new meaningful connections with the urban space and the collocated people within. We present findings of work-in-progress on Capital Music, a mobile application enabling urban dwellers to listen to music songs as usual, but also allowing them to announce song titles and discover songs currently being listened to by other people in the vicinity. We study the ways that this tool can change or even enhance people's experience of public urban spaces. Our first user study also found changes in choosing different songs. Anonymous social interactions based on users' music selection are implemented in the first iteration of the prototype that we studied.\",\n \"Title: Engaging energy saving through motivation-specific social comparison\\nYear: 2011\\n\\nAbstract: Comparison is widely used in research projects and commercial products whose goal is to motivate energy saving at home. This research builds on fundamental theories from social psychology in an attempt to shed light on how to motivate consumers to conserve energy by providing relevant people for social comparison depending on consumer's motivation to compare. To support the research process, the mobile application EnergyWiz was developed through a theory-driven design approach. Along with other features EnergyWiz provides users with three types of social comparison - normative, one-on-one and ranking. The results of interviews with prospective users are used to derive design suggestions for relevant people for comparison (comparison subjects).\",\n \"Title: Facilitating Social Networking in Inner-City Neighborhoods\\nYear: 2006\\n\\nAbstract: The success of new social networking systems for residents of inner-city neighborhoods depends on the software's ability to animate and support meaningful interaction between proximate users, to network serendipitous social encounters, and to seamlessly integrate with the way interaction takes place in existing urban social networks.\",\n \"Title: Location-Aware Computing, Virtual Networks\\nYear: 2009\\n\\nAbstract: This issue includes four works in process on issues and applications in location-aware computing: letting users set and control privacy policies when they use location-aware applications, cold-starting recommender systems for mobile location-aware services, aggregating contextual information for location-based applications, and applying location-based services to public transportation environments. The department also includes a report on lightweight virtualization of low-power wireless personal area networks.\",\n \"Title: The Second Life of urban planning? Using NeoGeography tools for community engagement\\nYear: 2009\\n\\nAbstract: The majority of the world's citizens now live in cities. Although urban planning can thus be thought of as a field with significant ramifications on the human condition, many practitioners feel that it has reached the crossroads in thought leadership between traditional practice and a new, more participatory and open approach. Conventional ways to engage people in participatory planning exercises are limited in reach and scope. At the same time, socio-cultural trends and technology innovation offer opportunities to re-think the status quo in urban planning. NeoGeography introduces tools and services that allow non-geographers to use advanced geographical information systems. Similarly, is there a potential for the emergence of a neo-planning paradigm in which urban planning is carried out through active civic engagement aided by Web 2.0 and new media technologies thus redefining the role of practicing planners? This paper traces a number of evolving links between urban planning, NeoGeography and information and communication technology. Two significant trends-participation and visualisation-with direct implications for urban planning are discussed. Combining advanced participation and visualisation features, the popular virtual reality environment Second Life is then introduced as a test bed to explore a planning workshop and an integrated software event framework to assist narrative generation. We discuss an approach to harness and analyse narratives using virtual reality logging to make transparent how users understand and interpret proposed urban designs.\",\n \"Title: Design considerations for community portals in master-planned developments in Australia and Mexico\\nYear: 2008\\n\\nAbstract: This paper presents a discussion of design considerations for community web portals as social networking systems. We analyse and compare the social interaction approach, design considerations and socio-technical requirements with regards to community portal technology employed in two master-planned urban developments in Australia and Mexico. We focus on how the human and social concepts and local contextualisations affect technology design and use. In response to our analysis, and to face the challenge of designing for variability and diversity, we present the communicative ecology model as a conceptual tool to help researchers and designers grasp the situated context and purpose of these systems in order to inform the design and development of better community technology.\",\n \"Title: More than wires, pipes and ducts: some lessons from grassroots networked communities and master-planned neighbourhoods\\nYear: 2006\\n\\nAbstract: Community informatics research has found that the provision of technical connectivity in local neighbourhoods alone does not ensure community interaction Externally initiated projects applied to communities by government or commercial bodies have encountered difficulties where the project's goals do not correspond to the host community's Differing expectations can lead to disillusionment or rejection Self-organised initiatives developed from within communities appear to be more aligned with residents' goals and purposes and may not face these issues However, such initiatives have also encountered difficulties in maintaining volunteer input and achieving technological sustainability Valuable insights can be drawn from both cases In this paper we review examples of each type of initiative and consider lessons that can be taken forward into new networked neighbourhood initiatives currently being developed We consider one specific example, an inner-city master-planned residential development in Australia seeking to establish a community association to support socio-economic sustainability and governance of the local ICT infrastructure We offer recommendations drawn from existing projects that may be applied to this site and to a wider context, and consider some implications for the future selection, deployment and maintenance of community information systems.\",\n \"Title: Please take out your phones: on the spot solicitation of student feedback in class\\nYear: 2012\\n\\nAbstract: The use of mobile devices such as smart phones and tablets in classrooms has been met with mixed sentiments. Some instructors and teachers see them as a distraction and regularly ban their usage. Others who see their potential to enhance learning have started to explore ways to integrate them into their teaching in an attempt to improve student engagement. In this paper we report on a pilot study that forms part of a university-wide project reconceptualising its approach to the student evaluation of learning and teaching. In a progressive decision to embrace mobile technology, the university decided to trial a smart phone app designed for students to check-in to class and leave feedback on the spot. Our preliminary findings from trialling the app indicate that the application establishes a more immediate feedback loop between students and teachers. However, the app's impact depends on how feedback is shared with students and how the teaching team responds.\",\n \"Title: Gelatine: making coworking places gel for better collaboration and social learning\\nYear: 2013\\n\\nAbstract: Public libraries and coworking spaces seek for means to facilitate peer collaboration, peer inspiration and cross-pollination of skills and creativity. However, social learning, inspiration and collaboration between coworkers do not come naturally. In particular in (semi-) public spaces, the behavioural norm among unacquainted coworkers is to work in individual silos without taking advantage of social learning or collaboration opportunities. This paper presents results from a pilot study of 'Gelatine' -- a system that facilitates shared encounters between coworkers by allowing them to digitally 'check in' at a work space. Gelatine displays skills, areas of interest, and needs of currently present coworkers on a public screen. The results indicate that the system amplifies users' sense of place and awareness of other coworkers, and serves as an interface for social learning through exploratory, opportunistic and serendipitous inspirations, as well as through helping users identify like-minded peers for follow-up face-to-face encounters. We discuss how Gelatine is perceived by users with different pre-entry motivations, and discuss users' challenges as well as non-use of the system.\",\n \"Title: Designing for place-based social interaction of urban residents in México, South Africa and Australia\\nYear: 2006\\n\\nAbstract: The design of technology to facilitate social interaction of urban residents is increasingly important for many countries around the world. México and South Africa are particularly prone to issues that stem from urban densification and a lack of adequate affordable housing. Governments look to ICT to take on a mediating and facilitating role. This paper reports on research-inprogress of a tri-continental study. The external factors and aims of this pilot project identifying local case studies to prepare for a larger and longer term international comparison of local community networking approaches are examined. It is argued that by careful attention to cultural and social assets in the community, innovations will be engendered which enhance economic and social development. Preliminary design implications for the support of neighbourhood interactions across different socio-cultural contexts are presented.\",\n \"Title: Colour coding the fridge to reduce food waste\\nYear: 2012\\n\\nAbstract: This paper introduces the first iteration of a study aimed at grouping similar food types together in a refrigerator to increase the awareness of available foods for consumers in a domestic environment. The goals of the project are twofold: i) Raise the awareness of available foods for all members of a household; ii) Reduce the amount of expired food waste in the household. The project implemented a paper-based colour scheme in refrigerators in households, assigning colours to particular food types (e.g. green to fruit and vegetables, red to meat, etc.). The findings show that the colour coding raised participants' awareness of available food items in the fridge, particularly for those participants who were not directly involved in the shopping and initial storage of each food item. The findings also indicate that such awareness led to a reduction in expiration of food and thus general food waste in the household. These preliminary findings suggest that raising awareness of food availability through categorisation and efficient communication of this information may lead to a reduction in food waste in domestic environments.\",\n \"Title: Analyzing The Factors Influencing The Successful Design And Uptake Of Interactive Systems To Support Social Networks In Urban Neighborhoods\\nYear: 2006\\n\\nAbstract: In urban residential environments in Australia and other developed countries, Internet access is on the verge of becoming a ubiquitous utility like gas or electricity. From an urban sociology and community informatics perspective, this article discusses new emerging social formations of urban residents that are based on networked individualism and the potential of Internet-based systems to support them. It proposes that one of the main reasons for the disappearance or nonexistence of urban residential communities is a lack of appropriate opportunities and instruments to encourage and support local interaction in urban neighborhoods. The article challenges the view that a mere reappropriation of applications used to support dispersed virtual communities is adequate to meet the place and proximity-based design requirements that community networks in urban neighborhoods pose. It argues that the key factors influencing the successful design and uptake of interactive systems to support social networks in urban neighborhoods include the swarming social behavior of urban dwellers; the dynamics of their existing communicative ecology; and the serendipitous, voluntary, and place-based quality of interaction between residents on the basis of choice, like-mindedness, mutual interest and support needs. Drawing on an analysis of these factors, the conceptual design framework of a prototype system - the urban tribe incubator - is presented.\",\n \"Title: HCI for City Farms: Design Challenges and Opportunities.\\nYear: 2013\\n\\nAbstract: Urban agriculture plays an important role in many facets of food security, health and sustainability. The city farm is one such manifestation of urban agriculture: it functions as a location centric social hub that supplies food, education, and opportunities for strengthening the diverse sociocultural fabrics of the local community. This paper presents the case of Northey Street City Farm in Brisbane, Australia as an opportunity space for design. The paper identifies four areas that present key challenges and opportunities for HCI design that support social sustainability of the city farm: A preference for face-to-face contact leads to inconsistencies in shared knowledge; a dependence on volunteers and very limited resources necessitates easily accessible interventions; other local urban agricultural activity needing greater visibility; and the vulnerability of the physical location to natural phenomenon, in this instance flooding, present a design challenge and a need to consider disaster management.\",\n \"Title: Virtual fish: visual evidence of connectivity in a master-planned urban community\\nYear: 2007\\n\\nAbstract: The rapid densification of urban areas around the world offers exciting opportunities for new place-based artworks and locative media that aim at engaging, informing and entertaining members of local communities. In this paper, we introduce a design competition for concepts of interaction design which display visual evidence of connectivity in a master-planned community. This competition is based in and focuses on one of Brisbane's newly built inner urban renewal developments. Furthermore, we introduce the conceptual interaction design of one of the competition's winning entries, as well as its potential and its challenges to engage local residents in participation and exploration of place-based information and community media.\",\n \"Title: TrainRoulette: promoting situated in-train social interaction between passengers\\nYear: 2013\\n\\nAbstract: Travelling by public transport is usually regarded as boring and uninteresting. Refraining from talking to the stranger next to you may be due to limitations that are self-imposed and further corroborated by social expectations and cultural norms that govern behaviour in public space. Our design research into passenger interactions on board of urban commuter trains has informed the development of the TrainRoulette prototype -- a mobile app for situated, real-time chats between train passengers. We study the impact of our design intervention on shaping perceptions of the train journey experience. Moreover, we are interested in the implications of such ICT-mediated interactions within train journeys for stimulating social offline interactions and new forms of passenger engagement.\",\n \"Title: Towards visualising people's ecology of hybrid personal learning environments\\nYear: 2012\\n\\nAbstract: Ambient media architecture can provide place-based collaborative learning experiences and pathways for social interactions that would not be otherwise possible. This paper is concerned with ways of enhancing peer-to-peer learning affordances in library spaces; how can the library facilitate the community of library users to learn from each other? We report on the findings of a study that employed a participatory design method where participants were asked to reflect and draw places, social networks, and activities that they use to work (be creative, productive), play (have fun, socialize, be entertained), and learn (acquire new information, knowledge, or skills). The results illustrate how informal learning -- learning outside the formal education system -- is facilitated by a personal selection of physical and socio-cultural environments, as well as online tools, platforms, and networks. This paper sheds light on participants' individually curated ecologies of their work, play, and learning related networks and the hybrid (physical and digital) nature of these places. These insights reveal opportunities for ambient media architecture to increase awareness of and connections between people's hybrid personal learning environments.\",\n \"Title: People, content, location: sweet spotting urban screens for situated engagement\\nYear: 2012\\n\\nAbstract: A growing body of research is looking at ways to bring the processes and benefits of online deliberation to the places they are about and in turn allow a larger, targeted proportion of the urban public to have a voice, be heard, and engage in questions of city planning and design. Seeking to take advantage of the civic opportunities of situated engagement through public screens and mobile devices, our research informed a public urban screen content application DIS that we deployed and evaluated in a wide range of real world public and urban environments. For example, it is currently running on the renowned urban screen at Federation Square in Melbourne. We analysed the data from these user studies within a conceptual framework that positions situated engagement across three key parameters: people, content, and location. We propose a way to identify the sweet spot within the nexus of these parameters to help deploy and run interactive systems to maximise the quality of the situated engagement for civic and related deliberation purposes.\",\n \"Title: Suburban nostalgia: the community building potential of urban screens\\nYear: 2008\\n\\nAbstract: Urbanely nomadic residents are increasingly forgoing the potential of locale based serendipitous encounters in favour of digitally mediated interactions within their walled garden of existing social networks. This limits a sense of community in urban neighbourhoods to members of one's social network, but what of interactions with those outside of these networks, such as inhabitants of residential spaces? We report on our pilot study of open ended interviews which investigates the different user archetypes whose needs we consider when designing social technology for urban spaces. We propose a design to extend the sense of community in urban neighbourhoods beyond pure network sociality. Through a lens of 'suburban nostalgia' we envision how neighbourhood interactions might be retrofitted in new ways through civic engagement in the enhancement of environments.\",\n \"Title: The social car: new interactive vehicular applications derived from social media and urban informatics\\nYear: 2012\\n\\nAbstract: Digital information that is place- and time-specific, is increasingly becoming available on all aspects of the urban landscape. People (cf. the Social Web), places (cf. the Geo Web), and physical objects (cf. ubiquitous computing, the Internet of Things) are increasingly infused with sensors, actuators, and tagged with a wealth of digital information. Urban informatics research explores these emerging digital layers of the city at the intersection of people, place and technology. However, little is known about the challenges and new opportunities that these digital layers may offer to road users driving through today's mega cities. We argue that this aspect is worth exploring in particular with regards to Auto-UI's overarching goal of making cars both safer and more enjoyable. This paper presents the findings of a pilot study, which included 14 urban informatics research experts participating in a guided ideation (idea creation) workshop within a simulated environment. They were immersed into different driving scenarios to imagine novel urban informatics type of applications specific to the driving context.\",\n \"Title: Collective and network sociality in an urban village\\nYear: 2008\\n\\nAbstract: Our ongoing research program explores the communicative ecology of urban residents and the way these findings can inform design innovation of interactive web, mobile and geospatial applications and local communication services. This paper presents results of a study within this program that seeks to develop a better understanding of the way residents choose different types of web and mobile technology to oscillate between collective and networked interaction paradigms. The analysis of this data draws out key distinctions between collective and network sociality in place-based settings. It points in the direction of design opportunities for global web services to be translated and appropriated for local use to support everyday connections, place making efforts and participatory urbanism and citizenship.\",\n \"Title: Learning beyond books—strategies for ambient media to improve libraries and collaboration spaces as interfaces for social learning\\nYear: 2014\\n\\nAbstract: With the advent of digital media and online information resources, public libraries as physical destinations for information access are being increasingly challenged. As a response, many libraries follow the trend of removing bookshelves in order to provide more floorspace for social interaction and collaboration. Such spaces follow a Commons 2.0 model: they are designed to support collaborative work and social learning. The acquisition of skills and knowledge is facilitated as a result of being surrounded by and interacting with a community of likeminded others. Based on the results of a case study on a Commons 2.0 library space, this paper describes several issues of collaboration and social learning in public library settings. Acknowledging the significance of the architectural characteristics of the physical space, we discuss opportunities for ambient media to better reflect the social attributes of the library as a place; i.e. amplify the sense of other co-present library visitors and provide opportunities for shared encounters and conversations, which would remain invisible otherwise. We present the design of a user check-in system for improving the library as a physical destination for social learning, sharing, and inspiration for and by the community.\",\n \"Title: Participatory Data Analytics: Collaborative Interfaces for Data Composition and Visualisation\\nYear: 2014\\n\\nAbstract: This research proposes the development of interfaces to support collaborative, community-driven inquiry into data, which we refer to as Participatory Data Analytics. Since the investigation is led by local communities, it is not possible to anticipate which data will be relevant and what questions are going to be asked. Therefore, users have to be able to construct and tailor visualisations to their own needs. The poster presents early work towards defining a suitable compositional model, which will allow users to mix, match, and manipulate data sets to obtain visual representations with little-to-no programming knowledge. Following a user-centred design process, we are subsequently planning to identify appropriate interaction techniques and metaphors for generating such visual specifications on wall-sized, multi-touch displays.\",\n \"Title: Technicolouring the fridge: reducing food waste through uses of colour-coding and cameras\\nYear: 2014\\n\\nAbstract: Domestic food wastage is a growing problem for the environment and food security. Some causes of domestic food wastes are attributed to a consumer's behaviours during food purchasing, storage and consumption, such as: excessive food purchases and stockpiling in storage. Recent efforts in human-computer interaction research have examined ways of influencing consumer behaviour. The outcomes have led to a number of interventions that assist users with performing everyday tasks. The Internet Fridge is an example of such an intervention. However, new pioneering technologies frequently confront barriers that restrict their future impact in the market place, which has prompted investigations into the effectiveness of behaviour changing interventions used to encourage more sustainable practices. In this paper, we investigate and compare the effectiveness of two interventions that encourage behaviour change: FridgeCam and the Colour Code Project. We use FridgeCam to examine how improving a consumer's food supply knowledge can reduce food stockpiling. We use the Colour Code Project to examine how improving consumer awareness of food location can encourage consumption of forgotten foods. We explore opportunities to integrate these interventions into commercially available technologies, such as the Internet Fridge, to: (i) increase the technology's benefit and value to users, and (ii) promote reduced domestic food wastage. We conclude that interventions improving consumer food supply and location knowledge can promote behaviours that reduce domestic food waste over a longer term. The implications of this research present new opportunities for existing and future technologies to play a key role in reducing domestic food waste.\",\n \"Title: Vote With Your Feet: Local Community Polling on Urban Screens\\nYear: 2014\\n\\nAbstract: Falling prices have led to an ongoing spread of public displays in urban areas. Still, they mostly show passive content such as commercials and digital signage. At the same time, technological advances have enabled the creation of interactive displays potentially increasing their attractiveness for the audience, e.g. through providing a platform for civic discourse. This poses considerable challenges, since displays need to communicate the opportunity to engage, motivate the audience to do so, and be easy to use. In this paper we present Vote With Your Feet, a hyperlocal public polling tool for urban screens allowing users to express their opinions. Similar to vox populi interviews on TV or polls on news websites, the tool is meant to reflect the mindset of the community on topics such as current affairs, cultural identity and local matters. It is novel in that it focuses on a situated civic discourse and provides a tangible user interface, tackling the mentioned challenges. It shows one Yes/No question at a time and enables users to vote by stepping on one of two tangible buttons on the ground. This user interface was introduced to attract people's attention and to lower participation barriers. Our field study showed that Vote With Your Feet is perceived as inviting and that it can spark discussions among co-located people.\",\n \"Title: UbiOpticon: Participatory Sousveillance with Urban Screens and Mobile Phone Cameras\\nYear: 2014\\n\\nAbstract: In many cities around the world, surveillance by a pervasive net of CCTV cameras is a common phenomenon in an attempt to uphold safety and security across the urban environment. Video footage is being recorded and stored, sometimes live feeds are being watched in control rooms hidden from public access and view. In this study, we were inspired by Steve Mann's original work on sousveillance (surveillance from below) to examine how a network of camera equipped urban screens could allow the residents of Oulu in Finland to collaborate on the safekeeping of their city. An agile, rapid prototyping process led to the design, implementation and 'in the wild' deployment of the UbiOpticon screen application. Live video streams captured by web cams integrated at the top of 12 distributed urban screens were broadcast and displayed in a matrix arrangement on all screens. The matrix also included live video streams of two roaming mobile phone cameras. In our field study we explored the reactions of passers-by and users of this screen application that seeks to inverse Bentham's original panopticon by allowing the watched to be watchers at the same time. In addition to the original goal of participatory sousveillance, the system's live video feature sparked fun and novel user-led apprlopriations.\",\n \"Title: DIY media architecture: open and participatory approaches to community engagement\\nYear: 2014\\n\\nAbstract: Media architecture's combination of the digital and the physical can trigger, enhance, and amplify urban experiences. In this paper, we examine how to bring about and foster more open and participatory approaches to engage communities through media architecture by identifying novel ways to put some of the creative process into the hands of laypeople. We review technical, spatial, and social aspects of DIY phenomena with a view to better understand maker cultures, communities, and practices. We synthesise our findings and ask if and how media architects as a community of practice can encourage the 'open-sourcing' of information and tools allowing laypeople to not only participate but become active instigators of change in their own right. We argue that enabling true DIY practices in media architecture may increase citizen control. Seeking design strategies that foster DIY approaches, we propose five areas for further work and investigation. The paper begs many questions indicating ample room for further research into DIY Media Architecture.\",\n \"Title: Pervasive Computing and Environmental Sustainability: Two Conference Workshops\\nYear: 2009\\n\\nAbstract: Raising people's awareness with environmental data and educational information does not necessarily trigger sufficient motivation to change their habits towards a more environmentally friendly and sustainable lifestyle. This article reports on two workshops at Pervasive 2008 and UbiComp 2008 that sought to develop a better understanding how to go beyond just informing and into motivating and encouraging action and change. Drawing on participatory culture, ubiquitous computing, and real-time information, participants discussed research and development of viable new design approaches and information interfaces that can strengthen our position to meet the targets of the Kyoto protocol, and contribute to the sustainability of a low-carbon future.\",\n \"Title: Darkness and Disaster in the City\\nYear: 2011\\n\\nAbstract: People all over the world are regularly hit by floods, cyclones, and other natural disasters. Many use smart phones and social media to stay connected, seek help, improvise, and cope with crises or challenging situations. This column discusses these practices after dark or during disasters to unveil challenges and opportunities for innovative designs that increase resilience and safety.\",\n \"Title: Digital cities 9 workshop - hackable cities: from subversive city making to systemic change\\nYear: 2015\\n\\nAbstract: The DC9 workshop takes place on June 27, 2015 in Limerick, Ireland and is titled \\\\\\\"Hackable Cities: From Subversive City Making to Systemic Change\\\\\\\". The notion of \\\\\\\"hacking\\\\\\\" originates from the world of media technologies but is increasingly often being used for creative ideals and practices of city making. \\\\\\\"City hacking\\\\\\\" evokes more participatory, inclusive, decentralized, playful and subversive alternatives to often top-down ICT implementations in smart city making. However, these discourses about \\\\\\\"hacking the city\\\\\\\" are used ambiguously and are loaded with various ideological presumptions, which makes the term also problematic. For some \\\\\\\"urban hacking\\\\\\\" is about empowering citizens to organize around communal issues and perform aesthetic urban interventions. For others it raises questions about governance: what kind of \\\\\\\"city hacks\\\\\\\" should be encouraged or not, and who decides? Can city hacking be curated? For yet others, trendy participatory buzzwords like these are masquerades for deeply libertarian neoliberal values. Furthermore, a question is how \\\\\\\"city hacking\\\\\\\" may mature from the tactical level of smart and often playful interventions to the strategic level of enduring impact. The Digital Cities 9 workshop welcomes papers that explore the idea of \\\\\\\"hackable city making\\\\\\\" in constructive and critical ways.\",\n \"Title: Vote as you go: blending interfaces for community engagement into the urban space\\nYear: 2015\\n\\nAbstract: This paper presents a series of studies on situated interfaces for community engagement. Firstly, we identify five recurring design challenges as well as four common strategies used to overcome them. We then assess the effectiveness of these strategies through field studies with public polling interfaces. We developed two very different polling interfaces in the form of (1) a web application running on an iPad mounted on a stand, allowing one vote at a time, and (2) a playful full-body interaction application for a large urban screen allowing concurrent participation. We deployed both interfaces in an urban precinct with high pedestrian traffic and equipped with a large urban screen. Analysing discoverability and learnability of each scenario, we derive insights regarding effective ways of blending community engagement interfaces into the built environment, while attracting the attention of passers-by and communicating the results of civic participation.\",\n \"Title: Collaborative Data Exploration Interfaces - From Participatory Sensing to Participatory Sensemaking\\nYear: 2015\\n\\nAbstract: As technological capabilities for capturing, aggregating, and processing large quantities of data continue to improve, the question becomes how to effectively utilise these resources. Whenever automatic methods fail, it is necessary to rely on human background knowledge, intuition, and deliberation. This creates demand for data exploration interfaces that support the analytical process, allowing users to absorb and derive knowledge from data. Such interfaces have historically been designed for experts. However, existing research has shown promise in involving a broader range of users that act as citizen scientists, placing high demands in terms of usability. Visualisation is one of the most effective analytical tools for humans to process abstract information. Our research focuses on the development of interfaces to support collaborative, community-led inquiry into data, which we refer to as Participatory Data Analytics. The development of data exploration interfaces to support independent investigations by local communities around topics of their interest presents a unique set of challenges, which we discuss in this paper. We present our preliminary work towards suitable high-level abstractions and interaction concepts to allow users to construct and tailor visualisations to their own needs.\",\n \"Title: Ad hoc communities on the road: Serendipitous social encounters to enhance tourist experiences\\nYear: 2015\\n\\nAbstract: Driving can be a lonely activity. While there has been a lot of research and technical inventions concerning car-to-car communication and passenger entertainment, there is still little work concerning connecting drivers. Whereas tourism is very much a social activity, drive tourists and road trippers have few options to communicate with fellow travelers. Our study is placed at the intersection of tourism and driving. It aims to enhance the trip experience during driving through social interaction. This paper explores how a mobile application that allows instant messaging between travelers sharing similar context can establish a temporary, ad hoc community and enhance the road trip experience. A prototype was developed and evaluated in various user and field studies. The study's outcomes are relevant for the design of future mobile tourist guides that benefit from community design, social encounters and recommendations.\",\n \"Title: TrainYarn: Probing perceptions of social space in urban commuter trains\\nYear: 2015\\n\\nAbstract: We studied the ways that urban commuter train passengers experience their journeys. We present the design process and in-situ evaluation of TrainYarn, a mobile app prototype designed to facilitate social interaction between co-located urban train passengers. Through the deployment of the prototype, we sought to probe perceptions of social space with a view to positively impact the assessment of public transport. Our results support that our target users saw value in the use of TrainYarn, perceiving it as emancipatory, in alignment with their communicative needs, and having the ability to transform their perceptions of social space. To further inform future research and practice, we put forward a series of design recommendations.\",\n \"Title: From users to citizens: Some thoughts on designing for polity and civics\\nYear: 2015\\n\\nAbstract: This paper presents an essay aimed at prompting broad discussion crucial in keeping the interaction design discourse fresh, critical, and in motion. We trace the changing role of people who have advanced from consumers to producers, from stationary office workers to mobile urban nomads, from passive members of the plebs to active instigators of change. Yet, interaction designers often still refer to them only as 'users.' We follow some of the historic developments from the information superhighway to the smart city in order to provide the backdrop in front of which we critically analyse three core areas. First, the issue of echo chambers and filter bubbles in social media results in a political polarisation that jeopardises the formation of a functioning public sphere. Second, pretty lights and colourful façades in media architecture are increasingly making way for situated installations and interventions fostering community engagement. And third, civic activism is often reduced to forms of slacktivism. We synthesise our discussion to propose 'citizen-ability' as an alternative goal for interaction designers to aspire to in order to create new polities and civics for a better quality of life.\",\n \"Title: Urban Informatics beyond Data: Media Architecture, Placemaking, and Citizen Action\\nYear: 2015\\n\\nAbstract: Since 2006, we have been conducting urban informatics research that we define as \\\\\\\"the study, design, and practice of urban experiences across different urban contexts that are created by new opportunities of real-time, ubiquitous technology and the augmentation that mediates the physical and digital layers of people networks and urban infrastructures\\\\\\\" [1]. Various new research initiatives under the label \\\\\\\"urban informatics\\\\\\\" have been started since then by universities (e.g., NYU's Center for Urban Science and Progress) and industry (e.g., Arup, McKinsey) worldwide. Yet, many of these new initiatives are limited to what Townsend calls, \\\\\\\"data-driven approaches to urban improvement\\\\\\\" [2]. One of the key challenges is that any quantity of aggregated data does not easily translate directly into quality insights to better understand cities. In this talk, I will raise questions about the purpose of urban informatics research beyond data, and show examples of media architecture, participatory city making, and citizen activism. I argue for (1) broadening the disciplinary foundations that urban science approaches draw on; (2) maintaining a hybrid perspective that considers both the bird's eye view as well as the citizen's view, and; (3) employing design research to not be limited to just understanding, but to bring about actionable knowledge that will drive change for good.\",\n \"Title: Citizens breaking out of filter bubbles: urban screens as civic media.\\nYear: 2016\\n\\nAbstract: Social media platforms risk polarising public opinions by employing proprietary algorithms that produce filter bubbles and echo chambers. As a result, the ability of citizens and communities to engage in robust debate in the public sphere is diminished. In response, this paper highlights the capacity of urban interfaces, such as pervasive displays, to counteract this trend by exposing citizens to the socio-cultural diversity of the city. Engagement with different ideas, networks and communities is crucial to both innovation and the functioning of democracy. We discuss examples of urban interfaces designed to play a key role in fostering this engagement. Based on an analysis of works empirically-grounded in field observations and design research, we call for a theoretical framework that positions pervasive displays and other urban interfaces as civic media. We argue that when designed for more than wayfinding, advertisement or television broadcasts, urban screens as civic media can rectify some of the pitfalls of social media by allowing the polarised user to break out of their filter bubble and embrace the cultural diversity and richness of the city.\",\n \"Title: Social Living Labs for Digital Participation: Designing with Regional and Rural Communities.\\nYear: 2016\\n\\nAbstract: \\\\\\\"Fostering digital participation through Living Labs in regional and rural Australian communities,\\\\\\\" is a three year research project funded by the Australian Research Council. The project aims to identify the specific digital needs and practices of regional and rural residents in the context of the implementation of high speed internet. It seeks to identify new ways for enabling residents to develop their digital confidence and skills both at home and in the community. This two-day symposium will bring together researchers and practitioners from diverse backgrounds to discuss design practices in social living labs that aim to foster digital inclusion and participation. Day one will consist of practitioner and research reports, while day two will provide an opportunity for participants to imagine and design future digital participation strategies. Academic participants will also have an opportunity to contribute to a refereed edited volume by Chandos Publishing (an imprint of Elsevier).\",\n \"Title: The role of passenger-centric innovation in the future of public transport.\\nYear: 2016\\n\\nAbstract: Although hard factors such as availability, efficiency, safety, and comfort make up the core of the public transport quality of service, they are only a part of the bigger picture. This bigger picture is modified and shaped daily, where the increasing permeation of technology creates new possibilities for passengers to experience their journeys. Despite technology becoming ubiquitous in public transport, it has had only limited impact on how passengers connect affectively and symbolically with the service. This “affective gap” is at the core of what differentiates private and public transport. Being able to reduce this gap is therefore valuable to passengers and public transport service providers alike. In this paper, we build on existing and ongoing work to discuss the relevance of a passenger-centric approach to innovation in the field of public transport. This passenger-centric approach puts passengers at the centre of future solutions, where their evolving needs, desires, and values are used to guide how to enhance the existing core functionality of the service. To test our hypothesis that passenger-centric innovation is valuable to passengers and advantageous to service providers alike, we put forward a review on how innovation is being approached in both the aviation and car industries. This review is supported by our own insights, which have been based on data collected from urban rail commuters in Australia. We further support our argument by looking at particular examples of innovation in the field of public transport, and discussing the existing barriers and drivers that can, respectively, hinder or propel passenger-centric innovation.\",\n \"Title: Glance: generalized geometric primitives and transformations for information visualization in AR/VR environments.\\nYear: 2016\\n\\nAbstract: This paper outlines Glance, a unifying framework for exploring multidimensional, multivariate data in the context of AR/VR environments, along with specific implementation techniques that utilize programmable GPUs. The presented techniques extend the graphics pipeline through programmable shaders in order to support more general geometries and operations. Our point of departure from existing structural theories of graphics is a general spatial substrate, where data is encoded using higher-dimensional geometric primitives. From there, we define a series of processing stages, utilizing shaders to enable flexible and dynamic coordinate transformations. Furthermore, we describe how advanced visualization techniques, such as faceting and multiple views, can be integrated elegantly into our model. Bridging between Computer Graphics and Information Visualization theories, the elements of our framework are composable and expressive, allowing a diverse set of visualizations to be specified in a universal manner (see figure 1).\",\n \"Title: Grids and networks: two exploratory approaches for visualising bibliometric data on very large displays.\\nYear: 2016\\n\\nAbstract: Current personal single-user devices, such as smartphones, tablets, or laptops, struggle to provide the contextual awareness and coordination capabilities required for the effective collaborative analysis of large datasets. Instead, large interactive displays offer unique opportunities for co-located collaboration in meeting room environments. However, supporting collaborative interaction across multiple large displays presents distinctive challenges for interaction designers. This paper explores and compares novel interaction techniques and visualisations for large displays, with a focus on two distinct approaches for collaborative browsing and filtering of multivariate datasets: (i) shared zoomable grid view, and (ii) multiple individual network views. In order to evaluate the effectiveness of our proposed interfaces for multi-user exploratory analysis, we applied the designs to a specific use case, namely the problem of displaying research metadata from bibliographic databases to extract and collate narratives and overarching themes for research grant proposals. Following an agile design methodology, we created two prototypes incorporating our designs. We weigh the benefits and limitations of each approach by comparing them along two key dimensions: (i) methods of interaction, and (ii) visual representation. Subsequently, we compare the two design approaches and discuss the circumstances and situations that would be beneficial for use. This research and its implications are intended to inform future research exploring the design of collaborative interfaces for large-scale interaction environments.\",\n \"Title: Exploring tangible interaction for map-based feedback.\\nYear: 2016\\n\\nAbstract: This paper describes the development of a series of tangible feedback mechanisms for an analogue map-based feedback interface. By prototyping interactions with simple everyday analogue materials, the goal was to explore playful, tangible input methods for our interface, beyond a more conventional screen-based approach that could inform future development of a digital map-based feedback interface. Four different prototype interactions were developed that could work in a completely analogue implementation. These interactions were installed and evaluated as part of an in-the-wild deployment of a larger project, which was used as part of a community consultation process. By analysing how people used our interaction prototypes and the feedback that they left, data was collected to inform later iterations with the kinds of interaction approaches that can successfully engage participants and the most effective methods of soliciting feedback.\",\n \"Title: CrowdRisk: exploring crowdsourcing of risk information.\\nYear: 2016\\n\\nAbstract: This paper describes the outcomes of a preliminary study into the design of a mobile app to crowdsource information related to \\\\\\\"risk\\\\\\\". For the purpose of this study the notion of risk is defined broadly; however, we predominantly focus on the personal, subjective perception of risk. The study involved building a prototypical mobile app to crowdsource risk and exploring the use of the app as part of an expert workshop. Outcomes show challenges and opportunities with regards to the categorisation of results, the motivation of users, and interaction design of the prototype. The study provides value by giving an initial insight into this design space.\",\n \"Title: Designing Gamified Applications that Make Safe Driving More Engaging.\\nYear: 2017\\n\\nAbstract: Low levels of engagement while driving can pose road safety risks, e.g., inattention during low traffic or routine trips. Interactive technologies that increase task engagement could therefore offer safety benefits, e.g., through performance feedback, increased challenge, and incentives. As a means to build upon these notions, we chose to explore gamification of the driving task. The research aim was to study how to design gamified applications that make safe driving more engaging. We present six design lenses which bring into focus considerations most relevant to creating engaging car applications. A user study enhanced our understanding of design requirements and revealed user personas to support the development of such applications. These lenses and personas informed two prototypes, which we evaluated in driving simulator studies. Our results indicate that the gamified conditions increased driver engagement and reduced driving speeds. As such, our work contributes towards the design of engaging applications that are both appropriate to the safety-critical driving context and compelling to users.\",\n \"Title: The promise of blockchain technology for interaction design.\\nYear: 2017\\n\\nAbstract: After its first prominent application as part of the digital currency Bitcoin, blockchain technology is gaining in popularity. It comprises a chain of blocks (the ledger) that provides a secure, immutable and auditable list of ordered records. Using both cryptography and a distributed database, once a block is recorded, it can no longer be changed. In Bitcoinu0027s case, the ledger contains the history of all currency transactions. This paper offers a critical overview of the blockchain technology for an interaction design audience, in three parts: (1) The principles making block-chain technology possible are briefly explained using examples. (2) Specific cases such as food provenance and supply chain tracing, are used to illustrate both the wide array of possible applications and the profound implications of blockchain technology. (3) Opportunities and challenges for HCI and interaction design are discussed in the form of a nascent research agenda.\",\n \"Title: The work of making: reflections on the process, form and function of two sets of design research artefacts.\\nYear: 2017\\n\\nAbstract: In this paper we present a reflexive account of the development of two separate Research-through-Design studies. We draw from the experience of designing and creating two separate sets of design research artefacts that fit within a broader study into everyday domestic life. The paperu0027s contribution is structured around three elements relating to the development of design research artefacts and the: 1) Participants; 2) Researchers; 3) Study. It further aims to emphasise the need for a range of documentation on the diverse approaches researchers take within their design processes.\",\n \"Title: Rat running the G20: collective intelligence for navigating the disrupted city.\\nYear: 2018\\n\\nAbstract: Large-scale political or cultural events in urban environments disrupt and challenge city residents in making informed decisions to navigate through restricted zones. However, little research exists that examines how residents successfully overcome the mobility turmoils created by such events. Studies into collective intelligence found socio-technical efforts that can assist citizens in dealing with challenging situations in urban environments. Yet, studies into other forms of collective and network sociality and how those forms are interwoven with the social construction of urban space, are rare. In this paper, we present data from the 2014 G20 Summit held in Brisbane, Australia, to propose that collective-informed decisions made by urban residents in disrupted environments are influenced by particular communication patterns and information access, as well as the production and reproduction of urban imaginaries. An urban exploration as the G20 event unfolded, followed by audio-recorded focus groups, was conducted with 14 participants who mapped their walks through the city using a mobile app and captured images of different locations along their paths. The analysis of these data contributes towards a deeper understanding of collective intelligence strategies for citizens interacting with urban space and gives rise to potential strategies for enhancing socio-spatial engagement of urban residents.\",\n \"Title: Creativity and design to articulate difference in the conflicted city: collective intelligence in Bogota's grassroots organisations.\\nYear: 2018\\n\\nAbstract: This paper presents a critical reflection on insights into the ongoing endeavours for community engagement by Ayara and MAL; two urban grassroot organisations in Bogota, Colombia, where a long history of internal conflicts has resulted in diverse human right violations. The paper presents examples of the grassroots organisations’ unique methods of engagement that promotes building collective intelligence from the bottom–up through creative collaboration and design processes, leading to rebuilding social fabrics that support the common good for the people of Bogota.\",\n \"Title: DoGood: examining gamification, civic engagement, and collective intelligence.\\nYear: 2018\\n\\nAbstract: The mobile internet provides new and easier ways for people to organise themselves, raise issues, take action, and interact with their city. However, lack of information or motivation often prevents citizens from regularly contributing to the common good. In this paper, we present DoGood, a mobile app that aims at motivating citizens to join civic activities in their local community. Our study asks to what extent gamification can motivate users to participate in civic activities. The term civic activity is not yet well defined, so we collect activities citizens consider to be civic to work towards a broadly accepted definition of the term. The DoGood app uses gamified elements that we studied to gauge their role in encouraging citizens to submit and promote their civic activities as well as to join the activities of others. DoGood was implemented and deployed to citizens in a five-week-long user study. The app succeeded in motivating most of its users to do more civic activities, and its gamified elements were well received.\",\n \"Title: On Scale, Dialectics, And Affect: Pathways For Proliferating Participatory Design\\nYear: 2018\\n\\nAbstract: The Participatory Design (PD) community is committed to continuously refine its technological, social, political, and scientific agenda, and as a result, PD has become more widely adopted, robust, and sophisticated. Yet, PD's advancement cannot end here. The gap between those who can contribute to the shaping of future technologies and those who are reduced to consumers, has - if anything - widened on a grand scale. In response, we argue through three lenses: scale, dialectics, and affect in PD, and suggest some pathways to build bridges, foster alliances, and evolve PD practice to proliferate the democratisation in technology design that has been a strong value driving PD. Scale asks about ways for PD to extend its reach without giving up on its core qualities. Dialectics is about creating and maintaining the spaces and fora for constructive conflict by networking and linking with other stakeholders, organisations, and domains. Finally, affect discusses how PD can put forward democratic visions of technological futures that connect to people's hearts, acknowledging that decisions are often made irrationally and unconsciously. Our review draws attention to opportunities for PD to travel between different contexts and proliferate through interconnected and intermediary knowledge and an embodied literacy that enables PD to reach further into industry, government, and community.\",\n \"Title: More-than-human urban futures: speculative participatory design to avoid ecocidal smart cities.\\nYear: 2018\\n\\nAbstract: We propose a collective participatory speculative urban walk exploring more-than-human perspectives for smart cities. The walk will be a curated selection of outcomes from a PDC workshop interrogating how more-than-human approaches and their resultant ethical, legal, and methodological concerns can shape participatory design practices toward cohabitation. Our aim with the Situated Action is to use the walk as an embodied approach to push forward a cultural change in the agenda of sustainable smart cities, urban informatics and IoT. The walk will draw from the specificity of urban infrastructures in Hasselt associated with more-than-human approaches and include a selection of provisional artefacts in the form of low-fi prototypes, manifestos or future scenarios from the workshop to scaffold participation within the urban environment for conference delegates and citizens.\",\n \"Title: Avoiding ecocidal smart cities: participatory design for more-than-human futures.\\nYear: 2018\\n\\nAbstract: The turn to participation in smart cities was intended to increase the involvement of diverse, often marginalised, citizens in the design and use of networked sensing technologies. However, ideals of activism, citizen engagement and democratisation through the co-design of networked technologies and services have been largely based on an understanding of urban space as separate from nature, and for human inhabitants alone. In current conditions of climate change, pollution, and loss of biodiversity, a human-centred perspective of cities is increasingly problematic. This workshop focuses on an expanded more-than-human perspective for cities, informed by studies in the Anthropocene in fields such as STS, geography, planning and design. We will interrogate how more-than-human perspectives and their resultant ethical, legal, and methodological concerns can shape participatory design practices and policies towards cohabitation, and push forward a cultural change in the agenda of sustainable smart cities, urban informatics, IoT, and design.\",\n \"Title: More-than-Human Media Architecture\\nYear: 2018\\n\\nAbstract: We consider some of the planetary conditions and global circumstances that both research and practice of media architecture are embedded within, such as climate change, pollution, resource consumption, and loss of biodiversity. While there has been a notable increase in emphasis on participation and engagement in design and use, with the aim to increase the involvement of diverse and often marginalised citizens, a human-centred approach to media architecture comes with its own set of problems. In this paper, we want to draw the attention of the media architecture community to the fallacy of human exceptionalism and anthropocentrism. We present a critical review of examples of media architecture projects and installations that question our understanding of urban space as separate from nature, and designed primarily for humans and just humans. Informed by studies in disciplines such as science and technology studies, critical geography, urban planning, and interaction design, we use insights derived from our review to discuss ways towards a more-than-human approach to media architecture. We conclude by proposing for discussion nascent design considerations for media architecture to go beyond the needs of just humans and to consider new ways to appreciate and cater for our broader ecological entanglements with plants, animals, and the environment at large.\",\n \"Title: More-than-human participation: design for sustainable smart city futures.\\nYear: 2019\\n\\nAbstract: In this forum we highlight innovative thought, design, and research in the area of interaction design and sustainability, illustrating the diversity of approaches across HCI communities. --- Roy Bendor, Editor\",\n \"Title: The Premise of Institutioning for the Proliferation of Communities and Technologies Research\\nYear: 2019\\n\\nAbstract: The role of institutions both as stakeholders in the work that communities and technologies (C&T;) researchers are engaged in and as facilitators for ensuring continuity and scale-making of outcomes, impact and community benefits, is starting to be revisited. This paper connects the debate in the C&T; community about its relevance and ongoing remit, with debates in the participatory design field about the role of the triad of infrastructuring, commoning, and more recently institutioning. In doing so, it considers the premise of institutioning for the proliferation of C&T; research. After a review of institutionalism and its foundational application to these discussions, the paper offers a conceptual framework that illustrates both the triad's interrelatedness and the need for orienting future C&T; efforts away from depoliticisation and towards a more active pursuit of targeting meso- and macro-levels of community institutions, political framing, and planetary impact.\",\n \"Title: From premise to practice of social consensus: How to agree on common knowledge in blockchain-enabled supply chains\\nYear: 2021\\n\\nAbstract: Attaining \\\"Common Knowledge\\\" is essential in the formation of deals and agreements, but is hard to achieve over point-to-point communication networks such as the Internet. While blockchain technologies provide a helpful mechanism in the form of technical consensus, originally created to resolve the double-spending problem, little does it address impediments to proper contract formation that have to do with the quality of exogenous data, asymmetry of information, or even its suitability (the colloquial garbage-in/garbage-out problem). In the face of the limitations of technical consensus, we explore how the strengths of technical consensus can be utilized by introducing another dimension of consensus - what we have called social consensus - which directly addresses the formation of true (if retrospective) Common Knowledge essential to arms-length agreement between multiple actors. We have eschewed the notion that social consensus as an epistemological concern, and instead focus on mechanisms by which environments of multiple actors form and sustain bodies of information that enable them to go about their activities with a reasonable level of confidence that others in the supply chain will 'do their bit,' backed by a 'failsafe' mechanism enforced by cryptography which holds the actors unharmed in case the envisioned finality is not obtained. These bodies of information create what is essentially a retrospective form of common knowledge, and a lesser variant, mutual knowledge. We propose an implementation from the preferred mechanism of a multisig primitive, which builds and improves on the Gnosis multisig, in the use case of decentralized blockchain-powered supply chains consisting of multiple parties, human and machine.\",\n \"Title: Garbage in garbage out: The precarious link between IoT and blockchain in food supply chains\\nYear: 2022\\n\\nAbstract: •Presents a theoretical argument based on a study of Australia-China beef exports.•Critiques data quality and validity assumptions in many IoT and blockchain systems.•Changes oracle identity and data validity practices using ‘common knowledge’ notion.•Limits possible capricious claims on IoT data performance in blockchain systems.•Proposes mechanism design for data to become lead indicators of desired future states.\",\n \"Title: Non-human Personas: Including Nature in the Participatory Design of Smart Cities\\nYear: 2021\\n\\nAbstract: For the past decades humans have been placed at the centre of designing information and communication technologies (ICT), leading to the rise in prominence of human-centred design. The field of smart cities has equally adopted notions of citizen participation as a way to ensure that technological solutions improve people's livelihoods. However, these kinds of processes treat the urban environment as separate from nature, promoting human comfort and convenience over planetary health and wellbeing. Motivated by these growing concerns that highlight the urgency to reconsider how we define and practice participation in smart cities and in human-centred ICT solutions more broadly, this article assesses how the personas method can be adapted to include more-than-human perspectives in the design process. Based on a case study, which involved designing smart urban furniture for human and non-human use, we introduce a framework for developing and employing non-human personas. As a key element of the framework, we describe a middle-out approach for forming a coalition that can speak on behalf of the non-human species that are impacted by design decisions. We demonstrate how the framework can be used through its retrospective application on two research-led smart city projects. The article concludes with a discussion of key principles for creating and using non-human personas in design projects.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":74,"string":"74"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13357,"string":"13,357"}}},{"rowIdx":13358,"cells":{"question_id":{"kind":"string","value":"Rossana M C Andrade"},"question":{"kind":"string","value":"Generate an abstract for the title \"A Set of Tools to Generate Intelligent Agents for Fault Prediction in Optical Rerouting\" using the following items: GMPLS, 1+1 protection mechanism, intelligent agents, artificial neural networks, fault prediction."},"answer":{"kind":"string","value":"One of the issues that constrains the use of GMPLS protocol in DWDM links is the slow rerouting provided by GMPLS over DWDM net- works.The 1+1 protection mechanism is an approach to solve it, where a backup link is employed as mirror to provide an immediate fault recovery. However, such solution is costly since a given channel must exclusively be allocated. In- telligent agents can execute the task of monitoring an optical link of a network, and aiming to predict anomalous situations, so that pro-active measures can be taken before faults occur. Thus, this paper presents a set of tools for generating such intelligent agents using Artificial Neural Networks. The use of intelligent agents leads to an algorithm for fault prediction with few computation resources and low complexity."},"correct_answer":{"kind":"string","value":"One of the issues that constrains the use of GMPLS protocol in DWDM links is the slow rerouting provided by GMPLS over DWDM net- works.The 1+1 protection mechanism is an approach to solve it, where a backup link is employed as mirror to provide an immediate fault recovery. However, such solution is costly since a given channel must exclusively be allocated. In- telligent agents can execute the task of monitoring an optical link of a network, and aiming to predict anomalous situations, so that pro-active measures can be taken before faults occur. Thus, this paper presents a set of tools for generating such intelligent agents using Artificial Neural Networks. The use of intelligent agents leads to an algorithm for fault prediction with few computation resources and low complexity."},"documents":{"kind":"list like","value":["Title: PEARL: A PErformance evaluAtor of cRyptographic aLgorithms for Mobile Devices\nYear: 2004\n\nAbstract: Limited computational power imposes new challenges during the implementation of security and privacy solutions for mobile devices. The choice for the most appropriate cryptographic algorithm for each mobile device has become a critical factor. In this paper, we present an approach for performance evaluation of cryptographic algorithms for mobile devices. A tool called PEARL (PErformance evaluAtor of cryptogRaphic aLgorithms for mobile devices) is also introduced in this work to validate the approach. This tool collects and analyzes information related to executions of the cryptographic algorithms in the mobile devices. Moreover, PEARL allows evaluating the performance of symmetrical and asymmetrical cryptographic algorithms, and hash functions for the J2ME platform.","Title: A Verification Mechanism of Feature Models for Mobile and Context-Aware Software Product Lines\nYear: 2011\n\nAbstract: Software Product Lines (SPLs) have been used to develop mobile and context-aware applications, which provide services and data for their users from anywhere and at any time using context information. In SPLs, commonality and variability of a system family are identified and often documented in a feature model. However, the development of a feature model for mobile and context-aware SPLs is not trivial, since it should comprise system and context information. Furthermore, the consistency check of feature models in the considered domain is also complex and demands advanced skills of software engineers. This paper proposes a mechanism to formalize and verify the correctness and consistency of feature models for mobile and context-aware SPLs based on a profile enriched with OCL specifications.","Title: A Coordination Framework For Dynamic Adaptation In Ubiquitous Systems Based On Distributed Tuple Space\nYear: 2013\n\nAbstract: The evolution of mobile technologies allows the emerging of ubiquitous systems, able to anticipate user needs and to seamlessly adapt to context changes. These systems present the problem of dynamic adaptation in a highly distributed, heterogeneous and volatile environment, since it may be difficult to collect and process context information from distributed unknown sources. In order to facilitate the development of such systems, this paper extends an existing coordination framework based on tuple spaces, aiming at the management of distributed information. Hence, a decentralized coordination framework was created, offering primitives to developers to create ubiquitous systems able to interact and cooperate in scenarios of total decentralization. This paper reports some experimental results obtained in a testbed of smartphones and tablets which demonstrate the practical feasibility of our approach and pointed out how our solution can grant context data dissemination in ad hoc and infrastructured networks.","Title: FRAMESEC: A Framework for the Application Development with End-to-End Security Provision in the Mobile Computing Environment\nYear: 2005\n\nAbstract: Mobile devices offer network connectivity through wireless system communication that makes possible for applications to get access to information at any time and any place. However, the wireless link is more vulnerable to pas- sive and active attacks than the fixed medium in the traditional networks. Then, this kind of connectivity brings security problems to the applications that deal with confidential data, such as mobile commerce. Although wireless communi- cation systems, such as IEEE 802.11, implement protection mechanisms for data transmission, they have reported vulnerabilities and do not guarantee end- to-end security, which is desirable for these applications. Thus, this work pro- poses an application framework that provides a reusable structure with security mechanisms, which enable end-to-end security in the mobile computing envi- ronment.","Title: A software product line for the mobile and context-aware applications domain\nYear: 2010\n\nAbstract: The mobile and context-aware application domain presents challenging requirements to software development. Although several solutions have been proposed for this type of application, reuse is not systematically used throughout the software development lifecycle. Then, in this paper we propose an approach for the development of a mobile and context-aware Software Product Line (SPL). A SPL for the mobile and context-ware mobile guide domain is presented in order to illustrate the steps of the proposed approach. Furthermore, the lessons learned in the SPL development are discussed. Both approach and SPL are the main contributions of this paper.","Title: A strategy for memory traffic management of bitmap fonts for text visualization in mobile devices\nYear: 2008\n\nAbstract: Document viewer and browser applications have gained attention in the mobile scenario due to the improvement on accessibility and portability of different kinds of information. However, mobile devices are still limited in relation to memory size, processing capacity and battery. Due to these limitations, software engineers that develop mobile applications must find ways to adequate them to the available. In this paper, we describe a strategy to safely manage memory traffic for mobile applications that intensively use bitmap font files, such as a document viewer.","Title: Model-Driven Development in the Production of Customizable Learning Objects\nYear: 2010\n\nAbstract: Learning Objects (LO) are digital resources developed to help teachers present the pedagogical concepts to students. However, the way these resources are produced does not allow teachers to adapt them to the reality of their students. Thus, this paper proposes a development process of customizable learning objects using a strategy based on models. Based on this approach, teachers will make adjustments to the LO and thus achieve more autonomy in the use of these resources.","Title: Safe adaptation in context-aware feature models\nYear: 2012\n\nAbstract: Software product lines, usually described using feature models, have proven to be a feasible solution to develop mobile and context-aware applications. These applications use context information to provide services and data for their users from anywhere and at any time. However, building feature models for mobile and context-aware software product lines demands advanced skills of software engineers, since it comprises system and context information. Moreover, to guarantee a correct application execution, these models must be thoroughly specified, composed and verified to check whether some composition and adaptation rules are violated. Although this is an important task, there is a lack of formalization of such rules, which makes it difficult to use those rules for feature models verification. In this paper, we propose an approach to prevent defects in context-aware feature models and in their product reconfiguration based on formal methods. To validate our work, we developed a prototype to check the correctness of context-aware feature models.","Title: LOCCAM - loosely coupled context acquisition middleware\nYear: 2013\n\nAbstract: Sensors of all kinds are being integrated with mobile and portable devices (tablets, smartphones). This opens up the possibility of context-aware applications to effectively be able to adapt their behavior, user interfaces and content according to the current user's situation. Frequently, context-aware applications require an infrastructure for acquisition, aggregation and reasoning of contextual information. However, existing context management infrastructures are not always appropriated to the heterogeneous and particular environment of mobile devices. In this paper, we present a context management middleware called LoCCAM (Loosely Coupled Context Acquisition Middeware) to provide self-adaptive acquisition of contextual information. It can execute both locally, on a single device, or distributed among nearby devices. The middleware proposes a model for publication, and notification of contextual information based on tuple spaces. As consequence, it offers a lower coupling among applications and the context acquisition layer. In this paper, we also present a performance evaluation of the adaptation mechanism.","Title: Impact of Density, Load, and Mobility on the Performance of Routing Protocols in Vehicular Networks\nYear: 2012\n\nAbstract: Designing routing protocols in vehicular network is a challenging task due to the high mobility of nodes, the instability of wireless links, and the diversity of deployment scenarios. Several routing protocols have been designed with the goal of solving one or more specific problems of each scenario. In this paper, we present a performance evaluation of routing protocols in vehicular networks addressing the impact of density, load, and mobility pattern. Four protocols are evaluated in urban and highway scenarios. The results presented in this paper provide guidelines for network designers in planning efficient routing protocols for vehicular network, able to adapt to different scenarios.","Title: Integration of routing and time synchronization protocols for wireless sensor networks\nYear: 2008\n\nAbstract: When dealing with Wireless Sensor Networks (WSN) applications that demand a high level cooperation of the sensor nodes, time synchronization is necessary to provide the correctness required for their results. In this work, we show that common issues between routing and time synchronization processes make their integration possible and, thus, can solve the problems of the resources consumption and time spent to acquire the synchronization. Two proposals for integrating them are presented.","Title: An approach for semantic enrichment of software product lines\nYear: 2012\n\nAbstract: Software Product Lines (SPLs) have evolved and gained attention as one of the most promising approaches for software reuse. Feature models are the main technique to represent domain variability in SPLs. However, there are other domain aspects, besides variability, which cannot be expressed in a feature model. Also, these diagrams were not designed to facilitate information retrieval, interoperability and inference. In contrast, ontologies seem to be the best solution to meet these requirements. Therefore, this work presents an approach for semantic enrichment of SPLs using ontologies. Our proposal provides methods to add domain information besides variability description, and a top-ontology that specifies generic concepts and relations in an SPL, working as a guide model for information addition. The proposed approach reuses the existing SPL feature model, adding semantic descriptions in a less intrusive way than modifying the feature model notation.","Title: RefaX: A Refactoring Framework Based on XML\nYear: 2004\n\nAbstract: Refactoring, i.e., the process of changing a software system to improve its internal quality and preserving its external behavior, is gaining increasing acceptance among software developers. Even though many refactoring tools are now available for a variety of programming languages, most of them are difficult to reuse, extend or even customize, mainly because they provide no uniform way of representing and manipulating source code information. This paper presents a refactoring framework, called RefaX, which relies on open, XML-based source code models and processing standards to facilitate the development, customization and reuse of refactoring tools. In particular, RefaX makes it possible to develop refactoring tools that are independent of source code model, programming language and XML processing technology. The viability of the framework is illustrated through a refactoring prototype for Java.","Title: MobiS: A Solution for the Development of Secure Applications for Mobile Devices\nYear: 2004\n\nAbstract: With the mobile computing evolution, portable devices have emerged in the market with the possibility of connection to IP\n networks using wireless technologies. The migration from fixed terminals to wireless mobile devices and the increasing availability\n of information for such devices impose new challenges in the development of applications. The security and the portability\n are examples of these challenges that constitute the motivation for this work. Our main goal is to introduce a solution, called\n MobiS (Mobility and Security), to the development of secure applications for data transmission using wireless technologies.","Title: A framework for text visualization using memory traffic management for mobile devices\nYear: 2009\n\nAbstract: Graphical User Interfaces (GUIs) of document viewers have gained attention with the increase on the number of mobile applications that uses it. However, mobile devices are still limited in relation to the available functionalities for text exhibition. Other limitations of these devices are the memory size, processing capacity and battery. This paper describes a framework for text visualization that safely manages memory traffic for mobile applications that intensively use bitmap font files, such as a document viewer. The main goal is to diversify the functionalities concerning to text exhibition in mobile devices, but also minimizing memory traffic.","Title: Ubiquitous Software Engineering: Achievements, Challenges and Beyond\nYear: 2011\n\nAbstract: Ubiquitous systems, or simply put Ubiquitous Sofware, are user-centric complex systems that must simultaneously deal with requirements such as mobility, portability, adaptability, interoperability and context-awareness, among others. In that direction, the last decades presented several Software Engineering techniques like frameworks and middlewares, component models, service-oriented architectures and software product lines, all trying to address and diminish the complexity to develop Ubiquitous Software. However, issues regarding the systematic development and proliferation of such software still lay untouched. Thus, it is mandatory to consider them, as well as to come up with production and commercialization models, in order to make the popularization of Ubiquitous Software plausible. Discussing these issues, this paper presents a summary of achievements on the development of Ubiquitous Software in the last decades, challenges ahead and future directions.","Title: Industry is From Mars, Academia is from Venus\nYear: 2011\n\nAbstract: In the last decades, the software industry and the Brazilian academia have been working more closely, mainly due to the incentives from funding agencies, such as CNPq, CAPES and FINEP, as well as tax incentives, like Brazil's Law of Informatics. As in any relationship, each party brings its own experiences, goals, targets and outcomes. Thus, for a partnership to be successful, it is important that each side learns how to deal with the differences, respecting the limits of each party, fostering mutual growth. In this context, the aim of this paper is to present the challenges faced by the GREat research group of the Federal University of Cear谩 over the past 10 years of industry partnership.","Title: FrameIDTV: A framework for developing interactive applications on digital television environments\nYear: 2010\n\nAbstract: Digital TV technologies are stretching out the horizons for interactive applications to end users. However, developing interactive applications for this new environment is not as straightforward as developing Internet applications. In order to make this development process easier in the context of interactive digital TV (iDTV), one of the solutions is the development of Frameworks. However, after investigating some of the existing iDTV framework solutions, we have found a limitation on the range of the interactive application domain to DTV available in these current frameworks, which mainly show solutions for local interactive (enhanced TV). Thus, in this paper, we propose an iDTV Framework (called FrameIDTV) that makes possible a broader solution in the DTV domain for the construction of interactive applications, both local and remote. The remote interactivity is possible using a generic and easy to customize communication protocol that is specified in the framework for the application layer. Furthermore, applications such as voting, home banking, and t-commerce, which are executed locally in the set-top box and are integrated to remote services using a return channel, can use the proposed framework. FrameIDTV also allows the establishment of secure communications and is developed following a specific framework methodology. This framework has primarily targeted the Brazilian Digital TV standard and its procedural middleware, called Ginga-J. Nevertheless, FrameIDTV can be broadly used worldwide, since it is compliant with the Globally Executable MHP (GEM) standard.","Title: An adaptive context acquisition framework to support mobile spatial and context-aware applications\nYear: 2013\n\nAbstract: The increasing number of mobile devices allows users to access applications anytime and anywhere. In such applications, location is a key information to improve the interaction between user and services. Existing applications combine location with other context information, such as weather, user's activity, temperature, among others. However, developing context-aware applications is still a non-trivial task due to the complexity to implement context management. Additionally, existing context management infrastructures are too brittle to handle changes in the underlying execution infrastructure. In this scenario, this work proposes a context acquisition framework, which tries to reduce the development complexity of mobile spatial and context-aware applications. The framework uses tuples space and OSGi to promote uncoupling and to adapt itself according to application requirements. A proof of concept was developed in order to show how spatial and context filters can be easily implemented during the development of a tracking application.","Title: RepliX: Um Mecanismo para a Replicação de Dados XML\nYear: 2007\n\nAbstract: XML has become a widely used standard for data exchange in ap- plications. Native XML DBMS are being developed to manage this data type. Such systems implement several characteristics that are common to traditional database systems. However, few of them provide replication mechanisms. The group communication abstraction is an efficient technology for implementing re- plication protocols since it provides reliability guarantees. This paper presents RepliX, a mechanism for XML data replication based on group communication. In order to evaluate RepliX, experiments measuring performance and availabi- lity were conducted.","Title: FramePersist: An Object Persistence Framework for Mobile Device Applications\nYear: 2004\n\nAbstract: Traditional requirements for persistence layers do not consider limitations of the development platforms available for mobile devices. In order to facilitate the development of applications, which need to store data, for mobile devices, these traditional requirements are reevaluated in this paper and a framework for object persistence is proposed. This framework, called FramePersist, is constructed based on the concept of object serialization and allows to persist and to search objects efficiently. Mapping rules of objects for persistence are presented together with a case study using the Symbian OS native file systems.","Title: Considerations on developing mobile applications based on the Capuchin project\nYear: 2010\n\nAbstract: The development of applications for mobile devices is becoming increasingly popular, with manufacturers struggling to support different programming environments and embedding libraries on their devices. In this pursuit for a straight-forward development of mobile applications, Java Micro Edition (JME) is a natural solution. Although JME has innumerous benefits, it offers limited support for user interface (UI) development. On a different path, Adobe's Flash Lite is tailored to develop rich UI for mobile applications. To bring together the advantages of both JME and Flash Lite, Sony Ericsson's Capuchin project permits the creation of interactive mobile applications, using Flash Lite to implement the user interface and JME to implement application core. The use of Flash Lite and JME in a single application has rised design issues that must be dealt by software engineers, such as performance, maintainability and reusability of both Flash Lite and JME programming languages. To guide software engineers design mobile applications, this paper presents a development process for interactive mobile applications based on Capuchin project. To validate it, a mobile application is developed based on this process, and relevant topics of the process are discussed.","Title: Framework for building intelligent mobile social applications\nYear: 2012\n\nAbstract: The use of online social networks (OSN) has been a reality for some years now. If OSN users have mobile devices and they are taken into account, every day a vast amount of information is spontaneously generated, creating opportunities for researchers and developers to use, for example, artificial intelligent techniques to explore similarities between friends, to recommend content and to come up with business opportunities. Additionally, OSN and mobile devices can be put together to explore user context to tailor services according to the user environment. However, to apply ubiquitous computing and artificial intelligence to OSN can be cumbersome and resource-consuming. Thus, this paper presents a framework to develop intelligent applications on top of existing OSN, helping developers to explore similarities between the users and recommend content, using user context and simple information present on OSN, without compromising resources present in mobile devices. At the end, this paper shows how to develop new applications using the framework exploring user context and semantic concepts defined by the developer.","Title: Improving network management with mobile agents in peer-to-peer networks\nYear: 2008\n\nAbstract: Regarding the size and the complexity growth of today's networks, several network management models have been studied and proposed. Furthermore, new requirements emerge with the interaction among entities that compose the management system, such as interoperability, collaboration among managers geographically separated, resources sharing, load balancing and inter-domain manager. It occurs that many of these models don't worry about the network logical configuration. In this paper, we present an improvement in the network management by combining P2P-Based Management System and Mobile Agents. The idea is to provide a mobile agent system extension for its integration with an architecture of network management based on Peer-to-Peer (P2P) networks. The mobile agent system makes it possible to have a more robust and self-organized network, together with the distributed system benefits.","Title: An Aspect-Oriented Programming Model for Bag-of-Tasks Grid Applications\nYear: 2007\n\nAbstract: This paper presents a novel programming model for explicitly separating parallelization and middleware-specific concerns in bag-of-tasks (BoT) grid applications. The model uses Java threads for application decomposition, and aspect-oriented programming to dynamically (and transparently) convert the application's thread objects into independent grid tasks, using the services of a specific grid middleware API. This paper also describes early experimental results showing the model's modularity gains and performance overhead, when applied to implement BoT grid applications using OurGrid.","Title: Requirements and challenges for building service-oriented pervasive middleware\nYear: 2009\n\nAbstract: The dinamicy and uncertainness of resources in mobile networks ask for novel uncoupled, adaptable and autonomous programming abstractions. Although applications are built upon a middleware layer that encapsulates some of that complexity, there is a lot left to fully explore the potential of ubiquitous and pervasive systems. To provide an insight on the challenges to develop interoperable middleware systems, this paper highlights the requirements to build service-oriented ubiquitous and pervasive middleware. These requirements are divided into primary and cross-cutting requirements. Primary requirements are Message Exchange, Mobility Support, Service Description, Discovery and Coordination, and Security. While Cross-cutting requirements are Context-Awareness and Adaptability, Autonomy, and QoS Requirements.","Title: Testing Requirements For Mobile Applications\nYear: 2009\n\nAbstract: Wireless networks have contributed to the technological advance that popularized the use of mobile devices, and fostered the development of applications targeted to these devices. However, issues such as mobility and communication intermittency, as well as processing, storage and battery constraints demand changes in the traditional software testing process. This paper aims to present testing requirements that are specific to applications developed for mobile devices. We also show that these requirements can improve productivity and efficacy in the testing process of an application.","Title: RETENTION: A reactive trust-based mechanism to detect and punish malicious nodes in ad hoc grid environments\nYear: 2013\n\nAbstract: In ad hoc grid environments, resources are not always available since nodes can spontaneously connect and disconnect at any time. Thus, these environments demand the correct execution of tasks to guarantee good performance. However, there are malicious users that affect the normal operation of these grids. These users modify tasks results and even cheat security mechanisms. Therefore, to assure high performance in these grid computing scenarios, it is essential to use punishment procedures based on trust models. These solutions have been used in wireless ad hoc networks, but not in the context of ad hoc grid computing. Thus, in this paper, we first present an analysis of mathematical trust models in ad hoc grid scenarios, using different ways to treat detection information passed on by other nodes. Then, we provide a comparison and a performance evaluation of these models using a grid simulator platform. Besides that, we choose the most accurate trust model among the evaluated ones to propose RETENTION: a reactive trust-based mechanism to detect and punish malicious nodes in ad hoc grid environments. Simulation results demonstrate the effectiveness of the proposed approach in detecting and punishing up to 100% of malicious nodes without generating false-positives. The results can be a valuable tool for network designers in planning trust models in ad hoc grid network deployments.","Title: Applying Artificial Neural Networks for Fault Prediction in Optical Network Links\nYear: 2004\n\nAbstract: The IP+GMPLS over DWDM model has been considered a trend for the evolution of optical networks. However, a challenge that has been investigated in this model is how to achieve fast rerouting in case of DWDM failure. Artificial Neural Networks (ANNs) can be used to generate proactive intelligent agents, which are able to detect failure trends in optical network links early and to approximate optical link protection mode from 1:n to 1+1. The main goal of this paper is to present an environment called RENATA2 and its process on how to develop ANNs that can give to the intelligent agents a proactive behavior able to predict failure in optical links.","Title: SLeSS: A Scrum and Lean Six Sigma Integration Approach for the Development of Sofware Customization for Mobile Phones\nYear: 2011\n\nAbstract: The development of embedded software for mobile phones requires a thorough knowledge of development processes, technologies and constraints related to software and hardware. Moreover, the growing competitiveness of this niche demands high productivity and quality. In this way, there is a need to invest in continuous improvement of processes, research for new technologies and methodologies, and increasing project performance to meet client needs and expectations. This paper proposes SLeSS, an integration approach of Scrum and Lean Six Sigma used in real projects of developing embedded software customizations for mobile phones. This approach enables the achievement of performance and quality targets, progressively improving the development process and the outcome of projects.","Title: GeoSPIN: An Approach for Geocast Routing Based on SPatial INformation in VANETs\nYear: 2013\n\nAbstract: Vehicular Ad hoc NETworks (VANETs) have been widely used to provide data exchange services in Intelligent Transport Systems (ITS), which should facilitate user's routines. At the same time that user's routines are improved, they can also be used as an important source of data for helping the decision-making process of VANET services. These routines can be acquired from vehicle's trajectories through the use of Global Positioning Systems (GPS). In this context, the combination of location-based data and data forwarding methods brings interesting challenges since these topics are not directly related. Therefore, the key idea of this work is to provide a geocast routing mechanism in VANETs based on daily movements of users in their vehicles. The main contribution is related to the delivery rate, which increases in partitioned and sparsely connected networks. The results show the efficiency of our new method to perform opportunistic routing based on location data, which discovers the best routes to forward packets through the network.","Title: Improving photo recommendation with context awareness\nYear: 2012\n\nAbstract: One of the most important challenges in Information Systems is information overload. Recommender Systems try to cope with this problem by helping people in retrieving information (ex: videos, services, products, images, etc.) that may match their preferences and intentions. An issue of Recommender Systems is related to user's context. The use of the system in a different context than usual may cause an unsatisfactory result for the recommendation, since preferences and intentions can be influenced by user's context (location, trajectory, time of day, activity, etc.). This paper presents the MMedia2U, a mobile photo recommender system that exploits the user's context and the context when photo was created as a means to improve the recommendation. Three context dimensions area exploited: spatial, social and temporal. We describe the similarity measures used for each dimension and the results of the system evaluation with 13 users following a Gold Standard approach.","Title: A Decoupled and Interoperable Architecture for Coordination in Ubiquitous Systems\nYear: 2011\n\nAbstract: Com o avanço das tecnologias de hardware, como o surgimento de computadores menores com maior poder de processamento e armazenamento, e o progresso da comunicação de dados sem fio, a Computação Ubíqua se tornou uma realidade. Entretanto, o desenvolvimento de sistemas ubíquos ainda apresenta inúmeros desafios devido à grande diversidade e complexidade dos seus requisitos. Particularmente, em ambientes ubíquos onde a dinamicidade e a heterogeneidade de dispositivos e serviços são características comuns, a coordenação desacoplada e interoperável das atividades realizadas entre os agentes de software do sistema torna-se essencial. Assim, esse trabalho propõe uma arquitetura que proporciona meios de interação e coordenação desacoplados e interoperáveis para o desenvolvimento de sistemas ubíquos.","Title: A Method for Model Checking Context-Aware Exception Handling\nYear: 2013\n\nAbstract: The context-aware exception handling (CAEH) is an error recovery technique employed to improve the ubiquitous software robustness. In the design of CAEH, context conditions are specified to characterize abnormal situations and used to select the proper handlers. The erroneous specification of such conditions represents a critical design fault that can lead the CAEH mechanism to behave erroneously or improperly at runtime (e.g., abnormal situations may not be recognized and the system's reaction may deviate from what is expected). Thus, in order to improve the CAEH reliability this kind of design faults must be rigorously identified and eliminated from the design in the early stages of development. However, despite the existence of formal approaches to verify context-aware ubiquitous systems, such approaches lack specific support to verify the CAEH behavior. This work proposes a method for model checking CAEH. This method provides a set of modeling abstractions and 3 (three) properties formally defined that can be used to identify exiting design faults in the CAEH design. In order to assess the method feasibility: (i) a support tool was developed, and (ii) fault scenarios that are recurring in the CAEH was injected in a correct model and verified using the proposed approach.","Title: MobiLine: A Nested Software Product Line for the domain of mobile and context-aware applications\nYear: 2013\n\nAbstract: Mobile devices are multipurpose and multi-sensor equipments supporting applications able to adapt their behavior according to changes in the user's context (device, location, time, etc.). Meanwhile, the development of mobile and context-aware software is not a simple task, mostly due to the peculiar characteristics of these devices. Although several solutions have been proposed to facilitate their development, reuse is not systematically used throughout the software development life-cycle. In this paper, we discuss an approach for the development of mobile and context-aware software using the Software Product Line (SPL) paradigm. Furthermore, a Nested SPL for the domain of mobile and context-aware applications is presented, lessons learned in the SPL development are discussed and a product for a context-aware visit guide is shown.","Title: An adaptation of the collections framework, reflection and object cloning from J2SE to J2ME\nYear: 2008\n\nAbstract: The jargon used by Sun Microsystems related to the Java technology \"write once, run anywhere\" does not match the reality when it comes to devices with distinct memory and processing capability as can be evidenced by software engineers in migration projects between J2SE and J2ME platforms. This work proposes a solution on how to port conventional desktop-tailored codes to less capable mobile devices, achieving the same results, with comparative examples that use the Collections framework classes, and the object cloning and reflection resources. Moreover, this paper shows a case study where the proposed process is applied.","Title: P2PScheMe: a P2P scheduling mechanism for workflows in grid computing\nYear: 2012\n\nAbstract: Complex scientific experiments have a growing demand for computational resources, which are expensive to be acquired and maintained. Grid computing has emerged as the mainstream technology to solve this issue. Grids are also adequate for the execution of scientific workflows because they allow the use of heterogeneous and distributed resources. In spite of the progress in grid technology, there are challenges to overcome in workflow scheduling. For instance, centralized scheduling solutions may lead to performance degradation and to problems with scalability. Some scheduling approaches are partially distributed, keeping a few centralized components that may become bottlenecks. Other distributed solutions have a lack of flexibility in the definition of workflows, in which only the use of tasks as steps in the workflow is permitted not high level services. In this work, we present P2PScheMe, a scheduling mechanism for peer-to-peer execution of workflows based on the invocation of grid services. The proposal considers information regarding grid execution environment in order to allow workflow scheduling adaptation. This adaptation is performed according to user requirements of quality of service. In this paper, we describe how P2PScheMe works and provides a comparative analysis with existing solutions. Copyright © 2011 John Wiley & Sons, Ltd.","Title: An Architecture Proposal for Nested Software Product Lines in the Domain of Mobile and Context-Aware Applications\nYear: 2010\n\nAbstract: The domain of mobile and context-aware applications involves challenging requirements, such as mobility and adaptation, which makes the application development complex for this area. Considering this scenario, we used a nested software product line (SPL) that aims to facilitate the construction of such software by domain decomposition in two levels of analysis. The first concerns the characteristics of a generic SPL for the mobile and context-aware domain. The second is the requirement analysis of a business domain together with characteristics of the generic level. The goal of this paper is to propose a nested SPL.","Title: Mobile Photo Recommendation and Logbook Generation Using Context-Tagged Images\nYear: 2014\n\nAbstract: Context-aware and semantic-based technologies have been successfully employed to improve multimedia management in mobile environments. Large sets of context-tagged images on the Web are a concrete example of this achievement. The authors present two mobile systems, MMedia2U and CAPTAIN, that take the concept of context-aware multimedia management beyond photo organization and annotation. CAPTAIN is a tool that helps generate logbooks using context-tagged images and tracking data. Crewmembers used this tool to manage multimedia content and publish it to a blog during a sea expedition. MMedia2U is a mobile photo recommender system that exploits the user's context and context-tagged images to improve photo recommendation.","Title: XMobile: A MB-UID environment for semi-automatic generation of adaptive applications for mobile devices\nYear: 2008\n\nAbstract: Ubiquitous Computing promises seamless access to information anytime, anywhere with different and heterogeneous devices. This kind of environment imposes new challenges to software development. For example, information and user interface should be adapted according to contextual characteristics such as user, environment, and access device. In case of device adaptation, the development challenge is related to the heterogeneity of the devices, which requires software engineers to create different versions for each type of device and every platform. This paper proposes a MB-UID (model-based user interface development) approach for semi-automatic generation of adaptive applications for mobile devices. An environment, called XMobile, offers a device-independent user interface framework and a code generation tool for providing fast development of multi-platform and adaptive applications according to device and platform features. A case study is also presented to illustrate how the environment can be used for constructing an application for heterogeneous devices with different network connectivity modes.","Title: Regularized Supervised Distance Preserving Projections for Short-Text Classification\nYear: 2014\n\nAbstract: Short-text classification is a challenging natural language processing problem. Beyond classification accuracy, another issue refers to the dimensionality of the feature vectors used for classification. This is especially important for embedded applications with hard constraints of computational power and memory. To deal with such problems, many techniques of dimensionality reduction have been developed over the last years. The Supervised Distance Preserving Projections (SDPP) has shown promising results. This work proposes a modified version of the SDPP method, called Regularized SDPP, which relies on the regularization theory. On the basis of experimental evaluation, the proposed approach has achieved good results in comparison to the state-of-the-art methods in nonlinear dimensionality reduction.","Title: Performance issues with routing in multi-channel multi-interface IEEE 802.11s networks\nYear: 2014\n\nAbstract: Wireless Mesh Networks have the potential to serve as an all-wireless backbone. They represent a key building block of the new Internet of Things to collect all the traffic. However, IEEE 802.11 performs very poorly in multi-hop topologies leading to unfairness and a poor throughput. Thus, the standard IEEE 802.11s proposes to re-use the IEEE 802.11 medium access in a mesh multi-hop topology while using a routing protocol to create routes at the layer 2. IEEE 802.11s may exploit multi-channel multi-interface wireless routers to increase the through-put. In particular, the routing protocol must select carefully the forwarders to limit inter- and intra-flow interference. In this paper, we propose to fully characterize the performance of IEEE 802.11s when using multi-interface nodes, and to isolate some key performance issues. We also propose some key mechanisms that must be implemented to solve these pathological cases and to improve the throughput.","Title: USABle -- A Communication Framework for Ubiquitous Systems\nYear: 2014\n\nAbstract: The widespread use of mobile devices is reshaping the way users interact, allowing applications to explore physical proximity of devices to offer intelligent services. Although there are several communication technologies available (e.g., Wi- Fi, Wi-Fi Direct, LTE, UMTS, Bluetooth, NFC), building an application from scratch considering both communication and application requirements is not a trivial task. In order to help developers to implement communication primitives, this paper presents a communication framework for ubiquitous systems called USABle. Two important contributions of this framework can be highlighted: i) a set of technology-independent interfaces to handle communication requirements; and ii) a modular and extensible layer-based architecture that permits developers to implement new communication technologies and message dissemination strategies. The outcome of using this communication framework is a simpler way to build applications that explore physical proximity. To validate the claims presented in this paper, a performance evaluation using real devices is done, analyzing two multi-hop and three carry-and-forward implementations of routing algorithms that were implemented using the USABle framework.","Title: How to Describe SPL Variabilities in Textual Use Cases: A Systematic Mapping Study\nYear: 2014\n\nAbstract: In the Software Product Line (SPL) paradigm, the variability description is an important issue for the requirements engineering process. In this scenario, there are several approaches in the literature focusing on how to describe variability in use cases. However, to the best of our knowledge, no efforts have been made to collect and summarize the existing templates for textual use case description in the SPL paradigm. This paper addresses this gap, presenting a systematic mapping study about SPL variability description in textual use cases. We found with this mapping, nine use case templates and four different ways to describe SPL variabilities in a use case description. From these templates, only one deal with the five variability types identified and we did not find any experimental study comparing these templates in terms of ease of use or comprehensibility.","Title: EPMOSt: an energy-efficient passive monitoring system for wireless sensor networks.\nYear: 2014\n\nAbstract: Monitoring systems are important for debugging and analyzing Wireless Sensor Networks (WSN). In passive monitoring, a monitoring network needs to be deployed in addition to the network to be monitored, named the target network. The monitoring network captures and analyzes packets transmitted by the target network. An energy-efficient passive monitoring system is necessary when we need to monitor a WSN in a real scenario because the lifetime of the monitoring network is extended and, consequently, the target network benefits from the monitoring for a longer time. In this work, we have identified, analyzed and compared the main passive monitoring systems proposed for WSN. During our research, we did not identify any passive monitoring system for WSN that aims to reduce the energy consumption of the monitoring network. Therefore, we propose an Energy-efficient Passive MOnitoring SysTem for WSN named EPMOSt that provides monitoring information using a Simple Network Management Protocol (SNMP) agent. Thus, any management tool that supports the SNMP protocol can be integrated with this monitoring system. Experiments with real sensors were performed in several scenarios. The results obtained show the energy efficiency of the proposed monitoring system and the viability of using it to monitor WSN in real scenarios.","Title: Templates for textual use cases of software product lines: results from a systematic mapping study and a controlled experiment\nYear: 2015\n\nAbstract: Use case templates can be used to describe functional requirements of a Software Product Line. However, to the best of our knowledge, no efforts have been made to collect and summarize these existing templates and no empirical evaluation of the use cases’ comprehensibility provided by these templates has been addressed yet. The contributions of this paper are twofold. First, we present a systematic mapping study about the SPL variability description using textual use cases. From this mapping, we found twelve SPL use case templates and observed the need not only for the application of these templates in real SPL but also for supporting tools. Secondly, this work presents an evaluation of the comprehensibility of SPL use cases specified in these templates through a controlled experiment with 48 volunteers. The results of this experiment show that the specification of variabilities in the steps’ numeric identifiers of the textual use cases is better to the use case understanding than the other approaches identified. We also found evidence that the specification of variabilities at the end of the use cases favors the comprehension of them and the use of questions associated to the variation points in the use cases improves the understanding of use cases. We conclude that each characteristic of the existing templates has an impact on the SPL use case understanding and this should be taken into account when choosing one.","Title: A pattern language for agile software estimation\nYear: 2012\n\nAbstract: This paper presents a pattern language for agile software estimation. The proposed language is composed of eight patterns and their relationships, which were identified through an extensive literature research and interviews with several companies that use agile methodologies. The patterns identified can help agile teams to obtain the main estimates needed in the context of agile software projects.","Title: Conflict of requirements: a pattern for the treatment of conflicting non-functional requirements\nYear: 2012\n\nAbstract: Software development is an activity that works several aspects of Software Engineering. One of them is requirements elicitation and its writing in an understandable notation for software developers. Non-Functional Requirements are those associated to the qualitative aspects of software such as performance, safety and usability. Normally the identification of non-functional requirements is conducted on an adhoc basis, and developed later. In this paper, a pattern is proposed for the treatment (identification and selection) of conflicting non-functional requirements in the early stages of its development, to not harm the quality of the system and also to be more suitable to customer needs.","Title: MLM-rank: A Ranking Algorithm Based on the Minimal Learning Machine.\nYear: 2015\n\nAbstract: Ranking is an important task in information retrieval and has gained much attention in recent years. Among the most used strategies, machine learning has achieved important results. The current work proposes a new machine learning based ranking algorithm, the MLM-RANK. MLM-RANK is based on the recently proposed Minimal Learning Machine (MLM). MLM is a supervised learning method that requires the adjustment of a single hyper parameter. The proposed method was evaluated against Prank and ELM Rank, both state of the art point wise ranking methods. In these tests MLM-RANK achieved promising results.","Title: Towards a formal model to reason about context-aware exception handling\nYear: 2012\n\nAbstract: The context-awareness is a central aspect in the design of pervasive systems, characterizing their ability to adapt its structure and behavior. The context-aware exception handling (CAEH) is an existing approach employed to design exception handling in pervasive systems. In this approach, the context is used to define, detect, propagate, and handle exceptions. CAEH is a complex and error prone activity, needing designers' insights and domain expertise to identify and characterize contextual exceptions. However, despite the existence of formal methods to analyze the adaptive behavior of pervasive systems, such methods lack specific support to specify the CAEH behavior. In this paper, we propose a formal model to reason about the CAEH behavior. It comprises an extension of the Kripke Structure to model the context evolution of a pervasive system and a transformation function that derivates the CAEH control flow from that proposed structure.","Title: Analyzing the Feature Models Maintainability over their Evolution Process: An Exploratory Study.\nYear: 2016\n\nAbstract: The feature model is one of the most important artifact of a Software Product Line (SPL). It is built in the early stages of SPL development and describes the main features and relationships. The feature model evolves according to the evolution of the SPL. Thus, it is important to build maintainable feature models. In this scenario, measures have been proven useful in the maintainability evaluation of the feature models. This paper presents an exploratory study on the impact of feature models maintainability over the SPL evolution process. In order to support this analysis, we built a dataset containing a compiled set of 21 maintainability structural measures extracted from 16 feature models and respective versions. Although not conclusive, our findings indicate that the feature models maintainability tends to decrease as it evolves. We also identified the most common changes performed in a feature model during its evolution process.","Title: A service-oriented architecture for billing resources in IaaS cloud platforms\nYear: 2015\n\nAbstract: Cloud Computing is a recent paradigm where different IT resources, such as applications or hardware, are quickly provisioned to customers through a pay per use model. Many research studies have already been conducted concerning billing services for cloud computing, but they lack on flexibility to establish how resources are defined and monitored. In fact, current solutions seem also very dependent on specific cloud infrastructures. This paper proposes an architecture for billing cloud services decoupled from specific providers, named as aCCountS. This service is complemented by a Domain Specific Language that allows the specification of flexible pricing policies. Such policies aims at supporting cloud billing requirements collected from our literature survey, allowing pricing schemes that meet different customer profiles. Based on this architecture, a prototype has been implemented and tested to validate our proposal in two different cloud infrastructures. Experiments confirmed that (i) the architecture hasn't dependencies of specific IaaS provider and (ii) the charging procedures are done correctly.","Title: Adaptive Tracking Model in the Framework of Medical Nursing Home Using Infrared Sensors\nYear: 2015\n\nAbstract: On Internet of Things (IoT), everything can be accessed anytime, anywhere, and works without human intervention. In IoT everything collaborates to deliver services and applications to users, Ambient Assisted Living (AAL) being one of these applications. Some AAL smart homes uses infrared sensors to recognize some activities of daily living and to track people along the environment. Location tracking is vital in Ambient Assisted living and can be a useful information to improve AAL systems. A common problem in such systems is that each tracking model is based on a specific sensor's placing architecture. In order to assure that the system will work properly, the model has to be fitted by an expert. Modeling is usually costly and it relies on a specific architecture. In our previous work, the tracking model needed to be fitted manually. In order to introduce adaptability, this work proposes an approach to automatically fit the model avoiding the need of an expert to fit a different model for each kind of sensor's placing architecture. The proposed approach was evaluated using real data from a set of pyroelectric infrared sensors and a set of scenarios performed in a simulated apartment.","Title: Using the GQM Method to Evaluate Calmness in Ubiquitous Applications\nYear: 2015\n\nAbstract: Ubiquitous systems change the way users interact with computers, because their services must be available everywhere at any time, supporting users in various everyday activities. An essential element for these systems is their calm interaction with users, which means the system should not disturb them unnecessarily. Literature currently lacks work focusing on how to evaluate calmness and case studies made in a real usage situation. The aim of this work is to propose a model, defined using the Goal-Question-Metric GQM method, for calmness evaluation in ubiquitous systems and to show our results from a case study with three ubiquitous applications.","Title: Mobile phone text messaging to increase student participation: an experience in a blended course.\nYear: 2016\n\nAbstract: Mobile technology is a suitable tool to be used for learning purposes. Many research studies prove the benefits of Mobile Learning (m-learning) in various education disciplines. Following this trend, our study examined a post-graduate class consisting of 474 learners in which Short Message Service (SMS) was used. The main goal was to find out if this technology would increase student participation in the course. The lecture series were implemented by using a blended learning approach, in which the courses combine face-to-face classes with online activities. Two groups of learners were created, control and experimental, in order to analyze the activities' fulfillment rate and the response time. The results from the data analysis showed that students who received mobile messaging outperformed significantly students from the control group. The experimental group had better results both in completion rate and response time. They were almost 20% more effective at completing their assigned activity and up to 78 hours faster than students from the control group. In addition, a questionnaire answered by the experimental group demonstrated that participants were very satisfied with the usage of this technology and were enthusiastic about the use of messages on the course.","Title: Towards a component infrastructure for cyber-physical systems.\nYear: 2016\n\nAbstract: The proximity between physical and cyber worlds is permitting the appearance of Cyber-Physical Systems (CPS), formed by users and devices (physical) interacting with services, components and applications (cyber). In CPS, where unpredictability is an important challenge, two characteristics must be present in the developed systems: i) low coupling among interacting modules and ii) self-adaptive capabilities. In that direction, this paper describes an uncoupled sensor and actuator component-based infrastructure for self adaptive CPS. Its main contribution is two-fold: i) a lightweight and interoperable mechanism to specify and manage sensors and actuators, built on top of an ii) uncoupled communication and coordination mechanism for cyber-physical entities.","Title: Design and usability of a braille-based mobile audiogame environment.\nYear: 2016\n\nAbstract: The rise of digital technologies brought positive changes to the lives of people who are blind. However, they are gradually making Braille less attractive and diminishing its importance. In this context, we investigate whether mobile games can be useful to improve the Braille practice through language exercises, for students with visual disabilities. We present the Game Braille Environment (GBraille), a suite composed of audiogames and a mobile virtual keyboard based on the metaphor of Braille's 6-dots cells system. GBraille Keyboard provides a text-based mechanics to mobile games. GBraille audiogames offer Portuguese and Spanish language exercises. We implemented an initial evaluation study of GBraille audiogames and GBraille Keyboard including Brazilian students with visual disabilities and Chilean and Brazilian special education teachers. Preliminary results are promising and indicate a good level of acceptance by students who are blind, who were able to perform the evaluation tasks.","Title: Requirements Engineering and Variability Management in DSPLs Domain Engineering: A Systematic Literature Review.\nYear: 2016\n\nAbstract: Recently, Software Product Lines (SPLs) have been used successfully for building products families. However, the currently and complex software products demand more adaptive features. Today, many application domains demand capabilities for flexible adaptation and post-deployment reconfiguration. In this context, Dynamic Software Product Lines (DSPLs) represent a way to produce software products able to change their own behavior at runtime due to the changes in the product use environment. DSPLs present some interesting properties such dynamic variability and reconfiguration at runtime. The dynamic variability is represented by the definition of variants and context information. The reconfiguration at runtime is the process that enables the features activation and deactivation in a configuration product. Both properties are closely related to the requirements engineering and variability management, in the domain engineering life-cycle. In this research, we provide a systematic literature review that aims to identify the activities, assets, tools and approaches that are used in requirements engineering and variability management in DSPLs domain engineering. We performed a manual and automatic search, resulting in 581 papers of which 37 were selected. We also provide a discussion about the challenges and solutions of runtime variability mechanisms in the context of DSPLs.","Title: DyMMer: a measurement-based tool to support quality evaluation of DSPL feature models.\nYear: 2016\n\nAbstract: For Dynamic Software Product Lines (DSPLs), evaluating the quality of a feature model is important to ensure that errors in the early stages do not spread throughout the DSPL. Measures extracted from feature models have been proved to be useful in the quality evaluation of such models. However, the process used for computing the values of these quality measures for a large set of feature models can be cumbersome and error prone. To cope with this problem, we present DyMMer, a tool to support the automatic extraction of quality measures from feature models in DSPLs. After that, we can analyse the results and propose improvements for the feature models. Currently, the DyMMer tool is able to collect 40 different quality measures from a DSPL feature model.","Title: Model Verification of Dynamic Software Product Lines.\nYear: 2016\n\nAbstract: Dynamic Software Product Lines (DSPLs) extend the concept of Software Product Lines enabling adaptation at runtime according to context changes. Such dynamic behavior is typically designed using adaptation rules, context-triggered actions responsible for features activation and deactivation at runtime. The erroneous specification and the interleaving of adaptation rules (i.e., the parallel execution of adaptation rules) can lead DSPL to reach an undesired (improperly or defective) product configuration at runtime. Thus, in order to improve the reliability of DSPL behavior, design faults must be rigorously identified and eliminated in the early stages of DSPL development. In this paper, we address this issue introducing Dynamic Feature Transition Systems (DFTSs) that allow the modeling and formal verification of the DSPLs adaptive behavior. These transition systems are derived from the adaptation rules and a Context Kripke Structure, which is a context evolution model. Furthermore, we formally define five properties that can be used to identify existing design faults in DSPL design. Aiming to assess the feasibility of our approach, a feasibility study was conducted using two DSPLs, Mobile Visit Guides and Car. In both cases, design faults were automatically detected indicating that our formalism can help in the detection of design faults in the DSPLs adaptive behavior.","Title: Investigating the Mode in Multimodal Video Games: Usability Issues for Learners who are Blind.\nYear: 2017\n\nAbstract: This paper presents an ongoing work on methods for usability evaluation of audio- and haptic-based video games for learners who are blind. We report a Standard Usability Problem List which we envision to be the basis for comparison of the Usability Evaluation Methods (UEM) in this context. In addition, we present a preliminary analysis of evidence on what problems different UEMs can reveal by evaluating audio, interaction mode, interface adaptation, and feedback.","Title: Fifteen Years of Industry and Academia Partnership: Lessons Learned from a Brazilian Research Group.\nYear: 2017\n\nAbstract: In Brazil, software industry and academia have formed partnerships more often due to funding agencies and tax incentives originated, for example, from Brazil's Informatics Law. Like in many relationships, each party brings different experiences, and goals to be achieved. However, for a partnership to be successful, it is necessary to learn how to deal with these differences, respecting the limits of each party and fostering mutual growth. The aim of this paper is to present challenges and lessons learned faced by the GREat research group at the Federal University of Ceará over the past 15 years of partnership with industry. Besides, we present the GREat Business process for projects with industry and how the software engineering evolved in our group within these projects. We believe this report can help other industry and academic partnerships around the world not only because our main partners are international companies but also because what we have learned from practice is globally applied.","Title: Generating test cases and procedures from use cases in dynamic software product lines.\nYear: 2017\n\nAbstract: Software engineering is systematically evolving to address the production of families of systems instead of single products. This evolution comes at a price, it is now essential to deal with variability at both design and execution time. Developing test cases and procedures for a whole family of systems considering this dynamicity (variability at runtime) can be challenging. We propose a method to generate tests from use case specifications expressed in a controlled natural language, yet considering the variability and dynamicity in those specifications. We evaluate our method against use case specifications of a family of mobile and context-aware systems. Experimenting our method, we could measure that developing test cases and procedures becomes around 40+ faster when using our approach, opposed to manual development of tests under the same conditions.","Title: ReMINDER: An Approach to Modeling Non-Functional Properties in Dynamic Software Product Lines.\nYear: 2017\n\nAbstract: This paper presents a systematic approach to modeling NFPs in DSPL feature models. In our proposed approach, feature models are annotated with the representation of NFPs, rules for the activation and deactivation of features, constraints between NFPs and features, and context adaptation scenarios. To evaluate the applicability of the proposed approach we carried out an empirical evaluation. The approach yielded good results at identifying NFPs in DSPLs.","Title: DyMMer-NFP: Modeling Non-functional Properties and Multiple Context Adaptation Scenarios in Software Product Lines.\nYear: 2017\n\nAbstract: In Software Product Lines (SPLs), the modeling of nonfunctional properties (NFPs) and context adaptation scenarios are important activities, once they make possible the identification of interdependencies constraints between functional requirements (FR) and NFP, according to a specific adaptation context scenario. However, there are few tools to help domain engineers to represent NFPs and context adaptation scenarios. To deal with this problem, we propose DyMMerNFP, an extension of the DyMMer tool to support the modeling of NFPs and multiple contextual adaptation scenarios in feature models. DyMMer-NFP uses a catalog with 39 NFPs. Each NFP in this catalog were mapped according to each quality characteristic and subcharacteristics presented in the ISO/IEC 25010 SQuaRE product quality model. To specify the interdependencies between NFPs and features, DyMMer-NFP has used the concept of contribution links. In order to make it easier to evaluate DyMMer-NFP two datasets, called AFFOgaTO and ESPREssO, were made available for free.","Title: Evaluating An Iot Application Using Software Measures\nYear: 2017\n\nAbstract: Internet of Things (IoT) allows daily objects, with computing and communication capabilities, to connect to the Internet. In this scenario, an application called GREatRoom runs in an IoT environment, which has distributed wireless labels in places and objects, to detect the presence of nearby users, providing services intuitively and efficiently. Considering that IoT systems have quality characteristics of human-computer interaction similar to those of ubiquitous systems, this paper investigates the applicability of software measures from ubiquitous to IoT systems and presents the positive results achieved in this evaluation.","Title: When Technology Supports Urban Mobility: Improvements for Mobile Applications Based on a UX Evaluation.\nYear: 2017\n\nAbstract: The development of applications that helps urban mobility has been pushed by the increase of processing capacity and miniaturization of the mobile device as well as the improvement of speed and availability of Internet. Such applications can support users in several activities such as tracing routes and searching for addresses. In this scenario, this work aims to: (i) understand how users use urban mobility applications; (ii) evaluate the quality of interaction and interface into real applications called “Waze” and “Meu Onibus”; and (iii) improve the applications based on the results of the evaluations. Moreover, this study also suggests a set of recommendations for urban mobility applications in developing countries like Brazil.","Title: What Changes From Ubiquitous Computing To Internet Of Things In Interaction Evaluation?\nYear: 2017\n\nAbstract: Internet of Things (IoT) is a new paradigm that includes a network of smart objects, which are embedded sensors, communicating using the Internet. One of the areas that are leading up to IoT is Ubiquitous Computing (UbiComp). There are thus solutions such as frameworks, middlewares, and other development artifacts that come from the UbiComp community and can be used for IoT applications. On the other hand, the interaction evaluation of the applications can be more complex in IoT than in UbiComp systems, once we have two different perspectives: Human-Thing and Thing-Thing interactions. In this paper, based on the literature, our experience in these two domains, and case studies with Ubicomp and IoT applications, we discuss how we can benefit from the UbiComp move towards IoT, focusing on the main differences and similarities related to interaction evaluation. These differences open a set of questions that are also presented and discussed in this paper.","Title: Recommendations for Usability Testing in Ubiquitous Applications\nYear: 2016\n\nAbstract: Ubiquitous systems change the way users interact with computers, because their services must be available anytime and everywhere, supporting users in several everyday activities. Thus, there is a high risk of users feeling annoyed and overwhelmed by ubiquitous systems. It is, therefore, essential to evaluate the quality of use in those systems. One of the methods to perform this activity is the usability testing. However, the traditional process does not take into account specific characteristics from ubiquitous systems, for example context-awareness, transparency, attention, calmness, and mobility. This paper provides eight recommendations for usability testing in ubiquitous applications based on a literature review and on the authors experience with the evaluation of those systems.","Title: Preventing Erosion in Exception Handling Design Using Static-Architecture Conformance Checking.\nYear: 2017\n\nAbstract: Exception handling is a common error recovery technique employed to improve software robustness. However, studies have reported that exception handling is commonly neglected by developers and is the least understood and documented part of a software project. The lack of documentation and difficulty in understanding the exception handling design can lead developers to violate important design decisions, triggering an erosion process in the exception handling design. Architectural conformance checking provides means to control the architectural erosion by periodically checking if the actual architecture is consistent with the planned one. Nevertheless, available approaches do not provide a proper support for exception handling conformance checking. To fulfill this gap, we propose ArCatch: an architectural conformance checking solution to deal with the exception handling design erosion. ArCatch provides: (i) a declarative language for expressing design constraints regarding exception handling; and (ii) a design rule checker to automatically verify the exception handling conformance. To evaluate the usefulness and effectiveness of our approach, we conducted a case study, in which we evaluated an evolution scenario composed by 10 versions of an existing web-based Java system. Each version was checked against the same set of exception handling design rules. Based on the results and the feedback given by the system's architect, the ArCatch proved useful and effective in the identification of existing exception handling erosion problems and locating its causes in the source code.","Title: Aggregating Measures using Fuzzy Logic for Evaluating Feature Models.\nYear: 2018\n\nAbstract: In the context of Software Product Lines (SPLs), evaluating the quality of a feature model is essential to ensure that errors in the early stages do not spread throughout the SPL. One way to evaluate a feature model is to use measures. However, measures alone are not enough to characterize the feature model quality, because most of them cover specific aspects, such as the number of features. So, there is a need for methods to aggregate measures at the level of quality sub-characteristic or characteristic. In this paper, we aim to investigate how to aggregate measures that have been proposed to evaluate the quality of feature models in SPL. We have used the fuzzy logic theory in order to aggregate these measures. The new aggregated measures can be applied to evaluate different and complex aspects of a feature model, such as: size, stability, flexibility and dynamicity. Moreover, to evaluate the use of the new aggregate measures, we applied them in different feature models. Our findings suggest that aggregate measures can assist the domain engineer in evaluating the maintainability of feature models.","Title: Towards a catalog of conflicts for HCI quality characteristics in UbiComp and IoT applications: Process and first results.\nYear: 2018\n\nAbstract: Conflicts between non-functional requirements (NFRs) can happen when a particular solution favors the first NFR but creates difficulty for the second one. Usually, in the literature, the conflict identification uses catalogs to indicate conflicting NFRs. The authors focus on NFRs that are generic to any system. However, applications from Ubiquitous Computing (UbiComp) and Internet of Things (IoT) introduce new kind of NFRs (e.g., Context-Awareness and Mobility). They are not included in these catalogs and can impact the traditional ones (e.g., Security and Usability). Therefore, there is a need to create a catalog that considers conflicts among quality characteristics for UbiComp and IoT applications. However, the literature lacks a process or guideline about how to create a catalog. This paper aims then to present a process and initial findings towards a catalog of conflicts between specific HCI quality characteristics in UbiComp and IoT applications and Usability.","Title: Bio-Inspired Model for Data Distribution in Fog and Mist Computing.\nYear: 2018\n\nAbstract: Fog and Mist computing exploits computational resources of IoT devices located at the edge of the network. This new infrastructure brings benefits related to latency and Internet bandwidth utilization when compared with Cloud computing. However, this scenario is quite challenging mainly due to the considerable heterogeneity of the devices and to the dynamicity of the network topology what adds new issues related to security, privacy, data availability, and service availability, among others. Despite the theme of data dissemination and data storage had been relatively explored in fields of Sensor Wireless Network (WSN) and Vehicular Ad Hoc Networks (VANETs), we found few studies in the Fog computing research area. Then, this work focuses on the problem of data availability and dissemination in this environment by proposing a distributed algorithm using ideas from evolutionary computation and epidemic models. Results obtained through simulation suggest that the algorithm presents proper results in maintaining data availability in the Fog and Mist Computing environments, even under severe conditions.","Title: Cloning In Customization Classes: A Case Of A Worldwide Software Product Line\nYear: 2018\n\nAbstract: Cloning-and-owning, in the long run, can severely affect evolution, as changes in cloned fragments may require modifications in various parts of the system. This problem scales if cloning is used in classes that derive products in a Software Product Line, because these classes can impact in several features and products. However, it is hard to know to which extent cloning in customization classes can impact in a project. We conduct a study, within an SPL that generates mobile software for over 150 countries, to analyze cloning practices and how cloned parts relate to the maintainability of customization classes. We collect and identify clones inside customization classes during a period of 13 months, involving 70 customization classes and 5 branches. In parallel, we collect the respective issues from the issue tracking tool of the SPL project, obtaining over 140 issues related to customization classes. We then confront the time spent to solve each issue with its nature (i.e., if it relates to cloned code or not). As first result, we verify that issues related to cloning take in average 136% more time to be solved. Our study helps to understand how cloning relates to maintainability in the context of mass customization, giving insights about cloned code evolution and its impacts in a software product line project.","Title: Catalog of Invisibility Requirements for UbiComp and IoT Applications\nYear: 2018\n\nAbstract: A new set of Non-Functional Requirements (NFRs) have appeared with the advent of Ubiquitous Computing (UbiComp) and more recently Internet of Things (IoT). Invisibility is one of these NFRs that means the ability to hide technology from users. Although invisibility is long seen as an essential characteristic for achieving the goals of UbiComp, it has not been cataloged regarding its subcharacteristics and solutions, making its design and requirements specification in such applications a challenging task. Considering the Softgoal Interdependency Graph (SIG), which is a well-known format to catalog NFRs, this work aims at capturing subcharacteristics and solutions for Invisibility and cataloging them in a SIG. Since there is no systematic approach on how to build SIGs, we also propose to systematize the definition of Invisibility SIG using the following well-defined research methods: snowballing, database search, grounded theory and questionnaires. As a result, we got an Invisibility SIG composed of two main subcharacteristics, twelve sub-subcharacteristics, ten general solutions and fifty-six specific solutions. This organized body of knowledge is useful for supporting software engineers to specify requirements and practical solutions for UbiComp and IoT applications. Furthermore, the proposed methodology used to capture and catalog requirements in a SIG can be reused for other NFRs.","Title: Correlations between invisibility and usability in ubicomp and IoT applications: partial results.\nYear: 2018\n\nAbstract: Quality characteristics present several difficulties to be addressed. Negative correlations are one of these issues developers must deal during software development. These correlations mean that supporting a characteristic can negatively impact another one. A well-known solution to help developers identifying such correlations is through non-functional requirements (NFRs) catalogs. Although there are several correlations catalogs proposed in the literature, they do not take into account new characteristics that have arisen with the Ubiquitous Computing (UbiComp) and the Internet of Things (IoT) environment, such as Invisibility. In a previous study, a process for defining a catalog of correlations for quality characteristics was proposed. In this paper, we present partial results of the execution of this process for Invisibility and Usability. We also discuss some challenges regarding catalogs for quality characteristics.","Title: Exploring quality measures for the evaluation of feature models: a case study.\nYear: 2017\n\nAbstract: •We built a dataset that contains the values of 32 measures from COfFEE catalog.•We applied the Spearman’s rank to indicate the correlation between the 32 measures.•We grouped the measures by applying the PCA technique and defined 9 new measures.•We defined statistical thresholds for these 9 new grouped measures.","Title: Heuristics To Evaluate The Usability Of Ubiquitous Systems\nYear: 2017\n\nAbstract: While the ubiquitous systems have characteristics that modify the way the user interacts with the systems, Human-Computer Interaction area studies forms of interaction, with usability being one of the main quality criteria. One of the methods used to evaluate usability is Heuristic Evaluation. In the case of ubiquitous systems, that have characteristics such as mobility and context awareness, Nielsen's heuristics, which are widely used in conventional systems, do not focus on these particularities. Therefore, this work proposes specific heuristics to evaluate the usability of ubiquitous systems. Empirical studies and questionnaires were applied with experts in order to evaluate the proposed heuristics. The results point to improvements in both the way of conducting the evaluation and in the heuristics. From these results, the proposed heuristics were refined.","Title: Mobile Audio Games Accessibility Evaluation For Users Who Are Blind\nYear: 2017\n\nAbstract: Digital games have become increasingly popular for both entertainment and education purposes. However, making these games universal and accessible poses a challenge for interface designers and game developers, since they are usually unfamiliar with the peculiarities of gamers who are blind. More effort is necessary for contributing to a universal game design and, ultimately, helping to promote the inclusion of people with disabilities to take full advantages of digital games. In this research, we present a study concerning existent guidelines and recommendations for accessibility in digital games. As a result, we propose ten recommendations for the design of mobile audio games, targeting gamers who are blind. We also present an evaluation instrument assembled from the recommendations we propose. We used this instrument to assess ten audio games labeled as inclusive. Results indicate that only three from a total of ten games were considered \"good\", which means they met the fundamental aspects of the guidelines.","Title: Issue Auto-Assignment in Software Projects with Machine Learning Techniques\nYear: 2021\n\nAbstract: Usually, managers or technical leaders in software projects assign issues manually. This task may become more complex as more detailed is the issue description. This complexity can also make the process more prone to errors (misassignments) and time-consuming. In the literature, many studies aim to address this problem by using machine learning strategies. Although there is no specific solution th...","Title: IoT-Health Platform to Monitor and Improve Quality of Life in Smart Environments\nYear: 2021\n\nAbstract: Having a full and healthy life is what most people want. This involves a set of domains such as physical and psychological health, social relationships, and environmental issues. Together, these domains can be used to characterize a person's Quality of Life (QoL). This desire for a healthy life becomes even more prominent as the world population ages. Thereby, new socioeconomic challenges arise, putting pressure on governments and industries to adopt technologies to improve QoL. One of the technologies that have been widely used is the Internet of Health Things (IoHT). However, developers still face challenges when proposing IoHT solutions, such as lack of interoperability, high volatility, difficulties in providing runtime adaptations, high development cost when it involves AI, and the absence of a semantic model for QoL data. Thus, this Ph.D. project aims to investigate the development of QoL-based IoHT systems to address these challenges. As a result, an IoT-Health Platform is expected to support this development and bring health professionals closer to this process.","Title: D-CreEA: DSML for Creating Educational Analog Card Games\nYear: 2021\n\nAbstract: Educational games can promote a playful learning experience by solving problems related to the subject of a discipline and assign a student as the main actor in the learning process. In addition, when using analog educational games, this experience provides a face-to-face discussion on the subject, with tactile interaction and quick feedback. However, creating an educational game is difficult, bec...","Title: Not the Same Everywhere: Comparing the Scope and Definition of User Experience between the Brazilian and International Communities\nYear: 2022\n\nAbstract: The Human-Computer Interaction community worked over the last years on scoping and defining User Experience (UX). As reported in the literature, UX's understanding changes according to the socio-cultural context and between professional positions, making a global consensus unattainable. Nevertheless, tracking and investigating the most accepted UX definitions and statements may be advantageous for visualizing multiple contexts' needs. Such an investigation is still scarce and even more significant in developing countries since there are structural differences from developed countries in the software development industry that directly impact user research practices. To fill in this gap, we replicated in Brazil a survey distributed before, mostly among professionals from developed countries. We compared 252 responses from academics and practitioners and identified differences and similarities among Brazilian and international communities. The definitions of UX chosen by the academic and industrial domains explain differences in UX design and evaluation. When comparing Brazilians' responses with previous studies, Brazilians give greater importance to qualitative measures and to different UX time spans.","Title: Performance Testing Guide for IoT Applications\nYear: 2022\n\nAbstract: Internet of Things (IoT) applications are characterized by the use of smart objects that are connected to the Internet to provide different types of services. These objects usually generate data that need to be stored and analyzed to contribute to decision making (whether or not they are immediate). In this context, such applications may require high performance, low cost and good scalability. These requirements bring new testing challenges and the need for specific approaches, for example, the detection of performance failures among heterogeneous IoT devices, which process a large amount of data and, under uncertain conditions, must have their resources optimized. Thus, our goal is to propose a performance testing guide for the evaluation of IoT applications. To build the guide, we performed a literature review to identify the IoT standards and analyzed IoT bug repositories. In this paper, we present the Performance Testing Guide for IoT applications. To validate the proposed guide, we conducted two evaluations: (i) an evaluation with the experts; and (ii) a controlled experiment. The results showed that the guide provides a systematization of testing activities, helping the evaluation of IoT aspects intrinsic to performance.","Title: Where Is the Internet of Health Things Data?\nYear: 2022\n\nAbstract: The advent of Internet of Things (IoT) and the smart objects popularization have boosted the data generation in many areas. Data have then become increasingly valuable as they can be used to \"teach\" machines to perform the most varied tasks. Health is among the areas that have benefited from such data, because there is, for example, a need for solutions that optimize the cost-benefit ratio of health systems. In this scenario, the Internet of Health Things (IoHT) uses smart sensors to collect patient data and intelligent algorithms to process this data for improving patient Quality of Life. However, researchers and practitioners have faced difficulties in finding and using public health care data sensor repositories. Therefore, we conducted a systematic multivocal review of IoHT databases to identify and characterize the existing datasets. We also bring as a contribution of this paper a set of guidelines about how new IoHT data repositories can be structured."],"string":"[\n \"Title: PEARL: A PErformance evaluAtor of cRyptographic aLgorithms for Mobile Devices\\nYear: 2004\\n\\nAbstract: Limited computational power imposes new challenges during the implementation of security and privacy solutions for mobile devices. The choice for the most appropriate cryptographic algorithm for each mobile device has become a critical factor. In this paper, we present an approach for performance evaluation of cryptographic algorithms for mobile devices. A tool called PEARL (PErformance evaluAtor of cryptogRaphic aLgorithms for mobile devices) is also introduced in this work to validate the approach. This tool collects and analyzes information related to executions of the cryptographic algorithms in the mobile devices. Moreover, PEARL allows evaluating the performance of symmetrical and asymmetrical cryptographic algorithms, and hash functions for the J2ME platform.\",\n \"Title: A Verification Mechanism of Feature Models for Mobile and Context-Aware Software Product Lines\\nYear: 2011\\n\\nAbstract: Software Product Lines (SPLs) have been used to develop mobile and context-aware applications, which provide services and data for their users from anywhere and at any time using context information. In SPLs, commonality and variability of a system family are identified and often documented in a feature model. However, the development of a feature model for mobile and context-aware SPLs is not trivial, since it should comprise system and context information. Furthermore, the consistency check of feature models in the considered domain is also complex and demands advanced skills of software engineers. This paper proposes a mechanism to formalize and verify the correctness and consistency of feature models for mobile and context-aware SPLs based on a profile enriched with OCL specifications.\",\n \"Title: A Coordination Framework For Dynamic Adaptation In Ubiquitous Systems Based On Distributed Tuple Space\\nYear: 2013\\n\\nAbstract: The evolution of mobile technologies allows the emerging of ubiquitous systems, able to anticipate user needs and to seamlessly adapt to context changes. These systems present the problem of dynamic adaptation in a highly distributed, heterogeneous and volatile environment, since it may be difficult to collect and process context information from distributed unknown sources. In order to facilitate the development of such systems, this paper extends an existing coordination framework based on tuple spaces, aiming at the management of distributed information. Hence, a decentralized coordination framework was created, offering primitives to developers to create ubiquitous systems able to interact and cooperate in scenarios of total decentralization. This paper reports some experimental results obtained in a testbed of smartphones and tablets which demonstrate the practical feasibility of our approach and pointed out how our solution can grant context data dissemination in ad hoc and infrastructured networks.\",\n \"Title: FRAMESEC: A Framework for the Application Development with End-to-End Security Provision in the Mobile Computing Environment\\nYear: 2005\\n\\nAbstract: Mobile devices offer network connectivity through wireless system communication that makes possible for applications to get access to information at any time and any place. However, the wireless link is more vulnerable to pas- sive and active attacks than the fixed medium in the traditional networks. Then, this kind of connectivity brings security problems to the applications that deal with confidential data, such as mobile commerce. Although wireless communi- cation systems, such as IEEE 802.11, implement protection mechanisms for data transmission, they have reported vulnerabilities and do not guarantee end- to-end security, which is desirable for these applications. Thus, this work pro- poses an application framework that provides a reusable structure with security mechanisms, which enable end-to-end security in the mobile computing envi- ronment.\",\n \"Title: A software product line for the mobile and context-aware applications domain\\nYear: 2010\\n\\nAbstract: The mobile and context-aware application domain presents challenging requirements to software development. Although several solutions have been proposed for this type of application, reuse is not systematically used throughout the software development lifecycle. Then, in this paper we propose an approach for the development of a mobile and context-aware Software Product Line (SPL). A SPL for the mobile and context-ware mobile guide domain is presented in order to illustrate the steps of the proposed approach. Furthermore, the lessons learned in the SPL development are discussed. Both approach and SPL are the main contributions of this paper.\",\n \"Title: A strategy for memory traffic management of bitmap fonts for text visualization in mobile devices\\nYear: 2008\\n\\nAbstract: Document viewer and browser applications have gained attention in the mobile scenario due to the improvement on accessibility and portability of different kinds of information. However, mobile devices are still limited in relation to memory size, processing capacity and battery. Due to these limitations, software engineers that develop mobile applications must find ways to adequate them to the available. In this paper, we describe a strategy to safely manage memory traffic for mobile applications that intensively use bitmap font files, such as a document viewer.\",\n \"Title: Model-Driven Development in the Production of Customizable Learning Objects\\nYear: 2010\\n\\nAbstract: Learning Objects (LO) are digital resources developed to help teachers present the pedagogical concepts to students. However, the way these resources are produced does not allow teachers to adapt them to the reality of their students. Thus, this paper proposes a development process of customizable learning objects using a strategy based on models. Based on this approach, teachers will make adjustments to the LO and thus achieve more autonomy in the use of these resources.\",\n \"Title: Safe adaptation in context-aware feature models\\nYear: 2012\\n\\nAbstract: Software product lines, usually described using feature models, have proven to be a feasible solution to develop mobile and context-aware applications. These applications use context information to provide services and data for their users from anywhere and at any time. However, building feature models for mobile and context-aware software product lines demands advanced skills of software engineers, since it comprises system and context information. Moreover, to guarantee a correct application execution, these models must be thoroughly specified, composed and verified to check whether some composition and adaptation rules are violated. Although this is an important task, there is a lack of formalization of such rules, which makes it difficult to use those rules for feature models verification. In this paper, we propose an approach to prevent defects in context-aware feature models and in their product reconfiguration based on formal methods. To validate our work, we developed a prototype to check the correctness of context-aware feature models.\",\n \"Title: LOCCAM - loosely coupled context acquisition middleware\\nYear: 2013\\n\\nAbstract: Sensors of all kinds are being integrated with mobile and portable devices (tablets, smartphones). This opens up the possibility of context-aware applications to effectively be able to adapt their behavior, user interfaces and content according to the current user's situation. Frequently, context-aware applications require an infrastructure for acquisition, aggregation and reasoning of contextual information. However, existing context management infrastructures are not always appropriated to the heterogeneous and particular environment of mobile devices. In this paper, we present a context management middleware called LoCCAM (Loosely Coupled Context Acquisition Middeware) to provide self-adaptive acquisition of contextual information. It can execute both locally, on a single device, or distributed among nearby devices. The middleware proposes a model for publication, and notification of contextual information based on tuple spaces. As consequence, it offers a lower coupling among applications and the context acquisition layer. In this paper, we also present a performance evaluation of the adaptation mechanism.\",\n \"Title: Impact of Density, Load, and Mobility on the Performance of Routing Protocols in Vehicular Networks\\nYear: 2012\\n\\nAbstract: Designing routing protocols in vehicular network is a challenging task due to the high mobility of nodes, the instability of wireless links, and the diversity of deployment scenarios. Several routing protocols have been designed with the goal of solving one or more specific problems of each scenario. In this paper, we present a performance evaluation of routing protocols in vehicular networks addressing the impact of density, load, and mobility pattern. Four protocols are evaluated in urban and highway scenarios. The results presented in this paper provide guidelines for network designers in planning efficient routing protocols for vehicular network, able to adapt to different scenarios.\",\n \"Title: Integration of routing and time synchronization protocols for wireless sensor networks\\nYear: 2008\\n\\nAbstract: When dealing with Wireless Sensor Networks (WSN) applications that demand a high level cooperation of the sensor nodes, time synchronization is necessary to provide the correctness required for their results. In this work, we show that common issues between routing and time synchronization processes make their integration possible and, thus, can solve the problems of the resources consumption and time spent to acquire the synchronization. Two proposals for integrating them are presented.\",\n \"Title: An approach for semantic enrichment of software product lines\\nYear: 2012\\n\\nAbstract: Software Product Lines (SPLs) have evolved and gained attention as one of the most promising approaches for software reuse. Feature models are the main technique to represent domain variability in SPLs. However, there are other domain aspects, besides variability, which cannot be expressed in a feature model. Also, these diagrams were not designed to facilitate information retrieval, interoperability and inference. In contrast, ontologies seem to be the best solution to meet these requirements. Therefore, this work presents an approach for semantic enrichment of SPLs using ontologies. Our proposal provides methods to add domain information besides variability description, and a top-ontology that specifies generic concepts and relations in an SPL, working as a guide model for information addition. The proposed approach reuses the existing SPL feature model, adding semantic descriptions in a less intrusive way than modifying the feature model notation.\",\n \"Title: RefaX: A Refactoring Framework Based on XML\\nYear: 2004\\n\\nAbstract: Refactoring, i.e., the process of changing a software system to improve its internal quality and preserving its external behavior, is gaining increasing acceptance among software developers. Even though many refactoring tools are now available for a variety of programming languages, most of them are difficult to reuse, extend or even customize, mainly because they provide no uniform way of representing and manipulating source code information. This paper presents a refactoring framework, called RefaX, which relies on open, XML-based source code models and processing standards to facilitate the development, customization and reuse of refactoring tools. In particular, RefaX makes it possible to develop refactoring tools that are independent of source code model, programming language and XML processing technology. The viability of the framework is illustrated through a refactoring prototype for Java.\",\n \"Title: MobiS: A Solution for the Development of Secure Applications for Mobile Devices\\nYear: 2004\\n\\nAbstract: With the mobile computing evolution, portable devices have emerged in the market with the possibility of connection to IP\\n networks using wireless technologies. The migration from fixed terminals to wireless mobile devices and the increasing availability\\n of information for such devices impose new challenges in the development of applications. The security and the portability\\n are examples of these challenges that constitute the motivation for this work. Our main goal is to introduce a solution, called\\n MobiS (Mobility and Security), to the development of secure applications for data transmission using wireless technologies.\",\n \"Title: A framework for text visualization using memory traffic management for mobile devices\\nYear: 2009\\n\\nAbstract: Graphical User Interfaces (GUIs) of document viewers have gained attention with the increase on the number of mobile applications that uses it. However, mobile devices are still limited in relation to the available functionalities for text exhibition. Other limitations of these devices are the memory size, processing capacity and battery. This paper describes a framework for text visualization that safely manages memory traffic for mobile applications that intensively use bitmap font files, such as a document viewer. The main goal is to diversify the functionalities concerning to text exhibition in mobile devices, but also minimizing memory traffic.\",\n \"Title: Ubiquitous Software Engineering: Achievements, Challenges and Beyond\\nYear: 2011\\n\\nAbstract: Ubiquitous systems, or simply put Ubiquitous Sofware, are user-centric complex systems that must simultaneously deal with requirements such as mobility, portability, adaptability, interoperability and context-awareness, among others. In that direction, the last decades presented several Software Engineering techniques like frameworks and middlewares, component models, service-oriented architectures and software product lines, all trying to address and diminish the complexity to develop Ubiquitous Software. However, issues regarding the systematic development and proliferation of such software still lay untouched. Thus, it is mandatory to consider them, as well as to come up with production and commercialization models, in order to make the popularization of Ubiquitous Software plausible. Discussing these issues, this paper presents a summary of achievements on the development of Ubiquitous Software in the last decades, challenges ahead and future directions.\",\n \"Title: Industry is From Mars, Academia is from Venus\\nYear: 2011\\n\\nAbstract: In the last decades, the software industry and the Brazilian academia have been working more closely, mainly due to the incentives from funding agencies, such as CNPq, CAPES and FINEP, as well as tax incentives, like Brazil's Law of Informatics. As in any relationship, each party brings its own experiences, goals, targets and outcomes. Thus, for a partnership to be successful, it is important that each side learns how to deal with the differences, respecting the limits of each party, fostering mutual growth. In this context, the aim of this paper is to present the challenges faced by the GREat research group of the Federal University of Cear谩 over the past 10 years of industry partnership.\",\n \"Title: FrameIDTV: A framework for developing interactive applications on digital television environments\\nYear: 2010\\n\\nAbstract: Digital TV technologies are stretching out the horizons for interactive applications to end users. However, developing interactive applications for this new environment is not as straightforward as developing Internet applications. In order to make this development process easier in the context of interactive digital TV (iDTV), one of the solutions is the development of Frameworks. However, after investigating some of the existing iDTV framework solutions, we have found a limitation on the range of the interactive application domain to DTV available in these current frameworks, which mainly show solutions for local interactive (enhanced TV). Thus, in this paper, we propose an iDTV Framework (called FrameIDTV) that makes possible a broader solution in the DTV domain for the construction of interactive applications, both local and remote. The remote interactivity is possible using a generic and easy to customize communication protocol that is specified in the framework for the application layer. Furthermore, applications such as voting, home banking, and t-commerce, which are executed locally in the set-top box and are integrated to remote services using a return channel, can use the proposed framework. FrameIDTV also allows the establishment of secure communications and is developed following a specific framework methodology. This framework has primarily targeted the Brazilian Digital TV standard and its procedural middleware, called Ginga-J. Nevertheless, FrameIDTV can be broadly used worldwide, since it is compliant with the Globally Executable MHP (GEM) standard.\",\n \"Title: An adaptive context acquisition framework to support mobile spatial and context-aware applications\\nYear: 2013\\n\\nAbstract: The increasing number of mobile devices allows users to access applications anytime and anywhere. In such applications, location is a key information to improve the interaction between user and services. Existing applications combine location with other context information, such as weather, user's activity, temperature, among others. However, developing context-aware applications is still a non-trivial task due to the complexity to implement context management. Additionally, existing context management infrastructures are too brittle to handle changes in the underlying execution infrastructure. In this scenario, this work proposes a context acquisition framework, which tries to reduce the development complexity of mobile spatial and context-aware applications. The framework uses tuples space and OSGi to promote uncoupling and to adapt itself according to application requirements. A proof of concept was developed in order to show how spatial and context filters can be easily implemented during the development of a tracking application.\",\n \"Title: RepliX: Um Mecanismo para a Replicação de Dados XML\\nYear: 2007\\n\\nAbstract: XML has become a widely used standard for data exchange in ap- plications. Native XML DBMS are being developed to manage this data type. Such systems implement several characteristics that are common to traditional database systems. However, few of them provide replication mechanisms. The group communication abstraction is an efficient technology for implementing re- plication protocols since it provides reliability guarantees. This paper presents RepliX, a mechanism for XML data replication based on group communication. In order to evaluate RepliX, experiments measuring performance and availabi- lity were conducted.\",\n \"Title: FramePersist: An Object Persistence Framework for Mobile Device Applications\\nYear: 2004\\n\\nAbstract: Traditional requirements for persistence layers do not consider limitations of the development platforms available for mobile devices. In order to facilitate the development of applications, which need to store data, for mobile devices, these traditional requirements are reevaluated in this paper and a framework for object persistence is proposed. This framework, called FramePersist, is constructed based on the concept of object serialization and allows to persist and to search objects efficiently. Mapping rules of objects for persistence are presented together with a case study using the Symbian OS native file systems.\",\n \"Title: Considerations on developing mobile applications based on the Capuchin project\\nYear: 2010\\n\\nAbstract: The development of applications for mobile devices is becoming increasingly popular, with manufacturers struggling to support different programming environments and embedding libraries on their devices. In this pursuit for a straight-forward development of mobile applications, Java Micro Edition (JME) is a natural solution. Although JME has innumerous benefits, it offers limited support for user interface (UI) development. On a different path, Adobe's Flash Lite is tailored to develop rich UI for mobile applications. To bring together the advantages of both JME and Flash Lite, Sony Ericsson's Capuchin project permits the creation of interactive mobile applications, using Flash Lite to implement the user interface and JME to implement application core. The use of Flash Lite and JME in a single application has rised design issues that must be dealt by software engineers, such as performance, maintainability and reusability of both Flash Lite and JME programming languages. To guide software engineers design mobile applications, this paper presents a development process for interactive mobile applications based on Capuchin project. To validate it, a mobile application is developed based on this process, and relevant topics of the process are discussed.\",\n \"Title: Framework for building intelligent mobile social applications\\nYear: 2012\\n\\nAbstract: The use of online social networks (OSN) has been a reality for some years now. If OSN users have mobile devices and they are taken into account, every day a vast amount of information is spontaneously generated, creating opportunities for researchers and developers to use, for example, artificial intelligent techniques to explore similarities between friends, to recommend content and to come up with business opportunities. Additionally, OSN and mobile devices can be put together to explore user context to tailor services according to the user environment. However, to apply ubiquitous computing and artificial intelligence to OSN can be cumbersome and resource-consuming. Thus, this paper presents a framework to develop intelligent applications on top of existing OSN, helping developers to explore similarities between the users and recommend content, using user context and simple information present on OSN, without compromising resources present in mobile devices. At the end, this paper shows how to develop new applications using the framework exploring user context and semantic concepts defined by the developer.\",\n \"Title: Improving network management with mobile agents in peer-to-peer networks\\nYear: 2008\\n\\nAbstract: Regarding the size and the complexity growth of today's networks, several network management models have been studied and proposed. Furthermore, new requirements emerge with the interaction among entities that compose the management system, such as interoperability, collaboration among managers geographically separated, resources sharing, load balancing and inter-domain manager. It occurs that many of these models don't worry about the network logical configuration. In this paper, we present an improvement in the network management by combining P2P-Based Management System and Mobile Agents. The idea is to provide a mobile agent system extension for its integration with an architecture of network management based on Peer-to-Peer (P2P) networks. The mobile agent system makes it possible to have a more robust and self-organized network, together with the distributed system benefits.\",\n \"Title: An Aspect-Oriented Programming Model for Bag-of-Tasks Grid Applications\\nYear: 2007\\n\\nAbstract: This paper presents a novel programming model for explicitly separating parallelization and middleware-specific concerns in bag-of-tasks (BoT) grid applications. The model uses Java threads for application decomposition, and aspect-oriented programming to dynamically (and transparently) convert the application's thread objects into independent grid tasks, using the services of a specific grid middleware API. This paper also describes early experimental results showing the model's modularity gains and performance overhead, when applied to implement BoT grid applications using OurGrid.\",\n \"Title: Requirements and challenges for building service-oriented pervasive middleware\\nYear: 2009\\n\\nAbstract: The dinamicy and uncertainness of resources in mobile networks ask for novel uncoupled, adaptable and autonomous programming abstractions. Although applications are built upon a middleware layer that encapsulates some of that complexity, there is a lot left to fully explore the potential of ubiquitous and pervasive systems. To provide an insight on the challenges to develop interoperable middleware systems, this paper highlights the requirements to build service-oriented ubiquitous and pervasive middleware. These requirements are divided into primary and cross-cutting requirements. Primary requirements are Message Exchange, Mobility Support, Service Description, Discovery and Coordination, and Security. While Cross-cutting requirements are Context-Awareness and Adaptability, Autonomy, and QoS Requirements.\",\n \"Title: Testing Requirements For Mobile Applications\\nYear: 2009\\n\\nAbstract: Wireless networks have contributed to the technological advance that popularized the use of mobile devices, and fostered the development of applications targeted to these devices. However, issues such as mobility and communication intermittency, as well as processing, storage and battery constraints demand changes in the traditional software testing process. This paper aims to present testing requirements that are specific to applications developed for mobile devices. We also show that these requirements can improve productivity and efficacy in the testing process of an application.\",\n \"Title: RETENTION: A reactive trust-based mechanism to detect and punish malicious nodes in ad hoc grid environments\\nYear: 2013\\n\\nAbstract: In ad hoc grid environments, resources are not always available since nodes can spontaneously connect and disconnect at any time. Thus, these environments demand the correct execution of tasks to guarantee good performance. However, there are malicious users that affect the normal operation of these grids. These users modify tasks results and even cheat security mechanisms. Therefore, to assure high performance in these grid computing scenarios, it is essential to use punishment procedures based on trust models. These solutions have been used in wireless ad hoc networks, but not in the context of ad hoc grid computing. Thus, in this paper, we first present an analysis of mathematical trust models in ad hoc grid scenarios, using different ways to treat detection information passed on by other nodes. Then, we provide a comparison and a performance evaluation of these models using a grid simulator platform. Besides that, we choose the most accurate trust model among the evaluated ones to propose RETENTION: a reactive trust-based mechanism to detect and punish malicious nodes in ad hoc grid environments. Simulation results demonstrate the effectiveness of the proposed approach in detecting and punishing up to 100% of malicious nodes without generating false-positives. The results can be a valuable tool for network designers in planning trust models in ad hoc grid network deployments.\",\n \"Title: Applying Artificial Neural Networks for Fault Prediction in Optical Network Links\\nYear: 2004\\n\\nAbstract: The IP+GMPLS over DWDM model has been considered a trend for the evolution of optical networks. However, a challenge that has been investigated in this model is how to achieve fast rerouting in case of DWDM failure. Artificial Neural Networks (ANNs) can be used to generate proactive intelligent agents, which are able to detect failure trends in optical network links early and to approximate optical link protection mode from 1:n to 1+1. The main goal of this paper is to present an environment called RENATA2 and its process on how to develop ANNs that can give to the intelligent agents a proactive behavior able to predict failure in optical links.\",\n \"Title: SLeSS: A Scrum and Lean Six Sigma Integration Approach for the Development of Sofware Customization for Mobile Phones\\nYear: 2011\\n\\nAbstract: The development of embedded software for mobile phones requires a thorough knowledge of development processes, technologies and constraints related to software and hardware. Moreover, the growing competitiveness of this niche demands high productivity and quality. In this way, there is a need to invest in continuous improvement of processes, research for new technologies and methodologies, and increasing project performance to meet client needs and expectations. This paper proposes SLeSS, an integration approach of Scrum and Lean Six Sigma used in real projects of developing embedded software customizations for mobile phones. This approach enables the achievement of performance and quality targets, progressively improving the development process and the outcome of projects.\",\n \"Title: GeoSPIN: An Approach for Geocast Routing Based on SPatial INformation in VANETs\\nYear: 2013\\n\\nAbstract: Vehicular Ad hoc NETworks (VANETs) have been widely used to provide data exchange services in Intelligent Transport Systems (ITS), which should facilitate user's routines. At the same time that user's routines are improved, they can also be used as an important source of data for helping the decision-making process of VANET services. These routines can be acquired from vehicle's trajectories through the use of Global Positioning Systems (GPS). In this context, the combination of location-based data and data forwarding methods brings interesting challenges since these topics are not directly related. Therefore, the key idea of this work is to provide a geocast routing mechanism in VANETs based on daily movements of users in their vehicles. The main contribution is related to the delivery rate, which increases in partitioned and sparsely connected networks. The results show the efficiency of our new method to perform opportunistic routing based on location data, which discovers the best routes to forward packets through the network.\",\n \"Title: Improving photo recommendation with context awareness\\nYear: 2012\\n\\nAbstract: One of the most important challenges in Information Systems is information overload. Recommender Systems try to cope with this problem by helping people in retrieving information (ex: videos, services, products, images, etc.) that may match their preferences and intentions. An issue of Recommender Systems is related to user's context. The use of the system in a different context than usual may cause an unsatisfactory result for the recommendation, since preferences and intentions can be influenced by user's context (location, trajectory, time of day, activity, etc.). This paper presents the MMedia2U, a mobile photo recommender system that exploits the user's context and the context when photo was created as a means to improve the recommendation. Three context dimensions area exploited: spatial, social and temporal. We describe the similarity measures used for each dimension and the results of the system evaluation with 13 users following a Gold Standard approach.\",\n \"Title: A Decoupled and Interoperable Architecture for Coordination in Ubiquitous Systems\\nYear: 2011\\n\\nAbstract: Com o avanço das tecnologias de hardware, como o surgimento de computadores menores com maior poder de processamento e armazenamento, e o progresso da comunicação de dados sem fio, a Computação Ubíqua se tornou uma realidade. Entretanto, o desenvolvimento de sistemas ubíquos ainda apresenta inúmeros desafios devido à grande diversidade e complexidade dos seus requisitos. Particularmente, em ambientes ubíquos onde a dinamicidade e a heterogeneidade de dispositivos e serviços são características comuns, a coordenação desacoplada e interoperável das atividades realizadas entre os agentes de software do sistema torna-se essencial. Assim, esse trabalho propõe uma arquitetura que proporciona meios de interação e coordenação desacoplados e interoperáveis para o desenvolvimento de sistemas ubíquos.\",\n \"Title: A Method for Model Checking Context-Aware Exception Handling\\nYear: 2013\\n\\nAbstract: The context-aware exception handling (CAEH) is an error recovery technique employed to improve the ubiquitous software robustness. In the design of CAEH, context conditions are specified to characterize abnormal situations and used to select the proper handlers. The erroneous specification of such conditions represents a critical design fault that can lead the CAEH mechanism to behave erroneously or improperly at runtime (e.g., abnormal situations may not be recognized and the system's reaction may deviate from what is expected). Thus, in order to improve the CAEH reliability this kind of design faults must be rigorously identified and eliminated from the design in the early stages of development. However, despite the existence of formal approaches to verify context-aware ubiquitous systems, such approaches lack specific support to verify the CAEH behavior. This work proposes a method for model checking CAEH. This method provides a set of modeling abstractions and 3 (three) properties formally defined that can be used to identify exiting design faults in the CAEH design. In order to assess the method feasibility: (i) a support tool was developed, and (ii) fault scenarios that are recurring in the CAEH was injected in a correct model and verified using the proposed approach.\",\n \"Title: MobiLine: A Nested Software Product Line for the domain of mobile and context-aware applications\\nYear: 2013\\n\\nAbstract: Mobile devices are multipurpose and multi-sensor equipments supporting applications able to adapt their behavior according to changes in the user's context (device, location, time, etc.). Meanwhile, the development of mobile and context-aware software is not a simple task, mostly due to the peculiar characteristics of these devices. Although several solutions have been proposed to facilitate their development, reuse is not systematically used throughout the software development life-cycle. In this paper, we discuss an approach for the development of mobile and context-aware software using the Software Product Line (SPL) paradigm. Furthermore, a Nested SPL for the domain of mobile and context-aware applications is presented, lessons learned in the SPL development are discussed and a product for a context-aware visit guide is shown.\",\n \"Title: An adaptation of the collections framework, reflection and object cloning from J2SE to J2ME\\nYear: 2008\\n\\nAbstract: The jargon used by Sun Microsystems related to the Java technology \\\"write once, run anywhere\\\" does not match the reality when it comes to devices with distinct memory and processing capability as can be evidenced by software engineers in migration projects between J2SE and J2ME platforms. This work proposes a solution on how to port conventional desktop-tailored codes to less capable mobile devices, achieving the same results, with comparative examples that use the Collections framework classes, and the object cloning and reflection resources. Moreover, this paper shows a case study where the proposed process is applied.\",\n \"Title: P2PScheMe: a P2P scheduling mechanism for workflows in grid computing\\nYear: 2012\\n\\nAbstract: Complex scientific experiments have a growing demand for computational resources, which are expensive to be acquired and maintained. Grid computing has emerged as the mainstream technology to solve this issue. Grids are also adequate for the execution of scientific workflows because they allow the use of heterogeneous and distributed resources. In spite of the progress in grid technology, there are challenges to overcome in workflow scheduling. For instance, centralized scheduling solutions may lead to performance degradation and to problems with scalability. Some scheduling approaches are partially distributed, keeping a few centralized components that may become bottlenecks. Other distributed solutions have a lack of flexibility in the definition of workflows, in which only the use of tasks as steps in the workflow is permitted not high level services. In this work, we present P2PScheMe, a scheduling mechanism for peer-to-peer execution of workflows based on the invocation of grid services. The proposal considers information regarding grid execution environment in order to allow workflow scheduling adaptation. This adaptation is performed according to user requirements of quality of service. In this paper, we describe how P2PScheMe works and provides a comparative analysis with existing solutions. Copyright © 2011 John Wiley & Sons, Ltd.\",\n \"Title: An Architecture Proposal for Nested Software Product Lines in the Domain of Mobile and Context-Aware Applications\\nYear: 2010\\n\\nAbstract: The domain of mobile and context-aware applications involves challenging requirements, such as mobility and adaptation, which makes the application development complex for this area. Considering this scenario, we used a nested software product line (SPL) that aims to facilitate the construction of such software by domain decomposition in two levels of analysis. The first concerns the characteristics of a generic SPL for the mobile and context-aware domain. The second is the requirement analysis of a business domain together with characteristics of the generic level. The goal of this paper is to propose a nested SPL.\",\n \"Title: Mobile Photo Recommendation and Logbook Generation Using Context-Tagged Images\\nYear: 2014\\n\\nAbstract: Context-aware and semantic-based technologies have been successfully employed to improve multimedia management in mobile environments. Large sets of context-tagged images on the Web are a concrete example of this achievement. The authors present two mobile systems, MMedia2U and CAPTAIN, that take the concept of context-aware multimedia management beyond photo organization and annotation. CAPTAIN is a tool that helps generate logbooks using context-tagged images and tracking data. Crewmembers used this tool to manage multimedia content and publish it to a blog during a sea expedition. MMedia2U is a mobile photo recommender system that exploits the user's context and context-tagged images to improve photo recommendation.\",\n \"Title: XMobile: A MB-UID environment for semi-automatic generation of adaptive applications for mobile devices\\nYear: 2008\\n\\nAbstract: Ubiquitous Computing promises seamless access to information anytime, anywhere with different and heterogeneous devices. This kind of environment imposes new challenges to software development. For example, information and user interface should be adapted according to contextual characteristics such as user, environment, and access device. In case of device adaptation, the development challenge is related to the heterogeneity of the devices, which requires software engineers to create different versions for each type of device and every platform. This paper proposes a MB-UID (model-based user interface development) approach for semi-automatic generation of adaptive applications for mobile devices. An environment, called XMobile, offers a device-independent user interface framework and a code generation tool for providing fast development of multi-platform and adaptive applications according to device and platform features. A case study is also presented to illustrate how the environment can be used for constructing an application for heterogeneous devices with different network connectivity modes.\",\n \"Title: Regularized Supervised Distance Preserving Projections for Short-Text Classification\\nYear: 2014\\n\\nAbstract: Short-text classification is a challenging natural language processing problem. Beyond classification accuracy, another issue refers to the dimensionality of the feature vectors used for classification. This is especially important for embedded applications with hard constraints of computational power and memory. To deal with such problems, many techniques of dimensionality reduction have been developed over the last years. The Supervised Distance Preserving Projections (SDPP) has shown promising results. This work proposes a modified version of the SDPP method, called Regularized SDPP, which relies on the regularization theory. On the basis of experimental evaluation, the proposed approach has achieved good results in comparison to the state-of-the-art methods in nonlinear dimensionality reduction.\",\n \"Title: Performance issues with routing in multi-channel multi-interface IEEE 802.11s networks\\nYear: 2014\\n\\nAbstract: Wireless Mesh Networks have the potential to serve as an all-wireless backbone. They represent a key building block of the new Internet of Things to collect all the traffic. However, IEEE 802.11 performs very poorly in multi-hop topologies leading to unfairness and a poor throughput. Thus, the standard IEEE 802.11s proposes to re-use the IEEE 802.11 medium access in a mesh multi-hop topology while using a routing protocol to create routes at the layer 2. IEEE 802.11s may exploit multi-channel multi-interface wireless routers to increase the through-put. In particular, the routing protocol must select carefully the forwarders to limit inter- and intra-flow interference. In this paper, we propose to fully characterize the performance of IEEE 802.11s when using multi-interface nodes, and to isolate some key performance issues. We also propose some key mechanisms that must be implemented to solve these pathological cases and to improve the throughput.\",\n \"Title: USABle -- A Communication Framework for Ubiquitous Systems\\nYear: 2014\\n\\nAbstract: The widespread use of mobile devices is reshaping the way users interact, allowing applications to explore physical proximity of devices to offer intelligent services. Although there are several communication technologies available (e.g., Wi- Fi, Wi-Fi Direct, LTE, UMTS, Bluetooth, NFC), building an application from scratch considering both communication and application requirements is not a trivial task. In order to help developers to implement communication primitives, this paper presents a communication framework for ubiquitous systems called USABle. Two important contributions of this framework can be highlighted: i) a set of technology-independent interfaces to handle communication requirements; and ii) a modular and extensible layer-based architecture that permits developers to implement new communication technologies and message dissemination strategies. The outcome of using this communication framework is a simpler way to build applications that explore physical proximity. To validate the claims presented in this paper, a performance evaluation using real devices is done, analyzing two multi-hop and three carry-and-forward implementations of routing algorithms that were implemented using the USABle framework.\",\n \"Title: How to Describe SPL Variabilities in Textual Use Cases: A Systematic Mapping Study\\nYear: 2014\\n\\nAbstract: In the Software Product Line (SPL) paradigm, the variability description is an important issue for the requirements engineering process. In this scenario, there are several approaches in the literature focusing on how to describe variability in use cases. However, to the best of our knowledge, no efforts have been made to collect and summarize the existing templates for textual use case description in the SPL paradigm. This paper addresses this gap, presenting a systematic mapping study about SPL variability description in textual use cases. We found with this mapping, nine use case templates and four different ways to describe SPL variabilities in a use case description. From these templates, only one deal with the five variability types identified and we did not find any experimental study comparing these templates in terms of ease of use or comprehensibility.\",\n \"Title: EPMOSt: an energy-efficient passive monitoring system for wireless sensor networks.\\nYear: 2014\\n\\nAbstract: Monitoring systems are important for debugging and analyzing Wireless Sensor Networks (WSN). In passive monitoring, a monitoring network needs to be deployed in addition to the network to be monitored, named the target network. The monitoring network captures and analyzes packets transmitted by the target network. An energy-efficient passive monitoring system is necessary when we need to monitor a WSN in a real scenario because the lifetime of the monitoring network is extended and, consequently, the target network benefits from the monitoring for a longer time. In this work, we have identified, analyzed and compared the main passive monitoring systems proposed for WSN. During our research, we did not identify any passive monitoring system for WSN that aims to reduce the energy consumption of the monitoring network. Therefore, we propose an Energy-efficient Passive MOnitoring SysTem for WSN named EPMOSt that provides monitoring information using a Simple Network Management Protocol (SNMP) agent. Thus, any management tool that supports the SNMP protocol can be integrated with this monitoring system. Experiments with real sensors were performed in several scenarios. The results obtained show the energy efficiency of the proposed monitoring system and the viability of using it to monitor WSN in real scenarios.\",\n \"Title: Templates for textual use cases of software product lines: results from a systematic mapping study and a controlled experiment\\nYear: 2015\\n\\nAbstract: Use case templates can be used to describe functional requirements of a Software Product Line. However, to the best of our knowledge, no efforts have been made to collect and summarize these existing templates and no empirical evaluation of the use cases’ comprehensibility provided by these templates has been addressed yet. The contributions of this paper are twofold. First, we present a systematic mapping study about the SPL variability description using textual use cases. From this mapping, we found twelve SPL use case templates and observed the need not only for the application of these templates in real SPL but also for supporting tools. Secondly, this work presents an evaluation of the comprehensibility of SPL use cases specified in these templates through a controlled experiment with 48 volunteers. The results of this experiment show that the specification of variabilities in the steps’ numeric identifiers of the textual use cases is better to the use case understanding than the other approaches identified. We also found evidence that the specification of variabilities at the end of the use cases favors the comprehension of them and the use of questions associated to the variation points in the use cases improves the understanding of use cases. We conclude that each characteristic of the existing templates has an impact on the SPL use case understanding and this should be taken into account when choosing one.\",\n \"Title: A pattern language for agile software estimation\\nYear: 2012\\n\\nAbstract: This paper presents a pattern language for agile software estimation. The proposed language is composed of eight patterns and their relationships, which were identified through an extensive literature research and interviews with several companies that use agile methodologies. The patterns identified can help agile teams to obtain the main estimates needed in the context of agile software projects.\",\n \"Title: Conflict of requirements: a pattern for the treatment of conflicting non-functional requirements\\nYear: 2012\\n\\nAbstract: Software development is an activity that works several aspects of Software Engineering. One of them is requirements elicitation and its writing in an understandable notation for software developers. Non-Functional Requirements are those associated to the qualitative aspects of software such as performance, safety and usability. Normally the identification of non-functional requirements is conducted on an adhoc basis, and developed later. In this paper, a pattern is proposed for the treatment (identification and selection) of conflicting non-functional requirements in the early stages of its development, to not harm the quality of the system and also to be more suitable to customer needs.\",\n \"Title: MLM-rank: A Ranking Algorithm Based on the Minimal Learning Machine.\\nYear: 2015\\n\\nAbstract: Ranking is an important task in information retrieval and has gained much attention in recent years. Among the most used strategies, machine learning has achieved important results. The current work proposes a new machine learning based ranking algorithm, the MLM-RANK. MLM-RANK is based on the recently proposed Minimal Learning Machine (MLM). MLM is a supervised learning method that requires the adjustment of a single hyper parameter. The proposed method was evaluated against Prank and ELM Rank, both state of the art point wise ranking methods. In these tests MLM-RANK achieved promising results.\",\n \"Title: Towards a formal model to reason about context-aware exception handling\\nYear: 2012\\n\\nAbstract: The context-awareness is a central aspect in the design of pervasive systems, characterizing their ability to adapt its structure and behavior. The context-aware exception handling (CAEH) is an existing approach employed to design exception handling in pervasive systems. In this approach, the context is used to define, detect, propagate, and handle exceptions. CAEH is a complex and error prone activity, needing designers' insights and domain expertise to identify and characterize contextual exceptions. However, despite the existence of formal methods to analyze the adaptive behavior of pervasive systems, such methods lack specific support to specify the CAEH behavior. In this paper, we propose a formal model to reason about the CAEH behavior. It comprises an extension of the Kripke Structure to model the context evolution of a pervasive system and a transformation function that derivates the CAEH control flow from that proposed structure.\",\n \"Title: Analyzing the Feature Models Maintainability over their Evolution Process: An Exploratory Study.\\nYear: 2016\\n\\nAbstract: The feature model is one of the most important artifact of a Software Product Line (SPL). It is built in the early stages of SPL development and describes the main features and relationships. The feature model evolves according to the evolution of the SPL. Thus, it is important to build maintainable feature models. In this scenario, measures have been proven useful in the maintainability evaluation of the feature models. This paper presents an exploratory study on the impact of feature models maintainability over the SPL evolution process. In order to support this analysis, we built a dataset containing a compiled set of 21 maintainability structural measures extracted from 16 feature models and respective versions. Although not conclusive, our findings indicate that the feature models maintainability tends to decrease as it evolves. We also identified the most common changes performed in a feature model during its evolution process.\",\n \"Title: A service-oriented architecture for billing resources in IaaS cloud platforms\\nYear: 2015\\n\\nAbstract: Cloud Computing is a recent paradigm where different IT resources, such as applications or hardware, are quickly provisioned to customers through a pay per use model. Many research studies have already been conducted concerning billing services for cloud computing, but they lack on flexibility to establish how resources are defined and monitored. In fact, current solutions seem also very dependent on specific cloud infrastructures. This paper proposes an architecture for billing cloud services decoupled from specific providers, named as aCCountS. This service is complemented by a Domain Specific Language that allows the specification of flexible pricing policies. Such policies aims at supporting cloud billing requirements collected from our literature survey, allowing pricing schemes that meet different customer profiles. Based on this architecture, a prototype has been implemented and tested to validate our proposal in two different cloud infrastructures. Experiments confirmed that (i) the architecture hasn't dependencies of specific IaaS provider and (ii) the charging procedures are done correctly.\",\n \"Title: Adaptive Tracking Model in the Framework of Medical Nursing Home Using Infrared Sensors\\nYear: 2015\\n\\nAbstract: On Internet of Things (IoT), everything can be accessed anytime, anywhere, and works without human intervention. In IoT everything collaborates to deliver services and applications to users, Ambient Assisted Living (AAL) being one of these applications. Some AAL smart homes uses infrared sensors to recognize some activities of daily living and to track people along the environment. Location tracking is vital in Ambient Assisted living and can be a useful information to improve AAL systems. A common problem in such systems is that each tracking model is based on a specific sensor's placing architecture. In order to assure that the system will work properly, the model has to be fitted by an expert. Modeling is usually costly and it relies on a specific architecture. In our previous work, the tracking model needed to be fitted manually. In order to introduce adaptability, this work proposes an approach to automatically fit the model avoiding the need of an expert to fit a different model for each kind of sensor's placing architecture. The proposed approach was evaluated using real data from a set of pyroelectric infrared sensors and a set of scenarios performed in a simulated apartment.\",\n \"Title: Using the GQM Method to Evaluate Calmness in Ubiquitous Applications\\nYear: 2015\\n\\nAbstract: Ubiquitous systems change the way users interact with computers, because their services must be available everywhere at any time, supporting users in various everyday activities. An essential element for these systems is their calm interaction with users, which means the system should not disturb them unnecessarily. Literature currently lacks work focusing on how to evaluate calmness and case studies made in a real usage situation. The aim of this work is to propose a model, defined using the Goal-Question-Metric GQM method, for calmness evaluation in ubiquitous systems and to show our results from a case study with three ubiquitous applications.\",\n \"Title: Mobile phone text messaging to increase student participation: an experience in a blended course.\\nYear: 2016\\n\\nAbstract: Mobile technology is a suitable tool to be used for learning purposes. Many research studies prove the benefits of Mobile Learning (m-learning) in various education disciplines. Following this trend, our study examined a post-graduate class consisting of 474 learners in which Short Message Service (SMS) was used. The main goal was to find out if this technology would increase student participation in the course. The lecture series were implemented by using a blended learning approach, in which the courses combine face-to-face classes with online activities. Two groups of learners were created, control and experimental, in order to analyze the activities' fulfillment rate and the response time. The results from the data analysis showed that students who received mobile messaging outperformed significantly students from the control group. The experimental group had better results both in completion rate and response time. They were almost 20% more effective at completing their assigned activity and up to 78 hours faster than students from the control group. In addition, a questionnaire answered by the experimental group demonstrated that participants were very satisfied with the usage of this technology and were enthusiastic about the use of messages on the course.\",\n \"Title: Towards a component infrastructure for cyber-physical systems.\\nYear: 2016\\n\\nAbstract: The proximity between physical and cyber worlds is permitting the appearance of Cyber-Physical Systems (CPS), formed by users and devices (physical) interacting with services, components and applications (cyber). In CPS, where unpredictability is an important challenge, two characteristics must be present in the developed systems: i) low coupling among interacting modules and ii) self-adaptive capabilities. In that direction, this paper describes an uncoupled sensor and actuator component-based infrastructure for self adaptive CPS. Its main contribution is two-fold: i) a lightweight and interoperable mechanism to specify and manage sensors and actuators, built on top of an ii) uncoupled communication and coordination mechanism for cyber-physical entities.\",\n \"Title: Design and usability of a braille-based mobile audiogame environment.\\nYear: 2016\\n\\nAbstract: The rise of digital technologies brought positive changes to the lives of people who are blind. However, they are gradually making Braille less attractive and diminishing its importance. In this context, we investigate whether mobile games can be useful to improve the Braille practice through language exercises, for students with visual disabilities. We present the Game Braille Environment (GBraille), a suite composed of audiogames and a mobile virtual keyboard based on the metaphor of Braille's 6-dots cells system. GBraille Keyboard provides a text-based mechanics to mobile games. GBraille audiogames offer Portuguese and Spanish language exercises. We implemented an initial evaluation study of GBraille audiogames and GBraille Keyboard including Brazilian students with visual disabilities and Chilean and Brazilian special education teachers. Preliminary results are promising and indicate a good level of acceptance by students who are blind, who were able to perform the evaluation tasks.\",\n \"Title: Requirements Engineering and Variability Management in DSPLs Domain Engineering: A Systematic Literature Review.\\nYear: 2016\\n\\nAbstract: Recently, Software Product Lines (SPLs) have been used successfully for building products families. However, the currently and complex software products demand more adaptive features. Today, many application domains demand capabilities for flexible adaptation and post-deployment reconfiguration. In this context, Dynamic Software Product Lines (DSPLs) represent a way to produce software products able to change their own behavior at runtime due to the changes in the product use environment. DSPLs present some interesting properties such dynamic variability and reconfiguration at runtime. The dynamic variability is represented by the definition of variants and context information. The reconfiguration at runtime is the process that enables the features activation and deactivation in a configuration product. Both properties are closely related to the requirements engineering and variability management, in the domain engineering life-cycle. In this research, we provide a systematic literature review that aims to identify the activities, assets, tools and approaches that are used in requirements engineering and variability management in DSPLs domain engineering. We performed a manual and automatic search, resulting in 581 papers of which 37 were selected. We also provide a discussion about the challenges and solutions of runtime variability mechanisms in the context of DSPLs.\",\n \"Title: DyMMer: a measurement-based tool to support quality evaluation of DSPL feature models.\\nYear: 2016\\n\\nAbstract: For Dynamic Software Product Lines (DSPLs), evaluating the quality of a feature model is important to ensure that errors in the early stages do not spread throughout the DSPL. Measures extracted from feature models have been proved to be useful in the quality evaluation of such models. However, the process used for computing the values of these quality measures for a large set of feature models can be cumbersome and error prone. To cope with this problem, we present DyMMer, a tool to support the automatic extraction of quality measures from feature models in DSPLs. After that, we can analyse the results and propose improvements for the feature models. Currently, the DyMMer tool is able to collect 40 different quality measures from a DSPL feature model.\",\n \"Title: Model Verification of Dynamic Software Product Lines.\\nYear: 2016\\n\\nAbstract: Dynamic Software Product Lines (DSPLs) extend the concept of Software Product Lines enabling adaptation at runtime according to context changes. Such dynamic behavior is typically designed using adaptation rules, context-triggered actions responsible for features activation and deactivation at runtime. The erroneous specification and the interleaving of adaptation rules (i.e., the parallel execution of adaptation rules) can lead DSPL to reach an undesired (improperly or defective) product configuration at runtime. Thus, in order to improve the reliability of DSPL behavior, design faults must be rigorously identified and eliminated in the early stages of DSPL development. In this paper, we address this issue introducing Dynamic Feature Transition Systems (DFTSs) that allow the modeling and formal verification of the DSPLs adaptive behavior. These transition systems are derived from the adaptation rules and a Context Kripke Structure, which is a context evolution model. Furthermore, we formally define five properties that can be used to identify existing design faults in DSPL design. Aiming to assess the feasibility of our approach, a feasibility study was conducted using two DSPLs, Mobile Visit Guides and Car. In both cases, design faults were automatically detected indicating that our formalism can help in the detection of design faults in the DSPLs adaptive behavior.\",\n \"Title: Investigating the Mode in Multimodal Video Games: Usability Issues for Learners who are Blind.\\nYear: 2017\\n\\nAbstract: This paper presents an ongoing work on methods for usability evaluation of audio- and haptic-based video games for learners who are blind. We report a Standard Usability Problem List which we envision to be the basis for comparison of the Usability Evaluation Methods (UEM) in this context. In addition, we present a preliminary analysis of evidence on what problems different UEMs can reveal by evaluating audio, interaction mode, interface adaptation, and feedback.\",\n \"Title: Fifteen Years of Industry and Academia Partnership: Lessons Learned from a Brazilian Research Group.\\nYear: 2017\\n\\nAbstract: In Brazil, software industry and academia have formed partnerships more often due to funding agencies and tax incentives originated, for example, from Brazil's Informatics Law. Like in many relationships, each party brings different experiences, and goals to be achieved. However, for a partnership to be successful, it is necessary to learn how to deal with these differences, respecting the limits of each party and fostering mutual growth. The aim of this paper is to present challenges and lessons learned faced by the GREat research group at the Federal University of Ceará over the past 15 years of partnership with industry. Besides, we present the GREat Business process for projects with industry and how the software engineering evolved in our group within these projects. We believe this report can help other industry and academic partnerships around the world not only because our main partners are international companies but also because what we have learned from practice is globally applied.\",\n \"Title: Generating test cases and procedures from use cases in dynamic software product lines.\\nYear: 2017\\n\\nAbstract: Software engineering is systematically evolving to address the production of families of systems instead of single products. This evolution comes at a price, it is now essential to deal with variability at both design and execution time. Developing test cases and procedures for a whole family of systems considering this dynamicity (variability at runtime) can be challenging. We propose a method to generate tests from use case specifications expressed in a controlled natural language, yet considering the variability and dynamicity in those specifications. We evaluate our method against use case specifications of a family of mobile and context-aware systems. Experimenting our method, we could measure that developing test cases and procedures becomes around 40+ faster when using our approach, opposed to manual development of tests under the same conditions.\",\n \"Title: ReMINDER: An Approach to Modeling Non-Functional Properties in Dynamic Software Product Lines.\\nYear: 2017\\n\\nAbstract: This paper presents a systematic approach to modeling NFPs in DSPL feature models. In our proposed approach, feature models are annotated with the representation of NFPs, rules for the activation and deactivation of features, constraints between NFPs and features, and context adaptation scenarios. To evaluate the applicability of the proposed approach we carried out an empirical evaluation. The approach yielded good results at identifying NFPs in DSPLs.\",\n \"Title: DyMMer-NFP: Modeling Non-functional Properties and Multiple Context Adaptation Scenarios in Software Product Lines.\\nYear: 2017\\n\\nAbstract: In Software Product Lines (SPLs), the modeling of nonfunctional properties (NFPs) and context adaptation scenarios are important activities, once they make possible the identification of interdependencies constraints between functional requirements (FR) and NFP, according to a specific adaptation context scenario. However, there are few tools to help domain engineers to represent NFPs and context adaptation scenarios. To deal with this problem, we propose DyMMerNFP, an extension of the DyMMer tool to support the modeling of NFPs and multiple contextual adaptation scenarios in feature models. DyMMer-NFP uses a catalog with 39 NFPs. Each NFP in this catalog were mapped according to each quality characteristic and subcharacteristics presented in the ISO/IEC 25010 SQuaRE product quality model. To specify the interdependencies between NFPs and features, DyMMer-NFP has used the concept of contribution links. In order to make it easier to evaluate DyMMer-NFP two datasets, called AFFOgaTO and ESPREssO, were made available for free.\",\n \"Title: Evaluating An Iot Application Using Software Measures\\nYear: 2017\\n\\nAbstract: Internet of Things (IoT) allows daily objects, with computing and communication capabilities, to connect to the Internet. In this scenario, an application called GREatRoom runs in an IoT environment, which has distributed wireless labels in places and objects, to detect the presence of nearby users, providing services intuitively and efficiently. Considering that IoT systems have quality characteristics of human-computer interaction similar to those of ubiquitous systems, this paper investigates the applicability of software measures from ubiquitous to IoT systems and presents the positive results achieved in this evaluation.\",\n \"Title: When Technology Supports Urban Mobility: Improvements for Mobile Applications Based on a UX Evaluation.\\nYear: 2017\\n\\nAbstract: The development of applications that helps urban mobility has been pushed by the increase of processing capacity and miniaturization of the mobile device as well as the improvement of speed and availability of Internet. Such applications can support users in several activities such as tracing routes and searching for addresses. In this scenario, this work aims to: (i) understand how users use urban mobility applications; (ii) evaluate the quality of interaction and interface into real applications called “Waze” and “Meu Onibus”; and (iii) improve the applications based on the results of the evaluations. Moreover, this study also suggests a set of recommendations for urban mobility applications in developing countries like Brazil.\",\n \"Title: What Changes From Ubiquitous Computing To Internet Of Things In Interaction Evaluation?\\nYear: 2017\\n\\nAbstract: Internet of Things (IoT) is a new paradigm that includes a network of smart objects, which are embedded sensors, communicating using the Internet. One of the areas that are leading up to IoT is Ubiquitous Computing (UbiComp). There are thus solutions such as frameworks, middlewares, and other development artifacts that come from the UbiComp community and can be used for IoT applications. On the other hand, the interaction evaluation of the applications can be more complex in IoT than in UbiComp systems, once we have two different perspectives: Human-Thing and Thing-Thing interactions. In this paper, based on the literature, our experience in these two domains, and case studies with Ubicomp and IoT applications, we discuss how we can benefit from the UbiComp move towards IoT, focusing on the main differences and similarities related to interaction evaluation. These differences open a set of questions that are also presented and discussed in this paper.\",\n \"Title: Recommendations for Usability Testing in Ubiquitous Applications\\nYear: 2016\\n\\nAbstract: Ubiquitous systems change the way users interact with computers, because their services must be available anytime and everywhere, supporting users in several everyday activities. Thus, there is a high risk of users feeling annoyed and overwhelmed by ubiquitous systems. It is, therefore, essential to evaluate the quality of use in those systems. One of the methods to perform this activity is the usability testing. However, the traditional process does not take into account specific characteristics from ubiquitous systems, for example context-awareness, transparency, attention, calmness, and mobility. This paper provides eight recommendations for usability testing in ubiquitous applications based on a literature review and on the authors experience with the evaluation of those systems.\",\n \"Title: Preventing Erosion in Exception Handling Design Using Static-Architecture Conformance Checking.\\nYear: 2017\\n\\nAbstract: Exception handling is a common error recovery technique employed to improve software robustness. However, studies have reported that exception handling is commonly neglected by developers and is the least understood and documented part of a software project. The lack of documentation and difficulty in understanding the exception handling design can lead developers to violate important design decisions, triggering an erosion process in the exception handling design. Architectural conformance checking provides means to control the architectural erosion by periodically checking if the actual architecture is consistent with the planned one. Nevertheless, available approaches do not provide a proper support for exception handling conformance checking. To fulfill this gap, we propose ArCatch: an architectural conformance checking solution to deal with the exception handling design erosion. ArCatch provides: (i) a declarative language for expressing design constraints regarding exception handling; and (ii) a design rule checker to automatically verify the exception handling conformance. To evaluate the usefulness and effectiveness of our approach, we conducted a case study, in which we evaluated an evolution scenario composed by 10 versions of an existing web-based Java system. Each version was checked against the same set of exception handling design rules. Based on the results and the feedback given by the system's architect, the ArCatch proved useful and effective in the identification of existing exception handling erosion problems and locating its causes in the source code.\",\n \"Title: Aggregating Measures using Fuzzy Logic for Evaluating Feature Models.\\nYear: 2018\\n\\nAbstract: In the context of Software Product Lines (SPLs), evaluating the quality of a feature model is essential to ensure that errors in the early stages do not spread throughout the SPL. One way to evaluate a feature model is to use measures. However, measures alone are not enough to characterize the feature model quality, because most of them cover specific aspects, such as the number of features. So, there is a need for methods to aggregate measures at the level of quality sub-characteristic or characteristic. In this paper, we aim to investigate how to aggregate measures that have been proposed to evaluate the quality of feature models in SPL. We have used the fuzzy logic theory in order to aggregate these measures. The new aggregated measures can be applied to evaluate different and complex aspects of a feature model, such as: size, stability, flexibility and dynamicity. Moreover, to evaluate the use of the new aggregate measures, we applied them in different feature models. Our findings suggest that aggregate measures can assist the domain engineer in evaluating the maintainability of feature models.\",\n \"Title: Towards a catalog of conflicts for HCI quality characteristics in UbiComp and IoT applications: Process and first results.\\nYear: 2018\\n\\nAbstract: Conflicts between non-functional requirements (NFRs) can happen when a particular solution favors the first NFR but creates difficulty for the second one. Usually, in the literature, the conflict identification uses catalogs to indicate conflicting NFRs. The authors focus on NFRs that are generic to any system. However, applications from Ubiquitous Computing (UbiComp) and Internet of Things (IoT) introduce new kind of NFRs (e.g., Context-Awareness and Mobility). They are not included in these catalogs and can impact the traditional ones (e.g., Security and Usability). Therefore, there is a need to create a catalog that considers conflicts among quality characteristics for UbiComp and IoT applications. However, the literature lacks a process or guideline about how to create a catalog. This paper aims then to present a process and initial findings towards a catalog of conflicts between specific HCI quality characteristics in UbiComp and IoT applications and Usability.\",\n \"Title: Bio-Inspired Model for Data Distribution in Fog and Mist Computing.\\nYear: 2018\\n\\nAbstract: Fog and Mist computing exploits computational resources of IoT devices located at the edge of the network. This new infrastructure brings benefits related to latency and Internet bandwidth utilization when compared with Cloud computing. However, this scenario is quite challenging mainly due to the considerable heterogeneity of the devices and to the dynamicity of the network topology what adds new issues related to security, privacy, data availability, and service availability, among others. Despite the theme of data dissemination and data storage had been relatively explored in fields of Sensor Wireless Network (WSN) and Vehicular Ad Hoc Networks (VANETs), we found few studies in the Fog computing research area. Then, this work focuses on the problem of data availability and dissemination in this environment by proposing a distributed algorithm using ideas from evolutionary computation and epidemic models. Results obtained through simulation suggest that the algorithm presents proper results in maintaining data availability in the Fog and Mist Computing environments, even under severe conditions.\",\n \"Title: Cloning In Customization Classes: A Case Of A Worldwide Software Product Line\\nYear: 2018\\n\\nAbstract: Cloning-and-owning, in the long run, can severely affect evolution, as changes in cloned fragments may require modifications in various parts of the system. This problem scales if cloning is used in classes that derive products in a Software Product Line, because these classes can impact in several features and products. However, it is hard to know to which extent cloning in customization classes can impact in a project. We conduct a study, within an SPL that generates mobile software for over 150 countries, to analyze cloning practices and how cloned parts relate to the maintainability of customization classes. We collect and identify clones inside customization classes during a period of 13 months, involving 70 customization classes and 5 branches. In parallel, we collect the respective issues from the issue tracking tool of the SPL project, obtaining over 140 issues related to customization classes. We then confront the time spent to solve each issue with its nature (i.e., if it relates to cloned code or not). As first result, we verify that issues related to cloning take in average 136% more time to be solved. Our study helps to understand how cloning relates to maintainability in the context of mass customization, giving insights about cloned code evolution and its impacts in a software product line project.\",\n \"Title: Catalog of Invisibility Requirements for UbiComp and IoT Applications\\nYear: 2018\\n\\nAbstract: A new set of Non-Functional Requirements (NFRs) have appeared with the advent of Ubiquitous Computing (UbiComp) and more recently Internet of Things (IoT). Invisibility is one of these NFRs that means the ability to hide technology from users. Although invisibility is long seen as an essential characteristic for achieving the goals of UbiComp, it has not been cataloged regarding its subcharacteristics and solutions, making its design and requirements specification in such applications a challenging task. Considering the Softgoal Interdependency Graph (SIG), which is a well-known format to catalog NFRs, this work aims at capturing subcharacteristics and solutions for Invisibility and cataloging them in a SIG. Since there is no systematic approach on how to build SIGs, we also propose to systematize the definition of Invisibility SIG using the following well-defined research methods: snowballing, database search, grounded theory and questionnaires. As a result, we got an Invisibility SIG composed of two main subcharacteristics, twelve sub-subcharacteristics, ten general solutions and fifty-six specific solutions. This organized body of knowledge is useful for supporting software engineers to specify requirements and practical solutions for UbiComp and IoT applications. Furthermore, the proposed methodology used to capture and catalog requirements in a SIG can be reused for other NFRs.\",\n \"Title: Correlations between invisibility and usability in ubicomp and IoT applications: partial results.\\nYear: 2018\\n\\nAbstract: Quality characteristics present several difficulties to be addressed. Negative correlations are one of these issues developers must deal during software development. These correlations mean that supporting a characteristic can negatively impact another one. A well-known solution to help developers identifying such correlations is through non-functional requirements (NFRs) catalogs. Although there are several correlations catalogs proposed in the literature, they do not take into account new characteristics that have arisen with the Ubiquitous Computing (UbiComp) and the Internet of Things (IoT) environment, such as Invisibility. In a previous study, a process for defining a catalog of correlations for quality characteristics was proposed. In this paper, we present partial results of the execution of this process for Invisibility and Usability. We also discuss some challenges regarding catalogs for quality characteristics.\",\n \"Title: Exploring quality measures for the evaluation of feature models: a case study.\\nYear: 2017\\n\\nAbstract: •We built a dataset that contains the values of 32 measures from COfFEE catalog.•We applied the Spearman’s rank to indicate the correlation between the 32 measures.•We grouped the measures by applying the PCA technique and defined 9 new measures.•We defined statistical thresholds for these 9 new grouped measures.\",\n \"Title: Heuristics To Evaluate The Usability Of Ubiquitous Systems\\nYear: 2017\\n\\nAbstract: While the ubiquitous systems have characteristics that modify the way the user interacts with the systems, Human-Computer Interaction area studies forms of interaction, with usability being one of the main quality criteria. One of the methods used to evaluate usability is Heuristic Evaluation. In the case of ubiquitous systems, that have characteristics such as mobility and context awareness, Nielsen's heuristics, which are widely used in conventional systems, do not focus on these particularities. Therefore, this work proposes specific heuristics to evaluate the usability of ubiquitous systems. Empirical studies and questionnaires were applied with experts in order to evaluate the proposed heuristics. The results point to improvements in both the way of conducting the evaluation and in the heuristics. From these results, the proposed heuristics were refined.\",\n \"Title: Mobile Audio Games Accessibility Evaluation For Users Who Are Blind\\nYear: 2017\\n\\nAbstract: Digital games have become increasingly popular for both entertainment and education purposes. However, making these games universal and accessible poses a challenge for interface designers and game developers, since they are usually unfamiliar with the peculiarities of gamers who are blind. More effort is necessary for contributing to a universal game design and, ultimately, helping to promote the inclusion of people with disabilities to take full advantages of digital games. In this research, we present a study concerning existent guidelines and recommendations for accessibility in digital games. As a result, we propose ten recommendations for the design of mobile audio games, targeting gamers who are blind. We also present an evaluation instrument assembled from the recommendations we propose. We used this instrument to assess ten audio games labeled as inclusive. Results indicate that only three from a total of ten games were considered \\\"good\\\", which means they met the fundamental aspects of the guidelines.\",\n \"Title: Issue Auto-Assignment in Software Projects with Machine Learning Techniques\\nYear: 2021\\n\\nAbstract: Usually, managers or technical leaders in software projects assign issues manually. This task may become more complex as more detailed is the issue description. This complexity can also make the process more prone to errors (misassignments) and time-consuming. In the literature, many studies aim to address this problem by using machine learning strategies. Although there is no specific solution th...\",\n \"Title: IoT-Health Platform to Monitor and Improve Quality of Life in Smart Environments\\nYear: 2021\\n\\nAbstract: Having a full and healthy life is what most people want. This involves a set of domains such as physical and psychological health, social relationships, and environmental issues. Together, these domains can be used to characterize a person's Quality of Life (QoL). This desire for a healthy life becomes even more prominent as the world population ages. Thereby, new socioeconomic challenges arise, putting pressure on governments and industries to adopt technologies to improve QoL. One of the technologies that have been widely used is the Internet of Health Things (IoHT). However, developers still face challenges when proposing IoHT solutions, such as lack of interoperability, high volatility, difficulties in providing runtime adaptations, high development cost when it involves AI, and the absence of a semantic model for QoL data. Thus, this Ph.D. project aims to investigate the development of QoL-based IoHT systems to address these challenges. As a result, an IoT-Health Platform is expected to support this development and bring health professionals closer to this process.\",\n \"Title: D-CreEA: DSML for Creating Educational Analog Card Games\\nYear: 2021\\n\\nAbstract: Educational games can promote a playful learning experience by solving problems related to the subject of a discipline and assign a student as the main actor in the learning process. In addition, when using analog educational games, this experience provides a face-to-face discussion on the subject, with tactile interaction and quick feedback. However, creating an educational game is difficult, bec...\",\n \"Title: Not the Same Everywhere: Comparing the Scope and Definition of User Experience between the Brazilian and International Communities\\nYear: 2022\\n\\nAbstract: The Human-Computer Interaction community worked over the last years on scoping and defining User Experience (UX). As reported in the literature, UX's understanding changes according to the socio-cultural context and between professional positions, making a global consensus unattainable. Nevertheless, tracking and investigating the most accepted UX definitions and statements may be advantageous for visualizing multiple contexts' needs. Such an investigation is still scarce and even more significant in developing countries since there are structural differences from developed countries in the software development industry that directly impact user research practices. To fill in this gap, we replicated in Brazil a survey distributed before, mostly among professionals from developed countries. We compared 252 responses from academics and practitioners and identified differences and similarities among Brazilian and international communities. The definitions of UX chosen by the academic and industrial domains explain differences in UX design and evaluation. When comparing Brazilians' responses with previous studies, Brazilians give greater importance to qualitative measures and to different UX time spans.\",\n \"Title: Performance Testing Guide for IoT Applications\\nYear: 2022\\n\\nAbstract: Internet of Things (IoT) applications are characterized by the use of smart objects that are connected to the Internet to provide different types of services. These objects usually generate data that need to be stored and analyzed to contribute to decision making (whether or not they are immediate). In this context, such applications may require high performance, low cost and good scalability. These requirements bring new testing challenges and the need for specific approaches, for example, the detection of performance failures among heterogeneous IoT devices, which process a large amount of data and, under uncertain conditions, must have their resources optimized. Thus, our goal is to propose a performance testing guide for the evaluation of IoT applications. To build the guide, we performed a literature review to identify the IoT standards and analyzed IoT bug repositories. In this paper, we present the Performance Testing Guide for IoT applications. To validate the proposed guide, we conducted two evaluations: (i) an evaluation with the experts; and (ii) a controlled experiment. The results showed that the guide provides a systematization of testing activities, helping the evaluation of IoT aspects intrinsic to performance.\",\n \"Title: Where Is the Internet of Health Things Data?\\nYear: 2022\\n\\nAbstract: The advent of Internet of Things (IoT) and the smart objects popularization have boosted the data generation in many areas. Data have then become increasingly valuable as they can be used to \\\"teach\\\" machines to perform the most varied tasks. Health is among the areas that have benefited from such data, because there is, for example, a need for solutions that optimize the cost-benefit ratio of health systems. In this scenario, the Internet of Health Things (IoHT) uses smart sensors to collect patient data and intelligent algorithms to process this data for improving patient Quality of Life. However, researchers and practitioners have faced difficulties in finding and using public health care data sensor repositories. Therefore, we conducted a systematic multivocal review of IoHT databases to identify and characterize the existing datasets. We also bring as a contribution of this paper a set of guidelines about how new IoHT data repositories can be structured.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":85,"string":"85"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13358,"string":"13,358"}}},{"rowIdx":13359,"cells":{"question_id":{"kind":"string","value":"Elisabeth Andr"},"question":{"kind":"string","value":"Generate an abstract for the title \"The PPP persona: a multipurpose animated presentation agent\" using the following items: Animated Agents, PPP Persona, Presentation Tasks, Client/Server Paradigm, User Interaction."},"answer":{"kind":"string","value":"Animated agents - either based on real video, cartoon-style drawings or even model-based 3D graphics are likely to become integral parts of future user interfaces. We present the PPP Persona, a tool which can be used for showing, explaining, and verbally commenting textual and graphical output on a window-based interface. The realization of the module follows the client/server paradigm, i.e, some client applications can send requests for executing presentation tasks to the server. However, to achieve a lively and appealing behaviour of the animated agent, the server autonomously performs some actions, eg. to span pauses or to react immediately to user interactions."},"correct_answer":{"kind":"string","value":"Animated agents - either based on real video, cartoon-style drawings or even model-based 3D graphics are likely to become integral parts of future user interfaces. We present the PPP Persona, a tool which can be used for showing, explaining, and verbally commenting textual and graphical output on a window-based interface. The realization of the module follows the client/server paradigm, i.e, some client applications can send requests for executing presentation tasks to the server. However, to achieve a lively and appealing behaviour of the animated agent, the server autonomously performs some actions, eg. to span pauses or to react immediately to user interactions."},"documents":{"kind":"list like","value":["Title: Tool-Supported User-Centred Prototyping of Mobile Applications\nYear: 2011\n\nAbstract: There is evidence that user-centred development increases the user-friendliness of resulting products and thus the distinguishing features compared to products of competitors. However, the user-centred development requires comprehensive software and usability engineering skills to keep the process both cost-effective and time-effective. This paper covers that problem and provides insights in so-called user-centred prototyping UCP tools which support the production of prototypes as well as their evaluation with end-users. In particular, UCP tool called MoPeDT Pervasive Interface Development Toolkit for Mobile Phones is introduced. It provides assistance to interface developers of applications where mobile phones are used as interaction devices to a user's everyday pervasive environment. Based on found tool features for UCP tools, a feature study is described between related tools and MoPeDT as well as a comparative user study between this tool and a traditional approach. A further focus of the paper is the tool-supported execution of empiric evaluations.","Title: Exploration of user reactions to different dialog-based interaction styles\nYear: 2011\n\nAbstract: How human users perceive and interact with interactive story-telling applications has not been widely researched so far. In this paper, we present an experimental approach in which we investigate the impact of different dialog-based interaction styles on human users. To this end, an interactive demonstrator has been evaluated in two different versions: one providing a continuous interaction style where interaction is possible at any time, and another providing system-initiated interaction where the user can only interact at certain prompts.","Title: From Physiological Signals To Emotions: Implementing And Comparing Selected Methods For Feature Extraction And Classification\nYear: 2005\n\nAbstract: Little attention has been paid so far to physiological signals for emotion recognition compared to audio-visual emotion channels, such as facial expressions or speech. In this paper, we discuss the most important stages of a fully implemented emotion recognition system including data analysis and classification. For collecting physiological signals in different affective states, We used a music induction method which elicits natural emotional reactions from the subject.. Four-channel biosensors are used to obtain electromyogram, electrocardiogram, skin conductivity and respiration changes. After calculating a sufficient amount of features from the raw signals, several feature selection/reduction methods are tested to extract a new feature set consisting of the most significant features for improving classification performance. Three well-known classifiers, linear discriminant function, k-nearest neighbour and multilayer perceptron, are then used to perform supervised classification.","Title: Trustworthy organic computing systems: challenges and perspectives\nYear: 2010\n\nAbstract: Organic Computing (OC) systems differ from classical software systems as the topology and the participating components of the system are not predefined and therefore are subject to unforeseeable change during the systems' runtime. Thus, completely new challenges to the verification and validation of such systems as well as for interactions between system components and, of course, between the system and the user arise. These challenges can be subsumed by the terms trustworthiness or trust. This paper proposes - after exploring the notions and principles of trust in the literature - a definition of trust which encompasses all aspects that define the trustworthiness of an Organic Computing system. It then outlines the different research challenges that have to be tackled in order to provide an understanding of trust in OC-systems and gives perspectives on how this endeavour can be taken on. Current research initiatives in the area of trust in computing systems are reviewed and discussed.","Title: A data-driven approach to model culture-specific communication management styles for virtual agents\nYear: 2010\n\nAbstract: Virtual agents are a great opportunity in teaching inter-cultural competencies. Advantages, such as the repeatability of training sessions, emotional distance to virtual characters, the opportunity to over-exaggerate or generalize behavior or simply to save the costs for human training-partners support that idea. Especially the way communication is coordinated varies across cultures. In this paper, we present our approach of simulating differences in the management of communication for the American and Arabic cultures. Therefore, we give an overview of behavioral tendencies described in the literature, pointing out differences between the two cultures. Grounding our expectations in empirical data we analyzed a multi-modal corpora. These findings were integrated into a demonstrator using virtual agents and evaluated in a preliminary study.","Title: From adaptive hypertext to personalized web companions\nYear: 2002\n\nAbstract: The advent of Web browsers able to execute programs embedded in Web pages has enabled the use of embodied conversational characters on the Internet. In fact, an increasing number of Web sites employ animated characters for a large variety of tasks: virtual teachers guide users through online learning activities [6], Web chauffeurs provide recommendations on which links to follow, and virtual insurance agents help users to fill in forms. Web-based sales agents do not just present the customer with various products, but try to make the visit to an online store a unique experience; see [5] for an overview. Companies, such as Artificial Life, Extempo, Haptek, and Virtual Personalities,(1) create virtual characters specifically for the Internet.","Title: Multimodal interaction with a virtual character in interactive storytelling\nYear: 2010\n\nAbstract: A number of interactive storytelling (IS) systems offer the user the possibility to input natural language input which determines how a story progresses. We introduce a framework for real-time signal processing (SSI) to analyze the users' state which then can influence the feelings of the story characters and their actions in the story. SSI is not only used to enable more natural character responses that are sensitive to the user's state at runtime. In addition SSI offers the possibility to collect a large variety of synchronized user data which can be used to analyze the user's experience in offline mode. The underlying narrative in which the approach was tested is based on a classical XIXth century psychological novel: Madame Bovary, by Flaubert.","Title: Level of detail AI for virtual characters in games and simulation\nYear: 2010\n\nAbstract: Following recent research that takes the idea of Level of Detail (LOD) from its traditional use in 3D graphics and applies it to the artificial intelligence (AI) of virtual characters, we propose our approach on such an LOD AI. We describe how our approach handles LOD classification and how we used it to simplify the simulation quality of multiple aspects of the characters' behavior in an existing application. Finally, we delineate how we evaluated our approach with both a performance and perception analysis and report our findings.","Title: The TARDIS Framework: Intelligent Virtual Agents for Social Coaching in Job Interviews\nYear: 2013\n\nAbstract: The TARDIS project aims to build a scenario-based serious-game simulation platform for NEETs and job-inclusion associations that supports social training and coaching in the context of job interviews. This paper presents the general architecture of the TARDIS job interview simulator, and the serious game paradigm that we are developing.","Title: Building smart embodied virtual characters\nYear: 2003\n\nAbstract: Embodied conversational characters are autonomous, graphically embodied virtual creatures that live in a 2D or 3D virtual environment. They are able to interact intelligently with human users, other characters, and their digital environment. While for decades research has concentrated on geometric body modelling and the development of animation and rendering techniques for virtual characters, other qualities have now come in focus as well, including the provision of conversational skills as well as the simulation of believable behavior including affect and peculiarities induced by individual personality traits. As a consequence, the domain of virtual characters has become much more diverse and now encompasses a wide range of disciplines, from computer graphics and animation to AI and more recently also psychology, sociology as well as design and arts. The current paper discusses a number of design issues that arise when building an application with one or more embodied characters. By means of selected sample applications we also illustrate a yet ongoing development of animated presentation agents starting with TV-style information presenters to highly interactive multi-character scenarios in which information is conveyed to the user in the form of multi-party conversations.","Title: Some Pitfalls for Developing Enculturated Conversational Agents\nYear: 2009\n\nAbstract: A review of current agent-based systems exemplifies that a Western perspective is predominant in the field. But as conversational agents focus on rich multimodal interactive behaviors that underlie face-to-face encounters, it is indispensable to incorporate cultural heuristics of such behaviors into the system. In this paper we examine some of the pitfalls that arise in developing such systems.","Title: MoPeDT: features and evaluation of a user-centred prototyping tool\nYear: 2010\n\nAbstract: User-Centred Prototyping (UCP) tools are expected to support interface developers in order to more efficiently, effectively and satisfactorily design, evaluate and analyse user-friendly products by an all-in-one tool solution. We developed such a UCP tool called MoPeDT that supports the user-centred development of interactive evolutionary prototypes for mobile phones in the context of the Internet of Things. In this paper we address our tool features for the design, evaluation and analysis phase that mostly base on meaningful features from related tools. Additionally, we cover potential enhancements to former UCP tools in order to support interface developers with a wide-ranging playground to investigate the user's behaviour and preferences. The paper also describes MoPeDT's evaluation with 20 students over one month that investigated the interface developer's efficiency, effectiveness and satisfaction when applying our UCP tool. As an outcome of this study we describe potential benefits and problems that might be of interest to other developers of UCP tools.","Title: Trust-based decision-making for the adaptation of public displays in changing social contexts.\nYear: 2013\n\nAbstract: Public displays may adapt intelligently to the social context, tailoring information on the screen, for example, to the profiles of spectators, their gender or based on their mutual proximity. However, such adaptation decisions should on the one hand match user preferences and on the other maintain the user's trust in the system. A wrong decision can negatively influence the user's acceptance of a system, cause frustration and, as a result, make users abandon the system. In this paper, we propose a trust-based mechanism for automatic decision-making, which is based on Bayesian Networks. We present the process of network construction, initialization with empirical data, and validation. The validation demonstrates that the mechanism generates accurate decisions on adaptation which match user preferences and support user trust.","Title: A plug-and-play framework for theories of social group dynamics\nYear: 2006\n\nAbstract: We present an extensible framework for behavior control of social agents in a multi-agent system that has the following features. It implements a basic repertoire of socio-psychological models of behavior and interpersonal interactions that can be plugged and unplugged at will depending on the specific context of the application. This enables us to test several theories in isolation or combination to increase the transparency of the system and to investigate how the inclusion of a certain theory influences the behavior of the agents. Unlike earlier approaches, our approach is not bound to a specific theory. Thus, it becomes possible to run a simulation with the same set of agents using different theories to compare their effect.","Title: Generating coherent presentations employing textual and visual material\nYear: 1995\n\nAbstract: The objective of the work described in this paper is the development of an intelligent generation system which is able to combine textual and visual material. As coherent presentations cannot be generated by simply merging verbalization and visualization results into multimedia output, the processes for content determination, medium selection and content realization in different media have to be carefully coordinated. We first show that multimedia presentations and pure text follow similar structuring principles. Based on this insight, we sketch how techniques for planning text and discourse can be generalized to allow the structure and contents of multimedia communications to be planned as well. In particular, we explain how our approach handles the crucial task of process coordination.","Title: Studies on grounding with gaze and pointing gestures in human-robot-interaction\nYear: 2012\n\nAbstract: In this study we investigated the use of gaze and pointing gestures in scenarios where a human has to follow the instructions of a humanoid robot. Our objective was to analyze the performance of a human participant, that solves an abstract jigsaw puzzle with the help of our robot instructor, in different grounding scenarios with varying difficulty. Furthermore we investigated how the attitude towards the robot and the self-assessment of the participant changed. Our results support that adding gaze to the interaction usually improves the interaction, but often additional pointing gestures are needed to make a significant difference.","Title: Trust-centered design for multi-display applications\nYear: 2010\n\nAbstract: This work describes a trust-centered user study that was conducted during the design process of a multi-display ubiquitous application. The objective of the study was to find out how the adaptation of the displays should be designed in order to protect user trust. The study was conducted in the form of focus group interviews; it investigated user attitude towards data and events that can be seen as trust-critical in a multi-display interaction scenario. The quantitative results, along with user comments and discussions, provide an interesting insight how the system should be adapted in order to preserve user trust.","Title: An immersive game – augsburg cityrun\nYear: 2006\n\nAbstract: We present a platform for creating immersive 3D games including a new interface for navigating through virtual scenes. One innovative part of this application is a crowd simulation with an emergent behaviour of virtual characters. While the users has to move very quickly through a crowd of nearly two hundred virtual characters he is supported by a precise, fast operating, and unobtrusive navigation interface.","Title: Simplified facial animation control utilizing novel input devices: a comparative study\nYear: 2009\n\nAbstract: Editing facial expressions of virtual characters is quite a complex task. The face is made up of many muscles, which are partly activated concurrently. Virtual faces with human expressiveness are usually designed with a limited amount of facial regulators. Such regulators are derived from the facial muscle parts that are concurrently activated. Common tools for editing such facial expressions use slider-based interfaces where only a single input at a time is possible. Novel input devices, such as gamepads or data gloves, which allow parallel editing, could not only speed up editing, but also simplify the composition of new facial expressions. We created a virtual face with 23 facial controls and connected it with a slider-based GUI, a gamepad, and a data glove. We first conducted a survey with professional graphics designers to find out how the latter two new input devices would be received in a commercial context. A second comparative study with 17 subjects was conducted to analyze the performance and quality of these two new input devices using subjective and objective measurements.","Title: Integrating models of personality and emotions into lifelike characters\nYear: 1999\n\nAbstract: Abstract. A growing ,number ,of research ,projects in academia ,and industry have recently started to develop ,lifelike agents as a ,new ,metaphor ,for highly personalised human-machine ,communication. ,A strong argument ,in favour ,of using such characters in the ,interface is the ,fact that they make ,humancomputer,interaction more ,enjoyable ,and ,allow for communication ,styles common,in human-human ,dialogue. Our earlier work ,in this ,area has concentrated on the development of animated presenters that show, explain, and verbally comment ,textual and graphical output on a ,window-based ,interface. Even though first empirical studies have been very encouraging,and revealed a strong affective impact of our Personas [23], they also suggest that simply embodying an interface agent is insufficient. To come across as believable, an agent needs to incorporate a deeper model of personality and emotions, and in particular directly connect these two concepts.","Title: Intellimedia: making multimedia usable by exploiting AI methods\nYear: 1995\n\nAbstract: This paper sketches how we integrated multiple AI methods, such as planning, constraintprocessing, temporal reasoning, natural processing processing and knowledge representation,into the presentations systems WIP and PPP.","Title: Composing Affective Music with a Generate and Sense Approach\nYear: 2004\n\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user- specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.","Title: Smart Sensor Integration: A Framework for Multimodal Emotion Recognition in Real-Time\nYear: 2009\n\nAbstract: Affect sensing by machines has been argued as an es- sential part of next-generation human-computer interaction (HCI). To this end, in the recent years a large number of studies have been conducted, which report automatic recog- nition of emotion as a difficult, but feasible task. However, most effort has been put towards offline analysis, whereas to date only few applications exist, which are able to react to a user's emotion in real-time. In response to this deficit we introduce a framework we call Smart Sensor Integra- tion (SSI), which considerably jump-starts the development of multimodal online emotion recognition (OER) systems. In particular SSI supports the pattern recognition pipeline by offering tailored tools for data segmentation, feature ex- traction, and pattern recognition, as well as, tools to apply them offline (training phase) and online (real-time recog- nition). Furthermore, it has been designed to handle input from various input modalities and to suit the fusion of mul- timodal information.","Title: Augmented reality using a 3D motion capturing suit\nYear: 2013\n\nAbstract: In the paper, we propose an approach that immerses the human user in an Augmented Reality (AR) environment with the use of an inertial motion capturing suit and a Head Mounted Displays system. The proposed approach allows for full body interaction with the AR environment in real-time and it does not require the use of any markers or cameras.","Title: A sensing architecture for empathetic data systems\nYear: 2013\n\nAbstract: Today's increasingly large and complex databases require novel and machine aided ways of exploring data. To optimize the selection and presentation of data, we suggest an unconventional approach. Instead of exclusively relying on explicit user input to specify relevant information or to navigate through a data space, we exploit the power and potential of the users' unconscious processes in addition. To this end, the user is immersed in a mixed reality environment while his bodily reactions are captured using unobtrusive wearable devices. The users' reactions are analyzed in real-time and mapped onto higher-level psychological states, such as surprise or boredom, in order to trigger appropriate system responses that direct the users' attention to areas of potential interest in the visualizations. The realization of such a close experience-based human-machine loop raises a number of technical challenges, such as the real-time interpretation of psychological user states. The paper at hand describes a sensing architecture for empathetic data systems that has been developed as part of such a loop and how it tackles the diverse challenges.","Title: A Systematic Comparison of Different HMM Designs for Emotion Recognition from Acted and Spontaneous Speech\nYear: 2007\n\nAbstract: In this work we elaborate the use of hidden Markov models (HMMs) for speech emotion recognition as a dynamic alternative to static modelling approaches. Since previous work on this field does not yet define a clear line which HMM design should be prioritised for this task, we run a systematic analysis of different HMM configurations. Furthermore, experiments are carried out on an acted and a spontaneous emotions corpus, since little is known about the suitability of HMMs for spontaneous speech. Additionally, we consider two different segmentation levels, namely words and utterances. Results are compared with the outcome of a support vector machine classifier trained on global statistics features. While for both databases similar performance was observed on utterance level, the HMM-based approach outperformed static classification on word level. However, setting up general guidelines which kind of models are best suited appeared to be rather difficult.","Title: Combining Alternatives in the Multimedia presentation of Decision Support Information for Real-Time Control\nYear: 1998\n\nAbstract: Multimedia technology is emerging as a key element in the area of Decision Sup- port Systems (DSS) since well-designed multimedia presentations help the human decision maker to assimilate relevant information more easily. The use of multiple media, however, increases the complexity of the presentation design task. Especially when complex information structures have to be presented under time pressuread hoc' solutions to presentation generation are getting more and more impractical, if not impossible to use. In this paper we report on our approach to enhance a DSS for real-time traffic management with an advanced component for the automated gener- ation of multimedia presentations. A common problem in this application class is the presentation of alternatives such as different explanations or predictions for a current traffic situation, or different sequences of control actions which may be initiated to resolve a problem. We describe a novel approach to provide aggregated information presentations rather than presenting alternatives just one after the other.","Title: Generating culture-specific gestures for virtual agent dialogs\nYear: 2010\n\nAbstract: Integrating culture into the behavioral model of virtual agents has come into focus lately. When investigating verbal aspects of behavior, nonverbal behaviors are desirably added automatically, driven by the speech-act. In this paper, we present a corpus driven approach of generating gestures in a culture-specific way that accompany agent dialogs. The frequency of gestures and gesture-types, the correlation of gesture-types and speech-acts as well as the expressivity of gestures have been analyzed in the two cultures of Germany and Japan and integrated into a demonstrator.","Title: Creating and Scripting Second Life Bots Using MPML3D\nYear: 2008\n\nAbstract: The use of virtual characters becomes invariably common in computer games and other applications. So-called \"bots\" (computer-controlled virtual characters), may explain virtual settings in a natural way. We describe an example scenario in the online world Second Life [1] in order to explain to content creators how to create bots and script their behavior using the well established authoring language MPML3D [2]. MPML3D does not assume knowledge of a high-level programming language. In Second Life users are represented by their avatars (virtual characters controlled by humans) and its environment provides character models, animations and a graphics engine.","Title: From annotated multimodal corpora to simulated human-like behaviors\nYear: 2006\n\nAbstract: Multimodal corpora prove useful at different stages of the development process of embodied conversational agents. Insights into human-human communicative behaviors can be drawn from such corpora. Rules for planning and generating such behavior in agents can be derived from this information. And even the evaluation of human-agent interactions can rely on corpus data from human-human communication. In this paper, we exemplify how corpora can be exploited at the different development steps, starting with the question of how corpora are annotated and on what level of granularity. The corpus data can be used either directly for imitating the human behavior recorded in the corpus or rules can be derived from the data which govern the behavior planning process. Corpora can even play a vital role in the evaluation of agent systems. Several studies are presented that make use of corpora for the evaluation task.","Title: WIP and PPP: a comparison of two multimedia presentation systems in terms of the standard reference model\nYear: 1997\n\nAbstract: In this paper, the Standard Reference Model for IMMPS is used for analysing the architectural design of two multimedia presentation systems which have been built at DFKI over the past 10 years. We first present the systems as described by the authors and then compare them in terms of the reference model. (C) 1997 Elsevier Science B.V.","Title: Adding Life-Like Synthetic Characters to the Web\nYear: 2000\n\nAbstract: With the advent of web browsers that are able to execute programs embedded in web pages, the use of animated characters for\n the presentation of information over the web has become possible. A strong argument in favour of using such characters in\n a web interface is the fact that they make human-computer interaction more enjoyable and allow for the emulation of communication\n styles common in human-human dialogue. In this paper we discuss three ongoing DFKI projects on life-like synthetic characters\n in the internet. While all agents rely on the same approach for automated script generation, we use different player technologies\n which will be discussed in the light of different applications.","Title: Endowing Spoken Language Dialogue Systems with Emotional Intelligence\nYear: 2004\n\nAbstract: While most dialogue systems restrict themselves to the adjustment of the propositional contents, Pur work concentrates on the generation of stylistic variations in order to improve the user's perception of the interaction. To accomplish this goal, our approach integrates a social theory of politeness with a cognitive theory of, emotions. We propose a hierarchical selection process for politeness behaviors in order to enable the refinement of decisions in case additional context information becomes available.","Title: Role assignment via physical mobile interaction techniques in mobile multi-user applications for children\nYear: 2007\n\nAbstract: The development of engaging user interfaces that support collaboration is a great challenge - in particular if users are children. We consider mobile phones as appropriate devices for multi-user interactions with a system because novel forms of physical mobile interaction techniques with smart objects yield lots of benefits, such as being intuitive and playful to use, but also addressing children's needs for curiosity. In this paper, we introduce our approach to multi-user game-like scenarios within an ambient intelligence context which are controlled via different mobile phones and their supported interaction techniques. By providing children with multiple mobile phones we structure interactions in multi-user settings and prevent undesirable situations, such as dominant users or off-topic actions. Children get access to various physical mobile interaction techniques for interactions with smart objects which are all required to fulfill one common goal. In this way, social interaction arises in a natural manner. In order to motivate and evaluate our approach, we developed two ambient intelligence applications called The World Explorer and The Escape. Results of a user study showed that children liked working in a group and that physical mobile interaction techniques are a promising approach to increase engagement and foster social interactions but also to prevent chaotic situations by balancing the distribution of activities in multi-user settings.","Title: Workshop: eye gaze in intelligent human machine interaction\nYear: 2010\n\nAbstract: This workshop brought researchers from academia and industry together to share recent advances and discuss research directions and opportunities for next generation of intelligent human machine interaction that incorporate eye gaze.","Title: To see and to be seen in the virtual beer garden: a gaze behavior system for intelligent virtual agents in a 3D environment\nYear: 2009\n\nAbstract: Aiming to increase the believability of intelligent virtual agents, this paper describes the implementation of a parameterizable gaze behavior system based on psychological notions of human gaze. The resulting gaze patterns and agent behaviors cover a wide range of possible uses due to this parametrization. We also show how we integrated and used the system within a virtual environment.","Title: Interpreting social cues to generate credible affective reactions of virtual job interviewers.\nYear: 2014\n\nAbstract: In this paper we describe a mechanism of generating credible affective reactions in a virtual recruiter during an interaction with a user. This is done using communicative performance computation based on the behaviours of the user as detected by a recognition module. The proposed software pipeline is part of the TARDIS system which aims to aid young job seekers in acquiring job interview related social skills. In this context, our system enables the virtual recruiter to realistically adapt and react to the user in real-time.","Title: Introduction to the special issue on eye gaze in intelligent human-machine interaction\nYear: 2012\n\nAbstract: Given the recent advances in eye tracking technology and the availability of nonintrusive and high-performance eye tracking devices, there has never been a better time to explore new opportunities to incorporate eye gaze in intelligent and natural human-machine communication. In this special issue, we present six articles that cover various aspects of eye gaze in human-machine interaction, including applications of gaze tracking in human-machine interaction, techniques that recognize gaze gestures and render gaze behaviors, and the analysis of gaze behaviors in social interactions.","Title: Increasing learners' motivation through pedagogical agents: the cast of virtual characters in the dynalearn ILE\nYear: 2011\n\nAbstract: Motivation is a critical requirement for successful learning. Previous research has identified that animated pedagogical agents can increase motivation. Following these results, we present the cast of pedagogical agents in the DynaLearn Intelligent Learning Environment. Each of these agents is associated with one of the different support types available in the environment, giving each agent a clearly defined role. We describe the different character roles, how their knowledge is generated and related to the pedagogical purpose at hand, how they interact with the learners and finally how this interaction helps increasing the learners' motivation. To assess this, we conducted a preliminary evaluation with three of the characters and report our findings.","Title: Avatar culture: cross-cultural evaluations of avatar facial expressions\nYear: 2009\n\nAbstract: Avatars are increasingly used to express our emotions in our online communications. Such avatars are used based on the assumption that avatar expressions are interpreted universally among all cultures. This paper investigated cross-cultural evaluations of avatar expressions designed by Japanese and Western designers. The goals of the study were: (1) to investigate cultural differences in avatar expression evaluation and apply findings from psychological studies of human facial expression recognition, (2) to identify expressions and design features that cause cultural differences in avatar facial expression interpretation. The results of our study confirmed that (1) there are cultural differences in interpreting avatars’ facial expressions, and the psychological theory that suggests physical proximity affects facial expression recognition accuracy is also applicable to avatar facial expressions, (2) positive expressions have wider cultural variance in interpretation than negative ones, (3) use of gestures and gesture marks may sometimes cause counter-effects in recognizing avatar facial expressions.","Title: Using the mobile application EDDY for gathering user information in the requirement analysis\nYear: 2010\n\nAbstract: The users' knowledge and requirements are important factors in the design of products. To ensure the success of products designers and developers have to get to know their target group users better. Over the years a lot of innovative user centered design studies have been written. Many researchers believe that these studies could be used by developers to help them in the process of creating new products. This paper presents a framework called EDDY that aims at facilitating the development of mobile applications for gathering various kinds of data. Such a framework and applications based on it should be helpful for the data collection during studies such as Cultural Probes and the Experience Sampling Method. These approaches involve the users as the persons who collect the required information themselves. In this paper we evaluate the advantages of EDDY for such studies. We investigated whether there is a significant advantage in using a mobile application for the documentation of a user's everyday life instead of using a classical kit.","Title: Knowledge-Based Generation of Illustrated Documents\nYear: 1991\n\nAbstract: The task of the knowledge-based presentation system WIP is the generation of a variety of multimodal documents from an input consisting of a formal description of the communicative intent of a planned presentation. WIP generates illustrated texts that are customized for the intended audience and situation. We present the architecture of WIP and introduce as its major components the presentation planner, the layout manager, the text generator and the graphics generator. An extended notion of coherence for multimodal documents is introduced that can be used to constrain the presentation planning process. The paper focuses on the coordination of contents planning and layout that is necessary to produce a coherent illustrated text. In particular, we discuss layout revisions after contents planning and the influence of layout constraints on text generation. We show that in WIP the design of a multimodal document is viewed as a non-monotonic planning process that includes various revisions of preliminary results in order to achieve a coherent output with an optimal media mix.","Title: Bossy or wimpy: expressing social dominance by combining gaze and linguistic behaviors\nYear: 2010\n\nAbstract: This paper examines the interaction of verbal and nonverbal information for conveying social dominance in intelligent virtual agents (IVAs). We expect expressing social dominance to be useful in applications related to persuasion and motivation; here we simply test whether we can affect users' perceptions of social dominance using procedurally generated conversational behavior. Our results replicate previous results showing that gaze behaviors affect dominance perceptions, as well as providing new results showing that, in our experiments, the linguistic expression of disagreeableness has a significant effect on dominance perceptions, but that extraversion does not.","Title: Integrating information from speech and physiological signals to achieve emotional sensitivity\nYear: 2005\n\nAbstract: Recently, there has been a significant amount of work on the recognition of emotions from speech and biosignals. Most approaches toemotion recognition so farconcentrate on asingle modality and do not take advantage of the fact that an integrated multimodal analysis may help to resolve ambiguities and com- pensate for errors. In this paper, we describe various methods for fusing physiological and voice data at the feature-level and the decision-level as well as a hybrid integration scheme. The resultsof the integrated recognition approach arethen compared with the individual recognition results from each modality.","Title: Exploring The Benefits Of Discretization Of Acoustic Features For Speech Emotion Recognition\nYear: 2009\n\nAbstract: We present a contribution to the Open Performance sub-challenge of the INTERSPEECH 2009 Emotion Challenge. We evaluate the feature extraction and classifier of EmoVoice, our framework for real-time emotion recognition from voice on the challenge database and achieve competitive results. Furthermore, we explore the benefits of discretizing numeric acoustic features and find it beneficial in a multi-class task.","Title: From Simulated Dialogues to Interactive Performances\nYear: 2001\n\nAbstract: In this contribution, we argue in favor of a shift from applications with single presentation agents towards flexible performances given by a team of characters as a new presentation style. We will illustrate our approach by means of two subsequent versions of a test-bed called the \"Inhabited Market Place\" (IMP1 and IMP2). In IMP1, the attribute \"flexible\" refers to the system's ability to adapt a presentation to the needs and preferences of a particular user. In IMP2, flexibility additionally refers to the user's option of actively participating in a computer-based performance and influencing the behavior of the involved characters at runtime. While a plan-based approach has proven appropriate in both versions to automatically control the behavior of the agents, IMP2 calls for highly reactive and distributed behavior planning.","Title: Visual communication in interactive multimedia\nYear: 2011\n\nAbstract: Careful selection of graphical design can push the narrative strength of graphical projects by adjusting the visual statements to the content-wise statements. While many projects of computer science lack of consequent implementation of artistic principles, graphic designers tend to neglect user interaction and evaluation. In a recent project we therefore started a successful approach to combine both sides. In future work we plan to research on further integration of visual narration into interactive storytelling.","Title: Four-Channel Biosignal Analysis and Feature Extraction for Automatic Emotion Recognition\nYear: 2008\n\nAbstract: This paper investigates the potential of physiological signals as a reliable channel for automatic recognition of user's emotial state. For the emotion recognition, little attention has been paid so far to physiological signals compared to audio-visual emotion channels such as facial expression or speech. All essential stages of automatic recognition system using biosignals are discussed, from recording physiological dataset up to feature-based multiclass classification. Four-channel biosensors are used to measure electromyogram, electrocardiogram, skin conductivity and respiration changes. A wide range of physiological features from various analysis domains, including time/frequency, entropy, geometric analysis, subband spectra, multiscale entropy, etc., is proposed in order to search the best emotion-relevant features and to correlate them with emotional states. The best features extracted are specified in detail and their effectiveness is proven by emotion recognition results.","Title: Werewolves, cheats, and cultural sensitivity\nYear: 2014\n\nAbstract: MIXER (Moderating Interactions for Cross-Cultural Empathic Relationships), which applies a novel approach to the education of children in cultural sensitivity. MIXER incorporates intelligent affective and interactive characters, including a model of a Theory of Mind mechanism, in a simulated virtual world. We discuss the relevant pedagogical approaches, related work, the underlying mind model used for MIXER agents as well as its innovative interaction interface utilising a tablet computer and a pictorial interaction language. We then consider the evaluation of the system, whether this shows it met its pedagogical objectives, and what can be learned from our results.","Title: A flexible platform for building applications with life-like characters\nYear: 2003\n\nAbstract: During the last years, an increasing number of R&D projects has started to deploy life-like characters for presentation tasks in a diverse range of application areas, including, for example, E-Commerce, E-learning, and help systems. Depending on factors, such as the degree of interactivity and the number of the deployed characters, different architectures have been proposed for system implementation. In this contribution, we first analyse a number of existing user interfaces with presentation characters from an architectural point of view. We then introduce the MIAU platform and illustrate by means of illustrated generation examples how MIAU can be used for the realization of character applications with different conversational settings. Finally, we sketch a number of potential application fields for the MIAU platform","Title: Comparing Feature Sets For Acted And Spontaneous Speech In View Of Automatic Emotion Recognition\nYear: 2005\n\nAbstract: We present a data-mining experiment on feature selection for automatic emotion recognition. Starting from more than 1000 features derived from pitch, energy and MFCC time series, the most relevant features in respect to the data are selected from this set by removing correlated features. The features selected for acted and realistic emotions are analysed and show significant differences. All features are computed automatically and we also contrast automatically with manually units of analysis. A higher degree of automation did not prove to be a disadvantage in terms of recognition accuracy.","Title: Modeling multimodal integration with event logic charts\nYear: 2012\n\nAbstract: In this paper we present a novel approach to the combined modeling of multimodal fusion and interaction management. The approach is based on a declarative multimodal event logic that allows the integration of inputs distributed over multiple modalities in accordance to spatial, temporal and semantic constraints. In conjunction with a visual state chart language, our approach supports the incremental parsing and fusion of inputs and a tight coupling with interaction management. The incremental and parallel parsing approach allows us to cope with concurrent continuous and discrete interactions and fusion on different levels of abstraction. The high-level visual and declarative modeling methods support rapid prototyping and iterative development of multimodal systems.","Title: Integrating a Virtual Agent into the Real World: The Virtual Anatomy Assistant Ritchie\nYear: 2007\n\nAbstract: Augmented realities, which are partially real and partially virtual, open up new ways for humans to interact with Embodied Conversational Agents (ECAs) since they allow users to meet ECAs in the physical space. Nevertheless, attempts to integrate ECAs as digital overlays in a physical space have been rare. Obvious reasons are the high demands such an integration puts to the animation of ECAs as virtual augmentations of the physical space, their capabilities to perceive not only the virtual, but also the physical world as well as reactive behavior control. In this paper, we describe our technical contributions towards solving these challenges. To illustrate our ideas, we present the virtual anatomy assistant Ritchie that monitors the user's actions in a physical space and dynamically responds to them.","Title: Introducing Multiple Interaction Devices to Interactive Storytelling: Experiences from Practice\nYear: 2009\n\nAbstract: Introducing multiple interaction devices into an interactive story provides certain advantages to the system: it fosters collaboration in multi-user settings, increases user involvement, and addresses more perception channels and user senses. It is a challenging task for designers to introduce multiple interaction devices into an interactive storytelling (IS) system. In this paper we report on our experiences with the design and evaluation of an IS system, called ORIENT. The system was created for multi-user settings; it embeds various interaction devices, such as mobile phones, a dance pad, a Wiimote, and RFID tags. We report on user feedback and derive design challenges that should be considered when creating interaction devices for IS systems.","Title: EmoVoice -- A Framework for Online Recognition of Emotions from Voice\nYear: 2008\n\nAbstract: We present EmoVoice, a framework for emotional speech corpus and classifier creation and for offline as well as real-time online speech emotion recognition. The framework is intended to be used by non-experts and therefore comes with an interface to create an own personal or application specific emotion recogniser. Furthermore, we describe some applications and prototypes that already use our framework to track online emotional user states from voice information.","Title: Managing user trust for self-adaptive ubiquitous computing systems\nYear: 2010\n\nAbstract: Ubiquitous computing systems can cause serious problems for user trust. In particular if the system is self-adaptive and situations appear which are poorly self-explanatory. In this paper we aim at the trust management of adaptive systems. We present a user study that covers the correlation of trust dimensions and user feelings on user trust. As results of this study, a Bayesian Network is introduced that, at the design time and runtime of the system, provides knowledge about the interplay between a truster's disposition, system events and actions, trust dimensions, user trust and user response.","Title: Bi-channel sensor fusion for automatic sign language recognition\nYear: 2008\n\nAbstract: In this paper, we investigate the mutual-complementary functionality of accelerometer (ACC) and electromyogram (EMG) for recognizing seven word-level sign vocabularies in German sign language (GSL). Results are discussed for the single channels and for feature-level fusion for the bichannel sensor data. For the subject-dependent condition, this fusion method proves to be effective. Most relevant features for all subjects are extracted and their universal effectiveness is proven with a high average accuracy for the single subjects. Additionally, results are given for the subject-independent condition, where subjective differences do not allow for high recognition rates. Finally we discuss a problem of feature-level fusion caused by high disparity between accuracies of each single channel classification.","Title: The Smart Sensor Integration Framework and its Application in EU Projects\nYear: 2010\n\nAbstract: Affect sensing by machines is an essential part of next-generation human-computer interaction (HCI). However, despite the large effort carried out in this field during the last decades, only few applications exist, which are able to react to a user's emotion in real-time. This is certainly due to the fact that emotion recognition is a challenging part in itself. Another reason is that so far most effort has been put towards offline analysis and only few applications exist, which can react to a user's emotion in real-time. In response to this deficit we have developed a framework called Smart Sensor Integration (SSI), which considerably jump-starts the development of multimodal online emotion recognition (OER) systems. In this paper, we introduce the SSI framework and describe how it is successfully applied in different projects under grant of the European Union, namely the CALLAS and METABO project, and the IRIS network.","Title: Lets come together: social navigation behaviors of virtual and real humans\nYear: 2005\n\nAbstract: In this paper, we present a game-like scenario that is based on a model of social group dynamics inspired by theories from the social sciences. The model is augmented by a model of proxemics that simulates the role of distance and spatial orientation in human-human communication. By means of proxemics, a group of human participants may signal other humans whether they welcome new group members to join or not. In this paper, we describe the results of an experiment we conducted to shed light on the question of how humans respond to such cues when shown by virtual humans.","Title: Xenakis: combining tangible interaction with probability-based musical composition\nYear: 2008\n\nAbstract: In this paper we present the table-based tangible interface application Xenakis which uses probability models in order to compose music in a way that can be strongly influenced by the user. Our musical sequencing application is based on a framework for tangible interfaces with an architecture that is strongly inspired by the model-view-controller pattern. In addition, we developed a hardware setup for tangible interfaces and used MatraX for tracking markers. The sequencer is the first implementation based on this framework. It allows users to create music simply by moving tangibles on the table. The graphics engine Horde3D is used to visualize the user-interaction and to show the relationships between the tangible objects on the table, creating an appealing audio-visual experience. An evaluation with 37 first time users was conducted in order to discover the strong and the weak points of such tangible user interfaces, especially in the context of our application.","Title: Gamble v2.0: social interactions with multiple users\nYear: 2005\n\nAbstract: Gamble is a test-bed for affective multiparty interactions which allows us to investigate social behavior of an agent towards users and vice versa. The CASA paradigm [9] claims that agents are regarded and treated as social actors. Whereas in 1:1 interactions it was shown that people tend to consider their \"traffic-rules\" of social interaction, we know little about scenarios in which more than one user is interacting with the same agent at the same time.","Title: Culture-related topic selection in small talk conversations across Germany and Japan\nYear: 2011\n\nAbstract: Small talk can be used in order to build a positive relationship towards a virtual character. However the choice of topics in a conversation can be dependent on social background. In this paper, we explore culture-related differences in small talk for the German and Japanese cultures. Based on findings from the literature and verified by a corpus analysis, we integrated prototypical German and Japanese small talk conversations into a multiagent system. In evaluation studies conducted in the two target cultures, we investigated whether participants prefer agent dialogs that were designed to reflect their own cultural background.","Title: Coping with temporal constraints in multimedia presentation planning\nYear: 1996\n\nAbstract: Computer-based presentation systems enable the realization of effective and dynamic presentation styles that incorporate multiple media. Obvious examples are animated user interface agents which verbally comment on multimedia objects displayed on the screen while performing cross-media and cross-window pointing gestures. The design of such presentations must account for the temporal coordination of media output and the agent's behavior. In this paper we describe a new presentation system which not only creates the multimedia objects to be presented, but also generates a script for presenting the material to the user. In our system, this script is forwarded to an animated presentation agent running the presentation. The paper details the kernel of the system which is a component for planning temporally coordinated multimedia.","Title: Too close for comfort?: adapting to the user's cultural background\nYear: 2007\n\nAbstract: The cultural context of the user is a largely neglected aspect of human centered computing. This is because culture is a very fuzzy concept and even with a computational model of culture it remains difficult to derive the necessary information to recognize the user's cultural background. Such information is only indirectly available and has to be derived from the observable multimodal behavior of the user. We propose the usage of a dimensional model of culture that allows applying computational methods to derive a user's cultural background and to adjust the system's behavior accordingly. To this end, a Bayesian network is applied to allow for the necessary inferences despite the fact that the given knowledge about the user's behavior is incomplete and unreliable.","Title: Cultural behaviors of virtual agents in an augmented reality environment\nYear: 2012\n\nAbstract: This paper presents a pilot evaluation study that investigates the physiological response of users when interacting with virtual agents that resemble cultural behaviors in an Augmented Reality environment. In particular, we analyze users from the Arab and German cultural backgrounds. The initial results of our analysis are promising and show that users tend to have a higher physiological arousal towards virtual agents that do not exhibit behaviors of their cultural background.","Title: Adaptive art --- a shape language driven approach to communicate dramaturgy and mood\nYear: 2011\n\nAbstract: Graphic designers and visual artists express their narrative intentions using visual tools which essentially include the styling of shapes. In classic art forms design decisions are limited to the initial creation process. Although technical progress makes it possible to adjust content-wise dramaturgy in real-time, the graphical design process often still has static characteristics. In our current work we therefore study how dramaturgical non-linearity can be combined with a flexible visual shape language to conform content-wise narration to visual expressiveness in real-time.","Title: NovA: Automated Analysis of Nonverbal Signals in Social Interactions\nYear: 2013\n\nAbstract: Previous studies have shown that the success of interpersonal interaction depends not only on the contents we communicate explicitly, but also on the social signals that are conveyed implicitly. In this paper, we present NovA (NOnVerbal behavior Analyzer), a system that analyzes and facilitates the interpretation of social signals conveyed by gestures, facial expressions and others automatically as a basis for computer-enhanced social coaching. NovA records data of human interactions, automatically detects relevant behavioral cues as a measurement for the quality of an interaction and creates descriptive statistics for the recorded data. This enables us to give a user online generated feedback on strengths and weaknesses concerning his social behavior, as well as elaborate tools for offline analysis and annotation.","Title: AutoSelect: What You Want Is What You Get: Real-Time Processing of Visual Attention and Affect\nYear: 2006\n\nAbstract: While objects of our focus of attention (“where we are looking at”) and accompanying affective responses to those objects is part of our daily experience, little research exists on investigating the relation between attention and positive affective evaluation. The purpose of our research is to process users' emotion and attention in real-time, with the goal of designing systems that may recognize a user's affective response to a particular visually presented stimulus in the presence of other stimuli, and respond accordingly. In this paper, we introduce the AutoSelect system that automatically detects a user's preference based on eye movement data and physiological signals in a two-alternative forced choice task. In an exploratory study involving the selection of neckties, the system could correctly classify subjects' choice of in 81%. In this instance of AutoSelect, the gaze ‘cascade effect' played a dominant role, whereas pupil size could not be shown as a reliable predictor of preference.","Title: Would you like to play with me?: how robots' group membership and task features influence human-robot interaction\nYear: 2014\n\nAbstract: In the present experiment, we investigated how robots' social category membership and characteristics of an HRI task affect humans' evaluative and behavioral reactions toward robots. Participants (N = 38) played a card game together with two robots, one belonging to participants' social in-group and the other one being a social out-group member. Furthermore, participants were either asked to cooperate with the in- and to compete with the out-group robot (congruent condition), or they were asked to cooperate with the out-group robot while competing with the in-group robot (incongruent condition). The results largely support our hypotheses: Participants showed more positive evaluative reactions toward the in-group (vs. the out-group) robot and they anthropomorphized it more strongly, independent of the congruency or incongruence of the HRI. Moreover, if required, participants cooperated with both the in- and the out-group robot, whereas their cooperativeness was more pronounced toward the in-group robot. Finally, participants indicated more difficulties with the HRI in the incongruent vs. the congruent condition. The theoretical and practical implications of the findings are discussed.","Title: Getting the mobile users in: three systems that support collaboration in an environment with heterogeneous communication devices\nYear: 2000\n\nAbstract: In this paper we present MapViews, Magic Lounge, and Call-Kiosk, three different but related systems that address the integration of mobile communication terminals into multi-user applications. MapViews is a test-bed to investigate how a small group of geographically dispersed users can jointly solve localization and route planning tasks while being equipped with different communication terminals. Magic Lounge is a virtual meeting space that provides a number of communication support services and allows its users to connect via heterogeneous devices. Finally, we sketch Call-Kiosk a system that is currently being designed for setting up a commercial information service for mobile clients. All three systems emphasize the high demand for automated design approaches which are able to generate information presentations that are tailored to the available presentation capabilities of particular target devices.","Title: I Know What I Did Last Summer: Autobiographic Memory in Synthetic Characters\nYear: 2007\n\nAbstract: According to traditional animators, the art of building believable characters resides in the ability to successfully portray a character's behaviour as the result of its internal emotions, intentions and thoughts. Following this direction, we want our agents to be able to explicitly talk about their internal thoughts and report their personal past experiences. In order to achieve it, we look at a specific type of episodic long term memory. This paper describes the integration of Autobiographic Memory into FAtiMA, an emotional agent architecture that generates emotions from a subjective appraisal of events.","Title: Catch me if you can: exploring lying agents in social settings\nYear: 2005\n\nAbstract: Embodied conversational agents become more and more realistic concerning their conversational and their nonverbal behaviors. But if the information conveyed nonverbally exhibits clues that are not consistent with the verbal part of an agent's action, how will the user react to such a discrepancy? Masking ones real emotions with a smile is a naturally occuring example of such a discrepancy. But such masks are often deficient and thus subtle clues of lying and deceiving manifest themselves in facial expressions. The questions is how users will react to these clues if they are conveyed by an agent. Will they render an application unattractive or on the contrary more human-like? In this paper, we examine such facial clues to deception and present the results of two empirical studies: i.) lies in monologues by a talking head presenting movies, ii.) lies in an interactive game of dice.","Title: Where do they look?: Gaze behaviors of multiple users interacting with an embodied conversational agent\nYear: 2005\n\nAbstract: In this paper, we describe an experiment we conducted to determine the user's level of engagement in a multi-party scenario consisting of human and synthetic interlocutors. In particular, we were interested in the question of whether humans accept a synthetic agent as a genuine conversational partner that is worthy of being attended to in the same way as the human interlocutors. We concentrated on gaze behaviors as one of the most important predictors of conversational attention.Surprisingly, humans paid more attention to an agent that talked to them than to a human conversational partner. No such effect was observed in the reciprocal case, namely when humans addressed an agent as opposed to a human interlocutor.","Title: Sprache und Raum: Natürlichsprachlicher Zugang zu visuellen Daten\nYear: 1990\n\nAbstract: Zusammenfassung Der vorliegende Beitrag befaßt sich mit der Reprasentation und Verarbeitung raumlich-zeitlichen Wissens im Hinblick auf den naturlichsprachlichen Zugang zu visuellen Daten. Im Kontext des Projektes Vitra, das sich mit der Entwicklung wissensbasierter Systeme zur Integration von maschinellem Sehen und der Ver- arbeitung naturlicher Sprache auseinandersetzt, soll diese Problemstellung naher diskutiert werden. Zunachst wird am Beispiel des Bildfolgenanalysesystems Ac- tions demonstriert, auf welche Weise Trajektorien bewegter Objekte aus Real- weltbildfolgen extrahiert werden konnen. Daran anschließend wird die in Vi- tra zugrundegelegte Schnittstelle zur Bildanalyse, die geometrische Szenenbe- schreibung, vorgestellt. Am Beispiel der lokalen orientierungsabhangigen Rela- tionenrechts, links, vor undhinter wird dann gezeigt, wie sich eine rein geometrische Darstellung in eine propositionale Beschreibung der raumlichen Anordnung ¨ uberfuhren laßt. Schließlich geht es um die Interpretation und Re- prasentation von Ereignissen, d.h. raumlich-zeitlichen Konzepten. Im Gegen- satz zu bisherigen Ansatzen soll dabei jedoch nicht von einer bereits vollstandig analysierten Bildfolge ausgegangen werden; vielmehr sind Ereignisse so zu re- prasentieren, daß sie simultan zu ihrem Auftreten in der Szene detektiert und naturlichsprachlich beschrieben werden konnen. Dieser Beitrag ist erschienen in: C. Freksa und C. Habel (Hrsg.), Reprasentation und Verarbeitung raumlichen Wissens, pp. 207-220. Berlin, Heidelberg: Sprin- ger, 1990.","Title: The social signal interpretation (SSI) framework: multimodal signal processing and recognition in real-time\nYear: 2013\n\nAbstract: Automatic detection and interpretation of social signals carried by voice, gestures, mimics, etc. will play a key-role for next-generation interfaces as it paves the way towards a more intuitive and natural human-computer interaction. The paper at hand introduces Social Signal Interpretation (SSI), a framework for real-time recognition of social signals. SSI supports a large range of sensor devices, filter and feature algorithms, as well as, machine learning and pattern recognition tools. It encourages developers to add new components using SSI's C++ API, but also addresses front end users by offering an XML interface to build pipelines with a text editor. SSI is freely available under GPL at http://openssi.net.","Title: Hand distinction for multi-touch tabletop interaction\nYear: 2009\n\nAbstract: Recent multi-touch multi-user tabletop systems offer rich touch contact properties to applications. Not only they provide touch positions, but also finger orientations. Applications can use these properties separated for each finger or derive information by combining the given touch contact data. In this paper, we present an approach to map fingers to their associated joined hand contributing to potential enhancements for gesture recognition and user interaction. For instance, a gesture can be composed of multiple fingers of one hand or different hands. Therefore, we present a simple heuristic for mapping fingers to hands that makes use of constraints applied to the touch position combined with the finger orientation. We tested our approach with collected diverse touch contact data and analyze the results.","Title: Emotional Sensitivity In Human-Computer Interaction\nYear: 2009\n\nAbstract: Human conversational partners usually try to interpret the speaker's or listener's affective cues and respond to them accordingly. Recently, the modelling and simulation of such behaviours has been recognized as an essential factor for more natural man-machine communication. The implicit emotion channels of human communication such as speech, facial expression, gesture, and physiological responses are used in general to extract emotion-relevant features for the computational perception of emotion. So far, research on emotion recognition has mostly dealt with offline analysis of recorded emotion corpora, and online processing (in realtime or near realtime) has hardly been addressed. Online processing is, however, a necessary prerequisite for the realization of human-computer interfaces that analyze and respond to the user's emotions while he or she is interacting with an application. In this paper, we first describe how we recognize emotions from various modalities including speech, gestures and biosignals. We then present Smart Sensor Integration (SSI), a framework which we developed to meet the specific requirements of online emotion recognition.","Title: The Persona Effect: How Substantial Is It?\nYear: 1998\n\nAbstract: Personification of interface agents has been speculated to have several advantages, such as a positive effect on agent credibility and on the perception of learning experience. However, important questions less often addressed so far are what effect personification has on more objective measures, such as comprehension and recall, and furthermore, under what circumstances this effect (if any) occurs. We performed an empirical study with adult participants to examine the effect of the Ppp Persona not only on subjective but also on objective measures. In addition, we tested it both with technical and non-technical domain information. The results of the study indicate that the data from the subjective measures support the so called persona effect for the technical information but not for non-technical information. With regard to the objective measures, however, neither a positive nor a negative effect could be found. Implications for software development are discussed.","Title: Emotional input for character-based interactive storytelling\nYear: 2009\n\nAbstract: In most Interactive Storytelling systems, user interaction is based on natural language communication with virtual agents, either through isolated utterances or through dialogue. Natural language communication is also an essential element of interactive narratives in which the user is supposed to impersonate one of the story's characters. Whilst techniques for narrative generation and agent behaviour have made significant progress in recent years, natural language processing remains a bottleneck hampering the scalability of Interactive Storytelling systems. In this paper, we introduce a novel interaction technique based solely on emotional speech recognition. It allows the user to take part in dialogue with virtual actors without any constraints on style or expressivity, by mapping the recognised emotional categories to narrative situations and virtual characters feelings. Our Interactive Storytelling system uses an emotional planner to drive characters' behaviours. The main feature of this approach is that characters' feelings are part of the planning domain and are at the heart of narrative representations. The emotional speech recogniser analyses the speech signal to produce a variety of features which can be used to define ad-hoc categories on which to train the system. The content of our interactive narrative is an adaptation of one chapter of the XIXth century classic novel, Madame Bovary, which is well suited to a formalisation in terms of characters' feelings. At various stages of the narrative, the user can address the main character or respond to her, impersonating her lover. The emotional category extracted from the user utterance can be analysed in terms of the current narrative context, which includes characters' beliefs, feelings and expectations, to produce a specific influence on the target character, which will become visible through a change in its behaviour, achieving a high level of realism for the interaction. A limited number of emotional categories is sufficient to drive the narrative across multiple courses of actions, since it comprises over thirty narrative functions. We report results from a fully implemented prototype, both in terms of proof of concept and of usability through a preliminary user study.","Title: A cooperative in-car game for heterogeneous players\nYear: 2011\n\nAbstract: Car rides are often perceived as dull by the passengers, especially children. Therefore, we aim to introduce a system fostering a collaborative and communicative experience in this environment. This paper presents the design for a game played together by all car-occupants, including the driver, according to their abilities and capacities. A fully implemented prototype of our system called nICE: nice In-Car Experience is evaluated under real world conditions in a user study with five families using a qualitative approach.","Title: The IRIS Network of Excellence: Integrating Research in Interactive Storytelling\nYear: 2008\n\nAbstract: Interactive Storytelling is a major endeavour to develop new media which could offer a radically new user experience, with a potential to revolutionise digital entertainment. European research in Interactive Storytelling has played a leading role in the development of the field, and this creates a unique opportunity to strengthen its position even further by structuring collaboration between some of its main actors. IRIS (Integrating Research in Interactive Storytelling) aims at creating a virtual centre of excellence that will be able to progress the understanding of fundamental aspects of Interactive Storytelling and the development of corresponding technologies.","Title: Character roles and interaction in the DynaLearn intelligent learning environment\nYear: 2011\n\nAbstract: In this paper we present the cast of pedagogical agents in the DynaLearn Intelligent Learning Environment. We describe the different character roles and how they interact with the learners. Our aim in using these characters is to increase the learners' motivation.","Title: A systematic discussion of fusion techniques for multi-modal affect recognition tasks\nYear: 2011\n\nAbstract: Recently, automatic emotion recognition has been established as a major research topic in the area of human computer interaction (HCI). Since humans express emotions through various channels, a user's emotional state can naturally be perceived by combining emotional cues derived from all available modalities. Yet most effort has been put into single-channel emotion recognition, while only a few studies with focus on the fusion of multiple channels have been published. Even though most of these studies apply rather simple fusion strategies -- such as the sum or product rule -- some of the reported results show promising improvements compared to the single channels. Such results encourage investigations if there is further potential for enhancement if more sophisticated methods are incorporated. Therefore we apply a wide variety of possible fusion techniques such as feature fusion, decision level combination rules, meta-classification or hybrid-fusion. We carry out a systematic comparison of a total of 16 fusion methods on different corpora and compare results using a novel visualization technique. We find that multi-modal fusion is in almost any case at least on par with single channel classification, though homogeneous results within corpora point to interchangeability between concrete fusion schemes.","Title: EVAL - an evaluation component for mobile interfaces\nYear: 2008\n\nAbstract: The Eval Tool is a usability evaluation environment which can be used to evaluate users an their behaviour while they interact with their pervasive computing environment via a mobile phone interface. The tool supports audio-visual recordings of several users and automatically annotates and synchronizes them with context data emerging from the pervasive environment. The annotation of video material with contextual information is important for the analysis of user studies and the detection of usability issues. The EVAL Tool consists of a recorder and a analyzer component. Using the recorder component the capturing of the videos and the logging of the context can be controlled whereas the analyzer components helps to interpret the user study.","Title: Zur multimedialen Präsentation von Handlungsalternativen in Verkehrsmanagement- und Verkehrssimulationssystemen\nYear: 1998\n\nAbstract: Eine pr?gnante und zugleich wirkungsvolle Informationspr?sentation l??t sich vielfach nur durch den Einsatz unterschiedlicher Medien erzielen, insbesondere durch aufeinander abgestimmte Medienkombinationen, wie illustrierte Texte, oder sprachlich begleitete Animationen. Geteilt wird diese Einsch?tzung auch zunehmend von Entwicklern sog. Entscheidungsunterstützungssysteme (EUS), die heute verbreitet zur Bew?ltigung von Transport/Verkehrsmanagementaufgaben zum Einsatz kommen. Komplexe Pr?sentationsaufgaben mit hoher Datenvarianz sind in solchen Systemen jedoch ohne Einsatz intelligenter Verfahren zur Generierung multimedialer Pr?sentationen kaum mehr zu bew?ltigen. Der vorliegende Beitrag thematisiert das Pr?sentationsproblem in zeitkritischen Anwendungen. Anhand eines konkreten Einsatzszenarios im Bereich der Verkehrsüberwachung,-simulation und-steuerung wird ein Ansatz zur automatischen Pr?sentationsgestaltung aufgezeigt. Eine Besonderheit des Ansatzes ist sein Verm?gen, mitzuteilende Handlungsalternativen durch geeignete Medienkombinationen in aggregierter Form darzubieten.","Title: Surface-poker: multimodality in tabletop games\nYear: 2010\n\nAbstract: Multimodal interaction and face-to-face communication between players are aspects of traditional board games which contribute to their popularity. Such aspects are also typical of digital tabletop games. But in addition to that, digital systems allow for a higher level of multimodality through utilizing novel interaction devices or physiological input data. In this paper, we describe a multimodal tabletop Poker game which makes use of both: additional interaction devices and physiological input data. We outline the tabletop game, the interaction modalities involved, and observations of players.","Title: Studying user-defined iPad gestures for interaction in multi-display environment\nYear: 2012\n\nAbstract: The paper investigates the iPad gestures that users naturally perform for data transfer. We examine the transfer between two iPads, iPad and a tabletop, and iPad and a public display. Three gesture modalities are investigated: multi-touch gestures, performed using iPad display, spatial gestures, performed by manipulating iPad in 3D space, and direct contact gestures, involving the physical contact of iPad and other device. We report on user choices of the modalities and gesture types, and derive critical points for the design of iPad gestures.","Title: Let's come together: social navigation behaviors of virtual and real humans\nYear: 2005\n\nAbstract: In this paper, we present a game-like scenario that is based on a model of social group dynamics inspired by theories from the social sciences. The model is augmented by a model of proxemics that simulates the role of distance and spatial orientation in human-human communication. By means of proxemics, a group of human participants may signal other humans whether they welcome new group members to join or not. In this paper, we describe the results of an experiment we conducted to shed light on the question of how humans respond to such cues when shown by virtual humans.","Title: Modeling parallel state charts for multithreaded multimodal dialogues\nYear: 2011\n\nAbstract: In this paper, we present a modeling approach for the management of highly interactive, multithreaded and multimodal dialogues. Our approach enforces the separation of dialogue content and dialogue structure and is based on a statechart language enfolding concepts for hierarchy, concurrency, variable scoping and a detailed runtime history. These concepts facilitate the modeling of interactive dialogues with multiple virtual characters, autonomous and parallel behaviors, flexible interruption policies, context-sensitive interpretation of the user's discourse acts and coherent resumptions of dialogues. An interpreter allows the realtime visualization and modification of the model to allow a rapid prototyping and easy debugging. Our approach has successfully been used in applications and research projects as well as evaluated in field tests with non-expert authors. We present a demonstrator illustrating our concepts in a social game scenario.","Title: Discovering eye gaze behavior during human-agent conversation in an interactive storytelling application\nYear: 2010\n\nAbstract: In this paper, we investigate the user's eye gaze behavior during the conversation with an interactive storytelling application. We present an interactive eye gaze model for embodied conversational agents in order to improve the experience of users participating in Interactive Storytelling. The underlying narrative in which the approach was tested is based on a classical XIXth century psychological novel: Madame Bovary, by Flaubert. At various stages of the narrative, the user can address the main character or respond to her using free-style spoken natural language input, impersonating her lover. An eye tracker was connected to enable the interactive gaze model to respond to user's current gaze (i.e. looking into the virtual character's eyes or not). We conducted a study with 19 students where we compared our interactive eye gaze model with a non-interactive eye gaze model that was informed by studies of human gaze behaviors, but had no information on where the user was looking. The interactive model achieved a higher score for user ratings than the non-interactive model. In addition we analyzed the users' gaze behavior during the conversation with the virtual character.","Title: Influence of head orientation in perception of personality traits in virtual agents\nYear: 2011\n\nAbstract: The aim of this research is to explore the influence of static visual cues on the perception of a character's personality traits: extraversion, agreeableness and emotional stability. To measure how users perceived personality, we conducted a web-based study with 133 subjects who rated 54 images of a virtual character with varying head orientations and gaze.","Title: Traveller: an intercultural training system with intelligent agents\nYear: 2013\n\nAbstract: There is a growing demand for new forms of intercultural training. We describe a demonstration of an agent-based application designed to teach young adults (18-25) general patterns of behaviour that can distinguish a broad range of cultures. Training is done through an interactive-story telling approach where the user must go through a series of critical incidents, interacting with agents capable of simulating different synthetic cultures in their behaviour.","Title: Friend or foe? relationship-based adaptation on public displays\nYear: 2011\n\nAbstract: Personalization of content on public displays is likely to cause the disclosure of user's private data. In order to protect the user's privacy, different protection strategies are used, e.g. the private data is hidden, occluded or blurred. Existing systems usually follow a uniform protection strategy, applying it every time a spectator is detected in the display proximity. However, the necessity in privacy protection often depends on the personal relationships between the user and the spectator. This work investigates how the relationship context influences user preferences in adaptation strategies. Additionally, we study how privacy level of data and the presence of a mobile device influence this preference. The obtained results can guide adaptation designers in creation of more flexible privacy protection mechanisms.","Title: Mobile augmented reality and adaptive art: a game-based motivation for energy saving\nYear: 2012\n\nAbstract: We present the design of an educational treasure hunt game that uses mobile Augmented Reality (AR) and adaptive virtual gardens to raise awareness on energy consumption ways. Within the game, AR is used to present 3D content that allows for visually understanding the energy consumption problems and their solutions. In addition, the players' performances are given in a form of a visual feedback as dynamic virtual gardens that change from poor to good status. Initial tests show that the presented game is highly appealing to players and motivated them to be aware of the presented problem using AR technologies and the visual effects of their virtual garden's health. Future work will focus on evaluating the learnability and engagement of players.","Title: Enculturating conversational interfaces by socio-cultural aspects of communication\nYear: 2008\n\nAbstract: The workshop is centered around three main research challenges: 1.) Computationally viable models of cultural aspects of conversations: Cultural norms and values penetrate all our communications and interactions by giving us heuristics how to behave and how to interpret the verbal and nonverbal behavior of others. To make such a notion like culture available for computation, we need a very specific theory of culture that takes its effects on communication and interaction into account.2.) Reliable empirical data on cultural/cross-cultural interaction: To realize technical systems that take cultural influences on behavior into account, precise data analysis on how this influence manifests itself is necessary. In the literature, this information is often given in very general forms without to the precise data on which the observations are based.3.) Enculturating conversational interfaces: Having identified cultural influences on verbal/nonverbal communicative behaviors, it remains to be shown how this can be applied to the development of human-computer interfaces, for instance in an interface reflecting cultural norms and values of communication.","Title: Incremental Natural Language Description of Dynamic Imagery\nYear: 1989\n\nAbstract: Although image understanding and natural language processing constitute two major areas of AI, they have mostly been studied independently of each other. Only a few attempts have been concerned with the integration of computer vision and the generation of natural language expressions for the description of image sequences.","Title: A Generate-And-Sense Approach To Automated Music Composition\nYear: 2005\n\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user-specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.","Title: A generate and sense approach to automated music composition\nYear: 2004\n\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user-specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.","Title: Architecture of a ubiquitous smart energy management system for residential homes\nYear: 2011\n\nAbstract: A range of technology for monitoring electricity consumption at residential homes is gradually becoming available to users. Almost all of these systems, however, only aim to assist users with reducing their total power consumption, without being concerned too much about how those savings are actually made. Our research, aims to provide a basis for design of systems that give users control over management of power usage, so that savings in energy consumption can be made more intelligently. This paper describes the requirements of such a system, and proposes an architecture for these types of ubiquitous systems for residential homes.","Title: Presenting through performing: on the use of multiple lifelike characters in knowledge-based presentation systems\nYear: 2000\n\nAbstract: In this paper, we investigate a new style for presenting information. We introduce the motion of presentation teams which — rather than addressing the user directly — convey information in the style of performances to be observed by him or her. The paper presents an approach to the automated generation of performances which has been tested in two different application scenarios, car sales dialogues and soccer commentary.","Title: A Framework for User-Defined Body Gestures to Control a Humanoid Robot.\nYear: 2014\n\nAbstract: This paper presents a framework that allows users to interact with and navigate a humanoid robot using body gestures. The first part of the paper describes a study to define intuitive gestures for eleven navigational commands based on analyzing 385 gestures performed by 35 participants. From the study results, we present a taxonomy of the user-defined gesture sets, agreement scores for the gesture sets, and time performances of the gesture motions. The second part of the paper presents a full body interaction system for recognizing the user-defined gestures. We evaluate the system by recruiting 22 participants to test for the accuracy of the proposed system. The results show that most of the defined gestures can be successfully recognized with a precision between 86100 % and an accuracy between 7396 %. We discuss the limitations of the system and present future work improvements.","Title: XIM-engine: a software framework to support the development of interactive applications that uses conscious and unconscious reactions in immersive mixed reality\nYear: 2014\n\nAbstract: The development of systems that allow multimodal interpretation of human-machine interaction is crucial to advance our understanding and validation of theoretical models of user behavior. In particular, a system capable of collecting, perceiving and interpreting unconscious behavior can provide rich contextual information for an interactive system. One possible application for such a system is in the exploration of complex data through immersion, where massive amounts of data are generated every day both by humans and computer processes that digitize information at different scales and resolutions thus exceeding our processing capacity. We need tools that accelerate our understanding and generation of hypotheses over the datasets, guide our searches and prevent data overload. We describe XIM-engine, a bio-inspired software framework designed to capture and analyze multi-modal human behavior in an immersive environment. The framework allows performing studies that can advance our understanding on the use of conscious and unconscious reactions in interactive systems.","Title: Augmenting Social Interactions: Realtime Behavioural Feedback using Social Signal Processing Techniques\nYear: 2015\n\nAbstract: Nonverbal and unconscious behaviour is an important component of daily human-human interaction. This is especially true in situations such as public speaking, job interviews or information sensitive conversations, where researchers have shown that an increased awareness of one's behaviour can improve the outcome of the interaction. With wearable technology, such as Google Glass, we now have the opportunity to augment social interactions and provide realtime feedback on one's behaviour in an unobtrusive way. In this paper we present Logue, a system that provides realtime feedback on the presenters' openness, body energy and speech rate during public speaking. The system analyses the user's nonverbal behaviour using social signal processing techniques and gives visual feedback on a head-mounted display. We conducted two user studies with a staged and a real presentation scenario which yielded that Logue's feedback was perceived helpful and had a positive impact on the speaker's performance.","Title: Modeling Gaze Mechanisms for Grounding in HRI.\nYear: 2014\n\nAbstract: Grounding is essential in human interaction and crucial for social robots collaborating with humans. Gaze plays versatile roles for establishing, maintaining and repairing the common ground. It is combined with parallel modalities and involved in several processes for behavior generation and recognition. We present a uniform modeling approach focusing on the multi-modal, parallel and bidirectional aspects of gaze and their interleaving with the dialog logic.","Title: An Event Driven Fusion Approach for Enjoyment Recognition in Real-time\nYear: 2014\n\nAbstract: Social signals and interpretation of carried information is of high importance in Human Computer Interaction. Often used for affect recognition, the cues within these signals are displayed in various modalities. Fusion of multi-modal signals is a natural and interesting way to improve automatic classification of emotions transported in social signals. Throughout most present studies, uni-modal affect recognition as well as multi-modal fusion, decisions are forced for fixed annotation segments across all modalities. In this paper, we investigate the less prevalent approach of event driven fusion, which indirectly accumulates asynchronous events in all modalities for final predictions. We present a fusion approach, handling short-timed events in a vector space, which is of special interest for real-time applications. We compare results of segmentation based uni-modal classification and fusion schemes to the event driven fusion approach. The evaluation is carried out via detection of enjoyment-episodes within the audiovisual Belfast Story-Telling Corpus.","Title: A framework for the development of multi-display environment applications supporting interactive real-time portals\nYear: 2014\n\nAbstract: Advances in multi-touch enabled interactive tabletops led to many commercially available products and were increasingly deployed at places beyond research labs, for example at exhibitions, retail stores, or showrooms. At the same time, small multi-touch devices, such as tablets or smartphones, became prevalent in our daily life. When considering both trends, occasions and scenarios where tabletop systems and mobile devices form a coupled interaction space are expected to become increasingly widespread. However, application development or research prototypes for those environments will foreseeable require considerable resources when considering nowadays heterogeneity of device platforms and the functionality to establish a connected interaction space. To address these concerns, this paper discusses challenges and answers questions that arose during design and implementation of the Environs framework, a multi-display environment software framework that eases development of interactive distributed applications. In particular, Environs enables applications utilizing video portals that put high requirements on responsiveness and latency.","Title: A Multi-Display System for Deploying and Controlling Home Automation\nYear: 2014\n\nAbstract: In this paper, we present a concept of using a home devices mashup tool to wire home devices on a tabletop display in combination with web based UIs on mobile devices to control home devices. This concept is realized by a multi-display system supported by the open-source framework Environs. The mashup tool on the tabletop enables multiple people to deploy home networked devices co-located collaboratively with a more natural and intuitive interface. Moreover, web based UIs on mobile devices enable individuals to control home devices universally with high accessibility and mobility.","Title: Challenges for Social Embodiment\nYear: 2014\n\nAbstract: Current research in the area of social signal processing focuses on offline analysis of previously recorded human social cues. Approaches to exploit social signal processing techniques in naturalistic environments where agents socially interact with humans are rare and typically focus on isolated aspects, such as the creation of appropriate head nods or gaze behaviors. This position paper aims to identify challenges and research objectives for the area of social signal processing in order to encourage applications with more advanced forms of social embodiment in interactive settings.","Title: Exploring a Model of Gaze for Grounding in Multimodal HRI\nYear: 2014\n\nAbstract: Grounding is an important process that underlies all human interaction. Hence, it is crucial for building social robots that are expected to collaborate effectively with humans. Gaze behavior plays versatile roles in establishing, maintaining and repairing the common ground. Integrating all these roles in a computational dialog model is a complex task since gaze is generally combined with multiple parallel information modalities and involved in multiple processes for the generation and recognition of behavior. Going beyond related work, we present a modeling approach focusing on these multi-modal, parallel and bi-directional aspects of gaze that need to be considered for grounding and their interleaving with the dialog and task management. We illustrate and discuss the different roles of gaze as well as advantages and drawbacks of our modeling approach based on a first user study with a technically sophisticated shared workspace application with a social humanoid robot.","Title: Modeling Grounding for Interactive Social Companions\nYear: 2016\n\nAbstract: Grounding is an important process that underlies all human interaction. Hence, it is also crucial for social companions to interact naturally. Maintaining the common ground requires domain knowledge but has also numerous social aspects, such as attention, engagement and empathy. Integrating these aspects and their interplay with the dialog management in a computational interaction model is a complex task. We present a modeling approach overcoming this challenge and illustrate it based on some social companion applications.","Title: A cross-cultural, multimodal, affective corpus for gesture expressivity analysis\nYear: 2013\n\nAbstract: A multimodal, cross-cultural corpus of affective behavior is presented in this research work. The corpus construction process, including issues related to the design and implementation of an experiment, is discussed along with resulting acoustic prosody, facial expressions and gesture expressivity features. However, research work presented here focuses more on the cross-cultural aspect of gestural behavior defining a common corpus construction protocol aiming to identify cultural patterns within non-verbal behavior across cultures i.e. German, Greek and Italian. Culture specific findings regarding gesture expressivity are derived from the affective analysis performed. Additionally, the multimodal aspect, including prosody and facial expressions, is researched in terms of fusion techniques. Finally, a release plan of the corpus to the public domain is discussed aiming to establish the current corpus as a benchmark multimodal, cross-cultural standard and reference point.","Title: Context-Aware Automated Analysis and Annotation of Social Human--Agent Interactions\nYear: 2015\n\nAbstract: The outcome of interpersonal interactions depends not only on the contents that we communicate verbally, but also on nonverbal social signals. Because a lack of social skills is a common problem for a significant number of people, serious games and other training environments have recently become the focus of research. In this work, we present NovA (Nonverbal behavior Analyzer), a system that analyzes and facilitates the interpretation of social signals automatically in a bidirectional interaction with a conversational agent. It records data of interactions, detects relevant social cues, and creates descriptive statistics for the recorded data with respect to the agent's behavior and the context of the situation. This enhances the possibilities for researchers to automatically label corpora of human--agent interactions and to give users feedback on strengths and weaknesses of their social behavior.","Title: Trust-based decision-making for smart and adaptive environments\nYear: 2015\n\nAbstract: Smart environments are able to support users during their daily life. For example, smart energy systems can be used to support energy saving by controlling devices, such as lights or displays, depending on context information, such as the brightness in a room or the presence of users. However, proactive decisions should also match the users’ preferences to maintain the users’ trust in the system. Wrong decisions could negatively influence the users’ acceptance of a system and at worst could make them abandon the system. In this paper, a trust-based model, called User Trust Model (UTM), for automatic decision-making is proposed, which is based on Bayesian networks. The UTM’s construction, the initialization with empirical data gathered in an online survey, and its integration in an office setting are described. Furthermore, the results of a live study and a live survey analyzing the users’ experience and acceptance are presented.","Title: Open Challenges in Modelling, Analysis and Synthesis of Human Behaviour in Human–Human and Human–Machine Interactions\nYear: 2015\n\nAbstract: Modelling, analysis and synthesis of behaviour are the subject of major efforts in computing science, especially when it comes to technologies that make sense of human–human and human–machine interactions. This article outlines some of the most important issues that still need to be addressed to ensure substantial progress in the field, namely (1) development and adoption of virtuous data collection and sharing practices, (2) shift in the focus of interest from individuals to dyads and groups, (3) endowment of artificial agents with internal representations of users and context, (4) modelling of cognitive and semantic processes underlying social behaviour and (5) identification of application domains and strategies for moving from laboratory to the real-world products.","Title: Natural interaction with culturally adaptive virtual characters\nYear: 2012\n\nAbstract: Recently, the verbal and non-verbal behavior of virtual characters has become more and more sophisticated due to advances in behavior planning and rendering. Nevertheless, the appearance and behavior of these characters is in most cases based on the cultural background of their designers. Especially in combination with new natural interaction interfaces, there is the risk that characters developed for a particular culture might not find acceptance when being presented to another culture. A few attempts have been made to create characters that reflect a particular cultural background. However, interaction with these characters still remains an awkward experience in particular when it comes to non-verbal interaction. In many cases, human users either have to choose actions from a menu their avatar has to execute or they have to struggle with obtrusive interaction devices. In contrast, our paper combines an approach to the generation of culture-specific behaviors with full body avatar control based on the Kinect sensor. A first study revealed that users are able to easily control an avatar through their body movements and immediately adapt its behavior to the cultural background of the agents they interact with.","Title: The Belfast storytelling database: A spontaneous social interaction database with laughter focused annotation\nYear: 2015\n\nAbstract: To support the endeavor of creating intelligent interfaces between computers and humans the use of training materials based on realistic human-human interactions has been recognized as a crucial task. One of the effects of the creation of these databases is an increased realization of the importance of often overlooked social signals and behaviours in organizing and orchestrating our interactions. Laughter is one of these key social signals; its importance in maintaining the smooth flow of human interaction has only recently become apparent in the embodied conversational agent domain. In turn, these realizations require training data that focus on these key social signals. This paper presents a database that is well annotated and theoretically constructed with respect to understanding laughter as it is used within human social interaction. Its construction, motivation, annotation and availability are presented in detail in this paper.","Title: Socially-Sensitive Interfaces: From Offline Studies to Interactive Experiences.\nYear: 2016\n\nAbstract: Recent years have initiated a paradigm shift from pure taskbased human-machine interfaces towards socially-sensitive interaction. In addition to what users explicitly say or gesture at, socially-sensitive interfaces are able to sense more subtle human cues, such as head postures and movements, to infer psychological user states, such as attention and affect, and also to enrich system responses with social signals. However, most approaches focus on offline analysis of previously recorded data limiting the investigation to prototypical behaviors in laboratory-like settings. In my presentation, I will focus on challenges that arise when integrating social signal processing techniques into interactive systems designed for real-world applications. From a technical perspective, this requires effective tools able to synchronize, process, and analyze relevant signals in online mode. From a user perspective, appropriate strategies need to be defined to respond to social signals at the right moment in time without disturbing the flow of interaction. I will discuss two interaction styles for socially-sensitive interfaces. In the area of information retrieval, the concept of empathic stimulation has been used to optimize the selection and presentation of data. The basic idea is to exploit sensory data on the users' emotional state to provide them with cues that inspire their curiosity during the data exploration task. In the domain of social coaching, the concept of social augmentation has been employed to give people ambient feedback on their behavior while being engaged in a social interaction. The presentation will be illustrated by examples from various national and international projects following these two interaction styles.","Title: Combining Hierarchical Classification With Frequency Weighting For The Recognition Of Eating Conditions\nYear: 2015\n\nAbstract: Though parents regularly remind their children not to do so, talking while eating is a typical everyday situation automatic speech analysis systems should be able to deal with. The Paralinguistic Eating Condition (EC) Challenge at INTERSPEECH 2015 sets the task to classify whether a speaker is eating or not, and if so, which type of food the speaker is currently tasting. The approach we follow in this paper is rather unusual: instead of suppressing the influence of noise to enhance the intelligibility of a spoken message, we try to emphasize the noisy parts of the spectrum to improve the recognition of food classes. To allow for a fine-grained adaption to the characteristic spectrum of single food types we adopt a hierarchical tree structure and decompose the classification task into a sequence of binary decisions. At each node we apply frequency-dependent weighting to tune the spectrum to the involved target classes. With our approach we are able to improve results in a 7-class recognition problem (6 types of food and no food) by more than 7% on the training set (using leave-one-eater-out cross validation) and 4% on the test set, respectively.","Title: Games Are Better Than Books: In-Situ Comparison Of An Interactive Job Interview Game With Conventional Training\nYear: 2015\n\nAbstract: Technology-enhanced learning environments are designed to help users practise social skills. In this paper, we present and evaluate a virtual job interview training game which has been adapted to the special requirements of young people with low chances on the job market. The evaluation spanned three days, during which we compared the technology-enhanced training with a traditional learning method usually practised in schools, i.e. reading a job interview guide. The results are promising as professional career counsellors rated the pupils who trained with the system significantly better than those who learned with the traditional method.","Title: Exploring Digital Image Frames for Lifestyle Intervention to Improve Well-being of Older Adults\nYear: 2015\n\nAbstract: This contribution addresses the development of technology for senior users with the aim to improve their general wellbeing. We present a prototype system named CARE that is used for in-situ testing in a senior's home and combines functionality of a digital image frame with an active recommender mode. The purpose of the recommender is to provide the user with context-specific recommendations. Recommendations are chosen on the basis of sensor data and a well-being model to carefully decide on at which point in time what kind of activity will be most suitable to suggest.","Title: Modeling and Evaluating a Bayesian Network of Culture-Dependent Behaviors\nYear: 2015\n\nAbstract: Anthropomorphic user interfaces such as virtual agents or humanoid robots aim on simulating believable human behavior. As human behavior is influenced by diversifying factors such as cultural background, research in anthropomorphic user interfaces considers culture background for their behavioral models as well. This paper presents a hybrid approach of creating a culture-specific model of non-verbal behaviors for simulated dialogs based on both: theoretical knowledge and empirical data. Therefore, the structure and variables of a Bayesian network are designed based on models and theories from the social sciences, while its parameters are learned from a video corpus of German and Japanese conversations in first time meeting scenarios. To validate the model a 10-fold-cross-validation has been conducted, suggesting that with the model culture-specific behavior can automatically be generated for some of the investigated behavioral aspects.","Title: Investigating Politeness Strategies and Their Persuasiveness for a Robotic Elderly Assistant.\nYear: 2016\n\nAbstract: This work is targeted towards the development of a Robotic Elderly Assistant REA system that provides assistance in the form of recommendations to support single-living elderly people in their domestic environment. To avoid potential face threats the REA should be as polite as possible whilst keeping a certain persuasiveness to promote its recommendations. This paper investigates different verbalizations of the REA's recommendations regarding their perceived politeness as well as their persuasiveness. We present the results of a laboratory study with younger adults and a user study with the inhabitants of a retirement home. Results suggest that the different politeness strategies reflected different levels of politeness in both studies, while their perceived persuasiveness needs further investigation in the domain of elderly care.","Title: Fostering Smart Energy Applications\nYear: 2015\n\nAbstract: There is an increasing need for smart applications with interactive visual interfaces that allow users to better manage and monitor their energy generation and consumption. This workshop will bring together researchers and practitioners from interaction design, human-computer interaction, visualization, computer games, and media technology to foster research, design, development, and deployment of energy-related applications, tools, services, games, and persuasive technologies.","Title: Exploring the Potential of Realtime Haptic Feedback during Social Interactions.\nYear: 2016\n\nAbstract: We explore the use of haptic feedback to deliver supportive information during social interactions in realtime. In an exploratory user study, we investigated perceptual limitations of vibration patterns during a conversation between peers. The results from this study have then been used to develop a system for providing users with realtime information regarding the quality of their nonverbal behaviour while engaged in a public speech.","Title: How Can I Interact?: Comparing Full Body Gesture Visualizations\nYear: 2015\n\nAbstract: This paper is dedicated to the question \\\"How can I interact?\\\", which may arise during a full body interaction game. To answer this question, a game needs to tell the players what actions are available and how those actions can be triggered. We focus on the video channel and use onscreen symbols to visualize how available input gestures have to be performed. We describe three symbol variants using recordings of a real person: color images, tracking shapes and skeletons, and solely tracking skeletons. An initial evaluation study shows clear advantages for the color images. We further outline how we extend the current implementation, for both improving the usability of the symbols, as well as easing their development.","Title: Visualization Support for Comparing Energy Consumption Data\nYear: 2015\n\nAbstract: Providing effective feedback can empower users to change their behaviour and take the necessary actions to reduce their energy consumption. The types of feedback that allow comparison of energy usage seem to be particularly valuable. This paper introduces the time-stack visualization, which has been designed to support comparisons of individual and collective energy usage data. It also describes a user study conducted to compare the effectiveness of time-stack against a similar visualization called time-pie. The results show that although the two visualizations are generally comparable in their effectiveness, users rate time-stack more favourably.","Title: Exploring Eye-Tracking-Driven Sonification for the Visually Impaired.\nYear: 2016\n\nAbstract: Most existing sonification approaches for the visually impaired restrict the user to the perception of static scenes by performing sequential scans and transformations of visual information to acoustic signals. This takes away the user's freedom to explore the environment and to decide which information is relevant at a given point in time. As a solution, we propose an eye tracking system to allow the user to choose which elements of the field of view should be sonified. More specifically, we enhance the sonification approaches for color, text and facial expressions with eye tracking mechanisms. To find out how visually impaired people might react to such a system we applied a user centered design approach. Finally, we explored the effectiveness of our concept in a user study with seven visually impaired persons. The results show that eye tracking is a very promising input method to control the sonification, but the large variety of visual impairment conditions restricts the applicability of the technology.","Title: Design of a lifestyle recommender system for the elderly: requirement gatherings in Germany and Greece\nYear: 2015\n\nAbstract: As overaging is becoming a main societal challenge, the development of AAL (Ambient Assisted Living) systems has become the centre of many research projects the last years. Our own work is targeted towards the development of an AAL system -called CARE- that provides assistance in form of recommendations helping its users overcome typical difficulties of everyday life, and contributes positively to their well-being. To inform the design of the envisioned CARE system we recruited two peer groups of potential users, a group of 20 Greek seniors, and a group of 27 German seniors, and conducted structured interviews which were focused on the seniors' life-style, medical needs, attitude towards AAL technologies, and, more specifically, on desired functions and system configurations of a recommendation-giving CARE system. We discuss outcomes of the conducted interviews and sketch a first CARE prototype which appears as an augmented digital picture frame that interleaves the display of photos with recommendations and interventions to improve the seniors' life-style and well-being.","Title: Stress Recognition in Daily Work.\nYear: 2015\n\nAbstract: Automatic detection of work-related stress has attracted an increasing amount of attention from researchers from various disciplines and industries. An experiment is discussed in this paper that was designed to evaluate the efficacy of multimodal sensor measures that have often been used but not yet been systematically tested and compared with each other in previous work, such as pressure distribution sensor, physiological sensors, and an eye tracker. We used the Stroop test and information pick up task as the stressors. In the subject independent case in particular, signals from the combined (chair and floor) pressure distribution sensors, which we consider the most feasible sensors in the office environment, resulted in higher recognition accuracy rates than the physiological or eye tracker signals for the two stressors.","Title: Exploring Eye-Tracking-Based Detection of Visual Search for Elderly People\nYear: 2016\n\nAbstract: Visual search plays an important role in our daily lives and can be very frustrating whenever we cannot remember where we left objects, such as keys or wallets. This is especially true for elderly people, since they forget things more often and face this challenge very frequently. While there are several studies which analyze eye movements during visual search, none of them actually tries to detect whether a user is searching for something or not. However, this information is necessary to recognize when the user needs assistance. Therefore, we propose an eye-tracking-based multimodal approach in order to detect visual search and to support the user in that situation. Furthermore, we explore multiple strategies to inform the user of the desired object's location using a head mounted display. With the help of a prototypical implementation and evaluation of the acquired sensor data, we show that our method is feasible and capable of dealing with this challenge.","Title: MobileSSI - A Multi-modal Framework for Social Signal Interpretation on Mobile Devices\nYear: 2016\n\nAbstract: Over the last years, new generations of mobile devices have found their way into our pockets. They provide more and more computational power and memory capacity to perform complex calculations that formerly could only be accomplished with bulky desktop machines. Moreover, mobile devices are equipped with a range of sensors to capture people's motion, environmental sound etc. These capabilities combined with the willingness of people to permanently carry them around open up completely new ways of observing human behaviour no longer in laboratories, but \"in the wild\". However, the detection and analysis of social cues is still a challenging task and requires adequate tools to synchronise, process and analyse relevant signals. This may be the reason why many studies and applications focus on offline analysis and typically collect data over long periods of time and analyse them afterwards. To allow for immediate feedback, real-time assessment is necessary. In this paper, we present MobileSSI, a port of the Social Signal Interpretation (SSI) framework to Android and embedded Linux platforms. The framework supports the joint development of processing pipelines for the analysis of social signals on a desktop computer and mobile devices. Throughout the paper we report on challenges we had to face when porting SSI to a mobile context. Furthermore, we summarise first experiences with a real-life setting in a pub where we focused on the analysis of multimodal social group dynamics investigating laughter as a sign of enjoyment.","Title: Ask Alice: an artificial retrieval of information agent.\nYear: 2016\n\nAbstract: We present a demonstration of the ARIA framework, a modular approach for rapid development of virtual humans for information retrieval that have linguistic, emotional, and social skills and a strong personality. We demonstrate the framework's capabilities in a scenario where `Alice in Wonderland', a popular English literature book, is embodied by a virtual human representing Alice. The user can engage in an information exchange dialogue, where Alice acts as the expert on the book, and the user as an interested novice. Besides speech recognition, sophisticated audio-visual behaviour analysis is used to inform the core agent dialogue module about the user's state and intentions, so that it can go beyond simple chat-bot dialogue. The behaviour generation module features a unique new capability of being able to deal gracefully with interruptions of the agent.","Title: Social signal processing for dummies.\nYear: 2016\n\nAbstract: We introduce SSJ Creator, a modern Android GUI enabling users to design and execute social signal processing pipelines using nothing but their smartphones and without writing a single line of code. It is based on a modular Java-based social signal processing framework (SSJ), which is able to perform realtime multimodal behaviour analysis on Android devices using both device internal and external sensors.","Title: MobileSSI: asynchronous fusion for social signal interpretation in the wild.\nYear: 2016\n\nAbstract: Over the last years, mobile devices have become an integral part of people's everyday life. At the same time, they provide more and more computational power and memory capacity to perform complex calculations that formerly could only be accomplished with bulky desktop machines. These capabilities combined with the willingness of people to permanently carry them around open up completely new perspectives to the area of Social Signal Processing. To allow for an immediate analysis and interaction, real-time assessment is necessary. To exploit the benefits of multiple sensors, fusion algorithms are required that are able to cope with data loss in asynchronous data streams. In this paper we present MobileSSI, a port of the Social Signal Interpretation (SSI) framework to Android and embedded Linux platforms. We will test to what extent it is possible to run sophisticated synchronization and fusion mechanisms in an everyday mobile setting and compare the results with similar tasks in a laboratory environment.","Title: Laughter detection in the wild: demonstrating a tool for mobile social signal processing and visualization.\nYear: 2016\n\nAbstract: In this demo, we present MobileSSI, a flexible software framework for Android and embedded Linux platforms, that provides developers with tools to record, analyze and recognize human behavior in real-time on mobile devices. To illustrate the benefits of the framework for the analysis of social group dynamics in naturalistic mobile settings, we present a demonstrator for laughter recognition that was implemented with MobileSSI. The demonstrator makes use of smartphones for sensing and analyzing data and employs smartwatches and tablets for visualizing the results and providing user feedback. To enable communication within the resulting ecology of mobile devices, MobileSSI includes a web socket plugin.","Title: Measuring the impact of multimodal behavioural feedback loops on social interactions.\nYear: 2016\n\nAbstract: In this paper we explore the concept of automatic behavioural feedback loops during social interactions. Behavioural feedback loops (BFL) are rapid processes which analyse the behaviour of the user in realtime and provide the user with live feedback on how to improve the behaviour quality. In this context, we implemented an open source software framework for designing, creating and executing BFL on Android powered mobile devices. To get a better understanding of the effects of BFL on face-to-face social interactions, we conducted a user study and compared between four different BFL types spanning three modalities: tactile, auditory and visual. For the study, the BFL have been designed to improve the users' perception of their speaking time in an effort to create more balanced group discussions. The study yielded valuable insights into the impact of BFL on conversations and how humans react to such systems.","Title: LeapArm-Facilitating Sensory Spaces for Mid-air Gestural Interaction.\nYear: 2016\n\nAbstract: We present the LeapArm system, which combines a Leap Motion controller for mid-air gestural human-computer interaction with a robotic arm. LeapArm actuates in real-time the orientation of the controller towards a user's hand, dynamically expanding the sensory space for mid-air interaction. We describe several desktop use scenarios and rapid transitions between them, which are enabled by the LeapArm system and discuss how actuated 3D controllers change the design space for gestural interaction.","Title: Hold my Heart and Breathe with Me: Tangible Somaesthetic Designs.\nYear: 2016\n\nAbstract: We present two tangible somaesthetic designs. The first design resembles a real heart, which allows users to experience their own heart's behavior by providing haptic feedback. Thus, users holding the heart design are able to feel their heartbeat in their hands. The second design is a stuffed animal, which is capable to breathe in synchrony with a user. Both designs were used as probes in a workshop with two experts practicing and teaching a meditation technique referred to as mindfulness-based stress reduction (MBSR). We conclude that tangible designs may guide users' attention away from themselves towards something outside their bodies (i.e., the artifact). Despite this possibly undesired effect, we argue that there is some potential to exploit tangible designs as mediating tools to address wellbeing for challenging user groups, such as children.","Title: Pen + Mid-Air: An Exploration of Mid-Air Gestures to Complement Pen Input on Tablets.\nYear: 2016\n\nAbstract: In this paper, we report on a series of studies, exploring the potential of pen and mid-air input on tablets. We describe a field study with an early prototype of a drawing application and follow-up inquiries, such as the development and comparison of gesture sets for pen and mid-air input and pen and multi-touch input with users in a lab environment. Overall, our results suggest that pen and mid-air input should be offered to complement traditional pen and multi-touch input on tablets. We illustrate the final user-defined gestures set for pen and mid-air input and discuss how user preferences of mid-air gestures over touch gestures seem to depend on the complexity of operations and the need of additional menus on the screen.","Title: Towards a Multimedia Knowledge-Based Agent with Social Competence and Human Interaction Capabilities.\nYear: 2016\n\nAbstract: We present work in progress on an intelligent embodied conversation agent in the basic care and healthcare domain. In contrast to most of the existing agents, the presented agent is aimed to have linguistic cultural, social and emotional competence needed to interact with elderly and migrants. It is composed of an ontology-based and reasoning-driven dialogue manager, multimodal communication analysis and generation modules and a search engine for the retrieval of multimedia background content from the web needed for conducting a conversation on a given topic.","Title: Touch or Talk?: Comparing Social Robots and Tablet PCs for an Elderly Assistant Recommender System.\nYear: 2017\n\nAbstract: This work is targeted towards the development of a recommender system that fosters the well-being of elderly people in their domestic environment. Since seniors can have a rather high barrier of using newer technologies, the interaction device utilized in such a system has to be selected carefully. This paper compares an anthropomorphic presentation of recommendations by a social robot with a graphical presentation on a tablet PC in terms of the perceived usability, the users' experience and the system's persuasion.","Title: Real-Time Robot Personality Adaptation based on Reinforcement Learning and Social Signals.\nYear: 2017\n\nAbstract: Recent findings in Human-Robot Interaction (HRI) indicate that the adaptation of a robot's behaviors to the human's personality profile makes interaction more engaging, but also that it depends on the task context whether a similar or opposing robot personality is preferred. This late breaking report presents our ongoing work on an approach using Reinforcement Learning and social signals for figuring out and adapting to the human preferences, i.e. desired personality profile. Our scenario involves a \\\"Reeti\\\" robot in the role of a story teller talking about the main characters in the novel \\\"Alice's Adventures in Wonderland\\\" by generating descriptions with varying degree of introversion/extraversion. The learning process is running in real-time during the interaction and allows for simultaneous adaptation without explicitly asking the user about its preferences.","Title: Towards a Gamified Recommender System for the Elderly.\nYear: 2017\n\nAbstract: Starting from our previous work on a digital picture frame - the CARE system - that interleaves a picture display mode with a recommender mode to promote a healthy life-style and to increase well-being of elderly people, this paper investigates the use of gamification as a means to increase user appreciation of the CARE system. To this end, we arranged two co-design workshops with peer-groups of senior citizens. We report on outcomes of the workshops and draw conclusions for a gamified version of CARE.","Title: Development of a Multi-Device Nutrition Logging Prototype Including a Smartscale.\nYear: 2017\n\nAbstract: In this work we present a portable system for nutrition logging that integrates multiple devices and modalities in order to facilitate food and drink tracking. The system consists of a smartphone, a smartwatch and a smartscale that can be combined flexibly by users depending on the current situation and their personal needs. Based on a requirement analysis, we present the rationale behind the design and implementation of our food and drink logger. We also report the preliminary results of an in-situ study we conducted in order to explore the potential benefits and challenges of a multi-device approach to nutrition tracking in daily life settings.","Title: The Senseemotion Database: A Multimodal Database For The Development And Systematic Validation Of An Automatic Pain- And Emotion-Recognition System\nYear: 2016\n\nAbstract: In our modern industrial society the group of the older (generation 65+) is constantly growing. Many subjects of this group are severely affected by their health and are suffering from disability and pain. The problem with chronic illness and pain is that it lowers the patient's quality of life, and therefore accurate pain assessment is needed to facilitate effective pain management and treatment. In the future, automatic pain monitoring may enable health care professionals to assess and manage pain in a more and more objective way. To this end, the goal of our SenseEmotion project is to develop automatic pain- and emotion-recognition systems for successful assessment and effective personalized management of pain, particularly for the generation 65+. In this paper the recently created SenseEmotion Database for pain-vs. emotion-recognition is presented. Data of 45 healthy subjects is collected to this database. For each subject approximately 30 min of multimodal sensory data has been recorded. For a comprehensive understanding of pain and affect three rather different modalities of data are included in this study: biopotentials, camera images of the facial region, and, for the first time, audio signals. Heat stimulation is applied to elicit pain, and affective image stimuli accompanied by sound stimuli are used for the elicitation of emotional states.","Title: KRISTINA: A Knowledge-Based Virtual Conversation Agent.\nYear: 2017\n\nAbstract: We present an intelligent embodied conversation agent with linguistic, social and emotional competence. Unlike the vast majority of the state-of-the-art conversation agents, the proposed agent is constructed around an ontology-based knowledge model that allows for flexible reasoning-driven dialogue planning, instead of using predefined dialogue scripts. It is further complemented by multimodal communication analysis and generation modules and a search engine for the retrieval of multimedia background content from the web needed for conducting a conversation on a given topic. The evaluation of the 1st prototype of the agent shows a high degree of acceptance of the agent by the users with respect to its trustworthiness, naturalness, etc. The individual technologies are being further improved in the 2nd prototype.","Title: Co-Designing a Recommender System for the Elderly.\nYear: 2017\n\nAbstract: To promote a healthy life-style and to increase well-being of elderly people, we have extended a digital picture frame - the CARE system - that interleaves a picture display mode with a recommender mode. In recommender mode, CARE encourages its users to engage in physical and mental training activities. The success of such a system essentially depends on the extent to which given recommendations are followed. The current paper investigates in how far rewarding schemes as known from computer games could be deployed in order to increase user appreciation of the CARE system. To this end, we prepared and ran a co-design workshop with a peer-group of senior citizens. Finally, we draw conclusions that will guide our work towards a gamified version of CARE.","Title: Exploring Opportunistic Ambient Notifications in the Smart Home to Enhance Quality of Live.\nYear: 2017\n\nAbstract: Smart home technology became more and more widespread within recent years. They aim to make life easier and taking over unwanted tasks. In traditional homes, it is often not clear whether all windows and doors of a house are closed before inhabitants leave the home or go to sleep. However, this can be easily addressed by smart homes. We present a system based on opportunistically located ambient lights that assist inhabitants of a smart home in answering this question. In this paper, we show the concept of our system and the inhabitant-centered design process behind the development. The system was installed in a one-family smart home. We report on insights gained through data collected from this deployment over a period of six months. Within interviews, we found that the ambient light system gave inhabitants a more confident feeling about open doors/windows.","Title: Temporal Visualization of Energy Consumption Loads Using Time-Tone\nYear: 2017\n\nAbstract: Feedback plays an important role in assisting users to better understand their energy consumption behaviour. This is particularly true when users want to change their behaviour in order to reduce their energy consumption, and to manage their usage more effectively so as to avoid putting unnecessary load on energy providers. This paper presents the time-tone visualization, which aims to assist users by displaying variations in energy consumption by different categories of household devices over time, and their respective contributions to the total energy usage load. A user study conducted to compare time-tone against area-charts shows that although the two visualizations are comparable, time-tone is more effective for cases where there are large variations in energy usage loads.","Title: The NoXi database: multimodal recordings of mediated novice-expert interactions.\nYear: 2017\n\nAbstract: We present a novel multi-lingual database of natural dyadic novice-expert interactions, named NoXi, featuring screen-mediated dyadic human interactions in the context of information exchange and retrieval. NoXi is designed to provide spontaneous interactions with emphasis on adaptive behaviors and unexpected situations (e.g. conversational interruptions). A rich set of audio-visual data, as well as continuous and discrete annotations are publicly available through a web interface. Descriptors include low level social signals (e.g. gestures, smiles), functional descriptors (e.g. turn-taking, dialogue acts) and interaction descriptors (e.g. engagement, interest, and fluidity).","Title: Pre-touch proxemics: moving the design space of touch targets from still graphics towards proxemic behaviors.\nYear: 2017\n\nAbstract: Proxemic touch targets continuously change in relation to a user's hand in mid-air before a physical touch occurs. Previous work has, for example shown that expanding targets are capable to improve target acquisition performance on touch interfaces. However, it is unclear how proxemic touch targets influence user experience (UX) in a broader sense, including hedonic qualities. Towards closing this research gap the paper reports on two user studies. The first study is a qualitative study with five experts, providing in-depth insights on a variety of change-types (e.g., size, form, color) and how they, for example, influence perceived functional and aesthetic qualities of proxemic touch targets. A follow-up user study with 36 participants explores the UX of a proxemic touch target compared to non-proximal versions of the same target. The results highlight a positive significant effect of the proxemic design on both pragmatic and hedonic qualities.","Title: Automatic Detection of Visual Search for the Elderly using Eye and Head Tracking Data.\nYear: 2017\n\nAbstract: With increasing age we often find ourselves in situations where we search for certain items, such as keys or wallets, but cannot remember where we left them before. Since finding these objects usually results in a lengthy and frustrating process, we propose an approach for the automatic detection of visual search for older adults to identify the point in time when the users need assistance. In order to collect the necessary sensor data for the recognition of visual search, we develop a completely mobile eye and head tracking device specifically tailored to the requirements of older adults. Using this device, we conduct a user study with 30 participants aged between 65 and 80 years (\\(avg = 71.7,\\) 50% female) to collect training and test data. During the study, each participant is asked to perform several activities including the visual search for objects in a real-world setting. We use the recorded data to train a support vector machine (SVM) classifier and achieve a recognition rate of 97.55% with the leave-one-user-out evaluation method. The results indicate the feasibility of an approach towards the automatic detection of visual search in the wild.","Title: Adapting a Robot's linguistic style based on socially-aware reinforcement learning\nYear: 2017\n\nAbstract: When looking at Socially Interactive Robots, adaptation to the user's preferences plays an important role in today's Human-Robot Interaction to keep interaction interesting and engaging over a long period of time. Findings indicate an increase in user engagement for robots with adaptive behavior and personality, but also that it depends on the task context whether a similar or opposing robot personality is preferred. We present an approach based on Reinforcement Learning, which gets its reward directly from social signals in real-time during the interaction, to quickly learn about and dynamically address individual human preferences. Our scenario involves a Reeti robot in the role of a story teller talking about the main characters in the novel “Alice's Adventures in Wonderland” by generating descriptions with varying degree of introversion/extraversion. After initial simulation results, an interactive prototype is presented which allows to explore the learning process adapting to the human interaction partner's engagement.","Title: Development of a mobile multi-device nutrition logger.\nYear: 2017\n\nAbstract: In this paper we present a mobile system for nutrition logging which integrates multiple devices and modalities to facilitate food and drink tracking. The user is free to decide in each situation to use the most appropriate device combination out of a smartphone, smartwatch and smartscale. We describe the design and implementation of our system which is based on a requirements analysis. Finally, first results of a preliminary in-situ study with the prototype are reported giving first hints about the benefits and challenges of this multi-device approach in daily life scenarios.","Title: Applying Cooperative Machine Learning to Speed Up the Annotation of Social Signals in Large Multi-modal Corpora.\nYear: 2018\n\nAbstract: Scientific disciplines, such as Behavioural Psychology, Anthropology and recently Social Signal Processing are concerned with the systematic exploration of human behaviour. A typical work-flow includes the manual annotation (also called coding) of social signals in multi-modal corpora of considerable size. For the involved annotators this defines an exhausting and time-consuming task. In the article at hand we present a novel method and also provide the tools to speed up the coding procedure. To this end, we suggest and evaluate the use of Cooperative Machine Learning (CML) techniques to reduce manual labelling efforts by combining the power of computational capabilities and human intelligence. The proposed CML strategy starts with a small number of labelled instances and concentrates on predicting local parts first. Afterwards, a session-independent classification model is created to finish the remaining parts of the database. Confidence values are computed to guide the manual inspection and correction of the predictions. To bring the proposed approach into application we introduce NOVA - an open-source tool for collaborative and machine-aided annotations. In particular, it gives labellers immediate access to CML strategies and directly provides visual feedback on the results. Our experiments show that the proposed method has the potential to significantly reduce human labelling efforts.","Title: Designing Systems to Augment Social Interactions.\nYear: 2018\n\nAbstract: Thanks to the rapid advancement of mobile and wearable technologies over the past decade, a new shift in social skills training lies ahead that will allow users to continuously monitor and improve their social behavior during actual social interactions. At the same time, despite the demonstrated effectiveness of social augmentation, researchers must address several limitations.","Title: Simulation Sickness Evaluation While Using A Fully Autonomous Car In A Head Mounted Display Virtual Environment\nYear: 2018\n\nAbstract: Simulation sickness is a condition of physiological discomfort felt during or after exposure to a virtual environment. A virtual environment can be accessed through a head mounted display which provides the user with an entrance to the virtual world. The onset of simulation sickness is a main disadvantage of virtual reality (VR) systems. The proof-of-concept presented in this paper aims to provide new insights into development and evaluation of a VR driving simulation based on consumer electronics devices and a 3 Degrees-of-Freedom (3 DOF) motion platform. A small sample (n = 9) driving simulator pre-study with within-subjects design was conducted to explore simulation sickness outbreak, sense of presence and physiological responses induced by autonomous driving in a dynamic and static driving simulation. The preliminary findings show that users experienced no substantial simulation sickness while using an autonomous car when the VR simulation included a motion platform. This study is the basis for more extensive research in the future. Future studies will include more participants and investigate more factors that contribute to or mitigate the effects of simulation sickness.","Title: Marssi: Model Of Appraisal, Regulation, And Social Signal Interpretation\nYear: 2018\n\nAbstract: Understanding emotions of others requires a theory of mind approach providing knowledge of internal appraisal and regulation processes of emotions. Multi-modal social signal classification is insufficient for understanding emotional expressions. Mainly, because many communicative, emotional expressions are not directly related to internal emotional states. Moreover, the recognition of the expression's direction is neglected so far. Even if social signals reveal emotional aspects, the recognition with signal classifiers cannot explain internal appraisal or regulation processes. Using that information is one approach for building cognitive empathic agents with the ability to address observations and motives in an empathic dialogue. In this paper, we introduce a computational model of user emotions for empathic agents. It combines a simulation of appraisal and regulation processes with a social signal interpretation taking directions of expressions into account. Our evaluation shows that social signal sequences can be related to emotion regulation processes. Their recognition and using appraisal and regulation knowledge enables our agent to react empathically.","Title: Multiplex Network Structure Enhances The Role Of Generalized Reciprocity In Promoting Cooperation\nYear: 2018\n\nAbstract: In multi-agent systems, cooperative behavior is largely determined by the network structure which dictates the interactions among neighboring agents. These interactions often exhibit multidimensional features, either as relationships of different types or temporal dynamics, both of which may be modeled as a \"multiplex\" network. Against this background, here we advance the research on cooperation models inspired by generalized reciprocity, a simple pay-it-forward behavioral mechanism, by considering a multidimensional networked society. Our results reveal that a multiplex network structure can act as an enhancer of the role of generalized reciprocity in promoting cooperation by acting as a latent support, even when the parameters in some of the separate network dimensions suggest otherwise (i.e. favor defection). As a result, generalized reciprocity forces the cooperative contributions of the individual agents to concentrate in the dimension which is most favorable for the existence of cooperation.","Title: The SSJ Framework: Augmenting Social Interactions Using Mobile Signal Processing and Live Feedback.\nYear: 2018\n\nAbstract: Thanks to recent technological advancements, powerful computers and versatile sensor arrays can now be integrated in small wearable devices. This paper introduces the Android framework SSJ, which makes use of such devices to augment social interaction. To this end, sensor data is first used to analyse the useru0027s behaviour in realtime. Based on the analysis, SSJ then sends live multimodal feedback to the user while they participate in a social interaction. With the help of advanced feedback strategies, SSJ can minimize the disruption of the social interaction while still helping the user improve the quality of their behaviour.","Title: EVA: A Multimodal Argumentative Dialogue System.\nYear: 2018\n\nAbstract: This work introduces EVA, a multimodal argumentative Dialogue System that is capable of discussing controversial topics with the user. The interaction is structured as an argument game in which the user and the system select respective moves in order to convince their opponent. EVA's response is presented as a natural language utterance by a virtual agent that supports the respective content using characteristic gestures and mimic.","Title: How to Shape the Humor of a Robot - Social Behavior Adaptation Based on Reinforcement Learning.\nYear: 2018\n\nAbstract: A shared sense of humor can result in positive feelings associated with amusement, laughter, and moments of bonding. If robotic companions could acquire their human counterparts' sense of humor in an unobtrusive manner, they could improve their skills of engagement. In order to explore this assumption, we have developed a dynamic user modeling approach based on Reinforcement Learning, which allows a robot to analyze a person's reaction while it tells jokes and continuously adapts its sense of humor. We evaluated our approach in a test scenario with a Reeti robot acting as an entertainer and telling different types of jokes. The exemplary adaptation process is accomplished only by using the audience's vocal laughs and visual smiles, but no other form of explicit feedback. We report on results of a user study with 24 participants, comparing our approach to a baseline condition (with a non-learning version of the robot) and conclude by providing limitations and implications of our approach in detail.","Title: Gazeover - Exploring the UX of Gaze-triggered Affordance Communication for GUI Elements.\nYear: 2018\n\nAbstract: The user experience (UX) of graphical user interfaces (GUIs) often depends on how clearly visual designs communicate/signify \"affordances\", such as if an element on the screen can be pushed, dragged, or rotated. Especially for novice users figuring out the complexity of a new interface can be cumbersome. In the \"past\" era of mouse-based interaction mouseover effects were successfully utilized to trigger a variety of assistance, and help users in exploring interface elements without causing unintended interactions and associated negative experiences. Today's GUIs are increasingly designed for touch and lack a method similiar to mouseover to help (novice) users to get acquainted with interface elements. In order to address this issue, we have studied gazeover, as a technique for triggering \"help or guidance\" when a user's gaze is over an interactive element, which we believe is suitable for today's touch interfaces. We report on a user study comparing pragmatic and hedonic qualities of gazeover and mouseover, which showed significant higher ratings in hedonic quality for the gazeover technique. We conclude by discussing limitations and implications of our findings.","Title: Pen + Mid-Air Gestures: Eliciting Contextual Gestures.\nYear: 2018\n\nAbstract: Combining mid-air gestures with pen input for bi-manual input on tablets has been reported as an alternative and attractive input technique in drawing applications. Previous work has also argued that mid-air gestural input can cause discomfort and arm fatigue over time, which can be addressed in a desktop setting by allowing users to gesture in alternative restful arm positions (e.g., elbow rests on desk). However, it is unclear if and how gesture preferences and gesture designs would be different for alternative arm positions. In order to inquire these research question we report on a user and choice based gesture elicitation study in which 10 participants designed gestures for different arm positions. We provide an in-depth qualitative analysis and detailed categorization of gestures, discussing commonalities and differences in the gesture sets based on a \"think aloud\" protocol, video recordings, and self-reports on user preferences.","Title: Decision-Theoretic Personality-Based Reasoning About Turn-Taking Conflicts\nYear: 2018\n\nAbstract: This paper outlines the use of an influence diagram for modeling turn-taking timing. In contrast to related works, our model focuses on an agent's personality and attitude towards the conversation partner. We also describe how this model is implemented in a first prototype application.","Title: Enabling Privacy With Transfer Learning For Image Classification Dnns On Mobile Devices\nYear: 2018\n\nAbstract: More people could benefit of Machine Learning (ML) as an increasingly important technology and service, if state-of-the-art ML techniques with training capability were accessible on personal devices. To this end, we report details on how to deploy Tensor-Flow on off-the-shelf mobile and embedded devices and retrain current deep neural networks for image recognition on-device. Our motivation is to both grant privacy and allow users to efficiently personalize image classifiers for their own needs and purposes, and thus contribute towards turning ML into a \"social good\", which benefits the largest number of people in the greatest possible way.","Title: PARLEY: a transparent virtual social agent training interface\nYear: 2019\n\nAbstract: In this demo, we present PARLEY, an interactive system to train difficult social situations in a safe environment with a Virtual Agent. The system realizes different phenomena studied by psychology research that are known to create a natural interaction. Moreover, we include an open learner model to ensure an explainable user experience.","Title: Emotion recognition using physiological and speech signal in short-term observation\nYear: 2006\n\nAbstract: Recently, there has been a significant amount of work on the recognition of emotions from visual, verbal or physiological information. Most approaches to emotion recognition so far concentrate, however, on a single modality while work on the integration of multimodal information, in particular on fusing physiological signals with verbal or visual data, is scarce. In this paper, we analyze various methods for fusing physiological and vocal information and compare the recognition results of the bimodal recognition approach with the results of the unimodal approach.","Title: The Assisted User-Centred Generation and Evaluation of Pervasive Interfaces\nYear: 2009\n\nAbstract: The usability of a pervasive interface is crucial because it is a quality criterion which can determine about the success or the failure of a product. The application of the user-centred design is a possibility to reach a good design. However, this process requires combined knowledge of software and usability engineering. A lack of these skills can cause long development times and additional costs as well as badly usable interfaces. We address these problems and support interface developers with a tool-based assistance which reduces the required programming and interface design skills of the developers in order to more efficiently conduct the user-centred design. In this paper we describe this tool-based assistance for the user-centred generation and evaluation of pervasive interfaces for mobile phones as well as its evaluation.","Title: Integrating VR-Authoring and context sensing: towards the creation of context-aware stories\nYear: 2006\n\nAbstract: Recent progress in the area of sensor technology has enabled the development of context-aware systems that are able to dynamically adapt their behaviours to the current situation and the individual user. In this paper, we present a framework for a new generation of context-sensitive stories that dynamically adapt to changing environmental conditions and user states. The framework combines approaches to interactive storytelling with work on context toolkits that foster the rapid prototyping of context-aware applications.","Title: What Would You Do in Their Shoes? Experiencing Different Perspectives in an Interactive Drama for Multiple Users\nYear: 2009\n\nAbstract: Following the idea of improvisational theater, we built a multi-agent system where multiple users can experience an interactive drama from different perspectives. Depending on the roles that the users are given in advance, the situation is perceived in various ways and interaction possibilities are directed according to the assigned role. The computer-controlled agents' behavior needs to be highly reactive in order to allow for flexibility in the conversational flow of the structured interactive narrative. In this paper, we describe a system architecture that allows multi-user participation as well as distributed behavior planning for multiple agents.","Title: Usage and recognition of finger orientation for multi-touch tabletop interaction\nYear: 2011\n\nAbstract: Building on the observation that finger orientation is an inherent part of human's interaction in the real world, exploiting finger orientation for multitouch tabletop interaction would facilitate more natural interaction techniques. We motivate this by means of examples where the finger orientation improves or enriches interaction. Afterwards, we present a simple and fast approach to detect the finger orientation reliably for multi-touch tabletop interaction. The steps involved are computationally cheap and therefore suit the needs of tracking software operating under time-critical conditions. We show that the presented approach enables the detection of finger orientation also for fingers that touch the tabletop surface only slightly. Further, recognition rates on real data gained from the camera within a multi-touch tabletop are presented in order to give a measure for the precision and reliability of the presented approach.","Title: Infected Phonemes: How A Cold Impairs Speech On A Phonetic Level\nYear: 2017\n\nAbstract: The realization of language through vocal sounds involves a complex interplay between the lungs, the vocal cords, and a series of resonant chambers (e.g. mouth and nasal cavities). Due to their connection to the outside world. these body parts are popular spots for viruses and bacteria to enter the human organism. Affected people may suffer from an upper respiratory tract infection (URTIC) and consequently their voice often sounds breathy, raspy or sniffly. In this paper, we investigate the audible effects of a cold on a phonetic level. Results on a German corpus show that the articulation of consonants is more impaired than that of vowels. Surprisingly, nasal sounds do not follow this trend in our experiments. We finally try to predict a speaker's health condition by fusing decisions we derive from single phonemes. The presented work is part of the INTERSPEECH 2017 Computational Paralinguistics Challenge.","Title: Of Smarthomes, IoT Plants, and Implicit Interaction Design\nYear: 2019\n\nAbstract: There seems to be a danger to carelessly replace routine tasks in homes through automation with IoT-technology. But since routines, such as watering houseplants also have positive influences on inhabitants' wellbeing, they should be transformed through carefully performed designs. To this end, an attempt to use technology for augmenting a set of houseplants' non-verbal communication capabilities is presented. First, we describe in detail how implicit interactions have been designed to support inhabitants in watering their plants through meaningful interactions. Then, we report on a field study with 24 participants, comparing two alternative design implementations based on contrasting embodied interaction technologies (i.e., augmented reality and embedded computing technology). The study results highlight shortcomings of today's smartphone mediated augmented reality compared to physical interface alternatives, considering measurements of perceived attractiveness and expected effects on determinants of wellbeing, and discusses potentials of combining both modalities for future solutions.","Title: Real-Time Adaptation Of A Robotic Joke Teller Based On Human Social Signals\nYear: 2018\n\nAbstract: Humor is an essential element of human-human communication. Consequently, robots in the role of companions should exploit its potential as well to make interactions more enjoyable. Using a robot as an entertainer requires finding out what kind of humor its audience prefers. However, it is a challenging task for a social robot to learn what users prefer without bothering them by repeatedly asking questions. In this paper, we present an approach based on Reinforcement Learning that enables a robot to continuously adapt to the users' humor preferences without requiring them to explicitly provide feedback. Instead, we designed the robot to analyze the user's ideomotor social cues. We evaluated our approach in a scenario involving a Reeti robot acting as an entertainer. In this role, it is telling different types of jokes, (possibly) underlining its performance with grimaces and sounds. The adaptation process is accomplished only by using the audience's vocal laughs and visual smiles, but no other form of explicit feedback.","Title: Providing Life-Style-Intervention to Improve Well-Being of Elderly People.\nYear: 2018\n\nAbstract: We report on a user-centered approach towards the development of an augmented digital picture frame - called \"CARE\" - for senior users with the aim to improve their general well-being. The central idea is to interleave the display of pictures with the provision of recommendations of activities that seniors may perform in addition to their ordinary daily routines. We also report on our attempt to encourage durable use of the CARE system by introducing reward schemes for recommended activities. Feedback from users suggests that reward schemes should be made individually configurable.","Title: IEEE Transactions on Affective Computing–Entering the 10th Year of Publication\nYear: 2019\n\nAbstract: AbstractPresents the introductory editorial for this issue of the publication.","Title: Insights on usability and user feedback for an assistive robotic health companion with adaptive linguistic style\nYear: 2019\n\nAbstract: Socially assistive robots help the human in everyday tasks. In particular, they can also provide assistance with regard to health and wellbeing, which is an important opportunity to support the independence of the elderly. Since spoken language often carries the essential information, the robot's verbal communication style is of special interest. In order to explore individual user's preferences with regard to the robot's linguistic style we built an autonomous, assistive health companion. It is operated with a custom hardware control panel and offers games, jokes, health-related recommendations, applications for information retrieval and communication. This paper reports on insights from the in-situ user study with regard to the system's usability and participants' feedback.","Title: Adaptive linguistic style for an assistive robotic health companion based on explicit human feedback\nYear: 2019\n\nAbstract: In the future, an increasing amount of social robots will be found in our domestic environments to support and facilitate everyday life. Especially in the context of assistive, health-related support, more and more robotic products are on the way to the consumer market. While one can observe that many commercial efforts are put into the visual appearance, embodiment, motion and sound of companion robots, this paper focuses on the robot's conversational skills. We investigate how to adapt the robot's linguistic style to the individual user's preferences. This includes two forms of robot persona in the context of information retrieval tasks and games, as well as politeness with regard to recommendations. Therefore, we present an autonomous companion robot, which adapts its spoken language based on explicit human feedback. It provides several functionalities for information retrieval, reminders, communication and entertainment as well as health-related recommendations. Results of the in-situ study with elderly participants indicate that human preferences vary with regard to the robot's employed politeness strategies. Furthermore, the participants preferred assistant persona over companion persona in the information retrieval context.","Title: Stress Annotations from Older Adults - Exploring the Foundations for Mobile ML-Based Health Assistance\nYear: 2019\n\nAbstract: The number of new mobile and wearable technologies with built-in sensors for quantifying every aspect of our lives is increasing. Consequently, new data sources and opportunities arise for the development of machine learning (ML) models and their applications. In this paper, we report on a four weeks field study with 16 older adults, aged between 66 and 81 years (50% female), who were asked to provide stress-related experience samples in different modalities, including paper-based diaries and data collected with the help of a wearable (i.e., a Microsoft Band 2). We provide insights into participants' stress annotation behavior, report on a detailed analysis of the recorded data and the resulting implications regarding the annotation of stressful situations by older adults, discuss how mobile annotation technology can benefit from the synergies with traditional methods and argue why we believe that appropriate annotation techniques are the basis to benefit individually from future powerful machine learning models.","Title: Emotion Recognition Based Preference Modelling in Argumentative Dialogue Systems\nYear: 2019\n\nAbstract: Within this work, we present an approach to model the opinion of a human towards a specific topic in a fine-grained way by using weighted bipolar argumentation graphs. In addition, we discuss how the therefore required rating of related aspects can be collected by means of emotion recognition techniques and discuss an application scenario based on the state-of-the-art Argumentative Dialogue System EVA in which the proposed techniques can be applied.","Title: Irony Man: Augmenting a Social Robot with the Ability to Use Irony in Multimodal Communication with Humans\nYear: 2019\n\nAbstract: Interpersonal communication is often full of irony and irony related humor, which can shape the quality of a conversation and how conversation partners perceive each other. If social robots were able to integrate irony in their communication style, their human conversation partners might perceive them as more natural, credible, and ultimately more attractive and acceptable. In order to explore this assumption, we first describe an approach to transform non-ironic inputs on-the-fly into multimodal ironic utterances. Irony markers are used to adapt language, prosody and facial expression. We argue that doing this allows to dynamically enrich a robot's spoken language with an expression of socially intelligent behavior. We then demonstrate the feasibility of our approach by reporting on a user study, which compares an ironic version of a robot with a non-ironic version of the same robot in a small talk dialog scenario. Results show that participants are indeed able to correctly identify a robot's use of irony and that a better user experience is associated with an ironic robot version. This is an important step for dynamically shaping a robot's personality and humor, and to increase perceived social intelligence.","Title: What If I Speak Now?: A Decision-Theoretic Approach to Personality-Based Turn-Taking\nYear: 2019\n\nAbstract: Embodied conversational agents, which are increasingly prevalent in our society, require turn-taking mechanisms that not only generate fluent conversations but are also consistent with the personality and interpersonal stance required in the given context. We present a decision-theoretic approach for deriving the turn-taking behavior of such an agent from the personality it is meant to convey. For this we gathered relevant theories from psychology and communications research, as well as related systems employing utility-based reasoning. On this basis we describe the construction of an influence diagram which decides between acting and waiting based on those actions' expected utility for the agent's personality-related interaction goals. To test our approach, we integrated our model into an application which simulates conversations between two virtual characters. We then evaluated our prototype by presenting videos of those conversations in an online survey. Our results confirmed that differences in an agent's speaking behavior, generated from different Extraversion configurations in our model, lead to the intended perceptions of its Extraversion, Agreeableness and Status.","Title: Designing a Mobile Social and Vocational Reintegration Assistant for Burn-out Outpatient Treatment.\nYear: 2019\n\nAbstract: Using Social Agents as health-care assistants or trainers is one focus area of IVA research. While their use as physical health-care agents is well established, their employment in the field of psychotherapeutic care comes with daunting challenges. This paper presents our mobile Social Agent EmmA in the role of a vocational reintegration assistant for burn-out outpatient treatment. We follow a typical participatory design approach including experts and patients in order to address requirements from both sides. Since the success of such treatments is related to a patients emotion regulation capabilities, we employ a real-time social signal interpretation together with a computational simulation of emotion regulation that influences the agent's social behavior as well as the situational selection of verbal treatment strategies. Overall, our interdisciplinary approach enables a novel integrative concept for Social Agents as assistants for burn-out patients.","Title: Teaching Ethics as a Creative Subject: Ideas From an Interdisciplinary Workshop\nYear: 2021\n\nAbstract: Designers and developers have great power and they are often not aware of it. The decisions they make in system design and theway they implement algorithms inevitably encode ethical values. We propose using “Dark Scenarios” as a teaching tool to make ethical issues and value sensitive design a creative process that fits the mindset of designers and developers.","Title: Do You Mind if I Pass Through? Studying the Appropriate Robot Behavior when Traversing two Conversing People in a Hallway Setting*\nYear: 2021\n\nAbstract: Several works highlight how robots can navigate in a socially-aware manner by respecting and avoiding people’s personal spaces. But how should the robot act when there is no way around a group of persons? In this work, we explore this question by comparing three different ways to cross two conversing people in a hallway environment. In an online study with 135 participants, users rated the robot’s...","Title: A human-driven control architecture for promoting good mental health in collaborative robot scenarios\nYear: 2021\n\nAbstract: This paper introduces the control architecture of a platform aimed at promoting good mental health for workers interacting with collaborative robots (cobots). The platform aim is to render industrial production cells capable of automatically adapting their behavior in order to improve the operator’s quality of experience and level of engagement and to minimize his/her psychological strain. In orde...","Title: Dynamic Difficulty Adjustment in Virtual Reality Exergames through Experience-driven Procedural Content Generation.\nYear: 2021\n\nAbstract: Virtual Reality (VR) games that feature physical activities have been shown to increase players' motivation to do physical exercise. However, for such exercises to have a positive healthcare effect, they have to be repeated several times a week. To maintain player motivation over longer periods of time, games often employ Dynamic Difficulty Adjustment (DDA) to adapt the game's challenge according to the player's capabilities. For exercise games, this is mostly done by tuning specific in-game parameters like the speed of objects. In this work, we propose to use experience-driven Procedural Content Generation for DDA in VR exercise games by procedurally generating levels that match the player's current capabilities. Not only finetuning specific parameters but creating completely new levels has the potential to decrease repetition over longer time periods and allows for the simultaneous adaptation of the cognitive and physical challenge of the exergame. As a proof-of-concept, we implement an initial prototype in which the player must traverse a maze that includes several exercise rooms, whereby the generation of the maze is realized by a neural network. Passing those exercise rooms requires the player to perform physical activities. To match the player's capabilities, we use Deep Reinforcement Learning to adjust the structure of the maze and to decide which exercise rooms to include in the maze. We evaluate our prototype in an exploratory user study utilizing both biodata and subjective questionnaires.","Title: To Move or Not to Move? Social Acceptability of Robot Proxemics Behavior Depending on User Emotion\nYear: 2021\n\nAbstract: Various works show that proxemics occupies an important role in human-robot interaction and that appropriate proxemic interaction depends on many characteristics of humans and robots. However, there is none that shows the relationship between an emotional state expressed by a user and a proxemic reaction of the robot to it, in a social interaction between these interactants. In the current experiment (N = 82), we investigate this using an online study in which we examine which proxemic response (i.e., approaching, not moving, moving away) to a person's expressed emotional state (i.e., anger, fear, disgust, surprise, sadness, joy) is perceived as appropriate. The quantitative and qualitative data collected suggests that the robot's approach was considered appropriate for the expressed fear, sadness, and joy, whereas moving away was perceived as inappropriate in most scenarios. Further exploratory findings underline the importance of appropriate nonverbal behavior on the perception of the robot.","Title: Multi-Modal Pain Intensity Recognition Based on the SenseEmotion Database\nYear: 2021\n\nAbstract: The subjective nature of pain makes it a very challenging phenomenon to assess. Most of the current pain assessment approaches rely on an individual’s ability to recognise and report an observed pain episode. However, pain perception and expression are affected by numerous factors ranging from personality traits to physical and psychological health state. Hence, several approaches have been propos...","Title: Socially Interactive Artificial Intelligence: Past, Present and Future\nYear: 2021\n\nAbstract: ABSTRACT Socially interactive artificial agents are no longer mere fiction. For many, they are already part of everyday life. Due to technical advances in multimodal behavior analysis and synthesis, the asymmetry of communication between machines and humans is dissolving. Consequently, the interaction with robots and virtual characters has become more intuitive and natural, particularly for everyday users. Nevertheless, there is still some work to be done until artificial agents are able to smoothly interact with people over more extended periods in their homes and to cope with unforeseen situations. In my talk, I will recall my journey into the field of socially interactive Artificial Intelligence starting in the 90ies with the development of the Personalized Plan-Based Presenter (in short, the PPP Persona [1]). This cartoon character explained technical devices to users by combining speech, gestures, and facial expressions. We quickly realized that we had to equip such characters with a certain amount of social and emotional intelligence to keep users engaged over a more extended period. Furthermore, it became clear that creating such agents is not a job that can be done by computer scientists alone. In collaboration with social and medical sciences, dramaturgy, and media art colleagues, we developed a wide range of applications with socially interactive characters or robots over the past years, including art and entertainment [2], cultural training [5]and social coaching [3], and more recently, personal wellbeing and health [4]. In my talk, I will describe various computational methods to implement socially interactive behaviors in artificial agents. Besides analytic methods informed by theories from the cognitive and social sciences, I will discuss empirical approaches that enable an artificial agent to learn socially interactive behaviors from recordings of human-human interactions or life interactions with human interlocutors. I will highlight opportunities and challenges that arise from neural behavior generation approaches that promise to achieve the next level of human-likeness in virtual agents and social robots. Finally, I will share lessons we learnt during the development of socially interactive agents. To benefit users, we do not just have to work on technical solutions, but go beyond disciplinary boundaries to encompass ethical, legal, and social implications of employing such agents.","Title: MultiMediate: Multi-modal Group Behaviour Analysis for Artificial Mediation\nYear: 2021\n\nAbstract: ABSTRACTArtificial mediators are promising to support human group conversations but at present their abilities are limited by insufficient progress in group behaviour analysis. The MultiMediate challenge addresses, for the first time, two fundamental group behaviour analysis tasks in well-defined conditions: eye contact detection and next speaker prediction. For training and evaluation, MultiMediate makes use of the MPIIGroup Interaction dataset consisting of 22 three- to four-person discussions as well as of an unpublished test set of six additional discussions. This paper describes the MultiMediate challenge and presents the challenge dataset including novel fine-grained speaking annotations that were collected for the purpose of MultiMediate. Furthermore, we present baseline approaches and ablation studies for both challenge tasks","Title: Social Signals and Multimedia: Past, Present, Future\nYear: 2021\n\nAbstract: ABSTRACTThe rising popularity of Artificial Intelligence (AI) has brought considerable public interest as well faster and more direct transfer of research ideas into practice. One of the aspects of AI that still trails behind considerably is the role of machines in interpreting, enhancing, modeling, generating, and influencing social behavior. Such behavior is captured as social signals, usually by sensors recording multiple modalities, making it classic multimedia data. Such behavior can also be generated by an AI system when interacting with humans. Using AI techniques in combination with multimedia data can be used to pursue multiple goals, two of which are high-lighted here. First, supporting people during social interactions and helping them to fulfil their social needs either actively or passively.Second, improving our understanding of how people collaborate, build relationships, and process self identity. Despite the rise of fields such as Social Signal Processing, a similar panel organised at ACM Multimedia 2014, and an area on social and emotional signal sat the ACM MM since 2014, we argue that we have yet to truly fulfil the potential of the combining social signals and multimedia. This panel asks where we have come far enough and what remaining challenges there are in light of recent global events.","Title: Intelligent Signal Processing for Affective Computing [From the Guest Editors]\nYear: 2021\n\nAbstract: Affective computing is computing that relates to, arises from, or deliberately influences emotion or other affective phenomena. Human emotion and affect in general are fundamental to human experience, influencing cognition, perception, and everyday tasks such as learning and communication, but are also fundamental to human health and well-being. The field of affective computing has matured over it...","Title: Towards a Deeper Modeling of Emotions: The Deep Method and its Application on Shame\nYear: 2021\n\nAbstract: Understanding emotions is key to Affective Computing. Emotion recognition focuses on the communicative component of emotions encoded in social signals. This view alone is insufficient for deeper understanding and computational representation of the internal, subjectively experienced component of emotions. This paper presents the Deep method as a starting point for a deeper computational modeling o...","Title: Implementing Parallel and Independent Movements for a Social Robot's Affective Expressions\nYear: 2021\n\nAbstract: The design and playback of natural and believable movements is a challenge for social robots. They have several limitations due to their physical embodiment, and sometimes also with regard to their software. Taking the example of the expression of happiness, we present an approach for implementing parallel and independent movements for a social robot, which does not have a full-fledged animation A...","Title: VoiceMe: Personalized voice generation in TTS\nYear: 2022\n\nAbstract: Novel text-to-speech systems can generate entirely new voices that were not seen during training. However, it remains a difficult task to efficiently create personalized voices from a high-dimensional speaker space. In this work, we use speaker embeddings from a state-of-the-art speaker verification model (SpeakerNet) trained on thousands of speakers to condition a TTS model. We employ a human sampling paradigm to explore this speaker latent space. We show that users can create voices that fit well to photos of faces, art portraits, and cartoons. We recruit online participants to collectively manipulate the voice of a speaking face. We show that (1) a separate group of human raters confirms that the created voices match the faces, (2) speaker gender apparent from the face is well-recovered in the voice, and (3) people are consistently moving towards the real voice prototype for the given face. Our results demonstrate that this technology can be applied in a wide number of applications including character voice development in audiobooks and games, personalized speech assistants, and individual voices for people with speech impairment.","Title: GANterfactual - Counterfactual Explanations for Medical Non-experts Using Generative Adversarial Learning.\nYear: 2022\n\nAbstract: With the ongoing rise of machine learning, the need for methods for explaining decisions made by artificial intelligence systems is becoming a more and more important topic. Especially for image classification tasks, many state-of-the-art tools to explain such classifiers rely on visual highlighting of important areas of the input data. Contrary, counterfactual explanation systems try to enable a counterfactual reasoning by modifying the input image in a way such that the classifier would have made a different prediction. By doing so, the users of counterfactual explanation systems are equipped with a completely different kind of explanatory information. However, methods for generating realistic counterfactual explanations for image classifiers are still rare. Especially in medical contexts, where relevant information often consists of textural and structural information, high-quality counterfactual images have the potential to give meaningful insights into decision processes. In this work, we present , an approach to generate such counterfactual image explanations based on adversarial image-to-image translation techniques. Additionally, we conduct a user study to evaluate our approach in an exemplary medical use case. Our results show that, in the chosen medical use-case, counterfactual explanations lead to significantly better results regarding mental models, explanation satisfaction, trust, emotions, and self-efficacy than two state-of-the art systems that work with saliency maps, namely LIME and LRP.","Title: Local and Global Explanations of Agent Behavior: Integrating Strategy Summaries with Saliency Maps (Extended Abstract).\nYear: 2022\n\nAbstract: With advances in reinforcement learning (RL), agents are now being developed in high-stakes application domains such as healthcare and transportation. Explaining the behavior of these agents is challenging, as they act in large state spaces, and their decision-making can be affected by delayed rewards. In this paper, we explore a combination of explanations that attempt to convey the global behavior of the agent and local explanations which provide information regarding the agent's decision-making in a particular state. Specifically, we augment strategy summaries that demonstrate the agent's actions in a range of states with saliency maps highlighting the information it attends to. Our user study shows that intelligently choosing what states to include in the summary (global information) results in an improved analysis of the agents. We find mixed results with respect to augmenting summaries with saliency maps (local information).","Title: MultiMediate'22: Backchannel Detection and Agreement Estimation in Group Interactions\nYear: 2022\n\nAbstract: ABSTRACTBackchannels, i.e. short interjections of the listener, serve important meta-conversational purposes like signifying attention or indicating agreement. Despite their key role, automatic analysis of backchannels in group interactions has been largely neglected so far. The MultiMediate challenge addresses, for the first time, the tasks of backchannel detection and agreement estimation from backchannels in group conversations. This paper describes the MultiMediate challenge and presents a novel set of annotations consisting of 7234 backchannel instances for the MPIIGroup Interaction dataset. Each backchannel was additionally annotated with the extent by which it expresses agreement towards the current speaker. In addition to a an analysis of the collected annotations, we present baseline results for both challenge tasks."],"string":"[\n \"Title: Tool-Supported User-Centred Prototyping of Mobile Applications\\nYear: 2011\\n\\nAbstract: There is evidence that user-centred development increases the user-friendliness of resulting products and thus the distinguishing features compared to products of competitors. However, the user-centred development requires comprehensive software and usability engineering skills to keep the process both cost-effective and time-effective. This paper covers that problem and provides insights in so-called user-centred prototyping UCP tools which support the production of prototypes as well as their evaluation with end-users. In particular, UCP tool called MoPeDT Pervasive Interface Development Toolkit for Mobile Phones is introduced. It provides assistance to interface developers of applications where mobile phones are used as interaction devices to a user's everyday pervasive environment. Based on found tool features for UCP tools, a feature study is described between related tools and MoPeDT as well as a comparative user study between this tool and a traditional approach. A further focus of the paper is the tool-supported execution of empiric evaluations.\",\n \"Title: Exploration of user reactions to different dialog-based interaction styles\\nYear: 2011\\n\\nAbstract: How human users perceive and interact with interactive story-telling applications has not been widely researched so far. In this paper, we present an experimental approach in which we investigate the impact of different dialog-based interaction styles on human users. To this end, an interactive demonstrator has been evaluated in two different versions: one providing a continuous interaction style where interaction is possible at any time, and another providing system-initiated interaction where the user can only interact at certain prompts.\",\n \"Title: From Physiological Signals To Emotions: Implementing And Comparing Selected Methods For Feature Extraction And Classification\\nYear: 2005\\n\\nAbstract: Little attention has been paid so far to physiological signals for emotion recognition compared to audio-visual emotion channels, such as facial expressions or speech. In this paper, we discuss the most important stages of a fully implemented emotion recognition system including data analysis and classification. For collecting physiological signals in different affective states, We used a music induction method which elicits natural emotional reactions from the subject.. Four-channel biosensors are used to obtain electromyogram, electrocardiogram, skin conductivity and respiration changes. After calculating a sufficient amount of features from the raw signals, several feature selection/reduction methods are tested to extract a new feature set consisting of the most significant features for improving classification performance. Three well-known classifiers, linear discriminant function, k-nearest neighbour and multilayer perceptron, are then used to perform supervised classification.\",\n \"Title: Trustworthy organic computing systems: challenges and perspectives\\nYear: 2010\\n\\nAbstract: Organic Computing (OC) systems differ from classical software systems as the topology and the participating components of the system are not predefined and therefore are subject to unforeseeable change during the systems' runtime. Thus, completely new challenges to the verification and validation of such systems as well as for interactions between system components and, of course, between the system and the user arise. These challenges can be subsumed by the terms trustworthiness or trust. This paper proposes - after exploring the notions and principles of trust in the literature - a definition of trust which encompasses all aspects that define the trustworthiness of an Organic Computing system. It then outlines the different research challenges that have to be tackled in order to provide an understanding of trust in OC-systems and gives perspectives on how this endeavour can be taken on. Current research initiatives in the area of trust in computing systems are reviewed and discussed.\",\n \"Title: A data-driven approach to model culture-specific communication management styles for virtual agents\\nYear: 2010\\n\\nAbstract: Virtual agents are a great opportunity in teaching inter-cultural competencies. Advantages, such as the repeatability of training sessions, emotional distance to virtual characters, the opportunity to over-exaggerate or generalize behavior or simply to save the costs for human training-partners support that idea. Especially the way communication is coordinated varies across cultures. In this paper, we present our approach of simulating differences in the management of communication for the American and Arabic cultures. Therefore, we give an overview of behavioral tendencies described in the literature, pointing out differences between the two cultures. Grounding our expectations in empirical data we analyzed a multi-modal corpora. These findings were integrated into a demonstrator using virtual agents and evaluated in a preliminary study.\",\n \"Title: From adaptive hypertext to personalized web companions\\nYear: 2002\\n\\nAbstract: The advent of Web browsers able to execute programs embedded in Web pages has enabled the use of embodied conversational characters on the Internet. In fact, an increasing number of Web sites employ animated characters for a large variety of tasks: virtual teachers guide users through online learning activities [6], Web chauffeurs provide recommendations on which links to follow, and virtual insurance agents help users to fill in forms. Web-based sales agents do not just present the customer with various products, but try to make the visit to an online store a unique experience; see [5] for an overview. Companies, such as Artificial Life, Extempo, Haptek, and Virtual Personalities,(1) create virtual characters specifically for the Internet.\",\n \"Title: Multimodal interaction with a virtual character in interactive storytelling\\nYear: 2010\\n\\nAbstract: A number of interactive storytelling (IS) systems offer the user the possibility to input natural language input which determines how a story progresses. We introduce a framework for real-time signal processing (SSI) to analyze the users' state which then can influence the feelings of the story characters and their actions in the story. SSI is not only used to enable more natural character responses that are sensitive to the user's state at runtime. In addition SSI offers the possibility to collect a large variety of synchronized user data which can be used to analyze the user's experience in offline mode. The underlying narrative in which the approach was tested is based on a classical XIXth century psychological novel: Madame Bovary, by Flaubert.\",\n \"Title: Level of detail AI for virtual characters in games and simulation\\nYear: 2010\\n\\nAbstract: Following recent research that takes the idea of Level of Detail (LOD) from its traditional use in 3D graphics and applies it to the artificial intelligence (AI) of virtual characters, we propose our approach on such an LOD AI. We describe how our approach handles LOD classification and how we used it to simplify the simulation quality of multiple aspects of the characters' behavior in an existing application. Finally, we delineate how we evaluated our approach with both a performance and perception analysis and report our findings.\",\n \"Title: The TARDIS Framework: Intelligent Virtual Agents for Social Coaching in Job Interviews\\nYear: 2013\\n\\nAbstract: The TARDIS project aims to build a scenario-based serious-game simulation platform for NEETs and job-inclusion associations that supports social training and coaching in the context of job interviews. This paper presents the general architecture of the TARDIS job interview simulator, and the serious game paradigm that we are developing.\",\n \"Title: Building smart embodied virtual characters\\nYear: 2003\\n\\nAbstract: Embodied conversational characters are autonomous, graphically embodied virtual creatures that live in a 2D or 3D virtual environment. They are able to interact intelligently with human users, other characters, and their digital environment. While for decades research has concentrated on geometric body modelling and the development of animation and rendering techniques for virtual characters, other qualities have now come in focus as well, including the provision of conversational skills as well as the simulation of believable behavior including affect and peculiarities induced by individual personality traits. As a consequence, the domain of virtual characters has become much more diverse and now encompasses a wide range of disciplines, from computer graphics and animation to AI and more recently also psychology, sociology as well as design and arts. The current paper discusses a number of design issues that arise when building an application with one or more embodied characters. By means of selected sample applications we also illustrate a yet ongoing development of animated presentation agents starting with TV-style information presenters to highly interactive multi-character scenarios in which information is conveyed to the user in the form of multi-party conversations.\",\n \"Title: Some Pitfalls for Developing Enculturated Conversational Agents\\nYear: 2009\\n\\nAbstract: A review of current agent-based systems exemplifies that a Western perspective is predominant in the field. But as conversational agents focus on rich multimodal interactive behaviors that underlie face-to-face encounters, it is indispensable to incorporate cultural heuristics of such behaviors into the system. In this paper we examine some of the pitfalls that arise in developing such systems.\",\n \"Title: MoPeDT: features and evaluation of a user-centred prototyping tool\\nYear: 2010\\n\\nAbstract: User-Centred Prototyping (UCP) tools are expected to support interface developers in order to more efficiently, effectively and satisfactorily design, evaluate and analyse user-friendly products by an all-in-one tool solution. We developed such a UCP tool called MoPeDT that supports the user-centred development of interactive evolutionary prototypes for mobile phones in the context of the Internet of Things. In this paper we address our tool features for the design, evaluation and analysis phase that mostly base on meaningful features from related tools. Additionally, we cover potential enhancements to former UCP tools in order to support interface developers with a wide-ranging playground to investigate the user's behaviour and preferences. The paper also describes MoPeDT's evaluation with 20 students over one month that investigated the interface developer's efficiency, effectiveness and satisfaction when applying our UCP tool. As an outcome of this study we describe potential benefits and problems that might be of interest to other developers of UCP tools.\",\n \"Title: Trust-based decision-making for the adaptation of public displays in changing social contexts.\\nYear: 2013\\n\\nAbstract: Public displays may adapt intelligently to the social context, tailoring information on the screen, for example, to the profiles of spectators, their gender or based on their mutual proximity. However, such adaptation decisions should on the one hand match user preferences and on the other maintain the user's trust in the system. A wrong decision can negatively influence the user's acceptance of a system, cause frustration and, as a result, make users abandon the system. In this paper, we propose a trust-based mechanism for automatic decision-making, which is based on Bayesian Networks. We present the process of network construction, initialization with empirical data, and validation. The validation demonstrates that the mechanism generates accurate decisions on adaptation which match user preferences and support user trust.\",\n \"Title: A plug-and-play framework for theories of social group dynamics\\nYear: 2006\\n\\nAbstract: We present an extensible framework for behavior control of social agents in a multi-agent system that has the following features. It implements a basic repertoire of socio-psychological models of behavior and interpersonal interactions that can be plugged and unplugged at will depending on the specific context of the application. This enables us to test several theories in isolation or combination to increase the transparency of the system and to investigate how the inclusion of a certain theory influences the behavior of the agents. Unlike earlier approaches, our approach is not bound to a specific theory. Thus, it becomes possible to run a simulation with the same set of agents using different theories to compare their effect.\",\n \"Title: Generating coherent presentations employing textual and visual material\\nYear: 1995\\n\\nAbstract: The objective of the work described in this paper is the development of an intelligent generation system which is able to combine textual and visual material. As coherent presentations cannot be generated by simply merging verbalization and visualization results into multimedia output, the processes for content determination, medium selection and content realization in different media have to be carefully coordinated. We first show that multimedia presentations and pure text follow similar structuring principles. Based on this insight, we sketch how techniques for planning text and discourse can be generalized to allow the structure and contents of multimedia communications to be planned as well. In particular, we explain how our approach handles the crucial task of process coordination.\",\n \"Title: Studies on grounding with gaze and pointing gestures in human-robot-interaction\\nYear: 2012\\n\\nAbstract: In this study we investigated the use of gaze and pointing gestures in scenarios where a human has to follow the instructions of a humanoid robot. Our objective was to analyze the performance of a human participant, that solves an abstract jigsaw puzzle with the help of our robot instructor, in different grounding scenarios with varying difficulty. Furthermore we investigated how the attitude towards the robot and the self-assessment of the participant changed. Our results support that adding gaze to the interaction usually improves the interaction, but often additional pointing gestures are needed to make a significant difference.\",\n \"Title: Trust-centered design for multi-display applications\\nYear: 2010\\n\\nAbstract: This work describes a trust-centered user study that was conducted during the design process of a multi-display ubiquitous application. The objective of the study was to find out how the adaptation of the displays should be designed in order to protect user trust. The study was conducted in the form of focus group interviews; it investigated user attitude towards data and events that can be seen as trust-critical in a multi-display interaction scenario. The quantitative results, along with user comments and discussions, provide an interesting insight how the system should be adapted in order to preserve user trust.\",\n \"Title: An immersive game – augsburg cityrun\\nYear: 2006\\n\\nAbstract: We present a platform for creating immersive 3D games including a new interface for navigating through virtual scenes. One innovative part of this application is a crowd simulation with an emergent behaviour of virtual characters. While the users has to move very quickly through a crowd of nearly two hundred virtual characters he is supported by a precise, fast operating, and unobtrusive navigation interface.\",\n \"Title: Simplified facial animation control utilizing novel input devices: a comparative study\\nYear: 2009\\n\\nAbstract: Editing facial expressions of virtual characters is quite a complex task. The face is made up of many muscles, which are partly activated concurrently. Virtual faces with human expressiveness are usually designed with a limited amount of facial regulators. Such regulators are derived from the facial muscle parts that are concurrently activated. Common tools for editing such facial expressions use slider-based interfaces where only a single input at a time is possible. Novel input devices, such as gamepads or data gloves, which allow parallel editing, could not only speed up editing, but also simplify the composition of new facial expressions. We created a virtual face with 23 facial controls and connected it with a slider-based GUI, a gamepad, and a data glove. We first conducted a survey with professional graphics designers to find out how the latter two new input devices would be received in a commercial context. A second comparative study with 17 subjects was conducted to analyze the performance and quality of these two new input devices using subjective and objective measurements.\",\n \"Title: Integrating models of personality and emotions into lifelike characters\\nYear: 1999\\n\\nAbstract: Abstract. A growing ,number ,of research ,projects in academia ,and industry have recently started to develop ,lifelike agents as a ,new ,metaphor ,for highly personalised human-machine ,communication. ,A strong argument ,in favour ,of using such characters in the ,interface is the ,fact that they make ,humancomputer,interaction more ,enjoyable ,and ,allow for communication ,styles common,in human-human ,dialogue. Our earlier work ,in this ,area has concentrated on the development of animated presenters that show, explain, and verbally comment ,textual and graphical output on a ,window-based ,interface. Even though first empirical studies have been very encouraging,and revealed a strong affective impact of our Personas [23], they also suggest that simply embodying an interface agent is insufficient. To come across as believable, an agent needs to incorporate a deeper model of personality and emotions, and in particular directly connect these two concepts.\",\n \"Title: Intellimedia: making multimedia usable by exploiting AI methods\\nYear: 1995\\n\\nAbstract: This paper sketches how we integrated multiple AI methods, such as planning, constraintprocessing, temporal reasoning, natural processing processing and knowledge representation,into the presentations systems WIP and PPP.\",\n \"Title: Composing Affective Music with a Generate and Sense Approach\\nYear: 2004\\n\\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user- specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.\",\n \"Title: Smart Sensor Integration: A Framework for Multimodal Emotion Recognition in Real-Time\\nYear: 2009\\n\\nAbstract: Affect sensing by machines has been argued as an es- sential part of next-generation human-computer interaction (HCI). To this end, in the recent years a large number of studies have been conducted, which report automatic recog- nition of emotion as a difficult, but feasible task. However, most effort has been put towards offline analysis, whereas to date only few applications exist, which are able to react to a user's emotion in real-time. In response to this deficit we introduce a framework we call Smart Sensor Integra- tion (SSI), which considerably jump-starts the development of multimodal online emotion recognition (OER) systems. In particular SSI supports the pattern recognition pipeline by offering tailored tools for data segmentation, feature ex- traction, and pattern recognition, as well as, tools to apply them offline (training phase) and online (real-time recog- nition). Furthermore, it has been designed to handle input from various input modalities and to suit the fusion of mul- timodal information.\",\n \"Title: Augmented reality using a 3D motion capturing suit\\nYear: 2013\\n\\nAbstract: In the paper, we propose an approach that immerses the human user in an Augmented Reality (AR) environment with the use of an inertial motion capturing suit and a Head Mounted Displays system. The proposed approach allows for full body interaction with the AR environment in real-time and it does not require the use of any markers or cameras.\",\n \"Title: A sensing architecture for empathetic data systems\\nYear: 2013\\n\\nAbstract: Today's increasingly large and complex databases require novel and machine aided ways of exploring data. To optimize the selection and presentation of data, we suggest an unconventional approach. Instead of exclusively relying on explicit user input to specify relevant information or to navigate through a data space, we exploit the power and potential of the users' unconscious processes in addition. To this end, the user is immersed in a mixed reality environment while his bodily reactions are captured using unobtrusive wearable devices. The users' reactions are analyzed in real-time and mapped onto higher-level psychological states, such as surprise or boredom, in order to trigger appropriate system responses that direct the users' attention to areas of potential interest in the visualizations. The realization of such a close experience-based human-machine loop raises a number of technical challenges, such as the real-time interpretation of psychological user states. The paper at hand describes a sensing architecture for empathetic data systems that has been developed as part of such a loop and how it tackles the diverse challenges.\",\n \"Title: A Systematic Comparison of Different HMM Designs for Emotion Recognition from Acted and Spontaneous Speech\\nYear: 2007\\n\\nAbstract: In this work we elaborate the use of hidden Markov models (HMMs) for speech emotion recognition as a dynamic alternative to static modelling approaches. Since previous work on this field does not yet define a clear line which HMM design should be prioritised for this task, we run a systematic analysis of different HMM configurations. Furthermore, experiments are carried out on an acted and a spontaneous emotions corpus, since little is known about the suitability of HMMs for spontaneous speech. Additionally, we consider two different segmentation levels, namely words and utterances. Results are compared with the outcome of a support vector machine classifier trained on global statistics features. While for both databases similar performance was observed on utterance level, the HMM-based approach outperformed static classification on word level. However, setting up general guidelines which kind of models are best suited appeared to be rather difficult.\",\n \"Title: Combining Alternatives in the Multimedia presentation of Decision Support Information for Real-Time Control\\nYear: 1998\\n\\nAbstract: Multimedia technology is emerging as a key element in the area of Decision Sup- port Systems (DSS) since well-designed multimedia presentations help the human decision maker to assimilate relevant information more easily. The use of multiple media, however, increases the complexity of the presentation design task. Especially when complex information structures have to be presented under time pressuread hoc' solutions to presentation generation are getting more and more impractical, if not impossible to use. In this paper we report on our approach to enhance a DSS for real-time traffic management with an advanced component for the automated gener- ation of multimedia presentations. A common problem in this application class is the presentation of alternatives such as different explanations or predictions for a current traffic situation, or different sequences of control actions which may be initiated to resolve a problem. We describe a novel approach to provide aggregated information presentations rather than presenting alternatives just one after the other.\",\n \"Title: Generating culture-specific gestures for virtual agent dialogs\\nYear: 2010\\n\\nAbstract: Integrating culture into the behavioral model of virtual agents has come into focus lately. When investigating verbal aspects of behavior, nonverbal behaviors are desirably added automatically, driven by the speech-act. In this paper, we present a corpus driven approach of generating gestures in a culture-specific way that accompany agent dialogs. The frequency of gestures and gesture-types, the correlation of gesture-types and speech-acts as well as the expressivity of gestures have been analyzed in the two cultures of Germany and Japan and integrated into a demonstrator.\",\n \"Title: Creating and Scripting Second Life Bots Using MPML3D\\nYear: 2008\\n\\nAbstract: The use of virtual characters becomes invariably common in computer games and other applications. So-called \\\"bots\\\" (computer-controlled virtual characters), may explain virtual settings in a natural way. We describe an example scenario in the online world Second Life [1] in order to explain to content creators how to create bots and script their behavior using the well established authoring language MPML3D [2]. MPML3D does not assume knowledge of a high-level programming language. In Second Life users are represented by their avatars (virtual characters controlled by humans) and its environment provides character models, animations and a graphics engine.\",\n \"Title: From annotated multimodal corpora to simulated human-like behaviors\\nYear: 2006\\n\\nAbstract: Multimodal corpora prove useful at different stages of the development process of embodied conversational agents. Insights into human-human communicative behaviors can be drawn from such corpora. Rules for planning and generating such behavior in agents can be derived from this information. And even the evaluation of human-agent interactions can rely on corpus data from human-human communication. In this paper, we exemplify how corpora can be exploited at the different development steps, starting with the question of how corpora are annotated and on what level of granularity. The corpus data can be used either directly for imitating the human behavior recorded in the corpus or rules can be derived from the data which govern the behavior planning process. Corpora can even play a vital role in the evaluation of agent systems. Several studies are presented that make use of corpora for the evaluation task.\",\n \"Title: WIP and PPP: a comparison of two multimedia presentation systems in terms of the standard reference model\\nYear: 1997\\n\\nAbstract: In this paper, the Standard Reference Model for IMMPS is used for analysing the architectural design of two multimedia presentation systems which have been built at DFKI over the past 10 years. We first present the systems as described by the authors and then compare them in terms of the reference model. (C) 1997 Elsevier Science B.V.\",\n \"Title: Adding Life-Like Synthetic Characters to the Web\\nYear: 2000\\n\\nAbstract: With the advent of web browsers that are able to execute programs embedded in web pages, the use of animated characters for\\n the presentation of information over the web has become possible. A strong argument in favour of using such characters in\\n a web interface is the fact that they make human-computer interaction more enjoyable and allow for the emulation of communication\\n styles common in human-human dialogue. In this paper we discuss three ongoing DFKI projects on life-like synthetic characters\\n in the internet. While all agents rely on the same approach for automated script generation, we use different player technologies\\n which will be discussed in the light of different applications.\",\n \"Title: Endowing Spoken Language Dialogue Systems with Emotional Intelligence\\nYear: 2004\\n\\nAbstract: While most dialogue systems restrict themselves to the adjustment of the propositional contents, Pur work concentrates on the generation of stylistic variations in order to improve the user's perception of the interaction. To accomplish this goal, our approach integrates a social theory of politeness with a cognitive theory of, emotions. We propose a hierarchical selection process for politeness behaviors in order to enable the refinement of decisions in case additional context information becomes available.\",\n \"Title: Role assignment via physical mobile interaction techniques in mobile multi-user applications for children\\nYear: 2007\\n\\nAbstract: The development of engaging user interfaces that support collaboration is a great challenge - in particular if users are children. We consider mobile phones as appropriate devices for multi-user interactions with a system because novel forms of physical mobile interaction techniques with smart objects yield lots of benefits, such as being intuitive and playful to use, but also addressing children's needs for curiosity. In this paper, we introduce our approach to multi-user game-like scenarios within an ambient intelligence context which are controlled via different mobile phones and their supported interaction techniques. By providing children with multiple mobile phones we structure interactions in multi-user settings and prevent undesirable situations, such as dominant users or off-topic actions. Children get access to various physical mobile interaction techniques for interactions with smart objects which are all required to fulfill one common goal. In this way, social interaction arises in a natural manner. In order to motivate and evaluate our approach, we developed two ambient intelligence applications called The World Explorer and The Escape. Results of a user study showed that children liked working in a group and that physical mobile interaction techniques are a promising approach to increase engagement and foster social interactions but also to prevent chaotic situations by balancing the distribution of activities in multi-user settings.\",\n \"Title: Workshop: eye gaze in intelligent human machine interaction\\nYear: 2010\\n\\nAbstract: This workshop brought researchers from academia and industry together to share recent advances and discuss research directions and opportunities for next generation of intelligent human machine interaction that incorporate eye gaze.\",\n \"Title: To see and to be seen in the virtual beer garden: a gaze behavior system for intelligent virtual agents in a 3D environment\\nYear: 2009\\n\\nAbstract: Aiming to increase the believability of intelligent virtual agents, this paper describes the implementation of a parameterizable gaze behavior system based on psychological notions of human gaze. The resulting gaze patterns and agent behaviors cover a wide range of possible uses due to this parametrization. We also show how we integrated and used the system within a virtual environment.\",\n \"Title: Interpreting social cues to generate credible affective reactions of virtual job interviewers.\\nYear: 2014\\n\\nAbstract: In this paper we describe a mechanism of generating credible affective reactions in a virtual recruiter during an interaction with a user. This is done using communicative performance computation based on the behaviours of the user as detected by a recognition module. The proposed software pipeline is part of the TARDIS system which aims to aid young job seekers in acquiring job interview related social skills. In this context, our system enables the virtual recruiter to realistically adapt and react to the user in real-time.\",\n \"Title: Introduction to the special issue on eye gaze in intelligent human-machine interaction\\nYear: 2012\\n\\nAbstract: Given the recent advances in eye tracking technology and the availability of nonintrusive and high-performance eye tracking devices, there has never been a better time to explore new opportunities to incorporate eye gaze in intelligent and natural human-machine communication. In this special issue, we present six articles that cover various aspects of eye gaze in human-machine interaction, including applications of gaze tracking in human-machine interaction, techniques that recognize gaze gestures and render gaze behaviors, and the analysis of gaze behaviors in social interactions.\",\n \"Title: Increasing learners' motivation through pedagogical agents: the cast of virtual characters in the dynalearn ILE\\nYear: 2011\\n\\nAbstract: Motivation is a critical requirement for successful learning. Previous research has identified that animated pedagogical agents can increase motivation. Following these results, we present the cast of pedagogical agents in the DynaLearn Intelligent Learning Environment. Each of these agents is associated with one of the different support types available in the environment, giving each agent a clearly defined role. We describe the different character roles, how their knowledge is generated and related to the pedagogical purpose at hand, how they interact with the learners and finally how this interaction helps increasing the learners' motivation. To assess this, we conducted a preliminary evaluation with three of the characters and report our findings.\",\n \"Title: Avatar culture: cross-cultural evaluations of avatar facial expressions\\nYear: 2009\\n\\nAbstract: Avatars are increasingly used to express our emotions in our online communications. Such avatars are used based on the assumption that avatar expressions are interpreted universally among all cultures. This paper investigated cross-cultural evaluations of avatar expressions designed by Japanese and Western designers. The goals of the study were: (1) to investigate cultural differences in avatar expression evaluation and apply findings from psychological studies of human facial expression recognition, (2) to identify expressions and design features that cause cultural differences in avatar facial expression interpretation. The results of our study confirmed that (1) there are cultural differences in interpreting avatars’ facial expressions, and the psychological theory that suggests physical proximity affects facial expression recognition accuracy is also applicable to avatar facial expressions, (2) positive expressions have wider cultural variance in interpretation than negative ones, (3) use of gestures and gesture marks may sometimes cause counter-effects in recognizing avatar facial expressions.\",\n \"Title: Using the mobile application EDDY for gathering user information in the requirement analysis\\nYear: 2010\\n\\nAbstract: The users' knowledge and requirements are important factors in the design of products. To ensure the success of products designers and developers have to get to know their target group users better. Over the years a lot of innovative user centered design studies have been written. Many researchers believe that these studies could be used by developers to help them in the process of creating new products. This paper presents a framework called EDDY that aims at facilitating the development of mobile applications for gathering various kinds of data. Such a framework and applications based on it should be helpful for the data collection during studies such as Cultural Probes and the Experience Sampling Method. These approaches involve the users as the persons who collect the required information themselves. In this paper we evaluate the advantages of EDDY for such studies. We investigated whether there is a significant advantage in using a mobile application for the documentation of a user's everyday life instead of using a classical kit.\",\n \"Title: Knowledge-Based Generation of Illustrated Documents\\nYear: 1991\\n\\nAbstract: The task of the knowledge-based presentation system WIP is the generation of a variety of multimodal documents from an input consisting of a formal description of the communicative intent of a planned presentation. WIP generates illustrated texts that are customized for the intended audience and situation. We present the architecture of WIP and introduce as its major components the presentation planner, the layout manager, the text generator and the graphics generator. An extended notion of coherence for multimodal documents is introduced that can be used to constrain the presentation planning process. The paper focuses on the coordination of contents planning and layout that is necessary to produce a coherent illustrated text. In particular, we discuss layout revisions after contents planning and the influence of layout constraints on text generation. We show that in WIP the design of a multimodal document is viewed as a non-monotonic planning process that includes various revisions of preliminary results in order to achieve a coherent output with an optimal media mix.\",\n \"Title: Bossy or wimpy: expressing social dominance by combining gaze and linguistic behaviors\\nYear: 2010\\n\\nAbstract: This paper examines the interaction of verbal and nonverbal information for conveying social dominance in intelligent virtual agents (IVAs). We expect expressing social dominance to be useful in applications related to persuasion and motivation; here we simply test whether we can affect users' perceptions of social dominance using procedurally generated conversational behavior. Our results replicate previous results showing that gaze behaviors affect dominance perceptions, as well as providing new results showing that, in our experiments, the linguistic expression of disagreeableness has a significant effect on dominance perceptions, but that extraversion does not.\",\n \"Title: Integrating information from speech and physiological signals to achieve emotional sensitivity\\nYear: 2005\\n\\nAbstract: Recently, there has been a significant amount of work on the recognition of emotions from speech and biosignals. Most approaches toemotion recognition so farconcentrate on asingle modality and do not take advantage of the fact that an integrated multimodal analysis may help to resolve ambiguities and com- pensate for errors. In this paper, we describe various methods for fusing physiological and voice data at the feature-level and the decision-level as well as a hybrid integration scheme. The resultsof the integrated recognition approach arethen compared with the individual recognition results from each modality.\",\n \"Title: Exploring The Benefits Of Discretization Of Acoustic Features For Speech Emotion Recognition\\nYear: 2009\\n\\nAbstract: We present a contribution to the Open Performance sub-challenge of the INTERSPEECH 2009 Emotion Challenge. We evaluate the feature extraction and classifier of EmoVoice, our framework for real-time emotion recognition from voice on the challenge database and achieve competitive results. Furthermore, we explore the benefits of discretizing numeric acoustic features and find it beneficial in a multi-class task.\",\n \"Title: From Simulated Dialogues to Interactive Performances\\nYear: 2001\\n\\nAbstract: In this contribution, we argue in favor of a shift from applications with single presentation agents towards flexible performances given by a team of characters as a new presentation style. We will illustrate our approach by means of two subsequent versions of a test-bed called the \\\"Inhabited Market Place\\\" (IMP1 and IMP2). In IMP1, the attribute \\\"flexible\\\" refers to the system's ability to adapt a presentation to the needs and preferences of a particular user. In IMP2, flexibility additionally refers to the user's option of actively participating in a computer-based performance and influencing the behavior of the involved characters at runtime. While a plan-based approach has proven appropriate in both versions to automatically control the behavior of the agents, IMP2 calls for highly reactive and distributed behavior planning.\",\n \"Title: Visual communication in interactive multimedia\\nYear: 2011\\n\\nAbstract: Careful selection of graphical design can push the narrative strength of graphical projects by adjusting the visual statements to the content-wise statements. While many projects of computer science lack of consequent implementation of artistic principles, graphic designers tend to neglect user interaction and evaluation. In a recent project we therefore started a successful approach to combine both sides. In future work we plan to research on further integration of visual narration into interactive storytelling.\",\n \"Title: Four-Channel Biosignal Analysis and Feature Extraction for Automatic Emotion Recognition\\nYear: 2008\\n\\nAbstract: This paper investigates the potential of physiological signals as a reliable channel for automatic recognition of user's emotial state. For the emotion recognition, little attention has been paid so far to physiological signals compared to audio-visual emotion channels such as facial expression or speech. All essential stages of automatic recognition system using biosignals are discussed, from recording physiological dataset up to feature-based multiclass classification. Four-channel biosensors are used to measure electromyogram, electrocardiogram, skin conductivity and respiration changes. A wide range of physiological features from various analysis domains, including time/frequency, entropy, geometric analysis, subband spectra, multiscale entropy, etc., is proposed in order to search the best emotion-relevant features and to correlate them with emotional states. The best features extracted are specified in detail and their effectiveness is proven by emotion recognition results.\",\n \"Title: Werewolves, cheats, and cultural sensitivity\\nYear: 2014\\n\\nAbstract: MIXER (Moderating Interactions for Cross-Cultural Empathic Relationships), which applies a novel approach to the education of children in cultural sensitivity. MIXER incorporates intelligent affective and interactive characters, including a model of a Theory of Mind mechanism, in a simulated virtual world. We discuss the relevant pedagogical approaches, related work, the underlying mind model used for MIXER agents as well as its innovative interaction interface utilising a tablet computer and a pictorial interaction language. We then consider the evaluation of the system, whether this shows it met its pedagogical objectives, and what can be learned from our results.\",\n \"Title: A flexible platform for building applications with life-like characters\\nYear: 2003\\n\\nAbstract: During the last years, an increasing number of R&D projects has started to deploy life-like characters for presentation tasks in a diverse range of application areas, including, for example, E-Commerce, E-learning, and help systems. Depending on factors, such as the degree of interactivity and the number of the deployed characters, different architectures have been proposed for system implementation. In this contribution, we first analyse a number of existing user interfaces with presentation characters from an architectural point of view. We then introduce the MIAU platform and illustrate by means of illustrated generation examples how MIAU can be used for the realization of character applications with different conversational settings. Finally, we sketch a number of potential application fields for the MIAU platform\",\n \"Title: Comparing Feature Sets For Acted And Spontaneous Speech In View Of Automatic Emotion Recognition\\nYear: 2005\\n\\nAbstract: We present a data-mining experiment on feature selection for automatic emotion recognition. Starting from more than 1000 features derived from pitch, energy and MFCC time series, the most relevant features in respect to the data are selected from this set by removing correlated features. The features selected for acted and realistic emotions are analysed and show significant differences. All features are computed automatically and we also contrast automatically with manually units of analysis. A higher degree of automation did not prove to be a disadvantage in terms of recognition accuracy.\",\n \"Title: Modeling multimodal integration with event logic charts\\nYear: 2012\\n\\nAbstract: In this paper we present a novel approach to the combined modeling of multimodal fusion and interaction management. The approach is based on a declarative multimodal event logic that allows the integration of inputs distributed over multiple modalities in accordance to spatial, temporal and semantic constraints. In conjunction with a visual state chart language, our approach supports the incremental parsing and fusion of inputs and a tight coupling with interaction management. The incremental and parallel parsing approach allows us to cope with concurrent continuous and discrete interactions and fusion on different levels of abstraction. The high-level visual and declarative modeling methods support rapid prototyping and iterative development of multimodal systems.\",\n \"Title: Integrating a Virtual Agent into the Real World: The Virtual Anatomy Assistant Ritchie\\nYear: 2007\\n\\nAbstract: Augmented realities, which are partially real and partially virtual, open up new ways for humans to interact with Embodied Conversational Agents (ECAs) since they allow users to meet ECAs in the physical space. Nevertheless, attempts to integrate ECAs as digital overlays in a physical space have been rare. Obvious reasons are the high demands such an integration puts to the animation of ECAs as virtual augmentations of the physical space, their capabilities to perceive not only the virtual, but also the physical world as well as reactive behavior control. In this paper, we describe our technical contributions towards solving these challenges. To illustrate our ideas, we present the virtual anatomy assistant Ritchie that monitors the user's actions in a physical space and dynamically responds to them.\",\n \"Title: Introducing Multiple Interaction Devices to Interactive Storytelling: Experiences from Practice\\nYear: 2009\\n\\nAbstract: Introducing multiple interaction devices into an interactive story provides certain advantages to the system: it fosters collaboration in multi-user settings, increases user involvement, and addresses more perception channels and user senses. It is a challenging task for designers to introduce multiple interaction devices into an interactive storytelling (IS) system. In this paper we report on our experiences with the design and evaluation of an IS system, called ORIENT. The system was created for multi-user settings; it embeds various interaction devices, such as mobile phones, a dance pad, a Wiimote, and RFID tags. We report on user feedback and derive design challenges that should be considered when creating interaction devices for IS systems.\",\n \"Title: EmoVoice -- A Framework for Online Recognition of Emotions from Voice\\nYear: 2008\\n\\nAbstract: We present EmoVoice, a framework for emotional speech corpus and classifier creation and for offline as well as real-time online speech emotion recognition. The framework is intended to be used by non-experts and therefore comes with an interface to create an own personal or application specific emotion recogniser. Furthermore, we describe some applications and prototypes that already use our framework to track online emotional user states from voice information.\",\n \"Title: Managing user trust for self-adaptive ubiquitous computing systems\\nYear: 2010\\n\\nAbstract: Ubiquitous computing systems can cause serious problems for user trust. In particular if the system is self-adaptive and situations appear which are poorly self-explanatory. In this paper we aim at the trust management of adaptive systems. We present a user study that covers the correlation of trust dimensions and user feelings on user trust. As results of this study, a Bayesian Network is introduced that, at the design time and runtime of the system, provides knowledge about the interplay between a truster's disposition, system events and actions, trust dimensions, user trust and user response.\",\n \"Title: Bi-channel sensor fusion for automatic sign language recognition\\nYear: 2008\\n\\nAbstract: In this paper, we investigate the mutual-complementary functionality of accelerometer (ACC) and electromyogram (EMG) for recognizing seven word-level sign vocabularies in German sign language (GSL). Results are discussed for the single channels and for feature-level fusion for the bichannel sensor data. For the subject-dependent condition, this fusion method proves to be effective. Most relevant features for all subjects are extracted and their universal effectiveness is proven with a high average accuracy for the single subjects. Additionally, results are given for the subject-independent condition, where subjective differences do not allow for high recognition rates. Finally we discuss a problem of feature-level fusion caused by high disparity between accuracies of each single channel classification.\",\n \"Title: The Smart Sensor Integration Framework and its Application in EU Projects\\nYear: 2010\\n\\nAbstract: Affect sensing by machines is an essential part of next-generation human-computer interaction (HCI). However, despite the large effort carried out in this field during the last decades, only few applications exist, which are able to react to a user's emotion in real-time. This is certainly due to the fact that emotion recognition is a challenging part in itself. Another reason is that so far most effort has been put towards offline analysis and only few applications exist, which can react to a user's emotion in real-time. In response to this deficit we have developed a framework called Smart Sensor Integration (SSI), which considerably jump-starts the development of multimodal online emotion recognition (OER) systems. In this paper, we introduce the SSI framework and describe how it is successfully applied in different projects under grant of the European Union, namely the CALLAS and METABO project, and the IRIS network.\",\n \"Title: Lets come together: social navigation behaviors of virtual and real humans\\nYear: 2005\\n\\nAbstract: In this paper, we present a game-like scenario that is based on a model of social group dynamics inspired by theories from the social sciences. The model is augmented by a model of proxemics that simulates the role of distance and spatial orientation in human-human communication. By means of proxemics, a group of human participants may signal other humans whether they welcome new group members to join or not. In this paper, we describe the results of an experiment we conducted to shed light on the question of how humans respond to such cues when shown by virtual humans.\",\n \"Title: Xenakis: combining tangible interaction with probability-based musical composition\\nYear: 2008\\n\\nAbstract: In this paper we present the table-based tangible interface application Xenakis which uses probability models in order to compose music in a way that can be strongly influenced by the user. Our musical sequencing application is based on a framework for tangible interfaces with an architecture that is strongly inspired by the model-view-controller pattern. In addition, we developed a hardware setup for tangible interfaces and used MatraX for tracking markers. The sequencer is the first implementation based on this framework. It allows users to create music simply by moving tangibles on the table. The graphics engine Horde3D is used to visualize the user-interaction and to show the relationships between the tangible objects on the table, creating an appealing audio-visual experience. An evaluation with 37 first time users was conducted in order to discover the strong and the weak points of such tangible user interfaces, especially in the context of our application.\",\n \"Title: Gamble v2.0: social interactions with multiple users\\nYear: 2005\\n\\nAbstract: Gamble is a test-bed for affective multiparty interactions which allows us to investigate social behavior of an agent towards users and vice versa. The CASA paradigm [9] claims that agents are regarded and treated as social actors. Whereas in 1:1 interactions it was shown that people tend to consider their \\\"traffic-rules\\\" of social interaction, we know little about scenarios in which more than one user is interacting with the same agent at the same time.\",\n \"Title: Culture-related topic selection in small talk conversations across Germany and Japan\\nYear: 2011\\n\\nAbstract: Small talk can be used in order to build a positive relationship towards a virtual character. However the choice of topics in a conversation can be dependent on social background. In this paper, we explore culture-related differences in small talk for the German and Japanese cultures. Based on findings from the literature and verified by a corpus analysis, we integrated prototypical German and Japanese small talk conversations into a multiagent system. In evaluation studies conducted in the two target cultures, we investigated whether participants prefer agent dialogs that were designed to reflect their own cultural background.\",\n \"Title: Coping with temporal constraints in multimedia presentation planning\\nYear: 1996\\n\\nAbstract: Computer-based presentation systems enable the realization of effective and dynamic presentation styles that incorporate multiple media. Obvious examples are animated user interface agents which verbally comment on multimedia objects displayed on the screen while performing cross-media and cross-window pointing gestures. The design of such presentations must account for the temporal coordination of media output and the agent's behavior. In this paper we describe a new presentation system which not only creates the multimedia objects to be presented, but also generates a script for presenting the material to the user. In our system, this script is forwarded to an animated presentation agent running the presentation. The paper details the kernel of the system which is a component for planning temporally coordinated multimedia.\",\n \"Title: Too close for comfort?: adapting to the user's cultural background\\nYear: 2007\\n\\nAbstract: The cultural context of the user is a largely neglected aspect of human centered computing. This is because culture is a very fuzzy concept and even with a computational model of culture it remains difficult to derive the necessary information to recognize the user's cultural background. Such information is only indirectly available and has to be derived from the observable multimodal behavior of the user. We propose the usage of a dimensional model of culture that allows applying computational methods to derive a user's cultural background and to adjust the system's behavior accordingly. To this end, a Bayesian network is applied to allow for the necessary inferences despite the fact that the given knowledge about the user's behavior is incomplete and unreliable.\",\n \"Title: Cultural behaviors of virtual agents in an augmented reality environment\\nYear: 2012\\n\\nAbstract: This paper presents a pilot evaluation study that investigates the physiological response of users when interacting with virtual agents that resemble cultural behaviors in an Augmented Reality environment. In particular, we analyze users from the Arab and German cultural backgrounds. The initial results of our analysis are promising and show that users tend to have a higher physiological arousal towards virtual agents that do not exhibit behaviors of their cultural background.\",\n \"Title: Adaptive art --- a shape language driven approach to communicate dramaturgy and mood\\nYear: 2011\\n\\nAbstract: Graphic designers and visual artists express their narrative intentions using visual tools which essentially include the styling of shapes. In classic art forms design decisions are limited to the initial creation process. Although technical progress makes it possible to adjust content-wise dramaturgy in real-time, the graphical design process often still has static characteristics. In our current work we therefore study how dramaturgical non-linearity can be combined with a flexible visual shape language to conform content-wise narration to visual expressiveness in real-time.\",\n \"Title: NovA: Automated Analysis of Nonverbal Signals in Social Interactions\\nYear: 2013\\n\\nAbstract: Previous studies have shown that the success of interpersonal interaction depends not only on the contents we communicate explicitly, but also on the social signals that are conveyed implicitly. In this paper, we present NovA (NOnVerbal behavior Analyzer), a system that analyzes and facilitates the interpretation of social signals conveyed by gestures, facial expressions and others automatically as a basis for computer-enhanced social coaching. NovA records data of human interactions, automatically detects relevant behavioral cues as a measurement for the quality of an interaction and creates descriptive statistics for the recorded data. This enables us to give a user online generated feedback on strengths and weaknesses concerning his social behavior, as well as elaborate tools for offline analysis and annotation.\",\n \"Title: AutoSelect: What You Want Is What You Get: Real-Time Processing of Visual Attention and Affect\\nYear: 2006\\n\\nAbstract: While objects of our focus of attention (“where we are looking at”) and accompanying affective responses to those objects is part of our daily experience, little research exists on investigating the relation between attention and positive affective evaluation. The purpose of our research is to process users' emotion and attention in real-time, with the goal of designing systems that may recognize a user's affective response to a particular visually presented stimulus in the presence of other stimuli, and respond accordingly. In this paper, we introduce the AutoSelect system that automatically detects a user's preference based on eye movement data and physiological signals in a two-alternative forced choice task. In an exploratory study involving the selection of neckties, the system could correctly classify subjects' choice of in 81%. In this instance of AutoSelect, the gaze ‘cascade effect' played a dominant role, whereas pupil size could not be shown as a reliable predictor of preference.\",\n \"Title: Would you like to play with me?: how robots' group membership and task features influence human-robot interaction\\nYear: 2014\\n\\nAbstract: In the present experiment, we investigated how robots' social category membership and characteristics of an HRI task affect humans' evaluative and behavioral reactions toward robots. Participants (N = 38) played a card game together with two robots, one belonging to participants' social in-group and the other one being a social out-group member. Furthermore, participants were either asked to cooperate with the in- and to compete with the out-group robot (congruent condition), or they were asked to cooperate with the out-group robot while competing with the in-group robot (incongruent condition). The results largely support our hypotheses: Participants showed more positive evaluative reactions toward the in-group (vs. the out-group) robot and they anthropomorphized it more strongly, independent of the congruency or incongruence of the HRI. Moreover, if required, participants cooperated with both the in- and the out-group robot, whereas their cooperativeness was more pronounced toward the in-group robot. Finally, participants indicated more difficulties with the HRI in the incongruent vs. the congruent condition. The theoretical and practical implications of the findings are discussed.\",\n \"Title: Getting the mobile users in: three systems that support collaboration in an environment with heterogeneous communication devices\\nYear: 2000\\n\\nAbstract: In this paper we present MapViews, Magic Lounge, and Call-Kiosk, three different but related systems that address the integration of mobile communication terminals into multi-user applications. MapViews is a test-bed to investigate how a small group of geographically dispersed users can jointly solve localization and route planning tasks while being equipped with different communication terminals. Magic Lounge is a virtual meeting space that provides a number of communication support services and allows its users to connect via heterogeneous devices. Finally, we sketch Call-Kiosk a system that is currently being designed for setting up a commercial information service for mobile clients. All three systems emphasize the high demand for automated design approaches which are able to generate information presentations that are tailored to the available presentation capabilities of particular target devices.\",\n \"Title: I Know What I Did Last Summer: Autobiographic Memory in Synthetic Characters\\nYear: 2007\\n\\nAbstract: According to traditional animators, the art of building believable characters resides in the ability to successfully portray a character's behaviour as the result of its internal emotions, intentions and thoughts. Following this direction, we want our agents to be able to explicitly talk about their internal thoughts and report their personal past experiences. In order to achieve it, we look at a specific type of episodic long term memory. This paper describes the integration of Autobiographic Memory into FAtiMA, an emotional agent architecture that generates emotions from a subjective appraisal of events.\",\n \"Title: Catch me if you can: exploring lying agents in social settings\\nYear: 2005\\n\\nAbstract: Embodied conversational agents become more and more realistic concerning their conversational and their nonverbal behaviors. But if the information conveyed nonverbally exhibits clues that are not consistent with the verbal part of an agent's action, how will the user react to such a discrepancy? Masking ones real emotions with a smile is a naturally occuring example of such a discrepancy. But such masks are often deficient and thus subtle clues of lying and deceiving manifest themselves in facial expressions. The questions is how users will react to these clues if they are conveyed by an agent. Will they render an application unattractive or on the contrary more human-like? In this paper, we examine such facial clues to deception and present the results of two empirical studies: i.) lies in monologues by a talking head presenting movies, ii.) lies in an interactive game of dice.\",\n \"Title: Where do they look?: Gaze behaviors of multiple users interacting with an embodied conversational agent\\nYear: 2005\\n\\nAbstract: In this paper, we describe an experiment we conducted to determine the user's level of engagement in a multi-party scenario consisting of human and synthetic interlocutors. In particular, we were interested in the question of whether humans accept a synthetic agent as a genuine conversational partner that is worthy of being attended to in the same way as the human interlocutors. We concentrated on gaze behaviors as one of the most important predictors of conversational attention.Surprisingly, humans paid more attention to an agent that talked to them than to a human conversational partner. No such effect was observed in the reciprocal case, namely when humans addressed an agent as opposed to a human interlocutor.\",\n \"Title: Sprache und Raum: Natürlichsprachlicher Zugang zu visuellen Daten\\nYear: 1990\\n\\nAbstract: Zusammenfassung Der vorliegende Beitrag befaßt sich mit der Reprasentation und Verarbeitung raumlich-zeitlichen Wissens im Hinblick auf den naturlichsprachlichen Zugang zu visuellen Daten. Im Kontext des Projektes Vitra, das sich mit der Entwicklung wissensbasierter Systeme zur Integration von maschinellem Sehen und der Ver- arbeitung naturlicher Sprache auseinandersetzt, soll diese Problemstellung naher diskutiert werden. Zunachst wird am Beispiel des Bildfolgenanalysesystems Ac- tions demonstriert, auf welche Weise Trajektorien bewegter Objekte aus Real- weltbildfolgen extrahiert werden konnen. Daran anschließend wird die in Vi- tra zugrundegelegte Schnittstelle zur Bildanalyse, die geometrische Szenenbe- schreibung, vorgestellt. Am Beispiel der lokalen orientierungsabhangigen Rela- tionenrechts, links, vor undhinter wird dann gezeigt, wie sich eine rein geometrische Darstellung in eine propositionale Beschreibung der raumlichen Anordnung ¨ uberfuhren laßt. Schließlich geht es um die Interpretation und Re- prasentation von Ereignissen, d.h. raumlich-zeitlichen Konzepten. Im Gegen- satz zu bisherigen Ansatzen soll dabei jedoch nicht von einer bereits vollstandig analysierten Bildfolge ausgegangen werden; vielmehr sind Ereignisse so zu re- prasentieren, daß sie simultan zu ihrem Auftreten in der Szene detektiert und naturlichsprachlich beschrieben werden konnen. Dieser Beitrag ist erschienen in: C. Freksa und C. Habel (Hrsg.), Reprasentation und Verarbeitung raumlichen Wissens, pp. 207-220. Berlin, Heidelberg: Sprin- ger, 1990.\",\n \"Title: The social signal interpretation (SSI) framework: multimodal signal processing and recognition in real-time\\nYear: 2013\\n\\nAbstract: Automatic detection and interpretation of social signals carried by voice, gestures, mimics, etc. will play a key-role for next-generation interfaces as it paves the way towards a more intuitive and natural human-computer interaction. The paper at hand introduces Social Signal Interpretation (SSI), a framework for real-time recognition of social signals. SSI supports a large range of sensor devices, filter and feature algorithms, as well as, machine learning and pattern recognition tools. It encourages developers to add new components using SSI's C++ API, but also addresses front end users by offering an XML interface to build pipelines with a text editor. SSI is freely available under GPL at http://openssi.net.\",\n \"Title: Hand distinction for multi-touch tabletop interaction\\nYear: 2009\\n\\nAbstract: Recent multi-touch multi-user tabletop systems offer rich touch contact properties to applications. Not only they provide touch positions, but also finger orientations. Applications can use these properties separated for each finger or derive information by combining the given touch contact data. In this paper, we present an approach to map fingers to their associated joined hand contributing to potential enhancements for gesture recognition and user interaction. For instance, a gesture can be composed of multiple fingers of one hand or different hands. Therefore, we present a simple heuristic for mapping fingers to hands that makes use of constraints applied to the touch position combined with the finger orientation. We tested our approach with collected diverse touch contact data and analyze the results.\",\n \"Title: Emotional Sensitivity In Human-Computer Interaction\\nYear: 2009\\n\\nAbstract: Human conversational partners usually try to interpret the speaker's or listener's affective cues and respond to them accordingly. Recently, the modelling and simulation of such behaviours has been recognized as an essential factor for more natural man-machine communication. The implicit emotion channels of human communication such as speech, facial expression, gesture, and physiological responses are used in general to extract emotion-relevant features for the computational perception of emotion. So far, research on emotion recognition has mostly dealt with offline analysis of recorded emotion corpora, and online processing (in realtime or near realtime) has hardly been addressed. Online processing is, however, a necessary prerequisite for the realization of human-computer interfaces that analyze and respond to the user's emotions while he or she is interacting with an application. In this paper, we first describe how we recognize emotions from various modalities including speech, gestures and biosignals. We then present Smart Sensor Integration (SSI), a framework which we developed to meet the specific requirements of online emotion recognition.\",\n \"Title: The Persona Effect: How Substantial Is It?\\nYear: 1998\\n\\nAbstract: Personification of interface agents has been speculated to have several advantages, such as a positive effect on agent credibility and on the perception of learning experience. However, important questions less often addressed so far are what effect personification has on more objective measures, such as comprehension and recall, and furthermore, under what circumstances this effect (if any) occurs. We performed an empirical study with adult participants to examine the effect of the Ppp Persona not only on subjective but also on objective measures. In addition, we tested it both with technical and non-technical domain information. The results of the study indicate that the data from the subjective measures support the so called persona effect for the technical information but not for non-technical information. With regard to the objective measures, however, neither a positive nor a negative effect could be found. Implications for software development are discussed.\",\n \"Title: Emotional input for character-based interactive storytelling\\nYear: 2009\\n\\nAbstract: In most Interactive Storytelling systems, user interaction is based on natural language communication with virtual agents, either through isolated utterances or through dialogue. Natural language communication is also an essential element of interactive narratives in which the user is supposed to impersonate one of the story's characters. Whilst techniques for narrative generation and agent behaviour have made significant progress in recent years, natural language processing remains a bottleneck hampering the scalability of Interactive Storytelling systems. In this paper, we introduce a novel interaction technique based solely on emotional speech recognition. It allows the user to take part in dialogue with virtual actors without any constraints on style or expressivity, by mapping the recognised emotional categories to narrative situations and virtual characters feelings. Our Interactive Storytelling system uses an emotional planner to drive characters' behaviours. The main feature of this approach is that characters' feelings are part of the planning domain and are at the heart of narrative representations. The emotional speech recogniser analyses the speech signal to produce a variety of features which can be used to define ad-hoc categories on which to train the system. The content of our interactive narrative is an adaptation of one chapter of the XIXth century classic novel, Madame Bovary, which is well suited to a formalisation in terms of characters' feelings. At various stages of the narrative, the user can address the main character or respond to her, impersonating her lover. The emotional category extracted from the user utterance can be analysed in terms of the current narrative context, which includes characters' beliefs, feelings and expectations, to produce a specific influence on the target character, which will become visible through a change in its behaviour, achieving a high level of realism for the interaction. A limited number of emotional categories is sufficient to drive the narrative across multiple courses of actions, since it comprises over thirty narrative functions. We report results from a fully implemented prototype, both in terms of proof of concept and of usability through a preliminary user study.\",\n \"Title: A cooperative in-car game for heterogeneous players\\nYear: 2011\\n\\nAbstract: Car rides are often perceived as dull by the passengers, especially children. Therefore, we aim to introduce a system fostering a collaborative and communicative experience in this environment. This paper presents the design for a game played together by all car-occupants, including the driver, according to their abilities and capacities. A fully implemented prototype of our system called nICE: nice In-Car Experience is evaluated under real world conditions in a user study with five families using a qualitative approach.\",\n \"Title: The IRIS Network of Excellence: Integrating Research in Interactive Storytelling\\nYear: 2008\\n\\nAbstract: Interactive Storytelling is a major endeavour to develop new media which could offer a radically new user experience, with a potential to revolutionise digital entertainment. European research in Interactive Storytelling has played a leading role in the development of the field, and this creates a unique opportunity to strengthen its position even further by structuring collaboration between some of its main actors. IRIS (Integrating Research in Interactive Storytelling) aims at creating a virtual centre of excellence that will be able to progress the understanding of fundamental aspects of Interactive Storytelling and the development of corresponding technologies.\",\n \"Title: Character roles and interaction in the DynaLearn intelligent learning environment\\nYear: 2011\\n\\nAbstract: In this paper we present the cast of pedagogical agents in the DynaLearn Intelligent Learning Environment. We describe the different character roles and how they interact with the learners. Our aim in using these characters is to increase the learners' motivation.\",\n \"Title: A systematic discussion of fusion techniques for multi-modal affect recognition tasks\\nYear: 2011\\n\\nAbstract: Recently, automatic emotion recognition has been established as a major research topic in the area of human computer interaction (HCI). Since humans express emotions through various channels, a user's emotional state can naturally be perceived by combining emotional cues derived from all available modalities. Yet most effort has been put into single-channel emotion recognition, while only a few studies with focus on the fusion of multiple channels have been published. Even though most of these studies apply rather simple fusion strategies -- such as the sum or product rule -- some of the reported results show promising improvements compared to the single channels. Such results encourage investigations if there is further potential for enhancement if more sophisticated methods are incorporated. Therefore we apply a wide variety of possible fusion techniques such as feature fusion, decision level combination rules, meta-classification or hybrid-fusion. We carry out a systematic comparison of a total of 16 fusion methods on different corpora and compare results using a novel visualization technique. We find that multi-modal fusion is in almost any case at least on par with single channel classification, though homogeneous results within corpora point to interchangeability between concrete fusion schemes.\",\n \"Title: EVAL - an evaluation component for mobile interfaces\\nYear: 2008\\n\\nAbstract: The Eval Tool is a usability evaluation environment which can be used to evaluate users an their behaviour while they interact with their pervasive computing environment via a mobile phone interface. The tool supports audio-visual recordings of several users and automatically annotates and synchronizes them with context data emerging from the pervasive environment. The annotation of video material with contextual information is important for the analysis of user studies and the detection of usability issues. The EVAL Tool consists of a recorder and a analyzer component. Using the recorder component the capturing of the videos and the logging of the context can be controlled whereas the analyzer components helps to interpret the user study.\",\n \"Title: Zur multimedialen Präsentation von Handlungsalternativen in Verkehrsmanagement- und Verkehrssimulationssystemen\\nYear: 1998\\n\\nAbstract: Eine pr?gnante und zugleich wirkungsvolle Informationspr?sentation l??t sich vielfach nur durch den Einsatz unterschiedlicher Medien erzielen, insbesondere durch aufeinander abgestimmte Medienkombinationen, wie illustrierte Texte, oder sprachlich begleitete Animationen. Geteilt wird diese Einsch?tzung auch zunehmend von Entwicklern sog. Entscheidungsunterstützungssysteme (EUS), die heute verbreitet zur Bew?ltigung von Transport/Verkehrsmanagementaufgaben zum Einsatz kommen. Komplexe Pr?sentationsaufgaben mit hoher Datenvarianz sind in solchen Systemen jedoch ohne Einsatz intelligenter Verfahren zur Generierung multimedialer Pr?sentationen kaum mehr zu bew?ltigen. Der vorliegende Beitrag thematisiert das Pr?sentationsproblem in zeitkritischen Anwendungen. Anhand eines konkreten Einsatzszenarios im Bereich der Verkehrsüberwachung,-simulation und-steuerung wird ein Ansatz zur automatischen Pr?sentationsgestaltung aufgezeigt. Eine Besonderheit des Ansatzes ist sein Verm?gen, mitzuteilende Handlungsalternativen durch geeignete Medienkombinationen in aggregierter Form darzubieten.\",\n \"Title: Surface-poker: multimodality in tabletop games\\nYear: 2010\\n\\nAbstract: Multimodal interaction and face-to-face communication between players are aspects of traditional board games which contribute to their popularity. Such aspects are also typical of digital tabletop games. But in addition to that, digital systems allow for a higher level of multimodality through utilizing novel interaction devices or physiological input data. In this paper, we describe a multimodal tabletop Poker game which makes use of both: additional interaction devices and physiological input data. We outline the tabletop game, the interaction modalities involved, and observations of players.\",\n \"Title: Studying user-defined iPad gestures for interaction in multi-display environment\\nYear: 2012\\n\\nAbstract: The paper investigates the iPad gestures that users naturally perform for data transfer. We examine the transfer between two iPads, iPad and a tabletop, and iPad and a public display. Three gesture modalities are investigated: multi-touch gestures, performed using iPad display, spatial gestures, performed by manipulating iPad in 3D space, and direct contact gestures, involving the physical contact of iPad and other device. We report on user choices of the modalities and gesture types, and derive critical points for the design of iPad gestures.\",\n \"Title: Let's come together: social navigation behaviors of virtual and real humans\\nYear: 2005\\n\\nAbstract: In this paper, we present a game-like scenario that is based on a model of social group dynamics inspired by theories from the social sciences. The model is augmented by a model of proxemics that simulates the role of distance and spatial orientation in human-human communication. By means of proxemics, a group of human participants may signal other humans whether they welcome new group members to join or not. In this paper, we describe the results of an experiment we conducted to shed light on the question of how humans respond to such cues when shown by virtual humans.\",\n \"Title: Modeling parallel state charts for multithreaded multimodal dialogues\\nYear: 2011\\n\\nAbstract: In this paper, we present a modeling approach for the management of highly interactive, multithreaded and multimodal dialogues. Our approach enforces the separation of dialogue content and dialogue structure and is based on a statechart language enfolding concepts for hierarchy, concurrency, variable scoping and a detailed runtime history. These concepts facilitate the modeling of interactive dialogues with multiple virtual characters, autonomous and parallel behaviors, flexible interruption policies, context-sensitive interpretation of the user's discourse acts and coherent resumptions of dialogues. An interpreter allows the realtime visualization and modification of the model to allow a rapid prototyping and easy debugging. Our approach has successfully been used in applications and research projects as well as evaluated in field tests with non-expert authors. We present a demonstrator illustrating our concepts in a social game scenario.\",\n \"Title: Discovering eye gaze behavior during human-agent conversation in an interactive storytelling application\\nYear: 2010\\n\\nAbstract: In this paper, we investigate the user's eye gaze behavior during the conversation with an interactive storytelling application. We present an interactive eye gaze model for embodied conversational agents in order to improve the experience of users participating in Interactive Storytelling. The underlying narrative in which the approach was tested is based on a classical XIXth century psychological novel: Madame Bovary, by Flaubert. At various stages of the narrative, the user can address the main character or respond to her using free-style spoken natural language input, impersonating her lover. An eye tracker was connected to enable the interactive gaze model to respond to user's current gaze (i.e. looking into the virtual character's eyes or not). We conducted a study with 19 students where we compared our interactive eye gaze model with a non-interactive eye gaze model that was informed by studies of human gaze behaviors, but had no information on where the user was looking. The interactive model achieved a higher score for user ratings than the non-interactive model. In addition we analyzed the users' gaze behavior during the conversation with the virtual character.\",\n \"Title: Influence of head orientation in perception of personality traits in virtual agents\\nYear: 2011\\n\\nAbstract: The aim of this research is to explore the influence of static visual cues on the perception of a character's personality traits: extraversion, agreeableness and emotional stability. To measure how users perceived personality, we conducted a web-based study with 133 subjects who rated 54 images of a virtual character with varying head orientations and gaze.\",\n \"Title: Traveller: an intercultural training system with intelligent agents\\nYear: 2013\\n\\nAbstract: There is a growing demand for new forms of intercultural training. We describe a demonstration of an agent-based application designed to teach young adults (18-25) general patterns of behaviour that can distinguish a broad range of cultures. Training is done through an interactive-story telling approach where the user must go through a series of critical incidents, interacting with agents capable of simulating different synthetic cultures in their behaviour.\",\n \"Title: Friend or foe? relationship-based adaptation on public displays\\nYear: 2011\\n\\nAbstract: Personalization of content on public displays is likely to cause the disclosure of user's private data. In order to protect the user's privacy, different protection strategies are used, e.g. the private data is hidden, occluded or blurred. Existing systems usually follow a uniform protection strategy, applying it every time a spectator is detected in the display proximity. However, the necessity in privacy protection often depends on the personal relationships between the user and the spectator. This work investigates how the relationship context influences user preferences in adaptation strategies. Additionally, we study how privacy level of data and the presence of a mobile device influence this preference. The obtained results can guide adaptation designers in creation of more flexible privacy protection mechanisms.\",\n \"Title: Mobile augmented reality and adaptive art: a game-based motivation for energy saving\\nYear: 2012\\n\\nAbstract: We present the design of an educational treasure hunt game that uses mobile Augmented Reality (AR) and adaptive virtual gardens to raise awareness on energy consumption ways. Within the game, AR is used to present 3D content that allows for visually understanding the energy consumption problems and their solutions. In addition, the players' performances are given in a form of a visual feedback as dynamic virtual gardens that change from poor to good status. Initial tests show that the presented game is highly appealing to players and motivated them to be aware of the presented problem using AR technologies and the visual effects of their virtual garden's health. Future work will focus on evaluating the learnability and engagement of players.\",\n \"Title: Enculturating conversational interfaces by socio-cultural aspects of communication\\nYear: 2008\\n\\nAbstract: The workshop is centered around three main research challenges: 1.) Computationally viable models of cultural aspects of conversations: Cultural norms and values penetrate all our communications and interactions by giving us heuristics how to behave and how to interpret the verbal and nonverbal behavior of others. To make such a notion like culture available for computation, we need a very specific theory of culture that takes its effects on communication and interaction into account.2.) Reliable empirical data on cultural/cross-cultural interaction: To realize technical systems that take cultural influences on behavior into account, precise data analysis on how this influence manifests itself is necessary. In the literature, this information is often given in very general forms without to the precise data on which the observations are based.3.) Enculturating conversational interfaces: Having identified cultural influences on verbal/nonverbal communicative behaviors, it remains to be shown how this can be applied to the development of human-computer interfaces, for instance in an interface reflecting cultural norms and values of communication.\",\n \"Title: Incremental Natural Language Description of Dynamic Imagery\\nYear: 1989\\n\\nAbstract: Although image understanding and natural language processing constitute two major areas of AI, they have mostly been studied independently of each other. Only a few attempts have been concerned with the integration of computer vision and the generation of natural language expressions for the description of image sequences.\",\n \"Title: A Generate-And-Sense Approach To Automated Music Composition\\nYear: 2005\\n\\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user-specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.\",\n \"Title: A generate and sense approach to automated music composition\\nYear: 2004\\n\\nAbstract: Nobody would deny that music may evoke deep and profound emotions. In this paper, we present a perceptual music composition system that aims at the controlled manipulation of a user's emotional state. In contrast to traditional composing techniques, the single components of a composition, such as melody, harmony, rhythm and instrumentation, are selected and combined in a user-specific manner without requiring the user to continuously provide comments on the music employing input devices, such as keyboard or mouse.\",\n \"Title: Architecture of a ubiquitous smart energy management system for residential homes\\nYear: 2011\\n\\nAbstract: A range of technology for monitoring electricity consumption at residential homes is gradually becoming available to users. Almost all of these systems, however, only aim to assist users with reducing their total power consumption, without being concerned too much about how those savings are actually made. Our research, aims to provide a basis for design of systems that give users control over management of power usage, so that savings in energy consumption can be made more intelligently. This paper describes the requirements of such a system, and proposes an architecture for these types of ubiquitous systems for residential homes.\",\n \"Title: Presenting through performing: on the use of multiple lifelike characters in knowledge-based presentation systems\\nYear: 2000\\n\\nAbstract: In this paper, we investigate a new style for presenting information. We introduce the motion of presentation teams which — rather than addressing the user directly — convey information in the style of performances to be observed by him or her. The paper presents an approach to the automated generation of performances which has been tested in two different application scenarios, car sales dialogues and soccer commentary.\",\n \"Title: A Framework for User-Defined Body Gestures to Control a Humanoid Robot.\\nYear: 2014\\n\\nAbstract: This paper presents a framework that allows users to interact with and navigate a humanoid robot using body gestures. The first part of the paper describes a study to define intuitive gestures for eleven navigational commands based on analyzing 385 gestures performed by 35 participants. From the study results, we present a taxonomy of the user-defined gesture sets, agreement scores for the gesture sets, and time performances of the gesture motions. The second part of the paper presents a full body interaction system for recognizing the user-defined gestures. We evaluate the system by recruiting 22 participants to test for the accuracy of the proposed system. The results show that most of the defined gestures can be successfully recognized with a precision between 86100 % and an accuracy between 7396 %. We discuss the limitations of the system and present future work improvements.\",\n \"Title: XIM-engine: a software framework to support the development of interactive applications that uses conscious and unconscious reactions in immersive mixed reality\\nYear: 2014\\n\\nAbstract: The development of systems that allow multimodal interpretation of human-machine interaction is crucial to advance our understanding and validation of theoretical models of user behavior. In particular, a system capable of collecting, perceiving and interpreting unconscious behavior can provide rich contextual information for an interactive system. One possible application for such a system is in the exploration of complex data through immersion, where massive amounts of data are generated every day both by humans and computer processes that digitize information at different scales and resolutions thus exceeding our processing capacity. We need tools that accelerate our understanding and generation of hypotheses over the datasets, guide our searches and prevent data overload. We describe XIM-engine, a bio-inspired software framework designed to capture and analyze multi-modal human behavior in an immersive environment. The framework allows performing studies that can advance our understanding on the use of conscious and unconscious reactions in interactive systems.\",\n \"Title: Augmenting Social Interactions: Realtime Behavioural Feedback using Social Signal Processing Techniques\\nYear: 2015\\n\\nAbstract: Nonverbal and unconscious behaviour is an important component of daily human-human interaction. This is especially true in situations such as public speaking, job interviews or information sensitive conversations, where researchers have shown that an increased awareness of one's behaviour can improve the outcome of the interaction. With wearable technology, such as Google Glass, we now have the opportunity to augment social interactions and provide realtime feedback on one's behaviour in an unobtrusive way. In this paper we present Logue, a system that provides realtime feedback on the presenters' openness, body energy and speech rate during public speaking. The system analyses the user's nonverbal behaviour using social signal processing techniques and gives visual feedback on a head-mounted display. We conducted two user studies with a staged and a real presentation scenario which yielded that Logue's feedback was perceived helpful and had a positive impact on the speaker's performance.\",\n \"Title: Modeling Gaze Mechanisms for Grounding in HRI.\\nYear: 2014\\n\\nAbstract: Grounding is essential in human interaction and crucial for social robots collaborating with humans. Gaze plays versatile roles for establishing, maintaining and repairing the common ground. It is combined with parallel modalities and involved in several processes for behavior generation and recognition. We present a uniform modeling approach focusing on the multi-modal, parallel and bidirectional aspects of gaze and their interleaving with the dialog logic.\",\n \"Title: An Event Driven Fusion Approach for Enjoyment Recognition in Real-time\\nYear: 2014\\n\\nAbstract: Social signals and interpretation of carried information is of high importance in Human Computer Interaction. Often used for affect recognition, the cues within these signals are displayed in various modalities. Fusion of multi-modal signals is a natural and interesting way to improve automatic classification of emotions transported in social signals. Throughout most present studies, uni-modal affect recognition as well as multi-modal fusion, decisions are forced for fixed annotation segments across all modalities. In this paper, we investigate the less prevalent approach of event driven fusion, which indirectly accumulates asynchronous events in all modalities for final predictions. We present a fusion approach, handling short-timed events in a vector space, which is of special interest for real-time applications. We compare results of segmentation based uni-modal classification and fusion schemes to the event driven fusion approach. The evaluation is carried out via detection of enjoyment-episodes within the audiovisual Belfast Story-Telling Corpus.\",\n \"Title: A framework for the development of multi-display environment applications supporting interactive real-time portals\\nYear: 2014\\n\\nAbstract: Advances in multi-touch enabled interactive tabletops led to many commercially available products and were increasingly deployed at places beyond research labs, for example at exhibitions, retail stores, or showrooms. At the same time, small multi-touch devices, such as tablets or smartphones, became prevalent in our daily life. When considering both trends, occasions and scenarios where tabletop systems and mobile devices form a coupled interaction space are expected to become increasingly widespread. However, application development or research prototypes for those environments will foreseeable require considerable resources when considering nowadays heterogeneity of device platforms and the functionality to establish a connected interaction space. To address these concerns, this paper discusses challenges and answers questions that arose during design and implementation of the Environs framework, a multi-display environment software framework that eases development of interactive distributed applications. In particular, Environs enables applications utilizing video portals that put high requirements on responsiveness and latency.\",\n \"Title: A Multi-Display System for Deploying and Controlling Home Automation\\nYear: 2014\\n\\nAbstract: In this paper, we present a concept of using a home devices mashup tool to wire home devices on a tabletop display in combination with web based UIs on mobile devices to control home devices. This concept is realized by a multi-display system supported by the open-source framework Environs. The mashup tool on the tabletop enables multiple people to deploy home networked devices co-located collaboratively with a more natural and intuitive interface. Moreover, web based UIs on mobile devices enable individuals to control home devices universally with high accessibility and mobility.\",\n \"Title: Challenges for Social Embodiment\\nYear: 2014\\n\\nAbstract: Current research in the area of social signal processing focuses on offline analysis of previously recorded human social cues. Approaches to exploit social signal processing techniques in naturalistic environments where agents socially interact with humans are rare and typically focus on isolated aspects, such as the creation of appropriate head nods or gaze behaviors. This position paper aims to identify challenges and research objectives for the area of social signal processing in order to encourage applications with more advanced forms of social embodiment in interactive settings.\",\n \"Title: Exploring a Model of Gaze for Grounding in Multimodal HRI\\nYear: 2014\\n\\nAbstract: Grounding is an important process that underlies all human interaction. Hence, it is crucial for building social robots that are expected to collaborate effectively with humans. Gaze behavior plays versatile roles in establishing, maintaining and repairing the common ground. Integrating all these roles in a computational dialog model is a complex task since gaze is generally combined with multiple parallel information modalities and involved in multiple processes for the generation and recognition of behavior. Going beyond related work, we present a modeling approach focusing on these multi-modal, parallel and bi-directional aspects of gaze that need to be considered for grounding and their interleaving with the dialog and task management. We illustrate and discuss the different roles of gaze as well as advantages and drawbacks of our modeling approach based on a first user study with a technically sophisticated shared workspace application with a social humanoid robot.\",\n \"Title: Modeling Grounding for Interactive Social Companions\\nYear: 2016\\n\\nAbstract: Grounding is an important process that underlies all human interaction. Hence, it is also crucial for social companions to interact naturally. Maintaining the common ground requires domain knowledge but has also numerous social aspects, such as attention, engagement and empathy. Integrating these aspects and their interplay with the dialog management in a computational interaction model is a complex task. We present a modeling approach overcoming this challenge and illustrate it based on some social companion applications.\",\n \"Title: A cross-cultural, multimodal, affective corpus for gesture expressivity analysis\\nYear: 2013\\n\\nAbstract: A multimodal, cross-cultural corpus of affective behavior is presented in this research work. The corpus construction process, including issues related to the design and implementation of an experiment, is discussed along with resulting acoustic prosody, facial expressions and gesture expressivity features. However, research work presented here focuses more on the cross-cultural aspect of gestural behavior defining a common corpus construction protocol aiming to identify cultural patterns within non-verbal behavior across cultures i.e. German, Greek and Italian. Culture specific findings regarding gesture expressivity are derived from the affective analysis performed. Additionally, the multimodal aspect, including prosody and facial expressions, is researched in terms of fusion techniques. Finally, a release plan of the corpus to the public domain is discussed aiming to establish the current corpus as a benchmark multimodal, cross-cultural standard and reference point.\",\n \"Title: Context-Aware Automated Analysis and Annotation of Social Human--Agent Interactions\\nYear: 2015\\n\\nAbstract: The outcome of interpersonal interactions depends not only on the contents that we communicate verbally, but also on nonverbal social signals. Because a lack of social skills is a common problem for a significant number of people, serious games and other training environments have recently become the focus of research. In this work, we present NovA (Nonverbal behavior Analyzer), a system that analyzes and facilitates the interpretation of social signals automatically in a bidirectional interaction with a conversational agent. It records data of interactions, detects relevant social cues, and creates descriptive statistics for the recorded data with respect to the agent's behavior and the context of the situation. This enhances the possibilities for researchers to automatically label corpora of human--agent interactions and to give users feedback on strengths and weaknesses of their social behavior.\",\n \"Title: Trust-based decision-making for smart and adaptive environments\\nYear: 2015\\n\\nAbstract: Smart environments are able to support users during their daily life. For example, smart energy systems can be used to support energy saving by controlling devices, such as lights or displays, depending on context information, such as the brightness in a room or the presence of users. However, proactive decisions should also match the users’ preferences to maintain the users’ trust in the system. Wrong decisions could negatively influence the users’ acceptance of a system and at worst could make them abandon the system. In this paper, a trust-based model, called User Trust Model (UTM), for automatic decision-making is proposed, which is based on Bayesian networks. The UTM’s construction, the initialization with empirical data gathered in an online survey, and its integration in an office setting are described. Furthermore, the results of a live study and a live survey analyzing the users’ experience and acceptance are presented.\",\n \"Title: Open Challenges in Modelling, Analysis and Synthesis of Human Behaviour in Human–Human and Human–Machine Interactions\\nYear: 2015\\n\\nAbstract: Modelling, analysis and synthesis of behaviour are the subject of major efforts in computing science, especially when it comes to technologies that make sense of human–human and human–machine interactions. This article outlines some of the most important issues that still need to be addressed to ensure substantial progress in the field, namely (1) development and adoption of virtuous data collection and sharing practices, (2) shift in the focus of interest from individuals to dyads and groups, (3) endowment of artificial agents with internal representations of users and context, (4) modelling of cognitive and semantic processes underlying social behaviour and (5) identification of application domains and strategies for moving from laboratory to the real-world products.\",\n \"Title: Natural interaction with culturally adaptive virtual characters\\nYear: 2012\\n\\nAbstract: Recently, the verbal and non-verbal behavior of virtual characters has become more and more sophisticated due to advances in behavior planning and rendering. Nevertheless, the appearance and behavior of these characters is in most cases based on the cultural background of their designers. Especially in combination with new natural interaction interfaces, there is the risk that characters developed for a particular culture might not find acceptance when being presented to another culture. A few attempts have been made to create characters that reflect a particular cultural background. However, interaction with these characters still remains an awkward experience in particular when it comes to non-verbal interaction. In many cases, human users either have to choose actions from a menu their avatar has to execute or they have to struggle with obtrusive interaction devices. In contrast, our paper combines an approach to the generation of culture-specific behaviors with full body avatar control based on the Kinect sensor. A first study revealed that users are able to easily control an avatar through their body movements and immediately adapt its behavior to the cultural background of the agents they interact with.\",\n \"Title: The Belfast storytelling database: A spontaneous social interaction database with laughter focused annotation\\nYear: 2015\\n\\nAbstract: To support the endeavor of creating intelligent interfaces between computers and humans the use of training materials based on realistic human-human interactions has been recognized as a crucial task. One of the effects of the creation of these databases is an increased realization of the importance of often overlooked social signals and behaviours in organizing and orchestrating our interactions. Laughter is one of these key social signals; its importance in maintaining the smooth flow of human interaction has only recently become apparent in the embodied conversational agent domain. In turn, these realizations require training data that focus on these key social signals. This paper presents a database that is well annotated and theoretically constructed with respect to understanding laughter as it is used within human social interaction. Its construction, motivation, annotation and availability are presented in detail in this paper.\",\n \"Title: Socially-Sensitive Interfaces: From Offline Studies to Interactive Experiences.\\nYear: 2016\\n\\nAbstract: Recent years have initiated a paradigm shift from pure taskbased human-machine interfaces towards socially-sensitive interaction. In addition to what users explicitly say or gesture at, socially-sensitive interfaces are able to sense more subtle human cues, such as head postures and movements, to infer psychological user states, such as attention and affect, and also to enrich system responses with social signals. However, most approaches focus on offline analysis of previously recorded data limiting the investigation to prototypical behaviors in laboratory-like settings. In my presentation, I will focus on challenges that arise when integrating social signal processing techniques into interactive systems designed for real-world applications. From a technical perspective, this requires effective tools able to synchronize, process, and analyze relevant signals in online mode. From a user perspective, appropriate strategies need to be defined to respond to social signals at the right moment in time without disturbing the flow of interaction. I will discuss two interaction styles for socially-sensitive interfaces. In the area of information retrieval, the concept of empathic stimulation has been used to optimize the selection and presentation of data. The basic idea is to exploit sensory data on the users' emotional state to provide them with cues that inspire their curiosity during the data exploration task. In the domain of social coaching, the concept of social augmentation has been employed to give people ambient feedback on their behavior while being engaged in a social interaction. The presentation will be illustrated by examples from various national and international projects following these two interaction styles.\",\n \"Title: Combining Hierarchical Classification With Frequency Weighting For The Recognition Of Eating Conditions\\nYear: 2015\\n\\nAbstract: Though parents regularly remind their children not to do so, talking while eating is a typical everyday situation automatic speech analysis systems should be able to deal with. The Paralinguistic Eating Condition (EC) Challenge at INTERSPEECH 2015 sets the task to classify whether a speaker is eating or not, and if so, which type of food the speaker is currently tasting. The approach we follow in this paper is rather unusual: instead of suppressing the influence of noise to enhance the intelligibility of a spoken message, we try to emphasize the noisy parts of the spectrum to improve the recognition of food classes. To allow for a fine-grained adaption to the characteristic spectrum of single food types we adopt a hierarchical tree structure and decompose the classification task into a sequence of binary decisions. At each node we apply frequency-dependent weighting to tune the spectrum to the involved target classes. With our approach we are able to improve results in a 7-class recognition problem (6 types of food and no food) by more than 7% on the training set (using leave-one-eater-out cross validation) and 4% on the test set, respectively.\",\n \"Title: Games Are Better Than Books: In-Situ Comparison Of An Interactive Job Interview Game With Conventional Training\\nYear: 2015\\n\\nAbstract: Technology-enhanced learning environments are designed to help users practise social skills. In this paper, we present and evaluate a virtual job interview training game which has been adapted to the special requirements of young people with low chances on the job market. The evaluation spanned three days, during which we compared the technology-enhanced training with a traditional learning method usually practised in schools, i.e. reading a job interview guide. The results are promising as professional career counsellors rated the pupils who trained with the system significantly better than those who learned with the traditional method.\",\n \"Title: Exploring Digital Image Frames for Lifestyle Intervention to Improve Well-being of Older Adults\\nYear: 2015\\n\\nAbstract: This contribution addresses the development of technology for senior users with the aim to improve their general wellbeing. We present a prototype system named CARE that is used for in-situ testing in a senior's home and combines functionality of a digital image frame with an active recommender mode. The purpose of the recommender is to provide the user with context-specific recommendations. Recommendations are chosen on the basis of sensor data and a well-being model to carefully decide on at which point in time what kind of activity will be most suitable to suggest.\",\n \"Title: Modeling and Evaluating a Bayesian Network of Culture-Dependent Behaviors\\nYear: 2015\\n\\nAbstract: Anthropomorphic user interfaces such as virtual agents or humanoid robots aim on simulating believable human behavior. As human behavior is influenced by diversifying factors such as cultural background, research in anthropomorphic user interfaces considers culture background for their behavioral models as well. This paper presents a hybrid approach of creating a culture-specific model of non-verbal behaviors for simulated dialogs based on both: theoretical knowledge and empirical data. Therefore, the structure and variables of a Bayesian network are designed based on models and theories from the social sciences, while its parameters are learned from a video corpus of German and Japanese conversations in first time meeting scenarios. To validate the model a 10-fold-cross-validation has been conducted, suggesting that with the model culture-specific behavior can automatically be generated for some of the investigated behavioral aspects.\",\n \"Title: Investigating Politeness Strategies and Their Persuasiveness for a Robotic Elderly Assistant.\\nYear: 2016\\n\\nAbstract: This work is targeted towards the development of a Robotic Elderly Assistant REA system that provides assistance in the form of recommendations to support single-living elderly people in their domestic environment. To avoid potential face threats the REA should be as polite as possible whilst keeping a certain persuasiveness to promote its recommendations. This paper investigates different verbalizations of the REA's recommendations regarding their perceived politeness as well as their persuasiveness. We present the results of a laboratory study with younger adults and a user study with the inhabitants of a retirement home. Results suggest that the different politeness strategies reflected different levels of politeness in both studies, while their perceived persuasiveness needs further investigation in the domain of elderly care.\",\n \"Title: Fostering Smart Energy Applications\\nYear: 2015\\n\\nAbstract: There is an increasing need for smart applications with interactive visual interfaces that allow users to better manage and monitor their energy generation and consumption. This workshop will bring together researchers and practitioners from interaction design, human-computer interaction, visualization, computer games, and media technology to foster research, design, development, and deployment of energy-related applications, tools, services, games, and persuasive technologies.\",\n \"Title: Exploring the Potential of Realtime Haptic Feedback during Social Interactions.\\nYear: 2016\\n\\nAbstract: We explore the use of haptic feedback to deliver supportive information during social interactions in realtime. In an exploratory user study, we investigated perceptual limitations of vibration patterns during a conversation between peers. The results from this study have then been used to develop a system for providing users with realtime information regarding the quality of their nonverbal behaviour while engaged in a public speech.\",\n \"Title: How Can I Interact?: Comparing Full Body Gesture Visualizations\\nYear: 2015\\n\\nAbstract: This paper is dedicated to the question \\\\\\\"How can I interact?\\\\\\\", which may arise during a full body interaction game. To answer this question, a game needs to tell the players what actions are available and how those actions can be triggered. We focus on the video channel and use onscreen symbols to visualize how available input gestures have to be performed. We describe three symbol variants using recordings of a real person: color images, tracking shapes and skeletons, and solely tracking skeletons. An initial evaluation study shows clear advantages for the color images. We further outline how we extend the current implementation, for both improving the usability of the symbols, as well as easing their development.\",\n \"Title: Visualization Support for Comparing Energy Consumption Data\\nYear: 2015\\n\\nAbstract: Providing effective feedback can empower users to change their behaviour and take the necessary actions to reduce their energy consumption. The types of feedback that allow comparison of energy usage seem to be particularly valuable. This paper introduces the time-stack visualization, which has been designed to support comparisons of individual and collective energy usage data. It also describes a user study conducted to compare the effectiveness of time-stack against a similar visualization called time-pie. The results show that although the two visualizations are generally comparable in their effectiveness, users rate time-stack more favourably.\",\n \"Title: Exploring Eye-Tracking-Driven Sonification for the Visually Impaired.\\nYear: 2016\\n\\nAbstract: Most existing sonification approaches for the visually impaired restrict the user to the perception of static scenes by performing sequential scans and transformations of visual information to acoustic signals. This takes away the user's freedom to explore the environment and to decide which information is relevant at a given point in time. As a solution, we propose an eye tracking system to allow the user to choose which elements of the field of view should be sonified. More specifically, we enhance the sonification approaches for color, text and facial expressions with eye tracking mechanisms. To find out how visually impaired people might react to such a system we applied a user centered design approach. Finally, we explored the effectiveness of our concept in a user study with seven visually impaired persons. The results show that eye tracking is a very promising input method to control the sonification, but the large variety of visual impairment conditions restricts the applicability of the technology.\",\n \"Title: Design of a lifestyle recommender system for the elderly: requirement gatherings in Germany and Greece\\nYear: 2015\\n\\nAbstract: As overaging is becoming a main societal challenge, the development of AAL (Ambient Assisted Living) systems has become the centre of many research projects the last years. Our own work is targeted towards the development of an AAL system -called CARE- that provides assistance in form of recommendations helping its users overcome typical difficulties of everyday life, and contributes positively to their well-being. To inform the design of the envisioned CARE system we recruited two peer groups of potential users, a group of 20 Greek seniors, and a group of 27 German seniors, and conducted structured interviews which were focused on the seniors' life-style, medical needs, attitude towards AAL technologies, and, more specifically, on desired functions and system configurations of a recommendation-giving CARE system. We discuss outcomes of the conducted interviews and sketch a first CARE prototype which appears as an augmented digital picture frame that interleaves the display of photos with recommendations and interventions to improve the seniors' life-style and well-being.\",\n \"Title: Stress Recognition in Daily Work.\\nYear: 2015\\n\\nAbstract: Automatic detection of work-related stress has attracted an increasing amount of attention from researchers from various disciplines and industries. An experiment is discussed in this paper that was designed to evaluate the efficacy of multimodal sensor measures that have often been used but not yet been systematically tested and compared with each other in previous work, such as pressure distribution sensor, physiological sensors, and an eye tracker. We used the Stroop test and information pick up task as the stressors. In the subject independent case in particular, signals from the combined (chair and floor) pressure distribution sensors, which we consider the most feasible sensors in the office environment, resulted in higher recognition accuracy rates than the physiological or eye tracker signals for the two stressors.\",\n \"Title: Exploring Eye-Tracking-Based Detection of Visual Search for Elderly People\\nYear: 2016\\n\\nAbstract: Visual search plays an important role in our daily lives and can be very frustrating whenever we cannot remember where we left objects, such as keys or wallets. This is especially true for elderly people, since they forget things more often and face this challenge very frequently. While there are several studies which analyze eye movements during visual search, none of them actually tries to detect whether a user is searching for something or not. However, this information is necessary to recognize when the user needs assistance. Therefore, we propose an eye-tracking-based multimodal approach in order to detect visual search and to support the user in that situation. Furthermore, we explore multiple strategies to inform the user of the desired object's location using a head mounted display. With the help of a prototypical implementation and evaluation of the acquired sensor data, we show that our method is feasible and capable of dealing with this challenge.\",\n \"Title: MobileSSI - A Multi-modal Framework for Social Signal Interpretation on Mobile Devices\\nYear: 2016\\n\\nAbstract: Over the last years, new generations of mobile devices have found their way into our pockets. They provide more and more computational power and memory capacity to perform complex calculations that formerly could only be accomplished with bulky desktop machines. Moreover, mobile devices are equipped with a range of sensors to capture people's motion, environmental sound etc. These capabilities combined with the willingness of people to permanently carry them around open up completely new ways of observing human behaviour no longer in laboratories, but \\\"in the wild\\\". However, the detection and analysis of social cues is still a challenging task and requires adequate tools to synchronise, process and analyse relevant signals. This may be the reason why many studies and applications focus on offline analysis and typically collect data over long periods of time and analyse them afterwards. To allow for immediate feedback, real-time assessment is necessary. In this paper, we present MobileSSI, a port of the Social Signal Interpretation (SSI) framework to Android and embedded Linux platforms. The framework supports the joint development of processing pipelines for the analysis of social signals on a desktop computer and mobile devices. Throughout the paper we report on challenges we had to face when porting SSI to a mobile context. Furthermore, we summarise first experiences with a real-life setting in a pub where we focused on the analysis of multimodal social group dynamics investigating laughter as a sign of enjoyment.\",\n \"Title: Ask Alice: an artificial retrieval of information agent.\\nYear: 2016\\n\\nAbstract: We present a demonstration of the ARIA framework, a modular approach for rapid development of virtual humans for information retrieval that have linguistic, emotional, and social skills and a strong personality. We demonstrate the framework's capabilities in a scenario where `Alice in Wonderland', a popular English literature book, is embodied by a virtual human representing Alice. The user can engage in an information exchange dialogue, where Alice acts as the expert on the book, and the user as an interested novice. Besides speech recognition, sophisticated audio-visual behaviour analysis is used to inform the core agent dialogue module about the user's state and intentions, so that it can go beyond simple chat-bot dialogue. The behaviour generation module features a unique new capability of being able to deal gracefully with interruptions of the agent.\",\n \"Title: Social signal processing for dummies.\\nYear: 2016\\n\\nAbstract: We introduce SSJ Creator, a modern Android GUI enabling users to design and execute social signal processing pipelines using nothing but their smartphones and without writing a single line of code. It is based on a modular Java-based social signal processing framework (SSJ), which is able to perform realtime multimodal behaviour analysis on Android devices using both device internal and external sensors.\",\n \"Title: MobileSSI: asynchronous fusion for social signal interpretation in the wild.\\nYear: 2016\\n\\nAbstract: Over the last years, mobile devices have become an integral part of people's everyday life. At the same time, they provide more and more computational power and memory capacity to perform complex calculations that formerly could only be accomplished with bulky desktop machines. These capabilities combined with the willingness of people to permanently carry them around open up completely new perspectives to the area of Social Signal Processing. To allow for an immediate analysis and interaction, real-time assessment is necessary. To exploit the benefits of multiple sensors, fusion algorithms are required that are able to cope with data loss in asynchronous data streams. In this paper we present MobileSSI, a port of the Social Signal Interpretation (SSI) framework to Android and embedded Linux platforms. We will test to what extent it is possible to run sophisticated synchronization and fusion mechanisms in an everyday mobile setting and compare the results with similar tasks in a laboratory environment.\",\n \"Title: Laughter detection in the wild: demonstrating a tool for mobile social signal processing and visualization.\\nYear: 2016\\n\\nAbstract: In this demo, we present MobileSSI, a flexible software framework for Android and embedded Linux platforms, that provides developers with tools to record, analyze and recognize human behavior in real-time on mobile devices. To illustrate the benefits of the framework for the analysis of social group dynamics in naturalistic mobile settings, we present a demonstrator for laughter recognition that was implemented with MobileSSI. The demonstrator makes use of smartphones for sensing and analyzing data and employs smartwatches and tablets for visualizing the results and providing user feedback. To enable communication within the resulting ecology of mobile devices, MobileSSI includes a web socket plugin.\",\n \"Title: Measuring the impact of multimodal behavioural feedback loops on social interactions.\\nYear: 2016\\n\\nAbstract: In this paper we explore the concept of automatic behavioural feedback loops during social interactions. Behavioural feedback loops (BFL) are rapid processes which analyse the behaviour of the user in realtime and provide the user with live feedback on how to improve the behaviour quality. In this context, we implemented an open source software framework for designing, creating and executing BFL on Android powered mobile devices. To get a better understanding of the effects of BFL on face-to-face social interactions, we conducted a user study and compared between four different BFL types spanning three modalities: tactile, auditory and visual. For the study, the BFL have been designed to improve the users' perception of their speaking time in an effort to create more balanced group discussions. The study yielded valuable insights into the impact of BFL on conversations and how humans react to such systems.\",\n \"Title: LeapArm-Facilitating Sensory Spaces for Mid-air Gestural Interaction.\\nYear: 2016\\n\\nAbstract: We present the LeapArm system, which combines a Leap Motion controller for mid-air gestural human-computer interaction with a robotic arm. LeapArm actuates in real-time the orientation of the controller towards a user's hand, dynamically expanding the sensory space for mid-air interaction. We describe several desktop use scenarios and rapid transitions between them, which are enabled by the LeapArm system and discuss how actuated 3D controllers change the design space for gestural interaction.\",\n \"Title: Hold my Heart and Breathe with Me: Tangible Somaesthetic Designs.\\nYear: 2016\\n\\nAbstract: We present two tangible somaesthetic designs. The first design resembles a real heart, which allows users to experience their own heart's behavior by providing haptic feedback. Thus, users holding the heart design are able to feel their heartbeat in their hands. The second design is a stuffed animal, which is capable to breathe in synchrony with a user. Both designs were used as probes in a workshop with two experts practicing and teaching a meditation technique referred to as mindfulness-based stress reduction (MBSR). We conclude that tangible designs may guide users' attention away from themselves towards something outside their bodies (i.e., the artifact). Despite this possibly undesired effect, we argue that there is some potential to exploit tangible designs as mediating tools to address wellbeing for challenging user groups, such as children.\",\n \"Title: Pen + Mid-Air: An Exploration of Mid-Air Gestures to Complement Pen Input on Tablets.\\nYear: 2016\\n\\nAbstract: In this paper, we report on a series of studies, exploring the potential of pen and mid-air input on tablets. We describe a field study with an early prototype of a drawing application and follow-up inquiries, such as the development and comparison of gesture sets for pen and mid-air input and pen and multi-touch input with users in a lab environment. Overall, our results suggest that pen and mid-air input should be offered to complement traditional pen and multi-touch input on tablets. We illustrate the final user-defined gestures set for pen and mid-air input and discuss how user preferences of mid-air gestures over touch gestures seem to depend on the complexity of operations and the need of additional menus on the screen.\",\n \"Title: Towards a Multimedia Knowledge-Based Agent with Social Competence and Human Interaction Capabilities.\\nYear: 2016\\n\\nAbstract: We present work in progress on an intelligent embodied conversation agent in the basic care and healthcare domain. In contrast to most of the existing agents, the presented agent is aimed to have linguistic cultural, social and emotional competence needed to interact with elderly and migrants. It is composed of an ontology-based and reasoning-driven dialogue manager, multimodal communication analysis and generation modules and a search engine for the retrieval of multimedia background content from the web needed for conducting a conversation on a given topic.\",\n \"Title: Touch or Talk?: Comparing Social Robots and Tablet PCs for an Elderly Assistant Recommender System.\\nYear: 2017\\n\\nAbstract: This work is targeted towards the development of a recommender system that fosters the well-being of elderly people in their domestic environment. Since seniors can have a rather high barrier of using newer technologies, the interaction device utilized in such a system has to be selected carefully. This paper compares an anthropomorphic presentation of recommendations by a social robot with a graphical presentation on a tablet PC in terms of the perceived usability, the users' experience and the system's persuasion.\",\n \"Title: Real-Time Robot Personality Adaptation based on Reinforcement Learning and Social Signals.\\nYear: 2017\\n\\nAbstract: Recent findings in Human-Robot Interaction (HRI) indicate that the adaptation of a robot's behaviors to the human's personality profile makes interaction more engaging, but also that it depends on the task context whether a similar or opposing robot personality is preferred. This late breaking report presents our ongoing work on an approach using Reinforcement Learning and social signals for figuring out and adapting to the human preferences, i.e. desired personality profile. Our scenario involves a \\\\\\\"Reeti\\\\\\\" robot in the role of a story teller talking about the main characters in the novel \\\\\\\"Alice's Adventures in Wonderland\\\\\\\" by generating descriptions with varying degree of introversion/extraversion. The learning process is running in real-time during the interaction and allows for simultaneous adaptation without explicitly asking the user about its preferences.\",\n \"Title: Towards a Gamified Recommender System for the Elderly.\\nYear: 2017\\n\\nAbstract: Starting from our previous work on a digital picture frame - the CARE system - that interleaves a picture display mode with a recommender mode to promote a healthy life-style and to increase well-being of elderly people, this paper investigates the use of gamification as a means to increase user appreciation of the CARE system. To this end, we arranged two co-design workshops with peer-groups of senior citizens. We report on outcomes of the workshops and draw conclusions for a gamified version of CARE.\",\n \"Title: Development of a Multi-Device Nutrition Logging Prototype Including a Smartscale.\\nYear: 2017\\n\\nAbstract: In this work we present a portable system for nutrition logging that integrates multiple devices and modalities in order to facilitate food and drink tracking. The system consists of a smartphone, a smartwatch and a smartscale that can be combined flexibly by users depending on the current situation and their personal needs. Based on a requirement analysis, we present the rationale behind the design and implementation of our food and drink logger. We also report the preliminary results of an in-situ study we conducted in order to explore the potential benefits and challenges of a multi-device approach to nutrition tracking in daily life settings.\",\n \"Title: The Senseemotion Database: A Multimodal Database For The Development And Systematic Validation Of An Automatic Pain- And Emotion-Recognition System\\nYear: 2016\\n\\nAbstract: In our modern industrial society the group of the older (generation 65+) is constantly growing. Many subjects of this group are severely affected by their health and are suffering from disability and pain. The problem with chronic illness and pain is that it lowers the patient's quality of life, and therefore accurate pain assessment is needed to facilitate effective pain management and treatment. In the future, automatic pain monitoring may enable health care professionals to assess and manage pain in a more and more objective way. To this end, the goal of our SenseEmotion project is to develop automatic pain- and emotion-recognition systems for successful assessment and effective personalized management of pain, particularly for the generation 65+. In this paper the recently created SenseEmotion Database for pain-vs. emotion-recognition is presented. Data of 45 healthy subjects is collected to this database. For each subject approximately 30 min of multimodal sensory data has been recorded. For a comprehensive understanding of pain and affect three rather different modalities of data are included in this study: biopotentials, camera images of the facial region, and, for the first time, audio signals. Heat stimulation is applied to elicit pain, and affective image stimuli accompanied by sound stimuli are used for the elicitation of emotional states.\",\n \"Title: KRISTINA: A Knowledge-Based Virtual Conversation Agent.\\nYear: 2017\\n\\nAbstract: We present an intelligent embodied conversation agent with linguistic, social and emotional competence. Unlike the vast majority of the state-of-the-art conversation agents, the proposed agent is constructed around an ontology-based knowledge model that allows for flexible reasoning-driven dialogue planning, instead of using predefined dialogue scripts. It is further complemented by multimodal communication analysis and generation modules and a search engine for the retrieval of multimedia background content from the web needed for conducting a conversation on a given topic. The evaluation of the 1st prototype of the agent shows a high degree of acceptance of the agent by the users with respect to its trustworthiness, naturalness, etc. The individual technologies are being further improved in the 2nd prototype.\",\n \"Title: Co-Designing a Recommender System for the Elderly.\\nYear: 2017\\n\\nAbstract: To promote a healthy life-style and to increase well-being of elderly people, we have extended a digital picture frame - the CARE system - that interleaves a picture display mode with a recommender mode. In recommender mode, CARE encourages its users to engage in physical and mental training activities. The success of such a system essentially depends on the extent to which given recommendations are followed. The current paper investigates in how far rewarding schemes as known from computer games could be deployed in order to increase user appreciation of the CARE system. To this end, we prepared and ran a co-design workshop with a peer-group of senior citizens. Finally, we draw conclusions that will guide our work towards a gamified version of CARE.\",\n \"Title: Exploring Opportunistic Ambient Notifications in the Smart Home to Enhance Quality of Live.\\nYear: 2017\\n\\nAbstract: Smart home technology became more and more widespread within recent years. They aim to make life easier and taking over unwanted tasks. In traditional homes, it is often not clear whether all windows and doors of a house are closed before inhabitants leave the home or go to sleep. However, this can be easily addressed by smart homes. We present a system based on opportunistically located ambient lights that assist inhabitants of a smart home in answering this question. In this paper, we show the concept of our system and the inhabitant-centered design process behind the development. The system was installed in a one-family smart home. We report on insights gained through data collected from this deployment over a period of six months. Within interviews, we found that the ambient light system gave inhabitants a more confident feeling about open doors/windows.\",\n \"Title: Temporal Visualization of Energy Consumption Loads Using Time-Tone\\nYear: 2017\\n\\nAbstract: Feedback plays an important role in assisting users to better understand their energy consumption behaviour. This is particularly true when users want to change their behaviour in order to reduce their energy consumption, and to manage their usage more effectively so as to avoid putting unnecessary load on energy providers. This paper presents the time-tone visualization, which aims to assist users by displaying variations in energy consumption by different categories of household devices over time, and their respective contributions to the total energy usage load. A user study conducted to compare time-tone against area-charts shows that although the two visualizations are comparable, time-tone is more effective for cases where there are large variations in energy usage loads.\",\n \"Title: The NoXi database: multimodal recordings of mediated novice-expert interactions.\\nYear: 2017\\n\\nAbstract: We present a novel multi-lingual database of natural dyadic novice-expert interactions, named NoXi, featuring screen-mediated dyadic human interactions in the context of information exchange and retrieval. NoXi is designed to provide spontaneous interactions with emphasis on adaptive behaviors and unexpected situations (e.g. conversational interruptions). A rich set of audio-visual data, as well as continuous and discrete annotations are publicly available through a web interface. Descriptors include low level social signals (e.g. gestures, smiles), functional descriptors (e.g. turn-taking, dialogue acts) and interaction descriptors (e.g. engagement, interest, and fluidity).\",\n \"Title: Pre-touch proxemics: moving the design space of touch targets from still graphics towards proxemic behaviors.\\nYear: 2017\\n\\nAbstract: Proxemic touch targets continuously change in relation to a user's hand in mid-air before a physical touch occurs. Previous work has, for example shown that expanding targets are capable to improve target acquisition performance on touch interfaces. However, it is unclear how proxemic touch targets influence user experience (UX) in a broader sense, including hedonic qualities. Towards closing this research gap the paper reports on two user studies. The first study is a qualitative study with five experts, providing in-depth insights on a variety of change-types (e.g., size, form, color) and how they, for example, influence perceived functional and aesthetic qualities of proxemic touch targets. A follow-up user study with 36 participants explores the UX of a proxemic touch target compared to non-proximal versions of the same target. The results highlight a positive significant effect of the proxemic design on both pragmatic and hedonic qualities.\",\n \"Title: Automatic Detection of Visual Search for the Elderly using Eye and Head Tracking Data.\\nYear: 2017\\n\\nAbstract: With increasing age we often find ourselves in situations where we search for certain items, such as keys or wallets, but cannot remember where we left them before. Since finding these objects usually results in a lengthy and frustrating process, we propose an approach for the automatic detection of visual search for older adults to identify the point in time when the users need assistance. In order to collect the necessary sensor data for the recognition of visual search, we develop a completely mobile eye and head tracking device specifically tailored to the requirements of older adults. Using this device, we conduct a user study with 30 participants aged between 65 and 80 years (\\\\(avg = 71.7,\\\\) 50% female) to collect training and test data. During the study, each participant is asked to perform several activities including the visual search for objects in a real-world setting. We use the recorded data to train a support vector machine (SVM) classifier and achieve a recognition rate of 97.55% with the leave-one-user-out evaluation method. The results indicate the feasibility of an approach towards the automatic detection of visual search in the wild.\",\n \"Title: Adapting a Robot's linguistic style based on socially-aware reinforcement learning\\nYear: 2017\\n\\nAbstract: When looking at Socially Interactive Robots, adaptation to the user's preferences plays an important role in today's Human-Robot Interaction to keep interaction interesting and engaging over a long period of time. Findings indicate an increase in user engagement for robots with adaptive behavior and personality, but also that it depends on the task context whether a similar or opposing robot personality is preferred. We present an approach based on Reinforcement Learning, which gets its reward directly from social signals in real-time during the interaction, to quickly learn about and dynamically address individual human preferences. Our scenario involves a Reeti robot in the role of a story teller talking about the main characters in the novel “Alice's Adventures in Wonderland” by generating descriptions with varying degree of introversion/extraversion. After initial simulation results, an interactive prototype is presented which allows to explore the learning process adapting to the human interaction partner's engagement.\",\n \"Title: Development of a mobile multi-device nutrition logger.\\nYear: 2017\\n\\nAbstract: In this paper we present a mobile system for nutrition logging which integrates multiple devices and modalities to facilitate food and drink tracking. The user is free to decide in each situation to use the most appropriate device combination out of a smartphone, smartwatch and smartscale. We describe the design and implementation of our system which is based on a requirements analysis. Finally, first results of a preliminary in-situ study with the prototype are reported giving first hints about the benefits and challenges of this multi-device approach in daily life scenarios.\",\n \"Title: Applying Cooperative Machine Learning to Speed Up the Annotation of Social Signals in Large Multi-modal Corpora.\\nYear: 2018\\n\\nAbstract: Scientific disciplines, such as Behavioural Psychology, Anthropology and recently Social Signal Processing are concerned with the systematic exploration of human behaviour. A typical work-flow includes the manual annotation (also called coding) of social signals in multi-modal corpora of considerable size. For the involved annotators this defines an exhausting and time-consuming task. In the article at hand we present a novel method and also provide the tools to speed up the coding procedure. To this end, we suggest and evaluate the use of Cooperative Machine Learning (CML) techniques to reduce manual labelling efforts by combining the power of computational capabilities and human intelligence. The proposed CML strategy starts with a small number of labelled instances and concentrates on predicting local parts first. Afterwards, a session-independent classification model is created to finish the remaining parts of the database. Confidence values are computed to guide the manual inspection and correction of the predictions. To bring the proposed approach into application we introduce NOVA - an open-source tool for collaborative and machine-aided annotations. In particular, it gives labellers immediate access to CML strategies and directly provides visual feedback on the results. Our experiments show that the proposed method has the potential to significantly reduce human labelling efforts.\",\n \"Title: Designing Systems to Augment Social Interactions.\\nYear: 2018\\n\\nAbstract: Thanks to the rapid advancement of mobile and wearable technologies over the past decade, a new shift in social skills training lies ahead that will allow users to continuously monitor and improve their social behavior during actual social interactions. At the same time, despite the demonstrated effectiveness of social augmentation, researchers must address several limitations.\",\n \"Title: Simulation Sickness Evaluation While Using A Fully Autonomous Car In A Head Mounted Display Virtual Environment\\nYear: 2018\\n\\nAbstract: Simulation sickness is a condition of physiological discomfort felt during or after exposure to a virtual environment. A virtual environment can be accessed through a head mounted display which provides the user with an entrance to the virtual world. The onset of simulation sickness is a main disadvantage of virtual reality (VR) systems. The proof-of-concept presented in this paper aims to provide new insights into development and evaluation of a VR driving simulation based on consumer electronics devices and a 3 Degrees-of-Freedom (3 DOF) motion platform. A small sample (n = 9) driving simulator pre-study with within-subjects design was conducted to explore simulation sickness outbreak, sense of presence and physiological responses induced by autonomous driving in a dynamic and static driving simulation. The preliminary findings show that users experienced no substantial simulation sickness while using an autonomous car when the VR simulation included a motion platform. This study is the basis for more extensive research in the future. Future studies will include more participants and investigate more factors that contribute to or mitigate the effects of simulation sickness.\",\n \"Title: Marssi: Model Of Appraisal, Regulation, And Social Signal Interpretation\\nYear: 2018\\n\\nAbstract: Understanding emotions of others requires a theory of mind approach providing knowledge of internal appraisal and regulation processes of emotions. Multi-modal social signal classification is insufficient for understanding emotional expressions. Mainly, because many communicative, emotional expressions are not directly related to internal emotional states. Moreover, the recognition of the expression's direction is neglected so far. Even if social signals reveal emotional aspects, the recognition with signal classifiers cannot explain internal appraisal or regulation processes. Using that information is one approach for building cognitive empathic agents with the ability to address observations and motives in an empathic dialogue. In this paper, we introduce a computational model of user emotions for empathic agents. It combines a simulation of appraisal and regulation processes with a social signal interpretation taking directions of expressions into account. Our evaluation shows that social signal sequences can be related to emotion regulation processes. Their recognition and using appraisal and regulation knowledge enables our agent to react empathically.\",\n \"Title: Multiplex Network Structure Enhances The Role Of Generalized Reciprocity In Promoting Cooperation\\nYear: 2018\\n\\nAbstract: In multi-agent systems, cooperative behavior is largely determined by the network structure which dictates the interactions among neighboring agents. These interactions often exhibit multidimensional features, either as relationships of different types or temporal dynamics, both of which may be modeled as a \\\"multiplex\\\" network. Against this background, here we advance the research on cooperation models inspired by generalized reciprocity, a simple pay-it-forward behavioral mechanism, by considering a multidimensional networked society. Our results reveal that a multiplex network structure can act as an enhancer of the role of generalized reciprocity in promoting cooperation by acting as a latent support, even when the parameters in some of the separate network dimensions suggest otherwise (i.e. favor defection). As a result, generalized reciprocity forces the cooperative contributions of the individual agents to concentrate in the dimension which is most favorable for the existence of cooperation.\",\n \"Title: The SSJ Framework: Augmenting Social Interactions Using Mobile Signal Processing and Live Feedback.\\nYear: 2018\\n\\nAbstract: Thanks to recent technological advancements, powerful computers and versatile sensor arrays can now be integrated in small wearable devices. This paper introduces the Android framework SSJ, which makes use of such devices to augment social interaction. To this end, sensor data is first used to analyse the useru0027s behaviour in realtime. Based on the analysis, SSJ then sends live multimodal feedback to the user while they participate in a social interaction. With the help of advanced feedback strategies, SSJ can minimize the disruption of the social interaction while still helping the user improve the quality of their behaviour.\",\n \"Title: EVA: A Multimodal Argumentative Dialogue System.\\nYear: 2018\\n\\nAbstract: This work introduces EVA, a multimodal argumentative Dialogue System that is capable of discussing controversial topics with the user. The interaction is structured as an argument game in which the user and the system select respective moves in order to convince their opponent. EVA's response is presented as a natural language utterance by a virtual agent that supports the respective content using characteristic gestures and mimic.\",\n \"Title: How to Shape the Humor of a Robot - Social Behavior Adaptation Based on Reinforcement Learning.\\nYear: 2018\\n\\nAbstract: A shared sense of humor can result in positive feelings associated with amusement, laughter, and moments of bonding. If robotic companions could acquire their human counterparts' sense of humor in an unobtrusive manner, they could improve their skills of engagement. In order to explore this assumption, we have developed a dynamic user modeling approach based on Reinforcement Learning, which allows a robot to analyze a person's reaction while it tells jokes and continuously adapts its sense of humor. We evaluated our approach in a test scenario with a Reeti robot acting as an entertainer and telling different types of jokes. The exemplary adaptation process is accomplished only by using the audience's vocal laughs and visual smiles, but no other form of explicit feedback. We report on results of a user study with 24 participants, comparing our approach to a baseline condition (with a non-learning version of the robot) and conclude by providing limitations and implications of our approach in detail.\",\n \"Title: Gazeover - Exploring the UX of Gaze-triggered Affordance Communication for GUI Elements.\\nYear: 2018\\n\\nAbstract: The user experience (UX) of graphical user interfaces (GUIs) often depends on how clearly visual designs communicate/signify \\\"affordances\\\", such as if an element on the screen can be pushed, dragged, or rotated. Especially for novice users figuring out the complexity of a new interface can be cumbersome. In the \\\"past\\\" era of mouse-based interaction mouseover effects were successfully utilized to trigger a variety of assistance, and help users in exploring interface elements without causing unintended interactions and associated negative experiences. Today's GUIs are increasingly designed for touch and lack a method similiar to mouseover to help (novice) users to get acquainted with interface elements. In order to address this issue, we have studied gazeover, as a technique for triggering \\\"help or guidance\\\" when a user's gaze is over an interactive element, which we believe is suitable for today's touch interfaces. We report on a user study comparing pragmatic and hedonic qualities of gazeover and mouseover, which showed significant higher ratings in hedonic quality for the gazeover technique. We conclude by discussing limitations and implications of our findings.\",\n \"Title: Pen + Mid-Air Gestures: Eliciting Contextual Gestures.\\nYear: 2018\\n\\nAbstract: Combining mid-air gestures with pen input for bi-manual input on tablets has been reported as an alternative and attractive input technique in drawing applications. Previous work has also argued that mid-air gestural input can cause discomfort and arm fatigue over time, which can be addressed in a desktop setting by allowing users to gesture in alternative restful arm positions (e.g., elbow rests on desk). However, it is unclear if and how gesture preferences and gesture designs would be different for alternative arm positions. In order to inquire these research question we report on a user and choice based gesture elicitation study in which 10 participants designed gestures for different arm positions. We provide an in-depth qualitative analysis and detailed categorization of gestures, discussing commonalities and differences in the gesture sets based on a \\\"think aloud\\\" protocol, video recordings, and self-reports on user preferences.\",\n \"Title: Decision-Theoretic Personality-Based Reasoning About Turn-Taking Conflicts\\nYear: 2018\\n\\nAbstract: This paper outlines the use of an influence diagram for modeling turn-taking timing. In contrast to related works, our model focuses on an agent's personality and attitude towards the conversation partner. We also describe how this model is implemented in a first prototype application.\",\n \"Title: Enabling Privacy With Transfer Learning For Image Classification Dnns On Mobile Devices\\nYear: 2018\\n\\nAbstract: More people could benefit of Machine Learning (ML) as an increasingly important technology and service, if state-of-the-art ML techniques with training capability were accessible on personal devices. To this end, we report details on how to deploy Tensor-Flow on off-the-shelf mobile and embedded devices and retrain current deep neural networks for image recognition on-device. Our motivation is to both grant privacy and allow users to efficiently personalize image classifiers for their own needs and purposes, and thus contribute towards turning ML into a \\\"social good\\\", which benefits the largest number of people in the greatest possible way.\",\n \"Title: PARLEY: a transparent virtual social agent training interface\\nYear: 2019\\n\\nAbstract: In this demo, we present PARLEY, an interactive system to train difficult social situations in a safe environment with a Virtual Agent. The system realizes different phenomena studied by psychology research that are known to create a natural interaction. Moreover, we include an open learner model to ensure an explainable user experience.\",\n \"Title: Emotion recognition using physiological and speech signal in short-term observation\\nYear: 2006\\n\\nAbstract: Recently, there has been a significant amount of work on the recognition of emotions from visual, verbal or physiological information. Most approaches to emotion recognition so far concentrate, however, on a single modality while work on the integration of multimodal information, in particular on fusing physiological signals with verbal or visual data, is scarce. In this paper, we analyze various methods for fusing physiological and vocal information and compare the recognition results of the bimodal recognition approach with the results of the unimodal approach.\",\n \"Title: The Assisted User-Centred Generation and Evaluation of Pervasive Interfaces\\nYear: 2009\\n\\nAbstract: The usability of a pervasive interface is crucial because it is a quality criterion which can determine about the success or the failure of a product. The application of the user-centred design is a possibility to reach a good design. However, this process requires combined knowledge of software and usability engineering. A lack of these skills can cause long development times and additional costs as well as badly usable interfaces. We address these problems and support interface developers with a tool-based assistance which reduces the required programming and interface design skills of the developers in order to more efficiently conduct the user-centred design. In this paper we describe this tool-based assistance for the user-centred generation and evaluation of pervasive interfaces for mobile phones as well as its evaluation.\",\n \"Title: Integrating VR-Authoring and context sensing: towards the creation of context-aware stories\\nYear: 2006\\n\\nAbstract: Recent progress in the area of sensor technology has enabled the development of context-aware systems that are able to dynamically adapt their behaviours to the current situation and the individual user. In this paper, we present a framework for a new generation of context-sensitive stories that dynamically adapt to changing environmental conditions and user states. The framework combines approaches to interactive storytelling with work on context toolkits that foster the rapid prototyping of context-aware applications.\",\n \"Title: What Would You Do in Their Shoes? Experiencing Different Perspectives in an Interactive Drama for Multiple Users\\nYear: 2009\\n\\nAbstract: Following the idea of improvisational theater, we built a multi-agent system where multiple users can experience an interactive drama from different perspectives. Depending on the roles that the users are given in advance, the situation is perceived in various ways and interaction possibilities are directed according to the assigned role. The computer-controlled agents' behavior needs to be highly reactive in order to allow for flexibility in the conversational flow of the structured interactive narrative. In this paper, we describe a system architecture that allows multi-user participation as well as distributed behavior planning for multiple agents.\",\n \"Title: Usage and recognition of finger orientation for multi-touch tabletop interaction\\nYear: 2011\\n\\nAbstract: Building on the observation that finger orientation is an inherent part of human's interaction in the real world, exploiting finger orientation for multitouch tabletop interaction would facilitate more natural interaction techniques. We motivate this by means of examples where the finger orientation improves or enriches interaction. Afterwards, we present a simple and fast approach to detect the finger orientation reliably for multi-touch tabletop interaction. The steps involved are computationally cheap and therefore suit the needs of tracking software operating under time-critical conditions. We show that the presented approach enables the detection of finger orientation also for fingers that touch the tabletop surface only slightly. Further, recognition rates on real data gained from the camera within a multi-touch tabletop are presented in order to give a measure for the precision and reliability of the presented approach.\",\n \"Title: Infected Phonemes: How A Cold Impairs Speech On A Phonetic Level\\nYear: 2017\\n\\nAbstract: The realization of language through vocal sounds involves a complex interplay between the lungs, the vocal cords, and a series of resonant chambers (e.g. mouth and nasal cavities). Due to their connection to the outside world. these body parts are popular spots for viruses and bacteria to enter the human organism. Affected people may suffer from an upper respiratory tract infection (URTIC) and consequently their voice often sounds breathy, raspy or sniffly. In this paper, we investigate the audible effects of a cold on a phonetic level. Results on a German corpus show that the articulation of consonants is more impaired than that of vowels. Surprisingly, nasal sounds do not follow this trend in our experiments. We finally try to predict a speaker's health condition by fusing decisions we derive from single phonemes. The presented work is part of the INTERSPEECH 2017 Computational Paralinguistics Challenge.\",\n \"Title: Of Smarthomes, IoT Plants, and Implicit Interaction Design\\nYear: 2019\\n\\nAbstract: There seems to be a danger to carelessly replace routine tasks in homes through automation with IoT-technology. But since routines, such as watering houseplants also have positive influences on inhabitants' wellbeing, they should be transformed through carefully performed designs. To this end, an attempt to use technology for augmenting a set of houseplants' non-verbal communication capabilities is presented. First, we describe in detail how implicit interactions have been designed to support inhabitants in watering their plants through meaningful interactions. Then, we report on a field study with 24 participants, comparing two alternative design implementations based on contrasting embodied interaction technologies (i.e., augmented reality and embedded computing technology). The study results highlight shortcomings of today's smartphone mediated augmented reality compared to physical interface alternatives, considering measurements of perceived attractiveness and expected effects on determinants of wellbeing, and discusses potentials of combining both modalities for future solutions.\",\n \"Title: Real-Time Adaptation Of A Robotic Joke Teller Based On Human Social Signals\\nYear: 2018\\n\\nAbstract: Humor is an essential element of human-human communication. Consequently, robots in the role of companions should exploit its potential as well to make interactions more enjoyable. Using a robot as an entertainer requires finding out what kind of humor its audience prefers. However, it is a challenging task for a social robot to learn what users prefer without bothering them by repeatedly asking questions. In this paper, we present an approach based on Reinforcement Learning that enables a robot to continuously adapt to the users' humor preferences without requiring them to explicitly provide feedback. Instead, we designed the robot to analyze the user's ideomotor social cues. We evaluated our approach in a scenario involving a Reeti robot acting as an entertainer. In this role, it is telling different types of jokes, (possibly) underlining its performance with grimaces and sounds. The adaptation process is accomplished only by using the audience's vocal laughs and visual smiles, but no other form of explicit feedback.\",\n \"Title: Providing Life-Style-Intervention to Improve Well-Being of Elderly People.\\nYear: 2018\\n\\nAbstract: We report on a user-centered approach towards the development of an augmented digital picture frame - called \\\"CARE\\\" - for senior users with the aim to improve their general well-being. The central idea is to interleave the display of pictures with the provision of recommendations of activities that seniors may perform in addition to their ordinary daily routines. We also report on our attempt to encourage durable use of the CARE system by introducing reward schemes for recommended activities. Feedback from users suggests that reward schemes should be made individually configurable.\",\n \"Title: IEEE Transactions on Affective Computing–Entering the 10th Year of Publication\\nYear: 2019\\n\\nAbstract: AbstractPresents the introductory editorial for this issue of the publication.\",\n \"Title: Insights on usability and user feedback for an assistive robotic health companion with adaptive linguistic style\\nYear: 2019\\n\\nAbstract: Socially assistive robots help the human in everyday tasks. In particular, they can also provide assistance with regard to health and wellbeing, which is an important opportunity to support the independence of the elderly. Since spoken language often carries the essential information, the robot's verbal communication style is of special interest. In order to explore individual user's preferences with regard to the robot's linguistic style we built an autonomous, assistive health companion. It is operated with a custom hardware control panel and offers games, jokes, health-related recommendations, applications for information retrieval and communication. This paper reports on insights from the in-situ user study with regard to the system's usability and participants' feedback.\",\n \"Title: Adaptive linguistic style for an assistive robotic health companion based on explicit human feedback\\nYear: 2019\\n\\nAbstract: In the future, an increasing amount of social robots will be found in our domestic environments to support and facilitate everyday life. Especially in the context of assistive, health-related support, more and more robotic products are on the way to the consumer market. While one can observe that many commercial efforts are put into the visual appearance, embodiment, motion and sound of companion robots, this paper focuses on the robot's conversational skills. We investigate how to adapt the robot's linguistic style to the individual user's preferences. This includes two forms of robot persona in the context of information retrieval tasks and games, as well as politeness with regard to recommendations. Therefore, we present an autonomous companion robot, which adapts its spoken language based on explicit human feedback. It provides several functionalities for information retrieval, reminders, communication and entertainment as well as health-related recommendations. Results of the in-situ study with elderly participants indicate that human preferences vary with regard to the robot's employed politeness strategies. Furthermore, the participants preferred assistant persona over companion persona in the information retrieval context.\",\n \"Title: Stress Annotations from Older Adults - Exploring the Foundations for Mobile ML-Based Health Assistance\\nYear: 2019\\n\\nAbstract: The number of new mobile and wearable technologies with built-in sensors for quantifying every aspect of our lives is increasing. Consequently, new data sources and opportunities arise for the development of machine learning (ML) models and their applications. In this paper, we report on a four weeks field study with 16 older adults, aged between 66 and 81 years (50% female), who were asked to provide stress-related experience samples in different modalities, including paper-based diaries and data collected with the help of a wearable (i.e., a Microsoft Band 2). We provide insights into participants' stress annotation behavior, report on a detailed analysis of the recorded data and the resulting implications regarding the annotation of stressful situations by older adults, discuss how mobile annotation technology can benefit from the synergies with traditional methods and argue why we believe that appropriate annotation techniques are the basis to benefit individually from future powerful machine learning models.\",\n \"Title: Emotion Recognition Based Preference Modelling in Argumentative Dialogue Systems\\nYear: 2019\\n\\nAbstract: Within this work, we present an approach to model the opinion of a human towards a specific topic in a fine-grained way by using weighted bipolar argumentation graphs. In addition, we discuss how the therefore required rating of related aspects can be collected by means of emotion recognition techniques and discuss an application scenario based on the state-of-the-art Argumentative Dialogue System EVA in which the proposed techniques can be applied.\",\n \"Title: Irony Man: Augmenting a Social Robot with the Ability to Use Irony in Multimodal Communication with Humans\\nYear: 2019\\n\\nAbstract: Interpersonal communication is often full of irony and irony related humor, which can shape the quality of a conversation and how conversation partners perceive each other. If social robots were able to integrate irony in their communication style, their human conversation partners might perceive them as more natural, credible, and ultimately more attractive and acceptable. In order to explore this assumption, we first describe an approach to transform non-ironic inputs on-the-fly into multimodal ironic utterances. Irony markers are used to adapt language, prosody and facial expression. We argue that doing this allows to dynamically enrich a robot's spoken language with an expression of socially intelligent behavior. We then demonstrate the feasibility of our approach by reporting on a user study, which compares an ironic version of a robot with a non-ironic version of the same robot in a small talk dialog scenario. Results show that participants are indeed able to correctly identify a robot's use of irony and that a better user experience is associated with an ironic robot version. This is an important step for dynamically shaping a robot's personality and humor, and to increase perceived social intelligence.\",\n \"Title: What If I Speak Now?: A Decision-Theoretic Approach to Personality-Based Turn-Taking\\nYear: 2019\\n\\nAbstract: Embodied conversational agents, which are increasingly prevalent in our society, require turn-taking mechanisms that not only generate fluent conversations but are also consistent with the personality and interpersonal stance required in the given context. We present a decision-theoretic approach for deriving the turn-taking behavior of such an agent from the personality it is meant to convey. For this we gathered relevant theories from psychology and communications research, as well as related systems employing utility-based reasoning. On this basis we describe the construction of an influence diagram which decides between acting and waiting based on those actions' expected utility for the agent's personality-related interaction goals. To test our approach, we integrated our model into an application which simulates conversations between two virtual characters. We then evaluated our prototype by presenting videos of those conversations in an online survey. Our results confirmed that differences in an agent's speaking behavior, generated from different Extraversion configurations in our model, lead to the intended perceptions of its Extraversion, Agreeableness and Status.\",\n \"Title: Designing a Mobile Social and Vocational Reintegration Assistant for Burn-out Outpatient Treatment.\\nYear: 2019\\n\\nAbstract: Using Social Agents as health-care assistants or trainers is one focus area of IVA research. While their use as physical health-care agents is well established, their employment in the field of psychotherapeutic care comes with daunting challenges. This paper presents our mobile Social Agent EmmA in the role of a vocational reintegration assistant for burn-out outpatient treatment. We follow a typical participatory design approach including experts and patients in order to address requirements from both sides. Since the success of such treatments is related to a patients emotion regulation capabilities, we employ a real-time social signal interpretation together with a computational simulation of emotion regulation that influences the agent's social behavior as well as the situational selection of verbal treatment strategies. Overall, our interdisciplinary approach enables a novel integrative concept for Social Agents as assistants for burn-out patients.\",\n \"Title: Teaching Ethics as a Creative Subject: Ideas From an Interdisciplinary Workshop\\nYear: 2021\\n\\nAbstract: Designers and developers have great power and they are often not aware of it. The decisions they make in system design and theway they implement algorithms inevitably encode ethical values. We propose using “Dark Scenarios” as a teaching tool to make ethical issues and value sensitive design a creative process that fits the mindset of designers and developers.\",\n \"Title: Do You Mind if I Pass Through? Studying the Appropriate Robot Behavior when Traversing two Conversing People in a Hallway Setting*\\nYear: 2021\\n\\nAbstract: Several works highlight how robots can navigate in a socially-aware manner by respecting and avoiding people’s personal spaces. But how should the robot act when there is no way around a group of persons? In this work, we explore this question by comparing three different ways to cross two conversing people in a hallway environment. In an online study with 135 participants, users rated the robot’s...\",\n \"Title: A human-driven control architecture for promoting good mental health in collaborative robot scenarios\\nYear: 2021\\n\\nAbstract: This paper introduces the control architecture of a platform aimed at promoting good mental health for workers interacting with collaborative robots (cobots). The platform aim is to render industrial production cells capable of automatically adapting their behavior in order to improve the operator’s quality of experience and level of engagement and to minimize his/her psychological strain. In orde...\",\n \"Title: Dynamic Difficulty Adjustment in Virtual Reality Exergames through Experience-driven Procedural Content Generation.\\nYear: 2021\\n\\nAbstract: Virtual Reality (VR) games that feature physical activities have been shown to increase players' motivation to do physical exercise. However, for such exercises to have a positive healthcare effect, they have to be repeated several times a week. To maintain player motivation over longer periods of time, games often employ Dynamic Difficulty Adjustment (DDA) to adapt the game's challenge according to the player's capabilities. For exercise games, this is mostly done by tuning specific in-game parameters like the speed of objects. In this work, we propose to use experience-driven Procedural Content Generation for DDA in VR exercise games by procedurally generating levels that match the player's current capabilities. Not only finetuning specific parameters but creating completely new levels has the potential to decrease repetition over longer time periods and allows for the simultaneous adaptation of the cognitive and physical challenge of the exergame. As a proof-of-concept, we implement an initial prototype in which the player must traverse a maze that includes several exercise rooms, whereby the generation of the maze is realized by a neural network. Passing those exercise rooms requires the player to perform physical activities. To match the player's capabilities, we use Deep Reinforcement Learning to adjust the structure of the maze and to decide which exercise rooms to include in the maze. We evaluate our prototype in an exploratory user study utilizing both biodata and subjective questionnaires.\",\n \"Title: To Move or Not to Move? Social Acceptability of Robot Proxemics Behavior Depending on User Emotion\\nYear: 2021\\n\\nAbstract: Various works show that proxemics occupies an important role in human-robot interaction and that appropriate proxemic interaction depends on many characteristics of humans and robots. However, there is none that shows the relationship between an emotional state expressed by a user and a proxemic reaction of the robot to it, in a social interaction between these interactants. In the current experiment (N = 82), we investigate this using an online study in which we examine which proxemic response (i.e., approaching, not moving, moving away) to a person's expressed emotional state (i.e., anger, fear, disgust, surprise, sadness, joy) is perceived as appropriate. The quantitative and qualitative data collected suggests that the robot's approach was considered appropriate for the expressed fear, sadness, and joy, whereas moving away was perceived as inappropriate in most scenarios. Further exploratory findings underline the importance of appropriate nonverbal behavior on the perception of the robot.\",\n \"Title: Multi-Modal Pain Intensity Recognition Based on the SenseEmotion Database\\nYear: 2021\\n\\nAbstract: The subjective nature of pain makes it a very challenging phenomenon to assess. Most of the current pain assessment approaches rely on an individual’s ability to recognise and report an observed pain episode. However, pain perception and expression are affected by numerous factors ranging from personality traits to physical and psychological health state. Hence, several approaches have been propos...\",\n \"Title: Socially Interactive Artificial Intelligence: Past, Present and Future\\nYear: 2021\\n\\nAbstract: ABSTRACT Socially interactive artificial agents are no longer mere fiction. For many, they are already part of everyday life. Due to technical advances in multimodal behavior analysis and synthesis, the asymmetry of communication between machines and humans is dissolving. Consequently, the interaction with robots and virtual characters has become more intuitive and natural, particularly for everyday users. Nevertheless, there is still some work to be done until artificial agents are able to smoothly interact with people over more extended periods in their homes and to cope with unforeseen situations. In my talk, I will recall my journey into the field of socially interactive Artificial Intelligence starting in the 90ies with the development of the Personalized Plan-Based Presenter (in short, the PPP Persona [1]). This cartoon character explained technical devices to users by combining speech, gestures, and facial expressions. We quickly realized that we had to equip such characters with a certain amount of social and emotional intelligence to keep users engaged over a more extended period. Furthermore, it became clear that creating such agents is not a job that can be done by computer scientists alone. In collaboration with social and medical sciences, dramaturgy, and media art colleagues, we developed a wide range of applications with socially interactive characters or robots over the past years, including art and entertainment [2], cultural training [5]and social coaching [3], and more recently, personal wellbeing and health [4]. In my talk, I will describe various computational methods to implement socially interactive behaviors in artificial agents. Besides analytic methods informed by theories from the cognitive and social sciences, I will discuss empirical approaches that enable an artificial agent to learn socially interactive behaviors from recordings of human-human interactions or life interactions with human interlocutors. I will highlight opportunities and challenges that arise from neural behavior generation approaches that promise to achieve the next level of human-likeness in virtual agents and social robots. Finally, I will share lessons we learnt during the development of socially interactive agents. To benefit users, we do not just have to work on technical solutions, but go beyond disciplinary boundaries to encompass ethical, legal, and social implications of employing such agents.\",\n \"Title: MultiMediate: Multi-modal Group Behaviour Analysis for Artificial Mediation\\nYear: 2021\\n\\nAbstract: ABSTRACTArtificial mediators are promising to support human group conversations but at present their abilities are limited by insufficient progress in group behaviour analysis. The MultiMediate challenge addresses, for the first time, two fundamental group behaviour analysis tasks in well-defined conditions: eye contact detection and next speaker prediction. For training and evaluation, MultiMediate makes use of the MPIIGroup Interaction dataset consisting of 22 three- to four-person discussions as well as of an unpublished test set of six additional discussions. This paper describes the MultiMediate challenge and presents the challenge dataset including novel fine-grained speaking annotations that were collected for the purpose of MultiMediate. Furthermore, we present baseline approaches and ablation studies for both challenge tasks\",\n \"Title: Social Signals and Multimedia: Past, Present, Future\\nYear: 2021\\n\\nAbstract: ABSTRACTThe rising popularity of Artificial Intelligence (AI) has brought considerable public interest as well faster and more direct transfer of research ideas into practice. One of the aspects of AI that still trails behind considerably is the role of machines in interpreting, enhancing, modeling, generating, and influencing social behavior. Such behavior is captured as social signals, usually by sensors recording multiple modalities, making it classic multimedia data. Such behavior can also be generated by an AI system when interacting with humans. Using AI techniques in combination with multimedia data can be used to pursue multiple goals, two of which are high-lighted here. First, supporting people during social interactions and helping them to fulfil their social needs either actively or passively.Second, improving our understanding of how people collaborate, build relationships, and process self identity. Despite the rise of fields such as Social Signal Processing, a similar panel organised at ACM Multimedia 2014, and an area on social and emotional signal sat the ACM MM since 2014, we argue that we have yet to truly fulfil the potential of the combining social signals and multimedia. This panel asks where we have come far enough and what remaining challenges there are in light of recent global events.\",\n \"Title: Intelligent Signal Processing for Affective Computing [From the Guest Editors]\\nYear: 2021\\n\\nAbstract: Affective computing is computing that relates to, arises from, or deliberately influences emotion or other affective phenomena. Human emotion and affect in general are fundamental to human experience, influencing cognition, perception, and everyday tasks such as learning and communication, but are also fundamental to human health and well-being. The field of affective computing has matured over it...\",\n \"Title: Towards a Deeper Modeling of Emotions: The Deep Method and its Application on Shame\\nYear: 2021\\n\\nAbstract: Understanding emotions is key to Affective Computing. Emotion recognition focuses on the communicative component of emotions encoded in social signals. This view alone is insufficient for deeper understanding and computational representation of the internal, subjectively experienced component of emotions. This paper presents the Deep method as a starting point for a deeper computational modeling o...\",\n \"Title: Implementing Parallel and Independent Movements for a Social Robot's Affective Expressions\\nYear: 2021\\n\\nAbstract: The design and playback of natural and believable movements is a challenge for social robots. They have several limitations due to their physical embodiment, and sometimes also with regard to their software. Taking the example of the expression of happiness, we present an approach for implementing parallel and independent movements for a social robot, which does not have a full-fledged animation A...\",\n \"Title: VoiceMe: Personalized voice generation in TTS\\nYear: 2022\\n\\nAbstract: Novel text-to-speech systems can generate entirely new voices that were not seen during training. However, it remains a difficult task to efficiently create personalized voices from a high-dimensional speaker space. In this work, we use speaker embeddings from a state-of-the-art speaker verification model (SpeakerNet) trained on thousands of speakers to condition a TTS model. We employ a human sampling paradigm to explore this speaker latent space. We show that users can create voices that fit well to photos of faces, art portraits, and cartoons. We recruit online participants to collectively manipulate the voice of a speaking face. We show that (1) a separate group of human raters confirms that the created voices match the faces, (2) speaker gender apparent from the face is well-recovered in the voice, and (3) people are consistently moving towards the real voice prototype for the given face. Our results demonstrate that this technology can be applied in a wide number of applications including character voice development in audiobooks and games, personalized speech assistants, and individual voices for people with speech impairment.\",\n \"Title: GANterfactual - Counterfactual Explanations for Medical Non-experts Using Generative Adversarial Learning.\\nYear: 2022\\n\\nAbstract: With the ongoing rise of machine learning, the need for methods for explaining decisions made by artificial intelligence systems is becoming a more and more important topic. Especially for image classification tasks, many state-of-the-art tools to explain such classifiers rely on visual highlighting of important areas of the input data. Contrary, counterfactual explanation systems try to enable a counterfactual reasoning by modifying the input image in a way such that the classifier would have made a different prediction. By doing so, the users of counterfactual explanation systems are equipped with a completely different kind of explanatory information. However, methods for generating realistic counterfactual explanations for image classifiers are still rare. Especially in medical contexts, where relevant information often consists of textural and structural information, high-quality counterfactual images have the potential to give meaningful insights into decision processes. In this work, we present , an approach to generate such counterfactual image explanations based on adversarial image-to-image translation techniques. Additionally, we conduct a user study to evaluate our approach in an exemplary medical use case. Our results show that, in the chosen medical use-case, counterfactual explanations lead to significantly better results regarding mental models, explanation satisfaction, trust, emotions, and self-efficacy than two state-of-the art systems that work with saliency maps, namely LIME and LRP.\",\n \"Title: Local and Global Explanations of Agent Behavior: Integrating Strategy Summaries with Saliency Maps (Extended Abstract).\\nYear: 2022\\n\\nAbstract: With advances in reinforcement learning (RL), agents are now being developed in high-stakes application domains such as healthcare and transportation. Explaining the behavior of these agents is challenging, as they act in large state spaces, and their decision-making can be affected by delayed rewards. In this paper, we explore a combination of explanations that attempt to convey the global behavior of the agent and local explanations which provide information regarding the agent's decision-making in a particular state. Specifically, we augment strategy summaries that demonstrate the agent's actions in a range of states with saliency maps highlighting the information it attends to. Our user study shows that intelligently choosing what states to include in the summary (global information) results in an improved analysis of the agents. We find mixed results with respect to augmenting summaries with saliency maps (local information).\",\n \"Title: MultiMediate'22: Backchannel Detection and Agreement Estimation in Group Interactions\\nYear: 2022\\n\\nAbstract: ABSTRACTBackchannels, i.e. short interjections of the listener, serve important meta-conversational purposes like signifying attention or indicating agreement. Despite their key role, automatic analysis of backchannels in group interactions has been largely neglected so far. The MultiMediate challenge addresses, for the first time, the tasks of backchannel detection and agreement estimation from backchannels in group conversations. This paper describes the MultiMediate challenge and presents a novel set of annotations consisting of 7234 backchannel instances for the MPIIGroup Interaction dataset. Each backchannel was additionally annotated with the extent by which it expresses agreement towards the current speaker. In addition to a an analysis of the collected annotations, we present baseline results for both challenge tasks.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":200,"string":"200"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13359,"string":"13,359"}}},{"rowIdx":13360,"cells":{"question_id":{"kind":"string","value":"Claude Carlet"},"question":{"kind":"string","value":"Generate an abstract for the title \"A Method of Construction of Balanced Functions with Optimum Algebraic Immunity\" using the following items: 1. Algebraic attacks\n2. Algebraic immunity\n3. Boolean functions\n4. Construction algorithm\n5. Walsh transforms"},"answer":{"kind":"string","value":"Because of the recent algebraic attacks, a high algebraic immunity is now an absolutely necessary (but not sufficient) property for Boolean functions used in stream ciphers. Very few examples of (balanced) functions with high algebraic immunity have been found so far. These examples seem to be isolated and no method for obtaining such functions is known. In this paper, we introduce a general method for proving that a given function, in any number of variables, has a prescribed algebraic immunity. We deduce an algorithm, valid for any even number of variables, for constructing functions with optimum (or, if this can be useful, with high but not optimal) algebraic immunity and which can be balanced if we wish. We also introduce a new example of an infinite class of such functions. We study their Walsh transforms. We finally give similar algorithm and infinite class in the case n is odd (which is different)."},"correct_answer":{"kind":"string","value":"Because of the recent algebraic attacks, a high algebraic immunity is now an absolutely necessary (but not sufficient) property for Boolean functions used in stream ciphers. Very few examples of (balanced) functions with high algebraic immunity have been found so far. These examples seem to be isolated and no method for obtaining such functions is known. In this paper, we introduce a general method for proving that a given function, in any number of variables, has a prescribed algebraic immunity. We deduce an algorithm, valid for any even number of variables, for constructing functions with optimum (or, if this can be useful, with high but not optimal) algebraic immunity and which can be balanced if we wish. We also introduce a new example of an infinite class of such functions. We study their Walsh transforms. We finally give similar algorithm and infinite class in the case n is odd (which is different)."},"documents":{"kind":"list like","value":["Title: Generalized partial spreads\nYear: 1995\n\nAbstract: We exhibit a simple condition under which the sum (modulo 2) of characteristic functions of (n/2)-dimensional vector subspaces of (GF(2))n (n even) is a Bent function. The “Fourier” transform of such a Bent function is the sum of the characteristic functions of the duals of these spaces. The class of Bent functions that we obtain contains the whole partial spreads class. Any element of Maiorana-McFarland's class or of class D is equivalent to one of its elements. Thus this new class gives a unified insight of both general classes of Bent functions studied by Dillon (1974) in his thesis. We deduce a way to construct new classes of Bent functions and exhibit an example","Title: Highly nonlinear mappings\nYear: 2004\n\nAbstract: Functions with high nonlinearity have important applications in cryptography, sequences and coding theory. The purpose of this paper is to give a well-rounded treatment of non-Boolean functions with optimal nonlinearity. We summarize and generalize known results, and prove a number of new results. We also present open problems about functions with high nonlinearity.","Title: Side-channel indistinguishability.\nYear: 2013\n\nAbstract: We introduce a masking strategy for hardware that prevents any side-channel attacker from recovering uniquely the secret key of a cryptographic device. In this masking scheme, termed homomorphic, the sensitive data is exclusive-ored with a random value that belongs to a given set. We show that if this masking set is concealed, then no information about the cryptographic key leaks. If the masking set is public (or disclosed), then any (high-order) attack reveals a group of equiprobable keys. Those results are applied to the case of the AES, where sensitive variables are bytes. To any mask corresponds a masked substitution box. We prove that there exists a homomorphic masking with 16 masks (hence a number of substitution boxes equal to that of the same algorithm without masking) that resists mono-variate first-, second-, and third-order side-channel attacks. Furthermore, even if the masking set is public, each byte of the correct key is found only ex æquo with 15 incorrect ones, making the side-channel analysis insufficient alone -- the remaining key space shall be explored by other means (typically exhaustive search). Thus, our homomorphic masking strategy allows both to increase the number of side-channel measurements and to demand for a final non negligible brute-forcing (of complexity 16NB = 264 for AES, that has NB = 16 substitution boxes). The hardware implementation of the Rotating Substitution boxes Masking (RSM) is a practical instantiation of our homomorphic masking countermeasure.","Title: Partially-Bent Functions\nYear: 1993\n\nAbstract: We study a conjecture stated in [6] about the numbers of non-zeros of, respectively, the auto-correlation function and the Walsh transform of the function (−1)\n f(x), where f(x) is any boolean function on {0, 1}n. The result that we obtain leads us to introduce the class of partially-bent functions. We study within these functions the\n propagation criterion. We characterize those partially-bent functions which are balanced and prove a relation between their\n number (which is unknown) and the number of non-balanced partially-bent functions on {0, 1}\n n−1. Eventually, we study their correlation immunity.","Title: Preface: Volume 6\nYear: 2001\n\nAbstract: The second International Workshop on Coding and Cryptography (WCC 2001) was held in January 8-12, 2001 at the “Cercle National des Armées”, Paris, France. It was jointly organized by INRIA (French National Institute for Research in Computer Science and Control) and the research center of the “Écoles de Coëtquidan”.","Title: On known and new differentially uniform functions\nYear: 2011\n\nAbstract: We give a survey on the constructions of APN and differentially 4-uniform functions suitable for designing S-boxes for block ciphers. We recall why the search for more of such functions is necessary. We propose a way of designing functions which can possibly be APN or differentially 4-uniform and be bijective. We illustrate it with an example of a differentially 4-uniform (n, n)-permutation for n odd, based on the power function x3 over the second order Galois extension of F2n+1, and related to the Dickson polynomial D3 over this field. These permutations have optimal algebraic degree and their nonlinearity happens to be rather good (but worse than that of the multiplicative inverse functions).","Title: On the higher order nonlinearities of algebraic immune functions\nYear: 2006\n\nAbstract: One of the most basic requirements concerning Boolean functions used in cryptosystems is that they must have high algebraic degrees. This simple criterion is not always well adapted to the concrete situation in which Boolean functions are used in symmetric cryptography, since changing one or several output bits of a Boolean function considerably changes its algebraic degree while it may not change its robustness. The proper characteristic is the r-th order nonlinearity profile (which includes the first-order nonlinearity). However, studying it is difficult and almost no paper, in the literature, has ever been able to give general effective results on it. The values of the nonlinearity profile are known for very few functions and these functions have little cryptographic interest. A recent paper has given a lower bound on the nonlinearity profile of functions, given their algebraic immunity. We improve upon it, and we deduce that it is enough, for a Boolean function, to have high algebraic immunity, for having non-weak low order nonlinearity profile (even when it cannot be evaluated), except maybe for the first order.","Title: On Correlation-Immune Functions\nYear: 1991\n\nAbstract: We establish the link between correlation-immune functions and orthogonal arrays. We give a recursive definition of any correlation-immune function of maximal degree. We describe the set of quadratic balanced correlation-immune functions of maximal order. Some constructions are then deduced.","Title: Nonlinearities of S-boxes\nYear: 2007\n\nAbstract: We introduce an indicator of the non-balancedness of functions defined over Abelian groups, and deduce a new indicator, denoted by NB, of the nonlinearity of such functions. We prove an inequality relating NB and the classical indicator NL, introduced by Nyberg and studied by Chabaud and Vaudenay, of the nonlinearity of S-boxes. This inequality results in an upper bound on NL which unifies Sidelnikov-Chabaud-Vaudenay's bound and the covering radius bound. We also deduce from bounds on linear codes three new bounds on NL that improve upon Sidelnikov-Chabaud-Vaudenay's bound and the covering radius bound in many cases.","Title: Self-dual bent functions\nYear: 2010\n\nAbstract: A bent function is called self-dual if it is equal to its dual. It is called anti-self-dual if it is equal to the complement of its dual. A spectral characterisation in terms of the Rayleigh quotient of the Sylvester Hadamard matrix is derived. Bounds on the Rayleigh quotient are given for Boolean functions in an odd number of variables. An efficient search algorithm based on the spectrum of the Sylvester matrix is derived. Primary and secondary constructions are given. All self-dual bent Boolean functions in ≤ 6 variables and all quadratic such functions in eight variables are given, up to a restricted form of affine equivalence.","Title: On Semibent Boolean Functions\nYear: 2012\n\nAbstract: We show that any Boolean function, in even dimension, equal to the sum of a Boolean function $g$ which is constant on each element of a spread and of a Boolean function $h$ whose restrictions to these elements are all linear, is semibent if and only if $g$ and $h$ are both bent. We deduce a large number of infinite classes of semibent functions in explicit bivariate (respectively, univariate) polynomial form.","Title: Algebraic Attacks and Decomposition of Boolean Functions\nYear: 2004\n\nAbstract: Algebraic attacks on LFSR-based stream ciphers recover the secret key by solving an overdefined system of multivariate algebraic equations. They exploit multivariate relations involving key bits and output bits and become very efficient if such relations of low degrees may be found. Low degree relations have been shown to Exist for several well known constructions of stream ciphers immune to all previously known attacks. Such relations may be derived by multiplying the output function of a stream cipher by a well chosen low degree function such that the product function is again of low degree. In view of algebraic attacks, low degree multiples of Boolean functions are a basic concern in the design of stream ciphers as well as of block ciphers. This paper investigates the existence of low degree multiples of Boolean functions in several directions: The known scenarios under which low degree multiples exist are reduced and simplified to two scenarios, that are treated differently in algebraic attacks. A new algorithm is proposed that allows to successfully decide whether a Boolean function has low degree multiples. This represents a significant step towards provable security against algebraic attacks. Furthermore, it is shown that a recently introduced class of degree optimized Maiorana-McFarland functions immanently has low degree multiples. Finally, the probability that a random Boolean function has a low degree multiple is estimated.","Title: On the Propagation Criterion of Degree l and Order k\nYear: 1998\n\nAbstract: We determine those Boolean functions on GF(2)(n) which satisfy the propagation criterion of degree l and order k greater than or equal to n - l - 2. All of theses functions are quadratic. We design nonquadratic Boolean functions satisfying the criterion PC(l) of order k by using the Maiorana-McFarland construction involving nonlinear mappings derived from nonlinear codes.","Title: An Infinite Class of Balanced Functions with Optimal Algebraic Immunity, Good Immunity to Fast Algebraic Attacks and Good Nonlinearity\nYear: 2008\n\nAbstract: After the improvement by Courtois and Meier of the algebraic attacks on stream ciphers and the introduction of the related notion of algebraic immunity, several constructions of infinite classes of Boolean functions with optimum algebraic immunity have been proposed. All of them gave functions whose algebraic degrees are high enough for resisting the Berlekamp-Massey attack and the recent Rønjom-Helleseth attack, but whose nonlinearities either achieve the worst possible value (given by Lobanov's bound) or are slightly superior to it. Hence, these functions do not allow resistance to fast correlation attacks. Moreover, they do not behave well with respect to fast algebraic attacks. In this paper, we study an infinite class of functions which achieve an optimum algebraic immunity. We prove that they have an optimum algebraic degree and a much better nonlinearity than all the previously obtained infinite classes of functions. We check that, at least for small values of the number of variables, the functions of this class have in fact a very good nonlinearity and also a good behavior against fast algebraic attacks.","Title: On the Higher Order Nonlinearities of Boolean Functions and S-Boxes, and Their Generalizations\nYear: 2008\n\nAbstract: The r-th order nonlinearity of a Boolean function $f:F_2^n\\to F_2$ is its minimum Hamming distance to all functions of algebraic degrees at most r, where ris a positive integer. The r-th order nonlinearity of an S-box $F:F_2^n\\to F_2^m$ is the minimum r-th order nonlinearity of its component functions v·F, $v\\in F_2^m\\setminus \\{0\\}$. The role of this cryptographic criterion against attacks on stream and block ciphers has been illustrated by several papers. Its study is also interesting for coding theory and is related to the covering radius of Reed-Muller codes (i.e. the maximum multiplicity of errors that have to be corrected when maximum likelihood decoding is used on a binary symmetric channel). We give a survey of what is known on this parameter, including the bounds involving the algebraic immunity of the function, the bounds involving the higher order nonlinearities of its derivatives, and the resulting bounds on the higher order nonlinearities of the multiplicative inverse functions (used in the S-boxes of the AES). We show an improvement, when we consider an S-box instead of a Boolean function, of the bounds on the higher order nonlinearity expressed by means of the algebraic immunity. We study a generalization (for S-boxes) of the notion and we give new results on it.","Title: On the Higher Order Nonlinearities of Boolean Functions and S-boxes\nYear: 2009\n\nAbstract: This talk will be devoted to symmetric cryptography and more precisely to the Boolean functions it uses for making the systems as nonlinear as possible, allowing them to resist known attacks and hopefully future attacks. These are central objects for the design and the security of symmetric cryptosys- tems (stream ciphers and block ciphers).","Title: On highly nonlinear s-boxes and their inability to thwart DPA attacks\nYear: 2005\n\nAbstract: Prouff has introduced recently, at FSE 2005, the notion of transparency order of S-boxes. This new characteristic is related to the ability of an S-box, used in a cryptosystem in which the round keys are introduced by addition, to thwart single-bit or multi-bit DPA attacks on the system. If this parameter has sufficiently small value, then the S-box is able to withstand DPA attacks without that ad-hoc modifications in the implementation be necessary (these modifications make the encryption about twice slower). We prove a lower bound on the transparency order of highly nonlinear S-boxes. We show that some highly nonlinear functions, and in particular the S-box of AES, have very bad transparency orders.","Title: A New Class of Codes for Boolean Masking of Cryptographic Computations\nYear: 2011\n\nAbstract: We introduce a new class of rate one-half binary codes: complementary information set codes. A binary linear code of length $2n$ and dimension $n$ is called a complementary information set code (CIS code for short) if it has two disjoint information sets. This class of codes contains self-dual codes as a subclass. It is connected to graph correlation immune vectorial Boolean functions of use in the security of hardware implementations of cryptographic primitives. Such codes permit to improve the cost of masking cryptographic algorithms against side channel attacks. In this paper, we investigate this new class of codes: we give optimal or best known CIS codes of length $ < 132$. We derive general constructions based on cyclic codes and on double circulant codes. We derive a Varshamov–Gilbert bound for long CIS codes, and show that they can all be classified in small lengths $\\leq 12$ by the building up construction. Some nonlinear permutations are constructed by using ${\\BBZ}_{4}$-codes, based on the notion of dual distance of a possibly nonlinear code.","Title: A characterization of binary bent functions\nYear: 1996\n\nAbstract: A paper presented by Carlet (see IEEE Transactions on Information Theory, vol.41, p.1482-7, 1995) introduces a general class of binary bent functions whose elements are expressed by means of indicators of n/2-dimensional vector-subspaces of (GF(2))n . An extended version of this class is introduced in the same paper where it is conjectured that this version is equal to the whole class of bent functions. We prove now that this conjecture is true","Title: Secondary Constructions of Bent Functions and Highly Nonlinear Resilient Functions\nYear: 2012\n\nAbstract: In this paper, we first present a new secondary construction of bent functions (building new bent functions from two already defined ones). Furthermore, we apply the construction using as initial functions some specific bent functions and then provide several concrete constructions of bent functions. The second part of the paper is devoted to the constructions of resilient functions. We give a generalization of the indirect sum construction for constructing resilient functions with high nonlinearity. In addition, we modify the generalized construction to ensure a high nonlinearity of the constructed function.","Title: Propagation characteristics and correlation-immunity of highly nonlinear boolean functions\nYear: 2000\n\nAbstract: We investigate the link between the nonlinearity of a Boolean function and its propagation characteristics. We prove that highly nonlinear functions usually have good propagation properties regarding different criteria. Conversely, any Boolean function satisfying the propagation criterion with respect to a linear subspace of codimension 1 or 2 has a high nonlinearity. We also point out that most highly nonlinear functions with a three-valued Walsh spectrum can be transformed into 1-resilient functions.","Title: Hyper-bent functions and cyclic codes\nYear: 2006\n\nAbstract: Bent functions are those Boolean functions whose Hamming distance to the Reed-Muller code of order 1 equal 2n-1) - 2n/2-1 (where the number n of variables is even). These combinatorial objects, with fascinating properties, are rare. Few constructions are known, and it is difficult to know whether the bent functions they produce are peculiar or not, since no way of generating at random bent functions on 8 variables or more is known.The class of bent functions contains a subclass of functions whose properties are still stronger and whose elements are still rarer. Youssef and Gong have proved the existence of such hyperbent functions, for every even n. We prove that the hyper-bent functions they exhibit are exactly those elements of the well-known PIap class, introduced by Dillon, up to the linear transformations x ↦ δx, δ ∈ F2n*. Hyper-bent functions seem still more difficult to generate at random than bent functions; however, by showing that they all can be obtained from some codewords of an extended cyclic code Hn with small dimension, we can enumerate them for up to 10 variables. We study the non-zeroes of Hn and we deduce that the algebraic degree of hyper-bent functions is n/2. We also prove that the functions of class PIap are some codewords of weight 2n-1 - 2n/2-1 of a subcode of Hn and we deduce that for some n, depending on the factorization of 2n - 1, the only hyperbent functions on n variables are the elements of the class PIap#, obtained from PIap by composing the functions by the transformations x ↦ δx, δ ≠ 0, and by adding constant functions. We prove that non-PIap# hyper-bent functions exist for n = 4, but it is not clear whether they exist for greater n. We also construct potentially new bent functions for n = 12.","Title: Codes, Bent Functions and Permutations Suitable For DES-like Cryptosystems\nYear: 1998\n\nAbstract: Almost bent functions oppose an optimum resistance to linear and differential cryptanalysis. We present basic properties of almost bent functions; particularly we give an upper bound on the degree. We develop the \"coding theory\" point of view for studying the existence of almost bent functions, showing explicitly the links with cyclic codes. We also give new characterizations of almost bent functions by means of associated Boolean functions.","Title: Further properties of several classes of Boolean functions with optimum algebraic immunity\nYear: 2007\n\nAbstract: Based on a method proposed by the first author, several classes of balanced Boolean functions with optimum algebraic immunity are constructed, and they have nonlinearities significantly larger than the previously best known nonlinearity of functions with optimal algebraic immunity. By choosing suitable parameters, the constructed n-variable functions have nonlinearity $${2^{n-1}-{n-1\\choose\\frac{n}{2}-1}+2{n-2\\choose\\frac{n}{2}-2}\\Big/(n-2)}$$ for even $${n\\geq 8\\,{\\rm and}\\,2^{n-1}-{n-1\\choose\\frac{n-1}{2}}+\\Delta(n)}$$ for odd n, where Δ(n) is a function increasing rapidly with n. The algebraic degrees of some constructed functions are also discussed.","Title: On the second-order nonlinearities of some bent functions\nYear: 2013\n\nAbstract: The rth-order nonlinearity of Boolean functions plays a central role against several known attacks on stream and block ciphers. It plays also an important role in coding theory, since its maximum equals the covering radius of the rth-order Reed-Muller code. But it is difficult to calculate and even to bound. In this paper, we show lower bounds on the second-order nonlinearity of two subclasses of well-known bent functions. We first improve a known lower bound on the second-order nonlinearity of the simplest partial spread bent functions, whose nonlinearity profile has been bounded by the second author. This improvement allows obtaining a better bound for the whole profile. We subsequently give a lower bound on the second-order nonlinearity of some infinite class of Maiorana-McFarland (M-M) bent functions, which generalizes a result by Gangopadhyay et al.","Title: On bent and highly nonlinear balanced/resilient functions and their algebraic immunities\nYear: 2006\n\nAbstract: Since the introduction of the notions of nonlinearity in the mid-70’s (the term has been in fact introduced later), of correlation immunity and resiliency in the mid-80’s, and of algebraic immunity recently, the problem of efficiently constructing Boolean functions satisfying, at high levels, one or several of these criteria has received much attention. Only few primary constructions are known, and secondary constructions are also necessary to obtain functions achieving or approaching the best possible cryptographic characteristics. After recalling the background on cryptographic criteria and making some general observations, we try to give a survey of all these constructions and their properties. We then show that a nice and simple property of Boolean functions leads to a general secondary construction building an n-variable function from three known n-variable functions. This construction generalizes secondary constructions recently obtained for Boolean bent functions and also leads to secondary constructions of highly nonlinear balanced or resilient functions, with potentially better algebraic immunities than the three functions used as building blocks.","Title: Constructing new APN functions from known ones\nYear: 2007\n\nAbstract: We present a method for constructing new quadratic APN functions from known ones. Applying this method to the Gold power functions we construct an APN function x^3+tr(x^9) over F\"2\"^\"n. It is proven that for n=7 this function is CCZ-inequivalent to the Gold functions, and in the case n=7 it is CCZ-inequivalent to any power mapping (and, therefore, to any APN function belonging to one of the families of APN functions known so far).","Title: Improving the algebraic immunity of resilient and nonlinear functions and constructing bent functions\nYear: 2004\n\nAbstract: The currently known constructions of Boolean functions with high nonlinearities, high algebraic degrees and high resiliency or- ders do not seem to permit achieving suciently high algebraic immunities. We introduce a construction of Boolean functions, which builds a new function from three known ones. Assuming that the three functions have some resiliency order, nonlinearity and algebraic degree, as well as their sum modulo 2, the con- structed function has the same resiliency order and can have the same nonlinearity, but has potentially better algebraic degree and algebraic immunity. The set of classical constructions together with this new one (and with a simpler derived one, having the same advantages) permit now to obtain functions achieving all necessary criteria for being used in the pseudo-random generators in stream ciphers. We also apply this construction to obtain bent functions from known ones.","Title: An Infinite Class of Balanced Vectorial Boolean Functions with Optimum Algebraic Immunity and Good Nonlinearity\nYear: 2009\n\nAbstract: In this paper, we study the cryptographic properties of an infinite class of balanced vectorial Boolean functions recently introduced by Feng, Liao and Yang. These functions provably achieve an optimum algebraic immunity. We give a simpler proof of this fact and we prove that these functions have also an optimum algebraic degree and a non-weak nonlinearity.","Title: Two new classes of bent functions\nYear: 1993\n\nAbstract: We introduce a new class of bent functions on (GF(2))n ( n even). We prove that this class is not included in one of the known classes of bent functions, and that, when n equals 6, it covers the whole set of bent functions of degree 3. This class is obtained by using a result from J.F. Dillon. We generalize this result and deduce a second new class of bent functions which we checked was not included in one of the preceding ones.","Title: An Alternate Characterization of the Bentness of Binary Functions, with Uniqueness\nYear: 1998\n\nAbstract: In a previous paper, we have obtained a characterization of the binary bent functions on (GF(2))n (n even) as linear combinations modulo \n$$2^{\\frac{n}{2}}$$\n, with integral coefficients, of characteristic functions (indicators) of \n$$\\frac{n}{2}$$\n-dimensional vector-subspaces of (GF(2))n. There is no uniqueness of the representation of a given bent function related to this characterization. We obtain now a new characterization for which there is uniqueness of the representation.","Title: Bent functions on a Galois ring and systematic authentication codes.\nYear: 2012\n\nAbstract: A class of bent functions on a Galois ring is introduced and based on these functions systematic authentication codes are presented. These codes generalize those appearing in [4] for finite fields.","Title: More correlation-immune and resilient functions over Galois fields and Galois rings\nYear: 1997\n\nAbstract: We show that the usual constructions of bent functions, when they are suitably modified, allow constructions of correlation-immune and resilient functions over Galois fields and, in some cases, over Galois rings.","Title: Generalized correlation analysis of Vectorial Boolean functions\nYear: 2007\n\nAbstract: We investigate the security of n-bit to m-bit vectorial Boolean functions in stream ciphers. Such stream ciphers have higher throughput than those using single-bit output Boolean functions. However, as shown by Zhang and Chan at Crypto 2000, linear approximations based on composing the vector output with any Boolean functions have higher bias than those based on the usual correlation attack. In this paper, we introduce a new approach for analyzing vector Boolean functions called generalized correlation analysis. It is based on approximate equations which are linear in the input x but of free degree in the output z = F(x). Based on experimental results, we observe that the new generalized correlation attack gives linear approximation with much higher bias than the Zhang-Chan and usual correlation attacks. Thus it can be more effective than previous methods. First, the complexity for computing the generalized nonlinearity for this new attack is reduced from 22m×n+n to 22n. Second, we prove a theoretical upper bound for generalized nonlinearity which is much lower than the unrestricted nonlinearity (for Zhang-Chan's attack) or usual nonlinearity. This again proves that generalized correlation attack performs better than previous correlation attacks. Third, we introduce a generalized divide-and-conquer correlation attack and prove that the usual notion of resiliency is enough to protect against it. Finally, we deduce the generalized nonlinearity of some known secondary constructions for secure vector Boolean functions.","Title: On the construction of bent vectorial functions\nYear: 2010\n\nAbstract: Some properties of power permutations, that is, monomials bijective mappings on double-struck capital F<SUB align=right>2<SUP align=right>n</SUP>, are investigated. In particular, the differential ...","Title: Higher-Order masking schemes for s-boxes\nYear: 2012\n\nAbstract: Masking is a common countermeasure against side-channel attacks. The principle is to randomly split every sensitive intermediate variable occurring in the computation into d+1 shares, where d is called the masking order and plays the role of a security parameter. The main issue while applying masking to protect a block cipher implementation is to design an efficient scheme for the s-box computations. Actually, masking schemes with arbitrary order only exist for Boolean circuits and for the AES s-box. Although any s-box can be represented as a Boolean circuit, applying such a strategy leads to inefficient implementation in software. The design of an efficient and generic higher-order masking scheme was hence until now an open problem. In this paper, we introduce the first masking schemes which can be applied in software to efficiently protect any s-box at any order. We first describe a general masking method and we introduce a new criterion for an s-box that relates to the best efficiency achievable with this method. Then we propose concrete schemes that aim to approach the criterion. Specifically, we give optimal methods for the set of power functions, and we give efficient heuristics for the general case. As an illustration we apply the new schemes to the DES and PRESENT s-boxes and we provide implementation results.","Title: Piecewise Constructions of Bent and Almost Optimal Boolean Functions\nYear: 2005\n\nAbstract: The first aim of this work was to generalize the techniques used in MacWilliams' and Sloane's presentation of the Kerdock code and develop a theory of piecewise quadratic Boolean functions. This generalization led us to construct large families of potentially new bent and almost optimal functions from quadratic forms in this piecewise fashion. We show how our motivating example, the Kerdock code, fits into this setting. These constructions were further generalized to non-quadratic bent functions. The resulting constructions design n-variable bent (resp. almost optimal) functions from n-variable bent or almost optimal functions.","Title: Secondary constructions of bent functions and their enforcement.\nYear: 2012\n\nAbstract: Thirty years ago, Rothaus introduced the notion of bent function and presented a secondary construction (building new bent functions from already defined ones), which is now called the Rothaus construction. This construction has a strict requirement for its initial functions. In this paper, we first concentrate on the design of the initial functions in the Rothaus construction. We show how to construct Maiorana-McFarland's (M-M) bent functions, which can then be used as initial functions, from Boolean permutations and orthomorphic permutations. We deduce that at least (2(n)! x 2(2n))(2(2n) x 2(2n-1))(2) bent functions in 2n + 2 variables can be constructed by using Rothaus' construction. In the second part of the note, we present a new secondary construction of bent functions which generalizes the Rothaus construction. This construction requires initial functions with stronger conditions; we give examples of functions satisfying them. Further, we generalize the new secondary construction of bent functions and illustrate it with examples.","Title: A general case of normal duality between binary nonlinear codes\nYear: 1993\n\nAbstract: We give a general context in which a binary code C admits at least one code whose weight enumerator is dual to that of C. We study two examples of applications of this general result. The first one is the formal duality between the Kerdock and the generalized Preparata codes of same length and the second one gives a new example of dual weight enumerators.","Title: Highly Nonlinear Boolean Functions With Optimal Algebraic Immunity and Good Behavior Against Fast Algebraic Attacks\nYear: 2011\n\nAbstract: Inspired by the previous work of Tu and Deng, we propose two infinite classes of Boolean functions of $2k$ variables where $k\\\\geq 2$. The first class contains unbalanced functions having high algebraic degree and nonlinearity. The functions in the second one are balanced and have maximal algebraic degree and high nonlinearity (as shown by a lower bound that we prove; as a byproduct we also prove a better lower bound on the nonlinearity of the Carlet–Feng function). Thanks to a combinatorial fact, first conjectured by the authors and later proved by Cohen and Flori, we are able to show that they both possess optimal algebraic immunity. It is also checked that, at least for numbers of variables $n\\\\leq 16$, functions in both classes have a good behavior against fast algebraic attacks. Compared with the known Boolean functions resisting algebraic attacks and fast algebraic attacks, both of them possess the highest lower bounds on nonlinearity. These bounds are however not enough for ensuring a sufficient nonlinearity for allowing resistance to fast correlation attack. Nevertheless, as for previously found functions with the same features, there is a gap between the bound that we can prove and the actual values computed for bounded numbers of variables $(n\\\\leq 38)$. Moreover, these values are very good. The infinite class of functions we propose in Construction 2 presents, among all currently known constructions, the best provable tradeoff between all the important cryptographic criteria.","Title: Construction of bent functions via Niho power functions\nYear: 2006\n\nAbstract: A Boolean function with an even number n = 2k of variables is called bent if it is maximally nonlinear. We present here a new construction of bent functions. Boolean functions of the form f(x) = tr(α1xd1 + α2xd2), α1, α2, x ∈ F2n, are considered, where the exponents di (i = 1, 2) are of Niho type, i.e. the restriction of xdi on F2k is linear. We prove for several pairs of (d1, d2) that f is a bent function, when α1 and α2 fulfill certain conditions. To derive these results we develop a new method to prove that certain rational mappings on F2n, are bijective.","Title: Efficient computation of algebraic immunity for algebraic and fast algebraic attacks\nYear: 2006\n\nAbstract: In this paper we propose several efficient algorithms for assessing the resistance of Boolean functions against algebraic and fast algebraic attacks when implemented in LFSR-based stream ciphers. An algorithm is described which permits to compute the algebraic immunity d of a Boolean function with n variables in $\\mathcal{O}(D^2)$ operations, for $D \\approx \\binom{n}{d}$, rather than in $\\mathcal{O}(D^3)$ operations necessary in all previous algorithms. Our algorithm is based on multivariate polynomial interpolation. For assessing the vulnerability of arbitrary Boolean functions with respect to fast algebraic attacks, an efficient generic algorithm is presented that is not based on interpolation. This algorithm is demonstrated to be particularly efficient for symmetric Boolean functions. As an application it is shown that large classes of symmetric functions are very vulnerable to fast algebraic attacks despite their proven resistance against conventional algebraic attacks.","Title: On Almost Perfect Nonlinear Functions\nYear: 2008\n\nAbstract: A function F:F[unk]¿F[unk] is almost perfect nonlinear (APN) if, for every a¿0, b in F[unk], the equation F(x)+ F(x+a)=b has at most two solutions [4]. When used as an S-box in a block cipher, it opposes then an optimum resistance to differential cryptanalysis. The function F is almost bent (AB) if the minimum Hamming distance between all its component functions v·F, v ¿ F[unk]{0}, where \"·\" denotes any inner product in F[unk] and all affine Boolean functions on F[unk] takes the maximal value 2n-1 2(n-1)/2. AB functions exist for n odd only and oppose an optimum resistance to the linear cryptanalysis (see [3]). Every AB function is APN [3], and in the n odd case, any quadratic APN function is AB [2]. The APN and AB properties are preserved by affine equivalence: F~F' if F' = A1[unk] F[unk] A2, where A1, A2 are affine permutations. More generally, they are preserved by CCZ-equivalence [2], that is, affine equivalence of the graphs of F:{(x, F(x)) | x¿F[unk]} and of F'. Until recently, the only known constructions of APN and AB functions were CCZ-equivalent to power functions F(x)=xd over finite fields (F2n being identified with F[unk]).","Title: The complexity of Boolean functions from cryptographic viewpoint\nYear: 2006\n\nAbstract: Cryptographic Boolean functions must be complex to satisfy Shan- non's principle of confusion. But the cryptographic viewpoint on com- plexity is not the same as in circuit complexity. The two main criteria evaluating the cryptographic complexity of Boolean functions on F n 2 are the nonlinearity (and more generally the r-th order nonlinearity, for every positive r < n) and the algebraic degree. Two other criteria have also been considered: the algebraic thickness and the non-normality. After recalling the definitions of these criteria and why, asymptotically, almost all Boolean functions are deeply non-normal and have high algebraic de- grees, high (r-th order) nonlinearities and high algebraic thicknesses, we study the relationship between the r-th order nonlinearity and a recent cryptographic criterion called the algebraic immunity. This relationship strengthens the reasons why the algebraic immunity can be considered as a further cryptographic complexity criterion.","Title: Optimal first-order masking with linear and non-linear bijections\nYear: 2012\n\nAbstract: Hardware devices can be protected against side-channel attacks by introducing one random mask per sensitive variable. The computation throughout is unaltered if the shares (masked variable and mask) are processed concomitantly, in two distinct registers. Nonetheless, this setup can be attacked by a zero-offset second-order CPA attack. The countermeasure can be improved by manipulating the mask through a bijection F, aimed at reducing the dependency between the shares. Thus dth-order zero-offset attacks, that consist in applying CPA on the dth power of the centered side-channel traces, can be thwarted for d≥2 at no extra cost. We denote by n the size in bits of the shares and call F the transformation function, that is a bijection of $\\mathbb{F}_2^n$. In this paper, we explore the functions F that thwart zero-offset HO-CPA of maximal order d. We mathematically demonstrate that optimal choices for F relate to optimal binary codes (in the sense of communication theory). First, we exhibit optimal linear F functions. Second, we note that for values of n for which non-linear codes exist with better parameters than linear ones. These results are exemplified in the case n=8, the optimal F can be identified:it is derived from the optimal rate 1/2 binary code of size 2n, namely the Nordstrom-Robinson (16, 256, 6) code. This example provides explicitly with the optimal protection that limits to one mask of byte-oriented algorithms such as AES or AES-based SHA-3 candidates. It protects against all zero-offset HO-CPA attacks of order d≤5. Eventually, the countermeasure is shown to be resilient to imperfect leakage models.","Title: More Vectorial Boolean Functions With Unbounded Nonlinearity Profile\nYear: 2011\n\nAbstract: The nonlinearity profile of Boolean functions is a generalization of the most important cryptographic criterion, called the (first order) nonlinearity. It is defined as the sequence of the minimum Hamming distances nl(r)(f) between a given Boolean function f and all Boolean functions in the same number of variables and of degrees at most r, for r >= 1. This parameter, which has a close relationship with the Gowers norm, quantifies the resistance to cryptanalyses by low degree approximations of stream ciphers using the Boolean function f as combiner or as filter. The nonlinearity profile can also be defined for vectorial functions: it is the sequence of the minimum Hamming distances between the component functions of the vectorial function and all Boolean functions of degrees at most r, for r >= 1. The nonlinearity profile of the multiplicative inverse functions has been lower bounded in a previous paper by the same author. No other example of an infinite class of functions with unbounded nonlinearity profile has been exhibited since then. In this paper, we lower bound the whole nonlinearity profile of the (simplest) Dillon bent function (x, y) -> xy(2n/2-2), x, y is an element of F-2n/2 and we exhibit another class of functions, for which bounding the whole profile of each of them comes down to bounding the first order nonlinearities of all functions.","Title: Two Classes of Quadratic APN Binomials Inequivalent to Power Functions\nYear: 2008\n\nAbstract: This paper introduces the first found infinite classes of almost perfect nonlinear (APN) polynomials which are not Carlet-Charpin-Zinoviev (CCZ)-equivalent to power functions (at least for some values of the number of variables). These are two classes of APN binomials from F2n to F2n (for n divisible by 3, resp., 4). We prove that these functions are extended affine (EA)-inequivalent to any power function and that they are CCZ-inequivalent to the Gold, Kasami, inverse, and Dobbertin functions when n ges 12. This means that for n even they are CCZ-inequivalent to any known APN function. In particular, for n = 12,20,24, they are therefore CCZ-inequivalent to any power function.","Title: Analysis of the algebraic side channel attack.\nYear: 2012\n\nAbstract: At CHES 2009, Renauld, Standaert and Veyrat-Charvillon introduced a new kind of attack called algebraic side-channel attacks (ASCA). They showed that side-channel information leads to effective algebraic attacks. These results are mostly experiments since strongly based on the use of a SAT solver. This article presents a theoretical study to explain and to characterize the algebraic phase of these attacks. We study more general algebraic attacks based on Gröbner methods. We show that the complexity of the Gröbner basis computations in these attacks depends on a new notion of algebraic immunity defined in this paper, and on the distribution of the leakage information of the cryptosystem. We also study two examples of common leakage models: the Hamming weight and the Hamming distance models. For instance, the study in the case of the Hamming weight model gives that the probability of obtaining at least 64 (resp. 130) linear relations is about 50% for the substitution layer of PRESENT (resp. AES). Moreover if the S-boxes are replaced by functions maximizing the new algebraic immunity criterion then the algebraic attacks (Gröbner and SAT) are intractable. From this theoretical study, we also deduce an invariant which can be easily computed from a given S-box and provides a sufficient condition of weakness under an ASCA. This new invariant does not require any sophisticated algebraic techniques to be defined and computed. Thus, for cryptographic engineers without an advanced knowledge in algebra (e.g. Gröbner basis techniques), this invariant may represent an interesting tool for rejecting weak S-boxes.","Title: On Plateaued Functions and Their Constructions\nYear: 2003\n\nAbstract: We use the notion of covering sequence, introduced by C. Carlet and Y. Tarannikov, to give a simple characterization of bent functions. We extend it into a characterization of plateaued functions (that is bent and three-valued functions). After recalling why the class of plateaued functions provides good candidates to be used in cryptosystems, we study the known families of plateaued functions and their drawbacks. We show in particular that the class given as new by Zhang and Zheng is in fact a subclass of Maiorana-McFarland's class. We introduce a new class of plateaued functions and prove its good cryptographic properties.","Title: Vectorial Functions and Covering Sequences\nYear: 2003\n\nAbstract: The design of large classes of highly nonlinear resilient vectorial functions (mappings from F-2(n) into F-2(m), also called S-boxes) is needed for iterated block ciphers and for pseudo-random generators with multiple output. In this paper, we recall the diverse known constructions of such S-boxes, and we show that those which provide good candidate functions are, in fact, all in the same class. This class corresponds to a generalization of a well known construction due to Maiorana and MacFarland. We study in detail this construction and we specify it to obtain good S-boxes. In a second part, we generalize to S-boxes the notion of covering sequence. We show that this generalization has the same properties as for Boolean functions, and that it has nice additional properties of stability. We study how this notion can be used to design attacks, and we explain why some functions, including the elements of the new class, cannot be involved in the construction of iterated block ciphers.","Title: Differentially 4-Uniform Bijections by Permuting the Inverse Function.\nYear: 2013\n\nAbstract: Block ciphers use substitution boxes (S-boxes) whose aim is to create confusion into the cryptosystems. Functions used as S-boxes should have low differential uniformity, high nonlinearity and algebraic degree larger than 3 (preferably strictly larger). They should be fastly computable; from this viewpoint, it is better when they are in even number of variables. In addition, the functions should be bijections in a substitution-permutation network. Almost perfect nonlinear (APN) functions have the lowest differential uniformity 2 and the existence of APN bijections over for even is a big open problem. In the present paper, we focus on constructing differentially 4-uniform bijections suitable for designing S-boxes for block ciphers. Based on the idea of permuting the inverse function, we design a construction providing a large number of differentially 4-uniform bijections with maximum algebraic degree and high nonlinearity. For every even , we mathematically prove that the functions in a subclass of the constructed class are CCZ-inequivalent to known differentially 4-uniform power functions and to quadratic functions. This is the first mathematical proof that the functions in an infinite class of differentially 4-uniform bijections are CCZ-inequivalent to known differentially 4-uniform power functions and to quadratic functions. We also get a naive lower bound on the nonlinearity of our functions, which can be very high in some cases, and obtain improved lower bounds on the nonlinearity for three special subcases of functions which are extremely large.","Title: CCZ-equivalence of bent vectorial functions and related constructions\nYear: 2011\n\nAbstract: We observe that the CCZ-equivalence of bent vectorial functions over $${{\\bf F}_2^n}$$ (n even) reduces to their EA-equivalence. Then we show that in spite of this fact, CCZ-equivalence can be used for constructing bent functions which are new up to EA-equivalence and therefore to CCZ-equivalence: applying CCZ-equivalence to a non-bent vectorial function F which has some bent components, we get a function F驴 which also has some bent components and whose bent components are CCZ-inequivalent to the components of the original function F. Using this approach we construct classes of nonquadratic bent Boolean and bent vectorial functions.","Title: Concatenating Indicators of Flats for Designing Cryptographic Functions\nYear: 2005\n\nAbstract: Boolean functions with good cryptographic characteristics are needed for the design of robust pseudo-random generators for stream ciphers and of S-boxes for block ciphers. Very few general constructions of such cryptographic Boolean functions are known. The main ones correspond to concatenating affine or quadratic functions. We introduce a general construction corresponding to the concatenation of indicators of flats. We show that the functions it permits to design can present very good cryptographic characteristics.","Title: PICARO: a block cipher allowing efficient higher-order side-channel resistance\nYear: 2012\n\nAbstract: Many papers deal with the problem of constructing an efficient masking scheme for existing block ciphers. We take the reverse approach: that is, given a proven masking scheme (Rivain and Prouff, CHES 2010) we design a block cipher that fits well the masking constraints. The difficulty of implementing efficient masking for a block cipher comes mainly from the S-boxes. Therefore the choice of an adequate S-box is the first and most critical step of our work. The S-box we selected is non-bijective; we discuss the resulting design and security problems. A complete design of the cipher is given, as well as some implementation results.","Title: Relating three nonlinearity parameters of vectorial functions and building APN functions from bent functions\nYear: 2011\n\nAbstract: We survey the properties of two parameters introduced by C. Ding and the author for quantifying the balancedness of vectorial functions and of their derivatives. We give new results on the distribution of the values of the first parameter when applied to F + L, where F is a fixed function and L ranges over the set of linear functions: we show an upper bound on the nonlinearity of F by means of these values, we determine then the mean of these values and we show that their maximum is a nonlinearity parameter as well, we prove that the variance of these values is directly related to the second parameter. We briefly recall the known constructions of bent vectorial functions and introduce two new classes obtained with Gregor Leander. We show that bent functions can be used to build APN functions by concatenating the outputs of a bent (n, n/2)-function and of some other (n, n/2)-function. We obtain this way a general infinite class of quadratic APN functions. We show that this class contains the APN trinomials and hexanomials introduced in 2008 by L. Budaghyan and the author, and a class of APN functions introduced, in 2008 also, by Bracken et al.; this gives an explanation of the APNness of these functions and allows generalizing them. We also obtain this way the recently found Edel---Pott cubic function. We exhibit a large number of other sub-classes of APN functions. We eventually design with this same method classes of quadratic and non-quadratic differentially 4-uniform functions.","Title: A Larger Class of Cryptographic Boolean Functions via a Study of the Maiorana-McFarland Construction\nYear: 2002\n\nAbstract: Thanks to a new upper bound, we study more precisely the nonlinearities of Maiorana-McFarland's resilient functions. We characterize those functions with optimum nonlinearities and we give examples of functions with high nonlinearities. But these functions have a peculiarity which makes them potentially cryptographically weak. We study a natural super-class of Maiorana-McFarland's class whose elements do not have the same drawback and we give examples of such functions achieving high nonlinearities.","Title: An Upper Bound on the Number of m-Resilient Boolean Functions\nYear: 2002\n\nAbstract: The enumeration of m-resilient Boolean functions in n variables would be a quite useful information for cryptography. But it seems to be an intractable open problem. Upper and lower bounds have appeared in the literature in the mid 80驴s. Since then, improving them has been the goal of several papers. In this paper, we give a new upper bound which partially improves upon all the known bounds.","Title: On Dillonʼs class H of bent functions, Niho bent functions and o-polynomials\nYear: 2011\n\nAbstract: One of the classes of bent Boolean functions introduced by John Dillon in his thesis is family H . While this class corresponds to a nice original construction of bent functions in bivariate form, Dillon could exhibit in it only functions which already belonged to the well-known Maiorana–McFarland class. We first notice that H can be extended to a slightly larger class that we denote by H . We observe that the bent functions constructed via Niho power functions, for which four examples are known due to Dobbertin et al. and to Leander and Kholosha, are the univariate form of the functions of class H . Their restrictions to the vector spaces ω F 2 n / 2 , ω ∈ F 2 n ⋆ , are linear. We also characterize the bent functions whose restrictions to the ω F 2 n / 2 ʼs are affine. We answer the open question raised by Dobbertin et al. (2006) in [11] on whether the duals of the Niho bent functions introduced in the paper are affinely equivalent to them, by explicitly calculating the dual of one of these functions. We observe that this Niho function also belongs to the Maiorana–McFarland class, which brings us back to the problem of knowing whether H (or H ) is a subclass of the Maiorana–McFarland completed class. We then show that the condition for a function in bivariate form to belong to class H is equivalent to the fact that a polynomial directly related to its definition is an o-polynomial (also called oval polynomial, a notion from finite geometry). Thanks to the existence in the literature of 8 classes of nonlinear o-polynomials, we deduce a large number of new cases of bent functions in H , which are potentially affinely inequivalent to known bent functions (in particular, to Maiorana–McFarlandʼs functions).","Title: Asymptotic lower bound on the algebraic immunity of random balanced multi-output Boolean functions.\nYear: 2013\n\nAbstract: This paper extends the work of F. Didier (IEEE Transactions on Information Theory, Vol. 52(10): 4496 4503, October 2006) on the algebraic immunity of random balanced Boolean functions, into an asymptotic lower bound on the algebraic immunity of random balanced multi-output Boolean functions.","Title: Achieving side-channel high-order correlation immunity with leakage squeezing.\nYear: 2014\n\nAbstract: This article deeply analyzes high-order (HO) Boolean masking countermeasures against side-channel attacks in contexts where the shares are manipulated simultaneously and the correlation coefficient is used as a statistical distinguisher. The latter attacks are sometimes referred to as zero-offset high-order correlation power analysis (HO-CPA). In particular, the main focus is to get the most out of a single mask (i.e., for masking schemes with two shares). The relationship between the leakage characteristics and the attack efficiency is thoroughly studied. Our main contribution is to link the minimum attack order (called HO-CPA immunity) to the amount of information leaked. Interestingly, the HO-CPA immunity can be much larger than the number of shares in the masking scheme. This is made possible by the leakage squeezing. It is a variant of the Boolean masking where masks are recoded relevantly by bijections. This technique and others from the state-of-the-art (namely leak-free masking and wire-tap codes) are overviewed, and put in perspective.","Title: Constructions of Quadratic and Cubic Rotation Symmetric Bent Functions\nYear: 2012\n\nAbstract: In this paper, we consider constructions of rotation symmetric bent functions, which are of the forms: $f_{c}(x)=\\\\sum _{i=1}^{m-1}c_{i}(\\\\sum _{j=0}^{n-1}x_{j}x_{i+j}) +c_{m}(\\\\sum _{j=0}^{m-1}x_{j}x_{m+j}) $ and $f_{t}(x)=\\\\sum _{i=0}^{n-1}(x_{i}x_{t+i}x_{m+i}+x_{i}x_{t+i}) + \\\\sum _{i=0}^{m-1}x_{i}x_{m+i}$ , where $n=2m$, $ c_{i} \\\\in \\\\{0,1\\\\}$ (the subscript $u$ of $x_{u}$ in the previous expressions is taken as $u$ modulo $n$ ). For each case, a necessary and sufficient condition is obtained. To the best of our knowledge, this class of cubic rotation symmetric bent functions is the first example of an infinite class of nonquadratic rotation symmetric bent functions.","Title: On the confusion and diffusion properties of Maiorana-McFarland's and extended Maiorana-McFarland's functions\nYear: 2004\n\nAbstract: A practical problem in symmetric cryptography is finding constructions of Boolean functions leading to reasonably large sets of functions satisfying some desired cryptographic criteria. The main known construction, called Maiorana-McFarland, has been recently extended. Some other constructions exist, but lead to smaller classes of functions. Here, we study more in detail the nonlinearities and the resiliencies of the functions produced by all these constructions. Further we see how to obtain functions satisfying the propagation criterion (among which bent functions) with these methods, and we give a new construction of bent functions based on the extended Maiorana-McFarland's construction.","Title: Authentication Schemes from Highly Nonlinear Functions\nYear: 2006\n\nAbstract: We construct two families of authentication schemes using highly nonlinear functions on finite fields of characteristic 2. This leads to improvements on an earlier construction by Ding and Niederreiter if one chooses, for instance, an almost bent function as the highly nonlinear function","Title: On the dual of bent functions with 2r Niho exponents\nYear: 2011\n\nAbstract: Computed is the dual of the Niho bent function consisting of 2r exponents that was found by Leander and Kholosha. The algebraic degree of the dual is calculated and it is shown that this new bent function is not of the Niho type. This note is a follow-up of the recent paper by Carlet and Mesnager.","Title: A transformation of boolean functions, its consequences on some problems related to Reed-Muller codes\nYear: 1990\n\nAbstract: We introduce a transformation defined on the set of all boolean functions defined on Galois fields GF(2m), m*,(or on F\n2\nm\n), which changes their weights in a way easy to be followed, and which, when we iterate it, reduces their degrees down to 2 or 3. We deduce that it is as difficult to find a general characterization of the weights in the Reed-Muller codes of order 3 as it is to obtain one in the Reed-Muller codes of any orders. We also use this transformation to characterize the existence of some affine sets of bent functions, and to obtain bent functions of degree 4 from bent functions of degree 3.","Title: The automorphism groups of the Delsarte-Goethals codes\nYear: 1993\n\nAbstract: We determine the automorphism groups of the Delsarte-Goethals codesDG(m, d) (m=2t+2=6, 2=d=t). The groups that we obtain are the same as those of the Kerdock codesK(m) of the same length.","Title: On Cryptographic Propagation Criteria for Boolean Functions\nYear: 1999\n\nAbstract: We determine the functions on GF(2)n which satisfy the propagation criterion of degree n¿2, PC(n¿2). We study subsequently the propagation criterion of degree ¿ and order k and its extended version EPC. We determine those Boolean functions on GF(2)n which satisfy PC(¿) of order k¿n¿¿¿2. We show that none of them satisfies EPC(¿) of the same order. We finally give a general construction of nonquadratic functions satisfying EPC(¿) of order k. This construction uses the existence of nonlinear, systematic codes with good minimum distances and dual distances (e.g., Kerdock codes and Preparata codes).","Title: On a New Notion of Nonlinearity Relevant to Multi-output Pseudo-random Generators\nYear: 2003\n\nAbstract: Vectorial functions (i.e. mappings from F-2(n) into F-2(m), also called S-boxes) can be used in pseudo-random generators with multiple outputs. The notion of maximum correlation of these S-boxes to linear functions, introduced by Zhang and Chan, plays a central role in the resistance of the resulting stream ciphers to correlation attacks. It can be related to a notion of \"unrestricted nonlinearity\". We obtain a new lower bound on the overall maximum correlation to linear functions of vectorial functions which results in an upper bound on the unrestricted nonlinearity. We compare it with the known upper bounds on the nonlinearity (which are also valid for the unrestricted nonlinearity of balanced functions). We study its tightness and we exhibit a class of balanced functions whose nonlinearity and unrestricted nonlinearity are high relatively to the upper-bounds.","Title: Orthogonal Direct Sum Masking A Smartcard Friendly Computation Paradigm In A Code, With Builtin Protection Against Side-Channel And Fault Attacks\nYear: 2014\n\nAbstract: Secure elements, such as smartcards or trusted platform modules (TPMs), must be protected against implementation-level attacks. Those include side-channel and fault injection attacks. We introduce ODSM, Orthogonal Direct Sum Masking, a new computation paradigm that achieves protection against those two kinds of attacks. A large vector space is structured as two supplementary orthogonal subspaces. One subspace (called a code C) is used for the functional computation, while the second subspace carries random numbers. As the random numbers are entangled with the sensitive data, ODSM ensures a protection against (monovariate) side-channel attacks. The random numbers can be checked either occasionally, or globally, thereby ensuring a detection capability. The security level can be formally detailed: it is proved that monovariate side-channel attacks of order up to dC-1, where dC is the minimal distance of C, are impossible, and that any fault of Hamming weight strictly less than dC is detected. A complete instantiation of ODSM is given for AES. In this case, all monovariate side-channel attacks of order strictly less than 5 are impossible, and all fault injections perturbing strictly less than 5 bits are detected.","Title: On the arithmetic Walsh coefficients of Boolean functions\nYear: 2014\n\nAbstract: We generalize to the arithmetic Walsh transform (AWT) some results which were previously known for the Walsh---Hadamard transform of Boolean functions. We first generalize the classical Poisson summation formula to the AWT. We then define a generalized notion of resilience with respect to an arbitrary statistical measure of Boolean functions. We apply the Poisson summation formula to obtain a condition equivalent to resilience for one such statistical measure. Last, we show that the AWT of a large class of Boolean functions can be expressed in terms of the AWT of a Boolean function of algebraic degree at most three in a larger number of variables.","Title: Secondary constructions of highly nonlinear Boolean functions and disjoint spectra plateaued functions\nYear: 2014\n\nAbstract: In this paper, we modify a generalized indirect sum construction to construct functions with high nonlinearity. By utilizing the modified construction, highly nonlinear functions in (n+m) variables can be obtained from known bent functions in n variables and highly nonlinear functions in m variables. It is possible to obtain new (n+15)-variable functions with nonlinearity 2^n^+^1^5^-^1-2^(^n^+^1^5^-^1^)^/^2+20x2^n^/^2 and new 12-variable 2-resilient functions with nonlinearity 2000 and algebraic degree 8, which achieve optimal algebraic immunity. Moreover, the modified construction can also be used as an iterative construction of a quadruple of disjoint spectra plateaued functions. In addition, we present sufficient conditions for a quadruple of disjoint spectra plateaued functions to have no nonzero linear structure.","Title: Quadratic Zero-Difference Balanced Functions, APN Functions and Strongly Regular Graphs.\nYear: 2014\n\nAbstract: Let be a function from to itself and a positive integer. is called zero-difference -balanced if the equation has exactly solutions for all nonzero . As a particular case, all known quadratic planar functions are zero-difference 1-balanced; and some quadratic APN functions over are zero-difference 2-balanced. In this paper, we study the relationship between this notion and differential uniformity; we show that all quadratic zero-difference -balanced functions are differentially -uniform and we investigate in particular such functions with the form , where and where the restriction of to the set of all nonzero th powers in is an injection. We introduce new families of zero-difference -balanced functions. More interestingly, we show that the image set of such functions is a regular partial difference set, and hence yields strongly regular graphs; this generalizes the constructions of strongly regular graphs using planar functions by Weng et al. Using recently discovered quadratic APN functions on , we obtain new negative Latin square type strongly regular graphs.","Title: Higher-Order CIS Codes\nYear: 2014\n\nAbstract: We introduce complementary information set codes of higher order. A binary linear code of length tk and dimension k is called a complementary information set code of order t (t-CIS code for short) if it has t pairwise disjoint information sets. The duals of such codes permit to reduce the cost of masking cryptographic algorithms against side-channel attacks. As in the case of codes for error correction, given the length and the dimension of a t-CIS code, we look for the highest possible minimum distance. In this paper, this new class of codes is investigated. The existence of good long CIS codes of order 3 is derived by a counting argument. General constructions based on cyclic and quasi-cyclic codes and on the building up construction are given. A formula similar to a mass formula is given. A classification of 3-CIS codes of length ≤ 12 is given. Nonlinear codes better than linear codes are derived by taking binary images of Z4-codes. A general algorithm based on Edmonds' basis packing algorithm from matroid theory is developed with the following property: given a binary linear code of rate 1/t, it either provides t disjoint information sets or proves that the code is not t-CIS. Using this algorithm, all optimal or best known [tk, k] codes, where t = 3, 4, . . . , 256 and 1≤ k ≤⌊256/t⌋ are shown to be t-CIS for all such k and t, except for t = 3 with k = 44 and t = 4 with k = 37.","Title: Guest Editorial\nYear: 1999\n\nAbstract: The eight papers in this special section focus on fractional horsepower electric drives. The section covers a wide range of subjects, namely, machine designs, thermal exchange problems, vibration monitoring, and control techniques.","Title: A secondary construction and a transformation on rotation symmetric functions, and their action on bent and semi-bent functions.\nYear: 2014\n\nAbstract: We study more in detail the relationship between rotation symmetric (RS) functions and idempotents, in univariate and bivariate representations, and deduce a construction of bent RS functions from semi-bent RS functions. We deduce the first infinite classes found of idempotent and RS bent functions of algebraic degree more than 3. We introduce a transformation from any RS Boolean function f over GF(2)n into the idempotent Boolean function f′(z)=f(z,z2,…,z2n−1) over GF(2n), leading to another RS Boolean function. The trace representation of f′ is directly deduced from the algebraic normal form of f, but we show that f and f′, which have the same algebraic degree, are in general not affinely equivalent to each other. We exhibit infinite classes of functions f such that (1) f is bent and f′ is not (2) f′ is bent and f is not (3) f and f′ are both bent (we show that this is always the case for quadratic functions and we also investigate cubic functions).","Title: A Class Of 1-Resilient Boolean Functions With Optimal Algebraic Immunity And Good Behavior Against Fast Algebraic Attacks\nYear: 2014\n\nAbstract: Recently, Tang, Carlet and Tang presented a combinatorial conjecture about binary strings, allowing proving that all balanced functions in some infinite class they introduced have optimal algebraic immunity. Later, Cohen and Flori completely proved that the conjecture is true. These functions have good (provable or at least observable) cryptographic properties but they are not 1-resilient, which represents a drawback for their use as filter functions in stream ciphers. We propose a construction of an infinite class of 1-resilient Boolean functions with optimal algebraic immunity by modifying the functions in this class. The constructed functions have optimal algebraic degree, that is, meet the Siegenthaler bound, and high nonlinearity. We prove a lower bound on their non linearity but as for the Carlet-Feng functions and for the functions mentioned above, this bound is not enough for ensuring a nonlinearity sufficient for allowing resistance to the fast correlation attack. Nevertheless, as for previously found functions, With the same features, there is a gap between the bound that We can prove and the actual values computed for small numbers of variables. Our computations show that the functions in this class have very good nonlinearity and also good immunity to fast algebraic attacks. This is the first time that an infinite class of functions gathers all of the main criteria allowing these functions to be used as filters in stream ciphers.","Title: Leakage Squeezing: Optimal Implementation And Security Evaluation\nYear: 2014\n\nAbstract: Hardware devices can be protected against side-channel attacks by introducing one random mask per sensitive variable. The computation throughout is unaltered if the shares (masked variable and mask) are processed concomitantly, in two distinct registers. Nonetheless, this setup can still be attacked if the side-channel is squared, because this operation causes an interference between the two shares. This more sophisticated analysis is referred to as a zero-offset second-order correlation power analysis (CPA) attack. When the device leaks in Hamming distance, the countermeasure can be improved by the \"leakage squeezing\". It consists in manipulating the mask through a bijection, aimed at reducing the dependency between the shares' leakage. Thus dth-order zero-offset attacks, that consist in applying CPA on the dth power of the centered side-channel traces, can be thwarted for d >= 2 at no extra cost. We denote by a the size in bits of the shares and call F the transformation function, that is, a bijection of Viz. In this paper, we explore the functions F that thwart zero-offset high-order CPA (HO-CPA) of maximal order d. We mathematically demonstrate that optimal choices for F relate to optimal binary codes (in the sense of communication theory). First, we exhibit optimal linear F functions. They are suitable for masking schemes where only one mask is used throughout the algorithm. Second, we note that for values of n for which non-linear codes exist with better parameters than linear ones, better protection levels can be obtained. This applies to implementations in which each mask is randomly cast independently of the previous ones. These results are exemplified in the case rz = 8, where the optimal F can be identified: it is derived from the optimal rate 1/2 binary code of size 2n, namely the Nordstrom Robinson (16, 256, 6) code. This example provides explicitly with the optimal protection that limits to one mask of byte-oriented algorithms such as AES or AES-based SHA-3 candidates. It protects against all zero-offset HO-CPA attacks of order d <= 5. Eventually, the countermeasure is shown to be resilient to imperfect leakage models, where the registers leak differently than the sum of their toggling bits.","Title: New Construction Of Differentially 4-Uniform Bijections\nYear: 2013\n\nAbstract: Block ciphers use Substitution boxes (S-boxes) to create confusion into the cryptosystems. For resisting the known attacks on these cryptosystems, the following criteria for functions are mandatory: low differential uniformity, high nonlinearity and not low algebraic degree. Bijectivity is also necessary if the cipher is a Substitution-Permutation Network, and balancedness makes a Feistel cipher lighter. It is well-known that almost perfect nonlinear (APN) functions have the lowest differential uniformity 2 (the values of differential uniformity being always even) and the existence of APN bijections over F(2)n for even n >= 8 is a big open problem. In real practical applications, differentially 4-uniform bijections can be used as S-boxes when the dimension is even. For example, the AES uses a differentially 4-uniform bijection over F(2)8. In this paper, we first propose a method for constructing a large family of differentially 4-uniform bijections in even dimensions. This method can generate at least (2n(-3) - [2((n-1)/2-1)] -1).2(2n-1) such bijections having maximum algebraic degree n-1. Furthermore, we exhibit a subclass of functions having high nonlinearity and being CCZ-inequivalent to all known differentially 4-uniform power bijections and to quadratic functions.","Title: Niho bent functions from quadratic o-monomials\nYear: 2014\n\nAbstract: In this paper, we extend the class of Niho bent function consisting of 2r terms discovered by Leander and Kholosha. The extension is achieved by inserting coefficients of the power terms in the original function. Doing this, we obtain relation to all the existing quadratic o-monomials. We also calculate the algebraic degree of any function in the extended class.","Title: An infinite class of quadratic APN functions which are not equivalent to power mappings\nYear: 2005\n\nAbstract: We exhibit an infinite class of almost perfect nonlinear quadratic polynomials from F2n to F2n (n ≥ 12, n divisible by 3 but not by 9). We prove that these functions are EA-inequivalent to any power function. In the forthcoming version of the present paper we will proof that these functions are CCZ-inequivalent to any Gold function and to any Kasami function, in particular for n = 12, they are therefore CCZ-inequivalent to power functions.","Title: On bent functions associated to AB functions\nYear: 2011\n\nAbstract: In 1998, the second author, Charpin and Zinoviev characterized APN and AB (n, n)-functions by means of associated 2n-variable Boolean functions. In particular, they proved that a function F is AB if and only if the associated Boolean function γF is bent. This observation leads to potentially new bent functions associated to the known AB functions, or at least gives new insight on known bent functions. However, up to now, representations of γF are known only for Gold AB power functions and determining γF for the rest of AB functions is an open problem. In the present paper we determine γF for most of the known families of APN and AB functions.","Title: Generalized bent functions and their relation to Maiorana-McFarland class\nYear: 2012\n\nAbstract: In this paper, most of the known infinite classes of generalized bent functions are analyzed for their relation to the completed Maiorana-McFarland class. This is done using the criterion based on second-order derivatives of a function. In particular, it is shown that, unlike in the binary case, not all quadratic bent functions are EA-equivalent to a function of the Maiorana-McFarland type. This is the first attempt to rise this problem for the generalized bent functions.","Title: On the nonlinearity of monotone Boolean functions.\nYear: 2018\n\nAbstract: We prove a conjecture on the nonlinearity of monotone Boolean functions in even dimension, proposed in the recent paper “Cryptographic properties of monotone Boolean functions”, by Carlet et al. (J. Math. Cryptol. 10(1), 1–14, 2016). We also prove an upper bound on such nonlinearity, which is asymptotically much stronger than the conjectured upper bound and than the upper bound proved for odd dimension in this same paper. Contrary to these two previous bounds, which were not tight enough for allowing to clarify if monotone functions can have good nonlinearity, this new bound shows that the nonlinearity of monotone functions is always very bad, which represents a fatal cryptographic weakness of monotone Boolean functions; they are too closely approximated by affine functions for being usable as nonlinear components in cryptographic applications. We deduce a necessary criterion to be satisfied by a Boolean (resp. vectorial) function for being nonlinear.","Title: Towards Stream Ciphers for Efficient FHE with Low-Noise Ciphertexts.\nYear: 2016\n\nAbstract: Symmetric ciphers purposed for Fully Homomorphic Encryption FHE have recently been proposed for two main reasons. First, minimizing the implementation time and memory overheads that are inherent to current FHE schemes. Second, improving the homomorphic capacity, i.e. the amount of operations that one can perform on homomorphic ciphertexts before bootstrapping, which amounts to limit their level of noise. Existing solutions for this purpose suggest a gap between block ciphers and stream ciphers. The first ones typically allow a constant but small homomorphic capacity, due to the iteration of rounds eventually leading to complex Boolean functions hence large noise. The second ones typically allow a larger homomorphic capacity for the first ciphertext blocks, that decreases with the number of ciphertext blocks due to the increasing Boolean complexity of the stream ciphersu0027 output. In this paper, we aim to combine the best of these two worlds, and propose a new stream cipher construction that allows constant and smaller noise. Its main idea is to apply a Boolean filter function to a public bit permutation of a constant key register, so that the Boolean complexity of the stream cipher outputs is constant. We also propose an instantiation of the filter function designed to exploit recent 3rd-generation FHE schemes, where the error growth is quasi-additive when adequately multiplying ciphertexts with the same amount of noise. In order to stimulate further investigation, we then specify a few instances of this stream cipher, for which we provide a preliminary security analysis. We finally highlight the good properties of our stream cipher regarding the other goal of minimizing the time and memory complexity of calculus delegation for 2nd-generation FHEi¾?schemes. We conclude the paper with open problems related to the large design space opened by these new constructions.","Title: Boolean and Vectorial Plateaued Functions and APN Functions\nYear: 2015\n\nAbstract: Boolean plateaued functions and vectorial functions with plateaued components play a significant role in cryptography, sequences for communications, and the related combinatorics and designs. Our knowledge on them is not at a level corresponding to their importance. We introduce new characterizations of plateaued Boolean functions. We give the characterizations of vectorial functions whose compone...","Title: Complementary dual codes for counter-measures to side-channel attacks.\nYear: 2016\n\nAbstract: We recall why linear codes with complementary duals (LCD codes) play a role in counter-measures to passive and active side-channel analyses on embedded cryptosystems. The rate and the minimum distance of such LCD codes must be as large as possible. We recall the known primary construction of such codes with cyclic codes, and investigate other constructions, with expanded Reed-Solomon codes and generalized residue codes, for which we study the idempotents. These constructions do not allow to reach all the desired parameters. We study then those secondary constructions which preserve the LCD property, and we characterize conditions under which codes obtained by direct sum, direct product, puncturing, shortening, extending codes, or obtained by the Plotkin sum, can be LCD.","Title: A new construction of differentially 4-uniform $(n, n-1)$-functions.\nYear: 2015\n\nAbstract: In this paper, a new way to construct differentially 4-uniform (n, n 1)-functions is presented. As APN (n, n)-functions, these functions offer the best resistance against differential cryptanalysis and they can be used as substitution boxes in block ciphers with a Feistel structure. Constructing such functions is assumed to be as difficult as constructing APN (n, n)-functions. A function in our family of functions can be viewed as the concatenation of two APN (n 1,n 1)-functions satisfying some necessary conditions. Then, we study the special case of this construction in which the two APN functions differ by an affine function. Within this construction, we propose a family in which one of the APN functions is a Gold function which gives the quadratic differentially 4-uniform (n, n 1)-function (x, x(n)) -> x(2i) (+ 1) + x(n)x where x is an element of F-2(n-1) and x(n) is an element of F-2 with gcd (i,n - 1) = 1. We study the nonlinearity of this function in the case i = 1 because in this case we can use results from Carlitz which are unknown in the general case. We also give the Walsh spectrum of this function and prove that it is CCZ-inequivalent to functions of the form L o F where L is an affine surjective (n, n 1)-function and F is a known APN (n, n)-function for n <= 8, or the Inverse APN (n, n)-function for every n >= 5 odd, or any AB (n, n)-function for every n > 3 odd, or any Gold APN (n, n)-function for every n > 4 even.","Title: Univariate Niho Bent Functions From o-Polynomials.\nYear: 2014\n\nAbstract: In this paper, we discover that univariate form of a Niho bent function is a sum of functions having the form of a Leander-Kholosha bent function taken with particular coefficients from F*(2n) for every term. We know that the Niho bent functions are related to o-polynomials. The power terms in the univariate Niho bent function can be derived by working, in a first step, on each monomial of the cor...","Title: S-boxes, Boolean Functions and Codes for the Resistance of Block Ciphers to Cryptographic Attacks, with or without Side Channels.\nYear: 2015\n\nAbstract: The choice of functions $S: \\\\mathbb{F}_2^n\\\\mapsto \\\\mathbb{F}_2^m$ to be used as substitution boxes S-boxes, fastly implementable and contributing to resisting attacks is a crucial question for the design of block ciphers. We summary the state of the art in this domain, considering also the case m<n which has been less studied. We also recall the method for protecting block ciphers against side channel attacks SCA by masking, and how the S-boxes can be processed in order to ensure this protection. We state a related open problem, also interesting for its own sake. We eventually see how Boolean functions, vectorial functions and error correcting codes can be used in different ways for reducing the cost of masking while keeping the same resistance to some SCA and also for allowing resisting fault injection attacks FIA.","Title: Polynomial Evaluation and Side Channel Analysis.\nYear: 2016\n\nAbstract: Side Channel Analysis SCA is a class of attacks that exploits leakage of information from a cryptographic implementation during execution. To thwart it, masking is a common countermeasure. The principle is to randomly split every sensitive intermediate variable occurring in the computation into several shares and the number of shares, called the masking order, plays the role of a security parameter. The main issue while applying masking to protect a block cipher implementation is to specify an efficient scheme to secure the s-box computations. Several masking schemes, applicable for arbitrary orders, have been recently introduced. Most of them follow a similar approach originally introduced in the paper of Carlet et al. published at FSE 2012; the s-box to protect is viewed as a polynomial and strategies are investigated which minimize the number of field multiplications which are not squarings. This paper aims at presenting all these works in a comprehensive way. The methods are discussed, their differences and similarities are identified and the remaining open problems are listed.","Title: On The Properties Of Vectorial Functions With Plateaued Components And Their Consequences On Apn Functions\nYear: 2015\n\nAbstract: [This is an extended abstract of paper [15], which has been submitted to a journal] Boolean plateaued functions and vectorial functions with plateaued components, that we simply call plateaued, play a significant role in cryptography, but little is known on them. We give here, without proofs, new characterizations of plateaued Boolean and vectorial functions, by means of the value distributions of derivatives and of power moments of the Walsh transform. This allows us to derive several characterizations of APN functions in this framework, showing that all the main results known for quadratic APN functions extend to plateaued functions. Moreover, we prove that the APN-ness of those plateaued vectorial functions whose component functions are unbalanced depends only on their value distribution. This proves that any plateaued (n,n)-function, n even, having same value distribution as APN power functions, is APN and has same extended Walsh spectrum as the APN Gold functions.","Title: Evolutionary Approach for Finding Correlation Immune Boolean Functions of Order t with Minimal Hamming Weight.\nYear: 2015\n\nAbstract: The role of Boolean functions is prominent in several areas like cryptography, sequences and coding theory. Therefore, various methods to construct Boolean functions with desired properties are of direct interest. When concentrating on Boolean functions and their role in cryptography, we observe that new motivations and hence new properties have emerged during the years. It is important to note that there are still many design criteria left unexplored and this is where Evolutionary Computation can play a distinct role. One combination of design criteria that has appeared recently is finding Boolean functions that have various orders of correlation immunity and minimal Hamming weight. Surprisingly, most of the more traditionally used methods for Boolean function generation are inadequate in this domain. In this paper, we concentrate on a detailed exploration of several evolutionary algorithms and their applicability for this problem. Our results show that such algorithms are a viable choice when evolving Boolean functions with minimal Hamming weight and certain order of correlation immunity. This approach is also successful in obtaining Boolean functions with several values that were known previously to be theoretically optimal, but no one succeeded in finding actual Boolean functions with such values.","Title: Optimized linear complementary codes implementation for hardware trojan prevention\nYear: 2015\n\nAbstract: Block codes have been shown to be a tool to thwart hardware trojan horses. The state of the electronic circuits is encoded thanks to a pair of complementary codes: one code prevents a purported hardware trojan horses from triggering, while the other one detects any kind of payload. The feasibility and the actual implementation of such defense has be presented thanks to LCD (Linear Complementary Dual) codes and to LCP (Linear Complementary Pair) of codes. In this paper, we optimize the representation of such codes in order to reduce the hardware overhead of the countermeasure.","Title: Algebraic Decomposition for Probing Security.\nYear: 2015\n\nAbstract: The probing security model is very popular to prove the side-channel security of cryptographic implementations protected by masking. A common approach to secure nonlinear functions in this model is to represent them as polynomials over a binary field and to secure their nonlinear multiplications thanks to a method introduced by Ishai, Sahai and Wagner at Crypto 2003. Several schemes based on this approach have been published, leading to the recent proposal of Coron, Roy and Vivek which is currently the best known method when no particular assumption is made on the algebraic structure of the function. In the present paper, we revisit this idea by trading nonlinear multiplications for low-degree functions. Specifically, we introduce an algebraic decomposition approach in which a nonlinear function is represented as a sequence of functions with low algebraic degrees. We therefore focus on the probing-secure evaluation of such low-degree functions and we introduce three novel methods to tackle this particular issue. The paper concludes with a comparative analysis of the proposals, which shows that our algebraic decomposition method outperforms the method of Coron, Roy and Vivek in several realistic contexts.","Title: Cryptographic properties of monotone Boolean functions.\nYear: 2016\n\nAbstract: We prove various results on monotone Boolean functions. In particular, we prove a conjecture proposed recently, stating that there are no monotone bent Boolean functions. Further, we give an upper bound on the nonlinearity of monotone functions in odd dimension, we describe the Walsh-Hadamard spectrum and investigate some other cryptographic properties of monotone Boolean functions.","Title: New secondary constructions of Bent functions.\nYear: 2016\n\nAbstract: In this paper, we first present a novel secondary construction of bent functions (building new bent functions from two already defined ones). Furthermore, the algebraic degree and algebraic immunity of the constructed functions are analysed. Finally, we apply the construction using as initial functions some specific bent functions and then specify sufficient conditions for the resulting bent functions not to be contained in the completed Maiorana---McFarland class. In the second part of the paper, we present a corrigendum of \\\"Constructions of bent---negabent functions and their relation to the completed Maiorana---McFarland Class\\\" (IEEE Trans Inf Theory 61(3):1496---1506, 2015).","Title: Boolean Functions With Restricted Input And Their Robustness; Application To The Flip Cipher\nYear: 2017\n\nAbstract: We study the main cryptographic features of Boolean functions (balanced-ness, nonlinearity, algebraic immunity) when, for a given number n of variables, the input to these functions is restricted to some subset E of F-2(n). We study in particular the case when E equals the set of vectors of fixed Hamming weight, which plays a role in the FLIP stream cipher and we study the robustness of the Boolean function in this cipher.","Title: Evolutionary Algorithms for Boolean Functions in Diverse Domains of Cryptography.\nYear: 2016\n\nAbstract: The role of Boolean functions is prominent in several areas including cryptography, sequences, and coding theory. Therefore, various methods for the construction of Boolean functions with desired properties are of direct interest. New motivations on the role of Boolean functions in cryptography with attendant new properties have emerged over the years. There are still many combinations of design criteria left unexplored and in this matter evolutionary computation can play a distinct role. This article concentrates on two scenarios for the use of Boolean functions in cryptography. The first uses Boolean functions as the source of the nonlinearity in filter and combiner generators. Although relatively well explored using evolutionary algorithms, it still presents an interesting goal in terms of the practical sizes of Boolean functions. The second scenario appeared rather recently where the objective is to find Boolean functions that have various orders of the correlation immunity and minimal Hamming weight. In both these scenarios we see that evolutionary algorithms are able to find high-quality solutions where genetic programming performs the best.","Title: Euclidean and Hermitian LCD MDS codes.\nYear: 2018\n\nAbstract: Linear codes with complementary duals (abbreviated LCD) are linear codes whose intersection with their dual is trivial. When they are binary, they play an important role in armoring implementations against side-channel attacks and fault injection attacks. Non-binary LCD codes in characteristic 2 can be transformed into binary LCD codes by expansion. On the other hand, being optimal codes, maximum distance separable codes (abbreviated MDS) are of much interest from many viewpoints due to their theoretical and practical properties. However, little work has been done on LCD MDS codes. In particular, determining the existence of q-ary [n, k] LCD MDS codes for various lengths n and dimensions k is a basic and interesting problem. In this paper, we firstly study the problem of the existence of q-ary [n, k] LCD MDS codes and solve it for the Euclidean case. More specifically, we show that for \\(q>3\\) there exists a q-ary [n, k] Euclidean LCD MDS code, where \\(0\\le k \\le n\\le q+1\\), or, \\(q=2^{m}\\), \\(n=q+2\\) and \\(k= 3 \\text { or } q-1\\). Secondly, we investigate several constructions of new Euclidean and Hermitian LCD MDS codes. Our main techniques in constructing Euclidean and Hermitian LCD MDS codes use some linear codes with small dimension or codimension, self-orthogonal codes and generalized Reed-Solomon codes.","Title: Componentwise APNness, Walsh uniformity of APN functions and cyclic-additive difference sets.\nYear: 2018\n\nAbstract: In [Characterizations of the differential uniformity of vectorial functions by the Walsh transform, IEEE Transactions on Information Theory 2017], the author has characterized differentially δ-uniform functions by equalities satisfied by their Walsh transforms. This generalizes the characterization of APN functions by the fourth moment of the Walsh transform. We study two notions which are related: (1) the componentwise APNness (CAPNness) of (n,n)-functions, which is a stronger version of APNness, related to the characterization by the fourth moment, in which the arithmetic mean of WF4(u,v) when u ranges over F2n and v is fixed nonzero in F2n equals 22n+1 (2) the componentwise Walsh uniformity (CWU) of (n,m)-functions (m=n, resp. m=n−1), which is a stronger version of APNness (resp. of differential 4-uniformity) related to one of the new characterizations, in which the arithmetic mean of WF2(u1,v1)WF2(u2,v2)WF2(u1+u2,v1+v2) when u1,u2 range independently over F2n and v1,v2 are fixed nonzero and distinct in F2m, equals 23n. Concerning the first notion, it is known from Berger, Canteaut, Charpin and Laigle-Chapuy that any plateaued function is CAPN if and only if it is AB and that APN power permutations are CAPN. We prove that CAPN functions can exist only if n is odd; this solves an eleven year old open problem by these authors. Concerning the second notion, we show that any crooked function (and in particular any quadratic APN function) is CWU, but we observe also that other APN functions like Kasami functions and the inverse of one of the Gold APN permutations are CWU for n≤11. We show that the CWUness of APN power permutations is equivalent to a property of ΔF={F(x)+F(x+1)+1;x∈F2n}. This new property, that we call cyclic-additive difference set property, is more complex than the cyclic difference set property (proved in the case of Kasami APN functions by Dillon and Dobbertin). We prove it in the case of the inverse of Gold function. In the case of Kasami functions, we observe that the cyclic-additive property is also true for n≤10 even and we leave the proof of the CWUness and the cyclic-additive property as open problems.","Title: Linear codes over Fq which are equivalent to LCD codes.\nYear: 2017\n\nAbstract: Linear codes with complementary duals (abbreviated LCD) are linear codes whose intersection with their dual are trivial. When they are binary, they play an important role in armoring implementations against side-channel attacks and fault injection attacks. Non-binary LCD codes in characteristic 2 can be transformed into binary LCD codes by expansion. In this paper, we introduce a general construction of LCD codes from any linear codes. Further, we show that any linear code over $mathbb F_{q} (qu003e3)$ is equivalent to an Euclidean LCD code and any linear code over $mathbb F_{q^2} (qu003e2)$ is equivalent to a Hermitian LCD code. Consequently an $[n,k,d]$-linear Euclidean LCD code over $mathbb F_q$ with $qu003e3$ exists if there is an $[n,k,d]$-linear code over $mathbb F_q$ and an $[n,k,d]$-linear Hermitian LCD code over $mathbb F_{q^2}$ with $qu003e2$ exists if there is an $[n,k,d]$-linear code over $mathbb F_{q^2}$. Hence, when $qu003e3$ (resp.$qu003e2$) $q$-ary Euclidean (resp. $q^2$-ary Hermitian) LCD codes possess the same asymptotical bound as $q$-ary linear codes (resp. $q^2$-ary linear codes). Finally, we present an approach of constructing LCD codes by extending linear codes.","Title: Stochastic Collision Attack.\nYear: 2017\n\nAbstract: On the one hand, collision attacks have been introduced in the context of side-channel analysis for attackers who exploit repeated code with the same data without having any knowledge of the leakage model. On the other hand, stochastic attacks have been introduced to recover leakage models of internally processed intermediate secret variables. Both techniques have shown advantages and intrinsic li...","Title: Trade-Offs for S-Boxes: Cryptographic Properties and Side-Channel Resilience.\nYear: 2017\n\nAbstract: When discussing how to improve side-channel resilience of a cipher, an obvious direction is to use various masking or hiding countermeasures. However, such schemes come with a cost, e.g. an increase in the area and/or reduction of the speed. When considering lightweight cryptography and various constrained environments, the situation becomes even more difficult due to numerous implementation restrictions. However, some options are possible like using S-boxes that are easier to mask or (more on a fundamental level), using S-boxes that possess higher inherent side-channel resilience. In this paper we investigate what properties should an S-box possess in order to be more resilient against side-channel attacks. Moreover, we find certain connections between those properties and cryptographic properties like nonlinearity and differential uniformity. Finally, to strengthen our theoretical findings, we give an extensive experimental validation of our results.","Title: Construction of Highly Nonlinear 1-Resilient Boolean Functions With Optimal Algebraic Immunity and Provably High Fast Algebraic Immunity.\nYear: 2017\n\nAbstract: In 2013, Tang, Carlet, and Tang [IEEE TIT 59(1): 653-664, 2013] presented two classes of Boolean functions. The functions in the first class are unbalanced and the functions in the second one are balanced. Both of those two classes of functions have high nonlinearity, high algebraic degree, optimal algebraic immunity, and high fast algebraic immunity. However, they are not 1-resilient which repres...","Title: New characterization and parametrization of LCD Codes.\nYear: 2019\n\nAbstract: Linear complementary dual (LCD) cyclic codes were referred historically to as reversible cyclic codes, which had applications in data storage. Due to a newly discovered application in cryptography, there has been renewed interest in LCD codes. In particular, it has been shown that binary LCD codes play an important role in implementations against side-channel attacks and fault injection attacks. I...","Title: Characterizations of o-polynomials by the Walsh transform.\nYear: 2017\n\nAbstract: The notion of o-polynomial comes from finite projective geometry. In 2011 and later, it has been shown that those objects play an important role in symmetric cryptography and coding theory to design bent Boolean functions, bent vectorial Boolean functions, semi-bent functions and to construct good linear codes. In this note, we characterize o-polynomials by the Walsh transform of the associated vectorial functions.","Title: A new concatenated type construction for LCD codes and isometry codes.\nYear: 2018\n\nAbstract: We give a new concatenated type construction for linear codes with complementary dual (LCD) over small finite fields. In this construction,we need a special class of inner codes that we call isometry codes. Our construction generalizes a recent construction of Carlet et al. (2014–2016) and of Güneri et al. (2016). In particular, it allows us to construct LCD codes with improved parameters directly.","Title: Classification of Bent Monomials, Constructions of Bent Multinomials and Upper Bounds on the Nonlinearity of Vectorial Functions.\nYear: 2018\n\nAbstract: This paper is composed of two main parts related to the nonlinearity of vectorial functions. The first part is devoted to maximally nonlinear (n, m) functions (the so-called bent vectorial functions), which contribute to an optimal resistance to both linear and differential attacks on symmetric cryptosystems. They can be used in block ciphers at the cost of additional diffusion/compression/expansi...","Title: Three basic questions on Boolean functions.\nYear: 2017\n\nAbstract: In a first part of this paper, we investigate those Boolean functions satisfying two apparently related, but in fact distinct conditions concerning the algebraic degree: 1. we study those Boolean functions f whose restrictions to all affine hyper planes have the same algebraic degree (equal to deg(f), the algebraic degree of f), 2. we study those functions whose derivatives D-a f(x) = f(x) + f(x + a), a not equal 0, have all the same (optimal) algebraic degree deg(f) - 1. For determining to which extent these two questions are related, we find three classes of Boolean functions: the first class satisfies both conditions, the second class satisfies the first condition but not the second and the third class satisfies the second condition but not the first. We also give for any fixed positive integer k and for all integers n, p, s such that p >= k +1, s >= k + 1 and n >= ps, a class (denoted by C-n,C-p,C-s) of functions whose restrictions to all k-codimensional affine subspaces of F-2(n) have the same algebraic degree as the function. In a second part of the paper, we introduce the notion of second-order bent function, whose second order derivatives DaDb f(x) = f (x) + f(x + a) + f(x + b) + f(x + a + b), a not equal 0, b not equal 0, a not equal b, are all balanced. We exhibit an example in 3 variables and we prove that second-order-bent functions cannot exist if n is not congruent with 3 mod 4. We characterize second-order-bent functions by the Walsh transform, state some of their properties and prove the non existence of such functions for algebraic degree 3 when n > 3. We leave open the question whether second-order-bent functions can exist for n larger than 3.","Title: On Upper Bounds for Algebraic Degrees of APN Functions.\nYear: 2018\n\nAbstract: We study the problem of existence of APN functions of algebraic degree n over F2n. We characterize such functions by means of derivatives and power moments of the Walsh transform. We deduce several non-existence results which imply, in particular, that for most of the known APN functions F over F2n. the function x2n-1 + F(x) is not APN, and changing a value of F in a single point then results in n...","Title: Statistical properties of side-channel and fault injection attacks using coding theory.\nYear: 2018\n\nAbstract: Naïve implementation of block ciphers are subject to side-channel and fault injection attacks. To deceive side-channel attacks and to detect fault injection attacks, the designer inserts specially crafted error correcting codes in the implementation. The impact of codes on protection against fault injection attacks is well studied: the number of detected faults relates to their minimum distance. However, regarding side-channel attacks, the link between codes and protection efficiency is blurred. In this paper, we relate statistical properties of code-based countermeasures against side-channel attacks to their efficiency in terms of security, against uni- and multi-variate attacks.","Title: Polynomial direct sum masking to protect against both SCA and FIA.\nYear: 2018\n\nAbstract: Side-channel attacks (SCAs) and fault injection attacks (FIAs) allow an opponent to have partial access to the internal behavior of the hardware. Since the end of the 1990s, many works have shown that this type of attacks constitutes a serious threat to cryptosystems implemented in embedded devices. In the state of the art, there exist several countermeasures to protect symmetric encryption (especially AES-128). Most of them protect only against one of these two attacks (SCA or FIA). A method called ODSM has been proposed to withstand SCA and FIA, but its implementation in the whole algorithm is a big open problem when no particular hardware protection is possible. In the present paper, we propose a practical masking scheme specifying ODSM which makes it possible to protect the symmetric encryption against these two attacks.","Title: Problems and solutions of the Fourth International Students' Olympiad in Cryptography NSUCRYPTO.\nYear: 2018\n\nAbstract: Mathematical problems and their solutions from the fourth International Students' Olympiad in cryptography (NSUCRYPTO-2017) are presented. We consider problems related to attacks on ciphers and hash functions, cryptographic Boolean functions, linear branch numbers, addition chains, and error correction codes, among others. We discuss several open problems involving the algebraic structures of cryptographic functions, useful proof-of-work algorithms, the Boolean hidden shift problem, and quantum computing.","Title: Two constructions of optimal pairs of linear codes for resisting side channel and fault injection attacks.\nYear: 2018\n\nAbstract: Direct sum masking (DSM) has been proposed as a counter-measure against side-channel attacks (SCA) and fault injection attacks (FIA), which are nowadays important domains of cryptanalysis. DSM needs two linear codes whose sum is direct and equals a whole space $Bbb F_q^n$. The minimum distance of the former code and the dual distance of the latter should be as large as possible, given their length and dimensions. But the implementation needs in practice to work with words obtained by appending, to each codeword $y$ of the latter code, the source word from which $y$ is the encoding. Let $mathcal C_1$ be an $[n, k]$ linear code over the finite field $Bbb F_q$ with generator matrix $G$ and let $mathcal C_2$ be the linear code over the finite field $Bbb F_q$ with generator matrix $[G, I_k]$. It is then highly desired to construct optimal pairs of linear codes satisfying that $d(mathcal C_2^perp)= d(mathcal C_1^perp)$. In this paper, we employ the primitive irreducible cyclic codes to derive two constructions of optimal pairs of linear codes for resisting SCA and FIA, where the security parameters are determined explicitly. To the best of our knowledge, it is the first time that primitive irreducible cyclic codes are used to construct (optimal) pairs of codes. As a byproduct, we obtain the weight enumerators of the codes $mathcal C_1, mathcal C_2, mathcal C_1^perp$, and $mathcal C_2^perp$ in our both constructions.","Title: On Linear Complementary Pairs of Codes.\nYear: 2018\n\nAbstract: We study linear complementary pairs (LCP) of codes (C, D), where both codes belong to the same algebraic code family. We especially investigate constacyclic and quasicyclic LCP of codes. We obtain characterizations for LCP of constacyclic codes and LCP of quasi-cyclic codes. Our result for the constacyclic complementary pairs extends the characterization of linear complementary dual (LCD) cyclic c...","Title: Constructing APN Functions Through Isotopic Shifts\nYear: 2018\n\nAbstract: Almost perfect nonlinear (APN) functions over fields of characteristic 2 play an important role in cryptography, coding theory and, more generally, mathematics and information theory. In this paper we deduce a new method for constructing APN functions by studying the isotopic equivalence, concept defined for quadratic planar functions in fields of odd characteristic. In particular, we construct a family of quadratic APN functions which provides a new example of an APN mapping over F\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">29</sub>\n and includes an example of another APN function x\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">9</sup>\n + Tr(x\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n) over F\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">28</sub>\n, known since 2006 and not classified up to now. We conjecture that the conditions for this family are satisfied by infinitely many APN functions.","Title: Construction of Some Codes Suitable for Both Side Channel and Fault Injection Attacks.\nYear: 2018\n\nAbstract: Using algebraic curves over finite fields, we construct some codes suitable for being used in the countermeasure called Direct Sum Masking which allows, when properly implemented, to protect the whole cryptographic block cipher algorithm against side channel attacks and fault injection attacks, simultaneously. These codes address a problem which has its own interest in coding theory.","Title: On <inline-formula> <tex-math notation=\"LaTeX\">$\\sigma$ </tex-math></inline-formula>-LCD Codes\nYear: 2019\n\nAbstract: Linear complementary pairs (LCPs) of codes play an important role in armoring implementations against side-channel attacks and fault injection attacks. One of the most common ways to construct LCP of codes is to use Euclidean linear complementary dual (LCD) codes. In this paper, we first introduce the concept of linear codes with \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n complementary dual (\n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD), which includes known Euclidean LCD codes, Hermitian LCD codes, and Galois LCD codes. Like Euclidean LCD codes, \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD codes can also be used to construct LCP of codes. We show that for \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$q > 2$ </tex-math></inline-formula>\n, all \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$q$ </tex-math></inline-formula>\n-ary linear codes are \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD, and for every binary linear code \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\mathcal C$ </tex-math></inline-formula>\n, the code \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\{0\\}\\times \\mathcal C$ </tex-math></inline-formula>\n is \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD. Furthermore, we study deeply \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD generalized quasi-cyclic (GQC) codes. In particular, we provide the characterizations of \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD GQC codes, self-orthogonal GQC codes, and self-dual GQC codes, respectively. Moreover, we provide the constructions of asymptotically good \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD GQC codes. Finally, we focus on \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD abelian codes and prove that all abelian codes in a semi-simple group algebra are \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD. The results derived in this paper extend those on the classical LCD codes and show that \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\sigma $ </tex-math></inline-formula>\n-LCD codes allow the construction of LCP of codes more easily and with more flexibility.","Title: On APN exponents, characterizations of differentially uniform functions by the Walsh transform, and related cyclic-difference-set-like structures.\nYear: 2019\n\nAbstract: In this paper, we summarize the results obtained recently in three papers on differentially uniform functions in characteristic 2, and presented at the workshop WCC 2017 in Saint-Petersburg, and we give new results on these functions. Firstly, we recall the recent connection between almost perfect nonlinear (APN) power functions and the two notions in additive combinatorics of Sidon sets and sum-free sets; we also recall a characterization of APN exponents which leads to a property of Dickson polynomials in characteristic 2 previously unobserved, which is generalizable to all finite fields. We also give a new characterization of APN exponents in odd dimension by Singer sets. Secondly, after recalling the recent multiple generalization to differentially \\(\\delta \\)-uniform functions of the Chabaud–Vaudenay characterization of APN functions by their Walsh transforms, we generalize the method to all criteria on vectorial functions dealing with the numbers of solutions of equations of the form \\(\\sum _{i\\in I}F(x+u_{i,a})+L_a(x)+u_a=0\\), with \\(L_a\\) linear; we give the examples of injective functions and of o-polynomials; we also deduce a generalization to differentially \\(\\delta \\)-uniform functions of the Nyberg characterization of APN functions by means of the Walsh transforms of their derivatives. Thirdly, we recall the two notions of componentwise APNness (CAPNness) and componentwise Walsh uniformity (CWU). We recall why CAPN functions can exist only if n is odd and why crooked functions (in particular, quadratic APN functions) are CWU. We also recall that the inverse of one of the Gold permutations is CWU and not the others. Another potential class of CWU functions is that of Kasami functions. We consider the difference sets with Singer parameters equal to the complement of \\(\\varDelta _F=\\{F(x)+F(x+1)+1; x\\in \\mathbb {F}_{2^n}\\}\\) where F is a Kasami function. These sets have another potential property, called the cyclic-additive difference set property, which is related to the CWU property in the case of power permutations (n odd). We study cyclic-additive difference sets among Singer sets. We recall the main properties of Kasami functions and of the related set \\(\\varDelta _F\\) shown by Dillon and Dobbertin and we observe and prove new expressions for \\(\\varDelta _F\\).","Title: A New Representation of Boolean Functions\nYear: 1999\n\nAbstract: We study a representation of Boolean functions (and more generally of integer-valued / complex-valued functions), not used until now in coding and cryptography, which yields more information than the currently known representations, on the combinatorial, spectral and cryptographic properties of the functions.","Title: On immunity profile of boolean functions\nYear: 2006\n\nAbstract: The notion of resilient function has been recently weakened to match more properly the features required for Boolean functions used in stream ciphers. We introduce and we study an alternate notion of almost resilient function. We show that it corresponds more closely to the requirements that make the cipher more resistant to precise attacks.","Title: Binary Linear Codes From Vectorial Boolean Functions and Their Weight Distribution.\nYear: 2017\n\nAbstract: Binary linear codes with good parameters have important applications in secret sharing schemes, authentication codes, association schemes, and consumer electronics and communications. In this paper, we construct several classes of binary linear codes from vectorial Boolean functions and determine their parameters, by further studying a generic construction developed by Ding et al. recently. First, by employing perfect nonlinear functions and almost bent functions, we obtain several classes of six-weight linear codes which contain the all-one codeword, and determine their weight distribution. Second, we investigate a subcode of any linear code mentioned above and consider its parameters. When the vectorial Boolean function is a perfect nonlinear function or a Gold function in odd dimension, we can completely determine the weight distribution of this subcode. Besides, our linear codes have larger dimensions than the ones by Ding et al.’s generic construction.","Title: Characterizations of the differential uniformity of vectorial functions by the Walsh transform.\nYear: 2018\n\nAbstract: For every positive integers n and m and every even positive integer δ, we derive inequalities satisfied by the Walsh transforms of all vectorial (n, m)-functions and prove that the case of equality characterizes differential δ-uniformity. This provides a generalization to all differentially δ-uniform functions of the characterization of Almost Perfect Nonlinear (APN) functions due to Chabaud and V...","Title: Connecting and Improving Direct Sum Masking and Inner Product Masking.\nYear: 2017\n\nAbstract: Direct Sum Masking (DSM) and Inner Product (IP) masking are two types of countermeasures that have been introduced as alternatives to simpler (e.g., additive) masking schemes to protect cryptographic implementations against side-channel analysis. In this paper, we first show that IP masking can be written as a particular case of DSM. We then analyze the improved security properties that these (more complex) encodings can provide over Boolean masking. For this purpose, we introduce a slight variation of the probing model, which allows us to provide a simple explanation to the “security order amplification” for such masking schemes that was put forward at CARDIS 2016. We then use our model to search for new instances of masking schemes that optimize this security order amplification. We finally discuss the relevance of this security order amplification (and its underlying assumption of linear leakages) based on an experimental case study.","Title: On the Derivative Imbalance and Ambiguity of Functions.\nYear: 2019\n\nAbstract: In 2007, Carlet and Ding introduced two parameters, denoted by $Nb_F$ and $NB_F$, quantifying respectively the balancedness of general functions $F$ between finite Abelian groups and the (global) balancedness of their derivatives $D_a F(x)=F(x+a)-F(x)$, $ain Gsetminus{0}$ (providing an indicator of the nonlinearity of the functions). These authors studied the properties and cryptographic significance of these two measures. They provided for S-boxes inequalities relating the nonlinearity $mathcal{NL}(F)$ to $NB_F$, and obtained in particular an upper bound on the nonlinearity which unifies Sidelnikov-Chabaud-Vaudenayu0027s bound and the covering radius bound. At the Workshop WCC 2009 and in its postproceedings in 2011, a further study of these parameters was made; in particular, the first parameter was applied to the functions $F+L$ where $L$ is affine, providing more nonlinearity parameters. In 2010, motivated by the study of Costas arrays, two parameters called ambiguity and deficiency were introduced by Panario emph{et al.} for permutations over finite Abelian groups to measure the injectivity and surjectivity of the derivatives respectively. These authors also studied some fundamental properties and cryptographic significance of these two measures. Further studies followed without that the second pair of parameters be compared to the first one. In the present paper, we observe that ambiguity is the same parameter as $NB_F$, up to additive and multiplicative constants (i.e. up to rescaling). We make the necessary work of comparison and unification of the results on $NB_F$, respectively on ambiguity, which have been obtained in the five papers devoted to these parameters. We generalize some known results to any Abelian groups and we more importantly derive many new results on these parameters.","Title: The Fifth International Students' Olympiad in Cryptography - NSUCRYPTO: problems and their solutions.\nYear: 2019\n\nAbstract: Problems and their solutions of the Fifth International Students? Olympiad in cryptography NSUCRYPTO?2018 are presented. We consider problems related to attacks on ciphers and hash functions, Boolean functions, quantum circuits, Enigma, etc. We discuss several open problems on orthogonal arrays, Sylvester matrices, and disjunct matrices. The problem of existing an invertible Sylvester matrix whose inverse is again a Sylvester matrix was completely solved during the Olympiad.","Title: Detecting Faults In Inner Productmasking Scheme Ipm-Fd: Ipm With Fault Detection (Extended Version*)\nYear: 2021\n\nAbstract: Side-channel analysis and fault injection attacks are two typical threats to cryptographic implementations, especially in modern embedded devices. Thus, there is an insistent demand for dual side-channel and fault injection protections. As we know, masking is a kind of provable countermeasure against side-channel attacks. Recently, inner product masking (IPM) was proposed as a promising higher-order masking scheme against side-channel analysis, but not for fault injection attacks. In this paper, we devise a new masking scheme named IPM-FD. It is built on IPM, which enables fault detection. This novel masking scheme has three properties: the security orders in the word-level probing model, bit-level probing model and the number of detected faults. IPM-FD is proven secure both in the word-level and in the bit-level probing models and allows for end-to-end fault detection against fault injection attacks. Furthermore, we illustrate its security order by interpreting IPM-FD as a coding problem and then linking it to one defining parameters of linear code and show its implementation cost by applying IPM-FD to AES-128.","Title: Evolutionary algorithms-assisted construction of cryptographic boolean functions\nYear: 2021\n\nAbstract: ABSTRACTIn the last few decades, evolutionary algorithms were successfully applied numerous times for creating Boolean functions with good cryptographic properties. Still, the applicability of such approaches was always limited as the cryptographic community knows how to construct suitable Boolean functions with deterministic algebraic constructions. Thus, evolutionary results so far helped to increase the confidence that evolutionary techniques have a role in cryptography, but at the same time, the results themselves were seldom used. This paper considers a novel problem using evolutionary algorithms to improve Boolean functions obtained through algebraic constructions. To this end, we consider a recent generalization of Hidden Weight Boolean Function construction, and we show that evolutionary algorithms can significantly improve the cryptographic properties of the functions. Our results show that the genetic algorithm performs by far the best of all the considered algorithms and improves the nonlinearity property in all Boolean function sizes. As there are no known algebraic techniques to reach the same goal, we consider this application a step forward in accepting evolutionary algorithms as a powerful tool in the cryptography domain.","Title: Bounds on the Nonlinearity of Differentially Uniform Functions by Means of Their Image Set Size, and on Their Distance to Affine Functions\nYear: 2021\n\nAbstract: We revisit and take a closer look at a (not so well known) result of a 2017 paper, showing that the differential uniformity of any vectorial function is bounded from below by an expression depending on the size of its image set. We make explicit the resulting tight lower bound on the image set size of differentially $\\delta $ ...","Title: A Wide Class of Boolean Functions Generalizing the Hidden Weight Bit Function\nYear: 2022\n\nAbstract: Designing Boolean functions whose output can be computed with light means at high speed, and satisfying all the criteria necessary to resist all major attacks on the stream ciphers using them as nonlinear components, has been an open problem since the beginning of this century, when algebraic attacks were invented. Functions allowing a good resistance are known since 2008, but their output is a li...","Title: Evolving Constructions for Balanced, Highly Nonlinear Boolean Functions\nYear: 2022\n\nAbstract: Finding balanced, highly nonlinear Boolean functions is a difficult problem where it is not known what nonlinearity values are possible to be reached in general. At the same time, evolutionary computation is successfully used to evolve specific Boolean function instances, but the approach cannot easily scale for larger Boolean function sizes. Indeed, while evolving smaller Boolean functions is almost trivial, larger sizes become increasingly difficult, and evolutionary algorithms perform suboptimally. In this work, we ask whether genetic programming (GP) can evolve constructions resulting in balanced Boolean functions with high nonlinearity. This question is especially interesting as there are only a few known such constructions. Our results show that GP can find constructions that generalize well, i.e., result in the required functions for multiple tested sizes. Further, we show that GP evolves many equivalent constructions under different syntactic representations. Interestingly, the simplest solution found by GP is a particular case of the well-known indirect sum construction.","Title: A Complete Study of Two Classes of Boolean Functions: Direct Sums of Monomials and Threshold Functions\nYear: 2022\n\nAbstract: In this paper, we make a comprehensive study of two classes of Boolean functions whose interest originally comes from hybrid symmetric-FHE encryption (with stream ciphers like FiLIP), but which also present much interest for general stream ciphers. The functions in these two classes are cheap and easy to implement, and they allow the resistance to all classical attacks and to their guess and deter..."],"string":"[\n \"Title: Generalized partial spreads\\nYear: 1995\\n\\nAbstract: We exhibit a simple condition under which the sum (modulo 2) of characteristic functions of (n/2)-dimensional vector subspaces of (GF(2))n (n even) is a Bent function. The “Fourier” transform of such a Bent function is the sum of the characteristic functions of the duals of these spaces. The class of Bent functions that we obtain contains the whole partial spreads class. Any element of Maiorana-McFarland's class or of class D is equivalent to one of its elements. Thus this new class gives a unified insight of both general classes of Bent functions studied by Dillon (1974) in his thesis. We deduce a way to construct new classes of Bent functions and exhibit an example\",\n \"Title: Highly nonlinear mappings\\nYear: 2004\\n\\nAbstract: Functions with high nonlinearity have important applications in cryptography, sequences and coding theory. The purpose of this paper is to give a well-rounded treatment of non-Boolean functions with optimal nonlinearity. We summarize and generalize known results, and prove a number of new results. We also present open problems about functions with high nonlinearity.\",\n \"Title: Side-channel indistinguishability.\\nYear: 2013\\n\\nAbstract: We introduce a masking strategy for hardware that prevents any side-channel attacker from recovering uniquely the secret key of a cryptographic device. In this masking scheme, termed homomorphic, the sensitive data is exclusive-ored with a random value that belongs to a given set. We show that if this masking set is concealed, then no information about the cryptographic key leaks. If the masking set is public (or disclosed), then any (high-order) attack reveals a group of equiprobable keys. Those results are applied to the case of the AES, where sensitive variables are bytes. To any mask corresponds a masked substitution box. We prove that there exists a homomorphic masking with 16 masks (hence a number of substitution boxes equal to that of the same algorithm without masking) that resists mono-variate first-, second-, and third-order side-channel attacks. Furthermore, even if the masking set is public, each byte of the correct key is found only ex æquo with 15 incorrect ones, making the side-channel analysis insufficient alone -- the remaining key space shall be explored by other means (typically exhaustive search). Thus, our homomorphic masking strategy allows both to increase the number of side-channel measurements and to demand for a final non negligible brute-forcing (of complexity 16NB = 264 for AES, that has NB = 16 substitution boxes). The hardware implementation of the Rotating Substitution boxes Masking (RSM) is a practical instantiation of our homomorphic masking countermeasure.\",\n \"Title: Partially-Bent Functions\\nYear: 1993\\n\\nAbstract: We study a conjecture stated in [6] about the numbers of non-zeros of, respectively, the auto-correlation function and the Walsh transform of the function (−1)\\n f(x), where f(x) is any boolean function on {0, 1}n. The result that we obtain leads us to introduce the class of partially-bent functions. We study within these functions the\\n propagation criterion. We characterize those partially-bent functions which are balanced and prove a relation between their\\n number (which is unknown) and the number of non-balanced partially-bent functions on {0, 1}\\n n−1. Eventually, we study their correlation immunity.\",\n \"Title: Preface: Volume 6\\nYear: 2001\\n\\nAbstract: The second International Workshop on Coding and Cryptography (WCC 2001) was held in January 8-12, 2001 at the “Cercle National des Armées”, Paris, France. It was jointly organized by INRIA (French National Institute for Research in Computer Science and Control) and the research center of the “Écoles de Coëtquidan”.\",\n \"Title: On known and new differentially uniform functions\\nYear: 2011\\n\\nAbstract: We give a survey on the constructions of APN and differentially 4-uniform functions suitable for designing S-boxes for block ciphers. We recall why the search for more of such functions is necessary. We propose a way of designing functions which can possibly be APN or differentially 4-uniform and be bijective. We illustrate it with an example of a differentially 4-uniform (n, n)-permutation for n odd, based on the power function x3 over the second order Galois extension of F2n+1, and related to the Dickson polynomial D3 over this field. These permutations have optimal algebraic degree and their nonlinearity happens to be rather good (but worse than that of the multiplicative inverse functions).\",\n \"Title: On the higher order nonlinearities of algebraic immune functions\\nYear: 2006\\n\\nAbstract: One of the most basic requirements concerning Boolean functions used in cryptosystems is that they must have high algebraic degrees. This simple criterion is not always well adapted to the concrete situation in which Boolean functions are used in symmetric cryptography, since changing one or several output bits of a Boolean function considerably changes its algebraic degree while it may not change its robustness. The proper characteristic is the r-th order nonlinearity profile (which includes the first-order nonlinearity). However, studying it is difficult and almost no paper, in the literature, has ever been able to give general effective results on it. The values of the nonlinearity profile are known for very few functions and these functions have little cryptographic interest. A recent paper has given a lower bound on the nonlinearity profile of functions, given their algebraic immunity. We improve upon it, and we deduce that it is enough, for a Boolean function, to have high algebraic immunity, for having non-weak low order nonlinearity profile (even when it cannot be evaluated), except maybe for the first order.\",\n \"Title: On Correlation-Immune Functions\\nYear: 1991\\n\\nAbstract: We establish the link between correlation-immune functions and orthogonal arrays. We give a recursive definition of any correlation-immune function of maximal degree. We describe the set of quadratic balanced correlation-immune functions of maximal order. Some constructions are then deduced.\",\n \"Title: Nonlinearities of S-boxes\\nYear: 2007\\n\\nAbstract: We introduce an indicator of the non-balancedness of functions defined over Abelian groups, and deduce a new indicator, denoted by NB, of the nonlinearity of such functions. We prove an inequality relating NB and the classical indicator NL, introduced by Nyberg and studied by Chabaud and Vaudenay, of the nonlinearity of S-boxes. This inequality results in an upper bound on NL which unifies Sidelnikov-Chabaud-Vaudenay's bound and the covering radius bound. We also deduce from bounds on linear codes three new bounds on NL that improve upon Sidelnikov-Chabaud-Vaudenay's bound and the covering radius bound in many cases.\",\n \"Title: Self-dual bent functions\\nYear: 2010\\n\\nAbstract: A bent function is called self-dual if it is equal to its dual. It is called anti-self-dual if it is equal to the complement of its dual. A spectral characterisation in terms of the Rayleigh quotient of the Sylvester Hadamard matrix is derived. Bounds on the Rayleigh quotient are given for Boolean functions in an odd number of variables. An efficient search algorithm based on the spectrum of the Sylvester matrix is derived. Primary and secondary constructions are given. All self-dual bent Boolean functions in ≤ 6 variables and all quadratic such functions in eight variables are given, up to a restricted form of affine equivalence.\",\n \"Title: On Semibent Boolean Functions\\nYear: 2012\\n\\nAbstract: We show that any Boolean function, in even dimension, equal to the sum of a Boolean function $g$ which is constant on each element of a spread and of a Boolean function $h$ whose restrictions to these elements are all linear, is semibent if and only if $g$ and $h$ are both bent. We deduce a large number of infinite classes of semibent functions in explicit bivariate (respectively, univariate) polynomial form.\",\n \"Title: Algebraic Attacks and Decomposition of Boolean Functions\\nYear: 2004\\n\\nAbstract: Algebraic attacks on LFSR-based stream ciphers recover the secret key by solving an overdefined system of multivariate algebraic equations. They exploit multivariate relations involving key bits and output bits and become very efficient if such relations of low degrees may be found. Low degree relations have been shown to Exist for several well known constructions of stream ciphers immune to all previously known attacks. Such relations may be derived by multiplying the output function of a stream cipher by a well chosen low degree function such that the product function is again of low degree. In view of algebraic attacks, low degree multiples of Boolean functions are a basic concern in the design of stream ciphers as well as of block ciphers. This paper investigates the existence of low degree multiples of Boolean functions in several directions: The known scenarios under which low degree multiples exist are reduced and simplified to two scenarios, that are treated differently in algebraic attacks. A new algorithm is proposed that allows to successfully decide whether a Boolean function has low degree multiples. This represents a significant step towards provable security against algebraic attacks. Furthermore, it is shown that a recently introduced class of degree optimized Maiorana-McFarland functions immanently has low degree multiples. Finally, the probability that a random Boolean function has a low degree multiple is estimated.\",\n \"Title: On the Propagation Criterion of Degree l and Order k\\nYear: 1998\\n\\nAbstract: We determine those Boolean functions on GF(2)(n) which satisfy the propagation criterion of degree l and order k greater than or equal to n - l - 2. All of theses functions are quadratic. We design nonquadratic Boolean functions satisfying the criterion PC(l) of order k by using the Maiorana-McFarland construction involving nonlinear mappings derived from nonlinear codes.\",\n \"Title: An Infinite Class of Balanced Functions with Optimal Algebraic Immunity, Good Immunity to Fast Algebraic Attacks and Good Nonlinearity\\nYear: 2008\\n\\nAbstract: After the improvement by Courtois and Meier of the algebraic attacks on stream ciphers and the introduction of the related notion of algebraic immunity, several constructions of infinite classes of Boolean functions with optimum algebraic immunity have been proposed. All of them gave functions whose algebraic degrees are high enough for resisting the Berlekamp-Massey attack and the recent Rønjom-Helleseth attack, but whose nonlinearities either achieve the worst possible value (given by Lobanov's bound) or are slightly superior to it. Hence, these functions do not allow resistance to fast correlation attacks. Moreover, they do not behave well with respect to fast algebraic attacks. In this paper, we study an infinite class of functions which achieve an optimum algebraic immunity. We prove that they have an optimum algebraic degree and a much better nonlinearity than all the previously obtained infinite classes of functions. We check that, at least for small values of the number of variables, the functions of this class have in fact a very good nonlinearity and also a good behavior against fast algebraic attacks.\",\n \"Title: On the Higher Order Nonlinearities of Boolean Functions and S-Boxes, and Their Generalizations\\nYear: 2008\\n\\nAbstract: The r-th order nonlinearity of a Boolean function $f:F_2^n\\\\to F_2$ is its minimum Hamming distance to all functions of algebraic degrees at most r, where ris a positive integer. The r-th order nonlinearity of an S-box $F:F_2^n\\\\to F_2^m$ is the minimum r-th order nonlinearity of its component functions v·F, $v\\\\in F_2^m\\\\setminus \\\\{0\\\\}$. The role of this cryptographic criterion against attacks on stream and block ciphers has been illustrated by several papers. Its study is also interesting for coding theory and is related to the covering radius of Reed-Muller codes (i.e. the maximum multiplicity of errors that have to be corrected when maximum likelihood decoding is used on a binary symmetric channel). We give a survey of what is known on this parameter, including the bounds involving the algebraic immunity of the function, the bounds involving the higher order nonlinearities of its derivatives, and the resulting bounds on the higher order nonlinearities of the multiplicative inverse functions (used in the S-boxes of the AES). We show an improvement, when we consider an S-box instead of a Boolean function, of the bounds on the higher order nonlinearity expressed by means of the algebraic immunity. We study a generalization (for S-boxes) of the notion and we give new results on it.\",\n \"Title: On the Higher Order Nonlinearities of Boolean Functions and S-boxes\\nYear: 2009\\n\\nAbstract: This talk will be devoted to symmetric cryptography and more precisely to the Boolean functions it uses for making the systems as nonlinear as possible, allowing them to resist known attacks and hopefully future attacks. These are central objects for the design and the security of symmetric cryptosys- tems (stream ciphers and block ciphers).\",\n \"Title: On highly nonlinear s-boxes and their inability to thwart DPA attacks\\nYear: 2005\\n\\nAbstract: Prouff has introduced recently, at FSE 2005, the notion of transparency order of S-boxes. This new characteristic is related to the ability of an S-box, used in a cryptosystem in which the round keys are introduced by addition, to thwart single-bit or multi-bit DPA attacks on the system. If this parameter has sufficiently small value, then the S-box is able to withstand DPA attacks without that ad-hoc modifications in the implementation be necessary (these modifications make the encryption about twice slower). We prove a lower bound on the transparency order of highly nonlinear S-boxes. We show that some highly nonlinear functions, and in particular the S-box of AES, have very bad transparency orders.\",\n \"Title: A New Class of Codes for Boolean Masking of Cryptographic Computations\\nYear: 2011\\n\\nAbstract: We introduce a new class of rate one-half binary codes: complementary information set codes. A binary linear code of length $2n$ and dimension $n$ is called a complementary information set code (CIS code for short) if it has two disjoint information sets. This class of codes contains self-dual codes as a subclass. It is connected to graph correlation immune vectorial Boolean functions of use in the security of hardware implementations of cryptographic primitives. Such codes permit to improve the cost of masking cryptographic algorithms against side channel attacks. In this paper, we investigate this new class of codes: we give optimal or best known CIS codes of length $ < 132$. We derive general constructions based on cyclic codes and on double circulant codes. We derive a Varshamov–Gilbert bound for long CIS codes, and show that they can all be classified in small lengths $\\\\leq 12$ by the building up construction. Some nonlinear permutations are constructed by using ${\\\\BBZ}_{4}$-codes, based on the notion of dual distance of a possibly nonlinear code.\",\n \"Title: A characterization of binary bent functions\\nYear: 1996\\n\\nAbstract: A paper presented by Carlet (see IEEE Transactions on Information Theory, vol.41, p.1482-7, 1995) introduces a general class of binary bent functions whose elements are expressed by means of indicators of n/2-dimensional vector-subspaces of (GF(2))n . An extended version of this class is introduced in the same paper where it is conjectured that this version is equal to the whole class of bent functions. We prove now that this conjecture is true\",\n \"Title: Secondary Constructions of Bent Functions and Highly Nonlinear Resilient Functions\\nYear: 2012\\n\\nAbstract: In this paper, we first present a new secondary construction of bent functions (building new bent functions from two already defined ones). Furthermore, we apply the construction using as initial functions some specific bent functions and then provide several concrete constructions of bent functions. The second part of the paper is devoted to the constructions of resilient functions. We give a generalization of the indirect sum construction for constructing resilient functions with high nonlinearity. In addition, we modify the generalized construction to ensure a high nonlinearity of the constructed function.\",\n \"Title: Propagation characteristics and correlation-immunity of highly nonlinear boolean functions\\nYear: 2000\\n\\nAbstract: We investigate the link between the nonlinearity of a Boolean function and its propagation characteristics. We prove that highly nonlinear functions usually have good propagation properties regarding different criteria. Conversely, any Boolean function satisfying the propagation criterion with respect to a linear subspace of codimension 1 or 2 has a high nonlinearity. We also point out that most highly nonlinear functions with a three-valued Walsh spectrum can be transformed into 1-resilient functions.\",\n \"Title: Hyper-bent functions and cyclic codes\\nYear: 2006\\n\\nAbstract: Bent functions are those Boolean functions whose Hamming distance to the Reed-Muller code of order 1 equal 2n-1) - 2n/2-1 (where the number n of variables is even). These combinatorial objects, with fascinating properties, are rare. Few constructions are known, and it is difficult to know whether the bent functions they produce are peculiar or not, since no way of generating at random bent functions on 8 variables or more is known.The class of bent functions contains a subclass of functions whose properties are still stronger and whose elements are still rarer. Youssef and Gong have proved the existence of such hyperbent functions, for every even n. We prove that the hyper-bent functions they exhibit are exactly those elements of the well-known PIap class, introduced by Dillon, up to the linear transformations x ↦ δx, δ ∈ F2n*. Hyper-bent functions seem still more difficult to generate at random than bent functions; however, by showing that they all can be obtained from some codewords of an extended cyclic code Hn with small dimension, we can enumerate them for up to 10 variables. We study the non-zeroes of Hn and we deduce that the algebraic degree of hyper-bent functions is n/2. We also prove that the functions of class PIap are some codewords of weight 2n-1 - 2n/2-1 of a subcode of Hn and we deduce that for some n, depending on the factorization of 2n - 1, the only hyperbent functions on n variables are the elements of the class PIap#, obtained from PIap by composing the functions by the transformations x ↦ δx, δ ≠ 0, and by adding constant functions. We prove that non-PIap# hyper-bent functions exist for n = 4, but it is not clear whether they exist for greater n. We also construct potentially new bent functions for n = 12.\",\n \"Title: Codes, Bent Functions and Permutations Suitable For DES-like Cryptosystems\\nYear: 1998\\n\\nAbstract: Almost bent functions oppose an optimum resistance to linear and differential cryptanalysis. We present basic properties of almost bent functions; particularly we give an upper bound on the degree. We develop the \\\"coding theory\\\" point of view for studying the existence of almost bent functions, showing explicitly the links with cyclic codes. We also give new characterizations of almost bent functions by means of associated Boolean functions.\",\n \"Title: Further properties of several classes of Boolean functions with optimum algebraic immunity\\nYear: 2007\\n\\nAbstract: Based on a method proposed by the first author, several classes of balanced Boolean functions with optimum algebraic immunity are constructed, and they have nonlinearities significantly larger than the previously best known nonlinearity of functions with optimal algebraic immunity. By choosing suitable parameters, the constructed n-variable functions have nonlinearity $${2^{n-1}-{n-1\\\\choose\\\\frac{n}{2}-1}+2{n-2\\\\choose\\\\frac{n}{2}-2}\\\\Big/(n-2)}$$ for even $${n\\\\geq 8\\\\,{\\\\rm and}\\\\,2^{n-1}-{n-1\\\\choose\\\\frac{n-1}{2}}+\\\\Delta(n)}$$ for odd n, where Δ(n) is a function increasing rapidly with n. The algebraic degrees of some constructed functions are also discussed.\",\n \"Title: On the second-order nonlinearities of some bent functions\\nYear: 2013\\n\\nAbstract: The rth-order nonlinearity of Boolean functions plays a central role against several known attacks on stream and block ciphers. It plays also an important role in coding theory, since its maximum equals the covering radius of the rth-order Reed-Muller code. But it is difficult to calculate and even to bound. In this paper, we show lower bounds on the second-order nonlinearity of two subclasses of well-known bent functions. We first improve a known lower bound on the second-order nonlinearity of the simplest partial spread bent functions, whose nonlinearity profile has been bounded by the second author. This improvement allows obtaining a better bound for the whole profile. We subsequently give a lower bound on the second-order nonlinearity of some infinite class of Maiorana-McFarland (M-M) bent functions, which generalizes a result by Gangopadhyay et al.\",\n \"Title: On bent and highly nonlinear balanced/resilient functions and their algebraic immunities\\nYear: 2006\\n\\nAbstract: Since the introduction of the notions of nonlinearity in the mid-70’s (the term has been in fact introduced later), of correlation immunity and resiliency in the mid-80’s, and of algebraic immunity recently, the problem of efficiently constructing Boolean functions satisfying, at high levels, one or several of these criteria has received much attention. Only few primary constructions are known, and secondary constructions are also necessary to obtain functions achieving or approaching the best possible cryptographic characteristics. After recalling the background on cryptographic criteria and making some general observations, we try to give a survey of all these constructions and their properties. We then show that a nice and simple property of Boolean functions leads to a general secondary construction building an n-variable function from three known n-variable functions. This construction generalizes secondary constructions recently obtained for Boolean bent functions and also leads to secondary constructions of highly nonlinear balanced or resilient functions, with potentially better algebraic immunities than the three functions used as building blocks.\",\n \"Title: Constructing new APN functions from known ones\\nYear: 2007\\n\\nAbstract: We present a method for constructing new quadratic APN functions from known ones. Applying this method to the Gold power functions we construct an APN function x^3+tr(x^9) over F\\\"2\\\"^\\\"n. It is proven that for n=7 this function is CCZ-inequivalent to the Gold functions, and in the case n=7 it is CCZ-inequivalent to any power mapping (and, therefore, to any APN function belonging to one of the families of APN functions known so far).\",\n \"Title: Improving the algebraic immunity of resilient and nonlinear functions and constructing bent functions\\nYear: 2004\\n\\nAbstract: The currently known constructions of Boolean functions with high nonlinearities, high algebraic degrees and high resiliency or- ders do not seem to permit achieving suciently high algebraic immunities. We introduce a construction of Boolean functions, which builds a new function from three known ones. Assuming that the three functions have some resiliency order, nonlinearity and algebraic degree, as well as their sum modulo 2, the con- structed function has the same resiliency order and can have the same nonlinearity, but has potentially better algebraic degree and algebraic immunity. The set of classical constructions together with this new one (and with a simpler derived one, having the same advantages) permit now to obtain functions achieving all necessary criteria for being used in the pseudo-random generators in stream ciphers. We also apply this construction to obtain bent functions from known ones.\",\n \"Title: An Infinite Class of Balanced Vectorial Boolean Functions with Optimum Algebraic Immunity and Good Nonlinearity\\nYear: 2009\\n\\nAbstract: In this paper, we study the cryptographic properties of an infinite class of balanced vectorial Boolean functions recently introduced by Feng, Liao and Yang. These functions provably achieve an optimum algebraic immunity. We give a simpler proof of this fact and we prove that these functions have also an optimum algebraic degree and a non-weak nonlinearity.\",\n \"Title: Two new classes of bent functions\\nYear: 1993\\n\\nAbstract: We introduce a new class of bent functions on (GF(2))n ( n even). We prove that this class is not included in one of the known classes of bent functions, and that, when n equals 6, it covers the whole set of bent functions of degree 3. This class is obtained by using a result from J.F. Dillon. We generalize this result and deduce a second new class of bent functions which we checked was not included in one of the preceding ones.\",\n \"Title: An Alternate Characterization of the Bentness of Binary Functions, with Uniqueness\\nYear: 1998\\n\\nAbstract: In a previous paper, we have obtained a characterization of the binary bent functions on (GF(2))n (n even) as linear combinations modulo \\n$$2^{\\\\frac{n}{2}}$$\\n, with integral coefficients, of characteristic functions (indicators) of \\n$$\\\\frac{n}{2}$$\\n-dimensional vector-subspaces of (GF(2))n. There is no uniqueness of the representation of a given bent function related to this characterization. We obtain now a new characterization for which there is uniqueness of the representation.\",\n \"Title: Bent functions on a Galois ring and systematic authentication codes.\\nYear: 2012\\n\\nAbstract: A class of bent functions on a Galois ring is introduced and based on these functions systematic authentication codes are presented. These codes generalize those appearing in [4] for finite fields.\",\n \"Title: More correlation-immune and resilient functions over Galois fields and Galois rings\\nYear: 1997\\n\\nAbstract: We show that the usual constructions of bent functions, when they are suitably modified, allow constructions of correlation-immune and resilient functions over Galois fields and, in some cases, over Galois rings.\",\n \"Title: Generalized correlation analysis of Vectorial Boolean functions\\nYear: 2007\\n\\nAbstract: We investigate the security of n-bit to m-bit vectorial Boolean functions in stream ciphers. Such stream ciphers have higher throughput than those using single-bit output Boolean functions. However, as shown by Zhang and Chan at Crypto 2000, linear approximations based on composing the vector output with any Boolean functions have higher bias than those based on the usual correlation attack. In this paper, we introduce a new approach for analyzing vector Boolean functions called generalized correlation analysis. It is based on approximate equations which are linear in the input x but of free degree in the output z = F(x). Based on experimental results, we observe that the new generalized correlation attack gives linear approximation with much higher bias than the Zhang-Chan and usual correlation attacks. Thus it can be more effective than previous methods. First, the complexity for computing the generalized nonlinearity for this new attack is reduced from 22m×n+n to 22n. Second, we prove a theoretical upper bound for generalized nonlinearity which is much lower than the unrestricted nonlinearity (for Zhang-Chan's attack) or usual nonlinearity. This again proves that generalized correlation attack performs better than previous correlation attacks. Third, we introduce a generalized divide-and-conquer correlation attack and prove that the usual notion of resiliency is enough to protect against it. Finally, we deduce the generalized nonlinearity of some known secondary constructions for secure vector Boolean functions.\",\n \"Title: On the construction of bent vectorial functions\\nYear: 2010\\n\\nAbstract: Some properties of power permutations, that is, monomials bijective mappings on double-struck capital F<SUB align=right>2<SUP align=right>n</SUP>, are investigated. In particular, the differential ...\",\n \"Title: Higher-Order masking schemes for s-boxes\\nYear: 2012\\n\\nAbstract: Masking is a common countermeasure against side-channel attacks. The principle is to randomly split every sensitive intermediate variable occurring in the computation into d+1 shares, where d is called the masking order and plays the role of a security parameter. The main issue while applying masking to protect a block cipher implementation is to design an efficient scheme for the s-box computations. Actually, masking schemes with arbitrary order only exist for Boolean circuits and for the AES s-box. Although any s-box can be represented as a Boolean circuit, applying such a strategy leads to inefficient implementation in software. The design of an efficient and generic higher-order masking scheme was hence until now an open problem. In this paper, we introduce the first masking schemes which can be applied in software to efficiently protect any s-box at any order. We first describe a general masking method and we introduce a new criterion for an s-box that relates to the best efficiency achievable with this method. Then we propose concrete schemes that aim to approach the criterion. Specifically, we give optimal methods for the set of power functions, and we give efficient heuristics for the general case. As an illustration we apply the new schemes to the DES and PRESENT s-boxes and we provide implementation results.\",\n \"Title: Piecewise Constructions of Bent and Almost Optimal Boolean Functions\\nYear: 2005\\n\\nAbstract: The first aim of this work was to generalize the techniques used in MacWilliams' and Sloane's presentation of the Kerdock code and develop a theory of piecewise quadratic Boolean functions. This generalization led us to construct large families of potentially new bent and almost optimal functions from quadratic forms in this piecewise fashion. We show how our motivating example, the Kerdock code, fits into this setting. These constructions were further generalized to non-quadratic bent functions. The resulting constructions design n-variable bent (resp. almost optimal) functions from n-variable bent or almost optimal functions.\",\n \"Title: Secondary constructions of bent functions and their enforcement.\\nYear: 2012\\n\\nAbstract: Thirty years ago, Rothaus introduced the notion of bent function and presented a secondary construction (building new bent functions from already defined ones), which is now called the Rothaus construction. This construction has a strict requirement for its initial functions. In this paper, we first concentrate on the design of the initial functions in the Rothaus construction. We show how to construct Maiorana-McFarland's (M-M) bent functions, which can then be used as initial functions, from Boolean permutations and orthomorphic permutations. We deduce that at least (2(n)! x 2(2n))(2(2n) x 2(2n-1))(2) bent functions in 2n + 2 variables can be constructed by using Rothaus' construction. In the second part of the note, we present a new secondary construction of bent functions which generalizes the Rothaus construction. This construction requires initial functions with stronger conditions; we give examples of functions satisfying them. Further, we generalize the new secondary construction of bent functions and illustrate it with examples.\",\n \"Title: A general case of normal duality between binary nonlinear codes\\nYear: 1993\\n\\nAbstract: We give a general context in which a binary code C admits at least one code whose weight enumerator is dual to that of C. We study two examples of applications of this general result. The first one is the formal duality between the Kerdock and the generalized Preparata codes of same length and the second one gives a new example of dual weight enumerators.\",\n \"Title: Highly Nonlinear Boolean Functions With Optimal Algebraic Immunity and Good Behavior Against Fast Algebraic Attacks\\nYear: 2011\\n\\nAbstract: Inspired by the previous work of Tu and Deng, we propose two infinite classes of Boolean functions of $2k$ variables where $k\\\\\\\\geq 2$. The first class contains unbalanced functions having high algebraic degree and nonlinearity. The functions in the second one are balanced and have maximal algebraic degree and high nonlinearity (as shown by a lower bound that we prove; as a byproduct we also prove a better lower bound on the nonlinearity of the Carlet–Feng function). Thanks to a combinatorial fact, first conjectured by the authors and later proved by Cohen and Flori, we are able to show that they both possess optimal algebraic immunity. It is also checked that, at least for numbers of variables $n\\\\\\\\leq 16$, functions in both classes have a good behavior against fast algebraic attacks. Compared with the known Boolean functions resisting algebraic attacks and fast algebraic attacks, both of them possess the highest lower bounds on nonlinearity. These bounds are however not enough for ensuring a sufficient nonlinearity for allowing resistance to fast correlation attack. Nevertheless, as for previously found functions with the same features, there is a gap between the bound that we can prove and the actual values computed for bounded numbers of variables $(n\\\\\\\\leq 38)$. Moreover, these values are very good. The infinite class of functions we propose in Construction 2 presents, among all currently known constructions, the best provable tradeoff between all the important cryptographic criteria.\",\n \"Title: Construction of bent functions via Niho power functions\\nYear: 2006\\n\\nAbstract: A Boolean function with an even number n = 2k of variables is called bent if it is maximally nonlinear. We present here a new construction of bent functions. Boolean functions of the form f(x) = tr(α1xd1 + α2xd2), α1, α2, x ∈ F2n, are considered, where the exponents di (i = 1, 2) are of Niho type, i.e. the restriction of xdi on F2k is linear. We prove for several pairs of (d1, d2) that f is a bent function, when α1 and α2 fulfill certain conditions. To derive these results we develop a new method to prove that certain rational mappings on F2n, are bijective.\",\n \"Title: Efficient computation of algebraic immunity for algebraic and fast algebraic attacks\\nYear: 2006\\n\\nAbstract: In this paper we propose several efficient algorithms for assessing the resistance of Boolean functions against algebraic and fast algebraic attacks when implemented in LFSR-based stream ciphers. An algorithm is described which permits to compute the algebraic immunity d of a Boolean function with n variables in $\\\\mathcal{O}(D^2)$ operations, for $D \\\\approx \\\\binom{n}{d}$, rather than in $\\\\mathcal{O}(D^3)$ operations necessary in all previous algorithms. Our algorithm is based on multivariate polynomial interpolation. For assessing the vulnerability of arbitrary Boolean functions with respect to fast algebraic attacks, an efficient generic algorithm is presented that is not based on interpolation. This algorithm is demonstrated to be particularly efficient for symmetric Boolean functions. As an application it is shown that large classes of symmetric functions are very vulnerable to fast algebraic attacks despite their proven resistance against conventional algebraic attacks.\",\n \"Title: On Almost Perfect Nonlinear Functions\\nYear: 2008\\n\\nAbstract: A function F:F[unk]¿F[unk] is almost perfect nonlinear (APN) if, for every a¿0, b in F[unk], the equation F(x)+ F(x+a)=b has at most two solutions [4]. When used as an S-box in a block cipher, it opposes then an optimum resistance to differential cryptanalysis. The function F is almost bent (AB) if the minimum Hamming distance between all its component functions v·F, v ¿ F[unk]{0}, where \\\"·\\\" denotes any inner product in F[unk] and all affine Boolean functions on F[unk] takes the maximal value 2n-1 2(n-1)/2. AB functions exist for n odd only and oppose an optimum resistance to the linear cryptanalysis (see [3]). Every AB function is APN [3], and in the n odd case, any quadratic APN function is AB [2]. The APN and AB properties are preserved by affine equivalence: F~F' if F' = A1[unk] F[unk] A2, where A1, A2 are affine permutations. More generally, they are preserved by CCZ-equivalence [2], that is, affine equivalence of the graphs of F:{(x, F(x)) | x¿F[unk]} and of F'. Until recently, the only known constructions of APN and AB functions were CCZ-equivalent to power functions F(x)=xd over finite fields (F2n being identified with F[unk]).\",\n \"Title: The complexity of Boolean functions from cryptographic viewpoint\\nYear: 2006\\n\\nAbstract: Cryptographic Boolean functions must be complex to satisfy Shan- non's principle of confusion. But the cryptographic viewpoint on com- plexity is not the same as in circuit complexity. The two main criteria evaluating the cryptographic complexity of Boolean functions on F n 2 are the nonlinearity (and more generally the r-th order nonlinearity, for every positive r < n) and the algebraic degree. Two other criteria have also been considered: the algebraic thickness and the non-normality. After recalling the definitions of these criteria and why, asymptotically, almost all Boolean functions are deeply non-normal and have high algebraic de- grees, high (r-th order) nonlinearities and high algebraic thicknesses, we study the relationship between the r-th order nonlinearity and a recent cryptographic criterion called the algebraic immunity. This relationship strengthens the reasons why the algebraic immunity can be considered as a further cryptographic complexity criterion.\",\n \"Title: Optimal first-order masking with linear and non-linear bijections\\nYear: 2012\\n\\nAbstract: Hardware devices can be protected against side-channel attacks by introducing one random mask per sensitive variable. The computation throughout is unaltered if the shares (masked variable and mask) are processed concomitantly, in two distinct registers. Nonetheless, this setup can be attacked by a zero-offset second-order CPA attack. The countermeasure can be improved by manipulating the mask through a bijection F, aimed at reducing the dependency between the shares. Thus dth-order zero-offset attacks, that consist in applying CPA on the dth power of the centered side-channel traces, can be thwarted for d≥2 at no extra cost. We denote by n the size in bits of the shares and call F the transformation function, that is a bijection of $\\\\mathbb{F}_2^n$. In this paper, we explore the functions F that thwart zero-offset HO-CPA of maximal order d. We mathematically demonstrate that optimal choices for F relate to optimal binary codes (in the sense of communication theory). First, we exhibit optimal linear F functions. Second, we note that for values of n for which non-linear codes exist with better parameters than linear ones. These results are exemplified in the case n=8, the optimal F can be identified:it is derived from the optimal rate 1/2 binary code of size 2n, namely the Nordstrom-Robinson (16, 256, 6) code. This example provides explicitly with the optimal protection that limits to one mask of byte-oriented algorithms such as AES or AES-based SHA-3 candidates. It protects against all zero-offset HO-CPA attacks of order d≤5. Eventually, the countermeasure is shown to be resilient to imperfect leakage models.\",\n \"Title: More Vectorial Boolean Functions With Unbounded Nonlinearity Profile\\nYear: 2011\\n\\nAbstract: The nonlinearity profile of Boolean functions is a generalization of the most important cryptographic criterion, called the (first order) nonlinearity. It is defined as the sequence of the minimum Hamming distances nl(r)(f) between a given Boolean function f and all Boolean functions in the same number of variables and of degrees at most r, for r >= 1. This parameter, which has a close relationship with the Gowers norm, quantifies the resistance to cryptanalyses by low degree approximations of stream ciphers using the Boolean function f as combiner or as filter. The nonlinearity profile can also be defined for vectorial functions: it is the sequence of the minimum Hamming distances between the component functions of the vectorial function and all Boolean functions of degrees at most r, for r >= 1. The nonlinearity profile of the multiplicative inverse functions has been lower bounded in a previous paper by the same author. No other example of an infinite class of functions with unbounded nonlinearity profile has been exhibited since then. In this paper, we lower bound the whole nonlinearity profile of the (simplest) Dillon bent function (x, y) -> xy(2n/2-2), x, y is an element of F-2n/2 and we exhibit another class of functions, for which bounding the whole profile of each of them comes down to bounding the first order nonlinearities of all functions.\",\n \"Title: Two Classes of Quadratic APN Binomials Inequivalent to Power Functions\\nYear: 2008\\n\\nAbstract: This paper introduces the first found infinite classes of almost perfect nonlinear (APN) polynomials which are not Carlet-Charpin-Zinoviev (CCZ)-equivalent to power functions (at least for some values of the number of variables). These are two classes of APN binomials from F2n to F2n (for n divisible by 3, resp., 4). We prove that these functions are extended affine (EA)-inequivalent to any power function and that they are CCZ-inequivalent to the Gold, Kasami, inverse, and Dobbertin functions when n ges 12. This means that for n even they are CCZ-inequivalent to any known APN function. In particular, for n = 12,20,24, they are therefore CCZ-inequivalent to any power function.\",\n \"Title: Analysis of the algebraic side channel attack.\\nYear: 2012\\n\\nAbstract: At CHES 2009, Renauld, Standaert and Veyrat-Charvillon introduced a new kind of attack called algebraic side-channel attacks (ASCA). They showed that side-channel information leads to effective algebraic attacks. These results are mostly experiments since strongly based on the use of a SAT solver. This article presents a theoretical study to explain and to characterize the algebraic phase of these attacks. We study more general algebraic attacks based on Gröbner methods. We show that the complexity of the Gröbner basis computations in these attacks depends on a new notion of algebraic immunity defined in this paper, and on the distribution of the leakage information of the cryptosystem. We also study two examples of common leakage models: the Hamming weight and the Hamming distance models. For instance, the study in the case of the Hamming weight model gives that the probability of obtaining at least 64 (resp. 130) linear relations is about 50% for the substitution layer of PRESENT (resp. AES). Moreover if the S-boxes are replaced by functions maximizing the new algebraic immunity criterion then the algebraic attacks (Gröbner and SAT) are intractable. From this theoretical study, we also deduce an invariant which can be easily computed from a given S-box and provides a sufficient condition of weakness under an ASCA. This new invariant does not require any sophisticated algebraic techniques to be defined and computed. Thus, for cryptographic engineers without an advanced knowledge in algebra (e.g. Gröbner basis techniques), this invariant may represent an interesting tool for rejecting weak S-boxes.\",\n \"Title: On Plateaued Functions and Their Constructions\\nYear: 2003\\n\\nAbstract: We use the notion of covering sequence, introduced by C. Carlet and Y. Tarannikov, to give a simple characterization of bent functions. We extend it into a characterization of plateaued functions (that is bent and three-valued functions). After recalling why the class of plateaued functions provides good candidates to be used in cryptosystems, we study the known families of plateaued functions and their drawbacks. We show in particular that the class given as new by Zhang and Zheng is in fact a subclass of Maiorana-McFarland's class. We introduce a new class of plateaued functions and prove its good cryptographic properties.\",\n \"Title: Vectorial Functions and Covering Sequences\\nYear: 2003\\n\\nAbstract: The design of large classes of highly nonlinear resilient vectorial functions (mappings from F-2(n) into F-2(m), also called S-boxes) is needed for iterated block ciphers and for pseudo-random generators with multiple output. In this paper, we recall the diverse known constructions of such S-boxes, and we show that those which provide good candidate functions are, in fact, all in the same class. This class corresponds to a generalization of a well known construction due to Maiorana and MacFarland. We study in detail this construction and we specify it to obtain good S-boxes. In a second part, we generalize to S-boxes the notion of covering sequence. We show that this generalization has the same properties as for Boolean functions, and that it has nice additional properties of stability. We study how this notion can be used to design attacks, and we explain why some functions, including the elements of the new class, cannot be involved in the construction of iterated block ciphers.\",\n \"Title: Differentially 4-Uniform Bijections by Permuting the Inverse Function.\\nYear: 2013\\n\\nAbstract: Block ciphers use substitution boxes (S-boxes) whose aim is to create confusion into the cryptosystems. Functions used as S-boxes should have low differential uniformity, high nonlinearity and algebraic degree larger than 3 (preferably strictly larger). They should be fastly computable; from this viewpoint, it is better when they are in even number of variables. In addition, the functions should be bijections in a substitution-permutation network. Almost perfect nonlinear (APN) functions have the lowest differential uniformity 2 and the existence of APN bijections over for even is a big open problem. In the present paper, we focus on constructing differentially 4-uniform bijections suitable for designing S-boxes for block ciphers. Based on the idea of permuting the inverse function, we design a construction providing a large number of differentially 4-uniform bijections with maximum algebraic degree and high nonlinearity. For every even , we mathematically prove that the functions in a subclass of the constructed class are CCZ-inequivalent to known differentially 4-uniform power functions and to quadratic functions. This is the first mathematical proof that the functions in an infinite class of differentially 4-uniform bijections are CCZ-inequivalent to known differentially 4-uniform power functions and to quadratic functions. We also get a naive lower bound on the nonlinearity of our functions, which can be very high in some cases, and obtain improved lower bounds on the nonlinearity for three special subcases of functions which are extremely large.\",\n \"Title: CCZ-equivalence of bent vectorial functions and related constructions\\nYear: 2011\\n\\nAbstract: We observe that the CCZ-equivalence of bent vectorial functions over $${{\\\\bf F}_2^n}$$ (n even) reduces to their EA-equivalence. Then we show that in spite of this fact, CCZ-equivalence can be used for constructing bent functions which are new up to EA-equivalence and therefore to CCZ-equivalence: applying CCZ-equivalence to a non-bent vectorial function F which has some bent components, we get a function F驴 which also has some bent components and whose bent components are CCZ-inequivalent to the components of the original function F. Using this approach we construct classes of nonquadratic bent Boolean and bent vectorial functions.\",\n \"Title: Concatenating Indicators of Flats for Designing Cryptographic Functions\\nYear: 2005\\n\\nAbstract: Boolean functions with good cryptographic characteristics are needed for the design of robust pseudo-random generators for stream ciphers and of S-boxes for block ciphers. Very few general constructions of such cryptographic Boolean functions are known. The main ones correspond to concatenating affine or quadratic functions. We introduce a general construction corresponding to the concatenation of indicators of flats. We show that the functions it permits to design can present very good cryptographic characteristics.\",\n \"Title: PICARO: a block cipher allowing efficient higher-order side-channel resistance\\nYear: 2012\\n\\nAbstract: Many papers deal with the problem of constructing an efficient masking scheme for existing block ciphers. We take the reverse approach: that is, given a proven masking scheme (Rivain and Prouff, CHES 2010) we design a block cipher that fits well the masking constraints. The difficulty of implementing efficient masking for a block cipher comes mainly from the S-boxes. Therefore the choice of an adequate S-box is the first and most critical step of our work. The S-box we selected is non-bijective; we discuss the resulting design and security problems. A complete design of the cipher is given, as well as some implementation results.\",\n \"Title: Relating three nonlinearity parameters of vectorial functions and building APN functions from bent functions\\nYear: 2011\\n\\nAbstract: We survey the properties of two parameters introduced by C. Ding and the author for quantifying the balancedness of vectorial functions and of their derivatives. We give new results on the distribution of the values of the first parameter when applied to F + L, where F is a fixed function and L ranges over the set of linear functions: we show an upper bound on the nonlinearity of F by means of these values, we determine then the mean of these values and we show that their maximum is a nonlinearity parameter as well, we prove that the variance of these values is directly related to the second parameter. We briefly recall the known constructions of bent vectorial functions and introduce two new classes obtained with Gregor Leander. We show that bent functions can be used to build APN functions by concatenating the outputs of a bent (n, n/2)-function and of some other (n, n/2)-function. We obtain this way a general infinite class of quadratic APN functions. We show that this class contains the APN trinomials and hexanomials introduced in 2008 by L. Budaghyan and the author, and a class of APN functions introduced, in 2008 also, by Bracken et al.; this gives an explanation of the APNness of these functions and allows generalizing them. We also obtain this way the recently found Edel---Pott cubic function. We exhibit a large number of other sub-classes of APN functions. We eventually design with this same method classes of quadratic and non-quadratic differentially 4-uniform functions.\",\n \"Title: A Larger Class of Cryptographic Boolean Functions via a Study of the Maiorana-McFarland Construction\\nYear: 2002\\n\\nAbstract: Thanks to a new upper bound, we study more precisely the nonlinearities of Maiorana-McFarland's resilient functions. We characterize those functions with optimum nonlinearities and we give examples of functions with high nonlinearities. But these functions have a peculiarity which makes them potentially cryptographically weak. We study a natural super-class of Maiorana-McFarland's class whose elements do not have the same drawback and we give examples of such functions achieving high nonlinearities.\",\n \"Title: An Upper Bound on the Number of m-Resilient Boolean Functions\\nYear: 2002\\n\\nAbstract: The enumeration of m-resilient Boolean functions in n variables would be a quite useful information for cryptography. But it seems to be an intractable open problem. Upper and lower bounds have appeared in the literature in the mid 80驴s. Since then, improving them has been the goal of several papers. In this paper, we give a new upper bound which partially improves upon all the known bounds.\",\n \"Title: On Dillonʼs class H of bent functions, Niho bent functions and o-polynomials\\nYear: 2011\\n\\nAbstract: One of the classes of bent Boolean functions introduced by John Dillon in his thesis is family H . While this class corresponds to a nice original construction of bent functions in bivariate form, Dillon could exhibit in it only functions which already belonged to the well-known Maiorana–McFarland class. We first notice that H can be extended to a slightly larger class that we denote by H . We observe that the bent functions constructed via Niho power functions, for which four examples are known due to Dobbertin et al. and to Leander and Kholosha, are the univariate form of the functions of class H . Their restrictions to the vector spaces ω F 2 n / 2 , ω ∈ F 2 n ⋆ , are linear. We also characterize the bent functions whose restrictions to the ω F 2 n / 2 ʼs are affine. We answer the open question raised by Dobbertin et al. (2006) in [11] on whether the duals of the Niho bent functions introduced in the paper are affinely equivalent to them, by explicitly calculating the dual of one of these functions. We observe that this Niho function also belongs to the Maiorana–McFarland class, which brings us back to the problem of knowing whether H (or H ) is a subclass of the Maiorana–McFarland completed class. We then show that the condition for a function in bivariate form to belong to class H is equivalent to the fact that a polynomial directly related to its definition is an o-polynomial (also called oval polynomial, a notion from finite geometry). Thanks to the existence in the literature of 8 classes of nonlinear o-polynomials, we deduce a large number of new cases of bent functions in H , which are potentially affinely inequivalent to known bent functions (in particular, to Maiorana–McFarlandʼs functions).\",\n \"Title: Asymptotic lower bound on the algebraic immunity of random balanced multi-output Boolean functions.\\nYear: 2013\\n\\nAbstract: This paper extends the work of F. Didier (IEEE Transactions on Information Theory, Vol. 52(10): 4496 4503, October 2006) on the algebraic immunity of random balanced Boolean functions, into an asymptotic lower bound on the algebraic immunity of random balanced multi-output Boolean functions.\",\n \"Title: Achieving side-channel high-order correlation immunity with leakage squeezing.\\nYear: 2014\\n\\nAbstract: This article deeply analyzes high-order (HO) Boolean masking countermeasures against side-channel attacks in contexts where the shares are manipulated simultaneously and the correlation coefficient is used as a statistical distinguisher. The latter attacks are sometimes referred to as zero-offset high-order correlation power analysis (HO-CPA). In particular, the main focus is to get the most out of a single mask (i.e., for masking schemes with two shares). The relationship between the leakage characteristics and the attack efficiency is thoroughly studied. Our main contribution is to link the minimum attack order (called HO-CPA immunity) to the amount of information leaked. Interestingly, the HO-CPA immunity can be much larger than the number of shares in the masking scheme. This is made possible by the leakage squeezing. It is a variant of the Boolean masking where masks are recoded relevantly by bijections. This technique and others from the state-of-the-art (namely leak-free masking and wire-tap codes) are overviewed, and put in perspective.\",\n \"Title: Constructions of Quadratic and Cubic Rotation Symmetric Bent Functions\\nYear: 2012\\n\\nAbstract: In this paper, we consider constructions of rotation symmetric bent functions, which are of the forms: $f_{c}(x)=\\\\\\\\sum _{i=1}^{m-1}c_{i}(\\\\\\\\sum _{j=0}^{n-1}x_{j}x_{i+j}) +c_{m}(\\\\\\\\sum _{j=0}^{m-1}x_{j}x_{m+j}) $ and $f_{t}(x)=\\\\\\\\sum _{i=0}^{n-1}(x_{i}x_{t+i}x_{m+i}+x_{i}x_{t+i}) + \\\\\\\\sum _{i=0}^{m-1}x_{i}x_{m+i}$ , where $n=2m$, $ c_{i} \\\\\\\\in \\\\\\\\{0,1\\\\\\\\}$ (the subscript $u$ of $x_{u}$ in the previous expressions is taken as $u$ modulo $n$ ). For each case, a necessary and sufficient condition is obtained. To the best of our knowledge, this class of cubic rotation symmetric bent functions is the first example of an infinite class of nonquadratic rotation symmetric bent functions.\",\n \"Title: On the confusion and diffusion properties of Maiorana-McFarland's and extended Maiorana-McFarland's functions\\nYear: 2004\\n\\nAbstract: A practical problem in symmetric cryptography is finding constructions of Boolean functions leading to reasonably large sets of functions satisfying some desired cryptographic criteria. The main known construction, called Maiorana-McFarland, has been recently extended. Some other constructions exist, but lead to smaller classes of functions. Here, we study more in detail the nonlinearities and the resiliencies of the functions produced by all these constructions. Further we see how to obtain functions satisfying the propagation criterion (among which bent functions) with these methods, and we give a new construction of bent functions based on the extended Maiorana-McFarland's construction.\",\n \"Title: Authentication Schemes from Highly Nonlinear Functions\\nYear: 2006\\n\\nAbstract: We construct two families of authentication schemes using highly nonlinear functions on finite fields of characteristic 2. This leads to improvements on an earlier construction by Ding and Niederreiter if one chooses, for instance, an almost bent function as the highly nonlinear function\",\n \"Title: On the dual of bent functions with 2r Niho exponents\\nYear: 2011\\n\\nAbstract: Computed is the dual of the Niho bent function consisting of 2r exponents that was found by Leander and Kholosha. The algebraic degree of the dual is calculated and it is shown that this new bent function is not of the Niho type. This note is a follow-up of the recent paper by Carlet and Mesnager.\",\n \"Title: A transformation of boolean functions, its consequences on some problems related to Reed-Muller codes\\nYear: 1990\\n\\nAbstract: We introduce a transformation defined on the set of all boolean functions defined on Galois fields GF(2m), m*,(or on F\\n2\\nm\\n), which changes their weights in a way easy to be followed, and which, when we iterate it, reduces their degrees down to 2 or 3. We deduce that it is as difficult to find a general characterization of the weights in the Reed-Muller codes of order 3 as it is to obtain one in the Reed-Muller codes of any orders. We also use this transformation to characterize the existence of some affine sets of bent functions, and to obtain bent functions of degree 4 from bent functions of degree 3.\",\n \"Title: The automorphism groups of the Delsarte-Goethals codes\\nYear: 1993\\n\\nAbstract: We determine the automorphism groups of the Delsarte-Goethals codesDG(m, d) (m=2t+2=6, 2=d=t). The groups that we obtain are the same as those of the Kerdock codesK(m) of the same length.\",\n \"Title: On Cryptographic Propagation Criteria for Boolean Functions\\nYear: 1999\\n\\nAbstract: We determine the functions on GF(2)n which satisfy the propagation criterion of degree n¿2, PC(n¿2). We study subsequently the propagation criterion of degree ¿ and order k and its extended version EPC. We determine those Boolean functions on GF(2)n which satisfy PC(¿) of order k¿n¿¿¿2. We show that none of them satisfies EPC(¿) of the same order. We finally give a general construction of nonquadratic functions satisfying EPC(¿) of order k. This construction uses the existence of nonlinear, systematic codes with good minimum distances and dual distances (e.g., Kerdock codes and Preparata codes).\",\n \"Title: On a New Notion of Nonlinearity Relevant to Multi-output Pseudo-random Generators\\nYear: 2003\\n\\nAbstract: Vectorial functions (i.e. mappings from F-2(n) into F-2(m), also called S-boxes) can be used in pseudo-random generators with multiple outputs. The notion of maximum correlation of these S-boxes to linear functions, introduced by Zhang and Chan, plays a central role in the resistance of the resulting stream ciphers to correlation attacks. It can be related to a notion of \\\"unrestricted nonlinearity\\\". We obtain a new lower bound on the overall maximum correlation to linear functions of vectorial functions which results in an upper bound on the unrestricted nonlinearity. We compare it with the known upper bounds on the nonlinearity (which are also valid for the unrestricted nonlinearity of balanced functions). We study its tightness and we exhibit a class of balanced functions whose nonlinearity and unrestricted nonlinearity are high relatively to the upper-bounds.\",\n \"Title: Orthogonal Direct Sum Masking A Smartcard Friendly Computation Paradigm In A Code, With Builtin Protection Against Side-Channel And Fault Attacks\\nYear: 2014\\n\\nAbstract: Secure elements, such as smartcards or trusted platform modules (TPMs), must be protected against implementation-level attacks. Those include side-channel and fault injection attacks. We introduce ODSM, Orthogonal Direct Sum Masking, a new computation paradigm that achieves protection against those two kinds of attacks. A large vector space is structured as two supplementary orthogonal subspaces. One subspace (called a code C) is used for the functional computation, while the second subspace carries random numbers. As the random numbers are entangled with the sensitive data, ODSM ensures a protection against (monovariate) side-channel attacks. The random numbers can be checked either occasionally, or globally, thereby ensuring a detection capability. The security level can be formally detailed: it is proved that monovariate side-channel attacks of order up to dC-1, where dC is the minimal distance of C, are impossible, and that any fault of Hamming weight strictly less than dC is detected. A complete instantiation of ODSM is given for AES. In this case, all monovariate side-channel attacks of order strictly less than 5 are impossible, and all fault injections perturbing strictly less than 5 bits are detected.\",\n \"Title: On the arithmetic Walsh coefficients of Boolean functions\\nYear: 2014\\n\\nAbstract: We generalize to the arithmetic Walsh transform (AWT) some results which were previously known for the Walsh---Hadamard transform of Boolean functions. We first generalize the classical Poisson summation formula to the AWT. We then define a generalized notion of resilience with respect to an arbitrary statistical measure of Boolean functions. We apply the Poisson summation formula to obtain a condition equivalent to resilience for one such statistical measure. Last, we show that the AWT of a large class of Boolean functions can be expressed in terms of the AWT of a Boolean function of algebraic degree at most three in a larger number of variables.\",\n \"Title: Secondary constructions of highly nonlinear Boolean functions and disjoint spectra plateaued functions\\nYear: 2014\\n\\nAbstract: In this paper, we modify a generalized indirect sum construction to construct functions with high nonlinearity. By utilizing the modified construction, highly nonlinear functions in (n+m) variables can be obtained from known bent functions in n variables and highly nonlinear functions in m variables. It is possible to obtain new (n+15)-variable functions with nonlinearity 2^n^+^1^5^-^1-2^(^n^+^1^5^-^1^)^/^2+20x2^n^/^2 and new 12-variable 2-resilient functions with nonlinearity 2000 and algebraic degree 8, which achieve optimal algebraic immunity. Moreover, the modified construction can also be used as an iterative construction of a quadruple of disjoint spectra plateaued functions. In addition, we present sufficient conditions for a quadruple of disjoint spectra plateaued functions to have no nonzero linear structure.\",\n \"Title: Quadratic Zero-Difference Balanced Functions, APN Functions and Strongly Regular Graphs.\\nYear: 2014\\n\\nAbstract: Let be a function from to itself and a positive integer. is called zero-difference -balanced if the equation has exactly solutions for all nonzero . As a particular case, all known quadratic planar functions are zero-difference 1-balanced; and some quadratic APN functions over are zero-difference 2-balanced. In this paper, we study the relationship between this notion and differential uniformity; we show that all quadratic zero-difference -balanced functions are differentially -uniform and we investigate in particular such functions with the form , where and where the restriction of to the set of all nonzero th powers in is an injection. We introduce new families of zero-difference -balanced functions. More interestingly, we show that the image set of such functions is a regular partial difference set, and hence yields strongly regular graphs; this generalizes the constructions of strongly regular graphs using planar functions by Weng et al. Using recently discovered quadratic APN functions on , we obtain new negative Latin square type strongly regular graphs.\",\n \"Title: Higher-Order CIS Codes\\nYear: 2014\\n\\nAbstract: We introduce complementary information set codes of higher order. A binary linear code of length tk and dimension k is called a complementary information set code of order t (t-CIS code for short) if it has t pairwise disjoint information sets. The duals of such codes permit to reduce the cost of masking cryptographic algorithms against side-channel attacks. As in the case of codes for error correction, given the length and the dimension of a t-CIS code, we look for the highest possible minimum distance. In this paper, this new class of codes is investigated. The existence of good long CIS codes of order 3 is derived by a counting argument. General constructions based on cyclic and quasi-cyclic codes and on the building up construction are given. A formula similar to a mass formula is given. A classification of 3-CIS codes of length ≤ 12 is given. Nonlinear codes better than linear codes are derived by taking binary images of Z4-codes. A general algorithm based on Edmonds' basis packing algorithm from matroid theory is developed with the following property: given a binary linear code of rate 1/t, it either provides t disjoint information sets or proves that the code is not t-CIS. Using this algorithm, all optimal or best known [tk, k] codes, where t = 3, 4, . . . , 256 and 1≤ k ≤⌊256/t⌋ are shown to be t-CIS for all such k and t, except for t = 3 with k = 44 and t = 4 with k = 37.\",\n \"Title: Guest Editorial\\nYear: 1999\\n\\nAbstract: The eight papers in this special section focus on fractional horsepower electric drives. The section covers a wide range of subjects, namely, machine designs, thermal exchange problems, vibration monitoring, and control techniques.\",\n \"Title: A secondary construction and a transformation on rotation symmetric functions, and their action on bent and semi-bent functions.\\nYear: 2014\\n\\nAbstract: We study more in detail the relationship between rotation symmetric (RS) functions and idempotents, in univariate and bivariate representations, and deduce a construction of bent RS functions from semi-bent RS functions. We deduce the first infinite classes found of idempotent and RS bent functions of algebraic degree more than 3. We introduce a transformation from any RS Boolean function f over GF(2)n into the idempotent Boolean function f′(z)=f(z,z2,…,z2n−1) over GF(2n), leading to another RS Boolean function. The trace representation of f′ is directly deduced from the algebraic normal form of f, but we show that f and f′, which have the same algebraic degree, are in general not affinely equivalent to each other. We exhibit infinite classes of functions f such that (1) f is bent and f′ is not (2) f′ is bent and f is not (3) f and f′ are both bent (we show that this is always the case for quadratic functions and we also investigate cubic functions).\",\n \"Title: A Class Of 1-Resilient Boolean Functions With Optimal Algebraic Immunity And Good Behavior Against Fast Algebraic Attacks\\nYear: 2014\\n\\nAbstract: Recently, Tang, Carlet and Tang presented a combinatorial conjecture about binary strings, allowing proving that all balanced functions in some infinite class they introduced have optimal algebraic immunity. Later, Cohen and Flori completely proved that the conjecture is true. These functions have good (provable or at least observable) cryptographic properties but they are not 1-resilient, which represents a drawback for their use as filter functions in stream ciphers. We propose a construction of an infinite class of 1-resilient Boolean functions with optimal algebraic immunity by modifying the functions in this class. The constructed functions have optimal algebraic degree, that is, meet the Siegenthaler bound, and high nonlinearity. We prove a lower bound on their non linearity but as for the Carlet-Feng functions and for the functions mentioned above, this bound is not enough for ensuring a nonlinearity sufficient for allowing resistance to the fast correlation attack. Nevertheless, as for previously found functions, With the same features, there is a gap between the bound that We can prove and the actual values computed for small numbers of variables. Our computations show that the functions in this class have very good nonlinearity and also good immunity to fast algebraic attacks. This is the first time that an infinite class of functions gathers all of the main criteria allowing these functions to be used as filters in stream ciphers.\",\n \"Title: Leakage Squeezing: Optimal Implementation And Security Evaluation\\nYear: 2014\\n\\nAbstract: Hardware devices can be protected against side-channel attacks by introducing one random mask per sensitive variable. The computation throughout is unaltered if the shares (masked variable and mask) are processed concomitantly, in two distinct registers. Nonetheless, this setup can still be attacked if the side-channel is squared, because this operation causes an interference between the two shares. This more sophisticated analysis is referred to as a zero-offset second-order correlation power analysis (CPA) attack. When the device leaks in Hamming distance, the countermeasure can be improved by the \\\"leakage squeezing\\\". It consists in manipulating the mask through a bijection, aimed at reducing the dependency between the shares' leakage. Thus dth-order zero-offset attacks, that consist in applying CPA on the dth power of the centered side-channel traces, can be thwarted for d >= 2 at no extra cost. We denote by a the size in bits of the shares and call F the transformation function, that is, a bijection of Viz. In this paper, we explore the functions F that thwart zero-offset high-order CPA (HO-CPA) of maximal order d. We mathematically demonstrate that optimal choices for F relate to optimal binary codes (in the sense of communication theory). First, we exhibit optimal linear F functions. They are suitable for masking schemes where only one mask is used throughout the algorithm. Second, we note that for values of n for which non-linear codes exist with better parameters than linear ones, better protection levels can be obtained. This applies to implementations in which each mask is randomly cast independently of the previous ones. These results are exemplified in the case rz = 8, where the optimal F can be identified: it is derived from the optimal rate 1/2 binary code of size 2n, namely the Nordstrom Robinson (16, 256, 6) code. This example provides explicitly with the optimal protection that limits to one mask of byte-oriented algorithms such as AES or AES-based SHA-3 candidates. It protects against all zero-offset HO-CPA attacks of order d <= 5. Eventually, the countermeasure is shown to be resilient to imperfect leakage models, where the registers leak differently than the sum of their toggling bits.\",\n \"Title: New Construction Of Differentially 4-Uniform Bijections\\nYear: 2013\\n\\nAbstract: Block ciphers use Substitution boxes (S-boxes) to create confusion into the cryptosystems. For resisting the known attacks on these cryptosystems, the following criteria for functions are mandatory: low differential uniformity, high nonlinearity and not low algebraic degree. Bijectivity is also necessary if the cipher is a Substitution-Permutation Network, and balancedness makes a Feistel cipher lighter. It is well-known that almost perfect nonlinear (APN) functions have the lowest differential uniformity 2 (the values of differential uniformity being always even) and the existence of APN bijections over F(2)n for even n >= 8 is a big open problem. In real practical applications, differentially 4-uniform bijections can be used as S-boxes when the dimension is even. For example, the AES uses a differentially 4-uniform bijection over F(2)8. In this paper, we first propose a method for constructing a large family of differentially 4-uniform bijections in even dimensions. This method can generate at least (2n(-3) - [2((n-1)/2-1)] -1).2(2n-1) such bijections having maximum algebraic degree n-1. Furthermore, we exhibit a subclass of functions having high nonlinearity and being CCZ-inequivalent to all known differentially 4-uniform power bijections and to quadratic functions.\",\n \"Title: Niho bent functions from quadratic o-monomials\\nYear: 2014\\n\\nAbstract: In this paper, we extend the class of Niho bent function consisting of 2r terms discovered by Leander and Kholosha. The extension is achieved by inserting coefficients of the power terms in the original function. Doing this, we obtain relation to all the existing quadratic o-monomials. We also calculate the algebraic degree of any function in the extended class.\",\n \"Title: An infinite class of quadratic APN functions which are not equivalent to power mappings\\nYear: 2005\\n\\nAbstract: We exhibit an infinite class of almost perfect nonlinear quadratic polynomials from F2n to F2n (n ≥ 12, n divisible by 3 but not by 9). We prove that these functions are EA-inequivalent to any power function. In the forthcoming version of the present paper we will proof that these functions are CCZ-inequivalent to any Gold function and to any Kasami function, in particular for n = 12, they are therefore CCZ-inequivalent to power functions.\",\n \"Title: On bent functions associated to AB functions\\nYear: 2011\\n\\nAbstract: In 1998, the second author, Charpin and Zinoviev characterized APN and AB (n, n)-functions by means of associated 2n-variable Boolean functions. In particular, they proved that a function F is AB if and only if the associated Boolean function γF is bent. This observation leads to potentially new bent functions associated to the known AB functions, or at least gives new insight on known bent functions. However, up to now, representations of γF are known only for Gold AB power functions and determining γF for the rest of AB functions is an open problem. In the present paper we determine γF for most of the known families of APN and AB functions.\",\n \"Title: Generalized bent functions and their relation to Maiorana-McFarland class\\nYear: 2012\\n\\nAbstract: In this paper, most of the known infinite classes of generalized bent functions are analyzed for their relation to the completed Maiorana-McFarland class. This is done using the criterion based on second-order derivatives of a function. In particular, it is shown that, unlike in the binary case, not all quadratic bent functions are EA-equivalent to a function of the Maiorana-McFarland type. This is the first attempt to rise this problem for the generalized bent functions.\",\n \"Title: On the nonlinearity of monotone Boolean functions.\\nYear: 2018\\n\\nAbstract: We prove a conjecture on the nonlinearity of monotone Boolean functions in even dimension, proposed in the recent paper “Cryptographic properties of monotone Boolean functions”, by Carlet et al. (J. Math. Cryptol. 10(1), 1–14, 2016). We also prove an upper bound on such nonlinearity, which is asymptotically much stronger than the conjectured upper bound and than the upper bound proved for odd dimension in this same paper. Contrary to these two previous bounds, which were not tight enough for allowing to clarify if monotone functions can have good nonlinearity, this new bound shows that the nonlinearity of monotone functions is always very bad, which represents a fatal cryptographic weakness of monotone Boolean functions; they are too closely approximated by affine functions for being usable as nonlinear components in cryptographic applications. We deduce a necessary criterion to be satisfied by a Boolean (resp. vectorial) function for being nonlinear.\",\n \"Title: Towards Stream Ciphers for Efficient FHE with Low-Noise Ciphertexts.\\nYear: 2016\\n\\nAbstract: Symmetric ciphers purposed for Fully Homomorphic Encryption FHE have recently been proposed for two main reasons. First, minimizing the implementation time and memory overheads that are inherent to current FHE schemes. Second, improving the homomorphic capacity, i.e. the amount of operations that one can perform on homomorphic ciphertexts before bootstrapping, which amounts to limit their level of noise. Existing solutions for this purpose suggest a gap between block ciphers and stream ciphers. The first ones typically allow a constant but small homomorphic capacity, due to the iteration of rounds eventually leading to complex Boolean functions hence large noise. The second ones typically allow a larger homomorphic capacity for the first ciphertext blocks, that decreases with the number of ciphertext blocks due to the increasing Boolean complexity of the stream ciphersu0027 output. In this paper, we aim to combine the best of these two worlds, and propose a new stream cipher construction that allows constant and smaller noise. Its main idea is to apply a Boolean filter function to a public bit permutation of a constant key register, so that the Boolean complexity of the stream cipher outputs is constant. We also propose an instantiation of the filter function designed to exploit recent 3rd-generation FHE schemes, where the error growth is quasi-additive when adequately multiplying ciphertexts with the same amount of noise. In order to stimulate further investigation, we then specify a few instances of this stream cipher, for which we provide a preliminary security analysis. We finally highlight the good properties of our stream cipher regarding the other goal of minimizing the time and memory complexity of calculus delegation for 2nd-generation FHEi¾?schemes. We conclude the paper with open problems related to the large design space opened by these new constructions.\",\n \"Title: Boolean and Vectorial Plateaued Functions and APN Functions\\nYear: 2015\\n\\nAbstract: Boolean plateaued functions and vectorial functions with plateaued components play a significant role in cryptography, sequences for communications, and the related combinatorics and designs. Our knowledge on them is not at a level corresponding to their importance. We introduce new characterizations of plateaued Boolean functions. We give the characterizations of vectorial functions whose compone...\",\n \"Title: Complementary dual codes for counter-measures to side-channel attacks.\\nYear: 2016\\n\\nAbstract: We recall why linear codes with complementary duals (LCD codes) play a role in counter-measures to passive and active side-channel analyses on embedded cryptosystems. The rate and the minimum distance of such LCD codes must be as large as possible. We recall the known primary construction of such codes with cyclic codes, and investigate other constructions, with expanded Reed-Solomon codes and generalized residue codes, for which we study the idempotents. These constructions do not allow to reach all the desired parameters. We study then those secondary constructions which preserve the LCD property, and we characterize conditions under which codes obtained by direct sum, direct product, puncturing, shortening, extending codes, or obtained by the Plotkin sum, can be LCD.\",\n \"Title: A new construction of differentially 4-uniform $(n, n-1)$-functions.\\nYear: 2015\\n\\nAbstract: In this paper, a new way to construct differentially 4-uniform (n, n 1)-functions is presented. As APN (n, n)-functions, these functions offer the best resistance against differential cryptanalysis and they can be used as substitution boxes in block ciphers with a Feistel structure. Constructing such functions is assumed to be as difficult as constructing APN (n, n)-functions. A function in our family of functions can be viewed as the concatenation of two APN (n 1,n 1)-functions satisfying some necessary conditions. Then, we study the special case of this construction in which the two APN functions differ by an affine function. Within this construction, we propose a family in which one of the APN functions is a Gold function which gives the quadratic differentially 4-uniform (n, n 1)-function (x, x(n)) -> x(2i) (+ 1) + x(n)x where x is an element of F-2(n-1) and x(n) is an element of F-2 with gcd (i,n - 1) = 1. We study the nonlinearity of this function in the case i = 1 because in this case we can use results from Carlitz which are unknown in the general case. We also give the Walsh spectrum of this function and prove that it is CCZ-inequivalent to functions of the form L o F where L is an affine surjective (n, n 1)-function and F is a known APN (n, n)-function for n <= 8, or the Inverse APN (n, n)-function for every n >= 5 odd, or any AB (n, n)-function for every n > 3 odd, or any Gold APN (n, n)-function for every n > 4 even.\",\n \"Title: Univariate Niho Bent Functions From o-Polynomials.\\nYear: 2014\\n\\nAbstract: In this paper, we discover that univariate form of a Niho bent function is a sum of functions having the form of a Leander-Kholosha bent function taken with particular coefficients from F*(2n) for every term. We know that the Niho bent functions are related to o-polynomials. The power terms in the univariate Niho bent function can be derived by working, in a first step, on each monomial of the cor...\",\n \"Title: S-boxes, Boolean Functions and Codes for the Resistance of Block Ciphers to Cryptographic Attacks, with or without Side Channels.\\nYear: 2015\\n\\nAbstract: The choice of functions $S: \\\\\\\\mathbb{F}_2^n\\\\\\\\mapsto \\\\\\\\mathbb{F}_2^m$ to be used as substitution boxes S-boxes, fastly implementable and contributing to resisting attacks is a crucial question for the design of block ciphers. We summary the state of the art in this domain, considering also the case m<n which has been less studied. We also recall the method for protecting block ciphers against side channel attacks SCA by masking, and how the S-boxes can be processed in order to ensure this protection. We state a related open problem, also interesting for its own sake. We eventually see how Boolean functions, vectorial functions and error correcting codes can be used in different ways for reducing the cost of masking while keeping the same resistance to some SCA and also for allowing resisting fault injection attacks FIA.\",\n \"Title: Polynomial Evaluation and Side Channel Analysis.\\nYear: 2016\\n\\nAbstract: Side Channel Analysis SCA is a class of attacks that exploits leakage of information from a cryptographic implementation during execution. To thwart it, masking is a common countermeasure. The principle is to randomly split every sensitive intermediate variable occurring in the computation into several shares and the number of shares, called the masking order, plays the role of a security parameter. The main issue while applying masking to protect a block cipher implementation is to specify an efficient scheme to secure the s-box computations. Several masking schemes, applicable for arbitrary orders, have been recently introduced. Most of them follow a similar approach originally introduced in the paper of Carlet et al. published at FSE 2012; the s-box to protect is viewed as a polynomial and strategies are investigated which minimize the number of field multiplications which are not squarings. This paper aims at presenting all these works in a comprehensive way. The methods are discussed, their differences and similarities are identified and the remaining open problems are listed.\",\n \"Title: On The Properties Of Vectorial Functions With Plateaued Components And Their Consequences On Apn Functions\\nYear: 2015\\n\\nAbstract: [This is an extended abstract of paper [15], which has been submitted to a journal] Boolean plateaued functions and vectorial functions with plateaued components, that we simply call plateaued, play a significant role in cryptography, but little is known on them. We give here, without proofs, new characterizations of plateaued Boolean and vectorial functions, by means of the value distributions of derivatives and of power moments of the Walsh transform. This allows us to derive several characterizations of APN functions in this framework, showing that all the main results known for quadratic APN functions extend to plateaued functions. Moreover, we prove that the APN-ness of those plateaued vectorial functions whose component functions are unbalanced depends only on their value distribution. This proves that any plateaued (n,n)-function, n even, having same value distribution as APN power functions, is APN and has same extended Walsh spectrum as the APN Gold functions.\",\n \"Title: Evolutionary Approach for Finding Correlation Immune Boolean Functions of Order t with Minimal Hamming Weight.\\nYear: 2015\\n\\nAbstract: The role of Boolean functions is prominent in several areas like cryptography, sequences and coding theory. Therefore, various methods to construct Boolean functions with desired properties are of direct interest. When concentrating on Boolean functions and their role in cryptography, we observe that new motivations and hence new properties have emerged during the years. It is important to note that there are still many design criteria left unexplored and this is where Evolutionary Computation can play a distinct role. One combination of design criteria that has appeared recently is finding Boolean functions that have various orders of correlation immunity and minimal Hamming weight. Surprisingly, most of the more traditionally used methods for Boolean function generation are inadequate in this domain. In this paper, we concentrate on a detailed exploration of several evolutionary algorithms and their applicability for this problem. Our results show that such algorithms are a viable choice when evolving Boolean functions with minimal Hamming weight and certain order of correlation immunity. This approach is also successful in obtaining Boolean functions with several values that were known previously to be theoretically optimal, but no one succeeded in finding actual Boolean functions with such values.\",\n \"Title: Optimized linear complementary codes implementation for hardware trojan prevention\\nYear: 2015\\n\\nAbstract: Block codes have been shown to be a tool to thwart hardware trojan horses. The state of the electronic circuits is encoded thanks to a pair of complementary codes: one code prevents a purported hardware trojan horses from triggering, while the other one detects any kind of payload. The feasibility and the actual implementation of such defense has be presented thanks to LCD (Linear Complementary Dual) codes and to LCP (Linear Complementary Pair) of codes. In this paper, we optimize the representation of such codes in order to reduce the hardware overhead of the countermeasure.\",\n \"Title: Algebraic Decomposition for Probing Security.\\nYear: 2015\\n\\nAbstract: The probing security model is very popular to prove the side-channel security of cryptographic implementations protected by masking. A common approach to secure nonlinear functions in this model is to represent them as polynomials over a binary field and to secure their nonlinear multiplications thanks to a method introduced by Ishai, Sahai and Wagner at Crypto 2003. Several schemes based on this approach have been published, leading to the recent proposal of Coron, Roy and Vivek which is currently the best known method when no particular assumption is made on the algebraic structure of the function. In the present paper, we revisit this idea by trading nonlinear multiplications for low-degree functions. Specifically, we introduce an algebraic decomposition approach in which a nonlinear function is represented as a sequence of functions with low algebraic degrees. We therefore focus on the probing-secure evaluation of such low-degree functions and we introduce three novel methods to tackle this particular issue. The paper concludes with a comparative analysis of the proposals, which shows that our algebraic decomposition method outperforms the method of Coron, Roy and Vivek in several realistic contexts.\",\n \"Title: Cryptographic properties of monotone Boolean functions.\\nYear: 2016\\n\\nAbstract: We prove various results on monotone Boolean functions. In particular, we prove a conjecture proposed recently, stating that there are no monotone bent Boolean functions. Further, we give an upper bound on the nonlinearity of monotone functions in odd dimension, we describe the Walsh-Hadamard spectrum and investigate some other cryptographic properties of monotone Boolean functions.\",\n \"Title: New secondary constructions of Bent functions.\\nYear: 2016\\n\\nAbstract: In this paper, we first present a novel secondary construction of bent functions (building new bent functions from two already defined ones). Furthermore, the algebraic degree and algebraic immunity of the constructed functions are analysed. Finally, we apply the construction using as initial functions some specific bent functions and then specify sufficient conditions for the resulting bent functions not to be contained in the completed Maiorana---McFarland class. In the second part of the paper, we present a corrigendum of \\\\\\\"Constructions of bent---negabent functions and their relation to the completed Maiorana---McFarland Class\\\\\\\" (IEEE Trans Inf Theory 61(3):1496---1506, 2015).\",\n \"Title: Boolean Functions With Restricted Input And Their Robustness; Application To The Flip Cipher\\nYear: 2017\\n\\nAbstract: We study the main cryptographic features of Boolean functions (balanced-ness, nonlinearity, algebraic immunity) when, for a given number n of variables, the input to these functions is restricted to some subset E of F-2(n). We study in particular the case when E equals the set of vectors of fixed Hamming weight, which plays a role in the FLIP stream cipher and we study the robustness of the Boolean function in this cipher.\",\n \"Title: Evolutionary Algorithms for Boolean Functions in Diverse Domains of Cryptography.\\nYear: 2016\\n\\nAbstract: The role of Boolean functions is prominent in several areas including cryptography, sequences, and coding theory. Therefore, various methods for the construction of Boolean functions with desired properties are of direct interest. New motivations on the role of Boolean functions in cryptography with attendant new properties have emerged over the years. There are still many combinations of design criteria left unexplored and in this matter evolutionary computation can play a distinct role. This article concentrates on two scenarios for the use of Boolean functions in cryptography. The first uses Boolean functions as the source of the nonlinearity in filter and combiner generators. Although relatively well explored using evolutionary algorithms, it still presents an interesting goal in terms of the practical sizes of Boolean functions. The second scenario appeared rather recently where the objective is to find Boolean functions that have various orders of the correlation immunity and minimal Hamming weight. In both these scenarios we see that evolutionary algorithms are able to find high-quality solutions where genetic programming performs the best.\",\n \"Title: Euclidean and Hermitian LCD MDS codes.\\nYear: 2018\\n\\nAbstract: Linear codes with complementary duals (abbreviated LCD) are linear codes whose intersection with their dual is trivial. When they are binary, they play an important role in armoring implementations against side-channel attacks and fault injection attacks. Non-binary LCD codes in characteristic 2 can be transformed into binary LCD codes by expansion. On the other hand, being optimal codes, maximum distance separable codes (abbreviated MDS) are of much interest from many viewpoints due to their theoretical and practical properties. However, little work has been done on LCD MDS codes. In particular, determining the existence of q-ary [n, k] LCD MDS codes for various lengths n and dimensions k is a basic and interesting problem. In this paper, we firstly study the problem of the existence of q-ary [n, k] LCD MDS codes and solve it for the Euclidean case. More specifically, we show that for \\\\(q>3\\\\) there exists a q-ary [n, k] Euclidean LCD MDS code, where \\\\(0\\\\le k \\\\le n\\\\le q+1\\\\), or, \\\\(q=2^{m}\\\\), \\\\(n=q+2\\\\) and \\\\(k= 3 \\\\text { or } q-1\\\\). Secondly, we investigate several constructions of new Euclidean and Hermitian LCD MDS codes. Our main techniques in constructing Euclidean and Hermitian LCD MDS codes use some linear codes with small dimension or codimension, self-orthogonal codes and generalized Reed-Solomon codes.\",\n \"Title: Componentwise APNness, Walsh uniformity of APN functions and cyclic-additive difference sets.\\nYear: 2018\\n\\nAbstract: In [Characterizations of the differential uniformity of vectorial functions by the Walsh transform, IEEE Transactions on Information Theory 2017], the author has characterized differentially δ-uniform functions by equalities satisfied by their Walsh transforms. This generalizes the characterization of APN functions by the fourth moment of the Walsh transform. We study two notions which are related: (1) the componentwise APNness (CAPNness) of (n,n)-functions, which is a stronger version of APNness, related to the characterization by the fourth moment, in which the arithmetic mean of WF4(u,v) when u ranges over F2n and v is fixed nonzero in F2n equals 22n+1 (2) the componentwise Walsh uniformity (CWU) of (n,m)-functions (m=n, resp. m=n−1), which is a stronger version of APNness (resp. of differential 4-uniformity) related to one of the new characterizations, in which the arithmetic mean of WF2(u1,v1)WF2(u2,v2)WF2(u1+u2,v1+v2) when u1,u2 range independently over F2n and v1,v2 are fixed nonzero and distinct in F2m, equals 23n. Concerning the first notion, it is known from Berger, Canteaut, Charpin and Laigle-Chapuy that any plateaued function is CAPN if and only if it is AB and that APN power permutations are CAPN. We prove that CAPN functions can exist only if n is odd; this solves an eleven year old open problem by these authors. Concerning the second notion, we show that any crooked function (and in particular any quadratic APN function) is CWU, but we observe also that other APN functions like Kasami functions and the inverse of one of the Gold APN permutations are CWU for n≤11. We show that the CWUness of APN power permutations is equivalent to a property of ΔF={F(x)+F(x+1)+1;x∈F2n}. This new property, that we call cyclic-additive difference set property, is more complex than the cyclic difference set property (proved in the case of Kasami APN functions by Dillon and Dobbertin). We prove it in the case of the inverse of Gold function. In the case of Kasami functions, we observe that the cyclic-additive property is also true for n≤10 even and we leave the proof of the CWUness and the cyclic-additive property as open problems.\",\n \"Title: Linear codes over Fq which are equivalent to LCD codes.\\nYear: 2017\\n\\nAbstract: Linear codes with complementary duals (abbreviated LCD) are linear codes whose intersection with their dual are trivial. When they are binary, they play an important role in armoring implementations against side-channel attacks and fault injection attacks. Non-binary LCD codes in characteristic 2 can be transformed into binary LCD codes by expansion. In this paper, we introduce a general construction of LCD codes from any linear codes. Further, we show that any linear code over $mathbb F_{q} (qu003e3)$ is equivalent to an Euclidean LCD code and any linear code over $mathbb F_{q^2} (qu003e2)$ is equivalent to a Hermitian LCD code. Consequently an $[n,k,d]$-linear Euclidean LCD code over $mathbb F_q$ with $qu003e3$ exists if there is an $[n,k,d]$-linear code over $mathbb F_q$ and an $[n,k,d]$-linear Hermitian LCD code over $mathbb F_{q^2}$ with $qu003e2$ exists if there is an $[n,k,d]$-linear code over $mathbb F_{q^2}$. Hence, when $qu003e3$ (resp.$qu003e2$) $q$-ary Euclidean (resp. $q^2$-ary Hermitian) LCD codes possess the same asymptotical bound as $q$-ary linear codes (resp. $q^2$-ary linear codes). Finally, we present an approach of constructing LCD codes by extending linear codes.\",\n \"Title: Stochastic Collision Attack.\\nYear: 2017\\n\\nAbstract: On the one hand, collision attacks have been introduced in the context of side-channel analysis for attackers who exploit repeated code with the same data without having any knowledge of the leakage model. On the other hand, stochastic attacks have been introduced to recover leakage models of internally processed intermediate secret variables. Both techniques have shown advantages and intrinsic li...\",\n \"Title: Trade-Offs for S-Boxes: Cryptographic Properties and Side-Channel Resilience.\\nYear: 2017\\n\\nAbstract: When discussing how to improve side-channel resilience of a cipher, an obvious direction is to use various masking or hiding countermeasures. However, such schemes come with a cost, e.g. an increase in the area and/or reduction of the speed. When considering lightweight cryptography and various constrained environments, the situation becomes even more difficult due to numerous implementation restrictions. However, some options are possible like using S-boxes that are easier to mask or (more on a fundamental level), using S-boxes that possess higher inherent side-channel resilience. In this paper we investigate what properties should an S-box possess in order to be more resilient against side-channel attacks. Moreover, we find certain connections between those properties and cryptographic properties like nonlinearity and differential uniformity. Finally, to strengthen our theoretical findings, we give an extensive experimental validation of our results.\",\n \"Title: Construction of Highly Nonlinear 1-Resilient Boolean Functions With Optimal Algebraic Immunity and Provably High Fast Algebraic Immunity.\\nYear: 2017\\n\\nAbstract: In 2013, Tang, Carlet, and Tang [IEEE TIT 59(1): 653-664, 2013] presented two classes of Boolean functions. The functions in the first class are unbalanced and the functions in the second one are balanced. Both of those two classes of functions have high nonlinearity, high algebraic degree, optimal algebraic immunity, and high fast algebraic immunity. However, they are not 1-resilient which repres...\",\n \"Title: New characterization and parametrization of LCD Codes.\\nYear: 2019\\n\\nAbstract: Linear complementary dual (LCD) cyclic codes were referred historically to as reversible cyclic codes, which had applications in data storage. Due to a newly discovered application in cryptography, there has been renewed interest in LCD codes. In particular, it has been shown that binary LCD codes play an important role in implementations against side-channel attacks and fault injection attacks. I...\",\n \"Title: Characterizations of o-polynomials by the Walsh transform.\\nYear: 2017\\n\\nAbstract: The notion of o-polynomial comes from finite projective geometry. In 2011 and later, it has been shown that those objects play an important role in symmetric cryptography and coding theory to design bent Boolean functions, bent vectorial Boolean functions, semi-bent functions and to construct good linear codes. In this note, we characterize o-polynomials by the Walsh transform of the associated vectorial functions.\",\n \"Title: A new concatenated type construction for LCD codes and isometry codes.\\nYear: 2018\\n\\nAbstract: We give a new concatenated type construction for linear codes with complementary dual (LCD) over small finite fields. In this construction,we need a special class of inner codes that we call isometry codes. Our construction generalizes a recent construction of Carlet et al. (2014–2016) and of Güneri et al. (2016). In particular, it allows us to construct LCD codes with improved parameters directly.\",\n \"Title: Classification of Bent Monomials, Constructions of Bent Multinomials and Upper Bounds on the Nonlinearity of Vectorial Functions.\\nYear: 2018\\n\\nAbstract: This paper is composed of two main parts related to the nonlinearity of vectorial functions. The first part is devoted to maximally nonlinear (n, m) functions (the so-called bent vectorial functions), which contribute to an optimal resistance to both linear and differential attacks on symmetric cryptosystems. They can be used in block ciphers at the cost of additional diffusion/compression/expansi...\",\n \"Title: Three basic questions on Boolean functions.\\nYear: 2017\\n\\nAbstract: In a first part of this paper, we investigate those Boolean functions satisfying two apparently related, but in fact distinct conditions concerning the algebraic degree: 1. we study those Boolean functions f whose restrictions to all affine hyper planes have the same algebraic degree (equal to deg(f), the algebraic degree of f), 2. we study those functions whose derivatives D-a f(x) = f(x) + f(x + a), a not equal 0, have all the same (optimal) algebraic degree deg(f) - 1. For determining to which extent these two questions are related, we find three classes of Boolean functions: the first class satisfies both conditions, the second class satisfies the first condition but not the second and the third class satisfies the second condition but not the first. We also give for any fixed positive integer k and for all integers n, p, s such that p >= k +1, s >= k + 1 and n >= ps, a class (denoted by C-n,C-p,C-s) of functions whose restrictions to all k-codimensional affine subspaces of F-2(n) have the same algebraic degree as the function. In a second part of the paper, we introduce the notion of second-order bent function, whose second order derivatives DaDb f(x) = f (x) + f(x + a) + f(x + b) + f(x + a + b), a not equal 0, b not equal 0, a not equal b, are all balanced. We exhibit an example in 3 variables and we prove that second-order-bent functions cannot exist if n is not congruent with 3 mod 4. We characterize second-order-bent functions by the Walsh transform, state some of their properties and prove the non existence of such functions for algebraic degree 3 when n > 3. We leave open the question whether second-order-bent functions can exist for n larger than 3.\",\n \"Title: On Upper Bounds for Algebraic Degrees of APN Functions.\\nYear: 2018\\n\\nAbstract: We study the problem of existence of APN functions of algebraic degree n over F2n. We characterize such functions by means of derivatives and power moments of the Walsh transform. We deduce several non-existence results which imply, in particular, that for most of the known APN functions F over F2n. the function x2n-1 + F(x) is not APN, and changing a value of F in a single point then results in n...\",\n \"Title: Statistical properties of side-channel and fault injection attacks using coding theory.\\nYear: 2018\\n\\nAbstract: Naïve implementation of block ciphers are subject to side-channel and fault injection attacks. To deceive side-channel attacks and to detect fault injection attacks, the designer inserts specially crafted error correcting codes in the implementation. The impact of codes on protection against fault injection attacks is well studied: the number of detected faults relates to their minimum distance. However, regarding side-channel attacks, the link between codes and protection efficiency is blurred. In this paper, we relate statistical properties of code-based countermeasures against side-channel attacks to their efficiency in terms of security, against uni- and multi-variate attacks.\",\n \"Title: Polynomial direct sum masking to protect against both SCA and FIA.\\nYear: 2018\\n\\nAbstract: Side-channel attacks (SCAs) and fault injection attacks (FIAs) allow an opponent to have partial access to the internal behavior of the hardware. Since the end of the 1990s, many works have shown that this type of attacks constitutes a serious threat to cryptosystems implemented in embedded devices. In the state of the art, there exist several countermeasures to protect symmetric encryption (especially AES-128). Most of them protect only against one of these two attacks (SCA or FIA). A method called ODSM has been proposed to withstand SCA and FIA, but its implementation in the whole algorithm is a big open problem when no particular hardware protection is possible. In the present paper, we propose a practical masking scheme specifying ODSM which makes it possible to protect the symmetric encryption against these two attacks.\",\n \"Title: Problems and solutions of the Fourth International Students' Olympiad in Cryptography NSUCRYPTO.\\nYear: 2018\\n\\nAbstract: Mathematical problems and their solutions from the fourth International Students' Olympiad in cryptography (NSUCRYPTO-2017) are presented. We consider problems related to attacks on ciphers and hash functions, cryptographic Boolean functions, linear branch numbers, addition chains, and error correction codes, among others. We discuss several open problems involving the algebraic structures of cryptographic functions, useful proof-of-work algorithms, the Boolean hidden shift problem, and quantum computing.\",\n \"Title: Two constructions of optimal pairs of linear codes for resisting side channel and fault injection attacks.\\nYear: 2018\\n\\nAbstract: Direct sum masking (DSM) has been proposed as a counter-measure against side-channel attacks (SCA) and fault injection attacks (FIA), which are nowadays important domains of cryptanalysis. DSM needs two linear codes whose sum is direct and equals a whole space $Bbb F_q^n$. The minimum distance of the former code and the dual distance of the latter should be as large as possible, given their length and dimensions. But the implementation needs in practice to work with words obtained by appending, to each codeword $y$ of the latter code, the source word from which $y$ is the encoding. Let $mathcal C_1$ be an $[n, k]$ linear code over the finite field $Bbb F_q$ with generator matrix $G$ and let $mathcal C_2$ be the linear code over the finite field $Bbb F_q$ with generator matrix $[G, I_k]$. It is then highly desired to construct optimal pairs of linear codes satisfying that $d(mathcal C_2^perp)= d(mathcal C_1^perp)$. In this paper, we employ the primitive irreducible cyclic codes to derive two constructions of optimal pairs of linear codes for resisting SCA and FIA, where the security parameters are determined explicitly. To the best of our knowledge, it is the first time that primitive irreducible cyclic codes are used to construct (optimal) pairs of codes. As a byproduct, we obtain the weight enumerators of the codes $mathcal C_1, mathcal C_2, mathcal C_1^perp$, and $mathcal C_2^perp$ in our both constructions.\",\n \"Title: On Linear Complementary Pairs of Codes.\\nYear: 2018\\n\\nAbstract: We study linear complementary pairs (LCP) of codes (C, D), where both codes belong to the same algebraic code family. We especially investigate constacyclic and quasicyclic LCP of codes. We obtain characterizations for LCP of constacyclic codes and LCP of quasi-cyclic codes. Our result for the constacyclic complementary pairs extends the characterization of linear complementary dual (LCD) cyclic c...\",\n \"Title: Constructing APN Functions Through Isotopic Shifts\\nYear: 2018\\n\\nAbstract: Almost perfect nonlinear (APN) functions over fields of characteristic 2 play an important role in cryptography, coding theory and, more generally, mathematics and information theory. In this paper we deduce a new method for constructing APN functions by studying the isotopic equivalence, concept defined for quadratic planar functions in fields of odd characteristic. In particular, we construct a family of quadratic APN functions which provides a new example of an APN mapping over F\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">29</sub>\\n and includes an example of another APN function x\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">9</sup>\\n + Tr(x\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n) over F\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">28</sub>\\n, known since 2006 and not classified up to now. We conjecture that the conditions for this family are satisfied by infinitely many APN functions.\",\n \"Title: Construction of Some Codes Suitable for Both Side Channel and Fault Injection Attacks.\\nYear: 2018\\n\\nAbstract: Using algebraic curves over finite fields, we construct some codes suitable for being used in the countermeasure called Direct Sum Masking which allows, when properly implemented, to protect the whole cryptographic block cipher algorithm against side channel attacks and fault injection attacks, simultaneously. These codes address a problem which has its own interest in coding theory.\",\n \"Title: On <inline-formula> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma$ </tex-math></inline-formula>-LCD Codes\\nYear: 2019\\n\\nAbstract: Linear complementary pairs (LCPs) of codes play an important role in armoring implementations against side-channel attacks and fault injection attacks. One of the most common ways to construct LCP of codes is to use Euclidean linear complementary dual (LCD) codes. In this paper, we first introduce the concept of linear codes with \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n complementary dual (\\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD), which includes known Euclidean LCD codes, Hermitian LCD codes, and Galois LCD codes. Like Euclidean LCD codes, \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD codes can also be used to construct LCP of codes. We show that for \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$q > 2$ </tex-math></inline-formula>\\n, all \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$q$ </tex-math></inline-formula>\\n-ary linear codes are \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD, and for every binary linear code \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\mathcal C$ </tex-math></inline-formula>\\n, the code \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\{0\\\\}\\\\times \\\\mathcal C$ </tex-math></inline-formula>\\n is \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD. Furthermore, we study deeply \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD generalized quasi-cyclic (GQC) codes. In particular, we provide the characterizations of \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD GQC codes, self-orthogonal GQC codes, and self-dual GQC codes, respectively. Moreover, we provide the constructions of asymptotically good \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD GQC codes. Finally, we focus on \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD abelian codes and prove that all abelian codes in a semi-simple group algebra are \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD. The results derived in this paper extend those on the classical LCD codes and show that \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\sigma $ </tex-math></inline-formula>\\n-LCD codes allow the construction of LCP of codes more easily and with more flexibility.\",\n \"Title: On APN exponents, characterizations of differentially uniform functions by the Walsh transform, and related cyclic-difference-set-like structures.\\nYear: 2019\\n\\nAbstract: In this paper, we summarize the results obtained recently in three papers on differentially uniform functions in characteristic 2, and presented at the workshop WCC 2017 in Saint-Petersburg, and we give new results on these functions. Firstly, we recall the recent connection between almost perfect nonlinear (APN) power functions and the two notions in additive combinatorics of Sidon sets and sum-free sets; we also recall a characterization of APN exponents which leads to a property of Dickson polynomials in characteristic 2 previously unobserved, which is generalizable to all finite fields. We also give a new characterization of APN exponents in odd dimension by Singer sets. Secondly, after recalling the recent multiple generalization to differentially \\\\(\\\\delta \\\\)-uniform functions of the Chabaud–Vaudenay characterization of APN functions by their Walsh transforms, we generalize the method to all criteria on vectorial functions dealing with the numbers of solutions of equations of the form \\\\(\\\\sum _{i\\\\in I}F(x+u_{i,a})+L_a(x)+u_a=0\\\\), with \\\\(L_a\\\\) linear; we give the examples of injective functions and of o-polynomials; we also deduce a generalization to differentially \\\\(\\\\delta \\\\)-uniform functions of the Nyberg characterization of APN functions by means of the Walsh transforms of their derivatives. Thirdly, we recall the two notions of componentwise APNness (CAPNness) and componentwise Walsh uniformity (CWU). We recall why CAPN functions can exist only if n is odd and why crooked functions (in particular, quadratic APN functions) are CWU. We also recall that the inverse of one of the Gold permutations is CWU and not the others. Another potential class of CWU functions is that of Kasami functions. We consider the difference sets with Singer parameters equal to the complement of \\\\(\\\\varDelta _F=\\\\{F(x)+F(x+1)+1; x\\\\in \\\\mathbb {F}_{2^n}\\\\}\\\\) where F is a Kasami function. These sets have another potential property, called the cyclic-additive difference set property, which is related to the CWU property in the case of power permutations (n odd). We study cyclic-additive difference sets among Singer sets. We recall the main properties of Kasami functions and of the related set \\\\(\\\\varDelta _F\\\\) shown by Dillon and Dobbertin and we observe and prove new expressions for \\\\(\\\\varDelta _F\\\\).\",\n \"Title: A New Representation of Boolean Functions\\nYear: 1999\\n\\nAbstract: We study a representation of Boolean functions (and more generally of integer-valued / complex-valued functions), not used until now in coding and cryptography, which yields more information than the currently known representations, on the combinatorial, spectral and cryptographic properties of the functions.\",\n \"Title: On immunity profile of boolean functions\\nYear: 2006\\n\\nAbstract: The notion of resilient function has been recently weakened to match more properly the features required for Boolean functions used in stream ciphers. We introduce and we study an alternate notion of almost resilient function. We show that it corresponds more closely to the requirements that make the cipher more resistant to precise attacks.\",\n \"Title: Binary Linear Codes From Vectorial Boolean Functions and Their Weight Distribution.\\nYear: 2017\\n\\nAbstract: Binary linear codes with good parameters have important applications in secret sharing schemes, authentication codes, association schemes, and consumer electronics and communications. In this paper, we construct several classes of binary linear codes from vectorial Boolean functions and determine their parameters, by further studying a generic construction developed by Ding et al. recently. First, by employing perfect nonlinear functions and almost bent functions, we obtain several classes of six-weight linear codes which contain the all-one codeword, and determine their weight distribution. Second, we investigate a subcode of any linear code mentioned above and consider its parameters. When the vectorial Boolean function is a perfect nonlinear function or a Gold function in odd dimension, we can completely determine the weight distribution of this subcode. Besides, our linear codes have larger dimensions than the ones by Ding et al.’s generic construction.\",\n \"Title: Characterizations of the differential uniformity of vectorial functions by the Walsh transform.\\nYear: 2018\\n\\nAbstract: For every positive integers n and m and every even positive integer δ, we derive inequalities satisfied by the Walsh transforms of all vectorial (n, m)-functions and prove that the case of equality characterizes differential δ-uniformity. This provides a generalization to all differentially δ-uniform functions of the characterization of Almost Perfect Nonlinear (APN) functions due to Chabaud and V...\",\n \"Title: Connecting and Improving Direct Sum Masking and Inner Product Masking.\\nYear: 2017\\n\\nAbstract: Direct Sum Masking (DSM) and Inner Product (IP) masking are two types of countermeasures that have been introduced as alternatives to simpler (e.g., additive) masking schemes to protect cryptographic implementations against side-channel analysis. In this paper, we first show that IP masking can be written as a particular case of DSM. We then analyze the improved security properties that these (more complex) encodings can provide over Boolean masking. For this purpose, we introduce a slight variation of the probing model, which allows us to provide a simple explanation to the “security order amplification” for such masking schemes that was put forward at CARDIS 2016. We then use our model to search for new instances of masking schemes that optimize this security order amplification. We finally discuss the relevance of this security order amplification (and its underlying assumption of linear leakages) based on an experimental case study.\",\n \"Title: On the Derivative Imbalance and Ambiguity of Functions.\\nYear: 2019\\n\\nAbstract: In 2007, Carlet and Ding introduced two parameters, denoted by $Nb_F$ and $NB_F$, quantifying respectively the balancedness of general functions $F$ between finite Abelian groups and the (global) balancedness of their derivatives $D_a F(x)=F(x+a)-F(x)$, $ain Gsetminus{0}$ (providing an indicator of the nonlinearity of the functions). These authors studied the properties and cryptographic significance of these two measures. They provided for S-boxes inequalities relating the nonlinearity $mathcal{NL}(F)$ to $NB_F$, and obtained in particular an upper bound on the nonlinearity which unifies Sidelnikov-Chabaud-Vaudenayu0027s bound and the covering radius bound. At the Workshop WCC 2009 and in its postproceedings in 2011, a further study of these parameters was made; in particular, the first parameter was applied to the functions $F+L$ where $L$ is affine, providing more nonlinearity parameters. In 2010, motivated by the study of Costas arrays, two parameters called ambiguity and deficiency were introduced by Panario emph{et al.} for permutations over finite Abelian groups to measure the injectivity and surjectivity of the derivatives respectively. These authors also studied some fundamental properties and cryptographic significance of these two measures. Further studies followed without that the second pair of parameters be compared to the first one. In the present paper, we observe that ambiguity is the same parameter as $NB_F$, up to additive and multiplicative constants (i.e. up to rescaling). We make the necessary work of comparison and unification of the results on $NB_F$, respectively on ambiguity, which have been obtained in the five papers devoted to these parameters. We generalize some known results to any Abelian groups and we more importantly derive many new results on these parameters.\",\n \"Title: The Fifth International Students' Olympiad in Cryptography - NSUCRYPTO: problems and their solutions.\\nYear: 2019\\n\\nAbstract: Problems and their solutions of the Fifth International Students? Olympiad in cryptography NSUCRYPTO?2018 are presented. We consider problems related to attacks on ciphers and hash functions, Boolean functions, quantum circuits, Enigma, etc. We discuss several open problems on orthogonal arrays, Sylvester matrices, and disjunct matrices. The problem of existing an invertible Sylvester matrix whose inverse is again a Sylvester matrix was completely solved during the Olympiad.\",\n \"Title: Detecting Faults In Inner Productmasking Scheme Ipm-Fd: Ipm With Fault Detection (Extended Version*)\\nYear: 2021\\n\\nAbstract: Side-channel analysis and fault injection attacks are two typical threats to cryptographic implementations, especially in modern embedded devices. Thus, there is an insistent demand for dual side-channel and fault injection protections. As we know, masking is a kind of provable countermeasure against side-channel attacks. Recently, inner product masking (IPM) was proposed as a promising higher-order masking scheme against side-channel analysis, but not for fault injection attacks. In this paper, we devise a new masking scheme named IPM-FD. It is built on IPM, which enables fault detection. This novel masking scheme has three properties: the security orders in the word-level probing model, bit-level probing model and the number of detected faults. IPM-FD is proven secure both in the word-level and in the bit-level probing models and allows for end-to-end fault detection against fault injection attacks. Furthermore, we illustrate its security order by interpreting IPM-FD as a coding problem and then linking it to one defining parameters of linear code and show its implementation cost by applying IPM-FD to AES-128.\",\n \"Title: Evolutionary algorithms-assisted construction of cryptographic boolean functions\\nYear: 2021\\n\\nAbstract: ABSTRACTIn the last few decades, evolutionary algorithms were successfully applied numerous times for creating Boolean functions with good cryptographic properties. Still, the applicability of such approaches was always limited as the cryptographic community knows how to construct suitable Boolean functions with deterministic algebraic constructions. Thus, evolutionary results so far helped to increase the confidence that evolutionary techniques have a role in cryptography, but at the same time, the results themselves were seldom used. This paper considers a novel problem using evolutionary algorithms to improve Boolean functions obtained through algebraic constructions. To this end, we consider a recent generalization of Hidden Weight Boolean Function construction, and we show that evolutionary algorithms can significantly improve the cryptographic properties of the functions. Our results show that the genetic algorithm performs by far the best of all the considered algorithms and improves the nonlinearity property in all Boolean function sizes. As there are no known algebraic techniques to reach the same goal, we consider this application a step forward in accepting evolutionary algorithms as a powerful tool in the cryptography domain.\",\n \"Title: Bounds on the Nonlinearity of Differentially Uniform Functions by Means of Their Image Set Size, and on Their Distance to Affine Functions\\nYear: 2021\\n\\nAbstract: We revisit and take a closer look at a (not so well known) result of a 2017 paper, showing that the differential uniformity of any vectorial function is bounded from below by an expression depending on the size of its image set. We make explicit the resulting tight lower bound on the image set size of differentially $\\\\delta $ ...\",\n \"Title: A Wide Class of Boolean Functions Generalizing the Hidden Weight Bit Function\\nYear: 2022\\n\\nAbstract: Designing Boolean functions whose output can be computed with light means at high speed, and satisfying all the criteria necessary to resist all major attacks on the stream ciphers using them as nonlinear components, has been an open problem since the beginning of this century, when algebraic attacks were invented. Functions allowing a good resistance are known since 2008, but their output is a li...\",\n \"Title: Evolving Constructions for Balanced, Highly Nonlinear Boolean Functions\\nYear: 2022\\n\\nAbstract: Finding balanced, highly nonlinear Boolean functions is a difficult problem where it is not known what nonlinearity values are possible to be reached in general. At the same time, evolutionary computation is successfully used to evolve specific Boolean function instances, but the approach cannot easily scale for larger Boolean function sizes. Indeed, while evolving smaller Boolean functions is almost trivial, larger sizes become increasingly difficult, and evolutionary algorithms perform suboptimally. In this work, we ask whether genetic programming (GP) can evolve constructions resulting in balanced Boolean functions with high nonlinearity. This question is especially interesting as there are only a few known such constructions. Our results show that GP can find constructions that generalize well, i.e., result in the required functions for multiple tested sizes. Further, we show that GP evolves many equivalent constructions under different syntactic representations. Interestingly, the simplest solution found by GP is a particular case of the well-known indirect sum construction.\",\n \"Title: A Complete Study of Two Classes of Boolean Functions: Direct Sums of Monomials and Threshold Functions\\nYear: 2022\\n\\nAbstract: In this paper, we make a comprehensive study of two classes of Boolean functions whose interest originally comes from hybrid symmetric-FHE encryption (with stream ciphers like FiLIP), but which also present much interest for general stream ciphers. The functions in these two classes are cheap and easy to implement, and they allow the resistance to all classical attacks and to their guess and deter...\"\n]","isConversational":false},"profile_size":{"kind":"number","value":132,"string":"132"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13360,"string":"13,360"}}},{"rowIdx":13361,"cells":{"question_id":{"kind":"string","value":"Yi Luo"},"question":{"kind":"string","value":"Generate an abstract for the title \"Multi-Task Medical Concept Normalization Using Multi-View Convolutional Neural Network.\" using the following items: 1. Medical concept normalization\n2. Normalizing diagnostic and procedure names \n3. Semantic matching problem \n4. Multi-task shared structure \n5. Comprehensive experimental analysis"},"answer":{"kind":"string","value":"Medical concept normalization is a critical problem in biomedical research and clinical applications. In this paper, we focus on normalizing diagnostic and procedure names in Chinese discharge summaries to standard entities, which is formulated as a semantic matching problem. However, non-standard Chinese expressions, short-text normalization and heterogeneity of tasks pose critical challenges in our problem. This paper presents a general framework which introduces a tensor generator and a novel multi-view convolutional neural network (CNN) with multi-task shared structure to tackle the two tasks simultaneously. We propose that the key to address non-standard expressions and short-text problem. is to incorporate a matching tensor with multiple granularities. Then multi-view CNN is adopted to extract semantic matching patterns and learn to synthesize them from different views. Finally, multi-task shared structure allows the model to exploit medical correlations between disease and procedure names to better perform disambiguation tasks. Comprehensive experimental analysis indicates our model outperforms existing baselines which demonstrates the effectiveness of our model."},"correct_answer":{"kind":"string","value":"Medical concept normalization is a critical problem in biomedical research and clinical applications. In this paper, we focus on normalizing diagnostic and procedure names in Chinese discharge summaries to standard entities, which is formulated as a semantic matching problem. However, non-standard Chinese expressions, short-text normalization and heterogeneity of tasks pose critical challenges in our problem. This paper presents a general framework which introduces a tensor generator and a novel multi-view convolutional neural network (CNN) with multi-task shared structure to tackle the two tasks simultaneously. We propose that the key to address non-standard expressions and short-text problem. is to incorporate a matching tensor with multiple granularities. Then multi-view CNN is adopted to extract semantic matching patterns and learn to synthesize them from different views. Finally, multi-task shared structure allows the model to exploit medical correlations between disease and procedure names to better perform disambiguation tasks. Comprehensive experimental analysis indicates our model outperforms existing baselines which demonstrates the effectiveness of our model."},"documents":{"kind":"list like","value":["Title: Insar deformation time series analysis using small-baseline approach\nYear: 2013\n\nAbstract: The crustal activities in Dangxiong basin are frequent and a great deal of geothermal energy is converged under the surface. The geothermic resources are used through the exploitation of underground water. Over-extraction of underground fluids causes the subsidence in the geothermal fields. We present the application of small-baseline InSAR time series method to monitor the land surface subsidence and spatial-temporal evolution in Yangbajing. Our data consists of 24 ASAR images acquired from ENVISAT satellite, spanning a time interval from Oct 2006 to Aug 2010. The results show that the maximum surface subsidence rate of the geothermal region is up to 15 mm/yr whilst subsidence rate in other fields is approximately 6 mm/yr.","Title: A Scalable and I/O Optimal Skyline Processing Algorithm\nYear: 2004\n\nAbstract: In this paper, we will present a novel progressive algorithm for computing skyline queries. The algorithm is based on the depth-first search paradigm. It can be shown that the new algorithm is I/O optimal. Further, we can show that the algorithm takes a logarithmic memory space in 2D-space in the worst case if there are not many intersections in an adopted R-tree. Our experiment demonstrated that the new algorithm is more scalable and efficient than the existing techniques especially in a low dimensional space. The experiment also showed that the algorithm is progressive in a way sensitive to a user's preference.","Title: A New Integration Method of Web-Based Video Monitoring System\nYear: 2013\n\nAbstract: This paper focuses on analysis of a nuclear power group to headquartered brand as the core, to surrounding radiation entire range of video monitoring system of distribution and the management current situation, according to the system's architecture features and user requirements, and based on the use of WPF and Web Service technology, it had proposed and constructed a new integration method and integration framework of unified integration, lightweight video monitoring management platform, to effectively solve the multi-region and multi-brand monitoring system of centralized management, unified authorized. And according to requires, it provide appropriate video service to other application system.","Title: Incorporating risk seeking attitude into defense strategy.\nYear: 2014\n\nAbstract: Optimal resource allocation is first found in defending possible targets against random terrorist attacks subject to budget constraint. The mathematical model is a nonconvex optimization problem which can be transformed into a convex problem by introducing new decision variables, so standard methods can be used for its solution. Without budget constraint the simplified model can be solved by a very simple algorithm which requires the solution of a single variable monotone equation.","Title: PS-InSAR time series analysis for measuring surface deformation before the L'Aquila earthquake\nYear: 2010\n\nAbstract: L'Aquila area has a high topography and complex geological structures, and is covered with thick vegetation and snow in areas of high topography. To monitor the characteristics of crustal deformation in this region before the 2009 L'Aquila earthquake, we apply StaMPS software to analyse 20 descending ASAR images acquired between September 2003 and March 2007 and 39 ascending ASAR images acquired between February 2003 and March 2009. In this paper, two mean LOS deformation velocity maps are acquired for this area, which reveal the same deformation pattern. Several deformation gradient in this area can be clearly identified, furthermore, we discover that most faults in this region may strike approximately NW-SE and dip <; 90° to SW. We also draw the conclusion that descending SAR images are superior to ascending ones in monitoring crustal deformation with InSAR in this region.","Title: FINE: A Fully Informed aNd Efficient Communication-Induced Checkpointing Protocol\nYear: 2008\n\nAbstract: In this paper, first we discuss two critical data structures used in the communication-induced checkpointing (CIC) protocols and their distinct roles in guaranteeing z- cycle free (ZCF) property by tracking the checkpoint and communication pattern (CCPAT) in a distributed computation that can lead to Z-cycles and preventing them. Then, we provide our Transitive Dependency Enabled TimeStamp (TDE_TSS) mechanism by which we can both timestamp each event and get the transitive dependency information upon receiving a message. Finally, based on this times- tamping mechanism, we present our Fully Informed aNd Efficient (FINE) checkpointing algorithm which can not only improve the performance of Fully Informed (FI) CIC protocol proposed by Helary et al. but also decrease the overhead of piggybacked information.","Title: Basis set dependence of solute-solvent interaction energy of benzene in water: a HF/DFT study.\nYear: 2008\n\nAbstract: Solute-solvent interaction energies for the benzene molecule dissolved in water are computed using Hartree-Fock and B3LYP density functional theories. Explicit solvent molecules up to 14-angstrom away from the dissolved benzene molecule are included in the calculation of interaction energies. Both basis set dependence and basis Set Superposition errors are carefully examined. It is found that the use of a larger basis set for the region near the solute together with a smaller basis set for the outer region gives results very close to what would have been obtained if the larger basis set had been used for the whole system. It is also shown that a correction for the basis Set superposition error is a necessary component in this kind of calculations. With this correction, results obtained with different tested basis sets converge to within 1 kcal/mol. (c) 2008 Wiley Periodicals, Inc.","Title: Children in the forest: towards a canonical problem of spatio-temporal collaboration\nYear: 2007\n\nAbstract: Canonical problems are simplified representations of a class of real world problems. They allow researchers to compare algorithms in a standard setting which captures the most important challenges of the real world problems being modeled. Such examples are the block world for planning, two-player games for algorithms which learn the behavior of the opponent agent, or the \"split the pie\" game for a large class of negotiation problems. In this paper we focus on negotiating collaboration in space and time, a problem with many important real world applications. Although technically a multi-issue negotiation, we show that the problem can not be represented in a satisfactory manner by the split the pie model. We propose the \"children in the rectangular forest\" (CRF) model as a possible canonical problem for negotiating spatio-temporal collaboration. By exploring a centralized and a peer-to-peer negotiation based solution, we demonstrate that the problem captures the main challenges of the real world problems while allows us to simplify away some of the computationally demanding but semantically marginal features of real world problems.","Title: Semantics Based Conformance Assessment of ebXML Business Processes\nYear: 2004\n\nAbstract: In the business world, the acceptance of a contract often lies beyond the agreement on price and quality of products. The conformance of respective business processes plays a significant role in the collaboration of business partners. Today, e-commerce standards such as ebXML have enabled enterprises to collaborate in the business process level. However, there is little work on the study of conformance assessment (also called matchmaking in some works) of business processes. Moreover, these e-commerce standards are syntactic rather than semantic, in which semantic constraints on interactions are represented informally. In this paper, we extend the ebXML specifications to support the semantics based conformance assessment of business processes, which transforms XML into RDF via the Semantic Web technology. The conformance criteria are mapped to OWL. The semantics based conformance criteria are defined. Furthermore, we extend the ebXML architecture by adding a conformance assessment agent to support the conformance assessment of business processes when searching the potential business partners. With its help, appropriate business partners can be discovered for the client as desired.","Title: New acoustic monitoring method using cross-correlation of primary frequency spectrum.\nYear: 2013\n\nAbstract: The acoustic data remotely measured by microphones are widely used to investigate monitoring and diagnose integrity of ball bearing in rotational machines. Early fault diagnosis is very difficult for acoustic emission. We propose a new method using a cross-correlation of frequency spectrum to classify various faults with fine grit. Principal component analysis (PCA) is used to separate the primary frequency spectrum into main frequency and residual frequency. Different with conventional classification using the PCA eigenvalue, we introduce the general cross-correlation (GCC) of main frequency and residual frequency spectrums between a basic signal vector and monitoring signal. Multi-classification strategy based on binary-tree support vector machine (SVM) is applied to perform faults diagnosis. In order to remove noise interference and increase robustness, a normalization method is proposed during time generation. Experiment results show that PCA-GCC-SVM method is able to diagnose various faults with high sensitivity. © 2012 Springer-Verlag.","Title: Error Propagation Analysis in Three-Dimensional Coseismic Displacement Inversion\nYear: 2014\n\nAbstract: Using the Bam earthquake as an example, we apply the multiple-aperture interferometry (MAI) algorithm to measure the azimuth (AZI) displacement with multiple mode synthetic aperture radar (SAR) images (ScanSAR and image modes) and further on produce the 3-D coseismic displacement maps using well-known models: multiple independent interferometric SAR (InSAR) with different viewing angles and combining MAI with conventional InSAR. The 3-D displacement maps show that, besides accuracy of SAR observation, inversion model is another major perturbing factor limiting the accuracy of 3-D component reconstruction. That is, in the former model, the smaller the difference of incidence angles is, the more easily influenced by ill-conditioned systems the estimated parameters are. Based on characteristics of error sources of SAR observations, we classify observation errors into random error, systematic error, and gross error. Moreover, their characteristics of error propagation are analyzed in the two models, respectively. Error propagation analysis indicates that random errors only affect variability of inversion result, while systematic error and gross error cause not only variability but also bias or uncertainty in estimated parameters. The presented error analysis method provides a more comprehensive understanding of bias or uncertainty of 3-D estimated components, which will be a useful tool for evaluating errors in displacement fields obtained from SAR observations. In this letter, we also group multiple InSAR and MAI observations to estimate 3-D components using weighted least squares whose weights are given by the Förstner posterior variance estimation, which may avoid an ill-conditioned system, reducing line-of-sight and AZI random noises and improving accuracies of estimated 3-D components.","Title: Multi-Level Intrusion Detection System (ML-IDS)\nYear: 2008\n\nAbstract: As the deployment of network-centric systems increases, network attacks are proportionally increasing in intensity as well as complexity. Attack detection techniques can be broadly classified as being signature-based, classification-based, or anomaly-based. In this paper we present a multi level intrusion detection system (ML-IDS) that uses autonomic computing to automate the control and management of ML-IDS. This automation allows ML-IDS to detect network attacks and proactively protect against them. ML-IDS inspects and analyzes network traffic using three levels of granularities (traffic flow, packet header, and payload), and employs an efficient fusion decision algorithm to improve the overall detection rate and minimize the occurrence of false alarms. We have individually evaluated each of our approaches against a wide range of network attacks, and then compared the results of these approaches with the results of the combined decision fusion algorithm.","Title: Research on Application and RF EMC of Bidirectional Wireless Communication System in Nuclear Power Plant\nYear: 2011\n\nAbstract: The wireless communication means is necessary for routine work and emergency operating in nuclear power station. With the developments of wireless technical and nuclear power plant, wireless communication system requires more comprehensive and widespread application. The secure and stable bidirectional wireless communication system is to have an important status in plant communication systems. In certain regions of nuclear power plant, such as nuclear island, RF emitting equipments have requirements to their electromagnetic compatibility, which should confirm to certain standards, to guarantee the operation of safety-related systems and the wireless communication system itself.","Title: Relation between Boolean operators and Euler operators\nYear: 1993\n\nAbstract: CSG [RET178] and B-rep [BAU72, BR473] are two widely-applied approaches for modelling solids. CSG approach is based on the theory of point set topology, using Boolean operations on primitive “building blocks” to obtain more complicated solid models. However, general Boolean operations based on naive set theory can cause dimension inconsistency and therefore are not closed to pure 3-D objects. To solve the problem, the concepts of regular sets and regularized Boolean operations has been introduced in [RET178] and have been an important contribution to the theory of point set topology, which made the theory being more suitable as the foundation of CSG approach of solid modeling technique.","Title: An enhanced model-based checkpointing protocol\nYear: 2007\n\nAbstract: Checkpointing and rollback recovery are widely used techniques to handle failures in distributed computing systems. Usually we avoid taking checkpoints that are useless during the recovery process. Communication-Induced checkpointing algorithms guarantee the usefulness of all the checkpoints and provide considerable autonomy with relatively low overhead. In this paper, we propose an enhanced Communication-Induced checkpointing algorithm. Our algorithm is likely to have less checkpointing overhead than an existing algorithm in the literature.","Title: Enhancing CMOS Using Nanoelectronic Devices: A Perspective on Hybrid Integrated Systems.\nYear: 2010\n\nAbstract: In this paper, we present a vision for the cointegration of deeply scaled complementary metal-oxide-semiconductor (CMOS) and emerging nanoelectronic devices into CMOS-hybrid systems. These hybrid systems will create new functionality, modality and add value to existing CMOS integrated circuits. We describe several new nanoelectronic devices which may enable new dimensions to traditional CMOS circu...","Title: Analyzing and exploiting the competitiveness of scenarios for negotiating convoy formation under time constraints\nYear: 2010\n\nAbstract: In the convoy formation problem, two embodied agents are negotiating the synchronization of their movement for a portion of the path from their respective sources to destinations. As equilibrium strategies are not practically possible, we are interested in strategies with bounded rationality, which achieve good performance in a wide range of practical negotiation scenarios. Naturally, the performance of a strategy is dependent on the strategy of the opponent and the characteristics of the scenario. The goal of this paper is to develop a collaborativeness metric of the negotiation scenario which formalizes our intuition of collaborative scenarios (where the agents' interests are closely aligned) versus competitive scenarios (where the gain of the utility for one agent is paid off with a loss of utility for the other agent). We are using the Children in the Rectangular Forest (CRF) game as a canonical model of convoy formation, assume zero initial knowledge and a negotiation protocol requiring mandatory, but non-binding evaluations of the opponents offer. We also assume that the negotiation happens in physical time. We describe two negotiation strategies: the comparatively simple Internal Negotiation Deadline (IND) strategy and the computationally more expensive Uniform Concession (UC) strategy. Then, we describe how these strategies can be augmented by collaborativeness analysis: we approximate the collaborativeness metric in the first several negotiation rounds, and use the result to cut short the negotiation when the estimated collaborativeness is lower than a threshold. Through an experimental study, we show that augmenting the strategies with collaborativeness analysis significantly improves their performance for low collaborativeness scenarios, with only a minimal penalty in high collaborativeness scenarios.","Title: Quantitative Evaluation of Human-Reliability Based on Fuzzy-Clonal Selection\nYear: 2011\n\nAbstract: Human reliability analysis (HRA) is necessary for system safety assessment as well as equipment reliability analysis. The cognitive reliability and error analysis method (CREAM) as a representative HRA method provides nine common performance conditions (CPCs) to represent the contextual conditions under which a given action is performed. With a scarcity of empirical data, a high uncertainty in analyzing results is produced by subjective judgment. To obtain more objective and effective HRA results, this paper presents an optimized quantification method to evaluate the human error probability (HEP) according to CREAM, and its linguistic variables. The starting point for the quantification is an introduced fuzzy version of CREAM. However, many fuzzy rules are redundant, and occupy extensive computing time. The clonal selection algorithm combined with the fuzzy model is proposed to optimize the rule set. The evaluation method using the fuzzy-clonal selection algorithm is aimed to support possible applications for prospective and retrospective studies in the domain of safety assessment of power systems. The simulations are carried out on four presumed contexts, and a practical power system. The conclusions illuminate the feasibility of the proposed quantitative method.","Title: Recommendation of More Interests Based on Collaborative Filtering\nYear: 2012\n\nAbstract: Collaborative Filtering is one of the most important techniques in recommender systems. Current researches on Collaborative Filtering focus on how to improve the accuracy. However, it is of the same importance to recommend more potential interests to users because many of them have more expectations for recommendation list besides the accuracy. Current recommender systems did not address this problem. This paper focuses on how to help users find more interests in the recommendation list. We propose an sampling-based algorithm Probabilistic Top-N Selection to recommend potential interests for users, and propose two metrics, average predicted rating and category coverage, to assess the quality of the recommendation list. Then we conduct a series of experiments on Movie Lens dataset, experimental results demonstrate that our algorithm can significantly improve user experience through providing them with more potential interests.","Title: An Optimal Divide-Conquer Algorithm for 2D Skyline Queries\nYear: 2003\n\nAbstract: Skyline query processing is fundamental to many applications including multi-criteria decision making. In this paper, we will present an optimal algorithm for computing skyline in the two dimensional space. The algorithm has the progressive nature and adopts the divide-conquer paradigm. It can be shown that our algorithm achieves the minimum I/O costs, and is more efficient and scalable than the existing techniques. The experiment results demonstrated that our algorithm greatly improves the performance of the existing techniques.","Title: Vision-Based Assembly Of Capillary For Microfluidic Device\nYear: 2006\n\nAbstract: The application of plastic microfluidic chips can be extended with quartz capillaries connected at the end of their microchannels, e.g. UV absorption detection method can be carried out, which responds to almost 80% chemical compounds in detection. A vision-based experiment system for automatically assembling capillaries to plastic microfluidic chips was set up. UN-curing adhesive is used for the joining procedure. Visual feedback is implemented in the assembly system and the control algorithm is briefly introduced. The methods for obtaining the spatial position deviation between the capillary and the end of the chip's micro channel are described. The deviation information in x-y plane is obtained by performing image processing and converting pixels into actual distance with calibrated data. Two methods for recovering vertical deviation information were explored, and both are feasible for application, one is the depth-in-focus, the other is with the use of microscopic stereovision.","Title: Theoretical and experimental evaluation of communication-induced checkpointing protocols in FE and FLazy-E families\nYear: 2011\n\nAbstract: Communication-induced checkpointing (CIC) protocols help in bounding rollback propagation by ensuring that each checkpoint taken is useful, while at the same time allowing each process to take checkpoints independently. In this paper, we focus on the evaluation of CIC protocols belonging to two families, namely, the F\"E family and F\"L\"a\"z\"y\"-\"E family. We present both theoretical and experimental evaluation of the protocols belonging to these two families. The results of our experimental evaluation not only confirm the theoretical comparison but also reveals the fine differences between these protocols.","Title: A light-weighted approach to workflow view implementation\nYear: 2006\n\nAbstract: Interaction is the central concern of the B2B E-commerce today. The concept of workflow views provides a convenient interface for advanced business transactions across enterprise boundaries. However, until now there is little work discussing the implementation issue of workflow views. In this paper, we present a light-weighted implementation model for workflow views, which advocates an easy-to-deploy approach to implement workflow view functions based on existing WFMSs without breaking their integrity. Via this approach, enterprises can equip their workflow systems with the versatile workflow views in an efficient and economical way.","Title: Cross-axis sensitivity enhancement for a quad beam piezoresistive accelerometer\nYear: 2013\n\nAbstract: MEMS based piezoresistive accelerometers have been used in wide range of industrial applications after decades of development. For future improvement, how to continuously reduce the cross-axis sensitivity to achieve higher main-axis precision is one of the most critical issues. This letter presents a new concept of structure design to deal with cross-axis sensitivity reduction for quad beam piezoresistive accelerometers. By using existed design with combination of new structure component, the spring constant increased and the cross axis sensitivity reduced to 0.22% of the primary axis sensitivity. Instead of using traditional fabrication process, some special designed methods and procedures are proposed to perform the structure shaping and the component combination.","Title: Application and improvement discussion about Apriori algorithm of association rules mining in cases mining of influenza treated by contemporary famous old Chinese medicine\nYear: 2012\n\nAbstract: Objective: To investigate and discuss the application and improvement about Apriori algorithm of association rules mining (ARM) in cases mining of influenza treated by contemporary famous old Chinese medicine. Methods: We analyzed the basic principles, processes and algorithms about the Apriori algorithm of ARM, then applied this algorithm to the cases mining of influenza treated by contemporary famous old Chinese medicine. SPSS Clementinel2.0 statistical software was used to mine the association rules between Etiology and traditional Chinese medicine (TCM), Syndromes and TCM, Symptoms and TCM. Then the disadvantage of the algorithm was summarized, and several improved high efficiency algorithms were discussed. Results: The Apriori algorithm of ARM could extract the association rules between common Etiology (Evil of wind, cold, heat and fire) and TCM, Syndromes (Syndromes of wind-heat or wind-cold invading exterior) and TCM, Symptoms (chills, fever, cough, nasal congestion, runny nose) and TCM. However, it became inefficient when the sample was large. Therefore, it was necessary to search for an improved Apriori algorithm in order to enhance the efficiency of ARM of Chinese medicine cases. Conclusion: The classic Apriori algorithm is useful to mine cases of influenza treated by contemporary famous old Chinese medicine, and the improved Apriori algorithm may help to improve the efficiency of mining.","Title: Application of data mining technology in excavating prevention and treatment experience of infectious diseases from famous herbalist doctors\nYear: 2011\n\nAbstract: This study is to explore effect and significance of data mining technology (DMT) used in excavating prevention and treatment experience of infectious diseases from famous herbalist doctors (FHDs). DMT methods such as cluster analysis and association rules was applied to the study on FHDs literature on preventing and treating influenza, dysentery, tuberculosis, viral hepatitis and other infectious diseases in order to excavate the inner rules and refine the regular understanding. The result shows that cluster analysis is helpful to summarize the common understanding of experience including concept of syndrome differentiation, regulation of diagnosis and treatment, prescription characteristic, which based on FHDs' prevention and treatment of influenza (including A H1N1), viral hepatitis and other infectious diseases. Association rules greatly contributed to the judgment of relationship between etiology, syndrome, symptoms and herbal prescription of infectious diseases. In conclusion, DMT provides technical support for concise and inheritance of academic thought which originates from FHDs. DMT is of high application value in research of experience of FHDs and relevant literature, and is worth further discussion.","Title: The loophole of the improved secure quantum sealed-bid auction with post-confirmation and solution\nYear: 2013\n\nAbstract: In the literature He et al. (Quantum Inf Process, 2011) performed the cryptanalysis about the protocol of secure quantum auction with post-confirmation, and proposed the melioration algorithm in order to defeat the collusion among some malicious bidders in Zhao et al.'s protocol (Zhao et al. in Opt Commun 283:3194, 2010). But unfortunately, this protocol can't defeat the collusion among some malicious bidders either. In this paper, we will analyze the security of He et al.'s protocol and point out the potential loophole. Furthermore, we propose an improved protocol which can defeat the collusion among malicious bidders effectively.","Title: An efficient first-principle approach for electronic structures calculations of nanomaterials.\nYear: 2008\n\nAbstract: An efficient parallel implementation has been realized for a recently proposed central insertion scheme (Jiang, Liu, Lu, Luo. J Chem Phys 2006,124,214711; J Chem Phys 2006,125, 149902) that allows to calculate electronic structures of nanomaterials at various density functional theory levels. It has adopted the sparse-matrix format for Fock/Kohn-Sham and overlap matrices, as well as a combination of implicitly restarted Arnoldi methods (IRAM) and spectral transformation for computing selected eigenvalues/eigenvectors. A systematic error analysis and control for the proposed method has been provided based on a strict mathematical basis. The efficiency and applicability of the new implementation have been demonstrated by calculations of electronic structures of two different nanomaterials consisting of one hundred thousand electrons.","Title: Accurate bond dissociation enthalpies by using doubly hybrid XYG3 functional.\nYear: 2011\n\nAbstract: In this work, we examine the performance of XYG3, a newly developed doubly hybrid density functional (Zhang, Xu, and Goddard III, Proc Natl Acad Sci USA 2009, 106, 4963), to calculate covalent bond dissociation enthalpy (BDE). We use 5 atoms, 32 molecular radicals, and 116 closed-shell molecules to set up 142 bond dissociation reactions. For the total of 148 heats of formation (HOFs) and 142 BDEs, XYG3 leads to mean absolute deviations (MADs) of 1.45 and 1.87 kcal/mol, respectively. In comparison with some other functionals, MADs for HOFs are 2.31 (M06-2X), 2.98 (B2PLYP-D), 3.04 (BMK), 3.96 (B3LYP), 4.47 (B2PLYP), 5.42 (B2GP-PLYP), 6.46 (PBE0), and 29.93 kcal/mol (B3P86), and the corresponding errors for BDEs are 2.06 (M06-2X), 2.25 (BMK), 2.51 (B2PLYP-D), 2.89 (B2GP-PLYP), 3.30 (B3P86), 3.44 (B2PLYP), 3.87 (PBE0), and 6.14 kcal/mol (B3LYP). (C) 2011 Wiley Periodicals, Inc. J Comput Chem 32: 1824-1838, 2011","Title: Human identification using correlation metrics of iris images\nYear: 2005\n\nAbstract: This paper presents work done based on second order statistical features including cross- and auto-correlations as well as co-occurrence matrices of iris images in an attempt to extract a simple, yet powerful, set of features of an iris as a biometric. Prior to our work, the most prevalent methods for iris identification include the frontier work based on the use of quadrature 2-D Gabor wavelets with the Hamming Distance-based classification [1,2], circular Gabor filters with a nearest feature line (NFL) classifier [3], dyadic wavelet transform with the zero-cross detectors [4], texture analysis [9] and transient signal [11], and independent component analysis (ICA) [7], and boundary localization [10]. Our method differs significantly from the earlier approaches to iris recognition in that it relies on the wide-sense stationary approximation to the texture and gray-level characteristics of irises, and aims to lend itself for a single-chip hardware implementation. Our preliminary results show that cross- and auto-correlators along with co-occurrence matrix features are highly likely to be prominent iris discriminators.","Title: Performance analysis of ad hoc networks with interference alignment\nYear: 2012\n\nAbstract: The performance of ad hoc networks is fundamentally limited by interference, especially by the interference from nearby transmitting nodes. In this work, we introduce vector space interference alignment (IA) to an ad hoc network scenario to efficiently eliminate interference. However, according to its feasibility conditions, vector space IA is impractical to implement in dense ad hoc networks directly. Therefore, we define an IA range to divide the ad hoc network into smaller local networks. The interference induced by the transmitters located in the pre-specified IA range is completely aligned and eliminated via an IA approach. Considering the effect of the interference from the transmitters located outside the IA range, the upper and lower bounds of outage probability and transmission capacity are characterized. Monte Carlo simulation results have validated the performance improvement provided by the proposed IA scheme in ad hoc networks.","Title: Reversible image water marking based on prediction-error expansion and compensation\nYear: 2011\n\nAbstract: Prediction-error expansion (PEE) develops Tian's difference expansion technique by performing reversible data embedding in the prediction-error histogram. As the prediction accuracy greatly affects the embedding performance, the PEE-based algorithms depend heavily on image's spatial redundancy. However, one drawback of these algorithms is that the modification of pixels may distort the high correlation in their local regions, and thus affect the prediction accuracy. To deal with this problem, we propose an adjustment process named \"compensation\" to compensate for the already modified pixels, before using them for prediction. Combining PEE and compensation together, a new reversible image watermarking algorithm is then presented. Comparisons with state-of-the-art works indicate that the compensation technique may benefit reversible watermarking in term of capacity-distortion behavior.","Title: Integration of multiple heterogeneous databases in Smalltalk\nYear: 2005\n\nAbstract: Providing integrated access to multiple, distributed, heterogeneous databases has become very important. Smalltalk can be used to achieve such an objectivity since Smalltalk can provide tools to connect commercial databases like Oracle and Sybase. We also developed tools to connect open source databases like Post-greSQL. Using these tools, data from multiple heterogenous databases can be extracted and mapped into objects in Smalltalk, where their syntactical and semantical conflicts can be resolved by object deputy model. An object deputy language is designed based on object deputy algebra and its compiler has been implemented in Smalltalk. In order to facilitate the use of object deputy language for data integration, we implemented an object deputy browser in Smalltalk.","Title: TCM syndromes diagnostic model of hypertension: Study based on Tree Augmented Naive Bayes\nYear: 2011\n\nAbstract: To establish a Bayesian diagnosis model of TCM symptoms by using the hypertension epidemiological Syndrome databases. The Clementine 12.0 software is used to build the Tree Augmented Naive Bayes models, calculate the Bayesian conditional probability, and compare the forecast accuracy of the syndrome diagnosis model. The training sample had 384 cases and calculated 69 symptoms and signs, without prior knowledge, the prediction accuracy rate of the training model are 72.11%, and with the prior knowledge, the testing sample had 384 cases, the prediction accuracy rate of testing model is up to 78.55%. Through the sample study, Bayesian networks can improve the prediction accuracy; we can build a more accurate hypertension diagnosis model through the current work.","Title: SPARK: A Keyword Search Engine on Relational Databases\nYear: 2008\n\nAbstract: Relational database is the most widely adopted and mature technology for information storage. As many services on the Web (e.g., blog and wiki sites) and advanced applications (e.g., customer relationship management systems and content management systems) are built on RDBMSs, increasing amount of text data is now stored in relational databases, accompanied by increasing demands of retrieving relevant information by free-style keyword search.","Title: Improved DE-based reversible watermarking using sorting and histogram shifting\nYear: 2010\n\nAbstract: In this paper, we present a revised reversible watermarking scheme based on the following techniques: difference expansion, sorting, and histogram shifting. The scheme emphasizes on low distortion with appointed capacity. Experimental results show that this novel algorithm keeps high PSNR with required payload, and its performance is better than some state-of-the-art algorithms.","Title: Deputy mechanism for workflow views\nYear: 2005\n\nAbstract: Adapted from the concept of views in databases, workflow views are derived from workflows as a fundamental support for workflow inter-operability and visibility by external parties in a e-service environment. However, until now there are few works focusing on its realization mechanism, i.e. the communication between views and their source entities. In this paper, we extend the object deputy model to the workflow deputy model supporting the interaction of workflow views in a systematic way. In this workflow deputy model, we formally specify the deputy class and the deputy algebra for workflow classes. According to the process meta-model of XPDL, deputy operations are defined for each kind of workflow component class specifically. Based on this deputy mechanism, workflow views are presented in forms of deputy classes. Lastly, several modeling issues are discussed.","Title: A model for evaluating QoE of mobile Internet services\nYear: 2012\n\nAbstract: In recent years, with the increasingly intense competition in mobile Internet services, both network operators and application developers pay more and more attention to Quality of Experience (QoE). However, there is no universal QoE evaluation model and method for mobile Internet services. In this paper, we propose a universal QoE model and evaluation method for mobile Internet services from a mobile application perspective. The QoE value obtained through our model is the overall subjective feelings of end-users for a mobile application in specific network, instead of simple “Excellent” or “Good”.","Title: Achieving Subpixel Georeferencing Accuracy in the Canadian AVHRR Processing System\nYear: 2010\n\nAbstract: Precise geolocation is one of the fundamental requirements for satellite imagery to be suitable for climate applications. The Global Climate Observing System and the Committee on Earth Observing Satellites identified the requirement for the accuracy of geolocation of satellite data for climate applications as 1/3 field of view (FOV). This requirement for the series of the Advanced Very High Resolu...","Title: Context-aware HCI service selection\nYear: 2012\n\nAbstract: Context-awareness has become a key issue in Human-Computer InteractionHCI to provide better user experience under multi-device and multi-modal environment. With this intuition, we have proposed a web service based framework, which associates interactions with services, and provided service selection mechanism using context knowledge to achieve smart interaction migration [1]. A fundamental problem of such a service-oriented framework for interaction migration is to design an effective while scalable algorithm for service selection. In this paper, we propose a service selection algorithm considering not only context information and user preferences but also inter-service relations such as relative location. Our algorithm detects interaction hot spots within user active scope and presents the best service combination based on evaluation of interaction effectiveness. We also conduct simulation and the results illustrate that our algorithm is effective and scalable for interaction service selection.","Title: FINE: A Fully Informed aNd Efficient communication-induced checkpointing protocol for distributed systems\nYear: 2009\n\nAbstract: Communication-Induced Checkpointing (CIC) protocols are classified into two categories in the literature: Index-based and Model-based. In this paper, we discuss two data structures being used in these two kinds of CIC protocols, and their different roles in helping the checkpointing algorithms to enforce Z-cycle Free (ZCF) property. Then, we present our Fully Informed aNd Efficient (FINE) communication-induced checkpointing algorithm, which not only has less checkpointing overhead than the well-known Fully Informed (FI) CIC protocol proposed by Helary et al. but also has less message overhead. Performance evaluation indicates that our protocol performs better than many of the other existing CIC protocols.","Title: Precoding design using interference alignment for the network MIMO\nYear: 2009\n\nAbstract: In this paper, an interference alignment system for the MIMO network is investigated. Three different precoding schemes, which are based on zero-forcing (ZF), minimum mean square error (MMSE) and maximum SLR criteria, are proposed. The simulation results show that the proposed precoding schemes are very efficient and can provide good performance for the considered MIMO network.","Title: A boundary representation for form features and non-manifold solid objects\nYear: 1991\n\nAbstract: A boundary scheme derived from the con- cept of cell decomposition is presented for modelling form features. \"Wedges\" and \"bundles\" are added to the data structure for handling non-manifold edges and vertices in the same way as handling multiply connected faces with loops. With a feature-based and ajoint-based llttler-Poincar6 formulae, feature operators and joint op- erators are determined for manipulating the data struc- ture which can explicitly represent both features and the joints between them and, at the same time, keep the topological adjacency relationships of the complete solid boundary. The properties of Euler operators are also discussed.","Title: HOPE: A Hybrid Optimistic checkpointing and selective Pessimistic mEssage logging protocol for large scale distributed systems\nYear: 2012\n\nAbstract: Future generation supercomputers will be message-passing distributed systems consisting of hundreds of thousands of processors. As the size of the system grows, failure rate increases. Hence for the success and deployability of such large scale systems, scalable checkpointing and recovery protocols need to be implemented. Existing checkpointing and rollback recovery protocols used for providing fault tolerance in distributed systems are not scalable to such large systems. In this paper, we address this important and timely issue and propose a scalable group-based Hybrid Optimistic checkpointing and selective Pessimistic mEssage logging (HOPE) protocol. Performance evaluation indicates, our protocol takes a balanced approach to lower checkpointing and message logging overhead and enhances scalability.","Title: Linear Decision Fusion Under The Control Of Constrained Pso For Wsns\nYear: 2012\n\nAbstract: A major application of a distributed WSN (wireless sensor network) is to monitor a specific area for detecting some events such as disasters and enemies. In order to achieve this objective, each sensor in the network is required to collect local observations which are probably corrupted by noise, make a local decision regarding the presence or absence of an event, and then send its local decision to a fusion center. After that, the fusion center makes the final decision depending on these local decisions and a decision fusion rule, so an efficient decision fusion rule is extremely critical. It is obvious that the decision-making capability of each node is different owing to the dissimilar signal noise ratios and some other factors, so it is easy to understand that a specific sensor contribution to the global decision should be constrained by this sensor decision-making capability, and, based on this idea, we establish a novel linear decision fusion model for WSNs. Moreover, the constrained particle swarm optimization (constrained PSO) algorithm is creatively employed to control the parameters of this model in this paper and we also apply the typical penalty function to solve the constrained PSO problem. The emulation results indicate that our design is capable of achieving very high accuracy.","Title: Locating steganographic payload for LSB matching embedding\nYear: 2011\n\nAbstract: Many highly sensitive detectors for least significant bit (LSB) matching steganography have been proposed so far, but few of them can locate the embedding payload. Assuming a number of stego images with payload placed in the same locations are provided, Ker presented a residual-based method to identify the payload-carrying locations for LSB matching. In this paper, we put forward two novel residuals and theoretically prove their reliability for LSB matching detection. Experimental results show that the proposed weighted l1 and l2 residuals significantly outperform the previous work in terms of both detection performance and computational complexity. Even very small payload can be perfectly detected and precisely located as long as adequate stego images are available.","Title: An improved co-evolution genetic algorithm for combinatorial optimization problems\nYear: 2011\n\nAbstract: This paper presents an improved co-evolution genetic algorithm (ICGA), which uses the methodology of game theory to solve the mode deception and premature convergence problem. In ICGA, groups become different players in the game. Mutation operator is designed to simulate the situation in the evolutionary stable strategy. Information transfer mode is added to ICGA to provide greater decision-making space. ICGA is used to solve large-scale deceptive problems and an optimal control problem. Results of numerical tests validate the algorithm's excellent performance.","Title: SPARK2: Top-k Keyword Query in Relational Databases\nYear: 2011\n\nAbstract: With the increasing amount of text data stored in relational databases, there is a demand for RDBMS to support keyword queries over text data. As a search result is often assembled from multiple relational tables, traditional IR-style ranking and query evaluation methods cannot be applied directly. In this paper, we study the effectiveness and the efficiency issues of answering top-k keyword query in relational database systems. We propose a new ranking formula by adapting existing IR techniques based on a natural notion of virtual document. We also propose several efficient query processing methods for the new ranking method. We have conducted extensive experiments on large-scale real databases using two popular RDBMSs. The experimental results demonstrate significant improvement to the alternative approaches in terms of retrieval effectiveness and efficiency.","Title: SPARK2: Top-k Keyword Query in Relational Databases\nYear: 2007\n\nAbstract: With the increasing amount of text data stored in relational databases, there is a demand for RDBMS to support keyword queries over text data. As a search result is often assembled from multiple relational tables, traditional IR-style ranking and query evaluation methods cannot be applied directly. In this paper, we study the effectiveness and the efficiency issues of answering top-k keyword query in relational database systems. We propose a new ranking formula by adapting existing IR techniques based on a natural notion of virtual document. We also propose several efficient query processing methods for the new ranking method. We have conducted extensive experiments on large-scale real databases using two popular RDBMSs. The experimental results demonstrate significant improvement to the alternative approaches in terms of retrieval effectiveness and efficiency.","Title: Robot control with a fully tuned Growing Radial Basis Function neural network\nYear: 2011\n\nAbstract: A fully tuned Growing Radial Basis Function (GRBF) neural network controller for the control of robot manipulators is proposed. In addition to the weights, the centers and the standard variations are adapted online. Furthermore, we present an algorithm in which nodes of the network are appended based on sliding window performance criteria. Lyapunov analysis is used to show uniform ultimate boundedness and a discretization method is used to derive the growing algorithm. Simulations of a 2-DOF planar robot arm are presented to illustrate the method.","Title: Improving Performance Using Interference Alignment on Modulation Signal for MIMO System\nYear: 2010\n\nAbstract: In this paper, an interference alignment system for the distributed MIMO network is investigated. We propose a new precoding scheme using interference alignment in modulation signal domain. The simulation results show that the proposed one-dimensional precoding scheme can provide significant performance improvement over the conventional schemes using interference alignment.","Title: Phrase-based statistical machine translation by using reordering search and additional features\nYear: 2006\n\nAbstract: The state of the art statistical machine translation (SMT) systems are based on phrase (a group of words), which are modeled using log-linear maximum entropy framework. In this paper, we constructed a phrase-based statistical machine translation system with additional feature models. The translation model is combined with four specific additional feature functions. When comparing our system with the baseline system of IWSLT2005, we can conclude that our system improve the SMT system accuracy with the same corpus.","Title: Object-Oriented Realization of Workflow Views for Web Services - An Object Deputy Model Based Approach\nYear: 2004\n\nAbstract: Adapted from the concept of views in databases, workflow views are derived form workflows as a fundamental support for workflow inter-operability and visibility by external parties in a web services environment. However, because of the implementation difficulties of views in OODB systems, it is tough to realize workflow views in objected-oriented workflow management systems (00 WFMS). In this paper, we adopt the object deputy model to support the realization of workflow views in 00 WFMS. The detailed definitions are given based on a reference model of an 00 WFMS, namely ADOME-WFMS. Furthermore, we introduce E-ADOME, which enables the implementation of workflow views in the web services environment.","Title: Iterative Minimum Mean Square Error Interference Alignment Scheme For The Mimo X Channel\nYear: 2011\n\nAbstract: In this paper, we propose a new interference alignment (IA) scheme that jointly designs the linear transmitter and receiver for the 2-user MIMO X channel system, using minimum total mean square error criterion, subject to each transmitter power constraint. We show that transmitters and receivers under such criteria could be realized through a joint iterative algorithm. Considering the imperfection of channel state information (CSI), we also extend the minimum mean square error interference alignment schemes for the MIMO X channel with CSI estimation error. A robust iterative algorithm which is insensitve to CSI estimation error is proposed. Simulation results are also provided to demonstrate the proposed algorithm.","Title: Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs\nYear: 2008\n\nAbstract: Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake - it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and time-consuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RRER Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SPR, and the simulation results confirm the effectiveness of the SRR approach.","Title: An optimistic checkpointing and message logging approach for consistent global checkpoint collection in distributed systems\nYear: 2008\n\nAbstract: Checkpointing and rollback recovery are widely used techniques for achieving fault-tolerance in distributed systems. In this paper, we present a novel checkpointing algorithm which has the following desirable features: A process can independently initiate consistent global checkpointing by saving its current state, called a tentative checkpoint. Other processes come to know about a consistent global checkpoint initiation through information piggy-backed with the application messages or limited control messages if necessary. When a process comes to know about a new consistent global checkpoint initiation, it takes a tentative checkpoint after processing the message (not before processing the message as in existing communication-induced checkpointing algorithms). After a process takes a tentative checkpoint, it starts logging the messages sent and received in memory. When a process comes to know that every other process has taken a tentative checkpoint corresponding to current consistent global checkpoint initiation, it flushes the tentative checkpoint and the message log to the stable storage. The tentative checkpoints together with the message logs stored in the stable storage form a consistent global checkpoint. Two or more processes can concurrently initiate consistent global checkpointing by taking a new tentative checkpoint; in that case, the tentative checkpoints taken by all these processes will be part of the same consistent global checkpoint. The sequence numbers assigned to checkpoints by a process increase monotonically. Checkpoints with the same sequence number form a consistent global checkpoint. We also present the performance evaluation of our algorithm.","Title: An Error Correction Method for Binary and Multiple-Valued Logic\nYear: 2011\n\nAbstract: This paper presents a method and circuit for correcting faults in logic systems. The method, called \"restorative feedback\" (RFB), is similar in some respects to triple modular redundancy (TMR), but has an improved error probability with respect to transient errors. Simulation results indicate an improvement by about two orders of magnitude compared to traditional TMR. CMOS circuits are presented for implementing restorative feedback. For binary logic, a dynamic CMOS circuit is considered. For multiple-valued logic, a semi-floating gate implementation is presented.","Title: Adaptive pressure ultrasonic precise bonding method for polymer micro joint\nYear: 2010\n\nAbstract: Ultrasonic precise bonding for polymer micro joint was studied. Considering shape deviation as the key issue to successful micro bonding, an ultrasonic bonding system was established, which employed 60 kHz ultrasonic transducer that achieved bonding at low amplitude. Adaptive ultrasonic bonding with bonding energy auto-selected was proposed. In this method, continues decreasing pressure was imposed on the micro components, the heat was accumulated and when the interface reached the melting point of the polymer, the pressure skip detected by the sensor and treated as the signal to turn off the ultrasonic vibration by the system. Polymer mechanical behavior was the control parameter in this method, precise energy for each component was auto-selected by system, and this solved the problem of surface roughness deviation form micro component and made small deformation of microstructure. Based on this method, linear guide was chosen to drive the ultrasonic horn. A kind of micro pump seat was bonded by this system. The joint had a transparent bonding interface and shear strength of 8 MPa which met the demand of MEMS. The interfacial temperature was measured during bonding. The influence of bonding pressure to the bonding quality was obtained. The result is contributed to ultrasonic bonding process optimizing and system design.","Title: Fast binary partition tree based variable-size block-matching for video coding\nYear: 2009\n\nAbstract: In this work, we develop a fast binary partition tree based variable size video coding system. New adaptive algorithms proposed herein are applied to a video encoder with binary partition trees. First, to reduce the computation for block-matching, an adaptive search area method is described which adjusts the searching region according to the size of each block. Second, an early termination method is introduced which terminates the binary partitioning process adaptively according to the statistics of the peak-signal-to-noise-ratio values during each step of block splitting. Third, we put forward a new model for fast rate-distortion (RD) estimation to decrease the computation of matching pursuit (MP) transform coding. Simulation results show that the proposed techniques provide significant gain in computation speed with little or no sacrifice of RD performance, when compared with non-adaptive binary partitioning scheme.","Title: How independent are the appearances of n-mers in different genomes?\nYear: 2004\n\nAbstract: Analysis of statistical properties of DNA sequences is important for evolutional biology as well as for DNA probe and PCR technologies. These technologies, in turn, can be used for organism identification, which implies applications in the diagnosis of infectious diseases, environmental studies, etc.We present results of the correlation analysis of distributions of the presence/absence of short nucleotide subsequences of different length ('n-mers', n = 5-20) in more than 1500 microbial and virus genomes, together with five genomes of multicellular organisms (including human). We calculate whether a given n-mer is present or absent (frequency of presence) in a given genome, which is not the usually calculated number of appearances of n-mers in one or more genomes (frequency of appearance). For organisms that are not close relatives of each other, the presence/absence of different 7-20mers in their genomes are not correlated. For close biological relatives, some correlation of the presence of n-mers in this range appears, but is not as strong as expected. Suppressed correlations among the n-mers present in different genomes leads to the possibility of using random sets of n-mers (with appropriately chosen n) to discriminate genomes of different organisms and possibly individual genomes of the same species including human with a low probability of error.","Title: A Stern-based Collusion-Secure Software Watermarking Algorithm and Its Implementation\nYear: 2007\n\nAbstract: Stern algorithm is a robust static software watermarking scheme. It can resist many common attacks except collusive attacks. In this paper we propose an improved Stern algorithm, make it has the ability of resisting collusive attacks and simplify its implementation at the same time. Furthermore, we describe the implementation of our algorithm and the issues that arise when targeting MSIL. We then validated it by experiments against a variety of attacks.","Title: On the performance of asynchronous ad-hoc networks using interference alignment with renewal process\nYear: 2013\n\nAbstract: The performance of ad-hoc networks is greatly affected by interference, particularly interference from nearby nodes. Based on stochastic geometry, this work studies a form of multiple-input-multiple-output (interference alignment (IA) that eliminates interference from transmitters within a range and treats the remaining interference as a shot noise process. Adapting to the bursty nature of ad-hoc network traffic, the authors introduce a novel distributed ad-hoc network with renewal process, whereby cooperation between interferer and receiver is implemented in one-way process, which results from the difficulties for the node to change the beamforming or receiving matrix whereas communicating with a proposed transmitter. In addition, this scheme takes advantage of IA, leaving the desired signal with higher degree of freedom (DoF) compared with the partially zero-forcing method. Outage probability and transmission capacity are derived with and without Rayleigh fading. Simulation results show the effect of IA in ad-hoc network, including the incremental in the DoF of the desired signal as time goes by. Monte Carlo simulations are implemented and show that IA outperforms successive interference cancellation by at least 10 dB in terms of the signal-to-interference ratio with large path-loss exponent.","Title: The New Interference Alignment Scheme for the MIMO Interference Channel\nYear: 2010\n\nAbstract: In this paper, we propose a new interference alignment (IA) scheme designing jointly the linear transmitter and receiver for the MIMO interference channel system, using minimum total mean square error criterion, subject to individual transmit power constraints. We show that transmitter and receiver under such criterion could be realized through a joint iterative algorithm. The convergence of the proposed algorithm is discussed. We also proposed a robust MMSE-based iterative design with imperfect channel state information (CSI). The proposed robust MMSE-based iterative interference alignment scheme is shown to be less sensitive to channel estimation errors. Simulation results show that the proposed schemes outperform the existing IA schemes with fast convergence.","Title: Learning Models of the Negotiation Partner in Spatio-temporal Collaboration\nYear: 2008\n\nAbstract: We describe an approach for learning the model of the opponent in spatio-temporal negotiation. We use the Children in the Rectangular Forest canonical problem as an example. The opponent model is represented by the physical characteristics of the agents: the current location and the destination. We assume that the agents do not disclose any of their information voluntarily; the learning needs to rely on the study of the offers exchanged during normal negotiation. Our approach is Bayesian learning, with the main contribution being four techniques through which the posterior probabilities are determined. The calculations rely on (a) feasibility of offers, (b) rationality of offers, (c) the assumption of decreasing utility, and (d) the assumption of accepting offer which is better than the next counter-offer.","Title: Performance of homogeneous and asynchronous ad hoc network with interference alignment\nYear: 2013\n\nAbstract: In this work, we introduce multiple-input-multiple-output (MIMO) interference alignment (IA) in an homogeneous and asynchronous ad hoc network. Perfect channel state information and working status of nodes are conveyed by instantaneous feedback link to one-hop neighbors. Transmitters align their interference to receivers and receivers eliminate interference by zero-forcing method asynchronously. The feasibility conditions for IA are considered as a critical factor to the performance, and the situations are divided according to whether the feasibility condition can be satisfied or not. We derive closed-form expressions for the upper and lower bounds on outage probability and transmission capacity in both cases. Numerical results show that with larger path loss exponent and number of antennas, the performance increases because a greater proportion of the interference can be eliminated.","Title: A game theory based risk and impact analysis method for Intrusion Defense Systems\nYear: 2009\n\nAbstract: An enormous amount of functions in our everyday life became dependent on computer networks. Network attacks become more sophisticated and perplexing. Defending against multi-stage attacks is a challenging process in intrusion defense systems (IDS) due to their complexity. This paper presents a game theory method to analyze the risk and impact of multi-stage attacks in IDS. In this method, the interactions between the attacker and the administrator are modeled as a non-cooperative zero-sum multistage game and it is modeled as a minmax game tree where the attacker is the leader and the administrator is the follower. Alternating the actions between the administrator and the attacker forms the game tree, each of them will be allowed to play a single action at any given time. In this work, a new multi-stage attacker defender (MAD) algorithm is developed to help the administrator in defending against multi-stage attacks. The believes of the attacker and the administrator are updated based on the analysis of the life-cycle for the multi-stage attacks to reduce the horizon effect.","Title: Similarity search with implicit object features\nYear: 2005\n\nAbstract: Driven by many real applications, in this paper we study the problem of similarity search with implicit object features; that is, the features of each object are not pre-computed/evaluated. As the existing similarity search techniques are not applicable, a novel and efficient algorithm is developed in this paper to approach the problem. The R-tree based algorithm consists of two steps: feature evaluation and similarity search. Our performance evaluation demonstrates that the algorithm is very efficient for large spatial datasets.","Title: Study of polymeric MEMS micro-pump actuated by PZT bimorph\nYear: 2013\n\nAbstract: Check valve micro-pump is easy to reach high flow rate and has a promising application prospect in micro fluidic devices and artificial organs. There are several vibration elements in check valve pump, including actuator, membrane and valves. The vibration performances of these elements have a coupling influence on the performance of micro-pump. In this paper, the comprehensive analysis was carried out using finite element model. Four kinds of micro-pumps with different valves and actuators were designed and fabricated. The performances of each kind of micro-pumps are studied by frequency sweeping experiments. Experimental results approximately coincide with the theoretical analysis. This research provides a theoretical and experimental basis for subsequent micro-pump design.","Title: A radiosonde using a humidity sensor array with a platinum resistance heater and multi-sensor data fusion.\nYear: 2013\n\nAbstract: This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes.","Title: Novel back-to-back uni-traveling-carrier photodiodes with high responsivity and wide bandwidth\nYear: 2013\n\nAbstract: Novel back-to-back uni-traveling-carrier photodiodes are proposed and demonstrated. High responsivity of 0.83 A/W and wide bandwidth over 40 GHz are realized simultaneously in mesa-structure photodiodes for the first time. © 2013 OSA.","Title: Cooperative Wideband Spectrum Detection Based on Maximum Likelihood Ratio for CR Enhanced VANET.\nYear: 2013\n\nAbstract: Cognitive radio (CR) enhanced vehicular ad hoc network (CR-VANET) is a special VANET that each vehicle could explore local spectrum gap and reduce data congestion by mitigating interference by dynamically accessing spectrum holes. One of the most important challenges for CR-VANET is to identify the presence of primary users (PU) over wideband spectrum at a particular time and specific geographic location. In this paper, maximum likelihood ratio (MLR) detection is proposed as an effective scheme for wideband spectrum detection in orthogonal frequency division multiplexing (OFDM) based overlay CR-VANET. OR fusion rule with square-law selection (SLS) is implemented at roadside to make global detection decision by means of the combination of each vehicle's local sensing results. Hence, cooperative wideband spectrum detection is implemented in dynamic topology CR-VANET to enhance the reliability of spectrum detection. Specifically, robust cooperative sensing technique is investigated with the consideration of sensing channel SNR, reporting channel fading, as well as inter-user error rate, with the purpose of exploiting diversity in multi-vehicle cooperative sensing scenario. Limitations of cooperative wideband spectrum sensing are presented with MLR detection in space-time block code (STBC) and time division multiple access (TDMA) protocols for practical consideration. Simulation results are presented to confirm our theoretical derivations. It is revealed that, compared with conventional energy detection (ED), cooperative wideband spectrum detection with MLR has adaptive detection thresholds. Moreover, robust cooperative sensing by roadside SLS OR rule and its limitations are also performed with receiver operation characteristics (ROC). It is proven that, MLR detection is available in robust cooperative sensing with dynamic threshold variations for CR-VANET practical applications. © 2013 Engineering and Technology Publishing.","Title: Evaluation of non-water-stressed baselines for crop water stress monitoring in North China Plain\nYear: 2002\n\nAbstract: Canopy surface temperature measured with infrared thermometers or other remote IR sensor is an important tool for crop water stress monitoring. Crop Water Stress Index (CWSI) is the most often used index to detect crop water stress based on canopy surface temperature. The calculation of CWSI relies on two baselines: the non-water-stressed baseline, and the maximum stressed baseline. This paper evaluates the application of the most often used non-water-stressed baselines in North China Plain (NCP): the Idso's empirical baseline, and the Jackson's theoretical baseline. The results show that the Jackson's model makes better than the Idso's in monitoring winter wheat water stress in NCP.","Title: Error Correction via Restorative Feedback in M-ary Logic Circuits.\nYear: 2014\n\nAbstract: This paper presents an error correction method known as restorative feedback (RFB) that provides error-correction for both permanent and temporal logic faults in any M-ary logic system. The RFB method is a variant of triple modular redundancy (TMR), which achieves error correction in logic circuits by using three-fold redundancy. Unlike TMR, the RFB method has well-defined application to arbitrary M-ary logic systems as well as conventional binary logic circuits. The RFB method also uses a feedback mechanism to suppress transient errors, resulting in a lower error probability than TMR when considering transient upsets. The underlying theory of RFB is presented as an adaptation of stochastic error correction theory. Two circuit-level proof-of-concept demonstrations are presented, which include a binary implementation using Muller C-elements, and a ternary implementation based on Semi-Floating Gate logic circuits. The error-correcting performance of these circuits is evaluated using logic-level simulations as well as devicelevel simulations in Spectre. Bit and symbol error rates are also computed using Monte Carlo simulations which demonstrate that the RFB method is superior to traditional TMR for a variety of cases. An application of the RFB method is also demonstrated using redundant gate-level synthesis of multiple-valued ripple-carry adder circuits. The application circuits are simulated using an abstract noisy-logic model, and the RFB method is shown to significantly improve the circuits' noise immunity.","Title: Degrees-of-Freedom Regions for $K$-User MISO Time-Correlated Broadcast Channel.\nYear: 2014\n\nAbstract: In this paper, we study the achievable degrees-of-freedom (DoF) regions of the $K$-user multiple-input-single-output (MISO) time correlated broadcast channel (BC). The time correlation induces knowledge of the current channel state information at transmitter (CSIT) with an estimation error $P^{-\\alpha}$, where $P$ is the signal-to-noise ratio (SNR). We consider the following two scenarios: $(i)$ $K$-user with $K$-antenna base station (BS) and $(ii)$ $3$-user with $2$-antenna BS. In case of symmetric DoF tuples, where all the users obtain the same DoF, we derive the total DoF equal to $\\frac{K(1-\\alpha)}{1+\\frac{1}{2}+\\cdots+\\frac{1}{K}}+K\\alpha$ for the first scenario and $\\frac{3+\\alpha}{2}$ for the second one. In particular, we provide the achievability schemes for these two DoF tuples. Nevertheless, we also consider the asymmetric case where one of the users is guaranteed {\\it one} DoF, and provide the achievability scheme. Notably, the consistency of the proposed DoF regions with an already published outer bound , as well as with the Maddah-Ali-Tse (MAT), which assumes only perfect delayed CSIT, and the ZF beamforming schemes (perfect current CSIT) consents to the optimality of the proposed achievability schemes.","Title: Linked vaccine adverse event data from VAERS for biomedical data analysis and longitudinal studies.\nYear: 2014\n\nAbstract: Vaccines have been one of the most successful public health interventions to date. The use of vaccination, however, sometimes comes with possible adverse events. The U.S. FDA/CDC Vaccine Adverse Event Reporting System (VAERS) currently contains more than 200,000 reports for post-vaccination events that occur after the administration of vaccines licensed in the United States. Although the data from the VAERS has been applied to many public health and vaccine safety studies, each individual report does not necessarily indicate a casuality relationship between the vaccine and the reported symptoms. Further statistical analysis and summarization needs to be done before this data can be leveraged.This paper introduces our efforts on representing the vaccine-symptom correlations and their corresponding meta-information extracted from the VAERS database using Resource Description Framework (RDF). Numbers of occurrences of vaccine-symptom pairs reported to the VAERS were summarized with corresponding proportional reporting ratios (PRR) calculated. All the data was stored in an RDF file. We then applied network analysis approaches to the RDF data to illustrate a use case of the data for longititual studies. We further dicussed our vision on integrating the data with vaccine information from other sources using RDF linked approach to facilitate more comprehensive analyses.The 1990-2013 data from VAERS has been extracted from the VAERS database. There are 83,148 unique vaccine-symptom pairs with 75 vaccine types and 5,865 different reported symptoms. The yearly and over PRR values for each reported vaccine-symptom pair were calculated. The network properties of networks consisting of significant vaccine-symptom associations (i.e., PRR larger than 1) were then investigated. The results indicated that vaccine-symptom association network is a dense network, with any given node connected to all other nodes through an average of approximately two other nodes and a maximum of five nodes.","Title: Degrees of freedom region of MIMO interference channel with imperfect current and delayed CSIT\nYear: 2014\n\nAbstract: In this paper, we study the degrees of freedom (DoF) of the two-user time-correlated multiple-input-multiple-output (MIMO) interference channel (IC), under realistic assumptions. In particular, the transmitters have imperfect knowledge of the current and the delayed channel state information (CSI). The novelty of this study relies upon the fact that this is the first time, within the literature of IC, that imperfect CSI is addressed for such a case. The delayed CSI at the transmitter (CSIT) is assumed to be more accurate than the current value. We identify the DoF region, which provides an insight on the behaviour of the DoF as a function of the varying qualities of the current and the delayed channel. It is also worth mentioning that any knowledge of imperfect delayed CSIT can also be utilized. Furthermore, an achievability scheme is proposed for each vertex in DoF region. Finally, simulation of the proposed scheme verifies our results.","Title: Managing Large Scale Unstructured Data with RDBMS\nYear: 2013\n\nAbstract: With the rapid development of information technology, the needs of unstructured data storage and processing is growing rapidly, which develops a new requirement for the database storage. Traditional row-oriented relational databases appear to be inadequate for the data query and analysis. In this paper, we propose a novel approach to store the unstructured data in a relational database. By splitting the VALUE property of the unstructured KEY/VALUE data and recreating the two-dimensional data, the original data can be stored in relational databases. The system introduced in this paper is designed to handle this task. In addition, this system rebuilds the SQL as its query language, which makes it compatible with relational databases. In experiments of the query for unstructured data, the outcomes show that the system is good at decomposing the SQL statement submitted by users, and generating the corrected sub-query statements. The results of the experiments show that the performance of this system is good.","Title: An Empirical Algorithm for Bias Correction Based on GC Estimation for Single Cell Sequencing.\nYear: 2014\n\nAbstract: Whole genome amplification (WGA) have been applied to single cell copy number variations (CNVs) analysis, which is a common genomic mutation associated with various diseases and provides new insight for the fields of biology and medicine. However, the WGA-induced bias based on multiple displacement amplification (MDA) significantly limits sensitivity and specificity for CNVs detection. To address the limitations, an empirical algorithm for CNVs detection at single cell level was developed. This proposed method consists of base call amplification, alig- nment and analysis to remove the MDA-induced bias. We generated and analyzed about 50G short read data sets based on MDAsim, a software to amplify the chromosome 21 into various coverage. Simulation experiments have shown that the coverage tended to be less than average in genomic GC-enriched (>45 %) regions, implying a significant amplification bias within these regions. Base substitution error frequencies with G > A transversion is being among the most frequent and C > T, G > T transversions are among the least frequent substitution errors. The estimated substitution was employed to compensate errors to correct bias readings.","Title: SemIndex: Semantic-Aware Inverted Index.\nYear: 2014\n\nAbstract: This paper focuses on the important problem of semantic-aware search in textual (structured, semi-structured, NoSQL) databases. This problem has emerged as a required extension of the standard containment keyword based query to meet user needs in textual databases and IR applications. We provide here a new approach, called SemIndex, that extends the standard inverted index by constructing a tight coupling inverted index graph that combines two main resources: a general purpose semantic network, and a standard inverted index on a collection of textual data. We also provide an extended query model and related processing algorithms with the help of SemIndex. To investigate its effectiveness, we set up experiments to test the performance of SemIndex. Preliminary results have demonstrated the effectiveness, scalability and optimality of our approach.","Title: Robust beamforming for two-user MISO broadcasting channel with delayed CSIT\nYear: 2014\n\nAbstract: Recently proposed MAT1 scheme achieves high degrees of freedom (DoF) by exploiting delayed channel state information at transmitter side (CSIT) and the concept of interference alignment (IA), where the interference vectors of different time slots are aligned. As the starting work, MAT scheme considers no flexibility when reconstructing symbols at the third time slot, which may lead to performance degradation once the channel varies. In this paper, a probabilistic optimization problem is proposed with the assumption that the unknown channel entries follow given distribution. Instead of maximizing the sum rate directly, we strive to maximize the signal power while keeping the high probability that the interference power is lower than a pre-specified threshold. The Monte Carlo simulation results show that the proposed scheme outperforms the MAT scheme and dual SINR scheme with various channel uncertainties.","Title: A biped humanoid robot's gait planning method based on Artificial Immune Network\nYear: 2014\n\nAbstract: A biped humanoid robot model with 12 degree of freedom is developed in this paper. To facilitate the gait pattern planning, the 3D inverted pendulum model and the ZMP are introduced to enable a human-like stable walking. Since the searching of best walk primitive is a multi-objective optimization problem, a modified aiNet Algorithm as well as SGA Algorithm is applied to the optimization process. Finally, the control parameters worked out by both algorithms are verified and compared in simulation. We find out that the result of aiNet provides the robot with better stability than SGA while they are similar in mobility.","Title: On optimal strategies in protecting computer networks\nYear: 2011\n\nAbstract: Strategies of defending a computer network against random attacks are modeled by probabilistic methods. A single-stage model is introduced to find the optimal allocation of the resources of the administrator when the network has multiple possible targets. The location of the actual attack is random, the probability of which can be assessed by the administrator from previous interactions with the attacker and based on intelligence information. The expected value and the variance are combined to find the certain equivalent of the outcome, which depends on the allocation of the resources of the administrator between the vulnerabilities of the network. The mathematical model is a nonconvex programming problem, so application of standard optimization techniques cannot guarantee global optimum. By introducing new decision variables the problem can be transformed into a convex problem, the optimal solutions of which can be determined by a simple algorithm by solving a single-variable monotonic equation. This procedure makes the administrator able to find optimal resource allocations very fast and therefore can respond almost instantaneously.","Title: 125Mbps ultra-wideband system evaluation for cortical implant devices.\nYear: 2012\n\nAbstract: This paper evaluates the performance of a 125Mbps Impulse Ratio Ultra-Wideband (IR-UWB) system for cortical implant devices by using low-Q inductive coil link operating in the near-field domain. We examine design tradeoffs between transmitted signal amplitude, reliability, noise and clock jitter. The IR-UWB system is modeled using measured parameters from a reported UWB transceiver implemented in 90nm-CMOS technology. Non-optimized inductive coupling coils with low-Q value for near-field data transmission are modeled in order to build a full channel from the transmitter (Tx) to the receiver (Rx). On-off keying (OOK) modulation is used together with a low-complexity convolutional error correcting code. The simulation results show that even though the low-Q coils decrease the amplitude of the received pulses, the UWB system can still achieve acceptable performance when error correction is used. These results predict that UWB is a good candidate for delivering high data rates in cortical implant devices.","Title: Automated exploration of stable isomers of H(+)(H(2)O)(n) (n = 5-7) via ab initio calculations: An application of the anharmonic downward distortion following algorithm.\nYear: 2009\n\nAbstract: Isomers of protonated water clusters H+(H2O)(n) (n = 5-7) have been explored on ab initio potential energy surfaces by means of the anharmonic downward distortion following algorithm. Totally, 9, 24, and 131 isomers for n = 5, 6, and 7, respectively, were located by the automatic exploration, and all of known important isomers previously reported by conventional geometry optimization approaches have been included in the present results. Moreover, structure transitions depending on n and temperature, which were observed by experimental studies, could be reproduced via thermodynamic simulation on the basis of the superposition approach and the present isomer sets. (C) 2008 Wiley Periodicals, Inc. J Comput Chem 30: 952-961, 2009","Title: A human ECG identification system based on ensemble empirical mode decomposition.\nYear: 2013\n\nAbstract: In this paper, a human electrocardiogram (ECG) identification system based on ensemble empirical mode decomposition (EEMD) is designed. A robust preprocessing method comprising noise elimination, heartbeat normalization and quality measurement is proposed to eliminate the effects of noise and heart rate variability. The system is independent of the heart rate. The ECG signal is decomposed into a number of intrinsic mode functions (IMFs) and Welch spectral analysis is used to extract the significant heartbeat signal features. Principal component analysis is used reduce the dimensionality of the feature space, and the K-nearest neighbors (K-NN) method is applied as the classifier tool. The proposed human ECG identification system was tested on standard MIT-BIH ECG databases: the ST change database, the long-term ST database, and the PTB database. The system achieved an identification accuracy of 95% for 90 subjects, demonstrating the effectiveness of the proposed method in terms of accuracy and robustness.","Title: Modeling the Strategic Behavior of Drivers for Multi-Lane Highway Driving\nYear: 2015\n\nAbstract: Current state-of-the-art highway traffic flow simulators rely extensively on models using formulas similar to those describing physical phenomena, such as forces, viscosity, or potential fields. These models have been carefully calibrated to represent the overall flow of traffic and they can also be extended to account for the cognitive limitations of the driver, such as reaction times. However, there are some aspects of driver behavior, such as strategic planning, that are difficult to formulate mathematically. In this article, we describe the YAES-DSIM highway simulator, which integrates virtual physics models with an agent-based model. The virtual physics component models the physical vehicle and the subconscious aspects of the driver behavior, while the agent component is responsible for the strategic and tactical decisions, which are difficult to model using virtual physics. We focus on the lane change decisions of the drivers, with special attention to the optimal lane positioning for a safe exit. We have used the model to simulate the flow of traffic on Highway 408 in Orlando, Florida, and to study the impact of various tactical and strategic decisions on the efficiency and safety of the traffic.","Title: Analysis of the information theoretically secret key agreement by public discussion\nYear: 2015\n\nAbstract: Generally, the information theoretically secret key agreement by public discussion consists of three phases, namely, advantage distillation, information reconciliation, and privacy amplification. In the existing literatures, these three phases are studied separately, and no comprehensive consideration has been given. In this paper, we analyze the restrictive relationship among these three phases from an overall point of view. For the satellite scenario, we analyze in detail the Winnow protocol for the first time. We also present the mutual restrictive relationship between the parameters of the advantage distillation phase and the information reconciliation phase. We further address how to set the parameters of the advantage distillation and the information reconciliation to maximize the total secret key agreement efficiency. Moreover, we determine the required length range of the initial random key string to guarantee the validation of the secret key agreement. Copyright © 2015 John Wiley & Sons, Ltd.","Title: Identification of sex-associated network patterns in Vaccine-Adverse Event Association Network in VAERS\nYear: 2015\n\nAbstract: We have developed a network-based approach to investigate the vaccine-AE association network from the VAERS data. To our knowledge, this is the first time that a network-based approach was used to identify sex-specific association patterns in a spontaneous reporting system database. Due to unique limitations of such passive surveillance systems, our proposed network-based approaches have the potential to summarize and analyze the associations in passive surveillance systems by (1) identifying nodes of importance, irrespective of whether they are disproportionally reported; (2) providing guidance on sex-specific recommendations in personalized vaccinology.","Title: Remote Sensing Of Regional Crop Transpiration Of Winter Wheat Based On Modis Data And Fao-56 Crop Coefficient Method\nYear: 2013\n\nAbstract: Crop evapotranspiration is one of the most important parameters of farmland water cycle, which consists of crop transpiration (T-c) and soil evaporation. As the efficient component for crop production, T-c and its accurate determination, especially on a regional scale, is very critical for scientific design of irrigation scheduling and high-efficiency utilization of water resources. In this work, the T-c of winter wheat over an irrigation area located in the lower Yellow River of China was estimated by combining MODIS data and FAO-56 crop coefficient method. Specifically, the relationships between the single crop coefficient (K-c), basal crop coefficient (K-cb) and canopy vegetation indices were investigated and compared based on field data. Then, the actual K-cb map of winter wheat over the study area was estimated with MODIS-derived soil adjusted vegetation index (SAW) using the relationship obtained from above field investigations. Finally, the T-c of winter wheat over the area was determined as the product of K-cb and reference crop evapotranspiration (ET0). ET0 was calculated from meteorological data, and then were spatially interpolated to obtain the regional map matching with the remotely sensed K-cb. It was found that compared with K-c, K-cb was much more closely related to the vegetation indices of NDVI, SAVI, and EVI, even in the presence of nitrogen and water stress, with the coefficients of determination (R-2) being 0.60, 0.67 and 0.68 respectively (n = 195) which could be even higher without the water-stress points that had not reached the severity to make obvious changes in canopies. Results also demonstrated that it was feasible to utilize the K-cb-SAVI relationship to derive the K-cb of winter wheat over a large area by means of satellite remote sensing, and that it was effective to determine regional crop T-c using the above approach. It would be useful in practical application due to the advantages of easy operation and separating soil evaporation effectively.","Title: Leading in the digital age: A study of how social media are transforming the work of communication professionals\nYear: 2016\n\nAbstract: •Communication professionals used social media extensively in their work.•Social media use was closely related to professionals’ leadership behaviors.•Demographics and psychographics impacted professionals’ social media management.•Communication professionals’ strategic vision predicted their social media use.","Title: Using peristaltic pump to charge micro heat pipe for high-power LED\nYear: 2015\n\nAbstract: A novel perfusion method of micro heat pipe(MHP) is presented in this paper. The MHP has length of 26mm, width of 20 mm, and thickness of approximate 2.2mm. The predetermined quantity of perfusion is 25µl. Small volume and large capillary force render conventional vacuum perfusion methods quite impractical. In order to realize microscale and high precision of perfusion, the method of combining the vacuum perfusion using peristaltic pump and weight comparison before and after working fluid charging together was used. The charging deviation of the method was less than 2µl. And after perfusion and sealing, the thermal performance testing of MHP, which is engineered in LED heap dissipation, was conducted and the input power varied from 1W to 7W. The results show that high power LED can reach the status of heat balance and can work steadily. Therefore, this perfusion method can be used to working fluid perfusion of MHP and makes it feasible that it is used for packaging manufacture of heat pipe.","Title: Throughput Of Two-Tier Heterogeneous Wireless Networks With Interference Coordination\nYear: 2014\n\nAbstract: Two-tier heterogeneous wireless networks are considered in this paper where nodes in the first tier are distributed as a Poisson Point Process (PPP). Nodes in the second tier are distributed as a Poisson Clustered Process (PCP). Nodes in the second tier have imperfect channel state information (CSI) of the first tier node whose Voronoi cell they are in. On one hand, cross-tier interference is coordinated to the second tier nodes by interference alignment (IA) approach, where we strike a balance between increasing the number of data streams and increasing signal-to-interference (SIR) ratio at each data stream. On the other hand, the remaining interference is modelled by stochastic geometry and analytic expressions of throughput are derived. Monte Carlo simulations validate our expressions and show the gain brought by the interference coordination approach.","Title: Measurement of subsidence in the Yangbajing geothermal fields, Tibet, from TerraSAR-X InSAR time series analysis.\nYear: 2016\n\nAbstract: Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. In the case of the TerraSAR-X data, most orbital fringes were removed using precise orbits during the interferometric processing. However, residual orbital ramps remain in some interferograms due to the uncertainties in the TerraSAR-X orbits. To remove the residual orbital ramps, we estimated a best-fit `twisted plane' for each epoch interferogram using quadratic polynomial models based on a network approach. This method removes most of the long-wavelength signals, including orbit ramps and atmospheric effects. The vertically stratified component (Topography Correlated Atmospheric Delay, TCAD) was also removed using a network approach. If the influence of seasonal frozen ground (SFG) is not taken into consideration, our results show that the subsidence rate around power plant I (the south plant) is approximately 20 mm/yr with a peak of 30 mm/yr. The subsidence rate around power plant II (the north plant) is approximately 10 mm/yr, when accounting for the influence of SFG on the power plant and its surrounding ground surface. Our results show that ground motion is caused by seasonal frozen ground and is strongly related to the temperature change.","Title: Deep clustering and conventional networks for music separation: Stronger together\nYear: 2017\n\nAbstract: Deep clustering is the first method to handle general audio separation scenarios with multiple sources of the same type and an arbitrary number of sources, performing impressively in speaker-independent speech separation tasks. However, little is known about its effectiveness in other challenging situations such as music source separation. Contrary to conventional networks that directly estimate the source signals, deep clustering generates an embedding for each time-frequency bin, and separates sources by clustering the bins in the embedding space. We show that deep clustering outperforms conventional networks on a singing voice separation task, in both matched and mismatched conditions, even though conventional networks have the advantage of end-to-end training for best signal approximation, presumably because its more flexible objective engenders better regularization. Since the strengths of deep clustering and conventional network architectures appear complementary, we explore combining them in a single hybrid network trained via an approach akin to multi-task learning. Remarkably, the combination significantly outperforms either of its components.","Title: Deep attractor network for single-microphone speaker separation\nYear: 2017\n\nAbstract: Despite the overwhelming success of deep learning in various speech processing tasks, the problem of separating simultaneous speakers in a mixture remains challenging. Two major difficulties in such systems are the arbitrary source permutation and unknown number of sources in the mixture. We propose a novel deep learning framework for single channel speech separation by creating attractor points in high dimensional embedding space of the acoustic signals which pull together the time-frequency bins corresponding to each source. Attractor points in this study are created by finding the centroids of the sources in the embedding space, which are subsequently used to determine the similarity of each bin in the mixture to each source. The network is then trained to minimize the reconstruction error of each source by optimizing the embeddings. The proposed model is different from prior works in that it implements an end-to-end training, and it does not depend on the number of sources in the mixture. Two strategies are explored in the test time, K-means and fixed attractor points, where the latter requires no post-processing and can be implemented in real-time. We evaluated our system on Wall Street Journal dataset and show 5.49% improvement over the previous state-of-the-art methods.","Title: Linking Heterogeneous Data in the Semantic Web Using Scalable and Domain-Independent Candidate Selection.\nYear: 2017\n\nAbstract: Due to the decentralized nature of the Semantic Web, the same real-world entity may be described in various data sources with different ontologies and assigned syntactically distinct identifiers. In order to facilitate data utilization and consumption in the Semantic Web, without compromising the freedom of people to publish their data, one critical problem is to appropriately interlink such heterogeneous data. This interlinking process is sometimes referred to as Entity Matching, i.e., finding which identifiers refer to the same real-world entity. In this paper, we propose two candidate selection algorithms to improve the scalability of entity matching systems. First of all, we propose HistSim that utilizes the matching histories of the instances to prune instance pairs that are not sufficiently similar to the same pool of other instances. A sigmoid function based thresholding method is proposed to automatically adjust the threshold for such commonality on-the-fly. Furthermore, we propose DisNGram that selects candidate instance pairs by computing a character-level similarity metric on discriminating literal values that are chosen using domain-independent unsupervised learning. Instances are indexed on the chosen predicates’ literal values to enable efficient look-up for similar instances. Finally, in order to be able to handle heterogeneous datasets with a large number of predicates, a mechanism for automatically determining predicate comparability is proposed. We evaluate our two candidate selection algorithms against six state-of-the-art systems on three Semantic Web datasets, and demonstrate that our proposed algorithms frequently outperform state-of-the-art systems on F1-score and runtime.","Title: A CMOS pixel design with binary space-time exposure encoding for computational imaging\nYear: 2017\n\nAbstract: A CMOS pixel design that is capable of spatialtemporal exposure encoding is presented. By integrating selective charge storage units and exposure code memories in an active pixel sensor (APS) structure, the 10 μm×10 μm pixel design performs intermittent exposure according to the received binary exposure codes. Under a 625 nm illumination and with a 3.3 V supply, a 10×10 prototype image sensor fabricated in a 0.13-μm CMOS process demonstrates temporal, spatial, and spatialtemporal exposure encoding at 60 fps. The proposed pixel structure facilitates focal-plane space-time exposure encoding in CMOS image sensors for computational imaging applications.","Title: Optimal Lateral Trajectory Tracking using Backstepping with a Fully Tuned Growing RBF Neural Network.\nYear: 2012\n\nAbstract: This paper will present an approach to aircraft lateral trajectory tracking utilizing backstepping control with a fully-tuned Growing Radial Basis Function (GRBF) neural network. The aircraft lateral trajectory is generated via optimization of a cost functional using the Pontryagin maximum principle. The fully tuned growing RBF network is utilized to compensate for unknown perturbations in the aircraft model. Simulations are presented for an optimal turn and descent trajectory.","Title: Always-on CMOS image sensor pixel design for pixel-wise binary coded exposure.\nYear: 2017\n\nAbstract: Pixel-wise coded exposure, as an emerging field of research in computational imaging, is widely implemented in applications such as high-speed imaging, compressive sensing, and focal-stack imaging. In this paper, a complementary metal-oxide-semiconductor (CMOS) pixel design for binary coded exposure is presented. Based on an always-on charge distribution structure, the proposed pixel achieves programmable charge selection. A prototype image sensor chip, fabricated in a 0.13-μm CMOS process demonstrates pixelu0027s capability of binary exposure encoding in 60 fps while operating from a 3.3 V supply.","Title: Feasibility analysis of data transmission in SDN.\nYear: 2017\n\nAbstract: In the setting of software definition network (SDN), whether there exists an available transmission plan between any two sites is equal to whether there exists a fractional factor after deleting certain vertices and edges in the corresponding graph. A graphGis called a fractional ID-(a, b, m)-deleted graph if after deleting any independent-set I, the remaining graph G - I is a fractional (a, b, m)-deleted graph. A fractional (g, f)-factor F of a graph G is called a Hamiltonian fractional (g, f)-factor if F includes a Hamiltonian cycle. Furthermore, we say that G has a ID-Hamiltonian fractional (g, f)-factor if after deleting any independent set of G the remaining graph of G includes a Hamiltonian fractional (g, f)-factor. In this paper, we first give a binding number condition for a graph to be a fractional ID-(a, b, m)-deleted graph, and then two sufficient conditions for graphs to have ID-Hamiltonian fractional (g, f)-factors are obtained.","Title: A Small UAV Based Multi-Temporal Image Registration for Dynamic Agricultural Terrace Monitoring.\nYear: 2017\n\nAbstract: Terraces are the major land-use type of agriculture and support the main agricultural production in southeast and southwest China. However, due to smallholder farming, complex terrains, natural disasters and illegal land occupations, a light-weight and low cost dynamic monitoring of agricultural terraces has become a serious concern for smallholder production systems in the above area. In this work, we propose a small unmanned aerial vehicle (UAV) based multi-temporal image registration method that plays an important role in transforming multi-temporal images into one coordinate system and determines the effectiveness of the subsequent change detection for dynamic agricultural terrace monitoring. The proposed method consists of four steps: (i) guided image filtering based agricultural terrace image preprocessing, (ii) texture and geometric structure features extraction and combination, (iii) multi-feature guided point set registration, and (iv) feature points based image registration. We evaluated the performance of the proposed method by 20 pairs of aerial images captured from Longji and Yunhe terraces, China using a small UAV (the DJI Phantom 4 Pro), and also compared against four state-of-the-art methods where our method shows the best alignments in most cases.","Title: Nonrigid Image Registration for Low-Altitude SUAV Images With Large Viewpoint Changes.\nYear: 2018\n\nAbstract: Low-altitude aerial photography using small unmanned aerial vehicles (SUAVs) with large viewpoint changes causes nonrigid distortions and low overlap ratios. We present a nonrigid feature-based low-altitude SUAV image-registration method. The key idea of our method is to maintain a high matching ratio on inliers while taking advantage of outliers for varying the warping grids. Thus, accurate image...","Title: Speaker-Independent Speech Separation With Deep Attractor Network.\nYear: 2018\n\nAbstract: Despite the recent success of deep learning for many speech processing tasks, single-microphone, speaker-independent speech separation remains challenging for two main reasons. The first reason is the arbitrary order of the target and masker speakers in the mixture (permutation problem), and the second is the unknown number of speakers in the mixture (output dimension problem). We propose a novel ...","Title: Secure and Efficient Access Control Scheme for Wireless Sensor Networks in the Cross-Domain Context of the IoT.\nYear: 2018\n\nAbstract: Nowadays wireless sensor network (WSN) is increasingly being used in the Internet of Things (IoT) for data collection, and design of an access control scheme that allows an Internet user as part of IoT to access the WSN becomes a hot topic. A lot of access control schemes have been proposed for the WSNs in the context of the IoT. Nevertheless, almost all of these schemes assume that communication nodes in different network domains share common system parameters, which is not suitable for cross-domain IoT environment in practical situations. To solve this shortcoming, we propose a more secure and efficient access control scheme for wireless sensor networks in the cross-domain context of the Internet of Things, which allows an Internet user in a certificateless cryptography (CLC) environment to communicate with a sensor node in an identity-based cryptography (IBC) environment with different system parameters. Moreover, our proposed scheme achieves known session-specific temporary information security (KSSTIS) that most of access control schemes cannot satisfy. Performance analysis is given to show that our scheme is well suited for wireless sensor networks in the cross-domain context of the IoT.","Title: Multi-Parameter-Setting Based On Data Original Distribution For Denclue Optimization\nYear: 2018\n\nAbstract: DENCLUE is a typical density-based clustering method, and it also is an important pattern classification analysis technique. In this clustering method, the propriety of parameters' values greatly infiuences the quality of distinguishing. Accordingly, how to choose an appropriate value of every parameter is a problem that is worth studying. The problem is focused in this paper, and a method which is very different from previous ones is presented. The highlight of the method is that the selection of parameters no longer depends on personal experience but on data original distribution. More specifically, smoothing parameter h is more or less proportional to the average value of distance between two arbitrary data points; step size delta is adapted according to the density of data points in the hill-climbing progress; noise threshold xi is replaced by delta and total number of data points. Compared with the original DENCLUE and an improved DENCLUE proposed in our previous research, the optimized algorithm can bring better clustering from experiments. In addition, due to the adaptiveness of delta, the method will become less complex.","Title: Exposure-Programmable CMOS Pixel With Selective Charge Storage and Code Memory for Computational Imaging.\nYear: 2018\n\nAbstract: Computational imaging, as a rapid emerging field, enables unprecedented photographic capability through the encoding of visual information. Currently, as exposure programming is not support by image sensors, computational cameras use off-chip components to accomplish exposure/encoding optical computations. In this paper, we present a complementary metal-oxide-semiconductor (CMOS) pixel structure w...","Title: Chaotic behavior of discrete-time linear inclusion dynamical systems.\nYear: 2017\n\nAbstract: Given any finite family of real d-by-d nonsingular matrices {S1,…,Sl}, by extending the well-known Li–Yorke chaos of a deterministic nonlinear dynamical system to a discrete-time linear inclusion or hybrid or switched system:\nxn∈{Skxn−1;1≤k≤l},x0∈Rdandn≥1,we study the chaotic dynamics of the state trajectory (xn(x0, σ))n ≥ 1 with initial state x0∈Rd, governed by a switching law σ:N→{1,…,l}. Two sufficient conditions are given so that for a “large” set of switching laws σ, there exhibits the scrambled dynamics as follows: for all x0,y0∈Rd,x0≠y0,lim infn→+∞∥xn(x0,σ)−xn(y0,σ)∥=0andlim supn→+∞∥xn(x0,σ)−xn(y0,σ)∥=∞.This implies that there coexist positive, zero and negative Lyapunov exponents and that the trajectories (xn(x0, σ))n ≥ 1 are extremely sensitive to the initial states x0∈Rd. We also show that a periodically stable linear inclusion system, which may be product unbounded, does not exhibit any such chaotic behavior. An explicit simple example shows the discontinuity of Lyapunov exponents with respect to the switching laws.","Title: Non-rigid point set registration using dual-feature finite mixture model and global-local structural preservation.\nYear: 2018\n\nAbstract: •We develop a dual-feature finite mixture model based point set registration method.•We define a local structure descriptor.•We constrain the energy function using both the global and local structural regularization terms, preserving the structure at both global and local scales during the registration.•The performance of our method outperforms state-of-art methods in this area.","Title: Interference Alignment in Two-Tier Randomly Distributed Heterogeneous Wireless Networks Using Stochastic Geometry Approach.\nYear: 2018\n\nAbstract: With the massive increase in wireless data traffic in recent years, multi-tier wireless networks have been deployed to provide much higher capacities and coverage. However, heterogeneity of wireless networks bring new challenges for interference analysis and coordination due to spatial randomly distributed transmitters. In this paper, we present a distance-dependent interference alignment (IA) app...","Title: Three-Layer Bayesian Network for Classification of Complex Power Quality Disturbances.\nYear: 2018\n\nAbstract: In this paper, a new classification approach for detection and classification of complex power quality disturbances (PQDs) using a three-level multiply connected Bayesian network is proposed. First, the model consisting of features evidence layer, disturbances state layer, and circumstance evidence layer is established, which represent the features extracted from the sample signal, the state of ea...","Title: Response to Comment on \"All-optical machine learning using diffractive deep neural networks\".\nYear: 2018\n\nAbstract: In their Comment, Wei et al. (arXiv:1809.08360v1 [cs.LG]) claim that our original interpretation of Diffractive Deep Neural Networks (D2NN) represent a mischaracterization of the system due to linearity and passivity. In this Response, we detail how this mischaracterization claim is unwarranted and oblivious to several sections detailed in our original manuscript (Science, DOI: 10.1126/science.aat8084) that specifically introduced and discussed optical nonlinearities and reconfigurability of D2NNs, as part of our proposed framework to enhance its performance. To further refute the mischaracterization claim of Wei et al., we, once again, demonstrate the depth feature of optical D2NNs by showing that multiple diffractive layers operating collectively within a D2NN present additional degrees-of-freedom compared to a single diffractive layer to achieve better classification accuracy, as well as improved output signal contrast and diffraction efficiency as the number of diffractive layers increase, showing the deepness of a D2NN, and its inherent depth advantage for improved performance. In summary, the Comment by Wei et al. does not provide an amendment to the original teachings of our original manuscript, and all of our results, core conclusions and methodology of research reported in Science (DOI: 10.1126/science.aat8084) remain entirely valid.","Title: TasNet: Surpassing Ideal Time-Frequency Masking for Speech Separation.\nYear: 2018\n\nAbstract: Robust speech processing in multitalker acoustic environments requires automatic speech separation. While single-channel, speaker-independent speech separation methods have recently seen great progress, the accuracy, latency, and computational cost of speech separation remain insufficient. The majority of the previous methods have formulated the separation problem through the time-frequency representation of the mixed signal, which has several drawbacks, including the decoupling of the phase and magnitude of the signal, the suboptimality of spectrogram representations for speech separation, and the long latency in calculating the spectrogram. To address these shortcomings, we propose the time-domain audio separation network (TasNet), which is a deep learning autoencoder framework for time-domain speech separation. TasNet uses a convolutional encoder to create a representation of the signal that is optimized for extracting individual speakers. Speaker extraction is achieved by applying a weighting function (mask) to the encoder output. The modified encoder representation is then inverted to the sound waveform using a linear decoder. The masks are found using a temporal convolutional network consisting of dilated convolutions, which allow the network to model the long-term dependencies of the speech signal. This end-to-end speech separation algorithm significantly outperforms previous time-frequency methods in terms of separating speakers in mixed audio, even when compared to the separation accuracy achieved with the ideal time-frequency mask of the speakers. In addition, TasNet has a smaller model size and a shorter minimum latency, making it a suitable solution for both offline and real-time speech separation applications. This study therefore represents a major step toward actualizing speech separation for real-world speech processing technologies.","Title: The Spatial And Temporal Variation Of Land Use In Dianchi Basin Under The Policy Driven By Urban Establishment Up At Mountain\nYear: 2018\n\nAbstract: land use cover change (LUCC) is an important factor affecting the environment as well as a complex process of human activities. Analysis of LUCC has a positive impact on improving the environment. This study analyzed the spatial and temporal distribution of LUCC in Dianchi basin in recent 20 years and use DEM (Digital Elevation Model) data, take advantage of spatial analysis capabilities in ArcGis, Explore the change of LUCC in Dianchi basin on the \"Urban establishment up at mountain \" policy. The results show that in the past 20 years, the LUCC in Dianchi basin is influenced by the environment, but the policy-driven effect is more significant; The amount of land used for urban construction increased by 187.07km(2) at low elevation and 285.79km (2) at low-middle-elevation respectively, and the growth rate of areas at medium and high altitude gradually increased. The woodland (WL) decreases first and then increases, the grassland increases first and then decreases and grassland from boundary moves to the center of the built-up area, and the change amplitude increases; The area of cropland (CL) in the marginal area of Dianchi Lake shows a decreasing trend; All kinds of land conversion relations are complex, but they all show the transformation to urban construction; Urban construction with the \" Urban establishment up at mountain \" policy driven by the apparent low elevation to the high altitude transfer trend, and speed up.","Title: Spatial And Temporal Analysis Of Educational Development In Yunnan On The Last Two Decades\nYear: 2018\n\nAbstract: This paper attempts to find out the space-time law of educational development in different regions by constructing a new method and in the absence of educational quality monitoring system. Based on the analysis of the existing education quality monitoring system, this paper explores and cleans up historical data, and uses the theory of social science research, mathematical statistical analysis and geographic information thinking to study the relevant regions. Research shows that overall education in Yunnan is developing well but there are still improvements in basic education.","Title: Present Situation And Trend Of Remote Sensing Land Use/Cover Classification Extraction\nYear: 2018\n\nAbstract: To further advance the automatic process of land use/cover (LULC) classification extraction through remote sensing (RS) images, by reading many literatures, we summarized the problems, research difficulties and development trends in the process of information extraction and classification of land use. Overall, LULC Classification and extraction based on RS images include 3 tasks: data source selection, sampling design, classification method selection and classifier performance evaluation. These tasks are all important, that is, interdependence and mutual influence. The OBIC method has become a popular method of LULC classification because it makes full use of geographic information system (GIS) technology to process spatial, spectral and textural features in RS images. There are many OBIC algorithms, especially the Machine learning (ML) algorithms offers the potential for effectiveness and efficiency, such as Random forest (RF), Support vector machine (SVM) and so on. The Object-based image classification (OBIC) method involves three stages: segmentation, feature-selection and classification. A large number of studies have proved that there are many problems in each task of the LCLU classification extraction method based on RS images. These problems include design of sample sampling strategy, determination of optimal image segmentation parameters and optimization of parameter of classification algorithm and so on. At present, solving these problems requires frequent human-computer interaction also has a great negative influence on the automatic extraction process of remote sensing classification. Using GIS technology to promote the automatic extraction of remote sensing classification has become a trend of the development of remote sensing classification method.","Title: Study On The Temporal And Spatial Variation Of Pm2.5 In Eight Main Cities Of Yunnan Province\nYear: 2018\n\nAbstract: Air haze pollution has a serious impact on human health, ecological environment and climate change. In recent years, with the introduction of new national policies and people's increasing awareness of environmental protection, haze has received widespread social attention. Haze pollution in China has always been a prominent environmental problem. The main reason for the frequent occurrence of haze pollution is PM2.5, which not only occurs in cities with high degree of industrialization or urbanization, but also often appear in regions with good air quality. This paper selects eight main cities in Yunnan Province as the research area, and uses the measured PM2.5 data from eight main cities in January 2015 to February 2018 in Yunnan Province as the basic data, using the eight urban meteorological data as the basic data, using the MK trend test and Correlation coefficient method to carry out research on the spatial-temporal variation and correlation of PM2.5 in the last three years in Yunnan Province. The space-time analysis shows that the average annual PM2.5 concentration in Lijiang City is the lowest, the monthly average concentration in Baoshan City is the highest, and the daily average concentration in Puer City is in a gentle trend; Except for Lijiang, the other seven cities all experienced different levels of pollution from March 17 to March 26, 2015; The concentration of PM2.5 in each city showed a seasonal pattern of \"U\" and a pulse-like diurnal variation pattern in winter and spring, summer and autumn; cities with higher annual average concentrations in the province are concentrated in the northeast and southwest. Correlation analysis showed that PM2.5 concentration was significantly negatively correlated with precipitation and wind speed, and negatively correlated with daily average humidity and temperature.","Title: Study And Analysis The Spatial Influence Of Intercity Interaction\nYear: 2018\n\nAbstract: In the study of geography, the intensity of interaction between two objects affected by distance is called spatial influence. The study of spatial influence is a concrete description and analysis of spatial interaction problems in the study of geography and regional economics, and it also summarizes analytical methods for spatial influence. According to the Tobler's First Law of Geography, the spatial interaction is affected by distance. Therefore, based on the Gravity Model, this paper discusses the distance decay function to analyze the situation and change of interaction strength between objects under the influence of distance. The field spread model is used to analyze the spatial attractiveness and radiation force of the city. The Breakpoint Theory reflects the specific strength of the intercity connections, especially the attraction of surrounding cities at the Breaking Point. These methods provide theoretical basis for urban regional planning, and have important practical significance for the sustainable development of cities in the future.","Title: Urban Road Image Segmentation Algorithm Based On Statistical Information\nYear: 2018\n\nAbstract: Urban road image segmentation is an important technology of intelligent city management and pilotless driving. In order to improve the effect of image segmentation, direct at the deficiency of single seed point and fixed threshold of traditional region growing algorithm, a seed selection method based on the gray level of two-dimensional histogram and local variance is proposed, and the dynamic threshold is used to change the region growing rule. The experimental results show that the seeds selected by this method can be highly representative, and realize the complete segmentation of the image. Based on the dynamic threshold region growth rule, the image segmentation has a better effect.","Title: Using Sequential Gaussian Simulation to Assess the Spatial Uncertainty of PM<inf>2.5</inf> in China\nYear: 2018\n\nAbstract: Based on the observed PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n concentration data in 2016, ordinary kriging (OK) and sequential Gaussian simulation (SGS) were used to map spatial distribution of PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n in China, and SGS can model not only single, but also multi-location uncertainties, which assess the uncertainty of the PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n spatial distribution. A smoothing effect was produced when using OK technique in mapping of PM2.5, however relatively discrete and fluctuant map was obtained by the SGS. Their results of spatial distribution show that east and west regions have higher PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n concentration, middle regions have lower concentration in China. Based on the SGS realization, the probability that PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n concentration at single location was higher than the defined threshold (10μg/m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n) was big for the whole study area. The minimum value was 0.77. When the defined threshold changed to 35 μg/m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n, the extent of higher probability was shrunk, the bigger value (0.8-1) existed in Xinjiang and North China. The probability which PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n concentrations were higher than the defined threshold in several locations at the same time was also called joint probability. Given the critical probabilities (pm=1 and> 0.98), joint probability of PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n in area a being higher than 10μg/m3 respectively is 0.85 and 0.5; while joint probability of PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\nin area a being higher than 35μg/m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n respectively is 0. 65 and 0.14. The probability map can be very helpful for controlling and making environmental management decision of PM\n<sub xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2.5</sub>\n pollution.","Title: Adversarial Defense of Image Classification Using a Variational Auto-Encoder.\nYear: 2018\n\nAbstract: Deep neural networks are known to be vulnerable to adversarial attacks. This exposes them to potential exploits in security-sensitive applications and highlights their lack of robustness. This paper uses a variational auto-encoder (VAE) to defend against adversarial attacks for image classification tasks. This VAE defense has a few nice properties: (1) it is quite flexible and its use of randomness makes it harder to attack; (2) it can learn disentangled representations that prevent blurry reconstruction; and (3) a patch-wise VAE defense strategy is used that does not require retraining for different size images. For moderate to severe attacks, this system outperforms or closely matches the performance of JPEG compression, with the best quality parameter. It also has more flexibility and potential for improvement via training.","Title: Redesigning a Software Development Course as a Preparation for a Capstone: An Experience Report\nYear: 2019\n\nAbstract: Students need a wide variety of skills before they can successfully engage in real-world projects with paying customers. Some of these skills, such as the \"soft skills\" of communicating with a non-technical customer and working in a larger team to collaboratively develop a project, are generally not present in Computer Science courses. In this paper, we discuss our experience teaching these skills and explain the structure of our redesigned Software Development course and how it aligns with the Capstone experience. The main novelty of our approach is the specific implementation of the rotating project manager role and the introduction of the final portfolio reflection. We believe that the concepts we introduced during our redesign can be useful to any educator wanting to include collaborative project-based work in their courses. To enable faculty to apply and enhance these concepts, the resources that we used in this course, which include activities, templates, guidelines, rubrics, and questionnaires, are available as an open source project at https://team-repo.github.io/.","Title: A fictitious play-based response strategy for multistage intrusion defense systems\nYear: 2014\n\nAbstract: AbstractThe recent developments of advanced intrusion detection systems in the cyber security field provide opportunities to proactively protect the computer network systems and minimize the impacts of attackers on network operations. This paper is intended to assist the network defender find its best actions to defend against multistage attacks. The possible sequences of interactions between the attackers and the network defender are modeled as a two-player non-zero-sum non-cooperative dynamic multistage game with incomplete information. The players are assumed to be rational. They take turns in making decisions by considering previous and possible future interactions with the opponent and use Bayesian analysis after each interaction to update their knowledge about the opponents. We propose a Dynamic game tree-based Fictitious Play DFP approach to describe the repeated interactive decisions of the players. Each player finds its best moves at its decision nodes of the game tree by using multi-objective analysis. All possibilities are considered with their uncertain future interactions, which are based on learning of the opponent's decision process including risk attitude and objectives. Instead of searching the entire game tree, appropriate future time horizons are dynamically determined for both players. In the DFP approach, the defender keeps tracking the opponent's actions, predicts the probabilities of future possible attacks, and then chooses its best moves. Thus, a new defense algorithm, called Response by DFP RDFP, is developed. Numerical experiments show that this approach significantly reduces the damage caused by multistage attacks and it is also more efficient than other related algorithms. Copyright © 2013 John Wiley & Sons, Ltd.","Title: Space Geodetic Observations and Modeling of 2016 Mw 5.9 Menyuan Earthquake: Implications on Seismogenic Tectonic Motion.\nYear: 2016\n\nAbstract: Determining the relationship between crustal movement and faulting in thrust belts is essential for understanding the growth of geological structures and addressing the proposed models of a potential earthquake hazard. A Mw 5.9 earthquake occurred on 21 January 2016 in Menyuan, NE Qinghai Tibetan plateau. We combined satellite interferometry from Sentinel-1A Terrain Observation with Progressive Scans (TOPS) images, historical earthquake records, aftershock relocations and geological data to determine fault seismogenic structural geometry and its relationship with the Lenglongling faults. The results indicate that the reverse slip of the 2016 earthquake is distributed on a southwest dipping shovel-shaped fault segment. The main shock rupture was initiated at the deeper part of the fault plane. The focal mechanism of the 2016 earthquake is quite different from that of a previous Ms 6.5 earthquake which occurred in 1986. Both earthquakes occurred at the two ends of a secondary fault. Joint analysis of the 1986 and 2016 earthquakes and aftershocks distribution of the 2016 event reveals an intense connection with the tectonic deformation of the Lenglongling faults. Both earthquakes resulted from the left-lateral strike-slip of the Lenglongling fault zone and showed distinct focal mechanism characteristics. Under the shearing influence, the normal component is formed at the releasing bend of the western end of the secondary fault for the left-order alignment of the fault zone, while the thrust component is formed at the restraining bend of the east end for the right-order alignment of the fault zone. Seismic activity of this region suggests that the left-lateral strike-slip of the Lenglongling fault zone plays a significant role in adjustment of the tectonic deformation in the NE Tibetan plateau.","Title: A Novel Algorithm For Abandoned Object Detection\nYear: 2016\n\nAbstract: Abandoned object detection is a crucial problem in many computer vision tasks. Traditional method based on foreground/background extraction techniques leads to a high false alarm rate. In this paper, we propose a novel detection algorithm based on change detection and blob separation. Our proposed approach suits more practical scenarios in which objects located near each other. Experiments are conducted on several well-known benchmarks to validate the efficacy of the algorithm proposed in this paper.","Title: A highly accurate and fast power quality disturbances classification based on dictionary learning sparse decomposition\nYear: 2019\n\nAbstract: This paper proposes a highly accurate and fast power quality disturbances (PQDs) classification using dictionary learning sparse decomposition (DLSD). Firstly, an over-complete dictionary is constructed by combining an identity matrix with a learning dictionary trained by K-SVD algorithm. Secondly, the features and the fuzzy primary classifications of PQDs are obtained by calculating the sparse decomposition coefficients based on the learning dictionary. For being adaptive to sparsity and reducing computational complexity, a fast adaptive matching pursuit (FAMP) using sparsity adaptive algorithm and regularized atom selection is proposed. Then, a decision tree is adopted to accomplish accurate classification by using the estimated features and the pre-classification results. Finally, the proposed approach is tested by PQDs from simulations, IEEE PES database and actual measurements. Moreover, several testing signals, which contain strong noise and frequency deviation, are introduced to further validate DLSD. The results demonstrate that DLSD has a good improvement on computational complexity and classification accuracy when dealing with PQDs classification.","Title: Maximized Mutual Information Analysis Based on Stochastic Representation for Process Monitoring\nYear: 2019\n\nAbstract: This paper proposes a stochastic representation of maximized mutual information analysis (MIA) method for quality monitoring in which a manner of imposing prior probability distributions over projection parameters is employed and subsequently, a Bayesian estimation algorithm is put forward for projection learning. The proposed stochastic MIA (SMIA) based approach allows the enhanced performance of fault detection due to the following advantages over classic monitoring methods. First, the SMIA approach utilizes the mechanism of hierarchical priors and an individual prior over each projection direction, as a key feature of the proposed method, which enables SMIA to build a sparse model that can discard irrelevant components in the process data with respect to the prediction of quality variables. Second, the proposed SMIA method incorporates the advantage of maximizing mutual information on the minimum achievable error of model prediction as well as the advantage of describing the serial dynamics. Additionally, the optimal dimensionality of the latent space in an SMIA can be automatically determined during the procedure of Bayesian estimation by the utilization of these adaptive priors over projections. The effectiveness of the proposed approach for quality monitoring is demonstrated on the benchmark of Tennessee Eastman process.","Title: Novel Method Based on Variational Mode Decomposition and a Random Discriminative Projection Extreme Learning Machine for Multiple Power Quality Disturbance Recognition\nYear: 2019\n\nAbstract: Power quality events are usually associated with more than one disturbance and their recognition is typically based on multilabel learning. In this study, we propose a new method for recognizing multiple power quality disturbances (MPQDs) based on variational mode decomposition (VMD) and a random discriminative projection extreme learning machine for multilabel learning (RDPEML). First, VMD is employed to decompose the MPQDs into several intrinsic mode functions and the standard energy differences of each mode are extracted as features that form the input vectors of the classifier. Second, a novel multilabel classifier called RDPEML is constructed by combining a random discriminative projection multiclass extreme learning machine (ELM) and a thresholding learning method-based kernel ELM. In order to obtain better classification performance, a tenfold cross-validation embedded particle swarm optimization approach is utilized to search for the optimal values of the structural parameters. Finally, a test study was conducted using MATLAB synthetic signals and real signals sampled from a three-phase standard source under different noise conditions. Compared with the several recent state-of-the-art multilabel learning algorithms, RDPEML achieved better classification performance with superior computational speed.","Title: Analysis of Diffractive Optical Neural Networks and Their Integration with Electronic Neural Networks.\nYear: 2018\n\nAbstract: Optical machine learning offers advantages in terms of power efficiency, scalability, and computation speed. Recently, an optical machine learning method based on diffractive deep neural networks (D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNNs) has been introduced to execute a function as the input light diffracts through passive layers, designed by deep learning using a computer. Here, we introduce improvements to D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNNs by changing the training loss function and reducing the impact of vanishing gradients in the error back-propagation step. Using five phase-only diffractive layers, we numerically achieved a classification accuracy of 97.18% and 89.13% for optical recognition of handwritten digits and fashion products, respectively; using both phase and amplitude modulation (complex-valued) at each layer, our inference performance improved to 97.81% and 89.32%, respectively. Furthermore, we report the integration of D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNNs with electronic neural networks to create hybrid classifiers that significantly reduce the number of input pixels into an electronic network using an ultra-compact front-end D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNN with a layer-to-layer distance of a few wavelengths, also reducing the complexity of the successive electronic network. Using a five-layer phase-only D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNN jointly optimized with a single fully connected electronic layer, we achieved a classification accuracy of 98.71% and 90.04% for the recognition of handwritten digits and fashion products, respectively. Moreover, the input to the electronic network was compressed by >7.8 times down to 10 × 10 pixels. Beyond creating low-power and high-frame rate machine learning platforms, D\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">2</sup>\nNN-based hybrid neural networks will find applications in smart optical imager and sensor design.","Title: Online Deep Attractor Network for Real-time Single-channel Speech Separation\nYear: 2019\n\nAbstract: Speaker-independent speech separation is a challenging audio processing problem. In recent years, several deep learning algorithms have been proposed to address this problem. The majority of these methods use noncausal implementation which limits their application in real-time scenarios such as in wearable hearing devices and low-latency telecommunication. In this paper, we propose the Online Deep Attractor Network (ODANet), an extension to the Deep Attractor Network (DANet) which is causal and enables real-time speech separation. In contrast with DANet that estimates the global attractor point for each speaker using the entire utterance, ODANet estimates the attractors for each time step and tracks them using a dynamic weighting function with only causal information. This not only solves the speaker tracking problem, but also allows ODANet to generate more stable embeddings across time. Experimental results show that ODANet can achieve a similar separation accuracy as the noncausal DANet in both two speaker and three speaker speech separation problems, which makes it a suitable candidate for applications that require robust real-time speech processing.","Title: Dynamic Demand Prediction for Expanding Electric Vehicle Sharing Systems: A Graph Sequence Learning Approach.\nYear: 2019\n\nAbstract: Electric Vehicle (EV) sharing systems have recently experienced unprecedented growth across the globe. During their fast expansion, one fundamental determinant for success is the capability of dynamically predicting the demand of stations as the entire system is evolving continuously. There are several challenges in this dynamic demand prediction problem. Firstly, unlike most of the existing work which predicts demand only for static systems or at few stages of expansion, in the real world we often need to predict the demand as or even before stations are being deployed or closed, to provide information and support for decision making. Secondly, for the stations to be deployed, there is no historical record or additional mobility data available to help the prediction of their demand. Finally, the impact of deploying/closing stations to the remaining stations in the system can be very complex. To address these challenges, in this paper we propose a novel dynamic demand prediction approach based on graph sequence learning, which is able to model the dynamics during the system expansion and predict demand accordingly. We use a local temporal encoding process to handle the available historical data at individual stations, and a dynamic spatial encoding process to take correlations between stations into account with graph convolutional neural networks. The encoded features are fed to a multi-scale prediction network, which forecasts both the long-term expected demand of the stations and their instant demand in the near future. We evaluate the proposed approach on real-world data collected from a major EV sharing platform in Shanghai for one year. Experimental results demonstrate that our approach significantly outperforms the state of the art, showing up to three-fold performance gain in predicting demand for the rapidly expanding EV sharing system.","Title: Three-Dimensional Computed Tomography Angiography Assisted Resection of Ventral Foramen Magnum and Jugular Foramen Tumours via Modified Far Lateral Suboccipital Approach\nYear: 2019\n\nAbstract: Objective: The anatomical relationship of ventral foramen magnum and jugular foramen tumour is complex and the operation is very difficult. The aim of this study was to summarize the microsurgical experience of the removal of the ventral foramen magnum and jugular foramen tumours via the modified far lateral suboccipital approach assisted by three-dimensional computed tomography angiography (3D-CTA). Methods: The clinical data and follow-up results of 13 cases of 3D-CTA assisted suboccipital far lateral approach from July 2011 to September 2017 were analyzed retrospectively. There were 5 males and 8 females. Preoperative CT and MRI were used for routine imaging diagnosis, and the 3D-CTA simulated surgical approach was performed. The preoperative operation scheme was established, and the risk of operation was evaluated according simulated operation. After individualized exposure, the modified far lateral suboccipital approach was completed under the neuroelectrophysiological monitoring technique. Results: The preoperative images were completely consistent with the findings in the surgery. There were 9 cases of jugular foramen tumour and 4 cases of ventral foramen magnum tumour. Of the 13 cases, only 1 case of jugular glomus tumour had extra-cranial residual, while the whole intracranial tumour was removed. In other 12 cases, the tumours were completely removed under the microscope. After operation, the headache disappeared, and hearing loss was improved. There was no perioperative deaths, infection and cerebrospinal fluid leakage. The facial paralysis was occurred in 1 patient. After 3-39 months of follow-up, there was no recurrence of tumour, or new nerve function defect. Hoarseness, choking of drinking water and numbness of limbs were all improved at the end of the follow-up period. The symptoms of postoperative facial paralysis were also improved during the follow-up period. Conclusion: After the preoperative simulation and evaluation by 3D-CTA, the ventral foramen magnum and jugular foramen tumours can be rescted safely and effectively via far modified lateral suboccipital approach.","Title: Augmented Time-Frequency Mask Estimation In Cluster-Based Source Separation Algorithms\nYear: 2019\n\nAbstract: Time-frequency mask estimation with various clustering approaches has proven effective in solving the audio source separation problem. In this framework, the time-frequency bins of the mixture spectrogram are represented in a high-dimensional embedding space, where various methods can be applied to group the embedded points to calculate either hard or soft source assignments and subsequently the time-frequency masks. However, the mismatch between the assignment algorithm during the training and inference phases in majority of the current approaches leads to a suboptimal solution, because the assignment objective that is used during the training (e.g. ideal binary mask) is not the same as the one used during the inference phase (e.g. k-means clustering). We propose a method to reduce the mismatch between these two conditions where the source embedding is trained such that the source assignment during training and inference phases results in similar outcomes. Our results show that matching the source assignment during training-and inference-phase results in more accurate and consistent mask estimation in the inference phase which significantly improves the source separation accuracy for various hard and soft clustering methods.","Title: Class-Specific Differential Detection In Diffractive Optical Neural Networks Improves Inference Accuracy\nYear: 2019\n\nAbstract: Optical computing provides unique opportunities in terms of parallelization, scalability, power efficiency, and computational speed and has attracted major interest for machine learning. Diffractive deep neural networks have been introduced earlier as an optical machine learning framework that uses task-specific diffractive surfaces designed by deep learning to all-optically perform inference, achieving promising performance for object classification and imaging. We demonstrate systematic improvements in diffractive optical neural networks, based on a differential measurement technique that mitigates the strict nonnegativity constraint of light intensity. In this differential detection scheme, each class is assigned to a separate pair of detectors, behind a diffractive optical network, and the class inference is made by maximizing the normalized signal difference between the photodetector pairs. Using this differential detection scheme, involving 10 photodetector pairs behind 5 diffractive layers with a total of 0.2 million neurons, we numerically achieved blind testing accuracies of 98.54%, 90.54%, and 48.51% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively. Moreover, by utilizing the inherent parallelization capability of optical systems, we reduced the cross-talk and optical signal coupling between the positive and negative detectors of each class by dividing the optical path into two jointly trained diffractive neural networks that work in parallel. We further made use of this parallelization approach and divided individual classes in a target dataset among multiple jointly trained diffractive neural networks. Using this class-specific differential detection in jointly optimized diffractive neural networks that operate in parallel, our simulations achieved blind testing accuracies of 98.52%, 91.48%, and 50.82% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively, coming close to the performance of some of the earlier generations of all-electronic deep neural networks, e.g., LeNet, which achieves classification accuracies of 98.77%, 90.27%, and 55.21% corresponding to the same datasets, respectively. In addition to these jointly optimized diffractive neural networks, we also independently optimized multiple diffractive networks and utilized them in a way that is similar to ensemble methods practiced in machine learning; using 3 independently optimized differential diffractive neural networks that optically project their light onto a common output/detector plane, we numerically achieved blind testing accuracies of 98.59%, 91.06%, and 51.44% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively. Through these systematic advances in designing diffractive neural networks, the reported classification accuracies set the state of the art for all-optical neural network design. The presented framework might be useful to bring optical neural network-based low power solutions for various machine learning applications and help us design new computational cameras that are task-specific.","Title: Conv-TasNet: Surpassing Ideal Time-Frequency Magnitude Masking for Speech Separation\nYear: 2019\n\nAbstract: Single-channel, speaker-independent speech separation methods have recently seen great progress. However, the accuracy, latency, and computational cost of such methods remain insufficient. The majority of the previous methods have formulated the separation problem through the time–frequency representation of the mixed signal, which has several drawbacks, including the decoupling of the phase and magnitude of the signal, the suboptimality of time–frequency representation for speech separation, and the long latency in calculating the spectrograms. To address these shortcomings, we propose a fully convolutional time-domain audio separation network Conv-TasNet, a deep learning framework for end-to-end time-domain speech separation. Conv-TasNet uses a linear encoder to generate a representation of the speech waveform optimized for separating individual speakers. Speaker separation is achieved by applying a set of weighting functions masks to the encoder output. The modified encoder representations are then inverted back to the waveforms using a linear decoder. The masks are found using a temporal convolutional network consisting of stacked one-dimensional dilated convolutional blocks, which allows the network to model the long-term dependencies of the speech signal while maintaining a small model size. The proposed Conv-TasNet system significantly outperforms previous time–frequency masking methods in separating two- and three-speaker mixtures. Additionally, Conv-TasNet surpasses several ideal time–frequency magnitude masks in two-speaker speech separation as evaluated by both objective distortion measures and subjective quality assessment by human listeners. Finally, Conv-TasNet has a significantly smaller model size and a shorter minimum latency, making it a suitable solution for both offline and real-time speech separation applications. This study, therefore, represents a major step toward the realization of speech separation systems for real-world speech processing technologies.","Title: ComQA: Question Answering over Knowledge Base via Semantic Matching\nYear: 2019\n\nAbstract: Question answering over knowledge base (KBQA) is a powerful tool to extract answers from graph-like knowledge bases. Here, we present ComQA-a three-phase KBQA framework by which end-users can ask complex questions and get answers in a natural way. In ComQA, a complex question is decomposed into several triple patterns. Then, ComQA retrieves candidate subgraphs matching the triple patterns from the knowledge base and evaluates the semantic similarity between the subgraphs and the triple patterns to find the answer. It is a long-standing problem to evaluate the semantic similarity between the question and the heterogeneous subgraph containing the answer. To handle this problem, first, a semantic-based extension method is proposed to identify entities and relations in the question while considering the underlying knowledge base. The precision of identifying entities and relations determines the correctness of successive steps. Second, by exploiting the syntactic pattern in the question, ComQA constructs the query graphs for natural language questions so that it can filter out topology-mismatch subgraphs and narrow down the search space in knowledge bases. Finally, by incorporating the information from the underlying knowledge base, we fine-tune general word vectors, making them more specific to ranking possible answers in KBQA task. Extensive experiments over a series of QALD challenges confirm that the performance of ComQA is comparable to those state-of-the-art approaches with respect to precision, recall, and F1-score.","Title: An Energy-Efficient Clustering Routing Protocol Based on a High-QoS Node Deployment with an Inter-Cluster Routing Mechanism in WSNs.\nYear: 2019\n\nAbstract: Currently, wireless sensor network (WSN) protocols are mainly used to achieve low power consumption of the network, but there are few studies on the quality of services (QoS) of these networks. Coverage can be used as a measure of the WSN's QoS, which can further reflect the quality of data information. Additionally, the coverage requirements of regional monitoring target points are different in real applications. On this basis, this paper proposes an energy-efficient clustering routing protocol based on a high-QoS node deployment with an inter-cluster routing mechanism (EECRP-HQSND-ICRM) in WSNs. First, this paper proposes formula definitions for information integrity, validity, and redundancy from the coverage rate and introduces a node deployment strategy based on twofold coverage. Then, in order to satisfy the uniformity of the distribution of cluster heads (CHs), the monitoring area is divided into four small areas centered on the base station (BS), and the CHs are selected in the respective cells. Finally, combined with the practical application of the WSN, this paper optimizes the Dijkstra algorithm, including: (1) nonessential paths neglecting considerations, and (2) a simultaneous introduction of end-to-end weights and path weights, achieving the selection of optimal information transmission paths between the CHs. The simulation results show that, compared with the general node deployment strategies, the deployment strategy of the proposed protocol has higher information integrity and validity, as well as lower redundancy. Meanwhile, compared with some classic protocols, this protocol can greatly reduce and balance network energy consumption and extend the network lifetime.","Title: Improved Alarm Visualization System Based on Two-Dimensional Online Root-cause Contribution Graph for Industry 4.0\nYear: 2019\n\nAbstract: Process industry has entered a period of rapid development, and industrial safety is an eternal theme of industry 4.0. With the development of industry 4.0, the generation of a large amount of process data provides a research basis for process monitoring. The data-driven process monitoring algorithm sharply finds the abnormal value of the process by analyzing the data of normal condition. Different from the traditional alarm method and principal component analysis (PCA) contribution graph method, the Two-Dimensional Online Root-cause Contribution Graph (2D-ORCG) proposed in this paper is based on the traditional PCA method. Capturing information by the online root-cause variable visualization strategy proposed in this paper. Contribution analysis based on dynamic data can more effectively capture the key variables that affect the stability of the system, and also can accurately capture different variables at different times. Comparing to the traditional Two-Dimensional Contribution Graph method, the effectiveness of the 2D-ORCG method is demonstrated on the Tennessee Eastman Process (TEP).","Title: Intelligent modeling using a novel feature extraction based multiple activation functions extreme learning machine\nYear: 2019\n\nAbstract: For industry 4.0, intelligent modeling is very important. Modelling plays a very important role in making control strategies and production plans. Nevertheless, establishing an accurate and robust model becomes more difficult because of the increasing complexity of modelling data. To solve this problem, a novel feature extraction based multiple activation functions extreme learning machine (LV-MAFELM) is presented. The LV-MAFELM model is easy to construct: firstly, generate the input weights at random; secondly, select several different nonlinear activation functions and compute the hidden layer outputs; thirdly, extract principal components from the hidden layer outputs; finally, compute the output weights analytically. For verifying the model performance, the LV-MAFELM model is applied in one petrochemical industry process -the Purified Terephthalic Acid (PTA) process. Simulation results demonstrate that the presented LV-MAFELM achieves good performance, which indicates that accuracy and stability of energy prediction models can be improved.","Title: Dual-Path Rnn For Long Recording Speech Separation\nYear: 2021\n\nAbstract: Continuous speech separation (CSS) is an arising task in speech separation aiming at separating overlap-free targets from a long, partially-overlapped recording. A straightforward extension of previously proposed sentence-level separation models to this task is to segment the long recording into fixed-length blocks and perform separation on them independently. However, such simple extension does not fully address the cross-block dependencies and the separation performance may not be satisfactory. In this paper, we focus on how the block-level separation performance can be improved by exploring methods to utilize the cross-block information. Based on the recently proposed dual-path RNN (DPRNN) architecture, we investigate how DPRNN can help the block-level separation by the interleaved intra- and inter-block modules. Experiment results show that DPRNN is able to significantly outperform the baseline block-level model in both offline and block-online configurations under certain settings.","Title: Ultra-wide Bandwidth Thin-film LiNbO3 Modulator with Record-Low Half-wave-voltage Length Product\nYear: 2021\n\nAbstract: Novel electro-optic modulators are fabricated based on LiNbO3-silica hybrid waveguide and capacitively-loaded electrodes. Record-low half-wave-voltage length product of 1.7 V.cm and modulation bandwidth > 67 GHz are demonstrated. (C) 2021 The Author(s)","Title: The heat exchange process between surface water and near-surface atmosphere in the front of the Three Gorges Dam\nYear: 2021\n\nAbstract: •The Three Gorges Dam conceals the increase in air temperature.•The surface water temperature and air temperature have seasonal changes due to the dam.•The Three Gorges Dam affects the heat exchange of water-air interface.","Title: Spatial Variations In Terrestrial Water Storage With Variable Forces Across The Yellow River Basin\nYear: 2021\n\nAbstract: Terrestrial water storage (TWS) variations are a result of the interconnected impact of various variables including climate, hydrology, ecology, and anthropogenic activities. Previous studies have indicated that climate factors (e.g., precipitation and potential evapotranspiration), vegetation restoration, and water withdrawals (irrigational and industrial water use) are the major determinants of TWS depletion across the Yellow River Basin (YRB). However, few studies have provided explicit information about the main forcing variables that determine spatiotemporal variations in TWS and the synergies among these factors. This study explored the explicit understanding of hydro-climatic and socio-ecological determinants and the key interacting processes that affected the TWS variations across the Yellow River Basin in northern China. The multivariate adaptive regression splines model was employed to establish the relationship function of the long-term trends for the dependent (TWS) and independent (explanatory) variables consisting of normalized difference vegetation index (NDVI), hydro-climate, and human water withdrawal. The long-term trends estimated from the MARS model reproduced the ones calculated by Gravity Recovery and Climate Experiment gravity satellites, with a determination coefficient (R-2) of 0.83 and a mean absolute error (MAE) of 1.2 mm. The results showed that precipitation, minimum temperature, runoff, base flow, water withdrawal for electricity, and NDVI were the main drivers of the spatiotemporal variations in the TWS, of which minimum temperature and runoff played a considerable role in TWS variations through the interplay with other variables. The critical values of the trend for interactive variables, which could alter the acting direction of the synergy on the TWS, were also estimated. In view of the connotation of interactive variables, we suggested that spatiotemporal variations in TWS resulted from the coupling of the hydrological energy system, hydrological ecosystem, and hydrological system in the YRB, of which the hydrological system plays the most significant role, followed by the hydrological ecosystem.","Title: Progressive anatomically constrained deep neural network for 3D deformable medical image registration\nYear: 2021\n\nAbstract: The 3D deformable image registration is one of the most challenging tasks in medical image analysis. Due to the large and complex deformation in 3D medical images, many deep neural network based methods have been proposed to improve the image similarity after registration, among which recursive cascading network structure is one of the state-of-the-art. However, most existing works rely on the pixel-level image similarities to achieve anatomical rationality and overlook the global-level resemblance between the two structures. Therefore, the resulting registration is not quite clinically valuable. To this end, in this work, we propose a Progressive Anatomically Constrained deep neural Network (PACN) to incorporate the anatomical priors into a progressive cascading registration network to improve the anatomical plausibility as well as the pixel-level similarity of the registration results. Specifically, an Anatomical Constraint Encoder (ACE) network is proposed to encode the global context of the anatomical segmentations and attached to the dense registration network to form a registration unit. Repeated such units forming a cascading framework progressively warps the moving image toward the fixed one, with the output warped image of one unit as the input of the next unit. In this design, the global anatomical priors along with the pixel-level local information are used to guide the model learning process to produce high quality deformation field. Based on this, we explore two frameworks to investigate their registration effectiveness, one attaches the anatomical constraint encoder (ACE) to every dense registration sub-network and the other one attaches ACE only to the last dense registration unit. We test the two frameworks on benchmarks of three liver image datasets SLIVER, LiTS and LSPIG, and one brain dataset LPBA. Our two frameworks have achieved significantly better results in terms of average Dice score than the state-of-the-art baseline method on three liver datasets and comparable on LPBA when both tested with up to three cascades.","Title: A cascaded registration network RCINet with segmentation mask\nYear: 2021\n\nAbstract: Traditional deformable registration methods achieve brilliant results and show strong theoretical support but are computational intensive since they optimize each image pair's objective function. Recently, supervised learning methods have facilitated fast registration. However, it requires ground truth and does not guarantee a diffeomorphism registration. This paper proposes a new unsupervised learning method Recursive Cascaded Network with a segmentation mask, for two-dimensional medical image registration. Different from the original cascaded network, the network framework into two parts. The first section obtains a pair of image rolls and uses the registration sub-network to predict the deformation vector field from the moving image to the fixed image. The second part introduces anatomical segmentation into the network during training, makes full use of the auxiliary information of the volume, adds an autoencoder to encode the anatomical segmentation, and incorporates it into the learning process of the model in the form of constraints. The local and global ideas are combined to ensure the deformation field's rationality and improve the distribution. The most important thing is that we propose a formula for calculating the cascaded network's deformation field used in the test stage to evaluate the relationship between the registration accuracy and the deformation field's effectiveness. Our experiments show that the system has a better registration effect and less information loss than the current state-of-the-art method. Simultaneously, the cascade method's accuracy is an improvement at a certain number of layers, and the increase in accuracy needs to sacrifice the effectiveness of the deformation field.","Title: From gratitude to injustice: Neurocomputational mechanisms of gratitude-induced injustice\nYear: 2021\n\nAbstract: Gratitude shapes individuals’ behaviours and impacts the harmony of society. Many previous studies focused on its association with prosocial behaviours. A possibility that gratitude can lead to moral violation has been overlooked until recently. Nevertheless, the neurocognitive mechanisms of gratitude-induced moral violation are still unclear. On the other hand, though neural correlates of the gratitude's formation have been examined, the neural underpinnings of gratitude-induced behaviour remain unknown. For addressing these two overlapped research gaps, we developed novel tasks to investigate how participants who had received voluntary (Gratitude group) or involuntary help (Control group) punished their benefactors’ unfairness with functional magnetic resonance imaging (fMRI). The Gratitude group punished their benefactors less than the Control group. The self-report and computational modelling results demonstrated a crucial role of the boosted protection tendency on behalf of benefactors in the gratitude-induced injustice. The fMRI results showed that activities in the regions associated with mentalizing (temporoparietal junction) and reward processing (ventral medial prefrontal cortex) differed between the groups and were related to the gratitude-induced injustice. They suggest that grateful individuals concern for benefactors’ benefits, value chances to interact with benefactors, and refrain from action that perturbs relationship-building (i.e., exert less punishment on benefactors’ unfairness), which reveal a dark side of gratitude and enrich the gratitude theory (i.e., the find-bind-remind theory). Our findings provide psychological, computational, and neural accounts of the gratitude-induced behaviour and further the understanding of the nature of gratitude.","Title: Hierarchical Authorization Of Convolutional Neural Networks For Multi-User\nYear: 2021\n\nAbstract: Convolutional neural networks (CNNs) are widely used in many aspects and achieve excellent results. Due to the authorization from different users, we need to consider the right management caused by multi-user. This paper proposes a novel concept of hierarchical authorization of CNNs, and it can help owners control the output results according to accesses. To realize this idea, we refer to differential privacy and use the Laplace mechanism to perturb the output of the model to vary degrees. In experiments, we run on CIFAR-10 and MNIST datasets using ResNet and VGG, and the results show our method has significant grading effects.","Title: Speech Separation Using an Asynchronous Fully Recurrent Convolutional Neural Network.\nYear: 2021\n\nAbstract: Recent advances in the design of neural network architectures, in particular those specialized in modeling sequences, have provided significant improvements in speech separation performance. In this work, we propose to use a bio-inspired architecture called Fully Recurrent Convolutional Neural Network (FRCNN) to solve the separation task. This model contains bottom-up, top-down and lateral connections to fuse information processed at various time-scales represented by stages. In contrast to the traditional approach updating stages in parallel, we propose to first update the stages one by one in the bottom-up direction, then fuse information from adjacent stages simultaneously and finally fuse information from all stages to the bottom stage together. Experiments showed that this asynchronous updating scheme achieved significantly better results with much fewer parameters than the traditional synchronous updating scheme on speech separation. In addition, the proposed model achieved competitive or better results with high efficiency as compared to other state-of-the-art approaches on two benchmark datasets.","Title: Computational anti-COVID-19 drug design: progress and challenges\nYear: 2022\n\nAbstract: Vaccines have made gratifying progress in preventing the 2019 coronavirus disease (COVID-19) pandemic. However, the emergence of variants, especially the latest delta variant, has brought considerable challenges to human health. Hence, the development of robust therapeutic approaches, such as anti-COVID-19 drug design, could aid in managing the pandemic more efficiently. Some drug design strategies have been successfully applied during the COVID-19 pandemic to create and validate related lead drugs. The computational drug design methods used for COVID-19 can be roughly divided into (i) structure-based approaches and (ii) artificial intelligence (AI)-based approaches. Structure-based approaches investigate different molecular fragments and functional groups through lead drugs and apply relevant tools to produce antiviral drugs. AI-based approaches usually use end-to-end learning to explore a larger biochemical space to design antiviral drugs. This review provides an overview of the two design strategies of anti-COVID-19 drugs, the advantages and disadvantages of these strategies and discussions of future developments.","Title: Data-Domain Traveltime Inversion of Reflected Waves Using Segment Dynamic Image Warping\nYear: 2022\n\nAbstract: Reflection traveltime information is generally used for producing a kinematically accurate velocity model for seismic imaging. Accurately estimating the traveltime difference between the demigrated and observed data is crucial for data-domain reflection traveltime tomography. To enhance the robustness of signal's alignment, we propose a new method of segment dynamic image warping (SDIW). It first exploits windowed polynomial fitting for signal processing and then aligns the signals based on point-wise segment-to-segment matching. Compared with the conventional point-to-point matching strategy, our method is more robust and insensitive toward strong random noise. By minimizing the traveltime difference computed by SDIW, data-domain reflection traveltime inversion (DRTI) is then used to find an accurate background velocity model. Synthetic tests show that SDIW provides reliable time shifts between the demigrated and observed data even if the signal-to-noise ratio of input data is rather low. This enables DRTI to automatically reconstruct the deep background velocity model. The subsequent full waveform inversion (FWI) gradually added short-wavelength velocity structures and finally recovers a high-resolution and high-fidelity model. The results demonstrate that the DRTI provides a kinematically accurate background velocity model sufficient for following FWI to fully retrieve the detail of the subsurface structures even when the low frequencies are missing.","Title: A multi-task graph convolutional network modeling of drug-drug interactions and synergistic efficacy\nYear: 2021\n\nAbstract: Identification of drug-drug interaction(DDI) is critical for safer and more effective drug co-prescription. As wetlab screening assays are time-consuming, labor-intensive and expensive, it is highly desired to develop an effective computational method to predict drug-drug interactions. In this work, we aim to predict of drug-drug interactions and synergistic drug combinations by proposing an end-t...","Title: GCNSDA: Predicting snoRNA-disease associations via graph convolutional network\nYear: 2021\n\nAbstract: Small nucleolar RNAs(snoRNAs) represent an abundant group of noncoding RNAs in the nucleolus of eukaryotes. Recent studies revealed that snoRNAs play a significant role in a wide range of diseases. Identifying snoRNA-disease associations can provide great insights into understanding the disease and treatment and boosting drug discovery development. Traditional methods of using biological experimen...","Title: ClawGAN: Claw connection-based generative adversarial networks for facial image translation in thermal to RGB visible light\nYear: 2022\n\nAbstract: •ClawGAN for Thermal-Visible facial image translation is proposed.•We propose the Mismatch metric (MM) to measure mapping relationship of paired images.•We introduce the generative reconstructed loss and the synthesized loss to full objective.•The claw connection network architecture are used as the generator of GAN.","Title: Node Representation Learning in Graph via Node-to-Neighbourhood Mutual Information Maximization\nYear: 2022\n\nAbstract: The key towards learning informative node representations in graphs lies in how to gain contextual information from the neighbourhood. In this work, we present a simple-yet-effective self-supervised node representation learning strategy via directly maximizing the mutual information between the hidden representations of nodes and their neighbourhood, which can be theoretically justified by its link to graph smoothing. Following InfoNCE, our framework is optimized via a surrogate contrastive loss, where the positive selection underpins the quality and efficiency of rep-resentation learning. To this end, we propose a topology-aware positive sampling strategy, which samples positives from the neighbourhood by considering the structural dependencies between nodes and thus enables positive selection upfront. In the extreme case when only one positive is sampled, we fully avoid expensive neighbourhood aggregation. Our methods achieve promising performance on various node classification datasets. It is also worth mentioning by applying our loss function to MLP based node encoders, our methods can be orders of faster than existing solutions. Our codes and supplementary materials are available at https://github.com/dongwei156/n2n.","Title: First Arrival Traveltime Picking Through 3-D U-Net\nYear: 2022\n\nAbstract: In seismic exploration, picking first arrival traveltimes is an important step toward the estimation of subsurface velocity model, which has the direct impact on the well placement. In this letter, we present a 3-D deep learning method for automatic picking. In specific, we employ a supervised 3-D U-shaped full-convolutional network (3-D U-Net) to classify each sample in the 3-D seismic data into two categories: samples before and after the first break. Subsequently, we delineate a surface to separate these two categories, and such surface is corresponding to the desired first arrival traveltimes. In our training phase, besides the original normalized waveform data, we include the energy semblance feature as a channel of the input data, which helps to involve human understanding. The trained 3-D U-Net is applied to both synthetic and real datasets. The synthetic test shows that even if the labels contain some outliers, the predictions are still stable and reasonable in the sense that 3-D U-Net is capable of correcting some incorrect pickings. As for the field dataset test, the predicted results of 3-D U-Net are satisfactory based on human visual verification, and the picked traveltime surface is more consistent compared with the one predicted by the 2-D U-Net.","Title: On the Use of Deep Mask Estimation Module for Neural Source Separation Systems\nYear: 2022\n\nAbstract: Most of the recent neural source separation systems rely on a masking-based pipeline where a set of multiplicative masks are estimated from and applied to a signal representation of the input mixture. The estimation of such masks, in almost all network architectures, is done by a single layer followed by an optional nonlinear activation function. However, recent literatures have investigated the use of a deep mask estimation module and observed performance improvement compared to a shallow mask estimation module. In this paper, we analyze the role of such deeper mask estimation module by connecting it to a recently proposed unsupervised source separation method, and empirically show that the deep mask estimation module is an efficient approximation of the so-called overseparation-grouping paradigm with the conventional shallow mask estimation layers.","Title: A 30-fps 192 × 192 CMOS Image Sensor With Per-Frame Spatial-Temporal Coded Exposure for Compressive Focal-Stack Depth Sensing\nYear: 2022\n\nAbstract: In this article, we present a CMOS image sensor (CIS) for coded-exposure-based compressive focal-stack imaging. The proposed CIS has a pixel design, which includes two capacitive trans-impedance amplifiers (CTIAs) and a static random access memory (SRAM), and is capable of per-frame exposure encoding with adjustable spatiotemporal resolutions. A proof-of-concept CIS prototype with a 192 \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\times $ </tex-math></inline-formula>\n 192 pixel array is designed and fabricated in a 0.13-\n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\mu \\text{m}$ </tex-math></inline-formula>\n CMOS process with a pixel size of 12.6 \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\times $ </tex-math></inline-formula>\n 12.6 \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"> <tex-math notation=\"LaTeX\">$\\mu \\text{m}^{2}$ </tex-math></inline-formula>\n. Operating at 30 frames per second (fps), the CIS demonstrates spatial–temporal coded exposure at a maximum rate of 768 masks/frame. The column-wise 10-bit single-slope (SS) analog-to-digital converter (ADC) includes a ramp-slope adaptation feature used for power optimization. During a frame of coded exposure, a linear focal sweep is implemented by a voice-coil motor (VCM) lens mounted in front of the proposed CIS. Through the sparse reconstruction of the coded image, a focal stack consisting of a volume of defocused images is used to synthesize the scene depth map. By introducing coded exposure, the proposed on-chip compressive focal-stack imaging approach facilitates a frame-saving method for passive depth sensing in machine vision and other imaging applications.","Title: A Highly Compact Thin-film Lithium Niobate Modulator with Low Half-wave Voltage\nYear: 2022\n\nAbstract: Meandered thin-film lithium niobate modulators with capacitively loaded travelling-wave electrodes are demonstrated. Interdigitated T-rails are employed for reversed electric field, resulting in 1.08 V half-wave voltage and 3-dB bandwidth beyond 50 GHz for 8-mm-long devices. (C) 2022 The Author(s)","Title: Evaluating the potential of H8/AHI geostationary observations for monitoring vegetation phenology over different ecosystem types in northern China\nYear: 2022\n\nAbstract: •Different strategies for compositing daily EVI2 from 10-min AHI data were assessed.•Mean value compositing using data around solar noon minimized anisotropic effects.•Composited AHI daily EVI2 time series have 5.3 times more observations than MODIS.•Phenology dates were successfully retrieved from composited AHI EVI2 time series.•AHI can reduce uncertainty in phenology monitoring with more valid data and less gaps.","Title: Review on the Change Trend, Attribution Analysis, Retrieval, Simulation, and Prediction of Lake Surface Water Temperature\nYear: 2022\n\nAbstract: Lake surface water temperature (LSWT) is indicative of changes in climate and geomorphology. It has been found that LSWT has shown faster warming than air temperature in recent decades, which has greatly affected the aquatic ecosystem of lakes and even led to ecological collapse. It was mainly caused by climate warming and geomorphological changes caused by human activities. However, lakes with different properties respond differently to these changes, resulting in temporal and spatial heterogeneity in the changes of LSWT. After an extensive literature review, it was found that the research on LSWT is mainly focused on the following aspects: 1) qualitative or quantitative analysis of natural and anthropogenic factors affecting LSWT changes; 2) impacts of LSWT changes on lake ecology; 3) acquisition of LSWT data, such as retrieval based on remote sensing imagery, model-based simulation prediction; and 4) study of temporal and spatial variation characteristics of LSWT long time series. Dynamically monitoring LSWT changes, predicting, and quantifying the response of lakes with different properties to abrupt or gradual climate changes and changes in human activity intensity, can inform modeling of ecosystem response processes and long-term management planning of large freshwater ecosystems. Therefore, this article provides a systematic review of LSWT from the above four aspects to provide empirical insight and methodological reference for conducting LSWT research.","Title: A Time-Domain Real-Valued Generalized Wiener Filter for Multi-Channel Neural Separation Systems\nYear: 2022\n\nAbstract: Frequency-domain beamformers have been successful in a wide range of multi-channel neural separation systems in the past years. However, the operations in conventional frequency-domain beamformers are typically independently-defined and complex-valued, which result in two drawbacks: the former does not fully utilize the advantage of end-to-end optimization, and the latter may introduce numerical instability during the training phase. Motivated by the recent success in end-to-end neural separation systems, in this paper we propose time-domain real-valued generalized Wiener filter (TD-GWF), a linear filter defined on a 2-D learnable real-valued signal transform. TD-GWF splits the transformed representation into groups and performs an minimum mean-square error (MMSE) estimation on all available channels on each of the groups. We show how TD-GWF can be connected to conventional filter-and-sum beamformers when certain signal transform and the number of groups are specified. Moreover, given the recent success in the sequential neural beamforming frameworks, we show how TD-GWF can be applied in such frameworks to perform iterative beamforming and separation to obtain an overall performance gain. Comprehensive experiment results show that TD-GWF performs consistently better than conventional frequency-domain beamformers in the sequential neural beamforming pipeline with various neural network architectures, microphone array scenarios, and task configurations.","Title: Simulation and Experimental Study on Vacuum Negative Pressure Infusion of Working Fluid for Micro Heat Pipes\nYear: 2022\n\nAbstract: Optimum filling ratio as an important parameter has a great effect on the heat performance of heat pipes. Especially for micro heat pipes with only hundreds of microliters of internal volume, their optimum filling ratios are hard to be obtained without the filling accuracy of an order of microliter magnitude. This paper simulated the filling process of water as the working fluid, and the change regularities of the pressure, the velocity and the volume fraction of liquid water were investigated. The simulation results show that the flow pattern of plug flow is the key to leading to the infusion error. The liquid-vapor slugs caused the pulsation of pressure and velocity, which would make the flow flux uncontrollable accurately. The maximum relative error in simulated filling ratios reached -1.8%, of which -1.6% was due to the slug flows as against only 0.1% due to phase change. To eliminate the influence of slug flows formed under negative pressure, a novel charging method with a buffer pipeline was proposed. Then a test of five groups of different charging quantities (20 mu L, 25 mu L, 30 mu L, 40 mu L, and 50 mu L) for two MHPs with about 100 mu L internal volume was carried out, and the results suggest that the mean absolute error is below 1 mu L.","Title: An AGV Positioning Algorithm for Reducing the Number of Reflectors\nYear: 2022\n\nAbstract: Aiming at the problem of low global positioning precision and a large number of reflectors in the global feature map, an AGV positioning algorithm for reducing the number of reflectors is proposed. First, the global feature map is constructed by the reflectors. Next, the reflection points are obtained by lidar scanning, in which abnormal reflection points are removed through preprocessing. The local coordinates of the reflector are clustered and fitted by combining the reflection intensity of the reflector point. Then, the global coordinates of the reflectors are obtained by matching the local coordinates of the reflector with the global feature map. Finally, the initial position of the AGV is obtained through the static pose calculation algorithm, and the dynamic position of the AGV is solved by the two-point positioning algorithm. The experimental results show that, compared with the traditional algorithm, the positioning algorithm based on reflectors in this paper decreases the global position precision by 42.0% and 16.1% in the X-axis and Y-axis, respectively, and the number of reflectors used for the positioning algorithm is reduced from three or more to two.","Title: Vegetation Productivity and Precipitation Use Efficiency across the Yellow River Basin: Spatial Patterns and Controls\nYear: 2022\n\nAbstract: In arid and semi-arid climate zones, understanding the spatial patterns and biogeographical mechanisms of net primary production (NPP) and precipitation use efficiency (PUE) is crucial for assessing the function and stability of ecosystem services, as well as directing ecological restoration. Although the vegetation coverage has changed dramatically after the construction of several ecological restoration projects, due to limited observation data, fewer studies have provided a thorough understanding of NPP and PUE's recent spatial patterns and the controlling factors of different vegetation types in the Yellow River Basin (YRB). To narrow this gap, we integrated remote-sensing land-cover maps with long-term MODIS NPP and meteorological datasets to comprehend NPP and PUE spatial patterns in YRB. Furthermore, we applied structural equation models (SEM) to estimate the effect intensity of NPP and PUE controlling factors. The results showed that along geographical coordinates NPP and PUE decreased from southeast to northwest and trends were roughly consistent along latitude, longitude, and elevation gradients with segmented patterns of increasing and decreasing trends. As for climate gradients, NPP showed significant linear positive and negative trends across the mean annual precipitation (MAP) and the arid index (AI), while segmented changes for PUE. However, the mean annual average temperature (MAT) showed a positive slope for below zero temperature and no change above zero temperature for both NPP and PUE. SEM results suggested that AI determined the spatial pattern of NPP, whereas PUE was controlled by MAP and NPP. As the AI becomes higher in the further, vegetation tends to have decreased NPP with higher sensitivity to water availability. While artificial vegetation had a substantially lower NPP than original vegetation but increased water competition between the ecosystem and human society. Hence further optimization of artificial vegetation is needed to satisfy both ecological and economic needs. This study advanced our understanding of spatial patterns and biogeographic mechanisms of NPP and PUE at YRB, therefore giving theoretical guidance for ecological restoration and ecosystem function evaluation in the face of further climate change."],"string":"[\n \"Title: Insar deformation time series analysis using small-baseline approach\\nYear: 2013\\n\\nAbstract: The crustal activities in Dangxiong basin are frequent and a great deal of geothermal energy is converged under the surface. The geothermic resources are used through the exploitation of underground water. Over-extraction of underground fluids causes the subsidence in the geothermal fields. We present the application of small-baseline InSAR time series method to monitor the land surface subsidence and spatial-temporal evolution in Yangbajing. Our data consists of 24 ASAR images acquired from ENVISAT satellite, spanning a time interval from Oct 2006 to Aug 2010. The results show that the maximum surface subsidence rate of the geothermal region is up to 15 mm/yr whilst subsidence rate in other fields is approximately 6 mm/yr.\",\n \"Title: A Scalable and I/O Optimal Skyline Processing Algorithm\\nYear: 2004\\n\\nAbstract: In this paper, we will present a novel progressive algorithm for computing skyline queries. The algorithm is based on the depth-first search paradigm. It can be shown that the new algorithm is I/O optimal. Further, we can show that the algorithm takes a logarithmic memory space in 2D-space in the worst case if there are not many intersections in an adopted R-tree. Our experiment demonstrated that the new algorithm is more scalable and efficient than the existing techniques especially in a low dimensional space. The experiment also showed that the algorithm is progressive in a way sensitive to a user's preference.\",\n \"Title: A New Integration Method of Web-Based Video Monitoring System\\nYear: 2013\\n\\nAbstract: This paper focuses on analysis of a nuclear power group to headquartered brand as the core, to surrounding radiation entire range of video monitoring system of distribution and the management current situation, according to the system's architecture features and user requirements, and based on the use of WPF and Web Service technology, it had proposed and constructed a new integration method and integration framework of unified integration, lightweight video monitoring management platform, to effectively solve the multi-region and multi-brand monitoring system of centralized management, unified authorized. And according to requires, it provide appropriate video service to other application system.\",\n \"Title: Incorporating risk seeking attitude into defense strategy.\\nYear: 2014\\n\\nAbstract: Optimal resource allocation is first found in defending possible targets against random terrorist attacks subject to budget constraint. The mathematical model is a nonconvex optimization problem which can be transformed into a convex problem by introducing new decision variables, so standard methods can be used for its solution. Without budget constraint the simplified model can be solved by a very simple algorithm which requires the solution of a single variable monotone equation.\",\n \"Title: PS-InSAR time series analysis for measuring surface deformation before the L'Aquila earthquake\\nYear: 2010\\n\\nAbstract: L'Aquila area has a high topography and complex geological structures, and is covered with thick vegetation and snow in areas of high topography. To monitor the characteristics of crustal deformation in this region before the 2009 L'Aquila earthquake, we apply StaMPS software to analyse 20 descending ASAR images acquired between September 2003 and March 2007 and 39 ascending ASAR images acquired between February 2003 and March 2009. In this paper, two mean LOS deformation velocity maps are acquired for this area, which reveal the same deformation pattern. Several deformation gradient in this area can be clearly identified, furthermore, we discover that most faults in this region may strike approximately NW-SE and dip <; 90° to SW. We also draw the conclusion that descending SAR images are superior to ascending ones in monitoring crustal deformation with InSAR in this region.\",\n \"Title: FINE: A Fully Informed aNd Efficient Communication-Induced Checkpointing Protocol\\nYear: 2008\\n\\nAbstract: In this paper, first we discuss two critical data structures used in the communication-induced checkpointing (CIC) protocols and their distinct roles in guaranteeing z- cycle free (ZCF) property by tracking the checkpoint and communication pattern (CCPAT) in a distributed computation that can lead to Z-cycles and preventing them. Then, we provide our Transitive Dependency Enabled TimeStamp (TDE_TSS) mechanism by which we can both timestamp each event and get the transitive dependency information upon receiving a message. Finally, based on this times- tamping mechanism, we present our Fully Informed aNd Efficient (FINE) checkpointing algorithm which can not only improve the performance of Fully Informed (FI) CIC protocol proposed by Helary et al. but also decrease the overhead of piggybacked information.\",\n \"Title: Basis set dependence of solute-solvent interaction energy of benzene in water: a HF/DFT study.\\nYear: 2008\\n\\nAbstract: Solute-solvent interaction energies for the benzene molecule dissolved in water are computed using Hartree-Fock and B3LYP density functional theories. Explicit solvent molecules up to 14-angstrom away from the dissolved benzene molecule are included in the calculation of interaction energies. Both basis set dependence and basis Set Superposition errors are carefully examined. It is found that the use of a larger basis set for the region near the solute together with a smaller basis set for the outer region gives results very close to what would have been obtained if the larger basis set had been used for the whole system. It is also shown that a correction for the basis Set superposition error is a necessary component in this kind of calculations. With this correction, results obtained with different tested basis sets converge to within 1 kcal/mol. (c) 2008 Wiley Periodicals, Inc.\",\n \"Title: Children in the forest: towards a canonical problem of spatio-temporal collaboration\\nYear: 2007\\n\\nAbstract: Canonical problems are simplified representations of a class of real world problems. They allow researchers to compare algorithms in a standard setting which captures the most important challenges of the real world problems being modeled. Such examples are the block world for planning, two-player games for algorithms which learn the behavior of the opponent agent, or the \\\"split the pie\\\" game for a large class of negotiation problems. In this paper we focus on negotiating collaboration in space and time, a problem with many important real world applications. Although technically a multi-issue negotiation, we show that the problem can not be represented in a satisfactory manner by the split the pie model. We propose the \\\"children in the rectangular forest\\\" (CRF) model as a possible canonical problem for negotiating spatio-temporal collaboration. By exploring a centralized and a peer-to-peer negotiation based solution, we demonstrate that the problem captures the main challenges of the real world problems while allows us to simplify away some of the computationally demanding but semantically marginal features of real world problems.\",\n \"Title: Semantics Based Conformance Assessment of ebXML Business Processes\\nYear: 2004\\n\\nAbstract: In the business world, the acceptance of a contract often lies beyond the agreement on price and quality of products. The conformance of respective business processes plays a significant role in the collaboration of business partners. Today, e-commerce standards such as ebXML have enabled enterprises to collaborate in the business process level. However, there is little work on the study of conformance assessment (also called matchmaking in some works) of business processes. Moreover, these e-commerce standards are syntactic rather than semantic, in which semantic constraints on interactions are represented informally. In this paper, we extend the ebXML specifications to support the semantics based conformance assessment of business processes, which transforms XML into RDF via the Semantic Web technology. The conformance criteria are mapped to OWL. The semantics based conformance criteria are defined. Furthermore, we extend the ebXML architecture by adding a conformance assessment agent to support the conformance assessment of business processes when searching the potential business partners. With its help, appropriate business partners can be discovered for the client as desired.\",\n \"Title: New acoustic monitoring method using cross-correlation of primary frequency spectrum.\\nYear: 2013\\n\\nAbstract: The acoustic data remotely measured by microphones are widely used to investigate monitoring and diagnose integrity of ball bearing in rotational machines. Early fault diagnosis is very difficult for acoustic emission. We propose a new method using a cross-correlation of frequency spectrum to classify various faults with fine grit. Principal component analysis (PCA) is used to separate the primary frequency spectrum into main frequency and residual frequency. Different with conventional classification using the PCA eigenvalue, we introduce the general cross-correlation (GCC) of main frequency and residual frequency spectrums between a basic signal vector and monitoring signal. Multi-classification strategy based on binary-tree support vector machine (SVM) is applied to perform faults diagnosis. In order to remove noise interference and increase robustness, a normalization method is proposed during time generation. Experiment results show that PCA-GCC-SVM method is able to diagnose various faults with high sensitivity. © 2012 Springer-Verlag.\",\n \"Title: Error Propagation Analysis in Three-Dimensional Coseismic Displacement Inversion\\nYear: 2014\\n\\nAbstract: Using the Bam earthquake as an example, we apply the multiple-aperture interferometry (MAI) algorithm to measure the azimuth (AZI) displacement with multiple mode synthetic aperture radar (SAR) images (ScanSAR and image modes) and further on produce the 3-D coseismic displacement maps using well-known models: multiple independent interferometric SAR (InSAR) with different viewing angles and combining MAI with conventional InSAR. The 3-D displacement maps show that, besides accuracy of SAR observation, inversion model is another major perturbing factor limiting the accuracy of 3-D component reconstruction. That is, in the former model, the smaller the difference of incidence angles is, the more easily influenced by ill-conditioned systems the estimated parameters are. Based on characteristics of error sources of SAR observations, we classify observation errors into random error, systematic error, and gross error. Moreover, their characteristics of error propagation are analyzed in the two models, respectively. Error propagation analysis indicates that random errors only affect variability of inversion result, while systematic error and gross error cause not only variability but also bias or uncertainty in estimated parameters. The presented error analysis method provides a more comprehensive understanding of bias or uncertainty of 3-D estimated components, which will be a useful tool for evaluating errors in displacement fields obtained from SAR observations. In this letter, we also group multiple InSAR and MAI observations to estimate 3-D components using weighted least squares whose weights are given by the Förstner posterior variance estimation, which may avoid an ill-conditioned system, reducing line-of-sight and AZI random noises and improving accuracies of estimated 3-D components.\",\n \"Title: Multi-Level Intrusion Detection System (ML-IDS)\\nYear: 2008\\n\\nAbstract: As the deployment of network-centric systems increases, network attacks are proportionally increasing in intensity as well as complexity. Attack detection techniques can be broadly classified as being signature-based, classification-based, or anomaly-based. In this paper we present a multi level intrusion detection system (ML-IDS) that uses autonomic computing to automate the control and management of ML-IDS. This automation allows ML-IDS to detect network attacks and proactively protect against them. ML-IDS inspects and analyzes network traffic using three levels of granularities (traffic flow, packet header, and payload), and employs an efficient fusion decision algorithm to improve the overall detection rate and minimize the occurrence of false alarms. We have individually evaluated each of our approaches against a wide range of network attacks, and then compared the results of these approaches with the results of the combined decision fusion algorithm.\",\n \"Title: Research on Application and RF EMC of Bidirectional Wireless Communication System in Nuclear Power Plant\\nYear: 2011\\n\\nAbstract: The wireless communication means is necessary for routine work and emergency operating in nuclear power station. With the developments of wireless technical and nuclear power plant, wireless communication system requires more comprehensive and widespread application. The secure and stable bidirectional wireless communication system is to have an important status in plant communication systems. In certain regions of nuclear power plant, such as nuclear island, RF emitting equipments have requirements to their electromagnetic compatibility, which should confirm to certain standards, to guarantee the operation of safety-related systems and the wireless communication system itself.\",\n \"Title: Relation between Boolean operators and Euler operators\\nYear: 1993\\n\\nAbstract: CSG [RET178] and B-rep [BAU72, BR473] are two widely-applied approaches for modelling solids. CSG approach is based on the theory of point set topology, using Boolean operations on primitive “building blocks” to obtain more complicated solid models. However, general Boolean operations based on naive set theory can cause dimension inconsistency and therefore are not closed to pure 3-D objects. To solve the problem, the concepts of regular sets and regularized Boolean operations has been introduced in [RET178] and have been an important contribution to the theory of point set topology, which made the theory being more suitable as the foundation of CSG approach of solid modeling technique.\",\n \"Title: An enhanced model-based checkpointing protocol\\nYear: 2007\\n\\nAbstract: Checkpointing and rollback recovery are widely used techniques to handle failures in distributed computing systems. Usually we avoid taking checkpoints that are useless during the recovery process. Communication-Induced checkpointing algorithms guarantee the usefulness of all the checkpoints and provide considerable autonomy with relatively low overhead. In this paper, we propose an enhanced Communication-Induced checkpointing algorithm. Our algorithm is likely to have less checkpointing overhead than an existing algorithm in the literature.\",\n \"Title: Enhancing CMOS Using Nanoelectronic Devices: A Perspective on Hybrid Integrated Systems.\\nYear: 2010\\n\\nAbstract: In this paper, we present a vision for the cointegration of deeply scaled complementary metal-oxide-semiconductor (CMOS) and emerging nanoelectronic devices into CMOS-hybrid systems. These hybrid systems will create new functionality, modality and add value to existing CMOS integrated circuits. We describe several new nanoelectronic devices which may enable new dimensions to traditional CMOS circu...\",\n \"Title: Analyzing and exploiting the competitiveness of scenarios for negotiating convoy formation under time constraints\\nYear: 2010\\n\\nAbstract: In the convoy formation problem, two embodied agents are negotiating the synchronization of their movement for a portion of the path from their respective sources to destinations. As equilibrium strategies are not practically possible, we are interested in strategies with bounded rationality, which achieve good performance in a wide range of practical negotiation scenarios. Naturally, the performance of a strategy is dependent on the strategy of the opponent and the characteristics of the scenario. The goal of this paper is to develop a collaborativeness metric of the negotiation scenario which formalizes our intuition of collaborative scenarios (where the agents' interests are closely aligned) versus competitive scenarios (where the gain of the utility for one agent is paid off with a loss of utility for the other agent). We are using the Children in the Rectangular Forest (CRF) game as a canonical model of convoy formation, assume zero initial knowledge and a negotiation protocol requiring mandatory, but non-binding evaluations of the opponents offer. We also assume that the negotiation happens in physical time. We describe two negotiation strategies: the comparatively simple Internal Negotiation Deadline (IND) strategy and the computationally more expensive Uniform Concession (UC) strategy. Then, we describe how these strategies can be augmented by collaborativeness analysis: we approximate the collaborativeness metric in the first several negotiation rounds, and use the result to cut short the negotiation when the estimated collaborativeness is lower than a threshold. Through an experimental study, we show that augmenting the strategies with collaborativeness analysis significantly improves their performance for low collaborativeness scenarios, with only a minimal penalty in high collaborativeness scenarios.\",\n \"Title: Quantitative Evaluation of Human-Reliability Based on Fuzzy-Clonal Selection\\nYear: 2011\\n\\nAbstract: Human reliability analysis (HRA) is necessary for system safety assessment as well as equipment reliability analysis. The cognitive reliability and error analysis method (CREAM) as a representative HRA method provides nine common performance conditions (CPCs) to represent the contextual conditions under which a given action is performed. With a scarcity of empirical data, a high uncertainty in analyzing results is produced by subjective judgment. To obtain more objective and effective HRA results, this paper presents an optimized quantification method to evaluate the human error probability (HEP) according to CREAM, and its linguistic variables. The starting point for the quantification is an introduced fuzzy version of CREAM. However, many fuzzy rules are redundant, and occupy extensive computing time. The clonal selection algorithm combined with the fuzzy model is proposed to optimize the rule set. The evaluation method using the fuzzy-clonal selection algorithm is aimed to support possible applications for prospective and retrospective studies in the domain of safety assessment of power systems. The simulations are carried out on four presumed contexts, and a practical power system. The conclusions illuminate the feasibility of the proposed quantitative method.\",\n \"Title: Recommendation of More Interests Based on Collaborative Filtering\\nYear: 2012\\n\\nAbstract: Collaborative Filtering is one of the most important techniques in recommender systems. Current researches on Collaborative Filtering focus on how to improve the accuracy. However, it is of the same importance to recommend more potential interests to users because many of them have more expectations for recommendation list besides the accuracy. Current recommender systems did not address this problem. This paper focuses on how to help users find more interests in the recommendation list. We propose an sampling-based algorithm Probabilistic Top-N Selection to recommend potential interests for users, and propose two metrics, average predicted rating and category coverage, to assess the quality of the recommendation list. Then we conduct a series of experiments on Movie Lens dataset, experimental results demonstrate that our algorithm can significantly improve user experience through providing them with more potential interests.\",\n \"Title: An Optimal Divide-Conquer Algorithm for 2D Skyline Queries\\nYear: 2003\\n\\nAbstract: Skyline query processing is fundamental to many applications including multi-criteria decision making. In this paper, we will present an optimal algorithm for computing skyline in the two dimensional space. The algorithm has the progressive nature and adopts the divide-conquer paradigm. It can be shown that our algorithm achieves the minimum I/O costs, and is more efficient and scalable than the existing techniques. The experiment results demonstrated that our algorithm greatly improves the performance of the existing techniques.\",\n \"Title: Vision-Based Assembly Of Capillary For Microfluidic Device\\nYear: 2006\\n\\nAbstract: The application of plastic microfluidic chips can be extended with quartz capillaries connected at the end of their microchannels, e.g. UV absorption detection method can be carried out, which responds to almost 80% chemical compounds in detection. A vision-based experiment system for automatically assembling capillaries to plastic microfluidic chips was set up. UN-curing adhesive is used for the joining procedure. Visual feedback is implemented in the assembly system and the control algorithm is briefly introduced. The methods for obtaining the spatial position deviation between the capillary and the end of the chip's micro channel are described. The deviation information in x-y plane is obtained by performing image processing and converting pixels into actual distance with calibrated data. Two methods for recovering vertical deviation information were explored, and both are feasible for application, one is the depth-in-focus, the other is with the use of microscopic stereovision.\",\n \"Title: Theoretical and experimental evaluation of communication-induced checkpointing protocols in FE and FLazy-E families\\nYear: 2011\\n\\nAbstract: Communication-induced checkpointing (CIC) protocols help in bounding rollback propagation by ensuring that each checkpoint taken is useful, while at the same time allowing each process to take checkpoints independently. In this paper, we focus on the evaluation of CIC protocols belonging to two families, namely, the F\\\"E family and F\\\"L\\\"a\\\"z\\\"y\\\"-\\\"E family. We present both theoretical and experimental evaluation of the protocols belonging to these two families. The results of our experimental evaluation not only confirm the theoretical comparison but also reveals the fine differences between these protocols.\",\n \"Title: A light-weighted approach to workflow view implementation\\nYear: 2006\\n\\nAbstract: Interaction is the central concern of the B2B E-commerce today. The concept of workflow views provides a convenient interface for advanced business transactions across enterprise boundaries. However, until now there is little work discussing the implementation issue of workflow views. In this paper, we present a light-weighted implementation model for workflow views, which advocates an easy-to-deploy approach to implement workflow view functions based on existing WFMSs without breaking their integrity. Via this approach, enterprises can equip their workflow systems with the versatile workflow views in an efficient and economical way.\",\n \"Title: Cross-axis sensitivity enhancement for a quad beam piezoresistive accelerometer\\nYear: 2013\\n\\nAbstract: MEMS based piezoresistive accelerometers have been used in wide range of industrial applications after decades of development. For future improvement, how to continuously reduce the cross-axis sensitivity to achieve higher main-axis precision is one of the most critical issues. This letter presents a new concept of structure design to deal with cross-axis sensitivity reduction for quad beam piezoresistive accelerometers. By using existed design with combination of new structure component, the spring constant increased and the cross axis sensitivity reduced to 0.22% of the primary axis sensitivity. Instead of using traditional fabrication process, some special designed methods and procedures are proposed to perform the structure shaping and the component combination.\",\n \"Title: Application and improvement discussion about Apriori algorithm of association rules mining in cases mining of influenza treated by contemporary famous old Chinese medicine\\nYear: 2012\\n\\nAbstract: Objective: To investigate and discuss the application and improvement about Apriori algorithm of association rules mining (ARM) in cases mining of influenza treated by contemporary famous old Chinese medicine. Methods: We analyzed the basic principles, processes and algorithms about the Apriori algorithm of ARM, then applied this algorithm to the cases mining of influenza treated by contemporary famous old Chinese medicine. SPSS Clementinel2.0 statistical software was used to mine the association rules between Etiology and traditional Chinese medicine (TCM), Syndromes and TCM, Symptoms and TCM. Then the disadvantage of the algorithm was summarized, and several improved high efficiency algorithms were discussed. Results: The Apriori algorithm of ARM could extract the association rules between common Etiology (Evil of wind, cold, heat and fire) and TCM, Syndromes (Syndromes of wind-heat or wind-cold invading exterior) and TCM, Symptoms (chills, fever, cough, nasal congestion, runny nose) and TCM. However, it became inefficient when the sample was large. Therefore, it was necessary to search for an improved Apriori algorithm in order to enhance the efficiency of ARM of Chinese medicine cases. Conclusion: The classic Apriori algorithm is useful to mine cases of influenza treated by contemporary famous old Chinese medicine, and the improved Apriori algorithm may help to improve the efficiency of mining.\",\n \"Title: Application of data mining technology in excavating prevention and treatment experience of infectious diseases from famous herbalist doctors\\nYear: 2011\\n\\nAbstract: This study is to explore effect and significance of data mining technology (DMT) used in excavating prevention and treatment experience of infectious diseases from famous herbalist doctors (FHDs). DMT methods such as cluster analysis and association rules was applied to the study on FHDs literature on preventing and treating influenza, dysentery, tuberculosis, viral hepatitis and other infectious diseases in order to excavate the inner rules and refine the regular understanding. The result shows that cluster analysis is helpful to summarize the common understanding of experience including concept of syndrome differentiation, regulation of diagnosis and treatment, prescription characteristic, which based on FHDs' prevention and treatment of influenza (including A H1N1), viral hepatitis and other infectious diseases. Association rules greatly contributed to the judgment of relationship between etiology, syndrome, symptoms and herbal prescription of infectious diseases. In conclusion, DMT provides technical support for concise and inheritance of academic thought which originates from FHDs. DMT is of high application value in research of experience of FHDs and relevant literature, and is worth further discussion.\",\n \"Title: The loophole of the improved secure quantum sealed-bid auction with post-confirmation and solution\\nYear: 2013\\n\\nAbstract: In the literature He et al. (Quantum Inf Process, 2011) performed the cryptanalysis about the protocol of secure quantum auction with post-confirmation, and proposed the melioration algorithm in order to defeat the collusion among some malicious bidders in Zhao et al.'s protocol (Zhao et al. in Opt Commun 283:3194, 2010). But unfortunately, this protocol can't defeat the collusion among some malicious bidders either. In this paper, we will analyze the security of He et al.'s protocol and point out the potential loophole. Furthermore, we propose an improved protocol which can defeat the collusion among malicious bidders effectively.\",\n \"Title: An efficient first-principle approach for electronic structures calculations of nanomaterials.\\nYear: 2008\\n\\nAbstract: An efficient parallel implementation has been realized for a recently proposed central insertion scheme (Jiang, Liu, Lu, Luo. J Chem Phys 2006,124,214711; J Chem Phys 2006,125, 149902) that allows to calculate electronic structures of nanomaterials at various density functional theory levels. It has adopted the sparse-matrix format for Fock/Kohn-Sham and overlap matrices, as well as a combination of implicitly restarted Arnoldi methods (IRAM) and spectral transformation for computing selected eigenvalues/eigenvectors. A systematic error analysis and control for the proposed method has been provided based on a strict mathematical basis. The efficiency and applicability of the new implementation have been demonstrated by calculations of electronic structures of two different nanomaterials consisting of one hundred thousand electrons.\",\n \"Title: Accurate bond dissociation enthalpies by using doubly hybrid XYG3 functional.\\nYear: 2011\\n\\nAbstract: In this work, we examine the performance of XYG3, a newly developed doubly hybrid density functional (Zhang, Xu, and Goddard III, Proc Natl Acad Sci USA 2009, 106, 4963), to calculate covalent bond dissociation enthalpy (BDE). We use 5 atoms, 32 molecular radicals, and 116 closed-shell molecules to set up 142 bond dissociation reactions. For the total of 148 heats of formation (HOFs) and 142 BDEs, XYG3 leads to mean absolute deviations (MADs) of 1.45 and 1.87 kcal/mol, respectively. In comparison with some other functionals, MADs for HOFs are 2.31 (M06-2X), 2.98 (B2PLYP-D), 3.04 (BMK), 3.96 (B3LYP), 4.47 (B2PLYP), 5.42 (B2GP-PLYP), 6.46 (PBE0), and 29.93 kcal/mol (B3P86), and the corresponding errors for BDEs are 2.06 (M06-2X), 2.25 (BMK), 2.51 (B2PLYP-D), 2.89 (B2GP-PLYP), 3.30 (B3P86), 3.44 (B2PLYP), 3.87 (PBE0), and 6.14 kcal/mol (B3LYP). (C) 2011 Wiley Periodicals, Inc. J Comput Chem 32: 1824-1838, 2011\",\n \"Title: Human identification using correlation metrics of iris images\\nYear: 2005\\n\\nAbstract: This paper presents work done based on second order statistical features including cross- and auto-correlations as well as co-occurrence matrices of iris images in an attempt to extract a simple, yet powerful, set of features of an iris as a biometric. Prior to our work, the most prevalent methods for iris identification include the frontier work based on the use of quadrature 2-D Gabor wavelets with the Hamming Distance-based classification [1,2], circular Gabor filters with a nearest feature line (NFL) classifier [3], dyadic wavelet transform with the zero-cross detectors [4], texture analysis [9] and transient signal [11], and independent component analysis (ICA) [7], and boundary localization [10]. Our method differs significantly from the earlier approaches to iris recognition in that it relies on the wide-sense stationary approximation to the texture and gray-level characteristics of irises, and aims to lend itself for a single-chip hardware implementation. Our preliminary results show that cross- and auto-correlators along with co-occurrence matrix features are highly likely to be prominent iris discriminators.\",\n \"Title: Performance analysis of ad hoc networks with interference alignment\\nYear: 2012\\n\\nAbstract: The performance of ad hoc networks is fundamentally limited by interference, especially by the interference from nearby transmitting nodes. In this work, we introduce vector space interference alignment (IA) to an ad hoc network scenario to efficiently eliminate interference. However, according to its feasibility conditions, vector space IA is impractical to implement in dense ad hoc networks directly. Therefore, we define an IA range to divide the ad hoc network into smaller local networks. The interference induced by the transmitters located in the pre-specified IA range is completely aligned and eliminated via an IA approach. Considering the effect of the interference from the transmitters located outside the IA range, the upper and lower bounds of outage probability and transmission capacity are characterized. Monte Carlo simulation results have validated the performance improvement provided by the proposed IA scheme in ad hoc networks.\",\n \"Title: Reversible image water marking based on prediction-error expansion and compensation\\nYear: 2011\\n\\nAbstract: Prediction-error expansion (PEE) develops Tian's difference expansion technique by performing reversible data embedding in the prediction-error histogram. As the prediction accuracy greatly affects the embedding performance, the PEE-based algorithms depend heavily on image's spatial redundancy. However, one drawback of these algorithms is that the modification of pixels may distort the high correlation in their local regions, and thus affect the prediction accuracy. To deal with this problem, we propose an adjustment process named \\\"compensation\\\" to compensate for the already modified pixels, before using them for prediction. Combining PEE and compensation together, a new reversible image watermarking algorithm is then presented. Comparisons with state-of-the-art works indicate that the compensation technique may benefit reversible watermarking in term of capacity-distortion behavior.\",\n \"Title: Integration of multiple heterogeneous databases in Smalltalk\\nYear: 2005\\n\\nAbstract: Providing integrated access to multiple, distributed, heterogeneous databases has become very important. Smalltalk can be used to achieve such an objectivity since Smalltalk can provide tools to connect commercial databases like Oracle and Sybase. We also developed tools to connect open source databases like Post-greSQL. Using these tools, data from multiple heterogenous databases can be extracted and mapped into objects in Smalltalk, where their syntactical and semantical conflicts can be resolved by object deputy model. An object deputy language is designed based on object deputy algebra and its compiler has been implemented in Smalltalk. In order to facilitate the use of object deputy language for data integration, we implemented an object deputy browser in Smalltalk.\",\n \"Title: TCM syndromes diagnostic model of hypertension: Study based on Tree Augmented Naive Bayes\\nYear: 2011\\n\\nAbstract: To establish a Bayesian diagnosis model of TCM symptoms by using the hypertension epidemiological Syndrome databases. The Clementine 12.0 software is used to build the Tree Augmented Naive Bayes models, calculate the Bayesian conditional probability, and compare the forecast accuracy of the syndrome diagnosis model. The training sample had 384 cases and calculated 69 symptoms and signs, without prior knowledge, the prediction accuracy rate of the training model are 72.11%, and with the prior knowledge, the testing sample had 384 cases, the prediction accuracy rate of testing model is up to 78.55%. Through the sample study, Bayesian networks can improve the prediction accuracy; we can build a more accurate hypertension diagnosis model through the current work.\",\n \"Title: SPARK: A Keyword Search Engine on Relational Databases\\nYear: 2008\\n\\nAbstract: Relational database is the most widely adopted and mature technology for information storage. As many services on the Web (e.g., blog and wiki sites) and advanced applications (e.g., customer relationship management systems and content management systems) are built on RDBMSs, increasing amount of text data is now stored in relational databases, accompanied by increasing demands of retrieving relevant information by free-style keyword search.\",\n \"Title: Improved DE-based reversible watermarking using sorting and histogram shifting\\nYear: 2010\\n\\nAbstract: In this paper, we present a revised reversible watermarking scheme based on the following techniques: difference expansion, sorting, and histogram shifting. The scheme emphasizes on low distortion with appointed capacity. Experimental results show that this novel algorithm keeps high PSNR with required payload, and its performance is better than some state-of-the-art algorithms.\",\n \"Title: Deputy mechanism for workflow views\\nYear: 2005\\n\\nAbstract: Adapted from the concept of views in databases, workflow views are derived from workflows as a fundamental support for workflow inter-operability and visibility by external parties in a e-service environment. However, until now there are few works focusing on its realization mechanism, i.e. the communication between views and their source entities. In this paper, we extend the object deputy model to the workflow deputy model supporting the interaction of workflow views in a systematic way. In this workflow deputy model, we formally specify the deputy class and the deputy algebra for workflow classes. According to the process meta-model of XPDL, deputy operations are defined for each kind of workflow component class specifically. Based on this deputy mechanism, workflow views are presented in forms of deputy classes. Lastly, several modeling issues are discussed.\",\n \"Title: A model for evaluating QoE of mobile Internet services\\nYear: 2012\\n\\nAbstract: In recent years, with the increasingly intense competition in mobile Internet services, both network operators and application developers pay more and more attention to Quality of Experience (QoE). However, there is no universal QoE evaluation model and method for mobile Internet services. In this paper, we propose a universal QoE model and evaluation method for mobile Internet services from a mobile application perspective. The QoE value obtained through our model is the overall subjective feelings of end-users for a mobile application in specific network, instead of simple “Excellent” or “Good”.\",\n \"Title: Achieving Subpixel Georeferencing Accuracy in the Canadian AVHRR Processing System\\nYear: 2010\\n\\nAbstract: Precise geolocation is one of the fundamental requirements for satellite imagery to be suitable for climate applications. The Global Climate Observing System and the Committee on Earth Observing Satellites identified the requirement for the accuracy of geolocation of satellite data for climate applications as 1/3 field of view (FOV). This requirement for the series of the Advanced Very High Resolu...\",\n \"Title: Context-aware HCI service selection\\nYear: 2012\\n\\nAbstract: Context-awareness has become a key issue in Human-Computer InteractionHCI to provide better user experience under multi-device and multi-modal environment. With this intuition, we have proposed a web service based framework, which associates interactions with services, and provided service selection mechanism using context knowledge to achieve smart interaction migration [1]. A fundamental problem of such a service-oriented framework for interaction migration is to design an effective while scalable algorithm for service selection. In this paper, we propose a service selection algorithm considering not only context information and user preferences but also inter-service relations such as relative location. Our algorithm detects interaction hot spots within user active scope and presents the best service combination based on evaluation of interaction effectiveness. We also conduct simulation and the results illustrate that our algorithm is effective and scalable for interaction service selection.\",\n \"Title: FINE: A Fully Informed aNd Efficient communication-induced checkpointing protocol for distributed systems\\nYear: 2009\\n\\nAbstract: Communication-Induced Checkpointing (CIC) protocols are classified into two categories in the literature: Index-based and Model-based. In this paper, we discuss two data structures being used in these two kinds of CIC protocols, and their different roles in helping the checkpointing algorithms to enforce Z-cycle Free (ZCF) property. Then, we present our Fully Informed aNd Efficient (FINE) communication-induced checkpointing algorithm, which not only has less checkpointing overhead than the well-known Fully Informed (FI) CIC protocol proposed by Helary et al. but also has less message overhead. Performance evaluation indicates that our protocol performs better than many of the other existing CIC protocols.\",\n \"Title: Precoding design using interference alignment for the network MIMO\\nYear: 2009\\n\\nAbstract: In this paper, an interference alignment system for the MIMO network is investigated. Three different precoding schemes, which are based on zero-forcing (ZF), minimum mean square error (MMSE) and maximum SLR criteria, are proposed. The simulation results show that the proposed precoding schemes are very efficient and can provide good performance for the considered MIMO network.\",\n \"Title: A boundary representation for form features and non-manifold solid objects\\nYear: 1991\\n\\nAbstract: A boundary scheme derived from the con- cept of cell decomposition is presented for modelling form features. \\\"Wedges\\\" and \\\"bundles\\\" are added to the data structure for handling non-manifold edges and vertices in the same way as handling multiply connected faces with loops. With a feature-based and ajoint-based llttler-Poincar6 formulae, feature operators and joint op- erators are determined for manipulating the data struc- ture which can explicitly represent both features and the joints between them and, at the same time, keep the topological adjacency relationships of the complete solid boundary. The properties of Euler operators are also discussed.\",\n \"Title: HOPE: A Hybrid Optimistic checkpointing and selective Pessimistic mEssage logging protocol for large scale distributed systems\\nYear: 2012\\n\\nAbstract: Future generation supercomputers will be message-passing distributed systems consisting of hundreds of thousands of processors. As the size of the system grows, failure rate increases. Hence for the success and deployability of such large scale systems, scalable checkpointing and recovery protocols need to be implemented. Existing checkpointing and rollback recovery protocols used for providing fault tolerance in distributed systems are not scalable to such large systems. In this paper, we address this important and timely issue and propose a scalable group-based Hybrid Optimistic checkpointing and selective Pessimistic mEssage logging (HOPE) protocol. Performance evaluation indicates, our protocol takes a balanced approach to lower checkpointing and message logging overhead and enhances scalability.\",\n \"Title: Linear Decision Fusion Under The Control Of Constrained Pso For Wsns\\nYear: 2012\\n\\nAbstract: A major application of a distributed WSN (wireless sensor network) is to monitor a specific area for detecting some events such as disasters and enemies. In order to achieve this objective, each sensor in the network is required to collect local observations which are probably corrupted by noise, make a local decision regarding the presence or absence of an event, and then send its local decision to a fusion center. After that, the fusion center makes the final decision depending on these local decisions and a decision fusion rule, so an efficient decision fusion rule is extremely critical. It is obvious that the decision-making capability of each node is different owing to the dissimilar signal noise ratios and some other factors, so it is easy to understand that a specific sensor contribution to the global decision should be constrained by this sensor decision-making capability, and, based on this idea, we establish a novel linear decision fusion model for WSNs. Moreover, the constrained particle swarm optimization (constrained PSO) algorithm is creatively employed to control the parameters of this model in this paper and we also apply the typical penalty function to solve the constrained PSO problem. The emulation results indicate that our design is capable of achieving very high accuracy.\",\n \"Title: Locating steganographic payload for LSB matching embedding\\nYear: 2011\\n\\nAbstract: Many highly sensitive detectors for least significant bit (LSB) matching steganography have been proposed so far, but few of them can locate the embedding payload. Assuming a number of stego images with payload placed in the same locations are provided, Ker presented a residual-based method to identify the payload-carrying locations for LSB matching. In this paper, we put forward two novel residuals and theoretically prove their reliability for LSB matching detection. Experimental results show that the proposed weighted l1 and l2 residuals significantly outperform the previous work in terms of both detection performance and computational complexity. Even very small payload can be perfectly detected and precisely located as long as adequate stego images are available.\",\n \"Title: An improved co-evolution genetic algorithm for combinatorial optimization problems\\nYear: 2011\\n\\nAbstract: This paper presents an improved co-evolution genetic algorithm (ICGA), which uses the methodology of game theory to solve the mode deception and premature convergence problem. In ICGA, groups become different players in the game. Mutation operator is designed to simulate the situation in the evolutionary stable strategy. Information transfer mode is added to ICGA to provide greater decision-making space. ICGA is used to solve large-scale deceptive problems and an optimal control problem. Results of numerical tests validate the algorithm's excellent performance.\",\n \"Title: SPARK2: Top-k Keyword Query in Relational Databases\\nYear: 2011\\n\\nAbstract: With the increasing amount of text data stored in relational databases, there is a demand for RDBMS to support keyword queries over text data. As a search result is often assembled from multiple relational tables, traditional IR-style ranking and query evaluation methods cannot be applied directly. In this paper, we study the effectiveness and the efficiency issues of answering top-k keyword query in relational database systems. We propose a new ranking formula by adapting existing IR techniques based on a natural notion of virtual document. We also propose several efficient query processing methods for the new ranking method. We have conducted extensive experiments on large-scale real databases using two popular RDBMSs. The experimental results demonstrate significant improvement to the alternative approaches in terms of retrieval effectiveness and efficiency.\",\n \"Title: SPARK2: Top-k Keyword Query in Relational Databases\\nYear: 2007\\n\\nAbstract: With the increasing amount of text data stored in relational databases, there is a demand for RDBMS to support keyword queries over text data. As a search result is often assembled from multiple relational tables, traditional IR-style ranking and query evaluation methods cannot be applied directly. In this paper, we study the effectiveness and the efficiency issues of answering top-k keyword query in relational database systems. We propose a new ranking formula by adapting existing IR techniques based on a natural notion of virtual document. We also propose several efficient query processing methods for the new ranking method. We have conducted extensive experiments on large-scale real databases using two popular RDBMSs. The experimental results demonstrate significant improvement to the alternative approaches in terms of retrieval effectiveness and efficiency.\",\n \"Title: Robot control with a fully tuned Growing Radial Basis Function neural network\\nYear: 2011\\n\\nAbstract: A fully tuned Growing Radial Basis Function (GRBF) neural network controller for the control of robot manipulators is proposed. In addition to the weights, the centers and the standard variations are adapted online. Furthermore, we present an algorithm in which nodes of the network are appended based on sliding window performance criteria. Lyapunov analysis is used to show uniform ultimate boundedness and a discretization method is used to derive the growing algorithm. Simulations of a 2-DOF planar robot arm are presented to illustrate the method.\",\n \"Title: Improving Performance Using Interference Alignment on Modulation Signal for MIMO System\\nYear: 2010\\n\\nAbstract: In this paper, an interference alignment system for the distributed MIMO network is investigated. We propose a new precoding scheme using interference alignment in modulation signal domain. The simulation results show that the proposed one-dimensional precoding scheme can provide significant performance improvement over the conventional schemes using interference alignment.\",\n \"Title: Phrase-based statistical machine translation by using reordering search and additional features\\nYear: 2006\\n\\nAbstract: The state of the art statistical machine translation (SMT) systems are based on phrase (a group of words), which are modeled using log-linear maximum entropy framework. In this paper, we constructed a phrase-based statistical machine translation system with additional feature models. The translation model is combined with four specific additional feature functions. When comparing our system with the baseline system of IWSLT2005, we can conclude that our system improve the SMT system accuracy with the same corpus.\",\n \"Title: Object-Oriented Realization of Workflow Views for Web Services - An Object Deputy Model Based Approach\\nYear: 2004\\n\\nAbstract: Adapted from the concept of views in databases, workflow views are derived form workflows as a fundamental support for workflow inter-operability and visibility by external parties in a web services environment. However, because of the implementation difficulties of views in OODB systems, it is tough to realize workflow views in objected-oriented workflow management systems (00 WFMS). In this paper, we adopt the object deputy model to support the realization of workflow views in 00 WFMS. The detailed definitions are given based on a reference model of an 00 WFMS, namely ADOME-WFMS. Furthermore, we introduce E-ADOME, which enables the implementation of workflow views in the web services environment.\",\n \"Title: Iterative Minimum Mean Square Error Interference Alignment Scheme For The Mimo X Channel\\nYear: 2011\\n\\nAbstract: In this paper, we propose a new interference alignment (IA) scheme that jointly designs the linear transmitter and receiver for the 2-user MIMO X channel system, using minimum total mean square error criterion, subject to each transmitter power constraint. We show that transmitters and receivers under such criteria could be realized through a joint iterative algorithm. Considering the imperfection of channel state information (CSI), we also extend the minimum mean square error interference alignment schemes for the MIMO X channel with CSI estimation error. A robust iterative algorithm which is insensitve to CSI estimation error is proposed. Simulation results are also provided to demonstrate the proposed algorithm.\",\n \"Title: Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs\\nYear: 2008\\n\\nAbstract: Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake - it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and time-consuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RRER Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SPR, and the simulation results confirm the effectiveness of the SRR approach.\",\n \"Title: An optimistic checkpointing and message logging approach for consistent global checkpoint collection in distributed systems\\nYear: 2008\\n\\nAbstract: Checkpointing and rollback recovery are widely used techniques for achieving fault-tolerance in distributed systems. In this paper, we present a novel checkpointing algorithm which has the following desirable features: A process can independently initiate consistent global checkpointing by saving its current state, called a tentative checkpoint. Other processes come to know about a consistent global checkpoint initiation through information piggy-backed with the application messages or limited control messages if necessary. When a process comes to know about a new consistent global checkpoint initiation, it takes a tentative checkpoint after processing the message (not before processing the message as in existing communication-induced checkpointing algorithms). After a process takes a tentative checkpoint, it starts logging the messages sent and received in memory. When a process comes to know that every other process has taken a tentative checkpoint corresponding to current consistent global checkpoint initiation, it flushes the tentative checkpoint and the message log to the stable storage. The tentative checkpoints together with the message logs stored in the stable storage form a consistent global checkpoint. Two or more processes can concurrently initiate consistent global checkpointing by taking a new tentative checkpoint; in that case, the tentative checkpoints taken by all these processes will be part of the same consistent global checkpoint. The sequence numbers assigned to checkpoints by a process increase monotonically. Checkpoints with the same sequence number form a consistent global checkpoint. We also present the performance evaluation of our algorithm.\",\n \"Title: An Error Correction Method for Binary and Multiple-Valued Logic\\nYear: 2011\\n\\nAbstract: This paper presents a method and circuit for correcting faults in logic systems. The method, called \\\"restorative feedback\\\" (RFB), is similar in some respects to triple modular redundancy (TMR), but has an improved error probability with respect to transient errors. Simulation results indicate an improvement by about two orders of magnitude compared to traditional TMR. CMOS circuits are presented for implementing restorative feedback. For binary logic, a dynamic CMOS circuit is considered. For multiple-valued logic, a semi-floating gate implementation is presented.\",\n \"Title: Adaptive pressure ultrasonic precise bonding method for polymer micro joint\\nYear: 2010\\n\\nAbstract: Ultrasonic precise bonding for polymer micro joint was studied. Considering shape deviation as the key issue to successful micro bonding, an ultrasonic bonding system was established, which employed 60 kHz ultrasonic transducer that achieved bonding at low amplitude. Adaptive ultrasonic bonding with bonding energy auto-selected was proposed. In this method, continues decreasing pressure was imposed on the micro components, the heat was accumulated and when the interface reached the melting point of the polymer, the pressure skip detected by the sensor and treated as the signal to turn off the ultrasonic vibration by the system. Polymer mechanical behavior was the control parameter in this method, precise energy for each component was auto-selected by system, and this solved the problem of surface roughness deviation form micro component and made small deformation of microstructure. Based on this method, linear guide was chosen to drive the ultrasonic horn. A kind of micro pump seat was bonded by this system. The joint had a transparent bonding interface and shear strength of 8 MPa which met the demand of MEMS. The interfacial temperature was measured during bonding. The influence of bonding pressure to the bonding quality was obtained. The result is contributed to ultrasonic bonding process optimizing and system design.\",\n \"Title: Fast binary partition tree based variable-size block-matching for video coding\\nYear: 2009\\n\\nAbstract: In this work, we develop a fast binary partition tree based variable size video coding system. New adaptive algorithms proposed herein are applied to a video encoder with binary partition trees. First, to reduce the computation for block-matching, an adaptive search area method is described which adjusts the searching region according to the size of each block. Second, an early termination method is introduced which terminates the binary partitioning process adaptively according to the statistics of the peak-signal-to-noise-ratio values during each step of block splitting. Third, we put forward a new model for fast rate-distortion (RD) estimation to decrease the computation of matching pursuit (MP) transform coding. Simulation results show that the proposed techniques provide significant gain in computation speed with little or no sacrifice of RD performance, when compared with non-adaptive binary partitioning scheme.\",\n \"Title: How independent are the appearances of n-mers in different genomes?\\nYear: 2004\\n\\nAbstract: Analysis of statistical properties of DNA sequences is important for evolutional biology as well as for DNA probe and PCR technologies. These technologies, in turn, can be used for organism identification, which implies applications in the diagnosis of infectious diseases, environmental studies, etc.We present results of the correlation analysis of distributions of the presence/absence of short nucleotide subsequences of different length ('n-mers', n = 5-20) in more than 1500 microbial and virus genomes, together with five genomes of multicellular organisms (including human). We calculate whether a given n-mer is present or absent (frequency of presence) in a given genome, which is not the usually calculated number of appearances of n-mers in one or more genomes (frequency of appearance). For organisms that are not close relatives of each other, the presence/absence of different 7-20mers in their genomes are not correlated. For close biological relatives, some correlation of the presence of n-mers in this range appears, but is not as strong as expected. Suppressed correlations among the n-mers present in different genomes leads to the possibility of using random sets of n-mers (with appropriately chosen n) to discriminate genomes of different organisms and possibly individual genomes of the same species including human with a low probability of error.\",\n \"Title: A Stern-based Collusion-Secure Software Watermarking Algorithm and Its Implementation\\nYear: 2007\\n\\nAbstract: Stern algorithm is a robust static software watermarking scheme. It can resist many common attacks except collusive attacks. In this paper we propose an improved Stern algorithm, make it has the ability of resisting collusive attacks and simplify its implementation at the same time. Furthermore, we describe the implementation of our algorithm and the issues that arise when targeting MSIL. We then validated it by experiments against a variety of attacks.\",\n \"Title: On the performance of asynchronous ad-hoc networks using interference alignment with renewal process\\nYear: 2013\\n\\nAbstract: The performance of ad-hoc networks is greatly affected by interference, particularly interference from nearby nodes. Based on stochastic geometry, this work studies a form of multiple-input-multiple-output (interference alignment (IA) that eliminates interference from transmitters within a range and treats the remaining interference as a shot noise process. Adapting to the bursty nature of ad-hoc network traffic, the authors introduce a novel distributed ad-hoc network with renewal process, whereby cooperation between interferer and receiver is implemented in one-way process, which results from the difficulties for the node to change the beamforming or receiving matrix whereas communicating with a proposed transmitter. In addition, this scheme takes advantage of IA, leaving the desired signal with higher degree of freedom (DoF) compared with the partially zero-forcing method. Outage probability and transmission capacity are derived with and without Rayleigh fading. Simulation results show the effect of IA in ad-hoc network, including the incremental in the DoF of the desired signal as time goes by. Monte Carlo simulations are implemented and show that IA outperforms successive interference cancellation by at least 10 dB in terms of the signal-to-interference ratio with large path-loss exponent.\",\n \"Title: The New Interference Alignment Scheme for the MIMO Interference Channel\\nYear: 2010\\n\\nAbstract: In this paper, we propose a new interference alignment (IA) scheme designing jointly the linear transmitter and receiver for the MIMO interference channel system, using minimum total mean square error criterion, subject to individual transmit power constraints. We show that transmitter and receiver under such criterion could be realized through a joint iterative algorithm. The convergence of the proposed algorithm is discussed. We also proposed a robust MMSE-based iterative design with imperfect channel state information (CSI). The proposed robust MMSE-based iterative interference alignment scheme is shown to be less sensitive to channel estimation errors. Simulation results show that the proposed schemes outperform the existing IA schemes with fast convergence.\",\n \"Title: Learning Models of the Negotiation Partner in Spatio-temporal Collaboration\\nYear: 2008\\n\\nAbstract: We describe an approach for learning the model of the opponent in spatio-temporal negotiation. We use the Children in the Rectangular Forest canonical problem as an example. The opponent model is represented by the physical characteristics of the agents: the current location and the destination. We assume that the agents do not disclose any of their information voluntarily; the learning needs to rely on the study of the offers exchanged during normal negotiation. Our approach is Bayesian learning, with the main contribution being four techniques through which the posterior probabilities are determined. The calculations rely on (a) feasibility of offers, (b) rationality of offers, (c) the assumption of decreasing utility, and (d) the assumption of accepting offer which is better than the next counter-offer.\",\n \"Title: Performance of homogeneous and asynchronous ad hoc network with interference alignment\\nYear: 2013\\n\\nAbstract: In this work, we introduce multiple-input-multiple-output (MIMO) interference alignment (IA) in an homogeneous and asynchronous ad hoc network. Perfect channel state information and working status of nodes are conveyed by instantaneous feedback link to one-hop neighbors. Transmitters align their interference to receivers and receivers eliminate interference by zero-forcing method asynchronously. The feasibility conditions for IA are considered as a critical factor to the performance, and the situations are divided according to whether the feasibility condition can be satisfied or not. We derive closed-form expressions for the upper and lower bounds on outage probability and transmission capacity in both cases. Numerical results show that with larger path loss exponent and number of antennas, the performance increases because a greater proportion of the interference can be eliminated.\",\n \"Title: A game theory based risk and impact analysis method for Intrusion Defense Systems\\nYear: 2009\\n\\nAbstract: An enormous amount of functions in our everyday life became dependent on computer networks. Network attacks become more sophisticated and perplexing. Defending against multi-stage attacks is a challenging process in intrusion defense systems (IDS) due to their complexity. This paper presents a game theory method to analyze the risk and impact of multi-stage attacks in IDS. In this method, the interactions between the attacker and the administrator are modeled as a non-cooperative zero-sum multistage game and it is modeled as a minmax game tree where the attacker is the leader and the administrator is the follower. Alternating the actions between the administrator and the attacker forms the game tree, each of them will be allowed to play a single action at any given time. In this work, a new multi-stage attacker defender (MAD) algorithm is developed to help the administrator in defending against multi-stage attacks. The believes of the attacker and the administrator are updated based on the analysis of the life-cycle for the multi-stage attacks to reduce the horizon effect.\",\n \"Title: Similarity search with implicit object features\\nYear: 2005\\n\\nAbstract: Driven by many real applications, in this paper we study the problem of similarity search with implicit object features; that is, the features of each object are not pre-computed/evaluated. As the existing similarity search techniques are not applicable, a novel and efficient algorithm is developed in this paper to approach the problem. The R-tree based algorithm consists of two steps: feature evaluation and similarity search. Our performance evaluation demonstrates that the algorithm is very efficient for large spatial datasets.\",\n \"Title: Study of polymeric MEMS micro-pump actuated by PZT bimorph\\nYear: 2013\\n\\nAbstract: Check valve micro-pump is easy to reach high flow rate and has a promising application prospect in micro fluidic devices and artificial organs. There are several vibration elements in check valve pump, including actuator, membrane and valves. The vibration performances of these elements have a coupling influence on the performance of micro-pump. In this paper, the comprehensive analysis was carried out using finite element model. Four kinds of micro-pumps with different valves and actuators were designed and fabricated. The performances of each kind of micro-pumps are studied by frequency sweeping experiments. Experimental results approximately coincide with the theoretical analysis. This research provides a theoretical and experimental basis for subsequent micro-pump design.\",\n \"Title: A radiosonde using a humidity sensor array with a platinum resistance heater and multi-sensor data fusion.\\nYear: 2013\\n\\nAbstract: This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes.\",\n \"Title: Novel back-to-back uni-traveling-carrier photodiodes with high responsivity and wide bandwidth\\nYear: 2013\\n\\nAbstract: Novel back-to-back uni-traveling-carrier photodiodes are proposed and demonstrated. High responsivity of 0.83 A/W and wide bandwidth over 40 GHz are realized simultaneously in mesa-structure photodiodes for the first time. © 2013 OSA.\",\n \"Title: Cooperative Wideband Spectrum Detection Based on Maximum Likelihood Ratio for CR Enhanced VANET.\\nYear: 2013\\n\\nAbstract: Cognitive radio (CR) enhanced vehicular ad hoc network (CR-VANET) is a special VANET that each vehicle could explore local spectrum gap and reduce data congestion by mitigating interference by dynamically accessing spectrum holes. One of the most important challenges for CR-VANET is to identify the presence of primary users (PU) over wideband spectrum at a particular time and specific geographic location. In this paper, maximum likelihood ratio (MLR) detection is proposed as an effective scheme for wideband spectrum detection in orthogonal frequency division multiplexing (OFDM) based overlay CR-VANET. OR fusion rule with square-law selection (SLS) is implemented at roadside to make global detection decision by means of the combination of each vehicle's local sensing results. Hence, cooperative wideband spectrum detection is implemented in dynamic topology CR-VANET to enhance the reliability of spectrum detection. Specifically, robust cooperative sensing technique is investigated with the consideration of sensing channel SNR, reporting channel fading, as well as inter-user error rate, with the purpose of exploiting diversity in multi-vehicle cooperative sensing scenario. Limitations of cooperative wideband spectrum sensing are presented with MLR detection in space-time block code (STBC) and time division multiple access (TDMA) protocols for practical consideration. Simulation results are presented to confirm our theoretical derivations. It is revealed that, compared with conventional energy detection (ED), cooperative wideband spectrum detection with MLR has adaptive detection thresholds. Moreover, robust cooperative sensing by roadside SLS OR rule and its limitations are also performed with receiver operation characteristics (ROC). It is proven that, MLR detection is available in robust cooperative sensing with dynamic threshold variations for CR-VANET practical applications. © 2013 Engineering and Technology Publishing.\",\n \"Title: Evaluation of non-water-stressed baselines for crop water stress monitoring in North China Plain\\nYear: 2002\\n\\nAbstract: Canopy surface temperature measured with infrared thermometers or other remote IR sensor is an important tool for crop water stress monitoring. Crop Water Stress Index (CWSI) is the most often used index to detect crop water stress based on canopy surface temperature. The calculation of CWSI relies on two baselines: the non-water-stressed baseline, and the maximum stressed baseline. This paper evaluates the application of the most often used non-water-stressed baselines in North China Plain (NCP): the Idso's empirical baseline, and the Jackson's theoretical baseline. The results show that the Jackson's model makes better than the Idso's in monitoring winter wheat water stress in NCP.\",\n \"Title: Error Correction via Restorative Feedback in M-ary Logic Circuits.\\nYear: 2014\\n\\nAbstract: This paper presents an error correction method known as restorative feedback (RFB) that provides error-correction for both permanent and temporal logic faults in any M-ary logic system. The RFB method is a variant of triple modular redundancy (TMR), which achieves error correction in logic circuits by using three-fold redundancy. Unlike TMR, the RFB method has well-defined application to arbitrary M-ary logic systems as well as conventional binary logic circuits. The RFB method also uses a feedback mechanism to suppress transient errors, resulting in a lower error probability than TMR when considering transient upsets. The underlying theory of RFB is presented as an adaptation of stochastic error correction theory. Two circuit-level proof-of-concept demonstrations are presented, which include a binary implementation using Muller C-elements, and a ternary implementation based on Semi-Floating Gate logic circuits. The error-correcting performance of these circuits is evaluated using logic-level simulations as well as devicelevel simulations in Spectre. Bit and symbol error rates are also computed using Monte Carlo simulations which demonstrate that the RFB method is superior to traditional TMR for a variety of cases. An application of the RFB method is also demonstrated using redundant gate-level synthesis of multiple-valued ripple-carry adder circuits. The application circuits are simulated using an abstract noisy-logic model, and the RFB method is shown to significantly improve the circuits' noise immunity.\",\n \"Title: Degrees-of-Freedom Regions for $K$-User MISO Time-Correlated Broadcast Channel.\\nYear: 2014\\n\\nAbstract: In this paper, we study the achievable degrees-of-freedom (DoF) regions of the $K$-user multiple-input-single-output (MISO) time correlated broadcast channel (BC). The time correlation induces knowledge of the current channel state information at transmitter (CSIT) with an estimation error $P^{-\\\\alpha}$, where $P$ is the signal-to-noise ratio (SNR). We consider the following two scenarios: $(i)$ $K$-user with $K$-antenna base station (BS) and $(ii)$ $3$-user with $2$-antenna BS. In case of symmetric DoF tuples, where all the users obtain the same DoF, we derive the total DoF equal to $\\\\frac{K(1-\\\\alpha)}{1+\\\\frac{1}{2}+\\\\cdots+\\\\frac{1}{K}}+K\\\\alpha$ for the first scenario and $\\\\frac{3+\\\\alpha}{2}$ for the second one. In particular, we provide the achievability schemes for these two DoF tuples. Nevertheless, we also consider the asymmetric case where one of the users is guaranteed {\\\\it one} DoF, and provide the achievability scheme. Notably, the consistency of the proposed DoF regions with an already published outer bound , as well as with the Maddah-Ali-Tse (MAT), which assumes only perfect delayed CSIT, and the ZF beamforming schemes (perfect current CSIT) consents to the optimality of the proposed achievability schemes.\",\n \"Title: Linked vaccine adverse event data from VAERS for biomedical data analysis and longitudinal studies.\\nYear: 2014\\n\\nAbstract: Vaccines have been one of the most successful public health interventions to date. The use of vaccination, however, sometimes comes with possible adverse events. The U.S. FDA/CDC Vaccine Adverse Event Reporting System (VAERS) currently contains more than 200,000 reports for post-vaccination events that occur after the administration of vaccines licensed in the United States. Although the data from the VAERS has been applied to many public health and vaccine safety studies, each individual report does not necessarily indicate a casuality relationship between the vaccine and the reported symptoms. Further statistical analysis and summarization needs to be done before this data can be leveraged.This paper introduces our efforts on representing the vaccine-symptom correlations and their corresponding meta-information extracted from the VAERS database using Resource Description Framework (RDF). Numbers of occurrences of vaccine-symptom pairs reported to the VAERS were summarized with corresponding proportional reporting ratios (PRR) calculated. All the data was stored in an RDF file. We then applied network analysis approaches to the RDF data to illustrate a use case of the data for longititual studies. We further dicussed our vision on integrating the data with vaccine information from other sources using RDF linked approach to facilitate more comprehensive analyses.The 1990-2013 data from VAERS has been extracted from the VAERS database. There are 83,148 unique vaccine-symptom pairs with 75 vaccine types and 5,865 different reported symptoms. The yearly and over PRR values for each reported vaccine-symptom pair were calculated. The network properties of networks consisting of significant vaccine-symptom associations (i.e., PRR larger than 1) were then investigated. The results indicated that vaccine-symptom association network is a dense network, with any given node connected to all other nodes through an average of approximately two other nodes and a maximum of five nodes.\",\n \"Title: Degrees of freedom region of MIMO interference channel with imperfect current and delayed CSIT\\nYear: 2014\\n\\nAbstract: In this paper, we study the degrees of freedom (DoF) of the two-user time-correlated multiple-input-multiple-output (MIMO) interference channel (IC), under realistic assumptions. In particular, the transmitters have imperfect knowledge of the current and the delayed channel state information (CSI). The novelty of this study relies upon the fact that this is the first time, within the literature of IC, that imperfect CSI is addressed for such a case. The delayed CSI at the transmitter (CSIT) is assumed to be more accurate than the current value. We identify the DoF region, which provides an insight on the behaviour of the DoF as a function of the varying qualities of the current and the delayed channel. It is also worth mentioning that any knowledge of imperfect delayed CSIT can also be utilized. Furthermore, an achievability scheme is proposed for each vertex in DoF region. Finally, simulation of the proposed scheme verifies our results.\",\n \"Title: Managing Large Scale Unstructured Data with RDBMS\\nYear: 2013\\n\\nAbstract: With the rapid development of information technology, the needs of unstructured data storage and processing is growing rapidly, which develops a new requirement for the database storage. Traditional row-oriented relational databases appear to be inadequate for the data query and analysis. In this paper, we propose a novel approach to store the unstructured data in a relational database. By splitting the VALUE property of the unstructured KEY/VALUE data and recreating the two-dimensional data, the original data can be stored in relational databases. The system introduced in this paper is designed to handle this task. In addition, this system rebuilds the SQL as its query language, which makes it compatible with relational databases. In experiments of the query for unstructured data, the outcomes show that the system is good at decomposing the SQL statement submitted by users, and generating the corrected sub-query statements. The results of the experiments show that the performance of this system is good.\",\n \"Title: An Empirical Algorithm for Bias Correction Based on GC Estimation for Single Cell Sequencing.\\nYear: 2014\\n\\nAbstract: Whole genome amplification (WGA) have been applied to single cell copy number variations (CNVs) analysis, which is a common genomic mutation associated with various diseases and provides new insight for the fields of biology and medicine. However, the WGA-induced bias based on multiple displacement amplification (MDA) significantly limits sensitivity and specificity for CNVs detection. To address the limitations, an empirical algorithm for CNVs detection at single cell level was developed. This proposed method consists of base call amplification, alig- nment and analysis to remove the MDA-induced bias. We generated and analyzed about 50G short read data sets based on MDAsim, a software to amplify the chromosome 21 into various coverage. Simulation experiments have shown that the coverage tended to be less than average in genomic GC-enriched (>45 %) regions, implying a significant amplification bias within these regions. Base substitution error frequencies with G > A transversion is being among the most frequent and C > T, G > T transversions are among the least frequent substitution errors. The estimated substitution was employed to compensate errors to correct bias readings.\",\n \"Title: SemIndex: Semantic-Aware Inverted Index.\\nYear: 2014\\n\\nAbstract: This paper focuses on the important problem of semantic-aware search in textual (structured, semi-structured, NoSQL) databases. This problem has emerged as a required extension of the standard containment keyword based query to meet user needs in textual databases and IR applications. We provide here a new approach, called SemIndex, that extends the standard inverted index by constructing a tight coupling inverted index graph that combines two main resources: a general purpose semantic network, and a standard inverted index on a collection of textual data. We also provide an extended query model and related processing algorithms with the help of SemIndex. To investigate its effectiveness, we set up experiments to test the performance of SemIndex. Preliminary results have demonstrated the effectiveness, scalability and optimality of our approach.\",\n \"Title: Robust beamforming for two-user MISO broadcasting channel with delayed CSIT\\nYear: 2014\\n\\nAbstract: Recently proposed MAT1 scheme achieves high degrees of freedom (DoF) by exploiting delayed channel state information at transmitter side (CSIT) and the concept of interference alignment (IA), where the interference vectors of different time slots are aligned. As the starting work, MAT scheme considers no flexibility when reconstructing symbols at the third time slot, which may lead to performance degradation once the channel varies. In this paper, a probabilistic optimization problem is proposed with the assumption that the unknown channel entries follow given distribution. Instead of maximizing the sum rate directly, we strive to maximize the signal power while keeping the high probability that the interference power is lower than a pre-specified threshold. The Monte Carlo simulation results show that the proposed scheme outperforms the MAT scheme and dual SINR scheme with various channel uncertainties.\",\n \"Title: A biped humanoid robot's gait planning method based on Artificial Immune Network\\nYear: 2014\\n\\nAbstract: A biped humanoid robot model with 12 degree of freedom is developed in this paper. To facilitate the gait pattern planning, the 3D inverted pendulum model and the ZMP are introduced to enable a human-like stable walking. Since the searching of best walk primitive is a multi-objective optimization problem, a modified aiNet Algorithm as well as SGA Algorithm is applied to the optimization process. Finally, the control parameters worked out by both algorithms are verified and compared in simulation. We find out that the result of aiNet provides the robot with better stability than SGA while they are similar in mobility.\",\n \"Title: On optimal strategies in protecting computer networks\\nYear: 2011\\n\\nAbstract: Strategies of defending a computer network against random attacks are modeled by probabilistic methods. A single-stage model is introduced to find the optimal allocation of the resources of the administrator when the network has multiple possible targets. The location of the actual attack is random, the probability of which can be assessed by the administrator from previous interactions with the attacker and based on intelligence information. The expected value and the variance are combined to find the certain equivalent of the outcome, which depends on the allocation of the resources of the administrator between the vulnerabilities of the network. The mathematical model is a nonconvex programming problem, so application of standard optimization techniques cannot guarantee global optimum. By introducing new decision variables the problem can be transformed into a convex problem, the optimal solutions of which can be determined by a simple algorithm by solving a single-variable monotonic equation. This procedure makes the administrator able to find optimal resource allocations very fast and therefore can respond almost instantaneously.\",\n \"Title: 125Mbps ultra-wideband system evaluation for cortical implant devices.\\nYear: 2012\\n\\nAbstract: This paper evaluates the performance of a 125Mbps Impulse Ratio Ultra-Wideband (IR-UWB) system for cortical implant devices by using low-Q inductive coil link operating in the near-field domain. We examine design tradeoffs between transmitted signal amplitude, reliability, noise and clock jitter. The IR-UWB system is modeled using measured parameters from a reported UWB transceiver implemented in 90nm-CMOS technology. Non-optimized inductive coupling coils with low-Q value for near-field data transmission are modeled in order to build a full channel from the transmitter (Tx) to the receiver (Rx). On-off keying (OOK) modulation is used together with a low-complexity convolutional error correcting code. The simulation results show that even though the low-Q coils decrease the amplitude of the received pulses, the UWB system can still achieve acceptable performance when error correction is used. These results predict that UWB is a good candidate for delivering high data rates in cortical implant devices.\",\n \"Title: Automated exploration of stable isomers of H(+)(H(2)O)(n) (n = 5-7) via ab initio calculations: An application of the anharmonic downward distortion following algorithm.\\nYear: 2009\\n\\nAbstract: Isomers of protonated water clusters H+(H2O)(n) (n = 5-7) have been explored on ab initio potential energy surfaces by means of the anharmonic downward distortion following algorithm. Totally, 9, 24, and 131 isomers for n = 5, 6, and 7, respectively, were located by the automatic exploration, and all of known important isomers previously reported by conventional geometry optimization approaches have been included in the present results. Moreover, structure transitions depending on n and temperature, which were observed by experimental studies, could be reproduced via thermodynamic simulation on the basis of the superposition approach and the present isomer sets. (C) 2008 Wiley Periodicals, Inc. J Comput Chem 30: 952-961, 2009\",\n \"Title: A human ECG identification system based on ensemble empirical mode decomposition.\\nYear: 2013\\n\\nAbstract: In this paper, a human electrocardiogram (ECG) identification system based on ensemble empirical mode decomposition (EEMD) is designed. A robust preprocessing method comprising noise elimination, heartbeat normalization and quality measurement is proposed to eliminate the effects of noise and heart rate variability. The system is independent of the heart rate. The ECG signal is decomposed into a number of intrinsic mode functions (IMFs) and Welch spectral analysis is used to extract the significant heartbeat signal features. Principal component analysis is used reduce the dimensionality of the feature space, and the K-nearest neighbors (K-NN) method is applied as the classifier tool. The proposed human ECG identification system was tested on standard MIT-BIH ECG databases: the ST change database, the long-term ST database, and the PTB database. The system achieved an identification accuracy of 95% for 90 subjects, demonstrating the effectiveness of the proposed method in terms of accuracy and robustness.\",\n \"Title: Modeling the Strategic Behavior of Drivers for Multi-Lane Highway Driving\\nYear: 2015\\n\\nAbstract: Current state-of-the-art highway traffic flow simulators rely extensively on models using formulas similar to those describing physical phenomena, such as forces, viscosity, or potential fields. These models have been carefully calibrated to represent the overall flow of traffic and they can also be extended to account for the cognitive limitations of the driver, such as reaction times. However, there are some aspects of driver behavior, such as strategic planning, that are difficult to formulate mathematically. In this article, we describe the YAES-DSIM highway simulator, which integrates virtual physics models with an agent-based model. The virtual physics component models the physical vehicle and the subconscious aspects of the driver behavior, while the agent component is responsible for the strategic and tactical decisions, which are difficult to model using virtual physics. We focus on the lane change decisions of the drivers, with special attention to the optimal lane positioning for a safe exit. We have used the model to simulate the flow of traffic on Highway 408 in Orlando, Florida, and to study the impact of various tactical and strategic decisions on the efficiency and safety of the traffic.\",\n \"Title: Analysis of the information theoretically secret key agreement by public discussion\\nYear: 2015\\n\\nAbstract: Generally, the information theoretically secret key agreement by public discussion consists of three phases, namely, advantage distillation, information reconciliation, and privacy amplification. In the existing literatures, these three phases are studied separately, and no comprehensive consideration has been given. In this paper, we analyze the restrictive relationship among these three phases from an overall point of view. For the satellite scenario, we analyze in detail the Winnow protocol for the first time. We also present the mutual restrictive relationship between the parameters of the advantage distillation phase and the information reconciliation phase. We further address how to set the parameters of the advantage distillation and the information reconciliation to maximize the total secret key agreement efficiency. Moreover, we determine the required length range of the initial random key string to guarantee the validation of the secret key agreement. Copyright © 2015 John Wiley & Sons, Ltd.\",\n \"Title: Identification of sex-associated network patterns in Vaccine-Adverse Event Association Network in VAERS\\nYear: 2015\\n\\nAbstract: We have developed a network-based approach to investigate the vaccine-AE association network from the VAERS data. To our knowledge, this is the first time that a network-based approach was used to identify sex-specific association patterns in a spontaneous reporting system database. Due to unique limitations of such passive surveillance systems, our proposed network-based approaches have the potential to summarize and analyze the associations in passive surveillance systems by (1) identifying nodes of importance, irrespective of whether they are disproportionally reported; (2) providing guidance on sex-specific recommendations in personalized vaccinology.\",\n \"Title: Remote Sensing Of Regional Crop Transpiration Of Winter Wheat Based On Modis Data And Fao-56 Crop Coefficient Method\\nYear: 2013\\n\\nAbstract: Crop evapotranspiration is one of the most important parameters of farmland water cycle, which consists of crop transpiration (T-c) and soil evaporation. As the efficient component for crop production, T-c and its accurate determination, especially on a regional scale, is very critical for scientific design of irrigation scheduling and high-efficiency utilization of water resources. In this work, the T-c of winter wheat over an irrigation area located in the lower Yellow River of China was estimated by combining MODIS data and FAO-56 crop coefficient method. Specifically, the relationships between the single crop coefficient (K-c), basal crop coefficient (K-cb) and canopy vegetation indices were investigated and compared based on field data. Then, the actual K-cb map of winter wheat over the study area was estimated with MODIS-derived soil adjusted vegetation index (SAW) using the relationship obtained from above field investigations. Finally, the T-c of winter wheat over the area was determined as the product of K-cb and reference crop evapotranspiration (ET0). ET0 was calculated from meteorological data, and then were spatially interpolated to obtain the regional map matching with the remotely sensed K-cb. It was found that compared with K-c, K-cb was much more closely related to the vegetation indices of NDVI, SAVI, and EVI, even in the presence of nitrogen and water stress, with the coefficients of determination (R-2) being 0.60, 0.67 and 0.68 respectively (n = 195) which could be even higher without the water-stress points that had not reached the severity to make obvious changes in canopies. Results also demonstrated that it was feasible to utilize the K-cb-SAVI relationship to derive the K-cb of winter wheat over a large area by means of satellite remote sensing, and that it was effective to determine regional crop T-c using the above approach. It would be useful in practical application due to the advantages of easy operation and separating soil evaporation effectively.\",\n \"Title: Leading in the digital age: A study of how social media are transforming the work of communication professionals\\nYear: 2016\\n\\nAbstract: •Communication professionals used social media extensively in their work.•Social media use was closely related to professionals’ leadership behaviors.•Demographics and psychographics impacted professionals’ social media management.•Communication professionals’ strategic vision predicted their social media use.\",\n \"Title: Using peristaltic pump to charge micro heat pipe for high-power LED\\nYear: 2015\\n\\nAbstract: A novel perfusion method of micro heat pipe(MHP) is presented in this paper. The MHP has length of 26mm, width of 20 mm, and thickness of approximate 2.2mm. The predetermined quantity of perfusion is 25µl. Small volume and large capillary force render conventional vacuum perfusion methods quite impractical. In order to realize microscale and high precision of perfusion, the method of combining the vacuum perfusion using peristaltic pump and weight comparison before and after working fluid charging together was used. The charging deviation of the method was less than 2µl. And after perfusion and sealing, the thermal performance testing of MHP, which is engineered in LED heap dissipation, was conducted and the input power varied from 1W to 7W. The results show that high power LED can reach the status of heat balance and can work steadily. Therefore, this perfusion method can be used to working fluid perfusion of MHP and makes it feasible that it is used for packaging manufacture of heat pipe.\",\n \"Title: Throughput Of Two-Tier Heterogeneous Wireless Networks With Interference Coordination\\nYear: 2014\\n\\nAbstract: Two-tier heterogeneous wireless networks are considered in this paper where nodes in the first tier are distributed as a Poisson Point Process (PPP). Nodes in the second tier are distributed as a Poisson Clustered Process (PCP). Nodes in the second tier have imperfect channel state information (CSI) of the first tier node whose Voronoi cell they are in. On one hand, cross-tier interference is coordinated to the second tier nodes by interference alignment (IA) approach, where we strike a balance between increasing the number of data streams and increasing signal-to-interference (SIR) ratio at each data stream. On the other hand, the remaining interference is modelled by stochastic geometry and analytic expressions of throughput are derived. Monte Carlo simulations validate our expressions and show the gain brought by the interference coordination approach.\",\n \"Title: Measurement of subsidence in the Yangbajing geothermal fields, Tibet, from TerraSAR-X InSAR time series analysis.\\nYear: 2016\\n\\nAbstract: Yangbajain contains the largest geothermal energy power station in China. Geothermal explorations in Yangbajain first started in 1976, and two plants were subsequently built in 1981 and 1986. A large amount of geothermal fluids have been extracted since then, leading to considerable surface subsidence around the geothermal fields. In this paper, InSAR time series analysis is applied to map the subsidence of the Yangbajain geothermal fields during the period from December 2011 to November 2012 using 16 senses of TerraSAR-X stripmap SAR images. In the case of the TerraSAR-X data, most orbital fringes were removed using precise orbits during the interferometric processing. However, residual orbital ramps remain in some interferograms due to the uncertainties in the TerraSAR-X orbits. To remove the residual orbital ramps, we estimated a best-fit `twisted plane' for each epoch interferogram using quadratic polynomial models based on a network approach. This method removes most of the long-wavelength signals, including orbit ramps and atmospheric effects. The vertically stratified component (Topography Correlated Atmospheric Delay, TCAD) was also removed using a network approach. If the influence of seasonal frozen ground (SFG) is not taken into consideration, our results show that the subsidence rate around power plant I (the south plant) is approximately 20 mm/yr with a peak of 30 mm/yr. The subsidence rate around power plant II (the north plant) is approximately 10 mm/yr, when accounting for the influence of SFG on the power plant and its surrounding ground surface. Our results show that ground motion is caused by seasonal frozen ground and is strongly related to the temperature change.\",\n \"Title: Deep clustering and conventional networks for music separation: Stronger together\\nYear: 2017\\n\\nAbstract: Deep clustering is the first method to handle general audio separation scenarios with multiple sources of the same type and an arbitrary number of sources, performing impressively in speaker-independent speech separation tasks. However, little is known about its effectiveness in other challenging situations such as music source separation. Contrary to conventional networks that directly estimate the source signals, deep clustering generates an embedding for each time-frequency bin, and separates sources by clustering the bins in the embedding space. We show that deep clustering outperforms conventional networks on a singing voice separation task, in both matched and mismatched conditions, even though conventional networks have the advantage of end-to-end training for best signal approximation, presumably because its more flexible objective engenders better regularization. Since the strengths of deep clustering and conventional network architectures appear complementary, we explore combining them in a single hybrid network trained via an approach akin to multi-task learning. Remarkably, the combination significantly outperforms either of its components.\",\n \"Title: Deep attractor network for single-microphone speaker separation\\nYear: 2017\\n\\nAbstract: Despite the overwhelming success of deep learning in various speech processing tasks, the problem of separating simultaneous speakers in a mixture remains challenging. Two major difficulties in such systems are the arbitrary source permutation and unknown number of sources in the mixture. We propose a novel deep learning framework for single channel speech separation by creating attractor points in high dimensional embedding space of the acoustic signals which pull together the time-frequency bins corresponding to each source. Attractor points in this study are created by finding the centroids of the sources in the embedding space, which are subsequently used to determine the similarity of each bin in the mixture to each source. The network is then trained to minimize the reconstruction error of each source by optimizing the embeddings. The proposed model is different from prior works in that it implements an end-to-end training, and it does not depend on the number of sources in the mixture. Two strategies are explored in the test time, K-means and fixed attractor points, where the latter requires no post-processing and can be implemented in real-time. We evaluated our system on Wall Street Journal dataset and show 5.49% improvement over the previous state-of-the-art methods.\",\n \"Title: Linking Heterogeneous Data in the Semantic Web Using Scalable and Domain-Independent Candidate Selection.\\nYear: 2017\\n\\nAbstract: Due to the decentralized nature of the Semantic Web, the same real-world entity may be described in various data sources with different ontologies and assigned syntactically distinct identifiers. In order to facilitate data utilization and consumption in the Semantic Web, without compromising the freedom of people to publish their data, one critical problem is to appropriately interlink such heterogeneous data. This interlinking process is sometimes referred to as Entity Matching, i.e., finding which identifiers refer to the same real-world entity. In this paper, we propose two candidate selection algorithms to improve the scalability of entity matching systems. First of all, we propose HistSim that utilizes the matching histories of the instances to prune instance pairs that are not sufficiently similar to the same pool of other instances. A sigmoid function based thresholding method is proposed to automatically adjust the threshold for such commonality on-the-fly. Furthermore, we propose DisNGram that selects candidate instance pairs by computing a character-level similarity metric on discriminating literal values that are chosen using domain-independent unsupervised learning. Instances are indexed on the chosen predicates’ literal values to enable efficient look-up for similar instances. Finally, in order to be able to handle heterogeneous datasets with a large number of predicates, a mechanism for automatically determining predicate comparability is proposed. We evaluate our two candidate selection algorithms against six state-of-the-art systems on three Semantic Web datasets, and demonstrate that our proposed algorithms frequently outperform state-of-the-art systems on F1-score and runtime.\",\n \"Title: A CMOS pixel design with binary space-time exposure encoding for computational imaging\\nYear: 2017\\n\\nAbstract: A CMOS pixel design that is capable of spatialtemporal exposure encoding is presented. By integrating selective charge storage units and exposure code memories in an active pixel sensor (APS) structure, the 10 μm×10 μm pixel design performs intermittent exposure according to the received binary exposure codes. Under a 625 nm illumination and with a 3.3 V supply, a 10×10 prototype image sensor fabricated in a 0.13-μm CMOS process demonstrates temporal, spatial, and spatialtemporal exposure encoding at 60 fps. The proposed pixel structure facilitates focal-plane space-time exposure encoding in CMOS image sensors for computational imaging applications.\",\n \"Title: Optimal Lateral Trajectory Tracking using Backstepping with a Fully Tuned Growing RBF Neural Network.\\nYear: 2012\\n\\nAbstract: This paper will present an approach to aircraft lateral trajectory tracking utilizing backstepping control with a fully-tuned Growing Radial Basis Function (GRBF) neural network. The aircraft lateral trajectory is generated via optimization of a cost functional using the Pontryagin maximum principle. The fully tuned growing RBF network is utilized to compensate for unknown perturbations in the aircraft model. Simulations are presented for an optimal turn and descent trajectory.\",\n \"Title: Always-on CMOS image sensor pixel design for pixel-wise binary coded exposure.\\nYear: 2017\\n\\nAbstract: Pixel-wise coded exposure, as an emerging field of research in computational imaging, is widely implemented in applications such as high-speed imaging, compressive sensing, and focal-stack imaging. In this paper, a complementary metal-oxide-semiconductor (CMOS) pixel design for binary coded exposure is presented. Based on an always-on charge distribution structure, the proposed pixel achieves programmable charge selection. A prototype image sensor chip, fabricated in a 0.13-μm CMOS process demonstrates pixelu0027s capability of binary exposure encoding in 60 fps while operating from a 3.3 V supply.\",\n \"Title: Feasibility analysis of data transmission in SDN.\\nYear: 2017\\n\\nAbstract: In the setting of software definition network (SDN), whether there exists an available transmission plan between any two sites is equal to whether there exists a fractional factor after deleting certain vertices and edges in the corresponding graph. A graphGis called a fractional ID-(a, b, m)-deleted graph if after deleting any independent-set I, the remaining graph G - I is a fractional (a, b, m)-deleted graph. A fractional (g, f)-factor F of a graph G is called a Hamiltonian fractional (g, f)-factor if F includes a Hamiltonian cycle. Furthermore, we say that G has a ID-Hamiltonian fractional (g, f)-factor if after deleting any independent set of G the remaining graph of G includes a Hamiltonian fractional (g, f)-factor. In this paper, we first give a binding number condition for a graph to be a fractional ID-(a, b, m)-deleted graph, and then two sufficient conditions for graphs to have ID-Hamiltonian fractional (g, f)-factors are obtained.\",\n \"Title: A Small UAV Based Multi-Temporal Image Registration for Dynamic Agricultural Terrace Monitoring.\\nYear: 2017\\n\\nAbstract: Terraces are the major land-use type of agriculture and support the main agricultural production in southeast and southwest China. However, due to smallholder farming, complex terrains, natural disasters and illegal land occupations, a light-weight and low cost dynamic monitoring of agricultural terraces has become a serious concern for smallholder production systems in the above area. In this work, we propose a small unmanned aerial vehicle (UAV) based multi-temporal image registration method that plays an important role in transforming multi-temporal images into one coordinate system and determines the effectiveness of the subsequent change detection for dynamic agricultural terrace monitoring. The proposed method consists of four steps: (i) guided image filtering based agricultural terrace image preprocessing, (ii) texture and geometric structure features extraction and combination, (iii) multi-feature guided point set registration, and (iv) feature points based image registration. We evaluated the performance of the proposed method by 20 pairs of aerial images captured from Longji and Yunhe terraces, China using a small UAV (the DJI Phantom 4 Pro), and also compared against four state-of-the-art methods where our method shows the best alignments in most cases.\",\n \"Title: Nonrigid Image Registration for Low-Altitude SUAV Images With Large Viewpoint Changes.\\nYear: 2018\\n\\nAbstract: Low-altitude aerial photography using small unmanned aerial vehicles (SUAVs) with large viewpoint changes causes nonrigid distortions and low overlap ratios. We present a nonrigid feature-based low-altitude SUAV image-registration method. The key idea of our method is to maintain a high matching ratio on inliers while taking advantage of outliers for varying the warping grids. Thus, accurate image...\",\n \"Title: Speaker-Independent Speech Separation With Deep Attractor Network.\\nYear: 2018\\n\\nAbstract: Despite the recent success of deep learning for many speech processing tasks, single-microphone, speaker-independent speech separation remains challenging for two main reasons. The first reason is the arbitrary order of the target and masker speakers in the mixture (permutation problem), and the second is the unknown number of speakers in the mixture (output dimension problem). We propose a novel ...\",\n \"Title: Secure and Efficient Access Control Scheme for Wireless Sensor Networks in the Cross-Domain Context of the IoT.\\nYear: 2018\\n\\nAbstract: Nowadays wireless sensor network (WSN) is increasingly being used in the Internet of Things (IoT) for data collection, and design of an access control scheme that allows an Internet user as part of IoT to access the WSN becomes a hot topic. A lot of access control schemes have been proposed for the WSNs in the context of the IoT. Nevertheless, almost all of these schemes assume that communication nodes in different network domains share common system parameters, which is not suitable for cross-domain IoT environment in practical situations. To solve this shortcoming, we propose a more secure and efficient access control scheme for wireless sensor networks in the cross-domain context of the Internet of Things, which allows an Internet user in a certificateless cryptography (CLC) environment to communicate with a sensor node in an identity-based cryptography (IBC) environment with different system parameters. Moreover, our proposed scheme achieves known session-specific temporary information security (KSSTIS) that most of access control schemes cannot satisfy. Performance analysis is given to show that our scheme is well suited for wireless sensor networks in the cross-domain context of the IoT.\",\n \"Title: Multi-Parameter-Setting Based On Data Original Distribution For Denclue Optimization\\nYear: 2018\\n\\nAbstract: DENCLUE is a typical density-based clustering method, and it also is an important pattern classification analysis technique. In this clustering method, the propriety of parameters' values greatly infiuences the quality of distinguishing. Accordingly, how to choose an appropriate value of every parameter is a problem that is worth studying. The problem is focused in this paper, and a method which is very different from previous ones is presented. The highlight of the method is that the selection of parameters no longer depends on personal experience but on data original distribution. More specifically, smoothing parameter h is more or less proportional to the average value of distance between two arbitrary data points; step size delta is adapted according to the density of data points in the hill-climbing progress; noise threshold xi is replaced by delta and total number of data points. Compared with the original DENCLUE and an improved DENCLUE proposed in our previous research, the optimized algorithm can bring better clustering from experiments. In addition, due to the adaptiveness of delta, the method will become less complex.\",\n \"Title: Exposure-Programmable CMOS Pixel With Selective Charge Storage and Code Memory for Computational Imaging.\\nYear: 2018\\n\\nAbstract: Computational imaging, as a rapid emerging field, enables unprecedented photographic capability through the encoding of visual information. Currently, as exposure programming is not support by image sensors, computational cameras use off-chip components to accomplish exposure/encoding optical computations. In this paper, we present a complementary metal-oxide-semiconductor (CMOS) pixel structure w...\",\n \"Title: Chaotic behavior of discrete-time linear inclusion dynamical systems.\\nYear: 2017\\n\\nAbstract: Given any finite family of real d-by-d nonsingular matrices {S1,…,Sl}, by extending the well-known Li–Yorke chaos of a deterministic nonlinear dynamical system to a discrete-time linear inclusion or hybrid or switched system:\\nxn∈{Skxn−1;1≤k≤l},x0∈Rdandn≥1,we study the chaotic dynamics of the state trajectory (xn(x0, σ))n ≥ 1 with initial state x0∈Rd, governed by a switching law σ:N→{1,…,l}. Two sufficient conditions are given so that for a “large” set of switching laws σ, there exhibits the scrambled dynamics as follows: for all x0,y0∈Rd,x0≠y0,lim infn→+∞∥xn(x0,σ)−xn(y0,σ)∥=0andlim supn→+∞∥xn(x0,σ)−xn(y0,σ)∥=∞.This implies that there coexist positive, zero and negative Lyapunov exponents and that the trajectories (xn(x0, σ))n ≥ 1 are extremely sensitive to the initial states x0∈Rd. We also show that a periodically stable linear inclusion system, which may be product unbounded, does not exhibit any such chaotic behavior. An explicit simple example shows the discontinuity of Lyapunov exponents with respect to the switching laws.\",\n \"Title: Non-rigid point set registration using dual-feature finite mixture model and global-local structural preservation.\\nYear: 2018\\n\\nAbstract: •We develop a dual-feature finite mixture model based point set registration method.•We define a local structure descriptor.•We constrain the energy function using both the global and local structural regularization terms, preserving the structure at both global and local scales during the registration.•The performance of our method outperforms state-of-art methods in this area.\",\n \"Title: Interference Alignment in Two-Tier Randomly Distributed Heterogeneous Wireless Networks Using Stochastic Geometry Approach.\\nYear: 2018\\n\\nAbstract: With the massive increase in wireless data traffic in recent years, multi-tier wireless networks have been deployed to provide much higher capacities and coverage. However, heterogeneity of wireless networks bring new challenges for interference analysis and coordination due to spatial randomly distributed transmitters. In this paper, we present a distance-dependent interference alignment (IA) app...\",\n \"Title: Three-Layer Bayesian Network for Classification of Complex Power Quality Disturbances.\\nYear: 2018\\n\\nAbstract: In this paper, a new classification approach for detection and classification of complex power quality disturbances (PQDs) using a three-level multiply connected Bayesian network is proposed. First, the model consisting of features evidence layer, disturbances state layer, and circumstance evidence layer is established, which represent the features extracted from the sample signal, the state of ea...\",\n \"Title: Response to Comment on \\\"All-optical machine learning using diffractive deep neural networks\\\".\\nYear: 2018\\n\\nAbstract: In their Comment, Wei et al. (arXiv:1809.08360v1 [cs.LG]) claim that our original interpretation of Diffractive Deep Neural Networks (D2NN) represent a mischaracterization of the system due to linearity and passivity. In this Response, we detail how this mischaracterization claim is unwarranted and oblivious to several sections detailed in our original manuscript (Science, DOI: 10.1126/science.aat8084) that specifically introduced and discussed optical nonlinearities and reconfigurability of D2NNs, as part of our proposed framework to enhance its performance. To further refute the mischaracterization claim of Wei et al., we, once again, demonstrate the depth feature of optical D2NNs by showing that multiple diffractive layers operating collectively within a D2NN present additional degrees-of-freedom compared to a single diffractive layer to achieve better classification accuracy, as well as improved output signal contrast and diffraction efficiency as the number of diffractive layers increase, showing the deepness of a D2NN, and its inherent depth advantage for improved performance. In summary, the Comment by Wei et al. does not provide an amendment to the original teachings of our original manuscript, and all of our results, core conclusions and methodology of research reported in Science (DOI: 10.1126/science.aat8084) remain entirely valid.\",\n \"Title: TasNet: Surpassing Ideal Time-Frequency Masking for Speech Separation.\\nYear: 2018\\n\\nAbstract: Robust speech processing in multitalker acoustic environments requires automatic speech separation. While single-channel, speaker-independent speech separation methods have recently seen great progress, the accuracy, latency, and computational cost of speech separation remain insufficient. The majority of the previous methods have formulated the separation problem through the time-frequency representation of the mixed signal, which has several drawbacks, including the decoupling of the phase and magnitude of the signal, the suboptimality of spectrogram representations for speech separation, and the long latency in calculating the spectrogram. To address these shortcomings, we propose the time-domain audio separation network (TasNet), which is a deep learning autoencoder framework for time-domain speech separation. TasNet uses a convolutional encoder to create a representation of the signal that is optimized for extracting individual speakers. Speaker extraction is achieved by applying a weighting function (mask) to the encoder output. The modified encoder representation is then inverted to the sound waveform using a linear decoder. The masks are found using a temporal convolutional network consisting of dilated convolutions, which allow the network to model the long-term dependencies of the speech signal. This end-to-end speech separation algorithm significantly outperforms previous time-frequency methods in terms of separating speakers in mixed audio, even when compared to the separation accuracy achieved with the ideal time-frequency mask of the speakers. In addition, TasNet has a smaller model size and a shorter minimum latency, making it a suitable solution for both offline and real-time speech separation applications. This study therefore represents a major step toward actualizing speech separation for real-world speech processing technologies.\",\n \"Title: The Spatial And Temporal Variation Of Land Use In Dianchi Basin Under The Policy Driven By Urban Establishment Up At Mountain\\nYear: 2018\\n\\nAbstract: land use cover change (LUCC) is an important factor affecting the environment as well as a complex process of human activities. Analysis of LUCC has a positive impact on improving the environment. This study analyzed the spatial and temporal distribution of LUCC in Dianchi basin in recent 20 years and use DEM (Digital Elevation Model) data, take advantage of spatial analysis capabilities in ArcGis, Explore the change of LUCC in Dianchi basin on the \\\"Urban establishment up at mountain \\\" policy. The results show that in the past 20 years, the LUCC in Dianchi basin is influenced by the environment, but the policy-driven effect is more significant; The amount of land used for urban construction increased by 187.07km(2) at low elevation and 285.79km (2) at low-middle-elevation respectively, and the growth rate of areas at medium and high altitude gradually increased. The woodland (WL) decreases first and then increases, the grassland increases first and then decreases and grassland from boundary moves to the center of the built-up area, and the change amplitude increases; The area of cropland (CL) in the marginal area of Dianchi Lake shows a decreasing trend; All kinds of land conversion relations are complex, but they all show the transformation to urban construction; Urban construction with the \\\" Urban establishment up at mountain \\\" policy driven by the apparent low elevation to the high altitude transfer trend, and speed up.\",\n \"Title: Spatial And Temporal Analysis Of Educational Development In Yunnan On The Last Two Decades\\nYear: 2018\\n\\nAbstract: This paper attempts to find out the space-time law of educational development in different regions by constructing a new method and in the absence of educational quality monitoring system. Based on the analysis of the existing education quality monitoring system, this paper explores and cleans up historical data, and uses the theory of social science research, mathematical statistical analysis and geographic information thinking to study the relevant regions. Research shows that overall education in Yunnan is developing well but there are still improvements in basic education.\",\n \"Title: Present Situation And Trend Of Remote Sensing Land Use/Cover Classification Extraction\\nYear: 2018\\n\\nAbstract: To further advance the automatic process of land use/cover (LULC) classification extraction through remote sensing (RS) images, by reading many literatures, we summarized the problems, research difficulties and development trends in the process of information extraction and classification of land use. Overall, LULC Classification and extraction based on RS images include 3 tasks: data source selection, sampling design, classification method selection and classifier performance evaluation. These tasks are all important, that is, interdependence and mutual influence. The OBIC method has become a popular method of LULC classification because it makes full use of geographic information system (GIS) technology to process spatial, spectral and textural features in RS images. There are many OBIC algorithms, especially the Machine learning (ML) algorithms offers the potential for effectiveness and efficiency, such as Random forest (RF), Support vector machine (SVM) and so on. The Object-based image classification (OBIC) method involves three stages: segmentation, feature-selection and classification. A large number of studies have proved that there are many problems in each task of the LCLU classification extraction method based on RS images. These problems include design of sample sampling strategy, determination of optimal image segmentation parameters and optimization of parameter of classification algorithm and so on. At present, solving these problems requires frequent human-computer interaction also has a great negative influence on the automatic extraction process of remote sensing classification. Using GIS technology to promote the automatic extraction of remote sensing classification has become a trend of the development of remote sensing classification method.\",\n \"Title: Study On The Temporal And Spatial Variation Of Pm2.5 In Eight Main Cities Of Yunnan Province\\nYear: 2018\\n\\nAbstract: Air haze pollution has a serious impact on human health, ecological environment and climate change. In recent years, with the introduction of new national policies and people's increasing awareness of environmental protection, haze has received widespread social attention. Haze pollution in China has always been a prominent environmental problem. The main reason for the frequent occurrence of haze pollution is PM2.5, which not only occurs in cities with high degree of industrialization or urbanization, but also often appear in regions with good air quality. This paper selects eight main cities in Yunnan Province as the research area, and uses the measured PM2.5 data from eight main cities in January 2015 to February 2018 in Yunnan Province as the basic data, using the eight urban meteorological data as the basic data, using the MK trend test and Correlation coefficient method to carry out research on the spatial-temporal variation and correlation of PM2.5 in the last three years in Yunnan Province. The space-time analysis shows that the average annual PM2.5 concentration in Lijiang City is the lowest, the monthly average concentration in Baoshan City is the highest, and the daily average concentration in Puer City is in a gentle trend; Except for Lijiang, the other seven cities all experienced different levels of pollution from March 17 to March 26, 2015; The concentration of PM2.5 in each city showed a seasonal pattern of \\\"U\\\" and a pulse-like diurnal variation pattern in winter and spring, summer and autumn; cities with higher annual average concentrations in the province are concentrated in the northeast and southwest. Correlation analysis showed that PM2.5 concentration was significantly negatively correlated with precipitation and wind speed, and negatively correlated with daily average humidity and temperature.\",\n \"Title: Study And Analysis The Spatial Influence Of Intercity Interaction\\nYear: 2018\\n\\nAbstract: In the study of geography, the intensity of interaction between two objects affected by distance is called spatial influence. The study of spatial influence is a concrete description and analysis of spatial interaction problems in the study of geography and regional economics, and it also summarizes analytical methods for spatial influence. According to the Tobler's First Law of Geography, the spatial interaction is affected by distance. Therefore, based on the Gravity Model, this paper discusses the distance decay function to analyze the situation and change of interaction strength between objects under the influence of distance. The field spread model is used to analyze the spatial attractiveness and radiation force of the city. The Breakpoint Theory reflects the specific strength of the intercity connections, especially the attraction of surrounding cities at the Breaking Point. These methods provide theoretical basis for urban regional planning, and have important practical significance for the sustainable development of cities in the future.\",\n \"Title: Urban Road Image Segmentation Algorithm Based On Statistical Information\\nYear: 2018\\n\\nAbstract: Urban road image segmentation is an important technology of intelligent city management and pilotless driving. In order to improve the effect of image segmentation, direct at the deficiency of single seed point and fixed threshold of traditional region growing algorithm, a seed selection method based on the gray level of two-dimensional histogram and local variance is proposed, and the dynamic threshold is used to change the region growing rule. The experimental results show that the seeds selected by this method can be highly representative, and realize the complete segmentation of the image. Based on the dynamic threshold region growth rule, the image segmentation has a better effect.\",\n \"Title: Using Sequential Gaussian Simulation to Assess the Spatial Uncertainty of PM<inf>2.5</inf> in China\\nYear: 2018\\n\\nAbstract: Based on the observed PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n concentration data in 2016, ordinary kriging (OK) and sequential Gaussian simulation (SGS) were used to map spatial distribution of PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n in China, and SGS can model not only single, but also multi-location uncertainties, which assess the uncertainty of the PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n spatial distribution. A smoothing effect was produced when using OK technique in mapping of PM2.5, however relatively discrete and fluctuant map was obtained by the SGS. Their results of spatial distribution show that east and west regions have higher PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n concentration, middle regions have lower concentration in China. Based on the SGS realization, the probability that PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n concentration at single location was higher than the defined threshold (10μg/m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n) was big for the whole study area. The minimum value was 0.77. When the defined threshold changed to 35 μg/m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n, the extent of higher probability was shrunk, the bigger value (0.8-1) existed in Xinjiang and North China. The probability which PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n concentrations were higher than the defined threshold in several locations at the same time was also called joint probability. Given the critical probabilities (pm=1 and> 0.98), joint probability of PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n in area a being higher than 10μg/m3 respectively is 0.85 and 0.5; while joint probability of PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\nin area a being higher than 35μg/m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n respectively is 0. 65 and 0.14. The probability map can be very helpful for controlling and making environmental management decision of PM\\n<sub xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2.5</sub>\\n pollution.\",\n \"Title: Adversarial Defense of Image Classification Using a Variational Auto-Encoder.\\nYear: 2018\\n\\nAbstract: Deep neural networks are known to be vulnerable to adversarial attacks. This exposes them to potential exploits in security-sensitive applications and highlights their lack of robustness. This paper uses a variational auto-encoder (VAE) to defend against adversarial attacks for image classification tasks. This VAE defense has a few nice properties: (1) it is quite flexible and its use of randomness makes it harder to attack; (2) it can learn disentangled representations that prevent blurry reconstruction; and (3) a patch-wise VAE defense strategy is used that does not require retraining for different size images. For moderate to severe attacks, this system outperforms or closely matches the performance of JPEG compression, with the best quality parameter. It also has more flexibility and potential for improvement via training.\",\n \"Title: Redesigning a Software Development Course as a Preparation for a Capstone: An Experience Report\\nYear: 2019\\n\\nAbstract: Students need a wide variety of skills before they can successfully engage in real-world projects with paying customers. Some of these skills, such as the \\\"soft skills\\\" of communicating with a non-technical customer and working in a larger team to collaboratively develop a project, are generally not present in Computer Science courses. In this paper, we discuss our experience teaching these skills and explain the structure of our redesigned Software Development course and how it aligns with the Capstone experience. The main novelty of our approach is the specific implementation of the rotating project manager role and the introduction of the final portfolio reflection. We believe that the concepts we introduced during our redesign can be useful to any educator wanting to include collaborative project-based work in their courses. To enable faculty to apply and enhance these concepts, the resources that we used in this course, which include activities, templates, guidelines, rubrics, and questionnaires, are available as an open source project at https://team-repo.github.io/.\",\n \"Title: A fictitious play-based response strategy for multistage intrusion defense systems\\nYear: 2014\\n\\nAbstract: AbstractThe recent developments of advanced intrusion detection systems in the cyber security field provide opportunities to proactively protect the computer network systems and minimize the impacts of attackers on network operations. This paper is intended to assist the network defender find its best actions to defend against multistage attacks. The possible sequences of interactions between the attackers and the network defender are modeled as a two-player non-zero-sum non-cooperative dynamic multistage game with incomplete information. The players are assumed to be rational. They take turns in making decisions by considering previous and possible future interactions with the opponent and use Bayesian analysis after each interaction to update their knowledge about the opponents. We propose a Dynamic game tree-based Fictitious Play DFP approach to describe the repeated interactive decisions of the players. Each player finds its best moves at its decision nodes of the game tree by using multi-objective analysis. All possibilities are considered with their uncertain future interactions, which are based on learning of the opponent's decision process including risk attitude and objectives. Instead of searching the entire game tree, appropriate future time horizons are dynamically determined for both players. In the DFP approach, the defender keeps tracking the opponent's actions, predicts the probabilities of future possible attacks, and then chooses its best moves. Thus, a new defense algorithm, called Response by DFP RDFP, is developed. Numerical experiments show that this approach significantly reduces the damage caused by multistage attacks and it is also more efficient than other related algorithms. Copyright © 2013 John Wiley & Sons, Ltd.\",\n \"Title: Space Geodetic Observations and Modeling of 2016 Mw 5.9 Menyuan Earthquake: Implications on Seismogenic Tectonic Motion.\\nYear: 2016\\n\\nAbstract: Determining the relationship between crustal movement and faulting in thrust belts is essential for understanding the growth of geological structures and addressing the proposed models of a potential earthquake hazard. A Mw 5.9 earthquake occurred on 21 January 2016 in Menyuan, NE Qinghai Tibetan plateau. We combined satellite interferometry from Sentinel-1A Terrain Observation with Progressive Scans (TOPS) images, historical earthquake records, aftershock relocations and geological data to determine fault seismogenic structural geometry and its relationship with the Lenglongling faults. The results indicate that the reverse slip of the 2016 earthquake is distributed on a southwest dipping shovel-shaped fault segment. The main shock rupture was initiated at the deeper part of the fault plane. The focal mechanism of the 2016 earthquake is quite different from that of a previous Ms 6.5 earthquake which occurred in 1986. Both earthquakes occurred at the two ends of a secondary fault. Joint analysis of the 1986 and 2016 earthquakes and aftershocks distribution of the 2016 event reveals an intense connection with the tectonic deformation of the Lenglongling faults. Both earthquakes resulted from the left-lateral strike-slip of the Lenglongling fault zone and showed distinct focal mechanism characteristics. Under the shearing influence, the normal component is formed at the releasing bend of the western end of the secondary fault for the left-order alignment of the fault zone, while the thrust component is formed at the restraining bend of the east end for the right-order alignment of the fault zone. Seismic activity of this region suggests that the left-lateral strike-slip of the Lenglongling fault zone plays a significant role in adjustment of the tectonic deformation in the NE Tibetan plateau.\",\n \"Title: A Novel Algorithm For Abandoned Object Detection\\nYear: 2016\\n\\nAbstract: Abandoned object detection is a crucial problem in many computer vision tasks. Traditional method based on foreground/background extraction techniques leads to a high false alarm rate. In this paper, we propose a novel detection algorithm based on change detection and blob separation. Our proposed approach suits more practical scenarios in which objects located near each other. Experiments are conducted on several well-known benchmarks to validate the efficacy of the algorithm proposed in this paper.\",\n \"Title: A highly accurate and fast power quality disturbances classification based on dictionary learning sparse decomposition\\nYear: 2019\\n\\nAbstract: This paper proposes a highly accurate and fast power quality disturbances (PQDs) classification using dictionary learning sparse decomposition (DLSD). Firstly, an over-complete dictionary is constructed by combining an identity matrix with a learning dictionary trained by K-SVD algorithm. Secondly, the features and the fuzzy primary classifications of PQDs are obtained by calculating the sparse decomposition coefficients based on the learning dictionary. For being adaptive to sparsity and reducing computational complexity, a fast adaptive matching pursuit (FAMP) using sparsity adaptive algorithm and regularized atom selection is proposed. Then, a decision tree is adopted to accomplish accurate classification by using the estimated features and the pre-classification results. Finally, the proposed approach is tested by PQDs from simulations, IEEE PES database and actual measurements. Moreover, several testing signals, which contain strong noise and frequency deviation, are introduced to further validate DLSD. The results demonstrate that DLSD has a good improvement on computational complexity and classification accuracy when dealing with PQDs classification.\",\n \"Title: Maximized Mutual Information Analysis Based on Stochastic Representation for Process Monitoring\\nYear: 2019\\n\\nAbstract: This paper proposes a stochastic representation of maximized mutual information analysis (MIA) method for quality monitoring in which a manner of imposing prior probability distributions over projection parameters is employed and subsequently, a Bayesian estimation algorithm is put forward for projection learning. The proposed stochastic MIA (SMIA) based approach allows the enhanced performance of fault detection due to the following advantages over classic monitoring methods. First, the SMIA approach utilizes the mechanism of hierarchical priors and an individual prior over each projection direction, as a key feature of the proposed method, which enables SMIA to build a sparse model that can discard irrelevant components in the process data with respect to the prediction of quality variables. Second, the proposed SMIA method incorporates the advantage of maximizing mutual information on the minimum achievable error of model prediction as well as the advantage of describing the serial dynamics. Additionally, the optimal dimensionality of the latent space in an SMIA can be automatically determined during the procedure of Bayesian estimation by the utilization of these adaptive priors over projections. The effectiveness of the proposed approach for quality monitoring is demonstrated on the benchmark of Tennessee Eastman process.\",\n \"Title: Novel Method Based on Variational Mode Decomposition and a Random Discriminative Projection Extreme Learning Machine for Multiple Power Quality Disturbance Recognition\\nYear: 2019\\n\\nAbstract: Power quality events are usually associated with more than one disturbance and their recognition is typically based on multilabel learning. In this study, we propose a new method for recognizing multiple power quality disturbances (MPQDs) based on variational mode decomposition (VMD) and a random discriminative projection extreme learning machine for multilabel learning (RDPEML). First, VMD is employed to decompose the MPQDs into several intrinsic mode functions and the standard energy differences of each mode are extracted as features that form the input vectors of the classifier. Second, a novel multilabel classifier called RDPEML is constructed by combining a random discriminative projection multiclass extreme learning machine (ELM) and a thresholding learning method-based kernel ELM. In order to obtain better classification performance, a tenfold cross-validation embedded particle swarm optimization approach is utilized to search for the optimal values of the structural parameters. Finally, a test study was conducted using MATLAB synthetic signals and real signals sampled from a three-phase standard source under different noise conditions. Compared with the several recent state-of-the-art multilabel learning algorithms, RDPEML achieved better classification performance with superior computational speed.\",\n \"Title: Analysis of Diffractive Optical Neural Networks and Their Integration with Electronic Neural Networks.\\nYear: 2018\\n\\nAbstract: Optical machine learning offers advantages in terms of power efficiency, scalability, and computation speed. Recently, an optical machine learning method based on diffractive deep neural networks (D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNNs) has been introduced to execute a function as the input light diffracts through passive layers, designed by deep learning using a computer. Here, we introduce improvements to D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNNs by changing the training loss function and reducing the impact of vanishing gradients in the error back-propagation step. Using five phase-only diffractive layers, we numerically achieved a classification accuracy of 97.18% and 89.13% for optical recognition of handwritten digits and fashion products, respectively; using both phase and amplitude modulation (complex-valued) at each layer, our inference performance improved to 97.81% and 89.32%, respectively. Furthermore, we report the integration of D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNNs with electronic neural networks to create hybrid classifiers that significantly reduce the number of input pixels into an electronic network using an ultra-compact front-end D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNN with a layer-to-layer distance of a few wavelengths, also reducing the complexity of the successive electronic network. Using a five-layer phase-only D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNN jointly optimized with a single fully connected electronic layer, we achieved a classification accuracy of 98.71% and 90.04% for the recognition of handwritten digits and fashion products, respectively. Moreover, the input to the electronic network was compressed by >7.8 times down to 10 × 10 pixels. Beyond creating low-power and high-frame rate machine learning platforms, D\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">2</sup>\\nNN-based hybrid neural networks will find applications in smart optical imager and sensor design.\",\n \"Title: Online Deep Attractor Network for Real-time Single-channel Speech Separation\\nYear: 2019\\n\\nAbstract: Speaker-independent speech separation is a challenging audio processing problem. In recent years, several deep learning algorithms have been proposed to address this problem. The majority of these methods use noncausal implementation which limits their application in real-time scenarios such as in wearable hearing devices and low-latency telecommunication. In this paper, we propose the Online Deep Attractor Network (ODANet), an extension to the Deep Attractor Network (DANet) which is causal and enables real-time speech separation. In contrast with DANet that estimates the global attractor point for each speaker using the entire utterance, ODANet estimates the attractors for each time step and tracks them using a dynamic weighting function with only causal information. This not only solves the speaker tracking problem, but also allows ODANet to generate more stable embeddings across time. Experimental results show that ODANet can achieve a similar separation accuracy as the noncausal DANet in both two speaker and three speaker speech separation problems, which makes it a suitable candidate for applications that require robust real-time speech processing.\",\n \"Title: Dynamic Demand Prediction for Expanding Electric Vehicle Sharing Systems: A Graph Sequence Learning Approach.\\nYear: 2019\\n\\nAbstract: Electric Vehicle (EV) sharing systems have recently experienced unprecedented growth across the globe. During their fast expansion, one fundamental determinant for success is the capability of dynamically predicting the demand of stations as the entire system is evolving continuously. There are several challenges in this dynamic demand prediction problem. Firstly, unlike most of the existing work which predicts demand only for static systems or at few stages of expansion, in the real world we often need to predict the demand as or even before stations are being deployed or closed, to provide information and support for decision making. Secondly, for the stations to be deployed, there is no historical record or additional mobility data available to help the prediction of their demand. Finally, the impact of deploying/closing stations to the remaining stations in the system can be very complex. To address these challenges, in this paper we propose a novel dynamic demand prediction approach based on graph sequence learning, which is able to model the dynamics during the system expansion and predict demand accordingly. We use a local temporal encoding process to handle the available historical data at individual stations, and a dynamic spatial encoding process to take correlations between stations into account with graph convolutional neural networks. The encoded features are fed to a multi-scale prediction network, which forecasts both the long-term expected demand of the stations and their instant demand in the near future. We evaluate the proposed approach on real-world data collected from a major EV sharing platform in Shanghai for one year. Experimental results demonstrate that our approach significantly outperforms the state of the art, showing up to three-fold performance gain in predicting demand for the rapidly expanding EV sharing system.\",\n \"Title: Three-Dimensional Computed Tomography Angiography Assisted Resection of Ventral Foramen Magnum and Jugular Foramen Tumours via Modified Far Lateral Suboccipital Approach\\nYear: 2019\\n\\nAbstract: Objective: The anatomical relationship of ventral foramen magnum and jugular foramen tumour is complex and the operation is very difficult. The aim of this study was to summarize the microsurgical experience of the removal of the ventral foramen magnum and jugular foramen tumours via the modified far lateral suboccipital approach assisted by three-dimensional computed tomography angiography (3D-CTA). Methods: The clinical data and follow-up results of 13 cases of 3D-CTA assisted suboccipital far lateral approach from July 2011 to September 2017 were analyzed retrospectively. There were 5 males and 8 females. Preoperative CT and MRI were used for routine imaging diagnosis, and the 3D-CTA simulated surgical approach was performed. The preoperative operation scheme was established, and the risk of operation was evaluated according simulated operation. After individualized exposure, the modified far lateral suboccipital approach was completed under the neuroelectrophysiological monitoring technique. Results: The preoperative images were completely consistent with the findings in the surgery. There were 9 cases of jugular foramen tumour and 4 cases of ventral foramen magnum tumour. Of the 13 cases, only 1 case of jugular glomus tumour had extra-cranial residual, while the whole intracranial tumour was removed. In other 12 cases, the tumours were completely removed under the microscope. After operation, the headache disappeared, and hearing loss was improved. There was no perioperative deaths, infection and cerebrospinal fluid leakage. The facial paralysis was occurred in 1 patient. After 3-39 months of follow-up, there was no recurrence of tumour, or new nerve function defect. Hoarseness, choking of drinking water and numbness of limbs were all improved at the end of the follow-up period. The symptoms of postoperative facial paralysis were also improved during the follow-up period. Conclusion: After the preoperative simulation and evaluation by 3D-CTA, the ventral foramen magnum and jugular foramen tumours can be rescted safely and effectively via far modified lateral suboccipital approach.\",\n \"Title: Augmented Time-Frequency Mask Estimation In Cluster-Based Source Separation Algorithms\\nYear: 2019\\n\\nAbstract: Time-frequency mask estimation with various clustering approaches has proven effective in solving the audio source separation problem. In this framework, the time-frequency bins of the mixture spectrogram are represented in a high-dimensional embedding space, where various methods can be applied to group the embedded points to calculate either hard or soft source assignments and subsequently the time-frequency masks. However, the mismatch between the assignment algorithm during the training and inference phases in majority of the current approaches leads to a suboptimal solution, because the assignment objective that is used during the training (e.g. ideal binary mask) is not the same as the one used during the inference phase (e.g. k-means clustering). We propose a method to reduce the mismatch between these two conditions where the source embedding is trained such that the source assignment during training and inference phases results in similar outcomes. Our results show that matching the source assignment during training-and inference-phase results in more accurate and consistent mask estimation in the inference phase which significantly improves the source separation accuracy for various hard and soft clustering methods.\",\n \"Title: Class-Specific Differential Detection In Diffractive Optical Neural Networks Improves Inference Accuracy\\nYear: 2019\\n\\nAbstract: Optical computing provides unique opportunities in terms of parallelization, scalability, power efficiency, and computational speed and has attracted major interest for machine learning. Diffractive deep neural networks have been introduced earlier as an optical machine learning framework that uses task-specific diffractive surfaces designed by deep learning to all-optically perform inference, achieving promising performance for object classification and imaging. We demonstrate systematic improvements in diffractive optical neural networks, based on a differential measurement technique that mitigates the strict nonnegativity constraint of light intensity. In this differential detection scheme, each class is assigned to a separate pair of detectors, behind a diffractive optical network, and the class inference is made by maximizing the normalized signal difference between the photodetector pairs. Using this differential detection scheme, involving 10 photodetector pairs behind 5 diffractive layers with a total of 0.2 million neurons, we numerically achieved blind testing accuracies of 98.54%, 90.54%, and 48.51% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively. Moreover, by utilizing the inherent parallelization capability of optical systems, we reduced the cross-talk and optical signal coupling between the positive and negative detectors of each class by dividing the optical path into two jointly trained diffractive neural networks that work in parallel. We further made use of this parallelization approach and divided individual classes in a target dataset among multiple jointly trained diffractive neural networks. Using this class-specific differential detection in jointly optimized diffractive neural networks that operate in parallel, our simulations achieved blind testing accuracies of 98.52%, 91.48%, and 50.82% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively, coming close to the performance of some of the earlier generations of all-electronic deep neural networks, e.g., LeNet, which achieves classification accuracies of 98.77%, 90.27%, and 55.21% corresponding to the same datasets, respectively. In addition to these jointly optimized diffractive neural networks, we also independently optimized multiple diffractive networks and utilized them in a way that is similar to ensemble methods practiced in machine learning; using 3 independently optimized differential diffractive neural networks that optically project their light onto a common output/detector plane, we numerically achieved blind testing accuracies of 98.59%, 91.06%, and 51.44% for MNIST, Fashion-MNIST, and grayscale CIFAR-10 datasets, respectively. Through these systematic advances in designing diffractive neural networks, the reported classification accuracies set the state of the art for all-optical neural network design. The presented framework might be useful to bring optical neural network-based low power solutions for various machine learning applications and help us design new computational cameras that are task-specific.\",\n \"Title: Conv-TasNet: Surpassing Ideal Time-Frequency Magnitude Masking for Speech Separation\\nYear: 2019\\n\\nAbstract: Single-channel, speaker-independent speech separation methods have recently seen great progress. However, the accuracy, latency, and computational cost of such methods remain insufficient. The majority of the previous methods have formulated the separation problem through the time–frequency representation of the mixed signal, which has several drawbacks, including the decoupling of the phase and magnitude of the signal, the suboptimality of time–frequency representation for speech separation, and the long latency in calculating the spectrograms. To address these shortcomings, we propose a fully convolutional time-domain audio separation network Conv-TasNet, a deep learning framework for end-to-end time-domain speech separation. Conv-TasNet uses a linear encoder to generate a representation of the speech waveform optimized for separating individual speakers. Speaker separation is achieved by applying a set of weighting functions masks to the encoder output. The modified encoder representations are then inverted back to the waveforms using a linear decoder. The masks are found using a temporal convolutional network consisting of stacked one-dimensional dilated convolutional blocks, which allows the network to model the long-term dependencies of the speech signal while maintaining a small model size. The proposed Conv-TasNet system significantly outperforms previous time–frequency masking methods in separating two- and three-speaker mixtures. Additionally, Conv-TasNet surpasses several ideal time–frequency magnitude masks in two-speaker speech separation as evaluated by both objective distortion measures and subjective quality assessment by human listeners. Finally, Conv-TasNet has a significantly smaller model size and a shorter minimum latency, making it a suitable solution for both offline and real-time speech separation applications. This study, therefore, represents a major step toward the realization of speech separation systems for real-world speech processing technologies.\",\n \"Title: ComQA: Question Answering over Knowledge Base via Semantic Matching\\nYear: 2019\\n\\nAbstract: Question answering over knowledge base (KBQA) is a powerful tool to extract answers from graph-like knowledge bases. Here, we present ComQA-a three-phase KBQA framework by which end-users can ask complex questions and get answers in a natural way. In ComQA, a complex question is decomposed into several triple patterns. Then, ComQA retrieves candidate subgraphs matching the triple patterns from the knowledge base and evaluates the semantic similarity between the subgraphs and the triple patterns to find the answer. It is a long-standing problem to evaluate the semantic similarity between the question and the heterogeneous subgraph containing the answer. To handle this problem, first, a semantic-based extension method is proposed to identify entities and relations in the question while considering the underlying knowledge base. The precision of identifying entities and relations determines the correctness of successive steps. Second, by exploiting the syntactic pattern in the question, ComQA constructs the query graphs for natural language questions so that it can filter out topology-mismatch subgraphs and narrow down the search space in knowledge bases. Finally, by incorporating the information from the underlying knowledge base, we fine-tune general word vectors, making them more specific to ranking possible answers in KBQA task. Extensive experiments over a series of QALD challenges confirm that the performance of ComQA is comparable to those state-of-the-art approaches with respect to precision, recall, and F1-score.\",\n \"Title: An Energy-Efficient Clustering Routing Protocol Based on a High-QoS Node Deployment with an Inter-Cluster Routing Mechanism in WSNs.\\nYear: 2019\\n\\nAbstract: Currently, wireless sensor network (WSN) protocols are mainly used to achieve low power consumption of the network, but there are few studies on the quality of services (QoS) of these networks. Coverage can be used as a measure of the WSN's QoS, which can further reflect the quality of data information. Additionally, the coverage requirements of regional monitoring target points are different in real applications. On this basis, this paper proposes an energy-efficient clustering routing protocol based on a high-QoS node deployment with an inter-cluster routing mechanism (EECRP-HQSND-ICRM) in WSNs. First, this paper proposes formula definitions for information integrity, validity, and redundancy from the coverage rate and introduces a node deployment strategy based on twofold coverage. Then, in order to satisfy the uniformity of the distribution of cluster heads (CHs), the monitoring area is divided into four small areas centered on the base station (BS), and the CHs are selected in the respective cells. Finally, combined with the practical application of the WSN, this paper optimizes the Dijkstra algorithm, including: (1) nonessential paths neglecting considerations, and (2) a simultaneous introduction of end-to-end weights and path weights, achieving the selection of optimal information transmission paths between the CHs. The simulation results show that, compared with the general node deployment strategies, the deployment strategy of the proposed protocol has higher information integrity and validity, as well as lower redundancy. Meanwhile, compared with some classic protocols, this protocol can greatly reduce and balance network energy consumption and extend the network lifetime.\",\n \"Title: Improved Alarm Visualization System Based on Two-Dimensional Online Root-cause Contribution Graph for Industry 4.0\\nYear: 2019\\n\\nAbstract: Process industry has entered a period of rapid development, and industrial safety is an eternal theme of industry 4.0. With the development of industry 4.0, the generation of a large amount of process data provides a research basis for process monitoring. The data-driven process monitoring algorithm sharply finds the abnormal value of the process by analyzing the data of normal condition. Different from the traditional alarm method and principal component analysis (PCA) contribution graph method, the Two-Dimensional Online Root-cause Contribution Graph (2D-ORCG) proposed in this paper is based on the traditional PCA method. Capturing information by the online root-cause variable visualization strategy proposed in this paper. Contribution analysis based on dynamic data can more effectively capture the key variables that affect the stability of the system, and also can accurately capture different variables at different times. Comparing to the traditional Two-Dimensional Contribution Graph method, the effectiveness of the 2D-ORCG method is demonstrated on the Tennessee Eastman Process (TEP).\",\n \"Title: Intelligent modeling using a novel feature extraction based multiple activation functions extreme learning machine\\nYear: 2019\\n\\nAbstract: For industry 4.0, intelligent modeling is very important. Modelling plays a very important role in making control strategies and production plans. Nevertheless, establishing an accurate and robust model becomes more difficult because of the increasing complexity of modelling data. To solve this problem, a novel feature extraction based multiple activation functions extreme learning machine (LV-MAFELM) is presented. The LV-MAFELM model is easy to construct: firstly, generate the input weights at random; secondly, select several different nonlinear activation functions and compute the hidden layer outputs; thirdly, extract principal components from the hidden layer outputs; finally, compute the output weights analytically. For verifying the model performance, the LV-MAFELM model is applied in one petrochemical industry process -the Purified Terephthalic Acid (PTA) process. Simulation results demonstrate that the presented LV-MAFELM achieves good performance, which indicates that accuracy and stability of energy prediction models can be improved.\",\n \"Title: Dual-Path Rnn For Long Recording Speech Separation\\nYear: 2021\\n\\nAbstract: Continuous speech separation (CSS) is an arising task in speech separation aiming at separating overlap-free targets from a long, partially-overlapped recording. A straightforward extension of previously proposed sentence-level separation models to this task is to segment the long recording into fixed-length blocks and perform separation on them independently. However, such simple extension does not fully address the cross-block dependencies and the separation performance may not be satisfactory. In this paper, we focus on how the block-level separation performance can be improved by exploring methods to utilize the cross-block information. Based on the recently proposed dual-path RNN (DPRNN) architecture, we investigate how DPRNN can help the block-level separation by the interleaved intra- and inter-block modules. Experiment results show that DPRNN is able to significantly outperform the baseline block-level model in both offline and block-online configurations under certain settings.\",\n \"Title: Ultra-wide Bandwidth Thin-film LiNbO3 Modulator with Record-Low Half-wave-voltage Length Product\\nYear: 2021\\n\\nAbstract: Novel electro-optic modulators are fabricated based on LiNbO3-silica hybrid waveguide and capacitively-loaded electrodes. Record-low half-wave-voltage length product of 1.7 V.cm and modulation bandwidth > 67 GHz are demonstrated. (C) 2021 The Author(s)\",\n \"Title: The heat exchange process between surface water and near-surface atmosphere in the front of the Three Gorges Dam\\nYear: 2021\\n\\nAbstract: •The Three Gorges Dam conceals the increase in air temperature.•The surface water temperature and air temperature have seasonal changes due to the dam.•The Three Gorges Dam affects the heat exchange of water-air interface.\",\n \"Title: Spatial Variations In Terrestrial Water Storage With Variable Forces Across The Yellow River Basin\\nYear: 2021\\n\\nAbstract: Terrestrial water storage (TWS) variations are a result of the interconnected impact of various variables including climate, hydrology, ecology, and anthropogenic activities. Previous studies have indicated that climate factors (e.g., precipitation and potential evapotranspiration), vegetation restoration, and water withdrawals (irrigational and industrial water use) are the major determinants of TWS depletion across the Yellow River Basin (YRB). However, few studies have provided explicit information about the main forcing variables that determine spatiotemporal variations in TWS and the synergies among these factors. This study explored the explicit understanding of hydro-climatic and socio-ecological determinants and the key interacting processes that affected the TWS variations across the Yellow River Basin in northern China. The multivariate adaptive regression splines model was employed to establish the relationship function of the long-term trends for the dependent (TWS) and independent (explanatory) variables consisting of normalized difference vegetation index (NDVI), hydro-climate, and human water withdrawal. The long-term trends estimated from the MARS model reproduced the ones calculated by Gravity Recovery and Climate Experiment gravity satellites, with a determination coefficient (R-2) of 0.83 and a mean absolute error (MAE) of 1.2 mm. The results showed that precipitation, minimum temperature, runoff, base flow, water withdrawal for electricity, and NDVI were the main drivers of the spatiotemporal variations in the TWS, of which minimum temperature and runoff played a considerable role in TWS variations through the interplay with other variables. The critical values of the trend for interactive variables, which could alter the acting direction of the synergy on the TWS, were also estimated. In view of the connotation of interactive variables, we suggested that spatiotemporal variations in TWS resulted from the coupling of the hydrological energy system, hydrological ecosystem, and hydrological system in the YRB, of which the hydrological system plays the most significant role, followed by the hydrological ecosystem.\",\n \"Title: Progressive anatomically constrained deep neural network for 3D deformable medical image registration\\nYear: 2021\\n\\nAbstract: The 3D deformable image registration is one of the most challenging tasks in medical image analysis. Due to the large and complex deformation in 3D medical images, many deep neural network based methods have been proposed to improve the image similarity after registration, among which recursive cascading network structure is one of the state-of-the-art. However, most existing works rely on the pixel-level image similarities to achieve anatomical rationality and overlook the global-level resemblance between the two structures. Therefore, the resulting registration is not quite clinically valuable. To this end, in this work, we propose a Progressive Anatomically Constrained deep neural Network (PACN) to incorporate the anatomical priors into a progressive cascading registration network to improve the anatomical plausibility as well as the pixel-level similarity of the registration results. Specifically, an Anatomical Constraint Encoder (ACE) network is proposed to encode the global context of the anatomical segmentations and attached to the dense registration network to form a registration unit. Repeated such units forming a cascading framework progressively warps the moving image toward the fixed one, with the output warped image of one unit as the input of the next unit. In this design, the global anatomical priors along with the pixel-level local information are used to guide the model learning process to produce high quality deformation field. Based on this, we explore two frameworks to investigate their registration effectiveness, one attaches the anatomical constraint encoder (ACE) to every dense registration sub-network and the other one attaches ACE only to the last dense registration unit. We test the two frameworks on benchmarks of three liver image datasets SLIVER, LiTS and LSPIG, and one brain dataset LPBA. Our two frameworks have achieved significantly better results in terms of average Dice score than the state-of-the-art baseline method on three liver datasets and comparable on LPBA when both tested with up to three cascades.\",\n \"Title: A cascaded registration network RCINet with segmentation mask\\nYear: 2021\\n\\nAbstract: Traditional deformable registration methods achieve brilliant results and show strong theoretical support but are computational intensive since they optimize each image pair's objective function. Recently, supervised learning methods have facilitated fast registration. However, it requires ground truth and does not guarantee a diffeomorphism registration. This paper proposes a new unsupervised learning method Recursive Cascaded Network with a segmentation mask, for two-dimensional medical image registration. Different from the original cascaded network, the network framework into two parts. The first section obtains a pair of image rolls and uses the registration sub-network to predict the deformation vector field from the moving image to the fixed image. The second part introduces anatomical segmentation into the network during training, makes full use of the auxiliary information of the volume, adds an autoencoder to encode the anatomical segmentation, and incorporates it into the learning process of the model in the form of constraints. The local and global ideas are combined to ensure the deformation field's rationality and improve the distribution. The most important thing is that we propose a formula for calculating the cascaded network's deformation field used in the test stage to evaluate the relationship between the registration accuracy and the deformation field's effectiveness. Our experiments show that the system has a better registration effect and less information loss than the current state-of-the-art method. Simultaneously, the cascade method's accuracy is an improvement at a certain number of layers, and the increase in accuracy needs to sacrifice the effectiveness of the deformation field.\",\n \"Title: From gratitude to injustice: Neurocomputational mechanisms of gratitude-induced injustice\\nYear: 2021\\n\\nAbstract: Gratitude shapes individuals’ behaviours and impacts the harmony of society. Many previous studies focused on its association with prosocial behaviours. A possibility that gratitude can lead to moral violation has been overlooked until recently. Nevertheless, the neurocognitive mechanisms of gratitude-induced moral violation are still unclear. On the other hand, though neural correlates of the gratitude's formation have been examined, the neural underpinnings of gratitude-induced behaviour remain unknown. For addressing these two overlapped research gaps, we developed novel tasks to investigate how participants who had received voluntary (Gratitude group) or involuntary help (Control group) punished their benefactors’ unfairness with functional magnetic resonance imaging (fMRI). The Gratitude group punished their benefactors less than the Control group. The self-report and computational modelling results demonstrated a crucial role of the boosted protection tendency on behalf of benefactors in the gratitude-induced injustice. The fMRI results showed that activities in the regions associated with mentalizing (temporoparietal junction) and reward processing (ventral medial prefrontal cortex) differed between the groups and were related to the gratitude-induced injustice. They suggest that grateful individuals concern for benefactors’ benefits, value chances to interact with benefactors, and refrain from action that perturbs relationship-building (i.e., exert less punishment on benefactors’ unfairness), which reveal a dark side of gratitude and enrich the gratitude theory (i.e., the find-bind-remind theory). Our findings provide psychological, computational, and neural accounts of the gratitude-induced behaviour and further the understanding of the nature of gratitude.\",\n \"Title: Hierarchical Authorization Of Convolutional Neural Networks For Multi-User\\nYear: 2021\\n\\nAbstract: Convolutional neural networks (CNNs) are widely used in many aspects and achieve excellent results. Due to the authorization from different users, we need to consider the right management caused by multi-user. This paper proposes a novel concept of hierarchical authorization of CNNs, and it can help owners control the output results according to accesses. To realize this idea, we refer to differential privacy and use the Laplace mechanism to perturb the output of the model to vary degrees. In experiments, we run on CIFAR-10 and MNIST datasets using ResNet and VGG, and the results show our method has significant grading effects.\",\n \"Title: Speech Separation Using an Asynchronous Fully Recurrent Convolutional Neural Network.\\nYear: 2021\\n\\nAbstract: Recent advances in the design of neural network architectures, in particular those specialized in modeling sequences, have provided significant improvements in speech separation performance. In this work, we propose to use a bio-inspired architecture called Fully Recurrent Convolutional Neural Network (FRCNN) to solve the separation task. This model contains bottom-up, top-down and lateral connections to fuse information processed at various time-scales represented by stages. In contrast to the traditional approach updating stages in parallel, we propose to first update the stages one by one in the bottom-up direction, then fuse information from adjacent stages simultaneously and finally fuse information from all stages to the bottom stage together. Experiments showed that this asynchronous updating scheme achieved significantly better results with much fewer parameters than the traditional synchronous updating scheme on speech separation. In addition, the proposed model achieved competitive or better results with high efficiency as compared to other state-of-the-art approaches on two benchmark datasets.\",\n \"Title: Computational anti-COVID-19 drug design: progress and challenges\\nYear: 2022\\n\\nAbstract: Vaccines have made gratifying progress in preventing the 2019 coronavirus disease (COVID-19) pandemic. However, the emergence of variants, especially the latest delta variant, has brought considerable challenges to human health. Hence, the development of robust therapeutic approaches, such as anti-COVID-19 drug design, could aid in managing the pandemic more efficiently. Some drug design strategies have been successfully applied during the COVID-19 pandemic to create and validate related lead drugs. The computational drug design methods used for COVID-19 can be roughly divided into (i) structure-based approaches and (ii) artificial intelligence (AI)-based approaches. Structure-based approaches investigate different molecular fragments and functional groups through lead drugs and apply relevant tools to produce antiviral drugs. AI-based approaches usually use end-to-end learning to explore a larger biochemical space to design antiviral drugs. This review provides an overview of the two design strategies of anti-COVID-19 drugs, the advantages and disadvantages of these strategies and discussions of future developments.\",\n \"Title: Data-Domain Traveltime Inversion of Reflected Waves Using Segment Dynamic Image Warping\\nYear: 2022\\n\\nAbstract: Reflection traveltime information is generally used for producing a kinematically accurate velocity model for seismic imaging. Accurately estimating the traveltime difference between the demigrated and observed data is crucial for data-domain reflection traveltime tomography. To enhance the robustness of signal's alignment, we propose a new method of segment dynamic image warping (SDIW). It first exploits windowed polynomial fitting for signal processing and then aligns the signals based on point-wise segment-to-segment matching. Compared with the conventional point-to-point matching strategy, our method is more robust and insensitive toward strong random noise. By minimizing the traveltime difference computed by SDIW, data-domain reflection traveltime inversion (DRTI) is then used to find an accurate background velocity model. Synthetic tests show that SDIW provides reliable time shifts between the demigrated and observed data even if the signal-to-noise ratio of input data is rather low. This enables DRTI to automatically reconstruct the deep background velocity model. The subsequent full waveform inversion (FWI) gradually added short-wavelength velocity structures and finally recovers a high-resolution and high-fidelity model. The results demonstrate that the DRTI provides a kinematically accurate background velocity model sufficient for following FWI to fully retrieve the detail of the subsurface structures even when the low frequencies are missing.\",\n \"Title: A multi-task graph convolutional network modeling of drug-drug interactions and synergistic efficacy\\nYear: 2021\\n\\nAbstract: Identification of drug-drug interaction(DDI) is critical for safer and more effective drug co-prescription. As wetlab screening assays are time-consuming, labor-intensive and expensive, it is highly desired to develop an effective computational method to predict drug-drug interactions. In this work, we aim to predict of drug-drug interactions and synergistic drug combinations by proposing an end-t...\",\n \"Title: GCNSDA: Predicting snoRNA-disease associations via graph convolutional network\\nYear: 2021\\n\\nAbstract: Small nucleolar RNAs(snoRNAs) represent an abundant group of noncoding RNAs in the nucleolus of eukaryotes. Recent studies revealed that snoRNAs play a significant role in a wide range of diseases. Identifying snoRNA-disease associations can provide great insights into understanding the disease and treatment and boosting drug discovery development. Traditional methods of using biological experimen...\",\n \"Title: ClawGAN: Claw connection-based generative adversarial networks for facial image translation in thermal to RGB visible light\\nYear: 2022\\n\\nAbstract: •ClawGAN for Thermal-Visible facial image translation is proposed.•We propose the Mismatch metric (MM) to measure mapping relationship of paired images.•We introduce the generative reconstructed loss and the synthesized loss to full objective.•The claw connection network architecture are used as the generator of GAN.\",\n \"Title: Node Representation Learning in Graph via Node-to-Neighbourhood Mutual Information Maximization\\nYear: 2022\\n\\nAbstract: The key towards learning informative node representations in graphs lies in how to gain contextual information from the neighbourhood. In this work, we present a simple-yet-effective self-supervised node representation learning strategy via directly maximizing the mutual information between the hidden representations of nodes and their neighbourhood, which can be theoretically justified by its link to graph smoothing. Following InfoNCE, our framework is optimized via a surrogate contrastive loss, where the positive selection underpins the quality and efficiency of rep-resentation learning. To this end, we propose a topology-aware positive sampling strategy, which samples positives from the neighbourhood by considering the structural dependencies between nodes and thus enables positive selection upfront. In the extreme case when only one positive is sampled, we fully avoid expensive neighbourhood aggregation. Our methods achieve promising performance on various node classification datasets. It is also worth mentioning by applying our loss function to MLP based node encoders, our methods can be orders of faster than existing solutions. Our codes and supplementary materials are available at https://github.com/dongwei156/n2n.\",\n \"Title: First Arrival Traveltime Picking Through 3-D U-Net\\nYear: 2022\\n\\nAbstract: In seismic exploration, picking first arrival traveltimes is an important step toward the estimation of subsurface velocity model, which has the direct impact on the well placement. In this letter, we present a 3-D deep learning method for automatic picking. In specific, we employ a supervised 3-D U-shaped full-convolutional network (3-D U-Net) to classify each sample in the 3-D seismic data into two categories: samples before and after the first break. Subsequently, we delineate a surface to separate these two categories, and such surface is corresponding to the desired first arrival traveltimes. In our training phase, besides the original normalized waveform data, we include the energy semblance feature as a channel of the input data, which helps to involve human understanding. The trained 3-D U-Net is applied to both synthetic and real datasets. The synthetic test shows that even if the labels contain some outliers, the predictions are still stable and reasonable in the sense that 3-D U-Net is capable of correcting some incorrect pickings. As for the field dataset test, the predicted results of 3-D U-Net are satisfactory based on human visual verification, and the picked traveltime surface is more consistent compared with the one predicted by the 2-D U-Net.\",\n \"Title: On the Use of Deep Mask Estimation Module for Neural Source Separation Systems\\nYear: 2022\\n\\nAbstract: Most of the recent neural source separation systems rely on a masking-based pipeline where a set of multiplicative masks are estimated from and applied to a signal representation of the input mixture. The estimation of such masks, in almost all network architectures, is done by a single layer followed by an optional nonlinear activation function. However, recent literatures have investigated the use of a deep mask estimation module and observed performance improvement compared to a shallow mask estimation module. In this paper, we analyze the role of such deeper mask estimation module by connecting it to a recently proposed unsupervised source separation method, and empirically show that the deep mask estimation module is an efficient approximation of the so-called overseparation-grouping paradigm with the conventional shallow mask estimation layers.\",\n \"Title: A 30-fps 192 × 192 CMOS Image Sensor With Per-Frame Spatial-Temporal Coded Exposure for Compressive Focal-Stack Depth Sensing\\nYear: 2022\\n\\nAbstract: In this article, we present a CMOS image sensor (CIS) for coded-exposure-based compressive focal-stack imaging. The proposed CIS has a pixel design, which includes two capacitive trans-impedance amplifiers (CTIAs) and a static random access memory (SRAM), and is capable of per-frame exposure encoding with adjustable spatiotemporal resolutions. A proof-of-concept CIS prototype with a 192 \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\times $ </tex-math></inline-formula>\\n 192 pixel array is designed and fabricated in a 0.13-\\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\mu \\\\text{m}$ </tex-math></inline-formula>\\n CMOS process with a pixel size of 12.6 \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\times $ </tex-math></inline-formula>\\n 12.6 \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"> <tex-math notation=\\\"LaTeX\\\">$\\\\mu \\\\text{m}^{2}$ </tex-math></inline-formula>\\n. Operating at 30 frames per second (fps), the CIS demonstrates spatial–temporal coded exposure at a maximum rate of 768 masks/frame. The column-wise 10-bit single-slope (SS) analog-to-digital converter (ADC) includes a ramp-slope adaptation feature used for power optimization. During a frame of coded exposure, a linear focal sweep is implemented by a voice-coil motor (VCM) lens mounted in front of the proposed CIS. Through the sparse reconstruction of the coded image, a focal stack consisting of a volume of defocused images is used to synthesize the scene depth map. By introducing coded exposure, the proposed on-chip compressive focal-stack imaging approach facilitates a frame-saving method for passive depth sensing in machine vision and other imaging applications.\",\n \"Title: A Highly Compact Thin-film Lithium Niobate Modulator with Low Half-wave Voltage\\nYear: 2022\\n\\nAbstract: Meandered thin-film lithium niobate modulators with capacitively loaded travelling-wave electrodes are demonstrated. Interdigitated T-rails are employed for reversed electric field, resulting in 1.08 V half-wave voltage and 3-dB bandwidth beyond 50 GHz for 8-mm-long devices. (C) 2022 The Author(s)\",\n \"Title: Evaluating the potential of H8/AHI geostationary observations for monitoring vegetation phenology over different ecosystem types in northern China\\nYear: 2022\\n\\nAbstract: •Different strategies for compositing daily EVI2 from 10-min AHI data were assessed.•Mean value compositing using data around solar noon minimized anisotropic effects.•Composited AHI daily EVI2 time series have 5.3 times more observations than MODIS.•Phenology dates were successfully retrieved from composited AHI EVI2 time series.•AHI can reduce uncertainty in phenology monitoring with more valid data and less gaps.\",\n \"Title: Review on the Change Trend, Attribution Analysis, Retrieval, Simulation, and Prediction of Lake Surface Water Temperature\\nYear: 2022\\n\\nAbstract: Lake surface water temperature (LSWT) is indicative of changes in climate and geomorphology. It has been found that LSWT has shown faster warming than air temperature in recent decades, which has greatly affected the aquatic ecosystem of lakes and even led to ecological collapse. It was mainly caused by climate warming and geomorphological changes caused by human activities. However, lakes with different properties respond differently to these changes, resulting in temporal and spatial heterogeneity in the changes of LSWT. After an extensive literature review, it was found that the research on LSWT is mainly focused on the following aspects: 1) qualitative or quantitative analysis of natural and anthropogenic factors affecting LSWT changes; 2) impacts of LSWT changes on lake ecology; 3) acquisition of LSWT data, such as retrieval based on remote sensing imagery, model-based simulation prediction; and 4) study of temporal and spatial variation characteristics of LSWT long time series. Dynamically monitoring LSWT changes, predicting, and quantifying the response of lakes with different properties to abrupt or gradual climate changes and changes in human activity intensity, can inform modeling of ecosystem response processes and long-term management planning of large freshwater ecosystems. Therefore, this article provides a systematic review of LSWT from the above four aspects to provide empirical insight and methodological reference for conducting LSWT research.\",\n \"Title: A Time-Domain Real-Valued Generalized Wiener Filter for Multi-Channel Neural Separation Systems\\nYear: 2022\\n\\nAbstract: Frequency-domain beamformers have been successful in a wide range of multi-channel neural separation systems in the past years. However, the operations in conventional frequency-domain beamformers are typically independently-defined and complex-valued, which result in two drawbacks: the former does not fully utilize the advantage of end-to-end optimization, and the latter may introduce numerical instability during the training phase. Motivated by the recent success in end-to-end neural separation systems, in this paper we propose time-domain real-valued generalized Wiener filter (TD-GWF), a linear filter defined on a 2-D learnable real-valued signal transform. TD-GWF splits the transformed representation into groups and performs an minimum mean-square error (MMSE) estimation on all available channels on each of the groups. We show how TD-GWF can be connected to conventional filter-and-sum beamformers when certain signal transform and the number of groups are specified. Moreover, given the recent success in the sequential neural beamforming frameworks, we show how TD-GWF can be applied in such frameworks to perform iterative beamforming and separation to obtain an overall performance gain. Comprehensive experiment results show that TD-GWF performs consistently better than conventional frequency-domain beamformers in the sequential neural beamforming pipeline with various neural network architectures, microphone array scenarios, and task configurations.\",\n \"Title: Simulation and Experimental Study on Vacuum Negative Pressure Infusion of Working Fluid for Micro Heat Pipes\\nYear: 2022\\n\\nAbstract: Optimum filling ratio as an important parameter has a great effect on the heat performance of heat pipes. Especially for micro heat pipes with only hundreds of microliters of internal volume, their optimum filling ratios are hard to be obtained without the filling accuracy of an order of microliter magnitude. This paper simulated the filling process of water as the working fluid, and the change regularities of the pressure, the velocity and the volume fraction of liquid water were investigated. The simulation results show that the flow pattern of plug flow is the key to leading to the infusion error. The liquid-vapor slugs caused the pulsation of pressure and velocity, which would make the flow flux uncontrollable accurately. The maximum relative error in simulated filling ratios reached -1.8%, of which -1.6% was due to the slug flows as against only 0.1% due to phase change. To eliminate the influence of slug flows formed under negative pressure, a novel charging method with a buffer pipeline was proposed. Then a test of five groups of different charging quantities (20 mu L, 25 mu L, 30 mu L, 40 mu L, and 50 mu L) for two MHPs with about 100 mu L internal volume was carried out, and the results suggest that the mean absolute error is below 1 mu L.\",\n \"Title: An AGV Positioning Algorithm for Reducing the Number of Reflectors\\nYear: 2022\\n\\nAbstract: Aiming at the problem of low global positioning precision and a large number of reflectors in the global feature map, an AGV positioning algorithm for reducing the number of reflectors is proposed. First, the global feature map is constructed by the reflectors. Next, the reflection points are obtained by lidar scanning, in which abnormal reflection points are removed through preprocessing. The local coordinates of the reflector are clustered and fitted by combining the reflection intensity of the reflector point. Then, the global coordinates of the reflectors are obtained by matching the local coordinates of the reflector with the global feature map. Finally, the initial position of the AGV is obtained through the static pose calculation algorithm, and the dynamic position of the AGV is solved by the two-point positioning algorithm. The experimental results show that, compared with the traditional algorithm, the positioning algorithm based on reflectors in this paper decreases the global position precision by 42.0% and 16.1% in the X-axis and Y-axis, respectively, and the number of reflectors used for the positioning algorithm is reduced from three or more to two.\",\n \"Title: Vegetation Productivity and Precipitation Use Efficiency across the Yellow River Basin: Spatial Patterns and Controls\\nYear: 2022\\n\\nAbstract: In arid and semi-arid climate zones, understanding the spatial patterns and biogeographical mechanisms of net primary production (NPP) and precipitation use efficiency (PUE) is crucial for assessing the function and stability of ecosystem services, as well as directing ecological restoration. Although the vegetation coverage has changed dramatically after the construction of several ecological restoration projects, due to limited observation data, fewer studies have provided a thorough understanding of NPP and PUE's recent spatial patterns and the controlling factors of different vegetation types in the Yellow River Basin (YRB). To narrow this gap, we integrated remote-sensing land-cover maps with long-term MODIS NPP and meteorological datasets to comprehend NPP and PUE spatial patterns in YRB. Furthermore, we applied structural equation models (SEM) to estimate the effect intensity of NPP and PUE controlling factors. The results showed that along geographical coordinates NPP and PUE decreased from southeast to northwest and trends were roughly consistent along latitude, longitude, and elevation gradients with segmented patterns of increasing and decreasing trends. As for climate gradients, NPP showed significant linear positive and negative trends across the mean annual precipitation (MAP) and the arid index (AI), while segmented changes for PUE. However, the mean annual average temperature (MAT) showed a positive slope for below zero temperature and no change above zero temperature for both NPP and PUE. SEM results suggested that AI determined the spatial pattern of NPP, whereas PUE was controlled by MAP and NPP. As the AI becomes higher in the further, vegetation tends to have decreased NPP with higher sensitivity to water availability. While artificial vegetation had a substantially lower NPP than original vegetation but increased water competition between the ecosystem and human society. Hence further optimization of artificial vegetation is needed to satisfy both ecological and economic needs. This study advanced our understanding of spatial patterns and biogeographic mechanisms of NPP and PUE at YRB, therefore giving theoretical guidance for ecological restoration and ecosystem function evaluation in the face of further climate change.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":163,"string":"163"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13361,"string":"13,361"}}},{"rowIdx":13362,"cells":{"question_id":{"kind":"string","value":"Masanori Sugimoto"},"question":{"kind":"string","value":"Generate an abstract for the title \"Vegetation interaction game: digital SUGOROKU of vegetation succession for children\" using the following items: sugoroku game, vegetation succession, elementary school, effective, joyful learning."},"answer":{"kind":"string","value":"In this study, we redesign and develop a new digital sugoroku game based on the phenomenon of vegetation succession. A practical evaluation in an elementary school that consisted of game play and fieldwork activity was conducted. The results of the evaluation showed that the game was effective in stimulating the interest of the students who participated in the game, and was able to support their learning in a joyful way."},"correct_answer":{"kind":"string","value":"In this study, we redesign and develop a new digital sugoroku game based on the phenomenon of vegetation succession. A practical evaluation in an elementary school that consisted of game play and fieldwork activity was conducted. The results of the evaluation showed that the game was effective in stimulating the interest of the students who participated in the game, and was able to support their learning in a joyful way."},"documents":{"kind":"list like","value":["Title: An Ultrasonic 3D Positioning System Using a Single Compact Receiver Unit\nYear: 2009\n\nAbstract: We present a system that can identify positions of objects in three-dimensional space using ultrasonic communications. The proposed system uses the time of flight of ultrasonic waves to calculate the distance between a transmitter and a microphone. An innovative method called the Phase Accordance Method is used for accurate detection of the arrival time of the ultrasonic signal for distance measurements. The main benefit of the proposed system is that it can locate positions of static and moving objects in a three-dimensional space by using only one compact receiver unit mounting three ultrasonic microphones; this will reduce the users' deployment tasks. Experimental results prove that the system possesses sufficient accuracy levels and stable performance of position measurements in static and dynamic situations, even though the beacon geometry of the system is poor.","Title: Caretta: a system for supporting face-to-face collaboration by integrating personal and shared spaces\nYear: 2004\n\nAbstract: In this paper, a system called Caretta that integrates personal and shared spaces to support face-to-face collaboration is described. We use PDAs and a multiple-input sensing board for personal and shared spaces, respectively. Users of Caretta can discuss and negotiate with each other in the shared space by manipulating physical objects, while they individually examine their ideas in their own personal spaces. Caretta allows users to participate in group activities interchangeably and seamlessly using both these spaces. Caretta is applicable to various collaborative tasks. In this paper, it supports users in urban planning tasks. User studies of Caretta demonstrated that it allowed users to collaborate in a flexible fashion: users could work individually in their personal spaces at their own pace, cooperatively work together in the shared space, and smoothly transition between both of the spaces.","Title: Skeleton growing: an algorithm to extract a curve skeleton from a pseudonormal vector field\nYear: 2013\n\nAbstract: A curve skeleton is used to represent a 3D object in many different applications. It is a 1D curve that captures topology of the 3D object. The proposed method extracts a curve skeleton from the vector field inside the 3D object. A vector at each voxel of the 3D object is calculated using a pseudonormal vector. By using such a calculation, the computation time is significantly reduced compared with using a typical potential field. A curve skeleton is then extracted from the pseudonormal vector field by using a skeleton-growing algorithm. The proposed algorithm uses high-curvature boundary voxels to search for a set of critical points and skeleton branches near high-curvature areas. The set of detected critical points is then used to grow a curve skeleton in the next step. All parameters of our algorithms are calculated from the 3D object itself, without user intervention. The effectiveness of our method is demonstrated in our experiments.","Title: VisiCon: a robot control interface for visualizing manipulation using a handheld projector\nYear: 2007\n\nAbstract: The miniaturization of image projectors leads to the expectation that projectors could be embedded in mobile devices such as cellular phones and PDAs. A projector mounted on a mobile device, freely movable in 3D space under user control, could operate not only as an output device but also as an input device for enabling humans to manipulate mobile robots. We therefore explore the possibilities of human-robot interaction techniques using handheld projectors. For this purpose, we propose an innovative interface called VisiCon. We have also developed a cooperative game, CoGAME, in which players guide a simple robot using handheld projectors. In this game, users can connect projected maps together, and cooperatively lead a robot to a specified goal. In this paper, we explain the techniques used in CoGAME, and present an evaluation.","Title: HybridTouch: an intuitive manipulation technique for PDAs using their front and rear surfaces\nYear: 2006\n\nAbstract: This paper describes a new manipulation technique for small-screen mobile devices. The proposed technique, called HybridTouch, uses a touchpad attached to the rear surface of a PDA. A user can manipulate the PDA by simultaneously touching the front surface with a stylus pen held by the dominant hand and the rear surface with a finger of the nondominant hand. User studies were conducted via applications augmented by HybridTouch, and proved that users could perform manipulation tasks intuitively.","Title: An immersive surface for 3D interactions\nYear: 2012\n\nAbstract: This paper proposes a new tabletop interface that enables a user to visualize projected objects as if they existed on the tabletop surface. It uses head tracking, without the need for any specialized head-mounted hardware, displays, or markers. Nowadays, many interactive tabletop interfaces support interactions above the surface because this is more intuitive. In these 3D interactions, users should be able to gauge the size and height of the projected virtual objects. We evaluate our system quantitatively via a 3D interaction task, by comparing it with a standard tabletop system.","Title: An accurate and compact 3D tracking system using a single camera and ultrasound\nYear: 2014\n\nAbstract: We propose a novel technique for 3D tracking that integrates a single camera and ultrasound. We use ultrasound with the Extended Phase Accordance Method to measure the distance accurately to a moving target and the camera for identifying the 2D position of the target on the image plane. A prototype system consists of a target unit mounting one ultrasound transmitter and three infrared LEDs surrounding it, and a receiver unit with one inexpensive camera and one ultrasound receiver. We implemented these units in a lightweight and compact way (receiver unit size: 55mm X 44 mm) to make the system robust to non-lineof-sight problems that frequently occur in trilateration or multicamera-based systems. To improve the ranging performance, we applied phase characteristic compensation of the ultrasound transducers by interpolating with a B-spline function and creating a compensated curved surface. Experimental results show that root-mean-square errors of the proposed system are 1.20mm and 1.66mm for static and mobile (target velocity: 1.0 m/s) settings, respectively. Thus, the performance of the system is comparable with that of high-end systems. Limitations of the proposed system and its possible applications are also discussed.","Title: CoGAME: manipulation using a handheld projector\nYear: 2007\n\nAbstract: An example of an application enhanced by the \"manipulation-by-projection\" technique, this cooperative game allows players to visually and intuitively control a robot with projectors. Players interchangeably move and connect their projected images to create a path that leads the robot to its goal.","Title: Design of an interactive system for group learning support\nYear: 2002\n\nAbstract: In this paper we describe our project to design a system that can be used as a teaching aid to support group learning in elementary school education. The system enhances the learning outcome for pupils who have studied environmental problems using a textbook, by allowing them to construct a town in a physical space and to assess the construction through computer simulations. The system was designed in collaboration with teachers and their pupils in elementary schools. Lessons learned from the collaborative design processes are described.","Title: A Dynamic Geometry Reconstruction Technique For Mobile Devices Using Adaptive Checkerboard Recognition And Epipolar Geometry\nYear: 2011\n\nAbstract: This paper describes a technique for reconstructing dynamic scene geometry using a handheld video projector-camera system and a single checkerboard image as a structured light pattern. The proposed technique automatically recognizes a dense checkerboard pattern under dynamic conditions. The pattern-recognition process is adaptive to different light conditions and an object's color, thereby avoiding the need to set threshold values manually for different objects when the scanning device is moving. We also propose a technique to find corresponding positions for the checkerboard pattern, when displayed by a projector, without needing any position-encoding techniques. The correspondence matching process is based on epipolar geometry, enabling the checkerboard pattern to be matched even if parts of it are occluded. By using a dense checkerboard pattern, we can construct a handheld projector-camera system that can acquire the geometry of objects in real time, and we have verified the feasibility of the proposed techniques.","Title: A system for supporting collaborative learning with networked sensing boards\nYear: 2004\n\nAbstract: The authors have used sensing boards based on RFID technology to construct a face-to-face group learning support system integrating the physical world and the virtual world. The system is shown to be useful through performance in that a learner without sufficient skill in using a computer can easily participate in learning, and knowledge acquired through textbooks and the like can be tested in the physical world. On the other hand, some problems have been pointed out: the utterances depend more strongly on the leader, and learning support with a higher degree of realism is desired. Consequently, in the system proposed in this paper, multiple sensing boards are placed at different sites so that the learner groups can communicate face-to-face. The sensing boards are connected through a network so that the operations on the board can influence each other. The learners in the group gather around the board and try to solve the problem face-to-face. They also interact with the learners in another group through a chat system. The learners in a primary school classroom used the system to study city design and environmental problems, and the effectiveness of the proposed system was demonstrated. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(9): 39–50, 2004; Published online in Wiley InterScience (). DOI 10.1002/scj.10502","Title: ipProjector: A Vision-Based Framework for Unsupervised Ubiquitous Object Augmentation Using a Portable Projector-Camera System\nYear: 2011\n\nAbstract: ipProjector stands for interactive portable projector which is a project trying to make a smart projection system while retaining absolute portability of the devices and setups. In this paper, an ipProjector framework is proposed for unsupervised real-time object augmentation applications. Scene-independent projector-camera geometric calibration is introduced so that the projected augmentation always appears in the desired geometry despite an unconstrained surface. Using nonintrusive projection, the system can ensure correct vision-based analysis because external appearances of the environment and object (as seen by the camera) are hardly changed by the overlaid projected content. Finally, an unsupervised visual detector is used to guarantee robustness of the detection regardless of lighting variations. Several image processing algorithms are applied in the framework, including image warping using perspective transformation, color conversion using the nearest-neighbor search algorithm, and multiscale visual detection. Based on a small-scale laboratory setting, experiments were conducted to evaluate the proposed approaches, and one example was built to prove the proposed concept in object augmentation.","Title: A storytelling support system using robots and handheld projectors\nYear: 2008\n\nAbstract: In this paper, a system called GENTORO that supports children's storytelling activities is proposed. By using GENTORO, children can make a robot play their story in the real world augmented with mobile projected graphical images. Preliminary user studies have been conducted in collaboration with elementary school children and university students, in order to investigate the acceptance level of GENTORO and clarify its design requirements, respectively. The development of GENTORO is in progress. The future plans of the GENTORO project are discussed.","Title: Clutter-aware adaptive projection inside a dynamic environment\nYear: 2008\n\nAbstract: This paper presents a framework for a computationally adaptive projection metaphor using a handheld projector inside a dynamic cluttered environment. In addition to conventional self-correcting projection features, the framework uses multiple clutter tracking and adaptive target generation to define the clutter-aware target area for projection in a reliable manner. Using a paired projector-camera system, the framework first builds high spatial frequency feature maps using a Laplacian pyramid approach. The feature maps are then passed to a rejection step to eliminate spurious features caused by contents of the projected image. After the resulting features representing clutters are processed by the appropriated design tracker, the target area for projection is generated. Finally, the desired information for projection is rendered and sent back to the projector. The framework can be used effectively for a clutter-aware handheld projector-based system without the need for a complex hardware setup or with any prior need to clean up the environment.","Title: An Outdoor Recommendation System based on User Location History\nYear: 2005\n\nAbstract: Recommendation systems are now widely used in online shopping sites, but so far there have been few attempts of applying them to real-world shopping. In this paper we propose a novel real-world recommendation system, which recommends shops to users based on their individual preferences and needs, estimated by analyzing their past location history acquired using GPS. The system automatically figures out each user's frequently visited shops using a custom estimation algorithm, and makes recommendations by using the shops as input to the item-based collaborative filtering algorithm. Furthermore, to provide more timely recommendations, our system takes into account the user's usual shopping routes, and the ease of access from the user's current location to each shop. We have conducted an evaluation test using a prototype of our system at Daikanyama, Tokyo, and the results show great promise in the system's ability to make accurate recommendations.","Title: Nurturing Learners' Communities By Creating And Sharing Maps\nYear: 2008\n\nAbstract: We present the SketchMap system, which integrates outdoor and classroom activities to support children's collaborative learning. Individual children create maps near their school in an outdoor environment using a SketchMap client. The maps are uploaded to the SketchMap web server for sharing among the children, who have created maps of different areas. Children can edit or add new information to the maps in their classroom or in their home. The goal of the SketchMap project is to investigate whether integrating outdoor and classroom activities, and sharing children's experiences through the maps can actually promote their collaborative learning and nurture learning communities including teachers and parents. The SketchMap system has been used in \"Safety Map\" and \"Nature Exploration\" classes in a Japanese elementary school. Evaluation of the SketchMap system is in progress, and issues found through the educational practices are described.","Title: A semi-automatic realtime calibration technique for a handheld projector\nYear: 2007\n\nAbstract: In this paper, a semi-automatic realtime calibration technique for a handheld projector is described. The proposed technique always keeps a shape of a projected screen rectangular on a specified projection surface, while a user continuously changes his standing position or the pose of the projector. The technique is especially useful for a future mobile phone with a built-in projector that allows a user to project its screen onto any surface in any location and share the screen with multiple people. Informal evaluations using the technique have been conducted to identify the level of its acceptability by users and to find problems to be improved. An example entertainment application to explore possibilities of the proposed technique has been developed.","Title: Symphony-Q: a support system for learning music through collaboration\nYear: 2002\n\nAbstract: This paper describes the Symphony-Q support system for learning music. This system integrates a sensing board and a computer, and is used for collaborative learning in a face-to-face setting. One of the aims of Symphony-Q is to enhance music experiences: children who do not have music skills can easily participate in music learning, enjoy making sounds, and play rhythmically to music in collaboration with others. The paper discusses comments and feedback from school children and their teachers, which were collected during experiments with Symphony-Q carried out in a Japanese public elementary school.","Title: RoboTable: an infrastructure for intuitive interaction with mobile robots in a mixed-reality environment\nYear: 2012\n\nAbstract: This paper presents the design, development, and testing of a tabletop interface called RoboTable, which is an infrastructure supporting intuitive interaction with both mobile robots and virtual components in a mixed-reality environment. With a flexible software toolkit and specifically developed robots, the platform enables various modes of interaction with mobile robots. Using this platform, prototype applications are developed for two different application domains: RoboPong investigates the efficiency of the RoboTable system in game applications, and ExploreRobot explores the possibility of using robots and intuitive interaction to enhance learning.","Title: Cooperative personal projection using multiple DLP projectors\nYear: 2011\n\nAbstract: In this poster, we propose a novel interaction concept called \"cooperative personal projection\", which relies mainly on the Digital Light Processing (DLP) color-wheel timing and short-exposure cameras. This concept combines recently popular single-projector personal-projection interactions with conventional multiprojector cooperative interactions, enabling several users to share their personal projections in a collaborative manner. By extending this proposed concept to multiexposure cameras and pro--cam coaxialization, we introduce a robust alternative for the real-time detection and identification of the geometry of overlapping projections in multiprojector scenarios that requires minimal computation.","Title: Development and Evaluation of a Digital Vegetation Interaction Game for Children\nYear: 2009\n\nAbstract: In this study, we develop a new digital sugoroku game that portray the phenomenon of vegetation succession in a forest. The results of the experimental evaluation showed that the game was effective in stimulating the interest of the students who participated in the game.","Title: Beyond binary choices: integrating individual and social creativity\nYear: 2005\n\nAbstract: The power of the unaided individual mind is highly overrated. Although society often thinks of creative individuals as working in isolation, intelligence and creativity result in large part from interaction and collaboration with other individuals. Much human creativity is social, arising from activities that take place in a context in which interaction with other people and the artifacts that embody collective knowledge are essential contributors.This paper examines: (1) how individual and social creativity can be integrated by means of proper collaboration models and tools supporting distributed cognition; (2) how the creation of shareable externalizations (\"boundary objects\") and the adoption of evolutionary process models in the construction of meta-design environments can enhance creativity and support spontaneous design activities (\"unselfconscious cultures of design\"); and (3) how a new design competence is emerging one that requires passage from individual creative actions to synergetic activities, from the reflective practitioner to reflective communities and from given tasks to personally meaningful activities. The paper offers examples in the context of collaborative design and art practice, including urban planning, interactive art and open source. In the effort to draw a viable path \"beyond binary choices\", the paper points out some major challenges for the next generation of socio-technical environments to further increase the integration of individual and social creativity.","Title: Toss-it: intuitive information transfer techniques for mobile devices\nYear: 2005\n\nAbstract: In recent years, mobile devices have rapidly penetrated into our daily lives. However, several drawbacks of mobile devices have been mentioned so far. The proposed system called Toss-It provides intuitive information transfer techniques for mobile devices, by fully utilizing their mobility. A user of Toss-It can send information from the user's PDA to other electronic devices with a toss or swing action, as the user would toss a ball or deal cards to others. This paper describes the current implementation of Toss-It and its user studies.","Title: Multicultural issues in the design, evaluation and dissemination of CSCL systems\nYear: 2002\n\nAbstract: This paper describes an overview of a panel that will be held as an interactive event in CSCL2002. Multicultural issues in design, evaluations and dissemination of CSCL systems are discussed. Four outstanding panelists will share their rich experiences, and propose how multicultural issues should be considered and examined in the context of system design and development and practice in school education, what problems should be dealt with, and how information technologies can contribute to promoting multicultural learning. Discussions are not limited to the panelists: active participation from the audience will be welcomed.","Title: A Robust Recognition Technique for Dense Checkerboard Patterns\nYear: 2010\n\nAbstract: The checkerboard pattern is widely used in computer vision techniques for camera calibration and simple geometry acquisition, both in practical use and research. However, most of the current techniques fail to recognize the checkerboard pattern under distorted, occluded or discontinuous conditions, especially when the checkerboard pattern is dense. This paper proposes a novel checkerboard recognition technique that is robust to noise, surface distortion or discontinuity, supporting checkerboard recognition in dynamic conditions for a wider range of applications. When the checkerboard pattern is used in a projector camera system for geometry reconstruction, by using epipolar geometry, this technique can recognize the corresponding positions of the crossing points, even if the checkerboard pattern is only partly detected.","Title: Novel interaction techniques based on a combination of hand and foot gestures in tabletop environments\nYear: 2012\n\nAbstract: Interactive tables, or tabletop devices, employ multi-finger gestures to interact with digital contents on a table's surface. Many studies have confirmed the convenience and intuitiveness of multi-finger gestures performed with the hands. However, there are still some tasks which cannot be conducted effectively by users via two-handed or multi-finger gestures. Given that feet are used occasionally in the real world to support the hands in the performance of complex tasks such as driving a car, we considered that it might be useful to combine foot gestures with hand gestures to enhance user interactions with tabletop environments. In this study, we developed a high-resolution foot sensing platform based on multi-touch techniques known as frustrated total internal reflection and diffused illumination. We then used the device to study the effect of combining hand and foot gestures on tabletop systems by using a 3D drawing application. We conducted user evaluations to compare foot gestures and identified which gestures were most comfortable for performing a 3D model rotation task. We also compared the performance in a 3D drawing task when using only hand gestures with the performance when using hand and foot gestures together. Finally, we discussed how hand and foot gesture combination techniques could provide new user experiences in tabletop environments.","Title: A system to visualize different viewpoints for supporting researchers' creativity\nYear: 1996\n\nAbstract: In this paper we describe a system to visualize different viewpoints for supporting researchers' creativity. The system has a text database composed of journal and conference papers. It elicits the viewpoints of the papers automatically and visualizes the semantic relations between them. By using it the users can find new viewpoints on their own research and form creative ideas. To evaluate the system, we carried out the user studies not only for creativity aid but also for communication aid and information retrieval, and confirmed its effectiveness.","Title: HATs: interact using height-adjustable tangibles in tabletop interfaces\nYear: 2011\n\nAbstract: We present Height-Adjustable Tangibles (HATs) for table-top interaction. HATs are active tangibles with 4 degrees of freedom that are capable of moving, rotating, and changing height. By adding height as an additional dimension for manipulation and representation, HATs offer more freedom to users than ordinary tangibles. HATs support bidirectional interaction, enabling them to reflect changes in the digital model via active visual feedback and to assist users via haptic feedback. A number of scenarios for using HATs are proposed, including interaction with complex and dependent models and applying HATs as tangible indicator widgets. We then introduce the implementation of HAT prototypes, for which we utilize motor-driven potentiometers to realize bidirectional interaction via the height dimension.","Title: Intuitive manipulation techniques for projected displays of mobile devices\nYear: 2005\n\nAbstract: Mobile devices (cellular phone, PDA, etc.) used by many people in their daily lives have so far been personal tools. Due to their multi-functionality, however, the devices have begun to be used by multiple people in co-located situations. This paper discusses near future technologies: a mobile device with a projector and intuitive manipulation techniques by using a video camera mounted on the device. It is difficult to realize a mobile device with a small and light projector that still retains the feature of mobility, so we have developed a system to project displays of mobile devices by tracking their three-dimensional positions and orientations. The proposed system called Hotaru (a firefly, in English) allows users to annotate, rotate or transfer files between multiple devices by touching their projected displays with fingers.","Title: CityVoyager: an outdoor recommendation system based on user location history\nYear: 2006\n\nAbstract: Recommendation systems, which automatically understand user preferences and make recommendations, are now widely used in online shopping. However, so far there have been few attempts of applying them to real-world shopping. In this paper, we propose a novel real-world recommendation system, which makes recommendations of shops based on users’ past location data history. The system uses a newly devised place learning algorithm, which can efficiently find users’ frequented places, complete with their proper names (e.g. “The Ueno Royal Museum”). Users’ frequented shops are used as input to the item-based collaborative filtering algorithm to make recommendations. In addition, we provide a method for further narrowing down shops based on prediction of user movement and geographical conditions of the city. We have evaluated our system at a popular shopping district inside Tokyo, and the results demonstrate the effectiveness of our overall approach.","Title: Mobile display-based manipulation: an intuitive and interactive technique for manipulating simple robots\nYear: 2008\n\nAbstract: In this paper, we propose the Mobile Display-based Manipulation (MDM) technique for manipulating simple robots such as automated cleaning robots. By capturing images of robots with a camera-attached mobile display and moving it in a three-dimensional space, a user can easily and intuitively manipulate the robots. To verify the validity and effects of the MDM technique, we developed two prototype systems using a handheld display and a projection display. Issues to be investigated and lessons learned through the design and evaluations of the systems are discussed.","Title: Evaluation Of Acoustic Imaging System Using Correlation Division In Synthetic Transmit Aperture With Multicarrier Signals\nYear: 2011\n\nAbstract: This paper presents and evaluates a new acoustic imaging system that uses multicarrier signals for correlation division in synthetic transmit aperture (CD-STA). CD-STA is a method that transmits uncorrelated signals from different transducers simultaneously to achieve highspeed and high-resolution acoustic imaging. In CD-STA, autocorrelations and cross-correlations in transmitted signals must be suppressed because they cause artifacts in the resulting images, which narrow the dynamic range as a consequence. To suppress the correlation noise, we had proposed to use multicarrier signals optimized by a genetic algorithm. Because the evaluation of our proposed method was very limited in the previous reports, we analyzed it more deeply in this paper. We optimized three pairs of multicarrier waveforms of various lengths, which correspond to 5th-, 6th-and 7th-order M-sequence signals, respectively. We built a CD-STA imaging system that operates in air. Using the system, we conducted imaging experiments to evaluate the image quality and resolution of the multicarrier signals. We also investigated the ability of the proposed method to resolve both positions and velocities of target scatterers. For that purpose, we carried out an experiment, in which both moving and fixed targets were visualized by our system. As a result of the experiments, we confirmed that the multicarrier signals have lower artifact levels, better axial resolution, and greater tolerance to velocity mismatch than M-sequence signals, particularly for short signals.","Title: Interactive and enjoyable interface in museum\nYear: 2005\n\nAbstract: Exhibitions at a scientific museum are usually difficult for ordinary school pupils. To improve the issues of current explanation systems, we use Personal Data Assistant (PDA) devices. Recent PDAs have enough functionality for people to interactively, individually, but it is not easy to assist that school pupils learn scientific knowledge merely using PDA.This research examined the main focus of the design and implementation of visual interfaces for PDAs for such a learning system. We aims the visual interface for PDAs have more interactive and entertainment to engage for learning scientific knowledge. Experiments using two prototype systems(Pi-book and Pit A Pat)implemented in the Flash/MX software toolkit have suggested the effectiveness on the performance and functionality of the proposed method.","Title: A Mobile Mixed-Reality Environment for Children's Storytelling Using a Handheld Projector and a Robot\nYear: 2011\n\nAbstract: This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. Pilot studies have been conducted to clarify the design requirements of GENTORO from both technological and practical viewpoints. A user study indicates that GENTORO's ability to enable manipulation of a robot using a handheld projector in a physical space can enhance children's embodied participation in, and their level of engagement with, their storytelling activities, and can support children in designing and expressing creative and original stories.","Title: Novel interaction techniques by combining hand and foot gestures on tabletop environments\nYear: 2011\n\nAbstract: Despite the convenience and intuitiveness of multi-touch gestures, there are some tasks that do not allow users to effectively conduct even using two-handed gestures. We propose novel input techniques of combining hand and foot gestures to enhance user interactions on tabletop environments. We have developed an early prototype of a sensor-based foot platform which recognizes subtle foot gestures, designed foot gestures and interactions which support simultaneous users' tasks and obtained their informal feedback.","Title: Multiscale Visual Object Detection for Unsupervised Ubiquitous Projection Based on a Portable Projector-Camera System\nYear: 2010\n\nAbstract: Ubiquitous projection is the recent effort that tries to close the gap between the physical world and the virtual world by using a mobile projector. Using a projector and camera together has a conflict of preferred light conditions, making it difficult to implement a robust visual detector while retaining ubiquity. In this paper, we focus on techniques of visual object detection for a portable projector-camera system. The goal is to create a visual detector that requires no guidance from a user and is robust to different light conditions. Our investigation involves the multiscale concept using Canny edge detection as a representative detector. Five image simplification filters applied to the multiscale detection are examined for both accuracy and speed. In addition, preprocessing using histogram equalization and post processing are applied to ensure robustness in a real-world scenario, and to guarantee that the detection will always successfully detect objects using a constant set of parameters defined offline. Finally, we showed that using multiscale detection in a parallel manner can speed up the detection while not affecting the accuracy of the detection.","Title: A novel template-based automatic rigging algorithm for articulated-character animation.\nYear: 2012\n\nAbstract: Rigging is a process for creating skeletons used to animate articulated characters. In conventional computer-animation software, this process must be performed manually. Although several automatic rigging algorithms have been proposed, these methods still require user intervention. This paper proposes an automatic algorithm that generates an inverse kinematic skeleton for a character by locating an appropriate template skeleton on the extracted curve skeleton of the input 3D character model. After the curve skeleton is extracted, it is analyzed and classified into an appropriate category. The classification conditions are developed from the characteristics of each kind of real animal. We also develop an algorithm to extract the anatomical meaning of each skeleton segment. On the basis of the classification result, a suitable template skeleton is retrieved from the database. Each bone of the template skeleton can then be located on the appropriate skeleton segment of the input skeleton graph by using the extracted anatomical meanings. In contrast to previous methods, the algorithm does not require the input 3D character models to have certain poses or orientations. Moreover, all processes can be completed without user intervention. Copyright (C) 2012 John Wiley & Sons, Ltd.","Title: A fully automatic rigging algorithm for 3D character animation\nYear: 2011\n\nAbstract: This paper proposes an automatic algorithm to generate an inverse kinematic (IK) skeleton for 3D characters. First, a curve skeleton is extracted from the volume inside the character mesh. The extracted curve skeleton is then analyzed and classified by comparing it with the characteristics of templates for real animals. The outcome of this classification step is an associated class for the given 3D character model, together with the meaning of each skeleton segment. Next, each bone of the template skeleton is located in the appropriate skeleton segment of the input skeleton graph. Unlike previous methods, this algorithm does not require an original 3D character model that is created with a restricted pose, topology and orientation. Furthermore, all stages of the process are completed without user intervention.","Title: TSaT-MUSIC: a novel algorithm for rapid and accurate ultrasonic 3D localization.\nYear: 2011\n\nAbstract: We describe a fast and accurate indoor localization technique using the multiple signal classification (MUSIC) algorithm. The MUSIC algorithm is known as a high-resolution method for estimating directions of arrival (DOAs) or propagation delays. A critical problem in using the MUSIC algorithm for localization is its computational complexity. Therefore, we devised a novel algorithm called Time Space additional Temporal-MUSIC, which can rapidly and simultaneously identify DOAs and delays of mul-ticarrier ultrasonic waves from transmitters. Computer simulations have proved that the computation time of the proposed algorithm is almost constant in spite of increasing numbers of incoming waves and is faster than that of existing methods based on the MUSIC algorithm. The robustness of the proposed algorithm is discussed through simulations. Experiments in real environments showed that the standard deviation of position estimations in 3D space is less than 10 mm, which is satisfactory for indoor localization.","Title: RoboTable: a tabletop framework for tangible interaction with robots in a mixed reality\nYear: 2009\n\nAbstract: Combining table top and tangible user interfaces is a relatively new research area. Many problems remain to be solved before users can benefit from tangible interactive table top systems. This paper presents our effort in this direction. RoboTable is an interactive table top system that enables users to naturally and intuitively manipulate robots. The goal of this research is to develop a software framework for human-robot interaction which combines table top, tangible objects, artificial intelligence and physics simulations and demonstrate the framework with game applications.","Title: Video summarization using personal photo libraries\nYear: 2006\n\nAbstract: In this paper, we propose a video summarization system which takes into account users' individual preferences by using their personal photo libraries. Nowadays it is common, especially among people of younger generations, to store thousands of photos inside their PCs and manage them using software such as iPhoto and Picasa. These personal photo libraries contain rich information about the user's tastes, personalities, and lifestyles. Since still photos are in many aspects similar to video as a medium, we assume that these personal photo libraries can be used to estimate users' preferences on video summarization.Our system first divides a movie into short segments, and uses image classification techniques to judge whether each segment is meaningful to the user or not. If many photos with contents similar to the segment can be found in the user's photo library, the segment is judged as being \"important\" to the user. Conventional image classification techniques use public or commercial photo databases as training data, while our system uses personal photo libraries. This difference leads to the need of several modifications in the classification process.We have implemented a prototype version of our system, and have validated the effectiveness of our approach through evaluating both the accuracy of our image classification algorithm, and users' subjective satisfaction levels of the summarization results.","Title: Electronically enhanced board games by integrating physical and virtual spaces\nYear: 2002\n\nAbstract: This paper describes an electronically enhanced board called E 2board. The motivation of our work comes from a traditional board game, which groups of players enjoy in a face-to-face situation by manipulating pieces on a physical board. In order to enhance users’ excitement and immersiveness, a physical board and a virtual world created by a computer are linked together with E 2board. An important function of E 2board is the rapid recognition of massive numbers of different objects. The authors have developed several applications using E 2board: not only games, but also systems for supporting group activities. Some of these applications are shown.","Title: Supporting children's rhythm learning using vibration devices\nYear: 2006\n\nAbstract: In this paper, a rhythm instruction tool for school children using vibration devices is discussed. The proposed system called T-RHYTHM is for supporting individual children in playing musical instruments or singing, in solo or ensemble situations. T-RHYTHM provides each child with rhythm patterns of musical pieces through tactile senses, and supports her so that she can recognize her own rhythm without being confused by other children's performances or singing voices. The rhythm of the music given to individual children is determined based on a performance by an accompanist and transmitted to their own vibration devices via a wireless communication. We have evaluated T-RHYTHM in a music class in a Japanese elementary school and gained initial feedback from children and their teacher.","Title: CarettaKids: a system for supporting children's face-to-face collaborative learning by integrating personal and shared spaces.\nYear: 2006\n\nAbstract: We developed a new system called CarettaKids that supports face-to-face collaborative learning by children. CarettaKids uses a sensing board based on the Radio Frequency Identification (RFID) technology to support collaboration in a shared space, and the Personal Digital Assistant (PDA) device to support activity in personal spaces. We also introduced this system into an actual classroom environment to evaluate its performance in support for children's collaborative learning, by analyzing the childrens' interaction. As a result, we have confirmed that CarettaKids's feature of transition between two spaces, makes it possible for children to reflect on problems detected in the shared space so as to find solutions in their respective personal space, and to engage in an active exchange of opinions in the shared space, based on ideas generated from personal-space learning.","Title: Development of a Full-Body Interaction Digital Game for Children to Learn Vegetation Succession\nYear: 2013\n\nAbstract: In this study, we developed a simulation game called \\\"Human SUGOROKU\\\" that simulates vegetation succession of the real forest area in the virtual world. This game consists of a full-body interaction system to enable children to enjoy and learn vegetation succession by playing with their body movement. We conducted an experiment with children and investigated the effects of the full-body interaction through interviews. The results showed that the full-body interaction promotes a sense of immersion in the game. This paper describes the structure of this system and the interview results.","Title: Fostering students' participation in face-to-face interactions and deepening their understanding by integrating personal and shared spaces\nYear: 2007\n\nAbstract: In this research, we introduced CarettaKids into the social context of a classroom environment to evaluate whether integration of personal and shared spaces can help promote students' participation in synchronous/co-located interactions in the classroom and deepen their understanding of subject matter. Analysis of videotaped interactions and pre-and posttests clarified the following three points. (1) Students who used CarettaKids presented the simulation results and rules for object arrangement they worked out individually in their respective personal space, by using CarettaKids' function of projecting object arrangements and simulation results from a personal digital assistant onto a sensing board. (2) Many of the students who used CarettaKids examined individually generated ideas collaboratively in the shared space. The patterns of collaborative examination are: (a) Induce a rule for object arrangement from object arrangements devised in personal spaces; (b) Deduce a new object arrangement from the rules discovered in the personal spaces; and (c) Refine the rules discovered in the personal spaces through group discussion. (3) Students who used CarettaKids not only considered all of the three factors, i.e. residential area, industrial area and forest area, but also understood relations between these factors, thereby deepening their understanding of city planning that takes environmental and financial aspects into consideration. We suggest that the degree to which students deepen their understanding is affected by the presence or absence of collaborative examination of individually generated ideas in the shared space.","Title: A Scalable Tracking System Using Ultrasonic Communication\nYear: 2009\n\nAbstract: Recently a new method of indoor ultrasonic localisation was introduced. It is called the Phase Accordance Method and the authors claim that with this technology they could measure the 2D coordinates of the transmitter by a single receiver and a single transmission of ultrasound. Also this method is reported to be able to locate static objects more accurately than conventional methods. In this paper we evaluated the ability of the method to locate moving objects. Experiments with a prototype system and a moving robot were conducted, which showed satisfying results. Issues to be investigated in the future work are described.","Title: Toss-It: Intuitive Information Transfer Techniques for Mobile Devices Using Toss and Swing Actions\nYear: 2006\n\nAbstract: Mobile devices have acceleratedly penetrated into our daily lives. Though they were originally designed as a communication tool or for personal use, and due to the rapid availability of wireless network technologies, people have begun to use mobile devices for supporting collaborative work and learning. There is, however, a serious problem in mobile devices related to their user interfaces. In this paper, we try to alleviate the problem and propose intuitive techniques for information transfer, which is one of the typical usages of mutually-connected computers. Our system, Toss-It, enables a user to send information from the user's PDA to other electronic devices with a \"toss\" or \"swing\" action, like a user would toss a ball or deal cards to others. The implementation of Toss-It consists of three principle parts - gesture recognition, location recognition, and file transfer. We especially describe the details of gesture recognition and location recognition. We then evaluate the practicability and usability of Toss-It through the experiments. We also discuss user scenarios describing how Toss-It can support users' collaborative activities.","Title: A correspondence matching technique of dense checkerboard pattern for one-shot geometry acquisition\nYear: 2010\n\nAbstract: This paper presents a correspondence matching technique for a dense checkerboard pattern displayed by a projector-camera system for one-shot geometry acquisition purposes. It does not require color coding or complicated spatial encoding techniques to encode the corresponding positions of corners, and can find corresponding positions for an incomplete checkerboard pattern. We introduce a combination of epipolar geometry and topology constraints in the checkerboard pattern to solve correspondence ambiguities. To verify the feasibility of the technique, we have created a prototype scanning system that can construct the 3D geometry of a scenario for each image frame. The results of our experiments show that the technique can identify correspondences for a checkerboard pattern displayed on discontinuous surfaces and can reconstruct 3D geometry structures in real time.","Title: A user-adaptive city guide system with an unobtrusive navigation interface\nYear: 2009\n\nAbstract: In this paper, we describe an intelligent location-aware city guide system, which adapts to each user's preferences, and uses an intuitive \"metal detector\" interface for navigation. Our system analyzes each user's past location data history to estimate individual preferences, and allows users to find shops that match their tastes in the same way a metal detector would be used to detect metal objects. The procedure with which the system picks out shops that match each user's preferences includes a newly developed place learning algorithm, which can efficiently find frequented places, complete with their proper names (e.g. \"The Ueno Royal Museum\"). We have conducted a series of evaluation tests at a popular shopping district inside Tokyo, and the results validate the effectiveness of our overall approach.","Title: User-adaptive home video summarization using personal photo libraries\nYear: 2007\n\nAbstract: In this paper, we propose a user-adaptive video summarization system which accounts for individual preferences by analyzing contents of the user's personal photo library. Nowadays, it is common practice for people to keep thousands of photos in their PCs, taken with their digital cameras. Due to the similarities in characteristics between video and still photos, we assume that these libraries can be used to infer each user's preferences on video summarization. The system uses image classification techniques to determine which sections of the movie are \"important\" to the user, and performs summarization by cutting off sections regarded as unimportant, while taking care not to overly disrupt the continuity of the video. We have implemented a prototype of the system, and conducted a series of evaluation tests to assess its effectiveness. The results show that our overall approach has the potential to serve as a powerful automatic/semi-automatic video summarization solution.","Title: Human SUGOROKU: learning support system of vegetation succession with full-body interaction interface\nYear: 2014\n\nAbstract: In this study, we developed a simulation game called \"Human SUGOROKU\" that consists of a full-body interaction system to enable elementary school students to enjoy and learn vegetation succession. The students' sense of immersion is improved by enabling them to play this game using their body movements. We conducted an experiment with the students and investigated the affects of the full-body interaction through questionnaires. The results showed that the full-body interaction promotes a sense of immersion in the game and enhance their understanding of vegetation succession. This paper describes the structure of this system and the questionnaires results.","Title: Supporting Self-Directed Learners and Learning Communities with Sociotechnical Environments\nYear: 2006\n\nAbstract: Making learning part of life is an essential challenge for inventing the future of our societies. Lifelong learning is a necessity rather than a possibility or a luxury to be considered. Self-directed learning (often occurring as learning on demand in response to breakdowns) is the dominant form of lifelong learning. The power of the unaided individual mind is highly overrated. Although society often thinks of creative individuals as working in isolation, learning and creativity result in large part from interaction and collaboration with other individuals. Much human creativity is social, and learning communities are needed to cope with the challenges of making learning part of life. This paper articulates existing problems in our current and future world requiring lifelong and self-directed learning and learning communities. It defines conceptual frameworks and it describes four innovative computational environments: (1) domain-oriented design environments , (2) critiquing systems, (3) the Envisionment and Discovery Collaboratory, and (4) Caretta). The paper concludes by providing a set of challenges for the future use of technology to enhance learning based on the conceptual frameworks and the experience and assessment of our system development efforts.","Title: A system for constructing private digital libraries through information space exploration\nYear: 1998\n\nAbstract: Digital libraries on the Internet are constructed separately and managed autonomously, and their semantics are different from each other. On the other hand, users of digital libraries have their own information needs. In order for users to fully utilize digital libraries, therefore, a new method for promoting mediation between the semantics of digital libraries and users' information needs is vital. COSPEX (COnceptual SPace EXplorer), proposed in this paper, is a system that can enhance such mediation. Through the exploration of information spaces encompassing multiple digital libraries, users of COSPEX can construct their own private digital libraries.","Title: T-RHYTHM: A System for Supporting Rhythm Learning by Using Tactile Devices\nYear: 2005\n\nAbstract: Individual, unaided human abilities are constrained. Media have helped us to transcend boundaries in thinking, working, learning, and collaborating by supporting distributed intelligence. Wireless and mobile technologies provide new opportunities for ...","Title: Human SUGOROKU: full-body interaction system for students to learn vegetation succession\nYear: 2013\n\nAbstract: In this study, we developed a simulation game called \"Human SUGOROKU\" that consists of a full-body interaction system to enable elementary school students to enjoy and learn vegetation succession. The students' sense of immersion is improved by enabling them to play this game using their body movements. We conducted an experiment with the students and investigated the affects of the full-body interaction through interviews. The results showed that the full-body interaction promotes a sense of immersion in the game. This paper describes the structure of this system and the interview results.","Title: Hotaru: intuitive manipulation techniques for projected displays of mobile devices\nYear: 2005\n\nAbstract: Mobile devices (cellular phone, PDA, etc.) have so far been personal tools. Due to their evolution to multi-functionality,\n however, the devices have begun to be used by multiple people in co-located situations. This paper discusses near future technologies:\n a mobile device with a projector and intuitive manipulation techniques by using a video camera mounted on the device. In today’s\n technologies, it is difficult to realize a mobile device with a small and lightweight projector that still retains the feature\n of mobility. Therefore, we have developed a system to project displays of mobile devices on a table, a floor, or a wall, by\n tracking their three-dimensional positions and orientations and using an existing LCD projector. The proposed system called\n Hotaru (a firefly, in English) allows users to annotate/rotate a picture or a document in a mobile device by touching its projected\n display with their fingers. Users can intuitively transfer a file between multiple devices by making their projected displays\n overlapped. Informal evaluations of Hotaru indicated that the proposed manipulation techniques could effectively support multiple people in co-located situations in\n conducting their tasks.","Title: Musex: A System for Supporting Children's Collaborative Learning in a Museum with PDAs\nYear: 2004\n\nAbstract: Using handheld devices in educational environments has begun to be recognized as suitable. Due to the drastic revisions in Japanese curriculum standards for elementary school children, new theories, systems and practices to support children in their learning are required. Therefore, we focused attention on science museums, which are different learning environments from schools. In this paper, we propose a system called Musex, which is used to support children in learning and exploring collaboratively in a museum with two PDAs (Personal Digital Assistants). Through Musex, children can collaboratively challenge some questions which are related to exhibitions. Solving the questions let children pay their attention to exhibitions naturally and understand contents of exhibitions more. We evaluated the system in a Japanese science museum and confirmed its effectiveness.","Title: Method to assist the building and expression of subjective concepts and its application to design problems\nYear: 1994\n\nAbstract: The paper discusses how computers can assist human creativity. A support system has been built and applied to the domain of automobile design. The system uses multidimensional data and statistical methods, and configures a space for inspiring the users' design activity. In the first step, it assists them in forming individual design concepts. In the second step, it assists them in deciding their target design concepts. It has been confirmed that it works effectively through experiments. Some of the open questions on creativity support systems are also discussed.","Title: Towards the Integration of Physical and Virtual Worlds for Supporting Group Learning\nYear: 2000\n\nAbstract: In this paper, we describe a system that integrates physical worlds (physical cities) and virtual worlds (digital cities), and its applications to supporting group learning. We have so far constructed several systems for supporting collaborative learning. One of the aims of CSCL (Computer-Supported Collaborative Learning) is to promote mutual learning through interactions and discussions among learners. Our previous experiments, however, have shown that these systems may not be so effective for supporting interactions and discussions at times. In order to enhance interactions further, a system should support externalization of each learner in an easily recognizable manner. Through such externalization, learners can actively collaborate or conflict with each other through discussions. The proposed system integrates a board game and a computer simulation, is used for studying urban planning and environmental problems. Each learner externalizes and represents his/her own ideas on a board game, which allows him/her to actively participate in a learning situation and to share the representations with other learners. The computer simulation calculates and visualizes the status of the city being constructed on the board game, in terms of air pollution, water pollution, etc.. Thirty fifth-grade pupils who had studied environmental problems in school participated in the experiments. The experiments showed that our system is effective for enhancing interactions, activating discussions, and raises learners' engagement.","Title: RoboTable2: a novel programming environment using physical robots on a tabletop platform\nYear: 2011\n\nAbstract: In this paper, we propose a novel environment called RoboTable2 that supports users with limited programming knowledge or experience in conducting robot programming. We have devised a tabletop platform that can simultaneously recognize multi-touch input and track physical robots, enabling users to conduct robot-programming tasks in an intuitive manner. A user study comparing the proposed and a conventional graphical programming environment was conducted, involving ten university students with no programming experience. The effects of the proposed environment were clarified via video analysis, questionnaires and usage logs. A pilot study was also conducted to verify how easily users could design and develop applications on RoboTable2. The lessons learned with respect to design guidelines for the proposed programming environment and issues for investigation are discussed.","Title: KIKIWAKE: sound source separation system for children-computer interaction\nYear: 2013\n\nAbstract: In general living environments, in order to separate children's voices from backgrounds noise, we developed a sound separation system by a microphone array. We created a game by use of this developed system, and conducted evaluation experiment intended for elementary school children. As a result, we confirmed this system could separate 3 voices, and the game promotes children's interest in or concerns about a microphone array in a quantitative way.","Title: Toward an Interactive Museum Guide System with Sensing and Wireless Network Technologies\nYear: 2002\n\nAbstract: In this paper, we describe an interactive guide system for kids in museums. The system uses a sensing board which can rapidly recognize types and locations of multiple objects, and creates an immersive environment by giving users visual and auditory feedback to their manipulations on the board. The purpose of the system is to attract users' interests in a real exhibition by allowing them to interact with the corresponding virtual exhibition on the board, and providing them with its information. We have evaluated the system in a museum. From the interviews and questionnaires, we have confirmed that it is easy for kids to use the system and it can raise their motivation for visiting real exhibitions.","Title: Skeleton-growing: a vector-field-based 3D curve-skeleton extraction algorithm\nYear: 2010\n\nAbstract: The vector-field-based method is one of the 3D curve-skeleton extraction algorithms. Typically, critical points in the vector field inside 3D objects are connected to form the curve-skeleton. However, critical points usually do not distribute to all important parts of the 3D object. Therefore, other features are used to produce a reliable result. Although this strategy can deliver a curve-skeleton that captures all of the important parts, the curve-skeleton usually comes with unnecessary segments. This paper proposes the skeleton-growing algorithm that automatically produces the curve-skeleton with small amounts of such segments. It searches for a set of high-curvature boundary voxels as starting points to find a set of suitable seed points that will be used to grow the curve-skeleton. We propose an unnecessary segment removal algorithm that can reduce the skeleton-noise density. A direction-selection algorithm is developed to avoid searching in irrelevant directions. The proposed method can produce a single reliable result curve-skeleton that could be applied in many different applications, including matching, animation, and visualization.","Title: Dual mode IR position and state transfer for tangible tabletops\nYear: 2011\n\nAbstract: This paper presents a method for tracking multiple active tangible devices on tabletops. Most tangible devices for tabletops use infrared to send information about their position, orientation, and state. The method we propose can be realized as a tabletop system using a low-cost camera to detect position and a low-cost infrared (IR) receiver to detect the state of each device. Since two different receivers (camera and IR-receiver) are used simultaneously we call the method dual mode. Using this method, it is possible to use devices with a large variation of states simultaneously on a tabletop, thus having more interactive devices on the surface.","Title: GENTORO: a system for supporting children's storytelling using handheld projectors and a robot\nYear: 2009\n\nAbstract: This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. A user study conducted in collaboration with elementary school children and teachers indicates that GENTORO's features can enhance children's embodied participation in, and their level of engagement with, their storytelling activities, and can support children in designing and expressing creative and original stories","Title: Novel interaction techniques using touch-sensitive tangibles in tabletop environments\nYear: 2012\n\nAbstract: In this work, we propose techniques for interaction that use a touch-sensitive tangible to assist 3D manipulation in tabletop applications. The objective of this research is to investigate the effectiveness and user satisfaction with this combination for performing virtual object manipulation in tabletop environments. A prototype of a touch-sensitive tangible was constructed and some of the proposed techniques were implemented, namely 3D translation and rotation. We conducted a pilot study to compare 3D manipulation on the tabletop with and without the tangible, from which we found that the touch-sensitive tangible was useful for 3D manipulation tasks.","Title: A system for supporting group learning that enhances interactions\nYear: 1999\n\nAbstract: In this paper, we describe and evaluate a system for supporting group learning that enhances interactions among learners. To date we have constructed several systems for supporting collaborative learning. One of the aims of CSCL is to promote mutual learning through interactions and discussions among learners. Our previous experiments, however, have shown that these systems may not be so effective for supporting interactions and discussions at times. In order to enhance interactions further, a system should support externalization of each learner in an easily recognizable manner. Through such externalization, learners can actively collaborate or conflict with each other through discussions.The proposed system integrates a board game and a computer simulation, and is used for studying urban planning and environmental problems. Each learner externalizes and represents his/her own ideas on a board game, which allows him/her to actively participate in a learning situation and to share the representations with other learners. The computer simulation helps the learners to understand the status of the town constructed on the board game.Several experiments were carried out in a public elementary school. The results show that our system is effective for enhancing interactions, discussions and learner engagement.","Title: A robust and dynamic scene geometry acquisition technique for a mobile projector-camera system\nYear: 2009\n\nAbstract: This paper presents a new structured light pattern generation technique, which allows acquisition of scene geometry from a single image, under various projection conditions with relatively high acquisition density. We construct the pattern by using the geometrical constraints of the projector-camera system, and solve the correspondence problem based on the local connectivity of the feature points and edges of the projection pattern. This method is robust from image processing perspective, and allows rapid geometry scanning using a mobile projector-camera system.","Title: What can Children Learn through Game-based Learning Systems?\nYear: 2007\n\nAbstract: In this talk, I will present key ideas and underlying philosophies of our research projects. I will also describe about several systems for supporting children's collaborative learning, such as CarettaKids, T-RHYTHM, and so on. Lessons learned through the design and e, aluation of these systems, and some thoughts for DIGITEL researches will be discussed.","Title: 3D FDM-PAM: rapid and precise indoor 3D localization using acoustic signal for smartphone\nYear: 2014\n\nAbstract: In this paper, we present an indoor 3D positioning method for smartphones using acoustic signals. In our proposed 3D Frequency Division Multiplexing--Phase Accordance Method (3D FDM--PAM), four speakers simultaneously emit burst signals comprising two carrier waves at different frequencies to enable the rapid calculation of the position of the smartphone. Through experiments, we show that 3D FDM--PAM can achieve a standard deviation of less than 2.8 cm at 7.8 measurements per second. The worst positioning error was 48.3 cm at the 95th percentile. We investigate the causes of error and discuss potential improvements to the localization performance.","Title: BESIDE: Body Experience and Sense of Immersion in Digital Paleontological Environment\nYear: 2015\n\nAbstract: We are developing an immersive learning support system for a paleontological environment within a museum. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first stage of this project, we have developed a prototype system that allows learners to experience the paleontological environment. Here, we evaluate the operability of the system, degree of learning support, and sense of immersion for primary schoolchildren. This paper summarizes the current system and describes the evaluation results.","Title: KIKIWAKE: participatory design of language play game for children to promote creative activitybased on recognition of japanese phonology\nYear: 2014\n\nAbstract: This study proposes a system for supporting the Shotoku Taishi game, which is a language play game that uses the voice of children. The Shotoku Taishi game is a group game in which multiple people presenting a problem vocalize different words at the same time and the respondents are required to guess what the combination of the words is. The authors developed and implemented a system using a microphone array to extract the voice of a specific person presenting a problem in this game. The participants were 36 elementary school students whose native language was Japanese. The results showed that the participants were enjoying the Shotoku Taishi game and that this group activity was a creative activity that deepened their awareness of the Japanese language.","Title: Smart Phone Localization Method Using Dual-Carrier Acoustic Waves\nYear: 2013\n\nAbstract: We describe an indoor localization technique for smart phones. Our new method, called the Frequency Division Multiplexing Phase Accordance Method (FDM-PAM), uses a beat called a sync pattern composed of a pair of sinusoidal waves with slightly different frequencies, which is similar to our original ultrasound ranging technique called the Phase Accordance Method (PAM). By generating multiple sync patterns with different central frequencies and transmitting them from different speakers, FDM-PAM conducts time-difference-of-arrival (TDOA) multilateration for localizing smart phones. In the current implementation of FDM-PAM, the 2D indoor position of a smart phone can be estimated. Three sync patterns are generated by using two out of six sinusoidal waves with frequencies ranging from 14.75 kHz to 17.25 kHz. The transmission of the sync pattern from the speakers lasts 4 ms. Through experiments, we have confirmed that FDM-PAM achieves accuracy of around 10 cm using only a short burst transmission, which indicates that the localization technique is sufficiently rapid and accurate.","Title: Discovering how other pupils think by collaborative learning in a classroom\nYear: 2000\n\nAbstract: The authors have so far developed a system that supports collaborative learning and evaluated it in school education. The system integrates physical and virtual worlds to teach urban planning and environmental problems by game playing by the pupils themselves. Intensive experiments with the system have proven that it can support the externalization of learners' thinking, active participation, interactions among them, and discussions in a learning situation. The paper addresses the effects of collaborative learning, and discusses how pupils discover the way of thinking of other pupils during game play","Title: Shepherd: An Interface for Overcoming Reference Frame Transformations in Robot Control\nYear: 2006\n\nAbstract: In this paper, we propose a system called Shepherd that allows a user to manipulate robots such as radio controlled cars from his viewpoint. The user of Shepherd can intuitively control the robots by capturing images of robots through a camera mounted on a mobile device, and moving it. User studies of Shepherd indicated that users could manipulate the robot in an intuitive manner.","Title: A Novel Framework for 3D Computer Animation Systems for Nonprofessional Users Using an Automatic Rigging Algorithm\nYear: 2012\n\nAbstract: This paper presents a novel framework for developing automatic animation systems, which accept a 3D model that is created at runtime. Previous systems cannot deal with such a 3D model because it needs to be prepared by a manual process (rigging) that may not be suitable for nonprofessional users. The proposed framework solves this problem by employing an automatic rigging algorithm. Our algorithm can generate an animation skeleton for a given 3D model automatically, including the anatomical meaning of each joint. The relationship between motion data and this animation skeleton is created by identifying the corresponding joints in the motion data and the skeleton. The motion data for each joint is transferred automatically to the 3D model that has been rigged via our automatic rigging algorithm. Because all processes can be completed without any user intervention, an animation system for nonprofessional users is therefore available. We also discuss several motion editing techniques that can be used to generate new motion data without complex processing.","Title: An intuitive computer animation system for enhancing human creativity\nYear: 2013\n\nAbstract: Computer animation can be used in a wide variety of applications, including storytelling. However, even producing low-quality computer animation requires a significant effort by professional users. Although it should be a tool capable of enhancing creativity in anyone, it is currently too difficult for some users. This paper presents a framework for a computer animation system that can reduce the difficulty of animation authoring, bringing such tasks within the reach of users at all levels. With this framework, users can focus on the story alone, rather than on details of the animation-creation method. The proposed system can therefore enhance users' creativity in story creation. The proposed framework comprises three modules, namely modeling, motion, and animation. Interaction with these modules is via simple actions, enabling computer animation to be created by anyone. A users' study is also presented in this paper to measure the performance of the proposed system in terms of ease of use and the capacity to enhance human creativity.","Title: A puppet interface for the development of an intuitive computer animation system\nYear: 2012\n\nAbstract: In this paper, we introduce a puppet interface for the development of an intuitive animation system. Our puppet interface does not require any special devices and any type of puppet can be used. The puppet interface is developed by attaching ten visible markers onto a puppet. The user can manipulate the pose of the puppet interface to produce the desired motion in front of a camera. The puppet's joint angle information is captured by the camera and used to retrieve a suitable motion from a motion database. The retrieved motion data is transferred to a 3D character model to generate an animation. To avoid the occlusion problem, we propose an algorithm that estimates the joint angle by determining the position and rotation of markers adjacent to the occluded marker. Experiments confirmed that our proposed algorithm can generate correct results, although some occluded markers remained.","Title: Using Image Features and Eye Tracking Device to Predict Human Emotions Towards Abstract Images.\nYear: 2015\n\nAbstract: Nowadays, emotional semantic image retrieval system enables users to access images that they want in a database according to emotional concept. This leads to affective image classification task which recently attracts researchers' attention. However, different users may experience different emotions depending on where, in the image, they are gazing on. This paper presents an improved prediction method by taking into account the users eye movement as implicit feedback while they are looking at the image. Our experimental results show that using both eye movement information and image feature together to determine users emotion gave more accurate predictions than using image feature alone.","Title: Light-Synchronized Acoustic Toa Measurement System For Mobile Smart Nodes\nYear: 2014\n\nAbstract: We describe a novel time-synchronization technique for mobile smart nodes. We capture modulated LED light with a video camera, which is usually built into a smart node. The CMOS image sensor of a video camera does not take a snapshot at a certain time. Instead, the sensor captures data on a line-by-line basis and the sensor output consists of lines taken at slightly different times. Therefore, we can extract time information from the image. This can be used for time synchronization for time-of-arrival (ToA) measurements. In this paper, we describe the fundamentals and an experiment using light-synchronized acoustic ToA measurements with mobile smart nodes. The acknowledged precision of the obtained time information is equivalent to 5.8 mm with an airborne sound wave.","Title: SyncSync: Time-of-arrival based localization method using light-synchronized acoustic waves for smartphones\nYear: 2015\n\nAbstract: In this paper we describe SyncSync, a novel time-of-arrival (ToA) localization method for smartphones. ToA measurements generally show better precision than time-difference-of-arrival measurements, but ToA systems require a synchronization mechanism between anchor and mobile nodes. For this synchronization, we employ modulated light with an acoustic signal for the time-of-flight distance measurement. These are detected by the smartphone's video camera and microphone. The time resolution in consumer video cameras is typically only a few tenths of a second, but by utilizing a CMOS image sensor's rolling shutter effect we obtain synchronization resolutions of a few microseconds, sufficient for precise acoustic ToA measurement. Experiments confirm operation of the system with localization errors within 10 mm.","Title: A rapid and accurate time-synchronization technique for acoustic localization using modulated illumination\nYear: 2015\n\nAbstract: This paper presents a rapid and accurate time-synchronization technique for acoustic localization. Two LED arrays for modulated illumination and an off-the-shelf camera are used. An equation that specifies the time difference between them accurately and precisely is proposed. Experiments in real environments show that the proposed technique using rectangular signals can achieve time synchronization to within 29.4 μs (5.94 μs standard deviation) and acoustic ranging to within 9.9 mm (2.01 mm standard deviation) for a measurement period of 0.1 s. Because of the smaller standard deviation in comparison with the error, it is indicated that there exist systematic errors to be removable. This technique will enable the implementation of an acoustic 3D localization system for mobile devices such as tablet PCs and smartphones based on time-of-arrival trilateration, which is more accurate than positioning taking a time-difference-of-arrival approach. Theoretical analyses for modulated illumination considering a camera exposure time clarify how an optimally modulated signal is designed for achieving rapid and accurate time synchronization.","Title: Toward a platform for collecting, mining, and utilizing behavior data for detecting students with depression risks\nYear: 2015\n\nAbstract: In this paper, we present our plan for constructing a platform for collecting, mining, and utilizing behavior data for detecting students with depression risks. Unipolar depression makes a large contribution to the burden of disease, being at the first place in middle- and high-income countries. We survey descriptors of depressions and then design a data collection platform in a classroom based on the assumption that such descriptors are also effective to students with depression risks. Visual, acoustic, and e-learning data are chosen for collection and various issues including devices, preprocessing, and consent agreements are investigated. We also show two kinds of utilization scenarios of the collected data and introduce several techniques and methods we developed for feature extraction and early detection.","Title: Science Education Enhancement within a Museum using Computer-human Interaction Technology.\nYear: 2016\n\nAbstract: We are developing an immersive learning support system for paleontological environments in museums. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first step toward realizing an immersive learning support system for museums, Yoshida et al. developed and evaluated a prototype system. However, their system cannot learn about certain paleontological features such as the names of extinct animals and their characteristics. Therefore, we developed an improved version of this system that allows for an enriched knowledge of paleontological environments, focusing in particular on extinct animals and plants and the ecological environment. Here, we evaluate the systemâs learning assistant and immersive features insofar as they are directed toward children in primary school. This paper summarizes the current system and describes the evaluation results.","Title: Reducing Redundancy With Unit Merging For Self-Constructive Normalized Gaussian Networks\nYear: 2016\n\nAbstract: In this paper, a Normalized Gaussian Network (NGnet) is introduced for online sequential learning that uses unit manipulation mechanisms to build the network model self-constructively. Several unit manipulation mechanisms have been proposed for online learning of an NGnet. However, unit redundancy still exists in the network model. We propose a merge mechanism for such redundant units, and change its overlap calculation in order to improve the identification accuracy of redundant units. The effectiveness of the proposed approach is demonstrated in a function approximation task with balanced and imbalanced data distributions. It succeeded in reducing the model complexity around 11% on average while keeping or even improving learning performance.","Title: Multiple-Player Full-Body Interaction Game to Enhance Young Children's Cooperation.\nYear: 2016\n\nAbstract: We have developed a full-body interaction game that allows children to cooperate and interact with other children in small groups. The aim of the game developed in this study is to encourage cooperation between children. The game requires two children to jump together at the same time. In a series of experiments, we observed children using several strategies to coordinate the timing of their jumps, such as shouting to one another and watching each other. The results of a questionnaire to evaluate the proposed interactive game indicate that children strategize to cooperate with each other while enjoying the game. Therefore, the game enables children to cooperate with others using bodily movements.","Title: Participatory Design of UKIYO-E Game for Children to Support Art Appreciation Based on Interacting with Pictures.\nYear: 2016\n\nAbstract: We are developing an art-appreciation system that will provide learning information about pictures while generating interest in the pictures themselves. This system can provide learning information on pictures by talking to an artist or people portrayed in the pictures using voice recognition. Furthermore, the system operates through movement and location of the user, and it generates sensation such that the user feels he/she is in the pictures, thus actively appreciating the pictures. As the first step toward this system, we have developed a system that provides learning information to the user by actively talking using ukiyo-e. Here, we quantitatively evaluate this system for primary schoolchildren and determine whether the user is interested in the pictures while talking to the pictures using voice recognition measured by electrodermal activity. In this paper, we summarize the current system and describe two evaluation results.","Title: Experience-based learning support system to enhance child learning in a museum: touching real fossils and \"experiencing\" paleontological environment.\nYear: 2015\n\nAbstract: This paper presents a support system to assist learning within museums. Museums represent important places of scientific learning for children. However, because the main learning method in museums is the study of displayed specimens and their corresponding explanations, the motivation of a child to learn is low. Hence, we are developing an experience-based learning support system such as entertainment that will enable learners to enhance their motivation to learn in any museum. We develop two systems to realize experience-based entertainment. One is \\\"Live Biblia,\\\" which is a digital installed book system that uses real fossil. Another is the immersive learning system we called \\\"Body Experience and Sense of Immersion in Digital paleontological Environment\\\" or \\\"BESIDE,\\\" which enables learners to explore a virtual paleontological environment. In this paper, we present a summary of the current system of Live Biblia and BESIDE.","Title: Optimally Modulated Illumination for Rapid and Accurate Time Synchronization.\nYear: 2017\n\nAbstract: This paper presents a rapid and accurate time-synchronization technique using an LED and an off-the-shelf camera. We discuss optimally modulated illumination as a function of camera exposure time through theoretical analysis and derive its mathematical representation. Experiments in real environments with a single LED and 60 fps camera show that the proposed technique can achieve time synchronization within a 17.4 $\\\\mu$ s error at the 90th percentile using only four frames (a measurement time of 0.067 s). Comparative experiments with computer simulations prove that the proposed technique using optimally modulated illumination to camera exposure time needs less CPU time than that using nonoptimally modulated illumination. The performance of the proposed technique derived from the noise distribution of intensities in captured images agrees closely with the experimental results, enabling time synchronization to be estimated within a confidence interval at a given confidence level. Possible applications to be developed by utilizing features of the proposed technique are described.","Title: Whisper to normal speech conversion using pitch estimated from spectrum.\nYear: 2016\n\nAbstract: A systematic method to connect a whispered vowel to its perceived pitch is presented.A regression function to predict the perceived pitch from the spectral information of the whispered speech is obtained.A whispered-to-normal speech converter is constructed and the pitch accents perceived in whispered Japanese words were recovered by the conversion. We can perceive pitch in whispered speech, although fundamental frequency (F0) does not exist physically or phonetically due to the lack of vocal-fold vibration. This study was carried out to determine how people generate such an unvoiced pitch. We conducted experiments in which speakers uttered five whispered Japanese vowels in accordance with the pitch of a guide pure tone. From the results, we derived a multiple regression function to convert the outputs of a mel-scaled filter bank of whispered speech into the perceived pitch value. Next, using this estimated pitch value as F0, we constructed a system for conversion of whispered speech to normal speech. Since the pitch varies with time according to the spectral shape, it was expected that the pitch accent would be kept by this conversion. Indeed, auditory experiments demonstrated that the correctly perceived rate of Japanese word accent was increased from 55.5% to 72.0% compared with that when a constant F0 was used.","Title: A spot-controllable data transfer technique using COTS speakers\nYear: 2016\n\nAbstract: This paper describes a spot-controllable data-transfer method. The proposed method generates a beam-shaped spot using two commercial off-the-shelf speakers. In our method, a symbol consists of a pair of sinusoidal waves having different angular frequencies. The width and direction of a beam-shaped spot are controlled by the angular-frequency difference between the sinusoidal waves and the transmission-time difference between the two speakers. Multiple spots can be generated by transmitting multiple pairs of sinusoidal waves based on the principle of orthogonal frequency-division multiplexing. By over-lapping multiple beam-shaped spots, the locations and sizes of the areas enabled to receive data are controllable. Experiments using four speakers and computer simulation show that the proposed method can generate controllable spots. An analysis of the errors in a real indoor environment indicate that they are caused by multipath signals, radiation damping of transmitted signals, and the incident/output angle characteristics of the microphone and speakers.","Title: Online EM for the Normalized Gaussian Network with Weight-Time-Dependent Updates.\nYear: 2016\n\nAbstract: In this paper, we propose a weight-time-dependent (WTD) update approach for an online EM algorithm applied to the Normalized Gaussian network (NGnet). WTD aims to improve a recently proposed weight-dependent (WD) update approach by Celaya and Agostini. First, we discuss the derivation of WD from an older time-dependent (TD) update approach. Then, we consider additional aspects to improve WD, and by including them we derive the new WTD approach from TD. The difference between WD and WTD is discussed, and some experiments are conducted to demonstrate the effectiveness of the proposed approach. WTD succeeds in improving the learning performance for a function approximation task with balanced and dynamic data distributions.","Title: Analytical Incremental Learning: Fast Constructive Learning Method for Neural Network.\nYear: 2016\n\nAbstract: Extreme learning machine ELM is a fast learning algorithm for single hidden layer feed-forward neural network SLFN based on random input weights which usually requires large number of hidden nodes. Recently, novel constructive and destructive parsimonious CP and DP-ELM which provide the effectiveness generalization and compact hidden nodes have been proposed. However, the performance might be unstable due to the randomization either in ordinary ELM or CP and DP-ELM. In this study, analytical incremental learning AIL algorithm is proposed in which all weights of neural network are calculated analytically without any randomization. The hidden nodes of AIL are incrementally generated based on residual error using least square LS method. The results show the effectiveness of AIL which has not only smallest number of hidden nodes and more stable but also good generalization than those of ELM, CP and DP-ELM based on seven benchmark data sets evaluation.","Title: Hinge Loss Projection for Classification.\nYear: 2016\n\nAbstract: Hinge loss is one-sided function which gives optimal solution than that of squared error SE loss function in case of classification. It allows data points which have a value greater than 1 and less than $$-1$$-1 for positive and negative classes, respectively. These have zero contribution to hinge function. However, in the most classification tasks, least square LS method such as ridge regression uses SE instead of hinge function. In this paper, a simple projection method is used to minimize hinge loss function through LS methods. We modify the ridge regression and its kernel based version i.e. kernel ridge regression so that it can adopt to hinge function instead of using SE in case of classification problem. The results show the effectiveness of hinge loss projection method especially on imbalanced data sets in terms of geometric mean GM.","Title: Integration Of Ultrasonic Sensors And Kinect Sensors For People Distinction And 3d Localization\nYear: 2013\n\nAbstract: The method proposed here for 3D position measurement and identification of individuals by integrating ultrasonic and Kinect sensors uses ultrasonic transmitter tags with unique identifiers. Ultrasonic sensors measure the 3D positions of and identify tagged individuals, but cannot make measurements if there are no receivers in the direction of ultrasonic waves from transmitters. Kinect sensors measure 3D positions of individuals and track them with OpenNI, but Kinect sensors cannot make measurements if occlusion occurs due to the overlapping of individuals. Evaluation results show that the method proposed here is more robust than methods only using either ultrasonic or Kinect sensors.","Title: Depth information based separation of moving speakers' voices from mixed recordings.\nYear: 2016\n\nAbstract: This paper proposes a method for separating the voice of a signal person from the voices of multiple speakersu0027 in a mixed recording. When the sounds of multiple speakers are present when a voice recognition system is operating, the quality of speech recognition decreases. The proposed method separates the sound of multiple speakers using signal processing techniques and a microphone array. The position of the speaker is also required; however, the microphone array cannot be used for this purpose. Consequently, the position of the speaker was determined using the Kinect V2 depth image sensor. An experiment was performed to separate a signal voice from many voices. The results of the experiment show that, it is possible to separate two voices using the proposed technique.","Title: Belong: Body Experienced Learning Support System Based On Gesture Recognition Enhancing The Sense Of Immersion In A Dinosaurian Environment\nYear: 2017\n\nAbstract: As the first step toward realizing an immersive learning support system for museums, Yoshida et al. developed and evaluated a prototype system. However, this system was problematic in that it could only be operated by using simple body movements. Moreover, the other problem was that learning about paleontology itself cannot be performed only by learning about a paleontological environment. Therefore, we developed an immersive learning support system \"BELONG\" as an upgraded version of the above-mentioned system. Using a recognizer capable of gesture recognition, the system can be operated using complicated body movements. The improved system enables learners to enhance their sense of immersion in a paleontological environment and learn about the fossil itself and its paleontology. This paper summarizes the prototype of \"BELONG\" and describes the experiments that were performed to evaluate its ability to achieve learning support and immersion.","Title: Development Of Experiential Learning System Based On The Connection Between Object Models And Their Digital Contents Collaboration Between Tangible Interface And Computer Interaction\nYear: 2017\n\nAbstract: Experiential learning is effective for educating children. However, there are many issues associated with this technique. In this study, we describe the development of a learning support system using which learners can experience touching and viewing in real and virtual environments. In the first stage of our study, we develop a larval mimesis experience system consisting of a Kinect sensor, larval models, and load sensors. The system is controlled using Arduino. Using the proposed system, learners can exercise full body interaction in the virtual environment; specifically, they can experience how larva models are observed in the real environment. The operation of this system was experimentally evaluated by learners from a primary school. The results indicate that the system is suitable for the use of children. In addition, the effectiveness of the learning support was evaluated by using a questionnaire. This paper summarizes the development of the proposed system and describes the evaluation results.","Title: Development Of Gesture Recognition Sub-System For Belong Increasing The Sense Of Immersion For Dinosaurian Environment Learning Support System\nYear: 2017\n\nAbstract: We are developing an immersive learning support system for paleontological environments in museums. The system measures the body movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment. Conventional systems are only able to recognize simple body movements, which is insufficient to completely immerse learners in the paleontological environment. On the other hand, when they need to perform complicated body movements, learners move their bodies eagerly while thinking. This emphasizes the importance of developing a sub-system capable of recognizing complicated body movements. In this paper, we describe a sub-system developed to recognize the body movement of the most important learner in the immersive learning support system.","Title: Satoyama: Time-Limited Decision Game For Students To Learn Hundreds Years Forestry Management\nYear: 2017\n\nAbstract: Global environmental problems continue to worsen. In this situation, it is important to understand and experience changes in the natural environment in realistic ways. However, it was difficult to experience these changes in real time because they happen over large time scales. To overcome this problem, the authors developed a game-like learning tool that enables players to learn about vegetation succession. This game is Windows-based and enables players to simulate the conservation of SATOYAMA, rural natural areas. The player selects the actions within a designated time and the vegetation succession of the SATOYAMA changes according to that action. At the end of this game, the score is based on the SATOYAMA conserved by the player. Thirty-seven students participated in this experiment whose result suggested that this game would enable children to develop an interest in vegetation succession and motivate them to learn about it.","Title: Laughing voice recognition using periodic waveforms and voice-likeness features.\nYear: 2016\n\nAbstract: With a goal of advancing human-machine collaboration, we propose a method to recognize a laughing voice. A previous study that proposed a laughing voice recognition method was based on the periodic waveform feature of the laughing voice. However, identifying laughing voices from waveforms is problematic, because this can result in false positive results. To overcome this problem, we propose a laughing voice recognition method that incorporates a voice-likeness feature. In addition, we make a laughing voice recognition system using our proposed method. To confirm the efficacy of the laughing voice recognition method, we evaluated this system. In our evaluation, we were able to correctly recognize laughing voice at a high success rate of 97%. In comparison with the previous study, the recognition rate improved by 18%; therefore, our proposed method can be considered an effective in recognizing laughing voice.","Title: Time-Of-Arrival-Based Indoor Smartphone Localization Using Light-Synchronized Acoustic Waves\nYear: 2017\n\nAbstract: We describe SyncSync, a time-of-arrival (ToA)-based localization method for smartphones. In general, ToA measurements show better precision than time-difference-of-arrival (TDoA) measurements, although ToA systems require a synchronization mechanism between anchor and mobile nodes. For this synchronization, we employ modulated LED light with an acoustic wave for time-of-flight distance measurements. These are detected by the smartphone's video camera and microphone. The time resolution in consumer video cameras is typically only a few tenths of a second, but by utilizing a CMOS image sensor's rolling shutter effect we obtain synchronization resolutions of a few microseconds, which is sufficient for precise acoustic ToA measurements. We conducted experiments to confirm operation of the system, and obtained ToA localization errors within 10 mm. The characteristics of the error distributions for both TDoA and ToA measurements were explained by dilution of precision.","Title: An Online Self-Constructive Normalized Gaussian Network With Localized Forgetting\nYear: 2017\n\nAbstract: In this paper, we introduce a self-constructive Normalized Gaussian Network (NGnet) for online learning tasks. In online tasks, data samples are received sequentially, and domain knowledge is often limited. Then, we need to employ learning methods to the NGnet that possess robust performance and dynamically select an accurate model size. We revise a previously proposed localized forgetting approach for the NGnet and adapt some unit manipulation mechanisms to it for dynamic model selection. The mechanisms are improved for more robustness in negative interference prone environments, and a new merge manipulation is considered to deal with model redundancies. The effectiveness of the proposed method is compared with the previous localized forgetting approach and an established learning method for the NGnet. Several experiments are conducted for a function approximation and chaotic time series forecasting task. The proposed approach possesses robust and favorable performance in different learning situations over all testbeds.","Title: OFDM Visible Light Communication using Off-the-shelf Video Camera\nYear: 2017\n\nAbstract: This paper describes a rapid and flicker-free visible light communication technique that uses an off-the-shelf video camera. Transfer rates at least 53% faster than existing methods were achieved in experiments. Features of the proposed method are discussed via theoretical analysis.","Title: Selective Visible Light Communication for Multiple Video Cameras using a Single Light Source.\nYear: 2018\n\nAbstract: In this paper, we propose a selective visible light communication method using a single light source and multiple video cameras by using their differences in reception sensitivity between carrier waves composed of OFDM signals. In our evaluation experiments, the transmitted signals were composed of 50th, 75th, 78th, and 80th order carrier waves encoding symbols modulated by 4, 8, and 16 PSK. The exposure time ratio for each camera was set to different values so that symbols encoded in one of the carrier waves could be decoded successfully, but erroneously in the other waves. The selectivity of individual carrier waves as theoretically derived was confirmed through the experimental results.","Title: Indoor Positioning Using Reflected Light and a Video Camera\nYear: 2018\n\nAbstract: This paper describes an indoor positioning technique using a video camera that captures LED light reflected by the floor. Indoor positioning for mobile devices can be very useful. In particular, localization techniques using LEDs and cameras, so-called visible light positioning, are known to be effective and have high accuracy. However, existing methods have the constraint that they must capture the light source directly. This requires a high-performance processor and a high-resolution image. However, light sources cannot always be detected directly (loss of signal: LOS). Our proposal aims to solve these problems by estimating the position of a camera that does not face the light directly but monitors light reflected by the floor. Specifically, individual LED ceiling lights emit sinusoidal waves modulated with different frequencies, and the camera captures the overlapped light from the LEDs reflected by the floor then demodulates the signal. The camera need not seek the ceiling lights directly from an image, unlike existing methods. The position can be estimated using any part of the image because usually the ceiling light is reflected by the whole floor. Experimental results show that the proposal requires less than 1/100 as many pixels for localization as existing methods and the position can be estimated within 0.4 m at the 90th percentile in a 2.5 m square room. We show that the cause of errors is mainly the difference between the LED diffusion model and the actual light diffusion, the occlusion and the noise and movement of the camera. Overcoming these problems remains as our future work.","Title: Smartphone Localization Using Active-Passive Acoustic Sensing\nYear: 2018\n\nAbstract: In this paper, we describe a novel position-recognition method that uses passive acoustic signals from two previously installed speakers (passive acoustic sensing) and active acoustic signals from a smartphone's loudspeakers (active acoustic sensing). In passive acoustic sensing, a locus of positions for the smartphone can be calculated from the measured time difference of arrival from the two installed speakers. In active acoustic sensing, a chirp signal is transmitted from the speakers of the smartphone, and the distance to the side wall is measured from the propagation time of arrival at its microphone. We can obtain the smartphone position from our proposed model equations by combining these two results. In our experiments, we installed speakers at intervals of 10 m along a corridor and estimated the smartphone position at several places. From these results, we obtained 90th percentile errors of less than 0.224 m for 2-D positioning. We found that multipaths from the side wall were causing the positioning error in passive acoustic sensing, and the variance of the positioning error using the top microphone which was omnidirectional was smaller than the bottom one. When we introduced a weighting based on the result of the active acoustic sensing and the difference in the performance between microphones, the 90th percentile errors were reduced to less than 0.134 m.","Title: Novel Application Of Spherical Microphone Array Sensor With Three-Dimensional Directivity For Home And Office Environments\nYear: 2015\n\nAbstract: Interest in sound interfaces is increasing because such interfaces do not need advanced knowledge about particular devices, nor do they require physical operation. However, such interfaces are difficult to use because the general living environment often contains background noise. In order to solve this problem, sound separation systems that use a microphone array sensor have been proposed. In previous work, this microphone array sensor was a small system that considered only two-dimensional (2-D) directivity control. In this paper, we present the design of a spherical microphone array sensor with 3D directivity. This 3-D directivity property is confirmed via an experimental evaluation.","Title: Novel application of a range image sensor to eye gaze estimation by using the relationship between face and eye directions\nYear: 2015\n\nAbstract: In this study, we estimate gaze direction using the relationship between the face and eyes. The face and eyes are divided laterally and in lengthwise direction. We set up an object laterally and in lengthwise direction and measured the face angle using a Kinect sensor, which is range image sensor, when gazing at an object. The angle of the eyes is fixed at the angle of the object and grasp of the relationship between face and eyes. We calculate the gaze direction using the relation between the face and eyes. Then, the results of present experiment, if based on relationship between face and eyes, has been shown to be effective though the results of the experiment.","Title: Electrodermal activity based study on the relationship between visual attention and eye blink\nYear: 2015\n\nAbstract: In this paper, the relationship between visual attention and eye blinking is described. In our experiment, we observed blinking when a subject performed a task. We determined that the subjectu0027s visual attention functions during the task by electrodermal activity. Experimental results showed that blink rate decreased when the subjectu0027s visual attention was engaged. On the other hand, blink rate increased when the subjectu0027s visual attention shifted from attentive to inattentive. These findings enable a more objective evaluation of the relationship between visual attention and blinking when determining by electrodermal activity whether visual attention is engaged.","Title: Novel application of Kinect sensor to support immersive learning within museum for children\nYear: 2015\n\nAbstract: This paper presents a system to support learning within museum for children as a novel application of Kinect based human sensing system. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first stage of this project, we have developed a prototype system that allows learners to experience the paleontological environment. Here, we evaluated the performance of the sensor of BESIDE in order to confirm whether or not this system can put into practice BESIDE at the museum. This paper summarizes the current system and describes the evaluation results.","Title: Poster: Multicamera Synchronization for Smartphones using Optimally Modulated Illuminations.\nYear: 2017\n\nAbstract: The paper describes a rapid and accurate time-synchronization technique for smartphones using their built-in cameras and its preliminary evaluations for application development.","Title: Novel application of 3D range image sensor for estimation of interests based on fixation time of face orientation\nYear: 2017\n\nAbstract: In this paper, we describe the relationship between the presence or absence of interest and the fixation time of face orientation. There is a conventional method of measuring the fixation time of line-of-sight orientation to prevent accidents due to carelessness. In addition, studies are being performed on the estimation of the relationship between face orientation and line-of-sight orientation. However, even if face and line-of-sight remain, it has not been confirmed whether people are interested. Therefore, we conducted experiments to investigate the relationship between the presence or absence of interest and the fixation time of face orientation. We simultaneously measured the change in interest and face orientation with time as subjects watched two movies. As a result, it was suggested that face orientation remained longer for an object of interest.","Title: Accuracy evaluation of hand motion measurement using 3D range image sensor\nYear: 2017\n\nAbstract: Techniques capable of measuring hand motion are expected to be applied in various situations. Examples are the practice support systems used in activities such as sport and dance, for instance, the system employed in baseball pitching form analysis. This analysis evaluates the state of the throwing form numerically and visually by measuring the velocity and trajectory of the hand. This requires measurement of the hand by a sensor and is accomplished by using a motion capture system as the method for measuring hand motion with high accuracy. However, it is time consuming to prepare the system. Therefore, a 3D range image sensor, which is inexpensive and easy to prepare, is proposed. However, as the actual measurement accuracy of this sensor is unknown, it was evaluated by calculating the error with the measured value of motion capture as the true value. In this research, we calculated the error between the 3D coordinates and velocity to evaluate the error. As a result, the effectiveness of the measurement accuracy of the hand motion by the 3D range image sensor was confirmed. The results suggest that the 3D range image sensor can be used in various situations involving human activity.","Title: Novel application of microphone array sensor for children's language learning support — Intelligent Interactive Design using voice separation and recognition system —\nYear: 2015\n\nAbstract: Development of a robust and precise voice interface could accelerate the realization of a learning support system that utilizes voice. In our research, this objective is called Intelligent Interactive Design of learning support. In order to realize Intelligent Interactive Design, we propose a “voice separation and recognition system” that aims at clear voice separation for robust voice recognition by voice recognition systems. The results of experiments conducted indicate that our Intelligent Interactive Design has a correct voice recognition rate above 70%. The results are highly satisfactory and indicate that Intelligent Interactive Design can be realized via our proposed system in the near future.","Title: EDA Sensor-based Evaluation of a Vegetation Succession Learning System\nYear: 2018\n\nAbstract: There are many forest problems that need to be solved to move toward a sustainable society; therefore, educating people, especially children, about forest problems is very important. Although schools conventionally educate children through textbooks, children are not expected to learn about forest problems actively from only textbooks. Therefore, this study develops game-type learning material that enables students learn complex mechanisms of vegetation succession and the actual state of succession, while taking interest in forest problems, by performing forest management themselves. For evaluation of the system, we measure the electrodermal activity (EDA) because using a conventional questionnaire can only qualitatively evaluate whether learning using the system is more interesting than when using text. EDA sensors are used to measure physiological response of participants reading texts and those using the system; the interest when using the system is evaluated quantitatively. The experiment shows that the change of EDA increases when using the system, which suggests that using the system is more interesting and can be better for learning than reading text.","Title: Detecting Text in Manga Using Stroke Width Transform\nYear: 2019\n\nAbstract: The Japanese comic-book style known as manga is becoming a popular topic for researchers. This paper focuses on the problem of detecting text regions in manga pages. Because it is time-consuming and laborious to identify the text regions in images manually, an automatic approach is highly desirable. Here, we propose a new text-detection method for manga using a Stroke Width Transform (SWT) technique in conjunction with a Support Vector Machine (SVM). Conventional SWT-based text-detection techniques perform poorly with manga because both text and non-text objects have similar characteristics for strokes, lines, and shapes. To better suit manga, we propose modifying the rules for finding letter candidates, which improves the ability to capture text. An SVM is then used to classify image patches into letter and nonletter regions. We compared our proposed framework with a conventional framework and other text-detection methods including deep-learning techniques. In the results, our proposed method achieved the highest F-measure of 0.506.","Title: Illegal Photograph Detection under Modulated LED Illumination\nYear: 2019\n\nAbstract: Nowadays, almost everyone has a smartphone and can easily take pictures. Consequently, illegal acts such as photographing or video-recording copyrighted works and uploading them to the internet are reported as a growing problem in our society. This paper proposes a method for detecting such illegal photography. By illuminating copyrighted works with an LED light emitting orthogonal frequency division multiplexing multi-carrier signals and utilizing the feature of exposure time ratio in a rolling shutter camera, it is possible to distinguish between photographs taken by authorized and unauthorized cameras. The evaluation experiments confirmed that the proposed method could correctly identify photographs taken by authorized and unauthorized cameras.","Title: Device-Free Handwritten Character Recognition Method Using Acoustic Signal\nYear: 2021\n\nAbstract: In this paper, we propose a method for recognizing handwritten characters by a finger using acoustic signals. This method is carried out using a smartphone placed on a flat surface, such as a desk. Specifically, this method uses an ultrasonic wave transmitted from the smartphone, which is reflected by the finger, and an audible sound is generated when writing a handwritten character. The proposed method does not require an additional device for handwritten character recognition because it uses the microphone/speaker built into the device. Evaluation results showed that it was able to recognize 36 types of characters with an average accuracy of 77.8% in a low noise environment for 10 subjects. In addition, it was verified that combining an audible sound and an ultrasonic wave in this method achieved higher recognition accuracy than when only an audible sound or an ultrasonic wave was used.","Title: Short-Time and Adaptive Controllable Spot Communication Using COTS Speaker\nYear: 2021\n\nAbstract: This paper proposes a spot-communication method that can direct the spot to the user location adaptively. In the proposed method, the first transmitted signals are used to estimate user location, which is then reflected in the second transmitted signals; therefore, the spot directed to the user can be generated instantaneously. As the signals consist of mutually orthogonal sinusoidal waves, multip...","Title: Indoor Localization Method For a Microphone Using a Single Speaker\nYear: 2021\n\nAbstract: In this paper, we propose a 2D localization method using a single speaker and a microphone. Our proposed method estimates the direction of the microphone based on the knowledge that the spectral amplitude of a speaker in each direction is different. Additionally, the distance between the speaker and microphone is estimated based on the received amplitude. The 2D location of the microphone is calcu...","Title: NL-Beep: A Ranging System between Multiple Smartphones Using Acoustic Sensing in NLOS Environments\nYear: 2021\n\nAbstract: In this paper, we describe NL-Beep, which is a novel ranging method between multiple smartphones using acoustic sensing in non-line-of-sight (NLOS) environments. We need to know the distance between people to maintain social distancing because of the COVID-19 pandemic. Acoustic-based ranging methods that use a smartphone built-in speaker and microphone represent one approach to high-accuracy rangi...","Title: Smartphone Positioning Using an Ambient Light Sensor and Reflected Visible Light\nYear: 2021\n\nAbstract: In this paper, we propose a method for the 2D positioning of a smartphone by receiving sinusoidally modulated light signals emitted by ceiling-mounted LEDs. An ambient light sensor (ALS) mounted on the smartphone measures the reflected illumination from the floor. The advantage of this combination is that it consumes very little power, does not require the implementation of additional devices, and...","Title: Expanding the Positioning Area for Acoustic Localization Using COTS Mobile Devices\nYear: 2021\n\nAbstract: In this paper, we propose a novel acoustic localization system using commercial off-the-shelf (COTS) mobile devices. Acoustic-based systems have advantages in terms of accuracy and cost. However, the measurable positioning area is limited because of the signal attenuation and the poor performance of microphones embedded in COTS mobile devices. Our system leverages a transmission scheme that combines time-division multiple-access (TDMA) and frequency-division multiple-access (FDMA) techniques to address the limitation. In the proposed approach, each speaker transmits different band chirps in a predefined sequence to mitigate multiple-access interference. A COTS device receives modulated signals via a built-in microphone. We exploit the received signals and estimate the position by calculating time difference of arrival (TDoA). We were able to reduce the error to a 90th-percentile error of 46.26 cm at a measurement point that could not be estimated by FDMA-based positioning. The experiment results show that our system is more accurate and has a larger area of positioning capability compared with FDMA-based positioning.","Title: A Localization Method Using Reflected Luminance Distribution\nYear: 2021\n\nAbstract: Visible light positioning is expected to become an effective means of indoor localization, but most existing methods require the capture of direct light, which is a significant limitation. In this paper, we propose a novel localization method based on received signal strength, which does not need to use direct light signals but instead uses reflected light from the floor. Our method is based on two observations. First, assuming a flat floor, the reflected light from the light source decays according to a gradient model whose peak is just below the light source. Second, the decay can be estimated effectively even for a floor surface several meters away from the light source. Inspired by these observations, we propose a method for estimating the coordinates of the floor surface and the two-dimensional coordinates of the light receiver (a camera). The method uses pattern matching within the distribution of signal decay measurements obtained via photographs of an arbitrary floor surface. Although the proposed method is vulnerable to shadow effects such as those caused by the camera tripod used in our experiments, we achieved a 90th percentile of less than 32 cm in our offline experiments. After removing the tripod shadows from the captured video manually, the same technique achieved a 90th percentile of 22 cm. To investigate the efficiency of the pattern matching, we also conducted experiments on the relationship between pixel utilization and localization results. In this paper, we also discuss camera posture estimation and power consumption issues.","Title: RefRec plus : Six Degree-of-Freedom Estimation for Smartphone Using Floor Reflecting Light\nYear: 2022\n\nAbstract: This paper describes a novel visible light positioning (VLP) system called RefRec+ allowing to estimate the six degree-of-freedom (6DoF) of a smartphone. In most existing VLP systems, their front camera faces multiple light sources installed at different places on a ceiling to detect their direct signals. To overcome the problem of the limited field of views that causes failure to capture required numbers of light sources for positioning and that of the high computational complexity because of image processing to a large-sized pixel data, RefRec+ captures indirect lights from the light sources reflected via a floor. RefRec+ estimates the 2-D position of a point of interest (POI) by calculating the received signal strength of individual light sources using the floor image captured by the camera. Using 2-D positions of multiple POIs and the angle of arrival method, RefRec+ obtains the 6DoF of the smartphone. Several experiments to confirm the performance of RefRec+ were conducted. Experimental results in a room measuring 4.0 m x 4.0 m using nine POIs each of which consists of 32 x 32 pixels in a captured image showed that the absolute errors at the 90th percentile for the 3-D coordinates were 0.2073 m, 0.1713 m, and 0.002464 m along the X, Y, and Z axes, respectively, and for the pitch, roll, and yaw angles were 5.78, 5.69 and 3.96 degrees, respectively.","Title: PT-Sync: COTS Speaker-based Pseudo Time Synchronization for Acoustic Indoor Positioning\nYear: 2022\n\nAbstract: Positioning with a small number of anchors is an important issue in the study of acoustic indoor positioning systems (AIPS). We present PT-Sync, a novel approach to time-synchronize between a commercial off-the-shelf (COTS) speaker and a mobile device by leveraging acoustic sensing and reflected signals from the floor. PT-Sync enables ranging with one speaker and 2-D positioning with two speakers without any additional hardware. Our proposed time synchronization method requires height information from the floor in the calculation process, which we estimate by active acoustic sensing. Using a unique averaging technique and IMU enables robust height estimation. PT-Sync can be used in a variety of indoor environments and can be time-synchronized with already installed speakers. The results of the evaluation experiment confirmed that a synchronization error of 0.16 ms was achieved even at a distance of 6 m from the speaker, and that synchronization on the order of microseconds could be achieved. Furthermore, pedestrian tracking experiments confirmed that positioning of less than 38.9 cm can be achieved at the 90th percentile."],"string":"[\n \"Title: An Ultrasonic 3D Positioning System Using a Single Compact Receiver Unit\\nYear: 2009\\n\\nAbstract: We present a system that can identify positions of objects in three-dimensional space using ultrasonic communications. The proposed system uses the time of flight of ultrasonic waves to calculate the distance between a transmitter and a microphone. An innovative method called the Phase Accordance Method is used for accurate detection of the arrival time of the ultrasonic signal for distance measurements. The main benefit of the proposed system is that it can locate positions of static and moving objects in a three-dimensional space by using only one compact receiver unit mounting three ultrasonic microphones; this will reduce the users' deployment tasks. Experimental results prove that the system possesses sufficient accuracy levels and stable performance of position measurements in static and dynamic situations, even though the beacon geometry of the system is poor.\",\n \"Title: Caretta: a system for supporting face-to-face collaboration by integrating personal and shared spaces\\nYear: 2004\\n\\nAbstract: In this paper, a system called Caretta that integrates personal and shared spaces to support face-to-face collaboration is described. We use PDAs and a multiple-input sensing board for personal and shared spaces, respectively. Users of Caretta can discuss and negotiate with each other in the shared space by manipulating physical objects, while they individually examine their ideas in their own personal spaces. Caretta allows users to participate in group activities interchangeably and seamlessly using both these spaces. Caretta is applicable to various collaborative tasks. In this paper, it supports users in urban planning tasks. User studies of Caretta demonstrated that it allowed users to collaborate in a flexible fashion: users could work individually in their personal spaces at their own pace, cooperatively work together in the shared space, and smoothly transition between both of the spaces.\",\n \"Title: Skeleton growing: an algorithm to extract a curve skeleton from a pseudonormal vector field\\nYear: 2013\\n\\nAbstract: A curve skeleton is used to represent a 3D object in many different applications. It is a 1D curve that captures topology of the 3D object. The proposed method extracts a curve skeleton from the vector field inside the 3D object. A vector at each voxel of the 3D object is calculated using a pseudonormal vector. By using such a calculation, the computation time is significantly reduced compared with using a typical potential field. A curve skeleton is then extracted from the pseudonormal vector field by using a skeleton-growing algorithm. The proposed algorithm uses high-curvature boundary voxels to search for a set of critical points and skeleton branches near high-curvature areas. The set of detected critical points is then used to grow a curve skeleton in the next step. All parameters of our algorithms are calculated from the 3D object itself, without user intervention. The effectiveness of our method is demonstrated in our experiments.\",\n \"Title: VisiCon: a robot control interface for visualizing manipulation using a handheld projector\\nYear: 2007\\n\\nAbstract: The miniaturization of image projectors leads to the expectation that projectors could be embedded in mobile devices such as cellular phones and PDAs. A projector mounted on a mobile device, freely movable in 3D space under user control, could operate not only as an output device but also as an input device for enabling humans to manipulate mobile robots. We therefore explore the possibilities of human-robot interaction techniques using handheld projectors. For this purpose, we propose an innovative interface called VisiCon. We have also developed a cooperative game, CoGAME, in which players guide a simple robot using handheld projectors. In this game, users can connect projected maps together, and cooperatively lead a robot to a specified goal. In this paper, we explain the techniques used in CoGAME, and present an evaluation.\",\n \"Title: HybridTouch: an intuitive manipulation technique for PDAs using their front and rear surfaces\\nYear: 2006\\n\\nAbstract: This paper describes a new manipulation technique for small-screen mobile devices. The proposed technique, called HybridTouch, uses a touchpad attached to the rear surface of a PDA. A user can manipulate the PDA by simultaneously touching the front surface with a stylus pen held by the dominant hand and the rear surface with a finger of the nondominant hand. User studies were conducted via applications augmented by HybridTouch, and proved that users could perform manipulation tasks intuitively.\",\n \"Title: An immersive surface for 3D interactions\\nYear: 2012\\n\\nAbstract: This paper proposes a new tabletop interface that enables a user to visualize projected objects as if they existed on the tabletop surface. It uses head tracking, without the need for any specialized head-mounted hardware, displays, or markers. Nowadays, many interactive tabletop interfaces support interactions above the surface because this is more intuitive. In these 3D interactions, users should be able to gauge the size and height of the projected virtual objects. We evaluate our system quantitatively via a 3D interaction task, by comparing it with a standard tabletop system.\",\n \"Title: An accurate and compact 3D tracking system using a single camera and ultrasound\\nYear: 2014\\n\\nAbstract: We propose a novel technique for 3D tracking that integrates a single camera and ultrasound. We use ultrasound with the Extended Phase Accordance Method to measure the distance accurately to a moving target and the camera for identifying the 2D position of the target on the image plane. A prototype system consists of a target unit mounting one ultrasound transmitter and three infrared LEDs surrounding it, and a receiver unit with one inexpensive camera and one ultrasound receiver. We implemented these units in a lightweight and compact way (receiver unit size: 55mm X 44 mm) to make the system robust to non-lineof-sight problems that frequently occur in trilateration or multicamera-based systems. To improve the ranging performance, we applied phase characteristic compensation of the ultrasound transducers by interpolating with a B-spline function and creating a compensated curved surface. Experimental results show that root-mean-square errors of the proposed system are 1.20mm and 1.66mm for static and mobile (target velocity: 1.0 m/s) settings, respectively. Thus, the performance of the system is comparable with that of high-end systems. Limitations of the proposed system and its possible applications are also discussed.\",\n \"Title: CoGAME: manipulation using a handheld projector\\nYear: 2007\\n\\nAbstract: An example of an application enhanced by the \\\"manipulation-by-projection\\\" technique, this cooperative game allows players to visually and intuitively control a robot with projectors. Players interchangeably move and connect their projected images to create a path that leads the robot to its goal.\",\n \"Title: Design of an interactive system for group learning support\\nYear: 2002\\n\\nAbstract: In this paper we describe our project to design a system that can be used as a teaching aid to support group learning in elementary school education. The system enhances the learning outcome for pupils who have studied environmental problems using a textbook, by allowing them to construct a town in a physical space and to assess the construction through computer simulations. The system was designed in collaboration with teachers and their pupils in elementary schools. Lessons learned from the collaborative design processes are described.\",\n \"Title: A Dynamic Geometry Reconstruction Technique For Mobile Devices Using Adaptive Checkerboard Recognition And Epipolar Geometry\\nYear: 2011\\n\\nAbstract: This paper describes a technique for reconstructing dynamic scene geometry using a handheld video projector-camera system and a single checkerboard image as a structured light pattern. The proposed technique automatically recognizes a dense checkerboard pattern under dynamic conditions. The pattern-recognition process is adaptive to different light conditions and an object's color, thereby avoiding the need to set threshold values manually for different objects when the scanning device is moving. We also propose a technique to find corresponding positions for the checkerboard pattern, when displayed by a projector, without needing any position-encoding techniques. The correspondence matching process is based on epipolar geometry, enabling the checkerboard pattern to be matched even if parts of it are occluded. By using a dense checkerboard pattern, we can construct a handheld projector-camera system that can acquire the geometry of objects in real time, and we have verified the feasibility of the proposed techniques.\",\n \"Title: A system for supporting collaborative learning with networked sensing boards\\nYear: 2004\\n\\nAbstract: The authors have used sensing boards based on RFID technology to construct a face-to-face group learning support system integrating the physical world and the virtual world. The system is shown to be useful through performance in that a learner without sufficient skill in using a computer can easily participate in learning, and knowledge acquired through textbooks and the like can be tested in the physical world. On the other hand, some problems have been pointed out: the utterances depend more strongly on the leader, and learning support with a higher degree of realism is desired. Consequently, in the system proposed in this paper, multiple sensing boards are placed at different sites so that the learner groups can communicate face-to-face. The sensing boards are connected through a network so that the operations on the board can influence each other. The learners in the group gather around the board and try to solve the problem face-to-face. They also interact with the learners in another group through a chat system. The learners in a primary school classroom used the system to study city design and environmental problems, and the effectiveness of the proposed system was demonstrated. © 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(9): 39–50, 2004; Published online in Wiley InterScience (). DOI 10.1002/scj.10502\",\n \"Title: ipProjector: A Vision-Based Framework for Unsupervised Ubiquitous Object Augmentation Using a Portable Projector-Camera System\\nYear: 2011\\n\\nAbstract: ipProjector stands for interactive portable projector which is a project trying to make a smart projection system while retaining absolute portability of the devices and setups. In this paper, an ipProjector framework is proposed for unsupervised real-time object augmentation applications. Scene-independent projector-camera geometric calibration is introduced so that the projected augmentation always appears in the desired geometry despite an unconstrained surface. Using nonintrusive projection, the system can ensure correct vision-based analysis because external appearances of the environment and object (as seen by the camera) are hardly changed by the overlaid projected content. Finally, an unsupervised visual detector is used to guarantee robustness of the detection regardless of lighting variations. Several image processing algorithms are applied in the framework, including image warping using perspective transformation, color conversion using the nearest-neighbor search algorithm, and multiscale visual detection. Based on a small-scale laboratory setting, experiments were conducted to evaluate the proposed approaches, and one example was built to prove the proposed concept in object augmentation.\",\n \"Title: A storytelling support system using robots and handheld projectors\\nYear: 2008\\n\\nAbstract: In this paper, a system called GENTORO that supports children's storytelling activities is proposed. By using GENTORO, children can make a robot play their story in the real world augmented with mobile projected graphical images. Preliminary user studies have been conducted in collaboration with elementary school children and university students, in order to investigate the acceptance level of GENTORO and clarify its design requirements, respectively. The development of GENTORO is in progress. The future plans of the GENTORO project are discussed.\",\n \"Title: Clutter-aware adaptive projection inside a dynamic environment\\nYear: 2008\\n\\nAbstract: This paper presents a framework for a computationally adaptive projection metaphor using a handheld projector inside a dynamic cluttered environment. In addition to conventional self-correcting projection features, the framework uses multiple clutter tracking and adaptive target generation to define the clutter-aware target area for projection in a reliable manner. Using a paired projector-camera system, the framework first builds high spatial frequency feature maps using a Laplacian pyramid approach. The feature maps are then passed to a rejection step to eliminate spurious features caused by contents of the projected image. After the resulting features representing clutters are processed by the appropriated design tracker, the target area for projection is generated. Finally, the desired information for projection is rendered and sent back to the projector. The framework can be used effectively for a clutter-aware handheld projector-based system without the need for a complex hardware setup or with any prior need to clean up the environment.\",\n \"Title: An Outdoor Recommendation System based on User Location History\\nYear: 2005\\n\\nAbstract: Recommendation systems are now widely used in online shopping sites, but so far there have been few attempts of applying them to real-world shopping. In this paper we propose a novel real-world recommendation system, which recommends shops to users based on their individual preferences and needs, estimated by analyzing their past location history acquired using GPS. The system automatically figures out each user's frequently visited shops using a custom estimation algorithm, and makes recommendations by using the shops as input to the item-based collaborative filtering algorithm. Furthermore, to provide more timely recommendations, our system takes into account the user's usual shopping routes, and the ease of access from the user's current location to each shop. We have conducted an evaluation test using a prototype of our system at Daikanyama, Tokyo, and the results show great promise in the system's ability to make accurate recommendations.\",\n \"Title: Nurturing Learners' Communities By Creating And Sharing Maps\\nYear: 2008\\n\\nAbstract: We present the SketchMap system, which integrates outdoor and classroom activities to support children's collaborative learning. Individual children create maps near their school in an outdoor environment using a SketchMap client. The maps are uploaded to the SketchMap web server for sharing among the children, who have created maps of different areas. Children can edit or add new information to the maps in their classroom or in their home. The goal of the SketchMap project is to investigate whether integrating outdoor and classroom activities, and sharing children's experiences through the maps can actually promote their collaborative learning and nurture learning communities including teachers and parents. The SketchMap system has been used in \\\"Safety Map\\\" and \\\"Nature Exploration\\\" classes in a Japanese elementary school. Evaluation of the SketchMap system is in progress, and issues found through the educational practices are described.\",\n \"Title: A semi-automatic realtime calibration technique for a handheld projector\\nYear: 2007\\n\\nAbstract: In this paper, a semi-automatic realtime calibration technique for a handheld projector is described. The proposed technique always keeps a shape of a projected screen rectangular on a specified projection surface, while a user continuously changes his standing position or the pose of the projector. The technique is especially useful for a future mobile phone with a built-in projector that allows a user to project its screen onto any surface in any location and share the screen with multiple people. Informal evaluations using the technique have been conducted to identify the level of its acceptability by users and to find problems to be improved. An example entertainment application to explore possibilities of the proposed technique has been developed.\",\n \"Title: Symphony-Q: a support system for learning music through collaboration\\nYear: 2002\\n\\nAbstract: This paper describes the Symphony-Q support system for learning music. This system integrates a sensing board and a computer, and is used for collaborative learning in a face-to-face setting. One of the aims of Symphony-Q is to enhance music experiences: children who do not have music skills can easily participate in music learning, enjoy making sounds, and play rhythmically to music in collaboration with others. The paper discusses comments and feedback from school children and their teachers, which were collected during experiments with Symphony-Q carried out in a Japanese public elementary school.\",\n \"Title: RoboTable: an infrastructure for intuitive interaction with mobile robots in a mixed-reality environment\\nYear: 2012\\n\\nAbstract: This paper presents the design, development, and testing of a tabletop interface called RoboTable, which is an infrastructure supporting intuitive interaction with both mobile robots and virtual components in a mixed-reality environment. With a flexible software toolkit and specifically developed robots, the platform enables various modes of interaction with mobile robots. Using this platform, prototype applications are developed for two different application domains: RoboPong investigates the efficiency of the RoboTable system in game applications, and ExploreRobot explores the possibility of using robots and intuitive interaction to enhance learning.\",\n \"Title: Cooperative personal projection using multiple DLP projectors\\nYear: 2011\\n\\nAbstract: In this poster, we propose a novel interaction concept called \\\"cooperative personal projection\\\", which relies mainly on the Digital Light Processing (DLP) color-wheel timing and short-exposure cameras. This concept combines recently popular single-projector personal-projection interactions with conventional multiprojector cooperative interactions, enabling several users to share their personal projections in a collaborative manner. By extending this proposed concept to multiexposure cameras and pro--cam coaxialization, we introduce a robust alternative for the real-time detection and identification of the geometry of overlapping projections in multiprojector scenarios that requires minimal computation.\",\n \"Title: Development and Evaluation of a Digital Vegetation Interaction Game for Children\\nYear: 2009\\n\\nAbstract: In this study, we develop a new digital sugoroku game that portray the phenomenon of vegetation succession in a forest. The results of the experimental evaluation showed that the game was effective in stimulating the interest of the students who participated in the game.\",\n \"Title: Beyond binary choices: integrating individual and social creativity\\nYear: 2005\\n\\nAbstract: The power of the unaided individual mind is highly overrated. Although society often thinks of creative individuals as working in isolation, intelligence and creativity result in large part from interaction and collaboration with other individuals. Much human creativity is social, arising from activities that take place in a context in which interaction with other people and the artifacts that embody collective knowledge are essential contributors.This paper examines: (1) how individual and social creativity can be integrated by means of proper collaboration models and tools supporting distributed cognition; (2) how the creation of shareable externalizations (\\\"boundary objects\\\") and the adoption of evolutionary process models in the construction of meta-design environments can enhance creativity and support spontaneous design activities (\\\"unselfconscious cultures of design\\\"); and (3) how a new design competence is emerging one that requires passage from individual creative actions to synergetic activities, from the reflective practitioner to reflective communities and from given tasks to personally meaningful activities. The paper offers examples in the context of collaborative design and art practice, including urban planning, interactive art and open source. In the effort to draw a viable path \\\"beyond binary choices\\\", the paper points out some major challenges for the next generation of socio-technical environments to further increase the integration of individual and social creativity.\",\n \"Title: Toss-it: intuitive information transfer techniques for mobile devices\\nYear: 2005\\n\\nAbstract: In recent years, mobile devices have rapidly penetrated into our daily lives. However, several drawbacks of mobile devices have been mentioned so far. The proposed system called Toss-It provides intuitive information transfer techniques for mobile devices, by fully utilizing their mobility. A user of Toss-It can send information from the user's PDA to other electronic devices with a toss or swing action, as the user would toss a ball or deal cards to others. This paper describes the current implementation of Toss-It and its user studies.\",\n \"Title: Multicultural issues in the design, evaluation and dissemination of CSCL systems\\nYear: 2002\\n\\nAbstract: This paper describes an overview of a panel that will be held as an interactive event in CSCL2002. Multicultural issues in design, evaluations and dissemination of CSCL systems are discussed. Four outstanding panelists will share their rich experiences, and propose how multicultural issues should be considered and examined in the context of system design and development and practice in school education, what problems should be dealt with, and how information technologies can contribute to promoting multicultural learning. Discussions are not limited to the panelists: active participation from the audience will be welcomed.\",\n \"Title: A Robust Recognition Technique for Dense Checkerboard Patterns\\nYear: 2010\\n\\nAbstract: The checkerboard pattern is widely used in computer vision techniques for camera calibration and simple geometry acquisition, both in practical use and research. However, most of the current techniques fail to recognize the checkerboard pattern under distorted, occluded or discontinuous conditions, especially when the checkerboard pattern is dense. This paper proposes a novel checkerboard recognition technique that is robust to noise, surface distortion or discontinuity, supporting checkerboard recognition in dynamic conditions for a wider range of applications. When the checkerboard pattern is used in a projector camera system for geometry reconstruction, by using epipolar geometry, this technique can recognize the corresponding positions of the crossing points, even if the checkerboard pattern is only partly detected.\",\n \"Title: Novel interaction techniques based on a combination of hand and foot gestures in tabletop environments\\nYear: 2012\\n\\nAbstract: Interactive tables, or tabletop devices, employ multi-finger gestures to interact with digital contents on a table's surface. Many studies have confirmed the convenience and intuitiveness of multi-finger gestures performed with the hands. However, there are still some tasks which cannot be conducted effectively by users via two-handed or multi-finger gestures. Given that feet are used occasionally in the real world to support the hands in the performance of complex tasks such as driving a car, we considered that it might be useful to combine foot gestures with hand gestures to enhance user interactions with tabletop environments. In this study, we developed a high-resolution foot sensing platform based on multi-touch techniques known as frustrated total internal reflection and diffused illumination. We then used the device to study the effect of combining hand and foot gestures on tabletop systems by using a 3D drawing application. We conducted user evaluations to compare foot gestures and identified which gestures were most comfortable for performing a 3D model rotation task. We also compared the performance in a 3D drawing task when using only hand gestures with the performance when using hand and foot gestures together. Finally, we discussed how hand and foot gesture combination techniques could provide new user experiences in tabletop environments.\",\n \"Title: A system to visualize different viewpoints for supporting researchers' creativity\\nYear: 1996\\n\\nAbstract: In this paper we describe a system to visualize different viewpoints for supporting researchers' creativity. The system has a text database composed of journal and conference papers. It elicits the viewpoints of the papers automatically and visualizes the semantic relations between them. By using it the users can find new viewpoints on their own research and form creative ideas. To evaluate the system, we carried out the user studies not only for creativity aid but also for communication aid and information retrieval, and confirmed its effectiveness.\",\n \"Title: HATs: interact using height-adjustable tangibles in tabletop interfaces\\nYear: 2011\\n\\nAbstract: We present Height-Adjustable Tangibles (HATs) for table-top interaction. HATs are active tangibles with 4 degrees of freedom that are capable of moving, rotating, and changing height. By adding height as an additional dimension for manipulation and representation, HATs offer more freedom to users than ordinary tangibles. HATs support bidirectional interaction, enabling them to reflect changes in the digital model via active visual feedback and to assist users via haptic feedback. A number of scenarios for using HATs are proposed, including interaction with complex and dependent models and applying HATs as tangible indicator widgets. We then introduce the implementation of HAT prototypes, for which we utilize motor-driven potentiometers to realize bidirectional interaction via the height dimension.\",\n \"Title: Intuitive manipulation techniques for projected displays of mobile devices\\nYear: 2005\\n\\nAbstract: Mobile devices (cellular phone, PDA, etc.) used by many people in their daily lives have so far been personal tools. Due to their multi-functionality, however, the devices have begun to be used by multiple people in co-located situations. This paper discusses near future technologies: a mobile device with a projector and intuitive manipulation techniques by using a video camera mounted on the device. It is difficult to realize a mobile device with a small and light projector that still retains the feature of mobility, so we have developed a system to project displays of mobile devices by tracking their three-dimensional positions and orientations. The proposed system called Hotaru (a firefly, in English) allows users to annotate, rotate or transfer files between multiple devices by touching their projected displays with fingers.\",\n \"Title: CityVoyager: an outdoor recommendation system based on user location history\\nYear: 2006\\n\\nAbstract: Recommendation systems, which automatically understand user preferences and make recommendations, are now widely used in online shopping. However, so far there have been few attempts of applying them to real-world shopping. In this paper, we propose a novel real-world recommendation system, which makes recommendations of shops based on users’ past location data history. The system uses a newly devised place learning algorithm, which can efficiently find users’ frequented places, complete with their proper names (e.g. “The Ueno Royal Museum”). Users’ frequented shops are used as input to the item-based collaborative filtering algorithm to make recommendations. In addition, we provide a method for further narrowing down shops based on prediction of user movement and geographical conditions of the city. We have evaluated our system at a popular shopping district inside Tokyo, and the results demonstrate the effectiveness of our overall approach.\",\n \"Title: Mobile display-based manipulation: an intuitive and interactive technique for manipulating simple robots\\nYear: 2008\\n\\nAbstract: In this paper, we propose the Mobile Display-based Manipulation (MDM) technique for manipulating simple robots such as automated cleaning robots. By capturing images of robots with a camera-attached mobile display and moving it in a three-dimensional space, a user can easily and intuitively manipulate the robots. To verify the validity and effects of the MDM technique, we developed two prototype systems using a handheld display and a projection display. Issues to be investigated and lessons learned through the design and evaluations of the systems are discussed.\",\n \"Title: Evaluation Of Acoustic Imaging System Using Correlation Division In Synthetic Transmit Aperture With Multicarrier Signals\\nYear: 2011\\n\\nAbstract: This paper presents and evaluates a new acoustic imaging system that uses multicarrier signals for correlation division in synthetic transmit aperture (CD-STA). CD-STA is a method that transmits uncorrelated signals from different transducers simultaneously to achieve highspeed and high-resolution acoustic imaging. In CD-STA, autocorrelations and cross-correlations in transmitted signals must be suppressed because they cause artifacts in the resulting images, which narrow the dynamic range as a consequence. To suppress the correlation noise, we had proposed to use multicarrier signals optimized by a genetic algorithm. Because the evaluation of our proposed method was very limited in the previous reports, we analyzed it more deeply in this paper. We optimized three pairs of multicarrier waveforms of various lengths, which correspond to 5th-, 6th-and 7th-order M-sequence signals, respectively. We built a CD-STA imaging system that operates in air. Using the system, we conducted imaging experiments to evaluate the image quality and resolution of the multicarrier signals. We also investigated the ability of the proposed method to resolve both positions and velocities of target scatterers. For that purpose, we carried out an experiment, in which both moving and fixed targets were visualized by our system. As a result of the experiments, we confirmed that the multicarrier signals have lower artifact levels, better axial resolution, and greater tolerance to velocity mismatch than M-sequence signals, particularly for short signals.\",\n \"Title: Interactive and enjoyable interface in museum\\nYear: 2005\\n\\nAbstract: Exhibitions at a scientific museum are usually difficult for ordinary school pupils. To improve the issues of current explanation systems, we use Personal Data Assistant (PDA) devices. Recent PDAs have enough functionality for people to interactively, individually, but it is not easy to assist that school pupils learn scientific knowledge merely using PDA.This research examined the main focus of the design and implementation of visual interfaces for PDAs for such a learning system. We aims the visual interface for PDAs have more interactive and entertainment to engage for learning scientific knowledge. Experiments using two prototype systems(Pi-book and Pit A Pat)implemented in the Flash/MX software toolkit have suggested the effectiveness on the performance and functionality of the proposed method.\",\n \"Title: A Mobile Mixed-Reality Environment for Children's Storytelling Using a Handheld Projector and a Robot\\nYear: 2011\\n\\nAbstract: This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. Pilot studies have been conducted to clarify the design requirements of GENTORO from both technological and practical viewpoints. A user study indicates that GENTORO's ability to enable manipulation of a robot using a handheld projector in a physical space can enhance children's embodied participation in, and their level of engagement with, their storytelling activities, and can support children in designing and expressing creative and original stories.\",\n \"Title: Novel interaction techniques by combining hand and foot gestures on tabletop environments\\nYear: 2011\\n\\nAbstract: Despite the convenience and intuitiveness of multi-touch gestures, there are some tasks that do not allow users to effectively conduct even using two-handed gestures. We propose novel input techniques of combining hand and foot gestures to enhance user interactions on tabletop environments. We have developed an early prototype of a sensor-based foot platform which recognizes subtle foot gestures, designed foot gestures and interactions which support simultaneous users' tasks and obtained their informal feedback.\",\n \"Title: Multiscale Visual Object Detection for Unsupervised Ubiquitous Projection Based on a Portable Projector-Camera System\\nYear: 2010\\n\\nAbstract: Ubiquitous projection is the recent effort that tries to close the gap between the physical world and the virtual world by using a mobile projector. Using a projector and camera together has a conflict of preferred light conditions, making it difficult to implement a robust visual detector while retaining ubiquity. In this paper, we focus on techniques of visual object detection for a portable projector-camera system. The goal is to create a visual detector that requires no guidance from a user and is robust to different light conditions. Our investigation involves the multiscale concept using Canny edge detection as a representative detector. Five image simplification filters applied to the multiscale detection are examined for both accuracy and speed. In addition, preprocessing using histogram equalization and post processing are applied to ensure robustness in a real-world scenario, and to guarantee that the detection will always successfully detect objects using a constant set of parameters defined offline. Finally, we showed that using multiscale detection in a parallel manner can speed up the detection while not affecting the accuracy of the detection.\",\n \"Title: A novel template-based automatic rigging algorithm for articulated-character animation.\\nYear: 2012\\n\\nAbstract: Rigging is a process for creating skeletons used to animate articulated characters. In conventional computer-animation software, this process must be performed manually. Although several automatic rigging algorithms have been proposed, these methods still require user intervention. This paper proposes an automatic algorithm that generates an inverse kinematic skeleton for a character by locating an appropriate template skeleton on the extracted curve skeleton of the input 3D character model. After the curve skeleton is extracted, it is analyzed and classified into an appropriate category. The classification conditions are developed from the characteristics of each kind of real animal. We also develop an algorithm to extract the anatomical meaning of each skeleton segment. On the basis of the classification result, a suitable template skeleton is retrieved from the database. Each bone of the template skeleton can then be located on the appropriate skeleton segment of the input skeleton graph by using the extracted anatomical meanings. In contrast to previous methods, the algorithm does not require the input 3D character models to have certain poses or orientations. Moreover, all processes can be completed without user intervention. Copyright (C) 2012 John Wiley & Sons, Ltd.\",\n \"Title: A fully automatic rigging algorithm for 3D character animation\\nYear: 2011\\n\\nAbstract: This paper proposes an automatic algorithm to generate an inverse kinematic (IK) skeleton for 3D characters. First, a curve skeleton is extracted from the volume inside the character mesh. The extracted curve skeleton is then analyzed and classified by comparing it with the characteristics of templates for real animals. The outcome of this classification step is an associated class for the given 3D character model, together with the meaning of each skeleton segment. Next, each bone of the template skeleton is located in the appropriate skeleton segment of the input skeleton graph. Unlike previous methods, this algorithm does not require an original 3D character model that is created with a restricted pose, topology and orientation. Furthermore, all stages of the process are completed without user intervention.\",\n \"Title: TSaT-MUSIC: a novel algorithm for rapid and accurate ultrasonic 3D localization.\\nYear: 2011\\n\\nAbstract: We describe a fast and accurate indoor localization technique using the multiple signal classification (MUSIC) algorithm. The MUSIC algorithm is known as a high-resolution method for estimating directions of arrival (DOAs) or propagation delays. A critical problem in using the MUSIC algorithm for localization is its computational complexity. Therefore, we devised a novel algorithm called Time Space additional Temporal-MUSIC, which can rapidly and simultaneously identify DOAs and delays of mul-ticarrier ultrasonic waves from transmitters. Computer simulations have proved that the computation time of the proposed algorithm is almost constant in spite of increasing numbers of incoming waves and is faster than that of existing methods based on the MUSIC algorithm. The robustness of the proposed algorithm is discussed through simulations. Experiments in real environments showed that the standard deviation of position estimations in 3D space is less than 10 mm, which is satisfactory for indoor localization.\",\n \"Title: RoboTable: a tabletop framework for tangible interaction with robots in a mixed reality\\nYear: 2009\\n\\nAbstract: Combining table top and tangible user interfaces is a relatively new research area. Many problems remain to be solved before users can benefit from tangible interactive table top systems. This paper presents our effort in this direction. RoboTable is an interactive table top system that enables users to naturally and intuitively manipulate robots. The goal of this research is to develop a software framework for human-robot interaction which combines table top, tangible objects, artificial intelligence and physics simulations and demonstrate the framework with game applications.\",\n \"Title: Video summarization using personal photo libraries\\nYear: 2006\\n\\nAbstract: In this paper, we propose a video summarization system which takes into account users' individual preferences by using their personal photo libraries. Nowadays it is common, especially among people of younger generations, to store thousands of photos inside their PCs and manage them using software such as iPhoto and Picasa. These personal photo libraries contain rich information about the user's tastes, personalities, and lifestyles. Since still photos are in many aspects similar to video as a medium, we assume that these personal photo libraries can be used to estimate users' preferences on video summarization.Our system first divides a movie into short segments, and uses image classification techniques to judge whether each segment is meaningful to the user or not. If many photos with contents similar to the segment can be found in the user's photo library, the segment is judged as being \\\"important\\\" to the user. Conventional image classification techniques use public or commercial photo databases as training data, while our system uses personal photo libraries. This difference leads to the need of several modifications in the classification process.We have implemented a prototype version of our system, and have validated the effectiveness of our approach through evaluating both the accuracy of our image classification algorithm, and users' subjective satisfaction levels of the summarization results.\",\n \"Title: Electronically enhanced board games by integrating physical and virtual spaces\\nYear: 2002\\n\\nAbstract: This paper describes an electronically enhanced board called E 2board. The motivation of our work comes from a traditional board game, which groups of players enjoy in a face-to-face situation by manipulating pieces on a physical board. In order to enhance users’ excitement and immersiveness, a physical board and a virtual world created by a computer are linked together with E 2board. An important function of E 2board is the rapid recognition of massive numbers of different objects. The authors have developed several applications using E 2board: not only games, but also systems for supporting group activities. Some of these applications are shown.\",\n \"Title: Supporting children's rhythm learning using vibration devices\\nYear: 2006\\n\\nAbstract: In this paper, a rhythm instruction tool for school children using vibration devices is discussed. The proposed system called T-RHYTHM is for supporting individual children in playing musical instruments or singing, in solo or ensemble situations. T-RHYTHM provides each child with rhythm patterns of musical pieces through tactile senses, and supports her so that she can recognize her own rhythm without being confused by other children's performances or singing voices. The rhythm of the music given to individual children is determined based on a performance by an accompanist and transmitted to their own vibration devices via a wireless communication. We have evaluated T-RHYTHM in a music class in a Japanese elementary school and gained initial feedback from children and their teacher.\",\n \"Title: CarettaKids: a system for supporting children's face-to-face collaborative learning by integrating personal and shared spaces.\\nYear: 2006\\n\\nAbstract: We developed a new system called CarettaKids that supports face-to-face collaborative learning by children. CarettaKids uses a sensing board based on the Radio Frequency Identification (RFID) technology to support collaboration in a shared space, and the Personal Digital Assistant (PDA) device to support activity in personal spaces. We also introduced this system into an actual classroom environment to evaluate its performance in support for children's collaborative learning, by analyzing the childrens' interaction. As a result, we have confirmed that CarettaKids's feature of transition between two spaces, makes it possible for children to reflect on problems detected in the shared space so as to find solutions in their respective personal space, and to engage in an active exchange of opinions in the shared space, based on ideas generated from personal-space learning.\",\n \"Title: Development of a Full-Body Interaction Digital Game for Children to Learn Vegetation Succession\\nYear: 2013\\n\\nAbstract: In this study, we developed a simulation game called \\\\\\\"Human SUGOROKU\\\\\\\" that simulates vegetation succession of the real forest area in the virtual world. This game consists of a full-body interaction system to enable children to enjoy and learn vegetation succession by playing with their body movement. We conducted an experiment with children and investigated the effects of the full-body interaction through interviews. The results showed that the full-body interaction promotes a sense of immersion in the game. This paper describes the structure of this system and the interview results.\",\n \"Title: Fostering students' participation in face-to-face interactions and deepening their understanding by integrating personal and shared spaces\\nYear: 2007\\n\\nAbstract: In this research, we introduced CarettaKids into the social context of a classroom environment to evaluate whether integration of personal and shared spaces can help promote students' participation in synchronous/co-located interactions in the classroom and deepen their understanding of subject matter. Analysis of videotaped interactions and pre-and posttests clarified the following three points. (1) Students who used CarettaKids presented the simulation results and rules for object arrangement they worked out individually in their respective personal space, by using CarettaKids' function of projecting object arrangements and simulation results from a personal digital assistant onto a sensing board. (2) Many of the students who used CarettaKids examined individually generated ideas collaboratively in the shared space. The patterns of collaborative examination are: (a) Induce a rule for object arrangement from object arrangements devised in personal spaces; (b) Deduce a new object arrangement from the rules discovered in the personal spaces; and (c) Refine the rules discovered in the personal spaces through group discussion. (3) Students who used CarettaKids not only considered all of the three factors, i.e. residential area, industrial area and forest area, but also understood relations between these factors, thereby deepening their understanding of city planning that takes environmental and financial aspects into consideration. We suggest that the degree to which students deepen their understanding is affected by the presence or absence of collaborative examination of individually generated ideas in the shared space.\",\n \"Title: A Scalable Tracking System Using Ultrasonic Communication\\nYear: 2009\\n\\nAbstract: Recently a new method of indoor ultrasonic localisation was introduced. It is called the Phase Accordance Method and the authors claim that with this technology they could measure the 2D coordinates of the transmitter by a single receiver and a single transmission of ultrasound. Also this method is reported to be able to locate static objects more accurately than conventional methods. In this paper we evaluated the ability of the method to locate moving objects. Experiments with a prototype system and a moving robot were conducted, which showed satisfying results. Issues to be investigated in the future work are described.\",\n \"Title: Toss-It: Intuitive Information Transfer Techniques for Mobile Devices Using Toss and Swing Actions\\nYear: 2006\\n\\nAbstract: Mobile devices have acceleratedly penetrated into our daily lives. Though they were originally designed as a communication tool or for personal use, and due to the rapid availability of wireless network technologies, people have begun to use mobile devices for supporting collaborative work and learning. There is, however, a serious problem in mobile devices related to their user interfaces. In this paper, we try to alleviate the problem and propose intuitive techniques for information transfer, which is one of the typical usages of mutually-connected computers. Our system, Toss-It, enables a user to send information from the user's PDA to other electronic devices with a \\\"toss\\\" or \\\"swing\\\" action, like a user would toss a ball or deal cards to others. The implementation of Toss-It consists of three principle parts - gesture recognition, location recognition, and file transfer. We especially describe the details of gesture recognition and location recognition. We then evaluate the practicability and usability of Toss-It through the experiments. We also discuss user scenarios describing how Toss-It can support users' collaborative activities.\",\n \"Title: A correspondence matching technique of dense checkerboard pattern for one-shot geometry acquisition\\nYear: 2010\\n\\nAbstract: This paper presents a correspondence matching technique for a dense checkerboard pattern displayed by a projector-camera system for one-shot geometry acquisition purposes. It does not require color coding or complicated spatial encoding techniques to encode the corresponding positions of corners, and can find corresponding positions for an incomplete checkerboard pattern. We introduce a combination of epipolar geometry and topology constraints in the checkerboard pattern to solve correspondence ambiguities. To verify the feasibility of the technique, we have created a prototype scanning system that can construct the 3D geometry of a scenario for each image frame. The results of our experiments show that the technique can identify correspondences for a checkerboard pattern displayed on discontinuous surfaces and can reconstruct 3D geometry structures in real time.\",\n \"Title: A user-adaptive city guide system with an unobtrusive navigation interface\\nYear: 2009\\n\\nAbstract: In this paper, we describe an intelligent location-aware city guide system, which adapts to each user's preferences, and uses an intuitive \\\"metal detector\\\" interface for navigation. Our system analyzes each user's past location data history to estimate individual preferences, and allows users to find shops that match their tastes in the same way a metal detector would be used to detect metal objects. The procedure with which the system picks out shops that match each user's preferences includes a newly developed place learning algorithm, which can efficiently find frequented places, complete with their proper names (e.g. \\\"The Ueno Royal Museum\\\"). We have conducted a series of evaluation tests at a popular shopping district inside Tokyo, and the results validate the effectiveness of our overall approach.\",\n \"Title: User-adaptive home video summarization using personal photo libraries\\nYear: 2007\\n\\nAbstract: In this paper, we propose a user-adaptive video summarization system which accounts for individual preferences by analyzing contents of the user's personal photo library. Nowadays, it is common practice for people to keep thousands of photos in their PCs, taken with their digital cameras. Due to the similarities in characteristics between video and still photos, we assume that these libraries can be used to infer each user's preferences on video summarization. The system uses image classification techniques to determine which sections of the movie are \\\"important\\\" to the user, and performs summarization by cutting off sections regarded as unimportant, while taking care not to overly disrupt the continuity of the video. We have implemented a prototype of the system, and conducted a series of evaluation tests to assess its effectiveness. The results show that our overall approach has the potential to serve as a powerful automatic/semi-automatic video summarization solution.\",\n \"Title: Human SUGOROKU: learning support system of vegetation succession with full-body interaction interface\\nYear: 2014\\n\\nAbstract: In this study, we developed a simulation game called \\\"Human SUGOROKU\\\" that consists of a full-body interaction system to enable elementary school students to enjoy and learn vegetation succession. The students' sense of immersion is improved by enabling them to play this game using their body movements. We conducted an experiment with the students and investigated the affects of the full-body interaction through questionnaires. The results showed that the full-body interaction promotes a sense of immersion in the game and enhance their understanding of vegetation succession. This paper describes the structure of this system and the questionnaires results.\",\n \"Title: Supporting Self-Directed Learners and Learning Communities with Sociotechnical Environments\\nYear: 2006\\n\\nAbstract: Making learning part of life is an essential challenge for inventing the future of our societies. Lifelong learning is a necessity rather than a possibility or a luxury to be considered. Self-directed learning (often occurring as learning on demand in response to breakdowns) is the dominant form of lifelong learning. The power of the unaided individual mind is highly overrated. Although society often thinks of creative individuals as working in isolation, learning and creativity result in large part from interaction and collaboration with other individuals. Much human creativity is social, and learning communities are needed to cope with the challenges of making learning part of life. This paper articulates existing problems in our current and future world requiring lifelong and self-directed learning and learning communities. It defines conceptual frameworks and it describes four innovative computational environments: (1) domain-oriented design environments , (2) critiquing systems, (3) the Envisionment and Discovery Collaboratory, and (4) Caretta). The paper concludes by providing a set of challenges for the future use of technology to enhance learning based on the conceptual frameworks and the experience and assessment of our system development efforts.\",\n \"Title: A system for constructing private digital libraries through information space exploration\\nYear: 1998\\n\\nAbstract: Digital libraries on the Internet are constructed separately and managed autonomously, and their semantics are different from each other. On the other hand, users of digital libraries have their own information needs. In order for users to fully utilize digital libraries, therefore, a new method for promoting mediation between the semantics of digital libraries and users' information needs is vital. COSPEX (COnceptual SPace EXplorer), proposed in this paper, is a system that can enhance such mediation. Through the exploration of information spaces encompassing multiple digital libraries, users of COSPEX can construct their own private digital libraries.\",\n \"Title: T-RHYTHM: A System for Supporting Rhythm Learning by Using Tactile Devices\\nYear: 2005\\n\\nAbstract: Individual, unaided human abilities are constrained. Media have helped us to transcend boundaries in thinking, working, learning, and collaborating by supporting distributed intelligence. Wireless and mobile technologies provide new opportunities for ...\",\n \"Title: Human SUGOROKU: full-body interaction system for students to learn vegetation succession\\nYear: 2013\\n\\nAbstract: In this study, we developed a simulation game called \\\"Human SUGOROKU\\\" that consists of a full-body interaction system to enable elementary school students to enjoy and learn vegetation succession. The students' sense of immersion is improved by enabling them to play this game using their body movements. We conducted an experiment with the students and investigated the affects of the full-body interaction through interviews. The results showed that the full-body interaction promotes a sense of immersion in the game. This paper describes the structure of this system and the interview results.\",\n \"Title: Hotaru: intuitive manipulation techniques for projected displays of mobile devices\\nYear: 2005\\n\\nAbstract: Mobile devices (cellular phone, PDA, etc.) have so far been personal tools. Due to their evolution to multi-functionality,\\n however, the devices have begun to be used by multiple people in co-located situations. This paper discusses near future technologies:\\n a mobile device with a projector and intuitive manipulation techniques by using a video camera mounted on the device. In today’s\\n technologies, it is difficult to realize a mobile device with a small and lightweight projector that still retains the feature\\n of mobility. Therefore, we have developed a system to project displays of mobile devices on a table, a floor, or a wall, by\\n tracking their three-dimensional positions and orientations and using an existing LCD projector. The proposed system called\\n Hotaru (a firefly, in English) allows users to annotate/rotate a picture or a document in a mobile device by touching its projected\\n display with their fingers. Users can intuitively transfer a file between multiple devices by making their projected displays\\n overlapped. Informal evaluations of Hotaru indicated that the proposed manipulation techniques could effectively support multiple people in co-located situations in\\n conducting their tasks.\",\n \"Title: Musex: A System for Supporting Children's Collaborative Learning in a Museum with PDAs\\nYear: 2004\\n\\nAbstract: Using handheld devices in educational environments has begun to be recognized as suitable. Due to the drastic revisions in Japanese curriculum standards for elementary school children, new theories, systems and practices to support children in their learning are required. Therefore, we focused attention on science museums, which are different learning environments from schools. In this paper, we propose a system called Musex, which is used to support children in learning and exploring collaboratively in a museum with two PDAs (Personal Digital Assistants). Through Musex, children can collaboratively challenge some questions which are related to exhibitions. Solving the questions let children pay their attention to exhibitions naturally and understand contents of exhibitions more. We evaluated the system in a Japanese science museum and confirmed its effectiveness.\",\n \"Title: Method to assist the building and expression of subjective concepts and its application to design problems\\nYear: 1994\\n\\nAbstract: The paper discusses how computers can assist human creativity. A support system has been built and applied to the domain of automobile design. The system uses multidimensional data and statistical methods, and configures a space for inspiring the users' design activity. In the first step, it assists them in forming individual design concepts. In the second step, it assists them in deciding their target design concepts. It has been confirmed that it works effectively through experiments. Some of the open questions on creativity support systems are also discussed.\",\n \"Title: Towards the Integration of Physical and Virtual Worlds for Supporting Group Learning\\nYear: 2000\\n\\nAbstract: In this paper, we describe a system that integrates physical worlds (physical cities) and virtual worlds (digital cities), and its applications to supporting group learning. We have so far constructed several systems for supporting collaborative learning. One of the aims of CSCL (Computer-Supported Collaborative Learning) is to promote mutual learning through interactions and discussions among learners. Our previous experiments, however, have shown that these systems may not be so effective for supporting interactions and discussions at times. In order to enhance interactions further, a system should support externalization of each learner in an easily recognizable manner. Through such externalization, learners can actively collaborate or conflict with each other through discussions. The proposed system integrates a board game and a computer simulation, is used for studying urban planning and environmental problems. Each learner externalizes and represents his/her own ideas on a board game, which allows him/her to actively participate in a learning situation and to share the representations with other learners. The computer simulation calculates and visualizes the status of the city being constructed on the board game, in terms of air pollution, water pollution, etc.. Thirty fifth-grade pupils who had studied environmental problems in school participated in the experiments. The experiments showed that our system is effective for enhancing interactions, activating discussions, and raises learners' engagement.\",\n \"Title: RoboTable2: a novel programming environment using physical robots on a tabletop platform\\nYear: 2011\\n\\nAbstract: In this paper, we propose a novel environment called RoboTable2 that supports users with limited programming knowledge or experience in conducting robot programming. We have devised a tabletop platform that can simultaneously recognize multi-touch input and track physical robots, enabling users to conduct robot-programming tasks in an intuitive manner. A user study comparing the proposed and a conventional graphical programming environment was conducted, involving ten university students with no programming experience. The effects of the proposed environment were clarified via video analysis, questionnaires and usage logs. A pilot study was also conducted to verify how easily users could design and develop applications on RoboTable2. The lessons learned with respect to design guidelines for the proposed programming environment and issues for investigation are discussed.\",\n \"Title: KIKIWAKE: sound source separation system for children-computer interaction\\nYear: 2013\\n\\nAbstract: In general living environments, in order to separate children's voices from backgrounds noise, we developed a sound separation system by a microphone array. We created a game by use of this developed system, and conducted evaluation experiment intended for elementary school children. As a result, we confirmed this system could separate 3 voices, and the game promotes children's interest in or concerns about a microphone array in a quantitative way.\",\n \"Title: Toward an Interactive Museum Guide System with Sensing and Wireless Network Technologies\\nYear: 2002\\n\\nAbstract: In this paper, we describe an interactive guide system for kids in museums. The system uses a sensing board which can rapidly recognize types and locations of multiple objects, and creates an immersive environment by giving users visual and auditory feedback to their manipulations on the board. The purpose of the system is to attract users' interests in a real exhibition by allowing them to interact with the corresponding virtual exhibition on the board, and providing them with its information. We have evaluated the system in a museum. From the interviews and questionnaires, we have confirmed that it is easy for kids to use the system and it can raise their motivation for visiting real exhibitions.\",\n \"Title: Skeleton-growing: a vector-field-based 3D curve-skeleton extraction algorithm\\nYear: 2010\\n\\nAbstract: The vector-field-based method is one of the 3D curve-skeleton extraction algorithms. Typically, critical points in the vector field inside 3D objects are connected to form the curve-skeleton. However, critical points usually do not distribute to all important parts of the 3D object. Therefore, other features are used to produce a reliable result. Although this strategy can deliver a curve-skeleton that captures all of the important parts, the curve-skeleton usually comes with unnecessary segments. This paper proposes the skeleton-growing algorithm that automatically produces the curve-skeleton with small amounts of such segments. It searches for a set of high-curvature boundary voxels as starting points to find a set of suitable seed points that will be used to grow the curve-skeleton. We propose an unnecessary segment removal algorithm that can reduce the skeleton-noise density. A direction-selection algorithm is developed to avoid searching in irrelevant directions. The proposed method can produce a single reliable result curve-skeleton that could be applied in many different applications, including matching, animation, and visualization.\",\n \"Title: Dual mode IR position and state transfer for tangible tabletops\\nYear: 2011\\n\\nAbstract: This paper presents a method for tracking multiple active tangible devices on tabletops. Most tangible devices for tabletops use infrared to send information about their position, orientation, and state. The method we propose can be realized as a tabletop system using a low-cost camera to detect position and a low-cost infrared (IR) receiver to detect the state of each device. Since two different receivers (camera and IR-receiver) are used simultaneously we call the method dual mode. Using this method, it is possible to use devices with a large variation of states simultaneously on a tabletop, thus having more interactive devices on the surface.\",\n \"Title: GENTORO: a system for supporting children's storytelling using handheld projectors and a robot\\nYear: 2009\\n\\nAbstract: This paper describes a system called GENTORO that uses a robot and a handheld projector for supporting children's storytelling activities. GENTORO differs from many existing systems in that children can make a robot play their own story in a physical space augmented by mixed-reality technologies. A user study conducted in collaboration with elementary school children and teachers indicates that GENTORO's features can enhance children's embodied participation in, and their level of engagement with, their storytelling activities, and can support children in designing and expressing creative and original stories\",\n \"Title: Novel interaction techniques using touch-sensitive tangibles in tabletop environments\\nYear: 2012\\n\\nAbstract: In this work, we propose techniques for interaction that use a touch-sensitive tangible to assist 3D manipulation in tabletop applications. The objective of this research is to investigate the effectiveness and user satisfaction with this combination for performing virtual object manipulation in tabletop environments. A prototype of a touch-sensitive tangible was constructed and some of the proposed techniques were implemented, namely 3D translation and rotation. We conducted a pilot study to compare 3D manipulation on the tabletop with and without the tangible, from which we found that the touch-sensitive tangible was useful for 3D manipulation tasks.\",\n \"Title: A system for supporting group learning that enhances interactions\\nYear: 1999\\n\\nAbstract: In this paper, we describe and evaluate a system for supporting group learning that enhances interactions among learners. To date we have constructed several systems for supporting collaborative learning. One of the aims of CSCL is to promote mutual learning through interactions and discussions among learners. Our previous experiments, however, have shown that these systems may not be so effective for supporting interactions and discussions at times. In order to enhance interactions further, a system should support externalization of each learner in an easily recognizable manner. Through such externalization, learners can actively collaborate or conflict with each other through discussions.The proposed system integrates a board game and a computer simulation, and is used for studying urban planning and environmental problems. Each learner externalizes and represents his/her own ideas on a board game, which allows him/her to actively participate in a learning situation and to share the representations with other learners. The computer simulation helps the learners to understand the status of the town constructed on the board game.Several experiments were carried out in a public elementary school. The results show that our system is effective for enhancing interactions, discussions and learner engagement.\",\n \"Title: A robust and dynamic scene geometry acquisition technique for a mobile projector-camera system\\nYear: 2009\\n\\nAbstract: This paper presents a new structured light pattern generation technique, which allows acquisition of scene geometry from a single image, under various projection conditions with relatively high acquisition density. We construct the pattern by using the geometrical constraints of the projector-camera system, and solve the correspondence problem based on the local connectivity of the feature points and edges of the projection pattern. This method is robust from image processing perspective, and allows rapid geometry scanning using a mobile projector-camera system.\",\n \"Title: What can Children Learn through Game-based Learning Systems?\\nYear: 2007\\n\\nAbstract: In this talk, I will present key ideas and underlying philosophies of our research projects. I will also describe about several systems for supporting children's collaborative learning, such as CarettaKids, T-RHYTHM, and so on. Lessons learned through the design and e, aluation of these systems, and some thoughts for DIGITEL researches will be discussed.\",\n \"Title: 3D FDM-PAM: rapid and precise indoor 3D localization using acoustic signal for smartphone\\nYear: 2014\\n\\nAbstract: In this paper, we present an indoor 3D positioning method for smartphones using acoustic signals. In our proposed 3D Frequency Division Multiplexing--Phase Accordance Method (3D FDM--PAM), four speakers simultaneously emit burst signals comprising two carrier waves at different frequencies to enable the rapid calculation of the position of the smartphone. Through experiments, we show that 3D FDM--PAM can achieve a standard deviation of less than 2.8 cm at 7.8 measurements per second. The worst positioning error was 48.3 cm at the 95th percentile. We investigate the causes of error and discuss potential improvements to the localization performance.\",\n \"Title: BESIDE: Body Experience and Sense of Immersion in Digital Paleontological Environment\\nYear: 2015\\n\\nAbstract: We are developing an immersive learning support system for a paleontological environment within a museum. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first stage of this project, we have developed a prototype system that allows learners to experience the paleontological environment. Here, we evaluate the operability of the system, degree of learning support, and sense of immersion for primary schoolchildren. This paper summarizes the current system and describes the evaluation results.\",\n \"Title: KIKIWAKE: participatory design of language play game for children to promote creative activitybased on recognition of japanese phonology\\nYear: 2014\\n\\nAbstract: This study proposes a system for supporting the Shotoku Taishi game, which is a language play game that uses the voice of children. The Shotoku Taishi game is a group game in which multiple people presenting a problem vocalize different words at the same time and the respondents are required to guess what the combination of the words is. The authors developed and implemented a system using a microphone array to extract the voice of a specific person presenting a problem in this game. The participants were 36 elementary school students whose native language was Japanese. The results showed that the participants were enjoying the Shotoku Taishi game and that this group activity was a creative activity that deepened their awareness of the Japanese language.\",\n \"Title: Smart Phone Localization Method Using Dual-Carrier Acoustic Waves\\nYear: 2013\\n\\nAbstract: We describe an indoor localization technique for smart phones. Our new method, called the Frequency Division Multiplexing Phase Accordance Method (FDM-PAM), uses a beat called a sync pattern composed of a pair of sinusoidal waves with slightly different frequencies, which is similar to our original ultrasound ranging technique called the Phase Accordance Method (PAM). By generating multiple sync patterns with different central frequencies and transmitting them from different speakers, FDM-PAM conducts time-difference-of-arrival (TDOA) multilateration for localizing smart phones. In the current implementation of FDM-PAM, the 2D indoor position of a smart phone can be estimated. Three sync patterns are generated by using two out of six sinusoidal waves with frequencies ranging from 14.75 kHz to 17.25 kHz. The transmission of the sync pattern from the speakers lasts 4 ms. Through experiments, we have confirmed that FDM-PAM achieves accuracy of around 10 cm using only a short burst transmission, which indicates that the localization technique is sufficiently rapid and accurate.\",\n \"Title: Discovering how other pupils think by collaborative learning in a classroom\\nYear: 2000\\n\\nAbstract: The authors have so far developed a system that supports collaborative learning and evaluated it in school education. The system integrates physical and virtual worlds to teach urban planning and environmental problems by game playing by the pupils themselves. Intensive experiments with the system have proven that it can support the externalization of learners' thinking, active participation, interactions among them, and discussions in a learning situation. The paper addresses the effects of collaborative learning, and discusses how pupils discover the way of thinking of other pupils during game play\",\n \"Title: Shepherd: An Interface for Overcoming Reference Frame Transformations in Robot Control\\nYear: 2006\\n\\nAbstract: In this paper, we propose a system called Shepherd that allows a user to manipulate robots such as radio controlled cars from his viewpoint. The user of Shepherd can intuitively control the robots by capturing images of robots through a camera mounted on a mobile device, and moving it. User studies of Shepherd indicated that users could manipulate the robot in an intuitive manner.\",\n \"Title: A Novel Framework for 3D Computer Animation Systems for Nonprofessional Users Using an Automatic Rigging Algorithm\\nYear: 2012\\n\\nAbstract: This paper presents a novel framework for developing automatic animation systems, which accept a 3D model that is created at runtime. Previous systems cannot deal with such a 3D model because it needs to be prepared by a manual process (rigging) that may not be suitable for nonprofessional users. The proposed framework solves this problem by employing an automatic rigging algorithm. Our algorithm can generate an animation skeleton for a given 3D model automatically, including the anatomical meaning of each joint. The relationship between motion data and this animation skeleton is created by identifying the corresponding joints in the motion data and the skeleton. The motion data for each joint is transferred automatically to the 3D model that has been rigged via our automatic rigging algorithm. Because all processes can be completed without any user intervention, an animation system for nonprofessional users is therefore available. We also discuss several motion editing techniques that can be used to generate new motion data without complex processing.\",\n \"Title: An intuitive computer animation system for enhancing human creativity\\nYear: 2013\\n\\nAbstract: Computer animation can be used in a wide variety of applications, including storytelling. However, even producing low-quality computer animation requires a significant effort by professional users. Although it should be a tool capable of enhancing creativity in anyone, it is currently too difficult for some users. This paper presents a framework for a computer animation system that can reduce the difficulty of animation authoring, bringing such tasks within the reach of users at all levels. With this framework, users can focus on the story alone, rather than on details of the animation-creation method. The proposed system can therefore enhance users' creativity in story creation. The proposed framework comprises three modules, namely modeling, motion, and animation. Interaction with these modules is via simple actions, enabling computer animation to be created by anyone. A users' study is also presented in this paper to measure the performance of the proposed system in terms of ease of use and the capacity to enhance human creativity.\",\n \"Title: A puppet interface for the development of an intuitive computer animation system\\nYear: 2012\\n\\nAbstract: In this paper, we introduce a puppet interface for the development of an intuitive animation system. Our puppet interface does not require any special devices and any type of puppet can be used. The puppet interface is developed by attaching ten visible markers onto a puppet. The user can manipulate the pose of the puppet interface to produce the desired motion in front of a camera. The puppet's joint angle information is captured by the camera and used to retrieve a suitable motion from a motion database. The retrieved motion data is transferred to a 3D character model to generate an animation. To avoid the occlusion problem, we propose an algorithm that estimates the joint angle by determining the position and rotation of markers adjacent to the occluded marker. Experiments confirmed that our proposed algorithm can generate correct results, although some occluded markers remained.\",\n \"Title: Using Image Features and Eye Tracking Device to Predict Human Emotions Towards Abstract Images.\\nYear: 2015\\n\\nAbstract: Nowadays, emotional semantic image retrieval system enables users to access images that they want in a database according to emotional concept. This leads to affective image classification task which recently attracts researchers' attention. However, different users may experience different emotions depending on where, in the image, they are gazing on. This paper presents an improved prediction method by taking into account the users eye movement as implicit feedback while they are looking at the image. Our experimental results show that using both eye movement information and image feature together to determine users emotion gave more accurate predictions than using image feature alone.\",\n \"Title: Light-Synchronized Acoustic Toa Measurement System For Mobile Smart Nodes\\nYear: 2014\\n\\nAbstract: We describe a novel time-synchronization technique for mobile smart nodes. We capture modulated LED light with a video camera, which is usually built into a smart node. The CMOS image sensor of a video camera does not take a snapshot at a certain time. Instead, the sensor captures data on a line-by-line basis and the sensor output consists of lines taken at slightly different times. Therefore, we can extract time information from the image. This can be used for time synchronization for time-of-arrival (ToA) measurements. In this paper, we describe the fundamentals and an experiment using light-synchronized acoustic ToA measurements with mobile smart nodes. The acknowledged precision of the obtained time information is equivalent to 5.8 mm with an airborne sound wave.\",\n \"Title: SyncSync: Time-of-arrival based localization method using light-synchronized acoustic waves for smartphones\\nYear: 2015\\n\\nAbstract: In this paper we describe SyncSync, a novel time-of-arrival (ToA) localization method for smartphones. ToA measurements generally show better precision than time-difference-of-arrival measurements, but ToA systems require a synchronization mechanism between anchor and mobile nodes. For this synchronization, we employ modulated light with an acoustic signal for the time-of-flight distance measurement. These are detected by the smartphone's video camera and microphone. The time resolution in consumer video cameras is typically only a few tenths of a second, but by utilizing a CMOS image sensor's rolling shutter effect we obtain synchronization resolutions of a few microseconds, sufficient for precise acoustic ToA measurement. Experiments confirm operation of the system with localization errors within 10 mm.\",\n \"Title: A rapid and accurate time-synchronization technique for acoustic localization using modulated illumination\\nYear: 2015\\n\\nAbstract: This paper presents a rapid and accurate time-synchronization technique for acoustic localization. Two LED arrays for modulated illumination and an off-the-shelf camera are used. An equation that specifies the time difference between them accurately and precisely is proposed. Experiments in real environments show that the proposed technique using rectangular signals can achieve time synchronization to within 29.4 μs (5.94 μs standard deviation) and acoustic ranging to within 9.9 mm (2.01 mm standard deviation) for a measurement period of 0.1 s. Because of the smaller standard deviation in comparison with the error, it is indicated that there exist systematic errors to be removable. This technique will enable the implementation of an acoustic 3D localization system for mobile devices such as tablet PCs and smartphones based on time-of-arrival trilateration, which is more accurate than positioning taking a time-difference-of-arrival approach. Theoretical analyses for modulated illumination considering a camera exposure time clarify how an optimally modulated signal is designed for achieving rapid and accurate time synchronization.\",\n \"Title: Toward a platform for collecting, mining, and utilizing behavior data for detecting students with depression risks\\nYear: 2015\\n\\nAbstract: In this paper, we present our plan for constructing a platform for collecting, mining, and utilizing behavior data for detecting students with depression risks. Unipolar depression makes a large contribution to the burden of disease, being at the first place in middle- and high-income countries. We survey descriptors of depressions and then design a data collection platform in a classroom based on the assumption that such descriptors are also effective to students with depression risks. Visual, acoustic, and e-learning data are chosen for collection and various issues including devices, preprocessing, and consent agreements are investigated. We also show two kinds of utilization scenarios of the collected data and introduce several techniques and methods we developed for feature extraction and early detection.\",\n \"Title: Science Education Enhancement within a Museum using Computer-human Interaction Technology.\\nYear: 2016\\n\\nAbstract: We are developing an immersive learning support system for paleontological environments in museums. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first step toward realizing an immersive learning support system for museums, Yoshida et al. developed and evaluated a prototype system. However, their system cannot learn about certain paleontological features such as the names of extinct animals and their characteristics. Therefore, we developed an improved version of this system that allows for an enriched knowledge of paleontological environments, focusing in particular on extinct animals and plants and the ecological environment. Here, we evaluate the systemâs learning assistant and immersive features insofar as they are directed toward children in primary school. This paper summarizes the current system and describes the evaluation results.\",\n \"Title: Reducing Redundancy With Unit Merging For Self-Constructive Normalized Gaussian Networks\\nYear: 2016\\n\\nAbstract: In this paper, a Normalized Gaussian Network (NGnet) is introduced for online sequential learning that uses unit manipulation mechanisms to build the network model self-constructively. Several unit manipulation mechanisms have been proposed for online learning of an NGnet. However, unit redundancy still exists in the network model. We propose a merge mechanism for such redundant units, and change its overlap calculation in order to improve the identification accuracy of redundant units. The effectiveness of the proposed approach is demonstrated in a function approximation task with balanced and imbalanced data distributions. It succeeded in reducing the model complexity around 11% on average while keeping or even improving learning performance.\",\n \"Title: Multiple-Player Full-Body Interaction Game to Enhance Young Children's Cooperation.\\nYear: 2016\\n\\nAbstract: We have developed a full-body interaction game that allows children to cooperate and interact with other children in small groups. The aim of the game developed in this study is to encourage cooperation between children. The game requires two children to jump together at the same time. In a series of experiments, we observed children using several strategies to coordinate the timing of their jumps, such as shouting to one another and watching each other. The results of a questionnaire to evaluate the proposed interactive game indicate that children strategize to cooperate with each other while enjoying the game. Therefore, the game enables children to cooperate with others using bodily movements.\",\n \"Title: Participatory Design of UKIYO-E Game for Children to Support Art Appreciation Based on Interacting with Pictures.\\nYear: 2016\\n\\nAbstract: We are developing an art-appreciation system that will provide learning information about pictures while generating interest in the pictures themselves. This system can provide learning information on pictures by talking to an artist or people portrayed in the pictures using voice recognition. Furthermore, the system operates through movement and location of the user, and it generates sensation such that the user feels he/she is in the pictures, thus actively appreciating the pictures. As the first step toward this system, we have developed a system that provides learning information to the user by actively talking using ukiyo-e. Here, we quantitatively evaluate this system for primary schoolchildren and determine whether the user is interested in the pictures while talking to the pictures using voice recognition measured by electrodermal activity. In this paper, we summarize the current system and describe two evaluation results.\",\n \"Title: Experience-based learning support system to enhance child learning in a museum: touching real fossils and \\\"experiencing\\\" paleontological environment.\\nYear: 2015\\n\\nAbstract: This paper presents a support system to assist learning within museums. Museums represent important places of scientific learning for children. However, because the main learning method in museums is the study of displayed specimens and their corresponding explanations, the motivation of a child to learn is low. Hence, we are developing an experience-based learning support system such as entertainment that will enable learners to enhance their motivation to learn in any museum. We develop two systems to realize experience-based entertainment. One is \\\\\\\"Live Biblia,\\\\\\\" which is a digital installed book system that uses real fossil. Another is the immersive learning system we called \\\\\\\"Body Experience and Sense of Immersion in Digital paleontological Environment\\\\\\\" or \\\\\\\"BESIDE,\\\\\\\" which enables learners to explore a virtual paleontological environment. In this paper, we present a summary of the current system of Live Biblia and BESIDE.\",\n \"Title: Optimally Modulated Illumination for Rapid and Accurate Time Synchronization.\\nYear: 2017\\n\\nAbstract: This paper presents a rapid and accurate time-synchronization technique using an LED and an off-the-shelf camera. We discuss optimally modulated illumination as a function of camera exposure time through theoretical analysis and derive its mathematical representation. Experiments in real environments with a single LED and 60 fps camera show that the proposed technique can achieve time synchronization within a 17.4 $\\\\\\\\mu$ s error at the 90th percentile using only four frames (a measurement time of 0.067 s). Comparative experiments with computer simulations prove that the proposed technique using optimally modulated illumination to camera exposure time needs less CPU time than that using nonoptimally modulated illumination. The performance of the proposed technique derived from the noise distribution of intensities in captured images agrees closely with the experimental results, enabling time synchronization to be estimated within a confidence interval at a given confidence level. Possible applications to be developed by utilizing features of the proposed technique are described.\",\n \"Title: Whisper to normal speech conversion using pitch estimated from spectrum.\\nYear: 2016\\n\\nAbstract: A systematic method to connect a whispered vowel to its perceived pitch is presented.A regression function to predict the perceived pitch from the spectral information of the whispered speech is obtained.A whispered-to-normal speech converter is constructed and the pitch accents perceived in whispered Japanese words were recovered by the conversion. We can perceive pitch in whispered speech, although fundamental frequency (F0) does not exist physically or phonetically due to the lack of vocal-fold vibration. This study was carried out to determine how people generate such an unvoiced pitch. We conducted experiments in which speakers uttered five whispered Japanese vowels in accordance with the pitch of a guide pure tone. From the results, we derived a multiple regression function to convert the outputs of a mel-scaled filter bank of whispered speech into the perceived pitch value. Next, using this estimated pitch value as F0, we constructed a system for conversion of whispered speech to normal speech. Since the pitch varies with time according to the spectral shape, it was expected that the pitch accent would be kept by this conversion. Indeed, auditory experiments demonstrated that the correctly perceived rate of Japanese word accent was increased from 55.5% to 72.0% compared with that when a constant F0 was used.\",\n \"Title: A spot-controllable data transfer technique using COTS speakers\\nYear: 2016\\n\\nAbstract: This paper describes a spot-controllable data-transfer method. The proposed method generates a beam-shaped spot using two commercial off-the-shelf speakers. In our method, a symbol consists of a pair of sinusoidal waves having different angular frequencies. The width and direction of a beam-shaped spot are controlled by the angular-frequency difference between the sinusoidal waves and the transmission-time difference between the two speakers. Multiple spots can be generated by transmitting multiple pairs of sinusoidal waves based on the principle of orthogonal frequency-division multiplexing. By over-lapping multiple beam-shaped spots, the locations and sizes of the areas enabled to receive data are controllable. Experiments using four speakers and computer simulation show that the proposed method can generate controllable spots. An analysis of the errors in a real indoor environment indicate that they are caused by multipath signals, radiation damping of transmitted signals, and the incident/output angle characteristics of the microphone and speakers.\",\n \"Title: Online EM for the Normalized Gaussian Network with Weight-Time-Dependent Updates.\\nYear: 2016\\n\\nAbstract: In this paper, we propose a weight-time-dependent (WTD) update approach for an online EM algorithm applied to the Normalized Gaussian network (NGnet). WTD aims to improve a recently proposed weight-dependent (WD) update approach by Celaya and Agostini. First, we discuss the derivation of WD from an older time-dependent (TD) update approach. Then, we consider additional aspects to improve WD, and by including them we derive the new WTD approach from TD. The difference between WD and WTD is discussed, and some experiments are conducted to demonstrate the effectiveness of the proposed approach. WTD succeeds in improving the learning performance for a function approximation task with balanced and dynamic data distributions.\",\n \"Title: Analytical Incremental Learning: Fast Constructive Learning Method for Neural Network.\\nYear: 2016\\n\\nAbstract: Extreme learning machine ELM is a fast learning algorithm for single hidden layer feed-forward neural network SLFN based on random input weights which usually requires large number of hidden nodes. Recently, novel constructive and destructive parsimonious CP and DP-ELM which provide the effectiveness generalization and compact hidden nodes have been proposed. However, the performance might be unstable due to the randomization either in ordinary ELM or CP and DP-ELM. In this study, analytical incremental learning AIL algorithm is proposed in which all weights of neural network are calculated analytically without any randomization. The hidden nodes of AIL are incrementally generated based on residual error using least square LS method. The results show the effectiveness of AIL which has not only smallest number of hidden nodes and more stable but also good generalization than those of ELM, CP and DP-ELM based on seven benchmark data sets evaluation.\",\n \"Title: Hinge Loss Projection for Classification.\\nYear: 2016\\n\\nAbstract: Hinge loss is one-sided function which gives optimal solution than that of squared error SE loss function in case of classification. It allows data points which have a value greater than 1 and less than $$-1$$-1 for positive and negative classes, respectively. These have zero contribution to hinge function. However, in the most classification tasks, least square LS method such as ridge regression uses SE instead of hinge function. In this paper, a simple projection method is used to minimize hinge loss function through LS methods. We modify the ridge regression and its kernel based version i.e. kernel ridge regression so that it can adopt to hinge function instead of using SE in case of classification problem. The results show the effectiveness of hinge loss projection method especially on imbalanced data sets in terms of geometric mean GM.\",\n \"Title: Integration Of Ultrasonic Sensors And Kinect Sensors For People Distinction And 3d Localization\\nYear: 2013\\n\\nAbstract: The method proposed here for 3D position measurement and identification of individuals by integrating ultrasonic and Kinect sensors uses ultrasonic transmitter tags with unique identifiers. Ultrasonic sensors measure the 3D positions of and identify tagged individuals, but cannot make measurements if there are no receivers in the direction of ultrasonic waves from transmitters. Kinect sensors measure 3D positions of individuals and track them with OpenNI, but Kinect sensors cannot make measurements if occlusion occurs due to the overlapping of individuals. Evaluation results show that the method proposed here is more robust than methods only using either ultrasonic or Kinect sensors.\",\n \"Title: Depth information based separation of moving speakers' voices from mixed recordings.\\nYear: 2016\\n\\nAbstract: This paper proposes a method for separating the voice of a signal person from the voices of multiple speakersu0027 in a mixed recording. When the sounds of multiple speakers are present when a voice recognition system is operating, the quality of speech recognition decreases. The proposed method separates the sound of multiple speakers using signal processing techniques and a microphone array. The position of the speaker is also required; however, the microphone array cannot be used for this purpose. Consequently, the position of the speaker was determined using the Kinect V2 depth image sensor. An experiment was performed to separate a signal voice from many voices. The results of the experiment show that, it is possible to separate two voices using the proposed technique.\",\n \"Title: Belong: Body Experienced Learning Support System Based On Gesture Recognition Enhancing The Sense Of Immersion In A Dinosaurian Environment\\nYear: 2017\\n\\nAbstract: As the first step toward realizing an immersive learning support system for museums, Yoshida et al. developed and evaluated a prototype system. However, this system was problematic in that it could only be operated by using simple body movements. Moreover, the other problem was that learning about paleontology itself cannot be performed only by learning about a paleontological environment. Therefore, we developed an immersive learning support system \\\"BELONG\\\" as an upgraded version of the above-mentioned system. Using a recognizer capable of gesture recognition, the system can be operated using complicated body movements. The improved system enables learners to enhance their sense of immersion in a paleontological environment and learn about the fossil itself and its paleontology. This paper summarizes the prototype of \\\"BELONG\\\" and describes the experiments that were performed to evaluate its ability to achieve learning support and immersion.\",\n \"Title: Development Of Experiential Learning System Based On The Connection Between Object Models And Their Digital Contents Collaboration Between Tangible Interface And Computer Interaction\\nYear: 2017\\n\\nAbstract: Experiential learning is effective for educating children. However, there are many issues associated with this technique. In this study, we describe the development of a learning support system using which learners can experience touching and viewing in real and virtual environments. In the first stage of our study, we develop a larval mimesis experience system consisting of a Kinect sensor, larval models, and load sensors. The system is controlled using Arduino. Using the proposed system, learners can exercise full body interaction in the virtual environment; specifically, they can experience how larva models are observed in the real environment. The operation of this system was experimentally evaluated by learners from a primary school. The results indicate that the system is suitable for the use of children. In addition, the effectiveness of the learning support was evaluated by using a questionnaire. This paper summarizes the development of the proposed system and describes the evaluation results.\",\n \"Title: Development Of Gesture Recognition Sub-System For Belong Increasing The Sense Of Immersion For Dinosaurian Environment Learning Support System\\nYear: 2017\\n\\nAbstract: We are developing an immersive learning support system for paleontological environments in museums. The system measures the body movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment. Conventional systems are only able to recognize simple body movements, which is insufficient to completely immerse learners in the paleontological environment. On the other hand, when they need to perform complicated body movements, learners move their bodies eagerly while thinking. This emphasizes the importance of developing a sub-system capable of recognizing complicated body movements. In this paper, we describe a sub-system developed to recognize the body movement of the most important learner in the immersive learning support system.\",\n \"Title: Satoyama: Time-Limited Decision Game For Students To Learn Hundreds Years Forestry Management\\nYear: 2017\\n\\nAbstract: Global environmental problems continue to worsen. In this situation, it is important to understand and experience changes in the natural environment in realistic ways. However, it was difficult to experience these changes in real time because they happen over large time scales. To overcome this problem, the authors developed a game-like learning tool that enables players to learn about vegetation succession. This game is Windows-based and enables players to simulate the conservation of SATOYAMA, rural natural areas. The player selects the actions within a designated time and the vegetation succession of the SATOYAMA changes according to that action. At the end of this game, the score is based on the SATOYAMA conserved by the player. Thirty-seven students participated in this experiment whose result suggested that this game would enable children to develop an interest in vegetation succession and motivate them to learn about it.\",\n \"Title: Laughing voice recognition using periodic waveforms and voice-likeness features.\\nYear: 2016\\n\\nAbstract: With a goal of advancing human-machine collaboration, we propose a method to recognize a laughing voice. A previous study that proposed a laughing voice recognition method was based on the periodic waveform feature of the laughing voice. However, identifying laughing voices from waveforms is problematic, because this can result in false positive results. To overcome this problem, we propose a laughing voice recognition method that incorporates a voice-likeness feature. In addition, we make a laughing voice recognition system using our proposed method. To confirm the efficacy of the laughing voice recognition method, we evaluated this system. In our evaluation, we were able to correctly recognize laughing voice at a high success rate of 97%. In comparison with the previous study, the recognition rate improved by 18%; therefore, our proposed method can be considered an effective in recognizing laughing voice.\",\n \"Title: Time-Of-Arrival-Based Indoor Smartphone Localization Using Light-Synchronized Acoustic Waves\\nYear: 2017\\n\\nAbstract: We describe SyncSync, a time-of-arrival (ToA)-based localization method for smartphones. In general, ToA measurements show better precision than time-difference-of-arrival (TDoA) measurements, although ToA systems require a synchronization mechanism between anchor and mobile nodes. For this synchronization, we employ modulated LED light with an acoustic wave for time-of-flight distance measurements. These are detected by the smartphone's video camera and microphone. The time resolution in consumer video cameras is typically only a few tenths of a second, but by utilizing a CMOS image sensor's rolling shutter effect we obtain synchronization resolutions of a few microseconds, which is sufficient for precise acoustic ToA measurements. We conducted experiments to confirm operation of the system, and obtained ToA localization errors within 10 mm. The characteristics of the error distributions for both TDoA and ToA measurements were explained by dilution of precision.\",\n \"Title: An Online Self-Constructive Normalized Gaussian Network With Localized Forgetting\\nYear: 2017\\n\\nAbstract: In this paper, we introduce a self-constructive Normalized Gaussian Network (NGnet) for online learning tasks. In online tasks, data samples are received sequentially, and domain knowledge is often limited. Then, we need to employ learning methods to the NGnet that possess robust performance and dynamically select an accurate model size. We revise a previously proposed localized forgetting approach for the NGnet and adapt some unit manipulation mechanisms to it for dynamic model selection. The mechanisms are improved for more robustness in negative interference prone environments, and a new merge manipulation is considered to deal with model redundancies. The effectiveness of the proposed method is compared with the previous localized forgetting approach and an established learning method for the NGnet. Several experiments are conducted for a function approximation and chaotic time series forecasting task. The proposed approach possesses robust and favorable performance in different learning situations over all testbeds.\",\n \"Title: OFDM Visible Light Communication using Off-the-shelf Video Camera\\nYear: 2017\\n\\nAbstract: This paper describes a rapid and flicker-free visible light communication technique that uses an off-the-shelf video camera. Transfer rates at least 53% faster than existing methods were achieved in experiments. Features of the proposed method are discussed via theoretical analysis.\",\n \"Title: Selective Visible Light Communication for Multiple Video Cameras using a Single Light Source.\\nYear: 2018\\n\\nAbstract: In this paper, we propose a selective visible light communication method using a single light source and multiple video cameras by using their differences in reception sensitivity between carrier waves composed of OFDM signals. In our evaluation experiments, the transmitted signals were composed of 50th, 75th, 78th, and 80th order carrier waves encoding symbols modulated by 4, 8, and 16 PSK. The exposure time ratio for each camera was set to different values so that symbols encoded in one of the carrier waves could be decoded successfully, but erroneously in the other waves. The selectivity of individual carrier waves as theoretically derived was confirmed through the experimental results.\",\n \"Title: Indoor Positioning Using Reflected Light and a Video Camera\\nYear: 2018\\n\\nAbstract: This paper describes an indoor positioning technique using a video camera that captures LED light reflected by the floor. Indoor positioning for mobile devices can be very useful. In particular, localization techniques using LEDs and cameras, so-called visible light positioning, are known to be effective and have high accuracy. However, existing methods have the constraint that they must capture the light source directly. This requires a high-performance processor and a high-resolution image. However, light sources cannot always be detected directly (loss of signal: LOS). Our proposal aims to solve these problems by estimating the position of a camera that does not face the light directly but monitors light reflected by the floor. Specifically, individual LED ceiling lights emit sinusoidal waves modulated with different frequencies, and the camera captures the overlapped light from the LEDs reflected by the floor then demodulates the signal. The camera need not seek the ceiling lights directly from an image, unlike existing methods. The position can be estimated using any part of the image because usually the ceiling light is reflected by the whole floor. Experimental results show that the proposal requires less than 1/100 as many pixels for localization as existing methods and the position can be estimated within 0.4 m at the 90th percentile in a 2.5 m square room. We show that the cause of errors is mainly the difference between the LED diffusion model and the actual light diffusion, the occlusion and the noise and movement of the camera. Overcoming these problems remains as our future work.\",\n \"Title: Smartphone Localization Using Active-Passive Acoustic Sensing\\nYear: 2018\\n\\nAbstract: In this paper, we describe a novel position-recognition method that uses passive acoustic signals from two previously installed speakers (passive acoustic sensing) and active acoustic signals from a smartphone's loudspeakers (active acoustic sensing). In passive acoustic sensing, a locus of positions for the smartphone can be calculated from the measured time difference of arrival from the two installed speakers. In active acoustic sensing, a chirp signal is transmitted from the speakers of the smartphone, and the distance to the side wall is measured from the propagation time of arrival at its microphone. We can obtain the smartphone position from our proposed model equations by combining these two results. In our experiments, we installed speakers at intervals of 10 m along a corridor and estimated the smartphone position at several places. From these results, we obtained 90th percentile errors of less than 0.224 m for 2-D positioning. We found that multipaths from the side wall were causing the positioning error in passive acoustic sensing, and the variance of the positioning error using the top microphone which was omnidirectional was smaller than the bottom one. When we introduced a weighting based on the result of the active acoustic sensing and the difference in the performance between microphones, the 90th percentile errors were reduced to less than 0.134 m.\",\n \"Title: Novel Application Of Spherical Microphone Array Sensor With Three-Dimensional Directivity For Home And Office Environments\\nYear: 2015\\n\\nAbstract: Interest in sound interfaces is increasing because such interfaces do not need advanced knowledge about particular devices, nor do they require physical operation. However, such interfaces are difficult to use because the general living environment often contains background noise. In order to solve this problem, sound separation systems that use a microphone array sensor have been proposed. In previous work, this microphone array sensor was a small system that considered only two-dimensional (2-D) directivity control. In this paper, we present the design of a spherical microphone array sensor with 3D directivity. This 3-D directivity property is confirmed via an experimental evaluation.\",\n \"Title: Novel application of a range image sensor to eye gaze estimation by using the relationship between face and eye directions\\nYear: 2015\\n\\nAbstract: In this study, we estimate gaze direction using the relationship between the face and eyes. The face and eyes are divided laterally and in lengthwise direction. We set up an object laterally and in lengthwise direction and measured the face angle using a Kinect sensor, which is range image sensor, when gazing at an object. The angle of the eyes is fixed at the angle of the object and grasp of the relationship between face and eyes. We calculate the gaze direction using the relation between the face and eyes. Then, the results of present experiment, if based on relationship between face and eyes, has been shown to be effective though the results of the experiment.\",\n \"Title: Electrodermal activity based study on the relationship between visual attention and eye blink\\nYear: 2015\\n\\nAbstract: In this paper, the relationship between visual attention and eye blinking is described. In our experiment, we observed blinking when a subject performed a task. We determined that the subjectu0027s visual attention functions during the task by electrodermal activity. Experimental results showed that blink rate decreased when the subjectu0027s visual attention was engaged. On the other hand, blink rate increased when the subjectu0027s visual attention shifted from attentive to inattentive. These findings enable a more objective evaluation of the relationship between visual attention and blinking when determining by electrodermal activity whether visual attention is engaged.\",\n \"Title: Novel application of Kinect sensor to support immersive learning within museum for children\\nYear: 2015\\n\\nAbstract: This paper presents a system to support learning within museum for children as a novel application of Kinect based human sensing system. The system measures the physical movement of the learner using a Kinect sensor, and provides a sense of immersion in the paleontological environment by adapting the surroundings according to these movements. As the first stage of this project, we have developed a prototype system that allows learners to experience the paleontological environment. Here, we evaluated the performance of the sensor of BESIDE in order to confirm whether or not this system can put into practice BESIDE at the museum. This paper summarizes the current system and describes the evaluation results.\",\n \"Title: Poster: Multicamera Synchronization for Smartphones using Optimally Modulated Illuminations.\\nYear: 2017\\n\\nAbstract: The paper describes a rapid and accurate time-synchronization technique for smartphones using their built-in cameras and its preliminary evaluations for application development.\",\n \"Title: Novel application of 3D range image sensor for estimation of interests based on fixation time of face orientation\\nYear: 2017\\n\\nAbstract: In this paper, we describe the relationship between the presence or absence of interest and the fixation time of face orientation. There is a conventional method of measuring the fixation time of line-of-sight orientation to prevent accidents due to carelessness. In addition, studies are being performed on the estimation of the relationship between face orientation and line-of-sight orientation. However, even if face and line-of-sight remain, it has not been confirmed whether people are interested. Therefore, we conducted experiments to investigate the relationship between the presence or absence of interest and the fixation time of face orientation. We simultaneously measured the change in interest and face orientation with time as subjects watched two movies. As a result, it was suggested that face orientation remained longer for an object of interest.\",\n \"Title: Accuracy evaluation of hand motion measurement using 3D range image sensor\\nYear: 2017\\n\\nAbstract: Techniques capable of measuring hand motion are expected to be applied in various situations. Examples are the practice support systems used in activities such as sport and dance, for instance, the system employed in baseball pitching form analysis. This analysis evaluates the state of the throwing form numerically and visually by measuring the velocity and trajectory of the hand. This requires measurement of the hand by a sensor and is accomplished by using a motion capture system as the method for measuring hand motion with high accuracy. However, it is time consuming to prepare the system. Therefore, a 3D range image sensor, which is inexpensive and easy to prepare, is proposed. However, as the actual measurement accuracy of this sensor is unknown, it was evaluated by calculating the error with the measured value of motion capture as the true value. In this research, we calculated the error between the 3D coordinates and velocity to evaluate the error. As a result, the effectiveness of the measurement accuracy of the hand motion by the 3D range image sensor was confirmed. The results suggest that the 3D range image sensor can be used in various situations involving human activity.\",\n \"Title: Novel application of microphone array sensor for children's language learning support — Intelligent Interactive Design using voice separation and recognition system —\\nYear: 2015\\n\\nAbstract: Development of a robust and precise voice interface could accelerate the realization of a learning support system that utilizes voice. In our research, this objective is called Intelligent Interactive Design of learning support. In order to realize Intelligent Interactive Design, we propose a “voice separation and recognition system” that aims at clear voice separation for robust voice recognition by voice recognition systems. The results of experiments conducted indicate that our Intelligent Interactive Design has a correct voice recognition rate above 70%. The results are highly satisfactory and indicate that Intelligent Interactive Design can be realized via our proposed system in the near future.\",\n \"Title: EDA Sensor-based Evaluation of a Vegetation Succession Learning System\\nYear: 2018\\n\\nAbstract: There are many forest problems that need to be solved to move toward a sustainable society; therefore, educating people, especially children, about forest problems is very important. Although schools conventionally educate children through textbooks, children are not expected to learn about forest problems actively from only textbooks. Therefore, this study develops game-type learning material that enables students learn complex mechanisms of vegetation succession and the actual state of succession, while taking interest in forest problems, by performing forest management themselves. For evaluation of the system, we measure the electrodermal activity (EDA) because using a conventional questionnaire can only qualitatively evaluate whether learning using the system is more interesting than when using text. EDA sensors are used to measure physiological response of participants reading texts and those using the system; the interest when using the system is evaluated quantitatively. The experiment shows that the change of EDA increases when using the system, which suggests that using the system is more interesting and can be better for learning than reading text.\",\n \"Title: Detecting Text in Manga Using Stroke Width Transform\\nYear: 2019\\n\\nAbstract: The Japanese comic-book style known as manga is becoming a popular topic for researchers. This paper focuses on the problem of detecting text regions in manga pages. Because it is time-consuming and laborious to identify the text regions in images manually, an automatic approach is highly desirable. Here, we propose a new text-detection method for manga using a Stroke Width Transform (SWT) technique in conjunction with a Support Vector Machine (SVM). Conventional SWT-based text-detection techniques perform poorly with manga because both text and non-text objects have similar characteristics for strokes, lines, and shapes. To better suit manga, we propose modifying the rules for finding letter candidates, which improves the ability to capture text. An SVM is then used to classify image patches into letter and nonletter regions. We compared our proposed framework with a conventional framework and other text-detection methods including deep-learning techniques. In the results, our proposed method achieved the highest F-measure of 0.506.\",\n \"Title: Illegal Photograph Detection under Modulated LED Illumination\\nYear: 2019\\n\\nAbstract: Nowadays, almost everyone has a smartphone and can easily take pictures. Consequently, illegal acts such as photographing or video-recording copyrighted works and uploading them to the internet are reported as a growing problem in our society. This paper proposes a method for detecting such illegal photography. By illuminating copyrighted works with an LED light emitting orthogonal frequency division multiplexing multi-carrier signals and utilizing the feature of exposure time ratio in a rolling shutter camera, it is possible to distinguish between photographs taken by authorized and unauthorized cameras. The evaluation experiments confirmed that the proposed method could correctly identify photographs taken by authorized and unauthorized cameras.\",\n \"Title: Device-Free Handwritten Character Recognition Method Using Acoustic Signal\\nYear: 2021\\n\\nAbstract: In this paper, we propose a method for recognizing handwritten characters by a finger using acoustic signals. This method is carried out using a smartphone placed on a flat surface, such as a desk. Specifically, this method uses an ultrasonic wave transmitted from the smartphone, which is reflected by the finger, and an audible sound is generated when writing a handwritten character. The proposed method does not require an additional device for handwritten character recognition because it uses the microphone/speaker built into the device. Evaluation results showed that it was able to recognize 36 types of characters with an average accuracy of 77.8% in a low noise environment for 10 subjects. In addition, it was verified that combining an audible sound and an ultrasonic wave in this method achieved higher recognition accuracy than when only an audible sound or an ultrasonic wave was used.\",\n \"Title: Short-Time and Adaptive Controllable Spot Communication Using COTS Speaker\\nYear: 2021\\n\\nAbstract: This paper proposes a spot-communication method that can direct the spot to the user location adaptively. In the proposed method, the first transmitted signals are used to estimate user location, which is then reflected in the second transmitted signals; therefore, the spot directed to the user can be generated instantaneously. As the signals consist of mutually orthogonal sinusoidal waves, multip...\",\n \"Title: Indoor Localization Method For a Microphone Using a Single Speaker\\nYear: 2021\\n\\nAbstract: In this paper, we propose a 2D localization method using a single speaker and a microphone. Our proposed method estimates the direction of the microphone based on the knowledge that the spectral amplitude of a speaker in each direction is different. Additionally, the distance between the speaker and microphone is estimated based on the received amplitude. The 2D location of the microphone is calcu...\",\n \"Title: NL-Beep: A Ranging System between Multiple Smartphones Using Acoustic Sensing in NLOS Environments\\nYear: 2021\\n\\nAbstract: In this paper, we describe NL-Beep, which is a novel ranging method between multiple smartphones using acoustic sensing in non-line-of-sight (NLOS) environments. We need to know the distance between people to maintain social distancing because of the COVID-19 pandemic. Acoustic-based ranging methods that use a smartphone built-in speaker and microphone represent one approach to high-accuracy rangi...\",\n \"Title: Smartphone Positioning Using an Ambient Light Sensor and Reflected Visible Light\\nYear: 2021\\n\\nAbstract: In this paper, we propose a method for the 2D positioning of a smartphone by receiving sinusoidally modulated light signals emitted by ceiling-mounted LEDs. An ambient light sensor (ALS) mounted on the smartphone measures the reflected illumination from the floor. The advantage of this combination is that it consumes very little power, does not require the implementation of additional devices, and...\",\n \"Title: Expanding the Positioning Area for Acoustic Localization Using COTS Mobile Devices\\nYear: 2021\\n\\nAbstract: In this paper, we propose a novel acoustic localization system using commercial off-the-shelf (COTS) mobile devices. Acoustic-based systems have advantages in terms of accuracy and cost. However, the measurable positioning area is limited because of the signal attenuation and the poor performance of microphones embedded in COTS mobile devices. Our system leverages a transmission scheme that combines time-division multiple-access (TDMA) and frequency-division multiple-access (FDMA) techniques to address the limitation. In the proposed approach, each speaker transmits different band chirps in a predefined sequence to mitigate multiple-access interference. A COTS device receives modulated signals via a built-in microphone. We exploit the received signals and estimate the position by calculating time difference of arrival (TDoA). We were able to reduce the error to a 90th-percentile error of 46.26 cm at a measurement point that could not be estimated by FDMA-based positioning. The experiment results show that our system is more accurate and has a larger area of positioning capability compared with FDMA-based positioning.\",\n \"Title: A Localization Method Using Reflected Luminance Distribution\\nYear: 2021\\n\\nAbstract: Visible light positioning is expected to become an effective means of indoor localization, but most existing methods require the capture of direct light, which is a significant limitation. In this paper, we propose a novel localization method based on received signal strength, which does not need to use direct light signals but instead uses reflected light from the floor. Our method is based on two observations. First, assuming a flat floor, the reflected light from the light source decays according to a gradient model whose peak is just below the light source. Second, the decay can be estimated effectively even for a floor surface several meters away from the light source. Inspired by these observations, we propose a method for estimating the coordinates of the floor surface and the two-dimensional coordinates of the light receiver (a camera). The method uses pattern matching within the distribution of signal decay measurements obtained via photographs of an arbitrary floor surface. Although the proposed method is vulnerable to shadow effects such as those caused by the camera tripod used in our experiments, we achieved a 90th percentile of less than 32 cm in our offline experiments. After removing the tripod shadows from the captured video manually, the same technique achieved a 90th percentile of 22 cm. To investigate the efficiency of the pattern matching, we also conducted experiments on the relationship between pixel utilization and localization results. In this paper, we also discuss camera posture estimation and power consumption issues.\",\n \"Title: RefRec plus : Six Degree-of-Freedom Estimation for Smartphone Using Floor Reflecting Light\\nYear: 2022\\n\\nAbstract: This paper describes a novel visible light positioning (VLP) system called RefRec+ allowing to estimate the six degree-of-freedom (6DoF) of a smartphone. In most existing VLP systems, their front camera faces multiple light sources installed at different places on a ceiling to detect their direct signals. To overcome the problem of the limited field of views that causes failure to capture required numbers of light sources for positioning and that of the high computational complexity because of image processing to a large-sized pixel data, RefRec+ captures indirect lights from the light sources reflected via a floor. RefRec+ estimates the 2-D position of a point of interest (POI) by calculating the received signal strength of individual light sources using the floor image captured by the camera. Using 2-D positions of multiple POIs and the angle of arrival method, RefRec+ obtains the 6DoF of the smartphone. Several experiments to confirm the performance of RefRec+ were conducted. Experimental results in a room measuring 4.0 m x 4.0 m using nine POIs each of which consists of 32 x 32 pixels in a captured image showed that the absolute errors at the 90th percentile for the 3-D coordinates were 0.2073 m, 0.1713 m, and 0.002464 m along the X, Y, and Z axes, respectively, and for the pitch, roll, and yaw angles were 5.78, 5.69 and 3.96 degrees, respectively.\",\n \"Title: PT-Sync: COTS Speaker-based Pseudo Time Synchronization for Acoustic Indoor Positioning\\nYear: 2022\\n\\nAbstract: Positioning with a small number of anchors is an important issue in the study of acoustic indoor positioning systems (AIPS). We present PT-Sync, a novel approach to time-synchronize between a commercial off-the-shelf (COTS) speaker and a mobile device by leveraging acoustic sensing and reflected signals from the floor. PT-Sync enables ranging with one speaker and 2-D positioning with two speakers without any additional hardware. Our proposed time synchronization method requires height information from the floor in the calculation process, which we estimate by active acoustic sensing. Using a unique averaging technique and IMU enables robust height estimation. PT-Sync can be used in a variety of indoor environments and can be time-synchronized with already installed speakers. The results of the evaluation experiment confirmed that a synchronization error of 0.16 ms was achieved even at a distance of 6 m from the speaker, and that synchronization on the order of microseconds could be achieved. Furthermore, pedestrian tracking experiments confirmed that positioning of less than 38.9 cm can be achieved at the 90th percentile.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":128,"string":"128"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13362,"string":"13,362"}}},{"rowIdx":13363,"cells":{"question_id":{"kind":"string","value":"Ignacio Aedo"},"question":{"kind":"string","value":"Generate an abstract for the title \"Designing and implementing interactive and realistic augmented reality experiences\" using the following items: Approach, Augmented Reality, Realistic, Model-based, Feasibility."},"answer":{"kind":"string","value":"In this paper, we propose an approach for supporting the design and implementation of interactive and realistic Augmented Reality (AR). Despite the advances in AR technology, most software applications still fail to support AR experiences where virtual objects appear as merged into the real setting. To alleviate this situation, we propose to combine the use of model-based AR techniques with the advantages of current game engines to develop AR scenes in which the virtual objects collide, are occluded, project shadows and, in general, are integrated into the augmented environment more realistically. To evaluate the feasibility of the proposed approach, we extended an existing game platform named GREP to enhance it with AR capacities. The realism of the AR experiences produced with the software was assessed in an event in which more than 100 people played two AR games simultaneously."},"correct_answer":{"kind":"string","value":"In this paper, we propose an approach for supporting the design and implementation of interactive and realistic Augmented Reality (AR). Despite the advances in AR technology, most software applications still fail to support AR experiences where virtual objects appear as merged into the real setting. To alleviate this situation, we propose to combine the use of model-based AR techniques with the advantages of current game engines to develop AR scenes in which the virtual objects collide, are occluded, project shadows and, in general, are integrated into the augmented environment more realistically. To evaluate the feasibility of the proposed approach, we extended an existing game platform named GREP to enhance it with AR capacities. The realism of the AR experiences produced with the software was assessed in an event in which more than 100 people played two AR games simultaneously."},"documents":{"kind":"list like","value":["Title: Hci for emergencies\nYear: 2008\n\nAbstract: Emergencies put people in a particular state of mind and often also in difficult physical situations. When de-signing information technology for emergencies, these two sides have to be taken into account in the various activities supporting design. This includes studying and understanding the users and the influential factors for good designs, engaging the users in the design process as well as evaluating designs in realistic ways. There are challenges specific to emergencies in all of these activities, as well as in new technologies ranging from wearable computing to distributed information systems. This workshop is meant as an opportunity for interdis-ciplinary discussion as well as practical hands-on ex-change of experiences regarding these challenges. The goal is to work towards a better understanding of the challenges, technologies, practices, and design meth-odologies relevant to HCI in emergencies.","Title: Modeling the Dynamic Behavior of Hypermedia Applications\nYear: 2001\n\nAbstract: Hypermedia applications can be defined as collections of interactive and multimedia documents that are organized as a hypertext net. The development of hypermedia applications poses specific problems, such as the need for modeling sophisticated navigational structures, interactive behaviors, and harmonic presentations involving the synchronization of contents. Moreover, the increasing popularity of Internet-based systems has put stress on the lack of mechanisms to formally specify security policies when designing hypermedia applications. Traditional design models and methodologies are not suitable for hypermedia applications and the up-to-now developed hypermedia-oriented models do not cover the whole set of design needs. In this context, we present Labyrinth, a hypermedia-oriented model providing formal elements to describe the static structure and dynamic behavior of this kind of nonlinear, multisensory, and interactive applications.","Title: A Methodological Approach to Encourage the Service-Oriented Learning Systems Development.\nYear: 2009\n\nAbstract: The basic idea of service-oriented learning is that a learning environment should be conceived as a set of independent units of learning packaged as learning services. The design, development and deployment of a learning system based on integrating different learning services needs both a technological platform to support the system as well as a methodology that manages the development process. Such technological platform is provided by the Service-Oriented Learning Architecture (SOLA). SOLA proposes an architecture style, which defines how to deploy several units of packeged-learning services. The purpose of this paper is to review the SOLA concept and to present a specific method based on specifying instructional domains, to complement the SOLA approach. Our method suggests the definition of a feature model, which represents the characteristics of the instructional domain, in order to address the identification and clasiffication of candidate services. The approach here proposed facilitates the definition of candidate-learning services in order to enhance the integration of such services.","Title: Towards efficient web engineering approaches through flexible process models\nYear: 2007\n\nAbstract: After more than a decade of web developments and some deafening fiascos, it has become clear that it is not possible to face the development of large scale web systems without following a systematic and well-defined process to guarantee quality, measurability, maintainability and reusability. There are a number of hypermedia/web engineering methods that provide mechanisms to specify the product requirements, including those concerning structure, navigation, interaction, presentation and access. But apart from product requirements there are also process requirements which in the web arena are constantly changing. Hence, to be put in practice without disturbing the project goals nor compromising its success, methods have to rely on empirical and flexible process models that can be easily adapted to fit process requirements. Little attention has been paid to the process model in most hypermedia/web methods which usually apply a classical iterative process based on the use of prototypes that are tested with users. In this paper we describe how we did apply the ADM web engineering method following a flexible star life cycle in the context of a specific web project highlighting the main benefits of this approach. In particular we will describe the different cycles applied in the ARCE project, illustrating the application of a usability engineering life cycle in a real case.","Title: A Literature-Based Approach To Annotation And Browsing Of Web Resources\nYear: 2003\n\nAbstract: The emerging Semantic Web technologies critically depend on the availability of shared knowledge representations called ontologies, which are intended to encode consensual knowledge about specific domains; Currently, the proposed processes for building and maintaining those ontologies entail the joint effort of groups of representative domain experts, which can be expensive in terms of co-ordination and in terms of time to reach consensus. In this paper, literature-based ontologies, which can be initially developed by a single expert and maintained continuously; are proposed as preliminary alternatives to group-generated domain ontologies, or as early versions of them. These ontologies encode domain knowledge in the form of terms and relations along with the (formal or informal) bibliographical resources that define or deal with them, which makes them specially useful for domains in which a common terminology or jargon is not soundly established. A general-purpose metamodelling framework for literature-based ontologies - which has been used in two concrete domains - is described, along with a proposed methodology and a specific resource annotation approach. In addition, the implementation of a RDF-based Web resource browser - that uses the ontologies to guide the user in the exploration of a corpus of digital resources- is presented as a proof of concept.","Title: Meta-design blueprints: principles and guidelines for co-design in virtual environments\nYear: 2011\n\nAbstract: Meta-design is defined as a conceptual framework that allows endusers to create contents by using socio-technological infrastructures in which people can actively participate. Despite the fact that the foundations for metadesign are well known, it is still an abstract concept lacking of suitable design artifacts to guide its application. The aim of this paper is to analyze the concept of meta-design in order to define blueprints for its application in web-based environments. Based on a review of both literature and websites conceived to design contents by users, the paper compiles a number of guidelines to address the development of web tools that support meta-design.","Title: Light on horizontal interactive surfaces: Input space for tabletop computing\nYear: 2014\n\nAbstract: In the last 25 years we have witnessed the rise and growth of interactive tabletop research, both in academic and in industrial settings. The rising demand for the digital support of human activities motivated the need to bring computational power to table surfaces. In this article, we review the state of the art of tabletop computing, highlighting core aspects that frame the input space of interactive tabletops: (a) developments in hardware technologies that have caused the proliferation of interactive horizontal surfaces and (b) issues related to new classes of interaction modalities (multitouch, tangible, and touchless). A classification is presented that aims to give a detailed view of the current development of this research area and define opportunities and challenges for novel touch- and gesture-based interactions between the human and the surrounding computational environment.","Title: Integrating RBAC Mechanisms in a Web Server\nYear: 2003\n\nAbstract: ABSTRACT Hypermedia systems (whether web sites or not) should support multilevel policiesm, offering different views and manipulation abilities of the same information to users with different needs in a particular context. Several experiences have demonstrated that role-based access control (RBAC) policies are a powerful mechanism to simplify management tasks. This paper describes the implementation and the integration in the Apache server of the MARAH model, that provides security designers with mechanisms to specify security rules using elements and abstractions of the hypermedia domain (such as nodes, links or contents), considering a web site as a special case of hypermedia. KEYWORDS Hypermedia, security models, role-based access control, web server. 1. INTRODUCTION Hypermedia systems should support multilevel policies in order to offer different views and manipulation abilities of the same information to users with different needs and responsibilities in a particular context [Diaz01]. The assignment of authorizations in terms of users or groups is a unmanageable, laborious and prone to error task, so that role based access control (RBAC) appears as an useful approach to simplify this management [Ferraiolo92], [Sandhu96]. RBAC is a security mechanism that regulate access to resources through organizational entities called roles [Jansen98]. High-level security models make possible to specify the rules that control the access to a specific system, but this specification can be faced from rather different levels of abstraction. MARAH (Role-Based Access Model for Hypermedial Architectures in Spanish) is a high level security model for hypermedia, that tries to fill in the conceptual gap between the application domain and the underlying hypermedia platform (e.g. web) that supports it. MARAH considers three layers in the hypermedia application security design. The top one is called","Title: Un servicio web de políticas de acceso basadas en roles para hipermedia\nYear: 2005\n\nAbstract: High level security is a key requirement in hypermedia/web applications. The systems opening to the Internet makes the research effort to move towards protecting the information transmission (i.e. SOAP messages, policy descriptions,…), but little attention is paid to what the user can do with the system. Role-based access control (RBAC) allows to formulate the organization's resource access policy...","Title: Designing the Execution of Learning Activities in Complex Learning Processes Using LPCEL\nYear: 2006\n\nAbstract: The contemporary education has begun to observe constructivist position as important in understanding diversity in education. Instructional design on technology (IDT) presents important challenges to integrate principles, models and techniques inspired by this new perspective emerging in educational technology. The complex learning process (CLP) is a vision that can be suitable to facilitate this aim. In order to face these challenges, it is essential to integrate new technology-supported learning. Our vision is focused on the development of learning process composition and execution languages (LPCEL), which can facilitate the design, composition and execution of CLP. This work presents an overview of LPCEL specification, so that it can be a reference for the development of related technologies.","Title: Towards an effective evaluation framework for IMS LD-based didactic materials: criteria and measures\nYear: 2007\n\nAbstract: Evaluation is one of the most important activities in the didactic materials development process since it allows developers to check if the obtained material satisfies all requirements and it also provides developers with reliable information about material's utility, validating if the obtained material can be effective support in the achievement of the educational goals which it intends to support. Evaluation results provide valuable information for the material redesign in such cases when the requirements or educational goals are not satisfied. Nevertheless its importance, the evaluation has been often neglected in most of the approaches related to the development of didactic materials, which are more focused on issues such as interoperability or reusability. In this paper we present the MD2 evaluation framework based on a general evaluation procedure that include a set of criteria and measures for the two more important evaluation objectives of IMS LD-based didactic material: its usability and pedagogical usefulness.","Title: Meeting the needs of teachers and students within the CESAR training system\nYear: 1998\n\nAbstract: Computers seem to be an unquestionably useful tool to support the learning process, although positive students' and teachers' attitude towards the system is required to guarantee a successful introduction of new technologies in traditional classrooms, Training or exercises provide the students with the challenge of using their knowledge to solve concrete problems, so that they incite students to participate actively, Training can be adapted to different learning styles in order to strengthen student involvement. Moreover, tools to adapt the didactic material to several educational methods must be provided, in such a way that teachers consider the system a helpful tool rather than a substitute, Taking into account the foregoing, this paper describes a training system to create and use exercises in a hypermedia learning environment for hearing-impaired children called CESAR.","Title: Agent-based adaptive selection and interaction to Z39.50 servers\nYear: 2000\n\nAbstract: Digital libraries and OPACs offer an enormous collection of information resources which can be accessed through the Internet by quite different users thanks to the existence of standard protocols for information retrieval such as Z39.50. However, some users may have difficulty in getting the items they are looking for in such a huge volume of heterogeneous resources since they have to know where and how they have to search. Thus, one of the main reasons for disregarding the Z39.50 service has traditionally been the absence of appropriate interfaces and the cost of making alternative searches. WAY-Z39.50 tries to help spread the use of these servers by providing easy Web access to them, as well as facilitating access to multiple servers at once. The prototype implements the general WAY model based on an agent-based architecture that provides adaptive searching in different servers using an adaptive interface as well","Title: ECCE toolkit: prototyping UbiComp device ecologies\nYear: 2014\n\nAbstract: The tremendous amount of different input devices and interactive environments envisioned by researchers produces a severe challenge for the development of ubiquitous interaction. Toolkits that support the rapid setup of ubiquitous environments reduce the effort in arranging the technological medium and have the potential to lower prerequisite knowledge and automate low-level programming tasks. In this paper, we present our work-in-progress approach: a toolkit that combines physical and digital components into a unique environment to allow the rapid setup of device ecologies.","Title: Generation of Personalized Web Courses Using RBAC\nYear: 2002\n\nAbstract: Role-based access control policies model the users domain by means of complex structures where the roles assumed by the users are specialized into more concrete subroles which inherit properties and authorizations from their parents. In this paper, we describe how to combine these principles and adaptation to provide personalized access to the different types of users of a web-based course. We also present Courba, a platform that generates personalized web-based courses using XML to support the definition of access policies.","Title: Validation of critical parameters for predictive evaluation of notification system in avionics interfaces\nYear: 2007\n\nAbstract: The evaluation of notification systems is rare in critical systems. The only available experiences are based on empirical data on costly simulated environments and the subjective follow-up of some guidebooks probed by the experience. In case of absence of performance requirements, critical parameters can provide quantitative measures that may be used to determine the overall usability of interfaces that continuously present precious information (id est. Notification Systems) in Avionics (NSA) and should be validated before use to improve the confidence level in the measurement unit. In this paper, we introduce a set of critical parameters that could be used for usability evaluation of NSA's interfaces. A process for a formal validation is described and results of the applicability of these parameters to the real NSA interface of A400M's power plant are presented.","Title: Labyrinth, an abstract model for hypermedia applications. Description of its static components\nYear: 1997\n\nAbstract: In information technology, models are abstract devices to represent the components and functions of software applications. When a model is general and consistent, it represents a useful design tool to unambiguously describe the application. Traditional models are not suitable for the design of hypermedia systems and, therefore, specific design models and methodologies are needed. In the present article, the requirements for such models are analysed, an overview of the characteristics of the existing models for hypermedia applications is made and an abstract model fulfilling the analysed requirements is presented. The model, called Labyrinth, allows 1) the design of platform-independent hypermedia applications; 2) the categorisation, generalisation and abstraction of sparse unstructured heterogeneous information in multiple and interconnected levels; 3) the creation of personalisations (personal views) in multiuser hyperdocuments for both groups and individual users and 4) the design of advanced security mechanisms for hypermedia applications.","Title: Uses of Augmented Reality for Supporting Educational Presentations\nYear: 2013\n\nAbstract: This work aims to explore the benefits and potential uses of Augmented Reality technology for supporting communication in lectures and presentations. In this paper we present the architecture and implementation of an Augmented Presentation Feedback System (APFs). The system allows a speaker equipped with an Augmented Reality Head-Mounted Display to visualize visual cues depicted over the listeners' heads. These can be used as a way of providing the speaker with continuous, private and immediate feedback on her explanations, so she can adapt the content and pace of the explanation to the specific needs of the listener and improve the flow of the presentation.","Title: A design toolkit for hypermedia applications\nYear: 2003\n\nAbstract: The development process of hypermedia applications involves a variety of users with different levels of knowledge and skills. In order to get a good communication among participants, a graphical toolkit based on a method facilitates this work. In this paper, we present a design environment, Ariadne Tool, that allows a designer to model a hypermedia application, to validate such a design and to generate dynamically XML + SMIL implementation templates. This environment is based upon the Ariadne Method which offers a set of integrated activities to model hypermedia applications in a systematic and iterative way.","Title: Evaluation of Hypermedia Educational Systems: Criteria and Imperfect Measures\nYear: 2002\n\nAbstract: Educational systems have to be assessed to determine whether their user interface, didactic method, instructional materials and interaction mechanisms help users reach their learning and teaching goals. With this purpose, educational developers need to rely on a set of clear, concrete and measurable quality criteria. In this paper, we propose an evaluation framework made up of a number of criteria to test the utility and usability of educational hypermedia systems. We also discuss that measuring these criteria entails different forms of imprecision and uncertainty, that call for the user of representation formalisms like fuzzy set theory. Theframework presented here is aimed not only at helping educational developers to evaluate their systems, but also to provide them with some guidance to address educational requirements during the design process.","Title: Achieving shared understanding in face-to-face 'tabletop' exercises\nYear: 2013\n\nAbstract: Shared understanding plays a key role within the emergency-planning context to successfully develop planning tasks. Particularly in 'tabletop' exercises, such an understanding is required to make decisions about planning. However, as the task progresses, the amount of relevant knowledge that a planner can remember about the task progressively decreases. This fact can impose a limit on the task progress. With the purpose of overcoming such a limitation, this work presents a computer-based face-to-face collaborative tool aimed at supporting 'tabletop' exercises.","Title: Ariadne, a Development Method for Hypermedia\nYear: 2001\n\nAbstract: Hypermedia development poses very specific problems such as the need for mechanisms to model sophisticated navigational structures, interactive behaviours and usable multimedia compositions. Moreover, since the majority of hypermedia applications are accessed by different users, security becomes a key feature. In this context, we present a development method called Ariadne which offers a number of tools to create hypermedia applications in an progressive and integrated way.","Title: Toward Hypermedia Design Methods for the Semantic Web\nYear: 2003\n\nAbstract: Hypermedia design methods have been proposed for thedevelopment of hypermedia and web applications. Nowadays,we face up to another challenge, the Semantic Web,in order to represent web resources in a structured, logicaland semantic way. Therefore, hypermedia design methodswill have to provide semantic contents and contextual informationabout application domain during the developmentprocess of web applications. In this paper, we propose toaccomplish that including ontologies within the conceptualmodeling of hypermedia applications.","Title: SocialStory: a social storyboard system for sharing experiences in emergencies\nYear: 2012\n\nAbstract: During and after crisis situations people are interested in getting knowledge about what happened and in obtaining information regarding damages, victims, and possible repercussions. Social network systems represent powerful sources due to their rapid growth in the last few years and the amount of continuous updated information published by people. Studies confirmed that people are interested in reporting facts during hazards, however due to the wide distribution of information and the lack of mechanisms to re-use it, it is an awkward task to be accomplished. For the above reasons in this paper we present SocialStory, a social platform for helping people to retrieve and filter materials available on the Internet and to compose and share personal experiences about crisis situations.","Title: End-user oriented strategies to facilitate multi-organizational adoption of emergency management information systems\nYear: 2010\n\nAbstract: Response to large-scale emergencies is a cooperative process that requires the active and coordinated participation of a variety of functionally independent agencies operating in adjacent regions. In practice, this essential cooperation is sometimes not attained or is reduced due to poor information sharing, non-fluent communication flows, and lack of coordination. We report an empirical study of IT-mediated cooperation among Spanish response agencies and we describe the challenges of adoption, information sharing, communication flows, and coordination among agencies that do not share a unity of command. We analyze three strategies aimed at supporting acceptance and surmounting political, organizational and personal distrust or skepticism: participatory design, advanced collaborative tools inducing cognitive absorption, and end-user communities of practice.","Title: A semantic representation for domain-specific patterns\nYear: 2004\n\nAbstract: Design patterns are a valuable mechanism to capture and disseminate best practice in software design. The oft-cited definition of an Alexandrian pattern, “a solution to a problem in a context”, stimulates the definition of patterns from knowledge and expertise in any domain. Indeed, their application has spread from the object-oriented community, who first adopted them, through different software areas including human-computer interaction, virtual environments, ubiquitous computing, hypermedia and web engineering. This kind of patterns that describe successful solutions to recurring design problems in terms of a specific domain of application are known as domain-specific patterns. The increasing number of available design patterns is making difficult to find the most appropriate one given a specific problem since this task requires mastery on existing design patterns. Hence, there is a need to introduce a formalism to describe them accurately and to allow a rigorous reasoning process to assist users to retrieve those patterns that solve their problems. With this purpose, we propose a semantic representation for domain-specific patterns based on the domain knowledge for which they were written and for which an ontology-based approach is applied. This representation is used as an underlying armature for complementing the informal textual pattern description by means of semantic annotations. The combination of the literary pattern representation with its formal representation counterpart could assist an intelligent search engine that supports users not just for retrieval purposes but also for the discovery useful design solutions improving, therefore, their ability to develop quality software.","Title: Making Semantic Web based-hypermedia Applications\nYear: 2005\n\nAbstract: The existence of web pages that are described semanti- cally via ontologies and metadata conforming to these on- tologies is crucial to bring the Semantic Web to life. In this paper we address the problem of developing semantic web- based hypermedia applications through web-hypermedia design methods. For that, we propose a general approach based on extracting an ontology-based design from a tra- ditional model-driven design , thus allowing hypermedia designers to obtain both domain ontologies and annotated documents in parallel with the application design without requiring extra tasks and expert know-how. This approach is presented through a specific hypermedia design method called Ariadne Development Method (ADM) and its soft- ware tool, AriadneTool, that automates a semantic extrac- tion process to provide annotated documents in a format suitable for the semantic web, as RDFS and RDF. Moreover, a semantic web platform has been developed in order to enable the publication of the resulting semantic web-based hypermedia application.","Title: MUTO: the modular unified tagging ontology\nYear: 2011\n\nAbstract: Tagging has become a popular indexing method within the last years and can be considered one of the cornerstones of the Social Web. Several ontologies have been developed that aim to formally describe tagging and folksonomies in order to improve their interoperability and processability. However, each of these ontologies covers different aspects of the domain; finding the right ontology for a certain purpose and aligning it correctly with other ontologies is difficult. This paper critically reviews available tagging ontologies and presents a unified vocabulary that combines the 'best of' these ontologies in one consistent schema. A central goal was to ensure high concept reuse by simultaneously avoiding redundancies. A modular design was chosen to reduce complexity and prevent inconsistencies. It groups the different elements of tagging and separates advanced concepts from the core ontology. Key design decisions are justified and modeling alternatives are discussed, not only to explain the unified ontology but also to contribute to a better understanding of the conceptual space of tagging and folksonomies.","Title: Envisioning The Transformative Role Of It In Lectures\nYear: 2012\n\nAbstract: One of the most widely used methods for teaching is the lecture. During the last few decades lecturers and students have taken advantage of the progressive introduction of new technology for supporting these lectures. As this trend is very likely to continue, in this paper we will try to anticipate some possible technology enriched future lecture scenarios. We also present ALFs, a system which aims to improve the communication between participants in a lecture making use of augmented reality techniques.","Title: Advanced Transactional Models for a New Generation of Educational Modelling Language Engines\nYear: 2009\n\nAbstract: E-Learning Systems have evolved moving from self-contained simple static contents, to the design and execution of learning scenarios described by Educational Modelling Languages (EML) and the integration of web services. But also carrying with implications such as dealing with long-lived learning activities and finishing activities without accomplishing their learning objectives. Advanced Transactional Models (ATM) relax some of the basic ACID transaction properties so applications may handle in a reliable way, several types of long-lived activities and compensation activities. An EML execution engine must implement different ATMs in order to provide different levels of transaction support to deal with the diverse types of learning activities.","Title: Instinctive Game Enviroment: Exploring the Application of Natural Interfaces for Supporting Game-Based Learning\nYear: 2012\n\nAbstract: The application of computer games for learning is a field of growing interest in the education community. Games have proved to be a useful resource to teach concepts, expand perceptions, or develop skills. Typically, young children make use of recognition pattern games. This kind of games helps children to improve their knowledge and recognition skills. However, these games require someone to control the process of the game and provide feedback to the child. This paper presents a game environment based on applying the principles of natural interfaces to the development of education computer games. After realizing the proof-of-concept, we could observe that this environment allows children to interact with the games in an instinctive way seamlessly.","Title: CoDICE: balancing software engineering and creativity in the co-design of digital encounters with cultural heritage\nYear: 2014\n\nAbstract: Software engineering analysis and design methods are mainly guided by objective principles and criteria, whilst design thinking is usually fueled by subjective and people-based criteria like emotions, aesthetics or cultural and personal resonance. Complex interactive systems require a mixed approach where the benefits of both disciplines are respected: engineering and creativity, rationality and emotions, quality-centered and people-centered. This is the main purpose of a software tool, named CoDICE (COdesigning DIgital Cultural Encounters), that is being developed within the meSch EU project that is aimed at co-designing smart objects for enhanced encounters with cultural heritage. CoDICE adds persistence and traceability to the co-design activities and makes it possible to extend ideas discussion beyond collocated meetings. It also provides mechanisms to revisit design products and generate informed design rationale.","Title: I feel lucky: an automated personal assistant for smartphones\nYear: 2012\n\nAbstract: Third generation devices, such as smartphones, have the possibility of knowing the position of the user. By combining time, position and data in the Cloud it is possible to make smart deductions as to what information the user needs. These deductions can be performed by an automated assistant that have access to the user's e-mail and SMS messages, calendar, phone book, notes, etc., as well as to the position of the user. The assistant can present the information in an \"I feel lucky\" display on the user's smartphone. These concepts have been evaluated in a case study with a group of students, simulating the output of such an interface.","Title: A Meta-modeling based Approach for the Multi-Disciplinary Design of Web Educational Systems\nYear: 2009\n\nAbstract: Multi-disciplinary teams might provide a multi-faceted perspective of web educational systems that integrates experience from different fields. Each expert has a view of the system and she uses domain specific languages in order to express solutions to the problems she is concerned with. In this way, the final system can be seen as a combination of a number of complementary views, each of which focuses on problems of a different nature. However, such views are expressed with different specification tools so that they have to be integrated to produce a common design that is complete and consistent. Creating a common language encompassing multi-disciplinary design views is a challenging endeavor but it might impose a cognitive overload to each member of the group who is exposed to unfamiliar concepts of other disciplines in her design view. Alternatively, this paper describes an approach called MODUWEB that consists of letting each designer use the tool she is proficient in for her design tasks and then complementary design perspectives are integrated using meta-modeling techniques. MODUWEB also includes a number of constraints and semantic rules that guarantee the completeness and consistency of the resulting model.","Title: Improving communication for mobile devices in disaster response\nYear: 2007\n\nAbstract: During disaster response, networks can become overloaded and are susceptible to complete failure in the disaster area. This disables mobile communication, hindering response efforts from mobile users. Mobile users make use of various heterogeneous devices and require infrastructure to facilitate the communication of distributed information. Communication flow among mobile users is disorganized as it is either too strong and hierarchical or too flexible and dynamic. We have designed ubiquitous mobile infrastructures to match the response environment's communication flows and telecommunications, and produced a ubiquitous mobile communication system (ubimobcom). The design standardizes the information exchanges between mobile users. In this paper, we show that ubimobcom makes cooperation and coordination among mobile users possible at the disaster. Using ubimobcom, mobile users can be coordinated and can cooperate in outdoor areas, besides; they can continue connected with their disaster operation center. We describe the ubimobcom system to illustrate the use of communication by mobile users to disasters that may range from minor to catastrophic.","Title: Don't touch me: multi-user annotations on a map in large display environments\nYear: 2010\n\nAbstract: Touchless interaction techniques do not require physical contact while interacting with a system so to allow natural interaction with digital information, made tangible in the physical world through pervasive screen displays. In this project we explore the use of Nintendo Wii Remote controller as a touchless interface for interacting with map based applications in large displays environments. A prototype (Don't Touch Me) was developed that allows users to collaborative place multimodal annotations on a map: pictorials, auditives and haptics.","Title: Integrating Ontologies into the Collaborative Authoring of Learning Objects\nYear: 2005\n\nAbstract: Authoring learning material is a multi-disciplinary undertaking where different people can play their role. Any support that can be provided for the collaboration of instructional designers, pedagogues, media designers, and students, among others, is welcome. In particular, metadata annotation of learning objects is an important task within the whole authoring process. This work presents the first resulting products and approaches from the MD2 project, consisting of a service-oriented framework and a tool to support the integrated, ontology-based collaborative annotation of learning objects.","Title: EML Learning Flow Expressiveness Evaluation\nYear: 2009\n\nAbstract: Educational Modelling Languages such as IMS LD, LAMS and LPCEL can be used to describe a learning process, but they depict different degrees of expressiveness to represent learning flows. This paper presents an evaluation of the expressiveness of these languages based over the analysis of different workflow control patterns including basic control flow, advanced branching and synchronization, and iteration; outlining the learning process design issues.","Title: Integrating Algorithm Visualization Video into a First-Year Algorithm and Data Structure Course.\nYear: 2012\n\nAbstract: In this paper we describe the results that we have obtained while integrating algorithm visualization (AV) movies (strongly tightened with the other teaching material), within a first-year undergraduate course on algorithms and data structures. Our experimental results seem to support the hypothesis that making these movies available significantly improved students' performances. Moreover, the movies were highly appreciated by the students (both from a comprehensibility point of view and from a usefulness point of view), even though with a low attitude towards the emerging video pod-cast technology. Finally, our results indicate the necessity of integrating the AV movies with audio comment, which seems to be one of the most interesting research question left open by our study.","Title: Fuzzy Linguistic Summaries in Rule-Based Adaptive Hypermedia Systems\nYear: 2002\n\nAbstract: Rule-based adaptive hypermedia systems personalize the structure of the hypermedia space using an inference mechanism that operates on a specific knowledge representation about its users. Approximate quantifiers are very frequently used in human language expressions that entail the summarization of a large number of facts. We describe how quantified expressions can be used in adaptation rules to specify common adaptation behaviors, enhancing rule's expressive power for the human expert. Those quantified expressions can be implemented through fuzzy quantification mechanisms operating on fuzzy linguistic labels and relations, and can be integrated as extensions in general-purpose rule-based adaptive hypermedia systems.","Title: Applying software engineering methods for hypermedia systems\nYear: 2001\n\nAbstract: Despite the existence of software engineering methods for hypermedia development, this process is not as systematic as it could be expected and, in fact, the \"hypermedia software crisis\" still remains. This situation can be attributed to the scarce dissemination of methods for hypermedia. In this context, we present our experience teaching a software engineering method for hypermedia, called Ariadne, which is used to develop hypermedia applications following a user-centered approach.","Title: A Virtual Environment for Learning Aiport Emergency Management Protocols\nYear: 2009\n\nAbstract: This paper presents a virtual environment designed to enhance the learning of airport emergency management protocols. The learning is performed in an informal manner, with each learner playing a different role in a particular emergency simulation. Learners interact within the virtual environment, managing the available information and following the steps prescribed for each type of emergency in the Airport Emergency Plan of the Spanish Civil Defence Organization. The simulation can be run in different modes of difficulty, and can be used as a learning tool as well as an evaluation tool to measure the accuracy of the learner's actuation within the protocol. It can also support stand-alone training having some of the emergency roles played out by the computer. The virtual environment has been built using DimensioneX, an open source multi-player online game engine.","Title: Comparison of knowledge during the assembly process of learning objects\nYear: 2010\n\nAbstract: This paper describes the conceptual framework OntoGlue for the assembly of learning objects (LOs). To permit a coherent assembling process from the point of view of requirements and competencies, OntoGlue enhances the definition of LOs by including associated knowledge (i.e. requirements and competencies) in their conceptual data schema. This associated knowledge is defined in terms of classes of educational ontologies (used as taxonomies), possibly related by mappings. There are several advantages associated with the OntoGlue approach. Firstly, it provides an enhanced description of the LOs, which permits their search and reuse by considering requirements and competencies. Secondly, during the assembly process of two LOs, OntoGlue checks that the competencies of the first LO cover the requirements of the second LO, guaranteeing a coherent assembling process from the requirements and competencies' point of view. Thirdly, OntoGlue automatically calculates the meta-data of the resulting assembled LO. Finally, the definition of the associated knowledge in terms of classes of ontologies, possibly related by mappings, permits an advanced comparison of requirements and competencies during assembly and search processes.","Title: An Architectural Framework for Composition and Execution of Complex Learning Processes\nYear: 2005\n\nAbstract: A complex learning process (CLP) is understood as the result of the dynamic and unanticipated integration of diverse pedagogical approaches in a learning process, based on the collaboration between instructors and learners. Educational modeling languages are used to specify and design learning processes that can be adaptable to the demands of a particular pedagogical context. Based upon IMS service-oriented architectural principles, a framework for learning process composition and execution is presented. The objective of that framework is to enable the dynamic and unanticipated composition of distributed learning services. This is guided by a case study of how this framework can be implemented in a complex learning scenario.","Title: The role of evaluation in an effective development of didactic materials: The MD2 approach\nYear: 2007\n\nAbstract: Evaluation is one of the most important activities in the didactic materials development since it allows developers to check if the properties of obtained material satisfy all the requirements established at begin of its development and if that material can be an effective support to achieve the educational goals of any instructional situation. Its results are crucial data for the material redesign in such cases when those requirements or educational goals are not satisfied. Here we describe our vision of evaluation in the MD2 development approach that proposes to assess the didactic materials based on their pedagogical utility and usability.","Title: A Grid-based Architectural Framework for Composition and Execution of Complex Learning Processes\nYear: 2008\n\nAbstract: Through the past two decades, education in computer and information science and technology (CISE) has moved toward a model that pervasively incorporates programming projects and other engaging student activity. Realistic activities and materials are ...","Title: LEARNING LINKS: Reusable Assets with Support for Vagueness and Ontology-Based Typing\nYear: 2002\n\nAbstract: Existing approaches to ontological support in courseware are focused on the annotation of hypermedia nodes or contents, while links are described only by classifying them into a set of predefined types. In this work, we describe the concept of Learning-Link as an independent and reusable learning resource that can be annotated with terms defined in a link ontology. The computational semantics of that ontology, combined with fuzziness to specify gradedrelations, enables the implementation of extended adaptive behaviors that entail inferences and approximate reasoning.","Title: Participative Knowledge Production Of Learning Objects For E-Books\nYear: 2002\n\nAbstract: In a distributed learning environment, the development of learning objects is a participative task. We consider learning objects as knowledge pieces, which are subject to the management processes of acquisition, delivery, creation and production. A multiple-tier architecture for participative knowledge production tasks is introduced, where knowledge-producing agents are arranged into knowledge domains or marts, and a distributed interaction protocol is used to consolidate knowledge that is produced in a mart. Knowledge consolidated in a given mart can be in turn negotiated in higher-level foreign marts. The proposed architecture and protocol are applied to coordinate the authoring of open e-book packages as learning objects by a distributed group of authors.","Title: Modelling Static and Dynamic Aspects of Hypermedia Systems\nYear: 1997\n\nAbstract: The static and dynamic properties of the Labyrinth model, used for the definition and management of hypermedia applications, are presented in this paper. The most relevant characteristics of Labyrinth are the following: the structure of applications can be modelled by means of composite objects; the reactive nature and temporal dimension of multimedia contents are considered; and security policies to preserve information confidentiality and integrity can be defined","Title: Digitally augmented narratives for physical artifacts\nYear: 2014\n\nAbstract: In this working paper we present the design and setup of a workshop environment that empowers users with tools to create and share digital narratives associated with physical artifacts. The approach focuses on two main design choices: (1) physical embodiment, by having people directly interact with the physical objects we want to augment and, (2) situated social interactions, by offering the possibility to share personal ideas and comment on others, to collaboratively produce stories about augmented objects. We also report about the main evaluation results we got in a workshop in which we studied users needs with respect to tangible interactive experiences in exhibitions of museums.","Title: Prototyping device ecologies: physical to digital and viceversa\nYear: 2014\n\nAbstract: This Studio will involve participants creating interactions with physical and digital elements. They will have the opportunity to use a toolkit we developed that combines physical and digital widgets into a unique environment to allow the rapid setup of device ecologies. Therefore, participants will be able to explore how the toolkit support to physical/digital interaction gives people with low, when no, technical skills the possibility to rapidly prototype interactions among heterogeneous devices, thus blurring the boundaries between the physical and the digital world. The Studio is structured in two parts: in the first one, participants will get familiar with the toolkit hardware and software functionalities. In the second part they will experiment directly the toolkit capabilities by developing interactions among digitally-augmented objects in a cultural heritage context. We expect, in this Studio, people to learn what are the possibilities and challenges in the development of device ecologies.","Title: Evaluating the Runtime Adaptation of EML-Described Learning Processes\nYear: 2008\n\nAbstract: This work aims to provide the instructors of learning process specified by means of an educational language (EML) with a mechanism to modify the process definition during runtime. The paper presents the results of some experiments carried out as part of the evaluation of the envisaged solution. The core ofthe proposed solution is a model which allows the instructor to describe variations of the original learning process design, as well as to evaluate and monitor the process progress. The model is complemented with a method which organizes the performance of the instructor actions supported by the model, and a mechanism to allow its application on running instances of the process. To state the suitability of the proposed method and the expressivity of the adaptation model, the solution has been applied on three different scenarios. Three real learning processes supported on Moodle platforms have been replicated on Unit of Learning (UoL) versions described by means of IMS Learning Design(IMS LD). The adaptations and monitorizations performed by the instructors in the Moodle versions have been described using the adaptation model elements and applied to UoLs following the proposed method guidelines.","Title: Studying social technologies and communities of volunteers in emergency management\nYear: 2013\n\nAbstract: Communities of volunteers are fundamental agents in the emergency management process. In spite of the unquestionable value that social technologies could bring to such communities of volunteers it is not clear whether they are exploiting all their potential and why. This work presents a qualitative study with volunteers from different emergency communities with the purpose of establishing design challenges to better leverage social technologies that can augment the capabilities of such communities. The results of the study suggest the need to address specific design challenges related to reliability, integrity, and efficient analysis of information. In addition, the integration of multiple interaction mechanisms and shared calendars as well as the design of effective and adaptive messages for crisis communications are also considered important aspects by emergency volunteers.","Title: A transformation-driven approach to the verification of security policies in web designs\nYear: 2007\n\nAbstract: In this paper, we present a verification framework for security policies of Web designs. The framework is based on the transformation of the models that conform the system design into a formalism where further analysis can be performed. The transformation is specified as a triple graph transformation system, which in addition creates mappings between the elements in the source and target models. This allows the back-annotation of the analysis results to the original model by means of triple graphical patterns. The verification mechanisms are provided by the designer of the Web design language, together with the language specification. However, the complexities of the formalisms are hidden to the developer who uses the language. As case study, we apply these ideas to Labyrinth, a domain specific language oriented to the design of Web applications. The analysis is done by a transformation into the Petri nets formalism, and then performing model checking on the coverability graph. The framework is supported by the meta-modelling tool AToM3.","Title: Visual tag authoring: picture extraction via localized, collaborative tagging\nYear: 2008\n\nAbstract: In this work we present a system to encode location based information extracted from a media collection (the Flickr tagging system) into a single 2D physical label. This information is clustered by using locations metadata (geotags) and key-words (tags) associated to pictures. Our system helps two types of users: the user authoring the physical label and the final user who retrieves up-to-date information scanning the label with his/her camera phone. Preliminary results for a given seed word (the tag Napoli) on 3000 photographs are presented, together with some ad-hoc weighting factors that help in finding significant pictures (representing places) that can be associated to a specific area.","Title: A visual tool for using design patterns as pattern languages\nYear: 2010\n\nAbstract: Design patterns document successful solutions to recurrent problems in a specific software development domain. However, finding the patterns you need can be difficult, often requiring the designer to comprehend a long narrative description to understand the benefits, implications and trade-offs of each pattern and of its relationships with others. In this paper we propose a visual notation supported by a software tool that may help to identify patterns that could satisfy a designer's goals, as well as conveying the positive and negative relations among patterns, including dependencies and collisions among patterns selected for a specific problem. This work extends the concept of Softgoal Interdependency Graphs (SIG) enhancing them with a number of visual clues and interaction capabilities to help designers realize the contributions and trade-offs of their design ideas and the complexity of the solution space they are building up.","Title: Evaluation of an Agent-Mediated Collaborative Production Protocol in an Instructional Design Scenario\nYear: 2003\n\nAbstract: Distributed knowledge creation or production is a collaborative task that needs to be coordinated. A multiagent architecture\n for collaborative knowledge production tasks is introduced, where knowledge-producing agents are arranged into knowledge domains\n or marts, and a distributed interaction protocol is used to consolidate knowledge that is produced in a mart. Knowledge consolidated\n in a given mart can be in turn negotiated in higher-level foreign marts. As an evaluation scenario, the proposed architecture\n and protocol are applied to facilitate coordination during the creation of learning objects by a distributed group of instructional\n designers.","Title: Designing Le@Rning Objects With The Elo-Tool\nYear: 2003\n\nAbstract: Technological innovations can be important factors for change. The Internet is one such and it has modified the way people live and interact. In education, the effect of this change is. visible in the way educational materials are designed, developed and distributed, and in the roles played by the teacher/designer, the student and the content provider. Learning Objects technology? and supporting tools now permits the generation of on-line educational materials. This paper presents a framework for the generation, integration and reuse of Learning Objects, intended to (a) resolve the limitations of existing tools (b) provide interoperability between Learning Objects, and (c) provide mechanisms to compose new learning objects from old.","Title: Modelling Computer Game Based Educational Experience for Teaching Children about Emergencies\nYear: 2010\n\nAbstract: The aim of this work is to support educators in the design process of computer game based learning experiences for teaching children about the risks of emergency. As an educational experience can be tailored to different student needs, the risk characteristics of emergency at hand, and the educational purpose of the experience, the proposed model includes the necessary elements to provide all this information. In this way the teacher can specify the requirements of the educational experience, and based on this information to propose possible configurations of the elements of the game.","Title: MD2 method: the didactic materials creation from a model based perspective\nYear: 2006\n\nAbstract: The creation of didactic materials is a complex task that needs an effective support for all practitioners involved in such process. This is the goal of the MD2 method presented in this paper. We propose the MD2 model to describe didactic materials requirements like its contents, pedagogical, technical and quality features. The rationale is to use some of those descriptors to provide mapping from high level technical descriptions of learning technology standards to simpler and closer descriptions to practitioners about material requirements. Those model mappings are used as foundation of MD2 creation method, and we show how they can guide the selection and composition phases of creation. By other side, another set of MD2 descriptors are used in the evaluation phase to control the usability and quality of the obtained material. A log of the whole process including the values of all model elements and the material's design rationales will be stored as extended semantic annotation. Thus, important properties of the created material like its interoperability, accessibility and reusability will be ensured.","Title: Foreseeing the Transformative Role of IT in Lectures\nYear: 2011\n\nAbstract: One of the most widely used methods for teaching is the lecture. During the last few decades lecturers and students have taken advantage of the progressive introduction of new technology for supporting these lectures. As this trend is very likely to continue, in this paper we will try to foresee some possible technology enriched future lecture scenarios.","Title: Erratum Corrections to 'Modeling the Dynamic Behavior of Hypermedia Applications'\nYear: 2001\n\nAbstract: First Page of the Article","Title: Supporting Efficient Multinational Disaster Response through a Web-Based System\nYear: 2002\n\nAbstract: The current process to deal with disaster mitigation has a number of drawbacks that can be solved using web technology. The basic problem is that there is a unidirectional and asynchronous flow of information among the different agents involved in a disaster mitigation procedure. This situation often results in a lack of coordination in the resources provision and in a useless assistance. In this paper we introduce ARCE, a web based system envisaged to cope with the lack of synchronism among assistance requests and responses in a multinational environment as the Latin-American Association of Governmental Organisms of Civil Defence and Protection is. ARCE makes uses of role-based access policies (RBAC) and information flow mechanisms to offer an efficient and reliable communication channel.","Title: A Framework for the Multi-disciplinary Design of Web-Based Educational Systems\nYear: 2009\n\nAbstract: The communication and the collaboration in a multi-disciplinary team can be diminished due to the different specification tools and languages used by the diverse members of the team. The MODUWEBapproach tackles this problem allowing the integration of different design perspectives through Model-DrivenDevelopment (MDD) techniques. Such integration is completely transparent to the users of the modeling languages, that is, the designers of the web-based educational systems, and in this way their productivity is not affected. This paper describes a prototype of a system which implements the MODUWEB approach to combine two domain specific languages dealing with different perspectives of the design of a Web-based educational system: IMS Learning Design for educational design and Labyrinth for web design.","Title: Extending Relational Data Access Programming Libraries for Fuzziness: The fJDBC Framework\nYear: 2002\n\nAbstract: Fuzzy relational databases have been extensively studied in recent years, resulting in several models and representation techniques, some of which have been implemented as software layers on top of diverse existing database systems. Fuzzy extensions to query languages and end-user query interfaces have also been developed, but the design of programming interfaces has not been properly addressed yet. In this paper, we describe a software framework called fJDBC that extends the Java Database Connectivity API by enabling fuzzy queries on existing relational databases, using externally-stored metadata. Since the main design objective of this extension is usability for existing database programmers, only a restricted subset of extensions (supported also by an extended object modelling notation) has been included. The overall design of the framework and some empirical results are also described.","Title: Bridging the communication gap: a user task vocabulary for multidisciplinary web development team\nYear: 2012\n\nAbstract: The design of Web-based systems is specially characterized by the multidisciplinary nature of Web Development Teams (WDTs). Due to this multidisciplinary, WDT members use different terminology that can lead to misunderstanding along the development process and, consequently, affect the resulting design. This problem has been identified during the physical design of websites, characterized by the sharing of ideas and the need of reaching a common understanding of the problem. With the purpose of avoiding misunderstanding among WDT members during this phase, it is proposed a controlled vocabulary of web user task. The definition of the vocabulary is based on the analysis of interaction design patterns. The paper describes the definition process followed for the construction of the user task vocabulary as well as the vocabulary itself. The final version of the controlled vocabulary compiles a total of thirty-four web user tasks and forty-one semantic relationships represented as synonyms. The vocabulary has been assessed through a heuristic evaluation, proving its correctness and completeness.","Title: The collaborative development of didactic materials.\nYear: 2005\n\nAbstract: In this paper we present an analysis of the development process of technology-supported didactic material. Such analysis considers didactic materials as the conjunction of contents and in- structional design used to guide learning and teaching processes. And we examine why several features such as reusability, semantic interoperability and collaboration support must be ensured from the earlier stages of the material creation process. For those reasons di- dactic material development is not a trivial task and demands of a development methodology support and a high-quality authoring en- vironment. We describe how the MD2 research project provides an integrated solution for creation of didactic materials that take into account those rationales. The MD2 solution is based on two ap- proaches: first, the definition of a method for the collaborative crea- tion of didactic materials and second, the elaboration of a quality evaluation framework for a priori testing of educational products. We also present CASLO a collaborative authoring tool used to facilitate these endeavors.","Title: A Design Toolkit For Hypermedia Applications Based On Ariadne Development Method\nYear: 2004\n\nAbstract: The development process of hypermedia applications implies very specific problems mainly related, first, to the use of navigational structures, interactive behaviours and multimedia compositions, and second, to the fact that are used by users with different levels of knowledge and skills, and also different security levels. This paper presents a design environment, AriadneTool, that allows a designer to model a hypermedia application, to validate such a design and to generate dynamically XML + SMIL implementation templates. This environment is based upon the Ariadne method which offers a set of integrated activities to model hypermedia applications in a systematic and iterative way. A practical example is shown to illustrate the use of the tool in the development of a hypermedia application.","Title: Understanding citizen participation in crisis and disasters: the point of view of governmental agencies\nYear: 2014\n\nAbstract: Ubiquitous computing combined with web 2.0 technologies might contribute to develop a culture of participation in emergency management (EM) by aligning the efforts and capabilities of official agencies and citizens. For citizen participation to be possible organizations in charge of EM need to realize that involving citizens does not interfere with their protocols and citizens need to be empowered to move beyond the role of passive informants. In this paper we describe how organizations perceive this participation as a step further to understand how to reach a more participative model and the benefits that technology and sociotechnical systems might bring to such model.","Title: Standardizing the narrative of use cases: A controlled vocabulary of web user tasks.\nYear: 2013\n\nAbstract: Context: For user interfaces design, the use of appropriate terminology in writing use case narratives may determine the effectiveness of the design process, facilitating communication within multidisciplinary web development teams and leading to agreed designs.Objective: This paper proposes a user task vocabulary for web user interface design. This vocabulary compiles terms related to the use of web applications, regardless of the application domain, as a way of standardizing the terminology used in the elaboration of use case narrative. The use of the vocabulary would help to reduce misunderstandings within multidisciplinary web development teams.Method: The construction of the vocabulary is based on the combination of both committee and empirical approaches. Committee approaches rely on experts in designing web applications, while empirical ones are focused on analyzing content objects, such as interaction design patterns and use case narratives.Results: The final version of the monolingual controlled vocabulary of web user tasks compiles a total of 40 tasks; each of them has a key term and a definition of the interaction carried out by users. Additionally, 41 semantic relationships were collected and represented as synonyms. The vocabulary has been assessed through an expert evaluation, proving its correctness and completeness, and an usability evaluation checking the efficacy of the vocabulary.Conclusion: The language employed in use case narratives can determine the value of use cases for designing user interfaces. The usage of a controlled vocabulary may allow designers to elaborate unambiguous use case narratives as a way of creating consistent task models for designing web user interfaces. (c) 2013 Elsevier B.V. All rights reserved.","Title: Modelling Security Policies in Hypermedia and Web-Based Applications\nYear: 2001\n\nAbstract: As hyperdocuments grow and offer more and more contents and services, some of them become more sensitive and should only be accessed by very specific users. Moreover, hypermedia applications can offer different views and manipulation abilities to different users, depending on the role they play in a particular context. Such security requirements have to be integrated into the development process in such a way that what is understood by a proper and safe manipulation of a hyperdocument has to be analysed, specified and implemented using the appropriate abstractions. In this paper we present a high-level security model applied to the modelling of security policies using components and services belonging to the hypermedia domain. The model uses negative ACLs and context-dependent user permissions for the specification of security rules. An example of its use for the design and operation of a web-based magazine is also described.","Title: The Evaluation within the Development and Deployment of IMS LD-Based Didactic Materials: The MD2 + Runtime Adaptation Approach\nYear: 2008\n\nAbstract: Evaluation is one of the most important activities in the didactic materials creation since it allows developers to check if the features of created material satisfy all the requirements established at begin of its development and if that material can be an effective support to achieve the educational goals of a particular instructional situation. Its results provide relevant information for the material redesign in such cases when those requirements or educational goals are not satisfied. In this paper we describe an approach to evaluate IMS LD-based materials during their development and deployment in an educational process.","Title: WAY: An Architecture for User Adapted Access to Z39.50 Servers Based on Intelligent Agents\nYear: 1998\n\nAbstract: The work presented in this poster is based on the combination of three well-known paradigms of Computer Science applied to\n Digital Libraries: User Adaptive Interfaces, Information Retrieval and Intelligent Agents. Its objective is to define a model\n providing intelligent information access by means of an adaptive user interface. The model, called WAY (see figure 1), is\n supported by a web-based architecture and counts on the help of intelligent agents in charge of studying the user characteristics\n in terms of previous behaviours, in order to provide an adapted interface and to guide the user’s searching process through\n the servers available in the net. This model is currently being implemented in java using RMI (Remote Method Invocation) technology.\n \n Concerning user adaptive interfaces, what our model proposes is to offer a different initial interface for each type of user.\n These initial interfaces will be defined according to the users classification, taking into account where the user is accessing\n the system from. Once the user begins to interact with a specific interface, it will go on changing depending on the actions\n performed by the user in two ways: the preferences shown explicitly by the user -selected options in the configuration of\n the interface- and the preferences shown implicitly -by systematic actions. The following examples illustrate these ideas:\n \n \n \n \n – \n The type of user: in a university library environment, the possible types could be students, teachers and library staff, all\n of them with quite different goals and needs.\n \n \n \n – \n The user mother tongue: if the user is connecting from Germany, he/she is likely to prefer a German interface.\n \n \n – \n The user preferences: there are people who still prefer textual environments although their computers allow a good performance\n of visual ones.\n \n \n \n – \n The user repeated actions: in a university, students usually are more interested in books than in journals, unlike teachers,\n whose main research tools are papers.","Title: LPCEL Editor: A Web-Based Visual Authoring Tool for Learning Design\nYear: 2012\n\nAbstract: Educational Modeling Languages (EMLs) provide the framework to represent learning processes in a formal fashion. The IMS-LD is a widely used EML and there have been created several tools to facilitate the authoring process of a course for that specification. However, since most of these tools are meant to be IMS-LD complaint they are also restricted by its level of expressiveness. To solve this issue, the LPCEL Editor is presented to facilitate the authoring of a course by means of a visual tool while maintaining a broad level of expressiveness.","Title: Designing Educational Games by Combining Other Game Designs\nYear: 2012\n\nAbstract: The complexity and sophistication of computer games is growing every day, not only in terms of graphical resources and advanced interaction mechanisms but also with regards to their narratives and their rules. In this paper we propose to tackle the complexity related to the rules and narratives of a game design by describing it through combinations of more simple game designs. This approach not only facilitates the description of game designs that are easy to manage and understand but also enables the reuse of game design components, and also allows the designer to respond to established trends in computer games such as the use of \"missions\" and \"mini-games\". The proposed approach has been applied to the design and implementation of an educational game (EG) called \"Safety Village\" of the minigame genre, which aims to help raise children's awareness of emergencies and domestic risks.","Title: Designing usable educational material for English courses supported by mobile devices\nYear: 2010\n\nAbstract: Mobile Learning (M-Learning) may offer many advantages when designing educational processes as it can help to overcome restrictions of time and place. However, it is necessary to consider the special features of the type of devices used to follow these type of courses in order to guarantee the usability of the learning objects produced for this eLearning modality. In this document we describe the process of designing a set of courses which aim to support learners when developing English grammar, reading and listening skills, explaining the guidelines we have followed to ensure the usability of the final product.","Title: Web Design Patterns: Investigating User Goals and Browsing Strategies\nYear: 2009\n\nAbstract: Design patterns document in a systematic way design solutions to recurrent problems and they are expressed using non-technical terms, so that a wider audience can understand them. Thus they could be useful tools to improve communication in interdisciplinary teams and to integrate end-users in participatory design processes. However, the difficulties of using patterns go beyond the lexicon used in the patterns description. The individuals who might use the patterns may be following different strategies when browsing a collection of patterns, strategies that are determined by their goal at a specific point during the development process. Moreover, the strategy they follow can have some influence in the quality of the proposed solution. In this paper we describe an empirical study that has been performed to answer some of these questions. In the study we gathered information on browsing strategies and user goals when using a patterns catalogue to design a web system. We also analyzed the relation among the goal and the strategy as well as their impact in the quality of the use of the patterns. This investigation is part of a larger project intended to design patterns catalogues that take into account the goals and expectations of their end-users, who are not necessarily experts either on web design or on design patterns.","Title: Modelling hypermedia and web applications: the Ariadne development method\nYear: 2005\n\nAbstract: The development process of hypermedia and web systems poses very specific problems that do not appear in other software applications, such as the need for mechanisms to model sophisticated navigational structures, interactive behaviors, interfaces with external applications, security constraints and multimedia compositions. Even though experience, modelling skills and abstractions can be borrowed from existing software design methods, such as object-oriented modelling, hypermedia developers need specific mechanisms to analyze and design using entities that belong to the hypermedia domain (such as nodes, links, anchors and space and time-based relationships). Moreover, hypermedia methods should provide mechanisms to deal with all the aforementioned features in a progressive and integrated way. In this paper, we present the Ariadne Development Method (ADM), a software engineering method that proposes a systematic, flexible, integrative and platform-independent process to specify and evaluate hypermedia and web applications. ADM has been shown particularly useful in complex systems involving a huge number of users with different abilities to access information, with a complex structure where a huge number of nodes have to be organized in a clear way to produce specifications that are discussed by people with an heterogeneous background. This is the case of ARCE, a Latin American project where 21 countries are cooperating to produce a web platform to improve assistance in disaster mitigation situations.","Title: The Automatic Generation of Semantic Annotations for Didactic Materials and the Use of Models in the Material Development to Improve its Reusability\nYear: 2008\n\nAbstract: Through the past two decades, education in computer and information science and technology (CISE) has moved toward a model that pervasively incorporates programming projects and other engaging student activity. Realistic activities and materials are ...","Title: Instructional Software Analysis: Lessons From Software Development Process Improvement\nYear: 2007\n\nAbstract: Instructional software can be defined as any computer program used for instruction. As a means to optimise the development process of instructional software, different authors have defined a range of methods based on Software Engineering. However, the use of a method does not guarantee the validity and quality of the product developed; hence, a series of Software Process Improvement (SPI) approaches aimed to improve and guarantee the development process that have arisen.The purpose of this paper is to review the aforementioned approaches and to apply them to the analysis phase of the instructional software development process. The analysis phase aims to define the conditions and needs of the project in order to solve uncertainties in early stages of the process.","Title: Formalization of web design patterns using ontologies\nYear: 2003\n\nAbstract: Design patterns have been enthusiastically embraced in the software engineering community as well as in the web community since they capture knowledge about how and when to apply a specific solution to a recurring problem in software systems. However, web design involves both cognitive and aesthetic aspects, for that there are several design patterns that describe the same problem but from different points of view and with different vocabulary, so it is more difficult to understand and to reuse that knowledge. To achieve a common vocabulary and improve reusability we propose to formalize web design patterns by means of ontologies. At the same time the ontology would allow us to express web design patterns in a formal way, that can be understood by a computer. So a design pattern knowledge base can be integrated in a software tool for web application modeling in order to suggest web design patterns that better suit some design requirements. Moreover, changes and alterations needed for applying design patterns to the design can be proposed. This paper describe the core ontology using DAML+OIL and show how web design patterns can be described by our ontology.","Title: Instructional Domain Analysis: A Methodological Approach to Service-Oriented Learning\nYear: 2008\n\nAbstract: The development of a learning system based on integrating a number of learning services needs both a technological platform to support the system as well as a methodology that manages the development process. Such technological platform is provided by the service oriented learning architecture (SOLA) that defines an architecture style guiding several aspects of deploying units of learning that are packaged as services. The purpose of this paper is to review the SOLA concept and present a specific methodology, based on analysing instructional domains, to complement the SOLA approach. The method here proposed addresses the identification and classification of learning services to facilitate the integration of such services.","Title: A modular approach to support the multidisciplinary design of educational game experiences\nYear: 2012\n\nAbstract: The design of a computer game based educational experience is a multidisciplinary task that requires the collaboration of experts in game design, education and in the field of instruction. In this paper we present an educational game (EG) design method which tackles this multiplicity of backgrounds allowing each of the experts to focus on the aspects of the game design related to his/her area of expertise. The method is supported by a modular conceptual model that provides a common framework for describing an EG and facilitates the reuse of design components and the description of new game variants. In order to illustrate the proposal we describe the process of design and implementation of 'Maz-E-nglish', an EG for mobile devices which aims to help children learning English grammar.","Title: From requirements to implementations: a model-driven approach for web development\nYear: 2007\n\nAbstract: Model-Driven Development (MDD) is an appropriate paradigm for web development since interoperability and flexibility are required to cope with implementation technologies and functionalities that are in permanent evolution. In this paper, we describe and illustrate the MDD process of the ADM (Ariadne Development Method) hypermedia/web engineering method. The two cornerstones of the ADM are the Labyrinth++ meta-meta-model, which formalizes the core constructs used within all the design meta-models, and the meta-meta-model specification as an ontology that provides semantics and reasoning not only for model transformations but also for consistency checking and model validation. These features have been essential in the development of a CASE tool, called AriadneTool that supports the different abstract levels of modeling, model transformations as well as the generation of light prototypes in different web implementation technologies.","Title: Interactive Accessible Notifications for Emergency Notification Systems\nYear: 2009\n\nAbstract: Notifications are critical when an emergency scenario is going to happen (e.g. a hurricane approaching); so the ability to transmit notifications to different kind of users is a crucial feature for Emergency Management Systems. In this work an ontology was developed by investigating different sources: accessibility guidelines, emergency response systems, communication devices and technologies, taking into account the different abilities of people to react to different alarms (e.g. mobile phone vibration as an alarm for deaf blind people). The knowledge codified in the proposed ontology could be used to enhance and promote the use of non-conventional interfaces for notifying emergency messages thus providing accessibility under different conditions and for different kind of users.","Title: Visual representation of web design patterns for end-users\nYear: 2008\n\nAbstract: In this paper, we discuss the use of visual representations of web design patterns to help end-users and casual developers to identify the patterns they can apply in a specific project. The main goal is to promote design knowledge reuse by facilitating the identification of the right patterns, taking into account that these users have little or no knowledge about web design, and certainly not about design patterns, and that each pattern might include some trade-offs users should consider to make more rational decisions.","Title: Assessing the utility of an interactive electronic book for learning the Pascal programming language\nYear: 2000\n\nAbstract: Hypermedia is a broadly accepted technique to develop educational systems since its hypertext structure reflects a model of learning based on the students' semantic memory model and the use of multimedia provides interactive mechanisms that allow managing, manipulating and organizing the lessons. A hypermedia electronic book called CIPP (Curse Interactive de Programacion en Pascal) is introduced to help students learn the Pascal programming language and the empirical evaluation that was carried out to assess the book utility as an educational tool. One of the most encouraging results from this experience was that, at the end of the course, not only did most students agree with the didactic method which integrated lectures with the use of the electronic book, but also they felt motivated to continue learning Pascal by themselves.","Title: CARLOS: A Collaborative Authoring Tool for Reusable Learning Objects\nYear: 2003\n\nAbstract: The development of learning contents is a collaborativeprocess in which, users with different backgrounds, experiencesand points of view can take part. This is a two-stepprocess: first, a negotiation and evaluation of ideasamongst participants and second, composition of learningcontents as result of that negotiation. However the collaborativedevelopment support in current learning contentsauthoring tools is scarce, since they usually providea uni-personal vision of the creation process. This workpresents a multi-agent system for the collaborative authoringof Reusable Learning Objects (RLO), which key featuresare: (1) collaboration stakeholders are representedby agents; (2) agents message exchange is coordinated bymeans of a negotiation protocol; (3) agents rationality forproposal evaluation is modelled in terms of preference relationships;(4) a group of assistant agents trace all negotiationevents, so allowing the whole creation process to beaudited, whilst keeping a repository to control changes accomplishedinto the RLO corpus, thus allowing automatedconsolidation of negotiated results.","Title: Learning Web Services Composition and Learner Communities Support for the Deployment of Complex Learning Processes\nYear: 2004\n\nAbstract: Educational models are subject to a constant evolution and permanent technological developments, with new visions and learning models emerging to face them. These usually include diverse didactic strategies into the learning process. Learning Management Systems currently evolve towards distributed learning object systems with decentralized execution and integration with heterogeneous applications. The notion of a centralized repository of learning objects should change onto distributed communities of learning objects producers and consumers. In this paper, we present a learning web services framework to support the integration of newer, complex learning processes and the dynamic generation of content-based communities of interest. Nowadays, educational models are immersed in a constant knowledge evolution and permanent technological development, new challenges arise from that globalized environment, thus, a new vision and learning models should emerge in order to face them. These new models must include diverse didactic techniques strategies in the learning process. We also believe that actual Learning Management Systems (LMS) should evolve towards integrating systems of distributed learning objects with decentralized execution and integration with heterogeneous applications; the notion of a centralized repository of learning objects should change onto distributed communities of learning objects producers and consumers. In this paper, we present a learning web services framework to support the integration of newer, complex learning processes and the dynamic generation of content-based communities of interets.","Title: Collaborative hypermedia systems: A model of architecture\nYear: 1997\n\nAbstract: CO-OPERATIVE AUTHORING IN HYPERMEDIA SYSTEMS have recently gained importance to such an extent that the next generation of\n hypermedia systems should be defined with the acronym IOCH: Integrated Open and Collaborative Hypermedia. An architecture\n model supplies a set of modules and interfaces that allow systems facilities and components to be specified. This paper presents\n a model of architecture for IOCH systems that tackles problems associated with this kind of environment, such as system openness\n and distribution, information security and collaborators’ communication. This model has been developed taking into account\n three basic principles: modularity, abstraction, and IOCH support.","Title: Requirements for Hypermedia Development Methods: A Survey of Outstanding Methods\nYear: 2002\n\nAbstract: The aim of this paper is to present a framework of requirements to survey design methods for hypermedia systems. Such requirements are taken from software engineering as well as from hypermedia engineering fields. Finally, these requirements are applied to a set of outstanding design methods in order to identify both their good qualities and their lacks.","Title: A model-driven approach for the visual specification of Role-Based Access Control policies in web systems\nYear: 2008\n\nAbstract: Specifying the access policy of a web system is a relevant design concern that is often dismissed or postponed until the implementation. ADM-RBAC (Ariadne Development Method with Role-Based Access Control) is a model-driven approach for web systems that supports the specification of access control policies in an integrated way and at two abstraction levels. At the conceptual level a number of visual models specify the access policy in a way that is similar to the users’ point of view. At the detailed level, models are oriented towards providing enough details to generate prototypes in an automatic or semiautomatic way. In this paper we describe the visual models of ADM-RBAC and their empirical evaluation.","Title: Using recommendations to help novices to reuse design knowledge\nYear: 2011\n\nAbstract: The use of pattern languages is not so straightforward since itsusers have to identify the patterns they need, browsing the language and understanding both the benefits and trade-offs of each pattern as well as the relations and interactions it has with other patterns. Novice designers might benefit from tools that assist them in this learning task. In this paper we describe a recommendation tool embedded in a visual environment for pattern-based design which aims at suggesting patterns to help novice designers to produce better designs and understand the language.","Title: ELO-Tool: Taking Action in the Challenge of Assembling Learning Objects\nYear: 2008\n\nAbstract: Nowadays, a wide range of initiatives are focused on providing solutions relating to the integration and reuse of different types of learning objects. This paper deals with the assembly of learning objects, one of the most difficult components for reuse. Our proposal takes into account the requirements and competencies defined for each learning object in order to allow them to be assembled in a coherent way. As a result of this approach, we have developed ELO-Tool, a web application that implements an assembly mechanism based on a semantic comparison of requirements and competencies through the use of ontologies. Moreover, the application generates the appropriate set of meta-data to describe the new learning objects resulting from the assembly process.","Title: A Mixed Interaction Platform For Supporting Large-Scale Crisis Storytelling\nYear: 2013\n\nAbstract: Crowdsourcing is a distributed approach in which people participate and share information over the Web (e.g. Facebook or Twitter). This distributed model has proved to be helpful in accelerating the perception of what occurred, where it happened, and who needed help in recent disasters such as the Boston Marathon bombs, the Oklahoma tornado or the Central Europe floods. Nevertheless, this kind of sources might provide unreliable, partial, ambiguous and inconsistent information that do not necessarily help to understand the situation. An alternative may be the combination of crowdsourcing activities and more official flows of information to make up a coherent big picture that support the needs of decision makers. This paper introduces a software approach conceived to convey stories created from different sources -official and unofficial-as a way of depicting situations in a collaborative manner.","Title: A Collaborative Authoring of Learning Scenarios Using the LPCEL Editor\nYear: 2013\n\nAbstract: Learning scenarios are formally represented through Educational Modeling Languages (EMLs). The IMS-LD is a commonly used EML and several compliant visual editors are being created for the authoring of learning scenarios. However, these editors have a limited level of expressiveness. The LPCEL Editor facilitates the authoring process with a visual tool that includes the mechanisms for a collaborative authoring process while providing a broad level of expressiveness.","Title: A Web Service for Hypermedia Role-Based Policies\nYear: 2005\n\nAbstract: High level security is a key requirement in hyperme- dia/web applications. The systems opening to the Internet makes the research effort to move towards protecting the information transmission (i.e. SOAP messages, policy de- scriptions. . . ), but little attention is paid to what the user can do with the system. Role-based access control (RBAC) allows to formulate the organization's resource access pol- icy in a natural way, so a role-based access model for hy- permedia will make it easier to integrate the security design with the rest of the system design. In service oriented archi- tectures, an access policy service would allow to gather the management and deployment of the security policy in dis- tributed and heterogeneous environments. This paper de- scribes a role-based access control model for hypermedia called MARAH, and its implementation as a web service. An use case of the model in the design of the ARCE appli- cation is also discussed.","Title: Sharing your view: A distributed user interface approach for reviewing emergency plans\nYear: 2014\n\nAbstract: Emergency planning is an ongoing activity in which a multidisciplinary group of experts intermittently collaborate to define the most appropriate response to risks. One of the most important tasks of emergency planning is the review of plans as a way of maintaining, refining, and improving them. This review of plans is based on exchanging knowledge and experiences in order to take into account different perspectives and generate alternative solutions. An exploratory case study carried out within municipal organizations has disclosed how the application of rigid plan reviewing practices hinders team creativity and, consequently, effective decision-making. This paper presents a computer-based collaborative environment aimed at supporting unstructured team discussion during the post-hoc review of emergency plan. This collaborative environment allows emergency planning team members to share their view in a free manner by interacting with user interface components distributed across several input and output dimensions. The usage of the environment has proved how the application of new interactive technologies can create more dynamic work settings, fostering team creativity.","Title: Spreading design patterns with semantic web technologies\nYear: 2006\n\nAbstract: There are a huge number of design patterns that can be used in specific software domains, not only in object-oriented software design. Several of these collections are disseminated as structured but informal documents, at best supported with hypertext tools on the web. These passive representations compromise usability of design patterns. We proposed to enrich the textual pattern description with semantic annotations that enable a machine and a human understanding, like in the Semantic Web. In this paper, we present an annotation tool to support the development of semantic pattern repositories. Moreover, in order to show the utility of this approach two software tools with different purposes have been developed: a semantic web repository to explore patterns and a pattern wizard to apply patterns into a design toolkit.","Title: A hypermedia course in Spanish informatics engineering\nYear: 1997\n\nAbstract: Public and private companies are continuously asking to the Professional Orientation Service of the University Carlos III de Madrid for technical engineers in informatics trained in areas related to hypermedia technology. For this reason, the Department of Computer Science of UC3M decided to create a new course, called \"Hypermedia Systems: Design and Evaluation,\" with a view to covering this subject applying basic principles of software engineering and HCI. This paper describes the structure and contents of this new course oriented towards introducing students in hypermedia systems and also presents our experience as the teachers of such course.","Title: An Ontology-Based Mechanism for Assembling Learning Objects\nYear: 2005\n\nAbstract: This paper presents OntoGlue, an ontology-based mechanism for assembling learning objects. This mechanism introduces the concept of associated knowledge, which represents the set of requirements that a learning object needs in order to be used and a set of competencies that the learning object provides after its comprehension. According OntoGlue, in order to assemble two learning objects, the requirements of one learning object must be covered by the competencies of the other. In addition, to facilitate interoperability between different domains (vocabularies), the concepts that conforms the associated knowledge are selected among the classes of educational ontologies.","Title: A methodological approach for hypermedia security modeling\nYear: 2003\n\nAbstract: In hypermedia systems security is becoming a key requirement to preserve both confidentiality and integrity. Although some authorization models for hypermedia have been proposed, what is needed is to integrate security modeling into the whole development process, so that designers count on methods to specify all the features of their hypermedia systems, including navigation capabilities, interactivity, multimedia features as well as security. In this paper, we describe how security modeling is approached in a methodology for hypermedia systems, called Ariadne, that offers a number of conceptual and platform-independent tools to specify the features of any hyperdocument in an integrated and progressive way.","Title: Augmented Presentations: Supporting The Communication In Presentations By Means Of Augmented Reality\nYear: 2014\n\nAbstract: This work aims to explore the benefits and potential uses of Augmented Reality technology for supporting communication in presentations. This article presents the architecture and implementation of an Augmented Presentation Feedback System. The system allows a speaker equipped with an Augmented Reality Head-Mounted Display to display visual cues depicted over the listeners' heads. These can be used as a way to provide the speaker with continuous, private, and immediate feedback on his or her explanations. The results of a case study conducted showed that the system not only assists the speaker in adapting the content and pace of the explanation to the listener but also helps to better manage their interventions and improve the flow of the presentation.","Title: Citizen Participation and Social Technologies: Exploring the Perspective of Emergency Organizations.\nYear: 2014\n\nAbstract: Current technological advances on ubiquitous computing and web 2.0 open up new possibilities to promote an active participation of citizens in different domains including emergency management. Such a kind of participative model requires not a proactive attitude from citizens but also of the implication of emergency management organizations that have the responsibility of managing the situation. Emergency management is a highly professional domain characterized by the stress that emergency workers experience when facing unpredictable events that have a social and economic impact in society. Citizens could contribute in this process as far as they do not interfere with the protocols and activities of professional workers who will not accept any change that could compromise their efficacy. Many research works focus on how citizens utilize social technologies during emergency situations for self-organizing or for citizen journalism, however, the perspective of emergency management organization has been less explored. In this paper, we present a study that goes deeper into how organizations envision the use of technologies to increase citizen participation in their procedures. This study aims at being a step further to understand how a more active and effective citizen role could be reached and how technologies could contribute to this end.","Title: Exploring Interaction Possibilities in Educational Games: A Working Proposal\nYear: 2014\n\nAbstract: The design of the user interfaces for educational games (EGs) poses specific challenges, as this feature does not only have an impact on the game playability but can also be used to reinforce learning or to establish associations between concepts. However, implementing advanced in-game interactions can be an issue due to the wide range of technologies for defining input modalities, actions and events that game designers need to consider. In this working paper, we propose an approach to ease the development of educational games that go one step beyond classical mouse and keyboard interaction and provide interaction alternatives within the same game rationale. Our proposal is based on the integration of a game design model and an ubicomp interaction toolkit that manages heterogeneous devices.","Title: Human-Display Interaction Technology: Emerging Remote Interfaces for Pervasive Display Environments\nYear: 2010\n\nAbstract: We're living in a world where information processing isn't confined to desktop computers-it's being integrated into everyday objects and activities. Pervasive computation is human centered: it permeates our physical world, helping us achieve goals and fulfill our needs with minimum effort by exploiting natural interaction styles. Remote interaction with screen displays requires a sensor-based, multimodal, touchless approach. For example, by processing user hand gestures, this paradigm removes constraints requiring physical contact and permits natural interaction with tangible digital information. Such touchless interaction can be multimodal, exploiting the visual, auditory, and olfactory senses.","Title: Seeking Reusability of Computer Games Designs for Informal Learning\nYear: 2011\n\nAbstract: In order to enjoy the benefits that the use of computer games may provide for supporting the area of informal education, it is necessary to rely on design models, methods and tools to help reduce the high costs traditionally associated with the development of these kinds of systems. In this paper we present a model which seeks to facilitate the reuse and adaptation of designs of these types of games. The model has supported the implementation of two different games for training children on emergency situations.","Title: Personalized alert notifications and evacuation routes in indoor environments.\nYear: 2012\n\nAbstract: The preparedness phase is crucial in the emergency management process for reaching an adequate level of readiness to react to potential threats and hazards. During this phase, emergency plans are developed to establish, among other procedures, evacuation and emergency escape routes. Information and Communication Technologies (ICT) can support and improve these procedures providing appropriate, updated and accessible information to all people in the affected zone. Current emergency management and evacuation systems do not adapt information to the context and the profile of each person, so messages received in the emergency might be useless. In this paper, we propose a set of criteria that ICT-based systems could achieve in order to avoid this problem adapting emergency alerts and evacuation routes to different situations and people. Moreover, in order to prove the applicability of such criteria, we define a mechanism that can be used as a complement of traditional evacuation systems to provide personalized alerts and evacuation routes to all kinds of people during emergency situations in working places. This mechanism is composed by three main components: CAP-ONES for notifying emergency alerts, NERES for defining emergency plans and generating personalized evacuation routes, and iNeres as the interface to receive and visualize these routes on smartphones. The usability and understandability of proposed interface has been assessed through a user study performed in a fire simulation in an indoor environment. This evaluation demonstrated that users considered iNeres easy to understand, to learn and to use, and they also found very innovative the idea to use smartphones as a support for escaping instead of static signals on walls and doors.","Title: Software Support for Multitouch Interaction: The End-User Programming Perspective.\nYear: 2016\n\nAbstract: The hardware development of the past years favored the widespread diffusion of multitouch devices (such as smartphones, tablets, and interactive tabletops) to such an extent that a wide variety of users are now exploiting them to perform different activities on a daily basis. In the heterogeneous and manifold context of modern computation, it is impossible to predict, at design time, all the possi...","Title: Designing educational games through a conceptual model based on rules and scenarios\nYear: 2015\n\nAbstract: The design of a successful educational game (EG) is a challenging task that requires a lot of knowledge and a variety of skills. EG designers not only have to deal with the inherent technical complexity of game design, but also have to be able to interweave learning activities in a way that is enjoyable and educationally effective at the same time. In order to make available the benefits of game based learning to a wider audience, it is necessary to provide means to alleviate the cost of envisioning new EG by providing tools that might contribute to make the design process easier and quicker. As a first step towards this goal, in this paper we introduce a conceptual model that organizes in a modular way and in different design perspectives the game features. In order to help EG designers, the features that are most often regarded in the literature as significant in producing engaging, fun and educational game experiences, have been included in the model through a set of design entities. Furthermore, the organization of the elements of the model facilitates reusing pieces of the EG designs to quickly produce variants of the same game which can be used to match different learning purposes. The opinions gathered from the educators and game designers that participated of an EG design workshop confirmed that the model can help multidisciplinary EG design teams. Moreover, the model successfully contributed to the process of designing a collection of EGs aimed at raising children ́s awareness of emergencies and domestic risks, whose educational and ludic value was assessed in an experience conducted with students and educators at a primary school in Madrid.","Title: An Augmented Lecture Feedback System to Support Learner and Teacher Communication.\nYear: 2013\n\nAbstract: In this paper, it is advocated that the feedback loop between learners and teachers could be improved by making use of augmented reality (AR) techniques. The bidirectional communication between teacher and learners is sometimes hampered by students' fear of showing themselves up in front of their classmates. In order to overcome this problem, a system is proposed whereby teachers receive immediate and private feedback both individualised for each student as well as aggregated for the whole class. With that purpose, the teacher, who is equipped with a head-mounted AR display, can visualise symbols that represent the status students have stated using private devices in relation to the lecture content. In order to explore the possibilities of this approach, an experience was conducted in a lecture on a university course. The results are encouraging and suggest that as this technology matures and less intrusive AR display models become available, it could provide effective support to improve communication and interaction during lectures. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qUCkNkuAiK8","Title: Engineering the Creative Co-design of Augmented Digital Experiences with Cultural Heritage\nYear: 2015\n\nAbstract: Ubiquitous and tangible computing is opening a new panorama for interactive applications in different domains including cultural heritage. To ideate augmented experiences that provide more enjoyable, intrinsically motivating and memorable user experiences, design thinking methods that fuel the imagination and creativity of designers are required. This design can also take profit from software engineering approaches aimed at putting rationality concepts in practice. In this paper we advocate that such complex interactive (eco) systems require a mixed approach where the benefits of both disciplines are taken into account. It is not a question of design thinking versus software engineering, but a challenge to face the process both as people-values-centered and as quality-centered. This was the motivation of the CoDICE (COdesigning DIgital Cultural Encounters) software tool that supports situated, collocated and distributed tasks and adds persistence and traceability to the co-design outcomes so that the design rationale behind the products can be made explicit.","Title: A Platform for Creating Digital Educational Games as Combinations of Archetypical Games.\nYear: 2015\n\nAbstract: In this work we present a platform that allows educators to design and develop 3D Digital Educational Games (DEG) rapidly and easily. The games are described as combinations of four simple game archetypes, which can be played sequentially or simultaneously along different missions and episodes. This seeks to provide educators, with no prior knowledge on game design, with a comprehensive approach for describing educational game experiences.","Title: A See-Through Display for Interactive Museum Showcases\nYear: 2015\n\nAbstract: We present a prototype of an interactive showcase for museum exhibits that exploits a multi-touch see-through display screen. The transparent display makes it possible to superimpose an overlay of digital information while observing the physical object behind the screen. We developed an application that allows visitors to tell their experience with the object as well as to introduce comments on other visitors contributions. Our goal is to engage users in the creation of digital narratives with cultural heritage artifacts, thus constructing new layers of meaning that are parallel to the official ones provided by curators. Results from a formative study give promising feedbacks on the usefulness, novelty and attractiveness of the prototype.","Title: A Platform for Supporting the Development of Mixed Reality Environments for Educational Games\nYear: 2015\n\nAbstract: In this work we present MR-GREP, a platform that supports educators in the design and implementation of mixed reality educational games. More specifically the system allows the instructional designers to create game experiences that can be played simultaneously in an augmented reality environment as well as in a virtual space that replicates the physical space. This seeks to support the implementation of collaborative learning experiences that combine the flexibility provided by the virtual worlds with the realism and physical component that training in real scenarios allows. The development of this type of environments usually demand advanced technical knowledge that educators normally lack. The platform aims to overcome this problem by providing a set of authoring tools and applications, which does not require programming skills from the user.","Title: Inmersive End User Development for Virtual Reality.\nYear: 2016\n\nAbstract: In this paper we present VR GREP, an immersive End User Development (EUD) tool that supports authoring and modifying general purpose immersive VR environments, without having technical knowledge. The system aims to facilitate exploring the potential of immersive tools to support situated design practices.","Title: Augmenting Smart Objects for Cultural Heritage: A Usability Experiment.\nYear: 2016\n\nAbstract: In recent years the explosive growth of smartphones and the evolution of mobile communication networks have certainly revolutionized the way how people communicate and access information. This growing adoption of technology creates also some challenges. It is struggling to teach people who has had an increased exposure to technology. Cultural heritage organizations deal with this issue endlessly and look to the new technologies as an opportunity to transform and enhance the exhibition experience for matching the interest of the newest visitors. In this paper we focus on the augmented reality (AR) technologies and the role that they play to connect visitors to the modern exhibitions. Moreover, we define for the first time the concept of Augmenting Smart Object (ASO) that arises from the study of the state of the art of the AR systems applied to the cultural context and from our direct experience in a participatory design aimed at developing and evaluating an AR system for a museum exhibition.","Title: Designing Mobile Applications for Emergency Response: Citizens Acting as Human Sensors.\nYear: 2016\n\nAbstract: When an emergency occurs, citizens can be a helpful support for the operation centers involved in the response activities. As witnesses to a crisis, they initially can share updated and detailed information about what is going on. Moreover, thanks to the current technological evolution people are able to quickly and easily gather rich information and transmit it through different communication channels. Indeed, modern mobile devices embed several sensors such as GPS receivers, Wi-Fi, accelerometers or cameras that can transform users into well-equipped human sensors. For these reasons, emergency organizations and small and medium enterprises have demonstrated a growing interest in developing smart applications for reporting any exceptional circumstances. In this paper, we present a practical study about this kind of applications for identifying both limitations and common features. Based on a study of relevant existent contributions in this area and our personal direct experience in developing and evaluating emergency management solutions, our aim is to propose several findings about how to design effective and efficient mobile emergency notification applications. For this purpose we have exploited the basic sensors of modern mobile devices and the users' aptitude for using them. The evaluation consists of a practical and a theoretical part. In the practical part, we have simulated a traffic accident as closely as possible to a real scenario, with a victim lying on the ground near a car in the middle of a street. For the theoretical part, we have interviewed some emergency experts for collecting their opinions about the utility of the proposed solution. Results from this evaluation phase confirm the positive impact that EN application have for both operators' and citizens' perspective. Moreover, we collected several findings useful for future design challenges in the same area, as shown in the final redesign of the proposed application.","Title: Coproduction as an Approach to Technology-Mediated Citizen Participation in Emergency Management.\nYear: 2016\n\nAbstract: Social and mobile computing open up new possibilities for integrating citizens' information, knowledge, and social capital in emergency management (EM). This participation can improve the capacity of local agencies to respond to unexpected events by involving citizens not only as first line informants, but also as first responders. This participation could contribute to build resilient communities aware of the risks they are threatened by and able to mobilize their social capital to cope with them and, in turn, decrease the impact of threats and hazards. However for this participation to be possible organizations in charge of EM need to realize that involving citizens does not interfere with their protocols and that citizens are a valuable asset that can contribute to the EM process with specific skills and capabilities. In this paper we discuss the design challenges of using social and mobile computing to move to a more participatory EM process that starts by empowering both citizens and organizations in a coproduction service envisioned as a partnership effort. As an example, we describe a case study of a participatory design approach that involved professional EM workers and decision makers in an effort to understand the challenges of using technology-based solutions to integrate citizen skills and capabilities in their operation protocols. The case study made it possible to identify specific roles that citizens might play in a crisis or disaster and to envision scenarios were technologies could be used to integrate their skills into the EM process. In this way the paper contributes to the roles and the scenarios of theory-building about coproduction in EM services.","Title: Emergency Management and Smart Cities: Civic Engagement Through Gamification.\nYear: 2016\n\nAbstract: Nowadays, an increasing amount of cities tend to improve their community life applying smart city principles. The basic idea is to connect citizens to each other, to services, infrastructures and political and non-political organizations to take advantage of a continuous collective collaboration. In this context, the Emergency Management (EM) process becomes a critical aspect. It can exploit the citizens and organizations collaboration to reduce the risks of emergencies and the response time, to act more efficiently and with a better awareness. In this paper, we describe the redesign of an Emergency Notification (EN) application that is part of a set of applications aimed at providing citizens and organizations with easy and immediate means to cooperate. The redesign is based on Gamification and the Self-Determination Theory (SDT) principles in order to improve the user experience and foster the civic participation. The new gamified design was evaluated through an exploratory focus group involving common citizens and practitioners.","Title: Integrating user stories to inspire the co-design of digital futures for cultural heritage.\nYear: 2016\n\nAbstract: Co-design as a tactic of exploring and shaping possible futures would benefit from contributions of unwitting participants. That is, researchers gather information from them while performing some activities without participants being explicitly aware of it. We propose a platform that supports co-designers in capturing unwitting user-generated contributions and use them in the co-design of meaningful user experience for digitally augmented cultural heritage exhibitions. We report on a use case for ideating futures for cultural heritage and discuss the tradeoffs of involving unwitting participants in exploratory design as well as lessons learnt on the integration of users contributions into co-design processes.","Title: Creating Interactive and Realistic Augmented Reality Experiences.\nYear: 2016\n\nAbstract: Despite the recent advances in augmented reality (AR) technology most AR applications still fail to provide a seamless integration of the virtual objects in the augmented environment. To help alleviating this situation in this paper we propose an approach for supporting the implementation of interactive and realistic AR experiences, in which virtual objects can be occluded and collide with real ones and, in general, appear as merged into the real setting. The approach combines the use of model-based AR techniques with the advantages of current game engines, and it has been implemented using an existing game platform named GREP. We also present an experience carried out to assess the feasibility of the approach, in which more than 100 people played two AR games implemented following the proposed technique.","Title: Using combinatorial creativity to support end-user design of digital games.\nYear: 2017\n\nAbstract: To really exploit the full potential of computer games in areas other than entertainment, it will be necessary to reduce the high cost associated with their design and development and to put their production directly into the hands of the domain experts. Although these experts might be interested in integrating games in their activities, they normally do not have the required technical background to create or adapt games to their needs. We propose to tackle the complexity of game design, and thereby facilitate end user design, by defining the games as a combination of more simple games following a combinatorial creativity approach. This approach does not impose the cognitive overload of learning a new design language. In addition, it might also speed up the description of the games insofar as designers do not start from scratch, trying to match their ideas with game components, but they rely upon a set of archetypical games they can combine to reach their goals. The design technique is complemented with a game platform that offers a set of authoring tools for describing game designs that can be exported to XML files, and a game engine able to interpret such files and automatically generate a 3D virtual environment in which the games can be played. In this way, designers can envision games they will be able to design in an iterative way and play the games they design to assess their validity. The proposed combinatorial approach has been evaluated in two focus group experiences that validate its feasibility and acceptability both by technical and non-technical users.","Title: ECCE Toolkit: Prototyping Sensor-Based Interaction.\nYear: 2017\n\nAbstract: Building and exploring physical user interfaces requires high technical skills and hours of specialized work. The behavior of multiple devices with heterogeneous input/output channels and connectivity has to be programmed in a context where not only the software interface matters, but also the hardware components are critical (e.g., sensors and actuators). Prototyping physical interaction is hindered by the challenges of: (1) programming interactions among physical sensors/actuators and digital interfaces; (2) implementing functionality for different platforms in different programming languages; and (3) building custom electronic-incorporated objects. We present ECCE (Entities, Components, Couplings and Ecosystems), a toolkit for non-programmers that copes with these issues by abstracting from low-level implementations, thus lowering the complexity of prototyping small-scale, sensor-based physical interfaces to support the design process. A user evaluation provides insights and use cases of the kind of applications that can be developed with the toolkit.","Title: A Digital Knowledge Ecosystem To Increase Participation In Emergency Warnings And Alerts Management\nYear: 2017\n\nAbstract: Early warning contributes to reduce the damages when updated and reliable information is collected before a hazard happens, so that early response can be orchestrated. Integrating volunteers and citizens into data collection can help to get a better picture of the situation, since they are intelligent sensors equipped with mobile devices that can be used everywhere to collect and share information. In this paper we discuss the architecture of a digital knowledge ecosystem to support such participatory early warning process. This DKE deals with a complex knowledge coproduction problem by separating information according to its meaning, quality and reliability. The use of technological tools is aimed at supporting a self-organized, scalable and sustainable process. The different agents and interactions involved and some design requirements are drawn from a use case in the context of the Spanish early warning system.","Title: End-User Prototyping of Cross-Reality Environments.\nYear: 2017\n\nAbstract: Building physical spaces interconnected with virtual worlds is a complex task that requires high technical knowledge and hours of programming and, as a matter of fact, is relegated to the work of expert professionals. The goal of this research is to lower the development threshold through the design of an end-user toolkit that provides a visual integrated environment for the rapid prototyping of cross-reality interactions. A user study with 8 participants showed the effectiveness of our approach and uncovered design opportunities and challenges for supporting the development of cross-reality environments.","Title: A Virtual Reality Map Interface For Geographical Information Systems\nYear: 2018\n\nAbstract: The Virtual Reality (VR) technology offers new possibilities to implement Geographical Information Systems (GIS), allowing the user to visualize and interact with map interfaces in more natural and immersive way. Moreover, they can provide the user with a wide field of view similar to the one obtained when using large displays. In this paper, we present a VR application that allows the user to display and interact with a GIS map using different types of interaction modalities.","Title: Investigating Augmented Reality Support For Novice Users In Circuit Prototyping\nYear: 2018\n\nAbstract: Building an electronic circuit is an error-prone activity for novice users; many errors can occur, such as incorrect wirings or wrong component values. This work explores the use of Augmented Reality (AR) as a technology to mitigate the issues that arise when users construct circuits. We present a study that investigates the effectiveness, usability, and cognitive load of AR visual instructions for circuit prototyping tasks. A mobile-based, window-on-the-world AR tool is compared to traditional media such as paper-based or monitor-displayed electronic drawings. Results show that superimposing components and instructions through AR reduces the number of errors, allows users to easily troubleshoot them and reduces users' mental workload.","Title: A gamified platform for civic engagement in early warning.\nYear: 2018\n\nAbstract: Nowadays pervasive devices like smartphones are extremely common and people use them at any moment to share normal and exceptional circumstances through social networks. Emergency Management (EM) organizations and small and medium enterprises have demonstrated a growing interest towards this peopleu0027s inclination and are developing smart applications to report potential risks to the authorities. In this context, a continuous collaboration between citizens and EM organizations is required to provide a better service. In this work, we describe a gamified mobile platform designed to support civic participation in early warning activities.","Title: Exploring Interaction Mechanisms for Map Interfaces in Virtual Reality Environments.\nYear: 2018\n\nAbstract: Virtual Reality (VR) technologies offer new ways to visualize and use map interfaces in Geographical Information Systems (GIS). But to explore the potential benefits that this technology might provide in this context, it is necessary to deploy an affordable interaction that is both efficient and satisfactory from the usersu0027 point of view. This work aims to provide insights on how to approach the interaction design for this type of novel interfaces. We present a study comparing the usability and performance of two popular interaction strategies: body-based interaction and device-based interaction. In the first case, users controlled the map using their own body, their hands and gaze. In the second case, they managed the application using a gamepad, the Oculus Touch®. The results suggest that controlling the map using the gamepad can improve performance of the selection task, in terms of time and error rate. Also, the usersu0027 satisfaction responses for system usability favored this interaction strategy.","Title: The Immersive Bubble Chart: a Semantic and Virtual Reality Visualization for Big Data.\nYear: 2018\n\nAbstract: In this paper, we introduce the Immersive Bubble Chart, a visualization for hierarchical datasets presented in a virtual reality (VR) world. Users get immersed into the visualization and interact with the bubbles using gestures with a view to overcoming some limitations of 2D visualizations due to the capabilities and interaction affordances of the devices. The technological advances in VR give the possibility to design malleable and extensible representations and more natural and engaging interactions. Using the Oculus Touch controllers, the users can grab and move the bubbles, throw them away or bump two of them for creating a cluster. We have tested the Immersive Bubble Chart with the hierarchical clusters of semantically related terms generated from Twitter.","Title: Augmented Experiences in Cultural Spaces through Social Participation.\nYear: 2018\n\nAbstract: Technologies such as the Internet of Things (IoT) and Social Computing offer promising opportunities to envision and shape augmented experiences in a wide variety of cultural spaces. Such interactive technologies act as a hook to attract visitor's attention, but if they do not provide opportunities to engage people in a more personal and meaningful way, they can be soon discarded. Augmented experiences need to be motivating and connect with values and expectations of visitors and institutions. In a world that is becoming more and more connected and moving towards a participatory culture, the need to participate actively to co-produce knowledge and meaning can be exploited as a powerful intrinsic motivator. In this article, we describe how the Social Display Environment (SDE) promotes participation in cultural spaces whilst keeping the physical connection with the exhibition objects. The SDE makes use of Augmented Reality (AR) technology to augment physical artifacts in an exhibition with overlays of digital information that is generated by the end user (e.g., the visitor). The prototype was exhibited in a cultural center over a weekend to investigate different dynamics in terms of content generation, visitors’ interactions and perceptions with respect to the interplay of digital information and physical artifacts. The prototype was assessed as easy to learn and useful and showed potential to promote a number of meaningful social interactions around the objects involved in the exhibition.","Title: Improving Urban Environment Awareness Through Pervasive Ar Games\nYear: 2018\n\nAbstract: Augmented Reality(1) (AR) and Pervasive games can be combined to improve citizens awareness about their urban environment. While AR will provide additional information in situ, pervasive games can be used to implement playable cities that support informal learning about the environment through ludic activities performed physically in the same environment. In this paper, we present a prototype of an AR pervasive game application for an Android device that invites citizens to play and acquire knowledge about their city.","Title: Evaluating a pervasive game for urban awareness.\nYear: 2018\n\nAbstract: The combination of augmented reality and pervasive games in urban environments can be exploited to enable situated and informal learning through ludic and engaging activities. In this research, we explore how to use such technologies to improve citizensu0027 awareness about their urban environment by means of an AR pervasive game to learn about a specific urban space. Since the game is pervasively played in a physical space, many usability issues need to be assessed before evaluating whether it can engage citizens whilst promoting some sense of urban awareness. In this paper, we introduce a usability study of the application and a preliminary set of factors to be analysed to assess user engagement.","Title: Using a Google Glass-Based Classroom Feedback System to Improve Students to Teacher Communication.\nYear: 2019\n\nAbstract: The use of augmented reality (AR) to support the learning process has been extensively researched but its use to support the teaching practice has just started to be explored. In this paper, we present a communication system that makes use of a pair of Google Glass to provide the teacher with a constant and private flow of information on the students' current knowledge. The proposed system allows the information sent by the students through their mobiles to overlap with the teachers' live vision of the class. Compared to other feedback systems like clickers or backchannel systems, this AR prototype avoids teachers diverting their gaze and interrupting the class to access the students' feedback. This supports the constant monitoring of potential comprehension problems that might otherwise be overlooked. With the aim of obtaining insights on the teachers' and students' views of the system, we conducted two studies during which the system was used in real classroom settings. The results of both studies suggest that the AR system could report benefits in terms of better communication between students and teachers, and a more adequate rhythm of the class. Also, the use of the AR system in the classroom does not necessarily constitute an element, which will distract and disrupt educational activity.","Title: Do Low Cost Virtual Reality Devices Support Learning Acquisition?: A comparative study of two different VR devices\nYear: 2019\n\nAbstract: Virtual Reality (VR) can support engaging and effective learning and current VR devices commercially available are opening up opportunities and expectations in higher education. An open research question is determining whether the fidelity of the VR device (e.g. resolution, framerate, etc.) impacts learning. This work aims to address this question by conducting a study wherein the quality of the experience and the knowledge acquired using a high fidelity (and high priced) VR headset is compared against a lower fidelity (and lower priced) VR headset. The results of the study do not reveal significant difference in spatial and experiential learning. The user satisfaction and experience are also similar regardless of the headset used.","Title: Engaging Users with an AR Pervasive Game for Personal Urban Awareness\nYear: 2019\n\nAbstract: The combination of Augmented Reality (AR) and pervasive games in urban environments offers a great opportunity for learning about a specific urban environment. Since pervasive games are played in a physical space, the user familiarity with such environment might play a key role in the user motivation and in the whole user experience. In this paper, we analyse how an augmented reality pervasive game is experienced in an urban game. The aim of the game is to engage people in informal learning activities increasing their knowledge about a specific area. We also introduce the concept of Personal Urban Awareness (PUA) as a way to represent the level at which a person feels connected and knows about a specific environment. Thus, we try to find out whether the user engagement and PUA are related. In order to research this, we run an experiment where two groups of users, familiar with the environment and not familiar with it, play the augmented reality game in an urban space. The results suggest that AR pervasive games might be a good approach to engage citizens and improve their awareness about a specific area.","Title: A Tool for Monitoring and Controlling Standalone Immersive HCI Experiments\nYear: 2021\n\nAbstract: ABSTRACT We present an open source tool which provides commonly required functionality in HCI experimental research targeted at Immersive technologies. Using the tool, researchers can monitor and control a Unity scene from a controller panel running in the web-browser. Researchers can also use the tool to track the user status (e.g. see what the user sees) and trigger the execution of remote functions (e.g. alter the Unity Scene, the objects appearing, etc.). Moreover, we show a use case to exemplify how the tool is being used to support our research regarding Immersive Multisensory Interaction in a room-sized environment.","Title: Virtual-Reality Based Crisis Management Training for Teachers: An Overview of the VRTEACHER Project\nYear: 2021\n\nAbstract: The coronavirus pandemic has created an educational crisis without precedent, posed new challenges, and highlighted the need for digital skills empowerment among teachers along with the use of technology-based approaches to support the delivery of education and ensure the future of learning. As a return to normality is far from over, the implementation of novel training approaches for teacher training is more imperative than ever. In this context, this paper presents the VRTEACHER project that aims to promote the use of digital technologies and innovative and open pedagogies as part of teachers’ training methodology. The vision of the project is to empower teacher’s skills (such as empathy, perspective-taking, self-efficacy, adaptability, etc.) and readiness related to class management in crisis situations, through Virtual Reality (VR) immersive and experiential training approaches that reflect real-life scenarios and situations. The aim and challenge of the project are not just to adapt the training provided to the digital era and connect it with new technologies but to build a holistic new approach to teacher training through the use of VR.","Title: Comparing Visual Representations of Collaborative Map Interfaces for immersive Virtual Environments\nYear: 2022\n\nAbstract: Virtual reality offers unique benefits to support remote collaboration. However, the way of representing the scenario and interacting within the team can influence the effectiveness of a collaborative task. In this context, this research explores the benefits and limitations of two different visual representations of the collaboration space, shared experience and shared workspace, in the specific case of map-based collaboration. Shared experience aims at reproducing face-to-face collaboration in a realistic way whilst shared workspace translates to the virtual world the functionalities of 2D collaborative spaces. The goal is to understand whether sophisticated interfaces with realistic avatars are necessary, or if simpler solutions might be enough to support efficient collaboration. We performed a user study (n = 24, 12 pairs) through a collaborative task with two roles in a emergency crisis intervention scenario that typically uses map-based interfaces. Despite that a shared experience scenario might provide a better personal experience to the user in terms of realism, our study provides insights that suggest that a shared workspace could be a more effective way to represent the scenario and improve the collaboration."],"string":"[\n \"Title: Hci for emergencies\\nYear: 2008\\n\\nAbstract: Emergencies put people in a particular state of mind and often also in difficult physical situations. When de-signing information technology for emergencies, these two sides have to be taken into account in the various activities supporting design. This includes studying and understanding the users and the influential factors for good designs, engaging the users in the design process as well as evaluating designs in realistic ways. There are challenges specific to emergencies in all of these activities, as well as in new technologies ranging from wearable computing to distributed information systems. This workshop is meant as an opportunity for interdis-ciplinary discussion as well as practical hands-on ex-change of experiences regarding these challenges. The goal is to work towards a better understanding of the challenges, technologies, practices, and design meth-odologies relevant to HCI in emergencies.\",\n \"Title: Modeling the Dynamic Behavior of Hypermedia Applications\\nYear: 2001\\n\\nAbstract: Hypermedia applications can be defined as collections of interactive and multimedia documents that are organized as a hypertext net. The development of hypermedia applications poses specific problems, such as the need for modeling sophisticated navigational structures, interactive behaviors, and harmonic presentations involving the synchronization of contents. Moreover, the increasing popularity of Internet-based systems has put stress on the lack of mechanisms to formally specify security policies when designing hypermedia applications. Traditional design models and methodologies are not suitable for hypermedia applications and the up-to-now developed hypermedia-oriented models do not cover the whole set of design needs. In this context, we present Labyrinth, a hypermedia-oriented model providing formal elements to describe the static structure and dynamic behavior of this kind of nonlinear, multisensory, and interactive applications.\",\n \"Title: A Methodological Approach to Encourage the Service-Oriented Learning Systems Development.\\nYear: 2009\\n\\nAbstract: The basic idea of service-oriented learning is that a learning environment should be conceived as a set of independent units of learning packaged as learning services. The design, development and deployment of a learning system based on integrating different learning services needs both a technological platform to support the system as well as a methodology that manages the development process. Such technological platform is provided by the Service-Oriented Learning Architecture (SOLA). SOLA proposes an architecture style, which defines how to deploy several units of packeged-learning services. The purpose of this paper is to review the SOLA concept and to present a specific method based on specifying instructional domains, to complement the SOLA approach. Our method suggests the definition of a feature model, which represents the characteristics of the instructional domain, in order to address the identification and clasiffication of candidate services. The approach here proposed facilitates the definition of candidate-learning services in order to enhance the integration of such services.\",\n \"Title: Towards efficient web engineering approaches through flexible process models\\nYear: 2007\\n\\nAbstract: After more than a decade of web developments and some deafening fiascos, it has become clear that it is not possible to face the development of large scale web systems without following a systematic and well-defined process to guarantee quality, measurability, maintainability and reusability. There are a number of hypermedia/web engineering methods that provide mechanisms to specify the product requirements, including those concerning structure, navigation, interaction, presentation and access. But apart from product requirements there are also process requirements which in the web arena are constantly changing. Hence, to be put in practice without disturbing the project goals nor compromising its success, methods have to rely on empirical and flexible process models that can be easily adapted to fit process requirements. Little attention has been paid to the process model in most hypermedia/web methods which usually apply a classical iterative process based on the use of prototypes that are tested with users. In this paper we describe how we did apply the ADM web engineering method following a flexible star life cycle in the context of a specific web project highlighting the main benefits of this approach. In particular we will describe the different cycles applied in the ARCE project, illustrating the application of a usability engineering life cycle in a real case.\",\n \"Title: A Literature-Based Approach To Annotation And Browsing Of Web Resources\\nYear: 2003\\n\\nAbstract: The emerging Semantic Web technologies critically depend on the availability of shared knowledge representations called ontologies, which are intended to encode consensual knowledge about specific domains; Currently, the proposed processes for building and maintaining those ontologies entail the joint effort of groups of representative domain experts, which can be expensive in terms of co-ordination and in terms of time to reach consensus. In this paper, literature-based ontologies, which can be initially developed by a single expert and maintained continuously; are proposed as preliminary alternatives to group-generated domain ontologies, or as early versions of them. These ontologies encode domain knowledge in the form of terms and relations along with the (formal or informal) bibliographical resources that define or deal with them, which makes them specially useful for domains in which a common terminology or jargon is not soundly established. A general-purpose metamodelling framework for literature-based ontologies - which has been used in two concrete domains - is described, along with a proposed methodology and a specific resource annotation approach. In addition, the implementation of a RDF-based Web resource browser - that uses the ontologies to guide the user in the exploration of a corpus of digital resources- is presented as a proof of concept.\",\n \"Title: Meta-design blueprints: principles and guidelines for co-design in virtual environments\\nYear: 2011\\n\\nAbstract: Meta-design is defined as a conceptual framework that allows endusers to create contents by using socio-technological infrastructures in which people can actively participate. Despite the fact that the foundations for metadesign are well known, it is still an abstract concept lacking of suitable design artifacts to guide its application. The aim of this paper is to analyze the concept of meta-design in order to define blueprints for its application in web-based environments. Based on a review of both literature and websites conceived to design contents by users, the paper compiles a number of guidelines to address the development of web tools that support meta-design.\",\n \"Title: Light on horizontal interactive surfaces: Input space for tabletop computing\\nYear: 2014\\n\\nAbstract: In the last 25 years we have witnessed the rise and growth of interactive tabletop research, both in academic and in industrial settings. The rising demand for the digital support of human activities motivated the need to bring computational power to table surfaces. In this article, we review the state of the art of tabletop computing, highlighting core aspects that frame the input space of interactive tabletops: (a) developments in hardware technologies that have caused the proliferation of interactive horizontal surfaces and (b) issues related to new classes of interaction modalities (multitouch, tangible, and touchless). A classification is presented that aims to give a detailed view of the current development of this research area and define opportunities and challenges for novel touch- and gesture-based interactions between the human and the surrounding computational environment.\",\n \"Title: Integrating RBAC Mechanisms in a Web Server\\nYear: 2003\\n\\nAbstract: ABSTRACT Hypermedia systems (whether web sites or not) should support multilevel policiesm, offering different views and manipulation abilities of the same information to users with different needs in a particular context. Several experiences have demonstrated that role-based access control (RBAC) policies are a powerful mechanism to simplify management tasks. This paper describes the implementation and the integration in the Apache server of the MARAH model, that provides security designers with mechanisms to specify security rules using elements and abstractions of the hypermedia domain (such as nodes, links or contents), considering a web site as a special case of hypermedia. KEYWORDS Hypermedia, security models, role-based access control, web server. 1. INTRODUCTION Hypermedia systems should support multilevel policies in order to offer different views and manipulation abilities of the same information to users with different needs and responsibilities in a particular context [Diaz01]. The assignment of authorizations in terms of users or groups is a unmanageable, laborious and prone to error task, so that role based access control (RBAC) appears as an useful approach to simplify this management [Ferraiolo92], [Sandhu96]. RBAC is a security mechanism that regulate access to resources through organizational entities called roles [Jansen98]. High-level security models make possible to specify the rules that control the access to a specific system, but this specification can be faced from rather different levels of abstraction. MARAH (Role-Based Access Model for Hypermedial Architectures in Spanish) is a high level security model for hypermedia, that tries to fill in the conceptual gap between the application domain and the underlying hypermedia platform (e.g. web) that supports it. MARAH considers three layers in the hypermedia application security design. The top one is called\",\n \"Title: Un servicio web de políticas de acceso basadas en roles para hipermedia\\nYear: 2005\\n\\nAbstract: High level security is a key requirement in hypermedia/web applications. The systems opening to the Internet makes the research effort to move towards protecting the information transmission (i.e. SOAP messages, policy descriptions,…), but little attention is paid to what the user can do with the system. Role-based access control (RBAC) allows to formulate the organization's resource access policy...\",\n \"Title: Designing the Execution of Learning Activities in Complex Learning Processes Using LPCEL\\nYear: 2006\\n\\nAbstract: The contemporary education has begun to observe constructivist position as important in understanding diversity in education. Instructional design on technology (IDT) presents important challenges to integrate principles, models and techniques inspired by this new perspective emerging in educational technology. The complex learning process (CLP) is a vision that can be suitable to facilitate this aim. In order to face these challenges, it is essential to integrate new technology-supported learning. Our vision is focused on the development of learning process composition and execution languages (LPCEL), which can facilitate the design, composition and execution of CLP. This work presents an overview of LPCEL specification, so that it can be a reference for the development of related technologies.\",\n \"Title: Towards an effective evaluation framework for IMS LD-based didactic materials: criteria and measures\\nYear: 2007\\n\\nAbstract: Evaluation is one of the most important activities in the didactic materials development process since it allows developers to check if the obtained material satisfies all requirements and it also provides developers with reliable information about material's utility, validating if the obtained material can be effective support in the achievement of the educational goals which it intends to support. Evaluation results provide valuable information for the material redesign in such cases when the requirements or educational goals are not satisfied. Nevertheless its importance, the evaluation has been often neglected in most of the approaches related to the development of didactic materials, which are more focused on issues such as interoperability or reusability. In this paper we present the MD2 evaluation framework based on a general evaluation procedure that include a set of criteria and measures for the two more important evaluation objectives of IMS LD-based didactic material: its usability and pedagogical usefulness.\",\n \"Title: Meeting the needs of teachers and students within the CESAR training system\\nYear: 1998\\n\\nAbstract: Computers seem to be an unquestionably useful tool to support the learning process, although positive students' and teachers' attitude towards the system is required to guarantee a successful introduction of new technologies in traditional classrooms, Training or exercises provide the students with the challenge of using their knowledge to solve concrete problems, so that they incite students to participate actively, Training can be adapted to different learning styles in order to strengthen student involvement. Moreover, tools to adapt the didactic material to several educational methods must be provided, in such a way that teachers consider the system a helpful tool rather than a substitute, Taking into account the foregoing, this paper describes a training system to create and use exercises in a hypermedia learning environment for hearing-impaired children called CESAR.\",\n \"Title: Agent-based adaptive selection and interaction to Z39.50 servers\\nYear: 2000\\n\\nAbstract: Digital libraries and OPACs offer an enormous collection of information resources which can be accessed through the Internet by quite different users thanks to the existence of standard protocols for information retrieval such as Z39.50. However, some users may have difficulty in getting the items they are looking for in such a huge volume of heterogeneous resources since they have to know where and how they have to search. Thus, one of the main reasons for disregarding the Z39.50 service has traditionally been the absence of appropriate interfaces and the cost of making alternative searches. WAY-Z39.50 tries to help spread the use of these servers by providing easy Web access to them, as well as facilitating access to multiple servers at once. The prototype implements the general WAY model based on an agent-based architecture that provides adaptive searching in different servers using an adaptive interface as well\",\n \"Title: ECCE toolkit: prototyping UbiComp device ecologies\\nYear: 2014\\n\\nAbstract: The tremendous amount of different input devices and interactive environments envisioned by researchers produces a severe challenge for the development of ubiquitous interaction. Toolkits that support the rapid setup of ubiquitous environments reduce the effort in arranging the technological medium and have the potential to lower prerequisite knowledge and automate low-level programming tasks. In this paper, we present our work-in-progress approach: a toolkit that combines physical and digital components into a unique environment to allow the rapid setup of device ecologies.\",\n \"Title: Generation of Personalized Web Courses Using RBAC\\nYear: 2002\\n\\nAbstract: Role-based access control policies model the users domain by means of complex structures where the roles assumed by the users are specialized into more concrete subroles which inherit properties and authorizations from their parents. In this paper, we describe how to combine these principles and adaptation to provide personalized access to the different types of users of a web-based course. We also present Courba, a platform that generates personalized web-based courses using XML to support the definition of access policies.\",\n \"Title: Validation of critical parameters for predictive evaluation of notification system in avionics interfaces\\nYear: 2007\\n\\nAbstract: The evaluation of notification systems is rare in critical systems. The only available experiences are based on empirical data on costly simulated environments and the subjective follow-up of some guidebooks probed by the experience. In case of absence of performance requirements, critical parameters can provide quantitative measures that may be used to determine the overall usability of interfaces that continuously present precious information (id est. Notification Systems) in Avionics (NSA) and should be validated before use to improve the confidence level in the measurement unit. In this paper, we introduce a set of critical parameters that could be used for usability evaluation of NSA's interfaces. A process for a formal validation is described and results of the applicability of these parameters to the real NSA interface of A400M's power plant are presented.\",\n \"Title: Labyrinth, an abstract model for hypermedia applications. Description of its static components\\nYear: 1997\\n\\nAbstract: In information technology, models are abstract devices to represent the components and functions of software applications. When a model is general and consistent, it represents a useful design tool to unambiguously describe the application. Traditional models are not suitable for the design of hypermedia systems and, therefore, specific design models and methodologies are needed. In the present article, the requirements for such models are analysed, an overview of the characteristics of the existing models for hypermedia applications is made and an abstract model fulfilling the analysed requirements is presented. The model, called Labyrinth, allows 1) the design of platform-independent hypermedia applications; 2) the categorisation, generalisation and abstraction of sparse unstructured heterogeneous information in multiple and interconnected levels; 3) the creation of personalisations (personal views) in multiuser hyperdocuments for both groups and individual users and 4) the design of advanced security mechanisms for hypermedia applications.\",\n \"Title: Uses of Augmented Reality for Supporting Educational Presentations\\nYear: 2013\\n\\nAbstract: This work aims to explore the benefits and potential uses of Augmented Reality technology for supporting communication in lectures and presentations. In this paper we present the architecture and implementation of an Augmented Presentation Feedback System (APFs). The system allows a speaker equipped with an Augmented Reality Head-Mounted Display to visualize visual cues depicted over the listeners' heads. These can be used as a way of providing the speaker with continuous, private and immediate feedback on her explanations, so she can adapt the content and pace of the explanation to the specific needs of the listener and improve the flow of the presentation.\",\n \"Title: A design toolkit for hypermedia applications\\nYear: 2003\\n\\nAbstract: The development process of hypermedia applications involves a variety of users with different levels of knowledge and skills. In order to get a good communication among participants, a graphical toolkit based on a method facilitates this work. In this paper, we present a design environment, Ariadne Tool, that allows a designer to model a hypermedia application, to validate such a design and to generate dynamically XML + SMIL implementation templates. This environment is based upon the Ariadne Method which offers a set of integrated activities to model hypermedia applications in a systematic and iterative way.\",\n \"Title: Evaluation of Hypermedia Educational Systems: Criteria and Imperfect Measures\\nYear: 2002\\n\\nAbstract: Educational systems have to be assessed to determine whether their user interface, didactic method, instructional materials and interaction mechanisms help users reach their learning and teaching goals. With this purpose, educational developers need to rely on a set of clear, concrete and measurable quality criteria. In this paper, we propose an evaluation framework made up of a number of criteria to test the utility and usability of educational hypermedia systems. We also discuss that measuring these criteria entails different forms of imprecision and uncertainty, that call for the user of representation formalisms like fuzzy set theory. Theframework presented here is aimed not only at helping educational developers to evaluate their systems, but also to provide them with some guidance to address educational requirements during the design process.\",\n \"Title: Achieving shared understanding in face-to-face 'tabletop' exercises\\nYear: 2013\\n\\nAbstract: Shared understanding plays a key role within the emergency-planning context to successfully develop planning tasks. Particularly in 'tabletop' exercises, such an understanding is required to make decisions about planning. However, as the task progresses, the amount of relevant knowledge that a planner can remember about the task progressively decreases. This fact can impose a limit on the task progress. With the purpose of overcoming such a limitation, this work presents a computer-based face-to-face collaborative tool aimed at supporting 'tabletop' exercises.\",\n \"Title: Ariadne, a Development Method for Hypermedia\\nYear: 2001\\n\\nAbstract: Hypermedia development poses very specific problems such as the need for mechanisms to model sophisticated navigational structures, interactive behaviours and usable multimedia compositions. Moreover, since the majority of hypermedia applications are accessed by different users, security becomes a key feature. In this context, we present a development method called Ariadne which offers a number of tools to create hypermedia applications in an progressive and integrated way.\",\n \"Title: Toward Hypermedia Design Methods for the Semantic Web\\nYear: 2003\\n\\nAbstract: Hypermedia design methods have been proposed for thedevelopment of hypermedia and web applications. Nowadays,we face up to another challenge, the Semantic Web,in order to represent web resources in a structured, logicaland semantic way. Therefore, hypermedia design methodswill have to provide semantic contents and contextual informationabout application domain during the developmentprocess of web applications. In this paper, we propose toaccomplish that including ontologies within the conceptualmodeling of hypermedia applications.\",\n \"Title: SocialStory: a social storyboard system for sharing experiences in emergencies\\nYear: 2012\\n\\nAbstract: During and after crisis situations people are interested in getting knowledge about what happened and in obtaining information regarding damages, victims, and possible repercussions. Social network systems represent powerful sources due to their rapid growth in the last few years and the amount of continuous updated information published by people. Studies confirmed that people are interested in reporting facts during hazards, however due to the wide distribution of information and the lack of mechanisms to re-use it, it is an awkward task to be accomplished. For the above reasons in this paper we present SocialStory, a social platform for helping people to retrieve and filter materials available on the Internet and to compose and share personal experiences about crisis situations.\",\n \"Title: End-user oriented strategies to facilitate multi-organizational adoption of emergency management information systems\\nYear: 2010\\n\\nAbstract: Response to large-scale emergencies is a cooperative process that requires the active and coordinated participation of a variety of functionally independent agencies operating in adjacent regions. In practice, this essential cooperation is sometimes not attained or is reduced due to poor information sharing, non-fluent communication flows, and lack of coordination. We report an empirical study of IT-mediated cooperation among Spanish response agencies and we describe the challenges of adoption, information sharing, communication flows, and coordination among agencies that do not share a unity of command. We analyze three strategies aimed at supporting acceptance and surmounting political, organizational and personal distrust or skepticism: participatory design, advanced collaborative tools inducing cognitive absorption, and end-user communities of practice.\",\n \"Title: A semantic representation for domain-specific patterns\\nYear: 2004\\n\\nAbstract: Design patterns are a valuable mechanism to capture and disseminate best practice in software design. The oft-cited definition of an Alexandrian pattern, “a solution to a problem in a context”, stimulates the definition of patterns from knowledge and expertise in any domain. Indeed, their application has spread from the object-oriented community, who first adopted them, through different software areas including human-computer interaction, virtual environments, ubiquitous computing, hypermedia and web engineering. This kind of patterns that describe successful solutions to recurring design problems in terms of a specific domain of application are known as domain-specific patterns. The increasing number of available design patterns is making difficult to find the most appropriate one given a specific problem since this task requires mastery on existing design patterns. Hence, there is a need to introduce a formalism to describe them accurately and to allow a rigorous reasoning process to assist users to retrieve those patterns that solve their problems. With this purpose, we propose a semantic representation for domain-specific patterns based on the domain knowledge for which they were written and for which an ontology-based approach is applied. This representation is used as an underlying armature for complementing the informal textual pattern description by means of semantic annotations. The combination of the literary pattern representation with its formal representation counterpart could assist an intelligent search engine that supports users not just for retrieval purposes but also for the discovery useful design solutions improving, therefore, their ability to develop quality software.\",\n \"Title: Making Semantic Web based-hypermedia Applications\\nYear: 2005\\n\\nAbstract: The existence of web pages that are described semanti- cally via ontologies and metadata conforming to these on- tologies is crucial to bring the Semantic Web to life. In this paper we address the problem of developing semantic web- based hypermedia applications through web-hypermedia design methods. For that, we propose a general approach based on extracting an ontology-based design from a tra- ditional model-driven design , thus allowing hypermedia designers to obtain both domain ontologies and annotated documents in parallel with the application design without requiring extra tasks and expert know-how. This approach is presented through a specific hypermedia design method called Ariadne Development Method (ADM) and its soft- ware tool, AriadneTool, that automates a semantic extrac- tion process to provide annotated documents in a format suitable for the semantic web, as RDFS and RDF. Moreover, a semantic web platform has been developed in order to enable the publication of the resulting semantic web-based hypermedia application.\",\n \"Title: MUTO: the modular unified tagging ontology\\nYear: 2011\\n\\nAbstract: Tagging has become a popular indexing method within the last years and can be considered one of the cornerstones of the Social Web. Several ontologies have been developed that aim to formally describe tagging and folksonomies in order to improve their interoperability and processability. However, each of these ontologies covers different aspects of the domain; finding the right ontology for a certain purpose and aligning it correctly with other ontologies is difficult. This paper critically reviews available tagging ontologies and presents a unified vocabulary that combines the 'best of' these ontologies in one consistent schema. A central goal was to ensure high concept reuse by simultaneously avoiding redundancies. A modular design was chosen to reduce complexity and prevent inconsistencies. It groups the different elements of tagging and separates advanced concepts from the core ontology. Key design decisions are justified and modeling alternatives are discussed, not only to explain the unified ontology but also to contribute to a better understanding of the conceptual space of tagging and folksonomies.\",\n \"Title: Envisioning The Transformative Role Of It In Lectures\\nYear: 2012\\n\\nAbstract: One of the most widely used methods for teaching is the lecture. During the last few decades lecturers and students have taken advantage of the progressive introduction of new technology for supporting these lectures. As this trend is very likely to continue, in this paper we will try to anticipate some possible technology enriched future lecture scenarios. We also present ALFs, a system which aims to improve the communication between participants in a lecture making use of augmented reality techniques.\",\n \"Title: Advanced Transactional Models for a New Generation of Educational Modelling Language Engines\\nYear: 2009\\n\\nAbstract: E-Learning Systems have evolved moving from self-contained simple static contents, to the design and execution of learning scenarios described by Educational Modelling Languages (EML) and the integration of web services. But also carrying with implications such as dealing with long-lived learning activities and finishing activities without accomplishing their learning objectives. Advanced Transactional Models (ATM) relax some of the basic ACID transaction properties so applications may handle in a reliable way, several types of long-lived activities and compensation activities. An EML execution engine must implement different ATMs in order to provide different levels of transaction support to deal with the diverse types of learning activities.\",\n \"Title: Instinctive Game Enviroment: Exploring the Application of Natural Interfaces for Supporting Game-Based Learning\\nYear: 2012\\n\\nAbstract: The application of computer games for learning is a field of growing interest in the education community. Games have proved to be a useful resource to teach concepts, expand perceptions, or develop skills. Typically, young children make use of recognition pattern games. This kind of games helps children to improve their knowledge and recognition skills. However, these games require someone to control the process of the game and provide feedback to the child. This paper presents a game environment based on applying the principles of natural interfaces to the development of education computer games. After realizing the proof-of-concept, we could observe that this environment allows children to interact with the games in an instinctive way seamlessly.\",\n \"Title: CoDICE: balancing software engineering and creativity in the co-design of digital encounters with cultural heritage\\nYear: 2014\\n\\nAbstract: Software engineering analysis and design methods are mainly guided by objective principles and criteria, whilst design thinking is usually fueled by subjective and people-based criteria like emotions, aesthetics or cultural and personal resonance. Complex interactive systems require a mixed approach where the benefits of both disciplines are respected: engineering and creativity, rationality and emotions, quality-centered and people-centered. This is the main purpose of a software tool, named CoDICE (COdesigning DIgital Cultural Encounters), that is being developed within the meSch EU project that is aimed at co-designing smart objects for enhanced encounters with cultural heritage. CoDICE adds persistence and traceability to the co-design activities and makes it possible to extend ideas discussion beyond collocated meetings. It also provides mechanisms to revisit design products and generate informed design rationale.\",\n \"Title: I feel lucky: an automated personal assistant for smartphones\\nYear: 2012\\n\\nAbstract: Third generation devices, such as smartphones, have the possibility of knowing the position of the user. By combining time, position and data in the Cloud it is possible to make smart deductions as to what information the user needs. These deductions can be performed by an automated assistant that have access to the user's e-mail and SMS messages, calendar, phone book, notes, etc., as well as to the position of the user. The assistant can present the information in an \\\"I feel lucky\\\" display on the user's smartphone. These concepts have been evaluated in a case study with a group of students, simulating the output of such an interface.\",\n \"Title: A Meta-modeling based Approach for the Multi-Disciplinary Design of Web Educational Systems\\nYear: 2009\\n\\nAbstract: Multi-disciplinary teams might provide a multi-faceted perspective of web educational systems that integrates experience from different fields. Each expert has a view of the system and she uses domain specific languages in order to express solutions to the problems she is concerned with. In this way, the final system can be seen as a combination of a number of complementary views, each of which focuses on problems of a different nature. However, such views are expressed with different specification tools so that they have to be integrated to produce a common design that is complete and consistent. Creating a common language encompassing multi-disciplinary design views is a challenging endeavor but it might impose a cognitive overload to each member of the group who is exposed to unfamiliar concepts of other disciplines in her design view. Alternatively, this paper describes an approach called MODUWEB that consists of letting each designer use the tool she is proficient in for her design tasks and then complementary design perspectives are integrated using meta-modeling techniques. MODUWEB also includes a number of constraints and semantic rules that guarantee the completeness and consistency of the resulting model.\",\n \"Title: Improving communication for mobile devices in disaster response\\nYear: 2007\\n\\nAbstract: During disaster response, networks can become overloaded and are susceptible to complete failure in the disaster area. This disables mobile communication, hindering response efforts from mobile users. Mobile users make use of various heterogeneous devices and require infrastructure to facilitate the communication of distributed information. Communication flow among mobile users is disorganized as it is either too strong and hierarchical or too flexible and dynamic. We have designed ubiquitous mobile infrastructures to match the response environment's communication flows and telecommunications, and produced a ubiquitous mobile communication system (ubimobcom). The design standardizes the information exchanges between mobile users. In this paper, we show that ubimobcom makes cooperation and coordination among mobile users possible at the disaster. Using ubimobcom, mobile users can be coordinated and can cooperate in outdoor areas, besides; they can continue connected with their disaster operation center. We describe the ubimobcom system to illustrate the use of communication by mobile users to disasters that may range from minor to catastrophic.\",\n \"Title: Don't touch me: multi-user annotations on a map in large display environments\\nYear: 2010\\n\\nAbstract: Touchless interaction techniques do not require physical contact while interacting with a system so to allow natural interaction with digital information, made tangible in the physical world through pervasive screen displays. In this project we explore the use of Nintendo Wii Remote controller as a touchless interface for interacting with map based applications in large displays environments. A prototype (Don't Touch Me) was developed that allows users to collaborative place multimodal annotations on a map: pictorials, auditives and haptics.\",\n \"Title: Integrating Ontologies into the Collaborative Authoring of Learning Objects\\nYear: 2005\\n\\nAbstract: Authoring learning material is a multi-disciplinary undertaking where different people can play their role. Any support that can be provided for the collaboration of instructional designers, pedagogues, media designers, and students, among others, is welcome. In particular, metadata annotation of learning objects is an important task within the whole authoring process. This work presents the first resulting products and approaches from the MD2 project, consisting of a service-oriented framework and a tool to support the integrated, ontology-based collaborative annotation of learning objects.\",\n \"Title: EML Learning Flow Expressiveness Evaluation\\nYear: 2009\\n\\nAbstract: Educational Modelling Languages such as IMS LD, LAMS and LPCEL can be used to describe a learning process, but they depict different degrees of expressiveness to represent learning flows. This paper presents an evaluation of the expressiveness of these languages based over the analysis of different workflow control patterns including basic control flow, advanced branching and synchronization, and iteration; outlining the learning process design issues.\",\n \"Title: Integrating Algorithm Visualization Video into a First-Year Algorithm and Data Structure Course.\\nYear: 2012\\n\\nAbstract: In this paper we describe the results that we have obtained while integrating algorithm visualization (AV) movies (strongly tightened with the other teaching material), within a first-year undergraduate course on algorithms and data structures. Our experimental results seem to support the hypothesis that making these movies available significantly improved students' performances. Moreover, the movies were highly appreciated by the students (both from a comprehensibility point of view and from a usefulness point of view), even though with a low attitude towards the emerging video pod-cast technology. Finally, our results indicate the necessity of integrating the AV movies with audio comment, which seems to be one of the most interesting research question left open by our study.\",\n \"Title: Fuzzy Linguistic Summaries in Rule-Based Adaptive Hypermedia Systems\\nYear: 2002\\n\\nAbstract: Rule-based adaptive hypermedia systems personalize the structure of the hypermedia space using an inference mechanism that operates on a specific knowledge representation about its users. Approximate quantifiers are very frequently used in human language expressions that entail the summarization of a large number of facts. We describe how quantified expressions can be used in adaptation rules to specify common adaptation behaviors, enhancing rule's expressive power for the human expert. Those quantified expressions can be implemented through fuzzy quantification mechanisms operating on fuzzy linguistic labels and relations, and can be integrated as extensions in general-purpose rule-based adaptive hypermedia systems.\",\n \"Title: Applying software engineering methods for hypermedia systems\\nYear: 2001\\n\\nAbstract: Despite the existence of software engineering methods for hypermedia development, this process is not as systematic as it could be expected and, in fact, the \\\"hypermedia software crisis\\\" still remains. This situation can be attributed to the scarce dissemination of methods for hypermedia. In this context, we present our experience teaching a software engineering method for hypermedia, called Ariadne, which is used to develop hypermedia applications following a user-centered approach.\",\n \"Title: A Virtual Environment for Learning Aiport Emergency Management Protocols\\nYear: 2009\\n\\nAbstract: This paper presents a virtual environment designed to enhance the learning of airport emergency management protocols. The learning is performed in an informal manner, with each learner playing a different role in a particular emergency simulation. Learners interact within the virtual environment, managing the available information and following the steps prescribed for each type of emergency in the Airport Emergency Plan of the Spanish Civil Defence Organization. The simulation can be run in different modes of difficulty, and can be used as a learning tool as well as an evaluation tool to measure the accuracy of the learner's actuation within the protocol. It can also support stand-alone training having some of the emergency roles played out by the computer. The virtual environment has been built using DimensioneX, an open source multi-player online game engine.\",\n \"Title: Comparison of knowledge during the assembly process of learning objects\\nYear: 2010\\n\\nAbstract: This paper describes the conceptual framework OntoGlue for the assembly of learning objects (LOs). To permit a coherent assembling process from the point of view of requirements and competencies, OntoGlue enhances the definition of LOs by including associated knowledge (i.e. requirements and competencies) in their conceptual data schema. This associated knowledge is defined in terms of classes of educational ontologies (used as taxonomies), possibly related by mappings. There are several advantages associated with the OntoGlue approach. Firstly, it provides an enhanced description of the LOs, which permits their search and reuse by considering requirements and competencies. Secondly, during the assembly process of two LOs, OntoGlue checks that the competencies of the first LO cover the requirements of the second LO, guaranteeing a coherent assembling process from the requirements and competencies' point of view. Thirdly, OntoGlue automatically calculates the meta-data of the resulting assembled LO. Finally, the definition of the associated knowledge in terms of classes of ontologies, possibly related by mappings, permits an advanced comparison of requirements and competencies during assembly and search processes.\",\n \"Title: An Architectural Framework for Composition and Execution of Complex Learning Processes\\nYear: 2005\\n\\nAbstract: A complex learning process (CLP) is understood as the result of the dynamic and unanticipated integration of diverse pedagogical approaches in a learning process, based on the collaboration between instructors and learners. Educational modeling languages are used to specify and design learning processes that can be adaptable to the demands of a particular pedagogical context. Based upon IMS service-oriented architectural principles, a framework for learning process composition and execution is presented. The objective of that framework is to enable the dynamic and unanticipated composition of distributed learning services. This is guided by a case study of how this framework can be implemented in a complex learning scenario.\",\n \"Title: The role of evaluation in an effective development of didactic materials: The MD2 approach\\nYear: 2007\\n\\nAbstract: Evaluation is one of the most important activities in the didactic materials development since it allows developers to check if the properties of obtained material satisfy all the requirements established at begin of its development and if that material can be an effective support to achieve the educational goals of any instructional situation. Its results are crucial data for the material redesign in such cases when those requirements or educational goals are not satisfied. Here we describe our vision of evaluation in the MD2 development approach that proposes to assess the didactic materials based on their pedagogical utility and usability.\",\n \"Title: A Grid-based Architectural Framework for Composition and Execution of Complex Learning Processes\\nYear: 2008\\n\\nAbstract: Through the past two decades, education in computer and information science and technology (CISE) has moved toward a model that pervasively incorporates programming projects and other engaging student activity. Realistic activities and materials are ...\",\n \"Title: LEARNING LINKS: Reusable Assets with Support for Vagueness and Ontology-Based Typing\\nYear: 2002\\n\\nAbstract: Existing approaches to ontological support in courseware are focused on the annotation of hypermedia nodes or contents, while links are described only by classifying them into a set of predefined types. In this work, we describe the concept of Learning-Link as an independent and reusable learning resource that can be annotated with terms defined in a link ontology. The computational semantics of that ontology, combined with fuzziness to specify gradedrelations, enables the implementation of extended adaptive behaviors that entail inferences and approximate reasoning.\",\n \"Title: Participative Knowledge Production Of Learning Objects For E-Books\\nYear: 2002\\n\\nAbstract: In a distributed learning environment, the development of learning objects is a participative task. We consider learning objects as knowledge pieces, which are subject to the management processes of acquisition, delivery, creation and production. A multiple-tier architecture for participative knowledge production tasks is introduced, where knowledge-producing agents are arranged into knowledge domains or marts, and a distributed interaction protocol is used to consolidate knowledge that is produced in a mart. Knowledge consolidated in a given mart can be in turn negotiated in higher-level foreign marts. The proposed architecture and protocol are applied to coordinate the authoring of open e-book packages as learning objects by a distributed group of authors.\",\n \"Title: Modelling Static and Dynamic Aspects of Hypermedia Systems\\nYear: 1997\\n\\nAbstract: The static and dynamic properties of the Labyrinth model, used for the definition and management of hypermedia applications, are presented in this paper. The most relevant characteristics of Labyrinth are the following: the structure of applications can be modelled by means of composite objects; the reactive nature and temporal dimension of multimedia contents are considered; and security policies to preserve information confidentiality and integrity can be defined\",\n \"Title: Digitally augmented narratives for physical artifacts\\nYear: 2014\\n\\nAbstract: In this working paper we present the design and setup of a workshop environment that empowers users with tools to create and share digital narratives associated with physical artifacts. The approach focuses on two main design choices: (1) physical embodiment, by having people directly interact with the physical objects we want to augment and, (2) situated social interactions, by offering the possibility to share personal ideas and comment on others, to collaboratively produce stories about augmented objects. We also report about the main evaluation results we got in a workshop in which we studied users needs with respect to tangible interactive experiences in exhibitions of museums.\",\n \"Title: Prototyping device ecologies: physical to digital and viceversa\\nYear: 2014\\n\\nAbstract: This Studio will involve participants creating interactions with physical and digital elements. They will have the opportunity to use a toolkit we developed that combines physical and digital widgets into a unique environment to allow the rapid setup of device ecologies. Therefore, participants will be able to explore how the toolkit support to physical/digital interaction gives people with low, when no, technical skills the possibility to rapidly prototype interactions among heterogeneous devices, thus blurring the boundaries between the physical and the digital world. The Studio is structured in two parts: in the first one, participants will get familiar with the toolkit hardware and software functionalities. In the second part they will experiment directly the toolkit capabilities by developing interactions among digitally-augmented objects in a cultural heritage context. We expect, in this Studio, people to learn what are the possibilities and challenges in the development of device ecologies.\",\n \"Title: Evaluating the Runtime Adaptation of EML-Described Learning Processes\\nYear: 2008\\n\\nAbstract: This work aims to provide the instructors of learning process specified by means of an educational language (EML) with a mechanism to modify the process definition during runtime. The paper presents the results of some experiments carried out as part of the evaluation of the envisaged solution. The core ofthe proposed solution is a model which allows the instructor to describe variations of the original learning process design, as well as to evaluate and monitor the process progress. The model is complemented with a method which organizes the performance of the instructor actions supported by the model, and a mechanism to allow its application on running instances of the process. To state the suitability of the proposed method and the expressivity of the adaptation model, the solution has been applied on three different scenarios. Three real learning processes supported on Moodle platforms have been replicated on Unit of Learning (UoL) versions described by means of IMS Learning Design(IMS LD). The adaptations and monitorizations performed by the instructors in the Moodle versions have been described using the adaptation model elements and applied to UoLs following the proposed method guidelines.\",\n \"Title: Studying social technologies and communities of volunteers in emergency management\\nYear: 2013\\n\\nAbstract: Communities of volunteers are fundamental agents in the emergency management process. In spite of the unquestionable value that social technologies could bring to such communities of volunteers it is not clear whether they are exploiting all their potential and why. This work presents a qualitative study with volunteers from different emergency communities with the purpose of establishing design challenges to better leverage social technologies that can augment the capabilities of such communities. The results of the study suggest the need to address specific design challenges related to reliability, integrity, and efficient analysis of information. In addition, the integration of multiple interaction mechanisms and shared calendars as well as the design of effective and adaptive messages for crisis communications are also considered important aspects by emergency volunteers.\",\n \"Title: A transformation-driven approach to the verification of security policies in web designs\\nYear: 2007\\n\\nAbstract: In this paper, we present a verification framework for security policies of Web designs. The framework is based on the transformation of the models that conform the system design into a formalism where further analysis can be performed. The transformation is specified as a triple graph transformation system, which in addition creates mappings between the elements in the source and target models. This allows the back-annotation of the analysis results to the original model by means of triple graphical patterns. The verification mechanisms are provided by the designer of the Web design language, together with the language specification. However, the complexities of the formalisms are hidden to the developer who uses the language. As case study, we apply these ideas to Labyrinth, a domain specific language oriented to the design of Web applications. The analysis is done by a transformation into the Petri nets formalism, and then performing model checking on the coverability graph. The framework is supported by the meta-modelling tool AToM3.\",\n \"Title: Visual tag authoring: picture extraction via localized, collaborative tagging\\nYear: 2008\\n\\nAbstract: In this work we present a system to encode location based information extracted from a media collection (the Flickr tagging system) into a single 2D physical label. This information is clustered by using locations metadata (geotags) and key-words (tags) associated to pictures. Our system helps two types of users: the user authoring the physical label and the final user who retrieves up-to-date information scanning the label with his/her camera phone. Preliminary results for a given seed word (the tag Napoli) on 3000 photographs are presented, together with some ad-hoc weighting factors that help in finding significant pictures (representing places) that can be associated to a specific area.\",\n \"Title: A visual tool for using design patterns as pattern languages\\nYear: 2010\\n\\nAbstract: Design patterns document successful solutions to recurrent problems in a specific software development domain. However, finding the patterns you need can be difficult, often requiring the designer to comprehend a long narrative description to understand the benefits, implications and trade-offs of each pattern and of its relationships with others. In this paper we propose a visual notation supported by a software tool that may help to identify patterns that could satisfy a designer's goals, as well as conveying the positive and negative relations among patterns, including dependencies and collisions among patterns selected for a specific problem. This work extends the concept of Softgoal Interdependency Graphs (SIG) enhancing them with a number of visual clues and interaction capabilities to help designers realize the contributions and trade-offs of their design ideas and the complexity of the solution space they are building up.\",\n \"Title: Evaluation of an Agent-Mediated Collaborative Production Protocol in an Instructional Design Scenario\\nYear: 2003\\n\\nAbstract: Distributed knowledge creation or production is a collaborative task that needs to be coordinated. A multiagent architecture\\n for collaborative knowledge production tasks is introduced, where knowledge-producing agents are arranged into knowledge domains\\n or marts, and a distributed interaction protocol is used to consolidate knowledge that is produced in a mart. Knowledge consolidated\\n in a given mart can be in turn negotiated in higher-level foreign marts. As an evaluation scenario, the proposed architecture\\n and protocol are applied to facilitate coordination during the creation of learning objects by a distributed group of instructional\\n designers.\",\n \"Title: Designing Le@Rning Objects With The Elo-Tool\\nYear: 2003\\n\\nAbstract: Technological innovations can be important factors for change. The Internet is one such and it has modified the way people live and interact. In education, the effect of this change is. visible in the way educational materials are designed, developed and distributed, and in the roles played by the teacher/designer, the student and the content provider. Learning Objects technology? and supporting tools now permits the generation of on-line educational materials. This paper presents a framework for the generation, integration and reuse of Learning Objects, intended to (a) resolve the limitations of existing tools (b) provide interoperability between Learning Objects, and (c) provide mechanisms to compose new learning objects from old.\",\n \"Title: Modelling Computer Game Based Educational Experience for Teaching Children about Emergencies\\nYear: 2010\\n\\nAbstract: The aim of this work is to support educators in the design process of computer game based learning experiences for teaching children about the risks of emergency. As an educational experience can be tailored to different student needs, the risk characteristics of emergency at hand, and the educational purpose of the experience, the proposed model includes the necessary elements to provide all this information. In this way the teacher can specify the requirements of the educational experience, and based on this information to propose possible configurations of the elements of the game.\",\n \"Title: MD2 method: the didactic materials creation from a model based perspective\\nYear: 2006\\n\\nAbstract: The creation of didactic materials is a complex task that needs an effective support for all practitioners involved in such process. This is the goal of the MD2 method presented in this paper. We propose the MD2 model to describe didactic materials requirements like its contents, pedagogical, technical and quality features. The rationale is to use some of those descriptors to provide mapping from high level technical descriptions of learning technology standards to simpler and closer descriptions to practitioners about material requirements. Those model mappings are used as foundation of MD2 creation method, and we show how they can guide the selection and composition phases of creation. By other side, another set of MD2 descriptors are used in the evaluation phase to control the usability and quality of the obtained material. A log of the whole process including the values of all model elements and the material's design rationales will be stored as extended semantic annotation. Thus, important properties of the created material like its interoperability, accessibility and reusability will be ensured.\",\n \"Title: Foreseeing the Transformative Role of IT in Lectures\\nYear: 2011\\n\\nAbstract: One of the most widely used methods for teaching is the lecture. During the last few decades lecturers and students have taken advantage of the progressive introduction of new technology for supporting these lectures. As this trend is very likely to continue, in this paper we will try to foresee some possible technology enriched future lecture scenarios.\",\n \"Title: Erratum Corrections to 'Modeling the Dynamic Behavior of Hypermedia Applications'\\nYear: 2001\\n\\nAbstract: First Page of the Article\",\n \"Title: Supporting Efficient Multinational Disaster Response through a Web-Based System\\nYear: 2002\\n\\nAbstract: The current process to deal with disaster mitigation has a number of drawbacks that can be solved using web technology. The basic problem is that there is a unidirectional and asynchronous flow of information among the different agents involved in a disaster mitigation procedure. This situation often results in a lack of coordination in the resources provision and in a useless assistance. In this paper we introduce ARCE, a web based system envisaged to cope with the lack of synchronism among assistance requests and responses in a multinational environment as the Latin-American Association of Governmental Organisms of Civil Defence and Protection is. ARCE makes uses of role-based access policies (RBAC) and information flow mechanisms to offer an efficient and reliable communication channel.\",\n \"Title: A Framework for the Multi-disciplinary Design of Web-Based Educational Systems\\nYear: 2009\\n\\nAbstract: The communication and the collaboration in a multi-disciplinary team can be diminished due to the different specification tools and languages used by the diverse members of the team. The MODUWEBapproach tackles this problem allowing the integration of different design perspectives through Model-DrivenDevelopment (MDD) techniques. Such integration is completely transparent to the users of the modeling languages, that is, the designers of the web-based educational systems, and in this way their productivity is not affected. This paper describes a prototype of a system which implements the MODUWEB approach to combine two domain specific languages dealing with different perspectives of the design of a Web-based educational system: IMS Learning Design for educational design and Labyrinth for web design.\",\n \"Title: Extending Relational Data Access Programming Libraries for Fuzziness: The fJDBC Framework\\nYear: 2002\\n\\nAbstract: Fuzzy relational databases have been extensively studied in recent years, resulting in several models and representation techniques, some of which have been implemented as software layers on top of diverse existing database systems. Fuzzy extensions to query languages and end-user query interfaces have also been developed, but the design of programming interfaces has not been properly addressed yet. In this paper, we describe a software framework called fJDBC that extends the Java Database Connectivity API by enabling fuzzy queries on existing relational databases, using externally-stored metadata. Since the main design objective of this extension is usability for existing database programmers, only a restricted subset of extensions (supported also by an extended object modelling notation) has been included. The overall design of the framework and some empirical results are also described.\",\n \"Title: Bridging the communication gap: a user task vocabulary for multidisciplinary web development team\\nYear: 2012\\n\\nAbstract: The design of Web-based systems is specially characterized by the multidisciplinary nature of Web Development Teams (WDTs). Due to this multidisciplinary, WDT members use different terminology that can lead to misunderstanding along the development process and, consequently, affect the resulting design. This problem has been identified during the physical design of websites, characterized by the sharing of ideas and the need of reaching a common understanding of the problem. With the purpose of avoiding misunderstanding among WDT members during this phase, it is proposed a controlled vocabulary of web user task. The definition of the vocabulary is based on the analysis of interaction design patterns. The paper describes the definition process followed for the construction of the user task vocabulary as well as the vocabulary itself. The final version of the controlled vocabulary compiles a total of thirty-four web user tasks and forty-one semantic relationships represented as synonyms. The vocabulary has been assessed through a heuristic evaluation, proving its correctness and completeness.\",\n \"Title: The collaborative development of didactic materials.\\nYear: 2005\\n\\nAbstract: In this paper we present an analysis of the development process of technology-supported didactic material. Such analysis considers didactic materials as the conjunction of contents and in- structional design used to guide learning and teaching processes. And we examine why several features such as reusability, semantic interoperability and collaboration support must be ensured from the earlier stages of the material creation process. For those reasons di- dactic material development is not a trivial task and demands of a development methodology support and a high-quality authoring en- vironment. We describe how the MD2 research project provides an integrated solution for creation of didactic materials that take into account those rationales. The MD2 solution is based on two ap- proaches: first, the definition of a method for the collaborative crea- tion of didactic materials and second, the elaboration of a quality evaluation framework for a priori testing of educational products. We also present CASLO a collaborative authoring tool used to facilitate these endeavors.\",\n \"Title: A Design Toolkit For Hypermedia Applications Based On Ariadne Development Method\\nYear: 2004\\n\\nAbstract: The development process of hypermedia applications implies very specific problems mainly related, first, to the use of navigational structures, interactive behaviours and multimedia compositions, and second, to the fact that are used by users with different levels of knowledge and skills, and also different security levels. This paper presents a design environment, AriadneTool, that allows a designer to model a hypermedia application, to validate such a design and to generate dynamically XML + SMIL implementation templates. This environment is based upon the Ariadne method which offers a set of integrated activities to model hypermedia applications in a systematic and iterative way. A practical example is shown to illustrate the use of the tool in the development of a hypermedia application.\",\n \"Title: Understanding citizen participation in crisis and disasters: the point of view of governmental agencies\\nYear: 2014\\n\\nAbstract: Ubiquitous computing combined with web 2.0 technologies might contribute to develop a culture of participation in emergency management (EM) by aligning the efforts and capabilities of official agencies and citizens. For citizen participation to be possible organizations in charge of EM need to realize that involving citizens does not interfere with their protocols and citizens need to be empowered to move beyond the role of passive informants. In this paper we describe how organizations perceive this participation as a step further to understand how to reach a more participative model and the benefits that technology and sociotechnical systems might bring to such model.\",\n \"Title: Standardizing the narrative of use cases: A controlled vocabulary of web user tasks.\\nYear: 2013\\n\\nAbstract: Context: For user interfaces design, the use of appropriate terminology in writing use case narratives may determine the effectiveness of the design process, facilitating communication within multidisciplinary web development teams and leading to agreed designs.Objective: This paper proposes a user task vocabulary for web user interface design. This vocabulary compiles terms related to the use of web applications, regardless of the application domain, as a way of standardizing the terminology used in the elaboration of use case narrative. The use of the vocabulary would help to reduce misunderstandings within multidisciplinary web development teams.Method: The construction of the vocabulary is based on the combination of both committee and empirical approaches. Committee approaches rely on experts in designing web applications, while empirical ones are focused on analyzing content objects, such as interaction design patterns and use case narratives.Results: The final version of the monolingual controlled vocabulary of web user tasks compiles a total of 40 tasks; each of them has a key term and a definition of the interaction carried out by users. Additionally, 41 semantic relationships were collected and represented as synonyms. The vocabulary has been assessed through an expert evaluation, proving its correctness and completeness, and an usability evaluation checking the efficacy of the vocabulary.Conclusion: The language employed in use case narratives can determine the value of use cases for designing user interfaces. The usage of a controlled vocabulary may allow designers to elaborate unambiguous use case narratives as a way of creating consistent task models for designing web user interfaces. (c) 2013 Elsevier B.V. All rights reserved.\",\n \"Title: Modelling Security Policies in Hypermedia and Web-Based Applications\\nYear: 2001\\n\\nAbstract: As hyperdocuments grow and offer more and more contents and services, some of them become more sensitive and should only be accessed by very specific users. Moreover, hypermedia applications can offer different views and manipulation abilities to different users, depending on the role they play in a particular context. Such security requirements have to be integrated into the development process in such a way that what is understood by a proper and safe manipulation of a hyperdocument has to be analysed, specified and implemented using the appropriate abstractions. In this paper we present a high-level security model applied to the modelling of security policies using components and services belonging to the hypermedia domain. The model uses negative ACLs and context-dependent user permissions for the specification of security rules. An example of its use for the design and operation of a web-based magazine is also described.\",\n \"Title: The Evaluation within the Development and Deployment of IMS LD-Based Didactic Materials: The MD2 + Runtime Adaptation Approach\\nYear: 2008\\n\\nAbstract: Evaluation is one of the most important activities in the didactic materials creation since it allows developers to check if the features of created material satisfy all the requirements established at begin of its development and if that material can be an effective support to achieve the educational goals of a particular instructional situation. Its results provide relevant information for the material redesign in such cases when those requirements or educational goals are not satisfied. In this paper we describe an approach to evaluate IMS LD-based materials during their development and deployment in an educational process.\",\n \"Title: WAY: An Architecture for User Adapted Access to Z39.50 Servers Based on Intelligent Agents\\nYear: 1998\\n\\nAbstract: The work presented in this poster is based on the combination of three well-known paradigms of Computer Science applied to\\n Digital Libraries: User Adaptive Interfaces, Information Retrieval and Intelligent Agents. Its objective is to define a model\\n providing intelligent information access by means of an adaptive user interface. The model, called WAY (see figure 1), is\\n supported by a web-based architecture and counts on the help of intelligent agents in charge of studying the user characteristics\\n in terms of previous behaviours, in order to provide an adapted interface and to guide the user’s searching process through\\n the servers available in the net. This model is currently being implemented in java using RMI (Remote Method Invocation) technology.\\n \\n Concerning user adaptive interfaces, what our model proposes is to offer a different initial interface for each type of user.\\n These initial interfaces will be defined according to the users classification, taking into account where the user is accessing\\n the system from. Once the user begins to interact with a specific interface, it will go on changing depending on the actions\\n performed by the user in two ways: the preferences shown explicitly by the user -selected options in the configuration of\\n the interface- and the preferences shown implicitly -by systematic actions. The following examples illustrate these ideas:\\n \\n \\n \\n \\n – \\n The type of user: in a university library environment, the possible types could be students, teachers and library staff, all\\n of them with quite different goals and needs.\\n \\n \\n \\n – \\n The user mother tongue: if the user is connecting from Germany, he/she is likely to prefer a German interface.\\n \\n \\n – \\n The user preferences: there are people who still prefer textual environments although their computers allow a good performance\\n of visual ones.\\n \\n \\n \\n – \\n The user repeated actions: in a university, students usually are more interested in books than in journals, unlike teachers,\\n whose main research tools are papers.\",\n \"Title: LPCEL Editor: A Web-Based Visual Authoring Tool for Learning Design\\nYear: 2012\\n\\nAbstract: Educational Modeling Languages (EMLs) provide the framework to represent learning processes in a formal fashion. The IMS-LD is a widely used EML and there have been created several tools to facilitate the authoring process of a course for that specification. However, since most of these tools are meant to be IMS-LD complaint they are also restricted by its level of expressiveness. To solve this issue, the LPCEL Editor is presented to facilitate the authoring of a course by means of a visual tool while maintaining a broad level of expressiveness.\",\n \"Title: Designing Educational Games by Combining Other Game Designs\\nYear: 2012\\n\\nAbstract: The complexity and sophistication of computer games is growing every day, not only in terms of graphical resources and advanced interaction mechanisms but also with regards to their narratives and their rules. In this paper we propose to tackle the complexity related to the rules and narratives of a game design by describing it through combinations of more simple game designs. This approach not only facilitates the description of game designs that are easy to manage and understand but also enables the reuse of game design components, and also allows the designer to respond to established trends in computer games such as the use of \\\"missions\\\" and \\\"mini-games\\\". The proposed approach has been applied to the design and implementation of an educational game (EG) called \\\"Safety Village\\\" of the minigame genre, which aims to help raise children's awareness of emergencies and domestic risks.\",\n \"Title: Designing usable educational material for English courses supported by mobile devices\\nYear: 2010\\n\\nAbstract: Mobile Learning (M-Learning) may offer many advantages when designing educational processes as it can help to overcome restrictions of time and place. However, it is necessary to consider the special features of the type of devices used to follow these type of courses in order to guarantee the usability of the learning objects produced for this eLearning modality. In this document we describe the process of designing a set of courses which aim to support learners when developing English grammar, reading and listening skills, explaining the guidelines we have followed to ensure the usability of the final product.\",\n \"Title: Web Design Patterns: Investigating User Goals and Browsing Strategies\\nYear: 2009\\n\\nAbstract: Design patterns document in a systematic way design solutions to recurrent problems and they are expressed using non-technical terms, so that a wider audience can understand them. Thus they could be useful tools to improve communication in interdisciplinary teams and to integrate end-users in participatory design processes. However, the difficulties of using patterns go beyond the lexicon used in the patterns description. The individuals who might use the patterns may be following different strategies when browsing a collection of patterns, strategies that are determined by their goal at a specific point during the development process. Moreover, the strategy they follow can have some influence in the quality of the proposed solution. In this paper we describe an empirical study that has been performed to answer some of these questions. In the study we gathered information on browsing strategies and user goals when using a patterns catalogue to design a web system. We also analyzed the relation among the goal and the strategy as well as their impact in the quality of the use of the patterns. This investigation is part of a larger project intended to design patterns catalogues that take into account the goals and expectations of their end-users, who are not necessarily experts either on web design or on design patterns.\",\n \"Title: Modelling hypermedia and web applications: the Ariadne development method\\nYear: 2005\\n\\nAbstract: The development process of hypermedia and web systems poses very specific problems that do not appear in other software applications, such as the need for mechanisms to model sophisticated navigational structures, interactive behaviors, interfaces with external applications, security constraints and multimedia compositions. Even though experience, modelling skills and abstractions can be borrowed from existing software design methods, such as object-oriented modelling, hypermedia developers need specific mechanisms to analyze and design using entities that belong to the hypermedia domain (such as nodes, links, anchors and space and time-based relationships). Moreover, hypermedia methods should provide mechanisms to deal with all the aforementioned features in a progressive and integrated way. In this paper, we present the Ariadne Development Method (ADM), a software engineering method that proposes a systematic, flexible, integrative and platform-independent process to specify and evaluate hypermedia and web applications. ADM has been shown particularly useful in complex systems involving a huge number of users with different abilities to access information, with a complex structure where a huge number of nodes have to be organized in a clear way to produce specifications that are discussed by people with an heterogeneous background. This is the case of ARCE, a Latin American project where 21 countries are cooperating to produce a web platform to improve assistance in disaster mitigation situations.\",\n \"Title: The Automatic Generation of Semantic Annotations for Didactic Materials and the Use of Models in the Material Development to Improve its Reusability\\nYear: 2008\\n\\nAbstract: Through the past two decades, education in computer and information science and technology (CISE) has moved toward a model that pervasively incorporates programming projects and other engaging student activity. Realistic activities and materials are ...\",\n \"Title: Instructional Software Analysis: Lessons From Software Development Process Improvement\\nYear: 2007\\n\\nAbstract: Instructional software can be defined as any computer program used for instruction. As a means to optimise the development process of instructional software, different authors have defined a range of methods based on Software Engineering. However, the use of a method does not guarantee the validity and quality of the product developed; hence, a series of Software Process Improvement (SPI) approaches aimed to improve and guarantee the development process that have arisen.The purpose of this paper is to review the aforementioned approaches and to apply them to the analysis phase of the instructional software development process. The analysis phase aims to define the conditions and needs of the project in order to solve uncertainties in early stages of the process.\",\n \"Title: Formalization of web design patterns using ontologies\\nYear: 2003\\n\\nAbstract: Design patterns have been enthusiastically embraced in the software engineering community as well as in the web community since they capture knowledge about how and when to apply a specific solution to a recurring problem in software systems. However, web design involves both cognitive and aesthetic aspects, for that there are several design patterns that describe the same problem but from different points of view and with different vocabulary, so it is more difficult to understand and to reuse that knowledge. To achieve a common vocabulary and improve reusability we propose to formalize web design patterns by means of ontologies. At the same time the ontology would allow us to express web design patterns in a formal way, that can be understood by a computer. So a design pattern knowledge base can be integrated in a software tool for web application modeling in order to suggest web design patterns that better suit some design requirements. Moreover, changes and alterations needed for applying design patterns to the design can be proposed. This paper describe the core ontology using DAML+OIL and show how web design patterns can be described by our ontology.\",\n \"Title: Instructional Domain Analysis: A Methodological Approach to Service-Oriented Learning\\nYear: 2008\\n\\nAbstract: The development of a learning system based on integrating a number of learning services needs both a technological platform to support the system as well as a methodology that manages the development process. Such technological platform is provided by the service oriented learning architecture (SOLA) that defines an architecture style guiding several aspects of deploying units of learning that are packaged as services. The purpose of this paper is to review the SOLA concept and present a specific methodology, based on analysing instructional domains, to complement the SOLA approach. The method here proposed addresses the identification and classification of learning services to facilitate the integration of such services.\",\n \"Title: A modular approach to support the multidisciplinary design of educational game experiences\\nYear: 2012\\n\\nAbstract: The design of a computer game based educational experience is a multidisciplinary task that requires the collaboration of experts in game design, education and in the field of instruction. In this paper we present an educational game (EG) design method which tackles this multiplicity of backgrounds allowing each of the experts to focus on the aspects of the game design related to his/her area of expertise. The method is supported by a modular conceptual model that provides a common framework for describing an EG and facilitates the reuse of design components and the description of new game variants. In order to illustrate the proposal we describe the process of design and implementation of 'Maz-E-nglish', an EG for mobile devices which aims to help children learning English grammar.\",\n \"Title: From requirements to implementations: a model-driven approach for web development\\nYear: 2007\\n\\nAbstract: Model-Driven Development (MDD) is an appropriate paradigm for web development since interoperability and flexibility are required to cope with implementation technologies and functionalities that are in permanent evolution. In this paper, we describe and illustrate the MDD process of the ADM (Ariadne Development Method) hypermedia/web engineering method. The two cornerstones of the ADM are the Labyrinth++ meta-meta-model, which formalizes the core constructs used within all the design meta-models, and the meta-meta-model specification as an ontology that provides semantics and reasoning not only for model transformations but also for consistency checking and model validation. These features have been essential in the development of a CASE tool, called AriadneTool that supports the different abstract levels of modeling, model transformations as well as the generation of light prototypes in different web implementation technologies.\",\n \"Title: Interactive Accessible Notifications for Emergency Notification Systems\\nYear: 2009\\n\\nAbstract: Notifications are critical when an emergency scenario is going to happen (e.g. a hurricane approaching); so the ability to transmit notifications to different kind of users is a crucial feature for Emergency Management Systems. In this work an ontology was developed by investigating different sources: accessibility guidelines, emergency response systems, communication devices and technologies, taking into account the different abilities of people to react to different alarms (e.g. mobile phone vibration as an alarm for deaf blind people). The knowledge codified in the proposed ontology could be used to enhance and promote the use of non-conventional interfaces for notifying emergency messages thus providing accessibility under different conditions and for different kind of users.\",\n \"Title: Visual representation of web design patterns for end-users\\nYear: 2008\\n\\nAbstract: In this paper, we discuss the use of visual representations of web design patterns to help end-users and casual developers to identify the patterns they can apply in a specific project. The main goal is to promote design knowledge reuse by facilitating the identification of the right patterns, taking into account that these users have little or no knowledge about web design, and certainly not about design patterns, and that each pattern might include some trade-offs users should consider to make more rational decisions.\",\n \"Title: Assessing the utility of an interactive electronic book for learning the Pascal programming language\\nYear: 2000\\n\\nAbstract: Hypermedia is a broadly accepted technique to develop educational systems since its hypertext structure reflects a model of learning based on the students' semantic memory model and the use of multimedia provides interactive mechanisms that allow managing, manipulating and organizing the lessons. A hypermedia electronic book called CIPP (Curse Interactive de Programacion en Pascal) is introduced to help students learn the Pascal programming language and the empirical evaluation that was carried out to assess the book utility as an educational tool. One of the most encouraging results from this experience was that, at the end of the course, not only did most students agree with the didactic method which integrated lectures with the use of the electronic book, but also they felt motivated to continue learning Pascal by themselves.\",\n \"Title: CARLOS: A Collaborative Authoring Tool for Reusable Learning Objects\\nYear: 2003\\n\\nAbstract: The development of learning contents is a collaborativeprocess in which, users with different backgrounds, experiencesand points of view can take part. This is a two-stepprocess: first, a negotiation and evaluation of ideasamongst participants and second, composition of learningcontents as result of that negotiation. However the collaborativedevelopment support in current learning contentsauthoring tools is scarce, since they usually providea uni-personal vision of the creation process. This workpresents a multi-agent system for the collaborative authoringof Reusable Learning Objects (RLO), which key featuresare: (1) collaboration stakeholders are representedby agents; (2) agents message exchange is coordinated bymeans of a negotiation protocol; (3) agents rationality forproposal evaluation is modelled in terms of preference relationships;(4) a group of assistant agents trace all negotiationevents, so allowing the whole creation process to beaudited, whilst keeping a repository to control changes accomplishedinto the RLO corpus, thus allowing automatedconsolidation of negotiated results.\",\n \"Title: Learning Web Services Composition and Learner Communities Support for the Deployment of Complex Learning Processes\\nYear: 2004\\n\\nAbstract: Educational models are subject to a constant evolution and permanent technological developments, with new visions and learning models emerging to face them. These usually include diverse didactic strategies into the learning process. Learning Management Systems currently evolve towards distributed learning object systems with decentralized execution and integration with heterogeneous applications. The notion of a centralized repository of learning objects should change onto distributed communities of learning objects producers and consumers. In this paper, we present a learning web services framework to support the integration of newer, complex learning processes and the dynamic generation of content-based communities of interest. Nowadays, educational models are immersed in a constant knowledge evolution and permanent technological development, new challenges arise from that globalized environment, thus, a new vision and learning models should emerge in order to face them. These new models must include diverse didactic techniques strategies in the learning process. We also believe that actual Learning Management Systems (LMS) should evolve towards integrating systems of distributed learning objects with decentralized execution and integration with heterogeneous applications; the notion of a centralized repository of learning objects should change onto distributed communities of learning objects producers and consumers. In this paper, we present a learning web services framework to support the integration of newer, complex learning processes and the dynamic generation of content-based communities of interets.\",\n \"Title: Collaborative hypermedia systems: A model of architecture\\nYear: 1997\\n\\nAbstract: CO-OPERATIVE AUTHORING IN HYPERMEDIA SYSTEMS have recently gained importance to such an extent that the next generation of\\n hypermedia systems should be defined with the acronym IOCH: Integrated Open and Collaborative Hypermedia. An architecture\\n model supplies a set of modules and interfaces that allow systems facilities and components to be specified. This paper presents\\n a model of architecture for IOCH systems that tackles problems associated with this kind of environment, such as system openness\\n and distribution, information security and collaborators’ communication. This model has been developed taking into account\\n three basic principles: modularity, abstraction, and IOCH support.\",\n \"Title: Requirements for Hypermedia Development Methods: A Survey of Outstanding Methods\\nYear: 2002\\n\\nAbstract: The aim of this paper is to present a framework of requirements to survey design methods for hypermedia systems. Such requirements are taken from software engineering as well as from hypermedia engineering fields. Finally, these requirements are applied to a set of outstanding design methods in order to identify both their good qualities and their lacks.\",\n \"Title: A model-driven approach for the visual specification of Role-Based Access Control policies in web systems\\nYear: 2008\\n\\nAbstract: Specifying the access policy of a web system is a relevant design concern that is often dismissed or postponed until the implementation. ADM-RBAC (Ariadne Development Method with Role-Based Access Control) is a model-driven approach for web systems that supports the specification of access control policies in an integrated way and at two abstraction levels. At the conceptual level a number of visual models specify the access policy in a way that is similar to the users’ point of view. At the detailed level, models are oriented towards providing enough details to generate prototypes in an automatic or semiautomatic way. In this paper we describe the visual models of ADM-RBAC and their empirical evaluation.\",\n \"Title: Using recommendations to help novices to reuse design knowledge\\nYear: 2011\\n\\nAbstract: The use of pattern languages is not so straightforward since itsusers have to identify the patterns they need, browsing the language and understanding both the benefits and trade-offs of each pattern as well as the relations and interactions it has with other patterns. Novice designers might benefit from tools that assist them in this learning task. In this paper we describe a recommendation tool embedded in a visual environment for pattern-based design which aims at suggesting patterns to help novice designers to produce better designs and understand the language.\",\n \"Title: ELO-Tool: Taking Action in the Challenge of Assembling Learning Objects\\nYear: 2008\\n\\nAbstract: Nowadays, a wide range of initiatives are focused on providing solutions relating to the integration and reuse of different types of learning objects. This paper deals with the assembly of learning objects, one of the most difficult components for reuse. Our proposal takes into account the requirements and competencies defined for each learning object in order to allow them to be assembled in a coherent way. As a result of this approach, we have developed ELO-Tool, a web application that implements an assembly mechanism based on a semantic comparison of requirements and competencies through the use of ontologies. Moreover, the application generates the appropriate set of meta-data to describe the new learning objects resulting from the assembly process.\",\n \"Title: A Mixed Interaction Platform For Supporting Large-Scale Crisis Storytelling\\nYear: 2013\\n\\nAbstract: Crowdsourcing is a distributed approach in which people participate and share information over the Web (e.g. Facebook or Twitter). This distributed model has proved to be helpful in accelerating the perception of what occurred, where it happened, and who needed help in recent disasters such as the Boston Marathon bombs, the Oklahoma tornado or the Central Europe floods. Nevertheless, this kind of sources might provide unreliable, partial, ambiguous and inconsistent information that do not necessarily help to understand the situation. An alternative may be the combination of crowdsourcing activities and more official flows of information to make up a coherent big picture that support the needs of decision makers. This paper introduces a software approach conceived to convey stories created from different sources -official and unofficial-as a way of depicting situations in a collaborative manner.\",\n \"Title: A Collaborative Authoring of Learning Scenarios Using the LPCEL Editor\\nYear: 2013\\n\\nAbstract: Learning scenarios are formally represented through Educational Modeling Languages (EMLs). The IMS-LD is a commonly used EML and several compliant visual editors are being created for the authoring of learning scenarios. However, these editors have a limited level of expressiveness. The LPCEL Editor facilitates the authoring process with a visual tool that includes the mechanisms for a collaborative authoring process while providing a broad level of expressiveness.\",\n \"Title: A Web Service for Hypermedia Role-Based Policies\\nYear: 2005\\n\\nAbstract: High level security is a key requirement in hyperme- dia/web applications. The systems opening to the Internet makes the research effort to move towards protecting the information transmission (i.e. SOAP messages, policy de- scriptions. . . ), but little attention is paid to what the user can do with the system. Role-based access control (RBAC) allows to formulate the organization's resource access pol- icy in a natural way, so a role-based access model for hy- permedia will make it easier to integrate the security design with the rest of the system design. In service oriented archi- tectures, an access policy service would allow to gather the management and deployment of the security policy in dis- tributed and heterogeneous environments. This paper de- scribes a role-based access control model for hypermedia called MARAH, and its implementation as a web service. An use case of the model in the design of the ARCE appli- cation is also discussed.\",\n \"Title: Sharing your view: A distributed user interface approach for reviewing emergency plans\\nYear: 2014\\n\\nAbstract: Emergency planning is an ongoing activity in which a multidisciplinary group of experts intermittently collaborate to define the most appropriate response to risks. One of the most important tasks of emergency planning is the review of plans as a way of maintaining, refining, and improving them. This review of plans is based on exchanging knowledge and experiences in order to take into account different perspectives and generate alternative solutions. An exploratory case study carried out within municipal organizations has disclosed how the application of rigid plan reviewing practices hinders team creativity and, consequently, effective decision-making. This paper presents a computer-based collaborative environment aimed at supporting unstructured team discussion during the post-hoc review of emergency plan. This collaborative environment allows emergency planning team members to share their view in a free manner by interacting with user interface components distributed across several input and output dimensions. The usage of the environment has proved how the application of new interactive technologies can create more dynamic work settings, fostering team creativity.\",\n \"Title: Spreading design patterns with semantic web technologies\\nYear: 2006\\n\\nAbstract: There are a huge number of design patterns that can be used in specific software domains, not only in object-oriented software design. Several of these collections are disseminated as structured but informal documents, at best supported with hypertext tools on the web. These passive representations compromise usability of design patterns. We proposed to enrich the textual pattern description with semantic annotations that enable a machine and a human understanding, like in the Semantic Web. In this paper, we present an annotation tool to support the development of semantic pattern repositories. Moreover, in order to show the utility of this approach two software tools with different purposes have been developed: a semantic web repository to explore patterns and a pattern wizard to apply patterns into a design toolkit.\",\n \"Title: A hypermedia course in Spanish informatics engineering\\nYear: 1997\\n\\nAbstract: Public and private companies are continuously asking to the Professional Orientation Service of the University Carlos III de Madrid for technical engineers in informatics trained in areas related to hypermedia technology. For this reason, the Department of Computer Science of UC3M decided to create a new course, called \\\"Hypermedia Systems: Design and Evaluation,\\\" with a view to covering this subject applying basic principles of software engineering and HCI. This paper describes the structure and contents of this new course oriented towards introducing students in hypermedia systems and also presents our experience as the teachers of such course.\",\n \"Title: An Ontology-Based Mechanism for Assembling Learning Objects\\nYear: 2005\\n\\nAbstract: This paper presents OntoGlue, an ontology-based mechanism for assembling learning objects. This mechanism introduces the concept of associated knowledge, which represents the set of requirements that a learning object needs in order to be used and a set of competencies that the learning object provides after its comprehension. According OntoGlue, in order to assemble two learning objects, the requirements of one learning object must be covered by the competencies of the other. In addition, to facilitate interoperability between different domains (vocabularies), the concepts that conforms the associated knowledge are selected among the classes of educational ontologies.\",\n \"Title: A methodological approach for hypermedia security modeling\\nYear: 2003\\n\\nAbstract: In hypermedia systems security is becoming a key requirement to preserve both confidentiality and integrity. Although some authorization models for hypermedia have been proposed, what is needed is to integrate security modeling into the whole development process, so that designers count on methods to specify all the features of their hypermedia systems, including navigation capabilities, interactivity, multimedia features as well as security. In this paper, we describe how security modeling is approached in a methodology for hypermedia systems, called Ariadne, that offers a number of conceptual and platform-independent tools to specify the features of any hyperdocument in an integrated and progressive way.\",\n \"Title: Augmented Presentations: Supporting The Communication In Presentations By Means Of Augmented Reality\\nYear: 2014\\n\\nAbstract: This work aims to explore the benefits and potential uses of Augmented Reality technology for supporting communication in presentations. This article presents the architecture and implementation of an Augmented Presentation Feedback System. The system allows a speaker equipped with an Augmented Reality Head-Mounted Display to display visual cues depicted over the listeners' heads. These can be used as a way to provide the speaker with continuous, private, and immediate feedback on his or her explanations. The results of a case study conducted showed that the system not only assists the speaker in adapting the content and pace of the explanation to the listener but also helps to better manage their interventions and improve the flow of the presentation.\",\n \"Title: Citizen Participation and Social Technologies: Exploring the Perspective of Emergency Organizations.\\nYear: 2014\\n\\nAbstract: Current technological advances on ubiquitous computing and web 2.0 open up new possibilities to promote an active participation of citizens in different domains including emergency management. Such a kind of participative model requires not a proactive attitude from citizens but also of the implication of emergency management organizations that have the responsibility of managing the situation. Emergency management is a highly professional domain characterized by the stress that emergency workers experience when facing unpredictable events that have a social and economic impact in society. Citizens could contribute in this process as far as they do not interfere with the protocols and activities of professional workers who will not accept any change that could compromise their efficacy. Many research works focus on how citizens utilize social technologies during emergency situations for self-organizing or for citizen journalism, however, the perspective of emergency management organization has been less explored. In this paper, we present a study that goes deeper into how organizations envision the use of technologies to increase citizen participation in their procedures. This study aims at being a step further to understand how a more active and effective citizen role could be reached and how technologies could contribute to this end.\",\n \"Title: Exploring Interaction Possibilities in Educational Games: A Working Proposal\\nYear: 2014\\n\\nAbstract: The design of the user interfaces for educational games (EGs) poses specific challenges, as this feature does not only have an impact on the game playability but can also be used to reinforce learning or to establish associations between concepts. However, implementing advanced in-game interactions can be an issue due to the wide range of technologies for defining input modalities, actions and events that game designers need to consider. In this working paper, we propose an approach to ease the development of educational games that go one step beyond classical mouse and keyboard interaction and provide interaction alternatives within the same game rationale. Our proposal is based on the integration of a game design model and an ubicomp interaction toolkit that manages heterogeneous devices.\",\n \"Title: Human-Display Interaction Technology: Emerging Remote Interfaces for Pervasive Display Environments\\nYear: 2010\\n\\nAbstract: We're living in a world where information processing isn't confined to desktop computers-it's being integrated into everyday objects and activities. Pervasive computation is human centered: it permeates our physical world, helping us achieve goals and fulfill our needs with minimum effort by exploiting natural interaction styles. Remote interaction with screen displays requires a sensor-based, multimodal, touchless approach. For example, by processing user hand gestures, this paradigm removes constraints requiring physical contact and permits natural interaction with tangible digital information. Such touchless interaction can be multimodal, exploiting the visual, auditory, and olfactory senses.\",\n \"Title: Seeking Reusability of Computer Games Designs for Informal Learning\\nYear: 2011\\n\\nAbstract: In order to enjoy the benefits that the use of computer games may provide for supporting the area of informal education, it is necessary to rely on design models, methods and tools to help reduce the high costs traditionally associated with the development of these kinds of systems. In this paper we present a model which seeks to facilitate the reuse and adaptation of designs of these types of games. The model has supported the implementation of two different games for training children on emergency situations.\",\n \"Title: Personalized alert notifications and evacuation routes in indoor environments.\\nYear: 2012\\n\\nAbstract: The preparedness phase is crucial in the emergency management process for reaching an adequate level of readiness to react to potential threats and hazards. During this phase, emergency plans are developed to establish, among other procedures, evacuation and emergency escape routes. Information and Communication Technologies (ICT) can support and improve these procedures providing appropriate, updated and accessible information to all people in the affected zone. Current emergency management and evacuation systems do not adapt information to the context and the profile of each person, so messages received in the emergency might be useless. In this paper, we propose a set of criteria that ICT-based systems could achieve in order to avoid this problem adapting emergency alerts and evacuation routes to different situations and people. Moreover, in order to prove the applicability of such criteria, we define a mechanism that can be used as a complement of traditional evacuation systems to provide personalized alerts and evacuation routes to all kinds of people during emergency situations in working places. This mechanism is composed by three main components: CAP-ONES for notifying emergency alerts, NERES for defining emergency plans and generating personalized evacuation routes, and iNeres as the interface to receive and visualize these routes on smartphones. The usability and understandability of proposed interface has been assessed through a user study performed in a fire simulation in an indoor environment. This evaluation demonstrated that users considered iNeres easy to understand, to learn and to use, and they also found very innovative the idea to use smartphones as a support for escaping instead of static signals on walls and doors.\",\n \"Title: Software Support for Multitouch Interaction: The End-User Programming Perspective.\\nYear: 2016\\n\\nAbstract: The hardware development of the past years favored the widespread diffusion of multitouch devices (such as smartphones, tablets, and interactive tabletops) to such an extent that a wide variety of users are now exploiting them to perform different activities on a daily basis. In the heterogeneous and manifold context of modern computation, it is impossible to predict, at design time, all the possi...\",\n \"Title: Designing educational games through a conceptual model based on rules and scenarios\\nYear: 2015\\n\\nAbstract: The design of a successful educational game (EG) is a challenging task that requires a lot of knowledge and a variety of skills. EG designers not only have to deal with the inherent technical complexity of game design, but also have to be able to interweave learning activities in a way that is enjoyable and educationally effective at the same time. In order to make available the benefits of game based learning to a wider audience, it is necessary to provide means to alleviate the cost of envisioning new EG by providing tools that might contribute to make the design process easier and quicker. As a first step towards this goal, in this paper we introduce a conceptual model that organizes in a modular way and in different design perspectives the game features. In order to help EG designers, the features that are most often regarded in the literature as significant in producing engaging, fun and educational game experiences, have been included in the model through a set of design entities. Furthermore, the organization of the elements of the model facilitates reusing pieces of the EG designs to quickly produce variants of the same game which can be used to match different learning purposes. The opinions gathered from the educators and game designers that participated of an EG design workshop confirmed that the model can help multidisciplinary EG design teams. Moreover, the model successfully contributed to the process of designing a collection of EGs aimed at raising children ́s awareness of emergencies and domestic risks, whose educational and ludic value was assessed in an experience conducted with students and educators at a primary school in Madrid.\",\n \"Title: An Augmented Lecture Feedback System to Support Learner and Teacher Communication.\\nYear: 2013\\n\\nAbstract: In this paper, it is advocated that the feedback loop between learners and teachers could be improved by making use of augmented reality (AR) techniques. The bidirectional communication between teacher and learners is sometimes hampered by students' fear of showing themselves up in front of their classmates. In order to overcome this problem, a system is proposed whereby teachers receive immediate and private feedback both individualised for each student as well as aggregated for the whole class. With that purpose, the teacher, who is equipped with a head-mounted AR display, can visualise symbols that represent the status students have stated using private devices in relation to the lecture content. In order to explore the possibilities of this approach, an experience was conducted in a lecture on a university course. The results are encouraging and suggest that as this technology matures and less intrusive AR display models become available, it could provide effective support to improve communication and interaction during lectures. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qUCkNkuAiK8\",\n \"Title: Engineering the Creative Co-design of Augmented Digital Experiences with Cultural Heritage\\nYear: 2015\\n\\nAbstract: Ubiquitous and tangible computing is opening a new panorama for interactive applications in different domains including cultural heritage. To ideate augmented experiences that provide more enjoyable, intrinsically motivating and memorable user experiences, design thinking methods that fuel the imagination and creativity of designers are required. This design can also take profit from software engineering approaches aimed at putting rationality concepts in practice. In this paper we advocate that such complex interactive (eco) systems require a mixed approach where the benefits of both disciplines are taken into account. It is not a question of design thinking versus software engineering, but a challenge to face the process both as people-values-centered and as quality-centered. This was the motivation of the CoDICE (COdesigning DIgital Cultural Encounters) software tool that supports situated, collocated and distributed tasks and adds persistence and traceability to the co-design outcomes so that the design rationale behind the products can be made explicit.\",\n \"Title: A Platform for Creating Digital Educational Games as Combinations of Archetypical Games.\\nYear: 2015\\n\\nAbstract: In this work we present a platform that allows educators to design and develop 3D Digital Educational Games (DEG) rapidly and easily. The games are described as combinations of four simple game archetypes, which can be played sequentially or simultaneously along different missions and episodes. This seeks to provide educators, with no prior knowledge on game design, with a comprehensive approach for describing educational game experiences.\",\n \"Title: A See-Through Display for Interactive Museum Showcases\\nYear: 2015\\n\\nAbstract: We present a prototype of an interactive showcase for museum exhibits that exploits a multi-touch see-through display screen. The transparent display makes it possible to superimpose an overlay of digital information while observing the physical object behind the screen. We developed an application that allows visitors to tell their experience with the object as well as to introduce comments on other visitors contributions. Our goal is to engage users in the creation of digital narratives with cultural heritage artifacts, thus constructing new layers of meaning that are parallel to the official ones provided by curators. Results from a formative study give promising feedbacks on the usefulness, novelty and attractiveness of the prototype.\",\n \"Title: A Platform for Supporting the Development of Mixed Reality Environments for Educational Games\\nYear: 2015\\n\\nAbstract: In this work we present MR-GREP, a platform that supports educators in the design and implementation of mixed reality educational games. More specifically the system allows the instructional designers to create game experiences that can be played simultaneously in an augmented reality environment as well as in a virtual space that replicates the physical space. This seeks to support the implementation of collaborative learning experiences that combine the flexibility provided by the virtual worlds with the realism and physical component that training in real scenarios allows. The development of this type of environments usually demand advanced technical knowledge that educators normally lack. The platform aims to overcome this problem by providing a set of authoring tools and applications, which does not require programming skills from the user.\",\n \"Title: Inmersive End User Development for Virtual Reality.\\nYear: 2016\\n\\nAbstract: In this paper we present VR GREP, an immersive End User Development (EUD) tool that supports authoring and modifying general purpose immersive VR environments, without having technical knowledge. The system aims to facilitate exploring the potential of immersive tools to support situated design practices.\",\n \"Title: Augmenting Smart Objects for Cultural Heritage: A Usability Experiment.\\nYear: 2016\\n\\nAbstract: In recent years the explosive growth of smartphones and the evolution of mobile communication networks have certainly revolutionized the way how people communicate and access information. This growing adoption of technology creates also some challenges. It is struggling to teach people who has had an increased exposure to technology. Cultural heritage organizations deal with this issue endlessly and look to the new technologies as an opportunity to transform and enhance the exhibition experience for matching the interest of the newest visitors. In this paper we focus on the augmented reality (AR) technologies and the role that they play to connect visitors to the modern exhibitions. Moreover, we define for the first time the concept of Augmenting Smart Object (ASO) that arises from the study of the state of the art of the AR systems applied to the cultural context and from our direct experience in a participatory design aimed at developing and evaluating an AR system for a museum exhibition.\",\n \"Title: Designing Mobile Applications for Emergency Response: Citizens Acting as Human Sensors.\\nYear: 2016\\n\\nAbstract: When an emergency occurs, citizens can be a helpful support for the operation centers involved in the response activities. As witnesses to a crisis, they initially can share updated and detailed information about what is going on. Moreover, thanks to the current technological evolution people are able to quickly and easily gather rich information and transmit it through different communication channels. Indeed, modern mobile devices embed several sensors such as GPS receivers, Wi-Fi, accelerometers or cameras that can transform users into well-equipped human sensors. For these reasons, emergency organizations and small and medium enterprises have demonstrated a growing interest in developing smart applications for reporting any exceptional circumstances. In this paper, we present a practical study about this kind of applications for identifying both limitations and common features. Based on a study of relevant existent contributions in this area and our personal direct experience in developing and evaluating emergency management solutions, our aim is to propose several findings about how to design effective and efficient mobile emergency notification applications. For this purpose we have exploited the basic sensors of modern mobile devices and the users' aptitude for using them. The evaluation consists of a practical and a theoretical part. In the practical part, we have simulated a traffic accident as closely as possible to a real scenario, with a victim lying on the ground near a car in the middle of a street. For the theoretical part, we have interviewed some emergency experts for collecting their opinions about the utility of the proposed solution. Results from this evaluation phase confirm the positive impact that EN application have for both operators' and citizens' perspective. Moreover, we collected several findings useful for future design challenges in the same area, as shown in the final redesign of the proposed application.\",\n \"Title: Coproduction as an Approach to Technology-Mediated Citizen Participation in Emergency Management.\\nYear: 2016\\n\\nAbstract: Social and mobile computing open up new possibilities for integrating citizens' information, knowledge, and social capital in emergency management (EM). This participation can improve the capacity of local agencies to respond to unexpected events by involving citizens not only as first line informants, but also as first responders. This participation could contribute to build resilient communities aware of the risks they are threatened by and able to mobilize their social capital to cope with them and, in turn, decrease the impact of threats and hazards. However for this participation to be possible organizations in charge of EM need to realize that involving citizens does not interfere with their protocols and that citizens are a valuable asset that can contribute to the EM process with specific skills and capabilities. In this paper we discuss the design challenges of using social and mobile computing to move to a more participatory EM process that starts by empowering both citizens and organizations in a coproduction service envisioned as a partnership effort. As an example, we describe a case study of a participatory design approach that involved professional EM workers and decision makers in an effort to understand the challenges of using technology-based solutions to integrate citizen skills and capabilities in their operation protocols. The case study made it possible to identify specific roles that citizens might play in a crisis or disaster and to envision scenarios were technologies could be used to integrate their skills into the EM process. In this way the paper contributes to the roles and the scenarios of theory-building about coproduction in EM services.\",\n \"Title: Emergency Management and Smart Cities: Civic Engagement Through Gamification.\\nYear: 2016\\n\\nAbstract: Nowadays, an increasing amount of cities tend to improve their community life applying smart city principles. The basic idea is to connect citizens to each other, to services, infrastructures and political and non-political organizations to take advantage of a continuous collective collaboration. In this context, the Emergency Management (EM) process becomes a critical aspect. It can exploit the citizens and organizations collaboration to reduce the risks of emergencies and the response time, to act more efficiently and with a better awareness. In this paper, we describe the redesign of an Emergency Notification (EN) application that is part of a set of applications aimed at providing citizens and organizations with easy and immediate means to cooperate. The redesign is based on Gamification and the Self-Determination Theory (SDT) principles in order to improve the user experience and foster the civic participation. The new gamified design was evaluated through an exploratory focus group involving common citizens and practitioners.\",\n \"Title: Integrating user stories to inspire the co-design of digital futures for cultural heritage.\\nYear: 2016\\n\\nAbstract: Co-design as a tactic of exploring and shaping possible futures would benefit from contributions of unwitting participants. That is, researchers gather information from them while performing some activities without participants being explicitly aware of it. We propose a platform that supports co-designers in capturing unwitting user-generated contributions and use them in the co-design of meaningful user experience for digitally augmented cultural heritage exhibitions. We report on a use case for ideating futures for cultural heritage and discuss the tradeoffs of involving unwitting participants in exploratory design as well as lessons learnt on the integration of users contributions into co-design processes.\",\n \"Title: Creating Interactive and Realistic Augmented Reality Experiences.\\nYear: 2016\\n\\nAbstract: Despite the recent advances in augmented reality (AR) technology most AR applications still fail to provide a seamless integration of the virtual objects in the augmented environment. To help alleviating this situation in this paper we propose an approach for supporting the implementation of interactive and realistic AR experiences, in which virtual objects can be occluded and collide with real ones and, in general, appear as merged into the real setting. The approach combines the use of model-based AR techniques with the advantages of current game engines, and it has been implemented using an existing game platform named GREP. We also present an experience carried out to assess the feasibility of the approach, in which more than 100 people played two AR games implemented following the proposed technique.\",\n \"Title: Using combinatorial creativity to support end-user design of digital games.\\nYear: 2017\\n\\nAbstract: To really exploit the full potential of computer games in areas other than entertainment, it will be necessary to reduce the high cost associated with their design and development and to put their production directly into the hands of the domain experts. Although these experts might be interested in integrating games in their activities, they normally do not have the required technical background to create or adapt games to their needs. We propose to tackle the complexity of game design, and thereby facilitate end user design, by defining the games as a combination of more simple games following a combinatorial creativity approach. This approach does not impose the cognitive overload of learning a new design language. In addition, it might also speed up the description of the games insofar as designers do not start from scratch, trying to match their ideas with game components, but they rely upon a set of archetypical games they can combine to reach their goals. The design technique is complemented with a game platform that offers a set of authoring tools for describing game designs that can be exported to XML files, and a game engine able to interpret such files and automatically generate a 3D virtual environment in which the games can be played. In this way, designers can envision games they will be able to design in an iterative way and play the games they design to assess their validity. The proposed combinatorial approach has been evaluated in two focus group experiences that validate its feasibility and acceptability both by technical and non-technical users.\",\n \"Title: ECCE Toolkit: Prototyping Sensor-Based Interaction.\\nYear: 2017\\n\\nAbstract: Building and exploring physical user interfaces requires high technical skills and hours of specialized work. The behavior of multiple devices with heterogeneous input/output channels and connectivity has to be programmed in a context where not only the software interface matters, but also the hardware components are critical (e.g., sensors and actuators). Prototyping physical interaction is hindered by the challenges of: (1) programming interactions among physical sensors/actuators and digital interfaces; (2) implementing functionality for different platforms in different programming languages; and (3) building custom electronic-incorporated objects. We present ECCE (Entities, Components, Couplings and Ecosystems), a toolkit for non-programmers that copes with these issues by abstracting from low-level implementations, thus lowering the complexity of prototyping small-scale, sensor-based physical interfaces to support the design process. A user evaluation provides insights and use cases of the kind of applications that can be developed with the toolkit.\",\n \"Title: A Digital Knowledge Ecosystem To Increase Participation In Emergency Warnings And Alerts Management\\nYear: 2017\\n\\nAbstract: Early warning contributes to reduce the damages when updated and reliable information is collected before a hazard happens, so that early response can be orchestrated. Integrating volunteers and citizens into data collection can help to get a better picture of the situation, since they are intelligent sensors equipped with mobile devices that can be used everywhere to collect and share information. In this paper we discuss the architecture of a digital knowledge ecosystem to support such participatory early warning process. This DKE deals with a complex knowledge coproduction problem by separating information according to its meaning, quality and reliability. The use of technological tools is aimed at supporting a self-organized, scalable and sustainable process. The different agents and interactions involved and some design requirements are drawn from a use case in the context of the Spanish early warning system.\",\n \"Title: End-User Prototyping of Cross-Reality Environments.\\nYear: 2017\\n\\nAbstract: Building physical spaces interconnected with virtual worlds is a complex task that requires high technical knowledge and hours of programming and, as a matter of fact, is relegated to the work of expert professionals. The goal of this research is to lower the development threshold through the design of an end-user toolkit that provides a visual integrated environment for the rapid prototyping of cross-reality interactions. A user study with 8 participants showed the effectiveness of our approach and uncovered design opportunities and challenges for supporting the development of cross-reality environments.\",\n \"Title: A Virtual Reality Map Interface For Geographical Information Systems\\nYear: 2018\\n\\nAbstract: The Virtual Reality (VR) technology offers new possibilities to implement Geographical Information Systems (GIS), allowing the user to visualize and interact with map interfaces in more natural and immersive way. Moreover, they can provide the user with a wide field of view similar to the one obtained when using large displays. In this paper, we present a VR application that allows the user to display and interact with a GIS map using different types of interaction modalities.\",\n \"Title: Investigating Augmented Reality Support For Novice Users In Circuit Prototyping\\nYear: 2018\\n\\nAbstract: Building an electronic circuit is an error-prone activity for novice users; many errors can occur, such as incorrect wirings or wrong component values. This work explores the use of Augmented Reality (AR) as a technology to mitigate the issues that arise when users construct circuits. We present a study that investigates the effectiveness, usability, and cognitive load of AR visual instructions for circuit prototyping tasks. A mobile-based, window-on-the-world AR tool is compared to traditional media such as paper-based or monitor-displayed electronic drawings. Results show that superimposing components and instructions through AR reduces the number of errors, allows users to easily troubleshoot them and reduces users' mental workload.\",\n \"Title: A gamified platform for civic engagement in early warning.\\nYear: 2018\\n\\nAbstract: Nowadays pervasive devices like smartphones are extremely common and people use them at any moment to share normal and exceptional circumstances through social networks. Emergency Management (EM) organizations and small and medium enterprises have demonstrated a growing interest towards this peopleu0027s inclination and are developing smart applications to report potential risks to the authorities. In this context, a continuous collaboration between citizens and EM organizations is required to provide a better service. In this work, we describe a gamified mobile platform designed to support civic participation in early warning activities.\",\n \"Title: Exploring Interaction Mechanisms for Map Interfaces in Virtual Reality Environments.\\nYear: 2018\\n\\nAbstract: Virtual Reality (VR) technologies offer new ways to visualize and use map interfaces in Geographical Information Systems (GIS). But to explore the potential benefits that this technology might provide in this context, it is necessary to deploy an affordable interaction that is both efficient and satisfactory from the usersu0027 point of view. This work aims to provide insights on how to approach the interaction design for this type of novel interfaces. We present a study comparing the usability and performance of two popular interaction strategies: body-based interaction and device-based interaction. In the first case, users controlled the map using their own body, their hands and gaze. In the second case, they managed the application using a gamepad, the Oculus Touch®. The results suggest that controlling the map using the gamepad can improve performance of the selection task, in terms of time and error rate. Also, the usersu0027 satisfaction responses for system usability favored this interaction strategy.\",\n \"Title: The Immersive Bubble Chart: a Semantic and Virtual Reality Visualization for Big Data.\\nYear: 2018\\n\\nAbstract: In this paper, we introduce the Immersive Bubble Chart, a visualization for hierarchical datasets presented in a virtual reality (VR) world. Users get immersed into the visualization and interact with the bubbles using gestures with a view to overcoming some limitations of 2D visualizations due to the capabilities and interaction affordances of the devices. The technological advances in VR give the possibility to design malleable and extensible representations and more natural and engaging interactions. Using the Oculus Touch controllers, the users can grab and move the bubbles, throw them away or bump two of them for creating a cluster. We have tested the Immersive Bubble Chart with the hierarchical clusters of semantically related terms generated from Twitter.\",\n \"Title: Augmented Experiences in Cultural Spaces through Social Participation.\\nYear: 2018\\n\\nAbstract: Technologies such as the Internet of Things (IoT) and Social Computing offer promising opportunities to envision and shape augmented experiences in a wide variety of cultural spaces. Such interactive technologies act as a hook to attract visitor's attention, but if they do not provide opportunities to engage people in a more personal and meaningful way, they can be soon discarded. Augmented experiences need to be motivating and connect with values and expectations of visitors and institutions. In a world that is becoming more and more connected and moving towards a participatory culture, the need to participate actively to co-produce knowledge and meaning can be exploited as a powerful intrinsic motivator. In this article, we describe how the Social Display Environment (SDE) promotes participation in cultural spaces whilst keeping the physical connection with the exhibition objects. The SDE makes use of Augmented Reality (AR) technology to augment physical artifacts in an exhibition with overlays of digital information that is generated by the end user (e.g., the visitor). The prototype was exhibited in a cultural center over a weekend to investigate different dynamics in terms of content generation, visitors’ interactions and perceptions with respect to the interplay of digital information and physical artifacts. The prototype was assessed as easy to learn and useful and showed potential to promote a number of meaningful social interactions around the objects involved in the exhibition.\",\n \"Title: Improving Urban Environment Awareness Through Pervasive Ar Games\\nYear: 2018\\n\\nAbstract: Augmented Reality(1) (AR) and Pervasive games can be combined to improve citizens awareness about their urban environment. While AR will provide additional information in situ, pervasive games can be used to implement playable cities that support informal learning about the environment through ludic activities performed physically in the same environment. In this paper, we present a prototype of an AR pervasive game application for an Android device that invites citizens to play and acquire knowledge about their city.\",\n \"Title: Evaluating a pervasive game for urban awareness.\\nYear: 2018\\n\\nAbstract: The combination of augmented reality and pervasive games in urban environments can be exploited to enable situated and informal learning through ludic and engaging activities. In this research, we explore how to use such technologies to improve citizensu0027 awareness about their urban environment by means of an AR pervasive game to learn about a specific urban space. Since the game is pervasively played in a physical space, many usability issues need to be assessed before evaluating whether it can engage citizens whilst promoting some sense of urban awareness. In this paper, we introduce a usability study of the application and a preliminary set of factors to be analysed to assess user engagement.\",\n \"Title: Using a Google Glass-Based Classroom Feedback System to Improve Students to Teacher Communication.\\nYear: 2019\\n\\nAbstract: The use of augmented reality (AR) to support the learning process has been extensively researched but its use to support the teaching practice has just started to be explored. In this paper, we present a communication system that makes use of a pair of Google Glass to provide the teacher with a constant and private flow of information on the students' current knowledge. The proposed system allows the information sent by the students through their mobiles to overlap with the teachers' live vision of the class. Compared to other feedback systems like clickers or backchannel systems, this AR prototype avoids teachers diverting their gaze and interrupting the class to access the students' feedback. This supports the constant monitoring of potential comprehension problems that might otherwise be overlooked. With the aim of obtaining insights on the teachers' and students' views of the system, we conducted two studies during which the system was used in real classroom settings. The results of both studies suggest that the AR system could report benefits in terms of better communication between students and teachers, and a more adequate rhythm of the class. Also, the use of the AR system in the classroom does not necessarily constitute an element, which will distract and disrupt educational activity.\",\n \"Title: Do Low Cost Virtual Reality Devices Support Learning Acquisition?: A comparative study of two different VR devices\\nYear: 2019\\n\\nAbstract: Virtual Reality (VR) can support engaging and effective learning and current VR devices commercially available are opening up opportunities and expectations in higher education. An open research question is determining whether the fidelity of the VR device (e.g. resolution, framerate, etc.) impacts learning. This work aims to address this question by conducting a study wherein the quality of the experience and the knowledge acquired using a high fidelity (and high priced) VR headset is compared against a lower fidelity (and lower priced) VR headset. The results of the study do not reveal significant difference in spatial and experiential learning. The user satisfaction and experience are also similar regardless of the headset used.\",\n \"Title: Engaging Users with an AR Pervasive Game for Personal Urban Awareness\\nYear: 2019\\n\\nAbstract: The combination of Augmented Reality (AR) and pervasive games in urban environments offers a great opportunity for learning about a specific urban environment. Since pervasive games are played in a physical space, the user familiarity with such environment might play a key role in the user motivation and in the whole user experience. In this paper, we analyse how an augmented reality pervasive game is experienced in an urban game. The aim of the game is to engage people in informal learning activities increasing their knowledge about a specific area. We also introduce the concept of Personal Urban Awareness (PUA) as a way to represent the level at which a person feels connected and knows about a specific environment. Thus, we try to find out whether the user engagement and PUA are related. In order to research this, we run an experiment where two groups of users, familiar with the environment and not familiar with it, play the augmented reality game in an urban space. The results suggest that AR pervasive games might be a good approach to engage citizens and improve their awareness about a specific area.\",\n \"Title: A Tool for Monitoring and Controlling Standalone Immersive HCI Experiments\\nYear: 2021\\n\\nAbstract: ABSTRACT We present an open source tool which provides commonly required functionality in HCI experimental research targeted at Immersive technologies. Using the tool, researchers can monitor and control a Unity scene from a controller panel running in the web-browser. Researchers can also use the tool to track the user status (e.g. see what the user sees) and trigger the execution of remote functions (e.g. alter the Unity Scene, the objects appearing, etc.). Moreover, we show a use case to exemplify how the tool is being used to support our research regarding Immersive Multisensory Interaction in a room-sized environment.\",\n \"Title: Virtual-Reality Based Crisis Management Training for Teachers: An Overview of the VRTEACHER Project\\nYear: 2021\\n\\nAbstract: The coronavirus pandemic has created an educational crisis without precedent, posed new challenges, and highlighted the need for digital skills empowerment among teachers along with the use of technology-based approaches to support the delivery of education and ensure the future of learning. As a return to normality is far from over, the implementation of novel training approaches for teacher training is more imperative than ever. In this context, this paper presents the VRTEACHER project that aims to promote the use of digital technologies and innovative and open pedagogies as part of teachers’ training methodology. The vision of the project is to empower teacher’s skills (such as empathy, perspective-taking, self-efficacy, adaptability, etc.) and readiness related to class management in crisis situations, through Virtual Reality (VR) immersive and experiential training approaches that reflect real-life scenarios and situations. The aim and challenge of the project are not just to adapt the training provided to the digital era and connect it with new technologies but to build a holistic new approach to teacher training through the use of VR.\",\n \"Title: Comparing Visual Representations of Collaborative Map Interfaces for immersive Virtual Environments\\nYear: 2022\\n\\nAbstract: Virtual reality offers unique benefits to support remote collaboration. However, the way of representing the scenario and interacting within the team can influence the effectiveness of a collaborative task. In this context, this research explores the benefits and limitations of two different visual representations of the collaboration space, shared experience and shared workspace, in the specific case of map-based collaboration. Shared experience aims at reproducing face-to-face collaboration in a realistic way whilst shared workspace translates to the virtual world the functionalities of 2D collaborative spaces. The goal is to understand whether sophisticated interfaces with realistic avatars are necessary, or if simpler solutions might be enough to support efficient collaboration. We performed a user study (n = 24, 12 pairs) through a collaborative task with two roles in a emergency crisis intervention scenario that typically uses map-based interfaces. Despite that a shared experience scenario might provide a better personal experience to the user in terms of realism, our study provides insights that suggest that a shared workspace could be a more effective way to represent the scenario and improve the collaboration.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":140,"string":"140"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13363,"string":"13,363"}}},{"rowIdx":13364,"cells":{"question_id":{"kind":"string","value":"Yunheung Paek"},"question":{"kind":"string","value":"Generate an abstract for the title \"Restructuring Programs for High-Speed Computers with Polaris\" using the following items: 1. Automatic Parallelization \n2. Program Portability \n3. Polaris Project \n4. Parallelizing Compiler \n5. Application Codes"},"answer":{"kind":"string","value":"The ability to automatically parallelize standard programming languages results in program portability across a wide range of machine architectures. It is the goal of the Polaris project to develop a new parallelizing compiler that overcomes limitations of current compilers. While current parallelizing compilers may succeed on small kernels, they often fail to extract any meaningful parallelism from whole applications. After a study of application codes, it was concluded that by adding a few..."},"correct_answer":{"kind":"string","value":"The ability to automatically parallelize standard programming languages results in program portability across a wide range of machine architectures. It is the goal of the Polaris project to develop a new parallelizing compiler that overcomes limitations of current compilers. While current parallelizing compilers may succeed on small kernels, they often fail to extract any meaningful parallelism from whole applications. After a study of application codes, it was concluded that by adding a few..."},"documents":{"kind":"list like","value":["Title: Memory access optimization in compilation for coarse-grained reconfigurable architectures\nYear: 2011\n\nAbstract: Coarse-grained reconfigurable architectures (CGRAs) promise high performance at high power efficiency. They fulfil this promise by keeping the hardware extremely simple, and moving the complexity to application mapping. One major challenge comes in the form of data mapping. For reasons of power-efficiency and complexity, CGRAs use multibank local memory, and a row of PEs share memory access. In order for each row of the PEs to access any memory bank, there is a hardware arbiter between the memory requests generated by the PEs and the banks of the local memory. However, a fundamental restriction remains in that a bank cannot be accessed by two different PEs at the same time. We propose to meet this challenge by mapping application operations onto PEs and data into memory banks in a way that avoids such conflicts. To further improve performance on multibank memories, we propose a compiler optimization for CGRA mapping to reduce the number of memory operations by exploiting data reuse. Our experimental results on kernels from multimedia benchmarks demonstrate that our local memory-aware compilation approach can generate mappings that are up to 53% better in performance (26% on average) compared to a memory-unaware scheduler.","Title: Two versions of architectures for dynamic implied addressing mode\nYear: 2010\n\nAbstract: The complexity of today's embedded applications increases with various requirements such as execution time, code size or power consumption. To satisfy these requirements for performance, efficient instruction set design is one of the important issues because an instruction customized for specific applications can make better performance than multiple instructions in aspect of fast execution time, decrease of code size, and low power consumption. Limited encoding space, however, does not allow adding application specific and complex instructions freely to the instruction set architecture. To resolve this problem, conventional architectures increases free space for encoding by trimming excessive bits required beyond the fixed word length. This approach however shows severe weakness in terms of the complexity of compiler, code size and execution time. In this paper, we propose a new instruction encoding scheme based on the dynamic implied addressing mode (DIAM) to resolve limited encoding space and side-effect by trimming. We report our two versions of architectures to support our DIAM-based approach. In the first version, we use a special on-chip memory to store extra encoding information. In the second version, we replace the memory by a small on-chip buffer along with a special instruction. We also suggest a code generation algorithm to fully utilize DIAM. In our experiment, the architecture augmented with DIAM shows about 8% code size reduction and 18% speed up on average, as compared to the basic architecture without DIAM.","Title: Vigilare: toward snoop-based kernel integrity monitor\nYear: 2012\n\nAbstract: In this paper, we present Vigilare system, a kernel integrity monitor that is architected to snoop the bus traffic of the host system from a separate independent hardware. This snoop-based monitoring enabled by the Vigilare system, overcomes the limitations of the snapshot-based monitoring employed in previous kernel integrity monitoring solutions. Being based on inspecting snapshots collected over a certain interval, the previous hardware-based monitoring solutions cannot detect transient attacks that can occur in between snapshots. We implemented a prototype of the Vigilare system on Gaisler's grlib-based system-on-a-chip (SoC) by adding Snooper hardware connections module to the host system for bus snooping. To evaluate the benefit of snoop-based monitoring, we also implemented similar SoC with a snapshot-based monitor to be compared with. The Vigilare system detected all the transient attacks without performance degradation while the snapshot-based monitor could not detect all the attacks and induced considerable performance degradation as much as 10% in our tuned STREAM benchmark test.","Title: Iterative Algorithm for Compound Instruction Selection with Register Coalescing\nYear: 2009\n\nAbstract: A compound instruction, encoding several ALU or memory operations within an instruction word, has been regarded as an efficient way of improving performance. In the compiler for embedded processors, the code generation algorithm for compound instructions has been built by dealing mainly with instruction selection which is a crucial phase of code generation. In this paper, we propose an iterative code generation algorithm for minimizing the detrimental impact of register coalescing that is applied to the code with compound instructions generated earlier from the instruction selection phase.","Title: Unified Interprocedural Parallelism Detection\nYear: 2001\n\nAbstract: In this paper, we outline a new way of detecting parallelism interprocedurally within a program. Our method goes beyond mere dependence testing, to embrace methods of removing dependences as well, namely privatization, induction recognition and reduction recognition. This method is based on a combination of techniques: a “universal” form for representing memory accesses within a section of code (the Linear Memory Access Descriptor), a technique for classifying memory locations based on the accesses made to them by the code (Memory Classification Analysis), and a dependence test (the Access Region Test). The analysis done with Linear Memory Access Descriptors is based on an intersection operation, for which we present an algorithm. Linear Memory Access Descriptors are independent of any declarations that may exist in a program, so they are subroutine- and language-independent. This makes them ideal for use in interprocedural analysis. Our experiments indicate that this test is highly effective for parallelizing loops containing very complex subscript expressions.","Title: Parallel Programming with Polaris\nYear: 1996\n\nAbstract: As we reach the technological limits of hardware improvement, we must rely on multiple processors to improve programming speed. Parallel programming tools are limited, making effective parallel programming difficult and cumbersome. Compilers that translate conventional sequential programs into parallel form would liberate programmers from the complexities of explicit, machine-oriented parallel programming. Polaris, an experimental translator of conventional Fortran programs that target machines such as the Cray T3D, is the first step toward this goal. The most important techniques implemented in Polaris resulted from a study of the effectiveness of commercial Fortran parallelizers. The authors compiled the Perfect Benchmarks, a collection of conventional Fortran programs representing the typical workload of high-performance computers, for the Alliant FX/80, an eight-processor multiprocessor popular in the late 1980s. For each program, they measured the quality of the parallelization by computing the speedup. With few exceptions, the Alliant Fortran compiler failed to deliver any significant speedup for the majority of the programs. The compiler failed to produce a speedup because it could not parallelize some of the most important loops in the Perfect Benchmarks. The study showed that extending the four most important analysis and transformation techniques traditionally used for vectorization leads to significant increases in speedup. Polaris detected much of the parallelism available in the set of benchmark codes. A careful analysis of the remaining loops that Polaris could parallelize highlights four areas for improvement.","Title: Case Studies on Automatic Extraction of Target-Specific Architectural Parameters in Complex Code Generation\nYear: 2003\n\nAbstract: To cope with the highly complex and irregular embedded processor architectures, we employ the two traditionally-known most aggressive and computationally expensive code generation methods. One is integrated code generation where two main subproblems of code generation, instruction selection and register allocation, are simultaneously solved. The other is directed acyclic graph (DAG) covering, not tree covering, for code generation. In principle, unifying these two expensive methods may increase compilation time prohibitively. However often in practice, we have observed that the overall time can be manageably short without degrading the code quality by adding a few heuristics that fully capitalize on specific characteristics of target processor models.","Title: Exploiting both pipelining and data parallelism with SIMD reconfigurable architecture\nYear: 2012\n\nAbstract: Reconfigurable Architecture (RA), which provides extremely high energy efficiency for certain domains of applications, have one problem that current mapping algorithms for it do not scale well with the number of cores. One approach to this problem is using SIMD (Single Instruction Multiple Data) paradigm. However, SIMD can complicate the mapping problem by adding an additional dimension, i.e., iteration mapping, to the already inter-dependent problems of data mapping and operation mapping, and can significantly affect performance through memory bank conflicts. In this paper we introduce SIMD reconfigurable architecture, which allows for SIMD mapping at multiple levels of granularity, and investigate ways to minimize bank conflicts in a SIMD reconfigurable architecture with the related sub-problems taken into consideration. We further present data tiling and evaluate a conflict-free scheduling algorithm as a way to eliminate bank conflicts for a certain class of iteration and data mapping.","Title: Automatic generation of operation tables for fast exploration of bypasses in embedded processors\nYear: 2006\n\nAbstract: Customizing the bypasses in an embedded processor uncovers valuable trade-offs between the power, performance and the cost of the processor. Meaningful exploration of bypasses requires bypass-sensitive compiler. Operation tables (OTs) have been proposed to perform bypass-sensitive compilation. However, due to lack of automated methods to generate OTs, OTs are currently manually specified by the designer. Manual specification of OTs is not only an extremely time consuming task, but is also highly error-prone. In this paper, we present AutoOT, an algorithm to automatically generate OTs from a high-level processor description. Our experiments on the Intel XScale processor model running MiBench benchmarks demonstrate that AutoOT greatly reduces the time and effort of specification. Automatic generation of OTs makes it feasible to perform full bypass exploration on the Intel XScale and thus discover interesting alternate bypass configurations in a reasonable time. To further reduce the compile-time overhead of OT generation, we propose another novel algorithm, AutoOTDB. AutoOTDB is able to cut the compile-time overhead of OT generation by half","Title: Automatic Parallelization for Non-cache Coherent Multiprocessors\nYear: 1996\n\nAbstract: Abstract: Although much work has been done on parallelizing compilers for cachecoherent shared memory multiprocessors and message-passing multiprocessors,there is relatively little research on parallelizing compilers for noncachecoherent multiprocessors with global address space. In this paper,we present a preliminary study on automatic parallelization for the CrayT3D, a commercial scalable machine with a global memory space and noncoherentcaches.","Title: Fast graph-based instruction selection for multi-output instructions\nYear: 2011\n\nAbstract: A multi-output instruction (MOI) is an instruction that produces multiple outputs to its destination locations. Such inherently parallel instructions are becoming more and more popular in embedded processors, due to the advances in application-specific architectures. In order to provide high-level programmability and thus guarantee widespread acceptance, sophisticated compiler support for these programmable cores is necessary. However, traditional tree-based approaches for instruction selection, although very fast, fail to exploit MOIs mainly because of the fundamental limitation of the tree representation. In fact, to generate optimal code with MOIs requires a more general graph-based formulation of the instruction selection problem, which is at least NP-complete. In this paper we present a new methodology to automatically generate from simple instruction set descriptions, graph-based code selectors that can effectively utilize all provided instructions including MOIs. Our experimental results using a set of benchmarks on a target processor with various MOIs of up to two outputs demonstrate that our generated code selectors can quickly and effectively exploit many MOIs at the application level, and therefore are highly desirable both for architecture exploration and as code generators after architecture is fixed. Copyright © 2010 John Wiley & Sons, Ltd. (This is a revised and expanded version of a paper published in the Fifth IEEE/ACM International Conference on Hardware/Software Codesign and System Synthesis (CODES+ISSS), September 2007 1.)","Title: Compiler Techniques for Effective Communication on Distributed-Memory Multiprocessors\nYear: 1997\n\nAbstract: The Polaris restructurer transforms conventional Fortran programs into parallel form for various types of multiprocessor systems. This paper presents the results of a study on strategies to improve the effectiveness of Polaris' techniques for distributed-memory multiprocessors. Our study, which is based on the hand analysis of MDG and TRFD from the Perfect Benchmarks and TOMCATV and SWIM from SPEC benchmarks, identified three techniques that are important for improving communication optimization. Their application produces almost perfect speedups for the four programs on the Cray T3D.","Title: Reducing instruction bit-width for low-power VLIW architectures\nYear: 2013\n\nAbstract: VLIW (very long instruction word) architectures have proven to be useful for embedded applications with abundant instruction level parallelism. But due to the long instruction bus width it often consumes more power and memory space than necessary. One way to lessen this problem is to adopt a reduced bit-width instruction set architecture (ISA) that has a narrower instruction word length. This facilitates a more efficient hardware implementation in terms of area and power by decreasing bus-bandwidth requirements and the power dissipation associated with instruction fetches. In practice, however, it is impossible to convert a given ISA fully into an equivalent reduced bit-width one because the narrow instruction word, due to bit-width restrictions, can encode only a small subset of normal instructions in the original ISA. Consequently, existing processors provide narrow instructions in very limited cases along with severe restrictions on register accessibility. The objective of this work is to explore the possibility of complete conversion, as a case study, of an existing 32-bit VLIW ISA into a 16-bit one that supports effectively all 32-bit instructions. To this objective, we attempt to circumvent the bit-width restrictions by dynamically extending the effective instruction word length of the converted 16-bit operations. Further, we will show that our proposed ISA conversion can create a synergy effect with a VLES (variable length execution set) architecture that is adopted in most recent VLIW processors. According to our experiment, the code size becomes significantly smaller after the conversion to 16-bit VLIW code. Also at a slight run time cost, the machine with the 16-bit ISA consumes much less energy than the original machine.","Title: Architecture customization of on-chip reconfigurable accelerators\nYear: 2013\n\nAbstract: Integrating coarse-grained reconfigurable architectures (CGRAs) into a System-on-a-Chip (SoC) presents many benefits as well as important challenges. One of the challenges is how to customize the architecture for the target applications efficiently and effectively without performing explicit design space exploration. In this article we present a novel methodology for incremental interconnect customization of CGRAs that can suggest a new interconnection architecture which is able to maximize the performance for a given set of application kernels while minimizing the hardware cost. In our methodology, we translate the problem of interconnect customization into that of inexact graph matching, and we devised a heuristic for A* search algorithm to efficiently solve the inexact graph matching problem. Our experimental results demonstrate that our customization method can quickly find application-optimized interconnections that exhibit 80% higher performance on average compared to the base architecture which has mesh interconnections, with little energy and hardware increase in interconnections and muxes.","Title: A retargetable parallel-programming framework for MPSoC\nYear: 2008\n\nAbstract: As more processing elements are integrated in a single chip, embedded software design becomes more challenging: It becomes a parallel programming for nontrivial heterogeneous multiprocessors with diverse communication architectures, and design constraints such as hardware cost, power, and timeliness. In the current practice of parallel programming with MPI or OpenMP, the programmer should manually optimize the parallel code for each target architecture and for the design constraints. Thus, the design-space exploration of MPSoC (multiprocessor systems-on-chip) costs become prohibitively large as software development overhead increases drastically. To solve this problem, we develop a parallel-programming framework based on a novel programming model called common intermediate code (CIC). In a CIC, functional parallelism and data parallelism of application tasks are specified independently of the target architecture and design constraints. Then, the CIC translator translates the CIC into the final parallel code, considering the target architecture and design constraints to make the CIC retargetable. Experiments with preliminary examples, including the H.263 decoder, show that the proposed parallel-programming framework increases the design productivity of MPSoC software significantly.","Title: A graph drawing based spatial mapping algorithm for coarse-grained reconfigurable architectures\nYear: 2009\n\nAbstract: Recently coarse-grained reconfigurable architectures (CGRAs) have drawn increasing attention due to their efficiency and flexibility. While many CGRAs have demonstrated impressive performance improvements, the effectiveness of CGRA platforms ultimately hinges on the compiler. Existing CGRA compilers do not model the details of the CGRA, and thus they are i) unable to map applications, even though a mapping exists, and ii) using too many processing elements (PEs) to map an application. In this paper, we model several CGRA details, e.g., irregular CGRA topologies, shared resources and routing PEs in our compiler and develop a graph drawing based approach, Split-Push Kernel Mapping (SPKM), for mapping applications onto CGRAs. On randomly generated graphs our technique can map on average 4.5× more applications than the previous approach, while generating mappings which have better qualities in terms of utilized CGRA resources. Utilizing fewer resources is directly translated into increased opportunities for novel power and performance optimization techniques. Our technique shows less power consumption in 71 cases and shorter execution cycles in 66 cases out of 100 synthetic applications, with minimum mapping time overhead. We observe similar results on a suite of benchmarks collected from Livermore loops, Mediabench, Multimedia, Wavelet and DSPStone benchmarks. SPKM is not a customized algorithm only for a specific CGRA template, and it is demonstrated by exploring various PE interconnection topologies and shared resource configurations with SPKM.","Title: Operation and data mapping for CGRAs with multi-bank memory\nYear: 2010\n\nAbstract: Coarse Grain Reconfigurable Architectures (CGRAs) promise high performance at high power efficiency. They fulfil this promise by keeping the hardware extremely simple, and moving the complexity to application mapping. One major challenge comes in the form of data mapping. For reasons of power-efficiency and complexity, CGRAs use multi-bank local memory, and a row of PEs share memory access. In order for each row of the PEs to access any memory bank, there is a hardware arbiter between the memory requests generated by the PEs and the banks of the local memory. However, a fundamental restriction remains that a bank cannot be accessed by two different PEs at the same time. We propose to meet this challenge by mapping application operations onto PEs and data into memory banks in a way that avoids such conflicts. Our experimental results on kernels from multimedia benchmarks demonstrate that our local memory-aware compilation approach can generate mappings that are up to 40% better in performance (17.3% on average) compared to a memory-unaware scheduler.","Title: A Study on Data Allocation of On-Chip Dual Memory Banks\nYear: 2002\n\nAbstract: Embedded systems require control of many concurrent real-time activities, leading to system designs which feature multiple hardware peripherals with each providing a specific, dedicated service. These peripherals increase system size, cost, weight, power ...","Title: Memory-Aware application mapping on coarse-grained reconfigurable arrays\nYear: 2010\n\nAbstract: Coarse-Grained Reconfigurable Arrays (CGRAs) are a very promising platform, providing both, up to 10-100 MOps/mW of power efficiency and are software programmable. However, this cardinal promise of CGRAs critically hinges on the effectiveness of application mapping onto CGRA platforms. While previous solutions have greatly improved the computation speed, they have largely ignored the impact of the local memory architecture on the achievable power and performance. This paper motivates the need for memory-aware application mapping for CGRAs, and proposes an effective solution for application mapping that considers the effects of various memory architecture parameters including the number of banks, local memory size, and the communication bandwidth between the local memory and the external main memory. Our proposed solution achieves 62% reduction in the energy-delay product, which factors into about 47% and 28% reduction in the energy consumption and runtime, respectively, as compared to memory-unaware mapping for realistic local memory architectures. We also show that our scheme scales across a range of applications, and memory parameters.","Title: Efficient embedded code generation with multiple load-store instructions\nYear: 2007\n\nAbstract: In a recent study, we discovered that many single load-store operations in embedded applications can be parallelized and thus encoded simultaneously in a single-instruction multiple-data instruction, called the multiple load-store (MLS) instruction. In this work, we investigate the problem of utilizing MLS instructions to produce optimized machine code, and propose an effective approach to the problem. Specifically, we formalize the MLS problem, that is, the problem of maximizing the use of MLS instructions with an unlimited register file size. Based on this analysis, we show that we can solve the problem efficiently by translating it into a variant of the problem finding a maximum weighted path cover in a dynamic weighted graph. To handle a more realistic case of the finite size of the register file, our solution is then extended to take into account the constraints of register sequencing in MLS instructions and the limited register resource available in the target processor. We demonstrate the effectiveness of our approach experimentally by using a set of benchmark programs. In summary, our approach can reduce the number of loads-stores by 13.3% on average, compared with the code generated from existing compilers. The total code size reduction is 3.6%. This code size reduction comes at almost no cost because the overall increase in compilation time as a result of our technique remains quite minimal. Copyright © 2007 John Wiley & Sons, Ltd.","Title: Fast dynamic execution offloading for efficient mobile cloud computing\nYear: 2013\n\nAbstract: In order to meet the increasing demand for high performance in smartphones, recent studies suggested mobile cloud computing techniques that aim to connect the phones to adjacent powerful cloud servers to throw their computational burden to the servers. These techniques often employ execution offloading schemes that migrate a process between machines during its execution. In execution offloading, code regions to be executed on the server are decided statically or dynamically based on the complex analysis on execution time and process state transfer time of every region. Expectedly, the transfer time is a deciding factor for the success of execution offloading. According to our analysis, it is dominated by the total size of heap objects transferred over the network. But previous work did not try hard to minimize this size. Thus in this paper, we introduce novel techniques based on compiler code analysis that effectively reduce the transferred data size by transferring only the essential heap objects. The experiments exhibit that the reduced size positively influences not only the transfer time itself but also the overall effectiveness of execution offloading, and ultimately, improves the performance of our mobile cloud computing significantly in terms of execution time and power consumption.","Title: Adaptive Scratch Pad Memory Management for Dynamic Behavior of Multimedia Applications\nYear: 2009\n\nAbstract: Exploiting runtime memory access traces can be a complementary approach to compiler optimizations for the energy reduction in memory hierarchy. This is particularly important for emerging multimedia applications since they usually have input-sensitive runtime behavior which results in dynamic and/or irregular memory access patterns. These types of applications are normally hard to optimize by static compiler optimizations. The reason is that their behavior stays unknown until runtime and may even change during computation. To tackle this problem, we propose an integrated approach of software [compiler and operating system (OS)] and hardware (data access record table) techniques to exploit data reusability of multimedia applications in Multiprocessor Systems on Chip. Guided by compiler analysis for generating scratch pad data layouts and hardware components for tracking dynamic memory accesses, the scratch pad data layout adapts to an input data pattern with the help of a runtime scratch pad memory manager incorporated in the OS. The runtime data placement strategy presented in this paper provides efficient scratch pad utilization for the dynamic applications. The goal is to minimize the amount of accesses to the main memory over the entire runtime of the system, which leads to a reduction in the energy consumption of the system. Our experimental results show that our approach is able to significantly improve the energy consumption of multimedia applications with dynamic memory access behavior over an existing compiler technique and an alternative hardware technique.","Title: A Parallel Programming Environment for a V-Busbased PC-cluster\nYear: 2001\n\nAbstract: Nowadays PC-cluster architectures are widely accepted forparallel computing.In a PC-cluster system, memories are physicallydistributed.To harness thecomputational power of a distributed-memoryPC-cluster, a user must writeefficient software for the machine by hand. The absence of globaladdress space makes the process laborious because theuser must manually assign computations to processors, distribute data acrossprocessors andexplicitly manage communication among processors. This paperintroduces ourrecent three related studies on parallel computing. The first isem a V-Busbased PC-cluster in which all PCs are interconnected through V-Busnetworkcards. The second is the implementation of an one-sidedcommunicationlibrary on our PC-cluster system, which provides the user with aview ofglobal address space on top of the distributed-memory PC-cluster.Thisencapsulation of global address allows the user to write shared memory codeonour cluster system, which simplifies programming our cluster because theuserdoes not need to explicitly cope with distributed memories. The third is aparallelizing compiler that automatically translates a sequential code toashared-memory code for the PC-cluster. This compiler not only enables legacycodeto be compiled for our cluster, but also further simplifies programmingourcluster by allowing the user to continue using conventional sequentiallanguagessuch as Fortran 77.In this work, the compiler was optimizedparticularlyfor our V-Bus based PC-cluster. The paper also reports ourexperimental resultswith the compiler on our PC-cluster system.","Title: Compiling for Scalable Multiprocessors with Polaris\nYear: 1997\n\nAbstract: yThe lack of cache coherence mechanisms introducessome challenges to the programming of distributedmemory machines with a globally addressable memory.The reason is that, in these machines, softwareneeds explicit control of cacheability and coherency. Tosimplify programming, and increase reliability and reducedevelopment costs as a consequence, it is necessaryto automatically generate the statements that controlcacheability and coherency. To generate these statements,a compiler needs...","Title: Software controlled memory layout reorganization for irregular array access patterns\nYear: 2007\n\nAbstract: Many embedded array-intensive applications have irregular access patterns that are not amenable to static analysis for extraction of access patterns, and thus prevent efficient use of a Scratch Pad Memory (SPM) hierarchy for performance and power improvement. We present a profiling based strategy that generates a memory access trace which can be used to identify data elements with fine granularity that can profitably be placed in the SPMs to maximize performance and energy gains. We developed an entire toolchain that allows incorporation of the code required to profitably move data to SPMs; visualization of the extracted access pattern after profiling; and evaluation/exploration of the generated application code to steer mapping of data to the SPM to yield performance and energy benefits.We present a heuristic approach that efficiently exploits the SPM using the profiler-driven access pattern behaviors. Experimental results on EEMBC and other industrial codes obtained with our framework show that we are able to achieve 36% energy reduction and reduce execution time by up to 22% compared to a cache based system.","Title: Selective validations for efficient protections on Coarse-Grained Reconfigurable Architectures\nYear: 2013\n\nAbstract: Coarse-Grained Reconfigurable Architectures or CGRAs are drawing significant attention since they promise both performance with parallelism and flexibility with reconfiguration. Soft errors or transient faults are becoming a serious design concern in embedded systems including CGRAs since soft error rate is increasing exponentially as technology scaling. A recently proposed software-based technique with TMR (Triple Modular Redundancy) implemented on CGRAs incurs extreme performance overhead mainly due to expensive voting mechanisms for outputs from triplication of every operation. In this paper, we propose selective validation mechanisms for efficient modular redundancy techniques in the datapaths on CGRAs. Our techniques selectively validate results at synchronous operations rather than every operation in order to reduce the expensive performance overhead from the validation mechanism. Our experimental results demonstrate that our selective validation based TMR technique can improve the performance by 38.3% on average over benchmarks as compared to the recently proposed software-based TMR technique with the full validation.","Title: Efficient register and memory assignment for non-orthogonal architectures via graph coloring and MST algorithms\nYear: 2002\n\nAbstract: Finding an optimal assignment of program variables into registers and memory is prohibitively difficult in code generation for application specific instruction-set processors (ASIPs). This is mainly because, in order to meet stringent speed and power requirements for embedded applications, ASIPs commonly employ non-orthogonal architectures which are typically characterized by irregular data paths, heterogeneous registers and multiple memory banks. As a result, existing techniques mainly developed for relatively regular, orthogonal general-purpose processors (GPPs) are obsolete for these recently emerging ASIP architectures. In this paper, we attempt to tackle this issue by exploiting conventional graph coloring and maximum spanning tree (MST) algorithms with special constraints added to handle the non-orthogonality of ASIP architectures. The results in our study indicate that our algorithm finds a fairly good assignment of variables into heterogeneous registers and multi-memories while it runs extremely faster than previous work that employed exceedingly expensive algorithms to address this issue.","Title: High Throughput Data Mapping for Coarse-Grained Reconfigurable Architectures\nYear: 2011\n\nAbstract: Coarse-grained reconfigurable arrays (CGRAs) are a very promising platform, providing both up to 10–100 MOps/mW of power efficiency and software programmability. However, this promise of CGRAs critically hinges on the effectiveness of application mapping onto CGRA platforms. While previous solutions have greatly improved the computation speed, they have largely ignored the impact of the local memory architecture on the achievable power and performance. This paper motivates the need for memory-aware application mapping for CGRAs, and proposes an effective solution for application mapping that considers the effects of various memory architecture parameters including the number of banks, local memory size, and the communication bandwidth between the local memory and the external main memory. Further we propose efficient methods to handle dependent data on a double-buffering local memory, which is necessary for recurrent loops. Our proposed solution achieves 59% reduction in the energy-delay product, which factors into about 47% and 22% reduction in the energy consumption and runtime, respectively, as compared to memory-unaware mapping for realistic local memory architectures. We also show that our scheme scales across a range of applications and memory parameters, and the runtime overhead of handling recurrent loops by our proposed methods can be less than 1%.","Title: Hiding cache miss penalty using priority-based execution for embedded processors\nYear: 2008\n\nAbstract: The contribution of memory latency to execution time continues to increase, and latency hiding mechanisms become ever more important for efficient processor design. While high-end processors can use elaborate techniques like multiple issue, out-of-order execution, speculative execution, value prediction etc. to tolerate high memory latencies, they are often not viable solutions for embedded processors, due to significant area, power and chip complexity overheads. This paper proposes a hardware-software cooperative approach, called priority-based execution to hide cache miss penalty for embedded processors. The compiler classifies the instructions into low-priority and high-priority instructions. The processor executes the high-priority instructions, but delays the execution of low priority instructions. They are executed on a cache miss to hide the cache miss penalty. We empirically evaluate our proposal on the Intel XScale compiler and microarchitecture. Experimental results on bench-marks from Multimedia, Media Bench, MiBench, and SPEC2000 demonstrate an average 17% performance improvements, hiding 75% cache miss penalty.","Title: Exploiting parallelism in memory operations for code optimization\nYear: 2004\n\nAbstract: Code size reduction is ever becoming more important for compilers targeting embedded processors because these processors are often severely limited by storage constraints and thus the reduced code size can have a positively significant impact on their performance. Various code size reduction techniques have different motivations and a variety of application contexts utilizing special hardware features of their target processors. In this work, we propose a novel technique that fully utilizes a set of hardware instructions, called the multiple load/store (MLS) or parallel load/store (PLS), that are specially featured for reducing code size by minimizing the number of memory operations in the code. To take advantage of this feature, many microprocessors support the MLS instructions, whereas no existing compilers fully exploit the potential benefit of these instructions but only use them for some limited cases. This is mainly because optimizing memory accesses with MLS instructions for general cases is an NP-hard problem that necessitates complex assignments of registers and memory offsets for variables in a stack frame. Our technique uses a couple of heuristics to efficiently handle this problem in a polynomial time bound.","Title: Simplification of array access patterns for compiler optimizations\nYear: 1998\n\nAbstract: Existing array region representation techniques are sensitive to the complexity of array subscripts. In general, these techniques are very accurate and efficient for simple subscript expressions, but lose accuracy or require potentially expensive algorithms for complex subscripts. We found that in scientific applications, many access patterns are simple even when the subscript expressions are complex. In this work, we present a new, general array access representation and define operations for it. This allows us to aggregate and simplify the representation enough that precise region operations may be applied to enable compiler optimizations. Our experiments show that these techniques hold promise for speeding up applications.","Title: Run-Time memory optimization for DDMB architecture through a CCB algorithm\nYear: 2006\n\nAbstract: Most vendors of digital signal processors (DSPs) support a Harvard architecture, which has two or more memory buses, one for program and one or more for data and allow the processor to access multiple words of data from memory in a single instruction cycle. We already addressed how to efficiently assign data to multi-memory banks in our previous work. This paper reports on our recent attempt to optimize run-time memory. The run-time environment for dual data memory banks (DDMBs) requires two run-time stacks to control activation records located in two memory banks corresponding to calling procedures. However, activation records of two memory banks for a procedure are able to have different size. As a consequence, dual run-time stacks can be unbalanced whenever a procedure is called. This unbalance between two memory banks causes that usage of one memory bank can exceed the extent of on-chip memory area although there is free area in the other memory bank. We attempt balancing dual run-time stacks to enhance efficiently utilization of on-chip memory in this paper. The experimental results have revealed that although our call chain balancing (CCB) algorithm is relatively quite simple, it still can utilize run-time memories efficiently; thus enabling our compiler to run extremely fast, yet minimizing the usage of run-time memory in the target code.","Title: SPKM: a novel graph drawing based algorithm for application mapping onto coarse-grained reconfigurable architectures\nYear: 2008\n\nAbstract: Recently coarse-grained reconfigurable architectures (CGRAs) have drawn increasing attention due to their efficiency and flexibility. While many CGRAs have demonstrated impressive performance improvements, the effectiveness of CGRA platforms ultimately hinges on the compiler. Existing CGRA compilers do not model the details of the CGRA architecture, due to which they are, i) unable to map applications, even though a mapping exists, and ii) use too many PEs to map an application. In this paper, we model several CGRA details in our compiler and develop a graph mapping based approach (SPKM) for mapping applications onto CGRAs. On randomly generated graphs our technique can map on average 4.5X more applications than the previous approaches, while using fewer CGRA rows 62% times, without any penalty in mapping time. We observe similar results on a suite of benchmarks collected from Livermore Loops, Multimedia and DSPStone benchmarks.","Title: VISTA: VPO interactive system for tuning applications\nYear: 2006\n\nAbstract: Software designers face many challenges when developing applications for embedded systems. One major challenge is meeting the conflicting constraints of speed, code size, and power consumption. Embedded application developers often resort to hand-coded assembly language to meet these constraints since traditional optimizing compiler technology is usually of little help in addressing this challenge. The results are software systems that are not portable, less robust, and more costly to develop and maintain. Another limitation is that compilers traditionally apply the optimizations to a program in a fixed order. However, it has long been known that a single ordering of optimization phases will not produce the best code for every application. In fact, the smallest unit of compilation in most compilers is typically a function and the programmer has no control over the code improvement process other than setting flags to enable or disable certain optimization phases. This paper describes a new code improvement paradigm implemented in a system called VISTA that can help achieve the cost/performance trade-offs that embedded applications demand. The VISTA system opens the code improvement process and gives the application programmer, when necessary, the ability to finely control it. VISTA also provides support for finding effective sequences of optimization phases. This support includes the ability to interactively get static and dynamic performance information, which can be used by the developer to steer the code improvement process. This performance information is also internally used by VISTA for automatically selecting the best optimization sequence from several attempted. One such feature is the use of a genetic algorithm to search for the most efficient sequence based on specified fitness criteria. We include a number of experimental results that evaluate the effectiveness of using a genetic algorithm in VISTA to find effective optimization phase sequences.","Title: Register File Power Reduction Using Bypass Sensitive Compiler\nYear: 2008\n\nAbstract: This paper explores, develops, and investigates several bypass-sensitive compilation techniques to reduce the register file power by reducing the access frequency to the register file. We study the effectiveness of our techniques on the Intel XScale processor, which is based on the previously proposed ldquoon-demand register fetch readrdquo architectural feature. Furthermore, we show that our bypass-sensitive compilation technique is effective on various partial bypass configurations.","Title: Improving performance of loops on DIAM-based VLIW architectures\nYear: 2014\n\nAbstract: Recent studies show that very long instruction word (VLIW) architectures, which inherently have wide datapath (e.g. 128 or 256 bits for one VLIW instruction word), can benefit from dynamic implied addressing mode (DIAM) and can achieve lower power consumption and smaller code size with a small performance overhead. Such overhead, which is claimed to be small, is mainly caused by the execution of additionally generated special instructions for conveying information that cannot be encoded in reduced instruction bit-width. In this paper, however, we show that the performance impact of applying DIAM on VLIW architecture cannot be overlooked expecially when applications possess high level of instruction level parallelism (ILP), which is mostly the case for loops because of the result of aggressive code scheduling. We also propose a way to relieve the performance degradation especially focusing on loops since loops spend almost 90% of total execution time in programs and tend to have high ILP. We first implement the original DIAM compilation technique in a compiler, and augment it with the proposed loop optimization scheme to show that ours can clearly alleviate the performance loss caused by the excessive number of additional instructions, with the help of slightly modified hardware. Moreover, the well-known loop unrolling scheme, which would produce denser code in loops at the cost of substantial code size bloating, is integrated into our compiler. The experiment result shows that the loop unrolling technique, combined with our augmented DIAM scheme, produces far better code in terms of performance with quite an acceptable amount of code increase.","Title: Instruction re-selection for iterative modulo scheduling on high performance multi-issue DSPs\nYear: 2006\n\nAbstract: An iterative modulo scheduling is very important for compilers targeting high performance multi-issue digital signal processors. This is because these processors are often severely limited by idle state functional units and thus the reduced idle units can have a positively significant impact on their performance. However, complex instructions, which are used in most recent DSPs such as mac, usually increase data dependence complexity, and such complex dependencies that exist in signal processing applications often restrict modulo scheduling freedom and therefore, become a limiting factor of the iterative modulo scheduler. In this work, we propose a technique that efficiently reselects instructions of an application loop code considering dependence complexity, which directly resolve the dependence constraint. That is specifically featured for accelerating software pipelining performance by minimizing length of intrinsic cyclic dependencies. To take advantage of this feature, few existing compilers support a loop unrolling based dependence relaxing technique, but only use them for some limited cases. This is mainly because the loop unrolling typically occurs an overhead of huge code size increment, and the iterative modulo scheduling with relaxed dependence techniques for general cases is an NP-hard problem that necessitates complex assignments of registers and functional units. Our technique uses a heuristic to efficiently handle this problem in pre-stage of iterative modulo scheduling without loop unrolling.","Title: Preprocessing strategy for effective modulo scheduling on multi-issue digital signal processors\nYear: 2007\n\nAbstract: To achieve high resource utilization for multi-issue Digital Signal Processors (DSPs), production compilers commonly include variants of the iterative modulo scheduling algorithm. However, excessive cyclic data dependences, which exist in communication and media processing loops, often prevent the modulo scheduler from achieving ideal loop initiation intervals. As a result, replicated functional units in multi-issue DSPs are frequently underutilized. In response to this resource underutilization problem, this paper describes a compiler preprocessing strategy that capitalizes on two techniques for effective modulo scheduling, referred to as cloning1 and cloning2. The core of the proposed techniques lies in the direct relaxation of cyclic data dependences by exploiting functional units which are otherwise left unused. Since our preprocessing strategy requires neither code duplication nor additional hardware support, it is relatively easy to implement in DSP compilers. The strategy proposed has been validated by an implementation for a StarCore SC140 optimizing C compiler.","Title: Power-Conscious Configuration Cache Structure and Code Mapping for Coarse-Grained Reconfigurable Architecture\nYear: 2006\n\nAbstract: Coarse-grained reconfigurable architecture aims to achieve both performance and flexibility. However, power consumption is no less important for the reconfigurable architecture to be used as a competitive processing core in embedded systems. In this paper, we show how power is consumed in a typical coarse-grained reconfigurable architecture. Based on the power breakdown data, we suggest a power-conscious configuration cache structure and code mapping technique, which reduce power consumption without performance degradation. Experimental results show that the proposed approach saves much power even with reduced configuration cache size","Title: Compiler-in-the-loop design space exploration framework for energy reduction in horizontally partitioned cache architectures\nYear: 2009\n\nAbstract: Horizontally partitioned caches (HPCs) are a power-efficient architectural feature in which the processor maintains two or more data caches at the same level of hierarchy. HPCs help reduce cache pollution and thereby improve performance. Consequently, most previous research has focused on exploiting HPCs to improve performance and achieve energy reduction only as a byproduct of performance improvement. However, with energy consumption becoming the first class design constraint, there is an increasing need for compilation techniques aimed at energy reduction itself. This paper proposes and explores several low-complexity algorithms aimed at reducing the energy consumption. Acknowledging that the compiler has a significant impact on the energy consumption of the HPCs, Compiler-in-the-Loop Design Space Exploration methodologies are also presented to carefully choose the HPC parameters that result in minimum energy consumption for the application.","Title: Fast Code Generation for Embedded Processors with Aliased Heterogeneous Registers\nYear: 2009\n\nAbstract: Many embedded processors have complex, irregular architectures resulting from the customization for the maximum performance and energy efficiency of target applications. One such example is the heterogeneous register architecture, which has fast, small-sized register files, for their specific uses, distributed over the data paths between different functional units. Although this architectural design may be good at achieving the H/W design goal of high speed, small area and low power, it requires highly expensive algorithms for optimal code generation. This is primarily because multiple registers contained in each file come with many different constraints subject to their design purposes, and often their names are aliased with each other; thus the final code quality is very sensitive to how properly such aliased, heterogeneous registers are utilized in every instruction. In this work, we propose a code generation approach to attack this complex problem. The experiments reveal that our approach is fast, practically running in polynomial time. In comparison with the related work, it achieves approximately 13% of code size reduction and 16% of speed increase.","Title: The very portable optimizer for digital signal processors\nYear: 2001\n\nAbstract: Although retargetability has been a major design concern for many compilers, retargetability is a vitally important issue for Digital Signal Processors(DSPs) because the architectural variations of DSPs are much wider than those of General-Purpose Processors (GPPs). This paper describes our preliminary study on a retargetable code generator, called the Very Portable Optimizer (VPO), that has been recently engineered to target DSPs. The compiler was originally implemented to target GPPs, but thanks to its novel intermediate representation designed to support retargetability, it has been successfully retargeted to a commercial DSP within a relatively short period of time. This retargetable compiler study is at its early stage, so the code quality is still amenable to further improvement. However, our recent enhancements to VPO helped us to achieve quite encouraging results when being compared with a production-quality, highly-customized, compiler.","Title: Mantis: automatic performance prediction for smartphone applications\nYear: 2013\n\nAbstract: We present Mantis, a framework for predicting the performance of Android applications on given inputs automatically, accurately, and efficiently. A key insight underlying Mantis is that program execution runs often contain features that correlate with performance and are automatically computable efficiently. Mantis synergistically combines techniques from program analysis and machine learning. It constructs concise performance models by choosing from many program execution features only a handful that are most correlated with the program's execution time yet can be evaluated efficiently from the program's input. We apply program slicing to accurately estimate the evaluation cost of a feature and automatically generate executable code snippets for efficiently evaluating features. Our evaluation shows that Mantis predicts the execution time of six Android apps with estimation error in the range of 2.2-11.9% by executing predictor code costing at most 1.3% of their execution time on Galaxy Nexus.","Title: A spatial mapping algorithm for heterogeneous coarse-grained reconfigurable architectures\nYear: 2006\n\nAbstract: In this work, we investigate the problem of automatically mapping applications onto a coarse-grained reconfigurable architecture and propose an efficient algorithm to solve the problem. We formalize the mapping problem and show that it is NP-complete. To solve the problem within a reasonable amount of time, we divide it into three subproblems: covering, partitioning and layout. Our empirical results demonstrate that our technique produces nearly as good performance as hand-optimized outputs for many kernels","Title: Optimistic coalescing for heterogeneous register architectures\nYear: 2007\n\nAbstract: In this paper, Optimistic coalescing has been proven as an elegant and effective technique that provides better chances of safely coloring more registers in register allocation than other coalescing techniques. Its algorithm originally assumes homogeneous registers which are all gathered in the same register file. Although this register architecture is still common in most general-purpose processors, embedded processors often contain heterogeneous registers which are scattered in physically different register files dedicated for each dissimilar purpose and use. In this work, we developed a modified algorithm for optimal coalescing that helps a register allocator for an embedded processor to better handle such heterogeneity of the register architecture. In the experiment, an existing register allocator was able to achieve up to 10% reduction in code size through our coalescing, and avoid many spills that would have been generated without our scheme.","Title: Register coalescing techniques for heterogeneous register architecture with copy sifting\nYear: 2009\n\nAbstract: Optimistic coalescing has been proven as an elegant and effective technique that provides better chances of safely coloring more registers in register allocation than other coalescing techniques. Its algorithm originally assumes homogeneous registers, which are all gathered in the same register file. Although this register architecture is still common in most general-purpose processors, embedded processors often contain heterogeneous registers, which are scattered in physically different register files dedicated for each dissimilar purpose and use. In this work, we show that optimistic coalescing is also useful for an embedded processor to better handle such heterogeneity of the register architecture, and developed a modified algorithm for optimal coalescing that helps a register allocator. In the experiment, an existing register allocator was able to achieve up to 13.0% reduction in code size through our coalescing, and avoid many spills that would have been generated without our scheme.","Title: Improving performance of nested loops on reconfigurable array processors\nYear: 2012\n\nAbstract: Pipelining algorithms are typically concerned with improving only the steady-state performance, or the kernel time. The pipeline setup time happens only once and therefore can be negligible compared to the kernel time. However, for Coarse-Grained Reconfigurable Architectures (CGRAs) used as a coprocessor to a main processor, pipeline setup can take much longer due to the communication delay between the two processors, and can become significant if it is repeated in an outer loop of a loop nest. In this paper we evaluate the overhead of such non-kernel execution times when mapping nested loops for CGRAs, and propose a novel architecture-compiler cooperative scheme to reduce the overhead, while also minimizing the number of extra configurations required. Our experimental results using loops from multimedia and scientific domains demonstrate that our proposed techniques can greatly increase the performance of nested loops by up to 2.87 times compared to the conventional approach of accelerating only the innermost loops. Moreover, the mappings generated by our techniques require only a modest number of configurations that can fit in recent reconfigurable architectures.","Title: Management environment of mass windows servers for server-based computing\nYear: 2009\n\nAbstract: Windows Servers for sever-based computing are usually organized with many servers, regardless of the applications. Because more server systems require higher management cost, powerful and easily usable tools are mandatory to manage massive numbers of Windows Servers. In this paper, we present a very flexible management environment that is able to organize and manage massive numbers of Windows Servers. Our management environment is not only flexible in managing Windows Servers with various type of applications but also very powerful so that it can manage more than a thousand of Windows Servers.","Title: A proof method for the correctness of modularized 0CFA\nYear: 2002\n\nAbstract: This article is about our Þndings when we tried to derive a modular version from a whole-program control-ßow analysis (CFA). Deriving a modular version from a whole-program kCFA makes the resulting analysis polyvariant at module- level. Hence the correctness of its modularized version cannot be proven in general with respect to the original kCFA. A convenient stepping-stone to prove the cor- rectness of a modularized version is a whole-program kCFA that is polyvariant at module-level. Because CFA is a basis of almost all analyses for higher-order programs, our result can be seen as a general hint of using the module-variant whole-program analysis in order to ease the correctness proof for a modularized version. Our work can also be seen as a formal investigation, for CFA, of the folklore that modularization improves the analysis accuracy.","Title: Communication studies of single-threaded and multithreaded distributed-memory machines\nYear: 1999\n\nAbstract: This report explicates the communication overlapping capabilities of three distributed-memory machines, SGI/Cray T3E, IBM SP-2 with wide nodes, and the ETL EM-X. Bitonic sorting and Fast Fourier Transform are selected for experiments. Various message sizes are used to determine when, where, how much and why the overlapping takes place. Experimental results with up to 64 processors indicated that the communication performance of EM-X is insensitive to various message sizes while SP-2 is the most sensitive. T3E stayed in between. The EM-X gave the highest communication overlapping capability while T3E did the lowest. The experimental results are compared with the analytical results based on LogP and LogGP communication models","Title: A Comparative Analysis of Dependence Testing Mechanisms\nYear: 2000\n\nAbstract: The internal mechanism used for a dependence test constrains its accuracy and determines its speed. So does the form in which it represents array subscript expressions. The internal mechanism and representational form used for our Access Region Test (ART) is different from that used in any other dependence test, and therefore its constraints and characteristics are likewise different. In this paper, we briefly describe our descriptor for representing memory accesses, the Linear Memory Access Descriptor (LMAD) and the ART. We then describe the LMAD intersection algorithm in some detail. Finally, we compare and contrast the mechanisms of the LMAD intersection algorithm with the internal mechanisms for a number of prior dependence tests.","Title: Compiler transformations for effectively exploiting a zero overhead loop buffer\nYear: 2005\n\nAbstract: A Zero Overhead Loop Buffer (ZOLB) is an architectural feature that is commonly found in DSP processors. This buffer can be viewed as a compiler managed cache that contains a sequence of instructions that will be executed a specified number of times without incurring any loop overhead. Unlike loop unrolling, a loop buffer can be used to minimize loop overhead without the penalty of increasing code size. In addition, a ZOLB requires relatively little space and power, which are both important considerations for most DSP applications. This paper describes strategies for generating code to effectively use a ZOLB. We have found that many common code improving transformations used by optimizing compiler on conventional architectures can be easily used to (1) allow more loops to be placed in a ZOLB, (2) further reduce loop overhead of the loops placed in a ZOLB, and (3) avoid redundant loading of ZOLB loops. The results given in this paper demonstrate that this architectural feature can often be exploited with substantial improvements in execution time and slight reductions in code size for various signal processing applications.","Title: Code optimizations for a VLIW-style network processing unit\nYear: 2004\n\nAbstract: The explosive growth in network bandwidth and Internet services such as QoS (quality of service) and SLA (service level agreement) monitoring have created the need for new networking hardware called a Network Processing Unit (NPU). In order to rapidly reconfigure the NPU for frequently varying Internet services and technologies, a high-performance C compiler is urgently needed. Several code generation techniques, which are intended to meet the high code quality demands of other types of application specific instructionset processors (ASIPs) like digital signal processors (DSPs), have already been developed. However, these techniques are insufficient for NPUs due to striking architectural differences such as asymmetric data paths. The main purpose of this paper is to discuss our recent experience with the development of a commercial compiler for a new NPU called the Paion PPII, which is basically a packet engine for NPU to meet the growing need for new high-bandwidth communication equipment targeted for Internet routers and ethernet adapters. For this purpose, we will first show the architectural challenges posed by the target NPU. Then, we will describe several compiler techniques that we found to be effective for the target NPU with various unorthogonal architectural features. The current implementations of the PPII use a VLIW (Very Long Instruction Word) architecture. So, we handled this VLIW-style architecture by employing a simple code compaction scheme which packs multiple parallel instructions into one long instruction word. The experimental results show that our techniques are effective for significantly reducing the dynamic instruction count.","Title: Dynamic Operands Insertion for VLIW Architecture with a Reduced Bit-width Instruction Set\nYear: 2012\n\nAbstract: Performance, code size and power consumption are all primary concern in embedded systems. To this effect, VLIW architecture has proven to be useful for embedded applications with abundant instruction level parallelism. But due to the long instruction bus width it often consumes more power and memory space than necessary. One way to lessen this problem is to adopt a reduced bit-width instruction set architecture (ISA) that has a narrower instruction word length. This facilitates a more efficient hardware implementation in terms of area and power by decreasing bus-bandwidth requirements and the power dissipation associated with instruction fetches. Also earlier studies reported that it helps to reduce the code size considerably. In practice, however, it is impossible to convert a given ISA fully into an equivalent reduced bit-width one because the narrow instruction word, due to bit-width restrictions, can encode only a small subset of normal instructions in the original ISA. Consequently, existing processors provide narrow instructions in very limited cases along with severe restrictions on register accessibility. The objective of this work is to explore the possibility of complete conversion, as a case study, of an existing 32-bit VLIW ISA into a 16-bit one that supports effectively all 32-bit instructions. To this objective, we attempt to circumvent the bit-width restrictions by dynamically extending the effective instruction word length of the converted 16-bit operations. At compile time when a 32-bit operation is converted to a 16-bit word format, we compute how many bits are additionally needed to represent the whole 32-bit operation and store the bits separately in the VLIW code. Then at run time, these bits are retrieved on demand and inserted to a proper 16-bit operation to reconstruct the original 32-bit representation. According to our experiment, the code size becomes significantly smaller after the conversion to 16-bit VLIW code. Also at a slight run tim- cost, the machine with the 16-bit ISA consumes much less energy than the original machine.","Title: A New Addressing Mode For The Encoding Space Problem On Embedded Processors\nYear: 2009\n\nAbstract: The complexity of today's applications increases with various requirements such as execution time, code size or power consumption. To satisfy these requirements for performance, efficient instruction set design is one of the important issues because an instruction customized for specific applications can make better performance than multiple instructions in aspect of fast execution time, decrease of code size, and low power consumption. Limited encoding space, however, does not allow adding application-specific and complex instructions freely to our instruction set architecture. To resolve this problem, conventional architectures increases free space for encoding by trimming excessive bits required beyond the fixed word length. This approach however shows weakness in terms of the complexity of compiler, code size and execution time. In this paper, we propose a new instruction encoding scheme based on the dynamic implied addressing mode (DIAM) to resolve limited encoding space and side-effect by trimming. Our DIAM-based approach uses a special program memory to store extra encoding information. We also suggest a code generation algorithm to fully utilize the DIAM. In our experiment, the architecture augmented with DIAMs shows about 10% code size reduction and speed up on average, as compared to the base architecture without DIAMs.","Title: KI-Mon: a hardware-assisted event-triggered monitoring platform for mutable kernel object\nYear: 2013\n\nAbstract: Kernel rootkits undermine the integrity of system by manipulating its operating system kernel. External hardware-based monitors can serve as a root of trust that is resilient to rootkit attacks. The existing external hardware-based approaches lack an event-triggered verification scheme for mutable kernel objects. To address the issue, we present KI-Mon, a hardware-based platform for event-triggered kernel integrity monitor. A refined form of bus traffic monitoring efficiently verifies the update values of the objects, and callback verification routines can be programmed and executed for a designated event space. We have built a KI-Mon prototype to demonstrate the efficacy of KI-Mon's event-triggered mechanism in terms of performance overhead for the monitored host system and the processor usage of the KI-Mon processor.","Title: Implementing dynamic implied addressing mode for multi-output instructions\nYear: 2010\n\nAbstract: The ever-increasing demand for faster execution time, smaller resource usage and lower energy consumption has compelled architects of embedded processors to adopt more specialized hardware features with irregular data paths and heterogeneous registers that are customized to the needs of their target applications. These processors consequently provide a rich set of specialized instructions in order to enable programmers to access these features. Such an instruction is typically a multi-output instruction (MOI), which outputs multiple results parallely in order to exploit inherent underlying hardware parallelism. Earlier study has exhibited that MOIs help to enhance performance in aspect of instruction counts and code size. However, as MOIs require more operands, they tend to increase not only the size of the instruction set but also the size of individual instructions. This can be a serious setback for embedded processors, which are mostly subject to strong resource limitations (particularly in this case, limited instruction encoding space). For this reason, these processors are often allowed to include only a very small subset of the total desired MOIs in their instruction sets, despite there can be sufficient silicon real estate to accommodate these specialized MOIs. To attack this problem, we introduce a novel instruction encoding scheme based on the dynamic implied addressing mode (DIAM). In this paper, we will discuss how we have overcome the encoding space problem for our target embedded processor whose instruction set has been augmented with a variety of MOIs. Our DIAM-based encoding scheme employs a small on-chip buffer to supplement extra encoding information for MOIs at run time. The empirical results are promising: the scheme allows us to encode many more MOIs for our processor; thereby helping us to achieve considerable reduction of code size as well as running time after the DIAM is additively implemented in the original architecture.","Title: Bypass aware instruction scheduling for register file power reduction\nYear: 2006\n\nAbstract: Since register files suffer from some of the highest power densities within processors, designers have investigated several architectural strategies for register file power reduction, including \"On Demand RF Read\" where the register file is read only if the operand value is not available from the bypasses. However, we show in this paper that significant additional reductions in the register file power consumption can be obtained by scheduling instructions so that they transfer the operands via bypasses, rather than reading from the register file. Such instruction scheduling requires the compiler to be cognizant of the bypasses in the processor pipeline. In this paper, we develop several bypass aware instruction scheduling heuristics varying in time complexity, and study their effectiveness on the Intel XScale processor pipeline running MiBench benchmarks. Our experimental results show additional power consumption reductions of up to 26% and on average 12% over and above the register file power reduction achieved through existing techniques.","Title: Efficient and precise array access analysis\nYear: 2002\n\nAbstract: A number of existing compiler techniques hinge on the analysis of array accesses in a program. The most important task in array access analysis is to collect the information about array accesses of interest and summarize it in some standard form. Traditional forms used in array access analysis are sensitive to the complexity of array subscripts; that is, they are usually quite accurate and efficient for simple array subscripting expressions, but lose accuracy or require potentially expensive algorithms for complex subscripts. Our study has revealed that in many programs, particularly numerical applications, many access patterns are simple in nature even when the subscripting expressions are complex. Based on this analysis, we have developed a new, general array region representational form, called the linear memory access descriptor (LMAD). The key idea of the LMAD is to relate all memory accesses to the linear machine memory rather than to the shape of the logical data structures of a programming language. This form helps us expose the simplicity of the actual patterns of array accesses in memory, which may be hidden by complex array subscript expressions. Our recent experimental studies show that our new representation simplifies array access analysis and, thus, enables efficient and accurate compiler analysis.","Title: A code-generator generator for multi-output instructions\nYear: 2007\n\nAbstract: We address the problem of instruction selection for Multi-Output Instructions (MOIs), producing more than one result. Such inherently parallel hardware instructions are very common in the area of Application Specific Instruction Set Processors (ASIPs) and Digital Signal Processors (DSPs) which are frequently used in System-on-Chips as programmable cores. In order to provide high-level programmability, and consequently guarantee widespread acceptance, sophisticated compiler support for these programmable cores is of high importance. Since it is not possible to model Multi-Output Instructions as trees in the compiler's Intermediate Representation (IR), traditional approaches for code selection are not sufficient. Extending traditional code-generation approaches for MOI-selection is essentially a graph covering problem, which is known to be NP-complete. We present a new heuristic algorithm incorporated in a retargetable code-generator generator capable of exploiting arbitrary inherently parallel MOIs. We prove the concept by integrating the tool into the LCC compiler which has been targeted towards different Instruction Set Architectures based on the MIPS architecture. Several network applications as well as some DSP benchmarks were compiled and evaluated to obtain results.","Title: Orthogonal Instruction Encoding for a 16-bit Embedded Processor with Dynamic Implied Addressing Mode\nYear: 2009\n\nAbstract: Although 32-bit architectures are becoming the norm for modern microprocessors, 16-bit ones are still employed by many low-end processors, for which small size and low power consumption are of high priority. However, 16-bit architectures have a critical disadvantage for embedded processors that they do not provide enough encoding space to add special instructions coined for certain applications. To overcome this, many existing architectures adopt non-orthogonal, irregular instruction sets to accommodate a variety of unusual addressing modes thru which more opcodes and operands are densely encoded within the narrow instruction word. In general, these non-orthogonal architectures are regarded compiler-unfriendly as they tend to requires extremely sophisticated compiler techniques for optimal code generation. To address this issue, we propose a compiler-friendly processor with a new addressing mode, called the dynamic implied addressing mode (DIAM). In this paper, we will demonstrate that the DIAM provides more encoding space for our 16-bit processor so that we are able to support more instructions specially customized for our applications. And yet, the processor maintains a RISC-style orthogonal architecture, thereby allowing us to use traditional code generation algorithms. In our experiment, the architecture augmented with DIAMs shows 6.2% code size reduction and 3.5% performance increase on average, as compared to the basic architecture without DIAMs.","Title: A Quantitative Comparison of Two Retargetable Compilation Approaches.\nYear: 2003\n\nAbstract: In the design of an embedded processor, the compiler design is tightly coupled with the underlying processor architecture, and thus it is crucial to rapidly retarget a compiler along with the change in the architecture in order to expedite the processor design. However, among many compiler writers, there is a controversial issue that has long been argued - whether a compiler can be easily retargetable while it performs sophisticated machine-specific optimizations for a new architecture configuration. This study examines this issue by finding some possible cases where optimizations may be impeded on a pathway to building a retargetable compiler For this, we developed two types of compilation frameworks called user-retargetable and developer-retargetable, and compared their performance.","Title: Compiler and microarchitectural approaches for register file thermal management\nYear: 2012\n\nAbstract: Register files are responsible for the majority of thermal emergencies in high performance processors. In this paper, we propose compiler-microarchitecture cooperative techniques to reduce the performance penalty incurred by existing thermal management schemes. Our experiments show that an existing dynamic thermal management (DTM) scheme may result in 47% performance degradation at 45 nm technology node as compared to the ideal case where the processor can sustain any thermal emergency and no DTM is applied. We also evaluate performance degradation of a couple of other DTMs and demonstrate that our cooperative policy can bring down this performance penalty. Our approach shows the consistent effectiveness even with the technology scaling.","Title: Fast memory bank assignment for fixed-point digital signal processors\nYear: 2004\n\nAbstract: Most vendors of digital signal processors (DSPs) support a Harvard architecture, which has two or more memory buses, one for program and one or more for data and allow the processor to access multiple words of data from memory in a single instruction cycle. Also, many existing fixed-point DSPs are known to have an irregular architecture with heterogeneous registers, which contains multiple register files that are distributed and dedicated to different sets of instructions. Although there have been several studies conducted to efficiently assign data to multimemory banks, most of them assumed processors with relatively simple, homogeneous general-purpose registers. Thus, several vendor-provided compilers for DSPs that we examined were unable to efficiently assign data to multiple data memory banks, thereby often failing to generate highly optimized code for their machines. As a consequence, programmers for these DSPs often manually assign program variables to memories so as to fully utilize multimemory banks in their code. This paper reports on our recent attempt to address this problem by presenting an algorithm that helps the compiler to efficiently assign data to multimemory banks. Our algorithm differs from previous work in that it assigns variables to memory banks in separate, decoupled code generation phases, instead of a single, tightly coupled phase. The experimental results have revealed that our decoupled algorithm greatly simplifies our code generation process; thus our compiler runs extremely fast, yet generates target code that is comparable in quality to the code generated by a coupled approach.","Title: Dynamic code duplication with vulnerability awareness for soft error detection on VLIW architectures\nYear: 2013\n\nAbstract: Soft errors are becoming a critical concern in embedded system designs. Code duplication techniques have been proposed to increase the reliability in multi-issue embedded systems such as VLIW by exploiting empty slots for duplicated instructions. However, they increase code size, another important concern, and ignore vulnerability differences in instructions, causing unnecessary or inefficient protection when selecting instructions to be duplicated under constraints. In this article, we propose a compiler-assisted dynamic code duplication method to minimize the code size overhead, and present vulnerability-aware duplication algorithms to maximize the effectiveness of instruction duplication with least overheads for VLIW architecture. Our experimental results with SoarGen and Synopsys simulation environments demonstrate that our proposals can reduce the code size by up to 40% and detect more soft errors by up to 82% via fault injection experiments over benchmarks from DSPstone and Livermore Loops as compared to the previously proposed instruction duplication technique.","Title: Extrax: security extension to extract cache resident information for snoop-based external monitors\nYear: 2015\n\nAbstract: Advent of rootkits has urged researchers to conduct much research on defending the integrity of OS kernels. Even though recently proposed snoop-based monitors have shown to provide higher performance and security level compared to conventional hypervisor-based monitors, we discovered that the use of write-back caches in a system would seriously undermine the effectiveness of snoop-based monitors. To address the problem, we propose a special hardware unit called Extrax which makes use of existing hardware logic, core debugging interface, to extract necessary information for security monitoring. Being implemented to refine the debug information for security purposes, Extrax assists snoop-based monitors to detect attacks that exploit write-back caches. Experimental results show that our system can detect more advanced attacks, which the state-of-the-art snoop-based hardware monitors cannot capture, with moderate area overhead and power consumption.","Title: Techniques to Minimize State Transfer Costs for Dynamic Execution Offloading in Mobile Cloud Computing\nYear: 2014\n\nAbstract: In order to meet the increasing demand for high performance in smartphones, recent studies suggested mobile cloud computing techniques that aim to connect the phones to adjacent powerful cloud servers to throw their computational burden to the servers. These techniques often employ execution offloading schemes that migrate a process between machines during its execution. In execution offloading, code regions to be executed on the server are decided statically or dynamically based on the complex analysis on execution time and process state transfer costs of every region. Expectedly, the transfer cost is a deciding factor for the success of execution offloading. According to our analysis, it is dominated by the total size of heap objects transferred over the network. But previous work did not try hard to minimize this size. Thus in this paper, we introduce novel techniques based on compiler code analysis that effectively reduce the transferred data size by transferring only the essential heap objects and the stack frames actually referenced in the server. The experiments exhibit that the reduced size positively influences not only the transfer time itself but also the overall effectiveness of execution offloading, and ultimately, improves the performance of our mobile cloud computing significantly in terms of execution time and energy consumption.","Title: CMcloud: Cloud Platform for Cost-Effective Offloading of Mobile Applications\nYear: 2014\n\nAbstract: Recent efforts towards mobile cloud propose to offload mobile applications to cloud servers for the improved performance and battery life of mobile devices. However, existing schemes completely ignore the costs of cloud resources by assuming that idle servers are always available for free of charge. These unrealistic assumptions make each server run only a small load to achieve the guaranteed high offload performance. Therefore, these schemes cannot be applied to real-world commercial clouds which aim to minimize the operation costs by maximizing the server throughput, and then charge users for their resource usage. In this paper, we propose CMcloud, a novel cost-effective mobile-to-cloud offloading platform, which works nicely under the real-world cloud environments. CMcloud minimizes both the server costs and the user service fee by offloading as many mobile applications to a single server as possible, while satisfying the target performance of all applications. To achieve such goals, CMcloud exploits novel architecture performance modeling and server migration techniques. Our implementation shows that CMcloud can improve the data enter throughput by 84% over a conventional static light-load scheme (or a 2.7x higher per-socket throughput.) Alternatively, CMcloud reduces the number of service failures by 83% over a static high-load scheme, while even improving the throughput by 31%.","Title: Software-Based Selective Validation Techniques for Robust CGRAs Against Soft Errors.\nYear: 2016\n\nAbstract: Coarse-Grained Reconfigurable Architectures (CGRAs) are drawing significant attention since they promise both performances with parallelism and flexibility with reconfiguration. Soft errors (or transient faults) are becoming a serious design concern in embedded systems including CGRAs since the soft error rate is increasing exponentially as technology is scaling. A recently proposed software-based technique with TMR (Triple Modular Redundancy) implemented on CGRAs incurs extreme overheads in terms of runtime and energy consumption mainly due to expensive voting mechanisms for the outputs from the triplication of every operation. In this article, we propose selective validation mechanisms for efficient modular redundancy techniques in the datapaths on CGRAs. Our techniques selectively validate the results at synchronous operations rather than every operation in order to reduce the expensive performance overhead from the validation mechanism. We also present an optimization technique to further improve the runtime and the energy consumption by minimizing synchronous operations where a validating mechanism needs to be applied. Our experimental results demonstrate that our selective validation-based TMR technique with our optimization on CGRAs can improve the runtime by 41.0p and the energy consumption by 26.2p on average over benchmarks as compared to the recently proposed software-based TMR technique with the full validation.","Title: Implementing an Application-Specific Instruction-Set Processor for System-Level Dynamic Program Analysis Engines\nYear: 2015\n\nAbstract: In recent years, dynamic program analysis (DPA) has been widely used in various fields such as profiling, finding bugs, and security. However, existing solutions have their own weaknesses. Software solutions provide flexibility in DPA but they suffer from tremendous performance overhead. In contrast, core-level hardware engines rely on specialized integrated logics and attain extremely fast computation, but they have a limited functional extensibility because the logics are tightly coupled with the host processor. To mend this, a prior system-level approach utilizes an existing channel to integrate their hardware without necessitating the host architecture modification and introduced great potential in performance. Nevertheless, the prior work does not address the detailed design and implementation of the engine, which is quite essential to leverage the deployment on real systems. To address this, in this article, we propose an implementation of programmable DPA hardware engine, called program analysis unit (PAU). PAU is an application-specific instruction-set processor (ASIP) whose instruction set is customized to reflect common features of various DPA methods. With the specialized architecture and programmability of software, our PAU aims at fast computation and sufficient flexibility. In our case studies on several DPA techniques, we show that our ASIP approach can be successfully applicable to complex DPA schemes while providing hardware-backed power in performance and software-based flexibility in analysis. Recent experiments on our FPGA prototype revealed that the performance of PAU is 4.7-13.6 times faster than pure software DPA, and the power/area consumption is also acceptably small compared to today's mobile processors.","Title: Efficient dynamic information flow tracking on a processor with core debug interface\nYear: 2015\n\nAbstract: Dynamic information flow tracking (DIFT) is a promising solution to prevent various attacks on software running on a processor. Previous hardware solutions usually mandate drastic change to internal processor architecture. More recent ones to minimize the change have proposed external devices for DIFT. However, these approaches intrinsically suffer from the high overhead to communicate with their external devices. Consequently, they either significantly lose performance, or inevitably make invasive modifications to the processor inside. Our solution also rely on external hardware for DIFT, but unlike theirs, ours exploits the core debug interface (CDI) to tackle the communication issue. CDI is provided in most commercial processors for debugging so that we were able to build our system simply by plugging our hardware to the processor via CDI, precluding the need for altering the processor itself. Experiments show that our hardware efficiently performs DIFT mainly thanks to the support of CDI that helps us cut substantially down the communication costs.","Title: Accelerating bootstrapping in FHEW using GPUs\nYear: 2015\n\nAbstract: Recently, the usage of GPU is not limited to the jobs associated with graphics and a wide variety of applications take advantage of the flexibility of GPUs to accelerate the computing performance. Among them, one of the most emerging applications is the fully homomorphic encryption (FHE) scheme, which enables arbitrary computations on encrypted data. Despite much research effort, it cannot be considered as practical due to the enormous amount of computations, especially in the bootstrapping procedure. In this paper, we accelerate the performance of the recently suggested fast bootstrapping method in FHEW scheme using GPUs, as a case study of a FHE scheme. In order to optimize, we explored the reference code and carried out profiling to find out candidates for performance acceleration. Based on the profiling results, combined with more flexible tradeoff method, we optimized the bootstrapping algorithm in FHEW using GPU and CUDA's programming model. The empirical result shows that the bootstrapping of FHEW ciphertext can be done in less than 0.11 second after optimization.","Title: Towards a practical solution to detect code reuse attacks on ARM mobile devices\nYear: 2015\n\nAbstract: In recent years, there is a growing need to protect security and privacy of the data against various attacks on software running on smart mobile devices. The attackers mostly attempt to acquire privileges to control system behaviors as they want. As of today, the code reuse attack (CRA) is known as one of the most sophisticated techniques that can be exploited in such attempts. The attackers launch CRAs to perform arbitrary computation by reusing and chaining existing code fragments, called gadgets. Prior solutions to CRAs are engineered either in software or hardware. However, both of them have their own weaknesses. Software solutions suffer from huge performance overhead because they occupy computing resources of the host CPU. On the other hand, existing hardware solutions all require invasive modifications to the CPU internal architecture. This is contradictory to the conventional application processor (AP) design principle which is to integrate off-the-shelf commodity CPU cores and other special-purpose hardware modules together to form a system. In this paper, we propose a more practical hardware solution which conforms to such design convention, thus being amenable for immediate deployment to modern mobile devices that use APs as their central computing engines. In our work, we target the devices that employ as their AP CPUs the ARM processors which are the de-facto standard CPUs for commercial mobile devices today. The key difference of ours from previous hardware solutions is that our CRA detection hardware modules have been integrated as off-core modules with the processor, strictly following the AP designing principle. We exploit the ARM debug interface to obtain the core internal information which is not directly accessible from off-core hardware modules. As a result, we were able to detect CRAs from outside the CPU without modifying the processor internal. For our preliminary experiment, we have implemented in our prototype a module to detect the attacks based on return-oriented programming (ROP) which is a representative technique used in CRAs. Empirical results show that our solution successfully detects ROP attacks with negligibly low runtime overhead and moderate area overhead.","Title: Energy-Reduction Offloading Technique for Streaming Media Servers.\nYear: 2016\n\nAbstract: Recent growth in popularity of mobile video services raises a demand for one of the most popular and convenient methods of delivering multimedia data, video streaming. However, heterogeneity of currently existing mobile devices involves an issue of separate video transcoding for each type of mobile devices such as smartphones, tablet PCs, and smart TVs. As a result additional burden comes to media servers, which pretranscode multimedia data for number of clients. Regarding even higher increase of video data in the Internet in the future, the problem of media servers overload is impending. To struggle against the problem an offloading method is introduced in this paper. By the use of SorTube offloading framework video transcoding process is shifted from the centralized media server to the local offloading server. Thus, clients can receive personally customized video stream; meanwhile the overload of centralized servers is reduced.","Title: Architectural Supports to Protect OS Kernels from Code-Injection Attacks.\nYear: 2016\n\nAbstract: The kernel code injection is a common behavior of kernel -compromising attacks where the attackers aim to gain their goals by manipulating an OS kernel. Several security mechanisms have been proposed to mitigate such threats, but they all suffer from non-negligible performance overhead. This paper introduces a hardware reference monitor, called Kargos, which can detect the kernel code injection attacks with nearly zero performance cost. Kargos monitors the behaviors of an OS kernel from outside the CPU through the standard bus interconnect and debug interface available with most major microprocessors. By watching the execution traces and memory access events in the monitored target system, Kargos uncovers attempts to execute malicious code with the kernel privilege. According to our experiments, Kargos detected all the kernel code injection attacks that we tested, yet just increasing the computational loads on the target CPU by less than 1% on average.","Title: Hardware-Assisted On-Demand Hypervisor Activation for Efficient Security Critical Code Execution on Mobile Devices.\nYear: 2016\n\nAbstract: As more and more mobile applications need to run security critical codes (SCCs) for secure transactions and critical information handling, the demand for a Trusted Execution Environment (TEE) to ensure safe execution of SCCs is rapidly escalating. Although a number of studies have implemented TEEs using TrustZone or hypervisors and have evinced the effectiveness in terms of security, they face major challenges when considering deployment in mobile devices. TrustZone-based approaches bloat the TCB of the system as they must increase the code base size of the most privileged software. Hypervisor-based approaches incur performance overhead on mobile devices that are already suffering from resource restrictions. To alleviate these problems, in this paper, we propose a hybrid approach that utilizes both TrustZone and a hypervisor. Our approach basically implements a TEE using a hypervisor, while mitigating performance overhead by activating the hypervisor only when the TEE is demanded by SCCs. This scheme, called on-demand hypervisor activation, has been efficiently and securely implemented by leveraging the memory protection capability of TrustZone. We have implemented and experimented our system with real world applications. The results show that our system can successfully protect SCCs without any noticeable delay (< 100 µs), while limiting the overhead increase due to our hypervisor during its hibernation near 0 %.","Title: HDFI: Hardware-Assisted Data-Flow Isolation\nYear: 2016\n\nAbstract: Memory corruption vulnerabilities are the root cause of many modern attacks. Existing defense mechanisms are inadequate; in general, the software-based approaches are not efficient and the hardware-based approaches are not flexible. In this paper, we present hardware-assisted data-flow isolation, or, HDFI, a new fine-grained data isolation mechanism that is broadly applicable and very efficient. HDFI enforces isolation at the machine word granularity by virtually extending each memory unit with an additional tag that is defined by dataflow. This capability allows HDFI to enforce a variety of security models such as the Biba Integrity Model and the Bell -- LaPadula Model. We implemented HDFI by extending the RISC-V instruction set architecture (ISA) and instantiating it on the Xilinx Zynq ZC706 evaluation board. We ran several benchmarks including the SPEC CINT 2000 benchmark suite. Evaluation results show that the performance overhead caused by our modification to the hardware is low (<; 2%). We also developed or ported several security mechanisms to leverage HDFI, including stack protection, standard library enhancement, virtual function table protection, code pointer protection, kernel data protection, and information leak prevention. Our results show that HDFI is easy to use, imposes low performance overhead, and allows us to create more elegant and more secure solutions.","Title: Integration of ROP/JOP monitoring IPs in an ARM-based SoC\nYear: 2016\n\nAbstract: Code reuse attack (CRA) is a powerful technique that allows attackers to perform arbitrary computation by reusing the existing code fragments. To defend from CRAs while complying with the conventional ARM-based SoC design principles, the previous hardware solution suggests the use of the ARM debug interface to acquire the control flow information of an application running on the host. However, it requires tremendous storage space to store the complementary data necessary to trace the execution flow. In this paper, we propose a new hardware CRA monitor which gives both low storage overhead and high performance. For this, we have used an instrumentation technique which transforms the original ARM binary code into a form which will ease the CRA monitor to efficiently extract through the debug interface all crucial pieces of runtime information from the trace outcomes. In addition, while the previous solution was only built to detect one type of CRAs, called return-oriented programming (ROP), ours has been designed to unify the detection logics for ROP and another important type of CRAs, called jump-oriented programming (JOP). Empirical results show that our solution dramatically reduces the storage overhead for CRA detection, yet successfully detecting both ROP and JOP attacks simultaneously with negligibly low runtime overhead and moderate area overhead.","Title: A hardware-based technique for efficient implicit information flow tracking.\nYear: 2016\n\nAbstract: To access sensitive information, some recent advanced attacks have been successful in exploiting implicit flows in a program in which sensitive data affects the control path and in turn affects other data. To track the sensitive data through implicit flows, several software and hardware based approaches have been proposed, but they suffer from the non-negligible performance overhead. In this paper, we propose a hardware tracking engine for implicit flow, called the implicit flow tracking unit (IFTU). By adopting the tracking scheme for implicit flow and mapping it to the specialized hardware, our solution can efficiently perform the implicit flow tracking with reasonable area costs.","Title: LSTM-Based System-Call Language Modeling and Robust Ensemble Method for Designing Host-Based Intrusion Detection Systems.\nYear: 2016\n\nAbstract: In computer security, designing a robust intrusion detection system is one of the most fundamental and important problems. In this paper, we propose a system-call language-modeling approach for designing anomaly-based host intrusion detection systems. To remedy the issue of high false-alarm rates commonly arising in conventional methods, we employ a novel ensemble method that blends multiple thresholding classifiers into a single one, making it possible to accumulate u0027highly normalu0027 sequences. The proposed system-call language model has various advantages leveraged by the fact that it can learn the semantic meaning and interactions of each system call that existing methods cannot effectively consider. Through diverse experiments on public benchmark datasets, we demonstrate the validity and effectiveness of the proposed method. Moreover, we show that our model possesses high portability, which is one of the key aspects of realizing successful intrusion detection systems.","Title: Efficient Security Monitoring with the Core Debug Interface in an Embedded Processor.\nYear: 2016\n\nAbstract: For decades, various concepts in security monitoring have been proposed. In principle, they all in common in regard to the monitoring of the execution behavior of a program (e.g., control-flow or dataflow) running on the machine to find symptoms of attacks. Among the proposed monitoring schemes, software-based ones are known for their adaptability on the commercial products, but there have been concerns that they may suffer from nonnegligible runtime overhead. On the other hand, hardware-based solutions are recognized for their high performance. However, most of them have an inherent problem in that they usually mandate drastic changes to the internal processor architecture. More recent ones have strived to minimize such modifications by employing external hardware security monitors in the system. However, these approaches intrinsically suffer from the overhead caused by communication between the host and the external monitor. Our solution also relies on external hardware for security monitoring, but unlike the others, ours tackles the communication overhead by using the core debug interface (CDI), which is readily available in most commercial processors for debugging. We build our system simply by plugging our monitoring hardware into the processor via CDI, precluding the need for altering the processor internals. To validate the effectiveness of our approach, we implement two well-known monitoring techniques on our proposed framework: dynamic information flow tracking and branch regulation. The experimental results on our FPGA prototype show that our external hardware monitors efficiently perform monitoring tasks with negligible performance overhead, mainly with thanks to the support of CDI, which helps us reduce communication costs substantially.","Title: Optimization techniques to enable execution offloading for 3D video games.\nYear: 2017\n\nAbstract: Nowadays, mobile devices are becoming the most popular computing device as their computing capabilities increase rapidly. However, it is still challenging to execute highly sophisticated applications such as 3D video games on mobile devices due to its constrained key computational resources. Execution offloading approaches have been proposed to resolve this problem by strengthening mobile devices with powerful cloud. Unfortunately, the existing offloading approaches are not suitable for 3D video games because of the unique execution characteristics of them. In this paper, we propose a streaming-based execution offloading framework to enable execution offloading for 3D video games. The experiments show that our framework successfully guarantees 20 frames per second for our benchmark.","Title: Using CoreSight PTM to Integrate CRA Monitoring IPs in an ARM-Based SoC.\nYear: 2017\n\nAbstract: The ARM CoreSight Program Trace Macrocell (PTM) has been widely deployed in recent ARM processors for real-time debugging and tracing of software. Using PTM, the external debugger can extract execution behaviors of applications running on an ARM processor. Recently, some researchers have been using this feature for other purposes, such as fault-tolerant computation and security monitoring. This motivated us to develop an external security monitor that can detect control hijacking attacks, of which the goal is to maliciously manipulate the control flow of victim applications at an attacker’s disposal. This article focuses on detecting a special type of attack called code reuse attacks (CRA), which use a recently introduced technique that allows attackers to perform arbitrary computation without injecting their code by reusing only existing code fragments. Our external monitor is attached to the outside of the host system via the system bus and ARM CoreSight PTM, and is fed with execution traces of a victim application running on the host. As a majority of CRAs violates the normal execution behaviors of a program, our monitor constantly watches and analyzes the execution traces of the victim application and detects a symptom of attacks when the execution behaviors violate certain rules that normal applications are known to adhere. We present two different implementations for this purpose: a hardware-based solution in which all CRA detection components are implemented in hardware, and a hardware/software mixed solution that can be employed in a more resource-constrained environment where the deployment of full hardware-level CRA detection is burdensome.","Title: Instruction-Level Data Isolation for the Kernel on ARM.\nYear: 2017\n\nAbstract: As more sophisticated services are increasingly offered by the OS kernel on mobile devices, the security and sensitivity of kernel data that they depend on are becoming a critical issue. Data isolation has emerged as a key technique that can address the issue by providing strong protection for sensitive kernel data. However, existing data isolation mechanisms for mobile devices all incur non-negligible performance overhead. We deem that such computational burden would be a serious problem for mobile devices which already suffer from resource poverty. To alleviate this problem, we have developed a new mechanism that enforces data isolation very efficiently on ARM-based machines backed by unique hardware instructions. For evaluation, this instruction-level data isolation mechanism has been implemented in the Android/Linux kernel running on ARM. According to the experiment, it provides a lightweight data isolation capability for security services installed in the kernel.","Title: Architectural Supports to Protect OS Kernels from Code-Injection Attacks and Their Applications.\nYear: 2017\n\nAbstract: The kernel code injection is a common behavior of kernel-compromising attacks where the attackers aim to gain their goals by manipulating an OS kernel. Several security mechanisms have been proposed to mitigate such threats, but they all suffer from non-negligible performance overhead. This article introduces a hardware reference monitor, called Kargos, which can detect the kernel code injection attacks with nearly zero performance cost. Kargos monitors the behaviors of an OS kernel from outside the CPU through the standard bus interconnect and debug interface available with most major microprocessors. By watching the execution traces and memory access events in the monitored target system, Kargos uncovers attempts to execute malicious code with the kernel privilege. On top of this, we also applied the architectural supports for Kargos to the detection of ROP attacks. KS-Stack is the hardware component that builds and maintains the shadow stacks using the existing supports to detect this ROP attacks. According to our experiments, Kargos detected all the kernel code injection attacks that we tested, yet just increasing the computational loads on the target CPU by less than 1% on average. The performance overhead of the KS-Stack was also less than 1%.","Title: Extended Abstract: Mimicry Resilient Program Behavior Modeling with LSTM based Branch Models.\nYear: 2018\n\nAbstract: In the software design, protecting a computer system from a plethora of software attacks or malware in the wild has been increasingly important. One branch of research to detect the existence of attacks or malware, there has been much work focused on modeling the runtime behavior of a program. Stemming from the seminal work of Forrest et al., one of the main tools to model program behavior is system call sequences. Unfortunately, however, since mimicry attacks were proposed, program behavior models based solely on system call sequences could no longer ensure the security of systems and require additional information that comes with its own drawbacks. In this paper, we report our preliminary findings in our research to build a mimicry resilient program behavior model that has lesser drawbacks. We employ branch sequences to harden our program behavior model against mimicry attacks while employing hardware features for efficient extraction of such branch information during program runtime. In order to handle the large scale of branch sequences, we also employ LSTM, the de facto standard in deep learning based sequence modeling and report our preliminary experiments on its interaction with program branch sequences.","Title: A dynamic per-context verification of kernel address integrity from external monitors.\nYear: 2018\n\nAbstract: The introduction of Address Translation Redirection Attack (ATRA) has revealed a critical weakness in all existing hardware-based external kernel integrity monitors. The attack redefines system's memory mappings in favor of the attacker so that the monitored kernel regions are relocated out of the monitor's sight. We provide a generalized approach and a prototype evaluation to prove our proposed scheme for ensuring the integrity of kernel address mapping from external monitors.","Title: Design of a Generic Security Interface for RISC-V Processors and its Applications\nYear: 2018\n\nAbstract: In this paper, we propose the design of a generic security interface for RISC-V. This interface increases flexibility of security modules by creating an environment that can operate independently on a host processor. We also present an application using this interface for the memory protection. To check the feasibility of our idea, we implement an early prototype where a RISC-V processor is connected with the proposed hardware components using our interface. The empirical results show that our security interface has enabled a security module operated independently of the processor with no performance and low area overhead.","Title: Safe and Efficient Implementation of a Security System on ARM using Intra-level Privilege Separation\nYear: 2019\n\nAbstract: Security monitoring has long been considered as a fundamental mechanism to mitigate the damage of a security attack. Recently, intra-level security systems have been proposed that can efficiently and securely monitor system software without any involvement of more privileged entity. Unfortunately, there exists no full intra-level security system that can universally operate at any privilege level on ARM. However, as malware and attacks increase against virtually every level of privileged software including an OS, a hypervisor, and even the highest privileged software armored by TrustZone, we have been motivated to develop an intra-level security system, named Hilps. Hilps realizes true intra-level scheme in all these levels of privileged software on ARM by elaborately exploiting a new hardware feature of ARM’s latest 64-bit architecture, called TxSZ, that enables elastic adjustment of the accessible virtual address range. Furthermore, Hilps newly supports the sandbox mechanism that provides security tools with individually isolated execution environments, thereby minimizing security threats from untrusted security tools. We have implemented a prototype of Hilps on a real machine. The experimental results demonstrate that Hilps is quite promising for practical use in real deployments.","Title: KI-Mon ARM: A Hardware-Assisted Event-triggered Monitoring Platform for Mutable Kernel Object\nYear: 2019\n\nAbstract: External hardware-based kernel integrity monitors have been proposed to mitigate kernel-level malwares. However, the existing external approaches have been limited to monitoring the static regions of kernel while the latest rootkits manipulate the dynamic kernel objects. To address the issue, we present KI-Mon, a hardware-based platform that introduces event-triggered monitoring techniques for kernel dynamic objects. KI-Mon advances the bus traffic snooping technique to not only detect memory write traffic on the host bus but also filter out all but meaningful traffic to generate events. We show how kernel invariant verification software can be developed around these events, and also provide a set of APIs for additional invariant verification development. We also report our findings and considerations on the unique challenges for external monitors – such as cache coherency, dynamic object tracing. We introduce host-side kernel changes that alleviate these issues that involve changes in kernel's object allocation and cache policy control. We have built a prototype of KI-Mon on the ARM architecture to demonstrate the efficacy of KI-Mon's event-triggered mechanism in terms of performance overhead for the monitored host system and the processor usage of the KI-Mon processor.","Title: DADE: a fast data anomaly detection engine for kernel integrity monitoring\nYear: 2019\n\nAbstract: In computer systems, ensuring the integrity of the kernel assumes importance as attacks against the kernel allow an adversary to obtain the highest privilege within a compromised system. For this task, typically, an external monitor would perform memory introspection and verify the integrity of kernel data by checking whether certain integrity specifications hold or not. These specifications were commonly written by hand in the past. However, as adversaries turned their eyes to attacking a system through non-control kernel data, the need arose for verifying non-control kernel data, which is, unfortunately, nontrivial to do manually. Acknowledging this, Baliga et al. (Computer security applications conference, 2008. ACSAC 2008. Annual. IEEE, 2008) suggested a framework leveraging machine learning to generate integrity specifications. This generated specifications for both control and non-control data across the entire kernel with little human involvement. Unfortunately, there is a problem in the original design of this framework in regard to its practicality for deployment in real-world systems. In this paper, we propose a new design that accelerates the overall introspection process by virtually eliminating the booting delay that was needed in prior work. To evaluate the effectiveness of our design, we have implemented a prototype engine DADE and found that it only induces a delay of 68.49 ms with each reboot and a delay of 900 ms for an initial scan and an average of 160 ms for subsequent scans.","Title: Developing a custom DSP for vision based human computer interaction applications.\nYear: 2018\n\nAbstract: As the computing power of modern devices become greater, computer vision is increasingly adopted as the means of human-computer interaction. The industry is struggling hard to bring computer vision into the mobile domain, but there are some difficulties mainly due to the computationally expansive nature of vision applications. On the other hand, there are various kinds of vision applications, which means using fixed hardware block will meet the performance criteria, but it will be possible to run only one application. To meet our needs, we can use another programmable component that is specialized for parallel processing and has domain specific instructions. In this paper, we introduce our work on the development of a low-power VLIW processor with vision-application specific parallel computation logic and a set of application-specific instructions, to improve the processor’s performance while reducing the power consumption. Our VLIW processor accelerates by adding special instructions on the application’s specific part in which processes heavy computation. We introduce our work on developing a custom DSP for vision system that includes designing the processor with Synopsys Processor Designer tool, and porting LLVM compiler. As the target, we ported a hand recognition application to our system, which we have constructed on Xilinx Zynq evaluation board. Even though our DSP was run at much lower frequency, it could run compute intensive part of the application four times faster than ARM processor, greatly speeding up the whole application.","Title: Riskim: Toward Complete Kernel Protection With Hardware Support\nYear: 2019\n\nAbstract: The OS kernel is typically the assumed trusted computing base in a system. Consequently, when they try to protect the kernel, developers often build their solutions in a separate secure execution environment externally located and protected by special hardware. Due to limited visibility into the host system, the external solutions basically all entail the semantic gap problem which can be easily exploited by an adversary to circumvent them. Thus, for complete kernel protection against such adversarial exploits, previous solutions resorted to aggressive techniques that usually come with various adverse side effects, such as high performance overhead, kernel code modifications and/or excessively complicated hardware designs. In this paper, we introduce RiskiM, our new hardware-based monitoring platform to ensure kernel integrity from outside the host system. To overcome the semantic gap problem, we have devised a hardware interface architecture, called PEMI, by which RiskiM is supplied with all internal states of the host system essential for fulfilling its monitoring task to protect the kernel even in the presence of attacks exploiting the semantic gap between the host and RiskiM. To empirically validate the security strength and performance of our monitoring platform in existing systems, we have fully implemented RiskiM in a RISCV system. Our experiments show that RiskiM succeeds in the host kernel protection by detecting even the advanced attacks which could circumvent previous solutions, yet suffering from virtually no aforementioned side effects.","Title: Real-Time Anomalous Branch Behavior Inference With A Gpu-Inspired Engine For Machine Learning Models\nYear: 2019\n\nAbstract: Attacks on embedded devices are likely to occur any time in unexpected manners. Thus, the defense systems based on fixed sets of rules will easily be subverted by such unexpected, unknown attacks. Learning-based anomaly detection may potentially prevent new unknown zero-day attacks by leveraging the capability of machine learning (ML) to learn the intricate true nature of software hidden within raw information. This paper introduces our work to develop an MPSoC, called RTAD, which can efficiently support in hardware various ML models that run to detect anomalous behaviors on embedded devices in a real-time fashion, and thus enable the devices to counteract the anomalies in the field. In the IoT era, the importance of security for embedded devices cannot be exaggerated because they will become an enticing target for adversaries as they are being integrated into everyday life to provide users with various services. The above-mentioned potential of learning-based detection is believed to benefit those deployed devices under attacks occurring any time during their field operations in unexpected manners. We hereby assume that ML models are trained with runtime branch information as their data features since a sequence of branches serves as a record of control flow transfers during program execution. In fact, there have been numerous ML studies that examine various types of branches in order to infer (or detect) anomaly in branch behaviors that may be induced by diverse attacks that can cause deviant control flow in software. Our goal of real-time anomalous branch behavior inference poses two challenges to our development of RTAD. Firstly, RTAD must collect and transfer in a timely fashion a sequence of branches as the input to the ML model. Secondly, RTAD must be able to promptly process the delivered branch data with the ML model. To tackle these challenges, we have implemented in RTAD two core components: an input generation module and a GPU-inspired ML processing engine. According to our experiments, RTAD enables various ML models to infer anomaly instantly after the victim program behaves aberrantly as the result of attacks being injected into the system.","Title: Learn2Evade: Learning-Based Generative Model for Evading PDF Malware Classifiers\nYear: 2021\n\nAbstract: Recent research has shown that a small perturbation to an input may forcibly change the prediction of a machine learning (ML) model. Such variants are commonly referred to as adversarial examples. Early studies have focused mostly on ML models for image processing and expanded to other applications, including those for malware classification. In this article, we focus on the probl...","Title: Data Embedding Scheme for Efficient Program Behavior Modeling With Neural Networks\nYear: 2022\n\nAbstract: As modern programs grow in size and complexity, the importance of program behavior modeling is emerging in various areas. Because of the large amount of data generated by a target program and the difficulty of runtime analysis, previous works in these areas employ deep learning. However, they did not sufficiently consider the input of a target program, since, in our view, program behavior is a history of computational steps consisting of a function and its input arguments. A naive, intuitive way to embed the value of \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><tex-math notation=\"LaTeX\">$x$</tex-math></inline-formula>\n as it is in a vector representation creates a tremendously large vector size. Instead, we found that all the values inducing the same runtime behavior can be represented as one identical \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">characteristic value</i>\n (CV). In this paper, we show that not only can a \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">characteristic value</i>\n sequence replace the argument input, but it is also efficient to use it as an input vector for a neural network. This efficiency comes from modeling the whole program with multiple LSTM-RNN models and reducing the input space of the neural network. To demonstrate the effectiveness of this replacement, we performed experiments on the problem of program behavior anomaly detection. Our results show that our model achieves better detection performance compared to previous models and similar detection performance even with smaller model sizes. We also provide a visualization of the embedded vectors extracted from the embedding layer in the neural network model to prove that the CV sequence well represents the arguments.","Title: XTENSTORE: Fast Shielded In-memory Key-Value Store on a Hybrid x86-FPGA System\nYear: 2022\n\nAbstract: We propose XTENSTORE, a system that extends the existing SGX-based secure in-memory key-value store with an external hardware accelerator in order to ensure comparable security guarantees with lower performance degradation. The accelerator is implemented on a commodity FPGA card that is readily connected with the x86 CPU via PCIe interconnect to form a hybrid x86-FPGA system. In comparison to the prior SGX-based work, XTENSTORE improves the throughput by 4-33x, and exhibits considerably shorter tail latency (>23x, 99th-percentile).","Title: Precise Extraction of Deep Learning Models via Side-Channel Attacks on Edge/Endpoint Devices\nYear: 2022\n\nAbstract: With growing popularity, deep learning (DL) models are becoming larger-scale, and only the companies with vast training datasets and immense computing power can manage their business serving such large models. Most of those DL models are proprietary to the companies who thus strive to keep their private models safe from the model extraction attack (MEA), whose aim is to steal the model by training surrogate models. Nowadays, companies are inclined to offload the models from central servers to edge/endpoint devices. As revealed in the latest studies, adversaries exploit this opportunity as new attack vectors to launch side-channel attack (SCA) on the device running victim model and obtain various pieces of the model information, such as the model architecture (MA) and image dimension (ID). Our work provides a comprehensive understanding of such a relationship for the first time and would benefit future MEA studies in both offensive and defensive sides in that they may learn which pieces of information exposed by SCA are more important than the others. Our analysis additionally reveals that by grasping the victim model information from SCA, MEA can get highly effective and successful even without any prior knowledge of the model. Finally, to evince the practicality of our analysis results, we empirically apply SCA, and subsequently, carry out MEA under realistic threat assumptions. The results show up to 5.8 times better performance than when the adversary has no model information about the victim model."],"string":"[\n \"Title: Memory access optimization in compilation for coarse-grained reconfigurable architectures\\nYear: 2011\\n\\nAbstract: Coarse-grained reconfigurable architectures (CGRAs) promise high performance at high power efficiency. They fulfil this promise by keeping the hardware extremely simple, and moving the complexity to application mapping. One major challenge comes in the form of data mapping. For reasons of power-efficiency and complexity, CGRAs use multibank local memory, and a row of PEs share memory access. In order for each row of the PEs to access any memory bank, there is a hardware arbiter between the memory requests generated by the PEs and the banks of the local memory. However, a fundamental restriction remains in that a bank cannot be accessed by two different PEs at the same time. We propose to meet this challenge by mapping application operations onto PEs and data into memory banks in a way that avoids such conflicts. To further improve performance on multibank memories, we propose a compiler optimization for CGRA mapping to reduce the number of memory operations by exploiting data reuse. Our experimental results on kernels from multimedia benchmarks demonstrate that our local memory-aware compilation approach can generate mappings that are up to 53% better in performance (26% on average) compared to a memory-unaware scheduler.\",\n \"Title: Two versions of architectures for dynamic implied addressing mode\\nYear: 2010\\n\\nAbstract: The complexity of today's embedded applications increases with various requirements such as execution time, code size or power consumption. To satisfy these requirements for performance, efficient instruction set design is one of the important issues because an instruction customized for specific applications can make better performance than multiple instructions in aspect of fast execution time, decrease of code size, and low power consumption. Limited encoding space, however, does not allow adding application specific and complex instructions freely to the instruction set architecture. To resolve this problem, conventional architectures increases free space for encoding by trimming excessive bits required beyond the fixed word length. This approach however shows severe weakness in terms of the complexity of compiler, code size and execution time. In this paper, we propose a new instruction encoding scheme based on the dynamic implied addressing mode (DIAM) to resolve limited encoding space and side-effect by trimming. We report our two versions of architectures to support our DIAM-based approach. In the first version, we use a special on-chip memory to store extra encoding information. In the second version, we replace the memory by a small on-chip buffer along with a special instruction. We also suggest a code generation algorithm to fully utilize DIAM. In our experiment, the architecture augmented with DIAM shows about 8% code size reduction and 18% speed up on average, as compared to the basic architecture without DIAM.\",\n \"Title: Vigilare: toward snoop-based kernel integrity monitor\\nYear: 2012\\n\\nAbstract: In this paper, we present Vigilare system, a kernel integrity monitor that is architected to snoop the bus traffic of the host system from a separate independent hardware. This snoop-based monitoring enabled by the Vigilare system, overcomes the limitations of the snapshot-based monitoring employed in previous kernel integrity monitoring solutions. Being based on inspecting snapshots collected over a certain interval, the previous hardware-based monitoring solutions cannot detect transient attacks that can occur in between snapshots. We implemented a prototype of the Vigilare system on Gaisler's grlib-based system-on-a-chip (SoC) by adding Snooper hardware connections module to the host system for bus snooping. To evaluate the benefit of snoop-based monitoring, we also implemented similar SoC with a snapshot-based monitor to be compared with. The Vigilare system detected all the transient attacks without performance degradation while the snapshot-based monitor could not detect all the attacks and induced considerable performance degradation as much as 10% in our tuned STREAM benchmark test.\",\n \"Title: Iterative Algorithm for Compound Instruction Selection with Register Coalescing\\nYear: 2009\\n\\nAbstract: A compound instruction, encoding several ALU or memory operations within an instruction word, has been regarded as an efficient way of improving performance. In the compiler for embedded processors, the code generation algorithm for compound instructions has been built by dealing mainly with instruction selection which is a crucial phase of code generation. In this paper, we propose an iterative code generation algorithm for minimizing the detrimental impact of register coalescing that is applied to the code with compound instructions generated earlier from the instruction selection phase.\",\n \"Title: Unified Interprocedural Parallelism Detection\\nYear: 2001\\n\\nAbstract: In this paper, we outline a new way of detecting parallelism interprocedurally within a program. Our method goes beyond mere dependence testing, to embrace methods of removing dependences as well, namely privatization, induction recognition and reduction recognition. This method is based on a combination of techniques: a “universal” form for representing memory accesses within a section of code (the Linear Memory Access Descriptor), a technique for classifying memory locations based on the accesses made to them by the code (Memory Classification Analysis), and a dependence test (the Access Region Test). The analysis done with Linear Memory Access Descriptors is based on an intersection operation, for which we present an algorithm. Linear Memory Access Descriptors are independent of any declarations that may exist in a program, so they are subroutine- and language-independent. This makes them ideal for use in interprocedural analysis. Our experiments indicate that this test is highly effective for parallelizing loops containing very complex subscript expressions.\",\n \"Title: Parallel Programming with Polaris\\nYear: 1996\\n\\nAbstract: As we reach the technological limits of hardware improvement, we must rely on multiple processors to improve programming speed. Parallel programming tools are limited, making effective parallel programming difficult and cumbersome. Compilers that translate conventional sequential programs into parallel form would liberate programmers from the complexities of explicit, machine-oriented parallel programming. Polaris, an experimental translator of conventional Fortran programs that target machines such as the Cray T3D, is the first step toward this goal. The most important techniques implemented in Polaris resulted from a study of the effectiveness of commercial Fortran parallelizers. The authors compiled the Perfect Benchmarks, a collection of conventional Fortran programs representing the typical workload of high-performance computers, for the Alliant FX/80, an eight-processor multiprocessor popular in the late 1980s. For each program, they measured the quality of the parallelization by computing the speedup. With few exceptions, the Alliant Fortran compiler failed to deliver any significant speedup for the majority of the programs. The compiler failed to produce a speedup because it could not parallelize some of the most important loops in the Perfect Benchmarks. The study showed that extending the four most important analysis and transformation techniques traditionally used for vectorization leads to significant increases in speedup. Polaris detected much of the parallelism available in the set of benchmark codes. A careful analysis of the remaining loops that Polaris could parallelize highlights four areas for improvement.\",\n \"Title: Case Studies on Automatic Extraction of Target-Specific Architectural Parameters in Complex Code Generation\\nYear: 2003\\n\\nAbstract: To cope with the highly complex and irregular embedded processor architectures, we employ the two traditionally-known most aggressive and computationally expensive code generation methods. One is integrated code generation where two main subproblems of code generation, instruction selection and register allocation, are simultaneously solved. The other is directed acyclic graph (DAG) covering, not tree covering, for code generation. In principle, unifying these two expensive methods may increase compilation time prohibitively. However often in practice, we have observed that the overall time can be manageably short without degrading the code quality by adding a few heuristics that fully capitalize on specific characteristics of target processor models.\",\n \"Title: Exploiting both pipelining and data parallelism with SIMD reconfigurable architecture\\nYear: 2012\\n\\nAbstract: Reconfigurable Architecture (RA), which provides extremely high energy efficiency for certain domains of applications, have one problem that current mapping algorithms for it do not scale well with the number of cores. One approach to this problem is using SIMD (Single Instruction Multiple Data) paradigm. However, SIMD can complicate the mapping problem by adding an additional dimension, i.e., iteration mapping, to the already inter-dependent problems of data mapping and operation mapping, and can significantly affect performance through memory bank conflicts. In this paper we introduce SIMD reconfigurable architecture, which allows for SIMD mapping at multiple levels of granularity, and investigate ways to minimize bank conflicts in a SIMD reconfigurable architecture with the related sub-problems taken into consideration. We further present data tiling and evaluate a conflict-free scheduling algorithm as a way to eliminate bank conflicts for a certain class of iteration and data mapping.\",\n \"Title: Automatic generation of operation tables for fast exploration of bypasses in embedded processors\\nYear: 2006\\n\\nAbstract: Customizing the bypasses in an embedded processor uncovers valuable trade-offs between the power, performance and the cost of the processor. Meaningful exploration of bypasses requires bypass-sensitive compiler. Operation tables (OTs) have been proposed to perform bypass-sensitive compilation. However, due to lack of automated methods to generate OTs, OTs are currently manually specified by the designer. Manual specification of OTs is not only an extremely time consuming task, but is also highly error-prone. In this paper, we present AutoOT, an algorithm to automatically generate OTs from a high-level processor description. Our experiments on the Intel XScale processor model running MiBench benchmarks demonstrate that AutoOT greatly reduces the time and effort of specification. Automatic generation of OTs makes it feasible to perform full bypass exploration on the Intel XScale and thus discover interesting alternate bypass configurations in a reasonable time. To further reduce the compile-time overhead of OT generation, we propose another novel algorithm, AutoOTDB. AutoOTDB is able to cut the compile-time overhead of OT generation by half\",\n \"Title: Automatic Parallelization for Non-cache Coherent Multiprocessors\\nYear: 1996\\n\\nAbstract: Abstract: Although much work has been done on parallelizing compilers for cachecoherent shared memory multiprocessors and message-passing multiprocessors,there is relatively little research on parallelizing compilers for noncachecoherent multiprocessors with global address space. In this paper,we present a preliminary study on automatic parallelization for the CrayT3D, a commercial scalable machine with a global memory space and noncoherentcaches.\",\n \"Title: Fast graph-based instruction selection for multi-output instructions\\nYear: 2011\\n\\nAbstract: A multi-output instruction (MOI) is an instruction that produces multiple outputs to its destination locations. Such inherently parallel instructions are becoming more and more popular in embedded processors, due to the advances in application-specific architectures. In order to provide high-level programmability and thus guarantee widespread acceptance, sophisticated compiler support for these programmable cores is necessary. However, traditional tree-based approaches for instruction selection, although very fast, fail to exploit MOIs mainly because of the fundamental limitation of the tree representation. In fact, to generate optimal code with MOIs requires a more general graph-based formulation of the instruction selection problem, which is at least NP-complete. In this paper we present a new methodology to automatically generate from simple instruction set descriptions, graph-based code selectors that can effectively utilize all provided instructions including MOIs. Our experimental results using a set of benchmarks on a target processor with various MOIs of up to two outputs demonstrate that our generated code selectors can quickly and effectively exploit many MOIs at the application level, and therefore are highly desirable both for architecture exploration and as code generators after architecture is fixed. Copyright © 2010 John Wiley & Sons, Ltd. (This is a revised and expanded version of a paper published in the Fifth IEEE/ACM International Conference on Hardware/Software Codesign and System Synthesis (CODES+ISSS), September 2007 1.)\",\n \"Title: Compiler Techniques for Effective Communication on Distributed-Memory Multiprocessors\\nYear: 1997\\n\\nAbstract: The Polaris restructurer transforms conventional Fortran programs into parallel form for various types of multiprocessor systems. This paper presents the results of a study on strategies to improve the effectiveness of Polaris' techniques for distributed-memory multiprocessors. Our study, which is based on the hand analysis of MDG and TRFD from the Perfect Benchmarks and TOMCATV and SWIM from SPEC benchmarks, identified three techniques that are important for improving communication optimization. Their application produces almost perfect speedups for the four programs on the Cray T3D.\",\n \"Title: Reducing instruction bit-width for low-power VLIW architectures\\nYear: 2013\\n\\nAbstract: VLIW (very long instruction word) architectures have proven to be useful for embedded applications with abundant instruction level parallelism. But due to the long instruction bus width it often consumes more power and memory space than necessary. One way to lessen this problem is to adopt a reduced bit-width instruction set architecture (ISA) that has a narrower instruction word length. This facilitates a more efficient hardware implementation in terms of area and power by decreasing bus-bandwidth requirements and the power dissipation associated with instruction fetches. In practice, however, it is impossible to convert a given ISA fully into an equivalent reduced bit-width one because the narrow instruction word, due to bit-width restrictions, can encode only a small subset of normal instructions in the original ISA. Consequently, existing processors provide narrow instructions in very limited cases along with severe restrictions on register accessibility. The objective of this work is to explore the possibility of complete conversion, as a case study, of an existing 32-bit VLIW ISA into a 16-bit one that supports effectively all 32-bit instructions. To this objective, we attempt to circumvent the bit-width restrictions by dynamically extending the effective instruction word length of the converted 16-bit operations. Further, we will show that our proposed ISA conversion can create a synergy effect with a VLES (variable length execution set) architecture that is adopted in most recent VLIW processors. According to our experiment, the code size becomes significantly smaller after the conversion to 16-bit VLIW code. Also at a slight run time cost, the machine with the 16-bit ISA consumes much less energy than the original machine.\",\n \"Title: Architecture customization of on-chip reconfigurable accelerators\\nYear: 2013\\n\\nAbstract: Integrating coarse-grained reconfigurable architectures (CGRAs) into a System-on-a-Chip (SoC) presents many benefits as well as important challenges. One of the challenges is how to customize the architecture for the target applications efficiently and effectively without performing explicit design space exploration. In this article we present a novel methodology for incremental interconnect customization of CGRAs that can suggest a new interconnection architecture which is able to maximize the performance for a given set of application kernels while minimizing the hardware cost. In our methodology, we translate the problem of interconnect customization into that of inexact graph matching, and we devised a heuristic for A* search algorithm to efficiently solve the inexact graph matching problem. Our experimental results demonstrate that our customization method can quickly find application-optimized interconnections that exhibit 80% higher performance on average compared to the base architecture which has mesh interconnections, with little energy and hardware increase in interconnections and muxes.\",\n \"Title: A retargetable parallel-programming framework for MPSoC\\nYear: 2008\\n\\nAbstract: As more processing elements are integrated in a single chip, embedded software design becomes more challenging: It becomes a parallel programming for nontrivial heterogeneous multiprocessors with diverse communication architectures, and design constraints such as hardware cost, power, and timeliness. In the current practice of parallel programming with MPI or OpenMP, the programmer should manually optimize the parallel code for each target architecture and for the design constraints. Thus, the design-space exploration of MPSoC (multiprocessor systems-on-chip) costs become prohibitively large as software development overhead increases drastically. To solve this problem, we develop a parallel-programming framework based on a novel programming model called common intermediate code (CIC). In a CIC, functional parallelism and data parallelism of application tasks are specified independently of the target architecture and design constraints. Then, the CIC translator translates the CIC into the final parallel code, considering the target architecture and design constraints to make the CIC retargetable. Experiments with preliminary examples, including the H.263 decoder, show that the proposed parallel-programming framework increases the design productivity of MPSoC software significantly.\",\n \"Title: A graph drawing based spatial mapping algorithm for coarse-grained reconfigurable architectures\\nYear: 2009\\n\\nAbstract: Recently coarse-grained reconfigurable architectures (CGRAs) have drawn increasing attention due to their efficiency and flexibility. While many CGRAs have demonstrated impressive performance improvements, the effectiveness of CGRA platforms ultimately hinges on the compiler. Existing CGRA compilers do not model the details of the CGRA, and thus they are i) unable to map applications, even though a mapping exists, and ii) using too many processing elements (PEs) to map an application. In this paper, we model several CGRA details, e.g., irregular CGRA topologies, shared resources and routing PEs in our compiler and develop a graph drawing based approach, Split-Push Kernel Mapping (SPKM), for mapping applications onto CGRAs. On randomly generated graphs our technique can map on average 4.5× more applications than the previous approach, while generating mappings which have better qualities in terms of utilized CGRA resources. Utilizing fewer resources is directly translated into increased opportunities for novel power and performance optimization techniques. Our technique shows less power consumption in 71 cases and shorter execution cycles in 66 cases out of 100 synthetic applications, with minimum mapping time overhead. We observe similar results on a suite of benchmarks collected from Livermore loops, Mediabench, Multimedia, Wavelet and DSPStone benchmarks. SPKM is not a customized algorithm only for a specific CGRA template, and it is demonstrated by exploring various PE interconnection topologies and shared resource configurations with SPKM.\",\n \"Title: Operation and data mapping for CGRAs with multi-bank memory\\nYear: 2010\\n\\nAbstract: Coarse Grain Reconfigurable Architectures (CGRAs) promise high performance at high power efficiency. They fulfil this promise by keeping the hardware extremely simple, and moving the complexity to application mapping. One major challenge comes in the form of data mapping. For reasons of power-efficiency and complexity, CGRAs use multi-bank local memory, and a row of PEs share memory access. In order for each row of the PEs to access any memory bank, there is a hardware arbiter between the memory requests generated by the PEs and the banks of the local memory. However, a fundamental restriction remains that a bank cannot be accessed by two different PEs at the same time. We propose to meet this challenge by mapping application operations onto PEs and data into memory banks in a way that avoids such conflicts. Our experimental results on kernels from multimedia benchmarks demonstrate that our local memory-aware compilation approach can generate mappings that are up to 40% better in performance (17.3% on average) compared to a memory-unaware scheduler.\",\n \"Title: A Study on Data Allocation of On-Chip Dual Memory Banks\\nYear: 2002\\n\\nAbstract: Embedded systems require control of many concurrent real-time activities, leading to system designs which feature multiple hardware peripherals with each providing a specific, dedicated service. These peripherals increase system size, cost, weight, power ...\",\n \"Title: Memory-Aware application mapping on coarse-grained reconfigurable arrays\\nYear: 2010\\n\\nAbstract: Coarse-Grained Reconfigurable Arrays (CGRAs) are a very promising platform, providing both, up to 10-100 MOps/mW of power efficiency and are software programmable. However, this cardinal promise of CGRAs critically hinges on the effectiveness of application mapping onto CGRA platforms. While previous solutions have greatly improved the computation speed, they have largely ignored the impact of the local memory architecture on the achievable power and performance. This paper motivates the need for memory-aware application mapping for CGRAs, and proposes an effective solution for application mapping that considers the effects of various memory architecture parameters including the number of banks, local memory size, and the communication bandwidth between the local memory and the external main memory. Our proposed solution achieves 62% reduction in the energy-delay product, which factors into about 47% and 28% reduction in the energy consumption and runtime, respectively, as compared to memory-unaware mapping for realistic local memory architectures. We also show that our scheme scales across a range of applications, and memory parameters.\",\n \"Title: Efficient embedded code generation with multiple load-store instructions\\nYear: 2007\\n\\nAbstract: In a recent study, we discovered that many single load-store operations in embedded applications can be parallelized and thus encoded simultaneously in a single-instruction multiple-data instruction, called the multiple load-store (MLS) instruction. In this work, we investigate the problem of utilizing MLS instructions to produce optimized machine code, and propose an effective approach to the problem. Specifically, we formalize the MLS problem, that is, the problem of maximizing the use of MLS instructions with an unlimited register file size. Based on this analysis, we show that we can solve the problem efficiently by translating it into a variant of the problem finding a maximum weighted path cover in a dynamic weighted graph. To handle a more realistic case of the finite size of the register file, our solution is then extended to take into account the constraints of register sequencing in MLS instructions and the limited register resource available in the target processor. We demonstrate the effectiveness of our approach experimentally by using a set of benchmark programs. In summary, our approach can reduce the number of loads-stores by 13.3% on average, compared with the code generated from existing compilers. The total code size reduction is 3.6%. This code size reduction comes at almost no cost because the overall increase in compilation time as a result of our technique remains quite minimal. Copyright © 2007 John Wiley & Sons, Ltd.\",\n \"Title: Fast dynamic execution offloading for efficient mobile cloud computing\\nYear: 2013\\n\\nAbstract: In order to meet the increasing demand for high performance in smartphones, recent studies suggested mobile cloud computing techniques that aim to connect the phones to adjacent powerful cloud servers to throw their computational burden to the servers. These techniques often employ execution offloading schemes that migrate a process between machines during its execution. In execution offloading, code regions to be executed on the server are decided statically or dynamically based on the complex analysis on execution time and process state transfer time of every region. Expectedly, the transfer time is a deciding factor for the success of execution offloading. According to our analysis, it is dominated by the total size of heap objects transferred over the network. But previous work did not try hard to minimize this size. Thus in this paper, we introduce novel techniques based on compiler code analysis that effectively reduce the transferred data size by transferring only the essential heap objects. The experiments exhibit that the reduced size positively influences not only the transfer time itself but also the overall effectiveness of execution offloading, and ultimately, improves the performance of our mobile cloud computing significantly in terms of execution time and power consumption.\",\n \"Title: Adaptive Scratch Pad Memory Management for Dynamic Behavior of Multimedia Applications\\nYear: 2009\\n\\nAbstract: Exploiting runtime memory access traces can be a complementary approach to compiler optimizations for the energy reduction in memory hierarchy. This is particularly important for emerging multimedia applications since they usually have input-sensitive runtime behavior which results in dynamic and/or irregular memory access patterns. These types of applications are normally hard to optimize by static compiler optimizations. The reason is that their behavior stays unknown until runtime and may even change during computation. To tackle this problem, we propose an integrated approach of software [compiler and operating system (OS)] and hardware (data access record table) techniques to exploit data reusability of multimedia applications in Multiprocessor Systems on Chip. Guided by compiler analysis for generating scratch pad data layouts and hardware components for tracking dynamic memory accesses, the scratch pad data layout adapts to an input data pattern with the help of a runtime scratch pad memory manager incorporated in the OS. The runtime data placement strategy presented in this paper provides efficient scratch pad utilization for the dynamic applications. The goal is to minimize the amount of accesses to the main memory over the entire runtime of the system, which leads to a reduction in the energy consumption of the system. Our experimental results show that our approach is able to significantly improve the energy consumption of multimedia applications with dynamic memory access behavior over an existing compiler technique and an alternative hardware technique.\",\n \"Title: A Parallel Programming Environment for a V-Busbased PC-cluster\\nYear: 2001\\n\\nAbstract: Nowadays PC-cluster architectures are widely accepted forparallel computing.In a PC-cluster system, memories are physicallydistributed.To harness thecomputational power of a distributed-memoryPC-cluster, a user must writeefficient software for the machine by hand. The absence of globaladdress space makes the process laborious because theuser must manually assign computations to processors, distribute data acrossprocessors andexplicitly manage communication among processors. This paperintroduces ourrecent three related studies on parallel computing. The first isem a V-Busbased PC-cluster in which all PCs are interconnected through V-Busnetworkcards. The second is the implementation of an one-sidedcommunicationlibrary on our PC-cluster system, which provides the user with aview ofglobal address space on top of the distributed-memory PC-cluster.Thisencapsulation of global address allows the user to write shared memory codeonour cluster system, which simplifies programming our cluster because theuserdoes not need to explicitly cope with distributed memories. The third is aparallelizing compiler that automatically translates a sequential code toashared-memory code for the PC-cluster. This compiler not only enables legacycodeto be compiled for our cluster, but also further simplifies programmingourcluster by allowing the user to continue using conventional sequentiallanguagessuch as Fortran 77.In this work, the compiler was optimizedparticularlyfor our V-Bus based PC-cluster. The paper also reports ourexperimental resultswith the compiler on our PC-cluster system.\",\n \"Title: Compiling for Scalable Multiprocessors with Polaris\\nYear: 1997\\n\\nAbstract: yThe lack of cache coherence mechanisms introducessome challenges to the programming of distributedmemory machines with a globally addressable memory.The reason is that, in these machines, softwareneeds explicit control of cacheability and coherency. Tosimplify programming, and increase reliability and reducedevelopment costs as a consequence, it is necessaryto automatically generate the statements that controlcacheability and coherency. To generate these statements,a compiler needs...\",\n \"Title: Software controlled memory layout reorganization for irregular array access patterns\\nYear: 2007\\n\\nAbstract: Many embedded array-intensive applications have irregular access patterns that are not amenable to static analysis for extraction of access patterns, and thus prevent efficient use of a Scratch Pad Memory (SPM) hierarchy for performance and power improvement. We present a profiling based strategy that generates a memory access trace which can be used to identify data elements with fine granularity that can profitably be placed in the SPMs to maximize performance and energy gains. We developed an entire toolchain that allows incorporation of the code required to profitably move data to SPMs; visualization of the extracted access pattern after profiling; and evaluation/exploration of the generated application code to steer mapping of data to the SPM to yield performance and energy benefits.We present a heuristic approach that efficiently exploits the SPM using the profiler-driven access pattern behaviors. Experimental results on EEMBC and other industrial codes obtained with our framework show that we are able to achieve 36% energy reduction and reduce execution time by up to 22% compared to a cache based system.\",\n \"Title: Selective validations for efficient protections on Coarse-Grained Reconfigurable Architectures\\nYear: 2013\\n\\nAbstract: Coarse-Grained Reconfigurable Architectures or CGRAs are drawing significant attention since they promise both performance with parallelism and flexibility with reconfiguration. Soft errors or transient faults are becoming a serious design concern in embedded systems including CGRAs since soft error rate is increasing exponentially as technology scaling. A recently proposed software-based technique with TMR (Triple Modular Redundancy) implemented on CGRAs incurs extreme performance overhead mainly due to expensive voting mechanisms for outputs from triplication of every operation. In this paper, we propose selective validation mechanisms for efficient modular redundancy techniques in the datapaths on CGRAs. Our techniques selectively validate results at synchronous operations rather than every operation in order to reduce the expensive performance overhead from the validation mechanism. Our experimental results demonstrate that our selective validation based TMR technique can improve the performance by 38.3% on average over benchmarks as compared to the recently proposed software-based TMR technique with the full validation.\",\n \"Title: Efficient register and memory assignment for non-orthogonal architectures via graph coloring and MST algorithms\\nYear: 2002\\n\\nAbstract: Finding an optimal assignment of program variables into registers and memory is prohibitively difficult in code generation for application specific instruction-set processors (ASIPs). This is mainly because, in order to meet stringent speed and power requirements for embedded applications, ASIPs commonly employ non-orthogonal architectures which are typically characterized by irregular data paths, heterogeneous registers and multiple memory banks. As a result, existing techniques mainly developed for relatively regular, orthogonal general-purpose processors (GPPs) are obsolete for these recently emerging ASIP architectures. In this paper, we attempt to tackle this issue by exploiting conventional graph coloring and maximum spanning tree (MST) algorithms with special constraints added to handle the non-orthogonality of ASIP architectures. The results in our study indicate that our algorithm finds a fairly good assignment of variables into heterogeneous registers and multi-memories while it runs extremely faster than previous work that employed exceedingly expensive algorithms to address this issue.\",\n \"Title: High Throughput Data Mapping for Coarse-Grained Reconfigurable Architectures\\nYear: 2011\\n\\nAbstract: Coarse-grained reconfigurable arrays (CGRAs) are a very promising platform, providing both up to 10–100 MOps/mW of power efficiency and software programmability. However, this promise of CGRAs critically hinges on the effectiveness of application mapping onto CGRA platforms. While previous solutions have greatly improved the computation speed, they have largely ignored the impact of the local memory architecture on the achievable power and performance. This paper motivates the need for memory-aware application mapping for CGRAs, and proposes an effective solution for application mapping that considers the effects of various memory architecture parameters including the number of banks, local memory size, and the communication bandwidth between the local memory and the external main memory. Further we propose efficient methods to handle dependent data on a double-buffering local memory, which is necessary for recurrent loops. Our proposed solution achieves 59% reduction in the energy-delay product, which factors into about 47% and 22% reduction in the energy consumption and runtime, respectively, as compared to memory-unaware mapping for realistic local memory architectures. We also show that our scheme scales across a range of applications and memory parameters, and the runtime overhead of handling recurrent loops by our proposed methods can be less than 1%.\",\n \"Title: Hiding cache miss penalty using priority-based execution for embedded processors\\nYear: 2008\\n\\nAbstract: The contribution of memory latency to execution time continues to increase, and latency hiding mechanisms become ever more important for efficient processor design. While high-end processors can use elaborate techniques like multiple issue, out-of-order execution, speculative execution, value prediction etc. to tolerate high memory latencies, they are often not viable solutions for embedded processors, due to significant area, power and chip complexity overheads. This paper proposes a hardware-software cooperative approach, called priority-based execution to hide cache miss penalty for embedded processors. The compiler classifies the instructions into low-priority and high-priority instructions. The processor executes the high-priority instructions, but delays the execution of low priority instructions. They are executed on a cache miss to hide the cache miss penalty. We empirically evaluate our proposal on the Intel XScale compiler and microarchitecture. Experimental results on bench-marks from Multimedia, Media Bench, MiBench, and SPEC2000 demonstrate an average 17% performance improvements, hiding 75% cache miss penalty.\",\n \"Title: Exploiting parallelism in memory operations for code optimization\\nYear: 2004\\n\\nAbstract: Code size reduction is ever becoming more important for compilers targeting embedded processors because these processors are often severely limited by storage constraints and thus the reduced code size can have a positively significant impact on their performance. Various code size reduction techniques have different motivations and a variety of application contexts utilizing special hardware features of their target processors. In this work, we propose a novel technique that fully utilizes a set of hardware instructions, called the multiple load/store (MLS) or parallel load/store (PLS), that are specially featured for reducing code size by minimizing the number of memory operations in the code. To take advantage of this feature, many microprocessors support the MLS instructions, whereas no existing compilers fully exploit the potential benefit of these instructions but only use them for some limited cases. This is mainly because optimizing memory accesses with MLS instructions for general cases is an NP-hard problem that necessitates complex assignments of registers and memory offsets for variables in a stack frame. Our technique uses a couple of heuristics to efficiently handle this problem in a polynomial time bound.\",\n \"Title: Simplification of array access patterns for compiler optimizations\\nYear: 1998\\n\\nAbstract: Existing array region representation techniques are sensitive to the complexity of array subscripts. In general, these techniques are very accurate and efficient for simple subscript expressions, but lose accuracy or require potentially expensive algorithms for complex subscripts. We found that in scientific applications, many access patterns are simple even when the subscript expressions are complex. In this work, we present a new, general array access representation and define operations for it. This allows us to aggregate and simplify the representation enough that precise region operations may be applied to enable compiler optimizations. Our experiments show that these techniques hold promise for speeding up applications.\",\n \"Title: Run-Time memory optimization for DDMB architecture through a CCB algorithm\\nYear: 2006\\n\\nAbstract: Most vendors of digital signal processors (DSPs) support a Harvard architecture, which has two or more memory buses, one for program and one or more for data and allow the processor to access multiple words of data from memory in a single instruction cycle. We already addressed how to efficiently assign data to multi-memory banks in our previous work. This paper reports on our recent attempt to optimize run-time memory. The run-time environment for dual data memory banks (DDMBs) requires two run-time stacks to control activation records located in two memory banks corresponding to calling procedures. However, activation records of two memory banks for a procedure are able to have different size. As a consequence, dual run-time stacks can be unbalanced whenever a procedure is called. This unbalance between two memory banks causes that usage of one memory bank can exceed the extent of on-chip memory area although there is free area in the other memory bank. We attempt balancing dual run-time stacks to enhance efficiently utilization of on-chip memory in this paper. The experimental results have revealed that although our call chain balancing (CCB) algorithm is relatively quite simple, it still can utilize run-time memories efficiently; thus enabling our compiler to run extremely fast, yet minimizing the usage of run-time memory in the target code.\",\n \"Title: SPKM: a novel graph drawing based algorithm for application mapping onto coarse-grained reconfigurable architectures\\nYear: 2008\\n\\nAbstract: Recently coarse-grained reconfigurable architectures (CGRAs) have drawn increasing attention due to their efficiency and flexibility. While many CGRAs have demonstrated impressive performance improvements, the effectiveness of CGRA platforms ultimately hinges on the compiler. Existing CGRA compilers do not model the details of the CGRA architecture, due to which they are, i) unable to map applications, even though a mapping exists, and ii) use too many PEs to map an application. In this paper, we model several CGRA details in our compiler and develop a graph mapping based approach (SPKM) for mapping applications onto CGRAs. On randomly generated graphs our technique can map on average 4.5X more applications than the previous approaches, while using fewer CGRA rows 62% times, without any penalty in mapping time. We observe similar results on a suite of benchmarks collected from Livermore Loops, Multimedia and DSPStone benchmarks.\",\n \"Title: VISTA: VPO interactive system for tuning applications\\nYear: 2006\\n\\nAbstract: Software designers face many challenges when developing applications for embedded systems. One major challenge is meeting the conflicting constraints of speed, code size, and power consumption. Embedded application developers often resort to hand-coded assembly language to meet these constraints since traditional optimizing compiler technology is usually of little help in addressing this challenge. The results are software systems that are not portable, less robust, and more costly to develop and maintain. Another limitation is that compilers traditionally apply the optimizations to a program in a fixed order. However, it has long been known that a single ordering of optimization phases will not produce the best code for every application. In fact, the smallest unit of compilation in most compilers is typically a function and the programmer has no control over the code improvement process other than setting flags to enable or disable certain optimization phases. This paper describes a new code improvement paradigm implemented in a system called VISTA that can help achieve the cost/performance trade-offs that embedded applications demand. The VISTA system opens the code improvement process and gives the application programmer, when necessary, the ability to finely control it. VISTA also provides support for finding effective sequences of optimization phases. This support includes the ability to interactively get static and dynamic performance information, which can be used by the developer to steer the code improvement process. This performance information is also internally used by VISTA for automatically selecting the best optimization sequence from several attempted. One such feature is the use of a genetic algorithm to search for the most efficient sequence based on specified fitness criteria. We include a number of experimental results that evaluate the effectiveness of using a genetic algorithm in VISTA to find effective optimization phase sequences.\",\n \"Title: Register File Power Reduction Using Bypass Sensitive Compiler\\nYear: 2008\\n\\nAbstract: This paper explores, develops, and investigates several bypass-sensitive compilation techniques to reduce the register file power by reducing the access frequency to the register file. We study the effectiveness of our techniques on the Intel XScale processor, which is based on the previously proposed ldquoon-demand register fetch readrdquo architectural feature. Furthermore, we show that our bypass-sensitive compilation technique is effective on various partial bypass configurations.\",\n \"Title: Improving performance of loops on DIAM-based VLIW architectures\\nYear: 2014\\n\\nAbstract: Recent studies show that very long instruction word (VLIW) architectures, which inherently have wide datapath (e.g. 128 or 256 bits for one VLIW instruction word), can benefit from dynamic implied addressing mode (DIAM) and can achieve lower power consumption and smaller code size with a small performance overhead. Such overhead, which is claimed to be small, is mainly caused by the execution of additionally generated special instructions for conveying information that cannot be encoded in reduced instruction bit-width. In this paper, however, we show that the performance impact of applying DIAM on VLIW architecture cannot be overlooked expecially when applications possess high level of instruction level parallelism (ILP), which is mostly the case for loops because of the result of aggressive code scheduling. We also propose a way to relieve the performance degradation especially focusing on loops since loops spend almost 90% of total execution time in programs and tend to have high ILP. We first implement the original DIAM compilation technique in a compiler, and augment it with the proposed loop optimization scheme to show that ours can clearly alleviate the performance loss caused by the excessive number of additional instructions, with the help of slightly modified hardware. Moreover, the well-known loop unrolling scheme, which would produce denser code in loops at the cost of substantial code size bloating, is integrated into our compiler. The experiment result shows that the loop unrolling technique, combined with our augmented DIAM scheme, produces far better code in terms of performance with quite an acceptable amount of code increase.\",\n \"Title: Instruction re-selection for iterative modulo scheduling on high performance multi-issue DSPs\\nYear: 2006\\n\\nAbstract: An iterative modulo scheduling is very important for compilers targeting high performance multi-issue digital signal processors. This is because these processors are often severely limited by idle state functional units and thus the reduced idle units can have a positively significant impact on their performance. However, complex instructions, which are used in most recent DSPs such as mac, usually increase data dependence complexity, and such complex dependencies that exist in signal processing applications often restrict modulo scheduling freedom and therefore, become a limiting factor of the iterative modulo scheduler. In this work, we propose a technique that efficiently reselects instructions of an application loop code considering dependence complexity, which directly resolve the dependence constraint. That is specifically featured for accelerating software pipelining performance by minimizing length of intrinsic cyclic dependencies. To take advantage of this feature, few existing compilers support a loop unrolling based dependence relaxing technique, but only use them for some limited cases. This is mainly because the loop unrolling typically occurs an overhead of huge code size increment, and the iterative modulo scheduling with relaxed dependence techniques for general cases is an NP-hard problem that necessitates complex assignments of registers and functional units. Our technique uses a heuristic to efficiently handle this problem in pre-stage of iterative modulo scheduling without loop unrolling.\",\n \"Title: Preprocessing strategy for effective modulo scheduling on multi-issue digital signal processors\\nYear: 2007\\n\\nAbstract: To achieve high resource utilization for multi-issue Digital Signal Processors (DSPs), production compilers commonly include variants of the iterative modulo scheduling algorithm. However, excessive cyclic data dependences, which exist in communication and media processing loops, often prevent the modulo scheduler from achieving ideal loop initiation intervals. As a result, replicated functional units in multi-issue DSPs are frequently underutilized. In response to this resource underutilization problem, this paper describes a compiler preprocessing strategy that capitalizes on two techniques for effective modulo scheduling, referred to as cloning1 and cloning2. The core of the proposed techniques lies in the direct relaxation of cyclic data dependences by exploiting functional units which are otherwise left unused. Since our preprocessing strategy requires neither code duplication nor additional hardware support, it is relatively easy to implement in DSP compilers. The strategy proposed has been validated by an implementation for a StarCore SC140 optimizing C compiler.\",\n \"Title: Power-Conscious Configuration Cache Structure and Code Mapping for Coarse-Grained Reconfigurable Architecture\\nYear: 2006\\n\\nAbstract: Coarse-grained reconfigurable architecture aims to achieve both performance and flexibility. However, power consumption is no less important for the reconfigurable architecture to be used as a competitive processing core in embedded systems. In this paper, we show how power is consumed in a typical coarse-grained reconfigurable architecture. Based on the power breakdown data, we suggest a power-conscious configuration cache structure and code mapping technique, which reduce power consumption without performance degradation. Experimental results show that the proposed approach saves much power even with reduced configuration cache size\",\n \"Title: Compiler-in-the-loop design space exploration framework for energy reduction in horizontally partitioned cache architectures\\nYear: 2009\\n\\nAbstract: Horizontally partitioned caches (HPCs) are a power-efficient architectural feature in which the processor maintains two or more data caches at the same level of hierarchy. HPCs help reduce cache pollution and thereby improve performance. Consequently, most previous research has focused on exploiting HPCs to improve performance and achieve energy reduction only as a byproduct of performance improvement. However, with energy consumption becoming the first class design constraint, there is an increasing need for compilation techniques aimed at energy reduction itself. This paper proposes and explores several low-complexity algorithms aimed at reducing the energy consumption. Acknowledging that the compiler has a significant impact on the energy consumption of the HPCs, Compiler-in-the-Loop Design Space Exploration methodologies are also presented to carefully choose the HPC parameters that result in minimum energy consumption for the application.\",\n \"Title: Fast Code Generation for Embedded Processors with Aliased Heterogeneous Registers\\nYear: 2009\\n\\nAbstract: Many embedded processors have complex, irregular architectures resulting from the customization for the maximum performance and energy efficiency of target applications. One such example is the heterogeneous register architecture, which has fast, small-sized register files, for their specific uses, distributed over the data paths between different functional units. Although this architectural design may be good at achieving the H/W design goal of high speed, small area and low power, it requires highly expensive algorithms for optimal code generation. This is primarily because multiple registers contained in each file come with many different constraints subject to their design purposes, and often their names are aliased with each other; thus the final code quality is very sensitive to how properly such aliased, heterogeneous registers are utilized in every instruction. In this work, we propose a code generation approach to attack this complex problem. The experiments reveal that our approach is fast, practically running in polynomial time. In comparison with the related work, it achieves approximately 13% of code size reduction and 16% of speed increase.\",\n \"Title: The very portable optimizer for digital signal processors\\nYear: 2001\\n\\nAbstract: Although retargetability has been a major design concern for many compilers, retargetability is a vitally important issue for Digital Signal Processors(DSPs) because the architectural variations of DSPs are much wider than those of General-Purpose Processors (GPPs). This paper describes our preliminary study on a retargetable code generator, called the Very Portable Optimizer (VPO), that has been recently engineered to target DSPs. The compiler was originally implemented to target GPPs, but thanks to its novel intermediate representation designed to support retargetability, it has been successfully retargeted to a commercial DSP within a relatively short period of time. This retargetable compiler study is at its early stage, so the code quality is still amenable to further improvement. However, our recent enhancements to VPO helped us to achieve quite encouraging results when being compared with a production-quality, highly-customized, compiler.\",\n \"Title: Mantis: automatic performance prediction for smartphone applications\\nYear: 2013\\n\\nAbstract: We present Mantis, a framework for predicting the performance of Android applications on given inputs automatically, accurately, and efficiently. A key insight underlying Mantis is that program execution runs often contain features that correlate with performance and are automatically computable efficiently. Mantis synergistically combines techniques from program analysis and machine learning. It constructs concise performance models by choosing from many program execution features only a handful that are most correlated with the program's execution time yet can be evaluated efficiently from the program's input. We apply program slicing to accurately estimate the evaluation cost of a feature and automatically generate executable code snippets for efficiently evaluating features. Our evaluation shows that Mantis predicts the execution time of six Android apps with estimation error in the range of 2.2-11.9% by executing predictor code costing at most 1.3% of their execution time on Galaxy Nexus.\",\n \"Title: A spatial mapping algorithm for heterogeneous coarse-grained reconfigurable architectures\\nYear: 2006\\n\\nAbstract: In this work, we investigate the problem of automatically mapping applications onto a coarse-grained reconfigurable architecture and propose an efficient algorithm to solve the problem. We formalize the mapping problem and show that it is NP-complete. To solve the problem within a reasonable amount of time, we divide it into three subproblems: covering, partitioning and layout. Our empirical results demonstrate that our technique produces nearly as good performance as hand-optimized outputs for many kernels\",\n \"Title: Optimistic coalescing for heterogeneous register architectures\\nYear: 2007\\n\\nAbstract: In this paper, Optimistic coalescing has been proven as an elegant and effective technique that provides better chances of safely coloring more registers in register allocation than other coalescing techniques. Its algorithm originally assumes homogeneous registers which are all gathered in the same register file. Although this register architecture is still common in most general-purpose processors, embedded processors often contain heterogeneous registers which are scattered in physically different register files dedicated for each dissimilar purpose and use. In this work, we developed a modified algorithm for optimal coalescing that helps a register allocator for an embedded processor to better handle such heterogeneity of the register architecture. In the experiment, an existing register allocator was able to achieve up to 10% reduction in code size through our coalescing, and avoid many spills that would have been generated without our scheme.\",\n \"Title: Register coalescing techniques for heterogeneous register architecture with copy sifting\\nYear: 2009\\n\\nAbstract: Optimistic coalescing has been proven as an elegant and effective technique that provides better chances of safely coloring more registers in register allocation than other coalescing techniques. Its algorithm originally assumes homogeneous registers, which are all gathered in the same register file. Although this register architecture is still common in most general-purpose processors, embedded processors often contain heterogeneous registers, which are scattered in physically different register files dedicated for each dissimilar purpose and use. In this work, we show that optimistic coalescing is also useful for an embedded processor to better handle such heterogeneity of the register architecture, and developed a modified algorithm for optimal coalescing that helps a register allocator. In the experiment, an existing register allocator was able to achieve up to 13.0% reduction in code size through our coalescing, and avoid many spills that would have been generated without our scheme.\",\n \"Title: Improving performance of nested loops on reconfigurable array processors\\nYear: 2012\\n\\nAbstract: Pipelining algorithms are typically concerned with improving only the steady-state performance, or the kernel time. The pipeline setup time happens only once and therefore can be negligible compared to the kernel time. However, for Coarse-Grained Reconfigurable Architectures (CGRAs) used as a coprocessor to a main processor, pipeline setup can take much longer due to the communication delay between the two processors, and can become significant if it is repeated in an outer loop of a loop nest. In this paper we evaluate the overhead of such non-kernel execution times when mapping nested loops for CGRAs, and propose a novel architecture-compiler cooperative scheme to reduce the overhead, while also minimizing the number of extra configurations required. Our experimental results using loops from multimedia and scientific domains demonstrate that our proposed techniques can greatly increase the performance of nested loops by up to 2.87 times compared to the conventional approach of accelerating only the innermost loops. Moreover, the mappings generated by our techniques require only a modest number of configurations that can fit in recent reconfigurable architectures.\",\n \"Title: Management environment of mass windows servers for server-based computing\\nYear: 2009\\n\\nAbstract: Windows Servers for sever-based computing are usually organized with many servers, regardless of the applications. Because more server systems require higher management cost, powerful and easily usable tools are mandatory to manage massive numbers of Windows Servers. In this paper, we present a very flexible management environment that is able to organize and manage massive numbers of Windows Servers. Our management environment is not only flexible in managing Windows Servers with various type of applications but also very powerful so that it can manage more than a thousand of Windows Servers.\",\n \"Title: A proof method for the correctness of modularized 0CFA\\nYear: 2002\\n\\nAbstract: This article is about our Þndings when we tried to derive a modular version from a whole-program control-ßow analysis (CFA). Deriving a modular version from a whole-program kCFA makes the resulting analysis polyvariant at module- level. Hence the correctness of its modularized version cannot be proven in general with respect to the original kCFA. A convenient stepping-stone to prove the cor- rectness of a modularized version is a whole-program kCFA that is polyvariant at module-level. Because CFA is a basis of almost all analyses for higher-order programs, our result can be seen as a general hint of using the module-variant whole-program analysis in order to ease the correctness proof for a modularized version. Our work can also be seen as a formal investigation, for CFA, of the folklore that modularization improves the analysis accuracy.\",\n \"Title: Communication studies of single-threaded and multithreaded distributed-memory machines\\nYear: 1999\\n\\nAbstract: This report explicates the communication overlapping capabilities of three distributed-memory machines, SGI/Cray T3E, IBM SP-2 with wide nodes, and the ETL EM-X. Bitonic sorting and Fast Fourier Transform are selected for experiments. Various message sizes are used to determine when, where, how much and why the overlapping takes place. Experimental results with up to 64 processors indicated that the communication performance of EM-X is insensitive to various message sizes while SP-2 is the most sensitive. T3E stayed in between. The EM-X gave the highest communication overlapping capability while T3E did the lowest. The experimental results are compared with the analytical results based on LogP and LogGP communication models\",\n \"Title: A Comparative Analysis of Dependence Testing Mechanisms\\nYear: 2000\\n\\nAbstract: The internal mechanism used for a dependence test constrains its accuracy and determines its speed. So does the form in which it represents array subscript expressions. The internal mechanism and representational form used for our Access Region Test (ART) is different from that used in any other dependence test, and therefore its constraints and characteristics are likewise different. In this paper, we briefly describe our descriptor for representing memory accesses, the Linear Memory Access Descriptor (LMAD) and the ART. We then describe the LMAD intersection algorithm in some detail. Finally, we compare and contrast the mechanisms of the LMAD intersection algorithm with the internal mechanisms for a number of prior dependence tests.\",\n \"Title: Compiler transformations for effectively exploiting a zero overhead loop buffer\\nYear: 2005\\n\\nAbstract: A Zero Overhead Loop Buffer (ZOLB) is an architectural feature that is commonly found in DSP processors. This buffer can be viewed as a compiler managed cache that contains a sequence of instructions that will be executed a specified number of times without incurring any loop overhead. Unlike loop unrolling, a loop buffer can be used to minimize loop overhead without the penalty of increasing code size. In addition, a ZOLB requires relatively little space and power, which are both important considerations for most DSP applications. This paper describes strategies for generating code to effectively use a ZOLB. We have found that many common code improving transformations used by optimizing compiler on conventional architectures can be easily used to (1) allow more loops to be placed in a ZOLB, (2) further reduce loop overhead of the loops placed in a ZOLB, and (3) avoid redundant loading of ZOLB loops. The results given in this paper demonstrate that this architectural feature can often be exploited with substantial improvements in execution time and slight reductions in code size for various signal processing applications.\",\n \"Title: Code optimizations for a VLIW-style network processing unit\\nYear: 2004\\n\\nAbstract: The explosive growth in network bandwidth and Internet services such as QoS (quality of service) and SLA (service level agreement) monitoring have created the need for new networking hardware called a Network Processing Unit (NPU). In order to rapidly reconfigure the NPU for frequently varying Internet services and technologies, a high-performance C compiler is urgently needed. Several code generation techniques, which are intended to meet the high code quality demands of other types of application specific instructionset processors (ASIPs) like digital signal processors (DSPs), have already been developed. However, these techniques are insufficient for NPUs due to striking architectural differences such as asymmetric data paths. The main purpose of this paper is to discuss our recent experience with the development of a commercial compiler for a new NPU called the Paion PPII, which is basically a packet engine for NPU to meet the growing need for new high-bandwidth communication equipment targeted for Internet routers and ethernet adapters. For this purpose, we will first show the architectural challenges posed by the target NPU. Then, we will describe several compiler techniques that we found to be effective for the target NPU with various unorthogonal architectural features. The current implementations of the PPII use a VLIW (Very Long Instruction Word) architecture. So, we handled this VLIW-style architecture by employing a simple code compaction scheme which packs multiple parallel instructions into one long instruction word. The experimental results show that our techniques are effective for significantly reducing the dynamic instruction count.\",\n \"Title: Dynamic Operands Insertion for VLIW Architecture with a Reduced Bit-width Instruction Set\\nYear: 2012\\n\\nAbstract: Performance, code size and power consumption are all primary concern in embedded systems. To this effect, VLIW architecture has proven to be useful for embedded applications with abundant instruction level parallelism. But due to the long instruction bus width it often consumes more power and memory space than necessary. One way to lessen this problem is to adopt a reduced bit-width instruction set architecture (ISA) that has a narrower instruction word length. This facilitates a more efficient hardware implementation in terms of area and power by decreasing bus-bandwidth requirements and the power dissipation associated with instruction fetches. Also earlier studies reported that it helps to reduce the code size considerably. In practice, however, it is impossible to convert a given ISA fully into an equivalent reduced bit-width one because the narrow instruction word, due to bit-width restrictions, can encode only a small subset of normal instructions in the original ISA. Consequently, existing processors provide narrow instructions in very limited cases along with severe restrictions on register accessibility. The objective of this work is to explore the possibility of complete conversion, as a case study, of an existing 32-bit VLIW ISA into a 16-bit one that supports effectively all 32-bit instructions. To this objective, we attempt to circumvent the bit-width restrictions by dynamically extending the effective instruction word length of the converted 16-bit operations. At compile time when a 32-bit operation is converted to a 16-bit word format, we compute how many bits are additionally needed to represent the whole 32-bit operation and store the bits separately in the VLIW code. Then at run time, these bits are retrieved on demand and inserted to a proper 16-bit operation to reconstruct the original 32-bit representation. According to our experiment, the code size becomes significantly smaller after the conversion to 16-bit VLIW code. Also at a slight run tim- cost, the machine with the 16-bit ISA consumes much less energy than the original machine.\",\n \"Title: A New Addressing Mode For The Encoding Space Problem On Embedded Processors\\nYear: 2009\\n\\nAbstract: The complexity of today's applications increases with various requirements such as execution time, code size or power consumption. To satisfy these requirements for performance, efficient instruction set design is one of the important issues because an instruction customized for specific applications can make better performance than multiple instructions in aspect of fast execution time, decrease of code size, and low power consumption. Limited encoding space, however, does not allow adding application-specific and complex instructions freely to our instruction set architecture. To resolve this problem, conventional architectures increases free space for encoding by trimming excessive bits required beyond the fixed word length. This approach however shows weakness in terms of the complexity of compiler, code size and execution time. In this paper, we propose a new instruction encoding scheme based on the dynamic implied addressing mode (DIAM) to resolve limited encoding space and side-effect by trimming. Our DIAM-based approach uses a special program memory to store extra encoding information. We also suggest a code generation algorithm to fully utilize the DIAM. In our experiment, the architecture augmented with DIAMs shows about 10% code size reduction and speed up on average, as compared to the base architecture without DIAMs.\",\n \"Title: KI-Mon: a hardware-assisted event-triggered monitoring platform for mutable kernel object\\nYear: 2013\\n\\nAbstract: Kernel rootkits undermine the integrity of system by manipulating its operating system kernel. External hardware-based monitors can serve as a root of trust that is resilient to rootkit attacks. The existing external hardware-based approaches lack an event-triggered verification scheme for mutable kernel objects. To address the issue, we present KI-Mon, a hardware-based platform for event-triggered kernel integrity monitor. A refined form of bus traffic monitoring efficiently verifies the update values of the objects, and callback verification routines can be programmed and executed for a designated event space. We have built a KI-Mon prototype to demonstrate the efficacy of KI-Mon's event-triggered mechanism in terms of performance overhead for the monitored host system and the processor usage of the KI-Mon processor.\",\n \"Title: Implementing dynamic implied addressing mode for multi-output instructions\\nYear: 2010\\n\\nAbstract: The ever-increasing demand for faster execution time, smaller resource usage and lower energy consumption has compelled architects of embedded processors to adopt more specialized hardware features with irregular data paths and heterogeneous registers that are customized to the needs of their target applications. These processors consequently provide a rich set of specialized instructions in order to enable programmers to access these features. Such an instruction is typically a multi-output instruction (MOI), which outputs multiple results parallely in order to exploit inherent underlying hardware parallelism. Earlier study has exhibited that MOIs help to enhance performance in aspect of instruction counts and code size. However, as MOIs require more operands, they tend to increase not only the size of the instruction set but also the size of individual instructions. This can be a serious setback for embedded processors, which are mostly subject to strong resource limitations (particularly in this case, limited instruction encoding space). For this reason, these processors are often allowed to include only a very small subset of the total desired MOIs in their instruction sets, despite there can be sufficient silicon real estate to accommodate these specialized MOIs. To attack this problem, we introduce a novel instruction encoding scheme based on the dynamic implied addressing mode (DIAM). In this paper, we will discuss how we have overcome the encoding space problem for our target embedded processor whose instruction set has been augmented with a variety of MOIs. Our DIAM-based encoding scheme employs a small on-chip buffer to supplement extra encoding information for MOIs at run time. The empirical results are promising: the scheme allows us to encode many more MOIs for our processor; thereby helping us to achieve considerable reduction of code size as well as running time after the DIAM is additively implemented in the original architecture.\",\n \"Title: Bypass aware instruction scheduling for register file power reduction\\nYear: 2006\\n\\nAbstract: Since register files suffer from some of the highest power densities within processors, designers have investigated several architectural strategies for register file power reduction, including \\\"On Demand RF Read\\\" where the register file is read only if the operand value is not available from the bypasses. However, we show in this paper that significant additional reductions in the register file power consumption can be obtained by scheduling instructions so that they transfer the operands via bypasses, rather than reading from the register file. Such instruction scheduling requires the compiler to be cognizant of the bypasses in the processor pipeline. In this paper, we develop several bypass aware instruction scheduling heuristics varying in time complexity, and study their effectiveness on the Intel XScale processor pipeline running MiBench benchmarks. Our experimental results show additional power consumption reductions of up to 26% and on average 12% over and above the register file power reduction achieved through existing techniques.\",\n \"Title: Efficient and precise array access analysis\\nYear: 2002\\n\\nAbstract: A number of existing compiler techniques hinge on the analysis of array accesses in a program. The most important task in array access analysis is to collect the information about array accesses of interest and summarize it in some standard form. Traditional forms used in array access analysis are sensitive to the complexity of array subscripts; that is, they are usually quite accurate and efficient for simple array subscripting expressions, but lose accuracy or require potentially expensive algorithms for complex subscripts. Our study has revealed that in many programs, particularly numerical applications, many access patterns are simple in nature even when the subscripting expressions are complex. Based on this analysis, we have developed a new, general array region representational form, called the linear memory access descriptor (LMAD). The key idea of the LMAD is to relate all memory accesses to the linear machine memory rather than to the shape of the logical data structures of a programming language. This form helps us expose the simplicity of the actual patterns of array accesses in memory, which may be hidden by complex array subscript expressions. Our recent experimental studies show that our new representation simplifies array access analysis and, thus, enables efficient and accurate compiler analysis.\",\n \"Title: A code-generator generator for multi-output instructions\\nYear: 2007\\n\\nAbstract: We address the problem of instruction selection for Multi-Output Instructions (MOIs), producing more than one result. Such inherently parallel hardware instructions are very common in the area of Application Specific Instruction Set Processors (ASIPs) and Digital Signal Processors (DSPs) which are frequently used in System-on-Chips as programmable cores. In order to provide high-level programmability, and consequently guarantee widespread acceptance, sophisticated compiler support for these programmable cores is of high importance. Since it is not possible to model Multi-Output Instructions as trees in the compiler's Intermediate Representation (IR), traditional approaches for code selection are not sufficient. Extending traditional code-generation approaches for MOI-selection is essentially a graph covering problem, which is known to be NP-complete. We present a new heuristic algorithm incorporated in a retargetable code-generator generator capable of exploiting arbitrary inherently parallel MOIs. We prove the concept by integrating the tool into the LCC compiler which has been targeted towards different Instruction Set Architectures based on the MIPS architecture. Several network applications as well as some DSP benchmarks were compiled and evaluated to obtain results.\",\n \"Title: Orthogonal Instruction Encoding for a 16-bit Embedded Processor with Dynamic Implied Addressing Mode\\nYear: 2009\\n\\nAbstract: Although 32-bit architectures are becoming the norm for modern microprocessors, 16-bit ones are still employed by many low-end processors, for which small size and low power consumption are of high priority. However, 16-bit architectures have a critical disadvantage for embedded processors that they do not provide enough encoding space to add special instructions coined for certain applications. To overcome this, many existing architectures adopt non-orthogonal, irregular instruction sets to accommodate a variety of unusual addressing modes thru which more opcodes and operands are densely encoded within the narrow instruction word. In general, these non-orthogonal architectures are regarded compiler-unfriendly as they tend to requires extremely sophisticated compiler techniques for optimal code generation. To address this issue, we propose a compiler-friendly processor with a new addressing mode, called the dynamic implied addressing mode (DIAM). In this paper, we will demonstrate that the DIAM provides more encoding space for our 16-bit processor so that we are able to support more instructions specially customized for our applications. And yet, the processor maintains a RISC-style orthogonal architecture, thereby allowing us to use traditional code generation algorithms. In our experiment, the architecture augmented with DIAMs shows 6.2% code size reduction and 3.5% performance increase on average, as compared to the basic architecture without DIAMs.\",\n \"Title: A Quantitative Comparison of Two Retargetable Compilation Approaches.\\nYear: 2003\\n\\nAbstract: In the design of an embedded processor, the compiler design is tightly coupled with the underlying processor architecture, and thus it is crucial to rapidly retarget a compiler along with the change in the architecture in order to expedite the processor design. However, among many compiler writers, there is a controversial issue that has long been argued - whether a compiler can be easily retargetable while it performs sophisticated machine-specific optimizations for a new architecture configuration. This study examines this issue by finding some possible cases where optimizations may be impeded on a pathway to building a retargetable compiler For this, we developed two types of compilation frameworks called user-retargetable and developer-retargetable, and compared their performance.\",\n \"Title: Compiler and microarchitectural approaches for register file thermal management\\nYear: 2012\\n\\nAbstract: Register files are responsible for the majority of thermal emergencies in high performance processors. In this paper, we propose compiler-microarchitecture cooperative techniques to reduce the performance penalty incurred by existing thermal management schemes. Our experiments show that an existing dynamic thermal management (DTM) scheme may result in 47% performance degradation at 45 nm technology node as compared to the ideal case where the processor can sustain any thermal emergency and no DTM is applied. We also evaluate performance degradation of a couple of other DTMs and demonstrate that our cooperative policy can bring down this performance penalty. Our approach shows the consistent effectiveness even with the technology scaling.\",\n \"Title: Fast memory bank assignment for fixed-point digital signal processors\\nYear: 2004\\n\\nAbstract: Most vendors of digital signal processors (DSPs) support a Harvard architecture, which has two or more memory buses, one for program and one or more for data and allow the processor to access multiple words of data from memory in a single instruction cycle. Also, many existing fixed-point DSPs are known to have an irregular architecture with heterogeneous registers, which contains multiple register files that are distributed and dedicated to different sets of instructions. Although there have been several studies conducted to efficiently assign data to multimemory banks, most of them assumed processors with relatively simple, homogeneous general-purpose registers. Thus, several vendor-provided compilers for DSPs that we examined were unable to efficiently assign data to multiple data memory banks, thereby often failing to generate highly optimized code for their machines. As a consequence, programmers for these DSPs often manually assign program variables to memories so as to fully utilize multimemory banks in their code. This paper reports on our recent attempt to address this problem by presenting an algorithm that helps the compiler to efficiently assign data to multimemory banks. Our algorithm differs from previous work in that it assigns variables to memory banks in separate, decoupled code generation phases, instead of a single, tightly coupled phase. The experimental results have revealed that our decoupled algorithm greatly simplifies our code generation process; thus our compiler runs extremely fast, yet generates target code that is comparable in quality to the code generated by a coupled approach.\",\n \"Title: Dynamic code duplication with vulnerability awareness for soft error detection on VLIW architectures\\nYear: 2013\\n\\nAbstract: Soft errors are becoming a critical concern in embedded system designs. Code duplication techniques have been proposed to increase the reliability in multi-issue embedded systems such as VLIW by exploiting empty slots for duplicated instructions. However, they increase code size, another important concern, and ignore vulnerability differences in instructions, causing unnecessary or inefficient protection when selecting instructions to be duplicated under constraints. In this article, we propose a compiler-assisted dynamic code duplication method to minimize the code size overhead, and present vulnerability-aware duplication algorithms to maximize the effectiveness of instruction duplication with least overheads for VLIW architecture. Our experimental results with SoarGen and Synopsys simulation environments demonstrate that our proposals can reduce the code size by up to 40% and detect more soft errors by up to 82% via fault injection experiments over benchmarks from DSPstone and Livermore Loops as compared to the previously proposed instruction duplication technique.\",\n \"Title: Extrax: security extension to extract cache resident information for snoop-based external monitors\\nYear: 2015\\n\\nAbstract: Advent of rootkits has urged researchers to conduct much research on defending the integrity of OS kernels. Even though recently proposed snoop-based monitors have shown to provide higher performance and security level compared to conventional hypervisor-based monitors, we discovered that the use of write-back caches in a system would seriously undermine the effectiveness of snoop-based monitors. To address the problem, we propose a special hardware unit called Extrax which makes use of existing hardware logic, core debugging interface, to extract necessary information for security monitoring. Being implemented to refine the debug information for security purposes, Extrax assists snoop-based monitors to detect attacks that exploit write-back caches. Experimental results show that our system can detect more advanced attacks, which the state-of-the-art snoop-based hardware monitors cannot capture, with moderate area overhead and power consumption.\",\n \"Title: Techniques to Minimize State Transfer Costs for Dynamic Execution Offloading in Mobile Cloud Computing\\nYear: 2014\\n\\nAbstract: In order to meet the increasing demand for high performance in smartphones, recent studies suggested mobile cloud computing techniques that aim to connect the phones to adjacent powerful cloud servers to throw their computational burden to the servers. These techniques often employ execution offloading schemes that migrate a process between machines during its execution. In execution offloading, code regions to be executed on the server are decided statically or dynamically based on the complex analysis on execution time and process state transfer costs of every region. Expectedly, the transfer cost is a deciding factor for the success of execution offloading. According to our analysis, it is dominated by the total size of heap objects transferred over the network. But previous work did not try hard to minimize this size. Thus in this paper, we introduce novel techniques based on compiler code analysis that effectively reduce the transferred data size by transferring only the essential heap objects and the stack frames actually referenced in the server. The experiments exhibit that the reduced size positively influences not only the transfer time itself but also the overall effectiveness of execution offloading, and ultimately, improves the performance of our mobile cloud computing significantly in terms of execution time and energy consumption.\",\n \"Title: CMcloud: Cloud Platform for Cost-Effective Offloading of Mobile Applications\\nYear: 2014\\n\\nAbstract: Recent efforts towards mobile cloud propose to offload mobile applications to cloud servers for the improved performance and battery life of mobile devices. However, existing schemes completely ignore the costs of cloud resources by assuming that idle servers are always available for free of charge. These unrealistic assumptions make each server run only a small load to achieve the guaranteed high offload performance. Therefore, these schemes cannot be applied to real-world commercial clouds which aim to minimize the operation costs by maximizing the server throughput, and then charge users for their resource usage. In this paper, we propose CMcloud, a novel cost-effective mobile-to-cloud offloading platform, which works nicely under the real-world cloud environments. CMcloud minimizes both the server costs and the user service fee by offloading as many mobile applications to a single server as possible, while satisfying the target performance of all applications. To achieve such goals, CMcloud exploits novel architecture performance modeling and server migration techniques. Our implementation shows that CMcloud can improve the data enter throughput by 84% over a conventional static light-load scheme (or a 2.7x higher per-socket throughput.) Alternatively, CMcloud reduces the number of service failures by 83% over a static high-load scheme, while even improving the throughput by 31%.\",\n \"Title: Software-Based Selective Validation Techniques for Robust CGRAs Against Soft Errors.\\nYear: 2016\\n\\nAbstract: Coarse-Grained Reconfigurable Architectures (CGRAs) are drawing significant attention since they promise both performances with parallelism and flexibility with reconfiguration. Soft errors (or transient faults) are becoming a serious design concern in embedded systems including CGRAs since the soft error rate is increasing exponentially as technology is scaling. A recently proposed software-based technique with TMR (Triple Modular Redundancy) implemented on CGRAs incurs extreme overheads in terms of runtime and energy consumption mainly due to expensive voting mechanisms for the outputs from the triplication of every operation. In this article, we propose selective validation mechanisms for efficient modular redundancy techniques in the datapaths on CGRAs. Our techniques selectively validate the results at synchronous operations rather than every operation in order to reduce the expensive performance overhead from the validation mechanism. We also present an optimization technique to further improve the runtime and the energy consumption by minimizing synchronous operations where a validating mechanism needs to be applied. Our experimental results demonstrate that our selective validation-based TMR technique with our optimization on CGRAs can improve the runtime by 41.0p and the energy consumption by 26.2p on average over benchmarks as compared to the recently proposed software-based TMR technique with the full validation.\",\n \"Title: Implementing an Application-Specific Instruction-Set Processor for System-Level Dynamic Program Analysis Engines\\nYear: 2015\\n\\nAbstract: In recent years, dynamic program analysis (DPA) has been widely used in various fields such as profiling, finding bugs, and security. However, existing solutions have their own weaknesses. Software solutions provide flexibility in DPA but they suffer from tremendous performance overhead. In contrast, core-level hardware engines rely on specialized integrated logics and attain extremely fast computation, but they have a limited functional extensibility because the logics are tightly coupled with the host processor. To mend this, a prior system-level approach utilizes an existing channel to integrate their hardware without necessitating the host architecture modification and introduced great potential in performance. Nevertheless, the prior work does not address the detailed design and implementation of the engine, which is quite essential to leverage the deployment on real systems. To address this, in this article, we propose an implementation of programmable DPA hardware engine, called program analysis unit (PAU). PAU is an application-specific instruction-set processor (ASIP) whose instruction set is customized to reflect common features of various DPA methods. With the specialized architecture and programmability of software, our PAU aims at fast computation and sufficient flexibility. In our case studies on several DPA techniques, we show that our ASIP approach can be successfully applicable to complex DPA schemes while providing hardware-backed power in performance and software-based flexibility in analysis. Recent experiments on our FPGA prototype revealed that the performance of PAU is 4.7-13.6 times faster than pure software DPA, and the power/area consumption is also acceptably small compared to today's mobile processors.\",\n \"Title: Efficient dynamic information flow tracking on a processor with core debug interface\\nYear: 2015\\n\\nAbstract: Dynamic information flow tracking (DIFT) is a promising solution to prevent various attacks on software running on a processor. Previous hardware solutions usually mandate drastic change to internal processor architecture. More recent ones to minimize the change have proposed external devices for DIFT. However, these approaches intrinsically suffer from the high overhead to communicate with their external devices. Consequently, they either significantly lose performance, or inevitably make invasive modifications to the processor inside. Our solution also rely on external hardware for DIFT, but unlike theirs, ours exploits the core debug interface (CDI) to tackle the communication issue. CDI is provided in most commercial processors for debugging so that we were able to build our system simply by plugging our hardware to the processor via CDI, precluding the need for altering the processor itself. Experiments show that our hardware efficiently performs DIFT mainly thanks to the support of CDI that helps us cut substantially down the communication costs.\",\n \"Title: Accelerating bootstrapping in FHEW using GPUs\\nYear: 2015\\n\\nAbstract: Recently, the usage of GPU is not limited to the jobs associated with graphics and a wide variety of applications take advantage of the flexibility of GPUs to accelerate the computing performance. Among them, one of the most emerging applications is the fully homomorphic encryption (FHE) scheme, which enables arbitrary computations on encrypted data. Despite much research effort, it cannot be considered as practical due to the enormous amount of computations, especially in the bootstrapping procedure. In this paper, we accelerate the performance of the recently suggested fast bootstrapping method in FHEW scheme using GPUs, as a case study of a FHE scheme. In order to optimize, we explored the reference code and carried out profiling to find out candidates for performance acceleration. Based on the profiling results, combined with more flexible tradeoff method, we optimized the bootstrapping algorithm in FHEW using GPU and CUDA's programming model. The empirical result shows that the bootstrapping of FHEW ciphertext can be done in less than 0.11 second after optimization.\",\n \"Title: Towards a practical solution to detect code reuse attacks on ARM mobile devices\\nYear: 2015\\n\\nAbstract: In recent years, there is a growing need to protect security and privacy of the data against various attacks on software running on smart mobile devices. The attackers mostly attempt to acquire privileges to control system behaviors as they want. As of today, the code reuse attack (CRA) is known as one of the most sophisticated techniques that can be exploited in such attempts. The attackers launch CRAs to perform arbitrary computation by reusing and chaining existing code fragments, called gadgets. Prior solutions to CRAs are engineered either in software or hardware. However, both of them have their own weaknesses. Software solutions suffer from huge performance overhead because they occupy computing resources of the host CPU. On the other hand, existing hardware solutions all require invasive modifications to the CPU internal architecture. This is contradictory to the conventional application processor (AP) design principle which is to integrate off-the-shelf commodity CPU cores and other special-purpose hardware modules together to form a system. In this paper, we propose a more practical hardware solution which conforms to such design convention, thus being amenable for immediate deployment to modern mobile devices that use APs as their central computing engines. In our work, we target the devices that employ as their AP CPUs the ARM processors which are the de-facto standard CPUs for commercial mobile devices today. The key difference of ours from previous hardware solutions is that our CRA detection hardware modules have been integrated as off-core modules with the processor, strictly following the AP designing principle. We exploit the ARM debug interface to obtain the core internal information which is not directly accessible from off-core hardware modules. As a result, we were able to detect CRAs from outside the CPU without modifying the processor internal. For our preliminary experiment, we have implemented in our prototype a module to detect the attacks based on return-oriented programming (ROP) which is a representative technique used in CRAs. Empirical results show that our solution successfully detects ROP attacks with negligibly low runtime overhead and moderate area overhead.\",\n \"Title: Energy-Reduction Offloading Technique for Streaming Media Servers.\\nYear: 2016\\n\\nAbstract: Recent growth in popularity of mobile video services raises a demand for one of the most popular and convenient methods of delivering multimedia data, video streaming. However, heterogeneity of currently existing mobile devices involves an issue of separate video transcoding for each type of mobile devices such as smartphones, tablet PCs, and smart TVs. As a result additional burden comes to media servers, which pretranscode multimedia data for number of clients. Regarding even higher increase of video data in the Internet in the future, the problem of media servers overload is impending. To struggle against the problem an offloading method is introduced in this paper. By the use of SorTube offloading framework video transcoding process is shifted from the centralized media server to the local offloading server. Thus, clients can receive personally customized video stream; meanwhile the overload of centralized servers is reduced.\",\n \"Title: Architectural Supports to Protect OS Kernels from Code-Injection Attacks.\\nYear: 2016\\n\\nAbstract: The kernel code injection is a common behavior of kernel -compromising attacks where the attackers aim to gain their goals by manipulating an OS kernel. Several security mechanisms have been proposed to mitigate such threats, but they all suffer from non-negligible performance overhead. This paper introduces a hardware reference monitor, called Kargos, which can detect the kernel code injection attacks with nearly zero performance cost. Kargos monitors the behaviors of an OS kernel from outside the CPU through the standard bus interconnect and debug interface available with most major microprocessors. By watching the execution traces and memory access events in the monitored target system, Kargos uncovers attempts to execute malicious code with the kernel privilege. According to our experiments, Kargos detected all the kernel code injection attacks that we tested, yet just increasing the computational loads on the target CPU by less than 1% on average.\",\n \"Title: Hardware-Assisted On-Demand Hypervisor Activation for Efficient Security Critical Code Execution on Mobile Devices.\\nYear: 2016\\n\\nAbstract: As more and more mobile applications need to run security critical codes (SCCs) for secure transactions and critical information handling, the demand for a Trusted Execution Environment (TEE) to ensure safe execution of SCCs is rapidly escalating. Although a number of studies have implemented TEEs using TrustZone or hypervisors and have evinced the effectiveness in terms of security, they face major challenges when considering deployment in mobile devices. TrustZone-based approaches bloat the TCB of the system as they must increase the code base size of the most privileged software. Hypervisor-based approaches incur performance overhead on mobile devices that are already suffering from resource restrictions. To alleviate these problems, in this paper, we propose a hybrid approach that utilizes both TrustZone and a hypervisor. Our approach basically implements a TEE using a hypervisor, while mitigating performance overhead by activating the hypervisor only when the TEE is demanded by SCCs. This scheme, called on-demand hypervisor activation, has been efficiently and securely implemented by leveraging the memory protection capability of TrustZone. We have implemented and experimented our system with real world applications. The results show that our system can successfully protect SCCs without any noticeable delay (< 100 µs), while limiting the overhead increase due to our hypervisor during its hibernation near 0 %.\",\n \"Title: HDFI: Hardware-Assisted Data-Flow Isolation\\nYear: 2016\\n\\nAbstract: Memory corruption vulnerabilities are the root cause of many modern attacks. Existing defense mechanisms are inadequate; in general, the software-based approaches are not efficient and the hardware-based approaches are not flexible. In this paper, we present hardware-assisted data-flow isolation, or, HDFI, a new fine-grained data isolation mechanism that is broadly applicable and very efficient. HDFI enforces isolation at the machine word granularity by virtually extending each memory unit with an additional tag that is defined by dataflow. This capability allows HDFI to enforce a variety of security models such as the Biba Integrity Model and the Bell -- LaPadula Model. We implemented HDFI by extending the RISC-V instruction set architecture (ISA) and instantiating it on the Xilinx Zynq ZC706 evaluation board. We ran several benchmarks including the SPEC CINT 2000 benchmark suite. Evaluation results show that the performance overhead caused by our modification to the hardware is low (<; 2%). We also developed or ported several security mechanisms to leverage HDFI, including stack protection, standard library enhancement, virtual function table protection, code pointer protection, kernel data protection, and information leak prevention. Our results show that HDFI is easy to use, imposes low performance overhead, and allows us to create more elegant and more secure solutions.\",\n \"Title: Integration of ROP/JOP monitoring IPs in an ARM-based SoC\\nYear: 2016\\n\\nAbstract: Code reuse attack (CRA) is a powerful technique that allows attackers to perform arbitrary computation by reusing the existing code fragments. To defend from CRAs while complying with the conventional ARM-based SoC design principles, the previous hardware solution suggests the use of the ARM debug interface to acquire the control flow information of an application running on the host. However, it requires tremendous storage space to store the complementary data necessary to trace the execution flow. In this paper, we propose a new hardware CRA monitor which gives both low storage overhead and high performance. For this, we have used an instrumentation technique which transforms the original ARM binary code into a form which will ease the CRA monitor to efficiently extract through the debug interface all crucial pieces of runtime information from the trace outcomes. In addition, while the previous solution was only built to detect one type of CRAs, called return-oriented programming (ROP), ours has been designed to unify the detection logics for ROP and another important type of CRAs, called jump-oriented programming (JOP). Empirical results show that our solution dramatically reduces the storage overhead for CRA detection, yet successfully detecting both ROP and JOP attacks simultaneously with negligibly low runtime overhead and moderate area overhead.\",\n \"Title: A hardware-based technique for efficient implicit information flow tracking.\\nYear: 2016\\n\\nAbstract: To access sensitive information, some recent advanced attacks have been successful in exploiting implicit flows in a program in which sensitive data affects the control path and in turn affects other data. To track the sensitive data through implicit flows, several software and hardware based approaches have been proposed, but they suffer from the non-negligible performance overhead. In this paper, we propose a hardware tracking engine for implicit flow, called the implicit flow tracking unit (IFTU). By adopting the tracking scheme for implicit flow and mapping it to the specialized hardware, our solution can efficiently perform the implicit flow tracking with reasonable area costs.\",\n \"Title: LSTM-Based System-Call Language Modeling and Robust Ensemble Method for Designing Host-Based Intrusion Detection Systems.\\nYear: 2016\\n\\nAbstract: In computer security, designing a robust intrusion detection system is one of the most fundamental and important problems. In this paper, we propose a system-call language-modeling approach for designing anomaly-based host intrusion detection systems. To remedy the issue of high false-alarm rates commonly arising in conventional methods, we employ a novel ensemble method that blends multiple thresholding classifiers into a single one, making it possible to accumulate u0027highly normalu0027 sequences. The proposed system-call language model has various advantages leveraged by the fact that it can learn the semantic meaning and interactions of each system call that existing methods cannot effectively consider. Through diverse experiments on public benchmark datasets, we demonstrate the validity and effectiveness of the proposed method. Moreover, we show that our model possesses high portability, which is one of the key aspects of realizing successful intrusion detection systems.\",\n \"Title: Efficient Security Monitoring with the Core Debug Interface in an Embedded Processor.\\nYear: 2016\\n\\nAbstract: For decades, various concepts in security monitoring have been proposed. In principle, they all in common in regard to the monitoring of the execution behavior of a program (e.g., control-flow or dataflow) running on the machine to find symptoms of attacks. Among the proposed monitoring schemes, software-based ones are known for their adaptability on the commercial products, but there have been concerns that they may suffer from nonnegligible runtime overhead. On the other hand, hardware-based solutions are recognized for their high performance. However, most of them have an inherent problem in that they usually mandate drastic changes to the internal processor architecture. More recent ones have strived to minimize such modifications by employing external hardware security monitors in the system. However, these approaches intrinsically suffer from the overhead caused by communication between the host and the external monitor. Our solution also relies on external hardware for security monitoring, but unlike the others, ours tackles the communication overhead by using the core debug interface (CDI), which is readily available in most commercial processors for debugging. We build our system simply by plugging our monitoring hardware into the processor via CDI, precluding the need for altering the processor internals. To validate the effectiveness of our approach, we implement two well-known monitoring techniques on our proposed framework: dynamic information flow tracking and branch regulation. The experimental results on our FPGA prototype show that our external hardware monitors efficiently perform monitoring tasks with negligible performance overhead, mainly with thanks to the support of CDI, which helps us reduce communication costs substantially.\",\n \"Title: Optimization techniques to enable execution offloading for 3D video games.\\nYear: 2017\\n\\nAbstract: Nowadays, mobile devices are becoming the most popular computing device as their computing capabilities increase rapidly. However, it is still challenging to execute highly sophisticated applications such as 3D video games on mobile devices due to its constrained key computational resources. Execution offloading approaches have been proposed to resolve this problem by strengthening mobile devices with powerful cloud. Unfortunately, the existing offloading approaches are not suitable for 3D video games because of the unique execution characteristics of them. In this paper, we propose a streaming-based execution offloading framework to enable execution offloading for 3D video games. The experiments show that our framework successfully guarantees 20 frames per second for our benchmark.\",\n \"Title: Using CoreSight PTM to Integrate CRA Monitoring IPs in an ARM-Based SoC.\\nYear: 2017\\n\\nAbstract: The ARM CoreSight Program Trace Macrocell (PTM) has been widely deployed in recent ARM processors for real-time debugging and tracing of software. Using PTM, the external debugger can extract execution behaviors of applications running on an ARM processor. Recently, some researchers have been using this feature for other purposes, such as fault-tolerant computation and security monitoring. This motivated us to develop an external security monitor that can detect control hijacking attacks, of which the goal is to maliciously manipulate the control flow of victim applications at an attacker’s disposal. This article focuses on detecting a special type of attack called code reuse attacks (CRA), which use a recently introduced technique that allows attackers to perform arbitrary computation without injecting their code by reusing only existing code fragments. Our external monitor is attached to the outside of the host system via the system bus and ARM CoreSight PTM, and is fed with execution traces of a victim application running on the host. As a majority of CRAs violates the normal execution behaviors of a program, our monitor constantly watches and analyzes the execution traces of the victim application and detects a symptom of attacks when the execution behaviors violate certain rules that normal applications are known to adhere. We present two different implementations for this purpose: a hardware-based solution in which all CRA detection components are implemented in hardware, and a hardware/software mixed solution that can be employed in a more resource-constrained environment where the deployment of full hardware-level CRA detection is burdensome.\",\n \"Title: Instruction-Level Data Isolation for the Kernel on ARM.\\nYear: 2017\\n\\nAbstract: As more sophisticated services are increasingly offered by the OS kernel on mobile devices, the security and sensitivity of kernel data that they depend on are becoming a critical issue. Data isolation has emerged as a key technique that can address the issue by providing strong protection for sensitive kernel data. However, existing data isolation mechanisms for mobile devices all incur non-negligible performance overhead. We deem that such computational burden would be a serious problem for mobile devices which already suffer from resource poverty. To alleviate this problem, we have developed a new mechanism that enforces data isolation very efficiently on ARM-based machines backed by unique hardware instructions. For evaluation, this instruction-level data isolation mechanism has been implemented in the Android/Linux kernel running on ARM. According to the experiment, it provides a lightweight data isolation capability for security services installed in the kernel.\",\n \"Title: Architectural Supports to Protect OS Kernels from Code-Injection Attacks and Their Applications.\\nYear: 2017\\n\\nAbstract: The kernel code injection is a common behavior of kernel-compromising attacks where the attackers aim to gain their goals by manipulating an OS kernel. Several security mechanisms have been proposed to mitigate such threats, but they all suffer from non-negligible performance overhead. This article introduces a hardware reference monitor, called Kargos, which can detect the kernel code injection attacks with nearly zero performance cost. Kargos monitors the behaviors of an OS kernel from outside the CPU through the standard bus interconnect and debug interface available with most major microprocessors. By watching the execution traces and memory access events in the monitored target system, Kargos uncovers attempts to execute malicious code with the kernel privilege. On top of this, we also applied the architectural supports for Kargos to the detection of ROP attacks. KS-Stack is the hardware component that builds and maintains the shadow stacks using the existing supports to detect this ROP attacks. According to our experiments, Kargos detected all the kernel code injection attacks that we tested, yet just increasing the computational loads on the target CPU by less than 1% on average. The performance overhead of the KS-Stack was also less than 1%.\",\n \"Title: Extended Abstract: Mimicry Resilient Program Behavior Modeling with LSTM based Branch Models.\\nYear: 2018\\n\\nAbstract: In the software design, protecting a computer system from a plethora of software attacks or malware in the wild has been increasingly important. One branch of research to detect the existence of attacks or malware, there has been much work focused on modeling the runtime behavior of a program. Stemming from the seminal work of Forrest et al., one of the main tools to model program behavior is system call sequences. Unfortunately, however, since mimicry attacks were proposed, program behavior models based solely on system call sequences could no longer ensure the security of systems and require additional information that comes with its own drawbacks. In this paper, we report our preliminary findings in our research to build a mimicry resilient program behavior model that has lesser drawbacks. We employ branch sequences to harden our program behavior model against mimicry attacks while employing hardware features for efficient extraction of such branch information during program runtime. In order to handle the large scale of branch sequences, we also employ LSTM, the de facto standard in deep learning based sequence modeling and report our preliminary experiments on its interaction with program branch sequences.\",\n \"Title: A dynamic per-context verification of kernel address integrity from external monitors.\\nYear: 2018\\n\\nAbstract: The introduction of Address Translation Redirection Attack (ATRA) has revealed a critical weakness in all existing hardware-based external kernel integrity monitors. The attack redefines system's memory mappings in favor of the attacker so that the monitored kernel regions are relocated out of the monitor's sight. We provide a generalized approach and a prototype evaluation to prove our proposed scheme for ensuring the integrity of kernel address mapping from external monitors.\",\n \"Title: Design of a Generic Security Interface for RISC-V Processors and its Applications\\nYear: 2018\\n\\nAbstract: In this paper, we propose the design of a generic security interface for RISC-V. This interface increases flexibility of security modules by creating an environment that can operate independently on a host processor. We also present an application using this interface for the memory protection. To check the feasibility of our idea, we implement an early prototype where a RISC-V processor is connected with the proposed hardware components using our interface. The empirical results show that our security interface has enabled a security module operated independently of the processor with no performance and low area overhead.\",\n \"Title: Safe and Efficient Implementation of a Security System on ARM using Intra-level Privilege Separation\\nYear: 2019\\n\\nAbstract: Security monitoring has long been considered as a fundamental mechanism to mitigate the damage of a security attack. Recently, intra-level security systems have been proposed that can efficiently and securely monitor system software without any involvement of more privileged entity. Unfortunately, there exists no full intra-level security system that can universally operate at any privilege level on ARM. However, as malware and attacks increase against virtually every level of privileged software including an OS, a hypervisor, and even the highest privileged software armored by TrustZone, we have been motivated to develop an intra-level security system, named Hilps. Hilps realizes true intra-level scheme in all these levels of privileged software on ARM by elaborately exploiting a new hardware feature of ARM’s latest 64-bit architecture, called TxSZ, that enables elastic adjustment of the accessible virtual address range. Furthermore, Hilps newly supports the sandbox mechanism that provides security tools with individually isolated execution environments, thereby minimizing security threats from untrusted security tools. We have implemented a prototype of Hilps on a real machine. The experimental results demonstrate that Hilps is quite promising for practical use in real deployments.\",\n \"Title: KI-Mon ARM: A Hardware-Assisted Event-triggered Monitoring Platform for Mutable Kernel Object\\nYear: 2019\\n\\nAbstract: External hardware-based kernel integrity monitors have been proposed to mitigate kernel-level malwares. However, the existing external approaches have been limited to monitoring the static regions of kernel while the latest rootkits manipulate the dynamic kernel objects. To address the issue, we present KI-Mon, a hardware-based platform that introduces event-triggered monitoring techniques for kernel dynamic objects. KI-Mon advances the bus traffic snooping technique to not only detect memory write traffic on the host bus but also filter out all but meaningful traffic to generate events. We show how kernel invariant verification software can be developed around these events, and also provide a set of APIs for additional invariant verification development. We also report our findings and considerations on the unique challenges for external monitors – such as cache coherency, dynamic object tracing. We introduce host-side kernel changes that alleviate these issues that involve changes in kernel's object allocation and cache policy control. We have built a prototype of KI-Mon on the ARM architecture to demonstrate the efficacy of KI-Mon's event-triggered mechanism in terms of performance overhead for the monitored host system and the processor usage of the KI-Mon processor.\",\n \"Title: DADE: a fast data anomaly detection engine for kernel integrity monitoring\\nYear: 2019\\n\\nAbstract: In computer systems, ensuring the integrity of the kernel assumes importance as attacks against the kernel allow an adversary to obtain the highest privilege within a compromised system. For this task, typically, an external monitor would perform memory introspection and verify the integrity of kernel data by checking whether certain integrity specifications hold or not. These specifications were commonly written by hand in the past. However, as adversaries turned their eyes to attacking a system through non-control kernel data, the need arose for verifying non-control kernel data, which is, unfortunately, nontrivial to do manually. Acknowledging this, Baliga et al. (Computer security applications conference, 2008. ACSAC 2008. Annual. IEEE, 2008) suggested a framework leveraging machine learning to generate integrity specifications. This generated specifications for both control and non-control data across the entire kernel with little human involvement. Unfortunately, there is a problem in the original design of this framework in regard to its practicality for deployment in real-world systems. In this paper, we propose a new design that accelerates the overall introspection process by virtually eliminating the booting delay that was needed in prior work. To evaluate the effectiveness of our design, we have implemented a prototype engine DADE and found that it only induces a delay of 68.49 ms with each reboot and a delay of 900 ms for an initial scan and an average of 160 ms for subsequent scans.\",\n \"Title: Developing a custom DSP for vision based human computer interaction applications.\\nYear: 2018\\n\\nAbstract: As the computing power of modern devices become greater, computer vision is increasingly adopted as the means of human-computer interaction. The industry is struggling hard to bring computer vision into the mobile domain, but there are some difficulties mainly due to the computationally expansive nature of vision applications. On the other hand, there are various kinds of vision applications, which means using fixed hardware block will meet the performance criteria, but it will be possible to run only one application. To meet our needs, we can use another programmable component that is specialized for parallel processing and has domain specific instructions. In this paper, we introduce our work on the development of a low-power VLIW processor with vision-application specific parallel computation logic and a set of application-specific instructions, to improve the processor’s performance while reducing the power consumption. Our VLIW processor accelerates by adding special instructions on the application’s specific part in which processes heavy computation. We introduce our work on developing a custom DSP for vision system that includes designing the processor with Synopsys Processor Designer tool, and porting LLVM compiler. As the target, we ported a hand recognition application to our system, which we have constructed on Xilinx Zynq evaluation board. Even though our DSP was run at much lower frequency, it could run compute intensive part of the application four times faster than ARM processor, greatly speeding up the whole application.\",\n \"Title: Riskim: Toward Complete Kernel Protection With Hardware Support\\nYear: 2019\\n\\nAbstract: The OS kernel is typically the assumed trusted computing base in a system. Consequently, when they try to protect the kernel, developers often build their solutions in a separate secure execution environment externally located and protected by special hardware. Due to limited visibility into the host system, the external solutions basically all entail the semantic gap problem which can be easily exploited by an adversary to circumvent them. Thus, for complete kernel protection against such adversarial exploits, previous solutions resorted to aggressive techniques that usually come with various adverse side effects, such as high performance overhead, kernel code modifications and/or excessively complicated hardware designs. In this paper, we introduce RiskiM, our new hardware-based monitoring platform to ensure kernel integrity from outside the host system. To overcome the semantic gap problem, we have devised a hardware interface architecture, called PEMI, by which RiskiM is supplied with all internal states of the host system essential for fulfilling its monitoring task to protect the kernel even in the presence of attacks exploiting the semantic gap between the host and RiskiM. To empirically validate the security strength and performance of our monitoring platform in existing systems, we have fully implemented RiskiM in a RISCV system. Our experiments show that RiskiM succeeds in the host kernel protection by detecting even the advanced attacks which could circumvent previous solutions, yet suffering from virtually no aforementioned side effects.\",\n \"Title: Real-Time Anomalous Branch Behavior Inference With A Gpu-Inspired Engine For Machine Learning Models\\nYear: 2019\\n\\nAbstract: Attacks on embedded devices are likely to occur any time in unexpected manners. Thus, the defense systems based on fixed sets of rules will easily be subverted by such unexpected, unknown attacks. Learning-based anomaly detection may potentially prevent new unknown zero-day attacks by leveraging the capability of machine learning (ML) to learn the intricate true nature of software hidden within raw information. This paper introduces our work to develop an MPSoC, called RTAD, which can efficiently support in hardware various ML models that run to detect anomalous behaviors on embedded devices in a real-time fashion, and thus enable the devices to counteract the anomalies in the field. In the IoT era, the importance of security for embedded devices cannot be exaggerated because they will become an enticing target for adversaries as they are being integrated into everyday life to provide users with various services. The above-mentioned potential of learning-based detection is believed to benefit those deployed devices under attacks occurring any time during their field operations in unexpected manners. We hereby assume that ML models are trained with runtime branch information as their data features since a sequence of branches serves as a record of control flow transfers during program execution. In fact, there have been numerous ML studies that examine various types of branches in order to infer (or detect) anomaly in branch behaviors that may be induced by diverse attacks that can cause deviant control flow in software. Our goal of real-time anomalous branch behavior inference poses two challenges to our development of RTAD. Firstly, RTAD must collect and transfer in a timely fashion a sequence of branches as the input to the ML model. Secondly, RTAD must be able to promptly process the delivered branch data with the ML model. To tackle these challenges, we have implemented in RTAD two core components: an input generation module and a GPU-inspired ML processing engine. According to our experiments, RTAD enables various ML models to infer anomaly instantly after the victim program behaves aberrantly as the result of attacks being injected into the system.\",\n \"Title: Learn2Evade: Learning-Based Generative Model for Evading PDF Malware Classifiers\\nYear: 2021\\n\\nAbstract: Recent research has shown that a small perturbation to an input may forcibly change the prediction of a machine learning (ML) model. Such variants are commonly referred to as adversarial examples. Early studies have focused mostly on ML models for image processing and expanded to other applications, including those for malware classification. In this article, we focus on the probl...\",\n \"Title: Data Embedding Scheme for Efficient Program Behavior Modeling With Neural Networks\\nYear: 2022\\n\\nAbstract: As modern programs grow in size and complexity, the importance of program behavior modeling is emerging in various areas. Because of the large amount of data generated by a target program and the difficulty of runtime analysis, previous works in these areas employ deep learning. However, they did not sufficiently consider the input of a target program, since, in our view, program behavior is a history of computational steps consisting of a function and its input arguments. A naive, intuitive way to embed the value of \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"><tex-math notation=\\\"LaTeX\\\">$x$</tex-math></inline-formula>\\n as it is in a vector representation creates a tremendously large vector size. Instead, we found that all the values inducing the same runtime behavior can be represented as one identical \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">characteristic value</i>\\n (CV). In this paper, we show that not only can a \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">characteristic value</i>\\n sequence replace the argument input, but it is also efficient to use it as an input vector for a neural network. This efficiency comes from modeling the whole program with multiple LSTM-RNN models and reducing the input space of the neural network. To demonstrate the effectiveness of this replacement, we performed experiments on the problem of program behavior anomaly detection. Our results show that our model achieves better detection performance compared to previous models and similar detection performance even with smaller model sizes. We also provide a visualization of the embedded vectors extracted from the embedding layer in the neural network model to prove that the CV sequence well represents the arguments.\",\n \"Title: XTENSTORE: Fast Shielded In-memory Key-Value Store on a Hybrid x86-FPGA System\\nYear: 2022\\n\\nAbstract: We propose XTENSTORE, a system that extends the existing SGX-based secure in-memory key-value store with an external hardware accelerator in order to ensure comparable security guarantees with lower performance degradation. The accelerator is implemented on a commodity FPGA card that is readily connected with the x86 CPU via PCIe interconnect to form a hybrid x86-FPGA system. In comparison to the prior SGX-based work, XTENSTORE improves the throughput by 4-33x, and exhibits considerably shorter tail latency (>23x, 99th-percentile).\",\n \"Title: Precise Extraction of Deep Learning Models via Side-Channel Attacks on Edge/Endpoint Devices\\nYear: 2022\\n\\nAbstract: With growing popularity, deep learning (DL) models are becoming larger-scale, and only the companies with vast training datasets and immense computing power can manage their business serving such large models. Most of those DL models are proprietary to the companies who thus strive to keep their private models safe from the model extraction attack (MEA), whose aim is to steal the model by training surrogate models. Nowadays, companies are inclined to offload the models from central servers to edge/endpoint devices. As revealed in the latest studies, adversaries exploit this opportunity as new attack vectors to launch side-channel attack (SCA) on the device running victim model and obtain various pieces of the model information, such as the model architecture (MA) and image dimension (ID). Our work provides a comprehensive understanding of such a relationship for the first time and would benefit future MEA studies in both offensive and defensive sides in that they may learn which pieces of information exposed by SCA are more important than the others. Our analysis additionally reveals that by grasping the victim model information from SCA, MEA can get highly effective and successful even without any prior knowledge of the model. Finally, to evince the practicality of our analysis results, we empirically apply SCA, and subsequently, carry out MEA under realistic threat assumptions. The results show up to 5.8 times better performance than when the adversary has no model information about the victim model.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":98,"string":"98"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13364,"string":"13,364"}}},{"rowIdx":13365,"cells":{"question_id":{"kind":"string","value":"Wu Hua Chen"},"question":{"kind":"string","value":"Generate an abstract for the title \"Hybrid L1×l1-gain analysis of T-S fuzzy positive impulsive systems\" using the following items: 1. Hybrid L1×l1-gain\n2. T-S fuzzy positive impulsive systems \n3. Copositive Lyapunov functions \n4. Exponential stability \n5."},"answer":{"kind":"string","value":"The finite hybrid L1×l1-gain problem for T-S fuzzy positive impulsive systems is proposed. The problem is solved in the framework of discretized copositive Lyapunov functions. In order to highlight the effect of interaction between continuous and discrete dynamics on system performance, both the impulse state and the discrete-time input are included in the introduced copositive Lyapunov functions. By selecting appropriate auxiliary functions for adjusting the variation of copositive Lyapunov function at impulse instants, the introduced copositive Lyapunov functions turn out to be continuous along the solutions of the system. Through employing the novel discretized function, new criteria for exponential stability and finite hybrid L1×l1-gain are derived in terms of finite linear programming. Numerical examples show that the new criteria can achieve higher accuracy than those of the existing ones."},"correct_answer":{"kind":"string","value":"The finite hybrid L1×l1-gain problem for T-S fuzzy positive impulsive systems is proposed. The problem is solved in the framework of discretized copositive Lyapunov functions. In order to highlight the effect of interaction between continuous and discrete dynamics on system performance, both the impulse state and the discrete-time input are included in the introduced copositive Lyapunov functions. By selecting appropriate auxiliary functions for adjusting the variation of copositive Lyapunov function at impulse instants, the introduced copositive Lyapunov functions turn out to be continuous along the solutions of the system. Through employing the novel discretized function, new criteria for exponential stability and finite hybrid L1×l1-gain are derived in terms of finite linear programming. Numerical examples show that the new criteria can achieve higher accuracy than those of the existing ones."},"documents":{"kind":"list like","value":["Title: Delay-dependent exponential stability of uncertain stochastic systems with multiple delays: an LMI approach\nYear: 2005\n\nAbstract: In this paper, the problem of exponential stability in mean square for stochastic systems with multiple delays is investigated. A delay-dependent sufficient condition is derived in terms of linear matrix inequalities (LMIs) by using a descriptor model transformation of the system and by applying Moon's inequality for bounding cross terms. The criteria obtained in this paper can be tested numerically very efficiently using interior point algorithms. An example shows that the proposed methods are less conservative than the other methods.","Title: Robust Stability of Singularly Perturbed Impulsive Systems Under Nonlinear Perturbation.\nYear: 2013\n\nAbstract: The robust stability problem for singularly perturbed impulsive systems under nonlinear perturbation is considered. The uncertainties are assumed to be limited by their upper norm bound. By applying the vector Lyapunov function method and a two-time scale comparison principle, a sufficient condition that ensures robust exponential stability for sufficiently small singular perturbation parameter is derived. Moreover, the stability bound of the singular perturbation parameter can be obtained by solving a set of matrix inequalities. Finally, two numerical examples are given to illustrate the effectiveness of the proposed results. © 2012 IEEE.","Title: Exponential stability of nonlinear time-delay systems with delayed impulse effects\nYear: 2011\n\nAbstract: The problem of exponential stability for nonlinear time-delay systems with delayed impulses is addressed in this paper. Lyapunov-based sufficient conditions for exponential stability are derived, respectively, for two kinds of delayed impulses (i.e., destabilizing delayed impulses and stabilizing delayed impulses). It is shown that if a nonlinear impulsive time-delay system without impulse input delays is exponentially stable, then under some conditions, its stability is robust with respect to small impulse input delays. Moreover, it is also shown that for a stable nonlinear impulsive time-delay system, if the magnitude of the delayed impulses is sufficiently small, then under some conditions, the delayed impulses do not destroy the stability irrespective of the sizes of the impulse input delays. The efficiency of the proposed results is illustrated by three numerical examples.","Title: On Sampled-Data Control for Master-Slave Synchronization of Chaotic Lur'e Systems.\nYear: 2012\n\nAbstract: This brief presents a new method for master-slave synchronization of chaotic Lur'e systems with sampled-data control. The new method is based on a novel construction of piecewise differentiable Lyapunov functionals in the framework of the input delay approach. The new Lyapunov functional is continuous at sampling times but not necessarily positive definite inside the sampling intervals. Compared w...","Title: Input-to-state stability and integral input-to-state stability of nonlinear impulsive systems with delays\nYear: 2009\n\nAbstract: This paper is concerned with analyzing input-to-state stability (ISS) and integral-ISS (iISS) for nonlinear impulsive systems with delays. Razumikhin-type theorems are established which guarantee ISS/iISS for delayed impulsive systems with external input affecting both the continuous dynamics and the discrete dynamics. It is shown that when the delayed continuous dynamics are ISS/iISS but the discrete dynamics governing the impulses are not, the ISS/iISS property of the impulsive system can be retained if the length of the impulsive interval is large enough. Conversely, when the delayed continuous dynamics are not ISS/iISS but the discrete dynamics governing the impulses are, the impulsive system can achieve ISS/iISS if the sum of the length of the impulsive interval and the time delay is small enough. In particular, when one of the delayed continuous dynamics and the discrete dynamics are ISS/iISS and the others are stable for the zero input, the impulsive system can keep ISS/iISS no matter how often the impulses occur. Our proposed results are evaluated using two illustrative examples to show their effectiveness.","Title: Delay-dependent output feedback guaranteed cost control for uncertain time-delay systems\nYear: 2004\n\nAbstract: This paper considers the problem of output-feedback guaranteed cost controller design for uncertain time-delay systems. By representing the time-delay system in the descriptor form and using a recent result on bounding of cross products of vectors, we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost output-feedback controller in terms of matrix inequalities. A numerical algorithm is proposed to construct a full order output feedback controller achieving a suboptimal guaranteed cost such that the system can be stabilized for all admissible uncertainties. An example is presented which shows that the proposed method can produce a lower guaranteed cost than the delay-independent method.","Title: Global exponential stability of impulsive neural networks with variable delay: an LMI approach\nYear: 2009\n\nAbstract: This paper focuses on the problem of global exponential stability analysis of impulsive neural networks with variable delay. Three types of impulses are considered: the impulses are input disturbances; the impulses are \"neutral\" type (that is, they are neither helpful for stability of neural networks nor destabilizing); and the impulses are stabilizing. For each type of impulses, by using Lyapunov function and Razumikhin-type techniques, the sufficient conditions for global exponential stability are developed in terms of linear matrix inequalities with respect to suitable classes of impulse time sequences. The new sufficient stability conditions do not impose any restriction on the size of time-delay. Numerical examples are given which show our results are less conservative than the existing sufficient stability conditions.","Title: Improved delay-dependent asymptotic stability criteria for delayed neural networks.\nYear: 2008\n\nAbstract: This brief is concerned with asymptotic stability of neural networks with uncertain delays. Two types of uncertain delays are considered: one is constant while the other is time varying. The discretized Lyapunov-Krasovskii functional (LKF) method is integrated with the technique of introducing the free-weighting matrix between the terms of the Leibniz-Newton formula. The integrated method leads to the establishment of new delay-dependent sufficient conditions in form of linear matrix inequalities for asymptotic stability of delayed neural networks (DNNs). A numerical simulation study is conducted to demonstrate the obtained theoretical results, which shows their less conservatism than the existing stability criteria.","Title: An Improved Stabilization Method for Sampled-Data Control Systems With Control Packet Loss.\nYear: 2012\n\nAbstract: This technical note presents a new method for stability analysis and stabilization of sampled-data systems with control packet loss. It is assumed that if the control packet from the controller to the actuator is lost, then the actuator input to the plant is set to zero. The new method is based on a novel construction of piecewise differentiable Lyapunov functionals by using an impulsive system representation of sampled-data systems. A significant feature of the new Lyapunov functionals is that they are continuous at impulse times but not necessarily positive definite inside the impulse intervals. Applying the new Lyapunov functionals to sampled-data systems with control packet loss, improved criteria for stability and stabilization are derived. The new criteria are proved theoretically to be less conservative than the existing results. Illustrative examples are given which substantiate the usefulness of the proposed method. © 2011 IEEE.","Title: Stability analysis for switched systems with time-varying delay and parametric uncertainties\nYear: 2010\n\nAbstract: This paper addresses the stability problem for switched systems with time-varying delay and parametric uncertainties. The main idea is to construct new piecewise time-varying Lyapunov functionals/functions such that they are decreasing at switching time instants in spite of their discontinuity at those switching time instants. Then the constructed piecewise time-varying Lyapunov functionals/functions are used to derive sufficient conditions for the existence of delay-independent minimum dwell time, which guarantee the exponential stability of switched delay systems for any bounded delays. The theoretical findings are validated by an illustrative example.","Title: On improved robust stabilization of uncertain systems with unknown input delay\nYear: 2006\n\nAbstract: This paper investigates the robust stabilization problem for uncertain systems with unknown input delay based on the reduction method. Two types of the unknown input delay are considered: one is constant; the other is continuous and may vary fast. Sufficient matrix inequalities conditions for stabilizability of such systems are derived via Lyapunov functionals and the descriptor system approach to time-delay systems. An algorithm involving convex optimization is proposed to design a delayed state feedback controller such that the system can be stabilized for all admissible uncertainties. Two illustrative examples are presented to show the effectiveness of the proposed algorithm.","Title: Stability analysis for time-delay systems with partial states subject to impulsive inputs\nYear: 2009\n\nAbstract: In practice, there exist such controlled systems in which some states are often not available, not measurable or too expensive to measure. For such systems, impulsive control inputs may be exerted on the available partial states so as to stabilize the underlying systems. This paper is concerned with analyzing the stability of a class of nonlinear time-delay systems with partial states subject to impulsive inputs. The main idea is that the entire impulsively controlled system can be viewed as a hybrid one that is composed of a stable continuous subsystem and a stable impulsive subsystem. Then the analysis technique based on the new time-varying weighted Lyapunov functional/function introduced is utilized to derive sufficient conditions for exponential stability of such systems. As an illustration of the utility of the new stability criteria, the batch reactor system with the try-once-discard protocol is examined.","Title: Delayed Impulsive Control of Takagi–Sugeno Fuzzy Delay Systems\nYear: 2013\n\nAbstract: In this paper, the problem of exponential stability for Takagi–Sugeno (T–S) fuzzy delay systems with delayed impulses is addressed. By means of the time-dependent Lyapunov function method combined with Razumikhin technique, a sufficient condition expressed in terms of linear matrix inequalities (LMIs) is obtained for exponential stability of T–S fuzzy delay systems with delayed impulses. The derived stability condition depends both on the lower bound and the upper bound of impulsive intervals, which is robust with respect to small impulse input delays. By solving a set of LMIs, an impulsive state feedback controller can be easily constructed. Two numerical examples are discussed to illustrate the effectiveness of the theoretical findings.","Title: Asymptotic Stability in a Neutral Delay Differential System with Variable Delays\nYear: 2006\n\nAbstract: By applying M-matrix theory and some new analysis techniques, we have succeeded in establishing the asymptotic stability of the zero solution of the \"pure-delay type\" neutral system with variable delays. The criteria obtained in this paper extend and improve the existing ones.","Title: Delay-dependent guaranteed cost control for uncertain discrete-time systems with both state and input delays\nYear: 2004\n\nAbstract: This paper considers the guaranteed cost control problem for a class of uncertain linear discrete-time systems with both state and input delays. By representing the time-delay system in the descriptor system form and using a recent result on bounding of cross products of vectors, we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost controller in terms of linear matrix inequalities. Numerical examples are presented which shows that the proposed method can even produce a lower guaranteed cost than the delay-independent methods.","Title: A study of exponential stability for stochastic delayed neural networks\nYear: 2010\n\nAbstract: This paper is concerned with analyzing mean square exponential stability of stochastic delayed neural networks subject to parametric uncertainties. The discretized Lyapunov functional technique is first utilized to construct a new Lyapunov functional in order to effectively deal with the time-varying delay. Then the free-weighting matrix technique and the convex combination method are used to establish a new delay-dependent mean square exponential stability criterion for uncertain stochastic delayed neural networks. The usefulness of the new theoretical findings is further demonstrated by numerical results.","Title: Impulsive observers with variable update intervals for Lipschitz nonlinear time-delay systems\nYear: 2013\n\nAbstract: This article is concerned with the design of impulsive observers with variable update intervals for Lipschitz nonlinear systems with delays in state. Discontinuous Lyapunov function/funtional approaches are developed to analyse the stability of error dynamics. Delay-independent sufficient conditions for uniform exponential stability of the error dynamics over variable update intervals are derived in terms of linear matrix inequalities LMIs. When these LMIs are feasible, the observer gain matrix can be solved numerically with an LMI-based optimisation algorithm. Numerical examples are provided to show the efficiency of the proposed approach.","Title: Delay-dependent stability and H∞ control of uncertain discrete-time Markovian jump systems with mode-dependent time delays\nYear: 2004\n\nAbstract: This paper considers the problems of stability, stabilization and H∞ control via memoryless state feedback for uncertain discrete-time Markovian jump linear systems with mode-dependent time delays. Based on linear matrix inequalities, delay-dependent solutions are obtained by using a descriptor model transformation of the system and by applying a new bounding technique for cross terms. Numerical examples are presented to illustrate the usefulness of the theoretical results.","Title: Delay-dependent robust stabilization for uncertain neutral systems with distributed delays\nYear: 2007\n\nAbstract: The problems of robust stability and robust stabilization of uncertain neutral systems with distributed delays are studied in this paper. Using a combination of integral inequality technique and descriptor system approach, new delay-dependent sufficient conditions for robust stability and robust stabilization are formulated in terms of linear matrix inequalities (LMIs). LMI-based conditions are also derived for robust stability and robust stabilizability of uncertain distributed-delay systems when the distributed delay belongs to a given interval. When the results obtained in this paper are applied to stabilization of combustion in the chamber of a liquid monopropellant rocket motor, it is found that the combustion can be robustly stabilized over larger variation intervals of pressure parameter and time-delay parameter than those obtained in Zheng and Frank [(2002). Robust control of uncertain distributed delay systems with application to the stabilization of combustion in rocket motor chambers. Automatica, 38, 487–497].","Title: On Global Asymptotic Stability of Cohen–Grossberg Neural Networks With Variable Delays\nYear: 2008\n\nAbstract: This paper studies the problems of existence, uniqueness, global asymptotic stability and global exponential stability of the equilibrium of Cohen-Grossberg neural networks with variable delays. An estimation technique based on delay differential inequality with variable coefficients is developed to establish delay-independent/delay-dependent sufficient conditions for global asymptotic/exponential stability. The stability criteria obtained are based on the M-matrix theory. These criteria can be easily checked in practice and do not require that the delays be constant or differentiable. In particular, our delay-independent asymptotic/exponential stability criteria remove a restriction on the amplification functions imposed by the existing results. Furthermore, our delay-dependent exponential stability criteria give explicitly the allowable upper bound on the diagonal delays such that the global stability property of Cohen-Grossberg neural networks can be retained. Thus, our new results are of great importance in design and application of Cohen-Grossberg neural networks with variable delays. The effectiveness of the new results is further illustrated by two numerical examples in comparison with the existing results.","Title: Delay-Dependent Exponential Stability of Neural Networks With Variable Delay: An LMI Approach\nYear: 2006\n\nAbstract: This brief focuses on the problem of delay-dependent stability analysis of neural networks with variable delay. Two types of variable delay are considered: one is differentiable and has bounded derivative; the other one is continuous and may vary very fast. By introducing a new type of Lyapunov-Krasovskii functional, new delay-dependent sufficient conditions for exponential stability of delayed neural networks are derived in terms of linear matrix inequalities. We also obtain delay-independent stability criteria. Two examples are presented which show our results are less conservative than the existing stability criteria.","Title: Stability analysis of delayed cellular neural networks with impulsive effects.\nYear: 2011\n\nAbstract: This paper focuses on the problem of exponential stability analysis of delayed cellular neural networks (DCNNs) with impulsive effects. The time delay is allowed to be time varying. By utilizing the piecewise linear property of the activation function of DCNNs and applying Razumikhin-type analysis techniques, two different types of delay-independent criteria for exponential stability of DCNNs with...","Title: Global asymptotic stability of a class of neural networks with distributed delays\nYear: 2006\n\nAbstract: In this paper, the problem of stability analysis for a class of neural networks with distributed delays is investigated. Applying the M-matrix theory and new analysis technique, novel sufficient conditions for the existence, uniqueness, and global asymptotic stability of the equilibrium point of neural networks with distributed delays are derived. The new stability criteria can be applied to the case when the nondelayed terms cannot dominate the delayed terms, which have great significance in the design and application of neural networks with distributed delays. Three illustrative examples are presented which demonstrate the usefulness of the proposed results","Title: Guaranteed cost control for uncertain markovian jump systems with mode-dependent time-delays\nYear: 2003\n\nAbstract: This note concerns the robust guaranteed cost control problem for a class of continuous-time Markovian jump linear system with norm-bounded uncertainties and mode-dependent time-delays. The problem is to design a memoryless state feedback control law such that the closed-loop system is stochastically stable and the closed-loop cost function value is not more than a specified upper bound for all admissible uncertainties. Based on linear matrix inequality, delay-dependent sufficient conditions for the existence of such controller are derived by using a descriptor model transformation of the system and by applying Moon's inequality for bounding cross terms. Sufficient conditions which depend on the difference between the largest and the smallest time-delays are also presented. Two numerical examples are given for illustration of the proposed theoretical results.","Title: Input-to-state stability for networked control systems via an improved impulsive system approach\nYear: 2011\n\nAbstract: This paper presents a novel impulsive system approach to input-to-state stability (ISS) analysis of networked control systems (NCSs) with time-varying sampling intervals and delays. This approach is based upon the new idea that an NCS can be viewed as an interconnected hybrid system composed of an impulsive subsystem and an input delay subsystem. A new type of time-varying discontinuous Lyapunov-Krasovskii functional, which makes full use of the information on the piecewise-constant input and the bounds of the network delays, is introduced to analyze the ISS property of NCSs. Linear matrix inequality based sufficient conditions are derived for ISS of NCSs with respect to external disturbances. When applied to the approximate tracking problem for NCSs, the derived ISS result provides bounds on the steady-state tracking error. Numerical examples are provided to show the efficiency of the proposed approach.","Title: A new method for complete stability analysis of cellular neural networks with time delay.\nYear: 2010\n\nAbstract: This paper presents new complete stability results for delayed cellular neural networks (DCNNs). A novel method is proposed for complete stability analysis of DCNNs. By applying the M-matrix theory and introducing some new estimation techniques on the solutions of DCNNs, a simple and improved complete stability criterion is derived. The new criterion unifies the delay-dependent and delay-independent complete stability conditions for DCNNs. Moreover, the obtained delay-dependent criterion can give a larger upper bound of the time delay than the existing ones such that the complete stability can still be retained. Numerical examples are presented which show that the new complete stability results for DCNNs are compared favorably with the existing results.","Title: Delay-dependent stability and stabilizability of uncertain jump bilinear stochastic systems with mode-dependent time-delays\nYear: 2005\n\nAbstract: This paper considers the problems of robust stability and robust stabilizability for a class of uncertain jump bilinear stochastic systems with mode-dependent time delays. By transforming the jump system under consideration into an equivalent descriptor jump system, a new stochastic Lyapunov functional is introduced for stability analysis and control design. Novel delay-dependent sufficient conditions in terms of linear matrix inequalities are derived for robust stability and robust stabilizability. Two numerical examples are given for the illustration of the proposed theoretical results.","Title: Robust stability analysis for stochastic neural networks with time-varying delay.\nYear: 2010\n\nAbstract: This brief investigates the problem of mean square exponential stability of uncertain stochastic delayed neural networks (DNNs) with time-varying delay. A novel Lyapunov functional is introduced with the idea of the discretized Lyapunov-Krasovskii functional (LKF) method. Then, a new delay-dependent mean square exponential stability criterion is derived by applying the free-weighting matrix technique and by equivalently eliminating time-varying delay through the idea of convex combination. Numerical examples illustrate the effectiveness of the proposed method and the improvement over some existing methods.","Title: Delay-Independent Minimum Dwell Time for Exponential Stability of Uncertain Switched Delay Systems.\nYear: 2010\n\nAbstract: In this technical note, the problem of delay-independent minimum dwell time for exponential stability of uncertain switched delay systems is considered. Piecewise time-varying Lyapunov functionals/functions which are decreasing at switching times by construction are introduced to investigate exponential stability of switched delay systems with constant or time-varying delays. This type of delicately constructed Lyapunov functionals/functions can efficiently eliminate the jump phenomena of adjacent Lyapunov functionals/functions at switching times without imposing any restriction on the sizes of time-delays. By applying this type of Lyapunov functionals/functions, it is shown that if each subsystem is delay-independently exponentially stable, then under some conditions there exists a delay-independent minimum dwell time in the sense that the switched delay system with such minimum dwell time is exponentially stable irrespective of the sizes of the time-delays. Two numerical examples are provided to demonstrate the efficiency of the proposed approach.","Title: Stability Analysis and H∞-Control of Delayed Neutral Stochastic Systems with Time-Varying Parameter Uncertainties\nYear: 2006\n\nAbstract: This paper is concerned with studying robust stochastic stability, stabilization and H∞-control of uncertain neutral stochastic systems with time-delay. Under the assumption that parametric uncertainties are time-varying and norm-bounded, delay-dependent sufficient conditions expressed by linear matrix inequalities are derived for the problems of robust stochastic stability, stabilization and H∞-control of uncertain neutral stochastic systems with time-delay. The usefulness of the theoretical results is exemplified by two numerical examples","Title: Impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks.\nYear: 2015\n\nAbstract: This paper investigates the problems of impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks (DDNNs). Two types of DDNNs with stabilizing impulses are studied. By introducing the time-varying Lyapunov functional to capture the dynamical characteristics of discrete-time impulsive delayed neural networks (DIDNNs) and by using a convex combination technique, new exponential stability criteria are derived in terms of linear matrix inequalities. The stability criteria for DIDNNs are independent of the size of time delay but rely on the lengths of impulsive intervals. With the newly obtained stability results, sufficient conditions on the existence of linear-state feedback impulsive controllers are derived. Moreover, a novel impulsive synchronization scheme for two identical DDNNs is proposed. The novel impulsive synchronization scheme allows synchronizing two identical DDNNs with unknown delays. Simulation results are given to validate the effectiveness of the proposed criteria of impulsive stabilization and impulsive synchronization of DDNNs. Finally, an application of the obtained impulsive synchronization result for two identical chaotic DDNNs to a secure communication scheme is presented.","Title: Global exponential stability of a class of impulsive neural networks with unstable continuous and discrete dynamics.\nYear: 2015\n\nAbstract: This paper deals with global exponential stability of a class of impulsive neural networks whose continuous and discrete dynamics are unstable. Assuming that the impulsive neural network under consideration can be decomposed into two lower order impulsive systems, a time-varying weighted Lyapunov function associated with the impulse time sequence is introduced for stability analysis. A novel global exponential stability criterion is derived in terms of linear matrix inequalities (LMIs). By employing the newly obtained stability criterion, a sufficient condition on the existence of a reduced-order impulsive controller is derived. Unlike the previous results concerning impulsive control, the proposed reduced-order impulsive controller only exerts the impulses on a partial set of the state vector. Moreover, the controller gain matrices can be achieved by solving a set of LMIs. Finally, four illustrative examples are given to show the effectiveness of the developed techniques and results.","Title: Global exponential stabilization of neural networks with time delay via impulsive control\nYear: 2014\n\nAbstract: The problem of global exponential stabilization of discrete-time delayed neural networks (DDNNs) via impulsive control is addressed in this paper. A novel time-varying Lyapunov functional is proposed to capture the dynamical characteristic of discrete-time impulsive delayed neural networks (DIDNNs). In conjunction with the convex combination technique, new conditions in the form of linear matrix inequalities are established for global exponential stability of DIDNNs. The distinct features of the new stability conditions for DIDNNs are that they are dependent upon the lengths of impulsive intervals but independent of the size of time delay. This paves the way for designing the impulsive controller for impulsive stabilization of DDNNs. The applicability of the developed global exponential stabilization conditions is validated by numerical results.","Title: Impulsive Synchronization of Reaction-Diffusion Neural Networks With Mixed Delays and Its Application to Image Encryption.\nYear: 2016\n\nAbstract: This paper presents a new impulsive synchronization criterion of two identical reaction-diffusion neural networks with discrete and unbounded distributed delays. The new criterion is established by applying an impulse-time-dependent Lyapunov functional combined with the use of a new type of integral inequality for treating the reaction-diffusion terms. The impulse-time-dependent feature of the pro...","Title: Robust sampled-data H∞ control of uncertain singularly perturbed systems using time-dependent Lyapunov functionals\nYear: 2015\n\nAbstract: In this paper, the problem of robust sampled-data H∞ control of linear uncertain singularly perturbed systems is investigated. The parametric uncertainties are assumed to be time-varying and norm-bounded. Two types of controller design are considered: 1 with a fast sampling in the fast state and a slow one in the slow state, and 2 with a fast sampling in both states. For each type, a time-dependent Lyapunov functional associated with the sampling pattern is introduced to analyse the exponential stability and L2-gain performance of the closed-loop system. Linear matrix inequalities based solutions of the robust sampled-data H∞ control problem are derived. The new results are proved theoretically to be less conservative than the existing results. An illustrative example is given which substantiates the usefulness of the proposed method.","Title: Periodically Intermittent Stabilization of Delayed Neural Networks Based on Piecewise Lyapunov Functions/Functionals\nYear: 2014\n\nAbstract: This paper is concerned with the stabilization problem of delayed neural networks via a periodically intermittent controller. Two cases of time-varying bounded delays are considered: one is the time-varying delay without any constraints on the delay derivative, while the other is the time-varying delay with the delay derivative less than 1. For the first case, a piecewise time-invariant Lyapunov function-based method is applied, and the derived stability criterion improves an existing result. For the second case, a piecewise time-varying Lyapunov functional is introduced to establish a new stability criterion. Then, the obtained stability criteria are employed to design periodically intermittent controllers. Finally, two numerical examples are provided to illustrate the merits of the proposed approach.","Title: Multistability in a class of stochastic delayed Hopfield neural networks.\nYear: 2015\n\nAbstract: In this paper, multistability analysis for a class of stochastic delayed Hopfield neural networks is investigated. By considering the geometrical configuration of activation functions, the state space is divided into 2(n)+1 regions in which 2(n) regions are unbounded rectangles. By applying Schauder's fixed-point theorem and some novel stochastic analysis techniques, it is shown that under some conditions, the 2(n) rectangular regions are positively invariant with probability one, and each of them possesses a unique equilibrium. Then by applying Lyapunov function and functional approach, two multistability criteria are established for ensuring these equilibria to be locally exponentially stable in mean square. The first multistability criterion is suitable to the case where the information on delay derivative is unknown, while the second criterion requires that the delay derivative be strictly less than one. For the constant delay case, the second multistability criterion is less conservative than the first one. Finally, an illustrative example is presented to show the effectiveness of the derived results.","Title: Globally exponential stabilization of neural networks with mixed time delays via impulsive control\nYear: 2015\n\nAbstract: The impulsive stabilization problem of neural networks with discrete time-varying delays and unbounded continuously distributed delays is considered. By using impulse-time-dependent Lyapunov function-based techniques to capture the hybrid structure characteristics of the considered impulsive neural networks, two novel global exponential stability criteria are obtained in terms of linear matrix inequalities, which are capable of dealing with the case where both the continuous and discrete dynamics are unstable. When the original continuous-time delayed neural networks are not stable, sufficient conditions are developed for the design of exponentially stable linear impulsive state feedback controllers. Four numerical examples are given to illustrate the less conservatism and effectiveness of the proposed results.","Title: Adaptive impulsive observers for nonlinear systems: Revisited\nYear: 2015\n\nAbstract: This paper revisits the design of adaptive impulsive observers (AIOs) for nonlinear systems. The dynamics of observer state of the proposed AIO is modelled by an impulsive differential equation, by which the observer state is updated in an impulsive fashion. The parameter estimation law is modelled by an impulse-free time-varying differential equation associated with the impulse time sequence for determining when the observer state is updated. Unlike the previous work, the convergence analysis of the estimation error system is performed by applying a time-varying Lyapunov function based method, in conjunction with the application of a generalized version of Barbalat’s Lemma. A sufficient condition for the existence of AIOs is also derived. For some special cases, it is shown that the sufficient condition can be formulated in terms of linear matrix inequalities (LMIs), and the observer matrices can be attained by solving a set of LMIs. Furthermore, with an additional persistence-of-excitation-type constraint, it is proved that the sufficient condition can guarantee the convergence of parameter estimation. Two examples of chaotic oscillators are provided to illustrate the design procedure of the proposed AIOs.","Title: Delay-independent stabilization of a class of time-delay systems via periodically intermittent control.\nYear: 2016\n\nAbstract: The problem of delay-independently periodically intermittent stabilization for a class of time-delay systems is examined. First, the stability of the considered periodically intermittently controlled time-delay systems is analyzed by using the piecewise switching-time-dependent Lyapunov function/functional. The introduced Lyapunov function/functional is nonincreasing at switching instants, which can guarantee the exponential stability of the considered systems irrespective of the sizes of the state delays. Next, based on the newly established stability criteria, sufficient conditions for the existence of delay-independently periodically intermittent state-feedback controllers are derived. Finally, two illustrative examples are presented to show the validity of the obtained results.","Title: Aperiodically intermittent H∞ synchronization for a class of reaction-diffusion neural networks.\nYear: 2017\n\nAbstract: In this paper, the intermittent H ∞ synchronization problem for a class of reaction-diffusion neural networks with Dirichlet boundary conditions is investigated. Different from the previous works concerning intermittent synchronization, it is assumed that the response system is subject to external disturbance, and both the control period and the control width may be variable. A switching-time-dependent Lyapunov function combined with the use of the extended Wiritinger's inequality for exploring the stabilizing role of the reaction-diffusion term is employed to analyze the exponential stability and L2-gain performance of the synchronization error dynamics. In the framework of linear matrix inequalities, the aperiodically intermittent H ∞ synchronization controller is designed, which guarantees internally exponential stability as well as a prescribed L2-gain from the exogenous input to the regulated error output. Two numerical examples are given to illustrate the effectiveness of the proposed method.","Title: Bipartite Consensus For Multiple Two-Time Scales Agents Over The Signed Digraph\nYear: 2016\n\nAbstract: The bipartite consensus problem of multiple twotime scales agents over the signed digraph, where both cooperative and competitive interactions exist among the agents, is considered with a new distributed protocol. Sufficient conditions for bipartite consensus is presented in terms of easily checkable algebraic Riccati equation (ARE). Compared with the existing result on consensus of multiple two-time scales agents, the communication topology here is more generic. Moreover, the upper bound of the singular perturbation parameter is also presented. Simulation examples are given to illustrate the effectiveness of the proposed results.","Title: Generating Globally Stable Periodic Solutions of Delayed Neural Networks With Periodic Coefficients via Impulsive Control.\nYear: 2017\n\nAbstract: This paper is dedicated to designing periodic impulsive control strategy for generating globally stable periodic solutions for periodic neural networks with discrete and unbounded distributed delays when such neural networks do not have stable periodic solutions. Two criteria for the existence of globally exponentially stable periodic solutions are developed. The first one can deal with the case w...","Title: Impulsive stabilization of a class of singular systems with time-delays.\nYear: 2017\n\nAbstract: This paper deals with the impulsive stabilization problem for a class of linear singular systems with time-delays. The stabilization is achieved by only exerting impulsive action on the slow state variables. Two novel Lyapunov methods are presented to determine exponential stability of the impulsively controlled systems. For the case where the time-delay is unknown and may be time-varying, a Lyapunov–Razumikhin method is developed, in which the Razumikhin condition is constructed by exploiting the relation among the fast state variables, the slow state variables, and their initial values. For the case where the delay derivative is strictly less than 1, a descriptor type of impulse-time-dependent Lyapunov functional is introduced, which is discontinuous at impulse times but does not grow along the state trajectories by construction. By using a convex technique, the stability criteria are expressed in terms of linear matrix inequalities (LMIs). Then, the impulsive controllers can be designed in the framework of LMIs. The effectiveness and advantages of the proposed methods are confirmed through simulation results.","Title: Impulsive H∞ synchronization for reaction-diffusion neural networks with mixed delays.\nYear: 2018\n\nAbstract: This paper presents a study on impulsive H∞ synchronization analysis of reaction–diffusion neural networks with discrete and distributed delays. It is assumed that the output information of the drive system is only available at discrete instants, and the dynamics of the response system are subject to external disturbance. To achieve H∞ synchronization, an impulsive synchronization strategy is proposed which is based on feedback from the sampled-data of the drive and response dynamics. Novel time-dependent Lyapunov function/functional methods are developed for L2-gain analysis of synchronization error systems, both for fast-varying delays and for slowly-varying delays. LMI-based optimization methods are suggested to design impulsive H∞ synchronization controllers with minimized feedback gain. Numerical simulations are provided to validate the effectiveness of the theoretical results.","Title: Stability and L2-gain analysis for impulsive delay systems: An impulse-time-dependent discretized Lyapunov functional method.\nYear: 2017\n\nAbstract: The problems of exponential stability and L2-gain for a class of time-delay systems with impulsive effects are studied. The main tool used is the construction of an impulse-time-dependent complete Lyapunov functional. By dividing the impulse interval and delay interval into several segments, the matrix functions of this functional are chosen to be continuous piecewise linear. Moreover, an impulse-time-dependent weighting factor is introduced to coordinate the dynamical behavior of the nondelayed and integral terms of this functional along the trajectories of the system. By applying this functional, delay-dependent sufficient conditions for exponential stability and L2-gain are derived in terms of linear matrix inequalities. As by-products, new delay-independent sufficient conditions for the same problems are also derived. The efficiency of the proposed results is illustrated by numerical examples.","Title: Modulus Consensus In A Network Of Singularly Perturbed Systems With Collaborative And Antagonistic Interactions\nYear: 2017\n\nAbstract: This paper addresses the modulus consensus in a network of singularly perturbed systems, all of which own multi-time scales characteristics. The interactions among the agents are collaborative and antagonistic interactions, and it can been modelled by a signed directed graph. Also, the effect of time-varying delay has been taken into account when modelling the agent dynamics. Based on singularly perturbed decomposition method, Kronecker product technique and the comparison principle, several sufficient conditions are presented under which networked singularly perturbed time-varying delay systems with collaborative and antagonistic interactions achieve modulus consensus. Moreover, the upper bound of singular perturbation parameter is deduced explicitly. Two simulation examples are presented to illustrate the validity of the proposed results.","Title: On Stabilization Of Delayed Linear Singular Systems Via Impulsive Control\nYear: 2017\n\nAbstract: This paper is concerned with the stability problem of a class of delayed linear singular systems based on impulsive control. The key idea is to develop two novel Lyapunov methods to effectively deal with two different cases of delays: fast time-varying delay and slow time-vary delay. These Lyapunov methods take good advantage of the hybrid structure characteristics of the impulsively controlled singular systems so as to establish exponential stability of the underlying singular systems. A convex technique is applied to represent the derived stability conditions within the linear matrix inequalities framework, which facilitates design of the desired impulsive controllers. An illustrative example is given to substantiate the efficiency of the developed exponential impulsive stabilization conditions.","Title: Sampled-data distributed H∞ control of a class of 1-D parabolic systems under spatially point measurements.\nYear: 2017\n\nAbstract: This paper considers the sampled-data distributed H∞ control problem for 1-D semilinear transport reaction equations with external disturbances. It is assumed that a finite number of point spatial state measurements are available. A Razumikhin-type approach is developed for stability and L2-gain analysis of the closed-loop system. In contrast to Halanay׳s inequality based approach, the proposed Razumikhin-type approach not only provides a subtle decay estimate of the selected Lyapunov functional, but also guarantees the H∞ performance index to be negative if certain conditions are satisfied. By introducing a time-dependent Lyapunov functional combined with the use of Wirtinger׳s inequality, sufficient conditions for the internal exponential stability and finite L2-gain are derived in terms of linear matrix inequalities. The obtained conditions establish a quantitative relation among the upper bounds on the spatial sampling intervals and the time sampling intervals, and L2-gain. Two numerical examples are provided to illustrate the usefulness of the proposed theoretical results.","Title: Multiple switching-time-dependent discretized Lyapunov functions/functionals methods for stability analysis of switched time-delay stochastic systems.\nYear: 2018\n\nAbstract: This paper presents novel approaches for stability analysis of switched linear time-delay stochastic systems under dwell time constraint. Instead of using comparison principle, piecewise switching-time-dependent discretized Lyapunov functions/functionals are introduced to analyze the stability of switched stochastic systems with constant or time-varying delays. These Lyapunov functions/functionals are decreasing during the dwell time and non-increasing at switching instants, which lead to two mode-dependent dwell-time-based delay-independent stability criteria for the switched systems without restricting the stability of the subsystems. Comparison and numerical examples are provided to show the efficiency of the proposed results.","Title: Disturbance-observer-based control design for a class of uncertain systems with intermittent measurement.\nYear: 2017\n\nAbstract: The robust control problem of a class of uncertain systems subject to intermittent measurement as well as external disturbances is considered. The disturbances are supposed to be generated by an exogenous system, while the state information is assumed to be available only on some nonoverlapping time intervals. A composite design consisting of an intermittent state feedback controller augmented by a disturbance compensation term derived from a disturbance observer is formulated. Unlike the conventional disturbance observers, the proposed disturbance observer is modelled by a switched impulsive system, which makes use of the intermittent state data to estimate the disturbances. Stability analysis of the resulting closed-loop system is performed by applying a piecewise time-dependent Lyapunov function. Then a sufficient condition for the existence of the proposed composite controllers is derived in terms of linear matrix inequalities (LMIs). The controller and observer gains can be achieved by solving a set of LMIs. Further, a procedure to limit the norms of the controller and observer gains is given. Finally, an illustrative example is presented to demonstrate the validity of the results.","Title: Impulsive effects on the stability and stabilization of positive systems with delays.\nYear: 2017\n\nAbstract: •Exponential stability and positive stabilization for impulsive positive systems(IPSs) with delay are studied.•Three types of impulses are taken into consideration.•The Lyapunov–Razumikhin techniques are utilized for stability analysis.","Title: A new method for global stability analysis of delayed reaction-diffusion neural networks.\nYear: 2018\n\nAbstract: This paper presents improved criteria for global exponential stability of reaction–diffusion neural networks with time-varying delays. A novel diffusion-dependent Lyapunov functional, which is directly linked to the diffusion terms, is suggested to analyze the role of diffusivity of each neuron on the model dynamics. In the case of Dirichlet boundary conditions, the extended Wirtinger’s inequality is employed to exploit the stabilizing effect of reaction–diffusion terms. In the framework of descriptor system approach, the augmented Lyapunov functional technique is utilized to reduce the conservatism in the values of the time delay bounds. As a result, the derived global stability criteria are more effective than the existing ones. Three numerical examples are provided to illustrate the effectiveness of the proposed methodology.","Title: Synchronization Analysis of Two-Time-Scale Nonlinear Complex Networks With Time-Scale-Dependent Coupling.\nYear: 2019\n\nAbstract: In this paper, a time-scale-dependent coupling scheme for two-time-scale nonlinear complex networks is proposed. According to this scheme, the inner coupling matrices are related to the fast dynamics of individual subsystems, but are no longer time-scale-independent. Designing time-scale-dependent inner coupling matrices is motivated by the fact that the difference of time scales is an essential feature of modular architecture of two-time-scale systems. Under the novel coupling framework, the previous assumption on individual two-time-scale subsystems that the fast dynamics must be exponentially stable can be removed. The idea of time-scale separation is employed to analyze the stability of synchronization error systems via weighted ϵ-dependent Lyapunov functions. For a given upper bound of the singular perturbation parameter ϵ, it is proved that the exponential decay rate of the synchronization error can be guaranteed to be independent of the value of ϵ. In this way, criteria for local and global exponential synchronization are established. The allowable upper bound of ϵ such that the synchronizability of the considered two-time-scale network is retained can be obtained by solving a set of ϵ-dependent matrix inequalities. Finally, the efficiency of the proposed time-scale-dependent coupling strategy is demonstrated through numerical simulations.","Title: Dissipativity of Singularly Perturbed Lur’e Systems\nYear: 2019\n\nAbstract: The dissipativity problem of singularly perturbed Lur'e systems is investigated in this brief. Two new storage functions are constructed to explore the dynamics of both the fast and slow models, as well as their interaction more efficiently. By using the merit of the proposed storage functions, some new ε-uniformly strict dissipativity criteria in terms of well-conditioned linear matrix inequaliti...","Title: Dynamic event-triggered control for linear stochastic systems with sporadic measurements and communication delays\nYear: 2019\n\nAbstract: This paper deals with the stability of linear stochastic systems in the presence of sporadic measurements and communication delays. Motivated by considerations about the efficient use of the available resources, two so-called dynamic discrete-time event-triggered control (DTETC) strategies tailored to the system are designed, including some existing periodic event-triggered control strategies as particular cases. An impulsive switched system approach and a switched time-delay system approach are developed for modeling and stability analysis of the resulting closed-loop systems, respectively. In addition, it is shown that under the same decay rate, the designed dynamic DTETC may further reduce the conservatism than their static counterparts. Interestingly, the proposed impulsive switched system approach can capture the stabilizing effect of the communication delays. A numerical example is provided to illustrate the theoretical results.","Title: New stability criteria for linear impulsive systems with interval impulse-delay\nYear: 2021\n\nAbstract: The robust stability problem for linear time-delay systems with general linear delayed impulses is investigated. Different from the previous results, the impulse-delays are allowed to be larger than the impulse period. An auxiliary state variable is introduced to construct an augmented model of the impulsive system, under which the discrete dynamics introduced by impulse-delays can be highlighted. A novel piecewise Lyapunov functional is introduced to analyze the stability of the augmented model. This functional is continuous along the trajectories of the augmented model, and is not required to be positive-definite at non-impulse instants. LMI-based exponential stability conditions are derived, which depend on both the impulse-dwell-time and the impulse-delay-interval. Numerical examples show that the obtained stability criteria are able to handle the benefit/harmful impulse-delays.","Title: A refined discretized timer-dependent Lyapunov functional for impulsive delay systems\nYear: 2021\n\nAbstract: A new type of discretized Lyapunov functional is introduced for stability and hybrid L2×l2-gain analysis of linear impulsive delay systems. This functional consists of three parts. The first part is the conventional discretized functional for delay-independent stability analysis. The second part is the looped-functionals-like functional for exploiting the internal structure inside impulse intervals, in which the decision matrix functions are approximated by piecewise linear matrix functions. The third part is a discretized adjustive factor, which makes the proposed Lyapunov functional continuous along the system trajectories. Thanks to this continuity, the resultant criteria for exponential stability and finite hybrid L2×l2-gain are expressed in terms of a combination of the continuous and discrete parts of the system. It is shown through numerical examples that the accuracy of the stability test increases with the increase of the partition number on impulse intervals, and the convergence rate is faster than that of the previous discretized functionals-based approach.","Title: Impulsive average-consensus of multi-agent systems with time-delays\nYear: 2022\n\nAbstract: In this paper, the impulsive average-consensus problem of first-order multi-agent systems with dynamically changing topologies is investigated. Continuous-time dynamics and impulsive protocols are both subjected to effects from nonuniform time-varying communication delays. By utilizing Razumikhin techniques and time-varying Lyapunov function method, some impulse-delay-dependent sufficient criteria for the average-consensus of multi-agent systems are derived. In addition, the discrete-time connection digraph is designed in terms of linear matrix inequalities for given impulsive sequences and some programming skills are used to make the discrete-time topology meet the needs of the actual environment. Numerical simulations are given to illustrate the effectiveness and validity of the theoretical results."],"string":"[\n \"Title: Delay-dependent exponential stability of uncertain stochastic systems with multiple delays: an LMI approach\\nYear: 2005\\n\\nAbstract: In this paper, the problem of exponential stability in mean square for stochastic systems with multiple delays is investigated. A delay-dependent sufficient condition is derived in terms of linear matrix inequalities (LMIs) by using a descriptor model transformation of the system and by applying Moon's inequality for bounding cross terms. The criteria obtained in this paper can be tested numerically very efficiently using interior point algorithms. An example shows that the proposed methods are less conservative than the other methods.\",\n \"Title: Robust Stability of Singularly Perturbed Impulsive Systems Under Nonlinear Perturbation.\\nYear: 2013\\n\\nAbstract: The robust stability problem for singularly perturbed impulsive systems under nonlinear perturbation is considered. The uncertainties are assumed to be limited by their upper norm bound. By applying the vector Lyapunov function method and a two-time scale comparison principle, a sufficient condition that ensures robust exponential stability for sufficiently small singular perturbation parameter is derived. Moreover, the stability bound of the singular perturbation parameter can be obtained by solving a set of matrix inequalities. Finally, two numerical examples are given to illustrate the effectiveness of the proposed results. © 2012 IEEE.\",\n \"Title: Exponential stability of nonlinear time-delay systems with delayed impulse effects\\nYear: 2011\\n\\nAbstract: The problem of exponential stability for nonlinear time-delay systems with delayed impulses is addressed in this paper. Lyapunov-based sufficient conditions for exponential stability are derived, respectively, for two kinds of delayed impulses (i.e., destabilizing delayed impulses and stabilizing delayed impulses). It is shown that if a nonlinear impulsive time-delay system without impulse input delays is exponentially stable, then under some conditions, its stability is robust with respect to small impulse input delays. Moreover, it is also shown that for a stable nonlinear impulsive time-delay system, if the magnitude of the delayed impulses is sufficiently small, then under some conditions, the delayed impulses do not destroy the stability irrespective of the sizes of the impulse input delays. The efficiency of the proposed results is illustrated by three numerical examples.\",\n \"Title: On Sampled-Data Control for Master-Slave Synchronization of Chaotic Lur'e Systems.\\nYear: 2012\\n\\nAbstract: This brief presents a new method for master-slave synchronization of chaotic Lur'e systems with sampled-data control. The new method is based on a novel construction of piecewise differentiable Lyapunov functionals in the framework of the input delay approach. The new Lyapunov functional is continuous at sampling times but not necessarily positive definite inside the sampling intervals. Compared w...\",\n \"Title: Input-to-state stability and integral input-to-state stability of nonlinear impulsive systems with delays\\nYear: 2009\\n\\nAbstract: This paper is concerned with analyzing input-to-state stability (ISS) and integral-ISS (iISS) for nonlinear impulsive systems with delays. Razumikhin-type theorems are established which guarantee ISS/iISS for delayed impulsive systems with external input affecting both the continuous dynamics and the discrete dynamics. It is shown that when the delayed continuous dynamics are ISS/iISS but the discrete dynamics governing the impulses are not, the ISS/iISS property of the impulsive system can be retained if the length of the impulsive interval is large enough. Conversely, when the delayed continuous dynamics are not ISS/iISS but the discrete dynamics governing the impulses are, the impulsive system can achieve ISS/iISS if the sum of the length of the impulsive interval and the time delay is small enough. In particular, when one of the delayed continuous dynamics and the discrete dynamics are ISS/iISS and the others are stable for the zero input, the impulsive system can keep ISS/iISS no matter how often the impulses occur. Our proposed results are evaluated using two illustrative examples to show their effectiveness.\",\n \"Title: Delay-dependent output feedback guaranteed cost control for uncertain time-delay systems\\nYear: 2004\\n\\nAbstract: This paper considers the problem of output-feedback guaranteed cost controller design for uncertain time-delay systems. By representing the time-delay system in the descriptor form and using a recent result on bounding of cross products of vectors, we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost output-feedback controller in terms of matrix inequalities. A numerical algorithm is proposed to construct a full order output feedback controller achieving a suboptimal guaranteed cost such that the system can be stabilized for all admissible uncertainties. An example is presented which shows that the proposed method can produce a lower guaranteed cost than the delay-independent method.\",\n \"Title: Global exponential stability of impulsive neural networks with variable delay: an LMI approach\\nYear: 2009\\n\\nAbstract: This paper focuses on the problem of global exponential stability analysis of impulsive neural networks with variable delay. Three types of impulses are considered: the impulses are input disturbances; the impulses are \\\"neutral\\\" type (that is, they are neither helpful for stability of neural networks nor destabilizing); and the impulses are stabilizing. For each type of impulses, by using Lyapunov function and Razumikhin-type techniques, the sufficient conditions for global exponential stability are developed in terms of linear matrix inequalities with respect to suitable classes of impulse time sequences. The new sufficient stability conditions do not impose any restriction on the size of time-delay. Numerical examples are given which show our results are less conservative than the existing sufficient stability conditions.\",\n \"Title: Improved delay-dependent asymptotic stability criteria for delayed neural networks.\\nYear: 2008\\n\\nAbstract: This brief is concerned with asymptotic stability of neural networks with uncertain delays. Two types of uncertain delays are considered: one is constant while the other is time varying. The discretized Lyapunov-Krasovskii functional (LKF) method is integrated with the technique of introducing the free-weighting matrix between the terms of the Leibniz-Newton formula. The integrated method leads to the establishment of new delay-dependent sufficient conditions in form of linear matrix inequalities for asymptotic stability of delayed neural networks (DNNs). A numerical simulation study is conducted to demonstrate the obtained theoretical results, which shows their less conservatism than the existing stability criteria.\",\n \"Title: An Improved Stabilization Method for Sampled-Data Control Systems With Control Packet Loss.\\nYear: 2012\\n\\nAbstract: This technical note presents a new method for stability analysis and stabilization of sampled-data systems with control packet loss. It is assumed that if the control packet from the controller to the actuator is lost, then the actuator input to the plant is set to zero. The new method is based on a novel construction of piecewise differentiable Lyapunov functionals by using an impulsive system representation of sampled-data systems. A significant feature of the new Lyapunov functionals is that they are continuous at impulse times but not necessarily positive definite inside the impulse intervals. Applying the new Lyapunov functionals to sampled-data systems with control packet loss, improved criteria for stability and stabilization are derived. The new criteria are proved theoretically to be less conservative than the existing results. Illustrative examples are given which substantiate the usefulness of the proposed method. © 2011 IEEE.\",\n \"Title: Stability analysis for switched systems with time-varying delay and parametric uncertainties\\nYear: 2010\\n\\nAbstract: This paper addresses the stability problem for switched systems with time-varying delay and parametric uncertainties. The main idea is to construct new piecewise time-varying Lyapunov functionals/functions such that they are decreasing at switching time instants in spite of their discontinuity at those switching time instants. Then the constructed piecewise time-varying Lyapunov functionals/functions are used to derive sufficient conditions for the existence of delay-independent minimum dwell time, which guarantee the exponential stability of switched delay systems for any bounded delays. The theoretical findings are validated by an illustrative example.\",\n \"Title: On improved robust stabilization of uncertain systems with unknown input delay\\nYear: 2006\\n\\nAbstract: This paper investigates the robust stabilization problem for uncertain systems with unknown input delay based on the reduction method. Two types of the unknown input delay are considered: one is constant; the other is continuous and may vary fast. Sufficient matrix inequalities conditions for stabilizability of such systems are derived via Lyapunov functionals and the descriptor system approach to time-delay systems. An algorithm involving convex optimization is proposed to design a delayed state feedback controller such that the system can be stabilized for all admissible uncertainties. Two illustrative examples are presented to show the effectiveness of the proposed algorithm.\",\n \"Title: Stability analysis for time-delay systems with partial states subject to impulsive inputs\\nYear: 2009\\n\\nAbstract: In practice, there exist such controlled systems in which some states are often not available, not measurable or too expensive to measure. For such systems, impulsive control inputs may be exerted on the available partial states so as to stabilize the underlying systems. This paper is concerned with analyzing the stability of a class of nonlinear time-delay systems with partial states subject to impulsive inputs. The main idea is that the entire impulsively controlled system can be viewed as a hybrid one that is composed of a stable continuous subsystem and a stable impulsive subsystem. Then the analysis technique based on the new time-varying weighted Lyapunov functional/function introduced is utilized to derive sufficient conditions for exponential stability of such systems. As an illustration of the utility of the new stability criteria, the batch reactor system with the try-once-discard protocol is examined.\",\n \"Title: Delayed Impulsive Control of Takagi–Sugeno Fuzzy Delay Systems\\nYear: 2013\\n\\nAbstract: In this paper, the problem of exponential stability for Takagi–Sugeno (T–S) fuzzy delay systems with delayed impulses is addressed. By means of the time-dependent Lyapunov function method combined with Razumikhin technique, a sufficient condition expressed in terms of linear matrix inequalities (LMIs) is obtained for exponential stability of T–S fuzzy delay systems with delayed impulses. The derived stability condition depends both on the lower bound and the upper bound of impulsive intervals, which is robust with respect to small impulse input delays. By solving a set of LMIs, an impulsive state feedback controller can be easily constructed. Two numerical examples are discussed to illustrate the effectiveness of the theoretical findings.\",\n \"Title: Asymptotic Stability in a Neutral Delay Differential System with Variable Delays\\nYear: 2006\\n\\nAbstract: By applying M-matrix theory and some new analysis techniques, we have succeeded in establishing the asymptotic stability of the zero solution of the \\\"pure-delay type\\\" neutral system with variable delays. The criteria obtained in this paper extend and improve the existing ones.\",\n \"Title: Delay-dependent guaranteed cost control for uncertain discrete-time systems with both state and input delays\\nYear: 2004\\n\\nAbstract: This paper considers the guaranteed cost control problem for a class of uncertain linear discrete-time systems with both state and input delays. By representing the time-delay system in the descriptor system form and using a recent result on bounding of cross products of vectors, we obtain new delay-dependent sufficient conditions for the existence of the guaranteed cost controller in terms of linear matrix inequalities. Numerical examples are presented which shows that the proposed method can even produce a lower guaranteed cost than the delay-independent methods.\",\n \"Title: A study of exponential stability for stochastic delayed neural networks\\nYear: 2010\\n\\nAbstract: This paper is concerned with analyzing mean square exponential stability of stochastic delayed neural networks subject to parametric uncertainties. The discretized Lyapunov functional technique is first utilized to construct a new Lyapunov functional in order to effectively deal with the time-varying delay. Then the free-weighting matrix technique and the convex combination method are used to establish a new delay-dependent mean square exponential stability criterion for uncertain stochastic delayed neural networks. The usefulness of the new theoretical findings is further demonstrated by numerical results.\",\n \"Title: Impulsive observers with variable update intervals for Lipschitz nonlinear time-delay systems\\nYear: 2013\\n\\nAbstract: This article is concerned with the design of impulsive observers with variable update intervals for Lipschitz nonlinear systems with delays in state. Discontinuous Lyapunov function/funtional approaches are developed to analyse the stability of error dynamics. Delay-independent sufficient conditions for uniform exponential stability of the error dynamics over variable update intervals are derived in terms of linear matrix inequalities LMIs. When these LMIs are feasible, the observer gain matrix can be solved numerically with an LMI-based optimisation algorithm. Numerical examples are provided to show the efficiency of the proposed approach.\",\n \"Title: Delay-dependent stability and H∞ control of uncertain discrete-time Markovian jump systems with mode-dependent time delays\\nYear: 2004\\n\\nAbstract: This paper considers the problems of stability, stabilization and H∞ control via memoryless state feedback for uncertain discrete-time Markovian jump linear systems with mode-dependent time delays. Based on linear matrix inequalities, delay-dependent solutions are obtained by using a descriptor model transformation of the system and by applying a new bounding technique for cross terms. Numerical examples are presented to illustrate the usefulness of the theoretical results.\",\n \"Title: Delay-dependent robust stabilization for uncertain neutral systems with distributed delays\\nYear: 2007\\n\\nAbstract: The problems of robust stability and robust stabilization of uncertain neutral systems with distributed delays are studied in this paper. Using a combination of integral inequality technique and descriptor system approach, new delay-dependent sufficient conditions for robust stability and robust stabilization are formulated in terms of linear matrix inequalities (LMIs). LMI-based conditions are also derived for robust stability and robust stabilizability of uncertain distributed-delay systems when the distributed delay belongs to a given interval. When the results obtained in this paper are applied to stabilization of combustion in the chamber of a liquid monopropellant rocket motor, it is found that the combustion can be robustly stabilized over larger variation intervals of pressure parameter and time-delay parameter than those obtained in Zheng and Frank [(2002). Robust control of uncertain distributed delay systems with application to the stabilization of combustion in rocket motor chambers. Automatica, 38, 487–497].\",\n \"Title: On Global Asymptotic Stability of Cohen–Grossberg Neural Networks With Variable Delays\\nYear: 2008\\n\\nAbstract: This paper studies the problems of existence, uniqueness, global asymptotic stability and global exponential stability of the equilibrium of Cohen-Grossberg neural networks with variable delays. An estimation technique based on delay differential inequality with variable coefficients is developed to establish delay-independent/delay-dependent sufficient conditions for global asymptotic/exponential stability. The stability criteria obtained are based on the M-matrix theory. These criteria can be easily checked in practice and do not require that the delays be constant or differentiable. In particular, our delay-independent asymptotic/exponential stability criteria remove a restriction on the amplification functions imposed by the existing results. Furthermore, our delay-dependent exponential stability criteria give explicitly the allowable upper bound on the diagonal delays such that the global stability property of Cohen-Grossberg neural networks can be retained. Thus, our new results are of great importance in design and application of Cohen-Grossberg neural networks with variable delays. The effectiveness of the new results is further illustrated by two numerical examples in comparison with the existing results.\",\n \"Title: Delay-Dependent Exponential Stability of Neural Networks With Variable Delay: An LMI Approach\\nYear: 2006\\n\\nAbstract: This brief focuses on the problem of delay-dependent stability analysis of neural networks with variable delay. Two types of variable delay are considered: one is differentiable and has bounded derivative; the other one is continuous and may vary very fast. By introducing a new type of Lyapunov-Krasovskii functional, new delay-dependent sufficient conditions for exponential stability of delayed neural networks are derived in terms of linear matrix inequalities. We also obtain delay-independent stability criteria. Two examples are presented which show our results are less conservative than the existing stability criteria.\",\n \"Title: Stability analysis of delayed cellular neural networks with impulsive effects.\\nYear: 2011\\n\\nAbstract: This paper focuses on the problem of exponential stability analysis of delayed cellular neural networks (DCNNs) with impulsive effects. The time delay is allowed to be time varying. By utilizing the piecewise linear property of the activation function of DCNNs and applying Razumikhin-type analysis techniques, two different types of delay-independent criteria for exponential stability of DCNNs with...\",\n \"Title: Global asymptotic stability of a class of neural networks with distributed delays\\nYear: 2006\\n\\nAbstract: In this paper, the problem of stability analysis for a class of neural networks with distributed delays is investigated. Applying the M-matrix theory and new analysis technique, novel sufficient conditions for the existence, uniqueness, and global asymptotic stability of the equilibrium point of neural networks with distributed delays are derived. The new stability criteria can be applied to the case when the nondelayed terms cannot dominate the delayed terms, which have great significance in the design and application of neural networks with distributed delays. Three illustrative examples are presented which demonstrate the usefulness of the proposed results\",\n \"Title: Guaranteed cost control for uncertain markovian jump systems with mode-dependent time-delays\\nYear: 2003\\n\\nAbstract: This note concerns the robust guaranteed cost control problem for a class of continuous-time Markovian jump linear system with norm-bounded uncertainties and mode-dependent time-delays. The problem is to design a memoryless state feedback control law such that the closed-loop system is stochastically stable and the closed-loop cost function value is not more than a specified upper bound for all admissible uncertainties. Based on linear matrix inequality, delay-dependent sufficient conditions for the existence of such controller are derived by using a descriptor model transformation of the system and by applying Moon's inequality for bounding cross terms. Sufficient conditions which depend on the difference between the largest and the smallest time-delays are also presented. Two numerical examples are given for illustration of the proposed theoretical results.\",\n \"Title: Input-to-state stability for networked control systems via an improved impulsive system approach\\nYear: 2011\\n\\nAbstract: This paper presents a novel impulsive system approach to input-to-state stability (ISS) analysis of networked control systems (NCSs) with time-varying sampling intervals and delays. This approach is based upon the new idea that an NCS can be viewed as an interconnected hybrid system composed of an impulsive subsystem and an input delay subsystem. A new type of time-varying discontinuous Lyapunov-Krasovskii functional, which makes full use of the information on the piecewise-constant input and the bounds of the network delays, is introduced to analyze the ISS property of NCSs. Linear matrix inequality based sufficient conditions are derived for ISS of NCSs with respect to external disturbances. When applied to the approximate tracking problem for NCSs, the derived ISS result provides bounds on the steady-state tracking error. Numerical examples are provided to show the efficiency of the proposed approach.\",\n \"Title: A new method for complete stability analysis of cellular neural networks with time delay.\\nYear: 2010\\n\\nAbstract: This paper presents new complete stability results for delayed cellular neural networks (DCNNs). A novel method is proposed for complete stability analysis of DCNNs. By applying the M-matrix theory and introducing some new estimation techniques on the solutions of DCNNs, a simple and improved complete stability criterion is derived. The new criterion unifies the delay-dependent and delay-independent complete stability conditions for DCNNs. Moreover, the obtained delay-dependent criterion can give a larger upper bound of the time delay than the existing ones such that the complete stability can still be retained. Numerical examples are presented which show that the new complete stability results for DCNNs are compared favorably with the existing results.\",\n \"Title: Delay-dependent stability and stabilizability of uncertain jump bilinear stochastic systems with mode-dependent time-delays\\nYear: 2005\\n\\nAbstract: This paper considers the problems of robust stability and robust stabilizability for a class of uncertain jump bilinear stochastic systems with mode-dependent time delays. By transforming the jump system under consideration into an equivalent descriptor jump system, a new stochastic Lyapunov functional is introduced for stability analysis and control design. Novel delay-dependent sufficient conditions in terms of linear matrix inequalities are derived for robust stability and robust stabilizability. Two numerical examples are given for the illustration of the proposed theoretical results.\",\n \"Title: Robust stability analysis for stochastic neural networks with time-varying delay.\\nYear: 2010\\n\\nAbstract: This brief investigates the problem of mean square exponential stability of uncertain stochastic delayed neural networks (DNNs) with time-varying delay. A novel Lyapunov functional is introduced with the idea of the discretized Lyapunov-Krasovskii functional (LKF) method. Then, a new delay-dependent mean square exponential stability criterion is derived by applying the free-weighting matrix technique and by equivalently eliminating time-varying delay through the idea of convex combination. Numerical examples illustrate the effectiveness of the proposed method and the improvement over some existing methods.\",\n \"Title: Delay-Independent Minimum Dwell Time for Exponential Stability of Uncertain Switched Delay Systems.\\nYear: 2010\\n\\nAbstract: In this technical note, the problem of delay-independent minimum dwell time for exponential stability of uncertain switched delay systems is considered. Piecewise time-varying Lyapunov functionals/functions which are decreasing at switching times by construction are introduced to investigate exponential stability of switched delay systems with constant or time-varying delays. This type of delicately constructed Lyapunov functionals/functions can efficiently eliminate the jump phenomena of adjacent Lyapunov functionals/functions at switching times without imposing any restriction on the sizes of time-delays. By applying this type of Lyapunov functionals/functions, it is shown that if each subsystem is delay-independently exponentially stable, then under some conditions there exists a delay-independent minimum dwell time in the sense that the switched delay system with such minimum dwell time is exponentially stable irrespective of the sizes of the time-delays. Two numerical examples are provided to demonstrate the efficiency of the proposed approach.\",\n \"Title: Stability Analysis and H∞-Control of Delayed Neutral Stochastic Systems with Time-Varying Parameter Uncertainties\\nYear: 2006\\n\\nAbstract: This paper is concerned with studying robust stochastic stability, stabilization and H∞-control of uncertain neutral stochastic systems with time-delay. Under the assumption that parametric uncertainties are time-varying and norm-bounded, delay-dependent sufficient conditions expressed by linear matrix inequalities are derived for the problems of robust stochastic stability, stabilization and H∞-control of uncertain neutral stochastic systems with time-delay. The usefulness of the theoretical results is exemplified by two numerical examples\",\n \"Title: Impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks.\\nYear: 2015\\n\\nAbstract: This paper investigates the problems of impulsive stabilization and impulsive synchronization of discrete-time delayed neural networks (DDNNs). Two types of DDNNs with stabilizing impulses are studied. By introducing the time-varying Lyapunov functional to capture the dynamical characteristics of discrete-time impulsive delayed neural networks (DIDNNs) and by using a convex combination technique, new exponential stability criteria are derived in terms of linear matrix inequalities. The stability criteria for DIDNNs are independent of the size of time delay but rely on the lengths of impulsive intervals. With the newly obtained stability results, sufficient conditions on the existence of linear-state feedback impulsive controllers are derived. Moreover, a novel impulsive synchronization scheme for two identical DDNNs is proposed. The novel impulsive synchronization scheme allows synchronizing two identical DDNNs with unknown delays. Simulation results are given to validate the effectiveness of the proposed criteria of impulsive stabilization and impulsive synchronization of DDNNs. Finally, an application of the obtained impulsive synchronization result for two identical chaotic DDNNs to a secure communication scheme is presented.\",\n \"Title: Global exponential stability of a class of impulsive neural networks with unstable continuous and discrete dynamics.\\nYear: 2015\\n\\nAbstract: This paper deals with global exponential stability of a class of impulsive neural networks whose continuous and discrete dynamics are unstable. Assuming that the impulsive neural network under consideration can be decomposed into two lower order impulsive systems, a time-varying weighted Lyapunov function associated with the impulse time sequence is introduced for stability analysis. A novel global exponential stability criterion is derived in terms of linear matrix inequalities (LMIs). By employing the newly obtained stability criterion, a sufficient condition on the existence of a reduced-order impulsive controller is derived. Unlike the previous results concerning impulsive control, the proposed reduced-order impulsive controller only exerts the impulses on a partial set of the state vector. Moreover, the controller gain matrices can be achieved by solving a set of LMIs. Finally, four illustrative examples are given to show the effectiveness of the developed techniques and results.\",\n \"Title: Global exponential stabilization of neural networks with time delay via impulsive control\\nYear: 2014\\n\\nAbstract: The problem of global exponential stabilization of discrete-time delayed neural networks (DDNNs) via impulsive control is addressed in this paper. A novel time-varying Lyapunov functional is proposed to capture the dynamical characteristic of discrete-time impulsive delayed neural networks (DIDNNs). In conjunction with the convex combination technique, new conditions in the form of linear matrix inequalities are established for global exponential stability of DIDNNs. The distinct features of the new stability conditions for DIDNNs are that they are dependent upon the lengths of impulsive intervals but independent of the size of time delay. This paves the way for designing the impulsive controller for impulsive stabilization of DDNNs. The applicability of the developed global exponential stabilization conditions is validated by numerical results.\",\n \"Title: Impulsive Synchronization of Reaction-Diffusion Neural Networks With Mixed Delays and Its Application to Image Encryption.\\nYear: 2016\\n\\nAbstract: This paper presents a new impulsive synchronization criterion of two identical reaction-diffusion neural networks with discrete and unbounded distributed delays. The new criterion is established by applying an impulse-time-dependent Lyapunov functional combined with the use of a new type of integral inequality for treating the reaction-diffusion terms. The impulse-time-dependent feature of the pro...\",\n \"Title: Robust sampled-data H∞ control of uncertain singularly perturbed systems using time-dependent Lyapunov functionals\\nYear: 2015\\n\\nAbstract: In this paper, the problem of robust sampled-data H∞ control of linear uncertain singularly perturbed systems is investigated. The parametric uncertainties are assumed to be time-varying and norm-bounded. Two types of controller design are considered: 1 with a fast sampling in the fast state and a slow one in the slow state, and 2 with a fast sampling in both states. For each type, a time-dependent Lyapunov functional associated with the sampling pattern is introduced to analyse the exponential stability and L2-gain performance of the closed-loop system. Linear matrix inequalities based solutions of the robust sampled-data H∞ control problem are derived. The new results are proved theoretically to be less conservative than the existing results. An illustrative example is given which substantiates the usefulness of the proposed method.\",\n \"Title: Periodically Intermittent Stabilization of Delayed Neural Networks Based on Piecewise Lyapunov Functions/Functionals\\nYear: 2014\\n\\nAbstract: This paper is concerned with the stabilization problem of delayed neural networks via a periodically intermittent controller. Two cases of time-varying bounded delays are considered: one is the time-varying delay without any constraints on the delay derivative, while the other is the time-varying delay with the delay derivative less than 1. For the first case, a piecewise time-invariant Lyapunov function-based method is applied, and the derived stability criterion improves an existing result. For the second case, a piecewise time-varying Lyapunov functional is introduced to establish a new stability criterion. Then, the obtained stability criteria are employed to design periodically intermittent controllers. Finally, two numerical examples are provided to illustrate the merits of the proposed approach.\",\n \"Title: Multistability in a class of stochastic delayed Hopfield neural networks.\\nYear: 2015\\n\\nAbstract: In this paper, multistability analysis for a class of stochastic delayed Hopfield neural networks is investigated. By considering the geometrical configuration of activation functions, the state space is divided into 2(n)+1 regions in which 2(n) regions are unbounded rectangles. By applying Schauder's fixed-point theorem and some novel stochastic analysis techniques, it is shown that under some conditions, the 2(n) rectangular regions are positively invariant with probability one, and each of them possesses a unique equilibrium. Then by applying Lyapunov function and functional approach, two multistability criteria are established for ensuring these equilibria to be locally exponentially stable in mean square. The first multistability criterion is suitable to the case where the information on delay derivative is unknown, while the second criterion requires that the delay derivative be strictly less than one. For the constant delay case, the second multistability criterion is less conservative than the first one. Finally, an illustrative example is presented to show the effectiveness of the derived results.\",\n \"Title: Globally exponential stabilization of neural networks with mixed time delays via impulsive control\\nYear: 2015\\n\\nAbstract: The impulsive stabilization problem of neural networks with discrete time-varying delays and unbounded continuously distributed delays is considered. By using impulse-time-dependent Lyapunov function-based techniques to capture the hybrid structure characteristics of the considered impulsive neural networks, two novel global exponential stability criteria are obtained in terms of linear matrix inequalities, which are capable of dealing with the case where both the continuous and discrete dynamics are unstable. When the original continuous-time delayed neural networks are not stable, sufficient conditions are developed for the design of exponentially stable linear impulsive state feedback controllers. Four numerical examples are given to illustrate the less conservatism and effectiveness of the proposed results.\",\n \"Title: Adaptive impulsive observers for nonlinear systems: Revisited\\nYear: 2015\\n\\nAbstract: This paper revisits the design of adaptive impulsive observers (AIOs) for nonlinear systems. The dynamics of observer state of the proposed AIO is modelled by an impulsive differential equation, by which the observer state is updated in an impulsive fashion. The parameter estimation law is modelled by an impulse-free time-varying differential equation associated with the impulse time sequence for determining when the observer state is updated. Unlike the previous work, the convergence analysis of the estimation error system is performed by applying a time-varying Lyapunov function based method, in conjunction with the application of a generalized version of Barbalat’s Lemma. A sufficient condition for the existence of AIOs is also derived. For some special cases, it is shown that the sufficient condition can be formulated in terms of linear matrix inequalities (LMIs), and the observer matrices can be attained by solving a set of LMIs. Furthermore, with an additional persistence-of-excitation-type constraint, it is proved that the sufficient condition can guarantee the convergence of parameter estimation. Two examples of chaotic oscillators are provided to illustrate the design procedure of the proposed AIOs.\",\n \"Title: Delay-independent stabilization of a class of time-delay systems via periodically intermittent control.\\nYear: 2016\\n\\nAbstract: The problem of delay-independently periodically intermittent stabilization for a class of time-delay systems is examined. First, the stability of the considered periodically intermittently controlled time-delay systems is analyzed by using the piecewise switching-time-dependent Lyapunov function/functional. The introduced Lyapunov function/functional is nonincreasing at switching instants, which can guarantee the exponential stability of the considered systems irrespective of the sizes of the state delays. Next, based on the newly established stability criteria, sufficient conditions for the existence of delay-independently periodically intermittent state-feedback controllers are derived. Finally, two illustrative examples are presented to show the validity of the obtained results.\",\n \"Title: Aperiodically intermittent H∞ synchronization for a class of reaction-diffusion neural networks.\\nYear: 2017\\n\\nAbstract: In this paper, the intermittent H ∞ synchronization problem for a class of reaction-diffusion neural networks with Dirichlet boundary conditions is investigated. Different from the previous works concerning intermittent synchronization, it is assumed that the response system is subject to external disturbance, and both the control period and the control width may be variable. A switching-time-dependent Lyapunov function combined with the use of the extended Wiritinger's inequality for exploring the stabilizing role of the reaction-diffusion term is employed to analyze the exponential stability and L2-gain performance of the synchronization error dynamics. In the framework of linear matrix inequalities, the aperiodically intermittent H ∞ synchronization controller is designed, which guarantees internally exponential stability as well as a prescribed L2-gain from the exogenous input to the regulated error output. Two numerical examples are given to illustrate the effectiveness of the proposed method.\",\n \"Title: Bipartite Consensus For Multiple Two-Time Scales Agents Over The Signed Digraph\\nYear: 2016\\n\\nAbstract: The bipartite consensus problem of multiple twotime scales agents over the signed digraph, where both cooperative and competitive interactions exist among the agents, is considered with a new distributed protocol. Sufficient conditions for bipartite consensus is presented in terms of easily checkable algebraic Riccati equation (ARE). Compared with the existing result on consensus of multiple two-time scales agents, the communication topology here is more generic. Moreover, the upper bound of the singular perturbation parameter is also presented. Simulation examples are given to illustrate the effectiveness of the proposed results.\",\n \"Title: Generating Globally Stable Periodic Solutions of Delayed Neural Networks With Periodic Coefficients via Impulsive Control.\\nYear: 2017\\n\\nAbstract: This paper is dedicated to designing periodic impulsive control strategy for generating globally stable periodic solutions for periodic neural networks with discrete and unbounded distributed delays when such neural networks do not have stable periodic solutions. Two criteria for the existence of globally exponentially stable periodic solutions are developed. The first one can deal with the case w...\",\n \"Title: Impulsive stabilization of a class of singular systems with time-delays.\\nYear: 2017\\n\\nAbstract: This paper deals with the impulsive stabilization problem for a class of linear singular systems with time-delays. The stabilization is achieved by only exerting impulsive action on the slow state variables. Two novel Lyapunov methods are presented to determine exponential stability of the impulsively controlled systems. For the case where the time-delay is unknown and may be time-varying, a Lyapunov–Razumikhin method is developed, in which the Razumikhin condition is constructed by exploiting the relation among the fast state variables, the slow state variables, and their initial values. For the case where the delay derivative is strictly less than 1, a descriptor type of impulse-time-dependent Lyapunov functional is introduced, which is discontinuous at impulse times but does not grow along the state trajectories by construction. By using a convex technique, the stability criteria are expressed in terms of linear matrix inequalities (LMIs). Then, the impulsive controllers can be designed in the framework of LMIs. The effectiveness and advantages of the proposed methods are confirmed through simulation results.\",\n \"Title: Impulsive H∞ synchronization for reaction-diffusion neural networks with mixed delays.\\nYear: 2018\\n\\nAbstract: This paper presents a study on impulsive H∞ synchronization analysis of reaction–diffusion neural networks with discrete and distributed delays. It is assumed that the output information of the drive system is only available at discrete instants, and the dynamics of the response system are subject to external disturbance. To achieve H∞ synchronization, an impulsive synchronization strategy is proposed which is based on feedback from the sampled-data of the drive and response dynamics. Novel time-dependent Lyapunov function/functional methods are developed for L2-gain analysis of synchronization error systems, both for fast-varying delays and for slowly-varying delays. LMI-based optimization methods are suggested to design impulsive H∞ synchronization controllers with minimized feedback gain. Numerical simulations are provided to validate the effectiveness of the theoretical results.\",\n \"Title: Stability and L2-gain analysis for impulsive delay systems: An impulse-time-dependent discretized Lyapunov functional method.\\nYear: 2017\\n\\nAbstract: The problems of exponential stability and L2-gain for a class of time-delay systems with impulsive effects are studied. The main tool used is the construction of an impulse-time-dependent complete Lyapunov functional. By dividing the impulse interval and delay interval into several segments, the matrix functions of this functional are chosen to be continuous piecewise linear. Moreover, an impulse-time-dependent weighting factor is introduced to coordinate the dynamical behavior of the nondelayed and integral terms of this functional along the trajectories of the system. By applying this functional, delay-dependent sufficient conditions for exponential stability and L2-gain are derived in terms of linear matrix inequalities. As by-products, new delay-independent sufficient conditions for the same problems are also derived. The efficiency of the proposed results is illustrated by numerical examples.\",\n \"Title: Modulus Consensus In A Network Of Singularly Perturbed Systems With Collaborative And Antagonistic Interactions\\nYear: 2017\\n\\nAbstract: This paper addresses the modulus consensus in a network of singularly perturbed systems, all of which own multi-time scales characteristics. The interactions among the agents are collaborative and antagonistic interactions, and it can been modelled by a signed directed graph. Also, the effect of time-varying delay has been taken into account when modelling the agent dynamics. Based on singularly perturbed decomposition method, Kronecker product technique and the comparison principle, several sufficient conditions are presented under which networked singularly perturbed time-varying delay systems with collaborative and antagonistic interactions achieve modulus consensus. Moreover, the upper bound of singular perturbation parameter is deduced explicitly. Two simulation examples are presented to illustrate the validity of the proposed results.\",\n \"Title: On Stabilization Of Delayed Linear Singular Systems Via Impulsive Control\\nYear: 2017\\n\\nAbstract: This paper is concerned with the stability problem of a class of delayed linear singular systems based on impulsive control. The key idea is to develop two novel Lyapunov methods to effectively deal with two different cases of delays: fast time-varying delay and slow time-vary delay. These Lyapunov methods take good advantage of the hybrid structure characteristics of the impulsively controlled singular systems so as to establish exponential stability of the underlying singular systems. A convex technique is applied to represent the derived stability conditions within the linear matrix inequalities framework, which facilitates design of the desired impulsive controllers. An illustrative example is given to substantiate the efficiency of the developed exponential impulsive stabilization conditions.\",\n \"Title: Sampled-data distributed H∞ control of a class of 1-D parabolic systems under spatially point measurements.\\nYear: 2017\\n\\nAbstract: This paper considers the sampled-data distributed H∞ control problem for 1-D semilinear transport reaction equations with external disturbances. It is assumed that a finite number of point spatial state measurements are available. A Razumikhin-type approach is developed for stability and L2-gain analysis of the closed-loop system. In contrast to Halanay׳s inequality based approach, the proposed Razumikhin-type approach not only provides a subtle decay estimate of the selected Lyapunov functional, but also guarantees the H∞ performance index to be negative if certain conditions are satisfied. By introducing a time-dependent Lyapunov functional combined with the use of Wirtinger׳s inequality, sufficient conditions for the internal exponential stability and finite L2-gain are derived in terms of linear matrix inequalities. The obtained conditions establish a quantitative relation among the upper bounds on the spatial sampling intervals and the time sampling intervals, and L2-gain. Two numerical examples are provided to illustrate the usefulness of the proposed theoretical results.\",\n \"Title: Multiple switching-time-dependent discretized Lyapunov functions/functionals methods for stability analysis of switched time-delay stochastic systems.\\nYear: 2018\\n\\nAbstract: This paper presents novel approaches for stability analysis of switched linear time-delay stochastic systems under dwell time constraint. Instead of using comparison principle, piecewise switching-time-dependent discretized Lyapunov functions/functionals are introduced to analyze the stability of switched stochastic systems with constant or time-varying delays. These Lyapunov functions/functionals are decreasing during the dwell time and non-increasing at switching instants, which lead to two mode-dependent dwell-time-based delay-independent stability criteria for the switched systems without restricting the stability of the subsystems. Comparison and numerical examples are provided to show the efficiency of the proposed results.\",\n \"Title: Disturbance-observer-based control design for a class of uncertain systems with intermittent measurement.\\nYear: 2017\\n\\nAbstract: The robust control problem of a class of uncertain systems subject to intermittent measurement as well as external disturbances is considered. The disturbances are supposed to be generated by an exogenous system, while the state information is assumed to be available only on some nonoverlapping time intervals. A composite design consisting of an intermittent state feedback controller augmented by a disturbance compensation term derived from a disturbance observer is formulated. Unlike the conventional disturbance observers, the proposed disturbance observer is modelled by a switched impulsive system, which makes use of the intermittent state data to estimate the disturbances. Stability analysis of the resulting closed-loop system is performed by applying a piecewise time-dependent Lyapunov function. Then a sufficient condition for the existence of the proposed composite controllers is derived in terms of linear matrix inequalities (LMIs). The controller and observer gains can be achieved by solving a set of LMIs. Further, a procedure to limit the norms of the controller and observer gains is given. Finally, an illustrative example is presented to demonstrate the validity of the results.\",\n \"Title: Impulsive effects on the stability and stabilization of positive systems with delays.\\nYear: 2017\\n\\nAbstract: •Exponential stability and positive stabilization for impulsive positive systems(IPSs) with delay are studied.•Three types of impulses are taken into consideration.•The Lyapunov–Razumikhin techniques are utilized for stability analysis.\",\n \"Title: A new method for global stability analysis of delayed reaction-diffusion neural networks.\\nYear: 2018\\n\\nAbstract: This paper presents improved criteria for global exponential stability of reaction–diffusion neural networks with time-varying delays. A novel diffusion-dependent Lyapunov functional, which is directly linked to the diffusion terms, is suggested to analyze the role of diffusivity of each neuron on the model dynamics. In the case of Dirichlet boundary conditions, the extended Wirtinger’s inequality is employed to exploit the stabilizing effect of reaction–diffusion terms. In the framework of descriptor system approach, the augmented Lyapunov functional technique is utilized to reduce the conservatism in the values of the time delay bounds. As a result, the derived global stability criteria are more effective than the existing ones. Three numerical examples are provided to illustrate the effectiveness of the proposed methodology.\",\n \"Title: Synchronization Analysis of Two-Time-Scale Nonlinear Complex Networks With Time-Scale-Dependent Coupling.\\nYear: 2019\\n\\nAbstract: In this paper, a time-scale-dependent coupling scheme for two-time-scale nonlinear complex networks is proposed. According to this scheme, the inner coupling matrices are related to the fast dynamics of individual subsystems, but are no longer time-scale-independent. Designing time-scale-dependent inner coupling matrices is motivated by the fact that the difference of time scales is an essential feature of modular architecture of two-time-scale systems. Under the novel coupling framework, the previous assumption on individual two-time-scale subsystems that the fast dynamics must be exponentially stable can be removed. The idea of time-scale separation is employed to analyze the stability of synchronization error systems via weighted ϵ-dependent Lyapunov functions. For a given upper bound of the singular perturbation parameter ϵ, it is proved that the exponential decay rate of the synchronization error can be guaranteed to be independent of the value of ϵ. In this way, criteria for local and global exponential synchronization are established. The allowable upper bound of ϵ such that the synchronizability of the considered two-time-scale network is retained can be obtained by solving a set of ϵ-dependent matrix inequalities. Finally, the efficiency of the proposed time-scale-dependent coupling strategy is demonstrated through numerical simulations.\",\n \"Title: Dissipativity of Singularly Perturbed Lur’e Systems\\nYear: 2019\\n\\nAbstract: The dissipativity problem of singularly perturbed Lur'e systems is investigated in this brief. Two new storage functions are constructed to explore the dynamics of both the fast and slow models, as well as their interaction more efficiently. By using the merit of the proposed storage functions, some new ε-uniformly strict dissipativity criteria in terms of well-conditioned linear matrix inequaliti...\",\n \"Title: Dynamic event-triggered control for linear stochastic systems with sporadic measurements and communication delays\\nYear: 2019\\n\\nAbstract: This paper deals with the stability of linear stochastic systems in the presence of sporadic measurements and communication delays. Motivated by considerations about the efficient use of the available resources, two so-called dynamic discrete-time event-triggered control (DTETC) strategies tailored to the system are designed, including some existing periodic event-triggered control strategies as particular cases. An impulsive switched system approach and a switched time-delay system approach are developed for modeling and stability analysis of the resulting closed-loop systems, respectively. In addition, it is shown that under the same decay rate, the designed dynamic DTETC may further reduce the conservatism than their static counterparts. Interestingly, the proposed impulsive switched system approach can capture the stabilizing effect of the communication delays. A numerical example is provided to illustrate the theoretical results.\",\n \"Title: New stability criteria for linear impulsive systems with interval impulse-delay\\nYear: 2021\\n\\nAbstract: The robust stability problem for linear time-delay systems with general linear delayed impulses is investigated. Different from the previous results, the impulse-delays are allowed to be larger than the impulse period. An auxiliary state variable is introduced to construct an augmented model of the impulsive system, under which the discrete dynamics introduced by impulse-delays can be highlighted. A novel piecewise Lyapunov functional is introduced to analyze the stability of the augmented model. This functional is continuous along the trajectories of the augmented model, and is not required to be positive-definite at non-impulse instants. LMI-based exponential stability conditions are derived, which depend on both the impulse-dwell-time and the impulse-delay-interval. Numerical examples show that the obtained stability criteria are able to handle the benefit/harmful impulse-delays.\",\n \"Title: A refined discretized timer-dependent Lyapunov functional for impulsive delay systems\\nYear: 2021\\n\\nAbstract: A new type of discretized Lyapunov functional is introduced for stability and hybrid L2×l2-gain analysis of linear impulsive delay systems. This functional consists of three parts. The first part is the conventional discretized functional for delay-independent stability analysis. The second part is the looped-functionals-like functional for exploiting the internal structure inside impulse intervals, in which the decision matrix functions are approximated by piecewise linear matrix functions. The third part is a discretized adjustive factor, which makes the proposed Lyapunov functional continuous along the system trajectories. Thanks to this continuity, the resultant criteria for exponential stability and finite hybrid L2×l2-gain are expressed in terms of a combination of the continuous and discrete parts of the system. It is shown through numerical examples that the accuracy of the stability test increases with the increase of the partition number on impulse intervals, and the convergence rate is faster than that of the previous discretized functionals-based approach.\",\n \"Title: Impulsive average-consensus of multi-agent systems with time-delays\\nYear: 2022\\n\\nAbstract: In this paper, the impulsive average-consensus problem of first-order multi-agent systems with dynamically changing topologies is investigated. Continuous-time dynamics and impulsive protocols are both subjected to effects from nonuniform time-varying communication delays. By utilizing Razumikhin techniques and time-varying Lyapunov function method, some impulse-delay-dependent sufficient criteria for the average-consensus of multi-agent systems are derived. In addition, the discrete-time connection digraph is designed in terms of linear matrix inequalities for given impulsive sequences and some programming skills are used to make the discrete-time topology meet the needs of the actual environment. Numerical simulations are given to illustrate the effectiveness and validity of the theoretical results.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":59,"string":"59"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13365,"string":"13,365"}}},{"rowIdx":13366,"cells":{"question_id":{"kind":"string","value":"Jang Ping Sheu"},"question":{"kind":"string","value":"Generate an abstract for the title \"A traveling salesman mobility model and its location tracking in PCS networks\" using the following items: 1. Location tracking\n2. PCS networks\n3. Traveling salesman mobility (TSM) model\n4. Mobility patterns\n5. Prospective strategy."},"answer":{"kind":"string","value":"This paper considers the location tracking problem in PCS networks. How a solution to this problem performs in fact highly, depends on the mobility patterns of users. In this paper we propose a new traveling salesman mobility (TSM) model, in the hope of catching the mobility patterns of a large group of users. The TSM model is characterized by features of “stop-or-move”, “infrequent transition” “memory of roaming direction”, and “oblivious in different moves”. Then a location tracking strategy based on this TSM model is developed. The scheme only needs to keep very little information for each user. Analyses and simulations are provided, which show that the strategy is very prospective"},"correct_answer":{"kind":"string","value":"This paper considers the location tracking problem in PCS networks. How a solution to this problem performs in fact highly, depends on the mobility patterns of users. In this paper we propose a new traveling salesman mobility (TSM) model, in the hope of catching the mobility patterns of a large group of users. The TSM model is characterized by features of “stop-or-move”, “infrequent transition” “memory of roaming direction”, and “oblivious in different moves”. Then a location tracking strategy based on this TSM model is developed. The scheme only needs to keep very little information for each user. Analyses and simulations are provided, which show that the strategy is very prospective"},"documents":{"kind":"list like","value":["Title: Unilateral Wakeup for Mobile Ad Hoc Networks\nYear: 2011\n\nAbstract: Asynchronous wakeup schemes have been proposed for ad hoc networks to increase the energy efficiency of wireless communication. The basic idea is to allow a node to sleep when it is idle, and wakeup periodically to check if there are pending transmissions. In this paper we examine the applicability of asynchronous wakeup schemes to the Mobile Ad Hoc Networks (MANETs). We discover that, although it is desirable to have nodes with lower mobility to sleep more in reaction to the less-changing link states, in practice this is prohibited due to an unwanted tradeoff between the energy saving and in-time link discovery. All nodes in a network must stay awake frequently based on their highest possible moving speed in order to avoid network partition. To address this problem, we propose a new wakeup scheme, named Unilateral- (Uni-) scheme, for MANETs that allows nodes with slower moving speed to sleep more without losing the network connectivity. Theoretical analysis shows that the Uni-scheme can render up to 24% improvement in energy saving as compared with the previous arts.","Title: A priority MAC protocol to support real-time traffic in ad hoc networks\nYear: 2004\n\nAbstract: Carrier sense multiple access and its variants have been widely used in mobile ad hoc networks. However, most existing access mechanisms cannot guarantee quality for real-time traffic. This paper presents a distributed medium access control protocol that provides multiple priority levels for stations to compete for the wireless channel. One common channel is assumed to be shared by all stations. Stations are assumed to be able to hear each other (i.e., the network is fully connected). The channel is accessed by stations according to their priorities, and for stations with the same priority, they send frames in a round robin manner. The channel access procedure is divided into three stages: priorities classification period, ID initialization period, and transmission period. Simulation results indicate that our protocol provides high channel utilization and bounded delays for real-time frames.","Title: Load-Balanced Trees for Data Collection in Wireless Sensor Networks\nYear: 2012\n\nAbstract: In static wireless sensor networks, it is an important research issue to achieve effectively periodic data collection and prolong the network lifetime. In this paper, a distributed k-load-balanced tree scheme is proposed to prolong the network lifetime for periodic data collection. A k-load-balanced tree is a tree that the difference of the number of children of each two non-leaf nodes in a network is less than k. Each node chooses the node with the least current number of children and number of neighbor as parent for avoiding that the difference of the number of children of each two non-leaf nodes in a network is more than k. The simulation results show that our scheme can prolong the network lifetime and the network delay time is close to the result of centralized method.","Title: Seamless channel transition for the staircase video broadcasting scheme\nYear: 2004\n\nAbstract: In the literature, many broadcasting-based schemes have been proposed to efficiently support near-VOD services. However, none of these schemes allows the server to dynamically and seamlessly change the number of channels allocated to a video. Naively allocating a new set of channels for the transition could increase server's load, waste communication bandwidth, and even drain the channels of the system. In Tseng et al. (2000), it is shown how to enhance the Fast Broadcasting (FB) scheme for seamless channel transition. The problem remains open whether other broadcasting-based schemes can sustain seamless channel transition. In this paper, we show how to enhance the Staircase Broadcasting (SB) scheme so that a server can seamlessly increase or decrease the channels allocated to a video. The SB scheme has been proved to require significantly less buffering space than FB, while sustaining the same startup latency as FB. Detailed performance comparisons are presented to demonstrate the advantages of the proposed scheme.","Title: A Distributed Query Protocol in Wireless Sensor Networks\nYear: 2007\n\nAbstract: In wireless sensor networks, query execution over a specific geographical region is an essential function for collecting sensed data. However, sensor nodes deployed in sensor networks have limited battery power. Hence, the minimum number of connected sensor nodes that covers the queried region in a sensor network must be determined. This paper proposes an efficient distributed protocol to find a subset of connected sensor nodes to cover the queried region. Each node determines whether to be a sensing node to sense the queried region according to its priority. The proposed protocol can efficiently construct a subset of connected sensing nodes and respond the query request to the sink node. In addition, the proposed protocol is extended to solve the k-coverage request. Simulation results show that our protocol is more efficient and has a lower communication overhead than the existing protocol.","Title: Data broadcasting and seamless channel transition for highly demanded videos\nYear: 2000\n\nAbstract: One way to broadcast a popular video is to use a number of dedicated channels, each responsible for broadcasting some portion of the video periodically in a predefined way. The stress on the channels can be alleviated, and new viewers do not have to wait long to start their playback. Many approaches falling in this category have been proposed. One such scheme that interests us is the fast broadcasting (FB) scheme, which can broadcast a video using k channels by incurring at most O(D/2k) waiting time on new-coming viewers, where D is the length of the video. We consider a set of videos, each being broadcast by the FB scheme. Since the demand levels on these videos may change with time, it is sometimes inevitable to change the numbers of channels assigned to some videos. We propose a novel seamless channel transition enhancement on top of the FB scheme to dynamically change the number of channels assigned to a video on-the-fly. Clients currently viewing this video will not experience any disruption because of the transition. A channel allocation scheme is also proposed based on the arrival rates of videos to minimize the average waiting experienced by all viewers. From the system manager's point of view, the enhancement will make the FB scheme more attractive","Title: Pair-wise path key establishment in wireless sensor networks\nYear: 2007\n\nAbstract: When sensor networks deployed in unattended and hostile environments, for securing communication between sensors, secret keys must be established between them. Many key establishment schemes have been proposed for large scale sensor networks. In these schemes, each sensor shares a secret key with its neighbors via preinstalled keys. But it may occur that two end nodes which do not share a key with each other could use a secure path to share a secret key between them. However during the transmission of the secret key, the secret key will be revealed to each node along the secure path. Several researchers proposed a multi-path key establishment to prevent a few compromised sensors from knowing the secret key, but it is vulnerable to stop forwarding or Byzantine attacks. To counter these attacks, we propose a hop by hop authentication scheme for path key establishment to prevent Byzantine attacks. Compared to conventional protocols, our proposed scheme can mitigate the impact of malicious nodes from doing a Byzantine attack and sensor nodes can identify the malicious nodes. In addition, our scheme can save energy since it can detect and filter false data not beyond two hops.","Title: An obstacle-free and power-efficient deployment algorithm for wireless sensor networks\nYear: 2009\n\nAbstract: This paper proposes a robot-deployment algorithm that overcomes unpredicted obstacles and employs full-coverage deployment with a minimal number of sensor nodes. Without the location information, node placement and spiral movement policies are proposed for the robot to deploy sensors efficiently to achieve power conservation and full coverage, while an obstacle surrounding movement policy is proposed to reduce the impacts of an obstacle upon deployment. Simulation results reveal that the proposed robot-deployment algorithm outperforms most existing robot-deployment mechanisms in power conservation and obstacle resistance and therefore achieves a better deployment performance.","Title: Increasing The Throughput Of Multihop Packet Radio Networks With Power Adjustment\nYear: 2001\n\nAbstract: The Packet Radio Network (PRN) is an attractive architecture to support mobile and wireless communication. Although the code assignment problem has been studied extensively on PRN, we observe in this paper that the power control problem has been ignored by most works, but may have significant impact on performance. By power control, we mean that the transmission ranges of stations are tunable. We show given a PRN in which each host already received a code, how to adjust the powers of stations to control/improve the topology of the PRN without violating the original code assignment. Several schemes are proposed. Through simulations, we demonstrate that although the code assignment problem is NP-complete and thus computationally very expensive, using our power adjustment schemes can easily improve the network performance by about 20% with polynomial costs.","Title: A Resource Allocation Scheme for Scalable Video Multicast in WiMAX Relay Networks\nYear: 2013\n\nAbstract: This paper proposes the first resource allocation scheme in the literature to support scalable-video multicast for WiMAX relay networks. We prove that when the available bandwidth is limited, the bandwidth allocation problems of 1) maximizing network throughput and 2) maximizing the number of satisfied users are NP-hard. To find the near-optimal solutions to this type of maximization problem in polynomial time, this study first proposes a greedy weighted algorithm, GWA, for bandwidth allocation. By incorporating table-consulting mechanisms, the proposed GWA can intelligently avoid redundant bandwidth allocation and thus accomplish high network performance (such as high network throughput or large number of satisfied users). To maintain the high performance gained by GWA and simultaneously improve its worst case performance, this study extends GWA to a bounded version, BGWA, which guarantees that its performance gains are lower bounded. This study shows that the computational complexity of BGWA is also in polynomial time and proves that BGWA can provide at least 1/ρ times the performance of the optimal solution, where rho is a finite value no less than one. Finally, simulation results show that the proposed BGWA bandwidth allocation scheme can effectively achieve different performance objectives with different parameter settings.","Title: Circuit-Switched Broadcast in Multi-Port 2D Tori\nYear: 1999\n\nAbstract: . This paper studies the one-to-all broadcast in a circuit-switched2D torus of any size with ff-port capability. This is a generalization of theone-port and all-port models. Existing results, as compared to ours, canonly solve very restricted sizes of tori, and use more numbers of steps.1 IntroductionOne primary communication in an interconnection network is the one-to-allbroadcast, where a source node needs to send a message to all other nodes inthe network. This paper studies the...","Title: Tolerating Faults in Faulty Hypercubes Using Maximal Fault-Free Subcube-Ring\nYear: 1995\n\nAbstract: In this paper, we present a reconfiguration approach to identify the maximalfault-free subcube-ring for tolerating faults in injured hypercubes. The fault-freesubcube-ring is connected by a ring of fault-free subcubes with dilation 3. By exploitingthe size of fault-free subcubes as large as possible, the maximal fault-freesubcube-ring with higher processor utilization is obtained. Using this approach,we can tolerate more than n faults in n-dimensional hypercubes. To demonstratethe...","Title: Ratio-based time synchronization protocol in wireless sensor networks\nYear: 2008\n\nAbstract: Time synchronization plays a key role in the wireless sensor networks (WSNs). Time synchronization is realized by those messages that are time-stamped. But there are several delay times during transmission after time stamping. Most of them are uncertain and contribute directly to synchronization error. The uncertainties include send time, channel access time, transmission time, and receive time. In addition to the uncertainties, clock drift is also a main source of time synchronization error. In this paper, we present a time synchronization protocol that can be applied in the multi-hop WSNs. The proposed protocol estimates the clock drift between two nodes to keep them synchronized for duration after once synchronizing. It uses lower communication overhead and establishes more robust synchronization situations for all nodes in the network. By periodical re-synchronization, the un-synchronization conditions such as nodes failures or topology change can be easily overcome. We implement our protocol in the Berkeley MICAz platform. The experimenting scenarios are 5-node and 18-node multi-hop topologies, and the re-synchronization periods are 30-second and 300-second. The experiment results show that the average synchronization errors of all nodes run with our protocol are ranged within several micro-seconds which are better than the previous protocol.","Title: Location-free topology control protocol in wireless ad hoc networks\nYear: 2007\n\nAbstract: Topology control emphasizes the proper adjustment of the transmission power of each node in wireless mobile ad hoc networks. It not only saves power but also increases the system throughput by increasing the spatial reuse of communication channels. However, there is a hidden terminal problem at the medium access control (MAC) layer if we merely address the topology control issue at the network layer. This paper proposes a distributed protocol that deals with topology control at the network layer and at the same time overcomes the hidden terminal problem at the MAC layer. Each node in the networks determines its power for data transmission and control packets transmission according to the received beacon messages from its neighbors. The proposed protocol works without location information and use little control packet overhead to prevent potential collisions due to hidden terminals. Simulations show that our protocol significantly decreases the total power consumption in the networks and has a better network throughput compared to other protocols.","Title: Routing with Hexagonal Virtual Coordinates in Wireless Sensor Networks\nYear: 2007\n\nAbstract: Using geographic routing, like GPSR, is efficient for ad hoc and wireless sensor networks, but it requires that nodes be aware of their physical positions. However, if there are holes in the network, routing across holes in GPSR will lead to a lot of overloaded nodes in the boundaries of the holes. In this paper, we propose a distributed protocol, named the hexagonal virtual coordinate (HVC), for constructing a virtual coordinate system. After the HVC is constructed, the nodes in the network will be aware of relative coordinates among the landmarks through the HVC chart. Based on the HVC chart, a source node can find an auxiliary routing path to indicate the direction of the journey from the source to the destination. Simulation results show that our protocol can support geographic routing efficiently.","Title: Selection of the first k largest processes in hypercubes\nYear: 1989\n\nAbstract: In this paper, algorithms are proposed for finding the first k largest numbered processes in hypercubes with and without faulty nodes.","Title: A load awareness medium access control protocol for single-hop wireless ad hoc networks\nYear: 2008\n\nAbstract: A contention-based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA-CA), has excellent efficiency when the system is light loaded. The main drawback of such protocols is their inefficiency and unbounded delay when the system load is heavy. On the other hand, a contention-free MAC protocol, such as token passing, has a better and fair throughput when the system is heavy loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness single-hop wireless ad hoc MAC protocol (which is called the LA protocol) that exploits the benefits of both contention-based and contention-free protocols. A contention-based MAC protocol is used when the system is light loaded and a contention-free one is used otherwise. Our LA protocol, which operates in a distributed fashion and is fully compatible with the IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention-based protocol and the contention-free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols. Copyright © 2006 John Wiley & Sons, Ltd.","Title: Scalable continuous object detection and tracking in sensor networks\nYear: 2010\n\nAbstract: With the advancement of MEMS technologies, sensor networks have opened up broad application prospects. An important issue in wireless sensor networks is object detection and tracking, which typically involves two basic components, collaborative data processing and object location reporting. The former aims to have sensors collaborating in determining a concise digest of object location information, while the latter aims to transport a concise digest to sink in a timely manner. This issue has been intensively studied in individual objects, such as intruders. However, the characteristic of continuous objects has posed new challenges to this issue. Continuous objects can diffuse, increase in size, or split into multiple continuous objects, such as a noxious gas. In this paper, a scalable, topology-control-based approach for continuous object detection and tracking is proposed. Extensive simulations are conducted, which show a significant improvement over existing solutions.","Title: GRID: A Fully Location-Aware Routing Protocol for Mobile Ad Hoc Networks\nYear: 2001\n\nAbstract: mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to assist routing in such an environment is to use location information provided by positioning devices such as global positioning systems (GPS). In this paper, we propose a new routing protocol called GRID, which tries to exploit location information in route discovery, packet relay, and route maintenance. Existing protocols, as compared to ours, are either not location-aware or partially location-aware in that location knowledge is not fully exploited in all these three aspects. One attractive feature of our protocol is its strong route maintenance capability --- the intermediate hosts of a route can perform a \"handoff\" operation similar to that in cellular systems when it roams away to keep a route alive. This makes routes in the MANET more stable and insensitive to host mobility. Simulation results show that our GRID routing protocol can reduce the probability of route breakage, reduce the number of route discovery packets used, and lengthen routes' lifetime.","Title: A distributed IP address assignment scheme in ad hoc networks\nYear: 2008\n\nAbstract: In this paper, we present a scheme to assign IP address to each newly-joined node. Some nodes are assigned as coordinators, and are responsible for assigning an IP address to a new node in the network. A new node will use the exchanged hello messages to find the closest coordinator and obtain a new IP address from that coordinator. In order to efficiently maintain the coordinators驴 IP-address pools, the distributed coordinators are organized in a tree topology, called a virtual C-tree, by exchanging hello messages. Simulation results show that our proposed scheme has a low latency for obtaining a new IP address, and that it can efficiently maintain consistent IP-address pools.","Title: Cache-Based Routing for Vehicular Ad Hoc Networks in City Environments\nYear: 2010\n\nAbstract: Most of routing protocols in VANETs are position-based due to their well scalability. The forwarding decisions of such protocols are simply based on the location information of forwarders' neighborhood and the destination node. Due to high mobility of vehicles, location-service protocols are required to provide the destination location. Location services protocols can be categorized as flooding-based and quorum-based. They are unrealistic for VANETs. In the former approaches, global network flooding require extreme high cost, while in the latter approaches, quorums' hand-off is impossible because of high volume of exchange data. In this paper, we present a routing by utilizing locality of vehicles' traces (i.e., left location information). Besides, by the aid of high mobility of vehicles and news exchange (new information about vehicles' location), vehicles' location information can be spread to improve the possibility of meeting a vehicle which has the location information of the destination. Our protocol is realistic and practical because neither global network flooding nor quorums are required. The simulation results show that our protocol works efficiently for VANETs in city environments and has higher successful query rate and lower cost.","Title: Balanced spanning trees in complete and incomplete star graphs\nYear: 1996\n\nAbstract: Efficiently solving the personalized broadcast problem in an interconnection network typically relies on finding an appropriate spanning tree in the network. In this paper, we show how to construct in a complete star graph an asymptotically balanced spanning tree, and in an incomplete star graph a near-balanced spanning tree. In both cases, the tree is shown to have the minimum height. In the literature, this problem has only been considered for the complete star graph, and the constructed tree is about 4/3 times taller than the one proposed in this paper","Title: Fault-tolerant parallel k selection algorithm in n-cube networks\nYear: 1991\n\nAbstract: In this paper, a parallel algorithm to select the first k largest numbered processes in n-cube networks is proposed. The proposed algorithm can tolerate at most n - 1 faults. The time complexity of this algorithm is 0(max(kn, n2)).","Title: Design and implementation of ad hoc classroom and eSchoolbag systems for ubiquitous learning\nYear: 2002\n\nAbstract: This paper describes the design and implementation of a learning technology project. The purpose of this project is to develop advanced wireless technologies for building an ad hoc classroom in order to contrive a modern and new learning environment. A wireless platform is developed for teacher and students to establish a classroom dynamically irrespective of location and time bounds. As supported in a traditional classroom, we develop information technology to provide the teacher with teaching aids, such as blackboard, board rubber, colored chalk, microphone, voice recorder, video recorder, and so on, for course teaching and discussions in an ad hoc classroom. In addition, we provide students with an electronic schoolbag (or eSchoolbag) which packs electronic book, notebook, parents contact book, pencil case, writing materials, sheets, calculator, address book, and so on. Taking lessons in a lively, vivid, and new learning environment, students are expected to enhance their learning performance without any burden like attending classes physically. Moreover students get more flexible scope of learning at a convenient time.","Title: Unilateral Wakeup for Mobile Ad Hoc Networks with Group Mobility\nYear: 2013\n\nAbstract: Asynchronous wakeup schemes have been proposed for ad hoc networks to increase the energy efficiency of wireless communication. The basic idea is to allow a node to sleep when it is idle, and wakeup periodically to check if there are pending transmissions. In this paper, we examine the applicability of asynchronous wakeup schemes to the Mobile Ad Hoc NETworks (MANETs). We discover that, although it is desirable to have nodes with lower mobility to sleep more in reaction to the less-changing link states, in practice this is prohibited due to an unwanted tradeoff between the energy saving and in-time link discovery. All nodes in a network must stay awake frequently based on their highest possible moving speed to avoid network partition. To address this problem, we propose a new wakeup scheme, named Unilateral- (Uni-) scheme, for MANETs that allows nodes with slower moving speed to sleep more without losing the network connectivity. The Uni-scheme supports both the entity mobility and group mobility of nodes, thus has broad applicability. Theoretical analysis and simulation are conducted and show that the Uni-scheme can render significant energy saving as compared with the previous arts.","Title: An on-demand, link-state, multi-path QoS routing in a wireless mobile ad-hoc network\nYear: 2004\n\nAbstract: The peer-to-peer multimedia applications have recently generated much interest in wireless network infrastructure with supporting the quality-of-service (QoS) communications. In this paper, we propose a new on-demand QoS routing, namely link-state multi-path QoS routing, protocol in a wireless mobile ad-hoc network (MANET). Our proposed scheme offers a bandwidth routing protocol for QoS support in a multihop mobile network. Our QoS routing protocol determines the end-to-end bandwidth calculation and bandwidth allocation at the destination. Our protocol collects link bandwidth information from source to destination in order to construct a network topology with the information of link bandwidth at the destination. To satisfy a given bandwidth requirement, the bandwidth calculation of the QoS route are determined at the destination to accurately determine the QoS uni-path or multi-path route depending on the status of network bandwidth. Our routing scheme may offer a multi-path route if a MANET with the insufficient network bandwidth, and provide a uni-path route if the network bandwidth is sufficient. The destination eventually determines the QoS multi-path routes and replies to the source host to perform the bandwidth reservation. Our routing scheme obviously improves the success rate of identifying a QoS route, and the simulation result demonstrates this improvement.","Title: Efficient path planning and data gathering protocols for the wireless sensor network\nYear: 2010\n\nAbstract: Wireless sensor network is commonly used to monitor certain region and to collect data for several applications. Normally, in wireless sensor network, data are routed in a multi-hop fashion towards a static sink. In this scenario, nodes closer to the sink become heavily involved in packet forwarding and their battery power is exhausted quickly. In this paper, an Infrastructure based Data Gathering Protocol (IDGP) and a Distributed Data Gathering Protocol (DDGP) are proposed to plan the data gathering path for a mobile sink. A k-hop relay mechanism is introduced to limit the number of hops for routing data to a mobile sink. In order to increase the efficiency of the data gathering, a cooperative environment among the sensor nodes and the mobile robot is proposed to formulate the data gathering path. Simulation results show that our data gathering protocols enable the nodes to transmit data with least number of hops and simultaneously reduce the data gathering path length traced by the mobile sink.","Title: Location-based IP assignment protocol for ad hoc networks\nYear: 2006\n\nAbstract: In this paper, we propose a location-based IP assignment protocol. We assume that a mobile host knows its current physical location; thus, this location information can be exploited to facilitate IP assignment. We divide the entire network into several disjoint and same-size cells and each cell has a coordinator to assign and maintain the available IP addresses. With location information for each host, the scheme proposed in this paper can avoid the problems of network partitions and mergers. Simulation results show the IP addresses can be fully utilized and that the control overhead and latency time are not affected by the mobility speed","Title: Partitioning and mapping of nested loops for linear array multicomputers\nYear: 1995\n\nAbstract: In distributed-memory multicomputers, minimizing interprocessor communication is the key to the efficient execution of parallel programs. In order to reduce the amount of communication overhead, parallel programs on multicomputers must be carefully scheduled by parallelizing compilers. This paper proposes some compilation techniques for partitioning and mapping nested loops with constant data dependences onto linear array multicomputers. First, a systematic partition strategy is proposed to project ann-dimensional computational structure, representing ann-nested loop, onto a line to form a one-dimensional projected structure with low communication overhead. Then, a mapping algorithm is proposed for mapping the partitioned loops onto linear arrays in a way that balances the workload and minimizes the communication cost among processors. Finally, parallel execution codes can be automatically generated for such linear array multicomputers.","Title: Efficient Single-Node Broadcast In Switched-Based Network Of Workstations With Network Partitioning\nYear: 2001\n\nAbstract: This paper proposes two efficient single-node broadcasting schemes for network of workstations (NOW) based on a network-partitioning concept. To broadcast a message, the scheme works in three phases. First, we partition the network into two sub-networks(data-distributed networks, DDN). The broadcast message is evenly divided into two sub-messages, each being sent to one representative node in each subnetwork. Second, each sub-message is distributed in its subnetwork independently. Finally, through a sub-message combination step, each node will obtain the whole broadcast message. Two network-partitioning schemes, namely 0-1 partitioning and odd-even partioning, are proposed. Through simulations on irregular and regular networks, we confirm the average latency of these schemes achieve performance improvement compared with the optimal broadcast scheme [7].","Title: An Anonymous Path Routing (APR) Protocol for Wireless Sensor Networks\nYear: 2011\n\nAbstract: How to secure data communication is an important problem in wireless sensor networks (WSNs). General solutions to the problem are to encrypt the packet payload with symmetric keys. But those solutions only prevent the packet content from being snooped or tampered. Adversaries still can learn of network topology by the traffic analysis attack for starting devastating attacks such as the denial-of-service attack and the like. In this paper, we propose an anonymous path routing (APR) protocol for WSNs. In APR, data are encrypted by pair-wise keys and transmitted with anonyms between neighboring sensor nodes and anonyms between the source and destination nodes of a multi-hop communication path. The encryption prevents adversaries from disclosing the data, and the anonymous communication prevents adversaries from observing the relation of the packets for further attacks. We implement APR on the MICAz platform to evaluate its overheads for demonstrating its applicability in practical WSNs.","Title: An Efficient Channel Allocation Technique for Multiple Videos-on-Demand\nYear: 2003\n\nAbstract: In this paper, we describe our work on developing an eLearning video database system. The eLearning video database provides a temporal modeling framework for describing eLearning video data and it supports data distribution by applying vertical class ...","Title: Adaptive route-sharing protocol for data collection in Wireless Sensor Networks\nYear: 2012\n\nAbstract: A Wireless Sensor Network (WSN) comprises a large number of sensor nodes and a few sink nodes. When multiple sink nodes are interested in collecting the readings of the same monitoring region, it is conducive to exploit the sharing route to save bandwidth and power consumption and prolong WSNs lifetime. This paper proposes a Dynamic Route-Sharing Protocol (DRSP), which constructs sharing routes based on different attributes (for example, frequency, packet length or delay time) of the commands requested from different sink nodes. The proposed DRSP dynamically adjusts data transmission route to achieve the goals of routes sharing and route length reduction. The simulation study shows that DRSP saves more energy and bandwidth consumptions than the existing work and thus prolongs the WSNs lifetime.","Title: Reducing Cache Conflicts by Multi-Level Cache Partitioning and Array Elements Mapping\nYear: 2000\n\nAbstract: This article presents an algorithm to reduce cache conflicts and improve cache localities. The proposed algorithm analyzes locality reference space for each reference pattern, partitions the multi-level cache into several parts with different sizes, and then maps array data onto the scheduled cache positions to eliminate cache conflicts. A greedy method for rearranging array variables in declared statement is also developed, to reduce the memory overhead for mapping arrays onto a partitioned cache. Besides, loop tiling and the proposed schemes are combined to exploit opportunities for both temporal and spatial reuse. Atom is used as a tool to develop a simulation of the behavior of the direct-mapping cache to demonstrate that our approach is effective at reducing number of cache conflicts and exploiting cache localities. Experimental results reveal that applying the cache partitioning scheme can greatly reduce the cache conflicts and thus save program execution time in both single-level cache and multi-level cache hierarchies.","Title: Data mapping of linear programming on fixed-size hypercubes\nYear: 1990\n\nAbstract: Although many solution methods are available for the linear programming problem, the simplex method is undoubtedly the most widely used one for its simplicity. In this paper, we propose an implementation of the simplex method on fixed-size hypercubes. A partitioning technique and a mapping technique are presented to fit large-size problem instances into relatively small-size hypercubes. Two cases, pipelined broadcasting allowed and pipelined broadcasting not allowed, are considered. We show that the proposed implementation achieves the linear speedup asymptotically for both cases. Also, under the given mapping method, we discuss how to partition data so as to minimize the total run time and the communication time. We derive sufficient conditions for optimal partitionings. These sufficient conditions are helpful to obtain better partitionings. The optimal partitioning is obtained for a special case.","Title: Probabilistic Coverage Preserving Protocol With Energy Efficiency In Wireless Sensor Networks\nYear: 2007\n\nAbstract: In this paper, we propose a k-coverage preserving protocol to achieve energy efficiency while ensuring the required coverage. In our protocol, we try to select a minimal active set of sensor nodes to reach energy conservation and maintain a complete area k-coverage. We model this problem as a minimum set cover problem and solve it by using a heuristic greedy algorithm. Based on the k-coverage preserving protocol, we then propose a protocol to deal with the probabilistic k-coverage requirement, in which each sensor could be assumed to be able to detect a nearby event with a certain probability. In the probabilistic k-coverage protocol, any point in the monitoring region can be sensed by at least k sensor nodes no lower than a confidence probability. Finally, we evaluate the performance of our protocols with simulations.","Title: Modeling IEEE 802.15.4 based wireless sensor network with packet retry limits\nYear: 2008\n\nAbstract: In this paper, an analytical model for the beacon-enabled slotted CSMA-CA mechanism of IEEE 802.15.4 wireless sensor network is designed. The current mechanism of IEEE 802.15.4 CSMA-CA is extended to include the retransmission limit of the nodes with packet collision probability. A three-dimensional discrete time Markov chain model for the uplink traffic of wireless sensor network is designed to analyze the energy consumption and throughput of the nodes under unsaturated traffic conditions. The energy consumption and throughput are analyzed for different node numbers and data rates to estimate the possible number of nodes for the better performance in terms of throughput.","Title: A Fully Distributed Multi-Channel Mac Protocol For Ad Hoc Networks Based On Location Information\nYear: 2006\n\nAbstract: This paper proposes a distributed multi-channel MAC protocol which is an extension of our early work GRID [1]. GRID is characterized by the following features: (i) it integrates a location-aware channel assignment, (ii) it follows an \"on-demand\" style to access the medium, (iii) the number of channels required is independent of the network topology, and (iv) no form of clock synchronization is required. The proposed protocol wants to further improve the GRID in two parts. First, we propose a fully distributed medium access mechanism without using a single control channel such that all of the network traffic can be distributed evenly over all data channels. Therefore, the network throughput will be increased significantly. Second, we can set the more suitable transmission range and GRID size by considering the factors of host density and packet arrival rate of the network within an specified area. Thus, all of channels will be reused more efficiently than GRID. Simulation results show that the throughput of our protocol is superior to GRID and IEEE 802.11.","Title: Performance Analysis of Multistage Interconnection Networks with Hierarchical Requesting Model\nYear: 1988\n\nAbstract: Analyzes the performance of the multistage interconnection networks (MINs) for interconnecting N processors or N processors to N commonly shared memory modules in a multiprocessor system. A general model, called hierarchical requesting model, has been proposed. The performance of the MINs with respect to their memory bandwidth is analyzed and is compared to that of a crossbar under the proposed model. Based on the analytical results, the authors present a task allocation strategy to increase the memory bandwidth of the MINs.","Title: Hole detection and boundary recognition in wireless sensor networks\nYear: 2009\n\nAbstract: Coverage holes may exist in wireless sensor networks (WSNs) due to presence of obstacles or invalid sensor nodes in the sensing field. Normally, the holes make the data routing failure when the nodes transmit their data back to the sink. In this paper, distributed protocols are developed to identify the boundary nodes surrounding the holes of the sensing filed in WSNs without using any location information. Experimental results demonstrate that our algorithm can precisely and correctly identify the boundary nodes even in sparsely sensors deployed regions. Besides, our algorithm can give better performance in terms of control packet overhead and simulation time as compared to previous work.","Title: A Distributed Location Estimating Algorithm for Wireless Sensor Networks\nYear: 2006\n\nAbstract: The location estimation is a fundamental and essential issue for wireless sensor networks(WSNs). In this paper, we assume that only a few sensor nodes (named as beacon nodes) get their locations by Global Positioning System (GPS) and the remaining nodes without GPS (named as normal nodes) need to estimate their own locations by gathering the nearby neighboring information. Existing works are either too costly or not accurate enough. To improve previous works, we propose a distributed location estimation algorithm for WSNs. In our algorithm, each node without location information only needs to collect the location information of neighboring nodes and use simple computation to estimate its location. Besides, we improve the accuracy of the normal node's estimative region by discarding the communication area of the beacon node (named as the farther neighboring beacon node), which does not cover the normal node, from the original estimative region. We derive some rules to adjust the estimative region according to the relative location of the normal node and the farther neighboring beacon node. Simulation results show that the proposed algorithm achieves better accuracy of estimative locations.","Title: Limited mobility coverage and connectivity maintenance protocols for wireless sensor networks\nYear: 2011\n\nAbstract: Coverage and connectivity maintenance is an important research issue in wireless sensor networks, as sensors are deployed randomly over the monitoring region in large numbers. In the post deployment scenario, existing coverage or connectivity of the network is disturbed due to predictable or unpredictable death of the nodes and maintenance of the network manually is difficult due to physical condition of the monitoring region. In this paper, potential connectivity and coverage maintenance algorithms for the wireless sensor networks are proposed that let the sensors work alternatively by identifying the redundant sensing regions in the post deployed scenarios and maintain the network with limited mobility. Decision of mobility of the nodes among immediate neighbors of a dead node is totally autonomous and distributed, and it is made to maintain the network without disturbing the existing coverage and connectivity. Performance evaluation of our protocols shows that the average mobility distance and energy consumption of the nodes are limited to maintain the coverage and connectivity. Moreover, the proposed algorithms could be worked for the communication range (R\"c) of a node is equal to sensing range (R\"s) or for R\"c","Title: Efficient broadcast in heterogeneous networks of workstations using two sub-networks\nYear: 2005\n\nAbstract: This paper presents efficient algorithms for broadcasting on heterogeneous switch-based networks of workstations (HNOW) by two partitioned sub-networks. In an HNOW, many multiple speed types of workstations have different send and receive overheads. Previous research has found that routing by two sub-networks in a NOW can significantly increase system's performance (Proc. 10th International Conference on Computer Communications and Networks, pp. 68-73, 2001). Similarly, EBS and VBBS (Proc. 8th IEEE International Symposium on Computer and Communication, pp. 1277-1284, (2003)), designed by applying the concept of fastest nodes first, can be executed in O(nlog(n)) time, where n is the number of workstations. This paper proposes two schemes TWO-EBS and TWO-VBBS for broadcasting in an HNOW. These two schemes divide an HNOW into two sub-networks that are routed concurrently and combine EBS and VBBS to broadcast in an HNOW. Based on simulation results, TWO-VBBS outperforms EBS, VBBS, VBBSWF (Proc. 8th IEEE International Symposium on Computer and Communication, pp. 1277-1284, (2003)), the postorder recursive doubling (Proc. Merged IPPS/SPDP Conference, pp. 358-364, (1998)), and the optimal scheduling tree (Proc. Parallel and Distributed Processing Symposium, Proc. 15th International (2001)) generated by dynamic programming in an HNOW.","Title: Initialization protocols for IEEE 802.11-based ad hoc networks\nYear: 2002\n\nAbstract: Leader election and initialization are two fundamental problems in mobile ad hoc networks (MANETs). The leader can serve as a coordinator in the MANETs and the initialization protocol can assign each host a unique and short id. We know that none of the research on initialization for IEEE 802.11-based MANETs has been done. Here, we propose two contention-based leader election and initialization protocols for IEEE 802.11-based single-hop MANETs. Simulation results show that our protocols are efficient.","Title: Typhoon: Resource Sharing Protocol for Metropolitan Vehicular Ad Hoc Networks.\nYear: 2010\n\nAbstract: In this paper, we propose a realistic resource sharing protocol for VANET. The main idea of our protocol comes from typhoons. Typhoons move according to their eyes' mobility, i.e., quorums which are responsible for a given resource holder/requester \"moves\" according to the resource holder's/requester's mobility. Our protocol exploits spatial locality between requesters and resource holders. When resource requesters get their desired resources, they are able to be new resource holders. For hot-resources, requesters are so numerous that the spatial locality is much enhanced over time. Besides, lots of applications (e.g., available parking slot information) in VANET are location-aware which have spatial locality between requesters and resource holders. By the aid of the spatial locality, resource holders/requesters share/query sources in their vicinity in our protocol. Simulation results show that our protocol has lower search latency and well scalability comparing to the previous work. Besides, due to that the spatial locality is enhanced over time, successful rate increases over time.","Title: Performance analysis of multiple bus interconnection networks with hierarchical requesting model\nYear: 1991\n\nAbstract: The authors study the performance of multiprocessor systems employing multiple buses as the interconnection networks under a nonuniform requesting model, called the hierarchical requesting model. The effective memory bandwidth is chosen as the performance measure. The networks investigated include multiple bus networks with full bus-memory connection, multiple bus networks with single bus-memory connection, and multiple bus networks with partial bus-memory connection. The authors also propose a type of multiple bus network with partial bus-memory connection, called partial bus networks with K classes. The N costs and fault-tolerant capabilities of the multiple bus networks are also evaluated and compared to one another. It is shown that the partial bus networks with K classes are useful in applications requiring high performance and degree of fault tolerance with moderate cost","Title: A frequency-aware data-centric mechanism for wireless sensor networks\nYear: 2010\n\nAbstract: Wireless sensor networks (WSNs) are characterized by their low bandwidth, limited energy, and largely distributed deployment. To reduce the flooding overhead raised by transmitting query and data information, several data-centric storage (DCS) mechanisms are proposed. However, the locations of these data-centric nodes significantly impact the power consumption and efficiency for information queries and storage capabilities, especially in a multi-sink environment. This paper proposes a novel dissemination approach, which is namely the dynamic data-centric routing and storage mechanism (DDCRS), to dynamically determine locations of data-centric nodes according to sink nodes' location and data collecting rate and automatically construct shared paths from data-centric nodes to multiple sinks. To save the power consumption, the data-centric node is changed when new sink nodes participate when the WSNs or some queries change their frequencies. The simulation results reveal that the proposed protocol outperforms existing protocols in terms of power conservation and power balancing. Copyright © 2009 John Wiley & Sons, Ltd. The proposed dynamic data-centric routing and storage mechanism (DDCRS) considers multiple sinks with different query frequencies. DDCRS dynamically changes the locations of data-centric nodes and constructs shared paths from data-centric node to multiple sinks for energy conservation.","Title: The broadcast storm problem in a mobile ad hoc network\nYear: 1999\n\nAbstract: Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in par- ticular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broad- casting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we refer as the broadcast storm problem. In this paper, we iden- tify this problem by showing how serious it is through anal- yses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroad- casts to alleviate this problem. Simulation results are pre- sented, which show different levels of improvement over the basic flooding approach.","Title: The broadcast storm problem in a mobile ad hoc network\nYear: 2002\n\nAbstract: Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in particular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broadcasting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we call the broadcast storm problem. In this paper, we identify this problem by showing how serious it is through analyses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcasts to alleviate this problem. Simulation results are presented, which show different levels of improvement over the basic flooding approach.","Title: An optimal broadcasting algorithm without message redundancy in star graphs\nYear: 1995\n\nAbstract: Based on the V.E. Mendia and D. Sarkar's algorithm (1992), we propose an optimal and nonredundant distributed broadcasting algorithm in star graphs. For an n-dimensional star graph, our algorithm takes O(n log2 n) time and guarantees that all nodes in the star graph receive the message exactly once. Moreover, broadcasting m packets in a pipeline fashion takes O(m log2 n+n log2 n) time due to the nonredundant property of our broadcasting algorithm","Title: Target tracking and boundary node selection algorithms of wireless sensor networks for internet services\nYear: 2013\n\nAbstract: Wireless sensor network (WSN) is an integral part of Internet of Things (IoT), in which sensors can be used to keep track with interesting targets under surveillance. Target tracking is one of the important research issues, where sensors are deployed in many applications such as campus security, surveillance, habitat and battle field monitoring. Information can be forwarded in an ad hoc multi-hop fashion via internet to monitor a specific region and can form a ubiquitous network for several internet services. In this paper, Sequential Boundary Node Selection (SBNS) and Distributed Boundary Node Selection (DBNS) algorithms are proposed to find out the boundary nodes of the wireless sensor network. Besides, a target tracking protocol is proposed to detect the entry and exit of the targets using those boundary nodes. Simulation results show that the selection of boundary nodes in our protocol is almost close to the optimal one and the time of selecting boundary nodes would not increase rapidly, with increase in the size of the deployed nodes.","Title: Design and implementation of a distributed file system\nYear: 1991\n\nAbstract: SUMMARY We introduce a new model for replication in distributed systems. The primary motivation for replication lies in fault tolerance. Although there are different kinds of replication approaches, our model combines the advantages of modular redundancy and primary-stand-by approaches to give more flexibility with respect to system configuration. To implement such a model, we select the IBM PC-net with MS-DOS environment as our base. Transparency as well as fault-tolerance file access are the highlights of our system design. To fulfil these requirements, we incorporate the idea of directory-oriented replication and extended prefix tab/es in the system design. The implementation consists of a command shell, a DOS manager, and a recovery manager. Through this design, we can simulate a UNIX-like distributed file system whose function is compatible with MS-DOS.","Title: Design and implementation of a smart mobile robot\nYear: 2005\n\nAbstract: Most wireless sensor networks consist of a large number of static, low-power, short-lived, and unreliable sensors. In this paper, we considered sensor networks consisting of both static and mobile nodes. Integrating both types of devices enables new applications, such as nodes replacement, hole and partition recovery, and autonomous deployment and redeployment. We designed a smart mobile robot and implemented an application of nodes replacement to demonstrate its use, via our nodes replacement algorithm. In this algorithm, the mobile robots can navigate towards low-energy sensor nodes and replace them automatically, with new sensor nodes, having no location information. The navigation algorithm is based on received signal strength between the mobile robot and the communicating node. The experimental results confirm that the mobile robots successfully achieved their assigned tasks.","Title: A group-based multi-channel MAC protocol for wireless ad hoc networks\nYear: 2007\n\nAbstract: When we exploit multiple channels in MAC protocol, we can achieve a higher network throughput than using one single channel due to that multiple transmissions can take place simultaneously. In this paper, we proposed a novel group-based multichannel MAC protocol which cannot only utilize multiple channels to transmit data packets but allow using multiple channels to propagate control packets. The protocol we presented is simple and suitable for wireless ad hoc networks with multiple available channels. The simulation results show that our protocol has the superior performances in network throughput to previous work.","Title: Partitioning and Mapping Nested Loops on Multiprocessor Systems\nYear: 1991\n\nAbstract: A method for executing nested loops with constant loop-carried dependencies in parallelon message-passing multiprocessor systems to reduce communication overhead is presented. In the partitioning phase, the nested loop is divided into blocks that reduce the interblock communication, without regard to the machine topology. The execution ordering of the iterations is defined by a given time function based on L. Lamport's (1974) hyperplane method. The iterations are then partitioned into blocks so that the execution ordering is not disturbed, and the amount of interblock communication is minimized. In the mapping phase, the partitioned blocks are mapped onto a fixed-size multiprocessor system in such a manner that the blocks that have to exchange data frequently are allocated to the same processor or neighboring processors. A heuristic mapping algorithm for hypercube machines is proposed.","Title: Decentralized token-CSMA/CD protocol for integrated voice/data LANs\nYear: 1991\n\nAbstract: In this paper we propose a decentralized protocol for integrated voice and data local area networks. This protocol is based on a hybrid token-CSMA/CD protocol which combines all the merits of the CSMA/CD network and the token-passing network. We apply the hybrid protocol to voice and data individually, and offer two implicit tokens, one voice token and one data token, to achieve the priorities requirements. The voice transmission follows the token-passing protocol with a contention-resolution mechanism. It enforces a bounded delay to guarantee the real-time delivery for voice. This hybrid protocol will serve data of the low priority as fairly as best. To evaluate the protocol's performance, analytical formulations are derived. Numerical results are obtained for the throughput as well as the mean packet delay.","Title: Interest-Based Lookup Protocols for Mobile Ad Hoc Networks\nYear: 2005\n\nAbstract: In this paper, we propose two interest-basedbandwidth-efficient lookup protocols, simple lookup protocol and advanced lookup protocol, for mobile environments. A peer willing to search files broadcasts a query message with keywords relevant to its interests to its neighbors in the transmission range, and only those neighbors also interested in the query forward. Simulation results show that our protocols have higher success rate and raise the scalability and bandwidth efficiency comparing to the previous work. Besides, our protocols can avoid selfish behaviors, since the behavior of forwarding queries benefits not only the source node but also the forwarding node.","Title: Cooperative routing protocol in cognitive radio ad-hoc networks\nYear: 2012\n\nAbstract: Cognitive radio (CR) technology enables the opportunistic use of the vacant licensed frequency bands, thereby improving the spectrum utilization. Therefore, considering end-to-end throughput in CR ad-hoc networks is an important research issue because the availability of local spectrum resources may change frequently with the time and locations. In this paper, we propose a cooperative routing protocol in CR ad-hoc networks. An on-demand routing protocol is used to find an end-to-end minimum cost path between a pair of source and destination. The simulation results show that our proposed cooperative routing protocol not only obtains higher end-to-end throughput, but also reduces the end-to-end delay and the amount of control messages compared to previous work.","Title: Adaptive k-coverage contour evaluation and deployment in wireless sensor networks\nYear: 2013\n\nAbstract: The problem of coverage is a fundamental issue in wireless sensor networks. In this article, we consider two subproblems: k-coverage contour evaluation and k-coverage rate deployment. The former aims to evaluate, up to k, the coverage level of any location inside a monitored area, while the latter aims to determine the locations of a given set of sensors to guarantee the maximum increment of k-coverage rate when they are deployed into the area. For the k-coverage contour evaluation problem, a nonuniform-grid-based approach is proposed. We prove that the computation cost of our approach is at most the square root of existing solutions. Based on our k-coverage contour evaluation scheme, a greedy k-coverage rate deployment scheme (k-CRD) is proposed, which is shown to be an order faster than existing studies for k-coverage rate deployment. The k-CRD can incorporate two different heuristics to further reduce its running time. Simulation results show that k-CRD with these heuristics can be significantly more time efficient without causing much degradation in the coverage rate of final deployment.","Title: An efficient MAC protocol with cooperative retransmission in mobile ad hoc networks\nYear: 2012\n\nAbstract: In emerging wireless networks, cooperative retransmission is employed to replace packet retransmission between a pair of sender and receiver with poor channel condition. A cooperative MAC protocol which utilizes such benefit is proposed in this paper to improve the network performance in mobile ad hoc networks. In the proposed protocol, relay nodes between sender and receiver are used if the sender cannot communicate with the receiver reliably. Furthermore, the receiver may also stop forwarding the received data frame if the frame is received by the next-hop receiver on the route to the final destination node. Simulation results show that the proposed protocol outperforms previous works in terms of increased transmission reliability and reduced delay time. Copyright © 2010 John Wiley & Sons, Ltd.","Title: An Adaptive Quorum-Based Energy Conserving Protocol for IEEE 802.11 Ad Hoc Networks\nYear: 2006\n\nAbstract: The lifetime of a mobile ad hoc network (MANET) depends on the durability of the mobile hosts' battery resources. In the IEEE 802.11 Power Saving Mode, a host must wake up at every beacon interval, to check if it should remain awake. Such a scheme fails to adjust a host's sleep duration according to its traffic, thereby reducing its power efficiency. This paper presents new MAC protocols for power saving in a single hop MANET. The essence of these protocols is a quorum-based sleep/wake-up mechanism, which conserves energy by allowing the host to sleep for more than one beacon interval, if few transmissions are involved. The proposed protocols are simple and energy-efficiency. Simulation results showed that our protocols conserved more energy and extended the lifetime of a MANET.","Title: An efficient reliable broadcasting protocol for wireless mobile ad hoc networks\nYear: 2007\n\nAbstract: The mobile ad hoc network (MANET) has recently been recognized as an attractive network architecture for wireless communication. Reliable broadcast is an important operation in MANET (e.g., giving orders, searching routes, and notifying important signals). However, using a naive flooding to achieve reliable broadcasting may be very costly, causing a lot of contention, collision, and congestion, to which we refer as the broadcast storm problem. This paper proposes an efficient reliable broadcasting protocol by taking care of the potential broadcast storm problem that could occur in the medium-access level. Existing protocols are either unreliable, or reliable but based on a too costly approach. Our protocol differs from existing protocols by adopting a low-cost broadcast, which does not guarantee reliability, as a basic operation. The reliability is ensured by additional acknowledgement and handshaking. Simulation results do justify the efficiency of the proposed protocol.","Title: A distributed Wireless Sensor Network testbed with energy consumption estimation\nYear: 2010\n\nAbstract: In this paper, we design and implement a WSN testbed with a distributed architecture. It allows researchers to submit their experiments and to retrieve the results from the central server. In the testbed, we also propose a software-based hardware-supported scheme to measure the energy consumption of running sensor nodes. And we compare our energy-consumption estimation with oscilloscope measurements. The results show that the energy consumption is very close to oscilloscope measurements.","Title: A Multi-Path QoS Routing Protocol in a Wireless Mobile Ad Hoc Network\nYear: 2001\n\nAbstract: mobile ad hoc network (MANET) is one composed of a set of mobile hosts capable of communicating with each other without the assistance of base stations. This paper considers the QoS (quality-of-service) routing problem in a MANET, which is important for many real-time multimedia applications. We propose an on-demand protocol for searching for a multi-path QoS route from a source host to a destination host in a MANET, where a multi-path is a network with a source and a sink satisfying certain bandwidth requirement. Existing works all try to find a uni-path to the destination. The basic idea is to distribute a number of tickets from the source, which can be further partitioned into subtickets to search for a satisfactory multi-path. Through simulations, we justify that the value of our multi-path protocol is in its flexibility: (i) when the network bandwidth is very limited, it can offer a higher success rate to find a satisfactory QoS route than those protocols which try to find a uni-path, and (ii) when the network bandwidth is sufficient, it can perform almost the same as those protocols which try to find a uni-path (in both routing overhead and success rate).","Title: Circuit-Switched Broadcasting in Multi-Port Multi-Dimensional Torus Networks\nYear: 1999\n\nAbstract: The one-to-all broadcast is the most primary collective communication pattern in a multicomputer network. This paper studies this problem in a circuit-switched torus with α-port capability, where a node can simultaneously send and receive α messages at one time. This is a generalization of the one-port and all-port models. We show how to efficiently perform broadcast in tori of any dimension, any size, square or nonsquare, using near optimal numbers of steps. The main techniques used are: (i) a “span-by-dimension” approach, which makes our solution scalable to torus dimensions, and (ii) a “squeeze-then-expand” approach, which makes possible solving the difficult cases where tori are non-square. Existing results, as compared to ours, can only solve very restricted sizes or dimensions of tori, or use more numbers of steps.","Title: Graph search algorithms and maximum bipartite matching algorithm on the hypercube network model\nYear: 1990\n\nAbstract: In this paper, we propose parallel algorithms for breadth-first search and depth-first search on the hypercube network model. In addition, a parallel algorithm based on the same model for finding maximum matching in bipartite graphs is proposed.","Title: Logical Coordinate Assignment For Geographic Routing In Wireless Sensor Networks\nYear: 2008\n\nAbstract: Purpose - The purpose of this paper is to propose a distributed protocol to build a logical coordinate system based on the hop counts of each node to four selected landmarks, and the real location information is not needed.Design/methodology/approach - The designed protocol uses the sink node as one of the landmarks and then selects three other sensor nodes near the corners of the sensor network as landmarks.Findings - The simulation results show that the proposed protocol has the superior performance in packet delivery ratio, average hop counts among nodes, and communication overhead to previous works.Originality/value - This paper presents a distributed protocol to build a logical coordinate system based on hop counts to landmarks.","Title: Toward optimal broadcast in a star graph using multiple spanning trees\nYear: 1997\n\nAbstract: In a multicomputer network, sending a packet typically incurs two costs: start-up time and transmission time. This work is motivated by the observation that most broadcast algorithms in the literature for the star graph networks only try to minimize one of the costs. Thus, many algorithms, though claimed to be optimal, are only so when one of the costs is negligible. In this paper, we try to optimize both costs simultaneously for four types of broadcast problems: one-to-all or all-to-all broadcasting in an n-star network with either one-port or all-port communication capability. As opposed to earlier solutions, the main technique used in this paper is to construct from a source node multiple spanning trees, along each of which one partition of the broadcast message is transmitted.","Title: A load awareness medium access control protocol for wireless ad hoc network\nYear: 2003\n\nAbstract: A contention-based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA/CA), has the excellence of simple and efficient when the system is light-loaded. The main drawback of such protocols is their inefficiency and unbounded delay when system load is heavy. On the other hand, a contention-free MAC protocol, such as token passing, has better and fair throughput when the system is heavy-loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness wireless ad hoc MAC protocol (which is called the LA protocol) that exploits the benefits of both contention-based and contention-free protocols. A contention-based MAC protocol is used when system is light-loaded and a contention-free one is used otherwise. Our LA protocol, which operates distributed and is fully compatible with IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention-based protocol and the contention-free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols and performs well in all systems loads.","Title: Intelligent medium access for mobile ad hoc networks with busy tones and power control\nYear: 1999\n\nAbstract: In mobile ad hoc networks (MANETs), one essential issue is how to increase channel utilization while avoiding the hidden-terminal and the exposed-terminal problems. Several MAC protocols, such as RTS/CTS-based and busy-tone-based schemes, have been proposed to alleviate these problems. In this paper, we explore the possibility of combining the concept of power control with the RTS/CTS-based and busy-tone-based protocols to further increase channel utilization. A sender will use an appropriate power level to transmit its packets so as to increase the possibility of channel reuse. The possibility of using discrete, instead of continuous, power levels is also discussed. Through analyses and simulations, we demonstrate the advantage of our new MAC protocol. This, together with the extra benefits such as saving battery energy and reducing cochannel interference, does show a promising direction to enhance the performance of MANETs.","Title: A clock synchronization algorithm for multi-hop wireless ad hoc networks\nYear: 2004\n\nAbstract: In multihop wireless ad hoc networks, it is important that all mobile hosts are synchronized. Synchronization is necessary for power management and for frequency hopping spread spectrum (FHSS) operations. IEEE 802.11 standards specify a clock synchronization protocol but this protocol suffers from the scalability problem due to its inefficiency contention mechanism. We propose an automatic self-time-correcting procedure (ASP) to achieve clock synchronization in a multihop environment. Our ASP has two features. Firstly, a faster host has higher priority to send its timing information out than a slower one. Secondly, after collecting enough timing information, a slower host can synchronize to the faster one by self-correcting its timer periodically (which makes it becoming a faster host). Simulation results show that our ASP decreases 60% the average maximum clock drift as compared to the IEEE 802.11 and reduces 99% the number of asynchronism in a large-scale multihop wireless ad hoc networks.","Title: A Distributed Localization Scheme for Wireless Sensor Networks with Improved Grid-Scan and Vector-Based Refinement\nYear: 2008\n\nAbstract: Localization is a fundamental and essential issue for wireless sensor networks (WSNs). Existing localization algorithms can be categorized as either range-based or range-free schemes. Range-based schemes are not suitable for WSNs because of their irregularity of radio propagation and their cost of additional devices. In contrast, range-free schemes do not need to use received signal strength to estimate distances and only need simple and cheap hardware, and are thus more suitable for WSNs. However, existing range-free schemes are too costly and not accurate enough or are not scalable. To improve previous work, we present a fully distributed range-free localization scheme for WSNs. We assume that only a few sensor nodes, called anchors, know their locations, and the remaining (normal) nodes need to estimate their own locations by gathering nearby neighboring information. We propose an improved grid-scan algorithm to find the estimated locations of the normal nodes. Furthermore, we derive a vector-based refinement scheme to improve the accuracy of the estimated locations. Analysis, simulation, and experiment results show that our scheme outperforms the other range-free schemes even when the communication radius is irregular.","Title: An approximation downlink bandwidth allocation scheme for IEEE 802.16 OFDMA system\nYear: 2013\n\nAbstract: Recently, Orthogonal Frequency Division Multiple Access (OFDMA) transmission technique is applied widely in wireless networks because of its high transmission capacity. The IEEE 802.16 standard has also adopted the OFDMA as its access technique. However, the problem of bandwidth resource allocation in time and frequency is essential for efficient utilization of OFDMA system. In this paper, we proposed an approximation resource allocation scheme to improve the downlink bandwidth utilization. In the resource allocation scheme, we sort the requests of users and allocate bandwidth based on dynamic programming strategy which can save the calculation result of subproblems to reduce the executive time of algorithm. In simulations, it is shown that our scheme outperforms the greedy algorithm in bandwidth utilization. Also, we compare our scheme with optimal allocation method, which is implemented by brute force with branch and bound algorithm. The results show that our method outperforms optimal allocation method by bandwidth utilization, stability, and execution time.","Title: Fault-Tolerant Ring Embedding in a Star Graph with Both Link and Node Failures\nYear: 1997\n\nAbstract: The star graph interconnection network has been recognized as an attractive alternative to the hypercube network. Previously, the star graph has been shown to contain a Hamiltonian cycle. In this paper, we consider an injured star graph with some faulty links and nodes. We show that even with fe驴n驴 3 faulty links, a Hamiltonian cycle still can be found in an n-star, and that with fv驴n驴 3 faulty nodes, a ring containing at most 4fv nodes less than that in a Hamiltonian cycle can be found (i.e., the ring contains at least n! 驴 4fv nodes). In general, in an n-star with fe faulty links and fv faulty nodes, where fe + fv驴n驴 3, our embedding is able to establish a ring containing at least n! 驴 4fv nodes.","Title: A Distributed Taxi Hailing Protocol in Vehicular Ad-Hoc Networks\nYear: 2010\n\nAbstract: In this paper, a distributed taxi hailing protocol in vehicular ad-hoc networks (VANET) is suggested. Our protocol consists of two parts: taxi booking and taxi de- blocking. Taxi booking part ensures that a vacant taxi with shortest driving distance to passenger under real traffic regulations is booked. Taxi de-blocking part aims to de-block blocked vacant taxis as soon as possible. Simulation results show that compared with previous results, at least 40% of booking time, 50% of waiting time of passengers and 50% of driving distance from booked taxi to passenger, is reduced in our protocol.","Title: An Energy Conservation MAC Protocol in Wireless Sensor Networks\nYear: 2009\n\nAbstract: Wireless sensor networks use battery-operated computing and sensing devices. Because of the limitation of battery power in the sensor nodes, energy conservation is a crucial issue in wireless sensor networks. Consequently, there is much literature presenting energy-efficient MAC protocols based on active/sleep duty cycle mechanisms to conserve energy. Convergecast is a common communication pattern across many sensor network applications featuring data gathering from many different source nodes to a single sink node. This leads to high data collision rates, high energy consumption, and low throughput near the sink node. This paper proposes an efficient slot reservation MAC protocol to reduce energy consumption and to make transmission more efficient in data gathering wireless sensor networks. The simulation results show that our protocol provides high throughput, low delivery latency and low energy consumption compared to other methods.","Title: Energy-conserving grid routing protocol in mobile ad hoc networks\nYear: 2003\n\nAbstract: The lifetime of a mobile ad hoc network (MANET) depends on the durability of the battery resources of the mobile hosts. Earlier research has proposed several routing protocols specifically for MANET, but most studies have not focused on the limitations of battery resources. The failure of battery resources severely impacts a communications system during natural disasters and in crucial communications environments, such as a battlefield. This study proposes a new energy-aware routing protocol that can increase the durability of the energy resource and, therefore, the lifetime of the mobile hosts and the MANET. The proposed protocol can conserve energy by shortening the idle period of the mobile hosts without increasing the probability of packet loss or reducing routing fidelity. Simulation results indicate that this new energy-conserving protocol can extend the lifetime of a MANET.","Title: Virtual landmarks assisted routing protocol in Vehicular Ad hoc Networks\nYear: 2009\n\nAbstract: How to route packets efficiently and reliably is an important issue in Vehicular Ad hoc Networks (VANETs). Due to the high mobility of vehicles, the communication topology of vehicles in VANET changes rapidly. In this paper, a Virtual Landmarks-based approach is suggested. Under the assistant of Virtual Landmarks, an efficient path is guaranteed even if the roads topology is complex. Our approach is applicable to routing packets between a vehicle and static destination. Simulation results shows that in comparison with previous work, our approach has much lowest communication cost and guarantees a reliable path.","Title: BlueCube: constructing a hypercube parallel computing and communication environment over Bluetooth radio system\nYear: 2003\n\nAbstract: In existing parallel computing structures, hypercubes have several distinct advantages; they support parallel computing, provide disjoint path and tolerate faults. If devices with computing capabilities can be linked as a hypercube by taking advantage of Bluetooth radio's features, then a high performance computing and efficient communication environment can be established by applying currently used algorithms. This is a pilot study of applying Bluetooth wireless technology to construct a parallel computation and communication environment. A three-stage distributed construction protocol is presented for automatically constructing a hypercube computing environment from Bluetooth devices. The proposed protocol tackles the link construction, role assignment, scatternet formation and network management problems, to construct efficiently a hypercube structure. The proposed protocol enables Bluetooth devices easily to construct a routing path, tolerate faults and create disjoint paths. Parallel and distributed computing will be realized in a Bluetooth wireless environment. Experimental results show the proposed protocol will be able to set up a scatternet that is appropriate for parallel computing and communications","Title: A Traffic-Aware Scheduling for Bluetooth Scatternets\nYear: 2006\n\nAbstract: Bluetooth is a low cost, low power, short-range radio technology used for wireless personal area networks (PANs). Bluetooth scatternet is a set of piconets interconnected via bridge devices. Good interpiconet schedulings are necessary for bridge devices to switch among piconets they participate in. This paper proposes an interpiconet scheduling algorithm named \"Traffic-Aware Scatternet Scheduling” (TASS), for bridges in Bluetooth scatternets. According to masters' traffic information, TASS can adaptively switch the bridge to high traffic load masters, and increase the usage of the bridge. In addition, TASS can reduce the number of failed \"unsniffs” and the overhead of \"bridge switch wastes” to further increase overall system performance. Simulation results show that TASS outperforms existing interpiconet scheduling in both network throughput and adaptability for various traffic loads.","Title: A cooperative MAC protocol based on 802.11 in wireless Ad hoc networks\nYear: 2013\n\nAbstract: Cooperative communications among nodes is an efficient method to decrease signal fading and interference in MAC layer of wireless Ad hoc networks. However, the previous cooperative MAC protocols are designed for IEEE 802.11b, but not for later standard IEEE 802.11g or 802.11n. To increase performance, improve reliability and reduce energy consumption in communications, we propose a cooperative MAC protocol for IEEE 802.11g and being extended to 802.11n. By partitioning the relays with similar transmission rates into same groups, we can reduce efficiently the time for selecting better relays to help data transmission. Furthermore, we propose a novel retransmission scheme to reduce the retransmission time, while once data transmission is fail, only the relays which have received the data frame will help for retransmission instead of repeating all retransmission cycle. Simulation results show that our proposed protocol outperforms previous work by increasing the throughput and reducing the average delay time in transmission.","Title: Tolerating faults in injured hypercubes using maximal fault-free subcube-ring\nYear: 1997\n\nAbstract: In this paper, we present a reconfiguration approach to identify the maximal fault-free subcube-ring for tolerating faults in injured hypercubes. The fault-free subcube-ring is connected by a ring of fault-free subcubes with dilation 3. By exploiting the size of fault-free subcubes as large as possible, the maximal fault-free subcube-ring with higher processor utilization is obtained. Using this approach, we can tolerate more than n faults in n -dimensional hypercubes. To demonstrate the fault-tolerant capability of our approach, we implement two fault-tolerant algorithms, matrix-multiplication and sorting algorithms, on the n CUBE/2E hypercube machine with 32 processors. The simulation results show that our reconfiguration approach has low performance slowdown and high processor utilization.","Title: Bubblesort star graphs: a new interconnection network\nYear: 1996\n\nAbstract: In this paper, we propose and analyze a new interconnection network called bubblesort star graph, which is the merger of the bubblesort graph and the star graph. We present the deadlock-free wormhole routing algorithm for the proposed network. We also develop the method to embed a mesh into a bubblesort star graph with dilation two and expansion one. Besides, we use the recursive scheme to embed the multiple disjoint copies of the hypercube into a bubblesort star graph with all faults recovery capacity as well as constant expansion and dilation one or two. This reflects the fact that the embeddability of the bubblesort star graph is much better than that of the star graph.","Title: Dynamic channel allocation with location awareness for multi-hop mobile ad hoc networks\nYear: 2002\n\nAbstract: The wireless mobile ad hoc network (MANET) has received a lot of attention recently. This paper considers the channel assignment problem in a MANET which has access to multiple channels. Although a MANET does not have the infrastructure of base stations, interestingly its channel assignment can be conducted efficiently in a way very similar to that in cellular systems (such as GSM). In this paper, we propose a new location-aware channel assignment protocol called GRID-B (read as GRID with Channel Borrowing), which is a sequel of our earlier GRID protocol [Location-aware channel assignment for a multi-channel mobile ad hoc network, Technical Report NCU-HSCCL-2000-02, 2000]. The protocol assigns channels to mobile hosts based on the location information of mobile hosts that might be available from the positioning device (such as GPS) attached to each host. According to our knowledge, no location-aware channel assignment protocol has been proposed before for MANETs. Several channel borrowing strategies are proposed to dynamically assign channels to mobile hosts so as to exploit channel reuse and resolve the unbalance of traffic loads among different areas (such as hot and cold spots). We then propose a multi-channel MAC protocol, which integrates GRID-B. Extensive simulation results are presented to show the advantage of the new GRID-B protocol.","Title: An Efficient Transmission Protocol Based on Network Coding in Delay Tolerant Networks\nYear: 2013\n\nAbstract: In Delay Tolerant Networks, the delay of packets is long due to the intermittent connections caused by the mobility of nodes. Epidemic Routing Protocol can reduce the delay time and raise the packet delivery rate by replicating and spread copies of source packets in the networks, but it inevitably exhaust memory resources and network bandwidth. In this paper, we propose a network coding with limited buffer routing protocol. When a buffer of a node is full, two packets in the buffer are chosen randomly and encoded linearly together in to a packet to save buffer space and improve the performance in many-to-one communications.","Title: Novel Channel-Hopping Schemes for Cognitive Radio Networks\nYear: 2014\n\nAbstract: Recently, cognitive radio (CR) has become a key technology for addressing spectrum scarcity. In CR networks, spectrum access should not interfere the colocate incumbent networks. Due to the requirement above, common control channel approaches, which are widely used in traditional multichannel environments, may face serious CR long-time blocking problem and control channel saturation problem. Although channel-hopping-based approaches can avoid these two problems, existing works still have significant drawbacks including long time-to-rendezvous, unbalance channel loading, and low channel utilization. In this paper, we introduce three channel-hopping approaches, RCCH, ARCH, and SARCH for synchronous and asynchronous environments, respectively. Compared with previous works, our schemes outperform the state of the art in terms of these metrics.","Title: Power control based topology construction for the distributed wireless sensor networks\nYear: 2007\n\nAbstract: Wireless sensor network consists of large number of sensor nodes with limited battery power, which are randomly deployed over certain area for several applications. Due to limited energy resource of sensors, each of them should minimize the energy consumption to prolong the network lifetime. In this paper, a distributed algorithm for the multi-hop wireless sensor network is proposed to construct a novel energy efficient tree topology, without having location information of the nodes. Energy conservation of the nodes is accomplished by controlling transmission power of the nodes. Besides, maintenance of the network topology due to energy scarcity of the gateway nodes is also proposed in the protocol. Simulation results show that our distributed protocol can achieve energy conservation up to an optimum level similar to the centralized algorithm that we have considered and can extend the network lifetime as compared to other distributed algorithms without any power control.","Title: Distributed Localization Scheme for Mobile Sensor Networks\nYear: 2010\n\nAbstract: Localization is an essential and important research issue in wireless sensor networks (WSNs). Most localization schemes focus on static sensor networks. However, mobile sensors are required in some applications such that the sensed area can be enlarged. As such, a localization scheme designed for mobile sensor networks is necessary. In this paper, we propose a localization scheme to improve the localization accuracy of previous work. In this proposed scheme, the normal nodes without location information can estimate their own locations by gathering the positions of location-aware nodes (anchor nodes) and the one-hop normal nodes whose locations are estimated from the anchor nodes. In addition, we propose a scheme that predicts the moving direction of sensor nodes to increase localization accuracy. Simulation results show that the localization error in our proposed scheme is lower than the previous schemes in various mobility models and moving speeds.","Title: A Distributed Routing Protocol and Handover Schemes in Hybrid Vehicular Ad Hoc Networks\nYear: 2011\n\nAbstract: Vehicular Ad Hoc Networks (VANETs) have received considerable attention in recent years. VANETs provide many services and applications such as Internet access Voice over Internet Protocol (VoIP) and information dissemination. Due to dynamic changes in the network topologies, various routing protocols have been studied in the vehicular environments. However, the communications between source and destination vehicles involve many intermediate vehicles, and due to the high mobility of vehicles, these communication links become disconnected. In this paper, we propose a distributed routing protocol in VANETs with the help of roadside units (RSUs). The proposed scheme includes vehicle registration, finding the location of destination vehicle and the handover maintenance. The simulation results show that our proposed protocol is suitable for vehicles communications in VANETs.","Title: A Wireless Human Motion Capturing System for Home Rehabilitation\nYear: 2009\n\nAbstract: Following the trend of miniature intelligent sensing, wearing small, integrated wireless sensor nodes, such as one with accelerometers and compasses, to capture human body motions may have many applications in medical care and computer animation. In this paper, we demonstrate the use of intelligent sensors to capture human motions for home rehabilitation. We design a game to help a patient to conduct his/her rehabilitation program. For each exercise, the patient is instructed to wear sensors on specified movable body parts. The system will then estimate the quality of the movements and give scores as if it is advised by a therapist. In this way, patients will no longer feel painful and boring as that in traditional rehabilitation, which is typically done in hospitals.","Title: Toward Optimal Complete Exchange on Wormhole-Routed Tori\nYear: 1997\n\nAbstract: In this paper, we propose new routing schemes to perform all-to-all personalized communication (or known as complete exchange) in wormhole-routed, one-port tori. On tori of equal size along each dimension, our algorithms use both asymptotically optimal startup and transmission time. The results are characterized by several interesting features: 1) the use of gather-scatter tree to achieve optimality in startup time, 2) enforcement of shortest paths in routing messages to achieve optimality in transmission time, 3) application of network-partitioning techniques to reduce the constant associated with the transmission time, and 4) the dimension-by-dimension and gather-scatter-tree approach to make possible applying the results to nonsquare, any-size tori. In the literature, some algorithms are optimal in only one of startup and transmission costs, while some, although asymptotically optimal in both costs, will incur much larger constants associated with the costs. Numerical analysis and experiment both show that significant improvement can be obtained by our scheme on total communication latency over existing results.","Title: A Fast Video-on-Demand Broadcasting Scheme for Popular Videos\nYear: 2004\n\nAbstract: Abstract—Broadcasting is a prospective approach to support near video-on-demand services with light communication over- head. By letting clients share channels, such approaches involve partitioning a video into segments and repeatedly broadcasting these segments in multiple channels. An early paper proposed a broadcasting scheme called RFS (recursive frequency splitting), which can significantly reduce clients’ waiting time. While efficient, RFS suffers from a high computational complexity of , where is the number of segments of the video, which is typically very large. This paper proposes an efficient segmentation scheme, which can significantly reduce the compu- tational overhead by slightly sacrificing the number of segments that can be arranged as compared to RFS. Index Terms—Broadcasting, broadband networks, cable TV, video-on-demand.","Title: Channel-sharing strategies in two-tier cellular PCS systems\nYear: 2002\n\nAbstract: A two-tier cellular network is characterized by macrocells and microcells overlapping in the service area. This overlapping property provides an advantage that traffic loads can be shared by channels of the two tiers to increase the performance of the system. In this paper, we propose two channel-sharing strategies, namely vertical channel-sharing and vertical-horizontal channel-sharing, to better utilize channels of the network. The call loss probability of new calls and call dropping probability of handoff calls are developed through analyses and simulations. The results justify the advantage of our strategies over existing strategies.","Title: Efficient allocation of chain-like task on chain-like network computers\nYear: 1990\n\nAbstract: In this paper, we propose an algorithm to improve Bokhari's method for allocation of chain-like task on chain-like network computers. The time complexity of our algorithm is reduced from the time complexity O(m3n) of Bokhari's to O(min(m,n)m2), where m is the number of modules and n is the number of processors. In addition, our algorithm relaxes Bokhari's constraints of all processors to be utilized and n < m.","Title: An On-Demand Bandwidth Reservation QoS Routing Protocol for Mobile Ad Hoc Networks\nYear: 2006\n\nAbstract: QoS routing is the key to support multimedia services in mobile ad hoc networks (MANETs). It is known that resource reservation is one of the best technique to guarantee QoS in MANETs. Lots of the reservation-based QoS routing protocols have been proposed before. However, the effective bandwidth calculation problem and the bandwidth reservation problem have not been addressed seriously. Here, we proposed an on-demand bandwidth reservation QoS routing protocol for TDMA-based multihop MANETs. We propose an algorithm to guide the destination to choose the route that is most likely to satisfy the QoS requirement and an algorithm to reserve the proper time slot and thus keeps more free time slots for other requests. Simulation results show that our protocol can achieve high route establishment probability and low packet loss rate","Title: Zooming: A Zoom-Based Approach for Parking Space Availability in VANET\nYear: 2010\n\nAbstract: In this paper, we propose a zoom-based approach for parking space availability. The main idea of our scheme lies on the fact that drivers near the queried locations are interested in detail (zoomed-in) parking space information, while drivers in a distant place are interested in rough (zoomed-out) information about free parking spaces. Our zooming technique is based on discrete cosine transform. Besides, a winner-take-all scheme is also proposed to further reduce communication overhead in packet loss environment. As compared to previous work, simulation results show that our scheme reduces 40% to 50% communication overhead.","Title: Route maintenance in a wireless mobile ad hoc network\nYear: 2000\n\nAbstract: A mobile ad-hoc network (MANET) is formed by a cluster of mobile hosts, each installed with a wireless transceiver, without the assistance of base stations. Due to the transmission range constraint of transceivers, two mobile hosts can communicate with each other either directly, if they are close enough, or indirectly, by having other mobile hosts relay their packets. Several routing protocols, such as DSR, SSA, AODV, and ZRP, have been proposed for a MANET with a dynamically changing topology. In a MANET, a route may suddenly become broken because only one host roams away. Even if a route remains connected, it may become worse due to host mobility or a better route newly being formed in the system. Existing protocols, however, will stick with a fixed route between a source-destination pair once it is discovered, until it expires or is broken. In this paper, we show how to enhance several existing protocols with route optimization and local route recovery capability, such that the routing paths can be adjusted on-the-fly while they are still being used for delivering packets or can be patched in minimum wireless bandwidth and packet transmitting delay while route errors occur.","Title: Efficient path-based multicast in wormhole-routed mesh networks\nYear: 2000\n\nAbstract: The capability of multidestination wormhole allows a message to be propagated along any valid path in a wormhole-routed network conforming to the underlying base routing scheme. The multicast on the path-based routing model is highly dependent on the spatial locality of destinations participating in multicasting. In this paper, we propose two proximity grouping schemes for efficient multicast in wormhole-routed mesh networks with multidestination capability by exploiting the spatial locality of the destination set. The first grouping scheme, graph-based proximity grouping , is proposed to group the destinations together with locality to construct several disjoint sub-meshes. This is achieved by modeling the proximity grouping problem to graph partitioning problem. The second one, pattern-based proximity grouping , is proposed by the pattern classification schemes to achieve the goal of the proximity grouping. By simulation results, we show the routing performance gains over the traditional Hamiltonian-path routing scheme.","Title: Statement-Level Communication-Free Partitioning Techniques for Parallelizing Compilers\nYear: 1996\n\nAbstract: This paper addresses the problem of communication-free partition of iteration spaces and data spaces along hyperplanes. To finding more possible communication-free hyperplane partitions, we treat statements within a loop body as separate schedulable units. Instead of using the information about data dependence distance or direction vectors, our technique explicitly formulates array references as transformations from statement-iteration spaces to data spaces. Based on these transformations, the necessary and sufficient conditions for communication-free partition along hyperplanes to be feasible have been proposed. This approach can be applied to all programs with an imperfectly nested loop or sequences of imperfectly nested loops, whose array references are affine functions of outer loop indices or loop invariant variables. The proposed approach is more practical than existing methods in finding the data and computation distribution patterns that can cause the processor to execute fully-parallel on multicomputers without any interprocessor communication.","Title: A Region-Based Hierarchical Location Service with Road-Adapted Grids for Vehicular Networks\nYear: 2010\n\nAbstract: In VANETs, it is very important to communicate between two vehicles, but how to get the correct position of a vehicle is not easy. Due to vehicles are moving fast, topology in VANETs changes rapidly. As a result, location services processed in VANETs are more difficult than in MANETs. In our thesis, we propose a hierarchical location service system, it provides a low cost and rapid service. First, we select the main arteries to divide network into grids because of there are more vehicles than in normal roads, and then design a mechanism that when vehicles need to send update packets. This mechanism can decrease the number of update packets and still gain correct vehicles‟ location. Second, we design grids with three levels, the higher the level, the larger the area. Each level stores update packets sent within its area. Vehicles using our system can find the destination vehicle distributedly within a small area; if the target is not within this area, then find within a larger area. Besides, we propose a packets collection method, it can be adjusted with different size of collection area. The simulation results show that our scheme could decrease the number of location update packets effectively, and keep high success rate of location service.","Title: A dynamic channel-borrowing approach with fuzzy logic control in distributed cellular networks\nYear: 2004\n\nAbstract: In this paper, a fuzzy-based dynamic channel-borrowing scheme (FDCBS) is presented to maximize the number of served calls in a distributed wireless cellular network. The uneven traffic load may create hot-spot cells and possibly causes a high blocking rate in hot-spot cells. Most conventional methods use load indices with a threshold value to determine the load status of a cell. However, those exists a ping–pong effect, as loads are around the threshold value. This result causes an unstable system and unnecessary message passing overhead. In addition, the estimation of traffic load is difficult and time-consuming. Thus, an intelligent prediction mechanism is needed. In this paper, we develop a method to predict the cell load and to solve the channel-borrowing problem based on the fuzzy logic control. A new channel-borrowing algorithm with multi-channels borrowing is also presented in this paper. A borrowing mechanism supporting the present facility has been built on the application-level of wireless cellular networks. The FDCBS exhibits better adaptability, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. Through simulations, we evaluate the blocking rate, update overhead, and channel acquisition delay time of the proposed method. The results demonstrate that our algorithm has lower blocking rate, less updated overhead, and shorter channel acquisition delays.","Title: Efficient index generation for compiling two-level mappings in data-parallel programs\nYear: 2000\n\nAbstract: This paper presents compilation techniques to compress holes, which are caused by the non-unitalignment stride in a two-level data-processor mapping. Holes are the memory locations mapped byuseless template cells. To fully utilize the memory space, memory holes should be removed. In a twoleveldata-processor mapping, there is a repetitive pattern for array elements mapped onto processors.We classify blocks into classes and use a class table to record the distribution of each class in the...","Title: Design and implementation of a navigation system for autonomous mobile robots\nYear: 2010\n\nAbstract: In this paper, a navigation system for autonomous mobile robots is proposed. Our navigation system is a hybrid of behaviour-based and model-based navigation systems. In our system, a behaviour-based subsystem is in charge of low-level reactive actions, and a model-based subsystem is responsible for high-level planned actions. If there are obstacles in the way, the navigation system will use our obstacle avoidance algorithm to navigate around these obstacles and keep the robot moving towards the destination. On the basis of our experimental results, our navigation system can navigate the robot to the destination effectively.","Title: A mobile scaffolding-aid-based bird-watching learning system\nYear: 2002\n\nAbstract: In this paper, we develop a mobile scaffolding-aid-based bird-watching learning system, which aims to construct an outdoor mobility-learning activity under the up-to-date wireless technology. The proposed bird-watching learning (BWL) system is designed on the wireless mobile ad-hoc network. In the BWL system, each learner device has PDA (personal digital assistances) with a Wi-Fi (IEEE 802.11b) card, within a WLAN environment. Specially, the BWL system contains a mobile learn sheet sub-system, which integrates the scaffolding-aid learn model into the BWL system. Finally, we conduct a formative evaluation to provide statistical results, which is evaluated for the following two purposes; (1) to explore the possible roles and scaffolding aids that the mobile PDA of the BWL system can play and offer in the bird-watching activities, (2) to investigate if the affective and cognitive learning could be possibly benefited from the mobility, portability, and individualization of the mobile PDA of the BWL system.","Title: A Clock Synchronization Algorithm for Multihop Wireless Ad Hoc Networks\nYear: 2007\n\nAbstract: In multihop wireless ad hoc networks, it is important that all mobile hosts are synchronized. Synchronization is necessary for power management and for frequency hopping spread spectrum (FHSS) operations. IEEE 802.11 standards specify a clock synchronization protocol but this protocol suffers from the scalability problem due to its inefficiency contention mechanism. In this paper, we propose an automatic self-time-correcting procedure (ASP) to achieve clock synchronization in a multihop environment. Our ASP has two features. First, a faster host has higher priority to send its timing information out than a slower one. Second, after collecting enough timing information, a slower host can synchronize to the faster one by self-correcting its timer periodically (which makes it becoming a faster host). Simulation results show that our ASP decreases 60% the average maximum clock drift as compared to the IEEE 802.11 and reduces 99% the number of asynchronism in a large-scale multihop wireless ad hoc networks.","Title: A distributed protocol for query execution in sensor networks\nYear: 2005\n\nAbstract: The paper proposes an efficient distributed protocol to find a subset of connected sensor nodes to cover the queried region. Each node determines whether to be a sensing node to sense the queried region according to its priority, which is represented by the remaining power or sensing area within the queried region. The proposed protocol can efficiently construct a subset of connected sensing nodes and respond the query request to the sink node. Simulation results show that the proposed protocol is more efficient and has a lower communication overhead than the existing protocol.","Title: A mobile butterfly-watching learning system for supporting independent learning\nYear: 2004\n\nAbstract: In this paper, we describe the development of a mobile butterfly-watching learning (BWL) system which supports independent learners by offering a new pattern of outdoor mobile learning (or called as m-learning) activities. The proposed BWL system was designed using a wireless mobile ad-hoc learning environment. In our designed system, each individual learner has a wireless handheld device, which is a PDA (personal digital assistant) with an IEEE 802.11 wireless network card and a small-sized CCD camera. One instructor has a notebook computer with a wi-fi wireless LAN card which serves as the local server. The notebook has a complete butterfly database. All learners' wireless handheld devices and the notebook constitute a mobile ad-hoc learning environment. During the butterfly-watching activity, each learner takes a distinct butterfly picture, and wirelessly transmits the picture to the local server. A content-based butterfly-image retrieval technique is applied to search for the most closely matching butterfly information, which is returned in real time to the learner's wireless handheld device. To illustrate the effect of the BWL system, an outdoor BWL activity was actually performed at elementary school in Taiwan. This article reports on our attempts to develop a new m-learning system to support an independent learning model. We deeply believe that it is worth developing a mobile learning system to provide a possible independent-learning environment for outdoor learners.","Title: Efficient address generation for affine subscripts in data-parallel programs\nYear: 1998\n\nAbstract: This paper presents an efficient compilation technique to generate the local memory access sequences for block-cyclically distributed array references with affine subscripts in data-parallel programs. For the memory accesses of an array reference with affine subscript within a two-nested loop, there exist repetitive patterns both at the outer and inner loops. We use tables to record the memory accesses of repetitive patterns. According to these tables, a new start-computation algorithm is proposed to compute the starting elements on a processor for each outer loop iteration. The complexities of the table constructions are O(k+s2), where k is the distribution block size and s2 is the access stride for the inner loop. After tables are constructed, generating each starting element for each outer loop iteration can run in O(1) time. Moreover, we also show that the repetitive iterations for outer loop are Pk/gcd(Pk,s1), where P is the number of processors and s1 is the access stride for the outer loop. Therefore, the total complexity to generate the local memory access sequences for a block-cyclically distributed array with affine subscript in a two-nested loop is O(Pk/gcd/(Pk,s1)+k+s 2)","Title: Power management protocol for regular wireless sensor networks\nYear: 2005\n\nAbstract: Most of the existing power saving protocols are designed for irregular networks. These protocols can also be applied to regular networks, but these protocols do not consider the characteristics of regular networks and thus are more complicated and less efficient than the protocols designed for regular networks. Therefore, we propose a novel power management protocol for regular WSNs. Gathering information to the base station is an important operation for WSN. Hence, even some nodes switch to PS mode, the network still needs to be connected so that the sensed information can be sent to the base station through the active nodes. The goal of our protocols is to choose several different connected dominating sets, so that these connected dominating sets can switch to active mode in turn to serve other nodes in PS mode. Simulation results show that our power management protocol can conserve lots of power and greatly extend the lifetime of the WSN with a reasonable extra transmission delay.","Title: Fault-tolerant ring embedding in star graphs\nYear: 1996\n\nAbstract: We consider an injured star graph with some faulty links and nodes. We show that even with fe⩽n-3 faulty links a Hamiltonian cycle still can be found in an n-star, and that with fv ⩽n-3 faulty nodes a ring containing at most 4fv nodes less than that in a Hamiltonian cycle can be found (i.e., containing at least n!-4fv nodes). In general, in an n-star with fe faulty links and fv faulty nodes, where f e+fv⩽n-3 our embedding is able to establish a ring containing at least n!-4fv nodes","Title: Compiling array references with affine functions for data-rarallel programs\nYear: 1998\n\nAbstract: An important research topic is parallelizing of compilers to generate local memory access sequences and communication sets while compiling a data-parallel language into an SPMD (Single Program Multiple Data) program. In this paper, we present a scheme to efficiently enumerate local memory access sequences and to evaluate communication sets. We use a class table to store information that is extracted from array sections and data distribution patterns. Given array references and data distributions, we can utilize the class table to generate communication sets in closed forms. Furthermore, we derive the algorithms for sending and receiving necessary data between processors. An algorithm for generating the class table is presented, and the time complexity of this algorithm is O(s), where s is the array section stride. The technique of generating communication sets for one index variable has been implemented on a DEC Alpha 3000 workstation. The experimental results confirm the advantage of our scheme, especially when the array section stride is larger than the block size. Finally, we adapt our approach to handle array references with multiple index variables. The time complexity for constructing the whole class table is O(s(2)).","Title: A Comment on \"Short Channel Hopping Sequence Approach to Rendezvous for Cognitive Networks\".\nYear: 2014\n\nAbstract: Recently, Reguera et al. proposed a channel hopping scheme called short-sequence-based (SSB) rendezvous algorithm which works under symmetric and asymmetric channel models. After our revisit of the SSB implementation under the asymmetric model, we found that some cases will fail to have rendezvous in the asynchronous environment and the performance of SSB cannot be guaranteed as one would expect. In addition, we propose a conjecture for the failing cases.","Title: Design and implementation of a transmission protection protocol to improve the performance of wireless sensor networks in hybrid networks\nYear: 2014\n\nAbstract: In hybrid networks, the devices of Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) will interfere with each other when working in a same area because they use the same band, 2.4 GHz. With the greater transmission power and more aggressive channel access time resolution, WLANs often affect the communication of WSNs severely. To eliminate this kind of interference effect, we design protection nodes and propose a transmission protection protocol, WSNs Transmission Protection Protocol (WTPP), to improve the transmission performances of WSNs in hybrid networks. The protection nodes can emit protection signal periodically to block the traffic of WLANs and permit the transmission of WSNs. We implement WTPP in a hybrid network testbed to prove its feasibility. Comparing with legacy ZigBee, the experimental results show that WTPP can improve the packet delivery ratio of WSNs efficiently under the interference of WLANs. When WSNs work on low duty cycle, the throughput degradation of WLANs is less than 6%.","Title: Interference-aware channel allocation algorithm with game theoretic approach for cognitive radio networks\nYear: 2014\n\nAbstract: In cognitive radio networks, the Secondary Users (SUs) are allowed to utilize unused portions of the licensed spectrum to enhance the performance and efficiency of the channel resource in networks. However, with the increasing number of wireless devices and users competence for the limited channel resource, the channel allocation problem has become an important issue in the cognitive radio networks. Moreover, the interference in communication has become an important factor that affects the efficiency of transmission in cognitive radio networks. In this paper, we proposed an algorithm with game theoretic approach to solve the problem of channel allocations in cognitive radio networks, based on interference aware information between communication pairs. By game theory, the channel allocations of SUs are proposed by their perceived utilities associated with possible actions of neighboring users. The effectiveness of the communication links is determined by the bandwidth of the available channels to the SUs and the heterogeneous interference range between the communication links. Our proposed algorithm can achieve Nash Equilibrium convergence in the game theory.","Title: A registration system for aiding in localization and routing in hybrid VANETs\nYear: 2012\n\nAbstract: Hybrid vehicular ad hoc networks (VANETs) allow Inter-Vehicle Communications and Roadside-to-Vehicle Communications. The proposed protocol utilizes the Roadside Units (RSUs) for the implementation of a registration process which allows for the provision of a localization service. The presented RSUs architecture breaks the VANETs into smaller regions managed by a RSU in which individual On Board Units (OBUs) register providing its current position and velocity vectors. Using the data provided by the OBUs, a localization service can be implemented. When the source need to send data, the location of the destination is calculated at the source RSU and the destination RSU using controlled flooding locates the destination vehicle and establishes a route path between source and destination. Simulation results show that it performs well providing good throughput, high packet delivery ration, low delivery delays with very low overhead.","Title: A Hole Avoiding Routing Protocol in Wireless Sensor Networks\nYear: 2014\n\nAbstract: In wireless sensor networks, an important challenge often faced in geographic greedy forwarding is the local minimum phenomenon which is caused by holes. For solving this problem, most hole-avoiding protocols route packets along the perimeter of holes or forbidden regions. Thus, sensor nodes on the perimeter of holes and forbidden regions exhaust their energy faster than others, which enlarge the hole size, called growing hole problem. In this paper, we propose an energy-efficient hole avoiding routing protocol (HARP) for growing hole problem in multi-hole environments.","Title: Designing efficient parallel algorithms on mech-connected computers with multiple broadcasting\nYear: 1990\n\nAbstract: Semigroup and prefix computations on two-dimensional mesh-connected computers with multiple broadcasting (2-MCCMBs) are studied. Previously, only square 2-MCCMBs with N processing elements were considered for semigroup computations of N data items, andO(N/sup 1/6/) time was required. It is found that square machines are not the best form for semigroup computations, and an O(N/sup 1/8/)-time algorithm is derived on an N/sup 5/8/*N/sup 3/8/ rectangular 2-MCCMB. This time complexity can be further reduced toO(N/sup 1/9/) if fewer processing elements are used. Parallel algorithms for prefix computations with the same time complexities are derived.","Title: A new fuzzy linear mapping technique for facial feature extraction and recognition\nYear: 1996\n\nAbstract: Fast feature matching process and high recognition rates are two important issues in face recognition systems. In this paper, a fuzzy neural network based face recognition system which addresses on these two subjects is proposed. This face recognition system uses a fuzzy linear mapping for feature extraction and a fuzzy neural network for fuzzy feature matching. Experimental results show that the proposed face recognition system has two advantages: 1) higher recognition rates are achieved in comparison with statistical feature extraction methods; and 2) feature matching process using fuzzy neural network is faster than minimum distance classifier","Title: Wildcard Rules Caching and Cache Replacement Algorithms in Software-Defined Networking.\nYear: 2016\n\nAbstract: In software-defined networking, flow tables of OpenFlow switches are implemented by ternary content addressable memory (TCAM). Although TCAM can process input packets in high speed, it is a scarce and expensive resource providing only a few thousands of rule entries on a network switch. Rules caching is a technique to solve the TCAM capacity problem. However, the rule dependency problem is a chall...","Title: Asynchronous Quorum-Based Blind Rendezvous Schemes for Cognitive Radio Networks.\nYear: 2016\n\nAbstract: In cognitive radio networks, unlicensed users [secondary users (SU)] need to rendezvous on licensed channels before establishing communication links. Dedicated common control channel is the simplest way to achieve rendezvous. However, due to the absolute priority of licensed users [primary users (PU)] on accessing licensed channels, a dedicated common control channel may cause the PU long-time blo...","Title: A Game Theory Based Congestion Control Protocol for Wireless Personal Area Networks.\nYear: 2016\n\nAbstract: In wireless sensor networks (WSNs), the presence of congestion increases the ratio of packet loss and energy consumption and reduces the network throughput. Particularly, this situation will be more complex in Internet of Things (IoT) environment, which is composed of thousands of heterogeneous nodes. RPL is an IPv6 routing protocol in low power and lossy networks standardized by IETF. However, the RPL can induce problems under network congestion, such as frequently parent changing and throughput degradation. In this paper, we address the congestion problem between parent nodes and child nodes in RPL-enabled networks, which typically consist of low power and resource constraint devices. To mitigate the effect of network congestion, we design a parent-change procedure by game theory strategy, by which the child nodes can change next hop neighbors toward the sink. Comparing to the ContikiRPL implementation, the simulation results show that our protocol can achieve more than two times improvement in throughput and reduce packet loss rate with less increasing of average hop count.","Title: A transmission protocol based on network coding in many-to-one delay tolerant networks\nYear: 2015\n\nAbstract: In delay tolerant networks DTNs, the delay of packets is long due to the intermittent connections caused by the mobility of nodes. Epidemic routing protocol ERP can reduce the delay time and raise the packet delivery rate by replicating and spread copies of source packets in the networks, but it inevitably exhaust memory resources and network bandwidth. In this paper, we propose a network coding with limited buffer routing protocol based on two network models, single packet network model and multiple packets network model. When a buffer of a node is full, two packets in the buffer are chosen randomly and encoded linearly together into a packet to save buffer space and improve the performance in many-to-one communications. Moreover, in the transmitting stage of our network coding routing protocol, we proposed two efficient approaches that can enhance the efficiency of information exchange and packets transmission in communications of delay tolerant networks.","Title: A Game Theory Based Congestion Control Protocol for Wireless Personal Area Networks\nYear: 2015\n\nAbstract: In Wireless Sensor Networks (WSNs), the presence of congestion can increase the ratio of packet loss, energy consumption and reduce of the network throughput. Especially, this situation will be more complex in Internet of Things (IoT) environments, which is composed of thousands of heterogeneous nodes. In this paper, we address the congestion problem between child and parent nodes in RPL-enabled networks, which typically consist of low power and resource constraint devices. We use game theory strategy to design a parent-change procedure which decides how nodes changing their next hop node toward sink to mitigate the effect of network congestion. Comparing to the Contiki RPL implementation, the simulation results show that our protocol can achieve more than twofold improvement in packet loss rate and throughput with similar average hop count.","Title: An efficient routing algorithm based on segment routing in software-defined networking.\nYear: 2016\n\nAbstract: Software-defined networking (SDN) is an emerging architecture that offers advantages over traditional network architecture. Segment routing (SR) defines the path of information through the network via an ordered list of multi-protocol label switching (MPLS) mechanisms on the packet headers at the ingress device, and this system makes SDN routing management more simple and efficient. SR can also solve some scalability issues in SDN. In this paper, we propose a routing algorithm for SDN with SR that can meet the bandwidth requirements of routing requests. Our algorithm considers the balance of traffic load and reduces the extra cost of packet header size in a network. Simulation results show that the performance of our algorithm is better than that of previously developed algorithms in terms of the average network throughput and the average rejection rate of routing requests.","Title: Design and analysis of collision free MAC for wireless sensor networks with or without data retransmission.\nYear: 2017\n\nAbstract: In this paper, a new communication mechanism for IEEE 802.15.4 based Wireless Sensor Networks (WSNs) is designed to reduce the collisions and to prevent simultaneous data transmission by the nodes. Analytical models are designed for the uplink traffic in beacon-enabled slotted CSMA/CA with acknowledgements. In order to avoid the collisions and thereby the number of retransmissions, a new medium access control (MAC) protocol is designed. Beside, the current mechanism of IEEE 802.15.4 CSMA/CA is extended to develop the analytical models by including retransmission limits of the nodes with packet collision probability. Taking uplink traffic of the sensors, a Markov chain model is developed to analyze the energy consumption and throughput of the nodes and to study the impact of various network parameters such as the data rate, packet size and node numbers. The proposed models show that the throughput of the system is reduced and energy consumption is increased due to data retransmissions irrespective of the data rates.","Title: User satisfaction based resource allocation schemes for multicast in D2D networks.\nYear: 2017\n\nAbstract: The D2D communication has high potential to serve multiple users with high data rate within a proximity in the next generation cellular networks. In this paper, we consider a multicast scenario of D2D users where each user wishes to receive the same multicast data at varying data rates. Based on our best knowledge, finding an optimal solution to satisfy the user request in the said context requires unreasonable time. Therefore, we have proposed approximation algorithms with two objectives (i) maximize the satisfied throughput, (ii) maximize the number of satisfied users when the available resource blocks are limited. The simulation results show that the proposed algorithms offer a worst-case performance guarantee and outperform the other conventional schemes in terms of throughput, satisfied users count, and fairness.","Title: A Scalable And Bandwidth-Efficient Multicast Algorithm Based On Segment Routing In Software-Defined Networking\nYear: 2017\n\nAbstract: Software-Defined Networking (SDN) is an emerging architecture and offers advantages over traditional network architecture, while there exist some scalability challenges. In this paper, we propose a multicast routing algorithm for SDN with segment routing to serve the bandwidth requirement of a multicast routing request. Our algorithm considers the balance of traffic load for network resource of link bandwidth and node flow entries both. Simulation results show that the performance of our algorithm is better than previous works in terms of average network throughput and average rejection rate of routing requests. Besides, the results also show that our multicast architecture improve scalability problem of original SDN model in terms of number of flow entries used.","Title: Social activeness based relay selection: A game theoretic approach\nYear: 2017\n\nAbstract: D2D cooperative communication is one of the essential requirements of the next generation networks. As human beings carry D2D devices, their emotions also play a prime role in cooperative data exchange. Several earlier works have discussed the various social factors; none has considered the significance of multiple social networks a user can have contact with. In this paper, we leverage the social contacts of a user with various social networks to decide the next hop relay. We take into account the total friends and their contact duration of each social network to determine the relay that has the maximum potential to disperse the information. By considering these social aspects along with the physical parameters, we developed a utility function to model our problem as a relay selection game. We proved our game model as an exact potential game, which has Nash equilibrium. Simulation results show that the proposed method has better throughput when compared to the conventional methods.","Title: Probabilistic k-weighted coverage placement in wireless sensor networks.\nYear: 2017\n\nAbstract: In this paper, we study a new problem called probabilistic k-weighted coverage placement, which is a generalization of the Q-coverage placement. Q-coverage placement assumes that the monitored area has uniform coverage requirement: events within the monitored area should be detected with probability Q x 100% (i.e., detected by Q sensors), while probabilistic k-weighted coverage placement assumes that the monitored area has k-degrees of coverage requirement (i.e., k kinds of detection probability): events within distinct region of the monitored area are detected with distinct detection ability, i.e., one of the k kinds of detection probability. Besides, Q-coverage placement requires that the coverage requirement is integer multiple of 100% detection probability, while probabilistic k-weighted coverage placement allows coverage requirement to be non-integer multiple of 100% detection probability. We derive a lower bound on the number of sensors needed to satisfy the coverage requirement of a probabilistic k-weighted monitored area, and introduce a greedy algorithm to solve the problem.","Title: Resource Allocation Schemes for Revenue Maximization in Multicast D2D Networks.\nYear: 2017\n\nAbstract: Mobile users' service satisfaction plays a vital role in improving the revenue of telecom companies. When user data demands are uniform, satisfying the user requests is much easier than when demands are diverse. Yet, in a multicast scenario, each user may wish to view the same multicast data at different bit rates based on their own device capacities or resolutions. In this paper, we consider device-to-device (D2D) multicast users who may demand the multicast data at various rates, and in return, they offer different profits (revenue) to the telecom operator. Moreover, users may have different channel qualities from the base station, which will also affect the data rates. We show that satisfying the user requests to maximize the profit becomes NP-hard when the resource blocks are limited, and propose a greedy heuristic and two approximation algorithms to solve this problem. Besides, we consider an alternative objective of maximizing the number of satisfied users and propose a greedy heuristic algorithm for this variant. Our simulation results demonstrate that the proposed algorithms offer higher profit, throughput, and satisfy more users than the other candidate algorithms.","Title: Efficient TCAM Rules Distribution Algorithms in Software-Defined Networking.\nYear: 2018\n\nAbstract: In software-defined networking (SDN), network rules are installed in ternary content-addressable memory (TCAM). TCAM is a scarce and expensive resource which is a bottleneck for scaling SDN. Rule distribution is a strategy to solve the TCAM shortage problem, which decomposes a large table stored at network ingress into a number of smaller sub-tables and distributes them across network switches. Ru...","Title: Dynamic Spectrum Allocation Algorithms for Industrial Cognitive Radio Networks.\nYear: 2018\n\nAbstract: Irregular spectrum usage and spectrum scarcity in emergency situations is a common problem in industrial wireless networks. To enhance the dynamic spectrum usage, cognitive radio network (CRN) is introduced in various automotive industrial wireless applications named as industrial cognitive radio network (ICRN). However, establishing the control channel by using channel hopping mechanism in ICRN i...","Title: A Multi-Radio Rendezvous Algorithm Based on Chinese Remainder Theorem in Heterogeneous Cognitive Radio Networks.\nYear: 2018\n\nAbstract: In cognitive radio networks (CRNs), secondary users can utilize the temporary unused spectrum opportunistically without affecting the quality of services of the licensed users, also called primary users. It is a fundamental operation for a user to rendezvous with another user on the same channel and establish a communication link. Traditional rendezvous algorithms assume homogeneous CRNs and each ...","Title: An Enhanced Fast Multi-Radio Rendezvous Algorithm in Heterogeneous Cognitive Radio Networks.\nYear: 2018\n\nAbstract: In this paper, we propose a fast rendezvous algorithm for a heterogeneous cognitive radio network (CRN), where each user might have more than one radio. One of the well-known problems for most multiradio rendezvous algorithms in the literature is that they are not backward compatible to users with only one radio. To tackle this backward compatibility problem, our approach is a hierarchical constru...","Title: Improving Memory Traffic by Assembly-Level Exploitation of Reuses for Vector Registers\nYear: 2000\n\nAbstract: In this paper, we propose a compilation scheme to analyze and exploit the implicit reuses of vector register data. According to the reuse analysis, we present a translation strategy that translates the vectorized loops into assembly vector codes with exploitation of vector reuses. Experimental results show that our compilation technique can improve the execution time and traffic between shared memory and vector registers. Techniques discussed here are simple, systematic, and easy to be implemented in the conventional vector compilers or translators to enhance the data locality of vector registers.","Title: Performance evaluation of wireless sensor network with hybrid channel access mechanism\nYear: 2009\n\nAbstract: In this paper, a hybrid channel access mechanism is proposed for the wireless sensor network that considers the channel access procedure of IEEE 802.15.4 and combines the binary exponential backoff mechanism of IEEE 802.11 due to packet collision of nodes after successful channel assessment. Taking the backlogged nodes due to collision, an extended linear feedback model is developed and a discrete-time Markov chain model is designed to analyze the successful and failure probabilities of the system model of the wireless sensor network. Besides, an energy consumption model for the one hop wireless sensor network is developed based on our models and hybrid channel access mechanism. Extensive performance analysis are done to study the effect of binary exponential contention window on energy consumption of the nodes and it is verified that our simulation results totally match with the theoretical results for different size of contention windows and node numbers.","Title: Wildcard-rule caching and cache replacement algorithms in Software-Defined Networking.\nYear: 2017\n\nAbstract: Ternary Content Addressable Memory (TCAM) capacity problem is an important issue in Software-Defined Networking. Rule caching is an efficient technique to solve the TCAM capacity problem. However, there exists rule dependency problem in wildcard-rule caching technique. In this paper, we utilize cover-set method to solve the rule dependency problem and propose a wildcard-rule caching algorithm to cache rules into TCAM. In addition, we also propose a cache replacement algorithm considering both temporal and spatial localities. According to the simulation results, our wildcard-rule caching algorithm and cache replacement algorithm have better performance than previous works in terms of caching ratio and hit ratio, respectively.","Title: Spectrum Allocation with Guaranteed Rendezvous in Asynchronous Cognitive Radio Networks for Internet of Things\nYear: 2019\n\nAbstract: The massive usage of Internet-of-Things (IoT) devices in various smart applications enables spectrum scarcity issues. In order to enhance the dynamic spectrum capability, Cognitive Radio Network (CRN) is considered as a key technology to address the spectrum scarcity problem. However, the establishment of a common communication channel in CRN by considering the unlicensed heterogeneous devices in an asynchronous environment is a challenging problem. In this paper, a novel Asymmetric Asynchronous Channel Hopping (AACH) mechanism is designed, where secondary users have different sets of available channels and can enter into the network without any global clock synchronization. The proposed algorithms can guarantee the rendezvous within a small interval of time with minimum Inter Rendezvous Intervals (IRI). Simulation results show that the designed protocol outperforms over the existing channel hopping algorithms in terms of the degree of rendezvous, Average Time To Rendezvous (ATTR) and throughput.","Title: A Quasi-random Algorithm for Anonymous Rendezvous in Heterogeneous Cognitive Radio Networks.\nYear: 2019\n\nAbstract: The multichannel rendezvous problem that asks two secondary users to rendezvous on a common available channel in a cognitive radio network (CRN) has received a lot of attention lately. Most rendezvous algorithms in the literature focused on constructing channel hopping (CH) sequences that guarantee finite maximum time-to-rendezvous (MTTR). However, these algorithms perform rather poorly in terms of the expected time-to-rendezvous (ETTR) even when compared to the simple random algorithm. In this paper, we propose the quasi-random (QR) CH algorithm that has a comparable ETTR to the random algorithm and a comparable MTTR to the best bound in the literature. Our QR algorithm does not require the unique identifier (ID) assumption and it is very simple to implement in the symmetric, asynchronous, and heterogeneous setting with multiple radios. In a CRN with $N$ commonly labelled channels, the MTTR of the QR algorithm is bounded above by $9 M lceil n_1/m_1 rceil cdot lceil n_2/m_2 rceil$ time slots, where $n_1$ (resp. $n_2$) is the number of available channels to user $1$ (resp. 2), $m_1$ (resp. $m_2$) is the number of radios for user $1$ (resp. 2), and $M=lceil lceil log_2 N rceil /4 rceil *5+6$. Such a bound is only slightly larger than the best $O((log log N) frac{n_1 n_2}{m_1 m_2})$ bound in the literature. When each SU has a single radio, the ETTR is bounded above by $frac{n_1 n_2}{G}+9Mn_1n_2 cdot (1-frac{G}{n_1 n_2})^M$, where $G$ is the number of common channels between these two users. By conducting extensive simulations, we show that for both the MTTR and the ETTR, our algorithm is comparable to the simple random algorithm and it outperforms several existing algorithms in the literature.","Title: Collaboration Between Social Internet of Things and Mobile Users for Accuracy-Aware Detection\nYear: 2021\n\nAbstract: Social Internet of Things (SIoT) has become an emerging network paradigm, where IoT devices with Artificial Intelligence (AI) and social relations can automatically establish a collaborative group to identify events locally. On the other hand, mobile users can act as ubiquitous and versatile sensors to improve the accuracy of SIoT event detection. In this paper, we explore the SIoT Collaboration with Crowdsourcing (SCC) problem to jointly select SIoT devices and hire users to monitor events and locations with accuracy requirements, while minimizing the total SIoT communication and computation casts and the user hiring cost. We prove that SCC is NP-hard and cannot be approximated by any factor unless P = NP. Then, we propose a new algorithm, Accuracy- and Social-aware SIoT and User Selection (ASSUS), with the idea of Collaborative Tree (CT) and Accuracy Profit (AP), where CT exploits users' social relations to properly choose intermediate SIoTs. Simulation results manifest that ASSUS can effectively reduce more than 50% of the total cost compared with state-of-the-art algorithms.","Title: Cooperative Distributed Deep Neural Network Deployment with Edge Computing\nYear: 2021\n\nAbstract: Deep Neural Networks (DNNs) are widely used to analyze the abundance of data collected by massive Internet-of-Thing (IoT) devices. The traditional approaches usually send the data to the cloud and process the DNN inference on the powerful cloud servers but suffer from long network latency. Therefore, edge computing has emerged to reduce network latency by offloading the computation from the cloud to the edge. However, a single resource-constrained edge device is unable to process real-time DNN inference. Thus, we devise a collaborative edge computing system CoopAI to distribute DNN inference over several edge devices with a novel model partition technique to allow the edge devices to prefetch the required data in advance to compute the inference cooperatively in parallel without exchanging data. Subsequently, we present a new optimization problem to minimize the completion time of distributed DNN inference. An innovative algorithm is then proposed to intelligently partition the model into the proper number and sizes of blocks, deploy them on a suitable number of edge devices, and run them in different rounds. The numerical results manifest that our algorithm outperforms the traditional approach by 20%-30% on the completion time.","Title: Deep Learning for Ultra-Wideband Indoor Positioning\nYear: 2021\n\nAbstract: In recent years, the Ultra-wideband (UWB) system has been investigated for indoor localization and navigation by academia and industry. However, the UWB localization accuracy deteriorates when the signal propagates under severe non-line-of-sight (NLoS) conditions. We use two deep learning network models, the long short-term memory (LSTM) network and deep neural network (DNN), to analyze five diffe...","Title: UAV Deployment and IoT Device Association for Energy-Efficient Data-Gathering in Fixed-Wing Multi-UAV Networks\nYear: 2021\n\nAbstract: This work studies the deployment of multiple fixed-wing unmanned aerial vehicles (UAVs) for data-gathering from ground IoT devices and the corresponding device association policy. Each UAV is assumed to follow a circular flight trajectory above its responsible network area in order to stay afloat. The device association and the UAVs’ trajectory centers and radii are jointly optimized to maximize t...","Title: Distributed DRL-based Resource Allocation for Multicast D2D Communications\nYear: 2021\n\nAbstract: Device-to-device (D2D) communication is one of the promising solutions to improve spectrum efficiency and alleviate the mobile traffic explosion. However, interference mitigation and resource allocation in the underlying cellular network is a challenging task. In this paper, we propose a distributed deep reinforcement learning (DRL) based scheme to solve the interference mitigation and resource allocation problem. According to the channel status, each cellular user (CU) and D2D transmitter (D2D TX) will determine the appropriate reused channel and transmit power to maximize the system throughput. We propose a distributed DRL scheme and integrate two hotbooting algorithms into the scheme to improve the system throughput at the early stage of training. Simulation results show that the proposed distributed DRL with hotbooting outperforms the baselines regarding running time, message overhead, and throughput.","Title: Reinforcement based Communication Topology Construction for Decentralized Learning with Non-IID Data\nYear: 2021\n\nAbstract: Federated Learning (FL) allows Internet-of-Things (IoT) devices to train a global model collaboratively and circumvent the security issue. However, the current FL framework has three main drawbacks, the huge network overhead, single point of failure, and accuracy degradation in non-independent-and-identically-distributed (non-IID) data distribution. We propose a novel Deep Reinforcement Learning (DRL) based Decentralized Learning (DL) framework, Deep Select, to 1) reduce the network overhead of conventional FL, 2) construct a good communication topology adaptively to mitigate the effect of non-IID data, and 3) accelerate the DL training by balancing the effects of hitting time (HT) and data bias. Moreover, DeepSelect with a subtly-designed DRL agent is reusable with different levels of non-IID data distributions. To the best of our knowledge, this paper is the first one to indicate that proper neighbor selection for exchanging parameters (not raw data) can counterbalance the data bias's effect and improve the DL convergence with non-IID data. The experiment results show that DeepSelect can reduce 18%-51% training rounds than the other heuristics on FashionMNIST and CIFAR-10 with non-IID data distributions."],"string":"[\n \"Title: Unilateral Wakeup for Mobile Ad Hoc Networks\\nYear: 2011\\n\\nAbstract: Asynchronous wakeup schemes have been proposed for ad hoc networks to increase the energy efficiency of wireless communication. The basic idea is to allow a node to sleep when it is idle, and wakeup periodically to check if there are pending transmissions. In this paper we examine the applicability of asynchronous wakeup schemes to the Mobile Ad Hoc Networks (MANETs). We discover that, although it is desirable to have nodes with lower mobility to sleep more in reaction to the less-changing link states, in practice this is prohibited due to an unwanted tradeoff between the energy saving and in-time link discovery. All nodes in a network must stay awake frequently based on their highest possible moving speed in order to avoid network partition. To address this problem, we propose a new wakeup scheme, named Unilateral- (Uni-) scheme, for MANETs that allows nodes with slower moving speed to sleep more without losing the network connectivity. Theoretical analysis shows that the Uni-scheme can render up to 24% improvement in energy saving as compared with the previous arts.\",\n \"Title: A priority MAC protocol to support real-time traffic in ad hoc networks\\nYear: 2004\\n\\nAbstract: Carrier sense multiple access and its variants have been widely used in mobile ad hoc networks. However, most existing access mechanisms cannot guarantee quality for real-time traffic. This paper presents a distributed medium access control protocol that provides multiple priority levels for stations to compete for the wireless channel. One common channel is assumed to be shared by all stations. Stations are assumed to be able to hear each other (i.e., the network is fully connected). The channel is accessed by stations according to their priorities, and for stations with the same priority, they send frames in a round robin manner. The channel access procedure is divided into three stages: priorities classification period, ID initialization period, and transmission period. Simulation results indicate that our protocol provides high channel utilization and bounded delays for real-time frames.\",\n \"Title: Load-Balanced Trees for Data Collection in Wireless Sensor Networks\\nYear: 2012\\n\\nAbstract: In static wireless sensor networks, it is an important research issue to achieve effectively periodic data collection and prolong the network lifetime. In this paper, a distributed k-load-balanced tree scheme is proposed to prolong the network lifetime for periodic data collection. A k-load-balanced tree is a tree that the difference of the number of children of each two non-leaf nodes in a network is less than k. Each node chooses the node with the least current number of children and number of neighbor as parent for avoiding that the difference of the number of children of each two non-leaf nodes in a network is more than k. The simulation results show that our scheme can prolong the network lifetime and the network delay time is close to the result of centralized method.\",\n \"Title: Seamless channel transition for the staircase video broadcasting scheme\\nYear: 2004\\n\\nAbstract: In the literature, many broadcasting-based schemes have been proposed to efficiently support near-VOD services. However, none of these schemes allows the server to dynamically and seamlessly change the number of channels allocated to a video. Naively allocating a new set of channels for the transition could increase server's load, waste communication bandwidth, and even drain the channels of the system. In Tseng et al. (2000), it is shown how to enhance the Fast Broadcasting (FB) scheme for seamless channel transition. The problem remains open whether other broadcasting-based schemes can sustain seamless channel transition. In this paper, we show how to enhance the Staircase Broadcasting (SB) scheme so that a server can seamlessly increase or decrease the channels allocated to a video. The SB scheme has been proved to require significantly less buffering space than FB, while sustaining the same startup latency as FB. Detailed performance comparisons are presented to demonstrate the advantages of the proposed scheme.\",\n \"Title: A Distributed Query Protocol in Wireless Sensor Networks\\nYear: 2007\\n\\nAbstract: In wireless sensor networks, query execution over a specific geographical region is an essential function for collecting sensed data. However, sensor nodes deployed in sensor networks have limited battery power. Hence, the minimum number of connected sensor nodes that covers the queried region in a sensor network must be determined. This paper proposes an efficient distributed protocol to find a subset of connected sensor nodes to cover the queried region. Each node determines whether to be a sensing node to sense the queried region according to its priority. The proposed protocol can efficiently construct a subset of connected sensing nodes and respond the query request to the sink node. In addition, the proposed protocol is extended to solve the k-coverage request. Simulation results show that our protocol is more efficient and has a lower communication overhead than the existing protocol.\",\n \"Title: Data broadcasting and seamless channel transition for highly demanded videos\\nYear: 2000\\n\\nAbstract: One way to broadcast a popular video is to use a number of dedicated channels, each responsible for broadcasting some portion of the video periodically in a predefined way. The stress on the channels can be alleviated, and new viewers do not have to wait long to start their playback. Many approaches falling in this category have been proposed. One such scheme that interests us is the fast broadcasting (FB) scheme, which can broadcast a video using k channels by incurring at most O(D/2k) waiting time on new-coming viewers, where D is the length of the video. We consider a set of videos, each being broadcast by the FB scheme. Since the demand levels on these videos may change with time, it is sometimes inevitable to change the numbers of channels assigned to some videos. We propose a novel seamless channel transition enhancement on top of the FB scheme to dynamically change the number of channels assigned to a video on-the-fly. Clients currently viewing this video will not experience any disruption because of the transition. A channel allocation scheme is also proposed based on the arrival rates of videos to minimize the average waiting experienced by all viewers. From the system manager's point of view, the enhancement will make the FB scheme more attractive\",\n \"Title: Pair-wise path key establishment in wireless sensor networks\\nYear: 2007\\n\\nAbstract: When sensor networks deployed in unattended and hostile environments, for securing communication between sensors, secret keys must be established between them. Many key establishment schemes have been proposed for large scale sensor networks. In these schemes, each sensor shares a secret key with its neighbors via preinstalled keys. But it may occur that two end nodes which do not share a key with each other could use a secure path to share a secret key between them. However during the transmission of the secret key, the secret key will be revealed to each node along the secure path. Several researchers proposed a multi-path key establishment to prevent a few compromised sensors from knowing the secret key, but it is vulnerable to stop forwarding or Byzantine attacks. To counter these attacks, we propose a hop by hop authentication scheme for path key establishment to prevent Byzantine attacks. Compared to conventional protocols, our proposed scheme can mitigate the impact of malicious nodes from doing a Byzantine attack and sensor nodes can identify the malicious nodes. In addition, our scheme can save energy since it can detect and filter false data not beyond two hops.\",\n \"Title: An obstacle-free and power-efficient deployment algorithm for wireless sensor networks\\nYear: 2009\\n\\nAbstract: This paper proposes a robot-deployment algorithm that overcomes unpredicted obstacles and employs full-coverage deployment with a minimal number of sensor nodes. Without the location information, node placement and spiral movement policies are proposed for the robot to deploy sensors efficiently to achieve power conservation and full coverage, while an obstacle surrounding movement policy is proposed to reduce the impacts of an obstacle upon deployment. Simulation results reveal that the proposed robot-deployment algorithm outperforms most existing robot-deployment mechanisms in power conservation and obstacle resistance and therefore achieves a better deployment performance.\",\n \"Title: Increasing The Throughput Of Multihop Packet Radio Networks With Power Adjustment\\nYear: 2001\\n\\nAbstract: The Packet Radio Network (PRN) is an attractive architecture to support mobile and wireless communication. Although the code assignment problem has been studied extensively on PRN, we observe in this paper that the power control problem has been ignored by most works, but may have significant impact on performance. By power control, we mean that the transmission ranges of stations are tunable. We show given a PRN in which each host already received a code, how to adjust the powers of stations to control/improve the topology of the PRN without violating the original code assignment. Several schemes are proposed. Through simulations, we demonstrate that although the code assignment problem is NP-complete and thus computationally very expensive, using our power adjustment schemes can easily improve the network performance by about 20% with polynomial costs.\",\n \"Title: A Resource Allocation Scheme for Scalable Video Multicast in WiMAX Relay Networks\\nYear: 2013\\n\\nAbstract: This paper proposes the first resource allocation scheme in the literature to support scalable-video multicast for WiMAX relay networks. We prove that when the available bandwidth is limited, the bandwidth allocation problems of 1) maximizing network throughput and 2) maximizing the number of satisfied users are NP-hard. To find the near-optimal solutions to this type of maximization problem in polynomial time, this study first proposes a greedy weighted algorithm, GWA, for bandwidth allocation. By incorporating table-consulting mechanisms, the proposed GWA can intelligently avoid redundant bandwidth allocation and thus accomplish high network performance (such as high network throughput or large number of satisfied users). To maintain the high performance gained by GWA and simultaneously improve its worst case performance, this study extends GWA to a bounded version, BGWA, which guarantees that its performance gains are lower bounded. This study shows that the computational complexity of BGWA is also in polynomial time and proves that BGWA can provide at least 1/ρ times the performance of the optimal solution, where rho is a finite value no less than one. Finally, simulation results show that the proposed BGWA bandwidth allocation scheme can effectively achieve different performance objectives with different parameter settings.\",\n \"Title: Circuit-Switched Broadcast in Multi-Port 2D Tori\\nYear: 1999\\n\\nAbstract: . This paper studies the one-to-all broadcast in a circuit-switched2D torus of any size with ff-port capability. This is a generalization of theone-port and all-port models. Existing results, as compared to ours, canonly solve very restricted sizes of tori, and use more numbers of steps.1 IntroductionOne primary communication in an interconnection network is the one-to-allbroadcast, where a source node needs to send a message to all other nodes inthe network. This paper studies the...\",\n \"Title: Tolerating Faults in Faulty Hypercubes Using Maximal Fault-Free Subcube-Ring\\nYear: 1995\\n\\nAbstract: In this paper, we present a reconfiguration approach to identify the maximalfault-free subcube-ring for tolerating faults in injured hypercubes. The fault-freesubcube-ring is connected by a ring of fault-free subcubes with dilation 3. By exploitingthe size of fault-free subcubes as large as possible, the maximal fault-freesubcube-ring with higher processor utilization is obtained. Using this approach,we can tolerate more than n faults in n-dimensional hypercubes. To demonstratethe...\",\n \"Title: Ratio-based time synchronization protocol in wireless sensor networks\\nYear: 2008\\n\\nAbstract: Time synchronization plays a key role in the wireless sensor networks (WSNs). Time synchronization is realized by those messages that are time-stamped. But there are several delay times during transmission after time stamping. Most of them are uncertain and contribute directly to synchronization error. The uncertainties include send time, channel access time, transmission time, and receive time. In addition to the uncertainties, clock drift is also a main source of time synchronization error. In this paper, we present a time synchronization protocol that can be applied in the multi-hop WSNs. The proposed protocol estimates the clock drift between two nodes to keep them synchronized for duration after once synchronizing. It uses lower communication overhead and establishes more robust synchronization situations for all nodes in the network. By periodical re-synchronization, the un-synchronization conditions such as nodes failures or topology change can be easily overcome. We implement our protocol in the Berkeley MICAz platform. The experimenting scenarios are 5-node and 18-node multi-hop topologies, and the re-synchronization periods are 30-second and 300-second. The experiment results show that the average synchronization errors of all nodes run with our protocol are ranged within several micro-seconds which are better than the previous protocol.\",\n \"Title: Location-free topology control protocol in wireless ad hoc networks\\nYear: 2007\\n\\nAbstract: Topology control emphasizes the proper adjustment of the transmission power of each node in wireless mobile ad hoc networks. It not only saves power but also increases the system throughput by increasing the spatial reuse of communication channels. However, there is a hidden terminal problem at the medium access control (MAC) layer if we merely address the topology control issue at the network layer. This paper proposes a distributed protocol that deals with topology control at the network layer and at the same time overcomes the hidden terminal problem at the MAC layer. Each node in the networks determines its power for data transmission and control packets transmission according to the received beacon messages from its neighbors. The proposed protocol works without location information and use little control packet overhead to prevent potential collisions due to hidden terminals. Simulations show that our protocol significantly decreases the total power consumption in the networks and has a better network throughput compared to other protocols.\",\n \"Title: Routing with Hexagonal Virtual Coordinates in Wireless Sensor Networks\\nYear: 2007\\n\\nAbstract: Using geographic routing, like GPSR, is efficient for ad hoc and wireless sensor networks, but it requires that nodes be aware of their physical positions. However, if there are holes in the network, routing across holes in GPSR will lead to a lot of overloaded nodes in the boundaries of the holes. In this paper, we propose a distributed protocol, named the hexagonal virtual coordinate (HVC), for constructing a virtual coordinate system. After the HVC is constructed, the nodes in the network will be aware of relative coordinates among the landmarks through the HVC chart. Based on the HVC chart, a source node can find an auxiliary routing path to indicate the direction of the journey from the source to the destination. Simulation results show that our protocol can support geographic routing efficiently.\",\n \"Title: Selection of the first k largest processes in hypercubes\\nYear: 1989\\n\\nAbstract: In this paper, algorithms are proposed for finding the first k largest numbered processes in hypercubes with and without faulty nodes.\",\n \"Title: A load awareness medium access control protocol for single-hop wireless ad hoc networks\\nYear: 2008\\n\\nAbstract: A contention-based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA-CA), has excellent efficiency when the system is light loaded. The main drawback of such protocols is their inefficiency and unbounded delay when the system load is heavy. On the other hand, a contention-free MAC protocol, such as token passing, has a better and fair throughput when the system is heavy loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness single-hop wireless ad hoc MAC protocol (which is called the LA protocol) that exploits the benefits of both contention-based and contention-free protocols. A contention-based MAC protocol is used when the system is light loaded and a contention-free one is used otherwise. Our LA protocol, which operates in a distributed fashion and is fully compatible with the IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention-based protocol and the contention-free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols. Copyright © 2006 John Wiley & Sons, Ltd.\",\n \"Title: Scalable continuous object detection and tracking in sensor networks\\nYear: 2010\\n\\nAbstract: With the advancement of MEMS technologies, sensor networks have opened up broad application prospects. An important issue in wireless sensor networks is object detection and tracking, which typically involves two basic components, collaborative data processing and object location reporting. The former aims to have sensors collaborating in determining a concise digest of object location information, while the latter aims to transport a concise digest to sink in a timely manner. This issue has been intensively studied in individual objects, such as intruders. However, the characteristic of continuous objects has posed new challenges to this issue. Continuous objects can diffuse, increase in size, or split into multiple continuous objects, such as a noxious gas. In this paper, a scalable, topology-control-based approach for continuous object detection and tracking is proposed. Extensive simulations are conducted, which show a significant improvement over existing solutions.\",\n \"Title: GRID: A Fully Location-Aware Routing Protocol for Mobile Ad Hoc Networks\\nYear: 2001\\n\\nAbstract: mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to assist routing in such an environment is to use location information provided by positioning devices such as global positioning systems (GPS). In this paper, we propose a new routing protocol called GRID, which tries to exploit location information in route discovery, packet relay, and route maintenance. Existing protocols, as compared to ours, are either not location-aware or partially location-aware in that location knowledge is not fully exploited in all these three aspects. One attractive feature of our protocol is its strong route maintenance capability --- the intermediate hosts of a route can perform a \\\"handoff\\\" operation similar to that in cellular systems when it roams away to keep a route alive. This makes routes in the MANET more stable and insensitive to host mobility. Simulation results show that our GRID routing protocol can reduce the probability of route breakage, reduce the number of route discovery packets used, and lengthen routes' lifetime.\",\n \"Title: A distributed IP address assignment scheme in ad hoc networks\\nYear: 2008\\n\\nAbstract: In this paper, we present a scheme to assign IP address to each newly-joined node. Some nodes are assigned as coordinators, and are responsible for assigning an IP address to a new node in the network. A new node will use the exchanged hello messages to find the closest coordinator and obtain a new IP address from that coordinator. In order to efficiently maintain the coordinators驴 IP-address pools, the distributed coordinators are organized in a tree topology, called a virtual C-tree, by exchanging hello messages. Simulation results show that our proposed scheme has a low latency for obtaining a new IP address, and that it can efficiently maintain consistent IP-address pools.\",\n \"Title: Cache-Based Routing for Vehicular Ad Hoc Networks in City Environments\\nYear: 2010\\n\\nAbstract: Most of routing protocols in VANETs are position-based due to their well scalability. The forwarding decisions of such protocols are simply based on the location information of forwarders' neighborhood and the destination node. Due to high mobility of vehicles, location-service protocols are required to provide the destination location. Location services protocols can be categorized as flooding-based and quorum-based. They are unrealistic for VANETs. In the former approaches, global network flooding require extreme high cost, while in the latter approaches, quorums' hand-off is impossible because of high volume of exchange data. In this paper, we present a routing by utilizing locality of vehicles' traces (i.e., left location information). Besides, by the aid of high mobility of vehicles and news exchange (new information about vehicles' location), vehicles' location information can be spread to improve the possibility of meeting a vehicle which has the location information of the destination. Our protocol is realistic and practical because neither global network flooding nor quorums are required. The simulation results show that our protocol works efficiently for VANETs in city environments and has higher successful query rate and lower cost.\",\n \"Title: Balanced spanning trees in complete and incomplete star graphs\\nYear: 1996\\n\\nAbstract: Efficiently solving the personalized broadcast problem in an interconnection network typically relies on finding an appropriate spanning tree in the network. In this paper, we show how to construct in a complete star graph an asymptotically balanced spanning tree, and in an incomplete star graph a near-balanced spanning tree. In both cases, the tree is shown to have the minimum height. In the literature, this problem has only been considered for the complete star graph, and the constructed tree is about 4/3 times taller than the one proposed in this paper\",\n \"Title: Fault-tolerant parallel k selection algorithm in n-cube networks\\nYear: 1991\\n\\nAbstract: In this paper, a parallel algorithm to select the first k largest numbered processes in n-cube networks is proposed. The proposed algorithm can tolerate at most n - 1 faults. The time complexity of this algorithm is 0(max(kn, n2)).\",\n \"Title: Design and implementation of ad hoc classroom and eSchoolbag systems for ubiquitous learning\\nYear: 2002\\n\\nAbstract: This paper describes the design and implementation of a learning technology project. The purpose of this project is to develop advanced wireless technologies for building an ad hoc classroom in order to contrive a modern and new learning environment. A wireless platform is developed for teacher and students to establish a classroom dynamically irrespective of location and time bounds. As supported in a traditional classroom, we develop information technology to provide the teacher with teaching aids, such as blackboard, board rubber, colored chalk, microphone, voice recorder, video recorder, and so on, for course teaching and discussions in an ad hoc classroom. In addition, we provide students with an electronic schoolbag (or eSchoolbag) which packs electronic book, notebook, parents contact book, pencil case, writing materials, sheets, calculator, address book, and so on. Taking lessons in a lively, vivid, and new learning environment, students are expected to enhance their learning performance without any burden like attending classes physically. Moreover students get more flexible scope of learning at a convenient time.\",\n \"Title: Unilateral Wakeup for Mobile Ad Hoc Networks with Group Mobility\\nYear: 2013\\n\\nAbstract: Asynchronous wakeup schemes have been proposed for ad hoc networks to increase the energy efficiency of wireless communication. The basic idea is to allow a node to sleep when it is idle, and wakeup periodically to check if there are pending transmissions. In this paper, we examine the applicability of asynchronous wakeup schemes to the Mobile Ad Hoc NETworks (MANETs). We discover that, although it is desirable to have nodes with lower mobility to sleep more in reaction to the less-changing link states, in practice this is prohibited due to an unwanted tradeoff between the energy saving and in-time link discovery. All nodes in a network must stay awake frequently based on their highest possible moving speed to avoid network partition. To address this problem, we propose a new wakeup scheme, named Unilateral- (Uni-) scheme, for MANETs that allows nodes with slower moving speed to sleep more without losing the network connectivity. The Uni-scheme supports both the entity mobility and group mobility of nodes, thus has broad applicability. Theoretical analysis and simulation are conducted and show that the Uni-scheme can render significant energy saving as compared with the previous arts.\",\n \"Title: An on-demand, link-state, multi-path QoS routing in a wireless mobile ad-hoc network\\nYear: 2004\\n\\nAbstract: The peer-to-peer multimedia applications have recently generated much interest in wireless network infrastructure with supporting the quality-of-service (QoS) communications. In this paper, we propose a new on-demand QoS routing, namely link-state multi-path QoS routing, protocol in a wireless mobile ad-hoc network (MANET). Our proposed scheme offers a bandwidth routing protocol for QoS support in a multihop mobile network. Our QoS routing protocol determines the end-to-end bandwidth calculation and bandwidth allocation at the destination. Our protocol collects link bandwidth information from source to destination in order to construct a network topology with the information of link bandwidth at the destination. To satisfy a given bandwidth requirement, the bandwidth calculation of the QoS route are determined at the destination to accurately determine the QoS uni-path or multi-path route depending on the status of network bandwidth. Our routing scheme may offer a multi-path route if a MANET with the insufficient network bandwidth, and provide a uni-path route if the network bandwidth is sufficient. The destination eventually determines the QoS multi-path routes and replies to the source host to perform the bandwidth reservation. Our routing scheme obviously improves the success rate of identifying a QoS route, and the simulation result demonstrates this improvement.\",\n \"Title: Efficient path planning and data gathering protocols for the wireless sensor network\\nYear: 2010\\n\\nAbstract: Wireless sensor network is commonly used to monitor certain region and to collect data for several applications. Normally, in wireless sensor network, data are routed in a multi-hop fashion towards a static sink. In this scenario, nodes closer to the sink become heavily involved in packet forwarding and their battery power is exhausted quickly. In this paper, an Infrastructure based Data Gathering Protocol (IDGP) and a Distributed Data Gathering Protocol (DDGP) are proposed to plan the data gathering path for a mobile sink. A k-hop relay mechanism is introduced to limit the number of hops for routing data to a mobile sink. In order to increase the efficiency of the data gathering, a cooperative environment among the sensor nodes and the mobile robot is proposed to formulate the data gathering path. Simulation results show that our data gathering protocols enable the nodes to transmit data with least number of hops and simultaneously reduce the data gathering path length traced by the mobile sink.\",\n \"Title: Location-based IP assignment protocol for ad hoc networks\\nYear: 2006\\n\\nAbstract: In this paper, we propose a location-based IP assignment protocol. We assume that a mobile host knows its current physical location; thus, this location information can be exploited to facilitate IP assignment. We divide the entire network into several disjoint and same-size cells and each cell has a coordinator to assign and maintain the available IP addresses. With location information for each host, the scheme proposed in this paper can avoid the problems of network partitions and mergers. Simulation results show the IP addresses can be fully utilized and that the control overhead and latency time are not affected by the mobility speed\",\n \"Title: Partitioning and mapping of nested loops for linear array multicomputers\\nYear: 1995\\n\\nAbstract: In distributed-memory multicomputers, minimizing interprocessor communication is the key to the efficient execution of parallel programs. In order to reduce the amount of communication overhead, parallel programs on multicomputers must be carefully scheduled by parallelizing compilers. This paper proposes some compilation techniques for partitioning and mapping nested loops with constant data dependences onto linear array multicomputers. First, a systematic partition strategy is proposed to project ann-dimensional computational structure, representing ann-nested loop, onto a line to form a one-dimensional projected structure with low communication overhead. Then, a mapping algorithm is proposed for mapping the partitioned loops onto linear arrays in a way that balances the workload and minimizes the communication cost among processors. Finally, parallel execution codes can be automatically generated for such linear array multicomputers.\",\n \"Title: Efficient Single-Node Broadcast In Switched-Based Network Of Workstations With Network Partitioning\\nYear: 2001\\n\\nAbstract: This paper proposes two efficient single-node broadcasting schemes for network of workstations (NOW) based on a network-partitioning concept. To broadcast a message, the scheme works in three phases. First, we partition the network into two sub-networks(data-distributed networks, DDN). The broadcast message is evenly divided into two sub-messages, each being sent to one representative node in each subnetwork. Second, each sub-message is distributed in its subnetwork independently. Finally, through a sub-message combination step, each node will obtain the whole broadcast message. Two network-partitioning schemes, namely 0-1 partitioning and odd-even partioning, are proposed. Through simulations on irregular and regular networks, we confirm the average latency of these schemes achieve performance improvement compared with the optimal broadcast scheme [7].\",\n \"Title: An Anonymous Path Routing (APR) Protocol for Wireless Sensor Networks\\nYear: 2011\\n\\nAbstract: How to secure data communication is an important problem in wireless sensor networks (WSNs). General solutions to the problem are to encrypt the packet payload with symmetric keys. But those solutions only prevent the packet content from being snooped or tampered. Adversaries still can learn of network topology by the traffic analysis attack for starting devastating attacks such as the denial-of-service attack and the like. In this paper, we propose an anonymous path routing (APR) protocol for WSNs. In APR, data are encrypted by pair-wise keys and transmitted with anonyms between neighboring sensor nodes and anonyms between the source and destination nodes of a multi-hop communication path. The encryption prevents adversaries from disclosing the data, and the anonymous communication prevents adversaries from observing the relation of the packets for further attacks. We implement APR on the MICAz platform to evaluate its overheads for demonstrating its applicability in practical WSNs.\",\n \"Title: An Efficient Channel Allocation Technique for Multiple Videos-on-Demand\\nYear: 2003\\n\\nAbstract: In this paper, we describe our work on developing an eLearning video database system. The eLearning video database provides a temporal modeling framework for describing eLearning video data and it supports data distribution by applying vertical class ...\",\n \"Title: Adaptive route-sharing protocol for data collection in Wireless Sensor Networks\\nYear: 2012\\n\\nAbstract: A Wireless Sensor Network (WSN) comprises a large number of sensor nodes and a few sink nodes. When multiple sink nodes are interested in collecting the readings of the same monitoring region, it is conducive to exploit the sharing route to save bandwidth and power consumption and prolong WSNs lifetime. This paper proposes a Dynamic Route-Sharing Protocol (DRSP), which constructs sharing routes based on different attributes (for example, frequency, packet length or delay time) of the commands requested from different sink nodes. The proposed DRSP dynamically adjusts data transmission route to achieve the goals of routes sharing and route length reduction. The simulation study shows that DRSP saves more energy and bandwidth consumptions than the existing work and thus prolongs the WSNs lifetime.\",\n \"Title: Reducing Cache Conflicts by Multi-Level Cache Partitioning and Array Elements Mapping\\nYear: 2000\\n\\nAbstract: This article presents an algorithm to reduce cache conflicts and improve cache localities. The proposed algorithm analyzes locality reference space for each reference pattern, partitions the multi-level cache into several parts with different sizes, and then maps array data onto the scheduled cache positions to eliminate cache conflicts. A greedy method for rearranging array variables in declared statement is also developed, to reduce the memory overhead for mapping arrays onto a partitioned cache. Besides, loop tiling and the proposed schemes are combined to exploit opportunities for both temporal and spatial reuse. Atom is used as a tool to develop a simulation of the behavior of the direct-mapping cache to demonstrate that our approach is effective at reducing number of cache conflicts and exploiting cache localities. Experimental results reveal that applying the cache partitioning scheme can greatly reduce the cache conflicts and thus save program execution time in both single-level cache and multi-level cache hierarchies.\",\n \"Title: Data mapping of linear programming on fixed-size hypercubes\\nYear: 1990\\n\\nAbstract: Although many solution methods are available for the linear programming problem, the simplex method is undoubtedly the most widely used one for its simplicity. In this paper, we propose an implementation of the simplex method on fixed-size hypercubes. A partitioning technique and a mapping technique are presented to fit large-size problem instances into relatively small-size hypercubes. Two cases, pipelined broadcasting allowed and pipelined broadcasting not allowed, are considered. We show that the proposed implementation achieves the linear speedup asymptotically for both cases. Also, under the given mapping method, we discuss how to partition data so as to minimize the total run time and the communication time. We derive sufficient conditions for optimal partitionings. These sufficient conditions are helpful to obtain better partitionings. The optimal partitioning is obtained for a special case.\",\n \"Title: Probabilistic Coverage Preserving Protocol With Energy Efficiency In Wireless Sensor Networks\\nYear: 2007\\n\\nAbstract: In this paper, we propose a k-coverage preserving protocol to achieve energy efficiency while ensuring the required coverage. In our protocol, we try to select a minimal active set of sensor nodes to reach energy conservation and maintain a complete area k-coverage. We model this problem as a minimum set cover problem and solve it by using a heuristic greedy algorithm. Based on the k-coverage preserving protocol, we then propose a protocol to deal with the probabilistic k-coverage requirement, in which each sensor could be assumed to be able to detect a nearby event with a certain probability. In the probabilistic k-coverage protocol, any point in the monitoring region can be sensed by at least k sensor nodes no lower than a confidence probability. Finally, we evaluate the performance of our protocols with simulations.\",\n \"Title: Modeling IEEE 802.15.4 based wireless sensor network with packet retry limits\\nYear: 2008\\n\\nAbstract: In this paper, an analytical model for the beacon-enabled slotted CSMA-CA mechanism of IEEE 802.15.4 wireless sensor network is designed. The current mechanism of IEEE 802.15.4 CSMA-CA is extended to include the retransmission limit of the nodes with packet collision probability. A three-dimensional discrete time Markov chain model for the uplink traffic of wireless sensor network is designed to analyze the energy consumption and throughput of the nodes under unsaturated traffic conditions. The energy consumption and throughput are analyzed for different node numbers and data rates to estimate the possible number of nodes for the better performance in terms of throughput.\",\n \"Title: A Fully Distributed Multi-Channel Mac Protocol For Ad Hoc Networks Based On Location Information\\nYear: 2006\\n\\nAbstract: This paper proposes a distributed multi-channel MAC protocol which is an extension of our early work GRID [1]. GRID is characterized by the following features: (i) it integrates a location-aware channel assignment, (ii) it follows an \\\"on-demand\\\" style to access the medium, (iii) the number of channels required is independent of the network topology, and (iv) no form of clock synchronization is required. The proposed protocol wants to further improve the GRID in two parts. First, we propose a fully distributed medium access mechanism without using a single control channel such that all of the network traffic can be distributed evenly over all data channels. Therefore, the network throughput will be increased significantly. Second, we can set the more suitable transmission range and GRID size by considering the factors of host density and packet arrival rate of the network within an specified area. Thus, all of channels will be reused more efficiently than GRID. Simulation results show that the throughput of our protocol is superior to GRID and IEEE 802.11.\",\n \"Title: Performance Analysis of Multistage Interconnection Networks with Hierarchical Requesting Model\\nYear: 1988\\n\\nAbstract: Analyzes the performance of the multistage interconnection networks (MINs) for interconnecting N processors or N processors to N commonly shared memory modules in a multiprocessor system. A general model, called hierarchical requesting model, has been proposed. The performance of the MINs with respect to their memory bandwidth is analyzed and is compared to that of a crossbar under the proposed model. Based on the analytical results, the authors present a task allocation strategy to increase the memory bandwidth of the MINs.\",\n \"Title: Hole detection and boundary recognition in wireless sensor networks\\nYear: 2009\\n\\nAbstract: Coverage holes may exist in wireless sensor networks (WSNs) due to presence of obstacles or invalid sensor nodes in the sensing field. Normally, the holes make the data routing failure when the nodes transmit their data back to the sink. In this paper, distributed protocols are developed to identify the boundary nodes surrounding the holes of the sensing filed in WSNs without using any location information. Experimental results demonstrate that our algorithm can precisely and correctly identify the boundary nodes even in sparsely sensors deployed regions. Besides, our algorithm can give better performance in terms of control packet overhead and simulation time as compared to previous work.\",\n \"Title: A Distributed Location Estimating Algorithm for Wireless Sensor Networks\\nYear: 2006\\n\\nAbstract: The location estimation is a fundamental and essential issue for wireless sensor networks(WSNs). In this paper, we assume that only a few sensor nodes (named as beacon nodes) get their locations by Global Positioning System (GPS) and the remaining nodes without GPS (named as normal nodes) need to estimate their own locations by gathering the nearby neighboring information. Existing works are either too costly or not accurate enough. To improve previous works, we propose a distributed location estimation algorithm for WSNs. In our algorithm, each node without location information only needs to collect the location information of neighboring nodes and use simple computation to estimate its location. Besides, we improve the accuracy of the normal node's estimative region by discarding the communication area of the beacon node (named as the farther neighboring beacon node), which does not cover the normal node, from the original estimative region. We derive some rules to adjust the estimative region according to the relative location of the normal node and the farther neighboring beacon node. Simulation results show that the proposed algorithm achieves better accuracy of estimative locations.\",\n \"Title: Limited mobility coverage and connectivity maintenance protocols for wireless sensor networks\\nYear: 2011\\n\\nAbstract: Coverage and connectivity maintenance is an important research issue in wireless sensor networks, as sensors are deployed randomly over the monitoring region in large numbers. In the post deployment scenario, existing coverage or connectivity of the network is disturbed due to predictable or unpredictable death of the nodes and maintenance of the network manually is difficult due to physical condition of the monitoring region. In this paper, potential connectivity and coverage maintenance algorithms for the wireless sensor networks are proposed that let the sensors work alternatively by identifying the redundant sensing regions in the post deployed scenarios and maintain the network with limited mobility. Decision of mobility of the nodes among immediate neighbors of a dead node is totally autonomous and distributed, and it is made to maintain the network without disturbing the existing coverage and connectivity. Performance evaluation of our protocols shows that the average mobility distance and energy consumption of the nodes are limited to maintain the coverage and connectivity. Moreover, the proposed algorithms could be worked for the communication range (R\\\"c) of a node is equal to sensing range (R\\\"s) or for R\\\"c\",\n \"Title: Efficient broadcast in heterogeneous networks of workstations using two sub-networks\\nYear: 2005\\n\\nAbstract: This paper presents efficient algorithms for broadcasting on heterogeneous switch-based networks of workstations (HNOW) by two partitioned sub-networks. In an HNOW, many multiple speed types of workstations have different send and receive overheads. Previous research has found that routing by two sub-networks in a NOW can significantly increase system's performance (Proc. 10th International Conference on Computer Communications and Networks, pp. 68-73, 2001). Similarly, EBS and VBBS (Proc. 8th IEEE International Symposium on Computer and Communication, pp. 1277-1284, (2003)), designed by applying the concept of fastest nodes first, can be executed in O(nlog(n)) time, where n is the number of workstations. This paper proposes two schemes TWO-EBS and TWO-VBBS for broadcasting in an HNOW. These two schemes divide an HNOW into two sub-networks that are routed concurrently and combine EBS and VBBS to broadcast in an HNOW. Based on simulation results, TWO-VBBS outperforms EBS, VBBS, VBBSWF (Proc. 8th IEEE International Symposium on Computer and Communication, pp. 1277-1284, (2003)), the postorder recursive doubling (Proc. Merged IPPS/SPDP Conference, pp. 358-364, (1998)), and the optimal scheduling tree (Proc. Parallel and Distributed Processing Symposium, Proc. 15th International (2001)) generated by dynamic programming in an HNOW.\",\n \"Title: Initialization protocols for IEEE 802.11-based ad hoc networks\\nYear: 2002\\n\\nAbstract: Leader election and initialization are two fundamental problems in mobile ad hoc networks (MANETs). The leader can serve as a coordinator in the MANETs and the initialization protocol can assign each host a unique and short id. We know that none of the research on initialization for IEEE 802.11-based MANETs has been done. Here, we propose two contention-based leader election and initialization protocols for IEEE 802.11-based single-hop MANETs. Simulation results show that our protocols are efficient.\",\n \"Title: Typhoon: Resource Sharing Protocol for Metropolitan Vehicular Ad Hoc Networks.\\nYear: 2010\\n\\nAbstract: In this paper, we propose a realistic resource sharing protocol for VANET. The main idea of our protocol comes from typhoons. Typhoons move according to their eyes' mobility, i.e., quorums which are responsible for a given resource holder/requester \\\"moves\\\" according to the resource holder's/requester's mobility. Our protocol exploits spatial locality between requesters and resource holders. When resource requesters get their desired resources, they are able to be new resource holders. For hot-resources, requesters are so numerous that the spatial locality is much enhanced over time. Besides, lots of applications (e.g., available parking slot information) in VANET are location-aware which have spatial locality between requesters and resource holders. By the aid of the spatial locality, resource holders/requesters share/query sources in their vicinity in our protocol. Simulation results show that our protocol has lower search latency and well scalability comparing to the previous work. Besides, due to that the spatial locality is enhanced over time, successful rate increases over time.\",\n \"Title: Performance analysis of multiple bus interconnection networks with hierarchical requesting model\\nYear: 1991\\n\\nAbstract: The authors study the performance of multiprocessor systems employing multiple buses as the interconnection networks under a nonuniform requesting model, called the hierarchical requesting model. The effective memory bandwidth is chosen as the performance measure. The networks investigated include multiple bus networks with full bus-memory connection, multiple bus networks with single bus-memory connection, and multiple bus networks with partial bus-memory connection. The authors also propose a type of multiple bus network with partial bus-memory connection, called partial bus networks with K classes. The N costs and fault-tolerant capabilities of the multiple bus networks are also evaluated and compared to one another. It is shown that the partial bus networks with K classes are useful in applications requiring high performance and degree of fault tolerance with moderate cost\",\n \"Title: A frequency-aware data-centric mechanism for wireless sensor networks\\nYear: 2010\\n\\nAbstract: Wireless sensor networks (WSNs) are characterized by their low bandwidth, limited energy, and largely distributed deployment. To reduce the flooding overhead raised by transmitting query and data information, several data-centric storage (DCS) mechanisms are proposed. However, the locations of these data-centric nodes significantly impact the power consumption and efficiency for information queries and storage capabilities, especially in a multi-sink environment. This paper proposes a novel dissemination approach, which is namely the dynamic data-centric routing and storage mechanism (DDCRS), to dynamically determine locations of data-centric nodes according to sink nodes' location and data collecting rate and automatically construct shared paths from data-centric nodes to multiple sinks. To save the power consumption, the data-centric node is changed when new sink nodes participate when the WSNs or some queries change their frequencies. The simulation results reveal that the proposed protocol outperforms existing protocols in terms of power conservation and power balancing. Copyright © 2009 John Wiley & Sons, Ltd. The proposed dynamic data-centric routing and storage mechanism (DDCRS) considers multiple sinks with different query frequencies. DDCRS dynamically changes the locations of data-centric nodes and constructs shared paths from data-centric node to multiple sinks for energy conservation.\",\n \"Title: The broadcast storm problem in a mobile ad hoc network\\nYear: 1999\\n\\nAbstract: Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in par- ticular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broad- casting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we refer as the broadcast storm problem. In this paper, we iden- tify this problem by showing how serious it is through anal- yses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroad- casts to alleviate this problem. Simulation results are pre- sented, which show different levels of improvement over the basic flooding approach.\",\n \"Title: The broadcast storm problem in a mobile ad hoc network\\nYear: 2002\\n\\nAbstract: Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in particular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broadcasting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we call the broadcast storm problem. In this paper, we identify this problem by showing how serious it is through analyses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcasts to alleviate this problem. Simulation results are presented, which show different levels of improvement over the basic flooding approach.\",\n \"Title: An optimal broadcasting algorithm without message redundancy in star graphs\\nYear: 1995\\n\\nAbstract: Based on the V.E. Mendia and D. Sarkar's algorithm (1992), we propose an optimal and nonredundant distributed broadcasting algorithm in star graphs. For an n-dimensional star graph, our algorithm takes O(n log2 n) time and guarantees that all nodes in the star graph receive the message exactly once. Moreover, broadcasting m packets in a pipeline fashion takes O(m log2 n+n log2 n) time due to the nonredundant property of our broadcasting algorithm\",\n \"Title: Target tracking and boundary node selection algorithms of wireless sensor networks for internet services\\nYear: 2013\\n\\nAbstract: Wireless sensor network (WSN) is an integral part of Internet of Things (IoT), in which sensors can be used to keep track with interesting targets under surveillance. Target tracking is one of the important research issues, where sensors are deployed in many applications such as campus security, surveillance, habitat and battle field monitoring. Information can be forwarded in an ad hoc multi-hop fashion via internet to monitor a specific region and can form a ubiquitous network for several internet services. In this paper, Sequential Boundary Node Selection (SBNS) and Distributed Boundary Node Selection (DBNS) algorithms are proposed to find out the boundary nodes of the wireless sensor network. Besides, a target tracking protocol is proposed to detect the entry and exit of the targets using those boundary nodes. Simulation results show that the selection of boundary nodes in our protocol is almost close to the optimal one and the time of selecting boundary nodes would not increase rapidly, with increase in the size of the deployed nodes.\",\n \"Title: Design and implementation of a distributed file system\\nYear: 1991\\n\\nAbstract: SUMMARY We introduce a new model for replication in distributed systems. The primary motivation for replication lies in fault tolerance. Although there are different kinds of replication approaches, our model combines the advantages of modular redundancy and primary-stand-by approaches to give more flexibility with respect to system configuration. To implement such a model, we select the IBM PC-net with MS-DOS environment as our base. Transparency as well as fault-tolerance file access are the highlights of our system design. To fulfil these requirements, we incorporate the idea of directory-oriented replication and extended prefix tab/es in the system design. The implementation consists of a command shell, a DOS manager, and a recovery manager. Through this design, we can simulate a UNIX-like distributed file system whose function is compatible with MS-DOS.\",\n \"Title: Design and implementation of a smart mobile robot\\nYear: 2005\\n\\nAbstract: Most wireless sensor networks consist of a large number of static, low-power, short-lived, and unreliable sensors. In this paper, we considered sensor networks consisting of both static and mobile nodes. Integrating both types of devices enables new applications, such as nodes replacement, hole and partition recovery, and autonomous deployment and redeployment. We designed a smart mobile robot and implemented an application of nodes replacement to demonstrate its use, via our nodes replacement algorithm. In this algorithm, the mobile robots can navigate towards low-energy sensor nodes and replace them automatically, with new sensor nodes, having no location information. The navigation algorithm is based on received signal strength between the mobile robot and the communicating node. The experimental results confirm that the mobile robots successfully achieved their assigned tasks.\",\n \"Title: A group-based multi-channel MAC protocol for wireless ad hoc networks\\nYear: 2007\\n\\nAbstract: When we exploit multiple channels in MAC protocol, we can achieve a higher network throughput than using one single channel due to that multiple transmissions can take place simultaneously. In this paper, we proposed a novel group-based multichannel MAC protocol which cannot only utilize multiple channels to transmit data packets but allow using multiple channels to propagate control packets. The protocol we presented is simple and suitable for wireless ad hoc networks with multiple available channels. The simulation results show that our protocol has the superior performances in network throughput to previous work.\",\n \"Title: Partitioning and Mapping Nested Loops on Multiprocessor Systems\\nYear: 1991\\n\\nAbstract: A method for executing nested loops with constant loop-carried dependencies in parallelon message-passing multiprocessor systems to reduce communication overhead is presented. In the partitioning phase, the nested loop is divided into blocks that reduce the interblock communication, without regard to the machine topology. The execution ordering of the iterations is defined by a given time function based on L. Lamport's (1974) hyperplane method. The iterations are then partitioned into blocks so that the execution ordering is not disturbed, and the amount of interblock communication is minimized. In the mapping phase, the partitioned blocks are mapped onto a fixed-size multiprocessor system in such a manner that the blocks that have to exchange data frequently are allocated to the same processor or neighboring processors. A heuristic mapping algorithm for hypercube machines is proposed.\",\n \"Title: Decentralized token-CSMA/CD protocol for integrated voice/data LANs\\nYear: 1991\\n\\nAbstract: In this paper we propose a decentralized protocol for integrated voice and data local area networks. This protocol is based on a hybrid token-CSMA/CD protocol which combines all the merits of the CSMA/CD network and the token-passing network. We apply the hybrid protocol to voice and data individually, and offer two implicit tokens, one voice token and one data token, to achieve the priorities requirements. The voice transmission follows the token-passing protocol with a contention-resolution mechanism. It enforces a bounded delay to guarantee the real-time delivery for voice. This hybrid protocol will serve data of the low priority as fairly as best. To evaluate the protocol's performance, analytical formulations are derived. Numerical results are obtained for the throughput as well as the mean packet delay.\",\n \"Title: Interest-Based Lookup Protocols for Mobile Ad Hoc Networks\\nYear: 2005\\n\\nAbstract: In this paper, we propose two interest-basedbandwidth-efficient lookup protocols, simple lookup protocol and advanced lookup protocol, for mobile environments. A peer willing to search files broadcasts a query message with keywords relevant to its interests to its neighbors in the transmission range, and only those neighbors also interested in the query forward. Simulation results show that our protocols have higher success rate and raise the scalability and bandwidth efficiency comparing to the previous work. Besides, our protocols can avoid selfish behaviors, since the behavior of forwarding queries benefits not only the source node but also the forwarding node.\",\n \"Title: Cooperative routing protocol in cognitive radio ad-hoc networks\\nYear: 2012\\n\\nAbstract: Cognitive radio (CR) technology enables the opportunistic use of the vacant licensed frequency bands, thereby improving the spectrum utilization. Therefore, considering end-to-end throughput in CR ad-hoc networks is an important research issue because the availability of local spectrum resources may change frequently with the time and locations. In this paper, we propose a cooperative routing protocol in CR ad-hoc networks. An on-demand routing protocol is used to find an end-to-end minimum cost path between a pair of source and destination. The simulation results show that our proposed cooperative routing protocol not only obtains higher end-to-end throughput, but also reduces the end-to-end delay and the amount of control messages compared to previous work.\",\n \"Title: Adaptive k-coverage contour evaluation and deployment in wireless sensor networks\\nYear: 2013\\n\\nAbstract: The problem of coverage is a fundamental issue in wireless sensor networks. In this article, we consider two subproblems: k-coverage contour evaluation and k-coverage rate deployment. The former aims to evaluate, up to k, the coverage level of any location inside a monitored area, while the latter aims to determine the locations of a given set of sensors to guarantee the maximum increment of k-coverage rate when they are deployed into the area. For the k-coverage contour evaluation problem, a nonuniform-grid-based approach is proposed. We prove that the computation cost of our approach is at most the square root of existing solutions. Based on our k-coverage contour evaluation scheme, a greedy k-coverage rate deployment scheme (k-CRD) is proposed, which is shown to be an order faster than existing studies for k-coverage rate deployment. The k-CRD can incorporate two different heuristics to further reduce its running time. Simulation results show that k-CRD with these heuristics can be significantly more time efficient without causing much degradation in the coverage rate of final deployment.\",\n \"Title: An efficient MAC protocol with cooperative retransmission in mobile ad hoc networks\\nYear: 2012\\n\\nAbstract: In emerging wireless networks, cooperative retransmission is employed to replace packet retransmission between a pair of sender and receiver with poor channel condition. A cooperative MAC protocol which utilizes such benefit is proposed in this paper to improve the network performance in mobile ad hoc networks. In the proposed protocol, relay nodes between sender and receiver are used if the sender cannot communicate with the receiver reliably. Furthermore, the receiver may also stop forwarding the received data frame if the frame is received by the next-hop receiver on the route to the final destination node. Simulation results show that the proposed protocol outperforms previous works in terms of increased transmission reliability and reduced delay time. Copyright © 2010 John Wiley & Sons, Ltd.\",\n \"Title: An Adaptive Quorum-Based Energy Conserving Protocol for IEEE 802.11 Ad Hoc Networks\\nYear: 2006\\n\\nAbstract: The lifetime of a mobile ad hoc network (MANET) depends on the durability of the mobile hosts' battery resources. In the IEEE 802.11 Power Saving Mode, a host must wake up at every beacon interval, to check if it should remain awake. Such a scheme fails to adjust a host's sleep duration according to its traffic, thereby reducing its power efficiency. This paper presents new MAC protocols for power saving in a single hop MANET. The essence of these protocols is a quorum-based sleep/wake-up mechanism, which conserves energy by allowing the host to sleep for more than one beacon interval, if few transmissions are involved. The proposed protocols are simple and energy-efficiency. Simulation results showed that our protocols conserved more energy and extended the lifetime of a MANET.\",\n \"Title: An efficient reliable broadcasting protocol for wireless mobile ad hoc networks\\nYear: 2007\\n\\nAbstract: The mobile ad hoc network (MANET) has recently been recognized as an attractive network architecture for wireless communication. Reliable broadcast is an important operation in MANET (e.g., giving orders, searching routes, and notifying important signals). However, using a naive flooding to achieve reliable broadcasting may be very costly, causing a lot of contention, collision, and congestion, to which we refer as the broadcast storm problem. This paper proposes an efficient reliable broadcasting protocol by taking care of the potential broadcast storm problem that could occur in the medium-access level. Existing protocols are either unreliable, or reliable but based on a too costly approach. Our protocol differs from existing protocols by adopting a low-cost broadcast, which does not guarantee reliability, as a basic operation. The reliability is ensured by additional acknowledgement and handshaking. Simulation results do justify the efficiency of the proposed protocol.\",\n \"Title: A distributed Wireless Sensor Network testbed with energy consumption estimation\\nYear: 2010\\n\\nAbstract: In this paper, we design and implement a WSN testbed with a distributed architecture. It allows researchers to submit their experiments and to retrieve the results from the central server. In the testbed, we also propose a software-based hardware-supported scheme to measure the energy consumption of running sensor nodes. And we compare our energy-consumption estimation with oscilloscope measurements. The results show that the energy consumption is very close to oscilloscope measurements.\",\n \"Title: A Multi-Path QoS Routing Protocol in a Wireless Mobile Ad Hoc Network\\nYear: 2001\\n\\nAbstract: mobile ad hoc network (MANET) is one composed of a set of mobile hosts capable of communicating with each other without the assistance of base stations. This paper considers the QoS (quality-of-service) routing problem in a MANET, which is important for many real-time multimedia applications. We propose an on-demand protocol for searching for a multi-path QoS route from a source host to a destination host in a MANET, where a multi-path is a network with a source and a sink satisfying certain bandwidth requirement. Existing works all try to find a uni-path to the destination. The basic idea is to distribute a number of tickets from the source, which can be further partitioned into subtickets to search for a satisfactory multi-path. Through simulations, we justify that the value of our multi-path protocol is in its flexibility: (i) when the network bandwidth is very limited, it can offer a higher success rate to find a satisfactory QoS route than those protocols which try to find a uni-path, and (ii) when the network bandwidth is sufficient, it can perform almost the same as those protocols which try to find a uni-path (in both routing overhead and success rate).\",\n \"Title: Circuit-Switched Broadcasting in Multi-Port Multi-Dimensional Torus Networks\\nYear: 1999\\n\\nAbstract: The one-to-all broadcast is the most primary collective communication pattern in a multicomputer network. This paper studies this problem in a circuit-switched torus with α-port capability, where a node can simultaneously send and receive α messages at one time. This is a generalization of the one-port and all-port models. We show how to efficiently perform broadcast in tori of any dimension, any size, square or nonsquare, using near optimal numbers of steps. The main techniques used are: (i) a “span-by-dimension” approach, which makes our solution scalable to torus dimensions, and (ii) a “squeeze-then-expand” approach, which makes possible solving the difficult cases where tori are non-square. Existing results, as compared to ours, can only solve very restricted sizes or dimensions of tori, or use more numbers of steps.\",\n \"Title: Graph search algorithms and maximum bipartite matching algorithm on the hypercube network model\\nYear: 1990\\n\\nAbstract: In this paper, we propose parallel algorithms for breadth-first search and depth-first search on the hypercube network model. In addition, a parallel algorithm based on the same model for finding maximum matching in bipartite graphs is proposed.\",\n \"Title: Logical Coordinate Assignment For Geographic Routing In Wireless Sensor Networks\\nYear: 2008\\n\\nAbstract: Purpose - The purpose of this paper is to propose a distributed protocol to build a logical coordinate system based on the hop counts of each node to four selected landmarks, and the real location information is not needed.Design/methodology/approach - The designed protocol uses the sink node as one of the landmarks and then selects three other sensor nodes near the corners of the sensor network as landmarks.Findings - The simulation results show that the proposed protocol has the superior performance in packet delivery ratio, average hop counts among nodes, and communication overhead to previous works.Originality/value - This paper presents a distributed protocol to build a logical coordinate system based on hop counts to landmarks.\",\n \"Title: Toward optimal broadcast in a star graph using multiple spanning trees\\nYear: 1997\\n\\nAbstract: In a multicomputer network, sending a packet typically incurs two costs: start-up time and transmission time. This work is motivated by the observation that most broadcast algorithms in the literature for the star graph networks only try to minimize one of the costs. Thus, many algorithms, though claimed to be optimal, are only so when one of the costs is negligible. In this paper, we try to optimize both costs simultaneously for four types of broadcast problems: one-to-all or all-to-all broadcasting in an n-star network with either one-port or all-port communication capability. As opposed to earlier solutions, the main technique used in this paper is to construct from a source node multiple spanning trees, along each of which one partition of the broadcast message is transmitted.\",\n \"Title: A load awareness medium access control protocol for wireless ad hoc network\\nYear: 2003\\n\\nAbstract: A contention-based wireless ad hoc medium access control (MAC) protocol, such as carrier sense multiple access with collision avoidance (CSMA/CA), has the excellence of simple and efficient when the system is light-loaded. The main drawback of such protocols is their inefficiency and unbounded delay when system load is heavy. On the other hand, a contention-free MAC protocol, such as token passing, has better and fair throughput when the system is heavy-loaded. The main drawback of such protocols is their inefficiency when only a small amount of users want to transmit. In this paper, we propose a new load awareness wireless ad hoc MAC protocol (which is called the LA protocol) that exploits the benefits of both contention-based and contention-free protocols. A contention-based MAC protocol is used when system is light-loaded and a contention-free one is used otherwise. Our LA protocol, which operates distributed and is fully compatible with IEEE 802.11 wireless local area network (WLAN) standard, can switch smoothly between the contention-based protocol and the contention-free one. Simulation results show that our protocol indeed extracts the better part of two kinds of protocols and performs well in all systems loads.\",\n \"Title: Intelligent medium access for mobile ad hoc networks with busy tones and power control\\nYear: 1999\\n\\nAbstract: In mobile ad hoc networks (MANETs), one essential issue is how to increase channel utilization while avoiding the hidden-terminal and the exposed-terminal problems. Several MAC protocols, such as RTS/CTS-based and busy-tone-based schemes, have been proposed to alleviate these problems. In this paper, we explore the possibility of combining the concept of power control with the RTS/CTS-based and busy-tone-based protocols to further increase channel utilization. A sender will use an appropriate power level to transmit its packets so as to increase the possibility of channel reuse. The possibility of using discrete, instead of continuous, power levels is also discussed. Through analyses and simulations, we demonstrate the advantage of our new MAC protocol. This, together with the extra benefits such as saving battery energy and reducing cochannel interference, does show a promising direction to enhance the performance of MANETs.\",\n \"Title: A clock synchronization algorithm for multi-hop wireless ad hoc networks\\nYear: 2004\\n\\nAbstract: In multihop wireless ad hoc networks, it is important that all mobile hosts are synchronized. Synchronization is necessary for power management and for frequency hopping spread spectrum (FHSS) operations. IEEE 802.11 standards specify a clock synchronization protocol but this protocol suffers from the scalability problem due to its inefficiency contention mechanism. We propose an automatic self-time-correcting procedure (ASP) to achieve clock synchronization in a multihop environment. Our ASP has two features. Firstly, a faster host has higher priority to send its timing information out than a slower one. Secondly, after collecting enough timing information, a slower host can synchronize to the faster one by self-correcting its timer periodically (which makes it becoming a faster host). Simulation results show that our ASP decreases 60% the average maximum clock drift as compared to the IEEE 802.11 and reduces 99% the number of asynchronism in a large-scale multihop wireless ad hoc networks.\",\n \"Title: A Distributed Localization Scheme for Wireless Sensor Networks with Improved Grid-Scan and Vector-Based Refinement\\nYear: 2008\\n\\nAbstract: Localization is a fundamental and essential issue for wireless sensor networks (WSNs). Existing localization algorithms can be categorized as either range-based or range-free schemes. Range-based schemes are not suitable for WSNs because of their irregularity of radio propagation and their cost of additional devices. In contrast, range-free schemes do not need to use received signal strength to estimate distances and only need simple and cheap hardware, and are thus more suitable for WSNs. However, existing range-free schemes are too costly and not accurate enough or are not scalable. To improve previous work, we present a fully distributed range-free localization scheme for WSNs. We assume that only a few sensor nodes, called anchors, know their locations, and the remaining (normal) nodes need to estimate their own locations by gathering nearby neighboring information. We propose an improved grid-scan algorithm to find the estimated locations of the normal nodes. Furthermore, we derive a vector-based refinement scheme to improve the accuracy of the estimated locations. Analysis, simulation, and experiment results show that our scheme outperforms the other range-free schemes even when the communication radius is irregular.\",\n \"Title: An approximation downlink bandwidth allocation scheme for IEEE 802.16 OFDMA system\\nYear: 2013\\n\\nAbstract: Recently, Orthogonal Frequency Division Multiple Access (OFDMA) transmission technique is applied widely in wireless networks because of its high transmission capacity. The IEEE 802.16 standard has also adopted the OFDMA as its access technique. However, the problem of bandwidth resource allocation in time and frequency is essential for efficient utilization of OFDMA system. In this paper, we proposed an approximation resource allocation scheme to improve the downlink bandwidth utilization. In the resource allocation scheme, we sort the requests of users and allocate bandwidth based on dynamic programming strategy which can save the calculation result of subproblems to reduce the executive time of algorithm. In simulations, it is shown that our scheme outperforms the greedy algorithm in bandwidth utilization. Also, we compare our scheme with optimal allocation method, which is implemented by brute force with branch and bound algorithm. The results show that our method outperforms optimal allocation method by bandwidth utilization, stability, and execution time.\",\n \"Title: Fault-Tolerant Ring Embedding in a Star Graph with Both Link and Node Failures\\nYear: 1997\\n\\nAbstract: The star graph interconnection network has been recognized as an attractive alternative to the hypercube network. Previously, the star graph has been shown to contain a Hamiltonian cycle. In this paper, we consider an injured star graph with some faulty links and nodes. We show that even with fe驴n驴 3 faulty links, a Hamiltonian cycle still can be found in an n-star, and that with fv驴n驴 3 faulty nodes, a ring containing at most 4fv nodes less than that in a Hamiltonian cycle can be found (i.e., the ring contains at least n! 驴 4fv nodes). In general, in an n-star with fe faulty links and fv faulty nodes, where fe + fv驴n驴 3, our embedding is able to establish a ring containing at least n! 驴 4fv nodes.\",\n \"Title: A Distributed Taxi Hailing Protocol in Vehicular Ad-Hoc Networks\\nYear: 2010\\n\\nAbstract: In this paper, a distributed taxi hailing protocol in vehicular ad-hoc networks (VANET) is suggested. Our protocol consists of two parts: taxi booking and taxi de- blocking. Taxi booking part ensures that a vacant taxi with shortest driving distance to passenger under real traffic regulations is booked. Taxi de-blocking part aims to de-block blocked vacant taxis as soon as possible. Simulation results show that compared with previous results, at least 40% of booking time, 50% of waiting time of passengers and 50% of driving distance from booked taxi to passenger, is reduced in our protocol.\",\n \"Title: An Energy Conservation MAC Protocol in Wireless Sensor Networks\\nYear: 2009\\n\\nAbstract: Wireless sensor networks use battery-operated computing and sensing devices. Because of the limitation of battery power in the sensor nodes, energy conservation is a crucial issue in wireless sensor networks. Consequently, there is much literature presenting energy-efficient MAC protocols based on active/sleep duty cycle mechanisms to conserve energy. Convergecast is a common communication pattern across many sensor network applications featuring data gathering from many different source nodes to a single sink node. This leads to high data collision rates, high energy consumption, and low throughput near the sink node. This paper proposes an efficient slot reservation MAC protocol to reduce energy consumption and to make transmission more efficient in data gathering wireless sensor networks. The simulation results show that our protocol provides high throughput, low delivery latency and low energy consumption compared to other methods.\",\n \"Title: Energy-conserving grid routing protocol in mobile ad hoc networks\\nYear: 2003\\n\\nAbstract: The lifetime of a mobile ad hoc network (MANET) depends on the durability of the battery resources of the mobile hosts. Earlier research has proposed several routing protocols specifically for MANET, but most studies have not focused on the limitations of battery resources. The failure of battery resources severely impacts a communications system during natural disasters and in crucial communications environments, such as a battlefield. This study proposes a new energy-aware routing protocol that can increase the durability of the energy resource and, therefore, the lifetime of the mobile hosts and the MANET. The proposed protocol can conserve energy by shortening the idle period of the mobile hosts without increasing the probability of packet loss or reducing routing fidelity. Simulation results indicate that this new energy-conserving protocol can extend the lifetime of a MANET.\",\n \"Title: Virtual landmarks assisted routing protocol in Vehicular Ad hoc Networks\\nYear: 2009\\n\\nAbstract: How to route packets efficiently and reliably is an important issue in Vehicular Ad hoc Networks (VANETs). Due to the high mobility of vehicles, the communication topology of vehicles in VANET changes rapidly. In this paper, a Virtual Landmarks-based approach is suggested. Under the assistant of Virtual Landmarks, an efficient path is guaranteed even if the roads topology is complex. Our approach is applicable to routing packets between a vehicle and static destination. Simulation results shows that in comparison with previous work, our approach has much lowest communication cost and guarantees a reliable path.\",\n \"Title: BlueCube: constructing a hypercube parallel computing and communication environment over Bluetooth radio system\\nYear: 2003\\n\\nAbstract: In existing parallel computing structures, hypercubes have several distinct advantages; they support parallel computing, provide disjoint path and tolerate faults. If devices with computing capabilities can be linked as a hypercube by taking advantage of Bluetooth radio's features, then a high performance computing and efficient communication environment can be established by applying currently used algorithms. This is a pilot study of applying Bluetooth wireless technology to construct a parallel computation and communication environment. A three-stage distributed construction protocol is presented for automatically constructing a hypercube computing environment from Bluetooth devices. The proposed protocol tackles the link construction, role assignment, scatternet formation and network management problems, to construct efficiently a hypercube structure. The proposed protocol enables Bluetooth devices easily to construct a routing path, tolerate faults and create disjoint paths. Parallel and distributed computing will be realized in a Bluetooth wireless environment. Experimental results show the proposed protocol will be able to set up a scatternet that is appropriate for parallel computing and communications\",\n \"Title: A Traffic-Aware Scheduling for Bluetooth Scatternets\\nYear: 2006\\n\\nAbstract: Bluetooth is a low cost, low power, short-range radio technology used for wireless personal area networks (PANs). Bluetooth scatternet is a set of piconets interconnected via bridge devices. Good interpiconet schedulings are necessary for bridge devices to switch among piconets they participate in. This paper proposes an interpiconet scheduling algorithm named \\\"Traffic-Aware Scatternet Scheduling” (TASS), for bridges in Bluetooth scatternets. According to masters' traffic information, TASS can adaptively switch the bridge to high traffic load masters, and increase the usage of the bridge. In addition, TASS can reduce the number of failed \\\"unsniffs” and the overhead of \\\"bridge switch wastes” to further increase overall system performance. Simulation results show that TASS outperforms existing interpiconet scheduling in both network throughput and adaptability for various traffic loads.\",\n \"Title: A cooperative MAC protocol based on 802.11 in wireless Ad hoc networks\\nYear: 2013\\n\\nAbstract: Cooperative communications among nodes is an efficient method to decrease signal fading and interference in MAC layer of wireless Ad hoc networks. However, the previous cooperative MAC protocols are designed for IEEE 802.11b, but not for later standard IEEE 802.11g or 802.11n. To increase performance, improve reliability and reduce energy consumption in communications, we propose a cooperative MAC protocol for IEEE 802.11g and being extended to 802.11n. By partitioning the relays with similar transmission rates into same groups, we can reduce efficiently the time for selecting better relays to help data transmission. Furthermore, we propose a novel retransmission scheme to reduce the retransmission time, while once data transmission is fail, only the relays which have received the data frame will help for retransmission instead of repeating all retransmission cycle. Simulation results show that our proposed protocol outperforms previous work by increasing the throughput and reducing the average delay time in transmission.\",\n \"Title: Tolerating faults in injured hypercubes using maximal fault-free subcube-ring\\nYear: 1997\\n\\nAbstract: In this paper, we present a reconfiguration approach to identify the maximal fault-free subcube-ring for tolerating faults in injured hypercubes. The fault-free subcube-ring is connected by a ring of fault-free subcubes with dilation 3. By exploiting the size of fault-free subcubes as large as possible, the maximal fault-free subcube-ring with higher processor utilization is obtained. Using this approach, we can tolerate more than n faults in n -dimensional hypercubes. To demonstrate the fault-tolerant capability of our approach, we implement two fault-tolerant algorithms, matrix-multiplication and sorting algorithms, on the n CUBE/2E hypercube machine with 32 processors. The simulation results show that our reconfiguration approach has low performance slowdown and high processor utilization.\",\n \"Title: Bubblesort star graphs: a new interconnection network\\nYear: 1996\\n\\nAbstract: In this paper, we propose and analyze a new interconnection network called bubblesort star graph, which is the merger of the bubblesort graph and the star graph. We present the deadlock-free wormhole routing algorithm for the proposed network. We also develop the method to embed a mesh into a bubblesort star graph with dilation two and expansion one. Besides, we use the recursive scheme to embed the multiple disjoint copies of the hypercube into a bubblesort star graph with all faults recovery capacity as well as constant expansion and dilation one or two. This reflects the fact that the embeddability of the bubblesort star graph is much better than that of the star graph.\",\n \"Title: Dynamic channel allocation with location awareness for multi-hop mobile ad hoc networks\\nYear: 2002\\n\\nAbstract: The wireless mobile ad hoc network (MANET) has received a lot of attention recently. This paper considers the channel assignment problem in a MANET which has access to multiple channels. Although a MANET does not have the infrastructure of base stations, interestingly its channel assignment can be conducted efficiently in a way very similar to that in cellular systems (such as GSM). In this paper, we propose a new location-aware channel assignment protocol called GRID-B (read as GRID with Channel Borrowing), which is a sequel of our earlier GRID protocol [Location-aware channel assignment for a multi-channel mobile ad hoc network, Technical Report NCU-HSCCL-2000-02, 2000]. The protocol assigns channels to mobile hosts based on the location information of mobile hosts that might be available from the positioning device (such as GPS) attached to each host. According to our knowledge, no location-aware channel assignment protocol has been proposed before for MANETs. Several channel borrowing strategies are proposed to dynamically assign channels to mobile hosts so as to exploit channel reuse and resolve the unbalance of traffic loads among different areas (such as hot and cold spots). We then propose a multi-channel MAC protocol, which integrates GRID-B. Extensive simulation results are presented to show the advantage of the new GRID-B protocol.\",\n \"Title: An Efficient Transmission Protocol Based on Network Coding in Delay Tolerant Networks\\nYear: 2013\\n\\nAbstract: In Delay Tolerant Networks, the delay of packets is long due to the intermittent connections caused by the mobility of nodes. Epidemic Routing Protocol can reduce the delay time and raise the packet delivery rate by replicating and spread copies of source packets in the networks, but it inevitably exhaust memory resources and network bandwidth. In this paper, we propose a network coding with limited buffer routing protocol. When a buffer of a node is full, two packets in the buffer are chosen randomly and encoded linearly together in to a packet to save buffer space and improve the performance in many-to-one communications.\",\n \"Title: Novel Channel-Hopping Schemes for Cognitive Radio Networks\\nYear: 2014\\n\\nAbstract: Recently, cognitive radio (CR) has become a key technology for addressing spectrum scarcity. In CR networks, spectrum access should not interfere the colocate incumbent networks. Due to the requirement above, common control channel approaches, which are widely used in traditional multichannel environments, may face serious CR long-time blocking problem and control channel saturation problem. Although channel-hopping-based approaches can avoid these two problems, existing works still have significant drawbacks including long time-to-rendezvous, unbalance channel loading, and low channel utilization. In this paper, we introduce three channel-hopping approaches, RCCH, ARCH, and SARCH for synchronous and asynchronous environments, respectively. Compared with previous works, our schemes outperform the state of the art in terms of these metrics.\",\n \"Title: Power control based topology construction for the distributed wireless sensor networks\\nYear: 2007\\n\\nAbstract: Wireless sensor network consists of large number of sensor nodes with limited battery power, which are randomly deployed over certain area for several applications. Due to limited energy resource of sensors, each of them should minimize the energy consumption to prolong the network lifetime. In this paper, a distributed algorithm for the multi-hop wireless sensor network is proposed to construct a novel energy efficient tree topology, without having location information of the nodes. Energy conservation of the nodes is accomplished by controlling transmission power of the nodes. Besides, maintenance of the network topology due to energy scarcity of the gateway nodes is also proposed in the protocol. Simulation results show that our distributed protocol can achieve energy conservation up to an optimum level similar to the centralized algorithm that we have considered and can extend the network lifetime as compared to other distributed algorithms without any power control.\",\n \"Title: Distributed Localization Scheme for Mobile Sensor Networks\\nYear: 2010\\n\\nAbstract: Localization is an essential and important research issue in wireless sensor networks (WSNs). Most localization schemes focus on static sensor networks. However, mobile sensors are required in some applications such that the sensed area can be enlarged. As such, a localization scheme designed for mobile sensor networks is necessary. In this paper, we propose a localization scheme to improve the localization accuracy of previous work. In this proposed scheme, the normal nodes without location information can estimate their own locations by gathering the positions of location-aware nodes (anchor nodes) and the one-hop normal nodes whose locations are estimated from the anchor nodes. In addition, we propose a scheme that predicts the moving direction of sensor nodes to increase localization accuracy. Simulation results show that the localization error in our proposed scheme is lower than the previous schemes in various mobility models and moving speeds.\",\n \"Title: A Distributed Routing Protocol and Handover Schemes in Hybrid Vehicular Ad Hoc Networks\\nYear: 2011\\n\\nAbstract: Vehicular Ad Hoc Networks (VANETs) have received considerable attention in recent years. VANETs provide many services and applications such as Internet access Voice over Internet Protocol (VoIP) and information dissemination. Due to dynamic changes in the network topologies, various routing protocols have been studied in the vehicular environments. However, the communications between source and destination vehicles involve many intermediate vehicles, and due to the high mobility of vehicles, these communication links become disconnected. In this paper, we propose a distributed routing protocol in VANETs with the help of roadside units (RSUs). The proposed scheme includes vehicle registration, finding the location of destination vehicle and the handover maintenance. The simulation results show that our proposed protocol is suitable for vehicles communications in VANETs.\",\n \"Title: A Wireless Human Motion Capturing System for Home Rehabilitation\\nYear: 2009\\n\\nAbstract: Following the trend of miniature intelligent sensing, wearing small, integrated wireless sensor nodes, such as one with accelerometers and compasses, to capture human body motions may have many applications in medical care and computer animation. In this paper, we demonstrate the use of intelligent sensors to capture human motions for home rehabilitation. We design a game to help a patient to conduct his/her rehabilitation program. For each exercise, the patient is instructed to wear sensors on specified movable body parts. The system will then estimate the quality of the movements and give scores as if it is advised by a therapist. In this way, patients will no longer feel painful and boring as that in traditional rehabilitation, which is typically done in hospitals.\",\n \"Title: Toward Optimal Complete Exchange on Wormhole-Routed Tori\\nYear: 1997\\n\\nAbstract: In this paper, we propose new routing schemes to perform all-to-all personalized communication (or known as complete exchange) in wormhole-routed, one-port tori. On tori of equal size along each dimension, our algorithms use both asymptotically optimal startup and transmission time. The results are characterized by several interesting features: 1) the use of gather-scatter tree to achieve optimality in startup time, 2) enforcement of shortest paths in routing messages to achieve optimality in transmission time, 3) application of network-partitioning techniques to reduce the constant associated with the transmission time, and 4) the dimension-by-dimension and gather-scatter-tree approach to make possible applying the results to nonsquare, any-size tori. In the literature, some algorithms are optimal in only one of startup and transmission costs, while some, although asymptotically optimal in both costs, will incur much larger constants associated with the costs. Numerical analysis and experiment both show that significant improvement can be obtained by our scheme on total communication latency over existing results.\",\n \"Title: A Fast Video-on-Demand Broadcasting Scheme for Popular Videos\\nYear: 2004\\n\\nAbstract: Abstract—Broadcasting is a prospective approach to support near video-on-demand services with light communication over- head. By letting clients share channels, such approaches involve partitioning a video into segments and repeatedly broadcasting these segments in multiple channels. An early paper proposed a broadcasting scheme called RFS (recursive frequency splitting), which can significantly reduce clients’ waiting time. While efficient, RFS suffers from a high computational complexity of , where is the number of segments of the video, which is typically very large. This paper proposes an efficient segmentation scheme, which can significantly reduce the compu- tational overhead by slightly sacrificing the number of segments that can be arranged as compared to RFS. Index Terms—Broadcasting, broadband networks, cable TV, video-on-demand.\",\n \"Title: Channel-sharing strategies in two-tier cellular PCS systems\\nYear: 2002\\n\\nAbstract: A two-tier cellular network is characterized by macrocells and microcells overlapping in the service area. This overlapping property provides an advantage that traffic loads can be shared by channels of the two tiers to increase the performance of the system. In this paper, we propose two channel-sharing strategies, namely vertical channel-sharing and vertical-horizontal channel-sharing, to better utilize channels of the network. The call loss probability of new calls and call dropping probability of handoff calls are developed through analyses and simulations. The results justify the advantage of our strategies over existing strategies.\",\n \"Title: Efficient allocation of chain-like task on chain-like network computers\\nYear: 1990\\n\\nAbstract: In this paper, we propose an algorithm to improve Bokhari's method for allocation of chain-like task on chain-like network computers. The time complexity of our algorithm is reduced from the time complexity O(m3n) of Bokhari's to O(min(m,n)m2), where m is the number of modules and n is the number of processors. In addition, our algorithm relaxes Bokhari's constraints of all processors to be utilized and n < m.\",\n \"Title: An On-Demand Bandwidth Reservation QoS Routing Protocol for Mobile Ad Hoc Networks\\nYear: 2006\\n\\nAbstract: QoS routing is the key to support multimedia services in mobile ad hoc networks (MANETs). It is known that resource reservation is one of the best technique to guarantee QoS in MANETs. Lots of the reservation-based QoS routing protocols have been proposed before. However, the effective bandwidth calculation problem and the bandwidth reservation problem have not been addressed seriously. Here, we proposed an on-demand bandwidth reservation QoS routing protocol for TDMA-based multihop MANETs. We propose an algorithm to guide the destination to choose the route that is most likely to satisfy the QoS requirement and an algorithm to reserve the proper time slot and thus keeps more free time slots for other requests. Simulation results show that our protocol can achieve high route establishment probability and low packet loss rate\",\n \"Title: Zooming: A Zoom-Based Approach for Parking Space Availability in VANET\\nYear: 2010\\n\\nAbstract: In this paper, we propose a zoom-based approach for parking space availability. The main idea of our scheme lies on the fact that drivers near the queried locations are interested in detail (zoomed-in) parking space information, while drivers in a distant place are interested in rough (zoomed-out) information about free parking spaces. Our zooming technique is based on discrete cosine transform. Besides, a winner-take-all scheme is also proposed to further reduce communication overhead in packet loss environment. As compared to previous work, simulation results show that our scheme reduces 40% to 50% communication overhead.\",\n \"Title: Route maintenance in a wireless mobile ad hoc network\\nYear: 2000\\n\\nAbstract: A mobile ad-hoc network (MANET) is formed by a cluster of mobile hosts, each installed with a wireless transceiver, without the assistance of base stations. Due to the transmission range constraint of transceivers, two mobile hosts can communicate with each other either directly, if they are close enough, or indirectly, by having other mobile hosts relay their packets. Several routing protocols, such as DSR, SSA, AODV, and ZRP, have been proposed for a MANET with a dynamically changing topology. In a MANET, a route may suddenly become broken because only one host roams away. Even if a route remains connected, it may become worse due to host mobility or a better route newly being formed in the system. Existing protocols, however, will stick with a fixed route between a source-destination pair once it is discovered, until it expires or is broken. In this paper, we show how to enhance several existing protocols with route optimization and local route recovery capability, such that the routing paths can be adjusted on-the-fly while they are still being used for delivering packets or can be patched in minimum wireless bandwidth and packet transmitting delay while route errors occur.\",\n \"Title: Efficient path-based multicast in wormhole-routed mesh networks\\nYear: 2000\\n\\nAbstract: The capability of multidestination wormhole allows a message to be propagated along any valid path in a wormhole-routed network conforming to the underlying base routing scheme. The multicast on the path-based routing model is highly dependent on the spatial locality of destinations participating in multicasting. In this paper, we propose two proximity grouping schemes for efficient multicast in wormhole-routed mesh networks with multidestination capability by exploiting the spatial locality of the destination set. The first grouping scheme, graph-based proximity grouping , is proposed to group the destinations together with locality to construct several disjoint sub-meshes. This is achieved by modeling the proximity grouping problem to graph partitioning problem. The second one, pattern-based proximity grouping , is proposed by the pattern classification schemes to achieve the goal of the proximity grouping. By simulation results, we show the routing performance gains over the traditional Hamiltonian-path routing scheme.\",\n \"Title: Statement-Level Communication-Free Partitioning Techniques for Parallelizing Compilers\\nYear: 1996\\n\\nAbstract: This paper addresses the problem of communication-free partition of iteration spaces and data spaces along hyperplanes. To finding more possible communication-free hyperplane partitions, we treat statements within a loop body as separate schedulable units. Instead of using the information about data dependence distance or direction vectors, our technique explicitly formulates array references as transformations from statement-iteration spaces to data spaces. Based on these transformations, the necessary and sufficient conditions for communication-free partition along hyperplanes to be feasible have been proposed. This approach can be applied to all programs with an imperfectly nested loop or sequences of imperfectly nested loops, whose array references are affine functions of outer loop indices or loop invariant variables. The proposed approach is more practical than existing methods in finding the data and computation distribution patterns that can cause the processor to execute fully-parallel on multicomputers without any interprocessor communication.\",\n \"Title: A Region-Based Hierarchical Location Service with Road-Adapted Grids for Vehicular Networks\\nYear: 2010\\n\\nAbstract: In VANETs, it is very important to communicate between two vehicles, but how to get the correct position of a vehicle is not easy. Due to vehicles are moving fast, topology in VANETs changes rapidly. As a result, location services processed in VANETs are more difficult than in MANETs. In our thesis, we propose a hierarchical location service system, it provides a low cost and rapid service. First, we select the main arteries to divide network into grids because of there are more vehicles than in normal roads, and then design a mechanism that when vehicles need to send update packets. This mechanism can decrease the number of update packets and still gain correct vehicles‟ location. Second, we design grids with three levels, the higher the level, the larger the area. Each level stores update packets sent within its area. Vehicles using our system can find the destination vehicle distributedly within a small area; if the target is not within this area, then find within a larger area. Besides, we propose a packets collection method, it can be adjusted with different size of collection area. The simulation results show that our scheme could decrease the number of location update packets effectively, and keep high success rate of location service.\",\n \"Title: A dynamic channel-borrowing approach with fuzzy logic control in distributed cellular networks\\nYear: 2004\\n\\nAbstract: In this paper, a fuzzy-based dynamic channel-borrowing scheme (FDCBS) is presented to maximize the number of served calls in a distributed wireless cellular network. The uneven traffic load may create hot-spot cells and possibly causes a high blocking rate in hot-spot cells. Most conventional methods use load indices with a threshold value to determine the load status of a cell. However, those exists a ping–pong effect, as loads are around the threshold value. This result causes an unstable system and unnecessary message passing overhead. In addition, the estimation of traffic load is difficult and time-consuming. Thus, an intelligent prediction mechanism is needed. In this paper, we develop a method to predict the cell load and to solve the channel-borrowing problem based on the fuzzy logic control. A new channel-borrowing algorithm with multi-channels borrowing is also presented in this paper. A borrowing mechanism supporting the present facility has been built on the application-level of wireless cellular networks. The FDCBS exhibits better adaptability, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. Through simulations, we evaluate the blocking rate, update overhead, and channel acquisition delay time of the proposed method. The results demonstrate that our algorithm has lower blocking rate, less updated overhead, and shorter channel acquisition delays.\",\n \"Title: Efficient index generation for compiling two-level mappings in data-parallel programs\\nYear: 2000\\n\\nAbstract: This paper presents compilation techniques to compress holes, which are caused by the non-unitalignment stride in a two-level data-processor mapping. Holes are the memory locations mapped byuseless template cells. To fully utilize the memory space, memory holes should be removed. In a twoleveldata-processor mapping, there is a repetitive pattern for array elements mapped onto processors.We classify blocks into classes and use a class table to record the distribution of each class in the...\",\n \"Title: Design and implementation of a navigation system for autonomous mobile robots\\nYear: 2010\\n\\nAbstract: In this paper, a navigation system for autonomous mobile robots is proposed. Our navigation system is a hybrid of behaviour-based and model-based navigation systems. In our system, a behaviour-based subsystem is in charge of low-level reactive actions, and a model-based subsystem is responsible for high-level planned actions. If there are obstacles in the way, the navigation system will use our obstacle avoidance algorithm to navigate around these obstacles and keep the robot moving towards the destination. On the basis of our experimental results, our navigation system can navigate the robot to the destination effectively.\",\n \"Title: A mobile scaffolding-aid-based bird-watching learning system\\nYear: 2002\\n\\nAbstract: In this paper, we develop a mobile scaffolding-aid-based bird-watching learning system, which aims to construct an outdoor mobility-learning activity under the up-to-date wireless technology. The proposed bird-watching learning (BWL) system is designed on the wireless mobile ad-hoc network. In the BWL system, each learner device has PDA (personal digital assistances) with a Wi-Fi (IEEE 802.11b) card, within a WLAN environment. Specially, the BWL system contains a mobile learn sheet sub-system, which integrates the scaffolding-aid learn model into the BWL system. Finally, we conduct a formative evaluation to provide statistical results, which is evaluated for the following two purposes; (1) to explore the possible roles and scaffolding aids that the mobile PDA of the BWL system can play and offer in the bird-watching activities, (2) to investigate if the affective and cognitive learning could be possibly benefited from the mobility, portability, and individualization of the mobile PDA of the BWL system.\",\n \"Title: A Clock Synchronization Algorithm for Multihop Wireless Ad Hoc Networks\\nYear: 2007\\n\\nAbstract: In multihop wireless ad hoc networks, it is important that all mobile hosts are synchronized. Synchronization is necessary for power management and for frequency hopping spread spectrum (FHSS) operations. IEEE 802.11 standards specify a clock synchronization protocol but this protocol suffers from the scalability problem due to its inefficiency contention mechanism. In this paper, we propose an automatic self-time-correcting procedure (ASP) to achieve clock synchronization in a multihop environment. Our ASP has two features. First, a faster host has higher priority to send its timing information out than a slower one. Second, after collecting enough timing information, a slower host can synchronize to the faster one by self-correcting its timer periodically (which makes it becoming a faster host). Simulation results show that our ASP decreases 60% the average maximum clock drift as compared to the IEEE 802.11 and reduces 99% the number of asynchronism in a large-scale multihop wireless ad hoc networks.\",\n \"Title: A distributed protocol for query execution in sensor networks\\nYear: 2005\\n\\nAbstract: The paper proposes an efficient distributed protocol to find a subset of connected sensor nodes to cover the queried region. Each node determines whether to be a sensing node to sense the queried region according to its priority, which is represented by the remaining power or sensing area within the queried region. The proposed protocol can efficiently construct a subset of connected sensing nodes and respond the query request to the sink node. Simulation results show that the proposed protocol is more efficient and has a lower communication overhead than the existing protocol.\",\n \"Title: A mobile butterfly-watching learning system for supporting independent learning\\nYear: 2004\\n\\nAbstract: In this paper, we describe the development of a mobile butterfly-watching learning (BWL) system which supports independent learners by offering a new pattern of outdoor mobile learning (or called as m-learning) activities. The proposed BWL system was designed using a wireless mobile ad-hoc learning environment. In our designed system, each individual learner has a wireless handheld device, which is a PDA (personal digital assistant) with an IEEE 802.11 wireless network card and a small-sized CCD camera. One instructor has a notebook computer with a wi-fi wireless LAN card which serves as the local server. The notebook has a complete butterfly database. All learners' wireless handheld devices and the notebook constitute a mobile ad-hoc learning environment. During the butterfly-watching activity, each learner takes a distinct butterfly picture, and wirelessly transmits the picture to the local server. A content-based butterfly-image retrieval technique is applied to search for the most closely matching butterfly information, which is returned in real time to the learner's wireless handheld device. To illustrate the effect of the BWL system, an outdoor BWL activity was actually performed at elementary school in Taiwan. This article reports on our attempts to develop a new m-learning system to support an independent learning model. We deeply believe that it is worth developing a mobile learning system to provide a possible independent-learning environment for outdoor learners.\",\n \"Title: Efficient address generation for affine subscripts in data-parallel programs\\nYear: 1998\\n\\nAbstract: This paper presents an efficient compilation technique to generate the local memory access sequences for block-cyclically distributed array references with affine subscripts in data-parallel programs. For the memory accesses of an array reference with affine subscript within a two-nested loop, there exist repetitive patterns both at the outer and inner loops. We use tables to record the memory accesses of repetitive patterns. According to these tables, a new start-computation algorithm is proposed to compute the starting elements on a processor for each outer loop iteration. The complexities of the table constructions are O(k+s2), where k is the distribution block size and s2 is the access stride for the inner loop. After tables are constructed, generating each starting element for each outer loop iteration can run in O(1) time. Moreover, we also show that the repetitive iterations for outer loop are Pk/gcd(Pk,s1), where P is the number of processors and s1 is the access stride for the outer loop. Therefore, the total complexity to generate the local memory access sequences for a block-cyclically distributed array with affine subscript in a two-nested loop is O(Pk/gcd/(Pk,s1)+k+s 2)\",\n \"Title: Power management protocol for regular wireless sensor networks\\nYear: 2005\\n\\nAbstract: Most of the existing power saving protocols are designed for irregular networks. These protocols can also be applied to regular networks, but these protocols do not consider the characteristics of regular networks and thus are more complicated and less efficient than the protocols designed for regular networks. Therefore, we propose a novel power management protocol for regular WSNs. Gathering information to the base station is an important operation for WSN. Hence, even some nodes switch to PS mode, the network still needs to be connected so that the sensed information can be sent to the base station through the active nodes. The goal of our protocols is to choose several different connected dominating sets, so that these connected dominating sets can switch to active mode in turn to serve other nodes in PS mode. Simulation results show that our power management protocol can conserve lots of power and greatly extend the lifetime of the WSN with a reasonable extra transmission delay.\",\n \"Title: Fault-tolerant ring embedding in star graphs\\nYear: 1996\\n\\nAbstract: We consider an injured star graph with some faulty links and nodes. We show that even with fe⩽n-3 faulty links a Hamiltonian cycle still can be found in an n-star, and that with fv ⩽n-3 faulty nodes a ring containing at most 4fv nodes less than that in a Hamiltonian cycle can be found (i.e., containing at least n!-4fv nodes). In general, in an n-star with fe faulty links and fv faulty nodes, where f e+fv⩽n-3 our embedding is able to establish a ring containing at least n!-4fv nodes\",\n \"Title: Compiling array references with affine functions for data-rarallel programs\\nYear: 1998\\n\\nAbstract: An important research topic is parallelizing of compilers to generate local memory access sequences and communication sets while compiling a data-parallel language into an SPMD (Single Program Multiple Data) program. In this paper, we present a scheme to efficiently enumerate local memory access sequences and to evaluate communication sets. We use a class table to store information that is extracted from array sections and data distribution patterns. Given array references and data distributions, we can utilize the class table to generate communication sets in closed forms. Furthermore, we derive the algorithms for sending and receiving necessary data between processors. An algorithm for generating the class table is presented, and the time complexity of this algorithm is O(s), where s is the array section stride. The technique of generating communication sets for one index variable has been implemented on a DEC Alpha 3000 workstation. The experimental results confirm the advantage of our scheme, especially when the array section stride is larger than the block size. Finally, we adapt our approach to handle array references with multiple index variables. The time complexity for constructing the whole class table is O(s(2)).\",\n \"Title: A Comment on \\\"Short Channel Hopping Sequence Approach to Rendezvous for Cognitive Networks\\\".\\nYear: 2014\\n\\nAbstract: Recently, Reguera et al. proposed a channel hopping scheme called short-sequence-based (SSB) rendezvous algorithm which works under symmetric and asymmetric channel models. After our revisit of the SSB implementation under the asymmetric model, we found that some cases will fail to have rendezvous in the asynchronous environment and the performance of SSB cannot be guaranteed as one would expect. In addition, we propose a conjecture for the failing cases.\",\n \"Title: Design and implementation of a transmission protection protocol to improve the performance of wireless sensor networks in hybrid networks\\nYear: 2014\\n\\nAbstract: In hybrid networks, the devices of Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) will interfere with each other when working in a same area because they use the same band, 2.4 GHz. With the greater transmission power and more aggressive channel access time resolution, WLANs often affect the communication of WSNs severely. To eliminate this kind of interference effect, we design protection nodes and propose a transmission protection protocol, WSNs Transmission Protection Protocol (WTPP), to improve the transmission performances of WSNs in hybrid networks. The protection nodes can emit protection signal periodically to block the traffic of WLANs and permit the transmission of WSNs. We implement WTPP in a hybrid network testbed to prove its feasibility. Comparing with legacy ZigBee, the experimental results show that WTPP can improve the packet delivery ratio of WSNs efficiently under the interference of WLANs. When WSNs work on low duty cycle, the throughput degradation of WLANs is less than 6%.\",\n \"Title: Interference-aware channel allocation algorithm with game theoretic approach for cognitive radio networks\\nYear: 2014\\n\\nAbstract: In cognitive radio networks, the Secondary Users (SUs) are allowed to utilize unused portions of the licensed spectrum to enhance the performance and efficiency of the channel resource in networks. However, with the increasing number of wireless devices and users competence for the limited channel resource, the channel allocation problem has become an important issue in the cognitive radio networks. Moreover, the interference in communication has become an important factor that affects the efficiency of transmission in cognitive radio networks. In this paper, we proposed an algorithm with game theoretic approach to solve the problem of channel allocations in cognitive radio networks, based on interference aware information between communication pairs. By game theory, the channel allocations of SUs are proposed by their perceived utilities associated with possible actions of neighboring users. The effectiveness of the communication links is determined by the bandwidth of the available channels to the SUs and the heterogeneous interference range between the communication links. Our proposed algorithm can achieve Nash Equilibrium convergence in the game theory.\",\n \"Title: A registration system for aiding in localization and routing in hybrid VANETs\\nYear: 2012\\n\\nAbstract: Hybrid vehicular ad hoc networks (VANETs) allow Inter-Vehicle Communications and Roadside-to-Vehicle Communications. The proposed protocol utilizes the Roadside Units (RSUs) for the implementation of a registration process which allows for the provision of a localization service. The presented RSUs architecture breaks the VANETs into smaller regions managed by a RSU in which individual On Board Units (OBUs) register providing its current position and velocity vectors. Using the data provided by the OBUs, a localization service can be implemented. When the source need to send data, the location of the destination is calculated at the source RSU and the destination RSU using controlled flooding locates the destination vehicle and establishes a route path between source and destination. Simulation results show that it performs well providing good throughput, high packet delivery ration, low delivery delays with very low overhead.\",\n \"Title: A Hole Avoiding Routing Protocol in Wireless Sensor Networks\\nYear: 2014\\n\\nAbstract: In wireless sensor networks, an important challenge often faced in geographic greedy forwarding is the local minimum phenomenon which is caused by holes. For solving this problem, most hole-avoiding protocols route packets along the perimeter of holes or forbidden regions. Thus, sensor nodes on the perimeter of holes and forbidden regions exhaust their energy faster than others, which enlarge the hole size, called growing hole problem. In this paper, we propose an energy-efficient hole avoiding routing protocol (HARP) for growing hole problem in multi-hole environments.\",\n \"Title: Designing efficient parallel algorithms on mech-connected computers with multiple broadcasting\\nYear: 1990\\n\\nAbstract: Semigroup and prefix computations on two-dimensional mesh-connected computers with multiple broadcasting (2-MCCMBs) are studied. Previously, only square 2-MCCMBs with N processing elements were considered for semigroup computations of N data items, andO(N/sup 1/6/) time was required. It is found that square machines are not the best form for semigroup computations, and an O(N/sup 1/8/)-time algorithm is derived on an N/sup 5/8/*N/sup 3/8/ rectangular 2-MCCMB. This time complexity can be further reduced toO(N/sup 1/9/) if fewer processing elements are used. Parallel algorithms for prefix computations with the same time complexities are derived.\",\n \"Title: A new fuzzy linear mapping technique for facial feature extraction and recognition\\nYear: 1996\\n\\nAbstract: Fast feature matching process and high recognition rates are two important issues in face recognition systems. In this paper, a fuzzy neural network based face recognition system which addresses on these two subjects is proposed. This face recognition system uses a fuzzy linear mapping for feature extraction and a fuzzy neural network for fuzzy feature matching. Experimental results show that the proposed face recognition system has two advantages: 1) higher recognition rates are achieved in comparison with statistical feature extraction methods; and 2) feature matching process using fuzzy neural network is faster than minimum distance classifier\",\n \"Title: Wildcard Rules Caching and Cache Replacement Algorithms in Software-Defined Networking.\\nYear: 2016\\n\\nAbstract: In software-defined networking, flow tables of OpenFlow switches are implemented by ternary content addressable memory (TCAM). Although TCAM can process input packets in high speed, it is a scarce and expensive resource providing only a few thousands of rule entries on a network switch. Rules caching is a technique to solve the TCAM capacity problem. However, the rule dependency problem is a chall...\",\n \"Title: Asynchronous Quorum-Based Blind Rendezvous Schemes for Cognitive Radio Networks.\\nYear: 2016\\n\\nAbstract: In cognitive radio networks, unlicensed users [secondary users (SU)] need to rendezvous on licensed channels before establishing communication links. Dedicated common control channel is the simplest way to achieve rendezvous. However, due to the absolute priority of licensed users [primary users (PU)] on accessing licensed channels, a dedicated common control channel may cause the PU long-time blo...\",\n \"Title: A Game Theory Based Congestion Control Protocol for Wireless Personal Area Networks.\\nYear: 2016\\n\\nAbstract: In wireless sensor networks (WSNs), the presence of congestion increases the ratio of packet loss and energy consumption and reduces the network throughput. Particularly, this situation will be more complex in Internet of Things (IoT) environment, which is composed of thousands of heterogeneous nodes. RPL is an IPv6 routing protocol in low power and lossy networks standardized by IETF. However, the RPL can induce problems under network congestion, such as frequently parent changing and throughput degradation. In this paper, we address the congestion problem between parent nodes and child nodes in RPL-enabled networks, which typically consist of low power and resource constraint devices. To mitigate the effect of network congestion, we design a parent-change procedure by game theory strategy, by which the child nodes can change next hop neighbors toward the sink. Comparing to the ContikiRPL implementation, the simulation results show that our protocol can achieve more than two times improvement in throughput and reduce packet loss rate with less increasing of average hop count.\",\n \"Title: A transmission protocol based on network coding in many-to-one delay tolerant networks\\nYear: 2015\\n\\nAbstract: In delay tolerant networks DTNs, the delay of packets is long due to the intermittent connections caused by the mobility of nodes. Epidemic routing protocol ERP can reduce the delay time and raise the packet delivery rate by replicating and spread copies of source packets in the networks, but it inevitably exhaust memory resources and network bandwidth. In this paper, we propose a network coding with limited buffer routing protocol based on two network models, single packet network model and multiple packets network model. When a buffer of a node is full, two packets in the buffer are chosen randomly and encoded linearly together into a packet to save buffer space and improve the performance in many-to-one communications. Moreover, in the transmitting stage of our network coding routing protocol, we proposed two efficient approaches that can enhance the efficiency of information exchange and packets transmission in communications of delay tolerant networks.\",\n \"Title: A Game Theory Based Congestion Control Protocol for Wireless Personal Area Networks\\nYear: 2015\\n\\nAbstract: In Wireless Sensor Networks (WSNs), the presence of congestion can increase the ratio of packet loss, energy consumption and reduce of the network throughput. Especially, this situation will be more complex in Internet of Things (IoT) environments, which is composed of thousands of heterogeneous nodes. In this paper, we address the congestion problem between child and parent nodes in RPL-enabled networks, which typically consist of low power and resource constraint devices. We use game theory strategy to design a parent-change procedure which decides how nodes changing their next hop node toward sink to mitigate the effect of network congestion. Comparing to the Contiki RPL implementation, the simulation results show that our protocol can achieve more than twofold improvement in packet loss rate and throughput with similar average hop count.\",\n \"Title: An efficient routing algorithm based on segment routing in software-defined networking.\\nYear: 2016\\n\\nAbstract: Software-defined networking (SDN) is an emerging architecture that offers advantages over traditional network architecture. Segment routing (SR) defines the path of information through the network via an ordered list of multi-protocol label switching (MPLS) mechanisms on the packet headers at the ingress device, and this system makes SDN routing management more simple and efficient. SR can also solve some scalability issues in SDN. In this paper, we propose a routing algorithm for SDN with SR that can meet the bandwidth requirements of routing requests. Our algorithm considers the balance of traffic load and reduces the extra cost of packet header size in a network. Simulation results show that the performance of our algorithm is better than that of previously developed algorithms in terms of the average network throughput and the average rejection rate of routing requests.\",\n \"Title: Design and analysis of collision free MAC for wireless sensor networks with or without data retransmission.\\nYear: 2017\\n\\nAbstract: In this paper, a new communication mechanism for IEEE 802.15.4 based Wireless Sensor Networks (WSNs) is designed to reduce the collisions and to prevent simultaneous data transmission by the nodes. Analytical models are designed for the uplink traffic in beacon-enabled slotted CSMA/CA with acknowledgements. In order to avoid the collisions and thereby the number of retransmissions, a new medium access control (MAC) protocol is designed. Beside, the current mechanism of IEEE 802.15.4 CSMA/CA is extended to develop the analytical models by including retransmission limits of the nodes with packet collision probability. Taking uplink traffic of the sensors, a Markov chain model is developed to analyze the energy consumption and throughput of the nodes and to study the impact of various network parameters such as the data rate, packet size and node numbers. The proposed models show that the throughput of the system is reduced and energy consumption is increased due to data retransmissions irrespective of the data rates.\",\n \"Title: User satisfaction based resource allocation schemes for multicast in D2D networks.\\nYear: 2017\\n\\nAbstract: The D2D communication has high potential to serve multiple users with high data rate within a proximity in the next generation cellular networks. In this paper, we consider a multicast scenario of D2D users where each user wishes to receive the same multicast data at varying data rates. Based on our best knowledge, finding an optimal solution to satisfy the user request in the said context requires unreasonable time. Therefore, we have proposed approximation algorithms with two objectives (i) maximize the satisfied throughput, (ii) maximize the number of satisfied users when the available resource blocks are limited. The simulation results show that the proposed algorithms offer a worst-case performance guarantee and outperform the other conventional schemes in terms of throughput, satisfied users count, and fairness.\",\n \"Title: A Scalable And Bandwidth-Efficient Multicast Algorithm Based On Segment Routing In Software-Defined Networking\\nYear: 2017\\n\\nAbstract: Software-Defined Networking (SDN) is an emerging architecture and offers advantages over traditional network architecture, while there exist some scalability challenges. In this paper, we propose a multicast routing algorithm for SDN with segment routing to serve the bandwidth requirement of a multicast routing request. Our algorithm considers the balance of traffic load for network resource of link bandwidth and node flow entries both. Simulation results show that the performance of our algorithm is better than previous works in terms of average network throughput and average rejection rate of routing requests. Besides, the results also show that our multicast architecture improve scalability problem of original SDN model in terms of number of flow entries used.\",\n \"Title: Social activeness based relay selection: A game theoretic approach\\nYear: 2017\\n\\nAbstract: D2D cooperative communication is one of the essential requirements of the next generation networks. As human beings carry D2D devices, their emotions also play a prime role in cooperative data exchange. Several earlier works have discussed the various social factors; none has considered the significance of multiple social networks a user can have contact with. In this paper, we leverage the social contacts of a user with various social networks to decide the next hop relay. We take into account the total friends and their contact duration of each social network to determine the relay that has the maximum potential to disperse the information. By considering these social aspects along with the physical parameters, we developed a utility function to model our problem as a relay selection game. We proved our game model as an exact potential game, which has Nash equilibrium. Simulation results show that the proposed method has better throughput when compared to the conventional methods.\",\n \"Title: Probabilistic k-weighted coverage placement in wireless sensor networks.\\nYear: 2017\\n\\nAbstract: In this paper, we study a new problem called probabilistic k-weighted coverage placement, which is a generalization of the Q-coverage placement. Q-coverage placement assumes that the monitored area has uniform coverage requirement: events within the monitored area should be detected with probability Q x 100% (i.e., detected by Q sensors), while probabilistic k-weighted coverage placement assumes that the monitored area has k-degrees of coverage requirement (i.e., k kinds of detection probability): events within distinct region of the monitored area are detected with distinct detection ability, i.e., one of the k kinds of detection probability. Besides, Q-coverage placement requires that the coverage requirement is integer multiple of 100% detection probability, while probabilistic k-weighted coverage placement allows coverage requirement to be non-integer multiple of 100% detection probability. We derive a lower bound on the number of sensors needed to satisfy the coverage requirement of a probabilistic k-weighted monitored area, and introduce a greedy algorithm to solve the problem.\",\n \"Title: Resource Allocation Schemes for Revenue Maximization in Multicast D2D Networks.\\nYear: 2017\\n\\nAbstract: Mobile users' service satisfaction plays a vital role in improving the revenue of telecom companies. When user data demands are uniform, satisfying the user requests is much easier than when demands are diverse. Yet, in a multicast scenario, each user may wish to view the same multicast data at different bit rates based on their own device capacities or resolutions. In this paper, we consider device-to-device (D2D) multicast users who may demand the multicast data at various rates, and in return, they offer different profits (revenue) to the telecom operator. Moreover, users may have different channel qualities from the base station, which will also affect the data rates. We show that satisfying the user requests to maximize the profit becomes NP-hard when the resource blocks are limited, and propose a greedy heuristic and two approximation algorithms to solve this problem. Besides, we consider an alternative objective of maximizing the number of satisfied users and propose a greedy heuristic algorithm for this variant. Our simulation results demonstrate that the proposed algorithms offer higher profit, throughput, and satisfy more users than the other candidate algorithms.\",\n \"Title: Efficient TCAM Rules Distribution Algorithms in Software-Defined Networking.\\nYear: 2018\\n\\nAbstract: In software-defined networking (SDN), network rules are installed in ternary content-addressable memory (TCAM). TCAM is a scarce and expensive resource which is a bottleneck for scaling SDN. Rule distribution is a strategy to solve the TCAM shortage problem, which decomposes a large table stored at network ingress into a number of smaller sub-tables and distributes them across network switches. Ru...\",\n \"Title: Dynamic Spectrum Allocation Algorithms for Industrial Cognitive Radio Networks.\\nYear: 2018\\n\\nAbstract: Irregular spectrum usage and spectrum scarcity in emergency situations is a common problem in industrial wireless networks. To enhance the dynamic spectrum usage, cognitive radio network (CRN) is introduced in various automotive industrial wireless applications named as industrial cognitive radio network (ICRN). However, establishing the control channel by using channel hopping mechanism in ICRN i...\",\n \"Title: A Multi-Radio Rendezvous Algorithm Based on Chinese Remainder Theorem in Heterogeneous Cognitive Radio Networks.\\nYear: 2018\\n\\nAbstract: In cognitive radio networks (CRNs), secondary users can utilize the temporary unused spectrum opportunistically without affecting the quality of services of the licensed users, also called primary users. It is a fundamental operation for a user to rendezvous with another user on the same channel and establish a communication link. Traditional rendezvous algorithms assume homogeneous CRNs and each ...\",\n \"Title: An Enhanced Fast Multi-Radio Rendezvous Algorithm in Heterogeneous Cognitive Radio Networks.\\nYear: 2018\\n\\nAbstract: In this paper, we propose a fast rendezvous algorithm for a heterogeneous cognitive radio network (CRN), where each user might have more than one radio. One of the well-known problems for most multiradio rendezvous algorithms in the literature is that they are not backward compatible to users with only one radio. To tackle this backward compatibility problem, our approach is a hierarchical constru...\",\n \"Title: Improving Memory Traffic by Assembly-Level Exploitation of Reuses for Vector Registers\\nYear: 2000\\n\\nAbstract: In this paper, we propose a compilation scheme to analyze and exploit the implicit reuses of vector register data. According to the reuse analysis, we present a translation strategy that translates the vectorized loops into assembly vector codes with exploitation of vector reuses. Experimental results show that our compilation technique can improve the execution time and traffic between shared memory and vector registers. Techniques discussed here are simple, systematic, and easy to be implemented in the conventional vector compilers or translators to enhance the data locality of vector registers.\",\n \"Title: Performance evaluation of wireless sensor network with hybrid channel access mechanism\\nYear: 2009\\n\\nAbstract: In this paper, a hybrid channel access mechanism is proposed for the wireless sensor network that considers the channel access procedure of IEEE 802.15.4 and combines the binary exponential backoff mechanism of IEEE 802.11 due to packet collision of nodes after successful channel assessment. Taking the backlogged nodes due to collision, an extended linear feedback model is developed and a discrete-time Markov chain model is designed to analyze the successful and failure probabilities of the system model of the wireless sensor network. Besides, an energy consumption model for the one hop wireless sensor network is developed based on our models and hybrid channel access mechanism. Extensive performance analysis are done to study the effect of binary exponential contention window on energy consumption of the nodes and it is verified that our simulation results totally match with the theoretical results for different size of contention windows and node numbers.\",\n \"Title: Wildcard-rule caching and cache replacement algorithms in Software-Defined Networking.\\nYear: 2017\\n\\nAbstract: Ternary Content Addressable Memory (TCAM) capacity problem is an important issue in Software-Defined Networking. Rule caching is an efficient technique to solve the TCAM capacity problem. However, there exists rule dependency problem in wildcard-rule caching technique. In this paper, we utilize cover-set method to solve the rule dependency problem and propose a wildcard-rule caching algorithm to cache rules into TCAM. In addition, we also propose a cache replacement algorithm considering both temporal and spatial localities. According to the simulation results, our wildcard-rule caching algorithm and cache replacement algorithm have better performance than previous works in terms of caching ratio and hit ratio, respectively.\",\n \"Title: Spectrum Allocation with Guaranteed Rendezvous in Asynchronous Cognitive Radio Networks for Internet of Things\\nYear: 2019\\n\\nAbstract: The massive usage of Internet-of-Things (IoT) devices in various smart applications enables spectrum scarcity issues. In order to enhance the dynamic spectrum capability, Cognitive Radio Network (CRN) is considered as a key technology to address the spectrum scarcity problem. However, the establishment of a common communication channel in CRN by considering the unlicensed heterogeneous devices in an asynchronous environment is a challenging problem. In this paper, a novel Asymmetric Asynchronous Channel Hopping (AACH) mechanism is designed, where secondary users have different sets of available channels and can enter into the network without any global clock synchronization. The proposed algorithms can guarantee the rendezvous within a small interval of time with minimum Inter Rendezvous Intervals (IRI). Simulation results show that the designed protocol outperforms over the existing channel hopping algorithms in terms of the degree of rendezvous, Average Time To Rendezvous (ATTR) and throughput.\",\n \"Title: A Quasi-random Algorithm for Anonymous Rendezvous in Heterogeneous Cognitive Radio Networks.\\nYear: 2019\\n\\nAbstract: The multichannel rendezvous problem that asks two secondary users to rendezvous on a common available channel in a cognitive radio network (CRN) has received a lot of attention lately. Most rendezvous algorithms in the literature focused on constructing channel hopping (CH) sequences that guarantee finite maximum time-to-rendezvous (MTTR). However, these algorithms perform rather poorly in terms of the expected time-to-rendezvous (ETTR) even when compared to the simple random algorithm. In this paper, we propose the quasi-random (QR) CH algorithm that has a comparable ETTR to the random algorithm and a comparable MTTR to the best bound in the literature. Our QR algorithm does not require the unique identifier (ID) assumption and it is very simple to implement in the symmetric, asynchronous, and heterogeneous setting with multiple radios. In a CRN with $N$ commonly labelled channels, the MTTR of the QR algorithm is bounded above by $9 M lceil n_1/m_1 rceil cdot lceil n_2/m_2 rceil$ time slots, where $n_1$ (resp. $n_2$) is the number of available channels to user $1$ (resp. 2), $m_1$ (resp. $m_2$) is the number of radios for user $1$ (resp. 2), and $M=lceil lceil log_2 N rceil /4 rceil *5+6$. Such a bound is only slightly larger than the best $O((log log N) frac{n_1 n_2}{m_1 m_2})$ bound in the literature. When each SU has a single radio, the ETTR is bounded above by $frac{n_1 n_2}{G}+9Mn_1n_2 cdot (1-frac{G}{n_1 n_2})^M$, where $G$ is the number of common channels between these two users. By conducting extensive simulations, we show that for both the MTTR and the ETTR, our algorithm is comparable to the simple random algorithm and it outperforms several existing algorithms in the literature.\",\n \"Title: Collaboration Between Social Internet of Things and Mobile Users for Accuracy-Aware Detection\\nYear: 2021\\n\\nAbstract: Social Internet of Things (SIoT) has become an emerging network paradigm, where IoT devices with Artificial Intelligence (AI) and social relations can automatically establish a collaborative group to identify events locally. On the other hand, mobile users can act as ubiquitous and versatile sensors to improve the accuracy of SIoT event detection. In this paper, we explore the SIoT Collaboration with Crowdsourcing (SCC) problem to jointly select SIoT devices and hire users to monitor events and locations with accuracy requirements, while minimizing the total SIoT communication and computation casts and the user hiring cost. We prove that SCC is NP-hard and cannot be approximated by any factor unless P = NP. Then, we propose a new algorithm, Accuracy- and Social-aware SIoT and User Selection (ASSUS), with the idea of Collaborative Tree (CT) and Accuracy Profit (AP), where CT exploits users' social relations to properly choose intermediate SIoTs. Simulation results manifest that ASSUS can effectively reduce more than 50% of the total cost compared with state-of-the-art algorithms.\",\n \"Title: Cooperative Distributed Deep Neural Network Deployment with Edge Computing\\nYear: 2021\\n\\nAbstract: Deep Neural Networks (DNNs) are widely used to analyze the abundance of data collected by massive Internet-of-Thing (IoT) devices. The traditional approaches usually send the data to the cloud and process the DNN inference on the powerful cloud servers but suffer from long network latency. Therefore, edge computing has emerged to reduce network latency by offloading the computation from the cloud to the edge. However, a single resource-constrained edge device is unable to process real-time DNN inference. Thus, we devise a collaborative edge computing system CoopAI to distribute DNN inference over several edge devices with a novel model partition technique to allow the edge devices to prefetch the required data in advance to compute the inference cooperatively in parallel without exchanging data. Subsequently, we present a new optimization problem to minimize the completion time of distributed DNN inference. An innovative algorithm is then proposed to intelligently partition the model into the proper number and sizes of blocks, deploy them on a suitable number of edge devices, and run them in different rounds. The numerical results manifest that our algorithm outperforms the traditional approach by 20%-30% on the completion time.\",\n \"Title: Deep Learning for Ultra-Wideband Indoor Positioning\\nYear: 2021\\n\\nAbstract: In recent years, the Ultra-wideband (UWB) system has been investigated for indoor localization and navigation by academia and industry. However, the UWB localization accuracy deteriorates when the signal propagates under severe non-line-of-sight (NLoS) conditions. We use two deep learning network models, the long short-term memory (LSTM) network and deep neural network (DNN), to analyze five diffe...\",\n \"Title: UAV Deployment and IoT Device Association for Energy-Efficient Data-Gathering in Fixed-Wing Multi-UAV Networks\\nYear: 2021\\n\\nAbstract: This work studies the deployment of multiple fixed-wing unmanned aerial vehicles (UAVs) for data-gathering from ground IoT devices and the corresponding device association policy. Each UAV is assumed to follow a circular flight trajectory above its responsible network area in order to stay afloat. The device association and the UAVs’ trajectory centers and radii are jointly optimized to maximize t...\",\n \"Title: Distributed DRL-based Resource Allocation for Multicast D2D Communications\\nYear: 2021\\n\\nAbstract: Device-to-device (D2D) communication is one of the promising solutions to improve spectrum efficiency and alleviate the mobile traffic explosion. However, interference mitigation and resource allocation in the underlying cellular network is a challenging task. In this paper, we propose a distributed deep reinforcement learning (DRL) based scheme to solve the interference mitigation and resource allocation problem. According to the channel status, each cellular user (CU) and D2D transmitter (D2D TX) will determine the appropriate reused channel and transmit power to maximize the system throughput. We propose a distributed DRL scheme and integrate two hotbooting algorithms into the scheme to improve the system throughput at the early stage of training. Simulation results show that the proposed distributed DRL with hotbooting outperforms the baselines regarding running time, message overhead, and throughput.\",\n \"Title: Reinforcement based Communication Topology Construction for Decentralized Learning with Non-IID Data\\nYear: 2021\\n\\nAbstract: Federated Learning (FL) allows Internet-of-Things (IoT) devices to train a global model collaboratively and circumvent the security issue. However, the current FL framework has three main drawbacks, the huge network overhead, single point of failure, and accuracy degradation in non-independent-and-identically-distributed (non-IID) data distribution. We propose a novel Deep Reinforcement Learning (DRL) based Decentralized Learning (DL) framework, Deep Select, to 1) reduce the network overhead of conventional FL, 2) construct a good communication topology adaptively to mitigate the effect of non-IID data, and 3) accelerate the DL training by balancing the effects of hitting time (HT) and data bias. Moreover, DeepSelect with a subtly-designed DRL agent is reusable with different levels of non-IID data distributions. To the best of our knowledge, this paper is the first one to indicate that proper neighbor selection for exchanging parameters (not raw data) can counterbalance the data bias's effect and improve the DL convergence with non-IID data. The experiment results show that DeepSelect can reduce 18%-51% training rounds than the other heuristics on FashionMNIST and CIFAR-10 with non-IID data distributions.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":145,"string":"145"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13366,"string":"13,366"}}},{"rowIdx":13367,"cells":{"question_id":{"kind":"string","value":"Themistoklis Charalambous"},"question":{"kind":"string","value":"Generate an abstract for the title \"Approximation of Markov processes by lower dimensional processes\" using the following items: 1. Aggregation \n2. Finite-state Markov Process \n3. Total Variation Distance \n4. Entropy Maximization \n5. Iterative Algorithm"},"answer":{"kind":"string","value":"In this paper, we investigate the problem of aggregating a given finite-state Markov process by another process with fewer states. The aggregation utilizes total variation distance as a measure of discriminating the Markov process by the aggregate process, and aims to maximize the entropy of the aggregate process invariant probability, subject to a fidelity described by the total variation distance ball. An iterative algorithm is presented to compute the invariant distribution of the aggregate process, as a function of the invariant distribution of the Markov process. It turns out that the approximation method via aggregation leads to an optimal aggregate process which is a hidden Markov process, and the optimal solution exhibits a water-filling behavior. Finally, the algorithm is applied to specific examples to illustrate the methodology and properties of the approximations."},"correct_answer":{"kind":"string","value":"In this paper, we investigate the problem of aggregating a given finite-state Markov process by another process with fewer states. The aggregation utilizes total variation distance as a measure of discriminating the Markov process by the aggregate process, and aims to maximize the entropy of the aggregate process invariant probability, subject to a fidelity described by the total variation distance ball. An iterative algorithm is presented to compute the invariant distribution of the aggregate process, as a function of the invariant distribution of the Markov process. It turns out that the approximation method via aggregation leads to an optimal aggregate process which is a hidden Markov process, and the optimal solution exhibits a water-filling behavior. Finally, the algorithm is applied to specific examples to illustrate the methodology and properties of the approximations."},"documents":{"kind":"list like","value":["Title: Towards distributed transmission scheduling for wireless ad hoc networks.\nYear: 2012\n\nAbstract: In this paper we study distributed transmission scheduling via power control in wireless ad hoc networks with multiple channels. The target for each node is to manage to be admitted into a channel from the available channels in the network. The aim of this work is twofold: (a) to determine how a wireless node, based on its limited information, will decide which channel to access and (b), to propose a distributed algorithm for each wireless node with which once the channel is chosen a decision is made whether to stay in the channel or not. Here, we propose an algorithm that, if adopted by all the nodes in the network, it converges to a solution that admits most of the wireless nodes in the network, based on limited information only. Simulations in MATLAB justify the good performance of the algorithm.","Title: Buffer-Aided Successive Opportunistic Relaying With Inter-Relay Interference Cancellation\nYear: 2013\n\nAbstract: In this paper we consider a simple cooperative network consisting of a source, a destination and a cluster of decode-and-forward relays characterized by the half-duplex constraint. At each time-slot the source and (possibly) one of the relays transmit a packet to another relay and the destination, respectively. When the source and a relay transmit simultaneously, inter-relay interference is introduced at the receiving relay. In this work, with the aid of buffers at the relays, we mitigate the detrimental effect of inter-relay interference through either interference cancellation or mitigation. More specifically, we propose the min - power opportunistic relaying protocol that minimizes the total energy expenditure per time slot under an inter-relay interference cancellation scheme. The min - power relay-pair selection scheme, apart from minimizing the energy expenditure, also provides better throughput and lower outage probability than existing works in the literature. The performance of the proposed scheme is demonstrated via illustrative examples and simulations in terms of outage probability and average throughput.","Title: Self-adaptive and self-configured CPU resource provisioning for virtualized servers using Kalman filters\nYear: 2009\n\nAbstract: Data center virtualization allows cost-effective server consolidation which can increase system throughput and reduce power consumption. Resource management of virtualized servers is an important and challenging task, especially when dealing with fluctuating workloads and complex multi-tier server applications. Recent results in control theory-based resource management have shown the potential benefits of adjusting allocations to match changing workloads. This paper presents a new resource management scheme that integrates the Kalman filter into feedback controllers to dynamically allocate CPU resources to virtual machines hosting server applications. The novelty of our approach is the use of the Kalman filter-the optimal filtering technique for state estimation in the sum of squares sense-to track the CPU utilizations and update the allocations accordingly. Our basic controllers continuously detect and self-adapt to unforeseen workload intensity changes. Our more advanced controller self-configures itself to any workload condition without any a priori information. Indicatively, it results in within 4.8% of the performance of workload-aware controllers under high intensity workload changes, and performs equally well under medium intensity traffic. In addition, our controllers are enhanced to deal with multi-tier server applications: by using the pair-wise resource coupling between application components, they provide a 3% on average server performance improvement when facing large unexpected workload increases when compared to controllers with no such resource-coupling mechanism. We evaluate our techniques by controlling a 3-tier Rubis benchmark web site deployed on a prototype Xen-virtualized cluster.","Title: A Distributed Power Control and Transmission Rate Allocation Algorithm over Multiple Channels\nYear: 2011\n\nAbstract: In this paper, we consider multiple channels and wireless nodes with multiple transceivers. Each node assigns one transmitter at each available channel. For each assigned transmitter the node decides the power level and data rate of transmission in a distributed fashion, such that certain Quality of Service (QoS) demands for the wireless node are satisfied. More specifically, we investigate the case in which the average SINR over all channels for each communication pair is kept above a certain threshold. A joint distributed power and rate control algorithm for each transmitter is proposed that dynamically adjusts the data rate to meet a target SINR at each channel, and to update the power levels allowing for variable desired SINRs. The algorithm is fully distributed and requires only local interference measurements. The performance of the proposed algorithm is shown through illustrative examples.","Title: Distributed network size estimation and average degree estimation and control in networks isomorphic to directed graphs.\nYear: 2012\n\nAbstract: Many properties of interest in graph structures are based on the nodes' average degree (i.e., the average number of edges incident to/from each node). In this work, we present asynchronous distributed algorithms, based on ratio consensus, that can be used to accurately estimate the number of nodes in a multi-component system whose communication topology is described by a directed graph. In addition, we describe an asynchronous distributed algorithm that allows each node to introduce or terminate links in order to reach a target average degree in the network. Such an approach can be useful in many realistic scenarios; for example, for the introduction and removal of renewable energy resources in a power network, while maintaining an average degree that fulfils some structural and dynamical properties and/or optimises some performance indicators of the network. The effectiveness of the proposed algorithms is demonstrated via illustrative examples.","Title: Neighbor Discovery in Multichannel Wireless Clique Networks: An Epidemic Approach\nYear: 2013\n\nAbstract: We investigate the problem of neighbor discovery in multichannel wireless ad hoc and sensor networks with epidemic information dissemination. Previous works have considered neighbor discovery in a single channel where at most one node can be discovered per time instant. To reduce the effect of collisions observed in single channel solutions, we formulate models for multichannel neighbor discovery and allow for epidemic dissemination of information. As a result, nodes can discover all their neighbors faster, either directly or indirectly by hopping between orthogonal channels and exploring the neighbors in each of them. We show analytically, by simulations, and by experimental evaluations that the expected neighbor discovery time is reduced considerably compared to single channel neighbor discovery solutions.","Title: Medium Access Control Via Contention-Based Distributed Power Control\nYear: 2012\n\nAbstract: A successful distributed power control algorithm requires only local measurements for updating the power level of a transmitting node, so that eventually all transmitters meet their QoS requirements. Nevertheless, the problem arises when the QoS requirements cannot be achieved for all the users in the network. In this paper, a distributed algorithm for wireless ad hoc networks which is contention-based and makes use of a back off mechanism is proposed. This algorithm aims to eliminate overhead communication, improve fairness, allow nodes to operate asynchronously while establishing some performance level. The performance of the algorithm is evaluated via simulations.","Title: Unconditional stability of the Foschini-Miljanic algorithm.\nYear: 2012\n\nAbstract: In this note we prove the unconditional stability of the Foschini–Miljanic algorithm. Our results show that the Foschini–Miljanic algorithm is unconditionally stable (convergent) even in the presence of bounded time-varying communication delays, and in the presence of topology changes. The implication of our results may be important for the design of Code Division Multiple Access (CDMA) based wireless networks.","Title: Stability Analysis and Power Optimization for Energy Harvesting Cooperative Networks.\nYear: 2012\n\nAbstract: In this letter, we investigate the effects of network-layer cooperation in a wireless three-node network with energy-harvesting nodes and bursty data traffic. By modelling energy harvesting in each node as a queue (buffer) that stores the received energy, we study the interaction between data and energy queues when only knowledge of the arrival rates is available. The maximum stable throughput (in...","Title: Buffer-Aided Relay Selection for Cooperative Diversity Systems without Delay Constraints.\nYear: 2012\n\nAbstract: In this paper, we study the relay selection problem for a finite buffer-aided decode-and-forward cooperative wireless network. A relay selection policy that fully exploits the flexibility offered by the buffering ability of the relay nodes in order to maximize the achieved diversity gain is investigated. This new scheme incorporates the instantaneous strength of the wireless links as well as the s...","Title: Lossless Coding with Generalised Criteria\nYear: 2011\n\nAbstract: This paper presents prefix codes which minimize various criteria constructed as a convex combination of maximum codeword length and average codeword length or maximum redundancy and average redundancy, including a convex combination of the average of an exponential function of the codeword length and the average redundancy. This framework encompasses as a special case several criteria previously investigated in the literature, while relations to universal coding is discussed. The coding algorithm derived is parametric resulting in re-adjusting the initial source probabilities via a weighted probability vector according to a merging rule. The level of desirable merging has implication in applications where the maximum codeword length is bounded.","Title: Transmission Scheduling in Wireless Networks with SINR Constraints\nYear: 2009\n\nAbstract: Despite all the work being done so far in scheduling for wireless networks, the transmission scheduling problem with specific constraints is not yet fully understood and explored. In this work, we find the minimum number of time-slots (or channels) required in any given network and the corresponding transmitting powers, such that all communication requests are being processed correctly, while fulfilling specific constraints that comply with the Quality of Service (QoS) requirements for successful transmissions. More specifically, in this paper, we formulate the optimization problem as a Mixed Integer Program (MIP) and solve the mathematical formulation by a Branch-and-Bound algorithm. Our computational study shows that our methodology is capable of solving exactly networks of varying size but can also provide a near optimal heuristic solution for the hardest instances. The results can be used as bounds for the study of distributed algorithms that aim for the optimal scheduling and power assignment without information about the whole network. Numerical examples are provided to illustrate the validity of our proposed methodology.","Title: Average Consensus in the Presence of Delays and Dynamically Changing Directed Graph Topologies\nYear: 2012\n\nAbstract: Classical approaches for asymptotic convergence to the global average in a distributed fashion typically assume timely and reliable exchange of information between neighboring components of a given multi-component system. These assumptions are not necessarily valid in practical settings due to varying delays that might affect transmissions at different times, as well as possible changes in the underlying interconnection topology (e.g., due to component mobility). In this work, we propose protocols to overcome these limitations. We first consider a fixed interconnection topology (captured by a - possibly directed - graph) and propose a discrete-time protocol that can reach asymptotic average consensus in a distributed fashion, despite the presence of arbitrary (but bounded) delays in the communication links. The protocol requires that each component has knowledge of the number of its outgoing links (i.e., the number of components to which it sends information). We subsequently extend the protocol to also handle changes in the underlying interconnection topology and describe a variety of rather loose conditions under which the modified protocol allows the components to reach asymptotic average consensus. The proposed algorithms are illustrated via examples.","Title: Asymptotic Stability and Decay Rates of Homogeneous Positive Systems With Bounded and Unbounded Delays.\nYear: 2014\n\nAbstract: There are several results on the stability of nonlinear positive systems in the presence of time delays. However, most of them assume that the delays are constant. This paper considers time-varying, possibly unbounded, delays and establishes asymptotic stability and bounds the decay rate of a significant class of nonlinear positive systems which includes positive linear systems as a special case. Specifically, we present a necessary and sufficient condition for delay-independent stability of continuous-time positive systems whose vector fields are cooperative and homogeneous. We show that global asymptotic stability of such systems is independent of the magnitude and variation of the time delays. For various classes of time delays, we are able to derive explicit expressions that quantify the decay rates of positive systems. We also provide the corresponding counterparts for discrete-time positive systems whose vector fields are nondecreasing and homogeneous.","Title: Stability and Performance of Continuous-Time Power Control in Wireless Networks.\nYear: 2014\n\nAbstract: This paper develops a comprehensive stability analysis framework for general classes of continuous-time power control algorithms under heterogeneous time-varying delays. Our first set of results establish global asymptotic stability of power control laws involving two-sided scalable interference functions, and include earlier work on standard interference functions as a special case. We then consider contractive interference functions and demonstrate that the associated continuous-time power control laws always have unique fixed points which are exponentially stable, even under bounded heterogeneous time-varying delays. For this class of interference functions, we present explicit bounds on the decay rate that allow us to quantify the impact of delays on the convergence time of the algorithm. When interference functions are linear, we also prove that contractivity is necessary and sufficient for exponential stability of continuous-time power control algorithms with time-varying delays. Finally, numerical simulations illustrate the validity of our theoretical results.","Title: Adaptive Resource Provisioning for Virtualized Servers Using Kalman Filters\nYear: 2014\n\nAbstract: Resource management of virtualized servers in data centers has become a critical task, since it enables cost-effective consolidation of server applications. Resource management is an important and challenging task, especially for multitier applications with unpredictable time-varying workloads. Work in resource management using control theory has shown clear benefits of dynamically adjusting resource allocations to match fluctuating workloads. However, little work has been done toward adaptive controllers for unknown workload types. This work presents a new resource management scheme that incorporates the Kalman filter into feedback controllers to dynamically allocate CPU resources to virtual machines hosting server applications. We present a set of controllers that continuously detect and self-adapt to unforeseen workload changes. Furthermore, our most advanced controller also self-configures itself without any a priori information and with a small 4.8% performance penalty in the case of high-intensity workload changes. In addition, our controllers are enhanced to deal with multitier server applications: by using the pair-wise resource coupling between tiers, they improve server response to large workload increases as compared to controllers with no such resource-coupling mechanism. Our approaches are evaluated and their performance is illustrated on a 3-tier Rubis benchmark website deployed on a prototype Xen-virtualized cluster.","Title: Sub-homogeneous positive monotone systems are insensitive to heterogeneous time-varying delays.\nYear: 2014\n\nAbstract: We show that a sub-homogeneous positive monotone system with bounded heterogeneous time-varying delays is globally asymptotically stable if and only if the corresponding delay-free system is globally asymptotically stable. The proof is based on an extension of a delay-independent stability result for monotone systems under constant delays by Smith to systems with bounded heterogeneous time-varying delays. Under the additional assumption of positivity and sub-homogeneous vector fields, we establish the aforementioned delay insensitivity property and derive a novel test for global asymptotic stability. If the system has a unique equilibrium point in the positive orthant, we prove that our stability test is necessary and sufficient. Specialized to positive linear systems, our results extend and sharpen existing results from the literature.","Title: Modeling Buffer-Aided Relay Selection in Networks With Direct Transmission Capability\nYear: 2015\n\nAbstract: We consider a wireless relay network that consists of a source, half-duplex decode-and-forward buffer-aided relays and a destination. While the majority of previous works on relay selection assume no direct transmission between source and destination in such a setting, we lift this assumption and propose a link selection policy that exploits both the buffering ability and the opportunity for successful reception of a packet directly from the source. The proposed relay selection scheme incorporates the instantaneous strength of the wireless links and adapts the relay selection decision based on the strongest available link. The evolution of the network as a whole is modeled by means of a Markov chain and thus, the outage probability is associated with the steady state of the Markov chain. It is deduced that even if the link between the source and the destination is in principle a very unreliable link, it is always beneficial for the source to multicast a packet to both the relay with the strongest available link and the destination.","Title: On the minimum latency transmission scheduling inwireless networks with power control under SINRconstraints\nYear: 2015\n\nAbstract: AbstractIn order to alleviate interference and contention in a wireless network, we may exploit the existence of multiple orthogonal channels or time slots, thus achieving a substantial improvement in performance. In this paper, we study a joint transmission scheduling and power control problem that arises in wireless networks. The goal is to assign channels ortimeslots and transmitting powers to communication links such that all communication requests are processed correctly, specified quality-of-service requirements are met, and the number of required time slots is minimised. First, we formulate the problem as a mixed-integer linear programming. Then, we show that the problem considered is non-deterministic polynomial-time hard, and subsequently, we propose non-trivial bounding techniques to solve it. Optimisation methods are also discussed, including a column generation approach, specifically designed to find bounds for the transmission scheduling problem. Moreover, we develop optimisation techniques in which the bounding techniques are integrated in order to derive the optimal solution to the problem faster. We close with an extensive computational study, which shows that despite the complexity of the problem, the proposed methodology scales to problems of non-trivial size. Our algorithms can therefore be used for static wireless networks where propagation conditions are almost constant and a centralised agent is available e.g. cellular networks where the base station can act as a centralised agent or wireless mesh networks, and they can also serve as a benchmark for the performance evaluation of heuristic, approximation or distributed algorithms that aim to find near-optimal solutions without information about the whole network. Copyright © 2013 John Wiley & Sons, Ltd.","Title: Hybrid cooperation through full-duplex opportunistic relaying and max-link relay selection with transmit power adaptation\nYear: 2014\n\nAbstract: In this work, we study a cooperative network with multiple full-duplex buffer-aided relays. A hybrid cooperative relaying policy is proposed that employs power adaptation and consists of two alternative schemes: (i) full-duplex transmission through the relay which requires the least total power expenditure and loop interference is mitigated through power adaptation; (ii) buffer-aided max - link selection with power adaptation, when full-duplexity is not feasible. Aiming to reduce the overhead of channel state information (CSI) acquisition and processing, we propose a suboptimal distributed method for relay selection, for which the network performance is not degraded significantly. We show that power adaptation offers reduced overhead of CSI acquisition. Numerical results and comparisons with other state-of-the-art relaying schemes are provided and performance evaluation in terms of throughput, power minimization and switching rate, show the benefits of the proposed hybrid scheme.","Title: Average consensus in the presence of dynamically changing directed topologies and time delays\nYear: 2014\n\nAbstract: We have recently proposed a robustified ratio consensus algorithm which achieves asymptotic convergence to the global average in a distributed fashion in static strongly connected digraphs, despite the possible presence of bounded but otherwise arbitrary delays. In this work, we propose a protocol which reaches asymptotic convergence to the global average in a distributed fashion under possible changes in the underlying interconnection topology (e.g., due to component mobility), as well as time-varying delays that might affect transmissions at different times. More specifically, we extend our previous work to also account for the case where, in addition to arbitrary but bounded delays, we may have time varying communication links. The proposed protocol requires that each component has knowledge of the number of its outgoing links, perhaps with some bounded delay, and that the digraphs formed by the switching communication topologies over a finite time window are jointly strongly connected.","Title: Average Consensus in the Presence of Delays in Directed Graph Topologies\nYear: 2014\n\nAbstract: Classical distributed algorithms for asymptotic average consensus typically assume timely and reliable exchange of information between neighboring components of a given multi-component system. These assumptions are not necessarily valid in practice due to varying delays that might affect computations at different nodes and/or transmissions at different links. In this work, we propose a protocol that overcomes this limitation and, unlike existing consensus protocols in the presence of delays, ensures asymptotic consensus to the exact average, despite the presence of arbitrary (but bounded) delays in the communication links. The protocol requires that each component has knowledge of the number of its out-neighbors (i.e., the number of components to which it can send information) and its proof of correctness relies on the weak convergence of a backward product of column stochastic matrices. The proposed algorithm is demonstrated via illustrative examples.","Title: Precoding decision for full-duplex X-relay channel with Decode-and-Forward\nYear: 2014\n\nAbstract: In this paper, we study a simple X-relay configuration where the shared relay operates in full-duplex (FD) mode. The relay node may have limited spatial degrees of freedom, and as a result, it may not be able to handle both the loop interference and the multiuser interference. Hence, a decision on the precoding scheme is necessitated. It is often the case that the relay does not have the option of real-time switching between different precoding schemes, either due to hardware limitations of the relay or increased complexity of the problem. Hence, we investigate a “static” precoding decision where the relay node decides on its precoding scheme based only on statistical knowledge of the channel conditions. To perform this decision, the behavior of the system is formulated as a Markov chain and the outage probability of the system is derived in a closed-form with the precoding decision as a parameter. The outage probability is minimized by optimally choosing the precoding scheme, using easily verifiable conditions on the statistical knowledge of the channel conditions. Simulations validate the investigated scheme.","Title: Exponential Stability of Homogeneous Positive Systems of Degree One With Time-Varying Delays\nYear: 2013\n\nAbstract: While the asymptotic stability of positive linear systems in the presence of bounded time delays has been thoroughly investigated, the theory for nonlinear positive systems is considerably less well-developed. This technical note presents a set of conditions for establishing delay-independent stability and bounding the decay rate of a significant class of nonlinear positive systems which includes positive linear systems as a special case. Specifically, when the time delays have a known upper bound, we derive necessary and sufficient conditions for exponential stability of: a) continuous-time positive systems whose vector fields are homogeneous and cooperative and b) discrete-time positive systems whose vector fields are homogeneous and order-preserving. We then present explicit expressions that allow us to quantify the impact of delays on the decay rate and show that the best decay rate of positive linear systems that our bounds provide can be found via convex optimization. Finally, we extend the results to general linear systems with time-varying delays.","Title: Extremum Problems With Total Variation Distance and Their Applications\nYear: 2014\n\nAbstract: The aim of this paper is to investigate extremum problems with pay-off being the total variation distance metric defined on the space of probability measures, subject to linear functional constraints on the space of probability measures, and vice-versa; that is, with the roles of total variation metric and linear functional interchanged. Utilizing concepts from signed measures, the extremum probability measures of such problems are obtained in closed form, by identifying the partition of the support set and the mass of these extremum measures on the partition. The results are derived for abstract spaces; specifically, complete separable metric spaces known as Polish spaces, while the high level ideas are also discussed for denumerable spaces endowed with the discrete topology. These extremum problems often arise in many areas, such as, approximating a family of probability distributions by a given probability distribution, maximizing or minimizing entropy subject to total variation distance metric constraints, quantifying uncertainty of probability distributions by total variation distance metric, stochastic minimax control, and in many problems of information, decision theory, and minimax theory.","Title: Optimal Merging Algorithms for Lossless Codes With Generalized Criteria\nYear: 2014\n\nAbstract: This paper presents lossless prefix codes optimized with respect to a payoff criterion consisting of a convex combination of maximum codeword length and average codeword length. The optimal codeword lengths obtained are based on a new coding algorithm, which transforms the initial source probability vector into a new probability vector according to a merging rule. The coding algorithm is equivalent to a partition of the source alphabet into disjoint sets on which a new transformed probability vector is defined as a function of the initial source probability vector and scalar parameter. The payoff criterion considered encompasses a tradeoff between maximum and average codeword length; it is related to a payoff criterion consisting of a convex combination of average codeword length and average of an exponential function of the codeword length, and to an average codeword length payoff criterion subject to a limited length constraint. A special case of the first related payoff is connected to coding problems involving source probability uncertainty and codeword overflow probability, whereas the second related payoff compliments limited length Huffman coding algorithms.","Title: On the stability of the Foschini-Miljanic algorithm with time-delays\nYear: 2008\n\nAbstract: Many of the distributed power control algorithms for wireless networks in the literature ignore the fact that while the algorithms necessitate communication among users, propagation delays exist in the network. This problem is of vital importance, since propagation delays are omnipresent in wireless networks. The Foschini-Miljanic algorithm is provably stable if there are no time-delays in the execution of the algorithm. However, since the interference measurements are fed back to the transmitter by its corresponding receiver, time- delays are inevitably introduced into the system. This work presents a more realistic version of the well known Foschini- Miljanic algorithm for Distributed Power Control since it considers the time-delays introduced to the system due to propagation delays. In both the continuous and discrete time cases we prove global stability of the system in the presence of propagation delays. Our work is focused on power adaptation in an envi- ronment where there exist propagation delays between the communicating pairs. That is, we consider the fact that the interference measurement is not available at the transmitter instantaneously but with some time-delay. This considera- tion is important and reasonable since there are inevitable propagation delays, something that makes the model of the network more realistic. We consider the same distributed power control algorithm as in (2), but we introduce time- delays at the interference measurements of the receiver that are fed back to the transmitter. Within this setting we prove stability for the continuous-time and discrete- time FM algorithm. More specifically, using the multivariate Nyquist criterion (8) and by determining the set in which the spectrum of the multivariate system lies, we prove that both the continuous and discrete time FM algorithms are globally asymptotically stable (GAS) for arbitrarily large delays. These results indicate that the FM algorithm, compared to other power control algorithms (9), is suitable to be used in any network without requiring any bound on time-delays. The rest of this paper is organized as follows. In the next section, the system model along with the necessary preliminary results are presented, while in section III a brief review of the FM algorithm, both continuous and discrete time, is given. In section IV the stability of those algorithms in the presence of time delays is proven. In section V, we continue with illustrative examples of the results presented. Finally, the conclusions are drawn in section VI.","Title: Dynamic programming with total variational distance uncertainty\nYear: 2012\n\nAbstract: The aim of this paper is to address optimality of stochastic control strategies via dynamic programming subject to total variational distance uncertainty on the conditional distribution of the controlled process. Utilizing concepts from signed measures, the maximization of a linear functional on the space of probability measures on abstract spaces is investigated, among those probability measures which are within a total variational distance from a nominal probability measure. The maximizing probability measure is found in closed form. These results are then applied to solve minimax stochastic control with deterministic control strategies, under a Markovian assumption on the conditional distributions of the controlled process. The results include: 1) Optimization subject to total variational distance constraints, 2) new dynamic programming recursions, which involve the oscillator seminorm of the value function.","Title: Asymptotic stability and decay rates of positive linear systems with unbounded delays\nYear: 2013\n\nAbstract: There are several results on the stability analysis of positive linear systems in the presence of constant or time-varying delays. However, most existing results assume that the delays are bounded. This paper studies the stability of discrete-time positive linear systems with unbounded delays. We provide a set of easily verifiable necessary and sufficient conditions for delay-independent stability of positive linear systems subject to a general class of heterogeneous time-varying delays. For two particular classes of unbounded delays, explicit expressions that bound the decay rate of the system are presented. We demonstrate that the best bound on the decay rate that our results can guarantee can be found via convex optimization. Finally, the validity of the results is demonstrated via a numerical example.","Title: Extremum problems with total variation distance\nYear: 2013\n\nAbstract: The aim of this paper is to investigate extremum problems with pay-off the total variational distance metric subject to linear functional constraints both defined on the space of probability measures, as well as related problems. Utilizing concepts from signed measures, the extremum probability measures of such problems are obtained in closed form, by identifying the partition of the support set and the mass of these extremum measures on the partition. The results are derived for abstract spaces, specifically, complete separable metric spaces, while the high level ideas are also discussed for denumerable spaces endowed with the discrete topology.","Title: Opportunistic relay selection for cooperative networks with buffers\nYear: 2012\n\nAbstract: In this paper, a relay selection policy is proposed that fully exploits the flexibility offered by the buffering ability of the relay nodes in order to maximize the achieved diversity gain. The suggested scheme incorporates the instantaneous strength of the wireless links as well as the status of the finite relay buffers and the relay selection decision is based on the strongest available link. Hence the switching occurs dynamically between relay reception and transmission. We show that the proposed relay selection scheme significantly outperforms conventional relay selection policies for all cases and ensures a diversity gain equal to two times the number of relays for large buffer sizes.","Title: A Buffer-aided Successive Opportunistic Relay Selection Scheme with Power Adaptation and Inter-Relay Interference Cancellation for Cooperative Diversity Systems\nYear: 2013\n\nAbstract: In this paper, we present a relay selection scheme which combines the spectral efficiency of successive opportunistic relaying with the robustness of single-link relay selection. More specifically, we propose a scheme that minimizes the total energy expenditure per time slot under an inter-relay interference cancellation scheme. The new relay selection policy is analyzed in terms of outage probability and diversity by modeling the evolution of relay buffers as a Markov Chain. We construct the state transition matrix of the Markov Chain and obtain its stationary distribution, which in turn, yields the outage probability. The proposed scheme outperforms relevant state-of-the-art relay selection schemes in terms of throughput, diversity, energy efficiency and average delay, as demonstrated via representative numerical examples.","Title: Dynamic Programming Subject to Total Variation Distance Ambiguity.\nYear: 2015\n\nAbstract: The aim of this paper is to address optimality of stochastic control strategies via dynamic programming subject to total variation distance ambiguity on the conditional distribution of the controlled process. We formulate the stochastic control problem using minimax theory, in which the control minimizes the payoff while the conditional distribution, from the total variation distance set, maximizes it. First, we investigate the maximization of a linear functional on the space of probability measures on abstract spaces, among those probability measures which are within a total variation distance from a nominal probability measure, and then we give the maximizing probability measure in closed form. Second, we utilize the solution of the maximization to solve minimax stochastic control with deterministic control strategies, under a Markovian and a non-Markovian assumption, on the conditional distributions of the controlled process. The results of this part include (1) minimax optimization subject to total variation distance ambiguity constraint; (2) new dynamic programming recursions, which involve the oscillator seminorm of the value function, in addition to the standard terms; and (3) a new infinite horizon discounted dynamic programming equation, the associated contractive property, and a new policy iteration algorithm. Finally, we provide illustrative examples for both the finite and infinite horizon cases. For the infinite horizon case, we invoke the new policy iteration algorithm to compute the optimal strategies.","Title: Filtering With Fidelity For Time-Varying Gauss-Markov Processes\nYear: 2016\n\nAbstract: In this paper, we revisit the relation between Nonanticipative Rate Distortion (NRD) theory and real-time realizable filtering theory. Specifically, we give the closed form expression for the optimal nonstationary (time-varying) reproduction distribution of the Finite Time Horizon (FTH) Nonanticipative Rate Distortion Function (NRDF) and we establish its connection to real-time realizable filtering theory via a realization scheme utilizing time-varying fully observable multidimensional Gauss-Markov processes. As an application we provide the optimal filter with respect to a mean square error constraint. Unlike classical filtering theory, our filtering approach based on FTH NRDF is performed with waterfilling. We also derive a universal lower bound to the mean square error of any causal estimator to Gaussian processes based on the closed form expression of FTH NRDF. Our theoretical results are demonstrated via an illustrative example.","Title: Fast Information Exchange in Proximity-Based Multichannel Wireless Networks\nYear: 2015\n\nAbstract: This paper considers the problem of distributed neighbor discovery in multi-channel wireless networks. We propose a protocol in which nodes randomly select a channel and decide whether to transmit or listen for neighbor discovery beacons. When nodes transmit, they use epidemic information dissemination to spread knowledge about all the nodes they have discovered so far. Theoretical guarantees on discovery times are complemented by extensive simulations and practical implementations. The evaluations show that multi-channel communication effectively reduces the number of collisions between nodes in the network (especially in dense networks) and that epidemic information dissemination yields both significant speed-ups and increased resilience to packet losses. Finally, we also show that our protocol compares favorably to previously proposed solutions in the literature.","Title: A Survey on Buffer-Aided Relay Selection.\nYear: 2016\n\nAbstract: Relays receive and retransmit signals between one or more sources and one or more destinations. Cooperative relaying is a novel technique for wireless communications that increases throughput and extends the coverage of networks. The task of relay selection serves as a building block to realize cooperative relaying. Recently, relays with buffers have been incorporated into cooperative relaying pro...","Title: A delay-aware hybrid relay selection policy\nYear: 2016\n\nAbstract: In this paper, we propose a novel relay selection policy based on the Hybrid Relay Selection (HRS) relay selection protocol that takes into account the state of the buffers and aims at reducing the average packet delays in the network. The proposed protocol, called the Delay-Aware HRS (DA - HRS) protocol is analyzed by means of Markov Chains and expressions for the outage probability, throughput and delay are derived. The distributed implementation of the protocol is also discussed. The performance of our proposed protocol is demonstrated via extensive simulations and comparisons with the classical HRS.","Title: Location-Aided Pilot Decontamination for Massive MIMO Systems.\nYear: 2016\n\nAbstract: One of the key limitation of massive MIMO systems is pilot contamination, which is defined as the interference during uplink channel estimation due to re-use of the same pilots in surrounding cells. In this paper, we propose a location-based approach to the pilot contamination problem for uplink MIMO systems. Our approach makes use of the approximate locations of mobile devices to provide good estimates of the channel statistics between the mobile devices and their corresponding base stations (BSs). We aim at minimizing the pilot contamination even when the number of BS antennas is not very large, and when multiple users from different cells, or even the same cell, are assigned the same pilot sequence. First, we characterize a desired angular region of the target user at the target BS in which interference is very low or zero, based on the number of BS antennas and the location of the target user. Second, based on this observation, we propose various pilot coordination methods for multi-user multi-cell scenarios to eliminate pilot contamination.","Title: Infinite Horizon Discounted Dynamic Programming Subject To Total Variation Ambiguity On Conditional Distribution\nYear: 2016\n\nAbstract: We analyze the infinite horizon minimax discounted cost Markov Control Model (MCM), for a class of controlled process conditional distributions, which belong to a ball, with respect to total variation distance metric, centered at a known nominal controlled conditional distribution with radius R is an element of [0,2], in which the minimization is over the control strategies and the maximization is over conditional distributions. Through our analysis (i) we derive a new discounted dynamic programming equation, (ii) we show the associated contraction property, and (iii) we develop a new policy iteration algorithm. Finally, the application of the new dynamic programming and the corresponding policy iteration algorithm are shown via an illustrative example.","Title: Totally Asynchronous Distributed Estimation Of Eigenvector Centrality In Digraphs With Application To The Pagerank Problem\nYear: 2016\n\nAbstract: We propose a distributed coordination mechanism which enables nodes in a directed graph to accurately estimate their eigenvector centrality (eigencentrality) even if they update their values at times determined by their own clocks. The clocks need neither be synchronized nor have the same speed. The main idea is to let nodes adjust the weights on outgoing links to compensate for their update speed: the higher the update frequency, the smaller the link weights.Our mechanism is used to develop a distributed algorithm for computing the PageRank vector, commonly used to assign importance to web pages and rank search results. Although several distributed approaches in the literature can deal with asynchronism, they cannot handle the different update speeds that occur when servers have heterogeneous computational capabilities. When existing algorithms are executed using heterogeneous update speeds, they compute incorrect PageRank values. The advantages of our algorithm over existing approaches are verified through illustrative examples.","Title: Robust Linear Quadratic Regulator For Uncertain Systems\nYear: 2016\n\nAbstract: This paper develops a Linear Quadratic Regulator (LQR), which is robust to disturbance variability, by using the total variation distance as a metric. The robust LQR problem is formulated as a minimax optimization problem, resulting in a robust optimal controller which in addition to minimizing the quadratic cost it also minimizes the level of disturbance variability. A procedure for solving the LQR problem is also proposed and an example is presented which clearly illustrates the effectiveness of our developed methodology.","Title: Optimal Scheduling Of Downlink Communication For A Multi-Agent System With A Central Observation Post\nYear: 2018\n\nAbstract: In this letter, we consider a set of agents, which may receive an observation of their state by a central observation post via a shared wireless network. The aim of this letter is to design a scheduling mechanism for the central observation post to decide how to allocate the available communication resources. The problem is tackled in two phases: first, the local controllers are designed so as to stabilize the subsystems for the case of perfect communication and second, the communication schedule is decided with the aim of maximizing the stability of the subsystems. To this end, we formulate an optimization problem which explicitly minimizes the Lyapunov function increase due to communication limitations. We show how the proposed optimization can be expressed in terms of value of information, we prove Lyapunov stability in probability and we test our approach in simulations.","Title: Relay Pair Selection with Source Precoding in Buffer-Aided Successive Opportunistic Relaying.\nYear: 2017\n\nAbstract: We study a cooperative network with a buffer-aided multi-antenna source, multiple half-duplex (HD) buffer-aided relays and a single destination. Such a setup could represent a cellular downlink scenario, in which the source can be a more powerful wireless device with a buffer and multiple antennas, while a set of intermediate less powerful devices are used as relays to reach the destination. The main target is to recover the multiplexing loss of the network by having the source and a relay to simultaneously transmit their information to another relay and the destination, respectively. Successive transmissions in such a cooperative network, however, cause inter-relay interference (IRI). First, by assuming global channel state information (CSI), we show that the detrimental effect of IRI can be alleviated by precoding at the source, mitigating or even fully canceling the interference. A cooperative relaying policy is proposed that employs a joint precoding design and relay-pair selection. Note that both fixed rate and adaptive rate transmissions can be considered. For the case when channel state information is only available at the receiving side (CSIR), we propose a relay selection policy that employs a phase alignment technique to reduce the IRI. The performance of the two proposed relay pair selection policies are evaluated and compared with other state-of-the-art relaying schemes in terms of outage and throughput. The results show that the use of a powerful source can provide considerable performance improvements.","Title: Loco - Link: A Low-Complexity Link Selection Algorithm For Delay Mitigation In Asymmetric Two-Hop Networks\nYear: 2017\n\nAbstract: While buffer-aided relaying improves the diversity of a multi-hop network, its deployment introduces time-delays, thus rendering buffering unreliable for delay-intolerant applications. To alleviate excessive delays, various studies propose delay-aware protocols, but at the expense of reduced diversity, and consequently, increased outage probability. Attempts to maintain the diversity of the system while trying to reduce delays, however, may lead to even higher delays, especially in asymmetric topologies. In this work, we propose a Low-Complexity (LoCo) link selection algorithm, herein called LoCo - Link, that aims at reducing packet delays and enhancing the performance of practical asymmetric two-hop networks. The complexity of LoCo - Link is derived and compared with other state-of-the-art relay selection policies. The performance of the proposed algorithm is evaluated in terms of outage probability, average throughput and average delay, focusing on scenarios with asymmetric links.","Title: Dynamic Cpu Resource Provisioning In Virtualized Servers Using Maximum Correntropy Criterion Kalman Filters\nYear: 2017\n\nAbstract: Virtualized servers have been the key for the efficient deployment of cloud applications. As the application demand increases, it is important to dynamically adjust the CPU allocation of each component in order to save resources for other applications and keep performance high, e.g., the client mean response time (mRT) should be kept below a Quality of Service (QoS) target. In this work, a new form of Kalman filter, called the Maximum Correntropy Criterion Kalman Filter (MCC-KF), has been used in order to predict, and hence, adjust the CPU allocations of each component while the RUBiS auction site workload changes randomly as the number of clients varies. MCC-KF has shown high performance when the noise is non-Gaussian, as it is the case in the CPU usage. Numerical evaluations compare our designed framework with other current state-of-the-art using real-data via the RUBiS benchmark website deployed on a prototype Xen-virtualized cluster.","Title: Incremental 2d Delaunay Triangulation Core Implementation On Fpga For Surface Reconstruction Via High-Level Synthesis\nYear: 2017\n\nAbstract: This paper presents a 2D Delaunay triangulation core for surface reconstruction implemented on a Field Programmable Gate Array (FPGA) chip. The core implementation is derived using high-level synthesis from a C++ description of an incremental 2D Delaunay triangulation algorithm. This description was modified accordingly so that it can be embedded into a FPGA chip using hardware description language. Goal of this work is to increase the execution speed of the algorithm so as to allow for real-time operation. Towards this end, we performed an optimization process using high level synthesis directives which pipeline regions of the code in order to achieve delay optimization. We show preliminary results using standard benchmark models for surface reconstruction, which show the performance of our design.","Title: On The Resource Allocation Problem In Wireless Networked Control Systems\nYear: 2017\n\nAbstract: This paper considers the scheduling problem of a decentralized system where a number of dynamical subsystems with no computational power are scheduled to transmit their measurements via a resource-limited communication network to a remote decision maker who acts as an estimator, controller and scheduler for the subsystems. We propose a new approach for communication resource allocation for a wide class of objective functions, for both coupled and decoupled systems, and for both scheduling observations as well as control commands. This framework facilitates scheduling over a finite horizon and can explicitly deal with stochastic channels. For decoupled subsystems, we propose the notion of cost of information loss (CoIL) and we demonstrate that the communications resource allocation problem can be directly expressed in terms of CoIL functions as an assignment-type optimization problem. Illustrative examples demonstrate how communication resources affect the performance of the system.","Title: Location-Aided Pilot Contamination Avoidance for Massive MIMO Systems.\nYear: 2018\n\nAbstract: Pilot contamination, defined as the interference during the channel estimation process due to reusing the same pilot sequences in neighboring cells, can severely degrade the performance of massive multiple-input multiple-output systems. In this paper, we propose a location-based approach to mitigating the pilot contamination problem for uplink multiple-input multiple-output systems. Our approach m...","Title: Distributed Averaging andBalancing in Network Systems: with Applications to Coordination and Control\nYear: 2018\n\nAbstract: AbstractRapid developments in digital system and networking technologieshave led to the emergence of complex systems that are defacto managed and controlled over cyber infrastructures, such aswireless and wired broadband networks. The emergence of thistype of network systems, which range from smart grids and trafficnetworks of various sorts, to embedded electronic devices androbotic networks, has sparked huge interest in distributed controlproblems. This is due to the need to properly coordinate the informationexchange between sensors, actuators, and controllersin order to enforce a desirable behavior, without relying on acentralized decision maker. In this monograph, we present somerecent progress in this area by focusing on the key operations ofdistributed average consensus and weight/flow balancing under avariety of communication topologies and adversarial network conditions,e.g., delays, and packet drops. These operations are key incontrol, coordination, and optimization tasks in many emergingapplications; two of these, which we discuss in detail, are thecoordination of distributed energy resources, and the computationof PageRank values.","Title: Channel Prediction With Location Uncertainty for Ad Hoc Networks.\nYear: 2018\n\nAbstract: Multiagent systems (MAS) rely on positioning technologies to determine their physical location, and on wireless communication technologies to exchange information. Both positioning and communication are affected by uncertainties, which should be accounted for. This paper considers an agent placement problem to optimize end-to-end communication quality in a MAS in the presence of uncertainties. Usi...","Title: Power Adaptation In Buffer-Aided Full-Duplex Relay Networks With Statistical Csi\nYear: 2018\n\nAbstract: In networks with multiple wireless nodes and especially in fast changing environments, the continuous acquisition of channel state information (CSI) may become infeasible. In this correspondence paper, we study the relay selection problem for a cooperative network, where full-duplex relays are equipped with buffers and only statistical CSI is available at the transmitters (CSIT). For this setting, a novel relay selection algorithm is proposed, named HyQoS, relying only on statistical CSIT and performing power adaptation. HyQoS solves an optimization problem for selecting the optimal set of relays. We consider two optimization approaches, first, minimization of the total power consumed in the network, and, second, maximization of the throughput per energy unit, while guaranteeing a specific quality of service, in terms of successful transmission probability. The power allocation problem is formulated as a nonlinear optimization one, taking into account inter-relay interference and residual loop interference. Numerical results show that HyQoS can reduce the power expenditure and increase the throughput, by using only statistical CSIT.","Title: Low-Complexity Buffer-Aided Link Selection With Outdated CSI and Feedback Errors.\nYear: 2018\n\nAbstract: Buffer-aided relays can improve the diversity of multi-hop networks, however, they increase packet delays. Thus, various delay-aware protocols have been developed, but without considering the transmission diversity. Moreover, most works adopt ideal assumptions, such as symmetric links, perfect channel state information (CSI), and error-free feedback channels. So, we propose a low-complexity (LoCo)...","Title: Robust Dynamic CPU Resource Provisioning in Virtualized Servers\nYear: 2018\n\nAbstract: We present robust dynamic resource allocation mechanisms to allocate application resources meeting Service Level Objectives (SLOs) agreed between cloud providers and customers. In fact, two filter-based robust controllers, i.e., $\\mathcal {H}_{\\infty }$<mml:mi math...","Title: When To Stop Iterating In Digraphs Of Unknown Size? An Application To Finite-Time Average Consensus\nYear: 2018\n\nAbstract: In multi-agent systems, existing distributed algorithms for finite-time average consensus allow the agents to calculate the exact average in finite time, but typically require the agents to continue the iterative process indefinitely. The problem is that it is impossible for one agent to be certain that all other agents have also computed the average (at least not without a priori bounds on the network size or diameter). In this paper, we enhance an existing finite-time distributed algorithm with a distributed termination mechanism that allows the nodes to agree on terminating their iterations when they have all computed the exact average. This is accomplished by exploiting the fact that the distributed algorithm allows each node to compute, in a finite number of steps, an upper bound of its eccentricity in the network. The proposed distributed termination mechanism also facilitates the computation, in a finite number of steps, of an upper bound on the diameter of the network, which can be used by several algorithms that require such global information. Illustrative examples demonstrate the validity and performance of the proposed algorithm.","Title: Towards A Robust Traffic Admission Control In Homogeneous Urban Vehicular Networks Under Qos Constraints\nYear: 2018\n\nAbstract: In this paper, we consider the problem of controlling the input flow to a homogeneous urban vehicular network such that certain Quality of Service (QoS) constraints are preserved. In such a network, we model the system with two types of queues: external and internal. External queues represent vehicles waiting to enter the urban vehicular network under control, and the internal queue is used to describe the network's aggregated behavior based on the Network Fundamental Diagram (NFD). While most of the works assume perfect knowledge of the NFD describing the urban vehicular network, in reality we can only approximate it. On these grounds, by taking a model of the NFD with uncertainties, we propose a robust control design approach in order to gate input flow to a protected urban vehicular network such that travel time Quality of Service (QoS) constraints are preserved within the network. The proposed controller is compared via simulations with controllers assuming perfect knowledge of the NFD and it is shown that it can provide a larger stability region.","Title: Impact Of Communication Frequency On Remote Control Of Automated Vehicles\nYear: 2018\n\nAbstract: This paper investigates the impact of the communication frequency on the remote control of automated vehicles. In particular, we consider a remote controller, which receives vehicles' state information and issues control commands based on a model predictive control (MPC) framework, to steer the vehicles to reach their respective target position intervals at given specific times. We present a framework where both state information (from the vehicles to the controller) and control actions (from the controller to the vehicles) are communicated through a wireless network. Due to limited communication resources and possible channel impairments, information is not necessarily always provided to the destination (either the controller or the vehicles). Herein, we particularly focus on the communications to the controller and investigate the effect of frequency and last instant of communication. Our results quantify the impact of these factors on the system performance, and subsequently, underline the need for an efficient resource allocation scheme.","Title: Asymptotic Reverse-Waterfilling Characterization of Nonanticipative Rate Distortion Function of Vector-Valued Gauss-Markov Processes with MSE Distortion\nYear: 2018\n\nAbstract: We analyze the asymptotic nonanticipative rate distortion function (NRDF) of vector-valued Gauss-Markov processes subject to a mean-squared error (MSE) distortion function. We derive a parametric characterization in terms of a reverse-waterfilling algorithm, that requires the solution of a matrix Riccati algebraic equation (RAE). Further, we develop an algorithm reminiscent of the classical reverse-waterfilling algorithm that provides an upper bound to the optimal solution of the reverse-waterfilling optimization problem, and under certain cases, it operates at the NRDF. Moreover, using the characterization of the reverse-waterfilling algorithm, we derive the analytical solution of the NRDF, for a simple two-dimensional parallel Gauss-Markov process. The efficacy of our proposed algorithm is demonstrated via an example.","Title: Laplacian-Based Matrix Design For Finite-Time Average Consensus In Digraphs\nYear: 2018\n\nAbstract: In this paper, we consider the problem of assigning time-varying weights on the links of a time-invariant digraph, such that average consensus is reached in a finite number of steps. More specifically, we derive a finite set of weight matrices that are based on the Laplacian and the Laplacian eigenvalues of the given digraph, such that the product of these weight matrices (in any order) leads to a rank-one matrix. Using the weights associated with this sequence of weight matrices, the nodes run two linear iterations (each with its own initial conditions) and, after a finite number of steps, can calculate the average of the initial values by taking the ratio of the two values they possess at the end of the iteration process. As in the case of undirected graphs, we show that the set of matrices depends on the number of nonzero distinct eigenvalues of the Laplacian matrix. However, unlike the case for undirected graphs, the Laplacian matrix is no longer symmetric, and the number of steps depends not only on the number of distinct eigenvalues but also on their algebraic multiplicities. Illustrative examples demonstrate the validity of the derived results.","Title: Optimal Estimation via Nonanticipative Rate Distortion Function and Applications to Time-Varying Gauss--Markov Processes\nYear: 2018\n\nAbstract: In this paper, we develop finite-time horizon causal filters for general processes taking values in Polish spaces using the nonanticipative rate distortion function (NRDF). Subsequently, we apply the NRDF to design optimal filters for time-varying vector-valued Gauss-Markov processes, subject to a mean-squared error (MSE) distortion. Unlike the classical Kalman filter design, the developed filters based on the NRDF are characterized parametrically by a dynamic reverse-waterfilling optimization problem obtained via Karush-Kuhn-Tucker conditions. We develop algorithms that provide, in general, tight upper bounds to the optimal solution to the dynamic reverse-waterfilling optimization problem subject to a total and per-letter MSE distortion constraint. Under certain conditions, these algorithms produce the optimal solutions. Further, we establish a universal lower bound on the total and per-letter MSE of any estimator of a Gaussian random process. Our theoretical framework is demonstrated via simple examples.","Title: A Timer-Based Distributed Channel Access Mechanism in Networked Control Systems.\nYear: 2018\n\nAbstract: We consider a system consisting of multiple heterogeneous control subsystems sharing a common communication resource for accomplishing their control tasks. Despite the numerous advantages that such networked control systems (NCSs) offer, their implementation is limited in practice due to the limited communication resources. We propose a novel distributed approach for the resource allocation proble...","Title: Relay-pair selection in buffer-aided successive opportunistic relaying using a multi-antenna source\nYear: 2019\n\nAbstract: We study a cooperative network with a buffer-aided multi-antenna source, multiple half-duplex (HD) buffer-aided relays and a single destination. Such a setup could represent a cellular downlink scenario, in which the source can be a more powerful wireless device with a buffer and multiple antennas, while a set of intermediate less powerful devices are used as relays to reach the destination. The main target is to recover the multiplexing loss of the network by having the source and a relay to simultaneously transmit their information to another relay and the destination, respectively. Successive transmissions in such a cooperative network, however, cause inter-relay interference (IRI). First, by assuming global channel state information (CSI), we show that the detrimental effect of IRI can be alleviated by precoding at the source, mitigating or even fully cancelling the interference. A cooperative relaying policy is proposed that employs a joint precoding design and relay-pair selection. Note that both fixed rate and adaptive rate transmissions can be considered. For the case when channel state information is only available at the receiver side (CSIR), we propose a relay selection policy that employs a phase alignment technique to reduce the IRI. The performance of the two proposed relay pair selection policies are evaluated and compared with other state-of-the-art relaying schemes in terms of outage and throughput. The results show that the use of a powerful source can provide considerable performance improvements.","Title: Power Allocation for Type-I ARQ Two-Hop Cooperative Networks for Ultra-Reliable Communication.\nYear: 2019\n\nAbstract: We analyze the performance of amplify-and-forward (AF) automatic repeat request (ARQ) for a two-hop cooperative system with reliability constrains. For this setup, we first derive the closed-form outage probability expression. Next, we present a power allocation scheme that allows us to achieve a target outage probability, while minimizing the outage-weighted average power expenditure for asymmetric power allocation between the source and relay. This is cast as an optimization problem, and the optimal power allocation (OPA) is obtained in closed form by invoking the Karush-Kuhn-Tucker (KKT) conditions. We evaluate numerically the OPA strategy between different AF-ARQ transmission rounds and we show that the proposed scheme provides large power gains with respect to the optimized point-to-point ARQ scheme, as well as with respect to the equal power allocation (EPA) strategy.","Title: Hybrid NOMA/OMA with Buffer-Aided Relay Selection in Cooperative Networks\nYear: 2019\n\nAbstract: Non-orthogonal multiple access (NOMA) aims to increase the spectral efficiency of fifth generation networks by relaxing the orthogonal use of radio-resources. In this paper, a network with multiple half-duplex buffer-aided (BA) relays is considered, where the source transmits with a fixed rate toward two users. The users might demand the same rate by the source (e.g., two cellular users requiring ...","Title: Bandit-Based Power Control in Full-Duplex Cooperative Relay Networks\nYear: 2021\n\nAbstract: Full-duplex relaying is an enabling technique of sixth generation (6G) mobile networks, promising tremendous rate and spectral efficiency gains. In order to improve the performance of full-duplex communications, power control is a viable way of avoiding excessive loop interference at the relay. Unfortunately, power control requires channel state information of both source-relay and relay-destination channels, as well as of the loop interference channel, thus resulting in increased overheads. Aiming to offer a low-complexity alternative for power control in full-duplex relay networks, we adopt reward-based learning in the sense of multi-armed bandits. More specifically, we provide bandit-based power control algorithms, relying on acknowledgements/negative-acknowledgements observations by the relay. The proposed algorithms avoid the need for channel state information acquisition and exchange, and can be employed in a distributed manner. Performance evaluation results in terms of outage probability, average throughput and accumulated regret over time highlight an interesting performance-complexity trade-off compared to optimal power control with full channel knowledge and significant performance gains over the cases without power control and random power level selection.","Title: Distributed Detection and Mitigation of Biasing Attacks Over Multi-Agent Networks\nYear: 2021\n\nAbstract: This paper proposes a distributed attack detection and mitigation technique based on distributed estimation over a multi-agent network, where the agents take partial system measurements susceptible to (possible) biasing attacks. In particular, we assume that the system is not locally observable via the measurements in the direct neighborhood of any agent. First, for performance analysis in the att...","Title: Observer-based Control for Vehicle Platooning with a Leader of Varying Velocity\nYear: 2021\n\nAbstract: This paper studies the internal stability and string stability of a vehicle platooning with a varying-velocity leader using a multiple-predecessor following strategy via vehicle-to-vehicle communication. Unlike the common case in which the leader’s velocity is constant and different kinds of PID controllers are implemented, in this case, the fact that the leader has a velocity that varies over tim...","Title: A Priority-Based Distributed Channel Access Mechanism for Control over CAN-like Networks\nYear: 2021\n\nAbstract: In this work, we study the distributed channel access problem for multiple subsystems equipped with smart sensors sharing a capacity-limited communication network to perform their control tasks. We propose a fully distributed scheme to use the limited communication resources efficiently with respect to a quadratic cost which reflects the control performance. More specifically, we adopt a priority ...","Title: A Survey on Reinforcement Learning-Aided Caching in Heterogeneous Mobile Edge Networks\nYear: 2022\n\nAbstract: Mobile networks experience a tremendous increase in data volume and user density due to the massive number of coexisting users and devices. An efficient technique to alleviate this issue is to bring the data closer to the users by exploiting cache-aided edge nodes, such as fixed and mobile access points, and even user devices. Meanwhile, the fusion of machine learning and wireless networks offers new opportunities for network optimization when traditional optimization approaches fail or incur high complexity. Among the various machine learning categories, reinforcement learning provides autonomous operation without relying on large sets of historical data for training. In this survey, reinforcement learning-aided mobile edge caching solutions are presented and classified, based on the networking architecture and optimization target. As sixth generation (6G) networks will be characterized by high heterogeneity, fixed cellular, fog, cooperative, vehicular, and aerial networks are studied. The discussion of these works reveals that there exist reinforcement learning-aided caching schemes with varying complexity that can surpass the performance of conventional policy-based approaches. Finally, several open issues are presented, stimulating further interest in this important research field.","Title: Complete Characterization of Gorbunov and Pinsker Nonanticipatory Epsilon Entropy of Multivariate Gaussian Sources: Structural Properties\nYear: 2022\n\nAbstract: This paper derives the optimal test channel distribution and the complete characterization of the classical Gorbunov and Pinsker (1973), Gorbunov and Pinsker (1974) nonanticipatory epsilon entropy of multivariate Gaussian Markov sources with square-error fidelity, which remained an open problem since 1974. The paper also formulates a state dependent nonanticipatory epsilon entropy, in which past r...","Title: Consensus-Based Distributed Estimation in the Presence of Heterogeneous, Time-Invariant Delays\nYear: 2022\n\nAbstract: Classical distributed estimation scenarios typically assume timely and reliable exchanges of information over the sensor network. This letter, in contrast, considers single time-scale distributed estimation via a sensor network subject to transmission time-delays. The proposed discrete-time networked estimator consists of two steps: (i) consensus on (delayed) a-priori estimates, and (ii) measurement update. The sensors only share their a-priori estimates with their out-neighbors over (possibly) time-delayed transmission links. The delays are assumed to be fixed over time, heterogeneous, and known. We assume distributed observability instead of local observability, which significantly reduces the communication/sensing loads on sensors. Using the notions of augmented matrices and the Kronecker product, the convergence of the proposed estimator over strongly-connected networks is proved for a specific upper-bound on the time-delay.","Title: Distributed Alternating Direction Method of Multipliers using Finite-Time Exact Ratio Consensus in Digraphs\nYear: 2021\n\nAbstract: In this work, we consider the distributed optimization problem in which each node has its own convex cost function and can communicate directly only with its neighbors, as determined by a directed communication topology (directed graph or digraph). First, we reformulate the optimization problem so that Alternating Direction Method of Multipliers (ADMM) can be utilized. Then, we propose an algorithm, herein called Distributed Alternating Direction Method of Multipliers using Finite-Time Exact Ratio Consensus (D-ADMM-FTERC), to solve the multi-node convex optimization problem, in which every node performs iterative computations and exchanges information with its neighbors. At every iteration of D-ADMM-FTERC, each node solves a local convex optimization problem for the one of the primal variables and utilizes a finite-time exact consensus protocol to obtain the optimal value of the other variable, since the cost function for the second primal variable is not decomposable. If the individual cost functions are convex and not-necessarily differentiable, the proposed algorithm converges at a rate of O(1/k), where k is the iteration counter. The efficacy of D-ADMM-FTERC is demonstrated via a distributed least square optimization example. Additionally, comparisons with other state-of-the-art algorithms are provided on both small and large scale systems showing the superior precision and time-efficient performance of D-ADMM-FTERC.","Title: Bandit-Based Power Control in Full-Duplex Cooperative Relay Networks With Strict-Sense Stationary and Non-Stationary Wireless Communication Channels\nYear: 2022\n\nAbstract: Full-duplex relaying is an enabling technique of sixth generation (6G) mobile networks, promising tremendous rate and spectral efficiency gains. In order to improve the performance of full-duplex communications, power control is a viable way of avoiding excessive loop interference at the relay. Unfortunately, power control requires channel state information of source-relay, relay-destination and loop interference channels, thus resulting in increased overheads. Aiming to offer a low-complexity alternative for power control in such networks, we adopt reward-based learning in the sense of multi-armed bandits. More specifically, we present bandit-based power control, relying on acknowledgements/negative-acknowledgements observations by the relay. Our distributed algorithms avoid channel state information acquisition and exchange, and can alleviate the impact of outdated channel state information. Two cases are examined regarding the channel statistics of the wireless network, namely, strict-sense stationary and non-stationary channels. For the latter, a sliding window approach is adopted to further improve the performance. Performance evaluation highlights a performance-complexity trade-off, compared to optimal power control with full channel knowledge and significant gains over cases considering channel estimation and feedback overheads, outdated channel knowledge, no power control and random power level selection. Finally, it is shown that the sliding-window bandit-based algorithm provides improved performance in non-stationary settings by efficiently adapting to abrupt changes of the wireless channels.","Title: Information freshness and packet drop rate interplay in a two-user multi-access channel\nYear: 2022\n\nAbstract: In this work, we combine the two notions of timely delivery of information to study their interplay; namely, deadline-constrained packet delivery due to latency constraints and freshness of information. More specifically, we consider a two-user multiple access setup with random access, in which user 1 is a wireless device with a buffer and has external bursty traffic which is deadline-constrained, while user 2 monitors a sensor and transmits status updates to the destination. We provide analytical expressions for the throughput and drop probability of user 1. For user 2, we derive in closed form the age of information distribution, the average age of information (AoI), and the probability the AoI to be larger than a certain value for each time slot. The relations reveal a trade-off between the average AoI of user 2 and the drop rate of user 1: the lower the average AoI, the higher the drop rate, and vice versa. Simulations corroborate the validity of our theoretical results.","Title: Finite-Time and Adaptive Observer based Fully Distributed Synchronization of Heterogeneous Linear Systems with Delays\nYear: 2022\n\nAbstract: In this paper, the output synchronization (OS) problem of heterogeneous linear multi-agent systems (MASs) with input delays is addressed. Agents may have different state dimensions and different dynamics. A finite-time observer (FO) is firstly proposed to estimate the uncertain leader's system dynamics. Then, based on the above FO, an adaptive observer (AO) is designed to estimate leader's state information. Thirdly, a novel state predictor is proposed to tackle the input delay effect based on the above AO and output regulation theory. After that, a third observer is designed to estimate the above state predictor so that the controller can be implemented in reality. The stability analysis is performed via Lyapunov stability theory with sufficient conditions derived in terms of an algebraic Riccati equation. The main achievement of this work is the construction of an observer-based fully distributed controller (FDC) which relies on local information only and does not require knowledge of the leader's dynamics or global graph information. As a result, such an approach can be implemented to large-scale systems. Finally, the effectiveness of the proposed FDC is verified via simulations and the influence of the system's graph structure on the convergence rate of the FDC is discussed.","Title: Towards Establishing String Stability Conditions For Heterogeneous Vehicle Platoons Under the MPF Topology\nYear: 2022\n\nAbstract: Enhancing the adaptive cruise control (ACC) functionality with wireless communication links, in addition to sensors such as radars and/or lidars, cooperative adaptive cruise control (CACC) is facilitated. CACC enables driving at small intervehicle distances, forming a vehicle platoon system, while maintaining string stability (i.e., the disturbance is attenuated along the vehicle string). While string stability is a necessary requirement for the design of vehicle platoons, most of the works are limited to homogeneous vehicles or platoons with a single heterogeneity, which is not often the case in reality. In this work, we make an attempt to provide sufficient conditions for string stability for a very general case of heterogeneous vehicle platoons under the multiple-predecessor following (MPF) topology. More specifically, we focus on the following forms of heterogeneity: different parasitic lags, different time headways, different controller parameters and different communication time delays. First, we obtain sufficient conditions for string stability for the general case. Homogeneous vehicle platoons or platoons with a single heterogeneity constitute special cases. Since providing closed-form expressions for the general case is not feasible, we analyze some simpler, yet practical, cases. In particular, we allow the time headway and the controllers to be identical (this can be part of the design of the vehicle platoons) and we consider the case in which parasitic lags and communication time delays can be different. Case studies are considered in simulations in order to give more insights and limitations of our results.","Title: Fast-Convergent Anytime-Feasible Dynamics for Distributed Allocation of Resources Over Switching Sparse Networks with Quantized Communication Links\nYear: 2022\n\nAbstract: This paper proposes anytime feasible networked dynamics to solve resource allocation problems over time-varying multi-agent networks. The state of agents represents the assigned resources while their total (equal to demand) is constant. The idea is to optimally allocate the resources among the group of agents by minimizing the overall cost subject to fixed sum of resources. Each agent's information is local and restricted to its own state, cost function, and the ones from its immediate neighbors. This work provides a fast convergent solution (compared to linear dynamics) while considering more-relaxed uniform network connectivity and (logarithmic) quantized communications among agents. The proposed dynamics reaches optimal solution over switching (sparsely-connected) undirected networks as far as their union over some bounded non-overlapping time-intervals has a spanning tree. Moreover, we prove anytime-feasibility of the solution, uniqueness, and convergence to the optimal value irrespective of the specific nonlinearity in the proposed dynamics. Such general proof analysis applies to many similar 1st-order allocation dynamics subject to strongly sign-preserving nonlinearities, e.g., actuator saturation in generator coordination. Further, anytime feasibility (despite the nonlinearities) ensures that our solution satisfies the fixed-sum resources constraint at all times.","Title: Distributed Anomaly Detection and Estimation over Sensor Networks: Observational-Equivalence and <tex>$Q$</tex>-Redundant Observer Design\nYear: 2022\n\nAbstract: In this paper, we study stateless and stateful physics-based anomaly detection scenarios via distributed estimation over sensor networks. In the stateful case, the detector keeps track of the sensor residuals (i.e., the difference of estimated and true outputs) and reports an alarm if certain statistics of the recorded residuals deviate over a predefined threshold, e.g., \n<tex xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">$\\chi^{2}$</tex>\n (Chi-square) detector. Instead, only instantaneous deviation of the residuals raises the alarm in the stateless case without considering the history of the sensor outputs and estimation data. Given (approximate) false-alarm rate for both cases, we propose a probabilistic threshold design based on the noise statistics. We show by simulation that increasing the window length in the stateful case may not necessarily reduce the false-alarm rate. On the other hand, it adds unwanted delay to raise the alarm. The distributed aspect of the proposed detection algorithm enables local isolation of the faulty sensors with possible recovery solutions by adding redundant observationally-equivalent sensors. We, then, offer a mechanism to design \n<tex xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">$Q$</tex>\n-redundant distributed observers, robust to failure (or removal) of up to \n<tex xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">$Q$</tex>\n sensors over the network."],"string":"[\n \"Title: Towards distributed transmission scheduling for wireless ad hoc networks.\\nYear: 2012\\n\\nAbstract: In this paper we study distributed transmission scheduling via power control in wireless ad hoc networks with multiple channels. The target for each node is to manage to be admitted into a channel from the available channels in the network. The aim of this work is twofold: (a) to determine how a wireless node, based on its limited information, will decide which channel to access and (b), to propose a distributed algorithm for each wireless node with which once the channel is chosen a decision is made whether to stay in the channel or not. Here, we propose an algorithm that, if adopted by all the nodes in the network, it converges to a solution that admits most of the wireless nodes in the network, based on limited information only. Simulations in MATLAB justify the good performance of the algorithm.\",\n \"Title: Buffer-Aided Successive Opportunistic Relaying With Inter-Relay Interference Cancellation\\nYear: 2013\\n\\nAbstract: In this paper we consider a simple cooperative network consisting of a source, a destination and a cluster of decode-and-forward relays characterized by the half-duplex constraint. At each time-slot the source and (possibly) one of the relays transmit a packet to another relay and the destination, respectively. When the source and a relay transmit simultaneously, inter-relay interference is introduced at the receiving relay. In this work, with the aid of buffers at the relays, we mitigate the detrimental effect of inter-relay interference through either interference cancellation or mitigation. More specifically, we propose the min - power opportunistic relaying protocol that minimizes the total energy expenditure per time slot under an inter-relay interference cancellation scheme. The min - power relay-pair selection scheme, apart from minimizing the energy expenditure, also provides better throughput and lower outage probability than existing works in the literature. The performance of the proposed scheme is demonstrated via illustrative examples and simulations in terms of outage probability and average throughput.\",\n \"Title: Self-adaptive and self-configured CPU resource provisioning for virtualized servers using Kalman filters\\nYear: 2009\\n\\nAbstract: Data center virtualization allows cost-effective server consolidation which can increase system throughput and reduce power consumption. Resource management of virtualized servers is an important and challenging task, especially when dealing with fluctuating workloads and complex multi-tier server applications. Recent results in control theory-based resource management have shown the potential benefits of adjusting allocations to match changing workloads. This paper presents a new resource management scheme that integrates the Kalman filter into feedback controllers to dynamically allocate CPU resources to virtual machines hosting server applications. The novelty of our approach is the use of the Kalman filter-the optimal filtering technique for state estimation in the sum of squares sense-to track the CPU utilizations and update the allocations accordingly. Our basic controllers continuously detect and self-adapt to unforeseen workload intensity changes. Our more advanced controller self-configures itself to any workload condition without any a priori information. Indicatively, it results in within 4.8% of the performance of workload-aware controllers under high intensity workload changes, and performs equally well under medium intensity traffic. In addition, our controllers are enhanced to deal with multi-tier server applications: by using the pair-wise resource coupling between application components, they provide a 3% on average server performance improvement when facing large unexpected workload increases when compared to controllers with no such resource-coupling mechanism. We evaluate our techniques by controlling a 3-tier Rubis benchmark web site deployed on a prototype Xen-virtualized cluster.\",\n \"Title: A Distributed Power Control and Transmission Rate Allocation Algorithm over Multiple Channels\\nYear: 2011\\n\\nAbstract: In this paper, we consider multiple channels and wireless nodes with multiple transceivers. Each node assigns one transmitter at each available channel. For each assigned transmitter the node decides the power level and data rate of transmission in a distributed fashion, such that certain Quality of Service (QoS) demands for the wireless node are satisfied. More specifically, we investigate the case in which the average SINR over all channels for each communication pair is kept above a certain threshold. A joint distributed power and rate control algorithm for each transmitter is proposed that dynamically adjusts the data rate to meet a target SINR at each channel, and to update the power levels allowing for variable desired SINRs. The algorithm is fully distributed and requires only local interference measurements. The performance of the proposed algorithm is shown through illustrative examples.\",\n \"Title: Distributed network size estimation and average degree estimation and control in networks isomorphic to directed graphs.\\nYear: 2012\\n\\nAbstract: Many properties of interest in graph structures are based on the nodes' average degree (i.e., the average number of edges incident to/from each node). In this work, we present asynchronous distributed algorithms, based on ratio consensus, that can be used to accurately estimate the number of nodes in a multi-component system whose communication topology is described by a directed graph. In addition, we describe an asynchronous distributed algorithm that allows each node to introduce or terminate links in order to reach a target average degree in the network. Such an approach can be useful in many realistic scenarios; for example, for the introduction and removal of renewable energy resources in a power network, while maintaining an average degree that fulfils some structural and dynamical properties and/or optimises some performance indicators of the network. The effectiveness of the proposed algorithms is demonstrated via illustrative examples.\",\n \"Title: Neighbor Discovery in Multichannel Wireless Clique Networks: An Epidemic Approach\\nYear: 2013\\n\\nAbstract: We investigate the problem of neighbor discovery in multichannel wireless ad hoc and sensor networks with epidemic information dissemination. Previous works have considered neighbor discovery in a single channel where at most one node can be discovered per time instant. To reduce the effect of collisions observed in single channel solutions, we formulate models for multichannel neighbor discovery and allow for epidemic dissemination of information. As a result, nodes can discover all their neighbors faster, either directly or indirectly by hopping between orthogonal channels and exploring the neighbors in each of them. We show analytically, by simulations, and by experimental evaluations that the expected neighbor discovery time is reduced considerably compared to single channel neighbor discovery solutions.\",\n \"Title: Medium Access Control Via Contention-Based Distributed Power Control\\nYear: 2012\\n\\nAbstract: A successful distributed power control algorithm requires only local measurements for updating the power level of a transmitting node, so that eventually all transmitters meet their QoS requirements. Nevertheless, the problem arises when the QoS requirements cannot be achieved for all the users in the network. In this paper, a distributed algorithm for wireless ad hoc networks which is contention-based and makes use of a back off mechanism is proposed. This algorithm aims to eliminate overhead communication, improve fairness, allow nodes to operate asynchronously while establishing some performance level. The performance of the algorithm is evaluated via simulations.\",\n \"Title: Unconditional stability of the Foschini-Miljanic algorithm.\\nYear: 2012\\n\\nAbstract: In this note we prove the unconditional stability of the Foschini–Miljanic algorithm. Our results show that the Foschini–Miljanic algorithm is unconditionally stable (convergent) even in the presence of bounded time-varying communication delays, and in the presence of topology changes. The implication of our results may be important for the design of Code Division Multiple Access (CDMA) based wireless networks.\",\n \"Title: Stability Analysis and Power Optimization for Energy Harvesting Cooperative Networks.\\nYear: 2012\\n\\nAbstract: In this letter, we investigate the effects of network-layer cooperation in a wireless three-node network with energy-harvesting nodes and bursty data traffic. By modelling energy harvesting in each node as a queue (buffer) that stores the received energy, we study the interaction between data and energy queues when only knowledge of the arrival rates is available. The maximum stable throughput (in...\",\n \"Title: Buffer-Aided Relay Selection for Cooperative Diversity Systems without Delay Constraints.\\nYear: 2012\\n\\nAbstract: In this paper, we study the relay selection problem for a finite buffer-aided decode-and-forward cooperative wireless network. A relay selection policy that fully exploits the flexibility offered by the buffering ability of the relay nodes in order to maximize the achieved diversity gain is investigated. This new scheme incorporates the instantaneous strength of the wireless links as well as the s...\",\n \"Title: Lossless Coding with Generalised Criteria\\nYear: 2011\\n\\nAbstract: This paper presents prefix codes which minimize various criteria constructed as a convex combination of maximum codeword length and average codeword length or maximum redundancy and average redundancy, including a convex combination of the average of an exponential function of the codeword length and the average redundancy. This framework encompasses as a special case several criteria previously investigated in the literature, while relations to universal coding is discussed. The coding algorithm derived is parametric resulting in re-adjusting the initial source probabilities via a weighted probability vector according to a merging rule. The level of desirable merging has implication in applications where the maximum codeword length is bounded.\",\n \"Title: Transmission Scheduling in Wireless Networks with SINR Constraints\\nYear: 2009\\n\\nAbstract: Despite all the work being done so far in scheduling for wireless networks, the transmission scheduling problem with specific constraints is not yet fully understood and explored. In this work, we find the minimum number of time-slots (or channels) required in any given network and the corresponding transmitting powers, such that all communication requests are being processed correctly, while fulfilling specific constraints that comply with the Quality of Service (QoS) requirements for successful transmissions. More specifically, in this paper, we formulate the optimization problem as a Mixed Integer Program (MIP) and solve the mathematical formulation by a Branch-and-Bound algorithm. Our computational study shows that our methodology is capable of solving exactly networks of varying size but can also provide a near optimal heuristic solution for the hardest instances. The results can be used as bounds for the study of distributed algorithms that aim for the optimal scheduling and power assignment without information about the whole network. Numerical examples are provided to illustrate the validity of our proposed methodology.\",\n \"Title: Average Consensus in the Presence of Delays and Dynamically Changing Directed Graph Topologies\\nYear: 2012\\n\\nAbstract: Classical approaches for asymptotic convergence to the global average in a distributed fashion typically assume timely and reliable exchange of information between neighboring components of a given multi-component system. These assumptions are not necessarily valid in practical settings due to varying delays that might affect transmissions at different times, as well as possible changes in the underlying interconnection topology (e.g., due to component mobility). In this work, we propose protocols to overcome these limitations. We first consider a fixed interconnection topology (captured by a - possibly directed - graph) and propose a discrete-time protocol that can reach asymptotic average consensus in a distributed fashion, despite the presence of arbitrary (but bounded) delays in the communication links. The protocol requires that each component has knowledge of the number of its outgoing links (i.e., the number of components to which it sends information). We subsequently extend the protocol to also handle changes in the underlying interconnection topology and describe a variety of rather loose conditions under which the modified protocol allows the components to reach asymptotic average consensus. The proposed algorithms are illustrated via examples.\",\n \"Title: Asymptotic Stability and Decay Rates of Homogeneous Positive Systems With Bounded and Unbounded Delays.\\nYear: 2014\\n\\nAbstract: There are several results on the stability of nonlinear positive systems in the presence of time delays. However, most of them assume that the delays are constant. This paper considers time-varying, possibly unbounded, delays and establishes asymptotic stability and bounds the decay rate of a significant class of nonlinear positive systems which includes positive linear systems as a special case. Specifically, we present a necessary and sufficient condition for delay-independent stability of continuous-time positive systems whose vector fields are cooperative and homogeneous. We show that global asymptotic stability of such systems is independent of the magnitude and variation of the time delays. For various classes of time delays, we are able to derive explicit expressions that quantify the decay rates of positive systems. We also provide the corresponding counterparts for discrete-time positive systems whose vector fields are nondecreasing and homogeneous.\",\n \"Title: Stability and Performance of Continuous-Time Power Control in Wireless Networks.\\nYear: 2014\\n\\nAbstract: This paper develops a comprehensive stability analysis framework for general classes of continuous-time power control algorithms under heterogeneous time-varying delays. Our first set of results establish global asymptotic stability of power control laws involving two-sided scalable interference functions, and include earlier work on standard interference functions as a special case. We then consider contractive interference functions and demonstrate that the associated continuous-time power control laws always have unique fixed points which are exponentially stable, even under bounded heterogeneous time-varying delays. For this class of interference functions, we present explicit bounds on the decay rate that allow us to quantify the impact of delays on the convergence time of the algorithm. When interference functions are linear, we also prove that contractivity is necessary and sufficient for exponential stability of continuous-time power control algorithms with time-varying delays. Finally, numerical simulations illustrate the validity of our theoretical results.\",\n \"Title: Adaptive Resource Provisioning for Virtualized Servers Using Kalman Filters\\nYear: 2014\\n\\nAbstract: Resource management of virtualized servers in data centers has become a critical task, since it enables cost-effective consolidation of server applications. Resource management is an important and challenging task, especially for multitier applications with unpredictable time-varying workloads. Work in resource management using control theory has shown clear benefits of dynamically adjusting resource allocations to match fluctuating workloads. However, little work has been done toward adaptive controllers for unknown workload types. This work presents a new resource management scheme that incorporates the Kalman filter into feedback controllers to dynamically allocate CPU resources to virtual machines hosting server applications. We present a set of controllers that continuously detect and self-adapt to unforeseen workload changes. Furthermore, our most advanced controller also self-configures itself without any a priori information and with a small 4.8% performance penalty in the case of high-intensity workload changes. In addition, our controllers are enhanced to deal with multitier server applications: by using the pair-wise resource coupling between tiers, they improve server response to large workload increases as compared to controllers with no such resource-coupling mechanism. Our approaches are evaluated and their performance is illustrated on a 3-tier Rubis benchmark website deployed on a prototype Xen-virtualized cluster.\",\n \"Title: Sub-homogeneous positive monotone systems are insensitive to heterogeneous time-varying delays.\\nYear: 2014\\n\\nAbstract: We show that a sub-homogeneous positive monotone system with bounded heterogeneous time-varying delays is globally asymptotically stable if and only if the corresponding delay-free system is globally asymptotically stable. The proof is based on an extension of a delay-independent stability result for monotone systems under constant delays by Smith to systems with bounded heterogeneous time-varying delays. Under the additional assumption of positivity and sub-homogeneous vector fields, we establish the aforementioned delay insensitivity property and derive a novel test for global asymptotic stability. If the system has a unique equilibrium point in the positive orthant, we prove that our stability test is necessary and sufficient. Specialized to positive linear systems, our results extend and sharpen existing results from the literature.\",\n \"Title: Modeling Buffer-Aided Relay Selection in Networks With Direct Transmission Capability\\nYear: 2015\\n\\nAbstract: We consider a wireless relay network that consists of a source, half-duplex decode-and-forward buffer-aided relays and a destination. While the majority of previous works on relay selection assume no direct transmission between source and destination in such a setting, we lift this assumption and propose a link selection policy that exploits both the buffering ability and the opportunity for successful reception of a packet directly from the source. The proposed relay selection scheme incorporates the instantaneous strength of the wireless links and adapts the relay selection decision based on the strongest available link. The evolution of the network as a whole is modeled by means of a Markov chain and thus, the outage probability is associated with the steady state of the Markov chain. It is deduced that even if the link between the source and the destination is in principle a very unreliable link, it is always beneficial for the source to multicast a packet to both the relay with the strongest available link and the destination.\",\n \"Title: On the minimum latency transmission scheduling inwireless networks with power control under SINRconstraints\\nYear: 2015\\n\\nAbstract: AbstractIn order to alleviate interference and contention in a wireless network, we may exploit the existence of multiple orthogonal channels or time slots, thus achieving a substantial improvement in performance. In this paper, we study a joint transmission scheduling and power control problem that arises in wireless networks. The goal is to assign channels ortimeslots and transmitting powers to communication links such that all communication requests are processed correctly, specified quality-of-service requirements are met, and the number of required time slots is minimised. First, we formulate the problem as a mixed-integer linear programming. Then, we show that the problem considered is non-deterministic polynomial-time hard, and subsequently, we propose non-trivial bounding techniques to solve it. Optimisation methods are also discussed, including a column generation approach, specifically designed to find bounds for the transmission scheduling problem. Moreover, we develop optimisation techniques in which the bounding techniques are integrated in order to derive the optimal solution to the problem faster. We close with an extensive computational study, which shows that despite the complexity of the problem, the proposed methodology scales to problems of non-trivial size. Our algorithms can therefore be used for static wireless networks where propagation conditions are almost constant and a centralised agent is available e.g. cellular networks where the base station can act as a centralised agent or wireless mesh networks, and they can also serve as a benchmark for the performance evaluation of heuristic, approximation or distributed algorithms that aim to find near-optimal solutions without information about the whole network. Copyright © 2013 John Wiley & Sons, Ltd.\",\n \"Title: Hybrid cooperation through full-duplex opportunistic relaying and max-link relay selection with transmit power adaptation\\nYear: 2014\\n\\nAbstract: In this work, we study a cooperative network with multiple full-duplex buffer-aided relays. A hybrid cooperative relaying policy is proposed that employs power adaptation and consists of two alternative schemes: (i) full-duplex transmission through the relay which requires the least total power expenditure and loop interference is mitigated through power adaptation; (ii) buffer-aided max - link selection with power adaptation, when full-duplexity is not feasible. Aiming to reduce the overhead of channel state information (CSI) acquisition and processing, we propose a suboptimal distributed method for relay selection, for which the network performance is not degraded significantly. We show that power adaptation offers reduced overhead of CSI acquisition. Numerical results and comparisons with other state-of-the-art relaying schemes are provided and performance evaluation in terms of throughput, power minimization and switching rate, show the benefits of the proposed hybrid scheme.\",\n \"Title: Average consensus in the presence of dynamically changing directed topologies and time delays\\nYear: 2014\\n\\nAbstract: We have recently proposed a robustified ratio consensus algorithm which achieves asymptotic convergence to the global average in a distributed fashion in static strongly connected digraphs, despite the possible presence of bounded but otherwise arbitrary delays. In this work, we propose a protocol which reaches asymptotic convergence to the global average in a distributed fashion under possible changes in the underlying interconnection topology (e.g., due to component mobility), as well as time-varying delays that might affect transmissions at different times. More specifically, we extend our previous work to also account for the case where, in addition to arbitrary but bounded delays, we may have time varying communication links. The proposed protocol requires that each component has knowledge of the number of its outgoing links, perhaps with some bounded delay, and that the digraphs formed by the switching communication topologies over a finite time window are jointly strongly connected.\",\n \"Title: Average Consensus in the Presence of Delays in Directed Graph Topologies\\nYear: 2014\\n\\nAbstract: Classical distributed algorithms for asymptotic average consensus typically assume timely and reliable exchange of information between neighboring components of a given multi-component system. These assumptions are not necessarily valid in practice due to varying delays that might affect computations at different nodes and/or transmissions at different links. In this work, we propose a protocol that overcomes this limitation and, unlike existing consensus protocols in the presence of delays, ensures asymptotic consensus to the exact average, despite the presence of arbitrary (but bounded) delays in the communication links. The protocol requires that each component has knowledge of the number of its out-neighbors (i.e., the number of components to which it can send information) and its proof of correctness relies on the weak convergence of a backward product of column stochastic matrices. The proposed algorithm is demonstrated via illustrative examples.\",\n \"Title: Precoding decision for full-duplex X-relay channel with Decode-and-Forward\\nYear: 2014\\n\\nAbstract: In this paper, we study a simple X-relay configuration where the shared relay operates in full-duplex (FD) mode. The relay node may have limited spatial degrees of freedom, and as a result, it may not be able to handle both the loop interference and the multiuser interference. Hence, a decision on the precoding scheme is necessitated. It is often the case that the relay does not have the option of real-time switching between different precoding schemes, either due to hardware limitations of the relay or increased complexity of the problem. Hence, we investigate a “static” precoding decision where the relay node decides on its precoding scheme based only on statistical knowledge of the channel conditions. To perform this decision, the behavior of the system is formulated as a Markov chain and the outage probability of the system is derived in a closed-form with the precoding decision as a parameter. The outage probability is minimized by optimally choosing the precoding scheme, using easily verifiable conditions on the statistical knowledge of the channel conditions. Simulations validate the investigated scheme.\",\n \"Title: Exponential Stability of Homogeneous Positive Systems of Degree One With Time-Varying Delays\\nYear: 2013\\n\\nAbstract: While the asymptotic stability of positive linear systems in the presence of bounded time delays has been thoroughly investigated, the theory for nonlinear positive systems is considerably less well-developed. This technical note presents a set of conditions for establishing delay-independent stability and bounding the decay rate of a significant class of nonlinear positive systems which includes positive linear systems as a special case. Specifically, when the time delays have a known upper bound, we derive necessary and sufficient conditions for exponential stability of: a) continuous-time positive systems whose vector fields are homogeneous and cooperative and b) discrete-time positive systems whose vector fields are homogeneous and order-preserving. We then present explicit expressions that allow us to quantify the impact of delays on the decay rate and show that the best decay rate of positive linear systems that our bounds provide can be found via convex optimization. Finally, we extend the results to general linear systems with time-varying delays.\",\n \"Title: Extremum Problems With Total Variation Distance and Their Applications\\nYear: 2014\\n\\nAbstract: The aim of this paper is to investigate extremum problems with pay-off being the total variation distance metric defined on the space of probability measures, subject to linear functional constraints on the space of probability measures, and vice-versa; that is, with the roles of total variation metric and linear functional interchanged. Utilizing concepts from signed measures, the extremum probability measures of such problems are obtained in closed form, by identifying the partition of the support set and the mass of these extremum measures on the partition. The results are derived for abstract spaces; specifically, complete separable metric spaces known as Polish spaces, while the high level ideas are also discussed for denumerable spaces endowed with the discrete topology. These extremum problems often arise in many areas, such as, approximating a family of probability distributions by a given probability distribution, maximizing or minimizing entropy subject to total variation distance metric constraints, quantifying uncertainty of probability distributions by total variation distance metric, stochastic minimax control, and in many problems of information, decision theory, and minimax theory.\",\n \"Title: Optimal Merging Algorithms for Lossless Codes With Generalized Criteria\\nYear: 2014\\n\\nAbstract: This paper presents lossless prefix codes optimized with respect to a payoff criterion consisting of a convex combination of maximum codeword length and average codeword length. The optimal codeword lengths obtained are based on a new coding algorithm, which transforms the initial source probability vector into a new probability vector according to a merging rule. The coding algorithm is equivalent to a partition of the source alphabet into disjoint sets on which a new transformed probability vector is defined as a function of the initial source probability vector and scalar parameter. The payoff criterion considered encompasses a tradeoff between maximum and average codeword length; it is related to a payoff criterion consisting of a convex combination of average codeword length and average of an exponential function of the codeword length, and to an average codeword length payoff criterion subject to a limited length constraint. A special case of the first related payoff is connected to coding problems involving source probability uncertainty and codeword overflow probability, whereas the second related payoff compliments limited length Huffman coding algorithms.\",\n \"Title: On the stability of the Foschini-Miljanic algorithm with time-delays\\nYear: 2008\\n\\nAbstract: Many of the distributed power control algorithms for wireless networks in the literature ignore the fact that while the algorithms necessitate communication among users, propagation delays exist in the network. This problem is of vital importance, since propagation delays are omnipresent in wireless networks. The Foschini-Miljanic algorithm is provably stable if there are no time-delays in the execution of the algorithm. However, since the interference measurements are fed back to the transmitter by its corresponding receiver, time- delays are inevitably introduced into the system. This work presents a more realistic version of the well known Foschini- Miljanic algorithm for Distributed Power Control since it considers the time-delays introduced to the system due to propagation delays. In both the continuous and discrete time cases we prove global stability of the system in the presence of propagation delays. Our work is focused on power adaptation in an envi- ronment where there exist propagation delays between the communicating pairs. That is, we consider the fact that the interference measurement is not available at the transmitter instantaneously but with some time-delay. This considera- tion is important and reasonable since there are inevitable propagation delays, something that makes the model of the network more realistic. We consider the same distributed power control algorithm as in (2), but we introduce time- delays at the interference measurements of the receiver that are fed back to the transmitter. Within this setting we prove stability for the continuous-time and discrete- time FM algorithm. More specifically, using the multivariate Nyquist criterion (8) and by determining the set in which the spectrum of the multivariate system lies, we prove that both the continuous and discrete time FM algorithms are globally asymptotically stable (GAS) for arbitrarily large delays. These results indicate that the FM algorithm, compared to other power control algorithms (9), is suitable to be used in any network without requiring any bound on time-delays. The rest of this paper is organized as follows. In the next section, the system model along with the necessary preliminary results are presented, while in section III a brief review of the FM algorithm, both continuous and discrete time, is given. In section IV the stability of those algorithms in the presence of time delays is proven. In section V, we continue with illustrative examples of the results presented. Finally, the conclusions are drawn in section VI.\",\n \"Title: Dynamic programming with total variational distance uncertainty\\nYear: 2012\\n\\nAbstract: The aim of this paper is to address optimality of stochastic control strategies via dynamic programming subject to total variational distance uncertainty on the conditional distribution of the controlled process. Utilizing concepts from signed measures, the maximization of a linear functional on the space of probability measures on abstract spaces is investigated, among those probability measures which are within a total variational distance from a nominal probability measure. The maximizing probability measure is found in closed form. These results are then applied to solve minimax stochastic control with deterministic control strategies, under a Markovian assumption on the conditional distributions of the controlled process. The results include: 1) Optimization subject to total variational distance constraints, 2) new dynamic programming recursions, which involve the oscillator seminorm of the value function.\",\n \"Title: Asymptotic stability and decay rates of positive linear systems with unbounded delays\\nYear: 2013\\n\\nAbstract: There are several results on the stability analysis of positive linear systems in the presence of constant or time-varying delays. However, most existing results assume that the delays are bounded. This paper studies the stability of discrete-time positive linear systems with unbounded delays. We provide a set of easily verifiable necessary and sufficient conditions for delay-independent stability of positive linear systems subject to a general class of heterogeneous time-varying delays. For two particular classes of unbounded delays, explicit expressions that bound the decay rate of the system are presented. We demonstrate that the best bound on the decay rate that our results can guarantee can be found via convex optimization. Finally, the validity of the results is demonstrated via a numerical example.\",\n \"Title: Extremum problems with total variation distance\\nYear: 2013\\n\\nAbstract: The aim of this paper is to investigate extremum problems with pay-off the total variational distance metric subject to linear functional constraints both defined on the space of probability measures, as well as related problems. Utilizing concepts from signed measures, the extremum probability measures of such problems are obtained in closed form, by identifying the partition of the support set and the mass of these extremum measures on the partition. The results are derived for abstract spaces, specifically, complete separable metric spaces, while the high level ideas are also discussed for denumerable spaces endowed with the discrete topology.\",\n \"Title: Opportunistic relay selection for cooperative networks with buffers\\nYear: 2012\\n\\nAbstract: In this paper, a relay selection policy is proposed that fully exploits the flexibility offered by the buffering ability of the relay nodes in order to maximize the achieved diversity gain. The suggested scheme incorporates the instantaneous strength of the wireless links as well as the status of the finite relay buffers and the relay selection decision is based on the strongest available link. Hence the switching occurs dynamically between relay reception and transmission. We show that the proposed relay selection scheme significantly outperforms conventional relay selection policies for all cases and ensures a diversity gain equal to two times the number of relays for large buffer sizes.\",\n \"Title: A Buffer-aided Successive Opportunistic Relay Selection Scheme with Power Adaptation and Inter-Relay Interference Cancellation for Cooperative Diversity Systems\\nYear: 2013\\n\\nAbstract: In this paper, we present a relay selection scheme which combines the spectral efficiency of successive opportunistic relaying with the robustness of single-link relay selection. More specifically, we propose a scheme that minimizes the total energy expenditure per time slot under an inter-relay interference cancellation scheme. The new relay selection policy is analyzed in terms of outage probability and diversity by modeling the evolution of relay buffers as a Markov Chain. We construct the state transition matrix of the Markov Chain and obtain its stationary distribution, which in turn, yields the outage probability. The proposed scheme outperforms relevant state-of-the-art relay selection schemes in terms of throughput, diversity, energy efficiency and average delay, as demonstrated via representative numerical examples.\",\n \"Title: Dynamic Programming Subject to Total Variation Distance Ambiguity.\\nYear: 2015\\n\\nAbstract: The aim of this paper is to address optimality of stochastic control strategies via dynamic programming subject to total variation distance ambiguity on the conditional distribution of the controlled process. We formulate the stochastic control problem using minimax theory, in which the control minimizes the payoff while the conditional distribution, from the total variation distance set, maximizes it. First, we investigate the maximization of a linear functional on the space of probability measures on abstract spaces, among those probability measures which are within a total variation distance from a nominal probability measure, and then we give the maximizing probability measure in closed form. Second, we utilize the solution of the maximization to solve minimax stochastic control with deterministic control strategies, under a Markovian and a non-Markovian assumption, on the conditional distributions of the controlled process. The results of this part include (1) minimax optimization subject to total variation distance ambiguity constraint; (2) new dynamic programming recursions, which involve the oscillator seminorm of the value function, in addition to the standard terms; and (3) a new infinite horizon discounted dynamic programming equation, the associated contractive property, and a new policy iteration algorithm. Finally, we provide illustrative examples for both the finite and infinite horizon cases. For the infinite horizon case, we invoke the new policy iteration algorithm to compute the optimal strategies.\",\n \"Title: Filtering With Fidelity For Time-Varying Gauss-Markov Processes\\nYear: 2016\\n\\nAbstract: In this paper, we revisit the relation between Nonanticipative Rate Distortion (NRD) theory and real-time realizable filtering theory. Specifically, we give the closed form expression for the optimal nonstationary (time-varying) reproduction distribution of the Finite Time Horizon (FTH) Nonanticipative Rate Distortion Function (NRDF) and we establish its connection to real-time realizable filtering theory via a realization scheme utilizing time-varying fully observable multidimensional Gauss-Markov processes. As an application we provide the optimal filter with respect to a mean square error constraint. Unlike classical filtering theory, our filtering approach based on FTH NRDF is performed with waterfilling. We also derive a universal lower bound to the mean square error of any causal estimator to Gaussian processes based on the closed form expression of FTH NRDF. Our theoretical results are demonstrated via an illustrative example.\",\n \"Title: Fast Information Exchange in Proximity-Based Multichannel Wireless Networks\\nYear: 2015\\n\\nAbstract: This paper considers the problem of distributed neighbor discovery in multi-channel wireless networks. We propose a protocol in which nodes randomly select a channel and decide whether to transmit or listen for neighbor discovery beacons. When nodes transmit, they use epidemic information dissemination to spread knowledge about all the nodes they have discovered so far. Theoretical guarantees on discovery times are complemented by extensive simulations and practical implementations. The evaluations show that multi-channel communication effectively reduces the number of collisions between nodes in the network (especially in dense networks) and that epidemic information dissemination yields both significant speed-ups and increased resilience to packet losses. Finally, we also show that our protocol compares favorably to previously proposed solutions in the literature.\",\n \"Title: A Survey on Buffer-Aided Relay Selection.\\nYear: 2016\\n\\nAbstract: Relays receive and retransmit signals between one or more sources and one or more destinations. Cooperative relaying is a novel technique for wireless communications that increases throughput and extends the coverage of networks. The task of relay selection serves as a building block to realize cooperative relaying. Recently, relays with buffers have been incorporated into cooperative relaying pro...\",\n \"Title: A delay-aware hybrid relay selection policy\\nYear: 2016\\n\\nAbstract: In this paper, we propose a novel relay selection policy based on the Hybrid Relay Selection (HRS) relay selection protocol that takes into account the state of the buffers and aims at reducing the average packet delays in the network. The proposed protocol, called the Delay-Aware HRS (DA - HRS) protocol is analyzed by means of Markov Chains and expressions for the outage probability, throughput and delay are derived. The distributed implementation of the protocol is also discussed. The performance of our proposed protocol is demonstrated via extensive simulations and comparisons with the classical HRS.\",\n \"Title: Location-Aided Pilot Decontamination for Massive MIMO Systems.\\nYear: 2016\\n\\nAbstract: One of the key limitation of massive MIMO systems is pilot contamination, which is defined as the interference during uplink channel estimation due to re-use of the same pilots in surrounding cells. In this paper, we propose a location-based approach to the pilot contamination problem for uplink MIMO systems. Our approach makes use of the approximate locations of mobile devices to provide good estimates of the channel statistics between the mobile devices and their corresponding base stations (BSs). We aim at minimizing the pilot contamination even when the number of BS antennas is not very large, and when multiple users from different cells, or even the same cell, are assigned the same pilot sequence. First, we characterize a desired angular region of the target user at the target BS in which interference is very low or zero, based on the number of BS antennas and the location of the target user. Second, based on this observation, we propose various pilot coordination methods for multi-user multi-cell scenarios to eliminate pilot contamination.\",\n \"Title: Infinite Horizon Discounted Dynamic Programming Subject To Total Variation Ambiguity On Conditional Distribution\\nYear: 2016\\n\\nAbstract: We analyze the infinite horizon minimax discounted cost Markov Control Model (MCM), for a class of controlled process conditional distributions, which belong to a ball, with respect to total variation distance metric, centered at a known nominal controlled conditional distribution with radius R is an element of [0,2], in which the minimization is over the control strategies and the maximization is over conditional distributions. Through our analysis (i) we derive a new discounted dynamic programming equation, (ii) we show the associated contraction property, and (iii) we develop a new policy iteration algorithm. Finally, the application of the new dynamic programming and the corresponding policy iteration algorithm are shown via an illustrative example.\",\n \"Title: Totally Asynchronous Distributed Estimation Of Eigenvector Centrality In Digraphs With Application To The Pagerank Problem\\nYear: 2016\\n\\nAbstract: We propose a distributed coordination mechanism which enables nodes in a directed graph to accurately estimate their eigenvector centrality (eigencentrality) even if they update their values at times determined by their own clocks. The clocks need neither be synchronized nor have the same speed. The main idea is to let nodes adjust the weights on outgoing links to compensate for their update speed: the higher the update frequency, the smaller the link weights.Our mechanism is used to develop a distributed algorithm for computing the PageRank vector, commonly used to assign importance to web pages and rank search results. Although several distributed approaches in the literature can deal with asynchronism, they cannot handle the different update speeds that occur when servers have heterogeneous computational capabilities. When existing algorithms are executed using heterogeneous update speeds, they compute incorrect PageRank values. The advantages of our algorithm over existing approaches are verified through illustrative examples.\",\n \"Title: Robust Linear Quadratic Regulator For Uncertain Systems\\nYear: 2016\\n\\nAbstract: This paper develops a Linear Quadratic Regulator (LQR), which is robust to disturbance variability, by using the total variation distance as a metric. The robust LQR problem is formulated as a minimax optimization problem, resulting in a robust optimal controller which in addition to minimizing the quadratic cost it also minimizes the level of disturbance variability. A procedure for solving the LQR problem is also proposed and an example is presented which clearly illustrates the effectiveness of our developed methodology.\",\n \"Title: Optimal Scheduling Of Downlink Communication For A Multi-Agent System With A Central Observation Post\\nYear: 2018\\n\\nAbstract: In this letter, we consider a set of agents, which may receive an observation of their state by a central observation post via a shared wireless network. The aim of this letter is to design a scheduling mechanism for the central observation post to decide how to allocate the available communication resources. The problem is tackled in two phases: first, the local controllers are designed so as to stabilize the subsystems for the case of perfect communication and second, the communication schedule is decided with the aim of maximizing the stability of the subsystems. To this end, we formulate an optimization problem which explicitly minimizes the Lyapunov function increase due to communication limitations. We show how the proposed optimization can be expressed in terms of value of information, we prove Lyapunov stability in probability and we test our approach in simulations.\",\n \"Title: Relay Pair Selection with Source Precoding in Buffer-Aided Successive Opportunistic Relaying.\\nYear: 2017\\n\\nAbstract: We study a cooperative network with a buffer-aided multi-antenna source, multiple half-duplex (HD) buffer-aided relays and a single destination. Such a setup could represent a cellular downlink scenario, in which the source can be a more powerful wireless device with a buffer and multiple antennas, while a set of intermediate less powerful devices are used as relays to reach the destination. The main target is to recover the multiplexing loss of the network by having the source and a relay to simultaneously transmit their information to another relay and the destination, respectively. Successive transmissions in such a cooperative network, however, cause inter-relay interference (IRI). First, by assuming global channel state information (CSI), we show that the detrimental effect of IRI can be alleviated by precoding at the source, mitigating or even fully canceling the interference. A cooperative relaying policy is proposed that employs a joint precoding design and relay-pair selection. Note that both fixed rate and adaptive rate transmissions can be considered. For the case when channel state information is only available at the receiving side (CSIR), we propose a relay selection policy that employs a phase alignment technique to reduce the IRI. The performance of the two proposed relay pair selection policies are evaluated and compared with other state-of-the-art relaying schemes in terms of outage and throughput. The results show that the use of a powerful source can provide considerable performance improvements.\",\n \"Title: Loco - Link: A Low-Complexity Link Selection Algorithm For Delay Mitigation In Asymmetric Two-Hop Networks\\nYear: 2017\\n\\nAbstract: While buffer-aided relaying improves the diversity of a multi-hop network, its deployment introduces time-delays, thus rendering buffering unreliable for delay-intolerant applications. To alleviate excessive delays, various studies propose delay-aware protocols, but at the expense of reduced diversity, and consequently, increased outage probability. Attempts to maintain the diversity of the system while trying to reduce delays, however, may lead to even higher delays, especially in asymmetric topologies. In this work, we propose a Low-Complexity (LoCo) link selection algorithm, herein called LoCo - Link, that aims at reducing packet delays and enhancing the performance of practical asymmetric two-hop networks. The complexity of LoCo - Link is derived and compared with other state-of-the-art relay selection policies. The performance of the proposed algorithm is evaluated in terms of outage probability, average throughput and average delay, focusing on scenarios with asymmetric links.\",\n \"Title: Dynamic Cpu Resource Provisioning In Virtualized Servers Using Maximum Correntropy Criterion Kalman Filters\\nYear: 2017\\n\\nAbstract: Virtualized servers have been the key for the efficient deployment of cloud applications. As the application demand increases, it is important to dynamically adjust the CPU allocation of each component in order to save resources for other applications and keep performance high, e.g., the client mean response time (mRT) should be kept below a Quality of Service (QoS) target. In this work, a new form of Kalman filter, called the Maximum Correntropy Criterion Kalman Filter (MCC-KF), has been used in order to predict, and hence, adjust the CPU allocations of each component while the RUBiS auction site workload changes randomly as the number of clients varies. MCC-KF has shown high performance when the noise is non-Gaussian, as it is the case in the CPU usage. Numerical evaluations compare our designed framework with other current state-of-the-art using real-data via the RUBiS benchmark website deployed on a prototype Xen-virtualized cluster.\",\n \"Title: Incremental 2d Delaunay Triangulation Core Implementation On Fpga For Surface Reconstruction Via High-Level Synthesis\\nYear: 2017\\n\\nAbstract: This paper presents a 2D Delaunay triangulation core for surface reconstruction implemented on a Field Programmable Gate Array (FPGA) chip. The core implementation is derived using high-level synthesis from a C++ description of an incremental 2D Delaunay triangulation algorithm. This description was modified accordingly so that it can be embedded into a FPGA chip using hardware description language. Goal of this work is to increase the execution speed of the algorithm so as to allow for real-time operation. Towards this end, we performed an optimization process using high level synthesis directives which pipeline regions of the code in order to achieve delay optimization. We show preliminary results using standard benchmark models for surface reconstruction, which show the performance of our design.\",\n \"Title: On The Resource Allocation Problem In Wireless Networked Control Systems\\nYear: 2017\\n\\nAbstract: This paper considers the scheduling problem of a decentralized system where a number of dynamical subsystems with no computational power are scheduled to transmit their measurements via a resource-limited communication network to a remote decision maker who acts as an estimator, controller and scheduler for the subsystems. We propose a new approach for communication resource allocation for a wide class of objective functions, for both coupled and decoupled systems, and for both scheduling observations as well as control commands. This framework facilitates scheduling over a finite horizon and can explicitly deal with stochastic channels. For decoupled subsystems, we propose the notion of cost of information loss (CoIL) and we demonstrate that the communications resource allocation problem can be directly expressed in terms of CoIL functions as an assignment-type optimization problem. Illustrative examples demonstrate how communication resources affect the performance of the system.\",\n \"Title: Location-Aided Pilot Contamination Avoidance for Massive MIMO Systems.\\nYear: 2018\\n\\nAbstract: Pilot contamination, defined as the interference during the channel estimation process due to reusing the same pilot sequences in neighboring cells, can severely degrade the performance of massive multiple-input multiple-output systems. In this paper, we propose a location-based approach to mitigating the pilot contamination problem for uplink multiple-input multiple-output systems. Our approach m...\",\n \"Title: Distributed Averaging andBalancing in Network Systems: with Applications to Coordination and Control\\nYear: 2018\\n\\nAbstract: AbstractRapid developments in digital system and networking technologieshave led to the emergence of complex systems that are defacto managed and controlled over cyber infrastructures, such aswireless and wired broadband networks. The emergence of thistype of network systems, which range from smart grids and trafficnetworks of various sorts, to embedded electronic devices androbotic networks, has sparked huge interest in distributed controlproblems. This is due to the need to properly coordinate the informationexchange between sensors, actuators, and controllersin order to enforce a desirable behavior, without relying on acentralized decision maker. In this monograph, we present somerecent progress in this area by focusing on the key operations ofdistributed average consensus and weight/flow balancing under avariety of communication topologies and adversarial network conditions,e.g., delays, and packet drops. These operations are key incontrol, coordination, and optimization tasks in many emergingapplications; two of these, which we discuss in detail, are thecoordination of distributed energy resources, and the computationof PageRank values.\",\n \"Title: Channel Prediction With Location Uncertainty for Ad Hoc Networks.\\nYear: 2018\\n\\nAbstract: Multiagent systems (MAS) rely on positioning technologies to determine their physical location, and on wireless communication technologies to exchange information. Both positioning and communication are affected by uncertainties, which should be accounted for. This paper considers an agent placement problem to optimize end-to-end communication quality in a MAS in the presence of uncertainties. Usi...\",\n \"Title: Power Adaptation In Buffer-Aided Full-Duplex Relay Networks With Statistical Csi\\nYear: 2018\\n\\nAbstract: In networks with multiple wireless nodes and especially in fast changing environments, the continuous acquisition of channel state information (CSI) may become infeasible. In this correspondence paper, we study the relay selection problem for a cooperative network, where full-duplex relays are equipped with buffers and only statistical CSI is available at the transmitters (CSIT). For this setting, a novel relay selection algorithm is proposed, named HyQoS, relying only on statistical CSIT and performing power adaptation. HyQoS solves an optimization problem for selecting the optimal set of relays. We consider two optimization approaches, first, minimization of the total power consumed in the network, and, second, maximization of the throughput per energy unit, while guaranteeing a specific quality of service, in terms of successful transmission probability. The power allocation problem is formulated as a nonlinear optimization one, taking into account inter-relay interference and residual loop interference. Numerical results show that HyQoS can reduce the power expenditure and increase the throughput, by using only statistical CSIT.\",\n \"Title: Low-Complexity Buffer-Aided Link Selection With Outdated CSI and Feedback Errors.\\nYear: 2018\\n\\nAbstract: Buffer-aided relays can improve the diversity of multi-hop networks, however, they increase packet delays. Thus, various delay-aware protocols have been developed, but without considering the transmission diversity. Moreover, most works adopt ideal assumptions, such as symmetric links, perfect channel state information (CSI), and error-free feedback channels. So, we propose a low-complexity (LoCo)...\",\n \"Title: Robust Dynamic CPU Resource Provisioning in Virtualized Servers\\nYear: 2018\\n\\nAbstract: We present robust dynamic resource allocation mechanisms to allocate application resources meeting Service Level Objectives (SLOs) agreed between cloud providers and customers. In fact, two filter-based robust controllers, i.e., $\\\\mathcal {H}_{\\\\infty }$<mml:mi math...\",\n \"Title: When To Stop Iterating In Digraphs Of Unknown Size? An Application To Finite-Time Average Consensus\\nYear: 2018\\n\\nAbstract: In multi-agent systems, existing distributed algorithms for finite-time average consensus allow the agents to calculate the exact average in finite time, but typically require the agents to continue the iterative process indefinitely. The problem is that it is impossible for one agent to be certain that all other agents have also computed the average (at least not without a priori bounds on the network size or diameter). In this paper, we enhance an existing finite-time distributed algorithm with a distributed termination mechanism that allows the nodes to agree on terminating their iterations when they have all computed the exact average. This is accomplished by exploiting the fact that the distributed algorithm allows each node to compute, in a finite number of steps, an upper bound of its eccentricity in the network. The proposed distributed termination mechanism also facilitates the computation, in a finite number of steps, of an upper bound on the diameter of the network, which can be used by several algorithms that require such global information. Illustrative examples demonstrate the validity and performance of the proposed algorithm.\",\n \"Title: Towards A Robust Traffic Admission Control In Homogeneous Urban Vehicular Networks Under Qos Constraints\\nYear: 2018\\n\\nAbstract: In this paper, we consider the problem of controlling the input flow to a homogeneous urban vehicular network such that certain Quality of Service (QoS) constraints are preserved. In such a network, we model the system with two types of queues: external and internal. External queues represent vehicles waiting to enter the urban vehicular network under control, and the internal queue is used to describe the network's aggregated behavior based on the Network Fundamental Diagram (NFD). While most of the works assume perfect knowledge of the NFD describing the urban vehicular network, in reality we can only approximate it. On these grounds, by taking a model of the NFD with uncertainties, we propose a robust control design approach in order to gate input flow to a protected urban vehicular network such that travel time Quality of Service (QoS) constraints are preserved within the network. The proposed controller is compared via simulations with controllers assuming perfect knowledge of the NFD and it is shown that it can provide a larger stability region.\",\n \"Title: Impact Of Communication Frequency On Remote Control Of Automated Vehicles\\nYear: 2018\\n\\nAbstract: This paper investigates the impact of the communication frequency on the remote control of automated vehicles. In particular, we consider a remote controller, which receives vehicles' state information and issues control commands based on a model predictive control (MPC) framework, to steer the vehicles to reach their respective target position intervals at given specific times. We present a framework where both state information (from the vehicles to the controller) and control actions (from the controller to the vehicles) are communicated through a wireless network. Due to limited communication resources and possible channel impairments, information is not necessarily always provided to the destination (either the controller or the vehicles). Herein, we particularly focus on the communications to the controller and investigate the effect of frequency and last instant of communication. Our results quantify the impact of these factors on the system performance, and subsequently, underline the need for an efficient resource allocation scheme.\",\n \"Title: Asymptotic Reverse-Waterfilling Characterization of Nonanticipative Rate Distortion Function of Vector-Valued Gauss-Markov Processes with MSE Distortion\\nYear: 2018\\n\\nAbstract: We analyze the asymptotic nonanticipative rate distortion function (NRDF) of vector-valued Gauss-Markov processes subject to a mean-squared error (MSE) distortion function. We derive a parametric characterization in terms of a reverse-waterfilling algorithm, that requires the solution of a matrix Riccati algebraic equation (RAE). Further, we develop an algorithm reminiscent of the classical reverse-waterfilling algorithm that provides an upper bound to the optimal solution of the reverse-waterfilling optimization problem, and under certain cases, it operates at the NRDF. Moreover, using the characterization of the reverse-waterfilling algorithm, we derive the analytical solution of the NRDF, for a simple two-dimensional parallel Gauss-Markov process. The efficacy of our proposed algorithm is demonstrated via an example.\",\n \"Title: Laplacian-Based Matrix Design For Finite-Time Average Consensus In Digraphs\\nYear: 2018\\n\\nAbstract: In this paper, we consider the problem of assigning time-varying weights on the links of a time-invariant digraph, such that average consensus is reached in a finite number of steps. More specifically, we derive a finite set of weight matrices that are based on the Laplacian and the Laplacian eigenvalues of the given digraph, such that the product of these weight matrices (in any order) leads to a rank-one matrix. Using the weights associated with this sequence of weight matrices, the nodes run two linear iterations (each with its own initial conditions) and, after a finite number of steps, can calculate the average of the initial values by taking the ratio of the two values they possess at the end of the iteration process. As in the case of undirected graphs, we show that the set of matrices depends on the number of nonzero distinct eigenvalues of the Laplacian matrix. However, unlike the case for undirected graphs, the Laplacian matrix is no longer symmetric, and the number of steps depends not only on the number of distinct eigenvalues but also on their algebraic multiplicities. Illustrative examples demonstrate the validity of the derived results.\",\n \"Title: Optimal Estimation via Nonanticipative Rate Distortion Function and Applications to Time-Varying Gauss--Markov Processes\\nYear: 2018\\n\\nAbstract: In this paper, we develop finite-time horizon causal filters for general processes taking values in Polish spaces using the nonanticipative rate distortion function (NRDF). Subsequently, we apply the NRDF to design optimal filters for time-varying vector-valued Gauss-Markov processes, subject to a mean-squared error (MSE) distortion. Unlike the classical Kalman filter design, the developed filters based on the NRDF are characterized parametrically by a dynamic reverse-waterfilling optimization problem obtained via Karush-Kuhn-Tucker conditions. We develop algorithms that provide, in general, tight upper bounds to the optimal solution to the dynamic reverse-waterfilling optimization problem subject to a total and per-letter MSE distortion constraint. Under certain conditions, these algorithms produce the optimal solutions. Further, we establish a universal lower bound on the total and per-letter MSE of any estimator of a Gaussian random process. Our theoretical framework is demonstrated via simple examples.\",\n \"Title: A Timer-Based Distributed Channel Access Mechanism in Networked Control Systems.\\nYear: 2018\\n\\nAbstract: We consider a system consisting of multiple heterogeneous control subsystems sharing a common communication resource for accomplishing their control tasks. Despite the numerous advantages that such networked control systems (NCSs) offer, their implementation is limited in practice due to the limited communication resources. We propose a novel distributed approach for the resource allocation proble...\",\n \"Title: Relay-pair selection in buffer-aided successive opportunistic relaying using a multi-antenna source\\nYear: 2019\\n\\nAbstract: We study a cooperative network with a buffer-aided multi-antenna source, multiple half-duplex (HD) buffer-aided relays and a single destination. Such a setup could represent a cellular downlink scenario, in which the source can be a more powerful wireless device with a buffer and multiple antennas, while a set of intermediate less powerful devices are used as relays to reach the destination. The main target is to recover the multiplexing loss of the network by having the source and a relay to simultaneously transmit their information to another relay and the destination, respectively. Successive transmissions in such a cooperative network, however, cause inter-relay interference (IRI). First, by assuming global channel state information (CSI), we show that the detrimental effect of IRI can be alleviated by precoding at the source, mitigating or even fully cancelling the interference. A cooperative relaying policy is proposed that employs a joint precoding design and relay-pair selection. Note that both fixed rate and adaptive rate transmissions can be considered. For the case when channel state information is only available at the receiver side (CSIR), we propose a relay selection policy that employs a phase alignment technique to reduce the IRI. The performance of the two proposed relay pair selection policies are evaluated and compared with other state-of-the-art relaying schemes in terms of outage and throughput. The results show that the use of a powerful source can provide considerable performance improvements.\",\n \"Title: Power Allocation for Type-I ARQ Two-Hop Cooperative Networks for Ultra-Reliable Communication.\\nYear: 2019\\n\\nAbstract: We analyze the performance of amplify-and-forward (AF) automatic repeat request (ARQ) for a two-hop cooperative system with reliability constrains. For this setup, we first derive the closed-form outage probability expression. Next, we present a power allocation scheme that allows us to achieve a target outage probability, while minimizing the outage-weighted average power expenditure for asymmetric power allocation between the source and relay. This is cast as an optimization problem, and the optimal power allocation (OPA) is obtained in closed form by invoking the Karush-Kuhn-Tucker (KKT) conditions. We evaluate numerically the OPA strategy between different AF-ARQ transmission rounds and we show that the proposed scheme provides large power gains with respect to the optimized point-to-point ARQ scheme, as well as with respect to the equal power allocation (EPA) strategy.\",\n \"Title: Hybrid NOMA/OMA with Buffer-Aided Relay Selection in Cooperative Networks\\nYear: 2019\\n\\nAbstract: Non-orthogonal multiple access (NOMA) aims to increase the spectral efficiency of fifth generation networks by relaxing the orthogonal use of radio-resources. In this paper, a network with multiple half-duplex buffer-aided (BA) relays is considered, where the source transmits with a fixed rate toward two users. The users might demand the same rate by the source (e.g., two cellular users requiring ...\",\n \"Title: Bandit-Based Power Control in Full-Duplex Cooperative Relay Networks\\nYear: 2021\\n\\nAbstract: Full-duplex relaying is an enabling technique of sixth generation (6G) mobile networks, promising tremendous rate and spectral efficiency gains. In order to improve the performance of full-duplex communications, power control is a viable way of avoiding excessive loop interference at the relay. Unfortunately, power control requires channel state information of both source-relay and relay-destination channels, as well as of the loop interference channel, thus resulting in increased overheads. Aiming to offer a low-complexity alternative for power control in full-duplex relay networks, we adopt reward-based learning in the sense of multi-armed bandits. More specifically, we provide bandit-based power control algorithms, relying on acknowledgements/negative-acknowledgements observations by the relay. The proposed algorithms avoid the need for channel state information acquisition and exchange, and can be employed in a distributed manner. Performance evaluation results in terms of outage probability, average throughput and accumulated regret over time highlight an interesting performance-complexity trade-off compared to optimal power control with full channel knowledge and significant performance gains over the cases without power control and random power level selection.\",\n \"Title: Distributed Detection and Mitigation of Biasing Attacks Over Multi-Agent Networks\\nYear: 2021\\n\\nAbstract: This paper proposes a distributed attack detection and mitigation technique based on distributed estimation over a multi-agent network, where the agents take partial system measurements susceptible to (possible) biasing attacks. In particular, we assume that the system is not locally observable via the measurements in the direct neighborhood of any agent. First, for performance analysis in the att...\",\n \"Title: Observer-based Control for Vehicle Platooning with a Leader of Varying Velocity\\nYear: 2021\\n\\nAbstract: This paper studies the internal stability and string stability of a vehicle platooning with a varying-velocity leader using a multiple-predecessor following strategy via vehicle-to-vehicle communication. Unlike the common case in which the leader’s velocity is constant and different kinds of PID controllers are implemented, in this case, the fact that the leader has a velocity that varies over tim...\",\n \"Title: A Priority-Based Distributed Channel Access Mechanism for Control over CAN-like Networks\\nYear: 2021\\n\\nAbstract: In this work, we study the distributed channel access problem for multiple subsystems equipped with smart sensors sharing a capacity-limited communication network to perform their control tasks. We propose a fully distributed scheme to use the limited communication resources efficiently with respect to a quadratic cost which reflects the control performance. More specifically, we adopt a priority ...\",\n \"Title: A Survey on Reinforcement Learning-Aided Caching in Heterogeneous Mobile Edge Networks\\nYear: 2022\\n\\nAbstract: Mobile networks experience a tremendous increase in data volume and user density due to the massive number of coexisting users and devices. An efficient technique to alleviate this issue is to bring the data closer to the users by exploiting cache-aided edge nodes, such as fixed and mobile access points, and even user devices. Meanwhile, the fusion of machine learning and wireless networks offers new opportunities for network optimization when traditional optimization approaches fail or incur high complexity. Among the various machine learning categories, reinforcement learning provides autonomous operation without relying on large sets of historical data for training. In this survey, reinforcement learning-aided mobile edge caching solutions are presented and classified, based on the networking architecture and optimization target. As sixth generation (6G) networks will be characterized by high heterogeneity, fixed cellular, fog, cooperative, vehicular, and aerial networks are studied. The discussion of these works reveals that there exist reinforcement learning-aided caching schemes with varying complexity that can surpass the performance of conventional policy-based approaches. Finally, several open issues are presented, stimulating further interest in this important research field.\",\n \"Title: Complete Characterization of Gorbunov and Pinsker Nonanticipatory Epsilon Entropy of Multivariate Gaussian Sources: Structural Properties\\nYear: 2022\\n\\nAbstract: This paper derives the optimal test channel distribution and the complete characterization of the classical Gorbunov and Pinsker (1973), Gorbunov and Pinsker (1974) nonanticipatory epsilon entropy of multivariate Gaussian Markov sources with square-error fidelity, which remained an open problem since 1974. The paper also formulates a state dependent nonanticipatory epsilon entropy, in which past r...\",\n \"Title: Consensus-Based Distributed Estimation in the Presence of Heterogeneous, Time-Invariant Delays\\nYear: 2022\\n\\nAbstract: Classical distributed estimation scenarios typically assume timely and reliable exchanges of information over the sensor network. This letter, in contrast, considers single time-scale distributed estimation via a sensor network subject to transmission time-delays. The proposed discrete-time networked estimator consists of two steps: (i) consensus on (delayed) a-priori estimates, and (ii) measurement update. The sensors only share their a-priori estimates with their out-neighbors over (possibly) time-delayed transmission links. The delays are assumed to be fixed over time, heterogeneous, and known. We assume distributed observability instead of local observability, which significantly reduces the communication/sensing loads on sensors. Using the notions of augmented matrices and the Kronecker product, the convergence of the proposed estimator over strongly-connected networks is proved for a specific upper-bound on the time-delay.\",\n \"Title: Distributed Alternating Direction Method of Multipliers using Finite-Time Exact Ratio Consensus in Digraphs\\nYear: 2021\\n\\nAbstract: In this work, we consider the distributed optimization problem in which each node has its own convex cost function and can communicate directly only with its neighbors, as determined by a directed communication topology (directed graph or digraph). First, we reformulate the optimization problem so that Alternating Direction Method of Multipliers (ADMM) can be utilized. Then, we propose an algorithm, herein called Distributed Alternating Direction Method of Multipliers using Finite-Time Exact Ratio Consensus (D-ADMM-FTERC), to solve the multi-node convex optimization problem, in which every node performs iterative computations and exchanges information with its neighbors. At every iteration of D-ADMM-FTERC, each node solves a local convex optimization problem for the one of the primal variables and utilizes a finite-time exact consensus protocol to obtain the optimal value of the other variable, since the cost function for the second primal variable is not decomposable. If the individual cost functions are convex and not-necessarily differentiable, the proposed algorithm converges at a rate of O(1/k), where k is the iteration counter. The efficacy of D-ADMM-FTERC is demonstrated via a distributed least square optimization example. Additionally, comparisons with other state-of-the-art algorithms are provided on both small and large scale systems showing the superior precision and time-efficient performance of D-ADMM-FTERC.\",\n \"Title: Bandit-Based Power Control in Full-Duplex Cooperative Relay Networks With Strict-Sense Stationary and Non-Stationary Wireless Communication Channels\\nYear: 2022\\n\\nAbstract: Full-duplex relaying is an enabling technique of sixth generation (6G) mobile networks, promising tremendous rate and spectral efficiency gains. In order to improve the performance of full-duplex communications, power control is a viable way of avoiding excessive loop interference at the relay. Unfortunately, power control requires channel state information of source-relay, relay-destination and loop interference channels, thus resulting in increased overheads. Aiming to offer a low-complexity alternative for power control in such networks, we adopt reward-based learning in the sense of multi-armed bandits. More specifically, we present bandit-based power control, relying on acknowledgements/negative-acknowledgements observations by the relay. Our distributed algorithms avoid channel state information acquisition and exchange, and can alleviate the impact of outdated channel state information. Two cases are examined regarding the channel statistics of the wireless network, namely, strict-sense stationary and non-stationary channels. For the latter, a sliding window approach is adopted to further improve the performance. Performance evaluation highlights a performance-complexity trade-off, compared to optimal power control with full channel knowledge and significant gains over cases considering channel estimation and feedback overheads, outdated channel knowledge, no power control and random power level selection. Finally, it is shown that the sliding-window bandit-based algorithm provides improved performance in non-stationary settings by efficiently adapting to abrupt changes of the wireless channels.\",\n \"Title: Information freshness and packet drop rate interplay in a two-user multi-access channel\\nYear: 2022\\n\\nAbstract: In this work, we combine the two notions of timely delivery of information to study their interplay; namely, deadline-constrained packet delivery due to latency constraints and freshness of information. More specifically, we consider a two-user multiple access setup with random access, in which user 1 is a wireless device with a buffer and has external bursty traffic which is deadline-constrained, while user 2 monitors a sensor and transmits status updates to the destination. We provide analytical expressions for the throughput and drop probability of user 1. For user 2, we derive in closed form the age of information distribution, the average age of information (AoI), and the probability the AoI to be larger than a certain value for each time slot. The relations reveal a trade-off between the average AoI of user 2 and the drop rate of user 1: the lower the average AoI, the higher the drop rate, and vice versa. Simulations corroborate the validity of our theoretical results.\",\n \"Title: Finite-Time and Adaptive Observer based Fully Distributed Synchronization of Heterogeneous Linear Systems with Delays\\nYear: 2022\\n\\nAbstract: In this paper, the output synchronization (OS) problem of heterogeneous linear multi-agent systems (MASs) with input delays is addressed. Agents may have different state dimensions and different dynamics. A finite-time observer (FO) is firstly proposed to estimate the uncertain leader's system dynamics. Then, based on the above FO, an adaptive observer (AO) is designed to estimate leader's state information. Thirdly, a novel state predictor is proposed to tackle the input delay effect based on the above AO and output regulation theory. After that, a third observer is designed to estimate the above state predictor so that the controller can be implemented in reality. The stability analysis is performed via Lyapunov stability theory with sufficient conditions derived in terms of an algebraic Riccati equation. The main achievement of this work is the construction of an observer-based fully distributed controller (FDC) which relies on local information only and does not require knowledge of the leader's dynamics or global graph information. As a result, such an approach can be implemented to large-scale systems. Finally, the effectiveness of the proposed FDC is verified via simulations and the influence of the system's graph structure on the convergence rate of the FDC is discussed.\",\n \"Title: Towards Establishing String Stability Conditions For Heterogeneous Vehicle Platoons Under the MPF Topology\\nYear: 2022\\n\\nAbstract: Enhancing the adaptive cruise control (ACC) functionality with wireless communication links, in addition to sensors such as radars and/or lidars, cooperative adaptive cruise control (CACC) is facilitated. CACC enables driving at small intervehicle distances, forming a vehicle platoon system, while maintaining string stability (i.e., the disturbance is attenuated along the vehicle string). While string stability is a necessary requirement for the design of vehicle platoons, most of the works are limited to homogeneous vehicles or platoons with a single heterogeneity, which is not often the case in reality. In this work, we make an attempt to provide sufficient conditions for string stability for a very general case of heterogeneous vehicle platoons under the multiple-predecessor following (MPF) topology. More specifically, we focus on the following forms of heterogeneity: different parasitic lags, different time headways, different controller parameters and different communication time delays. First, we obtain sufficient conditions for string stability for the general case. Homogeneous vehicle platoons or platoons with a single heterogeneity constitute special cases. Since providing closed-form expressions for the general case is not feasible, we analyze some simpler, yet practical, cases. In particular, we allow the time headway and the controllers to be identical (this can be part of the design of the vehicle platoons) and we consider the case in which parasitic lags and communication time delays can be different. Case studies are considered in simulations in order to give more insights and limitations of our results.\",\n \"Title: Fast-Convergent Anytime-Feasible Dynamics for Distributed Allocation of Resources Over Switching Sparse Networks with Quantized Communication Links\\nYear: 2022\\n\\nAbstract: This paper proposes anytime feasible networked dynamics to solve resource allocation problems over time-varying multi-agent networks. The state of agents represents the assigned resources while their total (equal to demand) is constant. The idea is to optimally allocate the resources among the group of agents by minimizing the overall cost subject to fixed sum of resources. Each agent's information is local and restricted to its own state, cost function, and the ones from its immediate neighbors. This work provides a fast convergent solution (compared to linear dynamics) while considering more-relaxed uniform network connectivity and (logarithmic) quantized communications among agents. The proposed dynamics reaches optimal solution over switching (sparsely-connected) undirected networks as far as their union over some bounded non-overlapping time-intervals has a spanning tree. Moreover, we prove anytime-feasibility of the solution, uniqueness, and convergence to the optimal value irrespective of the specific nonlinearity in the proposed dynamics. Such general proof analysis applies to many similar 1st-order allocation dynamics subject to strongly sign-preserving nonlinearities, e.g., actuator saturation in generator coordination. Further, anytime feasibility (despite the nonlinearities) ensures that our solution satisfies the fixed-sum resources constraint at all times.\",\n \"Title: Distributed Anomaly Detection and Estimation over Sensor Networks: Observational-Equivalence and <tex>$Q$</tex>-Redundant Observer Design\\nYear: 2022\\n\\nAbstract: In this paper, we study stateless and stateful physics-based anomaly detection scenarios via distributed estimation over sensor networks. In the stateful case, the detector keeps track of the sensor residuals (i.e., the difference of estimated and true outputs) and reports an alarm if certain statistics of the recorded residuals deviate over a predefined threshold, e.g., \\n<tex xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">$\\\\chi^{2}$</tex>\\n (Chi-square) detector. Instead, only instantaneous deviation of the residuals raises the alarm in the stateless case without considering the history of the sensor outputs and estimation data. Given (approximate) false-alarm rate for both cases, we propose a probabilistic threshold design based on the noise statistics. We show by simulation that increasing the window length in the stateful case may not necessarily reduce the false-alarm rate. On the other hand, it adds unwanted delay to raise the alarm. The distributed aspect of the proposed detection algorithm enables local isolation of the faulty sensors with possible recovery solutions by adding redundant observationally-equivalent sensors. We, then, offer a mechanism to design \\n<tex xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">$Q$</tex>\\n-redundant distributed observers, robust to failure (or removal) of up to \\n<tex xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">$Q$</tex>\\n sensors over the network.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":77,"string":"77"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13367,"string":"13,367"}}},{"rowIdx":13368,"cells":{"question_id":{"kind":"string","value":"Venkatram Vishwanath"},"question":{"kind":"string","value":"Generate an abstract for the title \"Comparison of Vendor Supplied Environmental Data Collection Mechanisms\" using the following items: high performance computing, hardware components, environmental aspects, data comparison, future features."},"answer":{"kind":"string","value":"The high performance computing landscape is filled with diverse hardware components. A large part of understanding how these components compare to others is by looking at the various environmental aspects of these devices such as power consumption, temperature, etc. Thankfully, vendors of these various pieces of hardware have supported this by providing mechanisms to obtain this data. However, differences not only in the way this data is obtained but also the data which is provided is common between products. In this paper, we take a comprehensive look at the data which is available for the most common pieces of today's HPC landscape, as well as how this data is obtained and how accurate it is. Having surveyed these components, we compare and contrast them noting key differences as well as providing insight into what features future components should have."},"correct_answer":{"kind":"string","value":"The high performance computing landscape is filled with diverse hardware components. A large part of understanding how these components compare to others is by looking at the various environmental aspects of these devices such as power consumption, temperature, etc. Thankfully, vendors of these various pieces of hardware have supported this by providing mechanisms to obtain this data. However, differences not only in the way this data is obtained but also the data which is provided is common between products. In this paper, we take a comprehensive look at the data which is available for the most common pieces of today's HPC landscape, as well as how this data is obtained and how accurate it is. Having surveyed these components, we compare and contrast them noting key differences as well as providing insight into what features future components should have."},"documents":{"kind":"list like","value":["Title: ALCF MPI Benchmarks: Understanding Machine-Specific Communication Behavior\nYear: 2012\n\nAbstract: As systems grow larger and computation is further spread across nodes, efficient data communication is becoming increasingly important to achieve high throughput and low power consumption for high performance computing systems. However, communication efficacy not only depends on application-specific communication patterns, but also on machine-specific communication subsystems, node architectures, and even the runtime communication libraries. In fact, different hardware systems lead to different tradeoffs with respect to communication mechanisms, which can impact the choice of application implementations. We present a set of MPI-based benchmarks to better understand the communication behavior of the hardware systems and guide the performance tuning of scientific applications. We further apply these benchmarks to three clusters and present several interesting lessons from our experience.","Title: Specification and Verification of LambdaRAM: A Wide-area Distributed Cache for High Performance Computing\nYear: 2008\n\nAbstract: LambdaRAM is a high-performance, multidimensional, wide-area, distributed cache that takes advantage of massively available memory from multiple clusters interconnected by ultra high-speed networking to provide data-intensive scientific applications with rapid access to both local and remote data without suffering the latency bottlenecks often associated with large storage systems and wide-area data access. LambdaRAM has been demonstrated to yield significant performance speed-ups for Geophysical and Bioscience applications accessing extremely large datasets. Currently, LambdaRAM is being integrated by NASA for the Modelling, Analysis and Prediction (MAP) Program applications to study tropical cyclones. Formal verification of LambdaRAM is important to NASA to ensure that LambdaRAM operates reliably in real-time mission critical deployments. We present ourpreliminary steps towardsfullformal verification of LambdaRAM. We first give an abstract description of the system and then verify several of its properties. Most of the proofs are accomplished by automatic techniques, while some require deductive steps.","Title: Accelerating I/O Forwarding in IBM Blue Gene/P Systems\nYear: 2010\n\nAbstract: Current leadership-class machines suffer from a significant imbalance between their computational power and their I/O bandwidth. I/O forwarding is a paradigm that attempts to bridge the increasing performance and scalability gap between the compute and I/O components of leadership-class machines to meet the requirements of data-intensive applications by shipping I/O calls from compute nodes to dedicated I/O nodes. I/O forwarding is a critical component of the I/O subsystem of the IBM Blue Gene/P supercomputer currently deployed at several leadership computing facilities. In this paper, we evaluate the performance of the existing I/O forwarding mechanisms for BG/P and identify the performance bottlenecks in the current design. We augment the I/O forwarding with two approaches: I/O scheduling using a work-queue model and asynchronous data staging. We evaluate the efficacy of our approaches using microbenchmarks and application-level benchmarks on leadership class systems.","Title: Job Coscheduling on Coupled High-End Computing Systems\nYear: 2011\n\nAbstract: Supercomputer centers often deploy large-scale computing systems together with an associated data analysis or visualization system. In this paper, we propose a co scheduling mechanism, providing the ability to coordinate execution between jobs on different systems. The mechanism is built on top of a lightweight protocol for coordination between policy domains without manual intervention. We have evaluated this system using real job traces from Intrepid and Eureka, the production Blue Gene/P and data analysis systems, respectively, deployed at Argonne National Laboratory. Our experimental results quantify the costs of co scheduling and demonstrate that co scheduling can be achieved with limited impact on system performance under varying workloads.","Title: The OptIPortal, a scalable visualization, storage, and computing interface device for the OptiPuter\nYear: 2009\n\nAbstract: The OptIPortal is a tiled display that is the visual interface to the OptIPuter, a global-scale computing system tied together by tens of gigabits of networking. The main point of the OptIPuter project is to examine a ''future'' in which networking is not a bottleneck to local, regional, national and international computing. OptIPortals are designed to allow collaborative sharing over 1-10 gigabit/second networks of extremely high-resolution graphic output, as well as video streams. OptIPortals typically consist of an array of 4 to 70 LCD display panels (either 2-megapixel or 4-megapixel each), driven by an appropriately sized cluster of PCs, with optimized graphics processors and network interface cards. Rather than exist as one-of-a-kind laboratory prototypes, OptIPortals are designed to be openly and widely replicated, balancing the state of the art of PCs, graphic processing, networks, servers, software, middleware, and user interfaces, and installed in the context of a laboratory or office conference room. Discussed in detail are the design decisions made to achieve a replicable tiled display that can be built by computational science researchers in various disciplines.","Title: Electronic poster: co-visualization of full data and in situ data extracts from unstructured grid cfd at 160k cores\nYear: 2011\n\nAbstract: Scalability and time-to-solution studies have historically been focused on the size of the problem and run time. We consider a more strict definition of \"solution\" whereby a live data analysis (co-visualization of either the full data or in situ data extracts) provides continuous and reconfigurable insight into massively parallel simulations. Specifically, we used the Argonne Leadership Class Facility's (ALCF) BlueGene/P machine with 163,840 cores tightly linked through a high-speed network to 100 visualization nodes that share 800 cores and 200 GPUs. Three meshes with respectively 52M, 416M and 3.3B elements discretize the flow over a full swept wing with an unsteady synthetic jet to evaluate time-to-solution plus insight. On the full machine, the 416M element mesh takes about 2 seconds per flow solve step including the extraction and rendering of a slice or a contour, slowing currently the simulation by only 10 and 15% respectively. The 3.3B element case proved scalable at about 15 seconds per time step, whereas PHASTA's strong scaling could compress the time-to-solution for the 52M element case enough to allow the rendering of one frame (slice or contour) every 0.7 second, paving the way for interactive simulation and simulation steering on massively parallel systems1.","Title: Fast Multiresolution Reads of Massive Simulation Datasets\nYear: 2014\n\nAbstract: Today's massively parallel simulation codes can produce output ranging up to many terabytes of data. Utilizing this data to support scientific inquiry requires analysis and visualization, yet the sheer size of the data makes it cumbersome or impossible to read without computational resources similar to the original simulation. We identify two broad classes of problems for reading data and present effective solutions for both. The first class of data reads depends on user requirements and available resources. Tasks such as visualization and user-guided analysis may be accomplished using only a subset of variables with a restricted spatial extent at a reduced resolution. The other class of reads requires full resolution multivariate data to be loaded, for example to restart a simulation. We show that utilizing the hierarchical multiresolution IDX data format enables scalable and efficient serial and parallel read access on a variety of hardware from supercomputers down to portable devices. We demonstrate interactive view-dependent visualization and analysis of massive scientific datasets using low-power commodity hardware, and we compare read performance with other parallel file formats for both full and partial resolution data.","Title: Scalable in situ scientific data encoding for analytical query processing\nYear: 2013\n\nAbstract: The process of scientific data analysis in high-performance computing environments has been evolving along with the advancement of computing capabilities. With the onset of exascale computing, the increasing gap between compute performance and I/O bandwidth has rendered the traditional method of post-simulation processing a tedious process. Despite the challenges due to increased data production, there exists an opportunity to benefit from \"cheap\" computing power to perform query-driven exploration and visualization during simulation time. To accelerate such analyses, applications traditionally augment raw data with large indexes, post-simulation, which are then repeatedly utilized for data exploration. However, the generation of current state-of-the-art indexes involve a compute- and memory-intensive processing, thus rendering them inapplicable in an in situ context. In this paper we propose DIRAQ, a parallel in situ, in network data encoding and reorganization technique that enables the transformation of simulation output into a query-efficient form, with negligible runtime overhead to the simulation run. DIRAQ begins with an effective core-local, precision-based encoding approach, which incorporates an embedded compressed index that is 3 -- 6x smaller than current state-of-the-art indexing schemes. DIRAQ then applies an in network index merging strategy, enabling the creation of aggregated indexes ideally suited for spatial-context querying that speed up query responses by up to 10x versus alternative techniques. We also employ a novel aggregation strategy that is topology-, data-, and memory-aware, resulting in efficient I/O and yielding overall end-to-end encoding and I/O time that is less than that required to write the raw data with MPI collective I/O.","Title: PIDX: Efficient Parallel I/O for Multi-resolution Multi-dimensional Scientific Datasets\nYear: 2011\n\nAbstract: The IDX data format provides efficient, cache oblivious, and progressive access to large-scale scientific datasets by storing the data in a hierarchical Z (HZ) order. Data stored in IDX format can be visualized in an interactive environment allowing for meaningful explorations with minimal resources. This technology enables real-time, interactive visualization and analysis of large datasets on a variety of systems ranging from desktops and laptop computers to portable devices such as iPhones/iPads and over the web. While the existing ViSUS API for writing IDX data is serial, there are obvious advantages of applying the IDX format to the output of large scale scientific simulations. We have therefore developed PIDX - a parallel API for writing data in an IDX format. With PIDX it is now possible to generate IDX datasets directly from large scale scientific simulations with the added advantage of real-time monitoring and visualization of the generated data. In this paper, we provide an overview of the IDX file format and how it is generated using PIDX. We then present a data model description and a novel aggregation strategy to enhance the scalability of the PIDX library. The S3D combustion application is used as an example to demonstrate the efficacy of PIDX for a real-world scientific simulation. S3D is used for fundamental studies of turbulent combustion requiring exceptionally high fidelity simulations. PIDX achieves up to 18 GiB/s I/O throughput at 8,192 processes for S3D to write data out in the IDX format. This allows for interactive analysis and visualization of S3D data, thus, enabling in situ analysis of S3D simulation.","Title: Dataflow-driven GPU performance projection for multi-kernel transformations\nYear: 2012\n\nAbstract: Applications often have a sequence of parallel operations to be offloaded to graphics processors; each operation can become an individual GPU kernel. Developers typically explore a variety of transformations for each kernel. Furthermore, it is well known that efficient data management is critical in achieving high GPU performance and that \"fusing\" multiple kernels into one may greatly improve data locality. Doing so, however, requires transformations across multiple, potentially nested, parallel loops; at the same time, the original code semantics and data dependency must be preserved. Since each kernel may have distinct data access patterns, their combined dataflow can be nontrivial. As a result, the complexity of multi-kernel transformations often leads to significant effort with no guarantee of performance benefits. This paper proposes a dataflow-driven analytical framework to project GPU performance for a sequence of parallel operations. Users need only provide CPU code skeletons for a sequence of parallel loops. The framework can then automatically identify opportunities for multi-kernel transformations and data management. It is also able to project the overall performance without implementing GPU code or using physical hardware.","Title: Topology-aware data movement and staging for I/O acceleration on Blue Gene/P supercomputing systems\nYear: 2011\n\nAbstract: There is growing concern that I/O systems will be hard pressed to satisfy the requirements of future leadership-class machines. Even current machines are found to be I/O bound for some applications. In this paper, we identify existing performance bottlenecks in data movement for I/O on the IBM Blue Gene/P (BG/P) supercomputer currently deployed at several leadership computing facilities. We improve the I/O performance by exploiting the network topology of BG/P for collective I/O, leveraging data semantics of applications and incorporating asynchronous data staging. We demonstrate the efficacy of our approaches for synthetic benchmark experiments and for application-level benchmarks at scale on leadership computing systems.","Title: Accelerating tropical cyclone analysis using LambdaRAM, a distributed data cache over wide-area ultra-fast networks\nYear: 2009\n\nAbstract: Data-intensive scientific applications require rapid access to local and geographically distributed data, however, there are significant I/O latency bottlenecks associated with storage systems and wide-area networking. LambdaRAM is a high-performance, multi-dimensional, distributed cache, that takes advantage of memory from multiple clusters interconnected by ultra-high-speed networking, to provide applications with rapid access to both local and remote data. It mitigates latency bottlenecks by employing proactive latency-mitigation heuristics based on an application's access patterns. We present results using LambdaRAM to rapidly stride through remote multi-dimensional NASA Modeling, Analysis and Prediction (MAP) 2006 project datasets, based on time and geographical coordinates, to compute wind shear for cyclone and hurricane and tropical cyclone analysis. Our current experiments have demonstrated up to a 20-fold speedup in the computation of wind shear with LambdaRAM.","Title: Early Experience on the Blue Gene/Q Supercomputing System\nYear: 2013\n\nAbstract: The Argonne Leadership Computing Facility (ALCF) is home to Mira, a10 PF Blue Gene/Q (BG/Q) system. The BG/Q system is the third generation in Blue Gene architecture from IBM and like its predecessors combines system-on-chip technology with a proprietary interconnect (5-D torus). Each compute node has 16 augmented PowerPCA2 processor cores with support for simultaneous multithreading, 4-wide double precision SIMD, and different data prefetchingmechanisms. Mira offers several new opportunities for tuning and scaling scientific applications. This paper discusses our early experience with a subset of micro-benchmarks, MPI benchmarks, and a variety of science and engineering applications running at ALCF. Both performance and power are studied and results on BG/Q is compared with its predecessor BG/P. Several lessons gleaned from tuning applications on the BG/Q architecture for better performance and scalability are shared.","Title: Modeling early galaxies using radiation hydrodynamics\nYear: 2011\n\nAbstract: This simulation uses a flux-limited diffusion solver to explore the radiation hydrodynamics of early galaxies, in particular, the ionizing radiation created by Population III stars. At the time of this rendering, the simulation has evolved to a redshift of 3.5. The simulation volume is 11.2 comoving megaparsecs, and has a uniform grid of 10243 cells, with over 1 billion dark matter and star particles. This animation shows a combined view of the baryon density, dark matter density, radiation energy and emissivity from this simulation. The multi-variate rendering is particularly useful because is shows both the baryonic matter (\"normal\") and dark matter, and the pressure and temperature variables are properties of only the baryonic matter. Visible in the gas density are \"bubbles\", or shells, created by the radiation feedback from young stars. Seeing the bubbles from feedback provides confirmation of the physics model implemented. Features such as these are difficult to identify algorithmically, but easily found when viewing the visualization","Title: GROPHECY: GPU performance projection from CPU code skeletons\nYear: 2011\n\nAbstract: We propose GROPHECY, a GPU performance projection frame work that can estimate the performance benefit of GPU acceleration without actual GPU programming or hardware. Users need only to skeletonize pieces of CPU code that are targets for GPU acceleration. Code skeletons are automatically transformed in various ways to mimic tuned GPU codes with characteristics resembling real implementations. The synthesized characteristics are used by an existing analytical model to project GPU performance. The cost and benefit of GPU development can then be estimated according to the transformed code skeleton that yields the best projected performance. With GROPHECY, users can leap toward GPU acceleration only when the cost-benefit makes sense. The framework is validated using kernel benchmarks and data-parallel codes in legacy scientific applications. The measured performance of manually tuned codes deviates from the projected performance by 17% in geometric mean.","Title: Poster: Evaluating Communication Performance in BlueGene/Q and Cray XE6 Supercomputers\nYear: 2012\n\nAbstract: Evaluation of the communication performance in supercomputers Blue Gene/Q and Cray XE6 using MPI and lower level libraries are presented. MPI is widely used for to its simplicity, portability and straightforwardness, however it also introduces overhead that degrades communication performance. Some applications with performance constraints cannot tolerate that degradation. Recent supercomputers such as the Blue Gene/Q and CrayXE provide lower level communications libraries such as PAMI (Parallel Active Message Interface) and uGNI (User Generic Network Interface). Our experiments show that with different communications modes: one-sided, two-sided, inter-node, intra-node, we can achieve higher performance with certain message sizes. These results will enable us to develop a light-weight API for GLEAN which is a framework for I/O acceleration and in situ analysis, to get improved performance on these systems.","Title: Accelerating Data Movement Leveraging End-System and Network Parallelism\nYear: 2012\n\nAbstract: Data volumes produced by simulation, experimental and observational science is rapidly increasing. This data needs to be moved from its source to another resource for analysis, visualization and archival purposes. The destination resource could be either local or remote. The data intensive science is critically dependent upon the high-performance parallel file and storage end systems to read/write and high-speed networks to move their enormous data between local and remote computing and storage facilities. 100 Gigabit per second networks such as DOE's Advanced Network Initiative (ANI), Internet2's 100G network represent a major step forward in wide area network performance. Effective utilization of these networks requires substantial and pervasive parallelism, at the file system, end system, and network levels. Additional obstacles such as heterogeneity and time-varying conditions of network and end system arise that, if not adequately addressed, will render high performance storage and network systems extremely under-performed. In this paper, we propose a data movement system that dynamically and adaptively adjusts end systems and networks parallelisms in response to changing conditions of end systems and networks to sustain high-throughput for data transfers. We evaluate our system in multiple settings and show that (1) in a homogeneous configuration, the design can achieve better throughput for light and medium workload than GridFTP and achieve comparable throughput for heavy workload, (2) and in a heterogeneous configuration, the design can achieve several factors higher throughput for all workloads than GridFTP.","Title: The Rails Toolkit - Enabling End-System Topology-Aware High End Computing\nYear: 2008\n\nAbstract: We present a novel rails approach so that future e-Science applications can effectively exploit future system architectures, including multi-core and many-core architectures, multiple network cards, multiple graphical processing units and hybrid hierarchical memory architectures. We define \"rail\" as the co-scheduling of two or more of these resources. This approach enables creation of parallel multi-rails through every aspect of an end system: from processing on the multi- and many cores, to generation of multiple data flows and streaming over multi-lane network interface card (NIC) connected via a parallel interconnect. We describe a novel open-source multi-rail toolkit and the evaluation of end-system parameters that impact the efficiency of such multi-rail systems, including Interrupt, Memory, Thread and Core Affinities -- key properties for achieving scalable performance.","Title: The global lambda visualization facility: an international ultra-high-definition wide-area visualization collaboratory\nYear: 2006\n\nAbstract: The research outlined in this paper marks an initial global cooperative effort between visualization and collaboration researchers to build a persistent virtual visualization facility linked by ultra-high-speed optical networks. The goal is to enable the comprehensive and synergistic research and development of the necessary hardware, software and interaction techniques to realize the next generation of end-user tools for scientists to collaborate on the global Lambda Grid. This paper outlines some of the visualization research projects that were demonstrated at the iGrid 2005 workshop in San Diego, California.","Title: Characterization And Understanding Machine-Specific Interconnects\nYear: 2013\n\nAbstract: The use of efficient communication patterns is becoming increasingly important to utilize high concurrency and achieve high throughput and low latency of modern high-performance supercomputers. Efficacy is not only dictated by an application communication pattern, but also driven by the interconnect properties, the node architecture, and the quality of runtime communication libraries. Different systems require different tradeoffs with respect to communication mechanisms, which can impact the choice of application implementations. We use the in-house MPI benchmark suite to study the communication behavior of the interconnects and guide the performance tuning of scientific applications. We report the results of our investigation of four supercomputer systems located at ALCF, and present lessons learned from our experience.","Title: Proactive Support for Large-Scale Data Exploration\nYear: 2013\n\nAbstract: Computational science is generating increasingly unwieldy datasets created by complex and high-resolution simulations of physical, social, and economic systems. Traditional post processing of such large datasets requires high bandwidth to large storage resources. In situ processing approaches can reduce I/O requirements but steal processing cycles from the simulation and forsake interactive data exploration. The Fusion project aims to develop a new approach for exploring large-scale scientific datasets wherein the system actively assists the user in the data exploration process. A key component of the system is a software assistant that evaluates the stated and implied analysis goals of the scientist, observes the environment, models and proposes actions to be taken, and orchestrates the generation of analysis and visualization products for the user. These products are managed and made available to the scientist through an interactive space consisting of a database and a visual interface. The scientist sifts through and explores the available analysis products while indicating preferences that are translated into goals, completing the feedback loop that steers the assistant in its future actions.","Title: Abstract: Evaluating Communication Performance in BlueGene/Q and Cray XE6 Supercomputers\nYear: 2012\n\nAbstract: Summary form only given. Evaluation of the communication performance in supercomputers Blue Gene/Q and Cray XE6 using MPI and lower level libraries are presented. MPI is widely used for to its simplicity, portability and straightforwardness, however it also introduces overhead that degrades communication performance. Some applications with performance constraints cannot tolerate that degradation. Recent supercomputers such as the Blue Gene/Q and CrayXE provide lower level communications libraries such as PAMI (Parallel Active Message Interface) and uGNI (User Generic Network Interface). Our experiments show that with different communications modes: one-sided, two-sided, inter-node, intra-node we can always achieve higher performance with certain message sizes. These results will enable us to develop a GLEAN- light-weight API, which can be called directly from applications without passing through MPI to reduce/remove overhead.","Title: LambdaBridge: A Scalable Architecture for Future Generation Terabit Applications\nYear: 2006\n\nAbstract: LambdaGrid applications as typified by data-intensive collaborative visualization are likely to be the first users of terabit-level networking. This paper features a main enabler of collaborative visualization over LambdaGrid, the Scalable Adaptive Graphics Environment (SAGE) in particular, and anticipates the future needs of LambdaGrid applications in general. We present a scalable architecture called LambdaBridge to 'bridge' LambdaGrid applications with the terabit optical core networks. LambdaBridge will provision and control predictable- performance networks for end-systems (i.e. Grid clusters) using on-demand lambda/VLAN provisioning and end-system traffic shaping. The chief contribution of LambdaBridge is a deep understanding of how to synergistically bridge provisionable networks, end-systems, and future generation distributed terabit applications. This paper also introduces Scalable Visualcasting - a multicasting service for LambdaGrid that incorporates IP multicasting and optical multicasting.","Title: Measuring Power Consumption on IBM Blue Gene/Q\nYear: 2013\n\nAbstract: In addition to pushing what is possible computationally, state-of-the-art supercomputers are also pushing what is acceptable in terms of power consumption. Despite hardware manufacturers researching and developing efficient system components (e.g., processor, memory, etc.), the power consumption of a complete system remains an understudied research area. Because of the complexity and unpredictable workloads of these systems, estimating the power consumption of a full system is a nontrivial task.In this paper, we provide system-level power usage and temperature analysis of early access to Argonne's latest generation of IBM Blue Gene supercomputers, the Mira Blue Gene/Q system. The analysis is provided from the point of view of jobs running on the system. We describe the important implications these system level measurements have as well as the challenges they present. Using profiling code on benchmarks, we will also look at the new tools this latest generation of supercomputer provides and gauge their usefulness and how well they match up against the environmental data.","Title: Model-Driven Multisite Workflow Scheduling\nYear: 2013\n\nAbstract: Workflows continue to play an important role in expressing and deploying scientific applications. In recent years, a wide variety of computational sites have emerged with shared access to users. A user may not be able to complete a complex workflow at a single site. It is thus beneficial to run different tasks of a workflow on different sites. For such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources at multiple sites so that the workload is balanced among sites and the overhead is minimized in data transfer. The key challenge is that the data transfer rate among sites varies based on the network capacity and load. We propose a workflow scheduling technique that tackles the multi-site task distribution challenge by using data movement performance modeling. We applied this technique to schedule an earth observation science workflow over three sites. Executed via the Swift parallel scripting paradigm, we augmented its default schedule and improved the time-to-completion by up to 52%.","Title: Ar-pin/pdc: flexible advance reservation of intradomain and interdomain lightpaths\nYear: 2006\n\nAbstract: Grid is a computing architecture that consists of distributed clusters of computers interconnected by a network. Grid computing is used in a variety of data and compute-intensive scientific domains such as bioscience, nanotechnology, geoscience, high-energy physics. To facilitate the transportation of enormous (e.g. terabyte-sized) data-sets between Grid clusters, a new type of Grid computing architecture, called the LambdaGrid, has emerged. LambdaGrids are Grids that are interconnected by ultra-high-speed networks that can be directly controlled by applications. Typically the unit of control is a light path (often called a Lambda) in an optical network. In order for data-intensive applications to function efficiently, they need to be able to reserve enough bandwidth, through the allocation of these light paths. This thesis focuses on the problem of efficient scheduling of light paths between Grid clusters. Prior approaches use rigid scheduling schemes- i.e. resources are scheduled in terms of when the resources are needed and for how long. This thesis will show that contrary to obvious expectations, a flexible advance scheduling model can provide better overall resource utilization and user experience than a rigid scheduling scheme. In this thesis I propose a Flexible Advance Reservation Model (FARM) and describe how to apply this model to the cross-domain lightpath reservation problem by incorporating Routing and Wavelength Assignment algorithms. Next, I present the architecture, implementation and services of a coordinated Interdomain and Intradomain optical control plane called AR-PIN/PDC, which is capable of flexible advance reservations, and provides web services. The simulation results show that by relaxing the reservation time constraint, the acceptance rate and resource utilization can be improved dramatically. Through simulations, I also analyze the impact of advance reservations on immediate reservations and conclude that both AR and IR requests need admission control algorithms in order to let both types of reservations coexist and use resource properly. The AR-PIN/PDC software has been deployed in an international photonic testbed consisting of four domains. Over the testbed, I measure the components of end-to-end signaling latency during inter-domain reservation and claim processes. The results show that the major latency component during claim processes is the optical switching time and domain level parallelism can effectively reduce the claim latency. And the time slot granularity is the major factor affecting the reservation latency.","Title: Application power profiling on IBM Blue Gene/Q.\nYear: 2013\n\nAbstract: We describe our power profiling library called MonEQ, built on the IBM provided API.We integrate MonEQ into several benchmarks to show the data it produces.Applications have different power profiles based on usage of domains in node.There is no difference in power consumption in network for a given network topology.Scale can reduce power consumption but is far less important than execution time. The power consumption of state of the art supercomputers, because of their complexity and unpredictable workloads, is extremely difficult to estimate. Accurate and precise results, as are now possible with the latest generation of IBM Blue Gene/Q, are therefore a welcome addition to the landscape. Only recently have end users been afforded the ability to access the power consumption of their applications. However, just because it's possible for end users to obtain this data does not mean it's a trivial task. This emergence of new data is therefore not only understudied, but also not fully understood.In this paper, we describe our open source power profiling library called MonEQ, built on the IBM provided Environmental Monitoring (EMON) API. We show that it's lightweight, has extremely low overhead, is incredibly flexible, and has advanced features which end users can take advantage. We then integrate MonEQ into several benchmarks and show the data it produces and what analysis of this data can teach us. Going one step further we also describe how seemingly simple changes in scale or network topology can have dramatic effects on power consumption. To this end, previously well understood applications will now have new facets of potential analysis.","Title: The first functional demonstration of optical virtual concatenation as a technique for achieving terabit networking\nYear: 2006\n\nAbstract: The optical virtual concatenation (OVC) function of The Terabit LAN was demonstrated for the first time at the iGrid 2005 workshop in San Diego, California. The TERAbit-LAN establishes a lambda group path (LGP) for an application where the number of lambdas/L2 connections in a LGP can be specified by the application. Each LGP is logically treated as one end-to-end optical path, so during parallel transport, the LGP channels have no relative latency deviation. However, optical path diversity (e.g. restoration) can cause LGP relative latency deviations and negatively affect quality of service. OVC hardware developed by NTT compensates for relative latency deviations to achieve a virtual bulk transport for the Electronic Visualization Laboratory's (EVL) Scalable Adaptive Graphics Environment application.","Title: Evaluating Power-Monitoring Capabilities on IBM Blue Gene/P and Blue Gene/Q\nYear: 2012\n\nAbstract: Power consumption is becoming a critical factor as we continue our quest toward exascale computing. Yet, actual power utilization of a complete system is an insufficiently studied research area. Estimating the power consumption of a large scale system is a nontrivial task because a large number of components are involved and because power requirements are affected by the (unpredictable) workloads. Clearly needed is a power-monitoring infrastructure that can provide timely and accurate feedback to system developers and application writers so that they can optimize the use of this precious resource. Many existing large-scale installations do feature power-monitoring sensors, however, those are part of environmental- and health monitoring sub systems and were not designed with application level power consumption measurements in mind. In this paper, we evaluate the existing power monitoring of IBM Blue Gene systems, with the goal of understanding what capabilities are available and how they fare with respect to spatial and temporal resolution, accuracy, latency, and other characteristics. We find that with a careful choice of dedicated micro benchmarks, we can obtain meaningful power consumption data even on Blue Gene/P, where the interval between available data points is measured in minutes. We next evaluate the monitoring subsystem on Blue Gene/Q, and are able to study the power characteristics of FPU and memory subsystems of Blue Gene/Q. We find the monitoring subsystem capable of providing second-scale resolution of power data conveniently separated between node components with seven seconds latency. This represents a significant improvement in power monitoring infrastructure, and hope future systems will enable real-time power measurement in order to better understand application behavior at a finer granularity.","Title: Vol-a-Tile - A Tool for Interactive Exploration of Large Volumetric Data on Scalable Tiled Displays\nYear: 2004\n\nAbstract: We present the current state of Vol-a-Tile, an interactive tool for exploring large volumetric data on scalable tiled displays. Vol-a-Tile presents a variety of features employed by scientists at the Scripps Institution of Oceanography on data collected from the Anatomy of a Ridge-Axis Discontinuity seismic experiment. Hardware texture mapping and level-of-detail techniques provide interactivity. A high-performance network protocol is used to connect remote data sources over high-bandwidth photonic networks.","Title: Multi-application inter-tile synchronization on ultra-high-resolution display walls\nYear: 2010\n\nAbstract: Ultra-high-resolution tiled-display walls are typically driven by a cluster of computers. Each computer may drive one or more displays. Synchronization between the computers is necessary to ensure that animated imagery displayed on the wall appears seamless. Most tiled-display middleware systems are designed around the assumption that only a single application instance is running in the tiled display at a time. Therefore synchronization can be achieved with a simple solution such as a networked barrier. When a tiled display has to support multiple applications at the same time, however, the simple networked barrier approach does not scale. In this paper we propose and experimentally validate two synchronization algorithms to achieve low-latency, intertile synchronization for multiple applications with independently varying frame rates. The two-phase algorithm is more generally applicable to various highresolution tiled display systems. The one-phase algorithm provides superior results but requires support for the Network Time Protocol and is more CPU-intensive.","Title: Multi-domain job coscheduling for leadership computing systems\nYear: 2013\n\nAbstract: Current supercomputing centers usually deploy a large-scale compute system together with an associated data analysis or visualization system. Multiple scenarios have driven the demand that some associated jobs co-execute on different machines. We propose a multi-domain coscheduling mechanism, providing the ability to coordinate execution between jobs on multiple resource management domains without manual intervention. We have evaluated our mechanism based on real job traces from Intrepid and Eureka, the production Blue Gene/P system and a cluster with the largest GPU installation, deployed at Argonne National Laboratory. The experimental results show that coscheduling can be achieved with limited impact on system performance under varying workloads.","Title: Scalable Parallel I/O on a Blue Gene/Q Supercomputer Using Compression, Topology-Aware Data Aggregation, and Subfiling\nYear: 2014\n\nAbstract: In this paper, we propose an approach to improving the I/O performance of an IBM Blue Gene/Q supercomputing system using a novel framework that can be integrated into high performance applications. We take advantage of the system's tremendous computing resources and high interconnection bandwidth among compute nodes to efficiently exploit I/O bandwidth. This approach focuses on lossless data compression, topology-aware data movement, and subfiling. The efficacy of this solution is demonstrated using microbenchmarks and an application-level benchmark.","Title: A generic high-performance method for deinterleaving scientific data\nYear: 2013\n\nAbstract: High-performance and energy-efficient data management applications are a necessity for HPC systems due to the extreme scale of data produced by high fidelity scientific simulations that these systems support. Data layout in memory hugely impacts the performance. For better performance, most simulations interleave variables in memory during their calculation phase, but deinterleave the data for subsequent storage and analysis. As a result, efficient data deinterleaving is critical; yet, common deinterleaving methods provide inefficient throughput and energy performance. To address this problem, we propose a deinterleaving method that is high performance, energy efficient, and generic to any data type. To the best of our knowledge, this is the first deinterleaving method that 1) exploits data cache prefetching, 2) reduces memory accesses, and 3) optimizes the use of complete cache line writes. When evaluated against conventional deinterleaving methods on 105 STREAM standard micro-benchmarks, our method always improved throughput and throughput/watt on multi-core systems. In the best case, our deinterleaving method improved throughput up to 26.2x and throughput/watt up to 7.8x.","Title: DIRAQ: scalable in situ data- and resource-aware indexing for optimized query performance\nYear: 2014\n\nAbstract: Scientific data analytics in high-performance computing environments has been evolving along with the advancement of computing capabilities. With the onset of exascale computing, the increasing gap between compute performance and I/O bandwidth has rendered the traditional post-simulation processing a tedious process. Despite the challenges due to increased data production, there exists an opportunity to benefit from \"cheap\" computing power to perform query-driven exploration and visualization during simulation time. To accelerate such analyses, applications traditionally augment, post-simulation, raw data with large indexes, which are then repeatedly utilized for data exploration. However, the generation of current state-of-the-art indexes involves a compute- and memory-intensive processing, thus rendering them inapplicable in an in situ context. In this paper we propose DIRAQ, a parallel in situ , in network data encoding and reorganization technique that enables the transformation of simulation output into a query-efficient form, with negligible runtime overhead to the simulation run. DIRAQ's effective core-local, precision-based encoding approach incorporates an embedded compressed index that is 3---6 $$\\times $$ smaller than current state-of-the-art indexing schemes. Its data-aware index adjustmentation improves performance of group-level index layout creation by up to 35 % and reduces the size of the generated index by up to 27 %. Moreover, DIRAQ's in network index merging strategy enables the creation of aggregated indexes that speed up spatial-context query responses by up to $$10\\times $$ 10 versus alternative techniques. DIRAQ's topology-, data-, and memory-aware aggregation strategy results in efficient I/O and yields overall end-to-end encoding and I/O time that is less than that required to write the raw data with MPI collective I/O.","Title: Large-Scale Simulations of Sky Surveys.\nYear: 2014\n\nAbstract: Large-volume sky surveys have accessed the Universe's vast temporal and spatial expanse via a remarkable set of measurements. Interpretation of these cosmological observations requires large-scale numerical simulation and modeling. Addressing analysis workflow complexity is as important as running the underlying extreme-scale simulations. Here, the authors discuss how the Hardware/Hybrid Accelerated Cosmology Code framework addresses these challenges.","Title: Profiling transport performance for big data transfer over dedicated channels\nYear: 2015\n\nAbstract: The transfer of big data is increasingly supported by dedicated channels in high-performance networks. Transport protocols play a critical role in maximizing the link utilization of such high-speed connections. We propose a Transport Profile Generator (TPG) to characterize and enhance the end-to-end throughput performance of transport protocols. TPG automates the tuning of various transport-related parameters including socket options and protocol-specific configurations, and supports multiple data streams and multiple NIC-to-NIC connections. To instantiate the design of TPG, we use UDT as an example in the implementation and conduct extensive experiments of big data transfer over high-speed network channels to illustrate how existing transport protocols benefit from TPG in optimizing their performance.","Title: Improving Multisite Workflow Performance Using Model-Based Scheduling\nYear: 2014\n\nAbstract: Workflows play an important role in expressing and executing scientific applications. In recent years, a variety of computational sites and resources have emerged, and users often have access to multiple resources that are geographically distributed. These computational sites are heterogeneous in nature and performance of different tasks in a workflow varies from one site to another. Additionally, users typically have a limited resource allocation at each site. In such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources so that the workload is balanced among sites and the overhead is minimized in data transfer. Most existing systems either run the entire workflow in a single site or use naive approaches to distribute the tasks across sites or leave it to the user to optimize the allocation of tasks to distributed resources. This results in a significant loss in productivity for a scientist. In this paper, we propose a multi-site workflow scheduling technique that uses performance models to predict the execution time on different resources and dynamic probes to identify the achievable network throughput between sites. We evaluate our approach using real world applications in a distributed environment using the Swift distributed execution framework and show that our approach improves the execution time by up to 60% compared to the default schedule.","Title: SKOPE: a framework for modeling and exploring workload behavior\nYear: 2014\n\nAbstract: Understanding workload behavior plays an important role in performance studies. The growing complexity of applications and architectures has increased the gap among application developers, performance engineers, and hardware designers. To reduce this gap, we propose SKOPE, a SKeleton framework for Performance Exploration, that produces a descriptive model about the semantic behavior of a workload, which can infer potential transformations and help users understand how workloads may interact with and adapt to emerging hardware. SKOPE models can be shared, annotated, and studied by a community of performance engineers and system designers; they offer readability in the frontend and versatility in the backend. SKOPE can be used for performance analysis, tuning, and projection. We provide two example use cases. First, we project GPU performance from CPU code without GPU programming or accessing the hardware, and are able to automatically explore transformations and the projected best-achievable performance deviates from the measured by 18% on average. Second, we project the multi-node scaling trends of two scientific workloads, and are able to achieve a projection accuracy of 95%.","Title: Toward optimizing disk-to-disk transfer on 100G networks\nYear: 2013\n\nAbstract: The recent emergence of ultra high-speed networks up to 100 Gbps has posed numerous challenges and has led to many investigations on efficient protocols to saturate 100 Gbps links. However, end-to-end data transfers involve many compo-nents, not only protocols, affecting overall transfer performance. These components include a disk I10 subsystem, additional computation associated with data streams, and network adapter capacities. For example, achievable bandwidth by TCP may not be implementable if disk I/O or CPU becomes a bottleneck in end-to-end data transfer. In this paper, we first model all the system components involved in end-to-end data transfer as a graph. We then formulate the problem whose goal is to achieve maximum data transfer throughput using parallel data flows. Our contributions lie in how to optimize data transfers considering all the system components involved rather than in accurately modeling all the system components involved. Our proposed formulations and solutions are evaluated through experiments on the ESnet 100G testbed. The experimental results show that our approach is several times faster than Globus Online - 8x faster for datasets with many 10MB files and 3-4x faster for other datasets of larger size files.","Title: Distributed multipath routing algorithm for data center networks\nYear: 2014\n\nAbstract: Multipath routing has been studied in diverse contexts such as wide-area networks and wireless networks in order to minimize the finish time of data transfer or the latency of message sending. The fast adoption of cloud computing for various applications including high-performance computing applications has drawn more attention to efficient network utilization through adaptive or multipath routing methods. However, the previous studies have not exploited multiple paths in an optimized way while scaling well with a large number of hosts for some reasons such as high time complexity of algorithms. In this paper, we propose a scalable distributed flow scheduling algorithm that can exploit multiple paths in data center networks. We develop our algorithm based on linear programming and evaluate the algorithm in FatTree network topologies, one of several advanced data center network topologies. The results show that the distributed algorithm performs much better than the centralized algorithm in terms of running time and is comparable to the centralized algorithm within 10% increased finish time in terms of data transfer time.","Title: Cluster-to-cluster data transfer with data compression over wide-area networks\nYear: 2015\n\nAbstract: The recent emergence of ultra high-speed networks up to 100 Gb/s has posed numerous challenges and has led to many investigations on efficient protocols to saturate 100 Gb/s links. However, end-to-end data transfers involve many components, not only protocols, affecting overall transfer performance. These components include disk I/O subsystem, additional computation associated with data streams, and network adapters. For example, achievable bandwidth by TCP may not be implementable if disk I/O or CPU becomes a bottleneck in end-to-end data transfer. In this paper, we first model all the system components involved in end-to-end data transfer as a graph. We then formulate the problem whose goal is to achieve maximum data transfer throughput using parallel data flows. We also propose a variable data flow GridFTP XIO stack to improve data transfer with data compression. Our contributions lie in how to optimize data transfers considering all the system components involved rather than in accurately modeling all the system components involved. Our proposed formulations and solutions are evaluated through experiments on the ESnet 100G testbed and a wide-area cluster-to-cluster testbed. The experimental results on the ESnet 100G testbed show that our approach is several times faster than Globus Online-8 í¿ faster for datasets with many 10¿MB files and 3-4 í¿ faster for other datasets of larger size files. The experimental results on the cluster-to-cluster testbed show that our variable data flow approach is up to 4 í¿ faster than a normal cluster data transfer. We model all the system components involved in end-to-end data transfer as a graph.We formulate the problem to optimize data transfer throughput using parallel flows.We propose a novel software I/O stack with variable parallel data flows per layer.Optimized parallel data flows improve overall data transfer throughput.The novel I/O stack with data compression alleviates network bottleneck situations.","Title: Improving sparse data movement performance using multiple paths on the Blue Gene/Q supercomputer.\nYear: 2016\n\nAbstract: •We adapt Ford–Fulkerson’s algorithm to find multiple disjoint paths to move data.•We realize multi-path data movement by introducing intermediate nodes to the paths.•We leverage routing policies to reduce the number of intermediate nodes.•We implement pipelined data movement with the Parallel Active Message Interface.","Title: Workflow performance improvement using model-based scheduling over multiple clusters and clouds\nYear: 2016\n\nAbstract: In recent years, a variety of computational sites and resources have emerged, and users often have access to multiple resources that are distributed. These sites are heterogeneous in nature and performance of different tasks in a workflow varies from one site to another. Additionally, users typically have a limited resource allocation at each site capped by administrative policies. In such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources so that the workload is balanced among sites and the overhead is minimized in data transfer. Most existing systems either run the entire workflow in a single site or use naïve approaches to distribute the tasks across sites or leave it to the user to optimize the allocation of tasks to distributed resources. This results in a significant loss in productivity. We propose a multi-site workflow scheduling technique that uses performance models to predict the execution time on resources and dynamic probes to identify the achievable network throughput between sites. We evaluate our approach using real world applications using the Swift parallel and distributed execution framework. We use two distinct computational environments-geographically distributed multiple clusters and multiple clouds. We show that our approach improves the resource utilization and reduces execution time when compared to the default schedule.","Title: Multipath Load Balancing for M × N Communication Patterns on the Blue Gene/Q Supercomputer Interconnection Network\nYear: 2015\n\nAbstract: Achievable networking performance of applications in a supercomputer depends on the exact combination of the communication patterns of the applications and the routing algorithms used by the supercomputer. In order to achieve the highest networking performance for the applications the routing algorithms need to be designed optimally for those communication patterns. However, while communication patterns usually have a wide variation from application to application and even from phase to phase in an application, routing algorithms have a limited variation and usually are optimized for typical communication patterns. This results in high networking performance for favored communication patterns but low networking performance for others. In this paper we present approaches for improving networking performance by rebalancing load on physical links on the Blue Gene Q supercomputer. We realize our approaches in a framework called OPTIQ and demonstrate the efficacy of our framework via a set of benchmarks. Our results show that we can achieve 30% higher throughput on experiment with data and patterns from a real application. The improvement can be up to several times higher throughput than default MPI_Alltoallv used in the Blue Gene Q supercomputer for certain communication patterns.","Title: Large-scale co-visualization for LAMMPS using vl3\nYear: 2015\n\nAbstract: In this poster we propose to interconnect LAMMPS and vl3, our parallel framework for large-scale visualization and analysis. The goal is co-visualization and exploration at interactive frame rates of large-scale atomistic simulations. We describe the architecture of the proposed system, as well as a preliminary implementation that runs on GPU-based visualization clusters.","Title: Streaming ultra high resolution images to large tiled display at nearly interactive frame rate with vl3\nYear: 2015\n\nAbstract: Visualization of large-scale simulations running on supercomputers requires ultra-high resolution images to capture important features in the data. In this work, we present a system for streaming ultra-high resolution images from a visualization cluster to a remote tiled display at nearly interactive frame rates. vl3, a modular framework for large scale data visualization and analysis, provides the backbone of our implementation. With this system we are able to stream over the network volume renderings of a 20483 voxel dataset at a resolution of 6144×3072 pixels with a frame rate of approximately 3.3 frames per second.","Title: Optimal scheduling of in-situ analysis for large-scale scientific simulations\nYear: 2015\n\nAbstract: Today's leadership computing facilities have enabled the execution of transformative simulations at unprecedented scales. However, analyzing the huge amount of output from these simulations remains a challenge. Most analyses of this output is performed in post-processing mode at the end of the simulation. The time to read the output for the analysis can be significantly high due to poor I/O bandwidth, which increases the end-to-end simulation-analysis time. Simulation-time analysis can reduce this end-to-end time. In this work, we present the scheduling of in-situ analysis as a numerical optimization problem to maximize the number of online analyses subject to resource constraints such as I/O bandwidth, network bandwidth, rate of computation and available memory. We demonstrate the effectiveness of our approach through two application case studies on the IBM Blue Gene/Q system.","Title: On-demand unstructured mesh translation for reducing memory pressure during in situ analysis\nYear: 2013\n\nAbstract: When coupling two different mesh-based codes, for example with in situ analytics, the typical strategy is to explicitly copy data (deep copy) from one implementation to another, doing translation in the process. This is necessary because codes usually do not share data model interfaces or implementations. The drawback is that data duplication results in an increased memory footprint for the coupled code. An alternative strategy, which we study in this paper, is to share mesh data through on-demand, fine-grained, run-time data model translation. This saves memory, which is an increasingly scarce resource at exascale, for the increased use of in situ analysis and decreasing memory per core. We study the performance of our method compared against a deep copy with in situ analysis at scale.","Title: Route-aware independent MPI I/O on the blue gene/Q.\nYear: 2015\n\nAbstract: Scalable high-performance I/O is crucial for application performance on large-scale systems. With the growing complexity of the system interconnects, it has become important to consider the impact of network contention on I/O performance because the I/O messages traverse several hops in the interconnect before reaching the I/O nodes or the file system. In this work, we present a route-aware and load-aware algorithm to modify existing bridge node assignment in the Blue Gene/Q (BG/Q) supercomputer. We reduce the network contention and reduce the write time by an average of 60% over the default independent I/O and by 20% over collective I/O on up to 8192 nodes on the Mira BG/Q system. Our algorithm routes 1.4x fewer messages through the bridge nodes which connect to the I/O nodes on the BG/Q.","Title: Modeling Cooperative Threads To Project Gpu Performance For Adaptive Parallelism\nYear: 2015\n\nAbstract: Most accelerators, such as graphics processing units (GPUs) and vector processors, are particularly suitable for accelerating massively parallel workloads. On the other hand, conventional workloads are developed for multi-core parallelism, which often scale to only a few dozen OpenMP threads. When hardware threads significantly outnumber the degree of parallelism in the outer loop, programmers are challenged with efficient hardware utilization. A common solution is to further exploit the parallelism hidden deep in the code structure. Such parallelism is less structured: parallel and sequential loops may be imperfectly nested within each other; neighboring inner loops may exhibit different concurrency patterns (e.g. reduction vs. forall), yet have to be parallelized in the same parallel section. Many input-dependent transformations have to be explored. A programmer often employs a larger group of hardware threads to cooperatively walk through a smaller outer loop partition and adaptively exploit any encountered parallelism. This process is time-consuming and error-prone, yet the risk of gaining little or no performance remains high for such workloads.To reduce risk and guide implementation, we propose a technique to model workloads with limited parallelism that can automatically explore and evaluate transformations involving cooperative threads. Eventually, our framework projects the best achievable performance and the most promising transformations without implementing GPU code or using physical hardware. We envision our technique to be integrated into future compilers or optimization frameworks for autotuning.","Title: Large-Scale Parallel Visualization of Particle-Based Simulations using Point Sprites and Level-Of-Detail.\nYear: 2015\n\nAbstract: Recent large-scale particle-based simulations are generating vast amounts of data posing a challenge to visualization algorithms. One possibility for addressing this challenge is to map particles into a regular grid for volume rendering, which carries the disadvantages of inefficient use of memory and undesired losses of dynamic range. As an alternative, we propose a method to efficiently visualize these massive particle datasets using point rendering techniques with neither loss of dynamic range nor memory overheads. In addition, a hierarchical reorganization of the data is desired to deliver meaningful visual representations of a large number of particles in a limited number of pixels, preserving point locality and also helping achieve interactive frame rates. In this paper, we present a framework for parallel rendering of large-scale particle data sets combining point sprites and z-ordering. The latter is used to create a multi level representation of the data which helps improving frame rates. Performance and scalability are evaluated on a GPU-based visualization cluster, scaling up to 128 GPUs. Results using particle datasets of up to 32 billion particles are shown.","Title: Improving Data Movement Performance for Sparse Data Patterns on the Blue Gene/Q Supercomputer\nYear: 2014\n\nAbstract: In-situ analysis has been proposed as a promising solution to glean faster insight and to reduce the amount of data written out to storage. A critical challenge here is that the reduced dataset needed to visualize a specific region of interest as the simulation is running is typically held on a subset of the nodes and needs to be written out to storage. Coupled multiphysics simulations also produce a sparse data pattern wherein data movement occurs among a subset of nodes. We evaluate the performance of these data patterns and propose several mechanisms for improving performance. Our mechanisms introduce intermediate nodes to implement multiple paths to transfer data on top of default routing algorithms and utilize topology-aware data aggregation to avoid shared bottleneck links. The efficacy of our solutions is evaluated through microbenchmarks and application benchmarks on an IBM Blue Gene/Q system scaling up to 131,072 compute cores. The results show that our algorithms achieve up to a 2X improvement in achievable throughput compared to the default mechanisms.","Title: Improving Communication Throughput by Multipath Load Balancing on Blue Gene/Q.\nYear: 2015\n\nAbstract: Achievable networking performance of applications in a supercomputer depends on the exact combination of the communication patterns of the applications and the routing algorithms used by the supercomputer. In order to achieve the highest networking performance for the applications, the routing algorithms need to be designed optimally for those communication patterns. However, while communication patterns usually vary from application to application and even from phase to phase in an application, routing algorithms have limited variation and usually are optimized for typical communication patterns. This results in high networking performance for some communication patterns. In this paper we present approaches for improving communication performance by using multiple paths and re-balancing load on physical links on the Blue Gene/Q supercomputer. We realize our approaches in a framework called OPTIQ and demonstrate the efficacy of our framework via a set of benchmarks. Our results show that we can achieve 43 -- 67% higher throughput on average from 91 experiments, and can achieve higher throughput than default MPI_Alltoallv used for certain communication patterns.","Title: TECA: Petascale Pattern Recognition for Climate Science\nYear: 2015\n\nAbstract: Climate Change is one of the most pressing challenges facing humanity in the 21st century. Climate simulations provide us with a unique opportunity to examine effects of anthropogenic emissions. High-resolution climate simulations produce \\\"Big Data\\\": contemporary climate archives are $$\\\\approx 5PB$$ in size and we expect future archives to measure on the order of Exa-Bytes. In this work, we present the successful application of TECA Toolkit for Extreme Climate Analysis framework, for extracting extreme weather patterns such as Tropical Cyclones, Atmospheric Rivers and Extra-Tropical Cyclones from TB-sized simulation datasets. TECA has been run at full-scale on Cray XE6 and IBM BG/Q systems, and has reduced the runtime for pattern detection tasks from years to hours. TECA has been utilized to evaluate the performance of various computational models in reproducing the statistics of extreme weather events, and for characterizing the change in frequency of storm systems in the future.","Title: In Situ Methods, Infrastructures, and Applications on High Performance Computing Platforms.\nYear: 2016\n\nAbstract: The considerable interest in the high performance computing (HPC) community regarding analyzing and visualization data without first writing to disk, i.e., in situ processing, is due to several factors. First is an I/O cost savings, where data is analyzed/visualized while being generated, without first storing to a filesystem. Second is the potential for increased accuracy, where fine temporal sampling of transient analysis might expose some complex behavior missed in coarse temporal sampling. Third is the ability to use all available resources, CPU's and accelerators, in the computation of analysis products. This STAR paper brings together researchers, developers and practitioners using in situ methods in extreme-scale HPC with the goal to present existing methods, infrastructures, and a range of computational science and engineering applications using in situ analysis and visualization.","Title: A data driven scheduling approach for power management on HPC systems.\nYear: 2016\n\nAbstract: Modern schedulers running on HPC systems traditionally consider the number of resources and the time requested for each job that is to be executed when making scheduling decisions. Until recently this has been sufficient, however as systems get larger, other metrics like power consumption become necessary to ensure system stability. In this paper, we propose a data driven scheduling approach for controlling the power consumption of the entire system under any user defined budget. Here, \\\"data driven\\\" means that our approach actively observes, analyzes, and assesses power behaviors of the system and user jobs to guide scheduling decisions for power management. This design is based on the key observation that HPC jobs have distinct power profiles. Our work contains an empirical analysis of workload power characteristics on a production system, dynamic learner to estimate the job power profile for scheduling, and an online power-aware scheduler for managing the overall system power. Using real workload traces, we demonstrate that our design effectively controls system power consumption while minimizing the impact on system utilization.","Title: Performance analysis, design considerations, and applications of extreme-scale in situ infrastructures.\nYear: 2016\n\nAbstract: A key trend facing extreme-scale computational science is the widening gap between computational and I/O rates, and the challenge that follows is how to best gain insight from simulation data when it is increasingly impractical to save it to persistent storage for subsequent visual exploration and analysis. One approach to this challenge is centered around the idea of in situ processing, where visualization and analysis processing is performed while data is still resident in memory. This paper examines several key design and performance issues related to the idea of in situ processing at extreme scale on modern platforms: scalability, overhead, performance measurement and analysis, comparison and contrast with a traditional post hoc approach, and interfacing with simulation codes. We illustrate these principles in practice with studies, conducted on large-scale HPC platforms, that include a miniapplication and multiple science application codes, one of which demonstrates in situ methods in use at greater than 1M-way concurrency.","Title: Optimal execution of co-analysis for large-scale molecular dynamics simulations.\nYear: 2016\n\nAbstract: The analysis of scientific simulation data enables scientists to derive insights from their simulations. This analysis of the simulation output can be performed at the same execution site as the simulation using the same resources or can be done at a different site. The optimal output frequency is challenging to decide and is often chosen empirically. We propose a mathematical formulation for choosing the optimal frequency of data transfer for analysis and the feasibility of performing the analysis, under the given resource constraints such as network bandwidth, disk space, available memory, and computation time. We propose formulations for two cases of co-analysis - local and remote. We consider various analyses features such as computation time, input data and memory requirement, importance of the analysis and minimum frequency required for performing the analysis. We demonstrate the effectiveness of our approach using molecular dynamics applications on the Mira and Edison supercomputers.","Title: Data movement optimizations for independent MPI I/O on the Blue Gene/Q.\nYear: 2017\n\nAbstract: •We propose algorithm to route data to closer IO nodes and reduce network congestion.•Developed a route-aware strategy to modify existing bridge node assignments in BG/Q.•Our algorithm reduces write times by 60% on average than default independent I/O.•The default independent MPI I/O routes 1.4x more I/O messages than our approach.•By intra-node aggregation, our modified independent I/O obtains 10.5 GB/s bandwidth.","Title: Topology-Aware Data Aggregation for Intensive I/O on Large-Scale Supercomputers.\nYear: 2016\n\nAbstract: Reading and writing data efficiently from storage systems is critical for high performance data-centric applications. These I/O systems are being increasingly characterized by complex topologies and deeper memory hierarchies. Effective parallel I/O solutions are needed to scale applications on current and future supercomputers. Data aggregation is an efficient approach consisting of electing some processes in charge of aggregating data from a set of neighbors and writing the aggregated data into storage. Thus, the bandwidth use can be optimized while the contention is reduced. In this work, we take into account the network topology for mapping aggregators and we propose an optimized buffering system in order to reduce the aggregation cost. We validate our approach using micro-benchmarks and the I/O kernel of a large-scale cosmology simulation. We show improvements up to 15X faster for I/O operations compared to a standard implementation of MPI I/O.","Title: Early Investigations into Using a Remote RAM Pool with the vl3 Visualization Framework.\nYear: 2016\n\nAbstract: This paper discusses early efforts to integrate the RAN remote memory technology into the vl3 volume rendering framework. We successfully demonstrate this integration, achieving 73% of the theoretical hardware maximum with minimal variation.","Title: Parallel distributed, GPU-accelerated, advanced lighting calculations for large-scale volume visualization\nYear: 2016\n\nAbstract: The benefits of applying advanced illumination models to volume visualization have been demonstrated by many researchers. For a parallel distributed, GPU computing environment, however, there is no efficient algorithm for scalable global illumination calculations. This paper presents a parallel, data-distributed and GPU-accelerated algorithm for volume rendering with advanced lighting. Our approach features tunable soft shadows for enhancing perception of complex spatial structures and relationships. For lighting calculations, our design effectively avoids data exchange among GPUs. Performance evaluation on a GPU cluster using up to 128 GPUs shows scalable rendering performance, with both the number of GPUs and volume data size.","Title: Analytical Performance Modeling and Validation of Intel's Xeon Phi Architecture.\nYear: 2017\n\nAbstract: Modeling the performance of scientific applications on emerging hardware plays a central role in achieving extreme-scale computing goals. Analytical models that capture the interaction between applications and hardware characteristics are attractive because even a reasonably accurate model can be useful for performance tuning before the hardware is made available. In this paper, we develop a hardware model for Intel's second-generation Xeon Phi architecture code-named Knights Landing (KNL) for the SKOPE framework. We validate the KNL hardware model by projecting the performance of minibenchmarks and application kernels. The results show that our KNL model can project the performance with prediction errors of 10% to 20%. The hardware model also provides informative recommendations for code transformations and tuning.","Title: A distributed graph approach for pre-processing linked RDF data using supercomputers\nYear: 2017\n\nAbstract: Efficient RDF, graph based queries are becoming more pertinent based on the increased interest in data analytics and its intersection with large, unstructured but connected data. Many commercial systems have adopted distributed RDF graph systems in order to handle increasing dataset sizes and complex queries. This paper introduces a distribute graph approach to pre-processing linked data. Instead of traversing the memory graph, our system indexes pre-processed join elements that are organized in a graph structure. We analyze the Dbpedia data-set (derived from the Wikipedia corpus) and compare our access method to the graph traversal access approach which we also devise. Results show from our experiments that the distributed, pre-processed graph approach to accessing linked data is faster than the traversal approach over a specific range of linked queries.","Title: PoLiMEr: An Energy Monitoring and Power Limiting Interface for HPC Applications\nYear: 2017\n\nAbstract: Power and energy consumption are now key design concerns in HPC. To develop software that meets power and energy constraints, scientific application developers must have a reliable way to measure these values and relate them to application-specific events. Scientists face two challenges when measuring and controlling power: (1) diversity---power and energy measurement interfaces differ between vendors---and (2) distribution---power measurements of MPI simulations should be unaffected by the mapping of MPI processes to physical hardware nodes. While some prior work defines standardized software interfaces for power management, these efforts do not support distributed environments. The result is that the current state-of-the-art requires scientists interested in power optimization to write tedious, error-prone application-and system-specific code. To make power measurement and management easier for scientists, we propose PoLiMEr, a user-space library that supports fine-grained application-level power monitoring and capping. We evaluate PoLiMEr by deploying it on Argonne National Laboratory's Theta system and using it to measure and cap power, scaling the performance and power of several applications on up to 1024 nodes. We find that PoLiMEr requires only a few additional lines of code, but easily allows users to detect energy anomalies, apply power caps, and evaluate Theta's unique architectural features.","Title: TAPIOCA: An I/O Library for Optimized Topology-Aware Data Aggregation on Large-Scale Supercomputers\nYear: 2017\n\nAbstract: Reading and writing data efficiently from storage system is necessary for most scientific simulations to achieve good performance at scale. Many software solutions have been developed to decrease the I/O bottleneck. One well-known strategy, in the context of collective I/O operations, is the two-phase I/O scheme. This strategy consists of selecting a subset of processes to aggregate contiguous pieces of data before performing reads/writes. In this paper, we present TAPIOCA, an MPI-based library implementing an efficient topology-aware two-phase I/O algorithm. We show how TAPIOCA can take advantage of double-buffering and one-sided communication to reduce as much as possible the idle time during data aggregation. We also introduce our cost model leading to a topology-aware aggregator placement optimizing the movements of data. We validate our approach at large scale on two leadership-class supercomputers: Mira (IBM BG/Q) and Theta (Cray XC40). We present the results obtained with TAPIOCA on a micro-benchmark and the I/O kernel of a large-scale simulation. On both architectures, we show a substantial improvement of I/O performance compared with the default MPI I/O implementation. On BG/Q+GPFS, for instance, our algorithm leads to a performance improvement by a factor of twelve while on the Cray XC40 system associated with a Lustre filesystem, we achieve an improvement of four.","Title: Scalable In situ Analysis of Molecular Dynamics Simulations.\nYear: 2017\n\nAbstract: Analysis of scientific simulation data enables scientists to glean insight from simulations. In situ analysis, which can be simultaneously executed with the simulation, mitigates I/O bottlenecks and can accelerate discovery of new phenomena. However, in typical modes of operation, this requires either stalling simulation during analysis phase or transferring data for analysis. We study the scalability challenges of time- and space-shared modes of analyzing large-scale molecular dynamics simulations. We also propose topology-aware mapping for simulation and analysis. We demonstrate the benefits of our approach using LAMMPS code on two supercomputers.","Title: Toward Scalable and Asynchronous Object-Centric Data Management for HPC\nYear: 2018\n\nAbstract: Emerging high performance computing (HPC) systems are expected to be deployed with an unprecedented level of complexity due to a deep system memory and storage hierarchy. Efficient and scalable methods of data management and movement through this hierarchy is critical for scientific applications using exascale systems. Moving toward new paradigms for scalable I/O in the extreme-scale era, we introduce novel object-centric data abstractions and storage mechanisms that take advantage of the deep storage hierarchy, named Proactive Data Containers (PDC). In this paper, we formulate object-centric PDCs and their mappings in different levels of the storage hierarchy. PDC adopts a client-server architecture with a set of servers managing data movement across storage layers. To demonstrate the effectiveness of the proposed PDC system, we have measured performance of benchmarks and I/O kernels from scientific simulation and analysis applications using PDC programming interface, and compared the results with existing highly tuned I/O libraries. Using asynchronous I/O along with data and metadata optimizations, PDC demonstrates up to 23× speedup over HDF5 and PLFS in writing and reading data from a plasma physics simulation. PDC achieves comparable performance with HDF5 and PLFS in reading and writing data of a single timestep at small scale, and outperforms them at a scale of larger than 10K cores. In contrast to existing storage systems, PDC offers user-space data management with the flexibility to allocate the number of PDC servers depending on the workload.","Title: Optimizing Data Aggregation by Leveraging the Deep Memory Hierarchy on Large-scale Systems.\nYear: 2018\n\nAbstract: Effective data aggregation is of paramount importance for data-centric applications in order to improve data movement for I/O or to facilitate complex workflows, such as in-situ analysis, as well as coupling models and data for multi-physics. A key challenge for data aggregation in current and upcoming architectures is the heterogeneity of memory and storage systems (including DRAM, MCDRAM, NVRAM or parallel file system). One has to take advantage of this hierarchy and the characteristics of each tier to achieve improved performance at scale. In this paper, we present a topology and memory-aware data movement library performing data aggregation on large-scale systems. We first detail our hardware abstraction layer to accomplish code and performance portability on various platforms. Next, we present a cost model taking into account the system interconnect and the memory properties to determine an appropriate location for aggregating data. We also describe how we have implemented a data aggregation mechanism through the read algorithm. Finally, we show how we can improve data movement on a visualization cluster and a leadership-class supercomputer up to 16K processes with a benchmark and two typical I/O kernels. Particularly, we demonstrate how our approach can decrease the I/O time of a classic workflow by 26%.","Title: Topology-aware space-shared co-analysis of large-scale molecular dynamics simulations.\nYear: 2018\n\nAbstract: Analysis of scientific simulation data can be concurrently executed with simulation either in time- or space-shared mode. This mitigates the I/O bottleneck, however it results in either stalling the simulation for performing the analysis or transferring data for analysis. In this paper, we improve the throughput of space-shared in situ analysis of large-scale simulations by topology-aware mapping and optimal process decomposition. We propose node interconnect topology-aware process placement for simulation and analysis to reduce the data movement time. We also present an integer linear program for optimal 3D decompositions of simulation and analysis processes. We demonstrate our approach using molecular dynamics simulation on Mira, Cori and Theta supercomputers. Our mapping schemes, combined with optimal 3D process decomposition and code optimizations resulted in up to 30% lower execution times for space-shared in situ analysis than the default approach. Our mappings also reduce MPI collective I/O times by 10–40%.","Title: libIS - a lightweight library for flexible in transit visualization.\nYear: 2018\n\nAbstract: As simulations grow in scale, the need for in situ analysis methods to handle the large data produced grows correspondingly. One desirable approach to in situ visualization is in transit visualization. By decoupling the simulation and visualization code, in transit approaches alleviate common difficulties with regard to the scalability of the analysis, ease of integration, usability, and impact on the simulation. We present libIS, a lightweight, flexible library which lowers the bar for using in transit visualization. Our library works on the concept of abstract regions of space containing data, which are transferred from the simulation to the visualization clients upon request, using a client-server model. We also provide a SENSEI analysis adaptor, which allows for transparent deployment of in transit visualization. We demonstrate the flexibility of our approach on batch analysis and interactive visualization use cases on different HPC resources.","Title: A Visual Analytics System for Optimizing Communications in Massively Parallel Applications\nYear: 2017\n\nAbstract: Current and future supercomputers have tens of thousands of compute nodes interconnected with high-dimensional networks and complex network topologies for improved performance. Application developers are required to write scalable parallel programs in order to achieve high throughput on these machines. Application performance is largely determined by efficient inter-process communication. A common way to analyze and optimize performance is through profiling parallel codes to identify communication bottlenecks. However, understanding gigabytes of profiled at a is not a trivial task. In this paper, we present a visual analytics system for identifying the scalability bottlenecks and improving the communication efficiency of massively parallel applications. Visualization methods used in this system are designed to comprehend large-scale and varied communication patterns on thousands of nodes in complex networks such as the 5D torus and the dragonfly. We also present efficient rerouting and remapping algorithms that can be coupled with our interactive visual analytics design for performance optimization. We demonstrate the utility of our system with several case studies using three benchmark applications on two leading supercomputers. The mapping suggestion from our system led to 38% improvement in hop-bytes for Mini AMR application on 4,096 MPI processes.","Title: Benchmarking Machine Learning Methods for Performance Modeling of Scientific Applications\nYear: 2018\n\nAbstract: Performance modeling is an important and active area of research in high-performance computing (HPC). It helps in better job scheduling and also improves overall performance of coupled applications. Sufficiently rich analytical models are challenging to develop, however, because of interactions between different node components, network topologies, job interference, and application complexity. When analytical performance models become restrictive because of application dynamics and/or multicomponent interactions, machine-learning-based performance models can be helpful. While machine learning (ML) methods do not require underlying system or application knowledge, they are efficient in learning the unknown interactions of the application and system parameters empirically using application runs. We present a benchmark study in which we evaluate eleven machine learning methods for modeling the performance of four representative scientific applications that are irregular and with skewed domain configurations on four leadership-class HPC platforms. We assess the impact of feature engineering, size of training set, modern hardware platforms, transfer learning, extrapolation on the prediction accuracy, and training and inference times. We find that bagging, boosting, and deep neural network ML methods are promising approaches with median \n<tex xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">$R^{2}$</tex>\n values greater than 0.95 and these methods do not require feature engineering. We demonstrate that cross-platform performance prediction can be improved significantly using transfer learning with deep neural networks.","Title: A Benchmarking Study to Evaluate Apache Spark on Large-Scale Supercomputers.\nYear: 2019\n\nAbstract: As dataset sizes increase, data analysis tasks in high performance computing (HPC) are increasingly dependent on sophisticated dataflows and out-of-core methods for efficient system utilization. In addition, as HPC systems grow, memory access and data sharing are becoming performance bottlenecks. Cloud computing employs a data processing paradigm typically built on a loosely connected group of low-cost computing nodes without relying upon shared storage and/or memory. Apache Spark is a popular engine for large-scale data analysis in the cloud, which we have successfully deployed via job submission scripts on production clusters. In this paper, we describe common parallel analysis dataflows for both Message Passing Interface (MPI) and cloud based applications. We developed an effective benchmark to measure the performance characteristics of these tasks using both types of systems, specifically comparing MPI/C-based analyses with Spark. The benchmark is a data processing pipeline representative of a typical analytics framework implemented using map-reduce. In the case of Spark, we also consider whether language plays a role by writing tests using both Python and Scala, a language built on the Java Virtual Machine (JVM). We include performance results from two large systems at Argonne National Laboratory including Theta, a Cray XC40 supercomputer on which our experiments run with 65,536 cores (1024 nodes with 64 cores each). The results of our experiments are discussed in the context of their applicability to future HPC architectures. Beyond understanding performance, our work demonstrates that technologies such as Spark, while typically aimed at multi-tenant cloud-based environments, show promise for data analysis needs in a traditional clustering/supercomputing environment.","Title: Scaling Distributed Training of Flood-Filling Networks on HPC Infrastructure for Brain Mapping.\nYear: 2019\n\nAbstract: Mapping all the neurons in the brain requires automatic reconstruction of entire cells from volume electron microscopy data. The flood-filling networks (FFN) architecture can achieve leading performance. However, the training of the network is computationally very expensive. In order to reduce the training time, we implemented synchronous and data-parallel distributed training using the Horovod framework on top of the published FFN code. We demonstrated the scaling of FFN training up to 1024 Intel Knights Landing (KNL) nodes at Argonne Leadership Computing Facility. We investigated the training accuracy with different optimizers, learning rates, and optional warm-up periods. We discovered that square root scaling for learning rate works best beyond 16 nodes, which is contrary to the case of smaller number of nodes, where linear learning rate scaling with warm-up performs the best. Our distributed training reaches 95% accuracy in approximately 4.5 hours on 1024 KNL nodes using Adam optimizer.","Title: A Machine Learning Workflow For Molecular Analysis: Application To Melting Points\nYear: 2020\n\nAbstract: Computational tools encompassing integrated molecular prediction, analysis, and generation are key for molecular design in a variety of critical applications. In this work, we develop a workflow for molecular analysis (MOLAN) that integrates an ensemble of supervised and unsupervised machine learning techniques to analyze molecular data sets. The MOLAN workflow combines molecular featurization, clustering algorithms, uncertainty analysis, low-bias dataset construction, high-performance regression models, graph-based molecular embeddings and attribution, and a semi-supervised variational autoencoder based on the novel SELFIES representation to enable molecular design. We demonstrate the utility of the MOLAN workflow in the context of a challenging multi-molecule property prediction problem: the determination of melting points solely from single molecule structure. This application serves as a case study for how to employ the MOLAN workflow in the context of molecular property prediction.","Title: DLIO: A Data-Centric Benchmark for Scientific Deep Learning Applications\nYear: 2021\n\nAbstract: Deep learning has been shown as a successful method for various tasks, and its popularity results in numerous open-source deep learning software tools. Deep learning has been applied to a broad spectrum of scientific domains such as cosmology, particle physics, computer vision, fusion, and astrophysics. Scientists have performed a great deal of work to optimize the computational performance of deep learning frameworks. However, the same cannot be said for I/O performance. As deep learning algorithms rely on big-data volume and variety to effectively train neural networks accurately, I/O is a significant bottleneck on large-scale distributed deep learning training. This study aims to provide a detailed investigation of the I/O behavior of various scientific deep learning workloads running on the Theta supercomputer at Argonne Leadership Computing Facility. In this paper, we present DLIO, a novel representative benchmark suite built based on the I/O profiling of the selected workloads. DLIO can be utilized to accurately emulate the I/O behavior of modern scientific deep learning applications. Using DLIO, application developers and system software solution architects can identify potential I/O bottlenecks in their applications and guide optimizations to boost the I/O performance leading to lower training times by up to 6.7x.","Title: Stream-AI-MD: Streaming AI-driven Adaptive Molecular Simulations for Heterogeneous Computing Platforms\nYear: 2021\n\nAbstract: Emerging hardware tailored for artificial intelligence (AI) and machine learning (ML) methods provide novel means to couple them with traditional high performance computing (HPC) workflows involving molecular dynamics (MD) simulations. We propose StreamAI-MD, a novel instance of applying deep learning methods to drive adaptive MD simulation campaigns in a streaming manner. We leverage the ability to run ensemble MD simulations on GPU clusters, while the data from atomistic MD simulations are streamed continuously to AI/ML approaches to guide the conformational search in a biophysically meaningful manner on a wafer-scale AI accelerator. We demonstrate the efficacy of Stream-AI-MD simulations for two scientific use-cases: (1) folding a small prototypical protein, namely beta beta alpha-fold (BBA) FSD-EY and (2) understanding protein-protein interaction (PPI) within the SARS-CoV-2 proteome between two proteins, nsp16 and nsp10. We show that Stream-AI-MD simulations can improve time-to-solution by similar to 50X for BBA protein folding. Further, we also discuss performance trade-offs involved in implementing AI-coupled HPC workflows on heterogeneous computing architectures.","Title: MLPerf™ HPC: A Holistic Benchmark Suite for Scientific Machine Learning on HPC Systems\nYear: 2021\n\nAbstract: Scientific communities are increasingly adopting machine learning and deep learning models in their applications to accelerate scientific insights. High performance computing systems are pushing the frontiers of performance with a rich diversity of hardware resources and massive scale-out capabilities. There is a critical need to understand fair and effective benchmarking of machine learning appli...","Title: AgEBO-tabular: joint neural architecture and hyperparameter search with autotuned data-parallel training for tabular data\nYear: 2021\n\nAbstract: ABSTRACTDeveloping high-performing predictive models for large tabular data sets is a challenging task. Neural architecture search (NAS) is an AutoML approach that generates and evaluates multiple neural networks with different architectures concurrently to automatically discover an high performing model. A key issue in NAS, particularly for large data sets, is the large computation time required to evaluate each generated architecture. While data-parallel training has the potential to address this issue, a straightforward approach can result in significant loss of accuracy. To that end, we develop AgEBO-Tabular, which combines Aging Evolution (AE) to search over neural architectures and asynchronous Bayesian optimization (BO) to search over hyperparameters to adapt data-parallel training. We evaluate the efficacy of our approach on two large predictive modeling tabular data sets from the Exascale Computing Project-CANcer Distributed Learning Environment (ECP-CANDLE).","Title: Efficient Design Space Exploration for Sparse Mixed Precision Neural Architectures\nYear: 2022\n\nAbstract: BSTRACTPruning and Quantization are two effective Deep Neural Network (DNN) compression methods for efficient inference on various hardware platforms. Pruning refers to removing unimportant weights or nodes, whereas Quantization converts the floating-point parameters to low-bit fixed integer representation. The pruned and low precision models result in smaller and faster inference models on hardware platforms with almost the same accuracy as the unoptimized network. Tensor Cores in Nvidia Ampere 100 (A100) GPU supports (1) 2:4 fine-grained sparse pruning where 2 out of every 4 elements are pruned, and (2) traditional dense multiplication to achieve a good accuracy and performance trade-off. The A100 Tensor Core also takes advantage of 1-bit, 4-bit, and 8-bit multiplication to speed up the inference of a model. Hence, finding the right matrix type (dense or 2:4 sparse) along with the precision for each layer becomes a combinatorial problem. Neural Architecture Search (NAS) can alleviate such problems by automating the architecture design process instead of a brute-force search. In this paper, we propose (i) Mixed Sparse and Precision Search (MSPS), a NAS framework to search for efficient sparse and mixed-precision quantized model within the predefined search space and fixed backbone neural network (Eg. ResNet50), and (ii) Architecture, Sparse and Precision Search (ASPS) to jointly search for kernel size and number of filters, and sparse-precision combination of each layer. We illustrate the effectiveness of our methods targeting A100 Tensor Core on Nvidia GPUs by searching efficient sparse-mixed precision networks on ResNet50 and achieving better accuracy-latency trade-off models compared to the manually designed Uniform Sparse Int8 networks.","Title: Stimulus: Accelerate Data Management for Scientific AI applications in HPC\nYear: 2022\n\nAbstract: Modern scientific workflows couple simulations with AI-powered analytics by frequently exchanging data to accelerate time-to-science to reduce the complexity of the simulation planes. However, this data exchange is limited in performance and portability due to a lack of support for scientific data formats in AI frameworks. We need a cohesive mechanism to effectively integrate at scale complex scientific data formats such as HDF5, PnetCDF, ADIOS2, GNCF, and Silo into popular AI frameworks such as TensorFlow, PyTorch, and Caffe. To this end, we designed Stimulus, a data management library for ingesting scientific data effectively into the popular AI frameworks. We utilize the StimOps functions along with StimPack abstraction to enable the integration of scientific data formats with any AI framework. The evaluations show that Stimulus outperforms several large-scale applications with different use-cases such as Cosmic Tagger (consuming HDF5 dataset in PyTorch), Distributed FFN (consuming HDF5 dataset in TensorFlow), and CosmoFlow (converting HDF5 into TFRecord and then consuming that in TensorFlow) by 5.3 x, 2.9 x, and 1.9 x respectively with ideal I/O scalability up to 768 GPUs on the Summit supercomputer. Through Stimulus, we can portably extend existing popular AI frameworks to cohesively support any complex scientific data format and efficiently scale the applications on large-scale supercomputers.","Title: Toward an In-Depth Analysis of Multifidelity High Performance Computing Systems\nYear: 2022\n\nAbstract: To maintain a robust and reliable supercomputing facility, monitoring it and understanding its hardware system events and behaviors is an essential task. Exascale systems will be increasingly heterogeneous, and the volume of systems data, collected from multiple subsystems and components measured at multiple fidelity levels and temporal resolutions, will continue to grow. In this work, we aim to create an effective solution to analyze diverse and massive datasets gathered from the error logs, job logs, and environment logs of an HPC system, such as a Cray XC40 supercomputer. In this work, we build an end-to-end error log analysis system that analyzes the job logs and gleans insights from their correspondence with hardware error logs and environment logs despite their varying temporal and spatial resolutions. Our machine learning pipeline built in our system is ~92% accurate in predicting the job exit status and does so with sufficient lead time for evasive actions to be taken before the actual failure event occurs.","Title: HDF5 Cache VOL: Efficient and Scalable Parallel I/O through Caching Data on Node-local Storage\nYear: 2022\n\nAbstract: Modern-era high performance computing (HPC) systems are providing multiple levels of memory and storage layers to bridge the performance gap between fast memory and slow disk-based storage system managed by Lustre or GPFS. Several of the recent HPC systems are equipped with SSD and NVMe-based storage that is attached locally to compute nodes. A few systems are providing an SSD-based “burst buffer” intermediate storage layer that is accessible by all compute nodes as a single file system. Although these hardware layers are intended to reduce the latency gap between memory and disk-based long-term storage, how to utilize them has been left to the users. High-level I/O libraries, such as HDF5 and netCDF, can potentially take advantage of the node-local storage as a cache for reducing I/O latency from capacity storage. However, it is challenging to use node-local storage in parallel I/O especially for a single shared file. In this paper, we present an approach to integrate node-local storage as transparent caching or staging layers in a high-level parallel I/O library without placing the burden of managing these layers on users. We designed this to move data asynchronously between the caching storage layer and a parallel file system to overlap the data movement overhead in performing I/O with compute phases. We implement this approach as an external HDF5 Virtual Object Layer (VOL) connector, named Cache VOL. HDF5 VOL is a layer of abstraction in HDF5 that allows intercepting the public HDF5 application programming interface (API) and performing various optimizations to data movement after the interception. Existing HDF5 applications can use Cache VOL with minimal code modifications. We evaluated the performance of Cache VOL in HPC applications such as VPIC-10, and deep learning applications such as ImageNet and CosmoFlow. We show that using Cache VOL, one can achieve higher observed I/O performance, more scalable and stable I/O compared to direct I/O to the parallel file system, thus achieving faster time-to-solution in scientific simulations. While the caching approach is implemented in HDF5, the methods are applicable in other high-level I/O libraries.","Title: Neural Architecture Search for Transformers: A Survey\nYear: 2022\n\nAbstract: Transformer-based Deep Neural Network architectures have gained tremendous interest due to their effectiveness in various applications across Natural Language Processing (NLP) and Computer Vision (CV) domains. These models are the de facto choice in several language tasks, such as Sentiment Analysis and Text Summarization, replacing Long Short Term Memory (LSTM) model. Vision Transformers (ViTs) have shown better model performance than traditional Convolutional Neural Networks (CNNs) in vision applications while requiring significantly fewer parameters and training time. The design pipeline of a neural architecture for a given task and dataset is extremely challenging as it requires expertise in several interdisciplinary areas such as signal processing, image processing, optimization and allied fields. Neural Architecture Search (NAS) is a promising technique to automate the architectural design process of a Neural Network in a data-driven way using Machine Learning (ML) methods. The search method explores several architectures without requiring significant human effort, and the searched models outperform the manually built networks. In this paper, we review Neural Architecture Search techniques, targeting the Transformer model and its family of architectures such as Bidirectional Encoder Representations from Transformers (BERT) and Vision Transformers. We provide an in-depth literature review of approximately 50 state-of-the-art Neural Architecture Search methods and explore future directions in this fast-evolving class of problems."],"string":"[\n \"Title: ALCF MPI Benchmarks: Understanding Machine-Specific Communication Behavior\\nYear: 2012\\n\\nAbstract: As systems grow larger and computation is further spread across nodes, efficient data communication is becoming increasingly important to achieve high throughput and low power consumption for high performance computing systems. However, communication efficacy not only depends on application-specific communication patterns, but also on machine-specific communication subsystems, node architectures, and even the runtime communication libraries. In fact, different hardware systems lead to different tradeoffs with respect to communication mechanisms, which can impact the choice of application implementations. We present a set of MPI-based benchmarks to better understand the communication behavior of the hardware systems and guide the performance tuning of scientific applications. We further apply these benchmarks to three clusters and present several interesting lessons from our experience.\",\n \"Title: Specification and Verification of LambdaRAM: A Wide-area Distributed Cache for High Performance Computing\\nYear: 2008\\n\\nAbstract: LambdaRAM is a high-performance, multidimensional, wide-area, distributed cache that takes advantage of massively available memory from multiple clusters interconnected by ultra high-speed networking to provide data-intensive scientific applications with rapid access to both local and remote data without suffering the latency bottlenecks often associated with large storage systems and wide-area data access. LambdaRAM has been demonstrated to yield significant performance speed-ups for Geophysical and Bioscience applications accessing extremely large datasets. Currently, LambdaRAM is being integrated by NASA for the Modelling, Analysis and Prediction (MAP) Program applications to study tropical cyclones. Formal verification of LambdaRAM is important to NASA to ensure that LambdaRAM operates reliably in real-time mission critical deployments. We present ourpreliminary steps towardsfullformal verification of LambdaRAM. We first give an abstract description of the system and then verify several of its properties. Most of the proofs are accomplished by automatic techniques, while some require deductive steps.\",\n \"Title: Accelerating I/O Forwarding in IBM Blue Gene/P Systems\\nYear: 2010\\n\\nAbstract: Current leadership-class machines suffer from a significant imbalance between their computational power and their I/O bandwidth. I/O forwarding is a paradigm that attempts to bridge the increasing performance and scalability gap between the compute and I/O components of leadership-class machines to meet the requirements of data-intensive applications by shipping I/O calls from compute nodes to dedicated I/O nodes. I/O forwarding is a critical component of the I/O subsystem of the IBM Blue Gene/P supercomputer currently deployed at several leadership computing facilities. In this paper, we evaluate the performance of the existing I/O forwarding mechanisms for BG/P and identify the performance bottlenecks in the current design. We augment the I/O forwarding with two approaches: I/O scheduling using a work-queue model and asynchronous data staging. We evaluate the efficacy of our approaches using microbenchmarks and application-level benchmarks on leadership class systems.\",\n \"Title: Job Coscheduling on Coupled High-End Computing Systems\\nYear: 2011\\n\\nAbstract: Supercomputer centers often deploy large-scale computing systems together with an associated data analysis or visualization system. In this paper, we propose a co scheduling mechanism, providing the ability to coordinate execution between jobs on different systems. The mechanism is built on top of a lightweight protocol for coordination between policy domains without manual intervention. We have evaluated this system using real job traces from Intrepid and Eureka, the production Blue Gene/P and data analysis systems, respectively, deployed at Argonne National Laboratory. Our experimental results quantify the costs of co scheduling and demonstrate that co scheduling can be achieved with limited impact on system performance under varying workloads.\",\n \"Title: The OptIPortal, a scalable visualization, storage, and computing interface device for the OptiPuter\\nYear: 2009\\n\\nAbstract: The OptIPortal is a tiled display that is the visual interface to the OptIPuter, a global-scale computing system tied together by tens of gigabits of networking. The main point of the OptIPuter project is to examine a ''future'' in which networking is not a bottleneck to local, regional, national and international computing. OptIPortals are designed to allow collaborative sharing over 1-10 gigabit/second networks of extremely high-resolution graphic output, as well as video streams. OptIPortals typically consist of an array of 4 to 70 LCD display panels (either 2-megapixel or 4-megapixel each), driven by an appropriately sized cluster of PCs, with optimized graphics processors and network interface cards. Rather than exist as one-of-a-kind laboratory prototypes, OptIPortals are designed to be openly and widely replicated, balancing the state of the art of PCs, graphic processing, networks, servers, software, middleware, and user interfaces, and installed in the context of a laboratory or office conference room. Discussed in detail are the design decisions made to achieve a replicable tiled display that can be built by computational science researchers in various disciplines.\",\n \"Title: Electronic poster: co-visualization of full data and in situ data extracts from unstructured grid cfd at 160k cores\\nYear: 2011\\n\\nAbstract: Scalability and time-to-solution studies have historically been focused on the size of the problem and run time. We consider a more strict definition of \\\"solution\\\" whereby a live data analysis (co-visualization of either the full data or in situ data extracts) provides continuous and reconfigurable insight into massively parallel simulations. Specifically, we used the Argonne Leadership Class Facility's (ALCF) BlueGene/P machine with 163,840 cores tightly linked through a high-speed network to 100 visualization nodes that share 800 cores and 200 GPUs. Three meshes with respectively 52M, 416M and 3.3B elements discretize the flow over a full swept wing with an unsteady synthetic jet to evaluate time-to-solution plus insight. On the full machine, the 416M element mesh takes about 2 seconds per flow solve step including the extraction and rendering of a slice or a contour, slowing currently the simulation by only 10 and 15% respectively. The 3.3B element case proved scalable at about 15 seconds per time step, whereas PHASTA's strong scaling could compress the time-to-solution for the 52M element case enough to allow the rendering of one frame (slice or contour) every 0.7 second, paving the way for interactive simulation and simulation steering on massively parallel systems1.\",\n \"Title: Fast Multiresolution Reads of Massive Simulation Datasets\\nYear: 2014\\n\\nAbstract: Today's massively parallel simulation codes can produce output ranging up to many terabytes of data. Utilizing this data to support scientific inquiry requires analysis and visualization, yet the sheer size of the data makes it cumbersome or impossible to read without computational resources similar to the original simulation. We identify two broad classes of problems for reading data and present effective solutions for both. The first class of data reads depends on user requirements and available resources. Tasks such as visualization and user-guided analysis may be accomplished using only a subset of variables with a restricted spatial extent at a reduced resolution. The other class of reads requires full resolution multivariate data to be loaded, for example to restart a simulation. We show that utilizing the hierarchical multiresolution IDX data format enables scalable and efficient serial and parallel read access on a variety of hardware from supercomputers down to portable devices. We demonstrate interactive view-dependent visualization and analysis of massive scientific datasets using low-power commodity hardware, and we compare read performance with other parallel file formats for both full and partial resolution data.\",\n \"Title: Scalable in situ scientific data encoding for analytical query processing\\nYear: 2013\\n\\nAbstract: The process of scientific data analysis in high-performance computing environments has been evolving along with the advancement of computing capabilities. With the onset of exascale computing, the increasing gap between compute performance and I/O bandwidth has rendered the traditional method of post-simulation processing a tedious process. Despite the challenges due to increased data production, there exists an opportunity to benefit from \\\"cheap\\\" computing power to perform query-driven exploration and visualization during simulation time. To accelerate such analyses, applications traditionally augment raw data with large indexes, post-simulation, which are then repeatedly utilized for data exploration. However, the generation of current state-of-the-art indexes involve a compute- and memory-intensive processing, thus rendering them inapplicable in an in situ context. In this paper we propose DIRAQ, a parallel in situ, in network data encoding and reorganization technique that enables the transformation of simulation output into a query-efficient form, with negligible runtime overhead to the simulation run. DIRAQ begins with an effective core-local, precision-based encoding approach, which incorporates an embedded compressed index that is 3 -- 6x smaller than current state-of-the-art indexing schemes. DIRAQ then applies an in network index merging strategy, enabling the creation of aggregated indexes ideally suited for spatial-context querying that speed up query responses by up to 10x versus alternative techniques. We also employ a novel aggregation strategy that is topology-, data-, and memory-aware, resulting in efficient I/O and yielding overall end-to-end encoding and I/O time that is less than that required to write the raw data with MPI collective I/O.\",\n \"Title: PIDX: Efficient Parallel I/O for Multi-resolution Multi-dimensional Scientific Datasets\\nYear: 2011\\n\\nAbstract: The IDX data format provides efficient, cache oblivious, and progressive access to large-scale scientific datasets by storing the data in a hierarchical Z (HZ) order. Data stored in IDX format can be visualized in an interactive environment allowing for meaningful explorations with minimal resources. This technology enables real-time, interactive visualization and analysis of large datasets on a variety of systems ranging from desktops and laptop computers to portable devices such as iPhones/iPads and over the web. While the existing ViSUS API for writing IDX data is serial, there are obvious advantages of applying the IDX format to the output of large scale scientific simulations. We have therefore developed PIDX - a parallel API for writing data in an IDX format. With PIDX it is now possible to generate IDX datasets directly from large scale scientific simulations with the added advantage of real-time monitoring and visualization of the generated data. In this paper, we provide an overview of the IDX file format and how it is generated using PIDX. We then present a data model description and a novel aggregation strategy to enhance the scalability of the PIDX library. The S3D combustion application is used as an example to demonstrate the efficacy of PIDX for a real-world scientific simulation. S3D is used for fundamental studies of turbulent combustion requiring exceptionally high fidelity simulations. PIDX achieves up to 18 GiB/s I/O throughput at 8,192 processes for S3D to write data out in the IDX format. This allows for interactive analysis and visualization of S3D data, thus, enabling in situ analysis of S3D simulation.\",\n \"Title: Dataflow-driven GPU performance projection for multi-kernel transformations\\nYear: 2012\\n\\nAbstract: Applications often have a sequence of parallel operations to be offloaded to graphics processors; each operation can become an individual GPU kernel. Developers typically explore a variety of transformations for each kernel. Furthermore, it is well known that efficient data management is critical in achieving high GPU performance and that \\\"fusing\\\" multiple kernels into one may greatly improve data locality. Doing so, however, requires transformations across multiple, potentially nested, parallel loops; at the same time, the original code semantics and data dependency must be preserved. Since each kernel may have distinct data access patterns, their combined dataflow can be nontrivial. As a result, the complexity of multi-kernel transformations often leads to significant effort with no guarantee of performance benefits. This paper proposes a dataflow-driven analytical framework to project GPU performance for a sequence of parallel operations. Users need only provide CPU code skeletons for a sequence of parallel loops. The framework can then automatically identify opportunities for multi-kernel transformations and data management. It is also able to project the overall performance without implementing GPU code or using physical hardware.\",\n \"Title: Topology-aware data movement and staging for I/O acceleration on Blue Gene/P supercomputing systems\\nYear: 2011\\n\\nAbstract: There is growing concern that I/O systems will be hard pressed to satisfy the requirements of future leadership-class machines. Even current machines are found to be I/O bound for some applications. In this paper, we identify existing performance bottlenecks in data movement for I/O on the IBM Blue Gene/P (BG/P) supercomputer currently deployed at several leadership computing facilities. We improve the I/O performance by exploiting the network topology of BG/P for collective I/O, leveraging data semantics of applications and incorporating asynchronous data staging. We demonstrate the efficacy of our approaches for synthetic benchmark experiments and for application-level benchmarks at scale on leadership computing systems.\",\n \"Title: Accelerating tropical cyclone analysis using LambdaRAM, a distributed data cache over wide-area ultra-fast networks\\nYear: 2009\\n\\nAbstract: Data-intensive scientific applications require rapid access to local and geographically distributed data, however, there are significant I/O latency bottlenecks associated with storage systems and wide-area networking. LambdaRAM is a high-performance, multi-dimensional, distributed cache, that takes advantage of memory from multiple clusters interconnected by ultra-high-speed networking, to provide applications with rapid access to both local and remote data. It mitigates latency bottlenecks by employing proactive latency-mitigation heuristics based on an application's access patterns. We present results using LambdaRAM to rapidly stride through remote multi-dimensional NASA Modeling, Analysis and Prediction (MAP) 2006 project datasets, based on time and geographical coordinates, to compute wind shear for cyclone and hurricane and tropical cyclone analysis. Our current experiments have demonstrated up to a 20-fold speedup in the computation of wind shear with LambdaRAM.\",\n \"Title: Early Experience on the Blue Gene/Q Supercomputing System\\nYear: 2013\\n\\nAbstract: The Argonne Leadership Computing Facility (ALCF) is home to Mira, a10 PF Blue Gene/Q (BG/Q) system. The BG/Q system is the third generation in Blue Gene architecture from IBM and like its predecessors combines system-on-chip technology with a proprietary interconnect (5-D torus). Each compute node has 16 augmented PowerPCA2 processor cores with support for simultaneous multithreading, 4-wide double precision SIMD, and different data prefetchingmechanisms. Mira offers several new opportunities for tuning and scaling scientific applications. This paper discusses our early experience with a subset of micro-benchmarks, MPI benchmarks, and a variety of science and engineering applications running at ALCF. Both performance and power are studied and results on BG/Q is compared with its predecessor BG/P. Several lessons gleaned from tuning applications on the BG/Q architecture for better performance and scalability are shared.\",\n \"Title: Modeling early galaxies using radiation hydrodynamics\\nYear: 2011\\n\\nAbstract: This simulation uses a flux-limited diffusion solver to explore the radiation hydrodynamics of early galaxies, in particular, the ionizing radiation created by Population III stars. At the time of this rendering, the simulation has evolved to a redshift of 3.5. The simulation volume is 11.2 comoving megaparsecs, and has a uniform grid of 10243 cells, with over 1 billion dark matter and star particles. This animation shows a combined view of the baryon density, dark matter density, radiation energy and emissivity from this simulation. The multi-variate rendering is particularly useful because is shows both the baryonic matter (\\\"normal\\\") and dark matter, and the pressure and temperature variables are properties of only the baryonic matter. Visible in the gas density are \\\"bubbles\\\", or shells, created by the radiation feedback from young stars. Seeing the bubbles from feedback provides confirmation of the physics model implemented. Features such as these are difficult to identify algorithmically, but easily found when viewing the visualization\",\n \"Title: GROPHECY: GPU performance projection from CPU code skeletons\\nYear: 2011\\n\\nAbstract: We propose GROPHECY, a GPU performance projection frame work that can estimate the performance benefit of GPU acceleration without actual GPU programming or hardware. Users need only to skeletonize pieces of CPU code that are targets for GPU acceleration. Code skeletons are automatically transformed in various ways to mimic tuned GPU codes with characteristics resembling real implementations. The synthesized characteristics are used by an existing analytical model to project GPU performance. The cost and benefit of GPU development can then be estimated according to the transformed code skeleton that yields the best projected performance. With GROPHECY, users can leap toward GPU acceleration only when the cost-benefit makes sense. The framework is validated using kernel benchmarks and data-parallel codes in legacy scientific applications. The measured performance of manually tuned codes deviates from the projected performance by 17% in geometric mean.\",\n \"Title: Poster: Evaluating Communication Performance in BlueGene/Q and Cray XE6 Supercomputers\\nYear: 2012\\n\\nAbstract: Evaluation of the communication performance in supercomputers Blue Gene/Q and Cray XE6 using MPI and lower level libraries are presented. MPI is widely used for to its simplicity, portability and straightforwardness, however it also introduces overhead that degrades communication performance. Some applications with performance constraints cannot tolerate that degradation. Recent supercomputers such as the Blue Gene/Q and CrayXE provide lower level communications libraries such as PAMI (Parallel Active Message Interface) and uGNI (User Generic Network Interface). Our experiments show that with different communications modes: one-sided, two-sided, inter-node, intra-node, we can achieve higher performance with certain message sizes. These results will enable us to develop a light-weight API for GLEAN which is a framework for I/O acceleration and in situ analysis, to get improved performance on these systems.\",\n \"Title: Accelerating Data Movement Leveraging End-System and Network Parallelism\\nYear: 2012\\n\\nAbstract: Data volumes produced by simulation, experimental and observational science is rapidly increasing. This data needs to be moved from its source to another resource for analysis, visualization and archival purposes. The destination resource could be either local or remote. The data intensive science is critically dependent upon the high-performance parallel file and storage end systems to read/write and high-speed networks to move their enormous data between local and remote computing and storage facilities. 100 Gigabit per second networks such as DOE's Advanced Network Initiative (ANI), Internet2's 100G network represent a major step forward in wide area network performance. Effective utilization of these networks requires substantial and pervasive parallelism, at the file system, end system, and network levels. Additional obstacles such as heterogeneity and time-varying conditions of network and end system arise that, if not adequately addressed, will render high performance storage and network systems extremely under-performed. In this paper, we propose a data movement system that dynamically and adaptively adjusts end systems and networks parallelisms in response to changing conditions of end systems and networks to sustain high-throughput for data transfers. We evaluate our system in multiple settings and show that (1) in a homogeneous configuration, the design can achieve better throughput for light and medium workload than GridFTP and achieve comparable throughput for heavy workload, (2) and in a heterogeneous configuration, the design can achieve several factors higher throughput for all workloads than GridFTP.\",\n \"Title: The Rails Toolkit - Enabling End-System Topology-Aware High End Computing\\nYear: 2008\\n\\nAbstract: We present a novel rails approach so that future e-Science applications can effectively exploit future system architectures, including multi-core and many-core architectures, multiple network cards, multiple graphical processing units and hybrid hierarchical memory architectures. We define \\\"rail\\\" as the co-scheduling of two or more of these resources. This approach enables creation of parallel multi-rails through every aspect of an end system: from processing on the multi- and many cores, to generation of multiple data flows and streaming over multi-lane network interface card (NIC) connected via a parallel interconnect. We describe a novel open-source multi-rail toolkit and the evaluation of end-system parameters that impact the efficiency of such multi-rail systems, including Interrupt, Memory, Thread and Core Affinities -- key properties for achieving scalable performance.\",\n \"Title: The global lambda visualization facility: an international ultra-high-definition wide-area visualization collaboratory\\nYear: 2006\\n\\nAbstract: The research outlined in this paper marks an initial global cooperative effort between visualization and collaboration researchers to build a persistent virtual visualization facility linked by ultra-high-speed optical networks. The goal is to enable the comprehensive and synergistic research and development of the necessary hardware, software and interaction techniques to realize the next generation of end-user tools for scientists to collaborate on the global Lambda Grid. This paper outlines some of the visualization research projects that were demonstrated at the iGrid 2005 workshop in San Diego, California.\",\n \"Title: Characterization And Understanding Machine-Specific Interconnects\\nYear: 2013\\n\\nAbstract: The use of efficient communication patterns is becoming increasingly important to utilize high concurrency and achieve high throughput and low latency of modern high-performance supercomputers. Efficacy is not only dictated by an application communication pattern, but also driven by the interconnect properties, the node architecture, and the quality of runtime communication libraries. Different systems require different tradeoffs with respect to communication mechanisms, which can impact the choice of application implementations. We use the in-house MPI benchmark suite to study the communication behavior of the interconnects and guide the performance tuning of scientific applications. We report the results of our investigation of four supercomputer systems located at ALCF, and present lessons learned from our experience.\",\n \"Title: Proactive Support for Large-Scale Data Exploration\\nYear: 2013\\n\\nAbstract: Computational science is generating increasingly unwieldy datasets created by complex and high-resolution simulations of physical, social, and economic systems. Traditional post processing of such large datasets requires high bandwidth to large storage resources. In situ processing approaches can reduce I/O requirements but steal processing cycles from the simulation and forsake interactive data exploration. The Fusion project aims to develop a new approach for exploring large-scale scientific datasets wherein the system actively assists the user in the data exploration process. A key component of the system is a software assistant that evaluates the stated and implied analysis goals of the scientist, observes the environment, models and proposes actions to be taken, and orchestrates the generation of analysis and visualization products for the user. These products are managed and made available to the scientist through an interactive space consisting of a database and a visual interface. The scientist sifts through and explores the available analysis products while indicating preferences that are translated into goals, completing the feedback loop that steers the assistant in its future actions.\",\n \"Title: Abstract: Evaluating Communication Performance in BlueGene/Q and Cray XE6 Supercomputers\\nYear: 2012\\n\\nAbstract: Summary form only given. Evaluation of the communication performance in supercomputers Blue Gene/Q and Cray XE6 using MPI and lower level libraries are presented. MPI is widely used for to its simplicity, portability and straightforwardness, however it also introduces overhead that degrades communication performance. Some applications with performance constraints cannot tolerate that degradation. Recent supercomputers such as the Blue Gene/Q and CrayXE provide lower level communications libraries such as PAMI (Parallel Active Message Interface) and uGNI (User Generic Network Interface). Our experiments show that with different communications modes: one-sided, two-sided, inter-node, intra-node we can always achieve higher performance with certain message sizes. These results will enable us to develop a GLEAN- light-weight API, which can be called directly from applications without passing through MPI to reduce/remove overhead.\",\n \"Title: LambdaBridge: A Scalable Architecture for Future Generation Terabit Applications\\nYear: 2006\\n\\nAbstract: LambdaGrid applications as typified by data-intensive collaborative visualization are likely to be the first users of terabit-level networking. This paper features a main enabler of collaborative visualization over LambdaGrid, the Scalable Adaptive Graphics Environment (SAGE) in particular, and anticipates the future needs of LambdaGrid applications in general. We present a scalable architecture called LambdaBridge to 'bridge' LambdaGrid applications with the terabit optical core networks. LambdaBridge will provision and control predictable- performance networks for end-systems (i.e. Grid clusters) using on-demand lambda/VLAN provisioning and end-system traffic shaping. The chief contribution of LambdaBridge is a deep understanding of how to synergistically bridge provisionable networks, end-systems, and future generation distributed terabit applications. This paper also introduces Scalable Visualcasting - a multicasting service for LambdaGrid that incorporates IP multicasting and optical multicasting.\",\n \"Title: Measuring Power Consumption on IBM Blue Gene/Q\\nYear: 2013\\n\\nAbstract: In addition to pushing what is possible computationally, state-of-the-art supercomputers are also pushing what is acceptable in terms of power consumption. Despite hardware manufacturers researching and developing efficient system components (e.g., processor, memory, etc.), the power consumption of a complete system remains an understudied research area. Because of the complexity and unpredictable workloads of these systems, estimating the power consumption of a full system is a nontrivial task.In this paper, we provide system-level power usage and temperature analysis of early access to Argonne's latest generation of IBM Blue Gene supercomputers, the Mira Blue Gene/Q system. The analysis is provided from the point of view of jobs running on the system. We describe the important implications these system level measurements have as well as the challenges they present. Using profiling code on benchmarks, we will also look at the new tools this latest generation of supercomputer provides and gauge their usefulness and how well they match up against the environmental data.\",\n \"Title: Model-Driven Multisite Workflow Scheduling\\nYear: 2013\\n\\nAbstract: Workflows continue to play an important role in expressing and deploying scientific applications. In recent years, a wide variety of computational sites have emerged with shared access to users. A user may not be able to complete a complex workflow at a single site. It is thus beneficial to run different tasks of a workflow on different sites. For such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources at multiple sites so that the workload is balanced among sites and the overhead is minimized in data transfer. The key challenge is that the data transfer rate among sites varies based on the network capacity and load. We propose a workflow scheduling technique that tackles the multi-site task distribution challenge by using data movement performance modeling. We applied this technique to schedule an earth observation science workflow over three sites. Executed via the Swift parallel scripting paradigm, we augmented its default schedule and improved the time-to-completion by up to 52%.\",\n \"Title: Ar-pin/pdc: flexible advance reservation of intradomain and interdomain lightpaths\\nYear: 2006\\n\\nAbstract: Grid is a computing architecture that consists of distributed clusters of computers interconnected by a network. Grid computing is used in a variety of data and compute-intensive scientific domains such as bioscience, nanotechnology, geoscience, high-energy physics. To facilitate the transportation of enormous (e.g. terabyte-sized) data-sets between Grid clusters, a new type of Grid computing architecture, called the LambdaGrid, has emerged. LambdaGrids are Grids that are interconnected by ultra-high-speed networks that can be directly controlled by applications. Typically the unit of control is a light path (often called a Lambda) in an optical network. In order for data-intensive applications to function efficiently, they need to be able to reserve enough bandwidth, through the allocation of these light paths. This thesis focuses on the problem of efficient scheduling of light paths between Grid clusters. Prior approaches use rigid scheduling schemes- i.e. resources are scheduled in terms of when the resources are needed and for how long. This thesis will show that contrary to obvious expectations, a flexible advance scheduling model can provide better overall resource utilization and user experience than a rigid scheduling scheme. In this thesis I propose a Flexible Advance Reservation Model (FARM) and describe how to apply this model to the cross-domain lightpath reservation problem by incorporating Routing and Wavelength Assignment algorithms. Next, I present the architecture, implementation and services of a coordinated Interdomain and Intradomain optical control plane called AR-PIN/PDC, which is capable of flexible advance reservations, and provides web services. The simulation results show that by relaxing the reservation time constraint, the acceptance rate and resource utilization can be improved dramatically. Through simulations, I also analyze the impact of advance reservations on immediate reservations and conclude that both AR and IR requests need admission control algorithms in order to let both types of reservations coexist and use resource properly. The AR-PIN/PDC software has been deployed in an international photonic testbed consisting of four domains. Over the testbed, I measure the components of end-to-end signaling latency during inter-domain reservation and claim processes. The results show that the major latency component during claim processes is the optical switching time and domain level parallelism can effectively reduce the claim latency. And the time slot granularity is the major factor affecting the reservation latency.\",\n \"Title: Application power profiling on IBM Blue Gene/Q.\\nYear: 2013\\n\\nAbstract: We describe our power profiling library called MonEQ, built on the IBM provided API.We integrate MonEQ into several benchmarks to show the data it produces.Applications have different power profiles based on usage of domains in node.There is no difference in power consumption in network for a given network topology.Scale can reduce power consumption but is far less important than execution time. The power consumption of state of the art supercomputers, because of their complexity and unpredictable workloads, is extremely difficult to estimate. Accurate and precise results, as are now possible with the latest generation of IBM Blue Gene/Q, are therefore a welcome addition to the landscape. Only recently have end users been afforded the ability to access the power consumption of their applications. However, just because it's possible for end users to obtain this data does not mean it's a trivial task. This emergence of new data is therefore not only understudied, but also not fully understood.In this paper, we describe our open source power profiling library called MonEQ, built on the IBM provided Environmental Monitoring (EMON) API. We show that it's lightweight, has extremely low overhead, is incredibly flexible, and has advanced features which end users can take advantage. We then integrate MonEQ into several benchmarks and show the data it produces and what analysis of this data can teach us. Going one step further we also describe how seemingly simple changes in scale or network topology can have dramatic effects on power consumption. To this end, previously well understood applications will now have new facets of potential analysis.\",\n \"Title: The first functional demonstration of optical virtual concatenation as a technique for achieving terabit networking\\nYear: 2006\\n\\nAbstract: The optical virtual concatenation (OVC) function of The Terabit LAN was demonstrated for the first time at the iGrid 2005 workshop in San Diego, California. The TERAbit-LAN establishes a lambda group path (LGP) for an application where the number of lambdas/L2 connections in a LGP can be specified by the application. Each LGP is logically treated as one end-to-end optical path, so during parallel transport, the LGP channels have no relative latency deviation. However, optical path diversity (e.g. restoration) can cause LGP relative latency deviations and negatively affect quality of service. OVC hardware developed by NTT compensates for relative latency deviations to achieve a virtual bulk transport for the Electronic Visualization Laboratory's (EVL) Scalable Adaptive Graphics Environment application.\",\n \"Title: Evaluating Power-Monitoring Capabilities on IBM Blue Gene/P and Blue Gene/Q\\nYear: 2012\\n\\nAbstract: Power consumption is becoming a critical factor as we continue our quest toward exascale computing. Yet, actual power utilization of a complete system is an insufficiently studied research area. Estimating the power consumption of a large scale system is a nontrivial task because a large number of components are involved and because power requirements are affected by the (unpredictable) workloads. Clearly needed is a power-monitoring infrastructure that can provide timely and accurate feedback to system developers and application writers so that they can optimize the use of this precious resource. Many existing large-scale installations do feature power-monitoring sensors, however, those are part of environmental- and health monitoring sub systems and were not designed with application level power consumption measurements in mind. In this paper, we evaluate the existing power monitoring of IBM Blue Gene systems, with the goal of understanding what capabilities are available and how they fare with respect to spatial and temporal resolution, accuracy, latency, and other characteristics. We find that with a careful choice of dedicated micro benchmarks, we can obtain meaningful power consumption data even on Blue Gene/P, where the interval between available data points is measured in minutes. We next evaluate the monitoring subsystem on Blue Gene/Q, and are able to study the power characteristics of FPU and memory subsystems of Blue Gene/Q. We find the monitoring subsystem capable of providing second-scale resolution of power data conveniently separated between node components with seven seconds latency. This represents a significant improvement in power monitoring infrastructure, and hope future systems will enable real-time power measurement in order to better understand application behavior at a finer granularity.\",\n \"Title: Vol-a-Tile - A Tool for Interactive Exploration of Large Volumetric Data on Scalable Tiled Displays\\nYear: 2004\\n\\nAbstract: We present the current state of Vol-a-Tile, an interactive tool for exploring large volumetric data on scalable tiled displays. Vol-a-Tile presents a variety of features employed by scientists at the Scripps Institution of Oceanography on data collected from the Anatomy of a Ridge-Axis Discontinuity seismic experiment. Hardware texture mapping and level-of-detail techniques provide interactivity. A high-performance network protocol is used to connect remote data sources over high-bandwidth photonic networks.\",\n \"Title: Multi-application inter-tile synchronization on ultra-high-resolution display walls\\nYear: 2010\\n\\nAbstract: Ultra-high-resolution tiled-display walls are typically driven by a cluster of computers. Each computer may drive one or more displays. Synchronization between the computers is necessary to ensure that animated imagery displayed on the wall appears seamless. Most tiled-display middleware systems are designed around the assumption that only a single application instance is running in the tiled display at a time. Therefore synchronization can be achieved with a simple solution such as a networked barrier. When a tiled display has to support multiple applications at the same time, however, the simple networked barrier approach does not scale. In this paper we propose and experimentally validate two synchronization algorithms to achieve low-latency, intertile synchronization for multiple applications with independently varying frame rates. The two-phase algorithm is more generally applicable to various highresolution tiled display systems. The one-phase algorithm provides superior results but requires support for the Network Time Protocol and is more CPU-intensive.\",\n \"Title: Multi-domain job coscheduling for leadership computing systems\\nYear: 2013\\n\\nAbstract: Current supercomputing centers usually deploy a large-scale compute system together with an associated data analysis or visualization system. Multiple scenarios have driven the demand that some associated jobs co-execute on different machines. We propose a multi-domain coscheduling mechanism, providing the ability to coordinate execution between jobs on multiple resource management domains without manual intervention. We have evaluated our mechanism based on real job traces from Intrepid and Eureka, the production Blue Gene/P system and a cluster with the largest GPU installation, deployed at Argonne National Laboratory. The experimental results show that coscheduling can be achieved with limited impact on system performance under varying workloads.\",\n \"Title: Scalable Parallel I/O on a Blue Gene/Q Supercomputer Using Compression, Topology-Aware Data Aggregation, and Subfiling\\nYear: 2014\\n\\nAbstract: In this paper, we propose an approach to improving the I/O performance of an IBM Blue Gene/Q supercomputing system using a novel framework that can be integrated into high performance applications. We take advantage of the system's tremendous computing resources and high interconnection bandwidth among compute nodes to efficiently exploit I/O bandwidth. This approach focuses on lossless data compression, topology-aware data movement, and subfiling. The efficacy of this solution is demonstrated using microbenchmarks and an application-level benchmark.\",\n \"Title: A generic high-performance method for deinterleaving scientific data\\nYear: 2013\\n\\nAbstract: High-performance and energy-efficient data management applications are a necessity for HPC systems due to the extreme scale of data produced by high fidelity scientific simulations that these systems support. Data layout in memory hugely impacts the performance. For better performance, most simulations interleave variables in memory during their calculation phase, but deinterleave the data for subsequent storage and analysis. As a result, efficient data deinterleaving is critical; yet, common deinterleaving methods provide inefficient throughput and energy performance. To address this problem, we propose a deinterleaving method that is high performance, energy efficient, and generic to any data type. To the best of our knowledge, this is the first deinterleaving method that 1) exploits data cache prefetching, 2) reduces memory accesses, and 3) optimizes the use of complete cache line writes. When evaluated against conventional deinterleaving methods on 105 STREAM standard micro-benchmarks, our method always improved throughput and throughput/watt on multi-core systems. In the best case, our deinterleaving method improved throughput up to 26.2x and throughput/watt up to 7.8x.\",\n \"Title: DIRAQ: scalable in situ data- and resource-aware indexing for optimized query performance\\nYear: 2014\\n\\nAbstract: Scientific data analytics in high-performance computing environments has been evolving along with the advancement of computing capabilities. With the onset of exascale computing, the increasing gap between compute performance and I/O bandwidth has rendered the traditional post-simulation processing a tedious process. Despite the challenges due to increased data production, there exists an opportunity to benefit from \\\"cheap\\\" computing power to perform query-driven exploration and visualization during simulation time. To accelerate such analyses, applications traditionally augment, post-simulation, raw data with large indexes, which are then repeatedly utilized for data exploration. However, the generation of current state-of-the-art indexes involves a compute- and memory-intensive processing, thus rendering them inapplicable in an in situ context. In this paper we propose DIRAQ, a parallel in situ , in network data encoding and reorganization technique that enables the transformation of simulation output into a query-efficient form, with negligible runtime overhead to the simulation run. DIRAQ's effective core-local, precision-based encoding approach incorporates an embedded compressed index that is 3---6 $$\\\\times $$ smaller than current state-of-the-art indexing schemes. Its data-aware index adjustmentation improves performance of group-level index layout creation by up to 35 % and reduces the size of the generated index by up to 27 %. Moreover, DIRAQ's in network index merging strategy enables the creation of aggregated indexes that speed up spatial-context query responses by up to $$10\\\\times $$ 10 versus alternative techniques. DIRAQ's topology-, data-, and memory-aware aggregation strategy results in efficient I/O and yields overall end-to-end encoding and I/O time that is less than that required to write the raw data with MPI collective I/O.\",\n \"Title: Large-Scale Simulations of Sky Surveys.\\nYear: 2014\\n\\nAbstract: Large-volume sky surveys have accessed the Universe's vast temporal and spatial expanse via a remarkable set of measurements. Interpretation of these cosmological observations requires large-scale numerical simulation and modeling. Addressing analysis workflow complexity is as important as running the underlying extreme-scale simulations. Here, the authors discuss how the Hardware/Hybrid Accelerated Cosmology Code framework addresses these challenges.\",\n \"Title: Profiling transport performance for big data transfer over dedicated channels\\nYear: 2015\\n\\nAbstract: The transfer of big data is increasingly supported by dedicated channels in high-performance networks. Transport protocols play a critical role in maximizing the link utilization of such high-speed connections. We propose a Transport Profile Generator (TPG) to characterize and enhance the end-to-end throughput performance of transport protocols. TPG automates the tuning of various transport-related parameters including socket options and protocol-specific configurations, and supports multiple data streams and multiple NIC-to-NIC connections. To instantiate the design of TPG, we use UDT as an example in the implementation and conduct extensive experiments of big data transfer over high-speed network channels to illustrate how existing transport protocols benefit from TPG in optimizing their performance.\",\n \"Title: Improving Multisite Workflow Performance Using Model-Based Scheduling\\nYear: 2014\\n\\nAbstract: Workflows play an important role in expressing and executing scientific applications. In recent years, a variety of computational sites and resources have emerged, and users often have access to multiple resources that are geographically distributed. These computational sites are heterogeneous in nature and performance of different tasks in a workflow varies from one site to another. Additionally, users typically have a limited resource allocation at each site. In such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources so that the workload is balanced among sites and the overhead is minimized in data transfer. Most existing systems either run the entire workflow in a single site or use naive approaches to distribute the tasks across sites or leave it to the user to optimize the allocation of tasks to distributed resources. This results in a significant loss in productivity for a scientist. In this paper, we propose a multi-site workflow scheduling technique that uses performance models to predict the execution time on different resources and dynamic probes to identify the achievable network throughput between sites. We evaluate our approach using real world applications in a distributed environment using the Swift distributed execution framework and show that our approach improves the execution time by up to 60% compared to the default schedule.\",\n \"Title: SKOPE: a framework for modeling and exploring workload behavior\\nYear: 2014\\n\\nAbstract: Understanding workload behavior plays an important role in performance studies. The growing complexity of applications and architectures has increased the gap among application developers, performance engineers, and hardware designers. To reduce this gap, we propose SKOPE, a SKeleton framework for Performance Exploration, that produces a descriptive model about the semantic behavior of a workload, which can infer potential transformations and help users understand how workloads may interact with and adapt to emerging hardware. SKOPE models can be shared, annotated, and studied by a community of performance engineers and system designers; they offer readability in the frontend and versatility in the backend. SKOPE can be used for performance analysis, tuning, and projection. We provide two example use cases. First, we project GPU performance from CPU code without GPU programming or accessing the hardware, and are able to automatically explore transformations and the projected best-achievable performance deviates from the measured by 18% on average. Second, we project the multi-node scaling trends of two scientific workloads, and are able to achieve a projection accuracy of 95%.\",\n \"Title: Toward optimizing disk-to-disk transfer on 100G networks\\nYear: 2013\\n\\nAbstract: The recent emergence of ultra high-speed networks up to 100 Gbps has posed numerous challenges and has led to many investigations on efficient protocols to saturate 100 Gbps links. However, end-to-end data transfers involve many compo-nents, not only protocols, affecting overall transfer performance. These components include a disk I10 subsystem, additional computation associated with data streams, and network adapter capacities. For example, achievable bandwidth by TCP may not be implementable if disk I/O or CPU becomes a bottleneck in end-to-end data transfer. In this paper, we first model all the system components involved in end-to-end data transfer as a graph. We then formulate the problem whose goal is to achieve maximum data transfer throughput using parallel data flows. Our contributions lie in how to optimize data transfers considering all the system components involved rather than in accurately modeling all the system components involved. Our proposed formulations and solutions are evaluated through experiments on the ESnet 100G testbed. The experimental results show that our approach is several times faster than Globus Online - 8x faster for datasets with many 10MB files and 3-4x faster for other datasets of larger size files.\",\n \"Title: Distributed multipath routing algorithm for data center networks\\nYear: 2014\\n\\nAbstract: Multipath routing has been studied in diverse contexts such as wide-area networks and wireless networks in order to minimize the finish time of data transfer or the latency of message sending. The fast adoption of cloud computing for various applications including high-performance computing applications has drawn more attention to efficient network utilization through adaptive or multipath routing methods. However, the previous studies have not exploited multiple paths in an optimized way while scaling well with a large number of hosts for some reasons such as high time complexity of algorithms. In this paper, we propose a scalable distributed flow scheduling algorithm that can exploit multiple paths in data center networks. We develop our algorithm based on linear programming and evaluate the algorithm in FatTree network topologies, one of several advanced data center network topologies. The results show that the distributed algorithm performs much better than the centralized algorithm in terms of running time and is comparable to the centralized algorithm within 10% increased finish time in terms of data transfer time.\",\n \"Title: Cluster-to-cluster data transfer with data compression over wide-area networks\\nYear: 2015\\n\\nAbstract: The recent emergence of ultra high-speed networks up to 100 Gb/s has posed numerous challenges and has led to many investigations on efficient protocols to saturate 100 Gb/s links. However, end-to-end data transfers involve many components, not only protocols, affecting overall transfer performance. These components include disk I/O subsystem, additional computation associated with data streams, and network adapters. For example, achievable bandwidth by TCP may not be implementable if disk I/O or CPU becomes a bottleneck in end-to-end data transfer. In this paper, we first model all the system components involved in end-to-end data transfer as a graph. We then formulate the problem whose goal is to achieve maximum data transfer throughput using parallel data flows. We also propose a variable data flow GridFTP XIO stack to improve data transfer with data compression. Our contributions lie in how to optimize data transfers considering all the system components involved rather than in accurately modeling all the system components involved. Our proposed formulations and solutions are evaluated through experiments on the ESnet 100G testbed and a wide-area cluster-to-cluster testbed. The experimental results on the ESnet 100G testbed show that our approach is several times faster than Globus Online-8 í¿ faster for datasets with many 10¿MB files and 3-4 í¿ faster for other datasets of larger size files. The experimental results on the cluster-to-cluster testbed show that our variable data flow approach is up to 4 í¿ faster than a normal cluster data transfer. We model all the system components involved in end-to-end data transfer as a graph.We formulate the problem to optimize data transfer throughput using parallel flows.We propose a novel software I/O stack with variable parallel data flows per layer.Optimized parallel data flows improve overall data transfer throughput.The novel I/O stack with data compression alleviates network bottleneck situations.\",\n \"Title: Improving sparse data movement performance using multiple paths on the Blue Gene/Q supercomputer.\\nYear: 2016\\n\\nAbstract: •We adapt Ford–Fulkerson’s algorithm to find multiple disjoint paths to move data.•We realize multi-path data movement by introducing intermediate nodes to the paths.•We leverage routing policies to reduce the number of intermediate nodes.•We implement pipelined data movement with the Parallel Active Message Interface.\",\n \"Title: Workflow performance improvement using model-based scheduling over multiple clusters and clouds\\nYear: 2016\\n\\nAbstract: In recent years, a variety of computational sites and resources have emerged, and users often have access to multiple resources that are distributed. These sites are heterogeneous in nature and performance of different tasks in a workflow varies from one site to another. Additionally, users typically have a limited resource allocation at each site capped by administrative policies. In such cases, judicious scheduling strategy is required in order to map tasks in the workflow to resources so that the workload is balanced among sites and the overhead is minimized in data transfer. Most existing systems either run the entire workflow in a single site or use naïve approaches to distribute the tasks across sites or leave it to the user to optimize the allocation of tasks to distributed resources. This results in a significant loss in productivity. We propose a multi-site workflow scheduling technique that uses performance models to predict the execution time on resources and dynamic probes to identify the achievable network throughput between sites. We evaluate our approach using real world applications using the Swift parallel and distributed execution framework. We use two distinct computational environments-geographically distributed multiple clusters and multiple clouds. We show that our approach improves the resource utilization and reduces execution time when compared to the default schedule.\",\n \"Title: Multipath Load Balancing for M × N Communication Patterns on the Blue Gene/Q Supercomputer Interconnection Network\\nYear: 2015\\n\\nAbstract: Achievable networking performance of applications in a supercomputer depends on the exact combination of the communication patterns of the applications and the routing algorithms used by the supercomputer. In order to achieve the highest networking performance for the applications the routing algorithms need to be designed optimally for those communication patterns. However, while communication patterns usually have a wide variation from application to application and even from phase to phase in an application, routing algorithms have a limited variation and usually are optimized for typical communication patterns. This results in high networking performance for favored communication patterns but low networking performance for others. In this paper we present approaches for improving networking performance by rebalancing load on physical links on the Blue Gene Q supercomputer. We realize our approaches in a framework called OPTIQ and demonstrate the efficacy of our framework via a set of benchmarks. Our results show that we can achieve 30% higher throughput on experiment with data and patterns from a real application. The improvement can be up to several times higher throughput than default MPI_Alltoallv used in the Blue Gene Q supercomputer for certain communication patterns.\",\n \"Title: Large-scale co-visualization for LAMMPS using vl3\\nYear: 2015\\n\\nAbstract: In this poster we propose to interconnect LAMMPS and vl3, our parallel framework for large-scale visualization and analysis. The goal is co-visualization and exploration at interactive frame rates of large-scale atomistic simulations. We describe the architecture of the proposed system, as well as a preliminary implementation that runs on GPU-based visualization clusters.\",\n \"Title: Streaming ultra high resolution images to large tiled display at nearly interactive frame rate with vl3\\nYear: 2015\\n\\nAbstract: Visualization of large-scale simulations running on supercomputers requires ultra-high resolution images to capture important features in the data. In this work, we present a system for streaming ultra-high resolution images from a visualization cluster to a remote tiled display at nearly interactive frame rates. vl3, a modular framework for large scale data visualization and analysis, provides the backbone of our implementation. With this system we are able to stream over the network volume renderings of a 20483 voxel dataset at a resolution of 6144×3072 pixels with a frame rate of approximately 3.3 frames per second.\",\n \"Title: Optimal scheduling of in-situ analysis for large-scale scientific simulations\\nYear: 2015\\n\\nAbstract: Today's leadership computing facilities have enabled the execution of transformative simulations at unprecedented scales. However, analyzing the huge amount of output from these simulations remains a challenge. Most analyses of this output is performed in post-processing mode at the end of the simulation. The time to read the output for the analysis can be significantly high due to poor I/O bandwidth, which increases the end-to-end simulation-analysis time. Simulation-time analysis can reduce this end-to-end time. In this work, we present the scheduling of in-situ analysis as a numerical optimization problem to maximize the number of online analyses subject to resource constraints such as I/O bandwidth, network bandwidth, rate of computation and available memory. We demonstrate the effectiveness of our approach through two application case studies on the IBM Blue Gene/Q system.\",\n \"Title: On-demand unstructured mesh translation for reducing memory pressure during in situ analysis\\nYear: 2013\\n\\nAbstract: When coupling two different mesh-based codes, for example with in situ analytics, the typical strategy is to explicitly copy data (deep copy) from one implementation to another, doing translation in the process. This is necessary because codes usually do not share data model interfaces or implementations. The drawback is that data duplication results in an increased memory footprint for the coupled code. An alternative strategy, which we study in this paper, is to share mesh data through on-demand, fine-grained, run-time data model translation. This saves memory, which is an increasingly scarce resource at exascale, for the increased use of in situ analysis and decreasing memory per core. We study the performance of our method compared against a deep copy with in situ analysis at scale.\",\n \"Title: Route-aware independent MPI I/O on the blue gene/Q.\\nYear: 2015\\n\\nAbstract: Scalable high-performance I/O is crucial for application performance on large-scale systems. With the growing complexity of the system interconnects, it has become important to consider the impact of network contention on I/O performance because the I/O messages traverse several hops in the interconnect before reaching the I/O nodes or the file system. In this work, we present a route-aware and load-aware algorithm to modify existing bridge node assignment in the Blue Gene/Q (BG/Q) supercomputer. We reduce the network contention and reduce the write time by an average of 60% over the default independent I/O and by 20% over collective I/O on up to 8192 nodes on the Mira BG/Q system. Our algorithm routes 1.4x fewer messages through the bridge nodes which connect to the I/O nodes on the BG/Q.\",\n \"Title: Modeling Cooperative Threads To Project Gpu Performance For Adaptive Parallelism\\nYear: 2015\\n\\nAbstract: Most accelerators, such as graphics processing units (GPUs) and vector processors, are particularly suitable for accelerating massively parallel workloads. On the other hand, conventional workloads are developed for multi-core parallelism, which often scale to only a few dozen OpenMP threads. When hardware threads significantly outnumber the degree of parallelism in the outer loop, programmers are challenged with efficient hardware utilization. A common solution is to further exploit the parallelism hidden deep in the code structure. Such parallelism is less structured: parallel and sequential loops may be imperfectly nested within each other; neighboring inner loops may exhibit different concurrency patterns (e.g. reduction vs. forall), yet have to be parallelized in the same parallel section. Many input-dependent transformations have to be explored. A programmer often employs a larger group of hardware threads to cooperatively walk through a smaller outer loop partition and adaptively exploit any encountered parallelism. This process is time-consuming and error-prone, yet the risk of gaining little or no performance remains high for such workloads.To reduce risk and guide implementation, we propose a technique to model workloads with limited parallelism that can automatically explore and evaluate transformations involving cooperative threads. Eventually, our framework projects the best achievable performance and the most promising transformations without implementing GPU code or using physical hardware. We envision our technique to be integrated into future compilers or optimization frameworks for autotuning.\",\n \"Title: Large-Scale Parallel Visualization of Particle-Based Simulations using Point Sprites and Level-Of-Detail.\\nYear: 2015\\n\\nAbstract: Recent large-scale particle-based simulations are generating vast amounts of data posing a challenge to visualization algorithms. One possibility for addressing this challenge is to map particles into a regular grid for volume rendering, which carries the disadvantages of inefficient use of memory and undesired losses of dynamic range. As an alternative, we propose a method to efficiently visualize these massive particle datasets using point rendering techniques with neither loss of dynamic range nor memory overheads. In addition, a hierarchical reorganization of the data is desired to deliver meaningful visual representations of a large number of particles in a limited number of pixels, preserving point locality and also helping achieve interactive frame rates. In this paper, we present a framework for parallel rendering of large-scale particle data sets combining point sprites and z-ordering. The latter is used to create a multi level representation of the data which helps improving frame rates. Performance and scalability are evaluated on a GPU-based visualization cluster, scaling up to 128 GPUs. Results using particle datasets of up to 32 billion particles are shown.\",\n \"Title: Improving Data Movement Performance for Sparse Data Patterns on the Blue Gene/Q Supercomputer\\nYear: 2014\\n\\nAbstract: In-situ analysis has been proposed as a promising solution to glean faster insight and to reduce the amount of data written out to storage. A critical challenge here is that the reduced dataset needed to visualize a specific region of interest as the simulation is running is typically held on a subset of the nodes and needs to be written out to storage. Coupled multiphysics simulations also produce a sparse data pattern wherein data movement occurs among a subset of nodes. We evaluate the performance of these data patterns and propose several mechanisms for improving performance. Our mechanisms introduce intermediate nodes to implement multiple paths to transfer data on top of default routing algorithms and utilize topology-aware data aggregation to avoid shared bottleneck links. The efficacy of our solutions is evaluated through microbenchmarks and application benchmarks on an IBM Blue Gene/Q system scaling up to 131,072 compute cores. The results show that our algorithms achieve up to a 2X improvement in achievable throughput compared to the default mechanisms.\",\n \"Title: Improving Communication Throughput by Multipath Load Balancing on Blue Gene/Q.\\nYear: 2015\\n\\nAbstract: Achievable networking performance of applications in a supercomputer depends on the exact combination of the communication patterns of the applications and the routing algorithms used by the supercomputer. In order to achieve the highest networking performance for the applications, the routing algorithms need to be designed optimally for those communication patterns. However, while communication patterns usually vary from application to application and even from phase to phase in an application, routing algorithms have limited variation and usually are optimized for typical communication patterns. This results in high networking performance for some communication patterns. In this paper we present approaches for improving communication performance by using multiple paths and re-balancing load on physical links on the Blue Gene/Q supercomputer. We realize our approaches in a framework called OPTIQ and demonstrate the efficacy of our framework via a set of benchmarks. Our results show that we can achieve 43 -- 67% higher throughput on average from 91 experiments, and can achieve higher throughput than default MPI_Alltoallv used for certain communication patterns.\",\n \"Title: TECA: Petascale Pattern Recognition for Climate Science\\nYear: 2015\\n\\nAbstract: Climate Change is one of the most pressing challenges facing humanity in the 21st century. Climate simulations provide us with a unique opportunity to examine effects of anthropogenic emissions. High-resolution climate simulations produce \\\\\\\"Big Data\\\\\\\": contemporary climate archives are $$\\\\\\\\approx 5PB$$ in size and we expect future archives to measure on the order of Exa-Bytes. In this work, we present the successful application of TECA Toolkit for Extreme Climate Analysis framework, for extracting extreme weather patterns such as Tropical Cyclones, Atmospheric Rivers and Extra-Tropical Cyclones from TB-sized simulation datasets. TECA has been run at full-scale on Cray XE6 and IBM BG/Q systems, and has reduced the runtime for pattern detection tasks from years to hours. TECA has been utilized to evaluate the performance of various computational models in reproducing the statistics of extreme weather events, and for characterizing the change in frequency of storm systems in the future.\",\n \"Title: In Situ Methods, Infrastructures, and Applications on High Performance Computing Platforms.\\nYear: 2016\\n\\nAbstract: The considerable interest in the high performance computing (HPC) community regarding analyzing and visualization data without first writing to disk, i.e., in situ processing, is due to several factors. First is an I/O cost savings, where data is analyzed/visualized while being generated, without first storing to a filesystem. Second is the potential for increased accuracy, where fine temporal sampling of transient analysis might expose some complex behavior missed in coarse temporal sampling. Third is the ability to use all available resources, CPU's and accelerators, in the computation of analysis products. This STAR paper brings together researchers, developers and practitioners using in situ methods in extreme-scale HPC with the goal to present existing methods, infrastructures, and a range of computational science and engineering applications using in situ analysis and visualization.\",\n \"Title: A data driven scheduling approach for power management on HPC systems.\\nYear: 2016\\n\\nAbstract: Modern schedulers running on HPC systems traditionally consider the number of resources and the time requested for each job that is to be executed when making scheduling decisions. Until recently this has been sufficient, however as systems get larger, other metrics like power consumption become necessary to ensure system stability. In this paper, we propose a data driven scheduling approach for controlling the power consumption of the entire system under any user defined budget. Here, \\\\\\\"data driven\\\\\\\" means that our approach actively observes, analyzes, and assesses power behaviors of the system and user jobs to guide scheduling decisions for power management. This design is based on the key observation that HPC jobs have distinct power profiles. Our work contains an empirical analysis of workload power characteristics on a production system, dynamic learner to estimate the job power profile for scheduling, and an online power-aware scheduler for managing the overall system power. Using real workload traces, we demonstrate that our design effectively controls system power consumption while minimizing the impact on system utilization.\",\n \"Title: Performance analysis, design considerations, and applications of extreme-scale in situ infrastructures.\\nYear: 2016\\n\\nAbstract: A key trend facing extreme-scale computational science is the widening gap between computational and I/O rates, and the challenge that follows is how to best gain insight from simulation data when it is increasingly impractical to save it to persistent storage for subsequent visual exploration and analysis. One approach to this challenge is centered around the idea of in situ processing, where visualization and analysis processing is performed while data is still resident in memory. This paper examines several key design and performance issues related to the idea of in situ processing at extreme scale on modern platforms: scalability, overhead, performance measurement and analysis, comparison and contrast with a traditional post hoc approach, and interfacing with simulation codes. We illustrate these principles in practice with studies, conducted on large-scale HPC platforms, that include a miniapplication and multiple science application codes, one of which demonstrates in situ methods in use at greater than 1M-way concurrency.\",\n \"Title: Optimal execution of co-analysis for large-scale molecular dynamics simulations.\\nYear: 2016\\n\\nAbstract: The analysis of scientific simulation data enables scientists to derive insights from their simulations. This analysis of the simulation output can be performed at the same execution site as the simulation using the same resources or can be done at a different site. The optimal output frequency is challenging to decide and is often chosen empirically. We propose a mathematical formulation for choosing the optimal frequency of data transfer for analysis and the feasibility of performing the analysis, under the given resource constraints such as network bandwidth, disk space, available memory, and computation time. We propose formulations for two cases of co-analysis - local and remote. We consider various analyses features such as computation time, input data and memory requirement, importance of the analysis and minimum frequency required for performing the analysis. We demonstrate the effectiveness of our approach using molecular dynamics applications on the Mira and Edison supercomputers.\",\n \"Title: Data movement optimizations for independent MPI I/O on the Blue Gene/Q.\\nYear: 2017\\n\\nAbstract: •We propose algorithm to route data to closer IO nodes and reduce network congestion.•Developed a route-aware strategy to modify existing bridge node assignments in BG/Q.•Our algorithm reduces write times by 60% on average than default independent I/O.•The default independent MPI I/O routes 1.4x more I/O messages than our approach.•By intra-node aggregation, our modified independent I/O obtains 10.5 GB/s bandwidth.\",\n \"Title: Topology-Aware Data Aggregation for Intensive I/O on Large-Scale Supercomputers.\\nYear: 2016\\n\\nAbstract: Reading and writing data efficiently from storage systems is critical for high performance data-centric applications. These I/O systems are being increasingly characterized by complex topologies and deeper memory hierarchies. Effective parallel I/O solutions are needed to scale applications on current and future supercomputers. Data aggregation is an efficient approach consisting of electing some processes in charge of aggregating data from a set of neighbors and writing the aggregated data into storage. Thus, the bandwidth use can be optimized while the contention is reduced. In this work, we take into account the network topology for mapping aggregators and we propose an optimized buffering system in order to reduce the aggregation cost. We validate our approach using micro-benchmarks and the I/O kernel of a large-scale cosmology simulation. We show improvements up to 15X faster for I/O operations compared to a standard implementation of MPI I/O.\",\n \"Title: Early Investigations into Using a Remote RAM Pool with the vl3 Visualization Framework.\\nYear: 2016\\n\\nAbstract: This paper discusses early efforts to integrate the RAN remote memory technology into the vl3 volume rendering framework. We successfully demonstrate this integration, achieving 73% of the theoretical hardware maximum with minimal variation.\",\n \"Title: Parallel distributed, GPU-accelerated, advanced lighting calculations for large-scale volume visualization\\nYear: 2016\\n\\nAbstract: The benefits of applying advanced illumination models to volume visualization have been demonstrated by many researchers. For a parallel distributed, GPU computing environment, however, there is no efficient algorithm for scalable global illumination calculations. This paper presents a parallel, data-distributed and GPU-accelerated algorithm for volume rendering with advanced lighting. Our approach features tunable soft shadows for enhancing perception of complex spatial structures and relationships. For lighting calculations, our design effectively avoids data exchange among GPUs. Performance evaluation on a GPU cluster using up to 128 GPUs shows scalable rendering performance, with both the number of GPUs and volume data size.\",\n \"Title: Analytical Performance Modeling and Validation of Intel's Xeon Phi Architecture.\\nYear: 2017\\n\\nAbstract: Modeling the performance of scientific applications on emerging hardware plays a central role in achieving extreme-scale computing goals. Analytical models that capture the interaction between applications and hardware characteristics are attractive because even a reasonably accurate model can be useful for performance tuning before the hardware is made available. In this paper, we develop a hardware model for Intel's second-generation Xeon Phi architecture code-named Knights Landing (KNL) for the SKOPE framework. We validate the KNL hardware model by projecting the performance of minibenchmarks and application kernels. The results show that our KNL model can project the performance with prediction errors of 10% to 20%. The hardware model also provides informative recommendations for code transformations and tuning.\",\n \"Title: A distributed graph approach for pre-processing linked RDF data using supercomputers\\nYear: 2017\\n\\nAbstract: Efficient RDF, graph based queries are becoming more pertinent based on the increased interest in data analytics and its intersection with large, unstructured but connected data. Many commercial systems have adopted distributed RDF graph systems in order to handle increasing dataset sizes and complex queries. This paper introduces a distribute graph approach to pre-processing linked data. Instead of traversing the memory graph, our system indexes pre-processed join elements that are organized in a graph structure. We analyze the Dbpedia data-set (derived from the Wikipedia corpus) and compare our access method to the graph traversal access approach which we also devise. Results show from our experiments that the distributed, pre-processed graph approach to accessing linked data is faster than the traversal approach over a specific range of linked queries.\",\n \"Title: PoLiMEr: An Energy Monitoring and Power Limiting Interface for HPC Applications\\nYear: 2017\\n\\nAbstract: Power and energy consumption are now key design concerns in HPC. To develop software that meets power and energy constraints, scientific application developers must have a reliable way to measure these values and relate them to application-specific events. Scientists face two challenges when measuring and controlling power: (1) diversity---power and energy measurement interfaces differ between vendors---and (2) distribution---power measurements of MPI simulations should be unaffected by the mapping of MPI processes to physical hardware nodes. While some prior work defines standardized software interfaces for power management, these efforts do not support distributed environments. The result is that the current state-of-the-art requires scientists interested in power optimization to write tedious, error-prone application-and system-specific code. To make power measurement and management easier for scientists, we propose PoLiMEr, a user-space library that supports fine-grained application-level power monitoring and capping. We evaluate PoLiMEr by deploying it on Argonne National Laboratory's Theta system and using it to measure and cap power, scaling the performance and power of several applications on up to 1024 nodes. We find that PoLiMEr requires only a few additional lines of code, but easily allows users to detect energy anomalies, apply power caps, and evaluate Theta's unique architectural features.\",\n \"Title: TAPIOCA: An I/O Library for Optimized Topology-Aware Data Aggregation on Large-Scale Supercomputers\\nYear: 2017\\n\\nAbstract: Reading and writing data efficiently from storage system is necessary for most scientific simulations to achieve good performance at scale. Many software solutions have been developed to decrease the I/O bottleneck. One well-known strategy, in the context of collective I/O operations, is the two-phase I/O scheme. This strategy consists of selecting a subset of processes to aggregate contiguous pieces of data before performing reads/writes. In this paper, we present TAPIOCA, an MPI-based library implementing an efficient topology-aware two-phase I/O algorithm. We show how TAPIOCA can take advantage of double-buffering and one-sided communication to reduce as much as possible the idle time during data aggregation. We also introduce our cost model leading to a topology-aware aggregator placement optimizing the movements of data. We validate our approach at large scale on two leadership-class supercomputers: Mira (IBM BG/Q) and Theta (Cray XC40). We present the results obtained with TAPIOCA on a micro-benchmark and the I/O kernel of a large-scale simulation. On both architectures, we show a substantial improvement of I/O performance compared with the default MPI I/O implementation. On BG/Q+GPFS, for instance, our algorithm leads to a performance improvement by a factor of twelve while on the Cray XC40 system associated with a Lustre filesystem, we achieve an improvement of four.\",\n \"Title: Scalable In situ Analysis of Molecular Dynamics Simulations.\\nYear: 2017\\n\\nAbstract: Analysis of scientific simulation data enables scientists to glean insight from simulations. In situ analysis, which can be simultaneously executed with the simulation, mitigates I/O bottlenecks and can accelerate discovery of new phenomena. However, in typical modes of operation, this requires either stalling simulation during analysis phase or transferring data for analysis. We study the scalability challenges of time- and space-shared modes of analyzing large-scale molecular dynamics simulations. We also propose topology-aware mapping for simulation and analysis. We demonstrate the benefits of our approach using LAMMPS code on two supercomputers.\",\n \"Title: Toward Scalable and Asynchronous Object-Centric Data Management for HPC\\nYear: 2018\\n\\nAbstract: Emerging high performance computing (HPC) systems are expected to be deployed with an unprecedented level of complexity due to a deep system memory and storage hierarchy. Efficient and scalable methods of data management and movement through this hierarchy is critical for scientific applications using exascale systems. Moving toward new paradigms for scalable I/O in the extreme-scale era, we introduce novel object-centric data abstractions and storage mechanisms that take advantage of the deep storage hierarchy, named Proactive Data Containers (PDC). In this paper, we formulate object-centric PDCs and their mappings in different levels of the storage hierarchy. PDC adopts a client-server architecture with a set of servers managing data movement across storage layers. To demonstrate the effectiveness of the proposed PDC system, we have measured performance of benchmarks and I/O kernels from scientific simulation and analysis applications using PDC programming interface, and compared the results with existing highly tuned I/O libraries. Using asynchronous I/O along with data and metadata optimizations, PDC demonstrates up to 23× speedup over HDF5 and PLFS in writing and reading data from a plasma physics simulation. PDC achieves comparable performance with HDF5 and PLFS in reading and writing data of a single timestep at small scale, and outperforms them at a scale of larger than 10K cores. In contrast to existing storage systems, PDC offers user-space data management with the flexibility to allocate the number of PDC servers depending on the workload.\",\n \"Title: Optimizing Data Aggregation by Leveraging the Deep Memory Hierarchy on Large-scale Systems.\\nYear: 2018\\n\\nAbstract: Effective data aggregation is of paramount importance for data-centric applications in order to improve data movement for I/O or to facilitate complex workflows, such as in-situ analysis, as well as coupling models and data for multi-physics. A key challenge for data aggregation in current and upcoming architectures is the heterogeneity of memory and storage systems (including DRAM, MCDRAM, NVRAM or parallel file system). One has to take advantage of this hierarchy and the characteristics of each tier to achieve improved performance at scale. In this paper, we present a topology and memory-aware data movement library performing data aggregation on large-scale systems. We first detail our hardware abstraction layer to accomplish code and performance portability on various platforms. Next, we present a cost model taking into account the system interconnect and the memory properties to determine an appropriate location for aggregating data. We also describe how we have implemented a data aggregation mechanism through the read algorithm. Finally, we show how we can improve data movement on a visualization cluster and a leadership-class supercomputer up to 16K processes with a benchmark and two typical I/O kernels. Particularly, we demonstrate how our approach can decrease the I/O time of a classic workflow by 26%.\",\n \"Title: Topology-aware space-shared co-analysis of large-scale molecular dynamics simulations.\\nYear: 2018\\n\\nAbstract: Analysis of scientific simulation data can be concurrently executed with simulation either in time- or space-shared mode. This mitigates the I/O bottleneck, however it results in either stalling the simulation for performing the analysis or transferring data for analysis. In this paper, we improve the throughput of space-shared in situ analysis of large-scale simulations by topology-aware mapping and optimal process decomposition. We propose node interconnect topology-aware process placement for simulation and analysis to reduce the data movement time. We also present an integer linear program for optimal 3D decompositions of simulation and analysis processes. We demonstrate our approach using molecular dynamics simulation on Mira, Cori and Theta supercomputers. Our mapping schemes, combined with optimal 3D process decomposition and code optimizations resulted in up to 30% lower execution times for space-shared in situ analysis than the default approach. Our mappings also reduce MPI collective I/O times by 10–40%.\",\n \"Title: libIS - a lightweight library for flexible in transit visualization.\\nYear: 2018\\n\\nAbstract: As simulations grow in scale, the need for in situ analysis methods to handle the large data produced grows correspondingly. One desirable approach to in situ visualization is in transit visualization. By decoupling the simulation and visualization code, in transit approaches alleviate common difficulties with regard to the scalability of the analysis, ease of integration, usability, and impact on the simulation. We present libIS, a lightweight, flexible library which lowers the bar for using in transit visualization. Our library works on the concept of abstract regions of space containing data, which are transferred from the simulation to the visualization clients upon request, using a client-server model. We also provide a SENSEI analysis adaptor, which allows for transparent deployment of in transit visualization. We demonstrate the flexibility of our approach on batch analysis and interactive visualization use cases on different HPC resources.\",\n \"Title: A Visual Analytics System for Optimizing Communications in Massively Parallel Applications\\nYear: 2017\\n\\nAbstract: Current and future supercomputers have tens of thousands of compute nodes interconnected with high-dimensional networks and complex network topologies for improved performance. Application developers are required to write scalable parallel programs in order to achieve high throughput on these machines. Application performance is largely determined by efficient inter-process communication. A common way to analyze and optimize performance is through profiling parallel codes to identify communication bottlenecks. However, understanding gigabytes of profiled at a is not a trivial task. In this paper, we present a visual analytics system for identifying the scalability bottlenecks and improving the communication efficiency of massively parallel applications. Visualization methods used in this system are designed to comprehend large-scale and varied communication patterns on thousands of nodes in complex networks such as the 5D torus and the dragonfly. We also present efficient rerouting and remapping algorithms that can be coupled with our interactive visual analytics design for performance optimization. We demonstrate the utility of our system with several case studies using three benchmark applications on two leading supercomputers. The mapping suggestion from our system led to 38% improvement in hop-bytes for Mini AMR application on 4,096 MPI processes.\",\n \"Title: Benchmarking Machine Learning Methods for Performance Modeling of Scientific Applications\\nYear: 2018\\n\\nAbstract: Performance modeling is an important and active area of research in high-performance computing (HPC). It helps in better job scheduling and also improves overall performance of coupled applications. Sufficiently rich analytical models are challenging to develop, however, because of interactions between different node components, network topologies, job interference, and application complexity. When analytical performance models become restrictive because of application dynamics and/or multicomponent interactions, machine-learning-based performance models can be helpful. While machine learning (ML) methods do not require underlying system or application knowledge, they are efficient in learning the unknown interactions of the application and system parameters empirically using application runs. We present a benchmark study in which we evaluate eleven machine learning methods for modeling the performance of four representative scientific applications that are irregular and with skewed domain configurations on four leadership-class HPC platforms. We assess the impact of feature engineering, size of training set, modern hardware platforms, transfer learning, extrapolation on the prediction accuracy, and training and inference times. We find that bagging, boosting, and deep neural network ML methods are promising approaches with median \\n<tex xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">$R^{2}$</tex>\\n values greater than 0.95 and these methods do not require feature engineering. We demonstrate that cross-platform performance prediction can be improved significantly using transfer learning with deep neural networks.\",\n \"Title: A Benchmarking Study to Evaluate Apache Spark on Large-Scale Supercomputers.\\nYear: 2019\\n\\nAbstract: As dataset sizes increase, data analysis tasks in high performance computing (HPC) are increasingly dependent on sophisticated dataflows and out-of-core methods for efficient system utilization. In addition, as HPC systems grow, memory access and data sharing are becoming performance bottlenecks. Cloud computing employs a data processing paradigm typically built on a loosely connected group of low-cost computing nodes without relying upon shared storage and/or memory. Apache Spark is a popular engine for large-scale data analysis in the cloud, which we have successfully deployed via job submission scripts on production clusters. In this paper, we describe common parallel analysis dataflows for both Message Passing Interface (MPI) and cloud based applications. We developed an effective benchmark to measure the performance characteristics of these tasks using both types of systems, specifically comparing MPI/C-based analyses with Spark. The benchmark is a data processing pipeline representative of a typical analytics framework implemented using map-reduce. In the case of Spark, we also consider whether language plays a role by writing tests using both Python and Scala, a language built on the Java Virtual Machine (JVM). We include performance results from two large systems at Argonne National Laboratory including Theta, a Cray XC40 supercomputer on which our experiments run with 65,536 cores (1024 nodes with 64 cores each). The results of our experiments are discussed in the context of their applicability to future HPC architectures. Beyond understanding performance, our work demonstrates that technologies such as Spark, while typically aimed at multi-tenant cloud-based environments, show promise for data analysis needs in a traditional clustering/supercomputing environment.\",\n \"Title: Scaling Distributed Training of Flood-Filling Networks on HPC Infrastructure for Brain Mapping.\\nYear: 2019\\n\\nAbstract: Mapping all the neurons in the brain requires automatic reconstruction of entire cells from volume electron microscopy data. The flood-filling networks (FFN) architecture can achieve leading performance. However, the training of the network is computationally very expensive. In order to reduce the training time, we implemented synchronous and data-parallel distributed training using the Horovod framework on top of the published FFN code. We demonstrated the scaling of FFN training up to 1024 Intel Knights Landing (KNL) nodes at Argonne Leadership Computing Facility. We investigated the training accuracy with different optimizers, learning rates, and optional warm-up periods. We discovered that square root scaling for learning rate works best beyond 16 nodes, which is contrary to the case of smaller number of nodes, where linear learning rate scaling with warm-up performs the best. Our distributed training reaches 95% accuracy in approximately 4.5 hours on 1024 KNL nodes using Adam optimizer.\",\n \"Title: A Machine Learning Workflow For Molecular Analysis: Application To Melting Points\\nYear: 2020\\n\\nAbstract: Computational tools encompassing integrated molecular prediction, analysis, and generation are key for molecular design in a variety of critical applications. In this work, we develop a workflow for molecular analysis (MOLAN) that integrates an ensemble of supervised and unsupervised machine learning techniques to analyze molecular data sets. The MOLAN workflow combines molecular featurization, clustering algorithms, uncertainty analysis, low-bias dataset construction, high-performance regression models, graph-based molecular embeddings and attribution, and a semi-supervised variational autoencoder based on the novel SELFIES representation to enable molecular design. We demonstrate the utility of the MOLAN workflow in the context of a challenging multi-molecule property prediction problem: the determination of melting points solely from single molecule structure. This application serves as a case study for how to employ the MOLAN workflow in the context of molecular property prediction.\",\n \"Title: DLIO: A Data-Centric Benchmark for Scientific Deep Learning Applications\\nYear: 2021\\n\\nAbstract: Deep learning has been shown as a successful method for various tasks, and its popularity results in numerous open-source deep learning software tools. Deep learning has been applied to a broad spectrum of scientific domains such as cosmology, particle physics, computer vision, fusion, and astrophysics. Scientists have performed a great deal of work to optimize the computational performance of deep learning frameworks. However, the same cannot be said for I/O performance. As deep learning algorithms rely on big-data volume and variety to effectively train neural networks accurately, I/O is a significant bottleneck on large-scale distributed deep learning training. This study aims to provide a detailed investigation of the I/O behavior of various scientific deep learning workloads running on the Theta supercomputer at Argonne Leadership Computing Facility. In this paper, we present DLIO, a novel representative benchmark suite built based on the I/O profiling of the selected workloads. DLIO can be utilized to accurately emulate the I/O behavior of modern scientific deep learning applications. Using DLIO, application developers and system software solution architects can identify potential I/O bottlenecks in their applications and guide optimizations to boost the I/O performance leading to lower training times by up to 6.7x.\",\n \"Title: Stream-AI-MD: Streaming AI-driven Adaptive Molecular Simulations for Heterogeneous Computing Platforms\\nYear: 2021\\n\\nAbstract: Emerging hardware tailored for artificial intelligence (AI) and machine learning (ML) methods provide novel means to couple them with traditional high performance computing (HPC) workflows involving molecular dynamics (MD) simulations. We propose StreamAI-MD, a novel instance of applying deep learning methods to drive adaptive MD simulation campaigns in a streaming manner. We leverage the ability to run ensemble MD simulations on GPU clusters, while the data from atomistic MD simulations are streamed continuously to AI/ML approaches to guide the conformational search in a biophysically meaningful manner on a wafer-scale AI accelerator. We demonstrate the efficacy of Stream-AI-MD simulations for two scientific use-cases: (1) folding a small prototypical protein, namely beta beta alpha-fold (BBA) FSD-EY and (2) understanding protein-protein interaction (PPI) within the SARS-CoV-2 proteome between two proteins, nsp16 and nsp10. We show that Stream-AI-MD simulations can improve time-to-solution by similar to 50X for BBA protein folding. Further, we also discuss performance trade-offs involved in implementing AI-coupled HPC workflows on heterogeneous computing architectures.\",\n \"Title: MLPerf™ HPC: A Holistic Benchmark Suite for Scientific Machine Learning on HPC Systems\\nYear: 2021\\n\\nAbstract: Scientific communities are increasingly adopting machine learning and deep learning models in their applications to accelerate scientific insights. High performance computing systems are pushing the frontiers of performance with a rich diversity of hardware resources and massive scale-out capabilities. There is a critical need to understand fair and effective benchmarking of machine learning appli...\",\n \"Title: AgEBO-tabular: joint neural architecture and hyperparameter search with autotuned data-parallel training for tabular data\\nYear: 2021\\n\\nAbstract: ABSTRACTDeveloping high-performing predictive models for large tabular data sets is a challenging task. Neural architecture search (NAS) is an AutoML approach that generates and evaluates multiple neural networks with different architectures concurrently to automatically discover an high performing model. A key issue in NAS, particularly for large data sets, is the large computation time required to evaluate each generated architecture. While data-parallel training has the potential to address this issue, a straightforward approach can result in significant loss of accuracy. To that end, we develop AgEBO-Tabular, which combines Aging Evolution (AE) to search over neural architectures and asynchronous Bayesian optimization (BO) to search over hyperparameters to adapt data-parallel training. We evaluate the efficacy of our approach on two large predictive modeling tabular data sets from the Exascale Computing Project-CANcer Distributed Learning Environment (ECP-CANDLE).\",\n \"Title: Efficient Design Space Exploration for Sparse Mixed Precision Neural Architectures\\nYear: 2022\\n\\nAbstract: BSTRACTPruning and Quantization are two effective Deep Neural Network (DNN) compression methods for efficient inference on various hardware platforms. Pruning refers to removing unimportant weights or nodes, whereas Quantization converts the floating-point parameters to low-bit fixed integer representation. The pruned and low precision models result in smaller and faster inference models on hardware platforms with almost the same accuracy as the unoptimized network. Tensor Cores in Nvidia Ampere 100 (A100) GPU supports (1) 2:4 fine-grained sparse pruning where 2 out of every 4 elements are pruned, and (2) traditional dense multiplication to achieve a good accuracy and performance trade-off. The A100 Tensor Core also takes advantage of 1-bit, 4-bit, and 8-bit multiplication to speed up the inference of a model. Hence, finding the right matrix type (dense or 2:4 sparse) along with the precision for each layer becomes a combinatorial problem. Neural Architecture Search (NAS) can alleviate such problems by automating the architecture design process instead of a brute-force search. In this paper, we propose (i) Mixed Sparse and Precision Search (MSPS), a NAS framework to search for efficient sparse and mixed-precision quantized model within the predefined search space and fixed backbone neural network (Eg. ResNet50), and (ii) Architecture, Sparse and Precision Search (ASPS) to jointly search for kernel size and number of filters, and sparse-precision combination of each layer. We illustrate the effectiveness of our methods targeting A100 Tensor Core on Nvidia GPUs by searching efficient sparse-mixed precision networks on ResNet50 and achieving better accuracy-latency trade-off models compared to the manually designed Uniform Sparse Int8 networks.\",\n \"Title: Stimulus: Accelerate Data Management for Scientific AI applications in HPC\\nYear: 2022\\n\\nAbstract: Modern scientific workflows couple simulations with AI-powered analytics by frequently exchanging data to accelerate time-to-science to reduce the complexity of the simulation planes. However, this data exchange is limited in performance and portability due to a lack of support for scientific data formats in AI frameworks. We need a cohesive mechanism to effectively integrate at scale complex scientific data formats such as HDF5, PnetCDF, ADIOS2, GNCF, and Silo into popular AI frameworks such as TensorFlow, PyTorch, and Caffe. To this end, we designed Stimulus, a data management library for ingesting scientific data effectively into the popular AI frameworks. We utilize the StimOps functions along with StimPack abstraction to enable the integration of scientific data formats with any AI framework. The evaluations show that Stimulus outperforms several large-scale applications with different use-cases such as Cosmic Tagger (consuming HDF5 dataset in PyTorch), Distributed FFN (consuming HDF5 dataset in TensorFlow), and CosmoFlow (converting HDF5 into TFRecord and then consuming that in TensorFlow) by 5.3 x, 2.9 x, and 1.9 x respectively with ideal I/O scalability up to 768 GPUs on the Summit supercomputer. Through Stimulus, we can portably extend existing popular AI frameworks to cohesively support any complex scientific data format and efficiently scale the applications on large-scale supercomputers.\",\n \"Title: Toward an In-Depth Analysis of Multifidelity High Performance Computing Systems\\nYear: 2022\\n\\nAbstract: To maintain a robust and reliable supercomputing facility, monitoring it and understanding its hardware system events and behaviors is an essential task. Exascale systems will be increasingly heterogeneous, and the volume of systems data, collected from multiple subsystems and components measured at multiple fidelity levels and temporal resolutions, will continue to grow. In this work, we aim to create an effective solution to analyze diverse and massive datasets gathered from the error logs, job logs, and environment logs of an HPC system, such as a Cray XC40 supercomputer. In this work, we build an end-to-end error log analysis system that analyzes the job logs and gleans insights from their correspondence with hardware error logs and environment logs despite their varying temporal and spatial resolutions. Our machine learning pipeline built in our system is ~92% accurate in predicting the job exit status and does so with sufficient lead time for evasive actions to be taken before the actual failure event occurs.\",\n \"Title: HDF5 Cache VOL: Efficient and Scalable Parallel I/O through Caching Data on Node-local Storage\\nYear: 2022\\n\\nAbstract: Modern-era high performance computing (HPC) systems are providing multiple levels of memory and storage layers to bridge the performance gap between fast memory and slow disk-based storage system managed by Lustre or GPFS. Several of the recent HPC systems are equipped with SSD and NVMe-based storage that is attached locally to compute nodes. A few systems are providing an SSD-based “burst buffer” intermediate storage layer that is accessible by all compute nodes as a single file system. Although these hardware layers are intended to reduce the latency gap between memory and disk-based long-term storage, how to utilize them has been left to the users. High-level I/O libraries, such as HDF5 and netCDF, can potentially take advantage of the node-local storage as a cache for reducing I/O latency from capacity storage. However, it is challenging to use node-local storage in parallel I/O especially for a single shared file. In this paper, we present an approach to integrate node-local storage as transparent caching or staging layers in a high-level parallel I/O library without placing the burden of managing these layers on users. We designed this to move data asynchronously between the caching storage layer and a parallel file system to overlap the data movement overhead in performing I/O with compute phases. We implement this approach as an external HDF5 Virtual Object Layer (VOL) connector, named Cache VOL. HDF5 VOL is a layer of abstraction in HDF5 that allows intercepting the public HDF5 application programming interface (API) and performing various optimizations to data movement after the interception. Existing HDF5 applications can use Cache VOL with minimal code modifications. We evaluated the performance of Cache VOL in HPC applications such as VPIC-10, and deep learning applications such as ImageNet and CosmoFlow. We show that using Cache VOL, one can achieve higher observed I/O performance, more scalable and stable I/O compared to direct I/O to the parallel file system, thus achieving faster time-to-solution in scientific simulations. While the caching approach is implemented in HDF5, the methods are applicable in other high-level I/O libraries.\",\n \"Title: Neural Architecture Search for Transformers: A Survey\\nYear: 2022\\n\\nAbstract: Transformer-based Deep Neural Network architectures have gained tremendous interest due to their effectiveness in various applications across Natural Language Processing (NLP) and Computer Vision (CV) domains. These models are the de facto choice in several language tasks, such as Sentiment Analysis and Text Summarization, replacing Long Short Term Memory (LSTM) model. Vision Transformers (ViTs) have shown better model performance than traditional Convolutional Neural Networks (CNNs) in vision applications while requiring significantly fewer parameters and training time. The design pipeline of a neural architecture for a given task and dataset is extremely challenging as it requires expertise in several interdisciplinary areas such as signal processing, image processing, optimization and allied fields. Neural Architecture Search (NAS) is a promising technique to automate the architectural design process of a Neural Network in a data-driven way using Machine Learning (ML) methods. The search method explores several architectures without requiring significant human effort, and the searched models outperform the manually built networks. In this paper, we review Neural Architecture Search techniques, targeting the Transformer model and its family of architectures such as Bidirectional Encoder Representations from Transformers (BERT) and Vision Transformers. We provide an in-depth literature review of approximately 50 state-of-the-art Neural Architecture Search methods and explore future directions in this fast-evolving class of problems.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":86,"string":"86"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13368,"string":"13,368"}}},{"rowIdx":13369,"cells":{"question_id":{"kind":"string","value":"Ivan Bratko"},"question":{"kind":"string","value":"Generate an abstract for the title \"Argument based machine learning applied to law\" using the following items: 1. AGATHA\n2. theory construction \n3. case-based domains \n4. automation \n5. argument moves"},"answer":{"kind":"string","value":"In this paper we describe AGATHA, a program designed to automate the process of theory construction in case based domains. Given a seed case and a number of precedent cases, the program uses a set of argument moves to generate a search space for a dialogue ..."},"correct_answer":{"kind":"string","value":"In this paper we describe AGATHA, a program designed to automate the process of theory construction in case based domains. Given a seed case and a number of precedent cases, the program uses a set of argument moves to generate a search space for a dialogue ..."},"documents":{"kind":"list like","value":["Title: LRTA\nYear: 2008\n\nAbstract: Recently we showed that under very reasonable conditions, incomplete, real-time search methods like RTA* work better with pessimistic heuristic functions than with optimistic, admissible heuristic functions of equal quality. The use of pessimistic heuristic function,; results in higher percentage of correct decisions and in shorter solution lengths. We extend this result to learning RTA* (LRTA*) and demonstrate that the use of pessimistic instead of optimistic (or mixed) heuristic functions of equal quality results in much faster learning process at the cost of just marginally worse quality of converged solutions.","Title: Analyzing Attribute Dependencies\nYear: 2003\n\nAbstract: Many effective and efficient learning algorithms assume independence of attributes. They often perform well even in domains where this assumption is not really true. However, they may fail badly when the degree of attribute dependencies becomes critical. In this paper, we examine methods for detecting deviations from independence. These dependencies give rise to \"interactions\" between attributes which affect the performance of learning algorithms. We first formally define the degree of interaction between attributes through the deviation of the best possible \"voting\" classifier from the true relation between the class and the attributes in a domain. Then we propose a practical heuristic for detecting attribute interactions, called interaction gain. We experimentally investigate the suitability of interaction gain for handling attribute interactions in machine learning. We also propose visualization methods for graphical exploration of interactions in a domain.","Title: Automated Chess Tutor\nYear: 2006\n\nAbstract: While recently the strength of chess playing programs has grown immensely, their capability of explaining in human understand- able terms why some moves are good or bad has enjoyed little attention. Progress towards programs' ability to intelligently comment chess games, played either by the program or human, has been negligible in compari- son with their playing strength. Typical style of program's \\comments\" in terms of the best variations and their numerical scores is of little use to a human who wants to learn important concepts behind these vari- ations. In this paper, we present some core mechanisms for automated commenting in terms of relevant goals to be achieved or preserved in a given position. By combining these mechanisms with an actual chess en- gine we were able to transform this engine into a chess tutor/annotator that is capable of generating rather intelligent commentary. The main advantage of our work over related approaches is: (a) ability to tutor the whole game of chess, and (b) relatively solid understanding and com- menting of positional aspects of positions.","Title: First Order Regression\nYear: 1997\n\nAbstract: We present a new approach, called First Order Regression (FOR),to handling numerical information in Inductive Logic Programming (ILP).FOR is a combination of ILP and numerical regression.First-order logic descriptions are induced to carve out those subspacesthat are amenable to numerical regression among real-valued variables.The program FORS is an implementation of this idea, where numericalregression is focused on a distinguished continuous argument of the targetpredicate. We show that this can be viewed as a generalisation of theusual ILP problem. Applications of FORS on several real-world datasets are described: the prediction of mutagenicity of chemicals, themodelling of liquid dynamics in a surge tank, predicting theroughness in steel grinding, finite element mesh design, andoperator‘s skill reconstruction in electric discharge machining. Acomparison of FORS‘ performance with previous results in thesedomains indicates that FORS is an effective tool for ILP applicationsthat involve numerical data.","Title: Learning qualitative models\nYear: 2004\n\nAbstract: In general, modeling is a complex and creative task, and building qualitative models is no exception. One way of automating this task is by means of machine learning. Observed behaviors of a modeled system are used as examples for a learning algorithm that constructs a model that is consistent with the data. In this article, we review approaches to learning qualitative models, either from numeric data or qualitative observations. We describe the QUIN program that looks for qualitative patterns in numeric data and outputs the results of learning as \"qualitative trees.\" We illustrate this using applications associated with systems control, in particular, the identification and optimization of controllers and human operator's control skill. We also review approaches that learn models in terms of qualitative differential equations.","Title: Goal-Oriented conceptualization of procedural knowledge\nYear: 2012\n\nAbstract: Conceptualizing procedural knowledge is one of the most challenging tasks of building systems for intelligent tutoring. We present an algorithm that enables teachers to accomplish this task semi automatically. We used the algorithm on a difficult king, bishop, and knight versus the lone king (KBNK) chess endgame, and obtained concepts that could serve as textbook instructions. A pilot experiment with students and a separate evaluation of the instructions by experienced chess trainers were deemed very positive.","Title: Nomograms for visualizing support vector machines\nYear: 2005\n\nAbstract: We propose a simple yet potentially very effective way of visualizing trained support vector machines. Nomograms are an established model visualization technique that can graphically encode the complete model on a single page. The dimensionality of the visualization does not depend on the number of attributes, but merely on the properties of the kernel. To represent the effect of each predictive feature on the log odds ratio scale as required for the nomograms, we employ logistic regression to convert the distance from the separating hyperplane into a probability. Case studies on selected data sets show that for a technique thought to be a black-box, nomograms can clearly expose its internal structure. By providing an easy-to-interpret visualization the analysts can gain insight and study the effects of predictive factors.","Title: Inductive Learning Applied to Program Construction and Verification\nYear: 1992\n\nAbstract: In this paper we show how techniques of Inductive Logic Programming (ILP), a form of inductive learning, can be applied to some traditional problems of program development and verification. First we consider the problem of data reification when refining an abstract program specification into a more concrete one, that is one closer to the target implementation language. An ILP system is then used to automatically construct a target language program specification. Second, we apply the ILP approach to automatic construction of loop invariants in formal proofs of program correctness.","Title: Learning qualitative models from numerical data\nYear: 2011\n\nAbstract: Qualitative models describe relations between the observed quantities in qualitative terms. In predictive modelling, a qualitative model tells whether the output increases or decreases with the input. We describe Pade, a new method for qualitative learning which estimates partial derivatives of the target function from training data and uses them to induce qualitative models of the target function. We formulated three methods for computation of derivatives, all based on using linear regression on local neighbourhoods. The methods were empirically tested on artificial and real-world data. We also provide a case study which shows how the developed methods can be used in practice.","Title: Learning qualitative models of dynamic systems\nYear: 1991\n\nAbstract: A technique is described for learning qualitative models of dynamicsystems. The QSIM formalism is used as a representation forlearned qualitative models. The problem of learning QSIM-type modelsis formulated in logic, and the GOLEM learning program is usedfor induction. An experiment in learning a qualitative model of theconnected containers system, also called U-tube, is described in detail.1 IntroductionIt has been shown that qualitative models are better suited for several tasksthan ...","Title: Engineering Applications of ILP.\nYear: 1995\n\nAbstract: Several applications of Inductive Logic Programming (ILP) are presented. These belong to various areas of engineering, including\n mechanical, environmental, software, and dynamical systems engineering. The particular applications are finite element mesh\n design, biological classification of river water quality, data reification, inducing program invariants, learning qualitative\n models of dynamic systems, and learning control rules for dynamic systems. A number of other applications are briefly mentioned.\n Finally, a discussion of the advantages and disadvantages of ILP as compared to other approaches to machine learning is given.","Title: Argument-based machine learning\nYear: 2007\n\nAbstract: In this paper, some recent ideas will be presented about making machine learning (ML) more effective through mechanisms of argumentation. In this sense, argument-based machine learning (ABML) is defined as a refinement of the usual definition of ML. In ABML, some learning examples are accompanied by arguments, that are expert's reasons for believing why these examples are as they are. Thus ABML provides a natural way of introducing domain-specific prior knowledge in a way that is different from the traditional, general background knowledge. The task of ABML is to find a theory that explains the \"argumented\" examples by making reference to the given reasons. ABML, so defined, is motivated by the following advantages in comparison with standard learning from examples: (1) arguments impose constraints over the space of possible hypotheses, thus reducing search complexity, and (2) induced theories should make more sense to the expert. Ways of realising ABML by extending some existing ML techniques are discussed, and the aforementioned advantages of ABML are demonstrated experimentally.","Title: Argument Based Rule Learning\nYear: 2006\n\nAbstract: We present a novel approach to machine learning, called ABML (argumentation based ML). This approach combines machine learning from examples with concepts from the field of argumentation. The idea is to provide expert's arguments, or reasons, for some of the learning examples. We require that the theory induced from the examples explains the examples in terms of the given reasons. Thus arguments constrain the combinatorial search among possible hypotheses, and also direct the search towards hypotheses that are more comprehensible in the light of expert's background knowledge. In this paper we implement ABCN2 as an extension of the CN2 rule learning algorithm, and analyze its advantages in comparison with the original CN2 algorithm.","Title: Implementing search heuristics using the AL1 advice-taking system\nYear: 1979\n\nAbstract: The AL1 System (Advice Language 1) was developed as a vehicle for conveying expert knowledge, or advice, to a problem solver. Using chess end-games as an experimental problem domain, this paper concentrates on the question: How to implement chess heuristics using the mechanisms of AL1? The spirit of advice programming as a sort of \"tree-search engineering\" is illustrated by developing an AL1 piece-of-advice for solving an example problem from the king-knight vs. king-rook chess ending. Experiments indicate that an advice program for this ending, based on comparatively simple concepts, and the human chess master perform comparably.","Title: Induction of Qualitative Trees\nYear: 2001\n\nAbstract: We consider the problem of automatic construction of qualitative models by inductive learning from quantitative examples. We present an algorithm QUIN (QUalitative INduction) that learns qualitative trees from a set of examples described with numerical attributes. At difference with decision trees, the leaves of qualitative trees contain qualitative functional constraints as used in qualitative reasoning. A qualitative tree defines a partition of the attribute space into the areas with common qualitative behaviour of the chosen class variable. We describe a basic algorithm for induction of qualitative trees, improve it to the heuristic QUIN algorithm, and give experimental evaluation of the algorithms on a set of artificial domains. QUIN has already been used to induce qualitative control strategies in dynamic domains such as controlling a crane or riding a bicycle (described elsewhere) and can be applied to other domains as a general tool for qualitative system identification.","Title: Simple and effective visual models for gene expression cancer diagnostics\nYear: 2005\n\nAbstract: In the paper we show that diagnostic classes in cancer gene expression data sets, which most often include thousands of features (genes), may be effectively separated with simple two-dimensional plots such as scatterplot and radviz graph. The principal innovation proposed in the paper is a method called VizRank, which is able to score and identify the best among possibly millions of candidate projections for visualizations. Compared to recently much applied techniques in the field of cancer genomics that include neural networks, support vector machines and various ensemble-based approaches, VizRank is fast and finds visualization models that can be easily examined and interpreted by domain experts. Our experiments on a number of gene expression data sets show that VizRank was always able to find data visualizations with a small number of (two to seven) genes and excellent class separation. In addition to providing grounds for gene expression cancer diagnosis, VizRank and its visualizations also identify small sets of relevant genes, uncover interesting gene interactions and point to outliers and potential misclassifications in cancer data sets.","Title: Learning Predictive Qualitative Models With Pade\nYear: 2011\n\nAbstract: Qualitative models are similar to regression models, except that instead of numerical predictions they provide insight into how a change of a certain input variable affects the output within a context of other inputs. Although people usually reason qualitatively, machine learning has mostly ignored this type of model. We present a new approach to learning qualitative models from numerical data. We describe Pade, a suite of methods for estimating partial derivatives of unknown sampled target functions. We show how to build qualitative models using standard machine learning algorithms by replacing the output variable with signs of computed derivatives.Experiments show that the developed methods are quite accurate, scalable to high number of dimensions and robust with regard to noise.","Title: Qualitatively faithful quantitative prediction\nYear: 2003\n\nAbstract: Abstract We describe an approach to machine,learning from numerical data that combines,both qualitative and numerical learning. This approach is carried out in two stages: (1) induction of a qualitative model from numerical examples of the behaviour of a physical system, and (2) induction of a numerical,regression function that both respects the qualitative constraints and fits the training data numerically. We call this approach Q, learning to the identification of a car wheel suspension system—a complex, industrially relevant mechanical system. 2004 Elsevier B.V. All rights reserved. Keywords: Automated model building; System identification; Machine learning; Qualitative reasoning; Learning","Title: Pessimistic Heuristics Beat Optimistic Ones in Real-Time Search\nYear: 2006\n\nAbstract: Admissibility is a desired property of heuristic evaluation functions, because when these heuristics are used with complete search methods, such as A* and RBFS, they guarantee that an optimal solution will be found. Since every optimistic heuristic function is admissible, optimistic functions are widely used. We show, however, that with incomplete, real-time search, optimistic functions lose their appeal, and in fact they may hinder the search under quite reasonable conditions. Under these conditions the exact opposite is to be preferred, i.e. pessimistic heuristic functions that never underestimate the difficulty of the problem. We demonstrate that such heuristics behave better than optimistic ones of equal quality on a standard testbed using RTA* search method.","Title: Autonomous discovery of abstract concepts by a robot\nYear: 2011\n\nAbstract: In this paper we look at the discovery of abstract concepts by a robot autonomously exploring its environment and learning the laws of the environment. By abstract concepts we mean concepts that are not explicitly observable in the measured data, such as the notions of obstacle, stability or a tool. We consider mechanisms of machine learning that enable the discovery of abstract concepts. Such mechanisms are provided by the logic based approach to machine learning called Inductive Logic Programming (ILP). The feature of predicate invention in ILP is particularly relevant. Examples of actually discovered abstract concepts in experiments are described.","Title: Discovery of Genetic Networks Through Abduction and Qualitative Simulation\nYear: 2007\n\nAbstract: GenePath is an automated system for reasoning about genetic networks, wherein a set of genes have various influences on one another and on a biological outcome. It acts on a set of experiments in which genes are knocked-out or overexpressed, and the outcome of interest is evaluated. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on background knowledge and experimental results. Two uses of the system are demonstrated: synthesis of a consistent network from abduced constraints, and qualitative reasoning-based approach that generates a set of networks consistent with the data. In practice, as illustrated by an example on aggregation of a soil amoeba Dictyostelium discoideum, a combination of constraint satisfaction and qualitative reasoning produces a small set of plausible networks.","Title: Learning to Fly Simple and Robust\nYear: 2004\n\nAbstract: We report on new experiments with machine learning in the reconstruction of human sub-cognitive skill. The particular problem considered is to generate a clone of a human pilot performing a flying task on a simulated aircraft. The work presented here uses the human behaviour to create constraints for a search process that results in a controller - pilot's clone. Experiments in this paper indicate that this approach, called \"indirect controllers\", results in pilot clones that are, in comparison with those obtained with traditional \"direct controllers\", simpler, more robust and easier to understand. An important feature of indirect controllers in this paper is the use of qualitative constraints.","Title: Factors Affecting Diminishing Returns For Searching Deeper\nYear: 2007\n\nAbstract: The phenomenon of diminishing returns for additional search effort has been observed by several researchers. We study experimentally additional factors which influence the behaviour of diminishing returns that manifest themselves in go-deep experiments. The results obtained on a large set of more than 40,000 positions from chess grandmaster games using the programs CRAFTY, RYBKA, and SHREDDER show that diminishing returns depend on (a) the values of the positions, (b) the quality of the evaluation function of the program used, and to some extent also on (c) the phase of the game, and the amount of material on the board.","Title: Fighting Knowledge Acquisition Bottleneck with Argument Based Machine Learning\nYear: 2008\n\nAbstract: Knowledge elicitation is known to be a difficult task and thus a major bottleneck in building a knowledge base. Machine learning has long ago been proposed as a way to alleviate this problem. Machine learning usually helps the domain expert to uncover some of the more tacit concepts. However, the learned concepts are often hard to understand and hard to extend. A common view is that a combination of a domain expert and machine learning would yield the best results. Recently, argument based machine learning (ABML) has been introduced as a combination of argumentation and machine learning. Through argumentation, ABML enables the expert to articulate his knowledge easily and in a very natural way. ABML was shown to significantly improve the comprehensibility and accuracy of the learned concepts. This makes ABML a most natural tool for constructing a knowledge base. The present paper shows how this is accomplished through a case study of building a knowledge base of an expert system used in a chess tutoring application.","Title: Attribute Interactions in Medical Data Analysis\nYear: 2003\n\nAbstract: There is much empirical evidence about the success of naive Bayesian classification (NBC) in medical applications of attribute-based machine learning. NBC assumes conditional independence between attributes. In classification, such classifiers sum up the pieces of class-related evidence from individual attributes, independently of other attributes. The performance, however, deteriorates significantly when the \"interactions\" between attributes become critical. We propose an approach to handling attribute interactions within the framework of \"voting\" classifiers, such as NBC. We propose an operational test for detecting interactions in learning data and a procedure that takes the detected interactions into account while learning. This approach induces a structuring of the domain of attributes, it may lead to improved classifier's performance and may provide useful novel information for the domain expert when interpreting the results of learning. We report on its application in data analysis and model construction for the prediction of clinical outcome in hip arthroplasty.","Title: Combining learning constraints and numerical regression\nYear: 2005\n\nAbstract: Usual numerical learning methods are primarily concerned with finding a good numerical fit to data and often make predictions that do not correspond to qualitative laws in the domain of modelling or expert intuition. In contrast, the idea of Q2 learning is to induce qualitative constraints from training data, and use the constraints to guide numerical regression. The resulting numerical predictions are consistent with a learned qualitative model which is beneficial in terms of explanation of phenomena in the modelled domain, and can also improve numerical accuracy. This paper proposes a method for combining the learning of qualitative constraints with an arbitrary numerical learner and explores the accuracy and explanation benefits of learning monotonic qualitative constraints in a number of domains. We show that Q2 learning can correct for errors caused by the bias of the learning algorithm and discuss the potentials of similar hierarchical learning schemes.","Title: Embodied Concept Discovery Through Qualitative Action Models\nYear: 2011\n\nAbstract: We present a novel approach to embodied learning of qualitative models. We introduce, algorithm STRUDEL that enables an autonomous robot to discover new concepts by performing experiments in its environment. The robot collects data about its actions and its observations of the environment. Prom the obtained data, the robot lean is qualitative descriptive models of the effects that its actions have in the environment. Models are learned using inductive logic programming. We describe two experiments with a humanoid robot Nao in which Nao learns descriptive qualitative models which contain what can be interpreted as simple definitions of the concepts of movability and stability.","Title: Information-Based Evaluation Criterion for Classifier's Performance\nYear: 1991\n\nAbstract: In the past few years many systems for learning decision rules from examples were developed. As different systems allow different types of answers when classifying new instances, it is difficult to appropriately evaluate the systems' classification power in comparison with other classification systems or in comparison with human experts. Classification accuracy is usually used as a measure of classification performance. This measure is, however, known to have several defects. A fair evaluation criterion should exclude the influence of the class probabilities which may enable a completely uninformed classifier to trivially achieve high classification accuracy. In this paper a method for evaluating the information score of a classifier's answers is proposed. It excludes the influence of prior probabilities, deals with various types of imperfect or probabilistic answers and can be used also for comparing the performance in different domains.","Title: Constructing Intermediate Concepts by Decomposition of Real Functions\nYear: 1997\n\nAbstract: . In learning from examples it is often useful to expand an attribute-vectorrepresentation by intermediate concepts. The usual advantage of such structuring of thelearning problem is that it makes the learning easier and improves the comprehensibilityof induced descriptions. In this paper, we develop a technique for discovering usefulintermediate concepts when both the class and the attributes are real-valued. Thetechnique is based on a decomposition method originally developed for the...","Title: Trading Accuracy for Simplicity in Decision Trees\nYear: 1994\n\nAbstract: When communicating concepts, it is often convenient or even necessary to define a concept approximately. A simple, although only approximately accurate concept definition may be more useful than a completely accurate definition which involves a lot of detail. This paper addresses the problem: given a completely accurate, but complex, definition of a concept, simplify the definition, possibly at the expense of accuracy, so that the simplified definition still corresponds to the concept “sufficiently” well. Concepts are represented by decision trees, and the method of simplification is tree pruning. Given a decision tree that accurately specifies a concept, the problem is to find a smallest pruned tree that still represents the concept within some specified accuracy. A pruning algorithm is presented that finds an optimal solution by generating a dense sequence of pruned trees, decreasing in size, such that each tree has the highest accuracy among all the possible pruned trees of the same size. An efficient implementation of the algorithm, based on dynamic programming, is presented and empirically compared with three progressive pruning algorithms using both artificial and real-world data. An interesting empirical finding is that the real-world data generally allow significantly greater simplification at equal loss of accuracy.","Title: Multi-agent strategic modeling in a robotic soccer domain\nYear: 2006\n\nAbstract: This paper presents an algorithm for multi-agent strategic modeling (MASM) applied in a robotic soccer domain. It transforms a multi-agent action sequence into a set of strategic action descriptions in a graphical and symbolic form. By using hierarchically ordered domain knowledge, the algorithm is able to generate graphic and symbolic strategic action descriptions together with corresponding rules at different levels of abstraction. The method was evaluated on the RoboCup Soccer Server Internet League data.","Title: Elicitation of neurological knowledge with ABML\nYear: 2011\n\nAbstract: The paper describes the process of knowledge elicitation for a neurological decision support system. To alleviate the difficult problem of knowledge elicitation from data and domain experts, we used a recently developed technique called ABML (Argument Based Machine Learning). The paper demonstrates ABML's advantage in combining machine learning and expert knowledge. ABML guides the expert to explain critical special cases which cannot be handled automatically by machine learning. This very efficiently reduces the expert's workload, and combines it with automatically learned knowledge. We developed a decision support system to help the neurologists differentiate between three types of tremors: Parkinsonian, essential, and mixed tremor (co-morbidity). The system is intended to act as a second opinion for the neurologists, and most importantly to help them reduce the number of patients in the \"gray area\" that require a very costly further examination (DaTSCAN).","Title: Microarray data mining with visual programming.\nYear: 2005\n\nAbstract: Visual programming offers an intuitive means of combining known analysis and visualization methods into powerful applications. The system presented here enables users who are not programmers to manage microarray and genomic data flow and to customize their analyses by combining common data analysis tools to fit their needs.http://www.ailab.si/supp/bi-visproghttp://www.ailab.si/supp/bi-visprog.","Title: Knowledge base for finite-element mesh design learned by inductive logic programming\nYear: 1998\n\nAbstract: This paper addresses an important application of machine learning (ML) in design. One of the major bottlenecks in the process of engineering analysis by using the finite-element method—a design of the finite-element mesh—was a subject of improvement. Defining an appropriate geometric mesh model that ensures low approximation errors and avoids unnecessary computational overhead is a very difficult and time-consuming task based mainly on the user's experience. A knowledge base for finite-element mesh design has been constructed using the ML techniques. Ten mesh models have been used as a source of training examples. The mesh dataset was probably the first real-world relational dataset and became one of the most widely used training set for experimenting with inductive logic programming (ILP) systems. After several experiments with different ML systems in the last few years, the ILP system CLAUDIEN was chosen to construct the rules for determining the appropriate mesh resolution values. The ILP has been found to be an effective approach to the problem of mesh design. An evaluation of the resulting knowledge base shows that the mesh design patterns are captured well by the induced rules and represent a solid basis for practical application. The aim of this paper is not only to present the real-life ML application to design, but also to describe and discuss a relation of the work being done to the topic of this special issue: the proposed “dimensions” of ML in design.","Title: Symbolic and qualitative reconstruction of control skill\nYear: 1999\n\nAbstract: Controlling a complex dynamic system, such as a plane or acrane, usually requires a skilled operator. Such a control skillis typically hard to reconstruct through introspection. Thereforean attractive approach to the reconstruction of control skillinvolves machine learning from operators\" control traces, alsoknown as behavioural cloning. In the most common approach tobehavioural cloning, a controller is induced as a direct mappingfrom system states to actions. Unfortunately, such...","Title: ABML knowledge refinement loop: a case study\nYear: 2012\n\nAbstract: Argument Based Machine Learning (ABML) was recently demonstrated to offer significant benefits for knowledge elicitation. In knowledge acquisition, ABML is used by a domain expert in the so-called ABML knowledge refinement loop. This draws the expert's attention to the most critical parts of the current knowledge base, and helps the expert to argue about critical concrete cases in terms of the expert's own understanding of such cases. Knowledge elicited through ABML refinement loop is therefore more consistent with expert's knowledge and thus leads to more comprehensible models in comparison with other ways of knowledge acquisition with machine learning from examples. Whereas the ABML learning method has been described elsewhere, in this paper we concentrate on detailed mechanisms of the ABML knowledge refinement loop. We illustrate these mechanisms with examples from a case study in the acquisition of neurological knowledge, and provide quantitative results that demonstrate how the model evolving through the ABML loop becomes increasingly more consistent with the expert's knowledge during the process.","Title: Deriving concepts and strategies from chess tablebases\nYear: 2009\n\nAbstract: Complete tablebases, indicating best moves for every position, exist for chess endgames. There is no doubt that tablebases contain a wealth of knowledge, however, mining for this knowledge, manually or automatically, proved as extremely difficult. Recently, we developed an approach that combines specialized minimax search with the argument-based machine learning (ABML) paradigm. In this paper, we put this approach to test in an attempt to elicit human-understandable knowledge from tablebases. Specifically, we semi-automatically synthesize knowledge from the KBNK tablebase for teaching the difficult king, bishop, and knight versus the lone king endgame.","Title: Machine learning applied to quality management-A study in ship repair domain\nYear: 2007\n\nAbstract: The awareness about the importance of knowledge within the quality management community is increasing. For example, the Malcolm Baldrige Criteria for Performance Excellence recently included knowledge management into one of its categories. However, the emphasis in research related to knowledge management is mostly on knowledge creation and dissemination, and not knowledge formalisation process. On the other hand, identifying the expert knowledge and experience as crucial for the output quality, especially in dynamic industries with high share of incomplete and unreliable information such as ship repair, this paper argues how important it is to have such knowledge formalised. The paper demonstrates by example of delivery time estimate how for that purpose the deep quality concept (DQC)-a novel knowledge-focused quality management framework, and machine learning methodology could be effectively used. In the concluding part of the paper, the accuracy of the obtained prediction models is analysed, and the chosen model is discussed. The research indicates that standardisation of problem domain notions and expertly designed databases with possible interface to machine learning algorithms need to be considered as an integral part of any quality management system in the future, in addition to conventional quality management concepts.","Title: Function decomposition in machine learning\nYear: 2001\n\nAbstract: To solve a complex problem, one of the effective general approaches is to decompose it into smaller, less complex and more\n manageable subproblems. In machine learning, this principle is a foundation for structured induction [44]: instead of learning\n a single complex classification rule from examples, define a concept hierarchy and learn rules for each of the (sub)concepts.\n Shapiro [44] used structured induction for the classification of a fairly complex chess endgame and demonstrated that the\n complexity and comprehensiveness (“brain-compatibility”) of the obtained solution was superior to the unstructured one. Shapiro\n was helped by a chess master to structure his problem domain. Typically, applications of structured induction involve a manual\n development of the hierarchy and a manual selection and classification of examples to induce the subconcept classification\n rules; usually this is a tiresome process that requires an active availability of a domain expert over long periods of time.\n Therefore, it would be very desirable to automate the problem decomposition task.","Title: Machine learning for survival analysis: a case study on recurrence of prostate cancer\nYear: 2000\n\nAbstract: Machine learning techniques have recently received considerable attention, especially when used for the construction of prediction models from data. Despite their potential advantages over standard statistical methods, like their ability to model non-linear relationships and construct symbolic and interpretable models, their applications to survival analysis are at best rare, primarily because of the difficulty to appropriately handle censored data. In this paper we propose a schema that enables the use of classification methods — including machine learning classifiers — for survival analysis. To appropriately consider the follow-up time and censoring, we propose a technique that, for the patients for which the event did not occur and have short follow-up times, estimates their probability of event and assigns them a distribution of outcome accordingly. Since most machine learning techniques do not deal with outcome distributions, the schema is implemented using weighted examples. To show the utility of the proposed technique, we investigate a particular problem of building prognostic models for prostate cancer recurrence, where the sole prediction of the probability of event (and not its probability dependency on time) is of interest. A case study on preoperative and postoperative prostate cancer recurrence prediction shows that by incorporating this weighting technique the machine learning tools stand beside modern statistical methods and may, by inducing symbolic recurrence models, provide further insight to relationships within the modeled data.","Title: Is real-valued minimax pathological?\nYear: 2006\n\nAbstract: Deeper searches in game-playing programs relying on the minimax principle generally produce better results. Theoretical analyses, however, suggest that in many cases minimaxing amplifies the noise introduced by the heuristic function used to evaluate the leaves of the game tree, leading to what is known as pathological behavior, where deeper searches produce worse results. In most minimax models analyzed in previous research, positions' true values and sometimes also heuristic values were only losses and wins. In contrast to this, a model is proposed in this paper that uses real numbers for both true and heuristic values. This model did not behave pathologically in the experiments performed. The mechanism that causes deeper searches to produce better evaluations is explained. A comparison with chess is made, indicating that the model realistically reflects position evaluations in chess-playing programs. Conditions under which the pathology might appear in a real-value model are also examined. The essential difference between our real-value model and the common two-value model, which causes the pathology in the two-value model, is identified. Most previous research reports that the pathology tends to disappear when there are dependences between the values of sibling nodes in a game tree. In this paper, another explanation is presented which indicates that in the two-value models the error of the heuristic evaluation was not modeled realistically.","Title: Computer Analysis Of World Chess Champions\nYear: 2006\n\nAbstract: Who is the best chess player of all time? Chess players are often interested in this question that has never been answered authoritatively, because it requires a comparison between chess players of different eras who never met across the board. In this contribution, we attempt to make such a comparison. It is based on the evaluation of the games played by the World Chess Champions in their championship matches. The evaluation is performed by the chess-playing program CRAFTY. For this purpose we slightly adapted CRAFTY. Our analysis takes into account the differences in players' styles to compensate the fact that calm positional players in their typical games have less chance to commit gross tactical errors than aggressive tactical players. Therefore, we designed a method to assess the difficulty of positions. Some of the results of this computer analysis might be quite surprising. Overall, the results can be nicely interpreted by a chess expert.","Title: Proving correctness of strategies in the AL1 assertional language\nYear: 1978\n\nAbstract: Combinatorial programming, program correctness, computer chess","Title: Application of argument based machine learning to law\nYear: 2005\n\nAbstract: In this paper we discuss the application of a new machine learning approach - argumentation based machine learning - to the legal domain. Argumentation based machine learning is particularly suited to law as it makes use of the justifications of decisions to guide its learning. Importantly, where a large number of decided cases are available, it provides a way of identifying which need to be considered, so that only decisions which will have an influence are examined.","Title: Testing the significance of attribute interactions\nYear: 2004\n\nAbstract: Attribute interactions are the irreducible dependencies between attributes. Interactions underlie feature relevance and selection, the structure of joint probability and classification models: if and only if the attributes interact, they should be connected. While the issue of 2-way interactions, especially of those between an attribute and the label, has already been addressed, we introduce an operational definition of a generalized n-way interaction by highlighting two models: the reductionistic part-to-whole approximation, where the model of the whole is reconstructed from models of the parts, and the holistic reference model, where the whole is modelled directly. An interaction is deemed significant if these two models are significantly different. In this paper, we propose the Kirkwood superposition approximation for constructing part-to-whole approximations. To model data, we do not assume a particular structure of interactions, but instead construct the model by testing for the presence of interactions. The resulting map of significant interactions is a graphical model learned from the data. We confirm that the P-values computed with the assumption of the asymptotic X2 distribution closely match those obtained with the boot-strap.","Title: A Program For Playing Tarok\nYear: 2003\n\nAbstract: A program for playing the three-player tarok card game is presented and the complexity of the game is analyzed. To deal with the unknown distributions of other players' cards, the program uses a sampling method that accomplishes hierarchical clustering to select representative sets of cards from a host of, randomly generated sets. A, game tree is searched with the alpha-beta algorithm using several common enhancements and an equivalence transposition table, which group the positions by strategic similarity instead of storing single positions.","Title: Applications of inductive logic programming\nYear: 1994\n\nAbstract: Techniques of machine learning have been successfully applied to various problems [1, 12]. Most of these applications rely on attribute-based learning, exemplified by the induction of decision trees as in the program C4.5 [20]. Broadly speaking, attribute-based learning also includes such approaches to learning as neural networks and nearest neighbor techniques. The advantages of attribute-based learning are: relative simplicity, efficiency, and existence of effective techniques for handling noisy data. However, attribute-based learning is limited to non-relational descriptions of objects in the sense that the learned descriptions do not specify relations among the objects' parts. Attribute-based learning thus has two strong limitations:the background knowledge can be expressed in rather limited form, andthe lack of relations makes the concept description language inappropriate for some domains.","Title: Abductive Inference of Genetic Networks\nYear: 2001\n\nAbstract: GenePath is an automated system for reasoning on genetic networks, wherein a set of genes have various influences on one another and on a biological outcome. It acts on a set of experiments in which genes are knocked out or overexpressed, and the outcome of interest is evaluated. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on prior knowledge and experimental results. Two uses of the system are demonstrated: synthesis of a consistent network from abduced constraints, and qualitative reasoning-based approach that generates a set of networks consistent with the data. In practice, illustrated by an example using Dictyostelium aggregation, a combination of constraint satisfaction and qualitative reasoning produces a small set of plausible networks.","Title: Argument Based Machine Learning from Examples and Text\nYear: 2009\n\nAbstract: We introduce a novel approach to cross-media learning based on argument based machine learning (ABML). ABML is a recent method that combines argumentation and machine learning from examples, and its main idea is to use arguments for some of the learning examples. Arguments are usually provided by a domain expert. In this paper, we present an alternative approach, where arguments used in ABML are automatically extracted from text with a technique for relation extraction. We demonstrate and evaluate the approach through a case study of learning to classify animals by using arguments automatically extracted from Wikipedia.","Title: Argument based machine learning in a medical domain\nYear: 2006\n\nAbstract: Argument Based Machine Learning (ABML) is a new approach to machine learning in which the learning examples can be accompanied by arguments. The arguments for specific examples are a special form of expert's knowledge which the expert uses to substantiate the class value for the chosen example. Možina et al. developed the ABCN2 algorithm-an extension of the well known rule learning algorithm CN2-that can use argumented examples in the learning process. In this work we present an application of ABCN2 in the medical domain which deals with severe bacterial infections in geriatric population. The elderly population, people over 65 years of age, is rapidly growing as well as the costs of treating this population. In our study, we compare ABCN2 to CN2 and show that using arguments we improve the characteristics of the model. We also report the results that C4.5, Naïve Bayes and Logistic Regression achieve in this domain.","Title: Computer Analysis of Chess Champions\nYear: 2006\n\nAbstract: Who is the best chess player of all time? Chess players are often interested in this question that has never been answered\n authoritatively, because it requires a comparison between chess players of different eras who never met across the board.\n In this contribution, we attempt to make such a comparison. It is based on the evaluation of the games played by the World\n Chess Champions in their championship matches. The evaluation is performed by the chess-playing program Crafty. For this purpose we slightly adapted Crafty. Our analysis takes into account the differences in players’ styles to compensate the fact that calm positional players in\n their typical games have less chance to commit gross tactical errors than aggressive tactical players. Therefore, we designed\n a method to assess the difficulty of positions. Some of the results of this computer analysis might be quite surprising. Overall,\n the results can be nicely interpreted by a chess expert.","Title: Why minimax works: an alternative explanation\nYear: 2005\n\nAbstract: In game-playing programs relying on the minimax principle, deeper searches generally produce better evaluations. Theoretical analyses, however, suggest that in many cases minimaxing amplifies the noise introduced by the heuristic function used to evaluate the leaves of the game tree, leading to what is known as pathological behavior, where deeper searches produce worse evaluations. In most of the previous research, positions were evaluated as losses or wins. Dependence between the values of positions close to each other was identified as the property of realistic game trees that eliminates the pathology and explains why minimax is successful in practice. In this paper we present an alternative explanation that does not rely on value dependence. We show that if real numbers are used for position values, position values tend to be further apart at lower levels of the game tree, which leads to a larger proportion of more extreme positions, where error is less probable. Decreased probability of error in searches to greater depths is sufficient to eliminate the pathology and no additional properties of game trees are required.","Title: Elicitation of neurological knowledge with argument-based machine learning.\nYear: 2013\n\nAbstract: The paper describes the use of expert's knowledge in practice and the efficiency of a recently developed technique called argument-based machine learning (ABML) in the knowledge elicitation process. We are developing a neurological decision support system to help the neurologists differentiate between three types of tremors: Parkinsonian, essential, and mixed tremor (comorbidity). The system is intended to act as a second opinion for the neurologists, and most importantly to help them reduce the number of patients in the \"gray area\" that require a very costly further examination (DaTSCAN). We strive to elicit comprehensible and medically meaningful knowledge in such a way that it does not come at the cost of diagnostic accuracy.To alleviate the difficult problem of knowledge elicitation from data and domain experts, we used ABML. ABML guides the expert to explain critical special cases which cannot be handled automatically by machine learning. This very efficiently reduces the expert's workload, and combines expert's knowledge with learning data. 122 patients were enrolled into the study.The classification accuracy of the final model was 91%. Equally important, the initial and the final models were also evaluated for their comprehensibility by the neurologists. All 13 rules of the final model were deemed as appropriate to be able to support its decisions with good explanations.The paper demonstrates ABML's advantage in combining machine learning and expert knowledge. The accuracy of the system is very high with respect to the current state-of-the-art in clinical practice, and the system's knowledge base is assessed to be very consistent from a medical point of view. This opens up the possibility to use the system also as a teaching tool.","Title: Quantifying and Visualizing Attribute Interactions\nYear: 2003\n\nAbstract: Interactions are patterns between several attributes in data that cannot be\ninferred from any subset of these attributes. While mutual information is a\nwell-established approach to evaluating the interactions between two\nattributes, we surveyed its generalizations as to quantify interactions between\nseveral attributes. We have chosen McGill's interaction information, which has\nbeen independently rediscovered a number of times under various names in\nvarious disciplines, because of its many intuitively appealing properties. We\napply interaction information to visually present the most important\ninteractions of the data. Visualization of interactions has provided insight\ninto the structure of data on a number of domains, identifying redundant\nattributes and opportunities for constructing new features, discovering\nunexpected regularities in data, and have helped during construction of\npredictive models; we illustrate the methods on numerous examples. A machine\nlearning method that disregards interactions may get caught in two traps:\nmyopia is caused by learning algorithms assuming independence in spite of\ninteractions, whereas fragmentation arises from assuming an interaction in\nspite of independence.","Title: Refining Complete Hypotheses in ILP\nYear: 1999\n\nAbstract: Most ILP systems employ the covering algorithm whereby hypotheses are constructed iteratively clause by clause. Typically the covering algorithm is greedy in the sense that each iteration adds the best clause according to some local evaluation criterion. Some typical problems of the covering algorithm are: unnecessarily long hypotheses, difficulties in handling recursion, difficulties in learning multiple predicates. This paper investigates a non-covering approach to ILP, implemented as a Prolog program called HYPER, whose goals were: use intensional background knowledge, handle recursion well, and enable multi-predicate learning. Experimental results in this paper may appear surprising in the view of the very high combinatorial complexity of the search space associated with the non-covering approach.","Title: Problem Decomposition for Behavioural Cloning\nYear: 2000\n\nAbstract: In behavioural cloning of the human operator's skill, a controller is usually induced directly as a classifier from system's states into actions. Experience shows that this often results in brittle controllers. In this paper we explore a decomposition of the cloning problem into two learning problems: the learning of operator's control trajectories and the learning of the system's dynamics separately. We analyse advantages of such indirect controllers. We give characterization of the learner's error that is plausible explanation of why this decomposition approach has empirically proved to be usually superior to direct cloning.","Title: Machine learning in artificial intelligence\nYear: 1993\n\nAbstract: Among several forms of learning, learning concepts from examples is the most common and best understood. In this paper some approaches to learning concepts from examples are reviewed. In particular those approaches that are currently most important with respect to practical applications (learning decision trees and if-then rules), or likely to become very important in the near future (Inductive Logic Programming as a form of relational learning) are discussed.","Title: Machine Learning by Function Decomposition\nYear: 1997\n\nAbstract: We present a new machine learning method that, given a set of training examples, induces a denition of the target concept in terms of a hierarchy of intermediate concepts and their denitions. This eectively decomposes the problem into smaller, less complex problems. The method is inspired by the Boolean func- tion decomposition approach to the design of digital circuits. To cope with high time complexity of nding an optimal decomposi- tion, we propose a suboptimal heuristic al- gorithm. The method, implemented in pro- gram HINT (HIerarchy Induction Tool), is ex- perimentally evaluated using a set of arti- cial and real-world learning problems. It is shown that the method performs well both in terms of classication accuracy and discovery of meaningful concept hierarchies.","Title: Search versus Knowledge: An Empirical Study of Minimax on KRK\nYear: 2003\n\nAbstract: This article presents the results of an empirical experiment designed to gain insight into what is the effect of the minimax algorithm on the evaluation function. The experiment's simulations were performed upon the KRK chess endgame. Our results show that dependencies between evaluations of sibling nodes in a game tree and an abundance of possibilities to commit blunders present in the KRK endgame are not sufficient to explain the success of the minimax principle in practical game-playing as was previously believed. The article shows that minimax in combination with a noisy evaluation function introduces a bias into the backed-up evaluations and argues that this bias is what masked the effectiveness of the minimax. in previous studies.","Title: VizRank: Data Visualization Guided by Machine Learning\nYear: 2006\n\nAbstract: Data visualization plays a crucial role in identifying interesting patterns in exploratory data analysis. Its use is, however, made difficult by the large number of possible data projections showing different attribute subsets that must be evaluated by the data analyst. In this paper, we introduce a method called VizRank, which is applied on classified data to automatically select the most useful data projections. VizRank can be used with any visualization method that maps attribute values to points in a two-dimensional visualization space. It assesses possible data projections and ranks them by their ability to visually discriminate between classes. The quality of class separation is estimated by computing the predictive accuracy of k-nearest neighbor classifier on the data set consisting of x and y positions of the projected data points and their class information. The paper introduces the method and presents experimental results which show that VizRank's ranking of projections highly agrees with subjective rankings by data analysts. The practical use of VizRank is also demonstrated by an application in the field of functional genomics.","Title: Using machine learning techniques to interpret results from discrete event simulation\nYear: 1994\n\nAbstract: This paper describes an approach to the interpretation of discrete event simulation results using machine learning techniques. The results of two simulators were processed as machine learning problems. Interpretation obtained by the regression tree learning system Retis was intuitive but obviously expressed in a complicated way. To enable a more powerful knowledge representation, Inductive Logic Programming (ILP) system Markus was used, that also highlighted some attribute combinations. These attribute combinations were used as new attributes in further experiments with Retis and Assistant. Some interesting regularities were thereby automatically discovered.","Title: Learning by discovering concept hierarchies\nYear: 1999\n\nAbstract: We present a new machine learning method that, given a set of training examples, induces a definition of the target concept in terms of a hierarchy of intermediate concepts and their definitions. This effectively decomposes the problem into smaller, less complex problems. The method is inspired by the Boolean function decomposition approach to the design of switching circuits. To cope with high time complexity of finding an optimal decomposition, we propose a suboptimal heuristic algorithm. The method, implemented in program HINT(Hierarchy INduction Tool), is experimentally evaluated using a set of artificial and real-world learning problems. In particular, the evaluation addresses the generalization property of decomposition and its capability to discover meaningful hierarchies. The experiments show that HINT performs well in both respects. (C) 1999 Elsevier Science B.V. All rights reserved.","Title: On estimating probabilities in tree pruning\nYear: 1991\n\nAbstract: In this paper we introduce a new method for decision tree pruning, based on the minimisation of the expected classification error method by Niblett and Bratko. The original Niblett-Bratko pruning algorithm uses Laplace probability estimates. Here we introduce a new, more general Bayesian approach to estimating probabilities which we call m-probability-estimation. By varying a parameter m in this method, tree pruning can be adjusted to particular properties of the learning domain, such as level of noise. The resulting pruning method improves on the original Niblett-Bratko pruning in the following respects: apriori probabilities can be incorporated into error estimation, several trees pruned to various degrees can be generated, and the degree of pruning is not affected by the number of classes. These improvements are supported by experimental findings. m-probability-estimation also enables the combination of learning data obtained from various sources.","Title: Why is rule learning optimistic and how to correct it\nYear: 2006\n\nAbstract: In their search through a huge space of possible hypotheses, rule induction algorithms compare estimations of qualities of a large number of rules to find the one that appears to be best. This mechanism can easily find random patterns in the data which will – even though the estimating method itself may be unbiased (such as relative frequency) – have optimistically high quality estimates. It is generally believed that the problem, which eventually leads to overfitting, can be alleviated by using m-estimate of probability. We show that this can only partially mend the problem, and propose a novel solution to making the common rule evaluation functions account for multiple comparisons in the search. Experiments on artificial data sets and data sets from the UCI repository show a large improvement in accuracy of probability predictions and also a decent gain in AUC of the constructed models.","Title: Discovery of abstract concepts by a robot\nYear: 2010\n\nAbstract: This paper reviews experiments with an approach to discovery through robot’s experimentation in its environment. In addition\n to discovering laws that enable predictions, we are particularly interested in the mechanisms that enable the discovery of\n abstract concepts that are not explicitly observable in the measured data, such as the notions of a tool or stability. The\n approach is based on the use of Inductive Logic Programming. Examples of actually discovered abstract concepts in the experiments\n include the concepts of a movable object, an obstacle and a tool.","Title: Skill reconstruction as induction of LQ controllers with subgoals\nYear: 1997\n\nAbstract: Controlling a complex dynamic system, such as a plane or a crane, usually requires a skilled operator. Such a control skill is typically hard to reconstruct through introspection. Therefore an attractive approach to the reconstruction of control skill involves machine learning from operators' control traces, also known as behavioural cloning. In the most common approach to behavioural cloning, a controller is induced in the form of a rule set or a decision or regression tree that maps system states to actions. Unfortunately, induced controllers usually suffer from lack of robustness and lack typical elements of human control strategies, such as subgoals and substages of the control plan. In this paper we present a new approach to behavioural cloning which involves the induction of a model of the controlled system and enables the identification of subgoals that the operator is pursuing at various stages of the execution trace. The underlying formal basis for the present approach to behavioural cloning is the theory of LQ controllers. Experimental results show that this approach greatly improves the robustness of the induced controllers and also offers a new way of understanding the operator's subcognitive skill.","Title: Search versus knowledge revisited again\nYear: 2006\n\nAbstract: The questions focusing on diminishing returns for additional search effort have been a burning issue in computer chess. Despite a lot of research in this field, there are still some open questions, e.g., what happens at search depths beyond 12 plies, and what is the effect of the program's knowledge on diminishing returns? The paper presents an experiment that attempts to answer these questions. The results (a) confirm that diminishing returns in chess exist, and more importantly (b) show that the amount of knowledge a program has influences when diminishing returns will start to manifest themselves.","Title: When is it better not to look ahead?\nYear: 2010\n\nAbstract: In situations where one needs to make a sequence of decisions, it is often believed that looking ahead will help produce better decisions. However, it was shown 30 years ago that there are ''pathological'' situations in which looking ahead is counterproductive. Two long-standing open questions are (a) what combinations of factors have the biggest influence on whether lookahead pathology occurs, and (b) whether it occurs in real-world decision-making. This paper includes simulation results for several synthetic game-tree models, and experimental results for three well-known board games: two chess endgames, kalah (with some modifications to facilitate experimentation), and the 8-puzzle. The simulations show the interplay between lookahead pathology and several factors that affect it; and the experiments confirm the trends predicted by the simulation models. The experiments also show that lookahead pathology is more common than has been thought: all three games contain situations where it occurs.","Title: A Dataset Decomposition Approach to Data Mining and Machine Discovery\nYear: 1997\n\nAbstract: We present a novel data mining approach basedon decomposition. In order to analyze a givendataset, the method decomposes it to a hierarchyof smaller and less complex datasets that canbe analyzed independently. The method is experimentallyevaluated on a real-world housingloans allocation dataset, showing that the decompositioncan (1) discover meaningful intermediateconcepts, (2) decompose a relatively complexdataset to datasets that are easy to analyze andcomprehend, and (3) derive a...","Title: Learning long-term chess strategies from databases\nYear: 2006\n\nAbstract: We propose an approach to the learning of long-term plans for playing chess endgames. We assume that a computer-generated database for an endgame is available, such as the king and rook vs. king, or king and queen vs. king and rook endgame. For each position in the endgame, the database gives the \"value\" of the position in terms of the minimum number of moves needed by the stronger side to win given that both sides play optimally. We propose a method for automatically dividing the endgame into stages characterised by different objectives of play. For each stage of such a game plan, a stage-specific evaluation function is induced, to be used by minimax search when playing the endgame. We aim at learning playing strategies that give good insight into the principles of playing specific endgames. Games played by these strategies should resemble human expert's play in achieving goals and subgoals reliably, but not necessarily as quickly as possible.","Title: Dynamic system simulation with qualitative differential equations\nYear: 1992\n\nAbstract: Qualitative differential equations (QDE) are a popular formalism for modelling dynamic systems qualitatively. This paper briefly introduces the basic concepts of this approach, including types of constraints used in QDE and the QSIM simulation algorithm. It also discusses the relation of QSIM to other approaches to qualitative modelling, such as confluences and Qualitative Physics Theory, and the advantages and limitations of QSIM. Selected annotated bibliography is also given.","Title: Web-Enabled Knowledge-Based Analysis of Genetic Data\nYear: 2001\n\nAbstract: We present a web-based implementation of GenePath, an intelligent assistant tool for data analysis in functional genomics. GenePath considers mutant data and uses expert-defined patterns to find gene-to-gene or gene-to-outcome relations. It presents the results of analysis as genetic networks, wherein a set of genes has various influence on one another and on a biological outcome. In the paper, we particularly focus on its web-based interface and explanation mechanisms.","Title: Independent-valued minimax: Pathological or beneficial?\nYear: 2012\n\nAbstract: Minimax search, which is used by most game-playing programs, is considered pathological when deeper searches produce worse evaluations than shallower ones. This phenomenon was first observed in theoretical analyses under seemingly reasonable conditions. It was most commonly explained by the lack of dependence between nearby positions in the analyses: if nearby positions have similar values, as is typically the case in real games, the pathology no longer occurs. In this paper, we show that the pathology can be eliminated even without position-value dependence, by assigning enough different values to the positions and modeling the heuristic error as normally distributed noise that is independent of the depth in the game tree. This leads to the conclusion that minimax is less prone to the pathology than was previously thought and indicates the importance of the number of different position values.","Title: An Experiment in Robot Discovery with ILP\nYear: 2008\n\nAbstract: We describe an experiment in the application of ILP to autonomous discovery in a robotic domain. An autonomous robot is performing experiments in its world, collecting data and formulating predictive theories about this world. In particular, we are interested in the robot's \"gaining insights\" through predicate invention. In the first experimental scenario in a pushing blocks domain, the robot discovers the notion of objects' movability. The second scenario is about discovering the notion of obstacle. We describe experiments with a simulated robot, as well as an experiment with a real robot when robot's observations contain noise.","Title: Improving vehicle aeroacoustics using machine learning\nYear: 2012\n\nAbstract: This paper presents a new approach to improving the overall aeroacoustic comfort of a vehicle, an important feature of vehicle design. The traditional improvement process is extended to benefit extensively from machine learning, information retrieval and information extraction technologies to assist the wind tunnel engineers with difficult tasks. The paper first describes the general approach and then focuses on providing a detailed description of the most important task of assessing the degree of discomfort for a human caused by wind noise in a vehicle, when the noise spectrum is known. For this purpose a novel approach of learning linear regression models that are consistent with expert's domain knowledge is presented. The results of the end user evaluation of the entire system are also presented to reflect the strengths of this approach.","Title: GenePath: a system for automated construction of genetic networks from mutant data.\nYear: 2003\n\nAbstract: Motivation: Genetic networks are often used in the analysis of biological phenomena. In classical genetics, they are constructed manually from experimental data on mutants. The field lacks formalism to guide such analysis, and accounting for all the data becomes complicated when large amounts of data are considered. Results: We have developed GenePath, an intelligent assistant that automates the analysis of genetic data. GenePath employs expert-defined patterns to uncover gene relations from the data, and uses these relations as constraints in the search for a plausible genetic network. GenePath formalizes genetic data analysis, facilitates the consideration of all the available data in a consistent manner, and the examination of the large number of possible consequences of planned experiments. It also provides an explanation mechanism that traces every finding to the pertinent data.","Title: Learning qualitative models from numerical data: extended abstract\nYear: 2013\n\nAbstract: Qualitative models are predictive models that describe how changes in values of input variables affect the output variable in qualitative terms, e.g. increasing or decreasing. We describe Padé, a new method for qualitative learning which estimates partial derivatives of the target function from training data and uses them to induce qualitative models of the target function. We formulated three methods for computation of derivatives, all based on using linear regression on local neighbourhoods. The methods were empirically tested on artificial and real-world data. We also provide a case study which shows how the developed methods can be used in practice.","Title: Learning Positional Features for Annotating Chess Games: A Case Study\nYear: 2008\n\nAbstract: By developing an intelligent computer system that will provide commentary of chess moves in a comprehensible, user-friendly, and instructive way, we are trying to use the power demonstrated by the current chess engines for tutoring chess and for annotating chess games. In this paper, we point out certain differences between the computer programs which are specialized for playing chess and our program which is aimed at providing quality commentary. Through a case study, we present an application of argument-based machine learning, which combines the techniques of machine learning and expert knowledge, to the construction of more complex positional features, in order to provide our annotating system with an ability to comment on various positional intricacies of positions in the game of chess.","Title: Likelihood based classification in Bayesian networks\nYear: 2007\n\nAbstract: Learning directed probabilistic networks from data and using them for classification purposes is a well known problem. Many learning algorithms have been shown to be successful for various kinds of learning scenarios. Basically they all generate a single network from data, which is then used for classification purposes and possible domain understanding. In this paper we propose a simple method for inferring a model consisting of several Bayesian networks, each one representing data of one class. The data is divided into class subsets and from each subset a separate Bayesian network is learnt. Classification is done using prior and posterior probability distribution information in all networks. We thoroughly tested the proposed method on synthetic data and several repository datasets and compared it to other machine learning methods, to prove its effectiveness. We argue that with smaller modifications, the method can be used for learning from censored survival domains.","Title: Improving Numerical Prediction with Qualitative Constraints\nYear: 2003\n\nAbstract: The usual numerical learning methods, that are primarily concerned with finding a good numerical fit to the data, often make predictions that do not correspond to the qualitative mechanisms in the domain of modelling or a domain expert's intuition. Consistency of numerical predictions with a given qualitative model is helpful when a numerical model is used for explanation of phenomena in the modelled domain, but can also considerably improve numerical accuracy. In this paper we present a novel approach to numerical machine learning called Qfilter. Qfilter is a numerical regression method that can take into account qualitative background knowledge to give qualitatively faithful numerical prediction. The results on a set of domains including population dynamics show considerable prediction accuracy improvements compared to the usual numerical learners. As qualitative domain knowledge is often available in practice, Qfilter's ability to exploit such knowledge should be beneficial in many applications.","Title: A knowledge base for finite element mesh design\nYear: 1994\n\nAbstract: The finite element method (FEM) is the most successful numerical method, that is used extensively by engineers to analyse stresses and deformations in physical structures. These structures should be represented as a finite element mesh. Defining an appropriate geometric mesh model that ensures low approximation errors and avoids unnecessary computational overheads is a very difficult and time consuming task. It is the major bottleneck in the FEM analysis process. The inductive logic programming system GOLEM has been employed to construct the rules for deciding about the appropriate mesh resolution. Five cylindrical mesh models have been used as a source of training examples. The evaluation of the resulting knowledge base shows that conditions in the domain are well represented by the rules, which specify the required number of the finite elements on the edges of the structures to be analysed using FEM. A comparison between the results obtained by this knowledge base and conventional mesh generation techniques confirms that the application of inductive logic programming is an effective approach to solving the problem of mesh design.","Title: Dex Methodology: Three Decades Of Qualitative Multi-Attribute Modeling\nYear: 2013\n\nAbstract: DEX is a qualitative multi-attribute decision modeling methodology that integrates multi-criteria decision modeling with rule-based expert systems. The method was conceived in 1979. Since, it has been continuously developed and implemented in a wide range of computer programs that have been applied in hundreds of practical decision-making studies. Here we present its main methodological concepts, contributions to the theory and practice of decision support, and outline a history of its development and evolution.","Title: VizRank: finding informative data projections in functional genomics by machine learning.\nYear: 2005\n\nAbstract: VizRank is a tool that finds interesting two-dimensional projections of class-labeled data. When applied to multi-dimensional functional genomics datasets, VizRank can systematically find relevant biological patterns.http://www.ailab.si/supp/bi-vizrankhttp://www.ailab.si/supp/bi-vizrank.","Title: GenePath: a system for inference of genetic networks and proposal of genetic experiments.\nYear: 2003\n\nAbstract: A genetic network is a formalism that is often used in biology to represent causalities and reason about biological phenomena related to genetic regulation. We present GenePath, a computer-based system that supports the inference of genetic networks from a set of genetic experiments. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on background knowledge and experimental results. Additionally, it can propose genetic experiments that may further refine the discovered network and establish relations between genes that could not be related based on the original experimental data. We illustrate GenePath's approach and utility on analysis of data on aggregation and sporulation of the soil amoeba Dictyostelium discoideum.","Title: Q2 Learning and Its Application to Car Modelling\nYear: 2006\n\nAbstract: In this paper we describe an application of Q(2) learning, a recently developed approach to machine learning in numerical domains (Suc et al., 2003, 2004) to the automated modelling of a complex, industrially relevant mechanical system - a four wheel suspension and steering system of a car. In this experiment, first a qualitative model of this dynamic system was induced from data, and then this model was reified into a quantitative model. The induced qualitative models enable explanation of relations among the variables in the system and, when reified into quantitative models, enable accurate numerical prediction. Furthermore, the qualitative guidance of the quantitative modelling process leads to predictions that are significantly more accurate than those obtained by state-of-the-art numerical learning methods.","Title: Qualitative Simulation with Answer Set Programming.\nYear: 2014\n\nAbstract: Qualitative Simulation (QSIM) reasons about the behaviour of dynamic physical systems as they evolve over time. The system is represented by a coarse qualitative model rather than precise numerical models. However, for large complex domains, such as robotics for Urban Search and Rescue, existing QSIM implementations are inefficient. ASPQSIM is a novel formulation of the QSIM algorithm in Answer Set Programming that takes advantage of the similarities between qualitative simulation and constraint satisfaction problems. ASPQSIM is compared against an existing QSIM implementation on a variety of domains that demonstrate ASPQSIM provides a significant improvement in efficiency especially on complex domains, and producing simulations in domains that are not solvable by the procedural implementation.","Title: Feature transformation by function decomposition\nYear: 1998\n\nAbstract: The function decomposition described can identify subsets of existing features and discover nongiven functions that map these subsets to a new feature, also, it can organize the existing and new features into a hierarchy. The authors demonstrate their Hierarchy Induction Tool (HINT) system on a housing loan-allocation application. Methods for switching circuit design often implicitly deal with feature transformation. Such methods construct a circuit to implement a given or partially given tabulated Boolean function. The authors' function-decomposition method can discover and construct a hierarchy of new features that one can add to the original dataset or transform into a hierarchy of less complex datasets. The method allows the decomposition to deal with nominal-feature (that is, not necessarily binary) functions","Title: Qualitative Planning of Object Pushing by a Robot.\nYear: 2015\n\nAbstract: Pushing is often used by robots as a simple way to manipulate the environment and has in the past been well studied from kinematic and numerical perspective. The paper proposes a qualitative approach to pushing convex polygonal objects by a simple wheeled robot through a single point contact. We show that by using qualitative reasoning, pushing dynamics can be described in concise and intuitive manner, that is still sufficient to control the robot to successfully manipulate objects. Using the QUIN program on numerical data collected by our robot while experimentally pushing objects of various shapes, we induce a model of pushing. This model is then used by our planning algorithm to push objects of previously unused shapes to given goal configurations. The produced trajectories are compared to smooth geometric solutions. Results show the correctness of our qualitative model of pushing and efficiency of the planning algorithm.","Title: Extracting qualitative relations from categorical data.\nYear: 2016\n\nAbstract: Qualitative modeling is traditionally concerned with the abstraction of numerical data. In numerical domains, partial derivatives describe the relation between the independent and dependent variable; qualitatively, they tell us the trend of the dependent variable. In this paper, we address the problem of extracting qualitative relations in categorical domains. We generalize the notion of partial derivative by defining the probabilistic discrete qualitative partial derivative (PDQ PD). PDQ PD is a qualitative relation between the target class c and the discrete attribute; the derivative corresponds to ordering the attribute's values, a i , by P ( c | a i ) in a local neighborhood of the reference point, respecting the ceteris paribus principle. We present an algorithm for computation of PDQ PD from labeled attribute-based training data. Machine learning algorithms can then be used to induce models that explain the influence of the attribute's values on the target class in different subspaces of the attribute space.","Title: Reactive Motion Planning with Qualitative Constraints.\nYear: 2017\n\nAbstract: Qualitative modeling tends to be closer to human type of reasoning than traditional numerical modeling and proved to be very useful in certain branches of cognitive robotics. However, due to the lack of precise numerical relations, planning with qualitative models has been achieved to a limited extent. Typically, it is bound to predicting possible future behaviors of the system, and demands additional exploration of numerical relations, before constructed plans can be executed. In this paper we show how qualitative models can be interpreted in terms of reactive planning, to produce executable actions without the need for additional numerical learning. We demonstrate our method on two classical motion planning problems – pursuing and obstacle avoidance, and a complex problem of pushing objects.","Title: Feasibility of spirography features for objective assessment of motor function in Parkinson's disease.\nYear: 2017\n\nAbstract: •A method for self-monitoring the motor function in Parkinson's disease is presented.•Slowness of movement (bradykinesia) is typically associated with under-medication.•Involuntary movements (dyskinesia) can be the result of over-medication.•A machine learning model that detects bradykinesia and dyskinesia is proposed.•The model's visual explanatory power is evaluated.","Title: Using Heuristic-Search Based Engines for Estimating Human Skill at Chess.\nYear: 2011\n\nAbstract: Establishing heuristic-search based chess programs as appropriate tools for estimating human skill levels at chess may seem impossible due to the following issues: the programs' evaluations and decisions tend to change with the depth of search and with the program used. In this research, we provide an analysis of the differences between heuristic-search based programs in estimating chess skill. We used four different chess programs to perform analyses of large data sets of recorded human decisions, and obtained very similar rankings of skill-based performances of selected chess players using any of these programs at various levels of search. A conclusion is that, given two chess players, all the programs unanimously rank one player to be clearly stronger than the other, or all the programs assess their strengths to be similar. We also repeated our earlier analysis with the program CRAFTY of the human World Chess Champions with currently one of the strongest chess programs, RYBKA 3(2), and obtained qualitatively very similar results as with CRAFTY. This speaks in favour of computer heuristic search being adequate for estimating skill levels of chess players, despite the above stated issues.","Title: Alphazero - What'S Missing?\nYear: 2018\n\nAbstract: In December 2017, the game playing program AlphaZero was reported to have learned in less than 24 hours to play each of the games of chess, Go and shogi better than any human, and better than any other existing specialised computer program for these games. This was achieved just by self-play, without access to any knowledge of these games other than the rules of the game. In this paper we consider some limitations to this spectacular success. The program was trained in well-defined and relatively small domains (admittedly with enormous combinatorial complexity) compared to many real world problems, and it was possible to generate large amounts of learning data through simulated games which is typically not possible in real life domains. When it comes to understanding the games played by AlphaZero, the program's inability to explain its games and the knowledge acquired in human-understandable terms is a serious limitation.","Title: Identifying typical approaches and errors in Prolog programming with argument-based machine learning.\nYear: 2018\n\nAbstract: •Abstract-syntax-tree (AST) patterns as attributes for classifying Prolog programs.•Identification of AST patterns for detecting errors and programming approaches.•An argument-based algorithm for learning rules suitable for tutoring.•Evaluation of extracted patterns and rules on 42 Prolog exercises.","Title: A Machine Learning System For Controlling A Rescue Robot\nYear: 2017\n\nAbstract: Many rescue robots are reconfigurable, having subtracks (or flippers) that can be adjusted to help the robot traverse different types of terrain. Knowing how to adjust them requires skill on the part of the operator. If the robot is intended to run autonomously, the control system must have an understanding of how the flippers affect the robot's interaction with the ground. We describe a system that first learns the effects of a robot's actions and then uses this knowledge to plan how to reconfigure the robot's tracks so that it can overcome different types of obstacles. The system is a hybrid of qualitative symbolic learning and reinforcement learning.","Title: Extreme value correction: a method for correcting optimistic estimations in rule learning\nYear: 2019\n\nAbstract: Machine learning algorithms rely on their ability to evaluate the constructed hypotheses for choosing the optimal hypothesis during learning and assessing the quality of the model afterwards. Since these estimates, in particular the former ones, are based on the training data from which the hypotheses themselves were constructed, they are usually optimistic. The paper shows three different solutions; two for the artificial boundary cases with the smallest and the largest optimism and a general correction procedure called extreme value correction (EVC) based on extreme value distribution. We demonstrate the application of the technique to rule learning, specifically to estimating classification accuracy of a single rule, and evaluate it on an artificial data set and on a number of UCI data sets. We observed that the correction successfully improved the accuracy estimates. We also describe an approach for combining rules into a linear global classifier and show that using EVC estimates leads to more accurate classifiers.","Title: Learning from noisy data using a non-covering ILP algorithm\nYear: 2010\n\nAbstract: In this paper we describe the non-covering inductive logic programming program HYPER/N, concentrating mainly on noise handling as well as some other mechanisms that improve learning. We perform some experiments with HYPER/N on synthetic weather data with artificially added noise, and on real weather data to learn to predict the movement of rain from radar rain images and synoptic data.","Title: Using Machine Learning to Understand Operator's Skill\nYear: 2002\n\nAbstract: Controlling complex dynamic systems requires skills that operators often cannot completely describe, but can demonstrate. This paper describes research into the understanding of such tacit control skills. Understanding tacit skills has practical motivation in respect of communicating skill to other operators, operator training, and also mechanising and optimising human skill. This paper is concerned with approaches whereby, using techniques of machine learning, controllers that emulate the human operators are generated from examples of control traces. This process is also called \"behavioural cloning\". The paper gives a review of ML-based approaches to behavioural cloning, representative experiments, and an assessment of the results. Some recent work is presented with particular emphasis on understanding human tacit skill, and generating explanation of how it works. This includes the extraction of the operator's subconscious sub-goals and the use of qualitative control strategies. We argue for qualitative problem representations and decomposition of the machine learning problem involved.","Title: Multiobjective discovery of human-like driving strategies\nYear: 2017\n\nAbstract: Human driving models aim at producing human-like driving strategies by mimicking the behavior of drivers. Drivers optimize several objectives when traveling along a route, such as the traveling time and the fuel consumption. However, these objectives are not taken into account when building human driving models. To overcome this shortcoming, we designed a two-level Multiobjective Optimization algorithm for discovering Human-like Driving Strategies (MOHDS) that combines the human driving models with the optimization of the traveling time and the fuel consumption. Consequently, MOHDS enables to simultaneously mimic human driving behavior and optimize relevant driving objectives. MOHDS was tested on a two-lane rural route and compared to the existing approaches for human driving modeling. The results show that, unlike the existing approaches, MOHDS finds the driving strategies with various tradeoffs between the objectives.","Title: Rewrite Rules for Debugging Student Programs in Programming Tutors.\nYear: 2018\n\nAbstract: Data-driven intelligent tutoring systems learn to provide feedback based on past student behavior, reducing the effort required for their development. A major obstacle to applying data-driven methods in the programming domain is the lack of meaningful observable actions for describing the students problem-solving process. We propose rewrite rules as a language-independent formalization of programm...","Title: Influence of Search Depth on Position Evaluation.\nYear: 2017\n\nAbstract: By using a well-known chess program and a large data set of chess positions from real games we demonstrate empirically that with increasing search depth backed-up evaluations of won positions tend to increase, while backed-up evaluations of lost positions tend to decrease. We show three implications of this phenomenon in practice and in the theory of computer game playing. First, we show that heuristic evaluations obtained by searching to different search depths are not directly comparable. Second, we show that fewer decision changes with deeper search are a direct consequence of this property of heuristic evaluation functions. Third, we demonstrate that knowing this property may be used to develop a method for detecting fortresses in chess, which is an unsolved task in computer chess.","Title: Learning Explainable Control Strategies Demonstrated on the Pole-and-Cart System.\nYear: 2019\n\nAbstract: The classical problem of balancing an inverted pendulum is commonly used to evaluate control learning techniques. Traditional learning methods aim to improve the performance of the learned controller, often disregarding comprehensibility of the learned control policies. Recently, Explainable AI (XAI) has become of great interest in the areas where humans can benefit from insights discovered by AI, or need to check whether AI's decisions make sense. Learning qualitative models allows formulation of learned hypotheses in a comprehensible way, closer to human intuition than traditional numerical learning. In this paper, we use a qualitative approach to learning control strategies, which we demonstrate on the problem of balancing an inverted pendulum. We use qualitative induction to learn a qualitative model from experimentally collected numerical traces, and qualitative simulation to search for possible qualitative control strategies, which are tested through reactive execution. Successful behaviors provide a clear explanation of the learned control strategy.","Title: Identification And Conceptualization Of Procedural Chunks In Chess\nYear: 2021\n\nAbstract: When it comes to cognitive architecture and human information processing, chunks are one of the best known and most recognized constructs. Nevertheless, the nature of chunks is still very elusive, especially when it comes to chunks in procedural knowledge. This study deals with basic features of procedural information processing and examines the manifestation of chunks in procedural knowledge. The participants' task was to reconstruct sequences of chess moves. Chess was chosen as an experimental domain, because of its complexity, well-defined rules and standardized measure of chess player strength. From the results we conclude that short-term memory capacity is determined by the combination of the size and amount of procedural chunks recalled to the short-term memory. We have shown that on average, participants with more specialized knowledge operated faster and with larger chunks of procedural information than participants with less specialized knowledge. We have shown that in procedural information processing, the level of expertise and the sorting order of the retrieved information are important factors that influence the amount of procedural chunks retained in the short-term memory. Therefore, the capacity of short-term memory in complex situations cannot be expressed as a simple concept. (C) 2021 Elsevier B.V. All rights reserved.","Title: Are pre-service teachers disinclined to utilise embodied humanoid social robots in the classroom?\nYear: 2021\n\nAbstract: Teachers' readiness for technology integration depends also on their beliefs about the contribution of technology to teaching and learning, which influence their motivation for its adoption. Initial pre-service teacher education is critical in reducing the attitude-behaviour divide supporting technology acceptability, acceptance and use. Acceptance of interaction between human and robot is more complicated than human-computer interaction acceptance. Social robots are radical innovations, harder for potential users to accept in human social spaces than are incremental innovations. In 2019, a survey using a convenience sample of 121 first-year students was conducted to examine pre-service teachers' beliefs about social robot educational technology. It examined the following factors derived from the Unified Theory of Acceptance and Use of Technology adopted for social robots in education: Perceived social dimension, Intention to use, Perceived usability, Anxiety. Based on our findings, it seems there is a critical disjunction between researchers' efforts to equip social robots with human manners and social intelligence and participants' rejection of this technology precisely because it mimics being human. Further, we report that ICT familiarity as assessed using PISA's Information Communication Technology-ICT familiarity factors is related to robot acceptability. These findings need further examination to inform educational robotics design and Human-Robot Interaction research and teacher education and training. Practitioners notes What is already known about this topic In the age of robotic technology, teachers face requirements to prepare students for work and life with social robots. Social robots are tested for classroom integration. Teachers' readiness to implement robot lessons depends on their beliefs about social robotic technology's contribution to teaching. Research and development in the field of social robotics still tend to focus more frequently on technology applications rather than pedagogical issues and advancing teaching and learning. What this paper adds Participants refuse to accept the idea of social robot-based instruction. The identified belief pattern is based mainly on the perceived social dimension, intention to use, perceived usability and anxiety. Participants critically perceive the robot's social dimension. Some of PISA's ICT familiarity factors are related to robots acceptability factors. Implication for policy and/or practice The policy and practice need to address how social robots could be integrated into current teaching and learning practices and more importantly how could robotic technology facilitate innovative pedagogical models for effective and efficient learning. The introduction of social robots should follow instructional design requirements and not merely technological advancement. Teacher initial education has to provide social robotic learning environments for pre-service teachers to experiment and design."],"string":"[\n \"Title: LRTA\\nYear: 2008\\n\\nAbstract: Recently we showed that under very reasonable conditions, incomplete, real-time search methods like RTA* work better with pessimistic heuristic functions than with optimistic, admissible heuristic functions of equal quality. The use of pessimistic heuristic function,; results in higher percentage of correct decisions and in shorter solution lengths. We extend this result to learning RTA* (LRTA*) and demonstrate that the use of pessimistic instead of optimistic (or mixed) heuristic functions of equal quality results in much faster learning process at the cost of just marginally worse quality of converged solutions.\",\n \"Title: Analyzing Attribute Dependencies\\nYear: 2003\\n\\nAbstract: Many effective and efficient learning algorithms assume independence of attributes. They often perform well even in domains where this assumption is not really true. However, they may fail badly when the degree of attribute dependencies becomes critical. In this paper, we examine methods for detecting deviations from independence. These dependencies give rise to \\\"interactions\\\" between attributes which affect the performance of learning algorithms. We first formally define the degree of interaction between attributes through the deviation of the best possible \\\"voting\\\" classifier from the true relation between the class and the attributes in a domain. Then we propose a practical heuristic for detecting attribute interactions, called interaction gain. We experimentally investigate the suitability of interaction gain for handling attribute interactions in machine learning. We also propose visualization methods for graphical exploration of interactions in a domain.\",\n \"Title: Automated Chess Tutor\\nYear: 2006\\n\\nAbstract: While recently the strength of chess playing programs has grown immensely, their capability of explaining in human understand- able terms why some moves are good or bad has enjoyed little attention. Progress towards programs' ability to intelligently comment chess games, played either by the program or human, has been negligible in compari- son with their playing strength. Typical style of program's \\\\comments\\\" in terms of the best variations and their numerical scores is of little use to a human who wants to learn important concepts behind these vari- ations. In this paper, we present some core mechanisms for automated commenting in terms of relevant goals to be achieved or preserved in a given position. By combining these mechanisms with an actual chess en- gine we were able to transform this engine into a chess tutor/annotator that is capable of generating rather intelligent commentary. The main advantage of our work over related approaches is: (a) ability to tutor the whole game of chess, and (b) relatively solid understanding and com- menting of positional aspects of positions.\",\n \"Title: First Order Regression\\nYear: 1997\\n\\nAbstract: We present a new approach, called First Order Regression (FOR),to handling numerical information in Inductive Logic Programming (ILP).FOR is a combination of ILP and numerical regression.First-order logic descriptions are induced to carve out those subspacesthat are amenable to numerical regression among real-valued variables.The program FORS is an implementation of this idea, where numericalregression is focused on a distinguished continuous argument of the targetpredicate. We show that this can be viewed as a generalisation of theusual ILP problem. Applications of FORS on several real-world datasets are described: the prediction of mutagenicity of chemicals, themodelling of liquid dynamics in a surge tank, predicting theroughness in steel grinding, finite element mesh design, andoperator‘s skill reconstruction in electric discharge machining. Acomparison of FORS‘ performance with previous results in thesedomains indicates that FORS is an effective tool for ILP applicationsthat involve numerical data.\",\n \"Title: Learning qualitative models\\nYear: 2004\\n\\nAbstract: In general, modeling is a complex and creative task, and building qualitative models is no exception. One way of automating this task is by means of machine learning. Observed behaviors of a modeled system are used as examples for a learning algorithm that constructs a model that is consistent with the data. In this article, we review approaches to learning qualitative models, either from numeric data or qualitative observations. We describe the QUIN program that looks for qualitative patterns in numeric data and outputs the results of learning as \\\"qualitative trees.\\\" We illustrate this using applications associated with systems control, in particular, the identification and optimization of controllers and human operator's control skill. We also review approaches that learn models in terms of qualitative differential equations.\",\n \"Title: Goal-Oriented conceptualization of procedural knowledge\\nYear: 2012\\n\\nAbstract: Conceptualizing procedural knowledge is one of the most challenging tasks of building systems for intelligent tutoring. We present an algorithm that enables teachers to accomplish this task semi automatically. We used the algorithm on a difficult king, bishop, and knight versus the lone king (KBNK) chess endgame, and obtained concepts that could serve as textbook instructions. A pilot experiment with students and a separate evaluation of the instructions by experienced chess trainers were deemed very positive.\",\n \"Title: Nomograms for visualizing support vector machines\\nYear: 2005\\n\\nAbstract: We propose a simple yet potentially very effective way of visualizing trained support vector machines. Nomograms are an established model visualization technique that can graphically encode the complete model on a single page. The dimensionality of the visualization does not depend on the number of attributes, but merely on the properties of the kernel. To represent the effect of each predictive feature on the log odds ratio scale as required for the nomograms, we employ logistic regression to convert the distance from the separating hyperplane into a probability. Case studies on selected data sets show that for a technique thought to be a black-box, nomograms can clearly expose its internal structure. By providing an easy-to-interpret visualization the analysts can gain insight and study the effects of predictive factors.\",\n \"Title: Inductive Learning Applied to Program Construction and Verification\\nYear: 1992\\n\\nAbstract: In this paper we show how techniques of Inductive Logic Programming (ILP), a form of inductive learning, can be applied to some traditional problems of program development and verification. First we consider the problem of data reification when refining an abstract program specification into a more concrete one, that is one closer to the target implementation language. An ILP system is then used to automatically construct a target language program specification. Second, we apply the ILP approach to automatic construction of loop invariants in formal proofs of program correctness.\",\n \"Title: Learning qualitative models from numerical data\\nYear: 2011\\n\\nAbstract: Qualitative models describe relations between the observed quantities in qualitative terms. In predictive modelling, a qualitative model tells whether the output increases or decreases with the input. We describe Pade, a new method for qualitative learning which estimates partial derivatives of the target function from training data and uses them to induce qualitative models of the target function. We formulated three methods for computation of derivatives, all based on using linear regression on local neighbourhoods. The methods were empirically tested on artificial and real-world data. We also provide a case study which shows how the developed methods can be used in practice.\",\n \"Title: Learning qualitative models of dynamic systems\\nYear: 1991\\n\\nAbstract: A technique is described for learning qualitative models of dynamicsystems. The QSIM formalism is used as a representation forlearned qualitative models. The problem of learning QSIM-type modelsis formulated in logic, and the GOLEM learning program is usedfor induction. An experiment in learning a qualitative model of theconnected containers system, also called U-tube, is described in detail.1 IntroductionIt has been shown that qualitative models are better suited for several tasksthan ...\",\n \"Title: Engineering Applications of ILP.\\nYear: 1995\\n\\nAbstract: Several applications of Inductive Logic Programming (ILP) are presented. These belong to various areas of engineering, including\\n mechanical, environmental, software, and dynamical systems engineering. The particular applications are finite element mesh\\n design, biological classification of river water quality, data reification, inducing program invariants, learning qualitative\\n models of dynamic systems, and learning control rules for dynamic systems. A number of other applications are briefly mentioned.\\n Finally, a discussion of the advantages and disadvantages of ILP as compared to other approaches to machine learning is given.\",\n \"Title: Argument-based machine learning\\nYear: 2007\\n\\nAbstract: In this paper, some recent ideas will be presented about making machine learning (ML) more effective through mechanisms of argumentation. In this sense, argument-based machine learning (ABML) is defined as a refinement of the usual definition of ML. In ABML, some learning examples are accompanied by arguments, that are expert's reasons for believing why these examples are as they are. Thus ABML provides a natural way of introducing domain-specific prior knowledge in a way that is different from the traditional, general background knowledge. The task of ABML is to find a theory that explains the \\\"argumented\\\" examples by making reference to the given reasons. ABML, so defined, is motivated by the following advantages in comparison with standard learning from examples: (1) arguments impose constraints over the space of possible hypotheses, thus reducing search complexity, and (2) induced theories should make more sense to the expert. Ways of realising ABML by extending some existing ML techniques are discussed, and the aforementioned advantages of ABML are demonstrated experimentally.\",\n \"Title: Argument Based Rule Learning\\nYear: 2006\\n\\nAbstract: We present a novel approach to machine learning, called ABML (argumentation based ML). This approach combines machine learning from examples with concepts from the field of argumentation. The idea is to provide expert's arguments, or reasons, for some of the learning examples. We require that the theory induced from the examples explains the examples in terms of the given reasons. Thus arguments constrain the combinatorial search among possible hypotheses, and also direct the search towards hypotheses that are more comprehensible in the light of expert's background knowledge. In this paper we implement ABCN2 as an extension of the CN2 rule learning algorithm, and analyze its advantages in comparison with the original CN2 algorithm.\",\n \"Title: Implementing search heuristics using the AL1 advice-taking system\\nYear: 1979\\n\\nAbstract: The AL1 System (Advice Language 1) was developed as a vehicle for conveying expert knowledge, or advice, to a problem solver. Using chess end-games as an experimental problem domain, this paper concentrates on the question: How to implement chess heuristics using the mechanisms of AL1? The spirit of advice programming as a sort of \\\"tree-search engineering\\\" is illustrated by developing an AL1 piece-of-advice for solving an example problem from the king-knight vs. king-rook chess ending. Experiments indicate that an advice program for this ending, based on comparatively simple concepts, and the human chess master perform comparably.\",\n \"Title: Induction of Qualitative Trees\\nYear: 2001\\n\\nAbstract: We consider the problem of automatic construction of qualitative models by inductive learning from quantitative examples. We present an algorithm QUIN (QUalitative INduction) that learns qualitative trees from a set of examples described with numerical attributes. At difference with decision trees, the leaves of qualitative trees contain qualitative functional constraints as used in qualitative reasoning. A qualitative tree defines a partition of the attribute space into the areas with common qualitative behaviour of the chosen class variable. We describe a basic algorithm for induction of qualitative trees, improve it to the heuristic QUIN algorithm, and give experimental evaluation of the algorithms on a set of artificial domains. QUIN has already been used to induce qualitative control strategies in dynamic domains such as controlling a crane or riding a bicycle (described elsewhere) and can be applied to other domains as a general tool for qualitative system identification.\",\n \"Title: Simple and effective visual models for gene expression cancer diagnostics\\nYear: 2005\\n\\nAbstract: In the paper we show that diagnostic classes in cancer gene expression data sets, which most often include thousands of features (genes), may be effectively separated with simple two-dimensional plots such as scatterplot and radviz graph. The principal innovation proposed in the paper is a method called VizRank, which is able to score and identify the best among possibly millions of candidate projections for visualizations. Compared to recently much applied techniques in the field of cancer genomics that include neural networks, support vector machines and various ensemble-based approaches, VizRank is fast and finds visualization models that can be easily examined and interpreted by domain experts. Our experiments on a number of gene expression data sets show that VizRank was always able to find data visualizations with a small number of (two to seven) genes and excellent class separation. In addition to providing grounds for gene expression cancer diagnosis, VizRank and its visualizations also identify small sets of relevant genes, uncover interesting gene interactions and point to outliers and potential misclassifications in cancer data sets.\",\n \"Title: Learning Predictive Qualitative Models With Pade\\nYear: 2011\\n\\nAbstract: Qualitative models are similar to regression models, except that instead of numerical predictions they provide insight into how a change of a certain input variable affects the output within a context of other inputs. Although people usually reason qualitatively, machine learning has mostly ignored this type of model. We present a new approach to learning qualitative models from numerical data. We describe Pade, a suite of methods for estimating partial derivatives of unknown sampled target functions. We show how to build qualitative models using standard machine learning algorithms by replacing the output variable with signs of computed derivatives.Experiments show that the developed methods are quite accurate, scalable to high number of dimensions and robust with regard to noise.\",\n \"Title: Qualitatively faithful quantitative prediction\\nYear: 2003\\n\\nAbstract: Abstract We describe an approach to machine,learning from numerical data that combines,both qualitative and numerical learning. This approach is carried out in two stages: (1) induction of a qualitative model from numerical examples of the behaviour of a physical system, and (2) induction of a numerical,regression function that both respects the qualitative constraints and fits the training data numerically. We call this approach Q, learning to the identification of a car wheel suspension system—a complex, industrially relevant mechanical system. 2004 Elsevier B.V. All rights reserved. Keywords: Automated model building; System identification; Machine learning; Qualitative reasoning; Learning\",\n \"Title: Pessimistic Heuristics Beat Optimistic Ones in Real-Time Search\\nYear: 2006\\n\\nAbstract: Admissibility is a desired property of heuristic evaluation functions, because when these heuristics are used with complete search methods, such as A* and RBFS, they guarantee that an optimal solution will be found. Since every optimistic heuristic function is admissible, optimistic functions are widely used. We show, however, that with incomplete, real-time search, optimistic functions lose their appeal, and in fact they may hinder the search under quite reasonable conditions. Under these conditions the exact opposite is to be preferred, i.e. pessimistic heuristic functions that never underestimate the difficulty of the problem. We demonstrate that such heuristics behave better than optimistic ones of equal quality on a standard testbed using RTA* search method.\",\n \"Title: Autonomous discovery of abstract concepts by a robot\\nYear: 2011\\n\\nAbstract: In this paper we look at the discovery of abstract concepts by a robot autonomously exploring its environment and learning the laws of the environment. By abstract concepts we mean concepts that are not explicitly observable in the measured data, such as the notions of obstacle, stability or a tool. We consider mechanisms of machine learning that enable the discovery of abstract concepts. Such mechanisms are provided by the logic based approach to machine learning called Inductive Logic Programming (ILP). The feature of predicate invention in ILP is particularly relevant. Examples of actually discovered abstract concepts in experiments are described.\",\n \"Title: Discovery of Genetic Networks Through Abduction and Qualitative Simulation\\nYear: 2007\\n\\nAbstract: GenePath is an automated system for reasoning about genetic networks, wherein a set of genes have various influences on one another and on a biological outcome. It acts on a set of experiments in which genes are knocked-out or overexpressed, and the outcome of interest is evaluated. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on background knowledge and experimental results. Two uses of the system are demonstrated: synthesis of a consistent network from abduced constraints, and qualitative reasoning-based approach that generates a set of networks consistent with the data. In practice, as illustrated by an example on aggregation of a soil amoeba Dictyostelium discoideum, a combination of constraint satisfaction and qualitative reasoning produces a small set of plausible networks.\",\n \"Title: Learning to Fly Simple and Robust\\nYear: 2004\\n\\nAbstract: We report on new experiments with machine learning in the reconstruction of human sub-cognitive skill. The particular problem considered is to generate a clone of a human pilot performing a flying task on a simulated aircraft. The work presented here uses the human behaviour to create constraints for a search process that results in a controller - pilot's clone. Experiments in this paper indicate that this approach, called \\\"indirect controllers\\\", results in pilot clones that are, in comparison with those obtained with traditional \\\"direct controllers\\\", simpler, more robust and easier to understand. An important feature of indirect controllers in this paper is the use of qualitative constraints.\",\n \"Title: Factors Affecting Diminishing Returns For Searching Deeper\\nYear: 2007\\n\\nAbstract: The phenomenon of diminishing returns for additional search effort has been observed by several researchers. We study experimentally additional factors which influence the behaviour of diminishing returns that manifest themselves in go-deep experiments. The results obtained on a large set of more than 40,000 positions from chess grandmaster games using the programs CRAFTY, RYBKA, and SHREDDER show that diminishing returns depend on (a) the values of the positions, (b) the quality of the evaluation function of the program used, and to some extent also on (c) the phase of the game, and the amount of material on the board.\",\n \"Title: Fighting Knowledge Acquisition Bottleneck with Argument Based Machine Learning\\nYear: 2008\\n\\nAbstract: Knowledge elicitation is known to be a difficult task and thus a major bottleneck in building a knowledge base. Machine learning has long ago been proposed as a way to alleviate this problem. Machine learning usually helps the domain expert to uncover some of the more tacit concepts. However, the learned concepts are often hard to understand and hard to extend. A common view is that a combination of a domain expert and machine learning would yield the best results. Recently, argument based machine learning (ABML) has been introduced as a combination of argumentation and machine learning. Through argumentation, ABML enables the expert to articulate his knowledge easily and in a very natural way. ABML was shown to significantly improve the comprehensibility and accuracy of the learned concepts. This makes ABML a most natural tool for constructing a knowledge base. The present paper shows how this is accomplished through a case study of building a knowledge base of an expert system used in a chess tutoring application.\",\n \"Title: Attribute Interactions in Medical Data Analysis\\nYear: 2003\\n\\nAbstract: There is much empirical evidence about the success of naive Bayesian classification (NBC) in medical applications of attribute-based machine learning. NBC assumes conditional independence between attributes. In classification, such classifiers sum up the pieces of class-related evidence from individual attributes, independently of other attributes. The performance, however, deteriorates significantly when the \\\"interactions\\\" between attributes become critical. We propose an approach to handling attribute interactions within the framework of \\\"voting\\\" classifiers, such as NBC. We propose an operational test for detecting interactions in learning data and a procedure that takes the detected interactions into account while learning. This approach induces a structuring of the domain of attributes, it may lead to improved classifier's performance and may provide useful novel information for the domain expert when interpreting the results of learning. We report on its application in data analysis and model construction for the prediction of clinical outcome in hip arthroplasty.\",\n \"Title: Combining learning constraints and numerical regression\\nYear: 2005\\n\\nAbstract: Usual numerical learning methods are primarily concerned with finding a good numerical fit to data and often make predictions that do not correspond to qualitative laws in the domain of modelling or expert intuition. In contrast, the idea of Q2 learning is to induce qualitative constraints from training data, and use the constraints to guide numerical regression. The resulting numerical predictions are consistent with a learned qualitative model which is beneficial in terms of explanation of phenomena in the modelled domain, and can also improve numerical accuracy. This paper proposes a method for combining the learning of qualitative constraints with an arbitrary numerical learner and explores the accuracy and explanation benefits of learning monotonic qualitative constraints in a number of domains. We show that Q2 learning can correct for errors caused by the bias of the learning algorithm and discuss the potentials of similar hierarchical learning schemes.\",\n \"Title: Embodied Concept Discovery Through Qualitative Action Models\\nYear: 2011\\n\\nAbstract: We present a novel approach to embodied learning of qualitative models. We introduce, algorithm STRUDEL that enables an autonomous robot to discover new concepts by performing experiments in its environment. The robot collects data about its actions and its observations of the environment. Prom the obtained data, the robot lean is qualitative descriptive models of the effects that its actions have in the environment. Models are learned using inductive logic programming. We describe two experiments with a humanoid robot Nao in which Nao learns descriptive qualitative models which contain what can be interpreted as simple definitions of the concepts of movability and stability.\",\n \"Title: Information-Based Evaluation Criterion for Classifier's Performance\\nYear: 1991\\n\\nAbstract: In the past few years many systems for learning decision rules from examples were developed. As different systems allow different types of answers when classifying new instances, it is difficult to appropriately evaluate the systems' classification power in comparison with other classification systems or in comparison with human experts. Classification accuracy is usually used as a measure of classification performance. This measure is, however, known to have several defects. A fair evaluation criterion should exclude the influence of the class probabilities which may enable a completely uninformed classifier to trivially achieve high classification accuracy. In this paper a method for evaluating the information score of a classifier's answers is proposed. It excludes the influence of prior probabilities, deals with various types of imperfect or probabilistic answers and can be used also for comparing the performance in different domains.\",\n \"Title: Constructing Intermediate Concepts by Decomposition of Real Functions\\nYear: 1997\\n\\nAbstract: . In learning from examples it is often useful to expand an attribute-vectorrepresentation by intermediate concepts. The usual advantage of such structuring of thelearning problem is that it makes the learning easier and improves the comprehensibilityof induced descriptions. In this paper, we develop a technique for discovering usefulintermediate concepts when both the class and the attributes are real-valued. Thetechnique is based on a decomposition method originally developed for the...\",\n \"Title: Trading Accuracy for Simplicity in Decision Trees\\nYear: 1994\\n\\nAbstract: When communicating concepts, it is often convenient or even necessary to define a concept approximately. A simple, although only approximately accurate concept definition may be more useful than a completely accurate definition which involves a lot of detail. This paper addresses the problem: given a completely accurate, but complex, definition of a concept, simplify the definition, possibly at the expense of accuracy, so that the simplified definition still corresponds to the concept “sufficiently” well. Concepts are represented by decision trees, and the method of simplification is tree pruning. Given a decision tree that accurately specifies a concept, the problem is to find a smallest pruned tree that still represents the concept within some specified accuracy. A pruning algorithm is presented that finds an optimal solution by generating a dense sequence of pruned trees, decreasing in size, such that each tree has the highest accuracy among all the possible pruned trees of the same size. An efficient implementation of the algorithm, based on dynamic programming, is presented and empirically compared with three progressive pruning algorithms using both artificial and real-world data. An interesting empirical finding is that the real-world data generally allow significantly greater simplification at equal loss of accuracy.\",\n \"Title: Multi-agent strategic modeling in a robotic soccer domain\\nYear: 2006\\n\\nAbstract: This paper presents an algorithm for multi-agent strategic modeling (MASM) applied in a robotic soccer domain. It transforms a multi-agent action sequence into a set of strategic action descriptions in a graphical and symbolic form. By using hierarchically ordered domain knowledge, the algorithm is able to generate graphic and symbolic strategic action descriptions together with corresponding rules at different levels of abstraction. The method was evaluated on the RoboCup Soccer Server Internet League data.\",\n \"Title: Elicitation of neurological knowledge with ABML\\nYear: 2011\\n\\nAbstract: The paper describes the process of knowledge elicitation for a neurological decision support system. To alleviate the difficult problem of knowledge elicitation from data and domain experts, we used a recently developed technique called ABML (Argument Based Machine Learning). The paper demonstrates ABML's advantage in combining machine learning and expert knowledge. ABML guides the expert to explain critical special cases which cannot be handled automatically by machine learning. This very efficiently reduces the expert's workload, and combines it with automatically learned knowledge. We developed a decision support system to help the neurologists differentiate between three types of tremors: Parkinsonian, essential, and mixed tremor (co-morbidity). The system is intended to act as a second opinion for the neurologists, and most importantly to help them reduce the number of patients in the \\\"gray area\\\" that require a very costly further examination (DaTSCAN).\",\n \"Title: Microarray data mining with visual programming.\\nYear: 2005\\n\\nAbstract: Visual programming offers an intuitive means of combining known analysis and visualization methods into powerful applications. The system presented here enables users who are not programmers to manage microarray and genomic data flow and to customize their analyses by combining common data analysis tools to fit their needs.http://www.ailab.si/supp/bi-visproghttp://www.ailab.si/supp/bi-visprog.\",\n \"Title: Knowledge base for finite-element mesh design learned by inductive logic programming\\nYear: 1998\\n\\nAbstract: This paper addresses an important application of machine learning (ML) in design. One of the major bottlenecks in the process of engineering analysis by using the finite-element method—a design of the finite-element mesh—was a subject of improvement. Defining an appropriate geometric mesh model that ensures low approximation errors and avoids unnecessary computational overhead is a very difficult and time-consuming task based mainly on the user's experience. A knowledge base for finite-element mesh design has been constructed using the ML techniques. Ten mesh models have been used as a source of training examples. The mesh dataset was probably the first real-world relational dataset and became one of the most widely used training set for experimenting with inductive logic programming (ILP) systems. After several experiments with different ML systems in the last few years, the ILP system CLAUDIEN was chosen to construct the rules for determining the appropriate mesh resolution values. The ILP has been found to be an effective approach to the problem of mesh design. An evaluation of the resulting knowledge base shows that the mesh design patterns are captured well by the induced rules and represent a solid basis for practical application. The aim of this paper is not only to present the real-life ML application to design, but also to describe and discuss a relation of the work being done to the topic of this special issue: the proposed “dimensions” of ML in design.\",\n \"Title: Symbolic and qualitative reconstruction of control skill\\nYear: 1999\\n\\nAbstract: Controlling a complex dynamic system, such as a plane or acrane, usually requires a skilled operator. Such a control skillis typically hard to reconstruct through introspection. Thereforean attractive approach to the reconstruction of control skillinvolves machine learning from operators\\\" control traces, alsoknown as behavioural cloning. In the most common approach tobehavioural cloning, a controller is induced as a direct mappingfrom system states to actions. Unfortunately, such...\",\n \"Title: ABML knowledge refinement loop: a case study\\nYear: 2012\\n\\nAbstract: Argument Based Machine Learning (ABML) was recently demonstrated to offer significant benefits for knowledge elicitation. In knowledge acquisition, ABML is used by a domain expert in the so-called ABML knowledge refinement loop. This draws the expert's attention to the most critical parts of the current knowledge base, and helps the expert to argue about critical concrete cases in terms of the expert's own understanding of such cases. Knowledge elicited through ABML refinement loop is therefore more consistent with expert's knowledge and thus leads to more comprehensible models in comparison with other ways of knowledge acquisition with machine learning from examples. Whereas the ABML learning method has been described elsewhere, in this paper we concentrate on detailed mechanisms of the ABML knowledge refinement loop. We illustrate these mechanisms with examples from a case study in the acquisition of neurological knowledge, and provide quantitative results that demonstrate how the model evolving through the ABML loop becomes increasingly more consistent with the expert's knowledge during the process.\",\n \"Title: Deriving concepts and strategies from chess tablebases\\nYear: 2009\\n\\nAbstract: Complete tablebases, indicating best moves for every position, exist for chess endgames. There is no doubt that tablebases contain a wealth of knowledge, however, mining for this knowledge, manually or automatically, proved as extremely difficult. Recently, we developed an approach that combines specialized minimax search with the argument-based machine learning (ABML) paradigm. In this paper, we put this approach to test in an attempt to elicit human-understandable knowledge from tablebases. Specifically, we semi-automatically synthesize knowledge from the KBNK tablebase for teaching the difficult king, bishop, and knight versus the lone king endgame.\",\n \"Title: Machine learning applied to quality management-A study in ship repair domain\\nYear: 2007\\n\\nAbstract: The awareness about the importance of knowledge within the quality management community is increasing. For example, the Malcolm Baldrige Criteria for Performance Excellence recently included knowledge management into one of its categories. However, the emphasis in research related to knowledge management is mostly on knowledge creation and dissemination, and not knowledge formalisation process. On the other hand, identifying the expert knowledge and experience as crucial for the output quality, especially in dynamic industries with high share of incomplete and unreliable information such as ship repair, this paper argues how important it is to have such knowledge formalised. The paper demonstrates by example of delivery time estimate how for that purpose the deep quality concept (DQC)-a novel knowledge-focused quality management framework, and machine learning methodology could be effectively used. In the concluding part of the paper, the accuracy of the obtained prediction models is analysed, and the chosen model is discussed. The research indicates that standardisation of problem domain notions and expertly designed databases with possible interface to machine learning algorithms need to be considered as an integral part of any quality management system in the future, in addition to conventional quality management concepts.\",\n \"Title: Function decomposition in machine learning\\nYear: 2001\\n\\nAbstract: To solve a complex problem, one of the effective general approaches is to decompose it into smaller, less complex and more\\n manageable subproblems. In machine learning, this principle is a foundation for structured induction [44]: instead of learning\\n a single complex classification rule from examples, define a concept hierarchy and learn rules for each of the (sub)concepts.\\n Shapiro [44] used structured induction for the classification of a fairly complex chess endgame and demonstrated that the\\n complexity and comprehensiveness (“brain-compatibility”) of the obtained solution was superior to the unstructured one. Shapiro\\n was helped by a chess master to structure his problem domain. Typically, applications of structured induction involve a manual\\n development of the hierarchy and a manual selection and classification of examples to induce the subconcept classification\\n rules; usually this is a tiresome process that requires an active availability of a domain expert over long periods of time.\\n Therefore, it would be very desirable to automate the problem decomposition task.\",\n \"Title: Machine learning for survival analysis: a case study on recurrence of prostate cancer\\nYear: 2000\\n\\nAbstract: Machine learning techniques have recently received considerable attention, especially when used for the construction of prediction models from data. Despite their potential advantages over standard statistical methods, like their ability to model non-linear relationships and construct symbolic and interpretable models, their applications to survival analysis are at best rare, primarily because of the difficulty to appropriately handle censored data. In this paper we propose a schema that enables the use of classification methods — including machine learning classifiers — for survival analysis. To appropriately consider the follow-up time and censoring, we propose a technique that, for the patients for which the event did not occur and have short follow-up times, estimates their probability of event and assigns them a distribution of outcome accordingly. Since most machine learning techniques do not deal with outcome distributions, the schema is implemented using weighted examples. To show the utility of the proposed technique, we investigate a particular problem of building prognostic models for prostate cancer recurrence, where the sole prediction of the probability of event (and not its probability dependency on time) is of interest. A case study on preoperative and postoperative prostate cancer recurrence prediction shows that by incorporating this weighting technique the machine learning tools stand beside modern statistical methods and may, by inducing symbolic recurrence models, provide further insight to relationships within the modeled data.\",\n \"Title: Is real-valued minimax pathological?\\nYear: 2006\\n\\nAbstract: Deeper searches in game-playing programs relying on the minimax principle generally produce better results. Theoretical analyses, however, suggest that in many cases minimaxing amplifies the noise introduced by the heuristic function used to evaluate the leaves of the game tree, leading to what is known as pathological behavior, where deeper searches produce worse results. In most minimax models analyzed in previous research, positions' true values and sometimes also heuristic values were only losses and wins. In contrast to this, a model is proposed in this paper that uses real numbers for both true and heuristic values. This model did not behave pathologically in the experiments performed. The mechanism that causes deeper searches to produce better evaluations is explained. A comparison with chess is made, indicating that the model realistically reflects position evaluations in chess-playing programs. Conditions under which the pathology might appear in a real-value model are also examined. The essential difference between our real-value model and the common two-value model, which causes the pathology in the two-value model, is identified. Most previous research reports that the pathology tends to disappear when there are dependences between the values of sibling nodes in a game tree. In this paper, another explanation is presented which indicates that in the two-value models the error of the heuristic evaluation was not modeled realistically.\",\n \"Title: Computer Analysis Of World Chess Champions\\nYear: 2006\\n\\nAbstract: Who is the best chess player of all time? Chess players are often interested in this question that has never been answered authoritatively, because it requires a comparison between chess players of different eras who never met across the board. In this contribution, we attempt to make such a comparison. It is based on the evaluation of the games played by the World Chess Champions in their championship matches. The evaluation is performed by the chess-playing program CRAFTY. For this purpose we slightly adapted CRAFTY. Our analysis takes into account the differences in players' styles to compensate the fact that calm positional players in their typical games have less chance to commit gross tactical errors than aggressive tactical players. Therefore, we designed a method to assess the difficulty of positions. Some of the results of this computer analysis might be quite surprising. Overall, the results can be nicely interpreted by a chess expert.\",\n \"Title: Proving correctness of strategies in the AL1 assertional language\\nYear: 1978\\n\\nAbstract: Combinatorial programming, program correctness, computer chess\",\n \"Title: Application of argument based machine learning to law\\nYear: 2005\\n\\nAbstract: In this paper we discuss the application of a new machine learning approach - argumentation based machine learning - to the legal domain. Argumentation based machine learning is particularly suited to law as it makes use of the justifications of decisions to guide its learning. Importantly, where a large number of decided cases are available, it provides a way of identifying which need to be considered, so that only decisions which will have an influence are examined.\",\n \"Title: Testing the significance of attribute interactions\\nYear: 2004\\n\\nAbstract: Attribute interactions are the irreducible dependencies between attributes. Interactions underlie feature relevance and selection, the structure of joint probability and classification models: if and only if the attributes interact, they should be connected. While the issue of 2-way interactions, especially of those between an attribute and the label, has already been addressed, we introduce an operational definition of a generalized n-way interaction by highlighting two models: the reductionistic part-to-whole approximation, where the model of the whole is reconstructed from models of the parts, and the holistic reference model, where the whole is modelled directly. An interaction is deemed significant if these two models are significantly different. In this paper, we propose the Kirkwood superposition approximation for constructing part-to-whole approximations. To model data, we do not assume a particular structure of interactions, but instead construct the model by testing for the presence of interactions. The resulting map of significant interactions is a graphical model learned from the data. We confirm that the P-values computed with the assumption of the asymptotic X2 distribution closely match those obtained with the boot-strap.\",\n \"Title: A Program For Playing Tarok\\nYear: 2003\\n\\nAbstract: A program for playing the three-player tarok card game is presented and the complexity of the game is analyzed. To deal with the unknown distributions of other players' cards, the program uses a sampling method that accomplishes hierarchical clustering to select representative sets of cards from a host of, randomly generated sets. A, game tree is searched with the alpha-beta algorithm using several common enhancements and an equivalence transposition table, which group the positions by strategic similarity instead of storing single positions.\",\n \"Title: Applications of inductive logic programming\\nYear: 1994\\n\\nAbstract: Techniques of machine learning have been successfully applied to various problems [1, 12]. Most of these applications rely on attribute-based learning, exemplified by the induction of decision trees as in the program C4.5 [20]. Broadly speaking, attribute-based learning also includes such approaches to learning as neural networks and nearest neighbor techniques. The advantages of attribute-based learning are: relative simplicity, efficiency, and existence of effective techniques for handling noisy data. However, attribute-based learning is limited to non-relational descriptions of objects in the sense that the learned descriptions do not specify relations among the objects' parts. Attribute-based learning thus has two strong limitations:the background knowledge can be expressed in rather limited form, andthe lack of relations makes the concept description language inappropriate for some domains.\",\n \"Title: Abductive Inference of Genetic Networks\\nYear: 2001\\n\\nAbstract: GenePath is an automated system for reasoning on genetic networks, wherein a set of genes have various influences on one another and on a biological outcome. It acts on a set of experiments in which genes are knocked out or overexpressed, and the outcome of interest is evaluated. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on prior knowledge and experimental results. Two uses of the system are demonstrated: synthesis of a consistent network from abduced constraints, and qualitative reasoning-based approach that generates a set of networks consistent with the data. In practice, illustrated by an example using Dictyostelium aggregation, a combination of constraint satisfaction and qualitative reasoning produces a small set of plausible networks.\",\n \"Title: Argument Based Machine Learning from Examples and Text\\nYear: 2009\\n\\nAbstract: We introduce a novel approach to cross-media learning based on argument based machine learning (ABML). ABML is a recent method that combines argumentation and machine learning from examples, and its main idea is to use arguments for some of the learning examples. Arguments are usually provided by a domain expert. In this paper, we present an alternative approach, where arguments used in ABML are automatically extracted from text with a technique for relation extraction. We demonstrate and evaluate the approach through a case study of learning to classify animals by using arguments automatically extracted from Wikipedia.\",\n \"Title: Argument based machine learning in a medical domain\\nYear: 2006\\n\\nAbstract: Argument Based Machine Learning (ABML) is a new approach to machine learning in which the learning examples can be accompanied by arguments. The arguments for specific examples are a special form of expert's knowledge which the expert uses to substantiate the class value for the chosen example. Možina et al. developed the ABCN2 algorithm-an extension of the well known rule learning algorithm CN2-that can use argumented examples in the learning process. In this work we present an application of ABCN2 in the medical domain which deals with severe bacterial infections in geriatric population. The elderly population, people over 65 years of age, is rapidly growing as well as the costs of treating this population. In our study, we compare ABCN2 to CN2 and show that using arguments we improve the characteristics of the model. We also report the results that C4.5, Naïve Bayes and Logistic Regression achieve in this domain.\",\n \"Title: Computer Analysis of Chess Champions\\nYear: 2006\\n\\nAbstract: Who is the best chess player of all time? Chess players are often interested in this question that has never been answered\\n authoritatively, because it requires a comparison between chess players of different eras who never met across the board.\\n In this contribution, we attempt to make such a comparison. It is based on the evaluation of the games played by the World\\n Chess Champions in their championship matches. The evaluation is performed by the chess-playing program Crafty. For this purpose we slightly adapted Crafty. Our analysis takes into account the differences in players’ styles to compensate the fact that calm positional players in\\n their typical games have less chance to commit gross tactical errors than aggressive tactical players. Therefore, we designed\\n a method to assess the difficulty of positions. Some of the results of this computer analysis might be quite surprising. Overall,\\n the results can be nicely interpreted by a chess expert.\",\n \"Title: Why minimax works: an alternative explanation\\nYear: 2005\\n\\nAbstract: In game-playing programs relying on the minimax principle, deeper searches generally produce better evaluations. Theoretical analyses, however, suggest that in many cases minimaxing amplifies the noise introduced by the heuristic function used to evaluate the leaves of the game tree, leading to what is known as pathological behavior, where deeper searches produce worse evaluations. In most of the previous research, positions were evaluated as losses or wins. Dependence between the values of positions close to each other was identified as the property of realistic game trees that eliminates the pathology and explains why minimax is successful in practice. In this paper we present an alternative explanation that does not rely on value dependence. We show that if real numbers are used for position values, position values tend to be further apart at lower levels of the game tree, which leads to a larger proportion of more extreme positions, where error is less probable. Decreased probability of error in searches to greater depths is sufficient to eliminate the pathology and no additional properties of game trees are required.\",\n \"Title: Elicitation of neurological knowledge with argument-based machine learning.\\nYear: 2013\\n\\nAbstract: The paper describes the use of expert's knowledge in practice and the efficiency of a recently developed technique called argument-based machine learning (ABML) in the knowledge elicitation process. We are developing a neurological decision support system to help the neurologists differentiate between three types of tremors: Parkinsonian, essential, and mixed tremor (comorbidity). The system is intended to act as a second opinion for the neurologists, and most importantly to help them reduce the number of patients in the \\\"gray area\\\" that require a very costly further examination (DaTSCAN). We strive to elicit comprehensible and medically meaningful knowledge in such a way that it does not come at the cost of diagnostic accuracy.To alleviate the difficult problem of knowledge elicitation from data and domain experts, we used ABML. ABML guides the expert to explain critical special cases which cannot be handled automatically by machine learning. This very efficiently reduces the expert's workload, and combines expert's knowledge with learning data. 122 patients were enrolled into the study.The classification accuracy of the final model was 91%. Equally important, the initial and the final models were also evaluated for their comprehensibility by the neurologists. All 13 rules of the final model were deemed as appropriate to be able to support its decisions with good explanations.The paper demonstrates ABML's advantage in combining machine learning and expert knowledge. The accuracy of the system is very high with respect to the current state-of-the-art in clinical practice, and the system's knowledge base is assessed to be very consistent from a medical point of view. This opens up the possibility to use the system also as a teaching tool.\",\n \"Title: Quantifying and Visualizing Attribute Interactions\\nYear: 2003\\n\\nAbstract: Interactions are patterns between several attributes in data that cannot be\\ninferred from any subset of these attributes. While mutual information is a\\nwell-established approach to evaluating the interactions between two\\nattributes, we surveyed its generalizations as to quantify interactions between\\nseveral attributes. We have chosen McGill's interaction information, which has\\nbeen independently rediscovered a number of times under various names in\\nvarious disciplines, because of its many intuitively appealing properties. We\\napply interaction information to visually present the most important\\ninteractions of the data. Visualization of interactions has provided insight\\ninto the structure of data on a number of domains, identifying redundant\\nattributes and opportunities for constructing new features, discovering\\nunexpected regularities in data, and have helped during construction of\\npredictive models; we illustrate the methods on numerous examples. A machine\\nlearning method that disregards interactions may get caught in two traps:\\nmyopia is caused by learning algorithms assuming independence in spite of\\ninteractions, whereas fragmentation arises from assuming an interaction in\\nspite of independence.\",\n \"Title: Refining Complete Hypotheses in ILP\\nYear: 1999\\n\\nAbstract: Most ILP systems employ the covering algorithm whereby hypotheses are constructed iteratively clause by clause. Typically the covering algorithm is greedy in the sense that each iteration adds the best clause according to some local evaluation criterion. Some typical problems of the covering algorithm are: unnecessarily long hypotheses, difficulties in handling recursion, difficulties in learning multiple predicates. This paper investigates a non-covering approach to ILP, implemented as a Prolog program called HYPER, whose goals were: use intensional background knowledge, handle recursion well, and enable multi-predicate learning. Experimental results in this paper may appear surprising in the view of the very high combinatorial complexity of the search space associated with the non-covering approach.\",\n \"Title: Problem Decomposition for Behavioural Cloning\\nYear: 2000\\n\\nAbstract: In behavioural cloning of the human operator's skill, a controller is usually induced directly as a classifier from system's states into actions. Experience shows that this often results in brittle controllers. In this paper we explore a decomposition of the cloning problem into two learning problems: the learning of operator's control trajectories and the learning of the system's dynamics separately. We analyse advantages of such indirect controllers. We give characterization of the learner's error that is plausible explanation of why this decomposition approach has empirically proved to be usually superior to direct cloning.\",\n \"Title: Machine learning in artificial intelligence\\nYear: 1993\\n\\nAbstract: Among several forms of learning, learning concepts from examples is the most common and best understood. In this paper some approaches to learning concepts from examples are reviewed. In particular those approaches that are currently most important with respect to practical applications (learning decision trees and if-then rules), or likely to become very important in the near future (Inductive Logic Programming as a form of relational learning) are discussed.\",\n \"Title: Machine Learning by Function Decomposition\\nYear: 1997\\n\\nAbstract: We present a new machine learning method that, given a set of training examples, induces a denition of the target concept in terms of a hierarchy of intermediate concepts and their denitions. This eectively decomposes the problem into smaller, less complex problems. The method is inspired by the Boolean func- tion decomposition approach to the design of digital circuits. To cope with high time complexity of nding an optimal decomposi- tion, we propose a suboptimal heuristic al- gorithm. The method, implemented in pro- gram HINT (HIerarchy Induction Tool), is ex- perimentally evaluated using a set of arti- cial and real-world learning problems. It is shown that the method performs well both in terms of classication accuracy and discovery of meaningful concept hierarchies.\",\n \"Title: Search versus Knowledge: An Empirical Study of Minimax on KRK\\nYear: 2003\\n\\nAbstract: This article presents the results of an empirical experiment designed to gain insight into what is the effect of the minimax algorithm on the evaluation function. The experiment's simulations were performed upon the KRK chess endgame. Our results show that dependencies between evaluations of sibling nodes in a game tree and an abundance of possibilities to commit blunders present in the KRK endgame are not sufficient to explain the success of the minimax principle in practical game-playing as was previously believed. The article shows that minimax in combination with a noisy evaluation function introduces a bias into the backed-up evaluations and argues that this bias is what masked the effectiveness of the minimax. in previous studies.\",\n \"Title: VizRank: Data Visualization Guided by Machine Learning\\nYear: 2006\\n\\nAbstract: Data visualization plays a crucial role in identifying interesting patterns in exploratory data analysis. Its use is, however, made difficult by the large number of possible data projections showing different attribute subsets that must be evaluated by the data analyst. In this paper, we introduce a method called VizRank, which is applied on classified data to automatically select the most useful data projections. VizRank can be used with any visualization method that maps attribute values to points in a two-dimensional visualization space. It assesses possible data projections and ranks them by their ability to visually discriminate between classes. The quality of class separation is estimated by computing the predictive accuracy of k-nearest neighbor classifier on the data set consisting of x and y positions of the projected data points and their class information. The paper introduces the method and presents experimental results which show that VizRank's ranking of projections highly agrees with subjective rankings by data analysts. The practical use of VizRank is also demonstrated by an application in the field of functional genomics.\",\n \"Title: Using machine learning techniques to interpret results from discrete event simulation\\nYear: 1994\\n\\nAbstract: This paper describes an approach to the interpretation of discrete event simulation results using machine learning techniques. The results of two simulators were processed as machine learning problems. Interpretation obtained by the regression tree learning system Retis was intuitive but obviously expressed in a complicated way. To enable a more powerful knowledge representation, Inductive Logic Programming (ILP) system Markus was used, that also highlighted some attribute combinations. These attribute combinations were used as new attributes in further experiments with Retis and Assistant. Some interesting regularities were thereby automatically discovered.\",\n \"Title: Learning by discovering concept hierarchies\\nYear: 1999\\n\\nAbstract: We present a new machine learning method that, given a set of training examples, induces a definition of the target concept in terms of a hierarchy of intermediate concepts and their definitions. This effectively decomposes the problem into smaller, less complex problems. The method is inspired by the Boolean function decomposition approach to the design of switching circuits. To cope with high time complexity of finding an optimal decomposition, we propose a suboptimal heuristic algorithm. The method, implemented in program HINT(Hierarchy INduction Tool), is experimentally evaluated using a set of artificial and real-world learning problems. In particular, the evaluation addresses the generalization property of decomposition and its capability to discover meaningful hierarchies. The experiments show that HINT performs well in both respects. (C) 1999 Elsevier Science B.V. All rights reserved.\",\n \"Title: On estimating probabilities in tree pruning\\nYear: 1991\\n\\nAbstract: In this paper we introduce a new method for decision tree pruning, based on the minimisation of the expected classification error method by Niblett and Bratko. The original Niblett-Bratko pruning algorithm uses Laplace probability estimates. Here we introduce a new, more general Bayesian approach to estimating probabilities which we call m-probability-estimation. By varying a parameter m in this method, tree pruning can be adjusted to particular properties of the learning domain, such as level of noise. The resulting pruning method improves on the original Niblett-Bratko pruning in the following respects: apriori probabilities can be incorporated into error estimation, several trees pruned to various degrees can be generated, and the degree of pruning is not affected by the number of classes. These improvements are supported by experimental findings. m-probability-estimation also enables the combination of learning data obtained from various sources.\",\n \"Title: Why is rule learning optimistic and how to correct it\\nYear: 2006\\n\\nAbstract: In their search through a huge space of possible hypotheses, rule induction algorithms compare estimations of qualities of a large number of rules to find the one that appears to be best. This mechanism can easily find random patterns in the data which will – even though the estimating method itself may be unbiased (such as relative frequency) – have optimistically high quality estimates. It is generally believed that the problem, which eventually leads to overfitting, can be alleviated by using m-estimate of probability. We show that this can only partially mend the problem, and propose a novel solution to making the common rule evaluation functions account for multiple comparisons in the search. Experiments on artificial data sets and data sets from the UCI repository show a large improvement in accuracy of probability predictions and also a decent gain in AUC of the constructed models.\",\n \"Title: Discovery of abstract concepts by a robot\\nYear: 2010\\n\\nAbstract: This paper reviews experiments with an approach to discovery through robot’s experimentation in its environment. In addition\\n to discovering laws that enable predictions, we are particularly interested in the mechanisms that enable the discovery of\\n abstract concepts that are not explicitly observable in the measured data, such as the notions of a tool or stability. The\\n approach is based on the use of Inductive Logic Programming. Examples of actually discovered abstract concepts in the experiments\\n include the concepts of a movable object, an obstacle and a tool.\",\n \"Title: Skill reconstruction as induction of LQ controllers with subgoals\\nYear: 1997\\n\\nAbstract: Controlling a complex dynamic system, such as a plane or a crane, usually requires a skilled operator. Such a control skill is typically hard to reconstruct through introspection. Therefore an attractive approach to the reconstruction of control skill involves machine learning from operators' control traces, also known as behavioural cloning. In the most common approach to behavioural cloning, a controller is induced in the form of a rule set or a decision or regression tree that maps system states to actions. Unfortunately, induced controllers usually suffer from lack of robustness and lack typical elements of human control strategies, such as subgoals and substages of the control plan. In this paper we present a new approach to behavioural cloning which involves the induction of a model of the controlled system and enables the identification of subgoals that the operator is pursuing at various stages of the execution trace. The underlying formal basis for the present approach to behavioural cloning is the theory of LQ controllers. Experimental results show that this approach greatly improves the robustness of the induced controllers and also offers a new way of understanding the operator's subcognitive skill.\",\n \"Title: Search versus knowledge revisited again\\nYear: 2006\\n\\nAbstract: The questions focusing on diminishing returns for additional search effort have been a burning issue in computer chess. Despite a lot of research in this field, there are still some open questions, e.g., what happens at search depths beyond 12 plies, and what is the effect of the program's knowledge on diminishing returns? The paper presents an experiment that attempts to answer these questions. The results (a) confirm that diminishing returns in chess exist, and more importantly (b) show that the amount of knowledge a program has influences when diminishing returns will start to manifest themselves.\",\n \"Title: When is it better not to look ahead?\\nYear: 2010\\n\\nAbstract: In situations where one needs to make a sequence of decisions, it is often believed that looking ahead will help produce better decisions. However, it was shown 30 years ago that there are ''pathological'' situations in which looking ahead is counterproductive. Two long-standing open questions are (a) what combinations of factors have the biggest influence on whether lookahead pathology occurs, and (b) whether it occurs in real-world decision-making. This paper includes simulation results for several synthetic game-tree models, and experimental results for three well-known board games: two chess endgames, kalah (with some modifications to facilitate experimentation), and the 8-puzzle. The simulations show the interplay between lookahead pathology and several factors that affect it; and the experiments confirm the trends predicted by the simulation models. The experiments also show that lookahead pathology is more common than has been thought: all three games contain situations where it occurs.\",\n \"Title: A Dataset Decomposition Approach to Data Mining and Machine Discovery\\nYear: 1997\\n\\nAbstract: We present a novel data mining approach basedon decomposition. In order to analyze a givendataset, the method decomposes it to a hierarchyof smaller and less complex datasets that canbe analyzed independently. The method is experimentallyevaluated on a real-world housingloans allocation dataset, showing that the decompositioncan (1) discover meaningful intermediateconcepts, (2) decompose a relatively complexdataset to datasets that are easy to analyze andcomprehend, and (3) derive a...\",\n \"Title: Learning long-term chess strategies from databases\\nYear: 2006\\n\\nAbstract: We propose an approach to the learning of long-term plans for playing chess endgames. We assume that a computer-generated database for an endgame is available, such as the king and rook vs. king, or king and queen vs. king and rook endgame. For each position in the endgame, the database gives the \\\"value\\\" of the position in terms of the minimum number of moves needed by the stronger side to win given that both sides play optimally. We propose a method for automatically dividing the endgame into stages characterised by different objectives of play. For each stage of such a game plan, a stage-specific evaluation function is induced, to be used by minimax search when playing the endgame. We aim at learning playing strategies that give good insight into the principles of playing specific endgames. Games played by these strategies should resemble human expert's play in achieving goals and subgoals reliably, but not necessarily as quickly as possible.\",\n \"Title: Dynamic system simulation with qualitative differential equations\\nYear: 1992\\n\\nAbstract: Qualitative differential equations (QDE) are a popular formalism for modelling dynamic systems qualitatively. This paper briefly introduces the basic concepts of this approach, including types of constraints used in QDE and the QSIM simulation algorithm. It also discusses the relation of QSIM to other approaches to qualitative modelling, such as confluences and Qualitative Physics Theory, and the advantages and limitations of QSIM. Selected annotated bibliography is also given.\",\n \"Title: Web-Enabled Knowledge-Based Analysis of Genetic Data\\nYear: 2001\\n\\nAbstract: We present a web-based implementation of GenePath, an intelligent assistant tool for data analysis in functional genomics. GenePath considers mutant data and uses expert-defined patterns to find gene-to-gene or gene-to-outcome relations. It presents the results of analysis as genetic networks, wherein a set of genes has various influence on one another and on a biological outcome. In the paper, we particularly focus on its web-based interface and explanation mechanisms.\",\n \"Title: Independent-valued minimax: Pathological or beneficial?\\nYear: 2012\\n\\nAbstract: Minimax search, which is used by most game-playing programs, is considered pathological when deeper searches produce worse evaluations than shallower ones. This phenomenon was first observed in theoretical analyses under seemingly reasonable conditions. It was most commonly explained by the lack of dependence between nearby positions in the analyses: if nearby positions have similar values, as is typically the case in real games, the pathology no longer occurs. In this paper, we show that the pathology can be eliminated even without position-value dependence, by assigning enough different values to the positions and modeling the heuristic error as normally distributed noise that is independent of the depth in the game tree. This leads to the conclusion that minimax is less prone to the pathology than was previously thought and indicates the importance of the number of different position values.\",\n \"Title: An Experiment in Robot Discovery with ILP\\nYear: 2008\\n\\nAbstract: We describe an experiment in the application of ILP to autonomous discovery in a robotic domain. An autonomous robot is performing experiments in its world, collecting data and formulating predictive theories about this world. In particular, we are interested in the robot's \\\"gaining insights\\\" through predicate invention. In the first experimental scenario in a pushing blocks domain, the robot discovers the notion of objects' movability. The second scenario is about discovering the notion of obstacle. We describe experiments with a simulated robot, as well as an experiment with a real robot when robot's observations contain noise.\",\n \"Title: Improving vehicle aeroacoustics using machine learning\\nYear: 2012\\n\\nAbstract: This paper presents a new approach to improving the overall aeroacoustic comfort of a vehicle, an important feature of vehicle design. The traditional improvement process is extended to benefit extensively from machine learning, information retrieval and information extraction technologies to assist the wind tunnel engineers with difficult tasks. The paper first describes the general approach and then focuses on providing a detailed description of the most important task of assessing the degree of discomfort for a human caused by wind noise in a vehicle, when the noise spectrum is known. For this purpose a novel approach of learning linear regression models that are consistent with expert's domain knowledge is presented. The results of the end user evaluation of the entire system are also presented to reflect the strengths of this approach.\",\n \"Title: GenePath: a system for automated construction of genetic networks from mutant data.\\nYear: 2003\\n\\nAbstract: Motivation: Genetic networks are often used in the analysis of biological phenomena. In classical genetics, they are constructed manually from experimental data on mutants. The field lacks formalism to guide such analysis, and accounting for all the data becomes complicated when large amounts of data are considered. Results: We have developed GenePath, an intelligent assistant that automates the analysis of genetic data. GenePath employs expert-defined patterns to uncover gene relations from the data, and uses these relations as constraints in the search for a plausible genetic network. GenePath formalizes genetic data analysis, facilitates the consideration of all the available data in a consistent manner, and the examination of the large number of possible consequences of planned experiments. It also provides an explanation mechanism that traces every finding to the pertinent data.\",\n \"Title: Learning qualitative models from numerical data: extended abstract\\nYear: 2013\\n\\nAbstract: Qualitative models are predictive models that describe how changes in values of input variables affect the output variable in qualitative terms, e.g. increasing or decreasing. We describe Padé, a new method for qualitative learning which estimates partial derivatives of the target function from training data and uses them to induce qualitative models of the target function. We formulated three methods for computation of derivatives, all based on using linear regression on local neighbourhoods. The methods were empirically tested on artificial and real-world data. We also provide a case study which shows how the developed methods can be used in practice.\",\n \"Title: Learning Positional Features for Annotating Chess Games: A Case Study\\nYear: 2008\\n\\nAbstract: By developing an intelligent computer system that will provide commentary of chess moves in a comprehensible, user-friendly, and instructive way, we are trying to use the power demonstrated by the current chess engines for tutoring chess and for annotating chess games. In this paper, we point out certain differences between the computer programs which are specialized for playing chess and our program which is aimed at providing quality commentary. Through a case study, we present an application of argument-based machine learning, which combines the techniques of machine learning and expert knowledge, to the construction of more complex positional features, in order to provide our annotating system with an ability to comment on various positional intricacies of positions in the game of chess.\",\n \"Title: Likelihood based classification in Bayesian networks\\nYear: 2007\\n\\nAbstract: Learning directed probabilistic networks from data and using them for classification purposes is a well known problem. Many learning algorithms have been shown to be successful for various kinds of learning scenarios. Basically they all generate a single network from data, which is then used for classification purposes and possible domain understanding. In this paper we propose a simple method for inferring a model consisting of several Bayesian networks, each one representing data of one class. The data is divided into class subsets and from each subset a separate Bayesian network is learnt. Classification is done using prior and posterior probability distribution information in all networks. We thoroughly tested the proposed method on synthetic data and several repository datasets and compared it to other machine learning methods, to prove its effectiveness. We argue that with smaller modifications, the method can be used for learning from censored survival domains.\",\n \"Title: Improving Numerical Prediction with Qualitative Constraints\\nYear: 2003\\n\\nAbstract: The usual numerical learning methods, that are primarily concerned with finding a good numerical fit to the data, often make predictions that do not correspond to the qualitative mechanisms in the domain of modelling or a domain expert's intuition. Consistency of numerical predictions with a given qualitative model is helpful when a numerical model is used for explanation of phenomena in the modelled domain, but can also considerably improve numerical accuracy. In this paper we present a novel approach to numerical machine learning called Qfilter. Qfilter is a numerical regression method that can take into account qualitative background knowledge to give qualitatively faithful numerical prediction. The results on a set of domains including population dynamics show considerable prediction accuracy improvements compared to the usual numerical learners. As qualitative domain knowledge is often available in practice, Qfilter's ability to exploit such knowledge should be beneficial in many applications.\",\n \"Title: A knowledge base for finite element mesh design\\nYear: 1994\\n\\nAbstract: The finite element method (FEM) is the most successful numerical method, that is used extensively by engineers to analyse stresses and deformations in physical structures. These structures should be represented as a finite element mesh. Defining an appropriate geometric mesh model that ensures low approximation errors and avoids unnecessary computational overheads is a very difficult and time consuming task. It is the major bottleneck in the FEM analysis process. The inductive logic programming system GOLEM has been employed to construct the rules for deciding about the appropriate mesh resolution. Five cylindrical mesh models have been used as a source of training examples. The evaluation of the resulting knowledge base shows that conditions in the domain are well represented by the rules, which specify the required number of the finite elements on the edges of the structures to be analysed using FEM. A comparison between the results obtained by this knowledge base and conventional mesh generation techniques confirms that the application of inductive logic programming is an effective approach to solving the problem of mesh design.\",\n \"Title: Dex Methodology: Three Decades Of Qualitative Multi-Attribute Modeling\\nYear: 2013\\n\\nAbstract: DEX is a qualitative multi-attribute decision modeling methodology that integrates multi-criteria decision modeling with rule-based expert systems. The method was conceived in 1979. Since, it has been continuously developed and implemented in a wide range of computer programs that have been applied in hundreds of practical decision-making studies. Here we present its main methodological concepts, contributions to the theory and practice of decision support, and outline a history of its development and evolution.\",\n \"Title: VizRank: finding informative data projections in functional genomics by machine learning.\\nYear: 2005\\n\\nAbstract: VizRank is a tool that finds interesting two-dimensional projections of class-labeled data. When applied to multi-dimensional functional genomics datasets, VizRank can systematically find relevant biological patterns.http://www.ailab.si/supp/bi-vizrankhttp://www.ailab.si/supp/bi-vizrank.\",\n \"Title: GenePath: a system for inference of genetic networks and proposal of genetic experiments.\\nYear: 2003\\n\\nAbstract: A genetic network is a formalism that is often used in biology to represent causalities and reason about biological phenomena related to genetic regulation. We present GenePath, a computer-based system that supports the inference of genetic networks from a set of genetic experiments. Implemented in Prolog, GenePath uses abductive inference to elucidate network constraints based on background knowledge and experimental results. Additionally, it can propose genetic experiments that may further refine the discovered network and establish relations between genes that could not be related based on the original experimental data. We illustrate GenePath's approach and utility on analysis of data on aggregation and sporulation of the soil amoeba Dictyostelium discoideum.\",\n \"Title: Q2 Learning and Its Application to Car Modelling\\nYear: 2006\\n\\nAbstract: In this paper we describe an application of Q(2) learning, a recently developed approach to machine learning in numerical domains (Suc et al., 2003, 2004) to the automated modelling of a complex, industrially relevant mechanical system - a four wheel suspension and steering system of a car. In this experiment, first a qualitative model of this dynamic system was induced from data, and then this model was reified into a quantitative model. The induced qualitative models enable explanation of relations among the variables in the system and, when reified into quantitative models, enable accurate numerical prediction. Furthermore, the qualitative guidance of the quantitative modelling process leads to predictions that are significantly more accurate than those obtained by state-of-the-art numerical learning methods.\",\n \"Title: Qualitative Simulation with Answer Set Programming.\\nYear: 2014\\n\\nAbstract: Qualitative Simulation (QSIM) reasons about the behaviour of dynamic physical systems as they evolve over time. The system is represented by a coarse qualitative model rather than precise numerical models. However, for large complex domains, such as robotics for Urban Search and Rescue, existing QSIM implementations are inefficient. ASPQSIM is a novel formulation of the QSIM algorithm in Answer Set Programming that takes advantage of the similarities between qualitative simulation and constraint satisfaction problems. ASPQSIM is compared against an existing QSIM implementation on a variety of domains that demonstrate ASPQSIM provides a significant improvement in efficiency especially on complex domains, and producing simulations in domains that are not solvable by the procedural implementation.\",\n \"Title: Feature transformation by function decomposition\\nYear: 1998\\n\\nAbstract: The function decomposition described can identify subsets of existing features and discover nongiven functions that map these subsets to a new feature, also, it can organize the existing and new features into a hierarchy. The authors demonstrate their Hierarchy Induction Tool (HINT) system on a housing loan-allocation application. Methods for switching circuit design often implicitly deal with feature transformation. Such methods construct a circuit to implement a given or partially given tabulated Boolean function. The authors' function-decomposition method can discover and construct a hierarchy of new features that one can add to the original dataset or transform into a hierarchy of less complex datasets. The method allows the decomposition to deal with nominal-feature (that is, not necessarily binary) functions\",\n \"Title: Qualitative Planning of Object Pushing by a Robot.\\nYear: 2015\\n\\nAbstract: Pushing is often used by robots as a simple way to manipulate the environment and has in the past been well studied from kinematic and numerical perspective. The paper proposes a qualitative approach to pushing convex polygonal objects by a simple wheeled robot through a single point contact. We show that by using qualitative reasoning, pushing dynamics can be described in concise and intuitive manner, that is still sufficient to control the robot to successfully manipulate objects. Using the QUIN program on numerical data collected by our robot while experimentally pushing objects of various shapes, we induce a model of pushing. This model is then used by our planning algorithm to push objects of previously unused shapes to given goal configurations. The produced trajectories are compared to smooth geometric solutions. Results show the correctness of our qualitative model of pushing and efficiency of the planning algorithm.\",\n \"Title: Extracting qualitative relations from categorical data.\\nYear: 2016\\n\\nAbstract: Qualitative modeling is traditionally concerned with the abstraction of numerical data. In numerical domains, partial derivatives describe the relation between the independent and dependent variable; qualitatively, they tell us the trend of the dependent variable. In this paper, we address the problem of extracting qualitative relations in categorical domains. We generalize the notion of partial derivative by defining the probabilistic discrete qualitative partial derivative (PDQ PD). PDQ PD is a qualitative relation between the target class c and the discrete attribute; the derivative corresponds to ordering the attribute's values, a i , by P ( c | a i ) in a local neighborhood of the reference point, respecting the ceteris paribus principle. We present an algorithm for computation of PDQ PD from labeled attribute-based training data. Machine learning algorithms can then be used to induce models that explain the influence of the attribute's values on the target class in different subspaces of the attribute space.\",\n \"Title: Reactive Motion Planning with Qualitative Constraints.\\nYear: 2017\\n\\nAbstract: Qualitative modeling tends to be closer to human type of reasoning than traditional numerical modeling and proved to be very useful in certain branches of cognitive robotics. However, due to the lack of precise numerical relations, planning with qualitative models has been achieved to a limited extent. Typically, it is bound to predicting possible future behaviors of the system, and demands additional exploration of numerical relations, before constructed plans can be executed. In this paper we show how qualitative models can be interpreted in terms of reactive planning, to produce executable actions without the need for additional numerical learning. We demonstrate our method on two classical motion planning problems – pursuing and obstacle avoidance, and a complex problem of pushing objects.\",\n \"Title: Feasibility of spirography features for objective assessment of motor function in Parkinson's disease.\\nYear: 2017\\n\\nAbstract: •A method for self-monitoring the motor function in Parkinson's disease is presented.•Slowness of movement (bradykinesia) is typically associated with under-medication.•Involuntary movements (dyskinesia) can be the result of over-medication.•A machine learning model that detects bradykinesia and dyskinesia is proposed.•The model's visual explanatory power is evaluated.\",\n \"Title: Using Heuristic-Search Based Engines for Estimating Human Skill at Chess.\\nYear: 2011\\n\\nAbstract: Establishing heuristic-search based chess programs as appropriate tools for estimating human skill levels at chess may seem impossible due to the following issues: the programs' evaluations and decisions tend to change with the depth of search and with the program used. In this research, we provide an analysis of the differences between heuristic-search based programs in estimating chess skill. We used four different chess programs to perform analyses of large data sets of recorded human decisions, and obtained very similar rankings of skill-based performances of selected chess players using any of these programs at various levels of search. A conclusion is that, given two chess players, all the programs unanimously rank one player to be clearly stronger than the other, or all the programs assess their strengths to be similar. We also repeated our earlier analysis with the program CRAFTY of the human World Chess Champions with currently one of the strongest chess programs, RYBKA 3(2), and obtained qualitatively very similar results as with CRAFTY. This speaks in favour of computer heuristic search being adequate for estimating skill levels of chess players, despite the above stated issues.\",\n \"Title: Alphazero - What'S Missing?\\nYear: 2018\\n\\nAbstract: In December 2017, the game playing program AlphaZero was reported to have learned in less than 24 hours to play each of the games of chess, Go and shogi better than any human, and better than any other existing specialised computer program for these games. This was achieved just by self-play, without access to any knowledge of these games other than the rules of the game. In this paper we consider some limitations to this spectacular success. The program was trained in well-defined and relatively small domains (admittedly with enormous combinatorial complexity) compared to many real world problems, and it was possible to generate large amounts of learning data through simulated games which is typically not possible in real life domains. When it comes to understanding the games played by AlphaZero, the program's inability to explain its games and the knowledge acquired in human-understandable terms is a serious limitation.\",\n \"Title: Identifying typical approaches and errors in Prolog programming with argument-based machine learning.\\nYear: 2018\\n\\nAbstract: •Abstract-syntax-tree (AST) patterns as attributes for classifying Prolog programs.•Identification of AST patterns for detecting errors and programming approaches.•An argument-based algorithm for learning rules suitable for tutoring.•Evaluation of extracted patterns and rules on 42 Prolog exercises.\",\n \"Title: A Machine Learning System For Controlling A Rescue Robot\\nYear: 2017\\n\\nAbstract: Many rescue robots are reconfigurable, having subtracks (or flippers) that can be adjusted to help the robot traverse different types of terrain. Knowing how to adjust them requires skill on the part of the operator. If the robot is intended to run autonomously, the control system must have an understanding of how the flippers affect the robot's interaction with the ground. We describe a system that first learns the effects of a robot's actions and then uses this knowledge to plan how to reconfigure the robot's tracks so that it can overcome different types of obstacles. The system is a hybrid of qualitative symbolic learning and reinforcement learning.\",\n \"Title: Extreme value correction: a method for correcting optimistic estimations in rule learning\\nYear: 2019\\n\\nAbstract: Machine learning algorithms rely on their ability to evaluate the constructed hypotheses for choosing the optimal hypothesis during learning and assessing the quality of the model afterwards. Since these estimates, in particular the former ones, are based on the training data from which the hypotheses themselves were constructed, they are usually optimistic. The paper shows three different solutions; two for the artificial boundary cases with the smallest and the largest optimism and a general correction procedure called extreme value correction (EVC) based on extreme value distribution. We demonstrate the application of the technique to rule learning, specifically to estimating classification accuracy of a single rule, and evaluate it on an artificial data set and on a number of UCI data sets. We observed that the correction successfully improved the accuracy estimates. We also describe an approach for combining rules into a linear global classifier and show that using EVC estimates leads to more accurate classifiers.\",\n \"Title: Learning from noisy data using a non-covering ILP algorithm\\nYear: 2010\\n\\nAbstract: In this paper we describe the non-covering inductive logic programming program HYPER/N, concentrating mainly on noise handling as well as some other mechanisms that improve learning. We perform some experiments with HYPER/N on synthetic weather data with artificially added noise, and on real weather data to learn to predict the movement of rain from radar rain images and synoptic data.\",\n \"Title: Using Machine Learning to Understand Operator's Skill\\nYear: 2002\\n\\nAbstract: Controlling complex dynamic systems requires skills that operators often cannot completely describe, but can demonstrate. This paper describes research into the understanding of such tacit control skills. Understanding tacit skills has practical motivation in respect of communicating skill to other operators, operator training, and also mechanising and optimising human skill. This paper is concerned with approaches whereby, using techniques of machine learning, controllers that emulate the human operators are generated from examples of control traces. This process is also called \\\"behavioural cloning\\\". The paper gives a review of ML-based approaches to behavioural cloning, representative experiments, and an assessment of the results. Some recent work is presented with particular emphasis on understanding human tacit skill, and generating explanation of how it works. This includes the extraction of the operator's subconscious sub-goals and the use of qualitative control strategies. We argue for qualitative problem representations and decomposition of the machine learning problem involved.\",\n \"Title: Multiobjective discovery of human-like driving strategies\\nYear: 2017\\n\\nAbstract: Human driving models aim at producing human-like driving strategies by mimicking the behavior of drivers. Drivers optimize several objectives when traveling along a route, such as the traveling time and the fuel consumption. However, these objectives are not taken into account when building human driving models. To overcome this shortcoming, we designed a two-level Multiobjective Optimization algorithm for discovering Human-like Driving Strategies (MOHDS) that combines the human driving models with the optimization of the traveling time and the fuel consumption. Consequently, MOHDS enables to simultaneously mimic human driving behavior and optimize relevant driving objectives. MOHDS was tested on a two-lane rural route and compared to the existing approaches for human driving modeling. The results show that, unlike the existing approaches, MOHDS finds the driving strategies with various tradeoffs between the objectives.\",\n \"Title: Rewrite Rules for Debugging Student Programs in Programming Tutors.\\nYear: 2018\\n\\nAbstract: Data-driven intelligent tutoring systems learn to provide feedback based on past student behavior, reducing the effort required for their development. A major obstacle to applying data-driven methods in the programming domain is the lack of meaningful observable actions for describing the students problem-solving process. We propose rewrite rules as a language-independent formalization of programm...\",\n \"Title: Influence of Search Depth on Position Evaluation.\\nYear: 2017\\n\\nAbstract: By using a well-known chess program and a large data set of chess positions from real games we demonstrate empirically that with increasing search depth backed-up evaluations of won positions tend to increase, while backed-up evaluations of lost positions tend to decrease. We show three implications of this phenomenon in practice and in the theory of computer game playing. First, we show that heuristic evaluations obtained by searching to different search depths are not directly comparable. Second, we show that fewer decision changes with deeper search are a direct consequence of this property of heuristic evaluation functions. Third, we demonstrate that knowing this property may be used to develop a method for detecting fortresses in chess, which is an unsolved task in computer chess.\",\n \"Title: Learning Explainable Control Strategies Demonstrated on the Pole-and-Cart System.\\nYear: 2019\\n\\nAbstract: The classical problem of balancing an inverted pendulum is commonly used to evaluate control learning techniques. Traditional learning methods aim to improve the performance of the learned controller, often disregarding comprehensibility of the learned control policies. Recently, Explainable AI (XAI) has become of great interest in the areas where humans can benefit from insights discovered by AI, or need to check whether AI's decisions make sense. Learning qualitative models allows formulation of learned hypotheses in a comprehensible way, closer to human intuition than traditional numerical learning. In this paper, we use a qualitative approach to learning control strategies, which we demonstrate on the problem of balancing an inverted pendulum. We use qualitative induction to learn a qualitative model from experimentally collected numerical traces, and qualitative simulation to search for possible qualitative control strategies, which are tested through reactive execution. Successful behaviors provide a clear explanation of the learned control strategy.\",\n \"Title: Identification And Conceptualization Of Procedural Chunks In Chess\\nYear: 2021\\n\\nAbstract: When it comes to cognitive architecture and human information processing, chunks are one of the best known and most recognized constructs. Nevertheless, the nature of chunks is still very elusive, especially when it comes to chunks in procedural knowledge. This study deals with basic features of procedural information processing and examines the manifestation of chunks in procedural knowledge. The participants' task was to reconstruct sequences of chess moves. Chess was chosen as an experimental domain, because of its complexity, well-defined rules and standardized measure of chess player strength. From the results we conclude that short-term memory capacity is determined by the combination of the size and amount of procedural chunks recalled to the short-term memory. We have shown that on average, participants with more specialized knowledge operated faster and with larger chunks of procedural information than participants with less specialized knowledge. We have shown that in procedural information processing, the level of expertise and the sorting order of the retrieved information are important factors that influence the amount of procedural chunks retained in the short-term memory. Therefore, the capacity of short-term memory in complex situations cannot be expressed as a simple concept. (C) 2021 Elsevier B.V. All rights reserved.\",\n \"Title: Are pre-service teachers disinclined to utilise embodied humanoid social robots in the classroom?\\nYear: 2021\\n\\nAbstract: Teachers' readiness for technology integration depends also on their beliefs about the contribution of technology to teaching and learning, which influence their motivation for its adoption. Initial pre-service teacher education is critical in reducing the attitude-behaviour divide supporting technology acceptability, acceptance and use. Acceptance of interaction between human and robot is more complicated than human-computer interaction acceptance. Social robots are radical innovations, harder for potential users to accept in human social spaces than are incremental innovations. In 2019, a survey using a convenience sample of 121 first-year students was conducted to examine pre-service teachers' beliefs about social robot educational technology. It examined the following factors derived from the Unified Theory of Acceptance and Use of Technology adopted for social robots in education: Perceived social dimension, Intention to use, Perceived usability, Anxiety. Based on our findings, it seems there is a critical disjunction between researchers' efforts to equip social robots with human manners and social intelligence and participants' rejection of this technology precisely because it mimics being human. Further, we report that ICT familiarity as assessed using PISA's Information Communication Technology-ICT familiarity factors is related to robot acceptability. These findings need further examination to inform educational robotics design and Human-Robot Interaction research and teacher education and training. Practitioners notes What is already known about this topic In the age of robotic technology, teachers face requirements to prepare students for work and life with social robots. Social robots are tested for classroom integration. Teachers' readiness to implement robot lessons depends on their beliefs about social robotic technology's contribution to teaching. Research and development in the field of social robotics still tend to focus more frequently on technology applications rather than pedagogical issues and advancing teaching and learning. What this paper adds Participants refuse to accept the idea of social robot-based instruction. The identified belief pattern is based mainly on the perceived social dimension, intention to use, perceived usability and anxiety. Participants critically perceive the robot's social dimension. Some of PISA's ICT familiarity factors are related to robots acceptability factors. Implication for policy and/or practice The policy and practice need to address how social robots could be integrated into current teaching and learning practices and more importantly how could robotic technology facilitate innovative pedagogical models for effective and efficient learning. The introduction of social robots should follow instructional design requirements and not merely technological advancement. Teacher initial education has to provide social robotic learning environments for pre-service teachers to experiment and design.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":104,"string":"104"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13369,"string":"13,369"}}},{"rowIdx":13370,"cells":{"question_id":{"kind":"string","value":"Shahid Hussain"},"question":{"kind":"string","value":"Generate an abstract for the title \"Three-Phase Methodology to Manage the COVID-19 Information for Classification of Mental Illness\" using the following items: 1. Social media\n2. Misinformation\n3. COVID-19 impact on mental illness\n4. Two-step methodology\n5. Unsupervised learning algorithm"},"answer":{"kind":"string","value":"In the COVID-19 era, the use of social media platforms has significantly increased leading to misinformation being produced whose management is quite necessary for the domain experts, such as the Reddit social platform where people disseminate extensive information about their health issues using relevant posts and comments. The management of misinformation about COVID-19 impact on mental illness could be quite beneficial for the domain experts. In this regard, we proposed a two-step methodology which could aid domain experts to manage and group the posts and comments information with respect to COVID-19 impact on mental illness. First, we extract the information of well-known mental illnesses (such as depression, anxiety, OCD and PTSD) from the Raddit platform. Second, we leverage the capabilities of unsupervised learning algorithms and text categorisation approach to manage the information. We also proposed the evaluation model to assess the efficacy of the proposed method according to expert opinion. The experimental results indicate the efficacy of the proposed method. Moreover, we observed fuzzy c-means as an outperformed learner (with ARI = 0.76) as compared to K-means (ARI = 0.70) and Agglomerative (ARI = 0.69)."},"correct_answer":{"kind":"string","value":"In the COVID-19 era, the use of social media platforms has significantly increased leading to misinformation being produced whose management is quite necessary for the domain experts, such as the Reddit social platform where people disseminate extensive information about their health issues using relevant posts and comments. The management of misinformation about COVID-19 impact on mental illness could be quite beneficial for the domain experts. In this regard, we proposed a two-step methodology which could aid domain experts to manage and group the posts and comments information with respect to COVID-19 impact on mental illness. First, we extract the information of well-known mental illnesses (such as depression, anxiety, OCD and PTSD) from the Raddit platform. Second, we leverage the capabilities of unsupervised learning algorithms and text categorisation approach to manage the information. We also proposed the evaluation model to assess the efficacy of the proposed method according to expert opinion. The experimental results indicate the efficacy of the proposed method. Moreover, we observed fuzzy c-means as an outperformed learner (with ARI = 0.76) as compared to K-means (ARI = 0.70) and Agglomerative (ARI = 0.69)."},"documents":{"kind":"list like","value":["Title: Sequential Optimization Of Paths In Directed Graphs Relative To Different Cost Functions\nYear: 2011\n\nAbstract: This paper is devoted to the consideration of an algorithm for sequential optimization of paths in directed graphs relative to different cost functions. The considered algorithm is based on an extension of dynamic programming which allows to represent the initial set of paths and the set of optimal paths after each application of optimization procedure in the form of a directed acyclic graph.","Title: Sequential optimization of matrix chain multiplication relative to different cost functions\nYear: 2011\n\nAbstract: In this paper, we present a methodology to optimize matrix chain multiplication sequentially relative to different cost functions such as total number of scalar multiplications, communication overhead in a multiprocessor environment, etc. For n matrices our optimization procedure requires O(n3) arithmetic operations per one cost function. This work is done in the framework of a dynamic programming extension that allows sequential optimization relative to different criteria.","Title: Effect of Cadence Regulation on Muscle Activation Patterns During Robot-Assisted Gait: A Dynamic Simulation Study.\nYear: 2013\n\nAbstract: Cadence or stride frequency is an important parameter being controlled in gait training of neurologically impaired subjects. The aim of this study was to examine the effects of cadence variation on muscle activation patterns during robot-assisted unimpaired gait using dynamic simulations. A 2-D musculoskeletal model of human gait was developed considering eight major muscle groups along with an existing ground contact force model. A 2-D model of a robotic orthosis was also developed that provides actuation to the hip, knee, and ankle joints in the sagittal plane to guide subject's limbs on reference trajectories. A custom inverse dynamics algorithm was used along with a quadratic minimization algorithm to obtain a feasible set of muscle activation patterns. Predicted patterns of muscle activations during slow, natural, and fast cadence were compared and the mean muscle activations were found to be increasing with an increase in cadence. The proposed dynamic simulation provides important insight into the muscle activation variations with change in cadence during robot-assisted gait and provides the basis for investigating the influence of cadence regulation on neuromuscular parameters of interest during robot-assisted gait.","Title: Optimization And Analysis Of Decision Trees And Rules: Dynamic Programming Approach\nYear: 2013\n\nAbstract: This paper is devoted to the consideration of software system Dagger created in KAUST. This system is based on extensions of dynamic programming. It allows sequential optimization of decision trees and rules relative to different cost functions, derivation of relationships between two cost functions (in particular, between number of misclassifications and depth of decision trees), and between cost and uncertainty of decision trees. We describe features of Dagger and consider examples of this system's work on decision tables from UCI Machine Learning Repository. We also use Dagger to compare 16 different greedy algorithms for decision tree construction.","Title: Sequential optimization of binary search trees for multiple cost functions\nYear: 2011\n\nAbstract: In this paper, we present a methodology to model the optimal binary search tree problem as a directed acyclic graph to extract all possible optimal solutions. We provide a mechanism to find optimal binary search trees relative to different types of cost functions, sequentially. We prove that for a set of n keys our optimization procedure makes O(n3) arithmetic operations per cost function such as weighted depth or average weighted depth.","Title: Automatic Vehicle Checking Agent (VCA)\nYear: 2011\n\nAbstract: A definition of intelligence is given in terms of performance that can be quantitatively measured. In this study, we have presented a conceptual model of Intelligent Agent System for Automatic Vehicle Checking Agent (VCA). To achieve this goal, we have introduced several kinds of agents that exhibit intelligent features. These are the Management agent, internal agent, External Agent, Watcher agent and Report agent. Metrics and measurements are suggested for evaluating the performance of Automatic Vehicle Checking Agent (VCA). Calibrate data and test facilities are suggested to facilitate the development of intelligent systems.","Title: Adaptive impedance control of a robotic orthosis for gait rehabilitation.\nYear: 2013\n\nAbstract: Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis w...","Title: Control of a robotic orthosis for gait rehabilitation\nYear: 2013\n\nAbstract: Robot assisted gait training may help in producing rapid improvements in functional gait parameters. This paper presents new experimental results with an intrinsically compliant robotic gait training orthosis. The newly developed robotic orthosis has 6 degrees of freedom (DOFs). A trajectory tracking controller based on the boundary layer augmented sliding control (BASMC) law was implemented to guide the subject's limbs on physiological gait trajectories. The compliance of the robotic orthosis sagittal plane hip and knee joints was also controlled, independently of the trajectory tracking control. The robotic orthosis and the control scheme were evaluated on three neurologically intact subjects walking on a treadmill. A maximum trajectory tracking error of 10^o was recorded at the hip and knee sagittal plane joints. The results showed that subjects can walk in the robotic orthosis with comfort and the BASMC law was able to guide the subject's limbs on reference physiological trajectories.","Title: Totally Optimal Decision Trees for Monotone Boolean Functions with at Most Five Variables.\nYear: 2013\n\nAbstract: In this paper, we present the empirical results for relationships between time (depth) and space (number of nodes) complexity of decision trees computing monotone Boolean functions, with at most five variables. We use Dagger (a tool for optimization of decision trees and decision rules) to conduct experiments. We show that, for each monotone Boolean function with at most five variables, there exists a totally optimal decision tree which is optimal with respect to both depth and number of nodes.","Title: Learning hereditary and reductive prolog programs from entailment\nYear: 2009\n\nAbstract: In this paper we study exact learning of Prolog programs from entailment and present an algorithm to learn two rich classes of Prolog programs namely hereditary and reductive Prolog programs. These classes contain standard Prolog programs with and without recursion like append, merge, split, delete, member, prefix, suffix, length, add, etc. Additionally our algorithm learns the hereditary Prolog programs in polynomial time.","Title: A Step towards Software Corrective Maintenance Using RCM model\nYear: 2009\n\nAbstract: From the preliminary stage of software engineering, selection of appropriate\nenforcement of standards remained a challenge for stakeholders during entire\ncycle of software development, but it can lead to reduce the efforts desired\nfor software maintenance phase. Corrective maintenance is the reactive\nmodification of a software product performed after delivery to correct\ndiscovered faults. Studies conducted by different researchers reveal that\napproximately 50 to 75 percent of the effort is spent on maintenance, out of\nwhich about 17 to 21 percent is exercised on corrective maintenance. In this\npaper, authors proposed a RCM (Reduce Corrective Maintenance) model which\nrepresents the implementation process of number of checklists to guide the\nstakeholders of all phases of software development. These check lists will be\nfilled by corresponding stake holder of all phases before its start. More\nprecise usage of the check list in relevant phase ensures successful\nenforcement of analysis, design, coding and testing standards for reducing\nerrors in operation stage. Moreover authors represent the step by step\nintegration of checklists in software development life cycle through RCM model.","Title: The Proper Role of Agents in Future Resilient Smart Grids.\nYear: 2014\n\nAbstract: Smart Grids are in focus of several international R&D past and present efforts since at least a decade. Smart Grids is a well-known metaphor for future power grids. However, the meaning, or semantics of the concept has, naturally, changed due to increased understanding of the inherent complexities of the subject matter. The driving forces behind the efforts on Smart Grids include: Demands of integrating new energy sources such as Distributed Energy Resources (DER) and Renewable Energy Resources (RES) in a massive way into generation, transmission and distribution of future energy systems. Establishment of a de-regulated customer oriented energy markets, including new types of energy based service markets. Design and implementation of resilient and trustworthy services coordinating and monitoring use-case dependent sets of stakeholders during operations. The transition from today's mostly hierarchical power grids towards tomorrow's Smart Grids poses several challenges to be properly addressed and harnessed. We argue that proper use of agent technologies is a key technology towards this end. Furthermore, we argue that design and implementation of Smart Grids have to be supported by Configurable Experiment Platforms to carter for the under specifications of such systems. Resilience of systems has several aspects. We focus on resilience related to different kinds of cyber attacks and self-healing.","Title: Dynamic modeling of pneumatic muscles using modified fuzzy inference mechanism\nYear: 2009\n\nAbstract: Pneumatic muscle actuators (PMA), owing to their obvious advantages over conventional linear actuators and pneumatic cylinders, have been recently used in the medical and industrial robotic applications. However, their potential has not been fully exploited due to their highly nonlinear and time dependent behavior. An attempt is being made in the proposed work to accurately predict the uncertain and ambiguous characteristics of PMA. It was revealed from a scrupulous review of the previous work that conventional tools such as analytical and numerical methods can model a nonlinear system but the time dependent behavior cannot be accurately modeled. In the present research, Artificial Intelligence (AI) based techniques such as Neural Network (NN) and Fuzzy Inference System (FIS) have been used and their results are analyzed. It was found that FIS based on Takagi-Sugeno-Kang inference mechanism provides better accuracy and can model the time dependency of PMA. However, to achieve higher accuracy from the Fuzzy model, its parameters are required to be optimized. Three different approaches, namely, gradient descent method (GD), genetic algorithms (GA) and Modified Genetic Algorithm (MGA) have been used to identify the fuzzy parameters. Results clearly illustrate the improved prediction performance of the MGA based fuzzy inference system. Compared to the previous research in dynamic modeling of PMA, the proposed fuzzy inference system is found to provide better prediction accuracy.","Title: Relationships between depth and number of misclassifications for decision trees\nYear: 2011\n\nAbstract: This paper describes a new tool for the study of relationships between depth and number of misclassifications for decision trees. In addition to the algorithm the paper also presents the results of experiments with three datasets from UCI Machine Learning Repository [3].","Title: Improvement in RUP Project Management via Service Monitoring: Best Practice of SOA\nYear: 2010\n\nAbstract: Management of project planning, monitoring, scheduling, estimation and risk\nmanagement are critical issues faced by a project manager during development\nlife cycle of software. In RUP, project management is considered as core\ndiscipline whose activities are carried in all phases during development of\nsoftware products. On other side service monitoring is considered as best\npractice of SOA which leads to availability, auditing, debugging and tracing\nprocess. In this paper, authors define a strategy to incorporate the service\nmonitoring of SOA into RUP to improve the artifacts of project management\nactivities. Moreover, the authors define the rules to implement the features of\nservice monitoring, which help the project manager to carry on activities in\nwell define manner. Proposed frame work is implemented on RB (Resuming Bank)\napplication and obtained improved results on PM (Project Management) work.","Title: Smart Home Services Enabled by Service Level Agreements\nYear: 2012\n\nAbstract: The challenge for the future Smart Grids is to improve the energy efficiency and enable groups of stakeholders to offer services to customers. An intelligent agent-based ICT infrastructure supplementing SCADA systems is required to support such perspectives of power grids. This paper focus on describing a novel approach, using Service Level Agreements (SLAs) as a tool, for improving coordination between high-level Smart Grid business requirements and low level infrastructure affordances. Monitoring of SLAs and trustworthy data management requires setting up and monitoring clusters of SLAs coordinating sets of relevant stakeholders. We argue that coordinating services with infrastructures using SLA, as a coordination mechanism is a promising approach towards sustainable Smart Grid solutions. A case study of agent-based comfort monitoring and control in Smart homes illustrates our approach and related tools.","Title: Mapping of SOA and RUP: DOA as Case Study\nYear: 2010\n\nAbstract: SOA (Service Oriented Architecture) is a new trend towards increasing the\nprofit margins in an organization due to incorporating business services to\nbusiness practices. Rational Unified Process (RUP) is a unified method planning\nform for large business applications that provides a language for describing\nmethod content and processes. The well defined mapping of SOA and RUP leads to\nsuccessful completion of RUP software projects to provide services to their\nusers. DOA (Digital Office Assistant) is a multi user SOA type application that\nprovides appropriate viewer for each user to assist him through services. In\nthis paper authors proposed the mapping strategy of SOA with RUP by considering\nDOA as case study.","Title: Relationships between Average Depth and Number of Misclassifications for Decision Trees\nYear: 2014\n\nAbstract: This paper presents a new tool for the study of relationships between the total path length or the average depth and the number of misclassifications for decision trees. In addition to algorithm, the paper also presents the results of experiments with datasets from UCI ML Repository [9] and datasets representing Boolean functions with 10 variables.","Title: Mapping The Best Practices of XP and Project Management: Well defined approach for Project Manager\nYear: 2010\n\nAbstract: Software engineering is one of the most recent additions in various\ndisciplines of system engineering. It has emerged as a key obedience of system\nengineering in a quick succession of time. Various Software Engineering\napproaches are followed in order to produce comprehensive software solutions of\naffordable cost with reasonable delivery timeframe with less uncertainty. All\nthese objectives are only satisfied when project's status is properly monitored\nand controlled; eXtreme Programming (XP) uses the best practices of AGILE\nmethodology and helps in development of small size software very sharply. In\nthis paper, authors proposed that via XP, high quality software with less\nuncertainty and under estimated cost can be developed due to proper monitoring\nand controlling of project. Moreover, authors give guidelines that how\nactivities of project management can be embedded into development life cycle of\nXP to enhance the quality of software products and reduce the uncertainty.","Title: Diagnosis of constant faults in iteration-free circuits over monotone basis.\nYear: 2014\n\nAbstract: We show that for each iteration-free combinatorial circuit S over a basis B containing only monotone Boolean functions with at most five variables, there exists a decision tree for diagnosis of constant faults on inputs of gates with depth at most 7 L ( S ) where L ( S ) is the number of gates in S .","Title: Diagnosis of constant faults in read-once contact networks over finite bases.\nYear: 2015\n\nAbstract: We study the depth of decision trees for diagnosis of constant 0 and 1 faults in read-once contact networks over finite bases containing only indecomposable networks. For each basis, we obtain a linear upper bound on the minimum depth of decision trees depending on the number of edges in the networks. For bases containing networks with at most 10 edges we find coefficients for linear bounds which are close to sharp.","Title: Total Path Length and Number of Terminal Nodes for Decision Trees.\nYear: 2014\n\nAbstract: This paper presents a new tool for study of relationships between total path length (average depth) and number of terminal nodes for decision trees. These relationships are important from the point of view of optimization of decision trees. In this particular case of total path length and number of terminal nodes, the relationships between these two cost functions are closely related with space-time trade-off. In addition to algorithm to compute the relationships, the paper also presents results of experiments with datasets from UCI ML Repository1. These experiments show how two cost functions behave for a given decision table and the resulting plots show the Pareto frontier or Pareto set of optimal points. Furthermore, in some cases this Pareto frontier is a singleton showing the total optimality of decision trees for the given decision table.","Title: SLA conceptual framework for coordinating and monitoring information flow in Smart Grid\nYear: 2014\n\nAbstract: The EU challenges for the future energy systems will change the scene of the energy systems in Europe. A transition from centralized controlled power network to customer oriented Smart Grid operating in distributed and deregulated energy market poses several regulatory, organizational and technical challenges. In such a market scenarios, multiple stakeholders provide services to produce and deliver energy. Due to the inclusion of new stakeholders at multiple levels there is a lack of purposeful monitoring based on pre-negotiated SLAs. Hence, there exists a gap to actively monitor KPIs values among all negotiated SLAs (Service Level Agreements). This paper addresses SLA based active monitoring of information flow. The proposed SLA framework provides monitoring based on negotiated KPIs in an automated and trustworthy way to coordinate information flow. In the end a use case is presented to validate the SLA framework.","Title: Multilayer communication network architecture for wind power farm\nYear: 2014\n\nAbstract: Wind is a sustainable renewable energy source, which has recently gained high popularity among the renewable energy sources. The high maintenance and repair cost of wind turbine needs real-time monitoring and control through networks. Network communication infrastructures play important roles for the real-time monitoring and control of wind power farms because these farms are located at remote and harsh environment sites. This paper proposes multilayer communication network architecture for monitoring and controlling of wind power farms which consists of wind power farm layer, local control center layer, regional control center layer, central control center layer and neighbor control center layer. Based on the logical node concept of IEC 61400-25 standard, wind turbine is modeled and simulated by four different information including analogue measurements, status information, protection and control information, and meteorological mast information through OPNET modular. The performance of the proposed network architecture is evaluated in terms of link bandwidth and latency.","Title: Greedy heuristics for minimization of number of terminal nodes in decision trees\nYear: 2014\n\nAbstract: This paper describes, in detail, several greedy heuristics for construction of decision trees. We study the number of terminal nodes of decision trees, which is closely related with the cardinality of the set of rules corresponding to the tree. We compare these heuristics empirically for two different types of datasets (datasets acquired from UCI ML Repository and randomly generated data) as well as compare with the optimal results obtained using dynamic programming method.","Title: Robust Nonlinear Control of an Intrinsically Compliant Robotic Gait Training Orthosis\nYear: 2013\n\nAbstract: Robot-assisted gait therapy is an emerging rehabilitation practice. This paper presents new experimental results with an intrinsically compliant robotic gait training orthosis and a trajectory tracking controller. The intrinsically compliant robotic orthosis has six degrees of freedom. Sagittal plane hip and knee joints were powered by the actuation of pneumatic muscle actuators in opposing pair configuration. The orthosis has passive hip abduction/adduction joint and passive mechanisms to allow vertical and lateral translations of the trunk. A passive foot lifter having a spring mechanism was used to ensure sufficient dorsiflexion during swing phase. A trajectory tracking controller based on a chattering-free robust variable structure control law was implemented in joint space to guide the subject's limbs on physiological gait trajectories. The performance of the robotic orthosis was evaluated during two gait training modes, namely, “trajectory tracking mode with maximum compliance” and “trajectory tracking mode with minimum compliance.” The experimental evaluations were carried out with ten neurologically intact subjects. The results show that the robotic orthosis is able to perform the gait training task during the two gait training modes. All the subjects tend to deviate from the reference joint angle trajectories with an increase in robotic compliance as the subjects have more freedom to voluntarily drive the robotic orthosis.","Title: Service level agreement: Coordination and monitoring of actors in Smart Grid\nYear: 2012\n\nAbstract: Smooth and reliable operation of the future Smart Grid requires addressing coordination and interoperability issues. In Smart Grid, the coordination of new actors and monitoring of new business processes, such as Active Demand and Electric Vehicles is non-trivial. These new actors and related business processes change the landscape of power grid from traditional passive Demand Side Management of loads to active customers connected in Active Distribution Grid. Smart Grid operations require monitoring and coordination between high-level business requirements and low-level infrastructure affordances. To support such perspectives of the power grid an additional ICT infrastructure supplementing traditional SCADA systems is required. We argue that to enable and validate end-to-end interoperable solutions a new tool is required. In this paper we introduce Service Level Agreement as one such a tool, supporting design and implementation of well-coordinated interoperable information flows and ensuring shared agreed-upon situation awareness among stakeholders. Finally we illustrate our approach in Smart Grid Electric Vehicle systems.","Title: Multicriteria Design Optimization of a Parallel Ankle Rehabilitation Robot: Fuzzy Dominated Sorting Evolutionary Algorithm Approach.\nYear: 2016\n\nAbstract: Parallel robots, owing to their increased stiffness, accuracy, and compactness, are preferred over their serial counterparts in applications involving higher torques and precision such as robot-assisted physical therapy. However, their design is complex and calls for obtaining a tradeoff between several conflicting objectives such as the minimization of actuator forces versus the maximization of workspace while maintaining a close to unity condition number, etc. While evolutionary algorithms have been proposed in the literature for simultaneous optimization of many objectives, they have been found to be inefficient in dealing with a large number of objectives. We propose a fuzzy logic-based sorting approach in this paper which effectively replaces the concept of nondominated sorting and provides a better discrimination between solutions and clear termination logic. The proposed sorting algorithm has been evaluated against the existing nondominated sorting genetic algorithm II in the pretext of design optimization of a parallel ankle rehabilitation robot. The proposed fuzzy-based approach is able to provide a better discrimination among solutions and, thereby an improved parallel ankle robot design.","Title: Three-Stage Design Analysis and Multicriteria Optimization of a Parallel Ankle Rehabilitation Robot Using Genetic Algorithm\nYear: 2015\n\nAbstract: This paper describes the design analysis and optimization of a novel 3-degrees of freedom (DOF) wearable parallel robot developed for ankle rehabilitation treatments. To address the challenges arising from the use of a parallel mechanism, flexible actuators, and the constraints imposed by the ankle rehabilitation treatment, a complete robot design analysis is performed. Three design stages of the ...","Title: Effects of Geographical, Socio-cultural and Temporal distances on communication in Global Software Development during Requirements Change Management A Pilot Study\nYear: 2015\n\nAbstract: Trend of software development is changing rapidly most of the software development organizations are trying to globalize their activities throughout the world. This trend leads towards a phenomenon called Global Software Development (GSD). The main reason behind the software globalization is its various benefits. Besides these benefits, software organizations are facing various challenges. One of these challenges is communication which is considered a big challenge in GSD and it becomes more complicated during the Requirements Change Management (RCM) process due to three factors, they are Geographical, Socio-cultural and Temporal distances. This paper presents a framework which shows the effect of these factors on communication during RCM process in GSD. Communication is the core function of collaboration which allows information to be exchanged between the team members. A pilot study has been conducted in three GSD organizations. A quantitative research method has been used to collect data. The findings from the survey data show that these three factors have a strong negative impact on communication process in GSD.","Title: Performance Evaluation of Ensemble Methods For Software Fault Prediction: An Experiment.\nYear: 2015\n\nAbstract: In object-oriented software development, a plethora of studies have been carried out to present the application of machine learning algorithms for fault prediction. Furthermore, it has been empirically validated that an ensemble method can improve classification performance as compared to a single classifier. But, due to the inherent differences among machine learning and data mining approaches, the classification performance of ensemble methods will be varied. In this study, we investigated and evaluated the performance of different ensemble methods with itself and base-level classifiers, in predicting the faults proneness classes. Subsequently, we used three ensemble methods AdaboostM1, Vote and StackingC with five base-level classifiers namely Naivebayes, Logistic, J48, VotedPerceptron and SMO in Weka tool. In order to evaluate the performance of ensemble methods, we retrieved twelve datasets of open source projects from PROMISE repository. In this experiment, we used k-fold (k=10) cross-validation and ROC analysis for validation. Besides, we used recall, precision, accuracy, F-value measures to evaluate the performance of ensemble methods and base-level Classifiers. Finally, we observed significant performance improvement of applying ensemble methods as compared to its base-level classifier, and among ensemble methods we observed StackingC outperformed other selected ensemble methods for software fault prediction.","Title: Impedance Control of an Intrinsically Compliant Parallel Ankle Rehabilitation Robot.\nYear: 2016\n\nAbstract: Robot-aided physical therapy should encourage subject's voluntary participation to achieve rapid motor function recovery. In order to enhance subject's cooperation during training sessions, the robot should allow deviation in the prescribed path depending on the subject's modified limb motions subsequent to the disability. In the present work, an interactive training paradigm based on the impedanc...","Title: Design optimization of a cable actuated parallel ankle rehabilitation robot: A fuzzy based multi-objective evolutionary approach.\nYear: 2016\n\nAbstract: Robotic devices can be potentially used to assist physical therapy treatments in order to restore musculoskeletal system malfunctions owing to neurological disorders. Cable actuated parallel robots, despite their obvious benefits such as enhanced workspace, light weight, and flexibility, are not popularly used in ankle rehabilitation treatments, due to their complex mechanism and cable actuation issues. In order to address these issues, it is recommended to carry out robot design optimization. However, design synthesis of the cable actuated parallel ankle robot calls for multi-objective optimization (MOO), since there are multiple and conflicting objectives to achieve. To acquire more choices between actuator forces, overall stiffness of robot (which is crucial for a cable based ankle robot) and other vital design objectives, it is required to explore the extreme ends of the Pareto Front (PF) more carefully. Existing multi-objective evolutionary algorithms (MOEAs) normally focus on the convergence and may not provide solutions at the extremities of PF. Capitalizing on this improvement opportunity, this paper presents a fuzzy based MOEA, namely, biased fuzzy sorting genetic algorithm (BFSGA) which encourages solutions in the extreme zones of the PF. It is shown in this paper that using proposed method, diversity in the populations is supported and in the process wider trade-off choices of objectives can be obtained. During ankle robot design optimization, crisp objectives are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS). Subsequently OAS is used to assign a fuzzy dominance ranking to the design solutions. It is found that the BFSGA approach performs well in exploring the extreme zones of the Pareto front, which are normally overlooked by other MOEA such as NSGA-II due to their inherent mechanism.","Title: Threshold analysis of design metrics to detect design flaws: student research abstract.\nYear: 2016\n\nAbstract: Detection of design flaws at different granularity levels of software can help the software engineer to reduce the testing efforts and maintenance cost. In the context of metric-based analysis, current state of art for the quality assurance tools is to extract the metrics from the source code and analyzed the design complexity. But in case of legacy systems, a software engineer needs to pass through the re-engineering process. In this study, I propose a methodology to investigate the threshold effect of software design metrics in order to detect design flaws and its effect over the granularity level of software. Moreover, I will use some statistical methods and machine learning techniques to derive and validate the effect of thresholds over the NASA and open source datasets retrieve from the PROMISE repository.","Title: Empirical investigation of fault predictors in context of class membership probability estimation.\nYear: 2016\n\nAbstract: In the domain of software fault prediction, class membership probability of a selected classifier and the factors related to its estimation can be considered as necessary information for tester to take informed decisions about software quality issues. The objective of this study is to empirically investigate the class membership probability estimation capability of 15 classifiers/fault predictors on 12 datasets of open source projects retrieved from PROMISE repository. We empirically validate the effect of dataset characteristics and set of metrics on the performance of classifiers in estimating the class membership probability. We used Receiver Operating Characteristics-Area under Curve (ROC-AUC) value and overall accuracy as benchmarks to evaluate and compare the performance of classifiers. We apply Friedman's, post-hoc Nemenyi and Analysis of Means (ANOM) test to compare the significant performance of classifiers. We conclude that ADTree and RandomForest outperform, while ZeroR classifier cannot show significant performance for estimation of class membership probability.","Title: A Methodology to Automate the Selection of Design Patterns\nYear: 2016\n\nAbstract: Background: Over the last two decades, numerous software design patterns have been introduced and cataloged on the basis of developer's interest and skills. Motivation: In software design phase, inexperienced designers are mostly concerned on how to select an appropriate design pattern from the catalog of relevant patterns in order to solve a design problem. The existing automated design pattern selection methodologies are limited to the need of formal specification of design patterns or an appropriate sample size to make the learning process more effective. Method: To address this concern, we propose a three step methodology to automate the selection process of design pattern for a design problem. The steps of the methodology are text preprocessing, use of an unsupervised learning technique (that is Fuzzy c-Mean) as a core function to quantitatively determine the resemblance of different objects and selection of most appropriate pattern for a design problem. We evaluate our methodology with two samples that is Gang-of-Four (GoF) design pattern and spoiled pattern collection, and three object-oriented related design problems. Moreover, we used Fuzzy Silhouette test, Kappa (k) test, Cosine Similarity and argmax function to measure the effectiveness of our methodology. Results: In case of GoF pattern collection, we validated the reliability of Fuzzy c-Mean (FCM) results using a classification decision tree, and observed promising results compared to other automation techniques. Conclusion: From the comparison results, we observed 11%, 4% and 18% improvement in the performance of proposed technique as compared to supervised learning techniques of Support Vector Machine, Naïve Bayes and C4.5 respectively.","Title: A Boundary Property For Upper Domination\nYear: 2016\n\nAbstract: An upper dominating set in a graph is a minimal (with respect to set inclusion) dominating set of maximum cardinality. The problem of finding an upper dominating set is generally NP-hard, but can be solved in polynomial time in some restricted graph classes, such as P-4- free graphs or 2K(2)-free graphs. For classes defined by finitely many forbidden induced subgraphs, the boundary separating difficult instances of the problem from polynomially solvable ones consists of the so called boundary classes. However, none of such classes has been identified so far for the upper dominating set problem. In the present paper, we discover the first boundary class for this problem.","Title: Totally optimal decision trees for Boolean functions.\nYear: 2016\n\nAbstract: We study decision trees which are totally optimal relative to different sets of complexity parameters for Boolean functions. A totally optimal tree is an optimal tree relative to each parameter from the set simultaneously. We consider the parameters characterizing both time (in the worst- and average-case) and space complexity of decision trees, i.e., depth, total path length (average depth), and number of nodes. We have created tools based on extensions of dynamic programming to study totally optimal trees. These tools are applicable to both exact and approximate decision trees, and allow us to make multi-stage optimization of decision trees relative to different parameters and to count the number of optimal trees. Based on the experimental results we have formulated the following hypotheses (and subsequently proved): for almost all Boolean functions there exist totally optimal decision trees (i) relative to the depth and number of nodes, and (ii) relative to the depth and average depth.","Title: Upper Domination: towards a dichotomy through boundary properties.\nYear: 2018\n\nAbstract: An upper dominating set in a graph is a minimal dominating set of maximum cardinality. The problem of finding an upper dominating set is generally NP-hard. We study the complexity of this problem in finitely defined classes of graphs and conjecture that the problem admits a complexity dichotomy in this family. A helpful tool to study the complexity of an algorithmic problem is the notion of boundary classes. However, none of such classes has been identified so far for the upper dominating set problem. We discover the first boundary class for this problem and prove the dichotomy for monogenic classes.","Title: Detection of Fault-Prone Classes Using Logistic Regression Based Object-Oriented Metrics Thresholds\nYear: 2016\n\nAbstract: Background: In the plethora of studies, the object-orientedmetrics have been empirically validated to assess the design properties and quantify the high-level quality attributes such as fault-proneness, either at the method or class granularity levels of software. Motivation: A more precise value of an object-oriented metric can be used as an indicator for the developers tomake the informed decisions regarding the detection of design flaws and classify the fault-proneness classes. Method: Bender used an approach in the domain of epidemiology studies to derivethe threshold values for the risk factors. In our study, we follow the Bender's approach and propose a model to derive the thresholds for a set of software design metrics via non-linearfunctions, which are described through logistic regressioncoefficients. Subsequently, we perform four types of analysis and three experiments in order to evaluate and compare the effectiveness of derived thresholds in the domain of classificationof fault proneness classes. We use the Precision, Recall, Fmeasureand classification accuracy performance measures toassess the effectiveness of derived metrics thresholds. Results: We compare the derive threshold values of DIT, CA, LCOM andNPM metrics with their existing data distribution basedthreshold values, and observed the significant increase in the classification accuracy of fault-prone classes. For example, DIT(27%), Ca (2%), NPM (2%) and LCOM (15%) for the Ant-1.5project. Conclusion: The analysis results suggest that the proposed model can be applied to derive the thresholds of otherobject-oriented metrics which present either with or withoutheavy-tailed distribution, however, the proposed model to derivethresholds cannot generalize for all the systems due to variationin data characteristics.","Title: Assist-as-Needed Control of an Intrinsically Compliant Robotic Gait Training Orthosis.\nYear: 2017\n\nAbstract: It is a common hypothesis in the field of robot-assisted gait rehabilitation that the active involvement and voluntary participation of neurologically impaired subjects in the robotic gait training process may enhance the outcomes of such therapy. An adaptive seamless assist-as-needed (AAN) control scheme was developed for the robotic gait training. The AAN control scheme learns in real time the d...","Title: A Framework for Ranking of Software Design Patterns.\nYear: 2017\n\nAbstract: Several software design patterns have been familiarized either in canonical or as variant solutions in order to solve a problem. Novice designers mostly adopt patterns without considering their ground reality and relevancy with design problems, which may cause to increase the development and maintenance efforts. In order to realize the ground reality and to automate the selection process, the existing automated systems for the selection of design patterns either need formal specification or precise learning through training the numerous classifiers. In order to address this issue, we propose an approach on the base of a supervised learning technique named 'Learning to Rank', to rank the design patterns with respect to text similarity with the description of the given design problems. Subsequently, we also propose an evaluation model in order to assess the effectiveness of the proposed approach. We evaluate the effectiveness of the proposed approach in the context of several design pattern collections and relevant design problems. The promising experimental results indicate the applicability of the proposed approach.","Title: A methodology to predict the instable classes: student research abstract.\nYear: 2017\n\nAbstract: Class stability is intrinsically characterized by the evolution of a number of dependencies and change propagation factors used to promote the ripple effect. In this regard, historical information regarding change propagation factors can aid to identify the classes prone to ripple effect (that is instable classes). In this paper, we propose a methodology to exploit the versions history of change propagation factors in order to predict the instable classes. Initially, we have implemented the proposed methodology with version history of three open source projects MongoDB Java Driver, Google Guava and Apache MyFaces and obtained promising results as compared to existing stability assessors. Subsequently, the experimental results indicate that proposed methodology can be used to identify the classes prone to ripple effect and can aid developers to reduce the efforts needed to maintain and evolve the system.","Title: Towards a hypothetical framework of humans related success factors for process improvement in global software development: systematic review.\nYear: 2017\n\nAbstract: Presently, the majority of the software development organizations are adopting the phenomena of Global Software Development (GSD), mainly because of the significant return on investment it produces. However, GSD is a complex phenomenon and there are many challenges associated with it, especially that related to Software Process Improvement (SPI). The aim of this work is to identify humans' related factors that can positively impact the SPI process in GSD organizations and proposed a hypothetical framework of the identified success factors in relation to SPI implementation. We have adopted the Systematic Literature Review (SLR) method in order to identify the success factors. Using the SLR approach, total ten success factors were identified. The paper also reported the Critical Success Factors (CSFs) for SPI implementation following the criteria of the factors having a frequency ≥ 50% as critical. Our results reveal that five out of ten factors are critical for SPI program. Based on the analysis of the identified success factors, we have presented a hypothetical framework that has highlighted an association between the identified success factors and the implementation of the SPI program in GSD environment.","Title: Software design patterns classification and selection using text categorization approach.\nYear: 2017\n\nAbstract: •The proposed approach aid to introduce an automated system for the classification and selection of software design patterns.•The proposed approach is exploited via Fuzzy c-means unsupervised learning technique.•We leverage an approach to introduce a new feature selection method named Ensemble-IG.•An evaluation model to assess the effectiveness of the proposed approach using three widely known design pattern collection.","Title: The Effect of Gang-of-Four Design Patterns Usage on Design Quality Attributes\nYear: 2017\n\nAbstract: Context: In the plethora of studies, it has been empirically investigated that the incidence of design pattern instances can be considered as an indicator to elaborate the software design. The developers, who have more concern with design quality, are interested to know the effect of use intensity of design patterns on the system level design quality attributes. Goal: The objective of our study is to empirically investigate the effect of the frequent use of the Gang-of-Four (GoF) design patterns on the design quality attributes. Method: We perform a case study which includes three analyses in order to investigate, 1) the existence of a correlation between design pattern usage and design quality attributes, 2) the confounding effect of system size (number of classes) on the correlation, and 3) how the change in number of employed design pattern instances affects the design quality in the subsequent releases of a system. Results: The result of this study suggests that the reusability, flexibility and understandability have a significant relationship with the employed instances of Template, Adapter-Command, Singleton and State-Strategy design patterns, however, it is affected by the confounding effect of system size. Subsequently, in the subsequent releases of an open source project named velocity, we observed the use intensity of Singleton, Adapter-Command, and State-Strategy design patterns can improve the design quality in term of reusability and flexibility attributes.","Title: Review on Design and Control Aspects of Robotic Shoulder Rehabilitation Orthoses.\nYear: 2017\n\nAbstract: Robotic rehabilitation devices are more frequently used for the physical therapy of people with upper limb weakness, which is the most common type of stroke-induced disability. Rehabilitation robots can provide customized, prolonged, intensive, and repetitive training sessions for patients with neurological impairments. In most cases, the robotic exoskeletons have to be aligned with the human join...","Title: Improving the Quality of Software Development Process by Introducing a New Methodology-AZ-Model.\nYear: 2018\n\nAbstract: Quality is the most important factor for software development as it mainly defines customer satisfaction that is directly related to the success of a software project. The software process model is used to ensure software quality, represent a variety of task settings, manage project duration, improve the process and range to execute the process understanding, and to appropriate implicit conjecture for all task settings. Several software processes models exist in software albeit with limited scope. Given this viewpoint, this paper presents a new software development life cycle model, \"AZ-Model,\" for software development by introducing new activities during software development life cycle. It overcomes the limitations of traditional models and significantly impacts the production of a quality product in a time-box. This paper also presents a comprehensive comparative study and statistical analyses to examine the significance of AZ-Model for software development.","Title: Correlation between the Frequent Use of Gang-of-Four Design Patterns and Structural Complexity\nYear: 2017\n\nAbstract: The structural complexity of design components (e.g. Classes) is proportional to design quality at the system level and is quantified via the object-oriented metrics. The frequent use of design patterns causes of too much abstraction and can increase the structural complexity of design components. Though, in our previous work, we have empirically investigated the impact of use intensity of design pattern on the system level quality attributes. However, the empirical investigation of the effect of usage of design patterns on the design properties is still required. In this regard, we conduct an empirical study and perform a case study which includes the analysis 1) the existence of a correlation between design pattern usage and design metrics, 2) the confounding effect of system size (number of classes) on the correlation, and 3) how the change in number of employed design pattern instances affects the structural complexity in the subsequent releases of a system. The result of this study suggests that structural complexity associated with aggregation, coupling, functional abstraction design properties has a significant relationship with the employed instances of Template, Adapter-Command, Singleton, and Factory Method design patterns.","Title: Counter Measuring Conceivable Security Threats on Smart Healthcare Devices.\nYear: 2018\n\nAbstract: Smart devices, the carriers of a huge amount of private, sensitive and confidential data are pervasive in today's world with innovative and enhanced functionalities. Smartphones have brought tremendous change in people's lives with the launch of a new platform of communication and an ease of access to a wide range of applications. Due to the swift increase in the users of Android smartphones and the increasing demands based on advanced ease and features, developers are working hard to achieve the needful. Easy access to certain features and applications gave rise to the powerfulness and an efficacy of various threats, risks and vulnerabilities that can victimize users' private data residing in smartphone paradigm. With the developments and enhancements in malware, for Android-based smartphones, attacks continue to occur. In this paper, we investigate one of the possibly most destructive attacks for Android, that is, screenshot attack. We have developed \"ScreenStealer\" application and explored the vulnerabilities which make Android more inclined to risks and threats. Furthermore, we evaluated capture ratio of screenshots, resources consumption and execution time to determine effectiveness, efficiency and stealthiness of such a malicious application.","Title: Effect of Project Management in Requirements Engineering and Requirements Change Management Processes for Global Software Development.\nYear: 2018\n\nAbstract: Presently, global software development (GSD) is growing very rapidly. However, it is not an easy and straightforward process. Requirements engineering (RE) and requirements change management (RCM) both are considered as very challenging activities due to demanding rich communications. Because it is necessary to address geographical and cultural differences in GSD, this requirement makes RE and RCM challenging. This paper investigates the importance of project management in RE and RCM processes. First, the frameworks with the phenomena of specialized project management are proposed for RE and RCM. Then, a survey and blind interviews of the experts are conducted to validate the proposed frameworks. Finally, statistical tools are applied to analyze the collected data. By utilizing the analyzed data, our results show the significant impacts of both frameworks (i.e., RE and RCM) in the GSD environment.","Title: Implications of deep learning for the automation of design patterns organization.\nYear: 2018\n\nAbstract: Though like other domains such as email filtering, web page classification, sentiment analysis, and author identification, the researchers have employed the text categorization approach to automate organization and selection of design patterns. However, there is a need to bridge the gap between the semantic relationship between design patterns (i.e. Documents) and the features which are used for the organization of design patterns. In this study, we propose an approach by leveraging a powerful deep learning algorithm named Deep Belief Network (DBN) which learns on the semantic representation of documents formulated in the form of feature vectors. We performed a case study in the context of a text categorization based automated system used for the classification and selection of software design patterns. In the case study, we focused on two main research objectives: 1) to empirically investigate the effect of feature sets constructed through the global filter-based feature selection methods besides the proposed approach, and 2) to evaluate the significant improvement in the classification decision (i.e. Pattern organization) of classifiers using the proposed approach. The adjustment of DBN parameters such as a number of hidden layers, nodes and iteration can aid a developer to construct a more illustrative feature set. The experimental promising results suggest the significance of the proposed approach to construct a more representative feature set and improve the classifier’s performance in terms of organization of design patterns.","Title: An Integrated Planning Approach Towards Home Health Care, Telehealth and Patients Group Based Care.\nYear: 2018\n\nAbstract: The availability of patient-centered, cost effective, and quality oriented health care is a huge task for the health care planners in every country. In this study, a Home Health Care (HHC) planning problem is introduced to integrate the resource dimensioning issues and assignment aspects with the telehealth based care and patients' group-based care services. An integer linear programming model is developed and solved through CPLEX. The main aims of the proposed model are: (i) to provide an optimal selection of locations for HHC offices, health care workers, and patients' cluster centres besides their specific assignment; (ii) to schedule the health care session for each patient or patients' group by creating a pair of HHC nurse and telehealth staff against a specific time window; and (iii) to seek the enhancement of patient satisfaction and quality of service considering the penalties for violation of patients' preferences and inappropriate experience gap between the pair of nurses. Subsequently, in order to validate the effectiveness of the proposed integration approach, we employ the Fuzzy c-means to describe the appropriate organization of the HHC offices, health care workers, and patient's data. Finally, a sensitivity analysis is performed to explore the model behavior against the variation in parameter values. The detailed analysis of the results shows the effectiveness of the proposed model and its behavior with respect to different types of cost.","Title: Automated framework for classification and selection of software design patterns.\nYear: 2019\n\nAbstract: Though, Unified Modeling Language (UML), Ontology, and Text categorization approaches have been used to automate the classification and selection of design pattern(s). However, there are certain issues such as time and effort for formal specification of new patterns, system context-awareness, and lack of knowledge which needs to be addressed. We propose a framework (i.e. Three-phase method) to discuss these issues, which can aid novice developers to organize and select the correct design pattern(s) for a given design problem in a systematic way. Subsequently, we propose an evaluation model to gauge the efficacy of the proposed framework via certain unsupervised learning techniques. We performed three case studies to describe the working procedure of the proposed framework in the context of three widely used design pattern catalogs and 103 design problems. We find the significant results of Fuzzy c-means and Partition Around Medoids (PAM) as compared to other unsupervised learning techniques. The promising results encourage the applicability of the proposed framework in terms of design patterns organization and selection with respect to a given design problem.","Title: Evolutionary Optimization Using Equitable Fuzzy Sorting Genetic Algorithm (EFSGA).\nYear: 2019\n\nAbstract: This paper presents a fuzzy dominance-based analytical sorting method as an advancement to the existing multi-objective evolutionary algorithms (MOEA). Evolutionary algorithms (EAs), on account of their sorting schemes, may not establish clear discrimination amongst solutions while solving many-objective optimization problems. Moreover, these algorithms are also criticized for issues such as uncertain termination criterion and difficulty in selecting a final solution from the set of Pareto optimal solutions for practical purposes. An alternate approach, referred here as equitable fuzzy sorting genetic algorithm (EFSGA), is proposed in this paper to address these vital issues. Objective functions are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS) based on their respective fuzzy objective values. Subsequently, OAS is used to assign an explicit fuzzy dominance ranking to these solutions for improved sorting process. Benchmark optimization problems, used as case studies, are optimized using proposed algorithm with three other prevailing methods. Performance indices are obtained to evaluate various aspects of the proposed algorithm and present a comparison with existing methods. It is shown that the EFSGA exhibits strong discrimination ability and provides unambiguous termination criterion. The proposed approach can also help user in selecting final solution from the set of Pareto optimal solutions.","Title: Systematic Literature Reviews of Software Process Improvement: A Tertiary Study.\nYear: 2017\n\nAbstract: Systematic Literature Review (SLR) is becoming a vital part of present day research in software process improvement (SPI). Nevertheless, there is no available study that provides detail review of the published software process improvement SLRs. Objective: The aim of this article is to classify the SLRs of SPI in order to identify the main research areas covered and evaluate the quality of the published SLRs. Methodology: A tertiary study was conducted to review the SLRs published by other researchers on the topic of SPI. Results: Twenty-four SLR articles were identified in the field of SPI. Results show that the quality of the selected SLRs on SPI is decreasing over the recent years. The most popular research topics are factors affecting SPI and process models. Conclusions: This study provides the review and state of the art in the context of SPI research. The results of this article would be of great interest for future SPI researchers by providing in depth understanding of various research areas in SPI. The number of process improvement SLRs is increasing and the overall quality is decreasing, which could lessen their potential impact on SPI practice. Currently, SPI literature is weak in the knowledge areas such as quality and software testing process improvement.","Title: Bi-criteria optimization of decision trees with applications to data analysis.\nYear: 2018\n\nAbstract: •Algorithms for bi-criteria optimization of decision trees are created.•We compare twenty greedy heuristics for bi-criteria optimization of decision trees.•We discover very small number of Pareto optimal points for an optimization problem.","Title: Statistical Analysis of the Effects of Heavyweight and Lightweight Methodologies on the Six-Pointed Star Model.\nYear: 2018\n\nAbstract: Traditionally, software development organizations relied on heavyweight development methodologies, such as waterfall, V-model, and others. Later, agile development methodologies known as lightweight methodologies were introduced. Many considered these to be more flexible and more effective than heavyweight methodologies. Both methodologies are equally important for a software development life cycle. The purpose of adopting software development methodologies is to optimize the process model to achieve milestones while concurrently and effectively managing time, budget, and quality. The literature review reveals that there is a lack of statistical evidence for determining the effect of both methodologies on the six-pointed star model (schedule, scope, budget, risk, resource, and quality). In this paper, statistical comparisons were performed for the effects of both methodologies on each factor of the six-pointed star model and the interdependency among factors. Numerical analyses were conducted based on survey responses collected from the experienced users of both methodologies. After examining the results of all the factors of both methodologies, it was determined that lightweight methodologies are suitable for small-scale projects and that heavyweight methodologies perform better for medium- and large-scale projects.","Title: Systematic literature study for dimensional classification of success factors affecting process improvement in global software development: client-vendor perspective.\nYear: 2018\n\nAbstract: The majority of organisations are globalising their software development activities by following the ideas of global software development (GSD). The motivation behind the adoption of GSD phenomena are the list of benefits gained by the software industry. However, there are different challenges face by the GSD organisations, particularly the issues related to software process improvement (SPI). The...","Title: Knowledge based quality analysis of crowdsourced software development platforms\nYear: 2019\n\nAbstract: As an emerging and promising approach, crowdsourcing-based software development has become popular in many domains due to the participation of talented pool of developers in the contests, and to promote the ability of requesters (or customers) to choose the ‘wining’ solution with respect to their desired quality levels. However, due to lack of a central mechanism for team formation, continuity in the developer’s work on consecutive tasks and risk of noise in submissions of a contest, there is a gap between the requesters of a domain and their quality concerns related to the adaptation of a crowdsourcing-based software development platform. In order to address concerns and aid requesters, we describe three measures; Quality of Registrant Developers (QRD), Quality of Contest (QC) and Quality of Support (QS) to compute and predict the quality of a crowdsourcing-based platform through historical information on its completed tasks. We evaluate the capacity of the QRD, QC and QS as assessors to predict the quality. Subsequently, we implement a crawler to mine the information of completed development tasks from the TopCoder platform to inspect the proposed measures. The promising results of our QRD, QC, and QS measures suggest to use the proposed measures to the requesters and researchers of other domains such as pharmaceutical research and development, in order to investigate and predict the quality of crowdsourcing-based software development platforms.","Title: GSEPIM: A roadmap for software process assessment and improvement in the domain of global software development\nYear: 2019\n\nAbstract: Software development firms have begun adopting the practice of global software development (GSD). The main reason for the shift toward globalization is the various benefits received by software development firms. However, there are several issues faced by GSD organizations, particularly those associated with software process improvement (SPI). It has been noticed that a formal process improvement approach could assist in successfully executing development activities in GSD. The core objective of this research work is to develop a global software engineering process improvement model (GSEPIM) to assess and improve software process activities in a GSD environment. The proposed model will be developed based on existing models in other domains, an empirical study conducted with GSD practitioners, and an understanding of critical success factors and challenges of SPI. In this study, the first step in the development of GSEPIM is completed by identifying the challenges of SPI in GSD and presenting a solution in the form of a robust framework.","Title: A methodology to rank the design patterns on the base of text relevancy\nYear: 2019\n\nAbstract: Several software design patterns have cataloged either with canonical or as variants to solve a recurring design problem. However, novice designers mostly adopt patterns without considering their ground reality and relevance to design problems, which causes to increase the development and maintenance efforts. The existing automated systems to select the design patterns need either high computing effort and time for the formal specification or precise learning through the training of several classifiers with large sample size to select the right design patterns realized on the base of their ground reality. In order to discuss this issue, we propose a method on the base of a supervised learning technique named ‘Learning to Rank’, to rank the design patterns via the text relevancy with the description of the given design problems. Subsequently, we also propose an evaluation model to assess the effectiveness of the proposed method. We evaluate the efficacy of the proposed method in the context of several design pattern collections and relevant design problems. The promising experimental results indicate the applicability of the proposed method as a recommendation system to select the right design pattern(s).","Title: A Step towards the Improvement in the Performance of Text Classification.\nYear: 2019\n\nAbstract: The performance of text classification is highly related to the feature selection methods. Usually, two tasks are performed when a feature selection method is applied to construct a feature set; 1) assign score to each feature and 2) select the top-N features. The selection of top-N features in the existing filter-based feature selection methods is biased by their discriminative power and the empirical process which is followed to determine the value of N. In order to improve the text classification performance by presenting a more illustrative feature set, we present an approach via a potent representation learning technique, namely DBN (Deep Belief Network). This algorithm learns via the semantic illustration of documents and uses feature vectors for their formulation. The nodes, iteration, and a number of hidden layers are the main parameters of DBN, which can tune to improve the classifier's performance. The results of experiments indicate the effectiveness of the proposed method to increase the classification performance and aid developers to make effective decisions in certain domains.","Title: Prediction of Drug Target Sensitivity in Cancer Cell Lines Using Apache Spark.\nYear: 2019\n\nAbstract: Predicting the drug targets in the base of cancer cell line is one of the hottest issues in cancer treatment. Drug sensitivity describes which drug is perfect for cell line in certain condition or disease. This condition exists due to change in human metabolism. Different techniques are used for cancer treatment such as radiotherapy, hormone therapy, chemotherapy, and surgery. Many statistical methods and machine learning algorithms such as support vector machine, principal component analysis (PCA), logistic regression, simple linear regression, naive Bayes classifier, generalized linear regression, and random forest have been used for drug target prediction. However, these predictors take more time for computation using different tools such as MATLAB and R tool. In this study, different machine learning techniques are applied using Apache Spark to predict drug targets. Apache Spark uses the resilient distributed dataset (RDD) technique for in-memory fast computation and fault tolerance. The obtained results indicate that Spark provides better accuracy in short time when compared with existing tools.","Title: Analytics of Heterogeneous Breast Cancer Data Using Neuroevolution.\nYear: 2019\n\nAbstract: Breast cancer prognostic modeling is difficult since it is governed by many diverse factors. Given the low median survival and large scale breast cancer data, which comes from high throughput technology, the accurate and reliable prognosis of breast cancer is becoming increasingly difficult. While accurate and timely prognosis may save many patients from going through painful and expensive treatments, it may also help oncologists in managing the disease more efficiently and effectively. Data analytics augmented by machine-learning algorithms have been proposed in past for breast cancer prognosis; and however, most of these could not perform well owing to the heterogeneous nature of available data and model interpretability related issues. A robust prognostic modeling approach is proposed here whereby a Pareto optimal set of deep neural networks (DNNs) exhibiting equally good performance metrics is obtained. The set of DNNs is initialized and their hyperparameters are optimized using the evolutionary algorithm, NSGAIII. The final DNN model is selected from the Pareto optimal set of many DNNs using a fuzzy inferencing approach. Contrary to using DNNs as the black box, the proposed scheme allows understanding how various performance metrics (such as accuracy, sensitivity, F1, and so on) change with changes in hyperparameters. This enhanced interpretability can be further used to improve or modify the behavior of DNNs. The heterogeneous breast cancer database requires preprocessing for better interpretation of categorical variables in order to improve prognosis from classifiers. Furthermore, we propose to use a neural network-based entity-embedding method for categorical features with high cardinality. This approach can provide a vector representation of categorical features in multidimensional space with enhanced interpretability. It is shown with evidence that DNNs optimized using evolutionary algorithms exhibit improved performance over other classifiers mentioned in this paper.","Title: A Methodology to Rank the Patients Prone to Chronic Diseases in Telehealth\nYear: 2019\n\nAbstract: Context: From last decade, telehealth research community have started to use machine learning techniques to automate the certain aspects of healthcare systems for prediction of patients prone to chronic diseases such as checking of insulin level, cancer, and monitoring blood-glucose levels. Though existing automated systems aid the telehealth practitioner, however high computing effort, time, and cost is required in terms of several classifiers, multi class problem, or large sample size to obtained results on the basis of ground reality. Goal: We work on this concern and propose a methodology which is employed via \"Learning to Rank\" (i.e., a supervised learner) to rank the patients on the basis of their data relevancy. We also propose a model to investigate the efficacy of the proposed method. We assess tie efficacy of the proposed method with seven public datasets associated with certain diseases. Datasets are retrieved from UCI repository Machine Learning Repository. Results: We observed LambdaMART outperform than AdaRank and Coordinate Ascent with a minor difference in terms of NDCG (Normalized Discounted Cumulative Gain) and MAP (Mean Average Precision) to predict patients prone to chronic diseases. Conclusion: The results of study indicates the usage of the proposed method as a recommendation system to rank the patients on the basis of their severity level.","Title: Methodology For The Quantification Of The Effect Of Patterns And Anti-Patterns Association On The Software Quality\nYear: 2019\n\nAbstract: The employment of design patterns is considered as a benchmark of software quality in terms of reducing the number of software faults. However, the quantification of the information about the hinder design issues such as the number of roles, type of design pattern, and their association with anti-pattern classes is still required. The authors propose a new methodology to evaluate the impact of certain design issues on the software quality in terms of quantification of fault density. Firstly, they mine the required information about the classes of each system under study. Secondly, they describe taxonomy to group the classes. Subsequently, they used statistical techniques to formulate and benchmark the results. They include the analysis of four open source projects with six design patterns and six anti-patterns in the case study. The main consequences are (i) the pattern participant classes are less dense in faults, (ii) the classes involved in the structural association between design patterns and anti-patterns are denser in faults, (iii) the pattern participant classes with multi-role and anti-pattern smell association is denser in faults as compared to others. The significant difference between fault density distributions of groups of classes is still unclear and required further empirical investigation.","Title: A new auxiliary information based cumulative sum median control chart for location monitoring.\nYear: 2019\n\nAbstract: Control charts are commonly used tools in statistical process control for the detection of shifts in process parameters. Shewhart-type charts are efficient for large shift values, whereas cumulative sum (CUSUM) charts are effective in detecting medium and small shifts. Control chart use commonly assumes that data are free of outliers and parameters are known or correctly estimated based on an in-control process. In practice, these assumptions are not often true because some processes occasionally have outliers. Monitoring the location parameter is usually based on mean charts, which are seriously affected by violations of these assumptions. In this paper we propose several CUSUM median control charts based on auxiliary variables, and offer comparisons with their corresponding mean control charts. To monitor the location parameter, we examined the performance of mean and median control charts in the presence and absence of outliers. Both symmetric and non-symmetric processes were studied to examine the properties of the proposed control charts to monitor the location parameter using CUSUM control charts. We used different run length measures to study in-control and out-of-control performances of CUSUM charts. Results revealed that our proposed control charts perform much better than the traditional charts in the presence of outliers. A real application of our study was provided using data on concrete compressive strength as it relates to the quality of cement manufacturing.","Title: Efficient Power Management Algorithm Based on Fuzzy Logic Inference for Electric Vehicles Parking Lot.\nYear: 2019\n\nAbstract: Smart grid is expected to support electric vehicles parking lots with the existing power line infrastructure. In order to support all electric-vehicles (EVs) users to complete their charging needs before leaving the parking lot, the power grid requires that the charging demands of EVs should be within the allowable power limit to avoid the grid overloading. This paper proposes a fuzzy logic inference based algorithm (FLIA) to manage the available power efficiently for EVs in the parking lot. The problem is mathematically formulated and solved by the credibility of the fuzzy inference mechanism to control charging and discharging of the EVs. The key idea is to introduce the fuzzy inference mechanism that evaluates several uncertain input parameters from the electric grid and from EVs to obtain an adequately accurate charging or discharging decision for each of the connected EVs. The proposed scheme is applied to a parking lot with different parking capacities and compared with the conventional-based systems. The simulation results demonstrated the feasibility and effectiveness of the proposed algorithm when dealing with the available power management and satisfying the EV user's requirements.","Title: A methodology to characterize and compute correlation between traffic congestion and health issues via social media\nYear: 2018\n\nAbstract: Traffic congestion is one of the most significant problems around the world. Literature shows various analyses of real time traffic incidents detection and crowd sensing. However, few researchers quantified the traffic congestion impacts on public health. To the best of our knowledge, there is no study, which determines the correlation between traffic congestion and public health issues via social media. In this paper, we propose a methodology to compute the correlation between traffic congestion and public health issues through social media analysis. To purse this task, we have used topic modeling and sentimental analysis. We mined a collection of 97 million tweets extracted from Twitter. Subsequently, different filters are applied to get the most traffic-congested locations around the world and the top health issues in the corresponding areas. Additionally, we have performed sentimental analysis to get the public perception about the initiatives taken to improve the health issues in those regions. We have found 36 most traffic congested cities around the world, such as Mexico, Bangkok, Jakarta and Chongqing etc. Apart from that, heart diseases, respiratory and psychological problems are identified as the common problems in traffic congested cities. Almost 71% public comments shows the negative sentiments. Which reflects their level of frustration about the steps taken to reduce the traffic by the higher authorities.","Title: Empirical Investigation of Code Quality Rule Violations in HPC Applications\nYear: 2021\n\nAbstract: In large, collaborative open-source projects, developers must follow good coding standards to ensure the quality and sustainability of the resulting software. This is especially a challenge in high-performance computing projects, which admit a diverse set of contributions over decades of development. Some successful projects, such as the Portable, Extensible Toolkit for Scientific Computation (PETSc), have created comprehensive developer documentation, including specific code quality rules, which should be followed by contributors. However, none of the widely used and highly active open-source HPC projects have a way to automatically check whether these rules, typically expressed informally in English, are being violated. Hence, compliance checking is labor-intensive and difficult to ensure. To address this issue, we propose an automated method for detecting rule violations in HPC applications based on the PETSc development rules. In our empirical study, we consider 46 PETSc-based applications and assess the violations of two C-usage rules. The experimental results demonstrate the efficacy of the proposed method in identifying PETSc rule violations, which can be broadened to other HPC frameworks and extended by us and others in the community to include more rules.","Title: Entropy-Based Greedy Algorithm For Decision Trees Using Hypotheses\nYear: 2021\n\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses of values of all attributes. Such decision trees are similar to those studied in exact learning, where membership and equivalence queries are allowed. We present greedy algorithm based on entropy for the construction of the above decision trees and discuss the results of computer experiments on various data sets and randomly generated Boolean functions.","Title: An efficient encoder–decoder model for portrait depth estimation from single images trained on pixel-accurate synthetic data\nYear: 2021\n\nAbstract: Depth estimation from a single image frame is a fundamental challenge in computer vision, with many applications such as augmented reality, action recognition, image understanding, and autonomous driving. Large and diverse training sets are required for accurate depth estimation from a single image frame. Due to challenges in obtaining dense ground-truth depth, a new 3D pipeline of 100 synthetic virtual human models is presented to generate multiple 2D facial images and corresponding ground truth depth data, allowing complete control over image variations. To validate the synthetic facial depth data, we propose an evaluation of state-of-the-art depth estimation algorithms based on single image frames on the generated synthetic dataset. Furthermore, an improved encoder–decoder based neural network is presented. This network is computationally efficient and shows better performance than current state-of-the-art when tested and evaluated across 4 public datasets. Our training methodology relies on the use of synthetic data samples which provides a more reliable ground truth for depth estimation. Additionally, using a combination of appropriate loss functions leads to improved performance than the current state-of-the-art network performances. Our approach clearly outperforms competing methods across different test datasets, setting a new state-of-the-art for facial depth estimation from synthetic data.","Title: Identification and Authentication in Healthcare Internet-of-Things Using Integrated Fog Computing Based Blockchain Model\nYear: 2021\n\nAbstract: The healthcare Internet-of-Things (IoT) offers many benefits including data transmission in real-time mode, the ability to monitor the physiological state of the patient in a different interval of time. Devices such as blood-pressure monitors, glucose meters, heart monitoring implants, Electroencephalography (EEG), Electrocardiogram (ECG), and Electromyography (EMG) wearable devices allow health providers to collect the patient health information locally and make a real-time decision based on the Patient Health Data (PHD). Hospitals have been adopting the IoT for many years and now they have healthcare IoT devices in patients’ rooms and their bodies. However, the medical agencies, hospitals, and companies do not consider the security risk of healthcare IoT devices connected to a Local Area Network (LAN) or Wide Area Network (WAN). The IoT devices can be easily hacked and may lead to several potentially life-threatening risks due to poor authentication and encryption practices. Existing machine learning algorithms and blockchain approach working in the cloud computing environment are unable to meet the Quality of Service (QoS) like reliability, authentication, identification, and security requirements of healthcare IoT devices. Most of the traditional machine learning algorithms and techniques for healthcare IoT lacks the real-world implementation for secure data transmission. Therefore, blockchain is introduced for secure and reliable transaction in healthcare IoT. Whereas Fog Computing (FC) is introduced to extend the services of the cloud at the edge of networks. Integration of FC with blockchain can overcome the issue of healthcare IoT device identification, authentication, and verification for scalable frequent data transmission in a decentralized environment. Hence, a novel solution for the abovementioned problem is proposed using FC and blockchain. It includes an FC-based three-tier architecture, an analytical model, a mathematical framework, and an Advanced Signature-Based Encryption (ASE) algorithm for healthcare IoT device identification, verification, and Patient Health Data (PHD) authentication. The aim is to extend secure data transmission for healthcare IoT and end-users availing the real-time services. The proposed model and algorithm will be able to provide services for transaction and transmission near the edge in a secure manner. By analyzing the generated results from the proposed novel ASE algorithm for throughput, packet error, reliability, and malicious node detection accuracy; it is observed that the ASE algorithm in the FC environment easily outperforms the cloud and the other existing state of the art techniques such as FogBus, Femto cloud, Blockchain Fog-based Architecture Network (BFAN), and BeeKeeper. The malicious node detection accuracy of the ASE algorithm in the FC environment is 91% and in the cloud is 83%. Whereas the reliability percentage of the ASE algorithm in FC is 95% and in the cloud is 87%. The proposed approach is tested on simulators iFogSim (Net-Beans) and SimBlock.","Title: Minimizing Depth of Decision Trees with Hypotheses\nYear: 2021\n\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses about values of all attributes. Such decision trees are similar to ones studied in exact learning, where membership and equivalence queries are allowed. We present dynamic programming algorithms for minimization of the depth of above decision trees and discuss results of computer experiments on various data sets and randomly generated Boolean functions.","Title: A Blockchain-Enabled Fog Computing Model for Peer-To-Peer Energy Trading in Smart Grid\nYear: 2021\n\nAbstract: The advancement in renewable energy sources (RESs) technology have changed the role of traditional consumers to prosumers. In contrast to the traditional power grid, the Smart Grid (SG) network provides a platform for peer-to-peer (P2P) energy trading between prosumers to buy or sell energy according to their requirements. The potential benefits of P2P energy trading can be realized through an efficient service provider of the communication network infrastructure. However, the current communication network is a trustless environment and thereby is unable to fully support the P2P energy trading requirements. Existing techniques in P2P energy trading with blockchain suffers from large network delay due to large network size; this further affects the network performance for P2P trading. In this paper, we present a novel Blockchain-Based Smart Energy Trading (BSET) algorithm along with a Blockchain-Enabled Fog Computing Model (BFCM) for P2P energy trading in Smart Grid. The proposed BSET algorithm provides a fully trusted minimum latency communication network that enables the prosumers to trade energy within their local premises. The algorithm was implemented using iFogSim, Truffle, ATOM, Anaconda, and Geth and evaluated against state-of-the-art communication network models for P2P energy trading. The simulation results revealed the effectiveness in terms of secure trading and network latency.","Title: Minimizing Number of Nodes in Decision Trees with Hypotheses\nYear: 2021\n\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses about values of all attributes. This approach is similar to one studied in exact learning, where membership and equivalence queries are considered. We propose dynamic programming algorithms for the minimization of the number of nodes in such decision trees and discuss results of computer experiments. (C) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://crativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of KES International.","Title: Decision Rules Derived from Optimal Decision Trees with Hypotheses\nYear: 2021\n\nAbstract: Conventional decision trees use queries each of which is based on one attribute. In this study, we also examine decision trees that handle additional queries based on hypotheses. This kind of query is similar to the equivalence queries considered in exact learning. Earlier, we designed dynamic programming algorithms for the computation of the minimum depth and the minimum number of internal nodes in decision trees that have hypotheses. Modification of these algorithms considered in the present paper permits us to build decision trees with hypotheses that are optimal relative to the depth or relative to the number of the internal nodes. We compare the length and coverage of decision rules extracted from optimal decision trees with hypotheses and decision rules extracted from optimal conventional decision trees to choose the ones that are preferable as a tool for the representation of information. To this end, we conduct computer experiments on various decision tables from the UCI Machine Learning Repository. In addition, we also consider decision tables for randomly generated Boolean functions. The collected results show that the decision rules derived from decision trees with hypotheses in many cases are better than the rules extracted from conventional decision trees.","Title: Self-adaptation in smartphone applications: Current state-of-the-art techniques, challenges, and future directions\nYear: 2021\n\nAbstract: Context: In the last few years, smartphones have become an essential part of our lives. Several mobile applications have been uploaded to their respective app stores on daily basis to facilitate the end-users. To ensure the availability of the application and its services, the application needs to be able to detect and deal with various types of changes. Mobile application based self-adaptation is regarded as a solution to handle the above-mentioned chnages. Objective: The objectives of this study are: (i) identification of current state-of-the-art tech-niques, frameworks, models, and algorithms for self-adaptation in mobile applications context, (ii) exploring the core challenges faced in the development of self-adaptive mobile applications, and (iii) conducting a SWOT (Strength Weakness Opportunity Threat) analysis to figure out the research gaps in the targeted research field. Method: To accomplish the mentioned objective, we conducted a systematic literature review to enlighten the need for adaptation in this domain, the targeted areas, their beneficial aspects, state-of-the-art proposed solutions, and their challenges. We performed the keyword-based search on 11 well-known databases to determine the potential studies published between years 2015 to 2020. In total, 31 studies (from 933 potential studies) are selected grounded on the defined inclusion and exclusion criteria. Results: The main findings of this work are: (i) MAPE-K (Monitor Analyze Plan Execute-Knowledge) model is frequently used in several studies due to its resilience, (ii) current work focuses on the android operating system due to its popularity and flexibility; however, it lacks in considering other mobile's operating systems, and (iii) reported work also lacks in mentioning any benchmark (self-adaptive framework). Conclusion: The current study is helpful for the researchers intended to work in the smart-phones domain. From developers viewpoint, this study reports the faced challenges during the development of smartphones applications. Moreover, the performed study is beneficial in filling the identified research gaps by providing a foundation useful to plan future research regarding self-adaptation in smartphone applications context.","Title: Torque Ripples Reduction and Performance Analysis of Electrically Excited Flux Switching Motor\nYear: 2022\n\nAbstract: Torque ripples cause acoustic noise, fluctuation in speed, vibration, and reduce lifetime of the motor. The double salient structure of Flux Switching Motor (FSM) has a high air-gap permeance variation that produces high torque ripples. This paper presents an analytical model to reduce air-gap permeance variation and torque ripples of the proposed octane modular stator 8slots-6poles single-phase Electrically Excited (EE) FSM. Furthermore, the rotor pole shaping technique is used to minimize the air-gap permeance variation and therefore, torque ripples of the proposed design are reduced. The electromagnetic performance of EEFSM is analyzed via the Finite Element Analysis (FEA) method. For the proposed design magnetic flux harmonics are reduced by 71% and back-EMF harmonics are suppressed by 48.5%. Torque ripples of the proposed EEFSM are reduced by 20%, cogging torque is diminished by 42.7% and average torque is enhanced by 5.8%. Finally, the prototype is fabricated and tested experimentally. Calculated values and experimental results are in good agreement and the difference is 3.5%-5%.","Title: A continuum viscoelastic model of Timoshenko NSGT nanobeams\nYear: 2022\n\nAbstract: Developed and solved in this article, for the first time, is a coupled continuum viscoelastic model for Timoshenko nonlocal strain gradient theory (NSGT)-based nanobeams; this is performed using a finite difference analysis (FDA). The viscosity of infinitesimal elements of the Timoshenko NSGT nanobeams is incorporated via the Kelvin-Voigt scheme (as a two-parameter rheological scheme) for both the transverse/longitudinal/rotational motions. The NSGT for the normal/shear stress fields is used for ultrasmall size influences on the continuum model. Rotary inertia is automatically present due to the Timoshenko-type rotation. The viscosity in the Timoshenko NSGT nanobeam is responsible for energy dissipation formulated via negative work. Hamilton's balance scheme is utilised and resulted in the coupled continuum viscoelastic dynamic model for Timoshenko NSGT nanobeams, which is solved via a FDA for nonlinear mechanics. A nonlinear bending test is conducted via development of a finite element method model in the absence of the NSGT.","Title: Investigation of Inner/Outer Rotor Permanent Magnet Flux Switching Generator for Wind Turbine Applications\nYear: 2021\n\nAbstract: In this paper two permanent magnet flux switching generator (PMFSG) is designed for 2 kW output power and 220 V phase voltage at 1500 rpm and comparatively analyzed for wind turbine applications. Both PMFSG share same C-core stator connected back-to-back through flux bridge (beta) with different rotor position i.e., inner rotor PMFSG (IR-PMFSG) and outer rotor PMFSG (OR-PMFSG). A detailed comparative analysis with various beta for both IR-PMFSG and OR-PMFSG are performed under static characteristics, rated condition, overload capability and over-speed capability for generating output voltage, current, power and efficiency. Comparison of the static characteristics reveal that IR-PMFSG offers 47.93% higher rated power, 2.83% higher efficiency, 22.78% more magnetic flux, 56.91% reduced cogging torque and 83.18% lower torque ripples at the cost of 62.69% higher voltage regulation factor. Furthermore, under rated operating condition and overload capability with same specifications it is found that IR-PMFSG exhibits 1.47 times power than that of OR-PMFSG counterpart. Finally, over-speed capability is investigated in term of the output power which shows that IR-PMFSG significantly generate almost 2.25 time of the specification power whereas OR-PMFSG exhibits nearly 1.25 times power. This analysis shows that IR-PMFSG can be operated at wide-speed rage for higher power specification requirements maintaining efficiency greater than 90%.","Title: A Review of Benchmark Datasets and Training Loss Functions in Neural Depth Estimation\nYear: 2021\n\nAbstract: In many applications, such as robotic perception, scene understanding, augmented reality, 3D reconstruction, and medical image analysis, depth from images is a fundamentally ill-posed problem. The success of depth estimation models relies on assembling a suitably large and diverse training dataset and on the selection of appropriate loss functions. It is critical for researchers in this field to be made aware of the wide range of publicly available depth datasets along with the properties of various loss functions that have been applied to depth estimation. Selection of the right training data combined with appropriate loss functions will accelerate new research and enable better comparison with state-of-the-art. Accordingly, this work offers a comprehensive review of available depth datasets as well as the loss functions that are applied in this problem domain. These depth datasets are categorised into five primary categories based on their application, namely (i) people detection and action recognition, (ii) faces and facial pose, (iii) perception-based navigation (i.e., street signs, roads), (iv) object and scene recognition, and (v) medical applications. The important characteristics and properties of each depth dataset are described and compared. A mixing strategy for depth datasets is presented in order to generalise model results across different environments and use cases. Furthermore, depth estimation loss functions that can help with training deep learning depth estimation models across different datasets are discussed. State-of-the-art deep learning-based depth estimation methods evaluations are presented for three of the most popular datasets. Finally, a discussion about challenges and future research along with recommendations for building comprehensive depth datasets will be presented as to help researchers in the selection of appropriate datasets and loss functions for evaluating their results and algorithms.","Title: A Comparative Study of Dual Stator With Novel Dual Rotor Permanent Magnet Flux Switching Generator for Counter Rotating Wind Turbine Applications\nYear: 2022\n\nAbstract: Compared with the single rotor wind turbine, a counter-rotating (CR) wind turbine with two rotor sets leads to twice power density. In this regard, dual stator CR (DSCR) permanent magnet flux switching generator (DSCR-PMFSG) is employed. However, in DSCR-PMFSG both rotor and armature parts are rotating and require slip rings for power transmission. These slip rings associate demerits of constant maintenance, poor speed regulation, increased cost, and additional slip ring losses, whereas DSCR-PMFSG offer lower flux and lesser power density. To overcome the demerits of DSCR-PMFSG as mentioned earlier, this paper proposed a novel dual rotor counter-rotating permanent magnet flux switching generator (DRCR-PMFSG) for wind turbine applications that eliminate the requirements of slip rings and retain brushless operation. The proposed DRCR-PMFSG share one stator connected back-to-back through a flux bridge that provides an alternate flux path between two mechanical ports associated with the inner rotor and outer rotor, contributing to the cumulative output. A detailed comparative analysis of DSCR-PMFSG and DRCR-PMFSG is performed under static characteristics, overload, and wide speed range to generate output power, voltage, current, power density, and efficiency. Quantitative comparative analysis under static analysis evident that proposed DRCR-PMFSG exhibits 33.29% higher flux, suppressed cogging torque and torque ripples up to 53.48% and 67.45%, respectively. Furthermore, a comprehensive quantitative analysis is performed under coupled overload and over-speed capability. Analysis exposes that in comparison with DSCRP-PMFSG, the proposed DRCR-PMFSG improves voltage regulation factor by 55.88%, output current enhanced by 67.9%, raise output voltage to 2.01 times, and power density to 1.72 times while maintaining the efficiency of 90.195% and achieving stable voltage profile with load variation. Finally, a detailed comparative analysis with conventional designs is performed and comprehensive mathematical modelling based on sub-domain model is developed accounting stator slot and rotor pole combinations, magnetic saturation, and winding configuration to validates finite element analysis (FEA) of JMAG Designer v.20.1.","Title: A Novel Dual Rotor Permanent Magnet Flux Switching Generator for Counter Rotating Wind Turbine Applications\nYear: 2022\n\nAbstract: In this paper counter rotating (CR) dual rotor permanent magnet flux switching generator (CR-DRPMFSG) is designed and relatively studied with co- rotating DRPMFSG (CoR-DRPMFSG) for wind turbine applications. The developed CR- DRPMFSG and CoR-DRPMFSG share same stator linked with flux bridge which provide flux route. A comprehensive relative assessment of both CR- DRPMFSG and CoR-DRPMFSG are presented with static attributes, over-load, and over-speed capability for generating output voltage, output current, output power, power density, losses, and efficiency. Comparative study with static characteristics illustrates that developed CR- DRPMFSG shows 34.34% elevated phase flux which improve output power, cumulative output torque is improved by 23.86%, and suppressed cogging torque by 66.87% at CoR-DRPMFSG that results lower pulsation in instantaneous torque. Furthermore, a detailed performance analysis is investigated with different number of armature winding turns per phase and combined over-load and over-speed capability. Study discloses that in contrast with CoR-DRPMFSG, counterpart CR- DRPMFSG offer 27.17% higher output power that results 1.25 times power density with a good voltage regulation factor of 18.67%. In additional, despite of 2.27% improvement of efficiency in case of phase winding turns analysis and 4.81% increase in over-load and over-speed capability, contour efficiency map unveils that CR- DRPMFSG offer wide range of higher efficiency operating region during over-load and over-speed condition accompany with stable voltage profile with load variation.","Title: Development of a Low-Cost Modular Structure Fault Tolerant Field Excited Flux Switching Linear Machine for Urban Rail Transit\nYear: 2021\n\nAbstract: This paper proposes double sided complementary modular field excited flux switching linear machine (FEFSLM). FEFSLM offers the low cost, variable flux capability for a wide speed range, a compact and robust stator which is suitable for the long stroke application. Compared to other linear machines, complementary modular design has more sinusoidal and symmetrical flux linkage and lower detent force. Initially, the topology and machine working principle is thoroughly discussed. To maximize the thrust force of the machine and optimize the geometric parameters, built-in genetic algorithm (GA) of JMAG ver. 20 is utilized. Furthermore, the modular design incorporates the concept of fault-tolerant capabilities to provide the required decoupling between phases. 2D finite element analysis (FEA) is used to analyze the machine performance. Comparatively the optimized design exhibits higher thrust force, lower thrust force ripples and higher efficiency than the initial design.","Title: Design synthesis and optimization of a 4-SPS intrinsically compliant parallel wrist rehabilitation robotic orthosis\nYear: 2021\n\nAbstract: Neuroplasticity allows the human nervous system to adapt and relearn motor control following stroke. Rehabilitation therapy, which enhances neuroplasticity, can be made more effective if assisted by robotic tools. In this paper, a novel 4-SPS parallel robot has been developed to provide recovery of wrist movements post-stroke. The novel mechanism presented here was inspired by the forearm anatomy and can provide the rotational degrees of freedom required for all wrist movements. The robot design has been discussed in detail along with the necessary constructional, kinematic, and static analyses. The spatial workspace of the robot is estimated considering various dimensional and application-specific constraints besides checking for singular configurations. The wrist robot has been further evaluated using important performance indices such as condition number, actuator forces, and stiffness. The pneumatic artificial muscles exhibit varying stiffness, and therefore, workspace points are reached with different overall stiffness of the robot. It is essential to assess robot workspace points that can be reached with positive forces in actuators while maintaining a positive definite overall stiffness matrix. After the above analysis, design optimization has been carried out using an evolutionary algorithm whereby three critical criteria are optimized simultaneously for optimal wrist robot design.","Title: Threshold-Based Analysis of the Code Quality of High-Performance Computing Software Packages\nYear: 2020\n\nAbstract: Many popular metrics used for the quantification of the quality or complexity of a codebase (e.g. cyclomatic complexity) were developed in the 1970s or 1980s when source code sizes were significantly smaller than they are today, and before a number of modern programming language features were introduced in different languages. Thus, the many thresholds that were suggested by researchers for decidi...","Title: Consequences of Flux Gap on Intriguing Features of Modular Stator Inset Permanent Magnet Consequent Pole Synchronous Machine\nYear: 2022\n\nAbstract: In this paper a novel Inset Permanent Magnet Consequent Pole Synchronous Machine (IPMCPSM) with H-type modular stator core for higher average torque (T-alpha), torque density (T-d), power density (P-d) and efficiency (eta) with features of reduced torque ripple ratio (T-r) and harmonics content in back-EMF (EMFTHD) are proposed. Detailed static analysis of the proposed IPMCPSM under variable flux gaps at all and alternate stator teeth is investigated. Performance analyses disclose that with variable flux gaps in proposed IPMCPSM, beside improved flux weakening capability due to flux focusing effects, electromagnetic performance is greatly improved. Additionally, due to physical isolation of the adjacent phase modules with modular topology, mutual flux influence is de-coupled that improve phase self-inductance to mitigate the short-circuited current under fault condition whereas mutual flux decoupling mitigates mutual inductance that ultimately improves overall machine fault-tolerant capability. Furthermore, effectiveness of the proposed IPMCPSM with H-type modular stator is elaborated with comparative study of conventional E-core and C-core topologies. Detailed comparative analysis reveals that proposed IPMCPSM suppresses EMFTHD, improve eta by 18.9%, diminish T-r up to 55% and boost T-alpha and P-d maximum up to 2.66, 2.59 times, respectively with enhanced flux focusing effects and fault tolerant capability.","Title: Porosity, mass and geometric imperfection sensitivity in coupled vibration characteristics of CNT-strengthened beams with different boundary conditions\nYear: 2022\n\nAbstract: Structures face different types of imperfections and defects during the fabrication process, installation and working environment. In this paper, the imperfection effects in the coupled vibration behaviour of axially functionally graded carbon nanotube (CNT)-strengthened beam structures with different boundary conditions are analysed considering porosity as well as geometric and mass imperfections in the structure. Porosity is modelled using different types of formulations for simple-cell, open-cell and closed-cell porous structures. The porosity is assumed to be either uniform or by varying through the thickness of the hollow beam using different functions. Mass imperfection effect is added to the system by considering a concentrated mass in the system affecting the mass homogeneity of the structure. Geometry imperfection is also considered by having an initial deformation in the structure which could be caused by an improper fabrication process. Coupled axial and transverse equations of motion are obtained using Hamilton’s principle and the von Kármán geometrical nonlinearity. Governing equations are solved for different types of boundary conditions using a semi-analytical modal decomposition technique. It is shown that strengthening the base matrix with CNT fibres can improve the vibration behaviour of imperfect structures and the influence of CNT volume fraction and distribution through the length of the beam is discussed. The results provided in this paper may be used as a benchmark to validate future experimental results to prevent imperfection, delamination and stress singularities in the structures.","Title: Analytical Modeling of Novel High Thrust Force Density Segmented PM Consequent Pole Linear Flux Switching Machine\nYear: 2022\n\nAbstract: Permanent Magnet Linear Flux Switching Machines (PMLFSMs) are potential candidates when higher thrust force (T-F) and low cost are the primal requirements. However, conventional PMLFSMs shows flux leakages and utilizes high Permanent Magnet (PM) volume (V-PM) that increase overall expense. Therefore, this paper proposed novel Segmented PM Consequent Pole Linear Flux Switching Machine (SPMCPLFSM) with flux bridges. In comparison with PMLFSM, the proposed SPMCPLFSM diminish detent force by 20.41%, suppress thrust force ripples by 27.68%, reduces ripple ratio by 1.77 times, improve T-F to 2 times and boost T-F density to 2.64 times utilizing 75% PM volume and reducing PM cost by 24.16%. Moreover, to overcome computational complexity and computation time, analytical model uniting Lumped Parametric Magnetic Equivalent Circuits, vector potential and Maxwell Stress Tensor method are utilized for open circuit flux linkages, magnetic flux density, detent force and thrust force. Finally, analytical model is validated with finite element analysis (FEA) that show good agreement with FEA. Thus, authors are assured to suggest analytical techniques for early design purpose and proposed SPMCPLFSM for roller coaster application.","Title: A two-layer decentralized charging approach for residential electric vehicles based on fuzzy data fusion\nYear: 2022\n\nAbstract: This work presents a two-layer decentralized charging approach (TLDCA) based on fuzzy data fusion concerning the economic and power layers for optimizing the charging cost of residential electric vehicles (EVs). We defined the problem with the fuzzy objective function of minimizing the charging costs and presented a detailed fuzzy integer linear programming formulation for obtaining the optimal solution set. The optimal solution set relies on the decision control variable which is obtained through the fuzzy fusion mechanism that incorporates multiple independent and uncertain day-ahead price patterns and state-of-charge inputs from the utility grid and EV domains. The developed TLDCA reduces the charging cost for EVs while guaranteeing their required energy by determining the optimal charging schedule. We conduct two case studies to investigate the TLDCA behavior, where the first case explores the optimization of charging costs and the changing needs of individual EVs. The second case examines the charging cost, impact on load profile, and peak-to-average ratio against the summer and winter load profiles for the aggregated EVs. The simulation results verify that the developed TLDCA optimizes the charging cost and peak-to-average ratio compared to the uncoordinated charging, standard-rate charging, and time-of-use charging schemes."],"string":"[\n \"Title: Sequential Optimization Of Paths In Directed Graphs Relative To Different Cost Functions\\nYear: 2011\\n\\nAbstract: This paper is devoted to the consideration of an algorithm for sequential optimization of paths in directed graphs relative to different cost functions. The considered algorithm is based on an extension of dynamic programming which allows to represent the initial set of paths and the set of optimal paths after each application of optimization procedure in the form of a directed acyclic graph.\",\n \"Title: Sequential optimization of matrix chain multiplication relative to different cost functions\\nYear: 2011\\n\\nAbstract: In this paper, we present a methodology to optimize matrix chain multiplication sequentially relative to different cost functions such as total number of scalar multiplications, communication overhead in a multiprocessor environment, etc. For n matrices our optimization procedure requires O(n3) arithmetic operations per one cost function. This work is done in the framework of a dynamic programming extension that allows sequential optimization relative to different criteria.\",\n \"Title: Effect of Cadence Regulation on Muscle Activation Patterns During Robot-Assisted Gait: A Dynamic Simulation Study.\\nYear: 2013\\n\\nAbstract: Cadence or stride frequency is an important parameter being controlled in gait training of neurologically impaired subjects. The aim of this study was to examine the effects of cadence variation on muscle activation patterns during robot-assisted unimpaired gait using dynamic simulations. A 2-D musculoskeletal model of human gait was developed considering eight major muscle groups along with an existing ground contact force model. A 2-D model of a robotic orthosis was also developed that provides actuation to the hip, knee, and ankle joints in the sagittal plane to guide subject's limbs on reference trajectories. A custom inverse dynamics algorithm was used along with a quadratic minimization algorithm to obtain a feasible set of muscle activation patterns. Predicted patterns of muscle activations during slow, natural, and fast cadence were compared and the mean muscle activations were found to be increasing with an increase in cadence. The proposed dynamic simulation provides important insight into the muscle activation variations with change in cadence during robot-assisted gait and provides the basis for investigating the influence of cadence regulation on neuromuscular parameters of interest during robot-assisted gait.\",\n \"Title: Optimization And Analysis Of Decision Trees And Rules: Dynamic Programming Approach\\nYear: 2013\\n\\nAbstract: This paper is devoted to the consideration of software system Dagger created in KAUST. This system is based on extensions of dynamic programming. It allows sequential optimization of decision trees and rules relative to different cost functions, derivation of relationships between two cost functions (in particular, between number of misclassifications and depth of decision trees), and between cost and uncertainty of decision trees. We describe features of Dagger and consider examples of this system's work on decision tables from UCI Machine Learning Repository. We also use Dagger to compare 16 different greedy algorithms for decision tree construction.\",\n \"Title: Sequential optimization of binary search trees for multiple cost functions\\nYear: 2011\\n\\nAbstract: In this paper, we present a methodology to model the optimal binary search tree problem as a directed acyclic graph to extract all possible optimal solutions. We provide a mechanism to find optimal binary search trees relative to different types of cost functions, sequentially. We prove that for a set of n keys our optimization procedure makes O(n3) arithmetic operations per cost function such as weighted depth or average weighted depth.\",\n \"Title: Automatic Vehicle Checking Agent (VCA)\\nYear: 2011\\n\\nAbstract: A definition of intelligence is given in terms of performance that can be quantitatively measured. In this study, we have presented a conceptual model of Intelligent Agent System for Automatic Vehicle Checking Agent (VCA). To achieve this goal, we have introduced several kinds of agents that exhibit intelligent features. These are the Management agent, internal agent, External Agent, Watcher agent and Report agent. Metrics and measurements are suggested for evaluating the performance of Automatic Vehicle Checking Agent (VCA). Calibrate data and test facilities are suggested to facilitate the development of intelligent systems.\",\n \"Title: Adaptive impedance control of a robotic orthosis for gait rehabilitation.\\nYear: 2013\\n\\nAbstract: Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis w...\",\n \"Title: Control of a robotic orthosis for gait rehabilitation\\nYear: 2013\\n\\nAbstract: Robot assisted gait training may help in producing rapid improvements in functional gait parameters. This paper presents new experimental results with an intrinsically compliant robotic gait training orthosis. The newly developed robotic orthosis has 6 degrees of freedom (DOFs). A trajectory tracking controller based on the boundary layer augmented sliding control (BASMC) law was implemented to guide the subject's limbs on physiological gait trajectories. The compliance of the robotic orthosis sagittal plane hip and knee joints was also controlled, independently of the trajectory tracking control. The robotic orthosis and the control scheme were evaluated on three neurologically intact subjects walking on a treadmill. A maximum trajectory tracking error of 10^o was recorded at the hip and knee sagittal plane joints. The results showed that subjects can walk in the robotic orthosis with comfort and the BASMC law was able to guide the subject's limbs on reference physiological trajectories.\",\n \"Title: Totally Optimal Decision Trees for Monotone Boolean Functions with at Most Five Variables.\\nYear: 2013\\n\\nAbstract: In this paper, we present the empirical results for relationships between time (depth) and space (number of nodes) complexity of decision trees computing monotone Boolean functions, with at most five variables. We use Dagger (a tool for optimization of decision trees and decision rules) to conduct experiments. We show that, for each monotone Boolean function with at most five variables, there exists a totally optimal decision tree which is optimal with respect to both depth and number of nodes.\",\n \"Title: Learning hereditary and reductive prolog programs from entailment\\nYear: 2009\\n\\nAbstract: In this paper we study exact learning of Prolog programs from entailment and present an algorithm to learn two rich classes of Prolog programs namely hereditary and reductive Prolog programs. These classes contain standard Prolog programs with and without recursion like append, merge, split, delete, member, prefix, suffix, length, add, etc. Additionally our algorithm learns the hereditary Prolog programs in polynomial time.\",\n \"Title: A Step towards Software Corrective Maintenance Using RCM model\\nYear: 2009\\n\\nAbstract: From the preliminary stage of software engineering, selection of appropriate\\nenforcement of standards remained a challenge for stakeholders during entire\\ncycle of software development, but it can lead to reduce the efforts desired\\nfor software maintenance phase. Corrective maintenance is the reactive\\nmodification of a software product performed after delivery to correct\\ndiscovered faults. Studies conducted by different researchers reveal that\\napproximately 50 to 75 percent of the effort is spent on maintenance, out of\\nwhich about 17 to 21 percent is exercised on corrective maintenance. In this\\npaper, authors proposed a RCM (Reduce Corrective Maintenance) model which\\nrepresents the implementation process of number of checklists to guide the\\nstakeholders of all phases of software development. These check lists will be\\nfilled by corresponding stake holder of all phases before its start. More\\nprecise usage of the check list in relevant phase ensures successful\\nenforcement of analysis, design, coding and testing standards for reducing\\nerrors in operation stage. Moreover authors represent the step by step\\nintegration of checklists in software development life cycle through RCM model.\",\n \"Title: The Proper Role of Agents in Future Resilient Smart Grids.\\nYear: 2014\\n\\nAbstract: Smart Grids are in focus of several international R&D past and present efforts since at least a decade. Smart Grids is a well-known metaphor for future power grids. However, the meaning, or semantics of the concept has, naturally, changed due to increased understanding of the inherent complexities of the subject matter. The driving forces behind the efforts on Smart Grids include: Demands of integrating new energy sources such as Distributed Energy Resources (DER) and Renewable Energy Resources (RES) in a massive way into generation, transmission and distribution of future energy systems. Establishment of a de-regulated customer oriented energy markets, including new types of energy based service markets. Design and implementation of resilient and trustworthy services coordinating and monitoring use-case dependent sets of stakeholders during operations. The transition from today's mostly hierarchical power grids towards tomorrow's Smart Grids poses several challenges to be properly addressed and harnessed. We argue that proper use of agent technologies is a key technology towards this end. Furthermore, we argue that design and implementation of Smart Grids have to be supported by Configurable Experiment Platforms to carter for the under specifications of such systems. Resilience of systems has several aspects. We focus on resilience related to different kinds of cyber attacks and self-healing.\",\n \"Title: Dynamic modeling of pneumatic muscles using modified fuzzy inference mechanism\\nYear: 2009\\n\\nAbstract: Pneumatic muscle actuators (PMA), owing to their obvious advantages over conventional linear actuators and pneumatic cylinders, have been recently used in the medical and industrial robotic applications. However, their potential has not been fully exploited due to their highly nonlinear and time dependent behavior. An attempt is being made in the proposed work to accurately predict the uncertain and ambiguous characteristics of PMA. It was revealed from a scrupulous review of the previous work that conventional tools such as analytical and numerical methods can model a nonlinear system but the time dependent behavior cannot be accurately modeled. In the present research, Artificial Intelligence (AI) based techniques such as Neural Network (NN) and Fuzzy Inference System (FIS) have been used and their results are analyzed. It was found that FIS based on Takagi-Sugeno-Kang inference mechanism provides better accuracy and can model the time dependency of PMA. However, to achieve higher accuracy from the Fuzzy model, its parameters are required to be optimized. Three different approaches, namely, gradient descent method (GD), genetic algorithms (GA) and Modified Genetic Algorithm (MGA) have been used to identify the fuzzy parameters. Results clearly illustrate the improved prediction performance of the MGA based fuzzy inference system. Compared to the previous research in dynamic modeling of PMA, the proposed fuzzy inference system is found to provide better prediction accuracy.\",\n \"Title: Relationships between depth and number of misclassifications for decision trees\\nYear: 2011\\n\\nAbstract: This paper describes a new tool for the study of relationships between depth and number of misclassifications for decision trees. In addition to the algorithm the paper also presents the results of experiments with three datasets from UCI Machine Learning Repository [3].\",\n \"Title: Improvement in RUP Project Management via Service Monitoring: Best Practice of SOA\\nYear: 2010\\n\\nAbstract: Management of project planning, monitoring, scheduling, estimation and risk\\nmanagement are critical issues faced by a project manager during development\\nlife cycle of software. In RUP, project management is considered as core\\ndiscipline whose activities are carried in all phases during development of\\nsoftware products. On other side service monitoring is considered as best\\npractice of SOA which leads to availability, auditing, debugging and tracing\\nprocess. In this paper, authors define a strategy to incorporate the service\\nmonitoring of SOA into RUP to improve the artifacts of project management\\nactivities. Moreover, the authors define the rules to implement the features of\\nservice monitoring, which help the project manager to carry on activities in\\nwell define manner. Proposed frame work is implemented on RB (Resuming Bank)\\napplication and obtained improved results on PM (Project Management) work.\",\n \"Title: Smart Home Services Enabled by Service Level Agreements\\nYear: 2012\\n\\nAbstract: The challenge for the future Smart Grids is to improve the energy efficiency and enable groups of stakeholders to offer services to customers. An intelligent agent-based ICT infrastructure supplementing SCADA systems is required to support such perspectives of power grids. This paper focus on describing a novel approach, using Service Level Agreements (SLAs) as a tool, for improving coordination between high-level Smart Grid business requirements and low level infrastructure affordances. Monitoring of SLAs and trustworthy data management requires setting up and monitoring clusters of SLAs coordinating sets of relevant stakeholders. We argue that coordinating services with infrastructures using SLA, as a coordination mechanism is a promising approach towards sustainable Smart Grid solutions. A case study of agent-based comfort monitoring and control in Smart homes illustrates our approach and related tools.\",\n \"Title: Mapping of SOA and RUP: DOA as Case Study\\nYear: 2010\\n\\nAbstract: SOA (Service Oriented Architecture) is a new trend towards increasing the\\nprofit margins in an organization due to incorporating business services to\\nbusiness practices. Rational Unified Process (RUP) is a unified method planning\\nform for large business applications that provides a language for describing\\nmethod content and processes. The well defined mapping of SOA and RUP leads to\\nsuccessful completion of RUP software projects to provide services to their\\nusers. DOA (Digital Office Assistant) is a multi user SOA type application that\\nprovides appropriate viewer for each user to assist him through services. In\\nthis paper authors proposed the mapping strategy of SOA with RUP by considering\\nDOA as case study.\",\n \"Title: Relationships between Average Depth and Number of Misclassifications for Decision Trees\\nYear: 2014\\n\\nAbstract: This paper presents a new tool for the study of relationships between the total path length or the average depth and the number of misclassifications for decision trees. In addition to algorithm, the paper also presents the results of experiments with datasets from UCI ML Repository [9] and datasets representing Boolean functions with 10 variables.\",\n \"Title: Mapping The Best Practices of XP and Project Management: Well defined approach for Project Manager\\nYear: 2010\\n\\nAbstract: Software engineering is one of the most recent additions in various\\ndisciplines of system engineering. It has emerged as a key obedience of system\\nengineering in a quick succession of time. Various Software Engineering\\napproaches are followed in order to produce comprehensive software solutions of\\naffordable cost with reasonable delivery timeframe with less uncertainty. All\\nthese objectives are only satisfied when project's status is properly monitored\\nand controlled; eXtreme Programming (XP) uses the best practices of AGILE\\nmethodology and helps in development of small size software very sharply. In\\nthis paper, authors proposed that via XP, high quality software with less\\nuncertainty and under estimated cost can be developed due to proper monitoring\\nand controlling of project. Moreover, authors give guidelines that how\\nactivities of project management can be embedded into development life cycle of\\nXP to enhance the quality of software products and reduce the uncertainty.\",\n \"Title: Diagnosis of constant faults in iteration-free circuits over monotone basis.\\nYear: 2014\\n\\nAbstract: We show that for each iteration-free combinatorial circuit S over a basis B containing only monotone Boolean functions with at most five variables, there exists a decision tree for diagnosis of constant faults on inputs of gates with depth at most 7 L ( S ) where L ( S ) is the number of gates in S .\",\n \"Title: Diagnosis of constant faults in read-once contact networks over finite bases.\\nYear: 2015\\n\\nAbstract: We study the depth of decision trees for diagnosis of constant 0 and 1 faults in read-once contact networks over finite bases containing only indecomposable networks. For each basis, we obtain a linear upper bound on the minimum depth of decision trees depending on the number of edges in the networks. For bases containing networks with at most 10 edges we find coefficients for linear bounds which are close to sharp.\",\n \"Title: Total Path Length and Number of Terminal Nodes for Decision Trees.\\nYear: 2014\\n\\nAbstract: This paper presents a new tool for study of relationships between total path length (average depth) and number of terminal nodes for decision trees. These relationships are important from the point of view of optimization of decision trees. In this particular case of total path length and number of terminal nodes, the relationships between these two cost functions are closely related with space-time trade-off. In addition to algorithm to compute the relationships, the paper also presents results of experiments with datasets from UCI ML Repository1. These experiments show how two cost functions behave for a given decision table and the resulting plots show the Pareto frontier or Pareto set of optimal points. Furthermore, in some cases this Pareto frontier is a singleton showing the total optimality of decision trees for the given decision table.\",\n \"Title: SLA conceptual framework for coordinating and monitoring information flow in Smart Grid\\nYear: 2014\\n\\nAbstract: The EU challenges for the future energy systems will change the scene of the energy systems in Europe. A transition from centralized controlled power network to customer oriented Smart Grid operating in distributed and deregulated energy market poses several regulatory, organizational and technical challenges. In such a market scenarios, multiple stakeholders provide services to produce and deliver energy. Due to the inclusion of new stakeholders at multiple levels there is a lack of purposeful monitoring based on pre-negotiated SLAs. Hence, there exists a gap to actively monitor KPIs values among all negotiated SLAs (Service Level Agreements). This paper addresses SLA based active monitoring of information flow. The proposed SLA framework provides monitoring based on negotiated KPIs in an automated and trustworthy way to coordinate information flow. In the end a use case is presented to validate the SLA framework.\",\n \"Title: Multilayer communication network architecture for wind power farm\\nYear: 2014\\n\\nAbstract: Wind is a sustainable renewable energy source, which has recently gained high popularity among the renewable energy sources. The high maintenance and repair cost of wind turbine needs real-time monitoring and control through networks. Network communication infrastructures play important roles for the real-time monitoring and control of wind power farms because these farms are located at remote and harsh environment sites. This paper proposes multilayer communication network architecture for monitoring and controlling of wind power farms which consists of wind power farm layer, local control center layer, regional control center layer, central control center layer and neighbor control center layer. Based on the logical node concept of IEC 61400-25 standard, wind turbine is modeled and simulated by four different information including analogue measurements, status information, protection and control information, and meteorological mast information through OPNET modular. The performance of the proposed network architecture is evaluated in terms of link bandwidth and latency.\",\n \"Title: Greedy heuristics for minimization of number of terminal nodes in decision trees\\nYear: 2014\\n\\nAbstract: This paper describes, in detail, several greedy heuristics for construction of decision trees. We study the number of terminal nodes of decision trees, which is closely related with the cardinality of the set of rules corresponding to the tree. We compare these heuristics empirically for two different types of datasets (datasets acquired from UCI ML Repository and randomly generated data) as well as compare with the optimal results obtained using dynamic programming method.\",\n \"Title: Robust Nonlinear Control of an Intrinsically Compliant Robotic Gait Training Orthosis\\nYear: 2013\\n\\nAbstract: Robot-assisted gait therapy is an emerging rehabilitation practice. This paper presents new experimental results with an intrinsically compliant robotic gait training orthosis and a trajectory tracking controller. The intrinsically compliant robotic orthosis has six degrees of freedom. Sagittal plane hip and knee joints were powered by the actuation of pneumatic muscle actuators in opposing pair configuration. The orthosis has passive hip abduction/adduction joint and passive mechanisms to allow vertical and lateral translations of the trunk. A passive foot lifter having a spring mechanism was used to ensure sufficient dorsiflexion during swing phase. A trajectory tracking controller based on a chattering-free robust variable structure control law was implemented in joint space to guide the subject's limbs on physiological gait trajectories. The performance of the robotic orthosis was evaluated during two gait training modes, namely, “trajectory tracking mode with maximum compliance” and “trajectory tracking mode with minimum compliance.” The experimental evaluations were carried out with ten neurologically intact subjects. The results show that the robotic orthosis is able to perform the gait training task during the two gait training modes. All the subjects tend to deviate from the reference joint angle trajectories with an increase in robotic compliance as the subjects have more freedom to voluntarily drive the robotic orthosis.\",\n \"Title: Service level agreement: Coordination and monitoring of actors in Smart Grid\\nYear: 2012\\n\\nAbstract: Smooth and reliable operation of the future Smart Grid requires addressing coordination and interoperability issues. In Smart Grid, the coordination of new actors and monitoring of new business processes, such as Active Demand and Electric Vehicles is non-trivial. These new actors and related business processes change the landscape of power grid from traditional passive Demand Side Management of loads to active customers connected in Active Distribution Grid. Smart Grid operations require monitoring and coordination between high-level business requirements and low-level infrastructure affordances. To support such perspectives of the power grid an additional ICT infrastructure supplementing traditional SCADA systems is required. We argue that to enable and validate end-to-end interoperable solutions a new tool is required. In this paper we introduce Service Level Agreement as one such a tool, supporting design and implementation of well-coordinated interoperable information flows and ensuring shared agreed-upon situation awareness among stakeholders. Finally we illustrate our approach in Smart Grid Electric Vehicle systems.\",\n \"Title: Multicriteria Design Optimization of a Parallel Ankle Rehabilitation Robot: Fuzzy Dominated Sorting Evolutionary Algorithm Approach.\\nYear: 2016\\n\\nAbstract: Parallel robots, owing to their increased stiffness, accuracy, and compactness, are preferred over their serial counterparts in applications involving higher torques and precision such as robot-assisted physical therapy. However, their design is complex and calls for obtaining a tradeoff between several conflicting objectives such as the minimization of actuator forces versus the maximization of workspace while maintaining a close to unity condition number, etc. While evolutionary algorithms have been proposed in the literature for simultaneous optimization of many objectives, they have been found to be inefficient in dealing with a large number of objectives. We propose a fuzzy logic-based sorting approach in this paper which effectively replaces the concept of nondominated sorting and provides a better discrimination between solutions and clear termination logic. The proposed sorting algorithm has been evaluated against the existing nondominated sorting genetic algorithm II in the pretext of design optimization of a parallel ankle rehabilitation robot. The proposed fuzzy-based approach is able to provide a better discrimination among solutions and, thereby an improved parallel ankle robot design.\",\n \"Title: Three-Stage Design Analysis and Multicriteria Optimization of a Parallel Ankle Rehabilitation Robot Using Genetic Algorithm\\nYear: 2015\\n\\nAbstract: This paper describes the design analysis and optimization of a novel 3-degrees of freedom (DOF) wearable parallel robot developed for ankle rehabilitation treatments. To address the challenges arising from the use of a parallel mechanism, flexible actuators, and the constraints imposed by the ankle rehabilitation treatment, a complete robot design analysis is performed. Three design stages of the ...\",\n \"Title: Effects of Geographical, Socio-cultural and Temporal distances on communication in Global Software Development during Requirements Change Management A Pilot Study\\nYear: 2015\\n\\nAbstract: Trend of software development is changing rapidly most of the software development organizations are trying to globalize their activities throughout the world. This trend leads towards a phenomenon called Global Software Development (GSD). The main reason behind the software globalization is its various benefits. Besides these benefits, software organizations are facing various challenges. One of these challenges is communication which is considered a big challenge in GSD and it becomes more complicated during the Requirements Change Management (RCM) process due to three factors, they are Geographical, Socio-cultural and Temporal distances. This paper presents a framework which shows the effect of these factors on communication during RCM process in GSD. Communication is the core function of collaboration which allows information to be exchanged between the team members. A pilot study has been conducted in three GSD organizations. A quantitative research method has been used to collect data. The findings from the survey data show that these three factors have a strong negative impact on communication process in GSD.\",\n \"Title: Performance Evaluation of Ensemble Methods For Software Fault Prediction: An Experiment.\\nYear: 2015\\n\\nAbstract: In object-oriented software development, a plethora of studies have been carried out to present the application of machine learning algorithms for fault prediction. Furthermore, it has been empirically validated that an ensemble method can improve classification performance as compared to a single classifier. But, due to the inherent differences among machine learning and data mining approaches, the classification performance of ensemble methods will be varied. In this study, we investigated and evaluated the performance of different ensemble methods with itself and base-level classifiers, in predicting the faults proneness classes. Subsequently, we used three ensemble methods AdaboostM1, Vote and StackingC with five base-level classifiers namely Naivebayes, Logistic, J48, VotedPerceptron and SMO in Weka tool. In order to evaluate the performance of ensemble methods, we retrieved twelve datasets of open source projects from PROMISE repository. In this experiment, we used k-fold (k=10) cross-validation and ROC analysis for validation. Besides, we used recall, precision, accuracy, F-value measures to evaluate the performance of ensemble methods and base-level Classifiers. Finally, we observed significant performance improvement of applying ensemble methods as compared to its base-level classifier, and among ensemble methods we observed StackingC outperformed other selected ensemble methods for software fault prediction.\",\n \"Title: Impedance Control of an Intrinsically Compliant Parallel Ankle Rehabilitation Robot.\\nYear: 2016\\n\\nAbstract: Robot-aided physical therapy should encourage subject's voluntary participation to achieve rapid motor function recovery. In order to enhance subject's cooperation during training sessions, the robot should allow deviation in the prescribed path depending on the subject's modified limb motions subsequent to the disability. In the present work, an interactive training paradigm based on the impedanc...\",\n \"Title: Design optimization of a cable actuated parallel ankle rehabilitation robot: A fuzzy based multi-objective evolutionary approach.\\nYear: 2016\\n\\nAbstract: Robotic devices can be potentially used to assist physical therapy treatments in order to restore musculoskeletal system malfunctions owing to neurological disorders. Cable actuated parallel robots, despite their obvious benefits such as enhanced workspace, light weight, and flexibility, are not popularly used in ankle rehabilitation treatments, due to their complex mechanism and cable actuation issues. In order to address these issues, it is recommended to carry out robot design optimization. However, design synthesis of the cable actuated parallel ankle robot calls for multi-objective optimization (MOO), since there are multiple and conflicting objectives to achieve. To acquire more choices between actuator forces, overall stiffness of robot (which is crucial for a cable based ankle robot) and other vital design objectives, it is required to explore the extreme ends of the Pareto Front (PF) more carefully. Existing multi-objective evolutionary algorithms (MOEAs) normally focus on the convergence and may not provide solutions at the extremities of PF. Capitalizing on this improvement opportunity, this paper presents a fuzzy based MOEA, namely, biased fuzzy sorting genetic algorithm (BFSGA) which encourages solutions in the extreme zones of the PF. It is shown in this paper that using proposed method, diversity in the populations is supported and in the process wider trade-off choices of objectives can be obtained. During ankle robot design optimization, crisp objectives are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS). Subsequently OAS is used to assign a fuzzy dominance ranking to the design solutions. It is found that the BFSGA approach performs well in exploring the extreme zones of the Pareto front, which are normally overlooked by other MOEA such as NSGA-II due to their inherent mechanism.\",\n \"Title: Threshold analysis of design metrics to detect design flaws: student research abstract.\\nYear: 2016\\n\\nAbstract: Detection of design flaws at different granularity levels of software can help the software engineer to reduce the testing efforts and maintenance cost. In the context of metric-based analysis, current state of art for the quality assurance tools is to extract the metrics from the source code and analyzed the design complexity. But in case of legacy systems, a software engineer needs to pass through the re-engineering process. In this study, I propose a methodology to investigate the threshold effect of software design metrics in order to detect design flaws and its effect over the granularity level of software. Moreover, I will use some statistical methods and machine learning techniques to derive and validate the effect of thresholds over the NASA and open source datasets retrieve from the PROMISE repository.\",\n \"Title: Empirical investigation of fault predictors in context of class membership probability estimation.\\nYear: 2016\\n\\nAbstract: In the domain of software fault prediction, class membership probability of a selected classifier and the factors related to its estimation can be considered as necessary information for tester to take informed decisions about software quality issues. The objective of this study is to empirically investigate the class membership probability estimation capability of 15 classifiers/fault predictors on 12 datasets of open source projects retrieved from PROMISE repository. We empirically validate the effect of dataset characteristics and set of metrics on the performance of classifiers in estimating the class membership probability. We used Receiver Operating Characteristics-Area under Curve (ROC-AUC) value and overall accuracy as benchmarks to evaluate and compare the performance of classifiers. We apply Friedman's, post-hoc Nemenyi and Analysis of Means (ANOM) test to compare the significant performance of classifiers. We conclude that ADTree and RandomForest outperform, while ZeroR classifier cannot show significant performance for estimation of class membership probability.\",\n \"Title: A Methodology to Automate the Selection of Design Patterns\\nYear: 2016\\n\\nAbstract: Background: Over the last two decades, numerous software design patterns have been introduced and cataloged on the basis of developer's interest and skills. Motivation: In software design phase, inexperienced designers are mostly concerned on how to select an appropriate design pattern from the catalog of relevant patterns in order to solve a design problem. The existing automated design pattern selection methodologies are limited to the need of formal specification of design patterns or an appropriate sample size to make the learning process more effective. Method: To address this concern, we propose a three step methodology to automate the selection process of design pattern for a design problem. The steps of the methodology are text preprocessing, use of an unsupervised learning technique (that is Fuzzy c-Mean) as a core function to quantitatively determine the resemblance of different objects and selection of most appropriate pattern for a design problem. We evaluate our methodology with two samples that is Gang-of-Four (GoF) design pattern and spoiled pattern collection, and three object-oriented related design problems. Moreover, we used Fuzzy Silhouette test, Kappa (k) test, Cosine Similarity and argmax function to measure the effectiveness of our methodology. Results: In case of GoF pattern collection, we validated the reliability of Fuzzy c-Mean (FCM) results using a classification decision tree, and observed promising results compared to other automation techniques. Conclusion: From the comparison results, we observed 11%, 4% and 18% improvement in the performance of proposed technique as compared to supervised learning techniques of Support Vector Machine, Naïve Bayes and C4.5 respectively.\",\n \"Title: A Boundary Property For Upper Domination\\nYear: 2016\\n\\nAbstract: An upper dominating set in a graph is a minimal (with respect to set inclusion) dominating set of maximum cardinality. The problem of finding an upper dominating set is generally NP-hard, but can be solved in polynomial time in some restricted graph classes, such as P-4- free graphs or 2K(2)-free graphs. For classes defined by finitely many forbidden induced subgraphs, the boundary separating difficult instances of the problem from polynomially solvable ones consists of the so called boundary classes. However, none of such classes has been identified so far for the upper dominating set problem. In the present paper, we discover the first boundary class for this problem.\",\n \"Title: Totally optimal decision trees for Boolean functions.\\nYear: 2016\\n\\nAbstract: We study decision trees which are totally optimal relative to different sets of complexity parameters for Boolean functions. A totally optimal tree is an optimal tree relative to each parameter from the set simultaneously. We consider the parameters characterizing both time (in the worst- and average-case) and space complexity of decision trees, i.e., depth, total path length (average depth), and number of nodes. We have created tools based on extensions of dynamic programming to study totally optimal trees. These tools are applicable to both exact and approximate decision trees, and allow us to make multi-stage optimization of decision trees relative to different parameters and to count the number of optimal trees. Based on the experimental results we have formulated the following hypotheses (and subsequently proved): for almost all Boolean functions there exist totally optimal decision trees (i) relative to the depth and number of nodes, and (ii) relative to the depth and average depth.\",\n \"Title: Upper Domination: towards a dichotomy through boundary properties.\\nYear: 2018\\n\\nAbstract: An upper dominating set in a graph is a minimal dominating set of maximum cardinality. The problem of finding an upper dominating set is generally NP-hard. We study the complexity of this problem in finitely defined classes of graphs and conjecture that the problem admits a complexity dichotomy in this family. A helpful tool to study the complexity of an algorithmic problem is the notion of boundary classes. However, none of such classes has been identified so far for the upper dominating set problem. We discover the first boundary class for this problem and prove the dichotomy for monogenic classes.\",\n \"Title: Detection of Fault-Prone Classes Using Logistic Regression Based Object-Oriented Metrics Thresholds\\nYear: 2016\\n\\nAbstract: Background: In the plethora of studies, the object-orientedmetrics have been empirically validated to assess the design properties and quantify the high-level quality attributes such as fault-proneness, either at the method or class granularity levels of software. Motivation: A more precise value of an object-oriented metric can be used as an indicator for the developers tomake the informed decisions regarding the detection of design flaws and classify the fault-proneness classes. Method: Bender used an approach in the domain of epidemiology studies to derivethe threshold values for the risk factors. In our study, we follow the Bender's approach and propose a model to derive the thresholds for a set of software design metrics via non-linearfunctions, which are described through logistic regressioncoefficients. Subsequently, we perform four types of analysis and three experiments in order to evaluate and compare the effectiveness of derived thresholds in the domain of classificationof fault proneness classes. We use the Precision, Recall, Fmeasureand classification accuracy performance measures toassess the effectiveness of derived metrics thresholds. Results: We compare the derive threshold values of DIT, CA, LCOM andNPM metrics with their existing data distribution basedthreshold values, and observed the significant increase in the classification accuracy of fault-prone classes. For example, DIT(27%), Ca (2%), NPM (2%) and LCOM (15%) for the Ant-1.5project. Conclusion: The analysis results suggest that the proposed model can be applied to derive the thresholds of otherobject-oriented metrics which present either with or withoutheavy-tailed distribution, however, the proposed model to derivethresholds cannot generalize for all the systems due to variationin data characteristics.\",\n \"Title: Assist-as-Needed Control of an Intrinsically Compliant Robotic Gait Training Orthosis.\\nYear: 2017\\n\\nAbstract: It is a common hypothesis in the field of robot-assisted gait rehabilitation that the active involvement and voluntary participation of neurologically impaired subjects in the robotic gait training process may enhance the outcomes of such therapy. An adaptive seamless assist-as-needed (AAN) control scheme was developed for the robotic gait training. The AAN control scheme learns in real time the d...\",\n \"Title: A Framework for Ranking of Software Design Patterns.\\nYear: 2017\\n\\nAbstract: Several software design patterns have been familiarized either in canonical or as variant solutions in order to solve a problem. Novice designers mostly adopt patterns without considering their ground reality and relevancy with design problems, which may cause to increase the development and maintenance efforts. In order to realize the ground reality and to automate the selection process, the existing automated systems for the selection of design patterns either need formal specification or precise learning through training the numerous classifiers. In order to address this issue, we propose an approach on the base of a supervised learning technique named 'Learning to Rank', to rank the design patterns with respect to text similarity with the description of the given design problems. Subsequently, we also propose an evaluation model in order to assess the effectiveness of the proposed approach. We evaluate the effectiveness of the proposed approach in the context of several design pattern collections and relevant design problems. The promising experimental results indicate the applicability of the proposed approach.\",\n \"Title: A methodology to predict the instable classes: student research abstract.\\nYear: 2017\\n\\nAbstract: Class stability is intrinsically characterized by the evolution of a number of dependencies and change propagation factors used to promote the ripple effect. In this regard, historical information regarding change propagation factors can aid to identify the classes prone to ripple effect (that is instable classes). In this paper, we propose a methodology to exploit the versions history of change propagation factors in order to predict the instable classes. Initially, we have implemented the proposed methodology with version history of three open source projects MongoDB Java Driver, Google Guava and Apache MyFaces and obtained promising results as compared to existing stability assessors. Subsequently, the experimental results indicate that proposed methodology can be used to identify the classes prone to ripple effect and can aid developers to reduce the efforts needed to maintain and evolve the system.\",\n \"Title: Towards a hypothetical framework of humans related success factors for process improvement in global software development: systematic review.\\nYear: 2017\\n\\nAbstract: Presently, the majority of the software development organizations are adopting the phenomena of Global Software Development (GSD), mainly because of the significant return on investment it produces. However, GSD is a complex phenomenon and there are many challenges associated with it, especially that related to Software Process Improvement (SPI). The aim of this work is to identify humans' related factors that can positively impact the SPI process in GSD organizations and proposed a hypothetical framework of the identified success factors in relation to SPI implementation. We have adopted the Systematic Literature Review (SLR) method in order to identify the success factors. Using the SLR approach, total ten success factors were identified. The paper also reported the Critical Success Factors (CSFs) for SPI implementation following the criteria of the factors having a frequency ≥ 50% as critical. Our results reveal that five out of ten factors are critical for SPI program. Based on the analysis of the identified success factors, we have presented a hypothetical framework that has highlighted an association between the identified success factors and the implementation of the SPI program in GSD environment.\",\n \"Title: Software design patterns classification and selection using text categorization approach.\\nYear: 2017\\n\\nAbstract: •The proposed approach aid to introduce an automated system for the classification and selection of software design patterns.•The proposed approach is exploited via Fuzzy c-means unsupervised learning technique.•We leverage an approach to introduce a new feature selection method named Ensemble-IG.•An evaluation model to assess the effectiveness of the proposed approach using three widely known design pattern collection.\",\n \"Title: The Effect of Gang-of-Four Design Patterns Usage on Design Quality Attributes\\nYear: 2017\\n\\nAbstract: Context: In the plethora of studies, it has been empirically investigated that the incidence of design pattern instances can be considered as an indicator to elaborate the software design. The developers, who have more concern with design quality, are interested to know the effect of use intensity of design patterns on the system level design quality attributes. Goal: The objective of our study is to empirically investigate the effect of the frequent use of the Gang-of-Four (GoF) design patterns on the design quality attributes. Method: We perform a case study which includes three analyses in order to investigate, 1) the existence of a correlation between design pattern usage and design quality attributes, 2) the confounding effect of system size (number of classes) on the correlation, and 3) how the change in number of employed design pattern instances affects the design quality in the subsequent releases of a system. Results: The result of this study suggests that the reusability, flexibility and understandability have a significant relationship with the employed instances of Template, Adapter-Command, Singleton and State-Strategy design patterns, however, it is affected by the confounding effect of system size. Subsequently, in the subsequent releases of an open source project named velocity, we observed the use intensity of Singleton, Adapter-Command, and State-Strategy design patterns can improve the design quality in term of reusability and flexibility attributes.\",\n \"Title: Review on Design and Control Aspects of Robotic Shoulder Rehabilitation Orthoses.\\nYear: 2017\\n\\nAbstract: Robotic rehabilitation devices are more frequently used for the physical therapy of people with upper limb weakness, which is the most common type of stroke-induced disability. Rehabilitation robots can provide customized, prolonged, intensive, and repetitive training sessions for patients with neurological impairments. In most cases, the robotic exoskeletons have to be aligned with the human join...\",\n \"Title: Improving the Quality of Software Development Process by Introducing a New Methodology-AZ-Model.\\nYear: 2018\\n\\nAbstract: Quality is the most important factor for software development as it mainly defines customer satisfaction that is directly related to the success of a software project. The software process model is used to ensure software quality, represent a variety of task settings, manage project duration, improve the process and range to execute the process understanding, and to appropriate implicit conjecture for all task settings. Several software processes models exist in software albeit with limited scope. Given this viewpoint, this paper presents a new software development life cycle model, \\\"AZ-Model,\\\" for software development by introducing new activities during software development life cycle. It overcomes the limitations of traditional models and significantly impacts the production of a quality product in a time-box. This paper also presents a comprehensive comparative study and statistical analyses to examine the significance of AZ-Model for software development.\",\n \"Title: Correlation between the Frequent Use of Gang-of-Four Design Patterns and Structural Complexity\\nYear: 2017\\n\\nAbstract: The structural complexity of design components (e.g. Classes) is proportional to design quality at the system level and is quantified via the object-oriented metrics. The frequent use of design patterns causes of too much abstraction and can increase the structural complexity of design components. Though, in our previous work, we have empirically investigated the impact of use intensity of design pattern on the system level quality attributes. However, the empirical investigation of the effect of usage of design patterns on the design properties is still required. In this regard, we conduct an empirical study and perform a case study which includes the analysis 1) the existence of a correlation between design pattern usage and design metrics, 2) the confounding effect of system size (number of classes) on the correlation, and 3) how the change in number of employed design pattern instances affects the structural complexity in the subsequent releases of a system. The result of this study suggests that structural complexity associated with aggregation, coupling, functional abstraction design properties has a significant relationship with the employed instances of Template, Adapter-Command, Singleton, and Factory Method design patterns.\",\n \"Title: Counter Measuring Conceivable Security Threats on Smart Healthcare Devices.\\nYear: 2018\\n\\nAbstract: Smart devices, the carriers of a huge amount of private, sensitive and confidential data are pervasive in today's world with innovative and enhanced functionalities. Smartphones have brought tremendous change in people's lives with the launch of a new platform of communication and an ease of access to a wide range of applications. Due to the swift increase in the users of Android smartphones and the increasing demands based on advanced ease and features, developers are working hard to achieve the needful. Easy access to certain features and applications gave rise to the powerfulness and an efficacy of various threats, risks and vulnerabilities that can victimize users' private data residing in smartphone paradigm. With the developments and enhancements in malware, for Android-based smartphones, attacks continue to occur. In this paper, we investigate one of the possibly most destructive attacks for Android, that is, screenshot attack. We have developed \\\"ScreenStealer\\\" application and explored the vulnerabilities which make Android more inclined to risks and threats. Furthermore, we evaluated capture ratio of screenshots, resources consumption and execution time to determine effectiveness, efficiency and stealthiness of such a malicious application.\",\n \"Title: Effect of Project Management in Requirements Engineering and Requirements Change Management Processes for Global Software Development.\\nYear: 2018\\n\\nAbstract: Presently, global software development (GSD) is growing very rapidly. However, it is not an easy and straightforward process. Requirements engineering (RE) and requirements change management (RCM) both are considered as very challenging activities due to demanding rich communications. Because it is necessary to address geographical and cultural differences in GSD, this requirement makes RE and RCM challenging. This paper investigates the importance of project management in RE and RCM processes. First, the frameworks with the phenomena of specialized project management are proposed for RE and RCM. Then, a survey and blind interviews of the experts are conducted to validate the proposed frameworks. Finally, statistical tools are applied to analyze the collected data. By utilizing the analyzed data, our results show the significant impacts of both frameworks (i.e., RE and RCM) in the GSD environment.\",\n \"Title: Implications of deep learning for the automation of design patterns organization.\\nYear: 2018\\n\\nAbstract: Though like other domains such as email filtering, web page classification, sentiment analysis, and author identification, the researchers have employed the text categorization approach to automate organization and selection of design patterns. However, there is a need to bridge the gap between the semantic relationship between design patterns (i.e. Documents) and the features which are used for the organization of design patterns. In this study, we propose an approach by leveraging a powerful deep learning algorithm named Deep Belief Network (DBN) which learns on the semantic representation of documents formulated in the form of feature vectors. We performed a case study in the context of a text categorization based automated system used for the classification and selection of software design patterns. In the case study, we focused on two main research objectives: 1) to empirically investigate the effect of feature sets constructed through the global filter-based feature selection methods besides the proposed approach, and 2) to evaluate the significant improvement in the classification decision (i.e. Pattern organization) of classifiers using the proposed approach. The adjustment of DBN parameters such as a number of hidden layers, nodes and iteration can aid a developer to construct a more illustrative feature set. The experimental promising results suggest the significance of the proposed approach to construct a more representative feature set and improve the classifier’s performance in terms of organization of design patterns.\",\n \"Title: An Integrated Planning Approach Towards Home Health Care, Telehealth and Patients Group Based Care.\\nYear: 2018\\n\\nAbstract: The availability of patient-centered, cost effective, and quality oriented health care is a huge task for the health care planners in every country. In this study, a Home Health Care (HHC) planning problem is introduced to integrate the resource dimensioning issues and assignment aspects with the telehealth based care and patients' group-based care services. An integer linear programming model is developed and solved through CPLEX. The main aims of the proposed model are: (i) to provide an optimal selection of locations for HHC offices, health care workers, and patients' cluster centres besides their specific assignment; (ii) to schedule the health care session for each patient or patients' group by creating a pair of HHC nurse and telehealth staff against a specific time window; and (iii) to seek the enhancement of patient satisfaction and quality of service considering the penalties for violation of patients' preferences and inappropriate experience gap between the pair of nurses. Subsequently, in order to validate the effectiveness of the proposed integration approach, we employ the Fuzzy c-means to describe the appropriate organization of the HHC offices, health care workers, and patient's data. Finally, a sensitivity analysis is performed to explore the model behavior against the variation in parameter values. The detailed analysis of the results shows the effectiveness of the proposed model and its behavior with respect to different types of cost.\",\n \"Title: Automated framework for classification and selection of software design patterns.\\nYear: 2019\\n\\nAbstract: Though, Unified Modeling Language (UML), Ontology, and Text categorization approaches have been used to automate the classification and selection of design pattern(s). However, there are certain issues such as time and effort for formal specification of new patterns, system context-awareness, and lack of knowledge which needs to be addressed. We propose a framework (i.e. Three-phase method) to discuss these issues, which can aid novice developers to organize and select the correct design pattern(s) for a given design problem in a systematic way. Subsequently, we propose an evaluation model to gauge the efficacy of the proposed framework via certain unsupervised learning techniques. We performed three case studies to describe the working procedure of the proposed framework in the context of three widely used design pattern catalogs and 103 design problems. We find the significant results of Fuzzy c-means and Partition Around Medoids (PAM) as compared to other unsupervised learning techniques. The promising results encourage the applicability of the proposed framework in terms of design patterns organization and selection with respect to a given design problem.\",\n \"Title: Evolutionary Optimization Using Equitable Fuzzy Sorting Genetic Algorithm (EFSGA).\\nYear: 2019\\n\\nAbstract: This paper presents a fuzzy dominance-based analytical sorting method as an advancement to the existing multi-objective evolutionary algorithms (MOEA). Evolutionary algorithms (EAs), on account of their sorting schemes, may not establish clear discrimination amongst solutions while solving many-objective optimization problems. Moreover, these algorithms are also criticized for issues such as uncertain termination criterion and difficulty in selecting a final solution from the set of Pareto optimal solutions for practical purposes. An alternate approach, referred here as equitable fuzzy sorting genetic algorithm (EFSGA), is proposed in this paper to address these vital issues. Objective functions are defined as fuzzy objectives and competing solutions are provided an overall activation score (OAS) based on their respective fuzzy objective values. Subsequently, OAS is used to assign an explicit fuzzy dominance ranking to these solutions for improved sorting process. Benchmark optimization problems, used as case studies, are optimized using proposed algorithm with three other prevailing methods. Performance indices are obtained to evaluate various aspects of the proposed algorithm and present a comparison with existing methods. It is shown that the EFSGA exhibits strong discrimination ability and provides unambiguous termination criterion. The proposed approach can also help user in selecting final solution from the set of Pareto optimal solutions.\",\n \"Title: Systematic Literature Reviews of Software Process Improvement: A Tertiary Study.\\nYear: 2017\\n\\nAbstract: Systematic Literature Review (SLR) is becoming a vital part of present day research in software process improvement (SPI). Nevertheless, there is no available study that provides detail review of the published software process improvement SLRs. Objective: The aim of this article is to classify the SLRs of SPI in order to identify the main research areas covered and evaluate the quality of the published SLRs. Methodology: A tertiary study was conducted to review the SLRs published by other researchers on the topic of SPI. Results: Twenty-four SLR articles were identified in the field of SPI. Results show that the quality of the selected SLRs on SPI is decreasing over the recent years. The most popular research topics are factors affecting SPI and process models. Conclusions: This study provides the review and state of the art in the context of SPI research. The results of this article would be of great interest for future SPI researchers by providing in depth understanding of various research areas in SPI. The number of process improvement SLRs is increasing and the overall quality is decreasing, which could lessen their potential impact on SPI practice. Currently, SPI literature is weak in the knowledge areas such as quality and software testing process improvement.\",\n \"Title: Bi-criteria optimization of decision trees with applications to data analysis.\\nYear: 2018\\n\\nAbstract: •Algorithms for bi-criteria optimization of decision trees are created.•We compare twenty greedy heuristics for bi-criteria optimization of decision trees.•We discover very small number of Pareto optimal points for an optimization problem.\",\n \"Title: Statistical Analysis of the Effects of Heavyweight and Lightweight Methodologies on the Six-Pointed Star Model.\\nYear: 2018\\n\\nAbstract: Traditionally, software development organizations relied on heavyweight development methodologies, such as waterfall, V-model, and others. Later, agile development methodologies known as lightweight methodologies were introduced. Many considered these to be more flexible and more effective than heavyweight methodologies. Both methodologies are equally important for a software development life cycle. The purpose of adopting software development methodologies is to optimize the process model to achieve milestones while concurrently and effectively managing time, budget, and quality. The literature review reveals that there is a lack of statistical evidence for determining the effect of both methodologies on the six-pointed star model (schedule, scope, budget, risk, resource, and quality). In this paper, statistical comparisons were performed for the effects of both methodologies on each factor of the six-pointed star model and the interdependency among factors. Numerical analyses were conducted based on survey responses collected from the experienced users of both methodologies. After examining the results of all the factors of both methodologies, it was determined that lightweight methodologies are suitable for small-scale projects and that heavyweight methodologies perform better for medium- and large-scale projects.\",\n \"Title: Systematic literature study for dimensional classification of success factors affecting process improvement in global software development: client-vendor perspective.\\nYear: 2018\\n\\nAbstract: The majority of organisations are globalising their software development activities by following the ideas of global software development (GSD). The motivation behind the adoption of GSD phenomena are the list of benefits gained by the software industry. However, there are different challenges face by the GSD organisations, particularly the issues related to software process improvement (SPI). The...\",\n \"Title: Knowledge based quality analysis of crowdsourced software development platforms\\nYear: 2019\\n\\nAbstract: As an emerging and promising approach, crowdsourcing-based software development has become popular in many domains due to the participation of talented pool of developers in the contests, and to promote the ability of requesters (or customers) to choose the ‘wining’ solution with respect to their desired quality levels. However, due to lack of a central mechanism for team formation, continuity in the developer’s work on consecutive tasks and risk of noise in submissions of a contest, there is a gap between the requesters of a domain and their quality concerns related to the adaptation of a crowdsourcing-based software development platform. In order to address concerns and aid requesters, we describe three measures; Quality of Registrant Developers (QRD), Quality of Contest (QC) and Quality of Support (QS) to compute and predict the quality of a crowdsourcing-based platform through historical information on its completed tasks. We evaluate the capacity of the QRD, QC and QS as assessors to predict the quality. Subsequently, we implement a crawler to mine the information of completed development tasks from the TopCoder platform to inspect the proposed measures. The promising results of our QRD, QC, and QS measures suggest to use the proposed measures to the requesters and researchers of other domains such as pharmaceutical research and development, in order to investigate and predict the quality of crowdsourcing-based software development platforms.\",\n \"Title: GSEPIM: A roadmap for software process assessment and improvement in the domain of global software development\\nYear: 2019\\n\\nAbstract: Software development firms have begun adopting the practice of global software development (GSD). The main reason for the shift toward globalization is the various benefits received by software development firms. However, there are several issues faced by GSD organizations, particularly those associated with software process improvement (SPI). It has been noticed that a formal process improvement approach could assist in successfully executing development activities in GSD. The core objective of this research work is to develop a global software engineering process improvement model (GSEPIM) to assess and improve software process activities in a GSD environment. The proposed model will be developed based on existing models in other domains, an empirical study conducted with GSD practitioners, and an understanding of critical success factors and challenges of SPI. In this study, the first step in the development of GSEPIM is completed by identifying the challenges of SPI in GSD and presenting a solution in the form of a robust framework.\",\n \"Title: A methodology to rank the design patterns on the base of text relevancy\\nYear: 2019\\n\\nAbstract: Several software design patterns have cataloged either with canonical or as variants to solve a recurring design problem. However, novice designers mostly adopt patterns without considering their ground reality and relevance to design problems, which causes to increase the development and maintenance efforts. The existing automated systems to select the design patterns need either high computing effort and time for the formal specification or precise learning through the training of several classifiers with large sample size to select the right design patterns realized on the base of their ground reality. In order to discuss this issue, we propose a method on the base of a supervised learning technique named ‘Learning to Rank’, to rank the design patterns via the text relevancy with the description of the given design problems. Subsequently, we also propose an evaluation model to assess the effectiveness of the proposed method. We evaluate the efficacy of the proposed method in the context of several design pattern collections and relevant design problems. The promising experimental results indicate the applicability of the proposed method as a recommendation system to select the right design pattern(s).\",\n \"Title: A Step towards the Improvement in the Performance of Text Classification.\\nYear: 2019\\n\\nAbstract: The performance of text classification is highly related to the feature selection methods. Usually, two tasks are performed when a feature selection method is applied to construct a feature set; 1) assign score to each feature and 2) select the top-N features. The selection of top-N features in the existing filter-based feature selection methods is biased by their discriminative power and the empirical process which is followed to determine the value of N. In order to improve the text classification performance by presenting a more illustrative feature set, we present an approach via a potent representation learning technique, namely DBN (Deep Belief Network). This algorithm learns via the semantic illustration of documents and uses feature vectors for their formulation. The nodes, iteration, and a number of hidden layers are the main parameters of DBN, which can tune to improve the classifier's performance. The results of experiments indicate the effectiveness of the proposed method to increase the classification performance and aid developers to make effective decisions in certain domains.\",\n \"Title: Prediction of Drug Target Sensitivity in Cancer Cell Lines Using Apache Spark.\\nYear: 2019\\n\\nAbstract: Predicting the drug targets in the base of cancer cell line is one of the hottest issues in cancer treatment. Drug sensitivity describes which drug is perfect for cell line in certain condition or disease. This condition exists due to change in human metabolism. Different techniques are used for cancer treatment such as radiotherapy, hormone therapy, chemotherapy, and surgery. Many statistical methods and machine learning algorithms such as support vector machine, principal component analysis (PCA), logistic regression, simple linear regression, naive Bayes classifier, generalized linear regression, and random forest have been used for drug target prediction. However, these predictors take more time for computation using different tools such as MATLAB and R tool. In this study, different machine learning techniques are applied using Apache Spark to predict drug targets. Apache Spark uses the resilient distributed dataset (RDD) technique for in-memory fast computation and fault tolerance. The obtained results indicate that Spark provides better accuracy in short time when compared with existing tools.\",\n \"Title: Analytics of Heterogeneous Breast Cancer Data Using Neuroevolution.\\nYear: 2019\\n\\nAbstract: Breast cancer prognostic modeling is difficult since it is governed by many diverse factors. Given the low median survival and large scale breast cancer data, which comes from high throughput technology, the accurate and reliable prognosis of breast cancer is becoming increasingly difficult. While accurate and timely prognosis may save many patients from going through painful and expensive treatments, it may also help oncologists in managing the disease more efficiently and effectively. Data analytics augmented by machine-learning algorithms have been proposed in past for breast cancer prognosis; and however, most of these could not perform well owing to the heterogeneous nature of available data and model interpretability related issues. A robust prognostic modeling approach is proposed here whereby a Pareto optimal set of deep neural networks (DNNs) exhibiting equally good performance metrics is obtained. The set of DNNs is initialized and their hyperparameters are optimized using the evolutionary algorithm, NSGAIII. The final DNN model is selected from the Pareto optimal set of many DNNs using a fuzzy inferencing approach. Contrary to using DNNs as the black box, the proposed scheme allows understanding how various performance metrics (such as accuracy, sensitivity, F1, and so on) change with changes in hyperparameters. This enhanced interpretability can be further used to improve or modify the behavior of DNNs. The heterogeneous breast cancer database requires preprocessing for better interpretation of categorical variables in order to improve prognosis from classifiers. Furthermore, we propose to use a neural network-based entity-embedding method for categorical features with high cardinality. This approach can provide a vector representation of categorical features in multidimensional space with enhanced interpretability. It is shown with evidence that DNNs optimized using evolutionary algorithms exhibit improved performance over other classifiers mentioned in this paper.\",\n \"Title: A Methodology to Rank the Patients Prone to Chronic Diseases in Telehealth\\nYear: 2019\\n\\nAbstract: Context: From last decade, telehealth research community have started to use machine learning techniques to automate the certain aspects of healthcare systems for prediction of patients prone to chronic diseases such as checking of insulin level, cancer, and monitoring blood-glucose levels. Though existing automated systems aid the telehealth practitioner, however high computing effort, time, and cost is required in terms of several classifiers, multi class problem, or large sample size to obtained results on the basis of ground reality. Goal: We work on this concern and propose a methodology which is employed via \\\"Learning to Rank\\\" (i.e., a supervised learner) to rank the patients on the basis of their data relevancy. We also propose a model to investigate the efficacy of the proposed method. We assess tie efficacy of the proposed method with seven public datasets associated with certain diseases. Datasets are retrieved from UCI repository Machine Learning Repository. Results: We observed LambdaMART outperform than AdaRank and Coordinate Ascent with a minor difference in terms of NDCG (Normalized Discounted Cumulative Gain) and MAP (Mean Average Precision) to predict patients prone to chronic diseases. Conclusion: The results of study indicates the usage of the proposed method as a recommendation system to rank the patients on the basis of their severity level.\",\n \"Title: Methodology For The Quantification Of The Effect Of Patterns And Anti-Patterns Association On The Software Quality\\nYear: 2019\\n\\nAbstract: The employment of design patterns is considered as a benchmark of software quality in terms of reducing the number of software faults. However, the quantification of the information about the hinder design issues such as the number of roles, type of design pattern, and their association with anti-pattern classes is still required. The authors propose a new methodology to evaluate the impact of certain design issues on the software quality in terms of quantification of fault density. Firstly, they mine the required information about the classes of each system under study. Secondly, they describe taxonomy to group the classes. Subsequently, they used statistical techniques to formulate and benchmark the results. They include the analysis of four open source projects with six design patterns and six anti-patterns in the case study. The main consequences are (i) the pattern participant classes are less dense in faults, (ii) the classes involved in the structural association between design patterns and anti-patterns are denser in faults, (iii) the pattern participant classes with multi-role and anti-pattern smell association is denser in faults as compared to others. The significant difference between fault density distributions of groups of classes is still unclear and required further empirical investigation.\",\n \"Title: A new auxiliary information based cumulative sum median control chart for location monitoring.\\nYear: 2019\\n\\nAbstract: Control charts are commonly used tools in statistical process control for the detection of shifts in process parameters. Shewhart-type charts are efficient for large shift values, whereas cumulative sum (CUSUM) charts are effective in detecting medium and small shifts. Control chart use commonly assumes that data are free of outliers and parameters are known or correctly estimated based on an in-control process. In practice, these assumptions are not often true because some processes occasionally have outliers. Monitoring the location parameter is usually based on mean charts, which are seriously affected by violations of these assumptions. In this paper we propose several CUSUM median control charts based on auxiliary variables, and offer comparisons with their corresponding mean control charts. To monitor the location parameter, we examined the performance of mean and median control charts in the presence and absence of outliers. Both symmetric and non-symmetric processes were studied to examine the properties of the proposed control charts to monitor the location parameter using CUSUM control charts. We used different run length measures to study in-control and out-of-control performances of CUSUM charts. Results revealed that our proposed control charts perform much better than the traditional charts in the presence of outliers. A real application of our study was provided using data on concrete compressive strength as it relates to the quality of cement manufacturing.\",\n \"Title: Efficient Power Management Algorithm Based on Fuzzy Logic Inference for Electric Vehicles Parking Lot.\\nYear: 2019\\n\\nAbstract: Smart grid is expected to support electric vehicles parking lots with the existing power line infrastructure. In order to support all electric-vehicles (EVs) users to complete their charging needs before leaving the parking lot, the power grid requires that the charging demands of EVs should be within the allowable power limit to avoid the grid overloading. This paper proposes a fuzzy logic inference based algorithm (FLIA) to manage the available power efficiently for EVs in the parking lot. The problem is mathematically formulated and solved by the credibility of the fuzzy inference mechanism to control charging and discharging of the EVs. The key idea is to introduce the fuzzy inference mechanism that evaluates several uncertain input parameters from the electric grid and from EVs to obtain an adequately accurate charging or discharging decision for each of the connected EVs. The proposed scheme is applied to a parking lot with different parking capacities and compared with the conventional-based systems. The simulation results demonstrated the feasibility and effectiveness of the proposed algorithm when dealing with the available power management and satisfying the EV user's requirements.\",\n \"Title: A methodology to characterize and compute correlation between traffic congestion and health issues via social media\\nYear: 2018\\n\\nAbstract: Traffic congestion is one of the most significant problems around the world. Literature shows various analyses of real time traffic incidents detection and crowd sensing. However, few researchers quantified the traffic congestion impacts on public health. To the best of our knowledge, there is no study, which determines the correlation between traffic congestion and public health issues via social media. In this paper, we propose a methodology to compute the correlation between traffic congestion and public health issues through social media analysis. To purse this task, we have used topic modeling and sentimental analysis. We mined a collection of 97 million tweets extracted from Twitter. Subsequently, different filters are applied to get the most traffic-congested locations around the world and the top health issues in the corresponding areas. Additionally, we have performed sentimental analysis to get the public perception about the initiatives taken to improve the health issues in those regions. We have found 36 most traffic congested cities around the world, such as Mexico, Bangkok, Jakarta and Chongqing etc. Apart from that, heart diseases, respiratory and psychological problems are identified as the common problems in traffic congested cities. Almost 71% public comments shows the negative sentiments. Which reflects their level of frustration about the steps taken to reduce the traffic by the higher authorities.\",\n \"Title: Empirical Investigation of Code Quality Rule Violations in HPC Applications\\nYear: 2021\\n\\nAbstract: In large, collaborative open-source projects, developers must follow good coding standards to ensure the quality and sustainability of the resulting software. This is especially a challenge in high-performance computing projects, which admit a diverse set of contributions over decades of development. Some successful projects, such as the Portable, Extensible Toolkit for Scientific Computation (PETSc), have created comprehensive developer documentation, including specific code quality rules, which should be followed by contributors. However, none of the widely used and highly active open-source HPC projects have a way to automatically check whether these rules, typically expressed informally in English, are being violated. Hence, compliance checking is labor-intensive and difficult to ensure. To address this issue, we propose an automated method for detecting rule violations in HPC applications based on the PETSc development rules. In our empirical study, we consider 46 PETSc-based applications and assess the violations of two C-usage rules. The experimental results demonstrate the efficacy of the proposed method in identifying PETSc rule violations, which can be broadened to other HPC frameworks and extended by us and others in the community to include more rules.\",\n \"Title: Entropy-Based Greedy Algorithm For Decision Trees Using Hypotheses\\nYear: 2021\\n\\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses of values of all attributes. Such decision trees are similar to those studied in exact learning, where membership and equivalence queries are allowed. We present greedy algorithm based on entropy for the construction of the above decision trees and discuss the results of computer experiments on various data sets and randomly generated Boolean functions.\",\n \"Title: An efficient encoder–decoder model for portrait depth estimation from single images trained on pixel-accurate synthetic data\\nYear: 2021\\n\\nAbstract: Depth estimation from a single image frame is a fundamental challenge in computer vision, with many applications such as augmented reality, action recognition, image understanding, and autonomous driving. Large and diverse training sets are required for accurate depth estimation from a single image frame. Due to challenges in obtaining dense ground-truth depth, a new 3D pipeline of 100 synthetic virtual human models is presented to generate multiple 2D facial images and corresponding ground truth depth data, allowing complete control over image variations. To validate the synthetic facial depth data, we propose an evaluation of state-of-the-art depth estimation algorithms based on single image frames on the generated synthetic dataset. Furthermore, an improved encoder–decoder based neural network is presented. This network is computationally efficient and shows better performance than current state-of-the-art when tested and evaluated across 4 public datasets. Our training methodology relies on the use of synthetic data samples which provides a more reliable ground truth for depth estimation. Additionally, using a combination of appropriate loss functions leads to improved performance than the current state-of-the-art network performances. Our approach clearly outperforms competing methods across different test datasets, setting a new state-of-the-art for facial depth estimation from synthetic data.\",\n \"Title: Identification and Authentication in Healthcare Internet-of-Things Using Integrated Fog Computing Based Blockchain Model\\nYear: 2021\\n\\nAbstract: The healthcare Internet-of-Things (IoT) offers many benefits including data transmission in real-time mode, the ability to monitor the physiological state of the patient in a different interval of time. Devices such as blood-pressure monitors, glucose meters, heart monitoring implants, Electroencephalography (EEG), Electrocardiogram (ECG), and Electromyography (EMG) wearable devices allow health providers to collect the patient health information locally and make a real-time decision based on the Patient Health Data (PHD). Hospitals have been adopting the IoT for many years and now they have healthcare IoT devices in patients’ rooms and their bodies. However, the medical agencies, hospitals, and companies do not consider the security risk of healthcare IoT devices connected to a Local Area Network (LAN) or Wide Area Network (WAN). The IoT devices can be easily hacked and may lead to several potentially life-threatening risks due to poor authentication and encryption practices. Existing machine learning algorithms and blockchain approach working in the cloud computing environment are unable to meet the Quality of Service (QoS) like reliability, authentication, identification, and security requirements of healthcare IoT devices. Most of the traditional machine learning algorithms and techniques for healthcare IoT lacks the real-world implementation for secure data transmission. Therefore, blockchain is introduced for secure and reliable transaction in healthcare IoT. Whereas Fog Computing (FC) is introduced to extend the services of the cloud at the edge of networks. Integration of FC with blockchain can overcome the issue of healthcare IoT device identification, authentication, and verification for scalable frequent data transmission in a decentralized environment. Hence, a novel solution for the abovementioned problem is proposed using FC and blockchain. It includes an FC-based three-tier architecture, an analytical model, a mathematical framework, and an Advanced Signature-Based Encryption (ASE) algorithm for healthcare IoT device identification, verification, and Patient Health Data (PHD) authentication. The aim is to extend secure data transmission for healthcare IoT and end-users availing the real-time services. The proposed model and algorithm will be able to provide services for transaction and transmission near the edge in a secure manner. By analyzing the generated results from the proposed novel ASE algorithm for throughput, packet error, reliability, and malicious node detection accuracy; it is observed that the ASE algorithm in the FC environment easily outperforms the cloud and the other existing state of the art techniques such as FogBus, Femto cloud, Blockchain Fog-based Architecture Network (BFAN), and BeeKeeper. The malicious node detection accuracy of the ASE algorithm in the FC environment is 91% and in the cloud is 83%. Whereas the reliability percentage of the ASE algorithm in FC is 95% and in the cloud is 87%. The proposed approach is tested on simulators iFogSim (Net-Beans) and SimBlock.\",\n \"Title: Minimizing Depth of Decision Trees with Hypotheses\\nYear: 2021\\n\\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses about values of all attributes. Such decision trees are similar to ones studied in exact learning, where membership and equivalence queries are allowed. We present dynamic programming algorithms for minimization of the depth of above decision trees and discuss results of computer experiments on various data sets and randomly generated Boolean functions.\",\n \"Title: A Blockchain-Enabled Fog Computing Model for Peer-To-Peer Energy Trading in Smart Grid\\nYear: 2021\\n\\nAbstract: The advancement in renewable energy sources (RESs) technology have changed the role of traditional consumers to prosumers. In contrast to the traditional power grid, the Smart Grid (SG) network provides a platform for peer-to-peer (P2P) energy trading between prosumers to buy or sell energy according to their requirements. The potential benefits of P2P energy trading can be realized through an efficient service provider of the communication network infrastructure. However, the current communication network is a trustless environment and thereby is unable to fully support the P2P energy trading requirements. Existing techniques in P2P energy trading with blockchain suffers from large network delay due to large network size; this further affects the network performance for P2P trading. In this paper, we present a novel Blockchain-Based Smart Energy Trading (BSET) algorithm along with a Blockchain-Enabled Fog Computing Model (BFCM) for P2P energy trading in Smart Grid. The proposed BSET algorithm provides a fully trusted minimum latency communication network that enables the prosumers to trade energy within their local premises. The algorithm was implemented using iFogSim, Truffle, ATOM, Anaconda, and Geth and evaluated against state-of-the-art communication network models for P2P energy trading. The simulation results revealed the effectiveness in terms of secure trading and network latency.\",\n \"Title: Minimizing Number of Nodes in Decision Trees with Hypotheses\\nYear: 2021\\n\\nAbstract: In this paper, we consider decision trees that use both conventional queries based on one attribute each and queries based on hypotheses about values of all attributes. This approach is similar to one studied in exact learning, where membership and equivalence queries are considered. We propose dynamic programming algorithms for the minimization of the number of nodes in such decision trees and discuss results of computer experiments. (C) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://crativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of KES International.\",\n \"Title: Decision Rules Derived from Optimal Decision Trees with Hypotheses\\nYear: 2021\\n\\nAbstract: Conventional decision trees use queries each of which is based on one attribute. In this study, we also examine decision trees that handle additional queries based on hypotheses. This kind of query is similar to the equivalence queries considered in exact learning. Earlier, we designed dynamic programming algorithms for the computation of the minimum depth and the minimum number of internal nodes in decision trees that have hypotheses. Modification of these algorithms considered in the present paper permits us to build decision trees with hypotheses that are optimal relative to the depth or relative to the number of the internal nodes. We compare the length and coverage of decision rules extracted from optimal decision trees with hypotheses and decision rules extracted from optimal conventional decision trees to choose the ones that are preferable as a tool for the representation of information. To this end, we conduct computer experiments on various decision tables from the UCI Machine Learning Repository. In addition, we also consider decision tables for randomly generated Boolean functions. The collected results show that the decision rules derived from decision trees with hypotheses in many cases are better than the rules extracted from conventional decision trees.\",\n \"Title: Self-adaptation in smartphone applications: Current state-of-the-art techniques, challenges, and future directions\\nYear: 2021\\n\\nAbstract: Context: In the last few years, smartphones have become an essential part of our lives. Several mobile applications have been uploaded to their respective app stores on daily basis to facilitate the end-users. To ensure the availability of the application and its services, the application needs to be able to detect and deal with various types of changes. Mobile application based self-adaptation is regarded as a solution to handle the above-mentioned chnages. Objective: The objectives of this study are: (i) identification of current state-of-the-art tech-niques, frameworks, models, and algorithms for self-adaptation in mobile applications context, (ii) exploring the core challenges faced in the development of self-adaptive mobile applications, and (iii) conducting a SWOT (Strength Weakness Opportunity Threat) analysis to figure out the research gaps in the targeted research field. Method: To accomplish the mentioned objective, we conducted a systematic literature review to enlighten the need for adaptation in this domain, the targeted areas, their beneficial aspects, state-of-the-art proposed solutions, and their challenges. We performed the keyword-based search on 11 well-known databases to determine the potential studies published between years 2015 to 2020. In total, 31 studies (from 933 potential studies) are selected grounded on the defined inclusion and exclusion criteria. Results: The main findings of this work are: (i) MAPE-K (Monitor Analyze Plan Execute-Knowledge) model is frequently used in several studies due to its resilience, (ii) current work focuses on the android operating system due to its popularity and flexibility; however, it lacks in considering other mobile's operating systems, and (iii) reported work also lacks in mentioning any benchmark (self-adaptive framework). Conclusion: The current study is helpful for the researchers intended to work in the smart-phones domain. From developers viewpoint, this study reports the faced challenges during the development of smartphones applications. Moreover, the performed study is beneficial in filling the identified research gaps by providing a foundation useful to plan future research regarding self-adaptation in smartphone applications context.\",\n \"Title: Torque Ripples Reduction and Performance Analysis of Electrically Excited Flux Switching Motor\\nYear: 2022\\n\\nAbstract: Torque ripples cause acoustic noise, fluctuation in speed, vibration, and reduce lifetime of the motor. The double salient structure of Flux Switching Motor (FSM) has a high air-gap permeance variation that produces high torque ripples. This paper presents an analytical model to reduce air-gap permeance variation and torque ripples of the proposed octane modular stator 8slots-6poles single-phase Electrically Excited (EE) FSM. Furthermore, the rotor pole shaping technique is used to minimize the air-gap permeance variation and therefore, torque ripples of the proposed design are reduced. The electromagnetic performance of EEFSM is analyzed via the Finite Element Analysis (FEA) method. For the proposed design magnetic flux harmonics are reduced by 71% and back-EMF harmonics are suppressed by 48.5%. Torque ripples of the proposed EEFSM are reduced by 20%, cogging torque is diminished by 42.7% and average torque is enhanced by 5.8%. Finally, the prototype is fabricated and tested experimentally. Calculated values and experimental results are in good agreement and the difference is 3.5%-5%.\",\n \"Title: A continuum viscoelastic model of Timoshenko NSGT nanobeams\\nYear: 2022\\n\\nAbstract: Developed and solved in this article, for the first time, is a coupled continuum viscoelastic model for Timoshenko nonlocal strain gradient theory (NSGT)-based nanobeams; this is performed using a finite difference analysis (FDA). The viscosity of infinitesimal elements of the Timoshenko NSGT nanobeams is incorporated via the Kelvin-Voigt scheme (as a two-parameter rheological scheme) for both the transverse/longitudinal/rotational motions. The NSGT for the normal/shear stress fields is used for ultrasmall size influences on the continuum model. Rotary inertia is automatically present due to the Timoshenko-type rotation. The viscosity in the Timoshenko NSGT nanobeam is responsible for energy dissipation formulated via negative work. Hamilton's balance scheme is utilised and resulted in the coupled continuum viscoelastic dynamic model for Timoshenko NSGT nanobeams, which is solved via a FDA for nonlinear mechanics. A nonlinear bending test is conducted via development of a finite element method model in the absence of the NSGT.\",\n \"Title: Investigation of Inner/Outer Rotor Permanent Magnet Flux Switching Generator for Wind Turbine Applications\\nYear: 2021\\n\\nAbstract: In this paper two permanent magnet flux switching generator (PMFSG) is designed for 2 kW output power and 220 V phase voltage at 1500 rpm and comparatively analyzed for wind turbine applications. Both PMFSG share same C-core stator connected back-to-back through flux bridge (beta) with different rotor position i.e., inner rotor PMFSG (IR-PMFSG) and outer rotor PMFSG (OR-PMFSG). A detailed comparative analysis with various beta for both IR-PMFSG and OR-PMFSG are performed under static characteristics, rated condition, overload capability and over-speed capability for generating output voltage, current, power and efficiency. Comparison of the static characteristics reveal that IR-PMFSG offers 47.93% higher rated power, 2.83% higher efficiency, 22.78% more magnetic flux, 56.91% reduced cogging torque and 83.18% lower torque ripples at the cost of 62.69% higher voltage regulation factor. Furthermore, under rated operating condition and overload capability with same specifications it is found that IR-PMFSG exhibits 1.47 times power than that of OR-PMFSG counterpart. Finally, over-speed capability is investigated in term of the output power which shows that IR-PMFSG significantly generate almost 2.25 time of the specification power whereas OR-PMFSG exhibits nearly 1.25 times power. This analysis shows that IR-PMFSG can be operated at wide-speed rage for higher power specification requirements maintaining efficiency greater than 90%.\",\n \"Title: A Review of Benchmark Datasets and Training Loss Functions in Neural Depth Estimation\\nYear: 2021\\n\\nAbstract: In many applications, such as robotic perception, scene understanding, augmented reality, 3D reconstruction, and medical image analysis, depth from images is a fundamentally ill-posed problem. The success of depth estimation models relies on assembling a suitably large and diverse training dataset and on the selection of appropriate loss functions. It is critical for researchers in this field to be made aware of the wide range of publicly available depth datasets along with the properties of various loss functions that have been applied to depth estimation. Selection of the right training data combined with appropriate loss functions will accelerate new research and enable better comparison with state-of-the-art. Accordingly, this work offers a comprehensive review of available depth datasets as well as the loss functions that are applied in this problem domain. These depth datasets are categorised into five primary categories based on their application, namely (i) people detection and action recognition, (ii) faces and facial pose, (iii) perception-based navigation (i.e., street signs, roads), (iv) object and scene recognition, and (v) medical applications. The important characteristics and properties of each depth dataset are described and compared. A mixing strategy for depth datasets is presented in order to generalise model results across different environments and use cases. Furthermore, depth estimation loss functions that can help with training deep learning depth estimation models across different datasets are discussed. State-of-the-art deep learning-based depth estimation methods evaluations are presented for three of the most popular datasets. Finally, a discussion about challenges and future research along with recommendations for building comprehensive depth datasets will be presented as to help researchers in the selection of appropriate datasets and loss functions for evaluating their results and algorithms.\",\n \"Title: A Comparative Study of Dual Stator With Novel Dual Rotor Permanent Magnet Flux Switching Generator for Counter Rotating Wind Turbine Applications\\nYear: 2022\\n\\nAbstract: Compared with the single rotor wind turbine, a counter-rotating (CR) wind turbine with two rotor sets leads to twice power density. In this regard, dual stator CR (DSCR) permanent magnet flux switching generator (DSCR-PMFSG) is employed. However, in DSCR-PMFSG both rotor and armature parts are rotating and require slip rings for power transmission. These slip rings associate demerits of constant maintenance, poor speed regulation, increased cost, and additional slip ring losses, whereas DSCR-PMFSG offer lower flux and lesser power density. To overcome the demerits of DSCR-PMFSG as mentioned earlier, this paper proposed a novel dual rotor counter-rotating permanent magnet flux switching generator (DRCR-PMFSG) for wind turbine applications that eliminate the requirements of slip rings and retain brushless operation. The proposed DRCR-PMFSG share one stator connected back-to-back through a flux bridge that provides an alternate flux path between two mechanical ports associated with the inner rotor and outer rotor, contributing to the cumulative output. A detailed comparative analysis of DSCR-PMFSG and DRCR-PMFSG is performed under static characteristics, overload, and wide speed range to generate output power, voltage, current, power density, and efficiency. Quantitative comparative analysis under static analysis evident that proposed DRCR-PMFSG exhibits 33.29% higher flux, suppressed cogging torque and torque ripples up to 53.48% and 67.45%, respectively. Furthermore, a comprehensive quantitative analysis is performed under coupled overload and over-speed capability. Analysis exposes that in comparison with DSCRP-PMFSG, the proposed DRCR-PMFSG improves voltage regulation factor by 55.88%, output current enhanced by 67.9%, raise output voltage to 2.01 times, and power density to 1.72 times while maintaining the efficiency of 90.195% and achieving stable voltage profile with load variation. Finally, a detailed comparative analysis with conventional designs is performed and comprehensive mathematical modelling based on sub-domain model is developed accounting stator slot and rotor pole combinations, magnetic saturation, and winding configuration to validates finite element analysis (FEA) of JMAG Designer v.20.1.\",\n \"Title: A Novel Dual Rotor Permanent Magnet Flux Switching Generator for Counter Rotating Wind Turbine Applications\\nYear: 2022\\n\\nAbstract: In this paper counter rotating (CR) dual rotor permanent magnet flux switching generator (CR-DRPMFSG) is designed and relatively studied with co- rotating DRPMFSG (CoR-DRPMFSG) for wind turbine applications. The developed CR- DRPMFSG and CoR-DRPMFSG share same stator linked with flux bridge which provide flux route. A comprehensive relative assessment of both CR- DRPMFSG and CoR-DRPMFSG are presented with static attributes, over-load, and over-speed capability for generating output voltage, output current, output power, power density, losses, and efficiency. Comparative study with static characteristics illustrates that developed CR- DRPMFSG shows 34.34% elevated phase flux which improve output power, cumulative output torque is improved by 23.86%, and suppressed cogging torque by 66.87% at CoR-DRPMFSG that results lower pulsation in instantaneous torque. Furthermore, a detailed performance analysis is investigated with different number of armature winding turns per phase and combined over-load and over-speed capability. Study discloses that in contrast with CoR-DRPMFSG, counterpart CR- DRPMFSG offer 27.17% higher output power that results 1.25 times power density with a good voltage regulation factor of 18.67%. In additional, despite of 2.27% improvement of efficiency in case of phase winding turns analysis and 4.81% increase in over-load and over-speed capability, contour efficiency map unveils that CR- DRPMFSG offer wide range of higher efficiency operating region during over-load and over-speed condition accompany with stable voltage profile with load variation.\",\n \"Title: Development of a Low-Cost Modular Structure Fault Tolerant Field Excited Flux Switching Linear Machine for Urban Rail Transit\\nYear: 2021\\n\\nAbstract: This paper proposes double sided complementary modular field excited flux switching linear machine (FEFSLM). FEFSLM offers the low cost, variable flux capability for a wide speed range, a compact and robust stator which is suitable for the long stroke application. Compared to other linear machines, complementary modular design has more sinusoidal and symmetrical flux linkage and lower detent force. Initially, the topology and machine working principle is thoroughly discussed. To maximize the thrust force of the machine and optimize the geometric parameters, built-in genetic algorithm (GA) of JMAG ver. 20 is utilized. Furthermore, the modular design incorporates the concept of fault-tolerant capabilities to provide the required decoupling between phases. 2D finite element analysis (FEA) is used to analyze the machine performance. Comparatively the optimized design exhibits higher thrust force, lower thrust force ripples and higher efficiency than the initial design.\",\n \"Title: Design synthesis and optimization of a 4-SPS intrinsically compliant parallel wrist rehabilitation robotic orthosis\\nYear: 2021\\n\\nAbstract: Neuroplasticity allows the human nervous system to adapt and relearn motor control following stroke. Rehabilitation therapy, which enhances neuroplasticity, can be made more effective if assisted by robotic tools. In this paper, a novel 4-SPS parallel robot has been developed to provide recovery of wrist movements post-stroke. The novel mechanism presented here was inspired by the forearm anatomy and can provide the rotational degrees of freedom required for all wrist movements. The robot design has been discussed in detail along with the necessary constructional, kinematic, and static analyses. The spatial workspace of the robot is estimated considering various dimensional and application-specific constraints besides checking for singular configurations. The wrist robot has been further evaluated using important performance indices such as condition number, actuator forces, and stiffness. The pneumatic artificial muscles exhibit varying stiffness, and therefore, workspace points are reached with different overall stiffness of the robot. It is essential to assess robot workspace points that can be reached with positive forces in actuators while maintaining a positive definite overall stiffness matrix. After the above analysis, design optimization has been carried out using an evolutionary algorithm whereby three critical criteria are optimized simultaneously for optimal wrist robot design.\",\n \"Title: Threshold-Based Analysis of the Code Quality of High-Performance Computing Software Packages\\nYear: 2020\\n\\nAbstract: Many popular metrics used for the quantification of the quality or complexity of a codebase (e.g. cyclomatic complexity) were developed in the 1970s or 1980s when source code sizes were significantly smaller than they are today, and before a number of modern programming language features were introduced in different languages. Thus, the many thresholds that were suggested by researchers for decidi...\",\n \"Title: Consequences of Flux Gap on Intriguing Features of Modular Stator Inset Permanent Magnet Consequent Pole Synchronous Machine\\nYear: 2022\\n\\nAbstract: In this paper a novel Inset Permanent Magnet Consequent Pole Synchronous Machine (IPMCPSM) with H-type modular stator core for higher average torque (T-alpha), torque density (T-d), power density (P-d) and efficiency (eta) with features of reduced torque ripple ratio (T-r) and harmonics content in back-EMF (EMFTHD) are proposed. Detailed static analysis of the proposed IPMCPSM under variable flux gaps at all and alternate stator teeth is investigated. Performance analyses disclose that with variable flux gaps in proposed IPMCPSM, beside improved flux weakening capability due to flux focusing effects, electromagnetic performance is greatly improved. Additionally, due to physical isolation of the adjacent phase modules with modular topology, mutual flux influence is de-coupled that improve phase self-inductance to mitigate the short-circuited current under fault condition whereas mutual flux decoupling mitigates mutual inductance that ultimately improves overall machine fault-tolerant capability. Furthermore, effectiveness of the proposed IPMCPSM with H-type modular stator is elaborated with comparative study of conventional E-core and C-core topologies. Detailed comparative analysis reveals that proposed IPMCPSM suppresses EMFTHD, improve eta by 18.9%, diminish T-r up to 55% and boost T-alpha and P-d maximum up to 2.66, 2.59 times, respectively with enhanced flux focusing effects and fault tolerant capability.\",\n \"Title: Porosity, mass and geometric imperfection sensitivity in coupled vibration characteristics of CNT-strengthened beams with different boundary conditions\\nYear: 2022\\n\\nAbstract: Structures face different types of imperfections and defects during the fabrication process, installation and working environment. In this paper, the imperfection effects in the coupled vibration behaviour of axially functionally graded carbon nanotube (CNT)-strengthened beam structures with different boundary conditions are analysed considering porosity as well as geometric and mass imperfections in the structure. Porosity is modelled using different types of formulations for simple-cell, open-cell and closed-cell porous structures. The porosity is assumed to be either uniform or by varying through the thickness of the hollow beam using different functions. Mass imperfection effect is added to the system by considering a concentrated mass in the system affecting the mass homogeneity of the structure. Geometry imperfection is also considered by having an initial deformation in the structure which could be caused by an improper fabrication process. Coupled axial and transverse equations of motion are obtained using Hamilton’s principle and the von Kármán geometrical nonlinearity. Governing equations are solved for different types of boundary conditions using a semi-analytical modal decomposition technique. It is shown that strengthening the base matrix with CNT fibres can improve the vibration behaviour of imperfect structures and the influence of CNT volume fraction and distribution through the length of the beam is discussed. The results provided in this paper may be used as a benchmark to validate future experimental results to prevent imperfection, delamination and stress singularities in the structures.\",\n \"Title: Analytical Modeling of Novel High Thrust Force Density Segmented PM Consequent Pole Linear Flux Switching Machine\\nYear: 2022\\n\\nAbstract: Permanent Magnet Linear Flux Switching Machines (PMLFSMs) are potential candidates when higher thrust force (T-F) and low cost are the primal requirements. However, conventional PMLFSMs shows flux leakages and utilizes high Permanent Magnet (PM) volume (V-PM) that increase overall expense. Therefore, this paper proposed novel Segmented PM Consequent Pole Linear Flux Switching Machine (SPMCPLFSM) with flux bridges. In comparison with PMLFSM, the proposed SPMCPLFSM diminish detent force by 20.41%, suppress thrust force ripples by 27.68%, reduces ripple ratio by 1.77 times, improve T-F to 2 times and boost T-F density to 2.64 times utilizing 75% PM volume and reducing PM cost by 24.16%. Moreover, to overcome computational complexity and computation time, analytical model uniting Lumped Parametric Magnetic Equivalent Circuits, vector potential and Maxwell Stress Tensor method are utilized for open circuit flux linkages, magnetic flux density, detent force and thrust force. Finally, analytical model is validated with finite element analysis (FEA) that show good agreement with FEA. Thus, authors are assured to suggest analytical techniques for early design purpose and proposed SPMCPLFSM for roller coaster application.\",\n \"Title: A two-layer decentralized charging approach for residential electric vehicles based on fuzzy data fusion\\nYear: 2022\\n\\nAbstract: This work presents a two-layer decentralized charging approach (TLDCA) based on fuzzy data fusion concerning the economic and power layers for optimizing the charging cost of residential electric vehicles (EVs). We defined the problem with the fuzzy objective function of minimizing the charging costs and presented a detailed fuzzy integer linear programming formulation for obtaining the optimal solution set. The optimal solution set relies on the decision control variable which is obtained through the fuzzy fusion mechanism that incorporates multiple independent and uncertain day-ahead price patterns and state-of-charge inputs from the utility grid and EV domains. The developed TLDCA reduces the charging cost for EVs while guaranteeing their required energy by determining the optimal charging schedule. We conduct two case studies to investigate the TLDCA behavior, where the first case explores the optimization of charging costs and the changing needs of individual EVs. The second case examines the charging cost, impact on load profile, and peak-to-average ratio against the summer and winter load profiles for the aggregated EVs. The simulation results verify that the developed TLDCA optimizes the charging cost and peak-to-average ratio compared to the uncoordinated charging, standard-rate charging, and time-of-use charging schemes.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":92,"string":"92"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13370,"string":"13,370"}}},{"rowIdx":13371,"cells":{"question_id":{"kind":"string","value":"Munmun De Choudhury"},"question":{"kind":"string","value":"Generate an abstract for the title \"Can blog communication dynamics be correlated with stock market activity?\" using the following items: 1. Communication dynamics\n2. Blogosphere\n3. Stock market movement\n4. Support Vector Machine\n5. Correlation measures"},"answer":{"kind":"string","value":"In this paper, we develop a simple model to study and analyze communication dynamics in the blogosphere and use these dynamics to determine interesting correlations with stock market movement. This work can drive targeted advertising on the web as well as facilitate understanding community evolution in the blogosphere. We describe the communication dynamics by several simple contextual properties of communication, e.g. the number of posts, the number of comments, the length and response time of comments, strength of comments and the different information roles that can be acquired by people (early responders / late trailers, loyals / outliers). We study a \"technology-savvy\" community called Engadget (http://www.engadget.com). There are two key contributions in this paper: (a) we identify information roles and the contextual properties for four technology companies, and (b) we model them as a regression problem in a Support Vector Machine framework and train the model with stock movements of the companies. It is interestingly observed that the communication activity on the blogosphere has considerable correlations with stock market movement. These correlation measures are further cross-validated against two baseline methods. Our results are promising yielding about 78% accuracy in predicting the magnitude of movement and 87% for the direction of movement."},"correct_answer":{"kind":"string","value":"In this paper, we develop a simple model to study and analyze communication dynamics in the blogosphere and use these dynamics to determine interesting correlations with stock market movement. This work can drive targeted advertising on the web as well as facilitate understanding community evolution in the blogosphere. We describe the communication dynamics by several simple contextual properties of communication, e.g. the number of posts, the number of comments, the length and response time of comments, strength of comments and the different information roles that can be acquired by people (early responders / late trailers, loyals / outliers). We study a \"technology-savvy\" community called Engadget (http://www.engadget.com). There are two key contributions in this paper: (a) we identify information roles and the contextual properties for four technology companies, and (b) we model them as a regression problem in a Support Vector Machine framework and train the model with stock movements of the companies. It is interestingly observed that the communication activity on the blogosphere has considerable correlations with stock market movement. These correlation measures are further cross-validated against two baseline methods. Our results are promising yielding about 78% accuracy in predicting the magnitude of movement and 87% for the direction of movement."},"documents":{"kind":"list like","value":["Title: Discovering multirelational structure in social media streams\nYear: 2012\n\nAbstract: In this article, we present a novel algorithm to discover multirelational structures from social media streams. A media item such as a photograph exists as part of a meaningful interrelationship among several attributes, including time, visual content, users, and actions. Discovery of such relational structures enables us to understand the semantics of human activity and has applications in content organization, recommendation algorithms, and exploratory social network analysis. We are proposing a novel nonnegative matrix factorization framework to characterize relational structures of group photo streams. The factorization incorporates image content features and contextual information. The idea is to consider a cluster as having similar relational patterns; each cluster consists of photos relating to similar content or context. Relations represent different aspects of the photo stream data, including visual content, associated tags, photo owners, and post times. The extracted structures minimize the mutual information of the predicted joint distribution. We also introduce a relational modularity function to determine the structure cost penalty, and hence determine the number of clusters. Extensive experiments on a large Flickr dataset suggest that our approach is able to extract meaningful relational patterns from group photo streams. We evaluate the utility of the discovered structures through a tag prediction task and through a user study. Our results show that our method based on relational structures, outperforms baseline methods, including feature and tag frequency based techniques, by 35%--420%. We have conducted a qualitative user study to evaluate the benefits of our framework in exploring group photo streams. The study indicates that users found the extracted clustering results clearly represent major themes in a group; the clustering results not only reflect how users describe the group data but often lead the users to discover the evolution of the group activity.","Title: \"Moon Phrases\": a social media faciliated tool for emotional reflection and wellness\nYear: 2013\n\nAbstract: We propose an early prototype: a web-based tool \"Moon Phrases\" that leverages an individual's social activity online for promoting emotional reflection and wellness. Specifically, Moon Phrases tracks the emotion and linguistic expression of individuals as manifested on the social media Twitter, and presents a novel visualization---an analogy to the phases of the moon, to reveal their longitudinal trends. Social media platforms, including Twitter and Facebook provide a window onto the thoughts and feelings of individuals around small and big happenings in their lives. Motivated from research in psychology and HCI, we hypothesize that identifying the changes in language, emotion, and social activity on social media would enable individuals to reflect on their own behavior over time and in a fine-grained manner, which are otherwise known to be difficult to keep track of. We believe Moon Phrases thus bears the potential to act as a self-narrative or \"behavioral fingerprint\", and thereby serve as an unobtrusive mechanism to facilitate emotional wellness in individuals.","Title: Inferring relevant social networks from interpersonal communication\nYear: 2010\n\nAbstract: Researchers increasingly use electronic communication data to construct and study large social networks, effectively inferring unobserved ties (e.g. i is connected to j) from observed communication events (e.g. i emails j). Often overlooked, however, is the impact of tie definition on the corresponding network, and in turn the relevance of the inferred network to the research question of interest. Here we study the problem of network inference and relevance for two email data sets of different size and origin. In each case, we generate a family of networks parameterized by a threshold condition on the frequency of emails exchanged between pairs of individuals. After demonstrating that different choices of the threshold correspond to dramatically different network structures, we then formulate the relevance of these networks in terms of a series of prediction tasks that depend on various network features. In general, we find: a) that prediction accuracy is maximized over a non-trivial range of thresholds corresponding to 5-10 reciprocated emails per year; b) that for any prediction task, choosing the optimal value of the threshold yields a sizable (~30%) boost in accuracy over naive choices; and c) that the optimal threshold value appears to be (somewhat surprisingly) consistent across data sets and prediction tasks. We emphasize the practical utility in defining ties via their relevance to the prediction task(s) at hand and discuss implications of our empirical results.","Title: CONNECTING CONTENT TO COMMUNITY IN SOCIAL MEDIA VIA IMAGE CONTENT, USER TAGS AND USER COMMUNICATION\nYear: 2009\n\nAbstract: In this paper we develop a recommendation framework to connect image content with communities in online social media. The problem is important because users are looking for useful feedback on their uploaded content, but finding the right community for feedback is challenging for the end user. Social media are characterized by both content and community. Hence, in our approach, we characterize images through three types of features: visual features, user generated text tags, and social interaction (user communication history in the form of comments). A recommendation framework based on learning a latent space representation of the groups is developed to recommend the most likely groups for a given image. The model was tested on a large corpus of Flickr images comprising 15,689 images. Our method outperforms the baseline method, with a mean precision 0.62 and mean recall 0.69. Importantly, we show that fusing image content, text tags with social interaction features outperforms the case of only using image content or tags.","Title: \"Narco\" emotions: affect and desensitization in social media during the mexican drug war\nYear: 2014\n\nAbstract: Social media platforms have emerged as prominent information sharing ecosystems in the context of a variety of recent crises, ranging from mass emergencies, to wars and political conflicts. We study affective responses in social media and how they might indicate desensitization to violence experienced in communities embroiled in an armed conflict. Specifically, we examine three established affect measures: negative affect, activation, and dominance as observed on Twitter in relation to a number of statistics on protracted violence in four major cities afflicted by the Mexican Drug War. During a two year period (Aug 2010 - Dec 2012), while violence was on the rise in these regions, our findings show a decline in negative emotional expression as well as a rise in emotional arousal and dominance in Twitter posts: aspects known to be psychological markers of desensitization. We discuss the implications of our work for behavioral health, facilitating rehabilitation efforts in communities enmeshed in an acute and persistent urban warfare, and the impact on civic engagement.","Title: \"Understanding our online communication processes\" by Munmun De Choudhury with Danielle H. Lee as coordinator\nYear: 2012\n\nAbstract: This article presents an overview of the dissertation work entitled \"Analyzing the Dynamics of Communication in Online Social Networks\", by Munmun De Choudhury. It was completed in 2011 at the Arizona State University, Tempe, under the supervision of Prof. Hari Sundaram. The dissertation deals with the analysis of interpersonal communication dynamics in online social networks and social media. Communication dynamics have been of interest to researchers from multi-faceted domains over the past several decades. However, today we are faced with several modern capabilities encompassing a host of social media websites. This research is geared towards developing methods, tools and frameworks towards understanding and addressing the associated challenges of making sense of the modern online communication processes. We believe that this research can make significant contribution into a better understanding of how we communicate online and how it is redefining our collective sociological behavior.","Title: Identifying relevant social media content: leveraging information diversity and user cognition\nYear: 2011\n\nAbstract: As users turn to large scale social media systems like Twitter for topic-based content exploration, they quickly face the issue that there may be hundreds of thousands of items matching any given topic they might query. Given the scale of the potential result sets, how does one identify the 'best' or 'right' set of items? We explore a solution that aligns characteristics of the information space, including specific content attributes and the information diversity of the results set, with measurements of human information processing, including engagement and recognition memory. Using Twitter as a test bed, we propose a greedy iterative clustering technique for selecting a set of items on a given topic that matches a specified level of diversity. In a user study, we show that our proposed method yields sets of items that were, on balance, more engaging, better remembered, and rated as more interesting and informative compared to baseline techniques. Additionally, diversity indeed seemed to be important to participants in the study in the consumption of content. However as a rather surprising result, we also observe that content was perceived to be more relevant when it was highly homogeneous or highly heterogeneous. In this light, implications for the selection and evaluation of topic-centric item sets in social media contexts are discussed.","Title: Discovery of information disseminators and receptors on online social media\nYear: 2010\n\nAbstract: Today, there is significant sharing of information artifacts among users on various social media sites, including Digg, Twitter and Flickr. An interesting consequence of such rich and extensive social interaction is the evolving nature of \"roles\" that are acquired by users over time, in the context of variegated communication activities, such as commenting, replying, uploading a media artifact and so on. In this paper, we investigate the discovery of two roles that define information dissipation: disseminators and receptors. We propose a computational framework based on factorization of stacked representation of activities and test the outcomes on a dataset from Digg. Experiments show that our approach can, interestingly, reveal correlations with user activities occurring at a future point in time.","Title: Characterizing and predicting postpartum depression from shared facebook data\nYear: 2014\n\nAbstract: The birth of a child is a major milestone in the life of parents. We leverage Facebook data shared voluntarily by 165 new mothers as streams of evidence for characterizing their postnatal experiences. We consider multiple measures including activity, social capital, emotion, and linguistic style in participants' Facebook data in pre- and postnatal periods. Our study includes detecting and predicting onset of post-partum depression (PPD). The work complements recent work on detecting and predicting significant postpartum changes in behavior, language, and affect from Twitter data. In contrast to prior studies, we gain access to ground truth on postpartum experiences via self-reports and a common psychometric instrument used to evaluate PPD. We develop a series of statistical models to predict, from data available before childbirth, a mother's likelihood of PPD. We corroborate our quantitative findings through interviews with mothers experiencing PPD. We find that increased social isolation and lowered availability of social capital on Facebook, are the best predictors of PPD in mothers.","Title: Finding and assessing social media information sources in the context of journalism\nYear: 2012\n\nAbstract: Social media is already a fixture for reporting for many journalists, especially around breaking news events where non-professionals may already be on the scene to share an eyewitness report, photo, or video of the event. At the same time, the huge amount of content posted in conjunction with such events serves as a challenge to finding interesting and trustworthy sources in the din of the stream. In this paper we develop and investigate new methods for filtering and assessing the verity of sources found through social media by journalists. We take a human centered design approach to developing a system, SRSR (\"Seriously Rapid Source Review\"), informed by journalistic practices and knowledge of information production in events. We then used the system, together with a realistic reporting scenario, to evaluate the filtering and visual cue features that we developed. Our evaluation offers insights into social media information sourcing practices and challenges, and highlights the role technology can play in the solution.","Title: Dynamic prediction of communication flow using social context\nYear: 2008\n\nAbstract: In this paper, we develop a temporally evolving representation framework for context that can efficiently predict communication flow in social networks between a given pair of individuals. The problem is important because it facilitates determining social and market trends as well as efficient information paths among people. We describe communication flow by two parameters: the intent to communicate and communication delay. To estimate these parameters, we design features to characterize communication and social context. Communication context refers to the attributes of current communication. Social context refers to the patterns of participation in communication (information roles) and the degree of overlap of friends between two people (strength of ties). A subset of optimal features of the communication and social context is chosen at a given time instant using five different feature selection strategies. The features are thereafter used in a Support Vector Regression framework to predict the intent to communicate and the delay between a pair of individuals. We have excellent results on a real world dataset from the most popular social networking site, www.myspace.com. We observe interestingly that while context can reasonably predict intent, delay seems to be more dependent on the personal contextual changes and other latent factors characterizing communication, e.g. 'age' of information transmitted and presence of cliques among people.","Title: Major life changes and behavioral markers in social media: case of childbirth\nYear: 2013\n\nAbstract: We explore the harnessing of social media as a window on changes around major life events in individuals and larger populations. We specifically examine patterns of activity, emotional, and linguistic correlates for childbirth and postnatal course. After identifying childbirth events on Twitter, we analyze daily posting patterns and language usage before and after birth by new mothers, and make inferences about the status and dynamics of changes in emotions expressed following childbirth. We find that childbirth is associated with some changes for most new mothers, but approximately 15% of new mothers show significant changes in their online activity and emotional expression postpartum. We observe that these mothers can be distinguished by linguistic changes captured by shifts in a relatively small number of words in their social media posts. We introduce a greedy differencing procedure to identify the type of language that characterizes significant changes in these mothers during postpartum. We conclude with a discussion about how such characterizations might be applied to recognizing and understanding health and well-being in women following childbirth.","Title: Constructing travel itineraries from tagged geo-temporal breadcrumbs\nYear: 2010\n\nAbstract: Vacation planning is a frequent laborious task which requires skilled interaction with a multitude of resources. This paper develops an end-to-end approach for constructing intra-city travel itineraries automatically by tapping a latent source reflecting geo-temporal breadcrumbs left by millions of tourists. In particular, the popular rich media sharing site, Flickr, allows photos to be stamped by the date and time of when they were taken, and be mapped to Points Of Interest (POIs) by latitude-longitude information as well as semantic metadata (e.g., tags) that describe them. Our extensive user study on a \"crowd-sourcing\" marketplace (Amazon Mechanical Turk), indicates that high quality itineraries can be automatically constructed from Flickr data, when compared against popular professionally generated bus tours.","Title: Multi-scale characterization of social network dynamics in the blogosphere\nYear: 2008\n\nAbstract: We have developed a computational framework to characterize social network dynamics in the blogosphere at individual, group and community levels. Such characterization could be used by corporations to help drive targeted advertising and to track the moods and sentiments of consumers. We tested our model on a widely read technology blog called Engadget. Our results show that communities transit between states of high and low entropy, depending on sentiments (positive / negative) about external happenings. We also propose an innovative method to establish the utility of the extracted knowledge, by correlating the mined knowledge with an external time series data (the stock market). Our validation results show that the characterized groups exhibit high stock market movement predictability (89%) and removal of 'impactful' groups makes the community less resilient by lowering predictability (26%) and affecting the composition of the groups in the rest of the community.","Title: How Does the Data Sampling Strategy Impact the Discovery of Information Diffusion in Social Media?\nYear: 2010\n\nAbstract: Platforms such as Twitter have provided researchers with ample opportunities to analytically study social phenomena. There are however, significant computational challenges due to the enormous rate of production of new information: re- searchers are therefore, often forced to analyze a judiciously selected \"sample\" of the data. Like other social media phe- nomena, information diffusion is a social process-it is af- fected by user context, and topic, in addition to the graph topology. This paper studies the impact of different attribute and topology based sampling strategies on the discovery of an important social media phenomena-information diffusion. We examine several widely-adopted sampling methods that select nodes based on attribute (random, location, and activ- ity) and topology (forest fire) as well as study the impact of attribute based seed selection on topology based sampling. Then we develop a series of metrics for evaluating the quality of the sample, based on user activity (e.g. volume, number of seeds), topological (e.g. reach, spread) and temporal char- acteristics (e.g. rate). We additionally correlate the diffusion volume metric with two external variables-search and news trends. Our experiments reveal that for small sample sizes (30%), a sample that incorporates both topology and user- context (e.g. location, activity) can improve on na¨ ive meth- ods by a significant margin of ∼15-20%.","Title: Automatic construction of travel itineraries using social breadcrumbs\nYear: 2010\n\nAbstract: Vacation planning is one of the frequent---but nonetheless laborious---tasks that people engage themselves with online; requiring skilled interaction with a multitude of resources. This paper constructs intra-city travel itineraries automatically by tapping a latent source reflecting geo-temporal breadcrumbs left by millions of tourists. For example, the popular rich media sharing site, Flickr, allows photos to be stamped by the time of when they were taken and be mapped to Points Of Interests (POIs) by geographical (i.e. latitude-longitude) and semantic (e.g., tags) metadata. Leveraging this information, we construct itineraries following a two-step approach. Given a city, we first extract photo streams of individual users. Each photo stream provides estimates on where the user was, how long he stayed at each place, and what was the transit time between places. In the second step, we aggregate all user photo streams into a POI graph. Itineraries are then automatically constructed from the graph based on the popularity of the POIs and subject to the user's time and destination constraints. We evaluate our approach by constructing itineraries for several major cities and comparing them, through a \"crowd-sourcing\" marketplace (Amazon Mechanical Turk), against itineraries constructed from popular bus tours that are professionally generated. Our extensive survey-based user studies over about 450 workers on AMT indicate that high quality itineraries can be automatically constructed from Flickr data.","Title: Computational social science: CSCW in the social media era\nYear: 2014\n\nAbstract: With the widespread proliferation of social media tools such as Facebook and Twitter, the CSCW community has seen a growing interest among researchers to turn to records of social behavior from blogs, social media, and social networking sites, to study human social behavior. This nascent area, that has begun to be referred to in various research circles as \\\"computational social science\\\", provides an exciting and promising development in the CSCW community. This panel brings together a host of researchers with varied disciplinary perspectives to investigate the potential and current state-of-the-art, as well as forthcoming challenges, practical and methodological issues that engender this emerging topic.","Title: Can social media help us reason about mental health?\nYear: 2014\n\nAbstract: Millions of people each year suffer from depression, which makes mental illness one of the most serious and widespread health challenges in our society today. There is therefore a need for effective policies, interventions, and prevention strategies that enable early detection and diagnosis of mental health concerns in populations. This talk reports some findings on the potential of leveraging social media postings as a new type of lens in understanding mental illness in individuals and populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements of behavior over time while radically expanding population sample sizes. The talk highlights how this research direction may be useful in developing tools for identifying the onset of depressive disorders, for use by healthcare agencies; or on behalf of individuals, enabling those suffering from mental illness to be more proactive about their mental health.","Title: \"Birds of a Feather\": Does User Homophily Impact Information Diffusion in Social Media?\nYear: 2010\n\nAbstract: This article investigates the impact of user homophily on the social process\nof information diffusion in online social media. Over several decades, social\nscientists have been interested in the idea that similarity breeds connection:\nprecisely known as \"homophily\". Homophily has been extensively studied in the\nsocial sciences and refers to the idea that users in a social system tend to\nbond more with ones who are similar to them than to ones who are dissimilar.\nThe key observation is that homophily structures the ego-networks of\nindividuals and impacts their communication behavior. It is therefore likely to\neffect the mechanisms in which information propagates among them. To this\neffect, we investigate the interplay between homophily along diverse user\nattributes and the information diffusion process on social media. In our\napproach, we first extract diffusion characteristics---corresponding to the\nbaseline social graph as well as graphs filtered on different user attributes\n(e.g. location, activity). Second, we propose a Dynamic Bayesian Network based\nframework to predict diffusion characteristics at a future time. Third, the\nimpact of attribute homophily is quantified by the ability of the predicted\ncharacteristics in explaining actual diffusion, and external variables,\nincluding trends in search and news. Experimental results on a large Twitter\ndataset demonstrate that choice of the homophilous attribute can impact the\nprediction of information diffusion, given a specific metric and a topic. In\nmost cases, attribute homophily is able to explain the actual diffusion and\nexternal trends by ~15-25% over cases when homophily is not considered.","Title: Understanding affect in the workplace via social media\nYear: 2013\n\nAbstract: We investigate the landscape of affective expression of employees at a large Fortune 500 software corporation via an internal microblogging tool. We present three analyses of emotional expression among employees, based on literature in organizational behavior: its relationship to (1) exogenous/lifestyle and endogenous workplace factors, (2) geography and (3) organizational structure. We find that employees tend to make significant accommodations in affect expression when interacting with others over the organizational hierarchy. We also find that positive affect is expressed through interpersonal communications that connect disparate geographic regions. Our findings have implications for enabling emotional reflection of employees and for management in that they can help uncover emotional patterns associated with episodes of high and low productivity, allowing organizations to improve employee engagement and promote positive attitudes.","Title: Tie Formation on Twitter: Homophily and Structure of Egocentric Networks\nYear: 2011\n\nAbstract: Both homophily and tie formation remain well studied problems in the social sciences literature since several decades. Prior empirical work on networks seems to indicate that in several situations, high degree of homophily was observed to be behind an individual's desire to establish new ties. However in the context of today's social media, not all individuals are the same, topologically. That is, we observe a variety of ego network structures based on individuals' inlink-outlink relationships. In the context of tie formation in these networks, do different ego network topologies exhibit homophily along different attributes? How can we quantify and investigate these differences? To this end, we propose a variety of attributes along which homophily can be measured between individuals: including demographic attributes, activity-specific attributes and content-based attributes. We further categorize ego network structures as generators, mediators and receptors based on a measure called ego ratio. In our experiments on a large Twitter dataset comprising about 29.5M tweets, we observe, somewhat surprisingly, that for a few attributes, there was consistently high homophily (topical interest)/low homophily (gender, ethnicity) regardless of the ego network structure. Otherwise, mediators were observed to associate tie formation extensively with location, interactive ness and sentiment homophily, whereas generators were driven largely by information broadcasting behavior homophily. Implications of the findings in understanding the diverse range of motivations behind user participation in social media sites are discussed.","Title: Multimedia Semantics: Interactions Between Content and Community.\nYear: 2012\n\nAbstract: This paper reviews the state of the art and some emerging issues in research areas related to pattern analysis and monitoring of web-based social communities. This research area is important for several reasons. First, the presence of near-ubiquitous low-cost computing and communication technologies has enabled people to access and share information at an unprecedented scale. The scale of the data...","Title: What makes conversations interesting?: themes, participants and consequences of conversations in online social media\nYear: 2009\n\nAbstract: Rich media social networks promote not only creation and consumption of media, but also communication about the posted media item. What causes a conversation to be interesting, that prompts a user to participate in the discussion on a posted video? We conjecture that people participate in conversations when they find the conversation theme interesting, see comments by people whom they are familiar with, or observe an engaging dialogue between two or more people (absorbing back and forth exchange of comments). Importantly, a conversation that is interesting must be consequential - i.e. it must impact the social network itself. Our framework has three parts: characterizing themes, characterizing participants for determining interestingness and measures of consequences of a conversation deemed to be interesting. First, we detect conversational themes using a mixture model approach. Second, we determine interestingness of participants and interestingness of conversations based on a random walk model. Third, we measure the consequence of a conversation by measuring how interestingness affects the following three variables - participation in related themes, participant cohesiveness and theme diffusion. We have conducted extensive experiments using dataset from the popular video sharing site, YouTube. Our results show that our method of interestingness maximizes the mutual information, and is significantly better (twice as large) than three other baseline methods (number of comments, number of new participants and PageRank based assessment).","Title: Predicting postpartum changes in emotion and behavior via social media\nYear: 2013\n\nAbstract: We consider social media as a promising tool for public health, focusing on the use of Twitter posts to build predictive models about the forthcoming influence of childbirth on the behavior and mood of new mothers. Using Twitter posts, we quantify postpartum changes in 376 mothers along dimensions of social engagement, emotion, social network, and linguistic style. We then construct statistical models from a training set of observations of these measures before and after the reported childbirth, to forecast significant postpartum changes in mothers. The predictive models can classify mothers who will change significantly following childbirth with an accuracy of 71%, using observations about their prenatal behavior, and as accurately as 80-83% when additionally leveraging the initial 2-3 weeks of postnatal data. The study is motivated by the opportunity to use social media to identify mothers at risk of postpartum depression, an underreported health concern among large populations, and to inform the design of low-cost, privacy-sensitive early-warning systems and intervention programs aimed at promoting wellness postpartum.","Title: Social media as a measurement tool of depression in populations\nYear: 2013\n\nAbstract: Depression is a serious and widespread public health challenge. We examine the potential for leveraging social media postings as a new type of lens in understanding depression in populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements over time while radically expanding population sample sizes. We present work on using a crowdsourcing methodology to build a large corpus of postings on Twitter that have been shared by individuals diagnosed with clinical depression. Next, we develop a probabilistic model trained on this corpus to determine if posts could indicate depression. The model leverages signals of social activity, emotion, and language manifested on Twitter. Using the model, we introduce a social media depression index that may serve to characterize levels of depression in populations. Geographical, demographic and seasonal patterns of depression given by the measure confirm psychiatric findings and correlate highly with depression statistics reported by the Centers for Disease Control and Prevention (CDC).","Title: Understanding Community Dynamics in Online Social Networks: A multidisciplinary review.\nYear: 2012\n\nAbstract: Social network systems are significant scaffolds for political, economic, and sociocultural change. This is in part due to the widespread availability of sophisticated network technologies and the concurrent emergence of rich media Web sites. Social network sites provide new opportunities for social-technological research. Since we can inexpensively collect electronic records (over extended period...","Title: Social Synchrony: Predicting Mimicry of User Actions in Online Social Media\nYear: 2009\n\nAbstract: We propose a computational framework to predict synchronyof action in online social media. Synchrony is a temporalsocial network phenomenon in which a large number of usersare observed to mimic a certain action over a period of timewith sustained participation from early users.Understanding social synchrony can be helpful in identifyingsuitable time periods of viral marketing. Our method consistsof two parts – the learning framework and the evolutionframework. In the learning framework, we develop a DBNbased representation that includes an understanding of usercontext to predict the probability of user actions over a set oftime slices into the future. In the evolution framework, weevolve the social network and the user models over a set offuture time slices to predict social synchrony. Extensiveexperiments on a large dataset crawled from the popularsocial media site Digg (comprising ~7M diggs) show thatour model yields low error (15.2+4.3%) in predicting useractions during periods with and without synchrony.Comparison with baseline methods indicates that our methodshows significant improvement in predicting user actions.","Title: Role of social media in tackling challenges in mental health\nYear: 2013\n\nAbstract: Mental illness is a serious and widespread health challenge in our society today. Tens of millions of people each year suffer from depression and only a fraction receives adequate treatment. This position paper highlights some recent attempts examining the potential for leveraging social media postings as a new type of lens in understanding mental illness in individuals and populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements of behavior over time while radically expanding population sample sizes. We conclude highlighting how this research direction may be useful in developing tools for identifying the onset of depressive disorders in individuals, for use by healthcare agencies; or on behalf of individuals, enabling those suffering from mental illness to be more proactive about their mental health.","Title: Contextual Prediction of Communication Flow in Social Networks\nYear: 2007\n\nAbstract: The paper develops a novel computational framework for predicting communication flow in social networks based on several contextual features. The problem is important because prediction of communication flow can impact timely sharing of specific information across a wide array of communities. We determine the intent to communicate and communication delay between users based on several contextual features in a social network corresponding to (a) neighborhood context, (b) topic context and (c) recipient context. The intent to communicate and communication delay are modeled as regression problems which are efficiently estimated using Support Vector Regression. We predict the intent and the delay, on an interval of time using past communication data. We have excellent prediction results on a real-world dataset from MySpace.com with an accuracy of 13-16%. We show that the intent to communicate is more significantly influenced by contextual factors compared to the delay.","Title: The new war correspondents: the rise of civic media curation in urban warfare\nYear: 2013\n\nAbstract: In this paper we examine the information sharing practices of people living in cities amid armed conflict. We describe the volume and frequency of microblogging activity on Twitter from four cities afflicted by the Mexican Drug War, showing how citizens use social media to alert one another and to comment on the violence that plagues their communities. We then investigate the emergence of civic media \\\"curators,\\\" individuals who act as \\\"war correspondents\\\" by aggregating and disseminating information to large numbers of people on social media. We conclude by outlining the implications of our observations for the design of civic media systems in wartime.","Title: Extraction, characterization and utility of prototypical communication groups in the blogosphere\nYear: 2010\n\nAbstract: This article analyzes communication within a set of individuals to extract the representative prototypical groups and provides a novel framework to establish the utility of such groups. Corporations may want to identify representative groups (which are indicative of the overall communication set) because it is easier to track the prototypical groups rather than the entire set. This can be useful for advertising, identifying “hot” spots of resource consumption as well as in mining representative moods or temperature of a community. Our framework has three parts: extraction, characterization, and utility of prototypical groups. First, we extract groups by developing features representing communication dynamics of the individuals. Second, to characterize the overall communication set, we identify a subset of groups within the community as the prototypical groups. Third, we justify the utility of these prototypical groups by using them as predictors of related external phenomena; specifically, stock market movement of technology companies and political polls of Presidential candidates in the 2008 U.S. elections. We have conducted extensive experiments on two popular blogs, Engadget and Huffington Post. We observe that the prototypical groups can predict stock market movement/political polls satisfactorily with mean error rate of 20.32%. Further, our method outperforms baseline methods based on alternative group extraction and prototypical group identification methods. We evaluate the quality of the extracted groups based on their conductance and coverage measures and develop metrics: predictivity and resilience to evaluate their ability to predict a related external time-series variable (stock market movement/political polls). This implies that communication dynamics of individuals are essential in extracting groups in a community, and the prototypical groups extracted by our method are meaningful in characterizing the overall communication sets.","Title: Context Aware Routing of Enterprise User Communications\nYear: 2007\n\nAbstract: This paper develops a context aware framework to address the diverse communication needs of a modern enterprise. Such enterprises are characterized by workers in different locations, subject to different policies, using different communication devices, and having varying degrees of skill sets. This diversity poses challenges in finding the most effective human worker (agent) for tasks like fielding a customer request, helping another agent with additional expert knowledge, or more generally help complete a task like a supply chain exception. We focus on the problem of routing communications to the most effective agent using a spectrum of contextual knowledge: availability, media type, activity, expertise, and location. We determine an optimal \"request-to-agent' routing based on several metrics of effectiveness depending on the communication context. The optimal agent is selected to communicate on a specific media who minimizes the expected duration of interaction while maximizes the probability of successful call completion. Based on our model we have conducted simulations involving context aware and non-context aware routing scenarios. The results indicate that the context aware routing outperforms other conventional request-routing techniques. The work presented here can impact routing algorithms, as well as address problems related to enterprise staffing and temporal variation of context for the agent.","Title: Smart societies: from citizens as sensors to collective action\nYear: 2013\n\nAbstract: Social media has become globally ubiquitous, transforming how people are networked and mobilized. This forum explores research and applications of these new networked publics at individual, organizational, and societal levels. Shelly Farnham, Editor","Title: Unfolding the event landscape on twitter: classification and exploration of user categories\nYear: 2012\n\nAbstract: Social media platforms such as Twitter garner significant attention from very large audiences in response to real-world events. Automatically establishing who is participating in information production or conversation around events can improve event content consumption, help expose the stakeholders in the event and their varied interests, and even help steer subsequent coverage of an event by journalists. In this paper, we take initial steps towards building an automatic classifier for user types on Twitter, focusing on three core user categories that are reflective of the information production and consumption processes around events: organizations, journalists/media bloggers, and ordinary individuals. Exploration of the user categories on a range of events shows distinctive characteristics in terms of the proportion of each user type, as well as differences in the nature of content each shared around the events.","Title: Temporal patterns in social media streams: Theme discovery and evolution using joint analysis of content and context\nYear: 2009\n\nAbstract: Online social networking sites such as Flickr and Facebook provide a diverse range of functionalities that foster online communities to create and share media content. In particular, Flickr groups are increasingly used to aggregate and share photos about a wide array of topics or themes. Unlike photo repositories where images are typically organized with respect to static topics, the photo sharing process as in Flickr often results in complex time-evolving social and visual patterns. Characterizing such time-evolving patterns can enrich media exploring experience in a social media repository. In this paper, we propose a novel framework that characterizes distinct time-evolving patterns of group photo streams. We use a nonnegative joint matrix factorization approach to incorporate image content features and contextual information, including associated tags, photo owners and post times. In our framework, we consider a group as a mixture of themes - each theme exhibits similar patterns of image content and context. The theme extraction is to best explain the observed image content features and associations with tags, users and times. Extensive experiments on a Flickr dataset suggest that our approach is able to extract meaningful evolutionary patterns from group photo streams. We evaluate our method through a tag prediction task. Our prediction results outperform baseline methods, which indicate the utility of our theme based joint analysis.","Title: Creepy but inevitable?: the evolution of social networking\nYear: 2014\n\nAbstract: This paper focuses on the fifth year of a cross-sectional trend study of enterprise social networking. Several stable patterns are evident--some activities have plateaued, others steadily increase in frequency. The fifth year did see a new development: As social networking companies visibly embraced behavior tracking and targeted advertising, concerns shifted from boundary regulation within personal networks to unsettling evidence of activity monitoring. However, benefits of use continue to outweigh drawbacks.","Title: Seeking and sharing health information online: comparing search engines and social media\nYear: 2014\n\nAbstract: Search engines and social media are two of the most com-monly used online services; in this paper, we examine how users appropriate these platforms for online health activi-ties via both large-scale log analysis and a survey of 210 people. While users often turn to search engines to learn about serious or highly stigmatic conditions, a surprising amount of sensitive health information is also sought and shared via social media, in our case the public social plat-form Twitter. We contrast what health content people seek via search engines vs. share on social media, as well as why they choose a particular platform for online health activi-ties. We reflect on the implications of our results for design-ing search engines, social media, and social search tools that better support people's health information seeking and sharing needs.","Title: Modeling and predicting group activity over time in online social media\nYear: 2009\n\nAbstract: This paper develops a probabilistic framework that can model and predict group activity over time on online social media. Users of social media sites such as Flickr often face the enormous challenge of which group to choose, due to the presence of numerous competing groups of similar content. Determining an empirical measure of significance of a group can help tackle this problem. The proposed framework therefore determines an optimal measure per group based on past user participation and interaction as well as likely future activity in the group. The framework is tested on a Flickr dataset and the results show that this method can yield satisfactory predictions of group activity. This implies that the computed measure of significance of a group can be used by end users to choose groups with rich activity.","Title: Detecting and Characterizing Mental Health Related Self-Disclosure in Social Media\nYear: 2015\n\nAbstract: Self-disclosure is an important element facilitating improved psychological wellbeing in individuals with mental illness. As social media is increasingly adopted in health related discourse, we examine how these new platforms might be allowing honest and candid expression of thoughts, experiences and beliefs. Specifically, we seek to detect levels of self-disclosure manifested in posts shared on different mental health forums on Reddit. We develop a classifier for the purpose based on content features. The classifier is able to characterize a Reddit post to be of high, low, or no self-disclosure with 78% accuracy. Applying this classifier to general mental health discourse on Reddit, we find that bulk of such discourse is characterized by high self-disclosure, and that the community responds distinctively to posts that disclose less or more. We conclude with the potential of harnessing our proposed self-disclosure detection algorithm in psychological therapy via social media. We also discuss design considerations for improved community moderation and support in these vulnerable self-disclosing communities.","Title: Anorexia on Tumblr: A Characterization Study\nYear: 2015\n\nAbstract: Eating disorders, such as anorexia nervosa are a major health concern affecting many young individuals. Given the extensive adoption of social media technologies in the anorexia affected demographic, we study behavioral characteristics of this population focusing on the social media Tumblr. Aligned with observations in prior literature, we find the presence of two prominent anorexia related communities on Tumblr -- pro-anorexia and pro-recovery. Empirical analyses on several thousand Tumblr posts show use of the site as a media-rich platform replete with triggering content for enacting anorexia as a lifestyle choice. Through use of common pro-anorexia tags, the pro-recovery community however attempts to \\\"permeate\\\" into the pro-anorexia community to educate them of the health risks of anorexia. Further, the communities exhibit distinctive affective, social, cognitive, and linguistic style markers. Compared with recover- ing anorexics, pro-anorexics express greater negative affect, higher cognitive impairment, and greater feelings of social isolation and self-harm. We also observe that these characteristics may be used in a predictive setting to detect anorexia content with 80% accuracy. Based on our findings, clinical implications of detecting anorexia related content on social media are discussed.","Title: Quote RTs on Twitter: Usage of the New Feature for Political Discourse.\nYear: 2016\n\nAbstract: Social media platforms provide several social interactional features. Due to the large scale reach of social media, these interactional features help enable various types of political discourse. Constructive and diversified discourse is important for sustaining healthy communities and reducing the impact of echo chambers. In this paper, we empirically examine the role of a newly introduced Twitter feature, 'quote retweets' (or 'quote RTs') in political discourse, specifically whether it has led to improved, civil, and balanced exchange. Quote RTs allow users to quote the tweet they retweet, while adding a short comment. Our analysis using content, network and crowd labeled data indicates that the feature has increased political discourse and its diffusion, compared to existing features. We discuss the implications of our findings in understanding and reducing online polarization.","Title: Psychological Effects of Urban Crime Gleaned from Social Media\nYear: 2015\n\nAbstract: Exposure to frequent crime incidents has been found to have a negative bearing on the well-being of city residents, even if they are not themselves a direct victim. We pursue the research question of whether naturalistic data shared on Twitter may provide a \"lens\" to understand changes in psychological attributes of urban communities (1) immediately following crime incidents, as well as (2) due to long-term exposure to crime. We analyze half a million Twitter posts from the City of Atlanta in 2014, where the rate of violent crime is three times of the national average. In a first study, we develop a statistical method to detect changes in social media psychological attributes in the immediate aftermath of a crime event. Second, we develop a regression model that uses historical (yearlong) crime to predict Twitter negative emotion, anxiety, anger, and sadness. We do not find significant changes in social media affect immediately following crime in Atlanta. However we do observe significant ability of historical crime to account for heightened negative emotion and anger in the future. Our findings have implications in gauging the utility of social media to infer longitudinal and population-scale patterns of urban well-being.","Title: Measuring and Characterizing Nutritional Information of Food and Ingestion Content in Instagram\nYear: 2015\n\nAbstract: Social media sites like Instagram have emerged as popular platforms for sharing ingestion and dining experiences. However research on characterizing the nutritional information embedded in such content is limited. In this paper, we develop a computational method to extract nutritional information, specifically calorific content from Instagram food posts. Next, we explore how the community reacts specifically to healthy versus non-healthy food postings. Based on a crowdsourced approach, our method was found to detect calorific content in posts with 89% accuracy. We further show the use of Instagram as a platform where sharing of moderately healthy food content is common, and such content also receives the most support from the community.","Title: Identity Management and Mental Health Discourse in Social Media\nYear: 2015\n\nAbstract: Social media is increasingly being adopted in health discourse. We examine the role played by identity in supporting discourse on socially stigmatized conditions. Specifically, we focus on mental health communities on reddit. We investigate the characteristics of mental health discourse manifested through reddit's characteristic 'throwaway' accounts, which are used as proxies of anonymity. For the purpose, we propose affective, cognitive, social, and linguistic style measures, drawing from literature in psychology. We observe that mental health discourse from throwaways is considerably disinhibiting and exhibits increased negativity, cognitive bias and self-attentional focus, and lowered self-esteem. Throwaways also seem to be six times more prevalent as an identity choice on mental health forums, compared to other reddit communities. We discuss the implications of our work in guiding mental health interventions, and in the design of online communities that can better cater to the needs of vulnerable populations. We conclude with thoughts on the role of identity manifestation on social media in behavioral therapy.","Title: #thyghgapp: Instagram Content Moderation and Lexical Variation in Pro-Eating Disorder Communities.\nYear: 2016\n\nAbstract: Pro-eating disorder (pro-ED) communities on social media encourage the adoption and maintenance of disordered eating habits as acceptable alternative lifestyles rather than threats to health. In particular, the social networking site Instagram has reacted by banning searches on several pro-ED tags and issuing content advisories on others. We pre-sent the first large-scale quantitative study investigating pro-ED communities on Instagram in the aftermath of moderation -- our dataset contains 2.5M posts between 2011 and 2014. We find that the pro-ED community has adopted non-standard lexical variations of moderated tags to circumvent these restrictions. In fact, increasingly complex lexical variants have emerged over time. Communities that use lexical variants show increased participation and support of pro-ED (15-30%). Finally, the tags associated with content on these variants express more toxic, self-harm, and vulnerable content. Despite Instagramâs moderation strategies, pro-ED communities are active and thriving. We discuss the effectiveness of content moderation as an intervention for communities of deviant behavior.","Title: Characterizing Dietary Choices, Nutrition, and Language in Food Deserts via Social Media.\nYear: 2016\n\nAbstract: Social media has emerged as a promising source of data for public health. This paper examines how these platforms can provide empirical quantitative evidence for understanding dietary choices and nutritional challenges in “food deserts” -- Census tracts characterized by poor access to healthy and affordable food. We present a study of 3 million food related posts shared on Instagram, and observe that content from food deserts indicate consumption of food high in fat, cholesterol and sugar; a rate higher by 5-17% compared to non-food desert areas. Further, a topic model analysis reveals the ingestion language of food deserts to bear distinct attributes. Finally, we investigate to what extent Instagram ingestion language is able to infer whether a tract is a food desert. We find that a predictive model that uses ingestion topics, socio-economic and food deprivation status attributes yields high accuracy (u003e80%) and improves over baseline methods by 6-14%. We discuss the role of social media in helping address inequalities in food access and health.","Title: Quantifying and Predicting Mental Illness Severity in Online Pro-Eating Disorder Communities.\nYear: 2016\n\nAbstract: Social media sites have struggled with the presence of emotional and physical self-injury content. Individuals who share such content are often challenged with severe mental illnesses like eating disorders. We present the first study quantifying levels of mental illness severity (MIS) in social media. We examine a set of users on Instagram who post content on pro-eating disorder tags (26M posts from 100K users). Our novel statistical methodology combines topic modeling and novice/clinician annotations to infer MIS in a userâ s content. Alarmingly, we find that proportion of users whose content expresses high MIS have been on the rise since 2012 (13%/year increase). Previous MIS in a userâ s content over seven months can predict future risk with 81% accuracy. Our model can also forecast MIS levels up to eight months in the future with performance better than baseline. We discuss the health outcomes and design implications as well as ethical considerations of this line of research.","Title: Social Media for Mental Illness Risk Assessment, Prevention and Support\nYear: 2015\n\nAbstract: Social media sites are continually creating rich repositories of information relating to our activities, emotion and linguistic expression. In this talk I will discuss how such trails of data may be harnessed to reason about our mental health concerns. First, I will discuss a series of studies that examined how cues derived from social media around major life events (e.g., childbirth) and societal disruptions (e.g., violence) may help infer risks to well-being. Second, I will discuss threads of research in which we investigated the role of social media systems in providing a platform of expression to distressed communities and communities exhibiting deviant health behaviors. Broadly, I will reflect on how this new line of research bears potential in informing the design of interventions for improved well-being, privacy and ethical considerations, and in this context, the challenges and opportunities of the increasing ubiquity of social media.","Title: Detecting Changes in Suicide Content Manifested in Social Media Following Celebrity Suicides\nYear: 2015\n\nAbstract: The Werther effect describes the increased rate of completed or attempted suicides following the depiction of an individual's suicide in the media, typically a celebrity. We present findings on the prevalence of this effect in an online platform: r/SuicideWatch on Reddit. We examine both the posting activity and post content after the death of ten high-profile suicides. Posting activity increases following reports of celebrity suicides, and post content exhibits considerable changes that indicate increased suicidal ideation. Specifically, we observe that post-celebrity suicide content is more likely to be inward focused, manifest decreased social concerns, and laden with greater anxiety, anger, and negative emotion. Topic model analysis further reveals content in this period to switch to a more derogatory tone that bears evidence of self-harm and suicidal tendencies. We discuss the implications of our findings in enabling better community support to psychologically vulnerable populations, and the potential of building suicide prevention interventions following high-profile suicides.","Title: Characterizing Smoking and Drinking Abstinence from Social Media.\nYear: 2015\n\nAbstract: Social media has been established to bear signals relating to health and well-being states. In this paper, we investigate the potential of social media in characterizing and understanding abstinence from tobacco or alcohol use. While the link between behavior and addiction has been explored in psychology literature, the lack of longitudinal self-reported data on long-term abstinence has challenged addiction research. We leverage the activity spanning almost eight years on two prominent communities on Reddit: StopSmoking and StopDrinking. We use the self-reported \"badge\" information of nearly a thousand users as gold standard information on their abstinence status to characterize long-term abstinence. We build supervised learning based statistical models that use the linguistic features of the content shared by the users as well as the network structure of their social interactions. Our findings indicate that long-term abstinence from smoking or drinking (~one year) can be distinguished from short-term abstinence (~40 days) with 85% accuracy. We further show that language and interaction on social media offer powerful cues towards characterizing these addiction-related health outcomes. We discuss the implications of our findings in social media and health research, and in the role of social media as a platform for positive behavior change and therapy.","Title: Understanding Social Media Disclosures of Sexual Abuse Through the Lenses of Support Seeking and Anonymity.\nYear: 2016\n\nAbstract: Support seeking in stigmatized contexts is useful when the discloser receives the desired response, but it also entails social risks. Thus, people do not always disclose or seek support when they need it. One such stigmatized context for support seeking is sexual abuse. In this paper, we use mixed methods to understand abuse-related posts on reddit. First, we take a qualitative approach to understand post content. Then we use quantitative methods to investigate the use of \"throwaway\" accounts, which provide greater anonymity, and report on factors associated with support seeking and first-time disclosures. In addition to significant linguistic differences between throwaway and identified accounts, we find that those using throwaway accounts are significantly more likely to engage in seeking support. We also find that men are significantly more likely to use throwaway accounts when posting about sexual abuse. Results suggest that subreddit moderators and members who wish to provide support pay attention to throwaway accounts, and we discuss the importance of context-specific anonymity in support seeking.","Title: Recovery Amid Pro-Anorexia: Analysis of Recovery in Social Media.\nYear: 2016\n\nAbstract: Online communities can promote illness recovery and improve well-being in the cases of many kinds of illnesses. However, for challenging mental health condition like anorexia, social media harbor both recovery communities as well as those that encourage dangerous behaviors. The effectiveness of such platforms in promoting recovery despite housing both communities is underexplored. Our work begins to fill this gap by developing a statistical framework using survival analysis and situating our results within the cognitive behavioral theory of anorexia. This model identifies content and participation measures that predict the likelihood of recovery. From our dataset of over 68M posts and 10K users that self-identify with anorexia, we find that recovery on Tumblr is protracted - only half of the population is estimated to exhibit signs of recovery after four years. We discuss the effectiveness of social media in improving well-being around anorexia, a unique health challenge, and emergent questions from this line of work.","Title: \"This Post Will Just Get Taken Down\": Characterizing Removed Pro-Eating Disorder Social Media Content.\nYear: 2016\n\nAbstract: Social media sites like Facebook and Instagram remove content that is against community guidelines or is perceived to be deviant behavior. Users also delete their own content that they feel is not appropriate within personal or community norms. In this paper, we examine characteristics of over 30,000 pro-eating disorder (pro-ED) posts that were at one point public on Instagram but have since been removed. Our work shows that straightforward signals can be found in deleted content that distinguish them from other posts, and that the implications of such classification are immense. We build a classifier that compares public pro-ED posts with this removed content that achieves moderate accuracy of 69%. We also analyze the characteristics in content in each of these post categories and find that removed content reflects more dangerous actions, self-harm tendencies, and vulnerability than posts that remain public. Our work provides early insights into content removal in a sensitive community and addresses the future research implications of the findings.","Title: Discovering Shifts to Suicidal Ideation from Mental Health Content in Social Media.\nYear: 2016\n\nAbstract: History of mental illness is a major factor behind suicide risk and ideation. However research efforts toward characterizing and forecasting this risk is limited due to the paucity of information regarding suicide ideation, exacerbated by the stigma of mental illness. This paper fills gaps in the literature by developing a statistical methodology to infer which individuals could undergo transitions from mental health discourse to suicidal ideation. We utilize semi-anonymous support communities on Reddit as unobtrusive data sources to infer the likelihood of these shifts. We develop language and interactional measures for this purpose, as well as a propensity score matching based statistical approach. Our approach allows us to derive distinct markers of shifts to suicidal ideation. These markers can be modeled in a prediction framework to identify individuals likely to engage in suicidal ideation in the future. We discuss societal and ethical implications of this research.","Title: Social Media Participation in an Activist Movement for Racial Equality.\nYear: 2016\n\nAbstract: From the Arab Spring to the Occupy Movement, social media has been instrumental in driving and supporting socio-political movements throughout the world. In this paper, we present one of the first social media investigations of an activist movement around racial discrimination and police violence, known as \"Black Lives Matter\". Considering Twitter as a sensor for the broader community's perception of the events related to the movement, we study participation over time, the geographical differences in this participation, and its relationship to protests that unfolded on the ground. We find evidence for continued participation across four temporally separated events related to the movement, with notable changes in engagement and language over time. We also find that participants from regions of historically high rates of black victimization due to police violence tend to express greater negativity and make more references to loss of life. Finally, we observe that social media attributes of affect, behavior and language can predict future protest participation on the ground. We discuss the role of social media in enabling collective action around this unique movement and how social media platforms may help understand perceptions on a socially contested and sensitive issue like race.","Title: Opportunities and Challenges of Social Media in Personal and Societal Well-being\nYear: 2016\n\nAbstract: Social media platforms have emerged as rich repositories of information relating to our activities, emotion and linguistic expression. In this talk I will discuss how this data may be harnessed to reason about our well-being. First, I will discuss a series of projects that examine how cues derived from social media around life-altering events (e.g., giving birth to a child, experience of abuse) and societal disruptions (e.g., urban violence, socio-political unrest) may help infer risks to mental health challenges. Second, I will discuss the emergent role of social media in providing a platform of self-disclosure and support to distressed, vulnerable, and under-privileged communities. Broadly, I will reflect on how this new line of research bears potential in informing the design of timely and tailored interventions, provisions for improved personal and societal well-being assessment, privacy and ethical considerations, and in this context, the challenges and opportunities of the increasing ubiquity of social media.","Title: Social Media for Safety: Characterizing Online Interactions Between Citizens and Police.\nYear: 2016\n\nAbstract: Social media has emerged as a promising resource for police to connect with citizens for collective action. However the attributes of police citizen interactions on social media remain under-explored. In this paper, we utilise official and public Facebook pages of several police departments in India to study the patterns of engagement, emotions, and social processes between citizens and police in the context of day-to-day policing. We examine two prominent discussion threads: police initiated and citizen initiated. We find that topics exchanged in police initiated discussions are more focussed than citizen initiated threads; police focused on topics concerning safety awareness programs, action reports, and information regarding policing activities. Compared to police initiated discussions, citizen initiated discussions show lower engagement. Further, discussions involving both police and citizens show higher negative emotions, anger and arousal than citizen only discussions; these interventions involving both reveal a stronger notion of a collective identity. We discuss the implications of our work in designing technological support for improved policing and to help understand citizen opinions, safety concerns and well-being via social media.","Title: Computational Approaches Toward Integrating Quantified Self Sensing and Social Media.\nYear: 2017\n\nAbstract: The growing amount of data collected by quantified self tools and social media hold great potential for applications in personalized medicine. Whereas the first includes health-related physiological signals, the latter provides insights into a user's behavior. However, the two sources of data have largely been studied in isolation. We analyze public data from users who have chosen to connect their MyFitnessPal and Twitter accounts. We show that a user's diet compliance success, measured via their self-logged food diaries, can be predicted using features derived from social media: linguistic, activity, and social capital. We find that users with more positive affect and a larger social network are more successful in succeeding in their dietary goals. Using a Granger causality methodology, we also show that social media can help predict daily changes in diet compliance success or failure with an accuracy of 77%, that improves over baseline techniques by 17%. We discuss the implications of our work in the design of improved health interventions for behavior change.","Title: Gender and Cross-Cultural Differences in Social Media Disclosures of Mental Illness.\nYear: 2017\n\nAbstract: Cultural and gender norms shape how mental illness and therapy are perceived. However, there is a paucity of adequate empirical evidence around gender and cultural dimensions of mental illness. In this paper we situate social media as a \\\"lens\\\" to examine these dimensions. We focus on a large dataset of individuals who self-disclose to have an underlying mental health concern on Twitter. Having identified genuine disclosures in this data via semi-supervised learning, we examine differences in their posts, as measured via linguistic attributes and topic models. Our findings reveal significant differences between the content shared by female and male users, and by users from two western and two majority world countries. Males express higher negativity and lower desire for social support, whereas majority world users demonstrate more inhibition in their expression. We discuss the implications of our work in providing insights into the relationship of gender and culture with mental health, and in the design of gender and culture-aware health interventions.","Title: A Social Media Based Index of Mental Well-Being in College Campuses.\nYear: 2017\n\nAbstract: Psychological distress in the form of depression, anxiety and other mental health challenges among college students is a growing health concern. Dearth of accurate, continuous, and multi-campus data on mental well-being presents significant challenges to intervention and mitigation efforts in college campuses. We examine the potential of social media as a new \\\"barometer\\\" for quantifying the mental well-being of college populations. Utilizing student-contributed data in Reddit communities of over 100 universities, we first build and evaluate a transfer learning based classification approach that can detect mental health expressions with 97% accuracy. Thereafter, we propose a robust campus-specific Mental Well-being Index: MWI. We find that MWI is able to reveal meaningful temporal patterns of mental well-being in campuses, and to assess how their expressions relate to university attributes like size, academic prestige, and student demographics. We discuss the implications of our work for improving counselor efforts, and in the design of tools that can enable better assessment of the mental health climate of college campuses.","Title: CHI-nnabis: Implications of Marijuana Legalization for and from Human-Computer Interaction.\nYear: 2017\n\nAbstract: The consumption of cannabis has substantial implications for medicine, popular culture, and technology use, yet discussion of it is almost entirely absent in the HCI literature. Taking advantage of CHI 2017's location in one of the first jurisdictions to legalize recreational use of marijuana in the U.S., this panel will discuss its socio-technical implications, identify HCI research themes relevant to policy and public health debates, and outline a research agenda.","Title: Modeling and Understanding Visual Attributes of Mental Health Disclosures in Social Media.\nYear: 2017\n\nAbstract: Content shared on social media platforms has been identified to be valuable in gaining insights into people's mental health experiences. Although there has been widespread adoption of photo-sharing platforms such as Instagram in recent years, the role of visual imagery as a mechanism of self-disclosure is less understood. We study the nature of visual attributes manifested in images relating to mental health disclosures on Instagram. Employing computer vision techniques on a corpus of thousands of posts, we extract and examine three visual attributes: visual features (e.g., color), themes, and emotions in images. Our findings indicate the use of imagery for unique self-disclosure needs, quantitatively and qualitatively distinct from those shared via the textual modality: expressions of emotional distress, calls for help, and explicit display of vulnerability. We discuss the relationship of our findings to literature in visual sociology, in mental health self disclosure, and implications for the design of health interventions.","Title: Multimodal Classification of Moderated Online Pro-Eating Disorder Content.\nYear: 2017\n\nAbstract: Social media sites are challenged by both the scale and variety of deviant behavior online. While algorithms can detect spam and obscenity, behaviors that break community guidelines on some sites are difficult because they have multimodal subtleties (images and/or text). Identifying these posts is often regulated to a few moderators. In this paper, we develop a deep learning classifier that jointly models textual and visual characteristics of pro-eating disorder content that violates community guidelines. Using a million Tumblr photo posts, our classifier discovers deviant content efficiently while also maintaining high recall (85%). Our approach uses human sensitivity throughout to guide the creation, curation, and understanding of this approach to challenging, deviant content. We discuss how automation might impact community moderation, and the ethical and social obligations of this area.","Title: How to Handle Online Risks?: Discussing Content Curation and Moderation in Social Media.\nYear: 2017\n\nAbstract: Amidst proliferation of online negativity and harmful content such as fake news and harassment on social media, this panel will be an active discussion of the potential roles of various actors in sociotechnical systems in curating, moderating, and studying content. Should companies intervene? Why or why not, and if so, to what extent? What role do academics play in this process and how does it affect research processes? Our multidisciplinary panelists represent humanities, computer science, law, and media psychology. They will share perspectives based on their own research and interact with the audience to discuss varied perspectives around these central questions. A primary goal is to think about how, moving forward, these issues affect HCI research.","Title: The Language of Social Support in Social Media and Its Effect on Suicidal Ideation Risk.\nYear: 2017\n\nAbstract: Online social support is known to play a significant role in mental well-being. However, current research is limited in its ability to quantify this link. Challenges exist due to the paucity of longitudinal, pre- and post mental illness risk data, and reliable methods that can examine causality between past availability of support and future risk. In this paper, we propose a method to measure how the language of comments in Reddit mental health communities influences risk to suicidal ideation in the future. Incorporating human assessments in a stratified propensity score analysis based framework, we identify comparable subpopulations of individuals and measure the effect of online social support language. We interpret these linguistic cues with an established theoretical model of social support, and find that esteem and network support play a more prominent role in reducing forthcoming risk. We discuss the implications of our work for designing tools that can improve support provisions in online communities.","Title: Analysis of Smoking and Drinking Relapse in an Online Community.\nYear: 2017\n\nAbstract: Online communities and social media are known to play an important role in improving health efficacy and well-being. In this paper, we examine the role of such platforms in promoting smoking and drinking cessation. We focus on two support communities on Reddit, StopSmoking and StopDrinking, to analyze relapse events among several thousand individuals. For this purpose, we formulate and identify the key engagement and linguistic characteristics of abstainers and relapsers based on participation in the communities spanning almost nine years, and we employ a robust statistical methodology based on survival analysis to examine how participation and these characteristics relate to likelihood of relapse. Our results show that half of the population is at a high risk of relapse within 1-2 months of cessation attempts; however, individuals who continue to abstain beyond three years tend to maintain high likelihood of sustained abstinence. Furthermore, we find positive affect and increased social engagement to be predictors of abstinence. We discuss the implications of our work in tracking effectiveness of online health communities and for designing health interventions.","Title: Inferring Mood Instability on Social Media by Leveraging Ecological Momentary Assessments.\nYear: 2017\n\nAbstract: Active and passive sensing technologies are providing powerful mechanisms to track, model, and understand a range of health behaviors and well-being states. Despite yielding rich, dense and high fidelity data, current sensing technologies often require highly engineered study designs and persistent participant compliance, making them difficult to scale to large populations and to data acquisition tasks spanning extended time periods. This paper situates social media as a new passive, unobtrusive sensing technology. We propose a semi-supervised machine learning framework to combine small samples of data gathered through active sensing, with large-scale social media data to infer mood instability (MI) in individuals. Starting from a theoretically-grounded measure of MI obtained from mobile ecological momentary assessments (EMAs), we show that our model is able to infer MI in a large population of Twitter users with 96% accuracy and F-1 score. Additionally, we show that, our model predicts self-identifying Twitter users with bipolar and borderline personality disorder to exhibit twice the likelihood of high MI, compared to that in a suitable control. We discuss the implications and the potential for integrating complementary sensing capabilities to address complex research challenges in precision medicine.","Title: Norms Matter: Contrasting Social Support Around Behavior Change in Online Weight Loss Communities\nYear: 2018\n\nAbstract: ABSTRACTOnline health communities (OHCs) provide support across conditions; for weight loss, OHCs offer support to foster positive behavior change. However, weight loss behaviors can also be subverted on OHCs to promote disordered eating practices. Using comments as proxies for support, we use computational linguistic methods to juxtapose similarities and differences in two Reddit weight loss communities, r/proED and r/loseit. We employ language modeling and find that word use in both communities is largely similar. Then, by building a word embedding model, specifically a deep neural network on comment words, we contrast the context of word use and find differences that imply different behavior change goals in these OHCs. Finally, these content and context norms predict whether a comment comes from r/proED or r/loseit. We show that norms matter in understanding how different OHCs provision support to promote behavior change and discuss the implications for design and moderation of OHCs.","Title: Mental Health Support and its Relationship to Linguistic Accommodation in Online Communities\nYear: 2018\n\nAbstract: ABSTRACTMany online communities cater to the critical and unmet needs of individuals challenged with mental illnesses. Generally, communities engender characteristic linguistic practices, known as norms. Conformance to these norms, or linguistic accommodation, encourages social approval and acceptance. This paper investigates whether linguistic accommodation impacts a specific social feedback: the support received by an individual in an online mental health community. We first quantitatively derive two measures for each post in these communities: 1) the linguistic accommodation it exhibits, and 2) the level of support it receives. Thereafter, we build a statistical framework to examine the relationship between these measures. Although the extent to which accommodation is associated with support varies, we find a positive link between the two, consistent across 55 Reddit communities serving various psychological needs. We discuss how our work surfaces a tension in the functioning of these sensitive communities, and present design implications for improving their support provisioning mechanisms.","Title: Relationship breakup disclosures and media ideologies on Facebook.\nYear: 2018\n\nAbstract: After relationship breakups, people must make difficult decisions about whether and how to convey this change in a networked environment. To understand and characterize behaviors around breakup disclosures, we analyzed survey responses from 119 US Facebook users who reported experiencing a recent breakup. Using mixed methods, we find that those perceiving Facebook as a more efficient disclosure medium are more likely to announce breakups. We show how media ideologies around Facebook breakup disclosures vary; yet people assume others hold similar beliefs about what is appropriate. We contribute to self-disclosure and online identity literature by identifying two new ways people engage in disclosure and self-presentation on social media: announcements, which highlight how social media can serve as efficient one-to-many disclosure sources, and private status change behaviors, a reflexive means of self-presentation. Understanding breakup disclosures provides insight into designing social media to better enable users to find support during difficult life transitions.","Title: A Social Media Based Examination of the Effects of Counseling Recommendations after Student Deaths on College Campuses.\nYear: 2018\n\nAbstract: Student deaths on college campuses, whether brought about by a suicide or an uncontrollable incident, have serious repercussions for the mental wellbeing of students. Consequently, many campus administrators implement post-crisis intervention measures to promote student-centric mental health support. Information about these measures, which we refer to as \"\", are often shared via electronic channels, including social media. However, the current ability to assess the effects of these recommendations on post-crisis psychological states is limited. We propose a causal analysis framework to examine the effects of these counseling recommendations after student deaths. We leverage a dataset from 174 Reddit campus communities and ~400M posts of ~350K users. Then we employ statistical modeling and natural language analysis to quantify the psychosocial shifts in behavioral, cognitive, and affective expression of grief in individuals who are \"exposed\" to (comment on) the counseling recommendations, compared to that in a matched control cohort. Drawing on crisis and psychology research, we find that the exposed individuals show greater grief, psycholinguistic, and social expressiveness, providing evidence of a healing response to crisis and thereby positive psychological effects of the counseling recommendations. We discuss the implications of our work in supporting post-crisis rehabilitation and intervention efforts on college campuses.","Title: Social Support, Reciprocity, and Anonymity in Responses to Sexual Abuse Disclosures on Social Media.\nYear: 2018\n\nAbstract: Seeking and providing support is challenging. When people disclose sensitive information, audience responses can substantially impact the discloser's wellbeing. We use mixed methods to understand responses to online sexual abuse-related disclosures on Reddit. We characterize disclosure responses, then investigate relationships between post content, comment content, and anonymity. We illustrate what types of support sought and provided in posts and comments co-occur. We find that posts seeking support receive more comments, and comments from “throwaway” (i.e., anonymous) accounts are more likely on posts also from throwaway accounts. Anonymous commenting enables commenters to share intimate content such as reciprocal disclosures and supportive messages, and commenter anonymity is not associated with aggressive or unsupportive comments. We argue that anonymity is an essential factor in designing social technologies that facilitate support seeking and provision in socially stigmatized contexts, and provide implications for social media site design. CAUTION: This article includes content about sexual abuse.","Title: A Taxonomy of Ethical Tensions in Inferring Mental Health States from Social Media.\nYear: 2019\n\nAbstract: Powered by machine learning techniques, social media provides an unobtrusive lens into individual behaviors, emotions, and psychological states. Recent research has successfully employed social media data to predict mental health states of individuals, ranging from the presence and severity of mental disorders like depression to the risk of suicide. These algorithmic inferences hold great potential in supporting early detection and treatment of mental disorders and in the design of interventions. At the same time, the outcomes of this research can pose great risks to individuals, such as issues of incorrect, opaque algorithmic predictions, involvement of bad or unaccountable actors, and potential biases from intentional or inadvertent misuse of insights. Amplifying these tensions, there are also divergent and sometimes inconsistent methodological gaps and under-explored ethics and privacy dimensions. This paper presents a taxonomy of these concerns and ethical challenges, drawing from existing literature, and poses questions to be resolved as this research gains traction. We identify three areas of tension: ethics committees and the gap of social media research; questions of validity, data, and machine learning; and implications of this research for key stakeholders. We conclude with calls to action to begin resolving these interdisciplinary dilemmas.","Title: What (or Who) Is Public?: Privacy Settings and Social Media Content Sharing.\nYear: 2017\n\nAbstract: When social networking sites give users granular control over their privacy settings, the result is that some content across the site is public and some is not. How might this content--or characteristics of users who post publicly versus to a limited audience--be different? If these differences exist, research studies of public content could potentially be introducing systematic bias. Via Mechanical Turk, we asked 1,815 Facebook users to share recent posts. Using qualitative coding and quantitative measures, we characterize and categorize the nature of the content. Using machine learning techniques, we analyze patterns of choices for privacy settings. Contrary to expectations, we find that content type is not a significant predictor of privacy setting; however, some demographics such as gender and age are predictive. Additionally, with consent of participants, we provide a dataset of nearly 9,000 public and non-public Facebook posts.","Title: Integrating Artificial and Human Intelligence in Complex, Sensitive Problem Domains: Experiences from Mental Health\nYear: 2018\n\nAbstract: This article presents a position highlighting the importance of combining artificial intelligence approaches with human intelligence, in other words, the involvement of humans. To do so, we specifically focus on problems of societal significance, stemming from complex, sensitive domains. We first discuss our prior work across a series of projects surrounding social media and mental health, and identify major themes for which augmentation of AI systems and techniques with human feedback has been and can be fruitful and meaningful. We then conclude by noting the implications, in terms of opportunities as well as challenges, that can be drawn from our position, both relating to the specific domain of mental health and for AI researchers and practitioners.","Title: Discovering Alternative Treatments for Opioid Use Recovery Using Social Media.\nYear: 2019\n\nAbstract: Opioid use disorder (OUD) poses substantial risks to personal well-being and public health. In online communities, users support those seeking recovery, in part by promoting clinically grounded treatments. However, some communities also promote clinically unverified OUD treatments, such as unregulated and untested drugs. Little research exists on which alternative treatments people use, whether these treatments are effective for recovery, or if they cause negative side effects. We provide the first large-scale social media study of clinically unverified, alternative treatments in OUD recovery on Reddit, partnering with an addiction research scientist. We adopt transfer learning across 63 subreddits to precisely identify posts related to opioid recovery. Then, we quantitatively discover potential alternative treatments and contextualize their effectiveness. Our work benefits health research and practice by identifying undiscovered recovery strategies. We also discuss the impacts to online communities dealing with stigmatized behavior and research ethics.","Title: Methodological Gaps in Predicting Mental Health States from Social Media - Triangulating Diagnostic Signals.\nYear: 2019\n\nAbstract: A growing body of research is combining social media data with machine learning to predict mental health states of individuals. An implication of this research lies in informing evidence-based diagnosis and treatment. However, obtaining clinically valid diagnostic information from sensitive patient populations is challenging. Consequently, researchers have operationalized characteristic online behaviors as \"proxy diagnostic signals\" for building these models. This paper posits a challenge in using these diagnostic signals, purported to support clinical decision-making. Focusing on three commonly used proxy diagnostic signals derived from social media, we find that predictive models built on these data, although offer strong internal validity, suffer from poor external validity when tested on mental health patients. A deeper dive reveals issues of population and sampling bias, as well as of uncertainty in construct validity inherent in these proxies. We discuss the methodological and clinical implications of these gaps and provide remedial guidelines for future research.","Title: Characterizing Homelessness Discourse on Social Media.\nYear: 2019\n\nAbstract: Social media allows us to connect and maintain relationships in spite of physical distance and barriers; as computers and the internet become more accessible, hard-to-reach populations are finding a voice on these platforms. One such group is those who are or have been homeless. Through a computational linguistic analysis of a large corpus of Tumblr blog posts, this paper provides preliminary insights to understand the unique ways homeless bloggers express their needs, frustrations and financial/social distress, connect with others, and seek emotional and practical support from others. We highlight future investigations, building upon this research, that can be pursued in HCI to assist an underserved population with the difficult life experience of homelessness.","Title: Where is the Human? - Bridging the Gap Between AI and HCI.\nYear: 2019\n\nAbstract: In recent years, AI systems have become both more powerful and increasingly promising for integration in a variety of application areas. Attention has also been called to the social challenges these systems bring, particularly in how they might fail or even actively disadvantage marginalised social groups, or how their opacity might make them difficult to oversee and challenge. In the context of these and other challenges, the roles of humans working in tandem with these systems will be important, yet the HCI community has been only a quiet voice in these debates to date. This workshop aims to catalyse and crystallise an agenda around HCI's engagement with AI systems. Topics of interest include explainable and explorable AI; documentation and review; integrating artificial and human intelligence; collaborative decision making; AI/ML in HCI Design; diverse human roles and relationships in AI systems; and critical views of AI.","Title: The Tesserae Project - Large-Scale, Longitudinal, In Situ, Multimodal Sensing of Information Workers.\nYear: 2019\n\nAbstract: The Tesserae project investigates how a suite of sensors can measure workplace performance (e.g., organizational citizenship behavior), psychological traits (e.g., personality, affect), and physical characteristics (e.g., sleep, activity) over one year. We enrolled 757 information workers across the U.S. and measure heart rate, physical activity, sleep, social context, and other aspects through smartwatches, a phone agent, beacons, and social media. We report challenges that we faced with enrollment, privacy, and incentive structures while setting up such a long-term multimodal large-scale sensor study. We discuss the tradeoffs of remote versus in-person enrollment, and showed that directly paid, in-person enrolled participants are more compliant overall compared to remotely-enrolled participants. We find that providing detailed information regarding privacy concerns up-front is highly beneficial. We believe that our experiences can benefit other large sensor projects as this field grows.","Title: Social Media as a Passive Sensor in Longitudinal Studies of Human Behavior and Wellbeing.\nYear: 2019\n\nAbstract: Social media serves as a platform to share thoughts and connect with others. The ubiquitous use of social media also enables researchers to study human behavior as the data can be collected in an inexpensive and unobtrusive way. Not only does social media provide a passive means to collect historical data at scale, it also functions as a \"verbal\" sensor, providing rich signals about an individual's social ecological context. This case study introduces an infrastructural framework to illustrate the feasibility of passively collecting social media data at scale in the context of an ongoing multimodal sensing study of workplace performance (N=757). We study our dataset in its relationship with demographic, personality, and wellbeing attributes of individuals. Importantly, as a means to study selection bias, we examine what characterizes individuals who choose to consent to social media data sharing vs. those who do not. Our work provides practical experiences and implications for research in the HCI field who seek to conduct similar longitudinal studies that harness the potential of social media data.","Title: Designing Dashboard for Campus Stakeholders to Support College Student Mental Health\nYear: 2019\n\nAbstract: Stakeholders, such as college campus administrators and clinicians, are committed to alleviating students' mental health concerns and the campus' mental health climate, but they suffer from a lack of timely and actionable information. Research has revealed that student personal data, such as self-tracking and social media data, can provide in-situ insights about students' mental health states. However, how they can support stakeholders' goals remains unexplored. We examine the potential of user-centered technology in addressing this challenge. We interview campus administrators and clinicians to understand their needs and current practices. Then through a paper prototype, we gather design suggestions for stakeholder-facing dashboards. We discuss three design implications revealed through our studies: that social media can be a potentially useful resource for understanding student mental health despite concerns of data reliability and interpretability; that the dashboards need to assuage stakeholders' concerns around bias and intelligibility of the visual presentations, which can become barriers to future adoption; and that ethical considerations, particularly securing privacy of student data, need to be salient in the design.","Title: A Social Media Study on the Effects of Psychiatric Medication Use.\nYear: 2019\n\nAbstract: Understanding the effects of psychiatric medications during mental health treatment constitutes an active area of inquiry. While clinical trials help evaluate the effects of these medications, many trials suffer from a lack of generalizability to broader populations. We leverage social media data to examine psychopathological effects subject to self-reported usage of psychiatric medication. Using a list of common approved and regulated psychiatric drugs and a Twitter dataset of 300M posts from 30K individuals, we develop machine learning models to first assess effects relating to mood, cognition, depression, anxiety, psychosis, and suicidal ideation. Then, based on a stratified propensity score based causal analysis, we observe that use of specific drugs are associated with characteristic changes in an individual's psychopathology. We situate these observations in the psychiatry literature, with a deeper analysis of pre-treatment cues that predict treatment outcomes. Our work bears potential to inspire novel clinical investigations and to build tools for digital therapeutics.","Title: Differentiating Higher and Lower Job Performers in the Workplace Using Mobile Sensing\nYear: 2019\n\nAbstract: Assessing performance in the workplace typically relies on subjective evaluations, such as, peer ratings, supervisor ratings and self assessments, which are manual, burdensome and potentially biased. We use objective mobile sensing data from phones, wearables and beacons to study workplace performance and offer new insights into behavioral patterns that distinguish higher and lower performers when considering roles in companies (i.e., supervisors and non-supervisors) and different types of companies (i.e., high tech and consultancy). We present initial results from an ongoing year-long study of N=554 information workers collected over a period ranging from 2-8.5 months. We train a gradient boosting classifier that can classify workers as higher or lower performers with AUROC of 0.83. Our work opens the way to new forms of passive objective assessment and feedback to workers to potentially provide week by week or quarter by quarter guidance in the workplace.","Title: Prevalence and Psychological Effects of Hateful Speech in Online College Communities.\nYear: 2019\n\nAbstract: Background. Hateful speech bears negative repercussions and is particularly damaging in college communities. The efforts to regulate hateful speech on college campuses pose vexing socio-political problems, and the interventions to mitigate the effects require evaluating the pervasiveness of the phenomenon on campuses as well the impacts on students' psychological state. \n\nData and Methods. Given the growing use of social media among college students, we target the above issues by studying the online aspect of hateful speech in a dataset of 6 million Reddit comments shared in 174 college communities. To quantify the prevelence of hateful speech in an online college community, we devise College Hate Index (CHX). Next, we examine its distribution across the categories of hateful speech,behavior, class, disability, ethnicity, gender, physical appearance, race, religion, andsexual orientation. We then employ a causal-inference framework to study the psychological effects of hateful speech, particularly in the form of individuals' online stress expression. Finally, we characterize their psychological endurance to hateful speech by analyzing their language -- their discriminatory keyword use, and their personality traits. \n\nResults. We find that hateful speech is prevalent in college subreddits, and 25% of them show greater hateful speech than non-college subreddits. We also find that the exposure to hate leads to greater stress expression. However, everybody exposed is not equally affected; some show lower psychological endurance than others. Low endurance individuals are more vulnerable to emotional outbursts, and are more neurotic than those with higher endurance. \n\n Discussion. Our work bears implications for policy-making and intervention efforts to tackle the damaging effects of online hateful speech in colleges. From technological perspective, our work caters to mental health support provisions on college campuses, and to moderation efforts in online college communities. In addition, given the charged aspect of speech dilemma, we highlight the ethical implications of our work. Our work lays the foundation for studying the psychological impacts of hateful speech in online communities in general, and situated communities in particular (the ones that have both an offline and an online analog).","Title: Introduction to this special issue on unifying human computer interaction and artificial intelligence\nYear: 2020\n\nAbstract: McCarthy (1998) defined Artificial Intelligence (AI) as both “the science and engineering of intelligent machines, especially computer programs” and the “computational part of the ability to achieve goals in the world.” Today, AI is increasingly deployed across many domains of direct societal relevance, such as transportation, retail, criminal justice, finance, and health. But these very domains that AI is aiming to revolutionize may also be where human implications are the most momentous. The potential negative effects of AI on society, whether amplifying human biases or the perils of automation, cannot be ignored, and as a result, such topics are increasingly discussed in scholarly and popular press contexts. As the New York Times notes:“… if we want [AI] to play a positive role in tomorrow’s world, it must be guided by human concerns”(Li, 2018). The relationship between technology and humans is the direct focus of …","Title: Social media derived biomarkers of mental health: opportunities, pitfalls, and the next frontier\nYear: 2021\n\nAbstract: ABSTRACTSocial media data is being increasingly used to computationally learn about and infer behaviors and underlying psychologies of people. Adopting a social ecological perspective, this talk highlights a series of approaches that allow the gleaning of potentially useful mental health biomarkers by harnessing At the same time, the talk discusses a critical analytic study surrounding the pitfalls of social media biomarkers of mental health -- in particular, the theoretical, domain, and psychometric validity of this novel information source as well as its underlying biases, when appropriated to augment conventionally gathered biomarkers, such as those gathered via surveys and verbal self-reports. Then, to overcome these pitfalls, this talk presents results from a case study, where computational algorithms to glean mental health biomarkers from social media were developed in a context-sensitive and human-centered way, in collaboration with domain experts and stakeholders. Specifically, this study, a collaboration with a health provider, reveals the ability and implications of using social media data of consented schizophrenia patients to forecast relapse and support clinical decision-making. The talk concludes with provocations of the path forward, emphasizing the need for a collaborative, multidisciplinary research agenda while realizing the potential of social media derived biomarkers in mental health -- one that incorporates methodological rigor, ethics, and accountability, all at once.","Title: Latent Hatred - A Benchmark for Understanding Implicit Hate Speech.\nYear: 2021\n\nAbstract: Hate speech has grown significantly on social media, causing serious consequences for victims of all demographics. Despite much attention being paid to characterize and detect discriminatory speech, most work has focused on explicit or overt hate speech, failing to address a more pervasive form based on coded or indirect language. To fill this gap, this work introduces a theoretically-justified taxonomy of implicit hate speech and a benchmark corpus with fine-grained labels for each message and its implication. We present systematic analyses of our dataset using contemporary baselines to detect and explain implicit hate speech, and we discuss key features that challenge existing models. This dataset will continue to serve as a useful benchmark for understanding this multifaceted issue.","Title: MOSafely: Building an Open-Source HCAI Community to Make the Internet a Safer Place for Youth\nYear: 2021\n\nAbstract: ABSTRACTThe goal of this one-day workshop is to build an active community of researchers, practitioners, and policy-makers who are jointly committed to leveraging human-centered artificial intelligence (HCAI) to make the internet a safer place for youth. This community will be founded on the principles of open innovation and human dignity to address some of the most salient safety issues of modern-day internet, including online harassment, sexual solicitation, and the mental health of vulnerable internet users, particularly adolescents and young adults. We will partner with Mozilla Research Foundation to launch a new open project named “MOSafely.org,” which will serve as a platform for code library, research, and data contributions that support the mission of internet safety. During the workshop, we will discuss: 1) the types of contributions and technical standards needed to advance the state-of-the art in online risk detection, 2) the practical, legal, and ethical challenges that we will face, and 3) ways in which we can overcome these challenges through the use of HCAI to create a sustainable community. An end goal of creating the MOSafely community is to offer evidence-based, customizable, robust, and low-cost technologies that are accessible to the public for youth protection.","Title: Assessing the mental health of college students by leveraging social media data\nYear: 2021\n\nAbstract: AbstractThe mental health of college students is a growing concern and gauging the mental health needs of this group is difficult to assess in real-time and in scale. The ubiquity and widespread use of social media, particularly among young adults, provides opportunities for various stakeholders to proactively assess the mental health of college students and provide timely and tailored support.","Title: Overcoming Language Disparity in Online Content Classification with Multimodal Learning\nYear: 2022\n\nAbstract: Advances in Natural Language Processing (NLP) have revolutionized the way researchers and practitioners address crucial societal problems. Large language models are now the standard to develop state-of-the-art solutions for text detection and classification tasks. However, the development of advanced computational techniques and resources is disproportionately focused on the English language, sidelining a majority of the languages spoken globally. While existing research has developed better multilingual and monolingual language models to bridge this language disparity between English and non-English languages, we explore the promise of incorporating the information contained in images via multimodal machine learning. Our comparative analyses on three detection tasks focusing on crisis information, fake news, and emotion recognition, as well as five high-resource non-English languages, demonstrate that: (a) detection frameworks based on pre-trained large language models like BERT and multilingual-BERT systematically perform better on the English language compared against non-English languages, and (b) including images via multimodal learning bridges this performance gap. We situate our findings with respect to existing work on the pitfalls of large language models, and discuss their theoretical and practical implications. Resources for this paper are available at https://multimodality-language-disparity.github.io/.","Title: How Is Vaping Framed on Online Knowledge Dissemination Platforms?\nYear: 2022\n\nAbstract: Studying how vaping is framed on various knowledge dissemination platforms (e.g., Quora, Reddit, Wikipedia) is central to understanding the process of knowledge dissemination around vaping. Such understanding can help us craft tools specific to each platform, to dispel vaping misperceptions and reinforce evidence-based information. We analyze 1,888 articles and 1,119,453 vaping posts to study how vaping is framed across multiple knowledge dissemination platforms (Wikipedia, Quora, Medium, Reddit, Stack Exchange, wikiHow). We use NLP techniques to understand these differences. As an example, regarding question answering results, for the question What is vaping for?, we note answers framing vaping as a smoking cessation tool in Quora, Medium, and Stack Exchange. Reddit tended to frame vaping as a hobby. Wikipedia had a mix of answers, some centered on EVALI, and others on vaping as harm reduction. Broadly, results indicate that Quora is an appropriate venue for those looking to transition from smoking to vaping. Other platforms (Reddit, wikiHow) are more for vaping hobbyists and may not sufficiently dissuade youth vaping. Conversely, Wikipedia may exaggerate vaping harms, dissuading smokers from transitioning. A strength of our work is how the different techniques we have applied validate each other. Stakeholders may utilize our findings to design vaping regulation that clarifies the role of vapes as a smoking cessation tool.","Title: Employing Social Media to Improve Mental Health: Pitfalls, Lessons Learned, and the Next Frontier\nYear: 2022\n\nAbstract: ABSTRACT Social media data is being increasingly used to computationally learn about and infer the mental health states of individuals and populations. Despite being touted as a powerful means to shape interventions and impact mental health recovery, little do we understand about the theoretical, domain, and psychometric validity of this novel information source, or its underlying biases, when appropriated to augment conventionally gathered data, such as surveys and verbal self-reports. This talk presents a critical analytic perspective on the pitfalls of social media signals of mental health, especially when they are derived from “proxy” diagnostic indicators, often removed from the real-world context in which they are likely to be used. Then, to overcome these pitfalls, this talk presents results from two case studies, where machine learning algorithms to glean mental health insights from social media were developed in a context-sensitive and human-centered way, in collaboration with domain experts and stakeholders. The first of these case studies, a collaboration with a health provider, focuses on the individual-perspective, and reveals the ability and implications of using social media data of consented schizophrenia patients to forecast relapse and support clinical decision-making. Scaling up to populations, in collaboration with a federal organization and towards influencing public health policy, the second case study seeks to forecast nationwide rates of suicide fatalities using social media signals, in conjunction with health services data. The talk concludes with discussions of the path forward, emphasizing the need for a collaborative, multi-disciplinary research agenda while realizing the potential of social media data and machine learning in mental health – one that incorporates methodological rigor, ethics, and accountability, all at once."],"string":"[\n \"Title: Discovering multirelational structure in social media streams\\nYear: 2012\\n\\nAbstract: In this article, we present a novel algorithm to discover multirelational structures from social media streams. A media item such as a photograph exists as part of a meaningful interrelationship among several attributes, including time, visual content, users, and actions. Discovery of such relational structures enables us to understand the semantics of human activity and has applications in content organization, recommendation algorithms, and exploratory social network analysis. We are proposing a novel nonnegative matrix factorization framework to characterize relational structures of group photo streams. The factorization incorporates image content features and contextual information. The idea is to consider a cluster as having similar relational patterns; each cluster consists of photos relating to similar content or context. Relations represent different aspects of the photo stream data, including visual content, associated tags, photo owners, and post times. The extracted structures minimize the mutual information of the predicted joint distribution. We also introduce a relational modularity function to determine the structure cost penalty, and hence determine the number of clusters. Extensive experiments on a large Flickr dataset suggest that our approach is able to extract meaningful relational patterns from group photo streams. We evaluate the utility of the discovered structures through a tag prediction task and through a user study. Our results show that our method based on relational structures, outperforms baseline methods, including feature and tag frequency based techniques, by 35%--420%. We have conducted a qualitative user study to evaluate the benefits of our framework in exploring group photo streams. The study indicates that users found the extracted clustering results clearly represent major themes in a group; the clustering results not only reflect how users describe the group data but often lead the users to discover the evolution of the group activity.\",\n \"Title: \\\"Moon Phrases\\\": a social media faciliated tool for emotional reflection and wellness\\nYear: 2013\\n\\nAbstract: We propose an early prototype: a web-based tool \\\"Moon Phrases\\\" that leverages an individual's social activity online for promoting emotional reflection and wellness. Specifically, Moon Phrases tracks the emotion and linguistic expression of individuals as manifested on the social media Twitter, and presents a novel visualization---an analogy to the phases of the moon, to reveal their longitudinal trends. Social media platforms, including Twitter and Facebook provide a window onto the thoughts and feelings of individuals around small and big happenings in their lives. Motivated from research in psychology and HCI, we hypothesize that identifying the changes in language, emotion, and social activity on social media would enable individuals to reflect on their own behavior over time and in a fine-grained manner, which are otherwise known to be difficult to keep track of. We believe Moon Phrases thus bears the potential to act as a self-narrative or \\\"behavioral fingerprint\\\", and thereby serve as an unobtrusive mechanism to facilitate emotional wellness in individuals.\",\n \"Title: Inferring relevant social networks from interpersonal communication\\nYear: 2010\\n\\nAbstract: Researchers increasingly use electronic communication data to construct and study large social networks, effectively inferring unobserved ties (e.g. i is connected to j) from observed communication events (e.g. i emails j). Often overlooked, however, is the impact of tie definition on the corresponding network, and in turn the relevance of the inferred network to the research question of interest. Here we study the problem of network inference and relevance for two email data sets of different size and origin. In each case, we generate a family of networks parameterized by a threshold condition on the frequency of emails exchanged between pairs of individuals. After demonstrating that different choices of the threshold correspond to dramatically different network structures, we then formulate the relevance of these networks in terms of a series of prediction tasks that depend on various network features. In general, we find: a) that prediction accuracy is maximized over a non-trivial range of thresholds corresponding to 5-10 reciprocated emails per year; b) that for any prediction task, choosing the optimal value of the threshold yields a sizable (~30%) boost in accuracy over naive choices; and c) that the optimal threshold value appears to be (somewhat surprisingly) consistent across data sets and prediction tasks. We emphasize the practical utility in defining ties via their relevance to the prediction task(s) at hand and discuss implications of our empirical results.\",\n \"Title: CONNECTING CONTENT TO COMMUNITY IN SOCIAL MEDIA VIA IMAGE CONTENT, USER TAGS AND USER COMMUNICATION\\nYear: 2009\\n\\nAbstract: In this paper we develop a recommendation framework to connect image content with communities in online social media. The problem is important because users are looking for useful feedback on their uploaded content, but finding the right community for feedback is challenging for the end user. Social media are characterized by both content and community. Hence, in our approach, we characterize images through three types of features: visual features, user generated text tags, and social interaction (user communication history in the form of comments). A recommendation framework based on learning a latent space representation of the groups is developed to recommend the most likely groups for a given image. The model was tested on a large corpus of Flickr images comprising 15,689 images. Our method outperforms the baseline method, with a mean precision 0.62 and mean recall 0.69. Importantly, we show that fusing image content, text tags with social interaction features outperforms the case of only using image content or tags.\",\n \"Title: \\\"Narco\\\" emotions: affect and desensitization in social media during the mexican drug war\\nYear: 2014\\n\\nAbstract: Social media platforms have emerged as prominent information sharing ecosystems in the context of a variety of recent crises, ranging from mass emergencies, to wars and political conflicts. We study affective responses in social media and how they might indicate desensitization to violence experienced in communities embroiled in an armed conflict. Specifically, we examine three established affect measures: negative affect, activation, and dominance as observed on Twitter in relation to a number of statistics on protracted violence in four major cities afflicted by the Mexican Drug War. During a two year period (Aug 2010 - Dec 2012), while violence was on the rise in these regions, our findings show a decline in negative emotional expression as well as a rise in emotional arousal and dominance in Twitter posts: aspects known to be psychological markers of desensitization. We discuss the implications of our work for behavioral health, facilitating rehabilitation efforts in communities enmeshed in an acute and persistent urban warfare, and the impact on civic engagement.\",\n \"Title: \\\"Understanding our online communication processes\\\" by Munmun De Choudhury with Danielle H. Lee as coordinator\\nYear: 2012\\n\\nAbstract: This article presents an overview of the dissertation work entitled \\\"Analyzing the Dynamics of Communication in Online Social Networks\\\", by Munmun De Choudhury. It was completed in 2011 at the Arizona State University, Tempe, under the supervision of Prof. Hari Sundaram. The dissertation deals with the analysis of interpersonal communication dynamics in online social networks and social media. Communication dynamics have been of interest to researchers from multi-faceted domains over the past several decades. However, today we are faced with several modern capabilities encompassing a host of social media websites. This research is geared towards developing methods, tools and frameworks towards understanding and addressing the associated challenges of making sense of the modern online communication processes. We believe that this research can make significant contribution into a better understanding of how we communicate online and how it is redefining our collective sociological behavior.\",\n \"Title: Identifying relevant social media content: leveraging information diversity and user cognition\\nYear: 2011\\n\\nAbstract: As users turn to large scale social media systems like Twitter for topic-based content exploration, they quickly face the issue that there may be hundreds of thousands of items matching any given topic they might query. Given the scale of the potential result sets, how does one identify the 'best' or 'right' set of items? We explore a solution that aligns characteristics of the information space, including specific content attributes and the information diversity of the results set, with measurements of human information processing, including engagement and recognition memory. Using Twitter as a test bed, we propose a greedy iterative clustering technique for selecting a set of items on a given topic that matches a specified level of diversity. In a user study, we show that our proposed method yields sets of items that were, on balance, more engaging, better remembered, and rated as more interesting and informative compared to baseline techniques. Additionally, diversity indeed seemed to be important to participants in the study in the consumption of content. However as a rather surprising result, we also observe that content was perceived to be more relevant when it was highly homogeneous or highly heterogeneous. In this light, implications for the selection and evaluation of topic-centric item sets in social media contexts are discussed.\",\n \"Title: Discovery of information disseminators and receptors on online social media\\nYear: 2010\\n\\nAbstract: Today, there is significant sharing of information artifacts among users on various social media sites, including Digg, Twitter and Flickr. An interesting consequence of such rich and extensive social interaction is the evolving nature of \\\"roles\\\" that are acquired by users over time, in the context of variegated communication activities, such as commenting, replying, uploading a media artifact and so on. In this paper, we investigate the discovery of two roles that define information dissipation: disseminators and receptors. We propose a computational framework based on factorization of stacked representation of activities and test the outcomes on a dataset from Digg. Experiments show that our approach can, interestingly, reveal correlations with user activities occurring at a future point in time.\",\n \"Title: Characterizing and predicting postpartum depression from shared facebook data\\nYear: 2014\\n\\nAbstract: The birth of a child is a major milestone in the life of parents. We leverage Facebook data shared voluntarily by 165 new mothers as streams of evidence for characterizing their postnatal experiences. We consider multiple measures including activity, social capital, emotion, and linguistic style in participants' Facebook data in pre- and postnatal periods. Our study includes detecting and predicting onset of post-partum depression (PPD). The work complements recent work on detecting and predicting significant postpartum changes in behavior, language, and affect from Twitter data. In contrast to prior studies, we gain access to ground truth on postpartum experiences via self-reports and a common psychometric instrument used to evaluate PPD. We develop a series of statistical models to predict, from data available before childbirth, a mother's likelihood of PPD. We corroborate our quantitative findings through interviews with mothers experiencing PPD. We find that increased social isolation and lowered availability of social capital on Facebook, are the best predictors of PPD in mothers.\",\n \"Title: Finding and assessing social media information sources in the context of journalism\\nYear: 2012\\n\\nAbstract: Social media is already a fixture for reporting for many journalists, especially around breaking news events where non-professionals may already be on the scene to share an eyewitness report, photo, or video of the event. At the same time, the huge amount of content posted in conjunction with such events serves as a challenge to finding interesting and trustworthy sources in the din of the stream. In this paper we develop and investigate new methods for filtering and assessing the verity of sources found through social media by journalists. We take a human centered design approach to developing a system, SRSR (\\\"Seriously Rapid Source Review\\\"), informed by journalistic practices and knowledge of information production in events. We then used the system, together with a realistic reporting scenario, to evaluate the filtering and visual cue features that we developed. Our evaluation offers insights into social media information sourcing practices and challenges, and highlights the role technology can play in the solution.\",\n \"Title: Dynamic prediction of communication flow using social context\\nYear: 2008\\n\\nAbstract: In this paper, we develop a temporally evolving representation framework for context that can efficiently predict communication flow in social networks between a given pair of individuals. The problem is important because it facilitates determining social and market trends as well as efficient information paths among people. We describe communication flow by two parameters: the intent to communicate and communication delay. To estimate these parameters, we design features to characterize communication and social context. Communication context refers to the attributes of current communication. Social context refers to the patterns of participation in communication (information roles) and the degree of overlap of friends between two people (strength of ties). A subset of optimal features of the communication and social context is chosen at a given time instant using five different feature selection strategies. The features are thereafter used in a Support Vector Regression framework to predict the intent to communicate and the delay between a pair of individuals. We have excellent results on a real world dataset from the most popular social networking site, www.myspace.com. We observe interestingly that while context can reasonably predict intent, delay seems to be more dependent on the personal contextual changes and other latent factors characterizing communication, e.g. 'age' of information transmitted and presence of cliques among people.\",\n \"Title: Major life changes and behavioral markers in social media: case of childbirth\\nYear: 2013\\n\\nAbstract: We explore the harnessing of social media as a window on changes around major life events in individuals and larger populations. We specifically examine patterns of activity, emotional, and linguistic correlates for childbirth and postnatal course. After identifying childbirth events on Twitter, we analyze daily posting patterns and language usage before and after birth by new mothers, and make inferences about the status and dynamics of changes in emotions expressed following childbirth. We find that childbirth is associated with some changes for most new mothers, but approximately 15% of new mothers show significant changes in their online activity and emotional expression postpartum. We observe that these mothers can be distinguished by linguistic changes captured by shifts in a relatively small number of words in their social media posts. We introduce a greedy differencing procedure to identify the type of language that characterizes significant changes in these mothers during postpartum. We conclude with a discussion about how such characterizations might be applied to recognizing and understanding health and well-being in women following childbirth.\",\n \"Title: Constructing travel itineraries from tagged geo-temporal breadcrumbs\\nYear: 2010\\n\\nAbstract: Vacation planning is a frequent laborious task which requires skilled interaction with a multitude of resources. This paper develops an end-to-end approach for constructing intra-city travel itineraries automatically by tapping a latent source reflecting geo-temporal breadcrumbs left by millions of tourists. In particular, the popular rich media sharing site, Flickr, allows photos to be stamped by the date and time of when they were taken, and be mapped to Points Of Interest (POIs) by latitude-longitude information as well as semantic metadata (e.g., tags) that describe them. Our extensive user study on a \\\"crowd-sourcing\\\" marketplace (Amazon Mechanical Turk), indicates that high quality itineraries can be automatically constructed from Flickr data, when compared against popular professionally generated bus tours.\",\n \"Title: Multi-scale characterization of social network dynamics in the blogosphere\\nYear: 2008\\n\\nAbstract: We have developed a computational framework to characterize social network dynamics in the blogosphere at individual, group and community levels. Such characterization could be used by corporations to help drive targeted advertising and to track the moods and sentiments of consumers. We tested our model on a widely read technology blog called Engadget. Our results show that communities transit between states of high and low entropy, depending on sentiments (positive / negative) about external happenings. We also propose an innovative method to establish the utility of the extracted knowledge, by correlating the mined knowledge with an external time series data (the stock market). Our validation results show that the characterized groups exhibit high stock market movement predictability (89%) and removal of 'impactful' groups makes the community less resilient by lowering predictability (26%) and affecting the composition of the groups in the rest of the community.\",\n \"Title: How Does the Data Sampling Strategy Impact the Discovery of Information Diffusion in Social Media?\\nYear: 2010\\n\\nAbstract: Platforms such as Twitter have provided researchers with ample opportunities to analytically study social phenomena. There are however, significant computational challenges due to the enormous rate of production of new information: re- searchers are therefore, often forced to analyze a judiciously selected \\\"sample\\\" of the data. Like other social media phe- nomena, information diffusion is a social process-it is af- fected by user context, and topic, in addition to the graph topology. This paper studies the impact of different attribute and topology based sampling strategies on the discovery of an important social media phenomena-information diffusion. We examine several widely-adopted sampling methods that select nodes based on attribute (random, location, and activ- ity) and topology (forest fire) as well as study the impact of attribute based seed selection on topology based sampling. Then we develop a series of metrics for evaluating the quality of the sample, based on user activity (e.g. volume, number of seeds), topological (e.g. reach, spread) and temporal char- acteristics (e.g. rate). We additionally correlate the diffusion volume metric with two external variables-search and news trends. Our experiments reveal that for small sample sizes (30%), a sample that incorporates both topology and user- context (e.g. location, activity) can improve on na¨ ive meth- ods by a significant margin of ∼15-20%.\",\n \"Title: Automatic construction of travel itineraries using social breadcrumbs\\nYear: 2010\\n\\nAbstract: Vacation planning is one of the frequent---but nonetheless laborious---tasks that people engage themselves with online; requiring skilled interaction with a multitude of resources. This paper constructs intra-city travel itineraries automatically by tapping a latent source reflecting geo-temporal breadcrumbs left by millions of tourists. For example, the popular rich media sharing site, Flickr, allows photos to be stamped by the time of when they were taken and be mapped to Points Of Interests (POIs) by geographical (i.e. latitude-longitude) and semantic (e.g., tags) metadata. Leveraging this information, we construct itineraries following a two-step approach. Given a city, we first extract photo streams of individual users. Each photo stream provides estimates on where the user was, how long he stayed at each place, and what was the transit time between places. In the second step, we aggregate all user photo streams into a POI graph. Itineraries are then automatically constructed from the graph based on the popularity of the POIs and subject to the user's time and destination constraints. We evaluate our approach by constructing itineraries for several major cities and comparing them, through a \\\"crowd-sourcing\\\" marketplace (Amazon Mechanical Turk), against itineraries constructed from popular bus tours that are professionally generated. Our extensive survey-based user studies over about 450 workers on AMT indicate that high quality itineraries can be automatically constructed from Flickr data.\",\n \"Title: Computational social science: CSCW in the social media era\\nYear: 2014\\n\\nAbstract: With the widespread proliferation of social media tools such as Facebook and Twitter, the CSCW community has seen a growing interest among researchers to turn to records of social behavior from blogs, social media, and social networking sites, to study human social behavior. This nascent area, that has begun to be referred to in various research circles as \\\\\\\"computational social science\\\\\\\", provides an exciting and promising development in the CSCW community. This panel brings together a host of researchers with varied disciplinary perspectives to investigate the potential and current state-of-the-art, as well as forthcoming challenges, practical and methodological issues that engender this emerging topic.\",\n \"Title: Can social media help us reason about mental health?\\nYear: 2014\\n\\nAbstract: Millions of people each year suffer from depression, which makes mental illness one of the most serious and widespread health challenges in our society today. There is therefore a need for effective policies, interventions, and prevention strategies that enable early detection and diagnosis of mental health concerns in populations. This talk reports some findings on the potential of leveraging social media postings as a new type of lens in understanding mental illness in individuals and populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements of behavior over time while radically expanding population sample sizes. The talk highlights how this research direction may be useful in developing tools for identifying the onset of depressive disorders, for use by healthcare agencies; or on behalf of individuals, enabling those suffering from mental illness to be more proactive about their mental health.\",\n \"Title: \\\"Birds of a Feather\\\": Does User Homophily Impact Information Diffusion in Social Media?\\nYear: 2010\\n\\nAbstract: This article investigates the impact of user homophily on the social process\\nof information diffusion in online social media. Over several decades, social\\nscientists have been interested in the idea that similarity breeds connection:\\nprecisely known as \\\"homophily\\\". Homophily has been extensively studied in the\\nsocial sciences and refers to the idea that users in a social system tend to\\nbond more with ones who are similar to them than to ones who are dissimilar.\\nThe key observation is that homophily structures the ego-networks of\\nindividuals and impacts their communication behavior. It is therefore likely to\\neffect the mechanisms in which information propagates among them. To this\\neffect, we investigate the interplay between homophily along diverse user\\nattributes and the information diffusion process on social media. In our\\napproach, we first extract diffusion characteristics---corresponding to the\\nbaseline social graph as well as graphs filtered on different user attributes\\n(e.g. location, activity). Second, we propose a Dynamic Bayesian Network based\\nframework to predict diffusion characteristics at a future time. Third, the\\nimpact of attribute homophily is quantified by the ability of the predicted\\ncharacteristics in explaining actual diffusion, and external variables,\\nincluding trends in search and news. Experimental results on a large Twitter\\ndataset demonstrate that choice of the homophilous attribute can impact the\\nprediction of information diffusion, given a specific metric and a topic. In\\nmost cases, attribute homophily is able to explain the actual diffusion and\\nexternal trends by ~15-25% over cases when homophily is not considered.\",\n \"Title: Understanding affect in the workplace via social media\\nYear: 2013\\n\\nAbstract: We investigate the landscape of affective expression of employees at a large Fortune 500 software corporation via an internal microblogging tool. We present three analyses of emotional expression among employees, based on literature in organizational behavior: its relationship to (1) exogenous/lifestyle and endogenous workplace factors, (2) geography and (3) organizational structure. We find that employees tend to make significant accommodations in affect expression when interacting with others over the organizational hierarchy. We also find that positive affect is expressed through interpersonal communications that connect disparate geographic regions. Our findings have implications for enabling emotional reflection of employees and for management in that they can help uncover emotional patterns associated with episodes of high and low productivity, allowing organizations to improve employee engagement and promote positive attitudes.\",\n \"Title: Tie Formation on Twitter: Homophily and Structure of Egocentric Networks\\nYear: 2011\\n\\nAbstract: Both homophily and tie formation remain well studied problems in the social sciences literature since several decades. Prior empirical work on networks seems to indicate that in several situations, high degree of homophily was observed to be behind an individual's desire to establish new ties. However in the context of today's social media, not all individuals are the same, topologically. That is, we observe a variety of ego network structures based on individuals' inlink-outlink relationships. In the context of tie formation in these networks, do different ego network topologies exhibit homophily along different attributes? How can we quantify and investigate these differences? To this end, we propose a variety of attributes along which homophily can be measured between individuals: including demographic attributes, activity-specific attributes and content-based attributes. We further categorize ego network structures as generators, mediators and receptors based on a measure called ego ratio. In our experiments on a large Twitter dataset comprising about 29.5M tweets, we observe, somewhat surprisingly, that for a few attributes, there was consistently high homophily (topical interest)/low homophily (gender, ethnicity) regardless of the ego network structure. Otherwise, mediators were observed to associate tie formation extensively with location, interactive ness and sentiment homophily, whereas generators were driven largely by information broadcasting behavior homophily. Implications of the findings in understanding the diverse range of motivations behind user participation in social media sites are discussed.\",\n \"Title: Multimedia Semantics: Interactions Between Content and Community.\\nYear: 2012\\n\\nAbstract: This paper reviews the state of the art and some emerging issues in research areas related to pattern analysis and monitoring of web-based social communities. This research area is important for several reasons. First, the presence of near-ubiquitous low-cost computing and communication technologies has enabled people to access and share information at an unprecedented scale. The scale of the data...\",\n \"Title: What makes conversations interesting?: themes, participants and consequences of conversations in online social media\\nYear: 2009\\n\\nAbstract: Rich media social networks promote not only creation and consumption of media, but also communication about the posted media item. What causes a conversation to be interesting, that prompts a user to participate in the discussion on a posted video? We conjecture that people participate in conversations when they find the conversation theme interesting, see comments by people whom they are familiar with, or observe an engaging dialogue between two or more people (absorbing back and forth exchange of comments). Importantly, a conversation that is interesting must be consequential - i.e. it must impact the social network itself. Our framework has three parts: characterizing themes, characterizing participants for determining interestingness and measures of consequences of a conversation deemed to be interesting. First, we detect conversational themes using a mixture model approach. Second, we determine interestingness of participants and interestingness of conversations based on a random walk model. Third, we measure the consequence of a conversation by measuring how interestingness affects the following three variables - participation in related themes, participant cohesiveness and theme diffusion. We have conducted extensive experiments using dataset from the popular video sharing site, YouTube. Our results show that our method of interestingness maximizes the mutual information, and is significantly better (twice as large) than three other baseline methods (number of comments, number of new participants and PageRank based assessment).\",\n \"Title: Predicting postpartum changes in emotion and behavior via social media\\nYear: 2013\\n\\nAbstract: We consider social media as a promising tool for public health, focusing on the use of Twitter posts to build predictive models about the forthcoming influence of childbirth on the behavior and mood of new mothers. Using Twitter posts, we quantify postpartum changes in 376 mothers along dimensions of social engagement, emotion, social network, and linguistic style. We then construct statistical models from a training set of observations of these measures before and after the reported childbirth, to forecast significant postpartum changes in mothers. The predictive models can classify mothers who will change significantly following childbirth with an accuracy of 71%, using observations about their prenatal behavior, and as accurately as 80-83% when additionally leveraging the initial 2-3 weeks of postnatal data. The study is motivated by the opportunity to use social media to identify mothers at risk of postpartum depression, an underreported health concern among large populations, and to inform the design of low-cost, privacy-sensitive early-warning systems and intervention programs aimed at promoting wellness postpartum.\",\n \"Title: Social media as a measurement tool of depression in populations\\nYear: 2013\\n\\nAbstract: Depression is a serious and widespread public health challenge. We examine the potential for leveraging social media postings as a new type of lens in understanding depression in populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements over time while radically expanding population sample sizes. We present work on using a crowdsourcing methodology to build a large corpus of postings on Twitter that have been shared by individuals diagnosed with clinical depression. Next, we develop a probabilistic model trained on this corpus to determine if posts could indicate depression. The model leverages signals of social activity, emotion, and language manifested on Twitter. Using the model, we introduce a social media depression index that may serve to characterize levels of depression in populations. Geographical, demographic and seasonal patterns of depression given by the measure confirm psychiatric findings and correlate highly with depression statistics reported by the Centers for Disease Control and Prevention (CDC).\",\n \"Title: Understanding Community Dynamics in Online Social Networks: A multidisciplinary review.\\nYear: 2012\\n\\nAbstract: Social network systems are significant scaffolds for political, economic, and sociocultural change. This is in part due to the widespread availability of sophisticated network technologies and the concurrent emergence of rich media Web sites. Social network sites provide new opportunities for social-technological research. Since we can inexpensively collect electronic records (over extended period...\",\n \"Title: Social Synchrony: Predicting Mimicry of User Actions in Online Social Media\\nYear: 2009\\n\\nAbstract: We propose a computational framework to predict synchronyof action in online social media. Synchrony is a temporalsocial network phenomenon in which a large number of usersare observed to mimic a certain action over a period of timewith sustained participation from early users.Understanding social synchrony can be helpful in identifyingsuitable time periods of viral marketing. Our method consistsof two parts – the learning framework and the evolutionframework. In the learning framework, we develop a DBNbased representation that includes an understanding of usercontext to predict the probability of user actions over a set oftime slices into the future. In the evolution framework, weevolve the social network and the user models over a set offuture time slices to predict social synchrony. Extensiveexperiments on a large dataset crawled from the popularsocial media site Digg (comprising ~7M diggs) show thatour model yields low error (15.2+4.3%) in predicting useractions during periods with and without synchrony.Comparison with baseline methods indicates that our methodshows significant improvement in predicting user actions.\",\n \"Title: Role of social media in tackling challenges in mental health\\nYear: 2013\\n\\nAbstract: Mental illness is a serious and widespread health challenge in our society today. Tens of millions of people each year suffer from depression and only a fraction receives adequate treatment. This position paper highlights some recent attempts examining the potential for leveraging social media postings as a new type of lens in understanding mental illness in individuals and populations. Information gleaned from social media bears potential to complement traditional survey techniques in its ability to provide finer grained measurements of behavior over time while radically expanding population sample sizes. We conclude highlighting how this research direction may be useful in developing tools for identifying the onset of depressive disorders in individuals, for use by healthcare agencies; or on behalf of individuals, enabling those suffering from mental illness to be more proactive about their mental health.\",\n \"Title: Contextual Prediction of Communication Flow in Social Networks\\nYear: 2007\\n\\nAbstract: The paper develops a novel computational framework for predicting communication flow in social networks based on several contextual features. The problem is important because prediction of communication flow can impact timely sharing of specific information across a wide array of communities. We determine the intent to communicate and communication delay between users based on several contextual features in a social network corresponding to (a) neighborhood context, (b) topic context and (c) recipient context. The intent to communicate and communication delay are modeled as regression problems which are efficiently estimated using Support Vector Regression. We predict the intent and the delay, on an interval of time using past communication data. We have excellent prediction results on a real-world dataset from MySpace.com with an accuracy of 13-16%. We show that the intent to communicate is more significantly influenced by contextual factors compared to the delay.\",\n \"Title: The new war correspondents: the rise of civic media curation in urban warfare\\nYear: 2013\\n\\nAbstract: In this paper we examine the information sharing practices of people living in cities amid armed conflict. We describe the volume and frequency of microblogging activity on Twitter from four cities afflicted by the Mexican Drug War, showing how citizens use social media to alert one another and to comment on the violence that plagues their communities. We then investigate the emergence of civic media \\\\\\\"curators,\\\\\\\" individuals who act as \\\\\\\"war correspondents\\\\\\\" by aggregating and disseminating information to large numbers of people on social media. We conclude by outlining the implications of our observations for the design of civic media systems in wartime.\",\n \"Title: Extraction, characterization and utility of prototypical communication groups in the blogosphere\\nYear: 2010\\n\\nAbstract: This article analyzes communication within a set of individuals to extract the representative prototypical groups and provides a novel framework to establish the utility of such groups. Corporations may want to identify representative groups (which are indicative of the overall communication set) because it is easier to track the prototypical groups rather than the entire set. This can be useful for advertising, identifying “hot” spots of resource consumption as well as in mining representative moods or temperature of a community. Our framework has three parts: extraction, characterization, and utility of prototypical groups. First, we extract groups by developing features representing communication dynamics of the individuals. Second, to characterize the overall communication set, we identify a subset of groups within the community as the prototypical groups. Third, we justify the utility of these prototypical groups by using them as predictors of related external phenomena; specifically, stock market movement of technology companies and political polls of Presidential candidates in the 2008 U.S. elections. We have conducted extensive experiments on two popular blogs, Engadget and Huffington Post. We observe that the prototypical groups can predict stock market movement/political polls satisfactorily with mean error rate of 20.32%. Further, our method outperforms baseline methods based on alternative group extraction and prototypical group identification methods. We evaluate the quality of the extracted groups based on their conductance and coverage measures and develop metrics: predictivity and resilience to evaluate their ability to predict a related external time-series variable (stock market movement/political polls). This implies that communication dynamics of individuals are essential in extracting groups in a community, and the prototypical groups extracted by our method are meaningful in characterizing the overall communication sets.\",\n \"Title: Context Aware Routing of Enterprise User Communications\\nYear: 2007\\n\\nAbstract: This paper develops a context aware framework to address the diverse communication needs of a modern enterprise. Such enterprises are characterized by workers in different locations, subject to different policies, using different communication devices, and having varying degrees of skill sets. This diversity poses challenges in finding the most effective human worker (agent) for tasks like fielding a customer request, helping another agent with additional expert knowledge, or more generally help complete a task like a supply chain exception. We focus on the problem of routing communications to the most effective agent using a spectrum of contextual knowledge: availability, media type, activity, expertise, and location. We determine an optimal \\\"request-to-agent' routing based on several metrics of effectiveness depending on the communication context. The optimal agent is selected to communicate on a specific media who minimizes the expected duration of interaction while maximizes the probability of successful call completion. Based on our model we have conducted simulations involving context aware and non-context aware routing scenarios. The results indicate that the context aware routing outperforms other conventional request-routing techniques. The work presented here can impact routing algorithms, as well as address problems related to enterprise staffing and temporal variation of context for the agent.\",\n \"Title: Smart societies: from citizens as sensors to collective action\\nYear: 2013\\n\\nAbstract: Social media has become globally ubiquitous, transforming how people are networked and mobilized. This forum explores research and applications of these new networked publics at individual, organizational, and societal levels. Shelly Farnham, Editor\",\n \"Title: Unfolding the event landscape on twitter: classification and exploration of user categories\\nYear: 2012\\n\\nAbstract: Social media platforms such as Twitter garner significant attention from very large audiences in response to real-world events. Automatically establishing who is participating in information production or conversation around events can improve event content consumption, help expose the stakeholders in the event and their varied interests, and even help steer subsequent coverage of an event by journalists. In this paper, we take initial steps towards building an automatic classifier for user types on Twitter, focusing on three core user categories that are reflective of the information production and consumption processes around events: organizations, journalists/media bloggers, and ordinary individuals. Exploration of the user categories on a range of events shows distinctive characteristics in terms of the proportion of each user type, as well as differences in the nature of content each shared around the events.\",\n \"Title: Temporal patterns in social media streams: Theme discovery and evolution using joint analysis of content and context\\nYear: 2009\\n\\nAbstract: Online social networking sites such as Flickr and Facebook provide a diverse range of functionalities that foster online communities to create and share media content. In particular, Flickr groups are increasingly used to aggregate and share photos about a wide array of topics or themes. Unlike photo repositories where images are typically organized with respect to static topics, the photo sharing process as in Flickr often results in complex time-evolving social and visual patterns. Characterizing such time-evolving patterns can enrich media exploring experience in a social media repository. In this paper, we propose a novel framework that characterizes distinct time-evolving patterns of group photo streams. We use a nonnegative joint matrix factorization approach to incorporate image content features and contextual information, including associated tags, photo owners and post times. In our framework, we consider a group as a mixture of themes - each theme exhibits similar patterns of image content and context. The theme extraction is to best explain the observed image content features and associations with tags, users and times. Extensive experiments on a Flickr dataset suggest that our approach is able to extract meaningful evolutionary patterns from group photo streams. We evaluate our method through a tag prediction task. Our prediction results outperform baseline methods, which indicate the utility of our theme based joint analysis.\",\n \"Title: Creepy but inevitable?: the evolution of social networking\\nYear: 2014\\n\\nAbstract: This paper focuses on the fifth year of a cross-sectional trend study of enterprise social networking. Several stable patterns are evident--some activities have plateaued, others steadily increase in frequency. The fifth year did see a new development: As social networking companies visibly embraced behavior tracking and targeted advertising, concerns shifted from boundary regulation within personal networks to unsettling evidence of activity monitoring. However, benefits of use continue to outweigh drawbacks.\",\n \"Title: Seeking and sharing health information online: comparing search engines and social media\\nYear: 2014\\n\\nAbstract: Search engines and social media are two of the most com-monly used online services; in this paper, we examine how users appropriate these platforms for online health activi-ties via both large-scale log analysis and a survey of 210 people. While users often turn to search engines to learn about serious or highly stigmatic conditions, a surprising amount of sensitive health information is also sought and shared via social media, in our case the public social plat-form Twitter. We contrast what health content people seek via search engines vs. share on social media, as well as why they choose a particular platform for online health activi-ties. We reflect on the implications of our results for design-ing search engines, social media, and social search tools that better support people's health information seeking and sharing needs.\",\n \"Title: Modeling and predicting group activity over time in online social media\\nYear: 2009\\n\\nAbstract: This paper develops a probabilistic framework that can model and predict group activity over time on online social media. Users of social media sites such as Flickr often face the enormous challenge of which group to choose, due to the presence of numerous competing groups of similar content. Determining an empirical measure of significance of a group can help tackle this problem. The proposed framework therefore determines an optimal measure per group based on past user participation and interaction as well as likely future activity in the group. The framework is tested on a Flickr dataset and the results show that this method can yield satisfactory predictions of group activity. This implies that the computed measure of significance of a group can be used by end users to choose groups with rich activity.\",\n \"Title: Detecting and Characterizing Mental Health Related Self-Disclosure in Social Media\\nYear: 2015\\n\\nAbstract: Self-disclosure is an important element facilitating improved psychological wellbeing in individuals with mental illness. As social media is increasingly adopted in health related discourse, we examine how these new platforms might be allowing honest and candid expression of thoughts, experiences and beliefs. Specifically, we seek to detect levels of self-disclosure manifested in posts shared on different mental health forums on Reddit. We develop a classifier for the purpose based on content features. The classifier is able to characterize a Reddit post to be of high, low, or no self-disclosure with 78% accuracy. Applying this classifier to general mental health discourse on Reddit, we find that bulk of such discourse is characterized by high self-disclosure, and that the community responds distinctively to posts that disclose less or more. We conclude with the potential of harnessing our proposed self-disclosure detection algorithm in psychological therapy via social media. We also discuss design considerations for improved community moderation and support in these vulnerable self-disclosing communities.\",\n \"Title: Anorexia on Tumblr: A Characterization Study\\nYear: 2015\\n\\nAbstract: Eating disorders, such as anorexia nervosa are a major health concern affecting many young individuals. Given the extensive adoption of social media technologies in the anorexia affected demographic, we study behavioral characteristics of this population focusing on the social media Tumblr. Aligned with observations in prior literature, we find the presence of two prominent anorexia related communities on Tumblr -- pro-anorexia and pro-recovery. Empirical analyses on several thousand Tumblr posts show use of the site as a media-rich platform replete with triggering content for enacting anorexia as a lifestyle choice. Through use of common pro-anorexia tags, the pro-recovery community however attempts to \\\\\\\"permeate\\\\\\\" into the pro-anorexia community to educate them of the health risks of anorexia. Further, the communities exhibit distinctive affective, social, cognitive, and linguistic style markers. Compared with recover- ing anorexics, pro-anorexics express greater negative affect, higher cognitive impairment, and greater feelings of social isolation and self-harm. We also observe that these characteristics may be used in a predictive setting to detect anorexia content with 80% accuracy. Based on our findings, clinical implications of detecting anorexia related content on social media are discussed.\",\n \"Title: Quote RTs on Twitter: Usage of the New Feature for Political Discourse.\\nYear: 2016\\n\\nAbstract: Social media platforms provide several social interactional features. Due to the large scale reach of social media, these interactional features help enable various types of political discourse. Constructive and diversified discourse is important for sustaining healthy communities and reducing the impact of echo chambers. In this paper, we empirically examine the role of a newly introduced Twitter feature, 'quote retweets' (or 'quote RTs') in political discourse, specifically whether it has led to improved, civil, and balanced exchange. Quote RTs allow users to quote the tweet they retweet, while adding a short comment. Our analysis using content, network and crowd labeled data indicates that the feature has increased political discourse and its diffusion, compared to existing features. We discuss the implications of our findings in understanding and reducing online polarization.\",\n \"Title: Psychological Effects of Urban Crime Gleaned from Social Media\\nYear: 2015\\n\\nAbstract: Exposure to frequent crime incidents has been found to have a negative bearing on the well-being of city residents, even if they are not themselves a direct victim. We pursue the research question of whether naturalistic data shared on Twitter may provide a \\\"lens\\\" to understand changes in psychological attributes of urban communities (1) immediately following crime incidents, as well as (2) due to long-term exposure to crime. We analyze half a million Twitter posts from the City of Atlanta in 2014, where the rate of violent crime is three times of the national average. In a first study, we develop a statistical method to detect changes in social media psychological attributes in the immediate aftermath of a crime event. Second, we develop a regression model that uses historical (yearlong) crime to predict Twitter negative emotion, anxiety, anger, and sadness. We do not find significant changes in social media affect immediately following crime in Atlanta. However we do observe significant ability of historical crime to account for heightened negative emotion and anger in the future. Our findings have implications in gauging the utility of social media to infer longitudinal and population-scale patterns of urban well-being.\",\n \"Title: Measuring and Characterizing Nutritional Information of Food and Ingestion Content in Instagram\\nYear: 2015\\n\\nAbstract: Social media sites like Instagram have emerged as popular platforms for sharing ingestion and dining experiences. However research on characterizing the nutritional information embedded in such content is limited. In this paper, we develop a computational method to extract nutritional information, specifically calorific content from Instagram food posts. Next, we explore how the community reacts specifically to healthy versus non-healthy food postings. Based on a crowdsourced approach, our method was found to detect calorific content in posts with 89% accuracy. We further show the use of Instagram as a platform where sharing of moderately healthy food content is common, and such content also receives the most support from the community.\",\n \"Title: Identity Management and Mental Health Discourse in Social Media\\nYear: 2015\\n\\nAbstract: Social media is increasingly being adopted in health discourse. We examine the role played by identity in supporting discourse on socially stigmatized conditions. Specifically, we focus on mental health communities on reddit. We investigate the characteristics of mental health discourse manifested through reddit's characteristic 'throwaway' accounts, which are used as proxies of anonymity. For the purpose, we propose affective, cognitive, social, and linguistic style measures, drawing from literature in psychology. We observe that mental health discourse from throwaways is considerably disinhibiting and exhibits increased negativity, cognitive bias and self-attentional focus, and lowered self-esteem. Throwaways also seem to be six times more prevalent as an identity choice on mental health forums, compared to other reddit communities. We discuss the implications of our work in guiding mental health interventions, and in the design of online communities that can better cater to the needs of vulnerable populations. We conclude with thoughts on the role of identity manifestation on social media in behavioral therapy.\",\n \"Title: #thyghgapp: Instagram Content Moderation and Lexical Variation in Pro-Eating Disorder Communities.\\nYear: 2016\\n\\nAbstract: Pro-eating disorder (pro-ED) communities on social media encourage the adoption and maintenance of disordered eating habits as acceptable alternative lifestyles rather than threats to health. In particular, the social networking site Instagram has reacted by banning searches on several pro-ED tags and issuing content advisories on others. We pre-sent the first large-scale quantitative study investigating pro-ED communities on Instagram in the aftermath of moderation -- our dataset contains 2.5M posts between 2011 and 2014. We find that the pro-ED community has adopted non-standard lexical variations of moderated tags to circumvent these restrictions. In fact, increasingly complex lexical variants have emerged over time. Communities that use lexical variants show increased participation and support of pro-ED (15-30%). Finally, the tags associated with content on these variants express more toxic, self-harm, and vulnerable content. Despite Instagramâs moderation strategies, pro-ED communities are active and thriving. We discuss the effectiveness of content moderation as an intervention for communities of deviant behavior.\",\n \"Title: Characterizing Dietary Choices, Nutrition, and Language in Food Deserts via Social Media.\\nYear: 2016\\n\\nAbstract: Social media has emerged as a promising source of data for public health. This paper examines how these platforms can provide empirical quantitative evidence for understanding dietary choices and nutritional challenges in “food deserts” -- Census tracts characterized by poor access to healthy and affordable food. We present a study of 3 million food related posts shared on Instagram, and observe that content from food deserts indicate consumption of food high in fat, cholesterol and sugar; a rate higher by 5-17% compared to non-food desert areas. Further, a topic model analysis reveals the ingestion language of food deserts to bear distinct attributes. Finally, we investigate to what extent Instagram ingestion language is able to infer whether a tract is a food desert. We find that a predictive model that uses ingestion topics, socio-economic and food deprivation status attributes yields high accuracy (u003e80%) and improves over baseline methods by 6-14%. We discuss the role of social media in helping address inequalities in food access and health.\",\n \"Title: Quantifying and Predicting Mental Illness Severity in Online Pro-Eating Disorder Communities.\\nYear: 2016\\n\\nAbstract: Social media sites have struggled with the presence of emotional and physical self-injury content. Individuals who share such content are often challenged with severe mental illnesses like eating disorders. We present the first study quantifying levels of mental illness severity (MIS) in social media. We examine a set of users on Instagram who post content on pro-eating disorder tags (26M posts from 100K users). Our novel statistical methodology combines topic modeling and novice/clinician annotations to infer MIS in a userâ s content. Alarmingly, we find that proportion of users whose content expresses high MIS have been on the rise since 2012 (13%/year increase). Previous MIS in a userâ s content over seven months can predict future risk with 81% accuracy. Our model can also forecast MIS levels up to eight months in the future with performance better than baseline. We discuss the health outcomes and design implications as well as ethical considerations of this line of research.\",\n \"Title: Social Media for Mental Illness Risk Assessment, Prevention and Support\\nYear: 2015\\n\\nAbstract: Social media sites are continually creating rich repositories of information relating to our activities, emotion and linguistic expression. In this talk I will discuss how such trails of data may be harnessed to reason about our mental health concerns. First, I will discuss a series of studies that examined how cues derived from social media around major life events (e.g., childbirth) and societal disruptions (e.g., violence) may help infer risks to well-being. Second, I will discuss threads of research in which we investigated the role of social media systems in providing a platform of expression to distressed communities and communities exhibiting deviant health behaviors. Broadly, I will reflect on how this new line of research bears potential in informing the design of interventions for improved well-being, privacy and ethical considerations, and in this context, the challenges and opportunities of the increasing ubiquity of social media.\",\n \"Title: Detecting Changes in Suicide Content Manifested in Social Media Following Celebrity Suicides\\nYear: 2015\\n\\nAbstract: The Werther effect describes the increased rate of completed or attempted suicides following the depiction of an individual's suicide in the media, typically a celebrity. We present findings on the prevalence of this effect in an online platform: r/SuicideWatch on Reddit. We examine both the posting activity and post content after the death of ten high-profile suicides. Posting activity increases following reports of celebrity suicides, and post content exhibits considerable changes that indicate increased suicidal ideation. Specifically, we observe that post-celebrity suicide content is more likely to be inward focused, manifest decreased social concerns, and laden with greater anxiety, anger, and negative emotion. Topic model analysis further reveals content in this period to switch to a more derogatory tone that bears evidence of self-harm and suicidal tendencies. We discuss the implications of our findings in enabling better community support to psychologically vulnerable populations, and the potential of building suicide prevention interventions following high-profile suicides.\",\n \"Title: Characterizing Smoking and Drinking Abstinence from Social Media.\\nYear: 2015\\n\\nAbstract: Social media has been established to bear signals relating to health and well-being states. In this paper, we investigate the potential of social media in characterizing and understanding abstinence from tobacco or alcohol use. While the link between behavior and addiction has been explored in psychology literature, the lack of longitudinal self-reported data on long-term abstinence has challenged addiction research. We leverage the activity spanning almost eight years on two prominent communities on Reddit: StopSmoking and StopDrinking. We use the self-reported \\\"badge\\\" information of nearly a thousand users as gold standard information on their abstinence status to characterize long-term abstinence. We build supervised learning based statistical models that use the linguistic features of the content shared by the users as well as the network structure of their social interactions. Our findings indicate that long-term abstinence from smoking or drinking (~one year) can be distinguished from short-term abstinence (~40 days) with 85% accuracy. We further show that language and interaction on social media offer powerful cues towards characterizing these addiction-related health outcomes. We discuss the implications of our findings in social media and health research, and in the role of social media as a platform for positive behavior change and therapy.\",\n \"Title: Understanding Social Media Disclosures of Sexual Abuse Through the Lenses of Support Seeking and Anonymity.\\nYear: 2016\\n\\nAbstract: Support seeking in stigmatized contexts is useful when the discloser receives the desired response, but it also entails social risks. Thus, people do not always disclose or seek support when they need it. One such stigmatized context for support seeking is sexual abuse. In this paper, we use mixed methods to understand abuse-related posts on reddit. First, we take a qualitative approach to understand post content. Then we use quantitative methods to investigate the use of \\\"throwaway\\\" accounts, which provide greater anonymity, and report on factors associated with support seeking and first-time disclosures. In addition to significant linguistic differences between throwaway and identified accounts, we find that those using throwaway accounts are significantly more likely to engage in seeking support. We also find that men are significantly more likely to use throwaway accounts when posting about sexual abuse. Results suggest that subreddit moderators and members who wish to provide support pay attention to throwaway accounts, and we discuss the importance of context-specific anonymity in support seeking.\",\n \"Title: Recovery Amid Pro-Anorexia: Analysis of Recovery in Social Media.\\nYear: 2016\\n\\nAbstract: Online communities can promote illness recovery and improve well-being in the cases of many kinds of illnesses. However, for challenging mental health condition like anorexia, social media harbor both recovery communities as well as those that encourage dangerous behaviors. The effectiveness of such platforms in promoting recovery despite housing both communities is underexplored. Our work begins to fill this gap by developing a statistical framework using survival analysis and situating our results within the cognitive behavioral theory of anorexia. This model identifies content and participation measures that predict the likelihood of recovery. From our dataset of over 68M posts and 10K users that self-identify with anorexia, we find that recovery on Tumblr is protracted - only half of the population is estimated to exhibit signs of recovery after four years. We discuss the effectiveness of social media in improving well-being around anorexia, a unique health challenge, and emergent questions from this line of work.\",\n \"Title: \\\"This Post Will Just Get Taken Down\\\": Characterizing Removed Pro-Eating Disorder Social Media Content.\\nYear: 2016\\n\\nAbstract: Social media sites like Facebook and Instagram remove content that is against community guidelines or is perceived to be deviant behavior. Users also delete their own content that they feel is not appropriate within personal or community norms. In this paper, we examine characteristics of over 30,000 pro-eating disorder (pro-ED) posts that were at one point public on Instagram but have since been removed. Our work shows that straightforward signals can be found in deleted content that distinguish them from other posts, and that the implications of such classification are immense. We build a classifier that compares public pro-ED posts with this removed content that achieves moderate accuracy of 69%. We also analyze the characteristics in content in each of these post categories and find that removed content reflects more dangerous actions, self-harm tendencies, and vulnerability than posts that remain public. Our work provides early insights into content removal in a sensitive community and addresses the future research implications of the findings.\",\n \"Title: Discovering Shifts to Suicidal Ideation from Mental Health Content in Social Media.\\nYear: 2016\\n\\nAbstract: History of mental illness is a major factor behind suicide risk and ideation. However research efforts toward characterizing and forecasting this risk is limited due to the paucity of information regarding suicide ideation, exacerbated by the stigma of mental illness. This paper fills gaps in the literature by developing a statistical methodology to infer which individuals could undergo transitions from mental health discourse to suicidal ideation. We utilize semi-anonymous support communities on Reddit as unobtrusive data sources to infer the likelihood of these shifts. We develop language and interactional measures for this purpose, as well as a propensity score matching based statistical approach. Our approach allows us to derive distinct markers of shifts to suicidal ideation. These markers can be modeled in a prediction framework to identify individuals likely to engage in suicidal ideation in the future. We discuss societal and ethical implications of this research.\",\n \"Title: Social Media Participation in an Activist Movement for Racial Equality.\\nYear: 2016\\n\\nAbstract: From the Arab Spring to the Occupy Movement, social media has been instrumental in driving and supporting socio-political movements throughout the world. In this paper, we present one of the first social media investigations of an activist movement around racial discrimination and police violence, known as \\\"Black Lives Matter\\\". Considering Twitter as a sensor for the broader community's perception of the events related to the movement, we study participation over time, the geographical differences in this participation, and its relationship to protests that unfolded on the ground. We find evidence for continued participation across four temporally separated events related to the movement, with notable changes in engagement and language over time. We also find that participants from regions of historically high rates of black victimization due to police violence tend to express greater negativity and make more references to loss of life. Finally, we observe that social media attributes of affect, behavior and language can predict future protest participation on the ground. We discuss the role of social media in enabling collective action around this unique movement and how social media platforms may help understand perceptions on a socially contested and sensitive issue like race.\",\n \"Title: Opportunities and Challenges of Social Media in Personal and Societal Well-being\\nYear: 2016\\n\\nAbstract: Social media platforms have emerged as rich repositories of information relating to our activities, emotion and linguistic expression. In this talk I will discuss how this data may be harnessed to reason about our well-being. First, I will discuss a series of projects that examine how cues derived from social media around life-altering events (e.g., giving birth to a child, experience of abuse) and societal disruptions (e.g., urban violence, socio-political unrest) may help infer risks to mental health challenges. Second, I will discuss the emergent role of social media in providing a platform of self-disclosure and support to distressed, vulnerable, and under-privileged communities. Broadly, I will reflect on how this new line of research bears potential in informing the design of timely and tailored interventions, provisions for improved personal and societal well-being assessment, privacy and ethical considerations, and in this context, the challenges and opportunities of the increasing ubiquity of social media.\",\n \"Title: Social Media for Safety: Characterizing Online Interactions Between Citizens and Police.\\nYear: 2016\\n\\nAbstract: Social media has emerged as a promising resource for police to connect with citizens for collective action. However the attributes of police citizen interactions on social media remain under-explored. In this paper, we utilise official and public Facebook pages of several police departments in India to study the patterns of engagement, emotions, and social processes between citizens and police in the context of day-to-day policing. We examine two prominent discussion threads: police initiated and citizen initiated. We find that topics exchanged in police initiated discussions are more focussed than citizen initiated threads; police focused on topics concerning safety awareness programs, action reports, and information regarding policing activities. Compared to police initiated discussions, citizen initiated discussions show lower engagement. Further, discussions involving both police and citizens show higher negative emotions, anger and arousal than citizen only discussions; these interventions involving both reveal a stronger notion of a collective identity. We discuss the implications of our work in designing technological support for improved policing and to help understand citizen opinions, safety concerns and well-being via social media.\",\n \"Title: Computational Approaches Toward Integrating Quantified Self Sensing and Social Media.\\nYear: 2017\\n\\nAbstract: The growing amount of data collected by quantified self tools and social media hold great potential for applications in personalized medicine. Whereas the first includes health-related physiological signals, the latter provides insights into a user's behavior. However, the two sources of data have largely been studied in isolation. We analyze public data from users who have chosen to connect their MyFitnessPal and Twitter accounts. We show that a user's diet compliance success, measured via their self-logged food diaries, can be predicted using features derived from social media: linguistic, activity, and social capital. We find that users with more positive affect and a larger social network are more successful in succeeding in their dietary goals. Using a Granger causality methodology, we also show that social media can help predict daily changes in diet compliance success or failure with an accuracy of 77%, that improves over baseline techniques by 17%. We discuss the implications of our work in the design of improved health interventions for behavior change.\",\n \"Title: Gender and Cross-Cultural Differences in Social Media Disclosures of Mental Illness.\\nYear: 2017\\n\\nAbstract: Cultural and gender norms shape how mental illness and therapy are perceived. However, there is a paucity of adequate empirical evidence around gender and cultural dimensions of mental illness. In this paper we situate social media as a \\\\\\\"lens\\\\\\\" to examine these dimensions. We focus on a large dataset of individuals who self-disclose to have an underlying mental health concern on Twitter. Having identified genuine disclosures in this data via semi-supervised learning, we examine differences in their posts, as measured via linguistic attributes and topic models. Our findings reveal significant differences between the content shared by female and male users, and by users from two western and two majority world countries. Males express higher negativity and lower desire for social support, whereas majority world users demonstrate more inhibition in their expression. We discuss the implications of our work in providing insights into the relationship of gender and culture with mental health, and in the design of gender and culture-aware health interventions.\",\n \"Title: A Social Media Based Index of Mental Well-Being in College Campuses.\\nYear: 2017\\n\\nAbstract: Psychological distress in the form of depression, anxiety and other mental health challenges among college students is a growing health concern. Dearth of accurate, continuous, and multi-campus data on mental well-being presents significant challenges to intervention and mitigation efforts in college campuses. We examine the potential of social media as a new \\\\\\\"barometer\\\\\\\" for quantifying the mental well-being of college populations. Utilizing student-contributed data in Reddit communities of over 100 universities, we first build and evaluate a transfer learning based classification approach that can detect mental health expressions with 97% accuracy. Thereafter, we propose a robust campus-specific Mental Well-being Index: MWI. We find that MWI is able to reveal meaningful temporal patterns of mental well-being in campuses, and to assess how their expressions relate to university attributes like size, academic prestige, and student demographics. We discuss the implications of our work for improving counselor efforts, and in the design of tools that can enable better assessment of the mental health climate of college campuses.\",\n \"Title: CHI-nnabis: Implications of Marijuana Legalization for and from Human-Computer Interaction.\\nYear: 2017\\n\\nAbstract: The consumption of cannabis has substantial implications for medicine, popular culture, and technology use, yet discussion of it is almost entirely absent in the HCI literature. Taking advantage of CHI 2017's location in one of the first jurisdictions to legalize recreational use of marijuana in the U.S., this panel will discuss its socio-technical implications, identify HCI research themes relevant to policy and public health debates, and outline a research agenda.\",\n \"Title: Modeling and Understanding Visual Attributes of Mental Health Disclosures in Social Media.\\nYear: 2017\\n\\nAbstract: Content shared on social media platforms has been identified to be valuable in gaining insights into people's mental health experiences. Although there has been widespread adoption of photo-sharing platforms such as Instagram in recent years, the role of visual imagery as a mechanism of self-disclosure is less understood. We study the nature of visual attributes manifested in images relating to mental health disclosures on Instagram. Employing computer vision techniques on a corpus of thousands of posts, we extract and examine three visual attributes: visual features (e.g., color), themes, and emotions in images. Our findings indicate the use of imagery for unique self-disclosure needs, quantitatively and qualitatively distinct from those shared via the textual modality: expressions of emotional distress, calls for help, and explicit display of vulnerability. We discuss the relationship of our findings to literature in visual sociology, in mental health self disclosure, and implications for the design of health interventions.\",\n \"Title: Multimodal Classification of Moderated Online Pro-Eating Disorder Content.\\nYear: 2017\\n\\nAbstract: Social media sites are challenged by both the scale and variety of deviant behavior online. While algorithms can detect spam and obscenity, behaviors that break community guidelines on some sites are difficult because they have multimodal subtleties (images and/or text). Identifying these posts is often regulated to a few moderators. In this paper, we develop a deep learning classifier that jointly models textual and visual characteristics of pro-eating disorder content that violates community guidelines. Using a million Tumblr photo posts, our classifier discovers deviant content efficiently while also maintaining high recall (85%). Our approach uses human sensitivity throughout to guide the creation, curation, and understanding of this approach to challenging, deviant content. We discuss how automation might impact community moderation, and the ethical and social obligations of this area.\",\n \"Title: How to Handle Online Risks?: Discussing Content Curation and Moderation in Social Media.\\nYear: 2017\\n\\nAbstract: Amidst proliferation of online negativity and harmful content such as fake news and harassment on social media, this panel will be an active discussion of the potential roles of various actors in sociotechnical systems in curating, moderating, and studying content. Should companies intervene? Why or why not, and if so, to what extent? What role do academics play in this process and how does it affect research processes? Our multidisciplinary panelists represent humanities, computer science, law, and media psychology. They will share perspectives based on their own research and interact with the audience to discuss varied perspectives around these central questions. A primary goal is to think about how, moving forward, these issues affect HCI research.\",\n \"Title: The Language of Social Support in Social Media and Its Effect on Suicidal Ideation Risk.\\nYear: 2017\\n\\nAbstract: Online social support is known to play a significant role in mental well-being. However, current research is limited in its ability to quantify this link. Challenges exist due to the paucity of longitudinal, pre- and post mental illness risk data, and reliable methods that can examine causality between past availability of support and future risk. In this paper, we propose a method to measure how the language of comments in Reddit mental health communities influences risk to suicidal ideation in the future. Incorporating human assessments in a stratified propensity score analysis based framework, we identify comparable subpopulations of individuals and measure the effect of online social support language. We interpret these linguistic cues with an established theoretical model of social support, and find that esteem and network support play a more prominent role in reducing forthcoming risk. We discuss the implications of our work for designing tools that can improve support provisions in online communities.\",\n \"Title: Analysis of Smoking and Drinking Relapse in an Online Community.\\nYear: 2017\\n\\nAbstract: Online communities and social media are known to play an important role in improving health efficacy and well-being. In this paper, we examine the role of such platforms in promoting smoking and drinking cessation. We focus on two support communities on Reddit, StopSmoking and StopDrinking, to analyze relapse events among several thousand individuals. For this purpose, we formulate and identify the key engagement and linguistic characteristics of abstainers and relapsers based on participation in the communities spanning almost nine years, and we employ a robust statistical methodology based on survival analysis to examine how participation and these characteristics relate to likelihood of relapse. Our results show that half of the population is at a high risk of relapse within 1-2 months of cessation attempts; however, individuals who continue to abstain beyond three years tend to maintain high likelihood of sustained abstinence. Furthermore, we find positive affect and increased social engagement to be predictors of abstinence. We discuss the implications of our work in tracking effectiveness of online health communities and for designing health interventions.\",\n \"Title: Inferring Mood Instability on Social Media by Leveraging Ecological Momentary Assessments.\\nYear: 2017\\n\\nAbstract: Active and passive sensing technologies are providing powerful mechanisms to track, model, and understand a range of health behaviors and well-being states. Despite yielding rich, dense and high fidelity data, current sensing technologies often require highly engineered study designs and persistent participant compliance, making them difficult to scale to large populations and to data acquisition tasks spanning extended time periods. This paper situates social media as a new passive, unobtrusive sensing technology. We propose a semi-supervised machine learning framework to combine small samples of data gathered through active sensing, with large-scale social media data to infer mood instability (MI) in individuals. Starting from a theoretically-grounded measure of MI obtained from mobile ecological momentary assessments (EMAs), we show that our model is able to infer MI in a large population of Twitter users with 96% accuracy and F-1 score. Additionally, we show that, our model predicts self-identifying Twitter users with bipolar and borderline personality disorder to exhibit twice the likelihood of high MI, compared to that in a suitable control. We discuss the implications and the potential for integrating complementary sensing capabilities to address complex research challenges in precision medicine.\",\n \"Title: Norms Matter: Contrasting Social Support Around Behavior Change in Online Weight Loss Communities\\nYear: 2018\\n\\nAbstract: ABSTRACTOnline health communities (OHCs) provide support across conditions; for weight loss, OHCs offer support to foster positive behavior change. However, weight loss behaviors can also be subverted on OHCs to promote disordered eating practices. Using comments as proxies for support, we use computational linguistic methods to juxtapose similarities and differences in two Reddit weight loss communities, r/proED and r/loseit. We employ language modeling and find that word use in both communities is largely similar. Then, by building a word embedding model, specifically a deep neural network on comment words, we contrast the context of word use and find differences that imply different behavior change goals in these OHCs. Finally, these content and context norms predict whether a comment comes from r/proED or r/loseit. We show that norms matter in understanding how different OHCs provision support to promote behavior change and discuss the implications for design and moderation of OHCs.\",\n \"Title: Mental Health Support and its Relationship to Linguistic Accommodation in Online Communities\\nYear: 2018\\n\\nAbstract: ABSTRACTMany online communities cater to the critical and unmet needs of individuals challenged with mental illnesses. Generally, communities engender characteristic linguistic practices, known as norms. Conformance to these norms, or linguistic accommodation, encourages social approval and acceptance. This paper investigates whether linguistic accommodation impacts a specific social feedback: the support received by an individual in an online mental health community. We first quantitatively derive two measures for each post in these communities: 1) the linguistic accommodation it exhibits, and 2) the level of support it receives. Thereafter, we build a statistical framework to examine the relationship between these measures. Although the extent to which accommodation is associated with support varies, we find a positive link between the two, consistent across 55 Reddit communities serving various psychological needs. We discuss how our work surfaces a tension in the functioning of these sensitive communities, and present design implications for improving their support provisioning mechanisms.\",\n \"Title: Relationship breakup disclosures and media ideologies on Facebook.\\nYear: 2018\\n\\nAbstract: After relationship breakups, people must make difficult decisions about whether and how to convey this change in a networked environment. To understand and characterize behaviors around breakup disclosures, we analyzed survey responses from 119 US Facebook users who reported experiencing a recent breakup. Using mixed methods, we find that those perceiving Facebook as a more efficient disclosure medium are more likely to announce breakups. We show how media ideologies around Facebook breakup disclosures vary; yet people assume others hold similar beliefs about what is appropriate. We contribute to self-disclosure and online identity literature by identifying two new ways people engage in disclosure and self-presentation on social media: announcements, which highlight how social media can serve as efficient one-to-many disclosure sources, and private status change behaviors, a reflexive means of self-presentation. Understanding breakup disclosures provides insight into designing social media to better enable users to find support during difficult life transitions.\",\n \"Title: A Social Media Based Examination of the Effects of Counseling Recommendations after Student Deaths on College Campuses.\\nYear: 2018\\n\\nAbstract: Student deaths on college campuses, whether brought about by a suicide or an uncontrollable incident, have serious repercussions for the mental wellbeing of students. Consequently, many campus administrators implement post-crisis intervention measures to promote student-centric mental health support. Information about these measures, which we refer to as \\\"\\\", are often shared via electronic channels, including social media. However, the current ability to assess the effects of these recommendations on post-crisis psychological states is limited. We propose a causal analysis framework to examine the effects of these counseling recommendations after student deaths. We leverage a dataset from 174 Reddit campus communities and ~400M posts of ~350K users. Then we employ statistical modeling and natural language analysis to quantify the psychosocial shifts in behavioral, cognitive, and affective expression of grief in individuals who are \\\"exposed\\\" to (comment on) the counseling recommendations, compared to that in a matched control cohort. Drawing on crisis and psychology research, we find that the exposed individuals show greater grief, psycholinguistic, and social expressiveness, providing evidence of a healing response to crisis and thereby positive psychological effects of the counseling recommendations. We discuss the implications of our work in supporting post-crisis rehabilitation and intervention efforts on college campuses.\",\n \"Title: Social Support, Reciprocity, and Anonymity in Responses to Sexual Abuse Disclosures on Social Media.\\nYear: 2018\\n\\nAbstract: Seeking and providing support is challenging. When people disclose sensitive information, audience responses can substantially impact the discloser's wellbeing. We use mixed methods to understand responses to online sexual abuse-related disclosures on Reddit. We characterize disclosure responses, then investigate relationships between post content, comment content, and anonymity. We illustrate what types of support sought and provided in posts and comments co-occur. We find that posts seeking support receive more comments, and comments from “throwaway” (i.e., anonymous) accounts are more likely on posts also from throwaway accounts. Anonymous commenting enables commenters to share intimate content such as reciprocal disclosures and supportive messages, and commenter anonymity is not associated with aggressive or unsupportive comments. We argue that anonymity is an essential factor in designing social technologies that facilitate support seeking and provision in socially stigmatized contexts, and provide implications for social media site design. CAUTION: This article includes content about sexual abuse.\",\n \"Title: A Taxonomy of Ethical Tensions in Inferring Mental Health States from Social Media.\\nYear: 2019\\n\\nAbstract: Powered by machine learning techniques, social media provides an unobtrusive lens into individual behaviors, emotions, and psychological states. Recent research has successfully employed social media data to predict mental health states of individuals, ranging from the presence and severity of mental disorders like depression to the risk of suicide. These algorithmic inferences hold great potential in supporting early detection and treatment of mental disorders and in the design of interventions. At the same time, the outcomes of this research can pose great risks to individuals, such as issues of incorrect, opaque algorithmic predictions, involvement of bad or unaccountable actors, and potential biases from intentional or inadvertent misuse of insights. Amplifying these tensions, there are also divergent and sometimes inconsistent methodological gaps and under-explored ethics and privacy dimensions. This paper presents a taxonomy of these concerns and ethical challenges, drawing from existing literature, and poses questions to be resolved as this research gains traction. We identify three areas of tension: ethics committees and the gap of social media research; questions of validity, data, and machine learning; and implications of this research for key stakeholders. We conclude with calls to action to begin resolving these interdisciplinary dilemmas.\",\n \"Title: What (or Who) Is Public?: Privacy Settings and Social Media Content Sharing.\\nYear: 2017\\n\\nAbstract: When social networking sites give users granular control over their privacy settings, the result is that some content across the site is public and some is not. How might this content--or characteristics of users who post publicly versus to a limited audience--be different? If these differences exist, research studies of public content could potentially be introducing systematic bias. Via Mechanical Turk, we asked 1,815 Facebook users to share recent posts. Using qualitative coding and quantitative measures, we characterize and categorize the nature of the content. Using machine learning techniques, we analyze patterns of choices for privacy settings. Contrary to expectations, we find that content type is not a significant predictor of privacy setting; however, some demographics such as gender and age are predictive. Additionally, with consent of participants, we provide a dataset of nearly 9,000 public and non-public Facebook posts.\",\n \"Title: Integrating Artificial and Human Intelligence in Complex, Sensitive Problem Domains: Experiences from Mental Health\\nYear: 2018\\n\\nAbstract: This article presents a position highlighting the importance of combining artificial intelligence approaches with human intelligence, in other words, the involvement of humans. To do so, we specifically focus on problems of societal significance, stemming from complex, sensitive domains. We first discuss our prior work across a series of projects surrounding social media and mental health, and identify major themes for which augmentation of AI systems and techniques with human feedback has been and can be fruitful and meaningful. We then conclude by noting the implications, in terms of opportunities as well as challenges, that can be drawn from our position, both relating to the specific domain of mental health and for AI researchers and practitioners.\",\n \"Title: Discovering Alternative Treatments for Opioid Use Recovery Using Social Media.\\nYear: 2019\\n\\nAbstract: Opioid use disorder (OUD) poses substantial risks to personal well-being and public health. In online communities, users support those seeking recovery, in part by promoting clinically grounded treatments. However, some communities also promote clinically unverified OUD treatments, such as unregulated and untested drugs. Little research exists on which alternative treatments people use, whether these treatments are effective for recovery, or if they cause negative side effects. We provide the first large-scale social media study of clinically unverified, alternative treatments in OUD recovery on Reddit, partnering with an addiction research scientist. We adopt transfer learning across 63 subreddits to precisely identify posts related to opioid recovery. Then, we quantitatively discover potential alternative treatments and contextualize their effectiveness. Our work benefits health research and practice by identifying undiscovered recovery strategies. We also discuss the impacts to online communities dealing with stigmatized behavior and research ethics.\",\n \"Title: Methodological Gaps in Predicting Mental Health States from Social Media - Triangulating Diagnostic Signals.\\nYear: 2019\\n\\nAbstract: A growing body of research is combining social media data with machine learning to predict mental health states of individuals. An implication of this research lies in informing evidence-based diagnosis and treatment. However, obtaining clinically valid diagnostic information from sensitive patient populations is challenging. Consequently, researchers have operationalized characteristic online behaviors as \\\"proxy diagnostic signals\\\" for building these models. This paper posits a challenge in using these diagnostic signals, purported to support clinical decision-making. Focusing on three commonly used proxy diagnostic signals derived from social media, we find that predictive models built on these data, although offer strong internal validity, suffer from poor external validity when tested on mental health patients. A deeper dive reveals issues of population and sampling bias, as well as of uncertainty in construct validity inherent in these proxies. We discuss the methodological and clinical implications of these gaps and provide remedial guidelines for future research.\",\n \"Title: Characterizing Homelessness Discourse on Social Media.\\nYear: 2019\\n\\nAbstract: Social media allows us to connect and maintain relationships in spite of physical distance and barriers; as computers and the internet become more accessible, hard-to-reach populations are finding a voice on these platforms. One such group is those who are or have been homeless. Through a computational linguistic analysis of a large corpus of Tumblr blog posts, this paper provides preliminary insights to understand the unique ways homeless bloggers express their needs, frustrations and financial/social distress, connect with others, and seek emotional and practical support from others. We highlight future investigations, building upon this research, that can be pursued in HCI to assist an underserved population with the difficult life experience of homelessness.\",\n \"Title: Where is the Human? - Bridging the Gap Between AI and HCI.\\nYear: 2019\\n\\nAbstract: In recent years, AI systems have become both more powerful and increasingly promising for integration in a variety of application areas. Attention has also been called to the social challenges these systems bring, particularly in how they might fail or even actively disadvantage marginalised social groups, or how their opacity might make them difficult to oversee and challenge. In the context of these and other challenges, the roles of humans working in tandem with these systems will be important, yet the HCI community has been only a quiet voice in these debates to date. This workshop aims to catalyse and crystallise an agenda around HCI's engagement with AI systems. Topics of interest include explainable and explorable AI; documentation and review; integrating artificial and human intelligence; collaborative decision making; AI/ML in HCI Design; diverse human roles and relationships in AI systems; and critical views of AI.\",\n \"Title: The Tesserae Project - Large-Scale, Longitudinal, In Situ, Multimodal Sensing of Information Workers.\\nYear: 2019\\n\\nAbstract: The Tesserae project investigates how a suite of sensors can measure workplace performance (e.g., organizational citizenship behavior), psychological traits (e.g., personality, affect), and physical characteristics (e.g., sleep, activity) over one year. We enrolled 757 information workers across the U.S. and measure heart rate, physical activity, sleep, social context, and other aspects through smartwatches, a phone agent, beacons, and social media. We report challenges that we faced with enrollment, privacy, and incentive structures while setting up such a long-term multimodal large-scale sensor study. We discuss the tradeoffs of remote versus in-person enrollment, and showed that directly paid, in-person enrolled participants are more compliant overall compared to remotely-enrolled participants. We find that providing detailed information regarding privacy concerns up-front is highly beneficial. We believe that our experiences can benefit other large sensor projects as this field grows.\",\n \"Title: Social Media as a Passive Sensor in Longitudinal Studies of Human Behavior and Wellbeing.\\nYear: 2019\\n\\nAbstract: Social media serves as a platform to share thoughts and connect with others. The ubiquitous use of social media also enables researchers to study human behavior as the data can be collected in an inexpensive and unobtrusive way. Not only does social media provide a passive means to collect historical data at scale, it also functions as a \\\"verbal\\\" sensor, providing rich signals about an individual's social ecological context. This case study introduces an infrastructural framework to illustrate the feasibility of passively collecting social media data at scale in the context of an ongoing multimodal sensing study of workplace performance (N=757). We study our dataset in its relationship with demographic, personality, and wellbeing attributes of individuals. Importantly, as a means to study selection bias, we examine what characterizes individuals who choose to consent to social media data sharing vs. those who do not. Our work provides practical experiences and implications for research in the HCI field who seek to conduct similar longitudinal studies that harness the potential of social media data.\",\n \"Title: Designing Dashboard for Campus Stakeholders to Support College Student Mental Health\\nYear: 2019\\n\\nAbstract: Stakeholders, such as college campus administrators and clinicians, are committed to alleviating students' mental health concerns and the campus' mental health climate, but they suffer from a lack of timely and actionable information. Research has revealed that student personal data, such as self-tracking and social media data, can provide in-situ insights about students' mental health states. However, how they can support stakeholders' goals remains unexplored. We examine the potential of user-centered technology in addressing this challenge. We interview campus administrators and clinicians to understand their needs and current practices. Then through a paper prototype, we gather design suggestions for stakeholder-facing dashboards. We discuss three design implications revealed through our studies: that social media can be a potentially useful resource for understanding student mental health despite concerns of data reliability and interpretability; that the dashboards need to assuage stakeholders' concerns around bias and intelligibility of the visual presentations, which can become barriers to future adoption; and that ethical considerations, particularly securing privacy of student data, need to be salient in the design.\",\n \"Title: A Social Media Study on the Effects of Psychiatric Medication Use.\\nYear: 2019\\n\\nAbstract: Understanding the effects of psychiatric medications during mental health treatment constitutes an active area of inquiry. While clinical trials help evaluate the effects of these medications, many trials suffer from a lack of generalizability to broader populations. We leverage social media data to examine psychopathological effects subject to self-reported usage of psychiatric medication. Using a list of common approved and regulated psychiatric drugs and a Twitter dataset of 300M posts from 30K individuals, we develop machine learning models to first assess effects relating to mood, cognition, depression, anxiety, psychosis, and suicidal ideation. Then, based on a stratified propensity score based causal analysis, we observe that use of specific drugs are associated with characteristic changes in an individual's psychopathology. We situate these observations in the psychiatry literature, with a deeper analysis of pre-treatment cues that predict treatment outcomes. Our work bears potential to inspire novel clinical investigations and to build tools for digital therapeutics.\",\n \"Title: Differentiating Higher and Lower Job Performers in the Workplace Using Mobile Sensing\\nYear: 2019\\n\\nAbstract: Assessing performance in the workplace typically relies on subjective evaluations, such as, peer ratings, supervisor ratings and self assessments, which are manual, burdensome and potentially biased. We use objective mobile sensing data from phones, wearables and beacons to study workplace performance and offer new insights into behavioral patterns that distinguish higher and lower performers when considering roles in companies (i.e., supervisors and non-supervisors) and different types of companies (i.e., high tech and consultancy). We present initial results from an ongoing year-long study of N=554 information workers collected over a period ranging from 2-8.5 months. We train a gradient boosting classifier that can classify workers as higher or lower performers with AUROC of 0.83. Our work opens the way to new forms of passive objective assessment and feedback to workers to potentially provide week by week or quarter by quarter guidance in the workplace.\",\n \"Title: Prevalence and Psychological Effects of Hateful Speech in Online College Communities.\\nYear: 2019\\n\\nAbstract: Background. Hateful speech bears negative repercussions and is particularly damaging in college communities. The efforts to regulate hateful speech on college campuses pose vexing socio-political problems, and the interventions to mitigate the effects require evaluating the pervasiveness of the phenomenon on campuses as well the impacts on students' psychological state. \\n\\nData and Methods. Given the growing use of social media among college students, we target the above issues by studying the online aspect of hateful speech in a dataset of 6 million Reddit comments shared in 174 college communities. To quantify the prevelence of hateful speech in an online college community, we devise College Hate Index (CHX). Next, we examine its distribution across the categories of hateful speech,behavior, class, disability, ethnicity, gender, physical appearance, race, religion, andsexual orientation. We then employ a causal-inference framework to study the psychological effects of hateful speech, particularly in the form of individuals' online stress expression. Finally, we characterize their psychological endurance to hateful speech by analyzing their language -- their discriminatory keyword use, and their personality traits. \\n\\nResults. We find that hateful speech is prevalent in college subreddits, and 25% of them show greater hateful speech than non-college subreddits. We also find that the exposure to hate leads to greater stress expression. However, everybody exposed is not equally affected; some show lower psychological endurance than others. Low endurance individuals are more vulnerable to emotional outbursts, and are more neurotic than those with higher endurance. \\n\\n Discussion. Our work bears implications for policy-making and intervention efforts to tackle the damaging effects of online hateful speech in colleges. From technological perspective, our work caters to mental health support provisions on college campuses, and to moderation efforts in online college communities. In addition, given the charged aspect of speech dilemma, we highlight the ethical implications of our work. Our work lays the foundation for studying the psychological impacts of hateful speech in online communities in general, and situated communities in particular (the ones that have both an offline and an online analog).\",\n \"Title: Introduction to this special issue on unifying human computer interaction and artificial intelligence\\nYear: 2020\\n\\nAbstract: McCarthy (1998) defined Artificial Intelligence (AI) as both “the science and engineering of intelligent machines, especially computer programs” and the “computational part of the ability to achieve goals in the world.” Today, AI is increasingly deployed across many domains of direct societal relevance, such as transportation, retail, criminal justice, finance, and health. But these very domains that AI is aiming to revolutionize may also be where human implications are the most momentous. The potential negative effects of AI on society, whether amplifying human biases or the perils of automation, cannot be ignored, and as a result, such topics are increasingly discussed in scholarly and popular press contexts. As the New York Times notes:“… if we want [AI] to play a positive role in tomorrow’s world, it must be guided by human concerns”(Li, 2018). The relationship between technology and humans is the direct focus of …\",\n \"Title: Social media derived biomarkers of mental health: opportunities, pitfalls, and the next frontier\\nYear: 2021\\n\\nAbstract: ABSTRACTSocial media data is being increasingly used to computationally learn about and infer behaviors and underlying psychologies of people. Adopting a social ecological perspective, this talk highlights a series of approaches that allow the gleaning of potentially useful mental health biomarkers by harnessing At the same time, the talk discusses a critical analytic study surrounding the pitfalls of social media biomarkers of mental health -- in particular, the theoretical, domain, and psychometric validity of this novel information source as well as its underlying biases, when appropriated to augment conventionally gathered biomarkers, such as those gathered via surveys and verbal self-reports. Then, to overcome these pitfalls, this talk presents results from a case study, where computational algorithms to glean mental health biomarkers from social media were developed in a context-sensitive and human-centered way, in collaboration with domain experts and stakeholders. Specifically, this study, a collaboration with a health provider, reveals the ability and implications of using social media data of consented schizophrenia patients to forecast relapse and support clinical decision-making. The talk concludes with provocations of the path forward, emphasizing the need for a collaborative, multidisciplinary research agenda while realizing the potential of social media derived biomarkers in mental health -- one that incorporates methodological rigor, ethics, and accountability, all at once.\",\n \"Title: Latent Hatred - A Benchmark for Understanding Implicit Hate Speech.\\nYear: 2021\\n\\nAbstract: Hate speech has grown significantly on social media, causing serious consequences for victims of all demographics. Despite much attention being paid to characterize and detect discriminatory speech, most work has focused on explicit or overt hate speech, failing to address a more pervasive form based on coded or indirect language. To fill this gap, this work introduces a theoretically-justified taxonomy of implicit hate speech and a benchmark corpus with fine-grained labels for each message and its implication. We present systematic analyses of our dataset using contemporary baselines to detect and explain implicit hate speech, and we discuss key features that challenge existing models. This dataset will continue to serve as a useful benchmark for understanding this multifaceted issue.\",\n \"Title: MOSafely: Building an Open-Source HCAI Community to Make the Internet a Safer Place for Youth\\nYear: 2021\\n\\nAbstract: ABSTRACTThe goal of this one-day workshop is to build an active community of researchers, practitioners, and policy-makers who are jointly committed to leveraging human-centered artificial intelligence (HCAI) to make the internet a safer place for youth. This community will be founded on the principles of open innovation and human dignity to address some of the most salient safety issues of modern-day internet, including online harassment, sexual solicitation, and the mental health of vulnerable internet users, particularly adolescents and young adults. We will partner with Mozilla Research Foundation to launch a new open project named “MOSafely.org,” which will serve as a platform for code library, research, and data contributions that support the mission of internet safety. During the workshop, we will discuss: 1) the types of contributions and technical standards needed to advance the state-of-the art in online risk detection, 2) the practical, legal, and ethical challenges that we will face, and 3) ways in which we can overcome these challenges through the use of HCAI to create a sustainable community. An end goal of creating the MOSafely community is to offer evidence-based, customizable, robust, and low-cost technologies that are accessible to the public for youth protection.\",\n \"Title: Assessing the mental health of college students by leveraging social media data\\nYear: 2021\\n\\nAbstract: AbstractThe mental health of college students is a growing concern and gauging the mental health needs of this group is difficult to assess in real-time and in scale. The ubiquity and widespread use of social media, particularly among young adults, provides opportunities for various stakeholders to proactively assess the mental health of college students and provide timely and tailored support.\",\n \"Title: Overcoming Language Disparity in Online Content Classification with Multimodal Learning\\nYear: 2022\\n\\nAbstract: Advances in Natural Language Processing (NLP) have revolutionized the way researchers and practitioners address crucial societal problems. Large language models are now the standard to develop state-of-the-art solutions for text detection and classification tasks. However, the development of advanced computational techniques and resources is disproportionately focused on the English language, sidelining a majority of the languages spoken globally. While existing research has developed better multilingual and monolingual language models to bridge this language disparity between English and non-English languages, we explore the promise of incorporating the information contained in images via multimodal machine learning. Our comparative analyses on three detection tasks focusing on crisis information, fake news, and emotion recognition, as well as five high-resource non-English languages, demonstrate that: (a) detection frameworks based on pre-trained large language models like BERT and multilingual-BERT systematically perform better on the English language compared against non-English languages, and (b) including images via multimodal learning bridges this performance gap. We situate our findings with respect to existing work on the pitfalls of large language models, and discuss their theoretical and practical implications. Resources for this paper are available at https://multimodality-language-disparity.github.io/.\",\n \"Title: How Is Vaping Framed on Online Knowledge Dissemination Platforms?\\nYear: 2022\\n\\nAbstract: Studying how vaping is framed on various knowledge dissemination platforms (e.g., Quora, Reddit, Wikipedia) is central to understanding the process of knowledge dissemination around vaping. Such understanding can help us craft tools specific to each platform, to dispel vaping misperceptions and reinforce evidence-based information. We analyze 1,888 articles and 1,119,453 vaping posts to study how vaping is framed across multiple knowledge dissemination platforms (Wikipedia, Quora, Medium, Reddit, Stack Exchange, wikiHow). We use NLP techniques to understand these differences. As an example, regarding question answering results, for the question What is vaping for?, we note answers framing vaping as a smoking cessation tool in Quora, Medium, and Stack Exchange. Reddit tended to frame vaping as a hobby. Wikipedia had a mix of answers, some centered on EVALI, and others on vaping as harm reduction. Broadly, results indicate that Quora is an appropriate venue for those looking to transition from smoking to vaping. Other platforms (Reddit, wikiHow) are more for vaping hobbyists and may not sufficiently dissuade youth vaping. Conversely, Wikipedia may exaggerate vaping harms, dissuading smokers from transitioning. A strength of our work is how the different techniques we have applied validate each other. Stakeholders may utilize our findings to design vaping regulation that clarifies the role of vapes as a smoking cessation tool.\",\n \"Title: Employing Social Media to Improve Mental Health: Pitfalls, Lessons Learned, and the Next Frontier\\nYear: 2022\\n\\nAbstract: ABSTRACT Social media data is being increasingly used to computationally learn about and infer the mental health states of individuals and populations. Despite being touted as a powerful means to shape interventions and impact mental health recovery, little do we understand about the theoretical, domain, and psychometric validity of this novel information source, or its underlying biases, when appropriated to augment conventionally gathered data, such as surveys and verbal self-reports. This talk presents a critical analytic perspective on the pitfalls of social media signals of mental health, especially when they are derived from “proxy” diagnostic indicators, often removed from the real-world context in which they are likely to be used. Then, to overcome these pitfalls, this talk presents results from two case studies, where machine learning algorithms to glean mental health insights from social media were developed in a context-sensitive and human-centered way, in collaboration with domain experts and stakeholders. The first of these case studies, a collaboration with a health provider, focuses on the individual-perspective, and reveals the ability and implications of using social media data of consented schizophrenia patients to forecast relapse and support clinical decision-making. Scaling up to populations, in collaboration with a federal organization and towards influencing public health policy, the second case study seeks to forecast nationwide rates of suicide fatalities using social media signals, in conjunction with health services data. The talk concludes with discussions of the path forward, emphasizing the need for a collaborative, multi-disciplinary research agenda while realizing the potential of social media data and machine learning in mental health – one that incorporates methodological rigor, ethics, and accountability, all at once.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":93,"string":"93"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13371,"string":"13,371"}}},{"rowIdx":13372,"cells":{"question_id":{"kind":"string","value":"Samuel Madden"},"question":{"kind":"string","value":"Generate an abstract for the title \"Guest Editors' Introduction: Distributed Data Mining--Framework and Implementations\" using the following items: 1. Data volumes\n2. Data mining\n3. Knowledge discovery\n4. Distributed data mining\n5. Complexity."},"answer":{"kind":"string","value":"It is now possible to gather and store incredible volumes of data, creating opportunities for large-scale data-driven knowledge discovery. Data mining technology has emerged as a means of performing this discovery, and the added dimension of distributed data mining increases this process'scomplexity."},"correct_answer":{"kind":"string","value":"It is now possible to gather and store incredible volumes of data, creating opportunities for large-scale data-driven knowledge discovery. Data mining technology has emerged as a means of performing this discovery, and the added dimension of distributed data mining increases this process'scomplexity."},"documents":{"kind":"list like","value":["Title: A continuous query system for dynamic route planning\nYear: 2011\n\nAbstract: In this paper, we address the problem of answering continuous route planning queries over a road network, in the presence of updates to the delay (cost) estimates of links. A simple approach to this problem would be to recompute the best path for all queries on arrival of every delay update. However, such a naive approach scales poorly when there are many users who have requested routes in the system. Instead, we propose two new classes of approximate techniques - K-paths and proximity measures to substantially speed up processing of the set of designated routes specified by continuous route planning queries in the face of incoming traffic delay updates. Our techniques work through a combination of pre-computation of likely good paths and by avoiding complete recalculations on every delay update, instead only sending the user new routes when delays change significantly. Based on an experimental evaluation with 7,000 drives from real taxi cabs, we found that the routes delivered by our techniques are within 5% of the best shortest path and have run times an order of magnitude or less compared to a naive approach.","Title: OLTP through the looking glass, and what we found there\nYear: 2008\n\nAbstract: Online Transaction Processing (OLTP) databases include a suite of features - disk-resident B-trees and heap files, locking-based concurrency control, support for multi-threading - that were optimized for computer technology of the late 1970's. Advances in modern processors, memories, and networks mean that today's computers are vastly different from those of 30 years ago, such that many OLTP databases will now fit in main memory, and most OLTP transactions can be processed in milliseconds or less. Yet database architecture has changed little. Based on this observation, we look at some interesting variants of conventional database systems that one might build that exploit recent hardware trends, and speculate on their performance through a detailed instruction-level breakdown of the major components involved in a transaction processing database system (Shore) running a subset of TPC-C. Rather than simply profiling Shore, we progressively modified it so that after every feature removal or optimization, we had a (faster) working system that fully ran our workload. Overall, we identify overheads and optimizations that explain a total difference of about a factor of 20x in raw performance. We also show that there is no single \"high pole in the tent\" in modern (memory resident) database systems, but that substantial time is spent in logging, latching, locking, B-tree, and buffer management operations.","Title: Adaptive Query Processing: Technology in Evolution\nYear: 2000\n\nAbstract: As query engines are scaled and federated, they must cope with highly unpredictable and changeable environments. In the Telegraph project, we are attempting to architect and implement a continuously adaptive query engine suitable for global-area systems, massive parallelism, and sensor networks. To set the stage for our research, we present a survey of prior work on adaptive query processing, focusing on three characterizations of adaptivity: the frequency of adaptivity, the effects of adaptivity, and the extent of adaptivity. Given this survey, we sketch directions for research in the Telegraph project.","Title: VTrack: accurate, energy-aware road traffic delay estimation using mobile phones\nYear: 2009\n\nAbstract: Traffic delays and congestion are a major source of inefficiency, wasted fuel, and commuter frustration. Measuring and localizing these delays, and routing users around them, is an important step towards reducing the time people spend stuck in traffic. As others have noted, the proliferation of commodity smartphones that can provide location estimates using a variety of sensors---GPS, WiFi, and/or cellular triangulation---opens up the attractive possibility of using position samples from drivers' phones to monitor traffic delays at a fine spatiotemporal granularity. This paper presents VTrack, a system for travel time estimation using this sensor data that addresses two key challenges: energy consumption and sensor unreliability. While GPS provides highly accurate location estimates, it has several limitations: some phones don't have GPS at all, the GPS sensor doesn't work in \"urban canyons\" (tall buildings and tunnels) or when the phone is inside a pocket, and the GPS on many phones is power-hungry and drains the battery quickly. In these cases, VTrack can use alternative, less energy-hungry but noisier sensors like WiFi to estimate both a user's trajectory and travel time along the route. VTrack uses a hidden Markov model (HMM)-based map matching scheme and travel time estimation method that interpolates sparse data to identify the most probable road segments driven by the user and to attribute travel times to those segments. We present experimental results from real drive data and WiFi access point sightings gathered from a deployment on several cars. We show that VTrack can tolerate significant noise and outages in these location estimates, and still successfully identify delay-prone segments, and provide accurate enough delays for delay-aware routing algorithms. We also study the best sampling strategies for WiFi and GPS sensors for different energy cost regimes.","Title: A measurement study of vehicular internet access using in situ Wi-Fi networks\nYear: 2006\n\nAbstract: The impressive penetration of 802.11-based wireless networks in many metropolitan areas around the world offers, for the first time, the opportunity of a \"grassroots\" wireless Internet service provided by users who \"open up\" their 802.11 (Wi-Fi) access points in a controlled manner to mobile clients. While there are many business, legal, and policy issues to be ironed out for this vision to become reality, we are concerned in this paper with an important technical question surrounding such a system: can such an unplanned network service provide reasonable performance to network clients moving in cars at vehicular speeds.To answer this question, we present the results of a measurement study carried out over 290 \"drive hours\" over a few cars under typical driving conditions, in and around the Boston metropolitan area (some of our data also comes from a car in Seattle). With a simple caching optimization to speed-up IP address acquisition, we find that for our driving patterns the median duration of link-layer connectivity at vehicular speeds is 13 seconds, the median connection upload bandwidth is 30 KBytes/s, and that the mean duration between successful associations to APs is 75 seconds. We also find that connections are equally probable across a range of urban speeds (up to 60 km/hour in our measurements). Our end-to-end TCP upload experiments had a median throughput of about 30 KBytes/s, which is consistent with typical uplink speeds of home broadband links in the US. The median TCP connection is capable of uploading about 216 KBytes of data.Our high-level conclusion is that grassroots Wi-Fi networks are viable for a variety of applications, particularly ones that can tolerate intermittent connectivity. We discuss how our measurement results can improve transport protocols in such networks.","Title: Counting with the crowd\nYear: 2012\n\nAbstract: In this paper, we address the problem of selectivity estimation in a crowdsourced database. Specifically, we develop several techniques for using workers on a crowdsourcing platform like Amazon's Mechanical Turk to estimate the fraction of items in a dataset (e.g., a collection of photos) that satisfy some property or predicate (e.g., photos of trees). We do this without explicitly iterating through every item in the dataset. This is important in crowd-sourced query optimization to support predicate ordering and in query evaluation, when performing a GROUP BY operation with a COUNT or AVG aggregate. We compare sampling item labels, a traditional approach, to showing workers a collection of items and asking them to estimate how many satisfy some predicate. Additionally, we develop techniques to eliminate spammers and colluding attackers trying to skew selectivity estimates when using this count estimation approach. We find that for images, counting can be much more effective than sampled labeling, reducing the amount of work necessary to arrive at an estimate that is within 1% of the true fraction by up to an order of magnitude, with lower worker latency. We also find that sampled labeling outperforms count estimation on a text processing task, presumably because people are better at quickly processing large batches of images than they are at reading strings of text. Our spammer detection technique, which is applicable to both the label- and count-based approaches, can improve accuracy by up to two orders of magnitude.","Title: Mobiscopes for Human Spaces\nYear: 2007\n\nAbstract: The proliferation of affordable mobile devices with processing and sensing capabilities, together with the rapid growth inubiquitous network connectivity, herald an era of mobiscopes: networked sensing applications that rely on multiple mobile sensors to accomplish global tasks. These distributed sensing systems extend the traditional sensor network model, introducing challenges in data management, data integrity, privacy, and network system design. Although several existing applications fit this description, they providetailored one-time solutions to what essentially is the same set of problems. It's time to work toward a general architecture thatidentifies common challenges and provides a general methodology for the design of future mobiscopes. Toward that end, this articlesurveys a variety of current and emerging mobile, networked, sensing applications; articulates their common challenges; and providesarchitectural guidelines and design directions for this important category of emerging distributed sensing systems. This article is partof a special issue on Building a Sensor-Rich World.","Title: Cabernet: vehicular content delivery using WiFi\nYear: 2008\n\nAbstract: Cabernet is a system for delivering data to and from moving vehicles using open 802.11 (WiFi) access points encountered opportunistically during travel. Using open WiFi access from the road can be challenging. Network connectivity in Cabernet is both fleeting (access points are typically within range for a few seconds) and intermittent (because the access points do not provide continuous coverage), and suffers from high packet loss rates over the wireless channel. On the positive side, WiFi data transfers, when available, can occur at broadband speeds. In this paper, we introduce two new components for improving openWiFi data delivery to moving vehicles: The first, QuickWiFi, is a streamlined client-side process to establish end-to-end connectivity, reducing mean connection time to less than 400 ms, from over 10 seconds when using standard wireless networking software. The second part, CTP, is a transport protocol that distinguishes congestion on the wired portion of the path from losses over the wireless link, resulting in a 2x throughput improvement over TCP. To characterize the amount of open WiFi capacity available to vehicular users, we deployed Cabernet on a fleet of 10 taxis in the Boston area. The long-term average transfer rate achieved was approximately 38 Mbytes/hour per car (86 kbit/s), making Cabernet a viable system for a number of non-interactive applications.","Title: Workload-aware database monitoring and consolidation\nYear: 2011\n\nAbstract: In most enterprises, databases are deployed on dedicated database servers. Often, these servers are underutilized much of the time. For example, in traces from almost 200 production servers from different organizations, we see an average CPU utilization of less than 4%. This unused capacity can be potentially harnessed to consolidate multiple databases on fewer machines, reducing hardware and operational costs. Virtual machine (VM) technology is one popular way to approach this problem. However, as we demonstrate in this paper, VMs fail to adequately support database consolidation, because databases place a unique and challenging set of demands on hardware resources, which are not well-suited to the assumptions made by VM-based consolidation. Instead, our system for database consolidation, named Kairos, uses novel techniques to measure the hardware requirements of database workloads, as well as models to predict the combined resource utilization of those workloads. We formalize the consolidation problem as a non-linear optimization program, aiming to minimize the number of servers and balance load, while achieving near-zero performance degradation. We compare Kairos against virtual machines, showing up to a factor of 12× higher throughput on a TPC-C-like benchmark. We also tested the effectiveness of our approach on real-world data collected from production servers at Wikia.com, Wikipedia, Second Life, and MIT CSAIL, showing absolute consolidation ratios ranging between 5.5:1 and 17:1.","Title: Fault-tolerance in the Borealis distributed stream processing system\nYear: 2008\n\nAbstract: We present a replication-based approach to fault-tolerant distributed stream processing in the face of node failures, network failures, and network partitions. Our approach aims to reduce the degree of inconsistency in the system while guaranteeing that available inputs capable of being processed are processed within a specified time threshold. This threshold allows a user to trade availability for consistency: a larger time threshold decreases availability but limits inconsistency, while a smaller threshold increases availability but produces more inconsistent results based on partial data. In addition, when failures heal, our scheme corrects previously produced results, ensuring eventual consistency.Our scheme uses a data-serializing operator to ensure that all replicas process data in the same order, and thus remain consistent in the absence of failures. To regain consistency after a failure heals, we experimentally compare approaches based on checkpoint/redo and undo/redo techniques and illustrate the performance trade-offs between these schemes.","Title: Active Learning for Crowd-Sourced Databases\nYear: 2012\n\nAbstract: Crowd-sourcing has become a popular means of acquiring labeled data for a wide variety of tasks where humans are more accurate than computers, e.g., labeling images, matching objects, or analyzing sentiment. However, relying solely on the crowd is often impractical even for data sets with thousands of items, due to time and cost constraints of acquiring human input (which cost pennies and minutes per label). In this paper, we propose algorithms for integrating machine learning into crowd-sourced databases, with the goal of allowing crowd-sourcing applications to scale, i.e., to handle larger datasets at lower costs. The key observation is that, in many of the above tasks, humans and machine learning algorithms can be complementary, as humans are often more accurate but slow and expensive, while algorithms are usually less accurate, but faster and cheaper. Based on this observation, we present two new active learning algorithms to combine humans and algorithms together in a crowd-sourced database. Our algorithms are based on the theory of non-parametric bootstrap, which makes our results applicable to a broad class of machine learning models. Our results, on three real-life datasets collected with Amazon's Mechanical Turk, and on 15 well-known UCI data sets, show that our methods on average ask humans to label one to two orders of magnitude fewer items to achieve the same accuracy as a baseline that labels random images, and two to eight times fewer questions than previous active learning schemes.","Title: Partial replay of long-running applications\nYear: 2011\n\nAbstract: Bugs in deployed software can be extremely difficult to track down. Invasive logging techniques, such as logging all non-deterministic inputs, can incur substantial runtime overheads. This paper shows how symbolic analysis can be used to re-create path equivalent executions for very long running programs such as databases and web servers. The goal is to help developers debug such long-running programs by allowing them to walk through an execution of the last few requests or transactions leading up to an error. The challenge is to provide this functionality without the high runtime overheads associated with traditional replay techniques based on input logging or memory snapshots. Our approach achieves this by recording a small amount of information about program execution, such as the direction of branches taken, and then using symbolic analysis to reconstruct the execution of the last few inputs processed by the application, as well as the state of memory before these inputs were executed. We implemented our technique in a new tool called bbr. In this paper, we show that it can be used to replay bugs in long-running single-threaded programs starting from the middle of an execution. We show that bbr incurs low recording overhead (avg. of 10%) during program execution, which is much less than existing replay schemes. We also show that it can reproduce real bugs from web servers, database systems, and other common utilities.","Title: Information Survival Threshold In Sensor And P2p Networks\nYear: 2007\n\nAbstract: Consider a network of, say, sensors, or P2P nodes, or bluetooth-enabled cell-phones, where nodes transmit information to each other and where links and nodes can go up or down. Consider also a 'datum', that is, a piece of information, like a report of an emergency condition in a sensor network, a national traditional song, or a mobile phone virus. How often should nodes transmit the datum to each other, so that the datum can survive (or, in the virus case, under what conditions will the virus die out)? Clearly, the link and node fault probabilities are important - what else is needed to ascertain the survivability of the datum? We propose and solve the problem using non-linear dynamical systems and fixed point stability theorems. We provide a closed-form formula that, surprisingly, depends on only one additional parameter, the largest eigenvalue of the connectivity matrix. We illustrate the accuracy of our analysis on realistic and real settings, like mote sensor networks from Intel and MIT, as well as Gnutella and P2P networks.","Title: A demonstration of DBWipes: clean as you query\nYear: 2012\n\nAbstract: As data analytics becomes mainstream, and the complexity of the underlying data and computation grows, it will be increasingly important to provide tools that help analysts understand the underlying reasons when they encounter errors in the result. While data provenance has been a large step in providing tools to help debug complex workflows, its current form has limited utility when debugging aggregation operators that compute a single output from a large collection of inputs. Traditional provenance will return the entire input collection, which has very low precision. In contrast, users are seeking precise descriptions of the inputs that caused the errors. We propose a Ranked Provenance System, which identifies subsets of inputs that influenced the output error, describes each subset with human readable predicates and orders them by contribution to the error. In this demonstration, we will present DBWipes, a novel data cleaning system that allows users to execute aggregate queries, and interactively detect, understand, and clean errors in the query results. Conference attendees will explore anomalies in campaign donations from the current US presidential election and in readings from a 54-node sensor deployment.","Title: Processing and visualizing the data in tweets\nYear: 2011\n\nAbstract: Microblogs such as Twitter provide a valuable stream of diverse user-generated data. While the data extracted from Twitter is generally timely and accurate, the process by which developers extract structured data from the tweet stream is ad-hoc and requires reimplementation of common data manipulation primitives. In this paper, we present two systems for querying and extracting structure from Twitter-embedded data. The first, TweeQL, provides a streaming SQL-like interface to the Twitter API, making common tweet processing tasks simpler. The second, TwitInfo, shows how end-users can interact with and understand aggregated data from the tweet stream, in addition to showcasing the power of the TweeQL language. Together these systems show the richness of content that can be extracted from Twitter.","Title: Partitioning techniques for fine-grained indexing\nYear: 2011\n\nAbstract: Many data-intensive websites use databases that grow much faster than the rate that users access the data. Such growing datasets lead to ever-increasing space and performance overheads for maintaining and accessing indexes. Furthermore, there is often considerable skew with popular users and recent data accessed much more frequently. These observations led us to design Shinobi, a system which uses horizontal partitioning as a mechanism for improving query performance to cluster the physical data, and increasing insert performance by only indexing data that is frequently accessed. We present database design algorithms that optimally partition tables, drop indexes from partitions that are infrequently queried, and maintain these partitions as workloads change. We show a 60脳 performance improvement over traditionally indexed tables using a real-world query workload derived from a traffic monitoring application","Title: Performance tradeoffs in read-optimized databases\nYear: 2006\n\nAbstract: Database systems have traditionally optimized performance for write-intensive workloads. Recently, there has been renewed interest in architectures that optimize read performance by using column-oriented data representation and light-weight compression. This previous work has shown that under certain broad classes of workloads, column-based systems can outperform row-based systems. Previous work, however, has not characterized the precise conditions under which a particular query workload can be expected to perform better on a column-oriented database.In this paper we first identify the distinctive components of a read-optimized DBMS and describe our implementation of a high-performance query engine that can operate on both row and column-oriented data. We then use our prototype to perform an in-depth analysis of the tradeoffs between column and row-oriented architectures. We explore these tradeoffs in terms of disk bandwidth, CPU cache latency, and CPU cycles. We show that for most database workloads, a carefully designed column system can outperform a carefully designed row system, sometimes by an order of magnitude. We also present an analytical model to predict whether a given workload on a particular hardware configuration is likely to perform better on a row or column-based system.","Title: Twitinfo: aggregating and visualizing microblogs for event exploration\nYear: 2011\n\nAbstract: Microblogs are a tremendous repository of user-generated content about world events. However, for people trying to understand events by querying services like Twitter, a chronological log of posts makes it very difficult to get a detailed understanding of an event. In this paper, we present TwitInfo, a system for visualizing and summarizing events on Twitter. TwitInfo allows users to browse a large collection of tweets using a timeline-based display that highlights peaks of high tweet activity. A novel streaming algorithm automatically discovers these peaks and labels them meaningfully using text from the tweets. Users can drill down to subevents, and explore further via geolocation, sentiment, and popular URLs. We contribute a recall-normalized aggregate sentiment visualization to produce more honest sentiment overviews. An evaluation of the system revealed that users were able to reconstruct meaningful summaries of events in a small amount of time. An interview with a Pulitzer Prize-winning journalist suggested that the system would be especially useful for understanding a long-running event and for identifying eyewitnesses. Quantitatively, our system can identify 80-100% of manually labeled peaks, facilitating a relatively complete view of each event studied.","Title: Exploiting Correlated Attributes in Acquisitional Query Processing\nYear: 2005\n\nAbstract: Sensor networks and other distributed information systems (such as the Web) must frequently access data that has a high per-attribute acquisition cost, in terms of energy, latency, or computational resources. When executing queries that contain several predicates over such expensive attributes, we observe that it can be beneficial to use correlations to automatically introduce low-cost attributes whose observation will allow the query processor to better estimate the selectivity of these expensive predicates. In particular, we show how to build conditional plans that branch into one or more sub-plans, each with a different ordering for the expensive query predicates, based on the runtime observation of low-cost attributes. We frame the problem of constructing the optimal conditional plan for a given user query and set of candidate low-cost attributes as an optimization problem. We describe an exponential time algorithm for finding such optimal plans, and describe a polynomial-time heuristic for identifying conditional plans that perform well in practice. We also show how to compactly model conditional probability distributions needed to identify correlations and build these plans. We evaluate our algorithms against several real-world sensor-network data sets, showing several-times performance increases for a variety of queries versus traditional optimization techniques.","Title: ZStream: a cost-based query processor for adaptively detecting composite events\nYear: 2009\n\nAbstract: Composite (or Complex) event processing (CEP) systems search sequences of incoming events for occurrences of user-specified event patterns. Recently, they have gained more attention in a variety of areas due to their powerful and expressive query language and performance potential. Sequentiality (temporal ordering) is the primary way in which CEP systems relate events to each other. In this paper, we present a CEP system called ZStream to efficiently process such sequential patterns. Besides simple sequential patterns, ZStream is also able to detect other patterns, including conjunction, disjunction, negation and Kleene closure. Unlike most recently proposed CEP systems, which use non-deterministic finite automata (NFA's) to detect patterns, ZStream uses tree-based query plans for both the logical and physical representation of query patterns. By carefully designing the underlying infrastructure and algorithms, ZStream is able to unify the evaluation of sequence, conjunction, disjunction, negation, and Kleene closure as variants of the join operator. Under this framework, a single pattern in ZStream may have several equivalent physical tree plans, with different evaluation costs. We propose a cost model to estimate the computation costs of a plan. We show that our cost model can accurately capture the actual runtime behavior of a plan, and that choosing the optimal plan can result in a factor of four or more speedup versus an NFA based approach. Based on this cost model and using a simple set of statistics about operator selectivity and data rates, ZStream is able to adaptively and seamlessly adjust the order in which it detects patterns on the fly. Finally, we describe a dynamic programming algorithm used in our cost model to efficiently search for an optimal query plan for a given pattern.","Title: Mesh Networking Research and Technology for Multihop Wireless Networks\nYear: 2008\n\nAbstract: Mesh networking encompasses a broad class of wireless networks in which nodes collaboratively route packets. All mesh networks' benefits, such as lower costs, scalability, and easy installation, introduce new challenges that we must address.","Title: Synthesizing entity matching rules by examples\nYear: 2017\n\nAbstract: AbstractEntity matching (EM) is a critical part of data integration. We study how to synthesize entity matching rules from positive-negative matching examples. The core of our solution is program synthesis, a powerful tool to automatically generate rules (or programs) that satisfy a given high-level specification, via a predefined grammar. This grammar describes a General Boolean Formula (GBF) that can include arbitrary attribute matching predicates combined by conjunctions (∧), disjunctions (∨) and negations (¬), and is expressive enough to model EM problems, from capturing arbitrary attribute combinations to handling missing attribute values. The rules in the form of GBF are more concise than traditional EM rules represented in Disjunctive Normal Form (DNF). Consequently, they are more interpretable than decision trees and other machine learning algorithms that output deep trees with many branches. We present a new synthesis algorithm that, given only positive-negative examples as input, synthesizes EM rules that are effective over the entire dataset. Extensive experiments show that we outperform other interpretable rules (e.g., decision trees with low depth) in effectiveness, and are comparable with non-interpretable tools (e.g., decision trees with high depth, gradient-boosting trees, random forests and SVM).","Title: \"Extra-sensory perception\" for wireless networks\nYear: 2010\n\nAbstract: Commodity smartphones and tablet devices now come equipped with a variety of sensors, including accelerometers, multiple positioning sensors, magnetic compasses, and inertial sensors (gyros). In this paper, we posit that these sensors can be profitably used to improve the performance of wireless network protocols running on these mobile devices, and introduce the idea of using external sensor hints for this purpose. We focus on mobility hints, including the device's state of motion, speed, direction of movement, and position. We outline how these hints can be used to: increase throughput by adapting bit rate selection to the state of movement; reduce the bandwidth required for estimating link delivery probabilities; improve the connectivity of routes in vehicular mesh networks using directionality hints; and enable access points to tailor the management of clients to their mobility.","Title: The emergence of a networking primitive in wireless sensor networks\nYear: 2008\n\nAbstract: The wireless sensor network community approached networking abstractions as an open question, allowing answers to emerge with time and experience. The Trickle algorithm has become a basic mechanism used in numerous protocols and systems. Trickle brings nodes to eventual consistency quickly and efficiently while remaining remarkably robust to variations in network density, topology, and dynamics. Instead of flooding a network with packets, Trickle uses a \"polite gossip\" policy to control send rates so each node hears just enough packets to stay consistent. This simple mechanism enables Trickle to scale to 1000-fold changes in network density, reach consistency in seconds, and require only a few bytes of state yet impose a maintenance cost of a few sends an hour. Originally designed for disseminating new code, experience has shown Trickle to have much broader applicability, including route maintenance and neighbor discovery. This paper provides an overview of the research challenges wireless sensor networks face, describes the Trickle algorithm, and outlines several ways it is used today.","Title: The design of an acquisitional query processor for sensor networks\nYear: 2003\n\nAbstract: We discuss the design of an acquisitional query processor for data collection in sensor networks. Acquisitional issues are those that pertain to where, when, and how often data is physically acquired (sampled) and delivered to query processing operators. By focusing on the locations and costs of acquiring data, we are able to significantly reduce power consumption over traditional passive systems that assume the a priori existence of data. We discuss simple extensions to SQL for controlling data acquisition, and show how acquisitional issues influence query optimization, dissemination, and execution. We evaluate these issues in the context of TinyDB, a distributed query processor for smart sensor devices, and show how acquisitional techniques can provide significant reductions in power consumption on our sensor devices.","Title: Querying continuous functions in a database system\nYear: 2008\n\nAbstract: Many scientific, financial, data mining and sensor network applications need to work with continuous, rather than discrete data e.g., temperature as a function of location, or stock prices or vehicle trajectories as a function of time. Querying raw or discrete data is unsatisfactory for these applications -- e.g., in a sensor network, it is necessary to interpolate sensor readings to predict values at locations where sensors are not deployed. In other situations, raw data can be inaccurate owing to measurement errors, and it is useful to fit continuous functions to raw data and query the functions, rather than raw data itself -- e.g., fitting a smooth curve to noisy sensor readings, or a smooth trajectory to GPS data containing gaps or outliers. Existing databases do not support storing or querying continuous functions, short of brute-force discretization of functions into a collection of tuples. We present FunctionDB, a novel database system that treats mathematical functions as first-class citizens that can be queried like traditional relations. The key contribution of FunctionDB is an efficient and accurate algebraic query processor - for the broad class of multi-variable polynomial functions, FunctionDB executes queries directly on the algebraic representation of functions without materializing them into discrete points, using symbolic operations: zero finding, variable substitution, and integration. Even when closed form solutions are intractable, FunctionDB leverages symbolic approximation operations to improve performance. We evaluate FunctionDB on real data sets from a temperature sensor network, and on traffic traces from Boston roads. We show that operating in the functional domain has substantial advantages in terms of accuracy (15-30%) and up to order of magnitude (10x-100x) performance wins over existing approaches that represent models as discrete collections of points.","Title: CORADD: correlation aware database designer for materialized views and indexes\nYear: 2010\n\nAbstract: We describe an automatic database design tool that exploits correlations between attributes when recommending materialized views (MVs) and indexes. Although there is a substantial body of related work exploring how to select an appropriate set of MVs and indexes for a given workload, none of this work has explored the effect of correlated attributes (e.g., attributes encoding related geographic information) on designs. Our tool identifies a set of MVs and secondary indexes such that correlations between the clustered attributes of the MVs and the secondary indexes are enhanced, which can dramatically improve query performance. It uses a form of Integer Linear Programming (ILP) called ILP Feedback to pick the best set of MVs and indexes for given database size constraints. We compare our tool with a state-of-the-art commercial database designer on two workloads, APB-1 and SSB (Star Schema Benchmark---similar to TPC-H). Our results show that a correlation-aware database designer can improve query performance up to 6 times within the same space budget when compared to a commercial database designer.","Title: Distributed regression: an efficient framework for modeling sensor network data\nYear: 2004\n\nAbstract: We present distributed regression, an efficient and general framework for in-network modeling of sensor data. In this framework, the nodes of the sensor network collaborate to optimally fit a global function to each of their local measurements. The algorithm is based upon kernel linear regression, where the model takes the form of a weighted sum of local basis functions; this provides an expressive yet tractable class of models for sensor network data. Rather than transmitting data to one another or outside the network, nodes communicate constraints on the model parameters, drastically reducing the communication required. After the algorithm is run, each node can answer queries for its local region, or the nodes can efficiently transmit the parameters of the model to a user outside the network. We present an evaluation of the algorithm based upon data from a 48-node sensor network deployment at the Intel Research - Berkeley Lab, demonstrating that our distributed algorithm converges to the optimal solution at a fast rate and is very robust to packet losses.","Title: Tweets as data: demonstration of TweeQL and Twitinfo\nYear: 2011\n\nAbstract: Microblogs such as Twitter are a tremendous repository of user-generated content. Increasingly, we see tweets used as data sources for novel applications such as disaster mapping, brand sentiment analysis, and real-time visualizations. In each scenario, the workflow for processing tweets is ad-hoc, and a lot of unnecessary work goes into repeating common data processing patterns. We introduce TweeQL, a stream query processing language that presents a SQL-like query interface for unstructured tweets to generate structured data for downstream applications. We have built several tools on top of TweeQL, most notably TwitInfo, an event timeline generation and exploration interface that summarizes events as they are discussed on Twitter. Our demonstration will allow the audience to interact with both TweeQL and TwitInfo to convey the value of data embedded in tweets.","Title: C-Store: A Column-oriented DBMS\nYear: 2005\n\nAbstract: This paper presents the design of a read-optimized relational DBMS that contrasts sharply with most current systems, which are write-optimized. Among the many differences in its design are: storage of data by column rather than by row, careful coding and packing of objects into storage including main memory during query processing, storing an overlapping collection of column-oriented projections, rather than the current fare of tables and indexes, a non-traditional implementation of transactions which includes high availability and snapshot isolation for read-only transactions, and the extensive use of bitmap indexes to complement B-tree structures.We present preliminary performance data on a subset of TPC-H and show that the system we are building, C-Store, is substantially faster than popular commercial products. Hence, the architecture looks very encouraging.","Title: An Integration Framework for Sensor Networks and Data Stream Management Systems\nYear: 2004\n\nAbstract: This demonstration shows an integrated query processing environment where users can seam- lessly query both a data stream management system and a sensor network with one query expression. By integrating the two query pro- cessing systems, the optimization goals of the sensor network (primarily power) and server network (primarily latency and quality) can be unifled into one quality of service metric. The demo shows various steps of the unifled optimization process for a sample query where the efiects of each step that the optimizer takes can be directly viewed using a quality of service monitor. Our demo includes sensors deployed in the demo area in a tiny mockup of a factory application.","Title: Sync kit: a persistent client-side database caching toolkit for data intensive websites\nYear: 2010\n\nAbstract: We introduce a client-server toolkit called Sync Kit that demonstrates how client-side database storage can improve the performance of data intensive websites. Sync Kit is designed to make use of the embedded relational database defined in the upcoming HTML5 standard to offload some data storage and processing from a web server onto the web browsers to which it serves content. Our toolkit provides various strategies for synchronizing relational database tables between the browser and the web server, along with a client-side template library so that portions web applications may be executed client-side. Unlike prior work in this area, Sync Kit persists both templates and data in the browser across web sessions, increasing the number of concurrent connections a server can handle by up to a factor of four versus that of a traditional server-only web stack and a factor of three versus a recent template caching approach.","Title: Mobius: unified messaging and data serving for mobile apps\nYear: 2012\n\nAbstract: Mobile application development is challenging for several reasons: intermittent and limited network connectivity, tight power constraints, server-side scalability concerns, and a number of fault-tolerance issues. Developers handcraft complex solutions that include client-side caching, conflict resolution, disconnection tolerance, and backend database sharding. To simplify mobile app development, we present Mobius, a system that addresses the messaging and data management challenges of mobile application development. Mobius introduces MUD (Messaging Unified with Data). MUD presents the programming abstraction of a logical table of data that spans devices and clouds. Applications using Mobius can asynchronously read from/write to MUD tables, and also receive notifications when tables change via continuous queries on the tables. The system combines dynamic client-side caching (with intelligent policies chosen on the server-side, based on usage patterns across multiple applications), notification services, flexible query processing, and a scalable and highly available cloud storage system. We present an initial prototype to demonstrate the feasibility of our design. Even in our initial prototype, remote read and write latency overhead is less than 52% when compared to a hand-tuned solution. Our dynamic caching reduces the number of messages by a factor of 4 to 8.5 when compared to fixed strategies, thus reducing latency, bandwidth, power, and server load costs, while also reducing data staleness.","Title: Mobile applications need targeted micro-updates\nYear: 2013\n\nAbstract: Smart-phone applications (\"apps\") run across a wide range of environmental conditions, locations, and hardware platforms. They are often subject to an array of interactions that are hard or impossible for developers to emulate or even anticipate during testing. Once an application is released, feedback obtained from users and from analytics over usage and performance data result in further modifications. Many of these changes are relatively small, and can often be parameterized.","Title: Resource-Aware Wireless Sensor-Actuator Networks\nYear: 2005\n\nAbstract: Innovations in wireless sensor networks (WSNs) have dramatically expanded the applicability of control technol- ogy in day-to-day life, by enabling the cost-effective deployment of large scale sensor-actuator systems. In this paper, we discuss the issues and challenges involved in deploying control-oriented applications over unreliable, resource-constrainedWSNs, and describe the design of our planned Sensor Control System (SCS) that can enable the rapid development and deployment of such applications.","Title: Impact of double-blind reviewing on SIGMOD publication rates\nYear: 2006\n\nAbstract: Starting with the 2001 SIGMOD conference, the SIGMOD Chair, in consultation with the SIGMOD Advisory Committee, imposed a double blind rule on all future SIGMOD conferences. While there are many reasons why double-blind reviewing might be a good idea, the one most frequently cited is that it is fairer to more junior researchers. It is not, however, without its problems, including anecdotal reports of papers being rejected because their authors failed to cite their own papers as related work in order to not violate the anonymity rules and a complication of the job of the program chair who must interpret and enforce the double-blind rules. One very qualified individual turned down an offer to be PC chair of an upcoming SIGMOD conference because he did not want to have to deal with the headaches of double-blind reviewing.","Title: An energy-efficient querying framework in sensor networks for detecting node similarities\nYear: 2006\n\nAbstract: We propose an energy-efficient framework, called SAF, for approximate querying and clustering of nodes in a sensor network. SAF uses simple time series forecasting models to predict sensor readings. The idea is to build these local models at each node, transmit them to the root of the network (the \"sink\"), and use them to approximately answer user queries. Our approach dramatically reduces communication relative to previous approaches for querying sensor networks by exploiting properties of these local models, since each sensor communicates with the sink only when its local model varies due to changes in the underlying data distribution. In our experimental results performed on a trace of real data, we observed on average about 150 message transmissions from each sensor over a week (including the learning phase) to correctly predict temperatures to within +/- 0.5°C.SAF also provides a mechanism to detect data similarities between nodes and organize nodes into clusters at the sink at no additional communication cost. This is again achieved by exploiting properties of our local time series models, and by means of a novel definition of data similarity between nodes that is based not on raw data but on the prediction values. Our clustering algorithm is both very efficient and provably optimal in the number of clusters. Our clusters have several interesting features: first, they can capture similarity between far away nodes that are not geographically adjacent; second, cluster membership to variations in sensors' local models; third, nodes within a cluster are not required to track the membership of other nodes in the cluster. We present a number of simulation-based experimental results that demonstrate these properties of SAF.","Title: Task: Sensor Network In A Box\nYear: 2005\n\nAbstract: Sensornet systems research is being conducted with various applications and deployment scenarios in mind. In many of these scenarios, the presumption is that the sensornet will be deployed and managed by users who do not have a background in computer science. In this paper we describe the \"Tiny Application Sensor Kit (TASK), a system we have designed for use by end-users with minimal sensornet sophistication. We describe the requirements that guided our design, the architecture of the system, and results from initial deployments. Based on our experience to date we present preliminary design principles and research challenges that arise in delivering sensornet research to end users.","Title: UPI: a primary index for uncertain databases\nYear: 2010\n\nAbstract: Uncertain data management has received growing attention from industry and academia. Many efforts have been made to optimize uncertain databases, including the development of special index data structures. However, none of these efforts have explored primary (clustered) indexes for uncertain databases, despite the fact that clustering has the potential to offer substantial speedups for non-selective analytic queries on large uncertain databases. In this paper, we propose a new index called a UPI (Uncertain Primary Index) that clusters heap files according to uncertain attributes with both discrete and continuous uncertainty distributions. Because uncertain attributes may have several possible values, a UPI on an uncertain attribute duplicates tuple data once for each possible value. To prevent the size of the UPI from becoming unmanageable, its size is kept small by placing low-probability tuples in a special Cutoff Index that is consulted only when queries for low-probability values are run. We also propose several other optimizations, including techniques to improve secondary index performance and techniques to reduce maintenance costs and fragmentation by buffering changes to the table and writing updates in sequential batches. Finally, we develop cost models for UPIs to estimate query performance in various settings to help automatically select tuning parameters of a UPI. We have implemented a prototype UPI and experimented on two real datasets. Our results show that UPIs can significantly (up to two orders of magnitude) improve the performance of uncertain queries both over clustered and unclustered attributes. We also show that our buffering techniques mitigate table fragmentation and keep the maintenance cost as low as or even lower than using an unclustered heap file.","Title: MauveDB: supporting model-based user views in database systems\nYear: 2006\n\nAbstract: Real-world data --- especially when generated by distributed measurement infrastructures such as sensor networks --- tends to be incomplete, imprecise, and erroneous, making it impossible to present it to users or feed it directly into applications. The traditional approach to dealing with this problem is to first process the data using statistical or probabilistic models that can provide more robust interpretations of the data. Current database systems, however, do not provide adequate support for applying models to such data, especially when those models need to be frequently updated as new data arrives in the system. Hence, most scientists and engineers who depend on models for managing their data do not use database systems for archival or querying at all; at best, databases serve as a persistent raw data store.In this paper we define a new abstraction called model-based views and present the architecture of MauveDB, the system we are building to support such views. Just as traditional database views provide logical data independence, model-based views provide independence from the details of the underlying data generating mechanism and hide the irregularities of the data by using models to present a consistent view to the users. MauveDB supports a declarative language for defining model-based views, allows declarative querying over such views using SQL, and supports several different materialization strategies and techniques to efficiently maintain them in the face of frequent updates. We have implemented a prototype system that currently supports views based on regression and interpolation, using the Apache Derby open source DBMS, and we present results that show the utility and performance benefits that can be obtained by supporting several different types of model-based views in a database system.","Title: Model-Driven Data Acquisition in Sensor Networks\nYear: 2004\n\nAbstract: Declarative queries are proving to be an attractive paradigm for in- teracting with networks of wireless sensors. The metaphor that \"the sensornet is a database\" is problematic, however, because sensors do not exhaustively represent the data in the real world. In order to map the raw sensor readings onto physical reality, a model of that reality is required to complement the readings. In this paper, we enrich interactive sensor querying with statistical modeling tech- niques. We demonstrate that such models can help provide answers that are both more meaningful, and, by introducing approximations with probabilistic confidences, significantly more efficient to com- pute in both time and energy. Utilizing the combination of a model and live data acquisition raises the challenging optimization prob- lem of selecting the best sensor readings to acquire, balancing the increase in the confidence of our answer against the communication and data acquisition costs in the network. We describe an expo- nential time algorithm for finding the optimal solution to this op- timization problem, and a polynomial-time heuristic for identifying solutions that perform well in practice. We evaluate our approach on several real-world sensor-network data sets, taking into account the real measured data and communication quality, demonstrating that our model-based approach provides a high-fidelity representation of the real phenomena and leads to significant performance gains ver- sus traditional data acquisition techniques.","Title: Performance and resource modeling in highly-concurrent OLTP workloads\nYear: 2013\n\nAbstract: Database administrators of Online Transaction Processing (OLTP) systems constantly face difficult questions. For example, \"What is the maximum throughput I can sustain with my current hardware?\", \"How much disk I/O will my system perform if the requests per second double?\", or \"What will happen if the ratio of transactions in my system changes?\". Resource prediction and performance analysis are both vital and difficult in this setting. Here the challenge is due to high degrees of concurrency, competition for resources, and complex interactions between transactions, all of which non-linearly impact performance. Although difficult, such analysis is a key component in enabling database administrators to understand which queries are eating up the resources, and how their system would scale under load. In this paper, we introduce our framework, called DBSeer, that addresses this problem by employing statistical models that provide resource and performance analysis and prediction for highly concurrent OLTP workloads. Our models are built on a small amount of training data from standard log information collected during normal system operation. These models are capable of accurately measuring several performance metrics, including resource consumption on a per-transaction-type basis, resource bottlenecks, and throughput at different load levels. We have validated these models on MySQL/Linux with numerous experiments on standard benchmarks (TPC-C) and real workloads (Wikipedia), observing high accuracy (within a few percent error) when predicting all of the above metrics.","Title: Efficient Versioning for Scientific Array Databases\nYear: 2012\n\nAbstract: In this paper, we describe a versioned database storage manager we are developing for the SciDB scientific database. The system is designed to efficiently store and retrieve array-oriented data, exposing a ``no-overwrite'' storage model in which each update creates a new ``version'' of an array. This makes it possible to perform comparisons of versions produced at different times or by different algorithms, and to create complex chains and trees of versions. We present algorithms to efficiently encode these versions, minimizing storage space while still providing efficient access to the data. Additionally, we present an optimal algorithm that, given a long sequence of versions, determines which versions to encode in terms of each other (using delta compression) to minimize total storage space or query execution cost. We compare the performance of these algorithms on real world data sets from the National Oceanic and Atmospheric Administration (NOAA), Open Street Maps, and several other sources. We show that our algorithms provide better performance than existing version control systems not optimized for array data, both in terms of storage size and access time, and that our delta-compression algorithms are able to substantially reduce the total storage space when versions exist with a high degree of similarity.","Title: Processing analytical queries over encrypted data\nYear: 2013\n\nAbstract: MONOMI is a system for securely executing analytical workloads over sensitive data on an untrusted database server. MONOMI works by encrypting the entire database and running queries over the encrypted data. MONOMI introduces split client/server query execution, which can execute arbitrarily complex queries over encrypted data, as well as several techniques that improve performance for such workloads, including per-row precomputation, space-efficient encryption, grouped homomorphic addition, and pre-filtering. Since these optimizations are good for some queries but not others, MONOMI introduces a designer for choosing an efficient physical design at the server for a given workload, and a planner to choose an efficient execution plan for a given query at runtime. A prototype of MONOMI running on top of Postgres can execute most of the queries from the TPC-H benchmark with a median overhead of only 1.24× (ranging from 1.03×to 2.33×) compared to an un-encrypted Postgres database where a compromised server would reveal all data.","Title: Low overhead concurrency control for partitioned main memory databases\nYear: 2010\n\nAbstract: Database partitioning is a technique for improving the performance of distributed OLTP databases, since \"single partition\" transactions that access data on one partition do not need coordination with other partitions. For workloads that are amenable to partitioning, some argue that transactions should be executed serially on each partition without any concurrency at all. This strategy makes sense for a main memory database where there are no disk or user stalls, since the CPU can be fully utilized and the overhead of traditional concurrency control, such as two-phase locking, can be avoided. Unfortunately, many OLTP applications have some transactions which access multiple partitions. This introduces network stalls in order to coordinate distributed transactions, which will limit the performance of a database that does not allow concurrency. In this paper, we compare two low overhead concurrency control schemes that allow partitions to work on other transactions during network stalls, yet have little cost in the common case when concurrency is not needed. The first is a light-weight locking scheme, and the second is an even lighter-weight type of speculative concurrency control that avoids the overhead of tracking reads and writes, but sometimes performs work that eventually must be undone. We quantify the range of workloads over which each technique is beneficial, showing that speculative concurrency control generally outperforms locking as long as there are few aborts or few distributed transactions that involve multiple rounds of communication. On a modified TPC-C benchmark, speculative concurrency control can improve throughput relative to the other schemes by up to a factor of two.","Title: VoxNet: An Interactive, Rapidly-Deployable Acoustic Monitoring Platform\nYear: 2008\n\nAbstract: Distributed acoustic sensing underlies an increasingly important class of sensor network applications, from habitat monitoring and bio acoustic census to security applications and virtual fences. VoxNet is a complete hardware and software platform for distributed acoustic monitoring applications that focuses on three key goals:(1) rapid deployment in realistic environments;(2) a high level programming language that abstracts the user from platform and network details and compiles into a high performance distributed application; and(3) an interactive usage model based on run-time installable programs, with the ability to run the same high level program seamlessly over live or stored data. The VoxNet hardware is self-contained and weather-resistant, and supports a four-channel microphone array with automated time synchronization, localization, and network coordination. Using VoxNet, an investigator can visualize phenomena in real-time, develop and tune on-line analysis, and record raw data for off-line analysis and archival. This paper describes both the hardware and software elements of the platform, as well as the architecture required to support distributed programs running over a heterogeneous network.We characterize the performance of the platform, using both microbenchmarks that evaluate specific aspects of the platform and a real application running in the field.","Title: Scoop: An Adaptive Indexing Scheme For Stored Data In Sensor Networks\nYear: 2007\n\nAbstract: We present the design of Scoop, a system for indexing and querying stored data in sensor networks. Scoop works by collecting statistics about the rate of queries and distribution of sensor readings in a sensor network, and uses those statistics to build an index that tells nodes where in the network to store their data. Using this index, a queries over that stored data can be answered efficiently, without flooding those queries throughout the network. This approach offers a substantial advantage over other solutions that either store all data externally on a basestation (requiring every reading to be collected from all nodes), or that store all data locally on the node that produced it (requiring queries to be flooded throughout the network). Our results show that Scoop offers a factor of four reduction in message transmissions relative to existing techniques in a real implementation on a 64-node mote-based sensor network. These results also show that Scoop is able to efficiently adapt to changes in the distribution of data and queries.","Title: The end of an architectural era: (it's time for a complete rewrite)\nYear: 2007\n\nAbstract: In previous papers [SC05, SBC+07], some of us predicted the end of \"one size fits all\" as a commercial relational DBMS paradigm. These papers presented reasons and experimental evidence that showed that the major RDBMS vendors can be outperformed by 1--2 orders of magnitude by specialized engines in the data warehouse, stream processing, text, and scientific database markets. Assuming that specialized engines dominate these markets over time, the current relational DBMS code lines will be left with the business data processing (OLTP) market and hybrid markets where more than one kind of capability is required. In this paper we show that current RDBMSs can be beaten by nearly two orders of magnitude in the OLTP market as well. The experimental evidence comes from comparing a new OLTP prototype, H-Store, which we have built at M.I.T. to a popular RDBMS on the standard transactional benchmark, TPC-C. We conclude that the current RDBMS code lines, while attempting to be a \"one size fits all\" solution, in fact, excel at nothing. Hence, they are 25 year old legacy code lines that should be retired in favor of a collection of \"from scratch\" specialized engines. The DBMS vendors (and the research community) should start with a clean sheet of paper and design systems for tomorrow's requirements, not continue to push code lines and architectures designed for yesterday's needs.","Title: Materialization Strategies In A Column-Oriented Dbms\nYear: 2007\n\nAbstract: There has been renewed interest in column-oriented database architectures in recent years. For read-mostly query workloads such as those found in data warehouse and decision support applications, \"column-stores\" have been shown to perform particularly well relative to \"row-stores.\" In order for column-stores to be readily adopted as a replacement for row-stores, however, they must present the same interface to client applications as do row stores, which implies that they must output row-store-style tuples.Thus, the input columns stored on disk must be converted to rows at some point in the query plan, but the optimal point at which to do the conversion is not obvious. This problem can be considered as the opposite of the projection problem in row-store systems: while row-stores need to determine where in query plans to place projection operators to make tuples narrower, column-stores need to determine when to combine single-column projections into wider tuples. This paper describes a variety of strategies for tuple construction and intermediate result representations and provides a systematic evaluation of these strategies.","Title: The Case for a Signal-Oriented Data Stream Management System\nYear: 2007\n\nAbstract: Sensors capable of sensing phenomena at high data rates—on the order of tens to hundreds of thousands of samples per second—are useful in many industrial, civil engineering, scientific, networking, and medical applications. In these applications, high-rate streams of data produced by sensors must be processed and analyzed using a combination ofbothevent-stream and signal-processing operations. This paper motivates the need for a data management and continu- ous query processing architecture that integrates these two different desired classes of functions into a single, unified software system. The key goals of such a system include: the ability to treat a se- quence of samples that constitute a \"signal segment\" as a basic data type; ease of writing arbitrary event-stream and signal-processing functions; the ability to process several million samples per second on conventional PC hardware; and the ability to distribute applica- tion code across both PCs and sensor nodes.","Title: Using Probabilistic Models for Data Management in Acquisitional Environments\nYear: 2005\n\nAbstract: Traditional database systems, particularly those fo- cused on capturing and managing data from the real world, are poorly equipped to deal with the noise, loss, and uncertainty in data. We discuss a suite of techniques based on probabilistic models that are designed to allow database to tolerate noise and loss. These techniques are based on exploiting cor- relations to predict missing values and identify out- liers. Interestingly, correlations also provide a way to give approximate answers to users at a signifi- cantly lower cost and enable a range of new types of queries over the correlation structure itself. We illustrate a host of applications for our new tech- niques and queries, ranging from sensor networks to network monitoring to data stream management. We also present a unified architecture for integrat- ing such models into database systems, focusing in particular on acquisitional systems where the cost of capturing data (e.g., from sensors) is itself a sig- nificant part of the query processing cost.","Title: Human-powered sorts and joins\nYear: 2011\n\nAbstract: Crowdsourcing markets like Amazon's Mechanical Turk (MTurk) make it possible to task people with small jobs, such as labeling images or looking up phone numbers, via a programmatic interface. MTurk tasks for processing datasets with humans are currently designed with significant reimplementation of common workflows and ad-hoc selection of parameters such as price to pay per task. We describe how we have integrated crowds into a declarative workflow engine called Qurk to reduce the burden on workflow designers. In this paper, we focus on how to use humans to compare items for sorting and joining data, two of the most common operations in DBMSs. We describe our basic query interface and the user interface of the tasks we post to MTurk. We also propose a number of optimizations, including task batching, replacing pairwise comparisons with numerical ratings, and pre-filtering tables before joining them, which dramatically reduce the overall cost of running sorts and joins on the crowd. In an experiment joining two sets of images, we reduce the overall cost from $67 in a naive implementation to about $3, without substantially affecting accuracy or latency. In an end-to-end experiment, we reduced cost by a factor of 14.5.","Title: A demonstration of HYRISE: a main memory hybrid storage engine\nYear: 2011\n\nAbstract: AbstractWe propose to demonstrate HYRISE, a main memory hybrid database system, which automatically partitions tables into vertical partitions consisting of variable numbers of columns based on access patterns to each table. Using an accurate model of cache misses, HYRISE is able to predict the performance of different partitionings, and to automatically select the best partitions using an automated database partitioning algorithm. Our demonstration will show the results of the physical partitioning based on different query workloads, allowing demo attendees to visualize, fine-tune, and modify the partitioning using a GUI. It will then show how the various physical designs affect the query plans and the performance of the database as a whole. Attendees can thus experiment with various physical models, and can grasp the potential of hybrid partitionings, which achieve a 20% to 400% performance improvement over pure all-column or all-row designs on our realistic hybrid workload derived from customer applications.","Title: Continuously adaptive continuous queries over streams\nYear: 2002\n\nAbstract: We present a continuously adaptive, continuous query (CACQ) implementation based on the eddy query processing framework. We show that our design provides significant performance benefits over existing approaches to evaluating continuous queries, not only because of its adaptivity, but also because of the aggressive cross-query sharing of work and space that it enables. By breaking the abstraction of shared relational algebra expressions, our Telegraph CACQ implementation is able to share physical operators --- both selections and join state --- at a very fine grain. We augment these features with a grouped-filter index to simultaneously evaluate multiple selection predicates. We include measurements of the performance of our core system, along with a comparison to existing continuous query approaches.","Title: CHIC: a combination-based recommendation system\nYear: 2013\n\nAbstract: Current recommender systems are focused largely on recommending items based on similarity. For instance, Netflix can recommend movies similar to previously viewed movies, and Amazon can recommend items based on ratings of similar users. Although similarity-based recommendation works well for books and movies, it provides an incomplete solution for items such as clothing or furniture which are inherently used in combination with other items of the same type, e.g., shirt with pants, and desk with a chair. As a result, the decision to buy a clothing or furniture item depends not only on the item itself, but also on how well it works with other items of that type. Recommending such items therefore requires a combination-based recommendation system that given an item, can suggest interesting and diverse combinations containing that item. This problem is challenging because features affecting combination quality are often difficult to identify; quality, being a function of all items in the combination, cannot be computed independently; and there are an exponential number of combinations to explore. In this demonstration, we present CHIC, a first-of-its-kind, combination-based recommendation system for clothing. The audience will interact with our system through the CHIC mobile app which allows the user to take a picture of a clothing item and search for interesting combinations containing the item instantly. The audience can also compete with CHIC to create alternate ensembles and compare quality. Finally, we highlight via visualizations the core modules of CHIC including model building and our novel search and classification algorithm, C-Search.","Title: Automatic partitioning of database applications\nYear: 2012\n\nAbstract: Database-backed applications are nearly ubiquitous in our daily lives. Applications that make many small accesses to the database create two challenges for developers: increased latency and wasted resources from numerous network round trips. A well-known technique to improve transactional database application performance is to convert part of the application into stored procedures that are executed on the database server. Unfortunately, this conversion is often difficult. In this paper we describe Pyxis, a system that takes database-backed applications and automatically partitions their code into two pieces, one of which is executed on the application server and the other on the database server. Pyxis profiles the application and server loads, statically analyzes the code's dependencies, and produces a partitioning that minimizes the number of control transfers as well as the amount of data sent during each transfer. Our experiments using TPC-C and TPC-W show that Pyxis is able to generate partitions with up to 3x reduction in latency and 1.7x improvement in throughput when compared to a traditional non-partitioned implementation and has comparable performance to that of a custom stored procedure implementation.","Title: The Case for RodentStore, an Adaptive, Declarative Storage System\nYear: 2009\n\nAbstract: Recent excitement in the database community surrounding new applications?analytic, scientific, graph, geospatial, etc.?has led to an explosion in research on database storage systems. New storage systems are vital to the database community, as they are at the heart of making database systems perform well in new application domains. Unfortunately, each such system also represents a substantial engineering effort including a great deal of duplication of mechanisms for features such as transactions and caching. In this paper, we make the case for RodentStore, an adaptive and declarative storage system providing a high-level interface for describing the physical representation of data. Specifically, RodentStore uses a declarative storage algebra whereby administrators (or database design tools) specify how a logical schema should be grouped into collections of rows, columns, and/or arrays, and the order in which those groups should be laid out on disk. We describe the key operators and types of our algebra, outline the general architecture of RodentStore, which interprets algebraic expressions to generate a physical representation of the data, and describe the interface between RodentStore and other parts of a database system, such as the query optimizer and executor. We provide a case study of the potential use of RodentStore in representing dense geospatial data collected from a mobile sensor network, showing the ease with which different storage layouts can be expressed using some of our algebraic constructs and the potential performance gains that a RodentStore-built storage system can offer.","Title: Data management in sensor networks\nYear: 2006\n\nAbstract: This tutorial will cover recent topics in data management for sensor networks, focusing in particular on high-level systems and languages for querying stored and streaming data in such networks. We will begin with a survey of language proposals, including TinyDB, Cougar, Regions, and other more recent work, and will then examine a range of implementation issues that arise in such systems, including issues related to power efficiency, time synchronization, data collection and dissemination, fault-tolerance, and state management. After attending the tutorial, audience members should have a good understanding of the various systems in this space as well as an awareness of the technical issues that make building such systems difficult.","Title: Demonstration of the TrajStore system\nYear: 2009\n\nAbstract: The proliferation of GPS devices has led to a substantial interest in location based services. In particular, modern vehicles can generate an incredible amount of drive data. However, current storage systems are not optimized for storing and querying such large spatial-temporal data sets. In this demonstration, we show the performance of the TrajStore system, a dynamic storage system optimized for quickly accessing data in a particular spatial-temporal region. In particular, TrajStore uses a novel adaptive indexing technique that dynamically adjusts itself to co-locate spatially close trajectories on disk, as well as a number of compression techniques in the storage layer that significantly reduce access time for a given index cell. In this demonstration, we will store a set of real world taxi cab drive traces in TrajStore, and users will be able to query the data through a map based interface.","Title: Java support for data-intensive systems: experiences building the telegraph dataflow system\nYear: 2001\n\nAbstract: Database system designers have traditionally had trouble with the default services and interfaces provided by operating systems. In recent years, developers and enthusiasts have increasingly promoted Java as a serious platform for building data-intensive servers. Java provides a number of very helpful language features, as well as a full run-time environment reminiscent of a traditional operating system. This combination of features and community support raises the question of whether Java is better or worse at supporting data-intensive server software than a traditional operating system coupled with a weakly-typed language such as C or C++.In this paper, we summarize and discuss our experience building the Telegraph dataflow system in Java. We highlight some of the pleasures of coding with Java, and some of the pains of coding around Java in order to obtain good performance in a data-intensive server. For those issues that were painful, we present concrete suggestions for evolving Java's interfaces to better suit serious software systems development. We believe these experiences can provide insight for other designers to avoid pitfalls we encountered and to decide if Java is a suitable platform for their system.","Title: Performance profiling with EndoScope, an acquisitional software monitoring framework\nYear: 2008\n\nAbstract: We propose EndoScope, a software monitoring framework that allows users to pose declarative queries that monitor the state and performance of running programs. Unlike most existing monitoring tools, EndoScope is acquisitional, meaning that it only instruments the portions of the program that need to be monitored to answer queries. The use of a high level declarative language allows EndoScope to search for efficient physical instantiations of queries by applying a suite of optimizations, including control flow graph analysis, and traditional database query optimization techniques, such as predicate pushdown and join optimization, to minimize the number of program instrumentation points and overhead to the monitored program. Furthermore, a flexible, high level language and the ability to attach to running programs enable developers to build various program analysis and monitoring applications beyond traditional software profilers with EndoScope. We describe a prototype implementation of the EndoScope framework and a simple profiler for Java programs implemented with EndoScope. We show results from using our profiler on a collection of real-world programs, including a TPC-C implementation using the Derby database and the petstore application running on top of Tomcat application server. Our results show the benefit of our optimization framework and demonstrate that our declarative, acquisitional approach can yield program instrumentation overheads that are dramatically lower than conventional profiling tools (for example, when profiling the Derby Database running TPC-C, our system's overhead ranges from 1% to about 25%, whereas the fastest existing profiler we measured imposes a minimum overhead of about 30%.)","Title: CarTel: a distributed mobile sensor computing system\nYear: 2006\n\nAbstract: CarTel is a mobile sensor computing system designed to collect, process, deliver, and visualize data from sensors located on mobile units such as automobiles. A CarTel node is a mobile embedded computer coupled to a set of sensors. Each node gathers and processes sensor readings locally before delivering them to a central portal, where the data is stored in a database for further analysis and visualization. In the automotive context, a variety of on-board and external sensors collect data as users drive.CarTel provides a simple query-oriented programming interface, handles large amounts of heterogeneous data from sensors, and handles intermittent and variable network connectivity. CarTel nodes rely primarily on opportunistic wireless (e.g., Wi-Fi, Bluetooth) connectivity to the Internet, or to \"data mules\" such as other CarTel nodes, mobile phone flash memories, or USB keys-to communicate with the portal. CarTel applications run on the portal, using a delay-tolerant continuous query processor, ICEDB, to specify how the mobile nodes should summarize, filter, and dynamically prioritize data. The portal and the mobile nodes use a delay-tolerant network stack, CafNet, to communicat.CarTel has been deployed on six cars, running on a small scale in Boston and Seattle for over a year. It has been used to analyze commute times, analyze metropolitan Wi-Fi deployments, and for automotive diagnostics.","Title: Query Processing in Sensor Networks\nYear: 2003\n\nAbstract: Smart sensors are small, low-cost, wireless computing devices that sense information such as light and humidity at extremely high resolutions. Smart-sensor technology has enabled a broad range of ubiquitous computing applications, such as agricultural, industrial, and environmental monitoring. Because sensors collect and transmit information while managing limited power and radio bandwidth, traditional approaches for deploying these applications requires months of design and engineering time. A smart sensor query-processing architecture using database technology can, however, facilitate deployment of sensor networks greatly reducing programming effort and time-to-deployment for many such applications. The authors describe the design and implementation of an architecture to support the building of data-collection applications using sensors. Users specify the data of interest through simple, declarative queries, just as in a database system, and the infrastructure efficiently collects and processes the data within the sensor network.","Title: Tolerating byzantine faults in transaction processing systems using commit barrier scheduling\nYear: 2007\n\nAbstract: This paper describes the design, implementation, and evaluation of areplication scheme to handle Byzantine faults in transaction processing database systems. The scheme compares answers from queries and updates on multiple replicas which are unmodified, off-the-shelf systems, to provide a single database that is Byzantine fault tolerant. The scheme works when the replicas are homogeneous, but it also allows heterogeneous replication in which replicas come from different vendors. Heterogeneous replicas reduce the impact of bugs and security compromises because they are implemented independently and are thus less likely to suffer correlated failures. The main challenge in designing a replication scheme for transactionprocessing systems is ensuring that the different replicas execute transactions in equivalent serial orders while allowing a high degreeof concurrency. Our scheme meets this goal using a novel concurrency control protocol, commit barrier scheduling (CBS). We have implemented CBS in the context of a replicated SQL database, HRDB(Heterogeneous Replicated DB), which has been tested with unmodified production versions of several commercial and open source databases as replicas. Our experiments show an HRDB configuration that can tolerate one faulty replica has only a modest performance overhead(about 17% for the TPC-C benchmark). HRDB successfully masks several Byzantine faults observed in practice and we have used it to find a new bug in MySQL.","Title: PCP: the personal commute portal\nYear: 2008\n\nAbstract: The Personal Commute Portal (PCP) is a Web-based traffic information system that provides a good driving direction and personalized route recommendation using historical and real-time traffic data obtained by a vehicular sensor network.","Title: A trigger-based middleware cache for ORMs\nYear: 2011\n\nAbstract: Caching is an important technique in scaling storage for high-traffic web applications. Usually, building caching mechanisms involves significant effort from the application developer to maintain and invalidate data in the cache. In this work we present CacheGenie, a caching middleware which makes it easy for web application developers to use caching mechanisms in their applications. CacheGenie provides high-level caching abstractions for common query patterns in web applications based on Object-RelationalMapping (ORM) frameworks. Using these abstractions, the developer does not have to worry about managing the cache (e.g., insertion and deletion) or maintaining consistency (e.g., invalidation or updates) when writing application code. We design and implement CacheGenie in the popular Django web application framework, with PostgreSQL as the database backend and memcached as the caching layer. To automatically invalidate or update cached data, we use triggers inside the database. CacheGenie requires no modifications to PostgreSQL or memcached. To evaluate our prototype, we port several Pinax web applications to use our caching abstractions. Our results show that it takes little effort for application developers to use CacheGenie, and that CacheGenie improves throughput by 2-2.5× for read-mostly workloads in Pinax.","Title: Demonstration of Qurk: a query processor for humanoperators\nYear: 2011\n\nAbstract: Crowdsourcing technologies such as Amazon's Mechanical Turk (\"MTurk\") service have exploded in popularity in recent years. These services are increasingly used for complex human-reliant data processing tasks, such as labelling a collection of images, combining two sets of images to identify people that appear in both, or extracting sentiment from a corpus of text snippets. There are several challenges in designing a workflow that filters, aggregates, sorts and joins human-generated data sources. Currently, crowdsourcing-based workflows are hand-built, resulting in increasingly complex programs. Additionally, developers must hand-optimize tradeoffs among monetary cost, accuracy, and time to completion of results. These challenges are well-suited to a declarative query interface that allows developers to describe their worflow at a high level and automatically optimizes workflow and tuning parameters. In this demonstration, we will present Qurk, a novel query system that allows human-based processing for relational databases. The audience will interact with the system to build queries and monitor their progress. The audience will also see Qurk from an MTurk user's perspective, and complete several tasks to better understand how a query is processed.","Title: XStream: a Signal-Oriented Data Stream Management System\nYear: 2008\n\nAbstract: Sensors capable of sensing phenomena at high data rates on the order of tens to hundreds of thousands of samples per second are now widely deployed in many industrial, civil engineering, scientific, networking, and medical applications. In aggregate, these sensors easily generate several million samples per second that must be processed within milliseconds or seconds. The computation required includes both signal processing and event stream processing. XStream is a stream processing system for such applications. XStream introduces a new data type, the signal segment, which allows applications to manipulate isochronous (regularly spaced in time) collections of sensor samples more conveniently and efficiently than the asynchronous representation used in previous work. XStream includes a memory manager and scheduler optimizations tuned for processing signal segments at high speeds. In benchmark comparisons, we show that XStream outperforms a leading commercial stream processing system by more than three orders of magnitude. On one application, the commercial system processed 72.7 Ksamples/sec, while XStream processed 97.6 Msamples/sec.","Title: CARTILAGE: adding flexibility to the Hadoop skeleton\nYear: 2013\n\nAbstract: Modern enterprises have to deal with a variety of analytical queries over very large datasets. In this respect, Hadoop has gained much popularity since it scales to thousand of nodes and terabytes of data. However, Hadoop suffers from poor performance, especially in I/O performance. Several works have proposed alternate data storage for Hadoop in order to improve the query performance. However, many of these works end up making deep changes in Hadoop or HDFS. As a result, they are (i) difficult to adopt by several users, and (ii) not compatible with future Hadoop releases. In this paper, we present CARTILAGE, a comprehensive data storage framework built on top of HDFS. CARTILAGE allows users full control over their data storage, including data partitioning, data replication, data layouts, and data placement. Furthermore, CARTILAGE can be layered on top of an existing HDFS installation. This means that Hadoop, as well as other query engines, can readily make use of CARTILAGE. We describe several use-cases of CARTILAGE and propose to demonstrate the flexibility and efficiency of CARTILAGE through a set of novel scenarios.","Title: The pothole patrol: using a mobile sensor network for road surface monitoring\nYear: 2008\n\nAbstract: This paper investigates an application of mobile sensing: detecting and reporting the surface conditions of roads. We describe a system and associated algorithms to monitor this important civil infrastructure using a collection of sensor-equipped vehicles. This system, which we call the Pothole Patrol (P2), uses the inherent mobility of the participating vehicles, opportunistically gathering data from vibration and GPS sensors, and processing the data to assess road surface conditions. We have deployed P2 on 7 taxis running in the Boston area. Using a simple machine-learning approach, we show that we are able to identify potholes and other severe road surface anomalies from accelerometer data. Via careful selection of training data and signal features, we have been able to build a detector that misidentifies good road segments as having potholes less than 0.2% of the time. We evaluate our system on data from thousands of kilometers of taxi drives, and show that it can successfully detect a number of real potholes in and around the Boston area. After clustering to further reduce spurious detections, manual inspection of reported potholes shows that over 90% contain road anomalies in need of repair.","Title: An integrated approach to recovery and high availability in an updatable, distributed data warehouse\nYear: 2006\n\nAbstract: Any highly available data warehouse will use some form of data replication to tolerate machine failures. In this paper, we demonstrate that we can leverage this data redundancy to build an integrated approach to recovery and high availability. Our approach, called HARBOR, revives a crashed site by querying remote, online sites for missing updates and uses timestamps to determine which tuples need to be copied or updated. HARBOR does not require a stable log, recovers without quiescing the system, allows replicated data to be stored non-identically, and is simpler than a log-based recovery algorithm.We compare the runtime overhead and recovery performance of HARBOR to those of two-phase commit and ARIES, the gold standard for log-based recovery, on a three-node distributed database system. Our experiments demonstrate that HARBOR suffers lower runtime overhead, has recovery performance comparable to ARIES's, and can tolerate the fault of a worker and efficiently bring it back online.","Title: MDCC: multi-data center consistency\nYear: 2013\n\nAbstract: Replicating data across multiple data centers allows using data closer to the client, reducing latency for applications, and increases the availability in the event of a data center failure. MDCC (Multi-Data Center Consistency) is an optimistic commit protocol for geo-replicated transactions, that does not require a master or static partitioning, and is strongly consistent at a cost similar to eventually consistent protocols. MDCC takes advantage of Generalized Paxos for transaction processing and exploits commutative updates with value constraints in a quorum-based system. Our experiments show that MDCC outperforms existing synchronous transactional replication protocols, such as Megastore, by requiring only a single message round-trip in the normal operational case independent of the master-location and by scaling linearly with the number of machines as long as transaction conflict rates permit.","Title: Correlation maps: a compressed access method for exploiting soft functional dependencies\nYear: 2009\n\nAbstract: In relational query processing, there are generally two choices for access paths when performing a predicate lookup for which no clustered index is available. One option is to use an unclustered index. Another is to perform a complete sequential scan of the table. Many analytical workloads do not benefit from the availability of unclustered indexes; the cost of random disk I/O becomes prohibitive for all but the most selective queries. It has been observed that a secondary index on an unclustered attribute can perform well under certain conditions if the unclustered attribute is correlated with a clustered index attribute [4]. The clustered index will co-locate values and the correlation will localize access through the unclustered attribute to a subset of the pages. In this paper, we show that in a real application (SDSS) and widely used benchmark (TPC-H), there exist many cases of attribute correlation that can be exploited to accelerate queries. We also discuss a tool that can automatically suggest useful pairs of correlated attributes. It does so using an analytical cost model that we developed, which is novel in its awareness of the effects of clustering and correlation. Furthermore, we propose a data structure called a Correlation Map (CM) that expresses the mapping between the correlated attributes, acting much like a secondary index. The paper also discusses how bucketing on the domains of both attributes in the correlated attribute pair can dramatically reduce the size of the CM to be potentially orders of magnitude smaller than that of a secondary B+Tree index. This reduction in size allows us to create a large number of CMs that improve performance for a wide range of queries. The small size also reduces maintenance costs as we demonstrate experimentally.","Title: Accurate, low-energy trajectory mapping for mobile devices\nYear: 2011\n\nAbstract: CTrack is an energy-efficient system for trajectory mapping using raw position tracks obtained largely from cellular base station fingerprints. Trajectory mapping, which involves taking a sequence of raw position samples and producing the most likely path followed by the user, is an important component in many location-based services including crowd-sourced traffic monitoring, navigation and routing, and personalized trip management. Using only cellular (GSM) fingerprints instead of power-hungry GPS and WiFi radios, the marginal energy consumed for trajectory mapping is zero. This approach is non-trivial because we need to process streams of highly inaccurate GSM localization samples (average error of over 175 meters) and produce an accurate trajectory. CTrack meets this challenge using a novel two-pass Hidden Markov Model that sequences cellular GSM fingerprints directly without converting them to geographic coordinates, and fuses data from low-energy sensors available on most commodity smart-phones, including accelerometers (to detect movement) and magnetic compasses (to detect turns). We have implemented CTrack on the Android platform, and evaluated it on 126 hours (1,074 miles) of real driving traces in an urban environment. We find that CTrack can retrieve over 75% of a user's drive accurately in the median. An important by-product of CTrack is that even devices with no GPS or WiFi (constituting a significant fraction of today's phones) can contribute and benefit from accurate position data.","Title: Wishbone: profile-based partitioning for sensornet applications\nYear: 2009\n\nAbstract: The ability to partition sensor network application code across sensor nodes and backend servers is important for running complex, data-intensive applications on sensor platforms that have CPU, energy, and bandwidth limitations. This paper presents Wishbone, a system that takes a dataflow graph of operators and produces an optimal partitioning. With Wishbone, users can run the same program on a range of sensor platforms, including TinyOS motes, smartphones running JavaME, and the iPhone. The resulting program partitioning will in general be different in each case, reflecting the different node capabilities. Wishbone uses profiling to determine how each operator in the dataflow graph will actually perform on sample data, without requiring cumbersome user annotations. Its partitioning algorithm models the problem as an integer linear program that minimizes a linear combination of network bandwidth and CPU load and uses program structure to solve the problem efficiently in practice. Our results on a speech detection application show that the system can quickly identify good trade-offs given limitations in CPU and network capacity.","Title: The Claremont report on database research\nYear: 2008\n\nAbstract: In late May, 2008, a group of database researchers, architects, users and pundits met at the Claremont Resort in Berkeley, California to discuss the state of the research field and its impacts on practice. This was the seventh meeting of this sort in twenty years, and was distinguished by a broad consensus that we are at a turning point in the history of the field, due both to an explosion of data and usage scenarios, and to major shifts in computing hardware and platforms. Given these forces, we are at a time of opportunity for research impact, with an unusually large potential for influential results across computing, the sciences and society. This report details that discussion, and highlights the group's consensus view of new focus areas, including new database engine architectures, declarative programming languages, the interplay of structured and unstructured data, cloud data services, and mobile and virtual worlds. We also report on discussions of the community's growth, including suggestions for changes in community processes to move the research agenda forward, and to enhance impact on a broader audience.","Title: WaveScope: a signal-oriented data stream management system\nYear: 2006\n\nAbstract: WaveScope is a data management and continuous sensor data system that integrates relational database and signal processing operations into a single system. WaveScope is motivated by a large number of signal-oriented streaming sensor applications, such as: preventive maintenance of industrial equipment; detection of fractures and ruptures in various structures; in situ animal behavior studies using acoustic sensing; network traffic analysis; and medical applications such as anomaly detection in EKGs. These target applications use a variety of embedded sensors, each sampling at fine resolution and producing data at high rates ranging from hundreds to hundreds of thousands of samples per second. Though there has been some work on applications in the sensor network community that do this kind of signal processing (for example, shooter localization [5], industrial equipment monitoring [4], and urban infrastructure monitoring [2]), these applications are typically custombuilt and do not provide reusable high-level programming framework suitable for easily building new signal processing applications with similar functionality. This poster shows how WaveScope supports these types of application in a single, unified framework, providing both high run-time performance and easy application development.","Title: Speedy transactions in multicore in-memory databases\nYear: 2013\n\nAbstract: Silo is a new in-memory database that achieves excellent performance and scalability on modern multicore machines. Silo was designed from the ground up to use system memory and caches efficiently. For instance, it avoids all centralized contention points, including that of centralized transaction ID assignment. Silo's key contribution is a commit protocol based on optimistic concurrency control that provides serializability while avoiding all shared-memory writes for records that were only read. Though this might seem to complicate the enforcement of a serial order, correct logging and recovery is provided by linking periodically-updated epochs with the commit protocol. Silo provides the same guarantees as any serializable database without unnecessary scalability bottlenecks or much additional latency. Silo achieves almost 700,000 transactions per second on a standard TPC-C workload mix on a 32-core machine, as well as near-linear scalability. Considered per core, this is several times higher than previously reported results.","Title: Supporting Aggregate Queries Over Ad-Hoc Wireless Sensor Networks\nYear: 2002\n\nAbstract: We show how the database community's notion of a generic query interface for data aggregation can be applied to ad-hoc networks of sensor devices. As has been noted in the sensor network literature, aggregation is important as a data reduction tool; networking approaches, however, have focused on application specific solutions, whereas our in-network aggregation approach is driven by a general purpose, SQL-style interface that can execute queries over any type of sensor data while providing opportunities for significant optimization. We present a variety of techniques to improve the reliability and performance of our solution. We also show how grouped aggregates can be efficiently computed and offer a comparison to related systems and database projects.","Title: Scorpion: explaining away outliers in aggregate queries\nYear: 2013\n\nAbstract: Database users commonly explore large data sets by running aggregate queries that project the data down to a smaller number of points and dimensions, and visualizing the results. Often, such visualizations will reveal outliers that correspond to errors or surprising features of the input data set. Unfortunately, databases and visualization systems do not provide a way to work backwards from an outlier point to the common properties of the (possibly many) unaggregated input tuples that correspond to that outlier. We propose Scorpion, a system that takes a set of user-specified outlier points in an aggregate query result as input and finds predicates that explain the outliers in terms of properties of the input tuples that are used to compute the selected outlier results. Specifically, this explanation identifies predicates that, when applied to the input data, cause the outliers to disappear from the output. To find such predicates, we develop a notion of influence of a predicate on a given output, and design several algorithms that efficiently search for maximum influence predicates over the input data. We show that these algorithms can quickly find outliers in two real data sets (from a sensor deployment and a campaign finance data set), and run orders of magnitude faster than a naive search algorithm while providing comparable quality on a synthetic data set.","Title: Improving wireless network performance using sensor hints\nYear: 2011\n\nAbstract: With the proliferation of mobile wireless devices such as smartphones and tablets that are used in a wide range of locations and movement conditions, it has become important for wireless protocols to adapt to different settings over short periods of time. Network protocols that perform well in static settings where channel conditions are relatively stable tend to perform poorly in mobile settings where channel conditions change rapidly, and vice versa. To adapt to the conditions under which communication is occurring, we propose the use of external sensor hints to augment network protocols. Commodity smartphones and tablet devices come equipped with a variety of sensors, including GPS, accelerometers, magnetic compasses, and gyroscopes, which can provide hints about the device's mobility state and its operating environment. We present a wireless protocol architecture that integrates sensor hints in adaptation algorithms. We validate the idea and architecture by implementing and evaluating sensor-augmented wireless protocols for bit rate adaptation, access point association, neighbor maintenance in mobile mesh networks, and path selection in vehicular networks.","Title: Thinking Big About Tiny Databases\nYear: 2007\n\nAbstract: Work on early tiny database systems, like TinyDB (17) and Cougar (23) has shown that a declar- ative approach can provide a powerful and easy to use interface for collecting data from static sensor networks. These early systems, however, have significant limitations; in particular, they are useful only for low-rate data collection applications on static sensor networks and they don't integrate well with existing database and IT tools. In this paper, we discuss recent research that has addressed these limi- tations, showing that similar \"tiny database thinking\" can provide solutions to much bigger problems, including network protocol specification and mobile and high data rate signal-oriented data processing.","Title: Stochastic motion planning and applications to traffic\nYear: 2011\n\nAbstract: This paper presents a stochastic motion planning algorithm and its application to traffic navigation. The algorithm copes with the uncertainty of road traffic conditions by stochastic modeling of travel delay on road networks. The algorithm determines paths between two points that optimize a cost function of the delay probability distribution. It c an be used to find paths that maximize the probability of reaching a destination within a partic ular travel deadline. For such problems, standard shortest-path algorithms don't work because the optimal substructure property doesn't hold. We evaluate our algorithm using bo th simulations and real- world drives, using delay data gathered from a set of taxis equipped with GPS sensors and a wireless network. Our algorithm can be integrated into on-board navigation systems as well as route-finding Web sites, providing drivers with good paths that meet th eir desired goals. This paper presents and evaluates an algorithm for planning the motion of vehicles (autonomous or human-driven) on roadways in the face of traffic delays. Rather than model road delays statically, as in current on-board navigation systems and Web- based mapping services, our algorithm uses past observations of actual delays on road segments to model these delays as probability distributions. The algorithm min- imizes a user-specified cost function of the delay distribut ion. We investigate a few cost functions in detail, particularly one that is equivale nt to maximizing the likeli- hood of reaching a destination within a specified travel dead line. Our work provides a planning system that can be used by robots as well as hu- man drivers. The system is a useful addition to on-board navigation systems us- ing computer-aided automation to provide good paths that meet desired travel goals (e.g., \"when should you leave, and what path should you take, to reach the airport by 8am with high probability?\"); it is also a worthwhile addition to Web-based map- ping services. We view the incorporation of traffic-aware pa th computation as an important practical addition in the rapid trend toward computer-assisted driving and autonomous decision-making in vehicles. Traffic congestion is clearly a serious problem: a recent sur vey (11) estimates that the annual nationwide cost of traffic congestion is $78 billi on, including 4.2 billion hours in lost time and 2.9 billion gallons in wasted fuel. Drivers today have little knowledge of historic and real-time traffic congestion on th e paths they drive, and","Title: H-store: a high-performance, distributed main memory transaction processing system\nYear: 2008\n\nAbstract: Our previous work has shown that architectural and application shifts have resulted in modern OLTP databases increasingly falling short of optimal performance [10]. In particular, the availability of multiple-cores, the abundance of main memory, the lack of user stalls, and the dominant use of stored procedures are factors that portend a clean-slate redesign of RDBMSs. This previous work showed that such a redesign has the potential to outperform legacy OLTP databases by a significant factor. These results, however, were obtained using a bare-bones prototype that was developed just to demonstrate the potential of such a system. We have since set out to design a more complete execution platform, and to implement some of the ideas presented in the original paper. Our demonstration presented here provides insight on the development of a distributed main memory OLTP database and allows for the further study of the challenges inherent in this operating environment.","Title: BlinkDB: queries with bounded errors and bounded response times on very large data\nYear: 2013\n\nAbstract: In this paper, we present BlinkDB, a massively parallel, approximate query engine for running interactive SQL queries on large volumes of data. BlinkDB allows users to trade-off query accuracy for response time, enabling interactive queries over massive data by running queries on data samples and presenting results annotated with meaningful error bars. To achieve this, BlinkDB uses two key ideas: (1) an adaptive optimization framework that builds and maintains a set of multi-dimensional stratified samples from original data over time, and (2) a dynamic sample selection strategy that selects an appropriately sized sample based on a query's accuracy or response time requirements. We evaluate BlinkDB against the well-known TPC-H benchmarks and a real-world analytic workload derived from Conviva Inc., a company that manages video distribution over the Internet. Our experiments on a 100 node cluster show that BlinkDB can answer queries on up to 17 TBs of data in less than 2 seconds (over 200 x faster than Hive), within an error of 2-10%.","Title: A comparison of approaches to large-scale data analysis\nYear: 2009\n\nAbstract: There is currently considerable enthusiasm around the MapReduce (MR) paradigm for large-scale data analysis [17]. Although the basic control flow of this framework has existed in parallel SQL database management systems (DBMS) for over 20 years, some have called MR a dramatically new computing model [8, 17]. In this paper, we describe and compare both paradigms. Furthermore, we evaluate both kinds of systems in terms of performance and development complexity. To this end, we define a benchmark consisting of a collection of tasks that we have run on an open source version of MR as well as on two parallel DBMSs. For each task, we measure each system's performance for various degrees of parallelism on a cluster of 100 nodes. Our results reveal some interesting trade-offs. Although the process to load data into and tune the execution of parallel DBMSs took much longer than the MR system, the observed performance of these DBMSs was strikingly better. We speculate about the causes of the dramatic performance difference and consider implementation concepts that future systems should take from both kinds of architectures.","Title: Integrating compression and execution in column-oriented database systems\nYear: 2006\n\nAbstract: Column-oriented database system architectures invite a re-evaluation of how and when data in databases is compressed. Storing data in a column-oriented fashion greatly increases the similarity of adjacent records on disk and thus opportunities for compression. The ability to compress many adjacent tuples at once lowers the per-tuple cost of compression, both in terms of CPU and space overheads.In this paper, we discuss how we extended C-Store (a column-oriented DBMS) with a compression sub-system. We show how compression schemes not traditionally used in row-oriented DBMSs can be applied to column-oriented systems. We then evaluate a set of compression schemes and show that the best scheme depends not only on the properties of the data but also on the nature of the query workload.","Title: Beyond average: toward sophisticated sensing with queries\nYear: 2003\n\nAbstract: High-level query languages are an attractive interface for sensor networks, potentially relieving application programmers from the burdens of distributed, embedded programming. In research to date, however, the proposed applications of such interfaces have been limited to simple data collection and aggregation schemes. In this paper, we present initial results that extend the TinyDB sensornet query engine to support more sophisticated data analyses, focusing on three applications: topographic mapping, wavelet-based compression, and vehicle tracking. We use these examples to motivate the feasibility of implementing sophisticated sensing applications in a query-based system, and present some initial results and research questions raised by this agenda.","Title: Inferring SQL Queries Using Program Synthesis\nYear: 2012\n\nAbstract: Developing high-performance applications that interact with databases is a difficult task, as developers need to understand both the details of the language in which their applications are written in, and also the intricacies of the relational model. One popular solution to this problem is the use of object-relational mapping (ORM) libraries that provide transparent access to the database using the same language that the application is written in. Unfortunately, using such frameworks can easily lead to applications with poor performance because developers often end up implementing relational operations in application code, and doing so usually does not take advantage of the optimized implementations of relational operations, efficient query plans, or push down of predicates that database systems provide. In this paper we present QBS, an algorithm that automatically identifies fragments of application logic that can be pushed into SQL queries. The QBS algorithm works by automatically synthesizing invariants and postconditions for the original code fragment. The postconditions and invariants are expressed using a theory of ordered relations that allows us to reason precisely about the contents and order of the records produced even by complex code fragments that compute joins and aggregates. The theory is close in expressiveness to SQL, so the synthesized postconditions can be readily translated to SQL queries. Using 40 code fragments extracted from over 120k lines of open-source code written using the Java Hibernate ORM, we demonstrate that our approach can convert a variety of imperative constructs into relational specifications.","Title: Code in the air: simplifying sensing and coordination tasks on smartphones\nYear: 2012\n\nAbstract: A growing class of smartphone applications are tasking applications that run continuously, process data from sensors to determine the user's context (such as location) and activity, and optionally trigger certain actions when the right conditions occur. Many such tasking applications also involve coordination between multiple users or devices. Example tasking applications include location-based reminders, changing the ring-mode of a phone automatically depending on location, notifying when friends are nearby, disabling WiFi in favor of cellular data when moving at more than a certain speed outdoors, automatically tracking and storing movement tracks when driving, and inferring the number of steps walked each day. Today, these applications are non-trivial to develop, although they are often trivial for end users to state. Additionally, simple implementations can consume excessive amounts of energy. This paper proposes Code in the Air (CITA), a system which simplifies the rapid development of tasking applications. It enables non-expert end users to easily express simple tasks on their phone, and more sophisticated developers to write code for complex tasks by writing purely server-side scripts. CITA provides a task execution framework to automatically distribute and coordinate tasks, energy-efficient modules to infer user activities and compose them, and a push communication service for mobile devices that overcomes some shortcomings in existing push services.","Title: Report on the Fourth International Workshop on Data Management for Sensor Networks (DMSN 2007)\nYear: 2007\n\nAbstract: Sensor networks enable an unprecedented level of access to the physical world, and hold tremendous potential to revolutionize many application domains. Research on sensor networks spans many areas of computer science, and there are now major conferences, e.g., IPSN and SenSys, devoted to sensor networks. However, there is no focused forum for discussion of early and innovative work on data management in sensor networks. The International Workshop on Data Management for Sensor Networks (DMSN), inaugurated in 2004, aims to fill this significant gap in the database and sensor network communities.","Title: Top-k queries on uncertain data: on score distribution and typical answers\nYear: 2009\n\nAbstract: Uncertain data arises in a number of domains, including data integration and sensor networks. Top-k queries that rank results according to some user-defined score are an important tool for exploring large uncertain data sets. As several recent papers have observed, the semantics of top-k queries on uncertain data can be ambiguous due to tradeoffs between reporting high-scoring tuples and tuples with a high probability of being in the resulting data set. In this paper, we demonstrate the need to present the score distribution of top-k vectors to allow the user to choose between results along this score-probability dimensions. One option would be to display the complete distribution of all potential top-k tuple vectors, but this set is too large to compute. Instead, we propose to provide a number of typical vectors that effectively sample this distribution. We propose efficient algorithms to compute these vectors. We also extend the semantics and algorithms to the scenario of score ties, which is not dealt with in the previous work in the area. Our work includes a systematic empirical study on both real dataset and synthetic datasets.","Title: PAQ: time series forecasting for approximate query answering in sensor networks\nYear: 2006\n\nAbstract: In this paper, we present a method for approximating the values of sensors in a wireless sensor network based on time series forecasting. More specifically, our approach relies on autoregressive models built at each sensor to predict local readings. Nodes transmit these local models to a sink node, which uses them to predict sensor values without directly communicating with sensors. When needed, nodes send information about outlier readings and model updates to the sink. We show that this approach can dramatically reduce the amount of communication required to monitor the readings of all sensors in a network, and demonstrate that our approach provides provably-correct, user-controllable error bounds on the predicted values of each sensor.","Title: TAG: a Tiny AGgregation service for ad-hoc sensor networks\nYear: 2002\n\nAbstract: We present the Tiny AGgregation (TAG) service for aggregation in low-power, distributed, wireless environments. TAG allows users to express simple, declarative queries and have them distributed and executed efficiently in networks of low-power, wireless sensors. We discuss various generic properties of aggregates, and show how those properties affect the performance of our in network approach. We include a performance study demonstrating the advantages of our approach over traditional centralized, out-of-network methods, and discuss a variety of optimizations for improving the performance and fault tolerance of the basic solution.","Title: Using program synthesis for social recommendations\nYear: 2012\n\nAbstract: This paper presents a new approach to select events of interest to users in a social media setting where events are generated from mobile devices. We argue that the problem is best solved by inductive learning, where the goal is to first generalize from the users' expressed \"likes\" and \"dislikes\" of specific events, then to produce a program that can be used to collect only data of interest. The key contribution of this paper is a new algorithm that combines machine learning techniques with program synthesis technology to learn users' preferences. We show that when compared with the more standard approaches, our new algorithm provides up to order-of-magnitude reductions in model training time, and significantly higher prediction accuracies for our target application.1","Title: HYRISE: a main memory hybrid storage engine\nYear: 2010\n\nAbstract: In this paper, we describe a main memory hybrid database system called HYRISE, which automatically partitions tables into vertical partitions of varying widths depending on how the columns of the table are accessed. For columns accessed as a part of analytical queries (e.g., via sequential scans), narrow partitions perform better, because, when scanning a single column, cache locality is improved if the values of that column are stored contiguously. In contrast, for columns accessed as a part of OLTP-style queries, wider partitions perform better, because such transactions frequently insert, delete, update, or access many of the fields of a row, and co-locating those fields leads to better cache locality. Using a highly accurate model of cache misses, HYRISE is able to predict the performance of different partitionings, and to automatically select the best partitioning using an automated database design algorithm. We show that, on a realistic workload derived from customer applications, HYRISE can achieve a 20% to 400% performance improvement over pure all-column or all-row designs, and that it is both more scalable and produces better designs than previous vertical partitioning approaches for main memory systems.","Title: CrowdDB: query processing with the VLDB crowd\nYear: 2011\n\nAbstract: AbstractDatabases often give incorrect answers when data are missing or semantic understanding of the data is required. Processing such queries requires human input for providing the missing information, for performing computationally difficult functions, and for matching, ranking, or aggregating results based on fuzzy criteria. In this demo we present CrowdDB, a hybrid database system that automatically uses crowdsourcing to integrate human input for processing queries that a normal database system cannot answer.CrowdDB uses SQL both as a language to ask complex queries and as a way to model data stored electronically and provided by human input. Furthermore, queries are automatically compiled and optimized. Special operators provide user interfaces in order to integrate and cleanse human input. Currently CrowdDB supports two crowdsourcing platforms: Amazon Mechanical Turk and our own mobile phone platform. During the demo, the mobile platform will allow the VLDB crowd to participate as workers and help answer otherwise impossible queries.","Title: Data Management Issues in Disconnected Sensor Networks\nYear: 2004\n\nAbstract: The possibility of disconnection is one of the fundamental new network- ing problems presented by sensor networks. The goal of this paper is to address the problem of result collection in periodically disconnectedsensor networks, focusing, in particular, on opportunities for in-network processing. Our hypothesis is that, through careful augmentation of the networking layer underneath the declarative query proces- sor, it will be possible to expose information that will make the query processor able to adapt to and handle disconnections.","Title: TOADS: A Two-Dimensional Open-Ended Architectural Database System\nYear: 2001\n\nAbstract: The TOADS system is an innovative tool for building interior-space virtual environments (VEs) in two dimensions. Existing VE design tools typically operate in three dimensions, which makes it difficult to manipulate objects on the inherently two-dimensional computer screen. TOADS allows nearly the same functionality as those three-dimensional systems in an easy-to-use, two-dimensional environment. Users edit and enhance DXF floorplans with height and texture information. The software includes an inference engine that automatically identifies doors in the floorplan and generates openable polygons in the final environment. It also includes a sophisticated mechanism for embedding complex textures, such as transparent windows, at arbitrary heights in wall polygons. The entire interface is integrated with software that drives a custom texture-acquisition device. This device consists of a rack-mounted camera that captures narrow bands of textures and tiles them together to form long, continuous swaths of texture. This paper summarizes these tools and their function, and presents examples of environments that were generated with them.","Title: REED: robust, efficient filtering and event detection in sensor networks\nYear: 2005\n\nAbstract: This paper presents a set of algorithms for efficiently evaluating join queries over static data tables in sensor networks. We describe and evaluate three algorithms that take advantage of distributed join techniques. Our algorithms are capable of running in limited amounts of RAM, can distribute the storage burden over groups of nodes, and are tolerant to dropped packets and node failures. REED is thus suitable for a wide range of event-detection applications that traditional sensor network database and data collection systems cannot be used to implement.","Title: Icedb: Intermittently-Connected Continuous Query Processing\nYear: 2007\n\nAbstract: Current distributed database and stream processing systems assume that the network connecting nodes in the data Processor is \"always on,\" and that the absence of a network connection is a fault that needs to be masked to avoid failure. Several emerging wireless sensor network applications must cope with a combination of node mobility (e.g., sensors on moving cars) and high data rates (media-rich sensors capturing videos, images, sounds, etc.). Due to their mobility, these sensor networks display intermittent and variable network connectivity, and often have to deliver large quantities of data relative to the bandwidth available during periods of connectivity.This paper describes ICEDB (Intermittently Connected Embedded Database), a continuous query processing system for intermittently connected mobile sensor networks. ICEDB incorporates two key ideas: (1) a delay-tolerant continuous query processor, coordinated by a central server and distributed across the mobile nodes, and (2) algorithms for Prioritizing certain query results to improve application-defined \"utility\" metrics. We describe the results of several experiments that use data collected from a small deployed network of six cars driving in and around Boston and Seattle.","Title: A measurement-based analysis of the interaction between network layers in TinyOS\nYear: 2006\n\nAbstract: There have been a number of recent proposals for link and network-layer protocols in the sensor networking literature, each of which claims to be superior to other approaches. However, a proposal for a networking protocol at a given layer in the stack is typically evaluated in the context of a single set of carefully selected protocols at other layers. Because of the limited data available about interactions between different protocols at various layers of the stack, it is difficult for developers of sensor network applications to select from amongst the range of alternative sensor networking protocols. This paper evaluates the interaction between several protocols at the MAC and network layers measuring their performance in terms of end-to-end throughput and loss on a large testbed. We identify some common sources of poor performance; based on this experience, we propose a set of design principles for the designers of future interfaces.","Title: Speeding up database applications with Pyxis\nYear: 2013\n\nAbstract: We propose to demonstrate Pyxis, a system that optimizes database applications by pushing computation to the database server. Our system applies program analysis techniques to the application source code to determine pieces of application logic that should be moved to the database server to improve performance. This frees the developer from the need to understand the intricacies of database operations or learn a new programming language for stored procedures. In addition, by dynamically monitoring resource utilization on the database server, Pyxis can migrate computation between application and database in response to workload changes. Our previous experiments have shown that Pyxis can decrease latency up to 3x for transactional applications, and improve throughput up to 1.7x when compared to a standard implementation using embedded SQL statements in application logic. We will demonstrate these capabilities via a visualization of real-time performance as well as an interactive code partitioning tool we have developed.","Title: TelegraphCQ: Continuous Dataflow Processing for an Uncertain World.\nYear: 2003\n\nAbstract: Increasingly pervasive networks are leading towards a world where data is constantly in motion. In such a world, conventional techniques for query processing, which were developed under the assumption of a far more static and predictable computational environment, will not be sufficient. Instead, query processors based on adaptive dataflow will be necessary. The Telegraph project has developed a suite of novel technologies for continuously adaptive query processing. The next generation Telegraph system, called TelegraphCQ, is focused on meeting the challenges that arise in handling large streams of continuous queries over high-volume, highly-variable data streams. In this paper, we describe the system architecture and its underlying technology, and report on our ongoing implementation effort, which leverages the PostgreSQL open source code base. We also discuss open issues and our research agenda.","Title: VERTEXICA: Your Relational Friend for Graph Analytics!\nYear: 2014\n\nAbstract: In this paper, we present Vertexica, a graph analytics tools on top of a relational database, which is user friendly and yet highly efficient. Instead of constraining programmers to SQL, Vertexica offers a popular vertex-centric query interface, which is more natural for analysts to express many graph queries. The programmers simply provide their vertex-compute functions and Vertexica takes care of efficiently executing them in the standard SQL engine. The advantage of using Vertexica is its ability to leverage the relational features and enable much more sophisticated graph analysis. These include expressing graph algorithms which are difficult in vertex-centric but straightforward in SQL and the ability to compose end-to-end data processing pipelines, including pre- and post- processing of graphs as well as combining multiple algorithms for deeper insights. Vertexica has a graphical user interface and we outline several demonstration scenarios including, interactive graph analysis, complex graph analysis, and continuous and time series analysis.","Title: SeeDB: automatically generating query visualizations\nYear: 2014\n\nAbstract: Data analysts operating on large volumes of data often rely on visualizations to interpret the results of queries. However, finding the right visualization for a query is a laborious and time-consuming task. We demonstrate SeeDB, a system that partially automates this task: given a query, SeeDB explores the space of all possible visualizations, and automatically identifies and recommends to the analyst those visualizations it finds to be most \\\"interesting\\\" or \\\"useful\\\". In our demonstration, conference attendees will see SeeDB in action for a variety of queries on multiple real-world datasets.","Title: Scaling Up Crowd-Sourcing to Very Large Datasets: A Case for Active Learning.\nYear: 2014\n\nAbstract: Crowd-sourcing has become a popular means of acquiring labeled data for many tasks where humans are more accurate than computers, such as image tagging, entity resolution, and sentiment analysis. However, due to the time and cost of human labor, solutions that rely solely on crowd-sourcing are often limited to small datasets (i.e., a few thousand items). This paper proposes algorithms for integrating machine learning into crowd-sourced databases in order to combine the accuracy of human labeling with the speed and cost-effectiveness of machine learning classifiers. By using active learning as our optimization strategy for labeling tasks in crowd-sourced databases, we can minimize the number of questions asked to the crowd, allowing crowd-sourced applications to scale (i.e., label much larger datasets at lower costs). Designing active learning algorithms for a crowd-sourced database poses many practical challenges: such algorithms need to be generic, scalable, and easy to use, even for practitioners who are not machine learning experts. We draw on the theory of nonparametric bootstrap to design, to the best of our knowledge, the first active learning algorithms that meet all these requirements. Our results, on 3 real-world datasets collected with Amazons Mechanical Turk, and on 15 UCI datasets, show that our methods on average ask 1--2 orders of magnitude fewer questions than the baseline, and 4.5--44× fewer than existing active learning algorithms.","Title: Rapid sampling for visualizations with ordering guarantees\nYear: 2014\n\nAbstract: Visualizations are frequently used as a means to understand trends and gather insights from datasets, but often take a long time to generate. In this paper, we focus on the problem of rapidly generating approximate visualizations while preserving crucial visual properties of interest to analysts. Our primary focus will be on sampling algorithms that preserve the visual property of ordering; our techniques will also apply to some other visual properties. For instance, our algorithms can be used to generate an approximate visualization of a bar chart very rapidly, where the comparisons between any two bars are correct. We formally show that our sampling algorithms are generally applicable and provably optimal in theory, in that they do not take more samples than necessary to generate the visualizations with ordering guarantees. They also work well in practice, correctly ordering output groups while taking orders of magnitude fewer samples and much less time than conventional sampling schemes.","Title: S-Store: a streaming NewSQL system for big velocity applications\nYear: 2014\n\nAbstract: First-generation streaming systems did not pay much attention to state management via ACID transactions (e.g., [3, 4]). S-Store is a data management system that combines OLTP transactions with stream processing. To create S-Store, we begin with H-Store, a main-memory transaction processing engine, and add primitives to support streaming. This includes triggers and transaction workflows to implement push-based processing, windows to provide a way to bound the computation, and tables with hidden state to implement scoping for proper isolation. This demo explores the benefits of this approach by showing how a naïve implementation of our benchmarks using only H-Store can yield incorrect results. We also show that by exploiting push-based semantics and our implementation of triggers, we can achieve significant improvement in transaction throughput. We demo two modern applications: (i) leaderboard maintenance for a version of \\\"American Idol\\\", and (ii) a city-scale bicycle rental scenario.","Title: DataHub: Collaborative Data Science & Dataset Version Management at Scale.\nYear: 2014\n\nAbstract: Relational databases have limited support for data collaboration, where teams collaboratively curate and analyze large datasets. Inspired by software version control systems like git, we propose (a) a dataset version control system, giving users the ability to create, branch, merge, difference and search large, divergent collections of datasets, and (b) a platform, DataHub, that gives users the ability to perform collaborative data analysis building on this version control system. We outline the challenges in providing dataset version control at scale.","Title: Knowing when you're wrong: building fast and reliable approximate query processing systems\nYear: 2014\n\nAbstract: Modern data analytics applications typically process massive amounts of data on clusters of tens, hundreds, or thousands of machines to support near-real-time decisions.The quantity of data and limitations of disk and memory bandwidth often make it infeasible to deliver answers at interactive speeds. However, it has been widely observed that many applications can tolerate some degree of inaccuracy. This is especially true for exploratory queries on data, where users are satisfied with \\\"close-enough\\\" answers if they can come quickly. A popular technique for speeding up queries at the cost of accuracy is to execute each query on a sample of data, rather than the whole dataset. To ensure that the returned result is not too inaccurate, past work on approximate query processing has used statistical techniques to estimate \\\"error bars\\\" on returned results. However, existing work in the sampling-based approximate query processing (S-AQP) community has not validated whether these techniques actually generate accurate error bars for real query workloads. In fact, we find that error bar estimation often fails on real world production workloads. Fortunately, it is possible to quickly and accurately diagnose the failure of error estimation for a query. In this paper, we show that it is possible to implement a query approximation pipeline that produces approximate answers and reliable error bars at interactive speeds.","Title: GenBase: a complex analytics genomics benchmark\nYear: 2014\n\nAbstract: This paper introduces a new benchmark designed to test database management system (DBMS) performance on a mix of data management tasks (joins, filters, etc.) and complex analytics (regression, singular value decomposition, etc.) Such mixed workloads are prevalent in a number of application areas including most science workloads and web analytics. As a specific use case, we have chosen genomics data for our benchmark and have constructed a collection of typical tasks in this domain. In addition to being representative of a mixed data management and analytics workload, this benchmark is also meant to scale to large dataset sizes and multiple nodes across a cluster. Besides presenting this benchmark, we have run it on a variety of storage systems including traditional row stores, newer column stores, Hadoop, and an array DBMS. We present performance numbers on all systems on single and multiple nodes, and show that performance differs by orders of magnitude between the various solutions. In addition, we demonstrate that most platforms have scalability issues. We also test offloading the analytics onto a coprocessor. The intent of this benchmark is to focus research interest in this area; to this end, all of our data, data generators, and scripts are available on our web site.","Title: Rethinking main memory OLTP recovery\nYear: 2014\n\nAbstract: Fine-grained, record-oriented write-ahead logging, as exemplified by systems like ARIES, has been the gold standard for relational database recovery. In this paper, we show that in modern high-throughput transaction processing systems, this is no longer the optimal way to recover a database system. In particular, as transaction throughputs get higher, ARIES-style logging starts to represent a non-trivial fraction of the overall transaction execution time. We propose a lighter weight, coarse-grained command logging technique which only records the transactions that were executed on the database. It then does recovery by starting from a transactionally consistent checkpoint and replaying the commands in the log as if they were new transactions. By avoiding the overhead of fine-grained logging of before and after images (both CPU complexity as well as substantial associated 110), command logging can yield significantly higher throughput at run-time. Recovery times for command logging are higher compared to an ARIEs-style physiological logging approach, but with the advent of high-availability techniques that can mask the outage of a recovering node, recovery speeds have become secondary in importance to run-time performance for most applications. We evaluated our approach on an implementation of TPCC in a main memory database system (VoltDB), and found that command logging can offer 1.5 x higher throughput than a main-memory optimized implementation of ARIEs-style physiological logging.","Title: GRAPHiQL: A graph intuitive query language for relational databases\nYear: 2014\n\nAbstract: Graph analytics is becoming increasingly popular, driving many important business applications from social network analysis to machine learning. Since most graph data is collected in a relational database, it seems natural to attempt to perform graph analytics within the relational environment. However, SQL, the query language for relational databases, makes it difficult to express graph analytics operations. This is because SQL requires programmers to think in terms of tables and joins, rather than the more natural representation of graphs as collections of nodes and edges. As a result, even relatively simple graph operations can require very complex SQL queries. In this paper, we present GRAPHiQL, an intuitive query language for graph analytics, which allows developers to reason in terms of nodes and edges. GRAPHiQL provides key graph constructs such as looping, recursion, and neighborhood operations. At runtime, GRAPHiQL compiles graph programs into efficient SQL queries that can run on any relational database. We demonstrate the applicability of GRAPHiQL on several applications and compare the performance of GRAPHiQL queries with those of Apache Giraph (a popular `vertex centric' graph programming language).","Title: TrajStore: An adaptive storage system for very large trajectory data sets\nYear: 2010\n\nAbstract: The rise of GPS and broadband-speed wireless devices has led to tremendous excitement about a range of applications broadly characterized as \"location based services\". Current database storage systems, however, are inadequate for manipulating the very large and dynamic spatio-temporal data sets required to support such services. Proposals in the literature either present new indices without discussing how to cluster data, potentially resulting in many disk seeks for lookups of densely packed objects, or use static quadtrees or other partitioning structures, which become rapidly suboptimal as the data or queries evolve. As a result of these performance limitations, we built TrajStore, a dynamic storage system optimized for efficiently retrieving all data in a particular spatiotemporal region. TrajStore maintains an optimal index on the data and dynamically co-locates and compresses spatially and temporally adjacent segments on disk. By letting the storage layer evolve with the index, the system adapts to incoming queries and data and is able to answer most queries via a very limited number of I/Os, even when the queries target regions containing hundreds or thousands of different trajectories. I. INTRODUCTION","Title: Database Abstractions for Managing Sensor Network Data\nYear: 2010\n\nAbstract: Sensor networking hardware, networking, and operating system software has matured to the point that the major challenges facing the field now have to do with storing, cleaning, and querying the data such networks produce. In this paper, we survey several research systems designed for managing sensor data using declarative database-like abstractions from the database community and specifically the Massachusetts Institute of Technology (MIT, Cambridge) database group. The systems we discuss are designed to help prioritize data collection in the face of intermittent bandwidth, clean and smooth data using statistical models stored inside the database, and run declarative queries over probabilistic data.","Title: SubZero: A fine-grained lineage system for scientific databases\nYear: 2013\n\nAbstract: Data lineage is a key component of provenance that helps scientists track and query relationships between input and output data. While current systems readily support lineage relationships at the file or data array level, finer-grained support at an array-cell level is impractical due to the lack of support for user defined operators and the high runtime and storage overhead to store such lineage. We interviewed scientists in several domains to identify a set of common semantics that can be leveraged to efficiently store fine-grained lineage. We use the insights to define lineage representations that efficiently capture common locality properties in the lineage data, and a set of APIs so operator developers can easily export lineage information from user defined operators. Finally, we introduce two benchmarks derived from astronomy and genomics, and show that our techniques can reduce lineage query costs by up to 10× while incuring substantially less impact on workflow runtime and storage.","Title: A Demonstration of the BigDAWG Polystore System.\nYear: 2015\n\nAbstract: This paper presents BigDAWG, a reference implementation of a new architecture for \\\"Big Data\\\" applications. Such applications not only call for large-scale analytics, but also for real-time streaming support, smaller analytics at interactive speeds, data visualization, and cross-storage-system queries. Guided by the principle that \\\"one size does not fit all\\\", we build on top of a variety of storage engines, each designed for a specialized use case. To illustrate the promise of this approach, we demonstrate its effectiveness on a hospital application using data from an intensive care unit (ICU). This complex application serves the needs of doctors and researchers and provides real-time support for streams of patient data. It showcases novel approaches for querying across multiple storage engines, data visualization, and scalable real-time analytics.","Title: S-Store: Streaming Meets Transaction Processing.\nYear: 2015\n\nAbstract: Stream processing addresses the needs of real-time applications. Transaction processing addresses the coordination and safety of short atomic computations. Heretofore, these two modes of operation existed in separate, stove-piped systems. In this work, we attempt to fuse the two computational paradigms in a single system called S-Store. In this way, S-Store can simultaneously accommodate OLTP and streaming applications. We present a simple transaction model for streams that integrates seamlessly with a traditional OLTP system, and provides both ACID and stream-oriented guarantees. We chose to build S-Store as an extension of H-Store - an open-source, in-memory, distributed OLTP database system. By implementing S-Store in this way, we can make use of the transaction processing facilities that H-Store already provides, and we can concentrate on the additional features that are needed to support streaming. Similar implementations could be done using other main-memory OLTP platforms. We show that we can actually achieve higher throughput for streaming workloads in S-Store than an equivalent deployment in H-Store alone. We also show how this can be achieved within H-Store with the addition of a modest amount of new functionality. Furthermore, we compare S-Store to two state-of-the-art streaming systems, Esper and Apache Storm, and show how S-Store can sometimes exceed their performance while at the same time providing stronger correctness guarantees.","Title: SeeDB: Efficient Data-Driven Visualization Recommendations to Support Visual Analytics.\nYear: 2015\n\nAbstract: Data analysts often build visualizations as the first step in their analytical workflow. However, when working with high-dimensional datasets, identifying visualizations that show relevant or desired trends in data can be laborious. We propose SeeDB, a visualization recommendation engine to facilitate fast visual analysis: given a subset of data to be studied, SeeDB intelligently explores the space of visualizations, evaluates promising visualizations for trends, and recommends those it deems most \"useful\" or \"interesting\". The two major obstacles in recommending interesting visualizations are (a) scale: evaluating a large number of candidate visualizations while responding within interactive time scales, and (b) utility: identifying an appropriate metric for assessing interestingness of visualizations. For the former, SeeDB introduces pruning optimizations to quickly identify high-utility visualizations and sharing optimizations to maximize sharing of computation across visualizations. For the latter, as a first step, we adopt a deviation-based metric for visualization utility, while indicating how we may be able to generalize it to other factors influencing utility. We implement SeeDB as a middleware layer that can run on top of any DBMS. Our experiments show that our framework can identify interesting visualizations with high accuracy. Our optimizations lead to multiple orders of magnitude speedup on relational row and column stores and provide recommendations at interactive time scales. Finally, we demonstrate via a user study the effectiveness of our deviation-based utility metric and the value of recommendations in supporting visual analytics.","Title: The BigDAWG Architecture.\nYear: 2016\n\nAbstract: BigDAWG is a polystore system designed to work on complex problems that naturally span across different processing or storage engines. BigDAWG provides an architecture that supports diverse database systems working with different data models, support for the competing notions of location transparency and semantic completeness via islands of information and a middleware that provides a uniform multi-island interface. In this article, we describe the current architecture of BigDAWG, its application on the MIMIC II medical dataset, and our plans for the mechanics of cross-system queries. During the presentation, we will also deliver a brief demonstration of the current version of BigDAWG.","Title: MacroBase: Analytic Monitoring for the Internet of Things.\nYear: 2016\n\nAbstract: An increasing proportion of data today is generated by automated processes, sensors, and systems---collectively, the Internet of Things (IoT). A key challenge in IoT data management and a core aspect of many IoT applications (e.g., industrial diagnostics, predictive maintenance, and equipment auditing) is in identifying and highlighting unusual and surprising data (e.g., poor driving behavior, equipment failures, physical intrusion). We call this task, which is often statistical in nature and time-sensitive, analytic monitoring. To facilitate rapid development and scalable deployment of analytic monitoring queries, we have developed MacroBase, a data analytics engine that performs analytic monitoring of IoT data streams. MacroBase implements a customizable pipeline of outlier detection, summarization, and ranking operators. For efficient and accurate execution, MacroBase implements several cross-layer optimizations across robust estimation, pattern mining, and sketching procedures, allowing order-of-magnitude speedups. As a result, MacroBase can analyze up to 1M events per second on a single core. MacroBase has already delivered meaningful analytic monitoring results in production at a medium-scale IoT startup.","Title: Refinement Driven Processing of Aggregation Constrained Queries.\nYear: 2016\n\nAbstract: Although existing database systems provide users an efficient means to select tuples based on attribute criteria, they however provide little means to select tuples based on whether they meet aggregate requirements. For instance, a requirement may be that the cardinality of the query result must be 1000 or the sum of a particular attribute must be u003c $5000. In this work, we term such queries as “Aggregation Constrained Queries” (ACQs). Aggregation constrained queries are crucial in many decision support applications to maintain a product’s competitive edge in this fast moving field of data processing. The challenge in processing ACQs is the unfamiliarity of the underlying data that results in queries being either too strict or too broad. Due to the lack of support of ACQs, users have to resort to a frustrating trial-and-error query refinement process. In this paper, we introduce and define the semantics of ACQs. We propose a refinement-based approach, called ACQUIRE, to efficiently process a range of ACQs. Lastly, in our experimental analysis we demonstrate the superiority of our technique over extensions of existing algorithms. More specifically, ACQUIRE runs up to 2 orders of magnitude faster than compared techniques while producing a 2X reduction in the amount of refinement made to the input queries.","Title: Graph analytics using vertica relational database\nYear: 2015\n\nAbstract: Graph analytics is becoming increasingly popular, with a number of new applications and systems developed in the past few years. In this paper, we study Vertica relational database as a platform for graph analytics. We show that vertex-centric graph analysis can be translated to SQL queries, typically involving table scans and joins, and that modern column-oriented databases are very well suited to running such queries. Furthermore, we show how developers can trade memory footprint for significantly reduced I/O costs in Vertica. We present an experimental evaluation of the Vertica relational database system on a variety of graph analytics, including iterative analysis, a combination of graph and relational analyses, and more complex 1-hop neighborhood graph analytics, showing that it is competitive to two popular vertex-centric graph analytics systems, namely Giraph and GraphLab.","Title: Interactive data analytics: the new frontier\nYear: 2015\n\nAbstract: Data analytics often involves data exploration, where a data set is repeatedly analyzed to understand root causes, find patterns, or extract insights. Such analysis is frequently bottlenecked by the underlying data processing system, as analysts wait for their queries to complete against a complex multilayered software stack. In this talk, I'll describe some exploratory analytics applications we've build in the MIT database group over the past few years, and will then describe some of the challenges and opportunities that arise when building more efficient data exploration systems that will allow these applications to become truly interactive, even when processing billions of data points.","Title: BigDansing: A System for Big Data Cleansing\nYear: 2015\n\nAbstract: Data cleansing approaches have usually focused on detecting and fixing errors with little attention to scaling to big datasets. This presents a serious impediment since data cleansing often involves costly computations such as enumerating pairs of tuples, handling inequality joins, and dealing with user-defined functions. In this paper, we present BigDansing, a Big Data Cleansing system to tackle efficiency, scalability, and ease-of-use issues in data cleansing. The system can run on top of most common general purpose data processing platforms, ranging from DBMSs to MapReduce-like frameworks. A user-friendly programming interface allows users to express data quality rules both declaratively and procedurally, with no requirement of being aware of the underlying distributed platform. BigDansing takes these rules into a series of transformations that enable distributed computations and several optimizations, such as shared scans and specialized joins operators. Experimental results on both synthetic and real datasets show that BigDansing outperforms existing baseline systems up to more than two orders of magnitude without sacrificing the quality provided by the repair algorithms.","Title: Decibel: The Relational Dataset Branching System.\nYear: 2016\n\nAbstract: As scientific endeavors and data analysis become increasingly collaborative, there is a need for data management systems that natively support the versioning or branching of datasets to enable concurrent analysis, cleaning, integration, manipulation, or curation of data across teams of individuals. Common practice for sharing and collaborating on datasets involves creating or storing multiple copies of the dataset, one for each stage of analysis, with no provenance information tracking the relationships between these datasets. This results not only in wasted storage, but also makes it challenging to track and integrate modifications made by different users to the same dataset. In this paper, we introduce the Relational Dataset Branching System, Decibel, a new relational storage system with built-in version control designed to address these short-comings. We present our initial design for Decibel and provide a thorough evaluation of three versioned storage engine designs that focus on efficient query processing with minimal storage overhead. We also develop an exhaustive benchmark to enable the rigorous testing of these and future versioned storage engine designs.","Title: ModelDB: a system for machine learning model management.\nYear: 2017\n\nAbstract: Building a machine learning model is an iterative process. A data scientist will build many tens to hundreds of models before arriving at one that meets some acceptance criteria (e.g. AUC cutoff, accuracy threshold). However, the current style of model building is ad-hoc and there is no practical way for a data scientist to manage models that are built over time. As a result, the data scientist must attempt to \\\"remember\\\" previously constructed models and insights obtained from them. This task is challenging for more than a handful of models and can hamper the process of sensemaking. Without a means to manage models, there is no easy way for a data scientist to answer questions such as \\\"Which models were built using an incorrect feature?\\\", \\\"Which model performed best on American customers?\\\" or \\\"How did the two top models compare?\\\" In this paper, we describe our ongoing work on ModelDB, a novel end-to-end system for the management of machine learning models. ModelDB clients automatically track machine learning models in their native environments (e.g. scikit-learn, spark.ml), the ModelDB backend introduces a common layer of abstractions to represent models and pipelines, and the ModelDB frontend allows visual exploration and analyses of models via a web-based interface.","Title: Towards large-scale data discovery: position paper.\nYear: 2016\n\nAbstract: With thousands of data sources spread across multiple databases and data lakes, modern organizations face a data discovery challenge. Analysts spend more time finding relevant data to answer the questions at hand than analyzing it. In this paper we introduce a data discovery system that facilitates locating relevant data among thousands of data sources. We represent data sources succinctly through signatures, and then create search paths that permit quick execution of a set of data discovery primitives used for finding relevant data. We have built a prototype that is being used to solve data discovery challenges of two big organizations.","Title: Amoeba: A Shape changing Storage System for Big Data.\nYear: 2016\n\nAbstract: Data partitioning significantly improves the query performance in distributed database systems. A large number of techniques have been proposed to efficiently partition a dataset for a given query workload. However, many modern analytic applications involve ad-hoc or exploratory analysis where users do not have a representative query workload upfront. Furthermore, workloads change over time as businesses evolve or as analysts gain better understanding of their data. Static workload-based data partitioning techniques are therefore not suitable for such settings. In this paper, we describe the demonstration of Amoeba, a distributed storage system which uses adaptive multi-attribute data partitioning to efficiently support ad-hoc as well as recurring queries. Amoeba applies a robust partitioning algorithm such that ad-hoc queries on all attributes have similar performance gains. Thereafter, Amoeba adaptively repartitions the data based on the observed query sequence, i.e., the system improves over time. All along Amoeba offers both adaptivity (i.e., adjustments according to workload changes) as well as robustness (i.e., avoiding performance spikes due to workload changes). We propose to demonstrate Amoeba on scenarios from an internet-of-things startup that tracks user driving patterns. We invite the audience to interactively fire fast ad-hoc queries, observe multi-dimensional adaptivity, and play with a robust/reactive knob in Amoeba. The web front end displays the layout changes, runtime costs, and compares it to Spark with both default and workload-aware partitioning.","Title: The BigDAWG polystore system and architecture\nYear: 2016\n\nAbstract: Organizations are often faced with the challenge of providing data management solutions for large, heterogenous datasets that may have different underlying data and programming models. For example, a medical dataset may have unstructured text, relational data, time series waveforms and imagery. Trying to fit such datasets in a single data management system can have adverse performance and efficiency effects. As a part of the Intel Science and Technology Center on Big Data, we are developing a polystore system designed for such problems. BigDAWG (short for the Big Data Analytics Working Group) is a polystore system designed to work on complex problems that naturally span across different processing or storage engines. BigDAWG provides an architecture that supports diverse database systems working with different data models, support for the competing notions of location transparency and semantic completeness via islands and a middleware that provides a uniform multi-island interface. Initial results from a prototype of the BigDAWG system applied to a medical dataset validate polystore concepts. In this article, we will describe polystore databases, the current BigDAWG architecture and its application on the MIMIC II medical dataset, initial performance results and our future development plans.","Title: The TileDB Array Data Storage Manager.\nYear: 2016\n\nAbstract: We present a novel storage manager for multi-dimensional arrays that arise in scientific applications, which is part of a larger scientific data management system called TileDB. In contrast to existing solutions, TileDB is optimized for both dense and sparse arrays. Its key idea is to organize array elements into ordered collections called fragments. Each fragment is dense or sparse, and groups contiguous array elements into data tiles of fixed capacity. The organization into fragments turns random writes into sequential writes, and, coupled with a novel read algorithm, leads to very efficient reads. TileDB enables parallelization via multi-threading and multi-processing, offering thread-/process-safety and atomicity via lightweight locking. We show that TileDB delivers comparable performance to the HDF5 dense array storage manager, while providing much faster random writes. We also show that TileDB offers substantially faster reads and writes than the SciDB array database system with both dense and sparse arrays. Finally, we demonstrate that TileDB is considerably faster than adaptations of the Vertica relational column-store for dense array storage management, and at least as fast for the case of sparse arrays.","Title: AdaptDB: Adaptive Partitioning for Distributed Joins.\nYear: 2017\n\nAbstract: Big data analytics often involves complex join queries over two or more tables. Such join processing is expensive in a distributed setting both because large amounts of data must be read from disk, and because of data shuffling across the network. Many techniques based on data partitioning have been proposed to reduce the amount of data that must be accessed, often focusing on finding the best partitioning scheme for a particular workload, rather than adapting to changes in the workload over time. In this paper, we present AdaptDB, an adaptive storage manager for analytical database workloads in a distributed setting. It works by partitioning datasets across a cluster and incrementally refining data partitioning as queries are run. AdaptDB introduces a novel hyper-join that avoids expensive data shuffling by identifying storage blocks of the joining tables that overlap on the join attribute, and only joining those blocks. Hyper-join performs well when each block in one table overlaps with few blocks in the other table, since that will minimize the number of blocks that have to be accessed. To minimize the number of overlapping blocks for common join queries, AdaptDB users smooth repartitioning to repartition small portions of the tables on join attributes as queries run. A prototype of AdaptDB running on top of Spark improves query performance by 2--3x on TPC-H as well as real-world dataset, versus a system that employs scans and shuffle-joins.","Title: Speedy Browsing and Sampling with NeedleTail.\nYear: 2016\n\nAbstract: Exploratory data analysis often involves repeatedly browsing small samples of records that satisfy certain ad-hoc predicates, to form and test hypotheses, identify correlations, or make inferences. Unfortunately, existing database systems are not optimized for queries with a LIMIT clause---operating instead in an all-or-nothing manner. While workload aware caching, indexing, or precomputation schemes may appear promising remedies, they do not apply in an exploratory setting where the queries are ad-hoc and unpredictable. In this paper, we propose a fast sampling engine, called NeedleTail, aimed at letting analysts browse a small sample of the query results on large datasets as quickly as possible, independent of the overall size of the result set. NeedleTail introduces density maps, a lightweight in-memory indexing structure, and a set of efficient algorithms (with desirable theoretical guarantees) to quickly locate promising blocks, trading off locality and density. In settings where the samples are used to compute aggregates, we extend techniques from the statistics literature---in particular, from survey sampling---to mitigate the bias from using our sampling algorithms. Our experimental results demonstrate that NeedleTail returns results an order of magnitude faster while occupying up to 30x less memory than existing sampling techniques.","Title: INGESTBASE: A Declarative Data Ingestion System.\nYear: 2017\n\nAbstract: Big data applications have fast arriving data that must be quickly ingested. At the same time, they have specific needs to preprocess and transform the data before it could be put to use. The current practice is to do these preparatory transformations once the data is already ingested, however, this is expensive to run and cumbersome to manage. As a result, there is a need to push data preprocessing down to the ingestion itself. In this paper, we present a declarative data ingestion system, called INGESTBASE, to allow application developers to plan and specify their data ingestion logic in a more systematic manner. We introduce the notion of ingestions plans, analogous to query plans, and present a declarative ingestion language to help developers easily build sophisticated ingestion plans. INGESTBASE provides an extensible ingestion optimizer to rewrite and optimize ingestion plans by applying rules such as operator reordering and pipelining. Finally, the INGESTBASE runtime engine runs the optimized ingestion plan in a distributed and fault-tolerant manner. Later, at query processing time, INGESTBASE supports ingestion-aware data access and interfaces with upstream query processors, such as Hadoop MapReduce and Spark, to post- process the ingested data. We demonstrate through a number of experiments that INGESTBASE: (i) is flexible enough to express a variety of ingestion techniques, (ii) incurs a low ingestion overhead, (iii) provides efficient access to the ingested data, and (iv) has much better performance, up to 6 times, than preparing data as an afterthought, via a query processor.","Title: Towards Visualization Recommendation Systems.\nYear: 2016\n\nAbstract: Data visualization is often used as the first step while performing a variety of analytical tasks. With the advent of large, high-dimensional datasets and significant interest in data science, there is a need for tools that can support rapid visual analysis. In this paper we describe our vision for a new class of visualization systems, namely visualization recommendation systems, that can automatically identify and interactively recommend visualizations relevant to an analytical task. We detail the key requirements and design considerations for a visualization recommendation system. We also identify a number of challenges in realizing this vision and describe some approaches to address them.","Title: A Demo of the Data Civilizer System.\nYear: 2017\n\nAbstract: Finding relevant data for a specific task from the numerous data sources available in any organization is a daunting task. This is not only because of the number of possible data sources where the data of interest resides, but also due to the data being scattered all over the enterprise and being typically dirty and inconsistent. In practice, data scientists are routinely reporting that the majority (more than 80%) of their effort is spent finding, cleaning, integrating, and accessing data of interest to a task at hand. We propose to demonstrate DATA CIVILIZER to ease the pain faced in analyzing data \\\"in the wild\\\". DATA CIVILIZER is an end-to-end big data management system with components for data discovery, data integration and stitching, data cleaning, and querying data from a large variety of storage engines, running in large enterprises.","Title: Generating Concise Entity Matching Rules.\nYear: 2017\n\nAbstract: Entity matching (EM) is a critical part of data integration and cleaning. In many applications, the users need to understand why two entities are considered a match, which reveals the need for interpretable and concise EM rules. We model EM rules in the form of General Boolean Formulas (GBFs) that allows arbitrary attribute matching combined by conjunctions (∨), disjunctions (∧), and negations. (¬) GBFs can generate more concise rules than traditional EM rules represented in disjunctive normal forms (DNFs). We use program synthesis, a powerful tool to automatically generate rules (or programs) that provably satisfy a high-level specification, to automatically synthesize EM rules in GBF format, given only positive and negative matching examples. In this demo, attendees will experience the following features: (1) Interpretability -- they can see and measure the conciseness of EM rules defined using GBFs; (2) Easy customization -- they can provide custom experiment parameters for various datasets, and, easily modify a rich predefined (default) synthesis grammar, using a Web interface; and (3) High performance -- they will be able to compare the generated concise rules, in terms of accuracy, with probabilistic models (e.g., machine learning methods), and hand-written EM rules provided by experts. Moreover, this system will serve as a general platform for evaluating different methods that discover EM rules, which will be released as an open-source tool on GitHub.","Title: Exploring big volume sensor data with vroom\nYear: 2017\n\nAbstract: AbstractState of the art sensors within a single autonomous vehicle (AV) can produce video and LIDAR data at rates greater than 30 GB/hour. Unsurprisingly, even small AV research teams can accumulate tens of terabytes of sensor data from multiple trips and multiple vehicles. AV practitioners would like to extract information about specific locations or specific situations for further study, but are often unable to. Queries over AV sensor data are different from generic analytics or spatial queries because they demand reasoning about fields of view as well as heavy computation to extract features from scenes. In this article and demo we present Vroom, a system for ad-hoc queries over AV sensor databases. Vroom combines domain specific properties of AV datasets with selective indexing and multi-query optimization to address challenges posed by AV sensor data.","Title: Query optimization for dynamic imputation\nYear: 2017\n\nAbstract: AbstractMissing values are common in data analysis and present a usability challenge. Users are forced to pick between removing tuples with missing values or creating a cleaned version of their data by applying a relatively expensive imputation strategy. Our system, ImputeDB, incorporates imputation into a cost-based query optimizer, performing necessary imputations on-the-fly for each query. This allows users to immediately explore their data, while the system picks the optimal placement of imputation operations. We evaluate this approach on three real-world survey-based datasets. Our experiments show that our query plans execute between 10 and 140 times faster than first imputing the base tables. Furthermore, we show that the query results from on-the-fly imputation differ from the traditional base-table imputation approach by 0--8%. Finally, we show that while dropping tuples with missing values that fail query constraints discards 6--78% of the data, on-the-fly imputation loses only 0--21%.","Title: A robust partitioning scheme for ad-hoc query workloads.\nYear: 2017\n\nAbstract: Data partitioning is crucial to improving query performance several workload-based partitioning techniques have been proposed in database literature. However, many modern analytic applications involve ad-hoc or exploratory analysis where users do not have a representative query workload a priori. Static workload-based data partitioning techniques are therefore not suitable for such settings. In this paper, we propose Amoeba, a distributed storage system that uses adaptive multi-attribute data partitioning to efficiently support ad-hoc as well as recurring queries. Amoeba requires zero set-up and tuning effort, allowing analysts to get the benefits of partitioning without requiring an upfront query workload. The key idea is to build and maintain a partitioning tree on top of the dataset. The partitioning tree allows us to answer queries with predicates by reading a subset of the data. The initial partitioning tree is created without requiring an upfront query workload and Amoeba adapts it over time by incrementally modifying subtrees based on user queries using repartitioning. A prototype of Amoeba running on top of Apache Spark improves query performance by up to 7x over full scans and up to 2x over range-based partitioning techniques on TPC-H as well as a real-world workload.","Title: Bigdawg Version 0.1\nYear: 2017\n\nAbstract: A polystore system is a database management system composed of integrated heterogeneous database engines and multiple programming languages. By matching data to the storage engine best suited to its needs, complex analytics run faster and flexible storage choices helps improve data organization. BigDAWG (Big Data Working Group) is our prototype implementation of a polystore system. In this paper, we describe the current BigDAWG software release which supports PostgreSQL, Accumulo and SciDB. We describe the overall architecture, API and initial results of applying BigDAWG to the MIMIC II medical dataset.","Title: Weld: Rethinking the Interface Between Data-Intensive Applications.\nYear: 2017\n\nAbstract: Data analytics applications combine multiple functions from different libraries and frameworks. Even when each function is optimized in isolation, the performance of the combined application can be an order of magnitude below hardware limits due to extensive data movement across these functions. To address this problem, we propose Weld, a new interface between data-intensive libraries that can optimize across disjoint libraries and functions. Weld exposes a lazily-evaluated API where diverse functions can submit their computations in a simple but general intermediate representation that captures their data-parallel structure. It then optimizes data movement across these functions and emits efficient code for diverse hardware. Weld can be integrated into existing frameworks such as Spark, TensorFlow, Pandas and NumPy without changing their user-facing APIs. We demonstrate that Weld can speed up applications using these frameworks by up to 29x.","Title: Entity Consolidation: The Golden Record Problem.\nYear: 2017\n\nAbstract: Four key processes in data integration are: data preparation (i.e., extracting, transforming, and cleaning data), schema integration (i.e., identifying attribute correspondences), entity resolution (i.e., finding clusters of records that represent the same entity) and entity consolidation (i.e., merging each cluster into a u0027golden recordu0027, which contains the canonical value for each attribute). In real-world scenarios, Master Data Management (MDM) is often employed to perform the last two steps using a u0027match-mergeu0027 module, which is driven by a collection of user-written match and merge rules. However, it is well understood that such solutions often fail to scale to the sizes and complexity of problems currently being addressed. Scalable solutions to entity resolution have been previously developed to generate a collection of clusters of records representing the same entity. In this paper, we propose a scalable entity consolidation algorithm to merge these clusters into u0027golden recordsu0027. We first automatically generate matching rules from the clusters and then group these rules into sets with common characteristics to cut down on the number which must be verified by a human. Next, for the human-approved rule groups, we apply them to merge the duplicate attribute values in the clusters. Finally, we employ existing truth discovery methods, such as majority consensus (MC), to resolve remaining conflicts in the clusters. We applied our methods on three real-world datasets. In a dataset with 31,023 clusters and 80,451 duplicate records, 72,239 matching rules were generated. By having a human con rm only 100 algorithm-generated rule groups, we achieved a recall of 75% and a precision of 98% for merging duplicate attribute values. When we invoked our algorithm prior to running MC, we improved the precision of golden record construction by 40%.","Title: Efficient Top-K Query Processing on Massively Parallel Hardware.\nYear: 2018\n\nAbstract: A common operation in many data analytics workloads is to find the top-k items, i.e., the largest or smallest operations according to some sort order (implemented via LIMIT or ORDER BY expressions in SQL). A naive implementation of top-k is to sort all of the items and then return the first k, but this does much more work than needed. Although efficient implementations for top-k have been explored on traditional multi-core processors, there has been no prior systematic study of top-k implementations on GPUs, despite open requests for such implementations in GPU-based frameworks like TensorFlow and ArrayFire. In this work, we present several top-k algorithms for GPUs, including a new algorithm based on bitonic sort called bitonic top-k. The bitonic top-k algorithm is up to a factor of \\new15x faster than sort and 4x faster than a variety of other possible implementations for values of k up to 256. We also develop a cost model to predict the performance of several of our algorithms, and show that it accurately predicts actual performance on modern GPUs.","Title: MISTIQUE: A System to Store and Query Model Intermediates for Model Diagnosis.\nYear: 2018\n\nAbstract: Model diagnosis is the process of analyzing machine learning (ML) model performance to identify where the model works well and where it doesn't. It is a key part of the modeling process and helps ML developers iteratively improve model accuracy. Often, model diagnosis is performed by analyzing different datasets or intermediates associated with the model such as the input data and hidden representations learned by the model (e.g., [4, 24, 39,]). The bottleneck in fast model diagnosis is the creation and storage of model intermediates. Storing these intermediates requires tens to hundreds of GB of storage whereas re-running the model for each diagnostic query slows down model diagnosis. To address this bottleneck, we propose a system called MISTIQUE that can work with traditional ML pipelines as well as deep neural networks to efficiently capture, store, and query model intermediates for diagnosis. For each diagnostic query, MISTIQUE intelligently chooses whether to re-run the model or read a previously stored intermediate. For intermediates that are stored in MISTIQUE, we propose a range of optimizations to reduce storage footprint including quantization, summarization, and data de-duplication. We evaluate our techniques on a range of real-world ML models in scikit-learn and Tensorflow. We demonstrate that our optimizations reduce storage by up to 110X for traditional ML pipelines and up to 6X for deep neural networks. Furthermore, by using MISTIQUE, we can speed up diagnostic queries on traditional ML pipelines by up to 390X and 210X on deep neural networks.","Title: Evaluating end-to-end optimization for data analytics applications in weld\nYear: 2018\n\nAbstract: AbstractModern analytics applications use a diverse mix of libraries and functions. Unfortunately, there is no optimization across these libraries, resulting in performance penalties as high as an order of magnitude in many applications. To address this problem, we proposed Weld, a common runtime for existing data analytics libraries that performs key physical optimizations such as pipelining under existing, imperative library APIs. In this work, we further develop the Weld vision by designing an automatic adaptive optimizer for Weld applications, and evaluating its impact on realistic data science workloads. Our optimizer eliminates multiple forms of overhead that arise when composing imperative libraries like Pandas and NumPy, and uses lightweight measurements to make data-dependent decisions at run-time in ad-hoc workloads where no statistics are available, with sub-second overhead. We also evaluate which optimizations have the largest impact in practice and whether Weld can be integrated into libraries incrementally. Our results are promising: using our optimizer, Weld accelerates data science workloads by up to 23X on one thread and 80X on eight threads, and its adaptive optimizations provide up to a 3.75X speedup over rule-based optimization. Moreover, Weld provides benefits if even just 4--5 operators in a library are ported to use it. Our results show that common runtime designs like Weld may be a viable approach to accelerate analytics.","Title: Smallify: Learning Network Size while Training.\nYear: 2018\n\nAbstract: As neural networks become widely deployed in different applications and on different hardware, it has become increasingly important to optimize inference time and model size along with model accuracy. Most current techniques optimize model size, model accuracy and inference time in different stages, resulting in suboptimal results and computational inefficiency. In this work, we propose a new technique called Smallify that optimizes all three of these metrics at the same time. Specifically we present a new method to simultaneously optimize network size and model performance by neuron-level pruning during training. Neuron-level pruning not only produces much smaller networks but also produces dense weight matrices that are amenable to efficient inference. By applying our technique to convolutional as well as fully connected models, we show that Smallify can reduce network size by 35X with a 6X improvement in inference time with similar accuracy as models found by traditional training techniques.","Title: Aurum: A Data Discovery System\nYear: 2018\n\nAbstract: Organizations face a data discovery problem when their analysts spend more time looking for relevant data than analyzing it. This problem has become commonplace in modern organizations as: i) data is stored across multiple storage systems, from databases to data lakes, to the cloud; ii) data scientists do not operate within the limits of well-defined schemas or a small number of data sources—instead, to answer complex questions they must access data spread across thousands of data sources. To address this problem, we capture relationships between datasets in an enterprise knowledge graph (EKG), which helps users to navigate among disparate sources. The contribution of this paper is AURUM, a system to build, maintain and query the EKG. To build the EKG, we introduce a Two-step process which scales to large datasets and requires only one-pass over the data, avoiding overloading the source systems. To maintain the EKG without re-reading all data every time, we introduce a resource-efficient sampling signature (RESS) method which works by only using a small sample of the data. Finally, to query the EKG, we introduce a collection of composable primitives, thus allowing users to define many different types of discovery queries. We describe our experience using AURUM in three corporate scenarios and do a performance evaluation of each component.","Title: Seeping Semantics: Linking Datasets Using Word Embeddings for Data Discovery\nYear: 2018\n\nAbstract: Employees that spend more time finding relevant data than analyzing it suffer from a data discovery problem. The large volume of data in enterprises, and sometimes the lack of knowledge of the schemas aggravates this problem. Similar to how we navigate the Web, we propose to identify semantic links that assist analysts in their discovery tasks. These links relate tables to each other, to facilitate navigating the schemas. They also relate data to external data sources, such as ontologies and dictionaries, to help explain the schema meaning. We materialize the links in an enterprise knowledge graph, where they become available to analysts. The main challenge is how to find pairs of objects that are semantically related. We propose SEMPROP, a DAG of different components that find links based on syntactic and semantic similarities. SEMPROP is commanded by a semantic matcher which leverages word embeddings to find objects that are semantically related. We introduce coherent group, a technique to combine word embeddings that works better than other state of the art combination alternatives. We implement SEMPROP as part of Aurum, a data discovery system we are building, and conduct user studies, real deployments and a quantitative evaluation to understand the benefits of links for data discovery tasks, as well as the benefits of SEMPROP and coherent groups to find those links.","Title: STAR: Scaling Transactions through Asymmetrical Replication.\nYear: 2018\n\nAbstract: In this paper, we present STAR, a new distributed and replicated in-memory database. By employing a single-node non-partitioned architecture for some replicas and a partitioned architecture for other replicas, STAR is able to efficiently run both highly partitionable workloads and workloads that involve cross-partition transactions. The key idea is a new phase-switching algorithm where the execution of single-partition and cross-partition transactions are separated. In the partitioned phase, single-partition transactions are run on multiple machines in parallel to exploit more concurrency. In the single-master phase, mastership for the entire database is switched to a designated coordinator node, which can execute these transactions without the use of expensive coordination protocols like two-phase commit. Because the coordinator node has a full copy of the database, this phase-switching can be done at negligible cost. Our experiments on two popular benchmarks (YCSB and TPC-C) show that high availability via replication can coexist with fast serializable transaction execution in distributed in-memory databases, with STAR outperforming systems that employ conventional concurrency control and replication algorithms by up to one order of magnitude.","Title: MacroBase: Prioritizing Attention in Fast Data.\nYear: 2018\n\nAbstract: As data volumes continue to rise, manual inspection is becoming increasingly untenable. In response, we present MacroBase, a data analytics engine that prioritizes end-user attention in high-volume fast data streams. MacroBase enables efficient, accurate, and modular analyses that highlight and aggregate important and unusual behavior, acting as a search engine for fast data. MacroBase is able to deliver order-of-magnitude speedups over alternatives by optimizing the combination of explanation (i.e., feature selection) and classification tasks and by leveraging a new reservoir sampler and heavy-hitters sketch specialized for fast data streams. As a result, MacroBase delivers accurate results at speeds of up to 2M events per second per query on a single core. The system has delivered meaningful results in production, including at a telematics company monitoring hundreds of thousands of vehicles.","Title: SWIFT: Mining Representative Patterns from Large Event Streams.\nYear: 2018\n\nAbstract: Event streams generated by smart devices common in modern Internet of Things applications must be continuously mined to monitor the behavior of the underlying system. In this work, we propose a stream pattern mining system for supporting online IoT applications. First, to solve the pattern explosion problem of existing stream pattern mining strategies, we now design pattern semantics that continuously produce a compact set of patterns that max-imumly compresses the dynamic data streams, called MDL-based Representative Patterns (MRP). We then design a one-pass SWIFT approach that continuously mines the up-to-date MRP pattern set for each stream window upon the arrival or expiration of individual events. We show that SWIFT is guaranteed to select the update operation for each individual incoming event that leads to the most compact encoding of the sequence in the current window. We further enhance SWIFT to support batch updates, called B-SWIFT. B-SWIFT adopts a lazy update strategy that guarantees that only the minimal number of operations are conducted to process an incoming event batch for MRP pattern mining. Evaluation by our industry lighting lab collaborator demonstrates that SWIFT successfully solves their use cases and finds more representative patterns than the alternative approaches adapting the state-of-the-art static representative pattern mining methods. Our experimental study confirms that SWIFT outperforms the best existing method up to 50% in the compactness of produced pattern encodings, while providing a 4 orders of magnitude speedup.","Title: Transactional consistency and automatic management in an application data cache\nYear: 2010\n\nAbstract: Distributed in-memory application data caches like memcached are a popular solution for scaling database-driven web sites. These systems are easy to add to existing deployments, and increase performance significantly by reducing load on both the database and application servers. Unfortunately, such caches do not integrate well with the database or the application. They cannot maintain transactional consistency across the entire system, violating the isolation properties of the underlying database. They leave the application responsible for locating data in the cache and keeping it up to date, a frequent source of application complexity and programming errors. Addressing both of these problems, we introduce a transactional cache, TxCache, with a simple programming model. TxCache ensures that any data seen within a transaction, whether it comes from the cache or the database, reflects a slightly stale but consistent snapshot of the database. TxCache makes it easy to add caching to an application by simply designating functions as cacheable; it automatically caches their results, and invalidates the cached data as the underlying database changes. Our experiments found that adding TxCache increased the throughput of a web application by up to 5.2×, only slightly less than a non-transactional cache, showing that consistency does not have to come at the price of performance.","Title: BigDAWG Polystore Release and Demonstration.\nYear: 2017\n\nAbstract: The Intel Science and Technology Center for Big Data is developing a reference implementation of a Polystore database. The BigDAWG (Big Data Working Group) system supports many sizes of database engines, multiple programming languages and complex analytics for a variety of workloads. Our recent efforts include application of BigDAWG to an ocean metagenomics problem and containerization of BigDAWG. We intend to release an open source BigDAWG v1.0 in the Spring of 2017. In this article, we will demonstrate a number of polystore applications developed with oceanographic researchers at MIT and describe our forthcoming open source release of the BigDAWG system.","Title: BigDAWG version 0.1\nYear: 2017\n\nAbstract: A polystore system is a database management system composed of integrated heterogeneous database engines and multiple programming languages. By matching data to the storage engine best suited to its needs, complex analytics run faster and flexible storage choices helps improve data organization. BigDAWG (Big Data Working Group) is our prototype implementation of a polystore system. In this paper, we describe the current BigDAWG software release which supports PostgreSQL, Accumulo and SciDB. We describe the overall architecture, API and initial results of applying BigDAWG to the MIMIC II medical dataset.","Title: Unsupervised String Transformation Learning for Entity Consolidation\nYear: 2019\n\nAbstract: Data integration has been a long-standing challenge in data management with many applications. A key step in data integration is entity consolidation. It takes a collection of clusters of duplicate records as input and produces a single \"golden record\" for each cluster, which contains the canonical value for each attribute. Truth discovery and data fusion methods as well as Master Data Management (MDM) systems can be used for entity consolidation. However, to achieve better results, the variant values (i.e., values that are logically the same with different formats) in the clusters need to be consolidated before applying these methods. For this purpose, we propose a data-driven method to standardize the variant values based on two observations: (1) the variant values usually can be transformed to the same representation (e.g., \"Mary Lee\" and \"Lee, Mary\") and (2) the same transformation often appears repeatedly across different clusters (e.g., transpose the first and last name). Our approach first uses an unsupervised method to generate groups of value pairs that can be transformed in the same way. Then the groups are presented to a human for verification and the approved ones are used to standardize the data. In a real-world dataset with 17,497 records, our method achieved 75% recall and 99.5% precision in standardizing variant values by asking a human 100 yes/no questions, which completely outperformed a state of the art data wrangling tool.","Title: Termite: a system for tunneling through heterogeneous data\nYear: 2019\n\nAbstract: Data-driven analysis is important in virtually every modern organization. Yet, most data is underutilized because it remains locked in silos inside of organizations; large organizations have thousands of databases, and billions of files that are not integrated together in a single, queryable repository. Despite 40+ years of continuous effort by the database community, data integration still remains an open challenge.\n\nIn this paper, we advocate a different approach: rather than trying to infer a common schema, we aim to find another common representation for diverse, heterogeneous data. Specifically, we argue for an embedding (i.e., a vector space) in which all entities, rows, columns, and paragraphs are represented as points. In the embedding, the distance between points indicates their degree of relatedness. We present Termite, a prototype we have built to learn the best embedding from the data. Because the best representation is learned, this allows Termite to avoid much of the human effort associated with traditional data integration tasks. On top of Termite, we have implemented a Termite-Join operator, which allows people to identify related concepts, even when these are stored in databases with different schemas and in unstructured data such as text files, webpages, etc. Finally, we show preliminary evaluation results of our prototype via a user study, and describe a list of future directions we have identified.","Title: SysML: The New Frontier of Machine Learning Systems.\nYear: 2019\n\nAbstract: Machine learning (ML) techniques are enjoying rapidly increasing adoption. However, designing and implementing the systems that support ML models in real-world deployments remains a significant obstacle, in large part due to the radically different development and deployment profile of modern ML methods, and the range of practical concerns that come with broader adoption. We propose to foster a new systems machine learning research community at the intersection of the traditional systems and ML communities, focused on topics such as hardware systems for ML, software systems for ML, and ML optimized for metrics beyond predictive accuracy. To do this, we describe a new conference, SysML, that explicitly targets research at the intersection of systems and machine learning with a program committee split evenly between experts in systems and ML, and an explicit focus on topics at the intersection of the two.","Title: SCAR: Strong Consistency using Asynchronous Replication with Minimal Coordination.\nYear: 2019\n\nAbstract: Data replication is crucial in modern distributed systems as a means to provide high availability. Many techniques have been proposed to utilize replicas to improve a systemu0027s performance, often requiring expensive coordination or sacrificing consistency. In this paper, we present SCAR, a new distributed and replicated in-memory database that allows serializable transactions to read from backup replicas with minimal coordination. SCAR works by assigning logical timestamps to database records so that a transaction can safely read from a backup replica without coordinating with the primary replica, because the records cannot be changed up to a certain logical time. In addition, we propose two optimization techniques, timestamp synchronization and parallel locking and validation, to further reduce coordination. We show that SCAR outperforms systems with conventional concurrency control algorithms and replication strategies by up to a factor of 2 on three popular benchmarks. We also demonstrate that SCAR achieves higher throughput by running under reduced isolation levels and detects concurrency anomalies in real time.","Title: Deductive Optimization of Relational Data Storage.\nYear: 2019\n\nAbstract: Optimizing the physical data storage and retrieval of data are two key database management problems. In this paper, we propose a language that can express both a relational query and the layout of its data. Our language can express a wide range of physical database layouts, going well beyond the row- and column-based methods that are widely used in database management systems. We use deductive program synthesis to turn a high-level relational representation of a database query into a highly optimized low-level implementation which operates on a specialized layout of the dataset. We build an optimizing compiler for this language and conduct experiments using a popular database benchmark, which shows that the performance of our specialized queries is better than a state-of-the-art in memory compiled database system while achieving an order-of-magnitude reduction in memory use.","Title: Lazo: A Cardinality-Based Method for Coupled Estimation of Jaccard Similarity and Containment\nYear: 2019\n\nAbstract: Data analysts often need to find datasets that are similar (i.e., have high overlap) or that are subsets of one another (i.e., one contains the other). Exactly computing such relationships is expensive because it entails an all-pairs comparison between all values in all datasets, an O(n2) operation. Fortunately, it is possible to obtain approximate solutions much faster, using locality sensitive hashing (LSH). Unfortunately, LSH does not lend itself naturally to compute containment, and only returns results with a similarity beyond a pre-defined threshold; we want to know the specific similarity and containment score. The main contribution of this paper is LAZO, a method to simultaneously estimate both the similarity and containment of datasets, based on a redefinition of Jaccard similarity which takes into account the cardinality of each set. In addition, we show how to use the method to improve the quality of the original JS and JC estimates. Last, we implement LAZO as a new indexing structure that has these additional properties: i) it returns numerical scores to indicate the degree of similarity and containment between each candidate and the query—instead of only returning the candidate set; ii) it permits to query for a specific threshold on-the-fly, as opposed to LSH indexes that need to be configured with a pre-defined threshold a priori; iii) it works in a data-oblivious way, so it can be incrementally maintained. We evaluate LAZO on real-world datasets and show its ability to estimate containment and similarity better and faster than existing methods.","Title: Raha: A Configuration-Free Error Detection System\nYear: 2019\n\nAbstract: Detecting erroneous values is a key step in data cleaning. Error detection algorithms usually require a user to provide input configurations in the form of rules or statistical parameters. However, providing a complete, yet correct, set of configurations for each new dataset is not trivial, as the user has to know about both the dataset and the error detection algorithms upfront. In this paper, we present Raha, a new configuration-free error detection system. By generating a limited number of configurations for error detection algorithms that cover various types of data errors, we can generate an expressive feature vector for each tuple value. Leveraging these feature vectors, we propose a novel sampling and classification scheme that effectively chooses the most representative values for training. Furthermore, our system can exploit historical data to filter out irrelevant error detection algorithms and configurations. In our experiments, Raha outperforms the state-of-the-art error detection techniques with no more than 20 labeled tuples on each dataset.","Title: Efficient discovery of sequence outlier patterns\nYear: 2019\n\nAbstract: Modern Internet of Things (IoT) applications generate massive amounts of time-stamped data, much of it in the form of discrete, symbolic sequences. In this work, we present a new system called TOP that de<u>T</u>ects <u>O</u>utlier <u>P</u>atterns from these sequences. To solve the fundamental limitation of existing pattern mining semantics that miss outlier patterns hidden inside of larger frequent patterns, TOP offers new pattern semantics based on contextual patterns that distinguish the independent occurrence of a pattern from its occurrence as part of its super-pattern. We present efficient algorithms for the mining of this new class of contextual patterns. In particular, in contrast to the bottom-up strategy for state-of-the-art pattern mining techniques, our top-down Reduce strategy piggy backs pattern detection with the detection of the context in which a pattern occurs. Our approach achieves linear time complexity in the length of the input sequence. Effective optimization techniques such as context-driven search space pruning and inverted index-based outlier pattern detection are also proposed to further speed up contextual pattern mining. Our experimental evaluation demonstrates the effectiveness of TOP at capturing meaningful outlier patterns in several real-world IoT use cases. We also demonstrate the efficiency of TOP, showing it to be up to 2 orders of magnitude faster than adapting state-of-the-art mining to produce this new class of contextual outlier patterns, allowing us to scale outlier pattern mining to large sequence datasets.","Title: Technical Report: Optimizing Human Involvement for Entity Matching and Consolidation.\nYear: 2019\n\nAbstract: An end-to-end data integration system requires human feedback in several phases, including collecting training data for entity matching, debugging the resulting clusters, confirming transformations applied on these clusters for data standardization, and finally, reducing each cluster to a single, canonical representation (or \"golden record\"). The traditional wisdom is to sequentially apply the human feedback, obtained by asking specific questions, within some budget in each phase. However, these questions are highly correlated; the answer to one can influence the outcome of any of the phases of the pipeline. Hence, interleaving them has the potential to offer significant benefits. In this paper, we propose a human-in-the-loop framework that interleaves different types of questions to optimize human involvement. We propose benefit models to measure the quality improvement from asking a question, and cost models to measure the human time it takes to answer a question. We develop a question scheduling framework that judiciously selects questions to maximize the accuracy of the final golden records. Experimental results on three real-world datasets show that our holistic method significantly improves the quality of golden records from 70% to 90%, compared with the state-of-the-art approaches.","Title: Asynchronous Prefix Recoverability for Fast Distributed Stores\nYear: 2021\n\nAbstract: ABSTRACTAccessing and updating data sharded across distributed machines safely and speedily in the face of failures remains a challenging problem. Most prominently, applications that share state across different nodes want their writes to quickly become visible to others, without giving up recoverability guarantees in case a failure occurs. Current solutions of a fast cache backed by storage cannot support this use case easily. In this work, we design a distributed protocol, called Distributed Prefix Recovery (DPR) that builds on top of a sharded cache-store architecture with single-key operations, to provide cross-shard recoverability guarantees. With DPR, many clients can read and update shared state at sub-millisecond latency, while receiving periodic prefix durability guarantees. On failure, DPR quickly restores the system to a prefix-consistent state with a novel non-blocking rollback scheme. We added DPR to a key-value store (FASTER) and cache (Redis) and show that we can get high throughput and low latency similar to in-memory systems, while lazily providing durability guarantees similar to persistent stores.","Title: ELITE: Robust Deep Anomaly Detection with Meta Gradient\nYear: 2021\n\nAbstract: ABSTRACTDeep Learning techniques have been widely used in detecting anomalies from complex data. Most of these techniques are either unsupervised or semi-supervised because of a lack of a large number of labeled anomalies. However, they typically rely on a clean training data not polluted by anomalies to learn the distribution of the normal data. Otherwise, the learned distribution tends to be distorted and hence ineffective in distinguishing between normal and abnormal data. To solve this problem, we propose a novel approach called ELITE that uses a small number of labeled examples to infer the anomalies hidden in the training samples. It then turns these anomalies into useful signals that help to better detect anomalies from user data. Unlike the classical semi-supervised classification strategy which uses labeled examples as training data, ELITE uses them as validation set. It leverages the gradient of the validation loss to predict if one training sample is abnormal. The intuition is that correctly identifying the hidden anomalies could produce a better deep anomaly model with reduced validation loss. Our experiments on public benchmark datasets show that ELITE achieves up to 30% improvement in ROC AUC comparing to the state-of-the-art, yet robust to polluted training data.","Title: LANCET: labeling complex data at scale\nYear: 2021\n\nAbstract: AbstractCutting-edge machine learning techniques often require millions of labeled data objects to train a robust model. Because relying on humans to supply such a huge number of labels is rarely practical, automated methods for label generation are needed. Unfortunately, critical challenges in auto-labeling remain unsolved, including the following research questions: (1) which objects to ask humans to label, (2) how to automatically propagate labels to other objects, and (3) when to stop labeling. These three questions are not only each challenging in their own right, but they also correspond to tightly interdependent problems. Yet existing techniques provide at best isolated solutions to a subset of these challenges. In this work, we propose the first approach, called LANCET, that successfully addresses all three challenges in an integrated framework. LANCET is based on a theoretical foundation characterizing the properties that the labeled dataset must satisfy to train an effective prediction model, namely the Covariate-shift and the Continuity conditions. First, guided by the Covariate-shift condition, LANCET maps raw input data into a semantic feature space, where an unlabeled object is expected to share the same label with its near-by labeled neighbor. Next, guided by the Continuity condition, LANCET selects objects for labeling, aiming to ensure that unlabeled objects always have some sufficiently close labeled neighbors. These two strategies jointly maximize the accuracy of the automatically produced labels and the prediction accuracy of the machine learning models trained on these labels. Lastly, LANCET uses a distribution matching network to verify whether both the Covariate-shift and Continuity conditions hold, in which case it would be safe to terminate the labeling process. Our experiments on diverse public data sets demonstrate that LANCET consistently outperforms the state-of-the-art methods from Snuba to GOGGLES and other baselines by a large margin - up to 30 percentage points increase in accuracy.","Title: ATLANTIC: making database differentially private and faster with accuracy guarantee\nYear: 2021\n\nAbstract: AbstractDifferential privacy promises to enable data sharing and general data analytics while protecting individual privacy. Because the private data is often stored in the form of relational database that supports SQL queries, making SQL-based analytics differentially private is thus critical. However, the existing SQL-based differentially private systems either only focus on specific type of SQL queries such as COUNT or substantially modify the database engine, thus obstructing adoption in practice. Worse yet, these systems often do not guarantee the desired accuracy by the applications. In this demonstration, using the driving trace workload from Cambridge Mobile Telematics (CMT), we show that our ATLANTIC system, as a database middleware, enforces differential privacy for real-world SQL queries with provable accuracy guarantees and is compatible with existing databases. Moreover, using a sampling-based technique, ATLANTIC significantly speeds up the query execution, yet effectively amplifying the privacy guarantee.","Title: Inferring high-resolution traffic accident risk maps based on satellite imagery and GPS trajectories.\nYear: 2021\n\nAbstract: Traffic accidents cost about 3% of the world's GDP and are the leading cause of death in children and young adults. Accident risk maps are useful tools to monitor and mitigate accident risk. We present a technique to generate high-resolution (5 meters) accident risk maps. At this high resolution, accidents are sparse and risk estimation is limited by bias-variance trade-off. Prior accident risk maps either estimate low-resolution maps that are of low utility (high bias), or they use frequency-based estimation techniques that inaccurately predict where accidents actually happen (high variance). To improve this trade-off, we use an end-to-end deep architecture that can input satellite imagery, GPS trajectories, road maps and the history of accidents. Our evaluation on four metropolitan areas in the US with a total area of 7,488 km2 shows that our technique outperforms prior work in terms of resolution and accuracy.","Title: Nonintrusive Measurements for Detecting Progressive Equipment Faults\nYear: 2022\n\nAbstract: The gradual environmental degradation of materials can lead to corrosion and mechanical failures of electrical loads. Vibration and corrosion both contribute to the failure of electrical connections and conductors, and electrical arcs destroy materials in ways that enhance the opportunities for further damage. These failures lead to loss of system capability and the possibility of electrical fires. The signatures of these impending electrical failures, which may occur over weeks or months, can be detected in many systems through nonintrusive electrical monitoring. This article demonstrates techniques for decoding the type of electrical signatures that lead to progressive failure. Example applications of these techniques are illustrated with observations of the degradation and failure of copper-sheathed jacket water (JW) heaters aboard a United States Coast Guard (USCG) vessel. Electrical, material, and vibration analysis are presented to demonstrate the basis for diagnostic electrical signatures.","Title: OTIF: Efficient Tracker Pre-processing over Large Video Datasets\nYear: 2022\n\nAbstract: Performing analytics tasks over large-scale video datasets is increasingly common in a wide range of applications, from traffic planning to sports analytics. These tasks generally involve object detection and tracking operations that require pre-processing the video through expensive machine learning models. To address this cost, several video query optimizers have recently been proposed. Broadly, these methods trade large reductions in pre-processing cost for increases in query execution cost: during query execution, they apply query-specific machine learning operations over portions of the video dataset. Although video query optimizers reduce the overall cost of executing a single query over large video datasets compared to naive object tracking methods, executing several queries over the same video remains cost-prohibitive; moreover, the high per-query latency makes these systems unsuitable for exploratory analytics where fast response times are crucial. In this paper, we present OTIF, a video pre-processor that efficiently extracts all object tracks from large-scale video datasets. By integrating several optimizations under a joint parameter tuning framework, OTIF is able to extract all object tracks from video as fast as existing video query optimizers can execute just one single query. In contrast to the outputs of video query optimizers, OTIF's outputs are general-purpose object tracks that can be used to execute many queries with sub-second latencies. We compare OTIF against three recent video query optimizers, as well as several general-purpose object detection and tracking techniques, and find that, across multiple datasets, OTIF provides a 6x to 25x average reduction in the overall cost to execute five queries over the same video.","Title: Tile-based Lightweight Integer Compression in GPU\nYear: 2022\n\nAbstract: GPUs are increasingly used for high-performance and interactive data analytics workloads due to their capability to accelerate computation using massive parallelism. A key constraint of GPU-based data analytics today is the limited memory capacity in GPU devices. Data compression is a powerful technique that can mitigate the capacity limitation in two ways: (1) fitting more data into GPU memory and (2) speeding up data transfer between CPU and GPU. However, compression schemes for GPU today are still limited in compression ratio and/or decompression speed. We identify two limiting factors of existing approaches. First, existing decompression solutions require multiple passes of scanning the global memory to decode layers of compression schemes, incurring significant memory traffic and hurting performance. We present the tile-based decompression model to decompress encoded data in a single pass over global memory and inline with query execution. Second, we develop an efficient implementation of bit-packing-based compression schemes and their optimization techniques in the context of GPU. Our evaluation shows that our schemes can achieve similar compression rates to the best state-of-the-art compression schemes in GPU (i.e., nvCOMP) while being 2.2x and 2.6x faster in decompression speed and query running time.","Title: Replicated Layout for In-Memory Database Systems\nYear: 2021\n\nAbstract: Scanning and filtering are the foundations of analytical database systems. Modern DBMSs employ a variety of techniques to partition and layout data to improve the performance of these operations. To accelerate query performance, systems tune data layout to reduce the cost of accessing and processing data. However, these layouts optimize for the average query, and with heterogeneous data access patterns in parts of the data, their performance degrades. To mitigate this, we present CopyRight, a layout-aware partial replication engine that replicates parts of the data differently and lays out each replica differently to maximize the overall query performance. Across a range of real-world query workloads, CopyRight is able to achieve 1.1X to 7.9X faster performance than the best non-replicated layout with 0.25X space overhead. When compared to full table replication with 100% overhead, CopyRight attains the same or up to 5.2X speedup with 25% space overhead."],"string":"[\n \"Title: A continuous query system for dynamic route planning\\nYear: 2011\\n\\nAbstract: In this paper, we address the problem of answering continuous route planning queries over a road network, in the presence of updates to the delay (cost) estimates of links. A simple approach to this problem would be to recompute the best path for all queries on arrival of every delay update. However, such a naive approach scales poorly when there are many users who have requested routes in the system. Instead, we propose two new classes of approximate techniques - K-paths and proximity measures to substantially speed up processing of the set of designated routes specified by continuous route planning queries in the face of incoming traffic delay updates. Our techniques work through a combination of pre-computation of likely good paths and by avoiding complete recalculations on every delay update, instead only sending the user new routes when delays change significantly. Based on an experimental evaluation with 7,000 drives from real taxi cabs, we found that the routes delivered by our techniques are within 5% of the best shortest path and have run times an order of magnitude or less compared to a naive approach.\",\n \"Title: OLTP through the looking glass, and what we found there\\nYear: 2008\\n\\nAbstract: Online Transaction Processing (OLTP) databases include a suite of features - disk-resident B-trees and heap files, locking-based concurrency control, support for multi-threading - that were optimized for computer technology of the late 1970's. Advances in modern processors, memories, and networks mean that today's computers are vastly different from those of 30 years ago, such that many OLTP databases will now fit in main memory, and most OLTP transactions can be processed in milliseconds or less. Yet database architecture has changed little. Based on this observation, we look at some interesting variants of conventional database systems that one might build that exploit recent hardware trends, and speculate on their performance through a detailed instruction-level breakdown of the major components involved in a transaction processing database system (Shore) running a subset of TPC-C. Rather than simply profiling Shore, we progressively modified it so that after every feature removal or optimization, we had a (faster) working system that fully ran our workload. Overall, we identify overheads and optimizations that explain a total difference of about a factor of 20x in raw performance. We also show that there is no single \\\"high pole in the tent\\\" in modern (memory resident) database systems, but that substantial time is spent in logging, latching, locking, B-tree, and buffer management operations.\",\n \"Title: Adaptive Query Processing: Technology in Evolution\\nYear: 2000\\n\\nAbstract: As query engines are scaled and federated, they must cope with highly unpredictable and changeable environments. In the Telegraph project, we are attempting to architect and implement a continuously adaptive query engine suitable for global-area systems, massive parallelism, and sensor networks. To set the stage for our research, we present a survey of prior work on adaptive query processing, focusing on three characterizations of adaptivity: the frequency of adaptivity, the effects of adaptivity, and the extent of adaptivity. Given this survey, we sketch directions for research in the Telegraph project.\",\n \"Title: VTrack: accurate, energy-aware road traffic delay estimation using mobile phones\\nYear: 2009\\n\\nAbstract: Traffic delays and congestion are a major source of inefficiency, wasted fuel, and commuter frustration. Measuring and localizing these delays, and routing users around them, is an important step towards reducing the time people spend stuck in traffic. As others have noted, the proliferation of commodity smartphones that can provide location estimates using a variety of sensors---GPS, WiFi, and/or cellular triangulation---opens up the attractive possibility of using position samples from drivers' phones to monitor traffic delays at a fine spatiotemporal granularity. This paper presents VTrack, a system for travel time estimation using this sensor data that addresses two key challenges: energy consumption and sensor unreliability. While GPS provides highly accurate location estimates, it has several limitations: some phones don't have GPS at all, the GPS sensor doesn't work in \\\"urban canyons\\\" (tall buildings and tunnels) or when the phone is inside a pocket, and the GPS on many phones is power-hungry and drains the battery quickly. In these cases, VTrack can use alternative, less energy-hungry but noisier sensors like WiFi to estimate both a user's trajectory and travel time along the route. VTrack uses a hidden Markov model (HMM)-based map matching scheme and travel time estimation method that interpolates sparse data to identify the most probable road segments driven by the user and to attribute travel times to those segments. We present experimental results from real drive data and WiFi access point sightings gathered from a deployment on several cars. We show that VTrack can tolerate significant noise and outages in these location estimates, and still successfully identify delay-prone segments, and provide accurate enough delays for delay-aware routing algorithms. We also study the best sampling strategies for WiFi and GPS sensors for different energy cost regimes.\",\n \"Title: A measurement study of vehicular internet access using in situ Wi-Fi networks\\nYear: 2006\\n\\nAbstract: The impressive penetration of 802.11-based wireless networks in many metropolitan areas around the world offers, for the first time, the opportunity of a \\\"grassroots\\\" wireless Internet service provided by users who \\\"open up\\\" their 802.11 (Wi-Fi) access points in a controlled manner to mobile clients. While there are many business, legal, and policy issues to be ironed out for this vision to become reality, we are concerned in this paper with an important technical question surrounding such a system: can such an unplanned network service provide reasonable performance to network clients moving in cars at vehicular speeds.To answer this question, we present the results of a measurement study carried out over 290 \\\"drive hours\\\" over a few cars under typical driving conditions, in and around the Boston metropolitan area (some of our data also comes from a car in Seattle). With a simple caching optimization to speed-up IP address acquisition, we find that for our driving patterns the median duration of link-layer connectivity at vehicular speeds is 13 seconds, the median connection upload bandwidth is 30 KBytes/s, and that the mean duration between successful associations to APs is 75 seconds. We also find that connections are equally probable across a range of urban speeds (up to 60 km/hour in our measurements). Our end-to-end TCP upload experiments had a median throughput of about 30 KBytes/s, which is consistent with typical uplink speeds of home broadband links in the US. The median TCP connection is capable of uploading about 216 KBytes of data.Our high-level conclusion is that grassroots Wi-Fi networks are viable for a variety of applications, particularly ones that can tolerate intermittent connectivity. We discuss how our measurement results can improve transport protocols in such networks.\",\n \"Title: Counting with the crowd\\nYear: 2012\\n\\nAbstract: In this paper, we address the problem of selectivity estimation in a crowdsourced database. Specifically, we develop several techniques for using workers on a crowdsourcing platform like Amazon's Mechanical Turk to estimate the fraction of items in a dataset (e.g., a collection of photos) that satisfy some property or predicate (e.g., photos of trees). We do this without explicitly iterating through every item in the dataset. This is important in crowd-sourced query optimization to support predicate ordering and in query evaluation, when performing a GROUP BY operation with a COUNT or AVG aggregate. We compare sampling item labels, a traditional approach, to showing workers a collection of items and asking them to estimate how many satisfy some predicate. Additionally, we develop techniques to eliminate spammers and colluding attackers trying to skew selectivity estimates when using this count estimation approach. We find that for images, counting can be much more effective than sampled labeling, reducing the amount of work necessary to arrive at an estimate that is within 1% of the true fraction by up to an order of magnitude, with lower worker latency. We also find that sampled labeling outperforms count estimation on a text processing task, presumably because people are better at quickly processing large batches of images than they are at reading strings of text. Our spammer detection technique, which is applicable to both the label- and count-based approaches, can improve accuracy by up to two orders of magnitude.\",\n \"Title: Mobiscopes for Human Spaces\\nYear: 2007\\n\\nAbstract: The proliferation of affordable mobile devices with processing and sensing capabilities, together with the rapid growth inubiquitous network connectivity, herald an era of mobiscopes: networked sensing applications that rely on multiple mobile sensors to accomplish global tasks. These distributed sensing systems extend the traditional sensor network model, introducing challenges in data management, data integrity, privacy, and network system design. Although several existing applications fit this description, they providetailored one-time solutions to what essentially is the same set of problems. It's time to work toward a general architecture thatidentifies common challenges and provides a general methodology for the design of future mobiscopes. Toward that end, this articlesurveys a variety of current and emerging mobile, networked, sensing applications; articulates their common challenges; and providesarchitectural guidelines and design directions for this important category of emerging distributed sensing systems. This article is partof a special issue on Building a Sensor-Rich World.\",\n \"Title: Cabernet: vehicular content delivery using WiFi\\nYear: 2008\\n\\nAbstract: Cabernet is a system for delivering data to and from moving vehicles using open 802.11 (WiFi) access points encountered opportunistically during travel. Using open WiFi access from the road can be challenging. Network connectivity in Cabernet is both fleeting (access points are typically within range for a few seconds) and intermittent (because the access points do not provide continuous coverage), and suffers from high packet loss rates over the wireless channel. On the positive side, WiFi data transfers, when available, can occur at broadband speeds. In this paper, we introduce two new components for improving openWiFi data delivery to moving vehicles: The first, QuickWiFi, is a streamlined client-side process to establish end-to-end connectivity, reducing mean connection time to less than 400 ms, from over 10 seconds when using standard wireless networking software. The second part, CTP, is a transport protocol that distinguishes congestion on the wired portion of the path from losses over the wireless link, resulting in a 2x throughput improvement over TCP. To characterize the amount of open WiFi capacity available to vehicular users, we deployed Cabernet on a fleet of 10 taxis in the Boston area. The long-term average transfer rate achieved was approximately 38 Mbytes/hour per car (86 kbit/s), making Cabernet a viable system for a number of non-interactive applications.\",\n \"Title: Workload-aware database monitoring and consolidation\\nYear: 2011\\n\\nAbstract: In most enterprises, databases are deployed on dedicated database servers. Often, these servers are underutilized much of the time. For example, in traces from almost 200 production servers from different organizations, we see an average CPU utilization of less than 4%. This unused capacity can be potentially harnessed to consolidate multiple databases on fewer machines, reducing hardware and operational costs. Virtual machine (VM) technology is one popular way to approach this problem. However, as we demonstrate in this paper, VMs fail to adequately support database consolidation, because databases place a unique and challenging set of demands on hardware resources, which are not well-suited to the assumptions made by VM-based consolidation. Instead, our system for database consolidation, named Kairos, uses novel techniques to measure the hardware requirements of database workloads, as well as models to predict the combined resource utilization of those workloads. We formalize the consolidation problem as a non-linear optimization program, aiming to minimize the number of servers and balance load, while achieving near-zero performance degradation. We compare Kairos against virtual machines, showing up to a factor of 12× higher throughput on a TPC-C-like benchmark. We also tested the effectiveness of our approach on real-world data collected from production servers at Wikia.com, Wikipedia, Second Life, and MIT CSAIL, showing absolute consolidation ratios ranging between 5.5:1 and 17:1.\",\n \"Title: Fault-tolerance in the Borealis distributed stream processing system\\nYear: 2008\\n\\nAbstract: We present a replication-based approach to fault-tolerant distributed stream processing in the face of node failures, network failures, and network partitions. Our approach aims to reduce the degree of inconsistency in the system while guaranteeing that available inputs capable of being processed are processed within a specified time threshold. This threshold allows a user to trade availability for consistency: a larger time threshold decreases availability but limits inconsistency, while a smaller threshold increases availability but produces more inconsistent results based on partial data. In addition, when failures heal, our scheme corrects previously produced results, ensuring eventual consistency.Our scheme uses a data-serializing operator to ensure that all replicas process data in the same order, and thus remain consistent in the absence of failures. To regain consistency after a failure heals, we experimentally compare approaches based on checkpoint/redo and undo/redo techniques and illustrate the performance trade-offs between these schemes.\",\n \"Title: Active Learning for Crowd-Sourced Databases\\nYear: 2012\\n\\nAbstract: Crowd-sourcing has become a popular means of acquiring labeled data for a wide variety of tasks where humans are more accurate than computers, e.g., labeling images, matching objects, or analyzing sentiment. However, relying solely on the crowd is often impractical even for data sets with thousands of items, due to time and cost constraints of acquiring human input (which cost pennies and minutes per label). In this paper, we propose algorithms for integrating machine learning into crowd-sourced databases, with the goal of allowing crowd-sourcing applications to scale, i.e., to handle larger datasets at lower costs. The key observation is that, in many of the above tasks, humans and machine learning algorithms can be complementary, as humans are often more accurate but slow and expensive, while algorithms are usually less accurate, but faster and cheaper. Based on this observation, we present two new active learning algorithms to combine humans and algorithms together in a crowd-sourced database. Our algorithms are based on the theory of non-parametric bootstrap, which makes our results applicable to a broad class of machine learning models. Our results, on three real-life datasets collected with Amazon's Mechanical Turk, and on 15 well-known UCI data sets, show that our methods on average ask humans to label one to two orders of magnitude fewer items to achieve the same accuracy as a baseline that labels random images, and two to eight times fewer questions than previous active learning schemes.\",\n \"Title: Partial replay of long-running applications\\nYear: 2011\\n\\nAbstract: Bugs in deployed software can be extremely difficult to track down. Invasive logging techniques, such as logging all non-deterministic inputs, can incur substantial runtime overheads. This paper shows how symbolic analysis can be used to re-create path equivalent executions for very long running programs such as databases and web servers. The goal is to help developers debug such long-running programs by allowing them to walk through an execution of the last few requests or transactions leading up to an error. The challenge is to provide this functionality without the high runtime overheads associated with traditional replay techniques based on input logging or memory snapshots. Our approach achieves this by recording a small amount of information about program execution, such as the direction of branches taken, and then using symbolic analysis to reconstruct the execution of the last few inputs processed by the application, as well as the state of memory before these inputs were executed. We implemented our technique in a new tool called bbr. In this paper, we show that it can be used to replay bugs in long-running single-threaded programs starting from the middle of an execution. We show that bbr incurs low recording overhead (avg. of 10%) during program execution, which is much less than existing replay schemes. We also show that it can reproduce real bugs from web servers, database systems, and other common utilities.\",\n \"Title: Information Survival Threshold In Sensor And P2p Networks\\nYear: 2007\\n\\nAbstract: Consider a network of, say, sensors, or P2P nodes, or bluetooth-enabled cell-phones, where nodes transmit information to each other and where links and nodes can go up or down. Consider also a 'datum', that is, a piece of information, like a report of an emergency condition in a sensor network, a national traditional song, or a mobile phone virus. How often should nodes transmit the datum to each other, so that the datum can survive (or, in the virus case, under what conditions will the virus die out)? Clearly, the link and node fault probabilities are important - what else is needed to ascertain the survivability of the datum? We propose and solve the problem using non-linear dynamical systems and fixed point stability theorems. We provide a closed-form formula that, surprisingly, depends on only one additional parameter, the largest eigenvalue of the connectivity matrix. We illustrate the accuracy of our analysis on realistic and real settings, like mote sensor networks from Intel and MIT, as well as Gnutella and P2P networks.\",\n \"Title: A demonstration of DBWipes: clean as you query\\nYear: 2012\\n\\nAbstract: As data analytics becomes mainstream, and the complexity of the underlying data and computation grows, it will be increasingly important to provide tools that help analysts understand the underlying reasons when they encounter errors in the result. While data provenance has been a large step in providing tools to help debug complex workflows, its current form has limited utility when debugging aggregation operators that compute a single output from a large collection of inputs. Traditional provenance will return the entire input collection, which has very low precision. In contrast, users are seeking precise descriptions of the inputs that caused the errors. We propose a Ranked Provenance System, which identifies subsets of inputs that influenced the output error, describes each subset with human readable predicates and orders them by contribution to the error. In this demonstration, we will present DBWipes, a novel data cleaning system that allows users to execute aggregate queries, and interactively detect, understand, and clean errors in the query results. Conference attendees will explore anomalies in campaign donations from the current US presidential election and in readings from a 54-node sensor deployment.\",\n \"Title: Processing and visualizing the data in tweets\\nYear: 2011\\n\\nAbstract: Microblogs such as Twitter provide a valuable stream of diverse user-generated data. While the data extracted from Twitter is generally timely and accurate, the process by which developers extract structured data from the tweet stream is ad-hoc and requires reimplementation of common data manipulation primitives. In this paper, we present two systems for querying and extracting structure from Twitter-embedded data. The first, TweeQL, provides a streaming SQL-like interface to the Twitter API, making common tweet processing tasks simpler. The second, TwitInfo, shows how end-users can interact with and understand aggregated data from the tweet stream, in addition to showcasing the power of the TweeQL language. Together these systems show the richness of content that can be extracted from Twitter.\",\n \"Title: Partitioning techniques for fine-grained indexing\\nYear: 2011\\n\\nAbstract: Many data-intensive websites use databases that grow much faster than the rate that users access the data. Such growing datasets lead to ever-increasing space and performance overheads for maintaining and accessing indexes. Furthermore, there is often considerable skew with popular users and recent data accessed much more frequently. These observations led us to design Shinobi, a system which uses horizontal partitioning as a mechanism for improving query performance to cluster the physical data, and increasing insert performance by only indexing data that is frequently accessed. We present database design algorithms that optimally partition tables, drop indexes from partitions that are infrequently queried, and maintain these partitions as workloads change. We show a 60脳 performance improvement over traditionally indexed tables using a real-world query workload derived from a traffic monitoring application\",\n \"Title: Performance tradeoffs in read-optimized databases\\nYear: 2006\\n\\nAbstract: Database systems have traditionally optimized performance for write-intensive workloads. Recently, there has been renewed interest in architectures that optimize read performance by using column-oriented data representation and light-weight compression. This previous work has shown that under certain broad classes of workloads, column-based systems can outperform row-based systems. Previous work, however, has not characterized the precise conditions under which a particular query workload can be expected to perform better on a column-oriented database.In this paper we first identify the distinctive components of a read-optimized DBMS and describe our implementation of a high-performance query engine that can operate on both row and column-oriented data. We then use our prototype to perform an in-depth analysis of the tradeoffs between column and row-oriented architectures. We explore these tradeoffs in terms of disk bandwidth, CPU cache latency, and CPU cycles. We show that for most database workloads, a carefully designed column system can outperform a carefully designed row system, sometimes by an order of magnitude. We also present an analytical model to predict whether a given workload on a particular hardware configuration is likely to perform better on a row or column-based system.\",\n \"Title: Twitinfo: aggregating and visualizing microblogs for event exploration\\nYear: 2011\\n\\nAbstract: Microblogs are a tremendous repository of user-generated content about world events. However, for people trying to understand events by querying services like Twitter, a chronological log of posts makes it very difficult to get a detailed understanding of an event. In this paper, we present TwitInfo, a system for visualizing and summarizing events on Twitter. TwitInfo allows users to browse a large collection of tweets using a timeline-based display that highlights peaks of high tweet activity. A novel streaming algorithm automatically discovers these peaks and labels them meaningfully using text from the tweets. Users can drill down to subevents, and explore further via geolocation, sentiment, and popular URLs. We contribute a recall-normalized aggregate sentiment visualization to produce more honest sentiment overviews. An evaluation of the system revealed that users were able to reconstruct meaningful summaries of events in a small amount of time. An interview with a Pulitzer Prize-winning journalist suggested that the system would be especially useful for understanding a long-running event and for identifying eyewitnesses. Quantitatively, our system can identify 80-100% of manually labeled peaks, facilitating a relatively complete view of each event studied.\",\n \"Title: Exploiting Correlated Attributes in Acquisitional Query Processing\\nYear: 2005\\n\\nAbstract: Sensor networks and other distributed information systems (such as the Web) must frequently access data that has a high per-attribute acquisition cost, in terms of energy, latency, or computational resources. When executing queries that contain several predicates over such expensive attributes, we observe that it can be beneficial to use correlations to automatically introduce low-cost attributes whose observation will allow the query processor to better estimate the selectivity of these expensive predicates. In particular, we show how to build conditional plans that branch into one or more sub-plans, each with a different ordering for the expensive query predicates, based on the runtime observation of low-cost attributes. We frame the problem of constructing the optimal conditional plan for a given user query and set of candidate low-cost attributes as an optimization problem. We describe an exponential time algorithm for finding such optimal plans, and describe a polynomial-time heuristic for identifying conditional plans that perform well in practice. We also show how to compactly model conditional probability distributions needed to identify correlations and build these plans. We evaluate our algorithms against several real-world sensor-network data sets, showing several-times performance increases for a variety of queries versus traditional optimization techniques.\",\n \"Title: ZStream: a cost-based query processor for adaptively detecting composite events\\nYear: 2009\\n\\nAbstract: Composite (or Complex) event processing (CEP) systems search sequences of incoming events for occurrences of user-specified event patterns. Recently, they have gained more attention in a variety of areas due to their powerful and expressive query language and performance potential. Sequentiality (temporal ordering) is the primary way in which CEP systems relate events to each other. In this paper, we present a CEP system called ZStream to efficiently process such sequential patterns. Besides simple sequential patterns, ZStream is also able to detect other patterns, including conjunction, disjunction, negation and Kleene closure. Unlike most recently proposed CEP systems, which use non-deterministic finite automata (NFA's) to detect patterns, ZStream uses tree-based query plans for both the logical and physical representation of query patterns. By carefully designing the underlying infrastructure and algorithms, ZStream is able to unify the evaluation of sequence, conjunction, disjunction, negation, and Kleene closure as variants of the join operator. Under this framework, a single pattern in ZStream may have several equivalent physical tree plans, with different evaluation costs. We propose a cost model to estimate the computation costs of a plan. We show that our cost model can accurately capture the actual runtime behavior of a plan, and that choosing the optimal plan can result in a factor of four or more speedup versus an NFA based approach. Based on this cost model and using a simple set of statistics about operator selectivity and data rates, ZStream is able to adaptively and seamlessly adjust the order in which it detects patterns on the fly. Finally, we describe a dynamic programming algorithm used in our cost model to efficiently search for an optimal query plan for a given pattern.\",\n \"Title: Mesh Networking Research and Technology for Multihop Wireless Networks\\nYear: 2008\\n\\nAbstract: Mesh networking encompasses a broad class of wireless networks in which nodes collaboratively route packets. All mesh networks' benefits, such as lower costs, scalability, and easy installation, introduce new challenges that we must address.\",\n \"Title: Synthesizing entity matching rules by examples\\nYear: 2017\\n\\nAbstract: AbstractEntity matching (EM) is a critical part of data integration. We study how to synthesize entity matching rules from positive-negative matching examples. The core of our solution is program synthesis, a powerful tool to automatically generate rules (or programs) that satisfy a given high-level specification, via a predefined grammar. This grammar describes a General Boolean Formula (GBF) that can include arbitrary attribute matching predicates combined by conjunctions (∧), disjunctions (∨) and negations (¬), and is expressive enough to model EM problems, from capturing arbitrary attribute combinations to handling missing attribute values. The rules in the form of GBF are more concise than traditional EM rules represented in Disjunctive Normal Form (DNF). Consequently, they are more interpretable than decision trees and other machine learning algorithms that output deep trees with many branches. We present a new synthesis algorithm that, given only positive-negative examples as input, synthesizes EM rules that are effective over the entire dataset. Extensive experiments show that we outperform other interpretable rules (e.g., decision trees with low depth) in effectiveness, and are comparable with non-interpretable tools (e.g., decision trees with high depth, gradient-boosting trees, random forests and SVM).\",\n \"Title: \\\"Extra-sensory perception\\\" for wireless networks\\nYear: 2010\\n\\nAbstract: Commodity smartphones and tablet devices now come equipped with a variety of sensors, including accelerometers, multiple positioning sensors, magnetic compasses, and inertial sensors (gyros). In this paper, we posit that these sensors can be profitably used to improve the performance of wireless network protocols running on these mobile devices, and introduce the idea of using external sensor hints for this purpose. We focus on mobility hints, including the device's state of motion, speed, direction of movement, and position. We outline how these hints can be used to: increase throughput by adapting bit rate selection to the state of movement; reduce the bandwidth required for estimating link delivery probabilities; improve the connectivity of routes in vehicular mesh networks using directionality hints; and enable access points to tailor the management of clients to their mobility.\",\n \"Title: The emergence of a networking primitive in wireless sensor networks\\nYear: 2008\\n\\nAbstract: The wireless sensor network community approached networking abstractions as an open question, allowing answers to emerge with time and experience. The Trickle algorithm has become a basic mechanism used in numerous protocols and systems. Trickle brings nodes to eventual consistency quickly and efficiently while remaining remarkably robust to variations in network density, topology, and dynamics. Instead of flooding a network with packets, Trickle uses a \\\"polite gossip\\\" policy to control send rates so each node hears just enough packets to stay consistent. This simple mechanism enables Trickle to scale to 1000-fold changes in network density, reach consistency in seconds, and require only a few bytes of state yet impose a maintenance cost of a few sends an hour. Originally designed for disseminating new code, experience has shown Trickle to have much broader applicability, including route maintenance and neighbor discovery. This paper provides an overview of the research challenges wireless sensor networks face, describes the Trickle algorithm, and outlines several ways it is used today.\",\n \"Title: The design of an acquisitional query processor for sensor networks\\nYear: 2003\\n\\nAbstract: We discuss the design of an acquisitional query processor for data collection in sensor networks. Acquisitional issues are those that pertain to where, when, and how often data is physically acquired (sampled) and delivered to query processing operators. By focusing on the locations and costs of acquiring data, we are able to significantly reduce power consumption over traditional passive systems that assume the a priori existence of data. We discuss simple extensions to SQL for controlling data acquisition, and show how acquisitional issues influence query optimization, dissemination, and execution. We evaluate these issues in the context of TinyDB, a distributed query processor for smart sensor devices, and show how acquisitional techniques can provide significant reductions in power consumption on our sensor devices.\",\n \"Title: Querying continuous functions in a database system\\nYear: 2008\\n\\nAbstract: Many scientific, financial, data mining and sensor network applications need to work with continuous, rather than discrete data e.g., temperature as a function of location, or stock prices or vehicle trajectories as a function of time. Querying raw or discrete data is unsatisfactory for these applications -- e.g., in a sensor network, it is necessary to interpolate sensor readings to predict values at locations where sensors are not deployed. In other situations, raw data can be inaccurate owing to measurement errors, and it is useful to fit continuous functions to raw data and query the functions, rather than raw data itself -- e.g., fitting a smooth curve to noisy sensor readings, or a smooth trajectory to GPS data containing gaps or outliers. Existing databases do not support storing or querying continuous functions, short of brute-force discretization of functions into a collection of tuples. We present FunctionDB, a novel database system that treats mathematical functions as first-class citizens that can be queried like traditional relations. The key contribution of FunctionDB is an efficient and accurate algebraic query processor - for the broad class of multi-variable polynomial functions, FunctionDB executes queries directly on the algebraic representation of functions without materializing them into discrete points, using symbolic operations: zero finding, variable substitution, and integration. Even when closed form solutions are intractable, FunctionDB leverages symbolic approximation operations to improve performance. We evaluate FunctionDB on real data sets from a temperature sensor network, and on traffic traces from Boston roads. We show that operating in the functional domain has substantial advantages in terms of accuracy (15-30%) and up to order of magnitude (10x-100x) performance wins over existing approaches that represent models as discrete collections of points.\",\n \"Title: CORADD: correlation aware database designer for materialized views and indexes\\nYear: 2010\\n\\nAbstract: We describe an automatic database design tool that exploits correlations between attributes when recommending materialized views (MVs) and indexes. Although there is a substantial body of related work exploring how to select an appropriate set of MVs and indexes for a given workload, none of this work has explored the effect of correlated attributes (e.g., attributes encoding related geographic information) on designs. Our tool identifies a set of MVs and secondary indexes such that correlations between the clustered attributes of the MVs and the secondary indexes are enhanced, which can dramatically improve query performance. It uses a form of Integer Linear Programming (ILP) called ILP Feedback to pick the best set of MVs and indexes for given database size constraints. We compare our tool with a state-of-the-art commercial database designer on two workloads, APB-1 and SSB (Star Schema Benchmark---similar to TPC-H). Our results show that a correlation-aware database designer can improve query performance up to 6 times within the same space budget when compared to a commercial database designer.\",\n \"Title: Distributed regression: an efficient framework for modeling sensor network data\\nYear: 2004\\n\\nAbstract: We present distributed regression, an efficient and general framework for in-network modeling of sensor data. In this framework, the nodes of the sensor network collaborate to optimally fit a global function to each of their local measurements. The algorithm is based upon kernel linear regression, where the model takes the form of a weighted sum of local basis functions; this provides an expressive yet tractable class of models for sensor network data. Rather than transmitting data to one another or outside the network, nodes communicate constraints on the model parameters, drastically reducing the communication required. After the algorithm is run, each node can answer queries for its local region, or the nodes can efficiently transmit the parameters of the model to a user outside the network. We present an evaluation of the algorithm based upon data from a 48-node sensor network deployment at the Intel Research - Berkeley Lab, demonstrating that our distributed algorithm converges to the optimal solution at a fast rate and is very robust to packet losses.\",\n \"Title: Tweets as data: demonstration of TweeQL and Twitinfo\\nYear: 2011\\n\\nAbstract: Microblogs such as Twitter are a tremendous repository of user-generated content. Increasingly, we see tweets used as data sources for novel applications such as disaster mapping, brand sentiment analysis, and real-time visualizations. In each scenario, the workflow for processing tweets is ad-hoc, and a lot of unnecessary work goes into repeating common data processing patterns. We introduce TweeQL, a stream query processing language that presents a SQL-like query interface for unstructured tweets to generate structured data for downstream applications. We have built several tools on top of TweeQL, most notably TwitInfo, an event timeline generation and exploration interface that summarizes events as they are discussed on Twitter. Our demonstration will allow the audience to interact with both TweeQL and TwitInfo to convey the value of data embedded in tweets.\",\n \"Title: C-Store: A Column-oriented DBMS\\nYear: 2005\\n\\nAbstract: This paper presents the design of a read-optimized relational DBMS that contrasts sharply with most current systems, which are write-optimized. Among the many differences in its design are: storage of data by column rather than by row, careful coding and packing of objects into storage including main memory during query processing, storing an overlapping collection of column-oriented projections, rather than the current fare of tables and indexes, a non-traditional implementation of transactions which includes high availability and snapshot isolation for read-only transactions, and the extensive use of bitmap indexes to complement B-tree structures.We present preliminary performance data on a subset of TPC-H and show that the system we are building, C-Store, is substantially faster than popular commercial products. Hence, the architecture looks very encouraging.\",\n \"Title: An Integration Framework for Sensor Networks and Data Stream Management Systems\\nYear: 2004\\n\\nAbstract: This demonstration shows an integrated query processing environment where users can seam- lessly query both a data stream management system and a sensor network with one query expression. By integrating the two query pro- cessing systems, the optimization goals of the sensor network (primarily power) and server network (primarily latency and quality) can be unifled into one quality of service metric. The demo shows various steps of the unifled optimization process for a sample query where the efiects of each step that the optimizer takes can be directly viewed using a quality of service monitor. Our demo includes sensors deployed in the demo area in a tiny mockup of a factory application.\",\n \"Title: Sync kit: a persistent client-side database caching toolkit for data intensive websites\\nYear: 2010\\n\\nAbstract: We introduce a client-server toolkit called Sync Kit that demonstrates how client-side database storage can improve the performance of data intensive websites. Sync Kit is designed to make use of the embedded relational database defined in the upcoming HTML5 standard to offload some data storage and processing from a web server onto the web browsers to which it serves content. Our toolkit provides various strategies for synchronizing relational database tables between the browser and the web server, along with a client-side template library so that portions web applications may be executed client-side. Unlike prior work in this area, Sync Kit persists both templates and data in the browser across web sessions, increasing the number of concurrent connections a server can handle by up to a factor of four versus that of a traditional server-only web stack and a factor of three versus a recent template caching approach.\",\n \"Title: Mobius: unified messaging and data serving for mobile apps\\nYear: 2012\\n\\nAbstract: Mobile application development is challenging for several reasons: intermittent and limited network connectivity, tight power constraints, server-side scalability concerns, and a number of fault-tolerance issues. Developers handcraft complex solutions that include client-side caching, conflict resolution, disconnection tolerance, and backend database sharding. To simplify mobile app development, we present Mobius, a system that addresses the messaging and data management challenges of mobile application development. Mobius introduces MUD (Messaging Unified with Data). MUD presents the programming abstraction of a logical table of data that spans devices and clouds. Applications using Mobius can asynchronously read from/write to MUD tables, and also receive notifications when tables change via continuous queries on the tables. The system combines dynamic client-side caching (with intelligent policies chosen on the server-side, based on usage patterns across multiple applications), notification services, flexible query processing, and a scalable and highly available cloud storage system. We present an initial prototype to demonstrate the feasibility of our design. Even in our initial prototype, remote read and write latency overhead is less than 52% when compared to a hand-tuned solution. Our dynamic caching reduces the number of messages by a factor of 4 to 8.5 when compared to fixed strategies, thus reducing latency, bandwidth, power, and server load costs, while also reducing data staleness.\",\n \"Title: Mobile applications need targeted micro-updates\\nYear: 2013\\n\\nAbstract: Smart-phone applications (\\\"apps\\\") run across a wide range of environmental conditions, locations, and hardware platforms. They are often subject to an array of interactions that are hard or impossible for developers to emulate or even anticipate during testing. Once an application is released, feedback obtained from users and from analytics over usage and performance data result in further modifications. Many of these changes are relatively small, and can often be parameterized.\",\n \"Title: Resource-Aware Wireless Sensor-Actuator Networks\\nYear: 2005\\n\\nAbstract: Innovations in wireless sensor networks (WSNs) have dramatically expanded the applicability of control technol- ogy in day-to-day life, by enabling the cost-effective deployment of large scale sensor-actuator systems. In this paper, we discuss the issues and challenges involved in deploying control-oriented applications over unreliable, resource-constrainedWSNs, and describe the design of our planned Sensor Control System (SCS) that can enable the rapid development and deployment of such applications.\",\n \"Title: Impact of double-blind reviewing on SIGMOD publication rates\\nYear: 2006\\n\\nAbstract: Starting with the 2001 SIGMOD conference, the SIGMOD Chair, in consultation with the SIGMOD Advisory Committee, imposed a double blind rule on all future SIGMOD conferences. While there are many reasons why double-blind reviewing might be a good idea, the one most frequently cited is that it is fairer to more junior researchers. It is not, however, without its problems, including anecdotal reports of papers being rejected because their authors failed to cite their own papers as related work in order to not violate the anonymity rules and a complication of the job of the program chair who must interpret and enforce the double-blind rules. One very qualified individual turned down an offer to be PC chair of an upcoming SIGMOD conference because he did not want to have to deal with the headaches of double-blind reviewing.\",\n \"Title: An energy-efficient querying framework in sensor networks for detecting node similarities\\nYear: 2006\\n\\nAbstract: We propose an energy-efficient framework, called SAF, for approximate querying and clustering of nodes in a sensor network. SAF uses simple time series forecasting models to predict sensor readings. The idea is to build these local models at each node, transmit them to the root of the network (the \\\"sink\\\"), and use them to approximately answer user queries. Our approach dramatically reduces communication relative to previous approaches for querying sensor networks by exploiting properties of these local models, since each sensor communicates with the sink only when its local model varies due to changes in the underlying data distribution. In our experimental results performed on a trace of real data, we observed on average about 150 message transmissions from each sensor over a week (including the learning phase) to correctly predict temperatures to within +/- 0.5°C.SAF also provides a mechanism to detect data similarities between nodes and organize nodes into clusters at the sink at no additional communication cost. This is again achieved by exploiting properties of our local time series models, and by means of a novel definition of data similarity between nodes that is based not on raw data but on the prediction values. Our clustering algorithm is both very efficient and provably optimal in the number of clusters. Our clusters have several interesting features: first, they can capture similarity between far away nodes that are not geographically adjacent; second, cluster membership to variations in sensors' local models; third, nodes within a cluster are not required to track the membership of other nodes in the cluster. We present a number of simulation-based experimental results that demonstrate these properties of SAF.\",\n \"Title: Task: Sensor Network In A Box\\nYear: 2005\\n\\nAbstract: Sensornet systems research is being conducted with various applications and deployment scenarios in mind. In many of these scenarios, the presumption is that the sensornet will be deployed and managed by users who do not have a background in computer science. In this paper we describe the \\\"Tiny Application Sensor Kit (TASK), a system we have designed for use by end-users with minimal sensornet sophistication. We describe the requirements that guided our design, the architecture of the system, and results from initial deployments. Based on our experience to date we present preliminary design principles and research challenges that arise in delivering sensornet research to end users.\",\n \"Title: UPI: a primary index for uncertain databases\\nYear: 2010\\n\\nAbstract: Uncertain data management has received growing attention from industry and academia. Many efforts have been made to optimize uncertain databases, including the development of special index data structures. However, none of these efforts have explored primary (clustered) indexes for uncertain databases, despite the fact that clustering has the potential to offer substantial speedups for non-selective analytic queries on large uncertain databases. In this paper, we propose a new index called a UPI (Uncertain Primary Index) that clusters heap files according to uncertain attributes with both discrete and continuous uncertainty distributions. Because uncertain attributes may have several possible values, a UPI on an uncertain attribute duplicates tuple data once for each possible value. To prevent the size of the UPI from becoming unmanageable, its size is kept small by placing low-probability tuples in a special Cutoff Index that is consulted only when queries for low-probability values are run. We also propose several other optimizations, including techniques to improve secondary index performance and techniques to reduce maintenance costs and fragmentation by buffering changes to the table and writing updates in sequential batches. Finally, we develop cost models for UPIs to estimate query performance in various settings to help automatically select tuning parameters of a UPI. We have implemented a prototype UPI and experimented on two real datasets. Our results show that UPIs can significantly (up to two orders of magnitude) improve the performance of uncertain queries both over clustered and unclustered attributes. We also show that our buffering techniques mitigate table fragmentation and keep the maintenance cost as low as or even lower than using an unclustered heap file.\",\n \"Title: MauveDB: supporting model-based user views in database systems\\nYear: 2006\\n\\nAbstract: Real-world data --- especially when generated by distributed measurement infrastructures such as sensor networks --- tends to be incomplete, imprecise, and erroneous, making it impossible to present it to users or feed it directly into applications. The traditional approach to dealing with this problem is to first process the data using statistical or probabilistic models that can provide more robust interpretations of the data. Current database systems, however, do not provide adequate support for applying models to such data, especially when those models need to be frequently updated as new data arrives in the system. Hence, most scientists and engineers who depend on models for managing their data do not use database systems for archival or querying at all; at best, databases serve as a persistent raw data store.In this paper we define a new abstraction called model-based views and present the architecture of MauveDB, the system we are building to support such views. Just as traditional database views provide logical data independence, model-based views provide independence from the details of the underlying data generating mechanism and hide the irregularities of the data by using models to present a consistent view to the users. MauveDB supports a declarative language for defining model-based views, allows declarative querying over such views using SQL, and supports several different materialization strategies and techniques to efficiently maintain them in the face of frequent updates. We have implemented a prototype system that currently supports views based on regression and interpolation, using the Apache Derby open source DBMS, and we present results that show the utility and performance benefits that can be obtained by supporting several different types of model-based views in a database system.\",\n \"Title: Model-Driven Data Acquisition in Sensor Networks\\nYear: 2004\\n\\nAbstract: Declarative queries are proving to be an attractive paradigm for in- teracting with networks of wireless sensors. The metaphor that \\\"the sensornet is a database\\\" is problematic, however, because sensors do not exhaustively represent the data in the real world. In order to map the raw sensor readings onto physical reality, a model of that reality is required to complement the readings. In this paper, we enrich interactive sensor querying with statistical modeling tech- niques. We demonstrate that such models can help provide answers that are both more meaningful, and, by introducing approximations with probabilistic confidences, significantly more efficient to com- pute in both time and energy. Utilizing the combination of a model and live data acquisition raises the challenging optimization prob- lem of selecting the best sensor readings to acquire, balancing the increase in the confidence of our answer against the communication and data acquisition costs in the network. We describe an expo- nential time algorithm for finding the optimal solution to this op- timization problem, and a polynomial-time heuristic for identifying solutions that perform well in practice. We evaluate our approach on several real-world sensor-network data sets, taking into account the real measured data and communication quality, demonstrating that our model-based approach provides a high-fidelity representation of the real phenomena and leads to significant performance gains ver- sus traditional data acquisition techniques.\",\n \"Title: Performance and resource modeling in highly-concurrent OLTP workloads\\nYear: 2013\\n\\nAbstract: Database administrators of Online Transaction Processing (OLTP) systems constantly face difficult questions. For example, \\\"What is the maximum throughput I can sustain with my current hardware?\\\", \\\"How much disk I/O will my system perform if the requests per second double?\\\", or \\\"What will happen if the ratio of transactions in my system changes?\\\". Resource prediction and performance analysis are both vital and difficult in this setting. Here the challenge is due to high degrees of concurrency, competition for resources, and complex interactions between transactions, all of which non-linearly impact performance. Although difficult, such analysis is a key component in enabling database administrators to understand which queries are eating up the resources, and how their system would scale under load. In this paper, we introduce our framework, called DBSeer, that addresses this problem by employing statistical models that provide resource and performance analysis and prediction for highly concurrent OLTP workloads. Our models are built on a small amount of training data from standard log information collected during normal system operation. These models are capable of accurately measuring several performance metrics, including resource consumption on a per-transaction-type basis, resource bottlenecks, and throughput at different load levels. We have validated these models on MySQL/Linux with numerous experiments on standard benchmarks (TPC-C) and real workloads (Wikipedia), observing high accuracy (within a few percent error) when predicting all of the above metrics.\",\n \"Title: Efficient Versioning for Scientific Array Databases\\nYear: 2012\\n\\nAbstract: In this paper, we describe a versioned database storage manager we are developing for the SciDB scientific database. The system is designed to efficiently store and retrieve array-oriented data, exposing a ``no-overwrite'' storage model in which each update creates a new ``version'' of an array. This makes it possible to perform comparisons of versions produced at different times or by different algorithms, and to create complex chains and trees of versions. We present algorithms to efficiently encode these versions, minimizing storage space while still providing efficient access to the data. Additionally, we present an optimal algorithm that, given a long sequence of versions, determines which versions to encode in terms of each other (using delta compression) to minimize total storage space or query execution cost. We compare the performance of these algorithms on real world data sets from the National Oceanic and Atmospheric Administration (NOAA), Open Street Maps, and several other sources. We show that our algorithms provide better performance than existing version control systems not optimized for array data, both in terms of storage size and access time, and that our delta-compression algorithms are able to substantially reduce the total storage space when versions exist with a high degree of similarity.\",\n \"Title: Processing analytical queries over encrypted data\\nYear: 2013\\n\\nAbstract: MONOMI is a system for securely executing analytical workloads over sensitive data on an untrusted database server. MONOMI works by encrypting the entire database and running queries over the encrypted data. MONOMI introduces split client/server query execution, which can execute arbitrarily complex queries over encrypted data, as well as several techniques that improve performance for such workloads, including per-row precomputation, space-efficient encryption, grouped homomorphic addition, and pre-filtering. Since these optimizations are good for some queries but not others, MONOMI introduces a designer for choosing an efficient physical design at the server for a given workload, and a planner to choose an efficient execution plan for a given query at runtime. A prototype of MONOMI running on top of Postgres can execute most of the queries from the TPC-H benchmark with a median overhead of only 1.24× (ranging from 1.03×to 2.33×) compared to an un-encrypted Postgres database where a compromised server would reveal all data.\",\n \"Title: Low overhead concurrency control for partitioned main memory databases\\nYear: 2010\\n\\nAbstract: Database partitioning is a technique for improving the performance of distributed OLTP databases, since \\\"single partition\\\" transactions that access data on one partition do not need coordination with other partitions. For workloads that are amenable to partitioning, some argue that transactions should be executed serially on each partition without any concurrency at all. This strategy makes sense for a main memory database where there are no disk or user stalls, since the CPU can be fully utilized and the overhead of traditional concurrency control, such as two-phase locking, can be avoided. Unfortunately, many OLTP applications have some transactions which access multiple partitions. This introduces network stalls in order to coordinate distributed transactions, which will limit the performance of a database that does not allow concurrency. In this paper, we compare two low overhead concurrency control schemes that allow partitions to work on other transactions during network stalls, yet have little cost in the common case when concurrency is not needed. The first is a light-weight locking scheme, and the second is an even lighter-weight type of speculative concurrency control that avoids the overhead of tracking reads and writes, but sometimes performs work that eventually must be undone. We quantify the range of workloads over which each technique is beneficial, showing that speculative concurrency control generally outperforms locking as long as there are few aborts or few distributed transactions that involve multiple rounds of communication. On a modified TPC-C benchmark, speculative concurrency control can improve throughput relative to the other schemes by up to a factor of two.\",\n \"Title: VoxNet: An Interactive, Rapidly-Deployable Acoustic Monitoring Platform\\nYear: 2008\\n\\nAbstract: Distributed acoustic sensing underlies an increasingly important class of sensor network applications, from habitat monitoring and bio acoustic census to security applications and virtual fences. VoxNet is a complete hardware and software platform for distributed acoustic monitoring applications that focuses on three key goals:(1) rapid deployment in realistic environments;(2) a high level programming language that abstracts the user from platform and network details and compiles into a high performance distributed application; and(3) an interactive usage model based on run-time installable programs, with the ability to run the same high level program seamlessly over live or stored data. The VoxNet hardware is self-contained and weather-resistant, and supports a four-channel microphone array with automated time synchronization, localization, and network coordination. Using VoxNet, an investigator can visualize phenomena in real-time, develop and tune on-line analysis, and record raw data for off-line analysis and archival. This paper describes both the hardware and software elements of the platform, as well as the architecture required to support distributed programs running over a heterogeneous network.We characterize the performance of the platform, using both microbenchmarks that evaluate specific aspects of the platform and a real application running in the field.\",\n \"Title: Scoop: An Adaptive Indexing Scheme For Stored Data In Sensor Networks\\nYear: 2007\\n\\nAbstract: We present the design of Scoop, a system for indexing and querying stored data in sensor networks. Scoop works by collecting statistics about the rate of queries and distribution of sensor readings in a sensor network, and uses those statistics to build an index that tells nodes where in the network to store their data. Using this index, a queries over that stored data can be answered efficiently, without flooding those queries throughout the network. This approach offers a substantial advantage over other solutions that either store all data externally on a basestation (requiring every reading to be collected from all nodes), or that store all data locally on the node that produced it (requiring queries to be flooded throughout the network). Our results show that Scoop offers a factor of four reduction in message transmissions relative to existing techniques in a real implementation on a 64-node mote-based sensor network. These results also show that Scoop is able to efficiently adapt to changes in the distribution of data and queries.\",\n \"Title: The end of an architectural era: (it's time for a complete rewrite)\\nYear: 2007\\n\\nAbstract: In previous papers [SC05, SBC+07], some of us predicted the end of \\\"one size fits all\\\" as a commercial relational DBMS paradigm. These papers presented reasons and experimental evidence that showed that the major RDBMS vendors can be outperformed by 1--2 orders of magnitude by specialized engines in the data warehouse, stream processing, text, and scientific database markets. Assuming that specialized engines dominate these markets over time, the current relational DBMS code lines will be left with the business data processing (OLTP) market and hybrid markets where more than one kind of capability is required. In this paper we show that current RDBMSs can be beaten by nearly two orders of magnitude in the OLTP market as well. The experimental evidence comes from comparing a new OLTP prototype, H-Store, which we have built at M.I.T. to a popular RDBMS on the standard transactional benchmark, TPC-C. We conclude that the current RDBMS code lines, while attempting to be a \\\"one size fits all\\\" solution, in fact, excel at nothing. Hence, they are 25 year old legacy code lines that should be retired in favor of a collection of \\\"from scratch\\\" specialized engines. The DBMS vendors (and the research community) should start with a clean sheet of paper and design systems for tomorrow's requirements, not continue to push code lines and architectures designed for yesterday's needs.\",\n \"Title: Materialization Strategies In A Column-Oriented Dbms\\nYear: 2007\\n\\nAbstract: There has been renewed interest in column-oriented database architectures in recent years. For read-mostly query workloads such as those found in data warehouse and decision support applications, \\\"column-stores\\\" have been shown to perform particularly well relative to \\\"row-stores.\\\" In order for column-stores to be readily adopted as a replacement for row-stores, however, they must present the same interface to client applications as do row stores, which implies that they must output row-store-style tuples.Thus, the input columns stored on disk must be converted to rows at some point in the query plan, but the optimal point at which to do the conversion is not obvious. This problem can be considered as the opposite of the projection problem in row-store systems: while row-stores need to determine where in query plans to place projection operators to make tuples narrower, column-stores need to determine when to combine single-column projections into wider tuples. This paper describes a variety of strategies for tuple construction and intermediate result representations and provides a systematic evaluation of these strategies.\",\n \"Title: The Case for a Signal-Oriented Data Stream Management System\\nYear: 2007\\n\\nAbstract: Sensors capable of sensing phenomena at high data rates—on the order of tens to hundreds of thousands of samples per second—are useful in many industrial, civil engineering, scientific, networking, and medical applications. In these applications, high-rate streams of data produced by sensors must be processed and analyzed using a combination ofbothevent-stream and signal-processing operations. This paper motivates the need for a data management and continu- ous query processing architecture that integrates these two different desired classes of functions into a single, unified software system. The key goals of such a system include: the ability to treat a se- quence of samples that constitute a \\\"signal segment\\\" as a basic data type; ease of writing arbitrary event-stream and signal-processing functions; the ability to process several million samples per second on conventional PC hardware; and the ability to distribute applica- tion code across both PCs and sensor nodes.\",\n \"Title: Using Probabilistic Models for Data Management in Acquisitional Environments\\nYear: 2005\\n\\nAbstract: Traditional database systems, particularly those fo- cused on capturing and managing data from the real world, are poorly equipped to deal with the noise, loss, and uncertainty in data. We discuss a suite of techniques based on probabilistic models that are designed to allow database to tolerate noise and loss. These techniques are based on exploiting cor- relations to predict missing values and identify out- liers. Interestingly, correlations also provide a way to give approximate answers to users at a signifi- cantly lower cost and enable a range of new types of queries over the correlation structure itself. We illustrate a host of applications for our new tech- niques and queries, ranging from sensor networks to network monitoring to data stream management. We also present a unified architecture for integrat- ing such models into database systems, focusing in particular on acquisitional systems where the cost of capturing data (e.g., from sensors) is itself a sig- nificant part of the query processing cost.\",\n \"Title: Human-powered sorts and joins\\nYear: 2011\\n\\nAbstract: Crowdsourcing markets like Amazon's Mechanical Turk (MTurk) make it possible to task people with small jobs, such as labeling images or looking up phone numbers, via a programmatic interface. MTurk tasks for processing datasets with humans are currently designed with significant reimplementation of common workflows and ad-hoc selection of parameters such as price to pay per task. We describe how we have integrated crowds into a declarative workflow engine called Qurk to reduce the burden on workflow designers. In this paper, we focus on how to use humans to compare items for sorting and joining data, two of the most common operations in DBMSs. We describe our basic query interface and the user interface of the tasks we post to MTurk. We also propose a number of optimizations, including task batching, replacing pairwise comparisons with numerical ratings, and pre-filtering tables before joining them, which dramatically reduce the overall cost of running sorts and joins on the crowd. In an experiment joining two sets of images, we reduce the overall cost from $67 in a naive implementation to about $3, without substantially affecting accuracy or latency. In an end-to-end experiment, we reduced cost by a factor of 14.5.\",\n \"Title: A demonstration of HYRISE: a main memory hybrid storage engine\\nYear: 2011\\n\\nAbstract: AbstractWe propose to demonstrate HYRISE, a main memory hybrid database system, which automatically partitions tables into vertical partitions consisting of variable numbers of columns based on access patterns to each table. Using an accurate model of cache misses, HYRISE is able to predict the performance of different partitionings, and to automatically select the best partitions using an automated database partitioning algorithm. Our demonstration will show the results of the physical partitioning based on different query workloads, allowing demo attendees to visualize, fine-tune, and modify the partitioning using a GUI. It will then show how the various physical designs affect the query plans and the performance of the database as a whole. Attendees can thus experiment with various physical models, and can grasp the potential of hybrid partitionings, which achieve a 20% to 400% performance improvement over pure all-column or all-row designs on our realistic hybrid workload derived from customer applications.\",\n \"Title: Continuously adaptive continuous queries over streams\\nYear: 2002\\n\\nAbstract: We present a continuously adaptive, continuous query (CACQ) implementation based on the eddy query processing framework. We show that our design provides significant performance benefits over existing approaches to evaluating continuous queries, not only because of its adaptivity, but also because of the aggressive cross-query sharing of work and space that it enables. By breaking the abstraction of shared relational algebra expressions, our Telegraph CACQ implementation is able to share physical operators --- both selections and join state --- at a very fine grain. We augment these features with a grouped-filter index to simultaneously evaluate multiple selection predicates. We include measurements of the performance of our core system, along with a comparison to existing continuous query approaches.\",\n \"Title: CHIC: a combination-based recommendation system\\nYear: 2013\\n\\nAbstract: Current recommender systems are focused largely on recommending items based on similarity. For instance, Netflix can recommend movies similar to previously viewed movies, and Amazon can recommend items based on ratings of similar users. Although similarity-based recommendation works well for books and movies, it provides an incomplete solution for items such as clothing or furniture which are inherently used in combination with other items of the same type, e.g., shirt with pants, and desk with a chair. As a result, the decision to buy a clothing or furniture item depends not only on the item itself, but also on how well it works with other items of that type. Recommending such items therefore requires a combination-based recommendation system that given an item, can suggest interesting and diverse combinations containing that item. This problem is challenging because features affecting combination quality are often difficult to identify; quality, being a function of all items in the combination, cannot be computed independently; and there are an exponential number of combinations to explore. In this demonstration, we present CHIC, a first-of-its-kind, combination-based recommendation system for clothing. The audience will interact with our system through the CHIC mobile app which allows the user to take a picture of a clothing item and search for interesting combinations containing the item instantly. The audience can also compete with CHIC to create alternate ensembles and compare quality. Finally, we highlight via visualizations the core modules of CHIC including model building and our novel search and classification algorithm, C-Search.\",\n \"Title: Automatic partitioning of database applications\\nYear: 2012\\n\\nAbstract: Database-backed applications are nearly ubiquitous in our daily lives. Applications that make many small accesses to the database create two challenges for developers: increased latency and wasted resources from numerous network round trips. A well-known technique to improve transactional database application performance is to convert part of the application into stored procedures that are executed on the database server. Unfortunately, this conversion is often difficult. In this paper we describe Pyxis, a system that takes database-backed applications and automatically partitions their code into two pieces, one of which is executed on the application server and the other on the database server. Pyxis profiles the application and server loads, statically analyzes the code's dependencies, and produces a partitioning that minimizes the number of control transfers as well as the amount of data sent during each transfer. Our experiments using TPC-C and TPC-W show that Pyxis is able to generate partitions with up to 3x reduction in latency and 1.7x improvement in throughput when compared to a traditional non-partitioned implementation and has comparable performance to that of a custom stored procedure implementation.\",\n \"Title: The Case for RodentStore, an Adaptive, Declarative Storage System\\nYear: 2009\\n\\nAbstract: Recent excitement in the database community surrounding new applications?analytic, scientific, graph, geospatial, etc.?has led to an explosion in research on database storage systems. New storage systems are vital to the database community, as they are at the heart of making database systems perform well in new application domains. Unfortunately, each such system also represents a substantial engineering effort including a great deal of duplication of mechanisms for features such as transactions and caching. In this paper, we make the case for RodentStore, an adaptive and declarative storage system providing a high-level interface for describing the physical representation of data. Specifically, RodentStore uses a declarative storage algebra whereby administrators (or database design tools) specify how a logical schema should be grouped into collections of rows, columns, and/or arrays, and the order in which those groups should be laid out on disk. We describe the key operators and types of our algebra, outline the general architecture of RodentStore, which interprets algebraic expressions to generate a physical representation of the data, and describe the interface between RodentStore and other parts of a database system, such as the query optimizer and executor. We provide a case study of the potential use of RodentStore in representing dense geospatial data collected from a mobile sensor network, showing the ease with which different storage layouts can be expressed using some of our algebraic constructs and the potential performance gains that a RodentStore-built storage system can offer.\",\n \"Title: Data management in sensor networks\\nYear: 2006\\n\\nAbstract: This tutorial will cover recent topics in data management for sensor networks, focusing in particular on high-level systems and languages for querying stored and streaming data in such networks. We will begin with a survey of language proposals, including TinyDB, Cougar, Regions, and other more recent work, and will then examine a range of implementation issues that arise in such systems, including issues related to power efficiency, time synchronization, data collection and dissemination, fault-tolerance, and state management. After attending the tutorial, audience members should have a good understanding of the various systems in this space as well as an awareness of the technical issues that make building such systems difficult.\",\n \"Title: Demonstration of the TrajStore system\\nYear: 2009\\n\\nAbstract: The proliferation of GPS devices has led to a substantial interest in location based services. In particular, modern vehicles can generate an incredible amount of drive data. However, current storage systems are not optimized for storing and querying such large spatial-temporal data sets. In this demonstration, we show the performance of the TrajStore system, a dynamic storage system optimized for quickly accessing data in a particular spatial-temporal region. In particular, TrajStore uses a novel adaptive indexing technique that dynamically adjusts itself to co-locate spatially close trajectories on disk, as well as a number of compression techniques in the storage layer that significantly reduce access time for a given index cell. In this demonstration, we will store a set of real world taxi cab drive traces in TrajStore, and users will be able to query the data through a map based interface.\",\n \"Title: Java support for data-intensive systems: experiences building the telegraph dataflow system\\nYear: 2001\\n\\nAbstract: Database system designers have traditionally had trouble with the default services and interfaces provided by operating systems. In recent years, developers and enthusiasts have increasingly promoted Java as a serious platform for building data-intensive servers. Java provides a number of very helpful language features, as well as a full run-time environment reminiscent of a traditional operating system. This combination of features and community support raises the question of whether Java is better or worse at supporting data-intensive server software than a traditional operating system coupled with a weakly-typed language such as C or C++.In this paper, we summarize and discuss our experience building the Telegraph dataflow system in Java. We highlight some of the pleasures of coding with Java, and some of the pains of coding around Java in order to obtain good performance in a data-intensive server. For those issues that were painful, we present concrete suggestions for evolving Java's interfaces to better suit serious software systems development. We believe these experiences can provide insight for other designers to avoid pitfalls we encountered and to decide if Java is a suitable platform for their system.\",\n \"Title: Performance profiling with EndoScope, an acquisitional software monitoring framework\\nYear: 2008\\n\\nAbstract: We propose EndoScope, a software monitoring framework that allows users to pose declarative queries that monitor the state and performance of running programs. Unlike most existing monitoring tools, EndoScope is acquisitional, meaning that it only instruments the portions of the program that need to be monitored to answer queries. The use of a high level declarative language allows EndoScope to search for efficient physical instantiations of queries by applying a suite of optimizations, including control flow graph analysis, and traditional database query optimization techniques, such as predicate pushdown and join optimization, to minimize the number of program instrumentation points and overhead to the monitored program. Furthermore, a flexible, high level language and the ability to attach to running programs enable developers to build various program analysis and monitoring applications beyond traditional software profilers with EndoScope. We describe a prototype implementation of the EndoScope framework and a simple profiler for Java programs implemented with EndoScope. We show results from using our profiler on a collection of real-world programs, including a TPC-C implementation using the Derby database and the petstore application running on top of Tomcat application server. Our results show the benefit of our optimization framework and demonstrate that our declarative, acquisitional approach can yield program instrumentation overheads that are dramatically lower than conventional profiling tools (for example, when profiling the Derby Database running TPC-C, our system's overhead ranges from 1% to about 25%, whereas the fastest existing profiler we measured imposes a minimum overhead of about 30%.)\",\n \"Title: CarTel: a distributed mobile sensor computing system\\nYear: 2006\\n\\nAbstract: CarTel is a mobile sensor computing system designed to collect, process, deliver, and visualize data from sensors located on mobile units such as automobiles. A CarTel node is a mobile embedded computer coupled to a set of sensors. Each node gathers and processes sensor readings locally before delivering them to a central portal, where the data is stored in a database for further analysis and visualization. In the automotive context, a variety of on-board and external sensors collect data as users drive.CarTel provides a simple query-oriented programming interface, handles large amounts of heterogeneous data from sensors, and handles intermittent and variable network connectivity. CarTel nodes rely primarily on opportunistic wireless (e.g., Wi-Fi, Bluetooth) connectivity to the Internet, or to \\\"data mules\\\" such as other CarTel nodes, mobile phone flash memories, or USB keys-to communicate with the portal. CarTel applications run on the portal, using a delay-tolerant continuous query processor, ICEDB, to specify how the mobile nodes should summarize, filter, and dynamically prioritize data. The portal and the mobile nodes use a delay-tolerant network stack, CafNet, to communicat.CarTel has been deployed on six cars, running on a small scale in Boston and Seattle for over a year. It has been used to analyze commute times, analyze metropolitan Wi-Fi deployments, and for automotive diagnostics.\",\n \"Title: Query Processing in Sensor Networks\\nYear: 2003\\n\\nAbstract: Smart sensors are small, low-cost, wireless computing devices that sense information such as light and humidity at extremely high resolutions. Smart-sensor technology has enabled a broad range of ubiquitous computing applications, such as agricultural, industrial, and environmental monitoring. Because sensors collect and transmit information while managing limited power and radio bandwidth, traditional approaches for deploying these applications requires months of design and engineering time. A smart sensor query-processing architecture using database technology can, however, facilitate deployment of sensor networks greatly reducing programming effort and time-to-deployment for many such applications. The authors describe the design and implementation of an architecture to support the building of data-collection applications using sensors. Users specify the data of interest through simple, declarative queries, just as in a database system, and the infrastructure efficiently collects and processes the data within the sensor network.\",\n \"Title: Tolerating byzantine faults in transaction processing systems using commit barrier scheduling\\nYear: 2007\\n\\nAbstract: This paper describes the design, implementation, and evaluation of areplication scheme to handle Byzantine faults in transaction processing database systems. The scheme compares answers from queries and updates on multiple replicas which are unmodified, off-the-shelf systems, to provide a single database that is Byzantine fault tolerant. The scheme works when the replicas are homogeneous, but it also allows heterogeneous replication in which replicas come from different vendors. Heterogeneous replicas reduce the impact of bugs and security compromises because they are implemented independently and are thus less likely to suffer correlated failures. The main challenge in designing a replication scheme for transactionprocessing systems is ensuring that the different replicas execute transactions in equivalent serial orders while allowing a high degreeof concurrency. Our scheme meets this goal using a novel concurrency control protocol, commit barrier scheduling (CBS). We have implemented CBS in the context of a replicated SQL database, HRDB(Heterogeneous Replicated DB), which has been tested with unmodified production versions of several commercial and open source databases as replicas. Our experiments show an HRDB configuration that can tolerate one faulty replica has only a modest performance overhead(about 17% for the TPC-C benchmark). HRDB successfully masks several Byzantine faults observed in practice and we have used it to find a new bug in MySQL.\",\n \"Title: PCP: the personal commute portal\\nYear: 2008\\n\\nAbstract: The Personal Commute Portal (PCP) is a Web-based traffic information system that provides a good driving direction and personalized route recommendation using historical and real-time traffic data obtained by a vehicular sensor network.\",\n \"Title: A trigger-based middleware cache for ORMs\\nYear: 2011\\n\\nAbstract: Caching is an important technique in scaling storage for high-traffic web applications. Usually, building caching mechanisms involves significant effort from the application developer to maintain and invalidate data in the cache. In this work we present CacheGenie, a caching middleware which makes it easy for web application developers to use caching mechanisms in their applications. CacheGenie provides high-level caching abstractions for common query patterns in web applications based on Object-RelationalMapping (ORM) frameworks. Using these abstractions, the developer does not have to worry about managing the cache (e.g., insertion and deletion) or maintaining consistency (e.g., invalidation or updates) when writing application code. We design and implement CacheGenie in the popular Django web application framework, with PostgreSQL as the database backend and memcached as the caching layer. To automatically invalidate or update cached data, we use triggers inside the database. CacheGenie requires no modifications to PostgreSQL or memcached. To evaluate our prototype, we port several Pinax web applications to use our caching abstractions. Our results show that it takes little effort for application developers to use CacheGenie, and that CacheGenie improves throughput by 2-2.5× for read-mostly workloads in Pinax.\",\n \"Title: Demonstration of Qurk: a query processor for humanoperators\\nYear: 2011\\n\\nAbstract: Crowdsourcing technologies such as Amazon's Mechanical Turk (\\\"MTurk\\\") service have exploded in popularity in recent years. These services are increasingly used for complex human-reliant data processing tasks, such as labelling a collection of images, combining two sets of images to identify people that appear in both, or extracting sentiment from a corpus of text snippets. There are several challenges in designing a workflow that filters, aggregates, sorts and joins human-generated data sources. Currently, crowdsourcing-based workflows are hand-built, resulting in increasingly complex programs. Additionally, developers must hand-optimize tradeoffs among monetary cost, accuracy, and time to completion of results. These challenges are well-suited to a declarative query interface that allows developers to describe their worflow at a high level and automatically optimizes workflow and tuning parameters. In this demonstration, we will present Qurk, a novel query system that allows human-based processing for relational databases. The audience will interact with the system to build queries and monitor their progress. The audience will also see Qurk from an MTurk user's perspective, and complete several tasks to better understand how a query is processed.\",\n \"Title: XStream: a Signal-Oriented Data Stream Management System\\nYear: 2008\\n\\nAbstract: Sensors capable of sensing phenomena at high data rates on the order of tens to hundreds of thousands of samples per second are now widely deployed in many industrial, civil engineering, scientific, networking, and medical applications. In aggregate, these sensors easily generate several million samples per second that must be processed within milliseconds or seconds. The computation required includes both signal processing and event stream processing. XStream is a stream processing system for such applications. XStream introduces a new data type, the signal segment, which allows applications to manipulate isochronous (regularly spaced in time) collections of sensor samples more conveniently and efficiently than the asynchronous representation used in previous work. XStream includes a memory manager and scheduler optimizations tuned for processing signal segments at high speeds. In benchmark comparisons, we show that XStream outperforms a leading commercial stream processing system by more than three orders of magnitude. On one application, the commercial system processed 72.7 Ksamples/sec, while XStream processed 97.6 Msamples/sec.\",\n \"Title: CARTILAGE: adding flexibility to the Hadoop skeleton\\nYear: 2013\\n\\nAbstract: Modern enterprises have to deal with a variety of analytical queries over very large datasets. In this respect, Hadoop has gained much popularity since it scales to thousand of nodes and terabytes of data. However, Hadoop suffers from poor performance, especially in I/O performance. Several works have proposed alternate data storage for Hadoop in order to improve the query performance. However, many of these works end up making deep changes in Hadoop or HDFS. As a result, they are (i) difficult to adopt by several users, and (ii) not compatible with future Hadoop releases. In this paper, we present CARTILAGE, a comprehensive data storage framework built on top of HDFS. CARTILAGE allows users full control over their data storage, including data partitioning, data replication, data layouts, and data placement. Furthermore, CARTILAGE can be layered on top of an existing HDFS installation. This means that Hadoop, as well as other query engines, can readily make use of CARTILAGE. We describe several use-cases of CARTILAGE and propose to demonstrate the flexibility and efficiency of CARTILAGE through a set of novel scenarios.\",\n \"Title: The pothole patrol: using a mobile sensor network for road surface monitoring\\nYear: 2008\\n\\nAbstract: This paper investigates an application of mobile sensing: detecting and reporting the surface conditions of roads. We describe a system and associated algorithms to monitor this important civil infrastructure using a collection of sensor-equipped vehicles. This system, which we call the Pothole Patrol (P2), uses the inherent mobility of the participating vehicles, opportunistically gathering data from vibration and GPS sensors, and processing the data to assess road surface conditions. We have deployed P2 on 7 taxis running in the Boston area. Using a simple machine-learning approach, we show that we are able to identify potholes and other severe road surface anomalies from accelerometer data. Via careful selection of training data and signal features, we have been able to build a detector that misidentifies good road segments as having potholes less than 0.2% of the time. We evaluate our system on data from thousands of kilometers of taxi drives, and show that it can successfully detect a number of real potholes in and around the Boston area. After clustering to further reduce spurious detections, manual inspection of reported potholes shows that over 90% contain road anomalies in need of repair.\",\n \"Title: An integrated approach to recovery and high availability in an updatable, distributed data warehouse\\nYear: 2006\\n\\nAbstract: Any highly available data warehouse will use some form of data replication to tolerate machine failures. In this paper, we demonstrate that we can leverage this data redundancy to build an integrated approach to recovery and high availability. Our approach, called HARBOR, revives a crashed site by querying remote, online sites for missing updates and uses timestamps to determine which tuples need to be copied or updated. HARBOR does not require a stable log, recovers without quiescing the system, allows replicated data to be stored non-identically, and is simpler than a log-based recovery algorithm.We compare the runtime overhead and recovery performance of HARBOR to those of two-phase commit and ARIES, the gold standard for log-based recovery, on a three-node distributed database system. Our experiments demonstrate that HARBOR suffers lower runtime overhead, has recovery performance comparable to ARIES's, and can tolerate the fault of a worker and efficiently bring it back online.\",\n \"Title: MDCC: multi-data center consistency\\nYear: 2013\\n\\nAbstract: Replicating data across multiple data centers allows using data closer to the client, reducing latency for applications, and increases the availability in the event of a data center failure. MDCC (Multi-Data Center Consistency) is an optimistic commit protocol for geo-replicated transactions, that does not require a master or static partitioning, and is strongly consistent at a cost similar to eventually consistent protocols. MDCC takes advantage of Generalized Paxos for transaction processing and exploits commutative updates with value constraints in a quorum-based system. Our experiments show that MDCC outperforms existing synchronous transactional replication protocols, such as Megastore, by requiring only a single message round-trip in the normal operational case independent of the master-location and by scaling linearly with the number of machines as long as transaction conflict rates permit.\",\n \"Title: Correlation maps: a compressed access method for exploiting soft functional dependencies\\nYear: 2009\\n\\nAbstract: In relational query processing, there are generally two choices for access paths when performing a predicate lookup for which no clustered index is available. One option is to use an unclustered index. Another is to perform a complete sequential scan of the table. Many analytical workloads do not benefit from the availability of unclustered indexes; the cost of random disk I/O becomes prohibitive for all but the most selective queries. It has been observed that a secondary index on an unclustered attribute can perform well under certain conditions if the unclustered attribute is correlated with a clustered index attribute [4]. The clustered index will co-locate values and the correlation will localize access through the unclustered attribute to a subset of the pages. In this paper, we show that in a real application (SDSS) and widely used benchmark (TPC-H), there exist many cases of attribute correlation that can be exploited to accelerate queries. We also discuss a tool that can automatically suggest useful pairs of correlated attributes. It does so using an analytical cost model that we developed, which is novel in its awareness of the effects of clustering and correlation. Furthermore, we propose a data structure called a Correlation Map (CM) that expresses the mapping between the correlated attributes, acting much like a secondary index. The paper also discusses how bucketing on the domains of both attributes in the correlated attribute pair can dramatically reduce the size of the CM to be potentially orders of magnitude smaller than that of a secondary B+Tree index. This reduction in size allows us to create a large number of CMs that improve performance for a wide range of queries. The small size also reduces maintenance costs as we demonstrate experimentally.\",\n \"Title: Accurate, low-energy trajectory mapping for mobile devices\\nYear: 2011\\n\\nAbstract: CTrack is an energy-efficient system for trajectory mapping using raw position tracks obtained largely from cellular base station fingerprints. Trajectory mapping, which involves taking a sequence of raw position samples and producing the most likely path followed by the user, is an important component in many location-based services including crowd-sourced traffic monitoring, navigation and routing, and personalized trip management. Using only cellular (GSM) fingerprints instead of power-hungry GPS and WiFi radios, the marginal energy consumed for trajectory mapping is zero. This approach is non-trivial because we need to process streams of highly inaccurate GSM localization samples (average error of over 175 meters) and produce an accurate trajectory. CTrack meets this challenge using a novel two-pass Hidden Markov Model that sequences cellular GSM fingerprints directly without converting them to geographic coordinates, and fuses data from low-energy sensors available on most commodity smart-phones, including accelerometers (to detect movement) and magnetic compasses (to detect turns). We have implemented CTrack on the Android platform, and evaluated it on 126 hours (1,074 miles) of real driving traces in an urban environment. We find that CTrack can retrieve over 75% of a user's drive accurately in the median. An important by-product of CTrack is that even devices with no GPS or WiFi (constituting a significant fraction of today's phones) can contribute and benefit from accurate position data.\",\n \"Title: Wishbone: profile-based partitioning for sensornet applications\\nYear: 2009\\n\\nAbstract: The ability to partition sensor network application code across sensor nodes and backend servers is important for running complex, data-intensive applications on sensor platforms that have CPU, energy, and bandwidth limitations. This paper presents Wishbone, a system that takes a dataflow graph of operators and produces an optimal partitioning. With Wishbone, users can run the same program on a range of sensor platforms, including TinyOS motes, smartphones running JavaME, and the iPhone. The resulting program partitioning will in general be different in each case, reflecting the different node capabilities. Wishbone uses profiling to determine how each operator in the dataflow graph will actually perform on sample data, without requiring cumbersome user annotations. Its partitioning algorithm models the problem as an integer linear program that minimizes a linear combination of network bandwidth and CPU load and uses program structure to solve the problem efficiently in practice. Our results on a speech detection application show that the system can quickly identify good trade-offs given limitations in CPU and network capacity.\",\n \"Title: The Claremont report on database research\\nYear: 2008\\n\\nAbstract: In late May, 2008, a group of database researchers, architects, users and pundits met at the Claremont Resort in Berkeley, California to discuss the state of the research field and its impacts on practice. This was the seventh meeting of this sort in twenty years, and was distinguished by a broad consensus that we are at a turning point in the history of the field, due both to an explosion of data and usage scenarios, and to major shifts in computing hardware and platforms. Given these forces, we are at a time of opportunity for research impact, with an unusually large potential for influential results across computing, the sciences and society. This report details that discussion, and highlights the group's consensus view of new focus areas, including new database engine architectures, declarative programming languages, the interplay of structured and unstructured data, cloud data services, and mobile and virtual worlds. We also report on discussions of the community's growth, including suggestions for changes in community processes to move the research agenda forward, and to enhance impact on a broader audience.\",\n \"Title: WaveScope: a signal-oriented data stream management system\\nYear: 2006\\n\\nAbstract: WaveScope is a data management and continuous sensor data system that integrates relational database and signal processing operations into a single system. WaveScope is motivated by a large number of signal-oriented streaming sensor applications, such as: preventive maintenance of industrial equipment; detection of fractures and ruptures in various structures; in situ animal behavior studies using acoustic sensing; network traffic analysis; and medical applications such as anomaly detection in EKGs. These target applications use a variety of embedded sensors, each sampling at fine resolution and producing data at high rates ranging from hundreds to hundreds of thousands of samples per second. Though there has been some work on applications in the sensor network community that do this kind of signal processing (for example, shooter localization [5], industrial equipment monitoring [4], and urban infrastructure monitoring [2]), these applications are typically custombuilt and do not provide reusable high-level programming framework suitable for easily building new signal processing applications with similar functionality. This poster shows how WaveScope supports these types of application in a single, unified framework, providing both high run-time performance and easy application development.\",\n \"Title: Speedy transactions in multicore in-memory databases\\nYear: 2013\\n\\nAbstract: Silo is a new in-memory database that achieves excellent performance and scalability on modern multicore machines. Silo was designed from the ground up to use system memory and caches efficiently. For instance, it avoids all centralized contention points, including that of centralized transaction ID assignment. Silo's key contribution is a commit protocol based on optimistic concurrency control that provides serializability while avoiding all shared-memory writes for records that were only read. Though this might seem to complicate the enforcement of a serial order, correct logging and recovery is provided by linking periodically-updated epochs with the commit protocol. Silo provides the same guarantees as any serializable database without unnecessary scalability bottlenecks or much additional latency. Silo achieves almost 700,000 transactions per second on a standard TPC-C workload mix on a 32-core machine, as well as near-linear scalability. Considered per core, this is several times higher than previously reported results.\",\n \"Title: Supporting Aggregate Queries Over Ad-Hoc Wireless Sensor Networks\\nYear: 2002\\n\\nAbstract: We show how the database community's notion of a generic query interface for data aggregation can be applied to ad-hoc networks of sensor devices. As has been noted in the sensor network literature, aggregation is important as a data reduction tool; networking approaches, however, have focused on application specific solutions, whereas our in-network aggregation approach is driven by a general purpose, SQL-style interface that can execute queries over any type of sensor data while providing opportunities for significant optimization. We present a variety of techniques to improve the reliability and performance of our solution. We also show how grouped aggregates can be efficiently computed and offer a comparison to related systems and database projects.\",\n \"Title: Scorpion: explaining away outliers in aggregate queries\\nYear: 2013\\n\\nAbstract: Database users commonly explore large data sets by running aggregate queries that project the data down to a smaller number of points and dimensions, and visualizing the results. Often, such visualizations will reveal outliers that correspond to errors or surprising features of the input data set. Unfortunately, databases and visualization systems do not provide a way to work backwards from an outlier point to the common properties of the (possibly many) unaggregated input tuples that correspond to that outlier. We propose Scorpion, a system that takes a set of user-specified outlier points in an aggregate query result as input and finds predicates that explain the outliers in terms of properties of the input tuples that are used to compute the selected outlier results. Specifically, this explanation identifies predicates that, when applied to the input data, cause the outliers to disappear from the output. To find such predicates, we develop a notion of influence of a predicate on a given output, and design several algorithms that efficiently search for maximum influence predicates over the input data. We show that these algorithms can quickly find outliers in two real data sets (from a sensor deployment and a campaign finance data set), and run orders of magnitude faster than a naive search algorithm while providing comparable quality on a synthetic data set.\",\n \"Title: Improving wireless network performance using sensor hints\\nYear: 2011\\n\\nAbstract: With the proliferation of mobile wireless devices such as smartphones and tablets that are used in a wide range of locations and movement conditions, it has become important for wireless protocols to adapt to different settings over short periods of time. Network protocols that perform well in static settings where channel conditions are relatively stable tend to perform poorly in mobile settings where channel conditions change rapidly, and vice versa. To adapt to the conditions under which communication is occurring, we propose the use of external sensor hints to augment network protocols. Commodity smartphones and tablet devices come equipped with a variety of sensors, including GPS, accelerometers, magnetic compasses, and gyroscopes, which can provide hints about the device's mobility state and its operating environment. We present a wireless protocol architecture that integrates sensor hints in adaptation algorithms. We validate the idea and architecture by implementing and evaluating sensor-augmented wireless protocols for bit rate adaptation, access point association, neighbor maintenance in mobile mesh networks, and path selection in vehicular networks.\",\n \"Title: Thinking Big About Tiny Databases\\nYear: 2007\\n\\nAbstract: Work on early tiny database systems, like TinyDB (17) and Cougar (23) has shown that a declar- ative approach can provide a powerful and easy to use interface for collecting data from static sensor networks. These early systems, however, have significant limitations; in particular, they are useful only for low-rate data collection applications on static sensor networks and they don't integrate well with existing database and IT tools. In this paper, we discuss recent research that has addressed these limi- tations, showing that similar \\\"tiny database thinking\\\" can provide solutions to much bigger problems, including network protocol specification and mobile and high data rate signal-oriented data processing.\",\n \"Title: Stochastic motion planning and applications to traffic\\nYear: 2011\\n\\nAbstract: This paper presents a stochastic motion planning algorithm and its application to traffic navigation. The algorithm copes with the uncertainty of road traffic conditions by stochastic modeling of travel delay on road networks. The algorithm determines paths between two points that optimize a cost function of the delay probability distribution. It c an be used to find paths that maximize the probability of reaching a destination within a partic ular travel deadline. For such problems, standard shortest-path algorithms don't work because the optimal substructure property doesn't hold. We evaluate our algorithm using bo th simulations and real- world drives, using delay data gathered from a set of taxis equipped with GPS sensors and a wireless network. Our algorithm can be integrated into on-board navigation systems as well as route-finding Web sites, providing drivers with good paths that meet th eir desired goals. This paper presents and evaluates an algorithm for planning the motion of vehicles (autonomous or human-driven) on roadways in the face of traffic delays. Rather than model road delays statically, as in current on-board navigation systems and Web- based mapping services, our algorithm uses past observations of actual delays on road segments to model these delays as probability distributions. The algorithm min- imizes a user-specified cost function of the delay distribut ion. We investigate a few cost functions in detail, particularly one that is equivale nt to maximizing the likeli- hood of reaching a destination within a specified travel dead line. Our work provides a planning system that can be used by robots as well as hu- man drivers. The system is a useful addition to on-board navigation systems us- ing computer-aided automation to provide good paths that meet desired travel goals (e.g., \\\"when should you leave, and what path should you take, to reach the airport by 8am with high probability?\\\"); it is also a worthwhile addition to Web-based map- ping services. We view the incorporation of traffic-aware pa th computation as an important practical addition in the rapid trend toward computer-assisted driving and autonomous decision-making in vehicles. Traffic congestion is clearly a serious problem: a recent sur vey (11) estimates that the annual nationwide cost of traffic congestion is $78 billi on, including 4.2 billion hours in lost time and 2.9 billion gallons in wasted fuel. Drivers today have little knowledge of historic and real-time traffic congestion on th e paths they drive, and\",\n \"Title: H-store: a high-performance, distributed main memory transaction processing system\\nYear: 2008\\n\\nAbstract: Our previous work has shown that architectural and application shifts have resulted in modern OLTP databases increasingly falling short of optimal performance [10]. In particular, the availability of multiple-cores, the abundance of main memory, the lack of user stalls, and the dominant use of stored procedures are factors that portend a clean-slate redesign of RDBMSs. This previous work showed that such a redesign has the potential to outperform legacy OLTP databases by a significant factor. These results, however, were obtained using a bare-bones prototype that was developed just to demonstrate the potential of such a system. We have since set out to design a more complete execution platform, and to implement some of the ideas presented in the original paper. Our demonstration presented here provides insight on the development of a distributed main memory OLTP database and allows for the further study of the challenges inherent in this operating environment.\",\n \"Title: BlinkDB: queries with bounded errors and bounded response times on very large data\\nYear: 2013\\n\\nAbstract: In this paper, we present BlinkDB, a massively parallel, approximate query engine for running interactive SQL queries on large volumes of data. BlinkDB allows users to trade-off query accuracy for response time, enabling interactive queries over massive data by running queries on data samples and presenting results annotated with meaningful error bars. To achieve this, BlinkDB uses two key ideas: (1) an adaptive optimization framework that builds and maintains a set of multi-dimensional stratified samples from original data over time, and (2) a dynamic sample selection strategy that selects an appropriately sized sample based on a query's accuracy or response time requirements. We evaluate BlinkDB against the well-known TPC-H benchmarks and a real-world analytic workload derived from Conviva Inc., a company that manages video distribution over the Internet. Our experiments on a 100 node cluster show that BlinkDB can answer queries on up to 17 TBs of data in less than 2 seconds (over 200 x faster than Hive), within an error of 2-10%.\",\n \"Title: A comparison of approaches to large-scale data analysis\\nYear: 2009\\n\\nAbstract: There is currently considerable enthusiasm around the MapReduce (MR) paradigm for large-scale data analysis [17]. Although the basic control flow of this framework has existed in parallel SQL database management systems (DBMS) for over 20 years, some have called MR a dramatically new computing model [8, 17]. In this paper, we describe and compare both paradigms. Furthermore, we evaluate both kinds of systems in terms of performance and development complexity. To this end, we define a benchmark consisting of a collection of tasks that we have run on an open source version of MR as well as on two parallel DBMSs. For each task, we measure each system's performance for various degrees of parallelism on a cluster of 100 nodes. Our results reveal some interesting trade-offs. Although the process to load data into and tune the execution of parallel DBMSs took much longer than the MR system, the observed performance of these DBMSs was strikingly better. We speculate about the causes of the dramatic performance difference and consider implementation concepts that future systems should take from both kinds of architectures.\",\n \"Title: Integrating compression and execution in column-oriented database systems\\nYear: 2006\\n\\nAbstract: Column-oriented database system architectures invite a re-evaluation of how and when data in databases is compressed. Storing data in a column-oriented fashion greatly increases the similarity of adjacent records on disk and thus opportunities for compression. The ability to compress many adjacent tuples at once lowers the per-tuple cost of compression, both in terms of CPU and space overheads.In this paper, we discuss how we extended C-Store (a column-oriented DBMS) with a compression sub-system. We show how compression schemes not traditionally used in row-oriented DBMSs can be applied to column-oriented systems. We then evaluate a set of compression schemes and show that the best scheme depends not only on the properties of the data but also on the nature of the query workload.\",\n \"Title: Beyond average: toward sophisticated sensing with queries\\nYear: 2003\\n\\nAbstract: High-level query languages are an attractive interface for sensor networks, potentially relieving application programmers from the burdens of distributed, embedded programming. In research to date, however, the proposed applications of such interfaces have been limited to simple data collection and aggregation schemes. In this paper, we present initial results that extend the TinyDB sensornet query engine to support more sophisticated data analyses, focusing on three applications: topographic mapping, wavelet-based compression, and vehicle tracking. We use these examples to motivate the feasibility of implementing sophisticated sensing applications in a query-based system, and present some initial results and research questions raised by this agenda.\",\n \"Title: Inferring SQL Queries Using Program Synthesis\\nYear: 2012\\n\\nAbstract: Developing high-performance applications that interact with databases is a difficult task, as developers need to understand both the details of the language in which their applications are written in, and also the intricacies of the relational model. One popular solution to this problem is the use of object-relational mapping (ORM) libraries that provide transparent access to the database using the same language that the application is written in. Unfortunately, using such frameworks can easily lead to applications with poor performance because developers often end up implementing relational operations in application code, and doing so usually does not take advantage of the optimized implementations of relational operations, efficient query plans, or push down of predicates that database systems provide. In this paper we present QBS, an algorithm that automatically identifies fragments of application logic that can be pushed into SQL queries. The QBS algorithm works by automatically synthesizing invariants and postconditions for the original code fragment. The postconditions and invariants are expressed using a theory of ordered relations that allows us to reason precisely about the contents and order of the records produced even by complex code fragments that compute joins and aggregates. The theory is close in expressiveness to SQL, so the synthesized postconditions can be readily translated to SQL queries. Using 40 code fragments extracted from over 120k lines of open-source code written using the Java Hibernate ORM, we demonstrate that our approach can convert a variety of imperative constructs into relational specifications.\",\n \"Title: Code in the air: simplifying sensing and coordination tasks on smartphones\\nYear: 2012\\n\\nAbstract: A growing class of smartphone applications are tasking applications that run continuously, process data from sensors to determine the user's context (such as location) and activity, and optionally trigger certain actions when the right conditions occur. Many such tasking applications also involve coordination between multiple users or devices. Example tasking applications include location-based reminders, changing the ring-mode of a phone automatically depending on location, notifying when friends are nearby, disabling WiFi in favor of cellular data when moving at more than a certain speed outdoors, automatically tracking and storing movement tracks when driving, and inferring the number of steps walked each day. Today, these applications are non-trivial to develop, although they are often trivial for end users to state. Additionally, simple implementations can consume excessive amounts of energy. This paper proposes Code in the Air (CITA), a system which simplifies the rapid development of tasking applications. It enables non-expert end users to easily express simple tasks on their phone, and more sophisticated developers to write code for complex tasks by writing purely server-side scripts. CITA provides a task execution framework to automatically distribute and coordinate tasks, energy-efficient modules to infer user activities and compose them, and a push communication service for mobile devices that overcomes some shortcomings in existing push services.\",\n \"Title: Report on the Fourth International Workshop on Data Management for Sensor Networks (DMSN 2007)\\nYear: 2007\\n\\nAbstract: Sensor networks enable an unprecedented level of access to the physical world, and hold tremendous potential to revolutionize many application domains. Research on sensor networks spans many areas of computer science, and there are now major conferences, e.g., IPSN and SenSys, devoted to sensor networks. However, there is no focused forum for discussion of early and innovative work on data management in sensor networks. The International Workshop on Data Management for Sensor Networks (DMSN), inaugurated in 2004, aims to fill this significant gap in the database and sensor network communities.\",\n \"Title: Top-k queries on uncertain data: on score distribution and typical answers\\nYear: 2009\\n\\nAbstract: Uncertain data arises in a number of domains, including data integration and sensor networks. Top-k queries that rank results according to some user-defined score are an important tool for exploring large uncertain data sets. As several recent papers have observed, the semantics of top-k queries on uncertain data can be ambiguous due to tradeoffs between reporting high-scoring tuples and tuples with a high probability of being in the resulting data set. In this paper, we demonstrate the need to present the score distribution of top-k vectors to allow the user to choose between results along this score-probability dimensions. One option would be to display the complete distribution of all potential top-k tuple vectors, but this set is too large to compute. Instead, we propose to provide a number of typical vectors that effectively sample this distribution. We propose efficient algorithms to compute these vectors. We also extend the semantics and algorithms to the scenario of score ties, which is not dealt with in the previous work in the area. Our work includes a systematic empirical study on both real dataset and synthetic datasets.\",\n \"Title: PAQ: time series forecasting for approximate query answering in sensor networks\\nYear: 2006\\n\\nAbstract: In this paper, we present a method for approximating the values of sensors in a wireless sensor network based on time series forecasting. More specifically, our approach relies on autoregressive models built at each sensor to predict local readings. Nodes transmit these local models to a sink node, which uses them to predict sensor values without directly communicating with sensors. When needed, nodes send information about outlier readings and model updates to the sink. We show that this approach can dramatically reduce the amount of communication required to monitor the readings of all sensors in a network, and demonstrate that our approach provides provably-correct, user-controllable error bounds on the predicted values of each sensor.\",\n \"Title: TAG: a Tiny AGgregation service for ad-hoc sensor networks\\nYear: 2002\\n\\nAbstract: We present the Tiny AGgregation (TAG) service for aggregation in low-power, distributed, wireless environments. TAG allows users to express simple, declarative queries and have them distributed and executed efficiently in networks of low-power, wireless sensors. We discuss various generic properties of aggregates, and show how those properties affect the performance of our in network approach. We include a performance study demonstrating the advantages of our approach over traditional centralized, out-of-network methods, and discuss a variety of optimizations for improving the performance and fault tolerance of the basic solution.\",\n \"Title: Using program synthesis for social recommendations\\nYear: 2012\\n\\nAbstract: This paper presents a new approach to select events of interest to users in a social media setting where events are generated from mobile devices. We argue that the problem is best solved by inductive learning, where the goal is to first generalize from the users' expressed \\\"likes\\\" and \\\"dislikes\\\" of specific events, then to produce a program that can be used to collect only data of interest. The key contribution of this paper is a new algorithm that combines machine learning techniques with program synthesis technology to learn users' preferences. We show that when compared with the more standard approaches, our new algorithm provides up to order-of-magnitude reductions in model training time, and significantly higher prediction accuracies for our target application.1\",\n \"Title: HYRISE: a main memory hybrid storage engine\\nYear: 2010\\n\\nAbstract: In this paper, we describe a main memory hybrid database system called HYRISE, which automatically partitions tables into vertical partitions of varying widths depending on how the columns of the table are accessed. For columns accessed as a part of analytical queries (e.g., via sequential scans), narrow partitions perform better, because, when scanning a single column, cache locality is improved if the values of that column are stored contiguously. In contrast, for columns accessed as a part of OLTP-style queries, wider partitions perform better, because such transactions frequently insert, delete, update, or access many of the fields of a row, and co-locating those fields leads to better cache locality. Using a highly accurate model of cache misses, HYRISE is able to predict the performance of different partitionings, and to automatically select the best partitioning using an automated database design algorithm. We show that, on a realistic workload derived from customer applications, HYRISE can achieve a 20% to 400% performance improvement over pure all-column or all-row designs, and that it is both more scalable and produces better designs than previous vertical partitioning approaches for main memory systems.\",\n \"Title: CrowdDB: query processing with the VLDB crowd\\nYear: 2011\\n\\nAbstract: AbstractDatabases often give incorrect answers when data are missing or semantic understanding of the data is required. Processing such queries requires human input for providing the missing information, for performing computationally difficult functions, and for matching, ranking, or aggregating results based on fuzzy criteria. In this demo we present CrowdDB, a hybrid database system that automatically uses crowdsourcing to integrate human input for processing queries that a normal database system cannot answer.CrowdDB uses SQL both as a language to ask complex queries and as a way to model data stored electronically and provided by human input. Furthermore, queries are automatically compiled and optimized. Special operators provide user interfaces in order to integrate and cleanse human input. Currently CrowdDB supports two crowdsourcing platforms: Amazon Mechanical Turk and our own mobile phone platform. During the demo, the mobile platform will allow the VLDB crowd to participate as workers and help answer otherwise impossible queries.\",\n \"Title: Data Management Issues in Disconnected Sensor Networks\\nYear: 2004\\n\\nAbstract: The possibility of disconnection is one of the fundamental new network- ing problems presented by sensor networks. The goal of this paper is to address the problem of result collection in periodically disconnectedsensor networks, focusing, in particular, on opportunities for in-network processing. Our hypothesis is that, through careful augmentation of the networking layer underneath the declarative query proces- sor, it will be possible to expose information that will make the query processor able to adapt to and handle disconnections.\",\n \"Title: TOADS: A Two-Dimensional Open-Ended Architectural Database System\\nYear: 2001\\n\\nAbstract: The TOADS system is an innovative tool for building interior-space virtual environments (VEs) in two dimensions. Existing VE design tools typically operate in three dimensions, which makes it difficult to manipulate objects on the inherently two-dimensional computer screen. TOADS allows nearly the same functionality as those three-dimensional systems in an easy-to-use, two-dimensional environment. Users edit and enhance DXF floorplans with height and texture information. The software includes an inference engine that automatically identifies doors in the floorplan and generates openable polygons in the final environment. It also includes a sophisticated mechanism for embedding complex textures, such as transparent windows, at arbitrary heights in wall polygons. The entire interface is integrated with software that drives a custom texture-acquisition device. This device consists of a rack-mounted camera that captures narrow bands of textures and tiles them together to form long, continuous swaths of texture. This paper summarizes these tools and their function, and presents examples of environments that were generated with them.\",\n \"Title: REED: robust, efficient filtering and event detection in sensor networks\\nYear: 2005\\n\\nAbstract: This paper presents a set of algorithms for efficiently evaluating join queries over static data tables in sensor networks. We describe and evaluate three algorithms that take advantage of distributed join techniques. Our algorithms are capable of running in limited amounts of RAM, can distribute the storage burden over groups of nodes, and are tolerant to dropped packets and node failures. REED is thus suitable for a wide range of event-detection applications that traditional sensor network database and data collection systems cannot be used to implement.\",\n \"Title: Icedb: Intermittently-Connected Continuous Query Processing\\nYear: 2007\\n\\nAbstract: Current distributed database and stream processing systems assume that the network connecting nodes in the data Processor is \\\"always on,\\\" and that the absence of a network connection is a fault that needs to be masked to avoid failure. Several emerging wireless sensor network applications must cope with a combination of node mobility (e.g., sensors on moving cars) and high data rates (media-rich sensors capturing videos, images, sounds, etc.). Due to their mobility, these sensor networks display intermittent and variable network connectivity, and often have to deliver large quantities of data relative to the bandwidth available during periods of connectivity.This paper describes ICEDB (Intermittently Connected Embedded Database), a continuous query processing system for intermittently connected mobile sensor networks. ICEDB incorporates two key ideas: (1) a delay-tolerant continuous query processor, coordinated by a central server and distributed across the mobile nodes, and (2) algorithms for Prioritizing certain query results to improve application-defined \\\"utility\\\" metrics. We describe the results of several experiments that use data collected from a small deployed network of six cars driving in and around Boston and Seattle.\",\n \"Title: A measurement-based analysis of the interaction between network layers in TinyOS\\nYear: 2006\\n\\nAbstract: There have been a number of recent proposals for link and network-layer protocols in the sensor networking literature, each of which claims to be superior to other approaches. However, a proposal for a networking protocol at a given layer in the stack is typically evaluated in the context of a single set of carefully selected protocols at other layers. Because of the limited data available about interactions between different protocols at various layers of the stack, it is difficult for developers of sensor network applications to select from amongst the range of alternative sensor networking protocols. This paper evaluates the interaction between several protocols at the MAC and network layers measuring their performance in terms of end-to-end throughput and loss on a large testbed. We identify some common sources of poor performance; based on this experience, we propose a set of design principles for the designers of future interfaces.\",\n \"Title: Speeding up database applications with Pyxis\\nYear: 2013\\n\\nAbstract: We propose to demonstrate Pyxis, a system that optimizes database applications by pushing computation to the database server. Our system applies program analysis techniques to the application source code to determine pieces of application logic that should be moved to the database server to improve performance. This frees the developer from the need to understand the intricacies of database operations or learn a new programming language for stored procedures. In addition, by dynamically monitoring resource utilization on the database server, Pyxis can migrate computation between application and database in response to workload changes. Our previous experiments have shown that Pyxis can decrease latency up to 3x for transactional applications, and improve throughput up to 1.7x when compared to a standard implementation using embedded SQL statements in application logic. We will demonstrate these capabilities via a visualization of real-time performance as well as an interactive code partitioning tool we have developed.\",\n \"Title: TelegraphCQ: Continuous Dataflow Processing for an Uncertain World.\\nYear: 2003\\n\\nAbstract: Increasingly pervasive networks are leading towards a world where data is constantly in motion. In such a world, conventional techniques for query processing, which were developed under the assumption of a far more static and predictable computational environment, will not be sufficient. Instead, query processors based on adaptive dataflow will be necessary. The Telegraph project has developed a suite of novel technologies for continuously adaptive query processing. The next generation Telegraph system, called TelegraphCQ, is focused on meeting the challenges that arise in handling large streams of continuous queries over high-volume, highly-variable data streams. In this paper, we describe the system architecture and its underlying technology, and report on our ongoing implementation effort, which leverages the PostgreSQL open source code base. We also discuss open issues and our research agenda.\",\n \"Title: VERTEXICA: Your Relational Friend for Graph Analytics!\\nYear: 2014\\n\\nAbstract: In this paper, we present Vertexica, a graph analytics tools on top of a relational database, which is user friendly and yet highly efficient. Instead of constraining programmers to SQL, Vertexica offers a popular vertex-centric query interface, which is more natural for analysts to express many graph queries. The programmers simply provide their vertex-compute functions and Vertexica takes care of efficiently executing them in the standard SQL engine. The advantage of using Vertexica is its ability to leverage the relational features and enable much more sophisticated graph analysis. These include expressing graph algorithms which are difficult in vertex-centric but straightforward in SQL and the ability to compose end-to-end data processing pipelines, including pre- and post- processing of graphs as well as combining multiple algorithms for deeper insights. Vertexica has a graphical user interface and we outline several demonstration scenarios including, interactive graph analysis, complex graph analysis, and continuous and time series analysis.\",\n \"Title: SeeDB: automatically generating query visualizations\\nYear: 2014\\n\\nAbstract: Data analysts operating on large volumes of data often rely on visualizations to interpret the results of queries. However, finding the right visualization for a query is a laborious and time-consuming task. We demonstrate SeeDB, a system that partially automates this task: given a query, SeeDB explores the space of all possible visualizations, and automatically identifies and recommends to the analyst those visualizations it finds to be most \\\\\\\"interesting\\\\\\\" or \\\\\\\"useful\\\\\\\". In our demonstration, conference attendees will see SeeDB in action for a variety of queries on multiple real-world datasets.\",\n \"Title: Scaling Up Crowd-Sourcing to Very Large Datasets: A Case for Active Learning.\\nYear: 2014\\n\\nAbstract: Crowd-sourcing has become a popular means of acquiring labeled data for many tasks where humans are more accurate than computers, such as image tagging, entity resolution, and sentiment analysis. However, due to the time and cost of human labor, solutions that rely solely on crowd-sourcing are often limited to small datasets (i.e., a few thousand items). This paper proposes algorithms for integrating machine learning into crowd-sourced databases in order to combine the accuracy of human labeling with the speed and cost-effectiveness of machine learning classifiers. By using active learning as our optimization strategy for labeling tasks in crowd-sourced databases, we can minimize the number of questions asked to the crowd, allowing crowd-sourced applications to scale (i.e., label much larger datasets at lower costs). Designing active learning algorithms for a crowd-sourced database poses many practical challenges: such algorithms need to be generic, scalable, and easy to use, even for practitioners who are not machine learning experts. We draw on the theory of nonparametric bootstrap to design, to the best of our knowledge, the first active learning algorithms that meet all these requirements. Our results, on 3 real-world datasets collected with Amazons Mechanical Turk, and on 15 UCI datasets, show that our methods on average ask 1--2 orders of magnitude fewer questions than the baseline, and 4.5--44× fewer than existing active learning algorithms.\",\n \"Title: Rapid sampling for visualizations with ordering guarantees\\nYear: 2014\\n\\nAbstract: Visualizations are frequently used as a means to understand trends and gather insights from datasets, but often take a long time to generate. In this paper, we focus on the problem of rapidly generating approximate visualizations while preserving crucial visual properties of interest to analysts. Our primary focus will be on sampling algorithms that preserve the visual property of ordering; our techniques will also apply to some other visual properties. For instance, our algorithms can be used to generate an approximate visualization of a bar chart very rapidly, where the comparisons between any two bars are correct. We formally show that our sampling algorithms are generally applicable and provably optimal in theory, in that they do not take more samples than necessary to generate the visualizations with ordering guarantees. They also work well in practice, correctly ordering output groups while taking orders of magnitude fewer samples and much less time than conventional sampling schemes.\",\n \"Title: S-Store: a streaming NewSQL system for big velocity applications\\nYear: 2014\\n\\nAbstract: First-generation streaming systems did not pay much attention to state management via ACID transactions (e.g., [3, 4]). S-Store is a data management system that combines OLTP transactions with stream processing. To create S-Store, we begin with H-Store, a main-memory transaction processing engine, and add primitives to support streaming. This includes triggers and transaction workflows to implement push-based processing, windows to provide a way to bound the computation, and tables with hidden state to implement scoping for proper isolation. This demo explores the benefits of this approach by showing how a naïve implementation of our benchmarks using only H-Store can yield incorrect results. We also show that by exploiting push-based semantics and our implementation of triggers, we can achieve significant improvement in transaction throughput. We demo two modern applications: (i) leaderboard maintenance for a version of \\\\\\\"American Idol\\\\\\\", and (ii) a city-scale bicycle rental scenario.\",\n \"Title: DataHub: Collaborative Data Science & Dataset Version Management at Scale.\\nYear: 2014\\n\\nAbstract: Relational databases have limited support for data collaboration, where teams collaboratively curate and analyze large datasets. Inspired by software version control systems like git, we propose (a) a dataset version control system, giving users the ability to create, branch, merge, difference and search large, divergent collections of datasets, and (b) a platform, DataHub, that gives users the ability to perform collaborative data analysis building on this version control system. We outline the challenges in providing dataset version control at scale.\",\n \"Title: Knowing when you're wrong: building fast and reliable approximate query processing systems\\nYear: 2014\\n\\nAbstract: Modern data analytics applications typically process massive amounts of data on clusters of tens, hundreds, or thousands of machines to support near-real-time decisions.The quantity of data and limitations of disk and memory bandwidth often make it infeasible to deliver answers at interactive speeds. However, it has been widely observed that many applications can tolerate some degree of inaccuracy. This is especially true for exploratory queries on data, where users are satisfied with \\\\\\\"close-enough\\\\\\\" answers if they can come quickly. A popular technique for speeding up queries at the cost of accuracy is to execute each query on a sample of data, rather than the whole dataset. To ensure that the returned result is not too inaccurate, past work on approximate query processing has used statistical techniques to estimate \\\\\\\"error bars\\\\\\\" on returned results. However, existing work in the sampling-based approximate query processing (S-AQP) community has not validated whether these techniques actually generate accurate error bars for real query workloads. In fact, we find that error bar estimation often fails on real world production workloads. Fortunately, it is possible to quickly and accurately diagnose the failure of error estimation for a query. In this paper, we show that it is possible to implement a query approximation pipeline that produces approximate answers and reliable error bars at interactive speeds.\",\n \"Title: GenBase: a complex analytics genomics benchmark\\nYear: 2014\\n\\nAbstract: This paper introduces a new benchmark designed to test database management system (DBMS) performance on a mix of data management tasks (joins, filters, etc.) and complex analytics (regression, singular value decomposition, etc.) Such mixed workloads are prevalent in a number of application areas including most science workloads and web analytics. As a specific use case, we have chosen genomics data for our benchmark and have constructed a collection of typical tasks in this domain. In addition to being representative of a mixed data management and analytics workload, this benchmark is also meant to scale to large dataset sizes and multiple nodes across a cluster. Besides presenting this benchmark, we have run it on a variety of storage systems including traditional row stores, newer column stores, Hadoop, and an array DBMS. We present performance numbers on all systems on single and multiple nodes, and show that performance differs by orders of magnitude between the various solutions. In addition, we demonstrate that most platforms have scalability issues. We also test offloading the analytics onto a coprocessor. The intent of this benchmark is to focus research interest in this area; to this end, all of our data, data generators, and scripts are available on our web site.\",\n \"Title: Rethinking main memory OLTP recovery\\nYear: 2014\\n\\nAbstract: Fine-grained, record-oriented write-ahead logging, as exemplified by systems like ARIES, has been the gold standard for relational database recovery. In this paper, we show that in modern high-throughput transaction processing systems, this is no longer the optimal way to recover a database system. In particular, as transaction throughputs get higher, ARIES-style logging starts to represent a non-trivial fraction of the overall transaction execution time. We propose a lighter weight, coarse-grained command logging technique which only records the transactions that were executed on the database. It then does recovery by starting from a transactionally consistent checkpoint and replaying the commands in the log as if they were new transactions. By avoiding the overhead of fine-grained logging of before and after images (both CPU complexity as well as substantial associated 110), command logging can yield significantly higher throughput at run-time. Recovery times for command logging are higher compared to an ARIEs-style physiological logging approach, but with the advent of high-availability techniques that can mask the outage of a recovering node, recovery speeds have become secondary in importance to run-time performance for most applications. We evaluated our approach on an implementation of TPCC in a main memory database system (VoltDB), and found that command logging can offer 1.5 x higher throughput than a main-memory optimized implementation of ARIEs-style physiological logging.\",\n \"Title: GRAPHiQL: A graph intuitive query language for relational databases\\nYear: 2014\\n\\nAbstract: Graph analytics is becoming increasingly popular, driving many important business applications from social network analysis to machine learning. Since most graph data is collected in a relational database, it seems natural to attempt to perform graph analytics within the relational environment. However, SQL, the query language for relational databases, makes it difficult to express graph analytics operations. This is because SQL requires programmers to think in terms of tables and joins, rather than the more natural representation of graphs as collections of nodes and edges. As a result, even relatively simple graph operations can require very complex SQL queries. In this paper, we present GRAPHiQL, an intuitive query language for graph analytics, which allows developers to reason in terms of nodes and edges. GRAPHiQL provides key graph constructs such as looping, recursion, and neighborhood operations. At runtime, GRAPHiQL compiles graph programs into efficient SQL queries that can run on any relational database. We demonstrate the applicability of GRAPHiQL on several applications and compare the performance of GRAPHiQL queries with those of Apache Giraph (a popular `vertex centric' graph programming language).\",\n \"Title: TrajStore: An adaptive storage system for very large trajectory data sets\\nYear: 2010\\n\\nAbstract: The rise of GPS and broadband-speed wireless devices has led to tremendous excitement about a range of applications broadly characterized as \\\"location based services\\\". Current database storage systems, however, are inadequate for manipulating the very large and dynamic spatio-temporal data sets required to support such services. Proposals in the literature either present new indices without discussing how to cluster data, potentially resulting in many disk seeks for lookups of densely packed objects, or use static quadtrees or other partitioning structures, which become rapidly suboptimal as the data or queries evolve. As a result of these performance limitations, we built TrajStore, a dynamic storage system optimized for efficiently retrieving all data in a particular spatiotemporal region. TrajStore maintains an optimal index on the data and dynamically co-locates and compresses spatially and temporally adjacent segments on disk. By letting the storage layer evolve with the index, the system adapts to incoming queries and data and is able to answer most queries via a very limited number of I/Os, even when the queries target regions containing hundreds or thousands of different trajectories. I. INTRODUCTION\",\n \"Title: Database Abstractions for Managing Sensor Network Data\\nYear: 2010\\n\\nAbstract: Sensor networking hardware, networking, and operating system software has matured to the point that the major challenges facing the field now have to do with storing, cleaning, and querying the data such networks produce. In this paper, we survey several research systems designed for managing sensor data using declarative database-like abstractions from the database community and specifically the Massachusetts Institute of Technology (MIT, Cambridge) database group. The systems we discuss are designed to help prioritize data collection in the face of intermittent bandwidth, clean and smooth data using statistical models stored inside the database, and run declarative queries over probabilistic data.\",\n \"Title: SubZero: A fine-grained lineage system for scientific databases\\nYear: 2013\\n\\nAbstract: Data lineage is a key component of provenance that helps scientists track and query relationships between input and output data. While current systems readily support lineage relationships at the file or data array level, finer-grained support at an array-cell level is impractical due to the lack of support for user defined operators and the high runtime and storage overhead to store such lineage. We interviewed scientists in several domains to identify a set of common semantics that can be leveraged to efficiently store fine-grained lineage. We use the insights to define lineage representations that efficiently capture common locality properties in the lineage data, and a set of APIs so operator developers can easily export lineage information from user defined operators. Finally, we introduce two benchmarks derived from astronomy and genomics, and show that our techniques can reduce lineage query costs by up to 10× while incuring substantially less impact on workflow runtime and storage.\",\n \"Title: A Demonstration of the BigDAWG Polystore System.\\nYear: 2015\\n\\nAbstract: This paper presents BigDAWG, a reference implementation of a new architecture for \\\\\\\"Big Data\\\\\\\" applications. Such applications not only call for large-scale analytics, but also for real-time streaming support, smaller analytics at interactive speeds, data visualization, and cross-storage-system queries. Guided by the principle that \\\\\\\"one size does not fit all\\\\\\\", we build on top of a variety of storage engines, each designed for a specialized use case. To illustrate the promise of this approach, we demonstrate its effectiveness on a hospital application using data from an intensive care unit (ICU). This complex application serves the needs of doctors and researchers and provides real-time support for streams of patient data. It showcases novel approaches for querying across multiple storage engines, data visualization, and scalable real-time analytics.\",\n \"Title: S-Store: Streaming Meets Transaction Processing.\\nYear: 2015\\n\\nAbstract: Stream processing addresses the needs of real-time applications. Transaction processing addresses the coordination and safety of short atomic computations. Heretofore, these two modes of operation existed in separate, stove-piped systems. In this work, we attempt to fuse the two computational paradigms in a single system called S-Store. In this way, S-Store can simultaneously accommodate OLTP and streaming applications. We present a simple transaction model for streams that integrates seamlessly with a traditional OLTP system, and provides both ACID and stream-oriented guarantees. We chose to build S-Store as an extension of H-Store - an open-source, in-memory, distributed OLTP database system. By implementing S-Store in this way, we can make use of the transaction processing facilities that H-Store already provides, and we can concentrate on the additional features that are needed to support streaming. Similar implementations could be done using other main-memory OLTP platforms. We show that we can actually achieve higher throughput for streaming workloads in S-Store than an equivalent deployment in H-Store alone. We also show how this can be achieved within H-Store with the addition of a modest amount of new functionality. Furthermore, we compare S-Store to two state-of-the-art streaming systems, Esper and Apache Storm, and show how S-Store can sometimes exceed their performance while at the same time providing stronger correctness guarantees.\",\n \"Title: SeeDB: Efficient Data-Driven Visualization Recommendations to Support Visual Analytics.\\nYear: 2015\\n\\nAbstract: Data analysts often build visualizations as the first step in their analytical workflow. However, when working with high-dimensional datasets, identifying visualizations that show relevant or desired trends in data can be laborious. We propose SeeDB, a visualization recommendation engine to facilitate fast visual analysis: given a subset of data to be studied, SeeDB intelligently explores the space of visualizations, evaluates promising visualizations for trends, and recommends those it deems most \\\"useful\\\" or \\\"interesting\\\". The two major obstacles in recommending interesting visualizations are (a) scale: evaluating a large number of candidate visualizations while responding within interactive time scales, and (b) utility: identifying an appropriate metric for assessing interestingness of visualizations. For the former, SeeDB introduces pruning optimizations to quickly identify high-utility visualizations and sharing optimizations to maximize sharing of computation across visualizations. For the latter, as a first step, we adopt a deviation-based metric for visualization utility, while indicating how we may be able to generalize it to other factors influencing utility. We implement SeeDB as a middleware layer that can run on top of any DBMS. Our experiments show that our framework can identify interesting visualizations with high accuracy. Our optimizations lead to multiple orders of magnitude speedup on relational row and column stores and provide recommendations at interactive time scales. Finally, we demonstrate via a user study the effectiveness of our deviation-based utility metric and the value of recommendations in supporting visual analytics.\",\n \"Title: The BigDAWG Architecture.\\nYear: 2016\\n\\nAbstract: BigDAWG is a polystore system designed to work on complex problems that naturally span across different processing or storage engines. BigDAWG provides an architecture that supports diverse database systems working with different data models, support for the competing notions of location transparency and semantic completeness via islands of information and a middleware that provides a uniform multi-island interface. In this article, we describe the current architecture of BigDAWG, its application on the MIMIC II medical dataset, and our plans for the mechanics of cross-system queries. During the presentation, we will also deliver a brief demonstration of the current version of BigDAWG.\",\n \"Title: MacroBase: Analytic Monitoring for the Internet of Things.\\nYear: 2016\\n\\nAbstract: An increasing proportion of data today is generated by automated processes, sensors, and systems---collectively, the Internet of Things (IoT). A key challenge in IoT data management and a core aspect of many IoT applications (e.g., industrial diagnostics, predictive maintenance, and equipment auditing) is in identifying and highlighting unusual and surprising data (e.g., poor driving behavior, equipment failures, physical intrusion). We call this task, which is often statistical in nature and time-sensitive, analytic monitoring. To facilitate rapid development and scalable deployment of analytic monitoring queries, we have developed MacroBase, a data analytics engine that performs analytic monitoring of IoT data streams. MacroBase implements a customizable pipeline of outlier detection, summarization, and ranking operators. For efficient and accurate execution, MacroBase implements several cross-layer optimizations across robust estimation, pattern mining, and sketching procedures, allowing order-of-magnitude speedups. As a result, MacroBase can analyze up to 1M events per second on a single core. MacroBase has already delivered meaningful analytic monitoring results in production at a medium-scale IoT startup.\",\n \"Title: Refinement Driven Processing of Aggregation Constrained Queries.\\nYear: 2016\\n\\nAbstract: Although existing database systems provide users an efficient means to select tuples based on attribute criteria, they however provide little means to select tuples based on whether they meet aggregate requirements. For instance, a requirement may be that the cardinality of the query result must be 1000 or the sum of a particular attribute must be u003c $5000. In this work, we term such queries as “Aggregation Constrained Queries” (ACQs). Aggregation constrained queries are crucial in many decision support applications to maintain a product’s competitive edge in this fast moving field of data processing. The challenge in processing ACQs is the unfamiliarity of the underlying data that results in queries being either too strict or too broad. Due to the lack of support of ACQs, users have to resort to a frustrating trial-and-error query refinement process. In this paper, we introduce and define the semantics of ACQs. We propose a refinement-based approach, called ACQUIRE, to efficiently process a range of ACQs. Lastly, in our experimental analysis we demonstrate the superiority of our technique over extensions of existing algorithms. More specifically, ACQUIRE runs up to 2 orders of magnitude faster than compared techniques while producing a 2X reduction in the amount of refinement made to the input queries.\",\n \"Title: Graph analytics using vertica relational database\\nYear: 2015\\n\\nAbstract: Graph analytics is becoming increasingly popular, with a number of new applications and systems developed in the past few years. In this paper, we study Vertica relational database as a platform for graph analytics. We show that vertex-centric graph analysis can be translated to SQL queries, typically involving table scans and joins, and that modern column-oriented databases are very well suited to running such queries. Furthermore, we show how developers can trade memory footprint for significantly reduced I/O costs in Vertica. We present an experimental evaluation of the Vertica relational database system on a variety of graph analytics, including iterative analysis, a combination of graph and relational analyses, and more complex 1-hop neighborhood graph analytics, showing that it is competitive to two popular vertex-centric graph analytics systems, namely Giraph and GraphLab.\",\n \"Title: Interactive data analytics: the new frontier\\nYear: 2015\\n\\nAbstract: Data analytics often involves data exploration, where a data set is repeatedly analyzed to understand root causes, find patterns, or extract insights. Such analysis is frequently bottlenecked by the underlying data processing system, as analysts wait for their queries to complete against a complex multilayered software stack. In this talk, I'll describe some exploratory analytics applications we've build in the MIT database group over the past few years, and will then describe some of the challenges and opportunities that arise when building more efficient data exploration systems that will allow these applications to become truly interactive, even when processing billions of data points.\",\n \"Title: BigDansing: A System for Big Data Cleansing\\nYear: 2015\\n\\nAbstract: Data cleansing approaches have usually focused on detecting and fixing errors with little attention to scaling to big datasets. This presents a serious impediment since data cleansing often involves costly computations such as enumerating pairs of tuples, handling inequality joins, and dealing with user-defined functions. In this paper, we present BigDansing, a Big Data Cleansing system to tackle efficiency, scalability, and ease-of-use issues in data cleansing. The system can run on top of most common general purpose data processing platforms, ranging from DBMSs to MapReduce-like frameworks. A user-friendly programming interface allows users to express data quality rules both declaratively and procedurally, with no requirement of being aware of the underlying distributed platform. BigDansing takes these rules into a series of transformations that enable distributed computations and several optimizations, such as shared scans and specialized joins operators. Experimental results on both synthetic and real datasets show that BigDansing outperforms existing baseline systems up to more than two orders of magnitude without sacrificing the quality provided by the repair algorithms.\",\n \"Title: Decibel: The Relational Dataset Branching System.\\nYear: 2016\\n\\nAbstract: As scientific endeavors and data analysis become increasingly collaborative, there is a need for data management systems that natively support the versioning or branching of datasets to enable concurrent analysis, cleaning, integration, manipulation, or curation of data across teams of individuals. Common practice for sharing and collaborating on datasets involves creating or storing multiple copies of the dataset, one for each stage of analysis, with no provenance information tracking the relationships between these datasets. This results not only in wasted storage, but also makes it challenging to track and integrate modifications made by different users to the same dataset. In this paper, we introduce the Relational Dataset Branching System, Decibel, a new relational storage system with built-in version control designed to address these short-comings. We present our initial design for Decibel and provide a thorough evaluation of three versioned storage engine designs that focus on efficient query processing with minimal storage overhead. We also develop an exhaustive benchmark to enable the rigorous testing of these and future versioned storage engine designs.\",\n \"Title: ModelDB: a system for machine learning model management.\\nYear: 2017\\n\\nAbstract: Building a machine learning model is an iterative process. A data scientist will build many tens to hundreds of models before arriving at one that meets some acceptance criteria (e.g. AUC cutoff, accuracy threshold). However, the current style of model building is ad-hoc and there is no practical way for a data scientist to manage models that are built over time. As a result, the data scientist must attempt to \\\\\\\"remember\\\\\\\" previously constructed models and insights obtained from them. This task is challenging for more than a handful of models and can hamper the process of sensemaking. Without a means to manage models, there is no easy way for a data scientist to answer questions such as \\\\\\\"Which models were built using an incorrect feature?\\\\\\\", \\\\\\\"Which model performed best on American customers?\\\\\\\" or \\\\\\\"How did the two top models compare?\\\\\\\" In this paper, we describe our ongoing work on ModelDB, a novel end-to-end system for the management of machine learning models. ModelDB clients automatically track machine learning models in their native environments (e.g. scikit-learn, spark.ml), the ModelDB backend introduces a common layer of abstractions to represent models and pipelines, and the ModelDB frontend allows visual exploration and analyses of models via a web-based interface.\",\n \"Title: Towards large-scale data discovery: position paper.\\nYear: 2016\\n\\nAbstract: With thousands of data sources spread across multiple databases and data lakes, modern organizations face a data discovery challenge. Analysts spend more time finding relevant data to answer the questions at hand than analyzing it. In this paper we introduce a data discovery system that facilitates locating relevant data among thousands of data sources. We represent data sources succinctly through signatures, and then create search paths that permit quick execution of a set of data discovery primitives used for finding relevant data. We have built a prototype that is being used to solve data discovery challenges of two big organizations.\",\n \"Title: Amoeba: A Shape changing Storage System for Big Data.\\nYear: 2016\\n\\nAbstract: Data partitioning significantly improves the query performance in distributed database systems. A large number of techniques have been proposed to efficiently partition a dataset for a given query workload. However, many modern analytic applications involve ad-hoc or exploratory analysis where users do not have a representative query workload upfront. Furthermore, workloads change over time as businesses evolve or as analysts gain better understanding of their data. Static workload-based data partitioning techniques are therefore not suitable for such settings. In this paper, we describe the demonstration of Amoeba, a distributed storage system which uses adaptive multi-attribute data partitioning to efficiently support ad-hoc as well as recurring queries. Amoeba applies a robust partitioning algorithm such that ad-hoc queries on all attributes have similar performance gains. Thereafter, Amoeba adaptively repartitions the data based on the observed query sequence, i.e., the system improves over time. All along Amoeba offers both adaptivity (i.e., adjustments according to workload changes) as well as robustness (i.e., avoiding performance spikes due to workload changes). We propose to demonstrate Amoeba on scenarios from an internet-of-things startup that tracks user driving patterns. We invite the audience to interactively fire fast ad-hoc queries, observe multi-dimensional adaptivity, and play with a robust/reactive knob in Amoeba. The web front end displays the layout changes, runtime costs, and compares it to Spark with both default and workload-aware partitioning.\",\n \"Title: The BigDAWG polystore system and architecture\\nYear: 2016\\n\\nAbstract: Organizations are often faced with the challenge of providing data management solutions for large, heterogenous datasets that may have different underlying data and programming models. For example, a medical dataset may have unstructured text, relational data, time series waveforms and imagery. Trying to fit such datasets in a single data management system can have adverse performance and efficiency effects. As a part of the Intel Science and Technology Center on Big Data, we are developing a polystore system designed for such problems. BigDAWG (short for the Big Data Analytics Working Group) is a polystore system designed to work on complex problems that naturally span across different processing or storage engines. BigDAWG provides an architecture that supports diverse database systems working with different data models, support for the competing notions of location transparency and semantic completeness via islands and a middleware that provides a uniform multi-island interface. Initial results from a prototype of the BigDAWG system applied to a medical dataset validate polystore concepts. In this article, we will describe polystore databases, the current BigDAWG architecture and its application on the MIMIC II medical dataset, initial performance results and our future development plans.\",\n \"Title: The TileDB Array Data Storage Manager.\\nYear: 2016\\n\\nAbstract: We present a novel storage manager for multi-dimensional arrays that arise in scientific applications, which is part of a larger scientific data management system called TileDB. In contrast to existing solutions, TileDB is optimized for both dense and sparse arrays. Its key idea is to organize array elements into ordered collections called fragments. Each fragment is dense or sparse, and groups contiguous array elements into data tiles of fixed capacity. The organization into fragments turns random writes into sequential writes, and, coupled with a novel read algorithm, leads to very efficient reads. TileDB enables parallelization via multi-threading and multi-processing, offering thread-/process-safety and atomicity via lightweight locking. We show that TileDB delivers comparable performance to the HDF5 dense array storage manager, while providing much faster random writes. We also show that TileDB offers substantially faster reads and writes than the SciDB array database system with both dense and sparse arrays. Finally, we demonstrate that TileDB is considerably faster than adaptations of the Vertica relational column-store for dense array storage management, and at least as fast for the case of sparse arrays.\",\n \"Title: AdaptDB: Adaptive Partitioning for Distributed Joins.\\nYear: 2017\\n\\nAbstract: Big data analytics often involves complex join queries over two or more tables. Such join processing is expensive in a distributed setting both because large amounts of data must be read from disk, and because of data shuffling across the network. Many techniques based on data partitioning have been proposed to reduce the amount of data that must be accessed, often focusing on finding the best partitioning scheme for a particular workload, rather than adapting to changes in the workload over time. In this paper, we present AdaptDB, an adaptive storage manager for analytical database workloads in a distributed setting. It works by partitioning datasets across a cluster and incrementally refining data partitioning as queries are run. AdaptDB introduces a novel hyper-join that avoids expensive data shuffling by identifying storage blocks of the joining tables that overlap on the join attribute, and only joining those blocks. Hyper-join performs well when each block in one table overlaps with few blocks in the other table, since that will minimize the number of blocks that have to be accessed. To minimize the number of overlapping blocks for common join queries, AdaptDB users smooth repartitioning to repartition small portions of the tables on join attributes as queries run. A prototype of AdaptDB running on top of Spark improves query performance by 2--3x on TPC-H as well as real-world dataset, versus a system that employs scans and shuffle-joins.\",\n \"Title: Speedy Browsing and Sampling with NeedleTail.\\nYear: 2016\\n\\nAbstract: Exploratory data analysis often involves repeatedly browsing small samples of records that satisfy certain ad-hoc predicates, to form and test hypotheses, identify correlations, or make inferences. Unfortunately, existing database systems are not optimized for queries with a LIMIT clause---operating instead in an all-or-nothing manner. While workload aware caching, indexing, or precomputation schemes may appear promising remedies, they do not apply in an exploratory setting where the queries are ad-hoc and unpredictable. In this paper, we propose a fast sampling engine, called NeedleTail, aimed at letting analysts browse a small sample of the query results on large datasets as quickly as possible, independent of the overall size of the result set. NeedleTail introduces density maps, a lightweight in-memory indexing structure, and a set of efficient algorithms (with desirable theoretical guarantees) to quickly locate promising blocks, trading off locality and density. In settings where the samples are used to compute aggregates, we extend techniques from the statistics literature---in particular, from survey sampling---to mitigate the bias from using our sampling algorithms. Our experimental results demonstrate that NeedleTail returns results an order of magnitude faster while occupying up to 30x less memory than existing sampling techniques.\",\n \"Title: INGESTBASE: A Declarative Data Ingestion System.\\nYear: 2017\\n\\nAbstract: Big data applications have fast arriving data that must be quickly ingested. At the same time, they have specific needs to preprocess and transform the data before it could be put to use. The current practice is to do these preparatory transformations once the data is already ingested, however, this is expensive to run and cumbersome to manage. As a result, there is a need to push data preprocessing down to the ingestion itself. In this paper, we present a declarative data ingestion system, called INGESTBASE, to allow application developers to plan and specify their data ingestion logic in a more systematic manner. We introduce the notion of ingestions plans, analogous to query plans, and present a declarative ingestion language to help developers easily build sophisticated ingestion plans. INGESTBASE provides an extensible ingestion optimizer to rewrite and optimize ingestion plans by applying rules such as operator reordering and pipelining. Finally, the INGESTBASE runtime engine runs the optimized ingestion plan in a distributed and fault-tolerant manner. Later, at query processing time, INGESTBASE supports ingestion-aware data access and interfaces with upstream query processors, such as Hadoop MapReduce and Spark, to post- process the ingested data. We demonstrate through a number of experiments that INGESTBASE: (i) is flexible enough to express a variety of ingestion techniques, (ii) incurs a low ingestion overhead, (iii) provides efficient access to the ingested data, and (iv) has much better performance, up to 6 times, than preparing data as an afterthought, via a query processor.\",\n \"Title: Towards Visualization Recommendation Systems.\\nYear: 2016\\n\\nAbstract: Data visualization is often used as the first step while performing a variety of analytical tasks. With the advent of large, high-dimensional datasets and significant interest in data science, there is a need for tools that can support rapid visual analysis. In this paper we describe our vision for a new class of visualization systems, namely visualization recommendation systems, that can automatically identify and interactively recommend visualizations relevant to an analytical task. We detail the key requirements and design considerations for a visualization recommendation system. We also identify a number of challenges in realizing this vision and describe some approaches to address them.\",\n \"Title: A Demo of the Data Civilizer System.\\nYear: 2017\\n\\nAbstract: Finding relevant data for a specific task from the numerous data sources available in any organization is a daunting task. This is not only because of the number of possible data sources where the data of interest resides, but also due to the data being scattered all over the enterprise and being typically dirty and inconsistent. In practice, data scientists are routinely reporting that the majority (more than 80%) of their effort is spent finding, cleaning, integrating, and accessing data of interest to a task at hand. We propose to demonstrate DATA CIVILIZER to ease the pain faced in analyzing data \\\\\\\"in the wild\\\\\\\". DATA CIVILIZER is an end-to-end big data management system with components for data discovery, data integration and stitching, data cleaning, and querying data from a large variety of storage engines, running in large enterprises.\",\n \"Title: Generating Concise Entity Matching Rules.\\nYear: 2017\\n\\nAbstract: Entity matching (EM) is a critical part of data integration and cleaning. In many applications, the users need to understand why two entities are considered a match, which reveals the need for interpretable and concise EM rules. We model EM rules in the form of General Boolean Formulas (GBFs) that allows arbitrary attribute matching combined by conjunctions (∨), disjunctions (∧), and negations. (¬) GBFs can generate more concise rules than traditional EM rules represented in disjunctive normal forms (DNFs). We use program synthesis, a powerful tool to automatically generate rules (or programs) that provably satisfy a high-level specification, to automatically synthesize EM rules in GBF format, given only positive and negative matching examples. In this demo, attendees will experience the following features: (1) Interpretability -- they can see and measure the conciseness of EM rules defined using GBFs; (2) Easy customization -- they can provide custom experiment parameters for various datasets, and, easily modify a rich predefined (default) synthesis grammar, using a Web interface; and (3) High performance -- they will be able to compare the generated concise rules, in terms of accuracy, with probabilistic models (e.g., machine learning methods), and hand-written EM rules provided by experts. Moreover, this system will serve as a general platform for evaluating different methods that discover EM rules, which will be released as an open-source tool on GitHub.\",\n \"Title: Exploring big volume sensor data with vroom\\nYear: 2017\\n\\nAbstract: AbstractState of the art sensors within a single autonomous vehicle (AV) can produce video and LIDAR data at rates greater than 30 GB/hour. Unsurprisingly, even small AV research teams can accumulate tens of terabytes of sensor data from multiple trips and multiple vehicles. AV practitioners would like to extract information about specific locations or specific situations for further study, but are often unable to. Queries over AV sensor data are different from generic analytics or spatial queries because they demand reasoning about fields of view as well as heavy computation to extract features from scenes. In this article and demo we present Vroom, a system for ad-hoc queries over AV sensor databases. Vroom combines domain specific properties of AV datasets with selective indexing and multi-query optimization to address challenges posed by AV sensor data.\",\n \"Title: Query optimization for dynamic imputation\\nYear: 2017\\n\\nAbstract: AbstractMissing values are common in data analysis and present a usability challenge. Users are forced to pick between removing tuples with missing values or creating a cleaned version of their data by applying a relatively expensive imputation strategy. Our system, ImputeDB, incorporates imputation into a cost-based query optimizer, performing necessary imputations on-the-fly for each query. This allows users to immediately explore their data, while the system picks the optimal placement of imputation operations. We evaluate this approach on three real-world survey-based datasets. Our experiments show that our query plans execute between 10 and 140 times faster than first imputing the base tables. Furthermore, we show that the query results from on-the-fly imputation differ from the traditional base-table imputation approach by 0--8%. Finally, we show that while dropping tuples with missing values that fail query constraints discards 6--78% of the data, on-the-fly imputation loses only 0--21%.\",\n \"Title: A robust partitioning scheme for ad-hoc query workloads.\\nYear: 2017\\n\\nAbstract: Data partitioning is crucial to improving query performance several workload-based partitioning techniques have been proposed in database literature. However, many modern analytic applications involve ad-hoc or exploratory analysis where users do not have a representative query workload a priori. Static workload-based data partitioning techniques are therefore not suitable for such settings. In this paper, we propose Amoeba, a distributed storage system that uses adaptive multi-attribute data partitioning to efficiently support ad-hoc as well as recurring queries. Amoeba requires zero set-up and tuning effort, allowing analysts to get the benefits of partitioning without requiring an upfront query workload. The key idea is to build and maintain a partitioning tree on top of the dataset. The partitioning tree allows us to answer queries with predicates by reading a subset of the data. The initial partitioning tree is created without requiring an upfront query workload and Amoeba adapts it over time by incrementally modifying subtrees based on user queries using repartitioning. A prototype of Amoeba running on top of Apache Spark improves query performance by up to 7x over full scans and up to 2x over range-based partitioning techniques on TPC-H as well as a real-world workload.\",\n \"Title: Bigdawg Version 0.1\\nYear: 2017\\n\\nAbstract: A polystore system is a database management system composed of integrated heterogeneous database engines and multiple programming languages. By matching data to the storage engine best suited to its needs, complex analytics run faster and flexible storage choices helps improve data organization. BigDAWG (Big Data Working Group) is our prototype implementation of a polystore system. In this paper, we describe the current BigDAWG software release which supports PostgreSQL, Accumulo and SciDB. We describe the overall architecture, API and initial results of applying BigDAWG to the MIMIC II medical dataset.\",\n \"Title: Weld: Rethinking the Interface Between Data-Intensive Applications.\\nYear: 2017\\n\\nAbstract: Data analytics applications combine multiple functions from different libraries and frameworks. Even when each function is optimized in isolation, the performance of the combined application can be an order of magnitude below hardware limits due to extensive data movement across these functions. To address this problem, we propose Weld, a new interface between data-intensive libraries that can optimize across disjoint libraries and functions. Weld exposes a lazily-evaluated API where diverse functions can submit their computations in a simple but general intermediate representation that captures their data-parallel structure. It then optimizes data movement across these functions and emits efficient code for diverse hardware. Weld can be integrated into existing frameworks such as Spark, TensorFlow, Pandas and NumPy without changing their user-facing APIs. We demonstrate that Weld can speed up applications using these frameworks by up to 29x.\",\n \"Title: Entity Consolidation: The Golden Record Problem.\\nYear: 2017\\n\\nAbstract: Four key processes in data integration are: data preparation (i.e., extracting, transforming, and cleaning data), schema integration (i.e., identifying attribute correspondences), entity resolution (i.e., finding clusters of records that represent the same entity) and entity consolidation (i.e., merging each cluster into a u0027golden recordu0027, which contains the canonical value for each attribute). In real-world scenarios, Master Data Management (MDM) is often employed to perform the last two steps using a u0027match-mergeu0027 module, which is driven by a collection of user-written match and merge rules. However, it is well understood that such solutions often fail to scale to the sizes and complexity of problems currently being addressed. Scalable solutions to entity resolution have been previously developed to generate a collection of clusters of records representing the same entity. In this paper, we propose a scalable entity consolidation algorithm to merge these clusters into u0027golden recordsu0027. We first automatically generate matching rules from the clusters and then group these rules into sets with common characteristics to cut down on the number which must be verified by a human. Next, for the human-approved rule groups, we apply them to merge the duplicate attribute values in the clusters. Finally, we employ existing truth discovery methods, such as majority consensus (MC), to resolve remaining conflicts in the clusters. We applied our methods on three real-world datasets. In a dataset with 31,023 clusters and 80,451 duplicate records, 72,239 matching rules were generated. By having a human con rm only 100 algorithm-generated rule groups, we achieved a recall of 75% and a precision of 98% for merging duplicate attribute values. When we invoked our algorithm prior to running MC, we improved the precision of golden record construction by 40%.\",\n \"Title: Efficient Top-K Query Processing on Massively Parallel Hardware.\\nYear: 2018\\n\\nAbstract: A common operation in many data analytics workloads is to find the top-k items, i.e., the largest or smallest operations according to some sort order (implemented via LIMIT or ORDER BY expressions in SQL). A naive implementation of top-k is to sort all of the items and then return the first k, but this does much more work than needed. Although efficient implementations for top-k have been explored on traditional multi-core processors, there has been no prior systematic study of top-k implementations on GPUs, despite open requests for such implementations in GPU-based frameworks like TensorFlow and ArrayFire. In this work, we present several top-k algorithms for GPUs, including a new algorithm based on bitonic sort called bitonic top-k. The bitonic top-k algorithm is up to a factor of \\\\new15x faster than sort and 4x faster than a variety of other possible implementations for values of k up to 256. We also develop a cost model to predict the performance of several of our algorithms, and show that it accurately predicts actual performance on modern GPUs.\",\n \"Title: MISTIQUE: A System to Store and Query Model Intermediates for Model Diagnosis.\\nYear: 2018\\n\\nAbstract: Model diagnosis is the process of analyzing machine learning (ML) model performance to identify where the model works well and where it doesn't. It is a key part of the modeling process and helps ML developers iteratively improve model accuracy. Often, model diagnosis is performed by analyzing different datasets or intermediates associated with the model such as the input data and hidden representations learned by the model (e.g., [4, 24, 39,]). The bottleneck in fast model diagnosis is the creation and storage of model intermediates. Storing these intermediates requires tens to hundreds of GB of storage whereas re-running the model for each diagnostic query slows down model diagnosis. To address this bottleneck, we propose a system called MISTIQUE that can work with traditional ML pipelines as well as deep neural networks to efficiently capture, store, and query model intermediates for diagnosis. For each diagnostic query, MISTIQUE intelligently chooses whether to re-run the model or read a previously stored intermediate. For intermediates that are stored in MISTIQUE, we propose a range of optimizations to reduce storage footprint including quantization, summarization, and data de-duplication. We evaluate our techniques on a range of real-world ML models in scikit-learn and Tensorflow. We demonstrate that our optimizations reduce storage by up to 110X for traditional ML pipelines and up to 6X for deep neural networks. Furthermore, by using MISTIQUE, we can speed up diagnostic queries on traditional ML pipelines by up to 390X and 210X on deep neural networks.\",\n \"Title: Evaluating end-to-end optimization for data analytics applications in weld\\nYear: 2018\\n\\nAbstract: AbstractModern analytics applications use a diverse mix of libraries and functions. Unfortunately, there is no optimization across these libraries, resulting in performance penalties as high as an order of magnitude in many applications. To address this problem, we proposed Weld, a common runtime for existing data analytics libraries that performs key physical optimizations such as pipelining under existing, imperative library APIs. In this work, we further develop the Weld vision by designing an automatic adaptive optimizer for Weld applications, and evaluating its impact on realistic data science workloads. Our optimizer eliminates multiple forms of overhead that arise when composing imperative libraries like Pandas and NumPy, and uses lightweight measurements to make data-dependent decisions at run-time in ad-hoc workloads where no statistics are available, with sub-second overhead. We also evaluate which optimizations have the largest impact in practice and whether Weld can be integrated into libraries incrementally. Our results are promising: using our optimizer, Weld accelerates data science workloads by up to 23X on one thread and 80X on eight threads, and its adaptive optimizations provide up to a 3.75X speedup over rule-based optimization. Moreover, Weld provides benefits if even just 4--5 operators in a library are ported to use it. Our results show that common runtime designs like Weld may be a viable approach to accelerate analytics.\",\n \"Title: Smallify: Learning Network Size while Training.\\nYear: 2018\\n\\nAbstract: As neural networks become widely deployed in different applications and on different hardware, it has become increasingly important to optimize inference time and model size along with model accuracy. Most current techniques optimize model size, model accuracy and inference time in different stages, resulting in suboptimal results and computational inefficiency. In this work, we propose a new technique called Smallify that optimizes all three of these metrics at the same time. Specifically we present a new method to simultaneously optimize network size and model performance by neuron-level pruning during training. Neuron-level pruning not only produces much smaller networks but also produces dense weight matrices that are amenable to efficient inference. By applying our technique to convolutional as well as fully connected models, we show that Smallify can reduce network size by 35X with a 6X improvement in inference time with similar accuracy as models found by traditional training techniques.\",\n \"Title: Aurum: A Data Discovery System\\nYear: 2018\\n\\nAbstract: Organizations face a data discovery problem when their analysts spend more time looking for relevant data than analyzing it. This problem has become commonplace in modern organizations as: i) data is stored across multiple storage systems, from databases to data lakes, to the cloud; ii) data scientists do not operate within the limits of well-defined schemas or a small number of data sources—instead, to answer complex questions they must access data spread across thousands of data sources. To address this problem, we capture relationships between datasets in an enterprise knowledge graph (EKG), which helps users to navigate among disparate sources. The contribution of this paper is AURUM, a system to build, maintain and query the EKG. To build the EKG, we introduce a Two-step process which scales to large datasets and requires only one-pass over the data, avoiding overloading the source systems. To maintain the EKG without re-reading all data every time, we introduce a resource-efficient sampling signature (RESS) method which works by only using a small sample of the data. Finally, to query the EKG, we introduce a collection of composable primitives, thus allowing users to define many different types of discovery queries. We describe our experience using AURUM in three corporate scenarios and do a performance evaluation of each component.\",\n \"Title: Seeping Semantics: Linking Datasets Using Word Embeddings for Data Discovery\\nYear: 2018\\n\\nAbstract: Employees that spend more time finding relevant data than analyzing it suffer from a data discovery problem. The large volume of data in enterprises, and sometimes the lack of knowledge of the schemas aggravates this problem. Similar to how we navigate the Web, we propose to identify semantic links that assist analysts in their discovery tasks. These links relate tables to each other, to facilitate navigating the schemas. They also relate data to external data sources, such as ontologies and dictionaries, to help explain the schema meaning. We materialize the links in an enterprise knowledge graph, where they become available to analysts. The main challenge is how to find pairs of objects that are semantically related. We propose SEMPROP, a DAG of different components that find links based on syntactic and semantic similarities. SEMPROP is commanded by a semantic matcher which leverages word embeddings to find objects that are semantically related. We introduce coherent group, a technique to combine word embeddings that works better than other state of the art combination alternatives. We implement SEMPROP as part of Aurum, a data discovery system we are building, and conduct user studies, real deployments and a quantitative evaluation to understand the benefits of links for data discovery tasks, as well as the benefits of SEMPROP and coherent groups to find those links.\",\n \"Title: STAR: Scaling Transactions through Asymmetrical Replication.\\nYear: 2018\\n\\nAbstract: In this paper, we present STAR, a new distributed and replicated in-memory database. By employing a single-node non-partitioned architecture for some replicas and a partitioned architecture for other replicas, STAR is able to efficiently run both highly partitionable workloads and workloads that involve cross-partition transactions. The key idea is a new phase-switching algorithm where the execution of single-partition and cross-partition transactions are separated. In the partitioned phase, single-partition transactions are run on multiple machines in parallel to exploit more concurrency. In the single-master phase, mastership for the entire database is switched to a designated coordinator node, which can execute these transactions without the use of expensive coordination protocols like two-phase commit. Because the coordinator node has a full copy of the database, this phase-switching can be done at negligible cost. Our experiments on two popular benchmarks (YCSB and TPC-C) show that high availability via replication can coexist with fast serializable transaction execution in distributed in-memory databases, with STAR outperforming systems that employ conventional concurrency control and replication algorithms by up to one order of magnitude.\",\n \"Title: MacroBase: Prioritizing Attention in Fast Data.\\nYear: 2018\\n\\nAbstract: As data volumes continue to rise, manual inspection is becoming increasingly untenable. In response, we present MacroBase, a data analytics engine that prioritizes end-user attention in high-volume fast data streams. MacroBase enables efficient, accurate, and modular analyses that highlight and aggregate important and unusual behavior, acting as a search engine for fast data. MacroBase is able to deliver order-of-magnitude speedups over alternatives by optimizing the combination of explanation (i.e., feature selection) and classification tasks and by leveraging a new reservoir sampler and heavy-hitters sketch specialized for fast data streams. As a result, MacroBase delivers accurate results at speeds of up to 2M events per second per query on a single core. The system has delivered meaningful results in production, including at a telematics company monitoring hundreds of thousands of vehicles.\",\n \"Title: SWIFT: Mining Representative Patterns from Large Event Streams.\\nYear: 2018\\n\\nAbstract: Event streams generated by smart devices common in modern Internet of Things applications must be continuously mined to monitor the behavior of the underlying system. In this work, we propose a stream pattern mining system for supporting online IoT applications. First, to solve the pattern explosion problem of existing stream pattern mining strategies, we now design pattern semantics that continuously produce a compact set of patterns that max-imumly compresses the dynamic data streams, called MDL-based Representative Patterns (MRP). We then design a one-pass SWIFT approach that continuously mines the up-to-date MRP pattern set for each stream window upon the arrival or expiration of individual events. We show that SWIFT is guaranteed to select the update operation for each individual incoming event that leads to the most compact encoding of the sequence in the current window. We further enhance SWIFT to support batch updates, called B-SWIFT. B-SWIFT adopts a lazy update strategy that guarantees that only the minimal number of operations are conducted to process an incoming event batch for MRP pattern mining. Evaluation by our industry lighting lab collaborator demonstrates that SWIFT successfully solves their use cases and finds more representative patterns than the alternative approaches adapting the state-of-the-art static representative pattern mining methods. Our experimental study confirms that SWIFT outperforms the best existing method up to 50% in the compactness of produced pattern encodings, while providing a 4 orders of magnitude speedup.\",\n \"Title: Transactional consistency and automatic management in an application data cache\\nYear: 2010\\n\\nAbstract: Distributed in-memory application data caches like memcached are a popular solution for scaling database-driven web sites. These systems are easy to add to existing deployments, and increase performance significantly by reducing load on both the database and application servers. Unfortunately, such caches do not integrate well with the database or the application. They cannot maintain transactional consistency across the entire system, violating the isolation properties of the underlying database. They leave the application responsible for locating data in the cache and keeping it up to date, a frequent source of application complexity and programming errors. Addressing both of these problems, we introduce a transactional cache, TxCache, with a simple programming model. TxCache ensures that any data seen within a transaction, whether it comes from the cache or the database, reflects a slightly stale but consistent snapshot of the database. TxCache makes it easy to add caching to an application by simply designating functions as cacheable; it automatically caches their results, and invalidates the cached data as the underlying database changes. Our experiments found that adding TxCache increased the throughput of a web application by up to 5.2×, only slightly less than a non-transactional cache, showing that consistency does not have to come at the price of performance.\",\n \"Title: BigDAWG Polystore Release and Demonstration.\\nYear: 2017\\n\\nAbstract: The Intel Science and Technology Center for Big Data is developing a reference implementation of a Polystore database. The BigDAWG (Big Data Working Group) system supports many sizes of database engines, multiple programming languages and complex analytics for a variety of workloads. Our recent efforts include application of BigDAWG to an ocean metagenomics problem and containerization of BigDAWG. We intend to release an open source BigDAWG v1.0 in the Spring of 2017. In this article, we will demonstrate a number of polystore applications developed with oceanographic researchers at MIT and describe our forthcoming open source release of the BigDAWG system.\",\n \"Title: BigDAWG version 0.1\\nYear: 2017\\n\\nAbstract: A polystore system is a database management system composed of integrated heterogeneous database engines and multiple programming languages. By matching data to the storage engine best suited to its needs, complex analytics run faster and flexible storage choices helps improve data organization. BigDAWG (Big Data Working Group) is our prototype implementation of a polystore system. In this paper, we describe the current BigDAWG software release which supports PostgreSQL, Accumulo and SciDB. We describe the overall architecture, API and initial results of applying BigDAWG to the MIMIC II medical dataset.\",\n \"Title: Unsupervised String Transformation Learning for Entity Consolidation\\nYear: 2019\\n\\nAbstract: Data integration has been a long-standing challenge in data management with many applications. A key step in data integration is entity consolidation. It takes a collection of clusters of duplicate records as input and produces a single \\\"golden record\\\" for each cluster, which contains the canonical value for each attribute. Truth discovery and data fusion methods as well as Master Data Management (MDM) systems can be used for entity consolidation. However, to achieve better results, the variant values (i.e., values that are logically the same with different formats) in the clusters need to be consolidated before applying these methods. For this purpose, we propose a data-driven method to standardize the variant values based on two observations: (1) the variant values usually can be transformed to the same representation (e.g., \\\"Mary Lee\\\" and \\\"Lee, Mary\\\") and (2) the same transformation often appears repeatedly across different clusters (e.g., transpose the first and last name). Our approach first uses an unsupervised method to generate groups of value pairs that can be transformed in the same way. Then the groups are presented to a human for verification and the approved ones are used to standardize the data. In a real-world dataset with 17,497 records, our method achieved 75% recall and 99.5% precision in standardizing variant values by asking a human 100 yes/no questions, which completely outperformed a state of the art data wrangling tool.\",\n \"Title: Termite: a system for tunneling through heterogeneous data\\nYear: 2019\\n\\nAbstract: Data-driven analysis is important in virtually every modern organization. Yet, most data is underutilized because it remains locked in silos inside of organizations; large organizations have thousands of databases, and billions of files that are not integrated together in a single, queryable repository. Despite 40+ years of continuous effort by the database community, data integration still remains an open challenge.\\n\\nIn this paper, we advocate a different approach: rather than trying to infer a common schema, we aim to find another common representation for diverse, heterogeneous data. Specifically, we argue for an embedding (i.e., a vector space) in which all entities, rows, columns, and paragraphs are represented as points. In the embedding, the distance between points indicates their degree of relatedness. We present Termite, a prototype we have built to learn the best embedding from the data. Because the best representation is learned, this allows Termite to avoid much of the human effort associated with traditional data integration tasks. On top of Termite, we have implemented a Termite-Join operator, which allows people to identify related concepts, even when these are stored in databases with different schemas and in unstructured data such as text files, webpages, etc. Finally, we show preliminary evaluation results of our prototype via a user study, and describe a list of future directions we have identified.\",\n \"Title: SysML: The New Frontier of Machine Learning Systems.\\nYear: 2019\\n\\nAbstract: Machine learning (ML) techniques are enjoying rapidly increasing adoption. However, designing and implementing the systems that support ML models in real-world deployments remains a significant obstacle, in large part due to the radically different development and deployment profile of modern ML methods, and the range of practical concerns that come with broader adoption. We propose to foster a new systems machine learning research community at the intersection of the traditional systems and ML communities, focused on topics such as hardware systems for ML, software systems for ML, and ML optimized for metrics beyond predictive accuracy. To do this, we describe a new conference, SysML, that explicitly targets research at the intersection of systems and machine learning with a program committee split evenly between experts in systems and ML, and an explicit focus on topics at the intersection of the two.\",\n \"Title: SCAR: Strong Consistency using Asynchronous Replication with Minimal Coordination.\\nYear: 2019\\n\\nAbstract: Data replication is crucial in modern distributed systems as a means to provide high availability. Many techniques have been proposed to utilize replicas to improve a systemu0027s performance, often requiring expensive coordination or sacrificing consistency. In this paper, we present SCAR, a new distributed and replicated in-memory database that allows serializable transactions to read from backup replicas with minimal coordination. SCAR works by assigning logical timestamps to database records so that a transaction can safely read from a backup replica without coordinating with the primary replica, because the records cannot be changed up to a certain logical time. In addition, we propose two optimization techniques, timestamp synchronization and parallel locking and validation, to further reduce coordination. We show that SCAR outperforms systems with conventional concurrency control algorithms and replication strategies by up to a factor of 2 on three popular benchmarks. We also demonstrate that SCAR achieves higher throughput by running under reduced isolation levels and detects concurrency anomalies in real time.\",\n \"Title: Deductive Optimization of Relational Data Storage.\\nYear: 2019\\n\\nAbstract: Optimizing the physical data storage and retrieval of data are two key database management problems. In this paper, we propose a language that can express both a relational query and the layout of its data. Our language can express a wide range of physical database layouts, going well beyond the row- and column-based methods that are widely used in database management systems. We use deductive program synthesis to turn a high-level relational representation of a database query into a highly optimized low-level implementation which operates on a specialized layout of the dataset. We build an optimizing compiler for this language and conduct experiments using a popular database benchmark, which shows that the performance of our specialized queries is better than a state-of-the-art in memory compiled database system while achieving an order-of-magnitude reduction in memory use.\",\n \"Title: Lazo: A Cardinality-Based Method for Coupled Estimation of Jaccard Similarity and Containment\\nYear: 2019\\n\\nAbstract: Data analysts often need to find datasets that are similar (i.e., have high overlap) or that are subsets of one another (i.e., one contains the other). Exactly computing such relationships is expensive because it entails an all-pairs comparison between all values in all datasets, an O(n2) operation. Fortunately, it is possible to obtain approximate solutions much faster, using locality sensitive hashing (LSH). Unfortunately, LSH does not lend itself naturally to compute containment, and only returns results with a similarity beyond a pre-defined threshold; we want to know the specific similarity and containment score. The main contribution of this paper is LAZO, a method to simultaneously estimate both the similarity and containment of datasets, based on a redefinition of Jaccard similarity which takes into account the cardinality of each set. In addition, we show how to use the method to improve the quality of the original JS and JC estimates. Last, we implement LAZO as a new indexing structure that has these additional properties: i) it returns numerical scores to indicate the degree of similarity and containment between each candidate and the query—instead of only returning the candidate set; ii) it permits to query for a specific threshold on-the-fly, as opposed to LSH indexes that need to be configured with a pre-defined threshold a priori; iii) it works in a data-oblivious way, so it can be incrementally maintained. We evaluate LAZO on real-world datasets and show its ability to estimate containment and similarity better and faster than existing methods.\",\n \"Title: Raha: A Configuration-Free Error Detection System\\nYear: 2019\\n\\nAbstract: Detecting erroneous values is a key step in data cleaning. Error detection algorithms usually require a user to provide input configurations in the form of rules or statistical parameters. However, providing a complete, yet correct, set of configurations for each new dataset is not trivial, as the user has to know about both the dataset and the error detection algorithms upfront. In this paper, we present Raha, a new configuration-free error detection system. By generating a limited number of configurations for error detection algorithms that cover various types of data errors, we can generate an expressive feature vector for each tuple value. Leveraging these feature vectors, we propose a novel sampling and classification scheme that effectively chooses the most representative values for training. Furthermore, our system can exploit historical data to filter out irrelevant error detection algorithms and configurations. In our experiments, Raha outperforms the state-of-the-art error detection techniques with no more than 20 labeled tuples on each dataset.\",\n \"Title: Efficient discovery of sequence outlier patterns\\nYear: 2019\\n\\nAbstract: Modern Internet of Things (IoT) applications generate massive amounts of time-stamped data, much of it in the form of discrete, symbolic sequences. In this work, we present a new system called TOP that de<u>T</u>ects <u>O</u>utlier <u>P</u>atterns from these sequences. To solve the fundamental limitation of existing pattern mining semantics that miss outlier patterns hidden inside of larger frequent patterns, TOP offers new pattern semantics based on contextual patterns that distinguish the independent occurrence of a pattern from its occurrence as part of its super-pattern. We present efficient algorithms for the mining of this new class of contextual patterns. In particular, in contrast to the bottom-up strategy for state-of-the-art pattern mining techniques, our top-down Reduce strategy piggy backs pattern detection with the detection of the context in which a pattern occurs. Our approach achieves linear time complexity in the length of the input sequence. Effective optimization techniques such as context-driven search space pruning and inverted index-based outlier pattern detection are also proposed to further speed up contextual pattern mining. Our experimental evaluation demonstrates the effectiveness of TOP at capturing meaningful outlier patterns in several real-world IoT use cases. We also demonstrate the efficiency of TOP, showing it to be up to 2 orders of magnitude faster than adapting state-of-the-art mining to produce this new class of contextual outlier patterns, allowing us to scale outlier pattern mining to large sequence datasets.\",\n \"Title: Technical Report: Optimizing Human Involvement for Entity Matching and Consolidation.\\nYear: 2019\\n\\nAbstract: An end-to-end data integration system requires human feedback in several phases, including collecting training data for entity matching, debugging the resulting clusters, confirming transformations applied on these clusters for data standardization, and finally, reducing each cluster to a single, canonical representation (or \\\"golden record\\\"). The traditional wisdom is to sequentially apply the human feedback, obtained by asking specific questions, within some budget in each phase. However, these questions are highly correlated; the answer to one can influence the outcome of any of the phases of the pipeline. Hence, interleaving them has the potential to offer significant benefits. In this paper, we propose a human-in-the-loop framework that interleaves different types of questions to optimize human involvement. We propose benefit models to measure the quality improvement from asking a question, and cost models to measure the human time it takes to answer a question. We develop a question scheduling framework that judiciously selects questions to maximize the accuracy of the final golden records. Experimental results on three real-world datasets show that our holistic method significantly improves the quality of golden records from 70% to 90%, compared with the state-of-the-art approaches.\",\n \"Title: Asynchronous Prefix Recoverability for Fast Distributed Stores\\nYear: 2021\\n\\nAbstract: ABSTRACTAccessing and updating data sharded across distributed machines safely and speedily in the face of failures remains a challenging problem. Most prominently, applications that share state across different nodes want their writes to quickly become visible to others, without giving up recoverability guarantees in case a failure occurs. Current solutions of a fast cache backed by storage cannot support this use case easily. In this work, we design a distributed protocol, called Distributed Prefix Recovery (DPR) that builds on top of a sharded cache-store architecture with single-key operations, to provide cross-shard recoverability guarantees. With DPR, many clients can read and update shared state at sub-millisecond latency, while receiving periodic prefix durability guarantees. On failure, DPR quickly restores the system to a prefix-consistent state with a novel non-blocking rollback scheme. We added DPR to a key-value store (FASTER) and cache (Redis) and show that we can get high throughput and low latency similar to in-memory systems, while lazily providing durability guarantees similar to persistent stores.\",\n \"Title: ELITE: Robust Deep Anomaly Detection with Meta Gradient\\nYear: 2021\\n\\nAbstract: ABSTRACTDeep Learning techniques have been widely used in detecting anomalies from complex data. Most of these techniques are either unsupervised or semi-supervised because of a lack of a large number of labeled anomalies. However, they typically rely on a clean training data not polluted by anomalies to learn the distribution of the normal data. Otherwise, the learned distribution tends to be distorted and hence ineffective in distinguishing between normal and abnormal data. To solve this problem, we propose a novel approach called ELITE that uses a small number of labeled examples to infer the anomalies hidden in the training samples. It then turns these anomalies into useful signals that help to better detect anomalies from user data. Unlike the classical semi-supervised classification strategy which uses labeled examples as training data, ELITE uses them as validation set. It leverages the gradient of the validation loss to predict if one training sample is abnormal. The intuition is that correctly identifying the hidden anomalies could produce a better deep anomaly model with reduced validation loss. Our experiments on public benchmark datasets show that ELITE achieves up to 30% improvement in ROC AUC comparing to the state-of-the-art, yet robust to polluted training data.\",\n \"Title: LANCET: labeling complex data at scale\\nYear: 2021\\n\\nAbstract: AbstractCutting-edge machine learning techniques often require millions of labeled data objects to train a robust model. Because relying on humans to supply such a huge number of labels is rarely practical, automated methods for label generation are needed. Unfortunately, critical challenges in auto-labeling remain unsolved, including the following research questions: (1) which objects to ask humans to label, (2) how to automatically propagate labels to other objects, and (3) when to stop labeling. These three questions are not only each challenging in their own right, but they also correspond to tightly interdependent problems. Yet existing techniques provide at best isolated solutions to a subset of these challenges. In this work, we propose the first approach, called LANCET, that successfully addresses all three challenges in an integrated framework. LANCET is based on a theoretical foundation characterizing the properties that the labeled dataset must satisfy to train an effective prediction model, namely the Covariate-shift and the Continuity conditions. First, guided by the Covariate-shift condition, LANCET maps raw input data into a semantic feature space, where an unlabeled object is expected to share the same label with its near-by labeled neighbor. Next, guided by the Continuity condition, LANCET selects objects for labeling, aiming to ensure that unlabeled objects always have some sufficiently close labeled neighbors. These two strategies jointly maximize the accuracy of the automatically produced labels and the prediction accuracy of the machine learning models trained on these labels. Lastly, LANCET uses a distribution matching network to verify whether both the Covariate-shift and Continuity conditions hold, in which case it would be safe to terminate the labeling process. Our experiments on diverse public data sets demonstrate that LANCET consistently outperforms the state-of-the-art methods from Snuba to GOGGLES and other baselines by a large margin - up to 30 percentage points increase in accuracy.\",\n \"Title: ATLANTIC: making database differentially private and faster with accuracy guarantee\\nYear: 2021\\n\\nAbstract: AbstractDifferential privacy promises to enable data sharing and general data analytics while protecting individual privacy. Because the private data is often stored in the form of relational database that supports SQL queries, making SQL-based analytics differentially private is thus critical. However, the existing SQL-based differentially private systems either only focus on specific type of SQL queries such as COUNT or substantially modify the database engine, thus obstructing adoption in practice. Worse yet, these systems often do not guarantee the desired accuracy by the applications. In this demonstration, using the driving trace workload from Cambridge Mobile Telematics (CMT), we show that our ATLANTIC system, as a database middleware, enforces differential privacy for real-world SQL queries with provable accuracy guarantees and is compatible with existing databases. Moreover, using a sampling-based technique, ATLANTIC significantly speeds up the query execution, yet effectively amplifying the privacy guarantee.\",\n \"Title: Inferring high-resolution traffic accident risk maps based on satellite imagery and GPS trajectories.\\nYear: 2021\\n\\nAbstract: Traffic accidents cost about 3% of the world's GDP and are the leading cause of death in children and young adults. Accident risk maps are useful tools to monitor and mitigate accident risk. We present a technique to generate high-resolution (5 meters) accident risk maps. At this high resolution, accidents are sparse and risk estimation is limited by bias-variance trade-off. Prior accident risk maps either estimate low-resolution maps that are of low utility (high bias), or they use frequency-based estimation techniques that inaccurately predict where accidents actually happen (high variance). To improve this trade-off, we use an end-to-end deep architecture that can input satellite imagery, GPS trajectories, road maps and the history of accidents. Our evaluation on four metropolitan areas in the US with a total area of 7,488 km2 shows that our technique outperforms prior work in terms of resolution and accuracy.\",\n \"Title: Nonintrusive Measurements for Detecting Progressive Equipment Faults\\nYear: 2022\\n\\nAbstract: The gradual environmental degradation of materials can lead to corrosion and mechanical failures of electrical loads. Vibration and corrosion both contribute to the failure of electrical connections and conductors, and electrical arcs destroy materials in ways that enhance the opportunities for further damage. These failures lead to loss of system capability and the possibility of electrical fires. The signatures of these impending electrical failures, which may occur over weeks or months, can be detected in many systems through nonintrusive electrical monitoring. This article demonstrates techniques for decoding the type of electrical signatures that lead to progressive failure. Example applications of these techniques are illustrated with observations of the degradation and failure of copper-sheathed jacket water (JW) heaters aboard a United States Coast Guard (USCG) vessel. Electrical, material, and vibration analysis are presented to demonstrate the basis for diagnostic electrical signatures.\",\n \"Title: OTIF: Efficient Tracker Pre-processing over Large Video Datasets\\nYear: 2022\\n\\nAbstract: Performing analytics tasks over large-scale video datasets is increasingly common in a wide range of applications, from traffic planning to sports analytics. These tasks generally involve object detection and tracking operations that require pre-processing the video through expensive machine learning models. To address this cost, several video query optimizers have recently been proposed. Broadly, these methods trade large reductions in pre-processing cost for increases in query execution cost: during query execution, they apply query-specific machine learning operations over portions of the video dataset. Although video query optimizers reduce the overall cost of executing a single query over large video datasets compared to naive object tracking methods, executing several queries over the same video remains cost-prohibitive; moreover, the high per-query latency makes these systems unsuitable for exploratory analytics where fast response times are crucial. In this paper, we present OTIF, a video pre-processor that efficiently extracts all object tracks from large-scale video datasets. By integrating several optimizations under a joint parameter tuning framework, OTIF is able to extract all object tracks from video as fast as existing video query optimizers can execute just one single query. In contrast to the outputs of video query optimizers, OTIF's outputs are general-purpose object tracks that can be used to execute many queries with sub-second latencies. We compare OTIF against three recent video query optimizers, as well as several general-purpose object detection and tracking techniques, and find that, across multiple datasets, OTIF provides a 6x to 25x average reduction in the overall cost to execute five queries over the same video.\",\n \"Title: Tile-based Lightweight Integer Compression in GPU\\nYear: 2022\\n\\nAbstract: GPUs are increasingly used for high-performance and interactive data analytics workloads due to their capability to accelerate computation using massive parallelism. A key constraint of GPU-based data analytics today is the limited memory capacity in GPU devices. Data compression is a powerful technique that can mitigate the capacity limitation in two ways: (1) fitting more data into GPU memory and (2) speeding up data transfer between CPU and GPU. However, compression schemes for GPU today are still limited in compression ratio and/or decompression speed. We identify two limiting factors of existing approaches. First, existing decompression solutions require multiple passes of scanning the global memory to decode layers of compression schemes, incurring significant memory traffic and hurting performance. We present the tile-based decompression model to decompress encoded data in a single pass over global memory and inline with query execution. Second, we develop an efficient implementation of bit-packing-based compression schemes and their optimization techniques in the context of GPU. Our evaluation shows that our schemes can achieve similar compression rates to the best state-of-the-art compression schemes in GPU (i.e., nvCOMP) while being 2.2x and 2.6x faster in decompression speed and query running time.\",\n \"Title: Replicated Layout for In-Memory Database Systems\\nYear: 2021\\n\\nAbstract: Scanning and filtering are the foundations of analytical database systems. Modern DBMSs employ a variety of techniques to partition and layout data to improve the performance of these operations. To accelerate query performance, systems tune data layout to reduce the cost of accessing and processing data. However, these layouts optimize for the average query, and with heterogeneous data access patterns in parts of the data, their performance degrades. To mitigate this, we present CopyRight, a layout-aware partial replication engine that replicates parts of the data differently and lays out each replica differently to maximize the overall query performance. Across a range of real-world query workloads, CopyRight is able to achieve 1.1X to 7.9X faster performance than the best non-replicated layout with 0.25X space overhead. When compared to full table replication with 100% overhead, CopyRight attains the same or up to 5.2X speedup with 25% space overhead.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":174,"string":"174"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13372,"string":"13,372"}}},{"rowIdx":13373,"cells":{"question_id":{"kind":"string","value":"Duan Yu Chen"},"question":{"kind":"string","value":"Generate an abstract for the title \"Motion Activity Based Shot Identification and Closed Caption Detection for Video Structuring\" using the following items: 1. Video content generation \n2. Shot description \n3. Closed caption detection \n4. Object-based motion activity descriptor \n5. Hierarchical structuring."},"answer":{"kind":"string","value":"In this paper, we propose a novel approach to generate the table of video content based on shot description by motion activity and closed caption in MPEG-2 video streams. Videos are segmented into shots by GOP-based approach and shot identification is used to identify segmented shots. The specific shots of interest are selected and the proposed approach of closed caption detection is used to detect captions in these shots. In order to speed up in scene change detection, instead of examining scene cut frame by frame, GOP-based approach first checks video streams GOP by GOP and then finds out the actual scene boundaries in the frame level. The segmented shots containing closed caption are identified by the proposed object-based motion activity descriptor. The algorithm of SOM (Self-Organization Map) is used to filter out noise in the process of caption localization. While captions are localized in the recognized shots, we create the table of video content based on the hierarchical structure of story unit, consecutive shots and captioned frames. The experimental results show the effectiveness of the proposed approach and reveal the feasibility of the hierarchical structuring of video content."},"correct_answer":{"kind":"string","value":"In this paper, we propose a novel approach to generate the table of video content based on shot description by motion activity and closed caption in MPEG-2 video streams. Videos are segmented into shots by GOP-based approach and shot identification is used to identify segmented shots. The specific shots of interest are selected and the proposed approach of closed caption detection is used to detect captions in these shots. In order to speed up in scene change detection, instead of examining scene cut frame by frame, GOP-based approach first checks video streams GOP by GOP and then finds out the actual scene boundaries in the frame level. The segmented shots containing closed caption are identified by the proposed object-based motion activity descriptor. The algorithm of SOM (Self-Organization Map) is used to filter out noise in the process of caption localization. While captions are localized in the recognized shots, we create the table of video content based on the hierarchical structure of story unit, consecutive shots and captioned frames. The experimental results show the effectiveness of the proposed approach and reveal the feasibility of the hierarchical structuring of video content."},"documents":{"kind":"list like","value":["Title: Visual-based spatiotemporal analysis for nighttime vehicle braking event detection\nYear: 2012\n\nAbstract: In this paper, we propose a novel visual-based approach that can detect brake lights at night by analyzing the tail lights based on the thee-dimensional Nakagami imaging which can provide robust information of brake lights. Instead of using the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on extracting the invariant features based on modeling the scattering of brake lights and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.","Title: Continuous Human Action Segmentation and Recognition Using a Spatio-Temporal Probabilistic Framework\nYear: 2006\n\nAbstract: In this paper, a framework of automatic human action segmentation and recognition in continuous action sequences is proposed. A star-like figure is proposed to effectively represent the extremities in the silhouette of human body. The human action, thus, is recorded as a sequence of the star-like figure parameters, which is used for action modeling. To model human actions in a compact manner while characterizing their spatio-temporal distributions, star-like figure parameters are represented by Gaussian mixture models (GMM). In addition, to address the intrinsic nature of temporal variations in a continuous action sequence, we transform the time sequence of star-like figure parameters into frequency domain by discrete cosine transform (DCT) and use only the first few coefficients to represent different temporal patterns with significant discriminating power. The performance shows that the proposed framework can recognize continuous human actions in an efficient way.","Title: Cross-view object identification using principal color transformation\nYear: 2010\n\nAbstract: This paper presents a novel color correction technique for object identification across different cameras. First of all, we project the analyzed object onto the LAB color space and then find its principal color axis through the principal component analysis. Since the L axis corresponds to the intensity, we then rotate the found principal color axis for making it parallel to the L axis. After this rotation, the color distortions among different cameras can be reduced into minimum. Then, a hybrid classifier is designed for classifying objects into different categories even though they are captured under different lighting conditions. Based on a polar coordinate, a sampling technique is then proposed for extracting several important color features from AB plane. Then, using the SVM learning algorithm, a color classifier can be trained for classifying each object into different categories. For the non-color categories, we quantize the RGB channels into different levels. Then, another classifier is obtained for classifying each gray object into its corresponding category. Since the proposed color correction scheme reduce the problem of color distortions into a minimum, each object can be well classified and identified even though they are captured across different cameras and under lighting condition.","Title: Vehicle Color Classification Under Different Lighting Conditions Through Color Correction\nYear: 2012\n\nAbstract: This paper presents a novel vehicle color classification technique for classifying vehicles into seven categories under different lighting conditions via color correction. First, to reduce lighting effects, a mapping function is built to minimize the color distortions between frames. In addition to color distortions, the effect of specular highlights can also make the window of a vehicle appear white and degrade the accuracy of vehicle classification. To reduce this effect, a window-removal task is performed to make vehicle pixels with the same color more concentrated on the analyzed vehicle. Thus, a vehicle can be more accurately classified into its corresponding category even when it is shone by strong sunlight. One major problem in vehicle color classification is that there are many shade colors; for example, white versus silver and black versus navy. Traditional methods lack the ability to classify vehicles with shade colors because a wrong classifier is designed by putting vehicles with the same label together even though their chromatic attributes are different. To treat this problem, a novel tree-based classifier is designed for classifying vehicles into chromatic/nonchromatic classes with their nonchromatic strengths and then into detailed color classes with their color features. The separation can significantly improve the accuracy of vehicle color classification even that vehicles are with various shade colors and captured under different lighting conditions.","Title: Occluded human action analysis using dynamic manifold model\nYear: 2012\n\nAbstract: This paper proposes a novel nonlinear manifold learning method for addressing the ill-posed problem of occluded human action analysis. As we know, a person can perform a broad variety of movements. To capture the multiplicity of a human action, this paper creates a low-dimensional manifold for capturing the intra-path and inter-path contexts of an event. Then, an action path matching scheme can be applied for seeking the best event path for linking the missed information between occluded persons. After that, a recovering scheme is proposed for repairing an occluded object to a complete one. Then, each action can be converted to a series of action primitives through posture analysis. Since occluded objects are handled, there will be many posture-symbol-converting errors. Instead of using a specific symbol, we code a posture using not only its best matched key posture but also its similarities among other key postures. Then, recognition of an action taken from occlude objects can be modeled as a matrix matching problem. With the matrix representation, different actions can be more robustly and effectively matched by comparing their Kullback-Leibler(KL) distances.","Title: An online people counting system for electronic advertising machines\nYear: 2009\n\nAbstract: This paper presents a novel people counting system for an environment in which a stationary camera can count the number of people watching a TV-wall advertisement or an electronic billboard without counting the repetitions in video streams in real time. The people actually watching an advertisement are identified via frontal face detection techniques. To count the number of people precisely, a complementary set of features is extracted from the torso of a human subject, as that part of the body contains relatively richer information than the face. In addition, for conducting robust people recognition, an online classifier trained by Fisher's Linear Discriminant (FLD) strategy is developed. Our experiment results demonstrate the efficacy of the proposed system for the people counting task.","Title: Motion-based unusual event detection in human crowds\nYear: 2011\n\nAbstract: Analyzing human crowds is an important issue in video surveillance and is a challenging task due to their nature of non-rigid shapes. In this paper, optical flows are first estimated and then used for a clue to cluster human crowds into groups in unsupervised manner using our proposed method of adjacency-matrix based clustering (AMC). While the clusters of human crowds are obtained, their behaviors with attributes, orientation, position and crowd size, are characterized by a model of force field. Finally, we can predict the behaviors of human crowds based on the model and then detect if any anomalies of human crowd(s) present in the scene. Experimental results obtained by using extensive dataset show that our system is effective in detecting anomalous events for uncontrolled environment of surveillance videos.","Title: Robust video sequence retrieval using a novel object-based T2D-histogram descriptor\nYear: 2005\n\nAbstract: Due to the tremendous growth in the number of digital videos, the development of video retrieval algorithms that can perform efficient and effective retrieval task is indispensable. In this paper, we propose a high-level motion activity descriptor, object-based transformed 2D-histogram (T2D-histogram), which exploits both spatial and temporal features to characterize video sequences in a semantics-based manner. The discrete cosine transform (DCT) is applied to convert the object-based 2D-histogram sequences from the time domain to the frequency domain. Using this transform, the original high-dimensional time domain features used to represent successive frames are significantly reduced to a set of low-dimensional features in frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to effectively capture the variations of moving objects. Having the efficient scheme for video representation, one can perform video retrieval in an accurate and efficient way.","Title: Automatic Closed Caption Detection and Font Size Differentiation in MPEG Video\nYear: 2002\n\nAbstract: In this paper, a novel approach of automatic closed caption detection and font size differentiation among localized text regions in I-frames of MPEG videos is proposed. The approach consists of five modules: video segmentation, shot selection, caption frame detection, caption localization and font size differentiation. Rather than directly examines scene cut frame by frame, the module of video segmentation first verifies video streams GOP by GOP and then finds out the actual scene boundaries in the frame level. Tennis videos are selected as the case study and the module of shot selection is designed to automatically select specific type of shot for further closed caption detection. The noise of potential captions is filtered out based on its long-term consistency over consecutive frames. While the general closed captions are localized, we select the specific caption that is discriminated utilizing the module of font size differentiation. The detected closed captions can support video structuring, video browsing, high-level video indexing and video content description in MPEG-7. Experimental results show the effectiveness and the feasibility of the proposed scheme.","Title: Content-Aware Video Seam Carving Based on Bag of Visual Cubes\nYear: 2010\n\nAbstract: Carving in consecutive frames with different criteria would usually result in discontinuity of visual perception. Therefore, how to preserve the visual continuity in video frames is the most critical issue in the field of video seam carving. In this paper, we propose a novel approach for modelling dynamic visual attention based on spatio temporal analysis in order to detect the focus of interest automatically. The continuously varied co-sited blocks in a video cube are first detected and their variations are characterized as a bag of visual cubes, which are further employed to determine a proper extent of salient regions in video frames. Once the proper extent through video cubes is determined, the carving process then can be conducted to find the global optimum. Our experiment shows that the proposed content-aware video seam carving based on spatio temporal bag of visual cubes can effectively generate resized videos while keeping their isotropic manipulation and the continuous dynamics of visual perception.","Title: Resource-limited intelligent photo management on mobile platforms\nYear: 2011\n\nAbstract: Apart from wireless communication issues, a key technical challenge is how to achieve the best-experienced photo browsing given the limited screen size of the mobile devices. Therefore, in this paper, we propose a novel technique, resource-limited intelligent photo management (RIPM), on the demand of reducing the complexity of computation on Android mobile platform, in which photos captured are analyzed directly in JPEG compressed domain and are further classified in a real-time manner based on the human subject's gender. In order to make the system robust to luminance variations, DC coefficients are discarded. In addition, for the low-complexity purpose and the effective gender discrimination, a set of AC coefficients are selected automatically based on a three-step dimensionality reduction, in which evaluation of the coefficients' significance is conducted by LDA-based approach. Experimental results obtained by using extensive dataset captured under uncontrolled environments show that our system is effective for photo managements on resource-limited mobile platform.","Title: Salient video cube guided nighttime vehicle braking event detection\nYear: 2012\n\nAbstract: In nighttime driving brake lights are particularly important because they offer a warning signal to prevent potential collisions. In this work, we propose a novel visual-based approach for nighttime brake light detection using three-dimensional Nakagami imaging to analyze tail lights of vehicles in front. Rather than heuristic features, such as symmetry of taillights and appearance of the third brake light, the proposed approach extracts invariant features by modeling the scattering of brake lights, thus allowing detection to proceed in a part-based manner. Experiments from extensive datasets show that the proposed system can effectively detect vehicle braking under different lighting and traffic conditions, making it a realistic option for real-world applications.","Title: An Enhanced Layer Embedded Pedestrian Detector\nYear: 2009\n\nAbstract: We propose a method that can detect pedestrians in a single image based on the combination of Adaboost learning with a local histogram features. Besides, instead of using the raw image for further processing, we introduce a layer enhanced by orientation filters which are superimposed to the original image. Experimental results obtained using the INRIA dataset show the superior performance of our method and thus demonstrate its robustness with the novel enhanced layer embedded pedestrian detector.","Title: A Novel Viewer Counter for Digital Billboards\nYear: 2009\n\nAbstract: This paper presents a novel viewer counter for an environment in which a stationary camera can count the number of people watching an electronic billboard without counting the repetitions in real time video streams. The potential buyers actually watching an advertisement or merchandise are captured via frontal face detection techniques. To count the number of viewer precisely, the problem of occlusions between viewers is tackled. Besides, a complementary set of features is extracted from the torso of a viewer due to the fact that the part of the body contains relatively rich discriminative information than other body parts. In addition, for conducting robust viewer recognition, an online classifier trained by AdaBoost is developed. Our experiment results demonstrate the robustness of the proposed system for the viewer counting task.","Title: Robust video similarity retrieval using temporal MIMB moments\nYear: 2004\n\nAbstract: Due to the tremendous growth in the number of digital videos, the development of video retrieval algorithms that can perform efficient and effective retrieval task is indispensable. In this paper, we propose a high-level motion-pattern descriptor, temporal motion intensity of moving blobs (MIMB) moments, which exploits spatial and temporal features to characterize video sequences in a semantics-based manner. The Discrete Cosine Transform (DCT) is applied to convert the high-level features from the time domain to the frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to precisely capture the variations of moving blobs. Compared to the motion activity descriptors, RLD and SAH in MPEG-7, the proposed descriptor yield 41% and 20% average performance gains over RLD and SAH, respectively. Having the efficient scheme for video representation, one can perform video retrieval in an accurate and efficient way.","Title: Modelling salient visual dynamics in videos\nYear: 2011\n\nAbstract: Automatic video annotation is a critical step for content-based video retrieval and browsing. Detecting the focus of interest in video frames automatically can benefit the tedious manual labeling process. However, producing an appropriate extent of visually salient regions in video sequences is a challenging task. Therefore, in this work, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis. Our model first detects salient points in three-dimensional video volumes, and then uses the points as seeds to search the extent of salient regions in a novel motion attention map. To determine the extent of attended regions, we use the maximum entropy in the spatial domain to analyze the dynamics derived by spatiotemporal analysis. Our experiment results show that the proposed dynamic visual attention model achieves high precision value of 70% and reveals its robustness in successive video volumes.","Title: Preserving Motion-Tolerant Contextual Visual Saliency for Video Resizing\nYear: 2013\n\nAbstract: State of the art video resizing methods usually produce perceivable visual discontinuities, especially in videos containing significant motion. To resolve the problem, contextual information about the focus of interest in consecutive video frames should be considered in order to preserve the visual continuity. In this paper, to detect the focus of interest with motion-tolerance, we propose a novel approach for modelling visual dynamics based on spatiotemporal slices (STS), which provide rich visual patterns along a large temporal scale. First, patch-based visual patterns are computed to generate a codebook of the automatically specified spatiotemporal extent determined by the contextual information in the STS. The codebook is then used to compute its associated response in each video frame, and eventually an importance map covering the focus of interest in a video clip can be obtained. To preserve the visual continuity of the content, particularly an important area, a multi-cue approach is used to guide a mesh-based non-homogeneous warping operation constrained by the trajectories in the STS. For the performance evaluation, we present a novel measure that utilizes patch-based Kullback–Leibler divergence (KL-divergence) to gauge the deformation of the focus of interest under the proposed video resizing approach. Experimental results show that the STS-based approach can generate retargeted videos effectively, while maintaining their isotropic manipulation and the continuous dynamics of visual perception.","Title: Content-aware video resizing based on salient visual cubes\nYear: 2011\n\nAbstract: State of the art methods for video resizing usually produce perceivable visual discontinuities. Therefore, how to preserve the visual continuity in video frames is one of the most critical issues. In this paper, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis in order to detect the focus of interest automatically. The continuously varied co-sited blocks in a video cube are first detected and their variations are characterized as visual cubes, which are further employed to determine a proper extent of salient regions in video frames. Once the proper extent through video cubes is determined, the resizing process then can be conducted to find the global optimum. Our experiment shows that the proposed content-aware video resizing based on spatiotemporal visual cubes can effectively generate resized videos while keeping their isotropic manipulation and the continuous dynamics of visual perception.","Title: Feature Selection for Iris Recognition with AdaBoost\nYear: 2007\n\nAbstract: In this paper, we proposed a method for selecting edge- type features for iris recognition. The AdaBoost algorithm is used to select a filter bank from a pile of filter candi- dates. The decisions of the weak classifiers associated with the filter bank are linearly combined to form a strong clas- sifier. Real experiments have been conducted to assess the performance of the designed strong classifier. The results showed that the boosting algorithm can effectively improve the recognition accuracy at the cost of slightly increase the computation time. Keywords: Iris Recognition, Biometrics, Feature Extrac- tion, AdaBoost.","Title: Automatic Video Summary and Description\nYear: 2000\n\nAbstract: Multimedia technology has been applied to many kinds of applications and the amount of multimedia data is growing dramatically. Especially the usage of digital video data is very popular today. Thus, content-based indexing and retrieval in video is getting more important in the future. In this paper, we investigate an efficient and reasonable solution to describe video contents, and propose an automatic generation of the summary of video contents with as least manual interaction as possible. Based on the summary of video contents, we extract the key features of the summary to represent its content and produce the description of the video content in MPEG-7 format using XML. We illustrate our approach by developing a system that can support content-based browsing and querying on the WWW.","Title: Intelligent Face-Based Mobile Images Categorization.\nYear: 2013\n\nAbstract: Given the increasing number of mobile platforms, a key technical challenge is how to provide an optimal photo browsing experience given the limited screen size available on mobile devices. This paper proposes a novel technique for intelligent mobile image categorization to reduce computation complexity on the Android mobile platform. In this technique, captured images are analyzed directly in JPEG format and then classified in real-time based on the gender of the human subjects appearing in the image. To increase system robustness in various light conditions, DC coefficients are discarded. In addition, to reduce complexity while effectively differentiating subject gender, a set of AC coefficients are automatically selected based on a three-step dimensionality reduction, in which evaluation of the coefficients' significance is conducted by an LDA-based approach. Experimental results obtained using extensive datasets captured under uncontrolled conditions show the proposed system effectively manages photo on resource-limited mobile platforms.","Title: Real-time dynamic vehicle detection on resource-limited mobile platform\nYear: 2012\n\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of cameras and optical devices has made it economically feasible to deploy front-mounted intelligent systems for visual-based event detection. Prior to vehicle event detection, detecting vehicles robustly in real time is challenging, especially conducting detection process in images captured by a dynamic camera. Therefore, in this paper, a robust vehicle detector is developed. Our contribution is three-fold. Road modeling is first proposed to confine detection area for maintaining low computation complexity and reducing false alarms as well. Haar-like features and eigencolors are then employed for the vehicle detector. To tackle the occlusion problem, chamfer distance is used to estimate the probability of each individual vehicle. AdaBoost algorithm is used to select critical features from a combined high dimensional feature set. Experiments on an extensive dataset show that our proposed system can effectively detect vehicles under different lighting and traffic conditions, and thus demonstrates its feasibility in real-world environments.","Title: Nighttime Brake-Light Detection by Nakagami Imaging\nYear: 2012\n\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of cameras and optical devices has made it economically feasible to deploy front-mounted intelligent systems for visual-based event detection for forward collision avoidance and mitigation. While driving at night, vehicles in front are generally visible by their taillights and brake lights. The brake lights are particularly important because they signal deceleration and potential collision. Therefore, in this paper, we propose a novel visual-based approach, based on the Nakagami-$m$ distribution, for detecting brake lights at night by analyzing the taillights. Rather than using the knowledge of the heuristic features, such as the symmetry, position, and size of the rear-facing vehicle, we focus on finding the invariant features to model brake light scattering by Nakagami imaging and therefore conduct the detection process in a part-based manner. Experiments on an extensive data set show that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions and thus demonstrates its feasibility in real-world environments.","Title: Motion Flow-Based Video Retrieval\nYear: 2007\n\nAbstract: In this paper, we propose the use of motion vectors embedded in MPEG bitstreams to generate so-called ldquomotion flowsrdquo, which are applied to perform video retrieval. By using the motion vectors directly, we do not need to consider the shape of a moving object and its corresponding trajectory. Instead, we simply ldquolinkrdquo the local motion vectors across consecutive video frames to form motion flows, which are then recorded and stored in a video database. In the video retrieval phase, we propose a new matching strategy to execute the video retrieval task. Motions that do not belong to the mainstream motion flows are filtered out by our proposed algorithm. The retrieval process can be triggered by query-by-sketch or query-by-example. The experiment results show that our method is indeed superb in the video retrieval process.","Title: Motion Activity Based Semantic Video Similarity Retrieval\nYear: 2002\n\nAbstract: Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. In this paper, a novel mechanism of similarity retrieval is proposed. Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, Discrete Cosine Transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory information and preserves the Euclidean distance between feature vectors. Experiments are performed on MPEG-7 testing videos, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.","Title: Atomic Human Action Segmentation Using a Spatio-Temporal Probabilistic Framework\nYear: 2006\n\nAbstract: In this paper, a framework for automatic atomic human action segmentation in continuous action sequences is proposed A star figure enclosed by a bounding convex polygon is used to effectively and uniquely represent the extremities of the silhouette of a human body. Thus, human actions are recorded as a sequence of the starJigure 's parameters, which is then used for action modeling. To model human actions in a compact manner while characterizing their spatiotemporal distributions, star $@re parameters are represented by Gaussian mixture models (GMM). Experiments to evaluate the performance of the proposed framework show that it can segment continuous human actions in an eficient and effective manner.","Title: Spatiotemporal Motion Analysis for the Detection and Classification of Moving Targets\nYear: 2008\n\nAbstract: This paper presents a video surveillance system in the environment of a stationary camera that can extract moving targets from a video stream in real time and classify them into predefined categories according to their spatiotemporal properties. Targets are detected by computing the pixel-wise difference between consecutive frames, and then classified with a temporally boosted classifier and ldquospatiotemporal-oriented energyrdquo analysis. We demonstrate that the proposed classifier can successfully recognize five types of objects: a person, a bicycle, a motorcycle, a vehicle, and a person with an umbrella. In addition, we process targets that do not match any of the AdaBoost-based classifier's categories by using a secondary classification module that categorizes such targets as crowds of individuals or non-crowds. We show that the above classification task can be performed effectively by analyzing a target's spatiotemporal-oriented energies, which provide a rich description of the target's spatial and dynamic features. Our experiment results demonstrate that the proposed system is extremely effective in recognizing all predefined object classes.","Title: Frequency-Tuned Nighttime Brake-Light Detection\nYear: 2010\n\nAbstract: Advanced safety vehicle (ASV) is a critical issue in recent years for automobiles, especially when the number of vehicles is growing rapidly world wide. The cost down of general cameras makes it feasible to having an intelligent system of visual-based event detection in front for forward collision avoidance and mitigation. When driving in nighttime, vehicles in front are generally visible by their tail and brake lights. The brake lights are particularly important due to their consequent events that drivers need to focus on. Therefore, in this paper, we propose a novel approach that can detect brake lights at night using a camera by analyzing the signal in both spatial and frequency domain. Unlike the traditional approaches that employ the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on finding the invariant features from the regions of brake lights in frequency domain and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can efficiently and effectively detect brake lights under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.","Title: Jointing Edge Labeling and Geometrical Constraint for Lane Detection and its Application to Suspicious Driving Behavior Analysis\nYear: 2011\n\nAbstract: This paper presents a novel lane detection scheme for detecting and tracking various lanes directly from videos in real time. The key contribution of this paper is to propose a new edge labeling scheme for labeling each edge point to different types. Even under different lighting and weather conditions, different lane segments still can be effectively extracted from the labeling result. Only the subtraction and counting operators are involved in the labeling process. It is also flexible for detecting lanes with different types especially from an interchange area. To filter out false lane segments, this paper uses a pinhole camera model to derive a geometrical constraint for lane verification. The constraint is invariant to shadows and lighting changes. Thus, each lane line can be verified and then detected more accurately from roads. Since lanes seldom change their colors during two adjacent frames, we propose a kernel-based technique for tracking them even fragmented into pieces of segments. Then, different lanes can be more efficiently detected and tracked from videos captured under various lighting and weather conditions. With the lane information, different dangerous driving events like lane departure can be easily analyzed for driver assistances. All the involved operations are very simple and effective for hardware implementation. Extensive experimental results reveal the feasibility and superiority of the proposed approach in lane detection.","Title: Vehicle make and model recognition using symmetrical SURF\nYear: 2013\n\nAbstract: SURF (Speeded Up Robust Features) is a robust and useful feature detector for various vision-based applications but lacks the ability to detect symmetrical objects. This paper proposes a new symmetrical SURF descriptor to enrich the power of SURF to detect all possible symmetrical matching pairs through a mirroring transformation. A vehicle make-and-model recognition (MMR) application is then adopted to prove the practicability and feasibility of the method. To detect vehicles from the road, the proposed symmetrical descriptor is first applied to determine the ROI of each vehicle from the road without using any motion features. This scheme provides two advantages; there is no need of background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, i.e., multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To address these two problems, a grid division scheme is proposed to separate a vehicle into several grids; different weak classifiers that are trained on these grids are then integrated to build a strong ensemble classifier. Because of the rich representation power of the grid-based method and the high accuracy of vehicle detection, the ensemble classifier can accurately recognize each vehicle.","Title: Motion-Based Semantic Event Detection for Video Content Description in MPEG-7\nYear: 2001\n\nAbstract: In this paper, we proposed an automatic two-level approach to segment videos into abstracted shots that are semantically meaningful mainly based on inferred video events. In the first level, ew detect scene changes in video sequence into shots. In the second level, each of the shots generated from level-1 is analyzed by utilizing the information of camera operations and object motion that are computed directly from motion vectors of MPEG-2 video streams in compressed domain. Events in tennis videos are than inferred from both object trajectories and applied specific domain knowledge. Video shots are further segmented based on detected video events and hence semantically meaningful video clips can be generated and can assist to annotate video shots, summarize video content, and generate descriptions and description schemes in MPEG-7 standard.","Title: Design of Gabor Filter Banks for Iris Recognition\nYear: 2006\n\nAbstract: In this paper, we propose a systematic approach to design Gabor filter banks for iris feature extraction. The spectra of normalized iris images were analyzed and the most informative band (MIB) was located. When tuning the filter parameters, the pass bands of the filter banks are confined to be within the MIB. It turns out that with the MIB constraint the number of orientation parameters of the Gabor filters can be reduced to one. Furthermore, we show that the spatial locations of the Gabor filters can be arbitrarily and uniformly selected provided that the conditions of the Nyquist sampling theorem are satisfied. The main difficulty of designing filter banks for iris feature extraction is that there are too many free parameters to be determined, e.g., there will be 6N parameters to be designed for N filters. However, after analyzing the possible factors influencing the iris feature extraction process, we found that the free parameters of the Gabor filter banks can be reduced from 6N to three. By using the genetic algorithm to tune the filter parameters, the performance of our recognition system has been gradually improved. The experimental results show that the best equal error rate of our system is about 0.05% computed with the CASIA database.","Title: Dynamic Visual Saliency Modeling for Video Semantics\nYear: 2008\n\nAbstract: In this work, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis. Our model first detects salient points in three-dimensional video volumes, and then uses them as seeds to search the extent of salient regions in a motion attention map. To determine the extent of attended regions, the maximum entropy in the spatial domain is used to analyze the dynamics obtained from spatiotemporal analysis. To annotate video semantics, the extent of attended regions is further recognized as two predefined categories by using orientation filters, cars and people. The experiment results show that the proposed dynamic visual attention model can effectively detect visual saliency through successive video volumes.","Title: Robust gender recognition for real-time surveillance system\nYear: 2010\n\nAbstract: Gender recognition is a challenging task in surveillance videos due to their relatively low-solution, uncontrolled environment and viewing angles of human subject. In this work, a surveillance system of real-time gender recognition is developed. The contribution of this work is four-fold. In order to make the system robust, a mechanism of decision making based on the combination of neighboring face detection, context-regions enhancement and confidence-based weighting assignment is designed. Considering the spatiotemporal consistency of the gender between consecutive faces in successive frames, the belief propagation is employed to model the temporal coherence. Experiment results obtained by using extensive dataset show that our system is effective and efficient in recognizing genders in real-time surveillance videos.","Title: Visual attention guided video copy detection based on feature points matching with geometric-constraint measurement.\nYear: 2013\n\nAbstract: In this paper, to efficiently detect video copies, focus of interests in videos is first localized based on 3D spatiotemporal visual attention modeling. Salient feature points are then detected in visual attention regions. Prior to evaluate similarity between source and target video sequences using feature points, geometric constraint measurement is employed for conducting bi-directional point matching in order to remove noisy feature points and simultaneously maintain robust feature point pairs. Consequently, video matching is transformed to frame-based time-series linear search problem. Our proposed approach achieves promising high detection rate under distinct video copy attacks and thus shows its feasibility in real-world applications. (C) 2013 Elsevier Inc. All rights reserved.","Title: Robust video retrieval using temporal MVMB moments\nYear: 2005\n\nAbstract: In this paper, we propose motion pattern-based descriptor which exploits both spatial and temporal features to characterize video sequences in a semantics-based manner. The Discrete Cosine Transform (DCT) is applied to convert the high-level features from the time domain to the frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to precisely capture the variations of moving blobs. In comparison with the frequently used motion activity descriptors, the RLD and SAH of MPEG-7, the proposed descriptor yields 38% and 19% average gains over RLD and SAH, respectively.","Title: Robust gender recognition for uncontrolled environment of real-life images\nYear: 2010\n\nAbstract: Gender recognition is a challenging task in real life images and surveillance videos due to their relatively low-resolution, under uncontrolled environment and variant viewing angles of human subject. Therefore, in this paper, a system of real-time gender recognition for real life images is proposed. The contribution of this work is three-fold. In order to make the system robust, a mechanism of decision making based on the combination of surrounding face detection, context-regions enhancement and confidence-based weighting assignment is designed. Experiment results obtained by using extensive dataset show that our system is effective and efficient in recognizing genders for uncontrolled environment of real life images.","Title: Face-based multiple instance analysis for smart electronics billboard\nYear: 2012\n\nAbstract: This paper introduces a visual-based system, which can count the number of viewers and recognize their gender in front of an electronic billboard in real-time video streams. The viewers actually watching an advertisement are captured via frontal face detection techniques. To count the number of viewer precisely, the problem of occlusions between viewers is tackled. Besides, a complementary set of features is extracted from the torso of a viewer due to the fact that the part of the body contains relatively rich discriminative information than other body parts. In addition, for conducting robust viewer recognition, an online classifier trained by AdaBoost is developed. To recognize the gender of the counted viewers, an approach based on spatiotemporal probabilistic framework is proposed. Our experimental results demonstrate the robustness of the proposed system for the viewer counting and gender recognition tasks.","Title: Symmetrical SURF and Its Applications to Vehicle Detection and Vehicle Make and Model Recognition\nYear: 2014\n\nAbstract: Speeded-Up Robust Features (SURF) is a robust and useful feature detector for various vision-based applications but it is unable to detect symmetrical objects. This paper proposes a new symmetrical SURF descriptor to enrich the power of SURF to detect all possible symmetrical matching pairs through a mirroring transformation. A vehicle make and model recognition (MMR) application is then adopted to prove the practicability and feasibility of the method. To detect vehicles from the road, the proposed symmetrical descriptor is first applied to determine the region of interest of each vehicle from the road without using any motion features. This scheme provides two advantages: there is no need for background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, namely multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To address these two problems, a grid division scheme is proposed to separate a vehicle into several grids; different weak classifiers that are trained on these grids are then integrated to build a strong ensemble classifier. The histogram of gradient and SURF descriptors are adopted to train the weak classifiers through a support vector machine learning algorithm. Because of the rich representation power of the grid-based method and the high accuracy of vehicle detection, the ensemble classifier can accurately recognize each vehicle.","Title: Human subject-based video browsing and summarization\nYear: 2010\n\nAbstract: To acquire digital videos is much easier than before, since we can get videos captured from DV camcorder. More video archives make searching the targeted content more difficult. In the past decade, efficient video indexing, browsing and summarization techniques thus have become an important research issue in the field of content-based video retrieval. In this work, a novel mechanism of human subject-based browsing and summarization is proposed. Human subjects who are actually watching towards the camera are first detected and are further recognized by our proposed online learning classifiers, which are based on the measure of Mahalanobis distance. A complementary set of features is extracted from the torso of a human subject, as that part of the body contains relatively richer information than the face when the videos are captured in general camcorders. The features extracted from the torso consist of the quadtree-based color features and the quadtree-based edge features. Our experimental results show the efficacy of the proposed system for the human subject-based video browsing and summarization task.","Title: Non-Orthogonal View Iris Recognition System\nYear: 2010\n\nAbstract: This paper proposes a non-orthogonal view iris recognition system comprising a new iris imaging module, an iris segmentation module, an iris feature extraction module and a classification module. A dual-charge-coupled device camera was developed to capture four-spectral (red, green, blue, and near-infrared) iris images which contain useful information for simplifying the iris segmentation task. An intelligent random sample consensus iris segmentation method is proposed to robustly detect iris boundaries in a four-spectral iris image. In order to match iris images acquired at different off-axis angles, we propose a circle rectification method to reduce the off-axis iris distortion. The rectification parameters are estimated using the detected elliptical pupillary boundary. Furthermore, we propose a novel iris descriptor which characterizes an iris pattern with multiscale step/ridge edge-type maps. The edge-type maps are extracted with the derivative of Gaussian and the Laplacian of Gaussian filters. The iris pattern classification is accomplished by edge-type matching which can be understood intuitively with the concept of classifier ensembles. Experimental results show that the equal error rate of our approach is only 0.04% when recognizing iris images acquired at different off-axis angles within ??30??.","Title: Handheld object detection and its related event analysis using ratio histogram and mixture of HMMs\nYear: 2014\n\nAbstract: This paper proposes a novel system to analyze human-object interaction events happening between hands and faces in real time. Two challenging problems in this event analysis must be addressed, i.e., there is no prior knowledge (like shape, color, size, and texture) about the handheld objects, and there are large spatial-temporal variations in event representation. For the first challenge, a novel ratio histogram is proposed to find important color bins to locate handheld objects and their trajectories via a code book technique. This scheme is different from other boosted methods which require very time-consuming estimations to search reliable body configurations. For the second challenge, a mixture of HMMs is proposed to describe an event not only from its dynamic context but also its multiplicity context. It can be performed in real time because an exhaustive search process is avoided to find possible interaction pairs between objects and body parts.","Title: Visual Depth Guided Color Image Rain Streaks Removal Using Sparse Coding\nYear: 2014\n\nAbstract: Rain removal from a single color image is a challenging problem as no temporal information among successive images can be obtained. In this paper, we propose a single-color-image-based rain removal framework by properly formulating rain removal as an image decomposition problem based on sparse representation. In our framework, an input color image is first decomposed into a low-frequency part and a high-frequency part by using the guided image filter so that the rain streaks would be in the high-frequency part with nonrain textures/edges, and the high-frequency part is then decomposed into a rain component and a nonrain component by performing dictionary learning and sparse coding. To separate rain streaks from the high-frequency part, a hybrid feature set, including histogram of oriented gradients, depth of field, and Eigen color, is employed to further decompose the high-frequency part. With the hybrid feature set applied, most rain streaks can be removed; simultaneously nonrain component can be enhanced. To the best of our knowledge, compared with the state-of-the-art approaches, the proposed method is among the first to focus on the problem of single color image rain removal and achieves promising results with not only the rain component being removed more completely, but also the visual quality of restored images being improved.","Title: Vehicle make and model recognition using sparse representation and symmetrical SURFs\nYear: 2015\n\nAbstract: This paper proposes a new symmetrical SURF descriptor to detect vehicles on roads and applies the sparse representation for the application of vehicle make-and-model recognition (MMR). To detect vehicles from roads, this paper proposes a symmetry transformation on SURF points to detect all possible matching pairs of symmetrical SURF points. Then, each desired ROI of vehicle can be located very accurately through a projection technique. This scheme provides two advantages; there is no need of background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, i.e., multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To treat the two problems, a dynamic sparse representation scheme is proposed to represent a vehicle model in an over-complete dictionary whose base elements are the training samples themselves. With the dictionary, a novel Hamming distance classification scheme is proposed to classify vehicle makes and models to detailed classes. Because of the sparsity of sparse representation and the nature of Hamming code highly tolerant to noise, different vehicle makes and models can be recognized extreme accurately.","Title: Visual depth guided image rain streaks removal via sparse coding\nYear: 2012\n\nAbstract: Rain removal from an image is a challenging problem since no motion information can be obtained from successive images. In this work, an input image is first decomposed into low-frequency part and high-frequency part by using guided image filter. So that the rain streaks would be in the high-frequency part with non-rain textures, and then the high-frequency part is decomposed into a “rain component” and a “non-rain component” by performing dictionary learning and sparse coding. To separate rain streaks from high-frequency part, a hybrid feature set is exploited which includes histogram of gradient (HoG) and difference of depth (DoD). With the hybrid feature set applied, most rain streaks can be removed; meanwhile, non-rain components can be enhanced. Compared with the state-of-the-art method [12], our proposed approach shows that not only the rain components can be removed more effectively, but also the visual quality of restored images can be improved.","Title: PLSA-Based Sparse Representation for Object Classification\nYear: 2014\n\nAbstract: This paper proposes a novel object classification method which uses the concept of probabilistic latent semantic analysis (pLSA) to overcome the problem of sparse representation in data classification. Sparse representation is widely used and quite successful in many vision-based applications. However, it needs to calculate the sparse reconstruction cost (SRC) of each sample to find the best candidate. Because an optimization process is involved, it is very inefficient. In addition, it uses only the residual and does not consider the arrangement (or distribution) of combination coefficients of visual codes in classification. Thus, it often fails to classify categories if they are similar. In this paper, the pLSA concept is first introduced into the sparse representation to build a new classifier without using the SRC measure. The weakness of the pLSA scheme is the use of EM algorithm for updating the posteriori probability of latent class. Because it is very time-consuming, a novel weighting voting strategy is introduced to improve the pLSA scheme for recognizing objects in real time. The advantages of this classifier are: the accuracy is much higher than the SRC scheme and the efficiency is real-time in data classification. Two applications are demonstrated in this paper to prove the superiority of the new classifier, i.e., vehicle make and model recognition, and action analysis.","Title: Self-learning-based signal decomposition for multimedia applications: A review and comparative study\nYear: 2014\n\nAbstract: Decomposition of a signal (e.g., image or video) into multiple semantic components has been an effective research topic for various image/video processing applications, such as image/video denoising, enhancement, and inpainting. In this paper, we present a survey of signal decomposition frameworks based on the uses of sparsity and morphological diversity in signal mixtures and its applications in multimedia. First, we analyze existing MCA (morphological component analysis) based image decomposition frameworks with their applications and explore the potential limitations of these approaches for image denoising. Then, we discuss our recently proposed self-learning based image decomposition framework with its applications to several image/video denoising tasks, including single image rain streak removal, denoising, deblocking, joint super-resolution and deblocking for a highly compressed image/video. By advancing sparse representation and morphological diversity of image signals, the proposed framework first learns an over-complete dictionary from the high frequency part of an input image for reconstruction purposes. An unsupervised or supervised clustering technique is applied to the dictionary atoms for identifying the morphological component corresponding to the noise pattern of interest (e.g., rain streaks, blocking artifacts, or Gaussian noises). Different from prior learning-based approaches, our method does not need to collect training data in advance and no image priors are required. Our experimental results have confirmed the effectiveness and robustness of the proposed framework, which has been shown to outperform state-of-the-art approaches.","Title: Wrinkle of fingers based robust person identification\nYear: 2014\n\nAbstract: This paper proposed a novel biometric identification system through 2D fingers' geometry measurements. First, the right middle finger and index finger are captured using a CCD camera. Then the fingers are segmented out from background based on skin colors. Splitting out two fingers based on their contours, multiple features such as the length, mean width, finger shape vector and wrinkle texture are computed and consequently are used for person identification. Experiments show that our proposed method can perform well in real time with the recognition rate being up to 97%.","Title: Region-based hierarchical tongue feature extraction\nYear: 2014\n\nAbstract: Tongue diagnosis is important in the Traditional Chinese Medicine (TCM). When doctors analyze the diseases, they usually observe the patient health base on the shape, color and size of tongue. In order to decrease the mistake of subjective judgment, we aim to develop an automatic tongue feature detection system that can help the doctor diagnosis in more scientific way. In this work, a novel region-based hierarchical filtering framework is proposed to robustly detect tongue features. Experiment results obtained using 14-subject dataset with the detection rate being above 70% shows the effectiveness of our proposed framework.","Title: Sparse coding-based co-salient object detection with application to video abstraction\nYear: 2013\n\nAbstract: Automatic abstraction is important for video retrieval and browsing in a semantic manner. Detecting the focus of interest such as co-occurring objects in video frames automatically can benefit the tedious manual labelling process. However, detecting the co-occurring objects that is visually salient in video sequences is a challenging task. In this paper, in order to detect co-salient video objects efficiently, we first use the preattentive scheme to locate the co-salient regions in video frames and then measure the similarity between salient regions based on KL-divergence. In addition, to update preattentive patch set for co-salient objects, sparse coding is used for dictionary learning and further discrimination among co-salient objects. Finally a set of primary co-salient objects can be found across all video frames using our proposed filtering scheme. As a result, a video sequence can be automatically parsed based on the detection of co-occurring video objects. Our experiment results show that the proposed co-salient video objects modeling achieves high precision value about 85% and reveals its robustness and feasibility in videos.","Title: Real-time traffic light detection on resource-limited mobile platform\nYear: 2014\n\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of intelligent mobile phones has made it economically feasible to develop intelligent systems for visual-based event detection for forward collision avoidance and mitigation. In this work, a real-time traffic red light recognition is proposed under mobile platforms. The proposed method consists of real-time traffic lights localization via image down-sampling, circular regions detection and further traffic lights recognition. Hough Transform is modified to fast localize the traffic light candidates. Finally, a strong classifier is made from multiple weak features is employed for further verifications. In the experiment, the detection rate can achieve above 70%. This shows that our proposed traffic light recognition can be applied in real world environments.","Title: Robust nighttime turn sig nal direction recognition\nYear: 2014\n\nAbstract: In this work, to recognize the direction of turn signals, reflectance is decomposed from the original image. Instead of using heuristic features such as the symmetry, position and size of the rear-view vehicle, we focus on finding the invariant features to model turn signal scattering by scatter properties and then turn signals detection can be performed in a part-based manner. Experiment results with the detection rate above 80% show the effectiveness of the proposed turn signal detector under different lighting and traffic conditions.","Title: Object based video similarity retrieval and its application to detecting anchorperson shots in news video\nYear: 2003\n\nAbstract: Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. A novel mechanism of similarity retrieval is proposed. Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, the discrete cosine transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory information and preserves the Euclidean distance between feature vectors. Experiments are performed on MPEG-7 testing video streams, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.","Title: Robust object detection using cascade filter in MPEG videos\nYear: 2003\n\nAbstract: We propose a novel approach for motion vector (MV) based object detection in MPEG-2 video streams. Rather than processing the extracted MV fields that are directly extracted from MPEG-2 video streams in the compressed domain, we perform MV smoothing, perform MV noise reduction, obtain more robust object information, and refine this information through a cascaded filter composed of a Gaussian filter and a median filter. As a result, the object detection algorithm is more capable of accurately detecting objects. We compare the performance of our proposed system with the popular and commonly used spatial filter processing techniques: median filter, mean filter, Gaussian filter, and no filter. Based on experimental results performed over the MPEG7 testing dataset and measuring performance using the standard recall and precision metrics, object detection using the cascade filter is remarkably superior to the alternative filtering techniques. In addition to these results, we describe a user system interface that we developed, where users can maintain the filter parameters interactively.","Title: Scattering-based brake-light modeling and detection\nYear: 2011\n\nAbstract: Vehicle braking event in front is a critical issue for drivers in general road environments. The cost down of general cameras makes it feasible to having an intelligent system of visual-based detector in front for forward collision avoidance and mitigation. When driving at nighttime, vehicles in front are generally visible by their tail and brake lights. The brake lights are particularly important due to their consequent events that drivers need to focus on. Therefore, in this paper, we propose a novel visual-based approach that can detect brake lights at night by analyzing the tail lights based on the Nakagami-m distribution. Instead of using the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on finding the invariant features modeling the brake lights scattering by Nakagami imaging and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.","Title: Low-cost facial expression on mobile platform\nYear: 2015\n\nAbstract: Facial expressions of a person have been developed widely in many applications. Most of them use many complex algorithms, so they need many computing resources for conduction. In order to perform facial expression on resource-limited mobile platform, we determine to develop a system which is low complexity, high efficiency, real-time execution and no prior-training needed. In this paper, lip's features are applied to classify the human emotion. First, we detect human faces by Haar-like features. Second, the region of mouth is determined by the horizontal projection on the location of face. Third, we determine the corners of lips by using the vertical projection to find the lip boundary. The features extracted are the distance of the mouth's contour and the difference of gray values between upper lip and the half of mouth's height. Finally, the analysis method that we adopt is feature-based approach. We attempt to recognize four expressions, neutral, smile, surprise and sadness. The whole system can be conducted in real time about twenty frames per second. The experiment results show that on average the recognition rate is about 85% and thus reveals its efficacy for real world environment.","Title: PLSA-based sparse representation for vehicle color classification\nYear: 2015\n\nAbstract: This paper proposes a novel vehicle color classification method which uses the concept of probabilistic latent semantic analysis (pLSA) to overcome the problem of sparse representation in data classification. Sparse representation is widely used and quite successful in many vision-based applications. However, it needs to calculate the sparse reconstruction cost (SRC) of each sample to find the best candidate. Because an optimization process is involved, it is very inefficient. In addition, it uses only the residual and does not consider the arrangement (or distribution) of combination coefficients of visual codes in classification. Thus, it often fails to classify categories if they are similar. In this paper, the pLSA concept is first introduced into the sparse representation to build a new classifier without using the SRC measure. The weakness of the pLSA scheme is the use of EM algorithm for updating the posteriori probability of latent class. Because it is very time-consuming, a novel weighting voting strategy is introduced to improve the pLSA scheme for recognizing objects in real time. The advantages of this classifier are: the accuracy is much higher than the SRC scheme and the efficiency is real-time in data classification. Vehicle color classification is demonstrated in this paper to prove the superiority of the new classifier.","Title: Automatic Human Target Detection and Remote Respiratory Rate Monitoring\nYear: 2016\n\nAbstract: Contact measurements of the respiratory rate by using whether conventional electrocardiogram (ECG) equipment or gas sensors with chest straps would cause inconvenience for patients. Therefore, a novel image-based non-contact technique is developed for respiratory rate evaluation and human target detection based on image depth information is also proposed to achieve automatic human target searching and respiration monitoring.","Title: A Robust Vision-Based Heart Rate Evaluation.\nYear: 2014\n\nAbstract: Monitoring heart rates using conventional electrocardiogram (ECG) equipment requires patients to wear adhesive gel patches or chest straps that can cause skin irritation and discomfort. Commercially-available pulse oximetry sensors that attach to the fingertips or earlobes also cause inconvenience for patients and the spring-loaded clips can be painful to use. Therefore, a novel robust face-based heart rate monitoring technique is proposed to allow for the evaluation of heart rate variation without physical contact with the patient. Face reflectance is first decomposed from a single image and then heart rate evaluation is conducted from consecutive frames according to the periodic variation of reflectance strength resulting from changes to hemoglobin absorptivity across the visible light spectrum as heartbeats cause changes to blood volume in the blood vessels in the face. To achieve a robust evaluation, ensemble empirical mode decomposition (EEMD) of the Hilbert-Huang Transform (HHT) is used to acquire the primary heart rate signal while reducing the effect of ambient light changes. Our proposed approach is found to outperform the current stateo-f-the-art, providing greater measurement accuracy with smaller variance and is shown to be feasible in real-world environments.","Title: Trainable spectral difference learning with spatial starting for hyperspectral image denoising.\nYear: 2018\n\nAbstract: Because of the limited reflected energy and incoming illumination in an individual band, the reflected energy captured by a hyperspectral sensor might be low and there is inevitable noise that significantly decreases the performance of the subsequent analysis. Denoising is therefore of first importance in hyperspectral image (HSI) analysis and interpretation. However, most HSI denoising methods remove noise with the important spectral information being severely distorted. This paper presents an HSI denoising method using trainable spectral difference learning with spatial initialization (called HDnTSDL) aimed at preserving the spectral information. In the proposed HDnTSDL model, a key band is automatically selected and denoised. The denoised key band acts as a starting point to reconstruct the rest of the non-key bands. Meanwhile, a deep convolutional neural network (CNN) with trainable non-linearity functions is proposed to learn the spectral difference mapping. Then, the rest of the non-key bands are denoised under the guidance of the learned spectral difference with the key band as a starting point. Experiments have been conducted on five databases with both indoor and outdoor scenes. Comparative analyses validate that the proposed method: (i) presents superior performance in spatial recovery and spectral preservation, and (ii) requires less computational time than state-of-the-art methods."],"string":"[\n \"Title: Visual-based spatiotemporal analysis for nighttime vehicle braking event detection\\nYear: 2012\\n\\nAbstract: In this paper, we propose a novel visual-based approach that can detect brake lights at night by analyzing the tail lights based on the thee-dimensional Nakagami imaging which can provide robust information of brake lights. Instead of using the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on extracting the invariant features based on modeling the scattering of brake lights and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.\",\n \"Title: Continuous Human Action Segmentation and Recognition Using a Spatio-Temporal Probabilistic Framework\\nYear: 2006\\n\\nAbstract: In this paper, a framework of automatic human action segmentation and recognition in continuous action sequences is proposed. A star-like figure is proposed to effectively represent the extremities in the silhouette of human body. The human action, thus, is recorded as a sequence of the star-like figure parameters, which is used for action modeling. To model human actions in a compact manner while characterizing their spatio-temporal distributions, star-like figure parameters are represented by Gaussian mixture models (GMM). In addition, to address the intrinsic nature of temporal variations in a continuous action sequence, we transform the time sequence of star-like figure parameters into frequency domain by discrete cosine transform (DCT) and use only the first few coefficients to represent different temporal patterns with significant discriminating power. The performance shows that the proposed framework can recognize continuous human actions in an efficient way.\",\n \"Title: Cross-view object identification using principal color transformation\\nYear: 2010\\n\\nAbstract: This paper presents a novel color correction technique for object identification across different cameras. First of all, we project the analyzed object onto the LAB color space and then find its principal color axis through the principal component analysis. Since the L axis corresponds to the intensity, we then rotate the found principal color axis for making it parallel to the L axis. After this rotation, the color distortions among different cameras can be reduced into minimum. Then, a hybrid classifier is designed for classifying objects into different categories even though they are captured under different lighting conditions. Based on a polar coordinate, a sampling technique is then proposed for extracting several important color features from AB plane. Then, using the SVM learning algorithm, a color classifier can be trained for classifying each object into different categories. For the non-color categories, we quantize the RGB channels into different levels. Then, another classifier is obtained for classifying each gray object into its corresponding category. Since the proposed color correction scheme reduce the problem of color distortions into a minimum, each object can be well classified and identified even though they are captured across different cameras and under lighting condition.\",\n \"Title: Vehicle Color Classification Under Different Lighting Conditions Through Color Correction\\nYear: 2012\\n\\nAbstract: This paper presents a novel vehicle color classification technique for classifying vehicles into seven categories under different lighting conditions via color correction. First, to reduce lighting effects, a mapping function is built to minimize the color distortions between frames. In addition to color distortions, the effect of specular highlights can also make the window of a vehicle appear white and degrade the accuracy of vehicle classification. To reduce this effect, a window-removal task is performed to make vehicle pixels with the same color more concentrated on the analyzed vehicle. Thus, a vehicle can be more accurately classified into its corresponding category even when it is shone by strong sunlight. One major problem in vehicle color classification is that there are many shade colors; for example, white versus silver and black versus navy. Traditional methods lack the ability to classify vehicles with shade colors because a wrong classifier is designed by putting vehicles with the same label together even though their chromatic attributes are different. To treat this problem, a novel tree-based classifier is designed for classifying vehicles into chromatic/nonchromatic classes with their nonchromatic strengths and then into detailed color classes with their color features. The separation can significantly improve the accuracy of vehicle color classification even that vehicles are with various shade colors and captured under different lighting conditions.\",\n \"Title: Occluded human action analysis using dynamic manifold model\\nYear: 2012\\n\\nAbstract: This paper proposes a novel nonlinear manifold learning method for addressing the ill-posed problem of occluded human action analysis. As we know, a person can perform a broad variety of movements. To capture the multiplicity of a human action, this paper creates a low-dimensional manifold for capturing the intra-path and inter-path contexts of an event. Then, an action path matching scheme can be applied for seeking the best event path for linking the missed information between occluded persons. After that, a recovering scheme is proposed for repairing an occluded object to a complete one. Then, each action can be converted to a series of action primitives through posture analysis. Since occluded objects are handled, there will be many posture-symbol-converting errors. Instead of using a specific symbol, we code a posture using not only its best matched key posture but also its similarities among other key postures. Then, recognition of an action taken from occlude objects can be modeled as a matrix matching problem. With the matrix representation, different actions can be more robustly and effectively matched by comparing their Kullback-Leibler(KL) distances.\",\n \"Title: An online people counting system for electronic advertising machines\\nYear: 2009\\n\\nAbstract: This paper presents a novel people counting system for an environment in which a stationary camera can count the number of people watching a TV-wall advertisement or an electronic billboard without counting the repetitions in video streams in real time. The people actually watching an advertisement are identified via frontal face detection techniques. To count the number of people precisely, a complementary set of features is extracted from the torso of a human subject, as that part of the body contains relatively richer information than the face. In addition, for conducting robust people recognition, an online classifier trained by Fisher's Linear Discriminant (FLD) strategy is developed. Our experiment results demonstrate the efficacy of the proposed system for the people counting task.\",\n \"Title: Motion-based unusual event detection in human crowds\\nYear: 2011\\n\\nAbstract: Analyzing human crowds is an important issue in video surveillance and is a challenging task due to their nature of non-rigid shapes. In this paper, optical flows are first estimated and then used for a clue to cluster human crowds into groups in unsupervised manner using our proposed method of adjacency-matrix based clustering (AMC). While the clusters of human crowds are obtained, their behaviors with attributes, orientation, position and crowd size, are characterized by a model of force field. Finally, we can predict the behaviors of human crowds based on the model and then detect if any anomalies of human crowd(s) present in the scene. Experimental results obtained by using extensive dataset show that our system is effective in detecting anomalous events for uncontrolled environment of surveillance videos.\",\n \"Title: Robust video sequence retrieval using a novel object-based T2D-histogram descriptor\\nYear: 2005\\n\\nAbstract: Due to the tremendous growth in the number of digital videos, the development of video retrieval algorithms that can perform efficient and effective retrieval task is indispensable. In this paper, we propose a high-level motion activity descriptor, object-based transformed 2D-histogram (T2D-histogram), which exploits both spatial and temporal features to characterize video sequences in a semantics-based manner. The discrete cosine transform (DCT) is applied to convert the object-based 2D-histogram sequences from the time domain to the frequency domain. Using this transform, the original high-dimensional time domain features used to represent successive frames are significantly reduced to a set of low-dimensional features in frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to effectively capture the variations of moving objects. Having the efficient scheme for video representation, one can perform video retrieval in an accurate and efficient way.\",\n \"Title: Automatic Closed Caption Detection and Font Size Differentiation in MPEG Video\\nYear: 2002\\n\\nAbstract: In this paper, a novel approach of automatic closed caption detection and font size differentiation among localized text regions in I-frames of MPEG videos is proposed. The approach consists of five modules: video segmentation, shot selection, caption frame detection, caption localization and font size differentiation. Rather than directly examines scene cut frame by frame, the module of video segmentation first verifies video streams GOP by GOP and then finds out the actual scene boundaries in the frame level. Tennis videos are selected as the case study and the module of shot selection is designed to automatically select specific type of shot for further closed caption detection. The noise of potential captions is filtered out based on its long-term consistency over consecutive frames. While the general closed captions are localized, we select the specific caption that is discriminated utilizing the module of font size differentiation. The detected closed captions can support video structuring, video browsing, high-level video indexing and video content description in MPEG-7. Experimental results show the effectiveness and the feasibility of the proposed scheme.\",\n \"Title: Content-Aware Video Seam Carving Based on Bag of Visual Cubes\\nYear: 2010\\n\\nAbstract: Carving in consecutive frames with different criteria would usually result in discontinuity of visual perception. Therefore, how to preserve the visual continuity in video frames is the most critical issue in the field of video seam carving. In this paper, we propose a novel approach for modelling dynamic visual attention based on spatio temporal analysis in order to detect the focus of interest automatically. The continuously varied co-sited blocks in a video cube are first detected and their variations are characterized as a bag of visual cubes, which are further employed to determine a proper extent of salient regions in video frames. Once the proper extent through video cubes is determined, the carving process then can be conducted to find the global optimum. Our experiment shows that the proposed content-aware video seam carving based on spatio temporal bag of visual cubes can effectively generate resized videos while keeping their isotropic manipulation and the continuous dynamics of visual perception.\",\n \"Title: Resource-limited intelligent photo management on mobile platforms\\nYear: 2011\\n\\nAbstract: Apart from wireless communication issues, a key technical challenge is how to achieve the best-experienced photo browsing given the limited screen size of the mobile devices. Therefore, in this paper, we propose a novel technique, resource-limited intelligent photo management (RIPM), on the demand of reducing the complexity of computation on Android mobile platform, in which photos captured are analyzed directly in JPEG compressed domain and are further classified in a real-time manner based on the human subject's gender. In order to make the system robust to luminance variations, DC coefficients are discarded. In addition, for the low-complexity purpose and the effective gender discrimination, a set of AC coefficients are selected automatically based on a three-step dimensionality reduction, in which evaluation of the coefficients' significance is conducted by LDA-based approach. Experimental results obtained by using extensive dataset captured under uncontrolled environments show that our system is effective for photo managements on resource-limited mobile platform.\",\n \"Title: Salient video cube guided nighttime vehicle braking event detection\\nYear: 2012\\n\\nAbstract: In nighttime driving brake lights are particularly important because they offer a warning signal to prevent potential collisions. In this work, we propose a novel visual-based approach for nighttime brake light detection using three-dimensional Nakagami imaging to analyze tail lights of vehicles in front. Rather than heuristic features, such as symmetry of taillights and appearance of the third brake light, the proposed approach extracts invariant features by modeling the scattering of brake lights, thus allowing detection to proceed in a part-based manner. Experiments from extensive datasets show that the proposed system can effectively detect vehicle braking under different lighting and traffic conditions, making it a realistic option for real-world applications.\",\n \"Title: An Enhanced Layer Embedded Pedestrian Detector\\nYear: 2009\\n\\nAbstract: We propose a method that can detect pedestrians in a single image based on the combination of Adaboost learning with a local histogram features. Besides, instead of using the raw image for further processing, we introduce a layer enhanced by orientation filters which are superimposed to the original image. Experimental results obtained using the INRIA dataset show the superior performance of our method and thus demonstrate its robustness with the novel enhanced layer embedded pedestrian detector.\",\n \"Title: A Novel Viewer Counter for Digital Billboards\\nYear: 2009\\n\\nAbstract: This paper presents a novel viewer counter for an environment in which a stationary camera can count the number of people watching an electronic billboard without counting the repetitions in real time video streams. The potential buyers actually watching an advertisement or merchandise are captured via frontal face detection techniques. To count the number of viewer precisely, the problem of occlusions between viewers is tackled. Besides, a complementary set of features is extracted from the torso of a viewer due to the fact that the part of the body contains relatively rich discriminative information than other body parts. In addition, for conducting robust viewer recognition, an online classifier trained by AdaBoost is developed. Our experiment results demonstrate the robustness of the proposed system for the viewer counting task.\",\n \"Title: Robust video similarity retrieval using temporal MIMB moments\\nYear: 2004\\n\\nAbstract: Due to the tremendous growth in the number of digital videos, the development of video retrieval algorithms that can perform efficient and effective retrieval task is indispensable. In this paper, we propose a high-level motion-pattern descriptor, temporal motion intensity of moving blobs (MIMB) moments, which exploits spatial and temporal features to characterize video sequences in a semantics-based manner. The Discrete Cosine Transform (DCT) is applied to convert the high-level features from the time domain to the frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to precisely capture the variations of moving blobs. Compared to the motion activity descriptors, RLD and SAH in MPEG-7, the proposed descriptor yield 41% and 20% average performance gains over RLD and SAH, respectively. Having the efficient scheme for video representation, one can perform video retrieval in an accurate and efficient way.\",\n \"Title: Modelling salient visual dynamics in videos\\nYear: 2011\\n\\nAbstract: Automatic video annotation is a critical step for content-based video retrieval and browsing. Detecting the focus of interest in video frames automatically can benefit the tedious manual labeling process. However, producing an appropriate extent of visually salient regions in video sequences is a challenging task. Therefore, in this work, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis. Our model first detects salient points in three-dimensional video volumes, and then uses the points as seeds to search the extent of salient regions in a novel motion attention map. To determine the extent of attended regions, we use the maximum entropy in the spatial domain to analyze the dynamics derived by spatiotemporal analysis. Our experiment results show that the proposed dynamic visual attention model achieves high precision value of 70% and reveals its robustness in successive video volumes.\",\n \"Title: Preserving Motion-Tolerant Contextual Visual Saliency for Video Resizing\\nYear: 2013\\n\\nAbstract: State of the art video resizing methods usually produce perceivable visual discontinuities, especially in videos containing significant motion. To resolve the problem, contextual information about the focus of interest in consecutive video frames should be considered in order to preserve the visual continuity. In this paper, to detect the focus of interest with motion-tolerance, we propose a novel approach for modelling visual dynamics based on spatiotemporal slices (STS), which provide rich visual patterns along a large temporal scale. First, patch-based visual patterns are computed to generate a codebook of the automatically specified spatiotemporal extent determined by the contextual information in the STS. The codebook is then used to compute its associated response in each video frame, and eventually an importance map covering the focus of interest in a video clip can be obtained. To preserve the visual continuity of the content, particularly an important area, a multi-cue approach is used to guide a mesh-based non-homogeneous warping operation constrained by the trajectories in the STS. For the performance evaluation, we present a novel measure that utilizes patch-based Kullback–Leibler divergence (KL-divergence) to gauge the deformation of the focus of interest under the proposed video resizing approach. Experimental results show that the STS-based approach can generate retargeted videos effectively, while maintaining their isotropic manipulation and the continuous dynamics of visual perception.\",\n \"Title: Content-aware video resizing based on salient visual cubes\\nYear: 2011\\n\\nAbstract: State of the art methods for video resizing usually produce perceivable visual discontinuities. Therefore, how to preserve the visual continuity in video frames is one of the most critical issues. In this paper, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis in order to detect the focus of interest automatically. The continuously varied co-sited blocks in a video cube are first detected and their variations are characterized as visual cubes, which are further employed to determine a proper extent of salient regions in video frames. Once the proper extent through video cubes is determined, the resizing process then can be conducted to find the global optimum. Our experiment shows that the proposed content-aware video resizing based on spatiotemporal visual cubes can effectively generate resized videos while keeping their isotropic manipulation and the continuous dynamics of visual perception.\",\n \"Title: Feature Selection for Iris Recognition with AdaBoost\\nYear: 2007\\n\\nAbstract: In this paper, we proposed a method for selecting edge- type features for iris recognition. The AdaBoost algorithm is used to select a filter bank from a pile of filter candi- dates. The decisions of the weak classifiers associated with the filter bank are linearly combined to form a strong clas- sifier. Real experiments have been conducted to assess the performance of the designed strong classifier. The results showed that the boosting algorithm can effectively improve the recognition accuracy at the cost of slightly increase the computation time. Keywords: Iris Recognition, Biometrics, Feature Extrac- tion, AdaBoost.\",\n \"Title: Automatic Video Summary and Description\\nYear: 2000\\n\\nAbstract: Multimedia technology has been applied to many kinds of applications and the amount of multimedia data is growing dramatically. Especially the usage of digital video data is very popular today. Thus, content-based indexing and retrieval in video is getting more important in the future. In this paper, we investigate an efficient and reasonable solution to describe video contents, and propose an automatic generation of the summary of video contents with as least manual interaction as possible. Based on the summary of video contents, we extract the key features of the summary to represent its content and produce the description of the video content in MPEG-7 format using XML. We illustrate our approach by developing a system that can support content-based browsing and querying on the WWW.\",\n \"Title: Intelligent Face-Based Mobile Images Categorization.\\nYear: 2013\\n\\nAbstract: Given the increasing number of mobile platforms, a key technical challenge is how to provide an optimal photo browsing experience given the limited screen size available on mobile devices. This paper proposes a novel technique for intelligent mobile image categorization to reduce computation complexity on the Android mobile platform. In this technique, captured images are analyzed directly in JPEG format and then classified in real-time based on the gender of the human subjects appearing in the image. To increase system robustness in various light conditions, DC coefficients are discarded. In addition, to reduce complexity while effectively differentiating subject gender, a set of AC coefficients are automatically selected based on a three-step dimensionality reduction, in which evaluation of the coefficients' significance is conducted by an LDA-based approach. Experimental results obtained using extensive datasets captured under uncontrolled conditions show the proposed system effectively manages photo on resource-limited mobile platforms.\",\n \"Title: Real-time dynamic vehicle detection on resource-limited mobile platform\\nYear: 2012\\n\\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of cameras and optical devices has made it economically feasible to deploy front-mounted intelligent systems for visual-based event detection. Prior to vehicle event detection, detecting vehicles robustly in real time is challenging, especially conducting detection process in images captured by a dynamic camera. Therefore, in this paper, a robust vehicle detector is developed. Our contribution is three-fold. Road modeling is first proposed to confine detection area for maintaining low computation complexity and reducing false alarms as well. Haar-like features and eigencolors are then employed for the vehicle detector. To tackle the occlusion problem, chamfer distance is used to estimate the probability of each individual vehicle. AdaBoost algorithm is used to select critical features from a combined high dimensional feature set. Experiments on an extensive dataset show that our proposed system can effectively detect vehicles under different lighting and traffic conditions, and thus demonstrates its feasibility in real-world environments.\",\n \"Title: Nighttime Brake-Light Detection by Nakagami Imaging\\nYear: 2012\\n\\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of cameras and optical devices has made it economically feasible to deploy front-mounted intelligent systems for visual-based event detection for forward collision avoidance and mitigation. While driving at night, vehicles in front are generally visible by their taillights and brake lights. The brake lights are particularly important because they signal deceleration and potential collision. Therefore, in this paper, we propose a novel visual-based approach, based on the Nakagami-$m$ distribution, for detecting brake lights at night by analyzing the taillights. Rather than using the knowledge of the heuristic features, such as the symmetry, position, and size of the rear-facing vehicle, we focus on finding the invariant features to model brake light scattering by Nakagami imaging and therefore conduct the detection process in a part-based manner. Experiments on an extensive data set show that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions and thus demonstrates its feasibility in real-world environments.\",\n \"Title: Motion Flow-Based Video Retrieval\\nYear: 2007\\n\\nAbstract: In this paper, we propose the use of motion vectors embedded in MPEG bitstreams to generate so-called ldquomotion flowsrdquo, which are applied to perform video retrieval. By using the motion vectors directly, we do not need to consider the shape of a moving object and its corresponding trajectory. Instead, we simply ldquolinkrdquo the local motion vectors across consecutive video frames to form motion flows, which are then recorded and stored in a video database. In the video retrieval phase, we propose a new matching strategy to execute the video retrieval task. Motions that do not belong to the mainstream motion flows are filtered out by our proposed algorithm. The retrieval process can be triggered by query-by-sketch or query-by-example. The experiment results show that our method is indeed superb in the video retrieval process.\",\n \"Title: Motion Activity Based Semantic Video Similarity Retrieval\\nYear: 2002\\n\\nAbstract: Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. In this paper, a novel mechanism of similarity retrieval is proposed. Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, Discrete Cosine Transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory information and preserves the Euclidean distance between feature vectors. Experiments are performed on MPEG-7 testing videos, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.\",\n \"Title: Atomic Human Action Segmentation Using a Spatio-Temporal Probabilistic Framework\\nYear: 2006\\n\\nAbstract: In this paper, a framework for automatic atomic human action segmentation in continuous action sequences is proposed A star figure enclosed by a bounding convex polygon is used to effectively and uniquely represent the extremities of the silhouette of a human body. Thus, human actions are recorded as a sequence of the starJigure 's parameters, which is then used for action modeling. To model human actions in a compact manner while characterizing their spatiotemporal distributions, star $@re parameters are represented by Gaussian mixture models (GMM). Experiments to evaluate the performance of the proposed framework show that it can segment continuous human actions in an eficient and effective manner.\",\n \"Title: Spatiotemporal Motion Analysis for the Detection and Classification of Moving Targets\\nYear: 2008\\n\\nAbstract: This paper presents a video surveillance system in the environment of a stationary camera that can extract moving targets from a video stream in real time and classify them into predefined categories according to their spatiotemporal properties. Targets are detected by computing the pixel-wise difference between consecutive frames, and then classified with a temporally boosted classifier and ldquospatiotemporal-oriented energyrdquo analysis. We demonstrate that the proposed classifier can successfully recognize five types of objects: a person, a bicycle, a motorcycle, a vehicle, and a person with an umbrella. In addition, we process targets that do not match any of the AdaBoost-based classifier's categories by using a secondary classification module that categorizes such targets as crowds of individuals or non-crowds. We show that the above classification task can be performed effectively by analyzing a target's spatiotemporal-oriented energies, which provide a rich description of the target's spatial and dynamic features. Our experiment results demonstrate that the proposed system is extremely effective in recognizing all predefined object classes.\",\n \"Title: Frequency-Tuned Nighttime Brake-Light Detection\\nYear: 2010\\n\\nAbstract: Advanced safety vehicle (ASV) is a critical issue in recent years for automobiles, especially when the number of vehicles is growing rapidly world wide. The cost down of general cameras makes it feasible to having an intelligent system of visual-based event detection in front for forward collision avoidance and mitigation. When driving in nighttime, vehicles in front are generally visible by their tail and brake lights. The brake lights are particularly important due to their consequent events that drivers need to focus on. Therefore, in this paper, we propose a novel approach that can detect brake lights at night using a camera by analyzing the signal in both spatial and frequency domain. Unlike the traditional approaches that employ the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on finding the invariant features from the regions of brake lights in frequency domain and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can efficiently and effectively detect brake lights under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.\",\n \"Title: Jointing Edge Labeling and Geometrical Constraint for Lane Detection and its Application to Suspicious Driving Behavior Analysis\\nYear: 2011\\n\\nAbstract: This paper presents a novel lane detection scheme for detecting and tracking various lanes directly from videos in real time. The key contribution of this paper is to propose a new edge labeling scheme for labeling each edge point to different types. Even under different lighting and weather conditions, different lane segments still can be effectively extracted from the labeling result. Only the subtraction and counting operators are involved in the labeling process. It is also flexible for detecting lanes with different types especially from an interchange area. To filter out false lane segments, this paper uses a pinhole camera model to derive a geometrical constraint for lane verification. The constraint is invariant to shadows and lighting changes. Thus, each lane line can be verified and then detected more accurately from roads. Since lanes seldom change their colors during two adjacent frames, we propose a kernel-based technique for tracking them even fragmented into pieces of segments. Then, different lanes can be more efficiently detected and tracked from videos captured under various lighting and weather conditions. With the lane information, different dangerous driving events like lane departure can be easily analyzed for driver assistances. All the involved operations are very simple and effective for hardware implementation. Extensive experimental results reveal the feasibility and superiority of the proposed approach in lane detection.\",\n \"Title: Vehicle make and model recognition using symmetrical SURF\\nYear: 2013\\n\\nAbstract: SURF (Speeded Up Robust Features) is a robust and useful feature detector for various vision-based applications but lacks the ability to detect symmetrical objects. This paper proposes a new symmetrical SURF descriptor to enrich the power of SURF to detect all possible symmetrical matching pairs through a mirroring transformation. A vehicle make-and-model recognition (MMR) application is then adopted to prove the practicability and feasibility of the method. To detect vehicles from the road, the proposed symmetrical descriptor is first applied to determine the ROI of each vehicle from the road without using any motion features. This scheme provides two advantages; there is no need of background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, i.e., multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To address these two problems, a grid division scheme is proposed to separate a vehicle into several grids; different weak classifiers that are trained on these grids are then integrated to build a strong ensemble classifier. Because of the rich representation power of the grid-based method and the high accuracy of vehicle detection, the ensemble classifier can accurately recognize each vehicle.\",\n \"Title: Motion-Based Semantic Event Detection for Video Content Description in MPEG-7\\nYear: 2001\\n\\nAbstract: In this paper, we proposed an automatic two-level approach to segment videos into abstracted shots that are semantically meaningful mainly based on inferred video events. In the first level, ew detect scene changes in video sequence into shots. In the second level, each of the shots generated from level-1 is analyzed by utilizing the information of camera operations and object motion that are computed directly from motion vectors of MPEG-2 video streams in compressed domain. Events in tennis videos are than inferred from both object trajectories and applied specific domain knowledge. Video shots are further segmented based on detected video events and hence semantically meaningful video clips can be generated and can assist to annotate video shots, summarize video content, and generate descriptions and description schemes in MPEG-7 standard.\",\n \"Title: Design of Gabor Filter Banks for Iris Recognition\\nYear: 2006\\n\\nAbstract: In this paper, we propose a systematic approach to design Gabor filter banks for iris feature extraction. The spectra of normalized iris images were analyzed and the most informative band (MIB) was located. When tuning the filter parameters, the pass bands of the filter banks are confined to be within the MIB. It turns out that with the MIB constraint the number of orientation parameters of the Gabor filters can be reduced to one. Furthermore, we show that the spatial locations of the Gabor filters can be arbitrarily and uniformly selected provided that the conditions of the Nyquist sampling theorem are satisfied. The main difficulty of designing filter banks for iris feature extraction is that there are too many free parameters to be determined, e.g., there will be 6N parameters to be designed for N filters. However, after analyzing the possible factors influencing the iris feature extraction process, we found that the free parameters of the Gabor filter banks can be reduced from 6N to three. By using the genetic algorithm to tune the filter parameters, the performance of our recognition system has been gradually improved. The experimental results show that the best equal error rate of our system is about 0.05% computed with the CASIA database.\",\n \"Title: Dynamic Visual Saliency Modeling for Video Semantics\\nYear: 2008\\n\\nAbstract: In this work, we propose a novel approach for modeling dynamic visual attention based on spatiotemporal analysis. Our model first detects salient points in three-dimensional video volumes, and then uses them as seeds to search the extent of salient regions in a motion attention map. To determine the extent of attended regions, the maximum entropy in the spatial domain is used to analyze the dynamics obtained from spatiotemporal analysis. To annotate video semantics, the extent of attended regions is further recognized as two predefined categories by using orientation filters, cars and people. The experiment results show that the proposed dynamic visual attention model can effectively detect visual saliency through successive video volumes.\",\n \"Title: Robust gender recognition for real-time surveillance system\\nYear: 2010\\n\\nAbstract: Gender recognition is a challenging task in surveillance videos due to their relatively low-solution, uncontrolled environment and viewing angles of human subject. In this work, a surveillance system of real-time gender recognition is developed. The contribution of this work is four-fold. In order to make the system robust, a mechanism of decision making based on the combination of neighboring face detection, context-regions enhancement and confidence-based weighting assignment is designed. Considering the spatiotemporal consistency of the gender between consecutive faces in successive frames, the belief propagation is employed to model the temporal coherence. Experiment results obtained by using extensive dataset show that our system is effective and efficient in recognizing genders in real-time surveillance videos.\",\n \"Title: Visual attention guided video copy detection based on feature points matching with geometric-constraint measurement.\\nYear: 2013\\n\\nAbstract: In this paper, to efficiently detect video copies, focus of interests in videos is first localized based on 3D spatiotemporal visual attention modeling. Salient feature points are then detected in visual attention regions. Prior to evaluate similarity between source and target video sequences using feature points, geometric constraint measurement is employed for conducting bi-directional point matching in order to remove noisy feature points and simultaneously maintain robust feature point pairs. Consequently, video matching is transformed to frame-based time-series linear search problem. Our proposed approach achieves promising high detection rate under distinct video copy attacks and thus shows its feasibility in real-world applications. (C) 2013 Elsevier Inc. All rights reserved.\",\n \"Title: Robust video retrieval using temporal MVMB moments\\nYear: 2005\\n\\nAbstract: In this paper, we propose motion pattern-based descriptor which exploits both spatial and temporal features to characterize video sequences in a semantics-based manner. The Discrete Cosine Transform (DCT) is applied to convert the high-level features from the time domain to the frequency domain. The energy concentration property of DCT allows us to use only a few DCT coefficients to precisely capture the variations of moving blobs. In comparison with the frequently used motion activity descriptors, the RLD and SAH of MPEG-7, the proposed descriptor yields 38% and 19% average gains over RLD and SAH, respectively.\",\n \"Title: Robust gender recognition for uncontrolled environment of real-life images\\nYear: 2010\\n\\nAbstract: Gender recognition is a challenging task in real life images and surveillance videos due to their relatively low-resolution, under uncontrolled environment and variant viewing angles of human subject. Therefore, in this paper, a system of real-time gender recognition for real life images is proposed. The contribution of this work is three-fold. In order to make the system robust, a mechanism of decision making based on the combination of surrounding face detection, context-regions enhancement and confidence-based weighting assignment is designed. Experiment results obtained by using extensive dataset show that our system is effective and efficient in recognizing genders for uncontrolled environment of real life images.\",\n \"Title: Face-based multiple instance analysis for smart electronics billboard\\nYear: 2012\\n\\nAbstract: This paper introduces a visual-based system, which can count the number of viewers and recognize their gender in front of an electronic billboard in real-time video streams. The viewers actually watching an advertisement are captured via frontal face detection techniques. To count the number of viewer precisely, the problem of occlusions between viewers is tackled. Besides, a complementary set of features is extracted from the torso of a viewer due to the fact that the part of the body contains relatively rich discriminative information than other body parts. In addition, for conducting robust viewer recognition, an online classifier trained by AdaBoost is developed. To recognize the gender of the counted viewers, an approach based on spatiotemporal probabilistic framework is proposed. Our experimental results demonstrate the robustness of the proposed system for the viewer counting and gender recognition tasks.\",\n \"Title: Symmetrical SURF and Its Applications to Vehicle Detection and Vehicle Make and Model Recognition\\nYear: 2014\\n\\nAbstract: Speeded-Up Robust Features (SURF) is a robust and useful feature detector for various vision-based applications but it is unable to detect symmetrical objects. This paper proposes a new symmetrical SURF descriptor to enrich the power of SURF to detect all possible symmetrical matching pairs through a mirroring transformation. A vehicle make and model recognition (MMR) application is then adopted to prove the practicability and feasibility of the method. To detect vehicles from the road, the proposed symmetrical descriptor is first applied to determine the region of interest of each vehicle from the road without using any motion features. This scheme provides two advantages: there is no need for background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, namely multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To address these two problems, a grid division scheme is proposed to separate a vehicle into several grids; different weak classifiers that are trained on these grids are then integrated to build a strong ensemble classifier. The histogram of gradient and SURF descriptors are adopted to train the weak classifiers through a support vector machine learning algorithm. Because of the rich representation power of the grid-based method and the high accuracy of vehicle detection, the ensemble classifier can accurately recognize each vehicle.\",\n \"Title: Human subject-based video browsing and summarization\\nYear: 2010\\n\\nAbstract: To acquire digital videos is much easier than before, since we can get videos captured from DV camcorder. More video archives make searching the targeted content more difficult. In the past decade, efficient video indexing, browsing and summarization techniques thus have become an important research issue in the field of content-based video retrieval. In this work, a novel mechanism of human subject-based browsing and summarization is proposed. Human subjects who are actually watching towards the camera are first detected and are further recognized by our proposed online learning classifiers, which are based on the measure of Mahalanobis distance. A complementary set of features is extracted from the torso of a human subject, as that part of the body contains relatively richer information than the face when the videos are captured in general camcorders. The features extracted from the torso consist of the quadtree-based color features and the quadtree-based edge features. Our experimental results show the efficacy of the proposed system for the human subject-based video browsing and summarization task.\",\n \"Title: Non-Orthogonal View Iris Recognition System\\nYear: 2010\\n\\nAbstract: This paper proposes a non-orthogonal view iris recognition system comprising a new iris imaging module, an iris segmentation module, an iris feature extraction module and a classification module. A dual-charge-coupled device camera was developed to capture four-spectral (red, green, blue, and near-infrared) iris images which contain useful information for simplifying the iris segmentation task. An intelligent random sample consensus iris segmentation method is proposed to robustly detect iris boundaries in a four-spectral iris image. In order to match iris images acquired at different off-axis angles, we propose a circle rectification method to reduce the off-axis iris distortion. The rectification parameters are estimated using the detected elliptical pupillary boundary. Furthermore, we propose a novel iris descriptor which characterizes an iris pattern with multiscale step/ridge edge-type maps. The edge-type maps are extracted with the derivative of Gaussian and the Laplacian of Gaussian filters. The iris pattern classification is accomplished by edge-type matching which can be understood intuitively with the concept of classifier ensembles. Experimental results show that the equal error rate of our approach is only 0.04% when recognizing iris images acquired at different off-axis angles within ??30??.\",\n \"Title: Handheld object detection and its related event analysis using ratio histogram and mixture of HMMs\\nYear: 2014\\n\\nAbstract: This paper proposes a novel system to analyze human-object interaction events happening between hands and faces in real time. Two challenging problems in this event analysis must be addressed, i.e., there is no prior knowledge (like shape, color, size, and texture) about the handheld objects, and there are large spatial-temporal variations in event representation. For the first challenge, a novel ratio histogram is proposed to find important color bins to locate handheld objects and their trajectories via a code book technique. This scheme is different from other boosted methods which require very time-consuming estimations to search reliable body configurations. For the second challenge, a mixture of HMMs is proposed to describe an event not only from its dynamic context but also its multiplicity context. It can be performed in real time because an exhaustive search process is avoided to find possible interaction pairs between objects and body parts.\",\n \"Title: Visual Depth Guided Color Image Rain Streaks Removal Using Sparse Coding\\nYear: 2014\\n\\nAbstract: Rain removal from a single color image is a challenging problem as no temporal information among successive images can be obtained. In this paper, we propose a single-color-image-based rain removal framework by properly formulating rain removal as an image decomposition problem based on sparse representation. In our framework, an input color image is first decomposed into a low-frequency part and a high-frequency part by using the guided image filter so that the rain streaks would be in the high-frequency part with nonrain textures/edges, and the high-frequency part is then decomposed into a rain component and a nonrain component by performing dictionary learning and sparse coding. To separate rain streaks from the high-frequency part, a hybrid feature set, including histogram of oriented gradients, depth of field, and Eigen color, is employed to further decompose the high-frequency part. With the hybrid feature set applied, most rain streaks can be removed; simultaneously nonrain component can be enhanced. To the best of our knowledge, compared with the state-of-the-art approaches, the proposed method is among the first to focus on the problem of single color image rain removal and achieves promising results with not only the rain component being removed more completely, but also the visual quality of restored images being improved.\",\n \"Title: Vehicle make and model recognition using sparse representation and symmetrical SURFs\\nYear: 2015\\n\\nAbstract: This paper proposes a new symmetrical SURF descriptor to detect vehicles on roads and applies the sparse representation for the application of vehicle make-and-model recognition (MMR). To detect vehicles from roads, this paper proposes a symmetry transformation on SURF points to detect all possible matching pairs of symmetrical SURF points. Then, each desired ROI of vehicle can be located very accurately through a projection technique. This scheme provides two advantages; there is no need of background subtraction and it is extremely efficient for real-time applications. Two MMR challenges, i.e., multiplicity and ambiguity problems, are then addressed. The multiplicity problem stems from one vehicle model often having different model shapes on the road. The ambiguity problem results from vehicles from different companies often sharing similar shapes. To treat the two problems, a dynamic sparse representation scheme is proposed to represent a vehicle model in an over-complete dictionary whose base elements are the training samples themselves. With the dictionary, a novel Hamming distance classification scheme is proposed to classify vehicle makes and models to detailed classes. Because of the sparsity of sparse representation and the nature of Hamming code highly tolerant to noise, different vehicle makes and models can be recognized extreme accurately.\",\n \"Title: Visual depth guided image rain streaks removal via sparse coding\\nYear: 2012\\n\\nAbstract: Rain removal from an image is a challenging problem since no motion information can be obtained from successive images. In this work, an input image is first decomposed into low-frequency part and high-frequency part by using guided image filter. So that the rain streaks would be in the high-frequency part with non-rain textures, and then the high-frequency part is decomposed into a “rain component” and a “non-rain component” by performing dictionary learning and sparse coding. To separate rain streaks from high-frequency part, a hybrid feature set is exploited which includes histogram of gradient (HoG) and difference of depth (DoD). With the hybrid feature set applied, most rain streaks can be removed; meanwhile, non-rain components can be enhanced. Compared with the state-of-the-art method [12], our proposed approach shows that not only the rain components can be removed more effectively, but also the visual quality of restored images can be improved.\",\n \"Title: PLSA-Based Sparse Representation for Object Classification\\nYear: 2014\\n\\nAbstract: This paper proposes a novel object classification method which uses the concept of probabilistic latent semantic analysis (pLSA) to overcome the problem of sparse representation in data classification. Sparse representation is widely used and quite successful in many vision-based applications. However, it needs to calculate the sparse reconstruction cost (SRC) of each sample to find the best candidate. Because an optimization process is involved, it is very inefficient. In addition, it uses only the residual and does not consider the arrangement (or distribution) of combination coefficients of visual codes in classification. Thus, it often fails to classify categories if they are similar. In this paper, the pLSA concept is first introduced into the sparse representation to build a new classifier without using the SRC measure. The weakness of the pLSA scheme is the use of EM algorithm for updating the posteriori probability of latent class. Because it is very time-consuming, a novel weighting voting strategy is introduced to improve the pLSA scheme for recognizing objects in real time. The advantages of this classifier are: the accuracy is much higher than the SRC scheme and the efficiency is real-time in data classification. Two applications are demonstrated in this paper to prove the superiority of the new classifier, i.e., vehicle make and model recognition, and action analysis.\",\n \"Title: Self-learning-based signal decomposition for multimedia applications: A review and comparative study\\nYear: 2014\\n\\nAbstract: Decomposition of a signal (e.g., image or video) into multiple semantic components has been an effective research topic for various image/video processing applications, such as image/video denoising, enhancement, and inpainting. In this paper, we present a survey of signal decomposition frameworks based on the uses of sparsity and morphological diversity in signal mixtures and its applications in multimedia. First, we analyze existing MCA (morphological component analysis) based image decomposition frameworks with their applications and explore the potential limitations of these approaches for image denoising. Then, we discuss our recently proposed self-learning based image decomposition framework with its applications to several image/video denoising tasks, including single image rain streak removal, denoising, deblocking, joint super-resolution and deblocking for a highly compressed image/video. By advancing sparse representation and morphological diversity of image signals, the proposed framework first learns an over-complete dictionary from the high frequency part of an input image for reconstruction purposes. An unsupervised or supervised clustering technique is applied to the dictionary atoms for identifying the morphological component corresponding to the noise pattern of interest (e.g., rain streaks, blocking artifacts, or Gaussian noises). Different from prior learning-based approaches, our method does not need to collect training data in advance and no image priors are required. Our experimental results have confirmed the effectiveness and robustness of the proposed framework, which has been shown to outperform state-of-the-art approaches.\",\n \"Title: Wrinkle of fingers based robust person identification\\nYear: 2014\\n\\nAbstract: This paper proposed a novel biometric identification system through 2D fingers' geometry measurements. First, the right middle finger and index finger are captured using a CCD camera. Then the fingers are segmented out from background based on skin colors. Splitting out two fingers based on their contours, multiple features such as the length, mean width, finger shape vector and wrinkle texture are computed and consequently are used for person identification. Experiments show that our proposed method can perform well in real time with the recognition rate being up to 97%.\",\n \"Title: Region-based hierarchical tongue feature extraction\\nYear: 2014\\n\\nAbstract: Tongue diagnosis is important in the Traditional Chinese Medicine (TCM). When doctors analyze the diseases, they usually observe the patient health base on the shape, color and size of tongue. In order to decrease the mistake of subjective judgment, we aim to develop an automatic tongue feature detection system that can help the doctor diagnosis in more scientific way. In this work, a novel region-based hierarchical filtering framework is proposed to robustly detect tongue features. Experiment results obtained using 14-subject dataset with the detection rate being above 70% shows the effectiveness of our proposed framework.\",\n \"Title: Sparse coding-based co-salient object detection with application to video abstraction\\nYear: 2013\\n\\nAbstract: Automatic abstraction is important for video retrieval and browsing in a semantic manner. Detecting the focus of interest such as co-occurring objects in video frames automatically can benefit the tedious manual labelling process. However, detecting the co-occurring objects that is visually salient in video sequences is a challenging task. In this paper, in order to detect co-salient video objects efficiently, we first use the preattentive scheme to locate the co-salient regions in video frames and then measure the similarity between salient regions based on KL-divergence. In addition, to update preattentive patch set for co-salient objects, sparse coding is used for dictionary learning and further discrimination among co-salient objects. Finally a set of primary co-salient objects can be found across all video frames using our proposed filtering scheme. As a result, a video sequence can be automatically parsed based on the detection of co-occurring video objects. Our experiment results show that the proposed co-salient video objects modeling achieves high precision value about 85% and reveals its robustness and feasibility in videos.\",\n \"Title: Real-time traffic light detection on resource-limited mobile platform\\nYear: 2014\\n\\nAbstract: Given the rapid expansion of car ownership worldwide, vehicle safety is an increasingly critical issue in the automobile industry. The reduced cost of intelligent mobile phones has made it economically feasible to develop intelligent systems for visual-based event detection for forward collision avoidance and mitigation. In this work, a real-time traffic red light recognition is proposed under mobile platforms. The proposed method consists of real-time traffic lights localization via image down-sampling, circular regions detection and further traffic lights recognition. Hough Transform is modified to fast localize the traffic light candidates. Finally, a strong classifier is made from multiple weak features is employed for further verifications. In the experiment, the detection rate can achieve above 70%. This shows that our proposed traffic light recognition can be applied in real world environments.\",\n \"Title: Robust nighttime turn sig nal direction recognition\\nYear: 2014\\n\\nAbstract: In this work, to recognize the direction of turn signals, reflectance is decomposed from the original image. Instead of using heuristic features such as the symmetry, position and size of the rear-view vehicle, we focus on finding the invariant features to model turn signal scattering by scatter properties and then turn signals detection can be performed in a part-based manner. Experiment results with the detection rate above 80% show the effectiveness of the proposed turn signal detector under different lighting and traffic conditions.\",\n \"Title: Object based video similarity retrieval and its application to detecting anchorperson shots in news video\\nYear: 2003\\n\\nAbstract: Semantic feature extraction of video shots and fast video sequence matching are important and required for efficient retrieval in a large video database. A novel mechanism of similarity retrieval is proposed. Similarity measure between video sequences considering the spatio-temporal variation through consecutive frames is presented. For bridging the semantic gap between low-level features and the rich meaning that users desire to capture, video shots are analyzed and characterized by the high-level feature of motion activity in compressed domain. The extracted features of motion activity are further described by the 2D-histogram that is sensitive to the spatio-temporal variation of moving objects. In order to reduce the dimensions of feature vector space in sequence matching, the discrete cosine transform (DCT) is exploited to map semantic features of consecutive frames to the frequency domain while retains the discriminatory information and preserves the Euclidean distance between feature vectors. Experiments are performed on MPEG-7 testing video streams, and the results of sequence matching show that a few DCT transformed coefficients are adequate and thus reveal the effectiveness of the proposed mechanism of video retrieval.\",\n \"Title: Robust object detection using cascade filter in MPEG videos\\nYear: 2003\\n\\nAbstract: We propose a novel approach for motion vector (MV) based object detection in MPEG-2 video streams. Rather than processing the extracted MV fields that are directly extracted from MPEG-2 video streams in the compressed domain, we perform MV smoothing, perform MV noise reduction, obtain more robust object information, and refine this information through a cascaded filter composed of a Gaussian filter and a median filter. As a result, the object detection algorithm is more capable of accurately detecting objects. We compare the performance of our proposed system with the popular and commonly used spatial filter processing techniques: median filter, mean filter, Gaussian filter, and no filter. Based on experimental results performed over the MPEG7 testing dataset and measuring performance using the standard recall and precision metrics, object detection using the cascade filter is remarkably superior to the alternative filtering techniques. In addition to these results, we describe a user system interface that we developed, where users can maintain the filter parameters interactively.\",\n \"Title: Scattering-based brake-light modeling and detection\\nYear: 2011\\n\\nAbstract: Vehicle braking event in front is a critical issue for drivers in general road environments. The cost down of general cameras makes it feasible to having an intelligent system of visual-based detector in front for forward collision avoidance and mitigation. When driving at nighttime, vehicles in front are generally visible by their tail and brake lights. The brake lights are particularly important due to their consequent events that drivers need to focus on. Therefore, in this paper, we propose a novel visual-based approach that can detect brake lights at night by analyzing the tail lights based on the Nakagami-m distribution. Instead of using the knowledge of the heuristic features, such as symmetry and position of rear facing vehicle, size and so forth, we focus on finding the invariant features modeling the brake lights scattering by Nakagami imaging and therefore can conduct the detection process in a part-based manner. Experiment from extensive dataset shows that our proposed system can effectively detect vehicle braking under different lighting and traffic conditions, and thus prove its feasibility in real-world environments.\",\n \"Title: Low-cost facial expression on mobile platform\\nYear: 2015\\n\\nAbstract: Facial expressions of a person have been developed widely in many applications. Most of them use many complex algorithms, so they need many computing resources for conduction. In order to perform facial expression on resource-limited mobile platform, we determine to develop a system which is low complexity, high efficiency, real-time execution and no prior-training needed. In this paper, lip's features are applied to classify the human emotion. First, we detect human faces by Haar-like features. Second, the region of mouth is determined by the horizontal projection on the location of face. Third, we determine the corners of lips by using the vertical projection to find the lip boundary. The features extracted are the distance of the mouth's contour and the difference of gray values between upper lip and the half of mouth's height. Finally, the analysis method that we adopt is feature-based approach. We attempt to recognize four expressions, neutral, smile, surprise and sadness. The whole system can be conducted in real time about twenty frames per second. The experiment results show that on average the recognition rate is about 85% and thus reveals its efficacy for real world environment.\",\n \"Title: PLSA-based sparse representation for vehicle color classification\\nYear: 2015\\n\\nAbstract: This paper proposes a novel vehicle color classification method which uses the concept of probabilistic latent semantic analysis (pLSA) to overcome the problem of sparse representation in data classification. Sparse representation is widely used and quite successful in many vision-based applications. However, it needs to calculate the sparse reconstruction cost (SRC) of each sample to find the best candidate. Because an optimization process is involved, it is very inefficient. In addition, it uses only the residual and does not consider the arrangement (or distribution) of combination coefficients of visual codes in classification. Thus, it often fails to classify categories if they are similar. In this paper, the pLSA concept is first introduced into the sparse representation to build a new classifier without using the SRC measure. The weakness of the pLSA scheme is the use of EM algorithm for updating the posteriori probability of latent class. Because it is very time-consuming, a novel weighting voting strategy is introduced to improve the pLSA scheme for recognizing objects in real time. The advantages of this classifier are: the accuracy is much higher than the SRC scheme and the efficiency is real-time in data classification. Vehicle color classification is demonstrated in this paper to prove the superiority of the new classifier.\",\n \"Title: Automatic Human Target Detection and Remote Respiratory Rate Monitoring\\nYear: 2016\\n\\nAbstract: Contact measurements of the respiratory rate by using whether conventional electrocardiogram (ECG) equipment or gas sensors with chest straps would cause inconvenience for patients. Therefore, a novel image-based non-contact technique is developed for respiratory rate evaluation and human target detection based on image depth information is also proposed to achieve automatic human target searching and respiration monitoring.\",\n \"Title: A Robust Vision-Based Heart Rate Evaluation.\\nYear: 2014\\n\\nAbstract: Monitoring heart rates using conventional electrocardiogram (ECG) equipment requires patients to wear adhesive gel patches or chest straps that can cause skin irritation and discomfort. Commercially-available pulse oximetry sensors that attach to the fingertips or earlobes also cause inconvenience for patients and the spring-loaded clips can be painful to use. Therefore, a novel robust face-based heart rate monitoring technique is proposed to allow for the evaluation of heart rate variation without physical contact with the patient. Face reflectance is first decomposed from a single image and then heart rate evaluation is conducted from consecutive frames according to the periodic variation of reflectance strength resulting from changes to hemoglobin absorptivity across the visible light spectrum as heartbeats cause changes to blood volume in the blood vessels in the face. To achieve a robust evaluation, ensemble empirical mode decomposition (EEMD) of the Hilbert-Huang Transform (HHT) is used to acquire the primary heart rate signal while reducing the effect of ambient light changes. Our proposed approach is found to outperform the current stateo-f-the-art, providing greater measurement accuracy with smaller variance and is shown to be feasible in real-world environments.\",\n \"Title: Trainable spectral difference learning with spatial starting for hyperspectral image denoising.\\nYear: 2018\\n\\nAbstract: Because of the limited reflected energy and incoming illumination in an individual band, the reflected energy captured by a hyperspectral sensor might be low and there is inevitable noise that significantly decreases the performance of the subsequent analysis. Denoising is therefore of first importance in hyperspectral image (HSI) analysis and interpretation. However, most HSI denoising methods remove noise with the important spectral information being severely distorted. This paper presents an HSI denoising method using trainable spectral difference learning with spatial initialization (called HDnTSDL) aimed at preserving the spectral information. In the proposed HDnTSDL model, a key band is automatically selected and denoised. The denoised key band acts as a starting point to reconstruct the rest of the non-key bands. Meanwhile, a deep convolutional neural network (CNN) with trainable non-linearity functions is proposed to learn the spectral difference mapping. Then, the rest of the non-key bands are denoised under the guidance of the learned spectral difference with the key band as a starting point. Experiments have been conducted on five databases with both indoor and outdoor scenes. Comparative analyses validate that the proposed method: (i) presents superior performance in spatial recovery and spectral preservation, and (ii) requires less computational time than state-of-the-art methods.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":60,"string":"60"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13373,"string":"13,373"}}},{"rowIdx":13374,"cells":{"question_id":{"kind":"string","value":"Fan Zhou"},"question":{"kind":"string","value":"Generate an abstract for the title \"RFID enabled remote structural health monitoring for heavy lifting appliances\" using the following items: 1. Remote Structural Health Monitoring\n2. RFID Wireless Sensor Network\n3. LabVIEW Virtual Instrument\n4. Health Diagnosis Expert System\n5. Real-time Monitoring and Safety Evaluation"},"answer":{"kind":"string","value":"To realize remote structural health monitoring for heavy lifting appliances, e.g., 500t gantry cranes, technologies of RFID wireless sensor network, LabVIEW virtual instrument and health diagnosis expert system are empoyed to establish an integrated system. The system is divided into three layers in logic structures: the data acquisition layer, the network communication layer and the system service layer. In the data acquisition layer, RFID sensors, RFID readers are deployed to collect the structural strains, vibrations, noises and other motion parameters for each monitored object. In the system service layer, monitoring and analysis services and a health diagnose expert system are employed to carry out real-time monitoring and safety evaluation tasks. The data acquisition points connect the centre platform through LabVIEW communication tunnels. As the result of a comparison with the common optics sensing system, the proposed system has merits of wireless, easy to deploy, passive and save energy."},"correct_answer":{"kind":"string","value":"To realize remote structural health monitoring for heavy lifting appliances, e.g., 500t gantry cranes, technologies of RFID wireless sensor network, LabVIEW virtual instrument and health diagnosis expert system are empoyed to establish an integrated system. The system is divided into three layers in logic structures: the data acquisition layer, the network communication layer and the system service layer. In the data acquisition layer, RFID sensors, RFID readers are deployed to collect the structural strains, vibrations, noises and other motion parameters for each monitored object. In the system service layer, monitoring and analysis services and a health diagnose expert system are employed to carry out real-time monitoring and safety evaluation tasks. The data acquisition points connect the centre platform through LabVIEW communication tunnels. As the result of a comparison with the common optics sensing system, the proposed system has merits of wireless, easy to deploy, passive and save energy."},"documents":{"kind":"list like","value":["Title: Motion Trends Detection in Wireless Sensor Networks\nYear: 2012\n\nAbstract: We address the problem of efficient detection of destination-related motion trends in Wireless Sensor Networks (WSN) where tracking is done in collaborative manner among the sensor nodes participating in location detection. In addition to determining a single location, applications may need to detect whether certain properties are true for the (portion of the) entire trajectories. Transmitting the sequence of (location, time) values to a dedicated sink and relying on the sink to detect the validity of the desired properties is a brute-force approach that generates a lot of communication overhead. We present an in-network distributed algorithm for efficient detecting of the Continuously Moving Towards predicate with respect to a given destination that is either a point or a region with polygonal boundary. Our experiments demonstrate that the proposed approaches yield substantial savings when compared to the brute-force one.","Title: Fast inter mode decision based on textural segmentation and correlations for multiview video coding\nYear: 2010\n\nAbstract: Multiview video coding (MVC) plays a critical role in reducing the ultra high data bandwidth of 3-D video. However, the heavy computational complexity of MVC slows down its applications. In this paper, a fast Inter mode decision based on textural segmentation and correlations is presented: Firstly, each frame is segmented into three textural regions based on the correlation between textural complexities and Intra mode Rate-Distortion (RD) costs, and the correlation of Intra mode RD costs between views. Then, by using textural region types and the correlation of Skip mode RD costs between views, an early decision of Skip mode is introduced. Thirdly, by utilizing Inter16×16 mode prediction results and textural region types, the disparity estimation of other Inter modes is selected. Finally, the estimation of Inter8×8 mode can be reduced according to textural region types and motion activity. As compared to the full mode decision in MVC reference software, experimental results show that the proposed algorithm can reduce 55~70% of the computational time, while maintaining high RD performance.","Title: Factors Influencing Marketing Effectiveness on the Web\nYear: 2001\n\nAbstract: Despite the current development of Internet marketing, understanding the effective use of the Internet still poses problems for academic researchers and marketers Kassaye, 1999. This research attempts to empirically explore some of the critical factors influencing commercial Internet and Web development. The key factors considered for company Internet and Web site development are aspects of technology capacity, the use of different Internet developers, the approaches used to evaluate on-line marketing effectiveness and the marketing executives' knowledge of Internet technology. As a result of a cross-sectional comparative study of 'effective' and 'ineffective' companies, the findings indicate that companies with higher on-line marketing effectiveness tend to possess higher levels of technological capabilities for Internet-based marketing. The results also show that their marketing executives have a better knowledge of technical aspects of Web site development. They tend to be early Internet adopters using a multiple approach to evaluate their on-line marketing efforts. These exploratory results indicate how on-line strategies could be made to be more effective.","Title: On-Line Estimation And Correction Of Voltage Stability Index As Slack Nodes Failure\nYear: 2013\n\nAbstract: Along with the widely application of the Wide-Area Measurement System in power system, voltage instability based on WAMS is becoming all increasingly important worldwide issue. By using the WAMS to collect the measured value of local voltage and current vector directly, we can realize the online estimate and instruction of the voltage stability degree of key node. Use this as a foundation, this paper analyses problems in the phase failure of slack node, puts forward that taking the voltage phase of the node, which has the nearest electrical distance from the slack node, as the reference phase; and according to the least square method based on historical data of WAMS two effective methods to correct and estimate the voltage andcurrent phasor of the key node, can also realize online correction and estimating of the voltage stability of the key node. The simulations show that this method is suitable for the surveillance of online static voltage stability of node and has certain feasibility.","Title: Image Resizing Based on Geometry Preservation with Seam Carving\nYear: 2012\n\nAbstract: When an image or a video is transformed to an aspect ratio deferent from its original size, information lost is inevitable no matter what method is used, thus, how to keep the most attractive contents and minimize the visual distortion during the resizing process is the key issue. To address this problem, this paper proposes an object geometry preservation method based on the seam carving method. We first define a framework that measures the importance of geometry feature in the source material, then a new energy function is presented with object geometry constraint, according to the new energy function, an optimized seam carving method is used to minimize distortion while resizing the source material. The experiment results show that our method is better to transform a variety of source images to a different display size than conventional resizing methods.","Title: Lightweight content-adaptive coding in joint analyzing-encoding framework\nYear: 2008\n\nAbstract: A novel joint analyzing-encoding framework is proposed in this paper. With this framework, the video analysis and the video coding can be integrated together, which can decrease the computational complexity of the video process system due to the obtained shared information. A lightweight content-adaptive video coding scheme can be achieved by using the presented framework for H.264 standard. The side encoding information, including motion vectors (MVs) and sum of absolute differences (SADs), can be used to reduce the computation cost of the moving region analysis. First, the rectangular shape and the displacement information of the moving region in the current encoded frame are obtained by employing a robust binary detection method, which is based on the adaptive threshold and the fast components labeling algorithm. Then, the rectangular shape information of the next frame is achieved by using a simple but effective prediction method, which considers the principle of the temporal motion constraint. Finally, a motion importance mask map (MIMP) is obtained according to the predicted rectangular shape information. Meanwhile, a category of frequency coefficient suppression(FCS) technique in the transform domain is presented to avoid the use of the complex MB-layer rate control method. With MIMP and FCS, a lightweight content-adaptive video coding scheme is realized based on a simple frame-layer rate control method. Experimental results show that the proposed scheme can detect and predict the moving regions fast and improve the objective/subjective visual quality significantly for the moving regions.","Title: Tracking Coverage throughout Epochs with Bounded Uncertainty\nYear: 2011\n\nAbstract: This work addresses the problem of managing the sensor-coverage and organizing the epochs in a manner that balances the trades-offs between the accuracy and energy consumptions during target tracking in Wireless Sensor Networks (WSN). While the typical target tracking approaches are based on movement prediction, we only assume a knowledge of some maximal speed of the target during certain time-intervals. This, in turn, restricts its whereabouts to a disk-bound area throughout such intervals. In such settings, we seek to determine a sensor cover, a subset of all the nodes that need to be awake, which ensures that the target can be detected during the given epoch. Towards this, we propose sensor-cover selection methodologies, Greedy Uncertain Moving Object coverage sensor set selection (GUMO) and PAttern Based coverage sensor set selection (PAB). GUMO is a heuristic maximizing the coverage gain at each step, while PAB is an approach based on optimal deployment pattern of sensor nodes achieving coverage of the disk area bounding the target's whereabouts. We conduct extensive simulations to evaluate the performance of the algorithms, and the results reveal that GUMO and PAB not only provide substantial energy saving due to reduction in the communications involved in selecting tracking participant-nodes and principal(s), while assuring a bounded error on the target's location.","Title: Optimizing the live migration of virtual machine by CPU scheduling\nYear: 2011\n\nAbstract: Live migration has been proposed to reduce the downtime for migrated VMs by pre-copying the generated run-time memory state files from the original host to the migration destination host. However, if the rate for such a dirty memory generation is high, it may take a long time to accomplish live migration because a large amount of data needs to be transferred. In extreme cases when dirty memory generation rate is faster than pre-copy speed, live migration will fail. In this work we address the problem by designing an optimization scheme for live migration, under which according to pre-copy speed, the VCPU working frequency may be reduced so that at a certain phase of the pre-copy the remaining dirty memory can reach a desired small amount. The VM downtime during the migration can be limited. The scheme works for the scenario where the migrated application has a high memory writing speed, or the pre-copy speed is slow, e.g., due to low network bandwidth between the migration parties. The method improves migration liveness at the cost of application performance, and works for those applications for which interruption causes much more serious problems than quality deterioration. Compared to the original live migration, our experiments show that the optimized scheme can reduce up to 88% of application downtime with an acceptable overhead.","Title: Connectivity compression for stripified triangle meshes\nYear: 2007\n\nAbstract: Modern graphics application systems have to render many 3D triangle mesh models, thereby facing problems of memory and bandwidth. A general significant solution is to compress the static 3D triangle mesh model at the preprocessing phase, especially the topological information. This paper presents a new triangle meshes compression algorithm, which encodes connectivity information between vertex chains in the meshes that are already stripified. The proposed algorithm provides a new representation that is guaranteed to encode any stripified meshes in less than 1.67 bits/T, and 1.05 bits/T on average. Furthermore, the proposed algorithm employs a short compression/decompression time. Hence it will satisfy real-time rendering constraints.","Title: Bypassing Holes in Sensor Networks: Load-Balance vs. Latency.\nYear: 2011\n\nAbstract: This work addresses the problem of geographic routing in the presence of holes or voids in wireless sensor networks. We postulate that, once the boundary of the hole has been established, relying on the existing algorithms for bypassing it may cause severe depletion of the energy reserves among the nodes at (or near) that boundary. This, in turn, may soon render some of those nodes useless for any routing (and/or sensing) purposes, thereby effectively enlarging the size of the pre-existing hole. To extend the lifetime of the nodes along the boundary of a given hole, we propose two heuristic approaches which aim at relieving some of the routing load of the boundary nodes. Towards that, our approaches propose that some of the routes that would otherwise need to bypass the hole along the boundary, should instead start to deviate from their original path further from the hole. Our experiments demonstrate that the proposed approaches not only increase the lifetime of the nodes along the boundary of a given hole, but also yield a more uniform depletion of the energy reserves in its vicinity.","Title: Ontology Based Automatic Image Annotation Using Multi-class SVM\nYear: 2013\n\nAbstract: Image annotation is usually formed as a multiclass classification problem. Traditional methods learn the co-occurrence of keywords and images while they ignore the correlation between keywords, which turned out to be one of the reasons causing poor experiment results. In this paper, we propose an automatic image annotation approach by using multiclass SVM with ontology to achieve a higher accuracy. In our paper, we choose semantic dictionary Word Net in which hierarchy defined words are derived from the text ontology to calculate the correlations between keywords. Specifically, we use Bags of Visual Words model to present the image visual feature and apply a mixed kernel in multiclass SVM. Finally, we combine the probability outputs to get the final results. Compared to other state-of-the-art multiclass classification methods, our approach tested in typical Corel dataset maintain a high level of accuracy in classification.","Title: Analysis of Spectral Efficiency and Management of Cross-Tier Interference in Femtocell Network\nYear: 2013\n\nAbstract: Femtocell is on the way of being extensively deployed in households to provide better indoor coverage and higher user capacity. However, as the coverage of femtocell is overlapped with that of conventional macrocell, the cross-tier interference may result in a considerable degradation of system performance in terms of spectral efficiency. This paper focuses on the improvement of cell spectral efficiency in two-tier network. We first derive the explicit expressions of cell spectral efficiency and average spectral efficiency of single user in each tier. Some remarks and observations are provided after analyzing numerical results of the expressions. Then based on the theoretical analysis, we propose a dynamic cross-tier interference coordination (D-CTIC) scheme. D-CTIC can provide high cell spectral efficiency by maximizing the number of coexistent femtocell base stations (FBSs) with macrocell base station (MBS) while still satisfying the QoS requirement of macrocell user (MUE) by restricting cross-tier interference under an acceptable level. Finally, simulation results verify the theoretical analysis and show that D-CTIC can enhance cell spectral efficiency significantly.","Title: Research on supply chain versus supply chain competition with product quality and price dependent demand\nYear: 2012\n\nAbstract: This paper firstly studies the quality and pricing competition between two supply chains providing two kinds of substitutable products with product quality and price dependent demand for an identical market, where each supply chain (Simply denoted as SC) consists of one manufacturer and one retailer. EPEC (Equilibrium Problems with Equilibrium Constrains) model, MPEC (Mathematical Programs with Equilibrium Constrains) model and Nash equilibrium model are set up by using game theory and equilibrium analysis method, which respectively characterize the competition equilibrium between two centralized SCs, two decentralized SCs, one centralized SC and one decentralized SC. Secondly, a profit-sharing contract is put forward to coordinate one decentralized SC to be centralized SC under SC vs. SC competition. Finally, numerical examples show the correctness of the models and the validity of the contract. It shows that coordination is a dominant strategy, and consumer are the beneficiaries who can obtain more consumer welfare since SC coordination leads lower retail prices and more supply quantities.","Title: Trajectory Data Reduction In Wireless Sensor Networks\nYear: 2010\n\nAbstract: This work addresses the problem of balancing the trade-off between the energy cost due to communication and the accuracy of the tracking-based trajectories' detection and representation in Wireless Sensor Networks (WSNs) settings. We consider some of the approaches used by the Moving Objects Databases (MOD) and Computational Geometry (CG) communities, and we demonstrate that with appropriate adaptation, they can yield significant benefits in terms of energy savings and, consequently, lifetime of a given WSN. Towards that, we developed distributed variations of three approaches for spatio-temporal data reduction - two heuristics (Dead-Reckoning and the Douglas-Peuker algorithm), and a variant of a CG-based optimal algorithm for polyline reduction. In addition, we examine different policies for managing the buffer used by the individual tracking nodes for storing the partial trajectory data. Lastly, we investigated the potential benefits of combining the different data-reduction approaches into \"hybrid\" ones during tracking of a particular object's trajectory. Our experiments demonstrate that the proposed methodologies can significantly reduce the network-wide energy expenses due to communication and increase the network lifetime.","Title: Deflection-Aware Tracking-Principal Selection in Active Wireless Sensor Networks.\nYear: 2012\n\nAbstract: This paper addresses the problem of energy efficiency balanced with tracking accuracy in wireless sensor networks (WSNs). Specifically, we focus on the issues related to selecting tracking principals, i.e., the nodes with two special tasks: 1) coordinating the activities among the sensors that are detecting the tracked object's locations in time and 2) selecting a node to which the tasks of coordination and data fusion will be handed off when the tracked object exits the sensing area of the current principal. Extending the existing results that based the respective principal selection algorithms on the assumption that the target's trajectory is approximated with straight line segments, we consider more general settings of (possibly) continuous changes of the direction of the moving target. We developed an approach based on particle filters to estimate the target's angular deflection at the time of a handoff, and we considered the tradeoffs between the expensive in-node computations incurred by the particle filters and the imprecision tolerance when selecting subsequent tracking principals. Our experiments demonstrate that the proposed approach yields significant savings in the number of handoffs and the number of unsuccessful transfers in comparison with previous approaches. © 1967-2012 IEEE.","Title: Application of 4-point subdivision to generate in-between frames in skeletal animation\nYear: 2006\n\nAbstract: Regarding the modeling aspects of computer animation, the skeletal animation is a newfangled modeling technology to assist in single-mesh model animation. There are two aspects of advancement proposed in this paper. First, we construct a novel vertical data structure (Modified Body-Tree) to describe the skeletal models in animation. Second, instead of normal methods such as linear interpolation and higher-order spline interpolation to generate in-between frame, we proposes an adaptive and high-performance algorithm based on 4-Point subdivision scheme to generate in-between frame in the skeletal animation. By this advanced algorithm, a smoother skeletal animation with blander vision effect is achieved.","Title: Selecting tracking principals with epoch awareness\nYear: 2010\n\nAbstract: This work addresses the problem of principal node selection during the tracking process in Wireless Sensor Networks (WSNs). In a typical tracking scenario, the location of a mobile unit is determined via collaborative trilateration by the nodes that have the tracked object within their sensing range. One of the participants in the trilateraion---the tracking principal---is in charge of transmitting the location and time information to a designated sink. However, as the moving object changes its location, a new principal needs to be determined and handed off the task of the subsequent sensing, trilateration and transmission to the sink. We observe that in many WSN applications in which sensing/sampling needs to be combined with multihop transmission and, possibly, in-network aggregation, the typical processing is organized in synchronized intervals, called epochs. We postulate that taking the semantics of the epoch into consideration is important when selecting tracking principals and we present efficient algorithmic solutions towards this goal. Our experiments demonstrate that the proposed approach can yield significant reduction in the number of hand-offs between consecutive tracking principals, when compared to previous works.","Title: Predicting audience gender in online content-sharing social networks.\nYear: 2013\n\nAbstract: Understanding the behavior and characteristics of web users is valuable when improving information dissemination, designing recommendation systems, and so on. In this work, we explore various methods of predicting the ratio of male viewers to female viewers onYouTube. First, we propose and examine two hypotheses relating to audience consistency and topic consistency. The former means that videos made by the same authors tend to have similar male-to-female audience ratios, whereas the latter means that videos with similar topics tend to have similar audience gender ratios. To predict the audience gender ratio before video publication, two features based on these two hypotheses and other features are used in multiple linear regression (MLR) and support vector regression (SVR). We find that these two features are the key indicators of audience gender, whereas other features, such as gender of the user and duration of the video, have limited relationships. Second, another method is explored to predict the audience gender ratio. Specifically, we use the early comments collected after video publication to predict the ratio via simple linear regression (SLR). The experiments indicate that this model can achieve better performance by using a few early comments. We also observe that the correlation between the number of early comments (cost) and the predictive accuracy (gain) follows the law of diminishing marginal utility. We build the functions of these elements via curve fitting to find the appropriate number of early comments (approximately 250) that can achieve maximum gain at minimum cost.","Title: Method for fundamental matrix estimation combined with feature lines\nYear: 2015\n\nAbstract: Fundamental matrix estimation has been studied extensively in the area of computer vision and previously proposed techniques include those that only use feature points. In this study, we propose a new technique for calculating the fundamental matrix combined with feature lines, which is based on the epipolar geometry of horizontal and vertical feature lines. First, a method for parameterizing the fundamental matrix is introduced, where the camera orientation elements and relative orientation elements are used as the parameters of the fundamental matrix, and the equivalent relationships are deduced based on the horizontal and vertical feature lines. Next, the feature lines are used as the interior points by the RANSAC algorithm to search for the optimal feature point subset, before determining the weight of each factor using the M-estimators algorithm and building a unified adjustment model to estimate the fundamental matrix. The experimental results obtained using simulated images and real images demonstrate that the proposed approach is feasible in practice and it can greatly reduce the dependency on feature points in the traditional method, while the introduction of feature lines can improve the accuracy and stability of the results to some extent.","Title: An adaptive neural fuzzy network clothing comfort evaluation model and application in digital home\nYear: 2014\n\nAbstract: With the development of digital TV, especially 3D technologies, some applications in the digital home industry have been reported to meet and even exceed customer expectation in the market place for enterprise. In order to evaluate the clothing comfort performance in the digital e-commerce service, the clothing comfort model is very important. Considered the physical, physiological and psychological factors, a theoretical clothing comfort evaluation model is presented based on the adaptive fuzzy neural network in this paper. According to the characters of clothing comfort, Fuzzy Neural Networks (FNN) can provide a very human machine knowledge representation scheme friendly for acquiring, representing and using the knowledge of the domain expert. This is a significant advantage for clothing comfort evaluation where the exact system transfer functions cannot be well modeled and adequate training data sets are not available. The experiment results shown that there has the same prediction trend about the experiment result and simulation result. This clothing comfort evaluation model is used as a component in the smart clothing function user experience system.","Title: Dynamic cross-tier interference management in heterogeneous network\nYear: 2013\n\nAbstract: As conventional single-layered network cannot satisfy the increasing demand in high-speed indoor data service, femtocell has been introduced to provide higher network capacity and better user experience. However, the downlink transmit signal from femtocell base station (FBS) may result in severe cross-tier interference to macrocell users (MUE). To address this problem, we propose a dynamic femtocell exclusion mechanism to alleviate the downlink cross-tier interference for MUE. The radius of the femtocell exclusion area, which is defined as reuse distance, is analyzed while taking account of the target outage probability and random position of the interfering FBSs. We derive the closed-form expression of the outage probability as a function of reuse distance. This expression provides a simple method to plan the exclusion area around the victim MUE. In addition, we introduce reuse table to avoid unpredictable interference caused by random appeared active FBS. Simulation results verify our theoretical analysis and show that the proposed mechanism can effectively alleviate the downlink cross-tier interference and improve the user capacity of the network.","Title: Spatio-temporal correlation-based fast coding unit depth decision for high efficiency video coding\nYear: 2013\n\nAbstract: The exhaustive block partition search process in high efficiency video coding (HEVC) imposes a very high computational complexity on test module of HEVC encoder (HM). A fast coding unit (CU) depth algorithm using the spatio-temporal correlation of the depth information to fasten the search process is proposed. The depth of the coding tree unit (CTU) is predicted first by using the depth information of the spatio-temporal neighbor CTUs. Then, the depth information of the adjacent CU is incorporated to skip some specific depths when encoding the sub-CTU. As compared with the original HM encoder, experimental results show that the proposed algorithm can save more than 20% encoding time on average for intra-only, low-delay, low-delay P slices, and random access cases with almost the same rate-distortion performance. (C) 2013 SPIE and IS&T","Title: A nonlinear smoother for target tracking in asynchronous wireless sensor networks\nYear: 2015\n\nAbstract: Generally, multiple sensors are deployed to track a target synchronously in wireless sensor networks. However, asynchronous measurements exist intrinsically in multi-rate multi-sensor systems. Asynchronous measurements may also emerge in acoustic sensor networks, owing to the low propagation speed of acoustic signals. In order to handle the target tracking problem with asynchronous measurements, a nonlinear smoothing algorithm based on the fixed-point smoother and the square-root cubature Kalman filter is derived and applied in asynchronous wireless sensor networks for the first time. The estimation precision of the states increases along with the smoothing process, and a sensor can always obtain the optimal estimate of a state before its own next measurement by using the proposed algorithm. The numerical simulations demonstrate that, thanks to the smoothing effect of the fixed-point smoother, the proposed algorithm can obtain not only the remarkable position estimation results of the target, but also even better velocity estimation results. In addition, the proposed algorithm can obtain much more states' estimates than benchmark synchronous target-tracking algorithms, under the same condition of measurement count and communication cost.","Title: Retiling scheme: a novel approach of direct anisotropic quad-dominant remeshing.\nYear: 2016\n\nAbstract: Remeshing has been an active research topic in Digital Geometry Processing. In this paper, a novel approach of direct anisotropic quad-dominant remeshing is proposed. We apply the retiling method to the particular problem of quad-dominant remeshing. Compared with other methods, this method can simply partition the surface of an original triangular mesh into connected quads with the mesh edges aligning to the principal directions. The first step in this method is to estimate and smooth the curvature tensor field of the surface at the vertices, and then the quad-dominant mesh is obtained by retiling the quad surface so that quadrilateral edges are parallel to the local principal curvature directions. In addition, to preserve the sharp feature information during remeshing processes, the feature lines can be extracted using mesh segmentation method, and the intersections between the feature lines and the orthogonal planes can be found during the process of retiling. A feature fusion process is presented to join the feature edges and feature points into the quad-dominant mesh. The experiment results show that this new remeshing method is simple and easy to implement. The resolution of the quadrilateral mesh can be controlled during the remeshing. It is applicable to arbitrary genus meshes and can generate high-quality quad-dominant mesh.","Title: Learning-Based and Data-Driven TCP Design for Memory-Constrained IoT\nYear: 2016\n\nAbstract: Advances in wireless technology have resulted in pervasive deployment of devices of a high variability in form factors, memory and computational ability. The need for maintaining continuous connections that deliver data with high reliability necessitate re-thinking of conventional design of the transport layer protocol. This paper investigates the use of Q-learning in TCP cwnd adaptation during the congestion avoidance state, wherein the classical alternation of the window is replaced, thereby allowing the protocol to immediately respond to previously seen network conditions. Furthermore, it demonstrates how memory plays a critical role in building the exploration space, and proposes ways to reduce this overhead through function approximation. The superior performance of the learning-based approach over TCP New Reno is demonstrated through a comprehensive simulation study, revealing 33.8% and 12.1% improvement in throughput and delay, respectively, for the evaluated topologies. We also show how function approximation can be used to dramatically reduce the memory requirements of a learning-based protocol while maintaining the same throughput and delay.","Title: Efficient multi-account detection on UGC sites\nYear: 2016\n\nAbstract: This work presents a novel writing style-based approach to detect multi-account users on User-Generated Content (UGC) sites. Unlike existing works which emphasize feasibility and privacy leakage, we focus on precise writing style-based multi-account detection. Specifically, we leverage a one-class classification-based approach to detect multi-account behaviors, in which a mutual similarity measurement is defined to increase detection precision. In addition to traditional features used in writing style detection, we also extract bigrams, trigrams, part-of-speech, and grammatical relations. We evaluate our methodology based on datasets crawled from 3 popular OSNs (i.e., Twitter, Facebook, and Google+). Experimental results demonstrate that compared with the most recent achievements, our method not only improves the average detection precision to almost 90%, but also increases both recall and F-measure to 90% and even better.","Title: Genome-wide association analysis of secondary imaging phenotypes from the Alzheimer's disease neuroimaging initiative study.\nYear: 2017\n\nAbstract: The aim of this paper is to systematically evaluate a biased sampling issue associated with genome-wide association analysis (GWAS) of imaging phenotypes for most imaging genetic studies, including the Alzheimer's Disease Neuroimaging Initiative (ADNI). Specifically, the original sampling scheme of these imaging genetic studies is primarily the retrospective case-control design, whereas most existing statistical analyses of these studies ignore such sampling scheme by directly correlating imaging phenotypes (called the secondary traits) with genotype. Although it has been well documented in genetic epidemiology that ignoring the case-control sampling scheme can produce highly biased estimates, and subsequently lead to misleading results and suspicious associations, such findings are not well documented in imaging genetics. We use extensive simulations and a large-scale imaging genetic data analysis of the Alzheimer's Disease Neuroimaging Initiative (ADNI) data to evaluate the effects of the case-control sampling scheme on GWAS results based on some standard statistical methods, such as linear regression methods, while comparing it with several advanced statistical methods that appropriately adjust for the case-control sampling scheme.","Title: ActiveRec: A Novel Context-Sensitive Ranking Method for Active Movie Recommendation\nYear: 2016\n\nAbstract: This paper presents a novel context-sensitive ranking algorithm, called ActiveRec, for providing flexible movie recommendations. Typically, ActiveRec can recommend movies to a user according to a specific movie type, or to a group of users satisfying their common interests. Firstly, ActiveRec constructs a multipartite graph where the nodes represent users, movies, and joint information, respectively. And then, a biased random-walk is performed to obtain the similarity between the request vector and every node on the graph. Based on the similarities, ActiveRec sorts out all movies that meet the user requirements and notify the user of a Top-N list. Additionally, a time-decay model following the Ebbinghaus forgetting curve is introduced to imitate the decay process of the importance of users' feedbacks when computing the edges' weights in the graph. Extensive experiments are performed on a real dataset to evaluate the performance. The results demonstrate that ActiveRec not only satisfies the requirements of flexible recommendations, but also achieves higher performance compared to the existing works.","Title: Shaping LDLC Lattices Using Convolutional Code Lattices\nYear: 2017\n\nAbstract: In this letter, we show how to construct low-density lattice code (LDLC) lattices shaped using convolutional code lattices. First, we give an explicit method to find the generator matrices of convolutional code lattices. The shaping gain of convolutional code lattices based on rate 1/2 convolutional codes for short block length is found by evaluating the normalized second moment; a shaping gain as high as 1.24 dB for dimension $n=200$ was found. Then, nested LDLC lattices are constructed. We design LDLC lattices that satisfy conditions necessary for forming nested lattice codes, and give a specific example. For an $n=36$ dimensional lattice, a lattice code based on LDLC lattices, shaped using convolutional code lattices, has a shaping gain of 0.87 dB, over hypercube shaping.","Title: Efficient detection of motion-trend predicates in wireless sensor networks.\nYear: 2017\n\nAbstract: This work addresses the problem of efficient distributed detection of predicates capturing the motion trends of mobile objects evaluated with respect to a (boundary of a) polygonal region, in the settings in which the (location, time) data is obtained via tracking in Wireless Sensor Networks (WSN). Specifically, we discuss in-network distributed algorithms for detecting two motion-trend predicates: Continuously Moving Towards and Persistently Moving Towards: first for a single object, and then the corresponding variants for multiple objects. We also present methodologies which consider the energy vs. latency trade-offs when multiple tracked objects are being considered for validating the monitored predicates. Our experiments demonstrate that our proposed technique yield substantial energy savings when compared to the nave centralized and cluster-based approaches in which the raw (location, time) data is transmitted to a dedicated sink where the predicates are being evaluated.","Title: Bypassing holes in sensor networks: Load-balance vs. latency.\nYear: 2017\n\nAbstract: This work addresses problems that arise when geographic routing is used in the presence of holes in wireless sensor networks. We postulate that relying on the existing algorithms for bypassing a coverage hole may cause more severe depletion of the energy reserves among the nodes at (or near) that hole’s boundary. This, in turn, will render some of those nodes useless for any routing (and/or sensing) purposes, thereby effectively enlarging the size of existing hole and inducing longer communication delays for certain (source, sink) pairs. We propose heuristics that address these complementary problems: (1) relieving some of the routing-load for the nodes around the boundary of a given hole, for the purpose of extending their lifetime; and (2) reducing the latency of the packets-delivery by using routes that are within certain bounds from the route based on the shortest-path. Our approaches are based on the idea that some of the packets that would (otherwise) need to be routed along the boundary of a given hole, should instead start to deviate from their original path further away from that hole. To investigate the potential benefits, we introduce approximations of the hole’s boundary with a rectangle, a circle and an ellipse, respectively. We derive the bounds on reducing the routing latency for these three approximations. Our experiments demonstrate that the proposed approaches not only increase the lifetime of the nodes along the boundary of a given hole and yield a more uniform depletion of the energy reserves in its vicinity, but also reduce the communication latency, compared to the traditional face routing.","Title: Dynamic Generalization Kanerva Coding in Reinforcement Learning for TCP Congestion Control Design.\nYear: 2017\n\nAbstract: Traditional reinforcement learning (RL) techniques often encounter limitations when solving large or continuous state-action spaces. Training times needed to explore the very large space are impractically long, and it can be difficult to generalize learned knowledge. A compact representation of the state space is usually generated to solve both problems. However, simple state abstraction often cannot achieve the desired learning quality, while expert state representations usually involve costly hand-crafted strategies. We propose a new technique, generalization-based Kanerva coding, that automatically generates and optimizes state abstractions for learning. When applied to adapting the congestion window of the highly complex TCP congestion control protocol, a standard Internet protocol, this technique outperforms the current standard-TCP New Reno by 59.5% in throughput and 6.5% in delay. Our technique also achieves a 35.2% improvement in throughput over the best previously proposed Kanerva coding technique when applied in the same context.","Title: Illumination insensitive efficient second-order minimization for planar object tracking.\nYear: 2017\n\nAbstract: Tracking for planar objects is an important issue to vision-based robotic applications. In direct visual tracking (DVT) methods, the similarity between two images is often measured through the sum of squared differences (SSD) especially with the efficient second-order minimization (ESM) due to its simplicity and efficiency. However, SSD-based ESM is not robust to illumination changes since it is usually built upon the brightness constancy assumption. Contrast to image brightness, gradient orientations (GO) are invariant to both linear and non-linear illumination changes as verified in practice. Based on GO, we propose an illumination insensitive ESM method for planar object tracking in this paper. In order to introduce GO into the ESM, we generalized the original ESM formulas for multi-dimensional features. In addition, a denoising method based on the Perona-Malik function and a mask image were suggested to improve GOu0027s robustness against image noise and low texture. Our experimental results on dataset for planar objects with illumination changes and a benchmark dataset confirm the proposed method is robust to illumination variations and capable to deal with the general tracking challenges.","Title: The $\\ell_\\infty$ Perturbation of HOSVD and Low Rank Tensor Denoising.\nYear: 2017\n\nAbstract: The higher order singular value decomposition (HOSVD) of tensors is a generalization of matrix SVD. The perturbation analysis of HOSVD under random noise is more delicate than its matrix counterpart. Recent progress has been made in Richard and Montanari (2014), Zhang and Xia (2017) and Liu et al. (2017) demonstrating that minimax optimal singular spaces estimation and low rank tensor recovery in $ell_2$-norm can be obtained through polynomial time algorithms. In this paper, we analyze the HOSVD perturbation under Gaussian noise based on a second order method, which leads to an estimator of singular vectors with sharp bound in $ell_infty$-norm. A low rank tensor denoising estimator is then proposed which achieves a fast convergence rate characterizing the entry-wise deviations. The advantages of these $ell_infty$-norm bounds are displayed in applications including high dimensional clustering and sub-tensor localizations.","Title: Identifying Human Mobility via Trajectory Embeddings.\nYear: 2017\n\nAbstract: Understanding human trajectory patterns is an important task in many location based social networks (LBSNs) applications, such as personalized recommendation and preference-based route planning. Most of the existing methods classify a trajectory (or its segments) based on spatio-temporal values and activities, into some predefined categories, e.g., walking or jogging. We tackle a novel trajectory classification problem: we identify and link trajectories to users who generate them in the LBSNs, a problem called Trajectory-User Linking (TUL). Solving the TUL problem is not a trivial task because: (1) the number of the classes (i.e., users) is much larger than the number of motion patterns in the common trajectory classification problems; and (2) the location based trajectory data, especially the check-ins, are often extremely sparse. To address these challenges, a Recurrent Neural Networks (RNN) based semi-supervised learning model, called TULER (TUL via Embedding and RNN) is proposed, which exploits the spatio-temporal data to capture the underlying semantics of user mobility patterns. Experiments conducted on real-world datasets demonstrate that TULER achieves better accuracy than the existing methods.","Title: Association Rules Mining with Quantum Computing and Quantum Storage\nYear: 2017\n\nAbstract: The rapid development of big data puts forward higher requirements on computational efficiency and storage capacity. But the traditional mining algorithms based on classical computing were unable to satisfy the demand of data analysis and computing. Because of quantum systems unique ability of hyper parallel computation and hyper acceleration, the large-scale computing and data storage can be solve well. Although the development of quantum computer has not yet achieved a qualitative leap, quantum computing in big data application has achieved lots of theoretical achievements. In this paper, we make quantum data mining as a starting point. Since we have no sufficient space to store candidate sets of association rules and have low computation ability in the processing of association rules, we propose a novel quantum method of data storage and retrieval for association rules mining based on Boolean matrix, we propose the algorithm called Q-Eclat can accelerate the computation of candidate sets support. According to our analysis based on open data source, the proposed method outperforms the classical Eclat algorithm in terms of storage capacity and computing ability.","Title: A Data-Driven Approach for Sketch-Based 3D Shape Retrieval via Similar Drawing-Style Recommendation.\nYear: 2017\n\nAbstract: Sketching is a simple and natural way of expression and communication for humans. For this reason, it gains increasing popularity in human computer interaction, with the emergence of multitouch tablets and styluses. In recent years, sketch-based interactive methods are widely used in many retrieval systems. In particular, a variety of sketch-based 3D model retrieval works have been presented. However, almost all of these works focus on directly matching sketches with the projection views of 3D models, and they suffer from the large differences between the sketch drawing and the views of 3D models, leading to unsatisfying retrieval results. Therefore, in this paper, during the matching procedure in the retrieval, we propose to match the sketch with each 3D model from historical users instead of projection views. Yet since the sketches between the current user and the historical users can have big difference, we also aim to handle users' personalized deviations and differences. To this end, we leverage recommendation algorithms to estimate the drawing style characteristic similarity between the current user and historical users. Experimental results on the Large Scale Sketch Track Benchmark(SHREC14LSSTB) demonstrate that our method outperforms several state-of-the-art methods.","Title: Towards Fast Flow Convergence in Cognitive Radio Cellular Networks.\nYear: 2017\n\nAbstract: Cognitive radio (CR) is an enabling technology that allows opportunistic use of under-utilized licensed spectrum allocated to primary users (PUs). However, the frequent channel sensing and switching interferes with the transport layer functions, leading to slow flow convergence during active transmissions by the CR. In this paper, we propose TCP C-2, a method that greatly improves the flow responsiveness to abrupt variation of underlying layer spectrum availability in cellular CR architectures. The key idea of C-2 is to allow the sender to estimate the current bottleneck link bandwidth and network load by observing variance in the throughput and round trip time. Following this, fast congestion window scaling allows the flow to converge quickly to the optimal sending rate. Analytic derivations and packet-based simulation results show the increased resiliency of our approach over classical end-to-end TCP protocols in the presence of intermittent spectrum sensing and disruptions caused by PU arrival. Additionally, we show that C-2 enforces fairness among flows, and also coexists well with classical TCP flavors.","Title: TPCNN: Two-Phase Patch-Based Convolutional Neural Network for Automatic Brain Tumor Segmentation and Survival Prediction.\nYear: 2017\n\nAbstract: The aim of this paper is to integrate some advanced statistical methods with modern deep learning methods for tumor segmentation and survival time prediction in the BraTS 2017 challenge. The goals of the BraTS 2017 challenge are to utilize multi-institutional pre-operative MRI scans to segment out different tumor subregions and then to use tumor information to predict patient's overall survival. We build a twophase patch-based convolutional neural network (TPCNN) model to classify all the pixels in the brain and further refine the segmentation results by using XGBoost and a post-processing procedure. The segmentation results are then used to extract various informative radiomic features for prediction of the survival time by using the XGBoost method.","Title: Torque sensorless decentralized neuro-optimal control for modular and reconfigurable robots with uncertain environments.\nYear: 2018\n\nAbstract: A technical challenge of addressing the decentralized optimal control problem for modular and reconfigurable robots (MRRs) during environmental contacts is associated with optimal compensation of the uncertain contact force without using force/torque sensors. In this paper, a decentralized control approach is presented for torque sensorless MRRs in contact with uncertain environment via an adaptive dynamic programming (ADP)-based neuro-optimal compensation strategy. The dynamic model of the MRRs is formulated based on a novel joint torque estimation method, which is deployed for each joint model, and the joint dynamic information is utilized effectively to design the feedback controllers, thus making the decentralized optimal control problem of the environmental contacted MRR systems be formulated as an optimal compensation issue of model uncertainty. By using the ADP method, a local online policy iteration algorithm is employed to solve the Hamilton–Jacobi–Bellman (HJB) equation with a modified cost function, which is approximated by constructing a critic neural network, and then the approximate optimal control policy can be derived. The asymptotic stability of the closed-loop MRR system is proved by using the Lyapunov theory. At last, simulations and experiments are performed to verify the effectiveness of the proposed method.","Title: Automatic Registration of Images With Inconsistent Content Through Line-Support Region Segmentation and Geometrical Outlier Removal.\nYear: 2018\n\nAbstract: The implementation of automatic image registration is still difficult in various applications. In this paper, an automatic image registration approach through line-support region segmentation and geometrical outlier removal is proposed. This new approach is designed to address the problems associated with the registration of images with affine deformations and inconsistent content, such as remote ...","Title: A Label-Fusion-Aided Convolutional Neural Network For Isointense Infant Brain Tissue Segmentation\nYear: 2018\n\nAbstract: The extremely low tissue contrast in white matter during an infant's isointense stage (6-8 months) of brain development presents major difficulty when segmenting brain image regions for analysis. We sought to develop a label-fusion-aided deep-learning approach for automatically segmenting isointense infant brain images into white matter, gray matter and cerebrospinal fluid using T-1- and T-2-weighted magnetic resonance images. A key idea of our approach is to apply the fully convolutional neural network (FCNN) to individual brain regions determined by a traditional registration-based segmentation method instead of training a single model for the whole brain. This provides more refined segmentation results by capturing more region-specific features. We show that this method outperforms traditional joint label fusion and FCNN-only methods in terms of Dice coefficients using the dataset from iSEG MICCAI Grand Challenge 2017.","Title: Trajectory-User Linking via Variational AutoEncoder.\nYear: 2018\n\nAbstract: Trajectory-User Linking (TUL) is an essential task in Geo-tagged social media (GTSM) applications, enabling personalized Point of Interest (POI) recommendation and activity identification. Existing works on mining mobility patterns often model trajectories using Markov Chains (MC) or recurrent neural networks (RNN) - either assuming independence between non-adjacent locations or following a shallow generation process. However, most of them ignore the fact that human trajectories are often sparse, high-dimensional and may contain embedded hierarchical structures. We tackle the TUL problem with a semi-supervised learning framework, called TULVAE (TUL via Variational AutoEncoder), which learns the human mobility in a neural generative architecture with stochastic latent variables that span hidden states in RNN. TULVAE alleviates the data sparsity problem by leveraging large-scale unlabeled data and represents the hierarchical and structural semantics of trajectories with high-dimensional latent variables. Our experiments demonstrate that TULVAE improves efficiency and linking performance in real GTSM datasets, in comparison to existing methods.","Title: Automatically Detecting the Scopes of Source Code Comments.\nYear: 2018\n\nAbstract: •This work proposes the first method to detect the scopes of block/line comments•The detection of comment scopes can be modeled as a binary classification problem•We propose discriminative features in code and comments to characterize the scopes of comments.•We apply our method to two existing approaches in software engineering tasks and improve their performance.","Title: Automatic Detection of Outdated Comments During Code Changes\nYear: 2018\n\nAbstract: Comments are used as standard practice in software development to increase the readability of code and to express programmers' intentions in a more explicit manner. Nevertheless, keeping comments up-to-date is often neglected for programmers. In this paper, we proposed a machine learning based method for detecting the comments that should be changed during code changes. We utilized 64 features, taking the code before and after changes, comments and the relationship between the code and comments into account. Experimental results show that 74.6% of outdated comments can be detected using our method, and 77.2% of our detected outdated comments are real comments which require to be updated. In addition, the experimental results indicate that our model can help developers to discover outdated comments in historical versions of existing projects.","Title: Identifying Brain Networks of Multiple Time Scales via Deep Recurrent Neural Network.\nYear: 2018\n\nAbstract: For decades, task-based functional magnetic resonance imaging (tfMRI) has been a powerful noninvasive tool to explore the organizational architecture of human brain function. Researchers have developed a variety of brain network analysis methods for tfMRI data, including the general linear model (GLM), independent component analysis (ICA) and sparse representation methods. However, these shallow models are limited in faithful reconstruction and modeling of the hierarchical and temporal structures of brain networks, as demonstrated in more and more studies. Recently, recurrent neural networks (RNNs) exhibit great ability of modeling hierarchical and temporal dependency features in the machine learning field, which might be suitable for tfMRI data modeling. To explore such possible advantages of RNNs for tfMRI data, we propose a novel framework of deep recurrent neural network (DRNN) to model the functional brain networks for tfMRI data. Experimental results on the motor task tfMRI data of Human Connectome Project 900 subjects data release demonstrated that the proposed DRNN can not only faithfully reconstruct functional brain networks, but also identify more meaningful brain networks with multiple time scales which are overlooked by traditional shallow models. In general, this work provides an effective and powerful approach to identifying functional brain networks of multiple time scales from tfMRI data.","Title: vec2Link: Unifying Heterogeneous Data for Social Link Prediction.\nYear: 2018\n\nAbstract: Recent advances in network representation learning have enabled significant improvements in the link prediction task, which is at the core of many downstream applications. As an increasing amount of mobility data becoming available due to the development of location technologies, we argue that this resourceful user mobility data can be used to improve link prediction performance. In this paper, we propose a novel link prediction framework that utilizes user offline check-in behavior combined with user online social relations. We model user offline location preference via probabilistic factor model and represent user social relations using neural network embedding. Furthermore, we employ locality-sensitive hashing to project the aggregated user representation into a binary matrix, which not only preserves the data structure but also speeds up the followed convolutional network learning. By comparing with several baseline methods that solely rely on social network or mobility data, we show that our unified approach significantly improves the performance.","Title: DeepLink: A Deep Learning Approach for User Identity Linkage.\nYear: 2018\n\nAbstract: The typical aim of User Identity Linkage (UIL) is to detect when users from across different social platforms are actually one and the same individual. Existing efforts to address this problem of practical relevance span from user-profile-based, through user-generated-content-based, user-behavior-based approaches to supervised or unsupervised learning frameworks, to subspace learning-based models. Most of them often require extraction of relevant features (e.g., profile, location, biography, networks, behavior, etc.) to model the user consistently across different social networks. However, these features are mainly derived based on prior knowledge and may vary for different platforms and applications. Inspired by the recent successes of deep learning in different tasks, especially in automatic feature extraction and representation, we propose a deep neural network based algorithm for UIL, called DeepLink. It is a novel end-to-end approach in a semi-supervised learning manner, without involving any hand-crafting features. Specifically, DeepLink samples the networks and learns to encode network nodes into vector representation to capture local and global network structures which, in turn, can be used to align anchor nodes through deep neural networks. A dual learning based paradigm is exploited to learn how to transfer knowledge and update the linkage using the policy gradient method. Experiments conducted on several public datasets show that DeepLink outperforms the state-of-the-art methods in terms of both linking precision and identity-match ranking.","Title: Making the Right Connections: Multi-AP Association and Flow Control in 60GHz Band.\nYear: 2018\n\nAbstract: Emerging network architectures in 60GHz millimeter wave bands will likely use dense deployment of access points (APs) given the high attenuation and frequent line-of-sight related outages. We show in this paper that naively connecting to any available AP, or even multiple APs, may not fully realize the promise of efficiently utilizing the extremely large bandwidths available in this band. This paper holistically addresses these problems through the Multi-AP Association Protocol (MAP) that: (i) indicates ideal durations for beam-searching at the physical/link layers of the protocol stack that will result in minimal interruptions to user-traffic, (ii) devises a Multi-AP association framework based on multipath TCP, which increases the network robustness by allowing immediate redirection of traffic to alternative APs whenever an existing connection is interrupted, and (iii) designs an exploration-exploitation aware flow scheduling algorithm that dynamically activates the sub flows to optimize transport layer performance. MAP is a lightweight, client side system that needs zero modifications to existing protocol stack, though it interacts with the latter to opportunistically trigger standards-defined functions. The paper also presents convergence analysis of throughput, experimental validation on a 60GHz network testbed, and trace-driven simulation studies that shows MAP achieving 5-7x reduction in re-buffering rate in HI) video streaming, rapid convergence to the best possible AP, and fair allocation of resources among clients.","Title: Implicit Dual-domain Convolutional Network for Robust Color Image Compression Artifact Reduction.\nYear: 2018\n\nAbstract: Several dual-domain convolutional neural network-based methods show outstanding performance in reducing image compression artifacts. However, they suffer from handling color images because the compression processes for gray-scale and color images are completely different. Moreover, these methods train a specific model for each compression quality and require multiple models to achieve different compression qualities. To address these problems, we proposed an implicit dual-domain convolutional network (IDCN) with the pixel position labeling map and the quantization tables as inputs. Specifically, we proposed an extractor-corrector framework-based dual-domain correction unit (DRU) as the basic component to formulate the IDCN. A dense block was introduced to improve the performance of extractor in DRU. The implicit dual-domain translation allows the IDCN to handle color images with the discrete cosine transform (DCT)-domain priors. A flexible version of IDCN (IDCN-f) was developed to handle a wide range of compression qualities. Experiments for both objective and subjective evaluations on benchmark datasets show that IDCN is superior to the state-of-the-art methods and IDCN-f exhibits excellent abilities to handle a wide range of compression qualities with little performance sacrifice and demonstrates great potential for practical applications.","Title: Trajectory-based social circle inference.\nYear: 2018\n\nAbstract: Learning explicit and implicit patterns in human trajectories plays an important role in many Location-Based Social Networks (LBSNs) applications, such as trajectory classification (e.g., walking, driving, etc.), trajectory-user linking, friend recommendation, etc. A particular problem that has attracted much attention recently - and is the focus of our work - is the Trajectory-based Social Circle Inference (TSCI), aiming at inferring user social circles (mainly social friendship) based on motion trajectories and without any explicit social networked information. Existing approaches addressing TSCI lack satisfactory results due to the challenges related to data sparsity, accessibility and model efficiency. Motivated by the recent success of machine learning in trajectory mining, in this paper we formulate TSCI as a novel multi-label classification problem and develop a Recurrent Neural Network (RNN)-based framework called DeepTSCI to use human mobility patterns for inferring corresponding social circles. We propose three methods to learn the latent representations of trajectories, based on: (1) bidirectional Long Short-Term Memory (LSTM); (2) Autoencoder; and (3) Variational autoencoder. Experiments conducted on real-world datasets demonstrate that our proposed methods perform well and achieve significant improvement in terms of macro-R, macro-F1 and accuracy when compared to baselines.","Title: Identifying Brain Networks at Multiple Time Scales via Deep Recurrent Neural Network.\nYear: 2019\n\nAbstract: For decades, task-based functional magnetic resonance imaging (tfMRI) has been a powerful noninvasive tool to explore the organizational architecture of human brain function. Researchers have developed a variety of brain network analysis methods for tfMRI data, including the general linear model (GLM), independent component analysis (ICA) and sparse representation methods. However, these shallow models are limited in faithful reconstruction and modeling of the hierarchical and temporal structures of brain networks, as demonstrated in more and more studies. Recently, recurrent neural networks (RNNs) exhibit great ability of modeling hierarchical and temporal dependency features in the machine learning field, which might be suitable for tfMRI data modeling. To explore such possible advantages of RNNs for tfMRI data, we propose a novel framework of deep recurrent neural network (DRNN) to model the functional brain networks from tfMRI data. Experimental results on the motor task tfMRI data of Human Connectome Project 900 subjects release demonstrated that the proposed DRNN can not only faithfully reconstruct functional brain networks, but also identify more meaningful brain networks with multiple time scales which are overlooked by traditional shallow models. In general, this work provides an effective and powerful approach to identifying functional brain networks of multiple time scales from fMRI data.","Title: An Efficient and Secure Two-Factor Password Authentication Scheme With Card Reader(Terminal) Verification.\nYear: 2018\n\nAbstract: With regard to the privacy of client-server communication systems, most research works have concentrated on authentication to guarantee security. Among the investigated schemes, two-factor password authentication has been a major focus and has undergone considerable development. Two-factor password authentication is a process in which both a password and a physical object are used for authentication to achieve a higher level of security. However, these methods are still subject to some security vulnerabilities, such as malicious card reader attacks, man-in-the-middle attacks, and a lack of perfect forward secrecy. Moreover, although there are many evaluation criteria, there still lacks a set of universal criteria. To address these issues, a two-factor password authentication scheme is proposed in the context of practical application environment in this paper, such as side-channel attacks. Moreover, a card reader verification step is added to the authentication scheme to counteract malicious card reader attacks. In addition, the proposed scheme can resist various known attacks, including replay attacks, lost or stolen smart card attacks, and man-in-the-middle attacks. We present a detailed security analysis and comparative evaluation, and we prove the security of our scheme with Burrows-Abadi-Needham (BAN) logic. Compared with previous schemes, the main advantages of the proposed scheme are its low computational cost, guaranteed security, and better adaptability to actual client-server communication environments.","Title: Dilated residual encode-decode networks for image denoising.\nYear: 2018\n\nAbstract: Owing to recent advancements, very deep convolutional neural networks (CNNs) have found application in image denoising. However, while deeper models lead to better restoration performance, they are marred by a high number of parameters and increased training difficulty. To address these issues, we propose a CNN-based framework, named dilated residual encode-decode networks (DRED-Net), for image denoising, which learns direct end-to-end mappings from corrupted images to obtain clean images using few parameters. Our proposed network consists of multiple layers of convolution and deconvolution operators; in addition, we use dilated convolutions to boost the performance of our network without increasing the depth of the model or its complexity. Extensive experiments on synthetic noisy images are conducted to evaluate DRED-Net, and the results are compared with those obtained using state-of-the-art denoising methods. Our experimental results show that DRED-Net leads to results comparable with those obtained using other state-of-the-art methods for image denoising tasks. (C) 2018 SPIE and IS&T","Title: A New Entropy-Based Atrial Fibrillation Detection Method for Scanning Wearable ECG Recordings.\nYear: 2018\n\nAbstract: Entropy-based atrial fibrillation (AF) detectors have been applied for short-term electrocardiogram (ECG) analysis. However, existing methods suffer from several limitations. To enhance the performance of entropy-based AF detectors, we have developed a new entropy measure, named Entropy(AF), which includes the following improvements: (1) use of a ranged function rather than the Chebyshev function to define vector distance, (2) use of a fuzzy function to determine vector similarity, (3) replacement of the probability estimation with density estimation for entropy calculation, (4) use of a flexible distance threshold parameter, and (5) use of adjusted entropy results for the heart rate effect. Entropy(AF) was trained using the MIT-BIH Atrial Fibrillation (AF) database, and tested on the clinical wearable long-term AF recordings. Three previous entropy-based AF detectors were used for comparison: sample entropy (SampEn), fuzzy measure entropy (FuzzyMEn) and coefficient of sample entropy (COSEn). For classifying AF and non-AF rhythms in the MIT-BIH AF database, Entropy(AF) achieved the highest area under receiver operating characteristic curve (AUC) values of 98.15% when using a 30-beat time window, which was higher than COSEn with AUC of 91.86%. SampEn and FuzzyMEn resulted in much lower AUCs of 74.68% and 79.24% respectively. For classifying AF and non-AF rhythms in the clinical wearable AF database, Entropy(AF) also generated the largest values of Youden index (77.94%), sensitivity (92.77%), specificity (85.17%), accuracy (87.10%), positive predictivity (68.09%) and negative predictivity (97.18%). COSEn had the second-best accuracy of 78.63%, followed by an accuracy of 65.08% in FuzzyMEn and an accuracy of 59.91% in SampEn. The new proposed Entropy(AF) also generated highest classification accuracy when using a 12-beat time window. In addition, the results from time cost analysis verified the efficiency of the new Entropy(AF). This study showed the better discrimination ability for identifying AF when using Entropy(AF) method, indicating that it would be useful for the practical clinical wearable AF scanning.","Title: Predicting Topic Participation By Jointly Learning User Intrinsic And Extrinsic Preference\nYear: 2019\n\nAbstract: Understanding the preferences of social media participants plays a crucial role in many business applications. A specific aspect of interest is to predict which topics a particular user is more likely to be involved in. Existing efforts on such topic participation forecasting mainly focus on learning from historical user-generated texts to infer their preferred topics, or leverage on an information propagation theory on networks to predict the topics of potential interest. However, jointly utilizing both the sources of data to provide a holistic prediction for such a task has not been exploited. We present a novel joint learning framework that takes advantage of both users' intrinsic (learned from their past social media postings) and extrinsic preference (learned from the social network influence) and that embeds them into low-dimensional space vectors. To facilitate effective learning, we encode latent continuous embedded vectors into binary ones via locality-sensitive hashing. Furthermore, to explain the predictions made by our \"black-box\" model, we investigate the importance of each training sample on the topic prediction performance of a testing instance to demonstrate its interpretability. The experiments conducted on datasets collected from several popular social media platforms demonstrate the effectiveness of our proposed method when compared with existing baselines.","Title: ORACLE: Optimized Radio clAssification through Convolutional neuraL nEtworks.\nYear: 2018\n\nAbstract: This paper describes the architecture and performance of ORACLE, an approach for detecting a unique radio from a large pool of bit-similar devices (same hardware, protocol, physical address, MAC ID) using only IQ samples at the physical layer. ORACLE trains a convolutional neural network (CNN) that balances computational time and accuracy, showing 99% classification accuracy for a 16-node USRP X310 SDR testbed and an external database of >100 COTS WiFi devices. Our work makes the following contributions: (i) it studies the hardware-centric features within the transmitter chain that causes IQ sample variations; (ii) for an idealized static channel environment, it proposes a CNN architecture requiring only raw IQ samples accessible at the front-end, without channel estimation or prior knowledge of the communication protocol; (iii) for dynamic channels, it demonstrates a principled method of feedback-driven transmitter-side modifications that uses channel estimation at the receiver to increase differentiability for the CNN classifier. The key innovation here is to intentionally introduce controlled imperfections on the transmitter side through software directives, while minimizing the change in bit error rate. Unlike previous work that imposes constant environmental conditions, ORACLE adopts the ‘train once deploy anywhere’ paradigm with near-perfect device classification accuracy.","Title: Accelerating Deep Neural Network Training for Action Recognition on a Cluster of GPUs\nYear: 2018\n\nAbstract: Due to the additional temporal dimension, large-scale video action recognition is even more challenging than image recognition and typically takes days to train on modern GPUs even for modest-sized datasets. We propose algorithms and techniques to accelerate training of deep neural networks for action recognition on a cluster of GPUs. In terms of convergence and scaling, our distributed training algorithm with adaptive batch size is provably superior to popular asynchronous stochastic gradient descent algorithms. The convergence analysis of our algorithm shows it is possible to reduce communication cost and at the same time minimize the number of iterations needed for convergence. We customize the Adam optimizer for our distributed algorithm to improve efficiency. In addition, we employ transfer-learning to further reduce training time while improving validation accuracy. Compared with the base-line single-GPU stochastic gradient descent implementation of the two-stream training approach, our implementation achieves super-linear speedups on 16 GPUs while improving validation accuracy. For the UCFI0l and HMDB51 datasets, the validation accuracies achieved are 93.1 % and 67.9% respectively. As far as we know, these are the highest accuracies achieved with the two-stream approach that does not involve computationally expensive 3D convolutions or pretraining on much larger datasets.","Title: Shaping Gain of Lattices Based on Convolutional Codes and Construction A\nYear: 2018\n\nAbstract: This paper studies the shaping gain and the performance-complexity trade-off of convolutional code lattices, lattices that are based on convolutional codes and Construction A. Generator polynomials for convolutional codes which provide the best-found shaping gain are presented, for various code rates, memory orders and lattice dimensions. Results are based on exhaustive searches. The obtained shaping gains usually exceed that of convolutional codes good for coding. Convolutional code lattices with memory order 7 can provide a shaping gain of 1.20 dB (up to a possible 1.53 dB theoretical maximum) at dimension 256, which is higher than the 1.03 dB shaping gain of the Leech lattice. While convolutional code lattices based on rate 1/2 convolutional codes have the best shaping gain for a fixed memory order, we show that using rate 1/3 convolutional codes produces a more favorable performance-complexity trade-off.","Title: Doping Ag in ZnO Nanorods to Improve the Performance of Related Enzymatic Glucose Sensors.\nYear: 2017\n\nAbstract: In this paper, the performance of a zinc oxide (ZnO) nanorod-based enzymatic glucose sensor was enhanced with silver (Ag)-doped ZnO (ZnO-Ag) nanorods. The effect of the doped Ag on the surface morphologies, wettability, and electron transfer capability of the ZnO-Ag nanorods, as well as the catalytic character of glucose oxidase (GOx) and the performance of the glucose sensor was investigated. The results indicate that the doped Ag slightly weakens the surface roughness and hydrophilicity of the ZnO-Ag nanorods, but remarkably increases their electron transfer ability and enhances the catalytic character of GOx. Consequently, the combined effects of the above influencing factors lead to a notable improvement of the performance of the glucose sensor, that is, the sensitivity increases and the detection limit decreases. The optimal amount of the doped Ag is determined to be 2 mM, and the corresponding glucose sensor exhibits a sensitivity of 3.85 A/(mMcm(2)), detection limit of 1.5 M, linear range of 1.5 x 10(-3)-6.5 mM, and Michaelis-Menten constant of 3.87 mM. Moreover, the glucose sensor shows excellent selectivity to urea, ascorbic acid, and uric acid, in addition to displaying good storage stability. These results demonstrate that ZnO-Ag nanorods are promising matrix materials for the construction of other enzymatic biosensors.","Title: A Benchmark for Comparing Precision Medicine Methods in Thyroid Cancer Diagnosis using Tissue Microarrays.\nYear: 2018\n\nAbstract: Motivation: The aim of precision medicine is to harness new knowledge and technology to optimize the timing and targeting of interventions for maximal therapeutic benefit. This study explores the possibility of building AI models without precise pixel-level annotation in prediction of the tumor size, extrathyroidal extension, lymph node metastasis, cancer stage and BRAF mutation in thyroid cancer diagnosis, providing the patients' background information, histopathological and immunohistochemical tissue images. Results: A novel framework for objective evaluation of automatic patient diagnosis algorithms has been established under the auspices of the IEEE International Symposium on Biomedical Imaging 2017-A Grand Challenge for Tissue Microarray Analysis in Thyroid Cancer Diagnosis. Here, we present the datasets, methods and results of the challenge and lay down the principles for future uses of this benchmark. The main contributions of the challenge include the creation of the data repository of tissue microarrays; the creation of the clinical diagnosis classification data repository of thyroid cancer; and the definition of objective quantitative evaluation for comparison and ranking of the algorithms. With this benchmark, three automatic methods for predictions of the five clinical outcomes have been compared, and detailed quantitative evaluation results are presented in this paper. Based on the quantitative evaluation results, we believe automatic patient diagnosis is still a challenging and unsolved problem.","Title: QTCP: Adaptive Congestion Control with Reinforcement Learning\nYear: 2019\n\nAbstract: Next generation network access technologies and Internet applications have increased the challenge of providing satisfactory quality of experience for users with traditional congestion control protocols. Efforts on optimizing the performance of TCP by modifying the core congestion control method depending on specific network architectures or apps do not generalize well under a wide range of network scenarios. This limitation arises from the rule-based design principle, where the performance is linked to a pre-decided mapping between the observed state of the network to the corresponding actions. Therefore, these protocols are unable to adapt their behavior in new environments or learn from experience for better performance. We address this problem by integrating a reinforcement-based Q-learning framework with TCP design in our approach called QTCP. QTCP enables senders to gradually learn the optimal congestion control policy in an on-line manner. QTCP does not need hard-coded rules, and can therefore generalize to a variety of different networking scenarios. Moreover, we develop a generalized Kanerva coding function approximation algorithm, which reduces the computation complexity of value functions and the searchable size of the state space. We show that QTCP outperforms the traditional rule-based TCP by providing 59.5% higher throughput while maintaining low transmission latency.","Title: Janus: A Multi-TCP Framework for Application-Aware Optimization in Mobile Networks\nYear: 2019\n\nAbstract: As the dominant protocol on the Internet, TCP has attracted significant attention and has been implemented in various ways, each of which optimizes for a single objective such as high throughput or low delay. However, in today's mobile networks that carry traffic from diverse types of flows, this approach may lead to misconfiguration of TCP congestion control algorithms and further degrade performance for many applications. In this paper, we propose Janus, a new transport-layer framework that automatically selects among existing congestion control variants to optimize traffic in accordance with application demands. Janus is easy to deploy because it reuses existing, well-tested congestion control implementations, and does not require any in-network or client-side changes. To explore the potential for this approach, we implement Janus in the Linux kernel and extensively evaluate its performance with both emulated and real Internet traffic. We show Janus outperforms alternative protocols by offering fast convergence times in response to changing network conditions, achieving 5-10X lower delay with comparable or higher throughput. Our approach also significantly improves user-perceived performance according to QoE metrics, with up to 5X fewer interruptions for video streaming applications and 2X faster page loading for web-browsing applications.","Title: Decentralized robust optimal control for modular robot manipulators via critic-identifier structure-based adaptive dynamic programming\nYear: 2020\n\nAbstract: This paper presents a decentralized robust optimal control method for modular robot manipulators (MRMs) via a critic-identifier structure-based adaptive dynamic programming (ADP) scheme. The robust control problem of MRMs is transformed into an optimal compensation control issue, which consists of model-based compensation control, identifier-based learning control and ADP-based optimal control. The dynamic model of MRMs is deployed for each joint module where the local dynamic information is utilized to design the model compensation controller. A neural network (NN) identifier is established to approximate the interconnected dynamic coupling. Based on ADP and local online policy iteration algorithm, the Hamiltonian–Jacobi–Bellman equation is solved by constructing a critic NN, and then the approximate optimal control policy derivation is possible. The closed-loop robotic system is asymptotic stable by the implementation of a set of developed decentralized control policies. Simulations are presented to demonstrate the effectiveness of the proposed method.","Title: Robust visual tracking for planar objects using gradient orientation pyramid.\nYear: 2019\n\nAbstract: Direct visual tracking (DVT) for planar objects is a fundamental problem in computer vision. DVT methods often formulate tracking as an image registration problem, where image intensities are directly used to match two images. However, these methods are usually sensitive to illumination changes as they assume intensities are constant. The gradient orientation (GO) was proven to be insensitive to illumination variations in previous reports. We further confirmed that the GO's robustness can be significantly improved when the pyramid technique is employed. We present a robust DVT method, named gradient orientation pyramid efficient second-order minimization (GOP-ESM), based on the proposed gradient orientation pyramid descriptor. GOP-ESM takes the advantages of the robust feature descriptors and the efficient second-order minimization method as to enhance tracking robustness and accuracy. We also published a tracking dataset for planar objects with illumination changes (POIC). The evaluations on the proposed POIC dataset and the other two public benchmark datasets demonstrated that GOP-ESM outperforms the state-of-the-art tracking methods against various environmental variations, especially illumination changes. (C) 2019 SPIE and IS&T","Title: Animated Mesh Simplification Based On Motion Features In Visual Sensor Networks\nYear: 2019\n\nAbstract: The three-dimensional animated model is widely used in scientific visualization, entertainment, and virtual applications, especially in visual sensor networks. The main purpose of simplification is to capture the shape sequence of an object with very few elements while preserving the overall shape. As three-dimensional animated mesh is time-varying in all frames, the trade-off between the temporal coherence and geometric distortion must be considered to develop simplification algorithm. In this article, a novel three-dimensional animated mesh simplification algorithm based on motion features is presented. Here, motion features are the connection areas of the relative movement consisted of vertices and edges. Motion feature extraction is to find a subgraph that has movement property. Dihedral angle of the edge through all frames is used to determine whether an edge is connected or not to the movement parts. Then, a rotation connected graph is defined to extract motion features. Traveling this graph, all motion features can be extracted. Based on the motion features, animated quadric error metric is created and quadric error matrix is built through all frames. Compared with the other methods, the important advantages of this method are high-efficiency simplification process and smoother simplification effects. It is suitable to be used in real-time applications. Experiment results show that the 3D animated mesh simplification effects by our method are satisfactory.","Title: Conditional progressive network for clothing parsing.\nYear: 2019\n\nAbstract: Clothing parsing is significant to many clothing applications. Recently, a lot of clothing parsing methods have been presented, which explore the innovation of the parsing pipeline or try to find more specific prior information. Although these methods perform well in some benchmarks, a few challenging problems have not been solved yet, such as the complicated mutual interference among labels. In this study, the authors propose a Conditional Progressive Network to parse clothing in different scales and prevent the mutual interference among labels. The authors’ solution consists of three sub-networks, including Conditional Parsing Network (CPN), Pose Estimation Network (PEN) and Label Transform Network (LTN). Specifically, the CPN module generates the intermediate parsing result in the form of the multiple progressive stages, which combines with the previous outputs in each stage and the specific prior conditions. The PEN module provides a series of heat maps about the human pose information. The LTN module suppresses the redundant labels to avoid the mutual interference among labels. They demonstrate their solution in parsing the fashion clothing cases on the ATR and the Fashion dataset. In their experiments, their method obtains a better performance than the state-of-the-art methods.","Title: Variational Session-based Recommendation Using Normalizing Flows\nYear: 2019\n\nAbstract: We present a novel generative Session-Based Recommendation (SBR) framework, called VAriational SEssion-based Recommendation (VASER) - a non-linear probabilistic methodology allowing Bayesian inference for flexible parameter estimation of sequential recommendations. Instead of directly applying extended Variational AutoEncoders (VAE) to SBR, the proposed method introduces normalizing flows to estimate the probabilistic posterior, which is more effective than the agnostic presumed prior approximation used in existing deep generative recommendation approaches. VASER explores soft attention mechanism to upweight the important clicks in a session. We empirically demonstrate that the proposed model significantly outperforms several state-of-the-art baselines, including the recently-proposed RNN/VAE-based approaches on real-world datasets.","Title: Context-aware Variational Trajectory Encoding and Human Mobility Inference\nYear: 2019\n\nAbstract: Unveiling human mobility patterns is an important task for many downstream applications like point-of-interest (POI) recommendation and personalized trip planning. Compelling results exist in various sequential modeling methods and representation techniques. However, discovering and exploiting the context of trajectories in terms of abstract topics associated with the motion can provide a more comprehensive understanding of the dynamics of patterns. We propose a new paradigm for moving pattern mining based on learning trajectory context, and a method - Context-Aware Variational Trajectory Encoding and Human Mobility Inference (CATHI) - for learning user trajectory representation via a framework consisting of: (1) a variational encoder and a recurrent encoder; (2) a variational attention layer; (3) two decoders. We simultaneously tackle two subtasks: (T1) recovering user routes (trajectory reconstruction); and (T2) predicting the trip that the user would travel (trajectory prediction). We show that the encoded contextual trajectory vectors efficiently characterize the hierarchical mobility semantics, from which one can decode the implicit meanings of trajectories. We evaluate our method on several public datasets and demonstrate that the proposed CATHI can efficiently improve the performance of both subtasks, compared to state-of-the-art approaches.","Title: Improving Top-K Recommendation via JointCollaborative Autoencoders\nYear: 2019\n\nAbstract: In this paper, we propose a Joint Collaborative Autoencoder framework that learns both user-user and item-item correlations simultaneously, leading to a more robust model and improved top-K recommendation performance. More specifically, we show how to model these user-item correlations and demonstrate the importance of careful normalization to alleviate the influence of feedback heterogeneity. Further, we adopt a pairwise hinge-based objective function to maximize the top-K precision and recall directly for top-K recommenders. Finally, a mini-batch optimization algorithm is proposed to train the proposed model. Extensive experiments on three public datasets show the effectiveness of the proposed framework over state-of-the-art non-neural and neural alternatives.","Title: Predicting Human Mobility via Variational Attention\nYear: 2019\n\nAbstract: An important task in Location based Social Network applications is to predict mobility - specifically, user's next point-of-interest (POI) - challenging due to the implicit feedback of footprints, sparsity of generated check-ins, and the joint impact of historical periodicity and recent check-ins. Motivated by recent success of deep variational inference, we propose VANext (Variational Attention based Next) POI prediction: a latent variable model for inferring user's next footprint, with historical mobility attention. The variational encoding captures latent features of recent mobility, followed by searching the similar historical trajectories for periodical patterns. A trajectory convolutional network is then used to learn historical mobility, significantly improving the efficiency over often used recurrent networks. A novel variational attention mechanism is proposed to exploit the periodicity of historical mobility patterns, combined with recent check-in preference to predict next POIs. We also implement a semi-supervised variant - VANext-S, which relies on variational encoding for pre-training all current trajectories in an unsupervised manner, and uses the latent variables to initialize the current trajectory learning. Experiments conducted on real-world datasets demonstrate that VANext and VANext-S outperform the state-of-the-art human mobility prediction models.","Title: A Distributed Hierarchical SGD Algorithm with Sparse Global Reduction.\nYear: 2019\n\nAbstract: Reducing communication overhead is a big challenge for large-scale distributed training. To address this issue, we present a hierarchical averaging stochastic gradient descent (Hier-AVG) algorithm that reduces global reductions (averaging) by employing less costly local reductions. As a very general type of parallel SGD, Hier-AVG can reproduce several commonly adopted synchronous parallel SGD variants by adjusting its parameters. We establish standard convergence results of Hier-AVG for non-convex smooth optimization problems. Under the non-asymptotic scenario, we show that Hier-AVG with less frequent global averaging can sometimes have faster training speed. In addition, we show that more frequent local averaging with more participants involved can lead to faster training convergence. By comparing Hier-AVG with another distributed training algorithm K-AVG, we show that through deploying local averaging with less global averaging Hier-AVG can still achieve comparable training speed while constantly get better test accuracy. As a result, local averaging can serve as an alternative remedy to effectively reduce communication overhead when the number of learners is large. We test Hier-AVG with several state-of-the-art deep neural nets on CIFAR-10 to validate our analysis. Further experiments to compare Hier-AVG with K-AVG on ImageNet-1K also show Hier-AVGu0027s superiority over K-AVG.","Title: Design of Low-Complexity 3-D Underwater Imaging System With Sparse Planar Arrays\nYear: 2019\n\nAbstract: The development of a real-time 3-D underwater imaging system with a planar array is restricted by the huge hardware cost and computational burden associated with the large number of elements required. In this paper, a new design of low-complexity 3-D underwater imaging system is proposed, involving two key parts: a special sparse array with low hardware cost and an efficient beamforming with low c...","Title: The Sup-norm Perturbation of HOSVD and Low Rank Tensor Denoising\nYear: 2019\n\nAbstract: The higher order singular value decomposition (HOSVD) of tensors is a generalization of matrix SVD. The perturbation analysis of HOSVD under random noise is more delicate than its matrix counterpart. Recently, polynomial time algorithms have been proposed where statistically optimal estimates of the singular subspaces and the low rank tensors are attainable in the Euclidean norm. In this article, we analyze the sup-norm perturbation bounds of HOSVD and introduce estimators of the singular subspaces with sharp deviation bounds in the sup-norm. We also investigate a low rank tensor denoising estimator and demonstrate its fast convergence rate with respect to the entry-wise errors. The sup-norm perturbation bounds reveal unconventional phase transitions for statistical learning applications such as the exact clustering in high dimensional Gaussian mixture model and the exact support recovery in sub-tensor localizations. In addition, the bounds established for HOSVD also elaborate the one-sided sup-norm perturbation bounds for the singular subspaces of unbalanced (or fat) matrices.","Title: Disentangled Network Alignment with Matching Explainability\nYear: 2019\n\nAbstract: Network alignment (NA) is a fundamental problem in many application domains – from social networks, through biology and communications, to neuroscience. The main objective is to identify common nodes and most similar connections across multiple networks (resp. graphs). Many of the existing efforts focus on efficient anchor node linkage by leveraging various features and optimizing network mapping functions with the pairwise similarity between anchor nodes. Despite the recent advances, there still exist two kinds of challenges: (1) entangled node embeddings, arising from the contradictory goals of NA: embedding proximal nodes in a closed form for representation in a single network vs. discriminating among them when mapping the nodes across networks; and (2) lack of interpretability about the node matching and alignment, essential for understanding prediction tasks. We propose d NAME (disentangled Network Alignment with Matching Explainability) – a novel solution for NA in heterogeneous networks settings, based on a matching technique that embeds nodes in a disentangled and faithful manner. The NA task is cast as an adversarial optimization problem which learns a proximity-preserving model locally around the anchor nodes, while still being discriminative. We also introduce a method to explain our semi-supervised model with the theory of robust statistics, by tracing the importance of each anchor node and its explanations on the NA performance. This is extensible to many other NA methods, as it provides model interpretability. Experiments conducted on several public datasets show that d NAME outperforms the state-of-the-art methods in terms of both network alignment precision and node matching ranking.","Title: Meta-GNN: On Few-shot Node Classification in Graph Meta-learning.\nYear: 2019\n\nAbstract: Meta-learning has received a tremendous recent attention as a possible approach for mimicking human intelligence, i.e., acquiring new knowledge and skills with little or even no demonstration. Most of the existing meta-learning methods are proposed to tackle few-shot learning problems such as image and text, in rather Euclidean domain. However, there are very few works applying meta-learning to non-Euclidean domains, and the recently proposed graph neural networks (GNNs) models do not perform effectively on graph few-shot learning problems. Towards this, we propose a novel graph meta-learning framework -- Meta-GNN -- to tackle the few-shot node classification problem in graph meta-learning settings. It obtains the prior knowledge of classifiers by training on many similar few-shot learning tasks and then classifies the nodes from new classes with only few labeled samples. Additionally, Meta-GNN is a general model that can be straightforwardly incorporated into any existing state-of-the-art GNN. Our experiments conducted on three benchmark datasets demonstrate that our proposed approach not only improves the node classification performance by a large margin on few-shot learning problems in meta-learning paradigm, but also learns a more general and flexible model for task adaption.","Title: Information Diffusion Prediction via Recurrent Cascades Convolution\nYear: 2019\n\nAbstract: Effectively predicting the size of an information cascade is critical for many applications spanning from identifying viral marketing and fake news to precise recommendation and online advertising. Traditional approaches either heavily depend on underlying diffusion models and are not optimized for popularity prediction, or use complicated hand-crafted features that cannot be easily generalized to different types of cascades. Recent generative approaches allow for understanding the spreading mechanisms, but with unsatisfactory prediction accuracy. To capture both the underlying structures governing the spread of information and inherent dependencies between re-tweeting behaviors of users, we propose a semi-supervised method, called Recurrent Cascades Convolutional Networks (CasCN), which explicitly models and predicts cascades through learning the latent representation of both structural and temporal information, without involving any other features. In contrast to the existing single, undirected and stationary Graph Convolutional Networks (GCNs), CasCN is a novel multi-directional/dynamic GCN. Our experiments conducted on real-world datasets show that CasCN significantly improves the prediction accuracy and reduces the computational cost compared to state-of-the-art approaches.","Title: Motion Based Inference of Social Circles via Self-Attention and Contextualized Embedding.\nYear: 2019\n\nAbstract: Extracting knowledge from human mobility data is an important task for many downstream applications such as point-of-interest recommendation, motion trace identification, and personalized trip planning. A specific problem that has recently spurred research interest is the so-called Social Circle Inference from Mobility data (SCIM), aiming at inferring relationships among users based on mobility data and without any explicit structured network information. The existing methods either require partial social ties or fail to model the implicit correlations between user links, thereby suffering from critical inference bias. We present a novel SCIM framework, called SCIM via self-Attention and Contextualizedembedding (SCIMAC) - a methodology capturing multiple aspects of users' check-in behavior and complex motion patterns of different users. Instead of directly applying the recurrent model on training user trajectories, the proposed method introduces a new module for context-aware check-in representation learning by adaptively incorporating the internal states of the recurrent layers, which is more effective than the context-independent check-in embedding used in existing social circle inference approaches. To model the underlying correlations between labels, SCIMAC leverages a more sophisticated label embedding technique to adjust the penalties for correlated users, enabling a better understanding of the user's hierarchy in the label space, and alleviating the inference bias. We empirically demonstrate that our SCIMAC model significantly outperforms several state-of-the-art baselines on real-world datasets.","Title: Quantifying Layerwise Information Discarding of Neural Networks.\nYear: 2019\n\nAbstract: This paper presents a method to explain how input information is discarded through intermediate layers of a neural network during the forward propagation, in order to quantify and diagnose knowledge representations of pre-trained deep neural networks. We define two types of entropy-based metrics, i.e., the strict information discarding and the reconstruction uncertainty, which measure input information of a specific layer from two perspectives. We develop a method to enable efficient computation of such entropy-based metrics. Our method can be broadly applied to various neural networks and enable comprehensive comparisons between different layers of different networks. Preliminary experiments have shown the effectiveness of our metrics in analyzing benchmark networks and explaining existing deep-learning techniques.","Title: Decentralized Robust Optimal Control For Modular Robot Manipulators Based On Zero-Sum Game With Adp\nYear: 2019\n\nAbstract: In this paper, a decentralized robust zero-sum optimal control method is proposed for modular robot manipulators (MRMs) based on the adaptive dynamic programming (ADP) approach. The dynamic model of MRMs is formulated via joint torque feedback (JTF) technique that is deployed for each joint module, in which the local dynamic information is used to design the model compensation controller. An uncertainty decomposition-based robust control is developed to compensate the model uncertainties, and then the robust optimal control problem of MRMs with uncertain environments can be transformed into a two-player zero-sum optimal control one. According to the ADP algorithm, the Hamilton-Jacobi-Isaacs (HJI) equation is solved by constructing actioncritic neural networks (NNs) and then the approximate optimal control policy derivation is possible. Experiments are conducted to verify the effectiveness of the proposed method.","Title: Active Optimal Fault-Tolerant Control Method For Multi-Fault Concurrent Modular Manipulator Based On Adaptive Dynamic Programming\nYear: 2019\n\nAbstract: In this paper, a novel active optimal fault-tolerant control (FTC) scheme is designed based on adaptive dynamic programming (ADP) for modular manipulator when sensor and actuator faults are concurrency. Firstly, the sensor fault is transformed into the pseudo-actuator fault by constructing a nonlinear transformation with diffeomorphism theory. Secondly, the faults estimated by the adaptive fault observer are applied to establish an improved performance index function. Next, the online policy iteration (PI) algorithm is used to solve the Hamilton-Jacobi-Bellman (HJB) equation via establishing a critic neural network. The optimal fault-tolerant controller is proved to be uniformly ultimately bounded (UUB) based on Lyapunov stable theory. Finally, the effectiveness of the proposed multi-fault-tolerant control algorithm is verified by simulation results.","Title: Information Cascades Modeling via Deep Multi-Task Learning\nYear: 2019\n\nAbstract: Effectively modeling and predicting the information cascades is at the core of understanding the information diffusion, which is essential for many related downstream applications, such as fake news detection and viral marketing identification. Conventional methods for cascade prediction heavily depend on the hypothesis of diffusion models and hand-crafted features. Owing to the significant recent successes of deep learning in multiple domains, attempts have been made to predict cascades by developing neural networks based approaches. However, the existing models are not capable of capturing both the underlying structure of a cascade graph and the node sequence in the diffusion process which, in turn, results in unsatisfactory prediction performance. In this paper, we propose a deep multi-task learning framework with a novel design of shared-representation layer to aid in explicitly understanding and predicting the cascades. As it turns out, the learned latent representation from the shared-representation layer can encode the structure and the node sequence of the cascade very well. Our experiments conducted on real-world datasets demonstrate that our method can significantly improve the prediction accuracy and reduce the computational cost compared to state-of-the-art baselines.","Title: Reducing global reductions in large-scale distributed training\nYear: 2019\n\nAbstract: Current large-scale training of deep neural networks typically employs synchronous stochastic gradient descent that incurs large communication overhead. Instead of optimizing reduction routines as done in recent studies, we propose algorithms that do not require frequent global reductions. We first show that reducing the global reduction frequency works as an effective regularization technique that improves generalization of adaptive optimizers. We then propose an algorithm that reduces the global reduction frequency by employing local reductions on a subset of learners. In addition, to maximize the effect of reduction on convergence, we introduce reduction momentum that further accelerates convergence.\n\nOur experiment with the CIFAR-10 dataset shows that for the K-step averaging algorithm extremely sparse reductions help bridge the generalization gap. With 6 GPUs, in comparison to regular synchronous implementations, our implementation reduces more than 99% of global reductions. Further, we show that with 32 GPUs, our implementation reduces the number of global reductions by half. Experimenting with the ImageNet-1K dataset, we show that combining local reductions with global reductions and applying reduction momentum can further reduce global reductions by up to 62% for the same validation accuracy achieved in comparison to K-step averaging. With 400 GPUs global reduction frequency is reduced to once per 102K samples.","Title: Hybrid graph convolutional networks with multi-head attention for location recommendation\nYear: 2020\n\nAbstract: Recommending yet-unvisited points of interest (POIs) which may be of interest to users is one of the fundamental applications in location-based social networks. It mainly replies on the understanding of users, POIs, and their interactions. Previous studies either develop matrix factorization-based approaches or utilize deep learning frameworks to learn better representation of users and POIs in order to estimate users' latent preference. However, most of existing methods still confront the challenges like in traditional recommender systems, such as data sparsity and cold-start. In particular, they have difficulties in fully utilizing rich semantic information, such as social influence, geographical constraints and interactions between users and POIs. To fill this research gap, we propose a new recommendation framework - Hybrid Graph convolutional networks with Multi-head Attention for POI recommendation (HGMAP). HGMAP constructs a spatial graph based on the geographical distance between pairs of POIs and leverages Graph Convolutional Networks (GCNs) to express the high-order connectivity among POIs, which not only incorporates the spatial constraints but also provides an effective way to alleviate the sparse check-in problem. In addition, HGMAP exploits the user social relationship with another GCN and differentiates user preference over different aspects of POIs with a multi-head attention mechanism. We conducted extensive experiments on three public datasets and the results demonstrate that HGMAP significantly improves the recommendation performance over several state-of-the-art models, for example, up to approximately 4.8% and 7% forPrecision@10andRecall@10, respectively.","Title: Multi-Task Learning By Leveraging The Semantic Information\nYear: 2021\n\nAbstract: One crucial objective of multi-task learning is to align distributions across tasks so that the information between them can be transferred and shared. However, existing approaches only focused on matching the marginal feature distribution while ignoring the semantic information, which may hinder the learning performance. To address this issue, we propose to leverage the label information in multi-task learning by exploring the semantic conditional relations among tasks. We first theoretically analyze the generalization bound of multi-task learning based on the notion of Jensen-Shannon divergence, which provides new insights into the value of label information in multi-task learning. Our analysis also leads to a concrete algorithm that jointly matches the semantic distribution and controls label distribution divergence. To confirm the effectiveness of the proposed method, we first compare the algorithm with several baselines on some benchmarks and then test the algorithms under label space shift conditions. Empirical results demonstrate that the proposed method could outperform most baselines and achieve state-of-the-art performance, particularly showing the benefits under the label shift conditions.","Title: Overcoming Catastrophic Forgetting In Graph Neural Networks With Experience Replay\nYear: 2021\n\nAbstract: Graph Neural Networks (GNNs) have recently received significant research attention due to their superior performance on a variety of graph-related learning tasks. Most of the current works focus on either static or dynamic graph settings, addressing a single particular task, e.g., node/graph classification, link prediction. In this work, we investigate the question: can GNNs be applied to continuously learning a sequence of tasks? Towards that, we explore the Continual Graph Learning (CGL) paradigm and present the Experience Replay based framework ER-GNN for CGL to alleviate the catastrophic forgetting problem in existing GNNs. ER-GNN stores knowledge from previous tasks as experiences and replays them when learning new tasks to mitigate the catastrophic forgetting issue. We propose three experience node selection strategies: mean of feature, coverage maximization, and influence maximization, to guide the process of selecting experience nodes. Extensive experiments on three benchmark datasets demonstrate the effectiveness of our ER-GNN and shed light on the incremental graph (non-Euclidean) structure learning.","Title: Portraying Citizens' Occupations And Assessing Urban Occupation Mixture With Mobile Phone Data: A Novel Spatiotemporal Analytical Framework\nYear: 2021\n\nAbstract: Mobile phone data is a typical type of big data with great potential to explore human mobility and individual portrait identification. Previous studies in population classifications with mobile phone data only focused on spatiotemporal mobility patterns and their clusters. In this study, a novel spatiotemporal analytical framework with an integration of spatial mobility patterns and non-spatial behavior, through smart phone APP (applications) usage preference, was proposed to portray citizens' occupations in Guangzhou center through mobile phone data. An occupation mixture index (OMI) was proposed to assess the spatial patterns of occupation diversity. The results showed that (1) six types of typical urban occupations were identified: financial practitioners, wholesalers and sole traders, IT (information technology) practitioners, express staff, teachers, and medical staff. (2) Tianhe and Yuexiu district accounted for most employed population. Wholesalers and sole traders were found to be highly dependent on location with the most obvious industrial cluster. (3) Two centers of high OMI were identified: Zhujiang New Town CBD and Tianhe Smart City (High-Tech Development Zone). It was noted that CBD has a more profound effect on local as well as nearby OMI, while the scope of influence Tianhe Smart City has on OMI is limited and isolated. This study firstly integrated both spatial mobility and non-spatial behavior into individual portrait identification with mobile phone data, which provides new perspectives and methods for the management and development of smart city in the era of big data.","Title: Trajectory-User Linking via Graph Neural Network\nYear: 2021\n\nAbstract: Trajectory-User Linking (TUL) refers to classifying trajectories into the corresponding generated users and has emerged as an essential spatio-temporal data mining task with a broad spectrum of applications, ranging from personalized location recommendation and trip planning to criminal behavior detection and object tracking. Despite the progress made by recent deep learning-based human mobility learning models, some critical factors related to personal context and user-location interactions have not yet been fully explored. Besides, existing works suffer from high computational cost issues due to the increased complexity of trajectory learning and contextual location embedding. In this work, we propose a novel end-to-end model called GNNTUL, composed of a graph neural network (GNN) module and a classifier, to effectively and efficiently learn human mobility and associate the traces to the users in online social networks. GNNTUL is the first GNN-based human mobility learning model exploiting implicit transition patterns behind sparse user traces in online social networks while extracting users' unique motion features and discriminating the motion traces. Extensive experiments conducted on two real-world datasets demonstrate the superiority of GNNTUL over several state-of-the-art baselines in terms of both linking accuracy and learning efficiency.","Title: Catch me if you can: A participant-level rumor detection framework via fine-grained user representation learning\nYear: 2021\n\nAbstract: Researchers have exerted tremendous effort in designing ways to detect and identify rumors automatically. Traditional approaches focus on feature engineering. They require lots of human actions and are difficult to generalize. Deep learning solutions come to help. However, they usually fail to capture the underlying structure of the rumor propagation and the influence of all participants involved in the spreading chain. In this study, we propose a novel participant-level rumor detection framework. It explicitly models and integrates various fine-grained user representations (i.e., user influence, susceptibility, and temporal information) of all participants from the propagation threads via deep representation learning. Experiments conducted on real-world datasets demonstrate a significant accuracy improvement of our approach. Theoretically, we contribute to the effective usage of data science and analytics for social information diffusion design, particularly rumor detection. Practically, our results can be used to improve the quality of rumor detection services for social platforms.","Title: TRAFFIC SPEED FORECASTING VIA SPATIO-TEMPORAL ATTENTIVE GRAPH ISOMORPHISM NETWORK\nYear: 2021\n\nAbstract: Traffic forecasting is of particular interest in intelligent transportation systems (ITS). This problem is challenging owing to the complicated spatio-temporal dependencies between different areas in a road sensor network. Previous approaches have applied various deep learning methods for traffic forecasting, e.g., leveraging graph convolutional networks (GCNs) for spatial correlation modeling and utilizing recurrent neural networks (RNNs) to capture temporal traffic evolutions. However, the existing GCN-based models can not adequately distinguish the non-Euclidean topological structure of road traffic and are easily affected by random traffic noise. This work proposes an end-to-end framework to capture spatial dependencies through graph isomorphism network, while explicitly taking network topologic similarities into account and leveraging symmetric traffic for learning the traffic conditions. Extensive experiments on two real-world traffic datasets demonstrate the superiority of our proposed approach.","Title: INFERRING HIGH-RESOLUTIONAL URBAN FLOW WITH INTERNET OF MOBILE THINGS\nYear: 2021\n\nAbstract: Monitoring urban flow timely and accurately is crucial for many industrial applications - from urban planning to traffic control in the smart cities. This work introduces a new method for inferring fine-grained urban flow with the internet of mobile things such as taxis and bikes. We tackle the problem from a new perspective and present a novel deep learning method UrbanODE (Urban flow inference with Neural Ordinary Differential Equations). Furthermore, UrbanODE provides a flexible balance between flow inference accuracy and computational efficiency, which is important in computation restricted scenarios such as pervasive edge computing. Extensive evaluations on real-world traffic flow data demonstrate the superiority of the proposed method.","Title: PROBABILISTIC GRAPH NEURAL NETWORKS FOR TRAFFIC SIGNAL CONTROL\nYear: 2021\n\nAbstract: Intelligent traffic signal control is crucial for efficient transportation systems. Recent studies use reinforcement learning (RL) to coordinate traffic signals and improve traffic signal cooperation. However, they either design the state of agents in a heuristic manner or model traffic dynamics in a deterministic way. This work presents a variational graph learning model TSC-GNN (Traffic Signal Control via probabilistic Graph Neural Networks) to learn the latent representations of agents and generate Q-value while taking traffic uncertainty conditions into account. Besides, we explain the rationality behind our state design using transportation theory. Experimental results conducted on real-world datasets demonstrate our model's superiority, e.g., it achieves more than 8% traffic efficiency improvement compared with the state-of-the-art baselines.","Title: Towards Predicting Vehicular Data Consumption\nYear: 2021\n\nAbstract: Combining in-car multiple sensors measuring parameters that can be used to improve both safety and efficiency with a plethora of external data sources (e.g., traffic conditions, weather) which, if properly used, can significantly improve the overall trip experience. One source that can help the navigation and provide "context awareness", especially for autonomous driving, are the High Definition (...","Title: Analysis Of Propagation And Distribution Characteristics Of Leakage Acoustic Waves In Water Supply Pipelines\nYear: 2021\n\nAbstract: Leakage detection methods based on the analysis of leakage acoustic signals provide an effective technical approach for detecting small leaks in water supply pipelines. From a technical perspective, the study of the propagation characteristics of acoustic waves generated by the leakage in the water supply pipeline is necessary for detecting the leak location on the basis of acoustic signals. In this study, a 3D transient leakage acoustic wave propagation equation was derived by combining the principles of fluid dynamics and Lighthill acoustic analogy theory. The propagation of the leakage-induced noise in water supply pipeline was modelled theoretically. We simulated the propagation of a leakage acoustic wave under different conditions for different target scenarios encountered in actual pipeline inspections. Specifically, we analysed the effect of different factors, such as the pipe size and acoustic source characteristics, on acoustic propagation. Finally, the simulated experiments were practically performed using a self-designed simulated water supply pipeline and self-developed spherical water supply pipeline detector to validate the simulation analysis. The results of this study provide a theoretical guidance and basis for the analysis of characteristics of leakage acoustic wave signals and the recognition of leakage conditions in water supply pipelines.","Title: Self-supervised human mobility learning for next location prediction and trajectory classification\nYear: 2021\n\nAbstract: AbstractAbstractMassive digital mobility data are accumulated nowadays due to the proliferation of location-based service (LBS), which provides the opportunity of learning knowledge from human traces that can benefit a range of business and management applications, such as location recommendation, anomaly trajectory detection, crime discrimination, and epidemic tracing. However, human mobility data is usually sporadically updated since people may not frequently access mobile apps or publish the geo-tagged contents. Consequently, distilling meaningful supervised signals from sparse and noisy human mobility is the main challenge of existing models. This work presents a Self-supervised Mobility Learning (SML) framework to encode human mobility semantics and facilitate the downstream location-based tasks. SML is designed for modeling sparse and noisy human mobility trajectories, focusing on leveraging rich spatio-temporal contexts and augmented traces to improve the trajectory representations. It provides a principled way to characterize the inherent movement correlations while tackling the implicit feedback and weak supervision problems in existing model-based approaches. Besides, contrastive instance discrimination is first introduced for spatio-temporal data training by explicitly distinguishing the real user check-ins from the negative samples that tend to be wrongly predicted. Extensive experiments on two practical applications, i.e., location prediction and trajectory classification, demonstrate that our method can significantly improve the location-based services over the state-of-the-art baselines.","Title: Modeling Microscopic And Macroscopic Information Diffusion For Rumor Detection\nYear: 2021\n\nAbstract: Researchers have exerted tremendous effort in designing ways to detect and identify rumors automatically. Traditional approaches focus on feature engineering, which requires extensive manual efforts and are difficult to generalize to different domains. Recently, deep learning solutions have emerged as the de facto methods which detect online rumors in an end-to-end manner. However, they still fail to fully capture the dissemination patterns of rumors. In this study, we propose a novel diffusion-based rumor detection model, called Macroscopic and Microscopic-aware Rumor Detection, to explore the full-scale diffusion patterns of information. It leverages graph neural networks to learn the macroscopic diffusion of rumor propagation and capture microscopic diffusion patterns using bidirectional recurrent neural networks while taking into account the user-time series. Moreover, it leverages knowledge distillation technique to create a more informative student model and further improve the model performance. Experiments conducted on two real-world data sets demonstrate that our method achieves significant accuracy improvements over the state-of-the-art baseline models on rumor detection.","Title: PeriodicMove: Shift-aware Human Mobility Recovery with Graph Neural Network\nYear: 2021\n\nAbstract: ABSTRACTHuman mobility recovery is of great importance for a wide range of location-based services. However, recovering human mobility is not trivial because of three challenges: 1) complex transition patterns among locations; 2) multi-level periodicity and shifting periodicity of human mobility; 3) sparsity of the collected trajectory data. In this paper, we propose PeriodicMove, a neural attention model based on graph neural network for human mobility recovery from lengthy and sparse trajectories. In PeriodicMove, we first construct a directed graph for each trajectory and capture complex location transition patterns using graph neural network. Then, we design two attention mechanisms which capture multi-level periodicity and shifting periodicity of human mobility respectively. Finally, a spatial-aware loss function is proposed to incorporate spatial proximity into the model optimization, which alleviates the data sparsity problem. We perform extensive experiments and the evaluation results demonstrate that PeriodicMove yields significant improvements over the competitors on two representative real-life mobility datasets. In addition, by providing high-quality mobility data, our model can benefit a variety of mobility-oriented downstream applications.","Title: Vector-Quantized Autoencoder With Copula for Collaborative Filtering\nYear: 2021\n\nAbstract: BSTRACTIn theory, the variational auto-encoder (VAE) is not suitable for recommendation tasks, although it has been successfully utilized for collaborative filtering (CF) models. In this paper, we propose a Gaussian Copula-Vector Quantized Autoencoder (GC-VQAE) model that differs prior arts in two key ways: (1) Gaussian Copula helps to model the dependencies among latent variables which are used to construct a more complex distribution compared with the mean-field theory; and (2) by incorporating a vector quantisation method into encoders our model can learn discrete representations which are consistent with the observed data rather than directly sampling from the simple Gaussian distributions. Our approach is able to circumvent the \"posterior collapse'' issue and break the prior constraint to improve the flexibility of latent vector encoding and learning ability. Empirically, GC-VQAE can significantly improve the recommendation performance compared to existing state-of-the-art methods.","Title: MVSN: A Multi-view stack network for human parsing\nYear: 2021\n\nAbstract: The human parsing task is dedicated to allocating pixel-level fine-grained semantic labels. However, recent solutions are limited to fully utilize the prior information (poses and edges) and the potential information of the image data, remaining problems with ambiguous boundaries, incomplete human parts, and redundant labels. To solve the above problems, we propose a novel Multi-view Stack Network (MVSN), which is constructed by three stacks with multiple views of features included parts, edges, and pre-segmentation. Meanwhile, a channel correlator is developed to acquire the correlation between local and global information better. Comprehensive experiments and corresponding results on three public datasets show that the proposed MVSN performs favorably against the state-of-the-art methods.","Title: Forecasting Reservoir Inflow Via Recurrent Neural Odes\nYear: 2021\n\nAbstract: Forecasting reservoir inflow is critical for making many policies, ranging from flood control and agriculture irrigation to water ecology management, hydropower generation, and landslide prevention. Prior studies mainly exploit autoregressive models - e.g., recurrent neural networks (RNN) and its many variants - to model the flow time series's temporal pattern. However, existing approaches rely on regular and accurate inflow observations, which either fail to predict multiscale inflow (e.g., an hour, a day, or a month ahead prediction) or ignore the uncertainty of observations due to confounding factors such as snowmelt and precipitation. To address the limitations, we propose a novel inflow forecasting model by incorporating the uncertainty of the observations into the RNN model and the continuous-time dynamics of the latent states with neural ordinary differential equations (ODE). Our method, called FlowODE, explicitly encodes the stochasticity of hidden conditions in addition to the temporal dependencies among inflow observations. Moreover, FlowODE explores a continuum of layers instead of discrete RNNs to model the hidden states' dynamics, allowing us to infer the inflow at any time horizon flexibly. We conduct extensive experiments on the real-world datasets collected from two large-scale hydropower dams. The results show that our method consistently outperforms previous inflow forecasting models while providing adaptable predictions and a flexible balance between prediction accuracy and computational cost.","Title: Land Deformation Prediction Via Slope-Aware Graph Neural Networks\nYear: 2021\n\nAbstract: We introduce a slope-aware graph neural network (SA-GNN) to leverage continuously monitored data and predict the land displacement. Unlike general GNNs tackling tasks in the plain graphs, our method is capable of generalizing 3D spatial knowledge from InSAR point clouds. Specifically, we structure of the land surface, while preserving the spatial correlations among adjacent points. The point cloud can then be efficiently converted to a near-neighbor graph where general GNN methods can be applied to predict the displacement of the slope surface. We conducted experiments on real-world datasets and the results demonstrate that SA-GNN outperforms existing 3D CNN and point GNN methods.","Title: Rate-Optimal Subspace Estimation on Random Graphs.\nYear: 2021\n\nAbstract: Use the \"Report an Issue\" link to request a name change.","Title: Spatial Distribution and Mechanism of Urban Occupation Mixture in Guangzhou: An Optimized GeoDetector-Based Index to Compare Individual and Interactive Effects\nYear: 2021\n\nAbstract: Numerous studies have been devoted to uncovering the characteristics of resident density and urban mobility with multisource geospatial big data. However, little attention has been paid to the internal diversity of residents such as their occupations, which is a crucial aspect of urban vibrancy. This study aims to investigate the variation between individual and interactive influences of built environment factors on occupation mixture index (OMI) with a novel GeoDetector-based indicator. This study first integrated application (App) use and mobility patterns from cellphone data to portray residents' occupations and evaluate the OMI in Guangzhou. Then, the mechanism of OMI distribution was analyzed with the GeoDetector model. Next, an optimized GeoDetector-based index, interactive effect variation ratio (IEVR) was proposed to quantify the variation between individual and interactive effects of factors. The results showed that land use mixture was the dominating factor, and that land use mixture, building density, floor area ratio, road density affected the OMI distribution directly. Some interesting findings were uncovered by IEVR. The influences of cultural inclusiveness and metro accessibility were less important in factor detector result, while they were found to be the most influential in an indirect way interacting with other built environment factors. The results suggested that both \"hardware facilities \" (land use mixture, accessibility) and \"soft facilities \" (cultural inclusiveness) should be considered in planning a harmonious urban employment space and sustainable city.","Title: Uncertainty-aware network alignment\nYear: 2021\n\nAbstract: Network alignment (NA) aims to link common nodes across multiple networks and is an essential task in many graph mining applications. Despite the progress achieved by many recent works, several fundamental limitations have eluded the proper cohesive way of addressing, including matching confusion, lack of the formal treatment of uncertainty, and Point-to-Point (P2P) constraint. This study proposes a novel framework UANA (Uncertainty-Aware Network Alignment) to tackle the limitations of the existing works. By embedding nodes as Gaussian distributions rather than point vectors, UANA enables to capture the uncertainty of a node representation, while being able to discriminate the anchor nodes from the potentially confusing neighbors. We address the P2P matching constraint by introducing an adversarial learning paradigm, which relaxes the exact matching assumption during training with an across-domain generative procedure to reduce the matching errors on testing nodes. In the end, interpretability methods are included to explain the aligning results made by our UANA based on the robust statistics, which enables the explanation of the effect of individual training sample on the NA performance without the need of retraining the model. Extensive experiments conducted on real-world data sets demonstrate that UANA significantly outperforms existing state-of-the-art baselines while providing explainable results.","Title: Popularity-Guided Cost Optimization for Live Streaming in Mobile Edge Computing\nYear: 2022\n\nAbstract: Live streaming service usually delivers the content in mobile edge computing (MEC) to reduce the network latency and save the backhaul capacity. Considering the limited resources, it is necessary that MEC servers collaborate with each other and form an overlay to realize more efficient delivery. The critical challenge is how to optimize the topology among the servers and allocate the link capacity so that the cost will be lower with delay constraints. Previous approaches rarely consider server collaborations for live streaming service, and the scheduling delay is usually ignored in MEC, leading to suboptimal performances. In this paper, we propose a popularity-guided overlay model which takes the scheduling delay into consideration and utilizes MEC collaboration to achieve efficient live streaming service. The links and servers are shared among all channel streams and each stream is pushed from cloud servers to MEC servers via the trees. Considering the optimization problem is NP-hard, we propose an effective optimization framework called cost optimization for live streaming (COLS) to predict the channel popularity by a LSTM model with multiscale input data. Finally, we compute topology graph by greedy scheme and allocate the capacity with convex programming. Experimental results show that the proposed approach achieves higher prediction accuracy, reducing the capacity cost by more than 40% with an acceptable delay compared with state-of-the-art schemes.","Title: Table Pre-training: A Survey on Model Architectures, Pre-training Objectives, and Downstream Tasks.\nYear: 2022\n\nAbstract: Since a vast number of tables can be easily collected from web pages, spreadsheets, PDFs, and various other document types, a flurry of table pretraining frameworks have been proposed following the success of text and images, and they have achieved new state-of-the-arts on various tasks such as table question answering, table type recognition, column relation classification, table search, formula prediction, etc. To fully use the supervision signals in unlabeled tables, a variety of pretraining objectives have been designed and evaluated, for example, denoising cell values, predicting numerical relationships, and implicitly executing SQLs. And to best leverage the characteristics of (semi-)structured tables, various tabular language models, particularly with specially-designed attention mechanisms, have been explored. Since tables usually appear and interact with free-form text, table pretraining usually takes the form of table-text joint pretraining, which attracts significant research interests from multiple domains. This survey aims to provide a comprehensive review of different model designs, pretraining objectives, and downstream tasks for table pretraining, and we share our thoughts and vision on existing challenges and future opportunities.","Title: Multi-scale graph capsule with influence attention for information cascades prediction\nYear: 2022\n\nAbstract: Information cascade size prediction is one of the primary challenges for understanding the diffusion of information. Traditional feature-based methods heavily rely on the quality of handcrafted features, requiring extensive domain knowledge and hard to generalize to new domains. Recently, inspired by the success of deep learning in computer vision and natural language processing, researchers have developed neural network-based approaches for tackling this problem. However, existing deep learning-based methods either focused on modeling the temporal characteristics of cascades but ignored the structural information or failed to take the order-scale and position-scale into consideration in modeling structures of information propagation. This paper proposed a novel graph neural network-based model, called MUCas, to learn the latent representations of cascade graphs from a multi-scale perspective, which can make full use of the direction-scale, high-order-scale, position-scale, and dynamic-scale of cascades via a newly designed MUlti-scale Graph Capsule Network (MUG-Caps) and the influence-attention mechanism. Extensive experiments conducted on two real-world data sets demonstrate that our MUCas significantly outperforms the state-of-the-art approaches.","Title: Detecting Abnormal Nodes in Cluster-tree Networks via the Likelihood Ratio Test of Packet Losses\nYear: 2021\n\nAbstract: While packet loss rate is a crucial indicator of network reliability, abnormal nodes dropping the transit traffic lead to higher packet loss rates. One significant challenge is to efficiently distinguish the abnormal nodes from those with normal packet losses. To address this issue, this paper presents a new detection scheme based on the Likelihood Ratio Test (LRT) for cluster-tree networks - a typical architecture of wireless networks. Due to the hierarchical structure of the networks, LRT is implemented in two phases, i.e., the local detection phase at the non-root nodes and the overall detection phase at the root node. The observed forwarding behaviors of the monitored node are modeled and quantified as log-likelihood ratios where the packet loss rate in the alternative hypothesis is a default value. In this way, the log-likelihood ratios are compared with a threshold under the maximum a posteriori probability criterion to identify the anomalies. The correctness of the proposed scheme is theoretically proved if the packet loss rate in the abnormal node exceeds a critical detection point - whose expression is also formally derived. Simulation results validate the critical detection point and demonstrate the superiority of the proposed detection scheme compared to the state-of-the-art methods.","Title: Kernel-Based Structural-Temporal Cascade Learning for Popularity Prediction\nYear: 2021\n\nAbstract: One of the main objectives of information cascade popularity prediction is to forecast the future size of a cascade given the observed propagation information. It is an enabling step for many practical applications (e.g., advertisement, academic writing, etc.). Recent advances in neural networks have spurred a few deep learning-based cascade models, which preserve the structural features of information cascades with node embedding and graph neural networks. However, efforts in cascade graph learning as well as its internal temporal dependency, existing methods mainly focus on node-level similarity learning, ignoring the structural equivalence among different sub-graphs that are more informative for information diffusion prediction. Towards this, we present a kernel-based structural-temporal cascade learning model, called CasKernel, to explicitly estimate and encode the structural similarity of cascades with the graph kernels. Moreover, we employ a non sequential process to address the temporal dependency, which can be used to facilitate information popularity prediction. Experiments conducted on both tweets propagation network and academic citation network demonstrate the effectiveness of our method.","Title: HGENA: A Hyperbolic Graph Embedding Approach for Network Alignment\nYear: 2021\n\nAbstract: Cross-network alignment aims at identifying users who participate in different social networks, which benefits a variety of downstream social applications such as precise content delivery, fraud detection, and content/user recommender systems. Recent advances in network representations and graph neural networks have spurred various network structure-based methods for capturing underlying node similarities across social networks, thereby addressing the network alignment problem. However, most of the existing solutions rely on embedding methods that compute node similarity in Euclidean space, resulting in severe distortion or semantic loss when representing real-world social networks, which are usually scale free and with hierarchical structures. We address these issues by presenting a novel model: Hyperbolic Graph Embedding for Network Alignment (HGENA), which learns the structural semantics more efficiently by embedding nodes in hyperbolic space instead of Euclidean. HGENA overcomes the scalability issue since it requires far fewer dimensions in Riemannian manifolds and increases the capability of learning hierarchical structures, while enabling smaller distortion for tree-liked networks to facilitate node alignment. We also introduce alternative network mapping functions to compute node similarity across-network based on its distance on the Poincare ball. Experimental evaluations conducted on real world datasets demonstrate that HGENA achieves superior performance on social network alignment, especially for more tree-liked networks.","Title: Multi-Objective Distributional Reinforcement Learning for Large-Scale Order Dispatching\nYear: 2021\n\nAbstract: The aim of this paper is to develop a multi-objective distributional reinforcement learning framework for improving order dispatching on large-scale ride-hailing platforms. Compared with traditional RL-based approaches that focus on drivers' income, the proposed framework also accounts for the spatiotemporal difference between the supply and demand networks. Specifically, we model the dispatching problem as a two-objective Semi-Markov Decision Process (SMDP) and estimate the relative importance of the two objectives under some unknown existing policy via Inverse Reinforcement Learning (IRL). Then, we combine Implicit Quantile Networks (IQN) with the traditional Deep Q-Networks (DQN) to jointly learn the two return distributions and adjusting their weights to refine the old policy through on-line planning and achieve a higher supply-demand coherence of the platform. We conduct large-scale dispatching experiments to demonstrate the remarkable improvement of proposed approach on the platform's efficiency.","Title: Dynamic Manifold Learning for Land Deformation Forecasting.\nYear: 2022\n\nAbstract: Landslides refer to occurrences of massive ground movements due to geological (and meteorological) factors, and can have disastrous impact on property, economy, and even lead to loss of life. The advances of remote sensing provide accurate and continuous terrain monitoring, enabling the study and analysis of land deformation which, in turn, can be used for possible landslides forecast. Prior studies either rely on independent observations for displacement prediction or model static land characteristics without considering the subtle interactions between different locations and the dynamic changes of the surface conditions. We present DyLand -- Dynamic Manifold Learning with Normalizing Flows for Land deformation prediction -- a novel framework for learning dynamic structures of terrain surface and improving the performance of land deformation prediction. DyLand models the spatial connections of InSAR measurements and estimates conditional distributions of deformations on the terrain manifold with a novel normalizing flow-based method. Instead of modeling the stable terrains, it incorporates surface permutations and captures the innate dynamics of the land surface while allowing for tractable likelihood estimates on the manifold. Our extensive evaluations on curated InSAR datasets from continuous monitoring of slopes prone to landslides show that DyLand outperforms existing bechmarking models.","Title: PrEF: Probabilistic Electricity Forecasting via Copula-Augmented State Space Model.\nYear: 2022\n\nAbstract: Electricity forecasting has important implications for the key decisions in modern electricity systems, ranging from power generation, transmission, distribution and so on. In the literature, traditional statistic approaches, machine-learning methods and deep learning (e.g., recurrent neural network) based models are utilized to model the trends and patterns in electricity time-series data. However, they are restricted either by their deterministic forms or by independence in probabilistic assumptions -- thereby neglecting the uncertainty or significant correlations between distributions of electricity data. Ignoring these, in turn, may yield error accumulation, especially when relying on historical data and aiming at multi-step prediction. To overcome these, we propose a novel method named Probabilistic Electricity Forecasting (PrEF) by proposing a non-linear neural state space model (SSM) and incorporating copula-augmented mechanism into that, which can learn uncertainty-dependencies knowledge and understand interactive relationships between various factors from large-scale electricity time-series data. Our method distinguishes itself from existing models by its traceable inference procedure and its capability of providing high-quality probabilistic distribution predictions. Extensive experiments on two real-world electricity datasets demonstrate that our method consistently outperforms the alternatives.","Title: A Probabilistic Framework for Land Deformation Prediction (Student Abstract).\nYear: 2022\n\nAbstract: The development of InSAR (satellite Interferometric Synthetic Aperture Radar) enables accurate monitoring of land surface deformations, and has led to advances of deformation forecast for preventing landslide, which is one of the severe geological disasters. Despite the unparalleled success, existing spatio-temporal models typically make predictions on static adjacency relationships, simplifying the conditional dependencies and neglecting the distributions of variables. To overcome those limitations, we propose a Distribution Aware Probabilistic Framework (DAPF), which learns manifold embeddings while maintaining the distribution of deformations. We obtain a dynamic adjacency matrix upon which we approximate the true posterior while emphasizing the spatio-temporal characteristics. Experimental results on real-world dataset validate the superior performance of our method.","Title: Learning Contrastive Multi-View Graphs for Recommendation (Student Abstract).\nYear: 2022\n\nAbstract: This paper exploits self-supervised learning (SSL) to learn more accurate and robust representations from the user-item interaction graph. Particularly, we propose a novel SSL model that effectively leverages contrastive multi-view learning and pseudo-siamese network to construct a pre-training and post-training framework. Moreover, we present three graph augmentation techniques during the pre-training stage and explore the effects of combining different augmentations, which allow us to learn general and robust representations for the GNN-based recommendation. Simple experimental evaluations on real-world datasets show that the proposed solution significantly improves the recommendation accuracy, especially for sparse data, and is also noise resistant.","Title: Linking Transformer to Hawkes Process for Information Cascade Prediction (Student Abstract).\nYear: 2022\n\nAbstract: Information cascade is typically formalized as a process of (simplified) discrete sequence of events, and recent approaches have tackled its prediction via variants of recurrent neural networks. However, the information diffusion process is essentially an evolving directed acyclic graph (DAG) in the continuous-time domain. In this paper, we propose a transformer enhanced Hawkes process (Hawkesformer), which links the hierarchical attention mechanism with Hawkes process to model the arrival stream of discrete events continuously. A two-level attention architecture is used to parameterize the intensity function of Hawkesformer, which captures the long-term dependencies between nodes in graph and better embeds the cascade evolution rate for modeling short-term outbreaks. Experimental results demonstrate the significant improvements of Hawkesformer over the state-of-the-art.","Title: Large-Scale IP Usage Identification via Deep Ensemble Learning (Student Abstract).\nYear: 2022\n\nAbstract: Understanding users' behavior via IP addresses is essential towards numerous practical IP-based applications such as online content delivery, fraud prevention, and many others. Among which profiling IP address has been extensively studied, such as IP geolocation and anomaly detection. However, less is known about the scenario of an IP address, e.g., dedicated enterprise network or home broadband. In this work, we initiate the first attempt to address a large-scale IP scenario prediction problem. Specifically, we collect IP scenario data from four regions and propose a novel deep ensemble learning-based model to learn IP assignment rules and complex feature interactions. Extensive experiments support that our method can make accurate IP scenario identification and generalize from data in one region to another.","Title: Conditional Collaborative Filtering Process for Top-K Recommender System (Student Abstract).\nYear: 2022\n\nAbstract: Conditional neural process (CNP) has been extensively applied into data analyzing tasks due to its excellent ability to make accurate predictions for incomplete data points. However, in literature there are only few works that studied the CNPin recommendation systems. In this work, we propose CCFP, which is a collaborative filtering method that differs from other CF models by incorporating CNP into encoder-decoder architecture. By analyzing the complete user-item interaction data, our model fits a global representation that can better rep-resenting the features of users and items. CCFP can significantly improve the recommendation performance compared to baselines by predicting items for the target users with their incomplete observation data.","Title: Fine-Grained Urban Flow Inference via Normalizing Flow (Student Abstract).\nYear: 2022\n\nAbstract: Fine-grained urban flow inference (FUFI) aims to infer the coarse-grained (CG) urban flow map to the corresponding fine-grained (FG) one, which plays an important role in efficient traffic monitoring and management in smart cities. In FUFI, the CG map can be obtained with only a small number of monitoring devices, greatly reducing the overhead of deploying devices and the costs of maintenance, labor, and electricity. Existing FUFI methods are mainly based on techniques from image super-resolution (SR) models, which cannot fully consider the influence of external factors and face the ill-posed problem in SR tasks. In this paper, we propose UFI-Flow, a novel approach for addressing the FUFI problem by learning the conditional distributions of CG and FG map pairs. Given the CG map and the latent variables, the corresponding FG map is inferred by invertible transformations. In addition, an augmented distribution fusion mechanism is further proposed to constrain the urban flow distribution within the influence of external factors. We provide a new large-scale real-world FUFI dataset and show that UFI-Flow significantly outperforms the strong baselines.","Title: Heterogeneous dynamical academic network for learning scientific impact propagation\nYear: 2022\n\nAbstract: Quantifying and predicting the long-term impact of both scientific papers and individual authors have important implications for many academic policy decisions, from identifying emerging trends to assessing the merits of proposals for potential funding. This paper presents SI-HDGNN, a novel heterogeneous dynamical graph neural network that explicitly models a heterogeneous, weighted, directed and attributed academic graph, enabling a prediction of the cumulative scientific impact of papers and authors by a specifically designed aggregation method. Unlike the existing feature-based or homogeneous approaches, SI-HDGNN addresses the problem by capturing the temporal–structural characteristics of the papers and authors as well as their complex interactions and long-term dependencies. Extensive experiments conducted on three large-scale multidisciplinary academic datasets demonstrate its superior performance in predicting the long-term scientific impact of both scientific papers and authors.","Title: Identifying user geolocation with Hierarchical Graph Neural Networks and explainable fusion\nYear: 2022\n\nAbstract: Determining user geolocation from social media data is essential in various location-based applications — from improved transportation/supply management, through providing personalized services and targeted marketing, to better overall user experiences. Previous methods rely on the similarity of user posting content and neighboring nodes for user geolocation, which suffer the problems of: (1) position-agnostic of network representation learning, which impedes the performance of their prediction accuracy; and (2) noisy and unstable user relation fusion due to the flat graph embedding methods employed. This work presents Hierarchical Graph Neural Networks (HGNN) – a novel methodology for location-aware collaborative user-aspect data fusion and location prediction. It incorporates geographical location information of users and clustering effect of regions and can capture topological relations while preserving their relative positions. By encoding the structure and features of regions with hierarchical graph learning, HGNN can primarily alleviate the problem of noisy and unstable signal fusion. We further design a relation mechanism to bridge connections between individual users and clusters, which not only leverages the information of isolated nodes that are useless in previous methods but also captures the relations between unlabeled nodes and labeled subgraphs. Furthermore, we introduce a robust statistics method to interpret the behavior of our model by identifying the importance of data samples when predicting the locations of the users. It provides meaningful explanations on the model behaviors and outputs, overcoming the drawbacks of previous approaches that treat user geolocation as “black-box” modeling and lacking interpretability. Comprehensive evaluations on real-world Twitter datasets verify the proposed model’s superior performance and its ability to interpret the user geolocation results.","Title: Multi-view learning with distinguishable feature fusion for rumor detection\nYear: 2022\n\nAbstract: Researchers, enterprises, and governments have made great efforts to detect misinformation promptly and accurately. Traditional solutions either examine complicated hand-crafted features or rely heavily on the constructed credibility networks to extract useful indicators for discerning false information. However, such approaches require insightful domain expert knowledge and intensive feature engineering that are often non-generalizable. Recent advances in deep learning techniques have spurred learning high-level representations from textual and image content and discovering diffusion patterns with various neural networks. Despite the progress made by these methods, they still face the problem of overdependence on the content features and fail to discriminate against the influence of each user involved in the process of rumor spreading. Different user-aspect information plays different roles in various stages of rumor diffusion, effectively extract features from each aspect, and aggregate the learned features into a unique representation, which has not been well investigated. To address these limitations, we propose a novel model, UMLARD (User-aspect Multi-view Learning with Attention for Rumor Detection), to effectively learn the representation of different views of the users who engaged in spreading the tweet, and fuse the learned features through the distinguishable fusion mechanism. Finally, we concatenate the learned user-aspect features with content features to form a unique representation and feed it into a fully connected layer to predict the label of rumors. Our experiments conducted on real-world datasets demonstrate that UMLARD significantly improves the rumor detection performance compared to state-of-the-art baselines. It also allows explainability of the model behavior and the predicted results.","Title: Social-trust-aware variational recommendation\nYear: 2022\n\nAbstract: Most existing studies that employ social-trust information to solve the data sparsity issue in recommender systems assume that socially connected users have equal influence on each other. However, this assumption does not hold in practice since users and their friends may not have similar interests because social connections are multifaceted and exhibit heterogeneous strengths in different scenarios. Therefore, estimating the diverse levels of influence among entities (users/items/social connections) is very important in advancing social recommender systems. Towards this goal, we propose a new model named Social-Trust-Aware Variational Recommendation (SOAP-VAE). Particularly, SOAP-VAE leverages graph attention network techniques to capture the varying levels of influence and the complex interaction patterns among all the entities collectively and holistically. In doing so, heterogeneity among entities is obtained seamlessly. Consequently, we generate social-trust-aware item embedding representations in which the right level of influence has been integrated. Next, based on these rich social-trust-aware item representations, we formulate the first-ever social-trust-aware prior in literature. Unlike priors utilized in earlier VAE-based recommendation models, this novel prior aids in dealing with the issue of posterior-collapse and can effectively capture the uncertainty of latent space. In effect, the model produces better latent representations, which significantly alleviates the data sparsity issue. Finally, we empirically show that SOAP-VAE outperforms several state-of-the-art baselines on three real-world data sets.","Title: SNPD: Semi-Supervised Neural Process Dehazing Network with Asymmetry Pseudo Labels\nYear: 2022\n\nAbstract: Haze can cause a significant reduction in the contrast and brightness of images. CNN-based methods have achieved benign performance on synthetic data. However, they show weak generalization performance on real data because they are only trained on fully labeled data, ignoring the role of natural data in the network. That is, there exists distribution shift. In addition to using little real data for training image dehazing networks in the literature, few studies have designed losses to constrain the intermediate latent space and the output simultaneously. This paper presents a semi-supervised neural process dehazing network with asymmetry pseudo labels. First, we use labeled data to train a backbone network and save intermediate latent features and parameters. Then, in the latent space, the neural process maps the latent features of real data to the latent space of synthetic data to generate one pseudo label. One neural process loss is proposed here. For situations where the image may be darker after dehazing, another pseudo label is created, and one new loss is used to guide the dehazing result at the output end. We combine the two pseudo labels with designed losses to suppress the distribution shift and guide better dehazing results. Finally, the artificial and hazy natural images are tested experimentally to demonstrate the method's effectiveness.","Title: Landslide Displacement Prediction via Attentive Graph Neural Network\nYear: 2022\n\nAbstract: Landslides are among the most common geological hazards that result in considerable human and economic losses globally. Researchers have put great efforts into addressing the landslide prediction problem for decades. Previous methods either focus on analyzing the landslide inventory maps obtained from aerial photography and satellite images or propose machine learning models-trained on historical land deformation data-to predict future displacement and sedimentation. However, existing approaches generally fail to capture complex spatial deformations and their inter-dependencies in different areas. This work presents a novel landslide prediction model based on graph neural networks, which utilizes graph convolutions to aggregate spatial correlations among different monitored locations. Besides, we introduce a novel locally historical transformer network to capture dynamic spatio-temporal relations and predict the surface deformation. We conduct extensive experiments on real-world data and demonstrate that our model significantly outperforms state-of-the-art approaches in terms of prediction accuracy and model interpretations.","Title: Multi-receptive Field Aggregation Network for single image deraining\nYear: 2022\n\nAbstract: Image deraining is a significant problem that ensures the visual quality of images to prompt computer vision systems. However, due to the insufficiency of captured rain streaks features and global information, current image deraining methods often face the issues of rain streaks remaining and image blurring. In this paper, we propose a Multi-receptive Field Aggregation Network (MRFAN) to restore a cleaner rain-free image. Specifically, we construct a Multi-receptive Field Feature Extraction Block (MFEB) to capture rain features with different receptive fields. In MFEB, we design a Self-supervised Block (SSB) and an Aggregation Block (AGB). SSB can make the network adaptively focus on the critical rain features and rain-covered areas. AGB effectively aggregates and redistributes the multi-scale features to help the network simulate rain streaks better. Experiments show that our method achieves better results on both synthetic datasets and real-world rainy images.","Title: Test-Driven Feature Extraction of Web Components\nYear: 2022\n\nAbstract: With the growing requirements of web applications, web components are developed to package the implementation of commonly-used features for reuse. In some cases, the developer may want to reuse some features which cannot be customized by the component's APIs. He/she has to extract the implementation by hand. It is labor-intensive and error-prone. Considering the widely-used test cases which can be useful to specify the software features, a test-driven approach is proposed to extract the implementation of the desired features in web components. The satisfaction of the user's requirements is transformed into the passing rate of user-specified test cases. In this way, the quality of the extraction result can be evaluated automatically. Meanwhile, a record/replay-based GUI test generation method is proposed to ensure that the extraction result has the correct GUI appearance. To extract the feature implementation, a hierarchical genetic algorithm is proposed to find the code snippet that can pass all the tests and has the approximate smallest size. We compare our method with two existing feature extraction methods. The result shows that our method can extract the correct implementation with the minimum size. A human-subject study is conducted to show the effectiveness and weaknesses of our method in helping users extract the features.","Title: Variational cold-start resistant recommendation\nYear: 2022\n\nAbstract: Conventionally, cold-start limitations are managed by leveraging side information such as social-trust relationships. However, the relationships between users in social networks are complex, uncertain, and sparse. Therefore, it is necessary to extract beneficial social connections to make the recommendation models cold-start resistant. Towards this end, we propose a novel recommendation model called Variational Cold-start Resistant Recommendation (CORE-VAE). More concretely, we employ a social-aware similarity function and a graph convolutional network (GCN) to generate robust social-aware user representations that account for the complexities, uncertainties, and sparse nature of the social-trust network. Subsequently, these powerful social-aware representations aid us in producing cold-start resistant rating vectors for all users. To explore the rich user rating information, we propose an expressive variational autoencoder (VAE) model. Unlike earlier VAE-based CF models, CORE-VAE utilizes a novel prior distribution and a well-designed skip-generative network to alleviate the posterior collapse issue considerably. Besides, CORE-VAE can also capture the latent space’s uncertainty and ensure that observations and their accompanying latent variables have high mutual information. Overall, these novel techniques dramatically help produce better latent representations for generating more accurate recommendations. We show that CORE-VAE outperforms numerous competitive baseline models on real-world datasets through comprehensive empirical evaluation and analysis.","Title: Quantification and Analysis of Layer-wise and Pixel-wise Information Discarding.\nYear: 2022\n\nAbstract: This paper presents a method to explain how the information of each input variable is gradually discarded during the forward propagation in a deep neural network (DNN), which provides new perspectives to explain DNNs. We define two types of entropy-based metrics, i.e. (1) the discarding of pixel-wise information used in the forward propagation, and (2) the uncertainty of the input reconstruction, to measure input information contained by a specific layer from two perspectives. Unlike previous attribution metrics, the proposed metrics ensure the fairness of comparisons between different layers of different DNNs. We can use these metrics to analyze the efficiency of information processing in DNNs, which exhibits strong connections to the performance of DNNs. We analyze information discarding in a pixel-wise manner, which is different from the information bottleneck theory measuring feature information w.r.t. the sample distribution. Experiments have shown the effectiveness of our metrics in analyzing classic DNNs and explaining existing deep-learning techniques. The code is available at https://github.com/haotianSustc/deepinfo.","Title: Combination Complex-Valued Bayesian Compressive Sensing Method for Sparsity Constrained Deconvolution Beamforming\nYear: 2022\n\nAbstract: Several deconvolution methods have been proposed to reduce the mainlobe width and sidelobe intensity of conventional beamforming results without increasing the array aperture; however, most of them cannot perform well in the face of coherent targets. Therefore, it is discerning to deconvolve the complex-valued beamforming result rather than the beamforming intensity. However, conventional deconvolution methods focus on the beam intensity, and only a few studies have investigated complex-valued deconvolution beamforming (CDB). Considering the sparse property of the targets in practice, the CDB can be converted to a complex-valued inverse compressive sensing problem and put into the Bayesian framework. To solve it efficiently, a complex-valued relevance-vector-machine (RVM) tool is used to build the complex-valued Bayesian compressive sensing (C-BCS) method that has excellent performance in terms of recovery accuracy and operating speed. However, the C-BCS method is not stable for the CDB because the point spread function is a rank deficiency matrix. To overcome this problem, we propose the combination C-BCS method that combines the block-sparse and C-BCS methods to improve the performance of solving the CDB. The simulation results proved that the proposed method performed better than intensity-based deconvolution methods for the beamforming results generated by the coherent targets. A beamforming image of a pool scene captured by a narrowband forward-looking sonar system was adopted to test various deconvolution methods, and the proposed method exhibited superiority in sidelobe suppression.","Title: Generating Personas for Products on Social Media: A Mixed Method to Analyze Online Users\nYear: 2022\n\nAbstract: The purpose of this research is to develop a methodology that combines the quantitative and the qualitative analysis to generate personas for products on social platforms. The user data on social platforms contain massive information relating to the lifestyle people have and the products people use or are interested. By analyzing the specific content generated by users on social platforms, e.g., content involving the term \"tablet,\" it is possible to reveal how the users consider or use the product, \"tablet.\" By analyzing the users' homepages, the information relating to the users' daily life can be found. We collected 276, 675 pieces of relevant data regarding the product, \"tablet,\" from 12, 965 online users on China's widely used social media platforms. Then automatic user segments and the profiles of each group were generated and structured by natural language processing technology. The results of these quantitative analyses were then qualitatively examined by manual analyses, which provide additional insights and detailed descriptions on the automatically generated persona profiles. In this study, six personas representing distinct user types were created. The mixed method of combining the quantitative and qualitative methods makes the generation of personas faster and more insightful. The generated personas can represent real user behavior and characteristics and can provide insights into the products, which also can provide support on designing new products and optimizing existing products.","Title: Contextual spatio-temporal graph representation learning for reinforced human mobility mining\nYear: 2022\n\nAbstract: The rapid development of location-based services spurred a large number of user-centric applications. Particularly, an interesting topic has attracted the attention of researchers that is to link trajectories to users (TUL). Despite the significant progress made by recent deep learning-based human mobility learning models, tackling TUL problem is still challenging. In this paper, we propose a novel reinforced trajectory learning approach called GraphTUL that implements an adversarial network with the policy gradient to improve the identification ability and leverages both labeled and unlabeled trajectories to address the insufficient label issue in a semi-supervised manner. Besides, some critical factors related to personal context and indispensable elements in current mobility learning models are still missing. Thus, we propose a novel graph-based human motion representation model (CGE) to exploit the contextual information from users’ trajectories for alleviating data sparsity and contextual constraint issues. CGE builds a unified graph with historical check-ins to reflect users’ geographical preferences and visiting intentions. It allows us to sample synthetic but realistic trajectories for augmenting data and enhancing contextual check-in embedding. We also successfully apply it to next check-in prediction task. The experimental results conducted on several real-world datasets demonstrate that our proposed method achieves significantly better performance than the state-of-the-art baselines.","Title: Temporally Multi-Modal Semantic Reasoning with Spatial Language Constraints for Video Question Answering\nYear: 2022\n\nAbstract: Video question answering (QA) aims to understand the video scene and underlying plot by answering video questions. An algorithm that can competently cope with this task needs to be able to: (1) collect multi-modal information scattered in the video frame sequence while extracting, interpreting, and utilizing the potential semantic clues provided by each piece of modal information in the video, (2) integrate the multi-modal context of the above semantic clues and understand the cause and effect of the story as it evolves, and (3) identify and integrate those temporally adjacent or non-adjacent effective semantic clues implied in the above context information to provide reasonable and sufficient visual semantic information for the final question reasoning. In response to the above requirements, a novel temporally multi-modal semantic reasoning with spatial language constraints video QA solution is reported in this paper, which includes a significant feature extraction module used to extract multi-modal features according to a significant sampling strategy, a spatial language constraints module used to recognize and reason spatial dimensions in video frames under the guidance of questions, and a temporal language interaction module used to locate the temporal dimension semantic clues of the appearance features and motion features sequence. Specifically, for a question, the result processed by the spatial language constraints module is to obtain visual clues related to the question from a single image and filter out unwanted spatial information. Further, the temporal language interaction module symmetrically integrates visual clues of the appearance information and motion information scattered throughout the temporal dimensions, obtains the temporally adjacent or non-adjacent effective semantic clue, and filters out irrelevant or detrimental context information. The proposed video QA solution is validated on several video QA benchmarks. Comprehensive ablation experiments have confirmed that modeling the significant video information can improve QA ability. The spatial language constraints module and temporal language interaction module can better collect and summarize visual semantic clues.","Title: A seizure detection method based on hypergraph features and machine learning\nYear: 2022\n\nAbstract: Effective feature extraction is the key to successful seizure detection. A good feature should be adaptable, noise resistant, and informative. In this study, a seizure detection method based on hypergraph features and machine learning was proposed. During the preprocessing step, the magnitude-squared coherence (MSC) method was used to select the useful channels and frequency band. The hypergraph method was introduced to represent the correlation network based on the MSC result. Hypergraphs can show relationships between channels, and they have higher dimensional properties than normal graphs. To quantify the characteristics of these channels, three feature coefficients, which are HG-Independent(HG-Ind), HG-Dependent(HG-Dep), and HG-Share(HG-Sha), were derived and input as features into the machine learning algorithm. Two machine learning algorithms, random forest (RF) and support vector machine (SVM), were tested on the data of eight patients in our study. According to the results, RF had a better performance than SVM, and the group of three features performed better than the single feature. Three additional methods from other papers, extra-trees, random forest based on spectral correlation, and neural networks, were compared with the HG-RF, and the HG-RF had the best performance, with an accuracy of 96.30%. This method showed resistance to noise and adaptability for different patient data. In addition, this method facilitated a balance between effectiveness and efficiency and provided a new idea for online detection of epilepsy.","Title: Double-Check Soft Teacher for Semi-Supervised Object Detection.\nYear: 2022\n\nAbstract: In the semi-supervised object detection task, due to the scarcity of labeled data and the diversity and complexity of objects to be detected, the quality of pseudo-labels generated by existing methods for unlabeled data is relatively low, which severely restricts the performance of semi-supervised object detection. In this paper, we revisit the pseudo-labeling based Teacher-Student mutual learning framework for semi-supervised object detection and identify that the inconsistency of the location and feature of the candidate object proposals between the Teacher and the Student branches are the fatal cause of the low quality of the pseudo labels. To address this issue, we propose a simple yet effective technique within the mainstream teacher-student framework, called Double Check Soft Teacher, to overcome the harm caused by insufficient quality of pseudo labels. Specifically, our proposed method leverages teacher model to generate pseudo labels for the student model. Especially, the candidate boxes generated by the student model based on the pseudo label will be sent to the teacher model for \"double check\", and then the teacher model will output probabilistic soft label with background class for those candidate boxes, which will be used to train the student model. Together with a pseudo labeling mechanism based on the sum of the TOP-K prediction score, which improves the recall rate of pseudo labels, Double Check Soft Teacher consistently surpasses state-of-the-art methods by significant margins on the MS-COCO benchmark, pushing the new state-of-the-art. Source codes are available at https://github.com/wkfdb/DCST.","Title: Identifying IP Usage Scenarios: Problems, Data, and Benchmarks\nYear: 2022\n\nAbstract: Given an IP address, understanding its initial assignment,and predicting its potential usage can significantly help toward improving efficiency of many practical IP-based applications, such as Ad-recommendation, point of interest selection, fraud detection, and Internet service optimization. However, there are only a few prior studies conducted on predicting IP usage from its assignment. Surprisingly, there does not exist a benchmark dataset available to academia that can be used to investigate and develop IP usage predictions for different IP applications. In this work, we formulate the IP usage prediction problem; specifically, we collect large-scale, real-world data and extract salient features using sophisticated networking tools such as different network signals, trace route delay, IP block usage, and geographical landmarks. We showcase a series of tabular information retrieval methods to learn network signals and their interactions, and identify the IP usage scenarios. We believe our datasets and algorithms can benefit the community to facilitate relevant research in this domain, yielding more efficient and effective solutions to multiple categories of applications.","Title: MDP2 Forest: A Constrained Continuous Multi-dimensional Policy Optimization Approach for Short-video Recommendation\nYear: 2022\n\nAbstract: In the ecology of short video platforms, the optimal exposure proportion of each video category is crucial to guide recommendation systems and content production in a macroscopic way. Though extensive studies on recommendation systems are devoted to providing the most well-matched videos for each view request, fitting the data without considering inherent biases such as selection bias and exposure bias will result in serious issues. In this paper, we formalize the exposure proportion strategy as a policy-making problem with multi-dimensional continuous treatment under certain constraints from a causal inference point of view. We propose a novel ensemble policy learning method based on causal trees, called Maximum Difference of Preference Point Forest (MDP2 Forest), which overcomes the shortcomings of existing policy learning approaches. Experimental results on both simulated and synthetic datasets show the superiority of our algorithm compared to other policy learning or causal inference methods in terms of the treatment estimation accuracy and the mean regret. Furthermore, the proposed MDP2 Forest method can also adapt to a wide range of business settings such as imposing different kinds of constraints on the multi-dimensional treatment.","Title: Connecting the Hosts: Street-Level IP Geolocation with Graph Neural Networks\nYear: 2022\n\nAbstract: Pinpointing the geographic location of an IP address is important for a range of location-aware applications spanning from targeted advertising to fraud prevention. The majority of traditional measurement-based and recent learning-based methods either focus on the efficient employment of topology or utilize data mining to find clues of the target IP in publicly available sources. Motivated by the limitations in existing works, we propose a novel framework named GraphGeo, which provides a complete processing methodology for street-level IP geolocation with the application of graph neural networks. It incorporates IP hosts knowledge and kinds of neighborhood relationships into the graph to infer spatial topology for high-quality geolocation prediction. We explicitly consider and alleviate the negative impact of uncertainty caused by network jitter and congestion, which are pervasive in complicated network environments. Extensive evaluations across three large-scale real-world datasets demonstrate that GraphGeo significantly reduces the geolocation errors compared to the state-of-the-art methods. Moreover, the proposed framework has been deployed on the web platform as an online service for 6 months.","Title: Mining Spatio-Temporal Relations via Self-Paced Graph Contrastive Learning\nYear: 2022\n\nAbstract: Modeling complex spatial and temporal dependencies are indispensable for location-bound time series learning. Existing methods, typically relying on graph neural networks (GNNs) and temporal learning modules based on recurrent neural networks, have achieved significant performance improvements. However, their representation capabilities and prediction results are limited when pre-defined graphs are unavailable. Unlike spatio-temporal GNNs focusing on designing complex architectures, we propose a novel adaptive graph construction strategy: Self-Paced Graph Contrastive Learning (SPGCL). It learns informative relations by maximizing the distinguishing margin between positive and negative neighbors and generates an optimal graph with a self-paced strategy. Specifically, the existing neighborhoods iteratively absorb more reliable nodes with the highest affinity scores as new neighbors to generate the next-round neighborhoods, and augmentations are applied to improve the transferability and robustness. As the adaptively self-paced graph approaches the optimized graph for prediction, the mutual information between nodes and the corresponding neighbors is maximized. Our work provides a new perspective of addressing spatio-temporal learning problems beyond information aggregation in Euclidean space and can be generalized to different tasks. Extensive experiments conducted on two typical spatio-temporal learning tasks (traffic forecasting and land displacement prediction) demonstrate the superior performance of SPGCL against the state-of-the-art.","Title: A New Abnormal Node Detection Method With Dynamic Hoeffding Test\nYear: 2022\n\nAbstract: In this letter, we propose a new method based on the dynamic Hoeffding test that can distinguish the abnormal relay nodes from those with normal packet loss in wireless communications. An asymptotic analysis of the detection performance on the Hoeffding test is conducted to determine the new dynamic detection threshold for decreasing the total probability of errors. With the theoretical guarantees, both false alarm and missed detection probabilities of the proposed scheme converge \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">exponentially</i>\n as the number of detection periods increases. Simulation results validate our analysis and demonstrate the superior detection performance of the proposed method.","Title: Exploring Image Regions Not Well Encoded by an INN\nYear: 2022\n\nAbstract: This paper proposes a method to clarify image regions that are not well encoded by an invertible neural network (INN), i.e. image regions that significantly decrease the likelihood of the input image. The proposed method can diagnose the limitation of the representation capacity of an INN. Given an input image, our method extracts image regions, which are not well encoded, by maximizing the likelihood of the image. We explicitly model the distribution of not-well-encoded regions. A metric is proposed to evaluate the extraction of the not-well-encoded regions. Finally, we use the proposed method to analyze several state-of-the-art INNs trained on various benchmark datasets.","Title: HydroFlow: Towards probabilistic electricity demand prediction using variational autoregressive models and normalizing flows\nYear: 2022\n\nAbstract: We present HydroFlow, a novel deep generative model for predicting the electricity generation demand of large-scale hydropower stations. HydroFlow uses a latent stochastic recurrent neural network to capture the dependencies in the multivariate time series. It not only utilizes the hidden state of the neural network, but also considers the uncertainty of variables related to natural and social factors. We also introduce an end-to-end approach based on generative flows to approximate the posterior distribution of time series with exact likelihoods. Our model is powerful as adding stochasticity to different factors (e.g., reservoir capacity and water-flow measurements) and thus overcomes the expressiveness limitations of deterministic prediction methods. It also enables trainable latent transformations that can improve the model interpretability. We evaluate HydroFlow on the data collected from the hydropower stations of a large-scale hydropower development company. Experimental results show that our model significantly outperforms the state-of-the-art baseline methods while providing explainable results.","Title: Transformer-enhanced Hawkes process with decoupling training for information cascade prediction\nYear: 2022\n\nAbstract: The ability to model the information diffusion process and predict its size is crucial to understanding information propagation mechanism and is useful for many applications such as popularity prediction and fake news detection. Recent research works have attempted to address the problem of information cascade prediction using two basic paradigms: (1) sequential methods, e.g., recurrent neural networks (RNNs), and (2) graph learning techniques to retain the topological information and enable consideration of structural relationships among diffusion participants. However, existing models consider the topological and temporal features separately, falling short of simulating their entanglement in the diffusion process. As a consequence, since the evolving directed acyclic graph (DAG) of information diffusion is intrinsically coupled with both topological and temporal dependencies, there is a loss of cross-domain information. In this paper, we propose a transformer enhanced Hawkes process (Hawkesformer), which links the hierarchical attention mechanism to Hawkes self-exciting point process for information cascade prediction. Specifically, we extend traditional Hawkes process with a topological horizon and efficiently acquire knowledge from continuous-time domain. A two-level attention architecture is used to parameterize the intensity function of Hawkesformer. At the first-level, we disentangle the primary and non-primary paths to simulate the coupled topological and temporal information for capturing the global dependencies between the nodes in a graph. At the second-level, a local pooling attentive module is proposed to embed the cascade evolution rate for modeling short-term outbreaks. Extensive experiments on two real-world datasets demonstrate the significant performance improvements of Hawkesformer over existing state-of-the-art models.","Title: A probabilistic multi-criteria evaluation framework for integrated energy system planning\nYear: 2022\n\nAbstract: For the planning of integrated energy system (IES), it is of great significance to accurately evaluate the performance of the system’s energy supply in a number of aspects including e.g., economy, operational efficiency, environmental effects and security. In order to address the difficulties associated with uncertainties of evaluation indices, one probabilistic multi-criteria evaluation (PMCE) framework is proposed in this study for a class of integrated energy supply systems. In this framework, the evaluation is carried out based on probability distributions instead of deterministic values of evaluation indices, and to determine the criterion weights in PMCE, a Dirichlet mixture model (DMM) is applied to determine the weights required in PMCE to represent the priorities of different criteria. A case study has been carried out to evaluate the overall performce of five energy supply systems with a smart community demonstrative project. The results show that the proposed approach outperforms existing average-based and maximum entropy principle (MEP)-based approaches and demonstrate good robustness when encountering changes in the prices of electricity and natural gas.","Title: Unsupervised Domain Adaptation Image Dehazing with Contrastive Nearest-Farthest Subspace Distance\nYear: 2022\n\nAbstract: Haze can cause significant changes in the data domain of the image. Due to domain-shift problem, the model trained on the synthetic haze images has a weak or even invalid dehazing ef-fect on the real data. This paper proposes an unsupervised domain adaptation dehazing method based on the nearest-farthest subspace distance in response to this problem. For the middle convolved features, the matrix singular value de-composition is used to obtain the basis vectors of the support subspace. Narrowing the angle between the basis vectors of natural and synthetic haze domains could reduce the differ-ence between the data domains. In subspace, a newly defined distance with a new penalty term named subspace measure distance is employed to constrain the model. Furthermore, to avoid search blindness of the proposed method in the real data training phase, we propose the nearest-farthest subspace distance inspired by contrastive learning. In addition, we use a new training strategy. Finally, the experimental tests on the synthetic and real images prove the effectiveness of the pro-posed method.","Title: Integrating Heterogeneous Sources for Learned Prediction of Vehicular Data Consumption\nYear: 2022\n\nAbstract: In addition to the multiple sensors to measure parameters that can be used to improve both safety and efficiency, modern vehicles also gather information about external data (e.g., traffic conditions, weather) which, if properly used, could further improve the overall trip experience. Specifically, when it comes to navigation, one source that can provide increased context awareness, especially for autonomous driving, are the High Definition (HD) maps, which have recently witnessed a tremendous growth of popularity in vehicular technology and use. As they are limited to a particular geographic area, different portions need to be downloaded (and processed) on multiple occasions throughout a given trip, along with the other data from other internal and external sources. In this paper, we provide an effective deep learning approach for the recently introduced problem of Predicting Map Data Consumption (PMDC) in the future time instants for a given trip. We propose a novel methodology that integrates multiple data sources (road network, traffic, historic trips, HD maps) and, for a given trip, enables prediction of the map data consumption. Our experimental observations demonstrate the benefits of the proposed approach over the candidate baselines."],"string":"[\n \"Title: Motion Trends Detection in Wireless Sensor Networks\\nYear: 2012\\n\\nAbstract: We address the problem of efficient detection of destination-related motion trends in Wireless Sensor Networks (WSN) where tracking is done in collaborative manner among the sensor nodes participating in location detection. In addition to determining a single location, applications may need to detect whether certain properties are true for the (portion of the) entire trajectories. Transmitting the sequence of (location, time) values to a dedicated sink and relying on the sink to detect the validity of the desired properties is a brute-force approach that generates a lot of communication overhead. We present an in-network distributed algorithm for efficient detecting of the Continuously Moving Towards predicate with respect to a given destination that is either a point or a region with polygonal boundary. Our experiments demonstrate that the proposed approaches yield substantial savings when compared to the brute-force one.\",\n \"Title: Fast inter mode decision based on textural segmentation and correlations for multiview video coding\\nYear: 2010\\n\\nAbstract: Multiview video coding (MVC) plays a critical role in reducing the ultra high data bandwidth of 3-D video. However, the heavy computational complexity of MVC slows down its applications. In this paper, a fast Inter mode decision based on textural segmentation and correlations is presented: Firstly, each frame is segmented into three textural regions based on the correlation between textural complexities and Intra mode Rate-Distortion (RD) costs, and the correlation of Intra mode RD costs between views. Then, by using textural region types and the correlation of Skip mode RD costs between views, an early decision of Skip mode is introduced. Thirdly, by utilizing Inter16×16 mode prediction results and textural region types, the disparity estimation of other Inter modes is selected. Finally, the estimation of Inter8×8 mode can be reduced according to textural region types and motion activity. As compared to the full mode decision in MVC reference software, experimental results show that the proposed algorithm can reduce 55~70% of the computational time, while maintaining high RD performance.\",\n \"Title: Factors Influencing Marketing Effectiveness on the Web\\nYear: 2001\\n\\nAbstract: Despite the current development of Internet marketing, understanding the effective use of the Internet still poses problems for academic researchers and marketers Kassaye, 1999. This research attempts to empirically explore some of the critical factors influencing commercial Internet and Web development. The key factors considered for company Internet and Web site development are aspects of technology capacity, the use of different Internet developers, the approaches used to evaluate on-line marketing effectiveness and the marketing executives' knowledge of Internet technology. As a result of a cross-sectional comparative study of 'effective' and 'ineffective' companies, the findings indicate that companies with higher on-line marketing effectiveness tend to possess higher levels of technological capabilities for Internet-based marketing. The results also show that their marketing executives have a better knowledge of technical aspects of Web site development. They tend to be early Internet adopters using a multiple approach to evaluate their on-line marketing efforts. These exploratory results indicate how on-line strategies could be made to be more effective.\",\n \"Title: On-Line Estimation And Correction Of Voltage Stability Index As Slack Nodes Failure\\nYear: 2013\\n\\nAbstract: Along with the widely application of the Wide-Area Measurement System in power system, voltage instability based on WAMS is becoming all increasingly important worldwide issue. By using the WAMS to collect the measured value of local voltage and current vector directly, we can realize the online estimate and instruction of the voltage stability degree of key node. Use this as a foundation, this paper analyses problems in the phase failure of slack node, puts forward that taking the voltage phase of the node, which has the nearest electrical distance from the slack node, as the reference phase; and according to the least square method based on historical data of WAMS two effective methods to correct and estimate the voltage andcurrent phasor of the key node, can also realize online correction and estimating of the voltage stability of the key node. The simulations show that this method is suitable for the surveillance of online static voltage stability of node and has certain feasibility.\",\n \"Title: Image Resizing Based on Geometry Preservation with Seam Carving\\nYear: 2012\\n\\nAbstract: When an image or a video is transformed to an aspect ratio deferent from its original size, information lost is inevitable no matter what method is used, thus, how to keep the most attractive contents and minimize the visual distortion during the resizing process is the key issue. To address this problem, this paper proposes an object geometry preservation method based on the seam carving method. We first define a framework that measures the importance of geometry feature in the source material, then a new energy function is presented with object geometry constraint, according to the new energy function, an optimized seam carving method is used to minimize distortion while resizing the source material. The experiment results show that our method is better to transform a variety of source images to a different display size than conventional resizing methods.\",\n \"Title: Lightweight content-adaptive coding in joint analyzing-encoding framework\\nYear: 2008\\n\\nAbstract: A novel joint analyzing-encoding framework is proposed in this paper. With this framework, the video analysis and the video coding can be integrated together, which can decrease the computational complexity of the video process system due to the obtained shared information. A lightweight content-adaptive video coding scheme can be achieved by using the presented framework for H.264 standard. The side encoding information, including motion vectors (MVs) and sum of absolute differences (SADs), can be used to reduce the computation cost of the moving region analysis. First, the rectangular shape and the displacement information of the moving region in the current encoded frame are obtained by employing a robust binary detection method, which is based on the adaptive threshold and the fast components labeling algorithm. Then, the rectangular shape information of the next frame is achieved by using a simple but effective prediction method, which considers the principle of the temporal motion constraint. Finally, a motion importance mask map (MIMP) is obtained according to the predicted rectangular shape information. Meanwhile, a category of frequency coefficient suppression(FCS) technique in the transform domain is presented to avoid the use of the complex MB-layer rate control method. With MIMP and FCS, a lightweight content-adaptive video coding scheme is realized based on a simple frame-layer rate control method. Experimental results show that the proposed scheme can detect and predict the moving regions fast and improve the objective/subjective visual quality significantly for the moving regions.\",\n \"Title: Tracking Coverage throughout Epochs with Bounded Uncertainty\\nYear: 2011\\n\\nAbstract: This work addresses the problem of managing the sensor-coverage and organizing the epochs in a manner that balances the trades-offs between the accuracy and energy consumptions during target tracking in Wireless Sensor Networks (WSN). While the typical target tracking approaches are based on movement prediction, we only assume a knowledge of some maximal speed of the target during certain time-intervals. This, in turn, restricts its whereabouts to a disk-bound area throughout such intervals. In such settings, we seek to determine a sensor cover, a subset of all the nodes that need to be awake, which ensures that the target can be detected during the given epoch. Towards this, we propose sensor-cover selection methodologies, Greedy Uncertain Moving Object coverage sensor set selection (GUMO) and PAttern Based coverage sensor set selection (PAB). GUMO is a heuristic maximizing the coverage gain at each step, while PAB is an approach based on optimal deployment pattern of sensor nodes achieving coverage of the disk area bounding the target's whereabouts. We conduct extensive simulations to evaluate the performance of the algorithms, and the results reveal that GUMO and PAB not only provide substantial energy saving due to reduction in the communications involved in selecting tracking participant-nodes and principal(s), while assuring a bounded error on the target's location.\",\n \"Title: Optimizing the live migration of virtual machine by CPU scheduling\\nYear: 2011\\n\\nAbstract: Live migration has been proposed to reduce the downtime for migrated VMs by pre-copying the generated run-time memory state files from the original host to the migration destination host. However, if the rate for such a dirty memory generation is high, it may take a long time to accomplish live migration because a large amount of data needs to be transferred. In extreme cases when dirty memory generation rate is faster than pre-copy speed, live migration will fail. In this work we address the problem by designing an optimization scheme for live migration, under which according to pre-copy speed, the VCPU working frequency may be reduced so that at a certain phase of the pre-copy the remaining dirty memory can reach a desired small amount. The VM downtime during the migration can be limited. The scheme works for the scenario where the migrated application has a high memory writing speed, or the pre-copy speed is slow, e.g., due to low network bandwidth between the migration parties. The method improves migration liveness at the cost of application performance, and works for those applications for which interruption causes much more serious problems than quality deterioration. Compared to the original live migration, our experiments show that the optimized scheme can reduce up to 88% of application downtime with an acceptable overhead.\",\n \"Title: Connectivity compression for stripified triangle meshes\\nYear: 2007\\n\\nAbstract: Modern graphics application systems have to render many 3D triangle mesh models, thereby facing problems of memory and bandwidth. A general significant solution is to compress the static 3D triangle mesh model at the preprocessing phase, especially the topological information. This paper presents a new triangle meshes compression algorithm, which encodes connectivity information between vertex chains in the meshes that are already stripified. The proposed algorithm provides a new representation that is guaranteed to encode any stripified meshes in less than 1.67 bits/T, and 1.05 bits/T on average. Furthermore, the proposed algorithm employs a short compression/decompression time. Hence it will satisfy real-time rendering constraints.\",\n \"Title: Bypassing Holes in Sensor Networks: Load-Balance vs. Latency.\\nYear: 2011\\n\\nAbstract: This work addresses the problem of geographic routing in the presence of holes or voids in wireless sensor networks. We postulate that, once the boundary of the hole has been established, relying on the existing algorithms for bypassing it may cause severe depletion of the energy reserves among the nodes at (or near) that boundary. This, in turn, may soon render some of those nodes useless for any routing (and/or sensing) purposes, thereby effectively enlarging the size of the pre-existing hole. To extend the lifetime of the nodes along the boundary of a given hole, we propose two heuristic approaches which aim at relieving some of the routing load of the boundary nodes. Towards that, our approaches propose that some of the routes that would otherwise need to bypass the hole along the boundary, should instead start to deviate from their original path further from the hole. Our experiments demonstrate that the proposed approaches not only increase the lifetime of the nodes along the boundary of a given hole, but also yield a more uniform depletion of the energy reserves in its vicinity.\",\n \"Title: Ontology Based Automatic Image Annotation Using Multi-class SVM\\nYear: 2013\\n\\nAbstract: Image annotation is usually formed as a multiclass classification problem. Traditional methods learn the co-occurrence of keywords and images while they ignore the correlation between keywords, which turned out to be one of the reasons causing poor experiment results. In this paper, we propose an automatic image annotation approach by using multiclass SVM with ontology to achieve a higher accuracy. In our paper, we choose semantic dictionary Word Net in which hierarchy defined words are derived from the text ontology to calculate the correlations between keywords. Specifically, we use Bags of Visual Words model to present the image visual feature and apply a mixed kernel in multiclass SVM. Finally, we combine the probability outputs to get the final results. Compared to other state-of-the-art multiclass classification methods, our approach tested in typical Corel dataset maintain a high level of accuracy in classification.\",\n \"Title: Analysis of Spectral Efficiency and Management of Cross-Tier Interference in Femtocell Network\\nYear: 2013\\n\\nAbstract: Femtocell is on the way of being extensively deployed in households to provide better indoor coverage and higher user capacity. However, as the coverage of femtocell is overlapped with that of conventional macrocell, the cross-tier interference may result in a considerable degradation of system performance in terms of spectral efficiency. This paper focuses on the improvement of cell spectral efficiency in two-tier network. We first derive the explicit expressions of cell spectral efficiency and average spectral efficiency of single user in each tier. Some remarks and observations are provided after analyzing numerical results of the expressions. Then based on the theoretical analysis, we propose a dynamic cross-tier interference coordination (D-CTIC) scheme. D-CTIC can provide high cell spectral efficiency by maximizing the number of coexistent femtocell base stations (FBSs) with macrocell base station (MBS) while still satisfying the QoS requirement of macrocell user (MUE) by restricting cross-tier interference under an acceptable level. Finally, simulation results verify the theoretical analysis and show that D-CTIC can enhance cell spectral efficiency significantly.\",\n \"Title: Research on supply chain versus supply chain competition with product quality and price dependent demand\\nYear: 2012\\n\\nAbstract: This paper firstly studies the quality and pricing competition between two supply chains providing two kinds of substitutable products with product quality and price dependent demand for an identical market, where each supply chain (Simply denoted as SC) consists of one manufacturer and one retailer. EPEC (Equilibrium Problems with Equilibrium Constrains) model, MPEC (Mathematical Programs with Equilibrium Constrains) model and Nash equilibrium model are set up by using game theory and equilibrium analysis method, which respectively characterize the competition equilibrium between two centralized SCs, two decentralized SCs, one centralized SC and one decentralized SC. Secondly, a profit-sharing contract is put forward to coordinate one decentralized SC to be centralized SC under SC vs. SC competition. Finally, numerical examples show the correctness of the models and the validity of the contract. It shows that coordination is a dominant strategy, and consumer are the beneficiaries who can obtain more consumer welfare since SC coordination leads lower retail prices and more supply quantities.\",\n \"Title: Trajectory Data Reduction In Wireless Sensor Networks\\nYear: 2010\\n\\nAbstract: This work addresses the problem of balancing the trade-off between the energy cost due to communication and the accuracy of the tracking-based trajectories' detection and representation in Wireless Sensor Networks (WSNs) settings. We consider some of the approaches used by the Moving Objects Databases (MOD) and Computational Geometry (CG) communities, and we demonstrate that with appropriate adaptation, they can yield significant benefits in terms of energy savings and, consequently, lifetime of a given WSN. Towards that, we developed distributed variations of three approaches for spatio-temporal data reduction - two heuristics (Dead-Reckoning and the Douglas-Peuker algorithm), and a variant of a CG-based optimal algorithm for polyline reduction. In addition, we examine different policies for managing the buffer used by the individual tracking nodes for storing the partial trajectory data. Lastly, we investigated the potential benefits of combining the different data-reduction approaches into \\\"hybrid\\\" ones during tracking of a particular object's trajectory. Our experiments demonstrate that the proposed methodologies can significantly reduce the network-wide energy expenses due to communication and increase the network lifetime.\",\n \"Title: Deflection-Aware Tracking-Principal Selection in Active Wireless Sensor Networks.\\nYear: 2012\\n\\nAbstract: This paper addresses the problem of energy efficiency balanced with tracking accuracy in wireless sensor networks (WSNs). Specifically, we focus on the issues related to selecting tracking principals, i.e., the nodes with two special tasks: 1) coordinating the activities among the sensors that are detecting the tracked object's locations in time and 2) selecting a node to which the tasks of coordination and data fusion will be handed off when the tracked object exits the sensing area of the current principal. Extending the existing results that based the respective principal selection algorithms on the assumption that the target's trajectory is approximated with straight line segments, we consider more general settings of (possibly) continuous changes of the direction of the moving target. We developed an approach based on particle filters to estimate the target's angular deflection at the time of a handoff, and we considered the tradeoffs between the expensive in-node computations incurred by the particle filters and the imprecision tolerance when selecting subsequent tracking principals. Our experiments demonstrate that the proposed approach yields significant savings in the number of handoffs and the number of unsuccessful transfers in comparison with previous approaches. © 1967-2012 IEEE.\",\n \"Title: Application of 4-point subdivision to generate in-between frames in skeletal animation\\nYear: 2006\\n\\nAbstract: Regarding the modeling aspects of computer animation, the skeletal animation is a newfangled modeling technology to assist in single-mesh model animation. There are two aspects of advancement proposed in this paper. First, we construct a novel vertical data structure (Modified Body-Tree) to describe the skeletal models in animation. Second, instead of normal methods such as linear interpolation and higher-order spline interpolation to generate in-between frame, we proposes an adaptive and high-performance algorithm based on 4-Point subdivision scheme to generate in-between frame in the skeletal animation. By this advanced algorithm, a smoother skeletal animation with blander vision effect is achieved.\",\n \"Title: Selecting tracking principals with epoch awareness\\nYear: 2010\\n\\nAbstract: This work addresses the problem of principal node selection during the tracking process in Wireless Sensor Networks (WSNs). In a typical tracking scenario, the location of a mobile unit is determined via collaborative trilateration by the nodes that have the tracked object within their sensing range. One of the participants in the trilateraion---the tracking principal---is in charge of transmitting the location and time information to a designated sink. However, as the moving object changes its location, a new principal needs to be determined and handed off the task of the subsequent sensing, trilateration and transmission to the sink. We observe that in many WSN applications in which sensing/sampling needs to be combined with multihop transmission and, possibly, in-network aggregation, the typical processing is organized in synchronized intervals, called epochs. We postulate that taking the semantics of the epoch into consideration is important when selecting tracking principals and we present efficient algorithmic solutions towards this goal. Our experiments demonstrate that the proposed approach can yield significant reduction in the number of hand-offs between consecutive tracking principals, when compared to previous works.\",\n \"Title: Predicting audience gender in online content-sharing social networks.\\nYear: 2013\\n\\nAbstract: Understanding the behavior and characteristics of web users is valuable when improving information dissemination, designing recommendation systems, and so on. In this work, we explore various methods of predicting the ratio of male viewers to female viewers onYouTube. First, we propose and examine two hypotheses relating to audience consistency and topic consistency. The former means that videos made by the same authors tend to have similar male-to-female audience ratios, whereas the latter means that videos with similar topics tend to have similar audience gender ratios. To predict the audience gender ratio before video publication, two features based on these two hypotheses and other features are used in multiple linear regression (MLR) and support vector regression (SVR). We find that these two features are the key indicators of audience gender, whereas other features, such as gender of the user and duration of the video, have limited relationships. Second, another method is explored to predict the audience gender ratio. Specifically, we use the early comments collected after video publication to predict the ratio via simple linear regression (SLR). The experiments indicate that this model can achieve better performance by using a few early comments. We also observe that the correlation between the number of early comments (cost) and the predictive accuracy (gain) follows the law of diminishing marginal utility. We build the functions of these elements via curve fitting to find the appropriate number of early comments (approximately 250) that can achieve maximum gain at minimum cost.\",\n \"Title: Method for fundamental matrix estimation combined with feature lines\\nYear: 2015\\n\\nAbstract: Fundamental matrix estimation has been studied extensively in the area of computer vision and previously proposed techniques include those that only use feature points. In this study, we propose a new technique for calculating the fundamental matrix combined with feature lines, which is based on the epipolar geometry of horizontal and vertical feature lines. First, a method for parameterizing the fundamental matrix is introduced, where the camera orientation elements and relative orientation elements are used as the parameters of the fundamental matrix, and the equivalent relationships are deduced based on the horizontal and vertical feature lines. Next, the feature lines are used as the interior points by the RANSAC algorithm to search for the optimal feature point subset, before determining the weight of each factor using the M-estimators algorithm and building a unified adjustment model to estimate the fundamental matrix. The experimental results obtained using simulated images and real images demonstrate that the proposed approach is feasible in practice and it can greatly reduce the dependency on feature points in the traditional method, while the introduction of feature lines can improve the accuracy and stability of the results to some extent.\",\n \"Title: An adaptive neural fuzzy network clothing comfort evaluation model and application in digital home\\nYear: 2014\\n\\nAbstract: With the development of digital TV, especially 3D technologies, some applications in the digital home industry have been reported to meet and even exceed customer expectation in the market place for enterprise. In order to evaluate the clothing comfort performance in the digital e-commerce service, the clothing comfort model is very important. Considered the physical, physiological and psychological factors, a theoretical clothing comfort evaluation model is presented based on the adaptive fuzzy neural network in this paper. According to the characters of clothing comfort, Fuzzy Neural Networks (FNN) can provide a very human machine knowledge representation scheme friendly for acquiring, representing and using the knowledge of the domain expert. This is a significant advantage for clothing comfort evaluation where the exact system transfer functions cannot be well modeled and adequate training data sets are not available. The experiment results shown that there has the same prediction trend about the experiment result and simulation result. This clothing comfort evaluation model is used as a component in the smart clothing function user experience system.\",\n \"Title: Dynamic cross-tier interference management in heterogeneous network\\nYear: 2013\\n\\nAbstract: As conventional single-layered network cannot satisfy the increasing demand in high-speed indoor data service, femtocell has been introduced to provide higher network capacity and better user experience. However, the downlink transmit signal from femtocell base station (FBS) may result in severe cross-tier interference to macrocell users (MUE). To address this problem, we propose a dynamic femtocell exclusion mechanism to alleviate the downlink cross-tier interference for MUE. The radius of the femtocell exclusion area, which is defined as reuse distance, is analyzed while taking account of the target outage probability and random position of the interfering FBSs. We derive the closed-form expression of the outage probability as a function of reuse distance. This expression provides a simple method to plan the exclusion area around the victim MUE. In addition, we introduce reuse table to avoid unpredictable interference caused by random appeared active FBS. Simulation results verify our theoretical analysis and show that the proposed mechanism can effectively alleviate the downlink cross-tier interference and improve the user capacity of the network.\",\n \"Title: Spatio-temporal correlation-based fast coding unit depth decision for high efficiency video coding\\nYear: 2013\\n\\nAbstract: The exhaustive block partition search process in high efficiency video coding (HEVC) imposes a very high computational complexity on test module of HEVC encoder (HM). A fast coding unit (CU) depth algorithm using the spatio-temporal correlation of the depth information to fasten the search process is proposed. The depth of the coding tree unit (CTU) is predicted first by using the depth information of the spatio-temporal neighbor CTUs. Then, the depth information of the adjacent CU is incorporated to skip some specific depths when encoding the sub-CTU. As compared with the original HM encoder, experimental results show that the proposed algorithm can save more than 20% encoding time on average for intra-only, low-delay, low-delay P slices, and random access cases with almost the same rate-distortion performance. (C) 2013 SPIE and IS&T\",\n \"Title: A nonlinear smoother for target tracking in asynchronous wireless sensor networks\\nYear: 2015\\n\\nAbstract: Generally, multiple sensors are deployed to track a target synchronously in wireless sensor networks. However, asynchronous measurements exist intrinsically in multi-rate multi-sensor systems. Asynchronous measurements may also emerge in acoustic sensor networks, owing to the low propagation speed of acoustic signals. In order to handle the target tracking problem with asynchronous measurements, a nonlinear smoothing algorithm based on the fixed-point smoother and the square-root cubature Kalman filter is derived and applied in asynchronous wireless sensor networks for the first time. The estimation precision of the states increases along with the smoothing process, and a sensor can always obtain the optimal estimate of a state before its own next measurement by using the proposed algorithm. The numerical simulations demonstrate that, thanks to the smoothing effect of the fixed-point smoother, the proposed algorithm can obtain not only the remarkable position estimation results of the target, but also even better velocity estimation results. In addition, the proposed algorithm can obtain much more states' estimates than benchmark synchronous target-tracking algorithms, under the same condition of measurement count and communication cost.\",\n \"Title: Retiling scheme: a novel approach of direct anisotropic quad-dominant remeshing.\\nYear: 2016\\n\\nAbstract: Remeshing has been an active research topic in Digital Geometry Processing. In this paper, a novel approach of direct anisotropic quad-dominant remeshing is proposed. We apply the retiling method to the particular problem of quad-dominant remeshing. Compared with other methods, this method can simply partition the surface of an original triangular mesh into connected quads with the mesh edges aligning to the principal directions. The first step in this method is to estimate and smooth the curvature tensor field of the surface at the vertices, and then the quad-dominant mesh is obtained by retiling the quad surface so that quadrilateral edges are parallel to the local principal curvature directions. In addition, to preserve the sharp feature information during remeshing processes, the feature lines can be extracted using mesh segmentation method, and the intersections between the feature lines and the orthogonal planes can be found during the process of retiling. A feature fusion process is presented to join the feature edges and feature points into the quad-dominant mesh. The experiment results show that this new remeshing method is simple and easy to implement. The resolution of the quadrilateral mesh can be controlled during the remeshing. It is applicable to arbitrary genus meshes and can generate high-quality quad-dominant mesh.\",\n \"Title: Learning-Based and Data-Driven TCP Design for Memory-Constrained IoT\\nYear: 2016\\n\\nAbstract: Advances in wireless technology have resulted in pervasive deployment of devices of a high variability in form factors, memory and computational ability. The need for maintaining continuous connections that deliver data with high reliability necessitate re-thinking of conventional design of the transport layer protocol. This paper investigates the use of Q-learning in TCP cwnd adaptation during the congestion avoidance state, wherein the classical alternation of the window is replaced, thereby allowing the protocol to immediately respond to previously seen network conditions. Furthermore, it demonstrates how memory plays a critical role in building the exploration space, and proposes ways to reduce this overhead through function approximation. The superior performance of the learning-based approach over TCP New Reno is demonstrated through a comprehensive simulation study, revealing 33.8% and 12.1% improvement in throughput and delay, respectively, for the evaluated topologies. We also show how function approximation can be used to dramatically reduce the memory requirements of a learning-based protocol while maintaining the same throughput and delay.\",\n \"Title: Efficient multi-account detection on UGC sites\\nYear: 2016\\n\\nAbstract: This work presents a novel writing style-based approach to detect multi-account users on User-Generated Content (UGC) sites. Unlike existing works which emphasize feasibility and privacy leakage, we focus on precise writing style-based multi-account detection. Specifically, we leverage a one-class classification-based approach to detect multi-account behaviors, in which a mutual similarity measurement is defined to increase detection precision. In addition to traditional features used in writing style detection, we also extract bigrams, trigrams, part-of-speech, and grammatical relations. We evaluate our methodology based on datasets crawled from 3 popular OSNs (i.e., Twitter, Facebook, and Google+). Experimental results demonstrate that compared with the most recent achievements, our method not only improves the average detection precision to almost 90%, but also increases both recall and F-measure to 90% and even better.\",\n \"Title: Genome-wide association analysis of secondary imaging phenotypes from the Alzheimer's disease neuroimaging initiative study.\\nYear: 2017\\n\\nAbstract: The aim of this paper is to systematically evaluate a biased sampling issue associated with genome-wide association analysis (GWAS) of imaging phenotypes for most imaging genetic studies, including the Alzheimer's Disease Neuroimaging Initiative (ADNI). Specifically, the original sampling scheme of these imaging genetic studies is primarily the retrospective case-control design, whereas most existing statistical analyses of these studies ignore such sampling scheme by directly correlating imaging phenotypes (called the secondary traits) with genotype. Although it has been well documented in genetic epidemiology that ignoring the case-control sampling scheme can produce highly biased estimates, and subsequently lead to misleading results and suspicious associations, such findings are not well documented in imaging genetics. We use extensive simulations and a large-scale imaging genetic data analysis of the Alzheimer's Disease Neuroimaging Initiative (ADNI) data to evaluate the effects of the case-control sampling scheme on GWAS results based on some standard statistical methods, such as linear regression methods, while comparing it with several advanced statistical methods that appropriately adjust for the case-control sampling scheme.\",\n \"Title: ActiveRec: A Novel Context-Sensitive Ranking Method for Active Movie Recommendation\\nYear: 2016\\n\\nAbstract: This paper presents a novel context-sensitive ranking algorithm, called ActiveRec, for providing flexible movie recommendations. Typically, ActiveRec can recommend movies to a user according to a specific movie type, or to a group of users satisfying their common interests. Firstly, ActiveRec constructs a multipartite graph where the nodes represent users, movies, and joint information, respectively. And then, a biased random-walk is performed to obtain the similarity between the request vector and every node on the graph. Based on the similarities, ActiveRec sorts out all movies that meet the user requirements and notify the user of a Top-N list. Additionally, a time-decay model following the Ebbinghaus forgetting curve is introduced to imitate the decay process of the importance of users' feedbacks when computing the edges' weights in the graph. Extensive experiments are performed on a real dataset to evaluate the performance. The results demonstrate that ActiveRec not only satisfies the requirements of flexible recommendations, but also achieves higher performance compared to the existing works.\",\n \"Title: Shaping LDLC Lattices Using Convolutional Code Lattices\\nYear: 2017\\n\\nAbstract: In this letter, we show how to construct low-density lattice code (LDLC) lattices shaped using convolutional code lattices. First, we give an explicit method to find the generator matrices of convolutional code lattices. The shaping gain of convolutional code lattices based on rate 1/2 convolutional codes for short block length is found by evaluating the normalized second moment; a shaping gain as high as 1.24 dB for dimension $n=200$ was found. Then, nested LDLC lattices are constructed. We design LDLC lattices that satisfy conditions necessary for forming nested lattice codes, and give a specific example. For an $n=36$ dimensional lattice, a lattice code based on LDLC lattices, shaped using convolutional code lattices, has a shaping gain of 0.87 dB, over hypercube shaping.\",\n \"Title: Efficient detection of motion-trend predicates in wireless sensor networks.\\nYear: 2017\\n\\nAbstract: This work addresses the problem of efficient distributed detection of predicates capturing the motion trends of mobile objects evaluated with respect to a (boundary of a) polygonal region, in the settings in which the (location, time) data is obtained via tracking in Wireless Sensor Networks (WSN). Specifically, we discuss in-network distributed algorithms for detecting two motion-trend predicates: Continuously Moving Towards and Persistently Moving Towards: first for a single object, and then the corresponding variants for multiple objects. We also present methodologies which consider the energy vs. latency trade-offs when multiple tracked objects are being considered for validating the monitored predicates. Our experiments demonstrate that our proposed technique yield substantial energy savings when compared to the nave centralized and cluster-based approaches in which the raw (location, time) data is transmitted to a dedicated sink where the predicates are being evaluated.\",\n \"Title: Bypassing holes in sensor networks: Load-balance vs. latency.\\nYear: 2017\\n\\nAbstract: This work addresses problems that arise when geographic routing is used in the presence of holes in wireless sensor networks. We postulate that relying on the existing algorithms for bypassing a coverage hole may cause more severe depletion of the energy reserves among the nodes at (or near) that hole’s boundary. This, in turn, will render some of those nodes useless for any routing (and/or sensing) purposes, thereby effectively enlarging the size of existing hole and inducing longer communication delays for certain (source, sink) pairs. We propose heuristics that address these complementary problems: (1) relieving some of the routing-load for the nodes around the boundary of a given hole, for the purpose of extending their lifetime; and (2) reducing the latency of the packets-delivery by using routes that are within certain bounds from the route based on the shortest-path. Our approaches are based on the idea that some of the packets that would (otherwise) need to be routed along the boundary of a given hole, should instead start to deviate from their original path further away from that hole. To investigate the potential benefits, we introduce approximations of the hole’s boundary with a rectangle, a circle and an ellipse, respectively. We derive the bounds on reducing the routing latency for these three approximations. Our experiments demonstrate that the proposed approaches not only increase the lifetime of the nodes along the boundary of a given hole and yield a more uniform depletion of the energy reserves in its vicinity, but also reduce the communication latency, compared to the traditional face routing.\",\n \"Title: Dynamic Generalization Kanerva Coding in Reinforcement Learning for TCP Congestion Control Design.\\nYear: 2017\\n\\nAbstract: Traditional reinforcement learning (RL) techniques often encounter limitations when solving large or continuous state-action spaces. Training times needed to explore the very large space are impractically long, and it can be difficult to generalize learned knowledge. A compact representation of the state space is usually generated to solve both problems. However, simple state abstraction often cannot achieve the desired learning quality, while expert state representations usually involve costly hand-crafted strategies. We propose a new technique, generalization-based Kanerva coding, that automatically generates and optimizes state abstractions for learning. When applied to adapting the congestion window of the highly complex TCP congestion control protocol, a standard Internet protocol, this technique outperforms the current standard-TCP New Reno by 59.5% in throughput and 6.5% in delay. Our technique also achieves a 35.2% improvement in throughput over the best previously proposed Kanerva coding technique when applied in the same context.\",\n \"Title: Illumination insensitive efficient second-order minimization for planar object tracking.\\nYear: 2017\\n\\nAbstract: Tracking for planar objects is an important issue to vision-based robotic applications. In direct visual tracking (DVT) methods, the similarity between two images is often measured through the sum of squared differences (SSD) especially with the efficient second-order minimization (ESM) due to its simplicity and efficiency. However, SSD-based ESM is not robust to illumination changes since it is usually built upon the brightness constancy assumption. Contrast to image brightness, gradient orientations (GO) are invariant to both linear and non-linear illumination changes as verified in practice. Based on GO, we propose an illumination insensitive ESM method for planar object tracking in this paper. In order to introduce GO into the ESM, we generalized the original ESM formulas for multi-dimensional features. In addition, a denoising method based on the Perona-Malik function and a mask image were suggested to improve GOu0027s robustness against image noise and low texture. Our experimental results on dataset for planar objects with illumination changes and a benchmark dataset confirm the proposed method is robust to illumination variations and capable to deal with the general tracking challenges.\",\n \"Title: The $\\\\ell_\\\\infty$ Perturbation of HOSVD and Low Rank Tensor Denoising.\\nYear: 2017\\n\\nAbstract: The higher order singular value decomposition (HOSVD) of tensors is a generalization of matrix SVD. The perturbation analysis of HOSVD under random noise is more delicate than its matrix counterpart. Recent progress has been made in Richard and Montanari (2014), Zhang and Xia (2017) and Liu et al. (2017) demonstrating that minimax optimal singular spaces estimation and low rank tensor recovery in $ell_2$-norm can be obtained through polynomial time algorithms. In this paper, we analyze the HOSVD perturbation under Gaussian noise based on a second order method, which leads to an estimator of singular vectors with sharp bound in $ell_infty$-norm. A low rank tensor denoising estimator is then proposed which achieves a fast convergence rate characterizing the entry-wise deviations. The advantages of these $ell_infty$-norm bounds are displayed in applications including high dimensional clustering and sub-tensor localizations.\",\n \"Title: Identifying Human Mobility via Trajectory Embeddings.\\nYear: 2017\\n\\nAbstract: Understanding human trajectory patterns is an important task in many location based social networks (LBSNs) applications, such as personalized recommendation and preference-based route planning. Most of the existing methods classify a trajectory (or its segments) based on spatio-temporal values and activities, into some predefined categories, e.g., walking or jogging. We tackle a novel trajectory classification problem: we identify and link trajectories to users who generate them in the LBSNs, a problem called Trajectory-User Linking (TUL). Solving the TUL problem is not a trivial task because: (1) the number of the classes (i.e., users) is much larger than the number of motion patterns in the common trajectory classification problems; and (2) the location based trajectory data, especially the check-ins, are often extremely sparse. To address these challenges, a Recurrent Neural Networks (RNN) based semi-supervised learning model, called TULER (TUL via Embedding and RNN) is proposed, which exploits the spatio-temporal data to capture the underlying semantics of user mobility patterns. Experiments conducted on real-world datasets demonstrate that TULER achieves better accuracy than the existing methods.\",\n \"Title: Association Rules Mining with Quantum Computing and Quantum Storage\\nYear: 2017\\n\\nAbstract: The rapid development of big data puts forward higher requirements on computational efficiency and storage capacity. But the traditional mining algorithms based on classical computing were unable to satisfy the demand of data analysis and computing. Because of quantum systems unique ability of hyper parallel computation and hyper acceleration, the large-scale computing and data storage can be solve well. Although the development of quantum computer has not yet achieved a qualitative leap, quantum computing in big data application has achieved lots of theoretical achievements. In this paper, we make quantum data mining as a starting point. Since we have no sufficient space to store candidate sets of association rules and have low computation ability in the processing of association rules, we propose a novel quantum method of data storage and retrieval for association rules mining based on Boolean matrix, we propose the algorithm called Q-Eclat can accelerate the computation of candidate sets support. According to our analysis based on open data source, the proposed method outperforms the classical Eclat algorithm in terms of storage capacity and computing ability.\",\n \"Title: A Data-Driven Approach for Sketch-Based 3D Shape Retrieval via Similar Drawing-Style Recommendation.\\nYear: 2017\\n\\nAbstract: Sketching is a simple and natural way of expression and communication for humans. For this reason, it gains increasing popularity in human computer interaction, with the emergence of multitouch tablets and styluses. In recent years, sketch-based interactive methods are widely used in many retrieval systems. In particular, a variety of sketch-based 3D model retrieval works have been presented. However, almost all of these works focus on directly matching sketches with the projection views of 3D models, and they suffer from the large differences between the sketch drawing and the views of 3D models, leading to unsatisfying retrieval results. Therefore, in this paper, during the matching procedure in the retrieval, we propose to match the sketch with each 3D model from historical users instead of projection views. Yet since the sketches between the current user and the historical users can have big difference, we also aim to handle users' personalized deviations and differences. To this end, we leverage recommendation algorithms to estimate the drawing style characteristic similarity between the current user and historical users. Experimental results on the Large Scale Sketch Track Benchmark(SHREC14LSSTB) demonstrate that our method outperforms several state-of-the-art methods.\",\n \"Title: Towards Fast Flow Convergence in Cognitive Radio Cellular Networks.\\nYear: 2017\\n\\nAbstract: Cognitive radio (CR) is an enabling technology that allows opportunistic use of under-utilized licensed spectrum allocated to primary users (PUs). However, the frequent channel sensing and switching interferes with the transport layer functions, leading to slow flow convergence during active transmissions by the CR. In this paper, we propose TCP C-2, a method that greatly improves the flow responsiveness to abrupt variation of underlying layer spectrum availability in cellular CR architectures. The key idea of C-2 is to allow the sender to estimate the current bottleneck link bandwidth and network load by observing variance in the throughput and round trip time. Following this, fast congestion window scaling allows the flow to converge quickly to the optimal sending rate. Analytic derivations and packet-based simulation results show the increased resiliency of our approach over classical end-to-end TCP protocols in the presence of intermittent spectrum sensing and disruptions caused by PU arrival. Additionally, we show that C-2 enforces fairness among flows, and also coexists well with classical TCP flavors.\",\n \"Title: TPCNN: Two-Phase Patch-Based Convolutional Neural Network for Automatic Brain Tumor Segmentation and Survival Prediction.\\nYear: 2017\\n\\nAbstract: The aim of this paper is to integrate some advanced statistical methods with modern deep learning methods for tumor segmentation and survival time prediction in the BraTS 2017 challenge. The goals of the BraTS 2017 challenge are to utilize multi-institutional pre-operative MRI scans to segment out different tumor subregions and then to use tumor information to predict patient's overall survival. We build a twophase patch-based convolutional neural network (TPCNN) model to classify all the pixels in the brain and further refine the segmentation results by using XGBoost and a post-processing procedure. The segmentation results are then used to extract various informative radiomic features for prediction of the survival time by using the XGBoost method.\",\n \"Title: Torque sensorless decentralized neuro-optimal control for modular and reconfigurable robots with uncertain environments.\\nYear: 2018\\n\\nAbstract: A technical challenge of addressing the decentralized optimal control problem for modular and reconfigurable robots (MRRs) during environmental contacts is associated with optimal compensation of the uncertain contact force without using force/torque sensors. In this paper, a decentralized control approach is presented for torque sensorless MRRs in contact with uncertain environment via an adaptive dynamic programming (ADP)-based neuro-optimal compensation strategy. The dynamic model of the MRRs is formulated based on a novel joint torque estimation method, which is deployed for each joint model, and the joint dynamic information is utilized effectively to design the feedback controllers, thus making the decentralized optimal control problem of the environmental contacted MRR systems be formulated as an optimal compensation issue of model uncertainty. By using the ADP method, a local online policy iteration algorithm is employed to solve the Hamilton–Jacobi–Bellman (HJB) equation with a modified cost function, which is approximated by constructing a critic neural network, and then the approximate optimal control policy can be derived. The asymptotic stability of the closed-loop MRR system is proved by using the Lyapunov theory. At last, simulations and experiments are performed to verify the effectiveness of the proposed method.\",\n \"Title: Automatic Registration of Images With Inconsistent Content Through Line-Support Region Segmentation and Geometrical Outlier Removal.\\nYear: 2018\\n\\nAbstract: The implementation of automatic image registration is still difficult in various applications. In this paper, an automatic image registration approach through line-support region segmentation and geometrical outlier removal is proposed. This new approach is designed to address the problems associated with the registration of images with affine deformations and inconsistent content, such as remote ...\",\n \"Title: A Label-Fusion-Aided Convolutional Neural Network For Isointense Infant Brain Tissue Segmentation\\nYear: 2018\\n\\nAbstract: The extremely low tissue contrast in white matter during an infant's isointense stage (6-8 months) of brain development presents major difficulty when segmenting brain image regions for analysis. We sought to develop a label-fusion-aided deep-learning approach for automatically segmenting isointense infant brain images into white matter, gray matter and cerebrospinal fluid using T-1- and T-2-weighted magnetic resonance images. A key idea of our approach is to apply the fully convolutional neural network (FCNN) to individual brain regions determined by a traditional registration-based segmentation method instead of training a single model for the whole brain. This provides more refined segmentation results by capturing more region-specific features. We show that this method outperforms traditional joint label fusion and FCNN-only methods in terms of Dice coefficients using the dataset from iSEG MICCAI Grand Challenge 2017.\",\n \"Title: Trajectory-User Linking via Variational AutoEncoder.\\nYear: 2018\\n\\nAbstract: Trajectory-User Linking (TUL) is an essential task in Geo-tagged social media (GTSM) applications, enabling personalized Point of Interest (POI) recommendation and activity identification. Existing works on mining mobility patterns often model trajectories using Markov Chains (MC) or recurrent neural networks (RNN) - either assuming independence between non-adjacent locations or following a shallow generation process. However, most of them ignore the fact that human trajectories are often sparse, high-dimensional and may contain embedded hierarchical structures. We tackle the TUL problem with a semi-supervised learning framework, called TULVAE (TUL via Variational AutoEncoder), which learns the human mobility in a neural generative architecture with stochastic latent variables that span hidden states in RNN. TULVAE alleviates the data sparsity problem by leveraging large-scale unlabeled data and represents the hierarchical and structural semantics of trajectories with high-dimensional latent variables. Our experiments demonstrate that TULVAE improves efficiency and linking performance in real GTSM datasets, in comparison to existing methods.\",\n \"Title: Automatically Detecting the Scopes of Source Code Comments.\\nYear: 2018\\n\\nAbstract: •This work proposes the first method to detect the scopes of block/line comments•The detection of comment scopes can be modeled as a binary classification problem•We propose discriminative features in code and comments to characterize the scopes of comments.•We apply our method to two existing approaches in software engineering tasks and improve their performance.\",\n \"Title: Automatic Detection of Outdated Comments During Code Changes\\nYear: 2018\\n\\nAbstract: Comments are used as standard practice in software development to increase the readability of code and to express programmers' intentions in a more explicit manner. Nevertheless, keeping comments up-to-date is often neglected for programmers. In this paper, we proposed a machine learning based method for detecting the comments that should be changed during code changes. We utilized 64 features, taking the code before and after changes, comments and the relationship between the code and comments into account. Experimental results show that 74.6% of outdated comments can be detected using our method, and 77.2% of our detected outdated comments are real comments which require to be updated. In addition, the experimental results indicate that our model can help developers to discover outdated comments in historical versions of existing projects.\",\n \"Title: Identifying Brain Networks of Multiple Time Scales via Deep Recurrent Neural Network.\\nYear: 2018\\n\\nAbstract: For decades, task-based functional magnetic resonance imaging (tfMRI) has been a powerful noninvasive tool to explore the organizational architecture of human brain function. Researchers have developed a variety of brain network analysis methods for tfMRI data, including the general linear model (GLM), independent component analysis (ICA) and sparse representation methods. However, these shallow models are limited in faithful reconstruction and modeling of the hierarchical and temporal structures of brain networks, as demonstrated in more and more studies. Recently, recurrent neural networks (RNNs) exhibit great ability of modeling hierarchical and temporal dependency features in the machine learning field, which might be suitable for tfMRI data modeling. To explore such possible advantages of RNNs for tfMRI data, we propose a novel framework of deep recurrent neural network (DRNN) to model the functional brain networks for tfMRI data. Experimental results on the motor task tfMRI data of Human Connectome Project 900 subjects data release demonstrated that the proposed DRNN can not only faithfully reconstruct functional brain networks, but also identify more meaningful brain networks with multiple time scales which are overlooked by traditional shallow models. In general, this work provides an effective and powerful approach to identifying functional brain networks of multiple time scales from tfMRI data.\",\n \"Title: vec2Link: Unifying Heterogeneous Data for Social Link Prediction.\\nYear: 2018\\n\\nAbstract: Recent advances in network representation learning have enabled significant improvements in the link prediction task, which is at the core of many downstream applications. As an increasing amount of mobility data becoming available due to the development of location technologies, we argue that this resourceful user mobility data can be used to improve link prediction performance. In this paper, we propose a novel link prediction framework that utilizes user offline check-in behavior combined with user online social relations. We model user offline location preference via probabilistic factor model and represent user social relations using neural network embedding. Furthermore, we employ locality-sensitive hashing to project the aggregated user representation into a binary matrix, which not only preserves the data structure but also speeds up the followed convolutional network learning. By comparing with several baseline methods that solely rely on social network or mobility data, we show that our unified approach significantly improves the performance.\",\n \"Title: DeepLink: A Deep Learning Approach for User Identity Linkage.\\nYear: 2018\\n\\nAbstract: The typical aim of User Identity Linkage (UIL) is to detect when users from across different social platforms are actually one and the same individual. Existing efforts to address this problem of practical relevance span from user-profile-based, through user-generated-content-based, user-behavior-based approaches to supervised or unsupervised learning frameworks, to subspace learning-based models. Most of them often require extraction of relevant features (e.g., profile, location, biography, networks, behavior, etc.) to model the user consistently across different social networks. However, these features are mainly derived based on prior knowledge and may vary for different platforms and applications. Inspired by the recent successes of deep learning in different tasks, especially in automatic feature extraction and representation, we propose a deep neural network based algorithm for UIL, called DeepLink. It is a novel end-to-end approach in a semi-supervised learning manner, without involving any hand-crafting features. Specifically, DeepLink samples the networks and learns to encode network nodes into vector representation to capture local and global network structures which, in turn, can be used to align anchor nodes through deep neural networks. A dual learning based paradigm is exploited to learn how to transfer knowledge and update the linkage using the policy gradient method. Experiments conducted on several public datasets show that DeepLink outperforms the state-of-the-art methods in terms of both linking precision and identity-match ranking.\",\n \"Title: Making the Right Connections: Multi-AP Association and Flow Control in 60GHz Band.\\nYear: 2018\\n\\nAbstract: Emerging network architectures in 60GHz millimeter wave bands will likely use dense deployment of access points (APs) given the high attenuation and frequent line-of-sight related outages. We show in this paper that naively connecting to any available AP, or even multiple APs, may not fully realize the promise of efficiently utilizing the extremely large bandwidths available in this band. This paper holistically addresses these problems through the Multi-AP Association Protocol (MAP) that: (i) indicates ideal durations for beam-searching at the physical/link layers of the protocol stack that will result in minimal interruptions to user-traffic, (ii) devises a Multi-AP association framework based on multipath TCP, which increases the network robustness by allowing immediate redirection of traffic to alternative APs whenever an existing connection is interrupted, and (iii) designs an exploration-exploitation aware flow scheduling algorithm that dynamically activates the sub flows to optimize transport layer performance. MAP is a lightweight, client side system that needs zero modifications to existing protocol stack, though it interacts with the latter to opportunistically trigger standards-defined functions. The paper also presents convergence analysis of throughput, experimental validation on a 60GHz network testbed, and trace-driven simulation studies that shows MAP achieving 5-7x reduction in re-buffering rate in HI) video streaming, rapid convergence to the best possible AP, and fair allocation of resources among clients.\",\n \"Title: Implicit Dual-domain Convolutional Network for Robust Color Image Compression Artifact Reduction.\\nYear: 2018\\n\\nAbstract: Several dual-domain convolutional neural network-based methods show outstanding performance in reducing image compression artifacts. However, they suffer from handling color images because the compression processes for gray-scale and color images are completely different. Moreover, these methods train a specific model for each compression quality and require multiple models to achieve different compression qualities. To address these problems, we proposed an implicit dual-domain convolutional network (IDCN) with the pixel position labeling map and the quantization tables as inputs. Specifically, we proposed an extractor-corrector framework-based dual-domain correction unit (DRU) as the basic component to formulate the IDCN. A dense block was introduced to improve the performance of extractor in DRU. The implicit dual-domain translation allows the IDCN to handle color images with the discrete cosine transform (DCT)-domain priors. A flexible version of IDCN (IDCN-f) was developed to handle a wide range of compression qualities. Experiments for both objective and subjective evaluations on benchmark datasets show that IDCN is superior to the state-of-the-art methods and IDCN-f exhibits excellent abilities to handle a wide range of compression qualities with little performance sacrifice and demonstrates great potential for practical applications.\",\n \"Title: Trajectory-based social circle inference.\\nYear: 2018\\n\\nAbstract: Learning explicit and implicit patterns in human trajectories plays an important role in many Location-Based Social Networks (LBSNs) applications, such as trajectory classification (e.g., walking, driving, etc.), trajectory-user linking, friend recommendation, etc. A particular problem that has attracted much attention recently - and is the focus of our work - is the Trajectory-based Social Circle Inference (TSCI), aiming at inferring user social circles (mainly social friendship) based on motion trajectories and without any explicit social networked information. Existing approaches addressing TSCI lack satisfactory results due to the challenges related to data sparsity, accessibility and model efficiency. Motivated by the recent success of machine learning in trajectory mining, in this paper we formulate TSCI as a novel multi-label classification problem and develop a Recurrent Neural Network (RNN)-based framework called DeepTSCI to use human mobility patterns for inferring corresponding social circles. We propose three methods to learn the latent representations of trajectories, based on: (1) bidirectional Long Short-Term Memory (LSTM); (2) Autoencoder; and (3) Variational autoencoder. Experiments conducted on real-world datasets demonstrate that our proposed methods perform well and achieve significant improvement in terms of macro-R, macro-F1 and accuracy when compared to baselines.\",\n \"Title: Identifying Brain Networks at Multiple Time Scales via Deep Recurrent Neural Network.\\nYear: 2019\\n\\nAbstract: For decades, task-based functional magnetic resonance imaging (tfMRI) has been a powerful noninvasive tool to explore the organizational architecture of human brain function. Researchers have developed a variety of brain network analysis methods for tfMRI data, including the general linear model (GLM), independent component analysis (ICA) and sparse representation methods. However, these shallow models are limited in faithful reconstruction and modeling of the hierarchical and temporal structures of brain networks, as demonstrated in more and more studies. Recently, recurrent neural networks (RNNs) exhibit great ability of modeling hierarchical and temporal dependency features in the machine learning field, which might be suitable for tfMRI data modeling. To explore such possible advantages of RNNs for tfMRI data, we propose a novel framework of deep recurrent neural network (DRNN) to model the functional brain networks from tfMRI data. Experimental results on the motor task tfMRI data of Human Connectome Project 900 subjects release demonstrated that the proposed DRNN can not only faithfully reconstruct functional brain networks, but also identify more meaningful brain networks with multiple time scales which are overlooked by traditional shallow models. In general, this work provides an effective and powerful approach to identifying functional brain networks of multiple time scales from fMRI data.\",\n \"Title: An Efficient and Secure Two-Factor Password Authentication Scheme With Card Reader(Terminal) Verification.\\nYear: 2018\\n\\nAbstract: With regard to the privacy of client-server communication systems, most research works have concentrated on authentication to guarantee security. Among the investigated schemes, two-factor password authentication has been a major focus and has undergone considerable development. Two-factor password authentication is a process in which both a password and a physical object are used for authentication to achieve a higher level of security. However, these methods are still subject to some security vulnerabilities, such as malicious card reader attacks, man-in-the-middle attacks, and a lack of perfect forward secrecy. Moreover, although there are many evaluation criteria, there still lacks a set of universal criteria. To address these issues, a two-factor password authentication scheme is proposed in the context of practical application environment in this paper, such as side-channel attacks. Moreover, a card reader verification step is added to the authentication scheme to counteract malicious card reader attacks. In addition, the proposed scheme can resist various known attacks, including replay attacks, lost or stolen smart card attacks, and man-in-the-middle attacks. We present a detailed security analysis and comparative evaluation, and we prove the security of our scheme with Burrows-Abadi-Needham (BAN) logic. Compared with previous schemes, the main advantages of the proposed scheme are its low computational cost, guaranteed security, and better adaptability to actual client-server communication environments.\",\n \"Title: Dilated residual encode-decode networks for image denoising.\\nYear: 2018\\n\\nAbstract: Owing to recent advancements, very deep convolutional neural networks (CNNs) have found application in image denoising. However, while deeper models lead to better restoration performance, they are marred by a high number of parameters and increased training difficulty. To address these issues, we propose a CNN-based framework, named dilated residual encode-decode networks (DRED-Net), for image denoising, which learns direct end-to-end mappings from corrupted images to obtain clean images using few parameters. Our proposed network consists of multiple layers of convolution and deconvolution operators; in addition, we use dilated convolutions to boost the performance of our network without increasing the depth of the model or its complexity. Extensive experiments on synthetic noisy images are conducted to evaluate DRED-Net, and the results are compared with those obtained using state-of-the-art denoising methods. Our experimental results show that DRED-Net leads to results comparable with those obtained using other state-of-the-art methods for image denoising tasks. (C) 2018 SPIE and IS&T\",\n \"Title: A New Entropy-Based Atrial Fibrillation Detection Method for Scanning Wearable ECG Recordings.\\nYear: 2018\\n\\nAbstract: Entropy-based atrial fibrillation (AF) detectors have been applied for short-term electrocardiogram (ECG) analysis. However, existing methods suffer from several limitations. To enhance the performance of entropy-based AF detectors, we have developed a new entropy measure, named Entropy(AF), which includes the following improvements: (1) use of a ranged function rather than the Chebyshev function to define vector distance, (2) use of a fuzzy function to determine vector similarity, (3) replacement of the probability estimation with density estimation for entropy calculation, (4) use of a flexible distance threshold parameter, and (5) use of adjusted entropy results for the heart rate effect. Entropy(AF) was trained using the MIT-BIH Atrial Fibrillation (AF) database, and tested on the clinical wearable long-term AF recordings. Three previous entropy-based AF detectors were used for comparison: sample entropy (SampEn), fuzzy measure entropy (FuzzyMEn) and coefficient of sample entropy (COSEn). For classifying AF and non-AF rhythms in the MIT-BIH AF database, Entropy(AF) achieved the highest area under receiver operating characteristic curve (AUC) values of 98.15% when using a 30-beat time window, which was higher than COSEn with AUC of 91.86%. SampEn and FuzzyMEn resulted in much lower AUCs of 74.68% and 79.24% respectively. For classifying AF and non-AF rhythms in the clinical wearable AF database, Entropy(AF) also generated the largest values of Youden index (77.94%), sensitivity (92.77%), specificity (85.17%), accuracy (87.10%), positive predictivity (68.09%) and negative predictivity (97.18%). COSEn had the second-best accuracy of 78.63%, followed by an accuracy of 65.08% in FuzzyMEn and an accuracy of 59.91% in SampEn. The new proposed Entropy(AF) also generated highest classification accuracy when using a 12-beat time window. In addition, the results from time cost analysis verified the efficiency of the new Entropy(AF). This study showed the better discrimination ability for identifying AF when using Entropy(AF) method, indicating that it would be useful for the practical clinical wearable AF scanning.\",\n \"Title: Predicting Topic Participation By Jointly Learning User Intrinsic And Extrinsic Preference\\nYear: 2019\\n\\nAbstract: Understanding the preferences of social media participants plays a crucial role in many business applications. A specific aspect of interest is to predict which topics a particular user is more likely to be involved in. Existing efforts on such topic participation forecasting mainly focus on learning from historical user-generated texts to infer their preferred topics, or leverage on an information propagation theory on networks to predict the topics of potential interest. However, jointly utilizing both the sources of data to provide a holistic prediction for such a task has not been exploited. We present a novel joint learning framework that takes advantage of both users' intrinsic (learned from their past social media postings) and extrinsic preference (learned from the social network influence) and that embeds them into low-dimensional space vectors. To facilitate effective learning, we encode latent continuous embedded vectors into binary ones via locality-sensitive hashing. Furthermore, to explain the predictions made by our \\\"black-box\\\" model, we investigate the importance of each training sample on the topic prediction performance of a testing instance to demonstrate its interpretability. The experiments conducted on datasets collected from several popular social media platforms demonstrate the effectiveness of our proposed method when compared with existing baselines.\",\n \"Title: ORACLE: Optimized Radio clAssification through Convolutional neuraL nEtworks.\\nYear: 2018\\n\\nAbstract: This paper describes the architecture and performance of ORACLE, an approach for detecting a unique radio from a large pool of bit-similar devices (same hardware, protocol, physical address, MAC ID) using only IQ samples at the physical layer. ORACLE trains a convolutional neural network (CNN) that balances computational time and accuracy, showing 99% classification accuracy for a 16-node USRP X310 SDR testbed and an external database of >100 COTS WiFi devices. Our work makes the following contributions: (i) it studies the hardware-centric features within the transmitter chain that causes IQ sample variations; (ii) for an idealized static channel environment, it proposes a CNN architecture requiring only raw IQ samples accessible at the front-end, without channel estimation or prior knowledge of the communication protocol; (iii) for dynamic channels, it demonstrates a principled method of feedback-driven transmitter-side modifications that uses channel estimation at the receiver to increase differentiability for the CNN classifier. The key innovation here is to intentionally introduce controlled imperfections on the transmitter side through software directives, while minimizing the change in bit error rate. Unlike previous work that imposes constant environmental conditions, ORACLE adopts the ‘train once deploy anywhere’ paradigm with near-perfect device classification accuracy.\",\n \"Title: Accelerating Deep Neural Network Training for Action Recognition on a Cluster of GPUs\\nYear: 2018\\n\\nAbstract: Due to the additional temporal dimension, large-scale video action recognition is even more challenging than image recognition and typically takes days to train on modern GPUs even for modest-sized datasets. We propose algorithms and techniques to accelerate training of deep neural networks for action recognition on a cluster of GPUs. In terms of convergence and scaling, our distributed training algorithm with adaptive batch size is provably superior to popular asynchronous stochastic gradient descent algorithms. The convergence analysis of our algorithm shows it is possible to reduce communication cost and at the same time minimize the number of iterations needed for convergence. We customize the Adam optimizer for our distributed algorithm to improve efficiency. In addition, we employ transfer-learning to further reduce training time while improving validation accuracy. Compared with the base-line single-GPU stochastic gradient descent implementation of the two-stream training approach, our implementation achieves super-linear speedups on 16 GPUs while improving validation accuracy. For the UCFI0l and HMDB51 datasets, the validation accuracies achieved are 93.1 % and 67.9% respectively. As far as we know, these are the highest accuracies achieved with the two-stream approach that does not involve computationally expensive 3D convolutions or pretraining on much larger datasets.\",\n \"Title: Shaping Gain of Lattices Based on Convolutional Codes and Construction A\\nYear: 2018\\n\\nAbstract: This paper studies the shaping gain and the performance-complexity trade-off of convolutional code lattices, lattices that are based on convolutional codes and Construction A. Generator polynomials for convolutional codes which provide the best-found shaping gain are presented, for various code rates, memory orders and lattice dimensions. Results are based on exhaustive searches. The obtained shaping gains usually exceed that of convolutional codes good for coding. Convolutional code lattices with memory order 7 can provide a shaping gain of 1.20 dB (up to a possible 1.53 dB theoretical maximum) at dimension 256, which is higher than the 1.03 dB shaping gain of the Leech lattice. While convolutional code lattices based on rate 1/2 convolutional codes have the best shaping gain for a fixed memory order, we show that using rate 1/3 convolutional codes produces a more favorable performance-complexity trade-off.\",\n \"Title: Doping Ag in ZnO Nanorods to Improve the Performance of Related Enzymatic Glucose Sensors.\\nYear: 2017\\n\\nAbstract: In this paper, the performance of a zinc oxide (ZnO) nanorod-based enzymatic glucose sensor was enhanced with silver (Ag)-doped ZnO (ZnO-Ag) nanorods. The effect of the doped Ag on the surface morphologies, wettability, and electron transfer capability of the ZnO-Ag nanorods, as well as the catalytic character of glucose oxidase (GOx) and the performance of the glucose sensor was investigated. The results indicate that the doped Ag slightly weakens the surface roughness and hydrophilicity of the ZnO-Ag nanorods, but remarkably increases their electron transfer ability and enhances the catalytic character of GOx. Consequently, the combined effects of the above influencing factors lead to a notable improvement of the performance of the glucose sensor, that is, the sensitivity increases and the detection limit decreases. The optimal amount of the doped Ag is determined to be 2 mM, and the corresponding glucose sensor exhibits a sensitivity of 3.85 A/(mMcm(2)), detection limit of 1.5 M, linear range of 1.5 x 10(-3)-6.5 mM, and Michaelis-Menten constant of 3.87 mM. Moreover, the glucose sensor shows excellent selectivity to urea, ascorbic acid, and uric acid, in addition to displaying good storage stability. These results demonstrate that ZnO-Ag nanorods are promising matrix materials for the construction of other enzymatic biosensors.\",\n \"Title: A Benchmark for Comparing Precision Medicine Methods in Thyroid Cancer Diagnosis using Tissue Microarrays.\\nYear: 2018\\n\\nAbstract: Motivation: The aim of precision medicine is to harness new knowledge and technology to optimize the timing and targeting of interventions for maximal therapeutic benefit. This study explores the possibility of building AI models without precise pixel-level annotation in prediction of the tumor size, extrathyroidal extension, lymph node metastasis, cancer stage and BRAF mutation in thyroid cancer diagnosis, providing the patients' background information, histopathological and immunohistochemical tissue images. Results: A novel framework for objective evaluation of automatic patient diagnosis algorithms has been established under the auspices of the IEEE International Symposium on Biomedical Imaging 2017-A Grand Challenge for Tissue Microarray Analysis in Thyroid Cancer Diagnosis. Here, we present the datasets, methods and results of the challenge and lay down the principles for future uses of this benchmark. The main contributions of the challenge include the creation of the data repository of tissue microarrays; the creation of the clinical diagnosis classification data repository of thyroid cancer; and the definition of objective quantitative evaluation for comparison and ranking of the algorithms. With this benchmark, three automatic methods for predictions of the five clinical outcomes have been compared, and detailed quantitative evaluation results are presented in this paper. Based on the quantitative evaluation results, we believe automatic patient diagnosis is still a challenging and unsolved problem.\",\n \"Title: QTCP: Adaptive Congestion Control with Reinforcement Learning\\nYear: 2019\\n\\nAbstract: Next generation network access technologies and Internet applications have increased the challenge of providing satisfactory quality of experience for users with traditional congestion control protocols. Efforts on optimizing the performance of TCP by modifying the core congestion control method depending on specific network architectures or apps do not generalize well under a wide range of network scenarios. This limitation arises from the rule-based design principle, where the performance is linked to a pre-decided mapping between the observed state of the network to the corresponding actions. Therefore, these protocols are unable to adapt their behavior in new environments or learn from experience for better performance. We address this problem by integrating a reinforcement-based Q-learning framework with TCP design in our approach called QTCP. QTCP enables senders to gradually learn the optimal congestion control policy in an on-line manner. QTCP does not need hard-coded rules, and can therefore generalize to a variety of different networking scenarios. Moreover, we develop a generalized Kanerva coding function approximation algorithm, which reduces the computation complexity of value functions and the searchable size of the state space. We show that QTCP outperforms the traditional rule-based TCP by providing 59.5% higher throughput while maintaining low transmission latency.\",\n \"Title: Janus: A Multi-TCP Framework for Application-Aware Optimization in Mobile Networks\\nYear: 2019\\n\\nAbstract: As the dominant protocol on the Internet, TCP has attracted significant attention and has been implemented in various ways, each of which optimizes for a single objective such as high throughput or low delay. However, in today's mobile networks that carry traffic from diverse types of flows, this approach may lead to misconfiguration of TCP congestion control algorithms and further degrade performance for many applications. In this paper, we propose Janus, a new transport-layer framework that automatically selects among existing congestion control variants to optimize traffic in accordance with application demands. Janus is easy to deploy because it reuses existing, well-tested congestion control implementations, and does not require any in-network or client-side changes. To explore the potential for this approach, we implement Janus in the Linux kernel and extensively evaluate its performance with both emulated and real Internet traffic. We show Janus outperforms alternative protocols by offering fast convergence times in response to changing network conditions, achieving 5-10X lower delay with comparable or higher throughput. Our approach also significantly improves user-perceived performance according to QoE metrics, with up to 5X fewer interruptions for video streaming applications and 2X faster page loading for web-browsing applications.\",\n \"Title: Decentralized robust optimal control for modular robot manipulators via critic-identifier structure-based adaptive dynamic programming\\nYear: 2020\\n\\nAbstract: This paper presents a decentralized robust optimal control method for modular robot manipulators (MRMs) via a critic-identifier structure-based adaptive dynamic programming (ADP) scheme. The robust control problem of MRMs is transformed into an optimal compensation control issue, which consists of model-based compensation control, identifier-based learning control and ADP-based optimal control. The dynamic model of MRMs is deployed for each joint module where the local dynamic information is utilized to design the model compensation controller. A neural network (NN) identifier is established to approximate the interconnected dynamic coupling. Based on ADP and local online policy iteration algorithm, the Hamiltonian–Jacobi–Bellman equation is solved by constructing a critic NN, and then the approximate optimal control policy derivation is possible. The closed-loop robotic system is asymptotic stable by the implementation of a set of developed decentralized control policies. Simulations are presented to demonstrate the effectiveness of the proposed method.\",\n \"Title: Robust visual tracking for planar objects using gradient orientation pyramid.\\nYear: 2019\\n\\nAbstract: Direct visual tracking (DVT) for planar objects is a fundamental problem in computer vision. DVT methods often formulate tracking as an image registration problem, where image intensities are directly used to match two images. However, these methods are usually sensitive to illumination changes as they assume intensities are constant. The gradient orientation (GO) was proven to be insensitive to illumination variations in previous reports. We further confirmed that the GO's robustness can be significantly improved when the pyramid technique is employed. We present a robust DVT method, named gradient orientation pyramid efficient second-order minimization (GOP-ESM), based on the proposed gradient orientation pyramid descriptor. GOP-ESM takes the advantages of the robust feature descriptors and the efficient second-order minimization method as to enhance tracking robustness and accuracy. We also published a tracking dataset for planar objects with illumination changes (POIC). The evaluations on the proposed POIC dataset and the other two public benchmark datasets demonstrated that GOP-ESM outperforms the state-of-the-art tracking methods against various environmental variations, especially illumination changes. (C) 2019 SPIE and IS&T\",\n \"Title: Animated Mesh Simplification Based On Motion Features In Visual Sensor Networks\\nYear: 2019\\n\\nAbstract: The three-dimensional animated model is widely used in scientific visualization, entertainment, and virtual applications, especially in visual sensor networks. The main purpose of simplification is to capture the shape sequence of an object with very few elements while preserving the overall shape. As three-dimensional animated mesh is time-varying in all frames, the trade-off between the temporal coherence and geometric distortion must be considered to develop simplification algorithm. In this article, a novel three-dimensional animated mesh simplification algorithm based on motion features is presented. Here, motion features are the connection areas of the relative movement consisted of vertices and edges. Motion feature extraction is to find a subgraph that has movement property. Dihedral angle of the edge through all frames is used to determine whether an edge is connected or not to the movement parts. Then, a rotation connected graph is defined to extract motion features. Traveling this graph, all motion features can be extracted. Based on the motion features, animated quadric error metric is created and quadric error matrix is built through all frames. Compared with the other methods, the important advantages of this method are high-efficiency simplification process and smoother simplification effects. It is suitable to be used in real-time applications. Experiment results show that the 3D animated mesh simplification effects by our method are satisfactory.\",\n \"Title: Conditional progressive network for clothing parsing.\\nYear: 2019\\n\\nAbstract: Clothing parsing is significant to many clothing applications. Recently, a lot of clothing parsing methods have been presented, which explore the innovation of the parsing pipeline or try to find more specific prior information. Although these methods perform well in some benchmarks, a few challenging problems have not been solved yet, such as the complicated mutual interference among labels. In this study, the authors propose a Conditional Progressive Network to parse clothing in different scales and prevent the mutual interference among labels. The authors’ solution consists of three sub-networks, including Conditional Parsing Network (CPN), Pose Estimation Network (PEN) and Label Transform Network (LTN). Specifically, the CPN module generates the intermediate parsing result in the form of the multiple progressive stages, which combines with the previous outputs in each stage and the specific prior conditions. The PEN module provides a series of heat maps about the human pose information. The LTN module suppresses the redundant labels to avoid the mutual interference among labels. They demonstrate their solution in parsing the fashion clothing cases on the ATR and the Fashion dataset. In their experiments, their method obtains a better performance than the state-of-the-art methods.\",\n \"Title: Variational Session-based Recommendation Using Normalizing Flows\\nYear: 2019\\n\\nAbstract: We present a novel generative Session-Based Recommendation (SBR) framework, called VAriational SEssion-based Recommendation (VASER) - a non-linear probabilistic methodology allowing Bayesian inference for flexible parameter estimation of sequential recommendations. Instead of directly applying extended Variational AutoEncoders (VAE) to SBR, the proposed method introduces normalizing flows to estimate the probabilistic posterior, which is more effective than the agnostic presumed prior approximation used in existing deep generative recommendation approaches. VASER explores soft attention mechanism to upweight the important clicks in a session. We empirically demonstrate that the proposed model significantly outperforms several state-of-the-art baselines, including the recently-proposed RNN/VAE-based approaches on real-world datasets.\",\n \"Title: Context-aware Variational Trajectory Encoding and Human Mobility Inference\\nYear: 2019\\n\\nAbstract: Unveiling human mobility patterns is an important task for many downstream applications like point-of-interest (POI) recommendation and personalized trip planning. Compelling results exist in various sequential modeling methods and representation techniques. However, discovering and exploiting the context of trajectories in terms of abstract topics associated with the motion can provide a more comprehensive understanding of the dynamics of patterns. We propose a new paradigm for moving pattern mining based on learning trajectory context, and a method - Context-Aware Variational Trajectory Encoding and Human Mobility Inference (CATHI) - for learning user trajectory representation via a framework consisting of: (1) a variational encoder and a recurrent encoder; (2) a variational attention layer; (3) two decoders. We simultaneously tackle two subtasks: (T1) recovering user routes (trajectory reconstruction); and (T2) predicting the trip that the user would travel (trajectory prediction). We show that the encoded contextual trajectory vectors efficiently characterize the hierarchical mobility semantics, from which one can decode the implicit meanings of trajectories. We evaluate our method on several public datasets and demonstrate that the proposed CATHI can efficiently improve the performance of both subtasks, compared to state-of-the-art approaches.\",\n \"Title: Improving Top-K Recommendation via JointCollaborative Autoencoders\\nYear: 2019\\n\\nAbstract: In this paper, we propose a Joint Collaborative Autoencoder framework that learns both user-user and item-item correlations simultaneously, leading to a more robust model and improved top-K recommendation performance. More specifically, we show how to model these user-item correlations and demonstrate the importance of careful normalization to alleviate the influence of feedback heterogeneity. Further, we adopt a pairwise hinge-based objective function to maximize the top-K precision and recall directly for top-K recommenders. Finally, a mini-batch optimization algorithm is proposed to train the proposed model. Extensive experiments on three public datasets show the effectiveness of the proposed framework over state-of-the-art non-neural and neural alternatives.\",\n \"Title: Predicting Human Mobility via Variational Attention\\nYear: 2019\\n\\nAbstract: An important task in Location based Social Network applications is to predict mobility - specifically, user's next point-of-interest (POI) - challenging due to the implicit feedback of footprints, sparsity of generated check-ins, and the joint impact of historical periodicity and recent check-ins. Motivated by recent success of deep variational inference, we propose VANext (Variational Attention based Next) POI prediction: a latent variable model for inferring user's next footprint, with historical mobility attention. The variational encoding captures latent features of recent mobility, followed by searching the similar historical trajectories for periodical patterns. A trajectory convolutional network is then used to learn historical mobility, significantly improving the efficiency over often used recurrent networks. A novel variational attention mechanism is proposed to exploit the periodicity of historical mobility patterns, combined with recent check-in preference to predict next POIs. We also implement a semi-supervised variant - VANext-S, which relies on variational encoding for pre-training all current trajectories in an unsupervised manner, and uses the latent variables to initialize the current trajectory learning. Experiments conducted on real-world datasets demonstrate that VANext and VANext-S outperform the state-of-the-art human mobility prediction models.\",\n \"Title: A Distributed Hierarchical SGD Algorithm with Sparse Global Reduction.\\nYear: 2019\\n\\nAbstract: Reducing communication overhead is a big challenge for large-scale distributed training. To address this issue, we present a hierarchical averaging stochastic gradient descent (Hier-AVG) algorithm that reduces global reductions (averaging) by employing less costly local reductions. As a very general type of parallel SGD, Hier-AVG can reproduce several commonly adopted synchronous parallel SGD variants by adjusting its parameters. We establish standard convergence results of Hier-AVG for non-convex smooth optimization problems. Under the non-asymptotic scenario, we show that Hier-AVG with less frequent global averaging can sometimes have faster training speed. In addition, we show that more frequent local averaging with more participants involved can lead to faster training convergence. By comparing Hier-AVG with another distributed training algorithm K-AVG, we show that through deploying local averaging with less global averaging Hier-AVG can still achieve comparable training speed while constantly get better test accuracy. As a result, local averaging can serve as an alternative remedy to effectively reduce communication overhead when the number of learners is large. We test Hier-AVG with several state-of-the-art deep neural nets on CIFAR-10 to validate our analysis. Further experiments to compare Hier-AVG with K-AVG on ImageNet-1K also show Hier-AVGu0027s superiority over K-AVG.\",\n \"Title: Design of Low-Complexity 3-D Underwater Imaging System With Sparse Planar Arrays\\nYear: 2019\\n\\nAbstract: The development of a real-time 3-D underwater imaging system with a planar array is restricted by the huge hardware cost and computational burden associated with the large number of elements required. In this paper, a new design of low-complexity 3-D underwater imaging system is proposed, involving two key parts: a special sparse array with low hardware cost and an efficient beamforming with low c...\",\n \"Title: The Sup-norm Perturbation of HOSVD and Low Rank Tensor Denoising\\nYear: 2019\\n\\nAbstract: The higher order singular value decomposition (HOSVD) of tensors is a generalization of matrix SVD. The perturbation analysis of HOSVD under random noise is more delicate than its matrix counterpart. Recently, polynomial time algorithms have been proposed where statistically optimal estimates of the singular subspaces and the low rank tensors are attainable in the Euclidean norm. In this article, we analyze the sup-norm perturbation bounds of HOSVD and introduce estimators of the singular subspaces with sharp deviation bounds in the sup-norm. We also investigate a low rank tensor denoising estimator and demonstrate its fast convergence rate with respect to the entry-wise errors. The sup-norm perturbation bounds reveal unconventional phase transitions for statistical learning applications such as the exact clustering in high dimensional Gaussian mixture model and the exact support recovery in sub-tensor localizations. In addition, the bounds established for HOSVD also elaborate the one-sided sup-norm perturbation bounds for the singular subspaces of unbalanced (or fat) matrices.\",\n \"Title: Disentangled Network Alignment with Matching Explainability\\nYear: 2019\\n\\nAbstract: Network alignment (NA) is a fundamental problem in many application domains – from social networks, through biology and communications, to neuroscience. The main objective is to identify common nodes and most similar connections across multiple networks (resp. graphs). Many of the existing efforts focus on efficient anchor node linkage by leveraging various features and optimizing network mapping functions with the pairwise similarity between anchor nodes. Despite the recent advances, there still exist two kinds of challenges: (1) entangled node embeddings, arising from the contradictory goals of NA: embedding proximal nodes in a closed form for representation in a single network vs. discriminating among them when mapping the nodes across networks; and (2) lack of interpretability about the node matching and alignment, essential for understanding prediction tasks. We propose d NAME (disentangled Network Alignment with Matching Explainability) – a novel solution for NA in heterogeneous networks settings, based on a matching technique that embeds nodes in a disentangled and faithful manner. The NA task is cast as an adversarial optimization problem which learns a proximity-preserving model locally around the anchor nodes, while still being discriminative. We also introduce a method to explain our semi-supervised model with the theory of robust statistics, by tracing the importance of each anchor node and its explanations on the NA performance. This is extensible to many other NA methods, as it provides model interpretability. Experiments conducted on several public datasets show that d NAME outperforms the state-of-the-art methods in terms of both network alignment precision and node matching ranking.\",\n \"Title: Meta-GNN: On Few-shot Node Classification in Graph Meta-learning.\\nYear: 2019\\n\\nAbstract: Meta-learning has received a tremendous recent attention as a possible approach for mimicking human intelligence, i.e., acquiring new knowledge and skills with little or even no demonstration. Most of the existing meta-learning methods are proposed to tackle few-shot learning problems such as image and text, in rather Euclidean domain. However, there are very few works applying meta-learning to non-Euclidean domains, and the recently proposed graph neural networks (GNNs) models do not perform effectively on graph few-shot learning problems. Towards this, we propose a novel graph meta-learning framework -- Meta-GNN -- to tackle the few-shot node classification problem in graph meta-learning settings. It obtains the prior knowledge of classifiers by training on many similar few-shot learning tasks and then classifies the nodes from new classes with only few labeled samples. Additionally, Meta-GNN is a general model that can be straightforwardly incorporated into any existing state-of-the-art GNN. Our experiments conducted on three benchmark datasets demonstrate that our proposed approach not only improves the node classification performance by a large margin on few-shot learning problems in meta-learning paradigm, but also learns a more general and flexible model for task adaption.\",\n \"Title: Information Diffusion Prediction via Recurrent Cascades Convolution\\nYear: 2019\\n\\nAbstract: Effectively predicting the size of an information cascade is critical for many applications spanning from identifying viral marketing and fake news to precise recommendation and online advertising. Traditional approaches either heavily depend on underlying diffusion models and are not optimized for popularity prediction, or use complicated hand-crafted features that cannot be easily generalized to different types of cascades. Recent generative approaches allow for understanding the spreading mechanisms, but with unsatisfactory prediction accuracy. To capture both the underlying structures governing the spread of information and inherent dependencies between re-tweeting behaviors of users, we propose a semi-supervised method, called Recurrent Cascades Convolutional Networks (CasCN), which explicitly models and predicts cascades through learning the latent representation of both structural and temporal information, without involving any other features. In contrast to the existing single, undirected and stationary Graph Convolutional Networks (GCNs), CasCN is a novel multi-directional/dynamic GCN. Our experiments conducted on real-world datasets show that CasCN significantly improves the prediction accuracy and reduces the computational cost compared to state-of-the-art approaches.\",\n \"Title: Motion Based Inference of Social Circles via Self-Attention and Contextualized Embedding.\\nYear: 2019\\n\\nAbstract: Extracting knowledge from human mobility data is an important task for many downstream applications such as point-of-interest recommendation, motion trace identification, and personalized trip planning. A specific problem that has recently spurred research interest is the so-called Social Circle Inference from Mobility data (SCIM), aiming at inferring relationships among users based on mobility data and without any explicit structured network information. The existing methods either require partial social ties or fail to model the implicit correlations between user links, thereby suffering from critical inference bias. We present a novel SCIM framework, called SCIM via self-Attention and Contextualizedembedding (SCIMAC) - a methodology capturing multiple aspects of users' check-in behavior and complex motion patterns of different users. Instead of directly applying the recurrent model on training user trajectories, the proposed method introduces a new module for context-aware check-in representation learning by adaptively incorporating the internal states of the recurrent layers, which is more effective than the context-independent check-in embedding used in existing social circle inference approaches. To model the underlying correlations between labels, SCIMAC leverages a more sophisticated label embedding technique to adjust the penalties for correlated users, enabling a better understanding of the user's hierarchy in the label space, and alleviating the inference bias. We empirically demonstrate that our SCIMAC model significantly outperforms several state-of-the-art baselines on real-world datasets.\",\n \"Title: Quantifying Layerwise Information Discarding of Neural Networks.\\nYear: 2019\\n\\nAbstract: This paper presents a method to explain how input information is discarded through intermediate layers of a neural network during the forward propagation, in order to quantify and diagnose knowledge representations of pre-trained deep neural networks. We define two types of entropy-based metrics, i.e., the strict information discarding and the reconstruction uncertainty, which measure input information of a specific layer from two perspectives. We develop a method to enable efficient computation of such entropy-based metrics. Our method can be broadly applied to various neural networks and enable comprehensive comparisons between different layers of different networks. Preliminary experiments have shown the effectiveness of our metrics in analyzing benchmark networks and explaining existing deep-learning techniques.\",\n \"Title: Decentralized Robust Optimal Control For Modular Robot Manipulators Based On Zero-Sum Game With Adp\\nYear: 2019\\n\\nAbstract: In this paper, a decentralized robust zero-sum optimal control method is proposed for modular robot manipulators (MRMs) based on the adaptive dynamic programming (ADP) approach. The dynamic model of MRMs is formulated via joint torque feedback (JTF) technique that is deployed for each joint module, in which the local dynamic information is used to design the model compensation controller. An uncertainty decomposition-based robust control is developed to compensate the model uncertainties, and then the robust optimal control problem of MRMs with uncertain environments can be transformed into a two-player zero-sum optimal control one. According to the ADP algorithm, the Hamilton-Jacobi-Isaacs (HJI) equation is solved by constructing actioncritic neural networks (NNs) and then the approximate optimal control policy derivation is possible. Experiments are conducted to verify the effectiveness of the proposed method.\",\n \"Title: Active Optimal Fault-Tolerant Control Method For Multi-Fault Concurrent Modular Manipulator Based On Adaptive Dynamic Programming\\nYear: 2019\\n\\nAbstract: In this paper, a novel active optimal fault-tolerant control (FTC) scheme is designed based on adaptive dynamic programming (ADP) for modular manipulator when sensor and actuator faults are concurrency. Firstly, the sensor fault is transformed into the pseudo-actuator fault by constructing a nonlinear transformation with diffeomorphism theory. Secondly, the faults estimated by the adaptive fault observer are applied to establish an improved performance index function. Next, the online policy iteration (PI) algorithm is used to solve the Hamilton-Jacobi-Bellman (HJB) equation via establishing a critic neural network. The optimal fault-tolerant controller is proved to be uniformly ultimately bounded (UUB) based on Lyapunov stable theory. Finally, the effectiveness of the proposed multi-fault-tolerant control algorithm is verified by simulation results.\",\n \"Title: Information Cascades Modeling via Deep Multi-Task Learning\\nYear: 2019\\n\\nAbstract: Effectively modeling and predicting the information cascades is at the core of understanding the information diffusion, which is essential for many related downstream applications, such as fake news detection and viral marketing identification. Conventional methods for cascade prediction heavily depend on the hypothesis of diffusion models and hand-crafted features. Owing to the significant recent successes of deep learning in multiple domains, attempts have been made to predict cascades by developing neural networks based approaches. However, the existing models are not capable of capturing both the underlying structure of a cascade graph and the node sequence in the diffusion process which, in turn, results in unsatisfactory prediction performance. In this paper, we propose a deep multi-task learning framework with a novel design of shared-representation layer to aid in explicitly understanding and predicting the cascades. As it turns out, the learned latent representation from the shared-representation layer can encode the structure and the node sequence of the cascade very well. Our experiments conducted on real-world datasets demonstrate that our method can significantly improve the prediction accuracy and reduce the computational cost compared to state-of-the-art baselines.\",\n \"Title: Reducing global reductions in large-scale distributed training\\nYear: 2019\\n\\nAbstract: Current large-scale training of deep neural networks typically employs synchronous stochastic gradient descent that incurs large communication overhead. Instead of optimizing reduction routines as done in recent studies, we propose algorithms that do not require frequent global reductions. We first show that reducing the global reduction frequency works as an effective regularization technique that improves generalization of adaptive optimizers. We then propose an algorithm that reduces the global reduction frequency by employing local reductions on a subset of learners. In addition, to maximize the effect of reduction on convergence, we introduce reduction momentum that further accelerates convergence.\\n\\nOur experiment with the CIFAR-10 dataset shows that for the K-step averaging algorithm extremely sparse reductions help bridge the generalization gap. With 6 GPUs, in comparison to regular synchronous implementations, our implementation reduces more than 99% of global reductions. Further, we show that with 32 GPUs, our implementation reduces the number of global reductions by half. Experimenting with the ImageNet-1K dataset, we show that combining local reductions with global reductions and applying reduction momentum can further reduce global reductions by up to 62% for the same validation accuracy achieved in comparison to K-step averaging. With 400 GPUs global reduction frequency is reduced to once per 102K samples.\",\n \"Title: Hybrid graph convolutional networks with multi-head attention for location recommendation\\nYear: 2020\\n\\nAbstract: Recommending yet-unvisited points of interest (POIs) which may be of interest to users is one of the fundamental applications in location-based social networks. It mainly replies on the understanding of users, POIs, and their interactions. Previous studies either develop matrix factorization-based approaches or utilize deep learning frameworks to learn better representation of users and POIs in order to estimate users' latent preference. However, most of existing methods still confront the challenges like in traditional recommender systems, such as data sparsity and cold-start. In particular, they have difficulties in fully utilizing rich semantic information, such as social influence, geographical constraints and interactions between users and POIs. To fill this research gap, we propose a new recommendation framework - Hybrid Graph convolutional networks with Multi-head Attention for POI recommendation (HGMAP). HGMAP constructs a spatial graph based on the geographical distance between pairs of POIs and leverages Graph Convolutional Networks (GCNs) to express the high-order connectivity among POIs, which not only incorporates the spatial constraints but also provides an effective way to alleviate the sparse check-in problem. In addition, HGMAP exploits the user social relationship with another GCN and differentiates user preference over different aspects of POIs with a multi-head attention mechanism. We conducted extensive experiments on three public datasets and the results demonstrate that HGMAP significantly improves the recommendation performance over several state-of-the-art models, for example, up to approximately 4.8% and 7% forPrecision@10andRecall@10, respectively.\",\n \"Title: Multi-Task Learning By Leveraging The Semantic Information\\nYear: 2021\\n\\nAbstract: One crucial objective of multi-task learning is to align distributions across tasks so that the information between them can be transferred and shared. However, existing approaches only focused on matching the marginal feature distribution while ignoring the semantic information, which may hinder the learning performance. To address this issue, we propose to leverage the label information in multi-task learning by exploring the semantic conditional relations among tasks. We first theoretically analyze the generalization bound of multi-task learning based on the notion of Jensen-Shannon divergence, which provides new insights into the value of label information in multi-task learning. Our analysis also leads to a concrete algorithm that jointly matches the semantic distribution and controls label distribution divergence. To confirm the effectiveness of the proposed method, we first compare the algorithm with several baselines on some benchmarks and then test the algorithms under label space shift conditions. Empirical results demonstrate that the proposed method could outperform most baselines and achieve state-of-the-art performance, particularly showing the benefits under the label shift conditions.\",\n \"Title: Overcoming Catastrophic Forgetting In Graph Neural Networks With Experience Replay\\nYear: 2021\\n\\nAbstract: Graph Neural Networks (GNNs) have recently received significant research attention due to their superior performance on a variety of graph-related learning tasks. Most of the current works focus on either static or dynamic graph settings, addressing a single particular task, e.g., node/graph classification, link prediction. In this work, we investigate the question: can GNNs be applied to continuously learning a sequence of tasks? Towards that, we explore the Continual Graph Learning (CGL) paradigm and present the Experience Replay based framework ER-GNN for CGL to alleviate the catastrophic forgetting problem in existing GNNs. ER-GNN stores knowledge from previous tasks as experiences and replays them when learning new tasks to mitigate the catastrophic forgetting issue. We propose three experience node selection strategies: mean of feature, coverage maximization, and influence maximization, to guide the process of selecting experience nodes. Extensive experiments on three benchmark datasets demonstrate the effectiveness of our ER-GNN and shed light on the incremental graph (non-Euclidean) structure learning.\",\n \"Title: Portraying Citizens' Occupations And Assessing Urban Occupation Mixture With Mobile Phone Data: A Novel Spatiotemporal Analytical Framework\\nYear: 2021\\n\\nAbstract: Mobile phone data is a typical type of big data with great potential to explore human mobility and individual portrait identification. Previous studies in population classifications with mobile phone data only focused on spatiotemporal mobility patterns and their clusters. In this study, a novel spatiotemporal analytical framework with an integration of spatial mobility patterns and non-spatial behavior, through smart phone APP (applications) usage preference, was proposed to portray citizens' occupations in Guangzhou center through mobile phone data. An occupation mixture index (OMI) was proposed to assess the spatial patterns of occupation diversity. The results showed that (1) six types of typical urban occupations were identified: financial practitioners, wholesalers and sole traders, IT (information technology) practitioners, express staff, teachers, and medical staff. (2) Tianhe and Yuexiu district accounted for most employed population. Wholesalers and sole traders were found to be highly dependent on location with the most obvious industrial cluster. (3) Two centers of high OMI were identified: Zhujiang New Town CBD and Tianhe Smart City (High-Tech Development Zone). It was noted that CBD has a more profound effect on local as well as nearby OMI, while the scope of influence Tianhe Smart City has on OMI is limited and isolated. This study firstly integrated both spatial mobility and non-spatial behavior into individual portrait identification with mobile phone data, which provides new perspectives and methods for the management and development of smart city in the era of big data.\",\n \"Title: Trajectory-User Linking via Graph Neural Network\\nYear: 2021\\n\\nAbstract: Trajectory-User Linking (TUL) refers to classifying trajectories into the corresponding generated users and has emerged as an essential spatio-temporal data mining task with a broad spectrum of applications, ranging from personalized location recommendation and trip planning to criminal behavior detection and object tracking. Despite the progress made by recent deep learning-based human mobility learning models, some critical factors related to personal context and user-location interactions have not yet been fully explored. Besides, existing works suffer from high computational cost issues due to the increased complexity of trajectory learning and contextual location embedding. In this work, we propose a novel end-to-end model called GNNTUL, composed of a graph neural network (GNN) module and a classifier, to effectively and efficiently learn human mobility and associate the traces to the users in online social networks. GNNTUL is the first GNN-based human mobility learning model exploiting implicit transition patterns behind sparse user traces in online social networks while extracting users' unique motion features and discriminating the motion traces. Extensive experiments conducted on two real-world datasets demonstrate the superiority of GNNTUL over several state-of-the-art baselines in terms of both linking accuracy and learning efficiency.\",\n \"Title: Catch me if you can: A participant-level rumor detection framework via fine-grained user representation learning\\nYear: 2021\\n\\nAbstract: Researchers have exerted tremendous effort in designing ways to detect and identify rumors automatically. Traditional approaches focus on feature engineering. They require lots of human actions and are difficult to generalize. Deep learning solutions come to help. However, they usually fail to capture the underlying structure of the rumor propagation and the influence of all participants involved in the spreading chain. In this study, we propose a novel participant-level rumor detection framework. It explicitly models and integrates various fine-grained user representations (i.e., user influence, susceptibility, and temporal information) of all participants from the propagation threads via deep representation learning. Experiments conducted on real-world datasets demonstrate a significant accuracy improvement of our approach. Theoretically, we contribute to the effective usage of data science and analytics for social information diffusion design, particularly rumor detection. Practically, our results can be used to improve the quality of rumor detection services for social platforms.\",\n \"Title: TRAFFIC SPEED FORECASTING VIA SPATIO-TEMPORAL ATTENTIVE GRAPH ISOMORPHISM NETWORK\\nYear: 2021\\n\\nAbstract: Traffic forecasting is of particular interest in intelligent transportation systems (ITS). This problem is challenging owing to the complicated spatio-temporal dependencies between different areas in a road sensor network. Previous approaches have applied various deep learning methods for traffic forecasting, e.g., leveraging graph convolutional networks (GCNs) for spatial correlation modeling and utilizing recurrent neural networks (RNNs) to capture temporal traffic evolutions. However, the existing GCN-based models can not adequately distinguish the non-Euclidean topological structure of road traffic and are easily affected by random traffic noise. This work proposes an end-to-end framework to capture spatial dependencies through graph isomorphism network, while explicitly taking network topologic similarities into account and leveraging symmetric traffic for learning the traffic conditions. Extensive experiments on two real-world traffic datasets demonstrate the superiority of our proposed approach.\",\n \"Title: INFERRING HIGH-RESOLUTIONAL URBAN FLOW WITH INTERNET OF MOBILE THINGS\\nYear: 2021\\n\\nAbstract: Monitoring urban flow timely and accurately is crucial for many industrial applications - from urban planning to traffic control in the smart cities. This work introduces a new method for inferring fine-grained urban flow with the internet of mobile things such as taxis and bikes. We tackle the problem from a new perspective and present a novel deep learning method UrbanODE (Urban flow inference with Neural Ordinary Differential Equations). Furthermore, UrbanODE provides a flexible balance between flow inference accuracy and computational efficiency, which is important in computation restricted scenarios such as pervasive edge computing. Extensive evaluations on real-world traffic flow data demonstrate the superiority of the proposed method.\",\n \"Title: PROBABILISTIC GRAPH NEURAL NETWORKS FOR TRAFFIC SIGNAL CONTROL\\nYear: 2021\\n\\nAbstract: Intelligent traffic signal control is crucial for efficient transportation systems. Recent studies use reinforcement learning (RL) to coordinate traffic signals and improve traffic signal cooperation. However, they either design the state of agents in a heuristic manner or model traffic dynamics in a deterministic way. This work presents a variational graph learning model TSC-GNN (Traffic Signal Control via probabilistic Graph Neural Networks) to learn the latent representations of agents and generate Q-value while taking traffic uncertainty conditions into account. Besides, we explain the rationality behind our state design using transportation theory. Experimental results conducted on real-world datasets demonstrate our model's superiority, e.g., it achieves more than 8% traffic efficiency improvement compared with the state-of-the-art baselines.\",\n \"Title: Towards Predicting Vehicular Data Consumption\\nYear: 2021\\n\\nAbstract: Combining in-car multiple sensors measuring parameters that can be used to improve both safety and efficiency with a plethora of external data sources (e.g., traffic conditions, weather) which, if properly used, can significantly improve the overall trip experience. One source that can help the navigation and provide "context awareness", especially for autonomous driving, are the High Definition (...\",\n \"Title: Analysis Of Propagation And Distribution Characteristics Of Leakage Acoustic Waves In Water Supply Pipelines\\nYear: 2021\\n\\nAbstract: Leakage detection methods based on the analysis of leakage acoustic signals provide an effective technical approach for detecting small leaks in water supply pipelines. From a technical perspective, the study of the propagation characteristics of acoustic waves generated by the leakage in the water supply pipeline is necessary for detecting the leak location on the basis of acoustic signals. In this study, a 3D transient leakage acoustic wave propagation equation was derived by combining the principles of fluid dynamics and Lighthill acoustic analogy theory. The propagation of the leakage-induced noise in water supply pipeline was modelled theoretically. We simulated the propagation of a leakage acoustic wave under different conditions for different target scenarios encountered in actual pipeline inspections. Specifically, we analysed the effect of different factors, such as the pipe size and acoustic source characteristics, on acoustic propagation. Finally, the simulated experiments were practically performed using a self-designed simulated water supply pipeline and self-developed spherical water supply pipeline detector to validate the simulation analysis. The results of this study provide a theoretical guidance and basis for the analysis of characteristics of leakage acoustic wave signals and the recognition of leakage conditions in water supply pipelines.\",\n \"Title: Self-supervised human mobility learning for next location prediction and trajectory classification\\nYear: 2021\\n\\nAbstract: AbstractAbstractMassive digital mobility data are accumulated nowadays due to the proliferation of location-based service (LBS), which provides the opportunity of learning knowledge from human traces that can benefit a range of business and management applications, such as location recommendation, anomaly trajectory detection, crime discrimination, and epidemic tracing. However, human mobility data is usually sporadically updated since people may not frequently access mobile apps or publish the geo-tagged contents. Consequently, distilling meaningful supervised signals from sparse and noisy human mobility is the main challenge of existing models. This work presents a Self-supervised Mobility Learning (SML) framework to encode human mobility semantics and facilitate the downstream location-based tasks. SML is designed for modeling sparse and noisy human mobility trajectories, focusing on leveraging rich spatio-temporal contexts and augmented traces to improve the trajectory representations. It provides a principled way to characterize the inherent movement correlations while tackling the implicit feedback and weak supervision problems in existing model-based approaches. Besides, contrastive instance discrimination is first introduced for spatio-temporal data training by explicitly distinguishing the real user check-ins from the negative samples that tend to be wrongly predicted. Extensive experiments on two practical applications, i.e., location prediction and trajectory classification, demonstrate that our method can significantly improve the location-based services over the state-of-the-art baselines.\",\n \"Title: Modeling Microscopic And Macroscopic Information Diffusion For Rumor Detection\\nYear: 2021\\n\\nAbstract: Researchers have exerted tremendous effort in designing ways to detect and identify rumors automatically. Traditional approaches focus on feature engineering, which requires extensive manual efforts and are difficult to generalize to different domains. Recently, deep learning solutions have emerged as the de facto methods which detect online rumors in an end-to-end manner. However, they still fail to fully capture the dissemination patterns of rumors. In this study, we propose a novel diffusion-based rumor detection model, called Macroscopic and Microscopic-aware Rumor Detection, to explore the full-scale diffusion patterns of information. It leverages graph neural networks to learn the macroscopic diffusion of rumor propagation and capture microscopic diffusion patterns using bidirectional recurrent neural networks while taking into account the user-time series. Moreover, it leverages knowledge distillation technique to create a more informative student model and further improve the model performance. Experiments conducted on two real-world data sets demonstrate that our method achieves significant accuracy improvements over the state-of-the-art baseline models on rumor detection.\",\n \"Title: PeriodicMove: Shift-aware Human Mobility Recovery with Graph Neural Network\\nYear: 2021\\n\\nAbstract: ABSTRACTHuman mobility recovery is of great importance for a wide range of location-based services. However, recovering human mobility is not trivial because of three challenges: 1) complex transition patterns among locations; 2) multi-level periodicity and shifting periodicity of human mobility; 3) sparsity of the collected trajectory data. In this paper, we propose PeriodicMove, a neural attention model based on graph neural network for human mobility recovery from lengthy and sparse trajectories. In PeriodicMove, we first construct a directed graph for each trajectory and capture complex location transition patterns using graph neural network. Then, we design two attention mechanisms which capture multi-level periodicity and shifting periodicity of human mobility respectively. Finally, a spatial-aware loss function is proposed to incorporate spatial proximity into the model optimization, which alleviates the data sparsity problem. We perform extensive experiments and the evaluation results demonstrate that PeriodicMove yields significant improvements over the competitors on two representative real-life mobility datasets. In addition, by providing high-quality mobility data, our model can benefit a variety of mobility-oriented downstream applications.\",\n \"Title: Vector-Quantized Autoencoder With Copula for Collaborative Filtering\\nYear: 2021\\n\\nAbstract: BSTRACTIn theory, the variational auto-encoder (VAE) is not suitable for recommendation tasks, although it has been successfully utilized for collaborative filtering (CF) models. In this paper, we propose a Gaussian Copula-Vector Quantized Autoencoder (GC-VQAE) model that differs prior arts in two key ways: (1) Gaussian Copula helps to model the dependencies among latent variables which are used to construct a more complex distribution compared with the mean-field theory; and (2) by incorporating a vector quantisation method into encoders our model can learn discrete representations which are consistent with the observed data rather than directly sampling from the simple Gaussian distributions. Our approach is able to circumvent the \\\"posterior collapse'' issue and break the prior constraint to improve the flexibility of latent vector encoding and learning ability. Empirically, GC-VQAE can significantly improve the recommendation performance compared to existing state-of-the-art methods.\",\n \"Title: MVSN: A Multi-view stack network for human parsing\\nYear: 2021\\n\\nAbstract: The human parsing task is dedicated to allocating pixel-level fine-grained semantic labels. However, recent solutions are limited to fully utilize the prior information (poses and edges) and the potential information of the image data, remaining problems with ambiguous boundaries, incomplete human parts, and redundant labels. To solve the above problems, we propose a novel Multi-view Stack Network (MVSN), which is constructed by three stacks with multiple views of features included parts, edges, and pre-segmentation. Meanwhile, a channel correlator is developed to acquire the correlation between local and global information better. Comprehensive experiments and corresponding results on three public datasets show that the proposed MVSN performs favorably against the state-of-the-art methods.\",\n \"Title: Forecasting Reservoir Inflow Via Recurrent Neural Odes\\nYear: 2021\\n\\nAbstract: Forecasting reservoir inflow is critical for making many policies, ranging from flood control and agriculture irrigation to water ecology management, hydropower generation, and landslide prevention. Prior studies mainly exploit autoregressive models - e.g., recurrent neural networks (RNN) and its many variants - to model the flow time series's temporal pattern. However, existing approaches rely on regular and accurate inflow observations, which either fail to predict multiscale inflow (e.g., an hour, a day, or a month ahead prediction) or ignore the uncertainty of observations due to confounding factors such as snowmelt and precipitation. To address the limitations, we propose a novel inflow forecasting model by incorporating the uncertainty of the observations into the RNN model and the continuous-time dynamics of the latent states with neural ordinary differential equations (ODE). Our method, called FlowODE, explicitly encodes the stochasticity of hidden conditions in addition to the temporal dependencies among inflow observations. Moreover, FlowODE explores a continuum of layers instead of discrete RNNs to model the hidden states' dynamics, allowing us to infer the inflow at any time horizon flexibly. We conduct extensive experiments on the real-world datasets collected from two large-scale hydropower dams. The results show that our method consistently outperforms previous inflow forecasting models while providing adaptable predictions and a flexible balance between prediction accuracy and computational cost.\",\n \"Title: Land Deformation Prediction Via Slope-Aware Graph Neural Networks\\nYear: 2021\\n\\nAbstract: We introduce a slope-aware graph neural network (SA-GNN) to leverage continuously monitored data and predict the land displacement. Unlike general GNNs tackling tasks in the plain graphs, our method is capable of generalizing 3D spatial knowledge from InSAR point clouds. Specifically, we structure of the land surface, while preserving the spatial correlations among adjacent points. The point cloud can then be efficiently converted to a near-neighbor graph where general GNN methods can be applied to predict the displacement of the slope surface. We conducted experiments on real-world datasets and the results demonstrate that SA-GNN outperforms existing 3D CNN and point GNN methods.\",\n \"Title: Rate-Optimal Subspace Estimation on Random Graphs.\\nYear: 2021\\n\\nAbstract: Use the \\\"Report an Issue\\\" link to request a name change.\",\n \"Title: Spatial Distribution and Mechanism of Urban Occupation Mixture in Guangzhou: An Optimized GeoDetector-Based Index to Compare Individual and Interactive Effects\\nYear: 2021\\n\\nAbstract: Numerous studies have been devoted to uncovering the characteristics of resident density and urban mobility with multisource geospatial big data. However, little attention has been paid to the internal diversity of residents such as their occupations, which is a crucial aspect of urban vibrancy. This study aims to investigate the variation between individual and interactive influences of built environment factors on occupation mixture index (OMI) with a novel GeoDetector-based indicator. This study first integrated application (App) use and mobility patterns from cellphone data to portray residents' occupations and evaluate the OMI in Guangzhou. Then, the mechanism of OMI distribution was analyzed with the GeoDetector model. Next, an optimized GeoDetector-based index, interactive effect variation ratio (IEVR) was proposed to quantify the variation between individual and interactive effects of factors. The results showed that land use mixture was the dominating factor, and that land use mixture, building density, floor area ratio, road density affected the OMI distribution directly. Some interesting findings were uncovered by IEVR. The influences of cultural inclusiveness and metro accessibility were less important in factor detector result, while they were found to be the most influential in an indirect way interacting with other built environment factors. The results suggested that both \\\"hardware facilities \\\" (land use mixture, accessibility) and \\\"soft facilities \\\" (cultural inclusiveness) should be considered in planning a harmonious urban employment space and sustainable city.\",\n \"Title: Uncertainty-aware network alignment\\nYear: 2021\\n\\nAbstract: Network alignment (NA) aims to link common nodes across multiple networks and is an essential task in many graph mining applications. Despite the progress achieved by many recent works, several fundamental limitations have eluded the proper cohesive way of addressing, including matching confusion, lack of the formal treatment of uncertainty, and Point-to-Point (P2P) constraint. This study proposes a novel framework UANA (Uncertainty-Aware Network Alignment) to tackle the limitations of the existing works. By embedding nodes as Gaussian distributions rather than point vectors, UANA enables to capture the uncertainty of a node representation, while being able to discriminate the anchor nodes from the potentially confusing neighbors. We address the P2P matching constraint by introducing an adversarial learning paradigm, which relaxes the exact matching assumption during training with an across-domain generative procedure to reduce the matching errors on testing nodes. In the end, interpretability methods are included to explain the aligning results made by our UANA based on the robust statistics, which enables the explanation of the effect of individual training sample on the NA performance without the need of retraining the model. Extensive experiments conducted on real-world data sets demonstrate that UANA significantly outperforms existing state-of-the-art baselines while providing explainable results.\",\n \"Title: Popularity-Guided Cost Optimization for Live Streaming in Mobile Edge Computing\\nYear: 2022\\n\\nAbstract: Live streaming service usually delivers the content in mobile edge computing (MEC) to reduce the network latency and save the backhaul capacity. Considering the limited resources, it is necessary that MEC servers collaborate with each other and form an overlay to realize more efficient delivery. The critical challenge is how to optimize the topology among the servers and allocate the link capacity so that the cost will be lower with delay constraints. Previous approaches rarely consider server collaborations for live streaming service, and the scheduling delay is usually ignored in MEC, leading to suboptimal performances. In this paper, we propose a popularity-guided overlay model which takes the scheduling delay into consideration and utilizes MEC collaboration to achieve efficient live streaming service. The links and servers are shared among all channel streams and each stream is pushed from cloud servers to MEC servers via the trees. Considering the optimization problem is NP-hard, we propose an effective optimization framework called cost optimization for live streaming (COLS) to predict the channel popularity by a LSTM model with multiscale input data. Finally, we compute topology graph by greedy scheme and allocate the capacity with convex programming. Experimental results show that the proposed approach achieves higher prediction accuracy, reducing the capacity cost by more than 40% with an acceptable delay compared with state-of-the-art schemes.\",\n \"Title: Table Pre-training: A Survey on Model Architectures, Pre-training Objectives, and Downstream Tasks.\\nYear: 2022\\n\\nAbstract: Since a vast number of tables can be easily collected from web pages, spreadsheets, PDFs, and various other document types, a flurry of table pretraining frameworks have been proposed following the success of text and images, and they have achieved new state-of-the-arts on various tasks such as table question answering, table type recognition, column relation classification, table search, formula prediction, etc. To fully use the supervision signals in unlabeled tables, a variety of pretraining objectives have been designed and evaluated, for example, denoising cell values, predicting numerical relationships, and implicitly executing SQLs. And to best leverage the characteristics of (semi-)structured tables, various tabular language models, particularly with specially-designed attention mechanisms, have been explored. Since tables usually appear and interact with free-form text, table pretraining usually takes the form of table-text joint pretraining, which attracts significant research interests from multiple domains. This survey aims to provide a comprehensive review of different model designs, pretraining objectives, and downstream tasks for table pretraining, and we share our thoughts and vision on existing challenges and future opportunities.\",\n \"Title: Multi-scale graph capsule with influence attention for information cascades prediction\\nYear: 2022\\n\\nAbstract: Information cascade size prediction is one of the primary challenges for understanding the diffusion of information. Traditional feature-based methods heavily rely on the quality of handcrafted features, requiring extensive domain knowledge and hard to generalize to new domains. Recently, inspired by the success of deep learning in computer vision and natural language processing, researchers have developed neural network-based approaches for tackling this problem. However, existing deep learning-based methods either focused on modeling the temporal characteristics of cascades but ignored the structural information or failed to take the order-scale and position-scale into consideration in modeling structures of information propagation. This paper proposed a novel graph neural network-based model, called MUCas, to learn the latent representations of cascade graphs from a multi-scale perspective, which can make full use of the direction-scale, high-order-scale, position-scale, and dynamic-scale of cascades via a newly designed MUlti-scale Graph Capsule Network (MUG-Caps) and the influence-attention mechanism. Extensive experiments conducted on two real-world data sets demonstrate that our MUCas significantly outperforms the state-of-the-art approaches.\",\n \"Title: Detecting Abnormal Nodes in Cluster-tree Networks via the Likelihood Ratio Test of Packet Losses\\nYear: 2021\\n\\nAbstract: While packet loss rate is a crucial indicator of network reliability, abnormal nodes dropping the transit traffic lead to higher packet loss rates. One significant challenge is to efficiently distinguish the abnormal nodes from those with normal packet losses. To address this issue, this paper presents a new detection scheme based on the Likelihood Ratio Test (LRT) for cluster-tree networks - a typical architecture of wireless networks. Due to the hierarchical structure of the networks, LRT is implemented in two phases, i.e., the local detection phase at the non-root nodes and the overall detection phase at the root node. The observed forwarding behaviors of the monitored node are modeled and quantified as log-likelihood ratios where the packet loss rate in the alternative hypothesis is a default value. In this way, the log-likelihood ratios are compared with a threshold under the maximum a posteriori probability criterion to identify the anomalies. The correctness of the proposed scheme is theoretically proved if the packet loss rate in the abnormal node exceeds a critical detection point - whose expression is also formally derived. Simulation results validate the critical detection point and demonstrate the superiority of the proposed detection scheme compared to the state-of-the-art methods.\",\n \"Title: Kernel-Based Structural-Temporal Cascade Learning for Popularity Prediction\\nYear: 2021\\n\\nAbstract: One of the main objectives of information cascade popularity prediction is to forecast the future size of a cascade given the observed propagation information. It is an enabling step for many practical applications (e.g., advertisement, academic writing, etc.). Recent advances in neural networks have spurred a few deep learning-based cascade models, which preserve the structural features of information cascades with node embedding and graph neural networks. However, efforts in cascade graph learning as well as its internal temporal dependency, existing methods mainly focus on node-level similarity learning, ignoring the structural equivalence among different sub-graphs that are more informative for information diffusion prediction. Towards this, we present a kernel-based structural-temporal cascade learning model, called CasKernel, to explicitly estimate and encode the structural similarity of cascades with the graph kernels. Moreover, we employ a non sequential process to address the temporal dependency, which can be used to facilitate information popularity prediction. Experiments conducted on both tweets propagation network and academic citation network demonstrate the effectiveness of our method.\",\n \"Title: HGENA: A Hyperbolic Graph Embedding Approach for Network Alignment\\nYear: 2021\\n\\nAbstract: Cross-network alignment aims at identifying users who participate in different social networks, which benefits a variety of downstream social applications such as precise content delivery, fraud detection, and content/user recommender systems. Recent advances in network representations and graph neural networks have spurred various network structure-based methods for capturing underlying node similarities across social networks, thereby addressing the network alignment problem. However, most of the existing solutions rely on embedding methods that compute node similarity in Euclidean space, resulting in severe distortion or semantic loss when representing real-world social networks, which are usually scale free and with hierarchical structures. We address these issues by presenting a novel model: Hyperbolic Graph Embedding for Network Alignment (HGENA), which learns the structural semantics more efficiently by embedding nodes in hyperbolic space instead of Euclidean. HGENA overcomes the scalability issue since it requires far fewer dimensions in Riemannian manifolds and increases the capability of learning hierarchical structures, while enabling smaller distortion for tree-liked networks to facilitate node alignment. We also introduce alternative network mapping functions to compute node similarity across-network based on its distance on the Poincare ball. Experimental evaluations conducted on real world datasets demonstrate that HGENA achieves superior performance on social network alignment, especially for more tree-liked networks.\",\n \"Title: Multi-Objective Distributional Reinforcement Learning for Large-Scale Order Dispatching\\nYear: 2021\\n\\nAbstract: The aim of this paper is to develop a multi-objective distributional reinforcement learning framework for improving order dispatching on large-scale ride-hailing platforms. Compared with traditional RL-based approaches that focus on drivers' income, the proposed framework also accounts for the spatiotemporal difference between the supply and demand networks. Specifically, we model the dispatching problem as a two-objective Semi-Markov Decision Process (SMDP) and estimate the relative importance of the two objectives under some unknown existing policy via Inverse Reinforcement Learning (IRL). Then, we combine Implicit Quantile Networks (IQN) with the traditional Deep Q-Networks (DQN) to jointly learn the two return distributions and adjusting their weights to refine the old policy through on-line planning and achieve a higher supply-demand coherence of the platform. We conduct large-scale dispatching experiments to demonstrate the remarkable improvement of proposed approach on the platform's efficiency.\",\n \"Title: Dynamic Manifold Learning for Land Deformation Forecasting.\\nYear: 2022\\n\\nAbstract: Landslides refer to occurrences of massive ground movements due to geological (and meteorological) factors, and can have disastrous impact on property, economy, and even lead to loss of life. The advances of remote sensing provide accurate and continuous terrain monitoring, enabling the study and analysis of land deformation which, in turn, can be used for possible landslides forecast. Prior studies either rely on independent observations for displacement prediction or model static land characteristics without considering the subtle interactions between different locations and the dynamic changes of the surface conditions. We present DyLand -- Dynamic Manifold Learning with Normalizing Flows for Land deformation prediction -- a novel framework for learning dynamic structures of terrain surface and improving the performance of land deformation prediction. DyLand models the spatial connections of InSAR measurements and estimates conditional distributions of deformations on the terrain manifold with a novel normalizing flow-based method. Instead of modeling the stable terrains, it incorporates surface permutations and captures the innate dynamics of the land surface while allowing for tractable likelihood estimates on the manifold. Our extensive evaluations on curated InSAR datasets from continuous monitoring of slopes prone to landslides show that DyLand outperforms existing bechmarking models.\",\n \"Title: PrEF: Probabilistic Electricity Forecasting via Copula-Augmented State Space Model.\\nYear: 2022\\n\\nAbstract: Electricity forecasting has important implications for the key decisions in modern electricity systems, ranging from power generation, transmission, distribution and so on. In the literature, traditional statistic approaches, machine-learning methods and deep learning (e.g., recurrent neural network) based models are utilized to model the trends and patterns in electricity time-series data. However, they are restricted either by their deterministic forms or by independence in probabilistic assumptions -- thereby neglecting the uncertainty or significant correlations between distributions of electricity data. Ignoring these, in turn, may yield error accumulation, especially when relying on historical data and aiming at multi-step prediction. To overcome these, we propose a novel method named Probabilistic Electricity Forecasting (PrEF) by proposing a non-linear neural state space model (SSM) and incorporating copula-augmented mechanism into that, which can learn uncertainty-dependencies knowledge and understand interactive relationships between various factors from large-scale electricity time-series data. Our method distinguishes itself from existing models by its traceable inference procedure and its capability of providing high-quality probabilistic distribution predictions. Extensive experiments on two real-world electricity datasets demonstrate that our method consistently outperforms the alternatives.\",\n \"Title: A Probabilistic Framework for Land Deformation Prediction (Student Abstract).\\nYear: 2022\\n\\nAbstract: The development of InSAR (satellite Interferometric Synthetic Aperture Radar) enables accurate monitoring of land surface deformations, and has led to advances of deformation forecast for preventing landslide, which is one of the severe geological disasters. Despite the unparalleled success, existing spatio-temporal models typically make predictions on static adjacency relationships, simplifying the conditional dependencies and neglecting the distributions of variables. To overcome those limitations, we propose a Distribution Aware Probabilistic Framework (DAPF), which learns manifold embeddings while maintaining the distribution of deformations. We obtain a dynamic adjacency matrix upon which we approximate the true posterior while emphasizing the spatio-temporal characteristics. Experimental results on real-world dataset validate the superior performance of our method.\",\n \"Title: Learning Contrastive Multi-View Graphs for Recommendation (Student Abstract).\\nYear: 2022\\n\\nAbstract: This paper exploits self-supervised learning (SSL) to learn more accurate and robust representations from the user-item interaction graph. Particularly, we propose a novel SSL model that effectively leverages contrastive multi-view learning and pseudo-siamese network to construct a pre-training and post-training framework. Moreover, we present three graph augmentation techniques during the pre-training stage and explore the effects of combining different augmentations, which allow us to learn general and robust representations for the GNN-based recommendation. Simple experimental evaluations on real-world datasets show that the proposed solution significantly improves the recommendation accuracy, especially for sparse data, and is also noise resistant.\",\n \"Title: Linking Transformer to Hawkes Process for Information Cascade Prediction (Student Abstract).\\nYear: 2022\\n\\nAbstract: Information cascade is typically formalized as a process of (simplified) discrete sequence of events, and recent approaches have tackled its prediction via variants of recurrent neural networks. However, the information diffusion process is essentially an evolving directed acyclic graph (DAG) in the continuous-time domain. In this paper, we propose a transformer enhanced Hawkes process (Hawkesformer), which links the hierarchical attention mechanism with Hawkes process to model the arrival stream of discrete events continuously. A two-level attention architecture is used to parameterize the intensity function of Hawkesformer, which captures the long-term dependencies between nodes in graph and better embeds the cascade evolution rate for modeling short-term outbreaks. Experimental results demonstrate the significant improvements of Hawkesformer over the state-of-the-art.\",\n \"Title: Large-Scale IP Usage Identification via Deep Ensemble Learning (Student Abstract).\\nYear: 2022\\n\\nAbstract: Understanding users' behavior via IP addresses is essential towards numerous practical IP-based applications such as online content delivery, fraud prevention, and many others. Among which profiling IP address has been extensively studied, such as IP geolocation and anomaly detection. However, less is known about the scenario of an IP address, e.g., dedicated enterprise network or home broadband. In this work, we initiate the first attempt to address a large-scale IP scenario prediction problem. Specifically, we collect IP scenario data from four regions and propose a novel deep ensemble learning-based model to learn IP assignment rules and complex feature interactions. Extensive experiments support that our method can make accurate IP scenario identification and generalize from data in one region to another.\",\n \"Title: Conditional Collaborative Filtering Process for Top-K Recommender System (Student Abstract).\\nYear: 2022\\n\\nAbstract: Conditional neural process (CNP) has been extensively applied into data analyzing tasks due to its excellent ability to make accurate predictions for incomplete data points. However, in literature there are only few works that studied the CNPin recommendation systems. In this work, we propose CCFP, which is a collaborative filtering method that differs from other CF models by incorporating CNP into encoder-decoder architecture. By analyzing the complete user-item interaction data, our model fits a global representation that can better rep-resenting the features of users and items. CCFP can significantly improve the recommendation performance compared to baselines by predicting items for the target users with their incomplete observation data.\",\n \"Title: Fine-Grained Urban Flow Inference via Normalizing Flow (Student Abstract).\\nYear: 2022\\n\\nAbstract: Fine-grained urban flow inference (FUFI) aims to infer the coarse-grained (CG) urban flow map to the corresponding fine-grained (FG) one, which plays an important role in efficient traffic monitoring and management in smart cities. In FUFI, the CG map can be obtained with only a small number of monitoring devices, greatly reducing the overhead of deploying devices and the costs of maintenance, labor, and electricity. Existing FUFI methods are mainly based on techniques from image super-resolution (SR) models, which cannot fully consider the influence of external factors and face the ill-posed problem in SR tasks. In this paper, we propose UFI-Flow, a novel approach for addressing the FUFI problem by learning the conditional distributions of CG and FG map pairs. Given the CG map and the latent variables, the corresponding FG map is inferred by invertible transformations. In addition, an augmented distribution fusion mechanism is further proposed to constrain the urban flow distribution within the influence of external factors. We provide a new large-scale real-world FUFI dataset and show that UFI-Flow significantly outperforms the strong baselines.\",\n \"Title: Heterogeneous dynamical academic network for learning scientific impact propagation\\nYear: 2022\\n\\nAbstract: Quantifying and predicting the long-term impact of both scientific papers and individual authors have important implications for many academic policy decisions, from identifying emerging trends to assessing the merits of proposals for potential funding. This paper presents SI-HDGNN, a novel heterogeneous dynamical graph neural network that explicitly models a heterogeneous, weighted, directed and attributed academic graph, enabling a prediction of the cumulative scientific impact of papers and authors by a specifically designed aggregation method. Unlike the existing feature-based or homogeneous approaches, SI-HDGNN addresses the problem by capturing the temporal–structural characteristics of the papers and authors as well as their complex interactions and long-term dependencies. Extensive experiments conducted on three large-scale multidisciplinary academic datasets demonstrate its superior performance in predicting the long-term scientific impact of both scientific papers and authors.\",\n \"Title: Identifying user geolocation with Hierarchical Graph Neural Networks and explainable fusion\\nYear: 2022\\n\\nAbstract: Determining user geolocation from social media data is essential in various location-based applications — from improved transportation/supply management, through providing personalized services and targeted marketing, to better overall user experiences. Previous methods rely on the similarity of user posting content and neighboring nodes for user geolocation, which suffer the problems of: (1) position-agnostic of network representation learning, which impedes the performance of their prediction accuracy; and (2) noisy and unstable user relation fusion due to the flat graph embedding methods employed. This work presents Hierarchical Graph Neural Networks (HGNN) – a novel methodology for location-aware collaborative user-aspect data fusion and location prediction. It incorporates geographical location information of users and clustering effect of regions and can capture topological relations while preserving their relative positions. By encoding the structure and features of regions with hierarchical graph learning, HGNN can primarily alleviate the problem of noisy and unstable signal fusion. We further design a relation mechanism to bridge connections between individual users and clusters, which not only leverages the information of isolated nodes that are useless in previous methods but also captures the relations between unlabeled nodes and labeled subgraphs. Furthermore, we introduce a robust statistics method to interpret the behavior of our model by identifying the importance of data samples when predicting the locations of the users. It provides meaningful explanations on the model behaviors and outputs, overcoming the drawbacks of previous approaches that treat user geolocation as “black-box” modeling and lacking interpretability. Comprehensive evaluations on real-world Twitter datasets verify the proposed model’s superior performance and its ability to interpret the user geolocation results.\",\n \"Title: Multi-view learning with distinguishable feature fusion for rumor detection\\nYear: 2022\\n\\nAbstract: Researchers, enterprises, and governments have made great efforts to detect misinformation promptly and accurately. Traditional solutions either examine complicated hand-crafted features or rely heavily on the constructed credibility networks to extract useful indicators for discerning false information. However, such approaches require insightful domain expert knowledge and intensive feature engineering that are often non-generalizable. Recent advances in deep learning techniques have spurred learning high-level representations from textual and image content and discovering diffusion patterns with various neural networks. Despite the progress made by these methods, they still face the problem of overdependence on the content features and fail to discriminate against the influence of each user involved in the process of rumor spreading. Different user-aspect information plays different roles in various stages of rumor diffusion, effectively extract features from each aspect, and aggregate the learned features into a unique representation, which has not been well investigated. To address these limitations, we propose a novel model, UMLARD (User-aspect Multi-view Learning with Attention for Rumor Detection), to effectively learn the representation of different views of the users who engaged in spreading the tweet, and fuse the learned features through the distinguishable fusion mechanism. Finally, we concatenate the learned user-aspect features with content features to form a unique representation and feed it into a fully connected layer to predict the label of rumors. Our experiments conducted on real-world datasets demonstrate that UMLARD significantly improves the rumor detection performance compared to state-of-the-art baselines. It also allows explainability of the model behavior and the predicted results.\",\n \"Title: Social-trust-aware variational recommendation\\nYear: 2022\\n\\nAbstract: Most existing studies that employ social-trust information to solve the data sparsity issue in recommender systems assume that socially connected users have equal influence on each other. However, this assumption does not hold in practice since users and their friends may not have similar interests because social connections are multifaceted and exhibit heterogeneous strengths in different scenarios. Therefore, estimating the diverse levels of influence among entities (users/items/social connections) is very important in advancing social recommender systems. Towards this goal, we propose a new model named Social-Trust-Aware Variational Recommendation (SOAP-VAE). Particularly, SOAP-VAE leverages graph attention network techniques to capture the varying levels of influence and the complex interaction patterns among all the entities collectively and holistically. In doing so, heterogeneity among entities is obtained seamlessly. Consequently, we generate social-trust-aware item embedding representations in which the right level of influence has been integrated. Next, based on these rich social-trust-aware item representations, we formulate the first-ever social-trust-aware prior in literature. Unlike priors utilized in earlier VAE-based recommendation models, this novel prior aids in dealing with the issue of posterior-collapse and can effectively capture the uncertainty of latent space. In effect, the model produces better latent representations, which significantly alleviates the data sparsity issue. Finally, we empirically show that SOAP-VAE outperforms several state-of-the-art baselines on three real-world data sets.\",\n \"Title: SNPD: Semi-Supervised Neural Process Dehazing Network with Asymmetry Pseudo Labels\\nYear: 2022\\n\\nAbstract: Haze can cause a significant reduction in the contrast and brightness of images. CNN-based methods have achieved benign performance on synthetic data. However, they show weak generalization performance on real data because they are only trained on fully labeled data, ignoring the role of natural data in the network. That is, there exists distribution shift. In addition to using little real data for training image dehazing networks in the literature, few studies have designed losses to constrain the intermediate latent space and the output simultaneously. This paper presents a semi-supervised neural process dehazing network with asymmetry pseudo labels. First, we use labeled data to train a backbone network and save intermediate latent features and parameters. Then, in the latent space, the neural process maps the latent features of real data to the latent space of synthetic data to generate one pseudo label. One neural process loss is proposed here. For situations where the image may be darker after dehazing, another pseudo label is created, and one new loss is used to guide the dehazing result at the output end. We combine the two pseudo labels with designed losses to suppress the distribution shift and guide better dehazing results. Finally, the artificial and hazy natural images are tested experimentally to demonstrate the method's effectiveness.\",\n \"Title: Landslide Displacement Prediction via Attentive Graph Neural Network\\nYear: 2022\\n\\nAbstract: Landslides are among the most common geological hazards that result in considerable human and economic losses globally. Researchers have put great efforts into addressing the landslide prediction problem for decades. Previous methods either focus on analyzing the landslide inventory maps obtained from aerial photography and satellite images or propose machine learning models-trained on historical land deformation data-to predict future displacement and sedimentation. However, existing approaches generally fail to capture complex spatial deformations and their inter-dependencies in different areas. This work presents a novel landslide prediction model based on graph neural networks, which utilizes graph convolutions to aggregate spatial correlations among different monitored locations. Besides, we introduce a novel locally historical transformer network to capture dynamic spatio-temporal relations and predict the surface deformation. We conduct extensive experiments on real-world data and demonstrate that our model significantly outperforms state-of-the-art approaches in terms of prediction accuracy and model interpretations.\",\n \"Title: Multi-receptive Field Aggregation Network for single image deraining\\nYear: 2022\\n\\nAbstract: Image deraining is a significant problem that ensures the visual quality of images to prompt computer vision systems. However, due to the insufficiency of captured rain streaks features and global information, current image deraining methods often face the issues of rain streaks remaining and image blurring. In this paper, we propose a Multi-receptive Field Aggregation Network (MRFAN) to restore a cleaner rain-free image. Specifically, we construct a Multi-receptive Field Feature Extraction Block (MFEB) to capture rain features with different receptive fields. In MFEB, we design a Self-supervised Block (SSB) and an Aggregation Block (AGB). SSB can make the network adaptively focus on the critical rain features and rain-covered areas. AGB effectively aggregates and redistributes the multi-scale features to help the network simulate rain streaks better. Experiments show that our method achieves better results on both synthetic datasets and real-world rainy images.\",\n \"Title: Test-Driven Feature Extraction of Web Components\\nYear: 2022\\n\\nAbstract: With the growing requirements of web applications, web components are developed to package the implementation of commonly-used features for reuse. In some cases, the developer may want to reuse some features which cannot be customized by the component's APIs. He/she has to extract the implementation by hand. It is labor-intensive and error-prone. Considering the widely-used test cases which can be useful to specify the software features, a test-driven approach is proposed to extract the implementation of the desired features in web components. The satisfaction of the user's requirements is transformed into the passing rate of user-specified test cases. In this way, the quality of the extraction result can be evaluated automatically. Meanwhile, a record/replay-based GUI test generation method is proposed to ensure that the extraction result has the correct GUI appearance. To extract the feature implementation, a hierarchical genetic algorithm is proposed to find the code snippet that can pass all the tests and has the approximate smallest size. We compare our method with two existing feature extraction methods. The result shows that our method can extract the correct implementation with the minimum size. A human-subject study is conducted to show the effectiveness and weaknesses of our method in helping users extract the features.\",\n \"Title: Variational cold-start resistant recommendation\\nYear: 2022\\n\\nAbstract: Conventionally, cold-start limitations are managed by leveraging side information such as social-trust relationships. However, the relationships between users in social networks are complex, uncertain, and sparse. Therefore, it is necessary to extract beneficial social connections to make the recommendation models cold-start resistant. Towards this end, we propose a novel recommendation model called Variational Cold-start Resistant Recommendation (CORE-VAE). More concretely, we employ a social-aware similarity function and a graph convolutional network (GCN) to generate robust social-aware user representations that account for the complexities, uncertainties, and sparse nature of the social-trust network. Subsequently, these powerful social-aware representations aid us in producing cold-start resistant rating vectors for all users. To explore the rich user rating information, we propose an expressive variational autoencoder (VAE) model. Unlike earlier VAE-based CF models, CORE-VAE utilizes a novel prior distribution and a well-designed skip-generative network to alleviate the posterior collapse issue considerably. Besides, CORE-VAE can also capture the latent space’s uncertainty and ensure that observations and their accompanying latent variables have high mutual information. Overall, these novel techniques dramatically help produce better latent representations for generating more accurate recommendations. We show that CORE-VAE outperforms numerous competitive baseline models on real-world datasets through comprehensive empirical evaluation and analysis.\",\n \"Title: Quantification and Analysis of Layer-wise and Pixel-wise Information Discarding.\\nYear: 2022\\n\\nAbstract: This paper presents a method to explain how the information of each input variable is gradually discarded during the forward propagation in a deep neural network (DNN), which provides new perspectives to explain DNNs. We define two types of entropy-based metrics, i.e. (1) the discarding of pixel-wise information used in the forward propagation, and (2) the uncertainty of the input reconstruction, to measure input information contained by a specific layer from two perspectives. Unlike previous attribution metrics, the proposed metrics ensure the fairness of comparisons between different layers of different DNNs. We can use these metrics to analyze the efficiency of information processing in DNNs, which exhibits strong connections to the performance of DNNs. We analyze information discarding in a pixel-wise manner, which is different from the information bottleneck theory measuring feature information w.r.t. the sample distribution. Experiments have shown the effectiveness of our metrics in analyzing classic DNNs and explaining existing deep-learning techniques. The code is available at https://github.com/haotianSustc/deepinfo.\",\n \"Title: Combination Complex-Valued Bayesian Compressive Sensing Method for Sparsity Constrained Deconvolution Beamforming\\nYear: 2022\\n\\nAbstract: Several deconvolution methods have been proposed to reduce the mainlobe width and sidelobe intensity of conventional beamforming results without increasing the array aperture; however, most of them cannot perform well in the face of coherent targets. Therefore, it is discerning to deconvolve the complex-valued beamforming result rather than the beamforming intensity. However, conventional deconvolution methods focus on the beam intensity, and only a few studies have investigated complex-valued deconvolution beamforming (CDB). Considering the sparse property of the targets in practice, the CDB can be converted to a complex-valued inverse compressive sensing problem and put into the Bayesian framework. To solve it efficiently, a complex-valued relevance-vector-machine (RVM) tool is used to build the complex-valued Bayesian compressive sensing (C-BCS) method that has excellent performance in terms of recovery accuracy and operating speed. However, the C-BCS method is not stable for the CDB because the point spread function is a rank deficiency matrix. To overcome this problem, we propose the combination C-BCS method that combines the block-sparse and C-BCS methods to improve the performance of solving the CDB. The simulation results proved that the proposed method performed better than intensity-based deconvolution methods for the beamforming results generated by the coherent targets. A beamforming image of a pool scene captured by a narrowband forward-looking sonar system was adopted to test various deconvolution methods, and the proposed method exhibited superiority in sidelobe suppression.\",\n \"Title: Generating Personas for Products on Social Media: A Mixed Method to Analyze Online Users\\nYear: 2022\\n\\nAbstract: The purpose of this research is to develop a methodology that combines the quantitative and the qualitative analysis to generate personas for products on social platforms. The user data on social platforms contain massive information relating to the lifestyle people have and the products people use or are interested. By analyzing the specific content generated by users on social platforms, e.g., content involving the term \\\"tablet,\\\" it is possible to reveal how the users consider or use the product, \\\"tablet.\\\" By analyzing the users' homepages, the information relating to the users' daily life can be found. We collected 276, 675 pieces of relevant data regarding the product, \\\"tablet,\\\" from 12, 965 online users on China's widely used social media platforms. Then automatic user segments and the profiles of each group were generated and structured by natural language processing technology. The results of these quantitative analyses were then qualitatively examined by manual analyses, which provide additional insights and detailed descriptions on the automatically generated persona profiles. In this study, six personas representing distinct user types were created. The mixed method of combining the quantitative and qualitative methods makes the generation of personas faster and more insightful. The generated personas can represent real user behavior and characteristics and can provide insights into the products, which also can provide support on designing new products and optimizing existing products.\",\n \"Title: Contextual spatio-temporal graph representation learning for reinforced human mobility mining\\nYear: 2022\\n\\nAbstract: The rapid development of location-based services spurred a large number of user-centric applications. Particularly, an interesting topic has attracted the attention of researchers that is to link trajectories to users (TUL). Despite the significant progress made by recent deep learning-based human mobility learning models, tackling TUL problem is still challenging. In this paper, we propose a novel reinforced trajectory learning approach called GraphTUL that implements an adversarial network with the policy gradient to improve the identification ability and leverages both labeled and unlabeled trajectories to address the insufficient label issue in a semi-supervised manner. Besides, some critical factors related to personal context and indispensable elements in current mobility learning models are still missing. Thus, we propose a novel graph-based human motion representation model (CGE) to exploit the contextual information from users’ trajectories for alleviating data sparsity and contextual constraint issues. CGE builds a unified graph with historical check-ins to reflect users’ geographical preferences and visiting intentions. It allows us to sample synthetic but realistic trajectories for augmenting data and enhancing contextual check-in embedding. We also successfully apply it to next check-in prediction task. The experimental results conducted on several real-world datasets demonstrate that our proposed method achieves significantly better performance than the state-of-the-art baselines.\",\n \"Title: Temporally Multi-Modal Semantic Reasoning with Spatial Language Constraints for Video Question Answering\\nYear: 2022\\n\\nAbstract: Video question answering (QA) aims to understand the video scene and underlying plot by answering video questions. An algorithm that can competently cope with this task needs to be able to: (1) collect multi-modal information scattered in the video frame sequence while extracting, interpreting, and utilizing the potential semantic clues provided by each piece of modal information in the video, (2) integrate the multi-modal context of the above semantic clues and understand the cause and effect of the story as it evolves, and (3) identify and integrate those temporally adjacent or non-adjacent effective semantic clues implied in the above context information to provide reasonable and sufficient visual semantic information for the final question reasoning. In response to the above requirements, a novel temporally multi-modal semantic reasoning with spatial language constraints video QA solution is reported in this paper, which includes a significant feature extraction module used to extract multi-modal features according to a significant sampling strategy, a spatial language constraints module used to recognize and reason spatial dimensions in video frames under the guidance of questions, and a temporal language interaction module used to locate the temporal dimension semantic clues of the appearance features and motion features sequence. Specifically, for a question, the result processed by the spatial language constraints module is to obtain visual clues related to the question from a single image and filter out unwanted spatial information. Further, the temporal language interaction module symmetrically integrates visual clues of the appearance information and motion information scattered throughout the temporal dimensions, obtains the temporally adjacent or non-adjacent effective semantic clue, and filters out irrelevant or detrimental context information. The proposed video QA solution is validated on several video QA benchmarks. Comprehensive ablation experiments have confirmed that modeling the significant video information can improve QA ability. The spatial language constraints module and temporal language interaction module can better collect and summarize visual semantic clues.\",\n \"Title: A seizure detection method based on hypergraph features and machine learning\\nYear: 2022\\n\\nAbstract: Effective feature extraction is the key to successful seizure detection. A good feature should be adaptable, noise resistant, and informative. In this study, a seizure detection method based on hypergraph features and machine learning was proposed. During the preprocessing step, the magnitude-squared coherence (MSC) method was used to select the useful channels and frequency band. The hypergraph method was introduced to represent the correlation network based on the MSC result. Hypergraphs can show relationships between channels, and they have higher dimensional properties than normal graphs. To quantify the characteristics of these channels, three feature coefficients, which are HG-Independent(HG-Ind), HG-Dependent(HG-Dep), and HG-Share(HG-Sha), were derived and input as features into the machine learning algorithm. Two machine learning algorithms, random forest (RF) and support vector machine (SVM), were tested on the data of eight patients in our study. According to the results, RF had a better performance than SVM, and the group of three features performed better than the single feature. Three additional methods from other papers, extra-trees, random forest based on spectral correlation, and neural networks, were compared with the HG-RF, and the HG-RF had the best performance, with an accuracy of 96.30%. This method showed resistance to noise and adaptability for different patient data. In addition, this method facilitated a balance between effectiveness and efficiency and provided a new idea for online detection of epilepsy.\",\n \"Title: Double-Check Soft Teacher for Semi-Supervised Object Detection.\\nYear: 2022\\n\\nAbstract: In the semi-supervised object detection task, due to the scarcity of labeled data and the diversity and complexity of objects to be detected, the quality of pseudo-labels generated by existing methods for unlabeled data is relatively low, which severely restricts the performance of semi-supervised object detection. In this paper, we revisit the pseudo-labeling based Teacher-Student mutual learning framework for semi-supervised object detection and identify that the inconsistency of the location and feature of the candidate object proposals between the Teacher and the Student branches are the fatal cause of the low quality of the pseudo labels. To address this issue, we propose a simple yet effective technique within the mainstream teacher-student framework, called Double Check Soft Teacher, to overcome the harm caused by insufficient quality of pseudo labels. Specifically, our proposed method leverages teacher model to generate pseudo labels for the student model. Especially, the candidate boxes generated by the student model based on the pseudo label will be sent to the teacher model for \\\"double check\\\", and then the teacher model will output probabilistic soft label with background class for those candidate boxes, which will be used to train the student model. Together with a pseudo labeling mechanism based on the sum of the TOP-K prediction score, which improves the recall rate of pseudo labels, Double Check Soft Teacher consistently surpasses state-of-the-art methods by significant margins on the MS-COCO benchmark, pushing the new state-of-the-art. Source codes are available at https://github.com/wkfdb/DCST.\",\n \"Title: Identifying IP Usage Scenarios: Problems, Data, and Benchmarks\\nYear: 2022\\n\\nAbstract: Given an IP address, understanding its initial assignment,and predicting its potential usage can significantly help toward improving efficiency of many practical IP-based applications, such as Ad-recommendation, point of interest selection, fraud detection, and Internet service optimization. However, there are only a few prior studies conducted on predicting IP usage from its assignment. Surprisingly, there does not exist a benchmark dataset available to academia that can be used to investigate and develop IP usage predictions for different IP applications. In this work, we formulate the IP usage prediction problem; specifically, we collect large-scale, real-world data and extract salient features using sophisticated networking tools such as different network signals, trace route delay, IP block usage, and geographical landmarks. We showcase a series of tabular information retrieval methods to learn network signals and their interactions, and identify the IP usage scenarios. We believe our datasets and algorithms can benefit the community to facilitate relevant research in this domain, yielding more efficient and effective solutions to multiple categories of applications.\",\n \"Title: MDP2 Forest: A Constrained Continuous Multi-dimensional Policy Optimization Approach for Short-video Recommendation\\nYear: 2022\\n\\nAbstract: In the ecology of short video platforms, the optimal exposure proportion of each video category is crucial to guide recommendation systems and content production in a macroscopic way. Though extensive studies on recommendation systems are devoted to providing the most well-matched videos for each view request, fitting the data without considering inherent biases such as selection bias and exposure bias will result in serious issues. In this paper, we formalize the exposure proportion strategy as a policy-making problem with multi-dimensional continuous treatment under certain constraints from a causal inference point of view. We propose a novel ensemble policy learning method based on causal trees, called Maximum Difference of Preference Point Forest (MDP2 Forest), which overcomes the shortcomings of existing policy learning approaches. Experimental results on both simulated and synthetic datasets show the superiority of our algorithm compared to other policy learning or causal inference methods in terms of the treatment estimation accuracy and the mean regret. Furthermore, the proposed MDP2 Forest method can also adapt to a wide range of business settings such as imposing different kinds of constraints on the multi-dimensional treatment.\",\n \"Title: Connecting the Hosts: Street-Level IP Geolocation with Graph Neural Networks\\nYear: 2022\\n\\nAbstract: Pinpointing the geographic location of an IP address is important for a range of location-aware applications spanning from targeted advertising to fraud prevention. The majority of traditional measurement-based and recent learning-based methods either focus on the efficient employment of topology or utilize data mining to find clues of the target IP in publicly available sources. Motivated by the limitations in existing works, we propose a novel framework named GraphGeo, which provides a complete processing methodology for street-level IP geolocation with the application of graph neural networks. It incorporates IP hosts knowledge and kinds of neighborhood relationships into the graph to infer spatial topology for high-quality geolocation prediction. We explicitly consider and alleviate the negative impact of uncertainty caused by network jitter and congestion, which are pervasive in complicated network environments. Extensive evaluations across three large-scale real-world datasets demonstrate that GraphGeo significantly reduces the geolocation errors compared to the state-of-the-art methods. Moreover, the proposed framework has been deployed on the web platform as an online service for 6 months.\",\n \"Title: Mining Spatio-Temporal Relations via Self-Paced Graph Contrastive Learning\\nYear: 2022\\n\\nAbstract: Modeling complex spatial and temporal dependencies are indispensable for location-bound time series learning. Existing methods, typically relying on graph neural networks (GNNs) and temporal learning modules based on recurrent neural networks, have achieved significant performance improvements. However, their representation capabilities and prediction results are limited when pre-defined graphs are unavailable. Unlike spatio-temporal GNNs focusing on designing complex architectures, we propose a novel adaptive graph construction strategy: Self-Paced Graph Contrastive Learning (SPGCL). It learns informative relations by maximizing the distinguishing margin between positive and negative neighbors and generates an optimal graph with a self-paced strategy. Specifically, the existing neighborhoods iteratively absorb more reliable nodes with the highest affinity scores as new neighbors to generate the next-round neighborhoods, and augmentations are applied to improve the transferability and robustness. As the adaptively self-paced graph approaches the optimized graph for prediction, the mutual information between nodes and the corresponding neighbors is maximized. Our work provides a new perspective of addressing spatio-temporal learning problems beyond information aggregation in Euclidean space and can be generalized to different tasks. Extensive experiments conducted on two typical spatio-temporal learning tasks (traffic forecasting and land displacement prediction) demonstrate the superior performance of SPGCL against the state-of-the-art.\",\n \"Title: A New Abnormal Node Detection Method With Dynamic Hoeffding Test\\nYear: 2022\\n\\nAbstract: In this letter, we propose a new method based on the dynamic Hoeffding test that can distinguish the abnormal relay nodes from those with normal packet loss in wireless communications. An asymptotic analysis of the detection performance on the Hoeffding test is conducted to determine the new dynamic detection threshold for decreasing the total probability of errors. With the theoretical guarantees, both false alarm and missed detection probabilities of the proposed scheme converge \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">exponentially</i>\\n as the number of detection periods increases. Simulation results validate our analysis and demonstrate the superior detection performance of the proposed method.\",\n \"Title: Exploring Image Regions Not Well Encoded by an INN\\nYear: 2022\\n\\nAbstract: This paper proposes a method to clarify image regions that are not well encoded by an invertible neural network (INN), i.e. image regions that significantly decrease the likelihood of the input image. The proposed method can diagnose the limitation of the representation capacity of an INN. Given an input image, our method extracts image regions, which are not well encoded, by maximizing the likelihood of the image. We explicitly model the distribution of not-well-encoded regions. A metric is proposed to evaluate the extraction of the not-well-encoded regions. Finally, we use the proposed method to analyze several state-of-the-art INNs trained on various benchmark datasets.\",\n \"Title: HydroFlow: Towards probabilistic electricity demand prediction using variational autoregressive models and normalizing flows\\nYear: 2022\\n\\nAbstract: We present HydroFlow, a novel deep generative model for predicting the electricity generation demand of large-scale hydropower stations. HydroFlow uses a latent stochastic recurrent neural network to capture the dependencies in the multivariate time series. It not only utilizes the hidden state of the neural network, but also considers the uncertainty of variables related to natural and social factors. We also introduce an end-to-end approach based on generative flows to approximate the posterior distribution of time series with exact likelihoods. Our model is powerful as adding stochasticity to different factors (e.g., reservoir capacity and water-flow measurements) and thus overcomes the expressiveness limitations of deterministic prediction methods. It also enables trainable latent transformations that can improve the model interpretability. We evaluate HydroFlow on the data collected from the hydropower stations of a large-scale hydropower development company. Experimental results show that our model significantly outperforms the state-of-the-art baseline methods while providing explainable results.\",\n \"Title: Transformer-enhanced Hawkes process with decoupling training for information cascade prediction\\nYear: 2022\\n\\nAbstract: The ability to model the information diffusion process and predict its size is crucial to understanding information propagation mechanism and is useful for many applications such as popularity prediction and fake news detection. Recent research works have attempted to address the problem of information cascade prediction using two basic paradigms: (1) sequential methods, e.g., recurrent neural networks (RNNs), and (2) graph learning techniques to retain the topological information and enable consideration of structural relationships among diffusion participants. However, existing models consider the topological and temporal features separately, falling short of simulating their entanglement in the diffusion process. As a consequence, since the evolving directed acyclic graph (DAG) of information diffusion is intrinsically coupled with both topological and temporal dependencies, there is a loss of cross-domain information. In this paper, we propose a transformer enhanced Hawkes process (Hawkesformer), which links the hierarchical attention mechanism to Hawkes self-exciting point process for information cascade prediction. Specifically, we extend traditional Hawkes process with a topological horizon and efficiently acquire knowledge from continuous-time domain. A two-level attention architecture is used to parameterize the intensity function of Hawkesformer. At the first-level, we disentangle the primary and non-primary paths to simulate the coupled topological and temporal information for capturing the global dependencies between the nodes in a graph. At the second-level, a local pooling attentive module is proposed to embed the cascade evolution rate for modeling short-term outbreaks. Extensive experiments on two real-world datasets demonstrate the significant performance improvements of Hawkesformer over existing state-of-the-art models.\",\n \"Title: A probabilistic multi-criteria evaluation framework for integrated energy system planning\\nYear: 2022\\n\\nAbstract: For the planning of integrated energy system (IES), it is of great significance to accurately evaluate the performance of the system’s energy supply in a number of aspects including e.g., economy, operational efficiency, environmental effects and security. In order to address the difficulties associated with uncertainties of evaluation indices, one probabilistic multi-criteria evaluation (PMCE) framework is proposed in this study for a class of integrated energy supply systems. In this framework, the evaluation is carried out based on probability distributions instead of deterministic values of evaluation indices, and to determine the criterion weights in PMCE, a Dirichlet mixture model (DMM) is applied to determine the weights required in PMCE to represent the priorities of different criteria. A case study has been carried out to evaluate the overall performce of five energy supply systems with a smart community demonstrative project. The results show that the proposed approach outperforms existing average-based and maximum entropy principle (MEP)-based approaches and demonstrate good robustness when encountering changes in the prices of electricity and natural gas.\",\n \"Title: Unsupervised Domain Adaptation Image Dehazing with Contrastive Nearest-Farthest Subspace Distance\\nYear: 2022\\n\\nAbstract: Haze can cause significant changes in the data domain of the image. Due to domain-shift problem, the model trained on the synthetic haze images has a weak or even invalid dehazing ef-fect on the real data. This paper proposes an unsupervised domain adaptation dehazing method based on the nearest-farthest subspace distance in response to this problem. For the middle convolved features, the matrix singular value de-composition is used to obtain the basis vectors of the support subspace. Narrowing the angle between the basis vectors of natural and synthetic haze domains could reduce the differ-ence between the data domains. In subspace, a newly defined distance with a new penalty term named subspace measure distance is employed to constrain the model. Furthermore, to avoid search blindness of the proposed method in the real data training phase, we propose the nearest-farthest subspace distance inspired by contrastive learning. In addition, we use a new training strategy. Finally, the experimental tests on the synthetic and real images prove the effectiveness of the pro-posed method.\",\n \"Title: Integrating Heterogeneous Sources for Learned Prediction of Vehicular Data Consumption\\nYear: 2022\\n\\nAbstract: In addition to the multiple sensors to measure parameters that can be used to improve both safety and efficiency, modern vehicles also gather information about external data (e.g., traffic conditions, weather) which, if properly used, could further improve the overall trip experience. Specifically, when it comes to navigation, one source that can provide increased context awareness, especially for autonomous driving, are the High Definition (HD) maps, which have recently witnessed a tremendous growth of popularity in vehicular technology and use. As they are limited to a particular geographic area, different portions need to be downloaded (and processed) on multiple occasions throughout a given trip, along with the other data from other internal and external sources. In this paper, we provide an effective deep learning approach for the recently introduced problem of Predicting Map Data Consumption (PMDC) in the future time instants for a given trip. We propose a novel methodology that integrates multiple data sources (road network, traffic, historic trips, HD maps) and, for a given trip, enables prediction of the map data consumption. Our experimental observations demonstrate the benefits of the proposed approach over the candidate baselines.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":146,"string":"146"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13374,"string":"13,374"}}},{"rowIdx":13375,"cells":{"question_id":{"kind":"string","value":"Mahta Moghaddam"},"question":{"kind":"string","value":"Generate an abstract for the title \"Full-Wave Electromagnetic Scattering From Rough Surfaces With Buried Inhomogeneities.\" using the following items: 1. Electromagnetic scattering \n2. Rough surfaces \n3. Buried inhomogeneities \n4. Three dimensions modeling \n5. Simulation of rocks, ice particles, and vegetation roots."},"answer":{"kind":"string","value":"We develop a methodology for modeling coherent electromagnetic scattering from rough surfaces with buried inhomogeneities in three dimensions. The inhomogeneities considered in this paper include random spherical media, random cylindrical media, and root-like cylindrical clusters. They are used to simulate rocks, ice particles, and vegetation roots buried beneath the ground surface that can be see..."},"correct_answer":{"kind":"string","value":"We develop a methodology for modeling coherent electromagnetic scattering from rough surfaces with buried inhomogeneities in three dimensions. The inhomogeneities considered in this paper include random spherical media, random cylindrical media, and root-like cylindrical clusters. They are used to simulate rocks, ice particles, and vegetation roots buried beneath the ground surface that can be see..."},"documents":{"kind":"list like","value":["Title: Sensitivity Analysis of the Simulated Annealing Method to Measurement Noise for the Inversion of Subsurface Parameters of Two Layer Rough Surfaces\nYear: 2008\n\nAbstract: where the quantities σo pq (X; fi ,θ j) and dpq (fi ,θ j) are, respectively, the calculated and measured backscattering coefficient of the layered structure at a certain frequency and observation angle for pq polarization. The backscattering coefficients σo vv and σo hh are available from our incoherent first order SPM forward model (3), which is also used to synthesize the measured data to develop and validate the inversion algorithm. The values of Nf and Nθ are, respectively, the number of frequency points and measurement angles used in the measurement. We use nine model parameters to characterize the two layer structure. These parameters are real parts of the layers permittivities (� 1r and � 2r), conductivities of the layers (σ1 and σ2), the standard deviation and correlation length of each interface (σfi and lfi), along with the mean separation between the two rough interfaces (d). The vector of unknowns, X, is defined such that X(1) = � 1r, X(2) = σ1, X(3) = � 2r, X(4) = σ2, X(5) = d, X(6) = lf1 , X(7) = σf1, X(8) = lf2, and X(9) = σf2 . We have shown that error in the a-priori values assigned to known model parameters would result in large errors in the solution. Therefore, we treat all the nine model parameters as unknown in this optimization problem.","Title: Proposed investigations from NASA's Earth Venture-1 (EV-1) airborne science selections\nYear: 2010\n\nAbstract: On 27 May 2010, NASA announced the first Earth Venture (EV-1) selections in response to a recommendation made by the National Research Council for low-cost investigations fostering innovation in Earth Science. The five EV-1 investigations span the Earth science focus areas of atmosphere, weather, climate, water and energy and, carbon and represent Earth science researchers from NASA as well as other government agencies, academia and industry from around the world. The five EV-1 missions are (1) Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS); (2) Airborne Tropical TRopopause Experiment (ATTREX); (3) Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE); (4) Deriving Information on Surface Conditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ), and (5) Hurricane and Severe Storm Sentinel (HS3). The Earth Venture missions are managed out of the Earth System Science Pathfinder (ESSP) Program Office [3]","Title: Inversion of Subsurface Properties of Layered Dielectric Structures With Random Slightly Rough Interfaces Using the Method of Simulated Annealing\nYear: 2009\n\nAbstract: In this paper, the model parameters of a two-layer dielectric structure with random slightly rough boundaries are retrieved from data that consist of the backscattering coefficients for multiple polarizations, angles, and frequencies. We use the small perturbation method to solve the forward problem. The inversion problem is then formulated as a least square problem and is solved using a global optimization method known as simulated annealing, which is shown to be a robust retrieval algorithm for our purpose. The algorithm performance depends on several parameters. We make recommendations on these parameters and propose a technique for exiting local minima when encountered. We test the sensitivity of the inversion scheme to measurement noise and present the noise analysis results.","Title: Ripple-2: a non-collaborative; asynchronous; and open architecture for highly-scalable and low duty-cycle WSNs\nYear: 2013\n\nAbstract: The design of Ripple-2, a wireless in-situ soil moisture sensing system is presented in this paper. The main objective of such system is to collect high fidelity and fine grained data both spatially and temporally compared to radar remote sensing, which is the more traditional way of capturing soil moisture, and to use the former to validate and calibrate the latter. To do so, the in-site sensor network must cover a sufficiently large area, on the order of at least a few square kilometers. At the same time, cost constraints (both in deployment and in maintenance) puts a limit on the total number of sensor nodes, resulting in a very sparse (on average) network. The main challenge in designing the system lies in achieving reliability and energy efficiency in such a sparse network. For instance, in our pilot deployment, a 200mx400m area is covered by 22 nodes (average inter-node distance > 50m). Traditional WSN technology typically calls for many more nodes to be deployed in such an area. Ripple-2 is introduced as a non-traditional WSN architecture where (1) the network is physically and logically segmented into isolated clusters, (2) a regular node (or end device, ED) only communicates with the cluster head (CH) of its segment, and (3) the ED-CH communication is distinct from the CH-sink (or CH-Data Server) and both links can use virtually any kind of point-to-point wireless technology. We use both simulated and empirical results to demonstrate the effectiveness of Ripple-2; it proves to be ideal for low duty-cycle data collection applications due to its exceptional small network overhead (typically smaller than 1%) and its robustness to the size of the network.","Title: WSN-SA: Design foundations for situational awareness systems based on sensor networks.\nYear: 2013\n\nAbstract: WSN-SA is a Wireless Sensor Networks (WSN) framework that is been proposed to support rescue operations in collapsed structures, such as houses and buildings, after natural and human-made disasters. The sensors and actuators are deployed prior to the disaster and ideally such sensor network is a required infrastructure of any building. Such SA systems can help to indicate how to distribute the rescue resources and how to identify imminent risks for rescuers and survivors. So far, few situational awareness (SA) systems based on WSNs have been proposed and no long-term realization of such systems has been reported. The goal of this work is to provide the foundations to change this reality so it would be possible to see a SA system accompanying each existing fire system. To this end, a strong emphasis is given to a) the achievement of low total cost of ownership (TCO), b) reliability, c) and expandability for the adopted SA solution.","Title: Investigating spatial aggregation techniques using a heterogeneous radar landscape simulator for reducing uncertainties of soil moisture retrieval from SMAP.\nYear: 2011\n\nAbstract: In this paper, a heterogeneous landscape simulator is introduced, which will facilitate lifelike forward modeling of various landscapes by taking additional information and ancillary data into account. First results of simple spatial aggregation techniques are discussed and the uncertainty of soil moisture retrieval is quantified. A scaling analysis is performed by investigating above- and below-ground modeling parameters for their influence on the radar model output and their impact on simple aggregation problems.","Title: Radar Retrieval of Surface and Deep Soil Moisture and Effect of Moisture Profile on Inversion Accuracy.\nYear: 2011\n\nAbstract: We study the retrieval of surface and deep moisture of bare soil from noisy radar observations using simulated annealing. Due to moisture variations with depth, we model bare soil with a stratified dielectric profile with a rough surface on top. Small perturbation method (SPM) is used as the forward model. We use the full moisture profile for radar data synthesis and study the retrieval accuracy b...","Title: Microwave breast imaging system prototype with integrated numerical characterization.\nYear: 2012\n\nAbstract: The increasing number of experimental microwave breast imaging systems and the need to properly model them have motivated our development of an integrated numerical characterization technique. We use Ansoft HFSS and a formalism we developed previously to numerically characterize an S-parameter- based breast imaging system and link it to an inverse scattering algorithm. We show successful reconstructions of simple test objects using synthetic and experimental data. We demonstrate the sensitivity of image reconstructions to knowledge of the background dielectric properties and show the limits of the current model.","Title: Microwave Observatory of Subcanopy and Subsurface (MOSS): A Mission Concept for Global Deep Soil Moisture Observations\nYear: 2007\n\nAbstract: The Microwave Observatory of Subcanopy and Subsurface (MOSS) is a mission concept for a spaceborne synthetic aperture radar (SAR) system that provides global observations of soil moisture under substantial vegetation cover (exceeding 20 kg/m2 ) and at useful depths (1-5 m). The concept was developed and a number of new required technologies were demonstrated through a National Aeronautics and Space Administration Earth Science Technology Office Instrument Incubator Program project. This very high frequency (VHF)/ultrahigh frequency (UHF) polarimetric SAR is designed to provide 7-10-day observations of soil moisture at 1-km resolution. The rapid repeat cycle mandates swath widths in the range of 300-400 km, which must be realized by a 30-m-long antenna. Conventional array implementations would result in a mass of more than 4000 kg, whereas with the technology proposed and demonstrated in this project, the total antenna mass is less than 500 kg. The antenna concept is a dual-stacked patch array feed illuminating a 30-m mesh reflector to synthesize the long apertures and achieve the wide swath. The feed system prototype was fabricated and its performance demonstrated. Other major project components were: (1) system-level SAR and mission design; (2) demonstration of science data and products, using a tower-based VHF/UHF radar; (3) spacecraft and mesh reflector antenna mechanical design; (4) developing mitigation strategies for ionospheric effects; and (5) assessing frequency interference effects. Experimental science data were generated from the tower radar for soil moisture profiling in Arizona and for forest penetration in Oregon. The soil moisture products were demonstrated through an integrated inversion-processing algorithm. This paper summarizes the results from the MOSS project and demonstrates the feasibility of the spaceborne mission.","Title: Electromagnetic Scattering From Mutilayer Rough Surfaces Separated By Arbitrary Dielectric Profiles\nYear: 2006\n\nAbstract: Radar remote sensing of soil moisture content at low frequencies requires an accurate scattering model of realistic soils, which often involves multilayer rough surfaces and inhomogeneous dielectric profiles. In this paper, a hybrid analytical/numerical solution to two-dimensional scattering from multilayer rough surfaces separated by arbitrary dielectric profiles based on the extended boundary condition method (EBCM) and scattering matrix technique is presented. The reflection and transmission matrices of a rough interface are constructed using EBCM. The inhomogeneous dielectric profile is modeled as a stack of piecewise homogeneous dielectric thin layers. The scattering matrices of an inhomogeneous dielectric profile are computed by recursively cascading reflection and transmission matrices of individual dielectric interfaces from the bottom dielectric interface to the top interface. The interactions between the rough interfaces and the inhomogeneous dielectric profile are taken into account by applying the generalized scattering matrix technique. In numerical simulations, the actual field-collected soil moisture data are used. In particular, the dielectric profiles during both dry and wet ground conditions are examined. The numerical Simulations are performed to investigate both bistatic scattering coefficients and copolarized phase difference due to different subsurface roughness parameters and ground conditions. Simulation results show that the bistatic scattering coefficients air, low frequencies are sensitive to Subsurface roughness parameters and copolarized phase difference strongly depends on soil moisture contents.","Title: An Adaptive Energy-Management Framework For Sensor Nodes With Constrained Energy Scavenging Profiles\nYear: 2013\n\nAbstract: Modern energy harvesting systems for WSNs involve power scavenging sources, rechargeable batteries, and supercapacitors. Typical energy-management systems calculate/predict the remaining energy stored in a node, and associated actions are dispatched involving the networking protocols. However, long-term characteristics of the mentioned hardware components are typically neglected preventing the achievement of very long maintenance-free lifetimes (e.g., > 5 years) for the nodes. In this work, a systematic analysis of this problem is provided, and an open energy-management framework is proposed which promotes (a) the nontraditional combination of primary cells, supercapacitors, and harvesting systems, (b) the concept of a distributed system inside a node, and (c) the adoption of the dual duty-cycle (DDC) operation for the WSNs. The DDC's core component is a cross-layer protocol implemented as an application-layer overlay which maintains the operation of the network under very high energy efficiency. Its trade-off is the reduction of the network throughput. Therefore, the DDC system has mechanisms that dynamically switch the WSN operational mode according to application's needs. Detailed guidelines are provided in order to allow the implementation of the solution on existing WSN platforms. The energy efficiency of the low duty-cycle mode of the solution is demonstrated by simulated and empirical results.","Title: Power-Management Techniques For Wireless Sensor Networks And Similar Low-Power Communication Devices Based On Nonrechargeable Batteries\nYear: 2012\n\nAbstract: Despite the well-known advantages of communication solutions based on energy harvesting, there are scenarios where the absence of batteries (supercapacitor only) or the use of rechargeable batteries is not a realistic option. Therefore, the alternative is to extend as much as possible the lifetime of primary cells (nonrechargeable batteries). By assuming low duty-cycle applications, three power-management techniques are combined in a novel way to provide an efficient energy solution for wireless sensor networks nodes or similar communication devices powered by primary cells. Accordingly, a customized node is designed and long-term experiments in laboratory and outdoors are realized. Simulated and empirical results show that the battery lifetime can be drastically enhanced. However, two trade-offs are identified: a significant increase of both data latency and hardware/software complexity. Unattended nodes deployed in outdoors under extreme temperatures, buried sensors (underground communication), and nodes embedded in the structure of buildings, bridges, and roads are some of the target scenarios for this work. Part of the provided guidelines can be used to extend the battery lifetime of communication devices in general.","Title: Backscattering Simulation For Nonuniform Forest Canopies Using Multi-Layer Mimics\nYear: 2004\n\nAbstract: In this paper, we introduce a multi-layer MIMICS for nonuniform forest canopies and present the model applications. The Michigan Microwave Canopy Scattering model (MIMICS) has been developed to simulate microwave backscattering from tree canopies. However, the crown-trunk canopy model is too restrictive for nonuniform canopy coverage. Multilayer MIMICS is developed to remove the two-layer canopy restriction. The model is a simulation solution to an array of radiative transfer equations and it includes the layer interactions between overlapping layers. This paper is focused on the model validation and application of multi-layer MIMICS. Our collaborators have supplied us with extensive ground truth data from a 220,000 ha woodland and forest study areas within central Queensland, Australia. The field measurement is at the individual tree level. We can simulate the polarimetric backscattering for the ground measurement. AIRSAR data of the same area are obtained to validate the model simulation. The results show good agreement between the model simulation and SAR measurements. Analyzing an individual layer's contribution offers better understanding of canopy composition effects on backscattering. The multi-layer canopy configuration improves the estimate accuracy over that from a crown-trunk layer model, as in the older version of MIMICS.","Title: A Simulation Study Of Compact Polarimetry For Radar Retrieval Of Soil Moisture\nYear: 2014\n\nAbstract: A compact polarimetric (CP) radar system requires fewer measurements than a fully polarimetric (FP) system, thus allowing added flexibility in radar system design. Previous studies have shown the potential of using compact polarimetry for radar remote sensing of soil moisture. This paper extends previous studies by considering a time series data cube retrieval algorithm and measurements in the presence of vegetation. Vegetation information is assumed to be provided by an ancillary data source in the retrieval process. The performance of an algorithm for reconstructing FP information from CP measurements of vegetated soil surfaces is also examined. The results of the study show that only a modest degradation in soil moisture retrieval performance occurs when compact-pol measurements are used in place of full-pol data.","Title: Two-dimensional full-wave scattering from discrete random media in layered rough surfaces\nYear: 2007\n\nAbstract: Modeling of electromagnetic scattering from discrete random media in layered rough surfaces finds various applications, including depth retrieval of layered snow-covered ice and remote sensing of vegetation canopy. In this paper, a coherent technique for solving scattering from discrete random media in layered rough surfaces is presented. The significance of the development of a full-wave solution to this problem stems from the fact that both co-polarized phase difference and polarized scattering coefficients can only be accurately determined using a coherent approach. Therefore, the objective of this paper is to formulate a full-wave solution for scattering from discrete random media in layered rough surfaces as well as to demonstrate the potential in the retrieval of subsurface parameters pertaining to the physical properties of rough surfaces and discrete random media using polarized scattering coefficients and co- polarized phase difference. The core of our technique lies in the use of plane wave decomposition. Plane wave solution for the scattered field due to a rough surface is obtained using extended boundary condition method (EBCM). The recursive T-matrix algorithm together with cylindrical-waves-to-plane-waves transformation matrices is employed to deal with scattering from discrete random media. Subsequently, plane wave solutions for the scattered fields due to rough surfaces and discrete random media are then cast into reflection and transmission matrices. These reflection and transmission matrices facilitate the application of scattering matrix technique which coherently accounts for electromagnetic interactions between layered rough surfaces and discrete random media. Various numerical results are examined and it is shown that the subsurface parameters may significantly impact backscattering coefficients and co-polarized phase difference even when the subsurface ground is covered by a rough layer of discrete random media.","Title: Deriving soil moisture with the combined L-band radar and radiometer measurements\nYear: 2010\n\nAbstract: In this study, we develop a combined active/passive technique to estimate surface soil moisture with the focus on the short vegetated surfaces. We first simulated a database for both active and passive signals under SMAP's sensor configurations using the radiative transfer model with a wide range of conditions for surface soil moisture, roughness and vegetation properties that we considered as the random orientated disks and cylinders. Using this database, we developed 1) the techniques to estimate surface backscattering and emission components and 2) the technique to estimate soil moisture with the estimated surface backscattering and emission components. We will demonstrate these techniques with the model simulated data and its validation with the airborne PALS image data from the soil moisture SGP'99 and SMEX'02 experiments.","Title: Radiative transfer model for microwave bistatic scattering from forest canopies\nYear: 2005\n\nAbstract: A bistatic forest scattering model is developed to simulate scattering coefficients from forest canopies. The model is based on the Michigan Microwave Canopy Scattering (MIMICS) model (hence called Bi-MIMICS) and uses radiative transfer theory, where the first-order fully polarimetric transformation matrix is used. Bistatic radar systems offer advantages over monostatic radar systems because of the additional information provided by the diversity of the geometry. By simulating the forest canopy scattering from multiple viewpoints, we can better understand how the forest scatterers' shape, orientation, density, and permittivity affect the canopy scattering. Bi-MIMICS is parametrized using selected forest stands with different canopy compositions and structure. The simulation results show that bistatic scattering is more sensitive to forest biomass changes than backscattering. Analyzing scattering contributions from different parts of the canopy gives us a better understanding of the microwave's interaction with the tree components. The ground effects can also be studied. Knowledge of the canopy's bistatic scattering behavior combined with additional synthetic aperture radar measurements can be used to improve forest parameter retrievals. The simulation results of the model provide the required information for the design of future bistatic radar systems for forest sensing applications.","Title: Electromagnetic scattering from arbitrary random rough surfaces using stabilized extended boundary condition method (SEBCM) for remote sensing of soil moisture\nYear: 2010\n\nAbstract: In this paper, the stabilized extended boundary condition method (SEBCM) is developed based on the classical EBCM to solve both 2D and 3D electromagnetic scattering from arbitrary random rough surfaces. The SEBCM gives accurate full wave solutions over large range of surface roughnesses and medium losses, which are far beyond the validity range of analytical methods, and perform with much higher efficiency than numerical methods. These properties make SEBCM a competitive forward model in the inverse problem for soil moisture retrieval from radar measurements.","Title: Large-Domain, Low-Contrast Acoustic Inverse Scattering For Ultrasound Breast Imaging\nYear: 2010\n\nAbstract: We present a full-wave acoustic inverse-scattering algorithm designed specifically for ultrasonic breast imaging. At ultrasonic frequencies, the image domain is roughly tens to hundreds of lambda(min) cubed, where lambda(min) is the smallest wavelength in the transmit signal spectrum. The expected range of contrasts for the breast imaging problem for density, compressibility, and compressive loss is +/- 20% of the background. Because of the low contrast, Born iterations provide the basic structure of the inverse-scattering algorithm. However, we use a multiobjective covariance-based least squares cost function in place of the basic least squares cost function to estimate the contrast functions. This cost function provides physically meaningful regularization based on a priori knowledge of the contrasts. Also, due to the size of the imaging domain and because the objects to be imaged are low contrast and inhomogeneous, we use the Neumann series solution as the forward solver. The largest domain imaged in simulation was 50 lambda(min) X 50 lambda(min) in 2-D.","Title: Guest EditorialSpecial Section on the 2007 International Conference on Near-Field Imaging and Characterization (ICONIC'07)\nYear: 2008\n\nAbstract: The four papers in this special section present a sparse but diverse sampling of some of the prominent near-field imaging techniques for very different applications.","Title: ADvances in radar forward and inverse scattering models of subsurface and subcanopy soil moisture and their role for the AirMOSS mission\nYear: 2012\n\nAbstract: The Airborne Observatory of Subcanopy and Subsurface (AirMOSS) is one of the five Earth Venture-1 missions selected in May 2010, and seeks to improve the estimates of the north American net ecosystem carbon exchange (NEE) through high-resolution observations of root zone soil moisture (RZSM). To obtain estimates of RZSM and assess its heterogeneities, AirMOSS will fly a P-band (430 MHz) synthetic aperture radar (SAR) over 2500 km2 areas within nine major biomes of north America. Retrieval of RZSM in the presence of substantial vegetation requires the construction of accurate radar scattering models that account for diverse vegetation conditions as well as subsurface inhomogeneities. In this paper we provide a summary of recent advances in this area, emphasizing several coherent and incoherent models of scattering from multilayered inhomogeneous rough surfaces, as well as strategies for using these forward models in retrieval algorithms.","Title: Electromagnetic scattering from multilayer rough surfaces based on extended boundary condition formulation and transition matrix approach\nYear: 2005\n\nAbstract: The electromagnetic scattering of rough surface has been investigated extensively for the past decades. There exist analytical solutions to rough surface scattering such as small perturbation method (SPM) or Kirchhoff approximation (KA). These analytical solutions, however, are limited to either small or large roughness regimes. Recent efforts have been put forth to study scattering from multilayer rough surface in the application of deep soil moisture estimation. In this paper, multilayer rough surface scattering is analyzed based on an approach which combines extended boundary condition formulation (EBC) and transition matrix method. From the Floquet theorem, the Floquet modes translate into the coherent reflection and transmission coefficients in their corresponding scattering directions. To account for coherent multiple interactions between rough surface layers, transition matrix approach is used. Each Floquet mode direction is considered a port of a multiport system and network theory is used to characterize cascaded rough surface layers. Bistatic scattering coefficients are then obtained by incoherently averaging the power computed from the resultant Floquet modes in the scattering directions. Therefore, the electromagnetic wave interactions in multilayer rough surfaces are analyzed in a very efficient way by applying EBC to each rough surface and then cascading iteratively transition matrix of each layer interface. Finally, the results are validated against the analytical SPM solution to two-layer rough surface scattering.","Title: Radar backscattering model for multilayer mixed-species forests\nYear: 2005\n\nAbstract: A multilayer canopy scattering model is developed for mixed-species forests. The multilayer model provides a significantly enhanced representation of actual complex forest structures compared to the conventional canopy-trunk layer models. Multilayer Michigan Microwave Canopy Scattering model (Multi-MIMICS) allows overlapping layer configuration and a tapered trunk model applicable to forests of mixed species and/or mixed growth stages. The model is the first-order solution to a set of radiative transfer equations and includes layer interactions between overlapping layers. It simulates SAR backscattering coefficients based on input dimensional, geometrical, and dielectric variables of forest canopies. The Multi-MIMICS is an efficient realization of actual forest structures and can be shaped for specific interest of forest parameters. We present the model's application and validation in the paper. The model is parameterized using data collected from a 220,000-ha area of forests in central Queensland, Australia. Fifteen 50×50 m test sites representing the general forest diversity and growth stages are chosen as ground truth. Polarimetric backscattering airborne SAR (AIRSAR) data of the same area are acquired to validate the model simulations. The model predicts SAR backscattering coefficients of the test areas. Simulation results show a good agreement with AIRSAR data at most frequencies and polarizations. The simulated backscattering coefficient from the multilayer model and the standard MIMICS are also compared and significant improvements are observed.","Title: Electromagnetic scattering from multilayer rough surfaces with arbitrary dielectric profiles for remote sensing of subsurface soil moisture\nYear: 2007\n\nAbstract: Radar remote sensing of soil moisture content at low frequencies requires an accurate scattering model of realistic soils, which often involves multilayer rough surfaces and inhomogeneous dielectric profiles. In this paper, a hybrid analytical/numerical solution to two- dimensional scattering from multilayer rough surfaces separated by arbitrary dielectric profiles based on the extended boundary condition method (EBCM) and scattering matrix technique is presented. The reflection and transmission matrices of a rough interface are constructed using EBCM. The inhomogeneous dielectric profile is modeled as a stack of piecewise homogeneous dielectric thin layers. The scattering matrices of an inhomogeneous dielectric profile are computed by recursively cascading reflection and transmission matrices of individual dielectric interfaces. The interactions between the rough interfaces and the inhomogeneous dielectric profile are accounted for by applying the generalized scattering matrix technique. The solution presented in this paper is for the two-dimensional scenario of multilayer rough surfaces. The technique can also be applied in three dimensions. In numerical simulations, the actual field-collected soil moisture data are used. In particular, the dielectric profiles during both dry and wet ground conditions are examined. The numerical simulations are performed to investigate both backscattering scattering coefficients and co- polarized phase difference due to different subsurface roughness parameters and ground conditions. The results show that both backscattering coefficients and co-polarized phase difference at low frequencies are sensitive to the roughness of subsurface interfaces and deep soil moisture. Also, much larger depth sensitivity can be achieved using co-polarized phase difference than scattering coefficients.","Title: Models of L-Band Radar Backscattering Coefficients Over Global Terrain for Soil Moisture Retrieval\nYear: 2014\n\nAbstract: Physical models for radar backscattering coefficients are developed for the global land surface at L-band (1.26 GHz) and 40 ° incidence angle to apply to the soil moisture retrieval from the upcoming soil moisture active passive mission data. The simulation of land surface classes includes 12 vegetation types defined by the International Geosphere-Biosphere Programme scheme, and four major crops (wheat, corn, rice, and soybean). Backscattering coefficients for four polarizations (HH/VV/HV/350611873VH) are produced. In the physical models, three terms are considered within the framework of distorted Born approximation: surface scattering, double-bounce volume-surface interaction, and volume scattering. Numerical solutions of Maxwell equations as well as theoretical models are used for surface scattering, double-bounce reflectivity, and volume scattering of a single scatterer. To facilitate fast, real-time, and accurate inversion of soil moisture, the outputs of physical model are provided as lookup tables (with three axes; therefore called datacube). The three axes are the real part of the dielectric constant of soil, soil surface root mean square (RMS) height, and vegetation water content (VWC), each of, which covers the wide range of natural conditions. Datacubes for most of the classes are simulated using input parameters from in situ and airborne observations. This simulation results are found accurate to the co-pol RMS errors of to 3.4 dB (six woody vegetation types), 1.8 dB (grass), and 2.9 dB (corn) when compared with airborne data. Validated with independent spaceborne phased array type L-band synthetic aperture radars and field-based radar data, the datacube errors for the co-pols are within 3.4 dB (woody savanna and shrub) and 1.5 dB (bare surface). Assessed with spaceborne Aquarius scatterometer data, the mean differences range from ~ 1.5 to 2 dB. The datacubes allow direct inversion of sophisticated forward models without empirical par- meters or formulae. This capability is evaluated using the time-series inversion algorithm over grass fields.","Title: Potential of L-Band Radar for Retrieval of Canopy and Subcanopy Parameters of Boreal Forests.\nYear: 2012\n\nAbstract: In this paper, we study the radar retrieval of soil moisture as well as canopy parameters in a range of boreal forests. The retrieval is formulated as an optimization problem where the difference between data and prediction of a forward scattering model is minimized. The forward model is a discrete scatterer radar model, and the optimization algorithm is a global optimization scheme known as simul...","Title: Estimation of crown and stem water content and biomass of boreal forest using polarimetric SAR imagery\nYear: 2000\n\nAbstract: Characterization of boreal forests in ecosystem models requires temporal and spatial distributions of water content and biomass over local and regional scales. The authors report on the use of a semi-empirical algorithm for deriving these parameters from polarimetric synthetic aperture radar (SAR) measurements. The algorithm is based on a two layer radar backscatter model that stratifies the forest canopy into crown and stem layers and separates the structural and biometric attributes of forest stands. The structural parameters are estimated by training the model with SAR image data over dominant coniferous and deciduous stands in the boreal forest such as jack pine, black spruce, and aspen. The algorithm is then applied on AIRSAR images collected during the Boreal Ecosystem Atmospheric Study (BOREAS) over the boreal forest of Canada. The results are verified using biometry measurements during BOREAS-intensive field campaigns. Field data relating the water content of tree components to dry biomass are used to modify the coefficients of the algorithm for crown and stem biomass. The algorithm was then applied over the entire image generating biomass maps. A set of 18 test sites within the imaged area was used to assess the accuracy of the biomass maps. The accuracy of biomass estimation is also investigated by choosing different combinations of polarization and frequency channels of the AIRSAR system. It is shown that polarimetric data from P-band and L-band channels provide similar accuracy for estimating the above-ground biomass for boreal forest types. In general, the use of P-band channels can provide better estimates of stem biomass, while L-band channels can estimate the crown biomass more accurately","Title: Bistatic Vector 3-D Scattering From Layered Rough Surfaces Using Stabilized Extended Boundary Condition Method.\nYear: 2013\n\nAbstract: A model of 3-D electromagnetic scattering from multiple rough surfaces within homogeneous-layered or vertically inhomogeneous media is developed in this work. This model, aimed at radar remote sensing of surface-to-depth profiles of soil moisture, computes total bistatic radar cross sections from the multilayer structure based on the scattering matrix approach, cascading the scattering matrices of...","Title: 3-D Vector Electromagnetic Scattering From Arbitrary Random Rough Surfaces Using Stabilized Extended Boundary Condition Method for Remote Sensing of Soil Moisture\nYear: 2012\n\nAbstract: We develop the stabilized extended boundary condition method (SEBCM) based on the classical EBCM to solve the 3-D vector electromagnetic scattering problem from arbitrary random rough surfaces. Similar to the classical EBCM, we expand the fields in terms of Floquet modes and match the extended boundary conditions at test surfaces away from the actual rough surface to retrieve the surface currents and therefore the scattered fields. However, to solve long-standing stability problems of the classical EBCM, we introduce a z-coordinate transformation to restrict and control the test surface locations explicitly. We also introduce the concepts of moderated test surface locations and balanced k-charts for further stabilization and optimization of the solutions. The computational efficiency is optimized by judicious submatrix decomposition. The resulting bistatic scattering cross sections are validated by comparing with analytical and numerical solutions. Specifically, the solutions are compared with those from the small perturbation method and small-slope approximation within their validity region, and with those from the method of moments outside the validity domains of analytical solutions. It is shown that SEBCM gives accurate, numerically efficient, full-wave solutions over a large range of surface roughnesses and medium losses, which are far beyond the validity range of analytical methods. These properties are expected to make SEBCM a competitive forward solver for soil moisture retrieval from radar measurements.","Title: Analysis of scattering mechanisms in SAR imagery over boreal forest: results from BOREAS '93\nYear: 1995\n\nAbstract: As part of the intensive field campaign (IFC) for the Boreal forest ecosystem-atmosphere research (BOREAS) project in August 1993, the NASA/JPL AIRSAR covered an area of about 100 km×100 km near the Prince Albert National Park in Saskatchewan, Canada. At the same time, ground-truth measurements were made in several stands which have been selected as the primary study sites. This paper focuses on an area including jack pine stands in the Nipawin area near the park. Upon examining the AIRSAR data from stands of old and young jack pine (OJP and YJP), distinct signatures are observed for each of the forest types at various frequencies and polarizations, in particular, at P-band HH. The authors use a forest scattering model in conjunction with the ground-truth measurements to explain such behavior. The forest model includes the major scattering mechanisms by taking the forest component interactions into account. The contribution from each of the scattering mechanisms to the total backscatter is calculated and their differences for OJP and YJP stands are evaluated. The results are used to discuss the effect of the physical properties of the forest components in each stand on radar backscatter. They are also used to show that it is not only the backscatter level but also the relative contribution from various scattering mechanisms that will help in quantitative interpretation of SAR data. This work is mainly intended as a precursor to the authors ongoing work which uses a mechanism-specific inversion technique to retrieve forest parameters from SAR data for these BOREAS sites","Title: Inversion Of A Layered Rough Surface Model: Maximizing The Number Of Retrievable Parameters For The Design Of Future Subsurface Sensing Radar Systems\nYear: 2007\n\nAbstract: We previously applied an optimization technique known as Simulated Annealing (SA) to the inverse problem associated with a 31) two-layer dielectric structure with slightly rough interfaces and showed that simulated annealing methods are capable of globally minimizing cost functions with many local minima [1]. Nonlinearity of the cost function is a major factor that decreases the performance of the inversion algorithm. With a fixed set of measurement and inversion parameters, as the number of unknown model parameters increases, the cost function nonlinearity becomes more severe, decreasing the efficiency of inversion and making the annealing process perform like an inefficient brute force search. The focus of this work is on strategies to choose the optimal set of measurement parameters for retrieval of the largest possible number of parameters of a layered dielectric structure.","Title: Study of Validity Region of Small Perturbation Method for Two-Layer Rough Surfaces\nYear: 2010\n\nAbstract: We previously derived the bistatic scattering coefficients of a 3-D two-layer dielectric structure with slightly rough boundaries using the small perturbation method (SPM). The use of SPM raises the question about its region of validity, which pertains to the conditions on each layer roughness, slope, and permittivity for which the first-order SPM is accurate within a specified error bound. To thi...","Title: A Wireless Soil Moisture Smart Sensor Web Using Physics-Based Optimal Control: Concept and Initial Demonstrations\nYear: 2010\n\nAbstract: This paper introduces a new concept for a smart wireless sensor web technology for optimal measurements of surface-to-depth profiles of soil moisture using in-situ sensors. The objective of the technology, supported by the NASA Earth Science Technology Office Advanced Information Systems Technology program, is to enable a guided and adaptive sampling strategy for the in-situ sensor network to meet the measurement validation objectives of spaceborne soil moisture sensors. A potential application for this technology is the validation of products from the Soil Moisture Active/Passive (SMAP) mission. Spatially, the total variability in soil-moisture fields comes from variability in processes on various scales. Temporally, variability is caused by external forcings, landscape heterogeneity, and antecedent conditions. Installing a dense in-situ network to sample the field continuously in time for all ranges of variability is impractical. However, a sparser but smarter network with an optimized measurement schedule can provide the validation estimates by operating in a guided fashion with guidance from its own sparse measurements. The feedback and control take place in the context of a dynamic physics-based hydrologic and sensor modeling system. The overall design of the smart sensor web-including the control architecture, physics-based hydrologic and sensor models, and actuation and communication hardware-is presented in this paper. We also present results illustrating sensor scheduling and estimation strategies as well as initial numerical and field demonstrations of the sensor web concept. It is shown that the coordinated operation of sensors through the control policy results in substantial savings in resource usage.","Title: Classification of Alaska Spring Thaw Characteristics Using Satellite L-Band Radar Remote Sensing\nYear: 2015\n\nAbstract: Spatial and temporal variability in landscape freeze- thaw (FT) status at higher latitudes and elevations significantly impacts land surface water mobility and surface energy partitioning, with major consequences for regional climate, hydrological, ecological, and biogeochemical processes. With the development of new-generation spaceborne remote sensing instruments, future L-band missions, including the NASA Soil Moisture Active and Passive mission, will provide new operational retrievals of landscape FT state dynamics at moderate (~3 km) spatial resolution. We applied theoretical simulations of L-band radar backscatter using first-order radiative transfer models with two and three-layer modeling schemes to develop a modified seasonal threshold algorithm (STA) and FT classification study over Alaska using 100-m-resolution satellite Phased Array L-band Synthetic Aperture Radar (PALSAR) observations. The backscatter threshold distinguishes between frozen and nonfrozen states, and it is used to classify the predominant frozen or thawed status of a grid cell. An Alaska FT map for April 2007 was generated from PALSAR (ScanSAR) observations and showed a regionally consistent but finer FT spatial pattern than an alternative surface air temperature-based classification derived from global reanalysis data. Validation of the STA-based FT classification against regional soil climate stations indicated approximately 80% and 75% spatial classification accuracy values in relation to respective station air temperature and soil temperature measurement-based FT estimates. An investigation of relative spatial scale effects on FT classification accuracy indicates that the relationship between grid cell size and classified frozen or thawed area follows a general logarithmic function.","Title: A Combined Active–Passive Soil Moisture Estimation Algorithm With Adaptive Regularization in Support of SMAP\nYear: 2015\n\nAbstract: We present a method to combine same-resolution measurements of active radar and passive radiometer microwave remote sensing to build a framework for soil moisture estimation in support of the Soil Moisture Active and Passive (SMAP) mission. A unified active-passive soil moisture estimation algorithm is developed within a global optimization scheme, using a joint cost function with adaptive regularization, where, unlike traditional methods, both radar and radiometer measurements are utilized at the same time to retrieve soil moisture. Monte Carlo numerical simulations and optimization to retrieve soil moisture are performed for Corn, Soybean, and Grass landcover types for active-only, passive-only, and active-passive scenarios. These numerical experiments show that the proposed combined active-passive (CAP) soil moisture estimation approach outperforms either the single-sensor technique, particularly for higher vegetation water content (VWC) values (VWC > 3 kg/m2). For example, for the case of Corn with VWC of 5 kg/m2, retrieval error is reduced to 0.035 cm3/cm3 for the active-passive method from 0.08 cm3/cm3 for active scenarios. Furthermore, tests of this new algorithm on the Passive and Active Land S-band Sensor (PALS) Soil Moisture Experiment 2002 (SMEX02), as well as the Combined RadarRadiometer (ComRad) collocated active and passive data, demonstrate the applicability of this method to actual data, even with potentially inaccurate forward models and noisy data. Results indicate that the best soil moisture estimates over a large range of soil moisture (0.04-0.4 cm3/cm3) and vegetation (0-5 kg/m2) conditions are achievable when the adaptive regularization parameter γ is chosen to give slightly more weight to the radiometer forward model without discarding the complementary radar measurement points.","Title: P-Band Radar Retrieval of Subsurface Soil Moisture Profile as a Second-Order Polynomial: First AirMOSS Results\nYear: 2015\n\nAbstract: We propose a new model for estimating subsurface soil moisture using P-band radar data over barren, shrubland, and vegetated terrains. The unknown soil moisture profile is assumed to have a second-order polynomial form as a function of subsurface depth with three unknown coefficients that we estimate using the simulated annealing algorithm. These retrieved coefficients produce the value of soil moisture at any given depth up to a prescribed depth of validity. We use a discrete scattering model to calculate the radar backscattering coefficients of the terrain. The retrieval method is tested and developed with synthetic radar data and is validated with measured radar data and in situ soil moisture measurements. Both forward and inverse models are briefly explained. The radar data used in this paper have been collected during the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission flights in September and October of 2012 over a 100 km by 25 km area in Arizona, including the Walnut Gulch Experimental Watershed. The study area and the ancillary data layers used to characterize each radar pixel are explained. The inversion results are presented, and it is shown that the RMSE between the retrieved and measured soil moisture profiles ranges from 0.060 to 0.099 m3/m3, with a Root Mean Squared Error (RMSE) of 0.075 m3/m3 over all sites and all acquisition dates. We show that the accuracy of retrievals decreases as depth increases. The profiles used in validation are from a fairy dry season in Walnut Gulch and so are the accuracy conclusions.","Title: The Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12): Prelaunch Calibration and Validation of the SMAP Soil Moisture Algorithms\nYear: 2015\n\nAbstract: The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite is scheduled for launch in January 2015. In order to develop robust soil moisture retrieval algorithms that fully exploit the unique capabilities of SMAP, algorithm developers had identified a need for long-duration combined active and passive L-band microwave observations. In response to this need, a joint Canada-U.S. field experiment (SMAPVEX12) was conducted in Manitoba (Canada) over a six-week period in 2012. Several times per week, NASA flew two aircraft carrying instruments that could simulate the observations the SMAP satellite would provide. Ground crews collected soil moisture data, crop measurements, and biomass samples in support of this campaign. The objective of SMAPVEX12 was to support the development, enhancement, and testing of SMAP soil moisture retrieval algorithms. This paper details the airborne and field data collection as well as data calibration and analysis. Early results from the SMAP active radar retrieval methods are presented and demonstrate that relative and absolute soil moisture can be delivered by this approach. Passive active L-band sensor (PALS) antenna temperatures and reflectivity, as well as backscatter, closely follow dry down and wetting events observed during SMAPVEX12. The SMAPVEX12 experiment was highly successful in achieving its objectives and provides a unique and valuable data set that will advance algorithm development.","Title: Generalized radar scattering model including terrain topography\nYear: 2014\n\nAbstract: Terrain topography is of great importance for vegetated areas given that even small slopes impact and alter the radar wave interactions between the ground and the overlying vegetation. Current missions generally exclude pixels with large topographic slopes or disregard the terrain topography entirely, potentially accumulating substantial modeling errors and therefore impacting the retrieval performance over such sloped pixels. A flexible and modular radar scattering model has been developed: it describes multispecies vegetation over an N-layered soil with rough interfaces and considers a two-dimensional slope. Simulation results show the impact of a two-dimensional slope for a range of tilt angles: a 3 degree tilt in the plane of incidence translates to a change of up to 6 dB in HH, 2 dB in VV and 1 dB in HV for the total radar backscatter. The terrain topography is shown to be crucial for accurate forward modeling, especially over forested areas.","Title: Mitigation of Faraday rotation effect for long-wavelength synthetic spaceborne radar data\nYear: 2014\n\nAbstract: The focus for geophysical parameter retrieval from space, such as soil moisture, is shifting towards lower frequencies allowing better penetration through vegetation (rendering it less visible) and into the soil (allowing soil moisture sensing into depth). But the ionosphere becomes increasingly opaque at lower frequencies, which intensifies the need for mitigation of ionospheric effects to allow the use of spaceborne radar signals. This work focuses on a radar-only method to predict and mitigate the Faraday rotation effect, which is considered to be the remaining dominant effect. A novel method to retrieve the Faraday rotation angle by using three different optimization techniques in the presence of other system distortion terms with no external targets is presented. The retrieval performance with synthetic spaceborne radar data is very promising; it allows a successful retrieval of the Faraday rotation angle if it is initiated within ±25° of the ground truth.","Title: Radar-radiometer soil moisture estimation with joint physics and adaptive regularization in support of SMAP\nYear: 2014\n\nAbstract: A combined radar-radiometer soil moisture estimation framework is presented in this work, which utilizes both radar backscatter and radiometer brightness temperature using physics-based models that fundamentally couple the scattering and emission processes. A regularization or tuning parameter is introduced within the optimization algorithm to enable flexibility and adaptability. It is observed that by finding the right balance between radar and radiometer contributions within a “joint” cost function, best estimates over a larger range of surface soil moisture and roughness are achievable. Monte Carlo numerical simulations are performed to highlight how this novel Active-Passive method is capable of fully utilizing emission and scattering sensitivities to surface soil moisture.","Title: The Effect of Variable Soil Moisture Profiles on P-Band Backscatter\nYear: 2014\n\nAbstract: Radar measurements at P-band are sensitive to profile soil moisture. Associated backscatter measurements depend on the distribution and variation of the soil moisture profile. Existing scattering models account for this variation by approximating the soil moisture profile as consisting of a number of homogeneous layers. Since the inversion of the scattering models during the retrieval process can be based on only a few polarimetric backscatter measurements, the number of obtainable independent layers in the profile representation is limited. The purpose of this paper is to gain insights into the effects of the layering representation on the resulting modeled forward scattering. These insights form the rational basis for the design of retrieval algorithms. The effects of reflections between layers and other sources of error on simulated backscattering coefficients are first illustrated using several case studies. To determine the combined effect of different error sources for realistic soil moisture profiles, ten years of conditions at a grassland in California are studied. Depending on the layering strategy and the polarization, the root-mean-square error (RMSE) of backscattering coefficients due to misrepresenting the profile alone can be up to 2 dB, although errors can be up to 10 dB in particular cases. The error generally decreases as additional layers are added. The HH-polarization is more sensitive to the subsurface than the VV-polarization and has greater errors. Using a profile-dependent layer placement strategy decreases the RMSE of the backscatter simulation by less than 1 dB relative to a strategy with fixed layering.","Title: On the Accuracy of Averaging Radar Backscattering Coefficients for Bare Soils Using the Finite-Element Method\nYear: 2014\n\nAbstract: Radar backscattering coefficients for heterogeneous pixels are traditionally assumed to be the average of the coefficients for the constitutive homogeneous pixels. We investigate the validity of this assumption for bare rough surfaces by using the 2-D finite-element method to compute the ensemble averaged “true” coefficients for heterogeneous pixels and compare these values with the computed averages for a variety of surfaces. We quantify the impact of heterogeneity in both soil moisture and surface roughness on the averaging assumption. We find that the validity of the assumption rests crucially on the surface correlation type (exponential or Gaussian) and length. In particular, when considering pixels with either heterogeneous soil moisture or roughness, we find that for high-contrast pixels, the backscatter averaging assumption breaks down by as much as 11 dB for Gaussian correlated surfaces for the longest correlation lengths considered (regardless of the source of heterogeneity), whereas for exponentially correlated surfaces, it breaks down by 6 dB for pixels with heterogeneous roughness and 2 dB for pixels with heterogeneous moisture. We attribute this behavior to Gaussian correlated surfaces possessing higher cross-pixel coherent interactions. Furthermore, conditions of validity for the backscatter averaging assumption are identified.","Title: Real-time Microwave Imaging of Differential Temperature for Thermal Therapy Monitoring\nYear: 2014\n\nAbstract: A microwave imaging system for real-time 3-D imaging of differential temperature has been developed for the monitoring and feedback of thermal therapy systems. Design parameters are constrained by features of a prototype-focused microwave thermal therapy system for the breast, operating at 915 MHz. Real-time imaging is accomplished with a precomputed linear inverse scattering solution combined with continuous vector network analyzer (VNA) measurements of a 36-antenna, HFSS-modeled, cylindrical cavity. Volumetric images of differential change of dielectric constant due to temperature are formed with a refresh rate as fast as 1 frame/s and 1 (°)C resolution. Procedures for data segmentation and postprocessed S-parameter error-correction are developed. Antenna pair VNA calibration is accelerated by using the cavity as the unknown thru standard. The device is tested on water targets and a simple breast phantom. Differentially heated targets are successfully imaged in cluttered environments. The rate of change of scattering contrast magnitude correlates 1:1 with target temperature.","Title: An integrated active-passive soil moisture retrieval algorithm for SMAP for bare surfaces\nYear: 2012\n\nAbstract: An integrated soil moisture retrieval algorithm is presented in this work wherein both radar and radiometer measurements are used simultaneously to retrieve surface soil moisture. This method is applied to bare rough surfaces with varying soil moisture and roughness distributions. A thresholding method based on physical models of scattering and emission is presented to obtain equivalent estimated brightness temperatures from active radar measurements. This technique is used as a constraint to link active and passive data within the optimization scheme. Numerical simulations are performed to investigate the proposed inversion technique using the method of Simulated Annealing.","Title: The effects of noise on model inversion for the retrieval of forest structure from SAR data\nYear: 2012\n\nAbstract: The inversion of physics based models presents an alternative to empirical relationships for the retrieval of forest structure from Synthetic Aperture Radar (SAR) data. A major disadvantage of such techniques is instability in the presence of moderate levels of noise. The effects of noise on the accuracy with which parameters can be retrieved is evaluated in this study under a number of conditions.","Title: A generalized radar scattering model for multispecies forests with multilayer subsurface soil\nYear: 2012\n\nAbstract: A generalized radar scattering model to predict backscattering for different frequencies and polarizations is crucial in the endeavor to understand the relationship between radar measurement and properties of both the vegetation and soil, and for allowing the estimation of both vegetation and soil information from radar data. In this work, we develop a combined radar scattering model of vegetation and multilayered soil structure to represent realistic soils with multiple layers of various textures, depths, and moisture contents. A multilayered soil scattering model based on first order small perturbation method (SPM) is integrated [1] to account for direct ground scattering. Furthermore, the coherent interaction between the vegetation and layered ground is included using a recently developed model based on the Kirchhoff approximation [2].","Title: Backscattering of electromagnetic waves from layered rough surfaces and its application in estimating deep soil moisture\nYear: 2004\n\nAbstract: An analytical method to calculate the scattering coefficients of a three-layer 3D rough surface is introduced. The two rough interfaces are assumed to be distinct. The waves in each region are represented as a superposition of an infinite number of up- and down-going spectral wave components, whose amplitudes are found by applying the boundary conditions. A small-perturbation formulation is used in the process and the scattering coefficients are derived to the first order. The formulation is validated against known solutions for special cases of flat interfaces as well as the single rough surfaces. Results are then generated for several cases of the three-layer rough interface medium, to be used for modeling of the backscattered signals from a tower-based radar system and subsequent estimation of multilayered soil properties such as moisture content and subsurface layer height","Title: The MOSS VHF/UHF spaceborne SAR system testbed\nYear: 2005\n\nAbstract: Summary form only given. This paper details our recent development of a system prototype for a spaceborne sensor that addresses the current NASA science priority of measuring soil moisture \"under a substantial vegetation canopy and reaching a useful depth within the uppermost soil layer\". The mission is named MOSS, for the Microwave Observatory of Subcanopy and Subsurface. It will enable measurement and derivation of data products not obtained from any other current, planned, or proposed instrument, with a solution that offers high science value through a low-mass and, in the long-term, low-cost approach. The proposed system is a spaceborne synthetic aperture radar (SAR) operating at the two low frequencies of 435 MHz (UHF, P-band) and 137 MHz (VHF) to enable sensing through vegetation and down into soil. The future mission scenario is achieved from a Sun synchronous orbit of 1313 km altitude, with a swath width of 430 km, incidence angle ranges of 17-30 degrees, resolution of 1 km, and a 7-day exact repeat consistent with the temporal scale of variations of the subcanopy and subsurface soil moisture. We describe a tower-based test-bed that we have developed to validate the spaceborne measurement concept. The processing software, including polarimetric calibration aspects, is detailed, and example science products are presented. The procedures and algorithms to estimate subsurface moisture are presented in detail, and the use an iterative estimation procedure is explained. The results are validated by comparing against detailed ground truth.","Title: A Generalized Radar Backscattering Model Based on Wave Theory for Multilayer Multispecies Vegetation\nYear: 2011\n\nAbstract: A generalized radar scattering model based on wave theory is described. The model predicts polarimetric radar backscattering coefficients for structurally complex vegetation comprised of multiple species and layers. Compared to conventional two-layer crown-trunk models, modeling of actual forests has been improved substantially, allowing better understanding of microwave interaction with vegetation. The model generalizes an existing single-species discrete scatterer model and, by including scattering and propagation effects through judiciously defined vegetation layers, enables its application to an arbitrary number of species types. The scatterers within each layer are modeled as finite cylinders or disks having arbitrary size, density, and orientation, as in the predecessor model. The distorted Born approximation is used to represent the propagation through each layer, while scattering from each is modeled as a linear superposition of scattering from its respective random collection of scatterers. Interactions of waves within and between each layer and direct scattering from the ground are accounted for. Validation of the model is presented based on its application to 23 wooded savanna sites located in Queensland, Australia, and comparison with Advanced Land Observing Satellite (ALOS) Phased Arrayed L-band Synthetic Aperture Radar (PALSAR) and National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) data. Results indicate good agreement between simulated and actual backscattering coefficients, particularly at HH and VV polarizations. More discrepancies are found at HV polarizations and can be explained by uncertainties in the knowledge of input parameters, such as inaccuracies in the surface model, surface roughness parameterization, and soil moisture.","Title: A Preclinical System Prototype for Focused Microwave Thermal Therapy of the Breast\nYear: 2012\n\nAbstract: A preclinical prototype of a transcutaneous thermal therapy system has been developed for the targeted treatment of breast cancer cells using focused microwaves as an adjuvant to radiation, chemotherapy, and high-intensity-focused ultrasound. The prototype system employs a 2-D array of tapered microstrip patch antennas operating at 915 MHz to focus continuous-wave microwave energy transcutaneously into the pendent breast suspended in a coupling medium. Prior imaging studies are used to ascertain the material properties of the breast tissue, and these data are incorporated into a multiphysics model. Time-reversal techniques are employed to find a solution (relative amplitudes and phase) for focusing at a given location. Modeling tests of this time-reversal focusing method have been performed, which demonstrate good targeting accuracy within heterogeneous breast tissue. Experimental results using the laboratory prototype to perform focused heating in tissue-mimicking gelatin phantoms have demonstrated 1.5-cm-diameter focal spot sizes and differential heating at the desired focus sufficient to achieve an antitumor effect confined to the target region.","Title: Comparison of Gaussian and Rayleigh noise models in inversion of subsurface parameters of layered rough surfaces using simulated annealing\nYear: 2009\n\nAbstract: This work addresses the noise sensitivity of the simulated annealing method in inversion of subsurface parameters of layered rough surfaces to measurement noise. We consider two different noise models and assess the noise response of the inversion algorithm for each of the models. Conclusions are made based on the calculated average and standard deviation of the output error in the retrieved model parameters.","Title: Measurement Scheduling for Soil Moisture Sensing: From Physical Models to Optimal Control\nYear: 2010\n\nAbstract: In this paper, we consider the problem of monitoring soil moisture evolution using a wireless network of in situ sensors. Continuously sampling moisture levels with these sensors incurs high-maintenance and energy consumption costs, which are particularly undesirable for wireless networks. Our main hypothesis is that a sparser set of measurements can meet the monitoring objectives in an energy-efficient manner. The underlying idea is that we can trade off some inaccuracy in estimating soil moisture evolution for a significant reduction in energy consumption. We investigate how to dynamically schedule the sensor measurements so as to balance this tradeoff. Unlike many prior studies on sensor scheduling that make generic assumptions on the statistics of the observed phenomenon, we obtain statistics of soil moisture evolution from a physical model. We formulate the optimal measurement scheduling and estimation problem as a partially observable Markov decision problem (POMDP). We then utilize special features of the problem to approximate the POMDP by a computationally simpler finite-state Markov decision problem (MDP). The result is a scalable, implementable technology that we have tested and validated numerically and in the field.","Title: Radar retrieval of subsurface parameters for layered media with nonsmooth interfaces\nYear: 2010\n\nAbstract: The solution to the inverse problem for a three-layer medium representing a large class of natural subsurface structures is developed in this paper using radar data. The retrieval of the layered medium parameters is accomplished as a sequential nonlinear optimization starting from the top layer and progressively characterizing the layers below. The optimization process is accomplished by an efficient iterative technique built around the solution of the forward scattering problem. The forward scattering process is formulated by using the Extended Boundary Condition Method (EBCM) and constructing reflection and transmission matrices for each interface. These matrices are then combined into the generalized scattering matrix for the entire system, from which radar scattering coefficients are then computed. To be efficiently utilized in the inverse problem, the forward scattering model is simulated over a wide range of unknowns to obtain a complete set of subspace-based equivalent closed form models that relate radar cross section coefficients to the sought-for parameters including dielectric constants of each layer and separation of the layers. The inversion algorithm is implemented as a modified conjugate-gradient-based nonlinear optimization. It is assumed that multifrequency radar measurements are available from tower-mounted or airborne platforms, for example at typical radar frequencies of L-band and P-band (UHF). It is shown that this technique results in accurate retrieval of surface and subsurface parameters, even in the presence of noise.","Title: A radar-radiometer surface soil moisture retrieval algorithm for SMAP\nYear: 2013\n\nAbstract: A soil moisture retrieval algorithm is presented whereby both radar and radiometer measurements are used simultaneously in an optimization scheme to retrieve for surface soil moisture in the presence of vegetation. Further, using fine-resolution radar measurements, a disaggregated brightness temperature product at the radar resolution is developed to reconcile the spatial resolution discrepancy between the two measurements. Numerical simulations are performed to synthesize SMAP data, and then via the method of Simulated Annealing, optimization is accomplished to retrieve high resolution soil moisture.","Title: 3D SAR focusing for subsurface point targets\nYear: 2009\n\nAbstract: In this work we develop a methodology for imaging subsurface point targets using a single-pass strip-map synthetic aperture radar (SAR). The point targets are embedded in an arbitrary homogeneous half space, and are located at arbitrary depths. It is assumed that the radar frequency is low enough and system sensitivity high enough to allow the required two-way penetration depth to target. The succession of steps required to form the image of the subsurface point targets are described, including the estimation of the subsurface wave velocity, estimation of the depth of the point target, and the modified range and azimuth filters to achieve optimum resolution. The theoretical approach is described and results are presented for a range of point target depths, subsurface velocities, and radar system parameters. It is found that with the assumptions made it is possible to image the point targets in 3D with good range, azimuth, and depth accuracy.","Title: Mapping Canadian wetlands using L-band radar satellite imagery S\nYear: 2009\n\nAbstract: Previously, we have developed a robust algorithm for mapping boreal wetlands using L-band satellite radar imagery, and in particular have used the method to produce a complete vegetated wetlands map of Alaska using the JERS radar data. In this work, we apply this algorithm to produce a static map of Canadian wetlands from the 1997-98 era JERS radar data at 100-m resolution, to be followed in the future by 2007-era ALOS/PALSAR maps.","Title: Coherent Scattering of Electromagnetic Waves From Two-Layer Rough Surfaces Within the Kirchhoff Regime\nYear: 2013\n\nAbstract: We present an analytical solution for coherent scattering of electromagnetic waves from a two-layer rough surface structure with uncorrelated random rough interfaces. The Kirchhoff approximation is used to predict the coherent (specular) component of the scattered wave from a layered rough surface that is assumed to have radii of curvature much larger than the wavelength to allow the application of the method. The roughness on both boundaries is assumed small such that the coherent component of the scattered wave is dominant. The derived solution includes all orders of the scattered wave and has a simple algebraic expression that can be readily computed. We validate the solution against a numerical method and present simulation results for various cases.","Title: Design and Implementation of Low-Power and Mid-Range Magnetic-Induction-Based Wireless Underground Sensor Networks.\nYear: 2016\n\nAbstract: Low-power wireless communication in underground settings and confined areas is considered one of last frontiers in communications. First, there is the energy challenge: because the nodes are embedded in some kind of medium, such as soil, concrete, or debris of a disaster event, many of the traditional energy solutions for communication devices are ruled out. Second, typical radio-wave-based soluti...","Title: Generalized Terrain Topography in Radar Scattering Models.\nYear: 2016\n\nAbstract: Modeling of terrain topography is crucial for vegetated areas given that even small slopes impact and alter the radar wave interactions between the ground and the overlying vegetation. Current missions either exclude pixels with large topographic slopes or disregard the terrain topography entirely, potentially accumulating substantial modeling errors and therefore impacting the retrieval performan...","Title: Method For Upscaling In-Situ Soil Moisture Measurements For Calibration And Validation Of Smap Soil Moisture Products\nYear: 2016\n\nAbstract: In order to provide a reliable source of ground-based validation data for the SMAP mission at spatial scales of 3 km, 9 km and 36 km, we have developed a new regression-based method capable of yielding highly-accurate upscaled soil moisture estimates based on sparse, irregularly-spaced soil moisture measurements.","Title: Assessment Of Retrieval Errors Of Airmoss Root-Zone Soil Moisture Products\nYear: 2016\n\nAbstract: We have concluded that before calculation of the AirMOSS project overall RMSE, not only the behavior and location of in-situ soil moisture probes need to be carefully evaluated but also the present error biases—associated with the in-situ probes, radar calibration, vegetation parameterization, forward model inaccuracy, and the inversion algorithm bias—need to be removed. Several measures have been taken over the course of AirMOSS mission to increase the accuracy of RZSM products. The overall RMSE was reported for each study site. We can show that the overall AirMOSS retrieval error for the top 25 cm in BERMS, Metolius, MOISST, Tonzi Ranch, and Walnut Gulch meets the mission RMSE requirement. This error would be calculated in terms of RMSE between the retrieved and actual moisture values over all qualified validation points, all sites, and all dates. The retrieval performance is expected to improve even more with reprocessing of some of the flights using recalibrated radar data.","Title: Joint-Physics Emission-Scattering Model For Improved Active-Passive Soil Moisture Estimation\nYear: 2016\n\nAbstract: Improved soil moisture estimation, within a combined radar-radiometer framework, by using Joint-physics modeling is demonstrated and presented in this work. Detailed numerical simulation on bare, but rough surfaces, highlight how improved emission-scattering modeling, can outperform conventional approaches. Root-mean-squared error statistics show almost a factor of two improvement in soil permittivity predictions.","Title: The Importance Of Forest Spatial Heterogeneity: Exploring The Effect Of Mix Scenes Using Coherence Three-Dimension Radar Backscattering Model\nYear: 2016\n\nAbstract: Mix-scene of forest with the combination of different land cover types, such as grass, or crop, in one pixel is common, especially for the low resolution SAR images. Various radar models have been developed through years. However, the heterogeneous effect of mix-scene is not well understood quantitative so far, which might cause substantial uncertainty in the soil moisture and biomass estimations. We investigated this effect by using a coherence 3D vegetation radar model, which is firstly parametrized and validated using the ground measurements and airborne P band SAR data at pine forest of Metolius, Oregon, USA, 2013-2014. The airborne SAR data and simulated data are in good agreement with mean difference less than 1dB and correlation coefficient above 0.96. Secondly, Simulation of several mix-scenes of the same area, tree density and height but difference tree clumping patterns and mixed with different land cover types were performed. The largest difference can up to 3dB of extreme tree clumping patterns. This study demonstrates how important it is to consider the horizontal forest heterogeneity of mix-scene. Further study with quantitative description of horizontal heterogeneity of mix land cover and the effect to soil moisture and biomass estimation are needed.","Title: A Time-Series Active Layer Thickness Retrieval Algorithm Using P- And L-Band Sar Observations\nYear: 2016\n\nAbstract: In this paper, an active layer thickness (ALT) retrieval algorithm is presented wherein time-series of P- and L-band radar observations are used simultaneously to retrieve the depth from ground surface to permafrost table. Several model assumptions for two active layer soil conditions (maximum thaw and partially frozen) are made based on observations of in situ soil temperature and soil moisture data. It is expected that P- and L-band radar measurements can provide different aspects of active layer soil structure for retrieving accurate ALT. Monte Carlo numerical simulations are performed to show the potentials of the proposed inversion scheme and its capability of resolving subsurface features in a layered soil structure.","Title: Surface soil moisture retrieval using L-band SMAP SAR data and its validation\nYear: 2016\n\nAbstract: Surface soil moisture was retrieved globally by systematically correcting for the effects of vegetation and soil surface roughness. The retrieval is enabled by employing physical-models of radar forward scattering for individual vegetation types to account for vegetation scattering and absorption, and by constraining the surface roughness effect using time-series observations. The L-band SMAP multi-polarized (HH/VV/HV) σ° data acquired globally every three days were used from mid-April to early July, 2015. Assessment was conducted over 13 rigorously-chosen core validation sites covering a wide range of biomass types, biomass amount, and soil conditions. The soil moisture retrieval reached an accuracy of 0.06 m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n/m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n RMSE, a bias of 0.003 m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n/m\n<sup xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">3</sup>\n, and a correlation of 0.56. The successful retrieval demonstrates that the physically-based retrieval method is capable of characterizing soil moisture over diverse conditions of soil moisture, surface roughness, and vegetation on a global scale.","Title: Decomposing soil and vegetation contributions in polarimetric L- and P- band SAR observations.\nYear: 2016\n\nAbstract: Microwave-based retrieval of soil moisture in vegetated areas have uncertainties due the sensitivity of the signal to vegetation structure and dielectric constant. In this study, we propose a framework for developing a joint active L-band and active P-band retrieval algorithm to decrease the retrieval uncertainties. The algorithm focuses on the decomposition of soil, vegetation and dihedral components to compare the observations from the two frequencies.","Title: A Multi-Objective Optimization Approach To Combined Radar-Radiometer Soil Moisture Estimation\nYear: 2016\n\nAbstract: With emphasis on physics-based techniques, a multi-objective optimization approach to combined radar-radiometer soil moisture estimation is presented in this work. Soil moisture estimation is demonstrated via application of this method to SMAP high resolution radar and coarse resolution radiometer data. Comparisons are then made with the SMAP baseline active-passive soil moisture output data product. A strong agreement between the two techniques, especially in capturing spatial distributions of soil moisture is observed.","Title: Surface Soil Moisture Retrieval Using the L-Band Synthetic Aperture Radar Onboard the Soil Moisture Active-Passive Satellite and Evaluation at Core Validation Sites.\nYear: 2017\n\nAbstract: This paper evaluates the retrieval of soil moisture in the top 5-cm layer at 3-km spatial resolution using L-band dual-copolarized Soil Moisture Active-Passive (SMAP) synthetic aperture radar (SAR) data that mapped the globe every three days from mid-April to early July, 2015. Surface soil moisture retrievals using radar observations have been challenging in the past due to complicating factors of...","Title: Combined Radar-Radiometer Surface Soil Moisture and Roughness Estimation.\nYear: 2017\n\nAbstract: A robust physics-based combined active-passive (C-AP), or active-passive, surface soil moisture and roughness estimation methodology is presented. Soil moisture and roughness retrieval is performed via optimization, i.e., minimization, of a joint objective function, which constrains similar resolution radar and radiometer observations simultaneously. A data-driven and noise-dependent regularizatio...","Title: Advancing NASA's AirMOSS P-Band Radar Root Zone Soil Moisture Retrieval Algorithm via Incorporation of Richards' Equation.\nYear: 2017\n\nAbstract: P-band radar remote sensing applied during the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission has shown great potential for estimation of root zone soil moisture. When retrieving the soil moisture profile (SMP) from P-band radar observations, a mathematical function describing the vertical moisture distribution is required. Because only a limited number of observations are available, the number of free parameters of the mathematical model must not exceed the number of observed data. For this reason, an empirical quadratic function (second order polynomial) is currently applied in the AirMOSS inversion algorithm to retrieve the SMP. The three free parameters of the polynomial are retrieved for each AirMOSS pixel using three backscatter observations (i.e., one frequency at three polarizations of Horizontal-Horizontal, Vertical-Vertical and Horizontal-Vertical). In this paper, a more realistic, physically-based SMP model containing three free parameters is derived, based on a solution to Richards' equation for unsaturated flow in soils. Evaluation of the new SMP model based on both numerical simulations and measured data revealed that it exhibits greater flexibility for fitting measured and simulated SMPs than the currently applied polynomial. It is also demonstrated that the new SMP model can be reduced to a second order polynomial at the expense of fitting accuracy.","Title: Data Assimilation to Extract Soil Moisture Information from SMAP Observations.\nYear: 2017\n\nAbstract: This study compares different methods to extract soil moisture information through the assimilation of Soil Moisture Active Passive (SMAP) observations. Neural network (NN) and physically-based SMAP soil moisture retrievals were assimilated into the National Aeronautics and Space Administration (NASA) Catchment model over the contiguous United States for April 2015 to March 2017. By construction, the NN retrievals are consistent with the global climatology of the Catchment model soil moisture. Assimilating the NN retrievals without further bias correction improved the surface and root zone correlations against in situ measurements from 14 SMAP core validation sites (CVS) by 0.12 and 0.16, respectively, over the model-only skill, and reduced the surface and root zone unbiased root-mean-square error (ubRMSE) by 0.005 m respectively. The assimilation reduced the average absolute surface bias against the CVS measurements by 0.009 m. Assimilating the NN retrievals after a localized bias correction yielded slightly lower surface correlation and ubRMSE improvements, but generally the skill differences were small. The assimilation of the physically-based SMAP Level-2 passive soil moisture retrievals using a global bias correction yielded similar skill improvements, as did the direct assimilation of locally bias-corrected SMAP brightness temperatures within the SMAP Level-4 soil moisture algorithm. The results show that global bias correction methods may be able to extract more independent information from SMAP observations compared to local bias correction methods, but without accurate quality control and observation error characterization they are also more vulnerable to adverse effects from retrieval errors related to uncertainties in the retrieval inputs and algorithm. Furthermore, the results show that using global bias correction approaches without a simultaneous re-calibration of the land model processes can lead to skill degradation in other land surface variables.","Title: Real-Time Three-Dimensional Microwave Monitoring of Interstitial Thermal Therapy.\nYear: 2018\n\nAbstract: We report a method for real-time threedimensional monitoring of thermal therapy through the use of noncontact microwave imaging. This method is predicated on using microwaves to image changes in the dielectric properties of tissue with changing temperature. Instead of the precomputed linear Born approximation that was used in prior work to speed up the frame-to-frame inversions, here we use the no...","Title: Towards Multi-Frequency Soil Moisture Retrieval Using P- and L-Band Passive Microwave Sensing Technology.\nYear: 2018\n\nAbstract: A fundamental limitation of current soil moisture remote sensing technology is that can only provide moisture information on the top 5 cm layer of soil at most, being one-tenth to one-quarter of the wavelength (21 cm at L-band; 1.4 GHz) using the current SMAP and SMOS soil moisture dedicated missions of NASA and ESA. Consequently, we have developed an airborne passive microwave sensing capability at P-band to develop a new state-of-the-art satellite concept that will provide soil moisture data for the top 10 cm layer of soil using radiometer observations at P-band (40 cm; 750 MHz). Not only would P-band provide soil moisture information on a soil layer thickness that more closely relates to that affecting crop and pasture growth, but it is expected to produce greater spatial coverage with improved accuracy to that from L-band. This is because P-band should be less affected by surface roughness conditions and have a reduced attenuation by the overlaying vegetation. This paper describes a series of small airborne field experiments at P-band, and presents some early results of P-band passive microwave observations in comparison with L-band and K-band passive microwave from initial trial flights.","Title: A Method for Upscaling In Situ Soil Moisture Measurements to Satellite Footprint Scale Using Random Forests.\nYear: 2017\n\nAbstract: Geophysical products generated from remotely sensed data require validation to evaluate their accuracy. Typically in situ measurements are used for validation, as is the case for satellite-derived soil moisture products. However, a large disparity in scales often exists between in situ measurements (covering meters to 10 s of meters) and satellite footprints (often hundreds of meters to several ki...","Title: Spatial and Temporal Variability of Root-Zone Soil Moisture Acquired From Hydrologic Modeling and AirMOSS P-Band Radar.\nYear: 2018\n\nAbstract: The accurate estimation of grid-scale fluxes of water, energy, and carbon requires consideration of subgrid spatial variability in root-zone soil moisture (RZSM). The NASA Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission represents the first systematic attempt to repeatedly map high-resolution RZSM fields using airborne remote sensing across a range of biomes. Here, we ...","Title: 3-D Level Set Method for Joint Contrast and Shape Recovery in Microwave Imaging\nYear: 2019\n\nAbstract: We propose a three-dimensional (3-D) fast level set method, which can estimate both object shape and dielectric contrast with reduced computational cost. In prior work, we presented a 2-D fast level set method that integrated the level set inversion within the Born iterative method (BIM). This approach significantly reduced the computational cost; however, it was limited to estimating object shape without providing any dielectric contrast inversion. In this paper, we extend our previous method to 3-D and add the capability to estimate dielectric contrast in addition to the shape. The contrast estimation is formulated as a separate step within the BIM iteration, such that the shape and contrast are estimated sequentially in each BIM iteration. This modular framework enables the freedom to choose any arbitrary constraints on the contrast in the cost function. Here, we demonstrate the applicability of a total-variation constraint for the contrast cost function. To validate the method, synthetic data are generated for objects within a 3-D imaging cavity and are then used to test for robustness against variations in object shape, size, position, and contrast. Further, the method is tested on MRI-derived numerical breast phantoms. The reconstructed images indicate that the method can produce accurate estimates of object location, shape, and size while recovering the contrast with an error lower than \n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><tex-math notation=\"LaTeX\">$\\text{2}\\%$</tex-math></inline-formula>\n.","Title: Retrieval of Permafrost Active Layer Properties Using Time-Series P-Band Radar Observations\nYear: 2019\n\nAbstract: We propose a method to estimate the active layer properties, including soil dielectric profiles and active layer thickness (ALT), in permafrost regions using time-series P-band polarimetric synthetic aperture radar (SAR) observations. The active layer and underlying permafrost are modeled as a three-layer dielectric structure with the layer dielectric constants representing the soil moisture and freeze-thaw state of the layer. To resolve the ambiguity of the retrieved layer thicknesses, an approach of finding the largest possible depths (LPDs) is combined with time-series observations, where the ALT is assumed time-invariant between the maximum thaw and before the upward freezing front rises significantly from the permafrost table. The LPD-assisted time-series retrieval algorithm is applied to the radar data acquired by the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) P-band SAR in August and October 2014 and 2015 over the Alaska North Slope. The results show that the retrieved ALT values are generally underestimated for the sites where the \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">in situ</italic>\n ALT is larger than the P-band sensing depth, with a retrieval bias ranging from −0.05 to −0.24 m as validated against the \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">in situ</italic>\n ALT collected at Circumpolar Active Layer Monitoring (CALM) sites. For the sites where the \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">in situ</italic>\n ALT is smaller than 0.55 m, the retrieval errors are generally less than 0.1 m. The retrieval results also show that the active layer properties are strongly influenced by the land cover types at the regional scale, and not as much by the North–South temperature gradient across a 180-km-long transect along the Deadhorse flight line.","Title: Validation Of Permafrost Active Layer Estimates From Airborne Sar Observations\nYear: 2021\n\nAbstract: In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic and elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have emerged as a method for observing seasonal thaw subsidence, soil moisture, and ALT in permafrost regions. This study validates airborne SAR-derived ALT estimates in three regions of Alaska, USA using calibrated ground penetrating radar (GPR) geophysical data. The remotely sensed ALT estimates matched the field observations within uncertainty for 79% of locations. The average uncertainty for the GPR-derived ALT validation dataset was 0.14 m while the average uncertainty for the SAR-derived ALT in pixels coincident with GPR data was 0.19 m. In the region near Utqiavik, the remotely sensed ALT appeared slightly larger than field observations while in the Yukon-Kuskokwim Delta region, the remotely sensed ALT appeared slightly smaller than field observations. In the northern foothills of the Brooks Range, near Toolik Lake, there was minimal bias between the field data and remotely sensed estimates. These findings suggest that airborne SAR-derived ALT estimates compare well with in situ probing and GPR, making SAR an effective tool to monitor permafrost measurements.","Title: A Versatile and Shelf-Stable Dielectric Coupling Medium for Microwave Imaging\nYear: 2022\n\nAbstract: <italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Objective:</i>\n To develop a new class of emulsions using a protein-based emulsifier as the coupling fluid for microwave imaging systems. \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Methods:</i>\n In this paper, we provide a theoretical basis for engineering shelf-stable dielectric fluids, a step-by-step formulation method, and measurements of complex dielectric properties in the frequency range of 0.5-3 GHz, which can be applicable for many of the recent microwave imaging systems. \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Results:</i>\n This medium was primarily designed for long-term stability while providing a controllable range of complex dielectric permittivities given different fractions of its constituents. Consequently, this emulsion shows dielectric stability in open air throughout a 7-day experiment and temperature insensitivity over the range of 0\n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><tex-math notation=\"LaTeX\">${\\,^\\circ }$</tex-math></inline-formula>\nC to 60\n<inline-formula xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><tex-math notation=\"LaTeX\">${^\\circ }$</tex-math></inline-formula>\n. \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Conclusions:</i>\n This control over dielectric permittivity enables formulations that tune the background-to-target contrast to the linearizable regime of iterative inverse scattering algorithms. Accordingly, the emulsion conductivity can also be controlled and reduced to maintain the required signal-to-noise ratio within the dynamic range of the imaging system. The new formulation overcomes the practical challenges of engineering coupling fluids for microwave imaging systems, e.g., temporal stability, non-toxic, low sensitivity to temperature variation, and easy formulation from readily available and inexpensive materials. \n<italic xmlns:mml=\"http://www.w3.org/1998/Math/MathML\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">Significance:</i>\n The achieved properties associated with this new fluid are of particular benefit to microwave imaging systems used in thermal therapy monitoring.","Title: Embedded Temporal Convolutional Networks for Essential Climate Variables Forecasting\nYear: 2022\n\nAbstract: Forecasting the values of essential climate variables like land surface temperature and soil moisture can play a paramount role in understanding and predicting the impact of climate change. This work concerns the development of a deep learning model for analyzing and predicting spatial time series, considering both satellite derived and model-based data assimilation processes. To that end, we propose the Embedded Temporal Convolutional Network (E-TCN) architecture, which integrates three different networks, namely an encoder network, a temporal convolutional network, and a decoder network. The model accepts as input satellite or assimilation model derived values, such as land surface temperature and soil moisture, with monthly periodicity, going back more than fifteen years. We use our model and compare its results with the state-of-the-art model for spatiotemporal data, the ConvLSTM model. To quantify performance, we explore different cases of spatial resolution, spatial region extension, number of training examples and prediction windows, among others. The proposed approach achieves better performance in terms of prediction accuracy, while using a smaller number of parameters compared to the ConvLSTM model. Although we focus on two specific environmental variables, the method can be readily applied to other variables of interest.","Title: Sensitivity of Multifrequency Polarimetric SAR Data to Postfire Permafrost Changes and Recovery Processes in Arctic Tundra\nYear: 2022\n\nAbstract: We used full-polarimetric L-band and P-band synthetic aperture radar (SAR) data collected from the recent NASA Arctic Boreal Vulnerability Experiment (ABoVE) airborne campaign and Sentinel-1 C-band dual-polarization data to understand the sensitivity of radar backscatter intensity and phase to fire-induced changes in the surface and subsurface soil processes in Arctic tundra underlain by permafrost. The 2007 Anaktuvuk River fire on the Alaska North Slope was used as a case study. At similar to 10-year postfire, we observed a strong increase (>similar to 3-4 dB) in the low-frequency radar backscatter in severely burned areas during the thaw season, in contrast to limited (<similar to 0.5 dB) C-band backscatter differences (VV and VH) between burned and unburned areas. However, C-band winter backscatter is generally higher (>1 dB) in burned areas than the adjacent unburned areas. Polarimetric decomposition analysis indicated a general trend toward more random surface scattering, and strong increases in double-bounce scattering and volume scattering power at both P- and L-band in the burned areas. The ice-rich yedoma region shows the largest backscatter increases in burned areas and the highest correlation with burn severity and microtopography changes. The above backscatter changes are attributed to increasing surface roughness and microtopography due to ice-wedge degradation and thermokarst development and increasing subsurface scattering due to an overall drier and deeper active layer in burned areas. Among all frequencies, P-band shows consistently larger contrast in backscatter power and phase between burned and unburned areas, which makes it potentially more useful to study fire-permafrost interactions in the Arctic over decadal time scales.","Title: Wireless Sensor Network Informed UAV Path Planning for Soil Moisture Mapping\nYear: 2022\n\nAbstract: Adaptive and targeted allocation of mobile sensing agents, in the form of unmanned aerial vehicles (UAVs) with software defined radar (UAV-SDRadar) payloads, enable mapping of surface soil moisture in regions where in situ wireless sensor networks (WSNs) undersample soil moisture or upscaling models perform poorly. This work presents an optimization-based UAV path planning methodology that seeks to maximize UAV flight coverage over areas where a complementing WSN yields upscaled soil moisture estimates with high uncertainty. By recursively mapping soil moisture over such areas, the combined UAV and WSN instrumentation can gradually capture the domain's true mean soil moisture. A series of numerical simulations are presented to demonstrate the algorithm's basic function while considering real-world and feasible operational scenarios.","Title: Snow Depth Retrieval With an Autonomous UAV-Mounted Software-Defined Radar\nYear: 2022\n\nAbstract: We present results from a field campaign to measure seasonal snow depth at Cameron Pass, Colorado, using a synthetic ultrawideband software-defined radar (SDRadar) implemented in commercially available Universal Software Radio Peripheral (USRP) software-defined radio hardware and flown on a small hexacopter unmanned aerial vehicle (UAV). We coherently synthesize an ultrawideband signal from stepped frequency 50-MHz subpulses across 600-2100-MHz frequency bands using a novel nonuniform nonlinear synthetic wideband waveform reconstruction technique that minimizes sweep time and completely eliminates problematic grating lobes and other processing artifacts traditionally seen in stepped waveform synthesis. We image seasonal snow across two transects: a 400-m open Meadow Transect and a 380-m forested transect. We present a surface detection algorithm that fuses data from LiDAR, global navigation satellite system (GNSS)/global positioning system (GPS), and features in the radargram itself to obtain high precision estimates of both snow and ground surface reflections, and thus total snow depth, represented as two-way travel time. The measurements are validated against independent ground-based ground-penetrating radar measurements with correlations coefficients as high as rho = 0.9 demonstrated. Finally, we compare backscattered radar data collected by the UAV-SDRadar while hovering proximal to a known snow pit with in situ measured snow dielectric profiles and demonstrate imaging of snow stratigraphy.","Title: GNSS-R Soil Moisture Retrieval for Flat Vegetated Surfaces Using a Physics-Based Bistatic Scattering Model and Hybrid Global/Local Optimization\nYear: 2022\n\nAbstract: This paper presents a soil moisture retrieval scheme from Cyclone Global Navigation Satellite System (CYGNSS) delay-Doppler maps (DDMs) over land. The proposed inversion method consists of a hybrid global and local optimization method and a physics-based bistatic scattering forward model. The forward model was developed for bare-to-densely vegetated terrains, and it predicts the circularly polarized bistatic radar cross section DDM of the land surface. This method was tested on both simulated DDMs and CYGNSS DDMs over the Soil Moisture Active Passive (SMAP) Yanco core validation site in Australia. About 250 CYGNSS DDMs from 2019 and 2020 over the Yanco site were used for validation. The simulated DDMs were for grassland and forest vegetation types. The vegetation type of the Yanco validation site was grassland. The vegetation water content (VWC) was 0.19 kg m(-2) and 4.89 kg m(-2) for the grassland and forest terrains, respectively. For the case when the surface roughness is known to the algorithm, the unbiased root mean square error (ubRMSE) of soil moisture estimates was less than 0.03 m(3) m(-3) while it was approximately 0.06 m(3) m(-3) and 0.09 m(3) m(-3) for the validation results from 2019 and 2020, respectively. The retrieval algorithm generally had enhanced performance for smaller values of soil moisture. For the case when both the soil moisture and surface roughness are unknown to the algorithm and only a single DDM is used for retrieval, the validation results showed an expected reduced performance, with an an ubRMSE of less than 0.12 m(3) m(-)(3).","Title: Intercomparison of Electromagnetic Scattering Models for Delay-Doppler Maps Along a CYGNSS Land Track With Topography\nYear: 2022\n\nAbstract: A comparison of three different electromagnetic scattering models for land surface delay-Doppler maps (DDMs) obtained from global navigation satellite system reflectometry (GNSS-R) along a Cyclone Global Navigation Satellite System (CYGNSS) track in the San Luis Valley, Colorado, USA, is presented. The three models are the analytical Kirchhoff solutions (AKS), the Soil And VEgetation Reflection Simulator (SAVERS), and the improved geometrical optics with topography (IGOT). Common inputs to the three models were defined by using field samples of soil moisture and texture, soil surface roughness measurements, and a digital elevation model (DEM). The resulting peak reflectivity profiles of the models and the CYGNSS data all had a range of 10 dB along the selected track, mainly due to the influence of topography. The reflectivities obtained from all three models agreed with one another within 2.4 dB along the full length of the track. The models also showed general agreement with the corresponding CYGNSS data, although the modeled profiles were higher than CYGNSS Science Data Record Version 3.1 by an average of 5 dB and also smoother. Additional characterization of fine-scale surface roughness is identified as an area for future work to improve model fidelity. An intercomparison of DDM structure for three selected acquisitions is also provided."],"string":"[\n \"Title: Sensitivity Analysis of the Simulated Annealing Method to Measurement Noise for the Inversion of Subsurface Parameters of Two Layer Rough Surfaces\\nYear: 2008\\n\\nAbstract: where the quantities σo pq (X; fi ,θ j) and dpq (fi ,θ j) are, respectively, the calculated and measured backscattering coefficient of the layered structure at a certain frequency and observation angle for pq polarization. The backscattering coefficients σo vv and σo hh are available from our incoherent first order SPM forward model (3), which is also used to synthesize the measured data to develop and validate the inversion algorithm. The values of Nf and Nθ are, respectively, the number of frequency points and measurement angles used in the measurement. We use nine model parameters to characterize the two layer structure. These parameters are real parts of the layers permittivities (� 1r and � 2r), conductivities of the layers (σ1 and σ2), the standard deviation and correlation length of each interface (σfi and lfi), along with the mean separation between the two rough interfaces (d). The vector of unknowns, X, is defined such that X(1) = � 1r, X(2) = σ1, X(3) = � 2r, X(4) = σ2, X(5) = d, X(6) = lf1 , X(7) = σf1, X(8) = lf2, and X(9) = σf2 . We have shown that error in the a-priori values assigned to known model parameters would result in large errors in the solution. Therefore, we treat all the nine model parameters as unknown in this optimization problem.\",\n \"Title: Proposed investigations from NASA's Earth Venture-1 (EV-1) airborne science selections\\nYear: 2010\\n\\nAbstract: On 27 May 2010, NASA announced the first Earth Venture (EV-1) selections in response to a recommendation made by the National Research Council for low-cost investigations fostering innovation in Earth Science. The five EV-1 investigations span the Earth science focus areas of atmosphere, weather, climate, water and energy and, carbon and represent Earth science researchers from NASA as well as other government agencies, academia and industry from around the world. The five EV-1 missions are (1) Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS); (2) Airborne Tropical TRopopause Experiment (ATTREX); (3) Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE); (4) Deriving Information on Surface Conditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ), and (5) Hurricane and Severe Storm Sentinel (HS3). The Earth Venture missions are managed out of the Earth System Science Pathfinder (ESSP) Program Office [3]\",\n \"Title: Inversion of Subsurface Properties of Layered Dielectric Structures With Random Slightly Rough Interfaces Using the Method of Simulated Annealing\\nYear: 2009\\n\\nAbstract: In this paper, the model parameters of a two-layer dielectric structure with random slightly rough boundaries are retrieved from data that consist of the backscattering coefficients for multiple polarizations, angles, and frequencies. We use the small perturbation method to solve the forward problem. The inversion problem is then formulated as a least square problem and is solved using a global optimization method known as simulated annealing, which is shown to be a robust retrieval algorithm for our purpose. The algorithm performance depends on several parameters. We make recommendations on these parameters and propose a technique for exiting local minima when encountered. We test the sensitivity of the inversion scheme to measurement noise and present the noise analysis results.\",\n \"Title: Ripple-2: a non-collaborative; asynchronous; and open architecture for highly-scalable and low duty-cycle WSNs\\nYear: 2013\\n\\nAbstract: The design of Ripple-2, a wireless in-situ soil moisture sensing system is presented in this paper. The main objective of such system is to collect high fidelity and fine grained data both spatially and temporally compared to radar remote sensing, which is the more traditional way of capturing soil moisture, and to use the former to validate and calibrate the latter. To do so, the in-site sensor network must cover a sufficiently large area, on the order of at least a few square kilometers. At the same time, cost constraints (both in deployment and in maintenance) puts a limit on the total number of sensor nodes, resulting in a very sparse (on average) network. The main challenge in designing the system lies in achieving reliability and energy efficiency in such a sparse network. For instance, in our pilot deployment, a 200mx400m area is covered by 22 nodes (average inter-node distance > 50m). Traditional WSN technology typically calls for many more nodes to be deployed in such an area. Ripple-2 is introduced as a non-traditional WSN architecture where (1) the network is physically and logically segmented into isolated clusters, (2) a regular node (or end device, ED) only communicates with the cluster head (CH) of its segment, and (3) the ED-CH communication is distinct from the CH-sink (or CH-Data Server) and both links can use virtually any kind of point-to-point wireless technology. We use both simulated and empirical results to demonstrate the effectiveness of Ripple-2; it proves to be ideal for low duty-cycle data collection applications due to its exceptional small network overhead (typically smaller than 1%) and its robustness to the size of the network.\",\n \"Title: WSN-SA: Design foundations for situational awareness systems based on sensor networks.\\nYear: 2013\\n\\nAbstract: WSN-SA is a Wireless Sensor Networks (WSN) framework that is been proposed to support rescue operations in collapsed structures, such as houses and buildings, after natural and human-made disasters. The sensors and actuators are deployed prior to the disaster and ideally such sensor network is a required infrastructure of any building. Such SA systems can help to indicate how to distribute the rescue resources and how to identify imminent risks for rescuers and survivors. So far, few situational awareness (SA) systems based on WSNs have been proposed and no long-term realization of such systems has been reported. The goal of this work is to provide the foundations to change this reality so it would be possible to see a SA system accompanying each existing fire system. To this end, a strong emphasis is given to a) the achievement of low total cost of ownership (TCO), b) reliability, c) and expandability for the adopted SA solution.\",\n \"Title: Investigating spatial aggregation techniques using a heterogeneous radar landscape simulator for reducing uncertainties of soil moisture retrieval from SMAP.\\nYear: 2011\\n\\nAbstract: In this paper, a heterogeneous landscape simulator is introduced, which will facilitate lifelike forward modeling of various landscapes by taking additional information and ancillary data into account. First results of simple spatial aggregation techniques are discussed and the uncertainty of soil moisture retrieval is quantified. A scaling analysis is performed by investigating above- and below-ground modeling parameters for their influence on the radar model output and their impact on simple aggregation problems.\",\n \"Title: Radar Retrieval of Surface and Deep Soil Moisture and Effect of Moisture Profile on Inversion Accuracy.\\nYear: 2011\\n\\nAbstract: We study the retrieval of surface and deep moisture of bare soil from noisy radar observations using simulated annealing. Due to moisture variations with depth, we model bare soil with a stratified dielectric profile with a rough surface on top. Small perturbation method (SPM) is used as the forward model. We use the full moisture profile for radar data synthesis and study the retrieval accuracy b...\",\n \"Title: Microwave breast imaging system prototype with integrated numerical characterization.\\nYear: 2012\\n\\nAbstract: The increasing number of experimental microwave breast imaging systems and the need to properly model them have motivated our development of an integrated numerical characterization technique. We use Ansoft HFSS and a formalism we developed previously to numerically characterize an S-parameter- based breast imaging system and link it to an inverse scattering algorithm. We show successful reconstructions of simple test objects using synthetic and experimental data. We demonstrate the sensitivity of image reconstructions to knowledge of the background dielectric properties and show the limits of the current model.\",\n \"Title: Microwave Observatory of Subcanopy and Subsurface (MOSS): A Mission Concept for Global Deep Soil Moisture Observations\\nYear: 2007\\n\\nAbstract: The Microwave Observatory of Subcanopy and Subsurface (MOSS) is a mission concept for a spaceborne synthetic aperture radar (SAR) system that provides global observations of soil moisture under substantial vegetation cover (exceeding 20 kg/m2 ) and at useful depths (1-5 m). The concept was developed and a number of new required technologies were demonstrated through a National Aeronautics and Space Administration Earth Science Technology Office Instrument Incubator Program project. This very high frequency (VHF)/ultrahigh frequency (UHF) polarimetric SAR is designed to provide 7-10-day observations of soil moisture at 1-km resolution. The rapid repeat cycle mandates swath widths in the range of 300-400 km, which must be realized by a 30-m-long antenna. Conventional array implementations would result in a mass of more than 4000 kg, whereas with the technology proposed and demonstrated in this project, the total antenna mass is less than 500 kg. The antenna concept is a dual-stacked patch array feed illuminating a 30-m mesh reflector to synthesize the long apertures and achieve the wide swath. The feed system prototype was fabricated and its performance demonstrated. Other major project components were: (1) system-level SAR and mission design; (2) demonstration of science data and products, using a tower-based VHF/UHF radar; (3) spacecraft and mesh reflector antenna mechanical design; (4) developing mitigation strategies for ionospheric effects; and (5) assessing frequency interference effects. Experimental science data were generated from the tower radar for soil moisture profiling in Arizona and for forest penetration in Oregon. The soil moisture products were demonstrated through an integrated inversion-processing algorithm. This paper summarizes the results from the MOSS project and demonstrates the feasibility of the spaceborne mission.\",\n \"Title: Electromagnetic Scattering From Mutilayer Rough Surfaces Separated By Arbitrary Dielectric Profiles\\nYear: 2006\\n\\nAbstract: Radar remote sensing of soil moisture content at low frequencies requires an accurate scattering model of realistic soils, which often involves multilayer rough surfaces and inhomogeneous dielectric profiles. In this paper, a hybrid analytical/numerical solution to two-dimensional scattering from multilayer rough surfaces separated by arbitrary dielectric profiles based on the extended boundary condition method (EBCM) and scattering matrix technique is presented. The reflection and transmission matrices of a rough interface are constructed using EBCM. The inhomogeneous dielectric profile is modeled as a stack of piecewise homogeneous dielectric thin layers. The scattering matrices of an inhomogeneous dielectric profile are computed by recursively cascading reflection and transmission matrices of individual dielectric interfaces from the bottom dielectric interface to the top interface. The interactions between the rough interfaces and the inhomogeneous dielectric profile are taken into account by applying the generalized scattering matrix technique. In numerical simulations, the actual field-collected soil moisture data are used. In particular, the dielectric profiles during both dry and wet ground conditions are examined. The numerical Simulations are performed to investigate both bistatic scattering coefficients and copolarized phase difference due to different subsurface roughness parameters and ground conditions. Simulation results show that the bistatic scattering coefficients air, low frequencies are sensitive to Subsurface roughness parameters and copolarized phase difference strongly depends on soil moisture contents.\",\n \"Title: An Adaptive Energy-Management Framework For Sensor Nodes With Constrained Energy Scavenging Profiles\\nYear: 2013\\n\\nAbstract: Modern energy harvesting systems for WSNs involve power scavenging sources, rechargeable batteries, and supercapacitors. Typical energy-management systems calculate/predict the remaining energy stored in a node, and associated actions are dispatched involving the networking protocols. However, long-term characteristics of the mentioned hardware components are typically neglected preventing the achievement of very long maintenance-free lifetimes (e.g., > 5 years) for the nodes. In this work, a systematic analysis of this problem is provided, and an open energy-management framework is proposed which promotes (a) the nontraditional combination of primary cells, supercapacitors, and harvesting systems, (b) the concept of a distributed system inside a node, and (c) the adoption of the dual duty-cycle (DDC) operation for the WSNs. The DDC's core component is a cross-layer protocol implemented as an application-layer overlay which maintains the operation of the network under very high energy efficiency. Its trade-off is the reduction of the network throughput. Therefore, the DDC system has mechanisms that dynamically switch the WSN operational mode according to application's needs. Detailed guidelines are provided in order to allow the implementation of the solution on existing WSN platforms. The energy efficiency of the low duty-cycle mode of the solution is demonstrated by simulated and empirical results.\",\n \"Title: Power-Management Techniques For Wireless Sensor Networks And Similar Low-Power Communication Devices Based On Nonrechargeable Batteries\\nYear: 2012\\n\\nAbstract: Despite the well-known advantages of communication solutions based on energy harvesting, there are scenarios where the absence of batteries (supercapacitor only) or the use of rechargeable batteries is not a realistic option. Therefore, the alternative is to extend as much as possible the lifetime of primary cells (nonrechargeable batteries). By assuming low duty-cycle applications, three power-management techniques are combined in a novel way to provide an efficient energy solution for wireless sensor networks nodes or similar communication devices powered by primary cells. Accordingly, a customized node is designed and long-term experiments in laboratory and outdoors are realized. Simulated and empirical results show that the battery lifetime can be drastically enhanced. However, two trade-offs are identified: a significant increase of both data latency and hardware/software complexity. Unattended nodes deployed in outdoors under extreme temperatures, buried sensors (underground communication), and nodes embedded in the structure of buildings, bridges, and roads are some of the target scenarios for this work. Part of the provided guidelines can be used to extend the battery lifetime of communication devices in general.\",\n \"Title: Backscattering Simulation For Nonuniform Forest Canopies Using Multi-Layer Mimics\\nYear: 2004\\n\\nAbstract: In this paper, we introduce a multi-layer MIMICS for nonuniform forest canopies and present the model applications. The Michigan Microwave Canopy Scattering model (MIMICS) has been developed to simulate microwave backscattering from tree canopies. However, the crown-trunk canopy model is too restrictive for nonuniform canopy coverage. Multilayer MIMICS is developed to remove the two-layer canopy restriction. The model is a simulation solution to an array of radiative transfer equations and it includes the layer interactions between overlapping layers. This paper is focused on the model validation and application of multi-layer MIMICS. Our collaborators have supplied us with extensive ground truth data from a 220,000 ha woodland and forest study areas within central Queensland, Australia. The field measurement is at the individual tree level. We can simulate the polarimetric backscattering for the ground measurement. AIRSAR data of the same area are obtained to validate the model simulation. The results show good agreement between the model simulation and SAR measurements. Analyzing an individual layer's contribution offers better understanding of canopy composition effects on backscattering. The multi-layer canopy configuration improves the estimate accuracy over that from a crown-trunk layer model, as in the older version of MIMICS.\",\n \"Title: A Simulation Study Of Compact Polarimetry For Radar Retrieval Of Soil Moisture\\nYear: 2014\\n\\nAbstract: A compact polarimetric (CP) radar system requires fewer measurements than a fully polarimetric (FP) system, thus allowing added flexibility in radar system design. Previous studies have shown the potential of using compact polarimetry for radar remote sensing of soil moisture. This paper extends previous studies by considering a time series data cube retrieval algorithm and measurements in the presence of vegetation. Vegetation information is assumed to be provided by an ancillary data source in the retrieval process. The performance of an algorithm for reconstructing FP information from CP measurements of vegetated soil surfaces is also examined. The results of the study show that only a modest degradation in soil moisture retrieval performance occurs when compact-pol measurements are used in place of full-pol data.\",\n \"Title: Two-dimensional full-wave scattering from discrete random media in layered rough surfaces\\nYear: 2007\\n\\nAbstract: Modeling of electromagnetic scattering from discrete random media in layered rough surfaces finds various applications, including depth retrieval of layered snow-covered ice and remote sensing of vegetation canopy. In this paper, a coherent technique for solving scattering from discrete random media in layered rough surfaces is presented. The significance of the development of a full-wave solution to this problem stems from the fact that both co-polarized phase difference and polarized scattering coefficients can only be accurately determined using a coherent approach. Therefore, the objective of this paper is to formulate a full-wave solution for scattering from discrete random media in layered rough surfaces as well as to demonstrate the potential in the retrieval of subsurface parameters pertaining to the physical properties of rough surfaces and discrete random media using polarized scattering coefficients and co- polarized phase difference. The core of our technique lies in the use of plane wave decomposition. Plane wave solution for the scattered field due to a rough surface is obtained using extended boundary condition method (EBCM). The recursive T-matrix algorithm together with cylindrical-waves-to-plane-waves transformation matrices is employed to deal with scattering from discrete random media. Subsequently, plane wave solutions for the scattered fields due to rough surfaces and discrete random media are then cast into reflection and transmission matrices. These reflection and transmission matrices facilitate the application of scattering matrix technique which coherently accounts for electromagnetic interactions between layered rough surfaces and discrete random media. Various numerical results are examined and it is shown that the subsurface parameters may significantly impact backscattering coefficients and co-polarized phase difference even when the subsurface ground is covered by a rough layer of discrete random media.\",\n \"Title: Deriving soil moisture with the combined L-band radar and radiometer measurements\\nYear: 2010\\n\\nAbstract: In this study, we develop a combined active/passive technique to estimate surface soil moisture with the focus on the short vegetated surfaces. We first simulated a database for both active and passive signals under SMAP's sensor configurations using the radiative transfer model with a wide range of conditions for surface soil moisture, roughness and vegetation properties that we considered as the random orientated disks and cylinders. Using this database, we developed 1) the techniques to estimate surface backscattering and emission components and 2) the technique to estimate soil moisture with the estimated surface backscattering and emission components. We will demonstrate these techniques with the model simulated data and its validation with the airborne PALS image data from the soil moisture SGP'99 and SMEX'02 experiments.\",\n \"Title: Radiative transfer model for microwave bistatic scattering from forest canopies\\nYear: 2005\\n\\nAbstract: A bistatic forest scattering model is developed to simulate scattering coefficients from forest canopies. The model is based on the Michigan Microwave Canopy Scattering (MIMICS) model (hence called Bi-MIMICS) and uses radiative transfer theory, where the first-order fully polarimetric transformation matrix is used. Bistatic radar systems offer advantages over monostatic radar systems because of the additional information provided by the diversity of the geometry. By simulating the forest canopy scattering from multiple viewpoints, we can better understand how the forest scatterers' shape, orientation, density, and permittivity affect the canopy scattering. Bi-MIMICS is parametrized using selected forest stands with different canopy compositions and structure. The simulation results show that bistatic scattering is more sensitive to forest biomass changes than backscattering. Analyzing scattering contributions from different parts of the canopy gives us a better understanding of the microwave's interaction with the tree components. The ground effects can also be studied. Knowledge of the canopy's bistatic scattering behavior combined with additional synthetic aperture radar measurements can be used to improve forest parameter retrievals. The simulation results of the model provide the required information for the design of future bistatic radar systems for forest sensing applications.\",\n \"Title: Electromagnetic scattering from arbitrary random rough surfaces using stabilized extended boundary condition method (SEBCM) for remote sensing of soil moisture\\nYear: 2010\\n\\nAbstract: In this paper, the stabilized extended boundary condition method (SEBCM) is developed based on the classical EBCM to solve both 2D and 3D electromagnetic scattering from arbitrary random rough surfaces. The SEBCM gives accurate full wave solutions over large range of surface roughnesses and medium losses, which are far beyond the validity range of analytical methods, and perform with much higher efficiency than numerical methods. These properties make SEBCM a competitive forward model in the inverse problem for soil moisture retrieval from radar measurements.\",\n \"Title: Large-Domain, Low-Contrast Acoustic Inverse Scattering For Ultrasound Breast Imaging\\nYear: 2010\\n\\nAbstract: We present a full-wave acoustic inverse-scattering algorithm designed specifically for ultrasonic breast imaging. At ultrasonic frequencies, the image domain is roughly tens to hundreds of lambda(min) cubed, where lambda(min) is the smallest wavelength in the transmit signal spectrum. The expected range of contrasts for the breast imaging problem for density, compressibility, and compressive loss is +/- 20% of the background. Because of the low contrast, Born iterations provide the basic structure of the inverse-scattering algorithm. However, we use a multiobjective covariance-based least squares cost function in place of the basic least squares cost function to estimate the contrast functions. This cost function provides physically meaningful regularization based on a priori knowledge of the contrasts. Also, due to the size of the imaging domain and because the objects to be imaged are low contrast and inhomogeneous, we use the Neumann series solution as the forward solver. The largest domain imaged in simulation was 50 lambda(min) X 50 lambda(min) in 2-D.\",\n \"Title: Guest EditorialSpecial Section on the 2007 International Conference on Near-Field Imaging and Characterization (ICONIC'07)\\nYear: 2008\\n\\nAbstract: The four papers in this special section present a sparse but diverse sampling of some of the prominent near-field imaging techniques for very different applications.\",\n \"Title: ADvances in radar forward and inverse scattering models of subsurface and subcanopy soil moisture and their role for the AirMOSS mission\\nYear: 2012\\n\\nAbstract: The Airborne Observatory of Subcanopy and Subsurface (AirMOSS) is one of the five Earth Venture-1 missions selected in May 2010, and seeks to improve the estimates of the north American net ecosystem carbon exchange (NEE) through high-resolution observations of root zone soil moisture (RZSM). To obtain estimates of RZSM and assess its heterogeneities, AirMOSS will fly a P-band (430 MHz) synthetic aperture radar (SAR) over 2500 km2 areas within nine major biomes of north America. Retrieval of RZSM in the presence of substantial vegetation requires the construction of accurate radar scattering models that account for diverse vegetation conditions as well as subsurface inhomogeneities. In this paper we provide a summary of recent advances in this area, emphasizing several coherent and incoherent models of scattering from multilayered inhomogeneous rough surfaces, as well as strategies for using these forward models in retrieval algorithms.\",\n \"Title: Electromagnetic scattering from multilayer rough surfaces based on extended boundary condition formulation and transition matrix approach\\nYear: 2005\\n\\nAbstract: The electromagnetic scattering of rough surface has been investigated extensively for the past decades. There exist analytical solutions to rough surface scattering such as small perturbation method (SPM) or Kirchhoff approximation (KA). These analytical solutions, however, are limited to either small or large roughness regimes. Recent efforts have been put forth to study scattering from multilayer rough surface in the application of deep soil moisture estimation. In this paper, multilayer rough surface scattering is analyzed based on an approach which combines extended boundary condition formulation (EBC) and transition matrix method. From the Floquet theorem, the Floquet modes translate into the coherent reflection and transmission coefficients in their corresponding scattering directions. To account for coherent multiple interactions between rough surface layers, transition matrix approach is used. Each Floquet mode direction is considered a port of a multiport system and network theory is used to characterize cascaded rough surface layers. Bistatic scattering coefficients are then obtained by incoherently averaging the power computed from the resultant Floquet modes in the scattering directions. Therefore, the electromagnetic wave interactions in multilayer rough surfaces are analyzed in a very efficient way by applying EBC to each rough surface and then cascading iteratively transition matrix of each layer interface. Finally, the results are validated against the analytical SPM solution to two-layer rough surface scattering.\",\n \"Title: Radar backscattering model for multilayer mixed-species forests\\nYear: 2005\\n\\nAbstract: A multilayer canopy scattering model is developed for mixed-species forests. The multilayer model provides a significantly enhanced representation of actual complex forest structures compared to the conventional canopy-trunk layer models. Multilayer Michigan Microwave Canopy Scattering model (Multi-MIMICS) allows overlapping layer configuration and a tapered trunk model applicable to forests of mixed species and/or mixed growth stages. The model is the first-order solution to a set of radiative transfer equations and includes layer interactions between overlapping layers. It simulates SAR backscattering coefficients based on input dimensional, geometrical, and dielectric variables of forest canopies. The Multi-MIMICS is an efficient realization of actual forest structures and can be shaped for specific interest of forest parameters. We present the model's application and validation in the paper. The model is parameterized using data collected from a 220,000-ha area of forests in central Queensland, Australia. Fifteen 50×50 m test sites representing the general forest diversity and growth stages are chosen as ground truth. Polarimetric backscattering airborne SAR (AIRSAR) data of the same area are acquired to validate the model simulations. The model predicts SAR backscattering coefficients of the test areas. Simulation results show a good agreement with AIRSAR data at most frequencies and polarizations. The simulated backscattering coefficient from the multilayer model and the standard MIMICS are also compared and significant improvements are observed.\",\n \"Title: Electromagnetic scattering from multilayer rough surfaces with arbitrary dielectric profiles for remote sensing of subsurface soil moisture\\nYear: 2007\\n\\nAbstract: Radar remote sensing of soil moisture content at low frequencies requires an accurate scattering model of realistic soils, which often involves multilayer rough surfaces and inhomogeneous dielectric profiles. In this paper, a hybrid analytical/numerical solution to two- dimensional scattering from multilayer rough surfaces separated by arbitrary dielectric profiles based on the extended boundary condition method (EBCM) and scattering matrix technique is presented. The reflection and transmission matrices of a rough interface are constructed using EBCM. The inhomogeneous dielectric profile is modeled as a stack of piecewise homogeneous dielectric thin layers. The scattering matrices of an inhomogeneous dielectric profile are computed by recursively cascading reflection and transmission matrices of individual dielectric interfaces. The interactions between the rough interfaces and the inhomogeneous dielectric profile are accounted for by applying the generalized scattering matrix technique. The solution presented in this paper is for the two-dimensional scenario of multilayer rough surfaces. The technique can also be applied in three dimensions. In numerical simulations, the actual field-collected soil moisture data are used. In particular, the dielectric profiles during both dry and wet ground conditions are examined. The numerical simulations are performed to investigate both backscattering scattering coefficients and co- polarized phase difference due to different subsurface roughness parameters and ground conditions. The results show that both backscattering coefficients and co-polarized phase difference at low frequencies are sensitive to the roughness of subsurface interfaces and deep soil moisture. Also, much larger depth sensitivity can be achieved using co-polarized phase difference than scattering coefficients.\",\n \"Title: Models of L-Band Radar Backscattering Coefficients Over Global Terrain for Soil Moisture Retrieval\\nYear: 2014\\n\\nAbstract: Physical models for radar backscattering coefficients are developed for the global land surface at L-band (1.26 GHz) and 40 ° incidence angle to apply to the soil moisture retrieval from the upcoming soil moisture active passive mission data. The simulation of land surface classes includes 12 vegetation types defined by the International Geosphere-Biosphere Programme scheme, and four major crops (wheat, corn, rice, and soybean). Backscattering coefficients for four polarizations (HH/VV/HV/350611873VH) are produced. In the physical models, three terms are considered within the framework of distorted Born approximation: surface scattering, double-bounce volume-surface interaction, and volume scattering. Numerical solutions of Maxwell equations as well as theoretical models are used for surface scattering, double-bounce reflectivity, and volume scattering of a single scatterer. To facilitate fast, real-time, and accurate inversion of soil moisture, the outputs of physical model are provided as lookup tables (with three axes; therefore called datacube). The three axes are the real part of the dielectric constant of soil, soil surface root mean square (RMS) height, and vegetation water content (VWC), each of, which covers the wide range of natural conditions. Datacubes for most of the classes are simulated using input parameters from in situ and airborne observations. This simulation results are found accurate to the co-pol RMS errors of to 3.4 dB (six woody vegetation types), 1.8 dB (grass), and 2.9 dB (corn) when compared with airborne data. Validated with independent spaceborne phased array type L-band synthetic aperture radars and field-based radar data, the datacube errors for the co-pols are within 3.4 dB (woody savanna and shrub) and 1.5 dB (bare surface). Assessed with spaceborne Aquarius scatterometer data, the mean differences range from ~ 1.5 to 2 dB. The datacubes allow direct inversion of sophisticated forward models without empirical par- meters or formulae. This capability is evaluated using the time-series inversion algorithm over grass fields.\",\n \"Title: Potential of L-Band Radar for Retrieval of Canopy and Subcanopy Parameters of Boreal Forests.\\nYear: 2012\\n\\nAbstract: In this paper, we study the radar retrieval of soil moisture as well as canopy parameters in a range of boreal forests. The retrieval is formulated as an optimization problem where the difference between data and prediction of a forward scattering model is minimized. The forward model is a discrete scatterer radar model, and the optimization algorithm is a global optimization scheme known as simul...\",\n \"Title: Estimation of crown and stem water content and biomass of boreal forest using polarimetric SAR imagery\\nYear: 2000\\n\\nAbstract: Characterization of boreal forests in ecosystem models requires temporal and spatial distributions of water content and biomass over local and regional scales. The authors report on the use of a semi-empirical algorithm for deriving these parameters from polarimetric synthetic aperture radar (SAR) measurements. The algorithm is based on a two layer radar backscatter model that stratifies the forest canopy into crown and stem layers and separates the structural and biometric attributes of forest stands. The structural parameters are estimated by training the model with SAR image data over dominant coniferous and deciduous stands in the boreal forest such as jack pine, black spruce, and aspen. The algorithm is then applied on AIRSAR images collected during the Boreal Ecosystem Atmospheric Study (BOREAS) over the boreal forest of Canada. The results are verified using biometry measurements during BOREAS-intensive field campaigns. Field data relating the water content of tree components to dry biomass are used to modify the coefficients of the algorithm for crown and stem biomass. The algorithm was then applied over the entire image generating biomass maps. A set of 18 test sites within the imaged area was used to assess the accuracy of the biomass maps. The accuracy of biomass estimation is also investigated by choosing different combinations of polarization and frequency channels of the AIRSAR system. It is shown that polarimetric data from P-band and L-band channels provide similar accuracy for estimating the above-ground biomass for boreal forest types. In general, the use of P-band channels can provide better estimates of stem biomass, while L-band channels can estimate the crown biomass more accurately\",\n \"Title: Bistatic Vector 3-D Scattering From Layered Rough Surfaces Using Stabilized Extended Boundary Condition Method.\\nYear: 2013\\n\\nAbstract: A model of 3-D electromagnetic scattering from multiple rough surfaces within homogeneous-layered or vertically inhomogeneous media is developed in this work. This model, aimed at radar remote sensing of surface-to-depth profiles of soil moisture, computes total bistatic radar cross sections from the multilayer structure based on the scattering matrix approach, cascading the scattering matrices of...\",\n \"Title: 3-D Vector Electromagnetic Scattering From Arbitrary Random Rough Surfaces Using Stabilized Extended Boundary Condition Method for Remote Sensing of Soil Moisture\\nYear: 2012\\n\\nAbstract: We develop the stabilized extended boundary condition method (SEBCM) based on the classical EBCM to solve the 3-D vector electromagnetic scattering problem from arbitrary random rough surfaces. Similar to the classical EBCM, we expand the fields in terms of Floquet modes and match the extended boundary conditions at test surfaces away from the actual rough surface to retrieve the surface currents and therefore the scattered fields. However, to solve long-standing stability problems of the classical EBCM, we introduce a z-coordinate transformation to restrict and control the test surface locations explicitly. We also introduce the concepts of moderated test surface locations and balanced k-charts for further stabilization and optimization of the solutions. The computational efficiency is optimized by judicious submatrix decomposition. The resulting bistatic scattering cross sections are validated by comparing with analytical and numerical solutions. Specifically, the solutions are compared with those from the small perturbation method and small-slope approximation within their validity region, and with those from the method of moments outside the validity domains of analytical solutions. It is shown that SEBCM gives accurate, numerically efficient, full-wave solutions over a large range of surface roughnesses and medium losses, which are far beyond the validity range of analytical methods. These properties are expected to make SEBCM a competitive forward solver for soil moisture retrieval from radar measurements.\",\n \"Title: Analysis of scattering mechanisms in SAR imagery over boreal forest: results from BOREAS '93\\nYear: 1995\\n\\nAbstract: As part of the intensive field campaign (IFC) for the Boreal forest ecosystem-atmosphere research (BOREAS) project in August 1993, the NASA/JPL AIRSAR covered an area of about 100 km×100 km near the Prince Albert National Park in Saskatchewan, Canada. At the same time, ground-truth measurements were made in several stands which have been selected as the primary study sites. This paper focuses on an area including jack pine stands in the Nipawin area near the park. Upon examining the AIRSAR data from stands of old and young jack pine (OJP and YJP), distinct signatures are observed for each of the forest types at various frequencies and polarizations, in particular, at P-band HH. The authors use a forest scattering model in conjunction with the ground-truth measurements to explain such behavior. The forest model includes the major scattering mechanisms by taking the forest component interactions into account. The contribution from each of the scattering mechanisms to the total backscatter is calculated and their differences for OJP and YJP stands are evaluated. The results are used to discuss the effect of the physical properties of the forest components in each stand on radar backscatter. They are also used to show that it is not only the backscatter level but also the relative contribution from various scattering mechanisms that will help in quantitative interpretation of SAR data. This work is mainly intended as a precursor to the authors ongoing work which uses a mechanism-specific inversion technique to retrieve forest parameters from SAR data for these BOREAS sites\",\n \"Title: Inversion Of A Layered Rough Surface Model: Maximizing The Number Of Retrievable Parameters For The Design Of Future Subsurface Sensing Radar Systems\\nYear: 2007\\n\\nAbstract: We previously applied an optimization technique known as Simulated Annealing (SA) to the inverse problem associated with a 31) two-layer dielectric structure with slightly rough interfaces and showed that simulated annealing methods are capable of globally minimizing cost functions with many local minima [1]. Nonlinearity of the cost function is a major factor that decreases the performance of the inversion algorithm. With a fixed set of measurement and inversion parameters, as the number of unknown model parameters increases, the cost function nonlinearity becomes more severe, decreasing the efficiency of inversion and making the annealing process perform like an inefficient brute force search. The focus of this work is on strategies to choose the optimal set of measurement parameters for retrieval of the largest possible number of parameters of a layered dielectric structure.\",\n \"Title: Study of Validity Region of Small Perturbation Method for Two-Layer Rough Surfaces\\nYear: 2010\\n\\nAbstract: We previously derived the bistatic scattering coefficients of a 3-D two-layer dielectric structure with slightly rough boundaries using the small perturbation method (SPM). The use of SPM raises the question about its region of validity, which pertains to the conditions on each layer roughness, slope, and permittivity for which the first-order SPM is accurate within a specified error bound. To thi...\",\n \"Title: A Wireless Soil Moisture Smart Sensor Web Using Physics-Based Optimal Control: Concept and Initial Demonstrations\\nYear: 2010\\n\\nAbstract: This paper introduces a new concept for a smart wireless sensor web technology for optimal measurements of surface-to-depth profiles of soil moisture using in-situ sensors. The objective of the technology, supported by the NASA Earth Science Technology Office Advanced Information Systems Technology program, is to enable a guided and adaptive sampling strategy for the in-situ sensor network to meet the measurement validation objectives of spaceborne soil moisture sensors. A potential application for this technology is the validation of products from the Soil Moisture Active/Passive (SMAP) mission. Spatially, the total variability in soil-moisture fields comes from variability in processes on various scales. Temporally, variability is caused by external forcings, landscape heterogeneity, and antecedent conditions. Installing a dense in-situ network to sample the field continuously in time for all ranges of variability is impractical. However, a sparser but smarter network with an optimized measurement schedule can provide the validation estimates by operating in a guided fashion with guidance from its own sparse measurements. The feedback and control take place in the context of a dynamic physics-based hydrologic and sensor modeling system. The overall design of the smart sensor web-including the control architecture, physics-based hydrologic and sensor models, and actuation and communication hardware-is presented in this paper. We also present results illustrating sensor scheduling and estimation strategies as well as initial numerical and field demonstrations of the sensor web concept. It is shown that the coordinated operation of sensors through the control policy results in substantial savings in resource usage.\",\n \"Title: Classification of Alaska Spring Thaw Characteristics Using Satellite L-Band Radar Remote Sensing\\nYear: 2015\\n\\nAbstract: Spatial and temporal variability in landscape freeze- thaw (FT) status at higher latitudes and elevations significantly impacts land surface water mobility and surface energy partitioning, with major consequences for regional climate, hydrological, ecological, and biogeochemical processes. With the development of new-generation spaceborne remote sensing instruments, future L-band missions, including the NASA Soil Moisture Active and Passive mission, will provide new operational retrievals of landscape FT state dynamics at moderate (~3 km) spatial resolution. We applied theoretical simulations of L-band radar backscatter using first-order radiative transfer models with two and three-layer modeling schemes to develop a modified seasonal threshold algorithm (STA) and FT classification study over Alaska using 100-m-resolution satellite Phased Array L-band Synthetic Aperture Radar (PALSAR) observations. The backscatter threshold distinguishes between frozen and nonfrozen states, and it is used to classify the predominant frozen or thawed status of a grid cell. An Alaska FT map for April 2007 was generated from PALSAR (ScanSAR) observations and showed a regionally consistent but finer FT spatial pattern than an alternative surface air temperature-based classification derived from global reanalysis data. Validation of the STA-based FT classification against regional soil climate stations indicated approximately 80% and 75% spatial classification accuracy values in relation to respective station air temperature and soil temperature measurement-based FT estimates. An investigation of relative spatial scale effects on FT classification accuracy indicates that the relationship between grid cell size and classified frozen or thawed area follows a general logarithmic function.\",\n \"Title: A Combined Active–Passive Soil Moisture Estimation Algorithm With Adaptive Regularization in Support of SMAP\\nYear: 2015\\n\\nAbstract: We present a method to combine same-resolution measurements of active radar and passive radiometer microwave remote sensing to build a framework for soil moisture estimation in support of the Soil Moisture Active and Passive (SMAP) mission. A unified active-passive soil moisture estimation algorithm is developed within a global optimization scheme, using a joint cost function with adaptive regularization, where, unlike traditional methods, both radar and radiometer measurements are utilized at the same time to retrieve soil moisture. Monte Carlo numerical simulations and optimization to retrieve soil moisture are performed for Corn, Soybean, and Grass landcover types for active-only, passive-only, and active-passive scenarios. These numerical experiments show that the proposed combined active-passive (CAP) soil moisture estimation approach outperforms either the single-sensor technique, particularly for higher vegetation water content (VWC) values (VWC > 3 kg/m2). For example, for the case of Corn with VWC of 5 kg/m2, retrieval error is reduced to 0.035 cm3/cm3 for the active-passive method from 0.08 cm3/cm3 for active scenarios. Furthermore, tests of this new algorithm on the Passive and Active Land S-band Sensor (PALS) Soil Moisture Experiment 2002 (SMEX02), as well as the Combined RadarRadiometer (ComRad) collocated active and passive data, demonstrate the applicability of this method to actual data, even with potentially inaccurate forward models and noisy data. Results indicate that the best soil moisture estimates over a large range of soil moisture (0.04-0.4 cm3/cm3) and vegetation (0-5 kg/m2) conditions are achievable when the adaptive regularization parameter γ is chosen to give slightly more weight to the radiometer forward model without discarding the complementary radar measurement points.\",\n \"Title: P-Band Radar Retrieval of Subsurface Soil Moisture Profile as a Second-Order Polynomial: First AirMOSS Results\\nYear: 2015\\n\\nAbstract: We propose a new model for estimating subsurface soil moisture using P-band radar data over barren, shrubland, and vegetated terrains. The unknown soil moisture profile is assumed to have a second-order polynomial form as a function of subsurface depth with three unknown coefficients that we estimate using the simulated annealing algorithm. These retrieved coefficients produce the value of soil moisture at any given depth up to a prescribed depth of validity. We use a discrete scattering model to calculate the radar backscattering coefficients of the terrain. The retrieval method is tested and developed with synthetic radar data and is validated with measured radar data and in situ soil moisture measurements. Both forward and inverse models are briefly explained. The radar data used in this paper have been collected during the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission flights in September and October of 2012 over a 100 km by 25 km area in Arizona, including the Walnut Gulch Experimental Watershed. The study area and the ancillary data layers used to characterize each radar pixel are explained. The inversion results are presented, and it is shown that the RMSE between the retrieved and measured soil moisture profiles ranges from 0.060 to 0.099 m3/m3, with a Root Mean Squared Error (RMSE) of 0.075 m3/m3 over all sites and all acquisition dates. We show that the accuracy of retrievals decreases as depth increases. The profiles used in validation are from a fairy dry season in Walnut Gulch and so are the accuracy conclusions.\",\n \"Title: The Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12): Prelaunch Calibration and Validation of the SMAP Soil Moisture Algorithms\\nYear: 2015\\n\\nAbstract: The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite is scheduled for launch in January 2015. In order to develop robust soil moisture retrieval algorithms that fully exploit the unique capabilities of SMAP, algorithm developers had identified a need for long-duration combined active and passive L-band microwave observations. In response to this need, a joint Canada-U.S. field experiment (SMAPVEX12) was conducted in Manitoba (Canada) over a six-week period in 2012. Several times per week, NASA flew two aircraft carrying instruments that could simulate the observations the SMAP satellite would provide. Ground crews collected soil moisture data, crop measurements, and biomass samples in support of this campaign. The objective of SMAPVEX12 was to support the development, enhancement, and testing of SMAP soil moisture retrieval algorithms. This paper details the airborne and field data collection as well as data calibration and analysis. Early results from the SMAP active radar retrieval methods are presented and demonstrate that relative and absolute soil moisture can be delivered by this approach. Passive active L-band sensor (PALS) antenna temperatures and reflectivity, as well as backscatter, closely follow dry down and wetting events observed during SMAPVEX12. The SMAPVEX12 experiment was highly successful in achieving its objectives and provides a unique and valuable data set that will advance algorithm development.\",\n \"Title: Generalized radar scattering model including terrain topography\\nYear: 2014\\n\\nAbstract: Terrain topography is of great importance for vegetated areas given that even small slopes impact and alter the radar wave interactions between the ground and the overlying vegetation. Current missions generally exclude pixels with large topographic slopes or disregard the terrain topography entirely, potentially accumulating substantial modeling errors and therefore impacting the retrieval performance over such sloped pixels. A flexible and modular radar scattering model has been developed: it describes multispecies vegetation over an N-layered soil with rough interfaces and considers a two-dimensional slope. Simulation results show the impact of a two-dimensional slope for a range of tilt angles: a 3 degree tilt in the plane of incidence translates to a change of up to 6 dB in HH, 2 dB in VV and 1 dB in HV for the total radar backscatter. The terrain topography is shown to be crucial for accurate forward modeling, especially over forested areas.\",\n \"Title: Mitigation of Faraday rotation effect for long-wavelength synthetic spaceborne radar data\\nYear: 2014\\n\\nAbstract: The focus for geophysical parameter retrieval from space, such as soil moisture, is shifting towards lower frequencies allowing better penetration through vegetation (rendering it less visible) and into the soil (allowing soil moisture sensing into depth). But the ionosphere becomes increasingly opaque at lower frequencies, which intensifies the need for mitigation of ionospheric effects to allow the use of spaceborne radar signals. This work focuses on a radar-only method to predict and mitigate the Faraday rotation effect, which is considered to be the remaining dominant effect. A novel method to retrieve the Faraday rotation angle by using three different optimization techniques in the presence of other system distortion terms with no external targets is presented. The retrieval performance with synthetic spaceborne radar data is very promising; it allows a successful retrieval of the Faraday rotation angle if it is initiated within ±25° of the ground truth.\",\n \"Title: Radar-radiometer soil moisture estimation with joint physics and adaptive regularization in support of SMAP\\nYear: 2014\\n\\nAbstract: A combined radar-radiometer soil moisture estimation framework is presented in this work, which utilizes both radar backscatter and radiometer brightness temperature using physics-based models that fundamentally couple the scattering and emission processes. A regularization or tuning parameter is introduced within the optimization algorithm to enable flexibility and adaptability. It is observed that by finding the right balance between radar and radiometer contributions within a “joint” cost function, best estimates over a larger range of surface soil moisture and roughness are achievable. Monte Carlo numerical simulations are performed to highlight how this novel Active-Passive method is capable of fully utilizing emission and scattering sensitivities to surface soil moisture.\",\n \"Title: The Effect of Variable Soil Moisture Profiles on P-Band Backscatter\\nYear: 2014\\n\\nAbstract: Radar measurements at P-band are sensitive to profile soil moisture. Associated backscatter measurements depend on the distribution and variation of the soil moisture profile. Existing scattering models account for this variation by approximating the soil moisture profile as consisting of a number of homogeneous layers. Since the inversion of the scattering models during the retrieval process can be based on only a few polarimetric backscatter measurements, the number of obtainable independent layers in the profile representation is limited. The purpose of this paper is to gain insights into the effects of the layering representation on the resulting modeled forward scattering. These insights form the rational basis for the design of retrieval algorithms. The effects of reflections between layers and other sources of error on simulated backscattering coefficients are first illustrated using several case studies. To determine the combined effect of different error sources for realistic soil moisture profiles, ten years of conditions at a grassland in California are studied. Depending on the layering strategy and the polarization, the root-mean-square error (RMSE) of backscattering coefficients due to misrepresenting the profile alone can be up to 2 dB, although errors can be up to 10 dB in particular cases. The error generally decreases as additional layers are added. The HH-polarization is more sensitive to the subsurface than the VV-polarization and has greater errors. Using a profile-dependent layer placement strategy decreases the RMSE of the backscatter simulation by less than 1 dB relative to a strategy with fixed layering.\",\n \"Title: On the Accuracy of Averaging Radar Backscattering Coefficients for Bare Soils Using the Finite-Element Method\\nYear: 2014\\n\\nAbstract: Radar backscattering coefficients for heterogeneous pixels are traditionally assumed to be the average of the coefficients for the constitutive homogeneous pixels. We investigate the validity of this assumption for bare rough surfaces by using the 2-D finite-element method to compute the ensemble averaged “true” coefficients for heterogeneous pixels and compare these values with the computed averages for a variety of surfaces. We quantify the impact of heterogeneity in both soil moisture and surface roughness on the averaging assumption. We find that the validity of the assumption rests crucially on the surface correlation type (exponential or Gaussian) and length. In particular, when considering pixels with either heterogeneous soil moisture or roughness, we find that for high-contrast pixels, the backscatter averaging assumption breaks down by as much as 11 dB for Gaussian correlated surfaces for the longest correlation lengths considered (regardless of the source of heterogeneity), whereas for exponentially correlated surfaces, it breaks down by 6 dB for pixels with heterogeneous roughness and 2 dB for pixels with heterogeneous moisture. We attribute this behavior to Gaussian correlated surfaces possessing higher cross-pixel coherent interactions. Furthermore, conditions of validity for the backscatter averaging assumption are identified.\",\n \"Title: Real-time Microwave Imaging of Differential Temperature for Thermal Therapy Monitoring\\nYear: 2014\\n\\nAbstract: A microwave imaging system for real-time 3-D imaging of differential temperature has been developed for the monitoring and feedback of thermal therapy systems. Design parameters are constrained by features of a prototype-focused microwave thermal therapy system for the breast, operating at 915 MHz. Real-time imaging is accomplished with a precomputed linear inverse scattering solution combined with continuous vector network analyzer (VNA) measurements of a 36-antenna, HFSS-modeled, cylindrical cavity. Volumetric images of differential change of dielectric constant due to temperature are formed with a refresh rate as fast as 1 frame/s and 1 (°)C resolution. Procedures for data segmentation and postprocessed S-parameter error-correction are developed. Antenna pair VNA calibration is accelerated by using the cavity as the unknown thru standard. The device is tested on water targets and a simple breast phantom. Differentially heated targets are successfully imaged in cluttered environments. The rate of change of scattering contrast magnitude correlates 1:1 with target temperature.\",\n \"Title: An integrated active-passive soil moisture retrieval algorithm for SMAP for bare surfaces\\nYear: 2012\\n\\nAbstract: An integrated soil moisture retrieval algorithm is presented in this work wherein both radar and radiometer measurements are used simultaneously to retrieve surface soil moisture. This method is applied to bare rough surfaces with varying soil moisture and roughness distributions. A thresholding method based on physical models of scattering and emission is presented to obtain equivalent estimated brightness temperatures from active radar measurements. This technique is used as a constraint to link active and passive data within the optimization scheme. Numerical simulations are performed to investigate the proposed inversion technique using the method of Simulated Annealing.\",\n \"Title: The effects of noise on model inversion for the retrieval of forest structure from SAR data\\nYear: 2012\\n\\nAbstract: The inversion of physics based models presents an alternative to empirical relationships for the retrieval of forest structure from Synthetic Aperture Radar (SAR) data. A major disadvantage of such techniques is instability in the presence of moderate levels of noise. The effects of noise on the accuracy with which parameters can be retrieved is evaluated in this study under a number of conditions.\",\n \"Title: A generalized radar scattering model for multispecies forests with multilayer subsurface soil\\nYear: 2012\\n\\nAbstract: A generalized radar scattering model to predict backscattering for different frequencies and polarizations is crucial in the endeavor to understand the relationship between radar measurement and properties of both the vegetation and soil, and for allowing the estimation of both vegetation and soil information from radar data. In this work, we develop a combined radar scattering model of vegetation and multilayered soil structure to represent realistic soils with multiple layers of various textures, depths, and moisture contents. A multilayered soil scattering model based on first order small perturbation method (SPM) is integrated [1] to account for direct ground scattering. Furthermore, the coherent interaction between the vegetation and layered ground is included using a recently developed model based on the Kirchhoff approximation [2].\",\n \"Title: Backscattering of electromagnetic waves from layered rough surfaces and its application in estimating deep soil moisture\\nYear: 2004\\n\\nAbstract: An analytical method to calculate the scattering coefficients of a three-layer 3D rough surface is introduced. The two rough interfaces are assumed to be distinct. The waves in each region are represented as a superposition of an infinite number of up- and down-going spectral wave components, whose amplitudes are found by applying the boundary conditions. A small-perturbation formulation is used in the process and the scattering coefficients are derived to the first order. The formulation is validated against known solutions for special cases of flat interfaces as well as the single rough surfaces. Results are then generated for several cases of the three-layer rough interface medium, to be used for modeling of the backscattered signals from a tower-based radar system and subsequent estimation of multilayered soil properties such as moisture content and subsurface layer height\",\n \"Title: The MOSS VHF/UHF spaceborne SAR system testbed\\nYear: 2005\\n\\nAbstract: Summary form only given. This paper details our recent development of a system prototype for a spaceborne sensor that addresses the current NASA science priority of measuring soil moisture \\\"under a substantial vegetation canopy and reaching a useful depth within the uppermost soil layer\\\". The mission is named MOSS, for the Microwave Observatory of Subcanopy and Subsurface. It will enable measurement and derivation of data products not obtained from any other current, planned, or proposed instrument, with a solution that offers high science value through a low-mass and, in the long-term, low-cost approach. The proposed system is a spaceborne synthetic aperture radar (SAR) operating at the two low frequencies of 435 MHz (UHF, P-band) and 137 MHz (VHF) to enable sensing through vegetation and down into soil. The future mission scenario is achieved from a Sun synchronous orbit of 1313 km altitude, with a swath width of 430 km, incidence angle ranges of 17-30 degrees, resolution of 1 km, and a 7-day exact repeat consistent with the temporal scale of variations of the subcanopy and subsurface soil moisture. We describe a tower-based test-bed that we have developed to validate the spaceborne measurement concept. The processing software, including polarimetric calibration aspects, is detailed, and example science products are presented. The procedures and algorithms to estimate subsurface moisture are presented in detail, and the use an iterative estimation procedure is explained. The results are validated by comparing against detailed ground truth.\",\n \"Title: A Generalized Radar Backscattering Model Based on Wave Theory for Multilayer Multispecies Vegetation\\nYear: 2011\\n\\nAbstract: A generalized radar scattering model based on wave theory is described. The model predicts polarimetric radar backscattering coefficients for structurally complex vegetation comprised of multiple species and layers. Compared to conventional two-layer crown-trunk models, modeling of actual forests has been improved substantially, allowing better understanding of microwave interaction with vegetation. The model generalizes an existing single-species discrete scatterer model and, by including scattering and propagation effects through judiciously defined vegetation layers, enables its application to an arbitrary number of species types. The scatterers within each layer are modeled as finite cylinders or disks having arbitrary size, density, and orientation, as in the predecessor model. The distorted Born approximation is used to represent the propagation through each layer, while scattering from each is modeled as a linear superposition of scattering from its respective random collection of scatterers. Interactions of waves within and between each layer and direct scattering from the ground are accounted for. Validation of the model is presented based on its application to 23 wooded savanna sites located in Queensland, Australia, and comparison with Advanced Land Observing Satellite (ALOS) Phased Arrayed L-band Synthetic Aperture Radar (PALSAR) and National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) Airborne Synthetic Aperture Radar (AIRSAR) data. Results indicate good agreement between simulated and actual backscattering coefficients, particularly at HH and VV polarizations. More discrepancies are found at HV polarizations and can be explained by uncertainties in the knowledge of input parameters, such as inaccuracies in the surface model, surface roughness parameterization, and soil moisture.\",\n \"Title: A Preclinical System Prototype for Focused Microwave Thermal Therapy of the Breast\\nYear: 2012\\n\\nAbstract: A preclinical prototype of a transcutaneous thermal therapy system has been developed for the targeted treatment of breast cancer cells using focused microwaves as an adjuvant to radiation, chemotherapy, and high-intensity-focused ultrasound. The prototype system employs a 2-D array of tapered microstrip patch antennas operating at 915 MHz to focus continuous-wave microwave energy transcutaneously into the pendent breast suspended in a coupling medium. Prior imaging studies are used to ascertain the material properties of the breast tissue, and these data are incorporated into a multiphysics model. Time-reversal techniques are employed to find a solution (relative amplitudes and phase) for focusing at a given location. Modeling tests of this time-reversal focusing method have been performed, which demonstrate good targeting accuracy within heterogeneous breast tissue. Experimental results using the laboratory prototype to perform focused heating in tissue-mimicking gelatin phantoms have demonstrated 1.5-cm-diameter focal spot sizes and differential heating at the desired focus sufficient to achieve an antitumor effect confined to the target region.\",\n \"Title: Comparison of Gaussian and Rayleigh noise models in inversion of subsurface parameters of layered rough surfaces using simulated annealing\\nYear: 2009\\n\\nAbstract: This work addresses the noise sensitivity of the simulated annealing method in inversion of subsurface parameters of layered rough surfaces to measurement noise. We consider two different noise models and assess the noise response of the inversion algorithm for each of the models. Conclusions are made based on the calculated average and standard deviation of the output error in the retrieved model parameters.\",\n \"Title: Measurement Scheduling for Soil Moisture Sensing: From Physical Models to Optimal Control\\nYear: 2010\\n\\nAbstract: In this paper, we consider the problem of monitoring soil moisture evolution using a wireless network of in situ sensors. Continuously sampling moisture levels with these sensors incurs high-maintenance and energy consumption costs, which are particularly undesirable for wireless networks. Our main hypothesis is that a sparser set of measurements can meet the monitoring objectives in an energy-efficient manner. The underlying idea is that we can trade off some inaccuracy in estimating soil moisture evolution for a significant reduction in energy consumption. We investigate how to dynamically schedule the sensor measurements so as to balance this tradeoff. Unlike many prior studies on sensor scheduling that make generic assumptions on the statistics of the observed phenomenon, we obtain statistics of soil moisture evolution from a physical model. We formulate the optimal measurement scheduling and estimation problem as a partially observable Markov decision problem (POMDP). We then utilize special features of the problem to approximate the POMDP by a computationally simpler finite-state Markov decision problem (MDP). The result is a scalable, implementable technology that we have tested and validated numerically and in the field.\",\n \"Title: Radar retrieval of subsurface parameters for layered media with nonsmooth interfaces\\nYear: 2010\\n\\nAbstract: The solution to the inverse problem for a three-layer medium representing a large class of natural subsurface structures is developed in this paper using radar data. The retrieval of the layered medium parameters is accomplished as a sequential nonlinear optimization starting from the top layer and progressively characterizing the layers below. The optimization process is accomplished by an efficient iterative technique built around the solution of the forward scattering problem. The forward scattering process is formulated by using the Extended Boundary Condition Method (EBCM) and constructing reflection and transmission matrices for each interface. These matrices are then combined into the generalized scattering matrix for the entire system, from which radar scattering coefficients are then computed. To be efficiently utilized in the inverse problem, the forward scattering model is simulated over a wide range of unknowns to obtain a complete set of subspace-based equivalent closed form models that relate radar cross section coefficients to the sought-for parameters including dielectric constants of each layer and separation of the layers. The inversion algorithm is implemented as a modified conjugate-gradient-based nonlinear optimization. It is assumed that multifrequency radar measurements are available from tower-mounted or airborne platforms, for example at typical radar frequencies of L-band and P-band (UHF). It is shown that this technique results in accurate retrieval of surface and subsurface parameters, even in the presence of noise.\",\n \"Title: A radar-radiometer surface soil moisture retrieval algorithm for SMAP\\nYear: 2013\\n\\nAbstract: A soil moisture retrieval algorithm is presented whereby both radar and radiometer measurements are used simultaneously in an optimization scheme to retrieve for surface soil moisture in the presence of vegetation. Further, using fine-resolution radar measurements, a disaggregated brightness temperature product at the radar resolution is developed to reconcile the spatial resolution discrepancy between the two measurements. Numerical simulations are performed to synthesize SMAP data, and then via the method of Simulated Annealing, optimization is accomplished to retrieve high resolution soil moisture.\",\n \"Title: 3D SAR focusing for subsurface point targets\\nYear: 2009\\n\\nAbstract: In this work we develop a methodology for imaging subsurface point targets using a single-pass strip-map synthetic aperture radar (SAR). The point targets are embedded in an arbitrary homogeneous half space, and are located at arbitrary depths. It is assumed that the radar frequency is low enough and system sensitivity high enough to allow the required two-way penetration depth to target. The succession of steps required to form the image of the subsurface point targets are described, including the estimation of the subsurface wave velocity, estimation of the depth of the point target, and the modified range and azimuth filters to achieve optimum resolution. The theoretical approach is described and results are presented for a range of point target depths, subsurface velocities, and radar system parameters. It is found that with the assumptions made it is possible to image the point targets in 3D with good range, azimuth, and depth accuracy.\",\n \"Title: Mapping Canadian wetlands using L-band radar satellite imagery S\\nYear: 2009\\n\\nAbstract: Previously, we have developed a robust algorithm for mapping boreal wetlands using L-band satellite radar imagery, and in particular have used the method to produce a complete vegetated wetlands map of Alaska using the JERS radar data. In this work, we apply this algorithm to produce a static map of Canadian wetlands from the 1997-98 era JERS radar data at 100-m resolution, to be followed in the future by 2007-era ALOS/PALSAR maps.\",\n \"Title: Coherent Scattering of Electromagnetic Waves From Two-Layer Rough Surfaces Within the Kirchhoff Regime\\nYear: 2013\\n\\nAbstract: We present an analytical solution for coherent scattering of electromagnetic waves from a two-layer rough surface structure with uncorrelated random rough interfaces. The Kirchhoff approximation is used to predict the coherent (specular) component of the scattered wave from a layered rough surface that is assumed to have radii of curvature much larger than the wavelength to allow the application of the method. The roughness on both boundaries is assumed small such that the coherent component of the scattered wave is dominant. The derived solution includes all orders of the scattered wave and has a simple algebraic expression that can be readily computed. We validate the solution against a numerical method and present simulation results for various cases.\",\n \"Title: Design and Implementation of Low-Power and Mid-Range Magnetic-Induction-Based Wireless Underground Sensor Networks.\\nYear: 2016\\n\\nAbstract: Low-power wireless communication in underground settings and confined areas is considered one of last frontiers in communications. First, there is the energy challenge: because the nodes are embedded in some kind of medium, such as soil, concrete, or debris of a disaster event, many of the traditional energy solutions for communication devices are ruled out. Second, typical radio-wave-based soluti...\",\n \"Title: Generalized Terrain Topography in Radar Scattering Models.\\nYear: 2016\\n\\nAbstract: Modeling of terrain topography is crucial for vegetated areas given that even small slopes impact and alter the radar wave interactions between the ground and the overlying vegetation. Current missions either exclude pixels with large topographic slopes or disregard the terrain topography entirely, potentially accumulating substantial modeling errors and therefore impacting the retrieval performan...\",\n \"Title: Method For Upscaling In-Situ Soil Moisture Measurements For Calibration And Validation Of Smap Soil Moisture Products\\nYear: 2016\\n\\nAbstract: In order to provide a reliable source of ground-based validation data for the SMAP mission at spatial scales of 3 km, 9 km and 36 km, we have developed a new regression-based method capable of yielding highly-accurate upscaled soil moisture estimates based on sparse, irregularly-spaced soil moisture measurements.\",\n \"Title: Assessment Of Retrieval Errors Of Airmoss Root-Zone Soil Moisture Products\\nYear: 2016\\n\\nAbstract: We have concluded that before calculation of the AirMOSS project overall RMSE, not only the behavior and location of in-situ soil moisture probes need to be carefully evaluated but also the present error biases—associated with the in-situ probes, radar calibration, vegetation parameterization, forward model inaccuracy, and the inversion algorithm bias—need to be removed. Several measures have been taken over the course of AirMOSS mission to increase the accuracy of RZSM products. The overall RMSE was reported for each study site. We can show that the overall AirMOSS retrieval error for the top 25 cm in BERMS, Metolius, MOISST, Tonzi Ranch, and Walnut Gulch meets the mission RMSE requirement. This error would be calculated in terms of RMSE between the retrieved and actual moisture values over all qualified validation points, all sites, and all dates. The retrieval performance is expected to improve even more with reprocessing of some of the flights using recalibrated radar data.\",\n \"Title: Joint-Physics Emission-Scattering Model For Improved Active-Passive Soil Moisture Estimation\\nYear: 2016\\n\\nAbstract: Improved soil moisture estimation, within a combined radar-radiometer framework, by using Joint-physics modeling is demonstrated and presented in this work. Detailed numerical simulation on bare, but rough surfaces, highlight how improved emission-scattering modeling, can outperform conventional approaches. Root-mean-squared error statistics show almost a factor of two improvement in soil permittivity predictions.\",\n \"Title: The Importance Of Forest Spatial Heterogeneity: Exploring The Effect Of Mix Scenes Using Coherence Three-Dimension Radar Backscattering Model\\nYear: 2016\\n\\nAbstract: Mix-scene of forest with the combination of different land cover types, such as grass, or crop, in one pixel is common, especially for the low resolution SAR images. Various radar models have been developed through years. However, the heterogeneous effect of mix-scene is not well understood quantitative so far, which might cause substantial uncertainty in the soil moisture and biomass estimations. We investigated this effect by using a coherence 3D vegetation radar model, which is firstly parametrized and validated using the ground measurements and airborne P band SAR data at pine forest of Metolius, Oregon, USA, 2013-2014. The airborne SAR data and simulated data are in good agreement with mean difference less than 1dB and correlation coefficient above 0.96. Secondly, Simulation of several mix-scenes of the same area, tree density and height but difference tree clumping patterns and mixed with different land cover types were performed. The largest difference can up to 3dB of extreme tree clumping patterns. This study demonstrates how important it is to consider the horizontal forest heterogeneity of mix-scene. Further study with quantitative description of horizontal heterogeneity of mix land cover and the effect to soil moisture and biomass estimation are needed.\",\n \"Title: A Time-Series Active Layer Thickness Retrieval Algorithm Using P- And L-Band Sar Observations\\nYear: 2016\\n\\nAbstract: In this paper, an active layer thickness (ALT) retrieval algorithm is presented wherein time-series of P- and L-band radar observations are used simultaneously to retrieve the depth from ground surface to permafrost table. Several model assumptions for two active layer soil conditions (maximum thaw and partially frozen) are made based on observations of in situ soil temperature and soil moisture data. It is expected that P- and L-band radar measurements can provide different aspects of active layer soil structure for retrieving accurate ALT. Monte Carlo numerical simulations are performed to show the potentials of the proposed inversion scheme and its capability of resolving subsurface features in a layered soil structure.\",\n \"Title: Surface soil moisture retrieval using L-band SMAP SAR data and its validation\\nYear: 2016\\n\\nAbstract: Surface soil moisture was retrieved globally by systematically correcting for the effects of vegetation and soil surface roughness. The retrieval is enabled by employing physical-models of radar forward scattering for individual vegetation types to account for vegetation scattering and absorption, and by constraining the surface roughness effect using time-series observations. The L-band SMAP multi-polarized (HH/VV/HV) σ° data acquired globally every three days were used from mid-April to early July, 2015. Assessment was conducted over 13 rigorously-chosen core validation sites covering a wide range of biomass types, biomass amount, and soil conditions. The soil moisture retrieval reached an accuracy of 0.06 m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n/m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n RMSE, a bias of 0.003 m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n/m\\n<sup xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">3</sup>\\n, and a correlation of 0.56. The successful retrieval demonstrates that the physically-based retrieval method is capable of characterizing soil moisture over diverse conditions of soil moisture, surface roughness, and vegetation on a global scale.\",\n \"Title: Decomposing soil and vegetation contributions in polarimetric L- and P- band SAR observations.\\nYear: 2016\\n\\nAbstract: Microwave-based retrieval of soil moisture in vegetated areas have uncertainties due the sensitivity of the signal to vegetation structure and dielectric constant. In this study, we propose a framework for developing a joint active L-band and active P-band retrieval algorithm to decrease the retrieval uncertainties. The algorithm focuses on the decomposition of soil, vegetation and dihedral components to compare the observations from the two frequencies.\",\n \"Title: A Multi-Objective Optimization Approach To Combined Radar-Radiometer Soil Moisture Estimation\\nYear: 2016\\n\\nAbstract: With emphasis on physics-based techniques, a multi-objective optimization approach to combined radar-radiometer soil moisture estimation is presented in this work. Soil moisture estimation is demonstrated via application of this method to SMAP high resolution radar and coarse resolution radiometer data. Comparisons are then made with the SMAP baseline active-passive soil moisture output data product. A strong agreement between the two techniques, especially in capturing spatial distributions of soil moisture is observed.\",\n \"Title: Surface Soil Moisture Retrieval Using the L-Band Synthetic Aperture Radar Onboard the Soil Moisture Active-Passive Satellite and Evaluation at Core Validation Sites.\\nYear: 2017\\n\\nAbstract: This paper evaluates the retrieval of soil moisture in the top 5-cm layer at 3-km spatial resolution using L-band dual-copolarized Soil Moisture Active-Passive (SMAP) synthetic aperture radar (SAR) data that mapped the globe every three days from mid-April to early July, 2015. Surface soil moisture retrievals using radar observations have been challenging in the past due to complicating factors of...\",\n \"Title: Combined Radar-Radiometer Surface Soil Moisture and Roughness Estimation.\\nYear: 2017\\n\\nAbstract: A robust physics-based combined active-passive (C-AP), or active-passive, surface soil moisture and roughness estimation methodology is presented. Soil moisture and roughness retrieval is performed via optimization, i.e., minimization, of a joint objective function, which constrains similar resolution radar and radiometer observations simultaneously. A data-driven and noise-dependent regularizatio...\",\n \"Title: Advancing NASA's AirMOSS P-Band Radar Root Zone Soil Moisture Retrieval Algorithm via Incorporation of Richards' Equation.\\nYear: 2017\\n\\nAbstract: P-band radar remote sensing applied during the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission has shown great potential for estimation of root zone soil moisture. When retrieving the soil moisture profile (SMP) from P-band radar observations, a mathematical function describing the vertical moisture distribution is required. Because only a limited number of observations are available, the number of free parameters of the mathematical model must not exceed the number of observed data. For this reason, an empirical quadratic function (second order polynomial) is currently applied in the AirMOSS inversion algorithm to retrieve the SMP. The three free parameters of the polynomial are retrieved for each AirMOSS pixel using three backscatter observations (i.e., one frequency at three polarizations of Horizontal-Horizontal, Vertical-Vertical and Horizontal-Vertical). In this paper, a more realistic, physically-based SMP model containing three free parameters is derived, based on a solution to Richards' equation for unsaturated flow in soils. Evaluation of the new SMP model based on both numerical simulations and measured data revealed that it exhibits greater flexibility for fitting measured and simulated SMPs than the currently applied polynomial. It is also demonstrated that the new SMP model can be reduced to a second order polynomial at the expense of fitting accuracy.\",\n \"Title: Data Assimilation to Extract Soil Moisture Information from SMAP Observations.\\nYear: 2017\\n\\nAbstract: This study compares different methods to extract soil moisture information through the assimilation of Soil Moisture Active Passive (SMAP) observations. Neural network (NN) and physically-based SMAP soil moisture retrievals were assimilated into the National Aeronautics and Space Administration (NASA) Catchment model over the contiguous United States for April 2015 to March 2017. By construction, the NN retrievals are consistent with the global climatology of the Catchment model soil moisture. Assimilating the NN retrievals without further bias correction improved the surface and root zone correlations against in situ measurements from 14 SMAP core validation sites (CVS) by 0.12 and 0.16, respectively, over the model-only skill, and reduced the surface and root zone unbiased root-mean-square error (ubRMSE) by 0.005 m respectively. The assimilation reduced the average absolute surface bias against the CVS measurements by 0.009 m. Assimilating the NN retrievals after a localized bias correction yielded slightly lower surface correlation and ubRMSE improvements, but generally the skill differences were small. The assimilation of the physically-based SMAP Level-2 passive soil moisture retrievals using a global bias correction yielded similar skill improvements, as did the direct assimilation of locally bias-corrected SMAP brightness temperatures within the SMAP Level-4 soil moisture algorithm. The results show that global bias correction methods may be able to extract more independent information from SMAP observations compared to local bias correction methods, but without accurate quality control and observation error characterization they are also more vulnerable to adverse effects from retrieval errors related to uncertainties in the retrieval inputs and algorithm. Furthermore, the results show that using global bias correction approaches without a simultaneous re-calibration of the land model processes can lead to skill degradation in other land surface variables.\",\n \"Title: Real-Time Three-Dimensional Microwave Monitoring of Interstitial Thermal Therapy.\\nYear: 2018\\n\\nAbstract: We report a method for real-time threedimensional monitoring of thermal therapy through the use of noncontact microwave imaging. This method is predicated on using microwaves to image changes in the dielectric properties of tissue with changing temperature. Instead of the precomputed linear Born approximation that was used in prior work to speed up the frame-to-frame inversions, here we use the no...\",\n \"Title: Towards Multi-Frequency Soil Moisture Retrieval Using P- and L-Band Passive Microwave Sensing Technology.\\nYear: 2018\\n\\nAbstract: A fundamental limitation of current soil moisture remote sensing technology is that can only provide moisture information on the top 5 cm layer of soil at most, being one-tenth to one-quarter of the wavelength (21 cm at L-band; 1.4 GHz) using the current SMAP and SMOS soil moisture dedicated missions of NASA and ESA. Consequently, we have developed an airborne passive microwave sensing capability at P-band to develop a new state-of-the-art satellite concept that will provide soil moisture data for the top 10 cm layer of soil using radiometer observations at P-band (40 cm; 750 MHz). Not only would P-band provide soil moisture information on a soil layer thickness that more closely relates to that affecting crop and pasture growth, but it is expected to produce greater spatial coverage with improved accuracy to that from L-band. This is because P-band should be less affected by surface roughness conditions and have a reduced attenuation by the overlaying vegetation. This paper describes a series of small airborne field experiments at P-band, and presents some early results of P-band passive microwave observations in comparison with L-band and K-band passive microwave from initial trial flights.\",\n \"Title: A Method for Upscaling In Situ Soil Moisture Measurements to Satellite Footprint Scale Using Random Forests.\\nYear: 2017\\n\\nAbstract: Geophysical products generated from remotely sensed data require validation to evaluate their accuracy. Typically in situ measurements are used for validation, as is the case for satellite-derived soil moisture products. However, a large disparity in scales often exists between in situ measurements (covering meters to 10 s of meters) and satellite footprints (often hundreds of meters to several ki...\",\n \"Title: Spatial and Temporal Variability of Root-Zone Soil Moisture Acquired From Hydrologic Modeling and AirMOSS P-Band Radar.\\nYear: 2018\\n\\nAbstract: The accurate estimation of grid-scale fluxes of water, energy, and carbon requires consideration of subgrid spatial variability in root-zone soil moisture (RZSM). The NASA Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission represents the first systematic attempt to repeatedly map high-resolution RZSM fields using airborne remote sensing across a range of biomes. Here, we ...\",\n \"Title: 3-D Level Set Method for Joint Contrast and Shape Recovery in Microwave Imaging\\nYear: 2019\\n\\nAbstract: We propose a three-dimensional (3-D) fast level set method, which can estimate both object shape and dielectric contrast with reduced computational cost. In prior work, we presented a 2-D fast level set method that integrated the level set inversion within the Born iterative method (BIM). This approach significantly reduced the computational cost; however, it was limited to estimating object shape without providing any dielectric contrast inversion. In this paper, we extend our previous method to 3-D and add the capability to estimate dielectric contrast in addition to the shape. The contrast estimation is formulated as a separate step within the BIM iteration, such that the shape and contrast are estimated sequentially in each BIM iteration. This modular framework enables the freedom to choose any arbitrary constraints on the contrast in the cost function. Here, we demonstrate the applicability of a total-variation constraint for the contrast cost function. To validate the method, synthetic data are generated for objects within a 3-D imaging cavity and are then used to test for robustness against variations in object shape, size, position, and contrast. Further, the method is tested on MRI-derived numerical breast phantoms. The reconstructed images indicate that the method can produce accurate estimates of object location, shape, and size while recovering the contrast with an error lower than \\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"><tex-math notation=\\\"LaTeX\\\">$\\\\text{2}\\\\%$</tex-math></inline-formula>\\n.\",\n \"Title: Retrieval of Permafrost Active Layer Properties Using Time-Series P-Band Radar Observations\\nYear: 2019\\n\\nAbstract: We propose a method to estimate the active layer properties, including soil dielectric profiles and active layer thickness (ALT), in permafrost regions using time-series P-band polarimetric synthetic aperture radar (SAR) observations. The active layer and underlying permafrost are modeled as a three-layer dielectric structure with the layer dielectric constants representing the soil moisture and freeze-thaw state of the layer. To resolve the ambiguity of the retrieved layer thicknesses, an approach of finding the largest possible depths (LPDs) is combined with time-series observations, where the ALT is assumed time-invariant between the maximum thaw and before the upward freezing front rises significantly from the permafrost table. The LPD-assisted time-series retrieval algorithm is applied to the radar data acquired by the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) P-band SAR in August and October 2014 and 2015 over the Alaska North Slope. The results show that the retrieved ALT values are generally underestimated for the sites where the \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">in situ</italic>\\n ALT is larger than the P-band sensing depth, with a retrieval bias ranging from −0.05 to −0.24 m as validated against the \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">in situ</italic>\\n ALT collected at Circumpolar Active Layer Monitoring (CALM) sites. For the sites where the \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">in situ</italic>\\n ALT is smaller than 0.55 m, the retrieval errors are generally less than 0.1 m. The retrieval results also show that the active layer properties are strongly influenced by the land cover types at the regional scale, and not as much by the North–South temperature gradient across a 180-km-long transect along the Deadhorse flight line.\",\n \"Title: Validation Of Permafrost Active Layer Estimates From Airborne Sar Observations\\nYear: 2021\\n\\nAbstract: In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic and elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have emerged as a method for observing seasonal thaw subsidence, soil moisture, and ALT in permafrost regions. This study validates airborne SAR-derived ALT estimates in three regions of Alaska, USA using calibrated ground penetrating radar (GPR) geophysical data. The remotely sensed ALT estimates matched the field observations within uncertainty for 79% of locations. The average uncertainty for the GPR-derived ALT validation dataset was 0.14 m while the average uncertainty for the SAR-derived ALT in pixels coincident with GPR data was 0.19 m. In the region near Utqiavik, the remotely sensed ALT appeared slightly larger than field observations while in the Yukon-Kuskokwim Delta region, the remotely sensed ALT appeared slightly smaller than field observations. In the northern foothills of the Brooks Range, near Toolik Lake, there was minimal bias between the field data and remotely sensed estimates. These findings suggest that airborne SAR-derived ALT estimates compare well with in situ probing and GPR, making SAR an effective tool to monitor permafrost measurements.\",\n \"Title: A Versatile and Shelf-Stable Dielectric Coupling Medium for Microwave Imaging\\nYear: 2022\\n\\nAbstract: <italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Objective:</i>\\n To develop a new class of emulsions using a protein-based emulsifier as the coupling fluid for microwave imaging systems. \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Methods:</i>\\n In this paper, we provide a theoretical basis for engineering shelf-stable dielectric fluids, a step-by-step formulation method, and measurements of complex dielectric properties in the frequency range of 0.5-3 GHz, which can be applicable for many of the recent microwave imaging systems. \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Results:</i>\\n This medium was primarily designed for long-term stability while providing a controllable range of complex dielectric permittivities given different fractions of its constituents. Consequently, this emulsion shows dielectric stability in open air throughout a 7-day experiment and temperature insensitivity over the range of 0\\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"><tex-math notation=\\\"LaTeX\\\">${\\\\,^\\\\circ }$</tex-math></inline-formula>\\nC to 60\\n<inline-formula xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\"><tex-math notation=\\\"LaTeX\\\">${^\\\\circ }$</tex-math></inline-formula>\\n. \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Conclusions:</i>\\n This control over dielectric permittivity enables formulations that tune the background-to-target contrast to the linearizable regime of iterative inverse scattering algorithms. Accordingly, the emulsion conductivity can also be controlled and reduced to maintain the required signal-to-noise ratio within the dynamic range of the imaging system. The new formulation overcomes the practical challenges of engineering coupling fluids for microwave imaging systems, e.g., temporal stability, non-toxic, low sensitivity to temperature variation, and easy formulation from readily available and inexpensive materials. \\n<italic xmlns:mml=\\\"http://www.w3.org/1998/Math/MathML\\\" xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\">Significance:</i>\\n The achieved properties associated with this new fluid are of particular benefit to microwave imaging systems used in thermal therapy monitoring.\",\n \"Title: Embedded Temporal Convolutional Networks for Essential Climate Variables Forecasting\\nYear: 2022\\n\\nAbstract: Forecasting the values of essential climate variables like land surface temperature and soil moisture can play a paramount role in understanding and predicting the impact of climate change. This work concerns the development of a deep learning model for analyzing and predicting spatial time series, considering both satellite derived and model-based data assimilation processes. To that end, we propose the Embedded Temporal Convolutional Network (E-TCN) architecture, which integrates three different networks, namely an encoder network, a temporal convolutional network, and a decoder network. The model accepts as input satellite or assimilation model derived values, such as land surface temperature and soil moisture, with monthly periodicity, going back more than fifteen years. We use our model and compare its results with the state-of-the-art model for spatiotemporal data, the ConvLSTM model. To quantify performance, we explore different cases of spatial resolution, spatial region extension, number of training examples and prediction windows, among others. The proposed approach achieves better performance in terms of prediction accuracy, while using a smaller number of parameters compared to the ConvLSTM model. Although we focus on two specific environmental variables, the method can be readily applied to other variables of interest.\",\n \"Title: Sensitivity of Multifrequency Polarimetric SAR Data to Postfire Permafrost Changes and Recovery Processes in Arctic Tundra\\nYear: 2022\\n\\nAbstract: We used full-polarimetric L-band and P-band synthetic aperture radar (SAR) data collected from the recent NASA Arctic Boreal Vulnerability Experiment (ABoVE) airborne campaign and Sentinel-1 C-band dual-polarization data to understand the sensitivity of radar backscatter intensity and phase to fire-induced changes in the surface and subsurface soil processes in Arctic tundra underlain by permafrost. The 2007 Anaktuvuk River fire on the Alaska North Slope was used as a case study. At similar to 10-year postfire, we observed a strong increase (>similar to 3-4 dB) in the low-frequency radar backscatter in severely burned areas during the thaw season, in contrast to limited (<similar to 0.5 dB) C-band backscatter differences (VV and VH) between burned and unburned areas. However, C-band winter backscatter is generally higher (>1 dB) in burned areas than the adjacent unburned areas. Polarimetric decomposition analysis indicated a general trend toward more random surface scattering, and strong increases in double-bounce scattering and volume scattering power at both P- and L-band in the burned areas. The ice-rich yedoma region shows the largest backscatter increases in burned areas and the highest correlation with burn severity and microtopography changes. The above backscatter changes are attributed to increasing surface roughness and microtopography due to ice-wedge degradation and thermokarst development and increasing subsurface scattering due to an overall drier and deeper active layer in burned areas. Among all frequencies, P-band shows consistently larger contrast in backscatter power and phase between burned and unburned areas, which makes it potentially more useful to study fire-permafrost interactions in the Arctic over decadal time scales.\",\n \"Title: Wireless Sensor Network Informed UAV Path Planning for Soil Moisture Mapping\\nYear: 2022\\n\\nAbstract: Adaptive and targeted allocation of mobile sensing agents, in the form of unmanned aerial vehicles (UAVs) with software defined radar (UAV-SDRadar) payloads, enable mapping of surface soil moisture in regions where in situ wireless sensor networks (WSNs) undersample soil moisture or upscaling models perform poorly. This work presents an optimization-based UAV path planning methodology that seeks to maximize UAV flight coverage over areas where a complementing WSN yields upscaled soil moisture estimates with high uncertainty. By recursively mapping soil moisture over such areas, the combined UAV and WSN instrumentation can gradually capture the domain's true mean soil moisture. A series of numerical simulations are presented to demonstrate the algorithm's basic function while considering real-world and feasible operational scenarios.\",\n \"Title: Snow Depth Retrieval With an Autonomous UAV-Mounted Software-Defined Radar\\nYear: 2022\\n\\nAbstract: We present results from a field campaign to measure seasonal snow depth at Cameron Pass, Colorado, using a synthetic ultrawideband software-defined radar (SDRadar) implemented in commercially available Universal Software Radio Peripheral (USRP) software-defined radio hardware and flown on a small hexacopter unmanned aerial vehicle (UAV). We coherently synthesize an ultrawideband signal from stepped frequency 50-MHz subpulses across 600-2100-MHz frequency bands using a novel nonuniform nonlinear synthetic wideband waveform reconstruction technique that minimizes sweep time and completely eliminates problematic grating lobes and other processing artifacts traditionally seen in stepped waveform synthesis. We image seasonal snow across two transects: a 400-m open Meadow Transect and a 380-m forested transect. We present a surface detection algorithm that fuses data from LiDAR, global navigation satellite system (GNSS)/global positioning system (GPS), and features in the radargram itself to obtain high precision estimates of both snow and ground surface reflections, and thus total snow depth, represented as two-way travel time. The measurements are validated against independent ground-based ground-penetrating radar measurements with correlations coefficients as high as rho = 0.9 demonstrated. Finally, we compare backscattered radar data collected by the UAV-SDRadar while hovering proximal to a known snow pit with in situ measured snow dielectric profiles and demonstrate imaging of snow stratigraphy.\",\n \"Title: GNSS-R Soil Moisture Retrieval for Flat Vegetated Surfaces Using a Physics-Based Bistatic Scattering Model and Hybrid Global/Local Optimization\\nYear: 2022\\n\\nAbstract: This paper presents a soil moisture retrieval scheme from Cyclone Global Navigation Satellite System (CYGNSS) delay-Doppler maps (DDMs) over land. The proposed inversion method consists of a hybrid global and local optimization method and a physics-based bistatic scattering forward model. The forward model was developed for bare-to-densely vegetated terrains, and it predicts the circularly polarized bistatic radar cross section DDM of the land surface. This method was tested on both simulated DDMs and CYGNSS DDMs over the Soil Moisture Active Passive (SMAP) Yanco core validation site in Australia. About 250 CYGNSS DDMs from 2019 and 2020 over the Yanco site were used for validation. The simulated DDMs were for grassland and forest vegetation types. The vegetation type of the Yanco validation site was grassland. The vegetation water content (VWC) was 0.19 kg m(-2) and 4.89 kg m(-2) for the grassland and forest terrains, respectively. For the case when the surface roughness is known to the algorithm, the unbiased root mean square error (ubRMSE) of soil moisture estimates was less than 0.03 m(3) m(-3) while it was approximately 0.06 m(3) m(-3) and 0.09 m(3) m(-3) for the validation results from 2019 and 2020, respectively. The retrieval algorithm generally had enhanced performance for smaller values of soil moisture. For the case when both the soil moisture and surface roughness are unknown to the algorithm and only a single DDM is used for retrieval, the validation results showed an expected reduced performance, with an an ubRMSE of less than 0.12 m(3) m(-)(3).\",\n \"Title: Intercomparison of Electromagnetic Scattering Models for Delay-Doppler Maps Along a CYGNSS Land Track With Topography\\nYear: 2022\\n\\nAbstract: A comparison of three different electromagnetic scattering models for land surface delay-Doppler maps (DDMs) obtained from global navigation satellite system reflectometry (GNSS-R) along a Cyclone Global Navigation Satellite System (CYGNSS) track in the San Luis Valley, Colorado, USA, is presented. The three models are the analytical Kirchhoff solutions (AKS), the Soil And VEgetation Reflection Simulator (SAVERS), and the improved geometrical optics with topography (IGOT). Common inputs to the three models were defined by using field samples of soil moisture and texture, soil surface roughness measurements, and a digital elevation model (DEM). The resulting peak reflectivity profiles of the models and the CYGNSS data all had a range of 10 dB along the selected track, mainly due to the influence of topography. The reflectivities obtained from all three models agreed with one another within 2.4 dB along the full length of the track. The models also showed general agreement with the corresponding CYGNSS data, although the modeled profiles were higher than CYGNSS Science Data Record Version 3.1 by an average of 5 dB and also smoother. Additional characterization of fine-scale surface roughness is identified as an area for future work to improve model fidelity. An intercomparison of DDM structure for three selected acquisitions is also provided.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":85,"string":"85"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13375,"string":"13,375"}}},{"rowIdx":13376,"cells":{"question_id":{"kind":"string","value":"Sudha Ram"},"question":{"kind":"string","value":"Generate an abstract for the title \"Indoor Environmental Effects On Individual Wellbeing\" using the following items: 1. Built environment\n2. Instantaneous wellbeing\n3. Short-term stress response\n4. Indoor environmental factors\n5. Hidden Markov Model (HMM)"},"answer":{"kind":"string","value":"A growing literature demonstrates the impact of the built environment on human health and wellbeing. A wide range of factors such as daylight exposure, ambient noise and air quality may alter an individual's instantaneous state of wellbeing. Instantaneous state of wellbeing has been associated with variability in the physiological stress response. Our research goal is to capture the effect of indoor environment changes on short-term stress response of individuals. At an early stage in this research project, we demarcate our problem by posing three questions: (a) \"Which are the indoor environmental factors that correlate with heart rate variability?\" (b) \"Can episodic stress levels be identified using stress response patterns?\" (c) \"Can we optimize the overall wellbeing of individuals at workspace by controlling indoor environment?\". We briefly discuss our ongoing study setup and interim results. Thereafter, we propose a Hidden Markov Model (HMM) based framework to address the second question. Addressing the first two questions provides a foundation to address the third question which is the end goal of this study."},"correct_answer":{"kind":"string","value":"A growing literature demonstrates the impact of the built environment on human health and wellbeing. A wide range of factors such as daylight exposure, ambient noise and air quality may alter an individual's instantaneous state of wellbeing. Instantaneous state of wellbeing has been associated with variability in the physiological stress response. Our research goal is to capture the effect of indoor environment changes on short-term stress response of individuals. At an early stage in this research project, we demarcate our problem by posing three questions: (a) \"Which are the indoor environmental factors that correlate with heart rate variability?\" (b) \"Can episodic stress levels be identified using stress response patterns?\" (c) \"Can we optimize the overall wellbeing of individuals at workspace by controlling indoor environment?\". We briefly discuss our ongoing study setup and interim results. Thereafter, we propose a Hidden Markov Model (HMM) based framework to address the second question. Addressing the first two questions provides a foundation to address the third question which is the end goal of this study."},"documents":{"kind":"list like","value":["Title: Linking Biological Databases Semantically for Knowledge Discovery\nYear: 2008\n\nAbstract: Many important life sciences questions are aimed at studying the relationships and interactions between biological functions/processes and biological entities such as genes. The answers may be found by examining diverse types of biological/genomic databases. Finding these answers, however, requires accessing, and retrieving data, from diverse biological data sources. More importantly, sophisticated knowledge discovery processes involve traversing through large numbers of inherent links among various data sources. Currently, the links among data are either implemented as hyperlinks without explicitly indicating their meanings and labels, or hidden in a seemingly simple text format. Consequently, biologists spend numerous hours identifying potentially useful links and following each lead manually, which is time-consuming and error-prone. Our research is aimed at constructing semantic relationships among all biological entities. We have designed a semantic model to categorize and formally define the links. By incorporating ontologies such as Gene or Sequence ontology, we propose techniques to analyze the links embedded within and among data records, to explicitly label their semantics, and to facilitate link traversal, querying, and data sharing. Users may then ask complicated and ad hoc questions and even design their own workflow to support their knowledge discovery processes. In addition, we have performed an empirical analysis to demonstrate that our method can not only improve the efficiency of querying multiple databases, but also yield more useful information.","Title: Semantic Conflict Resolution Ontology (SCROL): An Ontology for Detecting and Resolving Data and Schema-Level Semantic Conflicts\nYear: 2004\n\nAbstract: Abstract--Establishing semantic interoperability among heterogeneous information sources has been a critical issue in the database community for the past two decades. Despite the critical importance, current approaches to semantic interoperability of heterogeneous databases have not been sufficiently effective. We propose a common ontology called Semantic Conflict Resolution Ontology (SCROL) that addresses the inherent difficulties in the conventional approaches, i.e., federated schema and domain ontology approaches. SCROL provides a systematic method for automatically detecting and resolving various semantic conflicts in heterogeneous databases. SCROL provides a dynamic mechanism of comparing and manipulating contextual knowledge of each information source, which is useful in achieving semantic interoperability among heterogeneous databases. We show how SCROL is used for detecting and resolving semantic conflicts between semantically equivalent schema and data elements. In addition, we present evaluation results to show that SCROL can be successfully used to automate the process of identifying and resolving semantic conflicts.","Title: A comprehensive framework for modeling set-based business rules during conceptual database design\nYear: 2005\n\nAbstract: Business rules are the basis of any organization. From an information systems perspective, these business rules function as constraints on a database helping ensure that the structure and content of the real world sometimes referred to as miniworld--is accurately incorporated into the database. It is important to elicit these rules during the analysis and design stage, since the captured rules are the basis for subsequent development of a business constraints repository. We present a taxonomy for set-based business rules, and describe an overarching framework for modeling rules that constrain the cardinality of sets. The proposed framework results in various types constraints, i.e.. attribute, class, participation, projection, co-occurrence, appearance and overlappinq, on a semantic model that supports abstractions like classification, generalization/specialization, aggregation and association. We formally define the syntax of our proposed framework in Backus-Naur Form and explicate the semantics using first-order logic. We describe partial ordering in the constraints and define the concept of metaconstraints, which can be used for automatic constraint consistency checking during the design stage itself. We demonstrate the practicality of our approach with a case study and show how our approach to modeling business rules seamlessly integrates into existing database design methodology. Via our proposed framework, we show how explicitly capturing data semantics will help bridge the semantic gap between the real world and its representation in an information system.","Title: Intelligent database design using the unifying semantic model\nYear: 1995\n\nAbstract: Research and development in the field of database systems has culminated in its widespread use. As usage has grown, the desire to link separate databases has resulted in substantial effort being directed towards the design of distributed database systems. A major research issue in designing such systems is the definition of a formal model that can be used to capture the semantics of the individual databases. This paper presents a semantic model called the Unifying Semantic Model (USM) and a software tool using it. The USM can be used for modeling the complex interrelationships and semantics found in a manufacturing environment. It is based on enhancements to existing semantic models. It can serve as a formal specification and documentation tool for databases. It can provide a means of specifying the Universe of Discourse for any interchange of information.","Title: Entity identification for heterogeneous database integration: a multiple classifier system approach and empirical evaluation\nYear: 2005\n\nAbstract: Entity identification, i.e., detecting semantically corresponding records from heterogeneous data sources, is a critical step in integrating the data sources. The objective of this research is to develop and evaluate a novel multiple classifier system approach that improves entity identification accuracy. We apply various classification techniques drawn from statistical pattern recognition, machine learning, and artificial neural networks to determine whether two records from different data sources represent the same real-world entity. We further employ a variety of ways to combine multiple classifiers for improved classification accuracy. In this paper, we report on some promising empirical results that demonstrate performance improvement by combining multiple classifiers.","Title: HyperIntelligence: the next frontier\nYear: 1990\n\nAbstract: The authors discuss how mental models may be used to organize an individual's thoughts while forming a plan. A hypermedia system, SPRINT, is described which supports an explicit representation of a mental model as a network of associations among the elements of a strategic plan.","Title: Understanding database design expertise\nYear: 1995\n\nAbstract: Database design is a complex and time-consuming process. In order to automate database design, an understanding of the nature of expertise that goes into the design process is needed. Although a number of expert systems have been developed to assist or replace a database designer, database design expertise has not been examined in any detail, This paper proposes a conceptual framework for explaining this type of expertise. The components of the framework are applied to each phase of the design process and used to provide guidelines for the level of expertise developers might strive to obtain. Several representative systems are analyzed, based on the framework, to explore the degree to which expertise is being captured. Implications for the future development of database design expert systems are discussed.","Title: Provenance Management in BioSciences\nYear: 2010\n\nAbstract: Data provenance is becoming increasingly important for biosciences with the advent of large-scale collaborative environments\n such as the iPlant collaborative, where scientists collaborate by using data that they themselves did not generate. To facilitate\n the widespread use and sharing of provenance, ontologies of provenance need to be developed to enable the capture and standardized\n representation of provenance for biosciences. Working with researchers from the iPlant Tree of Life (iPToL) Grand Challenge\n Project, we developed a domain ontology of provenance for phylogenetic analysis. Relying on the conceptual graph formalism,\n we describe the process of developing the provenance ontology based on the W7 model, a generic ontology of data provenance.\n This domain ontology provides a structured model for harvesting, storing and querying provenance. We also illustrate how the\n harvested data provenance based on our ontology can be used for different purposes.","Title: Database design and querying within the fuzzy semantic model\nYear: 2007\n\nAbstract: Fuzzy semantic model (FSM) is a data model that uses basic concepts of semantic modeling and supports handling fuzziness, uncertainty and imprecision of real-world at the attribute, entity and class levels. The paper presents the principles and constructs of the FSM. It proposes ways to define the membership functions within all the constructs of the FSM. In addition, it provides a proposal for specifying FSM schema and introduce a query language adapted to FSM-based databases.","Title: Augmenting a Conceptual Model with Geospatiotemporal Annotations\nYear: 2004\n\nAbstract: While many real-world applications need to organize data based on space (e.g., geology, geomarketing, environmental modeling) and/or time (e.g., accounting, inventory management, personnel management), existing conventional conceptual models do not provide a straightforward mechanism to explicitly capture the associated spatial and temporal semantics. As a result, it is left to database designers to discover, design, and implement驴on an ad hoc basis驴the temporal and spatial concepts that they need. We propose an annotation-based approach that allows a database designer to focus first on nontemporal and nongeospatial aspects (i.e., \"what驴) of the application and, subsequently, augment the conceptual schema with geospatiotemporal annotations (i.e., \"when驴 and \"where驴). Via annotations, we enable a supplementary level of abstraction that succinctly encapsulates the geospatiotemporal data semantics and naturally extends the semantics of a conventional conceptual model. An overarching assumption in conceptual modeling has always been that expressiveness and formality need to be balanced with simplicity. We posit that our formally defined annotation-based approach is not only expressive, but also straightforward to understand and implement.","Title: An architecture for distributed knowledge based-systems\nYear: 1991\n\nAbstract: Many management information systems have requirements that are inherently distributed, both logically and physically, however, no adequate architectures exist which allow multiple knowledge bases and databases to be shared and integrated. An architecture for Distributed Knowledge-Based Systems (DKBS) is presented which satisfies these requirements. A Distributed Knowledge Base Management System (DKBMS) is described which manages the meta-knowledge necessary to coordinate multiple local Knowledge-Based Systems (KBSs). We propose an object-oriented design for implementing the DKBMS structure and the communication protocol which connects the DKBMS with each of the KBSs. An application is described where the DKBS architecture might assist managers to integrate several KBSs which represent parts of a strategic plan.","Title: Panel: new directions for conceptual modeling\nYear: 2011\n\nAbstract: This panel examines potential opportunities for conceptual modeling research in new domains.","Title: Resource Discovery and Intelligent Image Retrieval in a Distributed Environment\nYear: 1997\n\nAbstract: Remote sensing satellites are generating largeamounts of (image) data at different levels oftemporal, spatial and spectral resolution, with varyinglevels of detail, and at various stages of processingwith a variety of algorithms. This bewildering arrayof data sources is going to mandate a new class ofinformation retrieval systems to help end-users accessthe networked information resources effectively. Inthis paper, we propose intelligent agent basedmechanisms to locate the appropriate sources ofsatellite data, processing algorithms, and ancillarydata that may be required at various levels ofprocessing to answer different types of temporal andspatial queries.","Title: Integrating information systems technologies to support consultation in an information center\nYear: 1992\n\nAbstract: This paper presents an approach for integrating different types of information systems technologies to support the functions of an information center (IC). A knowledge-based system, information center expert/help service (ICE/H), has been developed to provide support for the help services of an IC. A general process model to represent the consultation process in an IC is described. Based on this model, an architecture has been developed to support the consultation process. The architecture depicts the use of a knowledge management system, a data management system and a communication (e-mail) system to emulate the consultation process. The ICE/H system has been implemented using this architecture to support an IC with 5000 users.","Title: Semantics-Based Transaction Processing for Real-Time Databases: The Case of Automated Stock Trading\nYear: 1999\n\nAbstract: <P>In the future, automated stock trading (AST) databases will need to support execution of transactions with time constraints similar to that discussed in real-time databases. Transactions in AST databases repeat from a predictable set of transaction classes where the logical read-sets and write-sets of these classes can be established a priori. We propose a novel transaction management mechanism that exploits this a priori knowledge of data requirements to minimize wasted resources and transaction restarts inherent in existing real-time transaction processing mechanisms based on dynamic acquisition of resources. Preanalysis provides a mechanism to incorporate transaction semantics, identify potentially detrimental conflicts, and induce favorable serialization orders before transactions execute. By blocking potentially conflicting transactions, we incorporate an implicit overload management technique. Scheduling decisions can be made efficient to complement serialization orders, thus reducing unnecessary transaction restarts. Our protocol is evaluated using simulation and is shown to outperform existing real-time concurrency control mechanisms under various workload and resource parameters.</P>","Title: On augmenting database design-support environments to capture the geo-spatio-temporal data semantics\nYear: 2006\n\nAbstract: A database design-support environment supports a data analyst in eliciting, articulating, specifying and validating data-related requirements. Extant design-support environments--based on conventional conceptual models--do not adequately support applications that need to organize data based on time (e.g., accounting, portfolio management, personnel management) and/or space (e.g., facility management, transportation, logistics). For geo-spatio-temporal applications, it is left to database designers to discover, design and implement--on an ad-hoc basis--the temporal and geospatial concepts that they need to represent the miniworld. To elicit the geo-spatio-temporal data semantics, we characterize guiding principles for augmenting the conventional conceptual database design approach, present our annotation-based approach, and illustrate how our proposed approach can be instantiated via a proof-of-concept prototype. Via a proof-of-concept database design-support environment, we exemplify our annotation-based approach, and show how segregating \"what\" from \"when/where\" via annotations satisfies ontologic- and cognition-based requirements, dovetails with existing database design methodologies, results in upward-compatible conceptual as well as XML schemas, and provides a straightforward mechanism to extend extant design-support environments.","Title: Sharing News Articles Using 140 Characters: A Diffusion Analysis on Twitter\nYear: 2012\n\nAbstract: Is it possible to effectively spread news articles to a large audience using 140 characters? How does the microblogging website Twitter get used as a platform for the news media agencies to create awareness about the articles they publish on a daily basis? Our study of the diffusion patterns of news articles from 12 popular news sources, including BBC, New York Times, and Mash able on Twitter reveals that a large number of users not only consume and comment on these news articles but also share them in different ways. Combining the methods of network and temporal analyses, we examine and report on how news articles diffuse on Twitter, and how different propagation mechanisms result in different life spans for news articles.","Title: Using a Network Analysis Approach for Organizing Social Bookmarking Tags and Enabling Web Content Discovery\nYear: 2012\n\nAbstract: This article describes an innovative approach to reorganizing the tag space generated by social bookmarking services. The objective of this work is to enable effective search and discovery of Web content using social bookmarking tags. Tags are metadata generated by users for Web content annotation. Their potential as effective Web search and discovery tool is hindered by challenges such as, the tag space being untidy due to ambiguity, and hidden or implicit semantics. Using a novel analytics approach, we conducted network analyses on tags and discovered that tags are generated for different purposes and that there are inherent relationships among tags. Our approach can be used to extract the purposes of tags and relationships among the tags and this information can be used as facets to add structure and hierarchy to reorganize the flat tag space. The semantics of relationships and hierarchy in our proposed faceted model of tags enable searches on annotated Web content in an effective manner. We describe the implementation of a prototype system called FASTS to demonstrate feasibility and effectiveness of our approach.","Title: Practical aspects of teaching an applied database course\nYear: 1996\n\nAbstract: The information systems curriculum recommendations proposed by ACM (Nunamaker et al., 1982), IFIP (Buckingham et al., 1987), DPMA (1991), and the recent ACM/AIS/DPMA (Couger et al., 1995, 1997) contain an overlapping core and several electives. Coverage of database concepts is required by all of the three curriculum recommendations for the development of information systems professionals. An important component of this requirement is learning the practical aspects of developing information systems by using databases In this paper we will present our experiences and recommendations in implementing this important aspect of teaching database courses within the information systems curriculum. In particular we will a) discuss management of field projects, including their benefits and pitfalls; and 2) make recommendations on fools and technologies available for implementation within a class room environment.","Title: Constrained cascade generalization of decision trees\nYear: 2004\n\nAbstract: While decision tree techniques have been widely used in classification applications, a shortcoming of many decision tree inducers is that they do not learn intermediate concepts, i.e., at each node, only one of the original features is involved in the branching decision. Combining other classification methods, which learn intermediate concepts, with decision tree inducers can produce more flexible decision boundaries that separate different classes, potentially improving classification accuracy. We propose a generic algorithm for cascade generalization of decision tree inducers with the maximum cascading depth as a parameter to constrain the degree of cascading. Cascading methods proposed in the past, i.e., loose coupling and tight coupling, are strictly special cases of this new algorithm. We have empirically evaluated the proposed algorithm using logistic regression and C4.5 as base inducers on 32 UCI data sets and found that neither loose coupling nor tight coupling is always the best cascading strategy and that the maximum cascading depth in the proposed algorithm can be tuned for better classification accuracy. We have also empirically compared the proposed algorithm and ensemble methods such as bagging and boosting and found that the proposed algorithm performs marginally better than bagging and boosting on the average.","Title: Communication requirements and network evaluation within electronic meeting system environments\nYear: 1991\n\nAbstract: One of the key issues in the design and implementation of Electronic Meeting Systems (EMS) is the identification of appropriate support for computer commununications. Lack of adequate communication support can create a bottleneck in the use of EMS. Our objective is to identify the communication needs of several different EMS environments and to discuss an approach that can be used to evaluate the required communication support. We then use this approach to benchmark the performance of two Local Area Network (LAN) operating systems (IBM LAN program and Novell Netware) and three network servers (IBM PS/2 models 50, 60 and 80) in one EMS environment. While network operating systems have received comparatively less attention in LAN evaluation and design, fully 75% of the response time in some configurations was due solely to the network operating system. The Novell Netware software running on the IBM PS/2 model 50 server provided at least as great speed at lower cost than any other configuration tested. For the small files common to one style of EMS environment (i.e. under 2.5K), response time was not affected by the size of the file but rather was determined by the fixed overhead imposed by the network operating system.","Title: Group data base design: addressing the view modeling problem\nYear: 1995\n\nAbstract: Today's organizations increasingly depend on the use of data base technology to manage their operations. Advances in technology have resulted in increasing the number and complexity of these data bases. Despite their growing complexity, all data bases have one thing in common: each must have gone through either a formal or an informal design process. Data bases must mirror reality accurately, and thus the design process must better capture that reality. The heart of the design process is the conceptual design, data model mapping, and physical design. Our research focuses on providing automated support for the first of these, e.g., conceptual design. Conceptual design is known to be a very difficult and time-consuming phase in the development of data base applications. This article describes the architecture, implementation, and use of a distributed graphical group data base design system. The group view modeling system (GVMS) is implemented in Microsoft Windows for networked personal computers. The main purpose of GVMS is to allow multiple designers (or users) to share conceptual design information in real time and resolve design conflicts through the electronic medium. The underlying data model, semantic data model, is extended to include distribution information as well as transactions and is represented as an extended entity relationship model. Diagram management techniques are implemented to aid in simplifying large complex designs. A small study demonstrated that groups of data base designers who define their view collectively outperform individuals.","Title: A Blackboard-Based Cooperative System for Schema Integration\nYear: 1995\n\nAbstract: We describe a four-level blackboard architecture that supports schema integration and provide a detailed description of the communication among human and computational agents that this system allows.Today's corporate information system environments are heterogeneous, consisting of multiple and independently managed databases. Many applications that assist decision making call for access to data from multiple heterogeneous databases. To facilitate this, there needs to be an integrated representation of the underlying databases that allows users to query multiple databases simultaneously. The process of deriving this integrated representation is called schema integration.Schema integration is time consuming and complex, as it requires a thorough understanding of the underlying database semantics. Since no data model can capture the entire real world semantics of each database's objects, this process requires human agent assistance. Although certain aspects of schema integration can be automated, interaction with designers and users is still necessary. In this article, we describe how blackboard architectures can facilitate the communication among human and computational agents for schema integration.","Title: Research Commentary: An Agenda for Information Technology Research in Heterogeneous and Distributed Environments\nYear: 2000\n\nAbstract: Application-driven, technology-intensive research is critically needed to meet the challenges of globalization, interactivity, high productivity, and rapid adaptation faced by business organizations. Information systems researchers are uniquely positioned to conduct such research, combining computer science, mathematical modeling, systems thinking, management science, cognitive science, and knowledge of organizations and their functions. We present an agenda for addressing these challenges as they affect organizations in heterogeneous and distributed environments. We focus on three major capabilities enabled by such environments: Mobile Computing, Intelligent Agents, and Net-Centric Computing. We identify and define important unresolved problems in each of these areas and propose research strategies to address them.","Title: DISTIL: A Design Support Environment for Conceptual Modeling of Spatio-temporal Requirements\nYear: 2001\n\nAbstract: We describe DISTIL (DIstributed design of SpaTIo-temporaL data), a web-based conceptual modeling prototype system that can help capture the semantics of spatio-temporal data. Via DISTIL, we describe an annotation-based approach that divides spatio-temporal conceptual design into two steps: first capture the current reality of an application using a conventional conceptual model without considering the spatial aspects, and only then annotate the schema with the spatio-temporal semantics of the application. A database development team can use DISTIL to capture and validate their spatio-temporal data requirements. Using DISTIL we demonstrate that the annotation-based approach for capturing spatio-temporal requirements is straightforward to implement, satisfies ontology-based and cognition-based requirements, and integrates seamlessly into the existing database design methodologies.","Title: Examining lists on Twitter to uncover relationships between following, membership and subscription\nYear: 2013\n\nAbstract: We report on an exploratory analysis of pairwise relationships between three different forms of information consumption on Twitter viz., following, listing and subscribing. We develop a systematic framework to examine the relationships between these three forms. Using our framework, we conducted an empirical analysis of a dataset from Twitter. Our results show that people not only consume information by explicitly following others, but also by listing and subscribing to lists and that the people they list or subscribe to are not the same as the ones they follow. Our work has implications for understanding information propagation and diffusion via Twitter and for generating recommendations for adding users to lists, subscribing and merging or splitting them.","Title: Next-Generation Team-Science Platform for Scientific Collaboration\nYear: 2011\n\nAbstract: Emerging research on team science aims at better understanding the key contextual factors during the trans-disciplinary scientific collaboration process and enhancing the outcomes of large-scale collaborative research programs. Team science can range from a few participants working at the same site to numerous researchers dispersed across multiple geographic and organizational venues. This article outlines the fundamental conceptual framework of a next-generation team-science-enabling platform (TSEP).","Title: Advances In Data Modeling Research\nYear: 2005\n\nAbstract: In this paper, we summarize the discussions of the panel on \"Advances in Data Modeling Research,\" held at the Americas Conference on Information Systems (AMCIS) in 2005. We focus on four primary areas where data modeling research offers rich opportunities: spatio-temporal semantics, genome research, ontological analysis and empirical evaluation of existing models. We highlight past work in each area and also discuss open questions, with a view to promoting future research in the overall data modeling area.","Title: Entity matching across heterogeneous data sources: An approach based on constrained cascade generalization\nYear: 2008\n\nAbstract: To integrate or link the data stored in heterogeneous data sources, a critical problem is entity matching, i.e., matching records representing semantically corresponding entities in the real world, across the sources. While decision tree techniques have been used to learn entity matching rules, most decision tree learners have an inherent representational bias, that is, they generate univariate trees and restrict the decision boundaries to be axis-orthogonal hyper-planes in the feature space. Cascading other classification methods with decision tree learners can alleviate this bias and potentially increase classification accuracy. In this paper, the authors apply a recently-developed constrained cascade generalization method in entity matching and report on empirical evaluation using real-world data. The evaluation results show that this method outperforms the base classification methods in terms of classification accuracy, especially in the dirtiest case.","Title: Modeling Spatial and Temporal Set-Based Constraints During Conceptual Database Design\nYear: 2012\n\nAbstract: From a database perspective, business constraints provide an accurate picture of the real world being modeled and help enforce data integrity. Typically, rules are gathered during requirements analysis and embedded in code during the implementation phase. We propose that the rules be explicitly modeled during conceptual design, and develop a framework for understanding and classifying spatiotemporal set-based (cardinality) constraints and an associated syntax. The constraint semantics are formally specified using first-order logic. Modeling rules in conceptual design ensures they are visible to designers and users and not buried in application code. The rules can then be semiautomatically translated into logical design triggers yielding productivity gains. Following the principles of design science research, we evaluate the framework's expressiveness and utility with a case study.","Title: Multicriterion Market Segmentation: A New Model, Implementation, and Evaluation\nYear: 2010\n\nAbstract: Market segmentation is inherently a multicriterion problem even though it has often been modeled as a single-criterion problem in the traditional marketing literature and in practice. This paper discusses the multicriterion nature of market segmentation and develops a new mathematical model that addresses this issue. A new method for market segmentation based on multiobjective evolutionary algorithms, called MMSEA, is developed. It complements existing segmentation methods by optimizing multiple objectives simultaneously, searching for globally optimal solutions, and approximating a set of Pareto-optimal solutions. We have applied and evaluated this method in two empirical studies for two firms from distinct industries: descriptive segmentation of the cell phone service market from a dual-value creation perspective and predictive segmentation of retail customers based on profit and customer sociodemographic attributes. The results provide decision makers with compelling alternatives and enhanced flexibility currently missing in existing market segmentation methods.","Title: Common citation analysis and technology overlap factor: an empirical investigation of litigated patents using network analysis\nYear: 2012\n\nAbstract: Companies incur huge costs in filing and defending patent lawsuits. A part of the problem arises from the fact that companies do not have a comprehensive understanding of the patents that they have cited and the patents that have cited their patents. By empirically analyzing the forward and backward citations of a set of litigated patents in the smart phone industry, we provide a method for profiling patents and identifying citation patterns. Our results show that while some patents share common forward and backward citations, others do not share any backward citations but share a lot of forward citations. We hypothesize that this maybe an indication of the convergence of different types of technologies. We also propose a new metric - Technology Overlap Factor - that can help in identifying convergence. In doing so, we provide a preliminary framework for further investigation and for building a patent analysis software system.","Title: A Comprehensive Framework Towards Information Sharing Between Government Agencies\nYear: 2007\n\nAbstract: Recently, there has been increased interest in sharing digitized information between government agencies, with the goals of improving security, reducing costs, and offering better quality service to users of government services. The bulk of previous work in interagency information sharing has focused largely on the sharing of structured information among heterogeneous data sources, whereas government agencies need to share data with varying degrees of structure ranging from free text documents to relational data. In this work, we explore the different technologies available to share information. Specifically, our framework discusses the optional data storage mechanisms required to support a Service Oriented Architecture (SOA). We compare XML document, free text search engine, and relational database technologies and analyze the pros and cons of each approach. We explore these options along the dimensions of information definition, information storage, the access to this information, and finally the maintenance of shared information.","Title: GeoCosm: A Semantics-Based Approach for Information Integration of Geospatial Data\nYear: 2001\n\nAbstract: Information integration implies access to distributed information sources without interfering with the autonomy of the underlying\n data sources. Integration of distributed geospatial data requires a mechanism for selecting the data sources and performing\n data processing operations on the selected sources efficiently. We describe a semantics-based information integration approach\n that uses a spatio-temporal semantic model to define the geospatial information content of the sources, employs a conflict\n resolution ontology to resolve semantic heterogeneity, and uses geospatial metadata to help the users evaluate usefulness\n of the available data sources. We show how the captured metadata can be used for efficient query planning. Based on our proposed\n approach, we are developing GeoCosm, a web-based prototype that would help integrate autonomous distributed heterogeneous\n geospatial data.","Title: IAIS: A Methodology to Enable Inter-Agency Information Sharing In eGovernment\nYear: 2003\n\nAbstract: Recently, there has been increased interest in information sharing among government agencies, with a view toward improving security, reducing costs and offering better quality service to users of government services. In this work, the authors complement earlier work by proposing a comprehensive methodology called IAIS (Inter Agency Information Sharing) that uses XML to facilitate the definition of information that needs to be shared, the storage of such information, the access to this information and finally the maintenance of shared information. The authors compare IAIS with two alternate methodologies to share information among agencies, and analyze the pros and cons of each. They also show how IAIS leverages the recently proposed XML (extensible markup language) standard to allow for inclusion of various groups' viewpoints when determining what information should be shared and how it should be structured.","Title: Understanding the semantics of data provenance to support active conceptual modeling\nYear: 2006\n\nAbstract: Data Provenance refers to the lineage of data including its origin, key events that occur over the course of its lifecycle, and other details associated with data creation, processing, and archiving. We believe that tracking provenance enables users to share, discover, and reuse the data, thus streamlining collaborative activities, reducing the possibility of repeating dead ends, and facilitating learning. It also provides a mechanism to transition from static to active conceptual modeling. The primary goal of our research is to investigate the semantics or meaning of data provenance. We describe the W7 model that represents different components of provenance and their relationships to each other. We conceptualize provenance as a combination of seven interconnected elements including \"what\", \"when\", \"where\", \"how\", \"who\", \"which\" and \"why\". Each of these components may be used to track events that affect data during its lifetime. A homeland security example illustrates how current conceptual models can be extended to embed provenance.","Title: Semantic-Model Support for Geographic Information Systems\nYear: 1999\n\nAbstract: Natural resource management is an important issue that uses large amounts of spatial and temporal data. It is risky to predict the consequences of resource management decisions without accurately understanding the interaction of ecosystems over a large region.A geographical information system describes objects from the real world in terms oflocation--geographic positions, attributes that are unrelated to position, such as soil type, elevation, and demographics, spatial relationships--how objects are linked, and temporal information--the evolution of both spatial and nonspatial data over time. The authors collaborated on this project to develop a computer environment that enables ecological researchers to analyze and solve problems concerning real ecosystems. Their system brings together and makes accessible data from a variety of heterogeneous databases.Such efforts have a high level of complexity when they seek to produce credible solutions to real-world management concerns. Over the past several years, the term synthetic environment has emerged to describe this type of simulation system.","Title: Combining schema and instance information for integrating heterogeneous data sources\nYear: 2007\n\nAbstract: Determining the correspondences among heterogeneous data sources, which is critical to integration of the data sources, is a complex and resource-consuming task that demands automated support. We propose an iterative procedure for detecting both schema-level and instance-level correspondences from heterogeneous data sources. Cluster analysis techniques are used first to identify similar schema elements (i.e., relations and attributes). Based on the identified schema-level correspondences, classification techniques are used to identify matching tuples. Statistical analysis techniques are then applied to a preliminary integrated data set to evaluate the relationships among schema elements more accurately. Improvement in schema-level correspondences triggers another iteration of an iterative procedure. We have performed empirical evaluation using real-world heterogeneous data sources and report in this paper some promising results (i.e., incremental improvement in identified correspondences) that demonstrate the utility of the proposed iterative procedure.","Title: Using a knowledge learning framework to predict errors in database design\nYear: 2014\n\nAbstract: Conceptual data modeling is a critical but difficult part of database development. Little research has attempted to find the underlying causes of the cognitive challenges or errors made during this stage. This paper describes a Modeling Expertise Framework (MEF) that uses modeler expertise to predict errors based on the revised Bloom's taxonomy (RBT). The utility of RBT is in providing a classification of cognitive processes that can be applied to knowledge activities such as conceptual modeling. We employ the MEF to map conceptual modeling tasks to different levels of cognitive complexity and classify current modeler expertise levels. An experimental exercise confirms our predictions of errors. Our work provides an understanding into why novices can handle entity classes and identifying binary relationships with some ease, but find other components like ternary relationships difficult. We discuss implications for data modeling training at a novice and intermediate level, which can be extended to other areas of Information Systems education and training.","Title: Toward semantic interoperability of heterogeneous biological data sources\nYear: 2005\n\nAbstract: Genomic researchers use a number of heterogeneous data sources including nucleotides, protein sequences, 3-D Protein structures, taxonomies, and research publications such as MEDLINE. This research aims to discover as much biological knowledge as possible about the properties and functions of the structures such as DNA sequences and protein structures and to explore the connections among all the data, so that the knowledge can be used to improve human lives. Currently it is very difficult to connect all of these data sources seamlessly unless all the data is transformed into a common format with an id connecting all of them. The state-of-the-art facilities for searching these data sources provide interfaces through which scientists can access multiple databases. Most of these searches are primarily text based, requiring users to specify keywords using which the systems search through each individual data source and returns results. The user is then required to create the connections between the results from each source. This is a major problem because researchers do not always know how to create these connections. To solve this problem we propose a semantics-based mechanism for automatically linking and connecting the various data sources. Our approach is based on a model that explicitly captures the semantics of the heterogeneous data sources and makes them available for searching. In this talk I will discuss issues related to capturing the semantics of biological data and using these semantics to automate the integration of diverse heterogeneous sources.","Title: FASTS: FAcets structured tag space – a novel approach to organize and reuse social bookmarking tags\nYear: 2010\n\nAbstract: Social bookmarking tools are generating an enormous pool of metadata describing and categorizing web resources The value of these metadata in the form of tags can be fully realized only when they are shared and reused for web search and retrieval The research described in this paper proposes a facet classification mechanism, and a tag relationship ontology to organize tags into a meaningful and intuitively useful structure We have implemented a web-based prototype system to effectively search and browse bookmarked web resources using this approach We collected real tag data from del.icio.us for a wide range of popular domains We analyzed, processed, and organized these tags to demonstrate the effectiveness and utility of our approach for tag organization and reuse.","Title: Information systems interoperability: What lies beneath?\nYear: 2004\n\nAbstract: Interoperability is the most critical issue facing businesses that need to access information from multiple information systems. Our objective in this research is to develop a comprehensive framework and methodology to facilitate semantic interoperability among distributed and heterogeneous information systems. A comprehensive framework for managing various semantic conflicts is proposed. Our proposed framework provides a unified view of the underlying representational and reasoning formalism for the semantic mediation process. This framework is then used as a basis for automating the detection and resolution of semantic conflicts among heterogeneous information sources. We define several types of semantic mediators to achieve semantic interoperability. A domain-independent ontology is used to capture various semantic conflicts. A mediation-based query processing technique is developed to provide uniform and integrated access to the multiple heterogeneous databases. A usable prototype is implemented as a proof-of-concept for this work. Finally, the usefulness of our approach is evaluated using three cases in different application domains. Various heterogeneous datasets are used during the evaluation phase. The results of the evaluation suggest that correct identification and construction of both schema and ontology-schema mapping knowledge play very important roles in achieving interoperability at both the data and schema levels.","Title: Design science in information systems research\nYear: 2004\n\nAbstract: Two paradigms characterize much of the research in the Information Systems discipline: behavioral science and design science. The behavioral-science paradigm seeks to develop and verify theories that explain or predict human or organizational behavior. The design-science paradigm seeks to extend the boundaries of human and organizational capabilities by creating new and innovative artifacts. Both paradigms are foundational to the IS discipline, positioned as it is at the confluence of people, organizations, and technology. Our objective is to describe the performance of design-science research in Information Systems via a concise conceptual framework and clear guidelines for understanding, executing, and evaluating the research. In the design-science paradigm, knowledge and understanding of a problem domain and its solution are achieved in the building and application of the designed artifact. Three recent exemplars in the research literature are used to demonstrate the application of these guidelines. We conclude with an analysis of the challenges of performing high-quality design-science research in the context of the broader IS community.","Title: A model for the design of distributed databases (abstract only)\nYear: 1985\n\nAbstract: This research is addressed towards solving a problem which falls under the general class of File Allocation Problems (FAP). The main purpose here is to provide a tool for the designer of a distributed database system. With an increasing number of enterprises tending towards distributed systems, a major research question that has come up is how to allocate resources (databases and programs) in a distributed environment. This question has been addressed by formulating a nonlinear integer programming model. Though the same issue has been addressed several times in the past, there is a major difference between the model developed here and all the other models. None of the models in the past have tried to solve the FAP by taking into account the concurrency control mechanism being used. This is a major deficiency of these models because allocation of files is partly based on the communication flows in a network of computers. The communication flows in turn are based on the concurrency control mechanism. It is this weakness that the research here has attempted to overcome by designing a more realistic model.","Title: Who does what: Collaboration patterns in the wikipedia and their impact on article quality\nYear: 2011\n\nAbstract: The quality of Wikipedia articles is debatable. On the one hand, existing research indicates that not only are people willing to contribute articles but the quality of these articles is close to that found in conventional encyclopedias. On the other hand, the public has never stopped criticizing the quality of Wikipedia articles, and critics never have trouble finding low-quality Wikipedia articles. Why do Wikipedia articles vary widely in quality? We investigate the relationship between collaboration and Wikipedia article quality. We show that the quality of Wikipedia articles is not only dependent on the different types of contributors but also on how they collaborate. Based on an empirical study, we classify contributors based on their roles in editing individual Wikipedia articles. We identify various patterns of collaboration based on the provenance or, more specifically, who does what to Wikipedia articles. Our research helps identify collaboration patterns that are preferable or detrimental for article quality, thus providing insights for designing tools and mechanisms to improve the quality of Wikipedia articles.","Title: The relational model is dead, SQL is dead, and I don't feel so good myself\nYear: 2013\n\nAbstract: We report the opinions expressed by well-known database researchers on the future of the relational model and SQL during a panel at the International Workshop on Non-Conventional Data Access (NoCoDa 2012), held in Florence, Italy in October 2012 in conjunction with the 31st International Conference on Conceptual Modeling. The panelists include: Paolo Atzeni (Università Roma Tre, Italy), Umeshwar Dayal (HP Labs, USA), Christian S. Jensen (Aarhus University, Denmark), and Sudha Ram (University of Arizona, USA). Quotations from movies are used as a playful though effective way to convey the dramatic changes that database technology and research are currently undergoing.","Title: A Semantic Foundation for Provenance Management.\nYear: 2012\n\nAbstract: Provenance is a term used to describe the lineage, history, or origin of an object. While provenance originated from the art world, it is now becoming increasingly important in the context of digital objects on the World Wide Web. Large scale scientific collaborations and social media platforms on the web have enabled production and sharing of a variety of digital objects on the web. With the proliferation and sharing of such objects, which include documents, pictures, videos, and more, questions such as “where did this object come from?”, “who else is using this object?” and “for what purpose was it generated?” are becoming increasingly common. To ensure that digital objects from different sources can be trusted and used appropriately, it is imperative that the provenance of the digital objects be tracked, recorded, and made available to its users. In this work, we attempt to provide a foundation for understanding provenance, clearly define the semantics of provenance, distinguish provenance from “uses or application” of provenance, suggest a mechanism for managing provenance, and provide important directions for research in provenance management.","Title: Elitist and Ensemble Strategies for Cascade Generalization\nYear: 2006\n\nAbstract: Several methods have been proposed for cascading other classification algorithms with decision tree learners to alleviate the representational bias of decision trees and, potentially, to improve classification accuracy. Such cascade generalization of decision trees increases the flexibility of the decision boundaries between classes and promotes better fitting of the training data. However more flexible models may not necessarily lead to more predictive power. Because of polential overfitting problems, the true classification accuracy on test data may not increase. Recently, a generic method for cascade generalization has been proposed. The method uses a parameter-the maximum cascading depth-to constrain the degree that other classification algorithms are cascaded with decision tree learners. A method for efficiently learning a collection (i.e., a forest) of generalized decision trees, each with other classification algorithms cascaded to a particular depth, also has been developed In this article, we propose several new strategies, including elitist and ensemble (weighted or unweighted), for using the various decision trees in such a collection in the prediction phase. Our empirical evaluation using 32 data sets in the UCI machine learning repository shows that, on average, the elitist strategy outperforms the weighted full ensemble strategy, which, in turn, outperforms the unweighted full ensemble strategy. However no strategy is universally superior across all applications. Since the same training process can be used to evaluate the various strategies, we recommend that several promising strategies be evaluated and compared before selecting the one to use for a given application.","Title: Collaborative conceptual schema design: a process model and prototype system\nYear: 1998\n\nAbstract: Recent years have seen an increased interest in providing support for collaborative activities among groups of users participating in various information systems design tasks such as, requirements determination and process modeling. However, little attention has been paid to the collaborative conceptual database design process. In this article, we develop a model of the collaborative conceptual schema development process and describe the design and implementation of a graphical multiuser conceptual schema design tool that is based on the model. The system we describe allows a group of users to work collaboratively on the creation of database schemas in synchronous (same-time) mode (either in a face-to-face or distributed setting). Extensive modeling support is provided to assist users in creating semantically correct conceptual schemas. The system also provides users with several graphical facilities such as, a large drawing workspace with the ability to scroll or “jump” to any portion of this workspace, zooming capabilities, and the ability to move object(s) to any portion of the workspace. The unique component of the system, however, is its built-in support for collaborative schema design. The system supports a relaxed WYSIWIS environment, i.e., each user can control the graphical layout of the same set of schema objects. The system ensures that changes/additions made by any user are consistent. Any conflicts that may compromise to the integrity of the shared schema are flagged and resolved by the system. The results from a preliminary experiment suggest that the use of our system in a collaborative mode improved information sharing among users, minimized conflicts, and led to a more comprehensive schema definition.","Title: Transaction management mechanisms for active and real-time databases: a comprehensive protocol and a performance study\nYear: 1998\n\nAbstract: Active and real-time databases (ARTDB) have a variety of applications in electronic brokerages in financial markets, stock trading, network management and manufacturing process control. Transaction processing (TP) in ARTDB is extremely complicated since transactions may trigger other real-time transactions to an arbitrary depth with various types of dependencies (coupling modes). Therefore, transaction processing must be cognizant of not only the time deadlines but also the types of semantic dependencies with other transactions. The conflict resolution between two transactions cannot be considered in isolation since affecting one transaction may affect every other semantically dependent transaction. Similarly, transaction scheduling needs to be compatible with the concurrency control to avoid unnecessary restarts. In this paper we argue that transaction pre-analysis using the pre-declaration paradigm is an efficient mechanism to integrate the various issues of transaction processing such as concurrency control, scheduling, and semantic dependencies. The pre-analysis is possible since in many applications transactions repeat from a set of transaction classes, and the conflicts can be easily determined at a logical level by partitioning relations into mutually exclusive subset (e.g., by stock-id in financial applications). We develop a pre-analysis based transaction processing mechanism called OCCWB. OCCWB is an extended optimistic concurrency control protocol with blocking that combines the benefits of both optimistic and lock based protocols. Such an approach also has an implicit overload management mechanism required in many applications. OCCWB consists of four phases, namely, transaction pre-analysis, serialization ordering, priority adjustment and priority wait. Our protocol is validated using simulation and is shown to outperform existing protocols under various workload and parameter settings.","Title: Integrity constraint integration in heterogeneous databases: an enhanced methodology for schema integration\nYear: 1997\n\nAbstract: In today's technologically diverse corporate environment, it is common to find several different databases being used to accomplish the organization's operational data management functions. Providing interoperability among these databases is important to the successful operation of the organization. One approach to providing interoperability among heterogeneous database systems, is to define one or more schemas which represent a coherent view of the underlying databases. In the past, most approaches have used schematic knowledge about the underlying databases to generate integrated representations of the databases. In this paper we present a seven step methodology for utilizing integrity constraint knowledge from heterogeneous databases. Specifically, we describe how we can generate a set of integrity constraints applicable at the integrated level from constraints specified on local databases. We introduce the concept of constraint-based relationships between objects in heterogeneous databases and describe the role that these relationships play in integrity constraint integration. Finally, we describe how the integrated set of constraints generated using our methodology can be used to facilitate semantic query processing in a heterogeneous database environment.","Title: An Agent-Based Approach For Sourcing Business Rules In Supply Chain Management\nYear: 2005\n\nAbstract: In recent years, business rule management has become an important component of enterprise information systems. Business rules represent guidelines about how an enterprise should conduct its business and provide better service for customers. Business rules are being widely deployed in supply chains to support real-time decision making. The research reported in this paper is aimed at designing a dynamically adaptable data-sourcing service for deploying business rules effectively in supply chain management. Such a data-sourcing service is important since execution of business rules requires data to be retrieved from various data sources spread across the enterprise, including the enterprise data warehouse. We propose a semantics-based approach to implement the data-sourcing service for business rules. Our approach captures semantics of business rules and provides an agent-enabled mechanism that dynamically maps business rules to the enterprise data model. A prototype system is implemented to illustrate our sourcing service and demonstrate the feasibility of our approach.","Title: Supporting User-Defined Granularities in a Spatiotemporal Conceptual Model\nYear: 2002\n\nAbstract: Granularities are integral to spatial and temporal data. A large number of applications require storage of facts along with their temporal and spatial context, which needs to be expressed in terms of appropriate granularities. For many real-world applications, a single granularity in the database is insufficient. In order to support any type of spatial or temporal reasoning, the semantics related to granularities needs to be embedded in the database. Specifying granularities related to facts is an important part of conceptual database design because under-specifying the granularity can restrict an application, affect the relative ordering of events and impact the topological relationships. Closely related to granularities is indeterminacy, i.e., an occurrence time or location associated with a fact that is not known exactly. In this paper, we present an ontology for spatial granularities that is a natural analog of temporal granularities. We propose an upward-compatible, annotation-based spatiotemporal conceptual model that can comprehensively capture the semantics related to spatial and temporal granularities, and indeterminacy without requiring new spatiotemporal constructs. We specify the formal semantics of this spatiotemporal conceptual model via translation to a conventional conceptual model. To underscore the practical focus of our approach, we describe an on-going case study. We apply our approach to a hydrogeologic application at the United States Geologic Survey and demonstrate that our proposed granularity-based spatiotemporal conceptual model is straightforward to use and is comprehensive.","Title: Clustering Schema Elements for Semantic Integration of Heterogeneous Data Sources\nYear: 2004\n\nAbstract: Interschema relationship identification (IRI), that is, determining the relationships among schema elements in heterogeneous data sources, is an important step in integrating the data sources. This article proposes a cluster analysis based approach to semi-automating the IRI process, which is typically very time-consuming and requires extensive human interaction. The authors apply multiple clustering techniques, including K-means, hierarchical clustering, and self-organizing map (SOM) neural network, to identify similar schema elements from heterogeneous data sources, based on a combination of features such as naming similarity, document similarity, schema specification, data patterns, and usage patterns. An SOM prototype the authors have developed provides users with a visualization tool for display of clustering results as well as for incremental evaluation of candidate similar elements.","Title: Predicting Asthma-Related Emergency Department Visits Using Big Data.\nYear: 2015\n\nAbstract: Asthma is one of the most prevalent and costly chronic conditions in the United States which cannot be cured. However accurate and timely surveillance data could allow for timely and targeted interventions at the community or individual level. Current national asthma disease surveillance systems can have data availability lags of up to two weeks. Rapid progress has been made in gathering non-traditional, digital information to perform disease surveillance. We introduce a novel method of using multiple data sources for predicting the number of asthma related emergency department (ED) visits in a specific area. Twitter data, Google search interests and environmental sensor data were collected for this purpose. Our preliminary findings show that our model can predict the number of asthma ED visits based on near-real-time environmental and social media data with approximately 70% precision. The results can be helpful for public health surveillance, emergency department preparedness, and, targeted patient interventions.","Title: Empirical analysis of implicit brand networks on social media\nYear: 2014\n\nAbstract: This paper investigates characteristics of implicit brand networks extracted from a large dataset of user historical activities on a social media platform. To our knowledge, this is one of the first studies to comprehensively examine brands by incorporating user-generated social content and information about user interactions. This paper makes several important contributions. We build and normalize a weighted, undirected network representing interactions among users and brands. We then explore the structure of this network using modified network measures to understand its characteristics and implications. As a part of this exploration, we address three important research questions: (1) What is the structure of a brand-brand network? (2) Does an influential brand have a large number of fans? (3) Does an influential brand receive more positive or more negative comments from social users? Experiments conducted with Facebook data show that the influence of a brand has (a) high positive correlation with the size of a brand, meaning that an influential brand can attract more fans, and, (b) low negative correlation with the sentiment of comments made by users on that brand, which means that negative comments have a more powerful ability to generate awareness of a brand than positive comments. To process the large-scale datasets and networks, we implement MapReduce-based algorithms.","Title: Capturing Telic/Atelic Temporal Data Semantics: Generalizing Conventional Conceptual Models\nYear: 2014\n\nAbstract: Time provides context for all our experiences, cognition, and coordinated collective action. Prior research in linguistics, artificial intelligence, and temporal databases suggests the need to differentiate between temporal facts with goal-related semantics (i.e., telic) from those are intrinsically devoid of culmination (i.e., atelic). To differentiate between telic and atelic data semantics in conceptual database design, we propose an annotation-based temporal conceptual model that generalizes the semantics of a conventional conceptual model. Our temporal conceptual design approach involves: 1) capturing \"what\" semantics using a conventional conceptual model; 2) employing annotations to differentiate between telic and atelic data semantics that help capture \"when\" semantics; 3) specifying temporal constraints, specifically nonsequenced semantics, in the temporal data dictionary as metadata. Our proposed approach provides a mechanism to represent telic/atelic temporal semantics using temporal annotations. We also show how these semantics can be formally defined using constructs of the conventional conceptual model and axioms in first-order logic. Via what we refer to as the \"semantics of composition,\" i.e., semantics implied by the interaction of annotations, we illustrate the logical consequences of representing telic/atelic data semantics during temporal conceptual design.","Title: Screening financial innovations: an expert system approach\nYear: 1990\n\nAbstract: An expert system, called Innovator, that helps a financial-service organization (FSO) evaluate new products it does not currently offer is described. Innovator was implemented using a rule-based expert system shell called Expert System Environment. The authors examine why FSOs need expert systems for screening financial innovations. The knowledge-representation and implementation details, and the system validation process are described. Innovator's benefits and continuing research are discussed.<>","Title: RT @News: An Analysis of News Agency Ego Networks in a Microblogging Environment.\nYear: 2015\n\nAbstract: News agencies regularly use Twitter to publicize and increase readership of their articles. Although substantial research on the spread of news on Twitter exists, there hasn't been much focus on the study of the spread of news articles. In this study, we present an innovative methodology involving weighted ego networks to understand how news agencies propagate news articles using their Twitter handle. We propose a set of measures to compare the propagation process of different news agencies by studying important aspects such as volume, extent of spread, conversion rate, multiplier effect, lifespan, hourly response, and audience participation. Using a dataset of tweets collected over a period of 6 months, we apply our methodology and suggest a framework to help news agencies gauge their performance on social media and also provide critical insights into the phenomenon of news article propagation on Twitter.","Title: Predicting Location-Based Sequential Purchasing Events by Using Spatial, Temporal, and Social Patterns\nYear: 2015\n\nAbstract: Location-based sequential event prediction is an interesting problem with many real-world applications. For example, knowing when and where people will use certain kinds of services could enable the development of robust anticipatory systems. A key to this problem is in understanding the nature of the process from which sequential data arises. Usually, human behavior exhibits distinct spatial, temporal, and social patterns. The authors examine three kinds of patterns extracted from sequential purchasing events and propose a novel model that captures contextual dependencies in spatial sequence, customers' temporal preferences, and social influence via an implicit network. Their model outperforms existing models based on evaluations using a real-world dataset of smartcard transaction records from a large educational institution with 13,753 students during a 10-month time period.","Title: Extracting Signals from Social Media for Chronic Disease Surveillance.\nYear: 2016\n\nAbstract: Asthma is a chronic disease that affects people of all ages, and is a serious health and economic concern worldwide. However, accurate and timely surveillance and predicting hospital visits could allow for targeted interventions and reduce the societal burden of asthma. Current national asthma disease surveillance systems can have data availability lags of up to months and years. Rapid progress has been made in gathering social media data to perform disease surveillance and prediction. We introduce novel methods for extracting signals from social media data to assist in accurate and timely asthma surveillance. Our empirical analyses show that our methods are very effective for surveillance of asthma prevalence at both state and municipal levels. They are also useful for predicting the number of hospital visits based on near-real-time social media data for specific geographic areas. Our results can be used for public health surveillance, ED preparedness, and targeted patient interventions.","Title: Feature Importance and Predictive Modeling for Multi-source Healthcare Data with Missing Values.\nYear: 2016\n\nAbstract: With rapid development of sensor technologies and the internet of things, research in the area of connected health is increasing in importance and complexity with wide-reaching impacts for public health. As data sources such as mobile (wearable) sensors get cheaper, smaller, and smarter, important research questions can be answered by combining information from multiple data sources. However, integration of multiple heterogeneous data streams often results in a dataset with several empty cells or missing values. The challenge is to use such sparsely populated integrated datasets without compromising model performance. Naïve approaches for dataset modification such as discarding observations or ad-hoc replacement of missing values often lead to misleading results. In this paper, we discuss and evaluate current best-practices for modeling such data with missing values and then propose an ensemble-learning based sparse-data modeling framework. We develop a predictive model using this framework and compare it with existing models using a study in a healthcare setting. Instead of generating a single score on variable/feature importance, our framework enables the user to understand the importance of a variable based on the existing data values and their localized impact on the outcome.","Title: SMARTBUS: A Web Application for Smart Urban Mobility and Transportation.\nYear: 2016\n\nAbstract: Systematic evaluation is crucial to the management and development of smart urban transportation, as it allows transportation planners to better understand the impact of their decisions and design targeted interventions to improve efficiency. Implementation of smart and adaptable public transportation is an important challenge in developing cities and newly industrialized economies where growth characteristics contribute to and can be impacted by factors like overcrowding and travel delays. In this paper, we focus on bus transportation, and present the design and implementation of a 3-layer web-based system for performance evaluation and decision support. This is part of a \"Smart Cities\" initiative, which is an international collaboration between academia and government. The first layer estimates fundamental indicators such as bus travel time and passenger demands by integrating heterogeneous data sources. A novel bus-stop network is then designed in the second layer, which enables the derivation of passenger patterns in public transit using network analysis. The third layer provides decision support by analyzing causal relationships between indicators. The proposed web-based system called SMARTBUS is being developed and validated with the city of Fortaleza in Brazil. We believe the use of generally available urban transportation data makes our methodology adaptable and customizable for other cities.","Title: Understanding the Competitive Landscape of News Providers on Social Media.\nYear: 2016\n\nAbstract: Social media has emerged as a mechanism for online news propagation. This in turn has changed the competitive landscape of news providers, a landscape that was previously partitioned based on the traditional channels of news dispersion. The channels of news distribution refer to - television, newspaper, magazine, radio, news agency and online only. In this paper, we examine similarities and differences in news propagation patterns on social media based on the primary channel of a news provider. We collected news article propagation activity data from Twitter for 32 news providers over a three-week period and analyzed their propagation networks. Our analysis shows that the structural properties of the propagation networks are statistically different based on the type of primary channel. Our study has useful implications for understanding the competition between news providers in an online environment.","Title: Smartbike: Policy Making And Decision Support For Bike Share Systems\nYear: 2016\n\nAbstract: Bike share systems have been implemented in many cities to provide an alternative low-cost environmentally friendly and healthy public transportation. Citizens can pick up and drop off bikes among stations around the city. The system may be used for both work-related and leisure purposes including supporting last-mile transportation and tourism. In order to sustain and attract more users into the bike system, understanding demand and trip patterns is a key objective. Further, due to the asymmetric and dynamic nature of user demands, some stations tend to run out of bikes whereas other stations tend to be full ( impeding returns). Rebalancing stations to provide high quality services to fit pick up and drop off demand is a major challenge in bike share systems. In this paper, we present a three-layer SMARTBIKE system to assist city administrators in Fortaleza, Brazil with bike share system decision making. This is an international cooperative effort between academia and government to aid in building a Smart City. The first layer of the proposed tool includes k-means clustering technology to understand the true demand of the city bike share system. We designed a novel station network analysis in the second layer to provide insights on system usage patterns and to help with the rebalancing strategy. The third layer provides rebalancing support at the facility and operation level. Finally, we discuss a dynamic visualization tool to support decision making.","Title: A Big Data Approach For Smart Transportation Management On Bus Network\nYear: 2016\n\nAbstract: Urbanization in developing countries has resulted in increased demand for public transportation in the face of limited resources. This requires smart transportation management that allows urban planners to evaluate the impact of their policies and design targeted interventions. This paper proposes a three-layer management system to support smart urban mobility with an emphasis on bus transportation. In Layer-1, we apply novel Big Data techniques to compute bus travel time and passenger demands in an efficient and economical way. Layer-2 contains two analytic components: network analysis of passenger transit patterns and causal relationship analysis for bus delays. The third layer provides decision support in an interactive visualization environment. The proposed system is developed and validated in cooperation with the city of Fortaleza in Brazil. The use of generally available urban transportation data makes our methodology adaptable and customizable for other cities.","Title: Large-Scale Network Analysis for Online Social Brand Advertising.\nYear: 2016\n\nAbstract: This paper proposes an audience selection framework for online brand advertising based on user activities on social media platforms. It is one of the first studies to our knowledge that develops and analyzes implicit brand-brand networks for online brand advertising. This paper makes several contributions. We first extract and analyze implicit weighted brand-brand networks, representing interactions among users and brands, from a large dataset. We examine network properties and community structures and propose a framework combining text and network analyses to find target audiences. As a part of this framework, we develop a hierarchical community detection algorithm to identify a set of brands that are closely related to a specific brand. This latter brand is referred to as the \"focal brand.\" We also develop a global ranking algorithm to calculate brand influence and select influential brands from this set of closely related brands. This is then combined with sentiment analysis to identify target users from these selected brands. To process large-scale datasets and networks, we implement several MapReduce-based algorithms. Finally, we design a novel evaluation technique to test the effectiveness of our targeting framework. Experiments conducted with Facebook data show that our framework provides significant performance improvements in identifying target audiences for focal brands.","Title: A Regularization Approach for Identifying Cumulative Lagged Effects in Smart Health Applications.\nYear: 2017\n\nAbstract: Recent development of wearable sensor technologies have made it possible to capture concurrent data streams for ambient environment and instantaneous physiological stress response at a fine granularity. Characterizing the delay in physiological stress response time to each environment stimulus is as important as capturing the magnitude of the effect. In this paper, we discuss and evaluate a new regularization-based statistical method to determine the ideal lagged effect of five environmental factors-carbon dioxide, temperature, relative humidity, atmospheric pressure and noise levels on instantaneous stress response. Using this method, we infer that the first four environment variables have a cumulative lagged effect, of approximately 60 minutes, on stress response whereas noise level has an instantaneous effect on stress response. The proposed transformations to inputs result in models with better fit and predictive performance. This study not only informs the field of environment-wellbeing research about the cumulative lagged effects of the specified environmental factors, but also proposes a new method for determining optimal feature transformation in similar smart health studies.","Title: Improving the Domain Independence of Data Provenance Ontologies: A Demonstration Using Conceptual Graphs and the W7 Model\nYear: 2017\n\nAbstract: AbstractProvenance is becoming increasingly important as more and more people are using data that they themselves did not generate. In the last decade, significant efforts have been directed toward developing generic, shared data provenance ontologies that support the interoperability of provenance across systems. An issue that is impeding the use of such provenance ontologies is that a generic provenance ontology, no matter how complete it is, is insufficient for capturing the diverse, complex provenance requirements in different domains. In this paper, the authors propose a novel approach to adapting and extending the W7 model, a well-known generic ontology of data provenance. Relying on various knowledge expansion mechanisms provided by the Conceptual Graph formalism, the authors' approach enables us to develop domain ontologies of provenance in a disciplined yet flexible way.","Title: Predicting interpurchase time in a retail environment using customer-product networks: An empirical study and evaluation.\nYear: 2018\n\nAbstract: •We leverage similarities in customer purchases for product attrition prediction.•We extract an extensive feature set from customer-product graphs.•We boost predictive performance by 6% and product identification by 20%.•Our model illustrates the importance of transactional data for marketing.•We show the advantage of network-based analytics in offline retail.","Title: Using big data and network analysis to understand Wikipedia article quality.\nYear: 2018\n\nAbstract: The research reported in this paper focuses on the question of why Wikipedia articles are different in quality. Since these articles are developed in an open and social environment, our work investigates if the social capital of contributors plays a role in determining the quality of the articles. We focus on three major types of social capital with respect to teams of contributors working on Wikipedia articles: internal bonding, external bridging and functional diversity. Through a social network analysis of these articles based on a dataset extracted from its edit history, our research finds that all three types of social capital have a significant impact on their quality. In addition, we found that internal bonding interacts positively with external bridging resulting in a multiplier effect on article quality. The findings of our research have implications for developing automated techniques for quality assessment of Wikipedia and also provide insights into improving quality of these articles.","Title: Uncovering the effects of digital movie format availability on physical movie sales.\nYear: 2019\n\nAbstract: The impact of multi-channel technology-enabled digital goods on the sales of the physical counterpart faces uncertainty in the electronic commerce domain. We address the issue empirically by identifying the effect of the availability of digitally-delivered movies on physical DVD movie sales. Unique to our study is our interest in not only purchased digital goods but rented digital goods as well. We construct a robust panel dataset consisting of movie data collected from Amazon and Barnes and Noble on the same day for every movie observed. A key feature of our dataset is the multi-channel availability of digital purchase and digital rental movie formats at Amazon. Our results show that the availability of the digital purchase format does not have a significant effect on DVD sales. Surprisingly, the availability of the digital rental format is associated with a significant reduction in DVD sales. The results imply that a product substitution effect may be occurring between the digital rental and the physical DVD purchase of the same movie. We conduct robustness tests to show under which conditions the effect is greatest. Our results also provide practical implications to inform strategies regarding movie format release windows.","Title: When entities are types: effectively modeling type-instantiation relationships\nYear: 2010\n\nAbstract: Type-instantiation relationships (TIRs) appear in many application domains including RFID-based inventory tracking, securities markets, health care, incident-response management, travel, advertising, and academia. For example an emergency response (type) is instantiated in the actual incident, or an advertisement (type) serves impressions on a website. This kind of relationship has received little attention in literature notwithstanding its ubiquity. Conventional modeling does not properly capture its underlying semantics. This can lead to data redundancy, denormalized relations and loss of knowledge about constraints during implementation. Our work formally defines and discusses the semantics of the type-instantiation relationship. We also present an analysis of how TIRs affect other relationships in a conceptual database schema, and the relational implications of our approach.","Title: Digital Libraries for the Next Millennium: Challenges and Research Directions\nYear: 1999\n\nAbstract: The unprecedented growth of Internet technologies has made resources on the World Wide Web instantly accessible to various user communities through digital libraries. Since the early 1990s, there have been several digital library initiatives sponsored by government agencies and/or private organizations all over the world. A digital library is a networked system environment that provides diverse user communities with coherent, seamless and transparent access to large, organized, and digitized information resources. This article provides a comprehensive overview of major digital library projects that are currently being undertaken across the globe. We also identify and discuss major challenges and research issues to be addressed in the design and implementation of digital libraries for the next millennium. We believe that digital libraries are ripe with research opportunities, offer many challenges, and will continue to grow in the next several years.","Title: Understanding Semantic Completeness in Rule Frameworks for Modeling Cardinality Constraints.\nYear: 2018\n\nAbstract: Modeling organizational rules during conceptual design provides a more accurate picture of the underlying domain and helps enforce data integrity. In a database development context, there are many advantages to explicitly representing rules during conceptual design. Early modeling ensures they are visible to designers and users, thus improving requirements and validation. The rules can then be semi-automatically translated into logical design code. One limitation to widespread adoption of such modeling is variance in standards and semantics of rules. We consider cardinality constraints-a useful and integral part of conceptual database design. Many papers discussing classification frameworks for cardinality exist. Completeness of such schemes has always been in question since well-defined criteria do not exist to evaluate them. We suggest a \"reverse engineering\" approach, i.e., one of defining conceptual modeling constraint completeness based on mappings from the relational model. We develop a correspondence from relational algebra operator combinations to existing semantic constraint types. In doing so, we also come up with a new category of set-level cardinality constraints not previously examined in literature. We believe our work demonstrates a unique approach to establishing conceptual framework completeness and enables standardization of rule semantics which in turn allows for semantics-based (as opposed to procedural-based) representation. On the implementation side, it supports developing automated mechanisms for translating constraints to improve developer productivity.","Title: Evaluating Distributed Computing Infrastructures: An Empirical Study Comparing Hadoop Deployments on Cloud and Local Systems\nYear: 2021\n\nAbstract: The popularity of distributed computing platforms (e.g., Hadoop) is largely due to their ability to address scalability issues that arise from data storage and processing limitations of standard computing systems. However, the decision to dedicate organizational resources and capital for such systems needs a careful consideration of several factors including evaluation of cloud-based distributed c...","Title: Finding A Needle In The Haystack: Recommending Online Communities On Social Media Platforms Using Network And Design Science\nYear: 2021\n\nAbstract: We address the problem of recommending online communities on social media platforms using design science. Our method is grounded in network science and leverages the random surfer model of the web, small-world networks, strength of weak connections, and connectivity to analyze three types of large-scale networks. In doing so, we design features for structural hole assortativity and local clustering coefficient rank to capture both the diversity and evolution of user interests. We also extract general online community features such as size and overlap. Experiments conducted on a large dataset of 34,000 lists created and subscribed to by 1,600 active Twitter users over a six-month period showed that our network features outperform the general and content features in terms of recommending communities at the top position. In addition, a combination of general and network features generated the best results in the top position with a significant performance improvement over using only the content features. A combination of all three types of features gave the best results in the top-5 and top-10 positions while improving the quality of recommendations at every other position. Our work outperforms the latest work on community recommendations on social media platforms and has major implications for the design of online community recommenders.","Title: Artifiicial Intelligence in Information Systems: State of the Art and Research Roadmap\nYear: 2022\n\nAbstract: Many would argue that artificial intelligence (AI) is not only technology but also a paradigmatic shift in the relationship between humans and machines. Much literature assumes that AI-powered practices substantially differ from and profoundly change organizational structures, communication, affordances, and ecosystems. However, AI research remains fragmented and often lacks clarity. While the information systems (IS) discipline can play a pivotal role in AI's emergence and use, the discipline needs a clear direction that specifies how it can contribute and its key research themes and questions. This paper draws on a professional development workshop that we organized at the 2020 International Conference on Information Systems and the discussions that followed. We summarize and synthesize how AI has impacted organizational practices over five decades and provide views from various perspectives. We identify weaknesses in the current AI literature as measured against conceptual clarity, theoretical glue, cumulative tradition, parsimony, and applicability. We also identify direct actions that the IS research community can undertake to address these issues. Finally, we propose a next-step research agenda to guide AI research in the coming years.","Title: Deep Learning of Spatiotemporal Patterns for Urban Mobility Prediction Using Big Data\nYear: 2022\n\nAbstract: Timely and accurate prediction of human movement in urban areas offers instructive insights into transportation management, public safety, and location-based services, to name a few. Yet, modeling urban mobility is challenging and complex because of the spatiotemporal dynamics of movement behavior and the influence of exogenous factors such as weather, holidays, and local events. In this paper, we use bus transportation as a proxy to mine spatiotemporal travel patterns. We propose a deep-learning-based urban mobility prediction model that collectively forecasts passenger flows between pairs of city regions in an origin-destination (OD) matrix. We first process OD matrices in a convolutional neural network to capture spatial correlations. Intermediate results are reconstructed into three multivariate time series: hourly, daily, and weekly time series. Each time series is aggregated in a long short-term memory (LSTM) network with a novel attention mechanism to guide the aggregation. In addition, our model is context-aware by using contextual embeddings learned from exogenous factors. We dynamically merge results from LSTM components and context embeddings in a late fusion network to make a final prediction. The proposed model is implemented and evaluated using a large-scale transportation data set of more than 200 million bus trips with a suite of Big Data technologies developed for data processing. Through performance comparison, we show that our approach achieves sizable accuracy improvements in urban mobility prediction. Our work has major implications for efficient transportation system design and performance improvement. The proposed deep neural network structure is generally applicable for sequential graph data prediction."],"string":"[\n \"Title: Linking Biological Databases Semantically for Knowledge Discovery\\nYear: 2008\\n\\nAbstract: Many important life sciences questions are aimed at studying the relationships and interactions between biological functions/processes and biological entities such as genes. The answers may be found by examining diverse types of biological/genomic databases. Finding these answers, however, requires accessing, and retrieving data, from diverse biological data sources. More importantly, sophisticated knowledge discovery processes involve traversing through large numbers of inherent links among various data sources. Currently, the links among data are either implemented as hyperlinks without explicitly indicating their meanings and labels, or hidden in a seemingly simple text format. Consequently, biologists spend numerous hours identifying potentially useful links and following each lead manually, which is time-consuming and error-prone. Our research is aimed at constructing semantic relationships among all biological entities. We have designed a semantic model to categorize and formally define the links. By incorporating ontologies such as Gene or Sequence ontology, we propose techniques to analyze the links embedded within and among data records, to explicitly label their semantics, and to facilitate link traversal, querying, and data sharing. Users may then ask complicated and ad hoc questions and even design their own workflow to support their knowledge discovery processes. In addition, we have performed an empirical analysis to demonstrate that our method can not only improve the efficiency of querying multiple databases, but also yield more useful information.\",\n \"Title: Semantic Conflict Resolution Ontology (SCROL): An Ontology for Detecting and Resolving Data and Schema-Level Semantic Conflicts\\nYear: 2004\\n\\nAbstract: Abstract--Establishing semantic interoperability among heterogeneous information sources has been a critical issue in the database community for the past two decades. Despite the critical importance, current approaches to semantic interoperability of heterogeneous databases have not been sufficiently effective. We propose a common ontology called Semantic Conflict Resolution Ontology (SCROL) that addresses the inherent difficulties in the conventional approaches, i.e., federated schema and domain ontology approaches. SCROL provides a systematic method for automatically detecting and resolving various semantic conflicts in heterogeneous databases. SCROL provides a dynamic mechanism of comparing and manipulating contextual knowledge of each information source, which is useful in achieving semantic interoperability among heterogeneous databases. We show how SCROL is used for detecting and resolving semantic conflicts between semantically equivalent schema and data elements. In addition, we present evaluation results to show that SCROL can be successfully used to automate the process of identifying and resolving semantic conflicts.\",\n \"Title: A comprehensive framework for modeling set-based business rules during conceptual database design\\nYear: 2005\\n\\nAbstract: Business rules are the basis of any organization. From an information systems perspective, these business rules function as constraints on a database helping ensure that the structure and content of the real world sometimes referred to as miniworld--is accurately incorporated into the database. It is important to elicit these rules during the analysis and design stage, since the captured rules are the basis for subsequent development of a business constraints repository. We present a taxonomy for set-based business rules, and describe an overarching framework for modeling rules that constrain the cardinality of sets. The proposed framework results in various types constraints, i.e.. attribute, class, participation, projection, co-occurrence, appearance and overlappinq, on a semantic model that supports abstractions like classification, generalization/specialization, aggregation and association. We formally define the syntax of our proposed framework in Backus-Naur Form and explicate the semantics using first-order logic. We describe partial ordering in the constraints and define the concept of metaconstraints, which can be used for automatic constraint consistency checking during the design stage itself. We demonstrate the practicality of our approach with a case study and show how our approach to modeling business rules seamlessly integrates into existing database design methodology. Via our proposed framework, we show how explicitly capturing data semantics will help bridge the semantic gap between the real world and its representation in an information system.\",\n \"Title: Intelligent database design using the unifying semantic model\\nYear: 1995\\n\\nAbstract: Research and development in the field of database systems has culminated in its widespread use. As usage has grown, the desire to link separate databases has resulted in substantial effort being directed towards the design of distributed database systems. A major research issue in designing such systems is the definition of a formal model that can be used to capture the semantics of the individual databases. This paper presents a semantic model called the Unifying Semantic Model (USM) and a software tool using it. The USM can be used for modeling the complex interrelationships and semantics found in a manufacturing environment. It is based on enhancements to existing semantic models. It can serve as a formal specification and documentation tool for databases. It can provide a means of specifying the Universe of Discourse for any interchange of information.\",\n \"Title: Entity identification for heterogeneous database integration: a multiple classifier system approach and empirical evaluation\\nYear: 2005\\n\\nAbstract: Entity identification, i.e., detecting semantically corresponding records from heterogeneous data sources, is a critical step in integrating the data sources. The objective of this research is to develop and evaluate a novel multiple classifier system approach that improves entity identification accuracy. We apply various classification techniques drawn from statistical pattern recognition, machine learning, and artificial neural networks to determine whether two records from different data sources represent the same real-world entity. We further employ a variety of ways to combine multiple classifiers for improved classification accuracy. In this paper, we report on some promising empirical results that demonstrate performance improvement by combining multiple classifiers.\",\n \"Title: HyperIntelligence: the next frontier\\nYear: 1990\\n\\nAbstract: The authors discuss how mental models may be used to organize an individual's thoughts while forming a plan. A hypermedia system, SPRINT, is described which supports an explicit representation of a mental model as a network of associations among the elements of a strategic plan.\",\n \"Title: Understanding database design expertise\\nYear: 1995\\n\\nAbstract: Database design is a complex and time-consuming process. In order to automate database design, an understanding of the nature of expertise that goes into the design process is needed. Although a number of expert systems have been developed to assist or replace a database designer, database design expertise has not been examined in any detail, This paper proposes a conceptual framework for explaining this type of expertise. The components of the framework are applied to each phase of the design process and used to provide guidelines for the level of expertise developers might strive to obtain. Several representative systems are analyzed, based on the framework, to explore the degree to which expertise is being captured. Implications for the future development of database design expert systems are discussed.\",\n \"Title: Provenance Management in BioSciences\\nYear: 2010\\n\\nAbstract: Data provenance is becoming increasingly important for biosciences with the advent of large-scale collaborative environments\\n such as the iPlant collaborative, where scientists collaborate by using data that they themselves did not generate. To facilitate\\n the widespread use and sharing of provenance, ontologies of provenance need to be developed to enable the capture and standardized\\n representation of provenance for biosciences. Working with researchers from the iPlant Tree of Life (iPToL) Grand Challenge\\n Project, we developed a domain ontology of provenance for phylogenetic analysis. Relying on the conceptual graph formalism,\\n we describe the process of developing the provenance ontology based on the W7 model, a generic ontology of data provenance.\\n This domain ontology provides a structured model for harvesting, storing and querying provenance. We also illustrate how the\\n harvested data provenance based on our ontology can be used for different purposes.\",\n \"Title: Database design and querying within the fuzzy semantic model\\nYear: 2007\\n\\nAbstract: Fuzzy semantic model (FSM) is a data model that uses basic concepts of semantic modeling and supports handling fuzziness, uncertainty and imprecision of real-world at the attribute, entity and class levels. The paper presents the principles and constructs of the FSM. It proposes ways to define the membership functions within all the constructs of the FSM. In addition, it provides a proposal for specifying FSM schema and introduce a query language adapted to FSM-based databases.\",\n \"Title: Augmenting a Conceptual Model with Geospatiotemporal Annotations\\nYear: 2004\\n\\nAbstract: While many real-world applications need to organize data based on space (e.g., geology, geomarketing, environmental modeling) and/or time (e.g., accounting, inventory management, personnel management), existing conventional conceptual models do not provide a straightforward mechanism to explicitly capture the associated spatial and temporal semantics. As a result, it is left to database designers to discover, design, and implement驴on an ad hoc basis驴the temporal and spatial concepts that they need. We propose an annotation-based approach that allows a database designer to focus first on nontemporal and nongeospatial aspects (i.e., \\\"what驴) of the application and, subsequently, augment the conceptual schema with geospatiotemporal annotations (i.e., \\\"when驴 and \\\"where驴). Via annotations, we enable a supplementary level of abstraction that succinctly encapsulates the geospatiotemporal data semantics and naturally extends the semantics of a conventional conceptual model. An overarching assumption in conceptual modeling has always been that expressiveness and formality need to be balanced with simplicity. We posit that our formally defined annotation-based approach is not only expressive, but also straightforward to understand and implement.\",\n \"Title: An architecture for distributed knowledge based-systems\\nYear: 1991\\n\\nAbstract: Many management information systems have requirements that are inherently distributed, both logically and physically, however, no adequate architectures exist which allow multiple knowledge bases and databases to be shared and integrated. An architecture for Distributed Knowledge-Based Systems (DKBS) is presented which satisfies these requirements. A Distributed Knowledge Base Management System (DKBMS) is described which manages the meta-knowledge necessary to coordinate multiple local Knowledge-Based Systems (KBSs). We propose an object-oriented design for implementing the DKBMS structure and the communication protocol which connects the DKBMS with each of the KBSs. An application is described where the DKBS architecture might assist managers to integrate several KBSs which represent parts of a strategic plan.\",\n \"Title: Panel: new directions for conceptual modeling\\nYear: 2011\\n\\nAbstract: This panel examines potential opportunities for conceptual modeling research in new domains.\",\n \"Title: Resource Discovery and Intelligent Image Retrieval in a Distributed Environment\\nYear: 1997\\n\\nAbstract: Remote sensing satellites are generating largeamounts of (image) data at different levels oftemporal, spatial and spectral resolution, with varyinglevels of detail, and at various stages of processingwith a variety of algorithms. This bewildering arrayof data sources is going to mandate a new class ofinformation retrieval systems to help end-users accessthe networked information resources effectively. Inthis paper, we propose intelligent agent basedmechanisms to locate the appropriate sources ofsatellite data, processing algorithms, and ancillarydata that may be required at various levels ofprocessing to answer different types of temporal andspatial queries.\",\n \"Title: Integrating information systems technologies to support consultation in an information center\\nYear: 1992\\n\\nAbstract: This paper presents an approach for integrating different types of information systems technologies to support the functions of an information center (IC). A knowledge-based system, information center expert/help service (ICE/H), has been developed to provide support for the help services of an IC. A general process model to represent the consultation process in an IC is described. Based on this model, an architecture has been developed to support the consultation process. The architecture depicts the use of a knowledge management system, a data management system and a communication (e-mail) system to emulate the consultation process. The ICE/H system has been implemented using this architecture to support an IC with 5000 users.\",\n \"Title: Semantics-Based Transaction Processing for Real-Time Databases: The Case of Automated Stock Trading\\nYear: 1999\\n\\nAbstract: <P>In the future, automated stock trading (AST) databases will need to support execution of transactions with time constraints similar to that discussed in real-time databases. Transactions in AST databases repeat from a predictable set of transaction classes where the logical read-sets and write-sets of these classes can be established a priori. We propose a novel transaction management mechanism that exploits this a priori knowledge of data requirements to minimize wasted resources and transaction restarts inherent in existing real-time transaction processing mechanisms based on dynamic acquisition of resources. Preanalysis provides a mechanism to incorporate transaction semantics, identify potentially detrimental conflicts, and induce favorable serialization orders before transactions execute. By blocking potentially conflicting transactions, we incorporate an implicit overload management technique. Scheduling decisions can be made efficient to complement serialization orders, thus reducing unnecessary transaction restarts. Our protocol is evaluated using simulation and is shown to outperform existing real-time concurrency control mechanisms under various workload and resource parameters.</P>\",\n \"Title: On augmenting database design-support environments to capture the geo-spatio-temporal data semantics\\nYear: 2006\\n\\nAbstract: A database design-support environment supports a data analyst in eliciting, articulating, specifying and validating data-related requirements. Extant design-support environments--based on conventional conceptual models--do not adequately support applications that need to organize data based on time (e.g., accounting, portfolio management, personnel management) and/or space (e.g., facility management, transportation, logistics). For geo-spatio-temporal applications, it is left to database designers to discover, design and implement--on an ad-hoc basis--the temporal and geospatial concepts that they need to represent the miniworld. To elicit the geo-spatio-temporal data semantics, we characterize guiding principles for augmenting the conventional conceptual database design approach, present our annotation-based approach, and illustrate how our proposed approach can be instantiated via a proof-of-concept prototype. Via a proof-of-concept database design-support environment, we exemplify our annotation-based approach, and show how segregating \\\"what\\\" from \\\"when/where\\\" via annotations satisfies ontologic- and cognition-based requirements, dovetails with existing database design methodologies, results in upward-compatible conceptual as well as XML schemas, and provides a straightforward mechanism to extend extant design-support environments.\",\n \"Title: Sharing News Articles Using 140 Characters: A Diffusion Analysis on Twitter\\nYear: 2012\\n\\nAbstract: Is it possible to effectively spread news articles to a large audience using 140 characters? How does the microblogging website Twitter get used as a platform for the news media agencies to create awareness about the articles they publish on a daily basis? Our study of the diffusion patterns of news articles from 12 popular news sources, including BBC, New York Times, and Mash able on Twitter reveals that a large number of users not only consume and comment on these news articles but also share them in different ways. Combining the methods of network and temporal analyses, we examine and report on how news articles diffuse on Twitter, and how different propagation mechanisms result in different life spans for news articles.\",\n \"Title: Using a Network Analysis Approach for Organizing Social Bookmarking Tags and Enabling Web Content Discovery\\nYear: 2012\\n\\nAbstract: This article describes an innovative approach to reorganizing the tag space generated by social bookmarking services. The objective of this work is to enable effective search and discovery of Web content using social bookmarking tags. Tags are metadata generated by users for Web content annotation. Their potential as effective Web search and discovery tool is hindered by challenges such as, the tag space being untidy due to ambiguity, and hidden or implicit semantics. Using a novel analytics approach, we conducted network analyses on tags and discovered that tags are generated for different purposes and that there are inherent relationships among tags. Our approach can be used to extract the purposes of tags and relationships among the tags and this information can be used as facets to add structure and hierarchy to reorganize the flat tag space. The semantics of relationships and hierarchy in our proposed faceted model of tags enable searches on annotated Web content in an effective manner. We describe the implementation of a prototype system called FASTS to demonstrate feasibility and effectiveness of our approach.\",\n \"Title: Practical aspects of teaching an applied database course\\nYear: 1996\\n\\nAbstract: The information systems curriculum recommendations proposed by ACM (Nunamaker et al., 1982), IFIP (Buckingham et al., 1987), DPMA (1991), and the recent ACM/AIS/DPMA (Couger et al., 1995, 1997) contain an overlapping core and several electives. Coverage of database concepts is required by all of the three curriculum recommendations for the development of information systems professionals. An important component of this requirement is learning the practical aspects of developing information systems by using databases In this paper we will present our experiences and recommendations in implementing this important aspect of teaching database courses within the information systems curriculum. In particular we will a) discuss management of field projects, including their benefits and pitfalls; and 2) make recommendations on fools and technologies available for implementation within a class room environment.\",\n \"Title: Constrained cascade generalization of decision trees\\nYear: 2004\\n\\nAbstract: While decision tree techniques have been widely used in classification applications, a shortcoming of many decision tree inducers is that they do not learn intermediate concepts, i.e., at each node, only one of the original features is involved in the branching decision. Combining other classification methods, which learn intermediate concepts, with decision tree inducers can produce more flexible decision boundaries that separate different classes, potentially improving classification accuracy. We propose a generic algorithm for cascade generalization of decision tree inducers with the maximum cascading depth as a parameter to constrain the degree of cascading. Cascading methods proposed in the past, i.e., loose coupling and tight coupling, are strictly special cases of this new algorithm. We have empirically evaluated the proposed algorithm using logistic regression and C4.5 as base inducers on 32 UCI data sets and found that neither loose coupling nor tight coupling is always the best cascading strategy and that the maximum cascading depth in the proposed algorithm can be tuned for better classification accuracy. We have also empirically compared the proposed algorithm and ensemble methods such as bagging and boosting and found that the proposed algorithm performs marginally better than bagging and boosting on the average.\",\n \"Title: Communication requirements and network evaluation within electronic meeting system environments\\nYear: 1991\\n\\nAbstract: One of the key issues in the design and implementation of Electronic Meeting Systems (EMS) is the identification of appropriate support for computer commununications. Lack of adequate communication support can create a bottleneck in the use of EMS. Our objective is to identify the communication needs of several different EMS environments and to discuss an approach that can be used to evaluate the required communication support. We then use this approach to benchmark the performance of two Local Area Network (LAN) operating systems (IBM LAN program and Novell Netware) and three network servers (IBM PS/2 models 50, 60 and 80) in one EMS environment. While network operating systems have received comparatively less attention in LAN evaluation and design, fully 75% of the response time in some configurations was due solely to the network operating system. The Novell Netware software running on the IBM PS/2 model 50 server provided at least as great speed at lower cost than any other configuration tested. For the small files common to one style of EMS environment (i.e. under 2.5K), response time was not affected by the size of the file but rather was determined by the fixed overhead imposed by the network operating system.\",\n \"Title: Group data base design: addressing the view modeling problem\\nYear: 1995\\n\\nAbstract: Today's organizations increasingly depend on the use of data base technology to manage their operations. Advances in technology have resulted in increasing the number and complexity of these data bases. Despite their growing complexity, all data bases have one thing in common: each must have gone through either a formal or an informal design process. Data bases must mirror reality accurately, and thus the design process must better capture that reality. The heart of the design process is the conceptual design, data model mapping, and physical design. Our research focuses on providing automated support for the first of these, e.g., conceptual design. Conceptual design is known to be a very difficult and time-consuming phase in the development of data base applications. This article describes the architecture, implementation, and use of a distributed graphical group data base design system. The group view modeling system (GVMS) is implemented in Microsoft Windows for networked personal computers. The main purpose of GVMS is to allow multiple designers (or users) to share conceptual design information in real time and resolve design conflicts through the electronic medium. The underlying data model, semantic data model, is extended to include distribution information as well as transactions and is represented as an extended entity relationship model. Diagram management techniques are implemented to aid in simplifying large complex designs. A small study demonstrated that groups of data base designers who define their view collectively outperform individuals.\",\n \"Title: A Blackboard-Based Cooperative System for Schema Integration\\nYear: 1995\\n\\nAbstract: We describe a four-level blackboard architecture that supports schema integration and provide a detailed description of the communication among human and computational agents that this system allows.Today's corporate information system environments are heterogeneous, consisting of multiple and independently managed databases. Many applications that assist decision making call for access to data from multiple heterogeneous databases. To facilitate this, there needs to be an integrated representation of the underlying databases that allows users to query multiple databases simultaneously. The process of deriving this integrated representation is called schema integration.Schema integration is time consuming and complex, as it requires a thorough understanding of the underlying database semantics. Since no data model can capture the entire real world semantics of each database's objects, this process requires human agent assistance. Although certain aspects of schema integration can be automated, interaction with designers and users is still necessary. In this article, we describe how blackboard architectures can facilitate the communication among human and computational agents for schema integration.\",\n \"Title: Research Commentary: An Agenda for Information Technology Research in Heterogeneous and Distributed Environments\\nYear: 2000\\n\\nAbstract: Application-driven, technology-intensive research is critically needed to meet the challenges of globalization, interactivity, high productivity, and rapid adaptation faced by business organizations. Information systems researchers are uniquely positioned to conduct such research, combining computer science, mathematical modeling, systems thinking, management science, cognitive science, and knowledge of organizations and their functions. We present an agenda for addressing these challenges as they affect organizations in heterogeneous and distributed environments. We focus on three major capabilities enabled by such environments: Mobile Computing, Intelligent Agents, and Net-Centric Computing. We identify and define important unresolved problems in each of these areas and propose research strategies to address them.\",\n \"Title: DISTIL: A Design Support Environment for Conceptual Modeling of Spatio-temporal Requirements\\nYear: 2001\\n\\nAbstract: We describe DISTIL (DIstributed design of SpaTIo-temporaL data), a web-based conceptual modeling prototype system that can help capture the semantics of spatio-temporal data. Via DISTIL, we describe an annotation-based approach that divides spatio-temporal conceptual design into two steps: first capture the current reality of an application using a conventional conceptual model without considering the spatial aspects, and only then annotate the schema with the spatio-temporal semantics of the application. A database development team can use DISTIL to capture and validate their spatio-temporal data requirements. Using DISTIL we demonstrate that the annotation-based approach for capturing spatio-temporal requirements is straightforward to implement, satisfies ontology-based and cognition-based requirements, and integrates seamlessly into the existing database design methodologies.\",\n \"Title: Examining lists on Twitter to uncover relationships between following, membership and subscription\\nYear: 2013\\n\\nAbstract: We report on an exploratory analysis of pairwise relationships between three different forms of information consumption on Twitter viz., following, listing and subscribing. We develop a systematic framework to examine the relationships between these three forms. Using our framework, we conducted an empirical analysis of a dataset from Twitter. Our results show that people not only consume information by explicitly following others, but also by listing and subscribing to lists and that the people they list or subscribe to are not the same as the ones they follow. Our work has implications for understanding information propagation and diffusion via Twitter and for generating recommendations for adding users to lists, subscribing and merging or splitting them.\",\n \"Title: Next-Generation Team-Science Platform for Scientific Collaboration\\nYear: 2011\\n\\nAbstract: Emerging research on team science aims at better understanding the key contextual factors during the trans-disciplinary scientific collaboration process and enhancing the outcomes of large-scale collaborative research programs. Team science can range from a few participants working at the same site to numerous researchers dispersed across multiple geographic and organizational venues. This article outlines the fundamental conceptual framework of a next-generation team-science-enabling platform (TSEP).\",\n \"Title: Advances In Data Modeling Research\\nYear: 2005\\n\\nAbstract: In this paper, we summarize the discussions of the panel on \\\"Advances in Data Modeling Research,\\\" held at the Americas Conference on Information Systems (AMCIS) in 2005. We focus on four primary areas where data modeling research offers rich opportunities: spatio-temporal semantics, genome research, ontological analysis and empirical evaluation of existing models. We highlight past work in each area and also discuss open questions, with a view to promoting future research in the overall data modeling area.\",\n \"Title: Entity matching across heterogeneous data sources: An approach based on constrained cascade generalization\\nYear: 2008\\n\\nAbstract: To integrate or link the data stored in heterogeneous data sources, a critical problem is entity matching, i.e., matching records representing semantically corresponding entities in the real world, across the sources. While decision tree techniques have been used to learn entity matching rules, most decision tree learners have an inherent representational bias, that is, they generate univariate trees and restrict the decision boundaries to be axis-orthogonal hyper-planes in the feature space. Cascading other classification methods with decision tree learners can alleviate this bias and potentially increase classification accuracy. In this paper, the authors apply a recently-developed constrained cascade generalization method in entity matching and report on empirical evaluation using real-world data. The evaluation results show that this method outperforms the base classification methods in terms of classification accuracy, especially in the dirtiest case.\",\n \"Title: Modeling Spatial and Temporal Set-Based Constraints During Conceptual Database Design\\nYear: 2012\\n\\nAbstract: From a database perspective, business constraints provide an accurate picture of the real world being modeled and help enforce data integrity. Typically, rules are gathered during requirements analysis and embedded in code during the implementation phase. We propose that the rules be explicitly modeled during conceptual design, and develop a framework for understanding and classifying spatiotemporal set-based (cardinality) constraints and an associated syntax. The constraint semantics are formally specified using first-order logic. Modeling rules in conceptual design ensures they are visible to designers and users and not buried in application code. The rules can then be semiautomatically translated into logical design triggers yielding productivity gains. Following the principles of design science research, we evaluate the framework's expressiveness and utility with a case study.\",\n \"Title: Multicriterion Market Segmentation: A New Model, Implementation, and Evaluation\\nYear: 2010\\n\\nAbstract: Market segmentation is inherently a multicriterion problem even though it has often been modeled as a single-criterion problem in the traditional marketing literature and in practice. This paper discusses the multicriterion nature of market segmentation and develops a new mathematical model that addresses this issue. A new method for market segmentation based on multiobjective evolutionary algorithms, called MMSEA, is developed. It complements existing segmentation methods by optimizing multiple objectives simultaneously, searching for globally optimal solutions, and approximating a set of Pareto-optimal solutions. We have applied and evaluated this method in two empirical studies for two firms from distinct industries: descriptive segmentation of the cell phone service market from a dual-value creation perspective and predictive segmentation of retail customers based on profit and customer sociodemographic attributes. The results provide decision makers with compelling alternatives and enhanced flexibility currently missing in existing market segmentation methods.\",\n \"Title: Common citation analysis and technology overlap factor: an empirical investigation of litigated patents using network analysis\\nYear: 2012\\n\\nAbstract: Companies incur huge costs in filing and defending patent lawsuits. A part of the problem arises from the fact that companies do not have a comprehensive understanding of the patents that they have cited and the patents that have cited their patents. By empirically analyzing the forward and backward citations of a set of litigated patents in the smart phone industry, we provide a method for profiling patents and identifying citation patterns. Our results show that while some patents share common forward and backward citations, others do not share any backward citations but share a lot of forward citations. We hypothesize that this maybe an indication of the convergence of different types of technologies. We also propose a new metric - Technology Overlap Factor - that can help in identifying convergence. In doing so, we provide a preliminary framework for further investigation and for building a patent analysis software system.\",\n \"Title: A Comprehensive Framework Towards Information Sharing Between Government Agencies\\nYear: 2007\\n\\nAbstract: Recently, there has been increased interest in sharing digitized information between government agencies, with the goals of improving security, reducing costs, and offering better quality service to users of government services. The bulk of previous work in interagency information sharing has focused largely on the sharing of structured information among heterogeneous data sources, whereas government agencies need to share data with varying degrees of structure ranging from free text documents to relational data. In this work, we explore the different technologies available to share information. Specifically, our framework discusses the optional data storage mechanisms required to support a Service Oriented Architecture (SOA). We compare XML document, free text search engine, and relational database technologies and analyze the pros and cons of each approach. We explore these options along the dimensions of information definition, information storage, the access to this information, and finally the maintenance of shared information.\",\n \"Title: GeoCosm: A Semantics-Based Approach for Information Integration of Geospatial Data\\nYear: 2001\\n\\nAbstract: Information integration implies access to distributed information sources without interfering with the autonomy of the underlying\\n data sources. Integration of distributed geospatial data requires a mechanism for selecting the data sources and performing\\n data processing operations on the selected sources efficiently. We describe a semantics-based information integration approach\\n that uses a spatio-temporal semantic model to define the geospatial information content of the sources, employs a conflict\\n resolution ontology to resolve semantic heterogeneity, and uses geospatial metadata to help the users evaluate usefulness\\n of the available data sources. We show how the captured metadata can be used for efficient query planning. Based on our proposed\\n approach, we are developing GeoCosm, a web-based prototype that would help integrate autonomous distributed heterogeneous\\n geospatial data.\",\n \"Title: IAIS: A Methodology to Enable Inter-Agency Information Sharing In eGovernment\\nYear: 2003\\n\\nAbstract: Recently, there has been increased interest in information sharing among government agencies, with a view toward improving security, reducing costs and offering better quality service to users of government services. In this work, the authors complement earlier work by proposing a comprehensive methodology called IAIS (Inter Agency Information Sharing) that uses XML to facilitate the definition of information that needs to be shared, the storage of such information, the access to this information and finally the maintenance of shared information. The authors compare IAIS with two alternate methodologies to share information among agencies, and analyze the pros and cons of each. They also show how IAIS leverages the recently proposed XML (extensible markup language) standard to allow for inclusion of various groups' viewpoints when determining what information should be shared and how it should be structured.\",\n \"Title: Understanding the semantics of data provenance to support active conceptual modeling\\nYear: 2006\\n\\nAbstract: Data Provenance refers to the lineage of data including its origin, key events that occur over the course of its lifecycle, and other details associated with data creation, processing, and archiving. We believe that tracking provenance enables users to share, discover, and reuse the data, thus streamlining collaborative activities, reducing the possibility of repeating dead ends, and facilitating learning. It also provides a mechanism to transition from static to active conceptual modeling. The primary goal of our research is to investigate the semantics or meaning of data provenance. We describe the W7 model that represents different components of provenance and their relationships to each other. We conceptualize provenance as a combination of seven interconnected elements including \\\"what\\\", \\\"when\\\", \\\"where\\\", \\\"how\\\", \\\"who\\\", \\\"which\\\" and \\\"why\\\". Each of these components may be used to track events that affect data during its lifetime. A homeland security example illustrates how current conceptual models can be extended to embed provenance.\",\n \"Title: Semantic-Model Support for Geographic Information Systems\\nYear: 1999\\n\\nAbstract: Natural resource management is an important issue that uses large amounts of spatial and temporal data. It is risky to predict the consequences of resource management decisions without accurately understanding the interaction of ecosystems over a large region.A geographical information system describes objects from the real world in terms oflocation--geographic positions, attributes that are unrelated to position, such as soil type, elevation, and demographics, spatial relationships--how objects are linked, and temporal information--the evolution of both spatial and nonspatial data over time. The authors collaborated on this project to develop a computer environment that enables ecological researchers to analyze and solve problems concerning real ecosystems. Their system brings together and makes accessible data from a variety of heterogeneous databases.Such efforts have a high level of complexity when they seek to produce credible solutions to real-world management concerns. Over the past several years, the term synthetic environment has emerged to describe this type of simulation system.\",\n \"Title: Combining schema and instance information for integrating heterogeneous data sources\\nYear: 2007\\n\\nAbstract: Determining the correspondences among heterogeneous data sources, which is critical to integration of the data sources, is a complex and resource-consuming task that demands automated support. We propose an iterative procedure for detecting both schema-level and instance-level correspondences from heterogeneous data sources. Cluster analysis techniques are used first to identify similar schema elements (i.e., relations and attributes). Based on the identified schema-level correspondences, classification techniques are used to identify matching tuples. Statistical analysis techniques are then applied to a preliminary integrated data set to evaluate the relationships among schema elements more accurately. Improvement in schema-level correspondences triggers another iteration of an iterative procedure. We have performed empirical evaluation using real-world heterogeneous data sources and report in this paper some promising results (i.e., incremental improvement in identified correspondences) that demonstrate the utility of the proposed iterative procedure.\",\n \"Title: Using a knowledge learning framework to predict errors in database design\\nYear: 2014\\n\\nAbstract: Conceptual data modeling is a critical but difficult part of database development. Little research has attempted to find the underlying causes of the cognitive challenges or errors made during this stage. This paper describes a Modeling Expertise Framework (MEF) that uses modeler expertise to predict errors based on the revised Bloom's taxonomy (RBT). The utility of RBT is in providing a classification of cognitive processes that can be applied to knowledge activities such as conceptual modeling. We employ the MEF to map conceptual modeling tasks to different levels of cognitive complexity and classify current modeler expertise levels. An experimental exercise confirms our predictions of errors. Our work provides an understanding into why novices can handle entity classes and identifying binary relationships with some ease, but find other components like ternary relationships difficult. We discuss implications for data modeling training at a novice and intermediate level, which can be extended to other areas of Information Systems education and training.\",\n \"Title: Toward semantic interoperability of heterogeneous biological data sources\\nYear: 2005\\n\\nAbstract: Genomic researchers use a number of heterogeneous data sources including nucleotides, protein sequences, 3-D Protein structures, taxonomies, and research publications such as MEDLINE. This research aims to discover as much biological knowledge as possible about the properties and functions of the structures such as DNA sequences and protein structures and to explore the connections among all the data, so that the knowledge can be used to improve human lives. Currently it is very difficult to connect all of these data sources seamlessly unless all the data is transformed into a common format with an id connecting all of them. The state-of-the-art facilities for searching these data sources provide interfaces through which scientists can access multiple databases. Most of these searches are primarily text based, requiring users to specify keywords using which the systems search through each individual data source and returns results. The user is then required to create the connections between the results from each source. This is a major problem because researchers do not always know how to create these connections. To solve this problem we propose a semantics-based mechanism for automatically linking and connecting the various data sources. Our approach is based on a model that explicitly captures the semantics of the heterogeneous data sources and makes them available for searching. In this talk I will discuss issues related to capturing the semantics of biological data and using these semantics to automate the integration of diverse heterogeneous sources.\",\n \"Title: FASTS: FAcets structured tag space – a novel approach to organize and reuse social bookmarking tags\\nYear: 2010\\n\\nAbstract: Social bookmarking tools are generating an enormous pool of metadata describing and categorizing web resources The value of these metadata in the form of tags can be fully realized only when they are shared and reused for web search and retrieval The research described in this paper proposes a facet classification mechanism, and a tag relationship ontology to organize tags into a meaningful and intuitively useful structure We have implemented a web-based prototype system to effectively search and browse bookmarked web resources using this approach We collected real tag data from del.icio.us for a wide range of popular domains We analyzed, processed, and organized these tags to demonstrate the effectiveness and utility of our approach for tag organization and reuse.\",\n \"Title: Information systems interoperability: What lies beneath?\\nYear: 2004\\n\\nAbstract: Interoperability is the most critical issue facing businesses that need to access information from multiple information systems. Our objective in this research is to develop a comprehensive framework and methodology to facilitate semantic interoperability among distributed and heterogeneous information systems. A comprehensive framework for managing various semantic conflicts is proposed. Our proposed framework provides a unified view of the underlying representational and reasoning formalism for the semantic mediation process. This framework is then used as a basis for automating the detection and resolution of semantic conflicts among heterogeneous information sources. We define several types of semantic mediators to achieve semantic interoperability. A domain-independent ontology is used to capture various semantic conflicts. A mediation-based query processing technique is developed to provide uniform and integrated access to the multiple heterogeneous databases. A usable prototype is implemented as a proof-of-concept for this work. Finally, the usefulness of our approach is evaluated using three cases in different application domains. Various heterogeneous datasets are used during the evaluation phase. The results of the evaluation suggest that correct identification and construction of both schema and ontology-schema mapping knowledge play very important roles in achieving interoperability at both the data and schema levels.\",\n \"Title: Design science in information systems research\\nYear: 2004\\n\\nAbstract: Two paradigms characterize much of the research in the Information Systems discipline: behavioral science and design science. The behavioral-science paradigm seeks to develop and verify theories that explain or predict human or organizational behavior. The design-science paradigm seeks to extend the boundaries of human and organizational capabilities by creating new and innovative artifacts. Both paradigms are foundational to the IS discipline, positioned as it is at the confluence of people, organizations, and technology. Our objective is to describe the performance of design-science research in Information Systems via a concise conceptual framework and clear guidelines for understanding, executing, and evaluating the research. In the design-science paradigm, knowledge and understanding of a problem domain and its solution are achieved in the building and application of the designed artifact. Three recent exemplars in the research literature are used to demonstrate the application of these guidelines. We conclude with an analysis of the challenges of performing high-quality design-science research in the context of the broader IS community.\",\n \"Title: A model for the design of distributed databases (abstract only)\\nYear: 1985\\n\\nAbstract: This research is addressed towards solving a problem which falls under the general class of File Allocation Problems (FAP). The main purpose here is to provide a tool for the designer of a distributed database system. With an increasing number of enterprises tending towards distributed systems, a major research question that has come up is how to allocate resources (databases and programs) in a distributed environment. This question has been addressed by formulating a nonlinear integer programming model. Though the same issue has been addressed several times in the past, there is a major difference between the model developed here and all the other models. None of the models in the past have tried to solve the FAP by taking into account the concurrency control mechanism being used. This is a major deficiency of these models because allocation of files is partly based on the communication flows in a network of computers. The communication flows in turn are based on the concurrency control mechanism. It is this weakness that the research here has attempted to overcome by designing a more realistic model.\",\n \"Title: Who does what: Collaboration patterns in the wikipedia and their impact on article quality\\nYear: 2011\\n\\nAbstract: The quality of Wikipedia articles is debatable. On the one hand, existing research indicates that not only are people willing to contribute articles but the quality of these articles is close to that found in conventional encyclopedias. On the other hand, the public has never stopped criticizing the quality of Wikipedia articles, and critics never have trouble finding low-quality Wikipedia articles. Why do Wikipedia articles vary widely in quality? We investigate the relationship between collaboration and Wikipedia article quality. We show that the quality of Wikipedia articles is not only dependent on the different types of contributors but also on how they collaborate. Based on an empirical study, we classify contributors based on their roles in editing individual Wikipedia articles. We identify various patterns of collaboration based on the provenance or, more specifically, who does what to Wikipedia articles. Our research helps identify collaboration patterns that are preferable or detrimental for article quality, thus providing insights for designing tools and mechanisms to improve the quality of Wikipedia articles.\",\n \"Title: The relational model is dead, SQL is dead, and I don't feel so good myself\\nYear: 2013\\n\\nAbstract: We report the opinions expressed by well-known database researchers on the future of the relational model and SQL during a panel at the International Workshop on Non-Conventional Data Access (NoCoDa 2012), held in Florence, Italy in October 2012 in conjunction with the 31st International Conference on Conceptual Modeling. The panelists include: Paolo Atzeni (Università Roma Tre, Italy), Umeshwar Dayal (HP Labs, USA), Christian S. Jensen (Aarhus University, Denmark), and Sudha Ram (University of Arizona, USA). Quotations from movies are used as a playful though effective way to convey the dramatic changes that database technology and research are currently undergoing.\",\n \"Title: A Semantic Foundation for Provenance Management.\\nYear: 2012\\n\\nAbstract: Provenance is a term used to describe the lineage, history, or origin of an object. While provenance originated from the art world, it is now becoming increasingly important in the context of digital objects on the World Wide Web. Large scale scientific collaborations and social media platforms on the web have enabled production and sharing of a variety of digital objects on the web. With the proliferation and sharing of such objects, which include documents, pictures, videos, and more, questions such as “where did this object come from?”, “who else is using this object?” and “for what purpose was it generated?” are becoming increasingly common. To ensure that digital objects from different sources can be trusted and used appropriately, it is imperative that the provenance of the digital objects be tracked, recorded, and made available to its users. In this work, we attempt to provide a foundation for understanding provenance, clearly define the semantics of provenance, distinguish provenance from “uses or application” of provenance, suggest a mechanism for managing provenance, and provide important directions for research in provenance management.\",\n \"Title: Elitist and Ensemble Strategies for Cascade Generalization\\nYear: 2006\\n\\nAbstract: Several methods have been proposed for cascading other classification algorithms with decision tree learners to alleviate the representational bias of decision trees and, potentially, to improve classification accuracy. Such cascade generalization of decision trees increases the flexibility of the decision boundaries between classes and promotes better fitting of the training data. However more flexible models may not necessarily lead to more predictive power. Because of polential overfitting problems, the true classification accuracy on test data may not increase. Recently, a generic method for cascade generalization has been proposed. The method uses a parameter-the maximum cascading depth-to constrain the degree that other classification algorithms are cascaded with decision tree learners. A method for efficiently learning a collection (i.e., a forest) of generalized decision trees, each with other classification algorithms cascaded to a particular depth, also has been developed In this article, we propose several new strategies, including elitist and ensemble (weighted or unweighted), for using the various decision trees in such a collection in the prediction phase. Our empirical evaluation using 32 data sets in the UCI machine learning repository shows that, on average, the elitist strategy outperforms the weighted full ensemble strategy, which, in turn, outperforms the unweighted full ensemble strategy. However no strategy is universally superior across all applications. Since the same training process can be used to evaluate the various strategies, we recommend that several promising strategies be evaluated and compared before selecting the one to use for a given application.\",\n \"Title: Collaborative conceptual schema design: a process model and prototype system\\nYear: 1998\\n\\nAbstract: Recent years have seen an increased interest in providing support for collaborative activities among groups of users participating in various information systems design tasks such as, requirements determination and process modeling. However, little attention has been paid to the collaborative conceptual database design process. In this article, we develop a model of the collaborative conceptual schema development process and describe the design and implementation of a graphical multiuser conceptual schema design tool that is based on the model. The system we describe allows a group of users to work collaboratively on the creation of database schemas in synchronous (same-time) mode (either in a face-to-face or distributed setting). Extensive modeling support is provided to assist users in creating semantically correct conceptual schemas. The system also provides users with several graphical facilities such as, a large drawing workspace with the ability to scroll or “jump” to any portion of this workspace, zooming capabilities, and the ability to move object(s) to any portion of the workspace. The unique component of the system, however, is its built-in support for collaborative schema design. The system supports a relaxed WYSIWIS environment, i.e., each user can control the graphical layout of the same set of schema objects. The system ensures that changes/additions made by any user are consistent. Any conflicts that may compromise to the integrity of the shared schema are flagged and resolved by the system. The results from a preliminary experiment suggest that the use of our system in a collaborative mode improved information sharing among users, minimized conflicts, and led to a more comprehensive schema definition.\",\n \"Title: Transaction management mechanisms for active and real-time databases: a comprehensive protocol and a performance study\\nYear: 1998\\n\\nAbstract: Active and real-time databases (ARTDB) have a variety of applications in electronic brokerages in financial markets, stock trading, network management and manufacturing process control. Transaction processing (TP) in ARTDB is extremely complicated since transactions may trigger other real-time transactions to an arbitrary depth with various types of dependencies (coupling modes). Therefore, transaction processing must be cognizant of not only the time deadlines but also the types of semantic dependencies with other transactions. The conflict resolution between two transactions cannot be considered in isolation since affecting one transaction may affect every other semantically dependent transaction. Similarly, transaction scheduling needs to be compatible with the concurrency control to avoid unnecessary restarts. In this paper we argue that transaction pre-analysis using the pre-declaration paradigm is an efficient mechanism to integrate the various issues of transaction processing such as concurrency control, scheduling, and semantic dependencies. The pre-analysis is possible since in many applications transactions repeat from a set of transaction classes, and the conflicts can be easily determined at a logical level by partitioning relations into mutually exclusive subset (e.g., by stock-id in financial applications). We develop a pre-analysis based transaction processing mechanism called OCCWB. OCCWB is an extended optimistic concurrency control protocol with blocking that combines the benefits of both optimistic and lock based protocols. Such an approach also has an implicit overload management mechanism required in many applications. OCCWB consists of four phases, namely, transaction pre-analysis, serialization ordering, priority adjustment and priority wait. Our protocol is validated using simulation and is shown to outperform existing protocols under various workload and parameter settings.\",\n \"Title: Integrity constraint integration in heterogeneous databases: an enhanced methodology for schema integration\\nYear: 1997\\n\\nAbstract: In today's technologically diverse corporate environment, it is common to find several different databases being used to accomplish the organization's operational data management functions. Providing interoperability among these databases is important to the successful operation of the organization. One approach to providing interoperability among heterogeneous database systems, is to define one or more schemas which represent a coherent view of the underlying databases. In the past, most approaches have used schematic knowledge about the underlying databases to generate integrated representations of the databases. In this paper we present a seven step methodology for utilizing integrity constraint knowledge from heterogeneous databases. Specifically, we describe how we can generate a set of integrity constraints applicable at the integrated level from constraints specified on local databases. We introduce the concept of constraint-based relationships between objects in heterogeneous databases and describe the role that these relationships play in integrity constraint integration. Finally, we describe how the integrated set of constraints generated using our methodology can be used to facilitate semantic query processing in a heterogeneous database environment.\",\n \"Title: An Agent-Based Approach For Sourcing Business Rules In Supply Chain Management\\nYear: 2005\\n\\nAbstract: In recent years, business rule management has become an important component of enterprise information systems. Business rules represent guidelines about how an enterprise should conduct its business and provide better service for customers. Business rules are being widely deployed in supply chains to support real-time decision making. The research reported in this paper is aimed at designing a dynamically adaptable data-sourcing service for deploying business rules effectively in supply chain management. Such a data-sourcing service is important since execution of business rules requires data to be retrieved from various data sources spread across the enterprise, including the enterprise data warehouse. We propose a semantics-based approach to implement the data-sourcing service for business rules. Our approach captures semantics of business rules and provides an agent-enabled mechanism that dynamically maps business rules to the enterprise data model. A prototype system is implemented to illustrate our sourcing service and demonstrate the feasibility of our approach.\",\n \"Title: Supporting User-Defined Granularities in a Spatiotemporal Conceptual Model\\nYear: 2002\\n\\nAbstract: Granularities are integral to spatial and temporal data. A large number of applications require storage of facts along with their temporal and spatial context, which needs to be expressed in terms of appropriate granularities. For many real-world applications, a single granularity in the database is insufficient. In order to support any type of spatial or temporal reasoning, the semantics related to granularities needs to be embedded in the database. Specifying granularities related to facts is an important part of conceptual database design because under-specifying the granularity can restrict an application, affect the relative ordering of events and impact the topological relationships. Closely related to granularities is indeterminacy, i.e., an occurrence time or location associated with a fact that is not known exactly. In this paper, we present an ontology for spatial granularities that is a natural analog of temporal granularities. We propose an upward-compatible, annotation-based spatiotemporal conceptual model that can comprehensively capture the semantics related to spatial and temporal granularities, and indeterminacy without requiring new spatiotemporal constructs. We specify the formal semantics of this spatiotemporal conceptual model via translation to a conventional conceptual model. To underscore the practical focus of our approach, we describe an on-going case study. We apply our approach to a hydrogeologic application at the United States Geologic Survey and demonstrate that our proposed granularity-based spatiotemporal conceptual model is straightforward to use and is comprehensive.\",\n \"Title: Clustering Schema Elements for Semantic Integration of Heterogeneous Data Sources\\nYear: 2004\\n\\nAbstract: Interschema relationship identification (IRI), that is, determining the relationships among schema elements in heterogeneous data sources, is an important step in integrating the data sources. This article proposes a cluster analysis based approach to semi-automating the IRI process, which is typically very time-consuming and requires extensive human interaction. The authors apply multiple clustering techniques, including K-means, hierarchical clustering, and self-organizing map (SOM) neural network, to identify similar schema elements from heterogeneous data sources, based on a combination of features such as naming similarity, document similarity, schema specification, data patterns, and usage patterns. An SOM prototype the authors have developed provides users with a visualization tool for display of clustering results as well as for incremental evaluation of candidate similar elements.\",\n \"Title: Predicting Asthma-Related Emergency Department Visits Using Big Data.\\nYear: 2015\\n\\nAbstract: Asthma is one of the most prevalent and costly chronic conditions in the United States which cannot be cured. However accurate and timely surveillance data could allow for timely and targeted interventions at the community or individual level. Current national asthma disease surveillance systems can have data availability lags of up to two weeks. Rapid progress has been made in gathering non-traditional, digital information to perform disease surveillance. We introduce a novel method of using multiple data sources for predicting the number of asthma related emergency department (ED) visits in a specific area. Twitter data, Google search interests and environmental sensor data were collected for this purpose. Our preliminary findings show that our model can predict the number of asthma ED visits based on near-real-time environmental and social media data with approximately 70% precision. The results can be helpful for public health surveillance, emergency department preparedness, and, targeted patient interventions.\",\n \"Title: Empirical analysis of implicit brand networks on social media\\nYear: 2014\\n\\nAbstract: This paper investigates characteristics of implicit brand networks extracted from a large dataset of user historical activities on a social media platform. To our knowledge, this is one of the first studies to comprehensively examine brands by incorporating user-generated social content and information about user interactions. This paper makes several important contributions. We build and normalize a weighted, undirected network representing interactions among users and brands. We then explore the structure of this network using modified network measures to understand its characteristics and implications. As a part of this exploration, we address three important research questions: (1) What is the structure of a brand-brand network? (2) Does an influential brand have a large number of fans? (3) Does an influential brand receive more positive or more negative comments from social users? Experiments conducted with Facebook data show that the influence of a brand has (a) high positive correlation with the size of a brand, meaning that an influential brand can attract more fans, and, (b) low negative correlation with the sentiment of comments made by users on that brand, which means that negative comments have a more powerful ability to generate awareness of a brand than positive comments. To process the large-scale datasets and networks, we implement MapReduce-based algorithms.\",\n \"Title: Capturing Telic/Atelic Temporal Data Semantics: Generalizing Conventional Conceptual Models\\nYear: 2014\\n\\nAbstract: Time provides context for all our experiences, cognition, and coordinated collective action. Prior research in linguistics, artificial intelligence, and temporal databases suggests the need to differentiate between temporal facts with goal-related semantics (i.e., telic) from those are intrinsically devoid of culmination (i.e., atelic). To differentiate between telic and atelic data semantics in conceptual database design, we propose an annotation-based temporal conceptual model that generalizes the semantics of a conventional conceptual model. Our temporal conceptual design approach involves: 1) capturing \\\"what\\\" semantics using a conventional conceptual model; 2) employing annotations to differentiate between telic and atelic data semantics that help capture \\\"when\\\" semantics; 3) specifying temporal constraints, specifically nonsequenced semantics, in the temporal data dictionary as metadata. Our proposed approach provides a mechanism to represent telic/atelic temporal semantics using temporal annotations. We also show how these semantics can be formally defined using constructs of the conventional conceptual model and axioms in first-order logic. Via what we refer to as the \\\"semantics of composition,\\\" i.e., semantics implied by the interaction of annotations, we illustrate the logical consequences of representing telic/atelic data semantics during temporal conceptual design.\",\n \"Title: Screening financial innovations: an expert system approach\\nYear: 1990\\n\\nAbstract: An expert system, called Innovator, that helps a financial-service organization (FSO) evaluate new products it does not currently offer is described. Innovator was implemented using a rule-based expert system shell called Expert System Environment. The authors examine why FSOs need expert systems for screening financial innovations. The knowledge-representation and implementation details, and the system validation process are described. Innovator's benefits and continuing research are discussed.<>\",\n \"Title: RT @News: An Analysis of News Agency Ego Networks in a Microblogging Environment.\\nYear: 2015\\n\\nAbstract: News agencies regularly use Twitter to publicize and increase readership of their articles. Although substantial research on the spread of news on Twitter exists, there hasn't been much focus on the study of the spread of news articles. In this study, we present an innovative methodology involving weighted ego networks to understand how news agencies propagate news articles using their Twitter handle. We propose a set of measures to compare the propagation process of different news agencies by studying important aspects such as volume, extent of spread, conversion rate, multiplier effect, lifespan, hourly response, and audience participation. Using a dataset of tweets collected over a period of 6 months, we apply our methodology and suggest a framework to help news agencies gauge their performance on social media and also provide critical insights into the phenomenon of news article propagation on Twitter.\",\n \"Title: Predicting Location-Based Sequential Purchasing Events by Using Spatial, Temporal, and Social Patterns\\nYear: 2015\\n\\nAbstract: Location-based sequential event prediction is an interesting problem with many real-world applications. For example, knowing when and where people will use certain kinds of services could enable the development of robust anticipatory systems. A key to this problem is in understanding the nature of the process from which sequential data arises. Usually, human behavior exhibits distinct spatial, temporal, and social patterns. The authors examine three kinds of patterns extracted from sequential purchasing events and propose a novel model that captures contextual dependencies in spatial sequence, customers' temporal preferences, and social influence via an implicit network. Their model outperforms existing models based on evaluations using a real-world dataset of smartcard transaction records from a large educational institution with 13,753 students during a 10-month time period.\",\n \"Title: Extracting Signals from Social Media for Chronic Disease Surveillance.\\nYear: 2016\\n\\nAbstract: Asthma is a chronic disease that affects people of all ages, and is a serious health and economic concern worldwide. However, accurate and timely surveillance and predicting hospital visits could allow for targeted interventions and reduce the societal burden of asthma. Current national asthma disease surveillance systems can have data availability lags of up to months and years. Rapid progress has been made in gathering social media data to perform disease surveillance and prediction. We introduce novel methods for extracting signals from social media data to assist in accurate and timely asthma surveillance. Our empirical analyses show that our methods are very effective for surveillance of asthma prevalence at both state and municipal levels. They are also useful for predicting the number of hospital visits based on near-real-time social media data for specific geographic areas. Our results can be used for public health surveillance, ED preparedness, and targeted patient interventions.\",\n \"Title: Feature Importance and Predictive Modeling for Multi-source Healthcare Data with Missing Values.\\nYear: 2016\\n\\nAbstract: With rapid development of sensor technologies and the internet of things, research in the area of connected health is increasing in importance and complexity with wide-reaching impacts for public health. As data sources such as mobile (wearable) sensors get cheaper, smaller, and smarter, important research questions can be answered by combining information from multiple data sources. However, integration of multiple heterogeneous data streams often results in a dataset with several empty cells or missing values. The challenge is to use such sparsely populated integrated datasets without compromising model performance. Naïve approaches for dataset modification such as discarding observations or ad-hoc replacement of missing values often lead to misleading results. In this paper, we discuss and evaluate current best-practices for modeling such data with missing values and then propose an ensemble-learning based sparse-data modeling framework. We develop a predictive model using this framework and compare it with existing models using a study in a healthcare setting. Instead of generating a single score on variable/feature importance, our framework enables the user to understand the importance of a variable based on the existing data values and their localized impact on the outcome.\",\n \"Title: SMARTBUS: A Web Application for Smart Urban Mobility and Transportation.\\nYear: 2016\\n\\nAbstract: Systematic evaluation is crucial to the management and development of smart urban transportation, as it allows transportation planners to better understand the impact of their decisions and design targeted interventions to improve efficiency. Implementation of smart and adaptable public transportation is an important challenge in developing cities and newly industrialized economies where growth characteristics contribute to and can be impacted by factors like overcrowding and travel delays. In this paper, we focus on bus transportation, and present the design and implementation of a 3-layer web-based system for performance evaluation and decision support. This is part of a \\\"Smart Cities\\\" initiative, which is an international collaboration between academia and government. The first layer estimates fundamental indicators such as bus travel time and passenger demands by integrating heterogeneous data sources. A novel bus-stop network is then designed in the second layer, which enables the derivation of passenger patterns in public transit using network analysis. The third layer provides decision support by analyzing causal relationships between indicators. The proposed web-based system called SMARTBUS is being developed and validated with the city of Fortaleza in Brazil. We believe the use of generally available urban transportation data makes our methodology adaptable and customizable for other cities.\",\n \"Title: Understanding the Competitive Landscape of News Providers on Social Media.\\nYear: 2016\\n\\nAbstract: Social media has emerged as a mechanism for online news propagation. This in turn has changed the competitive landscape of news providers, a landscape that was previously partitioned based on the traditional channels of news dispersion. The channels of news distribution refer to - television, newspaper, magazine, radio, news agency and online only. In this paper, we examine similarities and differences in news propagation patterns on social media based on the primary channel of a news provider. We collected news article propagation activity data from Twitter for 32 news providers over a three-week period and analyzed their propagation networks. Our analysis shows that the structural properties of the propagation networks are statistically different based on the type of primary channel. Our study has useful implications for understanding the competition between news providers in an online environment.\",\n \"Title: Smartbike: Policy Making And Decision Support For Bike Share Systems\\nYear: 2016\\n\\nAbstract: Bike share systems have been implemented in many cities to provide an alternative low-cost environmentally friendly and healthy public transportation. Citizens can pick up and drop off bikes among stations around the city. The system may be used for both work-related and leisure purposes including supporting last-mile transportation and tourism. In order to sustain and attract more users into the bike system, understanding demand and trip patterns is a key objective. Further, due to the asymmetric and dynamic nature of user demands, some stations tend to run out of bikes whereas other stations tend to be full ( impeding returns). Rebalancing stations to provide high quality services to fit pick up and drop off demand is a major challenge in bike share systems. In this paper, we present a three-layer SMARTBIKE system to assist city administrators in Fortaleza, Brazil with bike share system decision making. This is an international cooperative effort between academia and government to aid in building a Smart City. The first layer of the proposed tool includes k-means clustering technology to understand the true demand of the city bike share system. We designed a novel station network analysis in the second layer to provide insights on system usage patterns and to help with the rebalancing strategy. The third layer provides rebalancing support at the facility and operation level. Finally, we discuss a dynamic visualization tool to support decision making.\",\n \"Title: A Big Data Approach For Smart Transportation Management On Bus Network\\nYear: 2016\\n\\nAbstract: Urbanization in developing countries has resulted in increased demand for public transportation in the face of limited resources. This requires smart transportation management that allows urban planners to evaluate the impact of their policies and design targeted interventions. This paper proposes a three-layer management system to support smart urban mobility with an emphasis on bus transportation. In Layer-1, we apply novel Big Data techniques to compute bus travel time and passenger demands in an efficient and economical way. Layer-2 contains two analytic components: network analysis of passenger transit patterns and causal relationship analysis for bus delays. The third layer provides decision support in an interactive visualization environment. The proposed system is developed and validated in cooperation with the city of Fortaleza in Brazil. The use of generally available urban transportation data makes our methodology adaptable and customizable for other cities.\",\n \"Title: Large-Scale Network Analysis for Online Social Brand Advertising.\\nYear: 2016\\n\\nAbstract: This paper proposes an audience selection framework for online brand advertising based on user activities on social media platforms. It is one of the first studies to our knowledge that develops and analyzes implicit brand-brand networks for online brand advertising. This paper makes several contributions. We first extract and analyze implicit weighted brand-brand networks, representing interactions among users and brands, from a large dataset. We examine network properties and community structures and propose a framework combining text and network analyses to find target audiences. As a part of this framework, we develop a hierarchical community detection algorithm to identify a set of brands that are closely related to a specific brand. This latter brand is referred to as the \\\"focal brand.\\\" We also develop a global ranking algorithm to calculate brand influence and select influential brands from this set of closely related brands. This is then combined with sentiment analysis to identify target users from these selected brands. To process large-scale datasets and networks, we implement several MapReduce-based algorithms. Finally, we design a novel evaluation technique to test the effectiveness of our targeting framework. Experiments conducted with Facebook data show that our framework provides significant performance improvements in identifying target audiences for focal brands.\",\n \"Title: A Regularization Approach for Identifying Cumulative Lagged Effects in Smart Health Applications.\\nYear: 2017\\n\\nAbstract: Recent development of wearable sensor technologies have made it possible to capture concurrent data streams for ambient environment and instantaneous physiological stress response at a fine granularity. Characterizing the delay in physiological stress response time to each environment stimulus is as important as capturing the magnitude of the effect. In this paper, we discuss and evaluate a new regularization-based statistical method to determine the ideal lagged effect of five environmental factors-carbon dioxide, temperature, relative humidity, atmospheric pressure and noise levels on instantaneous stress response. Using this method, we infer that the first four environment variables have a cumulative lagged effect, of approximately 60 minutes, on stress response whereas noise level has an instantaneous effect on stress response. The proposed transformations to inputs result in models with better fit and predictive performance. This study not only informs the field of environment-wellbeing research about the cumulative lagged effects of the specified environmental factors, but also proposes a new method for determining optimal feature transformation in similar smart health studies.\",\n \"Title: Improving the Domain Independence of Data Provenance Ontologies: A Demonstration Using Conceptual Graphs and the W7 Model\\nYear: 2017\\n\\nAbstract: AbstractProvenance is becoming increasingly important as more and more people are using data that they themselves did not generate. In the last decade, significant efforts have been directed toward developing generic, shared data provenance ontologies that support the interoperability of provenance across systems. An issue that is impeding the use of such provenance ontologies is that a generic provenance ontology, no matter how complete it is, is insufficient for capturing the diverse, complex provenance requirements in different domains. In this paper, the authors propose a novel approach to adapting and extending the W7 model, a well-known generic ontology of data provenance. Relying on various knowledge expansion mechanisms provided by the Conceptual Graph formalism, the authors' approach enables us to develop domain ontologies of provenance in a disciplined yet flexible way.\",\n \"Title: Predicting interpurchase time in a retail environment using customer-product networks: An empirical study and evaluation.\\nYear: 2018\\n\\nAbstract: •We leverage similarities in customer purchases for product attrition prediction.•We extract an extensive feature set from customer-product graphs.•We boost predictive performance by 6% and product identification by 20%.•Our model illustrates the importance of transactional data for marketing.•We show the advantage of network-based analytics in offline retail.\",\n \"Title: Using big data and network analysis to understand Wikipedia article quality.\\nYear: 2018\\n\\nAbstract: The research reported in this paper focuses on the question of why Wikipedia articles are different in quality. Since these articles are developed in an open and social environment, our work investigates if the social capital of contributors plays a role in determining the quality of the articles. We focus on three major types of social capital with respect to teams of contributors working on Wikipedia articles: internal bonding, external bridging and functional diversity. Through a social network analysis of these articles based on a dataset extracted from its edit history, our research finds that all three types of social capital have a significant impact on their quality. In addition, we found that internal bonding interacts positively with external bridging resulting in a multiplier effect on article quality. The findings of our research have implications for developing automated techniques for quality assessment of Wikipedia and also provide insights into improving quality of these articles.\",\n \"Title: Uncovering the effects of digital movie format availability on physical movie sales.\\nYear: 2019\\n\\nAbstract: The impact of multi-channel technology-enabled digital goods on the sales of the physical counterpart faces uncertainty in the electronic commerce domain. We address the issue empirically by identifying the effect of the availability of digitally-delivered movies on physical DVD movie sales. Unique to our study is our interest in not only purchased digital goods but rented digital goods as well. We construct a robust panel dataset consisting of movie data collected from Amazon and Barnes and Noble on the same day for every movie observed. A key feature of our dataset is the multi-channel availability of digital purchase and digital rental movie formats at Amazon. Our results show that the availability of the digital purchase format does not have a significant effect on DVD sales. Surprisingly, the availability of the digital rental format is associated with a significant reduction in DVD sales. The results imply that a product substitution effect may be occurring between the digital rental and the physical DVD purchase of the same movie. We conduct robustness tests to show under which conditions the effect is greatest. Our results also provide practical implications to inform strategies regarding movie format release windows.\",\n \"Title: When entities are types: effectively modeling type-instantiation relationships\\nYear: 2010\\n\\nAbstract: Type-instantiation relationships (TIRs) appear in many application domains including RFID-based inventory tracking, securities markets, health care, incident-response management, travel, advertising, and academia. For example an emergency response (type) is instantiated in the actual incident, or an advertisement (type) serves impressions on a website. This kind of relationship has received little attention in literature notwithstanding its ubiquity. Conventional modeling does not properly capture its underlying semantics. This can lead to data redundancy, denormalized relations and loss of knowledge about constraints during implementation. Our work formally defines and discusses the semantics of the type-instantiation relationship. We also present an analysis of how TIRs affect other relationships in a conceptual database schema, and the relational implications of our approach.\",\n \"Title: Digital Libraries for the Next Millennium: Challenges and Research Directions\\nYear: 1999\\n\\nAbstract: The unprecedented growth of Internet technologies has made resources on the World Wide Web instantly accessible to various user communities through digital libraries. Since the early 1990s, there have been several digital library initiatives sponsored by government agencies and/or private organizations all over the world. A digital library is a networked system environment that provides diverse user communities with coherent, seamless and transparent access to large, organized, and digitized information resources. This article provides a comprehensive overview of major digital library projects that are currently being undertaken across the globe. We also identify and discuss major challenges and research issues to be addressed in the design and implementation of digital libraries for the next millennium. We believe that digital libraries are ripe with research opportunities, offer many challenges, and will continue to grow in the next several years.\",\n \"Title: Understanding Semantic Completeness in Rule Frameworks for Modeling Cardinality Constraints.\\nYear: 2018\\n\\nAbstract: Modeling organizational rules during conceptual design provides a more accurate picture of the underlying domain and helps enforce data integrity. In a database development context, there are many advantages to explicitly representing rules during conceptual design. Early modeling ensures they are visible to designers and users, thus improving requirements and validation. The rules can then be semi-automatically translated into logical design code. One limitation to widespread adoption of such modeling is variance in standards and semantics of rules. We consider cardinality constraints-a useful and integral part of conceptual database design. Many papers discussing classification frameworks for cardinality exist. Completeness of such schemes has always been in question since well-defined criteria do not exist to evaluate them. We suggest a \\\"reverse engineering\\\" approach, i.e., one of defining conceptual modeling constraint completeness based on mappings from the relational model. We develop a correspondence from relational algebra operator combinations to existing semantic constraint types. In doing so, we also come up with a new category of set-level cardinality constraints not previously examined in literature. We believe our work demonstrates a unique approach to establishing conceptual framework completeness and enables standardization of rule semantics which in turn allows for semantics-based (as opposed to procedural-based) representation. On the implementation side, it supports developing automated mechanisms for translating constraints to improve developer productivity.\",\n \"Title: Evaluating Distributed Computing Infrastructures: An Empirical Study Comparing Hadoop Deployments on Cloud and Local Systems\\nYear: 2021\\n\\nAbstract: The popularity of distributed computing platforms (e.g., Hadoop) is largely due to their ability to address scalability issues that arise from data storage and processing limitations of standard computing systems. However, the decision to dedicate organizational resources and capital for such systems needs a careful consideration of several factors including evaluation of cloud-based distributed c...\",\n \"Title: Finding A Needle In The Haystack: Recommending Online Communities On Social Media Platforms Using Network And Design Science\\nYear: 2021\\n\\nAbstract: We address the problem of recommending online communities on social media platforms using design science. Our method is grounded in network science and leverages the random surfer model of the web, small-world networks, strength of weak connections, and connectivity to analyze three types of large-scale networks. In doing so, we design features for structural hole assortativity and local clustering coefficient rank to capture both the diversity and evolution of user interests. We also extract general online community features such as size and overlap. Experiments conducted on a large dataset of 34,000 lists created and subscribed to by 1,600 active Twitter users over a six-month period showed that our network features outperform the general and content features in terms of recommending communities at the top position. In addition, a combination of general and network features generated the best results in the top position with a significant performance improvement over using only the content features. A combination of all three types of features gave the best results in the top-5 and top-10 positions while improving the quality of recommendations at every other position. Our work outperforms the latest work on community recommendations on social media platforms and has major implications for the design of online community recommenders.\",\n \"Title: Artifiicial Intelligence in Information Systems: State of the Art and Research Roadmap\\nYear: 2022\\n\\nAbstract: Many would argue that artificial intelligence (AI) is not only technology but also a paradigmatic shift in the relationship between humans and machines. Much literature assumes that AI-powered practices substantially differ from and profoundly change organizational structures, communication, affordances, and ecosystems. However, AI research remains fragmented and often lacks clarity. While the information systems (IS) discipline can play a pivotal role in AI's emergence and use, the discipline needs a clear direction that specifies how it can contribute and its key research themes and questions. This paper draws on a professional development workshop that we organized at the 2020 International Conference on Information Systems and the discussions that followed. We summarize and synthesize how AI has impacted organizational practices over five decades and provide views from various perspectives. We identify weaknesses in the current AI literature as measured against conceptual clarity, theoretical glue, cumulative tradition, parsimony, and applicability. We also identify direct actions that the IS research community can undertake to address these issues. Finally, we propose a next-step research agenda to guide AI research in the coming years.\",\n \"Title: Deep Learning of Spatiotemporal Patterns for Urban Mobility Prediction Using Big Data\\nYear: 2022\\n\\nAbstract: Timely and accurate prediction of human movement in urban areas offers instructive insights into transportation management, public safety, and location-based services, to name a few. Yet, modeling urban mobility is challenging and complex because of the spatiotemporal dynamics of movement behavior and the influence of exogenous factors such as weather, holidays, and local events. In this paper, we use bus transportation as a proxy to mine spatiotemporal travel patterns. We propose a deep-learning-based urban mobility prediction model that collectively forecasts passenger flows between pairs of city regions in an origin-destination (OD) matrix. We first process OD matrices in a convolutional neural network to capture spatial correlations. Intermediate results are reconstructed into three multivariate time series: hourly, daily, and weekly time series. Each time series is aggregated in a long short-term memory (LSTM) network with a novel attention mechanism to guide the aggregation. In addition, our model is context-aware by using contextual embeddings learned from exogenous factors. We dynamically merge results from LSTM components and context embeddings in a late fusion network to make a final prediction. The proposed model is implemented and evaluated using a large-scale transportation data set of more than 200 million bus trips with a suite of Big Data technologies developed for data processing. Through performance comparison, we show that our approach achieves sizable accuracy improvements in urban mobility prediction. Our work has major implications for efficient transportation system design and performance improvement. The proposed deep neural network structure is generally applicable for sequential graph data prediction.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":79,"string":"79"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13376,"string":"13,376"}}},{"rowIdx":13377,"cells":{"question_id":{"kind":"string","value":"Byron Cook"},"question":{"kind":"string","value":"Generate an abstract for the title \"Advances in proving program termination and liveness\" using the following items: 1. Halting problem\n2. Undecidability\n3. Termination\n4. Liveness properties\n5. Temporal properties"},"answer":{"kind":"string","value":"Because the halting problem is undecidable, many have considered the dream of automatically proving termination (and other liveness properties) to be impossible. While not refuting Turing's original result of undecidability, recent research now makes this dream a practical reality. I will describe this recent work and its application to industrial software and models of biological systems. I will also describe recent adaptations of these new technologies to the problem of proving temporal properties in logics such as CTL and LTL."},"correct_answer":{"kind":"string","value":"Because the halting problem is undecidable, many have considered the dream of automatically proving termination (and other liveness properties) to be impossible. While not refuting Turing's original result of undecidability, recent research now makes this dream a practical reality. I will describe this recent work and its application to industrial software and models of biological systems. I will also describe recent adaptations of these new technologies to the problem of proving temporal properties in logics such as CTL and LTL."},"documents":{"kind":"list like","value":["Title: SLAYER: memory safety for systems-level code\nYear: 2011\n\nAbstract: SLAyer is a program analysis tool designed to automatically prove memory safety of industrial systems code. In this paper we describe SLAyer's implementation, and its application to Windows device drivers. This paper accompanies the first release of SLAYER.","Title: Terminator: Beyond Safety\nYear: 2006\n\nAbstract: Previous symbolic software model checkers (i.e., program analysis tools based on predicate abstraction, pushdown model check- ing and iterative counterexample-guided abstraction refinement, etc.) are restricted to safety properties. Terminator is the first software model checker for termination. It is now being used to prove that device driver dispatch routines always return to their caller (or return counterexamples if they if they fail to terminate).","Title: Proving Conditional Termination\nYear: 2008\n\nAbstract: We describe a method for synthesizing reasonable underap- proximations to weakest preconditions for termination—a long-standing open problem. The paper provides experimental evidence to demonstrate the usefulness of the new procedure.","Title: Proving program termination\nYear: 2011\n\nAbstract: In contrast to popular belief, proving termination is not always impossible.","Title: Automatically Proving Program Termination\nYear: 2007\n\nAbstract: In this talk I will describe new tools that allow us to automatically prove termination and other liveness properties of software\n systems. In particular I will discuss the Terminator program termination prover and its application to the problem of showing\n that Windows device driver event-handling routines always eventually stop responding to events.","Title: Verification of Boolean programs with unbounded thread creation\nYear: 2007\n\nAbstract: Most symbolic software model checkers use abstraction techniques to reduce the verification of infinite-state programs to that of decidable classes. Boolean programs [T. Ball, S.K. Rajamani, Bebop: A symbolic model checker for Boolean programs, in: SPIN 00, in: Lecture Notes in Computer Science, vol. 1885, Springer, 2000, pp. 113-130] are the most popular representation for these abstractions. Unfortunately, today's symbolic software model checkers are limited to the analysis of sequential programs due to the fact that reachability in Boolean programs with unbounded thread creation is undecidable. We address this limitation with a novel algorithm for over-approximating reachability in Boolean programs with unbounded thread creation. Although the Boolean programs are not of finite state, the algorithm always reaches a fix-point. The fixed points are detected by projecting the state of the threads to the globally visible parts, which are finite.","Title: Proving Termination by Divergence.\nYear: 2007\n\nAbstract: A key challenge for software engineering is to learn how to reconcile the formal world of the machine and its software with the non-formal real world. In this paper, we discuss elements of Problem Oriented Software Engineering (POSE), an approach that ...","Title: Tractable reasoning in a fragment of separation logic\nYear: 2011\n\nAbstract: In 2004, Berdine, Calcagno and O'Hearn introduced a fragment of separation logic that allows for reasoning about programs with pointers and linked lists. They showed that entailment in this fragment is in coNP, but the precise complexity of this problem has been open since. In this paper, we show that the problem can actually be solved in polynomial time. To this end, we represent separation logic formulae as graphs and show that every satisfiable formula is equivalent to one whose graph is in a particular normal form. Entailment between two such formulae then reduces to a graph homomorphism problem. We also discuss natural syntactic extensions that render entailment intractable.","Title: Advances in Program Termination and Liveness\nYear: 2009\n\nAbstract: Recent research advances now allow us to automatically prove termination and other liveness properties of many industrial programs. In cases where the desired property does not hold for all inputs, tools can be used to synthesize a precondition on the inputs under which the property does hold. In this tutorial I will describe these recent advances and discuss our efforts to apply termination analysis to industrial software.","Title: Proving termination of nonlinear command sequences.\nYear: 2013\n\nAbstract: We describe a simple and efficient algorithm for proving the termination of a class of loops with nonlinear assignments to variables. The method is based on divergence testing for each variable in the cone-of-influence of the loop’s condition. The analysis allows us to automatically prove the termination of loops that cannot be handled using previous techniques. We also describe a method for integrating our nonlinear termination proving technique into a larger termination proving framework that depends on linear reasoning.","Title: Automatic termination proofs for programs with shape-shifting heaps\nYear: 2006\n\nAbstract: We describe a new program termination analysis designed to handle imperative programs whose termination depends on the mutation of the program's heap. We first describe how an abstract interpretation can be used to construct a finite number of relations which, if each is well-founded, implies termination. We then give an abstract interpretation based on separation logic formulæwhich tracks the depths of pieces of heaps. Finally, we combine these two techniques to produce an automatic termination prover. We show that the analysis is able to prove the termination of loops extracted from Windows device drivers that could not be proved terminating before by other means; we also discuss a previously unknown bug found with the analysis.","Title: A Framework for Microprocessor Correctness Statements\nYear: 2001\n\nAbstract: Most verifications of out-of-order microprocessors compare state-machine-based implementations and specifications, where the specification is based on the instruction-set architecture. The different efforts use a variety of correctness statements, implementations, and verification approaches. We present a framework for classifying correctness statements about safety that is independent of implementation representation and verification approach. We characterize the relationships between the different statements and illustrate how existing and classical approaches fit within this framework.","Title: Combining Stream-Based and State-Based Verification Techniques\nYear: 2000\n\nAbstract: Algebraic verification techniques manipulate the structure of a circuit while preserving its behavior. Algorithmic verification techniques verify properties about the behavior of a circuit. These two techniques have complementary strengths: algebraic techniques are largely independent of the size of the state space, and algorithmic techniques are highly automated. It is desirable to exploit both in the same verification. However, algebraic techniques often use stream-based models of circuits, while algorithmic techniques use state-based models. We prove the consistency of stream- and state-based interpretations of circuit models, and show how stream-based verification results can be used hand-in-hand with state-based verification results. Our approach allows us to combine stream-based algebraic rewriting and state-based reasoning, using SMV and SVC, to verify a pipelined microarchitecture with speculative execution.","Title: Shape analysis for composite data structures\nYear: 2007\n\nAbstract: We propose a shape analysis that adapts to some of the complex composite data structures found in industrial systems-level programs. Examples of such data structures include \"cyclic doubly-linked lists of acyclic singly-linked lists\", \"singly-linked lists of cyclic doubly-linked lists with back-pointers to head nodes\", etc. The analysis introduces the use of generic higher-order inductive predicates describing spatial relationships together with a method of synthesizing new parameterized spatial predicates which can be used in combination with the higher-order predicates. In order to evaluate the proposed approach for realistic programs we have performed experiments on examples drawn from device drivers: the analysis proved safety of the data structure manipulation of several routines belonging to an IEEE 1394 (firewire) driver, and also found several previously unknown memory safety bugs.","Title: Local reasoning for storable locks and threads\nYear: 2007\n\nAbstract: We present a resource oriented program logic that is able to reason about concurrent heap-manipulating programs with unbounded numbers of dynamically-allocated locks and threads. The logic is inspired by concurrent separation logic, but handles these more realistic concurrency primitives. We demonstrate that the proposed logic allows local reasoning about programs for which there exists a notion of dynamic ownership of heap parts by locks and threads.","Title: Refining Approximations in Software Predicate Abstraction\nYear: 2004\n\nAbstract: Predicate abstraction is an automatic technique that can be used to find abstract models of large or infinite-state systems. In tools like SLAM, where predicate abstraction is applied to software model checking, a number of heuristic approximations must be used to improve the performance of computing an abstraction from a set of predicates. For this reason, SLAM can sometimes reach a state in which it is not able to further refine the abstraction. In this paper we report on an application of Das & Dill's algorithm for predicate abstraction refinement. SLAM now uses this strategy lazily to recover precision in cases where the abstractions generated are too coarse. We describe how we have extended Das & Dill's original algorithm for use in software model checking. Our extension supports procedures, threads, and potential pointer aliasing. We also present results from experiments with SLAM on device driver sources from the Windows operating system.","Title: BMA: visual tool for modeling and analyzing biological networks\nYear: 2012\n\nAbstract: BioModel Analyzer (bma) is a tool for modeling and analyzing biological networks. Designed with a lightweight graphical user interface, the tool facilitates usage for biologists with no previous knowledge in programming or formal methods. The current implementation analyzes systems to establish stabilization. The results of the analysis--whether they be proofs or counterexamples--are represented visually. This paper describes the approach to modeling used in bma and also notes soon-to-be-released extensions to the tool.","Title: On embedding a microarchitectural design language within Haskell\nYear: 1999\n\nAbstract: Based on our experience with modelling and verifying microarchitectural designs within Haskell, this paper examines our use of Haskell as host for an embedded language. In particular, we highlight our use of Haskell's lazy lists, type classes, lazy state monad, and unsafe Perform I0, and point to several areas where Haskell could be improved in the future. We end with an example of a benefit gained by bringing the functional perspective to microarchitectural modelling.","Title: Predicate abstraction via symbolic decision procedures\nYear: 2005\n\nAbstract: We present a new approach for performing predicate abstraction based on\nsymbolic decision procedures. Intuitively, a symbolic decision procedure for a\ntheory takes a set of predicates in the theory and symbolically executes a\ndecision procedure on all the subsets over the set of predicates. The result of\nthe symbolic decision procedure is a shared expression (represented by a\ndirected acyclic graph) that implicitly represents the answer to a predicate\nabstraction query.\n We present symbolic decision procedures for the logic of Equality and\nUninterpreted Functions (EUF) and Difference logic (DIFF) and show that these\nprocedures run in pseudo-polynomial (rather than exponential) time. We then\nprovide a method to construct symbolic decision procedures for simple mixed\ntheories (including the two theories mentioned above) using an extension of the\nNelson-Oppen combination method. We present preliminary evaluation of our\nProcedure on predicate abstraction benchmarks from device driver verification\nin SLAM.","Title: Using stålmarck’s algorithm to prove inequalities\nYear: 2005\n\nAbstract: Stålmarck’s 1-saturation algorithm is an incomplete but fast method for computing partial equivalence relations over propositional formulae. Aside from anecdotal evidence, until now little has been known about what it can prove. In this paper we characterize a set of formulae with bitvector-inequalities for which 1-saturation is sufficient to prove unsatisfiability. This result has application to fast predicate abstraction for software with fixed-width bit-vectors.","Title: Finding heap-bounds for hardware synthesis\nYear: 2009\n\nAbstract: Abstract—Dynamically allocated and manipulated data struc- tures cannot be translated into hardware unless there is an upper bound on the amount,of memory,the program,uses during all executions. This bound,can depend on the generic parameters to the program, i.e., program inputs that are instantiated at synthesis time. We propose a constraint based method,for the discovery of memory usage bounds, which leads to the first- known,C-to-gates hardware synthesis supporting programs with non-trivial use of dynamically allocated memory, e.g., linked lists maintained withmalloc,andfree. We illustrate the practicality of our tool on a range of examples. I. I NTRODUCTION C-to-gates synthesis promises to bring the power,of hard- ware based acceleration to mainstream,programmers,and to radically increase the productivity of digital designers [ 17]. However, today’s C-to-gates synthesis tools do not support one of the most powerful and widely used features of high-level programming,in C—dynamically,allocated data structures. Thus, with today’s tools we usually cannot synthesize gates from off-the-shelf C-based software. The support for dynamic memory,abstraction remains,an on-going research problem","Title: Better termination proving through cooperation\nYear: 2013\n\nAbstract: One of the difficulties of proving program termination is managing the subtle interplay between the finding of a termination argument and the finding of the argument's supporting invariant. In this paper we propose a new mechanism that facilitates better cooperation between these two types of reasoning. In an experimental evaluation we find that our new method leads to dramatic performance improvements.","Title: Taming the Unbounded for Hardware Synthesis\nYear: 2009\n\nAbstract: The difficulty with compiling software to hardware is one of finding a priori bounds on the potentially unbounded resources used by programs: memory and time. New approaches now allow us to synthesize bounds on these resources, leading to new high-level hardware synthesis tools.","Title: Automatically Proving Concurrent Programs Correct\nYear: 2007\n\nAbstract: This talk will describe new advances that allow us to automatically prove both liveness properties and heap-shape properties of concurrent programs. The talk will focus on recent thread-modular extensions to the program termination prover TERMINATOR and shape analysis tool SLAyer and their application to Windows device drivers.","Title: Arithmetic Strengthening for Shape Analysis\nYear: 2007\n\nAbstract: Shape analyses are often imprecise in their numerical reason- ing, whereas numerical static analyses are often largely unaware of the shape of a program's heap. In this paper we propose a lazy method of combining a shape analysis based on separation logic with an arbitrary arithmetic analysis. When potentially spurious counterexamples are re- ported by our shape analysis, the method constructs a purely arithmetic program whose traces over-approximate the set of counterexample traces. It then uses this arithmetic program together with the arithmetic analy- sis to construct a refinement for the shape analysis. Our method is aimed at proving properties that require comprehensive reasoning about heaps together with more targeted arithmetic reasoning. Given a sucient pre- condition, our technique can automatically prove memory safety of pro- grams whose error-free operation depends on a combination of shape, size, and integer invariants. We have implemented our algorithm and tested it on a number of common list routines using a variety of arith- metic analysis tools for refinement.","Title: Proving Stabilization of Biological Systems\nYear: 2011\n\nAbstract: We describe an ecient procedure for proving stabilization of biological systems modeled as qualitative networks. For scalability, our procedure uses modular proof techniques, where state-space exploration is applied only locally to small pieces of the system rather than the en- tire system as a whole. Our procedure exploits the observation that, in practice, the form of modular proofs required can be restricted to a very limited set. Using our new procedure, we have solved a number of chal- lenging published examples, including a 3-D model of the mammalian epidermis, a model of metabolic networks operating in type-2 diabetes, and a model of fate determination of vulval precursor cells in the C. ele- gans worm. Our results show many orders of magnitude speedup in cases where previous stabilization proving techniques were known to succeed, and new results in cases where tools had previously failed.","Title: Ramsey vs. lexicographic termination proving\nYear: 2013\n\nAbstract: Termination proving has traditionally been based on the search for (possibly lexicographic) ranking functions. In recent years, however, the discovery of termination proof techniques based on Ramsey's theorem have led to new automation strategies, e.g. size-change, or iterative reductions from termination to safety. In this paper we revisit the decision to use Ramsey-based termination arguments in the iterative approach. We describe a new iterative termination proving procedure that instead searches for lexicographic termination arguments. Using experimental evidence we show that this new method leads to dramatic speedups.","Title: Reasoning about nondeterminism in programs\nYear: 2013\n\nAbstract: Branching-time temporal logics (e.g. CTL, CTL*, modal mu-calculus) allow us to ask sophisticated questions about the nondeterminism that appears in systems. Applications of this type of reasoning include planning, games, security analysis, disproving, precondition synthesis, environment synthesis, etc. Unfortunately, existing automatic branching-time verification tools have limitations that have traditionally restricted their applicability (e.g. push-down systems only, universal path quantifiers only, etc). In this paper we introduce an automation strategy that lifts many of these previous restrictions. Our method works reliably for properties with non-trivial mixtures of universal and existential modal operators. Furthermore, our approach is designed to support (possibly infinite-state) programs. The basis of our approach is the observation that existential reasoning can be reduced to universal reasoning if the system's state-space is appropriately restricted. This restriction on the state-space must meet a constraint derived from recent work on proving non-termination. The observation leads to a new route for implementation based on existing tools. To demonstrate the practical viability of our approach, we report on the results applying our preliminary implementation to a set of benchmarks drawn from the Windows operating system, the PostgreSQL database server, SoftUpdates patching system, as well as other hand-crafted examples.","Title: Precision and the Conjunction Rule in Concurrent Separation Logic\nYear: 2011\n\nAbstract: Concurrent separation logic is a Hoare logic for modular reasoning about concurrent heap-manipulating programs synchronising via locks. It achieves modular reasoning by partitioning the program state into thread-local and lock-protected parts, and assigning resource invariants to the latter. Surprisingly, the logic is unsound unless resource invariants are precise, i.e., unambiguously carve out an area of the heap. The counterexample showing the unsoundness involves the conjunction rule. However, to date it has been an open question whether concurrent separation logic without the conjunction rule is sound when the restriction on resource invariants is dropped: all the published proofs have the precision restriction baked in. In this paper we present a single proof that shows the soundness of the logic with imprecise resource invariants, but without the conjunction rule, as well as its classical version, where resource invariants are required to be precise and the conjunction rule is included. Our proof yields a precise and direct formulation of O@?Hearn@?s Separation Property and provides a semantic analysis of the logic that is much more elementary than previous proofs.","Title: SoftMC 2003: Workshop on Software Model Checking\nYear: 2003\n\nAbstract: This volume contains the Proceedings of the 2nd Workshop on Software Model Checking, which was held on 14 July 2003 in Boulder, Colorado. The Workshop was a satellite event of the Conference on Computer Aided Verification (CAV) 2003.","Title: Repair of boolean programs with an application to c\nYear: 2006\n\nAbstract: We show how to find and fix faults in Boolean programs by extending the program to a game. In the game, the protagonist can select an alternative implementation for an incorrect statement. If the protagonist can do so successfully using a memoryless strategy that does not depend on the stack contents, we have found a correction for the Boolean program. We present a symbolic algorithm that localizes possibly faulty statements and provides corrections. If the Boolean program is an abstraction of a C program, the repair for the Boolean program suggests a repair for the original C program. This yields a correct but incomplete approach to repairing C programs. We have applied this approach to Boolean programs that are produced as abstractions by SLAM and have thus successfully patched several faulty Windows device drivers.","Title: Over-Approximating Boolean Programs with Unbounded Thread Creation\nYear: 2006\n\nAbstract: This paper describes a symbolic algorithm for overapproximating reachability in Boolean programs with unbounded thread creation. The fix-point is detected by projecting the state of the threads to the globally visible parts, which are finite. Our algorithm models recursion by over-approximating the call stack that contains the return locations of recursive function calls, as reachability is undecidable in this case. The algorithm may obtain spurious counterexamples, which are removed iteratively by means of an abstraction refinement loop. Experiments show that the symbolic algorithm for unbounded thread creation scales to large abstract models.","Title: Summarization for termination: no return!\nYear: 2009\n\nAbstract: We propose a program analysis method for proving termination of recursive programs. The analysis is based on a reduction of termination to two separate problems: reachability of recursive programs, and termination of non-recursive programs. Our reduction works through a program transformation that modifies the call sites and removes return edges. In the new, non-recursive program, a procedure call may non-deterministically enter the procedure body (which means that it will never return) or apply a summary statement.","Title: Software engineering and formal methods\nYear: 2008\n\nAbstract: The answer to software reliability concerns may lie in formal methods.","Title: Formal Verification of Explicitly Parallel Microprocessors\nYear: 1999\n\nAbstract: The trend in microprocessor design is to extend instruction-set architectures with features--such as parallelism annotations, predication, speculative memory access, or multimedia instructions--that allow the compiler or programmer to express more instruction-level parallelism than the microarchitecture is willing to derive. In this paper we show how these instruction-set extensions can be put to use when formally verifying the correctness of a microarchitectural model. Inspired by Intel's IA-64, we develop an explicitly parallel instruction-set architecture and a clustered microarchitectural model. We then describe how to formally verify that the model implements the instruction set. The contribution of this paper is a specification and verification method that facilitates the decomposition of microarchitectural correctness proofs using instruction-set extensions.","Title: Interprocedural shape analysis with separated heap abstractions\nYear: 2006\n\nAbstract: We describe an interprocedural shape analysis that makes use of spatial locality (i.e. the fact that most procedures modify only a small subset of the heap) in its representation of abstract states. Instead of tracking reachability information directly and aliasing information indirectly, our representation tracks reachability indirectly and aliasing directly. Computing the effect of procedure calls and returns on an abstract state is easy because the representation exhibits spatial locality mirroring the locality that is present in the concrete semantics. The benefits of this approach include improved speed, support for programs that deallocate memory, the handling of bounded numbers of heap cutpoints, and support for cyclic and shared data structures.","Title: Cogent: accurate theorem proving for program verification\nYear: 2005\n\nAbstract: Many symbolic software verification engines such as Slam and ESC/Java rely on automatic theorem provers. The existing theorem provers, such as Simplify, lack precise support for important programming language constructs such as pointers, structures and unions. This paper describes a theorem prover, Cogent, that accurately supports all ANSI-C expressions. The prover's implementation is based on a machine-level interpretation of expressions into propositional logic, and supports finite machine-level variables, bit operations, structures, unions, references, pointers and pointer arithmetic. When used by Slam during the model checking of over 300 benchmarks, Cogent's improved accuracy reduced the number of Slam timeouts by half, increased the number of true errors found, and decreased the number of false errors.","Title: Scalable Shape Analysis for Systems Code\nYear: 2008\n\nAbstract: Pointer safety faults in device drivers are one of the leading causes of crashes in operating systems code. In principle, shape analysis tools can be used to prove the absence of this type of error. In practice, however, shape analysis is not used due to the unacceptable mixture of scalability and precision provided by existing tools. In this paper we report on a new join operation ${\\sqcup\\dagger}$ for the separation domain which aggressively abstracts information for scalability yet does not lead to false error reports. ${\\sqcup\\dagger}$ is a critical piece of a new shape analysis tool that provides an acceptable mixture of scalability and precision for industrial application. Experiments on whole Windows and Linux device drivers (firewire, pci-driver, cdrom, md, etc.) represent the first working application of shape analysis to verification of whole industrial programs.","Title: Accurate theorem proving for program verification\nYear: 2004\n\nAbstract: Symbolic software verification engines such as Slam and ESC/Java often use automatic theorem provers to implement forms of symbolic simulation. The theorem provers that are used, such as Simplify, usually combine decision procedures for the theories of uninterpreted functions, linear arithmetic, and sometimes bit vectors using techniques proposed by Nelson-Oppen or Shostak. Programming language constructs such as pointers, structures and unions are not directly supported by the provers, and are often encoded imprecisely using axioms and uninterpreted functions. In this paper we describe a more direct and accurate approach towards providing symbolic infrastructure for program verification engines. We propose the use of a theorem prover called Cogent, which provides better accuracy for ANSI-C expressions with the possibility of nested logic quantifiers. The prover's implementation is based on a machine-level interpretation of expressions into propositional logic. Cogent's translation allows the program verification tools to better reason about finite machine-level variables, bit operations, structures, unions, references, pointers and pointer arithmetic. This paper also provides experimental evidence that the proposed approach is practical when applied to industrial program verification.","Title: Ranking Function Synthesis for Bit-Vector Relations\nYear: 2013\n\nAbstract: Ranking function synthesis is a key aspect to the success of modern termination provers for imperative programs. While it\n is wellknown how to generate linear ranking functions for relations over (mathematical) integers or rationals, efficient synthesis\n of ranking functions for machine-level integers (bit-vectors) is an open problem. This is particularly relevant for the verification\n of low-level code. We propose several novel algorithms to generate ranking functions for relations over machine integers:\n a complete method based on a reduction to Presburger arithmetic, and a template-matching approach for predefined classes of\n ranking functions based on reduction to SAT- and QBF-solving. The utility of our algorithms is demonstrated on examples drawn\n from Windows device drivers.","Title: Bringing Hardware and Software Closer Together with Termination Analysis\nYear: 2007\n\nAbstract: When computers hang the root cause is usually due to termination bugs in the software that interfaces with hardware. In this talk I will discuss recent efforts to build program termination proof tools designed to find these types of bugs in systems software.","Title: At the interface of biology and computation\nYear: 2013\n\nAbstract: Representing a new class of tool for biological modeling, Bio Model Analyzer (BMA) uses sophisticated computational techniques to determine stabilization in cellular networks. This paper presents designs aimed at easing the problems that can arise when such techniques - \\'14using distinct approaches to conceptualizing networks\\'14 - are applied in biology. The work also engages with more fundamental issues being discussed in the philosophy of science and science studies. It shows how scientific ways of knowing are constituted in routine interactions with tools like BMA, where the emphasis is on the practical business at hand, even when seemingly deep conceptual problems exist. For design, this perspective refigures the frictions raised when computation is used to model biology. Rather than obstacles, they can be seen as opportunities for opening up different ways of knowing.","Title: Finding Instability in Biological Models.\nYear: 2014\n\nAbstract: The stability of biological models is an important test for establishing their soundness and accuracy. Stability in biological systems represents the ability of a robust system to always return to homeostasis. In recent work, modular approaches for proving stability have been found to be swift and scalable. If stability is however not proved, the currently available techniques apply an exhaustive search through the unstable state space to find loops. This search is frequently prohibitively computationally expensive, limiting its usefulness. Here we present a new modular approach eliminating the need for an exhaustive search for loops. Using models of biological systems we show that the technique finds loops significantly faster than brute force approaches. Furthermore, for a subset of stable systems which are resistant to modular proofs, we observe a speed up of up to 3 orders of magnitude as the exhaustive searches for loops which cause instability are avoided. With our new procedure we are able to prove instability and stability in a number of realistic biological models, including adaptation in bacterial chemotaxis, the lambda phage lysogeny/lysis switch, voltage gated channel opening and cAMP oscillations in the slime mold Dictyostelium discoideum. This new approach will support the development of new tools for biomedicine.","Title: Spatial Interpolants.\nYear: 2015\n\nAbstract: We propose Splinter, a new technique for proving properties of heap-manipulating programs that marries (1) a new separation logic-based analysis for heap reasoning with (2) an interpolation-based technique for refining heap-shape invariants with data invariants. Splinter is property directed, precise, and produces counterexample traces when a property does not hold. Using the novel notion of spatial interpolants modulo theories, Splinter can infer complex invariants over general recursive predicates, e.g., of the form all elements in a linked list are even or a binary tree is sorted. Furthermore, we treat interpolation as a black box, which gives us the freedom to encode data manipulation in any suitable theory for a given program (e.g., bit vectors, arrays, or linear arithmetic), so that our technique immediately benefits from any future advances in SMT solving and interpolation.","Title: Fairness for Infinite-State Systems.\nYear: 2015\n\nAbstract: In this paper we introduce the first known tool for symbolically proving fair-CTL properties of infinite-state integer programs. Our solution is based on a reduction to existing techniques for fairness-free CTL model checking via the use of infinite non-deterministic branching to symbolically partition fair from unfair executions. We show the viability of our approach in practice using examples drawn from device drivers and algorithms utilizing shared resources.","Title: Disproving termination with overapproximation\nYear: 2014\n\nAbstract: When disproving termination using known techniques (e.g. recurrence sets), abstractions that overapproximate the program's transition relation are unsound. In this paper we introduce live abstractions, a natural class of abstractions that can be combined with the recent concept of closed recurrence sets to soundly disprove termination. To demonstrate the practical usefulness of this new approach we show how programs with nonlinear, nondeterministic, and heap-based commands can be shown nonterminating using linear overapproximations.","Title: Faster temporal reasoning for infinite-state programs\nYear: 2014\n\nAbstract: In this paper, we describe a new symbolic model checking procedure for CTL verification of infinite-state programs. Our procedure exploits the natural decomposition of the state space given by the control-flow graph in combination with the nesting of temporal operators to optimize reasoning performed during symbolic model checking. An experimental evaluation against competing tools demonstrates that our approach not only gains orders-of-magnitude performance improvement, but also allows for scalability of temporal reasoning for larger programs.","Title: A proof engine approach to solving combinational design automation problems\nYear: 2002\n\nAbstract: There are many approaches available for solving combinational design automation problems encoded as tautology or satisfiability checks. Unfortunately there exists no single analysis that gives adequate performance for all problems of interest, and it is therefore critical to be able to combine approaches. In this paper, we present a proof engine framework where individual analyses are viewed as strategies-functions between different proof states. By defining our proof engine in such a way that we can compose strategies to form new, more powerful, strategies we achieve synergistic effects between the individual methods. The resulting framework has enabled us to develop a small set of powerful composite default strategies. We describe several strategies and their interplay; one of the strategies, variable instantiation, is new. The strength of our approach is demonstrated with experimental results showing that our default strategies can achieve up to several magnitudes of speed-up compared to BDD-based techniques and search-based satisfiability solvers such as ZCHAFF.","Title: Microprocessor specification in Hawk\nYear: 1998\n\nAbstract: Modern microprocessors require an immense investment of time and effort to create and verify, from the high-level architectural design downwards. We are exploring ways to increase the productivity of design engineers by creating a domain-specific language for specifying and simulating processor architectures. We believe that the structuring principles used in modern functional programming languages, such as static typing, parametric polymorphism, first-class functions, and lazy evaluation provide a good formalism for such a domain-specific language, and have made initial progress by creating a library on top of the functional language Haskell. We have specified the integer subset of an out-of-order, superscalar DLX microprocessor, with register-renaming, a reorder buffer, a global reservation station, multiple execution units, and speculative branch execution. Two key abstractions of this library are the signal abstract data type (ADT), which models the simulation history of a wire, and the transaction ADT, which models the state of an entire instruction as it travels through the microprocessor.","Title: On Automation Of Ctl* Verification For Infinite-State Systems\nYear: 2015\n\nAbstract: In this paper we introduce the first known fully automated tool for symbolically proving CTL* properties of (infinite-state) integer programs. The method uses an internal encoding which facilitates reasoning about the subtle interplay between the nesting of path and state temporal operators that occurs within CTL* proofs. A precondition synthesis strategy is then used over a program transformation which trades nondeterminism in the transition relation for nondeterminism explicit in variables predicting future outcomes when necessary. We show the viability of our approach in practice using examples drawn from device drivers and various industrial examples.","Title: Verifying Increasingly Expressive Temporal Logics for Infinite-State Systems.\nYear: 2017\n\nAbstract: Temporal logic is a formal system for specifying and reasoning about propositions qualified in terms of time. It offers a unified approach to program verification as it applies to both sequential and parallel programs and provides a uniform framework for describing a system at any level of abstraction. Thus, a number of automated systems have been proposed to exclusively reason about either Computation-Tree Logic (CTL) or Linear Temporal Logic (LTL) in the infinite-state setting. Unfortunately, these logics have significantly reduced expressiveness as they restrict the interplay between temporal operators and path quantifiers, thus disallowing the expression of many practical properties, for example, “along some future an event occurs infinitely often.” Contrarily, CTL*, a superset of both CTL and LTL, can facilitate the interplay between path-based and state-based reasoning. CTL* thus exclusively allows for the expressiveness of properties involving existential system stabilization and “possibility” properties. Until now, there have not existed automated systems that allow for the verification of such expressive CTL* properties over infinite-state systems. This article proposes a method capable of such a task, thus introducing the first known fully automated tool for symbolically proving CTL* properties of (infinite-state) integer programs. The method uses an internal encoding that admits reasoning about the subtle interplay between the nesting of temporal operators and path quantifiers that occurs within CTL* proofs. A program transformation is first employed that trades nondeterminism in the transition relation for nondeterminism explicit in variables predicting future outcomes when necessary. We then synthesize and quantify preconditions over the transformed program that represent program states that satisfy a CTL* formula. This article demonstrates the viability of our approach in practice, thus leading to a new class of fully-automated tools capable of proving crucial properties that no tool could previously prove. Additionally, we consider the linear-past extension to CTL* for infinite-state systems in which the past is linear and each moment in time has a unique past. We discuss the practice of this extension and how it is further supported through the use of history variables. We have implemented our approach and report our benchmarks carried out on case studies ranging from smaller programs to demonstrate the expressiveness of CTL* specifications, to larger code bases drawn from device drivers and various industrial examples.","Title: Automated formal reasoning about amazon web services (keynote)\nYear: 2017\n\nAbstract: Automatic and semiautomatic formal verification and model checking tools are now being used within AWS to find proofs that prove or disprove desired properties of key AWS components. In this session, we outline these efforts and discuss how tools are used to play and then replay found proofs of desired properties when software artifacts or networks are modified, thus helping provide security throughout the lifetime of the AWS system.","Title: Model Checking Boot Code From Aws Data Centers\nYear: 2018\n\nAbstract: This paper describes our experience with symbolic model checking in an industrial setting. We have proved that the initial boot code running in data centers at Amazon Web Services is memory safe, an essential step in establishing the security of any data center. Standard static analysis tools cannot be easily used on boot code without modification owing to issues not commonly found in higher-level code, including memory-mapped device interfaces, byte-level memory access, and linker scripts. This paper describes automated solutions to these issues and their implementation in the C Bounded Model Checker (CBMC). CBMC is now the first source-level static analysis tool to extract the memory layout described in a linker script for use in its analysis.","Title: Continuous Formal Verification Of Amazon S2n\nYear: 2018\n\nAbstract: We describe formal verification of s2n, the open source TLS implementation used in numerous Amazon services. A key aspect of this proof infrastructure is continuous checking, to ensure that properties remain proven during the lifetime of the software. At each change to the code, proofs are automatically re-established with little to no interaction from the developers. We describe the proof itself and the technical decisions that enabled integration into development.","Title: Semantic-based Automated Reasoning for AWS Access Policies using SMT\nYear: 2018\n\nAbstract: Cloud computing provides on-demand access to IT resources via the Internet. Permissions for these resources are defined by expressive access control policies. This paper presents a formalization of the Amazon Web Services (AWS) policy language and a corresponding analysis tool, called ZELKOVA, for verifying policy properties. ZELKOVA encodes the semantics of policies into SMT, compares behaviors, and verifies properties. It provides users a sound mechanism to detect misconfigurations of their policies. ZELKOVA solves a PSPACE-complete problem and is invoked many millions of times daily.","Title: Symbolic Simulation of Microprocessor Models using Type Classes in Haskell\nYear: 1999\n\nAbstract: We present a technique for doing symbolic simulation of microprocessor models in the functional programming language Haskell. We use polymorphism and the type class system, a unique feature of Haskell, to write models that work over both concrete and symbolic data. We offer this approach as an alternative to using uninterpreted constants. When the full generality of rewriting is not needed, the performance of symbolic simulation by evaluation is much faster than previously reported symbolic simulation efforts in theorem provers.","Title: Symbolic model checking for asynchronous boolean programs\nYear: 2005\n\nAbstract: Software model checking problems generally contain two different types of non-determinism: 1) non-deterministically chosen values; 2) the choice of interleaving among threads. Most modern software model checkers can handle only one source of non-determinism efficiently, but not both. This paper describes a SAT-based model checker for asynchronous Boolean programs that handles both sources effiectively. We address the first type of non-determinism with a form of symbolic execution and fix-point detection. We address the second source of non-determinism using a symbolic and dynamic partial-order reduction, which is implemented inside the SAT-solver's case-splitting algorithm. The preliminary experimental results show that the new algorithm outperforms the existing software model checkers on large benchmarks.","Title: A framework for superscalar microprocessor correctness statements\nYear: 2003\n\nAbstract: . Most verifications of superscalar, out-of-order microprocessors compare state-machine-based implementations and specifications,\n where the specification is based on the instruction-set architecture. The different efforts use a variety of correctness statements,\n implementations, and verification approaches. We present a framework for classifying correctness statements about safety properties\n of superscalar microprocessors. Our framework is independent of the implementation representation and verification approach,\n and is parameterized by the width of the processor. We characterize the relationships between the correctness statements of\n many different efforts and also illustrate how classical approaches to microprocessor verification fit within our framework.","Title: Temporal property verification as a program analysis task\nYear: 2011\n\nAbstract: We describe a reduction from temporal property verification to a program analysis problem. We produce an encoding which, with\n the use of recursion and nondeterminism, enables off-the-shelf program analysis tools to naturally perform the reasoning necessary\n for proving temporal properties (e.g. backtracking, eventuality checking, tree counterexamples for branching-time properties, abstraction refinement, etc.). Using\n examples drawn from the PostgreSQL database server, Apache web server, and Windows OS kernel, we demonstrate the practical\n viability of our work.","Title: Formal Reasoning About The Security Of Amazon Web Services\nYear: 2018\n\nAbstract: We report on the development and use of formal verification tools within Amazon Web Services (AWS) to increase the security assurance of its cloud infrastructure and to help customers secure themselves. We also discuss some remaining challenges that could inspire future research in the community.","Title: Reachability Analysis For Aws-Based Networks\nYear: 2019\n\nAbstract: Cloud services provide the ability to provision virtual networked infrastructure on demand over the Internet. The rapid growth of these virtually provisioned cloud networks has increased the demand for automated reasoning tools capable of identifying misconfigurations or security vulnerabilities. This type of automation gives customers the assurance they need to deploy sensitive workloads. It can also reduce the cost and time-to-market for regulated customers looking to establish compliance certification for cloud-based applications. In this industrial case-study, we describe a new network reachability reasoning tool, called Twos, that uses off-the-shelf automated theorem proving tools to fill this need. Twos is the foundation of a recently introduced network security analysis feature in the Amazon Inspector service now available to millions of customers building applications in the cloud. Twos is also used within Amazon Web Services (AWS) to automate the checking of compliance certification and adherence to security invariants for many AWS services that build on existing AWS networking features."],"string":"[\n \"Title: SLAYER: memory safety for systems-level code\\nYear: 2011\\n\\nAbstract: SLAyer is a program analysis tool designed to automatically prove memory safety of industrial systems code. In this paper we describe SLAyer's implementation, and its application to Windows device drivers. This paper accompanies the first release of SLAYER.\",\n \"Title: Terminator: Beyond Safety\\nYear: 2006\\n\\nAbstract: Previous symbolic software model checkers (i.e., program analysis tools based on predicate abstraction, pushdown model check- ing and iterative counterexample-guided abstraction refinement, etc.) are restricted to safety properties. Terminator is the first software model checker for termination. It is now being used to prove that device driver dispatch routines always return to their caller (or return counterexamples if they if they fail to terminate).\",\n \"Title: Proving Conditional Termination\\nYear: 2008\\n\\nAbstract: We describe a method for synthesizing reasonable underap- proximations to weakest preconditions for termination—a long-standing open problem. The paper provides experimental evidence to demonstrate the usefulness of the new procedure.\",\n \"Title: Proving program termination\\nYear: 2011\\n\\nAbstract: In contrast to popular belief, proving termination is not always impossible.\",\n \"Title: Automatically Proving Program Termination\\nYear: 2007\\n\\nAbstract: In this talk I will describe new tools that allow us to automatically prove termination and other liveness properties of software\\n systems. In particular I will discuss the Terminator program termination prover and its application to the problem of showing\\n that Windows device driver event-handling routines always eventually stop responding to events.\",\n \"Title: Verification of Boolean programs with unbounded thread creation\\nYear: 2007\\n\\nAbstract: Most symbolic software model checkers use abstraction techniques to reduce the verification of infinite-state programs to that of decidable classes. Boolean programs [T. Ball, S.K. Rajamani, Bebop: A symbolic model checker for Boolean programs, in: SPIN 00, in: Lecture Notes in Computer Science, vol. 1885, Springer, 2000, pp. 113-130] are the most popular representation for these abstractions. Unfortunately, today's symbolic software model checkers are limited to the analysis of sequential programs due to the fact that reachability in Boolean programs with unbounded thread creation is undecidable. We address this limitation with a novel algorithm for over-approximating reachability in Boolean programs with unbounded thread creation. Although the Boolean programs are not of finite state, the algorithm always reaches a fix-point. The fixed points are detected by projecting the state of the threads to the globally visible parts, which are finite.\",\n \"Title: Proving Termination by Divergence.\\nYear: 2007\\n\\nAbstract: A key challenge for software engineering is to learn how to reconcile the formal world of the machine and its software with the non-formal real world. In this paper, we discuss elements of Problem Oriented Software Engineering (POSE), an approach that ...\",\n \"Title: Tractable reasoning in a fragment of separation logic\\nYear: 2011\\n\\nAbstract: In 2004, Berdine, Calcagno and O'Hearn introduced a fragment of separation logic that allows for reasoning about programs with pointers and linked lists. They showed that entailment in this fragment is in coNP, but the precise complexity of this problem has been open since. In this paper, we show that the problem can actually be solved in polynomial time. To this end, we represent separation logic formulae as graphs and show that every satisfiable formula is equivalent to one whose graph is in a particular normal form. Entailment between two such formulae then reduces to a graph homomorphism problem. We also discuss natural syntactic extensions that render entailment intractable.\",\n \"Title: Advances in Program Termination and Liveness\\nYear: 2009\\n\\nAbstract: Recent research advances now allow us to automatically prove termination and other liveness properties of many industrial programs. In cases where the desired property does not hold for all inputs, tools can be used to synthesize a precondition on the inputs under which the property does hold. In this tutorial I will describe these recent advances and discuss our efforts to apply termination analysis to industrial software.\",\n \"Title: Proving termination of nonlinear command sequences.\\nYear: 2013\\n\\nAbstract: We describe a simple and efficient algorithm for proving the termination of a class of loops with nonlinear assignments to variables. The method is based on divergence testing for each variable in the cone-of-influence of the loop’s condition. The analysis allows us to automatically prove the termination of loops that cannot be handled using previous techniques. We also describe a method for integrating our nonlinear termination proving technique into a larger termination proving framework that depends on linear reasoning.\",\n \"Title: Automatic termination proofs for programs with shape-shifting heaps\\nYear: 2006\\n\\nAbstract: We describe a new program termination analysis designed to handle imperative programs whose termination depends on the mutation of the program's heap. We first describe how an abstract interpretation can be used to construct a finite number of relations which, if each is well-founded, implies termination. We then give an abstract interpretation based on separation logic formulæwhich tracks the depths of pieces of heaps. Finally, we combine these two techniques to produce an automatic termination prover. We show that the analysis is able to prove the termination of loops extracted from Windows device drivers that could not be proved terminating before by other means; we also discuss a previously unknown bug found with the analysis.\",\n \"Title: A Framework for Microprocessor Correctness Statements\\nYear: 2001\\n\\nAbstract: Most verifications of out-of-order microprocessors compare state-machine-based implementations and specifications, where the specification is based on the instruction-set architecture. The different efforts use a variety of correctness statements, implementations, and verification approaches. We present a framework for classifying correctness statements about safety that is independent of implementation representation and verification approach. We characterize the relationships between the different statements and illustrate how existing and classical approaches fit within this framework.\",\n \"Title: Combining Stream-Based and State-Based Verification Techniques\\nYear: 2000\\n\\nAbstract: Algebraic verification techniques manipulate the structure of a circuit while preserving its behavior. Algorithmic verification techniques verify properties about the behavior of a circuit. These two techniques have complementary strengths: algebraic techniques are largely independent of the size of the state space, and algorithmic techniques are highly automated. It is desirable to exploit both in the same verification. However, algebraic techniques often use stream-based models of circuits, while algorithmic techniques use state-based models. We prove the consistency of stream- and state-based interpretations of circuit models, and show how stream-based verification results can be used hand-in-hand with state-based verification results. Our approach allows us to combine stream-based algebraic rewriting and state-based reasoning, using SMV and SVC, to verify a pipelined microarchitecture with speculative execution.\",\n \"Title: Shape analysis for composite data structures\\nYear: 2007\\n\\nAbstract: We propose a shape analysis that adapts to some of the complex composite data structures found in industrial systems-level programs. Examples of such data structures include \\\"cyclic doubly-linked lists of acyclic singly-linked lists\\\", \\\"singly-linked lists of cyclic doubly-linked lists with back-pointers to head nodes\\\", etc. The analysis introduces the use of generic higher-order inductive predicates describing spatial relationships together with a method of synthesizing new parameterized spatial predicates which can be used in combination with the higher-order predicates. In order to evaluate the proposed approach for realistic programs we have performed experiments on examples drawn from device drivers: the analysis proved safety of the data structure manipulation of several routines belonging to an IEEE 1394 (firewire) driver, and also found several previously unknown memory safety bugs.\",\n \"Title: Local reasoning for storable locks and threads\\nYear: 2007\\n\\nAbstract: We present a resource oriented program logic that is able to reason about concurrent heap-manipulating programs with unbounded numbers of dynamically-allocated locks and threads. The logic is inspired by concurrent separation logic, but handles these more realistic concurrency primitives. We demonstrate that the proposed logic allows local reasoning about programs for which there exists a notion of dynamic ownership of heap parts by locks and threads.\",\n \"Title: Refining Approximations in Software Predicate Abstraction\\nYear: 2004\\n\\nAbstract: Predicate abstraction is an automatic technique that can be used to find abstract models of large or infinite-state systems. In tools like SLAM, where predicate abstraction is applied to software model checking, a number of heuristic approximations must be used to improve the performance of computing an abstraction from a set of predicates. For this reason, SLAM can sometimes reach a state in which it is not able to further refine the abstraction. In this paper we report on an application of Das & Dill's algorithm for predicate abstraction refinement. SLAM now uses this strategy lazily to recover precision in cases where the abstractions generated are too coarse. We describe how we have extended Das & Dill's original algorithm for use in software model checking. Our extension supports procedures, threads, and potential pointer aliasing. We also present results from experiments with SLAM on device driver sources from the Windows operating system.\",\n \"Title: BMA: visual tool for modeling and analyzing biological networks\\nYear: 2012\\n\\nAbstract: BioModel Analyzer (bma) is a tool for modeling and analyzing biological networks. Designed with a lightweight graphical user interface, the tool facilitates usage for biologists with no previous knowledge in programming or formal methods. The current implementation analyzes systems to establish stabilization. The results of the analysis--whether they be proofs or counterexamples--are represented visually. This paper describes the approach to modeling used in bma and also notes soon-to-be-released extensions to the tool.\",\n \"Title: On embedding a microarchitectural design language within Haskell\\nYear: 1999\\n\\nAbstract: Based on our experience with modelling and verifying microarchitectural designs within Haskell, this paper examines our use of Haskell as host for an embedded language. In particular, we highlight our use of Haskell's lazy lists, type classes, lazy state monad, and unsafe Perform I0, and point to several areas where Haskell could be improved in the future. We end with an example of a benefit gained by bringing the functional perspective to microarchitectural modelling.\",\n \"Title: Predicate abstraction via symbolic decision procedures\\nYear: 2005\\n\\nAbstract: We present a new approach for performing predicate abstraction based on\\nsymbolic decision procedures. Intuitively, a symbolic decision procedure for a\\ntheory takes a set of predicates in the theory and symbolically executes a\\ndecision procedure on all the subsets over the set of predicates. The result of\\nthe symbolic decision procedure is a shared expression (represented by a\\ndirected acyclic graph) that implicitly represents the answer to a predicate\\nabstraction query.\\n We present symbolic decision procedures for the logic of Equality and\\nUninterpreted Functions (EUF) and Difference logic (DIFF) and show that these\\nprocedures run in pseudo-polynomial (rather than exponential) time. We then\\nprovide a method to construct symbolic decision procedures for simple mixed\\ntheories (including the two theories mentioned above) using an extension of the\\nNelson-Oppen combination method. We present preliminary evaluation of our\\nProcedure on predicate abstraction benchmarks from device driver verification\\nin SLAM.\",\n \"Title: Using stålmarck’s algorithm to prove inequalities\\nYear: 2005\\n\\nAbstract: Stålmarck’s 1-saturation algorithm is an incomplete but fast method for computing partial equivalence relations over propositional formulae. Aside from anecdotal evidence, until now little has been known about what it can prove. In this paper we characterize a set of formulae with bitvector-inequalities for which 1-saturation is sufficient to prove unsatisfiability. This result has application to fast predicate abstraction for software with fixed-width bit-vectors.\",\n \"Title: Finding heap-bounds for hardware synthesis\\nYear: 2009\\n\\nAbstract: Abstract—Dynamically allocated and manipulated data struc- tures cannot be translated into hardware unless there is an upper bound on the amount,of memory,the program,uses during all executions. This bound,can depend on the generic parameters to the program, i.e., program inputs that are instantiated at synthesis time. We propose a constraint based method,for the discovery of memory usage bounds, which leads to the first- known,C-to-gates hardware synthesis supporting programs with non-trivial use of dynamically allocated memory, e.g., linked lists maintained withmalloc,andfree. We illustrate the practicality of our tool on a range of examples. I. I NTRODUCTION C-to-gates synthesis promises to bring the power,of hard- ware based acceleration to mainstream,programmers,and to radically increase the productivity of digital designers [ 17]. However, today’s C-to-gates synthesis tools do not support one of the most powerful and widely used features of high-level programming,in C—dynamically,allocated data structures. Thus, with today’s tools we usually cannot synthesize gates from off-the-shelf C-based software. The support for dynamic memory,abstraction remains,an on-going research problem\",\n \"Title: Better termination proving through cooperation\\nYear: 2013\\n\\nAbstract: One of the difficulties of proving program termination is managing the subtle interplay between the finding of a termination argument and the finding of the argument's supporting invariant. In this paper we propose a new mechanism that facilitates better cooperation between these two types of reasoning. In an experimental evaluation we find that our new method leads to dramatic performance improvements.\",\n \"Title: Taming the Unbounded for Hardware Synthesis\\nYear: 2009\\n\\nAbstract: The difficulty with compiling software to hardware is one of finding a priori bounds on the potentially unbounded resources used by programs: memory and time. New approaches now allow us to synthesize bounds on these resources, leading to new high-level hardware synthesis tools.\",\n \"Title: Automatically Proving Concurrent Programs Correct\\nYear: 2007\\n\\nAbstract: This talk will describe new advances that allow us to automatically prove both liveness properties and heap-shape properties of concurrent programs. The talk will focus on recent thread-modular extensions to the program termination prover TERMINATOR and shape analysis tool SLAyer and their application to Windows device drivers.\",\n \"Title: Arithmetic Strengthening for Shape Analysis\\nYear: 2007\\n\\nAbstract: Shape analyses are often imprecise in their numerical reason- ing, whereas numerical static analyses are often largely unaware of the shape of a program's heap. In this paper we propose a lazy method of combining a shape analysis based on separation logic with an arbitrary arithmetic analysis. When potentially spurious counterexamples are re- ported by our shape analysis, the method constructs a purely arithmetic program whose traces over-approximate the set of counterexample traces. It then uses this arithmetic program together with the arithmetic analy- sis to construct a refinement for the shape analysis. Our method is aimed at proving properties that require comprehensive reasoning about heaps together with more targeted arithmetic reasoning. Given a sucient pre- condition, our technique can automatically prove memory safety of pro- grams whose error-free operation depends on a combination of shape, size, and integer invariants. We have implemented our algorithm and tested it on a number of common list routines using a variety of arith- metic analysis tools for refinement.\",\n \"Title: Proving Stabilization of Biological Systems\\nYear: 2011\\n\\nAbstract: We describe an ecient procedure for proving stabilization of biological systems modeled as qualitative networks. For scalability, our procedure uses modular proof techniques, where state-space exploration is applied only locally to small pieces of the system rather than the en- tire system as a whole. Our procedure exploits the observation that, in practice, the form of modular proofs required can be restricted to a very limited set. Using our new procedure, we have solved a number of chal- lenging published examples, including a 3-D model of the mammalian epidermis, a model of metabolic networks operating in type-2 diabetes, and a model of fate determination of vulval precursor cells in the C. ele- gans worm. Our results show many orders of magnitude speedup in cases where previous stabilization proving techniques were known to succeed, and new results in cases where tools had previously failed.\",\n \"Title: Ramsey vs. lexicographic termination proving\\nYear: 2013\\n\\nAbstract: Termination proving has traditionally been based on the search for (possibly lexicographic) ranking functions. In recent years, however, the discovery of termination proof techniques based on Ramsey's theorem have led to new automation strategies, e.g. size-change, or iterative reductions from termination to safety. In this paper we revisit the decision to use Ramsey-based termination arguments in the iterative approach. We describe a new iterative termination proving procedure that instead searches for lexicographic termination arguments. Using experimental evidence we show that this new method leads to dramatic speedups.\",\n \"Title: Reasoning about nondeterminism in programs\\nYear: 2013\\n\\nAbstract: Branching-time temporal logics (e.g. CTL, CTL*, modal mu-calculus) allow us to ask sophisticated questions about the nondeterminism that appears in systems. Applications of this type of reasoning include planning, games, security analysis, disproving, precondition synthesis, environment synthesis, etc. Unfortunately, existing automatic branching-time verification tools have limitations that have traditionally restricted their applicability (e.g. push-down systems only, universal path quantifiers only, etc). In this paper we introduce an automation strategy that lifts many of these previous restrictions. Our method works reliably for properties with non-trivial mixtures of universal and existential modal operators. Furthermore, our approach is designed to support (possibly infinite-state) programs. The basis of our approach is the observation that existential reasoning can be reduced to universal reasoning if the system's state-space is appropriately restricted. This restriction on the state-space must meet a constraint derived from recent work on proving non-termination. The observation leads to a new route for implementation based on existing tools. To demonstrate the practical viability of our approach, we report on the results applying our preliminary implementation to a set of benchmarks drawn from the Windows operating system, the PostgreSQL database server, SoftUpdates patching system, as well as other hand-crafted examples.\",\n \"Title: Precision and the Conjunction Rule in Concurrent Separation Logic\\nYear: 2011\\n\\nAbstract: Concurrent separation logic is a Hoare logic for modular reasoning about concurrent heap-manipulating programs synchronising via locks. It achieves modular reasoning by partitioning the program state into thread-local and lock-protected parts, and assigning resource invariants to the latter. Surprisingly, the logic is unsound unless resource invariants are precise, i.e., unambiguously carve out an area of the heap. The counterexample showing the unsoundness involves the conjunction rule. However, to date it has been an open question whether concurrent separation logic without the conjunction rule is sound when the restriction on resource invariants is dropped: all the published proofs have the precision restriction baked in. In this paper we present a single proof that shows the soundness of the logic with imprecise resource invariants, but without the conjunction rule, as well as its classical version, where resource invariants are required to be precise and the conjunction rule is included. Our proof yields a precise and direct formulation of O@?Hearn@?s Separation Property and provides a semantic analysis of the logic that is much more elementary than previous proofs.\",\n \"Title: SoftMC 2003: Workshop on Software Model Checking\\nYear: 2003\\n\\nAbstract: This volume contains the Proceedings of the 2nd Workshop on Software Model Checking, which was held on 14 July 2003 in Boulder, Colorado. The Workshop was a satellite event of the Conference on Computer Aided Verification (CAV) 2003.\",\n \"Title: Repair of boolean programs with an application to c\\nYear: 2006\\n\\nAbstract: We show how to find and fix faults in Boolean programs by extending the program to a game. In the game, the protagonist can select an alternative implementation for an incorrect statement. If the protagonist can do so successfully using a memoryless strategy that does not depend on the stack contents, we have found a correction for the Boolean program. We present a symbolic algorithm that localizes possibly faulty statements and provides corrections. If the Boolean program is an abstraction of a C program, the repair for the Boolean program suggests a repair for the original C program. This yields a correct but incomplete approach to repairing C programs. We have applied this approach to Boolean programs that are produced as abstractions by SLAM and have thus successfully patched several faulty Windows device drivers.\",\n \"Title: Over-Approximating Boolean Programs with Unbounded Thread Creation\\nYear: 2006\\n\\nAbstract: This paper describes a symbolic algorithm for overapproximating reachability in Boolean programs with unbounded thread creation. The fix-point is detected by projecting the state of the threads to the globally visible parts, which are finite. Our algorithm models recursion by over-approximating the call stack that contains the return locations of recursive function calls, as reachability is undecidable in this case. The algorithm may obtain spurious counterexamples, which are removed iteratively by means of an abstraction refinement loop. Experiments show that the symbolic algorithm for unbounded thread creation scales to large abstract models.\",\n \"Title: Summarization for termination: no return!\\nYear: 2009\\n\\nAbstract: We propose a program analysis method for proving termination of recursive programs. The analysis is based on a reduction of termination to two separate problems: reachability of recursive programs, and termination of non-recursive programs. Our reduction works through a program transformation that modifies the call sites and removes return edges. In the new, non-recursive program, a procedure call may non-deterministically enter the procedure body (which means that it will never return) or apply a summary statement.\",\n \"Title: Software engineering and formal methods\\nYear: 2008\\n\\nAbstract: The answer to software reliability concerns may lie in formal methods.\",\n \"Title: Formal Verification of Explicitly Parallel Microprocessors\\nYear: 1999\\n\\nAbstract: The trend in microprocessor design is to extend instruction-set architectures with features--such as parallelism annotations, predication, speculative memory access, or multimedia instructions--that allow the compiler or programmer to express more instruction-level parallelism than the microarchitecture is willing to derive. In this paper we show how these instruction-set extensions can be put to use when formally verifying the correctness of a microarchitectural model. Inspired by Intel's IA-64, we develop an explicitly parallel instruction-set architecture and a clustered microarchitectural model. We then describe how to formally verify that the model implements the instruction set. The contribution of this paper is a specification and verification method that facilitates the decomposition of microarchitectural correctness proofs using instruction-set extensions.\",\n \"Title: Interprocedural shape analysis with separated heap abstractions\\nYear: 2006\\n\\nAbstract: We describe an interprocedural shape analysis that makes use of spatial locality (i.e. the fact that most procedures modify only a small subset of the heap) in its representation of abstract states. Instead of tracking reachability information directly and aliasing information indirectly, our representation tracks reachability indirectly and aliasing directly. Computing the effect of procedure calls and returns on an abstract state is easy because the representation exhibits spatial locality mirroring the locality that is present in the concrete semantics. The benefits of this approach include improved speed, support for programs that deallocate memory, the handling of bounded numbers of heap cutpoints, and support for cyclic and shared data structures.\",\n \"Title: Cogent: accurate theorem proving for program verification\\nYear: 2005\\n\\nAbstract: Many symbolic software verification engines such as Slam and ESC/Java rely on automatic theorem provers. The existing theorem provers, such as Simplify, lack precise support for important programming language constructs such as pointers, structures and unions. This paper describes a theorem prover, Cogent, that accurately supports all ANSI-C expressions. The prover's implementation is based on a machine-level interpretation of expressions into propositional logic, and supports finite machine-level variables, bit operations, structures, unions, references, pointers and pointer arithmetic. When used by Slam during the model checking of over 300 benchmarks, Cogent's improved accuracy reduced the number of Slam timeouts by half, increased the number of true errors found, and decreased the number of false errors.\",\n \"Title: Scalable Shape Analysis for Systems Code\\nYear: 2008\\n\\nAbstract: Pointer safety faults in device drivers are one of the leading causes of crashes in operating systems code. In principle, shape analysis tools can be used to prove the absence of this type of error. In practice, however, shape analysis is not used due to the unacceptable mixture of scalability and precision provided by existing tools. In this paper we report on a new join operation ${\\\\sqcup\\\\dagger}$ for the separation domain which aggressively abstracts information for scalability yet does not lead to false error reports. ${\\\\sqcup\\\\dagger}$ is a critical piece of a new shape analysis tool that provides an acceptable mixture of scalability and precision for industrial application. Experiments on whole Windows and Linux device drivers (firewire, pci-driver, cdrom, md, etc.) represent the first working application of shape analysis to verification of whole industrial programs.\",\n \"Title: Accurate theorem proving for program verification\\nYear: 2004\\n\\nAbstract: Symbolic software verification engines such as Slam and ESC/Java often use automatic theorem provers to implement forms of symbolic simulation. The theorem provers that are used, such as Simplify, usually combine decision procedures for the theories of uninterpreted functions, linear arithmetic, and sometimes bit vectors using techniques proposed by Nelson-Oppen or Shostak. Programming language constructs such as pointers, structures and unions are not directly supported by the provers, and are often encoded imprecisely using axioms and uninterpreted functions. In this paper we describe a more direct and accurate approach towards providing symbolic infrastructure for program verification engines. We propose the use of a theorem prover called Cogent, which provides better accuracy for ANSI-C expressions with the possibility of nested logic quantifiers. The prover's implementation is based on a machine-level interpretation of expressions into propositional logic. Cogent's translation allows the program verification tools to better reason about finite machine-level variables, bit operations, structures, unions, references, pointers and pointer arithmetic. This paper also provides experimental evidence that the proposed approach is practical when applied to industrial program verification.\",\n \"Title: Ranking Function Synthesis for Bit-Vector Relations\\nYear: 2013\\n\\nAbstract: Ranking function synthesis is a key aspect to the success of modern termination provers for imperative programs. While it\\n is wellknown how to generate linear ranking functions for relations over (mathematical) integers or rationals, efficient synthesis\\n of ranking functions for machine-level integers (bit-vectors) is an open problem. This is particularly relevant for the verification\\n of low-level code. We propose several novel algorithms to generate ranking functions for relations over machine integers:\\n a complete method based on a reduction to Presburger arithmetic, and a template-matching approach for predefined classes of\\n ranking functions based on reduction to SAT- and QBF-solving. The utility of our algorithms is demonstrated on examples drawn\\n from Windows device drivers.\",\n \"Title: Bringing Hardware and Software Closer Together with Termination Analysis\\nYear: 2007\\n\\nAbstract: When computers hang the root cause is usually due to termination bugs in the software that interfaces with hardware. In this talk I will discuss recent efforts to build program termination proof tools designed to find these types of bugs in systems software.\",\n \"Title: At the interface of biology and computation\\nYear: 2013\\n\\nAbstract: Representing a new class of tool for biological modeling, Bio Model Analyzer (BMA) uses sophisticated computational techniques to determine stabilization in cellular networks. This paper presents designs aimed at easing the problems that can arise when such techniques - \\\\'14using distinct approaches to conceptualizing networks\\\\'14 - are applied in biology. The work also engages with more fundamental issues being discussed in the philosophy of science and science studies. It shows how scientific ways of knowing are constituted in routine interactions with tools like BMA, where the emphasis is on the practical business at hand, even when seemingly deep conceptual problems exist. For design, this perspective refigures the frictions raised when computation is used to model biology. Rather than obstacles, they can be seen as opportunities for opening up different ways of knowing.\",\n \"Title: Finding Instability in Biological Models.\\nYear: 2014\\n\\nAbstract: The stability of biological models is an important test for establishing their soundness and accuracy. Stability in biological systems represents the ability of a robust system to always return to homeostasis. In recent work, modular approaches for proving stability have been found to be swift and scalable. If stability is however not proved, the currently available techniques apply an exhaustive search through the unstable state space to find loops. This search is frequently prohibitively computationally expensive, limiting its usefulness. Here we present a new modular approach eliminating the need for an exhaustive search for loops. Using models of biological systems we show that the technique finds loops significantly faster than brute force approaches. Furthermore, for a subset of stable systems which are resistant to modular proofs, we observe a speed up of up to 3 orders of magnitude as the exhaustive searches for loops which cause instability are avoided. With our new procedure we are able to prove instability and stability in a number of realistic biological models, including adaptation in bacterial chemotaxis, the lambda phage lysogeny/lysis switch, voltage gated channel opening and cAMP oscillations in the slime mold Dictyostelium discoideum. This new approach will support the development of new tools for biomedicine.\",\n \"Title: Spatial Interpolants.\\nYear: 2015\\n\\nAbstract: We propose Splinter, a new technique for proving properties of heap-manipulating programs that marries (1) a new separation logic-based analysis for heap reasoning with (2) an interpolation-based technique for refining heap-shape invariants with data invariants. Splinter is property directed, precise, and produces counterexample traces when a property does not hold. Using the novel notion of spatial interpolants modulo theories, Splinter can infer complex invariants over general recursive predicates, e.g., of the form all elements in a linked list are even or a binary tree is sorted. Furthermore, we treat interpolation as a black box, which gives us the freedom to encode data manipulation in any suitable theory for a given program (e.g., bit vectors, arrays, or linear arithmetic), so that our technique immediately benefits from any future advances in SMT solving and interpolation.\",\n \"Title: Fairness for Infinite-State Systems.\\nYear: 2015\\n\\nAbstract: In this paper we introduce the first known tool for symbolically proving fair-CTL properties of infinite-state integer programs. Our solution is based on a reduction to existing techniques for fairness-free CTL model checking via the use of infinite non-deterministic branching to symbolically partition fair from unfair executions. We show the viability of our approach in practice using examples drawn from device drivers and algorithms utilizing shared resources.\",\n \"Title: Disproving termination with overapproximation\\nYear: 2014\\n\\nAbstract: When disproving termination using known techniques (e.g. recurrence sets), abstractions that overapproximate the program's transition relation are unsound. In this paper we introduce live abstractions, a natural class of abstractions that can be combined with the recent concept of closed recurrence sets to soundly disprove termination. To demonstrate the practical usefulness of this new approach we show how programs with nonlinear, nondeterministic, and heap-based commands can be shown nonterminating using linear overapproximations.\",\n \"Title: Faster temporal reasoning for infinite-state programs\\nYear: 2014\\n\\nAbstract: In this paper, we describe a new symbolic model checking procedure for CTL verification of infinite-state programs. Our procedure exploits the natural decomposition of the state space given by the control-flow graph in combination with the nesting of temporal operators to optimize reasoning performed during symbolic model checking. An experimental evaluation against competing tools demonstrates that our approach not only gains orders-of-magnitude performance improvement, but also allows for scalability of temporal reasoning for larger programs.\",\n \"Title: A proof engine approach to solving combinational design automation problems\\nYear: 2002\\n\\nAbstract: There are many approaches available for solving combinational design automation problems encoded as tautology or satisfiability checks. Unfortunately there exists no single analysis that gives adequate performance for all problems of interest, and it is therefore critical to be able to combine approaches. In this paper, we present a proof engine framework where individual analyses are viewed as strategies-functions between different proof states. By defining our proof engine in such a way that we can compose strategies to form new, more powerful, strategies we achieve synergistic effects between the individual methods. The resulting framework has enabled us to develop a small set of powerful composite default strategies. We describe several strategies and their interplay; one of the strategies, variable instantiation, is new. The strength of our approach is demonstrated with experimental results showing that our default strategies can achieve up to several magnitudes of speed-up compared to BDD-based techniques and search-based satisfiability solvers such as ZCHAFF.\",\n \"Title: Microprocessor specification in Hawk\\nYear: 1998\\n\\nAbstract: Modern microprocessors require an immense investment of time and effort to create and verify, from the high-level architectural design downwards. We are exploring ways to increase the productivity of design engineers by creating a domain-specific language for specifying and simulating processor architectures. We believe that the structuring principles used in modern functional programming languages, such as static typing, parametric polymorphism, first-class functions, and lazy evaluation provide a good formalism for such a domain-specific language, and have made initial progress by creating a library on top of the functional language Haskell. We have specified the integer subset of an out-of-order, superscalar DLX microprocessor, with register-renaming, a reorder buffer, a global reservation station, multiple execution units, and speculative branch execution. Two key abstractions of this library are the signal abstract data type (ADT), which models the simulation history of a wire, and the transaction ADT, which models the state of an entire instruction as it travels through the microprocessor.\",\n \"Title: On Automation Of Ctl* Verification For Infinite-State Systems\\nYear: 2015\\n\\nAbstract: In this paper we introduce the first known fully automated tool for symbolically proving CTL* properties of (infinite-state) integer programs. The method uses an internal encoding which facilitates reasoning about the subtle interplay between the nesting of path and state temporal operators that occurs within CTL* proofs. A precondition synthesis strategy is then used over a program transformation which trades nondeterminism in the transition relation for nondeterminism explicit in variables predicting future outcomes when necessary. We show the viability of our approach in practice using examples drawn from device drivers and various industrial examples.\",\n \"Title: Verifying Increasingly Expressive Temporal Logics for Infinite-State Systems.\\nYear: 2017\\n\\nAbstract: Temporal logic is a formal system for specifying and reasoning about propositions qualified in terms of time. It offers a unified approach to program verification as it applies to both sequential and parallel programs and provides a uniform framework for describing a system at any level of abstraction. Thus, a number of automated systems have been proposed to exclusively reason about either Computation-Tree Logic (CTL) or Linear Temporal Logic (LTL) in the infinite-state setting. Unfortunately, these logics have significantly reduced expressiveness as they restrict the interplay between temporal operators and path quantifiers, thus disallowing the expression of many practical properties, for example, “along some future an event occurs infinitely often.” Contrarily, CTL*, a superset of both CTL and LTL, can facilitate the interplay between path-based and state-based reasoning. CTL* thus exclusively allows for the expressiveness of properties involving existential system stabilization and “possibility” properties. Until now, there have not existed automated systems that allow for the verification of such expressive CTL* properties over infinite-state systems. This article proposes a method capable of such a task, thus introducing the first known fully automated tool for symbolically proving CTL* properties of (infinite-state) integer programs. The method uses an internal encoding that admits reasoning about the subtle interplay between the nesting of temporal operators and path quantifiers that occurs within CTL* proofs. A program transformation is first employed that trades nondeterminism in the transition relation for nondeterminism explicit in variables predicting future outcomes when necessary. We then synthesize and quantify preconditions over the transformed program that represent program states that satisfy a CTL* formula. This article demonstrates the viability of our approach in practice, thus leading to a new class of fully-automated tools capable of proving crucial properties that no tool could previously prove. Additionally, we consider the linear-past extension to CTL* for infinite-state systems in which the past is linear and each moment in time has a unique past. We discuss the practice of this extension and how it is further supported through the use of history variables. We have implemented our approach and report our benchmarks carried out on case studies ranging from smaller programs to demonstrate the expressiveness of CTL* specifications, to larger code bases drawn from device drivers and various industrial examples.\",\n \"Title: Automated formal reasoning about amazon web services (keynote)\\nYear: 2017\\n\\nAbstract: Automatic and semiautomatic formal verification and model checking tools are now being used within AWS to find proofs that prove or disprove desired properties of key AWS components. In this session, we outline these efforts and discuss how tools are used to play and then replay found proofs of desired properties when software artifacts or networks are modified, thus helping provide security throughout the lifetime of the AWS system.\",\n \"Title: Model Checking Boot Code From Aws Data Centers\\nYear: 2018\\n\\nAbstract: This paper describes our experience with symbolic model checking in an industrial setting. We have proved that the initial boot code running in data centers at Amazon Web Services is memory safe, an essential step in establishing the security of any data center. Standard static analysis tools cannot be easily used on boot code without modification owing to issues not commonly found in higher-level code, including memory-mapped device interfaces, byte-level memory access, and linker scripts. This paper describes automated solutions to these issues and their implementation in the C Bounded Model Checker (CBMC). CBMC is now the first source-level static analysis tool to extract the memory layout described in a linker script for use in its analysis.\",\n \"Title: Continuous Formal Verification Of Amazon S2n\\nYear: 2018\\n\\nAbstract: We describe formal verification of s2n, the open source TLS implementation used in numerous Amazon services. A key aspect of this proof infrastructure is continuous checking, to ensure that properties remain proven during the lifetime of the software. At each change to the code, proofs are automatically re-established with little to no interaction from the developers. We describe the proof itself and the technical decisions that enabled integration into development.\",\n \"Title: Semantic-based Automated Reasoning for AWS Access Policies using SMT\\nYear: 2018\\n\\nAbstract: Cloud computing provides on-demand access to IT resources via the Internet. Permissions for these resources are defined by expressive access control policies. This paper presents a formalization of the Amazon Web Services (AWS) policy language and a corresponding analysis tool, called ZELKOVA, for verifying policy properties. ZELKOVA encodes the semantics of policies into SMT, compares behaviors, and verifies properties. It provides users a sound mechanism to detect misconfigurations of their policies. ZELKOVA solves a PSPACE-complete problem and is invoked many millions of times daily.\",\n \"Title: Symbolic Simulation of Microprocessor Models using Type Classes in Haskell\\nYear: 1999\\n\\nAbstract: We present a technique for doing symbolic simulation of microprocessor models in the functional programming language Haskell. We use polymorphism and the type class system, a unique feature of Haskell, to write models that work over both concrete and symbolic data. We offer this approach as an alternative to using uninterpreted constants. When the full generality of rewriting is not needed, the performance of symbolic simulation by evaluation is much faster than previously reported symbolic simulation efforts in theorem provers.\",\n \"Title: Symbolic model checking for asynchronous boolean programs\\nYear: 2005\\n\\nAbstract: Software model checking problems generally contain two different types of non-determinism: 1) non-deterministically chosen values; 2) the choice of interleaving among threads. Most modern software model checkers can handle only one source of non-determinism efficiently, but not both. This paper describes a SAT-based model checker for asynchronous Boolean programs that handles both sources effiectively. We address the first type of non-determinism with a form of symbolic execution and fix-point detection. We address the second source of non-determinism using a symbolic and dynamic partial-order reduction, which is implemented inside the SAT-solver's case-splitting algorithm. The preliminary experimental results show that the new algorithm outperforms the existing software model checkers on large benchmarks.\",\n \"Title: A framework for superscalar microprocessor correctness statements\\nYear: 2003\\n\\nAbstract: . Most verifications of superscalar, out-of-order microprocessors compare state-machine-based implementations and specifications,\\n where the specification is based on the instruction-set architecture. The different efforts use a variety of correctness statements,\\n implementations, and verification approaches. We present a framework for classifying correctness statements about safety properties\\n of superscalar microprocessors. Our framework is independent of the implementation representation and verification approach,\\n and is parameterized by the width of the processor. We characterize the relationships between the correctness statements of\\n many different efforts and also illustrate how classical approaches to microprocessor verification fit within our framework.\",\n \"Title: Temporal property verification as a program analysis task\\nYear: 2011\\n\\nAbstract: We describe a reduction from temporal property verification to a program analysis problem. We produce an encoding which, with\\n the use of recursion and nondeterminism, enables off-the-shelf program analysis tools to naturally perform the reasoning necessary\\n for proving temporal properties (e.g. backtracking, eventuality checking, tree counterexamples for branching-time properties, abstraction refinement, etc.). Using\\n examples drawn from the PostgreSQL database server, Apache web server, and Windows OS kernel, we demonstrate the practical\\n viability of our work.\",\n \"Title: Formal Reasoning About The Security Of Amazon Web Services\\nYear: 2018\\n\\nAbstract: We report on the development and use of formal verification tools within Amazon Web Services (AWS) to increase the security assurance of its cloud infrastructure and to help customers secure themselves. We also discuss some remaining challenges that could inspire future research in the community.\",\n \"Title: Reachability Analysis For Aws-Based Networks\\nYear: 2019\\n\\nAbstract: Cloud services provide the ability to provision virtual networked infrastructure on demand over the Internet. The rapid growth of these virtually provisioned cloud networks has increased the demand for automated reasoning tools capable of identifying misconfigurations or security vulnerabilities. This type of automation gives customers the assurance they need to deploy sensitive workloads. It can also reduce the cost and time-to-market for regulated customers looking to establish compliance certification for cloud-based applications. In this industrial case-study, we describe a new network reachability reasoning tool, called Twos, that uses off-the-shelf automated theorem proving tools to fill this need. Twos is the foundation of a recently introduced network security analysis feature in the Amazon Inspector service now available to millions of customers building applications in the cloud. Twos is also used within Amazon Web Services (AWS) to automate the checking of compliance certification and adherence to security invariants for many AWS services that build on existing AWS networking features.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":61,"string":"61"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13377,"string":"13,377"}}},{"rowIdx":13378,"cells":{"question_id":{"kind":"string","value":"Walter Cazzola"},"question":{"kind":"string","value":"Generate an abstract for the title \"Gradually Learning Programming Supported by a Growable Programming Language\" using the following items: 1. Learning programming difficulties\n2. Mainstream programming languages\n3. Issue with language constructs\n4. Problem solving and pre-cooked solutions\n5. Limiting language constructs for experimentation"},"answer":{"kind":"string","value":"Learning programming is a difficult task. Such difficulties depends on the chosen programming language and the exposure to the single programming concept. Mainstream programming languages such as Java, C and C++ are the most popular. But their innate complexity and the complexity of their tools risk to divert students' attention from the key point of learning appropriate programming techniques in general. Students that approach learning programming tend to focus on learning the programming language since it looks more practicable. The prominent issue lies within the core components of these languages: each programming language consists of many different features-such as control flow, variable definition, and so on-, each bound to a different group of constructs of the language. Due to their strict intertwining, the students are forced to keep up with a considerable quantity of unknown constructs and concepts since the beginning. This issue aggravates if we consider that many of these constructs are not meant to be fully explained until much further in the course, or worse, never. Also support tools, as IDEs, do not help the teacher in the compartmentalization of the programming concepts since they provide the students with code skeletons to fill without considering any language restriction. Teaching basic and advanced programming courses taught us that students tend to confuse the learning of programming with the learning of the programming language. The students try to master the programming language by learning any tiny little detail of it; in the hope that such details hide an easy solution to the proposed assignments. Evidently, this approach promotes the wrong belief that to learn programming means to learn the programming language instead of the correct thinking that programming is a matter of being able to solve problems independently of the used programming language. Problem solving is typically taught by examples and this approach seconds the misbelief th- students have about what programming is. The solution to a problem is often presented as an already cooked algorithm written in the programming language of choice. Hardly the teacher has the time during his lesson to present the mind process to get to such a solution, since he is already busy in describing the syntactic constructs used in the program, what they do, and all the possible variants the language proposes. Students that still have to tune up their programming skills are disoriented by this approach: they understand what the program does but they cannot either cook their own solution or adapt the proposed solution to a different context. More pre-cooked solutions they get and more difficult for them becomes to separate the programming language from the problem solving. At the very end, students rarely get acquainted to the full-extent of the programming language they use, and they feel disoriented when facing problems that slightly divert from those presented in the lectures. Even smarter students maintain a solving approach based upon few constructs that they master at the best, which often is not the most effective approach. This is a more evident side-effect when the learner is exposed to the whole language since the beginning and without any constraints on what construct to use in solving a given problem. Training students to problem solving means to let them fully explore what they have at their hands, sometimes addressing them to different solution strategies. But if the tool is too complex, the exploration requires too much time that the students steal from thinking about the problem. Sometimes the only way to get students to experiment something is to force them in that direction by limiting the choice to a particular group of language constructs. Some extreme positions include to delay the coding and thus the learning of the language. In our opinion, this could help the students to focus on problem solving but coding and all the other aspects re"},"correct_answer":{"kind":"string","value":"Learning programming is a difficult task. Such difficulties depends on the chosen programming language and the exposure to the single programming concept. Mainstream programming languages such as Java, C and C++ are the most popular. But their innate complexity and the complexity of their tools risk to divert students' attention from the key point of learning appropriate programming techniques in general. Students that approach learning programming tend to focus on learning the programming language since it looks more practicable. The prominent issue lies within the core components of these languages: each programming language consists of many different features-such as control flow, variable definition, and so on-, each bound to a different group of constructs of the language. Due to their strict intertwining, the students are forced to keep up with a considerable quantity of unknown constructs and concepts since the beginning. This issue aggravates if we consider that many of these constructs are not meant to be fully explained until much further in the course, or worse, never. Also support tools, as IDEs, do not help the teacher in the compartmentalization of the programming concepts since they provide the students with code skeletons to fill without considering any language restriction. Teaching basic and advanced programming courses taught us that students tend to confuse the learning of programming with the learning of the programming language. The students try to master the programming language by learning any tiny little detail of it; in the hope that such details hide an easy solution to the proposed assignments. Evidently, this approach promotes the wrong belief that to learn programming means to learn the programming language instead of the correct thinking that programming is a matter of being able to solve problems independently of the used programming language. Problem solving is typically taught by examples and this approach seconds the misbelief th- students have about what programming is. The solution to a problem is often presented as an already cooked algorithm written in the programming language of choice. Hardly the teacher has the time during his lesson to present the mind process to get to such a solution, since he is already busy in describing the syntactic constructs used in the program, what they do, and all the possible variants the language proposes. Students that still have to tune up their programming skills are disoriented by this approach: they understand what the program does but they cannot either cook their own solution or adapt the proposed solution to a different context. More pre-cooked solutions they get and more difficult for them becomes to separate the programming language from the problem solving. At the very end, students rarely get acquainted to the full-extent of the programming language they use, and they feel disoriented when facing problems that slightly divert from those presented in the lectures. Even smarter students maintain a solving approach based upon few constructs that they master at the best, which often is not the most effective approach. This is a more evident side-effect when the learner is exposed to the whole language since the beginning and without any constraints on what construct to use in solving a given problem. Training students to problem solving means to let them fully explore what they have at their hands, sometimes addressing them to different solution strategies. But if the tool is too complex, the exploration requires too much time that the students steal from thinking about the problem. Sometimes the only way to get students to experiment something is to force them in that direction by limiting the choice to a particular group of language constructs. Some extreme positions include to delay the coding and thus the learning of the language. In our opinion, this could help the students to focus on problem solving but coding and all the other aspects re"},"documents":{"kind":"list like","value":["Title: Freely Annotating C#\nYear: 2005\n\nAbstract: Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The annotation model, both in Java and in C#, limits annotations to classes and class members. In this paper we describe [a] C#(a), an extension of the C# programming language, that allows programmers to annotate statements and code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. We also discuss how to use [a] C# to annotate programs giving hints on how to parallelize a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language. Finally, we show how our model for custom attributes has been realized.","Title: Reflective Authorization Systems\nYear: 1998\n\nAbstract: A reflective approach for modeling and implementing autho- rization systems is presented. The advantages of the combined use of computational reflection and authorization mechanis ms are discussed, and three reflective architectures are exami ned for pointing out the corresponding merits and defects. Keywords: Authorization, Object-Orientation, Dis- tributed Objects, Reflection, Security.","Title: 9th international workshop on aspect-oriented modeling\nYear: 2006\n\nAbstract: This report summarizes the outcomes of the 9th Workshop on Aspect-Oriented Modeling (AOM) held in conjunction with the 9th International Conference on Model Driven Engineering Languages and Systems - MoDELS 2006 - in Genoa, Italy, on the 1st of October 2006. The workshop brought together approximately 25 researchers and practitioners from two communities: aspect-oriented software development and software model engineering. It provided a forum for discussing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, software architecture, detailed design, and mapping to aspect-oriented programming constructs. This paper gives an overview of the accepted submissions and summarizes the results of the different discussion groups. Papers and presentation slides of the workshop are available at http://www.aspect-modeling.org/.","Title: @Java: annotations in freedom\nYear: 2013\n\nAbstract: The ability to annotate code and, in general, the capability to attach arbitrary metadata to portions of a program are features that have become more and more common in programming languages. In fact, various programming techniques and tools exploit their explicit availability for a number of purposes, such as extracting documentation, guiding code profiling, enhancing the description of a data type, marking code for instrumentation (for instance, in aspect-oriented frameworks), and the list could go on. While support to attach metadata to code is not a new concept (programming platforms as CLOS and Smalltalk have pioneered in this field), consistent, pervasive APIs to define and manage code annotations are something comparatively recent on modern platforms like the .NET and Java. Annotations in Java make possible to attach custom, structured metadata to declarations of classes, fields and methods. With this work, we propose an extension to Java (named @Java) that has a richer annotation model, supporting code block and expression annotations. In other words, the granularity of annotations extends to the statement and expression level and does not limit to class, method and field declarations.","Title: Static header as sentinel\nYear: 1998\n\nAbstract: Writing code to handle dynamic data structures might seem to be an easy task, but write an efficient, readable and maintainable code is not such a simple task.In this short note we investigate some problems in developing code for handling dynamic data structures, and we propose techniques to overcome them. We take into account the interesting method proposed by Qiu in SIGPLAN Notices [3].Many authors have addressed the problem of handling dynamic data structures by suggesting several clever tricks to simplify dynamic data structures management [4, 2] and to avoid the non-uniform behavior of empty data structures, and access to the first and the last element. In particular, the use of data sentinels and dummy headers makes the implementation more orthogonal and easy to maintain. The cost is a slightly increased size in space which is negligible when compared with the benefits produced.","Title: Sectional domain specific languages\nYear: 2009\n\nAbstract: Nowadays, many problems are solved by using a domain specific language (DSL), i.e., a programming language tailored to work on a particular application domain. Normally, a new DSL is designed and implemented from scratch requiring a long time-to-market due to implementation and testing issues. Whereas when the DSL simply extends another language it is realized as a source-to-source transformation or as an external library with limited flexibility. The Hive framework is developed with the intent of overcoming these issues by providing a mechanism to compose different programming features together forming a new DSL, what we call a sectional DSL. The support (both at compiler and interpreter level) of each feature is separately described and easily composed with the others. This approach is quite flexible and permits to build up a new DSL from scratch or simplifying an existing language without penalties. Moreover, it has the desirable side-effect that each DSL can be extended at any time potentially also at run-time.","Title: Self-Evolving Petri Nets\nYear: 2007\n\nAbstract: Nowadays, software evolution is a very hot topic. It is particularly complex when it regards critical and nonstopping systems. Usually, these situations are tackled by hard- coding all the foreseeable evolutions in the application design and code. Neglecting the obvious difficulties in pursuing this approach, we also get the application code and design polluted with details that do not regard the current system functionality, and that hamper design analysis, code reuse and application maintenance in general. Petri Nets ( PN), as a formalism for modeling and designing distributed/concurrent software systems, are not exempt from this issue. The goal of this work is to propose a PN based reflective framework that lets everyone model a system able to evolve, keeping separated functional aspects from evolutionary ones and applying evolution to the model only if necessary. Such an approach tries to keep system's model as simple as possible, preserving ( and exploiting) ability of formally verifying system properties typical of PN, granting at the same time adaptability.","Title: Neverlang 2: a framework for modular language implementation\nYear: 2014\n\nAbstract: Neverlang 2 is a JVM-based framework for language development that emphasizes code reuse through composition of language features. This paper is aimed at showing how to develop extensible, custom languages using Neverlang's component-based model of implementation. Using this model, each feature of the language can be implemented as a separate, conceptually isolated unit that can be compiled and distributed separately from the others. A live tutorial of the framework can be found at http://youtu.be/Szxvg7XLbXc","Title: Report of the 14th International Workshop on Aspect-Oriented Modeling\nYear: 2010\n\nAbstract: This report summarizes the outcome of the 14th Workshop on Aspect-Oriented Modeling (AOM), as part of the 12th International Conference on Model Driven Engineering Languages and Systems MoD-ELS 2009 in Denver, Colorado, USA, on the 4th of October 2009. The workshop brought together researchers and practitioners from two communities: aspect-oriented software development (AOSD) and software model engineering. This paper gives an overview of the accepted submissions, and summarizes the results of the discussion.","Title: @Java: Bringing a richer annotation model to Java.\nYear: 2014\n\nAbstract: The ability to annotate code and, in general, the capability to attach arbitrary meta-data to portions of a program are features that have become more and more common in programming languages.","Title: Guest editors' introduction: aspects and software evolution\nYear: 2007\n\nAbstract: Software evolution and adaptation is a research area, as also the name states, in continuous evolution, that offers stimulating\n challenges for both academic and industrial researchers. The evolution of software systems, to face unexpected situations\n or just for improving their features, relies on software engineering techniques and methodologies, that often imply re-designing,\n refactoring and re-coding part of or the whole system. Nowadays, similar approaches are not applicable in all situations (e.g.,\n for evolving non-stopping systems or systems whose code is not available) and different approaches are necessary.","Title: SmartMethod: an efficient replacement for method\nYear: 2004\n\nAbstract: In the last few years the interest in reflection has grown and many modern programming languages/architectures have provided the programmer with reflective mechanisms. As well as any other novelty also reflection has detractors. They rightly or wrongly accuse reflection to be too inefficient to be used with real profit. In this work, we have investigated about the performance of Java reflection library (especially of the class Method and of its method invoke) and realized a mechanism which improves its performances. Our mechanism consists of a class, named SmartMethod and of a parser contributing to transform reflective invocations into direct call carried out by the standard invocation mechanism of Java. The SmartMethod class is compliant --- that is, it provides exactly the same services ---, with the class Method of the standard Java core reflection library but it provides a more efficient reflective method invocation.","Title: Getting Farther on Software Evolution via AOP and Reflection\nYear: 2008\n\nAbstract: Following last four years' RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop at the ECOOP conference, the RAM-SE'08 workshop was a successful and popular event. As its name implies, the workshop's focus was on the application of reflective, aspect-oriented and data-mining techniques to the broad field of software evolution. Topics and discussions at the workshop included mechanisms for supporting software evolution, technological limits of the aspect-oriented and reflective approaches to software evolution and tools devoted to software evolution. The workshop's main goal was to bring together researchers working in the field of software evolution with a particular interest in reflection, aspect-oriented programming and meta-data. The workshop was organized as a full day meeting, partly devoted to presentation of submitted position papers and partly devoted to panel discussions about the presented topics and other interesting issues in the field. In this way, the workshop allowed participants to get acquainted with each other's work, and stimulated collaboration. We hope this helped participants in improving their ideas and the quality of their future publications. The workshop's proceedings, including all accepted position papers can be downloaded from the workshop's web site and a post workshop proceeding, including an extension of the accepted paper is planned to be published by the University of Magdeburg. In this report, we provide a session-by-session overview of the workshop, and then present our opinions about future trends in software evolution.","Title: Evolving Pointcut Definition to Get Software Evolution\nYear: 2004\n\nAbstract: In this paper, we have briefly analyzed the aspect-oriented approach with respect to the software evolution topic. The aim of this analysis is to high- light the aspect-oriented potentiality for software evolution and its limits. From our analysis, we can state that actual pointcut definition mechanisms are not enough expressive to pick out from design information where software evolu- tion should be applied. We will also give some suggestions about how to improve the pointcut definition mechanism.","Title: Evaluation of Object-Oriented Reflective Models\nYear: 1998\n\nAbstract: In this paper we explore the object-oriented reflective world, performing an overview of the existing models and presenting a set of features suitable to evaluate the quality of each reflective model. The purpose of the pa- per is to determine the context applicability of each re- flective model examined.","Title: Recognizing join points from their context through graph grammars\nYear: 2009\n\nAbstract: Aspect-oriented software development has been proposed with the intent of better modularizing object-oriented programs by confining crosscutting concerns in aspects. Unfortunately, the aspects do not completely keep their promises. Most of the current approaches revealed to be tightly coupled with the base-program's code compromising the modularity. Moreover, the feasible modularization has a coarse-grain since the aspects can only be woven at the public interface level but not on a generic statement. We have designed the Blueprint framework to overcome these limits. The join points are located through the description of the context where they could be found. This work is about the framework realization and the role that graph grammars play in locating the join points in the base-program from the context description.","Title: A Reflective PN-Based Approach to Dynamic Workflow Change\nYear: 2007\n\nAbstract: The design of dynamic workflows needs adequate modeling/specification formalisms and tools to soundly handle possible changes occurring during workflow operation. A common approach is to pollute design with details that do not regard the current workflow behavior, but rather its evolution. That hampers analysis, reuse and maintenance in general. We propose and discuss the adoption of a recent Petri Net based reflective model (based on classical PN) as a support to dynamic workflow design, by addressing a localized problem: how to determine what tasks should be redone and which ones do not when transferring a workflow instance from an old to a new template. Behind there is the idea that keeping functional aspects separated from evolutionary ones, and applying evolution to the (current) workflow template only when necessary, results in a simple reference model on which the ability of formally verifying typical workflow properties is preserved, thus favoring a dependable adaptability. Keywords: Dynamic Workflow, Petri Nets, Reflection, Evolution.","Title: Smart Data Caching in Archeological Wireless Applications: the PAST Solution\nYear: 2003\n\nAbstract: Wireless computing, because of the limited memory capacity of the palmtops, forces to separate data (stored on a remote server) from the application (running on the palmtops) that uses them. In applications working on data that frequently change, several kilobytes of data are exchanged between the server and the client palmtops. It is fairly evident that a similar tight coupling may easily saturate the network bandwidth when many palmtops are used in parallel, thus degrading the performances of the application running on it. This paper shows a way to reduce the waste of bandwidth by exploiting at the best the palmtop memory to deal with data caching. The proposed smart data caching is based on context information. We have also applied our method and analyzed its features in a specific application: electronic guide to archeological sites in the PAST EC IT project.","Title: Reflective authorization systems: possibilities, benefits, and drawbacks\nYear: 1999\n\nAbstract: We analyze how to use the reflective approach to integrate an authorization system into a distributed object-oriented framework. The expected benefits from the reflective approach are: more stability of the security layer (i.e., with a more limited number of hidden bugs), better software and development modularity, more reusability, and the possibility to adapt the security module with at most a few changes to other applications. Our analysis is supported by simple and illustrative examples written in Java.","Title: The Role of Design Information in Software Evolution\nYear: 2005\n\nAbstract: Software modeling has received a lot a of attention in the last decade and now is an important support for the design process. Actually, the design process is very important to the usability and understandability of the system, for example functional requirements present a complete description of how the system will function from the user's perspec- tive, while non-functional requirements dictate properties and impose constraints on the project or system. The design models and implementation code must be strictly connected, i.e. we must have correlation and con- sistency between the two views, and this correlation must exist during all the software cycle. Often, the early stages of development, the specifications and the design of the system, are ignored once the code has been devel- oped. This practice cause a lot of problems, in particular when the system must evolve. Nowadays, to maintain a software is a difficult task, since there is a high coupling degree between the software itself and its environment. Often, changes in the environment cause changes in the software, in other words, the system must evolve itself to follow the evolution of its environment. Typically, a design is created initially, but as the code gets written and modified, the design is not updated to reflect such changes. This paper describes and discusses how the design information can be used to drive the software evolution and consequently to maintain consistence among design and code.","Title: RAMSES: a Reflective Middleware for Software Evolution\nYear: 2004\n\nAbstract: Software systems today need to dynamically self-adapt against dynamic requirement changes. In this paper we describe RAMSES a reflective middleware whose aim consists of consistently evolving software systems against runtime changes. This middleware provides the ability to change both structure and behavior for the base-level system at run-time by using its design information. The meta-level is composed of cooper- ating objects, and has been specified by using a design pattern language. The base objects are controlled by meta-objects that drive their evolution. The essence of RAMSES is the ability of extracting the design data from the base application, and of constraining the dynamic evolution to stable and consistent systems.","Title: Shifting Up Reflection from the Implementation to the Analysis Level\nYear: 1999\n\nAbstract: Traditional methods for object-oriented analysis and modeling focus on the functional specification of software systems, i.e., application domain modeling. Non-functional requirements such as fault-tolerance, distribution, integration with legacy systems, and so on, have no clear collocation within the analysis process, since they are related to the architecture and workings of the system itself rather than the application domain. They are thus addressed in the system's design, based on the partitioning of the system's functionality into classes resulting from analysis. As a consequence, the smooth transition from analysis to design that is usually celebrated as one of the main advantages of the object-oriented paradigm does not actually hold for what concerns non-functional issues. A side effect is that functional and nonfunctional concerns tend to be mixed at the implementation level. We argue that the reflective approach whereby non-functional properties are ascribed to a meta-level of the software system may be extended \"back to\" analysis. Adopting a reflective approach in object-oriented analysis may support the precise specification of non-functional requirements in analysis and, if used in conjunction with a reflective approach to design, recover the smooth transition from analysis to design in the case of nonfunctional system's properties.","Title: Implementing the essence of reflection: a reflective run-time environment\nYear: 2004\n\nAbstract: Computational reflection provides the developers with a programming mechanism devoted to favorite code extensibility, reuse and maintenance. Notwithstanding that, it has not achieved developers' unanimous acceptance and its full potential yet. In our opinion, this depends on the intrinsic complexity of most of the reflective approaches that hinders their efficient implementation. The aim of this paper consists of defining the essence of reflection, that is, to identify the minimal set of characteristics that a software system must have to be considered reflective. The consequence is the realization of a run-time environment supporting the essence of reflection without affecting the programming language and with a minimal impact on the programming system design. This achievement will improve reflective system performances reducing the impact of one of the most diffuse criticism about reflection: low performance.","Title: Towards a colored reflective Petri-net approach to model self-evolving service-oriented architectures\nYear: 2012\n\nAbstract: Service-based software systems could require to evolve during their execution. To support this, we need to consider system evolving since the design phase. Reflective Petri nets separate the system from its evolution by describing it and how it can evolve. However, reflective Petri nets have some expressivity limits and render overcomplicated the consistency checking necessary during service evolution. In this paper, we extend the reflective Petri nets approach to overcome such limits and show that on a case study.","Title: Context traits: dynamic behaviour adaptation through run-time trait recomposition\nYear: 2013\n\nAbstract: Context-oriented programming emerged as a new paradigm to support fine-grained dynamic adaptation of software behaviour according to the context of execution. Though existing context-oriented approaches permit the adaptation of individual methods, in practice behavioural adaptations to specific contexts often require the modification of groups of interrelated methods. Furthermore, existing approaches impose a composition semantics that cannot be adjusted on a domain-specific basis. The mechanism of traits seems to provide a more appropriate level of granularity for defining adaptations, and brings along a flexible composition mechanism that can be exploited in a dynamic setting. This paper explores how to achieve context-oriented programming by using traits as units of adaptation, and trait composition as a mechanism to introduce behavioural adaptations at run time. First-class contexts reify relevant aspects of the environment in which the application executes, and they directly influence the trait composition of the objects that make up the application. To resolve conflicts arising from dynamic composition of behavioural adaptations, programmers can explicitly encode composition policies. With all this, the notion of context traits offers a promising approach to implementing dynamically adaptable systems. To validate the context traits model we implemented a JavaScript library and conducted case studies on context-driven adaptability.","Title: On The Footprints Of Join Points: The Blueprint Approach\nYear: 2007\n\nAbstract: Aspect-oriented techniques are widely used to better modularize object-oriented programs by introducing crosscutting concerns in a safe and non-invasive way, i.e., aspect-oriented mechanisms better address the modularization of functionality that orthogonally crosscuts the implementation of the application.Unfortunately, as noted by several researchers, most of the current aspect-oriented approaches are too coupled with the application code, and this fact hinders the concerns separability and consequently their re-usability since each aspect is strictly tailored on the base application. Moreover, the join points (i.e., locations affected by a crosscutting concerns) actually are defined at the operation level. It implies that the possible set of join points includes every operation (e.g., method invocations) that the system performs. Whereas, in many contexts we wish to define aspects that are expected to work at the statement level, i.e., by considering as a join point every point between two generic statements (i.e., lines of code).In this paper, we present our approach, called Blueprint, to overcome the above-mentioned limitations of the current aspect-oriented approaches. The Blueprint consists of a new aspect-oriented programming language based on modeling the join point selection mechanism at a high-level of abstraction to decouple aspects from the application code. To this regard, we adopt a high-level pattern-based join point model, where join points are described by join point blueprints, i.e., behavioral patterns describing where the join points should be found.","Title: Architectural Reflection: Realising Software Architectures via Reflective Activities\nYear: 2000\n\nAbstract: Architectural reflection is the computation performed by a software system about its own software architecture. Building on previous research and on practical experience in industrial projects, in this paper we expand the approach and show a practical (albeit very simple) example ofa pplication of architectural reflection. The example shows how one can express, thanks to reflection, both functional and nonfunctional requirements in terms ofob ject-oriented concepts, and how a clean separation ofcon cerns between application domain level and architectural level activities can be enforced.","Title: Rule-Based Strategic Reflection: Observing and Modifying Behavior at the Architectural Level\nYear: 1999\n\nAbstract: As software systems become larger and more complex, a relevant part of code shifts from the application domain to the management of the system's run-time architecture (e.g., substituting components and connectors for run-time automated tuning). We propose a novel design approach for component-based systems supporting architectural management in a systematic and conceptually clean way and allowing for the transparent addition of architectural management functionality to existing systems. The approach builds on the concept of reflection, extending it to the programming-in-the-large level, thus yielding architectural reflection (AR). This paper focuses on one aspect of AR, namely the monitoring and dynamic modification of the system's overall control structure (strategic reflection), which allows the behaviour of a system to be monitored and adjusted without modifying the system itself.","Title: Aspect-oriented procedural content engineering for game design\nYear: 2009\n\nAbstract: Generally progressive procedural content in the context of 3D scene rendering is expressed as recursive functions where a finer level of detail gets computed on demand. Typical examples of content procedurally generated are fractal images and noise textures. Unfortunately, not always the content can be expressed in this way, developers and content creators need the data to have some peculiarity (like windows on a wall for a house 3D model) and a method to drive data simplification without losing relevant details. In this paper we discuss how aspect oriented (AO) techniques can be used to drive the content creation process by mapping each data peculiarity to the code to generate it. Using aspects will let us to partially evaluate the code of the procedure improving the performance without losing the flow of the generation logic. We will also discuss how the use of AO can provide techniques to build simplified version of the data through code transformations.","Title: AOP for software evolution: a design oriented approach\nYear: 2005\n\nAbstract: In this paper, we have briefly explored the aspect-oriented approach as a tool for supporting the software evolution. The aim of this analysis is to highlight the potentiality and the limits of the aspect-oriented development for software evolution. From our analysis follows that in general (and in particular for AspectJ) the approach to join points, pointcuts and advices definition are not enough intuitive, abstract and expressive to support all the requirements for carrying out the software evolution. We have also examined how a mechanism for specifying pointcuts and advices based on design information, in particular on the use of UML diagrams, can better support the software evolution through aspect oriented programming. Our analysis and proposal are presented through an example.","Title: 11th International Workshop on Aspect-Oriented Modeling\nYear: 2007\n\nAbstract: This report summarizes the results and discussions from the 11th Workshop on Aspect-Oriented Modeling (AOM). The workshop was held in conjunction with the International Conference on Model-Driven Engineering, Languages, and Systems (MODELS), which was located in Nashville, Tennes-see, on September 30, 2007. Over 20 researchers and practitioners attended the workshop with various backgrounds in aspect-oriented software development and software model engineering. The workshop provided a forum for discuss-ing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, soft-ware architecture, detailed design, and mapping to aspect-oriented programm-ing constructs. This workshop summary provides an overview of the accepted submissions and summarizes the results of the different discussion groups. Papers, presentation slides, and photos from the workshop are available at http://www.aspect-modeling.org/.","Title: Fine-Grained Software Evolution Using UML Activity and Class Models.\nYear: 2013\n\nAbstract: Modern software systems that play critical roles in society's infrastructures are often required to change at runtime so that they can continuously provide essential services in the dynamic environments they operate in. Updating open, distributed software systems at runtime is very challenging. Using runtime models as an interface for updating software at runtime can help developers manage the complexity of updating software while it is executing. In this work we describe an approach to updating Java software at runtime through the use of runtime models consisting of UML class and activity diagrams. Changes to models are turned into changes on Java source code, which is then propagated to the runtime system using the JavAdaptor technology. In particular, the presented approach permits in-the-small software changes, i.e., changes at the code statement level, as opposed to in-the-large changes, i.e., changes at the component level. We present a case study that demonstrates the major aspects of the approach and its use.","Title: Remote method invocation as a first-class citizen\nYear: 2003\n\nAbstract: The classical remote method invocation (RMI) mechanism adopted by several object-based middleware is 'black-box' in nature, and the RMI functionality, i.e., the RMI interaction policy and its configuration, is hard-coded into the application. This RMI nature hinders software development and reuse, forcing the programmer to focus on communication details often marginal to the application being developed. Extending the RMI behavior with extra functionality is also a very difficult job, because added code must be scattered among the entities involved in communications.This situation could be improved by developing the system in several separate layers, confining communications and related matters to specific layers. As demonstrated by recent work on reflective middleware, reflection represents a powerful tool for realizing such a separation and therefore overcoming the problems referred to above. Such an approach improves the separation of concerns between the communication-related algorithms and the functional aspects of an application. However, communications and all related concerns are not managed as a single unit that is separate from the rest of the application, which makes their reuse, extension, and management difficult. As a consequence, communications concerns continue to be scattered across the meta-program, communication mechanisms continue to be black-box in nature, and there is only limited opportunity to adjust communication policies through configuration interfaces.In this paper we examine the issues raised above, and propose a reflective approach specially designed to open up the Java RMI mechanism. Our proposal consists of a new reflective model, called multi-channel reification, that reflects on and reifies communication channels, i.e., it renders communication channels first-class citizens. This model is designed both for developing new communication mechanisms and for extending the behavior of communication mechanisms provided by the underlying system. Our approach is embodied in a framework called mChaRM, which is described in detail in this paper.","Title: Reflective Analysis and Design for Adapting Object Run-Time Behavior\nYear: 2002\n\nAbstract: Today, complex information systems need a simple way for changing the object behavior according with changes that occur in its running environment. We present a reflective architecture which provides the abilityt o change object behavior at run-time by using design-time information. By integrating reflection with design patterns we get a flexible and easilyad aptable architecture. A reflective approach that describes object model, scenarios and statecharts helps to dynamically adapt the software system to environmental changes. The object model, system scenario and manyot her design information are reified by spe cial meta-objects, named evolutionary meta-objects. Evolutionary meta-objects deal with two types of run-time evolution. Structural evolution is carried out bycau sal connection between evolutionary meta-objects and its referents through changing the structure of these referents by adding or removing objects or relations. Behavioral evolution allows the system to dynamically adapt its behavior to environment changes by itself. Evolutionarym eta-objects react to environment changes for adapting the information theyh ave reified and steering the system evolution. They provide a natural liaison between design information and the system based on such information. This paper describes how this liaison can be built and how it can be used for adapting a running system to environment changes.","Title: A Petri-Net Based Reflective Framework for the Evolution of Dynamic Systems\nYear: 2006\n\nAbstract: Nowadays, software evolution is a very hot topic. Many applications need to be updated or extended with new characteristics during their lifecycle. Software evolution is characterized by its huge cost and slow speed of implementation. Often, software evolution implies a redesign of the whole system, the development of new features and their integration in the existing and/or running systems (this last step often implies a complete rebuilding of the system). A good evolution is carried out through the evolution of the system design information and then propagating the evolution to the implementation. Petri Nets (PN), as a formalism for modeling and designing distributed/concurrent software systems, are not exempt from this issue. Several times a system modeled through Petri nets has to be updated and consequently also the model should be updated. Often, some kinds of evolution are foreseeable and could be hardcoded in the code or in the model, respectively. Embedding evolutionary steps in the model or in the code however requires early and full knowledge of the evolution. The model itself should be augmented with details that do not regard the current system functionality, and that jeopardize or make very hard analysis and verification of system properties. In this work, we propose a PN based reflective framework that lets everyone model a system able to evolve, keeping separated functional aspects from evolutionary ones and applying evolution to the model if necessary. Such an approach tries to keep the model as simple as possible, preserving (and exploiting) the ability of formally verifying system properties typical of PN, granting at the same time model adaptability.","Title: Fine-grained annotations for pointcuts with a finer granularity\nYear: 2013\n\nAbstract: A number of authors have suggested that AspectJ-like pointcut languages are too limited, and that they cannot select every possible join point in a program. Many enhanced pointcut languages have been proposed; they require virtually no change to the original code, but their improved expressive power comes often at the cost of making the pointcut expression too tightly connected with the structure of the programs that are being advised. Other solutions consist in simple extensions to the base language; they require only small changes to the original code, but they frequently serve no other immediate purpose than exposing pieces of code to the weaver. Annotations are a form of metadata that has been introduced in Java 5. Annotations have a number of uses: they may provide hints to the compiler, information to code processing tools and they can be retained at runtime. At the moment of writing, runtime-accessible annotations in the Java programming language can only be applied to classes, fields and methods. The support to annotate expressions and blocks feels like a natural extension to Java's annotation model, that can be also exploited to expose join points at a finer-grained level. In this paper we present an extension to the AspectJ language to select block and expression annotations in the @Java language extension.","Title: Design-Based Pointcuts Robustness Against Software Evolution\nYear: 2006\n\nAbstract: Aspect-Oriented Programming (AOP) is a powerful technique to better modularize object-oriented programs by introducing crosscutting concerns in a safe and noninvasive way. Unfortunately, most of the current join point models are too coupled with the application code. This fact harms the evolvability of the program, hinders the concerns selection and reduces the aspect reusability. To overcome this problem is an hot topic. This work propose a possible solution to the limits of the current aspect-oriented techniques based on model- ing the join point selection mechanism at a higher level of abstraction to decoupling base program and aspects. In this paper, we will present by examples a novel join point model based on design information (e.g., ex- pressed through UML diagrams). Design information provides an high-level view on the application structure and behavior decoupled by base program. A design oriented join point model will render aspect definition more robust against base program evolution, reusable and independent of the base program.","Title: Join point patterns: a high-level join point selection mechanism\nYear: 2006\n\nAbstract: Aspect-Oriented Programming is a powerful technique to better modularize object-oriented programs by introducing crosscutting concerns in a safe and noninvasive way. Unfortunately, most of the current join point models are too coupled with the application code. This fact hinders the concerns separability and reusability since each aspect is strictly tailored on the base application. This work proposes a possible solution to this problem based on modeling the join points selection mechanism at a higher level of abstraction. In our view, the aspect designer does not need to know the inner details of the application such as a specific implementation or the used name conventions rather he exclusively needs to know the application behavior to apply his/her aspects. In the paper, we present a novel join point model with a join point selection mechanism based on a high-level program representation. This high-level view of the application decouples the aspects definition from the base program structure and syntax. The separation between aspects and base program will render the aspects more reusable and independent of the manipulated application.","Title: AOP-HiddenMetrics: Separation, Extensibility and Adaptability in SW Measurement\nYear: 2008\n\nAbstract: Traditional approaches to dynamic system analysis and metrics measurement are based on system code (both source, intermediate and executable code) instrumentation or need ad hoc support by the run-time environment. In these contexts, the measurement process is tricky, invasive and the results could be affected by the process itself making the data not germane. Moreover, the tool based on these approaches are difficult to customize, extend and often use since their properties are rooted at specific system details (e.g., special tools such as bytecode analyzers or virtual machine goodies such as the debugger interface) and require high efforts, skills and knowledges to be adapted. Notwithstanding its importance, software measurement is clearly a nonfunctional con- cern and should not impact on the software development and efficiency. Aspect- oriented programming provides the mechanisms to deal with this kind of concern and to overcome the software measurement limitations. In this paper, we present a different approach to dynamic software measurements based on aspect-oriented programming and the corresponding support framework named AOPÂHiddenMetrics. The proposed approach makes the measurement process highly customizable and easy to use reducing its invasiveness and the dependency from the code knowledge.","Title: JavAdaptor: unrestricted dynamic software updates for Java\nYear: 2011\n\nAbstract: Dynamic software updates (DSU) are one of the top-most features requested by developers and users. As a result, DSU is already standard in many dynamic programming languages. But, it is not standard in statically typed languages such as Java. Even if at place number three of Oracle's current request for enhancement (RFE) list, DSU support in Java is very limited. Therefore, over the years many different DSU approaches for Java have been proposed. Nevertheless, DSU for Java is still an active field of research, because most of the existing approaches are too restrictive. Some of the approaches have shortcomings either in terms of flexibility or performance, whereas others are platform dependent or dictate the program's architecture. With JavAdaptor, we present the first DSU approach which comes without those restrictions. We will demonstrate JavAdaptor based on the well-known arcade game Snake which we will update stepwise at runtime.","Title: Variability Support in Domain-Specific Language Development.\nYear: 2013\n\nAbstract: Domain Specific Languages (DSLs) are widely adopted to capitalize on business domain experiences. Consequently, DSL development is becoming a recurring activity. Unfortunately, even though it has its benefits, language development is a complex and time-consuming task. Languages are commonly realized from scratch, even when they share some concepts and even though they could share bits of tool support. This cost can be reduced by employing modern modular programming techniques that foster code reuse. However, selecting and composing these modules is often only within the reach of a skilled DSL developer. In this paper we propose to combine modular language development and variability management, with the objective of capitalizing on existing assets. This approach explicitly models the dependencies between language components, thereby allowing a domain expert to configure a desired DSL, and automatically derive its implementation. The approach is tool supported, using Neverlang to implement language components, and the Common Variability Language (CVL) for managing the variability and automating the configuration. We will further illustrate our approach with the help of a case study, where we will implement a family of DSLs to describe state machines.","Title: Visualizing and Managing Network Topologies via Rectangular Dualization\nYear: 2006\n\nAbstract: Rectangular dualization is an effective, hierarchically oriented visualization method for network topologies and can be used in many other problems having in common with networks the condition that objects and their interoccurring relations are represented by means of a planar graph. However, only 4-connected triangulated planar graphs admit a rectangular dual. In this paper we present a linear time algorithm to optimally construct a rectangular layout for a general class of graphs and we discuss a variety of application fields where this approach represents an helpful support for visualization tools.","Title: Software evolution: a trip through reflective, aspect, and meta-data oriented techniques\nYear: 2004\n\nAbstract: Previous workshops related to aspect oriented software development, reflection organized at previous ECOOP conferences (e.g., RMA'00. and AOMMeT'01. ) and conferences on the same topics (Reflection'01 and AOSD since 2002) have pointed out the growing interest on these topics and their relevance in the software evolution as techniques for code instrumentation. Very similar conclusions can be drawn by reading the contributions to the workshops on unanticipated software evolution (USE 2002 and USE 2003. ). Following the example provided by these venues, the RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop has provided an opportunity for researchers with a broad range of interests in reflective techniques and aspect-oriented software development to discuss recent developments of such a techniques in application to the software evolution. The workshop main goal was to encourage people to present works in progress. These works could cover all the spectrum from theory to practice. To ensure creativity, originality, and audience interests, participants have been selected by the workshop organizers on the basis of 5-page position paper. We hope that the workshop will help them to mature their ideas and to improve the quality of their future publications based on the presented work. The workshop proceedings are available as research report C-186 of the Department of Mathematical and Computing Sciences of the Tokyo Institute of Technology and freely downlodable from the workshop web site.","Title: SmartReflection: Efficient Introspection in Java\nYear: 2004\n\nAbstract: In the last few years the interest in reflection has grown and many modern programming languages/environments (e.g., Java and .NET) have provided the programmer with reflective mechanisms, i.e., with the ability of dynamically looking into (introspect) the structure of the code from the code itself. In spite of its evident usefulness, reflection has many detractors, who claim that it is too inecient to be used with real profit. In this work, we have investigated about the performance issue in the context of the Java reflection library and presented a dierent approach to the introspection in Java that improves its performances. The basic idea of the proposed approach consists of moving most of the overhead due to the dynamic introspection from run-time to compile- time. The eciency improvement has been proved by providing a new reflection library compliant - that is, it provides exactly the same services -, with the standard Java reflection library based on the proposed approach. This paper is focused on speeding up the reification and the invocation of methods, i.e., on the class SmartMethod that replaces the class Method of the standard reflection library.","Title: Seamless Nomadic System-Aware Servants\nYear: 2004\n\nAbstract: The growing diffusion of wireless technologies is leading to deployment of small-scale and location dependent information services (LDISs). Those new services call for provisioning schemes that are able to operate in a distributed environment and do not require networkinfrastructure. This paper describes an approach to a service-oriented middleware which enables a mobile device to be aware of the surrounding environment and to transparently exploit every LDIS discovered in the coverage area of the hosting wireless network. the paperintroduces seamless nomadic system-aware (SNA) servant. SNA servants run on mobile devices, discover LDISs and are not associated with any specific service. The paper also describes the key features for the SNA servants implementation and for rendering them interoperable and cross-platform on, at least, .NET and JVM frameworks.","Title: Towards a model-driven join point model\nYear: 2006\n\nAbstract: Aspect-Oriented Programming (AOP) is increasingly being adopted by developers to better modularize object-oriented design by introducing crosscutting concerns. However, due to tight coupling of existing approaches with the implementing code and to the poor expressiveness of the pointcut languages a number of problems became evident. We believe that such problems could be solved shifting the focus of software development from a programming language specific implementation to application design. This work presents a possible solution based on modeling aspects at a higher level of abstraction which are, in turn, transformed to specific targets.","Title: Evolving System's Modeling and Simulation through Reflective Petri Nets\nYear: 2009\n\nAbstract: The design of dynamic discrete-event systems calls for adequate modeling formalisms and tools to manage possible changes occurring during system's lifecycle. A common approach is to pollute design with details that do not regard the current system behavior rather its evolution. That hampers analysis, reuse and maintenance in general. A reflective Petri net model (based on classical Petri nets) was recently proposed to support dynamic discrete-event system's design, and was applied to dynamic workflow's management. Behind there is the idea that keeping functional aspects separated from evolutionary ones and applying them to the (current) system only when necessary, results in a simple formal model on which the ability of verifying properties typical of Petri nets is preserved. In this paper we provide the reflective Petri nets with a (labeled) state-transition graph semantics.","Title: (Symbolic) state-space inspection of a class of dynamic Petri nets\nYear: 2010\n\nAbstract: The design of dynamic or adaptable discrete-event systems needs for adequate modeling techniques in order to manage possible structural changes occurring during system's lifecycle. An usual approach is that of polluting design with details not concerning the (current) system behavior, rather its evolution. That hampers analysis, reuse and maintenance in general. A Petri net-based reflective layout based on classical Petri nets was recently proposed to support dynamic discrete-event system's design, and was applied to dynamic workflows. The basic idea is that keeping functional aspects separated from evolutionary ones, deploying evolution on the (current) system configuration when necessary, results in a clean formal model for dynamic systems. This model preserves the ability of verifying properties typical of classical Petri nets. As a first step toward the implementation of a discrete-event simulator, Reflective Petri nets are provided with a (symbolic) reduced state-transition graph.","Title: JavAdaptor-Flexible runtime updates of Java applications\nYear: 2013\n\nAbstract: AbstractSoftware is changed frequently during its life cycle. New requirements come, and bugs must be fixed. To update an application, it usually must be stopped, patched, and restarted. This causes time periods of unavailability, which is always a problem for highly available applications. Even for the development of complex applications, restarts to test new program parts can be time consuming and annoying. Thus, we aim at dynamic software updates to update programs at runtime. There is a large body of research on dynamic software updates, but so far, existing approaches have shortcomings either in terms of flexibility or performance. In addition, some of them depend on specific runtime environments and dictate the program's architecture. We present JavAdaptor, the first runtime update approach based on Java that a offers flexible dynamic software updates, b is platform independent, c introduces only minimal performance overhead, and d does not dictate the program architecture. JavAdaptor combines schema changing class replacements by class renaming and caller updates with Java HotSwap using containers and proxies. It runs on top of all major standard Java virtual machines. We evaluate our approach's applicability and performance in non-trivial case studies and compare it with existing dynamic software update approaches. Copyright © 2012 John Wiley & Sons, Ltd.","Title: AOP vs Software Evolution: a Score in Favor of the Blueprint\nYear: 2007\n\nAbstract: All software systems are subject to evolution, independently by the developing technique. Aspect oriented software in addition to sep- arate the different concerns during the software development, must be \"not fragile\" against software evolution. Otherwise, the benefit of disentangling the code will be burred by the extra complication in maintaining the code. Toobtainthisgoal, theaspect-orientedlanguages/toolsmustevolve, they have to be less coupled to the base program. In the last years, a few attempts have been proposed, the Blueprint is our proposal based on behavioral patterns. InthispaperwetesttherobustnessoftheBlueprintaspect-oriented language against software evolution.","Title: [a]C#: C# with a customizable code annotation mechanism\nYear: 2005\n\nAbstract: Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The extensible model proposed in both platforms limits annotations to class members. In this paper we describe [a]C#,1 an extension of the C# programming language, that allows programmers to annotate statements or code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. Finally, we discuss how to use [a]C# to annotate programs giving hints on how to parallel a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language.","Title: Reflection and Meta-level Architectures: State of the Art and Future Trends\nYear: 2000\n\nAbstract: Previous workshops on reflection both in ECOOP and in OOPSLA have pointed out the growing interest and importance of Reflection and Metalevel Architectures in the fields of programming languages and systems (ECOOP'98, OOPSLA'98), software engineering (OOPSLA'99) and middleware (Middleware 2000). Following these workshops but also the conference Reflection'99 held in Saint-Malo (France), this workshop has provided an opportunity for researchers with a broad range of interests in meta-level architectures and reflective techniques to discuss recent developments in this field. It has also provided a good test-bed for preparing them to submit their works to Reflection'01. The workshop main goal is to encourage people to present works in progress. These works could cover all the spectrum from theory to practice. To ensure creativity, originality, and audience interests, participants have been selected by the workshop organizers on the basis of 5-page position paper. We hope that the workshop will help them to mature their idea and improve the quality of their future publications based on the presented work.","Title: Domain-Specific languages in few steps: the neverlang approach\nYear: 2012\n\nAbstract: Often an ad hoc programming language integrating features from different programming languages and paradigms represents the best choice to express a concise and clean solution to a problem. But, developing a programming language is not an easy task and this often discourages from developing your problem-oriented or domain-specific language. To foster DSL development and to favor clean and concise problem-oriented solutions we developed Neverlang The Neverlang framework provides a mechanism to build custom programming languages up from features coming from different languages. The composability and flexibility provided by Neverlang permit to develop a new programming language by simply composing features from previously developed languages and reusing the corresponding support code (parsers, code generators, …). In this work, we explore the Neverlang framework and try out its benefits in a case study that merges functional programming à la Python with coordination for distributed programming as in Linda.","Title: Co-evolving application code and design models by exploiting meta-data\nYear: 2007\n\nAbstract: Evolvability and adaptability are intrinsic properties of today's software applications. Unfortunately, the urgency of evolving/adapting a system often drives the developer to directly modify the application code neglecting to update its design models. Even, most of the development environments support the code refactoring without supporting the refactoring of the design information. Refactoring, evolution and in general every change to the code should be reflected into the design models, so that these models consistently represent the application and can be used as documentation in the successive maintenance steps. The code evolution should not evolve only the application code but also its design models. Unfortunately, to co-evolve the application code and its design is a hard job to be carried out automatically, since there is an evident and notorious gap between these two representations. We propose a new approach to code evolution (in particular to code refactoring) that supports the automatic co-evolution of the design models. The approach relies on a set of predefined metadata that the developer should use to annotate the application code and to highlight the refactoring performed on the code. Then, these meta-data are retrieved through reflection and used to automatically and coherently update the application design models.","Title: On the Maintainability of Aspect-Oriented Software: A Concern-Oriented Measurement Framework\nYear: 2008\n\nAbstract: Aspect-oriented design needs to be systematically assessed with respect to modularity flaws caused by the realization of driving system concerns, such as tangling, scattering, and excessive concern dependencies. As a result, innovative concern metrics have been defined to support quantitative analyses of concern's properties. However, the vast majority of these measures have not yet being theoretically validated and managed to get accepted in the academic or industrial settings. The core reason for this problem is the fact that they have not been built by using a clearly-defined terminology and criteria. This paper defines a concern-oriented framework that supports the instantiation and comparison of concern measures. The framework subsumes the definition of a core terminology and criteria in order to lay down a rigorous process to foster the definition of meaningful and well-founded concern measures. In order to evaluate the framework generality, we demonstrate the framework instantiation and extension to a number of concern measures suites previously used in empirical studies of aspect-oriented software maintenance.","Title: A concern-oriented framework for dynamic measurements.\nYear: 2015\n\nAbstract: Evolving software programs requires that software developers reason quantitatively about the modularity impact of several concerns, which are often scattered over the system. To this respect, concern-oriented software analysis is rising to a dominant position in software development. Hence, measurement techniques play a fundamental role in assessing the concern modularity of a software system. Unfortunately, existing measurements are still fundamentally module-oriented rather than concern-oriented. Moreover, the few available concern-oriented metrics are defined in a non-systematic and shared way and mainly focus on static properties of a concern, even if many properties can only be accurately quantified at run-time. Hence, novel concern-oriented measurements and, in particular, shared and systematic ways to define them are still welcome. This paper poses the basis for a unified framework for concern-driven measurement. The framework provides a basic terminology and criteria for defining novel concern metrics. To evaluate the framework feasibility and effectiveness, we have shown how it can be used to adapt some classic metrics to quantify concerns and in particular to instantiate new dynamic concern metrics from their static counterparts.","Title: On the incremental growth and shrinkage of LR goto-graphs\nYear: 2014\n\nAbstract: The LR(0) goto-graph is the basis for the construction of parsers for several interesting grammar classes such as LALR and GLR. Early work has shown that even when a grammar is an extension to another, the goto-graph of the first is not necessarily a subgraph of the second. Some authors presented algorithms to grow and shrink these graphs incrementally, but the formal proof of the existence of a particular relation between a given goto-graph and a grown or shrunk counterpart seems to be still missing in literature as of today. In this paper we use the recursive projection of paths of limited length to prove the existence of one such relation, when the sets of productions are in a subset relation. We also use this relation to present two algorithms (Grow and Shrink) that transform the goto-graph of a given grammar into the goto-graph of an extension or a restriction to that grammar. We implemented these algorithms in a dynamically updatable LALR parser generator called DEXTER (the Dynamically EXTEnsible Recognizer) that we are now shipping with our current implementation of the Neverlang framework for programming language development.","Title: Automating variability model inference for component-based language implementations\nYear: 2014\n\nAbstract: Recently, domain-specific language development has become again a topic of interest, as a means to help designing solutions to domain-specific problems. Componentized language frameworks, coupled with variability modeling, have the potential to bring language development to the masses, by simplifying the configuration of a new language from an existing set of reusable components. However, designing variability models for this purpose requires not only a good understanding of these frameworks and the way components interact, but also an adequate familiarity with the problem domain. In this paper we propose an approach to automatically infer a relevant variability model from a collection of already implemented language components, given a structured, but general representation of the domain. We describe techniques to assist users in achieving a better understanding of the relationships between language components, and find out which languages can be derived from them with respect to the given domain.","Title: Using models to dynamically refactor runtime code\nYear: 2014\n\nAbstract: Modern software systems that play critical roles in society's infrastructures are often required to change at runtime so that they can continuously provide essential services in the dynamic environments they operate in. Updating open, distributed software systems at runtime is very challenging. Using runtime models as an interface for updating software at runtime can help developers manage the complexity of updating software while it is executing. To support this idea, we developed the FiGA framework that permits developers to update running software through changes made to UML models of the running software. In this paper, we address the following question: can the UML models be used to express any type of code change a developer desires? Specifically, we report our experience on applying Fowler's code refactoring catalog through model refactoring in the FiGA framework. The goal of this work is to show that the set of FiGA change operators is complete by showing that the refactorings at the source code level can be expressed as model changes in the FiGA approach.","Title: A fresh look at programming-in-the-large\nYear: 1998\n\nAbstract: Realizing a shift of software engineering towards a component-based approach to software development re- quires the development of higher level programming systems supporting the development of systems from components. This paper presents a novel approach to the design of large software systems where a program-in-the- large describing the system's architecture is executed at run-time to rule over the assembly and dynamic coopera- tion of components. This approach has several advan- tages following from a clean separation of concerns be- tween programming-in-the-small and programming-in- the-large issues in instantiated systems. Based on these considerations, we propose a new ap- proach to programming-i n-the-large which is centred around two main ideas: the program-in-the-large of a system should describe the system's architecture; and it should be executed at run-time as an independent (higher- level) program with respect to the components' pro- grams. We term this approach Dynamic Architectural Programming-in-the-Large (DAPIL). This paper presents this vision. Section 2 provides the rationale for DAPIL by stating the implicit architecture problem underlying current approaches to component-based development. In section 3, we present a sample syntax and semantics for a programming language for DAPIL and in section 4 we sketch the component and system model underlying them. Section 5 discusses how our approach accommo- dates addressing dynamic architectures in a reflective way. Section 6 points out at some benefits of the pro- posed approach and section 7 draws some conclusion and presents future work. 2: The implicit architecture problem","Title: Neverlang: A framework for feature-oriented language development\nYear: 2015\n\nAbstract: Reuse in programming language development is an open research problem. Many authors have proposed frameworks for modular language development. These frameworks focus on maximizing code reuse, providing primitives for componentizing language implementations. There is also an open debate on combining feature-orientation with modular language development. Feature-oriented programming is a vision of computer programming in which features can be implemented separately, and then combined to build a variety of software products. However, even though feature-orientation and modular programming are strongly connected, modular language development frameworks are not usually meant primarily for feature-oriented language definition. In this paper we present a model of language development that puts feature implementation at the center, and describe its implementation in the Neverlang framework. The model has been evaluated through several languages implementations: in this paper, a state machine language is used as a means of comparison with other frameworks, and a JavaScript interpreter implementation is used to further illustrate the benefits that our model provides.","Title: Using Models to Validate Unanticipated, Fine-Grained Adaptations at Runtime\nYear: 2016\n\nAbstract: An increasing number of modern software systems need to be adapted at runtime while they are still executing. It becomes crucial to validate each adaptation before it is deployed to the running system. Models are used to ease software maintenance and can, therefore, be used to manage dynamic software adaptations. For example, models are used to manage coarse-grained anticipated adaptations for self-adaptive systems. However, the need for both fine-grained and unanticipated adaptations is becoming increasingly common, and their validation is also becoming more crucial. This paper proposes an approach to validate unanticipated, fine-grained adaptations performed on models before the adaptations are deployed into the running system. The proposed approach exploits model execution where model representations of the test suites of a software system are executed. The proposed approach is demonstrated and evaluated within the Fine Grained Adaptation (FiGA) framework.","Title: DSL evolution through composition\nYear: 2010\n\nAbstract: The use of domain specific languages (DSL), instead of general purpose languages introduces a number of advantages in software development even if could be problematic to maintain the DSL consistent with the evolution of the domain. Traditionally, to develop a compiler/interpreter from scratch but also to modify an existing compiler to support the novel DSL is a long and difficult task. We have developed Neverlang to simplify and speed up the development and maintenance of DSLs. The framework presented in this article not only allows to develop the syntax and the semantic of a new language from scratch but it is particularly focused on the reusability of the language definition. The interpreters/compilers produced with such a framework are modular and it is easy to add remove or modify their sections. This allows to modify the DSL definition in order to follow the evolution of the underneath domain. In this work, we explore the Neverlang framework and try out the adaptability of its language definition.","Title: Engineering sustainability through language\nYear: 2015\n\nAbstract: As our understanding and care for sustainability concerns increases, so does the demand for incorporating these concerns into software. Yet, existing programming language constructs are not well-aligned with concepts of the sustainability domain. This undermines what we term technical sustainability of the software due to (i) increased complexity in programming of such concerns and (ii) continuous code changes to keep up with changes in (environmental, social, legal and other) sustainability-related requirements. In this paper we present a proof-of-concept approach on how technical sustainability support for new and existing concerns can be provided through flexible language-level programming. We propose to incorporate sustainability-related behaviour into programs through micro-languages enabling such behaviour to be updated and/or redefined as and when required.","Title: Choosy and picky: configuration of language product lines\nYear: 2015\n\nAbstract: Although most programming languages naturally share several language features, they are typically implemented as a monolithic product. Language features cannot be plugged and unplugged from a language and reused in another language. Some modular approaches to language construction do exist but composing language features requires a deep understanding of its implementation hampering their use. The choose and pick approach from software product lines provides an easy way to compose a language out of a set of language features. However, current approaches to language product lines are not sufficient enough to cope with the complexity and evolution of real world programming languages. In this work, we propose a general light-weight bottom-up approach to automatically extract a feature model from a set of tagged language components. We applied this approach to the Neverlang language development framework and developed the AiDE tool to guide language developers towards a valid language composition. The approach has been evaluated on a decomposed version of Javascript to highlight the benefits of such a language product line.","Title: Experience of an International Collaborative Project with First Year Programming Students\nYear: 2015\n\nAbstract: This paper describes an Erasmus Intensive Programme that used international collaboration as a novel pedagogical approach to teaching programming skills to first-year students in a blended learning context using a mixture of virtual environment and intensive teaching. The experience and outcomes of the Programme are evaluated from the viewpoints of the students and instructors and conclusions are drawn on the value and conduct of international student collaborations.","Title: Language components for modular DSLs using traits.\nYear: 2016\n\nAbstract: Recent advances in tooling and modern programming languages have progressively brought back the practice of developing domain-specific languages as a means to improve software development. Consequently, the problem of making composition between languages easier by emphasizing code reuse and componentized programming is a topic of increasing interest in research. In fact, it is not uncommon for different languages to share common features, and, because in the same project different DSLs may coexist to model concepts from different problem areas, it is interesting to study ways to develop modular, extensible languages. Earlier work has shown that traits can be used to modularize the semantics of a language implementation; a lot of attention is often spent on embedded DSLs; even when external DSLs are discussed, the main focus is on modularizing the semantics. In this paper we will show a complete trait-based approach to modularize not only the semantics but also the syntax of external DSLs, thereby simplifying extension and therefore evolution of a language implementation. We show the benefits of implementing these techniques using the Scala programming language. HighlightsThe contribution of this work is to synthesize a collection of patterns and techniques that can be used to implement language components, using traits. Separate the syntactic concern from the construction of the abstract representation of the language. Separate the abstract representation of the language from the implementation of its semantics. Modularize the implementation of the semantics in distinct phases; decouple the abstract representation from the semantics of each phase, possibly expressing dependencies between phases. The benefit of representing language concepts through traits is an improved modularization, thereby simplifying code sharing across language implementations. Moreover, since traits in most languages can be written as separate code units, employing them in the modularization of a language make it possible to compile each language component separately and independently from the others, allowing them to be shared as binary assets, that, nevertheless, can be still combined together post-compilation. Scala's trait implementation has been used to demonstrate our contribution.","Title: Formal Attributes Traceability in Modular Language Development Frameworks.\nYear: 2016\n\nAbstract: Modularization and component reuse are concepts that can speed up the design and implementation of domain specific languages. Several modular development frameworks have been developed that rely on attributes to share information among components. Unfortunately, modularization also fosters development in isolation and attributes could be undefined or used inconsistently due to a lack of coordination. This work presents 1) a type system that permits to trace attributes and statically validate the composition against attributes lack or misuse and 2) a correct and complete type inference algorithm for this type system. The type system and inference are based on the Neverlang development framework but it is also discussed how it can be used with different frameworks.","Title: Model-Based Regression Test Selection for Validating Runtime Adaptation of Software Systems\nYear: 2016\n\nAbstract: An increasing number of modern software systems need to be adapted at runtime without stopping their execution. Runtime adaptations can introduce faults in existing functionality, and thus, regression testing must be conducted after an adaptation is performed but before the adaptation is deployed to the running system. Regression testing must be completed subject to time and resource constraints. Thus, test selection techniques are needed to reduce the cost of regression testing. The FiGA framework provides a complete loop from code to models and back that allows fine-grained model-based adaptation and validation of running Java systems without stopping their execution. In this paper we present a model-based test selection approach for regression testing during the validation activity to be used with the FiGA framework. The evaluation results show that our approach was able to reduce the number of selected test cases, and that the model-level fault detection ability of the selected test cases was never lower than that of the original test cases.","Title: Apples and oranges: comparing top-down and bottom-up language product lines.\nYear: 2016\n\nAbstract: Over the past decade language development tools have been significantly improved. This permitted both practitioners and researchers to design a wide variety of domain-specific languages (DSL) and extensions to programming languages. Moreover, multiple researchers have combined different language variants to form families of DSLs as well as programming languages. Unfortunately, current language development tools cannot directly support the development of these families. To overcome this limitation, researchers have recently applied ideas from software product lines (SPL) to create product lines of compilers/interpreters for language families, denoted language product lines (LPL). Similar to SPLs, however, these product lines can be created either using a top-down or a bottom-up approach. Yet, there exist no case study comparing the suitability of both approaches to the development of LPLs, making it unclear how language development tools should evolve. Accordingly, this paper compares both feature modeling approaches by applying them to the development of an LPL for the family of role-based programming languages and discussing their applicability, feasibility and overall suitability for the development of LPLs. Although one might argue that this compares apples and oranges, we believe that this case still provides crucial insights into the requirements, assumptions, and challenges of each approach.","Title: Dodging Unsafe Update Points in Java Dynamic Software Updating Systems\nYear: 2016\n\nAbstract: Dynamic Software Updating (DSU) provides mechanisms to update a program without stopping its execution. An indiscriminate update, that does not consider the current state of the computation, potentially undermines the stability of the running application. To automatically determine a safe moment when to update the running system is still an open problem often neglected from the existing DSU systems. This paper proposes a mechanism to support the choice of a safe update point by marking which point can be considered unsafe and therefore dodged during the update. The method is based on decorating the code with some specific meta-data that can be used to find the right moment to do the update. The proposed approach has been implemented as an external component that can be plugged into every DSU system. The approach is demonstrated on the evolution of the HSQLDB system from two distinct versions to their next update.","Title: Open Programming Language Interpreters.\nYear: 2017\n\nAbstract: Context: This paper presents the concept of open programming language interpreters and the implementation of a framework-level metaobject protocol (MOP) to support them. Inquiry: We address the problem of dynamic interpreter adaptation to tailor the interpreteru0027s behavior on the task to be solved and to introduce new features to fulfill unforeseen requirements. Many languages provide a MOP that to some degree supports reflection. However, MOPs are typically language-specific, their reflective functionality is often restricted, and the adaptation and application logic are often mixed which hardens the understanding and maintenance of the source code. Our system overcomes these limitations. Approach: We designed and implemented a system to support open programming language interpreters. The prototype implementation is integrated in the Neverlang framework. The system exposes the structure, behavior and the runtime state of any Neverlang-based interpreter with the ability to modify it. Knowledge: Our system provides a complete control over interpreteru0027s structure, behavior and its runtime state. The approach is applicable to every Neverlang-based interpreter. Adaptation code can potentially be reused across different language implementations. Grounding: Having a prototype implementation we focused on feasibility evaluation. The paper shows that our approach well addresses problems commonly found in the research literature. We have a demonstrative video and examples that illustrate our approach on dynamic software adaptation, aspect-oriented programming, debugging and context-aware interpreters. Importance: To our knowledge, our paper presents the first reflective approach targeting a general framework for language development. Our system provides full reflective support for free to any Neverlang-based interpreter. We are not aware of any prior application of open implementations to programming language interpreters in the sense defined in this paper. Rather than substituting other approaches, we believe our system can be used as a complementary technique in situations where other approaches present serious limitations.","Title: Context-Aware Software Variability through Adaptable Interpreters.\nYear: 2017\n\nAbstract: A proposed approach moves variability support from the programming language to the language implementation level. This enables contextual variability in any application independently of whether the underlying language supports context-oriented programming. A Neverlang-based prototype implementation illustrates this approach.","Title: μ-DSU: A Micro-Language Based Approach to Dynamic Software Updating.\nYear: 2018\n\nAbstract: •This paper presents μ-DSU a linguistic approach to dynamic software updating (DSU).•The μ-DSU framework is implemented on top of Neverlang. μ-DSU exploits Neverlang’s characteristic to permit a dynamic update of the interpreter during its execution.•μ-DSU has the benefit of easing the introduction and the update of nonfunctional concerns in a running application.•μ-DSU update process leaves the application code untouched reducing the complexity of the updating process and fostering adaptation reuse on a broader scale.•Demonstration studies are provided.","Title: Modular feature-oriented graphical editor product lines.\nYear: 2018\n\nAbstract: Software Product Lines (SPLs) have a long tradition and aim at reducing development costs by increasing reuse. They have been successfully applied to develop families of languages, ultimately establishing the field of Language Product Lines (LPLs). Currently, LPLs facilitate a family of textual languages by defining an SPL of compilers/interpreters. In contrast, this work aims at supporting families of graphical languages by defining an SPL of graphical editors, whereas each language variant is supported by a corresponding product of a Graphical Editor Product Line (GEPL). Thus far, there exists no modular approach for the development of GEPLs for families of visual languages. To remedy this, this paper introduces a feature-oriented development approach for GEPLs that ensures modularity, maintainability, and extensibility of the resulting product line. To showcase the suitability and applicability of our approach, we developed a modular GEPL for the family of role-based modeling languages, a feature rich family of conceptual modeling languages. Finally, we illustrate its extensibility by adding a complex language feature.","Title: AOSD and reflection: benefits and drawbacks to software evolution\nYear: 2006\n\nAbstract: Following last two years' RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop at the ECOOP conference, the RAM-SE 2006 workshop was a successful and popular event. As its name implies, the workshop's focus was on the application of reflective, aspect-oriented and data-mining techniques to the broad field of software evolution. Topics and discussions at the workshop included mechanisms for supporting software evolution, technological limits for software evolution and tools and middleware for software evolution. The workshop's main goal was to bring together researchers working in the field of software evolution with a particular interest in reflection, aspect-oriented programming and meta-data. The workshop was organized as a full day meeting, partly devoted to presentation of submitted position papers and partly devoted to panel discussions about the presented topics and other interesting issues in the field. In this way, the workshop allowed participants to get acquainted with each other's work, and stimulated collaboration. We hope this helped participants in improving their ideas and the quality of their future publications. The workshop's proceedings, including all accepted position papers can be downloaded from the workshop's web site and a post workshop proceeding, including an extension of the accepted paper is published byt the University of Magdeburg. In this report, we first provide a session-by-session overview of the presentations, and then present our opinions about future trends in software evolution.","Title: Viewpoint For Maintaining Uml Models Against Application Changes\nYear: 2006\n\nAbstract: The urgency that characterizes many requests for evolution forces the system administrators/developers of directly adapting the system without passing through the adaptation of its design. This creates a gap between the design information and the system it describes. The existing design models provide a static and often outdated snapshot of the system unrespectful of the system changes. Software developers spend a lot of time on evolving the system and then on updating the design information according to the evolution of the system. To this respect, we present an approach to automatically keep the design information (UML diagrams in our case) updated when the system evolves. The UML diagrams are bound to the application and all the changes to it are reflected to the diagrams as well.","Title: A Fuzzy Logic Based Approach for Model-Based Regression Test Selection\nYear: 2017\n\nAbstract: Regression testing is performed to verify that previously developed functionality of a software system is not broken when changes are made to the system. Since executing all the existing test cases can be expensive, regression test selection (RTS) approaches are used to select a subset of them, thereby improving the efficiency of regression testing. Model-based RTS approaches select test cases on the basis of changes made to the models of a software system. While these approaches are useful in projects that already use model-driven development methodologies, a key obstacle is that the models are generally created at a high level of abstraction. They lack the information needed to build traceability links between the models and the coverage-related execution traces from the code-level test cases. In this paper, we propose a fuzzy logic based approach named FLiRTS, for UML model-based RTS. FLiRTS automatically refines abstract UML models to generate multiple detailed UML models that permit the identification of the traceability links. The process introduces a degree of uncertainty, which is addressed by applying fuzzy logic based on the refinements to allow the classification of the test cases as retestable according to the probabilistic correctness associated with the used refinement. The potential of using FLiRTS is demonstrated on a simple case study. The results are promising and comparable to those obtained from a model-based approach (MaRTS) that requires detailed design models, and a code-based approach (DejaVu).","Title: Supporting inheritance hierarchy changes in model-based regression test selection\nYear: 2019\n\nAbstract: Models can be used to ease and manage the development, evolution, and runtime adaptation of a software system. When models are adapted, the resulting models must be rigorously tested. Apart from adding new test cases, it is also important to perform regression testing to ensure that the evolution or adaptation did not break existing functionality. Since regression testing is performed with limited resources and under time constraints, regression test selection (RTS) techniques are needed to reduce the cost of regression testing. Applying model-level RTS for model-based evolution and adaptation is more convenient than using code-level RTS because the test selection process happens at the same level of abstraction as that of evolution and adaptation. In earlier work, we proposed a model-based RTS approach called MaRTS to be used with a fine-grained model-based adaptation framework that targets applications implemented in Java. MaRTS uses UML models consisting of class and activity diagrams. It classifies test cases as obsolete, reusable, or retestable based on changes made to UML class and activity diagrams of the system being adapted. However, MaRTS did not take into account the changes made to the inheritance hierarchy in the class diagram and the impact of these changes on the selection of test cases. This paper extends MaRTS to support such changes and demonstrates that the extended approach performs as well as or better than code-based RTS approaches in safely selecting regression test cases. While MaRTS can generally be used during any model-driven development or model-based evolution activity, we have developed it in the context of runtime adaptation. We evaluated the extended MaRTS on a set of applications and compared the results with code-based RTS approaches that also support changes to the inheritance hierarchy. The results showed that the extended MaRTS selected all the test cases relevant to the inheritance hierarchy changes and that the fault detection ability of the selected test cases was never lower than that of the baseline test cases. The extended MaRTS achieved comparable results to a graph-walk code-based RTS approach (DejaVu) and showed a higher reduction in the number of selected test cases when compared with a static analysis code-based RTS approach (ChEOPSJ).","Title: Concern-oriented language development (COLD): Fostering reuse in language engineering.\nYear: 2018\n\nAbstract: •Present a new language development model that promotes modularity and reusability.•Promote the development of language concern as reusable piece of language that consists of usual language artifacts (e.g., abstract syntax, concrete syntax, semantics) and exhibits three specific interfaces that support (1) variability management, (2) customization to a specific context, and (3) proper usage of the reused artifact.•The approach is supported by a conceptual model which introduces the required concepts to implement COLD.•We also present concrete examples of some language concerns and the current state of their realization with metamodel-based and grammar-based language workbenches.","Title: Bridging the model-to-code abstraction gap with fuzzy logic in model-based regression test selection\nYear: 2022\n\nAbstract: Regression test selection (RTS) approaches reduce the cost of regression testing of evolving software systems. Existing RTS approaches based on UML models use behavioral diagrams or a combination of structural and behavioral diagrams. However, in practice, behavioral diagrams are incomplete or not used. In previous work, we proposed a fuzzy logic based RTS approach called FLiRTS that uses UML sequence and activity diagrams. In this work, we introduce FLiRTS 2, which drops the need for behavioral diagrams and relies on system models that only use UML class diagrams, which are the most widely used UML diagrams in practice. FLiRTS 2 addresses the unavailability of behavioral diagrams by classifying test cases using fuzzy logic after analyzing the information commonly provided in class diagrams. We evaluated FLiRTS 2 on UML class diagrams extracted from 3331 revisions of 13 open-source software systems, and compared the results with those of code-based dynamic (Ekstazi) and static (STARTS) RTS approaches. The average test suite reduction using FLiRTS 2 was 82.06%. The average safety violations of FLiRTS 2 with respect to Ekstazi and STARTS were 18.88% and 16.53%, respectively. FLiRTS 2 selected on average about 82% of the test cases that were selected by Ekstazi and STARTS. The average precision violations of FLiRTS 2 with respect to Ekstazi and STARTS were 13.27% and 9.01%, respectively. The average mutation score of the full test suites was 18.90%; the standard deviation of the reduced test suites from the average deviation of the mutation score for each subject was 1.78% for FLiRTS 2, 1.11% for Ekstazi, and 1.43% for STARTS. Our experiment demonstrated that the performance of FLiRTS 2 is close to the state-of-art tools for code-based RTS but requires less information and performs the selection in less time.","Title: Towards a recipe for language decomposition: quality assessment of language product lines\nYear: 2022\n\nAbstract: Programming languages are complex systems that are usually implemented as monolithic interpreters and compilers. In recent years, researchers and practitioners gained interest in product line engineering to improve the reusability of language assets and the management of variability-rich systems, introducing the notions of language workbenches and language product lines (LPLs). Nonetheless, language development remains a complex activity and design or implementation flaws can easily waste the efforts of decomposing a language specification into language features. Poorly designed language decompositions result in high inter-dependent components, reducing the variability space of the LPL system and its maintainability. One should detect and fix the design flaws posthaste to prevent these risks while minimizing the development overhead. Therefore, various aspects of the quality of a language decomposition should be quantitatively measurable through adequate metrics. The evaluation, analysis and feedback of these measures should be a primary part of the engineering process of a LPL. In this paper, we present an exploratory study trying to capture these aspects by introducing a design methodology for LPLs; we define the properties of a good language decomposition and adapt a set of metrics from the literature to the framework of language workbenches. Moreover, we leverage the AiDE 2 LPL engineering environment to perform an empirical evaluation of 26 Neverlang-based LPLs based on this design methodology. Our contributions form the foundations of a design methodology for Neverlang-based LPLs. This methodology is comprised of four different elements: i) an engineering process that defines the order in which decisions are made, ii) an integrated development environment for LPL designers and iii) some best practices in the design of well-structured language decomposition when using Neverlang, supported by iv) a variety of LPL metrics that can be used to detect errors in design decisions."],"string":"[\n \"Title: Freely Annotating C#\\nYear: 2005\\n\\nAbstract: Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The annotation model, both in Java and in C#, limits annotations to classes and class members. In this paper we describe [a] C#(a), an extension of the C# programming language, that allows programmers to annotate statements and code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. We also discuss how to use [a] C# to annotate programs giving hints on how to parallelize a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language. Finally, we show how our model for custom attributes has been realized.\",\n \"Title: Reflective Authorization Systems\\nYear: 1998\\n\\nAbstract: A reflective approach for modeling and implementing autho- rization systems is presented. The advantages of the combined use of computational reflection and authorization mechanis ms are discussed, and three reflective architectures are exami ned for pointing out the corresponding merits and defects. Keywords: Authorization, Object-Orientation, Dis- tributed Objects, Reflection, Security.\",\n \"Title: 9th international workshop on aspect-oriented modeling\\nYear: 2006\\n\\nAbstract: This report summarizes the outcomes of the 9th Workshop on Aspect-Oriented Modeling (AOM) held in conjunction with the 9th International Conference on Model Driven Engineering Languages and Systems - MoDELS 2006 - in Genoa, Italy, on the 1st of October 2006. The workshop brought together approximately 25 researchers and practitioners from two communities: aspect-oriented software development and software model engineering. It provided a forum for discussing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, software architecture, detailed design, and mapping to aspect-oriented programming constructs. This paper gives an overview of the accepted submissions and summarizes the results of the different discussion groups. Papers and presentation slides of the workshop are available at http://www.aspect-modeling.org/.\",\n \"Title: @Java: annotations in freedom\\nYear: 2013\\n\\nAbstract: The ability to annotate code and, in general, the capability to attach arbitrary metadata to portions of a program are features that have become more and more common in programming languages. In fact, various programming techniques and tools exploit their explicit availability for a number of purposes, such as extracting documentation, guiding code profiling, enhancing the description of a data type, marking code for instrumentation (for instance, in aspect-oriented frameworks), and the list could go on. While support to attach metadata to code is not a new concept (programming platforms as CLOS and Smalltalk have pioneered in this field), consistent, pervasive APIs to define and manage code annotations are something comparatively recent on modern platforms like the .NET and Java. Annotations in Java make possible to attach custom, structured metadata to declarations of classes, fields and methods. With this work, we propose an extension to Java (named @Java) that has a richer annotation model, supporting code block and expression annotations. In other words, the granularity of annotations extends to the statement and expression level and does not limit to class, method and field declarations.\",\n \"Title: Static header as sentinel\\nYear: 1998\\n\\nAbstract: Writing code to handle dynamic data structures might seem to be an easy task, but write an efficient, readable and maintainable code is not such a simple task.In this short note we investigate some problems in developing code for handling dynamic data structures, and we propose techniques to overcome them. We take into account the interesting method proposed by Qiu in SIGPLAN Notices [3].Many authors have addressed the problem of handling dynamic data structures by suggesting several clever tricks to simplify dynamic data structures management [4, 2] and to avoid the non-uniform behavior of empty data structures, and access to the first and the last element. In particular, the use of data sentinels and dummy headers makes the implementation more orthogonal and easy to maintain. The cost is a slightly increased size in space which is negligible when compared with the benefits produced.\",\n \"Title: Sectional domain specific languages\\nYear: 2009\\n\\nAbstract: Nowadays, many problems are solved by using a domain specific language (DSL), i.e., a programming language tailored to work on a particular application domain. Normally, a new DSL is designed and implemented from scratch requiring a long time-to-market due to implementation and testing issues. Whereas when the DSL simply extends another language it is realized as a source-to-source transformation or as an external library with limited flexibility. The Hive framework is developed with the intent of overcoming these issues by providing a mechanism to compose different programming features together forming a new DSL, what we call a sectional DSL. The support (both at compiler and interpreter level) of each feature is separately described and easily composed with the others. This approach is quite flexible and permits to build up a new DSL from scratch or simplifying an existing language without penalties. Moreover, it has the desirable side-effect that each DSL can be extended at any time potentially also at run-time.\",\n \"Title: Self-Evolving Petri Nets\\nYear: 2007\\n\\nAbstract: Nowadays, software evolution is a very hot topic. It is particularly complex when it regards critical and nonstopping systems. Usually, these situations are tackled by hard- coding all the foreseeable evolutions in the application design and code. Neglecting the obvious difficulties in pursuing this approach, we also get the application code and design polluted with details that do not regard the current system functionality, and that hamper design analysis, code reuse and application maintenance in general. Petri Nets ( PN), as a formalism for modeling and designing distributed/concurrent software systems, are not exempt from this issue. The goal of this work is to propose a PN based reflective framework that lets everyone model a system able to evolve, keeping separated functional aspects from evolutionary ones and applying evolution to the model only if necessary. Such an approach tries to keep system's model as simple as possible, preserving ( and exploiting) ability of formally verifying system properties typical of PN, granting at the same time adaptability.\",\n \"Title: Neverlang 2: a framework for modular language implementation\\nYear: 2014\\n\\nAbstract: Neverlang 2 is a JVM-based framework for language development that emphasizes code reuse through composition of language features. This paper is aimed at showing how to develop extensible, custom languages using Neverlang's component-based model of implementation. Using this model, each feature of the language can be implemented as a separate, conceptually isolated unit that can be compiled and distributed separately from the others. A live tutorial of the framework can be found at http://youtu.be/Szxvg7XLbXc\",\n \"Title: Report of the 14th International Workshop on Aspect-Oriented Modeling\\nYear: 2010\\n\\nAbstract: This report summarizes the outcome of the 14th Workshop on Aspect-Oriented Modeling (AOM), as part of the 12th International Conference on Model Driven Engineering Languages and Systems MoD-ELS 2009 in Denver, Colorado, USA, on the 4th of October 2009. The workshop brought together researchers and practitioners from two communities: aspect-oriented software development (AOSD) and software model engineering. This paper gives an overview of the accepted submissions, and summarizes the results of the discussion.\",\n \"Title: @Java: Bringing a richer annotation model to Java.\\nYear: 2014\\n\\nAbstract: The ability to annotate code and, in general, the capability to attach arbitrary meta-data to portions of a program are features that have become more and more common in programming languages.\",\n \"Title: Guest editors' introduction: aspects and software evolution\\nYear: 2007\\n\\nAbstract: Software evolution and adaptation is a research area, as also the name states, in continuous evolution, that offers stimulating\\n challenges for both academic and industrial researchers. The evolution of software systems, to face unexpected situations\\n or just for improving their features, relies on software engineering techniques and methodologies, that often imply re-designing,\\n refactoring and re-coding part of or the whole system. Nowadays, similar approaches are not applicable in all situations (e.g.,\\n for evolving non-stopping systems or systems whose code is not available) and different approaches are necessary.\",\n \"Title: SmartMethod: an efficient replacement for method\\nYear: 2004\\n\\nAbstract: In the last few years the interest in reflection has grown and many modern programming languages/architectures have provided the programmer with reflective mechanisms. As well as any other novelty also reflection has detractors. They rightly or wrongly accuse reflection to be too inefficient to be used with real profit. In this work, we have investigated about the performance of Java reflection library (especially of the class Method and of its method invoke) and realized a mechanism which improves its performances. Our mechanism consists of a class, named SmartMethod and of a parser contributing to transform reflective invocations into direct call carried out by the standard invocation mechanism of Java. The SmartMethod class is compliant --- that is, it provides exactly the same services ---, with the class Method of the standard Java core reflection library but it provides a more efficient reflective method invocation.\",\n \"Title: Getting Farther on Software Evolution via AOP and Reflection\\nYear: 2008\\n\\nAbstract: Following last four years' RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop at the ECOOP conference, the RAM-SE'08 workshop was a successful and popular event. As its name implies, the workshop's focus was on the application of reflective, aspect-oriented and data-mining techniques to the broad field of software evolution. Topics and discussions at the workshop included mechanisms for supporting software evolution, technological limits of the aspect-oriented and reflective approaches to software evolution and tools devoted to software evolution. The workshop's main goal was to bring together researchers working in the field of software evolution with a particular interest in reflection, aspect-oriented programming and meta-data. The workshop was organized as a full day meeting, partly devoted to presentation of submitted position papers and partly devoted to panel discussions about the presented topics and other interesting issues in the field. In this way, the workshop allowed participants to get acquainted with each other's work, and stimulated collaboration. We hope this helped participants in improving their ideas and the quality of their future publications. The workshop's proceedings, including all accepted position papers can be downloaded from the workshop's web site and a post workshop proceeding, including an extension of the accepted paper is planned to be published by the University of Magdeburg. In this report, we provide a session-by-session overview of the workshop, and then present our opinions about future trends in software evolution.\",\n \"Title: Evolving Pointcut Definition to Get Software Evolution\\nYear: 2004\\n\\nAbstract: In this paper, we have briefly analyzed the aspect-oriented approach with respect to the software evolution topic. The aim of this analysis is to high- light the aspect-oriented potentiality for software evolution and its limits. From our analysis, we can state that actual pointcut definition mechanisms are not enough expressive to pick out from design information where software evolu- tion should be applied. We will also give some suggestions about how to improve the pointcut definition mechanism.\",\n \"Title: Evaluation of Object-Oriented Reflective Models\\nYear: 1998\\n\\nAbstract: In this paper we explore the object-oriented reflective world, performing an overview of the existing models and presenting a set of features suitable to evaluate the quality of each reflective model. The purpose of the pa- per is to determine the context applicability of each re- flective model examined.\",\n \"Title: Recognizing join points from their context through graph grammars\\nYear: 2009\\n\\nAbstract: Aspect-oriented software development has been proposed with the intent of better modularizing object-oriented programs by confining crosscutting concerns in aspects. Unfortunately, the aspects do not completely keep their promises. Most of the current approaches revealed to be tightly coupled with the base-program's code compromising the modularity. Moreover, the feasible modularization has a coarse-grain since the aspects can only be woven at the public interface level but not on a generic statement. We have designed the Blueprint framework to overcome these limits. The join points are located through the description of the context where they could be found. This work is about the framework realization and the role that graph grammars play in locating the join points in the base-program from the context description.\",\n \"Title: A Reflective PN-Based Approach to Dynamic Workflow Change\\nYear: 2007\\n\\nAbstract: The design of dynamic workflows needs adequate modeling/specification formalisms and tools to soundly handle possible changes occurring during workflow operation. A common approach is to pollute design with details that do not regard the current workflow behavior, but rather its evolution. That hampers analysis, reuse and maintenance in general. We propose and discuss the adoption of a recent Petri Net based reflective model (based on classical PN) as a support to dynamic workflow design, by addressing a localized problem: how to determine what tasks should be redone and which ones do not when transferring a workflow instance from an old to a new template. Behind there is the idea that keeping functional aspects separated from evolutionary ones, and applying evolution to the (current) workflow template only when necessary, results in a simple reference model on which the ability of formally verifying typical workflow properties is preserved, thus favoring a dependable adaptability. Keywords: Dynamic Workflow, Petri Nets, Reflection, Evolution.\",\n \"Title: Smart Data Caching in Archeological Wireless Applications: the PAST Solution\\nYear: 2003\\n\\nAbstract: Wireless computing, because of the limited memory capacity of the palmtops, forces to separate data (stored on a remote server) from the application (running on the palmtops) that uses them. In applications working on data that frequently change, several kilobytes of data are exchanged between the server and the client palmtops. It is fairly evident that a similar tight coupling may easily saturate the network bandwidth when many palmtops are used in parallel, thus degrading the performances of the application running on it. This paper shows a way to reduce the waste of bandwidth by exploiting at the best the palmtop memory to deal with data caching. The proposed smart data caching is based on context information. We have also applied our method and analyzed its features in a specific application: electronic guide to archeological sites in the PAST EC IT project.\",\n \"Title: Reflective authorization systems: possibilities, benefits, and drawbacks\\nYear: 1999\\n\\nAbstract: We analyze how to use the reflective approach to integrate an authorization system into a distributed object-oriented framework. The expected benefits from the reflective approach are: more stability of the security layer (i.e., with a more limited number of hidden bugs), better software and development modularity, more reusability, and the possibility to adapt the security module with at most a few changes to other applications. Our analysis is supported by simple and illustrative examples written in Java.\",\n \"Title: The Role of Design Information in Software Evolution\\nYear: 2005\\n\\nAbstract: Software modeling has received a lot a of attention in the last decade and now is an important support for the design process. Actually, the design process is very important to the usability and understandability of the system, for example functional requirements present a complete description of how the system will function from the user's perspec- tive, while non-functional requirements dictate properties and impose constraints on the project or system. The design models and implementation code must be strictly connected, i.e. we must have correlation and con- sistency between the two views, and this correlation must exist during all the software cycle. Often, the early stages of development, the specifications and the design of the system, are ignored once the code has been devel- oped. This practice cause a lot of problems, in particular when the system must evolve. Nowadays, to maintain a software is a difficult task, since there is a high coupling degree between the software itself and its environment. Often, changes in the environment cause changes in the software, in other words, the system must evolve itself to follow the evolution of its environment. Typically, a design is created initially, but as the code gets written and modified, the design is not updated to reflect such changes. This paper describes and discusses how the design information can be used to drive the software evolution and consequently to maintain consistence among design and code.\",\n \"Title: RAMSES: a Reflective Middleware for Software Evolution\\nYear: 2004\\n\\nAbstract: Software systems today need to dynamically self-adapt against dynamic requirement changes. In this paper we describe RAMSES a reflective middleware whose aim consists of consistently evolving software systems against runtime changes. This middleware provides the ability to change both structure and behavior for the base-level system at run-time by using its design information. The meta-level is composed of cooper- ating objects, and has been specified by using a design pattern language. The base objects are controlled by meta-objects that drive their evolution. The essence of RAMSES is the ability of extracting the design data from the base application, and of constraining the dynamic evolution to stable and consistent systems.\",\n \"Title: Shifting Up Reflection from the Implementation to the Analysis Level\\nYear: 1999\\n\\nAbstract: Traditional methods for object-oriented analysis and modeling focus on the functional specification of software systems, i.e., application domain modeling. Non-functional requirements such as fault-tolerance, distribution, integration with legacy systems, and so on, have no clear collocation within the analysis process, since they are related to the architecture and workings of the system itself rather than the application domain. They are thus addressed in the system's design, based on the partitioning of the system's functionality into classes resulting from analysis. As a consequence, the smooth transition from analysis to design that is usually celebrated as one of the main advantages of the object-oriented paradigm does not actually hold for what concerns non-functional issues. A side effect is that functional and nonfunctional concerns tend to be mixed at the implementation level. We argue that the reflective approach whereby non-functional properties are ascribed to a meta-level of the software system may be extended \\\"back to\\\" analysis. Adopting a reflective approach in object-oriented analysis may support the precise specification of non-functional requirements in analysis and, if used in conjunction with a reflective approach to design, recover the smooth transition from analysis to design in the case of nonfunctional system's properties.\",\n \"Title: Implementing the essence of reflection: a reflective run-time environment\\nYear: 2004\\n\\nAbstract: Computational reflection provides the developers with a programming mechanism devoted to favorite code extensibility, reuse and maintenance. Notwithstanding that, it has not achieved developers' unanimous acceptance and its full potential yet. In our opinion, this depends on the intrinsic complexity of most of the reflective approaches that hinders their efficient implementation. The aim of this paper consists of defining the essence of reflection, that is, to identify the minimal set of characteristics that a software system must have to be considered reflective. The consequence is the realization of a run-time environment supporting the essence of reflection without affecting the programming language and with a minimal impact on the programming system design. This achievement will improve reflective system performances reducing the impact of one of the most diffuse criticism about reflection: low performance.\",\n \"Title: Towards a colored reflective Petri-net approach to model self-evolving service-oriented architectures\\nYear: 2012\\n\\nAbstract: Service-based software systems could require to evolve during their execution. To support this, we need to consider system evolving since the design phase. Reflective Petri nets separate the system from its evolution by describing it and how it can evolve. However, reflective Petri nets have some expressivity limits and render overcomplicated the consistency checking necessary during service evolution. In this paper, we extend the reflective Petri nets approach to overcome such limits and show that on a case study.\",\n \"Title: Context traits: dynamic behaviour adaptation through run-time trait recomposition\\nYear: 2013\\n\\nAbstract: Context-oriented programming emerged as a new paradigm to support fine-grained dynamic adaptation of software behaviour according to the context of execution. Though existing context-oriented approaches permit the adaptation of individual methods, in practice behavioural adaptations to specific contexts often require the modification of groups of interrelated methods. Furthermore, existing approaches impose a composition semantics that cannot be adjusted on a domain-specific basis. The mechanism of traits seems to provide a more appropriate level of granularity for defining adaptations, and brings along a flexible composition mechanism that can be exploited in a dynamic setting. This paper explores how to achieve context-oriented programming by using traits as units of adaptation, and trait composition as a mechanism to introduce behavioural adaptations at run time. First-class contexts reify relevant aspects of the environment in which the application executes, and they directly influence the trait composition of the objects that make up the application. To resolve conflicts arising from dynamic composition of behavioural adaptations, programmers can explicitly encode composition policies. With all this, the notion of context traits offers a promising approach to implementing dynamically adaptable systems. To validate the context traits model we implemented a JavaScript library and conducted case studies on context-driven adaptability.\",\n \"Title: On The Footprints Of Join Points: The Blueprint Approach\\nYear: 2007\\n\\nAbstract: Aspect-oriented techniques are widely used to better modularize object-oriented programs by introducing crosscutting concerns in a safe and non-invasive way, i.e., aspect-oriented mechanisms better address the modularization of functionality that orthogonally crosscuts the implementation of the application.Unfortunately, as noted by several researchers, most of the current aspect-oriented approaches are too coupled with the application code, and this fact hinders the concerns separability and consequently their re-usability since each aspect is strictly tailored on the base application. Moreover, the join points (i.e., locations affected by a crosscutting concerns) actually are defined at the operation level. It implies that the possible set of join points includes every operation (e.g., method invocations) that the system performs. Whereas, in many contexts we wish to define aspects that are expected to work at the statement level, i.e., by considering as a join point every point between two generic statements (i.e., lines of code).In this paper, we present our approach, called Blueprint, to overcome the above-mentioned limitations of the current aspect-oriented approaches. The Blueprint consists of a new aspect-oriented programming language based on modeling the join point selection mechanism at a high-level of abstraction to decouple aspects from the application code. To this regard, we adopt a high-level pattern-based join point model, where join points are described by join point blueprints, i.e., behavioral patterns describing where the join points should be found.\",\n \"Title: Architectural Reflection: Realising Software Architectures via Reflective Activities\\nYear: 2000\\n\\nAbstract: Architectural reflection is the computation performed by a software system about its own software architecture. Building on previous research and on practical experience in industrial projects, in this paper we expand the approach and show a practical (albeit very simple) example ofa pplication of architectural reflection. The example shows how one can express, thanks to reflection, both functional and nonfunctional requirements in terms ofob ject-oriented concepts, and how a clean separation ofcon cerns between application domain level and architectural level activities can be enforced.\",\n \"Title: Rule-Based Strategic Reflection: Observing and Modifying Behavior at the Architectural Level\\nYear: 1999\\n\\nAbstract: As software systems become larger and more complex, a relevant part of code shifts from the application domain to the management of the system's run-time architecture (e.g., substituting components and connectors for run-time automated tuning). We propose a novel design approach for component-based systems supporting architectural management in a systematic and conceptually clean way and allowing for the transparent addition of architectural management functionality to existing systems. The approach builds on the concept of reflection, extending it to the programming-in-the-large level, thus yielding architectural reflection (AR). This paper focuses on one aspect of AR, namely the monitoring and dynamic modification of the system's overall control structure (strategic reflection), which allows the behaviour of a system to be monitored and adjusted without modifying the system itself.\",\n \"Title: Aspect-oriented procedural content engineering for game design\\nYear: 2009\\n\\nAbstract: Generally progressive procedural content in the context of 3D scene rendering is expressed as recursive functions where a finer level of detail gets computed on demand. Typical examples of content procedurally generated are fractal images and noise textures. Unfortunately, not always the content can be expressed in this way, developers and content creators need the data to have some peculiarity (like windows on a wall for a house 3D model) and a method to drive data simplification without losing relevant details. In this paper we discuss how aspect oriented (AO) techniques can be used to drive the content creation process by mapping each data peculiarity to the code to generate it. Using aspects will let us to partially evaluate the code of the procedure improving the performance without losing the flow of the generation logic. We will also discuss how the use of AO can provide techniques to build simplified version of the data through code transformations.\",\n \"Title: AOP for software evolution: a design oriented approach\\nYear: 2005\\n\\nAbstract: In this paper, we have briefly explored the aspect-oriented approach as a tool for supporting the software evolution. The aim of this analysis is to highlight the potentiality and the limits of the aspect-oriented development for software evolution. From our analysis follows that in general (and in particular for AspectJ) the approach to join points, pointcuts and advices definition are not enough intuitive, abstract and expressive to support all the requirements for carrying out the software evolution. We have also examined how a mechanism for specifying pointcuts and advices based on design information, in particular on the use of UML diagrams, can better support the software evolution through aspect oriented programming. Our analysis and proposal are presented through an example.\",\n \"Title: 11th International Workshop on Aspect-Oriented Modeling\\nYear: 2007\\n\\nAbstract: This report summarizes the results and discussions from the 11th Workshop on Aspect-Oriented Modeling (AOM). The workshop was held in conjunction with the International Conference on Model-Driven Engineering, Languages, and Systems (MODELS), which was located in Nashville, Tennes-see, on September 30, 2007. Over 20 researchers and practitioners attended the workshop with various backgrounds in aspect-oriented software development and software model engineering. The workshop provided a forum for discuss-ing the state of the art in modeling crosscutting concerns at different stages of the software development process: requirements elicitation and analysis, soft-ware architecture, detailed design, and mapping to aspect-oriented programm-ing constructs. This workshop summary provides an overview of the accepted submissions and summarizes the results of the different discussion groups. Papers, presentation slides, and photos from the workshop are available at http://www.aspect-modeling.org/.\",\n \"Title: Fine-Grained Software Evolution Using UML Activity and Class Models.\\nYear: 2013\\n\\nAbstract: Modern software systems that play critical roles in society's infrastructures are often required to change at runtime so that they can continuously provide essential services in the dynamic environments they operate in. Updating open, distributed software systems at runtime is very challenging. Using runtime models as an interface for updating software at runtime can help developers manage the complexity of updating software while it is executing. In this work we describe an approach to updating Java software at runtime through the use of runtime models consisting of UML class and activity diagrams. Changes to models are turned into changes on Java source code, which is then propagated to the runtime system using the JavAdaptor technology. In particular, the presented approach permits in-the-small software changes, i.e., changes at the code statement level, as opposed to in-the-large changes, i.e., changes at the component level. We present a case study that demonstrates the major aspects of the approach and its use.\",\n \"Title: Remote method invocation as a first-class citizen\\nYear: 2003\\n\\nAbstract: The classical remote method invocation (RMI) mechanism adopted by several object-based middleware is 'black-box' in nature, and the RMI functionality, i.e., the RMI interaction policy and its configuration, is hard-coded into the application. This RMI nature hinders software development and reuse, forcing the programmer to focus on communication details often marginal to the application being developed. Extending the RMI behavior with extra functionality is also a very difficult job, because added code must be scattered among the entities involved in communications.This situation could be improved by developing the system in several separate layers, confining communications and related matters to specific layers. As demonstrated by recent work on reflective middleware, reflection represents a powerful tool for realizing such a separation and therefore overcoming the problems referred to above. Such an approach improves the separation of concerns between the communication-related algorithms and the functional aspects of an application. However, communications and all related concerns are not managed as a single unit that is separate from the rest of the application, which makes their reuse, extension, and management difficult. As a consequence, communications concerns continue to be scattered across the meta-program, communication mechanisms continue to be black-box in nature, and there is only limited opportunity to adjust communication policies through configuration interfaces.In this paper we examine the issues raised above, and propose a reflective approach specially designed to open up the Java RMI mechanism. Our proposal consists of a new reflective model, called multi-channel reification, that reflects on and reifies communication channels, i.e., it renders communication channels first-class citizens. This model is designed both for developing new communication mechanisms and for extending the behavior of communication mechanisms provided by the underlying system. Our approach is embodied in a framework called mChaRM, which is described in detail in this paper.\",\n \"Title: Reflective Analysis and Design for Adapting Object Run-Time Behavior\\nYear: 2002\\n\\nAbstract: Today, complex information systems need a simple way for changing the object behavior according with changes that occur in its running environment. We present a reflective architecture which provides the abilityt o change object behavior at run-time by using design-time information. By integrating reflection with design patterns we get a flexible and easilyad aptable architecture. A reflective approach that describes object model, scenarios and statecharts helps to dynamically adapt the software system to environmental changes. The object model, system scenario and manyot her design information are reified by spe cial meta-objects, named evolutionary meta-objects. Evolutionary meta-objects deal with two types of run-time evolution. Structural evolution is carried out bycau sal connection between evolutionary meta-objects and its referents through changing the structure of these referents by adding or removing objects or relations. Behavioral evolution allows the system to dynamically adapt its behavior to environment changes by itself. Evolutionarym eta-objects react to environment changes for adapting the information theyh ave reified and steering the system evolution. They provide a natural liaison between design information and the system based on such information. This paper describes how this liaison can be built and how it can be used for adapting a running system to environment changes.\",\n \"Title: A Petri-Net Based Reflective Framework for the Evolution of Dynamic Systems\\nYear: 2006\\n\\nAbstract: Nowadays, software evolution is a very hot topic. Many applications need to be updated or extended with new characteristics during their lifecycle. Software evolution is characterized by its huge cost and slow speed of implementation. Often, software evolution implies a redesign of the whole system, the development of new features and their integration in the existing and/or running systems (this last step often implies a complete rebuilding of the system). A good evolution is carried out through the evolution of the system design information and then propagating the evolution to the implementation. Petri Nets (PN), as a formalism for modeling and designing distributed/concurrent software systems, are not exempt from this issue. Several times a system modeled through Petri nets has to be updated and consequently also the model should be updated. Often, some kinds of evolution are foreseeable and could be hardcoded in the code or in the model, respectively. Embedding evolutionary steps in the model or in the code however requires early and full knowledge of the evolution. The model itself should be augmented with details that do not regard the current system functionality, and that jeopardize or make very hard analysis and verification of system properties. In this work, we propose a PN based reflective framework that lets everyone model a system able to evolve, keeping separated functional aspects from evolutionary ones and applying evolution to the model if necessary. Such an approach tries to keep the model as simple as possible, preserving (and exploiting) the ability of formally verifying system properties typical of PN, granting at the same time model adaptability.\",\n \"Title: Fine-grained annotations for pointcuts with a finer granularity\\nYear: 2013\\n\\nAbstract: A number of authors have suggested that AspectJ-like pointcut languages are too limited, and that they cannot select every possible join point in a program. Many enhanced pointcut languages have been proposed; they require virtually no change to the original code, but their improved expressive power comes often at the cost of making the pointcut expression too tightly connected with the structure of the programs that are being advised. Other solutions consist in simple extensions to the base language; they require only small changes to the original code, but they frequently serve no other immediate purpose than exposing pieces of code to the weaver. Annotations are a form of metadata that has been introduced in Java 5. Annotations have a number of uses: they may provide hints to the compiler, information to code processing tools and they can be retained at runtime. At the moment of writing, runtime-accessible annotations in the Java programming language can only be applied to classes, fields and methods. The support to annotate expressions and blocks feels like a natural extension to Java's annotation model, that can be also exploited to expose join points at a finer-grained level. In this paper we present an extension to the AspectJ language to select block and expression annotations in the @Java language extension.\",\n \"Title: Design-Based Pointcuts Robustness Against Software Evolution\\nYear: 2006\\n\\nAbstract: Aspect-Oriented Programming (AOP) is a powerful technique to better modularize object-oriented programs by introducing crosscutting concerns in a safe and noninvasive way. Unfortunately, most of the current join point models are too coupled with the application code. This fact harms the evolvability of the program, hinders the concerns selection and reduces the aspect reusability. To overcome this problem is an hot topic. This work propose a possible solution to the limits of the current aspect-oriented techniques based on model- ing the join point selection mechanism at a higher level of abstraction to decoupling base program and aspects. In this paper, we will present by examples a novel join point model based on design information (e.g., ex- pressed through UML diagrams). Design information provides an high-level view on the application structure and behavior decoupled by base program. A design oriented join point model will render aspect definition more robust against base program evolution, reusable and independent of the base program.\",\n \"Title: Join point patterns: a high-level join point selection mechanism\\nYear: 2006\\n\\nAbstract: Aspect-Oriented Programming is a powerful technique to better modularize object-oriented programs by introducing crosscutting concerns in a safe and noninvasive way. Unfortunately, most of the current join point models are too coupled with the application code. This fact hinders the concerns separability and reusability since each aspect is strictly tailored on the base application. This work proposes a possible solution to this problem based on modeling the join points selection mechanism at a higher level of abstraction. In our view, the aspect designer does not need to know the inner details of the application such as a specific implementation or the used name conventions rather he exclusively needs to know the application behavior to apply his/her aspects. In the paper, we present a novel join point model with a join point selection mechanism based on a high-level program representation. This high-level view of the application decouples the aspects definition from the base program structure and syntax. The separation between aspects and base program will render the aspects more reusable and independent of the manipulated application.\",\n \"Title: AOP-HiddenMetrics: Separation, Extensibility and Adaptability in SW Measurement\\nYear: 2008\\n\\nAbstract: Traditional approaches to dynamic system analysis and metrics measurement are based on system code (both source, intermediate and executable code) instrumentation or need ad hoc support by the run-time environment. In these contexts, the measurement process is tricky, invasive and the results could be affected by the process itself making the data not germane. Moreover, the tool based on these approaches are difficult to customize, extend and often use since their properties are rooted at specific system details (e.g., special tools such as bytecode analyzers or virtual machine goodies such as the debugger interface) and require high efforts, skills and knowledges to be adapted. Notwithstanding its importance, software measurement is clearly a nonfunctional con- cern and should not impact on the software development and efficiency. Aspect- oriented programming provides the mechanisms to deal with this kind of concern and to overcome the software measurement limitations. In this paper, we present a different approach to dynamic software measurements based on aspect-oriented programming and the corresponding support framework named AOPÂHiddenMetrics. The proposed approach makes the measurement process highly customizable and easy to use reducing its invasiveness and the dependency from the code knowledge.\",\n \"Title: JavAdaptor: unrestricted dynamic software updates for Java\\nYear: 2011\\n\\nAbstract: Dynamic software updates (DSU) are one of the top-most features requested by developers and users. As a result, DSU is already standard in many dynamic programming languages. But, it is not standard in statically typed languages such as Java. Even if at place number three of Oracle's current request for enhancement (RFE) list, DSU support in Java is very limited. Therefore, over the years many different DSU approaches for Java have been proposed. Nevertheless, DSU for Java is still an active field of research, because most of the existing approaches are too restrictive. Some of the approaches have shortcomings either in terms of flexibility or performance, whereas others are platform dependent or dictate the program's architecture. With JavAdaptor, we present the first DSU approach which comes without those restrictions. We will demonstrate JavAdaptor based on the well-known arcade game Snake which we will update stepwise at runtime.\",\n \"Title: Variability Support in Domain-Specific Language Development.\\nYear: 2013\\n\\nAbstract: Domain Specific Languages (DSLs) are widely adopted to capitalize on business domain experiences. Consequently, DSL development is becoming a recurring activity. Unfortunately, even though it has its benefits, language development is a complex and time-consuming task. Languages are commonly realized from scratch, even when they share some concepts and even though they could share bits of tool support. This cost can be reduced by employing modern modular programming techniques that foster code reuse. However, selecting and composing these modules is often only within the reach of a skilled DSL developer. In this paper we propose to combine modular language development and variability management, with the objective of capitalizing on existing assets. This approach explicitly models the dependencies between language components, thereby allowing a domain expert to configure a desired DSL, and automatically derive its implementation. The approach is tool supported, using Neverlang to implement language components, and the Common Variability Language (CVL) for managing the variability and automating the configuration. We will further illustrate our approach with the help of a case study, where we will implement a family of DSLs to describe state machines.\",\n \"Title: Visualizing and Managing Network Topologies via Rectangular Dualization\\nYear: 2006\\n\\nAbstract: Rectangular dualization is an effective, hierarchically oriented visualization method for network topologies and can be used in many other problems having in common with networks the condition that objects and their interoccurring relations are represented by means of a planar graph. However, only 4-connected triangulated planar graphs admit a rectangular dual. In this paper we present a linear time algorithm to optimally construct a rectangular layout for a general class of graphs and we discuss a variety of application fields where this approach represents an helpful support for visualization tools.\",\n \"Title: Software evolution: a trip through reflective, aspect, and meta-data oriented techniques\\nYear: 2004\\n\\nAbstract: Previous workshops related to aspect oriented software development, reflection organized at previous ECOOP conferences (e.g., RMA'00. and AOMMeT'01. ) and conferences on the same topics (Reflection'01 and AOSD since 2002) have pointed out the growing interest on these topics and their relevance in the software evolution as techniques for code instrumentation. Very similar conclusions can be drawn by reading the contributions to the workshops on unanticipated software evolution (USE 2002 and USE 2003. ). Following the example provided by these venues, the RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop has provided an opportunity for researchers with a broad range of interests in reflective techniques and aspect-oriented software development to discuss recent developments of such a techniques in application to the software evolution. The workshop main goal was to encourage people to present works in progress. These works could cover all the spectrum from theory to practice. To ensure creativity, originality, and audience interests, participants have been selected by the workshop organizers on the basis of 5-page position paper. We hope that the workshop will help them to mature their ideas and to improve the quality of their future publications based on the presented work. The workshop proceedings are available as research report C-186 of the Department of Mathematical and Computing Sciences of the Tokyo Institute of Technology and freely downlodable from the workshop web site.\",\n \"Title: SmartReflection: Efficient Introspection in Java\\nYear: 2004\\n\\nAbstract: In the last few years the interest in reflection has grown and many modern programming languages/environments (e.g., Java and .NET) have provided the programmer with reflective mechanisms, i.e., with the ability of dynamically looking into (introspect) the structure of the code from the code itself. In spite of its evident usefulness, reflection has many detractors, who claim that it is too inecient to be used with real profit. In this work, we have investigated about the performance issue in the context of the Java reflection library and presented a dierent approach to the introspection in Java that improves its performances. The basic idea of the proposed approach consists of moving most of the overhead due to the dynamic introspection from run-time to compile- time. The eciency improvement has been proved by providing a new reflection library compliant - that is, it provides exactly the same services -, with the standard Java reflection library based on the proposed approach. This paper is focused on speeding up the reification and the invocation of methods, i.e., on the class SmartMethod that replaces the class Method of the standard reflection library.\",\n \"Title: Seamless Nomadic System-Aware Servants\\nYear: 2004\\n\\nAbstract: The growing diffusion of wireless technologies is leading to deployment of small-scale and location dependent information services (LDISs). Those new services call for provisioning schemes that are able to operate in a distributed environment and do not require networkinfrastructure. This paper describes an approach to a service-oriented middleware which enables a mobile device to be aware of the surrounding environment and to transparently exploit every LDIS discovered in the coverage area of the hosting wireless network. the paperintroduces seamless nomadic system-aware (SNA) servant. SNA servants run on mobile devices, discover LDISs and are not associated with any specific service. The paper also describes the key features for the SNA servants implementation and for rendering them interoperable and cross-platform on, at least, .NET and JVM frameworks.\",\n \"Title: Towards a model-driven join point model\\nYear: 2006\\n\\nAbstract: Aspect-Oriented Programming (AOP) is increasingly being adopted by developers to better modularize object-oriented design by introducing crosscutting concerns. However, due to tight coupling of existing approaches with the implementing code and to the poor expressiveness of the pointcut languages a number of problems became evident. We believe that such problems could be solved shifting the focus of software development from a programming language specific implementation to application design. This work presents a possible solution based on modeling aspects at a higher level of abstraction which are, in turn, transformed to specific targets.\",\n \"Title: Evolving System's Modeling and Simulation through Reflective Petri Nets\\nYear: 2009\\n\\nAbstract: The design of dynamic discrete-event systems calls for adequate modeling formalisms and tools to manage possible changes occurring during system's lifecycle. A common approach is to pollute design with details that do not regard the current system behavior rather its evolution. That hampers analysis, reuse and maintenance in general. A reflective Petri net model (based on classical Petri nets) was recently proposed to support dynamic discrete-event system's design, and was applied to dynamic workflow's management. Behind there is the idea that keeping functional aspects separated from evolutionary ones and applying them to the (current) system only when necessary, results in a simple formal model on which the ability of verifying properties typical of Petri nets is preserved. In this paper we provide the reflective Petri nets with a (labeled) state-transition graph semantics.\",\n \"Title: (Symbolic) state-space inspection of a class of dynamic Petri nets\\nYear: 2010\\n\\nAbstract: The design of dynamic or adaptable discrete-event systems needs for adequate modeling techniques in order to manage possible structural changes occurring during system's lifecycle. An usual approach is that of polluting design with details not concerning the (current) system behavior, rather its evolution. That hampers analysis, reuse and maintenance in general. A Petri net-based reflective layout based on classical Petri nets was recently proposed to support dynamic discrete-event system's design, and was applied to dynamic workflows. The basic idea is that keeping functional aspects separated from evolutionary ones, deploying evolution on the (current) system configuration when necessary, results in a clean formal model for dynamic systems. This model preserves the ability of verifying properties typical of classical Petri nets. As a first step toward the implementation of a discrete-event simulator, Reflective Petri nets are provided with a (symbolic) reduced state-transition graph.\",\n \"Title: JavAdaptor-Flexible runtime updates of Java applications\\nYear: 2013\\n\\nAbstract: AbstractSoftware is changed frequently during its life cycle. New requirements come, and bugs must be fixed. To update an application, it usually must be stopped, patched, and restarted. This causes time periods of unavailability, which is always a problem for highly available applications. Even for the development of complex applications, restarts to test new program parts can be time consuming and annoying. Thus, we aim at dynamic software updates to update programs at runtime. There is a large body of research on dynamic software updates, but so far, existing approaches have shortcomings either in terms of flexibility or performance. In addition, some of them depend on specific runtime environments and dictate the program's architecture. We present JavAdaptor, the first runtime update approach based on Java that a offers flexible dynamic software updates, b is platform independent, c introduces only minimal performance overhead, and d does not dictate the program architecture. JavAdaptor combines schema changing class replacements by class renaming and caller updates with Java HotSwap using containers and proxies. It runs on top of all major standard Java virtual machines. We evaluate our approach's applicability and performance in non-trivial case studies and compare it with existing dynamic software update approaches. Copyright © 2012 John Wiley & Sons, Ltd.\",\n \"Title: AOP vs Software Evolution: a Score in Favor of the Blueprint\\nYear: 2007\\n\\nAbstract: All software systems are subject to evolution, independently by the developing technique. Aspect oriented software in addition to sep- arate the different concerns during the software development, must be \\\"not fragile\\\" against software evolution. Otherwise, the benefit of disentangling the code will be burred by the extra complication in maintaining the code. Toobtainthisgoal, theaspect-orientedlanguages/toolsmustevolve, they have to be less coupled to the base program. In the last years, a few attempts have been proposed, the Blueprint is our proposal based on behavioral patterns. InthispaperwetesttherobustnessoftheBlueprintaspect-oriented language against software evolution.\",\n \"Title: [a]C#: C# with a customizable code annotation mechanism\\nYear: 2005\\n\\nAbstract: Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The extensible model proposed in both platforms limits annotations to class members. In this paper we describe [a]C#,1 an extension of the C# programming language, that allows programmers to annotate statements or code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. Finally, we discuss how to use [a]C# to annotate programs giving hints on how to parallel a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language.\",\n \"Title: Reflection and Meta-level Architectures: State of the Art and Future Trends\\nYear: 2000\\n\\nAbstract: Previous workshops on reflection both in ECOOP and in OOPSLA have pointed out the growing interest and importance of Reflection and Metalevel Architectures in the fields of programming languages and systems (ECOOP'98, OOPSLA'98), software engineering (OOPSLA'99) and middleware (Middleware 2000). Following these workshops but also the conference Reflection'99 held in Saint-Malo (France), this workshop has provided an opportunity for researchers with a broad range of interests in meta-level architectures and reflective techniques to discuss recent developments in this field. It has also provided a good test-bed for preparing them to submit their works to Reflection'01. The workshop main goal is to encourage people to present works in progress. These works could cover all the spectrum from theory to practice. To ensure creativity, originality, and audience interests, participants have been selected by the workshop organizers on the basis of 5-page position paper. We hope that the workshop will help them to mature their idea and improve the quality of their future publications based on the presented work.\",\n \"Title: Domain-Specific languages in few steps: the neverlang approach\\nYear: 2012\\n\\nAbstract: Often an ad hoc programming language integrating features from different programming languages and paradigms represents the best choice to express a concise and clean solution to a problem. But, developing a programming language is not an easy task and this often discourages from developing your problem-oriented or domain-specific language. To foster DSL development and to favor clean and concise problem-oriented solutions we developed Neverlang The Neverlang framework provides a mechanism to build custom programming languages up from features coming from different languages. The composability and flexibility provided by Neverlang permit to develop a new programming language by simply composing features from previously developed languages and reusing the corresponding support code (parsers, code generators, …). In this work, we explore the Neverlang framework and try out its benefits in a case study that merges functional programming à la Python with coordination for distributed programming as in Linda.\",\n \"Title: Co-evolving application code and design models by exploiting meta-data\\nYear: 2007\\n\\nAbstract: Evolvability and adaptability are intrinsic properties of today's software applications. Unfortunately, the urgency of evolving/adapting a system often drives the developer to directly modify the application code neglecting to update its design models. Even, most of the development environments support the code refactoring without supporting the refactoring of the design information. Refactoring, evolution and in general every change to the code should be reflected into the design models, so that these models consistently represent the application and can be used as documentation in the successive maintenance steps. The code evolution should not evolve only the application code but also its design models. Unfortunately, to co-evolve the application code and its design is a hard job to be carried out automatically, since there is an evident and notorious gap between these two representations. We propose a new approach to code evolution (in particular to code refactoring) that supports the automatic co-evolution of the design models. The approach relies on a set of predefined metadata that the developer should use to annotate the application code and to highlight the refactoring performed on the code. Then, these meta-data are retrieved through reflection and used to automatically and coherently update the application design models.\",\n \"Title: On the Maintainability of Aspect-Oriented Software: A Concern-Oriented Measurement Framework\\nYear: 2008\\n\\nAbstract: Aspect-oriented design needs to be systematically assessed with respect to modularity flaws caused by the realization of driving system concerns, such as tangling, scattering, and excessive concern dependencies. As a result, innovative concern metrics have been defined to support quantitative analyses of concern's properties. However, the vast majority of these measures have not yet being theoretically validated and managed to get accepted in the academic or industrial settings. The core reason for this problem is the fact that they have not been built by using a clearly-defined terminology and criteria. This paper defines a concern-oriented framework that supports the instantiation and comparison of concern measures. The framework subsumes the definition of a core terminology and criteria in order to lay down a rigorous process to foster the definition of meaningful and well-founded concern measures. In order to evaluate the framework generality, we demonstrate the framework instantiation and extension to a number of concern measures suites previously used in empirical studies of aspect-oriented software maintenance.\",\n \"Title: A concern-oriented framework for dynamic measurements.\\nYear: 2015\\n\\nAbstract: Evolving software programs requires that software developers reason quantitatively about the modularity impact of several concerns, which are often scattered over the system. To this respect, concern-oriented software analysis is rising to a dominant position in software development. Hence, measurement techniques play a fundamental role in assessing the concern modularity of a software system. Unfortunately, existing measurements are still fundamentally module-oriented rather than concern-oriented. Moreover, the few available concern-oriented metrics are defined in a non-systematic and shared way and mainly focus on static properties of a concern, even if many properties can only be accurately quantified at run-time. Hence, novel concern-oriented measurements and, in particular, shared and systematic ways to define them are still welcome. This paper poses the basis for a unified framework for concern-driven measurement. The framework provides a basic terminology and criteria for defining novel concern metrics. To evaluate the framework feasibility and effectiveness, we have shown how it can be used to adapt some classic metrics to quantify concerns and in particular to instantiate new dynamic concern metrics from their static counterparts.\",\n \"Title: On the incremental growth and shrinkage of LR goto-graphs\\nYear: 2014\\n\\nAbstract: The LR(0) goto-graph is the basis for the construction of parsers for several interesting grammar classes such as LALR and GLR. Early work has shown that even when a grammar is an extension to another, the goto-graph of the first is not necessarily a subgraph of the second. Some authors presented algorithms to grow and shrink these graphs incrementally, but the formal proof of the existence of a particular relation between a given goto-graph and a grown or shrunk counterpart seems to be still missing in literature as of today. In this paper we use the recursive projection of paths of limited length to prove the existence of one such relation, when the sets of productions are in a subset relation. We also use this relation to present two algorithms (Grow and Shrink) that transform the goto-graph of a given grammar into the goto-graph of an extension or a restriction to that grammar. We implemented these algorithms in a dynamically updatable LALR parser generator called DEXTER (the Dynamically EXTEnsible Recognizer) that we are now shipping with our current implementation of the Neverlang framework for programming language development.\",\n \"Title: Automating variability model inference for component-based language implementations\\nYear: 2014\\n\\nAbstract: Recently, domain-specific language development has become again a topic of interest, as a means to help designing solutions to domain-specific problems. Componentized language frameworks, coupled with variability modeling, have the potential to bring language development to the masses, by simplifying the configuration of a new language from an existing set of reusable components. However, designing variability models for this purpose requires not only a good understanding of these frameworks and the way components interact, but also an adequate familiarity with the problem domain. In this paper we propose an approach to automatically infer a relevant variability model from a collection of already implemented language components, given a structured, but general representation of the domain. We describe techniques to assist users in achieving a better understanding of the relationships between language components, and find out which languages can be derived from them with respect to the given domain.\",\n \"Title: Using models to dynamically refactor runtime code\\nYear: 2014\\n\\nAbstract: Modern software systems that play critical roles in society's infrastructures are often required to change at runtime so that they can continuously provide essential services in the dynamic environments they operate in. Updating open, distributed software systems at runtime is very challenging. Using runtime models as an interface for updating software at runtime can help developers manage the complexity of updating software while it is executing. To support this idea, we developed the FiGA framework that permits developers to update running software through changes made to UML models of the running software. In this paper, we address the following question: can the UML models be used to express any type of code change a developer desires? Specifically, we report our experience on applying Fowler's code refactoring catalog through model refactoring in the FiGA framework. The goal of this work is to show that the set of FiGA change operators is complete by showing that the refactorings at the source code level can be expressed as model changes in the FiGA approach.\",\n \"Title: A fresh look at programming-in-the-large\\nYear: 1998\\n\\nAbstract: Realizing a shift of software engineering towards a component-based approach to software development re- quires the development of higher level programming systems supporting the development of systems from components. This paper presents a novel approach to the design of large software systems where a program-in-the- large describing the system's architecture is executed at run-time to rule over the assembly and dynamic coopera- tion of components. This approach has several advan- tages following from a clean separation of concerns be- tween programming-in-the-small and programming-in- the-large issues in instantiated systems. Based on these considerations, we propose a new ap- proach to programming-i n-the-large which is centred around two main ideas: the program-in-the-large of a system should describe the system's architecture; and it should be executed at run-time as an independent (higher- level) program with respect to the components' pro- grams. We term this approach Dynamic Architectural Programming-in-the-Large (DAPIL). This paper presents this vision. Section 2 provides the rationale for DAPIL by stating the implicit architecture problem underlying current approaches to component-based development. In section 3, we present a sample syntax and semantics for a programming language for DAPIL and in section 4 we sketch the component and system model underlying them. Section 5 discusses how our approach accommo- dates addressing dynamic architectures in a reflective way. Section 6 points out at some benefits of the pro- posed approach and section 7 draws some conclusion and presents future work. 2: The implicit architecture problem\",\n \"Title: Neverlang: A framework for feature-oriented language development\\nYear: 2015\\n\\nAbstract: Reuse in programming language development is an open research problem. Many authors have proposed frameworks for modular language development. These frameworks focus on maximizing code reuse, providing primitives for componentizing language implementations. There is also an open debate on combining feature-orientation with modular language development. Feature-oriented programming is a vision of computer programming in which features can be implemented separately, and then combined to build a variety of software products. However, even though feature-orientation and modular programming are strongly connected, modular language development frameworks are not usually meant primarily for feature-oriented language definition. In this paper we present a model of language development that puts feature implementation at the center, and describe its implementation in the Neverlang framework. The model has been evaluated through several languages implementations: in this paper, a state machine language is used as a means of comparison with other frameworks, and a JavaScript interpreter implementation is used to further illustrate the benefits that our model provides.\",\n \"Title: Using Models to Validate Unanticipated, Fine-Grained Adaptations at Runtime\\nYear: 2016\\n\\nAbstract: An increasing number of modern software systems need to be adapted at runtime while they are still executing. It becomes crucial to validate each adaptation before it is deployed to the running system. Models are used to ease software maintenance and can, therefore, be used to manage dynamic software adaptations. For example, models are used to manage coarse-grained anticipated adaptations for self-adaptive systems. However, the need for both fine-grained and unanticipated adaptations is becoming increasingly common, and their validation is also becoming more crucial. This paper proposes an approach to validate unanticipated, fine-grained adaptations performed on models before the adaptations are deployed into the running system. The proposed approach exploits model execution where model representations of the test suites of a software system are executed. The proposed approach is demonstrated and evaluated within the Fine Grained Adaptation (FiGA) framework.\",\n \"Title: DSL evolution through composition\\nYear: 2010\\n\\nAbstract: The use of domain specific languages (DSL), instead of general purpose languages introduces a number of advantages in software development even if could be problematic to maintain the DSL consistent with the evolution of the domain. Traditionally, to develop a compiler/interpreter from scratch but also to modify an existing compiler to support the novel DSL is a long and difficult task. We have developed Neverlang to simplify and speed up the development and maintenance of DSLs. The framework presented in this article not only allows to develop the syntax and the semantic of a new language from scratch but it is particularly focused on the reusability of the language definition. The interpreters/compilers produced with such a framework are modular and it is easy to add remove or modify their sections. This allows to modify the DSL definition in order to follow the evolution of the underneath domain. In this work, we explore the Neverlang framework and try out the adaptability of its language definition.\",\n \"Title: Engineering sustainability through language\\nYear: 2015\\n\\nAbstract: As our understanding and care for sustainability concerns increases, so does the demand for incorporating these concerns into software. Yet, existing programming language constructs are not well-aligned with concepts of the sustainability domain. This undermines what we term technical sustainability of the software due to (i) increased complexity in programming of such concerns and (ii) continuous code changes to keep up with changes in (environmental, social, legal and other) sustainability-related requirements. In this paper we present a proof-of-concept approach on how technical sustainability support for new and existing concerns can be provided through flexible language-level programming. We propose to incorporate sustainability-related behaviour into programs through micro-languages enabling such behaviour to be updated and/or redefined as and when required.\",\n \"Title: Choosy and picky: configuration of language product lines\\nYear: 2015\\n\\nAbstract: Although most programming languages naturally share several language features, they are typically implemented as a monolithic product. Language features cannot be plugged and unplugged from a language and reused in another language. Some modular approaches to language construction do exist but composing language features requires a deep understanding of its implementation hampering their use. The choose and pick approach from software product lines provides an easy way to compose a language out of a set of language features. However, current approaches to language product lines are not sufficient enough to cope with the complexity and evolution of real world programming languages. In this work, we propose a general light-weight bottom-up approach to automatically extract a feature model from a set of tagged language components. We applied this approach to the Neverlang language development framework and developed the AiDE tool to guide language developers towards a valid language composition. The approach has been evaluated on a decomposed version of Javascript to highlight the benefits of such a language product line.\",\n \"Title: Experience of an International Collaborative Project with First Year Programming Students\\nYear: 2015\\n\\nAbstract: This paper describes an Erasmus Intensive Programme that used international collaboration as a novel pedagogical approach to teaching programming skills to first-year students in a blended learning context using a mixture of virtual environment and intensive teaching. The experience and outcomes of the Programme are evaluated from the viewpoints of the students and instructors and conclusions are drawn on the value and conduct of international student collaborations.\",\n \"Title: Language components for modular DSLs using traits.\\nYear: 2016\\n\\nAbstract: Recent advances in tooling and modern programming languages have progressively brought back the practice of developing domain-specific languages as a means to improve software development. Consequently, the problem of making composition between languages easier by emphasizing code reuse and componentized programming is a topic of increasing interest in research. In fact, it is not uncommon for different languages to share common features, and, because in the same project different DSLs may coexist to model concepts from different problem areas, it is interesting to study ways to develop modular, extensible languages. Earlier work has shown that traits can be used to modularize the semantics of a language implementation; a lot of attention is often spent on embedded DSLs; even when external DSLs are discussed, the main focus is on modularizing the semantics. In this paper we will show a complete trait-based approach to modularize not only the semantics but also the syntax of external DSLs, thereby simplifying extension and therefore evolution of a language implementation. We show the benefits of implementing these techniques using the Scala programming language. HighlightsThe contribution of this work is to synthesize a collection of patterns and techniques that can be used to implement language components, using traits. Separate the syntactic concern from the construction of the abstract representation of the language. Separate the abstract representation of the language from the implementation of its semantics. Modularize the implementation of the semantics in distinct phases; decouple the abstract representation from the semantics of each phase, possibly expressing dependencies between phases. The benefit of representing language concepts through traits is an improved modularization, thereby simplifying code sharing across language implementations. Moreover, since traits in most languages can be written as separate code units, employing them in the modularization of a language make it possible to compile each language component separately and independently from the others, allowing them to be shared as binary assets, that, nevertheless, can be still combined together post-compilation. Scala's trait implementation has been used to demonstrate our contribution.\",\n \"Title: Formal Attributes Traceability in Modular Language Development Frameworks.\\nYear: 2016\\n\\nAbstract: Modularization and component reuse are concepts that can speed up the design and implementation of domain specific languages. Several modular development frameworks have been developed that rely on attributes to share information among components. Unfortunately, modularization also fosters development in isolation and attributes could be undefined or used inconsistently due to a lack of coordination. This work presents 1) a type system that permits to trace attributes and statically validate the composition against attributes lack or misuse and 2) a correct and complete type inference algorithm for this type system. The type system and inference are based on the Neverlang development framework but it is also discussed how it can be used with different frameworks.\",\n \"Title: Model-Based Regression Test Selection for Validating Runtime Adaptation of Software Systems\\nYear: 2016\\n\\nAbstract: An increasing number of modern software systems need to be adapted at runtime without stopping their execution. Runtime adaptations can introduce faults in existing functionality, and thus, regression testing must be conducted after an adaptation is performed but before the adaptation is deployed to the running system. Regression testing must be completed subject to time and resource constraints. Thus, test selection techniques are needed to reduce the cost of regression testing. The FiGA framework provides a complete loop from code to models and back that allows fine-grained model-based adaptation and validation of running Java systems without stopping their execution. In this paper we present a model-based test selection approach for regression testing during the validation activity to be used with the FiGA framework. The evaluation results show that our approach was able to reduce the number of selected test cases, and that the model-level fault detection ability of the selected test cases was never lower than that of the original test cases.\",\n \"Title: Apples and oranges: comparing top-down and bottom-up language product lines.\\nYear: 2016\\n\\nAbstract: Over the past decade language development tools have been significantly improved. This permitted both practitioners and researchers to design a wide variety of domain-specific languages (DSL) and extensions to programming languages. Moreover, multiple researchers have combined different language variants to form families of DSLs as well as programming languages. Unfortunately, current language development tools cannot directly support the development of these families. To overcome this limitation, researchers have recently applied ideas from software product lines (SPL) to create product lines of compilers/interpreters for language families, denoted language product lines (LPL). Similar to SPLs, however, these product lines can be created either using a top-down or a bottom-up approach. Yet, there exist no case study comparing the suitability of both approaches to the development of LPLs, making it unclear how language development tools should evolve. Accordingly, this paper compares both feature modeling approaches by applying them to the development of an LPL for the family of role-based programming languages and discussing their applicability, feasibility and overall suitability for the development of LPLs. Although one might argue that this compares apples and oranges, we believe that this case still provides crucial insights into the requirements, assumptions, and challenges of each approach.\",\n \"Title: Dodging Unsafe Update Points in Java Dynamic Software Updating Systems\\nYear: 2016\\n\\nAbstract: Dynamic Software Updating (DSU) provides mechanisms to update a program without stopping its execution. An indiscriminate update, that does not consider the current state of the computation, potentially undermines the stability of the running application. To automatically determine a safe moment when to update the running system is still an open problem often neglected from the existing DSU systems. This paper proposes a mechanism to support the choice of a safe update point by marking which point can be considered unsafe and therefore dodged during the update. The method is based on decorating the code with some specific meta-data that can be used to find the right moment to do the update. The proposed approach has been implemented as an external component that can be plugged into every DSU system. The approach is demonstrated on the evolution of the HSQLDB system from two distinct versions to their next update.\",\n \"Title: Open Programming Language Interpreters.\\nYear: 2017\\n\\nAbstract: Context: This paper presents the concept of open programming language interpreters and the implementation of a framework-level metaobject protocol (MOP) to support them. Inquiry: We address the problem of dynamic interpreter adaptation to tailor the interpreteru0027s behavior on the task to be solved and to introduce new features to fulfill unforeseen requirements. Many languages provide a MOP that to some degree supports reflection. However, MOPs are typically language-specific, their reflective functionality is often restricted, and the adaptation and application logic are often mixed which hardens the understanding and maintenance of the source code. Our system overcomes these limitations. Approach: We designed and implemented a system to support open programming language interpreters. The prototype implementation is integrated in the Neverlang framework. The system exposes the structure, behavior and the runtime state of any Neverlang-based interpreter with the ability to modify it. Knowledge: Our system provides a complete control over interpreteru0027s structure, behavior and its runtime state. The approach is applicable to every Neverlang-based interpreter. Adaptation code can potentially be reused across different language implementations. Grounding: Having a prototype implementation we focused on feasibility evaluation. The paper shows that our approach well addresses problems commonly found in the research literature. We have a demonstrative video and examples that illustrate our approach on dynamic software adaptation, aspect-oriented programming, debugging and context-aware interpreters. Importance: To our knowledge, our paper presents the first reflective approach targeting a general framework for language development. Our system provides full reflective support for free to any Neverlang-based interpreter. We are not aware of any prior application of open implementations to programming language interpreters in the sense defined in this paper. Rather than substituting other approaches, we believe our system can be used as a complementary technique in situations where other approaches present serious limitations.\",\n \"Title: Context-Aware Software Variability through Adaptable Interpreters.\\nYear: 2017\\n\\nAbstract: A proposed approach moves variability support from the programming language to the language implementation level. This enables contextual variability in any application independently of whether the underlying language supports context-oriented programming. A Neverlang-based prototype implementation illustrates this approach.\",\n \"Title: μ-DSU: A Micro-Language Based Approach to Dynamic Software Updating.\\nYear: 2018\\n\\nAbstract: •This paper presents μ-DSU a linguistic approach to dynamic software updating (DSU).•The μ-DSU framework is implemented on top of Neverlang. μ-DSU exploits Neverlang’s characteristic to permit a dynamic update of the interpreter during its execution.•μ-DSU has the benefit of easing the introduction and the update of nonfunctional concerns in a running application.•μ-DSU update process leaves the application code untouched reducing the complexity of the updating process and fostering adaptation reuse on a broader scale.•Demonstration studies are provided.\",\n \"Title: Modular feature-oriented graphical editor product lines.\\nYear: 2018\\n\\nAbstract: Software Product Lines (SPLs) have a long tradition and aim at reducing development costs by increasing reuse. They have been successfully applied to develop families of languages, ultimately establishing the field of Language Product Lines (LPLs). Currently, LPLs facilitate a family of textual languages by defining an SPL of compilers/interpreters. In contrast, this work aims at supporting families of graphical languages by defining an SPL of graphical editors, whereas each language variant is supported by a corresponding product of a Graphical Editor Product Line (GEPL). Thus far, there exists no modular approach for the development of GEPLs for families of visual languages. To remedy this, this paper introduces a feature-oriented development approach for GEPLs that ensures modularity, maintainability, and extensibility of the resulting product line. To showcase the suitability and applicability of our approach, we developed a modular GEPL for the family of role-based modeling languages, a feature rich family of conceptual modeling languages. Finally, we illustrate its extensibility by adding a complex language feature.\",\n \"Title: AOSD and reflection: benefits and drawbacks to software evolution\\nYear: 2006\\n\\nAbstract: Following last two years' RAM-SE (Reflection, AOP and Meta-Data for Software Evolution) workshop at the ECOOP conference, the RAM-SE 2006 workshop was a successful and popular event. As its name implies, the workshop's focus was on the application of reflective, aspect-oriented and data-mining techniques to the broad field of software evolution. Topics and discussions at the workshop included mechanisms for supporting software evolution, technological limits for software evolution and tools and middleware for software evolution. The workshop's main goal was to bring together researchers working in the field of software evolution with a particular interest in reflection, aspect-oriented programming and meta-data. The workshop was organized as a full day meeting, partly devoted to presentation of submitted position papers and partly devoted to panel discussions about the presented topics and other interesting issues in the field. In this way, the workshop allowed participants to get acquainted with each other's work, and stimulated collaboration. We hope this helped participants in improving their ideas and the quality of their future publications. The workshop's proceedings, including all accepted position papers can be downloaded from the workshop's web site and a post workshop proceeding, including an extension of the accepted paper is published byt the University of Magdeburg. In this report, we first provide a session-by-session overview of the presentations, and then present our opinions about future trends in software evolution.\",\n \"Title: Viewpoint For Maintaining Uml Models Against Application Changes\\nYear: 2006\\n\\nAbstract: The urgency that characterizes many requests for evolution forces the system administrators/developers of directly adapting the system without passing through the adaptation of its design. This creates a gap between the design information and the system it describes. The existing design models provide a static and often outdated snapshot of the system unrespectful of the system changes. Software developers spend a lot of time on evolving the system and then on updating the design information according to the evolution of the system. To this respect, we present an approach to automatically keep the design information (UML diagrams in our case) updated when the system evolves. The UML diagrams are bound to the application and all the changes to it are reflected to the diagrams as well.\",\n \"Title: A Fuzzy Logic Based Approach for Model-Based Regression Test Selection\\nYear: 2017\\n\\nAbstract: Regression testing is performed to verify that previously developed functionality of a software system is not broken when changes are made to the system. Since executing all the existing test cases can be expensive, regression test selection (RTS) approaches are used to select a subset of them, thereby improving the efficiency of regression testing. Model-based RTS approaches select test cases on the basis of changes made to the models of a software system. While these approaches are useful in projects that already use model-driven development methodologies, a key obstacle is that the models are generally created at a high level of abstraction. They lack the information needed to build traceability links between the models and the coverage-related execution traces from the code-level test cases. In this paper, we propose a fuzzy logic based approach named FLiRTS, for UML model-based RTS. FLiRTS automatically refines abstract UML models to generate multiple detailed UML models that permit the identification of the traceability links. The process introduces a degree of uncertainty, which is addressed by applying fuzzy logic based on the refinements to allow the classification of the test cases as retestable according to the probabilistic correctness associated with the used refinement. The potential of using FLiRTS is demonstrated on a simple case study. The results are promising and comparable to those obtained from a model-based approach (MaRTS) that requires detailed design models, and a code-based approach (DejaVu).\",\n \"Title: Supporting inheritance hierarchy changes in model-based regression test selection\\nYear: 2019\\n\\nAbstract: Models can be used to ease and manage the development, evolution, and runtime adaptation of a software system. When models are adapted, the resulting models must be rigorously tested. Apart from adding new test cases, it is also important to perform regression testing to ensure that the evolution or adaptation did not break existing functionality. Since regression testing is performed with limited resources and under time constraints, regression test selection (RTS) techniques are needed to reduce the cost of regression testing. Applying model-level RTS for model-based evolution and adaptation is more convenient than using code-level RTS because the test selection process happens at the same level of abstraction as that of evolution and adaptation. In earlier work, we proposed a model-based RTS approach called MaRTS to be used with a fine-grained model-based adaptation framework that targets applications implemented in Java. MaRTS uses UML models consisting of class and activity diagrams. It classifies test cases as obsolete, reusable, or retestable based on changes made to UML class and activity diagrams of the system being adapted. However, MaRTS did not take into account the changes made to the inheritance hierarchy in the class diagram and the impact of these changes on the selection of test cases. This paper extends MaRTS to support such changes and demonstrates that the extended approach performs as well as or better than code-based RTS approaches in safely selecting regression test cases. While MaRTS can generally be used during any model-driven development or model-based evolution activity, we have developed it in the context of runtime adaptation. We evaluated the extended MaRTS on a set of applications and compared the results with code-based RTS approaches that also support changes to the inheritance hierarchy. The results showed that the extended MaRTS selected all the test cases relevant to the inheritance hierarchy changes and that the fault detection ability of the selected test cases was never lower than that of the baseline test cases. The extended MaRTS achieved comparable results to a graph-walk code-based RTS approach (DejaVu) and showed a higher reduction in the number of selected test cases when compared with a static analysis code-based RTS approach (ChEOPSJ).\",\n \"Title: Concern-oriented language development (COLD): Fostering reuse in language engineering.\\nYear: 2018\\n\\nAbstract: •Present a new language development model that promotes modularity and reusability.•Promote the development of language concern as reusable piece of language that consists of usual language artifacts (e.g., abstract syntax, concrete syntax, semantics) and exhibits three specific interfaces that support (1) variability management, (2) customization to a specific context, and (3) proper usage of the reused artifact.•The approach is supported by a conceptual model which introduces the required concepts to implement COLD.•We also present concrete examples of some language concerns and the current state of their realization with metamodel-based and grammar-based language workbenches.\",\n \"Title: Bridging the model-to-code abstraction gap with fuzzy logic in model-based regression test selection\\nYear: 2022\\n\\nAbstract: Regression test selection (RTS) approaches reduce the cost of regression testing of evolving software systems. Existing RTS approaches based on UML models use behavioral diagrams or a combination of structural and behavioral diagrams. However, in practice, behavioral diagrams are incomplete or not used. In previous work, we proposed a fuzzy logic based RTS approach called FLiRTS that uses UML sequence and activity diagrams. In this work, we introduce FLiRTS 2, which drops the need for behavioral diagrams and relies on system models that only use UML class diagrams, which are the most widely used UML diagrams in practice. FLiRTS 2 addresses the unavailability of behavioral diagrams by classifying test cases using fuzzy logic after analyzing the information commonly provided in class diagrams. We evaluated FLiRTS 2 on UML class diagrams extracted from 3331 revisions of 13 open-source software systems, and compared the results with those of code-based dynamic (Ekstazi) and static (STARTS) RTS approaches. The average test suite reduction using FLiRTS 2 was 82.06%. The average safety violations of FLiRTS 2 with respect to Ekstazi and STARTS were 18.88% and 16.53%, respectively. FLiRTS 2 selected on average about 82% of the test cases that were selected by Ekstazi and STARTS. The average precision violations of FLiRTS 2 with respect to Ekstazi and STARTS were 13.27% and 9.01%, respectively. The average mutation score of the full test suites was 18.90%; the standard deviation of the reduced test suites from the average deviation of the mutation score for each subject was 1.78% for FLiRTS 2, 1.11% for Ekstazi, and 1.43% for STARTS. Our experiment demonstrated that the performance of FLiRTS 2 is close to the state-of-art tools for code-based RTS but requires less information and performs the selection in less time.\",\n \"Title: Towards a recipe for language decomposition: quality assessment of language product lines\\nYear: 2022\\n\\nAbstract: Programming languages are complex systems that are usually implemented as monolithic interpreters and compilers. In recent years, researchers and practitioners gained interest in product line engineering to improve the reusability of language assets and the management of variability-rich systems, introducing the notions of language workbenches and language product lines (LPLs). Nonetheless, language development remains a complex activity and design or implementation flaws can easily waste the efforts of decomposing a language specification into language features. Poorly designed language decompositions result in high inter-dependent components, reducing the variability space of the LPL system and its maintainability. One should detect and fix the design flaws posthaste to prevent these risks while minimizing the development overhead. Therefore, various aspects of the quality of a language decomposition should be quantitatively measurable through adequate metrics. The evaluation, analysis and feedback of these measures should be a primary part of the engineering process of a LPL. In this paper, we present an exploratory study trying to capture these aspects by introducing a design methodology for LPLs; we define the properties of a good language decomposition and adapt a set of metrics from the literature to the framework of language workbenches. Moreover, we leverage the AiDE 2 LPL engineering environment to perform an empirical evaluation of 26 Neverlang-based LPLs based on this design methodology. Our contributions form the foundations of a design methodology for Neverlang-based LPLs. This methodology is comprised of four different elements: i) an engineering process that defines the order in which decisions are made, ii) an integrated development environment for LPL designers and iii) some best practices in the design of well-structured language decomposition when using Neverlang, supported by iv) a variety of LPL metrics that can be used to detect errors in design decisions.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":82,"string":"82"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13378,"string":"13,378"}}},{"rowIdx":13379,"cells":{"question_id":{"kind":"string","value":"Lei Cao"},"question":{"kind":"string","value":"Generate an abstract for the title \"Reward-Based Exploration: Adaptive Control For Deep Reinforcement Learning\" using the following items: Keywords: Exploration, Exploitation, Deep Reinforcement Learning, Reward-based exploration strategy, Softmax action selection."},"answer":{"kind":"string","value":"Aiming at the contradiction between exploration and exploitation in deep reinforcement learning, this paper proposes \"reward-based exploration strategy combined with Softmax action selection\" (RBE-Softmax) as a dynamic exploration strategy to guide the agent to learn. The superiority of the proposed method is that the characteristic of agent's learning process is utilized to adapt exploration parameters online, and the agent is able to select potential optimal action more effectively. The proposed method is evaluated in discrete and continuous control tasks on OpenAI Gym, and the empirical evaluation results show that RBE-Softmax method leads to statistically-significant improvement in the performance of deep reinforcement learning algorithms."},"correct_answer":{"kind":"string","value":"Aiming at the contradiction between exploration and exploitation in deep reinforcement learning, this paper proposes \"reward-based exploration strategy combined with Softmax action selection\" (RBE-Softmax) as a dynamic exploration strategy to guide the agent to learn. The superiority of the proposed method is that the characteristic of agent's learning process is utilized to adapt exploration parameters online, and the agent is able to select potential optimal action more effectively. The proposed method is evaluated in discrete and continuous control tasks on OpenAI Gym, and the empirical evaluation results show that RBE-Softmax method leads to statistically-significant improvement in the performance of deep reinforcement learning algorithms."},"documents":{"kind":"list like","value":["Title: Test-pattern-reduced decoding for turbo product codes with multi-error-correcting eBCH codes\nYear: 2009\n\nAbstract: We present a method to reduce the number of test patterns (TPs) decoded in the Chase-II algorithm for turbo product codes (TPCs) constructed with multi-error-correcting extended Bose-Chaudhuri-Hocquengem (eBCH) codes. We classify TPs into different conditions based on the relationship between syndromes and the number of errors so that TPs with the same codeword are not decoded except the one with the least number of errors. For eBCH with code length of 64, simulation results show that over 50% of TPs need not to be decoded without any performance degradation.","Title: Distributed Source Coding Under Noisy Transmission Environments\nYear: 2007\n\nAbstract: Distributed source coding (DSC) has been attracting more and more research interests recently, particularly for mobile wireless applications. However, most existing DSC schemes assume that the coded information is transmitted error free to the decoder end. In this paper, we report our latest investigations on distributed source coding under noisy transmission environments. It is expected that these investigations provide useful guidelines for practical DSC system design when the transmission is actually not error free. Especially, many current schemes in DSC adopted the channel coding principles to accomplish the source coding tasks. We shall illustrate that the channel coding-based DSC schemes possess some inherent noise combating capability to recover possible channel errors under noisy transmission environments. Specifically, we shall report the investigations of Turbo DSC under various environments: error free, noisy transmission with additional forward error correction (FEC) and noisy transmission without FEC. Our experimental results show that with the same number of bits transmitted through noise channel, the unprotected Turbo DSC outperforms the FEC protected Turbo DSC.","Title: A categorized-registry model for grid resource publication and discovery using software agents\nYear: 2004\n\nAbstract: This paper presents a categorized-registry model for Grid Resource Publication and Discovery(GRPD) using software agents. We use Common Resource Model(CRM) specification to describe manageable resources as Open Grid Services Architecture(OGSA) services. We also adopt two-level registry mechanism to register corresponding resources of a Virtual Organization(VO) in order to obtain high GRPD efficiency. The “Index” node of a VO hosts the general registry. Other specific categorized registries are distributed in the VO. A large-scale Grid system may contain many VOs. “Index” nodes from various VOs connect to each other in Peer-to-Peer(P2P) mode instead of hierarchical mode. Software agent is a powerful high-level tool for modeling a complex software system. It is adopted to implement GRPD efficiently.","Title: A lower bound on greedy embedding in euclidean plane\nYear: 2010\n\nAbstract: Greedy embedding is the key of geometric greedy routing in p2p networks It embeds a graph (the topological structure of the p2p network) in a metric space such that between any source-destination pair, there is a distance decreasing path for message delivery It is known that any graph can be greedily embedded in the hyperbolic plane with using O(logn) bits for each node's coordinates [7] Interestingly, on greedy embedding in the Euclidean plane, existing embedding algorithms result in coordinates with ${\\it \\Omega}(n)$ bits It was recently proved that ${\\it \\Omega}(n)$ is a lower bound of the coordinates' bit length if one uses Cartesian or polar coordinate system and preserves the planar embedding of a planar graph when greedily embedding it in the Euclidean plan [2] In this paper we strengthen this result by further proving that ${\\it \\Omega}(n)$ is still a lower bound even if the graph is allowed to take free embedding in the plane.","Title: Soft Information Relaying for Distributed Turbo Product Codes (SIR-DTPC)\nYear: 2010\n\nAbstract: In this letter, we propose a Distributed Turbo Product Code (DTPC) with soft information relaying over cooperative network using block Extended Bose Chaudhuri Hochquenghem (EBCH) codes as component codes. The source broadcasts extended EBCH coded frames to the destination and to a preassigned relay. After soft-decoding, the received sequences and obtaining the Log-Likelihood Ratio (LLR) values, the relay constructs a product code by arranging the decoded bit sequences in rows and re-encoding them along the columns using a novel soft block encoding technique to obtain soft parity bits with different reliabilities that can be used as soft Incremental Redundancy (IR) that is forwarded to the destination. We compared the simulation results in Additive White Gaussian Noise (AWGN) channel with our previous work for Decode and Forward (DF) DTPC and with noncooperative case. The proposed system shows better Bit Error Rate (BER) performance and less sensitivity to the relay's position.","Title: Defence against Botnets: A Formal Definition and a General Framework\nYear: 2013\n\nAbstract: Botnets have contributed to the significant part of the increasing malicious activities such as Distributed Denial of Service (DDoS), spam, and click fraud. Based on the analysis on the basic and essential characters of botnet, this paper deals with the botnet in two aspects: formal definition and general framework, covering various types of botnets overall. Through the formal definition and the general framework, the essential components of the botnet (i.e. botmaster, Command and Control mechanism, and bots) are described in detail and the features of the vital Command and Control (C&C) mechanism are augmented. The formal definition for botnet, to the best of our knowledge, is first proposed and the general framework, analyzed in some case studies, is not only helpful to interpret the existing botnets in the real world, but also beneficial to the implement of the potential botnets in the future.","Title: A trellis-based technique for blind channel estimation and equalization.\nYear: 2004\n\nAbstract: In this paper, we present a trellis-based blind channel estimation and equalization technique coupling two kinds of adaptive Viterbi algorithms. First, the initial blind channel estimation is accomplished by incorporating the list parallel Viterbi algorithm with the least mean square (LMS) updating approach. In this operation, multiple trellis mappings are preserved simultaneously and ranked in terms of path metrics. Equivalently, multiple channel estimates are maintained and updated once a single symbol is received. Second, the best channel estimate from the above operation will be adopted to set up the whole trellis. The conventional adaptive Viterbi algorithm is then applied to detect the signal and further update the channel estimate alternately. A small delay is introduced for the symbol detection and the decision feedback to smooth the noise impact. An automatic switch between the above two operations is also proposed by exploiting the evolution of path metrics and the linear constraint inherent in the trellis mapping. Simulation has shown an overall excellent performance of the proposed scheme in terms of mean square error (MSE) for channel estimation, robustness to the initial channel guess, computational complexity, and channel equalization.","Title: Scalable distance-based outlier detection over high-volume data streams\nYear: 2014\n\nAbstract: The discovery of distance-based outliers from huge volumes of streaming data is critical for modern applications ranging from credit card fraud detection to moving object monitoring. In this work, we propose the first general framework to handle the three major classes of distance-based outliers in streaming environments, including the traditional distance-threshold based and the nearest-neighbor-based definitions. Our LEAP framework encompasses two general optimization principles applicable across all three outlier types. First, our “minimal probing” principle uses a lightweight probing operation to gather minimal yet sufficient evidence for outlier detection. This principle overturns the state-of-the-art methodology that requires routinely conducting expensive complete neighborhood searches to identify outliers. Second, our “lifespan-aware prioritization” principle leverages the temporal relationships among stream data points to prioritize the processing order among them during the probing process. Guided by these two principles, we design an outlier detection strategy which is proven to be optimal in CPU costs needed to determine the outlier status of any data point during its entire life. Our comprehensive experimental studies, using both synthetic as well as real streaming data, demonstrate that our methods are 3 orders of magnitude faster than state-of-the-art methods for a rich diversity of scenarios tested yet scale to high dimensional streaming data.","Title: Up-Down Links Dualpath Greedy Routing Protocol for Wireless Sensor Networks\nYear: 2012\n\nAbstract: Greedy geographic routing is attractive in wireless sensor networks because of its efficiency and scalability. This paper presents an up-down links dualpath greedy routing (UDLDGR) protocol for wireless sensor networks. The routing protocol not only reserves the features of greedy forwarding algorithm, which is simple, efficient, but also uses different relay nodes to serve as routing nodes for up and down routing paths, makes the energy consumption more balanced. The greatest advantage of UDLDGR is it trades off only small cost for the source node to obtain two different transmission paths information. The multipath strengthens the network reliability, such as load balancing and robustness to failures. Our simulation results show that UDLDGR can improve system lifetime by 20---100% compared to single path approaches.","Title: On the unequal error protection for progressive image transmission.\nYear: 2007\n\nAbstract: In this paper, we consider the unequal error protection (UEP) for progressive image transmission when the coded packet size is fixed. First, we prove that, for the source code with convex rate-distortion (R-D) function and practically used channel codes, the channel code rate for each packet in the optimal rate allocation is nondecreasing indeed. Then, we give an upper bound for the channel code rate of the last packet so that the number of rate allocations in the exhaustive search can be predicted. Further, we propose a heuristic optimization method which has low complexity and obtains performance approaching to the optimal solutions for various channel conditions and transmission rates.","Title: CNP-based Implementation of Service-oriented Workflow Mapping in SHGWMS\nYear: 2008\n\nAbstract: ShanghaiGrid has a complex service-oriented infrastructure. Workflow management is emerging as one of the most important part of it. Because the grid environment is very dynamic and the services are shared among many users, it is impossible to optimize the workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible. In this paper, we propose a method of using Contract Net Protocol(CNP) to implement service-oriented workflow mapping in ShanghaiGrid workflow management system(SHGWMS). Three types of workflow in SHGWMS are denoted as Abstract workflow(AW), Concrete workflow(CW) and Executable workflow(EW). Belief-Desire-Intention(BDI) agent technology in SHGWMS helps the system meet challenges from the grid context. CNP provides a very proper negotiation model for agents. The problem of workflow mapping has been transferred to the problem of multi-agent negotiation with the help of CNP model in SHGWMS. We also propose AW2CW mapping algorithm and CW2EW mapping algorithm to accomplish service-oriented workflow mapping.","Title: Progressive image transmission with genetic algorithm-based optimization and multiple cyclic redundancy check structure\nYear: 2008\n\nAbstract: We consider the transmission of progressive image data over noisy channels when the coded packet size is fixed. The concatenated cyclic redundancy check (CRC) codes and rate-compatible punctured turbo codes are used for error control and detection. In such an application, the distortion-based optimal channel rate allocation for unequal error protection is complex. We first propose a suboptimal genetic algorithm-based method that not only largely reduces the optimization complexity but also obtains performance approaching to the results of a brute force search. In addition, because a large packet size is usually applied when turbo codes are used due to the fact that the coding gain is proportional to the packet size for a given code rate, a single remaining bit error after channel decoding may result in CRC failure and hence the discard of the entire packet Therefore, we further propose a multiple-CRC structure for certain data packets so that more correctly decoded data could be used in source decoding. The promising performance of the proposed scheme has been demonstrated through simulation. (C) 2008 SPIE and IS&T.","Title: Study of objective management appraisal system for the university archives-based on the Grey Clustering Algorithm and association rule\nYear: 2012\n\nAbstract: This paper applies the Grey Clustering Algorithm to the objective management appraisal for university archives, presents the appraisal classification, establishes an evaluation model and gives an example using the Grey Clustering for clear and reliable evaluation. This paper further utilizes the Association Rule and obtains related data from a university's database to find the internal relations between the university and the appraisal result, based on the improved Apriori Algorithm.","Title: Cost-Driven web service selection using genetic algorithm\nYear: 2005\n\nAbstract: Web services composition has been one of the hottest research topics. But with the ever increasing number of functional similar web services being made available on the Internet, there is a need to be able to distinguish them using a set of well-defined Quality of Service (QoS) criteria. The cost is the primary concern of many business processes. In this paper, we propose a new solution using Genetic Algorithm (GA) in cost-driven web service selection. GA is utilized to optimize business process composed of many service agents (SAg). Each SAg corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process with taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using local service selection strategy. The global optimal solution might also be achieved with proper GA parameters.","Title: A workflow services middleware model on ShanghaiGrid\nYear: 2004\n\nAbstract: The ShanghaiGrid is an ongoing grid computing environment (GCE) based on grid service standards and the open grid services architecture. The ShanghaiGrid is a City Grid, which is to provide a general shared information grid platform. Based on this point, a workflow management system is very import especially for user-defined workflow. By using the workflow, users in GCE would compose several grid services as a new service and provide it to others. This enlarges the extensibility and business-originated usage in the GCE. This paper discusses the type of workflow, proposes a model of client-side workflow management system, and the design of several important workflow services. A service discovery process based on workflow is also given.","Title: Robust image transmission based on wavelet tree coding and EREC\nYear: 2001\n\nAbstract: We propose a robust image transmission scheme based on wavelet tree coding and error resilient entropy coding (EREC). After the wavelet decomposition, the coefficients are re-arranged into wavelet trees according to their spatial representation. Each wavelet tree is coded independently so that the scheme is essentially a block-based coding in the spatial domain. Since the self-similarity across subbands is preserved, a high source coding efficiency can be achieved. EREC is then adopted to enhance the error resilience capability of the compressed bitstream. At the receiving end, the automatic re-synchronization of each block is obtained. Furthermore, the bits impacted by the error propagation are more likely located in the low bit-layers so that the resultant degradation is less severe in terms of PSNR. Experimental results show that this proposed scheme can achieve a good error resilient performance","Title: Evaluation of a Novel Load-Balancing Algorithm with Variable Granularity\nYear: 2008\n\nAbstract: In this paper, we propose a Uniform Fine-grain Frame Spreading (UFFS-k, where k is the aggregate factor) algorithm to guarantee packet ordering in load-balanced switches by assigning k cells of the same flow to the fixed k successive intermediate inputs. The UFFS-k algorithm first guarantees packet ordering at input linecards without any computation and communication overhead. As the simulation results demonstrate, UFFS-k offers improved delay performance among existing scheduling algorithms that guarantee packet ordering.","Title: Introduction to an agent-based grid workflow management system\nYear: 2005\n\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. One of the most important grid services is workflow management. Grid workflow applications are also emerging as one of the most interesting application classes for the grid. In this paper, we give an introduction to our agent-based grid workflow management system (AGWMS). AGWMS has a four-layer framework. It bases on the adapter middleware and uses a multi-agent platform to make the system more robust, flexible and intelligent. Artificial Intelligence (AI) planning technology is also utilized to generate the agent plan automatically. Our AGWMS is a novel one.","Title: Joint Source and Channel Coding for Image Transmission over Time Varying Channels\nYear: 2007\n\nAbstract: In this paper, the joint source and channel coding for progressive image transmission over channels with varying SNR is considered. Since the feedback of channel status information generally lags behind the channel variation and the optimization process often causes high computational complexity, it is appropriate to optimally allocate the given bandwidth between the source and channel codes based on the statistics of the channel rather than a specific SNR. In such case, the optimization objective function is no longer in a recursive format and the computational complexity with exhaustive search for the optimal allocation is prohibitive. In this paper, we present a simple yet very effective genetic algorithm (GA) based optimization method so that the near-optimal channel rate allocation can be obtained through crossover and mutation operations over a candidate pool. Simulation shows that this GA-based method always approaches to the optimal results of the brute force search for the considered scenario, but with much lower complexity.","Title: An Adaptive Spatio-Temporal Error Concealment Scheme Based on H.264/AVC.\nYear: 2011\n\nAbstract: An Adaptive Spatio-Temporal Error Concealment (ASTEC) scheme based on H.264/AVC is proposed in the paper to improve the quality of the rebuilt frame in H.264/AVC decoder side. Combining the spatial error concealment method with the temporal one, a new scheme is proposed to conceal an erroneous macro block according to its encoded mode. The temporal error concealment scheme adopts the weighted Boundary Matching Algorithm to recover the erroneous macro block. The spatial error concealment scheme recovers the erroneous macro block by exploiting the directional interpolation which subdivides the macro block according to the number and the direction of edges going through it. Experiments show that the proposed concealment scheme can restrain the diffusion of erroneous macro block and improve the quality of the rebuilt frame subjectively as well as objectively. © 2011 ACADEMY PUBLISHER.","Title: Predicting Content Virality in Social Cascade\nYear: 2013\n\nAbstract: Predicting why and how certain content goes viral is attractive for many applications, such as viral marketing and social network applications, but is still a challenging task today. Existing prediction algorithms focus on predicting the content popularity without considering the timing. Those algorithms are based on information that may be uncommon or computationally expensive. This paper proposes a novel and practical algorithm to predict the virality of content. Instead of predicting the popularity, the algorithm predicts the time for the social cascade size to reach a given viral target. The algorithm is verified by the data from a popular social network - Digg.com and 2 synthesize datasets under different conditions. The results prove that the algorithm can achieve the lower bound with a practical significance for the time to reach the viral target.","Title: A novel product coding and recurrent alternate decoding scheme for image transmission over noisy channels\nYear: 2003\n\nAbstract: In this letter, we present a novel product channel coding and decoding scheme for image transmission over noisy channels. Two convolutional codes with at least one recursive systematic convolutional code are employed to construct the product code. Received data are decoded alternately in two directions. A constrained Viterbi algorithm is proposed to exploit the detection results of cyclic redundancy check codes so that both reduction in error patterns and fast decoding speed are achieved. Experiments with image data coded by the algorithm of set partitioning in hierarchical trees exhibit results better than those currently reported in the literature.","Title: MAP Decoding of Variable Length Codes With Self-Synchronization Strings\nYear: 2007\n\nAbstract: Maximum a posteriori probability (MAP) decoding of Huffman-equivalent variable-length codes (VLCs) has two undesired features. One is the high decoding complexity, and the other is the discrepancy between the objective of MAP decoding and the Levenshtein distance which is commonly used as the performance metric. In this correspondence, improvement over these two issues is targeted through extracting self-synchronization information in VLC coded sequence and incorporating it into MAP decoding. It shown that self-synchronization strings (SSSs) are concatenation of Huffman codewords and can be readily found. Occurrence probabilities of SSSs are then analyzed. By using this self-synchronization information, MAP decoding is split into multiple decoding of short data segments so that both decoding performance improvement and complexity reduction are obtained. Simulation results demonstrate the effectiveness of the proposed method.","Title: On the performance of turbo codes-based hybrid ARQ with segment selective repeat in WCDMA.\nYear: 2006\n\nAbstract: In this paper, a new turbo codes-based hybrid automatic repeat request (TC-HARQ) scheme with segment selective repeat (SSR) is proposed. The main strategy is, upon retransmission, to repeat the data that are most important for the next round of decoding based on the distribution of residual errors after current decoding. The performance in terms of reliability and throughput is analyzed. To adapt to correlated fading channels where an interleaver is always employed before transmission, we further modify the SSR strategy so that data having experienced correlated deep fading are selected for retransmission. Finally, this proposed scheme is applied to the wideband code division multiple access (WCDMA) system under frequency selective fading channels. Simulation results demonstrate that in all single and multiple user cases, SSR-based TC-HARQ leads to significant throughput improvement with similar bit error rate (BER) performance as compared to type-I TC-HARQ.","Title: Peking University at TRECVID 2008: High Level Feature Extraction\nYear: 2008\n\nAbstract: We participated in one task of TRECVID 2008, that is, the high-level feature extraction (HLFE). This paper presents our approaches and results on the HLFE task. We mainly focus on exploring the data imbalance learning in this year, and propose two methods for this problem: (1) adaptive borderline-SMOTE and under-sampling SVM (ABUSVM), and (2) concept category. Our approach can be divided into two phases: feature representation and data imbalance learning. In feature representation phase, four low-level visual features namely color moment grid (CMG), local binary pattern (LBP), Gabor wavelet texture (Gabor), and edge histogram layout (EHL) are combined together in an \"early fusion\" manner. In data imbalance learning phase, ABUSVM and concept category are employed jointly to handle the data imbalance problem. In addition, we also investigate the fusion of 2005 and 2008 training data to improve the performance. The experimental results show our four visual features, ABUSVM, and concept category are effective to improve the performance, while the fusion of 2005 training data decreases the result.","Title: Understanding the pathogenesis of Kawasaki disease by network and pathway analysis.\nYear: 2013\n\nAbstract: Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF-kappa B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.","Title: Multi-User Cooperative Communications with Relay-Coding for Uplink IMT-Advanced 4G Systems\nYear: 2009\n\nAbstract: Adoption of relay stations has been commonly accepted as a key technique for future IMT-advanced 4G systems to improve the link performance. While study in relay systems is often carried out for individual users independently, in this paper, we present a design termed as relay-based multi-user cooperative communication specifically for the uplink of 4G systems. In this system, data streams from multiple users are coded at the relay with an invertible matrix in finite field. These coded data, with information of one user being spread into other data streams, are forwarded by the RS to the base station (BS). The relayed data received at the BS will work together with those received through the direct links between mobile stations (MS) and BS to implement a cooperative process. This is carried out using a turbo decoding process that alternates the decoding between a multi-user decoder and a number of single-user decoders. It is shown through the simulations that the decoding converges within two or three iterations, yet indeed provides significant gains compared with a reference relay system where each user is processed individually.","Title: Uep For Progressive Image Transmission With Ga-Based Optimization\nYear: 2007\n\nAbstract: In this paper, we consider the transmission of progressive image data over noisy channels with the protection of rate-compatible punctured Turbo codes (RCPT) concatenated with multiple cyclic redundancy check (CRC) codes. To optimally allocate the given bandwidth resource for unequal error protection (UEP), a genetic algorithm (GA) based method is proposed to reduce the optimization complexity. In addition, a structure of multiple CRC blocks is employed in some data packets so that more correctly decoded data could be used in decoding. Simulation has demonstrated promising results of the proposed scheme.","Title: Transmit Antenna Selection Strategy in Amplify-and-Forward MIMO Relaying\nYear: 2009\n\nAbstract: We compare the outage performance by applying transmit antenna selection strategies to amplify-and-forward protocol in the MIMO relaying scenario. Although antenna selection is a suboptimal form of beamforming, it enjoys the advantages of tractable optimization and low feedback overhead. Specifically, by combining transmit antenna selection strategies with amplify-and-forward protocol, we propose two suboptimal strategies, TAS-SD&RD and TAS-SR&RD, and compare their performance with the optimal strategy, TAS-Optimal. By observation of simulation, the suboptimal strategy TAS-SD&RD can achieve the full diversity order with only a small performance loss compared with the optimal strategy TAS-Optimal in some antenna configuration scenarios.","Title: Vegetation Coverage Change Trend in Inner Mongolia of China during 1998-2008.\nYear: 2011\n\nAbstract: Vegetation is sensitive to reflect the change of ecological environment, so it is significant to study the vegetation dynamics for ecological environment protection and ecological early warning. Based on the time series of the SPOT/VEGETATION NDVI dataset, this paper has obtained the spatial distribution of NDVI in Inner Mongolia (IM), analyzed the characteristics of NDVI change trend in the period of 1998-2008 by Maximum Value Composites (MVC) and Mann-Kendall test. The main findings are as follows: (1) NDVI time series in most regions of IM has tendency in the recent 10 years. (2) The significant increased areas of vegetation cover are mostly distributed in the area of severe desertification, and the significant decreased areas of vegetation cover are mainly located in the typical steppes.","Title: Defect detection of IC wafer based on two-dimension wavelet transform\nYear: 2010\n\nAbstract: Defect detection of integrated circuit (IC) wafer based on two-dimension wavelet transform (2-D DWT) is presented in this paper. By utilizing the characteristics many of the same chips in a wafer, three images with defects located in the same position and different chips are obtained. The defect images contain the standard image without any defects. 2-D DWT presented in the paper can extract the standard image from the three defect images. The algorithm complexity of the method is close to that of 2-D DWT. After obtaining the standard image, the speed and accuracy of defects detection can be greatly enhanced using the detection method presented in the paper. Using the image gray-scale matching technology, impact of illumination on IC defect detection is solved. Experiments demonstrate that 2-D DWT is fast and accurate to defects detection in an IC image, and the method has high robustness for illumination.","Title: Error Resilient Multiple Description Coding Based On Wavelet Tree Coding And Erec For Wireless Networks\nYear: 2005\n\nAbstract: In this paper, we propose an integrated error resilient MDC scheme for wireless networks with both packet loss and random bit errors. Two descriptions are first generated independently by using index assignment MDSQ. For each description, multiple bit streams are then generated based on wavelet trees along the spatial orientations. The spatial-orientation trees in the wavelet domain are individually encoded using SPIHT Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt EREC to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bilstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients.","Title: Turbo codes-based image transmission for channels with multiple types of distortion.\nYear: 2008\n\nAbstract: Product codes are generally used for progressive image transmission when random errors and packet loss (or burst errors) co-exist. However, the optimal rate allocation considering both component codes gives rise to high-optimization complexity. In addition, the decoding performance may be degraded quickly when the channel varies beyond the design point. In this paper, we propose a new unequal error protection (UEP) scheme for progressive image transmission by using rate-compatible punctured Turbo codes (RCPT) and cyclic redundancy check (CRC) codes only. By sophisticatedly interleaving each coded frame, the packet loss can be converted into randomly punctured bits in a Turbo code. Therefore, error control in noisy channels with different types of errors is equivalent to dealing with random bit errors only, with reduced turbo code rates. A genetic algorithm-based method is presented to further reduce the optimization complexity. This proposed method not only gives a better performance than product codes in given channel conditions but is also more robust to the channel variation. Finally, to break down the error floor of turbo decoding, we further extend the above RCPT/CRC protection to a product code scheme by adding a Reed-Solomon (RS) code across the frames. The associated rate allocation is discussed and further improvement is demonstrated.","Title: A Real-Time Transaction Approach for Grid Services: A Model and Algorithms\nYear: 2004\n\nAbstract: Because transactions in Grid applications often have deadlines, effectively processing real-time transactions in Grid services presents a challenging task. Although real-time transaction techniques have been well studied in databases, they can not be directly applied to the Grid applications due to the characteristics of Grid services. In this paper 3, we propose an effective model and corresponding coordination algorithms to handle real-time transactions for Grid services. The model can intelligently discover required Grid services to process specified subtransactions at runtime, and invoke the algorithms to coordinate these services to satisfy the transactional and real-time requirements, without users involvement in the complex process. We use a Petri net to validate the model and algorithms.","Title: A mobile robot prototype for inspection of overhead bundled conductors\nYear: 2013\n\nAbstract: A new mobile robot prototype for inspection of overhead bundled conductors is proposed. The mobile platform is composed of 4 arms. And there is a motorized rubber wheel on the end of each arm. When the robot runs on a transmission line (eg. 500kv, 4-bundle conductors), its wheels use the lower 2 conductors as a support. Two wheels ride on the left lower line, and the others ride on the right one. Along the direction of the lines, the 4 wheels are arranged by a sequence of 1 front wheel, 2 middle wheels and 1 rear wheel. It could roll over some obstacles (compression splices, vibration dampers, etc). Each arm has 2 degrees of freedom, therefore it could clear other types of obstacles (spacers, suspension clamps, etc).","Title: An Efficient Stopping Criterion for Turbo Product Codes\nYear: 2007\n\nAbstract: In this letter, a stopping criterion using the error- detecting capability of linear block codes is proposed for the decoding of turbo product codes. The iterative decoding is stopped when the outputs from the Chase decoder are valid codewords for all rows and columns simultaneously. Simulation shows that the proposed method can reduce about one and half iterations compared with an existing stoppi...","Title: Asymptotic Performance of Two-Hop Amplify-and-Forward MIMO Relaying with Transmit Antenna Selection\nYear: 2010\n\nAbstract: The asymptotic performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relay network over Rayleigh-fading channels is analyzed. Assuming that the source and destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form statistics of received signal-to-noise ratio (SNR) around original, and present the asymptotic average symbol error rate (SER). By analyzing the high SNR performance, we show that the diversity order, min {NS NR, NR ND} can be achieved for the transmission. The optimal relay selection problem, selecting the relay that minimizes the average SER, is also analyzed which shows that the position of the selected optimal relay depends on the number of antenna of source, relay, and destination. Numerical results that confirm our analysis are also presented in the paper.","Title: ECBRP: An Efficient Cluster-Based Routing Protocol for Real-Time Multimedia Streaming in MANETs\nYear: 2011\n\nAbstract: The dynamic characteristics of wireless networks and stringent QoS requirements of multimedia applications identify significant challenges for providing QoS guarantees for real-time multimedia streaming in such wireless environment. QoS routing protocols can decisively contribute to the QoS provision of network systems. This paper proposes an efficient cluster-based routing protocol (ECBRP) for real-time multimedia streaming in mobile ad hoc networks. First, to improve the stability of clusterheads, we introduce a new algorithm of cluster formation, in consideration of the node mobility and connectivity. Second, a link-broken detection mechanism is designed, which is able to distinguish whether packet loss is due to mobility or congestion, and to make proper reaction. This mechanism contributes to reduce route overhead, and to increase the decodable ratio of video frame at the application layer as well. Third, the routing protocol is enhanced via an adaptive packet salvage strategy, in order to alleviate the congestion in consideration of the characteristics of multimedia traffic. Our simulation experiment results demonstrate that the ECBRP leads to more stable cluster formation than the CBRP, and 80% decreases in the frequency of clusterhead changes against CBRP. As a result, the quality of real-time multimedia streaming is improved significantly, in terms of decodable frame ratio, delay and delay jitter, etc.","Title: Uplink Power Control For An Sc-Fdma Mobile Cellular System\nYear: 2008\n\nAbstract: The uplink power control is essentially important to the link performance and the system stability. By analyzing the SC-FDMA system's interference character, we view the SC-FDMA system as a modified OFDMA system with multi-channel model, and accordingly propose a power control scheme composed of intra-cell and inter-cell power control based on the multi-channel model. Especially the Inter-cell power control based on the interference overload with the form of frequency dependent and event triggered, along with the intra-cell power control, can achieve the target IoT in NodeBs and ensure its stability. This conclusion is achieved by our multi-cell simulation implemented with this power control scheme.","Title: Joint source and channel decoding with symbol re-alignment\nYear: 2006\n\nAbstract: The maximum a-posteriori probability (MAP) decoding of Huffman variable-length codes (VLCs) has been widely used in the joint source and channel decoding. This method exploits both source memory information and channel status information, but does not consider the symbol re-alignment as the conventional Huffman decoding does. In this letter, we show that self-synchronization strings (SSSs) of VLCs can be readily found and used with the MAP decoding. As a result, the performance of symbol error rate based on Levenshtein distance can be improved, with reduced decoding complexity.","Title: Asymptotic performance of amplify-and-forward MIMO relaying with transmit antenna selection.\nYear: 2010\n\nAbstract: This paper proposes two schemes, TAS-SD&RD and TAS-SR&RD, in which transmit antenna selection (TAS) strategies are combined\n with amplify-and-forward (AF) protocol in MIMO relaying scenario considering the destination has only limited channel state\n information (CSI) of the source-to-relay channel, and analyzes asymptotic performance of the two schemes. The source, destination,\n and relay are equipped with multiple antennas, denoted by N\n S, N\n D, and N\n R, respectively. Specifically, the paper derives the asymptotic outage probability and symbol error rate (SER) of the proposed\n schemes in the cooperative AF MIMO relaying scenario. These analyses in high SNR regime lead to the conclusion that TAS-SD&RD\n and TAS-SR&RD can achieve full diversity order, N\n S\n N\n D + NR min {N\n S,N\n D}, in some antenna configurations of the cooperative scenario. Numerical results that confirm our analyses are also presented\n in the paper.","Title: Distributed power allocation for sink-centric clusters in multiple sink wireless sensor networks.\nYear: 2010\n\nAbstract: Due to the battery resource constraints, saving energy is a critical issue in wireless sensor networks, particularly in large sensor networks. One possible solution is to deploy multiple sink nodes simultaneously. Another possible solution is to employ an adaptive clustering hierarchy routing scheme. In this paper, we propose a multiple sink cluster wireless sensor networks scheme which combines the two solutions, and propose an efficient transmission power control scheme for a sink-centric cluster routing protocol in multiple sink wireless sensor networks, denoted as MSCWSNs-PC. It is a distributed, scalable, self-organizing, adaptive system, and the sensor nodes do not require knowledge of the global network and their location. All sinks effectively work out a representative view of a monitored region, after which power control is employed to optimize network topology. The simulations demonstrate the advantages of our new protocol.","Title: Content-based multiple bitstream image transmission over noisy channels.\nYear: 2002\n\nAbstract: In this paper, we propose a novel combined source and channel coding scheme for image transmission over noisy channels. The main feature of the proposed scheme is a systematic decomposition of image sources so that unequal error protection can be applied according to not only bit error sensitivity but also visual content importance. The wavelet transform is adopted to hierarchically decompose the image. The association between the wavelet coefficients and what they represent spatially in the original image is fully exploited so that wavelet blocks are classified based on their corresponding image content. The classification produces wavelet blocks in each class with similar content and statistics, therefore enables high performance source compression using the set partitioning in hierarchical trees (SPIHT) algorithm. To combat the channel noise, an unequal error protection strategy with rate-compatible punctured convolutional/cyclic redundancy check (RCPC/CRC) codes is implemented based on the bit contribution to both peak signal-to-noise ratio (PSNR) and visual quality. At the receiving end, a postprocessing method making use of the SPIHT decoding structure and the classification map is developed to restore the degradation due to the residual error after channel decoding. Experimental results show that the proposed scheme is indeed able to provide protection both for the bits that are more sensitive to errors and for the more important visual content under a noisy transmission environment. In particular, the reconstructed images illustrate consistently better visual quality than using the single-bitstream-based schemes.","Title: Tightened upper bounds for distributed Alamouti's code with a non-regenerative relay\nYear: 2012\n\nAbstract: In this paper, we consider a cooperative system with distributed Alamouti's code that includes a source, a non-regenerative relay and a destination. The relay uses the amplify-and-forward protocol and all links experience independent Rayleigh fading. First, we present a novel approximation method in the series expansion for the error function. Then, we derive, based on the conditional expectation method, an upper bound of the BER performance in a summation of number of easily calculated components. This bound exhibits the even approximation errors for all SNR range and approaches to the exact system performance when the number of components increases. The upper bound is validated with simulation results and it is more accurate and flexible compared with other approximation methods.","Title: Bipartite Graph Based Entity Ranking for Related Entity Finding\nYear: 2011\n\nAbstract: Related entity finding (REF) is a promising application, which aims to return a list of related entities given a query that describes the source entity, the specific type of target entities, and the relation between the source entity and target entities. One typical entity ranking strategy is to rank the candidate entities based on the co-occurrence between the candidate entities and the given query. However, such a strategy is inadequate to rank entities properly especially for those related but unpopular entities. In this paper, we propose a bipartite graph based entity ranking method, which leverage the Co-List relationship between candidate entities (i.e., entities co-occurring in the same structured/unstructured lists) to help improve the entity ranking. Specifically, we first estimate the initial relevance scores for the candidate entities based on a generative probabilistic model. We then construct a bipartite graph based on Co-List relation between candidate entities, and apply an iterative refinement process analogous to heat diffusion on the graph to propagate the relevance scores over entities. Finally the candidate entities are ranked according to their refined scores. We further develop an optimization framework for the iterative refinement process in our ranking method. Experimental results on the data collection from the TREC 2010 Entity Track show the effectiveness of our proposed method.","Title: Robust image transmission based on wavelet tree coding, error resilient entropy coding, and error concealment\nYear: 2004\n\nAbstract: A scheme with three key components including wavelet tree coding, error resilient entropy coding (EREC), and error concealment is proposed for robust image coding and transmission over noisy channels. First, we individually encode the spatial-orientation trees in the wavelet domain using the algorithm of set partitioning in hierarchical trees (SPIHT). Error propagation is thus limited because multiple independent bit streams are generated. Meanwhile, a high source coding efficiency is also preserved because the self-similarity property in each wavelet tree remains intact. Next, we use EREC to reorganize these variable-length bit streams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bit stream can be automatically obtained at the receiver Finally, to alleviate the possible catastrophic image degradation that may result from errors in the beginning of the bit streams, we propose an error concealment technique to constrain the EREC decoding as well as to postprocess the decoded wavelet coefficients. As a result of the error concealment, the EREC decoding complexity is reduced and the reconstructed image quality is significantly improved. Experimental results demonstrate an excellent error resilient performance of the proposed scheme. (C) 2004 SPIE and IST.","Title: On Succinctness of Geometric Greedy Routing in Euclidean Plane\nYear: 2009\n\nAbstract: Geometric greedy routing uses (virtual) geographic point locations as addresses for the purposes of routing, while routing decisions are made by each node individually based only on local information. It requires that the network topology is greedily embedded in a metric space through assigning virtual coordinates to the nodes in the network. Recent research pointed out that such scheme is significantly more efficient than other traditional routing schemes only if the virtual coordinates are succinctly represented (i.e., using O(poly(log n)) bits per coordinate) in the greedy embedding, an issue that has been overlooked for a long time. In this paper we prove that such succinctness is not achievable in Euclidean plane, assuming that Cartesian or polar coordinate system is used, the network topology is a planar graph, and the planar embedding is preserved during the process of greedy embedding. Indeed, we provide a counter example to show that in this situation, some coordinates must take ¿(n) bits to represent.","Title: Product Code and Recurrent Alternative Decoding for Wireless Image Transmission\nYear: 2000\n\nAbstract: We present a novel channel-coding scheme for image transmission over wireless channels. A key component is the application of product code to the compressed source using recursive systematic code (RSC) and classical convolutional code to combat both random and burst channel errors. Our innovation is the development of recurrent alternative decoding for such product code that leads to high performance transmission. The compressed image data are first arranged into an array of bitstreams so that this array can be coded with convolutional codes and RSC in horizontal and vertical directions respectively. At the receiving end, the data will be alternatively decoded along the two directions. In each iteration, any correctly decoded data in one direction will be used to constrain the decoding in the other direction. This is implemented by using a constrained Viterbi algorithm in which the survival paths are forced to pass through the positions where the bits have already been correctly decoded. With such constraint, the recurrent decoding often converges quickly. Experimental results show that the proposed scheme is able to achieve high performance transmission of compressed image data over severely impaired channels.","Title: An Efficient Decoder for Turbo Product Codes with Multi-Error Correcting Codes\nYear: 2007\n\nAbstract: In this paper, Chase decoding algorithm for turbo product codes (TPCs) built with multi-error-correcting codes is investigated. A method is proposed to reduce the decoding of test patterns (TPs) as well as the calculation of syndromes and metrics. In the beginning, syndromes and metrics of the first half of TPs are calculated recursively. After decoding of one TP, according to the error bit positions, other TPs that will have the same decoded codeword are identified and rejected from decoding. In the mean time, if these TPs fall into the range of second half of TPs, their syndromes and metrics need not to be calculated either. Simulations results for TPCs built with eBCH(64,51,6,2) or eBCH(64,45,8,3) are presented to demonstrate the efficiency of the proposed method. Moreover, this method that reduces the inherent redundancy in Chase decoding does not cause any degradation in coding gain.","Title: Scene Adaptive Multiple Coding Scheme For Robust Image Transmission\nYear: 2000\n\nAbstract: In this paper, we propose a combined source and channel coding scheme for image transmission over noisy channels. The key component is extracting and preserving the scene information and incorporating it with unequal error protection to combat the channel errors. After hierarchical wavelet decomposition of the image, wavelet coefficients with parent-child relationship are grouped into wavelet blocks and classified according to corresponding scenes in the original image. For each class, spatial neighborhood coefficients in the high frequency subbands are constrained so that the spatially isolated coefficients are removed and clustered coefficients are retained at the same time. All the wavelet blocks in the same class are grouped together and coded using SPIHT algorithm. High source coding efficiency is preserved even though multiple source coded bitstreams are generated since the wavelet tree structure is untact. In order to combat the channel errors, unequal error protection strategy implemented by RCPC/CRC channel coding is designed based on the bit contribution to both PSNR and human visual sensitivity. Finally, a postprocessing method is developed at the receiving end to restore the degradation due to the residual error after channel decoding. Experimental results show that the proposed scheme is indeed able to provide protection for more important bits and more important visual content under noisy transmission environment. In particular, the reconstructed images illustrate consistently better visual quality.","Title: A Relay-Coding Matrix for Multi-User Cooperative Communications\nYear: 2011\n\nAbstract: In this paper, we consider a scenario that multiple users transmit data to a common destination node with the help of one relay station. We present one coding matrix that is invertible in the finite field and has maximum information spreading. We analyze the performance based on the input-out weight enumerate function (IOWEF) of the relay coding matrix and show a close match with the results of log-likelihood ratio decoding. The method gives a way to readily determine when relay coding is preferred. Further, since data from each user is generally coded with channel codes, using relay coding also enables turbo decoding that alternates between a multi-user relay decoder and single-user decoders at the destination. We show via simulations that the turbo decoding converges within only two or three iterations, yet indeed provides significant gains compared with a reference relay system without multi-user cooperation.","Title: Method of Using BDI Agents to Implement Service-oriented Workflow Mapping in AGWMS\nYear: 2006\n\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is also emerging as one of the most important grid services. Web service composition has been one of the hottest research topics. Grid environment is very dynamic, and the services are shared among many users, it is impossible to optimize the workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible. In this paper, we propose a method of using BDI agents to implement service-oriented workflow mapping in our agent-based grid workflow management system (AGWMS), which helps grid users streamline, manage and monitor their routinely problem solving processes without having to know any details of the underlying complex structure and dynamic state of VOs. BDI agent technology helps the system meet challenges from the grid context. Three types of workflow in AGWMS are denoted as abstract workflow (AW), concrete workflow (CW) and executable workflow (EW). We also propose AW2CW mapping algorithm and CW2EW mapping algorithm to implement service-oriented workflow mapping. Utilization of three workflow types further liberates model designers from sophisticated system details. It also increases the reusability of domain-specific models and improves the fault tolerance of the system","Title: Method of using BDI agents to implement service-oriented workflow mapping in AGWMS\nYear: 2008\n\nAbstract: Workflow management is one of the most important parts of ShanghaiGrid, which has a complex service-oriented infrastructure. Because grid environment is very dynamic and services in it are shared among many users, it is impossible to optimise grid workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible, which is the main objective of grid workflow mapping. In this paper, three types of workflow are denoted as abstract workflow (AW), concrete workflow (CW) and executable workflow (EW). We propose a method of using Belief-desire-intention (BDI) agents to implement service-oriented workflow mapping in the agent-based grid workflow management system (AGWMS) of ShanghaiGrid. BDI agent technology helps the system meet challenges from the grid context. Contract net protocol (CNP) provides a very proper negotiation model for these agents. The problem of workflow mapping has been transferred to the problem of multi-agent negotiation with the help of CNP model in AGWMS. AW2CW and CW2EW mapping algorithms are also given to accomplish service-oriented workflow mapping.","Title: Wheelchair Control Based on Multimodal Brain-Computer Interfaces.\nYear: 2013\n\nAbstract: Electroencephalogram (EEG) based brain-computer interfaces (BCIs) for wheelchair control have great value for those with devastating neuromuscular disorders. Although there have been many attempts to implement EEG-based wheelchair control systems by P300, steady state visual evoked potential (SSVEP), and motor imagery (MI) related event-related desynchronization/ synchronization (ERD/ERS), the number of simultaneous control commands in those BCI systems is strictly limited, and those BCI control do not work for a non-negligible portion of users due to the problem of BCI Illiteracy. In this paper, we develop a multimodal BCI based wheelchair control system, the user could employ subject-optimized mental strategies to produce multiple commands to control the wheelchair, which include ERD/ERS, SSVEP, and simultaneous ERD/ERS and SSVEP. It could not only help address \"BCI illiteracy\", but also provide simultaneous control commands for complex control. Experiment results demonstrate the proposed system is effective and flexible in practical application. © Springer-Verlag 2013.","Title: Robust multiple description image coding over wireless networks based on wavelet tree coding, error resilient entropy coding, and error concealment\nYear: 2008\n\nAbstract: In this paper, we propose an integrated robust multiple description coding (MDC) scheme for compressed still images over error-prone channels with both packet loss and random bit errors. Multiple descriptions are first generated independently by using multiple description scalar quantizer (MDSQ). To achieve an excellent error resilient capability for each description, multiple bitstreams are then generated based on wavelet trees along the spatial orientations. The spatial orientation trees in the wavelet domain are individually encoded using SPIHT. Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt error resilient entropy coding (EREC) to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bitstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients. With analysis and experimental results, we have demonstrated how each of these components has contributed to the overall robustness of the proposed transmission of compressed images over wireless channels.","Title: Performance analysis of two-hop amplify-and-forward MIMO relaying with transmit antenna selection\nYear: 2010\n\nAbstract: The performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relaying network over Rayleigh-fading channels is analyzed. Assuming that the source, destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form cumulative distribution function (CDF) of received signal-to-noise ratio (SNR), and based on the CDF, we then present outage probability and exact symbol error rate (SER) for the AF MIMO relay channel with TAS. Numerical results that confirm our analysis are also presented in the paper.","Title: A Trust Evaluation Method for Supplier Selection\nYear: 2013\n\nAbstract: Trust and reputation systems play important roles in supplier selection, a topic that has been widely investigated from a business and operation point of view. However, we still lack of effective studies on supplier selection with security as the optimal target, which is a very important factor for Information and Communication Technology (ICT) systems. In response, this paper outlines a method that enables people to evaluate the relative and objective trustworthiness of the alternative suppliers. Our analysis is based solely on the original data of the vulnerabilities publicly available from OSVDB and NVD, which are impossible to tamper with. They are then interpreted by an approach that combines the Analytic Hierarchy Process (AHP) and objective analysis that enables the inference of relative trust valuations based on different evaluation indexes. A case study of five well known vendors is demonstrated with qualitative comparison based on visualization of data.","Title: ICTNET at Entity Track TREC 2010.\nYear: 2010\n\nAbstract: This paper gives an overview of our work for related entity finding which is proposed in TREC 2010 Entity Track. The goal of the Entity Track is to find the entities relevant to a given query from the web corpus. In this paper, we propose a bipartite graph reinforcement model for entity ranking. As is well known, the entities on the web are embedded not only in the natural language text, but also in the tables and lists. Given a query, both the candidate entities and relevant tables/lists are extracted from web documents. Then the candidate entities extracted from unstructured text are ranked based on a probabilistic model. But the result contains a lot of noise. If some candidate entities are in a relevant table/list, they are more relevant to the given query. And Vice versa, if a table/list contains several candidate entities, it is also more relevant to the query. Based on the above intuition, we construct a bipartite graph and then perform a reinforcement algorithm to re-rank the candidate entities.","Title: ICTNET at Entity ELC TREC 2011.\nYear: 2011\n\nAbstract: null","Title: Capture the Flag: A Multiplayer Online Game for Phone Users\nYear: 2005\n\nAbstract: This paper explores the concept of using smart phones to facilitate pervasive mixed reality, locationbased, physical and social gaming. The interaction and communication between the virtual and physical worlds are explored and studied using a mixed reality version of the capture-the-flag game. In this game, players from two different paradigms, virtual and real, compete and collaborate in a social gaming environment using mobile devices and network system.","Title: A novel product coding and decoding scheme for wireless image transmission\nYear: 2000\n\nAbstract: This paper presents a novel generic channel coding scheme for image transmission over wireless channels. The product code is constructed using one classical convolutional code in one direction and one recursive systematic code (RSC) in the other direction. At the receiving end, the data are alternatively decoded along the two directions. In each iteration, any correctly decoded data in one direction will be used to constrain the decoding along the other direction. The constrained Viterbi decoding algorithm is designed in such a way that the survival paths are forced to pass through the positions where the bits have already been correctly decoded. With such a constraint, we achieve a reduction of candidate paths for the maximum likelihood (ML) decoding as well as a speed up of convergence. Experimental results show that the proposed scheme is able to outperform all existing schemes under some random and bursty error channel conditions.","Title: Optimization for image transmission over varying channel with MCMC.\nYear: 2012\n\nAbstract: Existing work in media transmission generally assumes that the channel condition is stationary. However, communication channels are often varying with time in practice. Adaptive design needs frequent feedback for channel updates, which is often impractical due to the complexity and delay. In this article, we design the unequal error protection for image transmission over noisy varying channels based on their distribution functions. Since the channel effect must be marginalized in order to find the appropriate rate allocation, the optimization problem is very complex. We propose to solve this problem using the Markov Chain Monte Carlo (MCMC) method. The cost function is first mapped into a multi-variable probability distribution. Then, with the “detailed balance”, MCMC is designed to generate samples from the mapped stationary probability distribution so that the optimal solution is the one that gives the lowest data distortion. We also show that the rate allocation design considering the channel probability function works better than the design considering the mean value of the channel.","Title: Genetic algorithm utilized in cost-reduction driven web service selection\nYear: 2005\n\nAbstract: A single web service is most likely inadequate to serve the customers’ business needs; it takes a selection of various web services composed together to form a business process. The cost is the primary concern of many business processes. In this paper, we propose a new solution using Genetic Algorithm (GA) in cost-reduction driven web service selection. GA is utilized to optimize business process composed of many service agents (SAg), each of which corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process with taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using local service selection strategy.","Title: Automatic geographic web service chaining based-on improved and/or graph\nYear: 2013\n\nAbstract: Nowadays, more and more geospatial applications are provided by geographic web service chaining. Because of large quantities of geo-services and user's personality requirement, it needs to consider both functional and quality of service (QoS) capabilities in geo-service chaining. In this paper, we use geospatial web service dependency graph (GWSDG) to represent the dependencies between services and input/output data, then use BGWSCAOG algorithm to generate GWSDG according to use's request automatically. Finally, we use FOGWSC algorithm to find the GWSC with the global optimal QoS. The implementation of a prototype system and the experimental results show that our approach is not only elegant but also efficient.","Title: Iterative decoding for the concatenated system of VLC and STTC in presence of channel estimation errors\nYear: 2007\n\nAbstract: For wireless communications with limited bandwidth and fading channels, both source coding and MIMO techniqueare generally desired. In this paper, we consider the receiver design for a concatenated system with reversible variable length code (RVLC) and space time trellis code (STTC). The maximum a posteriori probability (MAP) decoding algorithm is adapted for both component decoders considering the facts that information are in both bit and symbol domains; systematic information are inseparable and the trellis structure of RVLC is non-symmetric. Conversion from the extrinsic information to the a priori information is also designed based on the modulation mode and mapping method. As a result, the decoding results of each component decoder can be utilized by the other component decoder iteratively so as to improve the overall decoding performance. The designed receiver is then tested for both quasi-static at and rapid fading channels when channel information is known to the receiver either perfectly or non-perfectly, which has shown significant improvement over the traditional receiver without iterative decoding.","Title: Performance Bounds On Turbo Coded Hybrid Arq\nYear: 2007\n\nAbstract: In this paper, based on the transfer function bounding techniques for turbo codes, we propose performance bounds on turbo coded hybrid automatic repeat request (TC-HARQ) under additive white Gaussian noise (AWGN) channel. The bounds for both Type-I TC-HARQ and segment selective repeat (SSR)-based TC-HARQ are developed in terms of bit error rate (BER), frame error rate (FER), and throughput. The performance predicted by these bounds are compared with simulation results and show close match in high signal to noise ratio (SNR) regions. The proposed bounds therefore provide good estimates on the error correction performance of TC-HARQ in high SNR regions where simulations are difficult to obtain reasonable results.","Title: Multiple hierarchical image transmission over wireless channels\nYear: 1999\n\nAbstract: In this paper, we present a multiple hierarchical coding and transmission scheme in which both the fragile structure of set partitioning in hierarchical trees (SPIHT) source coding and the unequal importance of bits in the coded bitstream have been taken into account. Multiple subsampling is applied to split the wavelet coeffcients of the original image source into multiple subsources so that each subsource is a crude representation of the original image. The sequential dependence of coded bitstream is broken. As a result, the error propagation is limited to a single subsource which is also coded with SPIHT to achieve desired coding performance. Cyclic redundancy coder/rate compatible punctured convolutional coder (CRC/RCPC) channel coding has been used to offer unequal error protection (UEP) to the multiple coded bitstreams. In each substream all the bits in the same bit layer are protected with the same channel code. The higher the bit-layer, the more the channel coding protects. Experimented results show that this new scheme has a good error resilient performance over wireless channels with time varying and bursty errors characteristics. In particular the reconstructed images often demonstrate good visual quality","Title: Inter-slice Resolution Improvement of Lung 4D-CT via Adaptively Patch Partition and Sparse Representation\nYear: 2013\n\nAbstract: Lung four-dimensional computer tomography (4D-CT) data resolution enhancement is helpful for lung cancer accurate radiotherapy. Sparse representation based algorithm has been proposed to reconstruct the resolution enhancement image, and achieved state-of-art performance. In this paper, based on the sparse representation algorithm, we present an adaptively patch partition approach to divide the slices into adaptively scaled patches. This approach will catch more anatomical nuances and improve the reconstruction. The quad tree-based algorithm is employed in our method to partition the slices. Moreover, a jointly intensity-feature homogeneity is defined to determinate the patch division criterion. The effectiveness of the proposed method is demonstrated by the experiments.","Title: Distributed turbo product codes with soft decode-and-forward and power allocation\nYear: 2013\n\nAbstract: In this paper, we consider a cooperative coding system based on the Distributed Turbo Product Codes DTPC with the extended Bose Chaudhuri Hocquenghem eBCH component codes. To deal with the unreliable decoding at the relay and enhance the overall decoding at the destination, we propose and study two techniques including soft information relaying and power allocation. First, at the relay, the Chase II algorithm and syndrome decoding are used to obtain the reliability values of the source data. This soft information is further exploited to generate new soft incremental redundancy for relaying. Second, to alleviate the error propagation, a method of power allocation between the source and relay is proposed. This method turns out to be very effective compared with the optimal solution from exhaustive search. The system performance in various conditions is presented and compared with extensive simulation.","Title: Trust in Knowledge Flow Networks\nYear: 2005\n\nAbstract: An ideal knowledge flow network passes right knowledge to the right person at the right time. Trust between knowledge nodes influences the efficiency of knowledge interchange in an organization. This paper presents a trust model for knowledge flow networks based on knowledge interaction experiences. Simulations show that, compared to the approach of randomly routing, the strategy using trust to help construct knowledge flow network is feasible and effective.","Title: Power Allocation for Distributed Turbo Product Codes (DTPC)\nYear: 2010\n\nAbstract: In this paper we investigate the effect of power allocation on the performance of the Distributed Turbo Product Code (DTPC) system. We study the error propagation on distributed coding systems when the relay makes erroneous decisions and present a simple power allocation method to alleviate the effect of relay decoding errors on the iterative decoding at the destination. We validate this method with results of an exhaustive search and compare its performance with the fixed power assignments for DTPC system with Decode and Forward (DF) and Soft Decode and Forward (SDF) relaying protocols. Compared to the fixed power assignment, the proposed method for power allocation shows a performance gain of 1.2dB at 10(-4) Bit Error Rate (BER).","Title: Diversity order analysis of a sub-optimal transmit antenna selection strategy for non-regenerative MIMO relay channel\nYear: 2009\n\nAbstract: This paper proposes a novel sub-optimal transmit antenna selection (TAS) strategy for non-regenerative half-duplex MIMO relay channel. While antenna selection is a sub-optimal form of beamforming, it still enjoys the advantage of tractable optimization and low feedback overhead. The diversity order of this proposed strategy is derived to prove that it can achieve the full diversity order as the optimal strategy with only a small performance loss. Furthermore, it is shown that our scheme lead to a reduction of complexity in terms of time slots for SNR estimation when the number of the transmit antennas are more than two. Monte Carlo simulation results of outage probability are presented to demonstrate its advantage over the other two conventional TAS schemes.","Title: Constrained decoding for turbo-CRC code with high spectral efficient modulation\nYear: 2005\n\nAbstract: In this paper, we propose a constrained decoding algorithm for turbo-CRC codes with high spectral efficient modulation. We follow a data structure adopted in 3GPP in which the large data frame used for turbo coding consists of multiple CRC packets. First, we modify the turbo encoder by introducing an additional interleaver to permute correctly decoded bits at early stages of decoding over the entire frame. Then, we propose a constrained decoding algorithm at the receiver, making use of the information of correctly decoded bits to help the decoding of other bits and reduce the complexity. Experimental results demonstrate the excellent performance of the entire system. In addition, the error localization property inherent in the system may benefit other applications such as ARQ.","Title: Joint Source and Space Time Decoding over Fading Channels\nYear: 2008\n\nAbstract: For high data rate communications, variable length codes (VLC) and multiple input multiple output (MIMO) techniques are required in the application layer and the physical layer, respectively. In this paper, we study the joint decoding for systems that consist of reversible VLC (RVLC) as the source codes and recursive space time trellis codes (STTC) as the coded modulation. The maximum a posteriori probability (MAP) decoding algorithm is modified to accommodate issues including the inseparable systematic information, the unsymmetric trellis structure, and information in both bit and symbol domains. Further, by converting extrinsic information based on the modulation mode and the mapping method, iterative information exchange can be performed so as to fully utilize the redundancy in both RVLC and recursive STTC. The performance of the proposed joint decoding is evaluated over both rapid fading and quasi- static flat fading channels, which shows significant improvement in coding gain in comparison with the non-iterative receiver.","Title: Differential detection of space-time spreading with two transmit antennas\nYear: 2006\n\nAbstract: A differential detection scheme for space-time spreading with two transmit antennas is proposed. The scheme does not require channel state information at either the transmitter or the receiver. With segmentation and preamble symbols padded at the transmitter, the receiver recovers the information using differential detection. Both phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals are considered. The proposed scheme achieves two-level transmit diversity gain with low complexity and saves the use of channel estimation, while having about 3 dB performance loss as compared to the coherent detection scheme. When multiple receive antennas exist, additional receive diversity gain can be achieved along with the transmit diversity gain. The scheme works fine under block-fading channel as well as slow Rayleigh fading channel, which is a popular scenario for high-rate data communications. The system performance for different segment sizes, channel fading speeds, modulation methods, and numbers of receive antennas is studied through simulations.","Title: High performance stream query processing with correlation-aware partitioning\nYear: 2013\n\nAbstract: State-of-the-art optimizers produce one single optimal query plan for all stream data, in spite of such a singleton plan typically being sub-optimal or even poor for highly correlated data. Recently a new stream processing paradigm, called multi-route approach, has emerged as a promising approach for tackling this problem. Multi-route first divides data streams into several partitions and then creates a separate query plan for each combination of partitions. Unfortunately current approaches suffer from severe shortcomings, in particular, the lack of an effective partitioning strategy and the prohibitive query optimization expense. In this work we propose the first practical multi-route optimizer named <u>c</u>orrelation-aware <u>m</u>ulti-<u>r</u>oute stream query optimizer (or CMR) that solves both problems. By exploiting both intra- and inter-stream correlations of streams, CMR produces effective partitions without having to undertake repeated expensive query plan generation. The produced partitions not only are best served by distinct optimal query plans, but also leverage the partition-driven pruning opportunity. Experimental results with both synthetic and real life stream data confirm that CMR outperforms the state-of-the-art solutions up to an order of magnitude in both the query optimization time and the run-time execution performance.","Title: Evaluation And Application Of A Hybrid Brain Computer Interface For Real Wheelchair Parallel Control With Multi-Degree Of Freedom\nYear: 2014\n\nAbstract: There have been many attempts to design brain-computer interfaces (BCIs) for wheelchair control based on steady state visual evoked potential (SSVEP), event-related desynchronization/synchronization (ERD/ERS) during motor imagery (MI) tasks, P300 evoked potential, and some hybrid signals. However, those BCI systems cannot implement the wheelchair navigation flexibly and effectively. In this paper, we propose a hybrid BCI scheme based on two-class MI and four-class SSVEP tasks. It cannot only provide multi- degree control for its user, but also allow the user implement the different types of commands in parallel. In order for the subject to learn the hybrid mental strategies effectively, we design a visual and auditory cues and feedback-based training paradigm. Furthermore, an algorithm based on entropy of classification probabilities is proposed to detect intentional control (IC) state for hybrid tasks, and ensure that multi-degree control commands are accurately and quickly generated. The experiment results attest to the efficiency and flexibility of the hybrid BCI for wheelchair control in the real- world.","Title: A novel feature fusion approach based on blocking and its application in image recognition\nYear: 2006\n\nAbstract: According to the idea of canonical correlation analysis, a block-based method for feature extraction is proposed. The main process can be explained as follows: extract two groups of feature vectors from different blocks which belong to the same pattern; and then extract their canonical correlation features to form more effective discriminant vectors for recognition. To test this new approach, the experiment is performed on ORL face database and it shows that the recognition rate is higher than that of algorithm adopting single feature.","Title: Channel Mean Forwarded Regenerative Cooperative Demodulation in OFDM Systems\nYear: 2008\n\nAbstract: In this paper, we propose a channel mean forwarded (CMF) relay scheme with gammamin-MRC demodulator at the destination for cooperative OFDM systems. For regenerative cooperative communications, i.e., decode-and-forward (DF) scheme, using the classical MRC demodulator, may not give satisfactory system performance since the channel quality of the source-to-relay (S-R) link is not exploited at the destination. On the other hand, near-optimal lambda-MRC and cooperative-MRC (C-MRC) which are proposed to achieve full diversity, require the perfect instantaneous channel state information (CSI) of the S-R link being available at the destination. In our CMF scheme, the S-R channel is based on the classical first-order auto-regression AR(1) models, where the channel mean can be tracked. Based on the forwarded CSI of the S-R link, the destination can use gammamin-MRC demodulator, which combines signals coming from the source-to-relay-to-destination (S-R-D) link and the source- to-destination (S-D) link by appropriately predicted weights to achieve the full diversity. Simulations show that the performance of this CMF scheme is better than the classical MRC scheme. In slow-fading scenarios, the performance of this CMF scheme can approach the one that the perfect square of the channel norm of the S-R link is available at the destination. Even in fast-fading scenarios, the CMF scheme can also achieve better performance than the classical MRC scheme. In addition, we provide the performance of the direct one-hop scheme for fair comparison as well.","Title: Analysis on the impact factors of low-rent housing residents' income in Shanghai based on BP neural network.\nYear: 2011\n\nAbstract: Low-rent housing system is the necessary guarantee of building harmonious society and the urgent demand of establishing and perfecting social security system. It has realistically significance to study the low-rent housing by multi-level and multi-angle. Based on the data of income for low-rent housing residents, applying BP neural network model, the quantitative analysis on the influence of income factors of low-rent housing residents in Shanghai was given, and the mechanism of each factor was studied by further analysis. The result showed that BP neural network model could be successful to study the income of Shanghai low-rent housing residents. There are different influences and mechanisms on each factor to the segment income and total income. Furthermore, the top two influential factors on the wage income is the employment and marital status, and transfer income has the closest relationship with sexuality, region and employment status. Therefore, it reflects that the level of employment and social welfare play important roles for the income of low-rent housing residents. © 2011 IEEE.","Title: Turbo Codes Based Image Transmission for Channels with Both Random Errors and Packet Loss\nYear: 2007\n\nAbstract: In this paper, we propose an unequal error protection (UEP) framework for progressive image transmission over wireless networks with both random errors and packet loss. By sophisticatedly interleaving each coded frame, the packet loss is converted into randomly punctured bits in a turbo code. Therefore, error control of channels with both types of distortions is equivalent to dealing with random bit errors only through turbo codes with reduced rates. To optimally allocate the overall transmission rate between the source and channel codes, a genetic algorithm (GA) based method is proposed which not only largely reduces the optimization complexity but also gives results close to the brute force search in tested scenarios. Then, we extend the UEP to a product code scheme by adding Reed-Solomon (RS) code across the frames. An efficient rate allocation method for this product code with the use of interleaving is further presented. The effectiveness of the proposed schemes is demonstrated with extensive simulation results.","Title: Distributed STBC With Soft Information Relay Based on Gaussian Approximation.\nYear: 2012\n\nAbstract: We consider a system where the source transmits signals to the destination via two-relays where distributed space time block codes (STBC) are used. It is assumed that the signals are coded at the source and decoded at the relays. In the general case, the decoding at relays might not be perfect and hence the soft information is forwarded. Considering the independent Rayleigh channels and using the ...","Title: Symbol Detection with Network Coding in Wireless Channels\nYear: 2013\n\nAbstract: For multi-sources transmitting to a common sink with assistance of relays where network coding is used, different symbols may experience different fading and noise levels, and there is a need to calculate the average symbol detection error probability at the receiver. In this letter, we present a method that closely bounds the error performance when log-likelihood ratio (LLR) detection is used. The method integrates two techniques including the union bound based on the bit-level input-output weight enumerate function (IOWEF) in coding and the maximum ratio combining (MRC) in diversity analysis. The method is applicable to any network coding matrix used at relay.","Title: Differential Space-Time Spreading With Segment Selective Repeat-Based Automatic Repeat Request\nYear: 2008\n\nAbstract: In this paper, we first propose differential space-time spreading (DSTS) with multiple transmit antennas. With the assumption of no channel state information at either the transmitter or the receiver, the DSTS signal is differentially encoded and decoded. The proposed method achieves full transmit diversity gains. As compared to the coherent space-time spreading (CSTS) method, the proposed scheme has 3-dB performance degradation, but avoids the demand of perfect channel estimation. We then combine DSTS with segment selective repeat (SSR)-based automatic repeat request (ARQ). By utilizing the estimated channel gain of DSTS at the receiver, only the worse corrupted portion of the data is retransmitted upon error to improve efficiency. It is shown that the proposed DSTS with SSR-based ARQ achieves higher throughput than DSTS with Type-I ARQ while maintaining similar bit error rate (BER).","Title: Using genetic algorithm to implement cost-driven web service selection\nYear: 2007\n\nAbstract: Web services composition has been one of the hottest research topics. But with the ever-increasing number of functional similar web services being made available on the Internet, there is a need to be able to distinguish them using a set of well-defined Quality of Service (QoS) criteria. The cost is the primary concern of many business processes. This paper proposes a new solution using Genetic Algorithm (GA) to implement cost-driven web service selection. GA is utilized to optimize a business process composed of many service agents (SAgs). Each SAg corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using a local service selection strategy. The global optimal solution might also be achieved with proper GA parameters.","Title: ShanghaiGrid Portal: The Current Stage of Building Information Grid Portal\nYear: 2004\n\nAbstract: Grid portal gives a center access point to access Grid applications and resources., Currently the existing Grid portals are mainly designed for computational Grids which put focus on how to view files, submit and monitor jobs. That alleviate the complexity of using the Grid application. The ShanghaiGrid is an Information Grid which puts focus on how to provide various services in Grid environment to public rather than to scientists. In ShanghaiGrid portal the portal information service, workflow service, and transaction service are very important to achieve the goal of building a web interface for citizens to seamlessly and transparently use the Grid services located in ShanghaiGrid environment. This paper reports our current research and implementation of the ShanghaiGrid portal.","Title: An ECA-Rule-Based workflow management approach for web services composition\nYear: 2005\n\nAbstract: Composing autonomous Web services to achieve new function, is receiving more and more attention in recent years in several computer science communities. The workflow model is the most important part in Web services composition. However, the existing approaches have difficulties in the process because their complexity. In this paper, we have developed an ECA (Event-Condition-Action)-rule-based workflow management system (EWMS) for Web service composition, which can help users compose Web services conveniently. We also use an image processing application to validate the feasibility and efficiency of our system.","Title: Turbo Decoder For Low-Power Ultrawideband Communication Systems\nYear: 2008\n\nAbstract: A new method to reduce the computational complexity of the turbo decoding in ultrawideband (UWB) orthogonal frequency division multiplexing (OFDM) system is proposed. Existing stopping techniques for turbo decoding process using constrained decoding assume fixed signal-to-noise ratio (SNR) for all the OFDM symbol bits so they fail to yield an acceptable bit-error rate (BER) performance in multicarrier systems. In this paper, we propose a bit-level stopping technique for turbo decoding process based on the constrained decoding method. In this technique, we combine the cyclic redundancy check (CRC) with an adaptive threshold on the log likelihood ratio (LLR) on each subcarrier to detect for convergence. The threshold is adaptive in the sense that the threshold on the LLR of a bit is determined by the average SNR of the OFDM symbol and the channel gain of the transmission subcarrier. Results show that when the channel state information (CSI) is used to determine the threshold on LLR, the stopping technique can reduce the computational complexity by about 0.5-2.5 equivalent iterations compared to GENIE turbo without degradation in the BER performance. Copyright (C) 2008 E. A. Obiedat and L. Cao. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.","Title: Joint decoding of concatenated VLEC and STTC system\nYear: 2008\n\nAbstract: We consider the decoding of wireless communication systems with both source coding in the application layer and channel coding in the physical layer for high-performance transmission over fading channels. Variable length error correcting codes (VLECs) and space time trellis codes (STTCs) are used to provide bandwidth efficient data compression as well as coding and diversity gains. At the receiver, an iterative joint source and space time decoding scheme are developed to utilize redundancy in both STTC and VLEC to improve overall decoding performance. Issues such as the inseparable systematic information in the symbol level, the asymmetric trellis structure of VLEC, and information exchange between bit and symbol domains have been considered in the maximum a posteriori probability (MAP) decoding algorithm. Simulation results indicate that the developed joint decoding scheme achieves a significant decoding gain over the separate decoding in fading channels, whether or not the channel information is perfectly known at the receiver. Furthermore, how rate allocation between STTC and VLEC affects the performance of the joint source and space-time decoder is investigated. Different systems with a fixed overall information rate are studied. It is shown that for a system with more redundancy dedicated to the source code and a higher order modulation of STTC, the joint decoding yields better performance, though with increased complexity.","Title: SH-MDS: A ShanghaiGrid Information Service Model\nYear: 2004\n\nAbstract: Grid computing is becoming a mainstream technology for sharing large-scale resources, accomplishing collaborative tasks and integrating distributed systems. Information Service plays a very important role in Grid Computing Environment. Through information Service Grid applications are able to exploit the knowledge about current grid status and configuration to adapt themselves to changes in heterogeneous, dynamic environments. In this paper, we propose a framework of Information Service based on the testbed ShanghaiGrid. In GT3, the Index Service in MDS can not provide a reliable indexing, while in our framework, using the notification method to contact Grid Services to Index Service to provide a reliable indexing. The information that Information Service should provide according with the ShanghaiGrid is discussed in detail.","Title: Interleaved turbo codes protection for progressive image transmission with efficient rate allocation\nYear: 2007\n\nAbstract: Instead of using product codes for progressive image transmission over noisy fading channels, we extend, in this paper, a recently proposed image transmission method by the authors by interleaving each coded packet to fading channels so that the effect of burst error can be converted into the random bit errors. As a result, the design of unequal error protection for fading channel can be unified with the rate compatible punctured turbo (RCPT) codes protection only. We show that a better performance than the product code protection can be obtained for a given channel condition. Furthermore, the proposed method is also insensitive to the channel variation. Some interesting technical components including a Genetic Algorithm (GA) based rate allocation method, using RS codes to break the error floor of the turbo codes are also discussed in the paper. The advantages of the proposed methods have been demonstrated with extensive simulation results.","Title: Performance analysis of transmit antenna selection and relay selection in two-hop multiple MIMO relaying\nYear: 2012\n\nAbstract: This paper analyzes cooperative diversity wireless networks with the application of multiple-input multiple-output (MIMO) techniques, using amplify-and-forward (AF) MIMO relaying with transmit antenna selection (TAS)/maximal-ratio combing (MRC) and relay selection (RS). The source, destination, and relays are equipped with multiple antennas, denoted by NS, ND, and NR, respectively. Specifically, the asymptotic performance is analyzed and the derived upper bound and lower bound on the diversity order leads to the conclusion that the diversity order of NSND +NRmin{NS;ND} can be achieved in the cooperative AF MIMO relaying scenario, which depends on the total number of relay antennas rather than the individual number of each relay's antennas. Numerical results that confirm our analysis are also presented in the paper.","Title: Interactive Outlier Exploration in Big Data Streams.\nYear: 2014\n\nAbstract: We demonstrate our VSOutlier system for supporting interactive exploration of outliers in big data streams. VSOutlier not only supports a rich variety of outlier types supported by innovative and efficient outlier detection strategies, but also provides a rich set of interactive interfaces to explore outliers in real time. Using the stock transactions dataset from the US stock market and the moving objects dataset from MITRE, we demonstrate that the VSOutlier system enables analysts to more efficiently identify, understand, and respond to phenomena of interest in near real-time even when applied to high volume streams.","Title: Analysis of the degree distribution for LT codes\nYear: 2014\n\nAbstract: the first type of practical fountain codes, LT codes are used in various applications. Although the performance of an LT code is determined by the parameters of the Robust Soliton Distribution RSD, this relationship remains largely unclear. In this paper, we analytically study the relationship between the mean degree value of the RSD and the parameters including the spike position and δ in RSD. Then, with obtained properties and simulation results, we further investigate the impact of these parameters on the performance of LT codes.","Title: Cross-layer optimization for 3-D video transmission over cooperative relay systems.\nYear: 2014\n\nAbstract: The rate budget constraint and the available instantaneous signal-to-noise ratio of the best relay selection in cooperative systems can dramatically impact the system performance and complexity of video applications, since they determine the video distortion. By taking into account these constrained factors, we first outline the signal model and formulate the system optimization problem. Next, we propose a new approach to cross-layer optimization for 3-D video transmission over cooperative relay systems. We propose procedures for estimation of the end-to-end instantaneous signal-to-noise ratio using an estimate of the available instantaneous signal-to-noise ratios between the source–destination, and source–relay–destination before starting to send the video signal to the best relay and destination. A novel approach using Lagrange multipliers is developed to solve the optimum bit allocation problem. Based on the rate budget constraint and the estimated the end-to-end instantaneous signal-to-noise ratio, the proposed joint source–channel coding (JSCC) algorithm simultaneously assigns source code rates for the application layer, the number of high and low priority packets for the network layer, and channel code rates for the physical layer based on criteria that maximize the quality of video, whilst minimizing the complexity of the system. Finally, we investigate the impact of the estimated the end-to-end instantaneous signal-to-noise ratio on the video system performance and complexity. Experimental results show that the proposed JSCC algorithm outperforms existing algorithms in terms of peak signal-to-noise ratio. Moreover, the proposed JSCC algorithm is found to be computationally more efficient since it can minimize the overall video distortion in a few iterations.","Title: Divergence-Based Soft Decision for Error Resilient Decentralized Signal Detection\nYear: 2014\n\nAbstract: In this paper, we consider decentralized detection where the transmission of local soft-decisions of the secondary users (SUs) to the fusion center (FC) is both rate-limited and error-prone. The quantized data to be sent from SUs should not only carry the local information but also need to be resilient to channel errors. With the assumption of independent and identical secondary user observations conditioned on signal hypothesis and binary symmetric channels (BSC) between SUs and the FC, we design local quantizers at a SU, based on two divergence metrics, namely Kullback-Leibler (KL) and Chernoff. Using convex duality, we show that a two-stage algorithm can be developed to take care of the quantization thresholding, codeword assignment, and error resilience. Specifically, we obtain the following results. First, we show that the proposed quantizer obtains increased divergence between the distributions of the demodulated data at the FC, when compared to the maximum entropy quantizer design. We also point out the fallacy of previously reported Gray code assignment to quantized data. Second, the quantizer optimally picks the repetition codeword in the case of “ideal” sensing at the sensors. Similar “channel blind” optimal quantizer design was observed in the literature for single-sensor case. Third, we derive new bit error probability (BEP) wall expression for D-bits soft-quantization, for specified probabilities of errors at the FC. The new result shows whether and when a majority logic rule is optimal at the FC.","Title: BER analysis and power allocation for cooperative diversity networks with distributed Alamouti code\nYear: 2015\n\nAbstract: In this paper, we consider the distributed Alamouti code for a cooperative diversity network consisting of a source, a non-regenerative relay, and a destination. While in the first time phase, the source radiates signals to both relay and destination; in the second time phase, the source and the relay cooperatively send signals to the destination by using an Alamouti code. Considering the amplify-and-forward protocol and independent Rayleigh fading, we first derive the exact average bit error rate performance in a single integral expression so that the system performance can be numerically evaluated. Then, based on a new approximation method of the Marcum Q-function, we also give a tight upper bound for the system performance with a summation of a number of series components. We demonstrate through simulation that, in various operation scenarios with different channel quality and types of modulation, the results of the exact bit error rate expression accurately matches the simulation results, and the bound is tighter and more robust than existing approximation methods. Finally, we show that the analytic work also provides a method for the optimal allocation of power between the source and the relay in the second time phase. Copyright © 2013 John Wiley & Sons, Ltd.","Title: Name Disambiguation By Collective Classification\nYear: 2014\n\nAbstract: Disambiguating person names in a set of documents (e.g. research papers or Web pages) is a critical problem in many knowledge management applications. The phenomenon of ambiguity will deteriorate the quality of service, such as the scholar searching and expert finding. Despite years of research, this problem remains largely unsolved, where the unknown number of persons with the same name and the information scarcity in documents pose many difficulties and challenges. In this paper, we formalize name disambiguation as a collective classification problem and solve it using a simple yet effective iterative classification algorithm, referred as ICAND (i.e. Iterative Classification Algorithm for Name Disambiguation). Experimental results on researcher dataset show that the proposed approach can significantly outperform several baseline methods.","Title: Multiple UAVs hierarchical dynamic task allocation based on PSO-FSA and decentralized auction\nYear: 2014\n\nAbstract: Multi-UAVs dynamic task allocation is a hot issue currently in the field of unmanned combat command and control. The dynamic task allocation problem for unexpected new tasks appear in battle field is the focus of this study. In order to fulfill the requirements of time and communication complexity, firstly, this paper establishes a state information model of UAV and UAV groups based on the grouping of tasks and UAVs. Secondly, this paper propose a mixed dynamic task allocation method to decompose the problem into two low-level problems including group-level task allocation and member-level task allocation, which are solved by using improved PSO-FSA and distributed auction algorithm. Finally, the simulation experiments prove the effectiveness of the algorithm proposed in this paper and that it can reduce the size of dynamic task allocation, which leads to the reduction of time complexity and communication complexity.","Title: Detecting moving object outliers in massive-scale trajectory streams\nYear: 2014\n\nAbstract: The detection of abnormal moving objects over high-volume trajectory streams is critical for real time applications ranging from military surveillance to transportation management. Yet this problem remains largely unexplored. In this work, we first propose classes of novel trajectory outlier definitions that model the anomalous behavior of moving objects for a large range of real time applications. Our theoretical analysis and empirical study on the Beijing Taxi and GMTI (Ground Moving Target Indicator) datasets demonstrate its effectiveness in capturing abnormal moving objects. Furthermore we propose a general strategy for efficiently detecting the new outlier classes. It features three fundamental optimization principles designed to minimize the detection costs. Our comprehensive experimental studies demonstrate that our proposed strategy drives the detection costs 100-fold down into practical realm for applications producing high volume trajectory streams to utilize.","Title: Personalized paper recommendation in online social scholar system\nYear: 2014\n\nAbstract: This paper presents a practical paper recommender system, which aims to provide personalized research paper recommendations to users within an online social scholar system. As an online recommender system, there are three basic problems we need to tackle: 1) How to formalize and solve the recommendation problem; 2) How to achieve real time recommendation; and 3) How to interact with users. In our work, we take the personalized paper recommendation as a ranking problem with respect to users' research interests, and employ a supervised learning to rank approach to solve the problem. However, most previous learning to rank methods rely on manually labeled training data which are both expensive and limited in size. We propose automatical training data construction by mining the existing large scale academic network, and extract various heterogeneous features for learning. With the learned model, we conduct real time personalized recommendation based on our novel efficient candidate generation approach. In addition, update recommendation is employed to interact with users according to different types of user feedbacks. Finally, we demonstrate the effectiveness of our system by both offline and online evaluation.","Title: Cross-Tier Interference Coordination Of Macro Muting Based On Adaptive Cqi Hysteresis In Hspa Heterogeneous Network\nYear: 2013\n\nAbstract: Heterogeneous network (HetNet) has been studied earlier in the context of LTE. But lately, there are also some discussions about HetNet in HSPA. Cross-tier interference (CTI) is an annoying issue to be investigated in the co-channel HSPA HetNet (CHH) scenario. In this paper, we will focus on the downlink CTI problem in CHH and propose a solution to mitigate it. Our scheme involves the macro muting (MM) in which macro NodeB will mute itself at some certain sub-frames to reduce the CTI level in the system. We also enhance the MM scheme by introducing the adaptive CQI hysteresis (ACH) mechanism to avoid the issue that the low power node (LPN) in HetNet may use the improper CQI for transmitting when MM is implemented. Simulation results will show the benefits of our proposed scheme.","Title: Architecture approach for ICT supply chain integrity\nYear: 2013\n\nAbstract: With the rapid pace of globalization and outsourcing, supply chain integrity of ICT system is gaining more and more attentions. Integrity of ICT Supply Chain has a slightly different focus from network security. Due to the increasing complexity and formidable cost and timing, it's by no means enough to guarantee the integrity of a modern ICT product through technical testing and vendor screening. An architectural approach, named as Architectural Solution Integration (ASI), has been proposed to improve the supply chain integrity during the topology design stage of ICT systems. In this paper, the architecture design methodology for ASI is proposed. Supplier trust model and supply chain integrity model are established with an algorithm based on ranked attack graph to quantitatively evaluate the integrity of ICT supply chain. Finally, a case study is presented to demonstrate the feasibility of the proposed ICT supply chain integrity model and evaluation algorithm, which are the key elements of the ASI approach.","Title: Can Your Friends Predict Where You Will Be?\nYear: 2014\n\nAbstract: With the development of mobile device and wireless networks, user location becomes increasingly valuable in enhancing user experience, system performance and resource allocation. Location-based services have been not only an important perspective of social media, but also a significant contributor to big data analysis. Location prediction, as an interesting topic, can help improve system performance and user experience in location-based services. Existing algorithms on such prediction focus mostly on exploring regularity in users' movement history without taking advantage of the research on social networks, which can provide information on other factors such as peer influence in human mobility. In this work, the aim is to propose an enhanced location prediction model based on both users' mobility patterns and social network information and the proposed algorithm shows a significant improvement over existing ones.","Title: Complex event analytics: online aggregation of stream sequence patterns\nYear: 2014\n\nAbstract: Complex Event Processing (CEP) is a technology of choice for high performance analytics in time-critical decision-making applications. Yet while effective technologies for complex pattern detection on continuous event streams have been developed, the problem of scalable online aggregation of such patterns has been overlooked. Instead, aggregation is typically applied as a post processing step after CEP pattern detection, leading to an extremely ineffective solution. In this paper, we demonstrate that CEP aggregation can be pushed into the sequence construction process. Based on this insight our A-Seq strategy successfully aggregates sequence pattern online without ever constructing sequence matches. This drives down the complexity of the CEP aggregation problem from polynomial to linear. We further extend our A-Seq strategy to support the shared processing of concurrent CEP aggregation queries. The A-Seq solution is shown to achieve over four orders of magnitude performance improvement for a wide range of tested scenarios compared to the state-of-the-art solution.","Title: Non-Symmetric Decompanding for Improved Performance of Companded OFDM Systems\nYear: 2007\n\nAbstract: Recent work in literature suggests the use of companding transforms to reduce the peak to average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. However, previous performance evaluations assume the availability of infinite bandwidth. In bandlimited conditions, the performance deteriorates as a result of filtering out the out-of-band radiation (OBR). In this letter, we first study the effect of filtering on the performance of various companding techniques. We further propose a simple yet very effective method to overcome this performance degradation. The essential idea is to use companding and decompanding transforms which are not exact inverse of each other. Simulation results show that the proposed scheme significantly outperforms the previous schemes under more realistic channel conditions.","Title: Joint Distributed Space-Time Block Coding with Distributed Turbo Product Code (DSTBC-DTPC)\nYear: 2011\n\nAbstract: We propose new joint distributed Space-Time Block Code (STBC)-Distributed Turbo Product Code (DTPC) by generating the vertical parity on the relay and transmitting it to the destination using STBC on the source and relay. We tested our proposed system in a fast fading environment on the three channels connecting the three nodes in the cooperative network. Results show an overall gain that can reach 3.5dB over the non-cooperative system at 10-5 Bit Error Rate (BER).","Title: Multi-scale image compressed sensing with optimized transmission\nYear: 2013\n\nAbstract: Existing works in image compressed sensing (CS) often focus on improving the rate-distortion sensing performance but have less consideration of the effect of channel errors on the transmission of CS measurements. This paper explores how the transmission channel errors affect the PSNR performance of the quantized sensing measurements and then increases the resistance of the transmitted data to the noisy channel. We show that the multi-scale block based compressed sensing (MSBCS) using quantization with differential phase code modulation (DPCM), though achieves compression efficiency higher than the regular scalar quantization-based CS, is more vulnerable to channel errors. To improve the error resistance, a method of optimized energy allocation across bit-layers in quantized measurements is presented, which leads to a large PSNR performance improvement for CS data transmission in wireless environment.","Title: Distributed Turbo Product Codes over Multiple Relays\nYear: 2010\n\nAbstract: In this paper, we propose a Distributed Turbo Product Code (DTPC) over cooperative network using block Bose Chaudhuri Hochquenghem (BCH) codes as component codes. The source broadcasts extended BCH coded frames to the destination and nearby relays. After decoding the received sequences, each relay constructs a product code by arranging the corrected bit sequences in rows and re-encoding them vertically using BCH as component codes to obtain an Incremental Redundancy (IR) for source's data. To obtain independent vertical parities from each relay in the same code space, different circular interleavers are proposed to interleave BCH rows before reencoding vertically. A modified turbo product decoder to cope with Multiple Vertical Parities (MVP) is used at the destination to iteratively decode the systematic data from the source and the vertical parities generated by the relays. Simulation results in Additive White Gaussian Noise (AWGN) channel using network scenarios show 0.3-0.5dB gain improvement in Bit Error Rate (BER) performance over the non-cooperative Turbo Product Codes (TPC).","Title: Soft Incremental Redundancy for Distributed Turbo Product Codes\nYear: 2010\n\nAbstract: In this paper, we propose a distributed turbo product code (DTPC) with soft information relaying over cooperative network using block extended bose Chaudhuri Hochquenghem (EBCH) codes as component codes. The source broadcasts extended EBCH coded frames to the destination and to a preassigned relay. After soft-decoding the received sequences and obtaining the log-likelihood ratio (LLR) values, the relay constructs a product code by arranging the decoded bit sequences in rows and re-encoding them along the columns using a novel soft block encoding technique to obtain soft parity bits with different reliabilities that can be used as soft incremental redundancy (IR) for source's data which is forwarded to the destination. A modified turbo product decoder to cope with the data received over different channels and thus having different reliabilities is used at the destination. We compared the simulation results in additive white Gaussian noise (AWGN) channel using network scenarios with our previous work for decode and forward (DF) DTPC and with non-cooperative case. Results show 0.5 dB gain improvement over the non-cooperative turbo product codes (TPC) at bit error rate (BER) 10-4. In addition, the BER performance is less affected by the decoding errors at the relay.","Title: Location dependent optimal relay selection in mobile cooperative environment\nYear: 2012\n\nAbstract: This paper proposes an optimal relay selection criteria based on the location of the relay (0 ≤ λ ≤ 1) relative to source and destination in the cooperative coded system. The proposed optimization algorithm employs distributed turbo product coding technique with hard and soft decoding. It is shown that the link quality depends on the location of the relay which in turn affects overall system Bit Error Rate (BER) performance. The simulation model creates several scenarios for location of intermediate relays when the inter-user channel is experiencing distortion in presence of different Signal to Noise Ratio (SNR)s. It is observed that the link performance degrades as the relay proximity changes with respect to the source and the destination. The relay selection optimization algorithm provides the participating nodes necessary information to select neighboring nodes depending on link quality, thus lowering the BER and increasing the overall network capacity.","Title: The Assimilation of Jason-2 Significant Wave Height Data in the North Indian Ocean Using the Ensemble Optimal Interpolation\nYear: 2016\n\nAbstract: A parallel module of data assimilation based on the ensemble optimal interpolation (EnOI) scheme has been developed and implanted into the third-generation spectral wave model NOAA WAVEWATCH III version 3.14 (hereafter NWW3). This paper presents an evaluation of preliminary experiments assimilating satellite altimeter significant wave height (SWH) data into the NWW3-EnOI wave assimilation system. Data from Jason-2 are used mainly for assimilation and from Jason-1 for validation. The target computational domain for the experiments is north of 15° S in the Indian Ocean, which is nested into a global implementation of NWW3. A stationary ensemble of model output SWH sampled during a long time integration was examined first, showing that the ensemble error covariances were of significant flow dependence due to the monsoon climate. Experimental results by the NWW3-EnOI were validated against a number of moored buoys situated in the Bay of Bengal and east of the Arabian Sea. It was found that the assimilation of altimeter SWH reduced the root mean square errors in analyzed SWH by approximately 20%-60% at different validation stations. The improvement in model skill can be retained throughout the forecast period. The assimilation is found to have the greatest impact of the assimilation in areas and seasons where and when sea states are dominated by swells.","Title: A DAISY descriptor based multi-view stereo method for large-scale scenes.\nYear: 2016\n\nAbstract: •An improved patch based MVS method by a novel photometric discrepancy function.•Proposed a new corresponding point matching method based on the DAISY descriptor.•Proposed a new photometric discrepancy function based on DAISY descriptor.","Title: Online Outlier Exploration Over Large Datasets\nYear: 2015\n\nAbstract: Traditional outlier detection systems process each individual outlier detection request instantiated with a particular parameter setting one at a time. This is not only prohibitively time-consuming for large datasets, but also tedious for analysts as they explore the data to hone in on the appropriate parameter setting and desired results. In this work, we present the first online outlier exploration platform, called ONION, that enables analysts to effectively explore anomalies even in large datasets. First, ONION features an innovative interactive anomaly exploration model that offers an \\\"outlier-centric panorama\\\" into big datasets along with rich classes of exploration operations. Second, to achieve this model ONION employs an online processing framework composed of a one time offline preprocessing phase followed by an online exploration phase that enables users to interactively explore the data. The preprocessing phase compresses raw big data into a knowledge-rich ONION abstraction that encodes critical interrelationships of outlier candidates so to support subsequent interactive outlier exploration. For the interactive exploration phase, our ONION framework provides several processing strategies that efficiently support the outlier exploration operations. Our user study with real data confirms the effectiveness of ONION in recognizing \\\"true\\\" outliers. Furthermore as demonstrated by our extensive experiments with large datasets, ONION supports all exploration operations within milliseconds response time.","Title: Decoding of short LT codes over BIAWGN channels with Gauss-Jordan elimination-assisted belief propagation method\nYear: 2015\n\nAbstract: Belief propagation (BP) algorithm has been widely used for decoding LT codes. It is well known that the premature termination of the BP decoding due to the lack of degree one symbols in the ripple impairs the decoding performance of the code. This problem has been well studied and tackled for binary erasure channel (BEC). However, for binary input additive white Gaussian noise (BIAWGN) channels, the issue still remains unaddressed. In this paper, we propose Gauss-Jordan elimination (GJE)-assisted BP algorithm to address this problem and study its decoding performance for short LT codes over BIAWGN channels. The use of GJE can effectively help the BP decoder continue the decoding process whenever it gets stuck due to the premature termination. Simulation results show that, under the same channel conditions and transmission overheads, the bit error rate (BER) performance obtained using the GJE-assisted BP method significantly outperforms the one obtained using the traditional BP algorithm.","Title: On unequal error protection raptor codes\nYear: 2015\n\nAbstract: Raptor codes are the most advanced fountain codes that can provide dynamically changeable code rate and have linear time encoding and decoding. In multimedia communications and different other areas, it is desired that channel codes can provide the property of unequal error protection (UEP). In this paper, we study two methods to provide UEP Raptor codes on the binary erasure channel (BEC): (1) Using UEP precode (2) Using UEP LT codes. With analysis and thorough simulation we compare the two methods and we conclude that applying UEP in the precode can achieve lower bit erasure rate (BER) for both the more important bits (MIB) and less important bits (LIB).","Title: A label compression coding approach through maximizing dependence between features and labels for multi-label classification\nYear: 2015\n\nAbstract: Label compression coding strategy aims at multi-label classification problems with high-dimensional and/or sparse label vectors. Without deteriorating classification performance significantly, its efficiency depends on two key aspects: coding raw binary label vectors into real or binary codewords shortly, and decoding binary label vectors from predicted codewords speedily, which reduce the computational costs in training and testing procedures respectively. In this paper, we propose a novel label compression coding method for multi-label classification, which maximizes dependence between features and labels using Hilbert-Schmidt independence criterion and thus considers both feature and label information simultaneously. Via solving an eigenvalue problem, our method results in a small-scale coding matrix and a fast decoding operation. The experiments on ten various bench-mark data sets illustrate that our proposed technique is superior to three existing approaches, including compressive sensing based method, principal label space transformation technique and its conditional version, according to five ranking-based and instance-based performance evaluation measures.","Title: Rate and power efficient image compressed sensing and transmission.\nYear: 2016\n\nAbstract: This paper presents a suboptimal quantization and transmission scheme for multiscale block-based compressed sensing images over wireless channels. The proposed method includes two stages: dealing with quantization distortion and transmission errors. First, given the total transmission bit rate, the optimal number of quantization bits is assigned to the sensed measurements in different wavelet sub-bands so that the total quantization distortion is minimized. Second, given the total transmission power, the energy is allocated to different quantization bit layers based on their different error sensitivities. The method of Lagrange multipliers with Karush-Kuhn-Tucker conditions is used to solve both optimization problems, for which the first problem can be solved with relaxation and the second problem can be solved completely. The effectiveness of the scheme is illustrated through simulation results, which have shown up to 10 dB improvement over the method without the rate and power optimization in medium and low signal-to-noise ratio cases. (C) 2016 SPIE and IS&T","Title: Multi-query outlier detection over data streams: poster.\nYear: 2016\n\nAbstract: Real-time analytics of anomalous phenomena on streaming data typically relies on processing a large variety of continuous outlier detection requests, each configured with different parameter settings. The processing of such complex outlier analytics workloads is resource consuming due to the algorithmic complexity of the outlier mining process. In this work we propose a sharing-aware multi-query execution strategy for outlier detection on data streams called SOP. The key insight of SOP is to transform the problem of handling a multi-query outlier analytics workload into a single-query skyline computation problem. SOP achieves minimal utilization of both computational and memory resources for the processing of these complex outlier analytics workload.","Title: Sharing-Aware Outlier Analytics over High-Volume Data Streams.\nYear: 2016\n\nAbstract: Real-time analytics of anomalous phenomena on streaming data typically relies on processing a large variety of continuous outlier detection requests, each configured with different parameter settings. The processing of such complex outlier analytics workloads is resource consuming due to the algorithmic complexity of the outlier mining process. In this work we propose a sharing-aware multi-query execution strategy for outlier detection on data streams called SOP. A key insight of SOP is to transform the problem of handling a multi-query outlier analytics workload into a single-query skyline computation problem. We prove that the output of the skyline computation process corresponds to the minimal information needed for determining the outlier status of any point in the stream. Based on this new formulation, we design a customized skyline algorithm called K-SKY that leverages the domination relationships among the streaming data points to minimize the number of data points that must be evaluated for supporting multi-query outlier detection. Based on this K-SKY algorithm, our SOP solution achieves minimal utilization of both computational and memory resources for the processing of these complex outlier analytics workload. Our experimental study demonstrates that SOP consistently outperforms the state-of-art solutions by three orders of magnitude in CPU time, while only consuming 5% of their memory footprint - a clear win-win. Furthermore, SOP is shown to scale to large workloads composed of thousands of parameterized queries.","Title: Hard decision based distributed detection in multi-sensor system over noise correlated sensing channels\nYear: 2016\n\nAbstract: In spite of the spectrum sensing importance, small part of the literature deals with the case of dependency between sensors' observations. In this paper, Bayes criterion for minimizing the probability of error (Pe) is used to find the distributed decision rule at each sensor in a binary hypothesis multi-sensor system, while considering the correlation over the sensing channels. This paper proposes a new, simple, yet efficient algorithm to find the local decision rules to achieve the objective of minimizing the Pe. Upon receiving the signal, each sensor sends a local hard decision to the fusion center (FC). The FC then generates a global decision using the K-out-of-N majority rule. The derived problem formulation and the proposed algorithm can be used with any joint probability density functions and with any odd number of sensors. The proposed framework also accounts for the path attenuation effect on the global decision. The results show the effectiveness and validity of the proposed framework in practical sensor systems.","Title: Divergence and Bayes error based soft decision for decentralized signal detection of correlated sensor data\nYear: 2016\n\nAbstract: In decentralized cooperative sensing for cognitive radio, a few secondary users (SUs) sense the spectrum, process individual observation and then pass quantized data to the fusion center (FC), where the decision on signal present hypothesis or signal absent hypothesis is made. When the reporting channels between SUs and the FC are bandlimited and error prone, a quantization scheme was proposed recently based on divergence measures for independent observations. In this paper, we extend the design of quantizers to correlated sensor data. With the assumption that two SUs' observations are jointly distributed as bivariate Gaussian with identical marginals, we design quantizers based on both divergence measures and the Bayes error. Our simulation results demonstrate that a quantizer designed with the knowledge of known joint distributions outperform the quantizer designed with independent sensor data assumption. Thus, it is important to account for correlation in the quantizer design in distributed cooperative sensing.","Title: A Non-linear Label Compression Coding Method Based on Five-Layer Auto-Encoder for Multi-label Classification.\nYear: 2016\n\nAbstract: In multi-label classification, high-dimensional and sparse binary label vectors usually make existing multi-label classifiers perform unsatisfactorily, which induces a group of label compression coding (LCC) techniques particularly. So far, several linear LCC methods have been introduced via considering linear relations among labels. In this paper, we extend traditional three-layer auto-encoder to construct a five-layer one (i.e., five-layer symmetrical neural network), and then apply the training principle in extreme learning machine to determine all network weights. Therefore, a non-linear LCC approach is proposed to capture non-linear relations of labels, where the first three-layer network is regarded as a encoder and the last two layers act as a decoder. The experimental results on three benchmark data sets show that our proposed method performs better than four existing linear LCC methods according to five performance measures.","Title: Prediction of Virality Timing Using Cascades in Social Media.\nYear: 2016\n\nAbstract: Predicting content going viral in social networks is attractive for viral marketing, advertisement, entertainment, and other applications, but it remains a challenge in the big data era today. Previous works mainly focus on predicting the possible popularity of content rather than the timing of reaching such popularity. This work proposes a novel yet practical iterative algorithm to predict virality timing, in which the correlation between the timing and growth of content popularity is captured by using its own big data naturally generated from users’ sharing. Such data is not only able to correlate the dynamics and associated timings in social cascades of viral content but also can be useful to self-correct the predicted timing against the actual timing of the virality in each iterative prediction. The proposed prediction algorithm is verified by datasets from two popular social networks—Twitter and Digg—as well as two synthesized datasets with extreme network densities and infection rates. With about 50% of the required content virality data available (i.e., halfway before reaching its actual virality timing), the error of the predicted timing is proven to be bounded within a 40% deviation from the actual timing. To the best of our knowledge, this is the first work that predicts content virality timing iteratively by capturing social cascades dynamics.","Title: Symmetric Integer Matrices Having Integer Eigenvalues.\nYear: 2016\n\nAbstract: We provide characterization of symmetric integer matrices for rank at most 2 that have integer spectrum and give some constructions for such matrices of rank 3. We also make some connection between Hanlon’s conjecture and integer eigenvalue problem.","Title: Complex singular value decomposition based stereoscopic image quality assessment\nYear: 2016\n\nAbstract: Designing a reliable and generic perceptual quality metric is a challenging issue in three-dimensional (3D) visual signal processing. Due to the limited knowledge on 3D perceptual, it is difficult to fuse the visual information of left and right views in an effective way. In this paper, we propose a complex singular value decomposition (CSVD) based stereoscopic image quality assessment (SIQA) metric. First, the corresponding blocks of the left/right view are grouped into complex representation (CR) block through the scale-invariant feature transform (SIFT) view matching process. Then we compute the CSVD coefficients of each CR block. Final, a CSVD based quality pooling stage is employed to predict the final visual quality of the distorted 3D image. Experimental results demonstrate that the proposed metric has good consistency with 3D perception of human.","Title: Outlier Detection over Massive-Scale Trajectory Streams.\nYear: 2017\n\nAbstract: The detection of abnormal moving objects over high-volume trajectory streams is critical for real-time applications ranging from military surveillance to transportation management. Yet this outlier detection problem, especially along both the spatial and temporal dimensions, remains largely unexplored. In this work, we propose a rich taxonomy of novel classes of neighbor-based trajectory outlier definitions that model the anomalous behavior of moving objects for a large range of real-time applications. Our theoretical analysis and empirical study on two real-world datasets—the Beijing Taxi trajectory data and the Ground Moving Target Indicator data stream—and one generated Moving Objects dataset demonstrate the effectiveness of our taxonomy in effectively capturing different types of abnormal moving objects. Furthermore, we propose a general strategy for efficiently detecting these new outlier classes called the <underline>m</underline>inimal <underline>ex</underline>amination (MEX) framework. The MEX framework features three core optimization principles, which leverage spatiotemporal as well as the predictability properties of the neighbor evidence to minimize the detection costs. Based on this foundation, we design algorithms that detect the outliers based on these classes of new outlier semantics that successfully leverage our optimization principles. Our comprehensive experimental study demonstrates that our proposed MEX strategy drives the detection costs 100-fold down into the practical realm for applications that analyze high-volume trajectory streams in near real time.","Title: Discovering Evolving Moving Object Groups from Massive-Scale Trajectory Streams\nYear: 2017\n\nAbstract: The increasing pervasiveness of object tracking technologies leads to huge volumes of spatio-temporal data collected in the form of trajectory streams. The discovery of useful group patterns from moving objects' movement behaviors in trajectory streams is critical for real time applications ranging from transportation management to military surveillance. In this work we propose a novel type of group pattern, called evolving group, which models the unusual group events of moving objects that travel together within density connected clusters in evolving streaming trajectories. Our theoretical analysis and empirical study on the Beijing Taxi data demonstrate its effectiveness in capturing development, evolution and trend of group events of moving objects in streaming context. Furthermore, we propose a discovery framework that efficiently supports online detection of evolving groups over massive-scale trajectory streams using sliding window. It contains three phases along with a set of novel optimization techniques designed to minimize the computation costs. Our comprehensive empirical study demonstrates that our discovery framework is effective and efficient on real-world high volume trajectory streams.","Title: Soft-decision based distributed detection over correlated sensing channels\nYear: 2017\n\nAbstract: This paper proposes a new framework that performs spectrum sensing in soft decision based distributed detection systems while considering correlated sensors' readings. The main contribution is formulating the problem into a nonlinear integer programming problem for which the genetic algorithm is further applied to find a suboptimal solution. This framework is able to handle both soft and hard decisions while assuming correlation for any number of sensors, and hence largely extends the scenarios being considered in previous works. The results show that our scheme outperforms previous schemes and approaches the centralized detection scheme performance in terms of probability of error.","Title: To share or not to share: comparing burst buffer architectures\nYear: 2017\n\nAbstract: Modern high performance computing platforms employ burst buffers to overcome the I/O bottleneck that limits the scale and efficiency of large-scale parallel computations. Currently there are two competing burst buffer architectures. One is to treat burst buffers as a dedicated shared resource, The other is to integrate burst buffer hardware into each compute node. In this paper we examine the design tradeoffs associated with local and shared, dedicated burst buffer architectures through modeling. By seeding our simulation with realistic workloads, we are able to systematically evaluate the resulting performance of both designs. Our studies validate previous results indicating that storage systems without parity protection can reduce overall time to solution, and further determine that shared burst buffer organizations can result in a 3.5× greater average application I/O throughput compared to local burst buffer configurations.","Title: Distributed Local Outlier Detection in Big Data\nYear: 2017\n\nAbstract: In this work, we present the first distributed solution for the Local Outlier Factor (LOF) method -- a popular outlier detection technique shown to be very effective for datasets with skewed distributions. As datasets increase radically in size, highly scalable LOF algorithms leveraging modern distributed infrastructures are required. This poses significant challenges due to the complexity of the LOF definition, and a lack of access to the entire dataset at any individual compute machine. Our solution features a distributed LOF pipeline framework, called DLOF. Each stage of the LOF computation is conducted in a fully distributed fashion by leveraging our invariant observation for intermediate value management. Furthermore, we propose a data assignment strategy which ensures that each machine is self-sufficient in all stages of the LOF pipeline, while minimizing the number of data replicas. Based on the convergence property derived from analyzing this strategy in the context of real world datasets, we introduce a number of data-driven optimization strategies. These strategies not only minimize the computation costs within each stage, but also eliminate unnecessary communication costs by aggressively pushing the LOF computation into the early stages of the DLOF pipeline. Our comprehensive experimental study using both real and synthetic datasets confirms the efficiency and scalability of our approach to terabyte level data.","Title: Scalable Top-n Local Outlier Detection\nYear: 2017\n\nAbstract: Local Outlier Factor (LOF) method that labels all points with their respective LOF scores to indicate their status is known to be very effective for identifying outliers in datasets with a skewed distribution. Since outliers by definition are the absolute minority in a dataset, the concept of Top-N local outlier was proposed to discover the n points with the largest LOF scores. The detection of the Top-N local outliers is prohibitively expensive, since it requires huge number of high complexity k-nearest neighbor (kNN) searches. In this work, we present the first scalable Top-N local outlier detection approach called TOLF. The key innovation of TOLF is a multi-granularity pruning strategy that quickly prunes most points from the set of potential outlier candidates without computing their exact LOF scores or even without conducting any kNN search for them. Our customized density-aware indexing structure not only effectively supports the pruning strategy, but also accelerates the $k$NN search. Our extensive experimental evaluation on OpenStreetMap, SDSS, and TIGER datasets demonstrates the effectiveness of TOLF - up to 35 times faster than the state-of-the-art methods.","Title: MARAS: Signaling Multi-Drug Adverse Reactions\nYear: 2017\n\nAbstract: There is a growing need for computing-supported methods that facilitate the automated signaling of Adverse Drug Reactions (ADRs) otherwise left undiscovered from the exploding amount of ADR reports filed by patients, medical professionals and drug manufacturers. In this research, we design a Multi-Drug Adverse Reaction Analytics Strategy, called MARAS, to signal severe unknown ADRs triggered by the usage of a combination of drugs, also known as Multi-Drug Adverse Reactions (MDAR). First, MARAS features an efficient signal generation algorithm based on association rule learning that extracts non-spurious MDAR associations. Second, MARAS incorporates contextual information to detect drug combinations that are strongly associated with a set of ADRs. It groups related associations into Contextual Association Clusters (CACs) that then avail contextual information to evaluate the significance of the discovered MDAR Associations. Lastly, we use this contextual significance to rank discoveries by their notion of interestingness to signal the most compelling MDARs. To demonstrate the utility of MARAS, it is compared with state-of-the-art techniques and evaluated via case studies on datasets collected by U.S. Food and Drug Administration Adverse Event Reporting System (FAERS).","Title: NTIRE 2017 Challenge on Single Image Super-Resolution: Methods and Results.\nYear: 2018\n\nAbstract: This paper reviews the first challenge on single image super-resolution (restoration of rich details in an low resolution image) with focus on proposed solutions and results. A new DIVerse 2K resolution image dataset (DIV2K) was employed. The challenge had 6 competitions divided into 2 tracks with 3 magnification factors each. Track 1 employed the standard bicubic downscaling setup, while Track 2 had unknown downscaling operators (blur kernel and decimation) but learnable through low and high res train images. Each competition had similar to 100 registered participants and 20 teams competed in the final testing phase. They gauge the state-of-the-art in single image super-resolution.","Title: On the performance of LT codes over BIAWGN channel\nYear: 2016\n\nAbstract: Luby transform (LT) codes are defined by degree distribution functions of encoded symbols. In erasure channels, good degree distribution functions should prevent the ripple of degree-one symbols from vanishing until the successful termination of decoding process. In this paper, we show that for binary input additive white Gaussian noise (BIAWGN) channels, performance of LT codes also depends on the time at which source nodes in the decoding graph of the codes start receiving non-zero log-likelihood ratio (LLR) values. We show that source nodes can be categorized based on this time, and those in lower categories, i.e., those source nodes updated with non-zero LLR values at earlier iterations have higher probability of being decoded correctly. We theoretically derive formulas that can find the percentages of source nodes in each category for any given degree distribution function. We finally show that by increasing the number of source nodes in the lower categories, the bit error rate (BER) performance of LT codes can be drastically improved. This work provides a new perspective for the performance and design of such codes for BIAWGN channels.","Title: Improved decoding for Raptor codes with short block-lengths over BIAWGN channel\nYear: 2016\n\nAbstract: Decoding of Raptor codes consists of decoding of both the LT part and the precode part of the codes. When LT decoding is performed, a scenario may arise where the message passing-based decoding process is unable to provide non-zero log-likelihood ratio (LLR) updates to a fraction of input symbols even if it is mathematically possible to do so. The problem is even more critical for codes with short block-lengths and for smaller overheads. We show that this problem degrades the overall decoding performance of Raptor codes over binary input additive white Gaussian noise (BIAWGN) channel. To combat this problem, the Gauss-Jordan elimination (GJE) is used to assist decoding so that the decoder can continuously provide non-zero LLR updates to all the input symbols connected in the decoding graph. Through simulation results we show that the GJE-assisted method provides significantly better bit error rate (BER) performance of Raptor codes than the traditional method across a wide range of signal to noise ratio (SNR) and transmission overheads.","Title: Interactive Analytics System for Exploring Outliers.\nYear: 2017\n\nAbstract: ONION is the first system with rich interactive support for efficiently analyzing outliers. ONION features an innovative exploration model that offers an \"outlier-centric panorama'' into big datasets. The ONION system is composed of an offline preprocessing phase followed by an online exploration phase that supports rich classes of novel exploration operations. As our demonstration illustrates, this enables analysts to interactively explore outliers at near real-time speed even over large datasets. We demonstrate ONION's capabilities with urban planning applications use cases on the Open Street Maps dataset.","Title: Combined-chain nested sampling for efficient Bayesian model comparison.\nYear: 2017\n\nAbstract: Model comparison problems arise in many fields of science and engineering, including signal processing. In these problems, we wish to quantify how well each of a set of possible models describes a set of observations. Many numerical techniques exist to perform model comparison, but this paper focuses on nested sampling, which is a numerical integration algorithm for evaluating probabilities of models. The original formulation of nested sampling is a strictly sequential algorithm. Most modern advances in computing are via parallel processing, however, and we therefore present a novel method for parallelizing nested sampling. This paper sets out the mathematical foundation for this parallelization, as well as ideas for implementing it. Three examples demonstrate the effectiveness of the present parallel technique in realistic scientific and engineering data analysis problems.","Title: A Study Of Qualitative Knowledge-Based Exploration For Continuous Deep Reinforcement Learning\nYear: 2017\n\nAbstract: As an important method to solve sequential decision-making problems, reinforcement learning learns the policy of tasks through the interaction with environment. But it has difficulties scaling to large-scale problems. One of the reasons is the exploration and exploitation dilemma which may lead to inefficient learning. We present an approach that addresses this shortcoming by introducing qualitative knowledge into reinforcement learning using cloud control systems to represent 'if-then' rules. We use it as the heuristics exploration strategy to guide the action selection in deep reinforcement learning. Empirical evaluation results show that our approach can make significant improvement in the learning process.","Title: Pivot-Based Distributed K-Nearest Neighbor Mining.\nYear: 2017\n\nAbstract: k-nearest neighbor (kNN) search is a fundamental data mining task critical to many data analytics methods. Yet no effective techniques to date scale kNN search to large datasets. In this work we present PkNN, an exact distributed method that by leveraging modern distributed architectures for the first time scales kNN search to billion point datasets. The key to the PkNN strategy is a multi-round kNN search that exploits pivot-based data partitioning at each stage. This includes an outlier-driven partition adjustment mechanism that effectively minimizes data duplication and achieves a balanced workload across the compute cluster. Aggressive data-driven bounds along with a tiered support assignment strategy ensure correctness while limiting computation costs. Our experimental study on multi-dimensional real-world data demonstrates that PkNN achieves significant speedup over the state-of-the-art and scales effectively in data cardinality. Code and data related to this chapter are available at: http://solar-10.wpi.edu/cakuhlman/ PkNN.","Title: Protocol Design for Content Transfer in Deep Space Network.\nYear: 2017\n\nAbstract: Space communications feature large round-trip time (RTT) delays and highly variable data error rates. In this paper, we propose a new content transfer protocol based on RaptorQ codes and turbo codes, incorporated with a real-time channel prediction model, to maximize file transfer from space vehicles to Earth stations. While turbo codes are used to correct channel errors, RaptorQ codes are applied to eliminate the need for negative-acknowledgment (NAK) of the loss of any specific packet. To reduce the effect of channel variation, a practical signal-to-noise ratio (SNR) prediction model that is used to periodically adjust the turbo encoder in distant source spacecraft is developed. This new protocol, termed as the dynamic code selection method (DCSM), is compared with two other methods: a turbo codes based genie method (upper bound of DCSM performance) assuming that the channel condition is perfectly known in advance and a static method in which a fixed turbo encoder is used throughout each communication pass. Simulation results demonstrate that the genie and the new DCSM methods can increase telemetry channel throughput by about 47% and 46%, respectively, compared to the static method. In addition, throughput performance using the DCSM is about 99% of the upper bound achieved with the genie method.","Title: Study Of Subjective And Objective Quality Assessment For Screen Content Images\nYear: 2017\n\nAbstract: In this paper, we present the results of a recent large-scale subjective study of image quality on a collection of screen contents distorted by a variety of application-relevant processes. With the development of multi-device interactive multimedia applications, metrics to predict the visual quality of screen content images (SCIs) as perceived by subjects are becoming fundamentally important. For developing the objective image quality assessment (IQA) method, there is a need for large-scale public database with diversity of distorted types and scene contents, and available subjective scores of distorted SCIs. The resulting Immersive Media Laboratory screen content image quality database (IML-SCIQD) contains 1250 distorted SCIs from 25 reference SCIs with 10 distortion types. Each image was rated by 35 human observers, and the different mean opinion scores (DMOS) were obtained after data processing. The performance comparison of 17 state-of-the-arts, publicly available IQA algorithms are evaluated on the new database. The database will be available online in our project website.","Title: On the Design of Serially Concatenated LDGM Codes for BIAWGN Channels.\nYear: 2018\n\nAbstract: In this paper, we first prove a necessary condition for the successful decoding of serially concatenated low-density generator-matrix (SCLDGM) codes under sum-product (SP) decoding in binary input additive white Gaussian noise (BIAWGN) channels. We show that the inner decoder of such codes must at least produce a certain bit error rate (BER) called critical BER in order for the outer decoder to achieve successful decoding. We verify this condition by providing asymptotic curves for the SCLDGM codes using discretized density evolution (DDE) method. We finally propose a DDE-based optimization approach that utilizes the concept of the critical BER to construct optimized SCLDGM codes that approach the Shannon limit. We also present asymptotic and simulation results of our optimized codes that verify the effectiveness of the proposed optimization approach.","Title: Asymptotic analysis and optimization design of physical layer systematic rateless codes\nYear: 2018\n\nAbstract: In this paper, we first provide the asymptotic analysis of systematic version of Luby transform (LT) and Raptor codes over binary input additive white Gaussian noise (BIAWGN) channel using discretized density evolution (DDE). We then use a DDE-based optimization approach to obtain optimized output degree distributions for the systematic Raptor (SR) codes of various realized code-rates. We finally provide the decoding thresholds and simulation results showing that our optimized SR codes largely outperform the traditional SR codes in BIAWGN channel.","Title: How to foster innovation: A data-driven approach to measuring economic competitiveness.\nYear: 2017\n\nAbstract: Innovation is a key factor driving economic growth in countries worldwide. However, innovation is hard to define and, therefore, even harder to measure. To help policy makers and business leaders better understand how to foster innovation, we need robust ways to quantify innovation at local and global scales. In this work, we use a data-driven, machine-learning approach for measuring innovation. A...","Title: Analysis and Design of Physical Layer Raptor Codes.\nYear: 2018\n\nAbstract: In this letter, we first provide the asymptotic analysis of Raptor codes over binary input additive white Gaussian noise channels using discretized density evolution (DDE). We show that the Raptor codes of various realized code-rates using the same output degree distribution perform within 0.4-dB to the Shannon limit. We then prove a necessary condition for the successful decoding of such codes and use it with a DDE-based optimization method to obtain optimized Raptor codes with further improvement in decoding thresholds.","Title: Optimal Channel Set Selection For Ssvep-Based Bci Using Spatial Temporal Correlation\nYear: 2017\n\nAbstract: In SSVEP-based BCI, portability has great influence on the popularization. Reducing redundant channels is an effective way to upgrade the portability. This paper presents a novel method that utilizes spatial temporal correlation (STC) to optimize the selection of channel set. Average accuracy was obtained at 85.28% using STC, improved by 1.11%, proving that STC method is effective to find out the most useful channels in detecting SSVEP components. And the optimal set, chosen by STC, yield an average accuracy at 83.34%, means that STC can help BCI improve the convenience by reducing the number of channels without shrinking the performance sharply and provide guidance for further SSVEP-based BCI.","Title: Fiber Bragg Grating-Based Triaxial Force Sensor With Parallel Flexure Hinges.\nYear: 2018\n\nAbstract: During cardiac surgery, the excessive or insufficient contact force between the tip of catheter and heart tissue will lead to the cardiac penetration or noneffective ablative lesion. Usually, the surgeon can only estimate the force at the distal end roughly from their experience by operating the catheter's proximal handle. In this paper, we design a fiber Bragg grating-based triaxial force sensor ...","Title: Short time Fourier transformation and deep neural networks for motor imagery brain computer interface recognition.\nYear: 2018\n\nAbstract: Motor imagery (MI) is an important control paradigm in the field of brain-computer interface (BCI), which enables the recognition of personal intention. So far, numerous methods have been designed to classify EEG signal features for MI task. However, deep neural networks have been seldom applied to analyze EEG signals. In this study, two novel kinds of deep learning schemes based on convolutional neural networks (CNN) and Long Short-Term Memory (LSTM) were proposed for MI-classification. The frequency domain representations of EEG signals were obtained using short time Fourier transform (STFT) to train models. Classification results were compared between conventional algorithm, CNN, and LSTM models. Compared with two other methods, CNN algorithms had shown better performance. These conclusions verified that CNN method was promising for MI-based BCIs.","Title: Infrared Small Target Detection Based on Flux Density and Direction Diversity in Gradient Vector Field.\nYear: 2018\n\nAbstract: The existing small target detection methods may suffer serious false alarm rate and low probability of detection in the situation of intricate background clutter. To cope with this problem, a novel small target detection method is proposed in this paper. Initially, the infrared image is transformed to the infrared gradient vector field (IGVF), where some new distinctive characters of the target an...","Title: SWIFT: Mining Representative Patterns from Large Event Streams.\nYear: 2018\n\nAbstract: Event streams generated by smart devices common in modern Internet of Things applications must be continuously mined to monitor the behavior of the underlying system. In this work, we propose a stream pattern mining system for supporting online IoT applications. First, to solve the pattern explosion problem of existing stream pattern mining strategies, we now design pattern semantics that continuously produce a compact set of patterns that max-imumly compresses the dynamic data streams, called MDL-based Representative Patterns (MRP). We then design a one-pass SWIFT approach that continuously mines the up-to-date MRP pattern set for each stream window upon the arrival or expiration of individual events. We show that SWIFT is guaranteed to select the update operation for each individual incoming event that leads to the most compact encoding of the sequence in the current window. We further enhance SWIFT to support batch updates, called B-SWIFT. B-SWIFT adopts a lazy update strategy that guarantees that only the minimal number of operations are conducted to process an incoming event batch for MRP pattern mining. Evaluation by our industry lighting lab collaborator demonstrates that SWIFT successfully solves their use cases and finds more representative patterns than the alternative approaches adapting the state-of-the-art static representative pattern mining methods. Our experimental study confirms that SWIFT outperforms the best existing method up to 50% in the compactness of produced pattern encodings, while providing a 4 orders of magnitude speedup.","Title: Decentralized Detection of Signals with Joint Clayton Copula Distribution Model\nYear: 2018\n\nAbstract: This paper considers a decentralized detection system for a binary hypothesis testing problem. The sensor signals are marginally Gaussian distributed with θ-parameter Clayton copula joint distribution. Boolean functions of two variables and likelihood ratio test at the fusion center are considered to generate binary global decisions. The exhaustive search and the genetic algorithms are proposed to provide the local sensor decision rules in each scenario such that the probability of error at the fusion center is minimized. The main purpose of this paper is to study the probability of error behavior of the proposed detection systems in a correlated environment characterized by a joint Clayton copula distribution. The results show that in a correlated environment a sound detection system should be characterized by the likelihood ratio test at the fusion center and multiple-threshold decisions at the sensors.","Title: Blind channel estimation and equalization using Viterbi algorithms\nYear: 2002\n\nAbstract: In this paper, a trellis based blind channel estimation and equalization technique is presented. First, blind channel estimation is accomplished by incorporating a list parallel Viterbi algorithm with the least mean square (LMS) updating approach. In this operation, multiple trellis mappings are preserved and ranked in terms of path metrics. Equivalently, multiple channel estimates are maintained and updated once a single symbol is received. Second, at a certain point, which is determined by the evolution of path metrics and the linear constraint possessed in the trellis mapping, only the best channel estimate is maintained. Third, this channel estimate is adopted to construct the whole trellis that is used by a conventional adaptive Viterbi algorithm. Signal detection and further channel updating are then conducted alternatively. To alleviate the noise impact, a small delay is introduced before the feedback of detected symbols to further update the channel estimate. Simulation has shown the overall good performance of the proposed scheme in terms of mean square error (MSE) convergence of the channel estimation, stability to the initial channel guess, and computational complexity etc.","Title: Planning enhanced grid workflow management system based on agent\nYear: 2005\n\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is emerging as one of the most important grid services. In this paper, we present a planning enhanced grid workflow management system based on agent (AGWMS). AGWMS has a four-layer architecture. The agent layer makes the system more robust, flexible and intelligent. Artificial intelligence (AI) planning technology is utilized in the system to build the agent plans automatically. The adapter layer makes it easy that AGWMS invokes external applications. Our planning enhanced AGWMS is a novel one.","Title: Noise Correlation Effect on Detection: Signals in Equicorrelated or Autoregressive(1) Gaussian.\nYear: 2017\n\nAbstract: In this letter, we consider the effect of noise correlation on the error performance of binary hypothesis signal detection, when one of two deterministic signals is received in correlated Gaussian noise. For the likelihood ratio detection scheme, analytical performance results are derived for equicorrelated and autoregressive order one models. Although it is known previously that the best signal l...","Title: An Optimized Algorithm for Calculating the Average Path Length of Complex Network\nYear: 2017\n\nAbstract: To calculate the average path length of a large-scale complex network accurately and efficiently is always an important topic in the study of complex networks. For this purpose, an optimized algorithm is proposed based on reachability matrix as well as its efficiency analysis. The basic idea of this algorithm is to construct network distance matrix through network reachability matrix firstly, then to calculate the average path length according to distance matrix. It is proved and verified that the proposed algorithm is much more efficient than traditional algorithms like Floyd and Warshall algorithms for calculating large-scale complex networks with small-world effect.","Title: Deep Reinforcement Learning With Sarsa And Q-Learning: A Hybrid Approach\nYear: 2018\n\nAbstract: The commonly used Deep Q Networks is known to overestimate action values under certain conditions. It's also proved that overestimations do harm to performance, which might cause instability and divergence of learning. In this paper, we present the Deep Sarsa and Q Networks (DSQN) algorithm, which can considered as an enhancement to the Deep Q Networks algorithm. First, DSQN algorithm takes advantage of the experience replay and target network techniques in Deep Q Networks to improve the stability of neural networks. Second, double estimator is utilized for Q-learning to reduce overestimations. Especially, we introduce Sarsa learning to Deep Q Networks for removing overestimations further. Finally, DSQN algorithm is evaluated on cart-pole balancing, mountain car and lunarlander control task from the OpenAI Gym. The empirical evaluation results show that the proposed method leads to reduced overestimations, more stable learning process and improved performance.","Title: Automatic Segmentation of Pathological Glomerular Basement Membrane in Transmission Electron Microscopy Images with Random Forest Stacks.\nYear: 2019\n\nAbstract: Pathological classification through transmission electron microscopy (TEM) is essential for the diagnosis of certain nephropathy, and the changes of thickness in glomerular basement membrane (GBM) and presence of immune complex deposits in GBM are often used as diagnostic criteria. The automatic segmentation of the GBM on TEM images by computerized technology can provide clinicians with clear information about glomerular ultrastructural lesions. The GBM region on the TEM image is not only complicated and changeable in shape but also has a low contrast and wide distribution of grayscale. Consequently, extracting image features and obtaining excellent segmentation results are difficult. To address this problem, we introduce a random forest- (RF-) based machine learning method, namely, RF stacks (RFS), to realize automatic segmentation. Specifically, this work proposes a two-level integrated RFS that is more complicated than a one-level integrated RF to improve accuracy and generalization performance. The integrated strategies include training integration and testing integration. Training integration can derive a full-view RFS1 by simultaneously sampling several images of different grayscale ranges in the train phase. Testing integration can derive a zoom-view RFS2 by separately sampling the images of different grayscale ranges and integrating the results in the test phase. Experimental results illustrate that the proposed RFS can be used to automatically segment different morphologies and gray-level basement membranes. Future study on GBM thickness measurement and deposit identification will be based on this work.","Title: Discrete-time sliding mode control for a class of nonlinear process\nYear: 2020\n\nAbstract: The efficient control of nonlinear processes is generally considered to be challenging. The development of digital computers promotes the study of nonlinear process control technology. Due to the discrete sampling of digital computer, it is necessary to develop the corresponding control algorithms for nonlinear processes. In this paper, a new equivalent control-based discrete-time sliding mode control is proposed for a class of nonlinear process with uncertainty and external disturbance. An adaptive law and a disturbance observer are designed to estimate the uncertainty and the disturbance, respectively. By combining with them, the new discrete-time sliding mode control is developed with good performance. The corresponding theoretical analysis is well verified by using Lyapunov function. Finally, the proposed approach is demonstrated by case studies in light of MATLAB.","Title: Learning to Learn: Hierarchical Meta-Critic Networks\nYear: 2019\n\nAbstract: In recent years, deep reinforcement learning methods have achieved impressive performance in many different fields, including playing games, robotics, and dialogue systems. However, there are still a lot of restrictions here, one of which is the demand for massive amounts of sampled data. In this paper, a hierarchical meta-learning method based on the actor-critic algorithm is proposed for sample efficient learning. This method provides the transferable knowledge that can efficiently train an actor on a new task with a few trials. Specifically, a global basic critic, meta critic, and task specified network are shared within a distribution of tasks and are capable of criticizing any actor trying to solve any specified task. The hierarchical framework is applied to a critic network in the actor-critic algorithm for distilling meta-knowledge above the task level and addressing distinct tasks. The proposed method is evaluated on multiple classic control tasks with reinforcement learning algorithms, including the start-of-the-art meta-learning methods. The experimental results statistically demonstrate that the proposed method achieves state-of-the-art performance and attains better results with more depth of meta critic network.","Title: Soft-Decision-Based Distributed Detection With Correlated Sensing Channels.\nYear: 2019\n\nAbstract: Prior works on distributed detection with correlated Gaussian observations primarily dealt with single-bit reports to the fusion center and suboptimal fusion rules. Considering multiple bits and independent reporting channel errors, we formulate the optimal detection problem as a nonlinear integer programming problem for which the genetic algorithm is applied to find a suboptimal solution. The Bay...","Title: Efficient discovery of sequence outlier patterns\nYear: 2019\n\nAbstract: Modern Internet of Things (IoT) applications generate massive amounts of time-stamped data, much of it in the form of discrete, symbolic sequences. In this work, we present a new system called TOP that de<u>T</u>ects <u>O</u>utlier <u>P</u>atterns from these sequences. To solve the fundamental limitation of existing pattern mining semantics that miss outlier patterns hidden inside of larger frequent patterns, TOP offers new pattern semantics based on contextual patterns that distinguish the independent occurrence of a pattern from its occurrence as part of its super-pattern. We present efficient algorithms for the mining of this new class of contextual patterns. In particular, in contrast to the bottom-up strategy for state-of-the-art pattern mining techniques, our top-down Reduce strategy piggy backs pattern detection with the detection of the context in which a pattern occurs. Our approach achieves linear time complexity in the length of the input sequence. Effective optimization techniques such as context-driven search space pruning and inverted index-based outlier pattern detection are also proposed to further speed up contextual pattern mining. Our experimental evaluation demonstrates the effectiveness of TOP at capturing meaningful outlier patterns in several real-world IoT use cases. We also demonstrate the efficiency of TOP, showing it to be up to 2 orders of magnitude faster than adapting state-of-the-art mining to produce this new class of contextual outlier patterns, allowing us to scale outlier pattern mining to large sequence datasets.","Title: A novel attention-guided convolutional network for the detection of abnormal cervical cells in cervical cancer screening\nYear: 2021\n\nAbstract: •A novel attention-guided deep learning method to aid in cervical cancer screening.•Attention module to mimic the way pathologist reading a cervical cytology image in clinical workflow.•Preparing a dataset of around 70,552 cervical cytology images for abnormal cervical cell detection.•Comparing the performance of our method with the other related deep learning methods as well as human pathologists.•Results better than the other deep learning methods and comparable to human pathologists with 10-year experience.","Title: Category-Aware Chronic Stress Detection on Microblogs\nYear: 2022\n\nAbstract: People today live a stressful life. Compared with acute stress, long-term chronic stress is more harmful, and may cause or exacerbate many serious health problems, including high blood pressure, heart disease, chronic pain, and mental diseases. With social media becoming an integral part of our daily lives for information sharing and self-expression, detecting category-aware long-standing chronic stress from a large volume of historic open posts made by social media users is possible. In this study, we construct a data set containing 971 chronically stressed users with totally 54 546 open posts on Sina microblog from July 5, 2018 to December 1, 2019, and design two techniques for category-aware chronic stress detection: (1) a stress-oriented word embedding on the basis of an existing pre-trained word embedding, aiming to strengthen the sensibility of stress-related expressions for linguistic post analysis; (2) a multi-attention model with three layers (i.e., category-attention layer, posts self-attention layer, and category-specific post attention layer), aiming to capture inter-relevance from a sequence of posts and infer long-term stress categories and stress levels. The experimental results show that the proposed multi-attention model equipped with the stress-oriented word embedding can achieve 80.65% accuracy in detecting category-aware stress levels, 86.49% accuracy in detecting chronic stress levels only, and 93.07% accuracy in detecting chronic stress categories only. Limitations and implications of the study are also discussed at the end of the paper.","Title: AI Meets Database: AI4DB and DB4AI\nYear: 2021\n\nAbstract: ABSTRACTDatabase and Artificial Intelligence (AI) can benefit from each other. On one hand, AI can make database more intelligent (AI4DB). For example, traditional empirical database optimization techniques (e.g., cost estimation, join order selection, knob tuning, index and view advisor) cannot meet the high-performance requirement for large-scale database instances, various applications and diversified users, especially on the cloud. Fortunately, learning-based techniques can alleviate this problem. On the other hand, database techniques can optimize AI models (DB4AI). For example, AI is hard to deploy, because it requires developers to write complex codes and train complicated models. Database techniques can be used to reduce the complexity of using AI models, accelerate AI algorithms and provide AI capability inside databases. DB4AI and AI4DB have been extensively studied recently. In this tutorial, we review existing studies on AI4DB and DB4AI. For AI4DB, we review the techniques on learning-based database configuration, optimization, design, monitoring, and security. For DB4AI, we review AI-oriented declarative language, data governance, training acceleration, and inference acceleration. Finally, we provide research challenges and future directions in AI4DB and DB4AI.","Title: ELITE: Robust Deep Anomaly Detection with Meta Gradient\nYear: 2021\n\nAbstract: ABSTRACTDeep Learning techniques have been widely used in detecting anomalies from complex data. Most of these techniques are either unsupervised or semi-supervised because of a lack of a large number of labeled anomalies. However, they typically rely on a clean training data not polluted by anomalies to learn the distribution of the normal data. Otherwise, the learned distribution tends to be distorted and hence ineffective in distinguishing between normal and abnormal data. To solve this problem, we propose a novel approach called ELITE that uses a small number of labeled examples to infer the anomalies hidden in the training samples. It then turns these anomalies into useful signals that help to better detect anomalies from user data. Unlike the classical semi-supervised classification strategy which uses labeled examples as training data, ELITE uses them as validation set. It leverages the gradient of the validation loss to predict if one training sample is abnormal. The intuition is that correctly identifying the hidden anomalies could produce a better deep anomaly model with reduced validation loss. Our experiments on public benchmark datasets show that ELITE achieves up to 30% improvement in ROC AUC comparing to the state-of-the-art, yet robust to polluted training data.","Title: Bionic Birdlike Imaging Using A Multi-Hyperuniform Led Array\nYear: 2021\n\nAbstract: Digital cameras obtain color information of the scene using a chromatic filter, usually a Bayer filter, overlaid on a pixelated detector. However, the periodic arrangement of both the filter array and the detector array introduces frequency aliasing in sampling and color misregistration during demosaicking process which causes degradation of image quality. Inspired by the biological structure of the avian retinas, we developed a chromatic LED array which has a geometric arrangement of multi-hyperuniformity, which exhibits an irregularity on small-length scales but a quasi-uniformity on large scales, to suppress frequency aliasing and color misregistration in full color image retrieval. Experiments were performed with a single-pixel imaging system using the multi-hyperuniform chromatic LED array to provide structured illumination, and 208 fps frame rate was achieved at 32 x 32 pixel resolution. By comparing the experimental results with the images captured with a conventional digital camera, it has been demonstrated that the proposed imaging system forms images with less chromatic moire patterns and color misregistration artifacts. The concept proposed verified here could provide insights for the design and the manufacturing of future bionic imaging sensors.","Title: LANCET: labeling complex data at scale\nYear: 2021\n\nAbstract: AbstractCutting-edge machine learning techniques often require millions of labeled data objects to train a robust model. Because relying on humans to supply such a huge number of labels is rarely practical, automated methods for label generation are needed. Unfortunately, critical challenges in auto-labeling remain unsolved, including the following research questions: (1) which objects to ask humans to label, (2) how to automatically propagate labels to other objects, and (3) when to stop labeling. These three questions are not only each challenging in their own right, but they also correspond to tightly interdependent problems. Yet existing techniques provide at best isolated solutions to a subset of these challenges. In this work, we propose the first approach, called LANCET, that successfully addresses all three challenges in an integrated framework. LANCET is based on a theoretical foundation characterizing the properties that the labeled dataset must satisfy to train an effective prediction model, namely the Covariate-shift and the Continuity conditions. First, guided by the Covariate-shift condition, LANCET maps raw input data into a semantic feature space, where an unlabeled object is expected to share the same label with its near-by labeled neighbor. Next, guided by the Continuity condition, LANCET selects objects for labeling, aiming to ensure that unlabeled objects always have some sufficiently close labeled neighbors. These two strategies jointly maximize the accuracy of the automatically produced labels and the prediction accuracy of the machine learning models trained on these labels. Lastly, LANCET uses a distribution matching network to verify whether both the Covariate-shift and Continuity conditions hold, in which case it would be safe to terminate the labeling process. Our experiments on diverse public data sets demonstrate that LANCET consistently outperforms the state-of-the-art methods from Snuba to GOGGLES and other baselines by a large margin - up to 30 percentage points increase in accuracy.","Title: ATLANTIC: making database differentially private and faster with accuracy guarantee\nYear: 2021\n\nAbstract: AbstractDifferential privacy promises to enable data sharing and general data analytics while protecting individual privacy. Because the private data is often stored in the form of relational database that supports SQL queries, making SQL-based analytics differentially private is thus critical. However, the existing SQL-based differentially private systems either only focus on specific type of SQL queries such as COUNT or substantially modify the database engine, thus obstructing adoption in practice. Worse yet, these systems often do not guarantee the desired accuracy by the applications. In this demonstration, using the driving trace workload from Cambridge Mobile Telematics (CMT), we show that our ATLANTIC system, as a database middleware, enforces differential privacy for real-world SQL queries with provable accuracy guarantees and is compatible with existing databases. Moreover, using a sampling-based technique, ATLANTIC significantly speeds up the query execution, yet effectively amplifying the privacy guarantee.","Title: Machine learning for databases\nYear: 2021\n\nAbstract: AbstractMachine learning techniques have been proposed to optimize the databases. For example, traditional empirical database optimization techniques (e.g., cost estimation, join order selection, knob tuning, index and view advisor) cannot meet the high-performance requirement for large-scale database instances, various applications and diversified users, especially on the cloud. Fortunately, machine learning based techniques can alleviate this problem by judiciously selecting optimization strategy. In this tutorial, we categorize database tasks into three typical problems that can be optimized by different machine learning models, including NP-hard problems (e.g., knob space exploration, index/view selection, partition-key recommendation for offline optimization; query rewrite, join order selection for online optimization), regression problems (e.g., cost/cardinality estimation, index/view benefit estimation, query latency prediction), and prediction problems (e.g., query workload prediction). We review existing machine learning based techniques to address these problems and provide research challenges.","Title: Pattern-Avoiding (0,1)-Matrices And Bases Of Permutation Matrices\nYear: 2021\n\nAbstract: We investigate pattern-avoiding n x n (0, 1)-matrices with emphasis on patterns of length 3: pqr-avoiding where {p, q, r} subset of {1, 2,..., n}. We show that all such maximal (0, 1)-matrices contain the same number of 1's, and their structure is determined. We then show that the set of pqr-avoiding nxn permutation matrices span the linear space of dimension (n - 1)(2) + 1 generated by the n x n permutation matrices and determine a corresponding basis for each p, q, r. (c) 2021 Elsevier B.V. All rights reserved.","Title: Combining Tracking and Remote Sensing to Identify Critical Year-Round Site, Habitat Use and Migratory Connectivity of a Threatened Waterbird Species\nYear: 2021\n\nAbstract: We tracked 39 western flyway white-naped cranes (Antigone vipio) throughout multiple annual cycles from June 2017 to July 2020, using GSM-GPS loggers providing positions every 10-min to describe migration routes and key staging areas used between their Mongolian breeding and wintering areas in China's Yangtze River Basin. The results demonstrated that white-naped cranes migrated an average of 2556 km (& PLUSMN;187.9 SD) in autumn and 2673 km (& PLUSMN;342.3) in spring. We identified 86 critical stopover sites that supported individuals for more than 14 days, within a 100-800 km wide migratory corridor. This study also confirmed that Luan River catchment is the most important staging region, where white-naped cranes spent 18% of the annual cycle (in both spring and autumn) each year. Throughout the annual cycle, 69% of the tracking locations were from outside of the currently protected areas, while none of the critical staging areas enjoyed any form of site protection. We see further future potential to combine avian tracking data and remote-sensing information throughout the annual range of the white-naped crane to restore it and other such species to a more favourable conservation status.</p>","Title: Distributed Top-N Local Outlier Detection In Big Data\nYear: 2017\n\nAbstract: The concept of Top-N local outlier that focuses on the detection of the N points with the largest Local Outlier Factor (LOF) score has been shown to be very effective for identifying outliers in big datasets. However, detecting Top-N local outliers is computationally expensive, since the computation of LOF scores for all data points requires a huge number of high complexity k-nearest neighbor (kNN) searches. In this work, we thus present the first distributed solution to tackle this problem of Top-N local outlier detection (DTOLF). First, DTOLF features an innovative safe elimination strategy that efficiently identifies dually-safe points, namely those that are guaranteed to (1) not be classified as Top-N outliers and (2) not be needed as neighbors of points residing on other machines. Therefore, it effectively minimizes both the processing and communication costs of the Top-N outlier detection process. Further, based on the well-accepted observation that strong correlations among attributes are prevalent in real world datasets, we propose correlation-aware optimization strategies that ensure the effectiveness of grid-based partitioning and of the safe elimination strategy in multi-dimensional datasets. Our extensive experimental evaluation on OpenStreetMap, SDSS, and TIGER datasets demonstrates the effectiveness of DTOLF - up to 10 times faster than the alternative methods and scaling to terabyte level datasets.","Title: A multipopulation evolutionary framework with Steffensen's method for dynamic multiobjective optimization problems\nYear: 2021\n\nAbstract: Dynamic multiobjective optimization problems (DMOPs) require the evolutionary algorithms that can track the moving Pareto-optimal fronts efficiently. This paper presents a dynamic multiobjective evolutionary framework (DMOEF-MS), which adopts a novel multipopulation structure and Steffensen's method to solve DMOPs. In DMOEF-MS, only one population deals with the original DMOP, while the others focus on single-objective problems that are generated by the weighted summation of the original DMOP. Then, Steffensen's method is used to control the evolving process in two ways: prediction and diversity-maintenance. Particularly, the prediction strategy is devised to predict the next promising positions for the individuals that handle single-objective problems, and the diversity-maintenance strategy is used to increase population diversity before the environment changes and reinitialize the multiple populations after the environment changes. This paper gives a comprehensive comparison of DMOEF-MS with some state-of-the-art DMOEAs on 14 DMOPs and the experimental results demonstrate the effectiveness of the proposed algorithm.","Title: Optimal Sensor Power Allocation for Decentralized Detection in Power Constrained Wireless Sensor Networks\nYear: 2021\n\nAbstract: We consider a distributed detection network where several sensors amplify and forward their local observations over parallel access channels (PAC) to a fusion center (FC) in order to detect the presence or absence of a deterministic signal in Gaussian noise. Two observation models are studied: i) conditionally independent observations and ii) conditionally correlated observations obeying first-ord...","Title: Detection Performance Comparison of Two-Sensor Parallel and Tandem Distributed Detection Networks\nYear: 2021\n\nAbstract: For detecting deterministic signals corrupted by correlated Gaussian noise in a two-sensor distributed detection network, we study and compare the detection performance of the parallel topology with the tandem topology. It is known that under certain conditions, optimum sensor rules are in the form of single-threshold in both topologies. In other cases, by formulating the distributed detection pro...","Title: Fair Coexistence of LAA and WiFi in Multi-Carrier LBT based on Joint Throughput and Airtime Fairness\nYear: 2021\n\nAbstract: LAA-LBT is a sensing-based access mechanism for spectrum sharing which allows the harmonious coexistence of LTE with incumbents such as WiFi in the unlicensed band. The contention window size for random backoff for LBT procedure plays a significant role in determining the throughput, airtime and fair allocation of resources between stations contending on multiple channels. This paper focuses on fa...","Title: Recurrent spiking neural network with dynamic presynaptic currents based on backpropagation\nYear: 2022\n\nAbstract: In recent years, spiking neural networks (SNNs), which originated from the theoretical basis of neuroscience, have attracted neuromorphic computing and brain-like computing due to their advantages, such as neural dynamics and coding mechanism, which are similar to biological neurons. SNNs have become one of the mainstream frameworks in the field of brain-like computing. However, most of the Leaky Integrate-and-Fire (LIF) neuron models currently used by SNNs based on direct training of backpropagation (BP) do not consider the changes in the recurrent connections and the dynamic strength of neuron connections over time. This study presented the LIF neuron model with recurrent connections and a method for dynamically changing the presynaptic currents. Recurrent LIF neurons have an additional cyclic connection compared with classic LIF neurons. Their postsynaptic current stimulates a change in membrane potential at the next time point. Their dynamics were more similar to the activities of biological neurons. We also proposed an efficient and flexible BP training method for recurrent LIF neurons. On the basis of the above methods, we proposed the recurrent SNN with dynamic presynaptic currents based on backpropagation (RDS-BP). We test the proposed RDS-BP on three image data sets (MNIST, Fashion-MNIST and CIFAR-10) and two text data sets (IMDB and TREC). The results showed that the performance of RDS-BP not only exceeded the naive SNN models based on BP but also exceeded the SNN methods proposed in previous studies in recent years, which had excellent performance in previous experiments. Our work provides a new LIF neuron model with a recurrent connection and dynamic presynaptic current and a BP training arrangement for the proposed neuron, which could merit developments with neuromorphic and brain-like computing.","Title: Scalable Motif Counting for Large-scale Temporal Graphs\nYear: 2022\n\nAbstract: One fundamental problem in temporal graph analysis is to count the occurrences of small connected subgraph patterns (i.e., motifs), which benefits a broad range of real-world applications, such as anomaly detection, structure prediction, and network representation learning. However, existing works focused on exacting temporal motif are not scalable to large-scale temporal graph data, due to their heavy computational costs or inherent inadequacy of parallelism. In this work, we propose a scalable parallel framework for exactly counting temporal motifs in large-scale temporal graphs. We first categorize the temporal motifs based on their distinct properties, and then design customized algorithms that offer efficient strategies to exactly count the motif instances of each category. Moreover, our compact data structures, namely triple and quadruple counters, enable our algorithms to directly identify the temporal motif instances of each category, according to edge information and relationship between edges, therefore significantly improving the counting efficiency. Based on the proposed counting algorithms, we design a hierarchical parallel framework that featuring both inter- and intra-node parallel strategies, and fully leverages the multi-threading capacity of modern CPU to concurrently count all temporal motifs. Extensive experiments on sixteen real-world temporal graph datasets demonstrate the superiority and capability of our proposed framework for temporal motif counting, achieving up to 538x speedup compared to the stateof-the-art methods. The source code of our method is available at: https://github.com/steven- ccq/FAST- temporal-motif.","Title: Green Synthesis of Phosphorescent Carbon Dots for Anticounterfeiting and Information Encryption\nYear: 2022\n\nAbstract: Room-temperature phosphorescent (RTP) carbon dots (CDs) have promising applications in bioimaging, anticounterfeiting, and information encryption owing to their long lifetimes and wide Stokes shifts. Numerous researchers are interested in developing highly bright RTP CDs using environmentally friendly and safe synthesis processes (e.g., natural raw materials and zero-pollution production pathways). In this study, we successfully synthesized RTP CDs using a hydrothermal process employing natural vitamins as a raw material, ethylenediamine as a passivator, and boric acid as a phosphorescent enhancer, which is referred to as phosphorescent CD (PCD). The PCDs exhibit both bright blue fluorescence emission and green RTP emission, with a phosphorescence lifetime as long as 293 ms and an excellent green afterglow visible to the naked eye for up to 7.0 s. The total quantum yield is 12.69%. The phosphorescence quantum yield (PQY) is up to 5.15%. Based on the RTP performance, PCDs have been successfully employed for anticounterfeiting and information protection applications. The results of this study provide a green strategy for the scalable synthesis of RTP materials, which is a practical method for the fabrication of RTP materials with high efficiency and long afterglow lifetimes.","Title: A Meta-learning based Stress Category Detection Framework on Social Media\nYear: 2022\n\nAbstract: ABSTRACT Psychological stress has become a wider-spread and serious health issue in modern society. Detecting stressors that cause the stress could enable people to take effective actions to manage the stress. Previous work relied on the stressor dictionary built upon words from the stressor-related categories in the LIWC (Linguistic Inquiry and Word Count), and focused on stress categories that appear frequently on social media. In this paper, we build a meta-learning based stress category detection framework, which can learn how to distinguish a new stress category with very little data through learning on frequently appeared categories without relying on any lexicon. It is comprised of three modules, i.e., encoder module, induction module, and relation module. The encoder module focuses on learning category-relevant representation of each tweet with Dependency Graph Convolutional Network and tweet attention. The induction module deploys Mixture of Experts mechanism to integrate and summarize a representation for each category. The relation module is adopted to measure the correlation between each pair of query tweets and categories. Through the three modules and the meta-training process, we can then obtain a model which learns to learn how to identify stress categories and can directly be employed to a new category with little labelled data. Our experimental results show that the proposed framework can achieve 75.3 accuracy with 3 labeled data for the rarely appeared stress categories. We also build a stress category dataset consisting of 12 stress categories with 1,553 manually labeled stressful microblogs which can help train AI models to assist psychological stress diagnosis.","Title: Fuzzy Grey Model for Forecasting Non-homogeneous Exponential Sequence\nYear: 2022\n\nAbstract: Getting accurate results when GM (1, 1) model is used for fitting and predicting approximate non-homogeneous exponential sequence, is a challenge. We sought to address this issue by combining Grey Theory and Credibility Theory, to develop a fuzzy GM (1, 1) model (FGM), which introduces the double exponential fuzzy numbers and its membership function. The expectation of fuzzy variables for replacing the non-homogeneous exponential sequence was calculated by Credibility Theory, i.e. the homogeneous process. The novel method yields unbiased results when used in fitting and predicting the tight non-homogeneous exponential sequence. Finally, we use an empirical case and a numerical sequence case to illustrate the effectiveness, feasibility, and optimization of the FGM (1, 1) model.","Title: A Friend-or-Foe framework for multi-agent reinforcement learning policy generation in mixing cooperative-competitive scenarios\nYear: 2022\n\nAbstract: Although multi-agent deep deterministic policy gradient is a classic deep reinforcement learning algorithm in multi-agent systems. It also has critical problems such as poor training stability and low policy robustness, which significantly limit the capability and application of the algorithm. So this article proposes an improved algorithm called friend-or-foe multi-agent deep deterministic policy gradient for solving the above problems. The main innovations are as follows: (1) inspired by the concept of friend-or-foe game theory, we modified the framework of the original multi-agent deep deterministic policy gradient by using two identical training networks with agents' optimal and worst actions input, which improves the robustness of training policies, and (2) we propose an action perturbation technique based on gradient-descent to expand the selection range of actions, thereby improving training stability of our proposing algorithm. Finally, we conducted multiple sets of comparative experiments between our friend-or-foe multi-agent deep deterministic policy gradient and original one in four authoritative mixed cooperative-competitive scenarios. The results show that our improving algorithm can simultaneously improve the training stability and the robustness of agents' generating policies in different complicated environments.","Title: A direct construction of continuous leakage-resilient (H)IBE scheme with CCA security from dual system encryption\nYear: 2023\n\nAbstract: Continuous leakage resilient semantically secure Identity-based Encryption (IBE) schemes created with dual system encryption technique were presented by Lewko et al. at TCC 2011 and Yuen et al. at Eurocrypt 2012, respectively. It has been a research challenge to achieve the security against chosen-ciphertext attacks (CCA). The previous attempts toward the CCA security rely on q-type assumptions, which are referred as non-static assumptions causing loose reduction in security proofs. In this paper, we provide a complete solution to the problem and show how to construct the continuous leakage-resilient IBE with weaker CCA security based on the dual system encryption technique, where the adversary is allowed to make continuous leakage queries. We are able to prove its security with static assumptions in the standard model. As a feature of our scheme, we allow leakage of multiple keys, i.e., leakage of the master secret key and the private key of user. Our scheme also enjoys better computational performance, since the round leakage parameter is independent of the plaintext space and has a constant size. Furthermore, our scheme can be easily extended to give the weaker CCA secure continuous leakage-resilient hierarchical identity-based encryption scheme with a short ciphertext length.","Title: Fine-Grained Question-Level Deception Detection via Graph-Based Learning and Cross-Modal Fusion\nYear: 2022\n\nAbstract: Automated deception detection has been found as a vital and concerned task, capable of assisting human users to assess truthfulness and detect deceptive behaviors in several situations (e.g., medical, legal, as well as occupational domains). As contact-free video cameras and data analysis techniques are leaping forward, leveraging one's visual, acoustic and textual information captured in a video can be cost-effective for deception detection. In this study, we aim at a fine-grained question-level deception detection task, focusing on detecting whether a subject lies or not in answering each question rather than providing an overall \"lie or not\" judgement. A Graph-based Cross-modal Fusion Model (GCFM) is presented to learn the inherent associations among the subject's reactions to different questions, plus a novel cross-modal attention mechanism to enhance the model's learning capability. As revealed by the experimental results on the two datasets, the proposed graph-based GCFM outperformed eight other methods, and its two alternatives (clustering K-means based and sequential learning LSTM based methods), achieving accuracy 88.14% and 86.91% on the two datasets, respectively. Besides, through association learning, GCFM could increase the accuracy by 1.87% and 4.33% on the two datasets, respectively. Furthermore, its cross-modal attention mechanism led to the improvement of accuracy by 2.44% and 2.95% on the two datasets, respectively.","Title: Coupling a Physical Replica with a Digital Twin: A Comparison of Participatory Decision-Making Methods in an Urban Park Environment\nYear: 2022\n\nAbstract: Public participation is crucial in promoting built environment quality. By using Nancuiping park in China as a case study, this research brings attention to the digital twin park compared to the physical replica in a participatory workshop. Using UAV oblique photography, we created a digital twin model of this park and divided it into six layers to better manage and analyze the environment. Bracing the 'bottom-up' design philosophy, in the workshop, we analyzed existing issues in the park and simulated built environment changes, taking suggestions and comments from participants into account to support the decision-making of the park's optimization. Our digital twin model and physical replica were assessed through a questionnaire in which 59 participants used 3 defined indicators: usability, interactivity, and scenario simulation and visualization quality. The results suggest that the physical replica is easier to use in the participatory design. However, the digital twin model can provide better interactivity and efficient scene simulation and visualization quality. The statistical analysis of the relationship between participants' feedback on the two models and their sociodemographics (age, gender, and education background) shows that age is a barrier to promoting digital twins for older participants. Meanwhile, the digital twin's highly interactive features and high-resolution visualization capability were attractive to the younger and well-educated participants. Our study indicates future directions to improve the urban digital twin by incorporating human feedback into the urban model, thus establishing a two-way interaction between the digital system, the physical environment, and human perceptions.","Title: Average Operation Time of Bundle Protocol in Delay/Disruption-Tolerant Networks\nYear: 2022\n\nAbstract: Performance analysis of the Bundle Protocol (BP) in Delay/ disruption-Tolerant Networks (DTN) has gained much interest. The analytic work of the average operation time (AOT) in BP, for different channel conditions and system parameters, though critical to understanding performance and designing system, is still incomplete. Existing results, such as the average file delivery time (AFDT), provide reasonably close estimates in some cases but exhibit large discrepancies in other cases. In this paper, we provide a holistic probabilistic analysis of the BP process, particularly in the number of error bundles and the position of the last error bundle in each and the last rounds of transmission. We provide, for the first time, an exact solution for the AOT of the BP process. The derivation works for both symmetric and asymmetric channels and is in general for any given maximum number of transmissions rounds. When the unlimited number of transmission rounds is considered, AOT becomes AFDT. The results are further utilized to select the optimal bundle size that gives the minimum file delivery time. Validation via simulations and comparison with existing work are also provided.","Title: Performance of XOR Rule for Decentralized Detection of Deterministic Signals in Bivariate Gaussian Noise\nYear: 2022\n\nAbstract: In this paper, we consider the performance of exclusive-OR (XOR) rule in detecting the presence or absence of a deterministic signal in bivariate Gaussian noise. Signals, when present at the two sensors, are assumed unequal, whereas the noise components have identical marginal distribution but are correlated. The sensors send their one-bit quantized data to a fusion center, which then employs the XOR rule to arrive at the final decision. Here we prove that, in the limit as the correlation coefficient r approaches 1, the optimum fusion rule for both parallel and tandem topologies is XOR with identical, alternating partitions (XORAP) of the observations at the sensors. We further quantify the asymptotic decrease of the Bayes error of XORAP towards zero as a constant multiplied by root 1- r, as r approaches 1. When compared to the asymptotic Bayes error of CLRT, which decreases to zero exponentially fast, as a function of 1/(1-r), the Bayes error of XORAP decreases to zero much slower.","Title: A Method of the Coverage Ratio of Street Trees Based on Deep Learning\nYear: 2022\n\nAbstract: The street trees coverage ratio provides reliable data support for urban ecological environment assessment, which plays an important part in the ecological environment index calculation. Aiming at the statistical estimation of urban street trees coverage ratio, an integrated model based on YOLOv4 and Unet network for detecting and extracting street trees from remote sensing images is proposed, and obtain the estimated street trees coverage ratio in images accurately. The experiments are carried out under self-made dataset, and the results show that the accuracy of street trees detection is 94.91%, and the street trees coverage ratio is 16.30% and 13.81% in the two experimental urban scenes. The MIoU of contour extraction is 98.25%, and the estimated coverage accuracy is improved by 6.89% and 5.79%, respectively. The result indicates that the proposed model achieves the automation of contour extraction of street trees and more accurate estimation of street trees coverage ratio."],"string":"[\n \"Title: Test-pattern-reduced decoding for turbo product codes with multi-error-correcting eBCH codes\\nYear: 2009\\n\\nAbstract: We present a method to reduce the number of test patterns (TPs) decoded in the Chase-II algorithm for turbo product codes (TPCs) constructed with multi-error-correcting extended Bose-Chaudhuri-Hocquengem (eBCH) codes. We classify TPs into different conditions based on the relationship between syndromes and the number of errors so that TPs with the same codeword are not decoded except the one with the least number of errors. For eBCH with code length of 64, simulation results show that over 50% of TPs need not to be decoded without any performance degradation.\",\n \"Title: Distributed Source Coding Under Noisy Transmission Environments\\nYear: 2007\\n\\nAbstract: Distributed source coding (DSC) has been attracting more and more research interests recently, particularly for mobile wireless applications. However, most existing DSC schemes assume that the coded information is transmitted error free to the decoder end. In this paper, we report our latest investigations on distributed source coding under noisy transmission environments. It is expected that these investigations provide useful guidelines for practical DSC system design when the transmission is actually not error free. Especially, many current schemes in DSC adopted the channel coding principles to accomplish the source coding tasks. We shall illustrate that the channel coding-based DSC schemes possess some inherent noise combating capability to recover possible channel errors under noisy transmission environments. Specifically, we shall report the investigations of Turbo DSC under various environments: error free, noisy transmission with additional forward error correction (FEC) and noisy transmission without FEC. Our experimental results show that with the same number of bits transmitted through noise channel, the unprotected Turbo DSC outperforms the FEC protected Turbo DSC.\",\n \"Title: A categorized-registry model for grid resource publication and discovery using software agents\\nYear: 2004\\n\\nAbstract: This paper presents a categorized-registry model for Grid Resource Publication and Discovery(GRPD) using software agents. We use Common Resource Model(CRM) specification to describe manageable resources as Open Grid Services Architecture(OGSA) services. We also adopt two-level registry mechanism to register corresponding resources of a Virtual Organization(VO) in order to obtain high GRPD efficiency. The “Index” node of a VO hosts the general registry. Other specific categorized registries are distributed in the VO. A large-scale Grid system may contain many VOs. “Index” nodes from various VOs connect to each other in Peer-to-Peer(P2P) mode instead of hierarchical mode. Software agent is a powerful high-level tool for modeling a complex software system. It is adopted to implement GRPD efficiently.\",\n \"Title: A lower bound on greedy embedding in euclidean plane\\nYear: 2010\\n\\nAbstract: Greedy embedding is the key of geometric greedy routing in p2p networks It embeds a graph (the topological structure of the p2p network) in a metric space such that between any source-destination pair, there is a distance decreasing path for message delivery It is known that any graph can be greedily embedded in the hyperbolic plane with using O(logn) bits for each node's coordinates [7] Interestingly, on greedy embedding in the Euclidean plane, existing embedding algorithms result in coordinates with ${\\\\it \\\\Omega}(n)$ bits It was recently proved that ${\\\\it \\\\Omega}(n)$ is a lower bound of the coordinates' bit length if one uses Cartesian or polar coordinate system and preserves the planar embedding of a planar graph when greedily embedding it in the Euclidean plan [2] In this paper we strengthen this result by further proving that ${\\\\it \\\\Omega}(n)$ is still a lower bound even if the graph is allowed to take free embedding in the plane.\",\n \"Title: Soft Information Relaying for Distributed Turbo Product Codes (SIR-DTPC)\\nYear: 2010\\n\\nAbstract: In this letter, we propose a Distributed Turbo Product Code (DTPC) with soft information relaying over cooperative network using block Extended Bose Chaudhuri Hochquenghem (EBCH) codes as component codes. The source broadcasts extended EBCH coded frames to the destination and to a preassigned relay. After soft-decoding, the received sequences and obtaining the Log-Likelihood Ratio (LLR) values, the relay constructs a product code by arranging the decoded bit sequences in rows and re-encoding them along the columns using a novel soft block encoding technique to obtain soft parity bits with different reliabilities that can be used as soft Incremental Redundancy (IR) that is forwarded to the destination. We compared the simulation results in Additive White Gaussian Noise (AWGN) channel with our previous work for Decode and Forward (DF) DTPC and with noncooperative case. The proposed system shows better Bit Error Rate (BER) performance and less sensitivity to the relay's position.\",\n \"Title: Defence against Botnets: A Formal Definition and a General Framework\\nYear: 2013\\n\\nAbstract: Botnets have contributed to the significant part of the increasing malicious activities such as Distributed Denial of Service (DDoS), spam, and click fraud. Based on the analysis on the basic and essential characters of botnet, this paper deals with the botnet in two aspects: formal definition and general framework, covering various types of botnets overall. Through the formal definition and the general framework, the essential components of the botnet (i.e. botmaster, Command and Control mechanism, and bots) are described in detail and the features of the vital Command and Control (C&C) mechanism are augmented. The formal definition for botnet, to the best of our knowledge, is first proposed and the general framework, analyzed in some case studies, is not only helpful to interpret the existing botnets in the real world, but also beneficial to the implement of the potential botnets in the future.\",\n \"Title: A trellis-based technique for blind channel estimation and equalization.\\nYear: 2004\\n\\nAbstract: In this paper, we present a trellis-based blind channel estimation and equalization technique coupling two kinds of adaptive Viterbi algorithms. First, the initial blind channel estimation is accomplished by incorporating the list parallel Viterbi algorithm with the least mean square (LMS) updating approach. In this operation, multiple trellis mappings are preserved simultaneously and ranked in terms of path metrics. Equivalently, multiple channel estimates are maintained and updated once a single symbol is received. Second, the best channel estimate from the above operation will be adopted to set up the whole trellis. The conventional adaptive Viterbi algorithm is then applied to detect the signal and further update the channel estimate alternately. A small delay is introduced for the symbol detection and the decision feedback to smooth the noise impact. An automatic switch between the above two operations is also proposed by exploiting the evolution of path metrics and the linear constraint inherent in the trellis mapping. Simulation has shown an overall excellent performance of the proposed scheme in terms of mean square error (MSE) for channel estimation, robustness to the initial channel guess, computational complexity, and channel equalization.\",\n \"Title: Scalable distance-based outlier detection over high-volume data streams\\nYear: 2014\\n\\nAbstract: The discovery of distance-based outliers from huge volumes of streaming data is critical for modern applications ranging from credit card fraud detection to moving object monitoring. In this work, we propose the first general framework to handle the three major classes of distance-based outliers in streaming environments, including the traditional distance-threshold based and the nearest-neighbor-based definitions. Our LEAP framework encompasses two general optimization principles applicable across all three outlier types. First, our “minimal probing” principle uses a lightweight probing operation to gather minimal yet sufficient evidence for outlier detection. This principle overturns the state-of-the-art methodology that requires routinely conducting expensive complete neighborhood searches to identify outliers. Second, our “lifespan-aware prioritization” principle leverages the temporal relationships among stream data points to prioritize the processing order among them during the probing process. Guided by these two principles, we design an outlier detection strategy which is proven to be optimal in CPU costs needed to determine the outlier status of any data point during its entire life. Our comprehensive experimental studies, using both synthetic as well as real streaming data, demonstrate that our methods are 3 orders of magnitude faster than state-of-the-art methods for a rich diversity of scenarios tested yet scale to high dimensional streaming data.\",\n \"Title: Up-Down Links Dualpath Greedy Routing Protocol for Wireless Sensor Networks\\nYear: 2012\\n\\nAbstract: Greedy geographic routing is attractive in wireless sensor networks because of its efficiency and scalability. This paper presents an up-down links dualpath greedy routing (UDLDGR) protocol for wireless sensor networks. The routing protocol not only reserves the features of greedy forwarding algorithm, which is simple, efficient, but also uses different relay nodes to serve as routing nodes for up and down routing paths, makes the energy consumption more balanced. The greatest advantage of UDLDGR is it trades off only small cost for the source node to obtain two different transmission paths information. The multipath strengthens the network reliability, such as load balancing and robustness to failures. Our simulation results show that UDLDGR can improve system lifetime by 20---100% compared to single path approaches.\",\n \"Title: On the unequal error protection for progressive image transmission.\\nYear: 2007\\n\\nAbstract: In this paper, we consider the unequal error protection (UEP) for progressive image transmission when the coded packet size is fixed. First, we prove that, for the source code with convex rate-distortion (R-D) function and practically used channel codes, the channel code rate for each packet in the optimal rate allocation is nondecreasing indeed. Then, we give an upper bound for the channel code rate of the last packet so that the number of rate allocations in the exhaustive search can be predicted. Further, we propose a heuristic optimization method which has low complexity and obtains performance approaching to the optimal solutions for various channel conditions and transmission rates.\",\n \"Title: CNP-based Implementation of Service-oriented Workflow Mapping in SHGWMS\\nYear: 2008\\n\\nAbstract: ShanghaiGrid has a complex service-oriented infrastructure. Workflow management is emerging as one of the most important part of it. Because the grid environment is very dynamic and the services are shared among many users, it is impossible to optimize the workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible. In this paper, we propose a method of using Contract Net Protocol(CNP) to implement service-oriented workflow mapping in ShanghaiGrid workflow management system(SHGWMS). Three types of workflow in SHGWMS are denoted as Abstract workflow(AW), Concrete workflow(CW) and Executable workflow(EW). Belief-Desire-Intention(BDI) agent technology in SHGWMS helps the system meet challenges from the grid context. CNP provides a very proper negotiation model for agents. The problem of workflow mapping has been transferred to the problem of multi-agent negotiation with the help of CNP model in SHGWMS. We also propose AW2CW mapping algorithm and CW2EW mapping algorithm to accomplish service-oriented workflow mapping.\",\n \"Title: Progressive image transmission with genetic algorithm-based optimization and multiple cyclic redundancy check structure\\nYear: 2008\\n\\nAbstract: We consider the transmission of progressive image data over noisy channels when the coded packet size is fixed. The concatenated cyclic redundancy check (CRC) codes and rate-compatible punctured turbo codes are used for error control and detection. In such an application, the distortion-based optimal channel rate allocation for unequal error protection is complex. We first propose a suboptimal genetic algorithm-based method that not only largely reduces the optimization complexity but also obtains performance approaching to the results of a brute force search. In addition, because a large packet size is usually applied when turbo codes are used due to the fact that the coding gain is proportional to the packet size for a given code rate, a single remaining bit error after channel decoding may result in CRC failure and hence the discard of the entire packet Therefore, we further propose a multiple-CRC structure for certain data packets so that more correctly decoded data could be used in source decoding. The promising performance of the proposed scheme has been demonstrated through simulation. (C) 2008 SPIE and IS&T.\",\n \"Title: Study of objective management appraisal system for the university archives-based on the Grey Clustering Algorithm and association rule\\nYear: 2012\\n\\nAbstract: This paper applies the Grey Clustering Algorithm to the objective management appraisal for university archives, presents the appraisal classification, establishes an evaluation model and gives an example using the Grey Clustering for clear and reliable evaluation. This paper further utilizes the Association Rule and obtains related data from a university's database to find the internal relations between the university and the appraisal result, based on the improved Apriori Algorithm.\",\n \"Title: Cost-Driven web service selection using genetic algorithm\\nYear: 2005\\n\\nAbstract: Web services composition has been one of the hottest research topics. But with the ever increasing number of functional similar web services being made available on the Internet, there is a need to be able to distinguish them using a set of well-defined Quality of Service (QoS) criteria. The cost is the primary concern of many business processes. In this paper, we propose a new solution using Genetic Algorithm (GA) in cost-driven web service selection. GA is utilized to optimize business process composed of many service agents (SAg). Each SAg corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process with taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using local service selection strategy. The global optimal solution might also be achieved with proper GA parameters.\",\n \"Title: A workflow services middleware model on ShanghaiGrid\\nYear: 2004\\n\\nAbstract: The ShanghaiGrid is an ongoing grid computing environment (GCE) based on grid service standards and the open grid services architecture. The ShanghaiGrid is a City Grid, which is to provide a general shared information grid platform. Based on this point, a workflow management system is very import especially for user-defined workflow. By using the workflow, users in GCE would compose several grid services as a new service and provide it to others. This enlarges the extensibility and business-originated usage in the GCE. This paper discusses the type of workflow, proposes a model of client-side workflow management system, and the design of several important workflow services. A service discovery process based on workflow is also given.\",\n \"Title: Robust image transmission based on wavelet tree coding and EREC\\nYear: 2001\\n\\nAbstract: We propose a robust image transmission scheme based on wavelet tree coding and error resilient entropy coding (EREC). After the wavelet decomposition, the coefficients are re-arranged into wavelet trees according to their spatial representation. Each wavelet tree is coded independently so that the scheme is essentially a block-based coding in the spatial domain. Since the self-similarity across subbands is preserved, a high source coding efficiency can be achieved. EREC is then adopted to enhance the error resilience capability of the compressed bitstream. At the receiving end, the automatic re-synchronization of each block is obtained. Furthermore, the bits impacted by the error propagation are more likely located in the low bit-layers so that the resultant degradation is less severe in terms of PSNR. Experimental results show that this proposed scheme can achieve a good error resilient performance\",\n \"Title: Evaluation of a Novel Load-Balancing Algorithm with Variable Granularity\\nYear: 2008\\n\\nAbstract: In this paper, we propose a Uniform Fine-grain Frame Spreading (UFFS-k, where k is the aggregate factor) algorithm to guarantee packet ordering in load-balanced switches by assigning k cells of the same flow to the fixed k successive intermediate inputs. The UFFS-k algorithm first guarantees packet ordering at input linecards without any computation and communication overhead. As the simulation results demonstrate, UFFS-k offers improved delay performance among existing scheduling algorithms that guarantee packet ordering.\",\n \"Title: Introduction to an agent-based grid workflow management system\\nYear: 2005\\n\\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. One of the most important grid services is workflow management. Grid workflow applications are also emerging as one of the most interesting application classes for the grid. In this paper, we give an introduction to our agent-based grid workflow management system (AGWMS). AGWMS has a four-layer framework. It bases on the adapter middleware and uses a multi-agent platform to make the system more robust, flexible and intelligent. Artificial Intelligence (AI) planning technology is also utilized to generate the agent plan automatically. Our AGWMS is a novel one.\",\n \"Title: Joint Source and Channel Coding for Image Transmission over Time Varying Channels\\nYear: 2007\\n\\nAbstract: In this paper, the joint source and channel coding for progressive image transmission over channels with varying SNR is considered. Since the feedback of channel status information generally lags behind the channel variation and the optimization process often causes high computational complexity, it is appropriate to optimally allocate the given bandwidth between the source and channel codes based on the statistics of the channel rather than a specific SNR. In such case, the optimization objective function is no longer in a recursive format and the computational complexity with exhaustive search for the optimal allocation is prohibitive. In this paper, we present a simple yet very effective genetic algorithm (GA) based optimization method so that the near-optimal channel rate allocation can be obtained through crossover and mutation operations over a candidate pool. Simulation shows that this GA-based method always approaches to the optimal results of the brute force search for the considered scenario, but with much lower complexity.\",\n \"Title: An Adaptive Spatio-Temporal Error Concealment Scheme Based on H.264/AVC.\\nYear: 2011\\n\\nAbstract: An Adaptive Spatio-Temporal Error Concealment (ASTEC) scheme based on H.264/AVC is proposed in the paper to improve the quality of the rebuilt frame in H.264/AVC decoder side. Combining the spatial error concealment method with the temporal one, a new scheme is proposed to conceal an erroneous macro block according to its encoded mode. The temporal error concealment scheme adopts the weighted Boundary Matching Algorithm to recover the erroneous macro block. The spatial error concealment scheme recovers the erroneous macro block by exploiting the directional interpolation which subdivides the macro block according to the number and the direction of edges going through it. Experiments show that the proposed concealment scheme can restrain the diffusion of erroneous macro block and improve the quality of the rebuilt frame subjectively as well as objectively. © 2011 ACADEMY PUBLISHER.\",\n \"Title: Predicting Content Virality in Social Cascade\\nYear: 2013\\n\\nAbstract: Predicting why and how certain content goes viral is attractive for many applications, such as viral marketing and social network applications, but is still a challenging task today. Existing prediction algorithms focus on predicting the content popularity without considering the timing. Those algorithms are based on information that may be uncommon or computationally expensive. This paper proposes a novel and practical algorithm to predict the virality of content. Instead of predicting the popularity, the algorithm predicts the time for the social cascade size to reach a given viral target. The algorithm is verified by the data from a popular social network - Digg.com and 2 synthesize datasets under different conditions. The results prove that the algorithm can achieve the lower bound with a practical significance for the time to reach the viral target.\",\n \"Title: A novel product coding and recurrent alternate decoding scheme for image transmission over noisy channels\\nYear: 2003\\n\\nAbstract: In this letter, we present a novel product channel coding and decoding scheme for image transmission over noisy channels. Two convolutional codes with at least one recursive systematic convolutional code are employed to construct the product code. Received data are decoded alternately in two directions. A constrained Viterbi algorithm is proposed to exploit the detection results of cyclic redundancy check codes so that both reduction in error patterns and fast decoding speed are achieved. Experiments with image data coded by the algorithm of set partitioning in hierarchical trees exhibit results better than those currently reported in the literature.\",\n \"Title: MAP Decoding of Variable Length Codes With Self-Synchronization Strings\\nYear: 2007\\n\\nAbstract: Maximum a posteriori probability (MAP) decoding of Huffman-equivalent variable-length codes (VLCs) has two undesired features. One is the high decoding complexity, and the other is the discrepancy between the objective of MAP decoding and the Levenshtein distance which is commonly used as the performance metric. In this correspondence, improvement over these two issues is targeted through extracting self-synchronization information in VLC coded sequence and incorporating it into MAP decoding. It shown that self-synchronization strings (SSSs) are concatenation of Huffman codewords and can be readily found. Occurrence probabilities of SSSs are then analyzed. By using this self-synchronization information, MAP decoding is split into multiple decoding of short data segments so that both decoding performance improvement and complexity reduction are obtained. Simulation results demonstrate the effectiveness of the proposed method.\",\n \"Title: On the performance of turbo codes-based hybrid ARQ with segment selective repeat in WCDMA.\\nYear: 2006\\n\\nAbstract: In this paper, a new turbo codes-based hybrid automatic repeat request (TC-HARQ) scheme with segment selective repeat (SSR) is proposed. The main strategy is, upon retransmission, to repeat the data that are most important for the next round of decoding based on the distribution of residual errors after current decoding. The performance in terms of reliability and throughput is analyzed. To adapt to correlated fading channels where an interleaver is always employed before transmission, we further modify the SSR strategy so that data having experienced correlated deep fading are selected for retransmission. Finally, this proposed scheme is applied to the wideband code division multiple access (WCDMA) system under frequency selective fading channels. Simulation results demonstrate that in all single and multiple user cases, SSR-based TC-HARQ leads to significant throughput improvement with similar bit error rate (BER) performance as compared to type-I TC-HARQ.\",\n \"Title: Peking University at TRECVID 2008: High Level Feature Extraction\\nYear: 2008\\n\\nAbstract: We participated in one task of TRECVID 2008, that is, the high-level feature extraction (HLFE). This paper presents our approaches and results on the HLFE task. We mainly focus on exploring the data imbalance learning in this year, and propose two methods for this problem: (1) adaptive borderline-SMOTE and under-sampling SVM (ABUSVM), and (2) concept category. Our approach can be divided into two phases: feature representation and data imbalance learning. In feature representation phase, four low-level visual features namely color moment grid (CMG), local binary pattern (LBP), Gabor wavelet texture (Gabor), and edge histogram layout (EHL) are combined together in an \\\"early fusion\\\" manner. In data imbalance learning phase, ABUSVM and concept category are employed jointly to handle the data imbalance problem. In addition, we also investigate the fusion of 2005 and 2008 training data to improve the performance. The experimental results show our four visual features, ABUSVM, and concept category are effective to improve the performance, while the fusion of 2005 training data decreases the result.\",\n \"Title: Understanding the pathogenesis of Kawasaki disease by network and pathway analysis.\\nYear: 2013\\n\\nAbstract: Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF-kappa B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.\",\n \"Title: Multi-User Cooperative Communications with Relay-Coding for Uplink IMT-Advanced 4G Systems\\nYear: 2009\\n\\nAbstract: Adoption of relay stations has been commonly accepted as a key technique for future IMT-advanced 4G systems to improve the link performance. While study in relay systems is often carried out for individual users independently, in this paper, we present a design termed as relay-based multi-user cooperative communication specifically for the uplink of 4G systems. In this system, data streams from multiple users are coded at the relay with an invertible matrix in finite field. These coded data, with information of one user being spread into other data streams, are forwarded by the RS to the base station (BS). The relayed data received at the BS will work together with those received through the direct links between mobile stations (MS) and BS to implement a cooperative process. This is carried out using a turbo decoding process that alternates the decoding between a multi-user decoder and a number of single-user decoders. It is shown through the simulations that the decoding converges within two or three iterations, yet indeed provides significant gains compared with a reference relay system where each user is processed individually.\",\n \"Title: Uep For Progressive Image Transmission With Ga-Based Optimization\\nYear: 2007\\n\\nAbstract: In this paper, we consider the transmission of progressive image data over noisy channels with the protection of rate-compatible punctured Turbo codes (RCPT) concatenated with multiple cyclic redundancy check (CRC) codes. To optimally allocate the given bandwidth resource for unequal error protection (UEP), a genetic algorithm (GA) based method is proposed to reduce the optimization complexity. In addition, a structure of multiple CRC blocks is employed in some data packets so that more correctly decoded data could be used in decoding. Simulation has demonstrated promising results of the proposed scheme.\",\n \"Title: Transmit Antenna Selection Strategy in Amplify-and-Forward MIMO Relaying\\nYear: 2009\\n\\nAbstract: We compare the outage performance by applying transmit antenna selection strategies to amplify-and-forward protocol in the MIMO relaying scenario. Although antenna selection is a suboptimal form of beamforming, it enjoys the advantages of tractable optimization and low feedback overhead. Specifically, by combining transmit antenna selection strategies with amplify-and-forward protocol, we propose two suboptimal strategies, TAS-SD&RD and TAS-SR&RD, and compare their performance with the optimal strategy, TAS-Optimal. By observation of simulation, the suboptimal strategy TAS-SD&RD can achieve the full diversity order with only a small performance loss compared with the optimal strategy TAS-Optimal in some antenna configuration scenarios.\",\n \"Title: Vegetation Coverage Change Trend in Inner Mongolia of China during 1998-2008.\\nYear: 2011\\n\\nAbstract: Vegetation is sensitive to reflect the change of ecological environment, so it is significant to study the vegetation dynamics for ecological environment protection and ecological early warning. Based on the time series of the SPOT/VEGETATION NDVI dataset, this paper has obtained the spatial distribution of NDVI in Inner Mongolia (IM), analyzed the characteristics of NDVI change trend in the period of 1998-2008 by Maximum Value Composites (MVC) and Mann-Kendall test. The main findings are as follows: (1) NDVI time series in most regions of IM has tendency in the recent 10 years. (2) The significant increased areas of vegetation cover are mostly distributed in the area of severe desertification, and the significant decreased areas of vegetation cover are mainly located in the typical steppes.\",\n \"Title: Defect detection of IC wafer based on two-dimension wavelet transform\\nYear: 2010\\n\\nAbstract: Defect detection of integrated circuit (IC) wafer based on two-dimension wavelet transform (2-D DWT) is presented in this paper. By utilizing the characteristics many of the same chips in a wafer, three images with defects located in the same position and different chips are obtained. The defect images contain the standard image without any defects. 2-D DWT presented in the paper can extract the standard image from the three defect images. The algorithm complexity of the method is close to that of 2-D DWT. After obtaining the standard image, the speed and accuracy of defects detection can be greatly enhanced using the detection method presented in the paper. Using the image gray-scale matching technology, impact of illumination on IC defect detection is solved. Experiments demonstrate that 2-D DWT is fast and accurate to defects detection in an IC image, and the method has high robustness for illumination.\",\n \"Title: Error Resilient Multiple Description Coding Based On Wavelet Tree Coding And Erec For Wireless Networks\\nYear: 2005\\n\\nAbstract: In this paper, we propose an integrated error resilient MDC scheme for wireless networks with both packet loss and random bit errors. Two descriptions are first generated independently by using index assignment MDSQ. For each description, multiple bit streams are then generated based on wavelet trees along the spatial orientations. The spatial-orientation trees in the wavelet domain are individually encoded using SPIHT Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt EREC to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bilstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients.\",\n \"Title: Turbo codes-based image transmission for channels with multiple types of distortion.\\nYear: 2008\\n\\nAbstract: Product codes are generally used for progressive image transmission when random errors and packet loss (or burst errors) co-exist. However, the optimal rate allocation considering both component codes gives rise to high-optimization complexity. In addition, the decoding performance may be degraded quickly when the channel varies beyond the design point. In this paper, we propose a new unequal error protection (UEP) scheme for progressive image transmission by using rate-compatible punctured Turbo codes (RCPT) and cyclic redundancy check (CRC) codes only. By sophisticatedly interleaving each coded frame, the packet loss can be converted into randomly punctured bits in a Turbo code. Therefore, error control in noisy channels with different types of errors is equivalent to dealing with random bit errors only, with reduced turbo code rates. A genetic algorithm-based method is presented to further reduce the optimization complexity. This proposed method not only gives a better performance than product codes in given channel conditions but is also more robust to the channel variation. Finally, to break down the error floor of turbo decoding, we further extend the above RCPT/CRC protection to a product code scheme by adding a Reed-Solomon (RS) code across the frames. The associated rate allocation is discussed and further improvement is demonstrated.\",\n \"Title: A Real-Time Transaction Approach for Grid Services: A Model and Algorithms\\nYear: 2004\\n\\nAbstract: Because transactions in Grid applications often have deadlines, effectively processing real-time transactions in Grid services presents a challenging task. Although real-time transaction techniques have been well studied in databases, they can not be directly applied to the Grid applications due to the characteristics of Grid services. In this paper 3, we propose an effective model and corresponding coordination algorithms to handle real-time transactions for Grid services. The model can intelligently discover required Grid services to process specified subtransactions at runtime, and invoke the algorithms to coordinate these services to satisfy the transactional and real-time requirements, without users involvement in the complex process. We use a Petri net to validate the model and algorithms.\",\n \"Title: A mobile robot prototype for inspection of overhead bundled conductors\\nYear: 2013\\n\\nAbstract: A new mobile robot prototype for inspection of overhead bundled conductors is proposed. The mobile platform is composed of 4 arms. And there is a motorized rubber wheel on the end of each arm. When the robot runs on a transmission line (eg. 500kv, 4-bundle conductors), its wheels use the lower 2 conductors as a support. Two wheels ride on the left lower line, and the others ride on the right one. Along the direction of the lines, the 4 wheels are arranged by a sequence of 1 front wheel, 2 middle wheels and 1 rear wheel. It could roll over some obstacles (compression splices, vibration dampers, etc). Each arm has 2 degrees of freedom, therefore it could clear other types of obstacles (spacers, suspension clamps, etc).\",\n \"Title: An Efficient Stopping Criterion for Turbo Product Codes\\nYear: 2007\\n\\nAbstract: In this letter, a stopping criterion using the error- detecting capability of linear block codes is proposed for the decoding of turbo product codes. The iterative decoding is stopped when the outputs from the Chase decoder are valid codewords for all rows and columns simultaneously. Simulation shows that the proposed method can reduce about one and half iterations compared with an existing stoppi...\",\n \"Title: Asymptotic Performance of Two-Hop Amplify-and-Forward MIMO Relaying with Transmit Antenna Selection\\nYear: 2010\\n\\nAbstract: The asymptotic performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relay network over Rayleigh-fading channels is analyzed. Assuming that the source and destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form statistics of received signal-to-noise ratio (SNR) around original, and present the asymptotic average symbol error rate (SER). By analyzing the high SNR performance, we show that the diversity order, min {NS NR, NR ND} can be achieved for the transmission. The optimal relay selection problem, selecting the relay that minimizes the average SER, is also analyzed which shows that the position of the selected optimal relay depends on the number of antenna of source, relay, and destination. Numerical results that confirm our analysis are also presented in the paper.\",\n \"Title: ECBRP: An Efficient Cluster-Based Routing Protocol for Real-Time Multimedia Streaming in MANETs\\nYear: 2011\\n\\nAbstract: The dynamic characteristics of wireless networks and stringent QoS requirements of multimedia applications identify significant challenges for providing QoS guarantees for real-time multimedia streaming in such wireless environment. QoS routing protocols can decisively contribute to the QoS provision of network systems. This paper proposes an efficient cluster-based routing protocol (ECBRP) for real-time multimedia streaming in mobile ad hoc networks. First, to improve the stability of clusterheads, we introduce a new algorithm of cluster formation, in consideration of the node mobility and connectivity. Second, a link-broken detection mechanism is designed, which is able to distinguish whether packet loss is due to mobility or congestion, and to make proper reaction. This mechanism contributes to reduce route overhead, and to increase the decodable ratio of video frame at the application layer as well. Third, the routing protocol is enhanced via an adaptive packet salvage strategy, in order to alleviate the congestion in consideration of the characteristics of multimedia traffic. Our simulation experiment results demonstrate that the ECBRP leads to more stable cluster formation than the CBRP, and 80% decreases in the frequency of clusterhead changes against CBRP. As a result, the quality of real-time multimedia streaming is improved significantly, in terms of decodable frame ratio, delay and delay jitter, etc.\",\n \"Title: Uplink Power Control For An Sc-Fdma Mobile Cellular System\\nYear: 2008\\n\\nAbstract: The uplink power control is essentially important to the link performance and the system stability. By analyzing the SC-FDMA system's interference character, we view the SC-FDMA system as a modified OFDMA system with multi-channel model, and accordingly propose a power control scheme composed of intra-cell and inter-cell power control based on the multi-channel model. Especially the Inter-cell power control based on the interference overload with the form of frequency dependent and event triggered, along with the intra-cell power control, can achieve the target IoT in NodeBs and ensure its stability. This conclusion is achieved by our multi-cell simulation implemented with this power control scheme.\",\n \"Title: Joint source and channel decoding with symbol re-alignment\\nYear: 2006\\n\\nAbstract: The maximum a-posteriori probability (MAP) decoding of Huffman variable-length codes (VLCs) has been widely used in the joint source and channel decoding. This method exploits both source memory information and channel status information, but does not consider the symbol re-alignment as the conventional Huffman decoding does. In this letter, we show that self-synchronization strings (SSSs) of VLCs can be readily found and used with the MAP decoding. As a result, the performance of symbol error rate based on Levenshtein distance can be improved, with reduced decoding complexity.\",\n \"Title: Asymptotic performance of amplify-and-forward MIMO relaying with transmit antenna selection.\\nYear: 2010\\n\\nAbstract: This paper proposes two schemes, TAS-SD&RD and TAS-SR&RD, in which transmit antenna selection (TAS) strategies are combined\\n with amplify-and-forward (AF) protocol in MIMO relaying scenario considering the destination has only limited channel state\\n information (CSI) of the source-to-relay channel, and analyzes asymptotic performance of the two schemes. The source, destination,\\n and relay are equipped with multiple antennas, denoted by N\\n S, N\\n D, and N\\n R, respectively. Specifically, the paper derives the asymptotic outage probability and symbol error rate (SER) of the proposed\\n schemes in the cooperative AF MIMO relaying scenario. These analyses in high SNR regime lead to the conclusion that TAS-SD&RD\\n and TAS-SR&RD can achieve full diversity order, N\\n S\\n N\\n D + NR min {N\\n S,N\\n D}, in some antenna configurations of the cooperative scenario. Numerical results that confirm our analyses are also presented\\n in the paper.\",\n \"Title: Distributed power allocation for sink-centric clusters in multiple sink wireless sensor networks.\\nYear: 2010\\n\\nAbstract: Due to the battery resource constraints, saving energy is a critical issue in wireless sensor networks, particularly in large sensor networks. One possible solution is to deploy multiple sink nodes simultaneously. Another possible solution is to employ an adaptive clustering hierarchy routing scheme. In this paper, we propose a multiple sink cluster wireless sensor networks scheme which combines the two solutions, and propose an efficient transmission power control scheme for a sink-centric cluster routing protocol in multiple sink wireless sensor networks, denoted as MSCWSNs-PC. It is a distributed, scalable, self-organizing, adaptive system, and the sensor nodes do not require knowledge of the global network and their location. All sinks effectively work out a representative view of a monitored region, after which power control is employed to optimize network topology. The simulations demonstrate the advantages of our new protocol.\",\n \"Title: Content-based multiple bitstream image transmission over noisy channels.\\nYear: 2002\\n\\nAbstract: In this paper, we propose a novel combined source and channel coding scheme for image transmission over noisy channels. The main feature of the proposed scheme is a systematic decomposition of image sources so that unequal error protection can be applied according to not only bit error sensitivity but also visual content importance. The wavelet transform is adopted to hierarchically decompose the image. The association between the wavelet coefficients and what they represent spatially in the original image is fully exploited so that wavelet blocks are classified based on their corresponding image content. The classification produces wavelet blocks in each class with similar content and statistics, therefore enables high performance source compression using the set partitioning in hierarchical trees (SPIHT) algorithm. To combat the channel noise, an unequal error protection strategy with rate-compatible punctured convolutional/cyclic redundancy check (RCPC/CRC) codes is implemented based on the bit contribution to both peak signal-to-noise ratio (PSNR) and visual quality. At the receiving end, a postprocessing method making use of the SPIHT decoding structure and the classification map is developed to restore the degradation due to the residual error after channel decoding. Experimental results show that the proposed scheme is indeed able to provide protection both for the bits that are more sensitive to errors and for the more important visual content under a noisy transmission environment. In particular, the reconstructed images illustrate consistently better visual quality than using the single-bitstream-based schemes.\",\n \"Title: Tightened upper bounds for distributed Alamouti's code with a non-regenerative relay\\nYear: 2012\\n\\nAbstract: In this paper, we consider a cooperative system with distributed Alamouti's code that includes a source, a non-regenerative relay and a destination. The relay uses the amplify-and-forward protocol and all links experience independent Rayleigh fading. First, we present a novel approximation method in the series expansion for the error function. Then, we derive, based on the conditional expectation method, an upper bound of the BER performance in a summation of number of easily calculated components. This bound exhibits the even approximation errors for all SNR range and approaches to the exact system performance when the number of components increases. The upper bound is validated with simulation results and it is more accurate and flexible compared with other approximation methods.\",\n \"Title: Bipartite Graph Based Entity Ranking for Related Entity Finding\\nYear: 2011\\n\\nAbstract: Related entity finding (REF) is a promising application, which aims to return a list of related entities given a query that describes the source entity, the specific type of target entities, and the relation between the source entity and target entities. One typical entity ranking strategy is to rank the candidate entities based on the co-occurrence between the candidate entities and the given query. However, such a strategy is inadequate to rank entities properly especially for those related but unpopular entities. In this paper, we propose a bipartite graph based entity ranking method, which leverage the Co-List relationship between candidate entities (i.e., entities co-occurring in the same structured/unstructured lists) to help improve the entity ranking. Specifically, we first estimate the initial relevance scores for the candidate entities based on a generative probabilistic model. We then construct a bipartite graph based on Co-List relation between candidate entities, and apply an iterative refinement process analogous to heat diffusion on the graph to propagate the relevance scores over entities. Finally the candidate entities are ranked according to their refined scores. We further develop an optimization framework for the iterative refinement process in our ranking method. Experimental results on the data collection from the TREC 2010 Entity Track show the effectiveness of our proposed method.\",\n \"Title: Robust image transmission based on wavelet tree coding, error resilient entropy coding, and error concealment\\nYear: 2004\\n\\nAbstract: A scheme with three key components including wavelet tree coding, error resilient entropy coding (EREC), and error concealment is proposed for robust image coding and transmission over noisy channels. First, we individually encode the spatial-orientation trees in the wavelet domain using the algorithm of set partitioning in hierarchical trees (SPIHT). Error propagation is thus limited because multiple independent bit streams are generated. Meanwhile, a high source coding efficiency is also preserved because the self-similarity property in each wavelet tree remains intact. Next, we use EREC to reorganize these variable-length bit streams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bit stream can be automatically obtained at the receiver Finally, to alleviate the possible catastrophic image degradation that may result from errors in the beginning of the bit streams, we propose an error concealment technique to constrain the EREC decoding as well as to postprocess the decoded wavelet coefficients. As a result of the error concealment, the EREC decoding complexity is reduced and the reconstructed image quality is significantly improved. Experimental results demonstrate an excellent error resilient performance of the proposed scheme. (C) 2004 SPIE and IST.\",\n \"Title: On Succinctness of Geometric Greedy Routing in Euclidean Plane\\nYear: 2009\\n\\nAbstract: Geometric greedy routing uses (virtual) geographic point locations as addresses for the purposes of routing, while routing decisions are made by each node individually based only on local information. It requires that the network topology is greedily embedded in a metric space through assigning virtual coordinates to the nodes in the network. Recent research pointed out that such scheme is significantly more efficient than other traditional routing schemes only if the virtual coordinates are succinctly represented (i.e., using O(poly(log n)) bits per coordinate) in the greedy embedding, an issue that has been overlooked for a long time. In this paper we prove that such succinctness is not achievable in Euclidean plane, assuming that Cartesian or polar coordinate system is used, the network topology is a planar graph, and the planar embedding is preserved during the process of greedy embedding. Indeed, we provide a counter example to show that in this situation, some coordinates must take ¿(n) bits to represent.\",\n \"Title: Product Code and Recurrent Alternative Decoding for Wireless Image Transmission\\nYear: 2000\\n\\nAbstract: We present a novel channel-coding scheme for image transmission over wireless channels. A key component is the application of product code to the compressed source using recursive systematic code (RSC) and classical convolutional code to combat both random and burst channel errors. Our innovation is the development of recurrent alternative decoding for such product code that leads to high performance transmission. The compressed image data are first arranged into an array of bitstreams so that this array can be coded with convolutional codes and RSC in horizontal and vertical directions respectively. At the receiving end, the data will be alternatively decoded along the two directions. In each iteration, any correctly decoded data in one direction will be used to constrain the decoding in the other direction. This is implemented by using a constrained Viterbi algorithm in which the survival paths are forced to pass through the positions where the bits have already been correctly decoded. With such constraint, the recurrent decoding often converges quickly. Experimental results show that the proposed scheme is able to achieve high performance transmission of compressed image data over severely impaired channels.\",\n \"Title: An Efficient Decoder for Turbo Product Codes with Multi-Error Correcting Codes\\nYear: 2007\\n\\nAbstract: In this paper, Chase decoding algorithm for turbo product codes (TPCs) built with multi-error-correcting codes is investigated. A method is proposed to reduce the decoding of test patterns (TPs) as well as the calculation of syndromes and metrics. In the beginning, syndromes and metrics of the first half of TPs are calculated recursively. After decoding of one TP, according to the error bit positions, other TPs that will have the same decoded codeword are identified and rejected from decoding. In the mean time, if these TPs fall into the range of second half of TPs, their syndromes and metrics need not to be calculated either. Simulations results for TPCs built with eBCH(64,51,6,2) or eBCH(64,45,8,3) are presented to demonstrate the efficiency of the proposed method. Moreover, this method that reduces the inherent redundancy in Chase decoding does not cause any degradation in coding gain.\",\n \"Title: Scene Adaptive Multiple Coding Scheme For Robust Image Transmission\\nYear: 2000\\n\\nAbstract: In this paper, we propose a combined source and channel coding scheme for image transmission over noisy channels. The key component is extracting and preserving the scene information and incorporating it with unequal error protection to combat the channel errors. After hierarchical wavelet decomposition of the image, wavelet coefficients with parent-child relationship are grouped into wavelet blocks and classified according to corresponding scenes in the original image. For each class, spatial neighborhood coefficients in the high frequency subbands are constrained so that the spatially isolated coefficients are removed and clustered coefficients are retained at the same time. All the wavelet blocks in the same class are grouped together and coded using SPIHT algorithm. High source coding efficiency is preserved even though multiple source coded bitstreams are generated since the wavelet tree structure is untact. In order to combat the channel errors, unequal error protection strategy implemented by RCPC/CRC channel coding is designed based on the bit contribution to both PSNR and human visual sensitivity. Finally, a postprocessing method is developed at the receiving end to restore the degradation due to the residual error after channel decoding. Experimental results show that the proposed scheme is indeed able to provide protection for more important bits and more important visual content under noisy transmission environment. In particular, the reconstructed images illustrate consistently better visual quality.\",\n \"Title: A Relay-Coding Matrix for Multi-User Cooperative Communications\\nYear: 2011\\n\\nAbstract: In this paper, we consider a scenario that multiple users transmit data to a common destination node with the help of one relay station. We present one coding matrix that is invertible in the finite field and has maximum information spreading. We analyze the performance based on the input-out weight enumerate function (IOWEF) of the relay coding matrix and show a close match with the results of log-likelihood ratio decoding. The method gives a way to readily determine when relay coding is preferred. Further, since data from each user is generally coded with channel codes, using relay coding also enables turbo decoding that alternates between a multi-user relay decoder and single-user decoders at the destination. We show via simulations that the turbo decoding converges within only two or three iterations, yet indeed provides significant gains compared with a reference relay system without multi-user cooperation.\",\n \"Title: Method of Using BDI Agents to Implement Service-oriented Workflow Mapping in AGWMS\\nYear: 2006\\n\\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is also emerging as one of the most important grid services. Web service composition has been one of the hottest research topics. Grid environment is very dynamic, and the services are shared among many users, it is impossible to optimize the workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible. In this paper, we propose a method of using BDI agents to implement service-oriented workflow mapping in our agent-based grid workflow management system (AGWMS), which helps grid users streamline, manage and monitor their routinely problem solving processes without having to know any details of the underlying complex structure and dynamic state of VOs. BDI agent technology helps the system meet challenges from the grid context. Three types of workflow in AGWMS are denoted as abstract workflow (AW), concrete workflow (CW) and executable workflow (EW). We also propose AW2CW mapping algorithm and CW2EW mapping algorithm to implement service-oriented workflow mapping. Utilization of three workflow types further liberates model designers from sophisticated system details. It also increases the reusability of domain-specific models and improves the fault tolerance of the system\",\n \"Title: Method of using BDI agents to implement service-oriented workflow mapping in AGWMS\\nYear: 2008\\n\\nAbstract: Workflow management is one of the most important parts of ShanghaiGrid, which has a complex service-oriented infrastructure. Because grid environment is very dynamic and services in it are shared among many users, it is impossible to optimise grid workflow from the point of view of execution ahead of time. In fact, one may want to make decisions about the execution locations and the access to a particular data set as late as possible, which is the main objective of grid workflow mapping. In this paper, three types of workflow are denoted as abstract workflow (AW), concrete workflow (CW) and executable workflow (EW). We propose a method of using Belief-desire-intention (BDI) agents to implement service-oriented workflow mapping in the agent-based grid workflow management system (AGWMS) of ShanghaiGrid. BDI agent technology helps the system meet challenges from the grid context. Contract net protocol (CNP) provides a very proper negotiation model for these agents. The problem of workflow mapping has been transferred to the problem of multi-agent negotiation with the help of CNP model in AGWMS. AW2CW and CW2EW mapping algorithms are also given to accomplish service-oriented workflow mapping.\",\n \"Title: Wheelchair Control Based on Multimodal Brain-Computer Interfaces.\\nYear: 2013\\n\\nAbstract: Electroencephalogram (EEG) based brain-computer interfaces (BCIs) for wheelchair control have great value for those with devastating neuromuscular disorders. Although there have been many attempts to implement EEG-based wheelchair control systems by P300, steady state visual evoked potential (SSVEP), and motor imagery (MI) related event-related desynchronization/ synchronization (ERD/ERS), the number of simultaneous control commands in those BCI systems is strictly limited, and those BCI control do not work for a non-negligible portion of users due to the problem of BCI Illiteracy. In this paper, we develop a multimodal BCI based wheelchair control system, the user could employ subject-optimized mental strategies to produce multiple commands to control the wheelchair, which include ERD/ERS, SSVEP, and simultaneous ERD/ERS and SSVEP. It could not only help address \\\"BCI illiteracy\\\", but also provide simultaneous control commands for complex control. Experiment results demonstrate the proposed system is effective and flexible in practical application. © Springer-Verlag 2013.\",\n \"Title: Robust multiple description image coding over wireless networks based on wavelet tree coding, error resilient entropy coding, and error concealment\\nYear: 2008\\n\\nAbstract: In this paper, we propose an integrated robust multiple description coding (MDC) scheme for compressed still images over error-prone channels with both packet loss and random bit errors. Multiple descriptions are first generated independently by using multiple description scalar quantizer (MDSQ). To achieve an excellent error resilient capability for each description, multiple bitstreams are then generated based on wavelet trees along the spatial orientations. The spatial orientation trees in the wavelet domain are individually encoded using SPIHT. Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt error resilient entropy coding (EREC) to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bitstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients. With analysis and experimental results, we have demonstrated how each of these components has contributed to the overall robustness of the proposed transmission of compressed images over wireless channels.\",\n \"Title: Performance analysis of two-hop amplify-and-forward MIMO relaying with transmit antenna selection\\nYear: 2010\\n\\nAbstract: The performance of transmit antenna selection (TAS) in a two-hop amplify-and-forward (AF) MIMO relaying network over Rayleigh-fading channels is analyzed. Assuming that the source, destination are equipped with NS and ND antennas, respectively, and communicate with each other with the help of an NR-antenna relay, we derive closed-form cumulative distribution function (CDF) of received signal-to-noise ratio (SNR), and based on the CDF, we then present outage probability and exact symbol error rate (SER) for the AF MIMO relay channel with TAS. Numerical results that confirm our analysis are also presented in the paper.\",\n \"Title: A Trust Evaluation Method for Supplier Selection\\nYear: 2013\\n\\nAbstract: Trust and reputation systems play important roles in supplier selection, a topic that has been widely investigated from a business and operation point of view. However, we still lack of effective studies on supplier selection with security as the optimal target, which is a very important factor for Information and Communication Technology (ICT) systems. In response, this paper outlines a method that enables people to evaluate the relative and objective trustworthiness of the alternative suppliers. Our analysis is based solely on the original data of the vulnerabilities publicly available from OSVDB and NVD, which are impossible to tamper with. They are then interpreted by an approach that combines the Analytic Hierarchy Process (AHP) and objective analysis that enables the inference of relative trust valuations based on different evaluation indexes. A case study of five well known vendors is demonstrated with qualitative comparison based on visualization of data.\",\n \"Title: ICTNET at Entity Track TREC 2010.\\nYear: 2010\\n\\nAbstract: This paper gives an overview of our work for related entity finding which is proposed in TREC 2010 Entity Track. The goal of the Entity Track is to find the entities relevant to a given query from the web corpus. In this paper, we propose a bipartite graph reinforcement model for entity ranking. As is well known, the entities on the web are embedded not only in the natural language text, but also in the tables and lists. Given a query, both the candidate entities and relevant tables/lists are extracted from web documents. Then the candidate entities extracted from unstructured text are ranked based on a probabilistic model. But the result contains a lot of noise. If some candidate entities are in a relevant table/list, they are more relevant to the given query. And Vice versa, if a table/list contains several candidate entities, it is also more relevant to the query. Based on the above intuition, we construct a bipartite graph and then perform a reinforcement algorithm to re-rank the candidate entities.\",\n \"Title: ICTNET at Entity ELC TREC 2011.\\nYear: 2011\\n\\nAbstract: null\",\n \"Title: Capture the Flag: A Multiplayer Online Game for Phone Users\\nYear: 2005\\n\\nAbstract: This paper explores the concept of using smart phones to facilitate pervasive mixed reality, locationbased, physical and social gaming. The interaction and communication between the virtual and physical worlds are explored and studied using a mixed reality version of the capture-the-flag game. In this game, players from two different paradigms, virtual and real, compete and collaborate in a social gaming environment using mobile devices and network system.\",\n \"Title: A novel product coding and decoding scheme for wireless image transmission\\nYear: 2000\\n\\nAbstract: This paper presents a novel generic channel coding scheme for image transmission over wireless channels. The product code is constructed using one classical convolutional code in one direction and one recursive systematic code (RSC) in the other direction. At the receiving end, the data are alternatively decoded along the two directions. In each iteration, any correctly decoded data in one direction will be used to constrain the decoding along the other direction. The constrained Viterbi decoding algorithm is designed in such a way that the survival paths are forced to pass through the positions where the bits have already been correctly decoded. With such a constraint, we achieve a reduction of candidate paths for the maximum likelihood (ML) decoding as well as a speed up of convergence. Experimental results show that the proposed scheme is able to outperform all existing schemes under some random and bursty error channel conditions.\",\n \"Title: Optimization for image transmission over varying channel with MCMC.\\nYear: 2012\\n\\nAbstract: Existing work in media transmission generally assumes that the channel condition is stationary. However, communication channels are often varying with time in practice. Adaptive design needs frequent feedback for channel updates, which is often impractical due to the complexity and delay. In this article, we design the unequal error protection for image transmission over noisy varying channels based on their distribution functions. Since the channel effect must be marginalized in order to find the appropriate rate allocation, the optimization problem is very complex. We propose to solve this problem using the Markov Chain Monte Carlo (MCMC) method. The cost function is first mapped into a multi-variable probability distribution. Then, with the “detailed balance”, MCMC is designed to generate samples from the mapped stationary probability distribution so that the optimal solution is the one that gives the lowest data distortion. We also show that the rate allocation design considering the channel probability function works better than the design considering the mean value of the channel.\",\n \"Title: Genetic algorithm utilized in cost-reduction driven web service selection\\nYear: 2005\\n\\nAbstract: A single web service is most likely inadequate to serve the customers’ business needs; it takes a selection of various web services composed together to form a business process. The cost is the primary concern of many business processes. In this paper, we propose a new solution using Genetic Algorithm (GA) in cost-reduction driven web service selection. GA is utilized to optimize business process composed of many service agents (SAg), each of which corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process with taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using local service selection strategy.\",\n \"Title: Automatic geographic web service chaining based-on improved and/or graph\\nYear: 2013\\n\\nAbstract: Nowadays, more and more geospatial applications are provided by geographic web service chaining. Because of large quantities of geo-services and user's personality requirement, it needs to consider both functional and quality of service (QoS) capabilities in geo-service chaining. In this paper, we use geospatial web service dependency graph (GWSDG) to represent the dependencies between services and input/output data, then use BGWSCAOG algorithm to generate GWSDG according to use's request automatically. Finally, we use FOGWSC algorithm to find the GWSC with the global optimal QoS. The implementation of a prototype system and the experimental results show that our approach is not only elegant but also efficient.\",\n \"Title: Iterative decoding for the concatenated system of VLC and STTC in presence of channel estimation errors\\nYear: 2007\\n\\nAbstract: For wireless communications with limited bandwidth and fading channels, both source coding and MIMO techniqueare generally desired. In this paper, we consider the receiver design for a concatenated system with reversible variable length code (RVLC) and space time trellis code (STTC). The maximum a posteriori probability (MAP) decoding algorithm is adapted for both component decoders considering the facts that information are in both bit and symbol domains; systematic information are inseparable and the trellis structure of RVLC is non-symmetric. Conversion from the extrinsic information to the a priori information is also designed based on the modulation mode and mapping method. As a result, the decoding results of each component decoder can be utilized by the other component decoder iteratively so as to improve the overall decoding performance. The designed receiver is then tested for both quasi-static at and rapid fading channels when channel information is known to the receiver either perfectly or non-perfectly, which has shown significant improvement over the traditional receiver without iterative decoding.\",\n \"Title: Performance Bounds On Turbo Coded Hybrid Arq\\nYear: 2007\\n\\nAbstract: In this paper, based on the transfer function bounding techniques for turbo codes, we propose performance bounds on turbo coded hybrid automatic repeat request (TC-HARQ) under additive white Gaussian noise (AWGN) channel. The bounds for both Type-I TC-HARQ and segment selective repeat (SSR)-based TC-HARQ are developed in terms of bit error rate (BER), frame error rate (FER), and throughput. The performance predicted by these bounds are compared with simulation results and show close match in high signal to noise ratio (SNR) regions. The proposed bounds therefore provide good estimates on the error correction performance of TC-HARQ in high SNR regions where simulations are difficult to obtain reasonable results.\",\n \"Title: Multiple hierarchical image transmission over wireless channels\\nYear: 1999\\n\\nAbstract: In this paper, we present a multiple hierarchical coding and transmission scheme in which both the fragile structure of set partitioning in hierarchical trees (SPIHT) source coding and the unequal importance of bits in the coded bitstream have been taken into account. Multiple subsampling is applied to split the wavelet coeffcients of the original image source into multiple subsources so that each subsource is a crude representation of the original image. The sequential dependence of coded bitstream is broken. As a result, the error propagation is limited to a single subsource which is also coded with SPIHT to achieve desired coding performance. Cyclic redundancy coder/rate compatible punctured convolutional coder (CRC/RCPC) channel coding has been used to offer unequal error protection (UEP) to the multiple coded bitstreams. In each substream all the bits in the same bit layer are protected with the same channel code. The higher the bit-layer, the more the channel coding protects. Experimented results show that this new scheme has a good error resilient performance over wireless channels with time varying and bursty errors characteristics. In particular the reconstructed images often demonstrate good visual quality\",\n \"Title: Inter-slice Resolution Improvement of Lung 4D-CT via Adaptively Patch Partition and Sparse Representation\\nYear: 2013\\n\\nAbstract: Lung four-dimensional computer tomography (4D-CT) data resolution enhancement is helpful for lung cancer accurate radiotherapy. Sparse representation based algorithm has been proposed to reconstruct the resolution enhancement image, and achieved state-of-art performance. In this paper, based on the sparse representation algorithm, we present an adaptively patch partition approach to divide the slices into adaptively scaled patches. This approach will catch more anatomical nuances and improve the reconstruction. The quad tree-based algorithm is employed in our method to partition the slices. Moreover, a jointly intensity-feature homogeneity is defined to determinate the patch division criterion. The effectiveness of the proposed method is demonstrated by the experiments.\",\n \"Title: Distributed turbo product codes with soft decode-and-forward and power allocation\\nYear: 2013\\n\\nAbstract: In this paper, we consider a cooperative coding system based on the Distributed Turbo Product Codes DTPC with the extended Bose Chaudhuri Hocquenghem eBCH component codes. To deal with the unreliable decoding at the relay and enhance the overall decoding at the destination, we propose and study two techniques including soft information relaying and power allocation. First, at the relay, the Chase II algorithm and syndrome decoding are used to obtain the reliability values of the source data. This soft information is further exploited to generate new soft incremental redundancy for relaying. Second, to alleviate the error propagation, a method of power allocation between the source and relay is proposed. This method turns out to be very effective compared with the optimal solution from exhaustive search. The system performance in various conditions is presented and compared with extensive simulation.\",\n \"Title: Trust in Knowledge Flow Networks\\nYear: 2005\\n\\nAbstract: An ideal knowledge flow network passes right knowledge to the right person at the right time. Trust between knowledge nodes influences the efficiency of knowledge interchange in an organization. This paper presents a trust model for knowledge flow networks based on knowledge interaction experiences. Simulations show that, compared to the approach of randomly routing, the strategy using trust to help construct knowledge flow network is feasible and effective.\",\n \"Title: Power Allocation for Distributed Turbo Product Codes (DTPC)\\nYear: 2010\\n\\nAbstract: In this paper we investigate the effect of power allocation on the performance of the Distributed Turbo Product Code (DTPC) system. We study the error propagation on distributed coding systems when the relay makes erroneous decisions and present a simple power allocation method to alleviate the effect of relay decoding errors on the iterative decoding at the destination. We validate this method with results of an exhaustive search and compare its performance with the fixed power assignments for DTPC system with Decode and Forward (DF) and Soft Decode and Forward (SDF) relaying protocols. Compared to the fixed power assignment, the proposed method for power allocation shows a performance gain of 1.2dB at 10(-4) Bit Error Rate (BER).\",\n \"Title: Diversity order analysis of a sub-optimal transmit antenna selection strategy for non-regenerative MIMO relay channel\\nYear: 2009\\n\\nAbstract: This paper proposes a novel sub-optimal transmit antenna selection (TAS) strategy for non-regenerative half-duplex MIMO relay channel. While antenna selection is a sub-optimal form of beamforming, it still enjoys the advantage of tractable optimization and low feedback overhead. The diversity order of this proposed strategy is derived to prove that it can achieve the full diversity order as the optimal strategy with only a small performance loss. Furthermore, it is shown that our scheme lead to a reduction of complexity in terms of time slots for SNR estimation when the number of the transmit antennas are more than two. Monte Carlo simulation results of outage probability are presented to demonstrate its advantage over the other two conventional TAS schemes.\",\n \"Title: Constrained decoding for turbo-CRC code with high spectral efficient modulation\\nYear: 2005\\n\\nAbstract: In this paper, we propose a constrained decoding algorithm for turbo-CRC codes with high spectral efficient modulation. We follow a data structure adopted in 3GPP in which the large data frame used for turbo coding consists of multiple CRC packets. First, we modify the turbo encoder by introducing an additional interleaver to permute correctly decoded bits at early stages of decoding over the entire frame. Then, we propose a constrained decoding algorithm at the receiver, making use of the information of correctly decoded bits to help the decoding of other bits and reduce the complexity. Experimental results demonstrate the excellent performance of the entire system. In addition, the error localization property inherent in the system may benefit other applications such as ARQ.\",\n \"Title: Joint Source and Space Time Decoding over Fading Channels\\nYear: 2008\\n\\nAbstract: For high data rate communications, variable length codes (VLC) and multiple input multiple output (MIMO) techniques are required in the application layer and the physical layer, respectively. In this paper, we study the joint decoding for systems that consist of reversible VLC (RVLC) as the source codes and recursive space time trellis codes (STTC) as the coded modulation. The maximum a posteriori probability (MAP) decoding algorithm is modified to accommodate issues including the inseparable systematic information, the unsymmetric trellis structure, and information in both bit and symbol domains. Further, by converting extrinsic information based on the modulation mode and the mapping method, iterative information exchange can be performed so as to fully utilize the redundancy in both RVLC and recursive STTC. The performance of the proposed joint decoding is evaluated over both rapid fading and quasi- static flat fading channels, which shows significant improvement in coding gain in comparison with the non-iterative receiver.\",\n \"Title: Differential detection of space-time spreading with two transmit antennas\\nYear: 2006\\n\\nAbstract: A differential detection scheme for space-time spreading with two transmit antennas is proposed. The scheme does not require channel state information at either the transmitter or the receiver. With segmentation and preamble symbols padded at the transmitter, the receiver recovers the information using differential detection. Both phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals are considered. The proposed scheme achieves two-level transmit diversity gain with low complexity and saves the use of channel estimation, while having about 3 dB performance loss as compared to the coherent detection scheme. When multiple receive antennas exist, additional receive diversity gain can be achieved along with the transmit diversity gain. The scheme works fine under block-fading channel as well as slow Rayleigh fading channel, which is a popular scenario for high-rate data communications. The system performance for different segment sizes, channel fading speeds, modulation methods, and numbers of receive antennas is studied through simulations.\",\n \"Title: High performance stream query processing with correlation-aware partitioning\\nYear: 2013\\n\\nAbstract: State-of-the-art optimizers produce one single optimal query plan for all stream data, in spite of such a singleton plan typically being sub-optimal or even poor for highly correlated data. Recently a new stream processing paradigm, called multi-route approach, has emerged as a promising approach for tackling this problem. Multi-route first divides data streams into several partitions and then creates a separate query plan for each combination of partitions. Unfortunately current approaches suffer from severe shortcomings, in particular, the lack of an effective partitioning strategy and the prohibitive query optimization expense. In this work we propose the first practical multi-route optimizer named <u>c</u>orrelation-aware <u>m</u>ulti-<u>r</u>oute stream query optimizer (or CMR) that solves both problems. By exploiting both intra- and inter-stream correlations of streams, CMR produces effective partitions without having to undertake repeated expensive query plan generation. The produced partitions not only are best served by distinct optimal query plans, but also leverage the partition-driven pruning opportunity. Experimental results with both synthetic and real life stream data confirm that CMR outperforms the state-of-the-art solutions up to an order of magnitude in both the query optimization time and the run-time execution performance.\",\n \"Title: Evaluation And Application Of A Hybrid Brain Computer Interface For Real Wheelchair Parallel Control With Multi-Degree Of Freedom\\nYear: 2014\\n\\nAbstract: There have been many attempts to design brain-computer interfaces (BCIs) for wheelchair control based on steady state visual evoked potential (SSVEP), event-related desynchronization/synchronization (ERD/ERS) during motor imagery (MI) tasks, P300 evoked potential, and some hybrid signals. However, those BCI systems cannot implement the wheelchair navigation flexibly and effectively. In this paper, we propose a hybrid BCI scheme based on two-class MI and four-class SSVEP tasks. It cannot only provide multi- degree control for its user, but also allow the user implement the different types of commands in parallel. In order for the subject to learn the hybrid mental strategies effectively, we design a visual and auditory cues and feedback-based training paradigm. Furthermore, an algorithm based on entropy of classification probabilities is proposed to detect intentional control (IC) state for hybrid tasks, and ensure that multi-degree control commands are accurately and quickly generated. The experiment results attest to the efficiency and flexibility of the hybrid BCI for wheelchair control in the real- world.\",\n \"Title: A novel feature fusion approach based on blocking and its application in image recognition\\nYear: 2006\\n\\nAbstract: According to the idea of canonical correlation analysis, a block-based method for feature extraction is proposed. The main process can be explained as follows: extract two groups of feature vectors from different blocks which belong to the same pattern; and then extract their canonical correlation features to form more effective discriminant vectors for recognition. To test this new approach, the experiment is performed on ORL face database and it shows that the recognition rate is higher than that of algorithm adopting single feature.\",\n \"Title: Channel Mean Forwarded Regenerative Cooperative Demodulation in OFDM Systems\\nYear: 2008\\n\\nAbstract: In this paper, we propose a channel mean forwarded (CMF) relay scheme with gammamin-MRC demodulator at the destination for cooperative OFDM systems. For regenerative cooperative communications, i.e., decode-and-forward (DF) scheme, using the classical MRC demodulator, may not give satisfactory system performance since the channel quality of the source-to-relay (S-R) link is not exploited at the destination. On the other hand, near-optimal lambda-MRC and cooperative-MRC (C-MRC) which are proposed to achieve full diversity, require the perfect instantaneous channel state information (CSI) of the S-R link being available at the destination. In our CMF scheme, the S-R channel is based on the classical first-order auto-regression AR(1) models, where the channel mean can be tracked. Based on the forwarded CSI of the S-R link, the destination can use gammamin-MRC demodulator, which combines signals coming from the source-to-relay-to-destination (S-R-D) link and the source- to-destination (S-D) link by appropriately predicted weights to achieve the full diversity. Simulations show that the performance of this CMF scheme is better than the classical MRC scheme. In slow-fading scenarios, the performance of this CMF scheme can approach the one that the perfect square of the channel norm of the S-R link is available at the destination. Even in fast-fading scenarios, the CMF scheme can also achieve better performance than the classical MRC scheme. In addition, we provide the performance of the direct one-hop scheme for fair comparison as well.\",\n \"Title: Analysis on the impact factors of low-rent housing residents' income in Shanghai based on BP neural network.\\nYear: 2011\\n\\nAbstract: Low-rent housing system is the necessary guarantee of building harmonious society and the urgent demand of establishing and perfecting social security system. It has realistically significance to study the low-rent housing by multi-level and multi-angle. Based on the data of income for low-rent housing residents, applying BP neural network model, the quantitative analysis on the influence of income factors of low-rent housing residents in Shanghai was given, and the mechanism of each factor was studied by further analysis. The result showed that BP neural network model could be successful to study the income of Shanghai low-rent housing residents. There are different influences and mechanisms on each factor to the segment income and total income. Furthermore, the top two influential factors on the wage income is the employment and marital status, and transfer income has the closest relationship with sexuality, region and employment status. Therefore, it reflects that the level of employment and social welfare play important roles for the income of low-rent housing residents. © 2011 IEEE.\",\n \"Title: Turbo Codes Based Image Transmission for Channels with Both Random Errors and Packet Loss\\nYear: 2007\\n\\nAbstract: In this paper, we propose an unequal error protection (UEP) framework for progressive image transmission over wireless networks with both random errors and packet loss. By sophisticatedly interleaving each coded frame, the packet loss is converted into randomly punctured bits in a turbo code. Therefore, error control of channels with both types of distortions is equivalent to dealing with random bit errors only through turbo codes with reduced rates. To optimally allocate the overall transmission rate between the source and channel codes, a genetic algorithm (GA) based method is proposed which not only largely reduces the optimization complexity but also gives results close to the brute force search in tested scenarios. Then, we extend the UEP to a product code scheme by adding Reed-Solomon (RS) code across the frames. An efficient rate allocation method for this product code with the use of interleaving is further presented. The effectiveness of the proposed schemes is demonstrated with extensive simulation results.\",\n \"Title: Distributed STBC With Soft Information Relay Based on Gaussian Approximation.\\nYear: 2012\\n\\nAbstract: We consider a system where the source transmits signals to the destination via two-relays where distributed space time block codes (STBC) are used. It is assumed that the signals are coded at the source and decoded at the relays. In the general case, the decoding at relays might not be perfect and hence the soft information is forwarded. Considering the independent Rayleigh channels and using the ...\",\n \"Title: Symbol Detection with Network Coding in Wireless Channels\\nYear: 2013\\n\\nAbstract: For multi-sources transmitting to a common sink with assistance of relays where network coding is used, different symbols may experience different fading and noise levels, and there is a need to calculate the average symbol detection error probability at the receiver. In this letter, we present a method that closely bounds the error performance when log-likelihood ratio (LLR) detection is used. The method integrates two techniques including the union bound based on the bit-level input-output weight enumerate function (IOWEF) in coding and the maximum ratio combining (MRC) in diversity analysis. The method is applicable to any network coding matrix used at relay.\",\n \"Title: Differential Space-Time Spreading With Segment Selective Repeat-Based Automatic Repeat Request\\nYear: 2008\\n\\nAbstract: In this paper, we first propose differential space-time spreading (DSTS) with multiple transmit antennas. With the assumption of no channel state information at either the transmitter or the receiver, the DSTS signal is differentially encoded and decoded. The proposed method achieves full transmit diversity gains. As compared to the coherent space-time spreading (CSTS) method, the proposed scheme has 3-dB performance degradation, but avoids the demand of perfect channel estimation. We then combine DSTS with segment selective repeat (SSR)-based automatic repeat request (ARQ). By utilizing the estimated channel gain of DSTS at the receiver, only the worse corrupted portion of the data is retransmitted upon error to improve efficiency. It is shown that the proposed DSTS with SSR-based ARQ achieves higher throughput than DSTS with Type-I ARQ while maintaining similar bit error rate (BER).\",\n \"Title: Using genetic algorithm to implement cost-driven web service selection\\nYear: 2007\\n\\nAbstract: Web services composition has been one of the hottest research topics. But with the ever-increasing number of functional similar web services being made available on the Internet, there is a need to be able to distinguish them using a set of well-defined Quality of Service (QoS) criteria. The cost is the primary concern of many business processes. This paper proposes a new solution using Genetic Algorithm (GA) to implement cost-driven web service selection. GA is utilized to optimize a business process composed of many service agents (SAgs). Each SAg corresponds to a collection of available web services provided by multiple service providers to perform a specific function. Service selection is an optimization process taking into account the relationships among the services. Better performance has been gotten using GA in the paper than using a local service selection strategy. The global optimal solution might also be achieved with proper GA parameters.\",\n \"Title: ShanghaiGrid Portal: The Current Stage of Building Information Grid Portal\\nYear: 2004\\n\\nAbstract: Grid portal gives a center access point to access Grid applications and resources., Currently the existing Grid portals are mainly designed for computational Grids which put focus on how to view files, submit and monitor jobs. That alleviate the complexity of using the Grid application. The ShanghaiGrid is an Information Grid which puts focus on how to provide various services in Grid environment to public rather than to scientists. In ShanghaiGrid portal the portal information service, workflow service, and transaction service are very important to achieve the goal of building a web interface for citizens to seamlessly and transparently use the Grid services located in ShanghaiGrid environment. This paper reports our current research and implementation of the ShanghaiGrid portal.\",\n \"Title: An ECA-Rule-Based workflow management approach for web services composition\\nYear: 2005\\n\\nAbstract: Composing autonomous Web services to achieve new function, is receiving more and more attention in recent years in several computer science communities. The workflow model is the most important part in Web services composition. However, the existing approaches have difficulties in the process because their complexity. In this paper, we have developed an ECA (Event-Condition-Action)-rule-based workflow management system (EWMS) for Web service composition, which can help users compose Web services conveniently. We also use an image processing application to validate the feasibility and efficiency of our system.\",\n \"Title: Turbo Decoder For Low-Power Ultrawideband Communication Systems\\nYear: 2008\\n\\nAbstract: A new method to reduce the computational complexity of the turbo decoding in ultrawideband (UWB) orthogonal frequency division multiplexing (OFDM) system is proposed. Existing stopping techniques for turbo decoding process using constrained decoding assume fixed signal-to-noise ratio (SNR) for all the OFDM symbol bits so they fail to yield an acceptable bit-error rate (BER) performance in multicarrier systems. In this paper, we propose a bit-level stopping technique for turbo decoding process based on the constrained decoding method. In this technique, we combine the cyclic redundancy check (CRC) with an adaptive threshold on the log likelihood ratio (LLR) on each subcarrier to detect for convergence. The threshold is adaptive in the sense that the threshold on the LLR of a bit is determined by the average SNR of the OFDM symbol and the channel gain of the transmission subcarrier. Results show that when the channel state information (CSI) is used to determine the threshold on LLR, the stopping technique can reduce the computational complexity by about 0.5-2.5 equivalent iterations compared to GENIE turbo without degradation in the BER performance. Copyright (C) 2008 E. A. Obiedat and L. Cao. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.\",\n \"Title: Joint decoding of concatenated VLEC and STTC system\\nYear: 2008\\n\\nAbstract: We consider the decoding of wireless communication systems with both source coding in the application layer and channel coding in the physical layer for high-performance transmission over fading channels. Variable length error correcting codes (VLECs) and space time trellis codes (STTCs) are used to provide bandwidth efficient data compression as well as coding and diversity gains. At the receiver, an iterative joint source and space time decoding scheme are developed to utilize redundancy in both STTC and VLEC to improve overall decoding performance. Issues such as the inseparable systematic information in the symbol level, the asymmetric trellis structure of VLEC, and information exchange between bit and symbol domains have been considered in the maximum a posteriori probability (MAP) decoding algorithm. Simulation results indicate that the developed joint decoding scheme achieves a significant decoding gain over the separate decoding in fading channels, whether or not the channel information is perfectly known at the receiver. Furthermore, how rate allocation between STTC and VLEC affects the performance of the joint source and space-time decoder is investigated. Different systems with a fixed overall information rate are studied. It is shown that for a system with more redundancy dedicated to the source code and a higher order modulation of STTC, the joint decoding yields better performance, though with increased complexity.\",\n \"Title: SH-MDS: A ShanghaiGrid Information Service Model\\nYear: 2004\\n\\nAbstract: Grid computing is becoming a mainstream technology for sharing large-scale resources, accomplishing collaborative tasks and integrating distributed systems. Information Service plays a very important role in Grid Computing Environment. Through information Service Grid applications are able to exploit the knowledge about current grid status and configuration to adapt themselves to changes in heterogeneous, dynamic environments. In this paper, we propose a framework of Information Service based on the testbed ShanghaiGrid. In GT3, the Index Service in MDS can not provide a reliable indexing, while in our framework, using the notification method to contact Grid Services to Index Service to provide a reliable indexing. The information that Information Service should provide according with the ShanghaiGrid is discussed in detail.\",\n \"Title: Interleaved turbo codes protection for progressive image transmission with efficient rate allocation\\nYear: 2007\\n\\nAbstract: Instead of using product codes for progressive image transmission over noisy fading channels, we extend, in this paper, a recently proposed image transmission method by the authors by interleaving each coded packet to fading channels so that the effect of burst error can be converted into the random bit errors. As a result, the design of unequal error protection for fading channel can be unified with the rate compatible punctured turbo (RCPT) codes protection only. We show that a better performance than the product code protection can be obtained for a given channel condition. Furthermore, the proposed method is also insensitive to the channel variation. Some interesting technical components including a Genetic Algorithm (GA) based rate allocation method, using RS codes to break the error floor of the turbo codes are also discussed in the paper. The advantages of the proposed methods have been demonstrated with extensive simulation results.\",\n \"Title: Performance analysis of transmit antenna selection and relay selection in two-hop multiple MIMO relaying\\nYear: 2012\\n\\nAbstract: This paper analyzes cooperative diversity wireless networks with the application of multiple-input multiple-output (MIMO) techniques, using amplify-and-forward (AF) MIMO relaying with transmit antenna selection (TAS)/maximal-ratio combing (MRC) and relay selection (RS). The source, destination, and relays are equipped with multiple antennas, denoted by NS, ND, and NR, respectively. Specifically, the asymptotic performance is analyzed and the derived upper bound and lower bound on the diversity order leads to the conclusion that the diversity order of NSND +NRmin{NS;ND} can be achieved in the cooperative AF MIMO relaying scenario, which depends on the total number of relay antennas rather than the individual number of each relay's antennas. Numerical results that confirm our analysis are also presented in the paper.\",\n \"Title: Interactive Outlier Exploration in Big Data Streams.\\nYear: 2014\\n\\nAbstract: We demonstrate our VSOutlier system for supporting interactive exploration of outliers in big data streams. VSOutlier not only supports a rich variety of outlier types supported by innovative and efficient outlier detection strategies, but also provides a rich set of interactive interfaces to explore outliers in real time. Using the stock transactions dataset from the US stock market and the moving objects dataset from MITRE, we demonstrate that the VSOutlier system enables analysts to more efficiently identify, understand, and respond to phenomena of interest in near real-time even when applied to high volume streams.\",\n \"Title: Analysis of the degree distribution for LT codes\\nYear: 2014\\n\\nAbstract: the first type of practical fountain codes, LT codes are used in various applications. Although the performance of an LT code is determined by the parameters of the Robust Soliton Distribution RSD, this relationship remains largely unclear. In this paper, we analytically study the relationship between the mean degree value of the RSD and the parameters including the spike position and δ in RSD. Then, with obtained properties and simulation results, we further investigate the impact of these parameters on the performance of LT codes.\",\n \"Title: Cross-layer optimization for 3-D video transmission over cooperative relay systems.\\nYear: 2014\\n\\nAbstract: The rate budget constraint and the available instantaneous signal-to-noise ratio of the best relay selection in cooperative systems can dramatically impact the system performance and complexity of video applications, since they determine the video distortion. By taking into account these constrained factors, we first outline the signal model and formulate the system optimization problem. Next, we propose a new approach to cross-layer optimization for 3-D video transmission over cooperative relay systems. We propose procedures for estimation of the end-to-end instantaneous signal-to-noise ratio using an estimate of the available instantaneous signal-to-noise ratios between the source–destination, and source–relay–destination before starting to send the video signal to the best relay and destination. A novel approach using Lagrange multipliers is developed to solve the optimum bit allocation problem. Based on the rate budget constraint and the estimated the end-to-end instantaneous signal-to-noise ratio, the proposed joint source–channel coding (JSCC) algorithm simultaneously assigns source code rates for the application layer, the number of high and low priority packets for the network layer, and channel code rates for the physical layer based on criteria that maximize the quality of video, whilst minimizing the complexity of the system. Finally, we investigate the impact of the estimated the end-to-end instantaneous signal-to-noise ratio on the video system performance and complexity. Experimental results show that the proposed JSCC algorithm outperforms existing algorithms in terms of peak signal-to-noise ratio. Moreover, the proposed JSCC algorithm is found to be computationally more efficient since it can minimize the overall video distortion in a few iterations.\",\n \"Title: Divergence-Based Soft Decision for Error Resilient Decentralized Signal Detection\\nYear: 2014\\n\\nAbstract: In this paper, we consider decentralized detection where the transmission of local soft-decisions of the secondary users (SUs) to the fusion center (FC) is both rate-limited and error-prone. The quantized data to be sent from SUs should not only carry the local information but also need to be resilient to channel errors. With the assumption of independent and identical secondary user observations conditioned on signal hypothesis and binary symmetric channels (BSC) between SUs and the FC, we design local quantizers at a SU, based on two divergence metrics, namely Kullback-Leibler (KL) and Chernoff. Using convex duality, we show that a two-stage algorithm can be developed to take care of the quantization thresholding, codeword assignment, and error resilience. Specifically, we obtain the following results. First, we show that the proposed quantizer obtains increased divergence between the distributions of the demodulated data at the FC, when compared to the maximum entropy quantizer design. We also point out the fallacy of previously reported Gray code assignment to quantized data. Second, the quantizer optimally picks the repetition codeword in the case of “ideal” sensing at the sensors. Similar “channel blind” optimal quantizer design was observed in the literature for single-sensor case. Third, we derive new bit error probability (BEP) wall expression for D-bits soft-quantization, for specified probabilities of errors at the FC. The new result shows whether and when a majority logic rule is optimal at the FC.\",\n \"Title: BER analysis and power allocation for cooperative diversity networks with distributed Alamouti code\\nYear: 2015\\n\\nAbstract: In this paper, we consider the distributed Alamouti code for a cooperative diversity network consisting of a source, a non-regenerative relay, and a destination. While in the first time phase, the source radiates signals to both relay and destination; in the second time phase, the source and the relay cooperatively send signals to the destination by using an Alamouti code. Considering the amplify-and-forward protocol and independent Rayleigh fading, we first derive the exact average bit error rate performance in a single integral expression so that the system performance can be numerically evaluated. Then, based on a new approximation method of the Marcum Q-function, we also give a tight upper bound for the system performance with a summation of a number of series components. We demonstrate through simulation that, in various operation scenarios with different channel quality and types of modulation, the results of the exact bit error rate expression accurately matches the simulation results, and the bound is tighter and more robust than existing approximation methods. Finally, we show that the analytic work also provides a method for the optimal allocation of power between the source and the relay in the second time phase. Copyright © 2013 John Wiley & Sons, Ltd.\",\n \"Title: Name Disambiguation By Collective Classification\\nYear: 2014\\n\\nAbstract: Disambiguating person names in a set of documents (e.g. research papers or Web pages) is a critical problem in many knowledge management applications. The phenomenon of ambiguity will deteriorate the quality of service, such as the scholar searching and expert finding. Despite years of research, this problem remains largely unsolved, where the unknown number of persons with the same name and the information scarcity in documents pose many difficulties and challenges. In this paper, we formalize name disambiguation as a collective classification problem and solve it using a simple yet effective iterative classification algorithm, referred as ICAND (i.e. Iterative Classification Algorithm for Name Disambiguation). Experimental results on researcher dataset show that the proposed approach can significantly outperform several baseline methods.\",\n \"Title: Multiple UAVs hierarchical dynamic task allocation based on PSO-FSA and decentralized auction\\nYear: 2014\\n\\nAbstract: Multi-UAVs dynamic task allocation is a hot issue currently in the field of unmanned combat command and control. The dynamic task allocation problem for unexpected new tasks appear in battle field is the focus of this study. In order to fulfill the requirements of time and communication complexity, firstly, this paper establishes a state information model of UAV and UAV groups based on the grouping of tasks and UAVs. Secondly, this paper propose a mixed dynamic task allocation method to decompose the problem into two low-level problems including group-level task allocation and member-level task allocation, which are solved by using improved PSO-FSA and distributed auction algorithm. Finally, the simulation experiments prove the effectiveness of the algorithm proposed in this paper and that it can reduce the size of dynamic task allocation, which leads to the reduction of time complexity and communication complexity.\",\n \"Title: Detecting moving object outliers in massive-scale trajectory streams\\nYear: 2014\\n\\nAbstract: The detection of abnormal moving objects over high-volume trajectory streams is critical for real time applications ranging from military surveillance to transportation management. Yet this problem remains largely unexplored. In this work, we first propose classes of novel trajectory outlier definitions that model the anomalous behavior of moving objects for a large range of real time applications. Our theoretical analysis and empirical study on the Beijing Taxi and GMTI (Ground Moving Target Indicator) datasets demonstrate its effectiveness in capturing abnormal moving objects. Furthermore we propose a general strategy for efficiently detecting the new outlier classes. It features three fundamental optimization principles designed to minimize the detection costs. Our comprehensive experimental studies demonstrate that our proposed strategy drives the detection costs 100-fold down into practical realm for applications producing high volume trajectory streams to utilize.\",\n \"Title: Personalized paper recommendation in online social scholar system\\nYear: 2014\\n\\nAbstract: This paper presents a practical paper recommender system, which aims to provide personalized research paper recommendations to users within an online social scholar system. As an online recommender system, there are three basic problems we need to tackle: 1) How to formalize and solve the recommendation problem; 2) How to achieve real time recommendation; and 3) How to interact with users. In our work, we take the personalized paper recommendation as a ranking problem with respect to users' research interests, and employ a supervised learning to rank approach to solve the problem. However, most previous learning to rank methods rely on manually labeled training data which are both expensive and limited in size. We propose automatical training data construction by mining the existing large scale academic network, and extract various heterogeneous features for learning. With the learned model, we conduct real time personalized recommendation based on our novel efficient candidate generation approach. In addition, update recommendation is employed to interact with users according to different types of user feedbacks. Finally, we demonstrate the effectiveness of our system by both offline and online evaluation.\",\n \"Title: Cross-Tier Interference Coordination Of Macro Muting Based On Adaptive Cqi Hysteresis In Hspa Heterogeneous Network\\nYear: 2013\\n\\nAbstract: Heterogeneous network (HetNet) has been studied earlier in the context of LTE. But lately, there are also some discussions about HetNet in HSPA. Cross-tier interference (CTI) is an annoying issue to be investigated in the co-channel HSPA HetNet (CHH) scenario. In this paper, we will focus on the downlink CTI problem in CHH and propose a solution to mitigate it. Our scheme involves the macro muting (MM) in which macro NodeB will mute itself at some certain sub-frames to reduce the CTI level in the system. We also enhance the MM scheme by introducing the adaptive CQI hysteresis (ACH) mechanism to avoid the issue that the low power node (LPN) in HetNet may use the improper CQI for transmitting when MM is implemented. Simulation results will show the benefits of our proposed scheme.\",\n \"Title: Architecture approach for ICT supply chain integrity\\nYear: 2013\\n\\nAbstract: With the rapid pace of globalization and outsourcing, supply chain integrity of ICT system is gaining more and more attentions. Integrity of ICT Supply Chain has a slightly different focus from network security. Due to the increasing complexity and formidable cost and timing, it's by no means enough to guarantee the integrity of a modern ICT product through technical testing and vendor screening. An architectural approach, named as Architectural Solution Integration (ASI), has been proposed to improve the supply chain integrity during the topology design stage of ICT systems. In this paper, the architecture design methodology for ASI is proposed. Supplier trust model and supply chain integrity model are established with an algorithm based on ranked attack graph to quantitatively evaluate the integrity of ICT supply chain. Finally, a case study is presented to demonstrate the feasibility of the proposed ICT supply chain integrity model and evaluation algorithm, which are the key elements of the ASI approach.\",\n \"Title: Can Your Friends Predict Where You Will Be?\\nYear: 2014\\n\\nAbstract: With the development of mobile device and wireless networks, user location becomes increasingly valuable in enhancing user experience, system performance and resource allocation. Location-based services have been not only an important perspective of social media, but also a significant contributor to big data analysis. Location prediction, as an interesting topic, can help improve system performance and user experience in location-based services. Existing algorithms on such prediction focus mostly on exploring regularity in users' movement history without taking advantage of the research on social networks, which can provide information on other factors such as peer influence in human mobility. In this work, the aim is to propose an enhanced location prediction model based on both users' mobility patterns and social network information and the proposed algorithm shows a significant improvement over existing ones.\",\n \"Title: Complex event analytics: online aggregation of stream sequence patterns\\nYear: 2014\\n\\nAbstract: Complex Event Processing (CEP) is a technology of choice for high performance analytics in time-critical decision-making applications. Yet while effective technologies for complex pattern detection on continuous event streams have been developed, the problem of scalable online aggregation of such patterns has been overlooked. Instead, aggregation is typically applied as a post processing step after CEP pattern detection, leading to an extremely ineffective solution. In this paper, we demonstrate that CEP aggregation can be pushed into the sequence construction process. Based on this insight our A-Seq strategy successfully aggregates sequence pattern online without ever constructing sequence matches. This drives down the complexity of the CEP aggregation problem from polynomial to linear. We further extend our A-Seq strategy to support the shared processing of concurrent CEP aggregation queries. The A-Seq solution is shown to achieve over four orders of magnitude performance improvement for a wide range of tested scenarios compared to the state-of-the-art solution.\",\n \"Title: Non-Symmetric Decompanding for Improved Performance of Companded OFDM Systems\\nYear: 2007\\n\\nAbstract: Recent work in literature suggests the use of companding transforms to reduce the peak to average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. However, previous performance evaluations assume the availability of infinite bandwidth. In bandlimited conditions, the performance deteriorates as a result of filtering out the out-of-band radiation (OBR). In this letter, we first study the effect of filtering on the performance of various companding techniques. We further propose a simple yet very effective method to overcome this performance degradation. The essential idea is to use companding and decompanding transforms which are not exact inverse of each other. Simulation results show that the proposed scheme significantly outperforms the previous schemes under more realistic channel conditions.\",\n \"Title: Joint Distributed Space-Time Block Coding with Distributed Turbo Product Code (DSTBC-DTPC)\\nYear: 2011\\n\\nAbstract: We propose new joint distributed Space-Time Block Code (STBC)-Distributed Turbo Product Code (DTPC) by generating the vertical parity on the relay and transmitting it to the destination using STBC on the source and relay. We tested our proposed system in a fast fading environment on the three channels connecting the three nodes in the cooperative network. Results show an overall gain that can reach 3.5dB over the non-cooperative system at 10-5 Bit Error Rate (BER).\",\n \"Title: Multi-scale image compressed sensing with optimized transmission\\nYear: 2013\\n\\nAbstract: Existing works in image compressed sensing (CS) often focus on improving the rate-distortion sensing performance but have less consideration of the effect of channel errors on the transmission of CS measurements. This paper explores how the transmission channel errors affect the PSNR performance of the quantized sensing measurements and then increases the resistance of the transmitted data to the noisy channel. We show that the multi-scale block based compressed sensing (MSBCS) using quantization with differential phase code modulation (DPCM), though achieves compression efficiency higher than the regular scalar quantization-based CS, is more vulnerable to channel errors. To improve the error resistance, a method of optimized energy allocation across bit-layers in quantized measurements is presented, which leads to a large PSNR performance improvement for CS data transmission in wireless environment.\",\n \"Title: Distributed Turbo Product Codes over Multiple Relays\\nYear: 2010\\n\\nAbstract: In this paper, we propose a Distributed Turbo Product Code (DTPC) over cooperative network using block Bose Chaudhuri Hochquenghem (BCH) codes as component codes. The source broadcasts extended BCH coded frames to the destination and nearby relays. After decoding the received sequences, each relay constructs a product code by arranging the corrected bit sequences in rows and re-encoding them vertically using BCH as component codes to obtain an Incremental Redundancy (IR) for source's data. To obtain independent vertical parities from each relay in the same code space, different circular interleavers are proposed to interleave BCH rows before reencoding vertically. A modified turbo product decoder to cope with Multiple Vertical Parities (MVP) is used at the destination to iteratively decode the systematic data from the source and the vertical parities generated by the relays. Simulation results in Additive White Gaussian Noise (AWGN) channel using network scenarios show 0.3-0.5dB gain improvement in Bit Error Rate (BER) performance over the non-cooperative Turbo Product Codes (TPC).\",\n \"Title: Soft Incremental Redundancy for Distributed Turbo Product Codes\\nYear: 2010\\n\\nAbstract: In this paper, we propose a distributed turbo product code (DTPC) with soft information relaying over cooperative network using block extended bose Chaudhuri Hochquenghem (EBCH) codes as component codes. The source broadcasts extended EBCH coded frames to the destination and to a preassigned relay. After soft-decoding the received sequences and obtaining the log-likelihood ratio (LLR) values, the relay constructs a product code by arranging the decoded bit sequences in rows and re-encoding them along the columns using a novel soft block encoding technique to obtain soft parity bits with different reliabilities that can be used as soft incremental redundancy (IR) for source's data which is forwarded to the destination. A modified turbo product decoder to cope with the data received over different channels and thus having different reliabilities is used at the destination. We compared the simulation results in additive white Gaussian noise (AWGN) channel using network scenarios with our previous work for decode and forward (DF) DTPC and with non-cooperative case. Results show 0.5 dB gain improvement over the non-cooperative turbo product codes (TPC) at bit error rate (BER) 10-4. In addition, the BER performance is less affected by the decoding errors at the relay.\",\n \"Title: Location dependent optimal relay selection in mobile cooperative environment\\nYear: 2012\\n\\nAbstract: This paper proposes an optimal relay selection criteria based on the location of the relay (0 ≤ λ ≤ 1) relative to source and destination in the cooperative coded system. The proposed optimization algorithm employs distributed turbo product coding technique with hard and soft decoding. It is shown that the link quality depends on the location of the relay which in turn affects overall system Bit Error Rate (BER) performance. The simulation model creates several scenarios for location of intermediate relays when the inter-user channel is experiencing distortion in presence of different Signal to Noise Ratio (SNR)s. It is observed that the link performance degrades as the relay proximity changes with respect to the source and the destination. The relay selection optimization algorithm provides the participating nodes necessary information to select neighboring nodes depending on link quality, thus lowering the BER and increasing the overall network capacity.\",\n \"Title: The Assimilation of Jason-2 Significant Wave Height Data in the North Indian Ocean Using the Ensemble Optimal Interpolation\\nYear: 2016\\n\\nAbstract: A parallel module of data assimilation based on the ensemble optimal interpolation (EnOI) scheme has been developed and implanted into the third-generation spectral wave model NOAA WAVEWATCH III version 3.14 (hereafter NWW3). This paper presents an evaluation of preliminary experiments assimilating satellite altimeter significant wave height (SWH) data into the NWW3-EnOI wave assimilation system. Data from Jason-2 are used mainly for assimilation and from Jason-1 for validation. The target computational domain for the experiments is north of 15° S in the Indian Ocean, which is nested into a global implementation of NWW3. A stationary ensemble of model output SWH sampled during a long time integration was examined first, showing that the ensemble error covariances were of significant flow dependence due to the monsoon climate. Experimental results by the NWW3-EnOI were validated against a number of moored buoys situated in the Bay of Bengal and east of the Arabian Sea. It was found that the assimilation of altimeter SWH reduced the root mean square errors in analyzed SWH by approximately 20%-60% at different validation stations. The improvement in model skill can be retained throughout the forecast period. The assimilation is found to have the greatest impact of the assimilation in areas and seasons where and when sea states are dominated by swells.\",\n \"Title: A DAISY descriptor based multi-view stereo method for large-scale scenes.\\nYear: 2016\\n\\nAbstract: •An improved patch based MVS method by a novel photometric discrepancy function.•Proposed a new corresponding point matching method based on the DAISY descriptor.•Proposed a new photometric discrepancy function based on DAISY descriptor.\",\n \"Title: Online Outlier Exploration Over Large Datasets\\nYear: 2015\\n\\nAbstract: Traditional outlier detection systems process each individual outlier detection request instantiated with a particular parameter setting one at a time. This is not only prohibitively time-consuming for large datasets, but also tedious for analysts as they explore the data to hone in on the appropriate parameter setting and desired results. In this work, we present the first online outlier exploration platform, called ONION, that enables analysts to effectively explore anomalies even in large datasets. First, ONION features an innovative interactive anomaly exploration model that offers an \\\\\\\"outlier-centric panorama\\\\\\\" into big datasets along with rich classes of exploration operations. Second, to achieve this model ONION employs an online processing framework composed of a one time offline preprocessing phase followed by an online exploration phase that enables users to interactively explore the data. The preprocessing phase compresses raw big data into a knowledge-rich ONION abstraction that encodes critical interrelationships of outlier candidates so to support subsequent interactive outlier exploration. For the interactive exploration phase, our ONION framework provides several processing strategies that efficiently support the outlier exploration operations. Our user study with real data confirms the effectiveness of ONION in recognizing \\\\\\\"true\\\\\\\" outliers. Furthermore as demonstrated by our extensive experiments with large datasets, ONION supports all exploration operations within milliseconds response time.\",\n \"Title: Decoding of short LT codes over BIAWGN channels with Gauss-Jordan elimination-assisted belief propagation method\\nYear: 2015\\n\\nAbstract: Belief propagation (BP) algorithm has been widely used for decoding LT codes. It is well known that the premature termination of the BP decoding due to the lack of degree one symbols in the ripple impairs the decoding performance of the code. This problem has been well studied and tackled for binary erasure channel (BEC). However, for binary input additive white Gaussian noise (BIAWGN) channels, the issue still remains unaddressed. In this paper, we propose Gauss-Jordan elimination (GJE)-assisted BP algorithm to address this problem and study its decoding performance for short LT codes over BIAWGN channels. The use of GJE can effectively help the BP decoder continue the decoding process whenever it gets stuck due to the premature termination. Simulation results show that, under the same channel conditions and transmission overheads, the bit error rate (BER) performance obtained using the GJE-assisted BP method significantly outperforms the one obtained using the traditional BP algorithm.\",\n \"Title: On unequal error protection raptor codes\\nYear: 2015\\n\\nAbstract: Raptor codes are the most advanced fountain codes that can provide dynamically changeable code rate and have linear time encoding and decoding. In multimedia communications and different other areas, it is desired that channel codes can provide the property of unequal error protection (UEP). In this paper, we study two methods to provide UEP Raptor codes on the binary erasure channel (BEC): (1) Using UEP precode (2) Using UEP LT codes. With analysis and thorough simulation we compare the two methods and we conclude that applying UEP in the precode can achieve lower bit erasure rate (BER) for both the more important bits (MIB) and less important bits (LIB).\",\n \"Title: A label compression coding approach through maximizing dependence between features and labels for multi-label classification\\nYear: 2015\\n\\nAbstract: Label compression coding strategy aims at multi-label classification problems with high-dimensional and/or sparse label vectors. Without deteriorating classification performance significantly, its efficiency depends on two key aspects: coding raw binary label vectors into real or binary codewords shortly, and decoding binary label vectors from predicted codewords speedily, which reduce the computational costs in training and testing procedures respectively. In this paper, we propose a novel label compression coding method for multi-label classification, which maximizes dependence between features and labels using Hilbert-Schmidt independence criterion and thus considers both feature and label information simultaneously. Via solving an eigenvalue problem, our method results in a small-scale coding matrix and a fast decoding operation. The experiments on ten various bench-mark data sets illustrate that our proposed technique is superior to three existing approaches, including compressive sensing based method, principal label space transformation technique and its conditional version, according to five ranking-based and instance-based performance evaluation measures.\",\n \"Title: Rate and power efficient image compressed sensing and transmission.\\nYear: 2016\\n\\nAbstract: This paper presents a suboptimal quantization and transmission scheme for multiscale block-based compressed sensing images over wireless channels. The proposed method includes two stages: dealing with quantization distortion and transmission errors. First, given the total transmission bit rate, the optimal number of quantization bits is assigned to the sensed measurements in different wavelet sub-bands so that the total quantization distortion is minimized. Second, given the total transmission power, the energy is allocated to different quantization bit layers based on their different error sensitivities. The method of Lagrange multipliers with Karush-Kuhn-Tucker conditions is used to solve both optimization problems, for which the first problem can be solved with relaxation and the second problem can be solved completely. The effectiveness of the scheme is illustrated through simulation results, which have shown up to 10 dB improvement over the method without the rate and power optimization in medium and low signal-to-noise ratio cases. (C) 2016 SPIE and IS&T\",\n \"Title: Multi-query outlier detection over data streams: poster.\\nYear: 2016\\n\\nAbstract: Real-time analytics of anomalous phenomena on streaming data typically relies on processing a large variety of continuous outlier detection requests, each configured with different parameter settings. The processing of such complex outlier analytics workloads is resource consuming due to the algorithmic complexity of the outlier mining process. In this work we propose a sharing-aware multi-query execution strategy for outlier detection on data streams called SOP. The key insight of SOP is to transform the problem of handling a multi-query outlier analytics workload into a single-query skyline computation problem. SOP achieves minimal utilization of both computational and memory resources for the processing of these complex outlier analytics workload.\",\n \"Title: Sharing-Aware Outlier Analytics over High-Volume Data Streams.\\nYear: 2016\\n\\nAbstract: Real-time analytics of anomalous phenomena on streaming data typically relies on processing a large variety of continuous outlier detection requests, each configured with different parameter settings. The processing of such complex outlier analytics workloads is resource consuming due to the algorithmic complexity of the outlier mining process. In this work we propose a sharing-aware multi-query execution strategy for outlier detection on data streams called SOP. A key insight of SOP is to transform the problem of handling a multi-query outlier analytics workload into a single-query skyline computation problem. We prove that the output of the skyline computation process corresponds to the minimal information needed for determining the outlier status of any point in the stream. Based on this new formulation, we design a customized skyline algorithm called K-SKY that leverages the domination relationships among the streaming data points to minimize the number of data points that must be evaluated for supporting multi-query outlier detection. Based on this K-SKY algorithm, our SOP solution achieves minimal utilization of both computational and memory resources for the processing of these complex outlier analytics workload. Our experimental study demonstrates that SOP consistently outperforms the state-of-art solutions by three orders of magnitude in CPU time, while only consuming 5% of their memory footprint - a clear win-win. Furthermore, SOP is shown to scale to large workloads composed of thousands of parameterized queries.\",\n \"Title: Hard decision based distributed detection in multi-sensor system over noise correlated sensing channels\\nYear: 2016\\n\\nAbstract: In spite of the spectrum sensing importance, small part of the literature deals with the case of dependency between sensors' observations. In this paper, Bayes criterion for minimizing the probability of error (Pe) is used to find the distributed decision rule at each sensor in a binary hypothesis multi-sensor system, while considering the correlation over the sensing channels. This paper proposes a new, simple, yet efficient algorithm to find the local decision rules to achieve the objective of minimizing the Pe. Upon receiving the signal, each sensor sends a local hard decision to the fusion center (FC). The FC then generates a global decision using the K-out-of-N majority rule. The derived problem formulation and the proposed algorithm can be used with any joint probability density functions and with any odd number of sensors. The proposed framework also accounts for the path attenuation effect on the global decision. The results show the effectiveness and validity of the proposed framework in practical sensor systems.\",\n \"Title: Divergence and Bayes error based soft decision for decentralized signal detection of correlated sensor data\\nYear: 2016\\n\\nAbstract: In decentralized cooperative sensing for cognitive radio, a few secondary users (SUs) sense the spectrum, process individual observation and then pass quantized data to the fusion center (FC), where the decision on signal present hypothesis or signal absent hypothesis is made. When the reporting channels between SUs and the FC are bandlimited and error prone, a quantization scheme was proposed recently based on divergence measures for independent observations. In this paper, we extend the design of quantizers to correlated sensor data. With the assumption that two SUs' observations are jointly distributed as bivariate Gaussian with identical marginals, we design quantizers based on both divergence measures and the Bayes error. Our simulation results demonstrate that a quantizer designed with the knowledge of known joint distributions outperform the quantizer designed with independent sensor data assumption. Thus, it is important to account for correlation in the quantizer design in distributed cooperative sensing.\",\n \"Title: A Non-linear Label Compression Coding Method Based on Five-Layer Auto-Encoder for Multi-label Classification.\\nYear: 2016\\n\\nAbstract: In multi-label classification, high-dimensional and sparse binary label vectors usually make existing multi-label classifiers perform unsatisfactorily, which induces a group of label compression coding (LCC) techniques particularly. So far, several linear LCC methods have been introduced via considering linear relations among labels. In this paper, we extend traditional three-layer auto-encoder to construct a five-layer one (i.e., five-layer symmetrical neural network), and then apply the training principle in extreme learning machine to determine all network weights. Therefore, a non-linear LCC approach is proposed to capture non-linear relations of labels, where the first three-layer network is regarded as a encoder and the last two layers act as a decoder. The experimental results on three benchmark data sets show that our proposed method performs better than four existing linear LCC methods according to five performance measures.\",\n \"Title: Prediction of Virality Timing Using Cascades in Social Media.\\nYear: 2016\\n\\nAbstract: Predicting content going viral in social networks is attractive for viral marketing, advertisement, entertainment, and other applications, but it remains a challenge in the big data era today. Previous works mainly focus on predicting the possible popularity of content rather than the timing of reaching such popularity. This work proposes a novel yet practical iterative algorithm to predict virality timing, in which the correlation between the timing and growth of content popularity is captured by using its own big data naturally generated from users’ sharing. Such data is not only able to correlate the dynamics and associated timings in social cascades of viral content but also can be useful to self-correct the predicted timing against the actual timing of the virality in each iterative prediction. The proposed prediction algorithm is verified by datasets from two popular social networks—Twitter and Digg—as well as two synthesized datasets with extreme network densities and infection rates. With about 50% of the required content virality data available (i.e., halfway before reaching its actual virality timing), the error of the predicted timing is proven to be bounded within a 40% deviation from the actual timing. To the best of our knowledge, this is the first work that predicts content virality timing iteratively by capturing social cascades dynamics.\",\n \"Title: Symmetric Integer Matrices Having Integer Eigenvalues.\\nYear: 2016\\n\\nAbstract: We provide characterization of symmetric integer matrices for rank at most 2 that have integer spectrum and give some constructions for such matrices of rank 3. We also make some connection between Hanlon’s conjecture and integer eigenvalue problem.\",\n \"Title: Complex singular value decomposition based stereoscopic image quality assessment\\nYear: 2016\\n\\nAbstract: Designing a reliable and generic perceptual quality metric is a challenging issue in three-dimensional (3D) visual signal processing. Due to the limited knowledge on 3D perceptual, it is difficult to fuse the visual information of left and right views in an effective way. In this paper, we propose a complex singular value decomposition (CSVD) based stereoscopic image quality assessment (SIQA) metric. First, the corresponding blocks of the left/right view are grouped into complex representation (CR) block through the scale-invariant feature transform (SIFT) view matching process. Then we compute the CSVD coefficients of each CR block. Final, a CSVD based quality pooling stage is employed to predict the final visual quality of the distorted 3D image. Experimental results demonstrate that the proposed metric has good consistency with 3D perception of human.\",\n \"Title: Outlier Detection over Massive-Scale Trajectory Streams.\\nYear: 2017\\n\\nAbstract: The detection of abnormal moving objects over high-volume trajectory streams is critical for real-time applications ranging from military surveillance to transportation management. Yet this outlier detection problem, especially along both the spatial and temporal dimensions, remains largely unexplored. In this work, we propose a rich taxonomy of novel classes of neighbor-based trajectory outlier definitions that model the anomalous behavior of moving objects for a large range of real-time applications. Our theoretical analysis and empirical study on two real-world datasets—the Beijing Taxi trajectory data and the Ground Moving Target Indicator data stream—and one generated Moving Objects dataset demonstrate the effectiveness of our taxonomy in effectively capturing different types of abnormal moving objects. Furthermore, we propose a general strategy for efficiently detecting these new outlier classes called the <underline>m</underline>inimal <underline>ex</underline>amination (MEX) framework. The MEX framework features three core optimization principles, which leverage spatiotemporal as well as the predictability properties of the neighbor evidence to minimize the detection costs. Based on this foundation, we design algorithms that detect the outliers based on these classes of new outlier semantics that successfully leverage our optimization principles. Our comprehensive experimental study demonstrates that our proposed MEX strategy drives the detection costs 100-fold down into the practical realm for applications that analyze high-volume trajectory streams in near real time.\",\n \"Title: Discovering Evolving Moving Object Groups from Massive-Scale Trajectory Streams\\nYear: 2017\\n\\nAbstract: The increasing pervasiveness of object tracking technologies leads to huge volumes of spatio-temporal data collected in the form of trajectory streams. The discovery of useful group patterns from moving objects' movement behaviors in trajectory streams is critical for real time applications ranging from transportation management to military surveillance. In this work we propose a novel type of group pattern, called evolving group, which models the unusual group events of moving objects that travel together within density connected clusters in evolving streaming trajectories. Our theoretical analysis and empirical study on the Beijing Taxi data demonstrate its effectiveness in capturing development, evolution and trend of group events of moving objects in streaming context. Furthermore, we propose a discovery framework that efficiently supports online detection of evolving groups over massive-scale trajectory streams using sliding window. It contains three phases along with a set of novel optimization techniques designed to minimize the computation costs. Our comprehensive empirical study demonstrates that our discovery framework is effective and efficient on real-world high volume trajectory streams.\",\n \"Title: Soft-decision based distributed detection over correlated sensing channels\\nYear: 2017\\n\\nAbstract: This paper proposes a new framework that performs spectrum sensing in soft decision based distributed detection systems while considering correlated sensors' readings. The main contribution is formulating the problem into a nonlinear integer programming problem for which the genetic algorithm is further applied to find a suboptimal solution. This framework is able to handle both soft and hard decisions while assuming correlation for any number of sensors, and hence largely extends the scenarios being considered in previous works. The results show that our scheme outperforms previous schemes and approaches the centralized detection scheme performance in terms of probability of error.\",\n \"Title: To share or not to share: comparing burst buffer architectures\\nYear: 2017\\n\\nAbstract: Modern high performance computing platforms employ burst buffers to overcome the I/O bottleneck that limits the scale and efficiency of large-scale parallel computations. Currently there are two competing burst buffer architectures. One is to treat burst buffers as a dedicated shared resource, The other is to integrate burst buffer hardware into each compute node. In this paper we examine the design tradeoffs associated with local and shared, dedicated burst buffer architectures through modeling. By seeding our simulation with realistic workloads, we are able to systematically evaluate the resulting performance of both designs. Our studies validate previous results indicating that storage systems without parity protection can reduce overall time to solution, and further determine that shared burst buffer organizations can result in a 3.5× greater average application I/O throughput compared to local burst buffer configurations.\",\n \"Title: Distributed Local Outlier Detection in Big Data\\nYear: 2017\\n\\nAbstract: In this work, we present the first distributed solution for the Local Outlier Factor (LOF) method -- a popular outlier detection technique shown to be very effective for datasets with skewed distributions. As datasets increase radically in size, highly scalable LOF algorithms leveraging modern distributed infrastructures are required. This poses significant challenges due to the complexity of the LOF definition, and a lack of access to the entire dataset at any individual compute machine. Our solution features a distributed LOF pipeline framework, called DLOF. Each stage of the LOF computation is conducted in a fully distributed fashion by leveraging our invariant observation for intermediate value management. Furthermore, we propose a data assignment strategy which ensures that each machine is self-sufficient in all stages of the LOF pipeline, while minimizing the number of data replicas. Based on the convergence property derived from analyzing this strategy in the context of real world datasets, we introduce a number of data-driven optimization strategies. These strategies not only minimize the computation costs within each stage, but also eliminate unnecessary communication costs by aggressively pushing the LOF computation into the early stages of the DLOF pipeline. Our comprehensive experimental study using both real and synthetic datasets confirms the efficiency and scalability of our approach to terabyte level data.\",\n \"Title: Scalable Top-n Local Outlier Detection\\nYear: 2017\\n\\nAbstract: Local Outlier Factor (LOF) method that labels all points with their respective LOF scores to indicate their status is known to be very effective for identifying outliers in datasets with a skewed distribution. Since outliers by definition are the absolute minority in a dataset, the concept of Top-N local outlier was proposed to discover the n points with the largest LOF scores. The detection of the Top-N local outliers is prohibitively expensive, since it requires huge number of high complexity k-nearest neighbor (kNN) searches. In this work, we present the first scalable Top-N local outlier detection approach called TOLF. The key innovation of TOLF is a multi-granularity pruning strategy that quickly prunes most points from the set of potential outlier candidates without computing their exact LOF scores or even without conducting any kNN search for them. Our customized density-aware indexing structure not only effectively supports the pruning strategy, but also accelerates the $k$NN search. Our extensive experimental evaluation on OpenStreetMap, SDSS, and TIGER datasets demonstrates the effectiveness of TOLF - up to 35 times faster than the state-of-the-art methods.\",\n \"Title: MARAS: Signaling Multi-Drug Adverse Reactions\\nYear: 2017\\n\\nAbstract: There is a growing need for computing-supported methods that facilitate the automated signaling of Adverse Drug Reactions (ADRs) otherwise left undiscovered from the exploding amount of ADR reports filed by patients, medical professionals and drug manufacturers. In this research, we design a Multi-Drug Adverse Reaction Analytics Strategy, called MARAS, to signal severe unknown ADRs triggered by the usage of a combination of drugs, also known as Multi-Drug Adverse Reactions (MDAR). First, MARAS features an efficient signal generation algorithm based on association rule learning that extracts non-spurious MDAR associations. Second, MARAS incorporates contextual information to detect drug combinations that are strongly associated with a set of ADRs. It groups related associations into Contextual Association Clusters (CACs) that then avail contextual information to evaluate the significance of the discovered MDAR Associations. Lastly, we use this contextual significance to rank discoveries by their notion of interestingness to signal the most compelling MDARs. To demonstrate the utility of MARAS, it is compared with state-of-the-art techniques and evaluated via case studies on datasets collected by U.S. Food and Drug Administration Adverse Event Reporting System (FAERS).\",\n \"Title: NTIRE 2017 Challenge on Single Image Super-Resolution: Methods and Results.\\nYear: 2018\\n\\nAbstract: This paper reviews the first challenge on single image super-resolution (restoration of rich details in an low resolution image) with focus on proposed solutions and results. A new DIVerse 2K resolution image dataset (DIV2K) was employed. The challenge had 6 competitions divided into 2 tracks with 3 magnification factors each. Track 1 employed the standard bicubic downscaling setup, while Track 2 had unknown downscaling operators (blur kernel and decimation) but learnable through low and high res train images. Each competition had similar to 100 registered participants and 20 teams competed in the final testing phase. They gauge the state-of-the-art in single image super-resolution.\",\n \"Title: On the performance of LT codes over BIAWGN channel\\nYear: 2016\\n\\nAbstract: Luby transform (LT) codes are defined by degree distribution functions of encoded symbols. In erasure channels, good degree distribution functions should prevent the ripple of degree-one symbols from vanishing until the successful termination of decoding process. In this paper, we show that for binary input additive white Gaussian noise (BIAWGN) channels, performance of LT codes also depends on the time at which source nodes in the decoding graph of the codes start receiving non-zero log-likelihood ratio (LLR) values. We show that source nodes can be categorized based on this time, and those in lower categories, i.e., those source nodes updated with non-zero LLR values at earlier iterations have higher probability of being decoded correctly. We theoretically derive formulas that can find the percentages of source nodes in each category for any given degree distribution function. We finally show that by increasing the number of source nodes in the lower categories, the bit error rate (BER) performance of LT codes can be drastically improved. This work provides a new perspective for the performance and design of such codes for BIAWGN channels.\",\n \"Title: Improved decoding for Raptor codes with short block-lengths over BIAWGN channel\\nYear: 2016\\n\\nAbstract: Decoding of Raptor codes consists of decoding of both the LT part and the precode part of the codes. When LT decoding is performed, a scenario may arise where the message passing-based decoding process is unable to provide non-zero log-likelihood ratio (LLR) updates to a fraction of input symbols even if it is mathematically possible to do so. The problem is even more critical for codes with short block-lengths and for smaller overheads. We show that this problem degrades the overall decoding performance of Raptor codes over binary input additive white Gaussian noise (BIAWGN) channel. To combat this problem, the Gauss-Jordan elimination (GJE) is used to assist decoding so that the decoder can continuously provide non-zero LLR updates to all the input symbols connected in the decoding graph. Through simulation results we show that the GJE-assisted method provides significantly better bit error rate (BER) performance of Raptor codes than the traditional method across a wide range of signal to noise ratio (SNR) and transmission overheads.\",\n \"Title: Interactive Analytics System for Exploring Outliers.\\nYear: 2017\\n\\nAbstract: ONION is the first system with rich interactive support for efficiently analyzing outliers. ONION features an innovative exploration model that offers an \\\"outlier-centric panorama'' into big datasets. The ONION system is composed of an offline preprocessing phase followed by an online exploration phase that supports rich classes of novel exploration operations. As our demonstration illustrates, this enables analysts to interactively explore outliers at near real-time speed even over large datasets. We demonstrate ONION's capabilities with urban planning applications use cases on the Open Street Maps dataset.\",\n \"Title: Combined-chain nested sampling for efficient Bayesian model comparison.\\nYear: 2017\\n\\nAbstract: Model comparison problems arise in many fields of science and engineering, including signal processing. In these problems, we wish to quantify how well each of a set of possible models describes a set of observations. Many numerical techniques exist to perform model comparison, but this paper focuses on nested sampling, which is a numerical integration algorithm for evaluating probabilities of models. The original formulation of nested sampling is a strictly sequential algorithm. Most modern advances in computing are via parallel processing, however, and we therefore present a novel method for parallelizing nested sampling. This paper sets out the mathematical foundation for this parallelization, as well as ideas for implementing it. Three examples demonstrate the effectiveness of the present parallel technique in realistic scientific and engineering data analysis problems.\",\n \"Title: A Study Of Qualitative Knowledge-Based Exploration For Continuous Deep Reinforcement Learning\\nYear: 2017\\n\\nAbstract: As an important method to solve sequential decision-making problems, reinforcement learning learns the policy of tasks through the interaction with environment. But it has difficulties scaling to large-scale problems. One of the reasons is the exploration and exploitation dilemma which may lead to inefficient learning. We present an approach that addresses this shortcoming by introducing qualitative knowledge into reinforcement learning using cloud control systems to represent 'if-then' rules. We use it as the heuristics exploration strategy to guide the action selection in deep reinforcement learning. Empirical evaluation results show that our approach can make significant improvement in the learning process.\",\n \"Title: Pivot-Based Distributed K-Nearest Neighbor Mining.\\nYear: 2017\\n\\nAbstract: k-nearest neighbor (kNN) search is a fundamental data mining task critical to many data analytics methods. Yet no effective techniques to date scale kNN search to large datasets. In this work we present PkNN, an exact distributed method that by leveraging modern distributed architectures for the first time scales kNN search to billion point datasets. The key to the PkNN strategy is a multi-round kNN search that exploits pivot-based data partitioning at each stage. This includes an outlier-driven partition adjustment mechanism that effectively minimizes data duplication and achieves a balanced workload across the compute cluster. Aggressive data-driven bounds along with a tiered support assignment strategy ensure correctness while limiting computation costs. Our experimental study on multi-dimensional real-world data demonstrates that PkNN achieves significant speedup over the state-of-the-art and scales effectively in data cardinality. Code and data related to this chapter are available at: http://solar-10.wpi.edu/cakuhlman/ PkNN.\",\n \"Title: Protocol Design for Content Transfer in Deep Space Network.\\nYear: 2017\\n\\nAbstract: Space communications feature large round-trip time (RTT) delays and highly variable data error rates. In this paper, we propose a new content transfer protocol based on RaptorQ codes and turbo codes, incorporated with a real-time channel prediction model, to maximize file transfer from space vehicles to Earth stations. While turbo codes are used to correct channel errors, RaptorQ codes are applied to eliminate the need for negative-acknowledgment (NAK) of the loss of any specific packet. To reduce the effect of channel variation, a practical signal-to-noise ratio (SNR) prediction model that is used to periodically adjust the turbo encoder in distant source spacecraft is developed. This new protocol, termed as the dynamic code selection method (DCSM), is compared with two other methods: a turbo codes based genie method (upper bound of DCSM performance) assuming that the channel condition is perfectly known in advance and a static method in which a fixed turbo encoder is used throughout each communication pass. Simulation results demonstrate that the genie and the new DCSM methods can increase telemetry channel throughput by about 47% and 46%, respectively, compared to the static method. In addition, throughput performance using the DCSM is about 99% of the upper bound achieved with the genie method.\",\n \"Title: Study Of Subjective And Objective Quality Assessment For Screen Content Images\\nYear: 2017\\n\\nAbstract: In this paper, we present the results of a recent large-scale subjective study of image quality on a collection of screen contents distorted by a variety of application-relevant processes. With the development of multi-device interactive multimedia applications, metrics to predict the visual quality of screen content images (SCIs) as perceived by subjects are becoming fundamentally important. For developing the objective image quality assessment (IQA) method, there is a need for large-scale public database with diversity of distorted types and scene contents, and available subjective scores of distorted SCIs. The resulting Immersive Media Laboratory screen content image quality database (IML-SCIQD) contains 1250 distorted SCIs from 25 reference SCIs with 10 distortion types. Each image was rated by 35 human observers, and the different mean opinion scores (DMOS) were obtained after data processing. The performance comparison of 17 state-of-the-arts, publicly available IQA algorithms are evaluated on the new database. The database will be available online in our project website.\",\n \"Title: On the Design of Serially Concatenated LDGM Codes for BIAWGN Channels.\\nYear: 2018\\n\\nAbstract: In this paper, we first prove a necessary condition for the successful decoding of serially concatenated low-density generator-matrix (SCLDGM) codes under sum-product (SP) decoding in binary input additive white Gaussian noise (BIAWGN) channels. We show that the inner decoder of such codes must at least produce a certain bit error rate (BER) called critical BER in order for the outer decoder to achieve successful decoding. We verify this condition by providing asymptotic curves for the SCLDGM codes using discretized density evolution (DDE) method. We finally propose a DDE-based optimization approach that utilizes the concept of the critical BER to construct optimized SCLDGM codes that approach the Shannon limit. We also present asymptotic and simulation results of our optimized codes that verify the effectiveness of the proposed optimization approach.\",\n \"Title: Asymptotic analysis and optimization design of physical layer systematic rateless codes\\nYear: 2018\\n\\nAbstract: In this paper, we first provide the asymptotic analysis of systematic version of Luby transform (LT) and Raptor codes over binary input additive white Gaussian noise (BIAWGN) channel using discretized density evolution (DDE). We then use a DDE-based optimization approach to obtain optimized output degree distributions for the systematic Raptor (SR) codes of various realized code-rates. We finally provide the decoding thresholds and simulation results showing that our optimized SR codes largely outperform the traditional SR codes in BIAWGN channel.\",\n \"Title: How to foster innovation: A data-driven approach to measuring economic competitiveness.\\nYear: 2017\\n\\nAbstract: Innovation is a key factor driving economic growth in countries worldwide. However, innovation is hard to define and, therefore, even harder to measure. To help policy makers and business leaders better understand how to foster innovation, we need robust ways to quantify innovation at local and global scales. In this work, we use a data-driven, machine-learning approach for measuring innovation. A...\",\n \"Title: Analysis and Design of Physical Layer Raptor Codes.\\nYear: 2018\\n\\nAbstract: In this letter, we first provide the asymptotic analysis of Raptor codes over binary input additive white Gaussian noise channels using discretized density evolution (DDE). We show that the Raptor codes of various realized code-rates using the same output degree distribution perform within 0.4-dB to the Shannon limit. We then prove a necessary condition for the successful decoding of such codes and use it with a DDE-based optimization method to obtain optimized Raptor codes with further improvement in decoding thresholds.\",\n \"Title: Optimal Channel Set Selection For Ssvep-Based Bci Using Spatial Temporal Correlation\\nYear: 2017\\n\\nAbstract: In SSVEP-based BCI, portability has great influence on the popularization. Reducing redundant channels is an effective way to upgrade the portability. This paper presents a novel method that utilizes spatial temporal correlation (STC) to optimize the selection of channel set. Average accuracy was obtained at 85.28% using STC, improved by 1.11%, proving that STC method is effective to find out the most useful channels in detecting SSVEP components. And the optimal set, chosen by STC, yield an average accuracy at 83.34%, means that STC can help BCI improve the convenience by reducing the number of channels without shrinking the performance sharply and provide guidance for further SSVEP-based BCI.\",\n \"Title: Fiber Bragg Grating-Based Triaxial Force Sensor With Parallel Flexure Hinges.\\nYear: 2018\\n\\nAbstract: During cardiac surgery, the excessive or insufficient contact force between the tip of catheter and heart tissue will lead to the cardiac penetration or noneffective ablative lesion. Usually, the surgeon can only estimate the force at the distal end roughly from their experience by operating the catheter's proximal handle. In this paper, we design a fiber Bragg grating-based triaxial force sensor ...\",\n \"Title: Short time Fourier transformation and deep neural networks for motor imagery brain computer interface recognition.\\nYear: 2018\\n\\nAbstract: Motor imagery (MI) is an important control paradigm in the field of brain-computer interface (BCI), which enables the recognition of personal intention. So far, numerous methods have been designed to classify EEG signal features for MI task. However, deep neural networks have been seldom applied to analyze EEG signals. In this study, two novel kinds of deep learning schemes based on convolutional neural networks (CNN) and Long Short-Term Memory (LSTM) were proposed for MI-classification. The frequency domain representations of EEG signals were obtained using short time Fourier transform (STFT) to train models. Classification results were compared between conventional algorithm, CNN, and LSTM models. Compared with two other methods, CNN algorithms had shown better performance. These conclusions verified that CNN method was promising for MI-based BCIs.\",\n \"Title: Infrared Small Target Detection Based on Flux Density and Direction Diversity in Gradient Vector Field.\\nYear: 2018\\n\\nAbstract: The existing small target detection methods may suffer serious false alarm rate and low probability of detection in the situation of intricate background clutter. To cope with this problem, a novel small target detection method is proposed in this paper. Initially, the infrared image is transformed to the infrared gradient vector field (IGVF), where some new distinctive characters of the target an...\",\n \"Title: SWIFT: Mining Representative Patterns from Large Event Streams.\\nYear: 2018\\n\\nAbstract: Event streams generated by smart devices common in modern Internet of Things applications must be continuously mined to monitor the behavior of the underlying system. In this work, we propose a stream pattern mining system for supporting online IoT applications. First, to solve the pattern explosion problem of existing stream pattern mining strategies, we now design pattern semantics that continuously produce a compact set of patterns that max-imumly compresses the dynamic data streams, called MDL-based Representative Patterns (MRP). We then design a one-pass SWIFT approach that continuously mines the up-to-date MRP pattern set for each stream window upon the arrival or expiration of individual events. We show that SWIFT is guaranteed to select the update operation for each individual incoming event that leads to the most compact encoding of the sequence in the current window. We further enhance SWIFT to support batch updates, called B-SWIFT. B-SWIFT adopts a lazy update strategy that guarantees that only the minimal number of operations are conducted to process an incoming event batch for MRP pattern mining. Evaluation by our industry lighting lab collaborator demonstrates that SWIFT successfully solves their use cases and finds more representative patterns than the alternative approaches adapting the state-of-the-art static representative pattern mining methods. Our experimental study confirms that SWIFT outperforms the best existing method up to 50% in the compactness of produced pattern encodings, while providing a 4 orders of magnitude speedup.\",\n \"Title: Decentralized Detection of Signals with Joint Clayton Copula Distribution Model\\nYear: 2018\\n\\nAbstract: This paper considers a decentralized detection system for a binary hypothesis testing problem. The sensor signals are marginally Gaussian distributed with θ-parameter Clayton copula joint distribution. Boolean functions of two variables and likelihood ratio test at the fusion center are considered to generate binary global decisions. The exhaustive search and the genetic algorithms are proposed to provide the local sensor decision rules in each scenario such that the probability of error at the fusion center is minimized. The main purpose of this paper is to study the probability of error behavior of the proposed detection systems in a correlated environment characterized by a joint Clayton copula distribution. The results show that in a correlated environment a sound detection system should be characterized by the likelihood ratio test at the fusion center and multiple-threshold decisions at the sensors.\",\n \"Title: Blind channel estimation and equalization using Viterbi algorithms\\nYear: 2002\\n\\nAbstract: In this paper, a trellis based blind channel estimation and equalization technique is presented. First, blind channel estimation is accomplished by incorporating a list parallel Viterbi algorithm with the least mean square (LMS) updating approach. In this operation, multiple trellis mappings are preserved and ranked in terms of path metrics. Equivalently, multiple channel estimates are maintained and updated once a single symbol is received. Second, at a certain point, which is determined by the evolution of path metrics and the linear constraint possessed in the trellis mapping, only the best channel estimate is maintained. Third, this channel estimate is adopted to construct the whole trellis that is used by a conventional adaptive Viterbi algorithm. Signal detection and further channel updating are then conducted alternatively. To alleviate the noise impact, a small delay is introduced before the feedback of detected symbols to further update the channel estimate. Simulation has shown the overall good performance of the proposed scheme in terms of mean square error (MSE) convergence of the channel estimation, stability to the initial channel guess, and computational complexity etc.\",\n \"Title: Planning enhanced grid workflow management system based on agent\\nYear: 2005\\n\\nAbstract: Grid computing is becoming a mainstream technology for large-scale distributed resource sharing and system integration. Workflow management is emerging as one of the most important grid services. In this paper, we present a planning enhanced grid workflow management system based on agent (AGWMS). AGWMS has a four-layer architecture. The agent layer makes the system more robust, flexible and intelligent. Artificial intelligence (AI) planning technology is utilized in the system to build the agent plans automatically. The adapter layer makes it easy that AGWMS invokes external applications. Our planning enhanced AGWMS is a novel one.\",\n \"Title: Noise Correlation Effect on Detection: Signals in Equicorrelated or Autoregressive(1) Gaussian.\\nYear: 2017\\n\\nAbstract: In this letter, we consider the effect of noise correlation on the error performance of binary hypothesis signal detection, when one of two deterministic signals is received in correlated Gaussian noise. For the likelihood ratio detection scheme, analytical performance results are derived for equicorrelated and autoregressive order one models. Although it is known previously that the best signal l...\",\n \"Title: An Optimized Algorithm for Calculating the Average Path Length of Complex Network\\nYear: 2017\\n\\nAbstract: To calculate the average path length of a large-scale complex network accurately and efficiently is always an important topic in the study of complex networks. For this purpose, an optimized algorithm is proposed based on reachability matrix as well as its efficiency analysis. The basic idea of this algorithm is to construct network distance matrix through network reachability matrix firstly, then to calculate the average path length according to distance matrix. It is proved and verified that the proposed algorithm is much more efficient than traditional algorithms like Floyd and Warshall algorithms for calculating large-scale complex networks with small-world effect.\",\n \"Title: Deep Reinforcement Learning With Sarsa And Q-Learning: A Hybrid Approach\\nYear: 2018\\n\\nAbstract: The commonly used Deep Q Networks is known to overestimate action values under certain conditions. It's also proved that overestimations do harm to performance, which might cause instability and divergence of learning. In this paper, we present the Deep Sarsa and Q Networks (DSQN) algorithm, which can considered as an enhancement to the Deep Q Networks algorithm. First, DSQN algorithm takes advantage of the experience replay and target network techniques in Deep Q Networks to improve the stability of neural networks. Second, double estimator is utilized for Q-learning to reduce overestimations. Especially, we introduce Sarsa learning to Deep Q Networks for removing overestimations further. Finally, DSQN algorithm is evaluated on cart-pole balancing, mountain car and lunarlander control task from the OpenAI Gym. The empirical evaluation results show that the proposed method leads to reduced overestimations, more stable learning process and improved performance.\",\n \"Title: Automatic Segmentation of Pathological Glomerular Basement Membrane in Transmission Electron Microscopy Images with Random Forest Stacks.\\nYear: 2019\\n\\nAbstract: Pathological classification through transmission electron microscopy (TEM) is essential for the diagnosis of certain nephropathy, and the changes of thickness in glomerular basement membrane (GBM) and presence of immune complex deposits in GBM are often used as diagnostic criteria. The automatic segmentation of the GBM on TEM images by computerized technology can provide clinicians with clear information about glomerular ultrastructural lesions. The GBM region on the TEM image is not only complicated and changeable in shape but also has a low contrast and wide distribution of grayscale. Consequently, extracting image features and obtaining excellent segmentation results are difficult. To address this problem, we introduce a random forest- (RF-) based machine learning method, namely, RF stacks (RFS), to realize automatic segmentation. Specifically, this work proposes a two-level integrated RFS that is more complicated than a one-level integrated RF to improve accuracy and generalization performance. The integrated strategies include training integration and testing integration. Training integration can derive a full-view RFS1 by simultaneously sampling several images of different grayscale ranges in the train phase. Testing integration can derive a zoom-view RFS2 by separately sampling the images of different grayscale ranges and integrating the results in the test phase. Experimental results illustrate that the proposed RFS can be used to automatically segment different morphologies and gray-level basement membranes. Future study on GBM thickness measurement and deposit identification will be based on this work.\",\n \"Title: Discrete-time sliding mode control for a class of nonlinear process\\nYear: 2020\\n\\nAbstract: The efficient control of nonlinear processes is generally considered to be challenging. The development of digital computers promotes the study of nonlinear process control technology. Due to the discrete sampling of digital computer, it is necessary to develop the corresponding control algorithms for nonlinear processes. In this paper, a new equivalent control-based discrete-time sliding mode control is proposed for a class of nonlinear process with uncertainty and external disturbance. An adaptive law and a disturbance observer are designed to estimate the uncertainty and the disturbance, respectively. By combining with them, the new discrete-time sliding mode control is developed with good performance. The corresponding theoretical analysis is well verified by using Lyapunov function. Finally, the proposed approach is demonstrated by case studies in light of MATLAB.\",\n \"Title: Learning to Learn: Hierarchical Meta-Critic Networks\\nYear: 2019\\n\\nAbstract: In recent years, deep reinforcement learning methods have achieved impressive performance in many different fields, including playing games, robotics, and dialogue systems. However, there are still a lot of restrictions here, one of which is the demand for massive amounts of sampled data. In this paper, a hierarchical meta-learning method based on the actor-critic algorithm is proposed for sample efficient learning. This method provides the transferable knowledge that can efficiently train an actor on a new task with a few trials. Specifically, a global basic critic, meta critic, and task specified network are shared within a distribution of tasks and are capable of criticizing any actor trying to solve any specified task. The hierarchical framework is applied to a critic network in the actor-critic algorithm for distilling meta-knowledge above the task level and addressing distinct tasks. The proposed method is evaluated on multiple classic control tasks with reinforcement learning algorithms, including the start-of-the-art meta-learning methods. The experimental results statistically demonstrate that the proposed method achieves state-of-the-art performance and attains better results with more depth of meta critic network.\",\n \"Title: Soft-Decision-Based Distributed Detection With Correlated Sensing Channels.\\nYear: 2019\\n\\nAbstract: Prior works on distributed detection with correlated Gaussian observations primarily dealt with single-bit reports to the fusion center and suboptimal fusion rules. Considering multiple bits and independent reporting channel errors, we formulate the optimal detection problem as a nonlinear integer programming problem for which the genetic algorithm is applied to find a suboptimal solution. The Bay...\",\n \"Title: Efficient discovery of sequence outlier patterns\\nYear: 2019\\n\\nAbstract: Modern Internet of Things (IoT) applications generate massive amounts of time-stamped data, much of it in the form of discrete, symbolic sequences. In this work, we present a new system called TOP that de<u>T</u>ects <u>O</u>utlier <u>P</u>atterns from these sequences. To solve the fundamental limitation of existing pattern mining semantics that miss outlier patterns hidden inside of larger frequent patterns, TOP offers new pattern semantics based on contextual patterns that distinguish the independent occurrence of a pattern from its occurrence as part of its super-pattern. We present efficient algorithms for the mining of this new class of contextual patterns. In particular, in contrast to the bottom-up strategy for state-of-the-art pattern mining techniques, our top-down Reduce strategy piggy backs pattern detection with the detection of the context in which a pattern occurs. Our approach achieves linear time complexity in the length of the input sequence. Effective optimization techniques such as context-driven search space pruning and inverted index-based outlier pattern detection are also proposed to further speed up contextual pattern mining. Our experimental evaluation demonstrates the effectiveness of TOP at capturing meaningful outlier patterns in several real-world IoT use cases. We also demonstrate the efficiency of TOP, showing it to be up to 2 orders of magnitude faster than adapting state-of-the-art mining to produce this new class of contextual outlier patterns, allowing us to scale outlier pattern mining to large sequence datasets.\",\n \"Title: A novel attention-guided convolutional network for the detection of abnormal cervical cells in cervical cancer screening\\nYear: 2021\\n\\nAbstract: •A novel attention-guided deep learning method to aid in cervical cancer screening.•Attention module to mimic the way pathologist reading a cervical cytology image in clinical workflow.•Preparing a dataset of around 70,552 cervical cytology images for abnormal cervical cell detection.•Comparing the performance of our method with the other related deep learning methods as well as human pathologists.•Results better than the other deep learning methods and comparable to human pathologists with 10-year experience.\",\n \"Title: Category-Aware Chronic Stress Detection on Microblogs\\nYear: 2022\\n\\nAbstract: People today live a stressful life. Compared with acute stress, long-term chronic stress is more harmful, and may cause or exacerbate many serious health problems, including high blood pressure, heart disease, chronic pain, and mental diseases. With social media becoming an integral part of our daily lives for information sharing and self-expression, detecting category-aware long-standing chronic stress from a large volume of historic open posts made by social media users is possible. In this study, we construct a data set containing 971 chronically stressed users with totally 54 546 open posts on Sina microblog from July 5, 2018 to December 1, 2019, and design two techniques for category-aware chronic stress detection: (1) a stress-oriented word embedding on the basis of an existing pre-trained word embedding, aiming to strengthen the sensibility of stress-related expressions for linguistic post analysis; (2) a multi-attention model with three layers (i.e., category-attention layer, posts self-attention layer, and category-specific post attention layer), aiming to capture inter-relevance from a sequence of posts and infer long-term stress categories and stress levels. The experimental results show that the proposed multi-attention model equipped with the stress-oriented word embedding can achieve 80.65% accuracy in detecting category-aware stress levels, 86.49% accuracy in detecting chronic stress levels only, and 93.07% accuracy in detecting chronic stress categories only. Limitations and implications of the study are also discussed at the end of the paper.\",\n \"Title: AI Meets Database: AI4DB and DB4AI\\nYear: 2021\\n\\nAbstract: ABSTRACTDatabase and Artificial Intelligence (AI) can benefit from each other. On one hand, AI can make database more intelligent (AI4DB). For example, traditional empirical database optimization techniques (e.g., cost estimation, join order selection, knob tuning, index and view advisor) cannot meet the high-performance requirement for large-scale database instances, various applications and diversified users, especially on the cloud. Fortunately, learning-based techniques can alleviate this problem. On the other hand, database techniques can optimize AI models (DB4AI). For example, AI is hard to deploy, because it requires developers to write complex codes and train complicated models. Database techniques can be used to reduce the complexity of using AI models, accelerate AI algorithms and provide AI capability inside databases. DB4AI and AI4DB have been extensively studied recently. In this tutorial, we review existing studies on AI4DB and DB4AI. For AI4DB, we review the techniques on learning-based database configuration, optimization, design, monitoring, and security. For DB4AI, we review AI-oriented declarative language, data governance, training acceleration, and inference acceleration. Finally, we provide research challenges and future directions in AI4DB and DB4AI.\",\n \"Title: ELITE: Robust Deep Anomaly Detection with Meta Gradient\\nYear: 2021\\n\\nAbstract: ABSTRACTDeep Learning techniques have been widely used in detecting anomalies from complex data. Most of these techniques are either unsupervised or semi-supervised because of a lack of a large number of labeled anomalies. However, they typically rely on a clean training data not polluted by anomalies to learn the distribution of the normal data. Otherwise, the learned distribution tends to be distorted and hence ineffective in distinguishing between normal and abnormal data. To solve this problem, we propose a novel approach called ELITE that uses a small number of labeled examples to infer the anomalies hidden in the training samples. It then turns these anomalies into useful signals that help to better detect anomalies from user data. Unlike the classical semi-supervised classification strategy which uses labeled examples as training data, ELITE uses them as validation set. It leverages the gradient of the validation loss to predict if one training sample is abnormal. The intuition is that correctly identifying the hidden anomalies could produce a better deep anomaly model with reduced validation loss. Our experiments on public benchmark datasets show that ELITE achieves up to 30% improvement in ROC AUC comparing to the state-of-the-art, yet robust to polluted training data.\",\n \"Title: Bionic Birdlike Imaging Using A Multi-Hyperuniform Led Array\\nYear: 2021\\n\\nAbstract: Digital cameras obtain color information of the scene using a chromatic filter, usually a Bayer filter, overlaid on a pixelated detector. However, the periodic arrangement of both the filter array and the detector array introduces frequency aliasing in sampling and color misregistration during demosaicking process which causes degradation of image quality. Inspired by the biological structure of the avian retinas, we developed a chromatic LED array which has a geometric arrangement of multi-hyperuniformity, which exhibits an irregularity on small-length scales but a quasi-uniformity on large scales, to suppress frequency aliasing and color misregistration in full color image retrieval. Experiments were performed with a single-pixel imaging system using the multi-hyperuniform chromatic LED array to provide structured illumination, and 208 fps frame rate was achieved at 32 x 32 pixel resolution. By comparing the experimental results with the images captured with a conventional digital camera, it has been demonstrated that the proposed imaging system forms images with less chromatic moire patterns and color misregistration artifacts. The concept proposed verified here could provide insights for the design and the manufacturing of future bionic imaging sensors.\",\n \"Title: LANCET: labeling complex data at scale\\nYear: 2021\\n\\nAbstract: AbstractCutting-edge machine learning techniques often require millions of labeled data objects to train a robust model. Because relying on humans to supply such a huge number of labels is rarely practical, automated methods for label generation are needed. Unfortunately, critical challenges in auto-labeling remain unsolved, including the following research questions: (1) which objects to ask humans to label, (2) how to automatically propagate labels to other objects, and (3) when to stop labeling. These three questions are not only each challenging in their own right, but they also correspond to tightly interdependent problems. Yet existing techniques provide at best isolated solutions to a subset of these challenges. In this work, we propose the first approach, called LANCET, that successfully addresses all three challenges in an integrated framework. LANCET is based on a theoretical foundation characterizing the properties that the labeled dataset must satisfy to train an effective prediction model, namely the Covariate-shift and the Continuity conditions. First, guided by the Covariate-shift condition, LANCET maps raw input data into a semantic feature space, where an unlabeled object is expected to share the same label with its near-by labeled neighbor. Next, guided by the Continuity condition, LANCET selects objects for labeling, aiming to ensure that unlabeled objects always have some sufficiently close labeled neighbors. These two strategies jointly maximize the accuracy of the automatically produced labels and the prediction accuracy of the machine learning models trained on these labels. Lastly, LANCET uses a distribution matching network to verify whether both the Covariate-shift and Continuity conditions hold, in which case it would be safe to terminate the labeling process. Our experiments on diverse public data sets demonstrate that LANCET consistently outperforms the state-of-the-art methods from Snuba to GOGGLES and other baselines by a large margin - up to 30 percentage points increase in accuracy.\",\n \"Title: ATLANTIC: making database differentially private and faster with accuracy guarantee\\nYear: 2021\\n\\nAbstract: AbstractDifferential privacy promises to enable data sharing and general data analytics while protecting individual privacy. Because the private data is often stored in the form of relational database that supports SQL queries, making SQL-based analytics differentially private is thus critical. However, the existing SQL-based differentially private systems either only focus on specific type of SQL queries such as COUNT or substantially modify the database engine, thus obstructing adoption in practice. Worse yet, these systems often do not guarantee the desired accuracy by the applications. In this demonstration, using the driving trace workload from Cambridge Mobile Telematics (CMT), we show that our ATLANTIC system, as a database middleware, enforces differential privacy for real-world SQL queries with provable accuracy guarantees and is compatible with existing databases. Moreover, using a sampling-based technique, ATLANTIC significantly speeds up the query execution, yet effectively amplifying the privacy guarantee.\",\n \"Title: Machine learning for databases\\nYear: 2021\\n\\nAbstract: AbstractMachine learning techniques have been proposed to optimize the databases. For example, traditional empirical database optimization techniques (e.g., cost estimation, join order selection, knob tuning, index and view advisor) cannot meet the high-performance requirement for large-scale database instances, various applications and diversified users, especially on the cloud. Fortunately, machine learning based techniques can alleviate this problem by judiciously selecting optimization strategy. In this tutorial, we categorize database tasks into three typical problems that can be optimized by different machine learning models, including NP-hard problems (e.g., knob space exploration, index/view selection, partition-key recommendation for offline optimization; query rewrite, join order selection for online optimization), regression problems (e.g., cost/cardinality estimation, index/view benefit estimation, query latency prediction), and prediction problems (e.g., query workload prediction). We review existing machine learning based techniques to address these problems and provide research challenges.\",\n \"Title: Pattern-Avoiding (0,1)-Matrices And Bases Of Permutation Matrices\\nYear: 2021\\n\\nAbstract: We investigate pattern-avoiding n x n (0, 1)-matrices with emphasis on patterns of length 3: pqr-avoiding where {p, q, r} subset of {1, 2,..., n}. We show that all such maximal (0, 1)-matrices contain the same number of 1's, and their structure is determined. We then show that the set of pqr-avoiding nxn permutation matrices span the linear space of dimension (n - 1)(2) + 1 generated by the n x n permutation matrices and determine a corresponding basis for each p, q, r. (c) 2021 Elsevier B.V. All rights reserved.\",\n \"Title: Combining Tracking and Remote Sensing to Identify Critical Year-Round Site, Habitat Use and Migratory Connectivity of a Threatened Waterbird Species\\nYear: 2021\\n\\nAbstract: We tracked 39 western flyway white-naped cranes (Antigone vipio) throughout multiple annual cycles from June 2017 to July 2020, using GSM-GPS loggers providing positions every 10-min to describe migration routes and key staging areas used between their Mongolian breeding and wintering areas in China's Yangtze River Basin. The results demonstrated that white-naped cranes migrated an average of 2556 km (& PLUSMN;187.9 SD) in autumn and 2673 km (& PLUSMN;342.3) in spring. We identified 86 critical stopover sites that supported individuals for more than 14 days, within a 100-800 km wide migratory corridor. This study also confirmed that Luan River catchment is the most important staging region, where white-naped cranes spent 18% of the annual cycle (in both spring and autumn) each year. Throughout the annual cycle, 69% of the tracking locations were from outside of the currently protected areas, while none of the critical staging areas enjoyed any form of site protection. We see further future potential to combine avian tracking data and remote-sensing information throughout the annual range of the white-naped crane to restore it and other such species to a more favourable conservation status.</p>\",\n \"Title: Distributed Top-N Local Outlier Detection In Big Data\\nYear: 2017\\n\\nAbstract: The concept of Top-N local outlier that focuses on the detection of the N points with the largest Local Outlier Factor (LOF) score has been shown to be very effective for identifying outliers in big datasets. However, detecting Top-N local outliers is computationally expensive, since the computation of LOF scores for all data points requires a huge number of high complexity k-nearest neighbor (kNN) searches. In this work, we thus present the first distributed solution to tackle this problem of Top-N local outlier detection (DTOLF). First, DTOLF features an innovative safe elimination strategy that efficiently identifies dually-safe points, namely those that are guaranteed to (1) not be classified as Top-N outliers and (2) not be needed as neighbors of points residing on other machines. Therefore, it effectively minimizes both the processing and communication costs of the Top-N outlier detection process. Further, based on the well-accepted observation that strong correlations among attributes are prevalent in real world datasets, we propose correlation-aware optimization strategies that ensure the effectiveness of grid-based partitioning and of the safe elimination strategy in multi-dimensional datasets. Our extensive experimental evaluation on OpenStreetMap, SDSS, and TIGER datasets demonstrates the effectiveness of DTOLF - up to 10 times faster than the alternative methods and scaling to terabyte level datasets.\",\n \"Title: A multipopulation evolutionary framework with Steffensen's method for dynamic multiobjective optimization problems\\nYear: 2021\\n\\nAbstract: Dynamic multiobjective optimization problems (DMOPs) require the evolutionary algorithms that can track the moving Pareto-optimal fronts efficiently. This paper presents a dynamic multiobjective evolutionary framework (DMOEF-MS), which adopts a novel multipopulation structure and Steffensen's method to solve DMOPs. In DMOEF-MS, only one population deals with the original DMOP, while the others focus on single-objective problems that are generated by the weighted summation of the original DMOP. Then, Steffensen's method is used to control the evolving process in two ways: prediction and diversity-maintenance. Particularly, the prediction strategy is devised to predict the next promising positions for the individuals that handle single-objective problems, and the diversity-maintenance strategy is used to increase population diversity before the environment changes and reinitialize the multiple populations after the environment changes. This paper gives a comprehensive comparison of DMOEF-MS with some state-of-the-art DMOEAs on 14 DMOPs and the experimental results demonstrate the effectiveness of the proposed algorithm.\",\n \"Title: Optimal Sensor Power Allocation for Decentralized Detection in Power Constrained Wireless Sensor Networks\\nYear: 2021\\n\\nAbstract: We consider a distributed detection network where several sensors amplify and forward their local observations over parallel access channels (PAC) to a fusion center (FC) in order to detect the presence or absence of a deterministic signal in Gaussian noise. Two observation models are studied: i) conditionally independent observations and ii) conditionally correlated observations obeying first-ord...\",\n \"Title: Detection Performance Comparison of Two-Sensor Parallel and Tandem Distributed Detection Networks\\nYear: 2021\\n\\nAbstract: For detecting deterministic signals corrupted by correlated Gaussian noise in a two-sensor distributed detection network, we study and compare the detection performance of the parallel topology with the tandem topology. It is known that under certain conditions, optimum sensor rules are in the form of single-threshold in both topologies. In other cases, by formulating the distributed detection pro...\",\n \"Title: Fair Coexistence of LAA and WiFi in Multi-Carrier LBT based on Joint Throughput and Airtime Fairness\\nYear: 2021\\n\\nAbstract: LAA-LBT is a sensing-based access mechanism for spectrum sharing which allows the harmonious coexistence of LTE with incumbents such as WiFi in the unlicensed band. The contention window size for random backoff for LBT procedure plays a significant role in determining the throughput, airtime and fair allocation of resources between stations contending on multiple channels. This paper focuses on fa...\",\n \"Title: Recurrent spiking neural network with dynamic presynaptic currents based on backpropagation\\nYear: 2022\\n\\nAbstract: In recent years, spiking neural networks (SNNs), which originated from the theoretical basis of neuroscience, have attracted neuromorphic computing and brain-like computing due to their advantages, such as neural dynamics and coding mechanism, which are similar to biological neurons. SNNs have become one of the mainstream frameworks in the field of brain-like computing. However, most of the Leaky Integrate-and-Fire (LIF) neuron models currently used by SNNs based on direct training of backpropagation (BP) do not consider the changes in the recurrent connections and the dynamic strength of neuron connections over time. This study presented the LIF neuron model with recurrent connections and a method for dynamically changing the presynaptic currents. Recurrent LIF neurons have an additional cyclic connection compared with classic LIF neurons. Their postsynaptic current stimulates a change in membrane potential at the next time point. Their dynamics were more similar to the activities of biological neurons. We also proposed an efficient and flexible BP training method for recurrent LIF neurons. On the basis of the above methods, we proposed the recurrent SNN with dynamic presynaptic currents based on backpropagation (RDS-BP). We test the proposed RDS-BP on three image data sets (MNIST, Fashion-MNIST and CIFAR-10) and two text data sets (IMDB and TREC). The results showed that the performance of RDS-BP not only exceeded the naive SNN models based on BP but also exceeded the SNN methods proposed in previous studies in recent years, which had excellent performance in previous experiments. Our work provides a new LIF neuron model with a recurrent connection and dynamic presynaptic current and a BP training arrangement for the proposed neuron, which could merit developments with neuromorphic and brain-like computing.\",\n \"Title: Scalable Motif Counting for Large-scale Temporal Graphs\\nYear: 2022\\n\\nAbstract: One fundamental problem in temporal graph analysis is to count the occurrences of small connected subgraph patterns (i.e., motifs), which benefits a broad range of real-world applications, such as anomaly detection, structure prediction, and network representation learning. However, existing works focused on exacting temporal motif are not scalable to large-scale temporal graph data, due to their heavy computational costs or inherent inadequacy of parallelism. In this work, we propose a scalable parallel framework for exactly counting temporal motifs in large-scale temporal graphs. We first categorize the temporal motifs based on their distinct properties, and then design customized algorithms that offer efficient strategies to exactly count the motif instances of each category. Moreover, our compact data structures, namely triple and quadruple counters, enable our algorithms to directly identify the temporal motif instances of each category, according to edge information and relationship between edges, therefore significantly improving the counting efficiency. Based on the proposed counting algorithms, we design a hierarchical parallel framework that featuring both inter- and intra-node parallel strategies, and fully leverages the multi-threading capacity of modern CPU to concurrently count all temporal motifs. Extensive experiments on sixteen real-world temporal graph datasets demonstrate the superiority and capability of our proposed framework for temporal motif counting, achieving up to 538x speedup compared to the stateof-the-art methods. The source code of our method is available at: https://github.com/steven- ccq/FAST- temporal-motif.\",\n \"Title: Green Synthesis of Phosphorescent Carbon Dots for Anticounterfeiting and Information Encryption\\nYear: 2022\\n\\nAbstract: Room-temperature phosphorescent (RTP) carbon dots (CDs) have promising applications in bioimaging, anticounterfeiting, and information encryption owing to their long lifetimes and wide Stokes shifts. Numerous researchers are interested in developing highly bright RTP CDs using environmentally friendly and safe synthesis processes (e.g., natural raw materials and zero-pollution production pathways). In this study, we successfully synthesized RTP CDs using a hydrothermal process employing natural vitamins as a raw material, ethylenediamine as a passivator, and boric acid as a phosphorescent enhancer, which is referred to as phosphorescent CD (PCD). The PCDs exhibit both bright blue fluorescence emission and green RTP emission, with a phosphorescence lifetime as long as 293 ms and an excellent green afterglow visible to the naked eye for up to 7.0 s. The total quantum yield is 12.69%. The phosphorescence quantum yield (PQY) is up to 5.15%. Based on the RTP performance, PCDs have been successfully employed for anticounterfeiting and information protection applications. The results of this study provide a green strategy for the scalable synthesis of RTP materials, which is a practical method for the fabrication of RTP materials with high efficiency and long afterglow lifetimes.\",\n \"Title: A Meta-learning based Stress Category Detection Framework on Social Media\\nYear: 2022\\n\\nAbstract: ABSTRACT Psychological stress has become a wider-spread and serious health issue in modern society. Detecting stressors that cause the stress could enable people to take effective actions to manage the stress. Previous work relied on the stressor dictionary built upon words from the stressor-related categories in the LIWC (Linguistic Inquiry and Word Count), and focused on stress categories that appear frequently on social media. In this paper, we build a meta-learning based stress category detection framework, which can learn how to distinguish a new stress category with very little data through learning on frequently appeared categories without relying on any lexicon. It is comprised of three modules, i.e., encoder module, induction module, and relation module. The encoder module focuses on learning category-relevant representation of each tweet with Dependency Graph Convolutional Network and tweet attention. The induction module deploys Mixture of Experts mechanism to integrate and summarize a representation for each category. The relation module is adopted to measure the correlation between each pair of query tweets and categories. Through the three modules and the meta-training process, we can then obtain a model which learns to learn how to identify stress categories and can directly be employed to a new category with little labelled data. Our experimental results show that the proposed framework can achieve 75.3 accuracy with 3 labeled data for the rarely appeared stress categories. We also build a stress category dataset consisting of 12 stress categories with 1,553 manually labeled stressful microblogs which can help train AI models to assist psychological stress diagnosis.\",\n \"Title: Fuzzy Grey Model for Forecasting Non-homogeneous Exponential Sequence\\nYear: 2022\\n\\nAbstract: Getting accurate results when GM (1, 1) model is used for fitting and predicting approximate non-homogeneous exponential sequence, is a challenge. We sought to address this issue by combining Grey Theory and Credibility Theory, to develop a fuzzy GM (1, 1) model (FGM), which introduces the double exponential fuzzy numbers and its membership function. The expectation of fuzzy variables for replacing the non-homogeneous exponential sequence was calculated by Credibility Theory, i.e. the homogeneous process. The novel method yields unbiased results when used in fitting and predicting the tight non-homogeneous exponential sequence. Finally, we use an empirical case and a numerical sequence case to illustrate the effectiveness, feasibility, and optimization of the FGM (1, 1) model.\",\n \"Title: A Friend-or-Foe framework for multi-agent reinforcement learning policy generation in mixing cooperative-competitive scenarios\\nYear: 2022\\n\\nAbstract: Although multi-agent deep deterministic policy gradient is a classic deep reinforcement learning algorithm in multi-agent systems. It also has critical problems such as poor training stability and low policy robustness, which significantly limit the capability and application of the algorithm. So this article proposes an improved algorithm called friend-or-foe multi-agent deep deterministic policy gradient for solving the above problems. The main innovations are as follows: (1) inspired by the concept of friend-or-foe game theory, we modified the framework of the original multi-agent deep deterministic policy gradient by using two identical training networks with agents' optimal and worst actions input, which improves the robustness of training policies, and (2) we propose an action perturbation technique based on gradient-descent to expand the selection range of actions, thereby improving training stability of our proposing algorithm. Finally, we conducted multiple sets of comparative experiments between our friend-or-foe multi-agent deep deterministic policy gradient and original one in four authoritative mixed cooperative-competitive scenarios. The results show that our improving algorithm can simultaneously improve the training stability and the robustness of agents' generating policies in different complicated environments.\",\n \"Title: A direct construction of continuous leakage-resilient (H)IBE scheme with CCA security from dual system encryption\\nYear: 2023\\n\\nAbstract: Continuous leakage resilient semantically secure Identity-based Encryption (IBE) schemes created with dual system encryption technique were presented by Lewko et al. at TCC 2011 and Yuen et al. at Eurocrypt 2012, respectively. It has been a research challenge to achieve the security against chosen-ciphertext attacks (CCA). The previous attempts toward the CCA security rely on q-type assumptions, which are referred as non-static assumptions causing loose reduction in security proofs. In this paper, we provide a complete solution to the problem and show how to construct the continuous leakage-resilient IBE with weaker CCA security based on the dual system encryption technique, where the adversary is allowed to make continuous leakage queries. We are able to prove its security with static assumptions in the standard model. As a feature of our scheme, we allow leakage of multiple keys, i.e., leakage of the master secret key and the private key of user. Our scheme also enjoys better computational performance, since the round leakage parameter is independent of the plaintext space and has a constant size. Furthermore, our scheme can be easily extended to give the weaker CCA secure continuous leakage-resilient hierarchical identity-based encryption scheme with a short ciphertext length.\",\n \"Title: Fine-Grained Question-Level Deception Detection via Graph-Based Learning and Cross-Modal Fusion\\nYear: 2022\\n\\nAbstract: Automated deception detection has been found as a vital and concerned task, capable of assisting human users to assess truthfulness and detect deceptive behaviors in several situations (e.g., medical, legal, as well as occupational domains). As contact-free video cameras and data analysis techniques are leaping forward, leveraging one's visual, acoustic and textual information captured in a video can be cost-effective for deception detection. In this study, we aim at a fine-grained question-level deception detection task, focusing on detecting whether a subject lies or not in answering each question rather than providing an overall \\\"lie or not\\\" judgement. A Graph-based Cross-modal Fusion Model (GCFM) is presented to learn the inherent associations among the subject's reactions to different questions, plus a novel cross-modal attention mechanism to enhance the model's learning capability. As revealed by the experimental results on the two datasets, the proposed graph-based GCFM outperformed eight other methods, and its two alternatives (clustering K-means based and sequential learning LSTM based methods), achieving accuracy 88.14% and 86.91% on the two datasets, respectively. Besides, through association learning, GCFM could increase the accuracy by 1.87% and 4.33% on the two datasets, respectively. Furthermore, its cross-modal attention mechanism led to the improvement of accuracy by 2.44% and 2.95% on the two datasets, respectively.\",\n \"Title: Coupling a Physical Replica with a Digital Twin: A Comparison of Participatory Decision-Making Methods in an Urban Park Environment\\nYear: 2022\\n\\nAbstract: Public participation is crucial in promoting built environment quality. By using Nancuiping park in China as a case study, this research brings attention to the digital twin park compared to the physical replica in a participatory workshop. Using UAV oblique photography, we created a digital twin model of this park and divided it into six layers to better manage and analyze the environment. Bracing the 'bottom-up' design philosophy, in the workshop, we analyzed existing issues in the park and simulated built environment changes, taking suggestions and comments from participants into account to support the decision-making of the park's optimization. Our digital twin model and physical replica were assessed through a questionnaire in which 59 participants used 3 defined indicators: usability, interactivity, and scenario simulation and visualization quality. The results suggest that the physical replica is easier to use in the participatory design. However, the digital twin model can provide better interactivity and efficient scene simulation and visualization quality. The statistical analysis of the relationship between participants' feedback on the two models and their sociodemographics (age, gender, and education background) shows that age is a barrier to promoting digital twins for older participants. Meanwhile, the digital twin's highly interactive features and high-resolution visualization capability were attractive to the younger and well-educated participants. Our study indicates future directions to improve the urban digital twin by incorporating human feedback into the urban model, thus establishing a two-way interaction between the digital system, the physical environment, and human perceptions.\",\n \"Title: Average Operation Time of Bundle Protocol in Delay/Disruption-Tolerant Networks\\nYear: 2022\\n\\nAbstract: Performance analysis of the Bundle Protocol (BP) in Delay/ disruption-Tolerant Networks (DTN) has gained much interest. The analytic work of the average operation time (AOT) in BP, for different channel conditions and system parameters, though critical to understanding performance and designing system, is still incomplete. Existing results, such as the average file delivery time (AFDT), provide reasonably close estimates in some cases but exhibit large discrepancies in other cases. In this paper, we provide a holistic probabilistic analysis of the BP process, particularly in the number of error bundles and the position of the last error bundle in each and the last rounds of transmission. We provide, for the first time, an exact solution for the AOT of the BP process. The derivation works for both symmetric and asymmetric channels and is in general for any given maximum number of transmissions rounds. When the unlimited number of transmission rounds is considered, AOT becomes AFDT. The results are further utilized to select the optimal bundle size that gives the minimum file delivery time. Validation via simulations and comparison with existing work are also provided.\",\n \"Title: Performance of XOR Rule for Decentralized Detection of Deterministic Signals in Bivariate Gaussian Noise\\nYear: 2022\\n\\nAbstract: In this paper, we consider the performance of exclusive-OR (XOR) rule in detecting the presence or absence of a deterministic signal in bivariate Gaussian noise. Signals, when present at the two sensors, are assumed unequal, whereas the noise components have identical marginal distribution but are correlated. The sensors send their one-bit quantized data to a fusion center, which then employs the XOR rule to arrive at the final decision. Here we prove that, in the limit as the correlation coefficient r approaches 1, the optimum fusion rule for both parallel and tandem topologies is XOR with identical, alternating partitions (XORAP) of the observations at the sensors. We further quantify the asymptotic decrease of the Bayes error of XORAP towards zero as a constant multiplied by root 1- r, as r approaches 1. When compared to the asymptotic Bayes error of CLRT, which decreases to zero exponentially fast, as a function of 1/(1-r), the Bayes error of XORAP decreases to zero much slower.\",\n \"Title: A Method of the Coverage Ratio of Street Trees Based on Deep Learning\\nYear: 2022\\n\\nAbstract: The street trees coverage ratio provides reliable data support for urban ecological environment assessment, which plays an important part in the ecological environment index calculation. Aiming at the statistical estimation of urban street trees coverage ratio, an integrated model based on YOLOv4 and Unet network for detecting and extracting street trees from remote sensing images is proposed, and obtain the estimated street trees coverage ratio in images accurately. The experiments are carried out under self-made dataset, and the results show that the accuracy of street trees detection is 94.91%, and the street trees coverage ratio is 16.30% and 13.81% in the two experimental urban scenes. The MIoU of contour extraction is 98.25%, and the estimated coverage accuracy is improved by 6.89% and 5.79%, respectively. The result indicates that the proposed model achieves the automation of contour extraction of street trees and more accurate estimation of street trees coverage ratio.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":189,"string":"189"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13379,"string":"13,379"}}},{"rowIdx":13380,"cells":{"question_id":{"kind":"string","value":"Luca Cardelli"},"question":{"kind":"string","value":"Generate an abstract for the title \"BioAmbients: an abstraction for biological compartments\" using the following items: Biomolecular systems, compartments, π-calculus process algebra, BioAmbients calculus, molecular localization."},"answer":{"kind":"string","value":"Biomolecular systems, composed of networks of proteins, underlie the major functions of living cells. Compartments are key to the organization of such systems. We have previously developed an abstraction for biomolecular systems using the π-calculus process algebra, which successfully handled their molecular and biochemical aspects, but provided only a limited solution for representing compartments. In this work, we extend this abstraction to handle compartments. We are motivated by the ambient calculus, a process algebra for the specification of process location and movement through computational domains. We present the BioAmbients calculus, which is suitable for representing various aspects of molecular localization and compartmentalization, including the movement of molecules between compartments, the dynamic rearrangement of cellular compartments, and the interaction between molecules in a compartmentalized setting. Guided by the calculus, we adapt the BioSpi simulation system, to provide an extended modular framework for molecular and cellular compartmentalization, and we use it to model and study a complex multi-cellular system."},"correct_answer":{"kind":"string","value":"Biomolecular systems, composed of networks of proteins, underlie the major functions of living cells. Compartments are key to the organization of such systems. We have previously developed an abstraction for biomolecular systems using the π-calculus process algebra, which successfully handled their molecular and biochemical aspects, but provided only a limited solution for representing compartments. In this work, we extend this abstraction to handle compartments. We are motivated by the ambient calculus, a process algebra for the specification of process location and movement through computational domains. We present the BioAmbients calculus, which is suitable for representing various aspects of molecular localization and compartmentalization, including the movement of molecules between compartments, the dynamic rearrangement of cellular compartments, and the interaction between molecules in a compartmentalized setting. Guided by the calculus, we adapt the BioSpi simulation system, to provide an extended modular framework for molecular and cellular compartmentalization, and we use it to model and study a complex multi-cellular system."},"documents":{"kind":"list like","value":["Title: Global computation\nYear: 1997\n\nAbstract: Computation over planet-wide structures is hindered by administrative, architectural, and physical constraints. These problems are surmountable, but must be addressed by developing new models of programming and of computation.","Title: Explicit Substitutions\nYear: 1991\n\nAbstract: The ##-calculus is a re#nement of the #-calculus where substitutionsare manipulated explicitly. The ##-calculus provides a settingfor studying the theory of substitutions, with pleasant mathematicalproperties. It is also a useful bridge between the classical #-calculusand concrete implementations.#Digital Equipment Corporation, Systems Research Center.yEcole Normale Sup#erieure; part of this work was completed while at Digital EquipmentCorporation, Systems Research Center.z...","Title: Analog Processes\nYear: 1980\n\nAbstract: Without Abstract","Title: Artificial Biochemistry\nYear: 2009\n\nAbstract: We model chemical and biochemical systems as collectives of interacting stochastic automata, with each automaton representing\n a molecule that undergoes state transitions. In this artificial biochemistry, automata interact by the equivalent of the law of mass action. We investigate several simple but intriguing automata collectives\n by stochastic simulation and by ODE analysis.","Title: Migratory applications\nYear: 1996\n\nAbstract: We introduce a new genre of user interface applications that can migrate from one machine to another, taking their user interface and application contexts with them, and continue from where they left off. Such applications are not tied to one user or one machine, and can roam freely over the net- work, rendering service to a community of users, gathering human input and interacting with people. We envisage that this will support many new agent-based collaboration met- aphors. The ability to migrate executing programs has applicability to mobile computing as well. Users can have their applications travel with them, as they move from one computing environment to another. We present an elegant programming model for creating migratory applications and describe an implementation. The biggest strength of our implementation is that the details of migration are com- pletely hidden from the application programmer; arbitrary user interface applications can be migrated by a single \"migration\" command. We address system issues such as robustness, persistence and memory usage, and also human factors relating to the application design process, the inter - action metaphor and safety.","Title: Mobile Ambients\nYear: 1997\n\nAbstract: This chapter introduces a calculus describing the movement of processes and devices, including movement through administrative domains.","Title: Type systems\nYear: 1997\n\nAbstract: The fundamental purpose of a type system is to prevent the occurrence of execution er- rors during the running of a program. This informal statement motivates the study of type systems, but requires clarification. Its accuracy depends, first of all, on the rather subtle issue of what constitutes an execution error, which we will discuss in detail. Even when that is settled, the absence of execution errors is a nontrivial property. When such a property holds for all of the program runs that can be expressed within a programming language, we say that the language is type sound . It turns out that a fair amount of careful analysis is required to avoid false and embarrassing claims of type soundness for programming languages. As a consequence, the classification, descrip- tion, and study of type systems has emerged as a formal discipline. The formalization of type systems requires the development of precise notations and definitions, and the detailed proof of formal properties that give confidence in the appropriateness of the definitions. Sometimes the discipline becomes rather abstract. One should always remember, though, that the basic motivation is pragmatic: the ab- stractions have arisen out of necessity and can usually be related directly to concrete intuitions. Moreover, formal techniques need not be applied in full in order to be useful and influential. A knowledge of the main principles of type systems can help in avoid- ing obvious and not so obvious pitfalls, and can inspire regularity and orthogonality in language design. When properly developed, type systems provide conceptual tools with which to judge the adequacy of important aspects of language definitions. Informal language descriptions often fail to specify the type structure of a language in sufficient detail to allow unambiguous implementation. It often happens that different compilers for the same language implement slightly different type systems. Moreover, many language definitions have been found to be type unsound, allowing a program to crash even though it is judged acceptable by a typechecker . Ideally, formal type systems should be part of the definition of all typed programming languages. This way, typechecking algorithms could be measured unambiguously against precise specifications and, if at all possible and feasible, whole languages could be shown to be type sound. In this introductory section we present an informal nomenclature for typing, exe- cution errors, and related concepts. We discuss the expected properties and benefits of type systems, and we review how type systems can be formalized. The terminology used in the introduction is not completely standard; this is due to the inherent incon- sistency of standard terminology arising from various sources. In general, we avoid the","Title: Typeful Programming\nYear: 1989\n\nAbstract: There exists an identifiable programming style based on the widespread use of type information handled through mechanical typechecking techniques. This typeful programming style is in a sense independent of the language it is embedded in; it adapts equally well to functional, imperative, object-oriented, and algebraic programming, and it is not incompatible with relational and concurrent programming. The main purpose of this paper is to show how typeful programming is best supported by sophisticated type systems, and how these systems can help in clarifying programming issues and in adding power and regularity to languages. We start with an introduction to the notions of types, subtypes and polymorphism. Then we introduce a general framework, derived in part from constructive logic, into which most of the known type systems can be accommodated and extended. The main part of the paper shows how this framework can be adapted systematically to cope with actual programming constructs. For concreteness we describe a particular programming language with advanced features; the emphasis here is on the combination of subtyping and polymorphism. We then discuss how typing concepts apply to large programs, made of collections of modules, and very large programs, made of collections of large programs. We also sketch how typing applies to system programming; an area which by nature escapes rigid typing. In summary, we compare the most common programming styles, suggesting that many of them are compatible with, and benefit from, a typeful discipline.","Title: Reversible structures\nYear: 2011\n\nAbstract: Reversible structures are computational units that may progress forward and backward. We study weak coherent structures that are primarily inspired by DNA circuits and may be compiled in these systems and demonstrate a standardization theorem. When units have unique id, the standardization theorem may be strengthened in a form that bears a quadratic algorithm for reachability, a problem that is EXPSPACE-complete for generic structures. We then define a compilation of a concurrent calculus -- the asynchronous RCCS -- to DNA via reversible structures, thus yielding a finegrain implementation of memories of the past into chemistry.","Title: A Process Model of Actin Polymerisation\nYear: 2009\n\nAbstract: Actin is the monomeric subunit of actin filaments which form one of the three major cytoskeletal networks in eukaryotic cells. Actin dynamics, be it the polymerisation of actin monomers into filaments or the reverse process, plays a key role in many cellular activities such as cell motility and phagocytosis. There is a growing number of experimental, theoretical and mathematical studies on the components of actin polymerisation and depolymerisation. However, it remains a challenge to develop compositional models of actin dynamics, e.g., by using differential equations. In this paper, we propose compositional process algebra models of actin polymerisation, and present a geometric representation of these models that allows to generate movies reflecting their dynamics.","Title: Basic polymorphic typechecking\nYear: 1987\n\nAbstract: This paper islargely concerned with implicit polymorphism; it is nonetheless important to dedicate the rest ofthis section to the relationships between the two kinds of parametric polymorphism.","Title: Comparing object encodings\nYear: 1999\n\nAbstract: Recent years have seen the development of several foundational models for statically typed object-oriented programming. But despite their intuitive similarity, differences in the technical machinery used to formulate the various proposals have made them difficult to compare. Using the typed lambda-calculus F ω <: as a common basis, we now offer a detailed comparison of four models: (1) a recursive-record encoding similar to the ones used by Cardelli, Reddy, Cook, and others; (2) Hofmann, Pierce, and Turner's existential encoding; (3) Bruce's model based on existential and recursive types; and (4) Abadi, Cardelli, and Viswanathan's type-theoretic encoding of a calculus of primitive objects.","Title: Describing semistructured data\nYear: 2001\n\nAbstract: We introduce a rich language of descriptions for semistructured tree-like data, and we explain how such descriptions relate to the data they describe. Various query languages and data schemas can be based on such descriptions.","Title: Real Time Agents\nYear: 1982\n\nAbstract: Without Abstract","Title: Subtyping and parametricity\nYear: 1994\n\nAbstract: We study the interaction of subtyping and parametricity. We describe a logic for a programming language with parametric polymorphism and subtyping. The logic supports the formal definition and use of relational parametricity. We give two models for it, and compare it with other formal systems for the same language. In particular we examine the “Penn interpretation” of subtyping as implicit coercion. without subtyping, parametricity yields, for example, an encoding of abstract types and of initial algebras, with the corresponding proof principles of simulation and induction. With subtyping, we obtain partially abstract types and certain initial order-sorted algebras, and may derive proof principles for them","Title: Secrecy and Group Creation\nYear: 2000\n\nAbstract: We add an operation of group creation to the typed π-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. Intuitively, no channel belonging to a fresh group can be received by processes outside the initial scope of the group, even if those processes are untyped. We formalize this intuition by adapting a notion of secrecy introduced by Abadi, and proving a preservation of secrecy property.","Title: Subtyping recursive types\nYear: 1993\n\nAbstract: We investigate the interactions of subtyping and recursive types, in a simply typed &lgr;-calculus. The two fundamental questions here are whether two (recursive)types are in the subtype relation and whether a term has a type. To address the first question, we relate various definitions of type equivalence and subtyping that are induced by a model, an ordering on infinite trees, an algorithm, and a set of type rules. We show soundness and completeness among the rules, the algorithm, and the tree semantics. We also prove soundness and a restricted form of completeness for the model. To address the second question, we show that to every pair of types in the subtype relation we can associate a term whose denotation is the uniquely determined coercion map between the two types. Moreover, we derive an algorithm that, when given a term with implicit coercions, can infer its least type whenever possible.","Title: Processes in Space\nYear: 2010\n\nAbstract: We introduce a geometric process algebra based on affine geometry, with the aim of describing the concurrent evolution of\n geometric structures in 3D space. We prove a relativity theorem stating that algebraic equations are invariant under rigid\n body transformations.","Title: Processes in space\nYear: 2012\n\nAbstract: We introduce a geometric process algebra based on affine geometry, with the aim of describing the concurrent evolution of geometric structures in 3D space. We prove a relativity theorem stating that algebraic equations are invariant under rigid body transformations.","Title: Operations in Records\nYear: 1989\n\nAbstract: Abstract Wedefine,a simple ,collection of operations ,for creating and manipulating ,record structures, where records are intended as finite associations of values to labels. A second-order,type system ,over ,these ,operations ,supports ,both ,subtyping ,and polymorphism. We provide typechecking algorithms and limited semantic models. Our approach unifies and extends previous notions of records, bounded quantification, record extension, and parametrization by row-variables. The general aim isto provide foundations for concepts found in object-oriented languages, within a framework,based on typed lambda-calculus. Appears in: Mathematical Structures in Computer Science, vol 1, pp. 3-48, 1991 SRC Research Report 48, August 25, 1989. Revised January 1, 1993.","Title: On binary methods\nYear: 1995\n\nAbstract: Giving types to binary methods causes significant problems for object-oriented language designersand programmers. This paper offers a comprehensive description of the problems arising fromtyping binary methods, and collects and contrasts diverse views and solutions. It is intended toexpose a wide audience of readers to the current debate on this question.1 IntroductionBinary methods have caused great difficulty for designers of strongly typed object-oriented languagesand for programmers...","Title: Molecules as Automata\nYear: 2008\n\nAbstract: Molecular biology investigates the structure and function of biochemical systems starting from their basic building blocks: macromolecules. A macromolecule is a large, complex molecule (a protein or a nucleic acid) that usually has inner mutable state and external activity. Informal explanations of biochemical events trace individual macromolecules through their state changes and their interaction histories: a macromolecule is endowed with an identity that is retained through its transformations, even through changes in molecular energy and mass. A macromolecule, therefore, is qualitatively different from the small molecules of inorganic chemistry. Such molecules are stateless: in the standard notation for chemical reactions they are seemingly created and destroyed, and their atomic structure is used mainly for the bookkeeping required by the conservation of mass.","Title: Modular Markovian logic\nYear: 2011\n\nAbstract: We introduce Modular Markovian Logic (MML) for compositional continuous-time and continuous-space Markov processes. MML combines operators specific to stochastic logics with operators reflecting the modular structure of the models, similar to those used by spatial and separation logics. We present a complete Hilbert-style axiomatization for MML, prove the small model property and analyze the relation between stochastic bisimulation and logical equivalence.","Title: Wide-Area Languages\nYear: 1998\n\nAbstract: I discuss the implications of programmable wide-area networks on programming language features and design. Wide-area networks\n (WANs) provide a fundamentally different computational infrastructure than local-area networks (LANs). As with the switch\n from mainframes to LANs, the semantic difference of WANs will eventually be reflected in programming language features. The\n spread of LANs in the 70’s and 80’s produced client-server computing and distributed object-oriented programming. The spread\n of WANs demands new advances including, for example, mobile secure computing.","Title: Wide Area Computation\nYear: 1999\n\nAbstract: The last decades have seen the emergence of the sea of objects para- digm for structuring complex distributed systems on workstations and local area networks. In this approach, applications and system services are composed of and communicate among themselves through reliable and transparently accessible object interfaces, leading to the interaction of hundred or thousands of unstruc- tured objects. This approach has lead to major progress in software composability and re- liability. Unfortunately, it is based on a number of assumptions that do not hold on wide area networks. There, access to resources is intrinsically unreliable (be- cause of failure, congestion, voluntary disconnected operation, etc.) and not transparent (because of variations in latency and bandwidth, hardware and soft- ware mobility, and the presence of firewalls). These characteristics are so radical- ly different from the current computational norm that they amount to a new model of computation. We discuss the challenges of computation on wide area networks. Our ap- proach reflects the intuition that, to function satisfactorily on a wide area net- work, the sea of objects must be partitioned and made hierarchical, internally mobile, and secure. This paper is an abridged version of (3).","Title: A Query Language Based on the Ambient Logic\nYear: 2001\n\nAbstract: The ambient logic is a modal logic proposed to describe the structural and computational properties of distributed and mobile computation. The structural part of the ambient logic is, essentially, a logic of labeled trees, hence it turns out to be a good foundation for query languages for semistructured data, much in the same way as first order logic is a fitting foundation for relational query languages. We define here a query language for semistructured data that is based on the ambient logic, and we outline an execution model for this language. The language turns out to be quite expressive. Its strong foundations and the equivalences that hold in the ambient logic are helpful in the definition of the language semantics and execution model.","Title: Compiling a functional language\nYear: 1984\n\nAbstract: This paper summarizes my experience in implementing a compiler for a functional language. The language is ML(1) [Milner 84] and the compiler was first implemented in 1980 as a personal project when I was a postgraduate student at the University of Edinburgh(2). At the time, I was familiar with programming language semantics but knew very little about compiler technology; interpreters had been my main programming concern. Major influences in the design of this compiler have been [Steele 77] [Steele 78] and the implementation folklore for statically and dynamically scoped dialects of Lisp [Allen 78]. As a result, the internal structure of the compiler is fairly unorthodox, if compared for example with [Aho 78]. Anyway, a compiler for a language like ML has to be different. ML is interactive, statically scoped, strongly typed, polymorphic, and has first class higher-order functions, type inference and dynamic allocation. These features preclude many well-known implementation styles, particularly the ones used for Lisp (because of static scoping), the Algol family (because of functional values) and C (because of nested scoping and strong typing). The interaction of these features is what gives ML its “character”, and makes compilation challenging. The compiler has been recently partially converted to the new ML standard. The major points of interest which are discussed in this paper are: (a) the interactive interpreter-like usage; (b) the polymorphic type inference algorithm; (c) the compilation of pattern matching; (d) the optimization of the representation of user defined data types; (e) the compilation of functional closures, function application and variable access; (f) the intermediate abstract machine and its formal operational semantics; (g) modules and type-safe separate compilation.","Title: An Accidental Simula User\nYear: 2007\n\nAbstract: It was a simple choice, really, on an IBM 370 in the 70's, between APL, Fortran, Lisp 1.5, PL/1, COBOL, and Simula'67. Nothing could come close to Simula's combination of strong typing, garbage collection, and proper string processing. Separate compilation (prefix classes) and coroutines were nice bonuses. And then there were these ... \"objects\" but, well, nothing is perfect. Hot topics in those days were the freshly invented denotational semantics (which Simula didn't have), formal type systems (which objects didn't have), and abstract data types (which seemed to have confusingly little to do with classes). Still, Simula was the obvious choice to get something done comfortably because, after all, it was an improved Algol. It even had the functional programming feature of call-by-name by default. So, it became my first favorite language, for every reason other than it being object-oriented.The story I am going to tell is the very, very slow realization that Simula was the embodiment of a radically different philosophy of programming, and the gradual and difficult efforts to reconcile that philosophy with the formal methods that were being developed for procedural and functional programming. Along the way, domain theory helped rather unexpectedly, at least for a while. Type theory had to be recast for the task at hand. Landin's lambda-reductionism had to be partially abandoned. Always, there seemed to be a deep fundamental mismatch between objects and procedures, well described by Reynolds, that made any unification impossibly complicated. But in the end, both object-oriented and procedural programming have benefited from the clash of cultures. And the story is far from over yet, as witnessed by the still blooming area of program verification for both procedural and object-oriented languages.","Title: Abstractions for mobile computations\nYear: 1999\n\nAbstract: We discuss the difficulties caused by mobile computing and mobile computation over wide-area networks. We propose a unified framework for overcoming such difficulties.","Title: An imperative object calculus\nYear: 1995\n\nAbstract: We develop an imperative calculus of objects. Its main type con- structor is the one for object types, which incorporate variance annotations and Self types. A subtyping relation between object types supports object subsumption. The type system for objects relies on unusual but beneficial as- sumptions about the possible subtypes of an object type. With the addition of polymorphism, the calculus can express classes and inheritance.","Title: Greedy Regular Expression Matching\nYear: 2004\n\nAbstract: This paper studies the problem of matching sequences against regular expressions in order to produce structured values.","Title: On process rate semantics\nYear: 2008\n\nAbstract: We provide translations between process algebra and systems of chemical reactions. We show that the translations preserve discrete-state (stochastic) and continuous-state (concentration) semantics, and in particular that the continuous-state semantics of processes corresponds to the differential equations of chemistry based on the law of mass action. The novel semantics of processes so obtained equates processes that have the same state occupation dynamics, but which may have different interaction interfaces.","Title: On Subtyping and Matching\nYear: 1996\n\nAbstract: Abstract A relation between recursive object types, called matching , has been proposed as a generalization of subtyping matching does not support subsumption, but it does support inheritance of binary methods We argue that matching is a good idea, but that it should not be regarded as a form of F nally intended) We show that a new interpretation of matching as high er - order subtyping has better properties third - order construction, possibly the only one to have been proposed for general use in programming","Title: Persistence and type abstraction\nYear: 1985\n\nAbstract: types are a well known and effective way of structuring programs. The basic ide~ of information hiding can however conflict with the need to store data for long periods of time, ar make it accessible to different activities. In particular a typechecker must be able to recognize fl occurrence of the same abstract type during different activations, and must enforce the privacy, data representations. To achieve this, the persistent storage of data must preserve type information, and mu respect type abstraction. The use of type abstractions in the presence of persistent storage require that abstract types be made persistent as well. Under these conditions, we can preserve ty( security across distinct activations of the typechecker. The following is a brief account of how various models of abstraction and persisten¢ interacL We start by sketching a simple polymorphic language and its types and showing variot ways of modeling type abstraction in such a language. We then discuss some basic notior underlying persistent storage of typed objects, such as the intern and extem primitive and special type dynamic, and describe three persistence strategies. Finally we discuss the partieul~ problem of persistent abstract types.","Title: A theory of primitive objects: untyped and first-order systems\nYear: 1994\n\nAbstract: We introduce simple object calculi that support method override and object subsumption. We give an untyped calculus, typing rules, and equational rules. We illustrate the expressiveness of our calculi and the pitfalls that we avoid.","Title: On understanding types, data abstraction, and polymorphism\nYear: 1985\n\nAbstract: Our objective is to understand the notion of type in programming languages, present a model of typed, polymorphic programming languages that reflects recent research in type theory, and examine the relevance of recent research to the design of practical programming languages.Object-oriented languages provide both a framework and a motivation for exploring the interaction among the concepts of type, data abstraction, and polymorphism, since they extend the notion of type to data abstraction and since type inheritance is an important form of polymorphism. We develop a &lgr;-calculus-based model for type systems that allows us to explore these interactions in a simple setting, unencumbered by complexities of production programming languages.The evolution of languages from untyped universes to monomorphic and then polymorphic type systems is reviewed. Mechanisms for polymorphism such as overloading, coercion, subtyping, and parameterization are examined. A unifying framework for polymorphic type systems is developed in terms of the typed &lgr;-calculus augmented to include binding of types by quantification as well as binding of values by abstraction.The typed &lgr;-calculus is augmented by universal quantification to model generic functions with type parameters, existential quantification and packaging (information hiding) to model abstract data types, and bounded quantification to model subtypes and type inheritance. In this way we obtain a simple and precise characterization of a powerful type system that includes abstract data types, parametric polymorphism, and multiple inheritance in a single consistent framework. The mechanisms for type checking for the augmented &lgr;-calculus are discussed.The augmented typed &lgr;-calculus is used as a programming language for a variety of illustrative examples. We christen this language Fun because fun instead of &lgr; is the functional abstraction keyword and because it is pleasant to deal with.Fun is mathematically simple and can serve as a basis for the design and implementation of real programming languages with type facilities that are more powerful and expressive than those of existing programming languages. In particular, it provides a basis for the design of strongly typed object-oriented languages.","Title: Bitonal membrane systems: Interactions of biological membranes\nYear: 2008\n\nAbstract: Inspired by the alternating orientations of cellular membranes, we describe a structure of nested membranes that are colored in two alternating tones. We investigate a class of reactions that maintain the colored regions largely invariant at each step (bitonal reactions). These coloring constraints guide us towards a small and non-obvious set of basic reactions that are both realistic and complete. They are realistic because bitonality is related to an independent notion of locality, and because similar reactions are implemented by molecular machinery. They are complete because any bitonal reaction can be obtained from them. Such a set of reactions can then be used as the basis for descriptions of biological processes, and in particular for the description of transport networks in cellular biology.","Title: An Intuitive Automated Modelling Interface For Systems Biology\nYear: 2009\n\nAbstract: We introduce a natural language interface for building stochastic pi calculus models of biological systems. In this language, complex constructs describing biochemical events are built from basic primitives of association, dissociation and transformation. This language thus allows us to model biochemical systems modularly by describing their dynamics in a narrative-style language, while making amendments, refinements and extensions on the models easy. We demonstrate the language on a model of Fc gamma receptor phosphorylation during phagocytosis. We provide a tool implementation of the translation into a stochastic pi calculus language, Microsoft Research's SPiM. (1 2)","Title: Strand algebras for DNA computing\nYear: 2011\n\nAbstract: We present a process algebra for DNA computing, discussing compilation of other formal systems into the algebra, and compilation of the algebra into DNA structures.","Title: A semantics of multiple inheritance\nYear: 1988\n\nAbstract: this paper is to present a clean semantics of multiple inheritance and to show that, in the context of strongly-typed, statically-scoped languages, a sound typechecking algorithm exists. Multiple inheritance is also interpreted in a broad sense: instead of being limited to objects, it is extended in a natural way to union types and to higher-order functional types. This constitutes a semantic basis for the unification of functional and object-oriented programming.","Title: Algebras and languages for molecular programming\nYear: 2010\n\nAbstract: Nucleic acids (DNA/RNA) encode information digitally, and are currently the only truly 'user-programmable' entities at the molecular scale. They can be used to manufacture nano-scale structures, to produce physical forces, to act as sensors and actuators, and to do computation in between. Eventually we will be able to interface them with biological machinery to detect and cure diseases at the cellular level under program control. The basic technology to create and manipulate these devices has existed for many years, but the imagination necessary to exploit them has been evolving slowly. Recently, some very simple computational schemes have been developed that are autonomous (run on their own once started) and involve only short (easily synthesizable) DNA strands with no other complex molecules.","Title: Anytime, anywhere: modal logics for mobile ambients\nYear: 2000\n\nAbstract: The Ambient Calculus is a process calculus where processes may reside within a hierarchy of locations and modify it. The purpose of the calculus is to study mobility, which is seen as the change of spatial configurations over time. In order to describe properties of mobile computations we devise a modal logic that can talk about space as well as time, and that has the Ambient Calculus as a model.","Title: A peptide filtering relation quantifies MHC class I peptide optimization.\nYear: 2011\n\nAbstract: Major Histocompatibility Complex (MHC) class I molecules enable cytotoxic T lymphocytes to destroy virus-infected or cancerous cells, thereby preventing disease progression. MHC class I molecules provide a snapshot of the contents of a cell by binding to protein fragments arising from intracellular protein turnover and presenting these fragments at the cell surface. Competing fragments (peptides) are selected for cell-surface presentation on the basis of their ability to form a stable complex with MHC class I, by a process known as peptide optimization. A better understanding of the optimization process is important for our understanding of immunodominance, the predominance of some T lymphocyte specificities over others, which can determine the efficacy of an immune response, the danger of immune evasion, and the success of vaccination strategies. In this paper we present a dynamical systems model of peptide optimization by MHC class I. We incorporate the chaperone molecule tapasin, which has been shown to enhance peptide optimization to different extents for different MHC class I alleles. Using a combination of published and novel experimental data to parameterize the model, we arrive at a relation of peptide filtering, which quantifies peptide optimization as a function of peptide supply and peptide unbinding rates. From this relation, we find that tapasin enhances peptide unbinding to improve peptide optimization without significantly delaying the transit of MHC to the cell surface, and differences in peptide optimization across MHC class I alleles can be explained by allele-specific differences in peptide binding. Importantly, our filtering relation may be used to dynamically predict the cell surface abundance of any number of competing peptides by MHC class I alleles, providing a quantitative basis to investigate viral infection or disease at the cellular level. We exemplify this by simulating optimization of the distribution of peptides derived from Human Immunodeficiency Virus Gag-Pol polyprotein.","Title: Squeak: a language for communicating with mice\nYear: 1985\n\nAbstract: Graphical user interfaces are difficult to implement because of the essential concurrency among multiple interaction devices, such as mice, buttons, and keyboards. Squeak is a user interface implementation language that exploits this concurrency rather than hiding it, helping the programmer to express interactions using multiple devices. We present the motivation, design and semantics of squeak. The language is based on concurrent programming constructs but can be compiled into a conventional sequential language; our implementation generates C code. We discuss how squeak programs can be integrated into a graphics system written in a conventional language to implement large but regular user interfaces, and close with a description of the formal semantics.","Title: Computational modeling of the EGFR network elucidates control mechanisms regulating signal dynamics.\nYear: 2009\n\nAbstract: BACKGROUND: The epidermal growth factor receptor (EGFR) signaling pathway plays a key role in regulation of cellular growth and development. While highly studied, it is still not fully understood how the signal is orchestrated. One of the reasons for the complexity of this pathway is the extensive network of inter-connected components involved in the signaling. In the aim of identifying critical mechanisms controlling signal transduction we have performed extensive analysis of an executable model of the EGFR pathway using the stochastic pi-calculus as a modeling language. RESULTS: Our analysis, done through simulation of various perturbations, suggests that the EGFR pathway contains regions of functional redundancy in the upstream parts; in the event of low EGF stimulus or partial system failure, this redundancy helps to maintain functional robustness. Downstream parts, like the parts controlling Ras and ERK, have fewer redundancies, and more than 50% inhibition of specific reactions in those parts greatly attenuates signal response. In addition, we suggest an abstract model that captures the main control mechanisms in the pathway. Simulation of this abstract model suggests that without redundancies in the upstream modules, signal transduction through the entire pathway could be attenuated. In terms of specific control mechanisms, we have identified positive feedback loops whose role is to prolong the active state of key components (e.g., MEK-PP, Ras-GTP), and negative feedback loops that help promote signal adaptation and stabilization. CONCLUSIONS: The insights gained from simulating this executable model facilitate the formulation of specific hypotheses regarding the control mechanisms of the EGFR signaling, and further substantiate the benefit to construct abstract executable models of large complex biological networks.","Title: A spatial logic for concurrency (part I)\nYear: 2003\n\nAbstract: We present a logic that can express properties of freshness, secrecy, structure, and behavior of concurrent systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to composition, local name restriction, and a primitive fresh name quantifier. Properties can also be defined by recursion; a central aim of this paper is then the combination of a logical notion of freshness with inductive and coinductive definitions of properties.","Title: A Spatial Logic for Concurrency (Part II)\nYear: 2002\n\nAbstract: We present a modal logic for describing the spatial organization and the behavior of distributed systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to process composition and name hiding, and a fresh quantifier.","Title: Deciding validity in a spatial logic for trees\nYear: 2005\n\nAbstract: We consider a propositional spatial logic for finite trees. The logic includes $\\A \\Par \\B$ (tree composition), $\\A \\,{\\Guarantee}\\, \\B$ (the implication induced by composition), and $\\Zero$ (the unit of composition). We show that the satisfaction and validity problems are equivalent, and decidable. The crux of the argument is devising a finite enumeration of trees to consider when deciding whether a spatial implication is satisfied. We introduce a sequent calculus for the logic, and show it to be sound and complete with respect to an interpretation in terms of satisfaction. Finally, we describe a complete proof procedure for the sequent calculus. We envisage applications in the area of logic-based type systems for semistructured data. We describe a small programming language based on this idea.","Title: The Measurable Space of Stochastic Processes\nYear: 2014\n\nAbstract: We introduce a stochastic extension of CCS endowed with structural operational semantics expressed in terms of measure theory. The set of processes is organised as a measurable space by the sigma-algebra generated by structural congruence. The structural operational semantics associates to each process a set of measures over the space of processes. The measures encode the rates of the transitions from a process (state of a system) to a measurable set of processes. We prove that stochastic bisimulation is a congruence that extends structural congruence. In addition to an elegant operational semantics, our calculus provides a canonic way to define metrics on processes that measure that measure how similar two processes are in terms of behaviour.","Title: Equational properties of mobile ambients\nYear: 2003\n\nAbstract: The ambient calculus is a process calculus for describing mobile computation. We develop a theory of Morris-style contextual equivalence for proving properties of mobile ambients. We prove a context lemma that allows derivation of contextual equivalences by considering contexts of a particular limited form, rather than all arbitrary contexts. We give an activity lemma that characterises the possible interactions between a process and a context. We prove several examples of contextual equivalence. The proofs depend on characterising reductions in the ambient calculus in terms of a labelled transition system.","Title: Biological systems as reactive systems\nYear: 2005\n\nAbstract: Systems Biology is a new discipline aiming to understand the behavior of biological systems as it results from the (non-trivial, ”emergent”) interaction of biological components. We discuss some biological networks that are characterized by simple components, but by complex interactions. The components are separately described in stochastic pi-calculus, which is a ”programming language” that should scale up to description of large systems. The components are then wired together, and their interactions are studied by stochastic simulation. Subtle and unexpected behavior emerges even from simple circuits, and yet stable behavior emerges too, giving some hints about what may be critical and what may be irrelevant in the organization of biological networks.","Title: A process model of Rho GTP-binding proteins\nYear: 2009\n\nAbstract: Rho GTP-binding proteins play a key role as molecular switches in many cellular activities. In response to extracellular stimuli and with the help of regulators (GEF, GAP, Effector, GDI), these proteins serve as switches that interact with their environment in a complex manner. Based on the structure of a published ordinary differential equations (ODE) model, we first present a generic process model for the Rho GTP-binding proteins, and compare it with the ODE model. We then extend the basic model to include the behaviour of the GDI regulators and explore the parameter space for the extended model with respect to biological data from the literature. We discuss the challenges this extension brings and the directions of further research. In particular, we present techniques for modular representation and refinement of process models, where, for example, different Rho proteins with different rates for regulator interactions can be given as instances of the same parametric model.","Title: Ambient Groups and Mobility Types\nYear: 2000\n\nAbstract: We add name groups and group creation to the typed ambient calculus. Group creation is surprisingly interesting: it has the effect of statically preventing certain communications, and can thus block the accidental or malicious escape of capabilities that is a major concern in practical systems. Moreover, ambient groups allow us to refine our earlier work on type systems for ambient mobility. We present type systems in which groups identify the set of ambients that a process may cross or open.","Title: Abstract machines of systems biology\nYear: 2005\n\nAbstract: Living cells are extremely well-organized autonomous systems, consisting of discrete interacting components. Key to understanding and modeling their behavior is modeling their system organization. Four distinct chemical toolkits (classes of macromolecules) have been characterized, each combinatorial in nature. Each toolkit consists of a small number of simple components that are assembled (polymerized) into complex structures that interact in rich ways. Each toolkit abstracts away from chemistry; it embodies an abstract machine with its own instruction set and its own peculiar interaction model. These interaction models are highly effective, but are not ones commonly used in computing: proteins stick together, genes have fixed output, membranes carry activity on their surfaces. Biologists have invented a number of notations attempting to describe these abstract machines and the processes they implement. Moving up from molecular biology, systems biology aims to understand how these interaction models work, separately and together.","Title: A graphical representation for biological processes in the stochastic pi-calculus\nYear: 2006\n\nAbstract: This paper presents a graphical representation for the stochastic π-calculus, which is formalised by defining a corresponding graphical calculus. The graphical calculus is shown to be reduction equivalent to stochastic π, ensuring that the two calculi have the same expressive power. The graphical representation is used to model a couple of example biological systems, namely a bistable gene network and a mapk signalling cascade. One of the benefits of the representation is its ability to highlight the existence of cycles, which are a key feature of biological systems. Another benefit is its ability to animate interactions between system components, in order to visualise system dynamics. The graphical representation can also be used as a front end to a simulator for the stochastic π-calculus, to help make modelling and simulation of biological systems more accessible to non computer scientists.","Title: A language with distributed scope\nYear: 1995\n\nAbstract: Obliq is a lexically-scoped, untyped, interpreted language that supports distributed object-oriented computation. Obliq objects have state and are local to a site. Obliq computations can roam over the network, while maintaining network connections. Distributed lexical scoping is the key mechanism for managing distributed computation.","Title: A theory of primitive objects: second-order systems\nYear: 1995\n\nAbstract: We describe a second-order calculus of objects. The calculus supports object sub- sumption, method override, and the type Self. It is constructed as an extension of System F with subtyping, recursion, and first-order object types.","Title: A semantic basis for quest\nYear: 1990\n\nAbstract: Abstract Quest is a ,programming ,language ,based on impredicative, type ,quantifiers and subtyping within a three-level structure of kinds, types and type operators, and values. The semantics of Quest is rather challenging. In particular, difficulties arise when we try to model simultaneously features such as contravariantfunction spaces, record types, subtyping, recursive types, and fixpoints. Inthis paper we describe in detail the type inference rules for Quest, and we give them,meaning ,using a partial ,equivalence ,relation model ,of types. Subtyping is interpreted as in previous work by Bruce and Longo, but the interpretation of some aspects, namely subsumption, power kinds, and record subtyping, is novel. The latter is based on a new encoding of record types. Weconcentrate,on modeling ,quantifiers and subtyping; recursion is the subject of current work. Appears in: Journal of Functional Programming, Vol 1, Part 4, pp.417-458, Cambridge Univ. Press, Oct 1991. SRC Research Report 55, February 14, 1990. Revised January 1, 1993.","Title: A Spatial Logic for Concurrency\nYear: 2001\n\nAbstract: We present a logic that can express properties of freshness, secrecy, structure, and behavior of concurrent systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to composition, local name restriction, and a primitive freshname quantifier. Properties can also be defined by recursion; a central theme of this paper is then the combination of a logical notion of freshness with inductive and coinductive definitions of properties.","Title: Dynamic Typing in Polymorphic Languages\nYear: 1995\n\nAbstract: Types The interaction between the use of Dynamic and abstract data types gives rise to a puzzling design issue: should the type tag of a dynamically typed value containing an element of an abstract type be matched abstractly or concretely? There are good arguments for both choices: ffl Abstract matching protects the identity of "hidden " representation types and prevents accidental matches in cases where several abstract types happen to have the same representation. ffl Transparent matching...","Title: Extensible Grammars for Language Specialization\nYear: 1993\n\nAbstract: A frequent dilemma in the design of a database programming language is the choice between a language with a rich set of tailored notations for schema definitions, query expressions, etc., and a small, simple core language. We address this dilemma by proposing extensible grammars, a syntax-definition formalism for incremental language extensions and restrictions based on an initial core language. The translation of programs written in rich object languages into a small core language is defined via syntax-directed patterns. In contrast to macro-expansion and program-rewriting tools, our extensible grammars respect scoping rules. Therefore, we can introduce binding constructs while avoiding problems with unwanted name clashes. We develop extensible grammars and illustrate their use by extend- ing the lambda calculus with let-bindings, conditionals, and SQL-style query expressions. We then give a formal description of the underlying parsing, transformat,ion, and substitution rules. Finally, we sketch how these rules are exploit,ed in the implementation of a generic, extensible parser package.","Title: TQL: a query language for semistructured data based on the ambient logic\nYear: 2004\n\nAbstract: The ambient logic is a modal logic that was proposed for the description of the structural and computational properties of distributed and mobile computation. The structural part of the ambient logic is, essentially, a logic of labelled trees, hence it turns out to be a good foundation for query languages for semistructured data, much in the same way as first-order logic is a fitting foundation for relational query languages. We define here a query language for semistructured data that is based on the ambient logic, and we outline an execution model for this language. The language turns out to be quite expressive. Its strong foundations and the equivalences that hold in the ambient logic are helpful in the definition of the language semantics and execution model.","Title: Continuous Markovian Logics - Axiomatization and Quantified Metatheory\nYear: 2012\n\nAbstract: Continuous Markovian Logic (CML) is a multimodal logic that expresses quantitative and qualitative properties of continuous-time labelled Markov processes with arbitrary (analytic) state-spaces, henceforth called continuous Markov processes (CMPs). The modalities of CML evaluate the rates of the exponentially distributed random variables that characterize the duration of the labeled transitions of a CMP. In this paper we present weak and strong complete axiomatizations for CML and prove a series of metaproperties, including the finite model property and the construction of canonical models. CML characterizes stochastic bisimilarity and it supports the definition of a quantified extension of the satisfiability relation that measures the \"compatibility\" between a model and a property. In this context, the metaproperties allows us to prove two robustness theorems for the logic stating that one can perturb formulas and maintain \"approximate satisfaction\".","Title: Reversibility In Massive Concurrent Systems\nYear: 2011\n\nAbstract: We introduce reversible structures, an algebra for massive concurrent systems, where terms retain bits of causal dependencies that allow one to reverse computation histories. We then study the implementation of (weak coherent) reversible structures in three-domains DNA strands, which is the natural model that has inspired reversible structures. We finally provide schemas for modeling significant synchronization patterns of process algebra into reversible structures and discuss the encoding of asynchronous Reversible CCS.","Title: An Universality Result For A (Mem)Brane Calculus Based On Mate/Drip Operations\nYear: 2006\n\nAbstract: Operations with membranes are essential both in brane calculi and in membrane computing. In this paper we take four basic operations from brane calculi, pino, exo, mate, drip, we express them in terms of the membrane computing formalism, and then we investigate the computing power of the P systems using the mate, drip operations as unique evolution rules. All operations are controlled by - and make evolve - multisets of protein-objects embedded in the membranes themselves (not contained in the compartments of the cell, as standard in membrane computing; all compartments delimited by membranes are here empty). Somewhat surprisingly, for systems which use the mate, drip operations we obtain the Turing completeness. The power of P systems based on other operations remains to be investigated.","Title: Modern concurrency abstractions for C#\nYear: 2004\n\nAbstract: Polyphonic C♯ is an extension of the C♯ language with new asynchronous concurrency constructs, based on the join calculus. We describe the design and implementation of the language and give examples of its use in addressing a range of concurrent programming problems.","Title: Logical properties of name restriction\nYear: 2001\n\nAbstract: We extend the modal logic of ambients described in [7] to the full ambient calculus, including name restriction. We introduce logical operators that can be used to make assertions about restricted names, and we study their properties.","Title: From Processes to ODEs by Chemistry\nYear: 2008\n\nAbstract: We investigate the collective behavior of processes in terms of differential equations, using chemistry as a stepping stone. Chemical reactions can be converted to ordinary differential equations, and also to processes in a stochastic process algebra. Conversely, certain stochastic processes (in Chemical Parametric Form, or CPF) can be converted to chemical reactions. CPF is a subset of pi-calculus, but is already more powerful that what is strictly needed to represent chemistry: it supports also parameterization and compositional reuse of models. The mapping of CPF to chemistry thus induces a parametric and compositional mapping of CPF to differential equations; the indirect mapping through chemistry is easier to define and understand than a direct mapping. As an example, we derive a quantitative interleaving law from the differential equations.","Title: On the Computational Power of Biochemistry\nYear: 2008\n\nAbstract: We explore the computational power of biochemistry with respect to basic chemistry, identifying complexation as the basic mech- anism that distinguishes the former from the latter. We use two process algebras, the Chemical Ground Form (CGF) which is equivalent to basic chemistry, and the Biochemical Ground Form (BGF) which is a minimal- istic extension of CGF with primitives for complexation. We characterize an expressiveness gap: CGF is not Turing complete while BGF supports a nite precise encoding of Random Access Machines, a well-known Tur- ing powerful formalism.","Title: Mobility Types for Mobile Ambients\nYear: 1999\n\nAbstract: An ambient is a named cluster of processes and subambients, whichmoves as a group. The untyped ambient calculus is a process calculusin which ambients model a variety of concepts such as network nodes,packets, channels, and software agents. In these models, some ambientsare intended to be mobile, some immobile; and some are intendedto be ephemeral, some persistent. We describe type systems able toformalize these intentions: they can guarantee that an ambient willremain immobile, and that ...","Title: Manipulating Trees with Hidden Labels\nYear: 2003\n\nAbstract: We define an operational semantics and a type system for manipulating semistructured data that contains hidden information. The data model is simple la- beled trees with a hiding operator. Data manipulation is based on pattern matching, with types that track the use of hidden labels.","Title: Dynamic typing in a statically typed language\nYear: 1991\n\nAbstract: Statically typed programming languages allow earlier errorchecking, better enforcement of diciplined programming styles, and thegeneration of more efficient object code than languages where all typeconsistency checks are performed at run time. However, even instatically typed languages, there is often the need to deal with datawhose type cannot be determined at compile time. To handlesuch situations safely, we propose to add a typeDynamic whose values are pairs of a valuev and a type tagT where vhas the type denoted by T. Instances ofDynamic are built with an explicittagging construct and inspected with a type safetypecase construct.This paper explores the syntax, operational semantics, and denotational semantics of a simple language that includes the typeDynamic. We give examples of howdynamically typed values can be used in programming. Then we discuss anoperational semantics for our language and obtain a soundness theorem. Wepresent two formulations of the denotational semantics of this languageand relate them to the operational semantics. Finally, we consider theimplications of polymorphism and some implementation issues.","Title: A Process Model of Rho GTP-binding Proteins in the Context of Phagocytosis\nYear: 2008\n\nAbstract: At the early stages of the phagocytic signalling, Rho GTP-binding proteins play a key role. With the stimulus from the cell membrane and with the help from the regulators (GEF, GAP, Effector, GDI), these proteins serve as switches that interact with their environment in a complex manner. We present a generic process model for the Rho GTP-binding proteins, and compare it with a previous model that uses ordinary differential equations. We then extend the basic model to include the behaviour of the GDIs. We discuss the challenges this extension brings and directions of further research.","Title: Efficient, correct simulation of biological processes in the stochastic pi-calculus\nYear: 2007\n\nAbstract: This paper presents a simulation algorithm for the stochastic π-calculus, designed for the efficient simulation of biological systems with large numbers of molecules. The cost of a simulation depends on the number of species, rather than the number of molecules, resulting in a significant gain in efficiency. The algorithm is proved correct with respect to the calculus, and then used as a basis for implementing the latest version of the SPiM stochastic simulator. The algorithm is also suitable for generating graphical animations of simulations, in order to visualise system dynamics.","Title: Invited Talk: A Process Algebra Master Equation\nYear: 2007\n\nAbstract: A Master Equation provides a complete probabilis-tic description of the dynamics of stochastic processes. We give a master equation for a small stochastic process algebra (a subset of CCS with interaction rates). We show that it is equivalent to the standard Chemical Master Equation, connecting our process algebra to the stochastic chemistry of unary and bi-nary reactions.","Title: Transitions in programming models: 2\nYear: 2005\n\nAbstract: The future of programming languages is not what it used to be. From the 50's to the 90's, richer, more flexible, and more robust structures were imposed on raw computation. Generally, new models of data and control managed to subsume older ones. But now, as programs and applications expand beyond a single local network and a single administrative domain, the very nature of data and control changes, and many long-lasting conceptual invariants are disrupted. We discuss three of these disruptive changes, which seem to be happening all at the same time, and for related reasons: asynchronous concurrency, semistructured data, and (in much less detail) security abstractions. We outline research project that address issues in those areas, mostly as examples of much larger territories yet to explore.","Title: Termination Problems in Chemical Kinetics\nYear: 2008\n\nAbstract: We consider nondeterministic and probabilistic termination problems in a process algebra that is equivalent to basic chemistry. We show that the existence of a terminating computation is decidable, but that termination with any probability strictly greater than zero is undecidable. Moreover, we show that the fairness intrinsic in stochastic computations implies that termination of all computation paths is undecidable, while it is decidable in a nondeterministic framework.","Title: Two-Domain DNA Strand Displacement\nYear: 2013\n\nAbstract: We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions) in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal processing gates based on these structures, and show that these systems are amenable to formalisation and mechanical verification.","Title: Types for the ambient calculus\nYear: 2002\n\nAbstract: The ambient calculus is a concurrent calculus where the unifying notion of ambient is used to model many different constructs for distributed and mobile computation. We study a type system that describes several properties of ambient behavior. The type system allows ambients to be partitioned in disjoint sets (groups), according to the intended design of a system, in order to specify both the communication and the mobility behavior of ambients.","Title: A Compositional Approach to the Stochastic Dynamics of Gene Networks\nYear: 2005\n\nAbstract: We propose a compositional approach to the dynamics of gene regulatory networks based on the stochastic pi-calculus, and develop a representation of gene network elements which can be used to build complex circuits in a transparent and efficient way. To demonstrate the power of the approach we apply it to several artificial networks, such as the repressilator and combinatorial gene circuits first studied in Combinatorial Synthesis of Genetic Networks [1]. For two examples of the latter systems, we point out how the topology of the circuits and the interplay of the stochastic gate interactions influence the circuit behavior. Our approach may be useful for the testing of biological mechanisms proposed to explain the experimentally observed circuit dynamics.","Title: From X to Pi; Representing the Classical Sequent Calculus in the Pi-calculus\nYear: 2011\n\nAbstract: We study the Pi-calculus, enriched with pairing and non-blocking input, and define a notion of type assignment that uses the type constructor \"arrow\". We encode the circuits of the calculus X into this variant of Pi, and show that all reduction (cut-elimination) and assignable types are preserved. Since X enjoys the Curry-Howard isomorphism for Gentzen's calculus LK, this implies that all proofs in LK have a representation in Pi.","Title: An extension of system F with subtyping\nYear: 1991\n\nAbstract: System F is a well-known typed λ-calculus with polymorphic types, which provides a basis for polymorphic programming languages. We study an extension of F , called F <: (pronounced ef-sub ), that combines parametric polymorphism with subtyping. The main focus of the paper is the equational theory of F <: , which is related to PER models and the notion of parametricity. We study some categorical properties of the theory when restricted to closed terms, including interesting categorical isomorphisms. We also investigate proof-theoretical properties, such as the conservativity of typing judgments with respect to F . We demonstrate by a set of examples how a range of constructs may be encoded in F <: . These include record operations and subtyping hierarchies that are related to features of object-oriented languages.","Title: A Spatial Logic for Querying Graphs\nYear: 2002\n\nAbstract: We study a spatial logic for reasoning about labelled directed graphs, and the application of this logic to provide a query language for analysing and manipulating such graphs. We give a graph description using constructs from process algebra. We introduce a spatial logic in order to reason locally about disjoint subgraphs. We extend our logic to provide a query language which preserves the multiset semantics of our graph model. Our approach contrasts with the more traditional set-based semantics found in query languages such as TQL, Strudel and GraphLog.","Title: Turing universality of the biochemical ground form\nYear: 2010\n\nAbstract: We explore the expressive power of languages that naturally model biochemical interactions relative to languages that only naturally model basic chemical reactions, identifying molecular association as the basic mechanism that distinguishes the former from the latter. We use a process algebra, the Biochemical Ground Form (BGF), that adds primitives for molecular association to CGF, which is a process algebra that has been proved to be equivalent to the traditional notations for describing basic chemical reactions. We first observe that, unlike CGF, BGF is Turing universal as it supports a finite precise encoding of Random Access Machines, which comprise a well-known Turing powerful formalism. Then we prove that the Turing universality of BGF derives from the interplay between the molecular primitives of association and dissociation. In fact, the elimination from BGF of the primitives already present in CGF does not reduce the computational strength of the process algebra, but if either association or dissociation is removed, BGF ceases to be Turing complete.","Title: Service combinators for Web computing\nYear: 1999\n\nAbstract: The World Wide Web is rich in content and services, but access to these resources must be obtained mostly through manual browsers. We would like to be able to write programs that reproduce human browsing behavior, including reactions to slow transmission-rates and failures on many simultaneous links. We thus introduce a concurrent model that directly incorporates the notions of failure and rate of communication, and then describe programming constructs based on this model.","Title: Morphisms of reaction networks that couple structure to function.\nYear: 2014\n\nAbstract: The mechanisms underlying complex biological systems are routinely represented as networks. Network kinetics is widely studied, and so is the connection between network structure and behavior. However, similarity of mechanism is better revealed by relationships between network structures.We define morphisms (mappings) between reaction networks that establish structural connections between them. Some morphisms imply kinetic similarity, and yet their properties can be checked statically on the structure of the networks. In particular we can determine statically that a complex network will emulate a simpler network: it will reproduce its kinetics for all corresponding choices of reaction rates and initial conditions. We use this property to relate the kinetics of many common biological networks of different sizes, also relating them to a fundamental population algorithm.Structural similarity between reaction networks can be revealed by network morphisms, elucidating mechanistic and functional aspects of complex networks in terms of simpler networks.","Title: Lineage grammars: describing, simulating and analyzing population dynamics.\nYear: 2014\n\nAbstract: Precise description of the dynamics of biological processes would enable the mathematical analysis and computational simulation of complex biological phenomena. Languages such as Chemical Reaction Networks and Process Algebras cater for the detailed description of interactions among individuals and for the simulation and analysis of ensuing behaviors of populations. However, often knowledge of such interactions is lacking or not available. Yet complete oblivion to the environment would make the description of any biological process vacuous. Here we present a language for describing population dynamics that abstracts away detailed interaction among individuals, yet captures in broad terms the effect of the changing environment, based on environment-dependent Stochastic Tree Grammars (eSTG). It is comprised of a set of stochastic tree grammar transition rules, which are context-free and as such abstract away specific interactions among individuals. Transition rule probabilities and rates, however, can depend on global parameters such as population size, generation count, and elapsed time.We show that eSTGs conveniently describe population dynamics at multiple levels including cellular dynamics, tissue development and niches of organisms. Notably, we show the utilization of eSTG for cases in which the dynamics is regulated by environmental factors, which affect the fate and rate of decisions of the different species. eSTGs are lineage grammars, in the sense that execution of an eSTG program generates the corresponding lineage trees, which can be used to analyze the evolutionary and developmental history of the biological system under investigation. These lineage trees contain a representation of the entire events history of the system, including the dynamics that led to the existing as well as to the extinct individuals.We conclude that our suggested formalism can be used to easily specify, simulate and analyze complex biological systems, and supports modular description of local biological dynamics that can be later used as \"black boxes\" in a larger scope, thus enabling a gradual and hierarchical definition and simulation of complex biological systems. The simple, yet robust formalism enables to target a broad class of stochastic dynamic behaviors, especially those that can be modeled using global environmental feedback regulation rather than direct interaction between individuals.","Title: Phosphorelays Provide Tunable Signal Processing Capabilities for the Cell.\nYear: 2013\n\nAbstract: Achieving a complete understanding of cellular signal transduction requires deciphering the relation between structural and biochemical features of a signaling system and the shape of the signal-response relationship it embeds. Using explicit analytical expressions and numerical simulations, we present here this relation for four-layered phosphorelays, which are signaling systems that are ubiquitous in prokaryotes and also found in lower eukaryotes and plants. We derive an analytical expression that relates the shape of the signal-response relationship in a relay to the kinetic rates of forward, reverse phosphorylation and hydrolysis reactions. This reveals a set of mathematical conditions which, when satisfied, dictate the shape of the signal-response relationship. We find that a specific topology also observed in nature can satisfy these conditions in such a way to allow plasticity among hyperbolic and sigmoidal signal-response relationships. Particularly, the shape of the signal-response relationship of this relay topology can be tuned by altering kinetic rates and total protein levels at different parts of the relay. These findings provide an important step towards predicting response dynamics of phosphorelays, and the nature of subsequent physiological responses that they mediate, solely from topological features and few composite measurements; measuring the ratio of reverse and forward phosphorylation rate constants could be sufficient to determine the shape of the signal-response relationship the relay exhibits. Furthermore, they highlight the potential ways in which selective pressures on signal processing could have played a role in the evolution of the observed structural and biochemical characteristic in phosphorelays.","Title: A semantics of object types\nYear: 1994\n\nAbstract: We give a semantics for a typed object calculus, an extension of System F with object subsumption and method over- ride. We interpret the calculus in a per model, proving the soundness of both typing and equational rules. This semantics suggests a syntactic translation from our calculus into a simpler calculus with neither subtyping nor objects. 1. Objects, Records, and Functions Despite the many formal accounts of object-oriented languages, the meaning and the properties of object types remain unclear. In particular, the soundness of object subtyping depends on invariants difficult to capture with standard type constructions; attempts based on record types have been inspiring but not compelling. In order to study object types in a clear setting, we give semantics to an extension of Girard's System F (Girard, Lafont, Taylor 1989) with subtyping, recursion, and some basic object constructs. Like all common object-oriented languages, this calculus supports object subsumption and method override. With subsumption, a new object with more methods can replace an old object transparently. Override is the operation that modifies the behavior of an object, or class, by replacing one of its methods. Neither subsumption nor override is too hard to model in isolation, but their combination has been problematic (see Section 6). Our starting point is the naive view that an object is a record of methods, and that each method is a function. When a method of an object o is invoked, the corresponding function is applied to o. This view of objects as records of functions is often used informally in the literature and it underlies all implementations of standard (single-dispatch) object-oriented languages. In this work, we extend this view to object types. We construct a model based on partial equivalence relations (pers). In our interpretation, objects are records of functions, object types are certain unions of recursive record types, and subtypes are subsets. Along the way, we study unions of pers, and thereby obtain a per semantics for abstract data types and partially abstract data types. We prove the soundness of both typing and equational rules. The per interpretation is direct enough to be informative. In particular, it suggests a syntactic translation from our calculus to a less unconventional extension of System F, with recursion and records, but neither subtyping nor objects. The rest of this introduction describes objects, their intended behavior, and the semantic problems that our approach is designed to solve. Some of this material is borrowed from (Abadi, Cardelli 1994b; Abadi, Cardelli 1994c), where we develop typed and untyped object calculi. We start by describing an untyped calculus that includes object formation, method invocation, and method override. An object is a collection of components (l i=ai i Ï1..n), for distinct labels l i and associated methods a i. The order of these components does not matter. A method is a function having a special parameter, called self. A proper method makes use of its self parameter; a field is a method that ignores self. The letter Ϛ is used as a binder for self, like a special λ binder; Ϛ(x)b is a method with self parameter x and with body b. The object containing a given method is called the method's host object. A method invocation (or selection) is written o.l j, where lj is a label of o. It reduces to the result substituting o for the self parameter in the body of the method named l j. Thus, a method can be applied only to its host object; this invariant is essential for typing objects and for reasoning about them. A method override (or update) is written o.l jfiüϚ(y)b. The intent is to replace the method named l j of o with Ϛ(y)b. Our semantics of override is functional: the result of an override is a copy of the object where the overridden method has been replaced by the new one. This form of method override is more general than usual, in that it applies to objects rather than classes; the generality does not complicate our formal treatment and has advantages in simplicity and expressiveness. We give a direct, informal semantics of objects, viewing them as primitive: Primitive Semantics","Title: Gener: a minimal programming module for chemical controllers based on DNA strand displacement.\nYear: 2015\n\nAbstract: Gener is a development module for programming chemical controllers based on DNA strand displacement. Gener is developed with the aim of providing a simple interface that minimizes the opportunities for programming errors: Gener allows the user to test the computations of the DNA programs based on a simple two-domain strand displacement algebra, the minimal available so far. The tool allows the user to perform stepwise computations with respect to the rules of the algebra as well as exhaustive search of the computation space with different options for exploration and visualization. Gener can be used in combination with existing tools, and in particular, its programs can be exported to Microsoft Research's DSD tool as well as to LaTeX.","Title: Automated Design and Verification of Localized DNA Computation Circuits\nYear: 2015\n\nAbstract: Simple computations can be performed using the interactions between single-stranded molecules of DNA. These interactions are typically toehold-mediated strand displacement reactions in a well-mixed solution. We demonstrate that a DNA circuit with tethered reactants is a distributed system and show how it can be described as a stochastic Petri net. The system can be verified by mapping the Petri net onto a continuous time Markov chain, which can also be used to find an optimal design for the circuit. This theoretical machinery can be applied to create software that automatically designs a DNA circuit, linking an abstract propositional formula to a physical DNA computation system that is capable of evaluating it.","Title: Forward and Backward Bisimulations for Chemical Reaction Networks\nYear: 2015\n\nAbstract: We present two quantitative behavioral equivalences over species of a chemical reaction network (CRN) with semantics based on ordinary differential equations. Forward CRN bisimulation identifies a partition where each equivalence class represents the exact sum of the concentrations of the species belonging to that class. Backward CRN bisimulation relates species that have the identical solutions at all time points when starting from the same initial conditions. Both notions can be checked using only CRN syntactical information, i.e., by inspection of the set of reactions. We provide a unified algorithm that computes the coarsest refinement up to our bisimulations in polynomial time. Further, we give algorithms to compute quotient CRNs induced by a bisimulation. As an application, we find significant reductions in a number of models of biological processes from the literature. In two cases we allow the analysis of benchmark models which would be otherwise intractable due to their memory requirements.","Title: Stochastic Analysis of Chemical Reaction Networks Using Linear Noise Approximation\nYear: 2015\n\nAbstract: Stochastic evolution of Chemical Reactions Networks (CRNs) over time is usually analyzed through solving the Chemical Master Equation (CME) or performing extensive simulations. Analysing stochasticity is often needed, particularly when some molecules occur in low numbers. Unfortunately, both approaches become infeasible if the system is complex and/or it cannot be ensured that initial populations are small. We develop a probabilistic logic for CRNs that enables stochastic analysis of the evolution of populations of molecular species. We present an approximate model checking algorithm based on the Linear Noise Approximation (LNA) of the CME, whose computational complexity is independent of the population size of each species and polynomial in the number of different species. The algorithm requires the solution of first order polynomial differential equations. We prove that our approach is valid for any CRN close enough to the thermodynamical limit. However, we show on four case studies that it can still provide good approximation even for low molecule counts. Our approach enables rigorous analysis of CRNs that are not analyzable by solving the CME, but are far from the deterministic limit. Moreover, it can be used for a fast approximate stochastic characterization of a CRN.","Title: Symbolic computation of differential equivalences.\nYear: 2016\n\nAbstract: Ordinary differential equations (ODEs) are widespread in many natural sciences including chemistry, ecology, and systems biology, and in disciplines such as control theory and electrical engineering. Building on the celebrated molecules-as-processes paradigm, they have become increasingly popular in computer science, with high-level languages and formal methods such as Petri nets, process algebra, and rule-based systems that are interpreted as ODEs. We consider the problem of comparing and minimizing ODEs automatically. Influenced by traditional approaches in the theory of programming, we propose differential equivalence relations. We study them for a basic intermediate language, for which we have decidability results, that can be targeted by a class of high-level specifications. An ODE implicitly represents an uncountable state space, hence reasoning techniques cannot be borrowed from established domains such as probabilistic programs with finite-state Markov chain semantics. We provide novel symbolic procedures to check an equivalence and compute the largest one via partition refinement algorithms that use satisfiability modulo theories. We illustrate the generality of our framework by showing that differential equivalences include (i) well-known notions for the minimization of continuous-time Markov chains (lumpability), (ii)~bisimulations for chemical reaction networks recently proposed by Cardelli et al., and (iii) behavioral relations for process algebra with ODE semantics. With a prototype implementation we are able to detect equivalences in biochemical models from the literature that cannot be reduced using competing automatic techniques.","Title: Efficient Syntax-Driven Lumping of Differential Equations.\nYear: 2016\n\nAbstract: We present an algorithm to compute exact aggregations of a class of systems of ordinary differential equations ODEs. Our approach consists in an extension of Paige and Tarjan's seminal solution to the coarsest refinement problem by encoding an ODE system into a suitable discrete-state representation. In particular, we consider a simple extension of the syntax of elementary chemical reaction networks because i it can express ODEs with derivatives given by polynomials of degree at most two, which are relevant in many applications in natural sciences and engineering; and ii we can build on two recently introduced bisimulations, which yield two complementary notions of ODE lumping. Our algorithm computes the largest bisimulations in $$Or \\\\cdot s \\\\cdot \\\\log s$$ time, where r is the number of monomials and s is the number of variables in the ODEs. Numerical experiments on real-world models from biochemistry, electrical engineering, and structural mechanics show that our prototype is able to handle ODEs with millions of variables and monomials, providing significant model reductions.","Title: Chemical Reaction Network Designs for Asynchronous Logic Circuits.\nYear: 2018\n\nAbstract: Chemical reaction networks (CRNs) are a versatile language for describing the dynamical behaviour of chemical kinetics, capable of modelling a variety of digital and analogue processes. While CRN designs for synchronous sequential logic circuits have been proposed and their implementation in DNA demonstrated, a physical realisation of these devices is difficult because of their reliance on a clock. Asynchronous sequential logic, on the other hand, does not require a clock, and instead relies on handshaking protocols to ensure the temporal ordering of different phases of the computation. This paper provides novel CRN designs for the construction of asynchronous logic, arithmetic and control flow elements based on a bi-molecular reaction motif with catalytic reactions and uniform reaction rates. We model and validate the designs for the deterministic and stochastic semantics using Microsoft’s GEC tool and the probabilistic model checker PRISM, demonstrating their ability to emulate the function of asynchronous components under low molecular count.","Title: Approximation Of Probabilistic Reachability For Chemical Reaction Networks Using The Linear Noise Approximation\nYear: 2016\n\nAbstract: We study time-bounded probabilistic reachability for Chemical Reaction Networks (CRNs) using the Linear Noise Approximation (LNA). The LNA approximates the discrete stochastic semantics of a CRN in terms of a continuous space Gaussian process. We consider reachability regions expressed as intersections of finitely many linear inequalities over the species of a CRN. This restriction allows us to derive an abstraction of the original Gaussian process as a time-inhomogeneous discrete-time Markov chain (DTMC), such that the dimensionality of its state space is independent of the number of species of the CRN, ameliorating the state space explosion problem. We formulate an algorithm for approximate computation of time-bounded reachability probabilities on the resulting DTMC and show how to extend it to more complex temporal properties. We implement the algorithm and demonstrate on two case studies that it permits fast and scalable computation of reachability properties with controlled accuracy.","Title: Reachability Computation for Switching Diffusions: Finite Abstractions with Certifiable and Tuneable Precision.\nYear: 2017\n\nAbstract: We consider continuous time stochastic hybrid systems with no resets and continuous dynamics described by linear stochastic differential equations -- models also known as switching diffusions. We show that for this class of models reachability (and dually, safety) properties can be studied on an abstraction defined in terms of a discrete time and finite space Markov chain (DTMC), with provable error bounds. The technical contribution of the paper is a characterization of the uniform convergence of the time discretization of such stochastic processes with respect to safety properties. This allows us to newly provide a complete and sound numerical procedure for reachability and safety computation over switching diffusions.","Title: ERODE: A Tool for the Evaluation and Reduction of Ordinary Differential Equations.\nYear: 2017\n\nAbstract: We present ERODE, a multi-platform tool for the solution and exact reduction of systems of ordinary differential equations ODEs. ERODE supports two recently introduced, complementary, equivalence relations over ODE variables: forward differential equivalence yields a self-consistent aggregate system where each ODE gives the cumulative dynamics of the sum of the original variables in the respective equivalence class. Backward differential equivalence identifies variables that have identical solutions whenever starting from the same initial conditions. As back-end ERODE uses the well-known Z3 SMT solver to compute the largest equivalence that refines a given initial partition of ODE variables. In the special case of ODEs with polynomial derivatives of degree at most two covering affine systems and elementary chemical reaction networks, it implements a more efficient partition-refinement algorithm in the style of Paige and Tarjan. ERODE comes with a rich development environment based on the Eclipse plug-in framework offering: i seamless project management; ii a fully-featured text editor; and iii importing-exporting capabilities.","Title: Syntactic Markovian Bisimulation for Chemical Reaction Networks.\nYear: 2017\n\nAbstract: In chemical reaction networks (CRNs) with stochastic semantics based on continuous-time Markov chains (CTMCs), the typically large populations of species cause combinatorially large state spaces. This makes the analysis very difficult in practice and represents the major bottleneck for the applicability of minimization techniques based, for instance, on lumpability. In this paper we present syntactic Markovian bisimulation (SMB), a notion of bisimulation developed in the Larsen-Skou style of probabilistic bisimulation, defined over the structure of a CRN rather than over its underlying CTMC. SMB identifies a lumpable partition of the CTMC state space a priori, in the sense that it is an equivalence relation over species implying that two CTMC states are lumpable when they are invariant with respect to the total population of species within the same equivalence class. We develop an efficient partition-refinement algorithm which computes the largest SMB of a CRN in polynomial time in the number of species and reactions. We also provide an algorithm for obtaining a quotient network from an SMB that induces the lumped CTMC directly, thus avoiding the generation of the state space of the original CRN altogether. In practice, we show that SMB allows significant reductions in a number of models from the literature. Finally, we study SMB with respect to the deterministic semantics of CRNs based on ordinary differential equations (ODEs), where each equation gives the time-course evolution of the concentration of a species. SMB implies forward CRN bisimulation, a recently developed behavioral notion of equivalence for the ODE semantics, in an analogous sense: it yields a smaller ODE system that keeps track of the sums of the solutions for equivalent species.","Title: Maximal Aggregation Of Polynomial Dynamical Systems\nYear: 2017\n\nAbstract: Ordinary differential equations (ODEs) with polynomial derivatives are a fundamental tool for understanding the dynamics of systems across many branches of science, but our ability to gain mechanistic insight and effectively conduct numerical evaluations is critically hindered when dealing with large models. Here we propose an aggregation technique that rests on two notions of equivalence relating ODE variables whenever they have the same solution (backward criterion) or if a self-consistent system can be written for describing the evolution of sums of variables in the same equivalence class (forward criterion). A key feature of our proposal is to encode a polynomial ODE system into a finitary structure akin to a formal chemical reaction network. This enables the development of a discrete algorithm to efficiently compute the largest equivalence, building on approaches rooted in computer science to minimize basic models of computation through iterative partition refinements. The physical interpretability of the aggregation is shown on polynomial ODE systems for biochemical reaction networks, gene regulatory networks, and evolutionary game theory.","Title: Efficient Switches in Biology and Computer Science.\nYear: 2017\n\nAbstract: Biological systems are adapted to respond quickly to changes in their environment. Signal processing often leads to all-or-none switch-like activation of downstream pathways. Such biological switches are based on molecular interactions that form positive feedback loops. Proper signal processing and switching have to be made by the noisy interactions of fluctuating molecular components; still, switching has to happen quickly once a threshold in the input signal is reached. Several computing algorithms have been designed to perform similar all-or-none decisions with high efficiency. We discuss here how the structure and dynamical features of a computational algorithm resemble the behaviour of a large class of biological switches and what makes them work efficiently. Furthermore, we highlight what biologists can learn by looking at specific features of computational algorithms.","Title: Central Limit Model Checking.\nYear: 2018\n\nAbstract: We consider probabilistic model checking for continuous-time Markov chains (CTMCs) induced from Stochastic Reaction Networks against a fragment of Continuous Stochastic Logic (CSL) extended with reward operators. Classical numerical algorithms for CSL model checking based on uniformisation are limited to finite CTMCs and suffer from exponential growth of the state space with respect to the number of species. However, approximate techniques such as mean-field approximations and simulations combined with statistical inference are more scalable but can be time-consuming and do not support the full expressiveness of CSL. In this article, we employ a continuous-space approximation of the CTMC in terms of a Gaussian process based on the Central Limit Approximation, also known as the Linear Noise Approximation, whose solution requires solving a number of differential equations that is quadratic in the number of species and independent of the population size. We then develop efficient and scalable approximate model checking algorithms on the resulting Gaussian process, where we restrict the target regions for probabilistic reachability to convex polytopes. This allows us to derive an abstraction in terms of a time-inhomogeneous discrete-time Markov chain (DTMC), whose dimension is independent of the number of species, on which model checking is performed. Using results from probability theory, we prove the convergence in distribution of our algorithms to the corresponding measures on the original CTMC. We implement the techniques and, on a set of examples, demonstrate that they allow us to overcome the state space explosion problem, while still correctly characterizing the stochastic behaviour of the system. Our methods can be used for formal analysis of a wide range of distributed stochastic systems, including biochemical systems, sensor networks, and population protocols.","Title: Single molecules can operate as primitive biological sensors, switches and oscillators.\nYear: 2018\n\nAbstract: We propose that evolution could have converted this switch into a single molecule oscillator, which could have been used as a primitive timekeeper. We discuss how the structure of the simplest known circadian clock regulatory system, found in cyanobacteria, resembles the proposed single molecule oscillator. Besides, we speculate if such minimal systems could have existed in an RNA world.","Title: Robustness Guarantees for Bayesian Inference with Gaussian Processes\nYear: 2018\n\nAbstract: Bayesian inference and Gaussian processes are widely used in applications ranging from robotics and control to biological systems. Many of these applications are safety-critical and require a characterization of the uncertainty associated with the learning model and formal guarantees on its predictions. In this paper we define a robustness measure for Bayesian inference against input perturbations, given by the probability that, for a test point and a compact set in the input space containing the test point, the prediction of the learning model will remain delta - close for all the points in the set, for delta > 0. Such measures can be used to provide formal probabilistic guarantees for the absence of adversarial examples. By employing the theory of Gaussian processes, we derive upper bounds on the resulting robustness by utilising the Borell-TIS inequality, and propose algorithms for their computation. We evaluate our techniques on two examples, a GP regression problem and a fully-connected deep neural network, where we rely on weak convergence to GPs to study adversarial examples on the MNIST dataset.","Title: Computing with biological switches and clocks.\nYear: 2018\n\nAbstract: The complex dynamics of biological systems is primarily driven by molecular interactions that underpin the regulatory networks of cells. These networks typically contain positive and negative feedback loops, which are responsible for switch-like and oscillatory dynamics, respectively. Many computing systems rely on switches and clocks as computational modules. While the combination of such modules in biological systems leads to a variety of dynamical behaviours, it is also driving development of new computing algorithms. Here we present a historical perspective on computation by biological systems, with a focus on switches and clocks, and discuss parallels between biology and computing. We also outline our vision for the future of biological computing.","Title: Efficiency through Uncertainty: Scalable Formal Synthesis for Stochastic Hybrid Systems.\nYear: 2019\n\nAbstract: This work targets the development of an efficient abstraction method for formal analysis and control synthesis of discrete-time stochastic hybrid systems (SHS) with linear dynamics. The focus is on temporal logic specifications over both finite- and infinite-time horizons. The framework constructs a finite abstraction as a class of uncertain Markov models known as interval Markov decision process (IMDP). Then, a strategy that maximizes the satisfaction probability of the given specification is synthesized over the IMDP and mapped to the underlying SHS. In contrast to existing formal approaches, which are by and large limited to finite-time properties and rely on conservative over-approximations, we show that the exact abstraction error can be computed as a solution of convex optimization problems and can be embedded into the IMDP abstraction. This is later used in the synthesis step over both bounded- and unbounded-time properties, mitigating the known state-space explosion problem. Our experimental validation of the new approach compared to existing abstraction-based approaches shows: (i) significant (orders of magnitude) reduction of the abstraction error; (ii) marked speed-ups; and (iii) boosted scalability, allowing in particular to verify models with more than 10 continuous variables.","Title: Secrecy and group creation\nYear: 2005\n\nAbstract: We add an operation of group creation to the typed π-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. Intuitively, no channel belonging to a fresh group can be received by processes outside the initial scope of the group, even if those processes are untyped. We formalize this intuition by adapting a notion of secrecy introduced by Abadi, and proving a preservation of secrecy property.","Title: Programming Discrete Distributions with Chemical Reaction Networks.\nYear: 2016\n\nAbstract: We explore the range of probabilistic behaviours that can be engineered with Chemical Reaction Networks (CRNs). We give methods to “program” CRNs so that their steady state is chosen from some desired target distribution that has finite support in , with . Moreover, any distribution with countable infinite support can be approximated with arbitrarily small error under the norm. We also give optimized schemes for special distributions, including the uniform distribution. Finally, we formulate a calculus to compute on distributions that is complete for finite support distributions, and can be compiled to a restricted class of CRNs that at steady state realize those distributions.","Title: Comparing Chemical Reaction Networks: A Categorical and Algorithmic Perspective.\nYear: 2016\n\nAbstract: We study chemical reaction networks (CRNs) as a kernel language for concurrency models with semantics based on ordinary differential equations. We investigate the problem of comparing two CRNs, i.e., to decide whether the trajectories of a source CRN can be matched by a target CRN under an appropriate choice of initial conditions. Using a categorical framework, we extend and relate model-comparison approaches based on structural (syntactic) and on dynamical (semantic) properties of a CRN, proving their equivalence. Then, we provide an algorithm to compare CRNs, running linearly in time with respect to the cardinality of all possible comparisons. Finally, we apply our results to biological models from the literature.","Title: Statistical Guarantees for the Robustness of Bayesian Neural Networks.\nYear: 2019\n\nAbstract: We introduce a probabilistic robustness measure for Bayesian Neural Networks (BNNs), defined as the probability that, given a test point, there exists a point within a bounded set such that the BNN prediction differs between the two. Such a measure can be used, for instance, to quantify the probability of the existence of adversarial examples. Building on statistical verification techniques for probabilistic models, we develop a framework that allows us to estimate probabilistic robustness for a BNN with statistical guarantees, i.e., with a priori error and confidence bounds. We provide experimental comparison for several approximate BNN inference techniques on image classification tasks associated to MNIST and a two-class subset of the GTSRB dataset. Our results enable quantification of uncertainty of BNN predictions in adversarial settings.","Title: Robustness Quantification for Classification with Gaussian Processes.\nYear: 2019\n\nAbstract: We consider Bayesian classification with Gaussian processes (GPs) and define robustness of a classifier in terms of the worst-case difference in the classification probabilities with respect to input perturbations. For a subset of the input space $T\\subseteq \\mathbb{R}^m$ such properties reduce to computing the infimum and supremum of the classification probabilities for all points in $T$. Unfortunately, computing the above values is very challenging, as the classification probabilities cannot be expressed analytically. Nevertheless, using the theory of Gaussian processes, we develop a framework that, for a given dataset $\\mathcal{D}$, a compact set of input points $T\\subseteq \\mathbb{R}^m$ and an error threshold $\\epsilon>0$, computes lower and upper bounds of the classification probabilities by over-approximating the exact range with an error bounded by $\\epsilon$. We provide experimental comparison of several approximate inference methods for classification on tasks associated to MNIST and SPAM datasets showing that our results enable quantification of uncertainty in adversarial classification settings.","Title: Lumpability For Uncertain Continuous-Time Markov Chains\nYear: 2021\n\nAbstract: The assumption of perfect knowledge of rate parameters in continuous-time Markov chains (CTMCs) is undermined when confronted with reality, where they may be uncertain due to lack of information or because of measurement noise. In this paper we consider uncertain CTMCs, where rates are assumed to vary non-deterministically with time from bounded continuous intervals. This leads to a semantics which associates each state with the reachable set of its probability under all possible choices of the uncertain rates. We develop a notion of lumpability which identifies a partition of states where each block preserves the reachable set of the sum of its probabilities, essentially lifting the well-known CTMC ordinary lumpability to the uncertain setting. We proceed with this analogy with two further contributions: a logical characterization of uncertain CTMC lumping in terms of continuous stochastic logic; and a polynomial time and space algorithm for the minimization of uncertain CTMCs by partition refinement, using the CTMC lumping algorithm as an inner step. As a case study, we show that the minimizations in a substantial number of CTMC models reported in the literature are robust with respect to uncertainties around their original, fixed, rate values.","Title: A Language for Modeling and Optimizing Experimental Biological Protocols\nYear: 2021\n\nAbstract: Automation is becoming ubiquitous in all laboratory activities, moving towards precisely defined and codified laboratory protocols. However, the integration between laboratory protocols and mathematical models is still lacking. Models describe physical processes, while protocols define the steps carried out during an experiment: neither cover the domain of the other, although they both attempt to characterize the same phenomena. We should ideally start from an integrated description of both the model and the steps carried out to test it, to concurrently analyze uncertainties in model parameters, equipment tolerances, and data collection. To this end, we present a language to model and optimize experimental biochemical protocols that facilitates such an integrated description, and that can be combined with experimental data. We provide probabilistic semantics for our language in terms of Gaussian processes (GPs) based on the linear noise approximation (LNA) that formally characterizes the uncertainties in the data collection, the underlying model, and the protocol operations. In a set of case studies, we illustrate how the resulting framework allows for automated analysis and optimization of experimental protocols, including Gibson assembly protocols.</p>","Title: On the Design of a PID Bio-Controller With Set Point Weighting and Filtered Derivative Action\nYear: 2022\n\nAbstract: Effective and robust regulation of biomolecular processes is crucial for designing reliable synthetic bio-devices functioning in uncertain and constantly changing biological environments. Proportional-Integral-Derivative (PID) controllers are undeniably the most common way of implementing feedback control in modern technological applications. Here, we introduce a highly tunable PID bio-controller with set point weighting and filtered derivative action presented as a chemical reaction network with mass action kinetics. To demonstrate its effectiveness, we apply our PID scheme on a simple biological process of two mutually activated species, one of which is assumed to be the output of interest. To highlight its performance advantages we compare it to PI regulation using numerical simulations in both the deterministic and stochastic setting."],"string":"[\n \"Title: Global computation\\nYear: 1997\\n\\nAbstract: Computation over planet-wide structures is hindered by administrative, architectural, and physical constraints. These problems are surmountable, but must be addressed by developing new models of programming and of computation.\",\n \"Title: Explicit Substitutions\\nYear: 1991\\n\\nAbstract: The ##-calculus is a re#nement of the #-calculus where substitutionsare manipulated explicitly. The ##-calculus provides a settingfor studying the theory of substitutions, with pleasant mathematicalproperties. It is also a useful bridge between the classical #-calculusand concrete implementations.#Digital Equipment Corporation, Systems Research Center.yEcole Normale Sup#erieure; part of this work was completed while at Digital EquipmentCorporation, Systems Research Center.z...\",\n \"Title: Analog Processes\\nYear: 1980\\n\\nAbstract: Without Abstract\",\n \"Title: Artificial Biochemistry\\nYear: 2009\\n\\nAbstract: We model chemical and biochemical systems as collectives of interacting stochastic automata, with each automaton representing\\n a molecule that undergoes state transitions. In this artificial biochemistry, automata interact by the equivalent of the law of mass action. We investigate several simple but intriguing automata collectives\\n by stochastic simulation and by ODE analysis.\",\n \"Title: Migratory applications\\nYear: 1996\\n\\nAbstract: We introduce a new genre of user interface applications that can migrate from one machine to another, taking their user interface and application contexts with them, and continue from where they left off. Such applications are not tied to one user or one machine, and can roam freely over the net- work, rendering service to a community of users, gathering human input and interacting with people. We envisage that this will support many new agent-based collaboration met- aphors. The ability to migrate executing programs has applicability to mobile computing as well. Users can have their applications travel with them, as they move from one computing environment to another. We present an elegant programming model for creating migratory applications and describe an implementation. The biggest strength of our implementation is that the details of migration are com- pletely hidden from the application programmer; arbitrary user interface applications can be migrated by a single \\\"migration\\\" command. We address system issues such as robustness, persistence and memory usage, and also human factors relating to the application design process, the inter - action metaphor and safety.\",\n \"Title: Mobile Ambients\\nYear: 1997\\n\\nAbstract: This chapter introduces a calculus describing the movement of processes and devices, including movement through administrative domains.\",\n \"Title: Type systems\\nYear: 1997\\n\\nAbstract: The fundamental purpose of a type system is to prevent the occurrence of execution er- rors during the running of a program. This informal statement motivates the study of type systems, but requires clarification. Its accuracy depends, first of all, on the rather subtle issue of what constitutes an execution error, which we will discuss in detail. Even when that is settled, the absence of execution errors is a nontrivial property. When such a property holds for all of the program runs that can be expressed within a programming language, we say that the language is type sound . It turns out that a fair amount of careful analysis is required to avoid false and embarrassing claims of type soundness for programming languages. As a consequence, the classification, descrip- tion, and study of type systems has emerged as a formal discipline. The formalization of type systems requires the development of precise notations and definitions, and the detailed proof of formal properties that give confidence in the appropriateness of the definitions. Sometimes the discipline becomes rather abstract. One should always remember, though, that the basic motivation is pragmatic: the ab- stractions have arisen out of necessity and can usually be related directly to concrete intuitions. Moreover, formal techniques need not be applied in full in order to be useful and influential. A knowledge of the main principles of type systems can help in avoid- ing obvious and not so obvious pitfalls, and can inspire regularity and orthogonality in language design. When properly developed, type systems provide conceptual tools with which to judge the adequacy of important aspects of language definitions. Informal language descriptions often fail to specify the type structure of a language in sufficient detail to allow unambiguous implementation. It often happens that different compilers for the same language implement slightly different type systems. Moreover, many language definitions have been found to be type unsound, allowing a program to crash even though it is judged acceptable by a typechecker . Ideally, formal type systems should be part of the definition of all typed programming languages. This way, typechecking algorithms could be measured unambiguously against precise specifications and, if at all possible and feasible, whole languages could be shown to be type sound. In this introductory section we present an informal nomenclature for typing, exe- cution errors, and related concepts. We discuss the expected properties and benefits of type systems, and we review how type systems can be formalized. The terminology used in the introduction is not completely standard; this is due to the inherent incon- sistency of standard terminology arising from various sources. In general, we avoid the\",\n \"Title: Typeful Programming\\nYear: 1989\\n\\nAbstract: There exists an identifiable programming style based on the widespread use of type information handled through mechanical typechecking techniques. This typeful programming style is in a sense independent of the language it is embedded in; it adapts equally well to functional, imperative, object-oriented, and algebraic programming, and it is not incompatible with relational and concurrent programming. The main purpose of this paper is to show how typeful programming is best supported by sophisticated type systems, and how these systems can help in clarifying programming issues and in adding power and regularity to languages. We start with an introduction to the notions of types, subtypes and polymorphism. Then we introduce a general framework, derived in part from constructive logic, into which most of the known type systems can be accommodated and extended. The main part of the paper shows how this framework can be adapted systematically to cope with actual programming constructs. For concreteness we describe a particular programming language with advanced features; the emphasis here is on the combination of subtyping and polymorphism. We then discuss how typing concepts apply to large programs, made of collections of modules, and very large programs, made of collections of large programs. We also sketch how typing applies to system programming; an area which by nature escapes rigid typing. In summary, we compare the most common programming styles, suggesting that many of them are compatible with, and benefit from, a typeful discipline.\",\n \"Title: Reversible structures\\nYear: 2011\\n\\nAbstract: Reversible structures are computational units that may progress forward and backward. We study weak coherent structures that are primarily inspired by DNA circuits and may be compiled in these systems and demonstrate a standardization theorem. When units have unique id, the standardization theorem may be strengthened in a form that bears a quadratic algorithm for reachability, a problem that is EXPSPACE-complete for generic structures. We then define a compilation of a concurrent calculus -- the asynchronous RCCS -- to DNA via reversible structures, thus yielding a finegrain implementation of memories of the past into chemistry.\",\n \"Title: A Process Model of Actin Polymerisation\\nYear: 2009\\n\\nAbstract: Actin is the monomeric subunit of actin filaments which form one of the three major cytoskeletal networks in eukaryotic cells. Actin dynamics, be it the polymerisation of actin monomers into filaments or the reverse process, plays a key role in many cellular activities such as cell motility and phagocytosis. There is a growing number of experimental, theoretical and mathematical studies on the components of actin polymerisation and depolymerisation. However, it remains a challenge to develop compositional models of actin dynamics, e.g., by using differential equations. In this paper, we propose compositional process algebra models of actin polymerisation, and present a geometric representation of these models that allows to generate movies reflecting their dynamics.\",\n \"Title: Basic polymorphic typechecking\\nYear: 1987\\n\\nAbstract: This paper islargely concerned with implicit polymorphism; it is nonetheless important to dedicate the rest ofthis section to the relationships between the two kinds of parametric polymorphism.\",\n \"Title: Comparing object encodings\\nYear: 1999\\n\\nAbstract: Recent years have seen the development of several foundational models for statically typed object-oriented programming. But despite their intuitive similarity, differences in the technical machinery used to formulate the various proposals have made them difficult to compare. Using the typed lambda-calculus F ω <: as a common basis, we now offer a detailed comparison of four models: (1) a recursive-record encoding similar to the ones used by Cardelli, Reddy, Cook, and others; (2) Hofmann, Pierce, and Turner's existential encoding; (3) Bruce's model based on existential and recursive types; and (4) Abadi, Cardelli, and Viswanathan's type-theoretic encoding of a calculus of primitive objects.\",\n \"Title: Describing semistructured data\\nYear: 2001\\n\\nAbstract: We introduce a rich language of descriptions for semistructured tree-like data, and we explain how such descriptions relate to the data they describe. Various query languages and data schemas can be based on such descriptions.\",\n \"Title: Real Time Agents\\nYear: 1982\\n\\nAbstract: Without Abstract\",\n \"Title: Subtyping and parametricity\\nYear: 1994\\n\\nAbstract: We study the interaction of subtyping and parametricity. We describe a logic for a programming language with parametric polymorphism and subtyping. The logic supports the formal definition and use of relational parametricity. We give two models for it, and compare it with other formal systems for the same language. In particular we examine the “Penn interpretation” of subtyping as implicit coercion. without subtyping, parametricity yields, for example, an encoding of abstract types and of initial algebras, with the corresponding proof principles of simulation and induction. With subtyping, we obtain partially abstract types and certain initial order-sorted algebras, and may derive proof principles for them\",\n \"Title: Secrecy and Group Creation\\nYear: 2000\\n\\nAbstract: We add an operation of group creation to the typed π-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. Intuitively, no channel belonging to a fresh group can be received by processes outside the initial scope of the group, even if those processes are untyped. We formalize this intuition by adapting a notion of secrecy introduced by Abadi, and proving a preservation of secrecy property.\",\n \"Title: Subtyping recursive types\\nYear: 1993\\n\\nAbstract: We investigate the interactions of subtyping and recursive types, in a simply typed &lgr;-calculus. The two fundamental questions here are whether two (recursive)types are in the subtype relation and whether a term has a type. To address the first question, we relate various definitions of type equivalence and subtyping that are induced by a model, an ordering on infinite trees, an algorithm, and a set of type rules. We show soundness and completeness among the rules, the algorithm, and the tree semantics. We also prove soundness and a restricted form of completeness for the model. To address the second question, we show that to every pair of types in the subtype relation we can associate a term whose denotation is the uniquely determined coercion map between the two types. Moreover, we derive an algorithm that, when given a term with implicit coercions, can infer its least type whenever possible.\",\n \"Title: Processes in Space\\nYear: 2010\\n\\nAbstract: We introduce a geometric process algebra based on affine geometry, with the aim of describing the concurrent evolution of\\n geometric structures in 3D space. We prove a relativity theorem stating that algebraic equations are invariant under rigid\\n body transformations.\",\n \"Title: Processes in space\\nYear: 2012\\n\\nAbstract: We introduce a geometric process algebra based on affine geometry, with the aim of describing the concurrent evolution of geometric structures in 3D space. We prove a relativity theorem stating that algebraic equations are invariant under rigid body transformations.\",\n \"Title: Operations in Records\\nYear: 1989\\n\\nAbstract: Abstract Wedefine,a simple ,collection of operations ,for creating and manipulating ,record structures, where records are intended as finite associations of values to labels. A second-order,type system ,over ,these ,operations ,supports ,both ,subtyping ,and polymorphism. We provide typechecking algorithms and limited semantic models. Our approach unifies and extends previous notions of records, bounded quantification, record extension, and parametrization by row-variables. The general aim isto provide foundations for concepts found in object-oriented languages, within a framework,based on typed lambda-calculus. Appears in: Mathematical Structures in Computer Science, vol 1, pp. 3-48, 1991 SRC Research Report 48, August 25, 1989. Revised January 1, 1993.\",\n \"Title: On binary methods\\nYear: 1995\\n\\nAbstract: Giving types to binary methods causes significant problems for object-oriented language designersand programmers. This paper offers a comprehensive description of the problems arising fromtyping binary methods, and collects and contrasts diverse views and solutions. It is intended toexpose a wide audience of readers to the current debate on this question.1 IntroductionBinary methods have caused great difficulty for designers of strongly typed object-oriented languagesand for programmers...\",\n \"Title: Molecules as Automata\\nYear: 2008\\n\\nAbstract: Molecular biology investigates the structure and function of biochemical systems starting from their basic building blocks: macromolecules. A macromolecule is a large, complex molecule (a protein or a nucleic acid) that usually has inner mutable state and external activity. Informal explanations of biochemical events trace individual macromolecules through their state changes and their interaction histories: a macromolecule is endowed with an identity that is retained through its transformations, even through changes in molecular energy and mass. A macromolecule, therefore, is qualitatively different from the small molecules of inorganic chemistry. Such molecules are stateless: in the standard notation for chemical reactions they are seemingly created and destroyed, and their atomic structure is used mainly for the bookkeeping required by the conservation of mass.\",\n \"Title: Modular Markovian logic\\nYear: 2011\\n\\nAbstract: We introduce Modular Markovian Logic (MML) for compositional continuous-time and continuous-space Markov processes. MML combines operators specific to stochastic logics with operators reflecting the modular structure of the models, similar to those used by spatial and separation logics. We present a complete Hilbert-style axiomatization for MML, prove the small model property and analyze the relation between stochastic bisimulation and logical equivalence.\",\n \"Title: Wide-Area Languages\\nYear: 1998\\n\\nAbstract: I discuss the implications of programmable wide-area networks on programming language features and design. Wide-area networks\\n (WANs) provide a fundamentally different computational infrastructure than local-area networks (LANs). As with the switch\\n from mainframes to LANs, the semantic difference of WANs will eventually be reflected in programming language features. The\\n spread of LANs in the 70’s and 80’s produced client-server computing and distributed object-oriented programming. The spread\\n of WANs demands new advances including, for example, mobile secure computing.\",\n \"Title: Wide Area Computation\\nYear: 1999\\n\\nAbstract: The last decades have seen the emergence of the sea of objects para- digm for structuring complex distributed systems on workstations and local area networks. In this approach, applications and system services are composed of and communicate among themselves through reliable and transparently accessible object interfaces, leading to the interaction of hundred or thousands of unstruc- tured objects. This approach has lead to major progress in software composability and re- liability. Unfortunately, it is based on a number of assumptions that do not hold on wide area networks. There, access to resources is intrinsically unreliable (be- cause of failure, congestion, voluntary disconnected operation, etc.) and not transparent (because of variations in latency and bandwidth, hardware and soft- ware mobility, and the presence of firewalls). These characteristics are so radical- ly different from the current computational norm that they amount to a new model of computation. We discuss the challenges of computation on wide area networks. Our ap- proach reflects the intuition that, to function satisfactorily on a wide area net- work, the sea of objects must be partitioned and made hierarchical, internally mobile, and secure. This paper is an abridged version of (3).\",\n \"Title: A Query Language Based on the Ambient Logic\\nYear: 2001\\n\\nAbstract: The ambient logic is a modal logic proposed to describe the structural and computational properties of distributed and mobile computation. The structural part of the ambient logic is, essentially, a logic of labeled trees, hence it turns out to be a good foundation for query languages for semistructured data, much in the same way as first order logic is a fitting foundation for relational query languages. We define here a query language for semistructured data that is based on the ambient logic, and we outline an execution model for this language. The language turns out to be quite expressive. Its strong foundations and the equivalences that hold in the ambient logic are helpful in the definition of the language semantics and execution model.\",\n \"Title: Compiling a functional language\\nYear: 1984\\n\\nAbstract: This paper summarizes my experience in implementing a compiler for a functional language. The language is ML(1) [Milner 84] and the compiler was first implemented in 1980 as a personal project when I was a postgraduate student at the University of Edinburgh(2). At the time, I was familiar with programming language semantics but knew very little about compiler technology; interpreters had been my main programming concern. Major influences in the design of this compiler have been [Steele 77] [Steele 78] and the implementation folklore for statically and dynamically scoped dialects of Lisp [Allen 78]. As a result, the internal structure of the compiler is fairly unorthodox, if compared for example with [Aho 78]. Anyway, a compiler for a language like ML has to be different. ML is interactive, statically scoped, strongly typed, polymorphic, and has first class higher-order functions, type inference and dynamic allocation. These features preclude many well-known implementation styles, particularly the ones used for Lisp (because of static scoping), the Algol family (because of functional values) and C (because of nested scoping and strong typing). The interaction of these features is what gives ML its “character”, and makes compilation challenging. The compiler has been recently partially converted to the new ML standard. The major points of interest which are discussed in this paper are: (a) the interactive interpreter-like usage; (b) the polymorphic type inference algorithm; (c) the compilation of pattern matching; (d) the optimization of the representation of user defined data types; (e) the compilation of functional closures, function application and variable access; (f) the intermediate abstract machine and its formal operational semantics; (g) modules and type-safe separate compilation.\",\n \"Title: An Accidental Simula User\\nYear: 2007\\n\\nAbstract: It was a simple choice, really, on an IBM 370 in the 70's, between APL, Fortran, Lisp 1.5, PL/1, COBOL, and Simula'67. Nothing could come close to Simula's combination of strong typing, garbage collection, and proper string processing. Separate compilation (prefix classes) and coroutines were nice bonuses. And then there were these ... \\\"objects\\\" but, well, nothing is perfect. Hot topics in those days were the freshly invented denotational semantics (which Simula didn't have), formal type systems (which objects didn't have), and abstract data types (which seemed to have confusingly little to do with classes). Still, Simula was the obvious choice to get something done comfortably because, after all, it was an improved Algol. It even had the functional programming feature of call-by-name by default. So, it became my first favorite language, for every reason other than it being object-oriented.The story I am going to tell is the very, very slow realization that Simula was the embodiment of a radically different philosophy of programming, and the gradual and difficult efforts to reconcile that philosophy with the formal methods that were being developed for procedural and functional programming. Along the way, domain theory helped rather unexpectedly, at least for a while. Type theory had to be recast for the task at hand. Landin's lambda-reductionism had to be partially abandoned. Always, there seemed to be a deep fundamental mismatch between objects and procedures, well described by Reynolds, that made any unification impossibly complicated. But in the end, both object-oriented and procedural programming have benefited from the clash of cultures. And the story is far from over yet, as witnessed by the still blooming area of program verification for both procedural and object-oriented languages.\",\n \"Title: Abstractions for mobile computations\\nYear: 1999\\n\\nAbstract: We discuss the difficulties caused by mobile computing and mobile computation over wide-area networks. We propose a unified framework for overcoming such difficulties.\",\n \"Title: An imperative object calculus\\nYear: 1995\\n\\nAbstract: We develop an imperative calculus of objects. Its main type con- structor is the one for object types, which incorporate variance annotations and Self types. A subtyping relation between object types supports object subsumption. The type system for objects relies on unusual but beneficial as- sumptions about the possible subtypes of an object type. With the addition of polymorphism, the calculus can express classes and inheritance.\",\n \"Title: Greedy Regular Expression Matching\\nYear: 2004\\n\\nAbstract: This paper studies the problem of matching sequences against regular expressions in order to produce structured values.\",\n \"Title: On process rate semantics\\nYear: 2008\\n\\nAbstract: We provide translations between process algebra and systems of chemical reactions. We show that the translations preserve discrete-state (stochastic) and continuous-state (concentration) semantics, and in particular that the continuous-state semantics of processes corresponds to the differential equations of chemistry based on the law of mass action. The novel semantics of processes so obtained equates processes that have the same state occupation dynamics, but which may have different interaction interfaces.\",\n \"Title: On Subtyping and Matching\\nYear: 1996\\n\\nAbstract: Abstract A relation between recursive object types, called matching , has been proposed as a generalization of subtyping matching does not support subsumption, but it does support inheritance of binary methods We argue that matching is a good idea, but that it should not be regarded as a form of F nally intended) We show that a new interpretation of matching as high er - order subtyping has better properties third - order construction, possibly the only one to have been proposed for general use in programming\",\n \"Title: Persistence and type abstraction\\nYear: 1985\\n\\nAbstract: types are a well known and effective way of structuring programs. The basic ide~ of information hiding can however conflict with the need to store data for long periods of time, ar make it accessible to different activities. In particular a typechecker must be able to recognize fl occurrence of the same abstract type during different activations, and must enforce the privacy, data representations. To achieve this, the persistent storage of data must preserve type information, and mu respect type abstraction. The use of type abstractions in the presence of persistent storage require that abstract types be made persistent as well. Under these conditions, we can preserve ty( security across distinct activations of the typechecker. The following is a brief account of how various models of abstraction and persisten¢ interacL We start by sketching a simple polymorphic language and its types and showing variot ways of modeling type abstraction in such a language. We then discuss some basic notior underlying persistent storage of typed objects, such as the intern and extem primitive and special type dynamic, and describe three persistence strategies. Finally we discuss the partieul~ problem of persistent abstract types.\",\n \"Title: A theory of primitive objects: untyped and first-order systems\\nYear: 1994\\n\\nAbstract: We introduce simple object calculi that support method override and object subsumption. We give an untyped calculus, typing rules, and equational rules. We illustrate the expressiveness of our calculi and the pitfalls that we avoid.\",\n \"Title: On understanding types, data abstraction, and polymorphism\\nYear: 1985\\n\\nAbstract: Our objective is to understand the notion of type in programming languages, present a model of typed, polymorphic programming languages that reflects recent research in type theory, and examine the relevance of recent research to the design of practical programming languages.Object-oriented languages provide both a framework and a motivation for exploring the interaction among the concepts of type, data abstraction, and polymorphism, since they extend the notion of type to data abstraction and since type inheritance is an important form of polymorphism. We develop a &lgr;-calculus-based model for type systems that allows us to explore these interactions in a simple setting, unencumbered by complexities of production programming languages.The evolution of languages from untyped universes to monomorphic and then polymorphic type systems is reviewed. Mechanisms for polymorphism such as overloading, coercion, subtyping, and parameterization are examined. A unifying framework for polymorphic type systems is developed in terms of the typed &lgr;-calculus augmented to include binding of types by quantification as well as binding of values by abstraction.The typed &lgr;-calculus is augmented by universal quantification to model generic functions with type parameters, existential quantification and packaging (information hiding) to model abstract data types, and bounded quantification to model subtypes and type inheritance. In this way we obtain a simple and precise characterization of a powerful type system that includes abstract data types, parametric polymorphism, and multiple inheritance in a single consistent framework. The mechanisms for type checking for the augmented &lgr;-calculus are discussed.The augmented typed &lgr;-calculus is used as a programming language for a variety of illustrative examples. We christen this language Fun because fun instead of &lgr; is the functional abstraction keyword and because it is pleasant to deal with.Fun is mathematically simple and can serve as a basis for the design and implementation of real programming languages with type facilities that are more powerful and expressive than those of existing programming languages. In particular, it provides a basis for the design of strongly typed object-oriented languages.\",\n \"Title: Bitonal membrane systems: Interactions of biological membranes\\nYear: 2008\\n\\nAbstract: Inspired by the alternating orientations of cellular membranes, we describe a structure of nested membranes that are colored in two alternating tones. We investigate a class of reactions that maintain the colored regions largely invariant at each step (bitonal reactions). These coloring constraints guide us towards a small and non-obvious set of basic reactions that are both realistic and complete. They are realistic because bitonality is related to an independent notion of locality, and because similar reactions are implemented by molecular machinery. They are complete because any bitonal reaction can be obtained from them. Such a set of reactions can then be used as the basis for descriptions of biological processes, and in particular for the description of transport networks in cellular biology.\",\n \"Title: An Intuitive Automated Modelling Interface For Systems Biology\\nYear: 2009\\n\\nAbstract: We introduce a natural language interface for building stochastic pi calculus models of biological systems. In this language, complex constructs describing biochemical events are built from basic primitives of association, dissociation and transformation. This language thus allows us to model biochemical systems modularly by describing their dynamics in a narrative-style language, while making amendments, refinements and extensions on the models easy. We demonstrate the language on a model of Fc gamma receptor phosphorylation during phagocytosis. We provide a tool implementation of the translation into a stochastic pi calculus language, Microsoft Research's SPiM. (1 2)\",\n \"Title: Strand algebras for DNA computing\\nYear: 2011\\n\\nAbstract: We present a process algebra for DNA computing, discussing compilation of other formal systems into the algebra, and compilation of the algebra into DNA structures.\",\n \"Title: A semantics of multiple inheritance\\nYear: 1988\\n\\nAbstract: this paper is to present a clean semantics of multiple inheritance and to show that, in the context of strongly-typed, statically-scoped languages, a sound typechecking algorithm exists. Multiple inheritance is also interpreted in a broad sense: instead of being limited to objects, it is extended in a natural way to union types and to higher-order functional types. This constitutes a semantic basis for the unification of functional and object-oriented programming.\",\n \"Title: Algebras and languages for molecular programming\\nYear: 2010\\n\\nAbstract: Nucleic acids (DNA/RNA) encode information digitally, and are currently the only truly 'user-programmable' entities at the molecular scale. They can be used to manufacture nano-scale structures, to produce physical forces, to act as sensors and actuators, and to do computation in between. Eventually we will be able to interface them with biological machinery to detect and cure diseases at the cellular level under program control. The basic technology to create and manipulate these devices has existed for many years, but the imagination necessary to exploit them has been evolving slowly. Recently, some very simple computational schemes have been developed that are autonomous (run on their own once started) and involve only short (easily synthesizable) DNA strands with no other complex molecules.\",\n \"Title: Anytime, anywhere: modal logics for mobile ambients\\nYear: 2000\\n\\nAbstract: The Ambient Calculus is a process calculus where processes may reside within a hierarchy of locations and modify it. The purpose of the calculus is to study mobility, which is seen as the change of spatial configurations over time. In order to describe properties of mobile computations we devise a modal logic that can talk about space as well as time, and that has the Ambient Calculus as a model.\",\n \"Title: A peptide filtering relation quantifies MHC class I peptide optimization.\\nYear: 2011\\n\\nAbstract: Major Histocompatibility Complex (MHC) class I molecules enable cytotoxic T lymphocytes to destroy virus-infected or cancerous cells, thereby preventing disease progression. MHC class I molecules provide a snapshot of the contents of a cell by binding to protein fragments arising from intracellular protein turnover and presenting these fragments at the cell surface. Competing fragments (peptides) are selected for cell-surface presentation on the basis of their ability to form a stable complex with MHC class I, by a process known as peptide optimization. A better understanding of the optimization process is important for our understanding of immunodominance, the predominance of some T lymphocyte specificities over others, which can determine the efficacy of an immune response, the danger of immune evasion, and the success of vaccination strategies. In this paper we present a dynamical systems model of peptide optimization by MHC class I. We incorporate the chaperone molecule tapasin, which has been shown to enhance peptide optimization to different extents for different MHC class I alleles. Using a combination of published and novel experimental data to parameterize the model, we arrive at a relation of peptide filtering, which quantifies peptide optimization as a function of peptide supply and peptide unbinding rates. From this relation, we find that tapasin enhances peptide unbinding to improve peptide optimization without significantly delaying the transit of MHC to the cell surface, and differences in peptide optimization across MHC class I alleles can be explained by allele-specific differences in peptide binding. Importantly, our filtering relation may be used to dynamically predict the cell surface abundance of any number of competing peptides by MHC class I alleles, providing a quantitative basis to investigate viral infection or disease at the cellular level. We exemplify this by simulating optimization of the distribution of peptides derived from Human Immunodeficiency Virus Gag-Pol polyprotein.\",\n \"Title: Squeak: a language for communicating with mice\\nYear: 1985\\n\\nAbstract: Graphical user interfaces are difficult to implement because of the essential concurrency among multiple interaction devices, such as mice, buttons, and keyboards. Squeak is a user interface implementation language that exploits this concurrency rather than hiding it, helping the programmer to express interactions using multiple devices. We present the motivation, design and semantics of squeak. The language is based on concurrent programming constructs but can be compiled into a conventional sequential language; our implementation generates C code. We discuss how squeak programs can be integrated into a graphics system written in a conventional language to implement large but regular user interfaces, and close with a description of the formal semantics.\",\n \"Title: Computational modeling of the EGFR network elucidates control mechanisms regulating signal dynamics.\\nYear: 2009\\n\\nAbstract: BACKGROUND: The epidermal growth factor receptor (EGFR) signaling pathway plays a key role in regulation of cellular growth and development. While highly studied, it is still not fully understood how the signal is orchestrated. One of the reasons for the complexity of this pathway is the extensive network of inter-connected components involved in the signaling. In the aim of identifying critical mechanisms controlling signal transduction we have performed extensive analysis of an executable model of the EGFR pathway using the stochastic pi-calculus as a modeling language. RESULTS: Our analysis, done through simulation of various perturbations, suggests that the EGFR pathway contains regions of functional redundancy in the upstream parts; in the event of low EGF stimulus or partial system failure, this redundancy helps to maintain functional robustness. Downstream parts, like the parts controlling Ras and ERK, have fewer redundancies, and more than 50% inhibition of specific reactions in those parts greatly attenuates signal response. In addition, we suggest an abstract model that captures the main control mechanisms in the pathway. Simulation of this abstract model suggests that without redundancies in the upstream modules, signal transduction through the entire pathway could be attenuated. In terms of specific control mechanisms, we have identified positive feedback loops whose role is to prolong the active state of key components (e.g., MEK-PP, Ras-GTP), and negative feedback loops that help promote signal adaptation and stabilization. CONCLUSIONS: The insights gained from simulating this executable model facilitate the formulation of specific hypotheses regarding the control mechanisms of the EGFR signaling, and further substantiate the benefit to construct abstract executable models of large complex biological networks.\",\n \"Title: A spatial logic for concurrency (part I)\\nYear: 2003\\n\\nAbstract: We present a logic that can express properties of freshness, secrecy, structure, and behavior of concurrent systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to composition, local name restriction, and a primitive fresh name quantifier. Properties can also be defined by recursion; a central aim of this paper is then the combination of a logical notion of freshness with inductive and coinductive definitions of properties.\",\n \"Title: A Spatial Logic for Concurrency (Part II)\\nYear: 2002\\n\\nAbstract: We present a modal logic for describing the spatial organization and the behavior of distributed systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to process composition and name hiding, and a fresh quantifier.\",\n \"Title: Deciding validity in a spatial logic for trees\\nYear: 2005\\n\\nAbstract: We consider a propositional spatial logic for finite trees. The logic includes $\\\\A \\\\Par \\\\B$ (tree composition), $\\\\A \\\\,{\\\\Guarantee}\\\\, \\\\B$ (the implication induced by composition), and $\\\\Zero$ (the unit of composition). We show that the satisfaction and validity problems are equivalent, and decidable. The crux of the argument is devising a finite enumeration of trees to consider when deciding whether a spatial implication is satisfied. We introduce a sequent calculus for the logic, and show it to be sound and complete with respect to an interpretation in terms of satisfaction. Finally, we describe a complete proof procedure for the sequent calculus. We envisage applications in the area of logic-based type systems for semistructured data. We describe a small programming language based on this idea.\",\n \"Title: The Measurable Space of Stochastic Processes\\nYear: 2014\\n\\nAbstract: We introduce a stochastic extension of CCS endowed with structural operational semantics expressed in terms of measure theory. The set of processes is organised as a measurable space by the sigma-algebra generated by structural congruence. The structural operational semantics associates to each process a set of measures over the space of processes. The measures encode the rates of the transitions from a process (state of a system) to a measurable set of processes. We prove that stochastic bisimulation is a congruence that extends structural congruence. In addition to an elegant operational semantics, our calculus provides a canonic way to define metrics on processes that measure that measure how similar two processes are in terms of behaviour.\",\n \"Title: Equational properties of mobile ambients\\nYear: 2003\\n\\nAbstract: The ambient calculus is a process calculus for describing mobile computation. We develop a theory of Morris-style contextual equivalence for proving properties of mobile ambients. We prove a context lemma that allows derivation of contextual equivalences by considering contexts of a particular limited form, rather than all arbitrary contexts. We give an activity lemma that characterises the possible interactions between a process and a context. We prove several examples of contextual equivalence. The proofs depend on characterising reductions in the ambient calculus in terms of a labelled transition system.\",\n \"Title: Biological systems as reactive systems\\nYear: 2005\\n\\nAbstract: Systems Biology is a new discipline aiming to understand the behavior of biological systems as it results from the (non-trivial, ”emergent”) interaction of biological components. We discuss some biological networks that are characterized by simple components, but by complex interactions. The components are separately described in stochastic pi-calculus, which is a ”programming language” that should scale up to description of large systems. The components are then wired together, and their interactions are studied by stochastic simulation. Subtle and unexpected behavior emerges even from simple circuits, and yet stable behavior emerges too, giving some hints about what may be critical and what may be irrelevant in the organization of biological networks.\",\n \"Title: A process model of Rho GTP-binding proteins\\nYear: 2009\\n\\nAbstract: Rho GTP-binding proteins play a key role as molecular switches in many cellular activities. In response to extracellular stimuli and with the help of regulators (GEF, GAP, Effector, GDI), these proteins serve as switches that interact with their environment in a complex manner. Based on the structure of a published ordinary differential equations (ODE) model, we first present a generic process model for the Rho GTP-binding proteins, and compare it with the ODE model. We then extend the basic model to include the behaviour of the GDI regulators and explore the parameter space for the extended model with respect to biological data from the literature. We discuss the challenges this extension brings and the directions of further research. In particular, we present techniques for modular representation and refinement of process models, where, for example, different Rho proteins with different rates for regulator interactions can be given as instances of the same parametric model.\",\n \"Title: Ambient Groups and Mobility Types\\nYear: 2000\\n\\nAbstract: We add name groups and group creation to the typed ambient calculus. Group creation is surprisingly interesting: it has the effect of statically preventing certain communications, and can thus block the accidental or malicious escape of capabilities that is a major concern in practical systems. Moreover, ambient groups allow us to refine our earlier work on type systems for ambient mobility. We present type systems in which groups identify the set of ambients that a process may cross or open.\",\n \"Title: Abstract machines of systems biology\\nYear: 2005\\n\\nAbstract: Living cells are extremely well-organized autonomous systems, consisting of discrete interacting components. Key to understanding and modeling their behavior is modeling their system organization. Four distinct chemical toolkits (classes of macromolecules) have been characterized, each combinatorial in nature. Each toolkit consists of a small number of simple components that are assembled (polymerized) into complex structures that interact in rich ways. Each toolkit abstracts away from chemistry; it embodies an abstract machine with its own instruction set and its own peculiar interaction model. These interaction models are highly effective, but are not ones commonly used in computing: proteins stick together, genes have fixed output, membranes carry activity on their surfaces. Biologists have invented a number of notations attempting to describe these abstract machines and the processes they implement. Moving up from molecular biology, systems biology aims to understand how these interaction models work, separately and together.\",\n \"Title: A graphical representation for biological processes in the stochastic pi-calculus\\nYear: 2006\\n\\nAbstract: This paper presents a graphical representation for the stochastic π-calculus, which is formalised by defining a corresponding graphical calculus. The graphical calculus is shown to be reduction equivalent to stochastic π, ensuring that the two calculi have the same expressive power. The graphical representation is used to model a couple of example biological systems, namely a bistable gene network and a mapk signalling cascade. One of the benefits of the representation is its ability to highlight the existence of cycles, which are a key feature of biological systems. Another benefit is its ability to animate interactions between system components, in order to visualise system dynamics. The graphical representation can also be used as a front end to a simulator for the stochastic π-calculus, to help make modelling and simulation of biological systems more accessible to non computer scientists.\",\n \"Title: A language with distributed scope\\nYear: 1995\\n\\nAbstract: Obliq is a lexically-scoped, untyped, interpreted language that supports distributed object-oriented computation. Obliq objects have state and are local to a site. Obliq computations can roam over the network, while maintaining network connections. Distributed lexical scoping is the key mechanism for managing distributed computation.\",\n \"Title: A theory of primitive objects: second-order systems\\nYear: 1995\\n\\nAbstract: We describe a second-order calculus of objects. The calculus supports object sub- sumption, method override, and the type Self. It is constructed as an extension of System F with subtyping, recursion, and first-order object types.\",\n \"Title: A semantic basis for quest\\nYear: 1990\\n\\nAbstract: Abstract Quest is a ,programming ,language ,based on impredicative, type ,quantifiers and subtyping within a three-level structure of kinds, types and type operators, and values. The semantics of Quest is rather challenging. In particular, difficulties arise when we try to model simultaneously features such as contravariantfunction spaces, record types, subtyping, recursive types, and fixpoints. Inthis paper we describe in detail the type inference rules for Quest, and we give them,meaning ,using a partial ,equivalence ,relation model ,of types. Subtyping is interpreted as in previous work by Bruce and Longo, but the interpretation of some aspects, namely subsumption, power kinds, and record subtyping, is novel. The latter is based on a new encoding of record types. Weconcentrate,on modeling ,quantifiers and subtyping; recursion is the subject of current work. Appears in: Journal of Functional Programming, Vol 1, Part 4, pp.417-458, Cambridge Univ. Press, Oct 1991. SRC Research Report 55, February 14, 1990. Revised January 1, 1993.\",\n \"Title: A Spatial Logic for Concurrency\\nYear: 2001\\n\\nAbstract: We present a logic that can express properties of freshness, secrecy, structure, and behavior of concurrent systems. In addition to standard logical and temporal operators, our logic includes spatial operations corresponding to composition, local name restriction, and a primitive freshname quantifier. Properties can also be defined by recursion; a central theme of this paper is then the combination of a logical notion of freshness with inductive and coinductive definitions of properties.\",\n \"Title: Dynamic Typing in Polymorphic Languages\\nYear: 1995\\n\\nAbstract: Types The interaction between the use of Dynamic and abstract data types gives rise to a puzzling design issue: should the type tag of a dynamically typed value containing an element of an abstract type be matched abstractly or concretely? There are good arguments for both choices: ffl Abstract matching protects the identity of "hidden " representation types and prevents accidental matches in cases where several abstract types happen to have the same representation. ffl Transparent matching...\",\n \"Title: Extensible Grammars for Language Specialization\\nYear: 1993\\n\\nAbstract: A frequent dilemma in the design of a database programming language is the choice between a language with a rich set of tailored notations for schema definitions, query expressions, etc., and a small, simple core language. We address this dilemma by proposing extensible grammars, a syntax-definition formalism for incremental language extensions and restrictions based on an initial core language. The translation of programs written in rich object languages into a small core language is defined via syntax-directed patterns. In contrast to macro-expansion and program-rewriting tools, our extensible grammars respect scoping rules. Therefore, we can introduce binding constructs while avoiding problems with unwanted name clashes. We develop extensible grammars and illustrate their use by extend- ing the lambda calculus with let-bindings, conditionals, and SQL-style query expressions. We then give a formal description of the underlying parsing, transformat,ion, and substitution rules. Finally, we sketch how these rules are exploit,ed in the implementation of a generic, extensible parser package.\",\n \"Title: TQL: a query language for semistructured data based on the ambient logic\\nYear: 2004\\n\\nAbstract: The ambient logic is a modal logic that was proposed for the description of the structural and computational properties of distributed and mobile computation. The structural part of the ambient logic is, essentially, a logic of labelled trees, hence it turns out to be a good foundation for query languages for semistructured data, much in the same way as first-order logic is a fitting foundation for relational query languages. We define here a query language for semistructured data that is based on the ambient logic, and we outline an execution model for this language. The language turns out to be quite expressive. Its strong foundations and the equivalences that hold in the ambient logic are helpful in the definition of the language semantics and execution model.\",\n \"Title: Continuous Markovian Logics - Axiomatization and Quantified Metatheory\\nYear: 2012\\n\\nAbstract: Continuous Markovian Logic (CML) is a multimodal logic that expresses quantitative and qualitative properties of continuous-time labelled Markov processes with arbitrary (analytic) state-spaces, henceforth called continuous Markov processes (CMPs). The modalities of CML evaluate the rates of the exponentially distributed random variables that characterize the duration of the labeled transitions of a CMP. In this paper we present weak and strong complete axiomatizations for CML and prove a series of metaproperties, including the finite model property and the construction of canonical models. CML characterizes stochastic bisimilarity and it supports the definition of a quantified extension of the satisfiability relation that measures the \\\"compatibility\\\" between a model and a property. In this context, the metaproperties allows us to prove two robustness theorems for the logic stating that one can perturb formulas and maintain \\\"approximate satisfaction\\\".\",\n \"Title: Reversibility In Massive Concurrent Systems\\nYear: 2011\\n\\nAbstract: We introduce reversible structures, an algebra for massive concurrent systems, where terms retain bits of causal dependencies that allow one to reverse computation histories. We then study the implementation of (weak coherent) reversible structures in three-domains DNA strands, which is the natural model that has inspired reversible structures. We finally provide schemas for modeling significant synchronization patterns of process algebra into reversible structures and discuss the encoding of asynchronous Reversible CCS.\",\n \"Title: An Universality Result For A (Mem)Brane Calculus Based On Mate/Drip Operations\\nYear: 2006\\n\\nAbstract: Operations with membranes are essential both in brane calculi and in membrane computing. In this paper we take four basic operations from brane calculi, pino, exo, mate, drip, we express them in terms of the membrane computing formalism, and then we investigate the computing power of the P systems using the mate, drip operations as unique evolution rules. All operations are controlled by - and make evolve - multisets of protein-objects embedded in the membranes themselves (not contained in the compartments of the cell, as standard in membrane computing; all compartments delimited by membranes are here empty). Somewhat surprisingly, for systems which use the mate, drip operations we obtain the Turing completeness. The power of P systems based on other operations remains to be investigated.\",\n \"Title: Modern concurrency abstractions for C#\\nYear: 2004\\n\\nAbstract: Polyphonic C♯ is an extension of the C♯ language with new asynchronous concurrency constructs, based on the join calculus. We describe the design and implementation of the language and give examples of its use in addressing a range of concurrent programming problems.\",\n \"Title: Logical properties of name restriction\\nYear: 2001\\n\\nAbstract: We extend the modal logic of ambients described in [7] to the full ambient calculus, including name restriction. We introduce logical operators that can be used to make assertions about restricted names, and we study their properties.\",\n \"Title: From Processes to ODEs by Chemistry\\nYear: 2008\\n\\nAbstract: We investigate the collective behavior of processes in terms of differential equations, using chemistry as a stepping stone. Chemical reactions can be converted to ordinary differential equations, and also to processes in a stochastic process algebra. Conversely, certain stochastic processes (in Chemical Parametric Form, or CPF) can be converted to chemical reactions. CPF is a subset of pi-calculus, but is already more powerful that what is strictly needed to represent chemistry: it supports also parameterization and compositional reuse of models. The mapping of CPF to chemistry thus induces a parametric and compositional mapping of CPF to differential equations; the indirect mapping through chemistry is easier to define and understand than a direct mapping. As an example, we derive a quantitative interleaving law from the differential equations.\",\n \"Title: On the Computational Power of Biochemistry\\nYear: 2008\\n\\nAbstract: We explore the computational power of biochemistry with respect to basic chemistry, identifying complexation as the basic mech- anism that distinguishes the former from the latter. We use two process algebras, the Chemical Ground Form (CGF) which is equivalent to basic chemistry, and the Biochemical Ground Form (BGF) which is a minimal- istic extension of CGF with primitives for complexation. We characterize an expressiveness gap: CGF is not Turing complete while BGF supports a nite precise encoding of Random Access Machines, a well-known Tur- ing powerful formalism.\",\n \"Title: Mobility Types for Mobile Ambients\\nYear: 1999\\n\\nAbstract: An ambient is a named cluster of processes and subambients, whichmoves as a group. The untyped ambient calculus is a process calculusin which ambients model a variety of concepts such as network nodes,packets, channels, and software agents. In these models, some ambientsare intended to be mobile, some immobile; and some are intendedto be ephemeral, some persistent. We describe type systems able toformalize these intentions: they can guarantee that an ambient willremain immobile, and that ...\",\n \"Title: Manipulating Trees with Hidden Labels\\nYear: 2003\\n\\nAbstract: We define an operational semantics and a type system for manipulating semistructured data that contains hidden information. The data model is simple la- beled trees with a hiding operator. Data manipulation is based on pattern matching, with types that track the use of hidden labels.\",\n \"Title: Dynamic typing in a statically typed language\\nYear: 1991\\n\\nAbstract: Statically typed programming languages allow earlier errorchecking, better enforcement of diciplined programming styles, and thegeneration of more efficient object code than languages where all typeconsistency checks are performed at run time. However, even instatically typed languages, there is often the need to deal with datawhose type cannot be determined at compile time. To handlesuch situations safely, we propose to add a typeDynamic whose values are pairs of a valuev and a type tagT where vhas the type denoted by T. Instances ofDynamic are built with an explicittagging construct and inspected with a type safetypecase construct.This paper explores the syntax, operational semantics, and denotational semantics of a simple language that includes the typeDynamic. We give examples of howdynamically typed values can be used in programming. Then we discuss anoperational semantics for our language and obtain a soundness theorem. Wepresent two formulations of the denotational semantics of this languageand relate them to the operational semantics. Finally, we consider theimplications of polymorphism and some implementation issues.\",\n \"Title: A Process Model of Rho GTP-binding Proteins in the Context of Phagocytosis\\nYear: 2008\\n\\nAbstract: At the early stages of the phagocytic signalling, Rho GTP-binding proteins play a key role. With the stimulus from the cell membrane and with the help from the regulators (GEF, GAP, Effector, GDI), these proteins serve as switches that interact with their environment in a complex manner. We present a generic process model for the Rho GTP-binding proteins, and compare it with a previous model that uses ordinary differential equations. We then extend the basic model to include the behaviour of the GDIs. We discuss the challenges this extension brings and directions of further research.\",\n \"Title: Efficient, correct simulation of biological processes in the stochastic pi-calculus\\nYear: 2007\\n\\nAbstract: This paper presents a simulation algorithm for the stochastic π-calculus, designed for the efficient simulation of biological systems with large numbers of molecules. The cost of a simulation depends on the number of species, rather than the number of molecules, resulting in a significant gain in efficiency. The algorithm is proved correct with respect to the calculus, and then used as a basis for implementing the latest version of the SPiM stochastic simulator. The algorithm is also suitable for generating graphical animations of simulations, in order to visualise system dynamics.\",\n \"Title: Invited Talk: A Process Algebra Master Equation\\nYear: 2007\\n\\nAbstract: A Master Equation provides a complete probabilis-tic description of the dynamics of stochastic processes. We give a master equation for a small stochastic process algebra (a subset of CCS with interaction rates). We show that it is equivalent to the standard Chemical Master Equation, connecting our process algebra to the stochastic chemistry of unary and bi-nary reactions.\",\n \"Title: Transitions in programming models: 2\\nYear: 2005\\n\\nAbstract: The future of programming languages is not what it used to be. From the 50's to the 90's, richer, more flexible, and more robust structures were imposed on raw computation. Generally, new models of data and control managed to subsume older ones. But now, as programs and applications expand beyond a single local network and a single administrative domain, the very nature of data and control changes, and many long-lasting conceptual invariants are disrupted. We discuss three of these disruptive changes, which seem to be happening all at the same time, and for related reasons: asynchronous concurrency, semistructured data, and (in much less detail) security abstractions. We outline research project that address issues in those areas, mostly as examples of much larger territories yet to explore.\",\n \"Title: Termination Problems in Chemical Kinetics\\nYear: 2008\\n\\nAbstract: We consider nondeterministic and probabilistic termination problems in a process algebra that is equivalent to basic chemistry. We show that the existence of a terminating computation is decidable, but that termination with any probability strictly greater than zero is undecidable. Moreover, we show that the fairness intrinsic in stochastic computations implies that termination of all computation paths is undecidable, while it is decidable in a nondeterministic framework.\",\n \"Title: Two-Domain DNA Strand Displacement\\nYear: 2013\\n\\nAbstract: We investigate the computing power of a restricted class of DNA strand displacement structures: those that are made of double strands with nicks (interruptions) in the top strand. To preserve this structural invariant, we impose restrictions on the single strands they interact with: we consider only two-domain single strands consisting of one toehold domain and one recognition domain. We study fork and join signal processing gates based on these structures, and show that these systems are amenable to formalisation and mechanical verification.\",\n \"Title: Types for the ambient calculus\\nYear: 2002\\n\\nAbstract: The ambient calculus is a concurrent calculus where the unifying notion of ambient is used to model many different constructs for distributed and mobile computation. We study a type system that describes several properties of ambient behavior. The type system allows ambients to be partitioned in disjoint sets (groups), according to the intended design of a system, in order to specify both the communication and the mobility behavior of ambients.\",\n \"Title: A Compositional Approach to the Stochastic Dynamics of Gene Networks\\nYear: 2005\\n\\nAbstract: We propose a compositional approach to the dynamics of gene regulatory networks based on the stochastic pi-calculus, and develop a representation of gene network elements which can be used to build complex circuits in a transparent and efficient way. To demonstrate the power of the approach we apply it to several artificial networks, such as the repressilator and combinatorial gene circuits first studied in Combinatorial Synthesis of Genetic Networks [1]. For two examples of the latter systems, we point out how the topology of the circuits and the interplay of the stochastic gate interactions influence the circuit behavior. Our approach may be useful for the testing of biological mechanisms proposed to explain the experimentally observed circuit dynamics.\",\n \"Title: From X to Pi; Representing the Classical Sequent Calculus in the Pi-calculus\\nYear: 2011\\n\\nAbstract: We study the Pi-calculus, enriched with pairing and non-blocking input, and define a notion of type assignment that uses the type constructor \\\"arrow\\\". We encode the circuits of the calculus X into this variant of Pi, and show that all reduction (cut-elimination) and assignable types are preserved. Since X enjoys the Curry-Howard isomorphism for Gentzen's calculus LK, this implies that all proofs in LK have a representation in Pi.\",\n \"Title: An extension of system F with subtyping\\nYear: 1991\\n\\nAbstract: System F is a well-known typed λ-calculus with polymorphic types, which provides a basis for polymorphic programming languages. We study an extension of F , called F <: (pronounced ef-sub ), that combines parametric polymorphism with subtyping. The main focus of the paper is the equational theory of F <: , which is related to PER models and the notion of parametricity. We study some categorical properties of the theory when restricted to closed terms, including interesting categorical isomorphisms. We also investigate proof-theoretical properties, such as the conservativity of typing judgments with respect to F . We demonstrate by a set of examples how a range of constructs may be encoded in F <: . These include record operations and subtyping hierarchies that are related to features of object-oriented languages.\",\n \"Title: A Spatial Logic for Querying Graphs\\nYear: 2002\\n\\nAbstract: We study a spatial logic for reasoning about labelled directed graphs, and the application of this logic to provide a query language for analysing and manipulating such graphs. We give a graph description using constructs from process algebra. We introduce a spatial logic in order to reason locally about disjoint subgraphs. We extend our logic to provide a query language which preserves the multiset semantics of our graph model. Our approach contrasts with the more traditional set-based semantics found in query languages such as TQL, Strudel and GraphLog.\",\n \"Title: Turing universality of the biochemical ground form\\nYear: 2010\\n\\nAbstract: We explore the expressive power of languages that naturally model biochemical interactions relative to languages that only naturally model basic chemical reactions, identifying molecular association as the basic mechanism that distinguishes the former from the latter. We use a process algebra, the Biochemical Ground Form (BGF), that adds primitives for molecular association to CGF, which is a process algebra that has been proved to be equivalent to the traditional notations for describing basic chemical reactions. We first observe that, unlike CGF, BGF is Turing universal as it supports a finite precise encoding of Random Access Machines, which comprise a well-known Turing powerful formalism. Then we prove that the Turing universality of BGF derives from the interplay between the molecular primitives of association and dissociation. In fact, the elimination from BGF of the primitives already present in CGF does not reduce the computational strength of the process algebra, but if either association or dissociation is removed, BGF ceases to be Turing complete.\",\n \"Title: Service combinators for Web computing\\nYear: 1999\\n\\nAbstract: The World Wide Web is rich in content and services, but access to these resources must be obtained mostly through manual browsers. We would like to be able to write programs that reproduce human browsing behavior, including reactions to slow transmission-rates and failures on many simultaneous links. We thus introduce a concurrent model that directly incorporates the notions of failure and rate of communication, and then describe programming constructs based on this model.\",\n \"Title: Morphisms of reaction networks that couple structure to function.\\nYear: 2014\\n\\nAbstract: The mechanisms underlying complex biological systems are routinely represented as networks. Network kinetics is widely studied, and so is the connection between network structure and behavior. However, similarity of mechanism is better revealed by relationships between network structures.We define morphisms (mappings) between reaction networks that establish structural connections between them. Some morphisms imply kinetic similarity, and yet their properties can be checked statically on the structure of the networks. In particular we can determine statically that a complex network will emulate a simpler network: it will reproduce its kinetics for all corresponding choices of reaction rates and initial conditions. We use this property to relate the kinetics of many common biological networks of different sizes, also relating them to a fundamental population algorithm.Structural similarity between reaction networks can be revealed by network morphisms, elucidating mechanistic and functional aspects of complex networks in terms of simpler networks.\",\n \"Title: Lineage grammars: describing, simulating and analyzing population dynamics.\\nYear: 2014\\n\\nAbstract: Precise description of the dynamics of biological processes would enable the mathematical analysis and computational simulation of complex biological phenomena. Languages such as Chemical Reaction Networks and Process Algebras cater for the detailed description of interactions among individuals and for the simulation and analysis of ensuing behaviors of populations. However, often knowledge of such interactions is lacking or not available. Yet complete oblivion to the environment would make the description of any biological process vacuous. Here we present a language for describing population dynamics that abstracts away detailed interaction among individuals, yet captures in broad terms the effect of the changing environment, based on environment-dependent Stochastic Tree Grammars (eSTG). It is comprised of a set of stochastic tree grammar transition rules, which are context-free and as such abstract away specific interactions among individuals. Transition rule probabilities and rates, however, can depend on global parameters such as population size, generation count, and elapsed time.We show that eSTGs conveniently describe population dynamics at multiple levels including cellular dynamics, tissue development and niches of organisms. Notably, we show the utilization of eSTG for cases in which the dynamics is regulated by environmental factors, which affect the fate and rate of decisions of the different species. eSTGs are lineage grammars, in the sense that execution of an eSTG program generates the corresponding lineage trees, which can be used to analyze the evolutionary and developmental history of the biological system under investigation. These lineage trees contain a representation of the entire events history of the system, including the dynamics that led to the existing as well as to the extinct individuals.We conclude that our suggested formalism can be used to easily specify, simulate and analyze complex biological systems, and supports modular description of local biological dynamics that can be later used as \\\"black boxes\\\" in a larger scope, thus enabling a gradual and hierarchical definition and simulation of complex biological systems. The simple, yet robust formalism enables to target a broad class of stochastic dynamic behaviors, especially those that can be modeled using global environmental feedback regulation rather than direct interaction between individuals.\",\n \"Title: Phosphorelays Provide Tunable Signal Processing Capabilities for the Cell.\\nYear: 2013\\n\\nAbstract: Achieving a complete understanding of cellular signal transduction requires deciphering the relation between structural and biochemical features of a signaling system and the shape of the signal-response relationship it embeds. Using explicit analytical expressions and numerical simulations, we present here this relation for four-layered phosphorelays, which are signaling systems that are ubiquitous in prokaryotes and also found in lower eukaryotes and plants. We derive an analytical expression that relates the shape of the signal-response relationship in a relay to the kinetic rates of forward, reverse phosphorylation and hydrolysis reactions. This reveals a set of mathematical conditions which, when satisfied, dictate the shape of the signal-response relationship. We find that a specific topology also observed in nature can satisfy these conditions in such a way to allow plasticity among hyperbolic and sigmoidal signal-response relationships. Particularly, the shape of the signal-response relationship of this relay topology can be tuned by altering kinetic rates and total protein levels at different parts of the relay. These findings provide an important step towards predicting response dynamics of phosphorelays, and the nature of subsequent physiological responses that they mediate, solely from topological features and few composite measurements; measuring the ratio of reverse and forward phosphorylation rate constants could be sufficient to determine the shape of the signal-response relationship the relay exhibits. Furthermore, they highlight the potential ways in which selective pressures on signal processing could have played a role in the evolution of the observed structural and biochemical characteristic in phosphorelays.\",\n \"Title: A semantics of object types\\nYear: 1994\\n\\nAbstract: We give a semantics for a typed object calculus, an extension of System F with object subsumption and method over- ride. We interpret the calculus in a per model, proving the soundness of both typing and equational rules. This semantics suggests a syntactic translation from our calculus into a simpler calculus with neither subtyping nor objects. 1. Objects, Records, and Functions Despite the many formal accounts of object-oriented languages, the meaning and the properties of object types remain unclear. In particular, the soundness of object subtyping depends on invariants difficult to capture with standard type constructions; attempts based on record types have been inspiring but not compelling. In order to study object types in a clear setting, we give semantics to an extension of Girard's System F (Girard, Lafont, Taylor 1989) with subtyping, recursion, and some basic object constructs. Like all common object-oriented languages, this calculus supports object subsumption and method override. With subsumption, a new object with more methods can replace an old object transparently. Override is the operation that modifies the behavior of an object, or class, by replacing one of its methods. Neither subsumption nor override is too hard to model in isolation, but their combination has been problematic (see Section 6). Our starting point is the naive view that an object is a record of methods, and that each method is a function. When a method of an object o is invoked, the corresponding function is applied to o. This view of objects as records of functions is often used informally in the literature and it underlies all implementations of standard (single-dispatch) object-oriented languages. In this work, we extend this view to object types. We construct a model based on partial equivalence relations (pers). In our interpretation, objects are records of functions, object types are certain unions of recursive record types, and subtypes are subsets. Along the way, we study unions of pers, and thereby obtain a per semantics for abstract data types and partially abstract data types. We prove the soundness of both typing and equational rules. The per interpretation is direct enough to be informative. In particular, it suggests a syntactic translation from our calculus to a less unconventional extension of System F, with recursion and records, but neither subtyping nor objects. The rest of this introduction describes objects, their intended behavior, and the semantic problems that our approach is designed to solve. Some of this material is borrowed from (Abadi, Cardelli 1994b; Abadi, Cardelli 1994c), where we develop typed and untyped object calculi. We start by describing an untyped calculus that includes object formation, method invocation, and method override. An object is a collection of components (l i=ai i Ï1..n), for distinct labels l i and associated methods a i. The order of these components does not matter. A method is a function having a special parameter, called self. A proper method makes use of its self parameter; a field is a method that ignores self. The letter Ϛ is used as a binder for self, like a special λ binder; Ϛ(x)b is a method with self parameter x and with body b. The object containing a given method is called the method's host object. A method invocation (or selection) is written o.l j, where lj is a label of o. It reduces to the result substituting o for the self parameter in the body of the method named l j. Thus, a method can be applied only to its host object; this invariant is essential for typing objects and for reasoning about them. A method override (or update) is written o.l jfiüϚ(y)b. The intent is to replace the method named l j of o with Ϛ(y)b. Our semantics of override is functional: the result of an override is a copy of the object where the overridden method has been replaced by the new one. This form of method override is more general than usual, in that it applies to objects rather than classes; the generality does not complicate our formal treatment and has advantages in simplicity and expressiveness. We give a direct, informal semantics of objects, viewing them as primitive: Primitive Semantics\",\n \"Title: Gener: a minimal programming module for chemical controllers based on DNA strand displacement.\\nYear: 2015\\n\\nAbstract: Gener is a development module for programming chemical controllers based on DNA strand displacement. Gener is developed with the aim of providing a simple interface that minimizes the opportunities for programming errors: Gener allows the user to test the computations of the DNA programs based on a simple two-domain strand displacement algebra, the minimal available so far. The tool allows the user to perform stepwise computations with respect to the rules of the algebra as well as exhaustive search of the computation space with different options for exploration and visualization. Gener can be used in combination with existing tools, and in particular, its programs can be exported to Microsoft Research's DSD tool as well as to LaTeX.\",\n \"Title: Automated Design and Verification of Localized DNA Computation Circuits\\nYear: 2015\\n\\nAbstract: Simple computations can be performed using the interactions between single-stranded molecules of DNA. These interactions are typically toehold-mediated strand displacement reactions in a well-mixed solution. We demonstrate that a DNA circuit with tethered reactants is a distributed system and show how it can be described as a stochastic Petri net. The system can be verified by mapping the Petri net onto a continuous time Markov chain, which can also be used to find an optimal design for the circuit. This theoretical machinery can be applied to create software that automatically designs a DNA circuit, linking an abstract propositional formula to a physical DNA computation system that is capable of evaluating it.\",\n \"Title: Forward and Backward Bisimulations for Chemical Reaction Networks\\nYear: 2015\\n\\nAbstract: We present two quantitative behavioral equivalences over species of a chemical reaction network (CRN) with semantics based on ordinary differential equations. Forward CRN bisimulation identifies a partition where each equivalence class represents the exact sum of the concentrations of the species belonging to that class. Backward CRN bisimulation relates species that have the identical solutions at all time points when starting from the same initial conditions. Both notions can be checked using only CRN syntactical information, i.e., by inspection of the set of reactions. We provide a unified algorithm that computes the coarsest refinement up to our bisimulations in polynomial time. Further, we give algorithms to compute quotient CRNs induced by a bisimulation. As an application, we find significant reductions in a number of models of biological processes from the literature. In two cases we allow the analysis of benchmark models which would be otherwise intractable due to their memory requirements.\",\n \"Title: Stochastic Analysis of Chemical Reaction Networks Using Linear Noise Approximation\\nYear: 2015\\n\\nAbstract: Stochastic evolution of Chemical Reactions Networks (CRNs) over time is usually analyzed through solving the Chemical Master Equation (CME) or performing extensive simulations. Analysing stochasticity is often needed, particularly when some molecules occur in low numbers. Unfortunately, both approaches become infeasible if the system is complex and/or it cannot be ensured that initial populations are small. We develop a probabilistic logic for CRNs that enables stochastic analysis of the evolution of populations of molecular species. We present an approximate model checking algorithm based on the Linear Noise Approximation (LNA) of the CME, whose computational complexity is independent of the population size of each species and polynomial in the number of different species. The algorithm requires the solution of first order polynomial differential equations. We prove that our approach is valid for any CRN close enough to the thermodynamical limit. However, we show on four case studies that it can still provide good approximation even for low molecule counts. Our approach enables rigorous analysis of CRNs that are not analyzable by solving the CME, but are far from the deterministic limit. Moreover, it can be used for a fast approximate stochastic characterization of a CRN.\",\n \"Title: Symbolic computation of differential equivalences.\\nYear: 2016\\n\\nAbstract: Ordinary differential equations (ODEs) are widespread in many natural sciences including chemistry, ecology, and systems biology, and in disciplines such as control theory and electrical engineering. Building on the celebrated molecules-as-processes paradigm, they have become increasingly popular in computer science, with high-level languages and formal methods such as Petri nets, process algebra, and rule-based systems that are interpreted as ODEs. We consider the problem of comparing and minimizing ODEs automatically. Influenced by traditional approaches in the theory of programming, we propose differential equivalence relations. We study them for a basic intermediate language, for which we have decidability results, that can be targeted by a class of high-level specifications. An ODE implicitly represents an uncountable state space, hence reasoning techniques cannot be borrowed from established domains such as probabilistic programs with finite-state Markov chain semantics. We provide novel symbolic procedures to check an equivalence and compute the largest one via partition refinement algorithms that use satisfiability modulo theories. We illustrate the generality of our framework by showing that differential equivalences include (i) well-known notions for the minimization of continuous-time Markov chains (lumpability), (ii)~bisimulations for chemical reaction networks recently proposed by Cardelli et al., and (iii) behavioral relations for process algebra with ODE semantics. With a prototype implementation we are able to detect equivalences in biochemical models from the literature that cannot be reduced using competing automatic techniques.\",\n \"Title: Efficient Syntax-Driven Lumping of Differential Equations.\\nYear: 2016\\n\\nAbstract: We present an algorithm to compute exact aggregations of a class of systems of ordinary differential equations ODEs. Our approach consists in an extension of Paige and Tarjan's seminal solution to the coarsest refinement problem by encoding an ODE system into a suitable discrete-state representation. In particular, we consider a simple extension of the syntax of elementary chemical reaction networks because i it can express ODEs with derivatives given by polynomials of degree at most two, which are relevant in many applications in natural sciences and engineering; and ii we can build on two recently introduced bisimulations, which yield two complementary notions of ODE lumping. Our algorithm computes the largest bisimulations in $$Or \\\\\\\\cdot s \\\\\\\\cdot \\\\\\\\log s$$ time, where r is the number of monomials and s is the number of variables in the ODEs. Numerical experiments on real-world models from biochemistry, electrical engineering, and structural mechanics show that our prototype is able to handle ODEs with millions of variables and monomials, providing significant model reductions.\",\n \"Title: Chemical Reaction Network Designs for Asynchronous Logic Circuits.\\nYear: 2018\\n\\nAbstract: Chemical reaction networks (CRNs) are a versatile language for describing the dynamical behaviour of chemical kinetics, capable of modelling a variety of digital and analogue processes. While CRN designs for synchronous sequential logic circuits have been proposed and their implementation in DNA demonstrated, a physical realisation of these devices is difficult because of their reliance on a clock. Asynchronous sequential logic, on the other hand, does not require a clock, and instead relies on handshaking protocols to ensure the temporal ordering of different phases of the computation. This paper provides novel CRN designs for the construction of asynchronous logic, arithmetic and control flow elements based on a bi-molecular reaction motif with catalytic reactions and uniform reaction rates. We model and validate the designs for the deterministic and stochastic semantics using Microsoft’s GEC tool and the probabilistic model checker PRISM, demonstrating their ability to emulate the function of asynchronous components under low molecular count.\",\n \"Title: Approximation Of Probabilistic Reachability For Chemical Reaction Networks Using The Linear Noise Approximation\\nYear: 2016\\n\\nAbstract: We study time-bounded probabilistic reachability for Chemical Reaction Networks (CRNs) using the Linear Noise Approximation (LNA). The LNA approximates the discrete stochastic semantics of a CRN in terms of a continuous space Gaussian process. We consider reachability regions expressed as intersections of finitely many linear inequalities over the species of a CRN. This restriction allows us to derive an abstraction of the original Gaussian process as a time-inhomogeneous discrete-time Markov chain (DTMC), such that the dimensionality of its state space is independent of the number of species of the CRN, ameliorating the state space explosion problem. We formulate an algorithm for approximate computation of time-bounded reachability probabilities on the resulting DTMC and show how to extend it to more complex temporal properties. We implement the algorithm and demonstrate on two case studies that it permits fast and scalable computation of reachability properties with controlled accuracy.\",\n \"Title: Reachability Computation for Switching Diffusions: Finite Abstractions with Certifiable and Tuneable Precision.\\nYear: 2017\\n\\nAbstract: We consider continuous time stochastic hybrid systems with no resets and continuous dynamics described by linear stochastic differential equations -- models also known as switching diffusions. We show that for this class of models reachability (and dually, safety) properties can be studied on an abstraction defined in terms of a discrete time and finite space Markov chain (DTMC), with provable error bounds. The technical contribution of the paper is a characterization of the uniform convergence of the time discretization of such stochastic processes with respect to safety properties. This allows us to newly provide a complete and sound numerical procedure for reachability and safety computation over switching diffusions.\",\n \"Title: ERODE: A Tool for the Evaluation and Reduction of Ordinary Differential Equations.\\nYear: 2017\\n\\nAbstract: We present ERODE, a multi-platform tool for the solution and exact reduction of systems of ordinary differential equations ODEs. ERODE supports two recently introduced, complementary, equivalence relations over ODE variables: forward differential equivalence yields a self-consistent aggregate system where each ODE gives the cumulative dynamics of the sum of the original variables in the respective equivalence class. Backward differential equivalence identifies variables that have identical solutions whenever starting from the same initial conditions. As back-end ERODE uses the well-known Z3 SMT solver to compute the largest equivalence that refines a given initial partition of ODE variables. In the special case of ODEs with polynomial derivatives of degree at most two covering affine systems and elementary chemical reaction networks, it implements a more efficient partition-refinement algorithm in the style of Paige and Tarjan. ERODE comes with a rich development environment based on the Eclipse plug-in framework offering: i seamless project management; ii a fully-featured text editor; and iii importing-exporting capabilities.\",\n \"Title: Syntactic Markovian Bisimulation for Chemical Reaction Networks.\\nYear: 2017\\n\\nAbstract: In chemical reaction networks (CRNs) with stochastic semantics based on continuous-time Markov chains (CTMCs), the typically large populations of species cause combinatorially large state spaces. This makes the analysis very difficult in practice and represents the major bottleneck for the applicability of minimization techniques based, for instance, on lumpability. In this paper we present syntactic Markovian bisimulation (SMB), a notion of bisimulation developed in the Larsen-Skou style of probabilistic bisimulation, defined over the structure of a CRN rather than over its underlying CTMC. SMB identifies a lumpable partition of the CTMC state space a priori, in the sense that it is an equivalence relation over species implying that two CTMC states are lumpable when they are invariant with respect to the total population of species within the same equivalence class. We develop an efficient partition-refinement algorithm which computes the largest SMB of a CRN in polynomial time in the number of species and reactions. We also provide an algorithm for obtaining a quotient network from an SMB that induces the lumped CTMC directly, thus avoiding the generation of the state space of the original CRN altogether. In practice, we show that SMB allows significant reductions in a number of models from the literature. Finally, we study SMB with respect to the deterministic semantics of CRNs based on ordinary differential equations (ODEs), where each equation gives the time-course evolution of the concentration of a species. SMB implies forward CRN bisimulation, a recently developed behavioral notion of equivalence for the ODE semantics, in an analogous sense: it yields a smaller ODE system that keeps track of the sums of the solutions for equivalent species.\",\n \"Title: Maximal Aggregation Of Polynomial Dynamical Systems\\nYear: 2017\\n\\nAbstract: Ordinary differential equations (ODEs) with polynomial derivatives are a fundamental tool for understanding the dynamics of systems across many branches of science, but our ability to gain mechanistic insight and effectively conduct numerical evaluations is critically hindered when dealing with large models. Here we propose an aggregation technique that rests on two notions of equivalence relating ODE variables whenever they have the same solution (backward criterion) or if a self-consistent system can be written for describing the evolution of sums of variables in the same equivalence class (forward criterion). A key feature of our proposal is to encode a polynomial ODE system into a finitary structure akin to a formal chemical reaction network. This enables the development of a discrete algorithm to efficiently compute the largest equivalence, building on approaches rooted in computer science to minimize basic models of computation through iterative partition refinements. The physical interpretability of the aggregation is shown on polynomial ODE systems for biochemical reaction networks, gene regulatory networks, and evolutionary game theory.\",\n \"Title: Efficient Switches in Biology and Computer Science.\\nYear: 2017\\n\\nAbstract: Biological systems are adapted to respond quickly to changes in their environment. Signal processing often leads to all-or-none switch-like activation of downstream pathways. Such biological switches are based on molecular interactions that form positive feedback loops. Proper signal processing and switching have to be made by the noisy interactions of fluctuating molecular components; still, switching has to happen quickly once a threshold in the input signal is reached. Several computing algorithms have been designed to perform similar all-or-none decisions with high efficiency. We discuss here how the structure and dynamical features of a computational algorithm resemble the behaviour of a large class of biological switches and what makes them work efficiently. Furthermore, we highlight what biologists can learn by looking at specific features of computational algorithms.\",\n \"Title: Central Limit Model Checking.\\nYear: 2018\\n\\nAbstract: We consider probabilistic model checking for continuous-time Markov chains (CTMCs) induced from Stochastic Reaction Networks against a fragment of Continuous Stochastic Logic (CSL) extended with reward operators. Classical numerical algorithms for CSL model checking based on uniformisation are limited to finite CTMCs and suffer from exponential growth of the state space with respect to the number of species. However, approximate techniques such as mean-field approximations and simulations combined with statistical inference are more scalable but can be time-consuming and do not support the full expressiveness of CSL. In this article, we employ a continuous-space approximation of the CTMC in terms of a Gaussian process based on the Central Limit Approximation, also known as the Linear Noise Approximation, whose solution requires solving a number of differential equations that is quadratic in the number of species and independent of the population size. We then develop efficient and scalable approximate model checking algorithms on the resulting Gaussian process, where we restrict the target regions for probabilistic reachability to convex polytopes. This allows us to derive an abstraction in terms of a time-inhomogeneous discrete-time Markov chain (DTMC), whose dimension is independent of the number of species, on which model checking is performed. Using results from probability theory, we prove the convergence in distribution of our algorithms to the corresponding measures on the original CTMC. We implement the techniques and, on a set of examples, demonstrate that they allow us to overcome the state space explosion problem, while still correctly characterizing the stochastic behaviour of the system. Our methods can be used for formal analysis of a wide range of distributed stochastic systems, including biochemical systems, sensor networks, and population protocols.\",\n \"Title: Single molecules can operate as primitive biological sensors, switches and oscillators.\\nYear: 2018\\n\\nAbstract: We propose that evolution could have converted this switch into a single molecule oscillator, which could have been used as a primitive timekeeper. We discuss how the structure of the simplest known circadian clock regulatory system, found in cyanobacteria, resembles the proposed single molecule oscillator. Besides, we speculate if such minimal systems could have existed in an RNA world.\",\n \"Title: Robustness Guarantees for Bayesian Inference with Gaussian Processes\\nYear: 2018\\n\\nAbstract: Bayesian inference and Gaussian processes are widely used in applications ranging from robotics and control to biological systems. Many of these applications are safety-critical and require a characterization of the uncertainty associated with the learning model and formal guarantees on its predictions. In this paper we define a robustness measure for Bayesian inference against input perturbations, given by the probability that, for a test point and a compact set in the input space containing the test point, the prediction of the learning model will remain delta - close for all the points in the set, for delta > 0. Such measures can be used to provide formal probabilistic guarantees for the absence of adversarial examples. By employing the theory of Gaussian processes, we derive upper bounds on the resulting robustness by utilising the Borell-TIS inequality, and propose algorithms for their computation. We evaluate our techniques on two examples, a GP regression problem and a fully-connected deep neural network, where we rely on weak convergence to GPs to study adversarial examples on the MNIST dataset.\",\n \"Title: Computing with biological switches and clocks.\\nYear: 2018\\n\\nAbstract: The complex dynamics of biological systems is primarily driven by molecular interactions that underpin the regulatory networks of cells. These networks typically contain positive and negative feedback loops, which are responsible for switch-like and oscillatory dynamics, respectively. Many computing systems rely on switches and clocks as computational modules. While the combination of such modules in biological systems leads to a variety of dynamical behaviours, it is also driving development of new computing algorithms. Here we present a historical perspective on computation by biological systems, with a focus on switches and clocks, and discuss parallels between biology and computing. We also outline our vision for the future of biological computing.\",\n \"Title: Efficiency through Uncertainty: Scalable Formal Synthesis for Stochastic Hybrid Systems.\\nYear: 2019\\n\\nAbstract: This work targets the development of an efficient abstraction method for formal analysis and control synthesis of discrete-time stochastic hybrid systems (SHS) with linear dynamics. The focus is on temporal logic specifications over both finite- and infinite-time horizons. The framework constructs a finite abstraction as a class of uncertain Markov models known as interval Markov decision process (IMDP). Then, a strategy that maximizes the satisfaction probability of the given specification is synthesized over the IMDP and mapped to the underlying SHS. In contrast to existing formal approaches, which are by and large limited to finite-time properties and rely on conservative over-approximations, we show that the exact abstraction error can be computed as a solution of convex optimization problems and can be embedded into the IMDP abstraction. This is later used in the synthesis step over both bounded- and unbounded-time properties, mitigating the known state-space explosion problem. Our experimental validation of the new approach compared to existing abstraction-based approaches shows: (i) significant (orders of magnitude) reduction of the abstraction error; (ii) marked speed-ups; and (iii) boosted scalability, allowing in particular to verify models with more than 10 continuous variables.\",\n \"Title: Secrecy and group creation\\nYear: 2005\\n\\nAbstract: We add an operation of group creation to the typed π-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. Intuitively, no channel belonging to a fresh group can be received by processes outside the initial scope of the group, even if those processes are untyped. We formalize this intuition by adapting a notion of secrecy introduced by Abadi, and proving a preservation of secrecy property.\",\n \"Title: Programming Discrete Distributions with Chemical Reaction Networks.\\nYear: 2016\\n\\nAbstract: We explore the range of probabilistic behaviours that can be engineered with Chemical Reaction Networks (CRNs). We give methods to “program” CRNs so that their steady state is chosen from some desired target distribution that has finite support in , with . Moreover, any distribution with countable infinite support can be approximated with arbitrarily small error under the norm. We also give optimized schemes for special distributions, including the uniform distribution. Finally, we formulate a calculus to compute on distributions that is complete for finite support distributions, and can be compiled to a restricted class of CRNs that at steady state realize those distributions.\",\n \"Title: Comparing Chemical Reaction Networks: A Categorical and Algorithmic Perspective.\\nYear: 2016\\n\\nAbstract: We study chemical reaction networks (CRNs) as a kernel language for concurrency models with semantics based on ordinary differential equations. We investigate the problem of comparing two CRNs, i.e., to decide whether the trajectories of a source CRN can be matched by a target CRN under an appropriate choice of initial conditions. Using a categorical framework, we extend and relate model-comparison approaches based on structural (syntactic) and on dynamical (semantic) properties of a CRN, proving their equivalence. Then, we provide an algorithm to compare CRNs, running linearly in time with respect to the cardinality of all possible comparisons. Finally, we apply our results to biological models from the literature.\",\n \"Title: Statistical Guarantees for the Robustness of Bayesian Neural Networks.\\nYear: 2019\\n\\nAbstract: We introduce a probabilistic robustness measure for Bayesian Neural Networks (BNNs), defined as the probability that, given a test point, there exists a point within a bounded set such that the BNN prediction differs between the two. Such a measure can be used, for instance, to quantify the probability of the existence of adversarial examples. Building on statistical verification techniques for probabilistic models, we develop a framework that allows us to estimate probabilistic robustness for a BNN with statistical guarantees, i.e., with a priori error and confidence bounds. We provide experimental comparison for several approximate BNN inference techniques on image classification tasks associated to MNIST and a two-class subset of the GTSRB dataset. Our results enable quantification of uncertainty of BNN predictions in adversarial settings.\",\n \"Title: Robustness Quantification for Classification with Gaussian Processes.\\nYear: 2019\\n\\nAbstract: We consider Bayesian classification with Gaussian processes (GPs) and define robustness of a classifier in terms of the worst-case difference in the classification probabilities with respect to input perturbations. For a subset of the input space $T\\\\subseteq \\\\mathbb{R}^m$ such properties reduce to computing the infimum and supremum of the classification probabilities for all points in $T$. Unfortunately, computing the above values is very challenging, as the classification probabilities cannot be expressed analytically. Nevertheless, using the theory of Gaussian processes, we develop a framework that, for a given dataset $\\\\mathcal{D}$, a compact set of input points $T\\\\subseteq \\\\mathbb{R}^m$ and an error threshold $\\\\epsilon>0$, computes lower and upper bounds of the classification probabilities by over-approximating the exact range with an error bounded by $\\\\epsilon$. We provide experimental comparison of several approximate inference methods for classification on tasks associated to MNIST and SPAM datasets showing that our results enable quantification of uncertainty in adversarial classification settings.\",\n \"Title: Lumpability For Uncertain Continuous-Time Markov Chains\\nYear: 2021\\n\\nAbstract: The assumption of perfect knowledge of rate parameters in continuous-time Markov chains (CTMCs) is undermined when confronted with reality, where they may be uncertain due to lack of information or because of measurement noise. In this paper we consider uncertain CTMCs, where rates are assumed to vary non-deterministically with time from bounded continuous intervals. This leads to a semantics which associates each state with the reachable set of its probability under all possible choices of the uncertain rates. We develop a notion of lumpability which identifies a partition of states where each block preserves the reachable set of the sum of its probabilities, essentially lifting the well-known CTMC ordinary lumpability to the uncertain setting. We proceed with this analogy with two further contributions: a logical characterization of uncertain CTMC lumping in terms of continuous stochastic logic; and a polynomial time and space algorithm for the minimization of uncertain CTMCs by partition refinement, using the CTMC lumping algorithm as an inner step. As a case study, we show that the minimizations in a substantial number of CTMC models reported in the literature are robust with respect to uncertainties around their original, fixed, rate values.\",\n \"Title: A Language for Modeling and Optimizing Experimental Biological Protocols\\nYear: 2021\\n\\nAbstract: Automation is becoming ubiquitous in all laboratory activities, moving towards precisely defined and codified laboratory protocols. However, the integration between laboratory protocols and mathematical models is still lacking. Models describe physical processes, while protocols define the steps carried out during an experiment: neither cover the domain of the other, although they both attempt to characterize the same phenomena. We should ideally start from an integrated description of both the model and the steps carried out to test it, to concurrently analyze uncertainties in model parameters, equipment tolerances, and data collection. To this end, we present a language to model and optimize experimental biochemical protocols that facilitates such an integrated description, and that can be combined with experimental data. We provide probabilistic semantics for our language in terms of Gaussian processes (GPs) based on the linear noise approximation (LNA) that formally characterizes the uncertainties in the data collection, the underlying model, and the protocol operations. In a set of case studies, we illustrate how the resulting framework allows for automated analysis and optimization of experimental protocols, including Gibson assembly protocols.</p>\",\n \"Title: On the Design of a PID Bio-Controller With Set Point Weighting and Filtered Derivative Action\\nYear: 2022\\n\\nAbstract: Effective and robust regulation of biomolecular processes is crucial for designing reliable synthetic bio-devices functioning in uncertain and constantly changing biological environments. Proportional-Integral-Derivative (PID) controllers are undeniably the most common way of implementing feedback control in modern technological applications. Here, we introduce a highly tunable PID bio-controller with set point weighting and filtered derivative action presented as a chemical reaction network with mass action kinetics. To demonstrate its effectiveness, we apply our PID scheme on a simple biological process of two mutually activated species, one of which is assumed to be the output of interest. To highlight its performance advantages we compare it to PI regulation using numerical simulations in both the deterministic and stochastic setting.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":115,"string":"115"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13380,"string":"13,380"}}},{"rowIdx":13381,"cells":{"question_id":{"kind":"string","value":"Jan stergaard"},"question":{"kind":"string","value":"Generate an abstract for the title \"Reconstruction of Undersampled Atomic Force Microscopy Images: Interpolation versus Basis Pursuit\" using the following items: Atomic force microscopy, high-resolution imaging, nanoscale matter, under sampling, image reconstruction."},"answer":{"kind":"string","value":"Atomic force microscopy (AFM) is one of the most advanced tools for high-resolution imaging and manipulation of nanoscale matter. Unfortunately, standard AFM imaging requires a timescale on the order of seconds to minutes to acquire an image which makes it complicated to observe dynamic processes. Moreover, it is often required to take several images before a relevant observation region is identified. In this paper we show how to significantly reduce the image acquisition time by under sampling. The reconstruction of an under sampled AFM image can be viewed as an in painting, interpolating problem, or a special case of compressed sensing. We argue that the preferred approach depends upon the type of image. Of the methods proposed for AFM, images containing high frequencies should be reconstructed using basis pursuit from data collected in a spiral pattern. Images without too much high frequency content should be reconstructed using interpolation."},"correct_answer":{"kind":"string","value":"Atomic force microscopy (AFM) is one of the most advanced tools for high-resolution imaging and manipulation of nanoscale matter. Unfortunately, standard AFM imaging requires a timescale on the order of seconds to minutes to acquire an image which makes it complicated to observe dynamic processes. Moreover, it is often required to take several images before a relevant observation region is identified. In this paper we show how to significantly reduce the image acquisition time by under sampling. The reconstruction of an under sampled AFM image can be viewed as an in painting, interpolating problem, or a special case of compressed sensing. We argue that the preferred approach depends upon the type of image. Of the methods proposed for AFM, images containing high frequencies should be reconstructed using basis pursuit from data collected in a spiral pattern. Images without too much high frequency content should be reconstructed using interpolation."},"documents":{"kind":"list like","value":["Title: Correction to \"Packetized Predictive Control of Stochastic Systems Over Bit-Rate Limited Channels With Packet Loss\".\nYear: 2013\n\nAbstract: The authors correct the results in Section V of the above-named article (ibid., vol. 56, no. 12, pp. 2854-2868, Dec. 2011).","Title: Achieving the Quadratic Gaussian Rate-Distortion Function for Source Uncorrelated Distortions\nYear: 2008\n\nAbstract: We prove achievability of the recently characterized quadratic Gaussian\nrate-distortion function (RDF) subject to the constraint that the distortion is\nuncorrelated to the source. This result is based on shaped dithered lattice\nquantization in the limit as the lattice dimension tends to infinity and holds\nfor all positive distortions. It turns out that this uncorrelated distortion\nRDF can be realized causally. This feature, which stands in contrast to\nShannon's RDF, is illustrated by causal transform coding. Moreover, we prove\nthat by using feedback noise shaping the uncorrelated distortion RDF can be\nachieved causally and with memoryless entropy coding. Whilst achievability\nrelies upon infinite dimensional quantizers, we prove that the rate loss\nincurred in the finite dimensional case can be upper-bounded by the space\nfilling loss of the quantizer and, thus, is at most 0.254 bit/dimension.","Title: Ripple design of LT codes for AWGN channel.\nYear: 2012\n\nAbstract: In this paper, we present an analytical framework for designing LT codes in additive white Gaussian noise (AWGN) channels. We show that some of analytical results from binary erasure channels (BEC) also hold in AWGN channels with slight modifications. This enables us to apply a ripple-based design approach, which until now has only been used in the BEC. LT codes designed by this way show promising performance which is near the Shannon limit even with short codewords.","Title: Ripple Design of LT Codes for BIAWGN Channels.\nYear: 2014\n\nAbstract: This paper presents a novel framework, which enables a design of rateless codes for binary input additive white Gaussian noise (BIAWGN) channels, using the ripple-based approach known from the works for the binary erasure channel (BEC). We reveal that several aspects of the analytical results from the BEC also hold in BIAWGN channels. The presented framework is applied in a code design example, which shows promising results compared to existing work. In particular it shows a great robustness towards variations in the signal-to-noise power ratio (SNR), contrary to existing codes.","Title: Multiple Description Coding with Feedback Based Network Compression\nYear: 2010\n\nAbstract: This paper concerns multi path video streaming using adaptive multiple description coding. The adaptation leverages on the fact that multiple descriptions are correlated. Thus if an intermediate node gets feedback telling that another path is likely to deliver a description, this node can compress its description and forward it. Such a compression can also be done already at the source node; however, the feedback arrives more timely and reliably to intermediate nodes that are closer to the final receiver. In this paper we investigate the performance of such adaptation at the source node and an intermediate node, respectively. A trade-off exists between reducing the delay of the feedback by adapting in the vicinity of the receiver and increasing the gain from compression by adapting close to the source. The analysis shows that adaptation in the network provides a better trade-off than adaptation at the source. Schemes which provide simple solutions to adaptation both at the source and in the network are proposed, analyzed, simulated and compared to non-adaptive reference schemes in scenarios that involve last hop that is wireless. The results reveal that the proposed compression schemes offer significant benefits in streaming scenarios.","Title: Power Control and Coding Formulation for State Estimation with Wireless Sensors.\nYear: 2014\n\nAbstract: Technological advances made wireless sensors cheap and reliable enough to be brought into industrial use. A major challenge arises from the fact that wireless channels introduce random packet dropouts. Power control and coding are key enabling technologies in wireless communications to ensure efficient communication. In this paper, we examine the role of power control and coding for Kalman filtering over wireless correlated channels. Two estimation architectures are considered; initially, the sensors send their measurements directly to a single gateway (GW). Next, wireless relay nodes provide additional links. The GW decides on the coding scheme and the transmitter power levels of the wireless nodes. The decision process is carried out online and adapts to varying channel conditions to improve the tradeoff between state estimation accuracy and energy expenditure. In combination with predictive power control, we investigate the use of multiple-description coding (MDC), zero-error coding (ZEC), and network coding and provide sufficient conditions for the expectation of the estimation error covariance matrix to be bounded. Numerical results suggest that the proposed method may lead to energy savings of around 50%, when compared with an alternative scheme, wherein transmission power levels and bit-rates are governed by simple logic. In particular, ZEC is preferable at time instances with high channel gains, whereas MDC is superior for time instances with low gains. When channels between the sensors and the GW are in deep fades, network coding improves estimation accuracy significantly without sacrificing energy efficiency.","Title: UEP LT Codes with Intermediate Feedback.\nYear: 2013\n\nAbstract: We analyze a class of rateless codes, called Luby transform (LT) codes with unequal error protection (UEP). We show that while these codes successfully provide UEP, there is a significant price in terms of redundancy in the lower prioritized segments. We propose a modification with a single intermediate feedback message. Our analysis shows a dramatic improvement on the decoding performance of the lower prioritized segment.","Title: A Framework for Control System Design Subject to Average Data-Rate Constraints.\nYear: 2011\n\nAbstract: This paper studies discrete-time control systems subject to average data-rate limits. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source-coding scheme (with unity signal transfer function) has to be deployed in the feedback path. For this situation, and by focusing on a class of source-coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. As an illustration of the uses of our framework, we apply it to study the interplay between stability and average data-rates in the considered architecture. It is shown that the proposed class of coding schemes can achieve mean square stability at average data-rates that are, at most, 1.254 bits per sample away from the absolute minimum rate for stability established by Nair and Evans. This rate penalty is compensated by the simplicity of our approach.","Title: The Quadratic Gaussian Rate-Distortion Function for Source Uncorrelated Distortions\nYear: 2008\n\nAbstract: We characterize the rate-distortion function for zero-mean stationary Gaussian sources under the MSE fidelity criterion and subject to the additional constraint that the distortion is uncorrelated to the input. The solution is given by two equations coupled through a single scalar parameter. This has a structure similar to the well known water-filling solution obtained without the uncorrelated distortion restriction. Our results fully characterize the unique statistics of the optimal distortion. We also show that, for all positive distortions, the minimum achievable rate subject to the uncorrelation constraint is strictly larger than that given by the un-constrained rate-distortion function. This gap increases with the distortion and tends to infinity and zero, respectively, as the distortion tends to zero and infinity.","Title: Sparse command generator for remote control\nYear: 2011\n\nAbstract: In this article, we consider remote-controlled systems, where the command generator and the controlled object are connected with a bandwidth-limited communication link. In the remote-controlled systems, efficient representation of control commands is one of the crucial issues because of the bandwidth limitations of the link. We propose a new representation method for control commands based on compressed sensing. In the proposed method, compressed sensing reduces the number of bits in each control signal by representing it as a sparse vector. The compressed sensing problem is solved by an ℓ1-ℓ2 optimization, which can be effectively implemented with an iterative shrinkage algorithm. A design example also shows the effectiveness of the proposed method.","Title: l1 Compression of Image Sequences Using the Structural Similarity Index Measure\nYear: 2009\n\nAbstract: We consider lossy compression of image sequences using l1-compression with overcomplete dictionaries. As a fidelity measure for the reconstruction quality, we incorporate the recently proposed structural similarity index measure, and we show that this leads to problem formulations that are very similar to conventional l1 compression algorithms. In addition, we develop efficient large-scale algorithms used for joint encoding of multiple image frames.","Title: n-channel entropy-constrained multiple-description lattice vector quantization\nYear: 2006\n\nAbstract: In this paper, we derive analytical expressions for the central and side quantizers which, under high-resolution assumptions, minimize the expected distortion of a symmetric multiple-description lattice vector quantization (MD-LVQ) system subject to entropy constraints on the side descriptions for given packet-loss probabilities. We consider a special case of the general n-channel symmetric multiple-description problem where only a single parameter controls the redundancy tradeoffs between the central and the side distortions. Previous work on two-channel MD-LVQ showed that the distortions of the side quantizers can be expressed through the normalized second moment of a sphere. We show here that this is also the case for three-channel MD-LVQ. Furthermore, we conjecture that this is true for the general n-channel MD-LVQ. For given source, target rate, and packet-loss probabilities we find the optimal number of descriptions and construct the MD-LVQ system that minimizes the expected distortion. We verify theoretical expressions by numerical simulations and show in a practical setup that significant performance improvements can be achieved over state-of-the-art two-channel MD-LVQ by using three-channel MD-LVQ.","Title: Energy efficient state estimation with wireless sensors through the use of predictive power control and coding\nYear: 2010\n\nAbstract: We study state estimation via wireless sensors over fading channels. Packet loss probabilities depend upon time-varying channel gains, packet lengths and transmission power levels of the sensors. Measurements are coded into packets by using either independent coding or distributed zero-error coding. At the gateway, a time-varying Kalman filter uses the received packets to provide the state estimates. To trade sensor energy expenditure for state estimation accuracy, we develop a predictive control algorithm which, in an online fashion, determines the transmission power levels and codebooks to be used by the sensors. To further conserve sensor energy, the controller is located at the gateway and sends coarsely quantized power increment commands, only whenever deemed necessary. Simulations based on real channel measurements illustrate that the proposed method gives excellent results.","Title: Fixed-Lag Smoothing for Low-Delay Predictive Coding with Noise Shaping for Lossy Networks\nYear: 2010\n\nAbstract: We consider linear predictive coding and noise shaping for coding and transmission of auto-regressive (AR) sources over lossy networks. We generalize an existing framework to arbitrary filter orders and propose use of fixed-lag smoothing at the decoder, in order to further reduce the impact of transmission failures. We show that fixed-lag smoothing up to a certain delay can be obtained without additional computational complexity by exploiting the state-space structure. We prove that the proposed smoothing strategy strictly improves performance under quite general conditions. Finally, we provide simulations on AR sources, and channels with correlated losses, and show that substantial improvements are possible.","Title: The high-resolution rate-distortion function under the structural similarity index\nYear: 2011\n\nAbstract: We show that the structural similarity (SSIM) index, which is used in image processing to assess the similarity between an image representation and an original reference image, can be formulated as a locally quadratic distortion measure. We, furthermore, show that recent results of Linder and Zamir on the rate-distortion function (RDF) under locally quadratic distortion measures are applicable to this SSIM distortion measure. We finally derive the high-resolution SSIM-RDF and provide a simple method to numerically compute an approximation of the SSIM-RDF of real images.","Title: Distributed remote vector gaussian source coding with covariance distortion constraints\nYear: 2014\n\nAbstract: In this paper, we consider a distributed remote source coding problem, where a sequence of observations of source vectors is available at the encoder. The problem is to specify the optimal rate for encoding the observations subject to a covariance matrix distortion constraint and in the presence of side information at the decoder. For this problem, we derive lower and upper bounds on the rate-distortion function (RDF) for the Gaussian case, which in general do not coincide. We then provide some cases, where the RDF can be derived exactly. We also show that previous results on specific instances of this problem can be generalized using our results. We finally show that if the distortion measure is the mean squared error, or if it is replaced by a certain mutual information constraint, the optimal rate can be derived from our main result.","Title: Sparse Packetized Predictive Control for Networked Control Over Erasure Channels.\nYear: 2013\n\nAbstract: We study feedback control over erasure channels with packet-dropouts. To achieve robustness with respect to packet-dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. To reduce the data size of packets, we propose to adopt sparsity-promoting optimizations, namely, l 1 - l 2 and l 2 -constrained l 0 optimizations, for which efficient algorithms exist. We show how to design the tuning parameters to ensure (practical) stability of the resulting feedback control systems when the number of consecutive packet-dropouts is bounded.","Title: n-Channel Symmetric Multiple-Description Lattice Vector Quantization\nYear: 2005\n\nAbstract: We derive analytical expressions for the central and side quantizers in an n-channel symmetric multiple-description lattice vector quantizer which, under high-resolution assumptions, minimize the expected distortion subject to entropy constraints on the side descriptions for given packet-loss probabilities. The performance of the central quantizer is lattice dependent whereas the performance of the side quantizers is lattice independent. In fact the normalized second moments of the side quantizers are given by that of an L-dimensional sphere. Furthermore, our analytical results reveal a simple way to determine the optimum number of descriptions. We verify theoretical results with numerical experiments and show that with a packet-loss probability of 5%, a gain of 9.1 dB in MSE over state-of-the-art two-description systems can be achieved when quantizing a two-dimensional unit-variance Gaussian source using a total bit budget of 15 bits/dimension and using three descriptions. With 20% packet loss, a similar experiment reveals an MSE reduction of 10.6 dB when using four descriptions.","Title: Bounding the Rate Region of Vector Gaussian Multiple Descriptions with Individual and Central Receivers\nYear: 2010\n\nAbstract: The problem of the rate region of the vector Gaussian multiple description with individual and central quadratic distortion constraints is studied. We have two main contributions. First, a lower bound on the rate region is derived. The bound is obtained by lower-bounding a weighted sum rate for each supporting hyperplane of the rate region. Second, the rate region for the scenario of the scalar Gaussian source is fully characterized by showing that the lower bound is tight. The optimal weighted sum rate for each supporting hyperplane is obtained by solving a single maximization problem. This is contrary to existing results, which require solving a min-max optimization problem.","Title: Multiple-Description Lattice Vector Quantization\nYear: 2007\n\nAbstract: Abstract— In this paper we derive analytical expressions for the central and side quantizers which, under high-resolutions assumptions, minimize the expected distortion of a symmetric multiple-description lattice vector quantization (MD-LVQ) system subject to entropy constraints on the side descriptions for given packet-loss probabilities. We consider a special case of the general n-channel symmetric multiple-description problem,where,only a single parameter controls the redundancy tradeoffs between the central and the side distortions. Previous work on two-channel MD-LVQ showed that the distortions of the side quantizers can be expressed through the normalized second moment,of a sphere. We show here that this is also the case for three-channel MD-LVQ. Furthermore, we conjecture that this is true for the general nchannel MD-LVQ. For given source, target rate and packet-loss probabilities we find the optimal number,of descriptions and construct the MDLVQ system that minimizes the expected distortion. We verify theoretical expressions by numerical simulations and show in a practical setup that significant performance improvements,can be achieved over state-of-the-art two-channel MD-LVQ by using three-channel MD-LVQ. Index Terms— high-rate quantization, lattice quantization,","Title: Predictive power control and multiple-description coding for wireless sensor networks\nYear: 2009\n\nAbstract: We study state estimation via wireless sensor networks over fading channels affected by random packet loss. In the configuration examined, the sensors send their measurements to a single gateway, which decides upon the source coding scheme and the sensor transmitter power levels. The decision process is carried out on-line and adapts to changing channel conditions to achieve an optimal trade-off between estimation quality and sensor energy expenditure. In particular, if some channel conditions are poor, then the gateway commands the corresponding sensors to increase power levels and use multiple-description coding. Simulations based on measured channel data illustrate that the proposed scheme gives excellent results.","Title: Noise-Shaped Predictive Coding for Multiple Descriptions of a Colored Gaussian Source\nYear: 2008\n\nAbstract: It was recently shown that the symmetric multiple-description (MD) quadratic rate-distortion function for memoryless Gaussian sources and two descriptions can be achieved by dithered Delta-Sigma quantization combined with memoryless entropy coding. In this paper,we generalize this result to stationary (colored) Gaussian sources by combining noise shaping and source prediction. We first propose a new representation for the test channel that realizes the MD rate-distortion function of a Gaussian source, both in the white and in the colored source case. We then show that this test channel canbe materialized by embedding two source prediction loops, one for each description, within a common noise shaping loop. While the noise shaping loop controls the tradeoff between the side and the central distortions, the role of prediction (like in differential pulse code modulation) is to extract the source innovations from the reconstruction at each of the side decoders, and thus reduce the coding rate. Finally, we show that this scheme achieves the MD rate-distortion function at all resolutions and all side-to-central distortion ratios, in the limit of high dimensional quantization.","Title: Analysis of LT Codes with Unequal Recovery Time\nYear: 2012\n\nAbstract: In this paper we analyze a specific class of rateless codes, called LT codes with unequal recovery time. These codes provide the option of prioritizing different segments of the transmitted data over other. The result is that segments are decoded in stages during the rateless transmission, where higher prioritized segments are decoded at lower overhead. Our analysis focuses on quantifying the expected amount of received symbols, which are redundant already upon arrival, i.e. all input symbols contained in the received symbols have already been decoded. This analysis gives novel insights into the probabilistic mechanisms of LT codes with unequal recovery time, which has not yet been available in the literature. We show that while these rateless codes successfully provide the unequal recovery time, they do so at a significant price in terms of redundancy in the lower prioritized segments. We propose and analyze a modification where a single intermediate feedback is transmitted, when the first segment is decoded in a code with two segments. Our analysis shows that this modification provides a dramatic improvement on the decoding performance of the lower prioritized segment.","Title: Colored Gaussian Multiple Descriptions: Spectral-Domain Characterization and Time-Domain Design\nYear: 2010\n\nAbstract: It is well known that Shannon's rate-distortion function (RDF) in the colored\nquadratic Gaussian (QG) case, can be parametrized via a single Lagrangian\nvariable (the ``water level'' in the reverse water filling solution). In this\nwork, we show that the symmetric colored QG multiple-description (MD) RDF in\nthe case of two descriptions, can be parametrized via two Lagrangian variables.\nTo establish this result, we use two key ideas. First, we propose a new\nrepresentation for the MD test channel, and show that the minimum mutual\ninformation rate across this channel coincide with the QG MD RDF. Second, we\nuse variational calculus to obtain a spectral domain representation of the test\nchannel's optimal side and central distortion spectra given the source spectral\ndensity and the side and central distortion constraints. The distortion spectra\nare specified via two Lagrangian parameters, which control the trade-off\nbetween the side distortion, the central distortion, and the coding rate.We\nalso show that the symmetric colored QG MD RDF can be achieved by noise-shaped\npredictive coding, dithered quantization, and memoryless entropy coding. In\nparticular, we show that the proposed MD test channel can be materialized by\nembedding two source prediction loops, one for each description, within a\ncommon noise shaping loop whose parameters are explicitly found from the\nspectral-domain characterization. The source prediction loops exploit the\nsource memory, and thus reduce the coding rate. The noise-shaping loop,\ncontrols the trade-off between the side and the central distortions by shaping\nthe quantization noise.","Title: N-Channel Asymmetric Multiple-Description Lattice Vector Quantization\nYear: 2005\n\nAbstract: We present analytical expressions for optimal entropy-constrained multiple-description lattice vector quantizers which, under high-resolutions assumptions, minimize the expected distortion for given packet-loss probabilities. We consider the asymmetric case where packet-loss probabilities and side entropies are allowed to be unequal and find optimal quantizers for any number of descriptions in any dimension. We show that the normalized second moments of the side-quantizers are given by that of an L-dimensional sphere independent of the choice of lattices. Furthermore, we show that the optimal bit-distribution among the descriptions is not unique. In fact, within certain limits, bits can be arbitrarily distributed.","Title: On the Role of Feedback in LT Codes\nYear: 2010\n\nAbstract: This paper concerns application of feedback in LT codes. The considered type\nof feedback is acknowledgments, where information on which symbols have been\ndecoded is given to the transmitter. We identify an important adaptive\nmechanism in standard LT codes, which is crucial to their ability to perform\nwell under any channel conditions. We show how precipitate application of\nacknowledgments can interfere with this adaptive mechanism and lead to\nsignificant performance degradation. Moreover, our analysis reveals that even\nsensible use of acknowledgments has very low potential in standard LT codes.\nMotivated by this, we analyze the impact of acknowledgments on multi layer LT\ncodes, i.e. LT codes with unequal error protection. In this case, feedback\nproves advantageous. We show that by using only a single feedback message, it\nis possible to achieve a noticeable performance improvement compared to\nstandard LT codes.","Title: Sequential remote source coding in wireless acoustic sensor networks.\nYear: 2012\n\nAbstract: In this paper, we consider source coding in wireless acoustic sensor networks (WASNs). A WASN is a network of sensors, where each sensor is equipped with a microphone and thereby forming a distributed microphone array. In addition to a microphone, the sensors communicate via radio channels. Thus, a sensor observes an acoustic noisy measurement in addition to receiving a coded correlated noisy measurement from a neighboring sensor node. Given a set of sensors, the problem is to efficiently encode the noisy observations and/or reencode the received coded noisy observations. Furthermore, one seeks a routing strategy that e. g., minimizes the sum rate subject to some distortion constraints. Towards that end, we define a new source coding concept related to WASNs which we denote sequential remote source coding, and present an achievable rate region in the quadratic Gaussian case.","Title: Sequential Error Concealment for Video/Images by Sparse Linear Prediction\nYear: 2013\n\nAbstract: In this paper, we propose a novel sequential error concealment algorithm for video and images based on sparse linear prediction. Block-based coding schemes in packet loss environments are considered. Images are modelled by means of linear prediction, and missing macroblocks are sequentially reconstructed using the available groups of pixels. The optimal predictor coefficients are computed by applying a missing data regression imputation procedure with a sparsity constraint. Moreover, an efficient procedure for the computation of these coefficients based on an exponential approximation is also proposed. Both techniques provide high-quality reconstructions and outperform the state-of-the-art algorithms both in terms of PSNR and MS-SSIM.","Title: Fundamental Inequalities and Identities Involving Mutual and Directed Informations in Closed-Loop Systems\nYear: 2013\n\nAbstract: We present several novel identities and inequalities relating the mutual information and the directed information in systems with feedback. The internal blocks within such systems are restricted only to be causal mappings, but are allowed to be non-linear, stochastic and time varying. Moreover, the involved signals can be arbitrarily distributed. We bound the directed information between signals inside the feedback loop by the mutual information between signals inside and outside the feedback loop. This fundamental result has an interesting interpretation as a law of conservation of information flow. Building upon it, we derive several novel identities and inequalities, which allow us to prove some existing information inequalities under less restrictive assumptions. Finally, we establish new relationships between nested directed informations inside a feedback loop. This yields a new and general data-processing inequality for systems with feedback.","Title: Design and Analysis of LT Codes with Decreasing Ripple Size\nYear: 2012\n\nAbstract: In this paper we propose a new design of LT codes, which decreases the amount of necessary overhead in comparison to existing designs. The design focuses on a parameter of the LT decoding process called the ripple size. This parameter was also a key element in the design proposed in the original work by Luby. Specifically, Luby argued that an LT code should provide a constant ripple size during de...","Title: Sparsely-Packetized Predictive Control by Orthogonal Matching Pursuit.\nYear: 2013\n\nAbstract: We study packetized predictive control, known to be robust against packet dropouts in networked systems. To obtain sparse packets for rate-limited networks, we design control packets via an l0 optimization, which can be effectively solved by orthogonal matching pursuit. Our formulation ensures asymptotic stability of the control loop in the presence of bounded packet dropouts. 1. Packetized Predictive Control. Let us consider the following discretetime, LTI plant model with a scalar input: x(k + 1) = Ax(k) +Bu(k), k ∈ N0, x(0) = x0, (1.1) where x(k) ∈ R and u(k) ∈ R for k ∈ N0. We assume that (A,B) is reachable. We are interested in a networked control architecture where the controller communicates with the plant actuator through an erasure channel, see Fig. 1.1. This channel introduces bounded packet-dropouts. In packetized predictive control (PPC), as described, e.g., in [4, 2] at each time instant k, the controller uses the state x(k) of the plant (1.1) to calculate and send a control packet of the form u ( x(k) ) , [ u0 ( x(k) ) , u1 ( x(k) ) , . . . , uN−1 ( x(k) )]⊤ ∈ R (1.2) to the plant input node. To achieve robustness against packet dropouts, buffering is used. To be more specific, suppose that at time instant k the data packet u(x(k)) defined in (1.2) is successfully received at the plant input side. Then, this packet is stored in a buffer, overwriting its previous contents. If the next packet, u(x(k+1)), is dropped, then the plant input u(k+1) is set to u1(x(k)), the second element of u(x(k)). The subsequent elements of u(x(k)) are then successively used until some control packet u(x(k+ l)), l ≥ 2, is successfully received, i.e., no dropout occurs. 2. Sparse Control Packet Design for Asymptotic Stability. In the PPC method discussed above, control packets u(x(k)) are transmitted at each time k ∈ N0 through an erasure channel. It is often the case that the bandwidth of the channel is limited, and hence one has to compress control packets to a smaller data size. To achieve an efficient compression of packets, we adopt a technique developed in compressed sensing [1] that considers the sparsity of a signal (or a vector). A sparse vector contains many 0-valued elements and can be highly compressed by only coding ∗This research was supported in part under the MEXT (Japan) Grant-in-Aid for Young Scientists (B) No. 22760317, and also Australian Research Council’s Discovery Projects funding scheme (project number DP0988601). †Graduate School of Informatics, Kyoto University, Kyoto, 606-8501, Japan; e-mail: nagahara@ieee.org ‡School of Electrical Engineering u0026 Computer Science, The University of Newcastle, NSW 2308, Australia; e-mail:dquevedo@ieee.org §Department of Electronic Systems, Aalborg University, Denmark; e-mail: janoe@ieee.org Controller Buffer Plant x(k) u(x(k)) u(k) Fig. 1.1. Networked Control System with PPC its few nonzero components. Based on this notion, in [2] we presented a sparsityinducing l/l optimization for PPC which gives practical stability, i.e., existence of a bounded invariant set. In the present work, we embellish the approach of [2] by showing how to find sparse control packets u(x(k)) ensuring that the networked system with bounded packet dropouts is asymptotically stable. For this, we propose to design the control packets via the following sparsity-promoting optimization: u(x(k)) , argmin u∈RN ∥u∥0 subject to ∥xN |k∥P + N−1 ∑ i=0 ∥xi|k∥Q ≤ x(k)⊤Wx(k), (2.1) where ∥u∥0 is the number of the nonzero elements in u = [u0, u1, . . . , uN−1] and x0|k = x, xi+1|k = Axi|k +Bui, i = 0, 1, . . . , N − 1. (2.2) In (2.2), N is the horizon length, taken here equal to the buffer size. The matrix Q u003e 0 is a design parameter which allows one to shape the response of the plant state components; P u003e 0 and W u003e 0 are chosen such that the feedback system is asymptotically stable, as indicated in Theorem 2.1 below. To state our subsequent results, we introduce the matrices Φ, Υ and Q by Φ , B 0 . . . 0 AB B . . . 0 .. .. . . . .. AN−1B AN−2B . . . B , Υ , A A .. A , Q , blockdiag{Q, . . . , Q } {{ } N−1 , P}. Theorem 2.1 (Asymptotic Stability). Assume that the number of consecutive packet-dropouts is uniformly bounded by N . Suppose the matrices P , Q, and W are chosen by the following procedure: i. Choose Q u003e 0 arbitrarily. ii. Solve the following Riccati equation to obtain P u003e 0: P = A⊤PA−A⊤PB(B⊤PB)−1B⊤PA+Q. (2.3) iii. Compute the constants ρ ∈ [0, 1) and c u003e 0 via ρ , 1− λmin(QP), c , 1− ρ 1− ρ max i λmax { Φi PΦi(Φ ⊤QΦ)−1 } , where Φi is the i-th column of matrix Φ. iv. Choose a matrix E such that 0 u003c E u003c (1− ρ)P/c. v. Set W := P −Q+ E. Then for any choice of the control vector from the feasible set of the optimization (2.1) (which includes the sparsest control packets u(x(k))), the networked control system is asymptotically stable, that is, limk→∞ x(k) = 0. 0 10 20 30 40 50 60 70 80 90 100 10 −30 10 −20 10 −10 10 0 2−norm of the state x(k)","Title: N-channel asymmetric entropy-constrained multiple-description lattice vector quantization\nYear: 2010\n\nAbstract: This paper is about the design and analysis of an index-assignment (IA)-based multiple-description coding scheme for the n-channel asymmetric case. We use entropy constrained lattice vector quantization and restrict attention to simple reconstruction functions, which are given by the inverse IA function when all descriptions are received or otherwise by a weighted average of the received descriptions. We consider smooth sources with finite differential entropy rate and MSE fidelity criterion. As in previous designs, our construction is based on nested lattices which are combined through a single IA function. The results are exact under high-resolution conditions and asymptotically as the nesting ratios of the lattices approach infinity. For any n, the design is asymptotically optimal within the class of IA-based schemes. Moreover, in the case of two descriptions and finite lattice vector dimensions greater than one, the performance is strictly better than that of existing designs. In the case of three descriptions, we show that in the limit of large lattice vector dimensions, points on the inner bound of Pradhan et al. can be achieved. Furthermore, for three descriptions and finite lattice vector dimensions, we show that the IA-based approach yields, in the symmetric case, a smaller rate loss than the recently proposed source-splitting approach.","Title: Iterated Smoothing For Accelerated Gradient Convex Minimization In Signal Processing\nYear: 2010\n\nAbstract: In this paper, we consider the problem of minimizing a non-smooth convex problem using first-order methods. The number of iterations required to guarantee a certain accuracy for such problems is often excessive and several methods, e.g., restart methods, have been proposed to speed-up the convergence. In the restart method a smoothness parameter is adjusted such that smoother approximations of the original non-smooth problem are solved in a sequence before the original, and the previous estimate is used as the starting point each time. Instead of adjusting the smoothness parameter after each restart, we propose a method where we modify the smoothness parameter in each iteration. We prove convergence and provide simulation examples for two typical signal processing applications, namely total variation denoising and l(1)-norm minimization. The simulations demonstrate that the proposed method require fewer iterations and show lower complexity compared to the restart method.","Title: High-Rate Analysis of Symmetric L-Channel Multiple Description Coding.\nYear: 2011\n\nAbstract: This paper studies the tight rate-distortion bound for L-channel symmetric multiple-description coding of a scalar Gaussian source with two levels of receivers. Each of the first-level receivers obtains κ of the L descriptions (κ <; L). The second-level receiver obtains all L descriptions. We find that if the central distortion (corresponding to the second-level receiver) is much smaller than the ...","Title: Practical design of delta-sigma multiple description audio coding.\nYear: 2014\n\nAbstract: It was recently shown that delta-sigma quantization (DSQ) can be used for optimal multiple description (MD) coding of Gaussian sources. The DSQ scheme combined oversampling, prediction, and noise-shaping in order to trade off side distortion for central distortion in MD coding. It was shown that asymptotically in the dimensions of the resampling, prediction, and noise-shaping filters as well as asymptotically in the quantizer dimensions, all rate-distortion points on the symmetric quadratic Gaussian MD rate-distortion function could be achieved. In this work, we show that this somewhat theoretical framework is suitable for practical low-delay MD audio coding. In particular, we design a practical MD audio coder with two descriptions and provide simulations on real audio data. The simulations demonstrate that even when using low-dimensional noise-shaping, prediction, and resampling filters, it is possible to obtain good quality audio in the presence of packet losses. Simulations on real audio reveal that, contrary to existing designs, it is straightforward to obtain a large number of trade-off points between side distortion and central distortion, which makes the proposed coder suitable for a wide range of applications.","Title: Improved Upper Bounds to the Causal Quadratic Rate-Distortion Function for Gaussian Stationary Sources\nYear: 2012\n\nAbstract: We improve the existing achievable rate regions for causal and for zero-delay source coding of stationary Gaussian sources under an average mean squared error distortion measure. To begin with, we find a closed-form expression for the information-theoretic causal rate-distortion function (RDF) under such distortion measure, denoted by $R_{c}^{it}(D)$ , for first-order Gauss–Markov processes. $R_{c}^{it}(D)$ is a lower bound to the optimal performance theoretically attainable (OPTA) by any causal source code, namely $R_{c}^{op}(D)$ . We show that, for Gaussian sources, the latter can also be upper bounded as $R_{c}^{op}(D) \\\\leq R_{c}^{it}(D) + 0.5\\\\log _{2}(2\\\\pi {\\\\rm e}^{})$ bits/sample. In order to analyze $R_{c}^{it}(D)$ for arbitrary zero-mean Gaussian stationary sources, we introduce $\\\\overline {R_{c}^{it}}(D)$ , the information-theoretic causal RDF when the reconstruction error is jointly stationary with the source. Based upon $\\\\overline {R_{c}^{it}}(D)$, we derive three closed-form upper bounds to the additive rate loss defined as $\\\\overline {{R}_{c}^{it}}(D) - R(D)$ , where $R(D)$ denotes Shannon's RDF. Two of these bounds are strictly smaller than 0.5 bits/sample at all rates. These bounds differ from one another in their tightness and ease of evaluation; the tighter the bound, the more involved its evaluation. We then show that, for any source spectral density and any positive distortion $D\\\\leq \\\\sigma _{x}^{2}$, $\\\\overline {R_{c}^{it}}(D)$ can be realized by an additive white Gaussian noise channel surrounded by a unique set of causal pre-, post-, and feedback filters. We show that finding such filters constitutes a convex optimization problem. In order to solve the latter, we propose an iterative optimization procedure that yields the optimal filters and is guaranteed to converge to $\\\\overline {R_{c}^{it}}(D)$ . Finally, by establishing a connection to feedback quantization, we design a causal and a zero-delay coding scheme which, for Gaussian sources, achieves an operational rate lower than $\\\\overline {R_{c}^{it}}(D) + 0.254$ and $\\\\overline {R_{c}^{it}}(D) + 0.754$ bits/sample, respectively. This implies that the OPTA among all zero-delay source codes, denoted by $R_{zd}^{op}(D)$, is upper bounded as $R_{zd}^{op}(D)< \\\\overline {R_{c}^{it}}(D) + 1.254 < R(D) + 1.754$ bits/sample.","Title: Audio coding in wireless acoustic sensor networks.\nYear: 2015\n\nAbstract: In this paper, we consider the problem of source coding for a wireless acoustic sensor network where each node in the network makes its own noisy measurement of the sound field, and communicates with other nodes in the network by sending and receiving encoded versions of the measurements. To make use of the correlation between the sources available at the nodes, we consider the possibility of combining the measurement and the received messages into one single message at each node instead of forwarding the received messages and separate encoding of the measurement. Moreover, to exploit the correlation between the messages received by a node and the node׳s measurement of the source, we propose to use the measurement as side information and thereby form a distributed source coding (DSC) problem. Assuming that the sources are Gaussian, we then derive the rate-distortion function (RDF) for the resulting remote DSC problem under covariance matrix distortion constraints. We further show that for this problem, the Gaussian source is the worst to code. Thus, the Gaussian RDF provides an upper bound to other sources such as audio signals. We then turn our attention to audio signals. We consider an acoustical model based on the room impulse response (RIR) and provide simulation results for the rate-distortion performance in a practical setup where a set of microphones record the sound in a standard listening room. Since our reconstruction scheme and distortion measure are defined over the direct sound source, coding and dereverberation are performed in a joint manner.","Title: A Characterization of the Minimal Average Data Rate that Guarantees a Given Closed-Loop Performance Level.\nYear: 2014\n\nAbstract: This paper studies networked control systems closed over noiseless digital channels. We focus on noisy linear time-invariant (LTI) plants with stationary Gaussian disturbances, Gaussian initial state, scalar-valued control inputs and sensor outputs. For this set-up, we show that the absolute minimal directed information rate that allows one to achieve a prescribed level of performance (not necessarily stationary), over all combinations of encoder-controller-decoder, is achieved when the decoder output is jointly Gaussian with the other signals in the system. This directed information rate lower bounds the achievable operational data rates. When restricting our attention to encoder-controller-decoders which make the random processes in the loop (strongly) asymptotically wide-sense stationary, this bound can be expressed in terms of their asymptotic power spectral densities. Then we show that the directed information rate and stationary performance of any such scheme can be achieved when the concatenated encoder, channel, controller and decoder behave as an AWGN channel with LTI filters. We also present a simple coding scheme that allows one to achieve (operational) average data rates that are at most (approximately) 1.254 bits away from the derived lower bound, while satisfying the performance constraint. A numerical example is presented to illustrate our findings.","Title: Distributed Remote Vector Gaussian Source Coding for Wireless Acoustic Sensor Networks\nYear: 2014\n\nAbstract: In this paper, we consider the problem of remote vector Gaussian source coding for a wireless acoustic sensor network. Each node receives messages from multiple nodes in the network and decodes these messages using its own measurement of the sound field as side information. The node's measurement and the estimates of the source resulting from decoding the received messages are then jointly encoded and transmitted to a neighbouring node in the network. We show that for this distributed source coding scenario, one can encode a so-called conditional sufficient statistic of the sources instead of jointly encoding multiple sources. We focus on the case where node measurements are in form of noisy linearly mixed combinations of the sources and the acoustic channel mixing matrices are invertible. For this problem, we derive the rate-distortion function for vector Gaussian sources and under covariance distortion constraints.","Title: Modelling temporal variations by polynomial regression for classification of radar tracks\nYear: 2014\n\nAbstract: The sampling rate of a radar is often too low to reliably capture the acceleration of moving targets such as birds. Moreover, the sampling rate depends upon the target's acceleration and heading and will therefore generally be time varying. When classifying radar tracks using temporal features, too low or highly varying sampling rates deteriorates the classifier's performance. In this work, we propose to model the temporal variations of the target's speed by low-order polynomial regression. Using the polynomial we obtain the conditional statistics of the targets speed at some future time given its speed at the current time. When used in a classifier based on Gaussian mixture models and with real radar data, it is shown that the inclusions of conditional statistics describing the targets temporal variations, leads to a substantial improvement in the overall classification performance.","Title: Perceptual Audio Coding Using N-Channel Lattice Vector Quantization\nYear: 2006\n\nAbstract: We consider the problem of reliable distribution of audio over packet-switched networks. We make use of multiple-description coding combined with transform coding in order to obtain robustness towards packet losses. Previous approaches to this problem were restricted to the case of only two descriptions. In this work we use n-channel multiple-description lattice vector quantizers (MD-LVQs), which allow for the possibility of using more than two descriptions. For a given packet-loss probability we find the number of descriptions and the bit allocation between transform coefficients which minimizes a perceptual distortion measure subject to an entropy constraint. The optimal quantizers are presented in closed form, thus avoiding any iterative quantizer design procedures. The theoretical results are verified with numerical computer simulations using audio signals and it is shown that in environments with excessive packet losses it is advantageous to use more than two descriptions. We verify in subjective listening tests that using more than two descriptions lead to signals of perceptually higher quality","Title: Multiple-Description Coding by Dithered Delta–Sigma Quantization\nYear: 2007\n\nAbstract: We address the connection between the multiple-description (MD) problem and Delta-Sigma quanti- zation. The inherent redundancy due to oversampling in Delta-Sigma quantization, and the simple linear- additive noise model resulting from dithered lattice quant ization, allow us to construct a symmetric MD coding scheme. We show that the use of a noise shaping filter ma kes it possible to trade off central distortion for side distortion. Asymptotically as the dime nsion of the lattice vector quantizer and order of the noise shaping filter approach infinity, the entropy rat e of the dithered Delta-Sigma quantization scheme approaches the symmetric two-channel MD rate-distortion function for a memoryless Gaussian source and MSE fidelity criterion, at any side-to-central di stortion ratio and any resolution. In the optimal scheme, the infinite-order noise shaping filter must be minim um phase and have a piece-wise flat power spectrum with a single jump discontinuity. We further show that the optimal noise-shaping filter of any order can be found by solving a set of Yule-Walker equations, and we present an exact rate-distortion analysis for any filter order, lattice vector quantizer dime nsion and bit rate. An important advantage of the proposed design is that it is symmetric in rate by constru ction, and there is therefore no need for source splitting.","Title: Low delay moving-horizon multiple-description audio coding forwireless hearing aids\nYear: 2009\n\nAbstract: In this work, we construct a novel scheme for efficient perceptual coding of audio for robust communication between encoders and wireless hearing aids. To limit the physical size of the hearing aids and to reduce power consumption and thereby increase the lifetime expectancy of the batteries, the hearing aids are constrained to be of low complexity. We therefore provide an asymmetric strategy where most of the computational load is placed at the encoding side. We make use of multiple-description coding. This combats possible erasures on the wireless link between the encoder and the hearing aids without introducing significant delay. Furthermore, we employ psychoacoustically optimized noise-shaping quantizers based on the moving-horizon principle, which exploits a finite prediction horizon.","Title: Sequential Error Concealment for Video/Images by Weighted Template Matching\nYear: 2012\n\nAbstract: In this paper we propose a novel spatial error concealment algorithm for video and images based on convex optimization. Block-based coding schemes in packet loss environment are considered. Missing macro blocks are sequentially reconstructed by filling them with a weighted set of templates extracted from the available neighbourhood. Moreover, a fast approximation of the optimization method is proposed. The technique produces high quality reconstructions that outperforms the state-of-the-art algorithms both in terms of PSNR and MS-SSIM.","Title: Quantized predictive control over erasure channels\nYear: 2009\n\nAbstract: We study a control architecture for linear time-invariant plants which are affected by random disturbances. The distinguishing aspect of the situation at hand is that an unreliable data-rate limited network is placed between controller and the plant input. To achieve robustness with respect to i.i.d. dropouts, the controller transmits data packets containing quantized plant input predictions. These minimize a finite horizon cost function and are provided by an appropriate optimal entropy coded dithered lattice vector quantizer. Within this context, we derive an equivalent noise-shaping model of the closed loop system. This model is employed for the design and analysis of the vector quantizer used by the controller.","Title: Packetized predictive control for rate-limited networks via sparse representation\nYear: 2013\n\nAbstract: We study a networked control architecture for linear time-invariant plants in which an unreliable data-rate limited network is placed between the controller and the plant input. The distinguishing aspect of the situation at hand is that an unreliable data-rate limited network is placed between controller and the plant input. To achieve robustness with respect to dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. In our formulation, we design sparse packets for rate-limited networks, by adopting an an ℓ0 optimization, which can be effectively solved by an orthogonal matching pursuit method. Our formulation ensures asymptotic stability of the control loop in the presence of bounded packet dropouts. Simulation results indicate that the proposed controller provides sparse control packets, thereby giving bit-rate reductions for the case of memoryless scalar coding schemes when compared to the use of, more common, quadratic cost functions, as in linear quadratic (LQ) control.","Title: Independent source coding for control over noiseless channels\nYear: 2010\n\nAbstract: By focusing on a class of source coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source coding scheme has to be deployed in the feedback path. We give a closed form expression for the minimal average data-rate required to achieve a given performance level, and also study the interplay between stability and average data-rates for the considered architecture.","Title: Multiple Description Coding for Closed Loop Systems over Erasure Channels\nYear: 2013\n\nAbstract: In this paper, we consider robust source coding in closed-loop systems. In particular, we consider a (possibly) unstable LTI system, which is to be stabilized via a network. The network has random delays and erasures on the data-rate limited (digital) forward channel between the encoder (controller) and the decoder (plant). The feedback channel from the decoder to the encoder is assumed noiseless. Since the forward channel is digital, we need to employ quantization. We combine two techniques to enhance the reliability of the system. First, in order to guarantee that the system remains stable during packet dropouts and delays, we transmit quantized control vectors containing current control values for the decoder as well as future predicted control values. Second, we utilize multiple description coding based on forward error correction codes to further aid in the robustness towards packet erasures. In particular, we transmit M redundant packets, which are constructed such that when receiving any J packets, the current control signal as well as J-1 future control signals can be reliably reconstructed at the decoder. We prove stability subject to quantization constraints, random dropouts, and delays by showing that the system can be cast as a Markov jump linear system.","Title: Sampling versus random binning for multiple descriptions of a bandlimited source\nYear: 2013\n\nAbstract: Random binning is an efficient, yet complex, coding technique for the symmetric L-description source coding problem. We propose an alternative approach, that uses the quantized samples of a bandlimited source as “descriptions”. By the Nyquist condition, the source can be reconstructed if enough samples are received. We examine a coding scheme that combines sampling and noise-shaped quantization for a scenario in which only K <;L descriptions or all L descriptions are received. Some of the received K-sets of descriptions correspond to uniform sampling while others to non-uniform sampling. This scheme achieves the optimum rate-distortion performance for uniform-sampling K-sets, but suffers noise amplification for nonuniform-sampling K-sets. We then show that by increasing the sampling rate and adding a random-binning stage, the optimal operation point is achieved for any K-set.","Title: An Achievable Data-Rate Region Subject to a Stationary Performance Constraint for LTI Plants\nYear: 2011\n\nAbstract: This note studies the performance of control systems subject to average data-rate limits. We focus on a situation where a noisy LTI system has been designed assuming transparent feedback and, due to implementation constraints, a source coding scheme (with unity signal transfer function) has to be deployed in the feedback path. For this situation and by focusing on a specific source coding scheme, we give a closed-form upper bound on the minimal average data-rate that allows one to attain a given performance level. Instrumental to our main result is the explicit solution of a related signal-to-noise ratio minimization problem, subject to a closed loop performance constraint.","Title: Packetized Predictive Control of Stochastic Systems Over Bit-Rate Limited Channels With Packet Loss\nYear: 2011\n\nAbstract: We study a control architecture for linear time-invariant plants with random disturbances and where a network is placed between the controller output and the plant input. The network imposes a constraint on the expected bit-rate and is affected by random independent and identically distributed (i.i.d.) dropouts. Dropout-rates and acknowledgments of receipt are not available at the controller side. To achieve robustness with respect to i.i.d. dropouts, the controller transmits data packets containing quantized plant input predictions. These are provided by an appropriate optimal entropy coded dithered lattice vector quantizer. Within this context, we derive stochastic stability results and provide a noise-shaping model of the closed loop system. This model is employed for performance analysis by using rate-distortion theory.","Title: Predictive power control for dynamic state estimation over wireless sensor networks with relays\nYear: 2010\n\nAbstract: We present a predictive power controller for state estimation of a stationary ARMA process over a wireless sensor network (WSN), consisting of sensor nodes, relays, and a single gateway (GW). The state estimate is formed centrally at the GW by using packets received from sensors and relays. The latter perform network coding of sensor measurements. Communication from sensors and relays to the GW is over a fading channel. Packet loss probabilities depend upon the time-varying channel gains and the transmission powers used. To achieve an optimal trade-off between state estimation quality and energy expenditure, in our approach the GW decides upon the in general time-varying transmission powers of sensors and relays. This decision process is carried out on-line and adapts to changing channel conditions by using elements of stochastic model predictive control. Simulations on measured channel data illustrate the performance achieved by the proposed controller.","Title: Multiple descriptions using sparse decompositions\nYear: 2010\n\nAbstract: In this paper, we consider the design of multiple descriptions (MDs) using sparse decompositions. In a description erasure channel only a subset of the transmitted descriptions is received. The MD problem concerns the design of the descriptions such that they individually approximate the source and furthermore are able to refine each other. In this paper, we form descriptions using convex optimization with l1-norm minimization and Euclidean distortion constraints on the reconstructions and show that with this method we can obtain non-trivial descriptions. We give an algorithm based on recently developed first-order method to the proposed convex problem such that we can solve large-scale instances for image sequences.","Title: Rate-distortion in closed-loop LTI systems\nYear: 2013\n\nAbstract: We consider a networked LTI system subject to an average data-rate constraint in the feedback path. We provide upper bounds to the minimal source coding rate required to achieve mean square stability and a desired level of performance. In the quadratic Gaussian case, an almost complete rate-distortion characterization is presented.","Title: Shaped Gaussian Dictionaries for Quantized Networked Control Systems With Correlated Dropouts\nYear: 2016\n\nAbstract: This paper studies fixed rate vector quantisation for noisy networked control systems (NCSs) with correlated packet dropouts. In particular, a discrete-time linear time invariant system is to be controlled over an error-prone digital channel. The controller uses (quantized) packetized predictive control to reduce the impact of packet losses. The proposed vector quantizer is based on sparse regression codes (SPARC), which have recently been shown to be efficient in open-loop systems when coding white Gaussian sources. The dictionaries in existing design of SPARCs consist of independent and identically distributed (i.i.d.) Gaussian entries. However, we show that a significant gain can be achieved by using Gaussian dictionaries that are shaped according to the second-order statistics of the NCS in question. Furthermore, to avoid training of the dictionaries, we provide closed-form expressions for the required second-order statistics in the absence of quantization.","Title: Reconstruction Algorithms in Undersampled AFM Imaging.\nYear: 2016\n\nAbstract: This paper provides a study of spatial undersampling in atomic force microscopy (AFM) imaging followed by different image reconstruction techniques based on sparse approximation as well as interpolation. The main reasons for using undersampling is that it reduces the path length and thereby the scanning time as well as the amount of interaction between the AFM probe and the specimen. It can easily...","Title: Online estimation of wind turbine blade deflection with UWB signals\nYear: 2015\n\nAbstract: In this paper we use ultra-wideband (UWB) signals for the localization of blade tips on wind turbines. Our approach is to acquire two separate distances to each tip via time-delay estimation, and each tip is then localized by triangulation. We derive an approximate maximiun a posteriori (MAP) delay estimator exploiting i) contextual prior information and ii) direct-path approximation. The resulting deflection estimation algorithm is computationally feasible for online usage. Simulation studies are conducted to assess the overall triangulation uncertainty and it is observed that negative correlation between the two distance estimates is detrimental for the tip localization accuracy. Measurement data acquired in an anechoic chamber is used to confirm that the UWB-hardware complies with the desired/relevant ranging accuracy. Finally, measurement data obtained from a static test bench is used to demonstrate that the approximate MAP-based localization algorithm is able to outperform standard methods.","Title: Predicting reconstruction quality within compressive sensing for atomic force microscopy\nYear: 2015\n\nAbstract: With compressive sensing, the obtainable reconstruction quality depends on the original signal, the reconstruction algorithm, the measurement matrix, and the dictionary matrix. The present paper is concerned with establishing performance indicators and using these to predict reconstruction quality in atomic force microscopy applications. For this purpose, we consider the well-known quantities of coherence and mutual coherence. Furthermore, we propose a new performance indicator derived from coherence in order to better model the average reconstruction quality. Through extensive simulations, affine models using the performance indicators are evaluated in terms of modified coefficients of determination. The results show that the proposed performance indicator yields a better model than both coherence and mutual coherence do. In conclusion, the proposed performance indicator can be used to predict reconstruction quality for the given application, and the affine prediction model can be improved by including coherence and mutual coherence.","Title: Multiple descriptions for packetized predictive control.\nYear: 2016\n\nAbstract: In this paper, we propose to use multiple descriptions (MDs) to achieve a high degree of robustness towards random packet delays and erasures in networked control systems. In particular, we consider the scenario, where a data-rate limited channel is located between the controller and the plant input. This forward channel also introduces random delays and dropouts. The feedback channel from the plant output to the controller is assumed noiseless. We show how to design MDs for packetized predicted control (PPC) in order to enhance the robustness. In the proposed scheme, a quantized control vector with future tentative control signals is transmitted to the plant at each discrete time instant. This control vector is then transformed into M redundant descriptions (packets) such that when receiving any 1≤J≤M packets, the current control signal as well as J−1 future control signals can be reliably reconstructed at the plant side. For the particular case of LTI plant models and i.i.d. channels, we show that the overall system forms a Markov jump linear system. We provide conditions for mean square stability and derive upper bounds on the operational bit rate of the quantizer to guarantee a desired performance level. Simulations reveal that a significant gain over conventional PPC can be achieved when combining PPC with suitably designed MDs.","Title: Discrete-time hands-off control by sparse optimization.\nYear: 2016\n\nAbstract: Maximum hands-off control is a control mechanism that maximizes the length of the time duration on which the control is exactly zero. Such a control is important for energy-aware control applications, since it can stop actuators for a long duration and hence the control system needs much less fuel or electric power. In this article, we formulate the maximum hands-off control for linear discrete-time plants by sparse optimization based on the l 1 norm. For this optimization problem, we derive an efficient algorithm based on the alternating direction method of multipliers (ADMM). We also give a model predictive control formulation, which leads to a robust control system based on a state feedback mechanism. Simulation results are included to illustrate the effectiveness of the proposed control method.","Title: A recursive kinematic random forest and alpha beta filter classifier for 2D radar tracks.\nYear: 2016\n\nAbstract: In this work, we show that by using a recursive random forest together with an alpha beta filter classifier, it is possible to classify radar tracks from the tracks’ kinematic data. The kinematic data is from a 2D scanning radar without Doppler or height information. We use random forest as this classifier implicitly handles the uncertainty in the position measurements. As stationary targets can have an apparently high speed because of the measurement uncertainty, we use an alpha beta filter classifier to classify stationary targets from moving targets. We show an overall classification rate from simulated data at 82.6 % and from real-world data at 79.7 %. Additional to the confusion matrix, we also show recordings of real-world data.","Title: Delay Minimization in Real-time Communications with Joint Buffering and Coding.\nYear: 2017\n\nAbstract: We present a closed-form expression for the minimal delay that is achievable in a setting that combines a buffer and an erasure code, used to mitigate the packet delay variance. The erasure code is modeled according to the recent information-theoretic results on finite block length codes. Evaluations reveal that accurate knowledge of the network parameters is essential for optimal operation. Moreover, it is shown that, when the network packet delay variance is large, the buffer delay becomes negligible. Therefore, in this case, the delay budget should be spent mainly on the erasure code.","Title: Source Coding in Networks With Covariance Distortion Constraints.\nYear: 2016\n\nAbstract: We consider a source coding problem with a network scenario in mind, and formulate it as a remote vector Gaussian Wyner-Ziv problem under covariance matrix distortions. We define a notion of minimum for two positive-definite matrices based on which we derive an explicit formula for the rate-distortion function. We then study the special cases and applications of this result. We show that two well-...","Title: Interplay Between Transmission Delay, Average Data Rate, And Performance In Output Feedback Control Over Digital Communication Channels\nYear: 2017\n\nAbstract: The performance of a noisy linear time-invariant (LTI) plant, controlled over a noiseless digital channel with transmission delay, is investigated in this paper. The rate limited channel connects the single measurement output of the plant to its single control input through a causal, but otherwise arbitrary, coder-controller pair. An information theoretic approach is utilized to analyze the minimal average data rate required to attain the quadratic performance when the channel imposes a known constant delay on the transmitted data. This infimum average data rate is shown to be lower bounded by minimizing the directed information rate across a set of LTI filters and an additive white Gaussian noise (AWGN) channel. It is demonstrated that the presence of time delay in the channel increases the data rate needed to achieve a certain level of performance. The applicability of the results is verified through a numerical example.","Title: Zero-Delay Rate Distortion via Filtering for Unstable Vector Gaussian Sources.\nYear: 2017\n\nAbstract: In this work, we deal with zero-delay source coding of an unstable vector Gaussian Auto-Regressive (AR) source under average mean square error fidelity criterion. To begin with, we consider zero-delay coding of a vector Gaussian AR(1) source modeled in state space form. It turns out to be convenient to use an asymptotically stationary time-domain scheme with feedback, which was recently proposed in [1] in the context of filtering theory applications via the Information Nonanticipative Rate Distortion Function (INRDF). In this scheme, the feedback path comprises a Kalman filter, which produces an estimate of the source. Our idea is then to encode the vector innovations due to Kalman filtering via lattice quantization with subtractive dither and memoryless entropy coding. We show that the resulting system is stable and furthermore provide new bounds to the zero-delay RDF. We then generalize our results to vector Gaussian AR sources of any order. With this, we are able to establish a time-domain approach with feedback, which by use of a single filter gets very close to the zero-delay RDF for vector Gaussian AR sources of any order. Interestingly, for infinite dimensional vector sources, the INRDF coincides with the Optimal Performance Theoretically Attainable (OPTA) by zero-delay codes.","Title: On Perceptual Audio Compression with Side Information at the Decoder\nYear: 2016\n\nAbstract: Due to the distributed structure of many modern audio transmission setups, it is likely to have an observation at the receiver which is correlated with the desired source at the transmitter. This observation could be used as side information to reduce the transmission rate using distributed source coding. How to integrate distributed source coding into the perceptual audio compression procedure is thus a fundamental question. In this paper, we take a completely analytical approach to this problem, in particular to the rate-distortion trade-off and the corresponding coding schemes. We then interpret the results from an audio coding perspective. The main result is that, to upgrade a regular perceptual audio coder to a distributed coder, one needs to revise the perceptual masking curve. The revised masking curve models the availability of the side information as an extra masking effect, yielding lower rates. Interestingly, this means that at least conceptually, the distributed coding scenario could be integrated into the audio coder with minor changes, and without destructing the original coder.","Title: An Asymmetric Difference Multiple Description Gaussian Noise Channel\nYear: 2017\n\nAbstract: Ozarow's test channel for the quadratic Gaussian (QG) multiple description (MD) problem consists of two correlated AWGN channels. It is known that simply replacing the AWGN channels by quantizers with equivalent statistical properties as the channels, will generally not lead to a rate-distortion optimal realization of the MD rate-distortion function. We have previously proposed a symmetric two-channel model for the QG MD problem for the case, where the two noise terms have equal variances. We show in this paper, that by replacing the AWGN channels of this model by quantizers that are statistical equivalent to the channels, will under high-resolution assumption be rate-distortion optimal. We furthermore extend this symmetric two-channel model to the asymmetric case, and provide a simple suboptimal implementation of the channel based on scalar quantizers. Simulations are provided to show the performance of the proposed implementation.","Title: Detection of spoken words in noise: Comparison of human performance to maximum likelihood detection\nYear: 2016\n\nAbstract: In this work, we are interested in assessing the optimality of the human auditory system, when the input stimuli is natural speech that is affected by additive noise. In order to do this, we consider the DANTALE II listening test paradigm of Wagener et al., which has been used to evaluate the intelligibility of noisy speech by exposing human listeners to a selection of constructed noisy sentences. Inspired by this test, we propose a simple model for the communication and classification of noisy speech that takes place in the test. We then identify a number of key properties that the test subjects satisfy, and combine these with our proposed model in order to derive optimal classifiers in the sense of maximum a posteriori estimation. We finally compare the performance of the classifiers to that of humans on the same noisy test sentences. The results reveal that at low SNRs, the human performance is inferior to that of the optimal classifiers. We conclude that in this special task, the human auditory system is not optimal.","Title: Superregular Lower Triangular Toeplitz Matrices for Low Delay Wireless Streaming.\nYear: 2017\n\nAbstract: A matrix is termed superregular if all of its possible submatrices are non-singular. Superregular lower triangular Toeplitz matrices are useful for MDS convolutional codes and (sequential) network codes. In this paper, we present the explicit matrix constructions for superregular lower triangular Toeplitz matrices in GF(2p)k×k, k ≤ 5. For k > 5 we provide a greedy algorithm, which (over sufficient...","Title: Humans Do Not Maximize The Probability Of Correct Decision When Recognizing Dantale Words In Noise\nYear: 2017\n\nAbstract: Inspired by the DANTALE II listening test paradigm, which is used for determining the intelligibility of noisy speech, we assess the hypothesis that humans maximize the probability of correct decision when recognizing words contaminated by additive Gaussian. speech-shaped noise. We first propose a statistical Gaussian communication and classification scenario, where word models are built from short term spectra of human speech, and optimal classifiers in the sense of maximum a posteriori estimation are derived. Then, we perform a listening test, where the participants are instructed to make their best guess of words contaminated with speech-shaped Gaussian noise. Comparing the human's performance to that of the optimal classifier reveals that at high SNR. humans perform comparable to the optimal classifier. However, at low SNR, the human performance is inferior to that of the optimal classifier. This shows that, at least in this specialized task, humans are generally not able to maximize the probability of correct decision, when recognizing words.","Title: Achievable Performance Of Zero-Delay Variable-Rate Coding In Rate-Constrained Networked Control Systems With Channel Delay\nYear: 2017\n\nAbstract: This paper presents an upper bound on the minimum data rate required to achieve a prescribed closed-loop performance level in networked control systems (NCSs). The considered feedback loop includes a linear time-invariant (LTI) plant with single measurement output and single control input. Moreover, in this NCS, a causal but otherwise unconstrained feedback system carries out zero-delay variable-rate coding, and control. Between the encoder and decoder, data is exchanged over a rate-limited noiseless digital channel with a known constant time delay. Here we propose a linear source-coding scheme that with the use of entropy-coded dithered quantizers (ECDQs), attains each quadratic performance level with a rate that exceeds the lower bound in [1] by at most (approximately) 1.254 bits per sample. The upper bound obtained by ECDQ is demonstrated, via simulations, to be an increasing function of the channel time delay at any given performance. In other words, attaining a specific performance level necessitates achieving a higher data rate when the channel time delay grows. The theoretical framework is demonstrated via an illustrative example.","Title: Stationarity in the Realizations of the Causal Rate-Distortion Function for One-Sided Stationary Sources.\nYear: 2018\n\nAbstract: This paper derives novel results on the characterization of the the causal information rate-distortion function (IRDF) $R_{c}^{it}(D)$ for arbitrarily-distributed one-sided stationary $kappa$-th order Markov source x(1),x(2),.... It is first shown that Gorbunov and Pinskeru0027s results on the stationarity of the realizations to the causal IRDF (stated for two-sided stationary sources) do not apply to the commonly used family of asymptotic average single-letter (AASL) distortion criteria. Moreover, we show that, in general, a reconstruction sequence cannot be both jointly stationary with a one-sided stationary source sequence and causally related to it. This implies that, in general, the causal IRDF for one-sided stationary sources cannot be realized by a stationary distribution. However, we prove that for an arbitrarily distributed one-sided stationary source and a large class of distortion criteria (including AASL), the search for $R_{c}^{it}(D)$ can be restricted to distributions which yield the output sequence y(1), y(2),... jointly stationary with the source after $kappa$ samples. Finally, we improve the definition of the stationary causal IRDF $overline{R}_{c}^{it}(D)$ previously introduced by Derpich and {O}stergaard for two-sided Markovian stationary sources and show that $overline{R}_{c}^{it}(D)$ for a two-sided source ...,x(-1),x(0),x(1),... equals $R_{c}^{it}(D)$ for the associated one-sided source x(1), x(2),.... This implies that, for the Gaussian quadratic case, the practical zero-delay encoder-decoder pairs proposed by Derpich and {O}stergaard for approaching $R_{c}^{it}(D)$ achieve an operational data rate which exceeds $R_{c}^{it}(D)$ by less than $1+0.5 log_2(2 pi e /12) simeq 1.254$ bits per sample.","Title: Estimation of the second heart sound split using windowed sinusoidal models.\nYear: 2018\n\nAbstract: •A2 and P2 are modeled as windowed sinusoids and their sum forms the S2 signal.•S2 split is estimated by cross-correlating the measured S2 and the modeled A2/P2.•RMSE of 7.6 ms for synthetic S2 signals with S2 split swept from −70 to 70 ms.•Results from 146 PCG recordings show an average S2 split of 29.6 ms.","Title: Fixed-Rate Zero-Delay Source Coding for Stationary Vector-Valued Gauss-Markov Sources\nYear: 2018\n\nAbstract: We consider a fixed-rate zero-delay source coding problem where a stationary vector-valued Gauss-Markov source is compressed subject to an average mean-squared error (MSE) distortion constraint. We address the problem by considering the Gaussian nonanticipative rate distortion function (NRDF) which is a lower bound to the zero-delay Gaussian RDF. Then, we use its corresponding optimal “test-channel” to characterize the stationary Gaussian NRDF and evaluate the corresponding information rates. We show that the Gaussian NRDF can be achieved by p-parallel fixed-rate scalar uniform quantizers of finite support with dithering signal up to a multiplicative distortion factor and a constant rate penalty. We demonstrate our framework with a numerical example.","Title: On Superregular Matrices and Convolutional Codes with Finite Decoder Memory\nYear: 2018\n\nAbstract: In this paper, we present explicit code constructions for a family of (n,k,δ) convolutional codes with optimum distance profiles. The family of convolutional codes is obtained from sets of jointly superregular matrices. For the case of finite decoder memory, we evaluate the performance of the constructed codes in terms of both symbol loss probability and symbol delay. We then present a combinatorial method to calculate the exact symbol loss probability and symbol delay for each symbol individually. We compare the symbol loss probability for two specific systematic convolutional codes for the cases where the sink has infinite or finite memory. Finally, we compare the performance of our convolutional codes with optimum distance profile and random based convolutional codes.","Title: Sequential Use of Block Codes and Convolutional Codes in a Real-Time Multi-Hop Network\nYear: 2018\n\nAbstract: Real-time streaming of audio and video have tight constraints on the delay allowed at each step in the distribution chain. In this paper, we focus on the transport layer. That is, we investigate the effect of imposing a maximum allowable delay on the symbol loss probability for a set of rate 1/2 erasure correcting codes. We define the effective symbol loss probability to be the probability that a symbol is received too late or not at all, given some maximum allowable delay. We consider networks where the source and sink communicate via a relaying node, and that this intermediate node performs recoding. The erasure correcting code used between the source and relay need not be the same as the erasure correcting code used between the relay and sink. Moreover, on the first link, we use both a block code and on the second link we use a convolutional code. In order to do a fair comparison, we also include the case where both links use the same code type. Our results show that in order to minimize the effective symbol loss, the first link should use a triangular block code. Whereas, the second link should use a convolutional or triangular code, with little to no gain of using the former over the latter.","Title: The Effect of Time Delay on the Average Data Rate and Performance in Networked Control Systems\nYear: 2018\n\nAbstract: This article studies the performance of a feedback control loop closed via an error-free digital communication channel with transmission delay. The system comprises a discrete-time noisy linear time-invariant plant, whose single measurement output is mapped into its single control input by a causal, but otherwise arbitrary, coding and control scheme. We consider a single-input multiple-output chan...","Title: Zero-Delay Rate Distortion via Filtering for Vector-Valued Gaussian Sources.\nYear: 2018\n\nAbstract: We deal with zero-delay source coding of a vector-valued Gauss-Markov source subject to a mean-squared error (MSE) fidelity criterion characterized by the operational zero-delay vector-valued Gaussian rate distortion function (RDF). We address this problem by considering the nonanticipative RDF (NRDF), which is a lower bound to the causal optimal performance theoretically attainable function (or s...","Title: On Zero-Delay Source Coding Of Lti Gauss-Markov Systems With Covariance Matrix Distortion Constraints\nYear: 2018\n\nAbstract: We introduce a new class of zero-delay source coding problems where a vector-valued Gauss-Markov source is conveyed subject to covariance matrix distortion constraints. We address this problem by defining an information theoretic measure where we minimize mutual information subject to causality constraints and covariance matrix distortion constraints. The resulting measure serves as a lower bound to the zero-delay rate distortion function (RDF). We solve this problem by showing that it is semidefinite representable and, thus, can be computed numerically. We also show that for this new class of information measures, it is possible to have achievable rates up to a constant space-filling loss due to a vector lattice quantizer and a constant loss due to entropy coding. We corroborate our framework with illustrative simulation examples.","Title: Mean square performance evaluation in frequency domain for an improved adaptive feedback cancellation in hearing aids.\nYear: 2019\n\nAbstract: •Analyzing dependence of system-behaviour of LP-based adaptive feedback canceller with and without probe noise, on adaptive algorithm employed.•For unbiased feedback cancellation using LP-based feedback canceller with shaped probe noise, steady-state error is increased for RLS algorithm.•For NLMS algorithm, cost of unbiased feedback estimate is reduction in rate of convergence, along with an increase in the tracking error.•Loudspeaker output of LP-based feedback canceller with shaped probe noise shows less distortion and whistling problem.•Derived expressions provide accurate approximation of power transfer function, convergence rate and steady-state error for different inputs.","Title: Sound Quality Improvement for Hearing Aids in Presence of Multiple Inputs\nYear: 2019\n\nAbstract: AbstractModern-day hearing aids are capable of receiving acoustic signals over a wireless link and also from the surroundings through the microphone. If the hearing aid receives input only from the acoustic environment, feedback cancellation proceeds according to the existing methodologies for bias reduction. However, the wirelessly received signal and the acoustic environment input, when emitted from the same source, can be very similar to each other or with a time-delayed version of each other, thereby having a high correlation between them. Both inputs can also be emitted from different sources and, thus, be less correlated with each other. In the aforementioned scenarios, acoustic confusion can occur for the user as the hearing aid receives both signals simultaneously. To improve the output signal quality and to reduce bias in an adaptive feedback cancellation system with a wirelessly received signal as well as an acoustic environment input, we propose a cost function, and the optimization of the feed-forward path and of the shaping filter for the wireless signal. The feed-forward path is designed to be a cascade of the required acoustic enhancement along with an FIR filter. We derive expressions for an optimum shaping filter and for an optimized feed-forward path. Improvement in loudspeaker output signal quality, normalized misalignment and maximum stable gain for each of the above-mentioned scenarios is assessed through numerical simulations.","Title: The Entropy Gain Of Linear Systems And Some Of Its Implications\nYear: 2021\n\nAbstract: We study the increase in per-sample differential entropy rate of random sequences and processes after being passed through a non minimum-phase (NMP) discrete-time, linear time-invariant (LTI) filter G. For LTI discrete-time filters and random processes, it has long been established by Theorem 14 in Shannon's seminal paper that this entropy gain, G(G), equals the integral of log|G(e(j omega))|. In this note, we first show that Shannon's Theorem 14 does not hold in general. Then, we prove that, when comparing the input differential entropy to that of the entire (longer) output of G, the entropy gain equals G(G). We show that the entropy gain between equal-length input and output sequences is upper bounded by G(G) and arises if and only if there exists an output additive disturbance with finite differential entropy (no matter how small) or a random initial state. Unlike what happens with linear maps, the entropy gain in this case depends on the distribution of all the signals involved. We illustrate some of the consequences of these results by presenting their implications in three different problems. Specifically: conditions for equality in an information inequality of importance in networked control problems; extending to a much broader class of sources the existing results on the rate-distortion function for non-stationary Gaussian sources, and an observation on the capacity of auto-regressive Gaussian channels with feedback.","Title: Joint Far- and Near-End Speech Intelligibility Enhancement Based on the Approximated Speech Intelligibility Index\nYear: 2022\n\nAbstract: This paper considers speech enhancement of signals picked up in one noisy environment which must be presented to a listener in another noisy environment. Recently, it has been shown that an optimal solution to this problem requires the consideration of the noise sources in both environments jointly. However, the existing optimal mutual information based method requires a complicated system model that includes natural speech variations, and relies on approximations and assumptions of the underlying signal distributions. In this paper, we propose to use a simpler signal model and optimize speech intelligibility based on the Approximated Speech Intelligibility Index (ASII). We derive a closed-form solution to the joint far- and near-end speech enhancement problem that is independent of the marginal distribution of signal coefficients, and that achieves similar performance to existing work. In addition, we do not need to model or optimize for natural speech variations.","Title: Compression of DNNs Using Magnitude Pruning and Nonlinear Information Bottleneck Training\nYear: 2021\n\nAbstract: As Deep Neural Networks (DNNs) have achieved state-of-the-art performance in various scientific fields and applications, the memory and computational complexity of DNNs have increased concurrently. The increased complexity required by DNNs prohibits them from running on platforms with limited computational resources. This has sparked a renewed interest in parameter pruning. We propose to replace t...","Title: A Family of Adaptive Volterra Filters Based on Maximum Correntropy Criterion for Improved Active Control of Impulsive Noise\nYear: 2022\n\nAbstract: Linear active noise control (ANC) systems have been used in the past to effectively suppress Gaussian noise. A practical ANC system must consider nonlinearities in the secondary path with a non-minimum phase. For an ANC system to effectively operate in a modern-day acoustic environment with multiple electrical/electronic systems operating in the vicinity, the reference noise source is taken as a non-Gaussian stochastic process. Linear systems have shown unacceptable performance in countering the disturbances that are impulsive in nature. Considering these issues, we propose a family of adaptive algorithms for ANC systems that employ a second-order Volterra filter for accurate modeling of the impulsive disturbances. We utilize the maximum correntropy criterion as the cost function to improve the adaptive filtering process, which generates the most appropriate output signal in the ANC system's successive iterative stages. The proposed algorithms feature dynamic learning-rate parameters, which improve the tracking performance of the algorithms. Also, a careful selection of the Volterra filter's kernel size in the proposed algorithms ensures a balance between system stability and convergence rate. These parameters are made automatically adjustable, based on the residual error and the reference input signals, to optimize performance in non-Gaussian environments. A comparison of the proposed algorithms with its counterparts is presented through computer simulations in terms of average noise reduction for different levels of impulsive noise. The proposed algorithms are also compared with each other to find the best performing algorithm in a non-Gaussian environment. Achieved results exhibit the effectiveness of the proposed algorithms in their ability to attenuate impulsive noise in comparison with the existing adaptive algorithms for ANC systems. Later, the proposed algorithm has been implemented for speech enhancement, where the noise from the speech sample is identified and removed using an adaptive filter algorithm. Simulations reveal that the devised algorithm can effectively denoise speech signals. Further, in the last part of the paper, the VF-MCCRMC is modified in accordance with the energy of the error signal, and the simulation results demonstrated the improvement in stability and error performance.","Title: Correction to “A Framework for Control System Design Subject to Average Data-Rate Constraints”\nYear: 2022\n\nAbstract: Theorem 4.1 in the 2011 paper “A Framework for Control System Design Subject to Average Data-Rate Constraints” allows one to lower bound average operational data rates in feedback loops (including the situation in which encoder and decoder have side information). Unfortunately, its proof is invalid. In this note, we first state the theorem and explain why its proof is flawed, and then provide a correct proof under weaker assumptions.","Title: Model-Based Estimation of in-Car-Communication Feedback Applied to Speech Zone Detection\nYear: 2022\n\nAbstract: Modern cars provide versatile tools to enhance speech communication. While an in-car communication (ICC) system aims at enhancing communication between the passengers by playing back desired speech via loudspeakers in the car, these loudspeaker signals may disturb a speech enhancement system required for hands-free telephony and automatic speech recognition. In this paper, we focus on speech zone detection, i.e. detecting which passenger in the car is speaking, which is a crucial component of the speech enhancement system. We propose a model-based feedback estimation method to improve robustness of speech zone detection against ICC feedback. Specifically, since the zone detection system typically does not have access to the ICC loudspeaker signals, the proposed method estimates the feedback signal from the observed microphone signals based on a free-field propagation model between the loudspeakers and the microphones as well as the ICC gain. We propose an efficient recursive implementation in the short-time Fourier transform domain using convolutive transfer functions. A realistic simulation study indicates that the proposed method allows to increase the ICC gain by about 6 dB while still achieving robust speech zone detection results.","Title: A Linear MMSE Filter Using Delayed Remote Microphone Signals for Speech Enhancement in Hearing Aid Applications\nYear: 2022\n\nAbstract: Existing methods that use remote microphones with hearing aid (HA) noise reduction systems, assume the wireless transmission to be instantaneous. In practice, however, there exists a time difference of arrival (TDOA) between the wirelessly transmitted target signals and the acoustic signal arriving from the target source to the HA device, which degrades their noise reduction performance. As speech is correlated between consecutive time-frames in the short-time Fourier transform (STFT) domain, we propose a linear minimum mean-square error (MMSE) estimator to estimate the desired signal, by combining multiple HA microphone signals with multiple consecutive time-frames of the remote microphone signal. We derive closed form expressions for the resulting filter weights and interpret them in terms of existing multi-channel and multi-frame methods. The simulation results validate the interpretation and show that using a multi-frame method along with a multi-channel method is an advantage, in the presence of unknown, positive TDOA between the microphone signals."],"string":"[\n \"Title: Correction to \\\"Packetized Predictive Control of Stochastic Systems Over Bit-Rate Limited Channels With Packet Loss\\\".\\nYear: 2013\\n\\nAbstract: The authors correct the results in Section V of the above-named article (ibid., vol. 56, no. 12, pp. 2854-2868, Dec. 2011).\",\n \"Title: Achieving the Quadratic Gaussian Rate-Distortion Function for Source Uncorrelated Distortions\\nYear: 2008\\n\\nAbstract: We prove achievability of the recently characterized quadratic Gaussian\\nrate-distortion function (RDF) subject to the constraint that the distortion is\\nuncorrelated to the source. This result is based on shaped dithered lattice\\nquantization in the limit as the lattice dimension tends to infinity and holds\\nfor all positive distortions. It turns out that this uncorrelated distortion\\nRDF can be realized causally. This feature, which stands in contrast to\\nShannon's RDF, is illustrated by causal transform coding. Moreover, we prove\\nthat by using feedback noise shaping the uncorrelated distortion RDF can be\\nachieved causally and with memoryless entropy coding. Whilst achievability\\nrelies upon infinite dimensional quantizers, we prove that the rate loss\\nincurred in the finite dimensional case can be upper-bounded by the space\\nfilling loss of the quantizer and, thus, is at most 0.254 bit/dimension.\",\n \"Title: Ripple design of LT codes for AWGN channel.\\nYear: 2012\\n\\nAbstract: In this paper, we present an analytical framework for designing LT codes in additive white Gaussian noise (AWGN) channels. We show that some of analytical results from binary erasure channels (BEC) also hold in AWGN channels with slight modifications. This enables us to apply a ripple-based design approach, which until now has only been used in the BEC. LT codes designed by this way show promising performance which is near the Shannon limit even with short codewords.\",\n \"Title: Ripple Design of LT Codes for BIAWGN Channels.\\nYear: 2014\\n\\nAbstract: This paper presents a novel framework, which enables a design of rateless codes for binary input additive white Gaussian noise (BIAWGN) channels, using the ripple-based approach known from the works for the binary erasure channel (BEC). We reveal that several aspects of the analytical results from the BEC also hold in BIAWGN channels. The presented framework is applied in a code design example, which shows promising results compared to existing work. In particular it shows a great robustness towards variations in the signal-to-noise power ratio (SNR), contrary to existing codes.\",\n \"Title: Multiple Description Coding with Feedback Based Network Compression\\nYear: 2010\\n\\nAbstract: This paper concerns multi path video streaming using adaptive multiple description coding. The adaptation leverages on the fact that multiple descriptions are correlated. Thus if an intermediate node gets feedback telling that another path is likely to deliver a description, this node can compress its description and forward it. Such a compression can also be done already at the source node; however, the feedback arrives more timely and reliably to intermediate nodes that are closer to the final receiver. In this paper we investigate the performance of such adaptation at the source node and an intermediate node, respectively. A trade-off exists between reducing the delay of the feedback by adapting in the vicinity of the receiver and increasing the gain from compression by adapting close to the source. The analysis shows that adaptation in the network provides a better trade-off than adaptation at the source. Schemes which provide simple solutions to adaptation both at the source and in the network are proposed, analyzed, simulated and compared to non-adaptive reference schemes in scenarios that involve last hop that is wireless. The results reveal that the proposed compression schemes offer significant benefits in streaming scenarios.\",\n \"Title: Power Control and Coding Formulation for State Estimation with Wireless Sensors.\\nYear: 2014\\n\\nAbstract: Technological advances made wireless sensors cheap and reliable enough to be brought into industrial use. A major challenge arises from the fact that wireless channels introduce random packet dropouts. Power control and coding are key enabling technologies in wireless communications to ensure efficient communication. In this paper, we examine the role of power control and coding for Kalman filtering over wireless correlated channels. Two estimation architectures are considered; initially, the sensors send their measurements directly to a single gateway (GW). Next, wireless relay nodes provide additional links. The GW decides on the coding scheme and the transmitter power levels of the wireless nodes. The decision process is carried out online and adapts to varying channel conditions to improve the tradeoff between state estimation accuracy and energy expenditure. In combination with predictive power control, we investigate the use of multiple-description coding (MDC), zero-error coding (ZEC), and network coding and provide sufficient conditions for the expectation of the estimation error covariance matrix to be bounded. Numerical results suggest that the proposed method may lead to energy savings of around 50%, when compared with an alternative scheme, wherein transmission power levels and bit-rates are governed by simple logic. In particular, ZEC is preferable at time instances with high channel gains, whereas MDC is superior for time instances with low gains. When channels between the sensors and the GW are in deep fades, network coding improves estimation accuracy significantly without sacrificing energy efficiency.\",\n \"Title: UEP LT Codes with Intermediate Feedback.\\nYear: 2013\\n\\nAbstract: We analyze a class of rateless codes, called Luby transform (LT) codes with unequal error protection (UEP). We show that while these codes successfully provide UEP, there is a significant price in terms of redundancy in the lower prioritized segments. We propose a modification with a single intermediate feedback message. Our analysis shows a dramatic improvement on the decoding performance of the lower prioritized segment.\",\n \"Title: A Framework for Control System Design Subject to Average Data-Rate Constraints.\\nYear: 2011\\n\\nAbstract: This paper studies discrete-time control systems subject to average data-rate limits. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source-coding scheme (with unity signal transfer function) has to be deployed in the feedback path. For this situation, and by focusing on a class of source-coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. As an illustration of the uses of our framework, we apply it to study the interplay between stability and average data-rates in the considered architecture. It is shown that the proposed class of coding schemes can achieve mean square stability at average data-rates that are, at most, 1.254 bits per sample away from the absolute minimum rate for stability established by Nair and Evans. This rate penalty is compensated by the simplicity of our approach.\",\n \"Title: The Quadratic Gaussian Rate-Distortion Function for Source Uncorrelated Distortions\\nYear: 2008\\n\\nAbstract: We characterize the rate-distortion function for zero-mean stationary Gaussian sources under the MSE fidelity criterion and subject to the additional constraint that the distortion is uncorrelated to the input. The solution is given by two equations coupled through a single scalar parameter. This has a structure similar to the well known water-filling solution obtained without the uncorrelated distortion restriction. Our results fully characterize the unique statistics of the optimal distortion. We also show that, for all positive distortions, the minimum achievable rate subject to the uncorrelation constraint is strictly larger than that given by the un-constrained rate-distortion function. This gap increases with the distortion and tends to infinity and zero, respectively, as the distortion tends to zero and infinity.\",\n \"Title: Sparse command generator for remote control\\nYear: 2011\\n\\nAbstract: In this article, we consider remote-controlled systems, where the command generator and the controlled object are connected with a bandwidth-limited communication link. In the remote-controlled systems, efficient representation of control commands is one of the crucial issues because of the bandwidth limitations of the link. We propose a new representation method for control commands based on compressed sensing. In the proposed method, compressed sensing reduces the number of bits in each control signal by representing it as a sparse vector. The compressed sensing problem is solved by an ℓ1-ℓ2 optimization, which can be effectively implemented with an iterative shrinkage algorithm. A design example also shows the effectiveness of the proposed method.\",\n \"Title: l1 Compression of Image Sequences Using the Structural Similarity Index Measure\\nYear: 2009\\n\\nAbstract: We consider lossy compression of image sequences using l1-compression with overcomplete dictionaries. As a fidelity measure for the reconstruction quality, we incorporate the recently proposed structural similarity index measure, and we show that this leads to problem formulations that are very similar to conventional l1 compression algorithms. In addition, we develop efficient large-scale algorithms used for joint encoding of multiple image frames.\",\n \"Title: n-channel entropy-constrained multiple-description lattice vector quantization\\nYear: 2006\\n\\nAbstract: In this paper, we derive analytical expressions for the central and side quantizers which, under high-resolution assumptions, minimize the expected distortion of a symmetric multiple-description lattice vector quantization (MD-LVQ) system subject to entropy constraints on the side descriptions for given packet-loss probabilities. We consider a special case of the general n-channel symmetric multiple-description problem where only a single parameter controls the redundancy tradeoffs between the central and the side distortions. Previous work on two-channel MD-LVQ showed that the distortions of the side quantizers can be expressed through the normalized second moment of a sphere. We show here that this is also the case for three-channel MD-LVQ. Furthermore, we conjecture that this is true for the general n-channel MD-LVQ. For given source, target rate, and packet-loss probabilities we find the optimal number of descriptions and construct the MD-LVQ system that minimizes the expected distortion. We verify theoretical expressions by numerical simulations and show in a practical setup that significant performance improvements can be achieved over state-of-the-art two-channel MD-LVQ by using three-channel MD-LVQ.\",\n \"Title: Energy efficient state estimation with wireless sensors through the use of predictive power control and coding\\nYear: 2010\\n\\nAbstract: We study state estimation via wireless sensors over fading channels. Packet loss probabilities depend upon time-varying channel gains, packet lengths and transmission power levels of the sensors. Measurements are coded into packets by using either independent coding or distributed zero-error coding. At the gateway, a time-varying Kalman filter uses the received packets to provide the state estimates. To trade sensor energy expenditure for state estimation accuracy, we develop a predictive control algorithm which, in an online fashion, determines the transmission power levels and codebooks to be used by the sensors. To further conserve sensor energy, the controller is located at the gateway and sends coarsely quantized power increment commands, only whenever deemed necessary. Simulations based on real channel measurements illustrate that the proposed method gives excellent results.\",\n \"Title: Fixed-Lag Smoothing for Low-Delay Predictive Coding with Noise Shaping for Lossy Networks\\nYear: 2010\\n\\nAbstract: We consider linear predictive coding and noise shaping for coding and transmission of auto-regressive (AR) sources over lossy networks. We generalize an existing framework to arbitrary filter orders and propose use of fixed-lag smoothing at the decoder, in order to further reduce the impact of transmission failures. We show that fixed-lag smoothing up to a certain delay can be obtained without additional computational complexity by exploiting the state-space structure. We prove that the proposed smoothing strategy strictly improves performance under quite general conditions. Finally, we provide simulations on AR sources, and channels with correlated losses, and show that substantial improvements are possible.\",\n \"Title: The high-resolution rate-distortion function under the structural similarity index\\nYear: 2011\\n\\nAbstract: We show that the structural similarity (SSIM) index, which is used in image processing to assess the similarity between an image representation and an original reference image, can be formulated as a locally quadratic distortion measure. We, furthermore, show that recent results of Linder and Zamir on the rate-distortion function (RDF) under locally quadratic distortion measures are applicable to this SSIM distortion measure. We finally derive the high-resolution SSIM-RDF and provide a simple method to numerically compute an approximation of the SSIM-RDF of real images.\",\n \"Title: Distributed remote vector gaussian source coding with covariance distortion constraints\\nYear: 2014\\n\\nAbstract: In this paper, we consider a distributed remote source coding problem, where a sequence of observations of source vectors is available at the encoder. The problem is to specify the optimal rate for encoding the observations subject to a covariance matrix distortion constraint and in the presence of side information at the decoder. For this problem, we derive lower and upper bounds on the rate-distortion function (RDF) for the Gaussian case, which in general do not coincide. We then provide some cases, where the RDF can be derived exactly. We also show that previous results on specific instances of this problem can be generalized using our results. We finally show that if the distortion measure is the mean squared error, or if it is replaced by a certain mutual information constraint, the optimal rate can be derived from our main result.\",\n \"Title: Sparse Packetized Predictive Control for Networked Control Over Erasure Channels.\\nYear: 2013\\n\\nAbstract: We study feedback control over erasure channels with packet-dropouts. To achieve robustness with respect to packet-dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. To reduce the data size of packets, we propose to adopt sparsity-promoting optimizations, namely, l 1 - l 2 and l 2 -constrained l 0 optimizations, for which efficient algorithms exist. We show how to design the tuning parameters to ensure (practical) stability of the resulting feedback control systems when the number of consecutive packet-dropouts is bounded.\",\n \"Title: n-Channel Symmetric Multiple-Description Lattice Vector Quantization\\nYear: 2005\\n\\nAbstract: We derive analytical expressions for the central and side quantizers in an n-channel symmetric multiple-description lattice vector quantizer which, under high-resolution assumptions, minimize the expected distortion subject to entropy constraints on the side descriptions for given packet-loss probabilities. The performance of the central quantizer is lattice dependent whereas the performance of the side quantizers is lattice independent. In fact the normalized second moments of the side quantizers are given by that of an L-dimensional sphere. Furthermore, our analytical results reveal a simple way to determine the optimum number of descriptions. We verify theoretical results with numerical experiments and show that with a packet-loss probability of 5%, a gain of 9.1 dB in MSE over state-of-the-art two-description systems can be achieved when quantizing a two-dimensional unit-variance Gaussian source using a total bit budget of 15 bits/dimension and using three descriptions. With 20% packet loss, a similar experiment reveals an MSE reduction of 10.6 dB when using four descriptions.\",\n \"Title: Bounding the Rate Region of Vector Gaussian Multiple Descriptions with Individual and Central Receivers\\nYear: 2010\\n\\nAbstract: The problem of the rate region of the vector Gaussian multiple description with individual and central quadratic distortion constraints is studied. We have two main contributions. First, a lower bound on the rate region is derived. The bound is obtained by lower-bounding a weighted sum rate for each supporting hyperplane of the rate region. Second, the rate region for the scenario of the scalar Gaussian source is fully characterized by showing that the lower bound is tight. The optimal weighted sum rate for each supporting hyperplane is obtained by solving a single maximization problem. This is contrary to existing results, which require solving a min-max optimization problem.\",\n \"Title: Multiple-Description Lattice Vector Quantization\\nYear: 2007\\n\\nAbstract: Abstract— In this paper we derive analytical expressions for the central and side quantizers which, under high-resolutions assumptions, minimize the expected distortion of a symmetric multiple-description lattice vector quantization (MD-LVQ) system subject to entropy constraints on the side descriptions for given packet-loss probabilities. We consider a special case of the general n-channel symmetric multiple-description problem,where,only a single parameter controls the redundancy tradeoffs between the central and the side distortions. Previous work on two-channel MD-LVQ showed that the distortions of the side quantizers can be expressed through the normalized second moment,of a sphere. We show here that this is also the case for three-channel MD-LVQ. Furthermore, we conjecture that this is true for the general nchannel MD-LVQ. For given source, target rate and packet-loss probabilities we find the optimal number,of descriptions and construct the MDLVQ system that minimizes the expected distortion. We verify theoretical expressions by numerical simulations and show in a practical setup that significant performance improvements,can be achieved over state-of-the-art two-channel MD-LVQ by using three-channel MD-LVQ. Index Terms— high-rate quantization, lattice quantization,\",\n \"Title: Predictive power control and multiple-description coding for wireless sensor networks\\nYear: 2009\\n\\nAbstract: We study state estimation via wireless sensor networks over fading channels affected by random packet loss. In the configuration examined, the sensors send their measurements to a single gateway, which decides upon the source coding scheme and the sensor transmitter power levels. The decision process is carried out on-line and adapts to changing channel conditions to achieve an optimal trade-off between estimation quality and sensor energy expenditure. In particular, if some channel conditions are poor, then the gateway commands the corresponding sensors to increase power levels and use multiple-description coding. Simulations based on measured channel data illustrate that the proposed scheme gives excellent results.\",\n \"Title: Noise-Shaped Predictive Coding for Multiple Descriptions of a Colored Gaussian Source\\nYear: 2008\\n\\nAbstract: It was recently shown that the symmetric multiple-description (MD) quadratic rate-distortion function for memoryless Gaussian sources and two descriptions can be achieved by dithered Delta-Sigma quantization combined with memoryless entropy coding. In this paper,we generalize this result to stationary (colored) Gaussian sources by combining noise shaping and source prediction. We first propose a new representation for the test channel that realizes the MD rate-distortion function of a Gaussian source, both in the white and in the colored source case. We then show that this test channel canbe materialized by embedding two source prediction loops, one for each description, within a common noise shaping loop. While the noise shaping loop controls the tradeoff between the side and the central distortions, the role of prediction (like in differential pulse code modulation) is to extract the source innovations from the reconstruction at each of the side decoders, and thus reduce the coding rate. Finally, we show that this scheme achieves the MD rate-distortion function at all resolutions and all side-to-central distortion ratios, in the limit of high dimensional quantization.\",\n \"Title: Analysis of LT Codes with Unequal Recovery Time\\nYear: 2012\\n\\nAbstract: In this paper we analyze a specific class of rateless codes, called LT codes with unequal recovery time. These codes provide the option of prioritizing different segments of the transmitted data over other. The result is that segments are decoded in stages during the rateless transmission, where higher prioritized segments are decoded at lower overhead. Our analysis focuses on quantifying the expected amount of received symbols, which are redundant already upon arrival, i.e. all input symbols contained in the received symbols have already been decoded. This analysis gives novel insights into the probabilistic mechanisms of LT codes with unequal recovery time, which has not yet been available in the literature. We show that while these rateless codes successfully provide the unequal recovery time, they do so at a significant price in terms of redundancy in the lower prioritized segments. We propose and analyze a modification where a single intermediate feedback is transmitted, when the first segment is decoded in a code with two segments. Our analysis shows that this modification provides a dramatic improvement on the decoding performance of the lower prioritized segment.\",\n \"Title: Colored Gaussian Multiple Descriptions: Spectral-Domain Characterization and Time-Domain Design\\nYear: 2010\\n\\nAbstract: It is well known that Shannon's rate-distortion function (RDF) in the colored\\nquadratic Gaussian (QG) case, can be parametrized via a single Lagrangian\\nvariable (the ``water level'' in the reverse water filling solution). In this\\nwork, we show that the symmetric colored QG multiple-description (MD) RDF in\\nthe case of two descriptions, can be parametrized via two Lagrangian variables.\\nTo establish this result, we use two key ideas. First, we propose a new\\nrepresentation for the MD test channel, and show that the minimum mutual\\ninformation rate across this channel coincide with the QG MD RDF. Second, we\\nuse variational calculus to obtain a spectral domain representation of the test\\nchannel's optimal side and central distortion spectra given the source spectral\\ndensity and the side and central distortion constraints. The distortion spectra\\nare specified via two Lagrangian parameters, which control the trade-off\\nbetween the side distortion, the central distortion, and the coding rate.We\\nalso show that the symmetric colored QG MD RDF can be achieved by noise-shaped\\npredictive coding, dithered quantization, and memoryless entropy coding. In\\nparticular, we show that the proposed MD test channel can be materialized by\\nembedding two source prediction loops, one for each description, within a\\ncommon noise shaping loop whose parameters are explicitly found from the\\nspectral-domain characterization. The source prediction loops exploit the\\nsource memory, and thus reduce the coding rate. The noise-shaping loop,\\ncontrols the trade-off between the side and the central distortions by shaping\\nthe quantization noise.\",\n \"Title: N-Channel Asymmetric Multiple-Description Lattice Vector Quantization\\nYear: 2005\\n\\nAbstract: We present analytical expressions for optimal entropy-constrained multiple-description lattice vector quantizers which, under high-resolutions assumptions, minimize the expected distortion for given packet-loss probabilities. We consider the asymmetric case where packet-loss probabilities and side entropies are allowed to be unequal and find optimal quantizers for any number of descriptions in any dimension. We show that the normalized second moments of the side-quantizers are given by that of an L-dimensional sphere independent of the choice of lattices. Furthermore, we show that the optimal bit-distribution among the descriptions is not unique. In fact, within certain limits, bits can be arbitrarily distributed.\",\n \"Title: On the Role of Feedback in LT Codes\\nYear: 2010\\n\\nAbstract: This paper concerns application of feedback in LT codes. The considered type\\nof feedback is acknowledgments, where information on which symbols have been\\ndecoded is given to the transmitter. We identify an important adaptive\\nmechanism in standard LT codes, which is crucial to their ability to perform\\nwell under any channel conditions. We show how precipitate application of\\nacknowledgments can interfere with this adaptive mechanism and lead to\\nsignificant performance degradation. Moreover, our analysis reveals that even\\nsensible use of acknowledgments has very low potential in standard LT codes.\\nMotivated by this, we analyze the impact of acknowledgments on multi layer LT\\ncodes, i.e. LT codes with unequal error protection. In this case, feedback\\nproves advantageous. We show that by using only a single feedback message, it\\nis possible to achieve a noticeable performance improvement compared to\\nstandard LT codes.\",\n \"Title: Sequential remote source coding in wireless acoustic sensor networks.\\nYear: 2012\\n\\nAbstract: In this paper, we consider source coding in wireless acoustic sensor networks (WASNs). A WASN is a network of sensors, where each sensor is equipped with a microphone and thereby forming a distributed microphone array. In addition to a microphone, the sensors communicate via radio channels. Thus, a sensor observes an acoustic noisy measurement in addition to receiving a coded correlated noisy measurement from a neighboring sensor node. Given a set of sensors, the problem is to efficiently encode the noisy observations and/or reencode the received coded noisy observations. Furthermore, one seeks a routing strategy that e. g., minimizes the sum rate subject to some distortion constraints. Towards that end, we define a new source coding concept related to WASNs which we denote sequential remote source coding, and present an achievable rate region in the quadratic Gaussian case.\",\n \"Title: Sequential Error Concealment for Video/Images by Sparse Linear Prediction\\nYear: 2013\\n\\nAbstract: In this paper, we propose a novel sequential error concealment algorithm for video and images based on sparse linear prediction. Block-based coding schemes in packet loss environments are considered. Images are modelled by means of linear prediction, and missing macroblocks are sequentially reconstructed using the available groups of pixels. The optimal predictor coefficients are computed by applying a missing data regression imputation procedure with a sparsity constraint. Moreover, an efficient procedure for the computation of these coefficients based on an exponential approximation is also proposed. Both techniques provide high-quality reconstructions and outperform the state-of-the-art algorithms both in terms of PSNR and MS-SSIM.\",\n \"Title: Fundamental Inequalities and Identities Involving Mutual and Directed Informations in Closed-Loop Systems\\nYear: 2013\\n\\nAbstract: We present several novel identities and inequalities relating the mutual information and the directed information in systems with feedback. The internal blocks within such systems are restricted only to be causal mappings, but are allowed to be non-linear, stochastic and time varying. Moreover, the involved signals can be arbitrarily distributed. We bound the directed information between signals inside the feedback loop by the mutual information between signals inside and outside the feedback loop. This fundamental result has an interesting interpretation as a law of conservation of information flow. Building upon it, we derive several novel identities and inequalities, which allow us to prove some existing information inequalities under less restrictive assumptions. Finally, we establish new relationships between nested directed informations inside a feedback loop. This yields a new and general data-processing inequality for systems with feedback.\",\n \"Title: Design and Analysis of LT Codes with Decreasing Ripple Size\\nYear: 2012\\n\\nAbstract: In this paper we propose a new design of LT codes, which decreases the amount of necessary overhead in comparison to existing designs. The design focuses on a parameter of the LT decoding process called the ripple size. This parameter was also a key element in the design proposed in the original work by Luby. Specifically, Luby argued that an LT code should provide a constant ripple size during de...\",\n \"Title: Sparsely-Packetized Predictive Control by Orthogonal Matching Pursuit.\\nYear: 2013\\n\\nAbstract: We study packetized predictive control, known to be robust against packet dropouts in networked systems. To obtain sparse packets for rate-limited networks, we design control packets via an l0 optimization, which can be effectively solved by orthogonal matching pursuit. Our formulation ensures asymptotic stability of the control loop in the presence of bounded packet dropouts. 1. Packetized Predictive Control. Let us consider the following discretetime, LTI plant model with a scalar input: x(k + 1) = Ax(k) +Bu(k), k ∈ N0, x(0) = x0, (1.1) where x(k) ∈ R and u(k) ∈ R for k ∈ N0. We assume that (A,B) is reachable. We are interested in a networked control architecture where the controller communicates with the plant actuator through an erasure channel, see Fig. 1.1. This channel introduces bounded packet-dropouts. In packetized predictive control (PPC), as described, e.g., in [4, 2] at each time instant k, the controller uses the state x(k) of the plant (1.1) to calculate and send a control packet of the form u ( x(k) ) , [ u0 ( x(k) ) , u1 ( x(k) ) , . . . , uN−1 ( x(k) )]⊤ ∈ R (1.2) to the plant input node. To achieve robustness against packet dropouts, buffering is used. To be more specific, suppose that at time instant k the data packet u(x(k)) defined in (1.2) is successfully received at the plant input side. Then, this packet is stored in a buffer, overwriting its previous contents. If the next packet, u(x(k+1)), is dropped, then the plant input u(k+1) is set to u1(x(k)), the second element of u(x(k)). The subsequent elements of u(x(k)) are then successively used until some control packet u(x(k+ l)), l ≥ 2, is successfully received, i.e., no dropout occurs. 2. Sparse Control Packet Design for Asymptotic Stability. In the PPC method discussed above, control packets u(x(k)) are transmitted at each time k ∈ N0 through an erasure channel. It is often the case that the bandwidth of the channel is limited, and hence one has to compress control packets to a smaller data size. To achieve an efficient compression of packets, we adopt a technique developed in compressed sensing [1] that considers the sparsity of a signal (or a vector). A sparse vector contains many 0-valued elements and can be highly compressed by only coding ∗This research was supported in part under the MEXT (Japan) Grant-in-Aid for Young Scientists (B) No. 22760317, and also Australian Research Council’s Discovery Projects funding scheme (project number DP0988601). †Graduate School of Informatics, Kyoto University, Kyoto, 606-8501, Japan; e-mail: nagahara@ieee.org ‡School of Electrical Engineering u0026 Computer Science, The University of Newcastle, NSW 2308, Australia; e-mail:dquevedo@ieee.org §Department of Electronic Systems, Aalborg University, Denmark; e-mail: janoe@ieee.org Controller Buffer Plant x(k) u(x(k)) u(k) Fig. 1.1. Networked Control System with PPC its few nonzero components. Based on this notion, in [2] we presented a sparsityinducing l/l optimization for PPC which gives practical stability, i.e., existence of a bounded invariant set. In the present work, we embellish the approach of [2] by showing how to find sparse control packets u(x(k)) ensuring that the networked system with bounded packet dropouts is asymptotically stable. For this, we propose to design the control packets via the following sparsity-promoting optimization: u(x(k)) , argmin u∈RN ∥u∥0 subject to ∥xN |k∥P + N−1 ∑ i=0 ∥xi|k∥Q ≤ x(k)⊤Wx(k), (2.1) where ∥u∥0 is the number of the nonzero elements in u = [u0, u1, . . . , uN−1] and x0|k = x, xi+1|k = Axi|k +Bui, i = 0, 1, . . . , N − 1. (2.2) In (2.2), N is the horizon length, taken here equal to the buffer size. The matrix Q u003e 0 is a design parameter which allows one to shape the response of the plant state components; P u003e 0 and W u003e 0 are chosen such that the feedback system is asymptotically stable, as indicated in Theorem 2.1 below. To state our subsequent results, we introduce the matrices Φ, Υ and Q by Φ , B 0 . . . 0 AB B . . . 0 .. .. . . . .. AN−1B AN−2B . . . B , Υ , A A .. A , Q , blockdiag{Q, . . . , Q } {{ } N−1 , P}. Theorem 2.1 (Asymptotic Stability). Assume that the number of consecutive packet-dropouts is uniformly bounded by N . Suppose the matrices P , Q, and W are chosen by the following procedure: i. Choose Q u003e 0 arbitrarily. ii. Solve the following Riccati equation to obtain P u003e 0: P = A⊤PA−A⊤PB(B⊤PB)−1B⊤PA+Q. (2.3) iii. Compute the constants ρ ∈ [0, 1) and c u003e 0 via ρ , 1− λmin(QP), c , 1− ρ 1− ρ max i λmax { Φi PΦi(Φ ⊤QΦ)−1 } , where Φi is the i-th column of matrix Φ. iv. Choose a matrix E such that 0 u003c E u003c (1− ρ)P/c. v. Set W := P −Q+ E. Then for any choice of the control vector from the feasible set of the optimization (2.1) (which includes the sparsest control packets u(x(k))), the networked control system is asymptotically stable, that is, limk→∞ x(k) = 0. 0 10 20 30 40 50 60 70 80 90 100 10 −30 10 −20 10 −10 10 0 2−norm of the state x(k)\",\n \"Title: N-channel asymmetric entropy-constrained multiple-description lattice vector quantization\\nYear: 2010\\n\\nAbstract: This paper is about the design and analysis of an index-assignment (IA)-based multiple-description coding scheme for the n-channel asymmetric case. We use entropy constrained lattice vector quantization and restrict attention to simple reconstruction functions, which are given by the inverse IA function when all descriptions are received or otherwise by a weighted average of the received descriptions. We consider smooth sources with finite differential entropy rate and MSE fidelity criterion. As in previous designs, our construction is based on nested lattices which are combined through a single IA function. The results are exact under high-resolution conditions and asymptotically as the nesting ratios of the lattices approach infinity. For any n, the design is asymptotically optimal within the class of IA-based schemes. Moreover, in the case of two descriptions and finite lattice vector dimensions greater than one, the performance is strictly better than that of existing designs. In the case of three descriptions, we show that in the limit of large lattice vector dimensions, points on the inner bound of Pradhan et al. can be achieved. Furthermore, for three descriptions and finite lattice vector dimensions, we show that the IA-based approach yields, in the symmetric case, a smaller rate loss than the recently proposed source-splitting approach.\",\n \"Title: Iterated Smoothing For Accelerated Gradient Convex Minimization In Signal Processing\\nYear: 2010\\n\\nAbstract: In this paper, we consider the problem of minimizing a non-smooth convex problem using first-order methods. The number of iterations required to guarantee a certain accuracy for such problems is often excessive and several methods, e.g., restart methods, have been proposed to speed-up the convergence. In the restart method a smoothness parameter is adjusted such that smoother approximations of the original non-smooth problem are solved in a sequence before the original, and the previous estimate is used as the starting point each time. Instead of adjusting the smoothness parameter after each restart, we propose a method where we modify the smoothness parameter in each iteration. We prove convergence and provide simulation examples for two typical signal processing applications, namely total variation denoising and l(1)-norm minimization. The simulations demonstrate that the proposed method require fewer iterations and show lower complexity compared to the restart method.\",\n \"Title: High-Rate Analysis of Symmetric L-Channel Multiple Description Coding.\\nYear: 2011\\n\\nAbstract: This paper studies the tight rate-distortion bound for L-channel symmetric multiple-description coding of a scalar Gaussian source with two levels of receivers. Each of the first-level receivers obtains κ of the L descriptions (κ <; L). The second-level receiver obtains all L descriptions. We find that if the central distortion (corresponding to the second-level receiver) is much smaller than the ...\",\n \"Title: Practical design of delta-sigma multiple description audio coding.\\nYear: 2014\\n\\nAbstract: It was recently shown that delta-sigma quantization (DSQ) can be used for optimal multiple description (MD) coding of Gaussian sources. The DSQ scheme combined oversampling, prediction, and noise-shaping in order to trade off side distortion for central distortion in MD coding. It was shown that asymptotically in the dimensions of the resampling, prediction, and noise-shaping filters as well as asymptotically in the quantizer dimensions, all rate-distortion points on the symmetric quadratic Gaussian MD rate-distortion function could be achieved. In this work, we show that this somewhat theoretical framework is suitable for practical low-delay MD audio coding. In particular, we design a practical MD audio coder with two descriptions and provide simulations on real audio data. The simulations demonstrate that even when using low-dimensional noise-shaping, prediction, and resampling filters, it is possible to obtain good quality audio in the presence of packet losses. Simulations on real audio reveal that, contrary to existing designs, it is straightforward to obtain a large number of trade-off points between side distortion and central distortion, which makes the proposed coder suitable for a wide range of applications.\",\n \"Title: Improved Upper Bounds to the Causal Quadratic Rate-Distortion Function for Gaussian Stationary Sources\\nYear: 2012\\n\\nAbstract: We improve the existing achievable rate regions for causal and for zero-delay source coding of stationary Gaussian sources under an average mean squared error distortion measure. To begin with, we find a closed-form expression for the information-theoretic causal rate-distortion function (RDF) under such distortion measure, denoted by $R_{c}^{it}(D)$ , for first-order Gauss–Markov processes. $R_{c}^{it}(D)$ is a lower bound to the optimal performance theoretically attainable (OPTA) by any causal source code, namely $R_{c}^{op}(D)$ . We show that, for Gaussian sources, the latter can also be upper bounded as $R_{c}^{op}(D) \\\\\\\\leq R_{c}^{it}(D) + 0.5\\\\\\\\log _{2}(2\\\\\\\\pi {\\\\\\\\rm e}^{})$ bits/sample. In order to analyze $R_{c}^{it}(D)$ for arbitrary zero-mean Gaussian stationary sources, we introduce $\\\\\\\\overline {R_{c}^{it}}(D)$ , the information-theoretic causal RDF when the reconstruction error is jointly stationary with the source. Based upon $\\\\\\\\overline {R_{c}^{it}}(D)$, we derive three closed-form upper bounds to the additive rate loss defined as $\\\\\\\\overline {{R}_{c}^{it}}(D) - R(D)$ , where $R(D)$ denotes Shannon's RDF. Two of these bounds are strictly smaller than 0.5 bits/sample at all rates. These bounds differ from one another in their tightness and ease of evaluation; the tighter the bound, the more involved its evaluation. We then show that, for any source spectral density and any positive distortion $D\\\\\\\\leq \\\\\\\\sigma _{x}^{2}$, $\\\\\\\\overline {R_{c}^{it}}(D)$ can be realized by an additive white Gaussian noise channel surrounded by a unique set of causal pre-, post-, and feedback filters. We show that finding such filters constitutes a convex optimization problem. In order to solve the latter, we propose an iterative optimization procedure that yields the optimal filters and is guaranteed to converge to $\\\\\\\\overline {R_{c}^{it}}(D)$ . Finally, by establishing a connection to feedback quantization, we design a causal and a zero-delay coding scheme which, for Gaussian sources, achieves an operational rate lower than $\\\\\\\\overline {R_{c}^{it}}(D) + 0.254$ and $\\\\\\\\overline {R_{c}^{it}}(D) + 0.754$ bits/sample, respectively. This implies that the OPTA among all zero-delay source codes, denoted by $R_{zd}^{op}(D)$, is upper bounded as $R_{zd}^{op}(D)< \\\\\\\\overline {R_{c}^{it}}(D) + 1.254 < R(D) + 1.754$ bits/sample.\",\n \"Title: Audio coding in wireless acoustic sensor networks.\\nYear: 2015\\n\\nAbstract: In this paper, we consider the problem of source coding for a wireless acoustic sensor network where each node in the network makes its own noisy measurement of the sound field, and communicates with other nodes in the network by sending and receiving encoded versions of the measurements. To make use of the correlation between the sources available at the nodes, we consider the possibility of combining the measurement and the received messages into one single message at each node instead of forwarding the received messages and separate encoding of the measurement. Moreover, to exploit the correlation between the messages received by a node and the node׳s measurement of the source, we propose to use the measurement as side information and thereby form a distributed source coding (DSC) problem. Assuming that the sources are Gaussian, we then derive the rate-distortion function (RDF) for the resulting remote DSC problem under covariance matrix distortion constraints. We further show that for this problem, the Gaussian source is the worst to code. Thus, the Gaussian RDF provides an upper bound to other sources such as audio signals. We then turn our attention to audio signals. We consider an acoustical model based on the room impulse response (RIR) and provide simulation results for the rate-distortion performance in a practical setup where a set of microphones record the sound in a standard listening room. Since our reconstruction scheme and distortion measure are defined over the direct sound source, coding and dereverberation are performed in a joint manner.\",\n \"Title: A Characterization of the Minimal Average Data Rate that Guarantees a Given Closed-Loop Performance Level.\\nYear: 2014\\n\\nAbstract: This paper studies networked control systems closed over noiseless digital channels. We focus on noisy linear time-invariant (LTI) plants with stationary Gaussian disturbances, Gaussian initial state, scalar-valued control inputs and sensor outputs. For this set-up, we show that the absolute minimal directed information rate that allows one to achieve a prescribed level of performance (not necessarily stationary), over all combinations of encoder-controller-decoder, is achieved when the decoder output is jointly Gaussian with the other signals in the system. This directed information rate lower bounds the achievable operational data rates. When restricting our attention to encoder-controller-decoders which make the random processes in the loop (strongly) asymptotically wide-sense stationary, this bound can be expressed in terms of their asymptotic power spectral densities. Then we show that the directed information rate and stationary performance of any such scheme can be achieved when the concatenated encoder, channel, controller and decoder behave as an AWGN channel with LTI filters. We also present a simple coding scheme that allows one to achieve (operational) average data rates that are at most (approximately) 1.254 bits away from the derived lower bound, while satisfying the performance constraint. A numerical example is presented to illustrate our findings.\",\n \"Title: Distributed Remote Vector Gaussian Source Coding for Wireless Acoustic Sensor Networks\\nYear: 2014\\n\\nAbstract: In this paper, we consider the problem of remote vector Gaussian source coding for a wireless acoustic sensor network. Each node receives messages from multiple nodes in the network and decodes these messages using its own measurement of the sound field as side information. The node's measurement and the estimates of the source resulting from decoding the received messages are then jointly encoded and transmitted to a neighbouring node in the network. We show that for this distributed source coding scenario, one can encode a so-called conditional sufficient statistic of the sources instead of jointly encoding multiple sources. We focus on the case where node measurements are in form of noisy linearly mixed combinations of the sources and the acoustic channel mixing matrices are invertible. For this problem, we derive the rate-distortion function for vector Gaussian sources and under covariance distortion constraints.\",\n \"Title: Modelling temporal variations by polynomial regression for classification of radar tracks\\nYear: 2014\\n\\nAbstract: The sampling rate of a radar is often too low to reliably capture the acceleration of moving targets such as birds. Moreover, the sampling rate depends upon the target's acceleration and heading and will therefore generally be time varying. When classifying radar tracks using temporal features, too low or highly varying sampling rates deteriorates the classifier's performance. In this work, we propose to model the temporal variations of the target's speed by low-order polynomial regression. Using the polynomial we obtain the conditional statistics of the targets speed at some future time given its speed at the current time. When used in a classifier based on Gaussian mixture models and with real radar data, it is shown that the inclusions of conditional statistics describing the targets temporal variations, leads to a substantial improvement in the overall classification performance.\",\n \"Title: Perceptual Audio Coding Using N-Channel Lattice Vector Quantization\\nYear: 2006\\n\\nAbstract: We consider the problem of reliable distribution of audio over packet-switched networks. We make use of multiple-description coding combined with transform coding in order to obtain robustness towards packet losses. Previous approaches to this problem were restricted to the case of only two descriptions. In this work we use n-channel multiple-description lattice vector quantizers (MD-LVQs), which allow for the possibility of using more than two descriptions. For a given packet-loss probability we find the number of descriptions and the bit allocation between transform coefficients which minimizes a perceptual distortion measure subject to an entropy constraint. The optimal quantizers are presented in closed form, thus avoiding any iterative quantizer design procedures. The theoretical results are verified with numerical computer simulations using audio signals and it is shown that in environments with excessive packet losses it is advantageous to use more than two descriptions. We verify in subjective listening tests that using more than two descriptions lead to signals of perceptually higher quality\",\n \"Title: Multiple-Description Coding by Dithered Delta–Sigma Quantization\\nYear: 2007\\n\\nAbstract: We address the connection between the multiple-description (MD) problem and Delta-Sigma quanti- zation. The inherent redundancy due to oversampling in Delta-Sigma quantization, and the simple linear- additive noise model resulting from dithered lattice quant ization, allow us to construct a symmetric MD coding scheme. We show that the use of a noise shaping filter ma kes it possible to trade off central distortion for side distortion. Asymptotically as the dime nsion of the lattice vector quantizer and order of the noise shaping filter approach infinity, the entropy rat e of the dithered Delta-Sigma quantization scheme approaches the symmetric two-channel MD rate-distortion function for a memoryless Gaussian source and MSE fidelity criterion, at any side-to-central di stortion ratio and any resolution. In the optimal scheme, the infinite-order noise shaping filter must be minim um phase and have a piece-wise flat power spectrum with a single jump discontinuity. We further show that the optimal noise-shaping filter of any order can be found by solving a set of Yule-Walker equations, and we present an exact rate-distortion analysis for any filter order, lattice vector quantizer dime nsion and bit rate. An important advantage of the proposed design is that it is symmetric in rate by constru ction, and there is therefore no need for source splitting.\",\n \"Title: Low delay moving-horizon multiple-description audio coding forwireless hearing aids\\nYear: 2009\\n\\nAbstract: In this work, we construct a novel scheme for efficient perceptual coding of audio for robust communication between encoders and wireless hearing aids. To limit the physical size of the hearing aids and to reduce power consumption and thereby increase the lifetime expectancy of the batteries, the hearing aids are constrained to be of low complexity. We therefore provide an asymmetric strategy where most of the computational load is placed at the encoding side. We make use of multiple-description coding. This combats possible erasures on the wireless link between the encoder and the hearing aids without introducing significant delay. Furthermore, we employ psychoacoustically optimized noise-shaping quantizers based on the moving-horizon principle, which exploits a finite prediction horizon.\",\n \"Title: Sequential Error Concealment for Video/Images by Weighted Template Matching\\nYear: 2012\\n\\nAbstract: In this paper we propose a novel spatial error concealment algorithm for video and images based on convex optimization. Block-based coding schemes in packet loss environment are considered. Missing macro blocks are sequentially reconstructed by filling them with a weighted set of templates extracted from the available neighbourhood. Moreover, a fast approximation of the optimization method is proposed. The technique produces high quality reconstructions that outperforms the state-of-the-art algorithms both in terms of PSNR and MS-SSIM.\",\n \"Title: Quantized predictive control over erasure channels\\nYear: 2009\\n\\nAbstract: We study a control architecture for linear time-invariant plants which are affected by random disturbances. The distinguishing aspect of the situation at hand is that an unreliable data-rate limited network is placed between controller and the plant input. To achieve robustness with respect to i.i.d. dropouts, the controller transmits data packets containing quantized plant input predictions. These minimize a finite horizon cost function and are provided by an appropriate optimal entropy coded dithered lattice vector quantizer. Within this context, we derive an equivalent noise-shaping model of the closed loop system. This model is employed for the design and analysis of the vector quantizer used by the controller.\",\n \"Title: Packetized predictive control for rate-limited networks via sparse representation\\nYear: 2013\\n\\nAbstract: We study a networked control architecture for linear time-invariant plants in which an unreliable data-rate limited network is placed between the controller and the plant input. The distinguishing aspect of the situation at hand is that an unreliable data-rate limited network is placed between controller and the plant input. To achieve robustness with respect to dropouts, the controller transmits data packets containing plant input predictions, which minimize a finite horizon cost function. In our formulation, we design sparse packets for rate-limited networks, by adopting an an ℓ0 optimization, which can be effectively solved by an orthogonal matching pursuit method. Our formulation ensures asymptotic stability of the control loop in the presence of bounded packet dropouts. Simulation results indicate that the proposed controller provides sparse control packets, thereby giving bit-rate reductions for the case of memoryless scalar coding schemes when compared to the use of, more common, quadratic cost functions, as in linear quadratic (LQ) control.\",\n \"Title: Independent source coding for control over noiseless channels\\nYear: 2010\\n\\nAbstract: By focusing on a class of source coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source coding scheme has to be deployed in the feedback path. We give a closed form expression for the minimal average data-rate required to achieve a given performance level, and also study the interplay between stability and average data-rates for the considered architecture.\",\n \"Title: Multiple Description Coding for Closed Loop Systems over Erasure Channels\\nYear: 2013\\n\\nAbstract: In this paper, we consider robust source coding in closed-loop systems. In particular, we consider a (possibly) unstable LTI system, which is to be stabilized via a network. The network has random delays and erasures on the data-rate limited (digital) forward channel between the encoder (controller) and the decoder (plant). The feedback channel from the decoder to the encoder is assumed noiseless. Since the forward channel is digital, we need to employ quantization. We combine two techniques to enhance the reliability of the system. First, in order to guarantee that the system remains stable during packet dropouts and delays, we transmit quantized control vectors containing current control values for the decoder as well as future predicted control values. Second, we utilize multiple description coding based on forward error correction codes to further aid in the robustness towards packet erasures. In particular, we transmit M redundant packets, which are constructed such that when receiving any J packets, the current control signal as well as J-1 future control signals can be reliably reconstructed at the decoder. We prove stability subject to quantization constraints, random dropouts, and delays by showing that the system can be cast as a Markov jump linear system.\",\n \"Title: Sampling versus random binning for multiple descriptions of a bandlimited source\\nYear: 2013\\n\\nAbstract: Random binning is an efficient, yet complex, coding technique for the symmetric L-description source coding problem. We propose an alternative approach, that uses the quantized samples of a bandlimited source as “descriptions”. By the Nyquist condition, the source can be reconstructed if enough samples are received. We examine a coding scheme that combines sampling and noise-shaped quantization for a scenario in which only K <;L descriptions or all L descriptions are received. Some of the received K-sets of descriptions correspond to uniform sampling while others to non-uniform sampling. This scheme achieves the optimum rate-distortion performance for uniform-sampling K-sets, but suffers noise amplification for nonuniform-sampling K-sets. We then show that by increasing the sampling rate and adding a random-binning stage, the optimal operation point is achieved for any K-set.\",\n \"Title: An Achievable Data-Rate Region Subject to a Stationary Performance Constraint for LTI Plants\\nYear: 2011\\n\\nAbstract: This note studies the performance of control systems subject to average data-rate limits. We focus on a situation where a noisy LTI system has been designed assuming transparent feedback and, due to implementation constraints, a source coding scheme (with unity signal transfer function) has to be deployed in the feedback path. For this situation and by focusing on a specific source coding scheme, we give a closed-form upper bound on the minimal average data-rate that allows one to attain a given performance level. Instrumental to our main result is the explicit solution of a related signal-to-noise ratio minimization problem, subject to a closed loop performance constraint.\",\n \"Title: Packetized Predictive Control of Stochastic Systems Over Bit-Rate Limited Channels With Packet Loss\\nYear: 2011\\n\\nAbstract: We study a control architecture for linear time-invariant plants with random disturbances and where a network is placed between the controller output and the plant input. The network imposes a constraint on the expected bit-rate and is affected by random independent and identically distributed (i.i.d.) dropouts. Dropout-rates and acknowledgments of receipt are not available at the controller side. To achieve robustness with respect to i.i.d. dropouts, the controller transmits data packets containing quantized plant input predictions. These are provided by an appropriate optimal entropy coded dithered lattice vector quantizer. Within this context, we derive stochastic stability results and provide a noise-shaping model of the closed loop system. This model is employed for performance analysis by using rate-distortion theory.\",\n \"Title: Predictive power control for dynamic state estimation over wireless sensor networks with relays\\nYear: 2010\\n\\nAbstract: We present a predictive power controller for state estimation of a stationary ARMA process over a wireless sensor network (WSN), consisting of sensor nodes, relays, and a single gateway (GW). The state estimate is formed centrally at the GW by using packets received from sensors and relays. The latter perform network coding of sensor measurements. Communication from sensors and relays to the GW is over a fading channel. Packet loss probabilities depend upon the time-varying channel gains and the transmission powers used. To achieve an optimal trade-off between state estimation quality and energy expenditure, in our approach the GW decides upon the in general time-varying transmission powers of sensors and relays. This decision process is carried out on-line and adapts to changing channel conditions by using elements of stochastic model predictive control. Simulations on measured channel data illustrate the performance achieved by the proposed controller.\",\n \"Title: Multiple descriptions using sparse decompositions\\nYear: 2010\\n\\nAbstract: In this paper, we consider the design of multiple descriptions (MDs) using sparse decompositions. In a description erasure channel only a subset of the transmitted descriptions is received. The MD problem concerns the design of the descriptions such that they individually approximate the source and furthermore are able to refine each other. In this paper, we form descriptions using convex optimization with l1-norm minimization and Euclidean distortion constraints on the reconstructions and show that with this method we can obtain non-trivial descriptions. We give an algorithm based on recently developed first-order method to the proposed convex problem such that we can solve large-scale instances for image sequences.\",\n \"Title: Rate-distortion in closed-loop LTI systems\\nYear: 2013\\n\\nAbstract: We consider a networked LTI system subject to an average data-rate constraint in the feedback path. We provide upper bounds to the minimal source coding rate required to achieve mean square stability and a desired level of performance. In the quadratic Gaussian case, an almost complete rate-distortion characterization is presented.\",\n \"Title: Shaped Gaussian Dictionaries for Quantized Networked Control Systems With Correlated Dropouts\\nYear: 2016\\n\\nAbstract: This paper studies fixed rate vector quantisation for noisy networked control systems (NCSs) with correlated packet dropouts. In particular, a discrete-time linear time invariant system is to be controlled over an error-prone digital channel. The controller uses (quantized) packetized predictive control to reduce the impact of packet losses. The proposed vector quantizer is based on sparse regression codes (SPARC), which have recently been shown to be efficient in open-loop systems when coding white Gaussian sources. The dictionaries in existing design of SPARCs consist of independent and identically distributed (i.i.d.) Gaussian entries. However, we show that a significant gain can be achieved by using Gaussian dictionaries that are shaped according to the second-order statistics of the NCS in question. Furthermore, to avoid training of the dictionaries, we provide closed-form expressions for the required second-order statistics in the absence of quantization.\",\n \"Title: Reconstruction Algorithms in Undersampled AFM Imaging.\\nYear: 2016\\n\\nAbstract: This paper provides a study of spatial undersampling in atomic force microscopy (AFM) imaging followed by different image reconstruction techniques based on sparse approximation as well as interpolation. The main reasons for using undersampling is that it reduces the path length and thereby the scanning time as well as the amount of interaction between the AFM probe and the specimen. It can easily...\",\n \"Title: Online estimation of wind turbine blade deflection with UWB signals\\nYear: 2015\\n\\nAbstract: In this paper we use ultra-wideband (UWB) signals for the localization of blade tips on wind turbines. Our approach is to acquire two separate distances to each tip via time-delay estimation, and each tip is then localized by triangulation. We derive an approximate maximiun a posteriori (MAP) delay estimator exploiting i) contextual prior information and ii) direct-path approximation. The resulting deflection estimation algorithm is computationally feasible for online usage. Simulation studies are conducted to assess the overall triangulation uncertainty and it is observed that negative correlation between the two distance estimates is detrimental for the tip localization accuracy. Measurement data acquired in an anechoic chamber is used to confirm that the UWB-hardware complies with the desired/relevant ranging accuracy. Finally, measurement data obtained from a static test bench is used to demonstrate that the approximate MAP-based localization algorithm is able to outperform standard methods.\",\n \"Title: Predicting reconstruction quality within compressive sensing for atomic force microscopy\\nYear: 2015\\n\\nAbstract: With compressive sensing, the obtainable reconstruction quality depends on the original signal, the reconstruction algorithm, the measurement matrix, and the dictionary matrix. The present paper is concerned with establishing performance indicators and using these to predict reconstruction quality in atomic force microscopy applications. For this purpose, we consider the well-known quantities of coherence and mutual coherence. Furthermore, we propose a new performance indicator derived from coherence in order to better model the average reconstruction quality. Through extensive simulations, affine models using the performance indicators are evaluated in terms of modified coefficients of determination. The results show that the proposed performance indicator yields a better model than both coherence and mutual coherence do. In conclusion, the proposed performance indicator can be used to predict reconstruction quality for the given application, and the affine prediction model can be improved by including coherence and mutual coherence.\",\n \"Title: Multiple descriptions for packetized predictive control.\\nYear: 2016\\n\\nAbstract: In this paper, we propose to use multiple descriptions (MDs) to achieve a high degree of robustness towards random packet delays and erasures in networked control systems. In particular, we consider the scenario, where a data-rate limited channel is located between the controller and the plant input. This forward channel also introduces random delays and dropouts. The feedback channel from the plant output to the controller is assumed noiseless. We show how to design MDs for packetized predicted control (PPC) in order to enhance the robustness. In the proposed scheme, a quantized control vector with future tentative control signals is transmitted to the plant at each discrete time instant. This control vector is then transformed into M redundant descriptions (packets) such that when receiving any 1≤J≤M packets, the current control signal as well as J−1 future control signals can be reliably reconstructed at the plant side. For the particular case of LTI plant models and i.i.d. channels, we show that the overall system forms a Markov jump linear system. We provide conditions for mean square stability and derive upper bounds on the operational bit rate of the quantizer to guarantee a desired performance level. Simulations reveal that a significant gain over conventional PPC can be achieved when combining PPC with suitably designed MDs.\",\n \"Title: Discrete-time hands-off control by sparse optimization.\\nYear: 2016\\n\\nAbstract: Maximum hands-off control is a control mechanism that maximizes the length of the time duration on which the control is exactly zero. Such a control is important for energy-aware control applications, since it can stop actuators for a long duration and hence the control system needs much less fuel or electric power. In this article, we formulate the maximum hands-off control for linear discrete-time plants by sparse optimization based on the l 1 norm. For this optimization problem, we derive an efficient algorithm based on the alternating direction method of multipliers (ADMM). We also give a model predictive control formulation, which leads to a robust control system based on a state feedback mechanism. Simulation results are included to illustrate the effectiveness of the proposed control method.\",\n \"Title: A recursive kinematic random forest and alpha beta filter classifier for 2D radar tracks.\\nYear: 2016\\n\\nAbstract: In this work, we show that by using a recursive random forest together with an alpha beta filter classifier, it is possible to classify radar tracks from the tracks’ kinematic data. The kinematic data is from a 2D scanning radar without Doppler or height information. We use random forest as this classifier implicitly handles the uncertainty in the position measurements. As stationary targets can have an apparently high speed because of the measurement uncertainty, we use an alpha beta filter classifier to classify stationary targets from moving targets. We show an overall classification rate from simulated data at 82.6 % and from real-world data at 79.7 %. Additional to the confusion matrix, we also show recordings of real-world data.\",\n \"Title: Delay Minimization in Real-time Communications with Joint Buffering and Coding.\\nYear: 2017\\n\\nAbstract: We present a closed-form expression for the minimal delay that is achievable in a setting that combines a buffer and an erasure code, used to mitigate the packet delay variance. The erasure code is modeled according to the recent information-theoretic results on finite block length codes. Evaluations reveal that accurate knowledge of the network parameters is essential for optimal operation. Moreover, it is shown that, when the network packet delay variance is large, the buffer delay becomes negligible. Therefore, in this case, the delay budget should be spent mainly on the erasure code.\",\n \"Title: Source Coding in Networks With Covariance Distortion Constraints.\\nYear: 2016\\n\\nAbstract: We consider a source coding problem with a network scenario in mind, and formulate it as a remote vector Gaussian Wyner-Ziv problem under covariance matrix distortions. We define a notion of minimum for two positive-definite matrices based on which we derive an explicit formula for the rate-distortion function. We then study the special cases and applications of this result. We show that two well-...\",\n \"Title: Interplay Between Transmission Delay, Average Data Rate, And Performance In Output Feedback Control Over Digital Communication Channels\\nYear: 2017\\n\\nAbstract: The performance of a noisy linear time-invariant (LTI) plant, controlled over a noiseless digital channel with transmission delay, is investigated in this paper. The rate limited channel connects the single measurement output of the plant to its single control input through a causal, but otherwise arbitrary, coder-controller pair. An information theoretic approach is utilized to analyze the minimal average data rate required to attain the quadratic performance when the channel imposes a known constant delay on the transmitted data. This infimum average data rate is shown to be lower bounded by minimizing the directed information rate across a set of LTI filters and an additive white Gaussian noise (AWGN) channel. It is demonstrated that the presence of time delay in the channel increases the data rate needed to achieve a certain level of performance. The applicability of the results is verified through a numerical example.\",\n \"Title: Zero-Delay Rate Distortion via Filtering for Unstable Vector Gaussian Sources.\\nYear: 2017\\n\\nAbstract: In this work, we deal with zero-delay source coding of an unstable vector Gaussian Auto-Regressive (AR) source under average mean square error fidelity criterion. To begin with, we consider zero-delay coding of a vector Gaussian AR(1) source modeled in state space form. It turns out to be convenient to use an asymptotically stationary time-domain scheme with feedback, which was recently proposed in [1] in the context of filtering theory applications via the Information Nonanticipative Rate Distortion Function (INRDF). In this scheme, the feedback path comprises a Kalman filter, which produces an estimate of the source. Our idea is then to encode the vector innovations due to Kalman filtering via lattice quantization with subtractive dither and memoryless entropy coding. We show that the resulting system is stable and furthermore provide new bounds to the zero-delay RDF. We then generalize our results to vector Gaussian AR sources of any order. With this, we are able to establish a time-domain approach with feedback, which by use of a single filter gets very close to the zero-delay RDF for vector Gaussian AR sources of any order. Interestingly, for infinite dimensional vector sources, the INRDF coincides with the Optimal Performance Theoretically Attainable (OPTA) by zero-delay codes.\",\n \"Title: On Perceptual Audio Compression with Side Information at the Decoder\\nYear: 2016\\n\\nAbstract: Due to the distributed structure of many modern audio transmission setups, it is likely to have an observation at the receiver which is correlated with the desired source at the transmitter. This observation could be used as side information to reduce the transmission rate using distributed source coding. How to integrate distributed source coding into the perceptual audio compression procedure is thus a fundamental question. In this paper, we take a completely analytical approach to this problem, in particular to the rate-distortion trade-off and the corresponding coding schemes. We then interpret the results from an audio coding perspective. The main result is that, to upgrade a regular perceptual audio coder to a distributed coder, one needs to revise the perceptual masking curve. The revised masking curve models the availability of the side information as an extra masking effect, yielding lower rates. Interestingly, this means that at least conceptually, the distributed coding scenario could be integrated into the audio coder with minor changes, and without destructing the original coder.\",\n \"Title: An Asymmetric Difference Multiple Description Gaussian Noise Channel\\nYear: 2017\\n\\nAbstract: Ozarow's test channel for the quadratic Gaussian (QG) multiple description (MD) problem consists of two correlated AWGN channels. It is known that simply replacing the AWGN channels by quantizers with equivalent statistical properties as the channels, will generally not lead to a rate-distortion optimal realization of the MD rate-distortion function. We have previously proposed a symmetric two-channel model for the QG MD problem for the case, where the two noise terms have equal variances. We show in this paper, that by replacing the AWGN channels of this model by quantizers that are statistical equivalent to the channels, will under high-resolution assumption be rate-distortion optimal. We furthermore extend this symmetric two-channel model to the asymmetric case, and provide a simple suboptimal implementation of the channel based on scalar quantizers. Simulations are provided to show the performance of the proposed implementation.\",\n \"Title: Detection of spoken words in noise: Comparison of human performance to maximum likelihood detection\\nYear: 2016\\n\\nAbstract: In this work, we are interested in assessing the optimality of the human auditory system, when the input stimuli is natural speech that is affected by additive noise. In order to do this, we consider the DANTALE II listening test paradigm of Wagener et al., which has been used to evaluate the intelligibility of noisy speech by exposing human listeners to a selection of constructed noisy sentences. Inspired by this test, we propose a simple model for the communication and classification of noisy speech that takes place in the test. We then identify a number of key properties that the test subjects satisfy, and combine these with our proposed model in order to derive optimal classifiers in the sense of maximum a posteriori estimation. We finally compare the performance of the classifiers to that of humans on the same noisy test sentences. The results reveal that at low SNRs, the human performance is inferior to that of the optimal classifiers. We conclude that in this special task, the human auditory system is not optimal.\",\n \"Title: Superregular Lower Triangular Toeplitz Matrices for Low Delay Wireless Streaming.\\nYear: 2017\\n\\nAbstract: A matrix is termed superregular if all of its possible submatrices are non-singular. Superregular lower triangular Toeplitz matrices are useful for MDS convolutional codes and (sequential) network codes. In this paper, we present the explicit matrix constructions for superregular lower triangular Toeplitz matrices in GF(2p)k×k, k ≤ 5. For k > 5 we provide a greedy algorithm, which (over sufficient...\",\n \"Title: Humans Do Not Maximize The Probability Of Correct Decision When Recognizing Dantale Words In Noise\\nYear: 2017\\n\\nAbstract: Inspired by the DANTALE II listening test paradigm, which is used for determining the intelligibility of noisy speech, we assess the hypothesis that humans maximize the probability of correct decision when recognizing words contaminated by additive Gaussian. speech-shaped noise. We first propose a statistical Gaussian communication and classification scenario, where word models are built from short term spectra of human speech, and optimal classifiers in the sense of maximum a posteriori estimation are derived. Then, we perform a listening test, where the participants are instructed to make their best guess of words contaminated with speech-shaped Gaussian noise. Comparing the human's performance to that of the optimal classifier reveals that at high SNR. humans perform comparable to the optimal classifier. However, at low SNR, the human performance is inferior to that of the optimal classifier. This shows that, at least in this specialized task, humans are generally not able to maximize the probability of correct decision, when recognizing words.\",\n \"Title: Achievable Performance Of Zero-Delay Variable-Rate Coding In Rate-Constrained Networked Control Systems With Channel Delay\\nYear: 2017\\n\\nAbstract: This paper presents an upper bound on the minimum data rate required to achieve a prescribed closed-loop performance level in networked control systems (NCSs). The considered feedback loop includes a linear time-invariant (LTI) plant with single measurement output and single control input. Moreover, in this NCS, a causal but otherwise unconstrained feedback system carries out zero-delay variable-rate coding, and control. Between the encoder and decoder, data is exchanged over a rate-limited noiseless digital channel with a known constant time delay. Here we propose a linear source-coding scheme that with the use of entropy-coded dithered quantizers (ECDQs), attains each quadratic performance level with a rate that exceeds the lower bound in [1] by at most (approximately) 1.254 bits per sample. The upper bound obtained by ECDQ is demonstrated, via simulations, to be an increasing function of the channel time delay at any given performance. In other words, attaining a specific performance level necessitates achieving a higher data rate when the channel time delay grows. The theoretical framework is demonstrated via an illustrative example.\",\n \"Title: Stationarity in the Realizations of the Causal Rate-Distortion Function for One-Sided Stationary Sources.\\nYear: 2018\\n\\nAbstract: This paper derives novel results on the characterization of the the causal information rate-distortion function (IRDF) $R_{c}^{it}(D)$ for arbitrarily-distributed one-sided stationary $kappa$-th order Markov source x(1),x(2),.... It is first shown that Gorbunov and Pinskeru0027s results on the stationarity of the realizations to the causal IRDF (stated for two-sided stationary sources) do not apply to the commonly used family of asymptotic average single-letter (AASL) distortion criteria. Moreover, we show that, in general, a reconstruction sequence cannot be both jointly stationary with a one-sided stationary source sequence and causally related to it. This implies that, in general, the causal IRDF for one-sided stationary sources cannot be realized by a stationary distribution. However, we prove that for an arbitrarily distributed one-sided stationary source and a large class of distortion criteria (including AASL), the search for $R_{c}^{it}(D)$ can be restricted to distributions which yield the output sequence y(1), y(2),... jointly stationary with the source after $kappa$ samples. Finally, we improve the definition of the stationary causal IRDF $overline{R}_{c}^{it}(D)$ previously introduced by Derpich and {O}stergaard for two-sided Markovian stationary sources and show that $overline{R}_{c}^{it}(D)$ for a two-sided source ...,x(-1),x(0),x(1),... equals $R_{c}^{it}(D)$ for the associated one-sided source x(1), x(2),.... This implies that, for the Gaussian quadratic case, the practical zero-delay encoder-decoder pairs proposed by Derpich and {O}stergaard for approaching $R_{c}^{it}(D)$ achieve an operational data rate which exceeds $R_{c}^{it}(D)$ by less than $1+0.5 log_2(2 pi e /12) simeq 1.254$ bits per sample.\",\n \"Title: Estimation of the second heart sound split using windowed sinusoidal models.\\nYear: 2018\\n\\nAbstract: •A2 and P2 are modeled as windowed sinusoids and their sum forms the S2 signal.•S2 split is estimated by cross-correlating the measured S2 and the modeled A2/P2.•RMSE of 7.6 ms for synthetic S2 signals with S2 split swept from −70 to 70 ms.•Results from 146 PCG recordings show an average S2 split of 29.6 ms.\",\n \"Title: Fixed-Rate Zero-Delay Source Coding for Stationary Vector-Valued Gauss-Markov Sources\\nYear: 2018\\n\\nAbstract: We consider a fixed-rate zero-delay source coding problem where a stationary vector-valued Gauss-Markov source is compressed subject to an average mean-squared error (MSE) distortion constraint. We address the problem by considering the Gaussian nonanticipative rate distortion function (NRDF) which is a lower bound to the zero-delay Gaussian RDF. Then, we use its corresponding optimal “test-channel” to characterize the stationary Gaussian NRDF and evaluate the corresponding information rates. We show that the Gaussian NRDF can be achieved by p-parallel fixed-rate scalar uniform quantizers of finite support with dithering signal up to a multiplicative distortion factor and a constant rate penalty. We demonstrate our framework with a numerical example.\",\n \"Title: On Superregular Matrices and Convolutional Codes with Finite Decoder Memory\\nYear: 2018\\n\\nAbstract: In this paper, we present explicit code constructions for a family of (n,k,δ) convolutional codes with optimum distance profiles. The family of convolutional codes is obtained from sets of jointly superregular matrices. For the case of finite decoder memory, we evaluate the performance of the constructed codes in terms of both symbol loss probability and symbol delay. We then present a combinatorial method to calculate the exact symbol loss probability and symbol delay for each symbol individually. We compare the symbol loss probability for two specific systematic convolutional codes for the cases where the sink has infinite or finite memory. Finally, we compare the performance of our convolutional codes with optimum distance profile and random based convolutional codes.\",\n \"Title: Sequential Use of Block Codes and Convolutional Codes in a Real-Time Multi-Hop Network\\nYear: 2018\\n\\nAbstract: Real-time streaming of audio and video have tight constraints on the delay allowed at each step in the distribution chain. In this paper, we focus on the transport layer. That is, we investigate the effect of imposing a maximum allowable delay on the symbol loss probability for a set of rate 1/2 erasure correcting codes. We define the effective symbol loss probability to be the probability that a symbol is received too late or not at all, given some maximum allowable delay. We consider networks where the source and sink communicate via a relaying node, and that this intermediate node performs recoding. The erasure correcting code used between the source and relay need not be the same as the erasure correcting code used between the relay and sink. Moreover, on the first link, we use both a block code and on the second link we use a convolutional code. In order to do a fair comparison, we also include the case where both links use the same code type. Our results show that in order to minimize the effective symbol loss, the first link should use a triangular block code. Whereas, the second link should use a convolutional or triangular code, with little to no gain of using the former over the latter.\",\n \"Title: The Effect of Time Delay on the Average Data Rate and Performance in Networked Control Systems\\nYear: 2018\\n\\nAbstract: This article studies the performance of a feedback control loop closed via an error-free digital communication channel with transmission delay. The system comprises a discrete-time noisy linear time-invariant plant, whose single measurement output is mapped into its single control input by a causal, but otherwise arbitrary, coding and control scheme. We consider a single-input multiple-output chan...\",\n \"Title: Zero-Delay Rate Distortion via Filtering for Vector-Valued Gaussian Sources.\\nYear: 2018\\n\\nAbstract: We deal with zero-delay source coding of a vector-valued Gauss-Markov source subject to a mean-squared error (MSE) fidelity criterion characterized by the operational zero-delay vector-valued Gaussian rate distortion function (RDF). We address this problem by considering the nonanticipative RDF (NRDF), which is a lower bound to the causal optimal performance theoretically attainable function (or s...\",\n \"Title: On Zero-Delay Source Coding Of Lti Gauss-Markov Systems With Covariance Matrix Distortion Constraints\\nYear: 2018\\n\\nAbstract: We introduce a new class of zero-delay source coding problems where a vector-valued Gauss-Markov source is conveyed subject to covariance matrix distortion constraints. We address this problem by defining an information theoretic measure where we minimize mutual information subject to causality constraints and covariance matrix distortion constraints. The resulting measure serves as a lower bound to the zero-delay rate distortion function (RDF). We solve this problem by showing that it is semidefinite representable and, thus, can be computed numerically. We also show that for this new class of information measures, it is possible to have achievable rates up to a constant space-filling loss due to a vector lattice quantizer and a constant loss due to entropy coding. We corroborate our framework with illustrative simulation examples.\",\n \"Title: Mean square performance evaluation in frequency domain for an improved adaptive feedback cancellation in hearing aids.\\nYear: 2019\\n\\nAbstract: •Analyzing dependence of system-behaviour of LP-based adaptive feedback canceller with and without probe noise, on adaptive algorithm employed.•For unbiased feedback cancellation using LP-based feedback canceller with shaped probe noise, steady-state error is increased for RLS algorithm.•For NLMS algorithm, cost of unbiased feedback estimate is reduction in rate of convergence, along with an increase in the tracking error.•Loudspeaker output of LP-based feedback canceller with shaped probe noise shows less distortion and whistling problem.•Derived expressions provide accurate approximation of power transfer function, convergence rate and steady-state error for different inputs.\",\n \"Title: Sound Quality Improvement for Hearing Aids in Presence of Multiple Inputs\\nYear: 2019\\n\\nAbstract: AbstractModern-day hearing aids are capable of receiving acoustic signals over a wireless link and also from the surroundings through the microphone. If the hearing aid receives input only from the acoustic environment, feedback cancellation proceeds according to the existing methodologies for bias reduction. However, the wirelessly received signal and the acoustic environment input, when emitted from the same source, can be very similar to each other or with a time-delayed version of each other, thereby having a high correlation between them. Both inputs can also be emitted from different sources and, thus, be less correlated with each other. In the aforementioned scenarios, acoustic confusion can occur for the user as the hearing aid receives both signals simultaneously. To improve the output signal quality and to reduce bias in an adaptive feedback cancellation system with a wirelessly received signal as well as an acoustic environment input, we propose a cost function, and the optimization of the feed-forward path and of the shaping filter for the wireless signal. The feed-forward path is designed to be a cascade of the required acoustic enhancement along with an FIR filter. We derive expressions for an optimum shaping filter and for an optimized feed-forward path. Improvement in loudspeaker output signal quality, normalized misalignment and maximum stable gain for each of the above-mentioned scenarios is assessed through numerical simulations.\",\n \"Title: The Entropy Gain Of Linear Systems And Some Of Its Implications\\nYear: 2021\\n\\nAbstract: We study the increase in per-sample differential entropy rate of random sequences and processes after being passed through a non minimum-phase (NMP) discrete-time, linear time-invariant (LTI) filter G. For LTI discrete-time filters and random processes, it has long been established by Theorem 14 in Shannon's seminal paper that this entropy gain, G(G), equals the integral of log|G(e(j omega))|. In this note, we first show that Shannon's Theorem 14 does not hold in general. Then, we prove that, when comparing the input differential entropy to that of the entire (longer) output of G, the entropy gain equals G(G). We show that the entropy gain between equal-length input and output sequences is upper bounded by G(G) and arises if and only if there exists an output additive disturbance with finite differential entropy (no matter how small) or a random initial state. Unlike what happens with linear maps, the entropy gain in this case depends on the distribution of all the signals involved. We illustrate some of the consequences of these results by presenting their implications in three different problems. Specifically: conditions for equality in an information inequality of importance in networked control problems; extending to a much broader class of sources the existing results on the rate-distortion function for non-stationary Gaussian sources, and an observation on the capacity of auto-regressive Gaussian channels with feedback.\",\n \"Title: Joint Far- and Near-End Speech Intelligibility Enhancement Based on the Approximated Speech Intelligibility Index\\nYear: 2022\\n\\nAbstract: This paper considers speech enhancement of signals picked up in one noisy environment which must be presented to a listener in another noisy environment. Recently, it has been shown that an optimal solution to this problem requires the consideration of the noise sources in both environments jointly. However, the existing optimal mutual information based method requires a complicated system model that includes natural speech variations, and relies on approximations and assumptions of the underlying signal distributions. In this paper, we propose to use a simpler signal model and optimize speech intelligibility based on the Approximated Speech Intelligibility Index (ASII). We derive a closed-form solution to the joint far- and near-end speech enhancement problem that is independent of the marginal distribution of signal coefficients, and that achieves similar performance to existing work. In addition, we do not need to model or optimize for natural speech variations.\",\n \"Title: Compression of DNNs Using Magnitude Pruning and Nonlinear Information Bottleneck Training\\nYear: 2021\\n\\nAbstract: As Deep Neural Networks (DNNs) have achieved state-of-the-art performance in various scientific fields and applications, the memory and computational complexity of DNNs have increased concurrently. The increased complexity required by DNNs prohibits them from running on platforms with limited computational resources. This has sparked a renewed interest in parameter pruning. We propose to replace t...\",\n \"Title: A Family of Adaptive Volterra Filters Based on Maximum Correntropy Criterion for Improved Active Control of Impulsive Noise\\nYear: 2022\\n\\nAbstract: Linear active noise control (ANC) systems have been used in the past to effectively suppress Gaussian noise. A practical ANC system must consider nonlinearities in the secondary path with a non-minimum phase. For an ANC system to effectively operate in a modern-day acoustic environment with multiple electrical/electronic systems operating in the vicinity, the reference noise source is taken as a non-Gaussian stochastic process. Linear systems have shown unacceptable performance in countering the disturbances that are impulsive in nature. Considering these issues, we propose a family of adaptive algorithms for ANC systems that employ a second-order Volterra filter for accurate modeling of the impulsive disturbances. We utilize the maximum correntropy criterion as the cost function to improve the adaptive filtering process, which generates the most appropriate output signal in the ANC system's successive iterative stages. The proposed algorithms feature dynamic learning-rate parameters, which improve the tracking performance of the algorithms. Also, a careful selection of the Volterra filter's kernel size in the proposed algorithms ensures a balance between system stability and convergence rate. These parameters are made automatically adjustable, based on the residual error and the reference input signals, to optimize performance in non-Gaussian environments. A comparison of the proposed algorithms with its counterparts is presented through computer simulations in terms of average noise reduction for different levels of impulsive noise. The proposed algorithms are also compared with each other to find the best performing algorithm in a non-Gaussian environment. Achieved results exhibit the effectiveness of the proposed algorithms in their ability to attenuate impulsive noise in comparison with the existing adaptive algorithms for ANC systems. Later, the proposed algorithm has been implemented for speech enhancement, where the noise from the speech sample is identified and removed using an adaptive filter algorithm. Simulations reveal that the devised algorithm can effectively denoise speech signals. Further, in the last part of the paper, the VF-MCCRMC is modified in accordance with the energy of the error signal, and the simulation results demonstrated the improvement in stability and error performance.\",\n \"Title: Correction to “A Framework for Control System Design Subject to Average Data-Rate Constraints”\\nYear: 2022\\n\\nAbstract: Theorem 4.1 in the 2011 paper “A Framework for Control System Design Subject to Average Data-Rate Constraints” allows one to lower bound average operational data rates in feedback loops (including the situation in which encoder and decoder have side information). Unfortunately, its proof is invalid. In this note, we first state the theorem and explain why its proof is flawed, and then provide a correct proof under weaker assumptions.\",\n \"Title: Model-Based Estimation of in-Car-Communication Feedback Applied to Speech Zone Detection\\nYear: 2022\\n\\nAbstract: Modern cars provide versatile tools to enhance speech communication. While an in-car communication (ICC) system aims at enhancing communication between the passengers by playing back desired speech via loudspeakers in the car, these loudspeaker signals may disturb a speech enhancement system required for hands-free telephony and automatic speech recognition. In this paper, we focus on speech zone detection, i.e. detecting which passenger in the car is speaking, which is a crucial component of the speech enhancement system. We propose a model-based feedback estimation method to improve robustness of speech zone detection against ICC feedback. Specifically, since the zone detection system typically does not have access to the ICC loudspeaker signals, the proposed method estimates the feedback signal from the observed microphone signals based on a free-field propagation model between the loudspeakers and the microphones as well as the ICC gain. We propose an efficient recursive implementation in the short-time Fourier transform domain using convolutive transfer functions. A realistic simulation study indicates that the proposed method allows to increase the ICC gain by about 6 dB while still achieving robust speech zone detection results.\",\n \"Title: A Linear MMSE Filter Using Delayed Remote Microphone Signals for Speech Enhancement in Hearing Aid Applications\\nYear: 2022\\n\\nAbstract: Existing methods that use remote microphones with hearing aid (HA) noise reduction systems, assume the wireless transmission to be instantaneous. In practice, however, there exists a time difference of arrival (TDOA) between the wirelessly transmitted target signals and the acoustic signal arriving from the target source to the HA device, which degrades their noise reduction performance. As speech is correlated between consecutive time-frames in the short-time Fourier transform (STFT) domain, we propose a linear minimum mean-square error (MMSE) estimator to estimate the desired signal, by combining multiple HA microphone signals with multiple consecutive time-frames of the remote microphone signal. We derive closed form expressions for the resulting filter weights and interpret them in terms of existing multi-channel and multi-frame methods. The simulation results validate the interpretation and show that using a multi-frame method along with a multi-channel method is an advantage, in the presence of unknown, positive TDOA between the microphone signals.\"\n]","isConversational":false},"profile_size":{"kind":"number","value":88,"string":"88"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13381,"string":"13,381"}}},{"rowIdx":13382,"cells":{"question_id":{"kind":"string","value":"Edward A Fox"},"question":{"kind":"string","value":"Generate an abstract for the title \"Ensemble: a distributed portal for the distributed community of computing education\" using the following items: NSDL, Ensemble, computing, education, resources"},"answer":{"kind":"string","value":"NSF's NSDL is composed of domain-oriented pathways. Ensemble is the pathway for computing and supports the full range of computing education communities, providing a base for the development of programs that blend computing with other STEM areas (e.g., X-informatics and Computing + X), and producing digital library innovations that can be propagated to other NSDL pathways. Computing is a distributed community, including computer science, computer engineering, software engineering, information science, information systems, and information technology. Ensemble aims to provide much needed support for the many distinct yet overlapping educational programs in computing and their associated communities. To do this, Ensemble takes the form of a distributed portal providing access to the broad range of existing educational resources while preserving the collections and their associated curatorial processes. Ensemble encourages contribution, use, reuse, review, and evaluation of educational materials at multiple levels of granularity."},"correct_answer":{"kind":"string","value":"NSF's NSDL is composed of domain-oriented pathways. Ensemble is the pathway for computing and supports the full range of computing education communities, providing a base for the development of programs that blend computing with other STEM areas (e.g., X-informatics and Computing + X), and producing digital library innovations that can be propagated to other NSDL pathways. Computing is a distributed community, including computer science, computer engineering, software engineering, information science, information systems, and information technology. Ensemble aims to provide much needed support for the many distinct yet overlapping educational programs in computing and their associated communities. To do this, Ensemble takes the form of a distributed portal providing access to the broad range of existing educational resources while preserving the collections and their associated curatorial processes. Ensemble encourages contribution, use, reuse, review, and evaluation of educational materials at multiple levels of granularity."},"documents":{"kind":"list like","value":["Title: Introduction to digital libraries\nYear: 2016\n\nAbstract: This tutorial is a thorough and deep introduction to the DL field, providing a firm foundation: covering key concepts and terminology, as well as services, systems, technologies, methods, standards, projects, issues, and practices. It introduces and builds upon a firm theoretical foundation (starting with the '5S' set of intuitive aspects: Streams, Structures, Spaces, Scenarios, Societies), giving careful definitions and explanations of all the key parts of a 'minimal digital library', and expanding from that basis to cover key DL issues. Illustrations come from a set of case studies. Attendees will be exposed to four Morgan & Claypool books that elaborate on 5S, 2012-2014. Complementing the coverage of '5S' will be an overview of key aspects of the DELOS Reference Model and DL.org activities. Further, use of a Hadoop cluster supporting DLs will be described.","Title: What if there were desktop access to the computer science literature?\nYear: 1993\n\nAbstract: What if there were an electronic computer science library? Consider the possibilities of having your favorite publications available within finger's reach. Consider Project Envision, an ongoing effort to build a user-centered database from the computer science literature. This paper describes the project's first year progress, stressing the underlying motivation, user-centered development, and the overall design.","Title: Overview of digital libraries\nYear: 2002\n\nAbstract: This tutorial will start with an overview of definitions, foundations, scenarios, and perspectives. It will cover a variety of issues, including search, retrieval, and resource discovery; multimedia/hypermedia; metadata (e.g., Dublin Core); electronic publishing; document models and representations; SGML and XML; database approaches; agents and distributed processing; 2D and 3D interfaces and visualizations; metrics; architectures and interoperability; educational and social concerns; commerce and intellectual property rights, among others.","Title: Using CITIDEL to develop and share class plans\nYear: 2004\n\nAbstract: This demonstration will illustrate the use of existing and proposed tools in CITIDEL for finding existing resources to integrate into a course and for developing well structured descriptions of class and laboratory activities for sharing with the computing community.","Title: Removal policies in network caches for World-Wide Web documents\nYear: 1996\n\nAbstract: World-Wide Web proxy servers that cache documents can potentially reduce three quantities: the number of requests that reach popular servers, the volume of network traffic resulting from document requests, and the latency that an end-user experiences in retrieving a document. This paper examines the first two using the measures of cache hit rate and weighted hit rate (or fraction of client-requested bytes returned by the proxy). A client request for an uncached document may cause the removal of one or more cached documents. Variable document sizes and types allow a rich variety of policies to select a document for removal, in contrast to policies for CPU caches or demand paging, that manage homogeneous objects. We present a taxonomy of removal policies. Through trace-driven simulation, we determine the maximum possible hit rate and weighted hit rate that a cache could ever achieve, and the removal policy that maximizes hit rate and weighted hit rate. The experiments use five traces of 37 to 185 days of client URL requests. Surprisingly, the criteria used by several proxy-server removal policies (LRU, Hyper-G, and a proposal by Pitkow and Recker) are among the worst performing criteria in our simulation; instead, replacing documents based on size maximizes hit rate in each of the studied workloads.","Title: Using concept maps as a cross-language resource discovery tool for large documents in digital libraries\nYear: 2005\n\nAbstract: Project Gutenburg, the Million Book Project, the Networked Digital Library of Theses and Dissertations, Amazon's book search service, and the recently announced collaboration of Google and leading libraries, all aim to make available large numbers of book-length objects, in a variety of languages. Traditional approaches to discovering a suitable book for a particular purpose have generally relied on catalog records, sometimes enhanced with abstracts. Full-text searching - popular, e.g., with legal and government documents $and passage retrieval techniques, suitable for encyclopedias and reference works, have not been adequately tested with large collections of large objects","Title: Use of subimages in fish species identification: a qualitative study\nYear: 2011\n\nAbstract: Many scholarly tasks involve working with subdocuments, or contextualized fine-grain information, i.e., with information that is part of some larger unit. A digital library (DL) facilitates management, access, retrieval, and use of collections of data and metadata through services. However, most DLs do not provide infrastructure or services to support working with subdocuments. Superimposed information (SI) refers to new information that is created to reference subdocuments in existing information resources. We combine this idea of SI with traditional DL services, to define and develop a DL with SI (SI-DL). We explored the use of subimages and evaluated the use of SuperIDR, a prototype SI-DL, in fish species identification, a scholarly task that involves working with subimages. The contexts and strategies of working with subimages in SuperIDR suggest new and enhanced support (SI-DL services) for scholarly tasks that involve working with subimages, including new ways of querying and searching for subimages and associated information. The main conceptual contributions of our work are the insights gained from these findings of the use of subimages and of SuperIDR, which lead to recommendations for the design of digital libraries with superimposed information.","Title: NMFS: Network Multimedia File System Protocol\nYear: 1992\n\nAbstract: We describe an on-going project to develop a Network Multimedia File System (NMFS) protocol. The protocol allows \"transparent access of shared files across networks\" as Sun''s NFS protocol does, but attempts to meet a real-time delivery schedule. NMFS is designed to provide ubiquitous service over networks both designed and not designed to carry multimedia traffic.","Title: The role of digital libraries in moving toward knowledge environments\nYear: 2005\n\nAbstract: For thousands of years, libraries have allowed humanity to collect and organize data and information, and to support the discovery and communication of knowledge, across time and space. Coming together in this Internet Age, the world's societies have extended this process to span from the personal to the global, as the concepts, practices, systems, and services related to Library and Information Science unfold through digital libraries. Scientists, scholars, teachers, learners, and practitioners of all kinds benefit from the distributed and collaborative knowledge environments that are at the heart of the digital library movement. Digital libraries thus encompass the dimensions in the 5S Framework: Societies, Scenarios, Spaces, Streams, and Structures. To clarify this approach, we explain the role of meta-models, such as of a minimal digital library (DL), and of more specialized (discipline-oriented) DLs, such as archeological DLs. We illustrate how suitable knowledge environments can be more easily prepared as instances of these meta-models, resulting in usable and useful DLs, including for education, computing, and archaeology.","Title: Knowledge discovery in digital libraries of electronic theses and dissertations: an NDLTD case study\nYear: 2008\n\nAbstract: Many scholarly writings today are available in electronic formats. With universities around the world choosing to make digital versions of their dissertations, theses, project reports, and related files and data sets available online, an overwhelming amount of information is becoming available on almost any particular topic. How will users decide which dissertation, or subsection of a dissertation, to read to get the required information on a particular topic? What kind of services can such digital libraries provide to make knowledge discovery easier? In this paper, we investigate these issues, using as a case study the Networked Digital Library of Theses and Dissertations (NDLTD), a rapidly growing collection that already has about 800,000 Electronic Theses and Dissertations (ETDs) from universities around the world. We propose the design for a scalable, Web Services based tool KDWebS (Knowledge Discovery System based on Web Services), to facilitate automated knowledge discovery in NDLTD. We also provide some preliminary proof of concept results to demonstrate the efficacy of the approach.","Title: Effectiveness of implicit rating data on characterizing users in complex information systems\nYear: 2005\n\nAbstract: Most user focused data mining techniques involve purchase pattern analysis, targeted at strictly-formatted database-like transaction records. Most personalization systems employ explicitly provided user preferences rather than implicit rating data obtained automatically by collecting users' interactions. In this paper, we show that in complex information systems such as digital libraries, implicit rating data can help to characterize users' research and learning interests, and can be used to cluster users into meaningful groups. Thus, in our personalized recommender system based on collaborative filtering, we employ a user tracking system and a user modeling technique to capture and store users' implicit ratings. Also, we describe the effects (on community finding) of using four different types of implicit rating data.","Title: Mirroring an OAI archive on the I2-DSI channel\nYear: 2002\n\nAbstract: The Open Archives Initiative (OAI) promotes interoperability among digital libraries and has created a protocol for data providers to easily export their metadata. One problem with this approach is that some of the more popular servers quickly become heavily loaded. The obvious solution is replication. Fortunately, the Internet-2 Distributed Storage Infrastructure (I2-DSI) has begun to develop technology for highly distributed transparent replication of servers. This paper presents our solution for transparent mirroring of OAI repositories within the I2-DSI.","Title: ETANA-DL: a digital library for integrated handling of heterogeneous archaeological data\nYear: 2004\n\nAbstract: Archaeologists have to deal with vast quantities of information, generated both in the field and laboratory. That information is heterogeneous in nature, and different projects have their own systems to store and use it. This adds to the challenges regarding collaborative research between such projects as well as information retrieval for other more general purposes. This paper describes our approach towards creating ETANA--DL, a digital library (DL) to help manage these vast quantities of information and to provide various kinds of services. The 5S framework for modeling a DL gives us an edge in understanding this vast and complex information space, as well as in designing and prototyping a DL to satisfy information needs of archaeologists and other user communities.","Title: Combining structural and citation-based evidence for text classification\nYear: 2004\n\nAbstract: This paper discusses how citation-based information and structural content (e.g., title, abstract) can be combined to improve classification of text documents into predefined categories. We evaluate different measures of similarity derived from the citation structure and the structural content of the collection, and determine how they can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our empirical experiments using documents from the ACM Digital Library and the ACM Computing Classification System show that we can discover similarity functions that work better than using evidence in isolation and whose combined performance through a simple majority voting is comparable to that of Support Vector Machine classifiers.","Title: Connecting Topics in Document Collections with Stepping Stones and Pathways\nYear: 2005\n\nAbstract: In this paper, we present Stepping Stones and Pathways (SSP), an alternative model of building and presenting answers for the cases when queries on document collections cannot be answered just by a ranked list. Stepping Stones can handle questions like: \"What is the relation of topics X and Y?\" SSP addresses when the contents of a small set of related documents is needed as an answer rather than a single document, or when \"query splitting\" is required to satisfactorily explore a document space. Query results are networks of document groups representing topics, each group relating to and connecting (by documents) to other groups in the network. Thus, a network answers the user's information need. We devise new and more effective representations and techniques to visualize such answers, and to involve users as part of the answer-finding process. In order to verify the validity of our approach, and since the questions we aim to answer involve multiple topics, we performed a study involving a custom built broad collection of operating systems research papers, and evaluated the results with interested computer science students, using multiple measures.","Title: Advances in Interactive Digital Multimedia Systems\nYear: 1991\n\nAbstract: This paper introduces basic concepts in digital multimedia systems and surveys recent literature. Background is provided regarding developments in interactive videodiscs, which first made images and video accessible through computer systems. Digital storage media, including optical, magnetic, and network options, are addressed. The characteristics of audio and video and their digital representations are discussed. Because these media are so demanding of space and channel bandwidth, compression methods are reviewed. Standards for digital multimedia are considered. Current multimedia systems are described, and future prospects are indicated.","Title: Domain-specific image geocoding: a case study on Virginia tech building photos\nYear: 2013\n\nAbstract: The use of map-based browser services is of great relevance in numerous digital libraries. The implementation of such services, however, demands the use of geocoded data collections. This paper investigates the use of image content local representations in geocoding tasks. Performed experiments demonstrate that some of the evaluated descriptors yield effective results in the task of geocoding VT building photos. This study is the first step to geocode multimedia material related to the VT April 16, 2007 school shooting tragedy.","Title: Curriculum development for digital libraries\nYear: 2006\n\nAbstract: The Virginia Tech Department of Computer Science (VT CS) and the University of North Carolina at Chapel Hill School of Information and Library Science (UNC SILS) have launched a curriculum development project in the area of digital libraries. Educational resources will be developed based on the ACM/IEEE-CS Computing Curriculum 2001. Lesson plans and modules will be developed in a variety of areas (that cover the topics of papers and conference sessions in the field), evaluated by experts in those areas, and then pilot tested in CS and LIS courses. An analysis of papers on digital library-related topics from several corpora was performed, to identify the areas in which more and less work has already been performed on these topics; this analysis will guide the initial stages of this curriculum development.","Title: Ranking Function Discovery by Genetic Programming for Robust Retrieval\nYear: 2003\n\nAbstract: Ranking functions are instrumental for the success of an information retrieval (search engine) system. However nearly all existing ranking functions are manually designed based on experience, observations and probabilistic theories. This paper tested a novel ranking function discovery technique proposed in (Fan 2003a, Fan2003b) - ARRANGER (Automatic geneRation of RANking functions by GEnetic pRogramming), which uses Genetic Programming (GP) to automatically learn the \"best\" ranking function, for the robust retrieval task. Ranking function discovery is essentially an optimization problem. As the search space here is not a coordinate system, most of the traditional optimization algorithms could not work. However, this ranking discovery problem could be easily tackled by ARRANGER. In our evaluations on 150 queries from the ad-hoc track of TREC 6, 7, and 8, the performance of our system (in average precision) was improved by nearly 16%, after replacing Okapi BM25 function with a function automatically discovered by ARRANGER. By applying pseudo-relevance feedback and ranking fusion on newly discovered functions, we improved the retrieval performance by up to 30%. The results of our experiments showed that our ranking function discovery technique - ARRANGER - is very effective in discovering high-performing ranking functions.","Title: AI and Global Science and Technology Assessment\nYear: 2009\n\nAbstract: Strength in science & technology (S&T) is the foundation of a nation's economic power, so an effective, automated means of continually assessing this strength is critical to understanding a country's economic status. Six essays on global S&T assessment present various research frameworks, computational methods, issues, and results relative to knowledge mapping, scientometrics, information visualization, digital libraries, and multilingual knowledge management.","Title: Incremental, semi-automatic, mapping-based integration of heterogeneous collections into archaeological digital libraries: Megiddo case study\nYear: 2005\n\nAbstract: Automation is an important issue when integrating heterogeneous collections into archaeological digital libraries. We propose an incremental approach through intermediary- and mapping-based techniques. A visual schema mapping tool within the 5S [1] framework allows semi-automatic mapping and incremental global schema enrichment. 5S also helped speed up development of a new multi-dimension browsing service. Our approach helps integrate the Megiddo [2] excavation data into a growing union archaeological DL, ETANA-DL [3].","Title: Building a large thesaurus for information retrieval\nYear: 1988\n\nAbstract: Information retrieval systems that support searching of large textual databases are typically accessed by trained search intermediaries who provide assistance to end users in bridging the gap between the languages of authors and inquirers. We are building a thesaurus in the form of a large semantic network to support interactive query expansion and search by end users. Our lexicon is being built by analyzing and merging data from several large English dictionaries; testing of its value for retrieval is with the SMART and CODER systems.","Title: Incremental clustering for very large document databases: initial MARIAN experience\nYear: 1995\n\nAbstract: Clustering of document databases is useful for both browsing and searching purposes; however, this can be a prohibitively expensive computational process for lai ge collections. This problem is compounded when the clustering structure must reflect a constantly changing database. Therefore, efficient algorithms which maintain an existing clustering structure are desirable, This study provides the details of a large-scale implementation of the Cover-Coefficient-based Incremental Clustering Methodology (C(2)ICM). The experiments performed on a sample of the MARIAN database show that its resource requirements are within practical bounds for most platforms. Furthermore, C(2)ICM offers considerable savings over reclustering. The results of this study will lead to an additional type of browsing and/or searching facility on the Virginia Tech-based MARIAN large online public access library catalog (OPAC) project.","Title: Ensemble PDP-8: eight principles for distributed portals\nYear: 2010\n\nAbstract: Ensemble, the National Science Digital Library (NSDL) Pathways project for Computing, builds upon a diverse group of prior NSDL, DL-I, and other projects. Ensemble has shaped its activities according to principles related to design, development, implementation, and operation of distributed portals. Here we articulate 8 key principles for distributed portals (PDPs). While our focus is on education and pedagogy, we expect that our experiences will generalize to other digital library application domains. These principles inform, facilitate, and enhance the Ensemble R&D and production activities. They allow us to provide a broad range of services, from personalization to coordination across communities. The eight PDPs can be briefly summarized as: (1) Articulation across communities using ontologies. (2) Browsing tailored to collections. (3) Integration across interfaces and virtual environments. (4) Metadata interoperability and integration. (5) Social graph construction using logging and metrics. (6) Superimposed information and annotation integrated across distributed systems. (7) Streamlined user access with IDs. (8) Web 2.0 multiple social network system interconnection.","Title: Building interoperable digital library services: MARIAN, open archives, and the NDLTD\nYear: 2001\n\nAbstract: In this demonstration, we present interoperable and personalized search services for the Networked Digital Library of Theses and Dissertations (NDLTD). Using standard protocols and software, including those specified by the Open Archives Initiative (OAI), distributed sites can share metadata easily. On top of these harvesting protocols, we implement a union collection of theses managed by the MARIAN digital library system. Our demonstration covers aspects of NDLTD, OAI, and MARIAN.","Title: SIMPEL: a superimposed multimedia presentation editor and player\nYear: 2006\n\nAbstract: Summary form only given. In a variety of applications such as learning, we need to integrate multimedia information into convenient packages. The challenges involved in this process are: selecting or working with information elements at sub-document level while retaining the original context; describing the integration or packaging of such elements; and making use of minimal storage during this activity. We developed the superimposed multimedia presentation editor and player (SIMPEL), a tool to address these challenges. SIMPEL allows a user to reference information of many types, at varying granularity, without replicating the referenced information. It also allows the user to compose synchronized multimedia presentations. SIMPEL is in a genre of applications called superimposed applications (SAs), which allow users to superimpose new interpretations over existing or base information. SAs employ \"marks\", references to selected regions within base information. SIMPEL uses the superimposed pluggable architecture for contexts and excerpts (SPARCE), middleware that provides mark management and other services for SAs. SIMPEL has been implemented for Windows in Visual Basic.NET and uses XML for storing presentation data","Title: An OAI compliant content-based image search component\nYear: 2004\n\nAbstract: Advances in data storage and image acquisition technologies haveenabled the creation of large image datasets In order to deal withthese data, appropriate information systems (e.g. image digital libraries) have been developed to efficiently manage such collections. One of the most common retrieval approaches is to employ so--called Content--Based Image Retrieval (CBIR) systems. Basically, these systems try to retrieve images similar to auser--defined pattern (e.g. image example). Their goal is to supportimage retrieval based on content properties (e.g. shape, color, or texture), which are often encoded in terms of imagedescriptors This demonstration presents a new CBIR system based on configurable components. The main novelty resides in its Content--Based ImageSearch Component (CBISC) that supports queries on image collections CBISC is based on the OAIprinciples, and thus provides an easy--to--install search engine tosupport querying images by content As with the OAI protocol, queriesare posed via HTTP requests and the responses are encoded in XML CBISC encapsulates multidimensional indexstructures to speed up the searchprocess. Furthermore, it supports the use of different imagedescriptors (metric and non--metric; color, texture, and shapedescriptors; with 1D or 2D feature vectors), which canbe easily combined to yield improved effectiveness. We will show thatthis search component can be tailored for particular image collectionsby a trained designer, who carries out a clearly defined set of pilot experiments to select the appropriate descriptors. Image descriptors are typically domain and usage--dependent Further, agiven image can be associated with very many descriptors However, standard CBIR methods only support a fixed set of descriptors CBISC, instead, allows progressive extension of thedescriptor base Figure 1 presents a screen shotshowing the CBISC Configuration Tool developed to support CBISC designers in the configuration process Basically, this processconcerns the description/definition of both the image descriptors thatwill be used to retrieve images by content, and the image database to which the CBISC is related The XML file generated in thisprocess is used during CBISC execution.","Title: Twitter use during an emergency event: the case of the UT Austin shooting\nYear: 2011\n\nAbstract: This poster presents one of our efforts in the context of the Crisis, Tragedy, and Recovery Network (CTRnet) project. One topic studied in this project is the use of social media by government to respond to emergency events in towns and counties. Monitoring social media information for unusual behavior can help identify these events once we can characterize their patterns. As an example, we analyzed the campus shooting in the University of Texas, Austin, on September 28, 2010. In order to study the pattern of communication and the information communicated using social media on that day, we collected publicly available data from Twitter. Collected tweets were analyzed and visualized using the Natural Language Toolkit, word clouds, and graphs. They showed how news and posts related to this event swamped the discussions of other issues.","Title: Usability study of digital libraries: ACM, IEEE-CS, NCSTRL, NDLTD\nYear: 1999\n\nAbstract: If digital libraries are to be used effectively, their user interfaces should be tested and enhanced. We observed 48 participants as they worked with the following digital libraries: ACM, IEEE-CS, NCSTRL, and NDLTD. We discuss how the features of these digital libraries influence the subjects' efforts to perform search and retrieval tasks. Data analysis indicates that the IEEE-CS digital library was rated the best overall and NDLTD had the best search time. We present user recommendations and propose a taxonomy of features that we believe are essential for the design of future digital libraries. Noteworthy is the observation that users' judgements on the importance of different features varied widely between the beginning and end of their test sessions.","Title: Enhancing digital libraries and portals with canonical structures for complex objects\nYear: 2012\n\nAbstract: Individual digital library resources are of interest in their own right, but, in some domains, resources can be part of (perhaps multiple) complex objects. We focus on domains with complex objects where a digital library user can benefit from seeing and browsing a resource in the context of its structure(s). We introduce canonical structures that can represent local digital library structures; the canonical structures allow us to provide sophisticated browsing/navigation aids in a generic way. We evaluate a means to transfer the structure of our resources to a digital library portal. We implement and evaluate approaches based on OAI-PMH and OAI-ORE using Dublin Core--with and without a custom namespace. We also transfer the canonical structure to a portal where our navigation widget is implemented.","Title: Hard Queries can be Addressed with Query Splitting Plus Stepping Stones and Pathways\nYear: 2005\n\nAbstract: A key finding of the Reliable Information Access Workshop of 2003 was that in collections like those used for TREC 6-8, there are a number of hard queries for which no current search engine can return a high quality set of results. Our Stepping Stones and Pathways (SSP) approach may yield an effective solution to such hard problems, as well as support exploration of collections of content not well known to a person (with broad interest and/or complex information needs). Our initial and promising testing of SSP had users prepare two separate short queries in order to launch processing. However, since beginning with a single information need is a more typical initial situation, we have extended the SSP research by exploring query splitting, especially as might apply to handling hard queries. This paper summarizes our recent results and identifies some of the future work needed.","Title: Web Traffic Latency: Characteristics and Implications\nYear: 1998\n\nAbstract: : It is critical to understand WWW latency in order to designbetter HTTP protocols. In this study we characterize Web response timeand examine the effects of proxy caching, network bandwidth, trafficload, persistent connections for a page, and periodicity. Based on studieswith four workloads, we show that at least a quarter of the total elapsedtime is spent on establishing TCP connections with HTTP/1.0. Thedistributions of connection time and elapsed time can be modeled usingPearson,...","Title: Composite document extended retrieval: an overview\nYear: 1985\n\nAbstract: Experimental information retrieval (IR) systems, some dating back to the sixties, have demonstrated the viability of fully automatic document storage and retrieval methodologies with small to medium size bibliographic collections [72]. Many of these experimental systems utilize the vector space model in which each important term (such as a word stem) identifies a different dimension in a space, so that matrix methods and vector operations can be defined on queries and documents. Statistical techniques have been very effective, and probabilistic enhancements have given additional improvements [84]. However, the basic vector space model is oriented towards recording the essential information in the text of a title/abstract combination rather than describing more complex document structures. It is necessary to extend the model in order to handle composite documents.On the other hand, commonly available retrieval systems that employ Boolean logic queries and utilize inverted file storage schemes can without modification accommodate such documents, albeit with somewhat less effectiveness than is possible with more sophisticated systems. Hence, it is also of interest to consider how Boolean logic systems can be extended to give better performance, especially with composite documents, and to integrate those approaches with vector methods.","Title: CTRnet DL for disaster information services\nYear: 2011\n\nAbstract: We describe our work in collecting, analyzing and visualizing online information (e.g., Web documents, images, tweets), which are to be maintained by the Crisis, Tragedy and Recovery Network (CTRnet) digital library. We have been collecting resources about disaster events, as well as campus and other major shooting events, in collaboration with the Internet Archive (IA). Social media data (e.g., tweets, Facebook data) also have been collected and analyzed. Analyzed results are visualized using graphs and tag clouds. Exploratory content-based image retrieval has been applied in one of our image collections. We explain our CTR ontology development methodology and collaboration with Arlington County, VA and IBM, in a Center for Community Security and Resilience funded project.","Title: Integration of complex archeology digital libraries: An ETANA-DL experience\nYear: 2008\n\nAbstract: In this paper, we formalize the digital library (DL) integration problem and propose an overall approach based on the 5S (streams, structures, spaces, scenarios, and societies) framework. We then apply that framework to integrate domain-specific (archeological) DLs, illustrating our solutions for key problems in DL integration. An integrated Archeological DL, ETANA-DL, is used as a case study to justify and evaluate our DL integration approach. More specifically, we develop a minimal metamodel for archeological DLs within the 5S theory. We implement the 5SSuite tool set to cover the process of union DL generation, including requirements gathering, conceptual modeling, rapid prototyping, and code generation. 5SSuite consists of 5SGraph, 5SGen, and SchemaMapper, each of which plays an important role in DL integration. We also propose an approach to integrated DLs based on the 5S formalism, which provides a systematic method to design and implement DL exploring services.","Title: How educators find educational resources online\nYear: 2011\n\nAbstract: Search engines are mostly targeted toward the generic user but educators have specific information needs with specialized information-seeking behaviors. When designing a course, educators may create a syllabus, lecture slides, and use tools as lecture aides. These resources are scattered across a large number of websites and require time and effort in finding them. To design a useful system for educators we must understand the problems they face when they seek, use, and re-use online resources. With that in mind, the Ensemble team conducted focus groups to identify current practices and problems in locating online resources for educational purposes. The data provides better understanding of the information-seeking process of educators that can lead to better educational resource sites.","Title: CRIM: curricular resources in interactive multimedia\nYear: 1999\n\nAbstract: The CRIM project addresses the need for curricular guidelines and educational resources for the Interactive Multimedia area. A digital library / repository allows educators to submit knowledge modules that will be reviewed and made available for use by teachers or students. Recommendations are given for courses and topics, and a process is outlined to reach consensus and improve education. This efforts is connected with the Computer Science Teaching Center, http://www.cstc.org/.","Title: Envision: a user-centered database of computer science literature\nYear: 1995\n\nAbstract: Project Envision is an early NSF-funded digital library effort to develop a multimedia collection of computer science literature with full-text searching and full-content retrieval capabilities. Envision was launched in 1991 in accordance with the ACM Publications Board's plans for encouraging research studies to develop an electronic archive for computer science.","Title: A faster algorithm for constructing minimal perfect hash functions\nYear: 1992\n\nAbstract: Our previous research on one-probe access to large collections of data indexed by alphanumeric keys has produced the first practical minimal perfect hash functions for this problem. Here, a new algorithm is described for quickly finding minimal perfect hash functions whose specification space is very close to the theoretical lower bound, i.e., around 2 bits per key. The various stages of processing are detailed, along with analytical and empirical results, including timing for a set of over 3.8 million keys that was processed on a NeXTstation in about 6 hours.","Title: A study of user behavior in an immersive virtual environment for digital libraries\nYear: 2000\n\nAbstract: In this paper we present a 2x3 factorial design study evaluating the limits and differences on the behavior of 10 users when searching in a virtual reality representation that mimics the arrangement of a traditional library. The focus of this study was the effect of clustering techniques and query highlighting on search strategy users develop in the virtual environment, and whether position or spatial arrangement influenced user behavior. We found several particularities that can be attributed to the differences in the VR environment.This study's results identify: 1) the need of co-designing both spatial arrangement and interaction method; 2) adifficulty novice users faced when using clusters to identify commontopics; 3) the influence of position and distance on users' selection of collection items to inspect; and 4) that users did not search until found the best match, but only until they found a satisfactory match.","Title: Web Response Time and Proxy Caching\nYear: 1998\n\nAbstract: It is critical to understand WWW latency in order to design better HTTP protocols. In this paper we characterize Web response time and examine effects of proxy caching on response time. We show that at least a quarter of the total elapsed time is spent in setting up TCP connections. We also characterize the effect of a user''s network bandwidth on response time. Average connection time from a client via a 33.6 K modem is two times longer than that from a client via switched Ethernet. Contrary to the typical thought about Web proxy caching, this study finds that a single stand alone proxy cache does not always reduce response time. Implications of these results to the HTTP-NG protocol and Web application design also are discussed in the paper.","Title: Digital library education in computer science programs\nYear: 2007\n\nAbstract: In an effort to identify the \"state of the art\" in digital library education in computer science (CS) programs, we analyzed CS courses on digital libraries and digital library-related topics. Fifteen courses that mention digital libraries in the title or short description were identified; of these, five are concerned with digital libraries as the primary topic of the course. The readings from these five courses were analyzed further, in terms of their authors and the journals in which they were published.","Title: Intelligent GP fusion from multiple sources for text classification\nYear: 2005\n\nAbstract: This paper shows how citation-based information and structural content (e.g., title, abstract) can be combined to improve classification of text documents into predefined categories. We evaluate different measures of similarity -- five derived from the citation information of the collection, and three derived from the structural content -- and determine how they can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our experiments with the ACM Computing Classification Scheme, using documents from the ACM Digital Library, indicate that GP can discover similarity functions superior to those based solely on a single type of evidence. Effectiveness of the similarity functions discovered through simple majority voting is better than that of content-based as well as combination-based Support Vector Machine classifiers. Experiments also were conducted to compare the performance between GP techniques and other fusion techniques such as Genetic Algorithms (GA) and linear fusion. Empirical results show that GP was able to discover better similarity functions than GA or other fusion techniques.","Title: Coefficients of combining concept classes in a collection\nYear: 1988\n\nAbstract: This report considers combining information to improve retrieval. The vector space model has been extended so different classes of data are associated with distinct concept types and their respective subvectors. Two collections with multiple concept types are described, ISI-1460 and CACM-3204. Experiments indicate that regression methods can help predict relevance, given query-document similarity values for each concept type. After sampling and transformation of data, the coefficient of determination for the best model was .48 (.66) for ISI (CACM). Average precision for the two collections was 11% (31%) better for probabilistic feedback with all types versus with terms only. These findings may be of particular interest to designers of document retrieval or hypertext systems since the role of links is shown to be especially beneficial.","Title: Development of the CODER system: a testbed for artificial intelligence methods in information retrieval\nYear: 1987\n\nAbstract: The CODER ( Co mposite D ocument E xpert/Extended/Effective R etrieval) system is a testbed for investigating the application of artificial intelligence methods to increase the effectiveness of information retrieval systems. Particular attention is being given to analysis and representation of heterogeneous documents, such as electronic mail digests or messages, which vary widely in style, length, topic, and structure. Since handling passages of various types in these collections is difficult even for experimental systems like SMART, it is necessary to turn to other techniques being explored by information retrieval and artificial intelligence researchers. The CODER system architecture involves communities of experts around active blackboards, accessing knowledge bases that describe users, documents, and lexical items of various types. The initial lexical knowledge base construction work is now complete, and experts for search and time/date handling can perform a variety of processing tasks. User information and queries are being gathered, and a simple distributed skeletal system is operational. It appears that a number of artificial intelligence techniques are needed to best handle such common but complex document analysis and retrieval tasks.","Title: Multilingual Federated Searching Across Heterogeneous Collections\nYear: 1998\n\nAbstract: This article describes a scalable system for searching heterogeneous multilingual collections on the World Wide Web. It details a markup language for describing the characteristics of a search engine and its interface, and a protocol for requesting word translations between languages.","Title: Deduced social networks for an educational digital library\nYear: 2012\n\nAbstract: By analyzing the behavior of previous users, digital libraries can be made to provide new users with more support to find the best information. The AlgoViz Portal collects metadata on algorithm visualizations and associated research literature. We show how logs can be used to discover latent relationships between users, deducing an implicit social network. By clustering the log data, we find different page-viewing patterns, which provide practical information about the different groups of users.","Title: Prototyping Digital Libraries Handling Heterogeneous Data Sources - The ETANA-DL Case Study.\nYear: 2004\n\nAbstract: Information systems used in archaeology have several needs: interoperability among heterogeneous systems, making information available without significant delay, long-term preservation of data, and providing a suite of services to users. In this paper, we show how digital library techniques can be employed to provide solutions to three of these problems. We show this by describing a prototype for an archaeological Digital Library (ETANA-DL). First, ETANA-DL applies and extends the metadata harvesting approach to address some of the needs-interoperability, rapid access to data, and data preservation. Second, we show that availability of a pool of components that implement common DL services has helped in rapidly creating the prototype, which was subsequently used for requirements elicitation. However, understanding complex archaeological information systems is a difficult task. Third, therefore, we describe our efforts to model these systems using the 5S framework, and show how the partially developed model has been used to implement complex services helping users carry out key tasks with the integrated data.","Title: Development of a modern OPAC: from REVTOLC to MARIAN\nYear: 1993\n\nAbstract: Since 1986 we have investigated the problems and possibilities of applying modern information retrieval methods to large online public access library catalogs (OPACs). In the Retrieval Experiment—Virginia Tech OnLine Catalog (REVTOLC) study we carried out a large pilot test in 1987 and a larger, controlled investigation in 1990, with 216 users and roughly 500,000 MARC records. Results indicated that a forms-based interface coupled with vector and relevance feedback retrieval methods would be well received. Recent efforts developing the Multiple Access and Retrieval of Information with Annotations (MARIAN) system have involved used of a specially developed object-oriented DBMS, construction of a client running under NeXTSTEP, programming of a distributed server with a thread assigned to each user session to increase concurrency on a small network of NeXTs, refinement of algorithms to use objects and stopping rules for greater efficiency, usability testing and iterative interface refinement.","Title: Multiple sources with multiple portals: a demonstration of the ensemble computing portal in second life\nYear: 2010\n\nAbstract: This demonstration is an overview of our Ensemble pathway project with group members on-location at the conference and in the virtual world of Second Life from remote locations providing a live walk-through tour of our project online. This approach allows the demonstration to extend beyond the allocated conference session as a means to attract people to JCDL/ICADL.","Title: Categorization of computing education resources with utilization of crowdsourcing\nYear: 2012\n\nAbstract: The Ensemble Portal harvests resources from multiple heterogeneous federated collections. Managing these dynamically increasing collections requires an automatic mechanism to categorize records in to corresponding topics. We propose an approach to use existing ACM DL metadata to build classifiers for harvested resources in the Ensemble project. We also present our experience with utilizing the Amazon Mechanical Turk platform to build ground truth training data sets from Ensemble collections.","Title: Citiviz: A Visual User Interface to the CITIDEL System.\nYear: 2004\n\nAbstract: The Digital Library (DL) field is one of the most promising areas of application for information visualization technology. In this paper, we propose a visual user interface tool kit for digital libraries, to deliver an overview of document sets, with support for interactive direct manipulation. Our system, Citiviz, employs a dynamic hyperbolic tree to display hierarchical relationships among documents, based on where their topics fit into the ACM classification system. Also, Citiviz provides an interactive, animated 2-dimensional scatter plot. With it, users may gain insight by changing various parameters, or may directly jump to a particular document based on its label or location. According to a preliminary evaluation, our system shows advantages in performance and user preference relative to traditional text based DL web interfaces.","Title: A library of reusable model components for visual simulation of the NCSTRL system\nYear: 1998\n\nAbstract: This paper presents a library of reusable model components for visual simulation of the Networked Computer Science Technical Report Library (NCSTRL) and illustrates how a visual simulation model can be developed for a new NCSTRL configuration by way of component reuse with no programming. Such a repository of reusable model components can be created for visual simulation of any digital library for the purpose of performance evaluation and tuning and conducting what-if analyses for different system design configurations.","Title: Support Vector Machines to Weight Voters in a Voting System of Entity Extractors\nYear: 2006\n\nAbstract: Support vector machines are used to combine the outputs of multiple entity extractors, thus creating a composite entity extraction system. The composite system has a significantly higher f-measure than any of the component systems. Compared to a standard voting technique for combining the results of multiple entity extractors, the SVM approach produces comparable precision and recall statistics but tends to utilize fewer of the component entity extractors, thus providing superior computational efficiency, which is critical in practical applications. In this paper, we present our experimental results of comparing a standard voting technique with SVM that each aggregate four entity extractors. We also describe our future plans of integrating agent-based technology into our experimental testbed where we examine the evolution of composite techniques as part of the analysis stream. Given that much of the improvement comes from tuning the algorithms to the data stream with a human-in-the-loop, we are considering the merits of employing cognitive agents that are strategically embedded in the workflow for processing data. As we tune the algorithms for better performance on the data streams, we envision agents learning the patterns of data streams and apply the appropriate tuning to ensure optimality.","Title: Enhancing the ENVISION interface for digital libraries\nYear: 2002\n\nAbstract: To enhance the ENVISION interface and facilitate user interaction, various techniques were considered for better rendering of search results with improved scalability. In this paper we discuss the challenges we encountered and our solutions to those problems.","Title: Hypermedia support for a digital library in CS\nYear: 1995\n\nAbstract: Since 1991 we have been developing a digital library (DL) in computer science and applying if for CS education. NSF has founded two large projects focusing in this area, as well as several related efforts. \"A User-Centered Database for the Computer Science Literature\" ran from 1991 through early 1995, benefited from strong support from ACM, and led to the Envision system [8, 9, 10]. \"Interactive Learning With a Digital Library in Computer Science\" [6, 7] runs from 1993 through early 1997, is supported by ACM as well as other publishers like IEEE-CS, includes efforts at Norfolk State University (NSU), and benefits from extensive hypermedia system support. By late April 1995, thirteen courses were supported by this El (NSF Education Infrastructure) project and over forty thousand accesses a week were logged by our server.","Title: Specification and generation of digital libraries into DSpace using the 5S framework\nYear: 2007\n\nAbstract: While digital library (DL) systems continue to become more powerful and usable, a certain amount of inherent complexity remains in the installation, configuration, and customization of out-of-the-box solutions like DSpace and Greenstone. In this work, we build upon past work in the 5S Framework for Digital Libraries and 5SL DL specification language to devise an XML-based model for the specification of DLs for DSpace. We pair this way of specifying DLs with a generator tool which takes a DL specification that adheres to the model and generates a working DSpace instance that matches the specification.","Title: Species identification: fish images with CBIR and annotations\nYear: 2009\n\nAbstract: Fish species identification is critical to the study of fish ecology and management of fisheries. However, learning to identify fish is difficult for Ichthyology students. Traditionally, dichotomous keys are used for fish identification. They ask questions about the observed specimen, and then, based on the answer, ask more questions until the specimen is identified. This rigid approach does not accommodate the range of learning styles actually utilized by Ichthyology students. Further, keys often differ from distinguishing characteristics of fishes such as \"spinous dorsal fin\", \"forked tail\", \"large eye\", etc. This leads students to supplement the use of keys with other methods such as making personal notes and drawings, annotating fish images, and more recently, using fish information websites, such as Fishbase. Although these methods provide useful additional content, this content is dispersed across heterogeneous sources and can be tedious to manage and access. From a digital library (DL) perspective, we believe that electronic support for fish species identification can be improved considerably to address some of the aforementioned problems. There are many issues to consider, including better support for: 1) describing and accessing fish images; 2) easily managing and accessing user created content, especially that related to parts of images such as markings on drawings and images and associated notes; 3) easily sharing all of this information with others; and 4) a well-integrated solution, providing all of the above listed capabilities. Digital libraries researchers have been working on providing such integrated support for managing and accessing multimedia along with user created content, including annotating digital objects. We are working toward general solutions for DLs, running on popular platforms including DSpace and Fedora, and allowing those in a wide range of disciplines to \"mark\" important parts of digital objects, connect annotations with them, and manage the annotations inside the DL so that users can browse, search, and have objects rendered in the right environment with appropriate annotations. We developed SuperIDR, a small DL with image description and retrieval, providing such integrated support. SuperIDR. enables a user to add content in the form of image markings and annotations. In addition, it provides improved image searching: 1) through text-based search on species descriptions and annotations, where the query could be terms, phrases, or their boolean combination; or 2) through content-based image search on images and annotated-image-marks, where the query could be a complete image or part of an image. Finally, in SuperIDR, a user can browse through species information either through a taxonomic organization of species based on family and genera, or through an electronic version of the dichotomous key. In order to assess the effectiveness of SuperIDR as an aid to species identification, we conducted an experiment in an undergraduate Ichthyology class, where we compared the use of SuperIDR with traditional methods of species identification (either by using the key, personal notes, markings on images, use of websites, notecards, etc., or a combination of the aforementioned methods). We found that students identified more unknown fish specimens correctly with SuperIDR than with traditional methods. Through statistical analysis of sample data, we were able to conclude that the use of SuperIDR yielded a higher likelihood of success in species identification than does the use of traditional methods. We have made improvements to SuperIDR based on feedback received, and will be making it available to download. A natural extension of this system is to make it web-enabled, thus supporting content-sharing across data and user (social) networks. We used fish species identification as the specific scholarly task to situate our research ideas. However, we believe that our work is applicable to any scholarly task/domain involving images with a significant number of details, such as analyzing paintings in art history, examining a building style in architecture, understanding trees in dendrology, etc.","Title: Tuning before feedback: combining ranking discovery and blind feedback for robust retrieval\nYear: 2004\n\nAbstract: Both ranking functions and user queries are very important factors affecting a search engine's performance. Prior research has looked at how to improve ad-hoc retrieval performance for existing queries while tuning the ranking function, or modify and expand user queries using a fixed ranking scheme using blind feedback. However, almost no research has looked at how to combine ranking function tuning and blind feedback together to improve ad-hoc retrieval performance. In this paper, we look at the performance improvement for ad-hoc retrieval from a more integrated point of view by combining the merits of both techniques. In particular, we argue that the ranking function should be tuned first, using user-provided queries, before applying the blind feedback technique. The intuition is that highly-tuned ranking offers more high quality documents at the top of the hit list, thus offers a stronger baseline for blind feedback. We verify this integrated model in a large scale heterogeneous collection and the experimental results show that combining ranking function tuning and blind feedback can improve search performance by almost 30% over the baseline Okapi system.","Title: A Framework for Building Open Digital Libraries\nYear: 2001\n\nAbstract: Digital Libraries (DLs) have traditionally been positioned at the intersection of library science, computer science, and networked information systems. The different underlying philosophies of these three fields has had an unsettling influence on the development of DLs. While library science is fairly mature, networked information systems are constantly evolving to keep pace with Internet innovation. DLs are thus expected to demonstrate the careful management of libraries while supporting standards that evolve at an astonishing pace. This architectural moving target is a predicament that all DLs face sooner or later in their lifecycle, and one that few manage to deal with effectively. To exacerbate this problem, there has been a general desire for systems to be interoperable at the levels of data exchange and service collaboration. Such interoperability requirements necessitated the development of standards such as the Dublin Core Metadata Element Set and the Open Archives Initiative's Protocol for Metadata Harvesting (OAI-PMH). These standards have achieved a degree of success in the DL community largely because of their generality and simplicity. Informed by those lessons, this project is an attempt to consistently extend known interoperability standards to form the basis of a framework of components for building extensible DLs.","Title: Using digital library components for biodiversity systems\nYear: 2004\n\nAbstract: Biodiversity information systems (BISs) involve all kinds of heterogeneous data, which include ecological and geographical features However, available information systems offer very limited support for managing such data in an integrated fashion, and such integration is often based on geographic coordinates alone. Furthermore, such systems do not fully support image content management (e.g. photos of landscapes or living organisms), a requirement of many BIS end--users. In order to meet their needs, these users -- e.g. biologists, environmental experts -- often have to alternate between distinct biodiversity and image information systems to combine information extracted from them. This cumbersome operational procedure is forced on users by lack of interoperability among these systems. This hampers the addition of new data sources, as well as cooperation among scientists. The approach provided in this project to meet these issues is based on taking advantage of advances in Digital Library (DL) innovations to integrate networked collections of heterogeneous data. It focuses on creating the basis for a biodiversity information system under the digital library perspective, combining new techniques of content--based image retrieval and database query processing mechanisms. This approach solves the problem of system switching, and provides users with a flexible platform from which to tailor a BIS to their needs. The main contributions of this project are the following: (a) a generic architecture for managing heterogeneous collections, based ondigital library components, to access heterogeneous biodiversity data sources (text and images), that allows combining text--based andcontent--based queries in a seamless way; and (b) a new component, for content--based image search, integrated into that architecture. The proposed architecture has been implemented by using DL components which are mostly new or recently developed. Furthemore, its implementation uses the Open Archives Initiative (OAI) protocol as a basis for interoperability. This architecture is easily extensible, and provides users a considerable degree of flexibility in data management. To illustrate our claim that this architecture can be applied to several domains, we are investigating its application in building a biodiversity information system on fish species. This solution solves many current problems in this kind of system, allowing handling of images and textual information in an integrated fashion. A new Content-Based Image Search Component has been developed to support queries on image collections. Since this component is based onthe OAI principles, it provides an easy-to-install search engine toquery images by content. It can be readily tailored for a particular collection by a trained designer, who carries out a clearly definedset of pilot experiments. It supports the use of different image descriptors, which can be chosen from the pilot experiment, and theneasily combined to yield improved effectiveness. In addition, it encapsulates a multidimensional index structure to speed up the search process, that also can be easily configured for different image collections.","Title: A digital library framework for biodiversity information systems\nYear: 2006\n\nAbstract: Biodiversity Information Systems (BISs) involve all kinds of heterogeneous data, which include ecological and geographical features. However, available information systems offer very limited support for managing these kinds of data in an integrated fashion. Furthermore, such systems do not fully support image content (e.g., photos of landscapes or living organisms) management, a requirement of many BIS end-users. In order to meet their needs, these users--e.g., biologists, environmental experts--often have to alternate between separate biodiversity and image information systems to combine information extracted from them. This hampers the addition of new data sources, as well as cooperation among scientists. The approach provided in this paper to meet these issues is based on taking advantage of advances in digital library innovations to integrate networked collections of heterogeneous data. It focuses on creating the basis for a next-generation BIS, combining new techniques of content-based image retrieval and database query processing mechanisms. This paper shows the use of this component-based architecture to support the creation of two tailored BIS systems dealing with fish specimen identification using search techniques. Experimental results suggest that this new approach improves the effectiveness of the fish identification process, when compared to the traditional key-based method.","Title: Designing Protocols in Support of Digital Library Componentization\nYear: 2002\n\nAbstract: Reusability always has been a controversial topic in Digital Library (DL) design. While componentization has gained momentum in software engineering in general, there has not been broad DL standardization in component interfaces. Recently, the Open Archives Initiative (OAI) has begun to address this by creating a standard protocol for accessing metadata archives. We propose that the philosophy and approach adopted by the OAI can be extended easily to support inter-component protocols. In particular, we propose building DLs by connecting small components that communicate through a family of lightweight protocols, using XML as the data interchange mechanism. In order to test the feasibility of this, a set of protocols was designed based on the work of the OAI. Components adhering to these protocols were implemented and integrated into production and research DLs. The performance of these components was analyzed from the perspective of execution speed, network traffic, and data consistency. On the whole, this work has shown promise in the approach of applying the fundamental concepts of the OAI protocol to the task of DL component design and implementation.","Title: Shared User Behavior on the World Wide Web\nYear: 1997\n\nAbstract: Abstract: Studying accesses to Web servers from different user communities,helps identify similarities and differences in user access patterns. In this paper we identify invariants that hold across a collection of ten traces representing traffic seen by proxy servers. The traces were collected from university, high school, governmental, industry, and online service provider environments, with request rates that range from a few accesses to thousands of accesses per hour. In most of the workloads,a small portion of the clients are responsible for most of the accesses. In addition most of the accesses go to a small set of servers. By doing a longitudinal study on the collected data we noticed that the identified invariants do not change over a year period. However, the percentage of script generated documents, is increasing.","Title: Developing a concept extraction technique with ensemble pathway\nYear: 2011\n\nAbstract: In this paper, we describe our Concept Extraction technique for Educational Digital libraries (CEED) which applies Conditional Random Fields (CRFs) to extract concepts from the Ensemble Pathway collection. In addition, we discuss how we implement RESTful APIs for concept extraction.","Title: Report on the workshop on web archiving and digital libraries (WADL 2013)\nYear: 2013\n\nAbstract: This workshop explored the integration of Web archiving and digital libraries, so the complete life cycle involved is covered, from creation/authoring, uploading/publishing in the Web (including Web 2.0), (focused) crawling, curation, indexing, exploration (including searching and browsing), (text) analysis, archiving, and up through long-term preservation. It included particular coverage of current topics of interest: challenges facing archiving initiatives, archiving related to disasters, interaction with and use of archive data, applications on an international scale, working with big data, mobile Web archiving, temporal issues, Memento, and SiteStory.","Title: Building Digital Libraries Made Easy: Toward Open Digital Libraries\nYear: 2002\n\nAbstract: Digital libraries (DLs) promote a sharing culture among those who contribute and those who use resources. This same approach works when building Open Digital Libraries (ODLs). Leveraging the intellectual and practical investment made in the Open Archives Initiative through an eXtended Protocol for Metadata Harvesting (XPMH), one can build lightweight protocols to tie together key components that together make up the core of a DL. DL developers in various settings have learned how to apply this framework in a few hours. The ODL approach has been effective with the Computer Science Teaching Center (www.cstc.org), the Networked Digital Library of Theses and Dissertations (www.ndltd.org), and AmericanSouth.org. Hence, to support our Computing and Information Technology Interactive Digital Educational Library (www.citidel.org) and to provide a generic capability for other parts of the US National Science, technology, engineering, and mathematics education Digital Library (www.nsdl.org), we are developing a \"DL-in-a-box\" toolkit. When lightweight protocols, pools of components, and open standard reference models are combined carefully, as suggested in the OCKHAM discussions, both the DL user and developer communities can benefit from the principle of sharing.","Title: What is a successful digital library?\nYear: 2006\n\nAbstract: We synthesize diverse research in the area of digital library (DL) quality models, information systems (IS) success and adoption models, and information-seeking behavior models, to present a more integrated view of the concept of DL success. Such a multi-theoretical perspective, considering user community participation throughout the DL development cycle, supports understanding of the social aspects of DLs and the changing needs of users interacting with DLs. It also helps in determining when and how quality issues can be measured and how potential problems with quality can be prevented.","Title: The Evolution of Scholarly Digital Library Needs in an International Environment: Social Reference Management Systems and Qatar\nYear: 2013\n\nAbstract: Qatar has become an active research producer of data, publications, and other scholarly works. We studied the evolving scholarly activities and needs of researchers in this relatively new research environment, and compared them with previous findings from a well-established environment in the United States. The initial findings shed some light on the similarities and differences in information seeking behavior and information needs. We also highlighted some requirements and solutions appropriate for future international digital libraries and social reference management systems.","Title: CINET: A cyberinfrastructure for network science\nYear: 2012\n\nAbstract: Networks are an effective abstraction for representing real systems. Consequently, network science is increasingly used in academia and industry to solve problems in many fields. Computations that determine structure properties and dynamical behaviors of networks are useful because they give insights into the characteristics of real systems. We introduce a newly built and deployed cyberinfrastructure for network science (CINET) that performs such computations, with the following features: (i) it offers realistic networks from the literature and various random and deterministic network generators; (ii) it provides many algorithmic modules and measures to study and characterize networks; (iii) it is designed for efficient execution of complex algorithms on distributed high performance computers so that they scale to large networks; and (iv) it is hosted with web interfaces so that those without direct access to high performance computing resources and those who are not computing experts can still reap the system benefits. It is a combination of application design and cyberinfrastructure that makes these features possible. To our knowledge, these capabilities collectively make CINET novel. We describe the system and illustrative use cases, with a focus on the CINET user.","Title: Intelligent fusion of structural and citation-based evidence for text classification\nYear: 2005\n\nAbstract: This paper shows how different measures of similarity derived from the citation information and the structural content (e.g., title, abstract) of the collection can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our experiments with the ACM Computing Classification Scheme, using documents from the ACM Digital Library, indicate that GP can discover similarity functions superior to those based solely on a single type of evidence. Effectiveness of the similarity functions discovered through simple majority voting is better than that of content-based as well as combination-based Support Vector Machine classifiers. Experiments also were conducted to compare the performance between GP techniques and other fusion techniques such as Genetic Algorithms (GA) and linear fusion. Empirical results show that GP was able to discover better similarity functions than other fusion techniques.","Title: A digital library for water main break identification and visualization\nYear: 2012\n\nAbstract: This paper describes a prototype of a digital library for water main break identification and visualization. Many utilities rely on an emergency call to detect water main breaks, because breaks are difficult to predict. Collecting the information by call requires time consuming human efforts. Furthermore, it is not archived and not shared with others. Collecting and archiving the information by tweets, news, and web resources helps users to identify relevant water main breaks efficiently. In developing this prototype, we extracted location information from text instead of using GPS data. We also describe the importance of tweet visualization by location, and how we visualize tweets on a map.","Title: Hybrid Partition Inverted Files: Experimental Validation\nYear: 2002\n\nAbstract: The rapid increase in content available in digital forms gives rise to large digital libraries, targeted to support millions of users and terabytes of data. Efficiently retrieving information then is a challenging task due to the size of the collection and its index. In this paper, our high performance \"hybrid\" partition inverted index is validated through experiments with a 100 Gbyte collection from TREC-9 and -10. The hybrid scheme combines the term and the document approaches to partitioning inverted indices across nodes of a parallel system. Experiments on a parallel system show that this organization outperforms the document and the term partitioning schemes. Our hybrid approach should support highly efficient searching for information in a large-scale digital library, implemented atop a network of computers.","Title: Superimposed image description and retrieval for fish species identification\nYear: 2009\n\nAbstract: Fish species identification is critical to the study of fish ecology and management of fisheries. Traditionally, dichotomous keys are used for fish identification. The keys consist of questions about the observed specimen. Answers to these questions lead to more questions till the reader identifies the specimen. However, such keys are incapable of adapting or changing to meet different fish identification approaches, and often do not focus upon distinguishing characteristics favored by many field ecologists and more user-friendly field guides. This makes learning to identify fish difficult for Ichthyology students. Students usually supplement the use of the key with other methods such as making personal notes, drawings, annotated fish images, and more recently, fish information websites, such as Fishbase. Although these approaches provide useful additional content, it is dispersed across heterogeneous sources and can be tedious to access. Also, most of the existing electronic tools have limited support to manage user created content, especially that related to parts of images such as markings on drawings and images and associated notes. We present SuperIDR, a superimposed image description and retrieval tool, developed to address some of these issues. It allows users to associate parts of images with text annotations. Later, they can retrieve images, parts of images, annotations, and image descriptions through text- and content-based image retrieval. We evaluated SuperIDR in an undergraduate Ichthyology class as an aid to fish species identification and found that the use of SuperIDR yielded a higher likelihood of success in species identification than using traditional methods, including the dichotomous key, fish web sites, notes, etc.","Title: A Connection-Centric Survey of Recommender Systems Research\nYear: 2002\n\nAbstract: Recommender systems attempt to reduce information overload and retain customers by selecting a subset of items from a universal set based on user preferences. While research in recommender systems grew out of information retrieval and filtering, the topic ha s steadily advanced into a legitimate and challenging research area of its own. Recommender systems have traditionally been studied from a content-based filtering vs. collaborative design perspective. Recommendations, however, are not delivered within a vacuum, but rather cast within an informal community of users and social context. Therefore, ultimately all recommender systems make connections among people and thus should be surveyed from such a perspective. This viewpoint is under- emphasized in the recommender systems literature. We therefore take a connection-oriented viewpoint toward recommender systems research. We posit that recommendation has an inherently social element and is ultimately intended to connect people either directly as a result of exp licit user modeling or indirectly through the discovery of relationships implicit in extant data. Thus, recommender systems are characterized by how they model users to bring people together: explicitly or implicitly. Finally, user modeling and the connection-centric viewpoint raise broadening and social issues—such as evaluation, targeting, and privacy and trust—which we also briefly address.","Title: An Asian digital libraries perspective\nYear: 2005\n\nAbstract: This introduces a special issue of IP&M that covers some of the best works from the International Conference on Asian Digital Libraries, 2002. Eight papers, from eight countries, cover a broad range of topics and themes. Many present models, algorithms, systems, and/or experiments. There are approaches based on probability theory, linguistics, user-centered design, and multimedia technologies. It is hoped that readers will apply key results, and participate in future ICADL events.","Title: Use and usability in a digital library search system\nYear: 1999\n\nAbstract: Digital libraries must reach out to users from all walks of life, serving information needs at all levels. To do this, they must attain high standards of usability over an extremely broad audience. This paper details the evolution of one important digital library component as it has grown in functionality and usefulness over several years of use by a live, unrestricted community. Central to its evolution have been user studies, analysis of use patterns, and formative usability evaluation. We extrapolate that all three components are necessary in the production of successful digital library systems.","Title: Report on the NSF major educational funding initiative for a National Science, Technology, Engineering, and Mathematics Education Digital Library (NSDL) with special emphasis on the Computing Education component\nYear: 2003\n\nAbstract: The NSDL consists of collections of materials accessible online, as well as many tools and services intended to enhance learning. Tools and services will support students and as well as faculty. This session will provide a status report on the state of the NSDL, its content, tools, and services. The session includes specific presentations of several services included in the NSDL. Session attendees discuss current and proposed initiatives, and offer suggestions about needs of highest priority.","Title: MARIAN: Flexible Interoperability for Federated Digital Libraries\nYear: 2001\n\nAbstract: Federated digital libraries are composed of distributed, autonomous, and often heterogeneous information services but provide users with a transparent, integrated view of collected information. In this paper we discuss a federated system for the Networked Digital Library of Theses and Dissertations (NDLTD), an international consortium of universities, libraries, and other supporting institutions focused on electronic theses and dissertations (ETDs). Federation requires dealing flexibly with differences among systems, ontologies, and data formats while respecting information sources' autonomy. Our solution involves adapting the object-oriented digital library system MARIAN to serve as mediation middleware for the federated NDLTD collection. Components of the solution include: 1) the use and integration of several harvesting techniques; 2) an architecture based on object-oriented ontologies of search modules and metadata; 3) reconciliation of diversity within the harvested data joined to a single collection view for the user; and 4) an integrated framework for addressing such questions as data quality, flexible and efficient search, and scalability.","Title: Introduction to (teaching/learning about) digital libraries\nYear: 2005\n\nAbstract: This tutorial provides a thorough and deep introduction to the DL field, building upon a firm theoretical foundation (starting with \"5S\": Streams, Structures, Spaces, Scenarios, Societies [1]), giving careful definitions and explanations of all the key parts of a \"minimal digital library\", and expanding from that basis to cover key DL issues, illustrated with a well-chosen set of case studies.","Title: The variety of ways in which instructors implement a modular digital library curriculum\nYear: 2009\n\nAbstract: With support from the National Science Foundation, researchers at Virginia Tech and the University of North Carolina developed a curriculum framework and a number of modules for instruction in the area of digital libraries. In 2008, 15 different modules were field tested by 11 instructors at 10 different institutions. As might be expected, instructors adapted these modules to fit the context of their courses, some of which are described here.","Title: Evaluating digital libraries with 5SQual\nYear: 2007\n\nAbstract: This work describes 5SQual, a quantitative quality assessment tool for digital libraries based on the 5S framework. 5SQual aims to help administrators of digital libraries during the implementation and maintenance phases of a digital library, providing ways to verify the quality of digital objects, metadata and services. The tool has been designed in a flexible way, which allows it to be applied to many systems, as long as the necessary data is available. To facilitate the input of these data, the tool provides a wizard-like interface that guides the user through its configuration process.","Title: SIERRA – a superimposed application for enhanced image description and retrieval\nYear: 2006\n\nAbstract: In this demo proposal, we describe our prototype application, SIERRA, which combines text-based and content-based image retrieval and allows users to link together image content of varying document granularity with related data like annotations. To achieve this, we use the concept of superimposed information (SI), which enables users to (a) deal with information of varying granularity (sub-document to complete document), and (b) select or work with information elements at sub-document level while retaining the original context.","Title: Inferring loss-of-heterozygosity from unpaired tumors using high-density oligonucleotide SNP arrays.\nYear: 2006\n\nAbstract: Loss of heterozygosity (LOH) of chromosomal regions bearing tumor suppressors is a key event in the evolution of epithelial and mesenchymal tumors. Identification of these regions usually relies on genotyping tumor and counterpart normal DNA and noting regions where heterozygous alleles in the normal DNA become homozygous in the tumor. However, paired normal samples for tumors and cell lines are often not available. With the advent of oligonucleotide arrays that simultaneously assay thousands of single-nucleotide polymorphism (SNP) markers, genotyping can now be done at high enough resolution to allow identification of LOH events by the absence of heterozygous loci, without comparison to normal controls. Here we describe a hidden Markov model-based method to identify LOH from unpaired tumor samples, taking into account SNP intermarker distances, SNP-specific heterozygosity rates, and the haplotype structure of the human genome. When we applied the method to data genotyped on 100 K arrays, we correctly identified 99% of SNP markers as either retention or loss. We also correctly identified 81% of the regions of LOH, including 98% of regions greater than 3 megabases. By integrating copy number analysis into the method, we were able to distinguish LOH from allelic imbalance. Application of this method to data from a set of prostate samples without paired normals identified known regions of prevalent LOH. We have developed a method for analyzing high-density oligonucleotide SNP array data to accurately identify of regions of LOH and retention in tumors without the need for paired normal samples.","Title: Caching Proxies: Limitations and Potentials\nYear: 1996\n\nAbstract: As the number of World-Wide Web users grow, so does the number of connections made to servers. This increases both network load and server load. Caching can reduce both loads by migrating copies of server files closer to the clients that use those files. Caching can either be done at a client or in the network (by a proxy server or gateway). We assess the potential of proxy servers to cache documents retrieved with the HTTP protocol. We monitored traffic corresponding to three types of educational workloads over a one semester period, and used this as input to a cache simulation. Our main findings are (1) that with our workloads a proxy has a 30-50% maximum possible hit rate no matter how it is designed; (2) that when the cache is full and a document is replaced, least recently used (LRU) is a poor policy, but simple variations can dramatically improve hit rate and reduce cache size; (3) that a proxy server really functions as a second level cache, and its hit rate may tend to decline with time after initial loading given a more or less constant set of users; and (4) that certain tuning configuration parameters for a cache may have little benefit.","Title: Building digital libraries from simple building blocks\nYear: 2003\n\nAbstract: Metadata harvesting has been established by the Open Archives Initiative as a viable mechanism for connecting a provider of data to a purveyor of services. The Open Digital Library model is an emerging framework which attempts to break up the services into appropriate components based also on the basic philosophy of the OAI model. This framework has been applied to various projects and evaluated for its simplicity, extensibility and reusability to support the hypothesis that digital libraries should be built from simple Web service-like components instead of as monolithic software applications.","Title: Using bilingual ETD collections to mine phrase translations\nYear: 2007\n\nAbstract: Phrase translation lists can enhance cross-language information retrieval. However, finding translations for technical phrases is difficult. Bilingual dictionaries have limited coverage for specialized fields, and even more limited coverage of technical phrases. Since phrases can have very specific meanings in technical fields, this limits the quality of translations produced by generic machine translation systems. We hypothesize that digital libraries of electronic theses and dissertations (ETDs) are a good source of technical phrase translations. We have acquired a collection of 3,086 Spanish ETDs about computer science from Scirus, the Universidad Nacional Autónoma de México (Mexico City), and Universidad de las Américas (Puebla). By using English ETDs from NDLTD, we have a comparable corpus of computing-related documents from which to mine phrase translations. We describe our method and its formative evaluation.","Title: Practical enhanced Boolean retrieval: Experiences with the smart and sire systems\nYear: 1988\n\nAbstract: During the last decade, studies with the SMART and SIRE systems have pioneered new techniques for improving the effectiveness of Boolean retrieval. Extended Boolean logic, automatic Boolean query construction, and Boolean feedback yield significant improvements according to a variety of experiments with SMART. Ranking of the output of Boolean queries has been shown to be of value with SIRE. Recent efforts have aimed at adapting SMART to allow large scale testing of these advanced retrieval methods. SIRE has been enhanced to include the p-norm scheme for extended Boolean query processing. Implementation and performance details about SMART and SIRE illustrate how commercially available retrieval systems can be improved to use the fruits of these research efforts.","Title: A Lightweight Protocol between Digital Libraries and Visualization Systems\nYear: 2002\n\nAbstract: A lightweight protocol, VIDI, is proposed to enhance the interoperability of digital libraries (DLs) and visualization systems (VIS). VIDI is related to the Open Digital Library project, which encourages a component-based approach to the construction of digital libraries, implemented by extending the Open Archives Initiative Protocol for Metadata Harvesting. VIDI adds in the concept of a registry of transformers to convert between common metadata and visualization formats. Design and implementation discussions of VIDI explain its feasibility, flexibility, and generality.","Title: Streams, structures, spaces, scenarios, societies (5s): A formal model for digital libraries\nYear: 2004\n\nAbstract: Digital libraries (DLs) are complex information systems and therefore demand formal foundations lest development efforts diverge and interoperability suffers. In this article, we propose the fundamental abstractions of Streams, Structures, Spaces, Scenarios, and Societies (5S), which allow us to define digital libraries rigorously and usefully. Streams are sequences of arbitrary items used to describe both static and dynamic (e.g., video) content. Structures can be viewed as labeled directed graphs, which impose organization. Spaces are sets with operations on those sets that obey certain constraints. Scenarios consist of sequences of events or actions that modify states of a computation in order to accomplish a functional requirement. Societies are sets of entities and activities and the relationships among them. Together these abstractions provide a formal foundation to define, relate, and unify concepts---among others, of digital objects, metadata, collections, and services---required to formalize and elucidate \"digital libraries\". The applicability, versatility, and unifying power of the 5S model are demonstrated through its use in three distinct applications: building and interpretation of a DL taxonomy, informal and formal analysis of case studies of digital libraries (NDLTD and OAI), and utilization as a formal basis for a DL description language.","Title: Using an education oriented digital library to organize and present classes in computing and information\nYear: 2003\n\nAbstract: This demonstration allows conference attendees to gain experience in using the facilities of the NSF National Science Technology Engineering and Mathematics Education Digital Library (NSDL) to prepare and present College or university level classes.","Title: Towards a digital library theory: a formal digital library ontology\nYear: 2008\n\nAbstract: Digital libraries (DLs) have eluded definitional consensus and lack agreement on common theories and frameworks. This makes comparison of DLs extremely difficult, promotes ad-hoc development, and impedes interoperability. In this paper we propose a formal ontology for DLs that defines the fundamental concepts, relationships, and axiomatic rules that govern the DL domain, therefore providing a frame of reference for the discussion of essential concepts of DL design and construction. The ontology is an axiomatic, formal treatment of DLs, which distinguishes it from other approaches that informally define a number of architectural variants. The process of construction of the ontology was guided by 5S, a formal framework for digital libraries. To test its expressibility we have used the ontology to create a taxonomy of DL services and to reason about issues of reusability, extensibility, and composability. Some practical applications of the ontology are also described including: the definition of a digital library services taxonomy, the proposal of a modeling language for digital libraries, and the specification of quality metrics to evaluate digital libraries. We also demonstrate how to use the ontology to formally describe DL architectures and to prove some properties about them, thus helping to further validate the ontology.","Title: Building quality into a digital library\nYear: 2000\n\nAbstract: The Web Characterization Repository contains a collection of internet log files used by researchers to analyze and improve on the architecture of the Web. This repository improves on prior collections by thoroughly testing the log files for format to assure a degree of data quality. Instituting quality control into the digital library addressed many complex issues including technical support for quality assessment, the definition of a workflow to achieve quality control, the assignment of tasks to different people and the definition and automation of quality assessment for log files. By reaching realistic compromises on these issues it was possible to build quality control as an integral part of the digital library.","Title: Virtual DL poster sessions in second life\nYear: 2009\n\nAbstract: In Second Life (SL), a popular general-purpose 3D virtual world, we are supporting the Digital Library community in a variety of ways, including through virtual poster sessions. This brings together the interests of those involved in JCDL 2009, IEEE-TCDL, and NSF-supported work in SL aimed to assist education, training, and dissemination in the digital preservation area.","Title: A Bayesian approach to fingerprint minutia localization and quality assessment using adaptable templates\nYear: 2011\n\nAbstract: Fingerprints continue to serve as a reliable trait for human identification. Feature-based matching techniques, such as those used by Automated Fingerprint Identification Systems (AFIS), have demonstrated remarkable success in minutiae-based matching from good quality prints with relatively large extent. As the image quality degrades and acquired fingerprint area decreases, however, the number of reliable minutiae that can be automatically detected decreases, causing match performance to suffer. This paper presents a novel approach to improving the precision of features that can be extracted from fingerprint images. This is accomplished through improved minutia localization and quality assessment routines that are inspired in part by human visual perception. Initial results have shown an improvement in minutia accuracy for 88.2% of fingerprint minutia sets after applying the proposed localization method. An increase in average quality of true minutiae was found for 98.6% of the fingerprint images when using the proposed quality assessment. The results were obtained using a database of 516 fingerprints with ground truth minutiae.","Title: Improving simulation management systems through ontology generation and utilization\nYear: 2011\n\nAbstract: Content from simulation systems is useful in defining domain ontologies. We describe a digital library process to generate and leverage domain ontologies to support simulation systems tasks. Workflow ontologies may be used to define compositions of simulation-related services. Simulation model ontologies may be used in customizing collection management systems for tasks such as organization, interface construction, and metadata record generation.","Title: Ranking Function Optimization for Effective Web Search by Genetic Programming: An Empirical Study\nYear: 2004\n\nAbstract: Web search engines have become indispensable in our daily life to help us find the information we need. Although search engines are very fast in search response time, their effectiveness in finding useful and relevant documents at the top of the search hit list needs to be improved. In this paper, we report our experience applying Genetic Programming (GP) to the ranking function discovery problem leveraging the structural information of HTML documents. Our empirical experiments using the web track data from recent TREC conferences show that we can discover better ranking functions than existing well-known ranking strategies from IR, such as Okapi, Pt.df. The performance is even comparable to those obtained by Support Vector Machine.","Title: Using automatic metadata extraction to build a structured syllabus repository\nYear: 2007\n\nAbstract: Syllabi are important documents created by instructors for students. Gathering syllabi that are freely available, and creating useful services on top of the collection, will yield a digital library of value for the educational community. However, gathering and building a repository of syllabi is complicated by the unstructured nature of syllabus representation and the lack of a unified vocabulary for syllabus construction. In this paper, we propose an intelligent approach to automatically annotate freely-available syllabi from the Web to benefit the educational community through supporting services such as semantic search. We discuss our detailed process for converting unstructured syllabi to structured representations through entity recognition, segmentation, and association. Our evaluation results demonstrate the effiectiveness of our extractor and also suggest improvements. We hope our work will benefit not only users of our services but also people who are interested in building other genre-specific repositories.","Title: A content-based image retrieval service for archaeology collections\nYear: 2006\n\nAbstract: Archeological sites have heterogeneous information ranging from different artifacts, image data, geo-spatial information, chronological data, and other relevant metadata. ETANA-DL, an archaeology digital library, provides various services by integrating the heterogeneous data available in different collections. This demonstration presents an initial prototype for searching DL objects based on the image content, using the Content-Based Image Search Component (CBISC) from Virginia Tech/State University of Campinas.","Title: Curricula and resources for courses about multimedia (panel session)\nYear: 2000\n\nAbstract: This panel will discuss a recommendation for curricula guidelines for courses about multimedia. Based on conference input, the guidelines will be modified for review prior to future publication by ACM (with other groups). The recommendation will be one of the main results of a June 2000 Dagstuhl workshop led by 4 of the panelists. Dr. Heller, the 5th panelist, also attended that workshop, and is co-PI with the panel moderator on a directly related NSF project, Curriculum Resources in Interactive Multimedia, CRIM, see http://ei.cs.vt.edu/~crim. Each of the panelists has taught courses about multimedia. Each is interested in developing tools/demonstrations/resources to help in those course. Each has a particular area of interest in the multimedia field. Together they constitute a representative group among those who will contribute to and benefit from curricula resources in multimedia.","Title: Multimedia traffic analysis using CHITRA95\nYear: 1995\n\nAbstract: We describe how to investigate collections of trace data representing network delivery of multimedia information with CHITRA95, a tool that allows a user to visualize, query, statistically analyze and test, transform, and model collections of trace data. CHITRA95 is applied to characterize World Wide Web (WWW) traffic from three workloads: students in a classroom of network-connected workstations, graduate students browsing the Web, undergraduates browsing educational and other materials, as well as traffic on a courseware repository server. We explore the inter-access time of files on a server (i.e., recency), the hit rate from a proxy server cache, and the distributions of file sizes and media types requested. The traffic study also yields statistics on the effectiveness of caching to improve transfer rates. In contrast to past WWW traffic studies, we analyze client as well as server traffic; we compare three workloads rather than drawing conclusions from one workload; and we analyze tcpdump logs to calculate the performance improvement in throughput that an end user sees due to caching.","Title: Architecture of an expert system for composite document analysis, representation, and retrieval\nYear: 1987\n\nAbstract: The CODER (COmposite Document Expert/extended/effective Retrieval) project is a multi-yeare effort to investigate how best to apply artificial intelligence methods to increase the effectiveness of information retrieval systems handling collections of composite documents. To ensure system adaptability and to allow controlled experimentation, CODER has been designed as a distributed expert system. The use of individually tailored specialist experts, coupled with standardized blackboard modules for communication and control and external knowledge bases for maintenance of factual world knowledge, allows for quick prototyping, incremental development, and flexibility under change. The system as a whole is being implemented under UNIX as a set of MU-Prolog and C modules communicating through pipes and TCP/IP sockets.","Title: Formal foundations for systematic digital library generation\nYear: 2013\n\nAbstract: Many digital library design, development, and deployment processes are not based on systematic generation activities. The utilization of generation processes enables the precise definition of digital libraries, identification of existing software components, co-generation of multiple digital libraries, and evaluation of a digital library's coverage and completeness. The foundation of a digital library generation process is in the formal framework in which it is described. Two notable formal frameworks have previously been proposed for describing digital libraries and their content, architecture, functionality, and related societies. These two frameworks are merged in this effort to provide the foundation for a generation framework in support of an emerging class of scientific digital libraries.","Title: ETANA-DL: managing complex information applications -- an archaeology digital library\nYear: 2004\n\nAbstract: Archaeological research results in the generation of large quantities of heterogeneous information managed by different projects using custom information systems. We will demonstrate a prototype Digital Library (DL) for integrating and managing archaeological data and providing services useful to various user communities ETANA--DL is a model--based, componentized, extensible, archaeological DL that manages complex information sources using the client--server paradigm of the Open Archives Initiative Protocol for Metadata Harvesting (OAI--PMH).","Title: Enhancing usability in CITIDEL: multimodal, multilingual, and interactive visualization interfaces\nYear: 2004\n\nAbstract: We describe four usability-enhancing interfaces to CITIDEL aimed at improving the user experience and supporting personalized information access by targeted communities. These comprise: a multimodal interaction facility with capability for out-of-turn input, interactive visualizations for exploratory analysis, a translation center exposing multilingual interfaces, as well as traditional usability enhancements. Pilot studies demonstrate the resulting improvements in quality, as measured across a number of metrics.","Title: The Web-DL environment for building digital libraries from the Web\nYear: 2003\n\nAbstract: The Web contains a huge volume of unstructured data, which is difficult to manage. In digital libraries, on the other hand, information is explicitly organized, described, and managed. Community-oriented services are built to attend specific information needs and tasks. In this paper, we describe an environment, Web-DL, that allows the construction of digital libraries from the Web. The Web-DL environment will allow us to collect data from the Web, standardize it, and publish it through a digital library system. It provides support to services and organizational structure normally available in digital libraries, but benefiting from the breadth of the Web contents. We experimented with applying the Web-DL environment to the Networked Digital Library of Theses and Dissertations (NDLTD), thus demonstrating that the rapid construction of DLs from the Web is possible. Also, Web-DL provides an alternative as a largescale solution for interoperability between independent digital libraries.","Title: Exploring digital libraries: integrating browsing, searching, and visualization\nYear: 2006\n\nAbstract: Exploring services for digital libraries (DLs) include two major paradigms, browsing and searching, as well as other services such as clustering and visualization. In this paper, we formalize and generalize DL exploring services within a DL theory. We develop theorems to indicate that browsing and searching can be converted or mapped to each other under certain conditions. The theorems guide the design and implementation of exploring services for an integrated archaeological DL, ETANA-DL. Its integrated browsing and searching can support users in moving seamlessly between these operations, minimizing context switching, and keeping users focused. It also integrates browsing and searching into a single visual interface for DL exploration. A user study to evaluate ETANA-DL's exploring services helped validate our hypotheses.","Title: World-Wide Web and computer science reports\nYear: 1995\n\nAbstract: With the advent of the World-Wide Web, computing professionals have eagerly pursued the idea of moving from a paper-based technical report service to one that employs networked information systems. Many departments keep some version of their reports on an FTP server to help with this process. To facilitate access to CS reports a number of sites have set up lists of these archives (see sidebar).","Title: An Extensible Digital Library Service to Support Network Science.\nYear: 2013\n\nAbstract: Network science research aims to understand the underlying properties of complex networks. Large-scale modeling and simulation is the core of network science research. Existing systems take a long time to run large network science experiments with high performance computing resources. Scientific data management systems currently lack the performance efficiency needed to support this type of computation and data-intensive research. Memoization provides the ability to index, archive, and reuse frequently requested and expensive to re-compute datasets. In this paper, a domain independent memoization service to increase the computational execution process performance within cyberinfrastructure-based systems is described. The service is formulated as an extensible memoization framework for the computational and simulation network science domains that is built on top of well-defined metadata objects. We present extensible concepts, discuss the proposed algorithm and framework architecture, and examine the flexible nature of the framework. The framework was utilized as a part of the CINET cyberinfrastructure-based digital library (DL). Our experimental results indicate an increase in the efficiency of the system and recommendation of the service's inclusion in scientific DLs.","Title: Visual Semantic Modeling of Digital Libraries.\nYear: 2003\n\nAbstract: The current interest from non-experts who wish to build digital libraries (DLs) is strong worldwide. However, since DLs are complex systems, it usually takes considerable time and effort to create and tailor a DL to satisfy specific needs and requirements of target communities/societies. What is needed is a simplified modeling process and rapid generation of DLs. To enable this, DLs can be modeled with descriptive domain-specific languages. A visual tool would be helpful to non-experts so they may model a DL without knowing the theoretical foundations and the syntactic details of the descriptive language. In this paper, we present a domain-specific visual DL modeling tool, 5SGraph. It employs a metamodel that describes DLs using the 5S theory. The output from 5SGraph is a DL model that is an instance of the metamodel, expressed in the 5S description language. Furthermore, 5SGraph maintains semantic constraints specified by the 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph enables component reuse to reduce the time and effort of designers. 5SGraph also is designed to accommodate and integrate several other complementary tools reflecting the interdisciplinary nature of DLs. Thus, tools based on concept maps to fulfill those roles are introduced. The 5SGraph tool has been tested with real users and several modeling tasks in a usability experiment, and its usefulness and learnability have been demonstrated.","Title: Online evaluation in WWW-based courseware\nYear: 1997\n\nAbstract: The QUIZIT system has been developed to support adaptive as well as standard testing, along with automatic grading and record keeping, using the WWW as a delivery vehicle. In connection with our Interactive Learning with a Digital Library in Computer Science project, we have applied QUIZIT to help with a master's level course as well as a large freshman level service course. Preliminary testing has led to various improvements, and it appears that QUIZIT will be well received by both instructors and students. It should port easily to a variety of environments and so could be widely used at other institutions as well.","Title: A genetic programming framework for content-based image retrieval\nYear: 2009\n\nAbstract: The effectiveness of content-based image retrieval (CBIR) systems can be improved by combining image features or by weighting image similarities, as computed from multiple feature vectors. However, feature combination do not make sense always and the combined similarity function can be more complex than weight-based functions to better satisfy the users' expectations. We address this problem by presenting a Genetic Programming framework to the design of combined similarity functions. Our method allows nonlinear combination of image similarities and is validated through several experiments, where the images are retrieved based on the shape of their objects. Experimental results demonstrate that the GP framework is suitable for the design of effective combinations functions.","Title: An expert system for selecting liquid chromatographic separation methods\nYear: 1987\n\nAbstract: The Expert Separation Program (ESP) is an expert system designed to aid the inexperienced analytical chemist in choosing a separation method for High Performance Liquid Chromatography (HPLC). Properties of compounds—molecular weight, solubility, polarity, ionic nature, acid/base character, pH dependence, presence of isomers, and presence of functional groups—drive reasoning from first principles. Prolog supports a production rule approach to selecting and explaining a separation system characterized by: column, solvent system, buffer and detector.","Title: A study of automation from seed URL generation to focused web archive development: the CTRnet context\nYear: 2012\n\nAbstract: In the event of emergencies and disasters, massive amounts of web resources are generated and shared. Due to the rapidly changing nature of those resources, it is important to start archiving them as soon as a disaster occurs. This led us to develop a prototype system for constructing archives with minimum human intervention using the seed URLs extracted from tweet collections. We present the details of our prototype system. We applied it to five tweet collections that had been developed in advance, for evaluation. We also identify five categories of non- relevant files and conclude with a discussion of findings from the evaluation.","Title: Automatically Generating Interfaces for Personalized Interaction with Digital Libraries\nYear: 2004\n\nAbstract: We present an approach to automatically generate interfaces supporting\npersonalized interaction with digital libraries; these interfaces augment the\nuser-DL dialog by empowering the user to (optionally) supply out-of-turn\ninformation during an interaction, flatten or restructure the dialog, and\nenquire about dialog options. Interfaces generated using this approach for\nCITIDEL are described.","Title: Digital libraries for education: case studies\nYear: 2004\n\nAbstract: Digital libraries may have extraordinary impact on education, especially in Asia where vast communities could benefit from improved teaching and learning. We highlight opportunities and challenges, drawing upon three case studies. Thus, we explore how CITIDEL, a discipline-specific Digital Library for Education (DLE), oriented toward computing, has evolved, and constitutes a part of the US National Science Digital Library (NSDL), which includes over 160 projects. By way of contrast, we describe the grass-roots and low-cost global movement toward electronic theses and dissertations led by NDLTD. Summarizing lessons learned from these case studies, we suggest ways forward so that DLEs in Asia may engage the diverse stakeholders whose serious involvement can ensure sustainable success.","Title: Exploring the computing literature with visualization and stepping stones & pathways\nYear: 2006\n\nAbstract: An alternative interpretation of queries involves splitting a query into parts that cover different but connected aspects of the information needed.","Title: Web-DL: an experience in building digital libraries from the web\nYear: 2002\n\nAbstract: The Web contains a huge volume of information, almost all unstructured and, therefore, difficult to manage. In Digital Libraries, however, information is explicitly organized, described, and managed. In this paper, we propose an architecture that allows the construction of digital libraries from the Web, using standard protocols and archival technologies, and incorporating powerful digital library and data extraction tools, thus benefiting from the breadth of the Web contents, but supporting services and organization available in digital libraries. The proposed architecture was applied to the Networked Digital Library of Theses and Dissertations, providing an important first step toward rapid construction of large DLs from the Web, as well as a large-scale solution for interoperability between independent digital libraries.","Title: The effects of fitness functions on genetic programming-based ranking discovery forWeb search\nYear: 2004\n\nAbstract: Genetic-based evolutionary learning algorithms, such as genetic algorithms (GAs) and genetic programming (GP), have been applied to information retrieval (IR) since the 1980s. Recently, GP has been applied to a new IR task-discovery of ranking functions for Web search-and has achieved very promising results. However, in our prior research, only one fitness function has been used for GP-based learning. It is unclear how other fitness functions may affect ranking function discovery for Web search, especially since it is well known that choosing a proper fitness function is very important for the effectiveness and efficiency of evolutionary algorithms. In this article, we report our experience in contrasting different fitness function designs on GP-based learning using a very large Web corpus. Our results indicate that the design of fitness functions is instrumental in performance improvement. We also give recommendations on the design of fitness functions for genetic-based information retrieval experiments.","Title: Lexical relations: enhancing effectiveness of information retrieval systems\nYear: 1980\n\nAbstract: One of the essential features of the \"Meaning Text\" model (MTM) developed by I. A. Mel'chuk et. al. is the special lexicon or ECD ('explanatory and combinatory' dictionary). This component can be thought of as a collection independent thesaurus, and can be applied to improve the effectiveness of an information retrieval system.After outlining the MTM and related work, this paper briefly describes the SMART type of information retrieval system. Applicability of the above-mentioned lexicon to such a system is discussed. In particular, the list of lexical relations included in the ECD is expanded and organized to be more effective for retrieval, partially along the lines suggested by Evens and Smith.Finally, an experimental analysis of the utility of lexical relations in an information retrieval system is discussed. It is shown that lexical relations generally enhance system performance. When all lexical relations are considered in the comparison, the resulting performance is shown, by statistical methods, to make a significant improvement (up to 16.5% at a single recall level); when all lexical relations except for antonyms are considered, the improvement is even greater (up to 20.2% at a single recall level).","Title: SimFusion: measuring similarity using unified relationship matrix\nYear: 2005\n\nAbstract: In this paper we use a Unified Relationship Matrix (URM) to represent a set of heterogeneous data objects (e.g., web pages, queries) and their interrelationships (e.g., hyperlinks, user click-through sequences). We claim that iterative computations over the URM can help overcome the data sparseness problem and detect latent relationships among heterogeneous data objects, thus, can improve the quality of information applications that require com- bination of information from heterogeneous sources. To support our claim, we present a unified similarity-calculating algorithm, SimFusion. By iteratively computing over the URM, SimFusion can effectively integrate relationships from heterogeneous sources when measuring the similarity of two data objects. Experiments based on a web search engine query log and a web page collection demonstrate that SimFusion can improve similarity measurement of web objects over both traditional content based algorithms and the cutting edge SimRank algorithm.","Title: Digital libraries settling the score: 10 years hence and 10 before\nYear: 2004\n\nAbstract: Six panelists and a moderator leverage knowledge of the first ten years of the digital libraries field, to suggest key future directions.","Title: Experiment and analysis services in a fingerprint digital library for collaborative research\nYear: 2011\n\nAbstract: Fingerprint management systems support millions of images and complicated but imperfect image identification algorithms. The forensic community requires a set of digital library services to support large image collections, execute identification algorithms, and analyze experiments that test identification algorithms in development. We present a model and prototype system capable of testing and analyzing fingerprinting algorithms in terms of identification performance based on matches of a known image to partial images, distortions of the images, and sub-regions of the images. These services are provided based on our framework for composing a set of services and a fingerprint image collection. The prototype will be useful in collaborations connecting several algorithm development efforts, and in composing an experimentation workflow. We also describe extensions of these services into other domains.","Title: A scalable data management tool to support epidemiological modeling of large urban regions\nYear: 2007\n\nAbstract: We describe the design and prototype implementation of a data management tool supporting simulation based models for studying the spread of infectious diseases in large urban regions. The need for such tools arises due to diverse and competing disease models, social networks, and experimental designs that are being investigated. A realistic case study produces large amounts of data. Organizing such datasets is necessary for effectively supporting analysts and policy-makers interested in various cases. We report our ongoing efforts to develop EpiDM--an integrated information management tool for interrelated digital resources, where the central piece is EpiDL(a digital library for efficient access to these datasets). The work is unique in terms of the specific application domain, which we are not aware of any such efforts and tools that can be generalized for simulation-based modeling of other sociotechnical systems. EpiDL follows the 5S framework developed in the DL community.","Title: How to Make Intelligent Digital Libraries\nYear: 1994\n\nAbstract: Building digital libraries is one of the most important Grand Challenge problems faced by information professionals. This paper surveys the relevant literature and includes recommendations for research, based on our experience with a digital library for computer science and its use in improving undergraduate education. Of particular interest is the application of intelligent system methods to help provide an effective solution. Mediators or agents are needed throughout the system. It is also important to improve the interface, help with searching, and in general allow the digital library to carry out many of the functions of an expert human intermediary.","Title: Wide area technical report service—technical reports online\nYear: 1994\n\nAbstract: Wide Area Technical Report Service (WATERS) is a distributed database of computer science technical reports. Contributors are departments of computer science that make their reports, stored locally at their sites, available through World-Wide Web and a WAIS search engine. By using WATERS, anyone with access to the Internet can, using a client such as Mosaic browse, search, obtain abstract and bibliographic information, and retrieve technical reports online. The latter assumes that the user's WWW client is set up to launch viewers such as ghostview for Postscript files, xdvi for dvi files, and xtiff for TIFF page images.","Title: A relevance feedback approach for the author name disambiguation problem\nYear: 2013\n\nAbstract: This paper presents a new name disambiguation method that exploits user feedback on ambiguous references across iterations. An unsupervised step is used to define pure training samples, and a hybrid supervised step is employed to learn a classification model for assigning references to authors. Our classification scheme combines the Optimum-Path Forest (OPF) classifier with complex reference similarity functions generated by a Genetic Programming framework. Experiments demonstrate that the proposed method yields better results than state-of-the-art disambiguation methods on two traditional datasets.","Title: Superimposed Information Architecture for Digital Libraries\nYear: 2008\n\nAbstract: A variety of software tools commonly used in research and industry allow a user to select (usually contiguous) segments of content to be annotated, referenced, or otherwise distinguished from a containing document. However, digital libraries (DLs) often curate only full documents, not these selected sub-documents. Thus, sub-documents in a DL may not have the full complement of metadata, and they may not be visible using DL browse and search facilities. We are interested in explicit representation of sub-documents in a DL environment. In this paper, we show how sub-documents may be represented and curated. We focus on the explicit representation of what we call a mark- an encapsulated address of a sub-document along with associated context. Our contributions are: a software architecture for representing marks as first-class objects together with regular documents in a DL; and an implementation of our architecture using existing software packages with modest enhancements. This approach provides new capabilities for the DL with minimal modification to tools and interfaces familiar to the DL user.","Title: Implementing SMART for minicomputers via relational processing With abstract data types\nYear: 1981\n\nAbstract: Designed during the 1960's as a research tool for the field of information retrieval, the SMART system has been operating on an IBM 370 since 1974. SMART is now being enhanced, redesigned, and programmed under the UNIX operating system [28] on a DEC VAX 11/780. The techniques used should allow real-time operation on smaller minicomputers in the PDP 11 family. The implementation provides for a combination of database and information retrieval operations which make it applicable to office automation, personal information system management, and research studies. The SMART vector space model, which treats information requests and stored information records as vectors in an n-space (of terms), is integrated into the relational database model using the concepts of abstract data types (ADTs). Domains of relations are allowed to be any ADT; an extended relational algebra is described with operators that manipulate many complex data structures. After illustrating the application of these concepts to typical SMART tasks, a prototype implementation is outlined. Also included is a discussion of techniques to be employed in a more efficient version.","Title: A hybrid two-stage approach for discipline-independent canonical representation extraction from references\nYear: 2012\n\nAbstract: In education and research, references play a key role. However, extracting and parsing references are difficult problems. One concern is that there are many styles of references; hence, given a surface form, identifying what style was employed is problematic, especially in heterogeneous collections of theses and dissertations, which cover many fields and disciplines, and where different styles may be used even in the same publication. We address these problems by drawing upon suitable knowledge found in the WWW. In particular, we research a two-stage classifier approach, involving multi-class classification with respect to reference styles, and partially solve the problem of parsing surface representations of references. We describe empirical evidence for the effectiveness of our approach and plans for improvement of our methods.","Title: Personal digital library: pim through a 5s perspective\nYear: 2007\n\nAbstract: Information overload and fragmentation problems result from the huge volume of data available in digital formats. This has led to increasing interest in personal information management research. However, current efforts have not fully clarified the thinking in this area due to the lack of theoretical foundations. In this paper, we present a formal framework for personal information management through a personal digital library perspective based upon the 5S approach. This framework includes a formal definition of the components and functionalities for a minimal personal digital library. We also present the primary testing results of our initial implementation of receptor module and behavioral information relevance. Challenges expected in planned future efforts are discussed too, with suggestions for possible solutions. We believe this is one of the first efforts to provide a theoretical foundation for personal information management. Our results and planned work show promise for further doctoral research.","Title: ETANA-ADD: an interactive tool for integrating archaeological DL collections\nYear: 2006\n\nAbstract: ETANA-DL is an archaeology digital library built based on the principles of Open Digital Libraries. A key challenge addressed in ETANA-DL is integration of new archaeological sites. To enable archaeologists to build OAI data providers for easy integration, we developed an interactive software tool for database-to-XML generation, schema mapping, and global archive generation. This tool greatly enhances our ability to build new Open Archives. We tested the tool with data from the Umm el-Jimal site.","Title: 5SGraph demo: a graphical modeling tool for digital libraries\nYear: 2003\n\nAbstract: The current demand from non-experts who wish to build digital libraries is strong worldwide. However, since DLs are complex systems, it usually takes a huge amount of effort and time to create and tailor a digital library to satisfy specific needs and requirements of target communities/societies. What is desired is a simplified modeling process and rapid generation of digital libraries. To enable this, digital libraries should be modeled with descriptive domain-specific languages [1]. In a domain-specific modeling language, the models are made up of elements representing concepts, rules, and terminology that are part of the domain world, as opposed to the code world or generic modeling languages (e.g., UML [2]). A visual modeling tool would be helpful to non-experts so they may model a digital library without knowing the theoretical foundations and the syntactical details of the descriptive language.In this demonstration, we present a domain-specific visual modeling tool, 5SGraph, aimed at modeling digital libraries. 5SGraph is based on a metamodel that describes DLs using the 5S theory [3]. The output from 5SGraph is a digital library model that is an instance of the metamodel, expressed in the 5S description language (5SL) [4].5SGraph presents the metamodel in a structured toolbox, and provides a top-down visual building environment for designers (see Figure 1). The visual proximity of the metamodel and instance model facilitates requirements gathering and simplifies the modeling process. Furthermore, 5SGraph maintains semantic constraints specified by the 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph enables component reuse to reduce the time and efforts of designers. 5SGraph also is designed to be flexible and extensible, able to accommodate and integrate several other complementary tools (e.g., to model scenarios or complex digital objects), reflecting the interdisciplinary nature of digital libraries. The tool has been tested with real users and several modeling tasks in a usability experiment [5] and its usefulness and learnability have been demonstrated.","Title: The XML log standard for digital libraries: analysis, evolution, and deployment\nYear: 2003\n\nAbstract: We describe current efforts and developments building on our proposal for an XML log standard format for digital library (DL) logging analysis and companion tools. Focus is given to the evolution of formats and tools, based on analysis of deployment in several DL systems and testbeds. Recent development of analysis tools also is discussed.","Title: Using a frame-based language for information retrieval.\nYear: 1989\n\nAbstract: With the advent of the information society, many researchers are turning to artificial intelligence techniques to provide effective retrieval over large bodies of textual information. In the CODER system, the mission of which is to provide an environment for experiments in applying AI to information retrieval, a factual representation language (FRL) serves as a tool for knowledge engineering and experimentation. the FRL is a hybrid AI language supporting strong typing for attribute values, a frame system, and Prolog-like relational structures. Inheritance is enforced throughout, and the semantics of type subsumption and object matching are formally defined. A collection of type and object managers called the knowledge administration complex implements this common language for storing knowledge and communicating it within the system. Storage of large numbers of complete knowledge objects (statements in the language) is supported by a system of external knowledge bases. Of the three types of knowledge structures in the language, the frame facility has proven most useful in the retrieval domain. This article discusses the frame construct itself, the implementation of the relevant portions of the knowledge administration complex and external knowledge bases, and the use of frames in retrieval research. It closes with a discussion of the utility of the FRL. (This material is based in part upon work supported by the National Science Foundation under Grant Nos. IST-8418877 and IRI-8703580; by the Virginia Center for Innovative Technology under Grant No. INF-85-016; and by grants from Nimbus Records and AT&T. A more detailed version of this article is available from the VPI&SU Department of Computer Science as Technical Report TR-88-25. © 1989 Wiley Periodicals, Inc.)","Title: Practical minimal perfect hash functions for large databases\nYear: 1992\n\nAbstract: We describe the first practical algorithms for finding minimal perfect hash functions that have been used to access very large databases (i.e., having over 1 million keys). This method extends earlier work wherein an 0(n-cubed) algorithm was devised, building upon prior work by Sager that described an 0(n-to the fourth) algorithm. Our first linear expected time algorithm makes use of three key insights: applying randomness whereever possible, ordering our search for hash functions based on the degree of the vertices in a graph that represents word dependencies, and viewing hash value assignment in terms of adding circular patterns of related words to a partially filled disk. Our second algorithm builds functions that are slightly more complex, but does not build a word dependency graph and so approaches the theoretical lower bound on function specification size. While ultimately applicable to a wide variety of data and file access needs, these algorithms have already proven useful in aiding our work in improving the performance of CD-ROM systems and our construction of a Large External Network Database (LEND) for semantic networks and hypertext/hypermedia collections. Virginia Disc One includes a demonstration of a minimal perfect hash function running on a PC to access a 130,198 word list on that CD-ROM. Several other microcomputer, minicomputer, and parallel processor versions and applications of our algorithm have also been developed. Tests including those wiht a French word list of 420,878 entries and a library catalog key set with over 3.8 million keys have shown that our methods work with very large databases.","Title: Research and development of information retrieval models and their application\nYear: 1989\n\nAbstract: In recent years there has been a rapid growth in interest about information retrieval as new storage, processing, and communication technologies emerge that will aid individuals to directly search for and utilize helpful data, information, and knowledge. Since conventional retrieval systems have numerous limitations it is important to consider work by leading researchers in developing new models and in extending and applying already proposed experimental models. Much of that work has been first presented at 1 of the 11 conferences sponsored by the Association for Computing Machinery (ACM) Special Interest Group on Information Retrieval (SIGIR). This article summarizes and introduces a series of 11 articles that had their origins in papers presented at the Tenth Annual International ACM SIGIR Conference on Research & Development in Information Retrieval, June 3–5, 1987, New Orleans, Louisiana. Seven of those articles appear in this Special Issue; the remaining four and perhaps others derived from the 1987 conference papers will appear in subsequent issues of this journal. The articles and ideas introduced relate to: modeling data, information, and knowledge; Boolean logic; probability theory; artificial intelligence; organizing and encoding information and data; and characteristics of users of retrieval systems.","Title: Social navigation for educational digital libraries\nYear: 2010\n\nAbstract: An educational digital library may store a wealth of diverse educational resources targeting different audiences from young schoolchildren to graduate students to school and college teachers. With the growth of the volume and the diversity of the library, it becomes increasingly difficult for the users to find resources, which are relevant to their age, educational needs, and personal interests. Social navigation techniques could provide valuable help in this context guiding users to the most useful information. Social navigation works by processing traces of past user behavior and using the assembled “collective wisdom” to guide future users. The paper reports our work on the design of social navigation infrastructure for Ensemble, a major educational digital library. We present the organization of both sides of the social navigation process: how social wisdom is collected and how it can be used to guide portal users to valuable resources. We also report the results of our most recent evaluation of the social navigation infrastructure.","Title: The networked digital library of theses and dissertations: Changes in the university community\nYear: 2002\n\nAbstract: DIGITAL LIBRARIES are one of the most effective vehicles for change in higher education. They facilitate collaboration involving\n universities in an international cooperative venture, unlocking scholarly resources, and carrying out functions previously\n limited to publishers. They allow faculty and students to improve learning by drawing on rapidly growing collections of valuable\n content—heretofore largely hidden behind the doors of the library—that include an increasing proportion of multimedia elements\n or interactive software.\n \n The Networked Digital Library of Theses and Dissertations (NDLTD), launched in 1996 and building upon work started in 1987,\n is a federated effort involving well over 120 universities scattered around the globe. Rapidly growing as a result of local,\n state, regional, national, and international efforts, it aims to enhance the skills of all graduate students preparing theses\n or dissertations, so they are empowered to create an electronic thesis or dissertation (ETD) and to effectively use digital\n libraries. As universities move to require submission of ETDs, they build the local infrastructure to support their own students\n in this regard and to dramatically enhance access to this important genre of scholarly publication. NDLTD supports these changes\n and helps ensure that the move to ETDs remains a sustainable initiative that will continue to enhance university libraries\n and publishing.","Title: Using concept maps in digital libraries as a cross-language resource discovery tool\nYear: 2005\n\nAbstract: The concept map, first suggested by Joseph Novak, has been extensively studied as a way for learners to increase understanding. We are automatically generating and translating concept maps from electronic theses and dissertations, for both English and Spanish, as a DL aid to discovery and summarization.","Title: Automatic evaluation of digital libraries with 5SQual\nYear: 2009\n\nAbstract: Digital libraries (DLs) are complex information systems which can present changes in their structure, content, and services. These complexities and dynamics make system maintenance a non-trivial task, since it requires periodical evaluation of the different DL components. Generally, these evaluations are customized per system and are performed only when problems occur and administrator intervention is required. This work aims to change the situation. We present 5SQual, a tool which provides ways to perform automatic and configurable evaluations of some of the most important DL components, among them, digital objects, metadata, and services. The tool implements diverse numeric indicators that are associated with eight quality dimensions described in the 5S quality model. Its generic architecture was developed to be applicable to various DLs and scenarios. In sum, the main contributions of this work include: (i) the design and implementation of 5SQual, a tool that validates a theoretical DL quality model; (ii) the demonstration of the applicability of the tool in several usage scenarios; and (iii) the evaluation (with usability specialists) of its graphical interface specially designed to guide the configuration of 5SQual evaluations. We also present the results of interviews conducted with administrators of real DLs regarding their expectations and opinions about 5SQual.","Title: The effectiveness of automatically structured queries in digital libraries\nYear: 2004\n\nAbstract: Structured or fielded metadata is the basis for many digital library services, including searching and browsing. Yet, little is known about the impact of using structure on the effectiveness of such services. In this paper, we investigate a key research question: do structured queries improve effectiveness in DL searching? To answer this question, we empirically compared the use of unstructured queries to the use of structured queries. We then tested the capability of a simple Bayesian network system, built on top of a DL retrieval engine, to infer the best structured queries from the keywords entered by the user. Experiments performed with 20 subjects working with a DL containing a large collection of computer science literature clearly indicate that structured queries, either manually constructed or automatically generated, perform better than their unstructured counterparts, in the majority of cases. Also, automatic structuring of queries appears to be an effectiveand viable alternative to manual structuring that may significantly reduce the burden on users.","Title: A new framework to combine descriptors for content-based image retrieval\nYear: 2005\n\nAbstract: In this paper, we propose a novel framework using Genetic Programming to combine image database descriptors for content-based image retrieval (CBIR). Our framework is validated through several experiments involving two image databases and specific domains, where the images are retrieved based on the shape of their objects.","Title: Scenario-Based Generation of Digital Library Services.\nYear: 2003\n\nAbstract: We describe the development, implementation, and deployment of a new generic digital library generator yielding implementations of digital library services from models of DL \"societies\" and \"scenarios\". The distinct aspects of our solution are: 1) approach based on a formal, theoretical framework; 2) use of state-of-the-art database and software engineering techniques such as domain-specific declarative languages, scenario synthesis, componentized and model driven architectures; 3) analysis centered on scenario-based design and DL societal relationships; 4) automatic transformations and mappings from scenarios to workflow designs and from these to Java implementations, 5) special attention paid to issues of simplicity of implementation, modularity, reusability, and extensibility. We demonstrate the feasibility of the approach through a number of examples.","Title: EtanaCMV: a visual browsing interface for ETANA-DL based on coordinated multiple views\nYear: 2006\n\nAbstract: Visual interfaces for digital libraries (DLs) provide support for insightful browsing, presentation of search results in a browsing platform, and analysis of records in the DL. We propose the demonstration of a visual interface to ETANA–DL, a growing union archaeological DL. Our interface EtanaCMV is based on a uniform multiple view design and facilitates browsing of DL records that are multidimensional, hierarchical, and categorical in nature. We use distinct panels to allow flexible browsing across multiple dimensions. Bars in each panel denote the various categories in each dimension. EtanaCMV will give the users a quick overview of the collections in the DL during browsing in addition to showing relationships in the harvested collections. Coordination between multiple views is used to present more insights into the data.","Title: US-Korea Collaboration on Digital Libraries: An Overview and Generalization for Pacific Rim Collaboration\nYear: 2002\n\nAbstract: We report on recommendations to remove barriers to worldwide development of digital libraries, drawing upon an Aug. 2000 workshop involving researchers from the US and Korea who met at the San Diego Supercomputer Center. We developed a summary table identifying application domains (e.g., education), institutions engaged in those applications, example activities, technical challenges, and possible benefits. Since education has high priority in Korea, an important opportunity that should be explored is involvement of Koreans in the initiative led by the US NSF to develop the National STEM (Science, Technology, Engineering, and Mathematics) education Digital Library, NSDL.","Title: Digital library 2.0 for educational resources\nYear: 2011\n\nAbstract: We report on focus group feedback regarding the services provided by existing education-related Digital Libraries (DL). Participants provided insight into how they seek educational resources online, and what they perceive to be the shortcomings of existing educational DLs. Along with useful content, social interactions were viewed as important supplements for educational DLs. Such interactions lead to both an online community and new forms of content such as reviews and ratings. Based on our analysis of the focus group feedback, we propose DL 2.0, the next generation of digital library, which integrates social knowledge with DL content.","Title: Networked Digital Library of Theses and Dissertations: Bridging the Gaps for Global Access - Part 1: Mission and Progress\nYear: 2001\n\nAbstract: The Networked Digital Library of Theses and Dissertations (NDLTD) is a collaborative effort of universities around the world to promote creating, archiving, distributing and accessing Electronic Theses and Dissertations (ETDs). Since its inception in 1996, over a hundred universities have joined the initiative, underscoring the importance institutions place on training their graduates in the emerging forms of digital publishing and information access. The outreach and training mission of NDLTD is an ongoing project so in this article we report on the current status of membership and support activities. Recent research has focused on creating a union database that will provide a means to search and retrieve ETDs from the combined collections of NDLTD member institutions. The Virtua system developed by VTLS will serve as the heart of this union database. In order to bridge the gap between the existing distributed institutional archives and a unified collection of ETDs, we have developed a metadata standard especially suited to ETDs - this is then used by partner sites to export their freely-available metadata using the Metadata Harvesting Protocol of the Open Archives Initiative. We also link name authority information into the metadata records to support unique identification of authors and others associated with the works. Additional research efforts include advanced search mechanisms, semantic interoperability, the design and development of multi- and cross-lingual search systems, and software modules that support the development of higher-level services to aid researchers in seeking relevant ETDs.","Title: Moving digital libraries into the student learning space: The GetSmart experience\nYear: 2006\n\nAbstract: The GetSmart system was built to support theoretically sound learning processes in a digital library environment by integrating course management, digital library, and concept mapping components to support a constructivist, six-step, information search process. In the fall of 2002 more than 100 students created 1400 concept maps as part of selected computing classes offered at the University of Arizona and Virginia Tech. Those students conducted searches, obtained course information, created concept maps, collaborated in acquiring knowledge, and presented their knowledge representations. This article connects the design elements of the GetSmart system to targeted concept-map-based learning processes, describes our system and research testbed, and analyzes our system usage logs. Results suggest that students did in fact use the tools in an integrated fashion, combining knowledge representation and search activities. After concept mapping was included in the curriculum, we observed improvement in students' online quiz scores. Further, we observed that students in groups collaboratively constructed concept maps with multiple group members viewing and updating map details.","Title: From concepts to implementation and visualization: tools from a team-based approach to ir\nYear: 2008\n\nAbstract: Researchers have been studying and developing teaching materials for information retrieval (IR), such as [3]. Toolkits also have been built that provide hands-on experience to students. For example, IR-Toolbox [4] is an effort to close the gap between the students' understanding of IR concepts and real-life indexing and search systems. Such tools might be good for helping students in non-technical areas such as in the Library and Information Science field to develop their conceptual model of search engines. However, they do not cover emerging topics and skills, such as content-based image retrieval (CBIR) and fusion search. Although there is open source software (such as those in http://www.searchtools.com/tools/tools-opensource.html) that can be used to teach basic and advanced IR topics, they require a student to have high-level technical knowledge and to spend a long time to gain a practical understanding of these topics. We present a new and rapid approach to teach basic and advanced IR topics, such as text retrieval, web-based IR, CBIR, and fusion search, to Computer Science (CS) graduate students. We designed projects that would help students grasp the abovementioned IR topics. Students, working in teams, were given a practical application to start with -- the Superimposed Application for Image Description and Retrieval [5]. SAIDR (earlier, SIERRA) allows users to associate parts of images with multimedia information such as text annotations. Also, users may retrieve information in one of two 2 ways: (1) Perform text-based retrieval on annotations; (2) Perform CBIR on images and parts of images that look like a query image (or part of a query image). Each team was asked to build an enhancement for this application, involving text retrieval and/or CBIR, in three weeks time. The sub-projects are described in Table 1. The outcome of this activity was that students learned about IR concepts while being able to relate their applicability to a real world problem (Figure 1). Details of these projects may be found at http://collab.dlib.vt.edu/runwiki/wiki.pl?TabletPcImageRetrievalSuperimposedInformation. We will demonstrate the tools developed along with the IR concepts they illustrate (Table 1). We believe these tools may aid others to learn about basic and advanced topics in IR.","Title: Design And Analysis Of A Set-Top Box For Video Streaming Services\nYear: 2002\n\nAbstract: We. design arid validate methods for implementing a software-based digital set-top box for handling concurrent live video streams. Unlike conventional video servers that, handle only read requests to retrieve prerecorded video titles, a set-top box must handle write requests to store concurrent live video streams for later viewing. Moreover, it must react to user interactive functions such as pausing a live video stream while recording the video stream in the background or switching to another live video stream in real-time. The functional requirements of set-top boxes thus are vastly different from that of conventional video servers. We model and identify minimum resource requirements for the set-top box to function respectably based on our design and analyze design trade-offs for achieving certain performance goals.","Title: Entertainment history museums in virtual worlds: video game and music preservation in second life\nYear: 2010\n\nAbstract: This research explores and demonstrates the use of Second Life (the popular 3D virtual world) for the purpose of digitally preserving various aspects of video game and music history. Physical game interfaces like joysticks, advertisements used for games, and famous game characters and cultural icons over the history are displayed and preserved in multiple video game exhibits for different eras. Selected game characters are digitally recreated in 3D format as Second Life avatar appearances. Historical changes of musical instruments, musicians, and genres are displayed and preserved likewise. Selected musical instruments are digitally recreated as 3D models playing their real sounds. Some of them will be available for the visitors to play in basic ways.","Title: \"What is a good digital library?\" - A quality model for digital libraries\nYear: 2007\n\nAbstract: In this article, we elaborate on the meaning of quality in digital libraries (DLs) by proposing a model that is deeply grounded in a formal framework for digital libraries: 5S (Streams, Structures, Spaces, Scenarios, and Societies). For each major DL concept in the framework we formally define a number of dimensions of quality and propose a set of numerical indicators for those quality dimensions. In particular, we consider key concepts of a minimal DL: catalog, collection, digital object, metadata specification, repository, and services. Regarding quality dimensions, we consider: accessibility, accuracy, completeness, composability, conformance, consistency, effectiveness, efficiency, extensibility, pertinence, preservability, relevance, reliability, reusability, significance, similarity, and timeliness. Regarding measurement, we consider characteristics like: response time (with regard to efficiency), cost of migration (with respect to preservability), and number of service failures (to assess reliability). For some key DL concepts, the (quality dimension, numerical indicator) pairs are illustrated through their application to a number of ''real-world'' digital libraries. We also discuss connections between the proposed dimensions of DL quality and an expanded version of a workshop's consensus view of the life cycle of information in digital libraries. Such connections can be used to determine when and where quality issues can be measured, assessed, and improved - as well as how possible quality problems can be prevented, detected, and eliminated.","Title: VT at TREC-2003: The Web Track Report\nYear: 2003\n\nAbstract: which uses Genetic Programming (GP) to discover the \"optimal\" ranking functions for various information needs. From Web Track 2002, the training, testing and validation data sets are constructed in the same manner as in Robust Track. Our ARRANGER engine works on those data sets and automatically searches for the \"best\" ranking functions. The best runs are selected for submission according to their performance on queries in Web track 2002.Our paper is organized as follows. Section 2 states our research objectives. Section 3 describes basic data processing steps. Section 4 summarizes the GP algorithm used in our system and detailed information about how we use GP to find ranking function. Section 5 shows the official submission results in comparison with the other TREC teams.","Title: Interest-based user grouping model for collaborative filtering in digital libraries\nYear: 2004\n\nAbstract: Research in recommender systems focuses on applications such as in online shopping malls and simple information systems. These systems consider user profile and item information obtained from data explicitly entered by users. – where it is possible to classify items involved and to make recommendations based on a direct mapping from user or user group to item or item group. However, in complex, dynamic, and professional information systems, such as Digital Libraries, additional capabilities are needed for recommender systems to support their distinctive features: large numbers of digital objects, dynamic updates, sparse rating data, biased rating data on specific items, and challenges in getting explicit rating data from users. In this paper, we present an interest-based user grouping model for a collaborative recommender system for Digital Libraries. Also, we present several user interfaces that obtain implicit user rating data. Our model uses a high performance document clustering algorithm, LINGO, to extract document topics and user interests from documents users access in a Digital Library. This model is better suited to Digital Libraries than traditional recommender systems because it focuses more on users than items and because it utilizes implicit rating data.","Title: Interdisciplinary curriculum development for digital library education\nYear: 2006\n\nAbstract: The Virginia Tech (VT) Department of Computer Science (CS) and the University of North Carolina at Chapel Hill (UNC-CH) School of Information and Library Science (LIS) are developing curricular materials for digital library (DL) education, appropriate for the CS and LIS communities. Educational modules will be designed, based on input from the project advisory board, Computing Curriculum 2001, the 5S framework, and workshop discussions. These modules will be evaluated, first through expert inspection and, second, through field testing. We are identifying and refining module definitions and scopes, collecting related resources, developing a module template, and creating example modules. These will be presented at the conference. The developed curriculum should contribute to producing well-balanced digital librarians who will graduate from CS or LIS programs.","Title: Sharing the wealth: publishing electronic resources\nYear: 2004\n\nAbstract: This poster describes the publication of educational resources in ACM's online Journal for Educational Resources in Computing (JERIC) and the US National Science Foundation's National STEM Digital Library (NSDL).","Title: Automatic document metadata extraction using support vector machines\nYear: 2003\n\nAbstract: Automatic metadata generation provides scalability and usability for digital libraries and their collections. Machine learning methods offer robust and adaptable automatic metadata extraction. We describe a support vector machine classification-based method for metadata extraction from header part of research papers and show that it outperforms other machine learning methods on the same task. The method first classifies each line of the header into one or more of 15 classes. An iterative convergence procedure is then used to improve the line classification by using the predicted class labels of its neighbor lines in the previous round. Further metadata extraction is done by seeking the best chunk boundaries of each line. We found that discovery and use of the structural patterns of the data and domain based word clustering can improve the metadata extraction performance. An appropriate feature normalization also greatly improves the classification performance. Our metadata extraction method was originally designed to improve the metadata extraction quality of the digital libraries Citeseer [S. Lawrence et al., (1999)] and EbizSearch [Y. Petinot et al., (2003)]. We believe it can be generalized to other digital libraries.","Title: Demonstrating the use of a SenseCam in two domains\nYear: 2006\n\nAbstract: MyLifeBits is both an application and a framework to manage a personal lifetime of memories. We will demonstrate the use of a small digital library that manages data from two Microsoft SenseCams, used by: 1) students in the Virginia-Maryland Regional College of Veterinary Medicine, and 2) students supported by our Assistive Technologies office.","Title: From the WWW and minimal digital libraries, to powerful digital libraries: why and how\nYear: 2005\n\nAbstract: Digital libraries have emerged since the early 1990s, distinguished in part by their emphasis on useful content, helpful organization, and a range of services that include at least indexing, searching, and browsing. In the 5S (Streams, Structures, Spaces, Scenarios, and Societies) formal model for digital libraries we precisely define key concepts and terms, so the field can move beyond the stage of continually explaining basic ideas and debating definitions. Thus, we define a minimal digital library in terms of clear definitions for repository, metadata catalog, services, and societies, which in turn build upon characterizations of digital object, collection, hypertext, etc.","Title: Building Policy, Building Community: An Example from the US National Science, Technology, Engineering, and Mathematics Education Library (NSDL)\nYear: 2002\n\nAbstract: Developing a major national resource such as the US National Science, Technology, Engineering, and Mathematics education Digital Library (NSDL) requires policy and technical expertise. Policy issues are as much a challenge as infrastructure in the construction of such a major digital library. This paper focuses on the policy making structures that have developed since 2000 when the US National Science Foundation began its funding for NSDL. The authors are the Vice Chair and Chair of the NSDL Policy Committee and report here on issues of voice, authority, and central issues for policy construction as these have emerged in the NSDL context.","Title: Can We Get A Better Retrieval Function From Machine?\nYear: 2004\n\nAbstract: The quality of an information retrieval system heavily depends on its retrieval function, which returns a similarity measurement between the query and each document in the collection. Documents are sorted according to their similarity values with the query and those with high rank are assumed to be relevant. Okapi BM25 and their variations are very popular retrieval functions and they seem to be the default retrieval function for the IR research community; and there are many other widely used and well studied functions, for example, Pivoted TFIDF and INQUERY. Most of these retrieval functions being used today are made based on probabilistic theories and they are adjusted in real world according to different contexts and information needs. In this paper, we propose the idea that a good retrieval function can be discovered by a pure machine learning approach, without using probabilistic theories and knowledge-based techniques. Two machine learning algorithms, Support Vector Machine (SVM) and Genetic Programming (GP) are used for retrieval function discovery, and GP is found to be a more effective approach. The retrieval functions discovered by GP might be hard for human interpretation, but their performance is superior to Okapi BM25, one of the most popular functions. The new retrieval function is combined with query expansion techniques and the retrieval performance is improved significantly. Based on our observations in the empirical study, the GP function is more reliable and effective than Okapi BM25 when query expansion techniques are used.","Title: Users, user interfaces, and objects: Envision, a digital library\nYear: 1993\n\nAbstract: Project Envision aims to build a ''user-centered database from the computer science literature,'' initially using the publications of the Association for Computing Machinery (ACM). Accordingly, we have interviewed potential users, as well as experts in library, information, and computer science-to understand their needs, to become aware of their perception of existing information systems, and to collect their recommendations. Design and formative usability evaluation of our interface have been based on those interviews, leading to innovative query formulation and search results screens that work well according to our usability testing. Our development of the Envision database, system software, and protocol for client-server communication builds upon work to identify and represent ''objects'' that will facilitate reuse and high-level communication of information from author to reader (user). All these efforts are leading not only to a usable prototype digital library but also to a set of nine principles for digital libraries, which we have tried to follow, covering issues of representation, architecture, and interfacing.","Title: Using ACM DL paper metadata as an auxiliary source for building educational collections\nYear: 2014\n\nAbstract: Some digital libraries harvest metadata records from multiple content providers to build their collections. However, the quality and quantity of such metadata records are limited by what is harvested. To ensure collection growth, and to expand the scope beyond just what can be harvested, additional content acquisition methods are needed. Accordingly, we discuss how the Ensemble project (a pathway effort in the NSDL) is broadening its collection with the help of machine learning. Since Ensemble aims to aid computing education, we make use of ACM Digital Library records as a resource to help with transfer learning. We have built classifiers that can identify if a potential additional resource is about computing education. We approached this as a cross-domain text classification problem and developed suitable methods for feature extraction and bootstrapping for classifier training. Our experiments on three datasets of computing education metadata records show our approach can enhance the quality and quantity of records being added to Ensemble.","Title: Data mapping framework in a digital library with computational epidemiology datasets\nYear: 2014\n\nAbstract: Computational epidemiology employs computer models and informatics tools to reason about the spatio-temporal spread of diseases. The diversity of models, data sources, data representations, and modalities that are collected, used, and modified motivate the development of a digital library (DL) framework to support computational epidemiology. The heterogeneous content includes metadata, text, tables, spreadsheets, experimental descriptions, and large result files. There is no accepted framework that allows unified access to such content. We propose a framework for a digital library system tailored to such datasets to support computational network epidemiology.","Title: Intelligent digital libraries and tailored services\nYear: 2014\n\nAbstract: next generation of intelligent information systems will emerge from recent digital library (DL) research. One aspect of this is based on intelligent technologies and applications in the DL area. Another aspect is based on advances in DL theory and related progress toward improved quality and integration. Together, these two aspects facilitate automation and empower users. Recent progress toward these goals, and the rich set of future possibilities in this regard, can be understood most clearly in the eScience context. Scientific research produces large amounts of complex, numeric content. A new class of DLs with supporting services for such content is vital to advancing scientific practice. Intelligent services also are needed to automate scientific workflows. Simulation environments are especially well suited for automation with digital libraries. The SimDL framework generates simulation-supporting DL instances. This framework includes a set of service implementations, a software toolkit, formal definitions of services and content, and processes for producing workflows of services and layers. Integrating such DL instances within a scientific research infrastructure leads to the automation of many routine tasks and to more intelligent services. This gives a glimpse of the future of more intelligent information systems.","Title: Altmetrics for Country-Level Research Assessment.\nYear: 2014\n\nAbstract: Changes are occurring in scholarly communication and the geography of science. Policymakersand research funding agencies are looking for ways to measure the comprehensive impact of research and benefit from the research experiences of other nations. Recently, altmetrics have been used to measure broader impact of research activities. In this paper, we study altmetrics based on the country-levelimpact andfind that altmetrics can support research evaluation for all countries studied. We compare altmetrics with several traditional metrics and findsignificant relationshipsbetween country-level altmetrics and the number of publications, citations, h-index, and gross domestic expenditure on research and development (GERD). We also find a significant yearly increase in the number of articles published between 2010 and 2014 that received altmetrics.","Title: Media use during conflicts: information seeking gratifications & efficacy during 2012 Mexican elections\nYear: 2014\n\nAbstract: Public access to accurate and reliable information is fundamental to democracy and democratic decision-making. In conditions of uncertainty and imperfect information, such as during political crises or controversial elections in emerging democracies, reliable information is often difficult to obtain. We investigated the uses and gratifications obtained from diverse information sources available to citizens during the months leading up to Presidential elections in Mexico in July 2012. Uses and gratifications theory states that information seeking is one of several primary needs or motivations for using different media. Reliability of information sources is key to gratification of this need. We conducted a survey about diverse information sources and their reliability with an opportunity sample of young adults at a public state university in Mexico. Our findings indicate that face-to-face and telephone communication with members of a respondent's social network, as well as social media and online news sites, were the most reliable sources of information about the elections. Television broadcasting, especially from government channels, was the least reliable. These results suggest that in conditions of relative uncertainty and imperfect information, social media and alternative (online) news sources about political events are essential to sustaining an informed public.","Title: Recommendation based on Deduced Social Networks in an educational digital library\nYear: 2014\n\nAbstract: Discovering useful resources can be difficult in digital libraries with large content collections. Many educational digital libraries (edu-DLs) host thousands of resources. One approach to avoiding information overload involves modeling user behavior. But this often depends on user feedback, along with the demographic information found in user account profiles, in order to model and predict user interests. However, edu-DLs often host collections with open public access, allowing users to navigate through the system without needing to provide identification. With few identifiable users, building models linked to user accounts provides insufficient data to recommend useful resources. Analyzing user activity on a per-session basis, to deduce a latent user network, can take place even without user profiles or prior use history. The resulting Deduced Social Network (DSN) can be used to improve DL services. An example of a DSN is a graph whose nodes are sessions and whose edges connect two sessions that view the same resource. In this paper we present a recommendation framework for edu-DLs that depends on deduced connections between users. Results show that a recommendation system built from DSN-dependent parameters can improve performance compared to when only text similarity between resources is used. Our approach can potentially improve recommendation for DL resources when implicit user activities (e.g., view, click, search) are abundant but explicit user activities (e.g., account creation, rating, comment) are unavailable.","Title: The evolving genre of electronic theses and dissertations\nYear: 1999\n\nAbstract: Electronic theses and dissertations (ETDs) are a unique genre that is emerging in part as a result of the work to build the Networked Digital Library of Theses and Dissertations (NDLTD). Virginia Tech began requiring ETDs January 1, 1997 and has since received over 1350. Quality has already improved and what one has learned is more broadly shared now due to the intense interest in ETDs. This is a flexible genre that will enhance digital libraries in part because over half contain color images or other multimedia, including audio, video, or VRML files. Due to free access, many have been downloaded thousands of times. As the NDLTD expands, tens of thousands of these will be created each year all over the globe and in the near future the NDLTD will broadly support multilingual and federated searching. This paper presents findings at Virginia Tech as a case study of shifting book-length works to electronic documents for the global digital library.","Title: Reducing descriptor measurement error through bayesian estimation of fingerprint minutia location and direction\nYear: 2012\n\nAbstract: Fingerprint-based recognition relies on the matching of features derived from the ridges and valleys of the friction ridge surface. When a large quantity of good-quality features are available, identification can be made with a high level of confidence. When portions of the fingerprint image are of lower quality, accuracy will suffer in the feature extraction and subsequent matching steps. This study is concerned with the correction of descriptor errors in minutiae (ridge endings and bifurcations), and with evaluation of the effect of feature accuracy on matching performance. The approach applies Bayesian filtering to refine minutia location and direction descriptors, using Sequential Monte Carlo approximation of a joint probability distribution near each minutia. The distribution approximates the location and orientation of the minutia, given measurements on local greyscale information, from which an expectation can be determined. Experimental results have been presented which demonstrate improvement of localisation accuracy with respect to ground truth data when using a well-known minutia extractor. These results are shown to be statistically significant, and to lead to improved matching performance. In addition, the authors were able to reduce the average minutia position error for a set of reference minutiae by 83% when using the proposed refinement method.","Title: Robust feature extraction in fingerprint images using ridge model tracking\nYear: 2012\n\nAbstract: This paper addresses the problem of feature extraction from low-quality regions in fingerprint images. Features such as minutiae are difficult to detect automatically when high levels of noise are present, as in wet, dry, or latent prints. The approach presented here is a novel application of Bayesian filtering to the problem of ridge tracing. A friction ridge is followed by recursively estimating posterior distributions representing the direction of each new step along the ridge. This approach benefits from previous state information when in an area that exhibits low ridge clarity, causing ridge-flow estimation to be unreliable. The new technique has been tested experimentally using a database of 880 grayscale fingerprint images with varying quality. The ability of the proposed method to detect features more reliably is confirmed by a reduction in Equal Error Rate of 2.1% and 2.5% over two traditional methods. In addition, the False Reject Rate was reduced by 11.1%, at a False Accept Rate of 1%, for a group of low-quality images. These results demonstrate a significant improvement, as compared with previous techniques, in the ability to process low-quality fingerprint images.","Title: Temporal analysis of fingerprint impressions\nYear: 2012\n\nAbstract: Fingerprint analysis has been performed on static images since the establishment of friction-ridge patterns as a reliable human trait for identification. The image of a fingerprint can vary considerably, however, as a result of such factors as skin elasticity and pressure on the imaging surface. With today's live-scan imaging devices, changes in appearance are notable as a finger presses against the scanning during acquisition. During the brief imaging period, fingerprint ridges stretch and compress, while some portions of the fingertip display varying levels of visibility and quality. Imaging systems select a single static image frame, thereby ignoring information that is absent from a particular image but present in others. This paper presents a novel approach that employs temporal analysis to a sequence of images captured during enrollment. Minutiae are extracted and tracked throughout the sequence to build a composite template that contains more genuine minutia than are found from simple static analysis. It was discovered, through temporal analysis, that 18.2% of minutiae changed type throughout a single impression sequence. The proposed method led to an increase in the number of minutiae detected by 25% and an improvement by 9.3% in the rank-1 identification rate of a set of partial prints, when using an imposter database of temporal composite templates over static templates.","Title: Digital library initiative: a project for educators in Qatar\nYear: 2013\n\nAbstract: This article presents the first phase of an exciting initiative in the Arabian Gulf State of Qatar that brings together four academic institutions working to develop a digital library infrastructure of people, services, software, hardware, and content related to Qatar. Building on prior work on curricular resources developed for the digital library field and extending them to support Arabic as well as English instruction, educators, librarians, and IT specialists are working with content experts, stakeholders, students, and researchers to identify and preserve Qatar oriented digital library collections and information systems.","Title: Read between the lines: A Machine Learning Approach for Disambiguating the Geo-location of Tweets\nYear: 2015\n\nAbstract: This paper describes a Machine Learning (ML) approach for extracting named entities and disambiguating the location of tweets based on those named entities and related content. We conducted experiments with tweets (e.g., about potholes), and found significant improvement in disambiguating tweet locations using a ML algorithm along with the Stanford NER. Adding state information predicted by our classifiers increases the possibility to find the state-level geo-location unambiguously by up to 80%.","Title: Using Transactional Web Archives To Handle Server Errors\nYear: 2015\n\nAbstract: We describe a web archiving application that handles server errors using the most recently archived representation of the requested web resource. The application is developed as an Apache module. It leverages the transactional web archiving tool SiteStory, which archives all previously accessed representations of web resources originating from a website. This application helps to improve the website's quality of service by temporarily masking server errors from the end user and gaining precious time for the system administrator to debug and recover from server failures. By providing pertinent support to website operations, we aim to reduce the resistance to transactional web archiving, which in turn may lead to a better coverage of web history.","Title: Web Archiving and Digital Libraries (WADL)\nYear: 2015\n\nAbstract: This workshop will explore integration of Web archiving and digital libraries, so the complete life cycle involved is covered: creation/authoring, uploading/publishing in the Web (2.0), (focused) crawling, indexing, exploration (searching, browsing), archiving (of events), etc. It will include particular coverage of current topics of interest, like: big data, mobile web archiving, and systems (e.g., Memento, SiteStory, Hadoop processing).","Title: Big Data Text Summarization for Events: A Problem Based Learning Course\nYear: 2015\n\nAbstract: Problem/project Based Learning (PBL) is a highly effective student-centered teaching method, where student teams learn by solving problems. This paper describes an instance of PBL applied to digital library education. We show the design, implementation, results, and partial evaluation of a Computational Linguistics course that provides students an opportunity to engage in active learning about adding value to digital libraries with large collections of text, i.e., one aspect of \\\"big data.\\\" Students are engaging in PBL with the semester long challenge of generating good English summaries of an event, given a large collection from our webpage archives. Six teams, each working with a different type of event, and applying three different summarization methods, learned how to generate good summaries; these have fair precision relative to the Wikipedia page that describes their event.","Title: The Use and Impact of Social Media during the 2011 Tunisian Revolution.\nYear: 2016\n\nAbstract: Citizen participation is a key factor in open government and a fundamental form of collective problem solving in democratic societies. Citizens need reliable information to support collective sense making and decision-making. During crises, such as political uprisings, reliable information sources are essential for citizens to stay informed and make sense of rapidly changing developments. In countries that exert control over media, citizens try to access alternative information sources, such as unfiltered Internet and social media. Using two rounds of online surveys with young adults in Tunisia, we examined the use of diverse media during the 2011 revolution. Our survey results show that higher perceptions of information reliability, along with the sharing of online information, lead to greater political information efficacy (PIE). Prior studies show higher PIE associated with greater democratic participation, which bodes well for collaborative decision-making in the nascent democracy in this North African state.","Title: WADL 2016: Third International Workshop on Web Archiving and Digital Libraries.\nYear: 2016\n\nAbstract: This workshop will explore integration of Web archiving and digital libraries, so the complete life cycle involved is covered: creation/authoring, uploading/publishing in the Web (2.0), (focused) crawling, indexing, exploration (searching, browsing), archiving (of events), etc. It will include particular coverage of current topics of interest, like: big data, mobile web archiving, and systems (e.g., Memento, SiteStory, Hadoop processing).","Title: Big Data Processing of School Shooting Archives.\nYear: 2016\n\nAbstract: Web archives about school shootings consist of webpages that may or may not be relevant to the events of interest. There are 3 main goals of this work; first is to clean the webpages, which involves getting rid of the stop words and non-relevant parts of a webpage. The second goal is to select just webpages relevant to the events of interest. The third goal is to upload the cleaned and relevant webpages to Apache Solr so that they are easily accessible. We show the details of all the steps required to achieve these goals. The results show that representative Web archives are noisy, with 2% - 40% relevant content. By cleaning the archives, we aid researchers to focus on relevant content for their analysis.","Title: Automated arabic text classification with P-Stemmer, machine learning, and a tailored news article taxonomy.\nYear: 2016\n\nAbstract: Arabic news articles in electronic collections are difficult to study. Browsing by category is rarely supported. Although helpful machine-learning methods have been applied successfully to similar situations for English news articles, limited research has been completed to yield suitable solutions for Arabic news. In connection with a Qatar National Research Fund QNRF-funded project to build digital library community and infrastructure in Qatar, we developed software for browsing a collection of about 237,000 Arabic news articles, which should be applicable to other Arabic news collections. We designed a simple taxonomy for Arabic news stories that is suitable for the needs of Qatar and other nations, is compatible with the subject codes of the International Press Telecommunications Council, and was enhanced with the aid of a librarian expert as well as five Arabic-speaking volunteers. We developed tailored stemming i.e., a new Arabic light stemmer called P-Stemmer and automatic classification methods the best being binary Support Vector Machines classifiers to work with the taxonomy. Using evaluation techniques commonly used in the information retrieval community, including 10-fold cross-validation and the Wilcoxon signed-rank test, we showed that our approach to stemming and classification is superior to state-of-the-art techniques.","Title: Anatomy of Scholarly Information Behavior Patterns in the Wake of Social Media.\nYear: 2016\n\nAbstract: As more scholarly content is being born digital or digitized, digital libraries are becoming increasingly vital to researchers leveraging scholarly big data for scientific discovery. Given the abundance of scholarly products-especially in environments created by the advent of social networking services-little is known about international scholarly information needs, information-seeking behavior, or information use. This paper aims to address these gaps by conducting an in-depth analysis of researchers in the United States and Qatar; learn about their research attitudes, practices, tactics, strategies, and expectations; and address the obstacles faced during research endeavors. Based on this analysis, the study identifies and describes new behavior patterns on the part of researchers as they engage in the information-seeking process. The analysis reveals that the use of academic social networks has remarkable effects on various scholarly activities. Further, this study identifies differences between students and faculty members in regard to their use of academic social networks, and it identifies differences between researchers according to discipline. The researchers who participated in the present study represent a range of disciplinary and cultural backgrounds. However, the study reports a number of similarities in terms of the researchersu0027 scholarly activities. Finally, the study illuminates some of the implications for the design of research platforms.","Title: Media use during conflicts: Information seeking and political efficacy during the 2012 Mexican elections.\nYear: 2016\n\nAbstract: Public access to accurate and reliable information is fundamental to democracy and democratic decision-making. In emerging democracies, during political crises or controversial elections, reliable information is often difficult to obtain. In authoritarian regimes, citizens' perceptions of information reliability are tightly linked to trust in government, and both are typically low. Open government policies help build trust that is essential during protests or contentious elections. Uses and gratifications (U&G) theory states that people use diverse media to try to satisfy their need for reliable information. Gratifying this need is tied to the larger concept of political information efficacy (PIE), i.e., the belief a person holds about him/herself as being politically informed and competent to participate in political thought and action. We investigated these inter-related concepts by administering a survey to an opportunity sample of young adults at a public state university in Mexico. We find that respondents perceived that information from face-to-face and telephone communication with members of their social network, as well as online sources were the most reliable. Information from offline sources, such as TV and newspapers, especially pro-government sources, were the least reliable. Further, the information factors of availability, reliability, influence and sharing had positive relationships with PIE. These results suggest that in conditions of uncertain political information, social networks and online information sources are essential to political information efficacy and democratic political participation.","Title: Classifying Short Unstructured Data Using the Apache Spark Platform.\nYear: 2017\n\nAbstract: People worldwide use Twitter to post updates about the events that concern them directly or indirectly. Study of these posts can help identify global events and trends of importance. Similarly, E-commerce applications organize their products in a way that can facilitate their management and satisfy the needs and expectations of their customers. However, classifying data such as tweets or product descriptions is still a challenge. These data are described by short texts, containing in their vocabulary abbreviations of sentences, emojis, hashtags, implicit codes, and other non-standard usage of written language. Consequently, traditional text classification techniques are not effective on these data. In this paper, we describe our use of the Spark platform to implement two classification strategies to process large data collections, where each datum is a short textual description. One of our solutions uses an associative classifier, while the other is based on a multiclass Logistic Regression classifier using Word2Vec as a feature selection and transformation technique. Our associative classifier captures the relationships among words that uniquely identify each class, and Word2Vec captures the semantic and syntactic context of the words. In our experimental evaluation, we compared our solutions, as well as Spark MLlib classifiers. We assessed effectiveness, efficiency, and memory requirements. The results indicate that our solutions are able to effectively classify the millions of data instances composed of thousands of distinct features and classes, found in our digital libraries.","Title: Media Use By Young Tunisians During The 2011 Revolution Vs 2014 Elections\nYear: 2017\n\nAbstract: Citizen participation is a key factor in open government and a fundamental form of collective problem solving in democratic societies. Citizens need reliable information to support collective sense making and decision-making. During crises, such as political uprisings and controversial elections, reliable information sources are essential for citizens to stay informed and make sense of rapidly changing developments. In countries that exert control over media, citizens try to access alternative information sources, such as unfiltered Internet and social media. Using two rounds of surveys with young, educated adults in Tunisia, we examined their use of diverse information sources during the 2011 revolution. We update these findings with a third survey round asking similar questions to young, educated Tunisian adults' about their use of diverse information sources during the 2014 presidential and parliamentary elections. Our results show there have been dramatic changes in the use and perceptions of the reliability of broadcast media as Tunisia builds a new government with more open participation and national communication media. The Internet and social media still play an important role in informing the Tunisian public, but new government and private sources are perceived as significantly more reliable than they were under the authoritarian regime overthrown by the 2011 revolution. Our election survey results show that higher perceptions of information reliability, along with the sharing of online information, lead to greater political information efficacy (PIE). Prior studies show higher PIE is associated with greater democratic participation. This finding bodes well for the nascent democracy emerging in this small North African state.","Title: Focused crawler for events.\nYear: 2018\n\nAbstract: There is need for an Integrated Event Focused Crawling system to collect Web data about key events. When a disaster or other significant event occurs, many users try to locate the most up-to-date information about that event. Yet, there is little systematic collecting and archiving anywhere of event information. We propose intelligent event focused crawling for automatic event tracking and archiving, ultimately leading to effective access. We developed an event model that can capture key event information, and incorporated that model into a focused crawling algorithm. For the focused crawler to leverage the event model in predicting webpage relevance, we developed a function that measures the similarity between two event representations. We then conducted two series of experiments to evaluate our system about two recent events: California shooting and Brussels attack. The first experiment series evaluated the effectiveness of our proposed event model representation when assessing the relevance of webpages. Our event model-based representation outperformed the baseline method (topic-only); it showed better results in precision, recall, and F1-score with an improvement of 20% in F1-score. The second experiment series evaluated the effectiveness of the event model-based focused crawler for collecting relevant webpages from the WWW. Our event model-based focused crawler outperformed the state-of-the-art baseline focused crawler (best-first); it showed better results in harvest ratio with an average improvement of 40%.","Title: Web Archiving and Digital Libraries (WADL).\nYear: 2018\n\nAbstract: The 2018 edition of the Workshop on Web Archiving and Digital Libraries (WADL) will explore the integration of Web archiving and digital libraries. The workshop aims at addressing aspects covering the entire life cycle of digital resources and will also explore areas such as community building and ethical questions around web archiving.","Title: A Hybrid Model for Role-related User Classification on Twitter.\nYear: 2018\n\nAbstract: To aid a variety of research studies, we propose TWIROLE, a hybrid model for role-related user classification on Twitter, which detects male-related, female-related, and brand-related (i.e., organization or institution) users. TWIROLE leverages features from tweet contents, user profiles, and profile images, and then applies our hybrid model to identify a useru0027s role. To evaluate it, we used two existing large datasets about Twitter users, and conducted both intra- and inter-comparison experiments. TWIROLE outperforms existing methods and obtains more balanced results over the several roles. We also confirm that user names and profile images are good indicators for this task. Our research extends prior work that does not consider brand-related users, and is an aid to future evaluation efforts relative to investigations that rely upon self-labeled datasets.","Title: EpiK: A Knowledge Base for Epidemiological Modeling and Analytics of Infectious Diseases\nYear: 2017\n\nAbstract: Computational epidemiology seeks to develop computational methods to study the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems. Recent advances in computing and data sciences have led to the development of innovative modeling environments to support this important goal. The datasets used to drive the dynamic models as well as the data produced by these models presents unique challenges owing to their size, heterogeneity and diversity. These datasets form the basis of effective and easy to use decision support and analytical environments. As a result, it is important to develop scalable data management systems to store, manage and integrate these datasets. In this paper, we develop EpiK—a knowledge base that facilitates the development of decision support and analytical environments to support epidemic science. An important goal is to develop a framework that links the input as well as output datasets to facilitate effective spatio-temporal and social reasoning that is critical in planning and intervention analysis before and during an epidemic. The data management framework links modeling workflow data and its metadata using a controlled vocabulary. The metadata captures information about storage, the mapping between the linked model and the physical layout, and relationships to support services. EpiK is designed to support agent-based modeling and analytics frameworks—aggregate models can be seen as special cases and are thus supported. We use semantic web technologies to create a representation of the datasets that encapsulates both the location and the schema heterogeneity. The choice of RDF as a representation language is motivated by the diversity and growth of the datasets that need to be integrated. A query bank is developed—the queries capture a broad range of questions that can be posed and answered during a typical case study pertaining to disease outbreaks. The queries are constructed using SPARQL Protocol and RDF Query Language (SPARQL) over the EpiK. EpiK can hide schema and location heterogeneity while efficiently supporting queries that span the computational epidemiology modeling pipeline: from model construction to simulation output. We show that the performance of benchmark queries varies significantly with respect to the choice of hardware underlying the database and resource description framework (RDF) engine.","Title: Visualizing user communities and usage trends of digital libraries based on user tracking information\nYear: 2006\n\nAbstract: We describe VUDM, our Visual User-model Data Mining tool, and its application to data logged regarding interactions of 1,200 users of the Networked Digital Library of Theses and Dissertations (NDLTD). The goals of VUDM are to visualize social networks, patrons' distributions, and usage trends of NDLTD. The distinctive approach of this research is that we focus on analysis and visualization of users' implicit rating data, which was generated based on user tracking information, such as sending queries and browsing result sets – rather than focusing on explicit data obtained from a user survey, such as major, specialties, years of experience, and demographics. The VUDM interface uses spirals to portray virtual interest groups, positioned based on inter-group relationships. VUDM facilitates identifying trends related to changes in interest, as well as concept drift. A formative evaluation found that VUDM is perceived to be effective for five types of tasks. Future work will aim to improve the understandability and utility of VUDM.","Title: Machine Learning Approach for Homepage Finding Task\nYear: 2002\n\nAbstract: This paper describes new machine learning approaches to predict the correct homepage in response to a user's homepage finding query. This involves two phases. In the first phase, a decision tree is generated to predict whether a URL is a homepage URL or not. The decision tree then is used to filter out non-homepages from the web pages returned by a standard vector space information retrieval system. In the second phase, a logistic regression analysis is used to combine multiple sources of evidence based on the homepages remaining from the first step to predict which homepage is most relevant to a user's query. 100 queries are used to train the logistic regression model and another 145 testing queries are used to evaluate the model derived. Our results show that about 84% of the testing queries had the correct homepage returned within the top 10 pages. This shows that our machine learning approaches are effective since without any machine learning approaches, only 59% of the testing queries had their correct answers returned within the top 10 hits.","Title: Anatomy of Scholarly Information Behavior Patterns in the Wake of Academic Social Media Platforms.\nYear: 2019\n\nAbstract: As more scholarly content is born digital or converted to a digital format, digital libraries are becoming increasingly vital to researchers seeking to leverage scholarly big data for scientific discovery. Although scholarly products are available in abundance—especially in environments created by the advent of social networking services—little is known about international scholarly information needs, information-seeking behavior, or information use. The purpose of this paper is to address these gaps via an in-depth analysis of the information needs and information-seeking behavior of researchers, both students and faculty, at two universities, one in the USA and the other in Qatar. Based on this analysis, the study identifies and describes new behavior patterns on the part of researchers as they engage in the information-seeking process. The analysis reveals that the use of academic social networks has notable effects on various scholarly activities. Further, this study identifies differences between students and faculty members in regard to their use of academic social networks, and it identifies differences between researchers according to discipline. Although the researchers who participated in the present study represent a range of disciplinary and cultural backgrounds, the study reports a number of similarities in terms of the researchers’ scholarly activities.","Title: ScanBank: A Benchmark Dataset for Figure Extraction from Scanned Electronic Theses and Dissertations\nYear: 2021\n\nAbstract: We focus on electronic theses and dissertations (ETDs), aiming to improve access and expand their utility, since more than 6 million are publicly available, and they constitute an important corpus to aid research and education across disciplines. The corpus is growing as new born-digital documents are included, and since millions of older theses and dissertations have been converted to digital for...","Title: Automatic Metadata Extraction Incorporating Visual Features from Scanned Electronic Theses and Dissertations\nYear: 2021\n\nAbstract: Electronic Theses and Dissertations (ETDs) contain domain knowledge that can be used for many digital library tasks, such as analyzing citation networks and predicting research trends. Automatic metadata extraction is important to build scalable digital library search engines. Most existing methods are designed for born-digital documents such as GROBID, CERMINE, and ParsCit, so they often fail to ...","Title: Teaching Natural Language Processing through Big Data Text Summarization with Problem-Based Learning\nYear: 2020\n\nAbstract: Natural language processing (NLP) covers a large number of topics and tasks related to data and information management, leading to a complex and challenging teaching process. Meanwhile, problem-based learning is a teaching technique specifically designed to motivate students to learn efficiently, work collaboratively, and communicate effectively. With this aim, we developed a problem-based learning course for both undergraduate and graduate students to teach NLP. We provided student teams with big data sets, basic guidelines, cloud computing resources, and other aids to help different teams in summarizing two types of big collections: Web pages related to events, and electronic theses and dissertations (ETDs). Student teams then deployed different libraries, tools, methods, and algorithms to solve the task of big data text summarization. Summarization is an ideal problem to address learning NLP since it involves all levels of linguistics, as well as many of the tools and techniques used by NLP practitioners. The evaluation results showed that all teams generated coherent and readable summaries. Many summaries were of high quality and accurately described their corresponding events or ETD chapters, and the teams produced them along with NLP pipelines in a single semester. Further, both undergraduate and graduate students gave statistically significant positive feedback, relative to other courses in the Department of Computer Science. Accordingly, we encourage educators in the data and information management field to use our approach or similar methods in their teaching and hope that other researchers will also use our data sets and synergistic solutions to approach the new and challenging tasks we addressed.","Title: Introduction to Digital Libraries\nYear: 2021\n\nAbstract: This tutorial is a thorough and deep introduction to the Digital Libraries (DL) field, providing a firm foundation: covering key concepts and terminology, as well as services, systems, technologies, methods, standards, projects, issues, and practices. It introduces and builds upon a firm theoretical foundation (starting with the ‘5S’ set of intuitive aspects: Streams, Structures, Spaces, Scenarios...","Title: Numerically Trained Ultrasound AI for Monitoring Tool Degradation\nYear: 2022\n\nAbstract: Monitoring tool degradation during manufacturing can ensure product accuracy and reliability. However, due to variations in degradation conditions and complexity in signal analysis, effective and broadly applicable monitoring is still challenging to achieve. Herein, a novel monitoring method using ultrasound signals augmented with a numerically trained machine learning technique is reported to monitor the wear condition of friction stir welding and processing tools. Ultrasonic signals travel axially inside the tools, and even minor tool wear will change the time and amplitude of the reflected signal. An artificial intelligence (AI) algorithm is selected as a suitable referee to identify the small variations in the tool conditions based on the reflected ultrasound signals. To properly train the AI referee, a human-error-free data bank using numerical simulation is generated. The simulation models the experimental conditions with high fidelity and can provide comparable ultrasound signals. As a result, the trained AI model can recognize the tool wear from real experiments with subwavelength accuracy prediction of the worn amount on the tool pins.","Title: How Should One Explore the Digital Library of the Future?\nYear: 2021\n\nAbstract: This article partially addresses a challenge from Licklider in his 1965 book on “Libraries of the Future,” focusing on how to build extensible digital libraries that can dramatically expand the support of exploration. A new methodology connects the efforts of User eXperience researchers with those of subject matter experts (domain scientists, curators, researchers, and so on) and developers. This allows constructing a knowledge graph representing the relationships among goals, tasks, workflows, and services. A reasoner empowers authorized users to have their goals met with suitable workflows that are dynamically generated and executed. Student teams have applied the new methodology to support users interested in tweets, web pages, or electronic theses and dissertations, as well as those curating and experimenting with those collections. Exploration is thus broadened across content types and their elements, with an extensible set of services, to address an arbitrary set of stakeholder goals.","Title: Web Archiving and Digital Libraries (WADL) 2022\nYear: 2022\n\nAbstract: The 2022 edition of the Workshop on Web Archiving and Digital Libraries (WADL) will explore the integration of web archiving and digital libraries. The workshop aims at addressing aspects covering the entire life cycle of digital resources, including creation/authoring, uploading/publishing, crawling, indexing, exploration, and archiving. It will also explore areas such as archiving processes and tools for “non-traditional” resources such as social media, scholarly and government datasets, 3D objects, and digital online art. CCS CONCEPTS • Information systems $\\rightarrow$ Digital libraries and archives;"],"string":"[\n \"Title: Introduction to digital libraries\\nYear: 2016\\n\\nAbstract: This tutorial is a thorough and deep introduction to the DL field, providing a firm foundation: covering key concepts and terminology, as well as services, systems, technologies, methods, standards, projects, issues, and practices. It introduces and builds upon a firm theoretical foundation (starting with the '5S' set of intuitive aspects: Streams, Structures, Spaces, Scenarios, Societies), giving careful definitions and explanations of all the key parts of a 'minimal digital library', and expanding from that basis to cover key DL issues. Illustrations come from a set of case studies. Attendees will be exposed to four Morgan & Claypool books that elaborate on 5S, 2012-2014. Complementing the coverage of '5S' will be an overview of key aspects of the DELOS Reference Model and DL.org activities. Further, use of a Hadoop cluster supporting DLs will be described.\",\n \"Title: What if there were desktop access to the computer science literature?\\nYear: 1993\\n\\nAbstract: What if there were an electronic computer science library? Consider the possibilities of having your favorite publications available within finger's reach. Consider Project Envision, an ongoing effort to build a user-centered database from the computer science literature. This paper describes the project's first year progress, stressing the underlying motivation, user-centered development, and the overall design.\",\n \"Title: Overview of digital libraries\\nYear: 2002\\n\\nAbstract: This tutorial will start with an overview of definitions, foundations, scenarios, and perspectives. It will cover a variety of issues, including search, retrieval, and resource discovery; multimedia/hypermedia; metadata (e.g., Dublin Core); electronic publishing; document models and representations; SGML and XML; database approaches; agents and distributed processing; 2D and 3D interfaces and visualizations; metrics; architectures and interoperability; educational and social concerns; commerce and intellectual property rights, among others.\",\n \"Title: Using CITIDEL to develop and share class plans\\nYear: 2004\\n\\nAbstract: This demonstration will illustrate the use of existing and proposed tools in CITIDEL for finding existing resources to integrate into a course and for developing well structured descriptions of class and laboratory activities for sharing with the computing community.\",\n \"Title: Removal policies in network caches for World-Wide Web documents\\nYear: 1996\\n\\nAbstract: World-Wide Web proxy servers that cache documents can potentially reduce three quantities: the number of requests that reach popular servers, the volume of network traffic resulting from document requests, and the latency that an end-user experiences in retrieving a document. This paper examines the first two using the measures of cache hit rate and weighted hit rate (or fraction of client-requested bytes returned by the proxy). A client request for an uncached document may cause the removal of one or more cached documents. Variable document sizes and types allow a rich variety of policies to select a document for removal, in contrast to policies for CPU caches or demand paging, that manage homogeneous objects. We present a taxonomy of removal policies. Through trace-driven simulation, we determine the maximum possible hit rate and weighted hit rate that a cache could ever achieve, and the removal policy that maximizes hit rate and weighted hit rate. The experiments use five traces of 37 to 185 days of client URL requests. Surprisingly, the criteria used by several proxy-server removal policies (LRU, Hyper-G, and a proposal by Pitkow and Recker) are among the worst performing criteria in our simulation; instead, replacing documents based on size maximizes hit rate in each of the studied workloads.\",\n \"Title: Using concept maps as a cross-language resource discovery tool for large documents in digital libraries\\nYear: 2005\\n\\nAbstract: Project Gutenburg, the Million Book Project, the Networked Digital Library of Theses and Dissertations, Amazon's book search service, and the recently announced collaboration of Google and leading libraries, all aim to make available large numbers of book-length objects, in a variety of languages. Traditional approaches to discovering a suitable book for a particular purpose have generally relied on catalog records, sometimes enhanced with abstracts. Full-text searching - popular, e.g., with legal and government documents $and passage retrieval techniques, suitable for encyclopedias and reference works, have not been adequately tested with large collections of large objects\",\n \"Title: Use of subimages in fish species identification: a qualitative study\\nYear: 2011\\n\\nAbstract: Many scholarly tasks involve working with subdocuments, or contextualized fine-grain information, i.e., with information that is part of some larger unit. A digital library (DL) facilitates management, access, retrieval, and use of collections of data and metadata through services. However, most DLs do not provide infrastructure or services to support working with subdocuments. Superimposed information (SI) refers to new information that is created to reference subdocuments in existing information resources. We combine this idea of SI with traditional DL services, to define and develop a DL with SI (SI-DL). We explored the use of subimages and evaluated the use of SuperIDR, a prototype SI-DL, in fish species identification, a scholarly task that involves working with subimages. The contexts and strategies of working with subimages in SuperIDR suggest new and enhanced support (SI-DL services) for scholarly tasks that involve working with subimages, including new ways of querying and searching for subimages and associated information. The main conceptual contributions of our work are the insights gained from these findings of the use of subimages and of SuperIDR, which lead to recommendations for the design of digital libraries with superimposed information.\",\n \"Title: NMFS: Network Multimedia File System Protocol\\nYear: 1992\\n\\nAbstract: We describe an on-going project to develop a Network Multimedia File System (NMFS) protocol. The protocol allows \\\"transparent access of shared files across networks\\\" as Sun''s NFS protocol does, but attempts to meet a real-time delivery schedule. NMFS is designed to provide ubiquitous service over networks both designed and not designed to carry multimedia traffic.\",\n \"Title: The role of digital libraries in moving toward knowledge environments\\nYear: 2005\\n\\nAbstract: For thousands of years, libraries have allowed humanity to collect and organize data and information, and to support the discovery and communication of knowledge, across time and space. Coming together in this Internet Age, the world's societies have extended this process to span from the personal to the global, as the concepts, practices, systems, and services related to Library and Information Science unfold through digital libraries. Scientists, scholars, teachers, learners, and practitioners of all kinds benefit from the distributed and collaborative knowledge environments that are at the heart of the digital library movement. Digital libraries thus encompass the dimensions in the 5S Framework: Societies, Scenarios, Spaces, Streams, and Structures. To clarify this approach, we explain the role of meta-models, such as of a minimal digital library (DL), and of more specialized (discipline-oriented) DLs, such as archeological DLs. We illustrate how suitable knowledge environments can be more easily prepared as instances of these meta-models, resulting in usable and useful DLs, including for education, computing, and archaeology.\",\n \"Title: Knowledge discovery in digital libraries of electronic theses and dissertations: an NDLTD case study\\nYear: 2008\\n\\nAbstract: Many scholarly writings today are available in electronic formats. With universities around the world choosing to make digital versions of their dissertations, theses, project reports, and related files and data sets available online, an overwhelming amount of information is becoming available on almost any particular topic. How will users decide which dissertation, or subsection of a dissertation, to read to get the required information on a particular topic? What kind of services can such digital libraries provide to make knowledge discovery easier? In this paper, we investigate these issues, using as a case study the Networked Digital Library of Theses and Dissertations (NDLTD), a rapidly growing collection that already has about 800,000 Electronic Theses and Dissertations (ETDs) from universities around the world. We propose the design for a scalable, Web Services based tool KDWebS (Knowledge Discovery System based on Web Services), to facilitate automated knowledge discovery in NDLTD. We also provide some preliminary proof of concept results to demonstrate the efficacy of the approach.\",\n \"Title: Effectiveness of implicit rating data on characterizing users in complex information systems\\nYear: 2005\\n\\nAbstract: Most user focused data mining techniques involve purchase pattern analysis, targeted at strictly-formatted database-like transaction records. Most personalization systems employ explicitly provided user preferences rather than implicit rating data obtained automatically by collecting users' interactions. In this paper, we show that in complex information systems such as digital libraries, implicit rating data can help to characterize users' research and learning interests, and can be used to cluster users into meaningful groups. Thus, in our personalized recommender system based on collaborative filtering, we employ a user tracking system and a user modeling technique to capture and store users' implicit ratings. Also, we describe the effects (on community finding) of using four different types of implicit rating data.\",\n \"Title: Mirroring an OAI archive on the I2-DSI channel\\nYear: 2002\\n\\nAbstract: The Open Archives Initiative (OAI) promotes interoperability among digital libraries and has created a protocol for data providers to easily export their metadata. One problem with this approach is that some of the more popular servers quickly become heavily loaded. The obvious solution is replication. Fortunately, the Internet-2 Distributed Storage Infrastructure (I2-DSI) has begun to develop technology for highly distributed transparent replication of servers. This paper presents our solution for transparent mirroring of OAI repositories within the I2-DSI.\",\n \"Title: ETANA-DL: a digital library for integrated handling of heterogeneous archaeological data\\nYear: 2004\\n\\nAbstract: Archaeologists have to deal with vast quantities of information, generated both in the field and laboratory. That information is heterogeneous in nature, and different projects have their own systems to store and use it. This adds to the challenges regarding collaborative research between such projects as well as information retrieval for other more general purposes. This paper describes our approach towards creating ETANA--DL, a digital library (DL) to help manage these vast quantities of information and to provide various kinds of services. The 5S framework for modeling a DL gives us an edge in understanding this vast and complex information space, as well as in designing and prototyping a DL to satisfy information needs of archaeologists and other user communities.\",\n \"Title: Combining structural and citation-based evidence for text classification\\nYear: 2004\\n\\nAbstract: This paper discusses how citation-based information and structural content (e.g., title, abstract) can be combined to improve classification of text documents into predefined categories. We evaluate different measures of similarity derived from the citation structure and the structural content of the collection, and determine how they can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our empirical experiments using documents from the ACM Digital Library and the ACM Computing Classification System show that we can discover similarity functions that work better than using evidence in isolation and whose combined performance through a simple majority voting is comparable to that of Support Vector Machine classifiers.\",\n \"Title: Connecting Topics in Document Collections with Stepping Stones and Pathways\\nYear: 2005\\n\\nAbstract: In this paper, we present Stepping Stones and Pathways (SSP), an alternative model of building and presenting answers for the cases when queries on document collections cannot be answered just by a ranked list. Stepping Stones can handle questions like: \\\"What is the relation of topics X and Y?\\\" SSP addresses when the contents of a small set of related documents is needed as an answer rather than a single document, or when \\\"query splitting\\\" is required to satisfactorily explore a document space. Query results are networks of document groups representing topics, each group relating to and connecting (by documents) to other groups in the network. Thus, a network answers the user's information need. We devise new and more effective representations and techniques to visualize such answers, and to involve users as part of the answer-finding process. In order to verify the validity of our approach, and since the questions we aim to answer involve multiple topics, we performed a study involving a custom built broad collection of operating systems research papers, and evaluated the results with interested computer science students, using multiple measures.\",\n \"Title: Advances in Interactive Digital Multimedia Systems\\nYear: 1991\\n\\nAbstract: This paper introduces basic concepts in digital multimedia systems and surveys recent literature. Background is provided regarding developments in interactive videodiscs, which first made images and video accessible through computer systems. Digital storage media, including optical, magnetic, and network options, are addressed. The characteristics of audio and video and their digital representations are discussed. Because these media are so demanding of space and channel bandwidth, compression methods are reviewed. Standards for digital multimedia are considered. Current multimedia systems are described, and future prospects are indicated.\",\n \"Title: Domain-specific image geocoding: a case study on Virginia tech building photos\\nYear: 2013\\n\\nAbstract: The use of map-based browser services is of great relevance in numerous digital libraries. The implementation of such services, however, demands the use of geocoded data collections. This paper investigates the use of image content local representations in geocoding tasks. Performed experiments demonstrate that some of the evaluated descriptors yield effective results in the task of geocoding VT building photos. This study is the first step to geocode multimedia material related to the VT April 16, 2007 school shooting tragedy.\",\n \"Title: Curriculum development for digital libraries\\nYear: 2006\\n\\nAbstract: The Virginia Tech Department of Computer Science (VT CS) and the University of North Carolina at Chapel Hill School of Information and Library Science (UNC SILS) have launched a curriculum development project in the area of digital libraries. Educational resources will be developed based on the ACM/IEEE-CS Computing Curriculum 2001. Lesson plans and modules will be developed in a variety of areas (that cover the topics of papers and conference sessions in the field), evaluated by experts in those areas, and then pilot tested in CS and LIS courses. An analysis of papers on digital library-related topics from several corpora was performed, to identify the areas in which more and less work has already been performed on these topics; this analysis will guide the initial stages of this curriculum development.\",\n \"Title: Ranking Function Discovery by Genetic Programming for Robust Retrieval\\nYear: 2003\\n\\nAbstract: Ranking functions are instrumental for the success of an information retrieval (search engine) system. However nearly all existing ranking functions are manually designed based on experience, observations and probabilistic theories. This paper tested a novel ranking function discovery technique proposed in (Fan 2003a, Fan2003b) - ARRANGER (Automatic geneRation of RANking functions by GEnetic pRogramming), which uses Genetic Programming (GP) to automatically learn the \\\"best\\\" ranking function, for the robust retrieval task. Ranking function discovery is essentially an optimization problem. As the search space here is not a coordinate system, most of the traditional optimization algorithms could not work. However, this ranking discovery problem could be easily tackled by ARRANGER. In our evaluations on 150 queries from the ad-hoc track of TREC 6, 7, and 8, the performance of our system (in average precision) was improved by nearly 16%, after replacing Okapi BM25 function with a function automatically discovered by ARRANGER. By applying pseudo-relevance feedback and ranking fusion on newly discovered functions, we improved the retrieval performance by up to 30%. The results of our experiments showed that our ranking function discovery technique - ARRANGER - is very effective in discovering high-performing ranking functions.\",\n \"Title: AI and Global Science and Technology Assessment\\nYear: 2009\\n\\nAbstract: Strength in science & technology (S&T) is the foundation of a nation's economic power, so an effective, automated means of continually assessing this strength is critical to understanding a country's economic status. Six essays on global S&T assessment present various research frameworks, computational methods, issues, and results relative to knowledge mapping, scientometrics, information visualization, digital libraries, and multilingual knowledge management.\",\n \"Title: Incremental, semi-automatic, mapping-based integration of heterogeneous collections into archaeological digital libraries: Megiddo case study\\nYear: 2005\\n\\nAbstract: Automation is an important issue when integrating heterogeneous collections into archaeological digital libraries. We propose an incremental approach through intermediary- and mapping-based techniques. A visual schema mapping tool within the 5S [1] framework allows semi-automatic mapping and incremental global schema enrichment. 5S also helped speed up development of a new multi-dimension browsing service. Our approach helps integrate the Megiddo [2] excavation data into a growing union archaeological DL, ETANA-DL [3].\",\n \"Title: Building a large thesaurus for information retrieval\\nYear: 1988\\n\\nAbstract: Information retrieval systems that support searching of large textual databases are typically accessed by trained search intermediaries who provide assistance to end users in bridging the gap between the languages of authors and inquirers. We are building a thesaurus in the form of a large semantic network to support interactive query expansion and search by end users. Our lexicon is being built by analyzing and merging data from several large English dictionaries; testing of its value for retrieval is with the SMART and CODER systems.\",\n \"Title: Incremental clustering for very large document databases: initial MARIAN experience\\nYear: 1995\\n\\nAbstract: Clustering of document databases is useful for both browsing and searching purposes; however, this can be a prohibitively expensive computational process for lai ge collections. This problem is compounded when the clustering structure must reflect a constantly changing database. Therefore, efficient algorithms which maintain an existing clustering structure are desirable, This study provides the details of a large-scale implementation of the Cover-Coefficient-based Incremental Clustering Methodology (C(2)ICM). The experiments performed on a sample of the MARIAN database show that its resource requirements are within practical bounds for most platforms. Furthermore, C(2)ICM offers considerable savings over reclustering. The results of this study will lead to an additional type of browsing and/or searching facility on the Virginia Tech-based MARIAN large online public access library catalog (OPAC) project.\",\n \"Title: Ensemble PDP-8: eight principles for distributed portals\\nYear: 2010\\n\\nAbstract: Ensemble, the National Science Digital Library (NSDL) Pathways project for Computing, builds upon a diverse group of prior NSDL, DL-I, and other projects. Ensemble has shaped its activities according to principles related to design, development, implementation, and operation of distributed portals. Here we articulate 8 key principles for distributed portals (PDPs). While our focus is on education and pedagogy, we expect that our experiences will generalize to other digital library application domains. These principles inform, facilitate, and enhance the Ensemble R&D and production activities. They allow us to provide a broad range of services, from personalization to coordination across communities. The eight PDPs can be briefly summarized as: (1) Articulation across communities using ontologies. (2) Browsing tailored to collections. (3) Integration across interfaces and virtual environments. (4) Metadata interoperability and integration. (5) Social graph construction using logging and metrics. (6) Superimposed information and annotation integrated across distributed systems. (7) Streamlined user access with IDs. (8) Web 2.0 multiple social network system interconnection.\",\n \"Title: Building interoperable digital library services: MARIAN, open archives, and the NDLTD\\nYear: 2001\\n\\nAbstract: In this demonstration, we present interoperable and personalized search services for the Networked Digital Library of Theses and Dissertations (NDLTD). Using standard protocols and software, including those specified by the Open Archives Initiative (OAI), distributed sites can share metadata easily. On top of these harvesting protocols, we implement a union collection of theses managed by the MARIAN digital library system. Our demonstration covers aspects of NDLTD, OAI, and MARIAN.\",\n \"Title: SIMPEL: a superimposed multimedia presentation editor and player\\nYear: 2006\\n\\nAbstract: Summary form only given. In a variety of applications such as learning, we need to integrate multimedia information into convenient packages. The challenges involved in this process are: selecting or working with information elements at sub-document level while retaining the original context; describing the integration or packaging of such elements; and making use of minimal storage during this activity. We developed the superimposed multimedia presentation editor and player (SIMPEL), a tool to address these challenges. SIMPEL allows a user to reference information of many types, at varying granularity, without replicating the referenced information. It also allows the user to compose synchronized multimedia presentations. SIMPEL is in a genre of applications called superimposed applications (SAs), which allow users to superimpose new interpretations over existing or base information. SAs employ \\\"marks\\\", references to selected regions within base information. SIMPEL uses the superimposed pluggable architecture for contexts and excerpts (SPARCE), middleware that provides mark management and other services for SAs. SIMPEL has been implemented for Windows in Visual Basic.NET and uses XML for storing presentation data\",\n \"Title: An OAI compliant content-based image search component\\nYear: 2004\\n\\nAbstract: Advances in data storage and image acquisition technologies haveenabled the creation of large image datasets In order to deal withthese data, appropriate information systems (e.g. image digital libraries) have been developed to efficiently manage such collections. One of the most common retrieval approaches is to employ so--called Content--Based Image Retrieval (CBIR) systems. Basically, these systems try to retrieve images similar to auser--defined pattern (e.g. image example). Their goal is to supportimage retrieval based on content properties (e.g. shape, color, or texture), which are often encoded in terms of imagedescriptors This demonstration presents a new CBIR system based on configurable components. The main novelty resides in its Content--Based ImageSearch Component (CBISC) that supports queries on image collections CBISC is based on the OAIprinciples, and thus provides an easy--to--install search engine tosupport querying images by content As with the OAI protocol, queriesare posed via HTTP requests and the responses are encoded in XML CBISC encapsulates multidimensional indexstructures to speed up the searchprocess. Furthermore, it supports the use of different imagedescriptors (metric and non--metric; color, texture, and shapedescriptors; with 1D or 2D feature vectors), which canbe easily combined to yield improved effectiveness. We will show thatthis search component can be tailored for particular image collectionsby a trained designer, who carries out a clearly defined set of pilot experiments to select the appropriate descriptors. Image descriptors are typically domain and usage--dependent Further, agiven image can be associated with very many descriptors However, standard CBIR methods only support a fixed set of descriptors CBISC, instead, allows progressive extension of thedescriptor base Figure 1 presents a screen shotshowing the CBISC Configuration Tool developed to support CBISC designers in the configuration process Basically, this processconcerns the description/definition of both the image descriptors thatwill be used to retrieve images by content, and the image database to which the CBISC is related The XML file generated in thisprocess is used during CBISC execution.\",\n \"Title: Twitter use during an emergency event: the case of the UT Austin shooting\\nYear: 2011\\n\\nAbstract: This poster presents one of our efforts in the context of the Crisis, Tragedy, and Recovery Network (CTRnet) project. One topic studied in this project is the use of social media by government to respond to emergency events in towns and counties. Monitoring social media information for unusual behavior can help identify these events once we can characterize their patterns. As an example, we analyzed the campus shooting in the University of Texas, Austin, on September 28, 2010. In order to study the pattern of communication and the information communicated using social media on that day, we collected publicly available data from Twitter. Collected tweets were analyzed and visualized using the Natural Language Toolkit, word clouds, and graphs. They showed how news and posts related to this event swamped the discussions of other issues.\",\n \"Title: Usability study of digital libraries: ACM, IEEE-CS, NCSTRL, NDLTD\\nYear: 1999\\n\\nAbstract: If digital libraries are to be used effectively, their user interfaces should be tested and enhanced. We observed 48 participants as they worked with the following digital libraries: ACM, IEEE-CS, NCSTRL, and NDLTD. We discuss how the features of these digital libraries influence the subjects' efforts to perform search and retrieval tasks. Data analysis indicates that the IEEE-CS digital library was rated the best overall and NDLTD had the best search time. We present user recommendations and propose a taxonomy of features that we believe are essential for the design of future digital libraries. Noteworthy is the observation that users' judgements on the importance of different features varied widely between the beginning and end of their test sessions.\",\n \"Title: Enhancing digital libraries and portals with canonical structures for complex objects\\nYear: 2012\\n\\nAbstract: Individual digital library resources are of interest in their own right, but, in some domains, resources can be part of (perhaps multiple) complex objects. We focus on domains with complex objects where a digital library user can benefit from seeing and browsing a resource in the context of its structure(s). We introduce canonical structures that can represent local digital library structures; the canonical structures allow us to provide sophisticated browsing/navigation aids in a generic way. We evaluate a means to transfer the structure of our resources to a digital library portal. We implement and evaluate approaches based on OAI-PMH and OAI-ORE using Dublin Core--with and without a custom namespace. We also transfer the canonical structure to a portal where our navigation widget is implemented.\",\n \"Title: Hard Queries can be Addressed with Query Splitting Plus Stepping Stones and Pathways\\nYear: 2005\\n\\nAbstract: A key finding of the Reliable Information Access Workshop of 2003 was that in collections like those used for TREC 6-8, there are a number of hard queries for which no current search engine can return a high quality set of results. Our Stepping Stones and Pathways (SSP) approach may yield an effective solution to such hard problems, as well as support exploration of collections of content not well known to a person (with broad interest and/or complex information needs). Our initial and promising testing of SSP had users prepare two separate short queries in order to launch processing. However, since beginning with a single information need is a more typical initial situation, we have extended the SSP research by exploring query splitting, especially as might apply to handling hard queries. This paper summarizes our recent results and identifies some of the future work needed.\",\n \"Title: Web Traffic Latency: Characteristics and Implications\\nYear: 1998\\n\\nAbstract: : It is critical to understand WWW latency in order to designbetter HTTP protocols. In this study we characterize Web response timeand examine the effects of proxy caching, network bandwidth, trafficload, persistent connections for a page, and periodicity. Based on studieswith four workloads, we show that at least a quarter of the total elapsedtime is spent on establishing TCP connections with HTTP/1.0. Thedistributions of connection time and elapsed time can be modeled usingPearson,...\",\n \"Title: Composite document extended retrieval: an overview\\nYear: 1985\\n\\nAbstract: Experimental information retrieval (IR) systems, some dating back to the sixties, have demonstrated the viability of fully automatic document storage and retrieval methodologies with small to medium size bibliographic collections [72]. Many of these experimental systems utilize the vector space model in which each important term (such as a word stem) identifies a different dimension in a space, so that matrix methods and vector operations can be defined on queries and documents. Statistical techniques have been very effective, and probabilistic enhancements have given additional improvements [84]. However, the basic vector space model is oriented towards recording the essential information in the text of a title/abstract combination rather than describing more complex document structures. It is necessary to extend the model in order to handle composite documents.On the other hand, commonly available retrieval systems that employ Boolean logic queries and utilize inverted file storage schemes can without modification accommodate such documents, albeit with somewhat less effectiveness than is possible with more sophisticated systems. Hence, it is also of interest to consider how Boolean logic systems can be extended to give better performance, especially with composite documents, and to integrate those approaches with vector methods.\",\n \"Title: CTRnet DL for disaster information services\\nYear: 2011\\n\\nAbstract: We describe our work in collecting, analyzing and visualizing online information (e.g., Web documents, images, tweets), which are to be maintained by the Crisis, Tragedy and Recovery Network (CTRnet) digital library. We have been collecting resources about disaster events, as well as campus and other major shooting events, in collaboration with the Internet Archive (IA). Social media data (e.g., tweets, Facebook data) also have been collected and analyzed. Analyzed results are visualized using graphs and tag clouds. Exploratory content-based image retrieval has been applied in one of our image collections. We explain our CTR ontology development methodology and collaboration with Arlington County, VA and IBM, in a Center for Community Security and Resilience funded project.\",\n \"Title: Integration of complex archeology digital libraries: An ETANA-DL experience\\nYear: 2008\\n\\nAbstract: In this paper, we formalize the digital library (DL) integration problem and propose an overall approach based on the 5S (streams, structures, spaces, scenarios, and societies) framework. We then apply that framework to integrate domain-specific (archeological) DLs, illustrating our solutions for key problems in DL integration. An integrated Archeological DL, ETANA-DL, is used as a case study to justify and evaluate our DL integration approach. More specifically, we develop a minimal metamodel for archeological DLs within the 5S theory. We implement the 5SSuite tool set to cover the process of union DL generation, including requirements gathering, conceptual modeling, rapid prototyping, and code generation. 5SSuite consists of 5SGraph, 5SGen, and SchemaMapper, each of which plays an important role in DL integration. We also propose an approach to integrated DLs based on the 5S formalism, which provides a systematic method to design and implement DL exploring services.\",\n \"Title: How educators find educational resources online\\nYear: 2011\\n\\nAbstract: Search engines are mostly targeted toward the generic user but educators have specific information needs with specialized information-seeking behaviors. When designing a course, educators may create a syllabus, lecture slides, and use tools as lecture aides. These resources are scattered across a large number of websites and require time and effort in finding them. To design a useful system for educators we must understand the problems they face when they seek, use, and re-use online resources. With that in mind, the Ensemble team conducted focus groups to identify current practices and problems in locating online resources for educational purposes. The data provides better understanding of the information-seeking process of educators that can lead to better educational resource sites.\",\n \"Title: CRIM: curricular resources in interactive multimedia\\nYear: 1999\\n\\nAbstract: The CRIM project addresses the need for curricular guidelines and educational resources for the Interactive Multimedia area. A digital library / repository allows educators to submit knowledge modules that will be reviewed and made available for use by teachers or students. Recommendations are given for courses and topics, and a process is outlined to reach consensus and improve education. This efforts is connected with the Computer Science Teaching Center, http://www.cstc.org/.\",\n \"Title: Envision: a user-centered database of computer science literature\\nYear: 1995\\n\\nAbstract: Project Envision is an early NSF-funded digital library effort to develop a multimedia collection of computer science literature with full-text searching and full-content retrieval capabilities. Envision was launched in 1991 in accordance with the ACM Publications Board's plans for encouraging research studies to develop an electronic archive for computer science.\",\n \"Title: A faster algorithm for constructing minimal perfect hash functions\\nYear: 1992\\n\\nAbstract: Our previous research on one-probe access to large collections of data indexed by alphanumeric keys has produced the first practical minimal perfect hash functions for this problem. Here, a new algorithm is described for quickly finding minimal perfect hash functions whose specification space is very close to the theoretical lower bound, i.e., around 2 bits per key. The various stages of processing are detailed, along with analytical and empirical results, including timing for a set of over 3.8 million keys that was processed on a NeXTstation in about 6 hours.\",\n \"Title: A study of user behavior in an immersive virtual environment for digital libraries\\nYear: 2000\\n\\nAbstract: In this paper we present a 2x3 factorial design study evaluating the limits and differences on the behavior of 10 users when searching in a virtual reality representation that mimics the arrangement of a traditional library. The focus of this study was the effect of clustering techniques and query highlighting on search strategy users develop in the virtual environment, and whether position or spatial arrangement influenced user behavior. We found several particularities that can be attributed to the differences in the VR environment.This study's results identify: 1) the need of co-designing both spatial arrangement and interaction method; 2) adifficulty novice users faced when using clusters to identify commontopics; 3) the influence of position and distance on users' selection of collection items to inspect; and 4) that users did not search until found the best match, but only until they found a satisfactory match.\",\n \"Title: Web Response Time and Proxy Caching\\nYear: 1998\\n\\nAbstract: It is critical to understand WWW latency in order to design better HTTP protocols. In this paper we characterize Web response time and examine effects of proxy caching on response time. We show that at least a quarter of the total elapsed time is spent in setting up TCP connections. We also characterize the effect of a user''s network bandwidth on response time. Average connection time from a client via a 33.6 K modem is two times longer than that from a client via switched Ethernet. Contrary to the typical thought about Web proxy caching, this study finds that a single stand alone proxy cache does not always reduce response time. Implications of these results to the HTTP-NG protocol and Web application design also are discussed in the paper.\",\n \"Title: Digital library education in computer science programs\\nYear: 2007\\n\\nAbstract: In an effort to identify the \\\"state of the art\\\" in digital library education in computer science (CS) programs, we analyzed CS courses on digital libraries and digital library-related topics. Fifteen courses that mention digital libraries in the title or short description were identified; of these, five are concerned with digital libraries as the primary topic of the course. The readings from these five courses were analyzed further, in terms of their authors and the journals in which they were published.\",\n \"Title: Intelligent GP fusion from multiple sources for text classification\\nYear: 2005\\n\\nAbstract: This paper shows how citation-based information and structural content (e.g., title, abstract) can be combined to improve classification of text documents into predefined categories. We evaluate different measures of similarity -- five derived from the citation information of the collection, and three derived from the structural content -- and determine how they can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our experiments with the ACM Computing Classification Scheme, using documents from the ACM Digital Library, indicate that GP can discover similarity functions superior to those based solely on a single type of evidence. Effectiveness of the similarity functions discovered through simple majority voting is better than that of content-based as well as combination-based Support Vector Machine classifiers. Experiments also were conducted to compare the performance between GP techniques and other fusion techniques such as Genetic Algorithms (GA) and linear fusion. Empirical results show that GP was able to discover better similarity functions than GA or other fusion techniques.\",\n \"Title: Coefficients of combining concept classes in a collection\\nYear: 1988\\n\\nAbstract: This report considers combining information to improve retrieval. The vector space model has been extended so different classes of data are associated with distinct concept types and their respective subvectors. Two collections with multiple concept types are described, ISI-1460 and CACM-3204. Experiments indicate that regression methods can help predict relevance, given query-document similarity values for each concept type. After sampling and transformation of data, the coefficient of determination for the best model was .48 (.66) for ISI (CACM). Average precision for the two collections was 11% (31%) better for probabilistic feedback with all types versus with terms only. These findings may be of particular interest to designers of document retrieval or hypertext systems since the role of links is shown to be especially beneficial.\",\n \"Title: Development of the CODER system: a testbed for artificial intelligence methods in information retrieval\\nYear: 1987\\n\\nAbstract: The CODER ( Co mposite D ocument E xpert/Extended/Effective R etrieval) system is a testbed for investigating the application of artificial intelligence methods to increase the effectiveness of information retrieval systems. Particular attention is being given to analysis and representation of heterogeneous documents, such as electronic mail digests or messages, which vary widely in style, length, topic, and structure. Since handling passages of various types in these collections is difficult even for experimental systems like SMART, it is necessary to turn to other techniques being explored by information retrieval and artificial intelligence researchers. The CODER system architecture involves communities of experts around active blackboards, accessing knowledge bases that describe users, documents, and lexical items of various types. The initial lexical knowledge base construction work is now complete, and experts for search and time/date handling can perform a variety of processing tasks. User information and queries are being gathered, and a simple distributed skeletal system is operational. It appears that a number of artificial intelligence techniques are needed to best handle such common but complex document analysis and retrieval tasks.\",\n \"Title: Multilingual Federated Searching Across Heterogeneous Collections\\nYear: 1998\\n\\nAbstract: This article describes a scalable system for searching heterogeneous multilingual collections on the World Wide Web. It details a markup language for describing the characteristics of a search engine and its interface, and a protocol for requesting word translations between languages.\",\n \"Title: Deduced social networks for an educational digital library\\nYear: 2012\\n\\nAbstract: By analyzing the behavior of previous users, digital libraries can be made to provide new users with more support to find the best information. The AlgoViz Portal collects metadata on algorithm visualizations and associated research literature. We show how logs can be used to discover latent relationships between users, deducing an implicit social network. By clustering the log data, we find different page-viewing patterns, which provide practical information about the different groups of users.\",\n \"Title: Prototyping Digital Libraries Handling Heterogeneous Data Sources - The ETANA-DL Case Study.\\nYear: 2004\\n\\nAbstract: Information systems used in archaeology have several needs: interoperability among heterogeneous systems, making information available without significant delay, long-term preservation of data, and providing a suite of services to users. In this paper, we show how digital library techniques can be employed to provide solutions to three of these problems. We show this by describing a prototype for an archaeological Digital Library (ETANA-DL). First, ETANA-DL applies and extends the metadata harvesting approach to address some of the needs-interoperability, rapid access to data, and data preservation. Second, we show that availability of a pool of components that implement common DL services has helped in rapidly creating the prototype, which was subsequently used for requirements elicitation. However, understanding complex archaeological information systems is a difficult task. Third, therefore, we describe our efforts to model these systems using the 5S framework, and show how the partially developed model has been used to implement complex services helping users carry out key tasks with the integrated data.\",\n \"Title: Development of a modern OPAC: from REVTOLC to MARIAN\\nYear: 1993\\n\\nAbstract: Since 1986 we have investigated the problems and possibilities of applying modern information retrieval methods to large online public access library catalogs (OPACs). In the Retrieval Experiment—Virginia Tech OnLine Catalog (REVTOLC) study we carried out a large pilot test in 1987 and a larger, controlled investigation in 1990, with 216 users and roughly 500,000 MARC records. Results indicated that a forms-based interface coupled with vector and relevance feedback retrieval methods would be well received. Recent efforts developing the Multiple Access and Retrieval of Information with Annotations (MARIAN) system have involved used of a specially developed object-oriented DBMS, construction of a client running under NeXTSTEP, programming of a distributed server with a thread assigned to each user session to increase concurrency on a small network of NeXTs, refinement of algorithms to use objects and stopping rules for greater efficiency, usability testing and iterative interface refinement.\",\n \"Title: Multiple sources with multiple portals: a demonstration of the ensemble computing portal in second life\\nYear: 2010\\n\\nAbstract: This demonstration is an overview of our Ensemble pathway project with group members on-location at the conference and in the virtual world of Second Life from remote locations providing a live walk-through tour of our project online. This approach allows the demonstration to extend beyond the allocated conference session as a means to attract people to JCDL/ICADL.\",\n \"Title: Categorization of computing education resources with utilization of crowdsourcing\\nYear: 2012\\n\\nAbstract: The Ensemble Portal harvests resources from multiple heterogeneous federated collections. Managing these dynamically increasing collections requires an automatic mechanism to categorize records in to corresponding topics. We propose an approach to use existing ACM DL metadata to build classifiers for harvested resources in the Ensemble project. We also present our experience with utilizing the Amazon Mechanical Turk platform to build ground truth training data sets from Ensemble collections.\",\n \"Title: Citiviz: A Visual User Interface to the CITIDEL System.\\nYear: 2004\\n\\nAbstract: The Digital Library (DL) field is one of the most promising areas of application for information visualization technology. In this paper, we propose a visual user interface tool kit for digital libraries, to deliver an overview of document sets, with support for interactive direct manipulation. Our system, Citiviz, employs a dynamic hyperbolic tree to display hierarchical relationships among documents, based on where their topics fit into the ACM classification system. Also, Citiviz provides an interactive, animated 2-dimensional scatter plot. With it, users may gain insight by changing various parameters, or may directly jump to a particular document based on its label or location. According to a preliminary evaluation, our system shows advantages in performance and user preference relative to traditional text based DL web interfaces.\",\n \"Title: A library of reusable model components for visual simulation of the NCSTRL system\\nYear: 1998\\n\\nAbstract: This paper presents a library of reusable model components for visual simulation of the Networked Computer Science Technical Report Library (NCSTRL) and illustrates how a visual simulation model can be developed for a new NCSTRL configuration by way of component reuse with no programming. Such a repository of reusable model components can be created for visual simulation of any digital library for the purpose of performance evaluation and tuning and conducting what-if analyses for different system design configurations.\",\n \"Title: Support Vector Machines to Weight Voters in a Voting System of Entity Extractors\\nYear: 2006\\n\\nAbstract: Support vector machines are used to combine the outputs of multiple entity extractors, thus creating a composite entity extraction system. The composite system has a significantly higher f-measure than any of the component systems. Compared to a standard voting technique for combining the results of multiple entity extractors, the SVM approach produces comparable precision and recall statistics but tends to utilize fewer of the component entity extractors, thus providing superior computational efficiency, which is critical in practical applications. In this paper, we present our experimental results of comparing a standard voting technique with SVM that each aggregate four entity extractors. We also describe our future plans of integrating agent-based technology into our experimental testbed where we examine the evolution of composite techniques as part of the analysis stream. Given that much of the improvement comes from tuning the algorithms to the data stream with a human-in-the-loop, we are considering the merits of employing cognitive agents that are strategically embedded in the workflow for processing data. As we tune the algorithms for better performance on the data streams, we envision agents learning the patterns of data streams and apply the appropriate tuning to ensure optimality.\",\n \"Title: Enhancing the ENVISION interface for digital libraries\\nYear: 2002\\n\\nAbstract: To enhance the ENVISION interface and facilitate user interaction, various techniques were considered for better rendering of search results with improved scalability. In this paper we discuss the challenges we encountered and our solutions to those problems.\",\n \"Title: Hypermedia support for a digital library in CS\\nYear: 1995\\n\\nAbstract: Since 1991 we have been developing a digital library (DL) in computer science and applying if for CS education. NSF has founded two large projects focusing in this area, as well as several related efforts. \\\"A User-Centered Database for the Computer Science Literature\\\" ran from 1991 through early 1995, benefited from strong support from ACM, and led to the Envision system [8, 9, 10]. \\\"Interactive Learning With a Digital Library in Computer Science\\\" [6, 7] runs from 1993 through early 1997, is supported by ACM as well as other publishers like IEEE-CS, includes efforts at Norfolk State University (NSU), and benefits from extensive hypermedia system support. By late April 1995, thirteen courses were supported by this El (NSF Education Infrastructure) project and over forty thousand accesses a week were logged by our server.\",\n \"Title: Specification and generation of digital libraries into DSpace using the 5S framework\\nYear: 2007\\n\\nAbstract: While digital library (DL) systems continue to become more powerful and usable, a certain amount of inherent complexity remains in the installation, configuration, and customization of out-of-the-box solutions like DSpace and Greenstone. In this work, we build upon past work in the 5S Framework for Digital Libraries and 5SL DL specification language to devise an XML-based model for the specification of DLs for DSpace. We pair this way of specifying DLs with a generator tool which takes a DL specification that adheres to the model and generates a working DSpace instance that matches the specification.\",\n \"Title: Species identification: fish images with CBIR and annotations\\nYear: 2009\\n\\nAbstract: Fish species identification is critical to the study of fish ecology and management of fisheries. However, learning to identify fish is difficult for Ichthyology students. Traditionally, dichotomous keys are used for fish identification. They ask questions about the observed specimen, and then, based on the answer, ask more questions until the specimen is identified. This rigid approach does not accommodate the range of learning styles actually utilized by Ichthyology students. Further, keys often differ from distinguishing characteristics of fishes such as \\\"spinous dorsal fin\\\", \\\"forked tail\\\", \\\"large eye\\\", etc. This leads students to supplement the use of keys with other methods such as making personal notes and drawings, annotating fish images, and more recently, using fish information websites, such as Fishbase. Although these methods provide useful additional content, this content is dispersed across heterogeneous sources and can be tedious to manage and access. From a digital library (DL) perspective, we believe that electronic support for fish species identification can be improved considerably to address some of the aforementioned problems. There are many issues to consider, including better support for: 1) describing and accessing fish images; 2) easily managing and accessing user created content, especially that related to parts of images such as markings on drawings and images and associated notes; 3) easily sharing all of this information with others; and 4) a well-integrated solution, providing all of the above listed capabilities. Digital libraries researchers have been working on providing such integrated support for managing and accessing multimedia along with user created content, including annotating digital objects. We are working toward general solutions for DLs, running on popular platforms including DSpace and Fedora, and allowing those in a wide range of disciplines to \\\"mark\\\" important parts of digital objects, connect annotations with them, and manage the annotations inside the DL so that users can browse, search, and have objects rendered in the right environment with appropriate annotations. We developed SuperIDR, a small DL with image description and retrieval, providing such integrated support. SuperIDR. enables a user to add content in the form of image markings and annotations. In addition, it provides improved image searching: 1) through text-based search on species descriptions and annotations, where the query could be terms, phrases, or their boolean combination; or 2) through content-based image search on images and annotated-image-marks, where the query could be a complete image or part of an image. Finally, in SuperIDR, a user can browse through species information either through a taxonomic organization of species based on family and genera, or through an electronic version of the dichotomous key. In order to assess the effectiveness of SuperIDR as an aid to species identification, we conducted an experiment in an undergraduate Ichthyology class, where we compared the use of SuperIDR with traditional methods of species identification (either by using the key, personal notes, markings on images, use of websites, notecards, etc., or a combination of the aforementioned methods). We found that students identified more unknown fish specimens correctly with SuperIDR than with traditional methods. Through statistical analysis of sample data, we were able to conclude that the use of SuperIDR yielded a higher likelihood of success in species identification than does the use of traditional methods. We have made improvements to SuperIDR based on feedback received, and will be making it available to download. A natural extension of this system is to make it web-enabled, thus supporting content-sharing across data and user (social) networks. We used fish species identification as the specific scholarly task to situate our research ideas. However, we believe that our work is applicable to any scholarly task/domain involving images with a significant number of details, such as analyzing paintings in art history, examining a building style in architecture, understanding trees in dendrology, etc.\",\n \"Title: Tuning before feedback: combining ranking discovery and blind feedback for robust retrieval\\nYear: 2004\\n\\nAbstract: Both ranking functions and user queries are very important factors affecting a search engine's performance. Prior research has looked at how to improve ad-hoc retrieval performance for existing queries while tuning the ranking function, or modify and expand user queries using a fixed ranking scheme using blind feedback. However, almost no research has looked at how to combine ranking function tuning and blind feedback together to improve ad-hoc retrieval performance. In this paper, we look at the performance improvement for ad-hoc retrieval from a more integrated point of view by combining the merits of both techniques. In particular, we argue that the ranking function should be tuned first, using user-provided queries, before applying the blind feedback technique. The intuition is that highly-tuned ranking offers more high quality documents at the top of the hit list, thus offers a stronger baseline for blind feedback. We verify this integrated model in a large scale heterogeneous collection and the experimental results show that combining ranking function tuning and blind feedback can improve search performance by almost 30% over the baseline Okapi system.\",\n \"Title: A Framework for Building Open Digital Libraries\\nYear: 2001\\n\\nAbstract: Digital Libraries (DLs) have traditionally been positioned at the intersection of library science, computer science, and networked information systems. The different underlying philosophies of these three fields has had an unsettling influence on the development of DLs. While library science is fairly mature, networked information systems are constantly evolving to keep pace with Internet innovation. DLs are thus expected to demonstrate the careful management of libraries while supporting standards that evolve at an astonishing pace. This architectural moving target is a predicament that all DLs face sooner or later in their lifecycle, and one that few manage to deal with effectively. To exacerbate this problem, there has been a general desire for systems to be interoperable at the levels of data exchange and service collaboration. Such interoperability requirements necessitated the development of standards such as the Dublin Core Metadata Element Set and the Open Archives Initiative's Protocol for Metadata Harvesting (OAI-PMH). These standards have achieved a degree of success in the DL community largely because of their generality and simplicity. Informed by those lessons, this project is an attempt to consistently extend known interoperability standards to form the basis of a framework of components for building extensible DLs.\",\n \"Title: Using digital library components for biodiversity systems\\nYear: 2004\\n\\nAbstract: Biodiversity information systems (BISs) involve all kinds of heterogeneous data, which include ecological and geographical features However, available information systems offer very limited support for managing such data in an integrated fashion, and such integration is often based on geographic coordinates alone. Furthermore, such systems do not fully support image content management (e.g. photos of landscapes or living organisms), a requirement of many BIS end--users. In order to meet their needs, these users -- e.g. biologists, environmental experts -- often have to alternate between distinct biodiversity and image information systems to combine information extracted from them. This cumbersome operational procedure is forced on users by lack of interoperability among these systems. This hampers the addition of new data sources, as well as cooperation among scientists. The approach provided in this project to meet these issues is based on taking advantage of advances in Digital Library (DL) innovations to integrate networked collections of heterogeneous data. It focuses on creating the basis for a biodiversity information system under the digital library perspective, combining new techniques of content--based image retrieval and database query processing mechanisms. This approach solves the problem of system switching, and provides users with a flexible platform from which to tailor a BIS to their needs. The main contributions of this project are the following: (a) a generic architecture for managing heterogeneous collections, based ondigital library components, to access heterogeneous biodiversity data sources (text and images), that allows combining text--based andcontent--based queries in a seamless way; and (b) a new component, for content--based image search, integrated into that architecture. The proposed architecture has been implemented by using DL components which are mostly new or recently developed. Furthemore, its implementation uses the Open Archives Initiative (OAI) protocol as a basis for interoperability. This architecture is easily extensible, and provides users a considerable degree of flexibility in data management. To illustrate our claim that this architecture can be applied to several domains, we are investigating its application in building a biodiversity information system on fish species. This solution solves many current problems in this kind of system, allowing handling of images and textual information in an integrated fashion. A new Content-Based Image Search Component has been developed to support queries on image collections. Since this component is based onthe OAI principles, it provides an easy-to-install search engine toquery images by content. It can be readily tailored for a particular collection by a trained designer, who carries out a clearly definedset of pilot experiments. It supports the use of different image descriptors, which can be chosen from the pilot experiment, and theneasily combined to yield improved effectiveness. In addition, it encapsulates a multidimensional index structure to speed up the search process, that also can be easily configured for different image collections.\",\n \"Title: A digital library framework for biodiversity information systems\\nYear: 2006\\n\\nAbstract: Biodiversity Information Systems (BISs) involve all kinds of heterogeneous data, which include ecological and geographical features. However, available information systems offer very limited support for managing these kinds of data in an integrated fashion. Furthermore, such systems do not fully support image content (e.g., photos of landscapes or living organisms) management, a requirement of many BIS end-users. In order to meet their needs, these users--e.g., biologists, environmental experts--often have to alternate between separate biodiversity and image information systems to combine information extracted from them. This hampers the addition of new data sources, as well as cooperation among scientists. The approach provided in this paper to meet these issues is based on taking advantage of advances in digital library innovations to integrate networked collections of heterogeneous data. It focuses on creating the basis for a next-generation BIS, combining new techniques of content-based image retrieval and database query processing mechanisms. This paper shows the use of this component-based architecture to support the creation of two tailored BIS systems dealing with fish specimen identification using search techniques. Experimental results suggest that this new approach improves the effectiveness of the fish identification process, when compared to the traditional key-based method.\",\n \"Title: Designing Protocols in Support of Digital Library Componentization\\nYear: 2002\\n\\nAbstract: Reusability always has been a controversial topic in Digital Library (DL) design. While componentization has gained momentum in software engineering in general, there has not been broad DL standardization in component interfaces. Recently, the Open Archives Initiative (OAI) has begun to address this by creating a standard protocol for accessing metadata archives. We propose that the philosophy and approach adopted by the OAI can be extended easily to support inter-component protocols. In particular, we propose building DLs by connecting small components that communicate through a family of lightweight protocols, using XML as the data interchange mechanism. In order to test the feasibility of this, a set of protocols was designed based on the work of the OAI. Components adhering to these protocols were implemented and integrated into production and research DLs. The performance of these components was analyzed from the perspective of execution speed, network traffic, and data consistency. On the whole, this work has shown promise in the approach of applying the fundamental concepts of the OAI protocol to the task of DL component design and implementation.\",\n \"Title: Shared User Behavior on the World Wide Web\\nYear: 1997\\n\\nAbstract: Abstract: Studying accesses to Web servers from different user communities,helps identify similarities and differences in user access patterns. In this paper we identify invariants that hold across a collection of ten traces representing traffic seen by proxy servers. The traces were collected from university, high school, governmental, industry, and online service provider environments, with request rates that range from a few accesses to thousands of accesses per hour. In most of the workloads,a small portion of the clients are responsible for most of the accesses. In addition most of the accesses go to a small set of servers. By doing a longitudinal study on the collected data we noticed that the identified invariants do not change over a year period. However, the percentage of script generated documents, is increasing.\",\n \"Title: Developing a concept extraction technique with ensemble pathway\\nYear: 2011\\n\\nAbstract: In this paper, we describe our Concept Extraction technique for Educational Digital libraries (CEED) which applies Conditional Random Fields (CRFs) to extract concepts from the Ensemble Pathway collection. In addition, we discuss how we implement RESTful APIs for concept extraction.\",\n \"Title: Report on the workshop on web archiving and digital libraries (WADL 2013)\\nYear: 2013\\n\\nAbstract: This workshop explored the integration of Web archiving and digital libraries, so the complete life cycle involved is covered, from creation/authoring, uploading/publishing in the Web (including Web 2.0), (focused) crawling, curation, indexing, exploration (including searching and browsing), (text) analysis, archiving, and up through long-term preservation. It included particular coverage of current topics of interest: challenges facing archiving initiatives, archiving related to disasters, interaction with and use of archive data, applications on an international scale, working with big data, mobile Web archiving, temporal issues, Memento, and SiteStory.\",\n \"Title: Building Digital Libraries Made Easy: Toward Open Digital Libraries\\nYear: 2002\\n\\nAbstract: Digital libraries (DLs) promote a sharing culture among those who contribute and those who use resources. This same approach works when building Open Digital Libraries (ODLs). Leveraging the intellectual and practical investment made in the Open Archives Initiative through an eXtended Protocol for Metadata Harvesting (XPMH), one can build lightweight protocols to tie together key components that together make up the core of a DL. DL developers in various settings have learned how to apply this framework in a few hours. The ODL approach has been effective with the Computer Science Teaching Center (www.cstc.org), the Networked Digital Library of Theses and Dissertations (www.ndltd.org), and AmericanSouth.org. Hence, to support our Computing and Information Technology Interactive Digital Educational Library (www.citidel.org) and to provide a generic capability for other parts of the US National Science, technology, engineering, and mathematics education Digital Library (www.nsdl.org), we are developing a \\\"DL-in-a-box\\\" toolkit. When lightweight protocols, pools of components, and open standard reference models are combined carefully, as suggested in the OCKHAM discussions, both the DL user and developer communities can benefit from the principle of sharing.\",\n \"Title: What is a successful digital library?\\nYear: 2006\\n\\nAbstract: We synthesize diverse research in the area of digital library (DL) quality models, information systems (IS) success and adoption models, and information-seeking behavior models, to present a more integrated view of the concept of DL success. Such a multi-theoretical perspective, considering user community participation throughout the DL development cycle, supports understanding of the social aspects of DLs and the changing needs of users interacting with DLs. It also helps in determining when and how quality issues can be measured and how potential problems with quality can be prevented.\",\n \"Title: The Evolution of Scholarly Digital Library Needs in an International Environment: Social Reference Management Systems and Qatar\\nYear: 2013\\n\\nAbstract: Qatar has become an active research producer of data, publications, and other scholarly works. We studied the evolving scholarly activities and needs of researchers in this relatively new research environment, and compared them with previous findings from a well-established environment in the United States. The initial findings shed some light on the similarities and differences in information seeking behavior and information needs. We also highlighted some requirements and solutions appropriate for future international digital libraries and social reference management systems.\",\n \"Title: CINET: A cyberinfrastructure for network science\\nYear: 2012\\n\\nAbstract: Networks are an effective abstraction for representing real systems. Consequently, network science is increasingly used in academia and industry to solve problems in many fields. Computations that determine structure properties and dynamical behaviors of networks are useful because they give insights into the characteristics of real systems. We introduce a newly built and deployed cyberinfrastructure for network science (CINET) that performs such computations, with the following features: (i) it offers realistic networks from the literature and various random and deterministic network generators; (ii) it provides many algorithmic modules and measures to study and characterize networks; (iii) it is designed for efficient execution of complex algorithms on distributed high performance computers so that they scale to large networks; and (iv) it is hosted with web interfaces so that those without direct access to high performance computing resources and those who are not computing experts can still reap the system benefits. It is a combination of application design and cyberinfrastructure that makes these features possible. To our knowledge, these capabilities collectively make CINET novel. We describe the system and illustrative use cases, with a focus on the CINET user.\",\n \"Title: Intelligent fusion of structural and citation-based evidence for text classification\\nYear: 2005\\n\\nAbstract: This paper shows how different measures of similarity derived from the citation information and the structural content (e.g., title, abstract) of the collection can be fused to improve classification effectiveness. To discover the best fusion framework, we apply Genetic Programming (GP) techniques. Our experiments with the ACM Computing Classification Scheme, using documents from the ACM Digital Library, indicate that GP can discover similarity functions superior to those based solely on a single type of evidence. Effectiveness of the similarity functions discovered through simple majority voting is better than that of content-based as well as combination-based Support Vector Machine classifiers. Experiments also were conducted to compare the performance between GP techniques and other fusion techniques such as Genetic Algorithms (GA) and linear fusion. Empirical results show that GP was able to discover better similarity functions than other fusion techniques.\",\n \"Title: A digital library for water main break identification and visualization\\nYear: 2012\\n\\nAbstract: This paper describes a prototype of a digital library for water main break identification and visualization. Many utilities rely on an emergency call to detect water main breaks, because breaks are difficult to predict. Collecting the information by call requires time consuming human efforts. Furthermore, it is not archived and not shared with others. Collecting and archiving the information by tweets, news, and web resources helps users to identify relevant water main breaks efficiently. In developing this prototype, we extracted location information from text instead of using GPS data. We also describe the importance of tweet visualization by location, and how we visualize tweets on a map.\",\n \"Title: Hybrid Partition Inverted Files: Experimental Validation\\nYear: 2002\\n\\nAbstract: The rapid increase in content available in digital forms gives rise to large digital libraries, targeted to support millions of users and terabytes of data. Efficiently retrieving information then is a challenging task due to the size of the collection and its index. In this paper, our high performance \\\"hybrid\\\" partition inverted index is validated through experiments with a 100 Gbyte collection from TREC-9 and -10. The hybrid scheme combines the term and the document approaches to partitioning inverted indices across nodes of a parallel system. Experiments on a parallel system show that this organization outperforms the document and the term partitioning schemes. Our hybrid approach should support highly efficient searching for information in a large-scale digital library, implemented atop a network of computers.\",\n \"Title: Superimposed image description and retrieval for fish species identification\\nYear: 2009\\n\\nAbstract: Fish species identification is critical to the study of fish ecology and management of fisheries. Traditionally, dichotomous keys are used for fish identification. The keys consist of questions about the observed specimen. Answers to these questions lead to more questions till the reader identifies the specimen. However, such keys are incapable of adapting or changing to meet different fish identification approaches, and often do not focus upon distinguishing characteristics favored by many field ecologists and more user-friendly field guides. This makes learning to identify fish difficult for Ichthyology students. Students usually supplement the use of the key with other methods such as making personal notes, drawings, annotated fish images, and more recently, fish information websites, such as Fishbase. Although these approaches provide useful additional content, it is dispersed across heterogeneous sources and can be tedious to access. Also, most of the existing electronic tools have limited support to manage user created content, especially that related to parts of images such as markings on drawings and images and associated notes. We present SuperIDR, a superimposed image description and retrieval tool, developed to address some of these issues. It allows users to associate parts of images with text annotations. Later, they can retrieve images, parts of images, annotations, and image descriptions through text- and content-based image retrieval. We evaluated SuperIDR in an undergraduate Ichthyology class as an aid to fish species identification and found that the use of SuperIDR yielded a higher likelihood of success in species identification than using traditional methods, including the dichotomous key, fish web sites, notes, etc.\",\n \"Title: A Connection-Centric Survey of Recommender Systems Research\\nYear: 2002\\n\\nAbstract: Recommender systems attempt to reduce information overload and retain customers by selecting a subset of items from a universal set based on user preferences. While research in recommender systems grew out of information retrieval and filtering, the topic ha s steadily advanced into a legitimate and challenging research area of its own. Recommender systems have traditionally been studied from a content-based filtering vs. collaborative design perspective. Recommendations, however, are not delivered within a vacuum, but rather cast within an informal community of users and social context. Therefore, ultimately all recommender systems make connections among people and thus should be surveyed from such a perspective. This viewpoint is under- emphasized in the recommender systems literature. We therefore take a connection-oriented viewpoint toward recommender systems research. We posit that recommendation has an inherently social element and is ultimately intended to connect people either directly as a result of exp licit user modeling or indirectly through the discovery of relationships implicit in extant data. Thus, recommender systems are characterized by how they model users to bring people together: explicitly or implicitly. Finally, user modeling and the connection-centric viewpoint raise broadening and social issues—such as evaluation, targeting, and privacy and trust—which we also briefly address.\",\n \"Title: An Asian digital libraries perspective\\nYear: 2005\\n\\nAbstract: This introduces a special issue of IP&M that covers some of the best works from the International Conference on Asian Digital Libraries, 2002. Eight papers, from eight countries, cover a broad range of topics and themes. Many present models, algorithms, systems, and/or experiments. There are approaches based on probability theory, linguistics, user-centered design, and multimedia technologies. It is hoped that readers will apply key results, and participate in future ICADL events.\",\n \"Title: Use and usability in a digital library search system\\nYear: 1999\\n\\nAbstract: Digital libraries must reach out to users from all walks of life, serving information needs at all levels. To do this, they must attain high standards of usability over an extremely broad audience. This paper details the evolution of one important digital library component as it has grown in functionality and usefulness over several years of use by a live, unrestricted community. Central to its evolution have been user studies, analysis of use patterns, and formative usability evaluation. We extrapolate that all three components are necessary in the production of successful digital library systems.\",\n \"Title: Report on the NSF major educational funding initiative for a National Science, Technology, Engineering, and Mathematics Education Digital Library (NSDL) with special emphasis on the Computing Education component\\nYear: 2003\\n\\nAbstract: The NSDL consists of collections of materials accessible online, as well as many tools and services intended to enhance learning. Tools and services will support students and as well as faculty. This session will provide a status report on the state of the NSDL, its content, tools, and services. The session includes specific presentations of several services included in the NSDL. Session attendees discuss current and proposed initiatives, and offer suggestions about needs of highest priority.\",\n \"Title: MARIAN: Flexible Interoperability for Federated Digital Libraries\\nYear: 2001\\n\\nAbstract: Federated digital libraries are composed of distributed, autonomous, and often heterogeneous information services but provide users with a transparent, integrated view of collected information. In this paper we discuss a federated system for the Networked Digital Library of Theses and Dissertations (NDLTD), an international consortium of universities, libraries, and other supporting institutions focused on electronic theses and dissertations (ETDs). Federation requires dealing flexibly with differences among systems, ontologies, and data formats while respecting information sources' autonomy. Our solution involves adapting the object-oriented digital library system MARIAN to serve as mediation middleware for the federated NDLTD collection. Components of the solution include: 1) the use and integration of several harvesting techniques; 2) an architecture based on object-oriented ontologies of search modules and metadata; 3) reconciliation of diversity within the harvested data joined to a single collection view for the user; and 4) an integrated framework for addressing such questions as data quality, flexible and efficient search, and scalability.\",\n \"Title: Introduction to (teaching/learning about) digital libraries\\nYear: 2005\\n\\nAbstract: This tutorial provides a thorough and deep introduction to the DL field, building upon a firm theoretical foundation (starting with \\\"5S\\\": Streams, Structures, Spaces, Scenarios, Societies [1]), giving careful definitions and explanations of all the key parts of a \\\"minimal digital library\\\", and expanding from that basis to cover key DL issues, illustrated with a well-chosen set of case studies.\",\n \"Title: The variety of ways in which instructors implement a modular digital library curriculum\\nYear: 2009\\n\\nAbstract: With support from the National Science Foundation, researchers at Virginia Tech and the University of North Carolina developed a curriculum framework and a number of modules for instruction in the area of digital libraries. In 2008, 15 different modules were field tested by 11 instructors at 10 different institutions. As might be expected, instructors adapted these modules to fit the context of their courses, some of which are described here.\",\n \"Title: Evaluating digital libraries with 5SQual\\nYear: 2007\\n\\nAbstract: This work describes 5SQual, a quantitative quality assessment tool for digital libraries based on the 5S framework. 5SQual aims to help administrators of digital libraries during the implementation and maintenance phases of a digital library, providing ways to verify the quality of digital objects, metadata and services. The tool has been designed in a flexible way, which allows it to be applied to many systems, as long as the necessary data is available. To facilitate the input of these data, the tool provides a wizard-like interface that guides the user through its configuration process.\",\n \"Title: SIERRA – a superimposed application for enhanced image description and retrieval\\nYear: 2006\\n\\nAbstract: In this demo proposal, we describe our prototype application, SIERRA, which combines text-based and content-based image retrieval and allows users to link together image content of varying document granularity with related data like annotations. To achieve this, we use the concept of superimposed information (SI), which enables users to (a) deal with information of varying granularity (sub-document to complete document), and (b) select or work with information elements at sub-document level while retaining the original context.\",\n \"Title: Inferring loss-of-heterozygosity from unpaired tumors using high-density oligonucleotide SNP arrays.\\nYear: 2006\\n\\nAbstract: Loss of heterozygosity (LOH) of chromosomal regions bearing tumor suppressors is a key event in the evolution of epithelial and mesenchymal tumors. Identification of these regions usually relies on genotyping tumor and counterpart normal DNA and noting regions where heterozygous alleles in the normal DNA become homozygous in the tumor. However, paired normal samples for tumors and cell lines are often not available. With the advent of oligonucleotide arrays that simultaneously assay thousands of single-nucleotide polymorphism (SNP) markers, genotyping can now be done at high enough resolution to allow identification of LOH events by the absence of heterozygous loci, without comparison to normal controls. Here we describe a hidden Markov model-based method to identify LOH from unpaired tumor samples, taking into account SNP intermarker distances, SNP-specific heterozygosity rates, and the haplotype structure of the human genome. When we applied the method to data genotyped on 100 K arrays, we correctly identified 99% of SNP markers as either retention or loss. We also correctly identified 81% of the regions of LOH, including 98% of regions greater than 3 megabases. By integrating copy number analysis into the method, we were able to distinguish LOH from allelic imbalance. Application of this method to data from a set of prostate samples without paired normals identified known regions of prevalent LOH. We have developed a method for analyzing high-density oligonucleotide SNP array data to accurately identify of regions of LOH and retention in tumors without the need for paired normal samples.\",\n \"Title: Caching Proxies: Limitations and Potentials\\nYear: 1996\\n\\nAbstract: As the number of World-Wide Web users grow, so does the number of connections made to servers. This increases both network load and server load. Caching can reduce both loads by migrating copies of server files closer to the clients that use those files. Caching can either be done at a client or in the network (by a proxy server or gateway). We assess the potential of proxy servers to cache documents retrieved with the HTTP protocol. We monitored traffic corresponding to three types of educational workloads over a one semester period, and used this as input to a cache simulation. Our main findings are (1) that with our workloads a proxy has a 30-50% maximum possible hit rate no matter how it is designed; (2) that when the cache is full and a document is replaced, least recently used (LRU) is a poor policy, but simple variations can dramatically improve hit rate and reduce cache size; (3) that a proxy server really functions as a second level cache, and its hit rate may tend to decline with time after initial loading given a more or less constant set of users; and (4) that certain tuning configuration parameters for a cache may have little benefit.\",\n \"Title: Building digital libraries from simple building blocks\\nYear: 2003\\n\\nAbstract: Metadata harvesting has been established by the Open Archives Initiative as a viable mechanism for connecting a provider of data to a purveyor of services. The Open Digital Library model is an emerging framework which attempts to break up the services into appropriate components based also on the basic philosophy of the OAI model. This framework has been applied to various projects and evaluated for its simplicity, extensibility and reusability to support the hypothesis that digital libraries should be built from simple Web service-like components instead of as monolithic software applications.\",\n \"Title: Using bilingual ETD collections to mine phrase translations\\nYear: 2007\\n\\nAbstract: Phrase translation lists can enhance cross-language information retrieval. However, finding translations for technical phrases is difficult. Bilingual dictionaries have limited coverage for specialized fields, and even more limited coverage of technical phrases. Since phrases can have very specific meanings in technical fields, this limits the quality of translations produced by generic machine translation systems. We hypothesize that digital libraries of electronic theses and dissertations (ETDs) are a good source of technical phrase translations. We have acquired a collection of 3,086 Spanish ETDs about computer science from Scirus, the Universidad Nacional Autónoma de México (Mexico City), and Universidad de las Américas (Puebla). By using English ETDs from NDLTD, we have a comparable corpus of computing-related documents from which to mine phrase translations. We describe our method and its formative evaluation.\",\n \"Title: Practical enhanced Boolean retrieval: Experiences with the smart and sire systems\\nYear: 1988\\n\\nAbstract: During the last decade, studies with the SMART and SIRE systems have pioneered new techniques for improving the effectiveness of Boolean retrieval. Extended Boolean logic, automatic Boolean query construction, and Boolean feedback yield significant improvements according to a variety of experiments with SMART. Ranking of the output of Boolean queries has been shown to be of value with SIRE. Recent efforts have aimed at adapting SMART to allow large scale testing of these advanced retrieval methods. SIRE has been enhanced to include the p-norm scheme for extended Boolean query processing. Implementation and performance details about SMART and SIRE illustrate how commercially available retrieval systems can be improved to use the fruits of these research efforts.\",\n \"Title: A Lightweight Protocol between Digital Libraries and Visualization Systems\\nYear: 2002\\n\\nAbstract: A lightweight protocol, VIDI, is proposed to enhance the interoperability of digital libraries (DLs) and visualization systems (VIS). VIDI is related to the Open Digital Library project, which encourages a component-based approach to the construction of digital libraries, implemented by extending the Open Archives Initiative Protocol for Metadata Harvesting. VIDI adds in the concept of a registry of transformers to convert between common metadata and visualization formats. Design and implementation discussions of VIDI explain its feasibility, flexibility, and generality.\",\n \"Title: Streams, structures, spaces, scenarios, societies (5s): A formal model for digital libraries\\nYear: 2004\\n\\nAbstract: Digital libraries (DLs) are complex information systems and therefore demand formal foundations lest development efforts diverge and interoperability suffers. In this article, we propose the fundamental abstractions of Streams, Structures, Spaces, Scenarios, and Societies (5S), which allow us to define digital libraries rigorously and usefully. Streams are sequences of arbitrary items used to describe both static and dynamic (e.g., video) content. Structures can be viewed as labeled directed graphs, which impose organization. Spaces are sets with operations on those sets that obey certain constraints. Scenarios consist of sequences of events or actions that modify states of a computation in order to accomplish a functional requirement. Societies are sets of entities and activities and the relationships among them. Together these abstractions provide a formal foundation to define, relate, and unify concepts---among others, of digital objects, metadata, collections, and services---required to formalize and elucidate \\\"digital libraries\\\". The applicability, versatility, and unifying power of the 5S model are demonstrated through its use in three distinct applications: building and interpretation of a DL taxonomy, informal and formal analysis of case studies of digital libraries (NDLTD and OAI), and utilization as a formal basis for a DL description language.\",\n \"Title: Using an education oriented digital library to organize and present classes in computing and information\\nYear: 2003\\n\\nAbstract: This demonstration allows conference attendees to gain experience in using the facilities of the NSF National Science Technology Engineering and Mathematics Education Digital Library (NSDL) to prepare and present College or university level classes.\",\n \"Title: Towards a digital library theory: a formal digital library ontology\\nYear: 2008\\n\\nAbstract: Digital libraries (DLs) have eluded definitional consensus and lack agreement on common theories and frameworks. This makes comparison of DLs extremely difficult, promotes ad-hoc development, and impedes interoperability. In this paper we propose a formal ontology for DLs that defines the fundamental concepts, relationships, and axiomatic rules that govern the DL domain, therefore providing a frame of reference for the discussion of essential concepts of DL design and construction. The ontology is an axiomatic, formal treatment of DLs, which distinguishes it from other approaches that informally define a number of architectural variants. The process of construction of the ontology was guided by 5S, a formal framework for digital libraries. To test its expressibility we have used the ontology to create a taxonomy of DL services and to reason about issues of reusability, extensibility, and composability. Some practical applications of the ontology are also described including: the definition of a digital library services taxonomy, the proposal of a modeling language for digital libraries, and the specification of quality metrics to evaluate digital libraries. We also demonstrate how to use the ontology to formally describe DL architectures and to prove some properties about them, thus helping to further validate the ontology.\",\n \"Title: Building quality into a digital library\\nYear: 2000\\n\\nAbstract: The Web Characterization Repository contains a collection of internet log files used by researchers to analyze and improve on the architecture of the Web. This repository improves on prior collections by thoroughly testing the log files for format to assure a degree of data quality. Instituting quality control into the digital library addressed many complex issues including technical support for quality assessment, the definition of a workflow to achieve quality control, the assignment of tasks to different people and the definition and automation of quality assessment for log files. By reaching realistic compromises on these issues it was possible to build quality control as an integral part of the digital library.\",\n \"Title: Virtual DL poster sessions in second life\\nYear: 2009\\n\\nAbstract: In Second Life (SL), a popular general-purpose 3D virtual world, we are supporting the Digital Library community in a variety of ways, including through virtual poster sessions. This brings together the interests of those involved in JCDL 2009, IEEE-TCDL, and NSF-supported work in SL aimed to assist education, training, and dissemination in the digital preservation area.\",\n \"Title: A Bayesian approach to fingerprint minutia localization and quality assessment using adaptable templates\\nYear: 2011\\n\\nAbstract: Fingerprints continue to serve as a reliable trait for human identification. Feature-based matching techniques, such as those used by Automated Fingerprint Identification Systems (AFIS), have demonstrated remarkable success in minutiae-based matching from good quality prints with relatively large extent. As the image quality degrades and acquired fingerprint area decreases, however, the number of reliable minutiae that can be automatically detected decreases, causing match performance to suffer. This paper presents a novel approach to improving the precision of features that can be extracted from fingerprint images. This is accomplished through improved minutia localization and quality assessment routines that are inspired in part by human visual perception. Initial results have shown an improvement in minutia accuracy for 88.2% of fingerprint minutia sets after applying the proposed localization method. An increase in average quality of true minutiae was found for 98.6% of the fingerprint images when using the proposed quality assessment. The results were obtained using a database of 516 fingerprints with ground truth minutiae.\",\n \"Title: Improving simulation management systems through ontology generation and utilization\\nYear: 2011\\n\\nAbstract: Content from simulation systems is useful in defining domain ontologies. We describe a digital library process to generate and leverage domain ontologies to support simulation systems tasks. Workflow ontologies may be used to define compositions of simulation-related services. Simulation model ontologies may be used in customizing collection management systems for tasks such as organization, interface construction, and metadata record generation.\",\n \"Title: Ranking Function Optimization for Effective Web Search by Genetic Programming: An Empirical Study\\nYear: 2004\\n\\nAbstract: Web search engines have become indispensable in our daily life to help us find the information we need. Although search engines are very fast in search response time, their effectiveness in finding useful and relevant documents at the top of the search hit list needs to be improved. In this paper, we report our experience applying Genetic Programming (GP) to the ranking function discovery problem leveraging the structural information of HTML documents. Our empirical experiments using the web track data from recent TREC conferences show that we can discover better ranking functions than existing well-known ranking strategies from IR, such as Okapi, Pt.df. The performance is even comparable to those obtained by Support Vector Machine.\",\n \"Title: Using automatic metadata extraction to build a structured syllabus repository\\nYear: 2007\\n\\nAbstract: Syllabi are important documents created by instructors for students. Gathering syllabi that are freely available, and creating useful services on top of the collection, will yield a digital library of value for the educational community. However, gathering and building a repository of syllabi is complicated by the unstructured nature of syllabus representation and the lack of a unified vocabulary for syllabus construction. In this paper, we propose an intelligent approach to automatically annotate freely-available syllabi from the Web to benefit the educational community through supporting services such as semantic search. We discuss our detailed process for converting unstructured syllabi to structured representations through entity recognition, segmentation, and association. Our evaluation results demonstrate the effiectiveness of our extractor and also suggest improvements. We hope our work will benefit not only users of our services but also people who are interested in building other genre-specific repositories.\",\n \"Title: A content-based image retrieval service for archaeology collections\\nYear: 2006\\n\\nAbstract: Archeological sites have heterogeneous information ranging from different artifacts, image data, geo-spatial information, chronological data, and other relevant metadata. ETANA-DL, an archaeology digital library, provides various services by integrating the heterogeneous data available in different collections. This demonstration presents an initial prototype for searching DL objects based on the image content, using the Content-Based Image Search Component (CBISC) from Virginia Tech/State University of Campinas.\",\n \"Title: Curricula and resources for courses about multimedia (panel session)\\nYear: 2000\\n\\nAbstract: This panel will discuss a recommendation for curricula guidelines for courses about multimedia. Based on conference input, the guidelines will be modified for review prior to future publication by ACM (with other groups). The recommendation will be one of the main results of a June 2000 Dagstuhl workshop led by 4 of the panelists. Dr. Heller, the 5th panelist, also attended that workshop, and is co-PI with the panel moderator on a directly related NSF project, Curriculum Resources in Interactive Multimedia, CRIM, see http://ei.cs.vt.edu/~crim. Each of the panelists has taught courses about multimedia. Each is interested in developing tools/demonstrations/resources to help in those course. Each has a particular area of interest in the multimedia field. Together they constitute a representative group among those who will contribute to and benefit from curricula resources in multimedia.\",\n \"Title: Multimedia traffic analysis using CHITRA95\\nYear: 1995\\n\\nAbstract: We describe how to investigate collections of trace data representing network delivery of multimedia information with CHITRA95, a tool that allows a user to visualize, query, statistically analyze and test, transform, and model collections of trace data. CHITRA95 is applied to characterize World Wide Web (WWW) traffic from three workloads: students in a classroom of network-connected workstations, graduate students browsing the Web, undergraduates browsing educational and other materials, as well as traffic on a courseware repository server. We explore the inter-access time of files on a server (i.e., recency), the hit rate from a proxy server cache, and the distributions of file sizes and media types requested. The traffic study also yields statistics on the effectiveness of caching to improve transfer rates. In contrast to past WWW traffic studies, we analyze client as well as server traffic; we compare three workloads rather than drawing conclusions from one workload; and we analyze tcpdump logs to calculate the performance improvement in throughput that an end user sees due to caching.\",\n \"Title: Architecture of an expert system for composite document analysis, representation, and retrieval\\nYear: 1987\\n\\nAbstract: The CODER (COmposite Document Expert/extended/effective Retrieval) project is a multi-yeare effort to investigate how best to apply artificial intelligence methods to increase the effectiveness of information retrieval systems handling collections of composite documents. To ensure system adaptability and to allow controlled experimentation, CODER has been designed as a distributed expert system. The use of individually tailored specialist experts, coupled with standardized blackboard modules for communication and control and external knowledge bases for maintenance of factual world knowledge, allows for quick prototyping, incremental development, and flexibility under change. The system as a whole is being implemented under UNIX as a set of MU-Prolog and C modules communicating through pipes and TCP/IP sockets.\",\n \"Title: Formal foundations for systematic digital library generation\\nYear: 2013\\n\\nAbstract: Many digital library design, development, and deployment processes are not based on systematic generation activities. The utilization of generation processes enables the precise definition of digital libraries, identification of existing software components, co-generation of multiple digital libraries, and evaluation of a digital library's coverage and completeness. The foundation of a digital library generation process is in the formal framework in which it is described. Two notable formal frameworks have previously been proposed for describing digital libraries and their content, architecture, functionality, and related societies. These two frameworks are merged in this effort to provide the foundation for a generation framework in support of an emerging class of scientific digital libraries.\",\n \"Title: ETANA-DL: managing complex information applications -- an archaeology digital library\\nYear: 2004\\n\\nAbstract: Archaeological research results in the generation of large quantities of heterogeneous information managed by different projects using custom information systems. We will demonstrate a prototype Digital Library (DL) for integrating and managing archaeological data and providing services useful to various user communities ETANA--DL is a model--based, componentized, extensible, archaeological DL that manages complex information sources using the client--server paradigm of the Open Archives Initiative Protocol for Metadata Harvesting (OAI--PMH).\",\n \"Title: Enhancing usability in CITIDEL: multimodal, multilingual, and interactive visualization interfaces\\nYear: 2004\\n\\nAbstract: We describe four usability-enhancing interfaces to CITIDEL aimed at improving the user experience and supporting personalized information access by targeted communities. These comprise: a multimodal interaction facility with capability for out-of-turn input, interactive visualizations for exploratory analysis, a translation center exposing multilingual interfaces, as well as traditional usability enhancements. Pilot studies demonstrate the resulting improvements in quality, as measured across a number of metrics.\",\n \"Title: The Web-DL environment for building digital libraries from the Web\\nYear: 2003\\n\\nAbstract: The Web contains a huge volume of unstructured data, which is difficult to manage. In digital libraries, on the other hand, information is explicitly organized, described, and managed. Community-oriented services are built to attend specific information needs and tasks. In this paper, we describe an environment, Web-DL, that allows the construction of digital libraries from the Web. The Web-DL environment will allow us to collect data from the Web, standardize it, and publish it through a digital library system. It provides support to services and organizational structure normally available in digital libraries, but benefiting from the breadth of the Web contents. We experimented with applying the Web-DL environment to the Networked Digital Library of Theses and Dissertations (NDLTD), thus demonstrating that the rapid construction of DLs from the Web is possible. Also, Web-DL provides an alternative as a largescale solution for interoperability between independent digital libraries.\",\n \"Title: Exploring digital libraries: integrating browsing, searching, and visualization\\nYear: 2006\\n\\nAbstract: Exploring services for digital libraries (DLs) include two major paradigms, browsing and searching, as well as other services such as clustering and visualization. In this paper, we formalize and generalize DL exploring services within a DL theory. We develop theorems to indicate that browsing and searching can be converted or mapped to each other under certain conditions. The theorems guide the design and implementation of exploring services for an integrated archaeological DL, ETANA-DL. Its integrated browsing and searching can support users in moving seamlessly between these operations, minimizing context switching, and keeping users focused. It also integrates browsing and searching into a single visual interface for DL exploration. A user study to evaluate ETANA-DL's exploring services helped validate our hypotheses.\",\n \"Title: World-Wide Web and computer science reports\\nYear: 1995\\n\\nAbstract: With the advent of the World-Wide Web, computing professionals have eagerly pursued the idea of moving from a paper-based technical report service to one that employs networked information systems. Many departments keep some version of their reports on an FTP server to help with this process. To facilitate access to CS reports a number of sites have set up lists of these archives (see sidebar).\",\n \"Title: An Extensible Digital Library Service to Support Network Science.\\nYear: 2013\\n\\nAbstract: Network science research aims to understand the underlying properties of complex networks. Large-scale modeling and simulation is the core of network science research. Existing systems take a long time to run large network science experiments with high performance computing resources. Scientific data management systems currently lack the performance efficiency needed to support this type of computation and data-intensive research. Memoization provides the ability to index, archive, and reuse frequently requested and expensive to re-compute datasets. In this paper, a domain independent memoization service to increase the computational execution process performance within cyberinfrastructure-based systems is described. The service is formulated as an extensible memoization framework for the computational and simulation network science domains that is built on top of well-defined metadata objects. We present extensible concepts, discuss the proposed algorithm and framework architecture, and examine the flexible nature of the framework. The framework was utilized as a part of the CINET cyberinfrastructure-based digital library (DL). Our experimental results indicate an increase in the efficiency of the system and recommendation of the service's inclusion in scientific DLs.\",\n \"Title: Visual Semantic Modeling of Digital Libraries.\\nYear: 2003\\n\\nAbstract: The current interest from non-experts who wish to build digital libraries (DLs) is strong worldwide. However, since DLs are complex systems, it usually takes considerable time and effort to create and tailor a DL to satisfy specific needs and requirements of target communities/societies. What is needed is a simplified modeling process and rapid generation of DLs. To enable this, DLs can be modeled with descriptive domain-specific languages. A visual tool would be helpful to non-experts so they may model a DL without knowing the theoretical foundations and the syntactic details of the descriptive language. In this paper, we present a domain-specific visual DL modeling tool, 5SGraph. It employs a metamodel that describes DLs using the 5S theory. The output from 5SGraph is a DL model that is an instance of the metamodel, expressed in the 5S description language. Furthermore, 5SGraph maintains semantic constraints specified by the 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph enables component reuse to reduce the time and effort of designers. 5SGraph also is designed to accommodate and integrate several other complementary tools reflecting the interdisciplinary nature of DLs. Thus, tools based on concept maps to fulfill those roles are introduced. The 5SGraph tool has been tested with real users and several modeling tasks in a usability experiment, and its usefulness and learnability have been demonstrated.\",\n \"Title: Online evaluation in WWW-based courseware\\nYear: 1997\\n\\nAbstract: The QUIZIT system has been developed to support adaptive as well as standard testing, along with automatic grading and record keeping, using the WWW as a delivery vehicle. In connection with our Interactive Learning with a Digital Library in Computer Science project, we have applied QUIZIT to help with a master's level course as well as a large freshman level service course. Preliminary testing has led to various improvements, and it appears that QUIZIT will be well received by both instructors and students. It should port easily to a variety of environments and so could be widely used at other institutions as well.\",\n \"Title: A genetic programming framework for content-based image retrieval\\nYear: 2009\\n\\nAbstract: The effectiveness of content-based image retrieval (CBIR) systems can be improved by combining image features or by weighting image similarities, as computed from multiple feature vectors. However, feature combination do not make sense always and the combined similarity function can be more complex than weight-based functions to better satisfy the users' expectations. We address this problem by presenting a Genetic Programming framework to the design of combined similarity functions. Our method allows nonlinear combination of image similarities and is validated through several experiments, where the images are retrieved based on the shape of their objects. Experimental results demonstrate that the GP framework is suitable for the design of effective combinations functions.\",\n \"Title: An expert system for selecting liquid chromatographic separation methods\\nYear: 1987\\n\\nAbstract: The Expert Separation Program (ESP) is an expert system designed to aid the inexperienced analytical chemist in choosing a separation method for High Performance Liquid Chromatography (HPLC). Properties of compounds—molecular weight, solubility, polarity, ionic nature, acid/base character, pH dependence, presence of isomers, and presence of functional groups—drive reasoning from first principles. Prolog supports a production rule approach to selecting and explaining a separation system characterized by: column, solvent system, buffer and detector.\",\n \"Title: A study of automation from seed URL generation to focused web archive development: the CTRnet context\\nYear: 2012\\n\\nAbstract: In the event of emergencies and disasters, massive amounts of web resources are generated and shared. Due to the rapidly changing nature of those resources, it is important to start archiving them as soon as a disaster occurs. This led us to develop a prototype system for constructing archives with minimum human intervention using the seed URLs extracted from tweet collections. We present the details of our prototype system. We applied it to five tweet collections that had been developed in advance, for evaluation. We also identify five categories of non- relevant files and conclude with a discussion of findings from the evaluation.\",\n \"Title: Automatically Generating Interfaces for Personalized Interaction with Digital Libraries\\nYear: 2004\\n\\nAbstract: We present an approach to automatically generate interfaces supporting\\npersonalized interaction with digital libraries; these interfaces augment the\\nuser-DL dialog by empowering the user to (optionally) supply out-of-turn\\ninformation during an interaction, flatten or restructure the dialog, and\\nenquire about dialog options. Interfaces generated using this approach for\\nCITIDEL are described.\",\n \"Title: Digital libraries for education: case studies\\nYear: 2004\\n\\nAbstract: Digital libraries may have extraordinary impact on education, especially in Asia where vast communities could benefit from improved teaching and learning. We highlight opportunities and challenges, drawing upon three case studies. Thus, we explore how CITIDEL, a discipline-specific Digital Library for Education (DLE), oriented toward computing, has evolved, and constitutes a part of the US National Science Digital Library (NSDL), which includes over 160 projects. By way of contrast, we describe the grass-roots and low-cost global movement toward electronic theses and dissertations led by NDLTD. Summarizing lessons learned from these case studies, we suggest ways forward so that DLEs in Asia may engage the diverse stakeholders whose serious involvement can ensure sustainable success.\",\n \"Title: Exploring the computing literature with visualization and stepping stones & pathways\\nYear: 2006\\n\\nAbstract: An alternative interpretation of queries involves splitting a query into parts that cover different but connected aspects of the information needed.\",\n \"Title: Web-DL: an experience in building digital libraries from the web\\nYear: 2002\\n\\nAbstract: The Web contains a huge volume of information, almost all unstructured and, therefore, difficult to manage. In Digital Libraries, however, information is explicitly organized, described, and managed. In this paper, we propose an architecture that allows the construction of digital libraries from the Web, using standard protocols and archival technologies, and incorporating powerful digital library and data extraction tools, thus benefiting from the breadth of the Web contents, but supporting services and organization available in digital libraries. The proposed architecture was applied to the Networked Digital Library of Theses and Dissertations, providing an important first step toward rapid construction of large DLs from the Web, as well as a large-scale solution for interoperability between independent digital libraries.\",\n \"Title: The effects of fitness functions on genetic programming-based ranking discovery forWeb search\\nYear: 2004\\n\\nAbstract: Genetic-based evolutionary learning algorithms, such as genetic algorithms (GAs) and genetic programming (GP), have been applied to information retrieval (IR) since the 1980s. Recently, GP has been applied to a new IR task-discovery of ranking functions for Web search-and has achieved very promising results. However, in our prior research, only one fitness function has been used for GP-based learning. It is unclear how other fitness functions may affect ranking function discovery for Web search, especially since it is well known that choosing a proper fitness function is very important for the effectiveness and efficiency of evolutionary algorithms. In this article, we report our experience in contrasting different fitness function designs on GP-based learning using a very large Web corpus. Our results indicate that the design of fitness functions is instrumental in performance improvement. We also give recommendations on the design of fitness functions for genetic-based information retrieval experiments.\",\n \"Title: Lexical relations: enhancing effectiveness of information retrieval systems\\nYear: 1980\\n\\nAbstract: One of the essential features of the \\\"Meaning Text\\\" model (MTM) developed by I. A. Mel'chuk et. al. is the special lexicon or ECD ('explanatory and combinatory' dictionary). This component can be thought of as a collection independent thesaurus, and can be applied to improve the effectiveness of an information retrieval system.After outlining the MTM and related work, this paper briefly describes the SMART type of information retrieval system. Applicability of the above-mentioned lexicon to such a system is discussed. In particular, the list of lexical relations included in the ECD is expanded and organized to be more effective for retrieval, partially along the lines suggested by Evens and Smith.Finally, an experimental analysis of the utility of lexical relations in an information retrieval system is discussed. It is shown that lexical relations generally enhance system performance. When all lexical relations are considered in the comparison, the resulting performance is shown, by statistical methods, to make a significant improvement (up to 16.5% at a single recall level); when all lexical relations except for antonyms are considered, the improvement is even greater (up to 20.2% at a single recall level).\",\n \"Title: SimFusion: measuring similarity using unified relationship matrix\\nYear: 2005\\n\\nAbstract: In this paper we use a Unified Relationship Matrix (URM) to represent a set of heterogeneous data objects (e.g., web pages, queries) and their interrelationships (e.g., hyperlinks, user click-through sequences). We claim that iterative computations over the URM can help overcome the data sparseness problem and detect latent relationships among heterogeneous data objects, thus, can improve the quality of information applications that require com- bination of information from heterogeneous sources. To support our claim, we present a unified similarity-calculating algorithm, SimFusion. By iteratively computing over the URM, SimFusion can effectively integrate relationships from heterogeneous sources when measuring the similarity of two data objects. Experiments based on a web search engine query log and a web page collection demonstrate that SimFusion can improve similarity measurement of web objects over both traditional content based algorithms and the cutting edge SimRank algorithm.\",\n \"Title: Digital libraries settling the score: 10 years hence and 10 before\\nYear: 2004\\n\\nAbstract: Six panelists and a moderator leverage knowledge of the first ten years of the digital libraries field, to suggest key future directions.\",\n \"Title: Experiment and analysis services in a fingerprint digital library for collaborative research\\nYear: 2011\\n\\nAbstract: Fingerprint management systems support millions of images and complicated but imperfect image identification algorithms. The forensic community requires a set of digital library services to support large image collections, execute identification algorithms, and analyze experiments that test identification algorithms in development. We present a model and prototype system capable of testing and analyzing fingerprinting algorithms in terms of identification performance based on matches of a known image to partial images, distortions of the images, and sub-regions of the images. These services are provided based on our framework for composing a set of services and a fingerprint image collection. The prototype will be useful in collaborations connecting several algorithm development efforts, and in composing an experimentation workflow. We also describe extensions of these services into other domains.\",\n \"Title: A scalable data management tool to support epidemiological modeling of large urban regions\\nYear: 2007\\n\\nAbstract: We describe the design and prototype implementation of a data management tool supporting simulation based models for studying the spread of infectious diseases in large urban regions. The need for such tools arises due to diverse and competing disease models, social networks, and experimental designs that are being investigated. A realistic case study produces large amounts of data. Organizing such datasets is necessary for effectively supporting analysts and policy-makers interested in various cases. We report our ongoing efforts to develop EpiDM--an integrated information management tool for interrelated digital resources, where the central piece is EpiDL(a digital library for efficient access to these datasets). The work is unique in terms of the specific application domain, which we are not aware of any such efforts and tools that can be generalized for simulation-based modeling of other sociotechnical systems. EpiDL follows the 5S framework developed in the DL community.\",\n \"Title: How to Make Intelligent Digital Libraries\\nYear: 1994\\n\\nAbstract: Building digital libraries is one of the most important Grand Challenge problems faced by information professionals. This paper surveys the relevant literature and includes recommendations for research, based on our experience with a digital library for computer science and its use in improving undergraduate education. Of particular interest is the application of intelligent system methods to help provide an effective solution. Mediators or agents are needed throughout the system. It is also important to improve the interface, help with searching, and in general allow the digital library to carry out many of the functions of an expert human intermediary.\",\n \"Title: Wide area technical report service—technical reports online\\nYear: 1994\\n\\nAbstract: Wide Area Technical Report Service (WATERS) is a distributed database of computer science technical reports. Contributors are departments of computer science that make their reports, stored locally at their sites, available through World-Wide Web and a WAIS search engine. By using WATERS, anyone with access to the Internet can, using a client such as Mosaic browse, search, obtain abstract and bibliographic information, and retrieve technical reports online. The latter assumes that the user's WWW client is set up to launch viewers such as ghostview for Postscript files, xdvi for dvi files, and xtiff for TIFF page images.\",\n \"Title: A relevance feedback approach for the author name disambiguation problem\\nYear: 2013\\n\\nAbstract: This paper presents a new name disambiguation method that exploits user feedback on ambiguous references across iterations. An unsupervised step is used to define pure training samples, and a hybrid supervised step is employed to learn a classification model for assigning references to authors. Our classification scheme combines the Optimum-Path Forest (OPF) classifier with complex reference similarity functions generated by a Genetic Programming framework. Experiments demonstrate that the proposed method yields better results than state-of-the-art disambiguation methods on two traditional datasets.\",\n \"Title: Superimposed Information Architecture for Digital Libraries\\nYear: 2008\\n\\nAbstract: A variety of software tools commonly used in research and industry allow a user to select (usually contiguous) segments of content to be annotated, referenced, or otherwise distinguished from a containing document. However, digital libraries (DLs) often curate only full documents, not these selected sub-documents. Thus, sub-documents in a DL may not have the full complement of metadata, and they may not be visible using DL browse and search facilities. We are interested in explicit representation of sub-documents in a DL environment. In this paper, we show how sub-documents may be represented and curated. We focus on the explicit representation of what we call a mark- an encapsulated address of a sub-document along with associated context. Our contributions are: a software architecture for representing marks as first-class objects together with regular documents in a DL; and an implementation of our architecture using existing software packages with modest enhancements. This approach provides new capabilities for the DL with minimal modification to tools and interfaces familiar to the DL user.\",\n \"Title: Implementing SMART for minicomputers via relational processing With abstract data types\\nYear: 1981\\n\\nAbstract: Designed during the 1960's as a research tool for the field of information retrieval, the SMART system has been operating on an IBM 370 since 1974. SMART is now being enhanced, redesigned, and programmed under the UNIX operating system [28] on a DEC VAX 11/780. The techniques used should allow real-time operation on smaller minicomputers in the PDP 11 family. The implementation provides for a combination of database and information retrieval operations which make it applicable to office automation, personal information system management, and research studies. The SMART vector space model, which treats information requests and stored information records as vectors in an n-space (of terms), is integrated into the relational database model using the concepts of abstract data types (ADTs). Domains of relations are allowed to be any ADT; an extended relational algebra is described with operators that manipulate many complex data structures. After illustrating the application of these concepts to typical SMART tasks, a prototype implementation is outlined. Also included is a discussion of techniques to be employed in a more efficient version.\",\n \"Title: A hybrid two-stage approach for discipline-independent canonical representation extraction from references\\nYear: 2012\\n\\nAbstract: In education and research, references play a key role. However, extracting and parsing references are difficult problems. One concern is that there are many styles of references; hence, given a surface form, identifying what style was employed is problematic, especially in heterogeneous collections of theses and dissertations, which cover many fields and disciplines, and where different styles may be used even in the same publication. We address these problems by drawing upon suitable knowledge found in the WWW. In particular, we research a two-stage classifier approach, involving multi-class classification with respect to reference styles, and partially solve the problem of parsing surface representations of references. We describe empirical evidence for the effectiveness of our approach and plans for improvement of our methods.\",\n \"Title: Personal digital library: pim through a 5s perspective\\nYear: 2007\\n\\nAbstract: Information overload and fragmentation problems result from the huge volume of data available in digital formats. This has led to increasing interest in personal information management research. However, current efforts have not fully clarified the thinking in this area due to the lack of theoretical foundations. In this paper, we present a formal framework for personal information management through a personal digital library perspective based upon the 5S approach. This framework includes a formal definition of the components and functionalities for a minimal personal digital library. We also present the primary testing results of our initial implementation of receptor module and behavioral information relevance. Challenges expected in planned future efforts are discussed too, with suggestions for possible solutions. We believe this is one of the first efforts to provide a theoretical foundation for personal information management. Our results and planned work show promise for further doctoral research.\",\n \"Title: ETANA-ADD: an interactive tool for integrating archaeological DL collections\\nYear: 2006\\n\\nAbstract: ETANA-DL is an archaeology digital library built based on the principles of Open Digital Libraries. A key challenge addressed in ETANA-DL is integration of new archaeological sites. To enable archaeologists to build OAI data providers for easy integration, we developed an interactive software tool for database-to-XML generation, schema mapping, and global archive generation. This tool greatly enhances our ability to build new Open Archives. We tested the tool with data from the Umm el-Jimal site.\",\n \"Title: 5SGraph demo: a graphical modeling tool for digital libraries\\nYear: 2003\\n\\nAbstract: The current demand from non-experts who wish to build digital libraries is strong worldwide. However, since DLs are complex systems, it usually takes a huge amount of effort and time to create and tailor a digital library to satisfy specific needs and requirements of target communities/societies. What is desired is a simplified modeling process and rapid generation of digital libraries. To enable this, digital libraries should be modeled with descriptive domain-specific languages [1]. In a domain-specific modeling language, the models are made up of elements representing concepts, rules, and terminology that are part of the domain world, as opposed to the code world or generic modeling languages (e.g., UML [2]). A visual modeling tool would be helpful to non-experts so they may model a digital library without knowing the theoretical foundations and the syntactical details of the descriptive language.In this demonstration, we present a domain-specific visual modeling tool, 5SGraph, aimed at modeling digital libraries. 5SGraph is based on a metamodel that describes DLs using the 5S theory [3]. The output from 5SGraph is a digital library model that is an instance of the metamodel, expressed in the 5S description language (5SL) [4].5SGraph presents the metamodel in a structured toolbox, and provides a top-down visual building environment for designers (see Figure 1). The visual proximity of the metamodel and instance model facilitates requirements gathering and simplifies the modeling process. Furthermore, 5SGraph maintains semantic constraints specified by the 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph enables component reuse to reduce the time and efforts of designers. 5SGraph also is designed to be flexible and extensible, able to accommodate and integrate several other complementary tools (e.g., to model scenarios or complex digital objects), reflecting the interdisciplinary nature of digital libraries. The tool has been tested with real users and several modeling tasks in a usability experiment [5] and its usefulness and learnability have been demonstrated.\",\n \"Title: The XML log standard for digital libraries: analysis, evolution, and deployment\\nYear: 2003\\n\\nAbstract: We describe current efforts and developments building on our proposal for an XML log standard format for digital library (DL) logging analysis and companion tools. Focus is given to the evolution of formats and tools, based on analysis of deployment in several DL systems and testbeds. Recent development of analysis tools also is discussed.\",\n \"Title: Using a frame-based language for information retrieval.\\nYear: 1989\\n\\nAbstract: With the advent of the information society, many researchers are turning to artificial intelligence techniques to provide effective retrieval over large bodies of textual information. In the CODER system, the mission of which is to provide an environment for experiments in applying AI to information retrieval, a factual representation language (FRL) serves as a tool for knowledge engineering and experimentation. the FRL is a hybrid AI language supporting strong typing for attribute values, a frame system, and Prolog-like relational structures. Inheritance is enforced throughout, and the semantics of type subsumption and object matching are formally defined. A collection of type and object managers called the knowledge administration complex implements this common language for storing knowledge and communicating it within the system. Storage of large numbers of complete knowledge objects (statements in the language) is supported by a system of external knowledge bases. Of the three types of knowledge structures in the language, the frame facility has proven most useful in the retrieval domain. This article discusses the frame construct itself, the implementation of the relevant portions of the knowledge administration complex and external knowledge bases, and the use of frames in retrieval research. It closes with a discussion of the utility of the FRL. (This material is based in part upon work supported by the National Science Foundation under Grant Nos. IST-8418877 and IRI-8703580; by the Virginia Center for Innovative Technology under Grant No. INF-85-016; and by grants from Nimbus Records and AT&T. A more detailed version of this article is available from the VPI&SU Department of Computer Science as Technical Report TR-88-25. © 1989 Wiley Periodicals, Inc.)\",\n \"Title: Practical minimal perfect hash functions for large databases\\nYear: 1992\\n\\nAbstract: We describe the first practical algorithms for finding minimal perfect hash functions that have been used to access very large databases (i.e., having over 1 million keys). This method extends earlier work wherein an 0(n-cubed) algorithm was devised, building upon prior work by Sager that described an 0(n-to the fourth) algorithm. Our first linear expected time algorithm makes use of three key insights: applying randomness whereever possible, ordering our search for hash functions based on the degree of the vertices in a graph that represents word dependencies, and viewing hash value assignment in terms of adding circular patterns of related words to a partially filled disk. Our second algorithm builds functions that are slightly more complex, but does not build a word dependency graph and so approaches the theoretical lower bound on function specification size. While ultimately applicable to a wide variety of data and file access needs, these algorithms have already proven useful in aiding our work in improving the performance of CD-ROM systems and our construction of a Large External Network Database (LEND) for semantic networks and hypertext/hypermedia collections. Virginia Disc One includes a demonstration of a minimal perfect hash function running on a PC to access a 130,198 word list on that CD-ROM. Several other microcomputer, minicomputer, and parallel processor versions and applications of our algorithm have also been developed. Tests including those wiht a French word list of 420,878 entries and a library catalog key set with over 3.8 million keys have shown that our methods work with very large databases.\",\n \"Title: Research and development of information retrieval models and their application\\nYear: 1989\\n\\nAbstract: In recent years there has been a rapid growth in interest about information retrieval as new storage, processing, and communication technologies emerge that will aid individuals to directly search for and utilize helpful data, information, and knowledge. Since conventional retrieval systems have numerous limitations it is important to consider work by leading researchers in developing new models and in extending and applying already proposed experimental models. Much of that work has been first presented at 1 of the 11 conferences sponsored by the Association for Computing Machinery (ACM) Special Interest Group on Information Retrieval (SIGIR). This article summarizes and introduces a series of 11 articles that had their origins in papers presented at the Tenth Annual International ACM SIGIR Conference on Research & Development in Information Retrieval, June 3–5, 1987, New Orleans, Louisiana. Seven of those articles appear in this Special Issue; the remaining four and perhaps others derived from the 1987 conference papers will appear in subsequent issues of this journal. The articles and ideas introduced relate to: modeling data, information, and knowledge; Boolean logic; probability theory; artificial intelligence; organizing and encoding information and data; and characteristics of users of retrieval systems.\",\n \"Title: Social navigation for educational digital libraries\\nYear: 2010\\n\\nAbstract: An educational digital library may store a wealth of diverse educational resources targeting different audiences from young schoolchildren to graduate students to school and college teachers. With the growth of the volume and the diversity of the library, it becomes increasingly difficult for the users to find resources, which are relevant to their age, educational needs, and personal interests. Social navigation techniques could provide valuable help in this context guiding users to the most useful information. Social navigation works by processing traces of past user behavior and using the assembled “collective wisdom” to guide future users. The paper reports our work on the design of social navigation infrastructure for Ensemble, a major educational digital library. We present the organization of both sides of the social navigation process: how social wisdom is collected and how it can be used to guide portal users to valuable resources. We also report the results of our most recent evaluation of the social navigation infrastructure.\",\n \"Title: The networked digital library of theses and dissertations: Changes in the university community\\nYear: 2002\\n\\nAbstract: DIGITAL LIBRARIES are one of the most effective vehicles for change in higher education. They facilitate collaboration involving\\n universities in an international cooperative venture, unlocking scholarly resources, and carrying out functions previously\\n limited to publishers. They allow faculty and students to improve learning by drawing on rapidly growing collections of valuable\\n content—heretofore largely hidden behind the doors of the library—that include an increasing proportion of multimedia elements\\n or interactive software.\\n \\n The Networked Digital Library of Theses and Dissertations (NDLTD), launched in 1996 and building upon work started in 1987,\\n is a federated effort involving well over 120 universities scattered around the globe. Rapidly growing as a result of local,\\n state, regional, national, and international efforts, it aims to enhance the skills of all graduate students preparing theses\\n or dissertations, so they are empowered to create an electronic thesis or dissertation (ETD) and to effectively use digital\\n libraries. As universities move to require submission of ETDs, they build the local infrastructure to support their own students\\n in this regard and to dramatically enhance access to this important genre of scholarly publication. NDLTD supports these changes\\n and helps ensure that the move to ETDs remains a sustainable initiative that will continue to enhance university libraries\\n and publishing.\",\n \"Title: Using concept maps in digital libraries as a cross-language resource discovery tool\\nYear: 2005\\n\\nAbstract: The concept map, first suggested by Joseph Novak, has been extensively studied as a way for learners to increase understanding. We are automatically generating and translating concept maps from electronic theses and dissertations, for both English and Spanish, as a DL aid to discovery and summarization.\",\n \"Title: Automatic evaluation of digital libraries with 5SQual\\nYear: 2009\\n\\nAbstract: Digital libraries (DLs) are complex information systems which can present changes in their structure, content, and services. These complexities and dynamics make system maintenance a non-trivial task, since it requires periodical evaluation of the different DL components. Generally, these evaluations are customized per system and are performed only when problems occur and administrator intervention is required. This work aims to change the situation. We present 5SQual, a tool which provides ways to perform automatic and configurable evaluations of some of the most important DL components, among them, digital objects, metadata, and services. The tool implements diverse numeric indicators that are associated with eight quality dimensions described in the 5S quality model. Its generic architecture was developed to be applicable to various DLs and scenarios. In sum, the main contributions of this work include: (i) the design and implementation of 5SQual, a tool that validates a theoretical DL quality model; (ii) the demonstration of the applicability of the tool in several usage scenarios; and (iii) the evaluation (with usability specialists) of its graphical interface specially designed to guide the configuration of 5SQual evaluations. We also present the results of interviews conducted with administrators of real DLs regarding their expectations and opinions about 5SQual.\",\n \"Title: The effectiveness of automatically structured queries in digital libraries\\nYear: 2004\\n\\nAbstract: Structured or fielded metadata is the basis for many digital library services, including searching and browsing. Yet, little is known about the impact of using structure on the effectiveness of such services. In this paper, we investigate a key research question: do structured queries improve effectiveness in DL searching? To answer this question, we empirically compared the use of unstructured queries to the use of structured queries. We then tested the capability of a simple Bayesian network system, built on top of a DL retrieval engine, to infer the best structured queries from the keywords entered by the user. Experiments performed with 20 subjects working with a DL containing a large collection of computer science literature clearly indicate that structured queries, either manually constructed or automatically generated, perform better than their unstructured counterparts, in the majority of cases. Also, automatic structuring of queries appears to be an effectiveand viable alternative to manual structuring that may significantly reduce the burden on users.\",\n \"Title: A new framework to combine descriptors for content-based image retrieval\\nYear: 2005\\n\\nAbstract: In this paper, we propose a novel framework using Genetic Programming to combine image database descriptors for content-based image retrieval (CBIR). Our framework is validated through several experiments involving two image databases and specific domains, where the images are retrieved based on the shape of their objects.\",\n \"Title: Scenario-Based Generation of Digital Library Services.\\nYear: 2003\\n\\nAbstract: We describe the development, implementation, and deployment of a new generic digital library generator yielding implementations of digital library services from models of DL \\\"societies\\\" and \\\"scenarios\\\". The distinct aspects of our solution are: 1) approach based on a formal, theoretical framework; 2) use of state-of-the-art database and software engineering techniques such as domain-specific declarative languages, scenario synthesis, componentized and model driven architectures; 3) analysis centered on scenario-based design and DL societal relationships; 4) automatic transformations and mappings from scenarios to workflow designs and from these to Java implementations, 5) special attention paid to issues of simplicity of implementation, modularity, reusability, and extensibility. We demonstrate the feasibility of the approach through a number of examples.\",\n \"Title: EtanaCMV: a visual browsing interface for ETANA-DL based on coordinated multiple views\\nYear: 2006\\n\\nAbstract: Visual interfaces for digital libraries (DLs) provide support for insightful browsing, presentation of search results in a browsing platform, and analysis of records in the DL. We propose the demonstration of a visual interface to ETANA–DL, a growing union archaeological DL. Our interface EtanaCMV is based on a uniform multiple view design and facilitates browsing of DL records that are multidimensional, hierarchical, and categorical in nature. We use distinct panels to allow flexible browsing across multiple dimensions. Bars in each panel denote the various categories in each dimension. EtanaCMV will give the users a quick overview of the collections in the DL during browsing in addition to showing relationships in the harvested collections. Coordination between multiple views is used to present more insights into the data.\",\n \"Title: US-Korea Collaboration on Digital Libraries: An Overview and Generalization for Pacific Rim Collaboration\\nYear: 2002\\n\\nAbstract: We report on recommendations to remove barriers to worldwide development of digital libraries, drawing upon an Aug. 2000 workshop involving researchers from the US and Korea who met at the San Diego Supercomputer Center. We developed a summary table identifying application domains (e.g., education), institutions engaged in those applications, example activities, technical challenges, and possible benefits. Since education has high priority in Korea, an important opportunity that should be explored is involvement of Koreans in the initiative led by the US NSF to develop the National STEM (Science, Technology, Engineering, and Mathematics) education Digital Library, NSDL.\",\n \"Title: Digital library 2.0 for educational resources\\nYear: 2011\\n\\nAbstract: We report on focus group feedback regarding the services provided by existing education-related Digital Libraries (DL). Participants provided insight into how they seek educational resources online, and what they perceive to be the shortcomings of existing educational DLs. Along with useful content, social interactions were viewed as important supplements for educational DLs. Such interactions lead to both an online community and new forms of content such as reviews and ratings. Based on our analysis of the focus group feedback, we propose DL 2.0, the next generation of digital library, which integrates social knowledge with DL content.\",\n \"Title: Networked Digital Library of Theses and Dissertations: Bridging the Gaps for Global Access - Part 1: Mission and Progress\\nYear: 2001\\n\\nAbstract: The Networked Digital Library of Theses and Dissertations (NDLTD) is a collaborative effort of universities around the world to promote creating, archiving, distributing and accessing Electronic Theses and Dissertations (ETDs). Since its inception in 1996, over a hundred universities have joined the initiative, underscoring the importance institutions place on training their graduates in the emerging forms of digital publishing and information access. The outreach and training mission of NDLTD is an ongoing project so in this article we report on the current status of membership and support activities. Recent research has focused on creating a union database that will provide a means to search and retrieve ETDs from the combined collections of NDLTD member institutions. The Virtua system developed by VTLS will serve as the heart of this union database. In order to bridge the gap between the existing distributed institutional archives and a unified collection of ETDs, we have developed a metadata standard especially suited to ETDs - this is then used by partner sites to export their freely-available metadata using the Metadata Harvesting Protocol of the Open Archives Initiative. We also link name authority information into the metadata records to support unique identification of authors and others associated with the works. Additional research efforts include advanced search mechanisms, semantic interoperability, the design and development of multi- and cross-lingual search systems, and software modules that support the development of higher-level services to aid researchers in seeking relevant ETDs.\",\n \"Title: Moving digital libraries into the student learning space: The GetSmart experience\\nYear: 2006\\n\\nAbstract: The GetSmart system was built to support theoretically sound learning processes in a digital library environment by integrating course management, digital library, and concept mapping components to support a constructivist, six-step, information search process. In the fall of 2002 more than 100 students created 1400 concept maps as part of selected computing classes offered at the University of Arizona and Virginia Tech. Those students conducted searches, obtained course information, created concept maps, collaborated in acquiring knowledge, and presented their knowledge representations. This article connects the design elements of the GetSmart system to targeted concept-map-based learning processes, describes our system and research testbed, and analyzes our system usage logs. Results suggest that students did in fact use the tools in an integrated fashion, combining knowledge representation and search activities. After concept mapping was included in the curriculum, we observed improvement in students' online quiz scores. Further, we observed that students in groups collaboratively constructed concept maps with multiple group members viewing and updating map details.\",\n \"Title: From concepts to implementation and visualization: tools from a team-based approach to ir\\nYear: 2008\\n\\nAbstract: Researchers have been studying and developing teaching materials for information retrieval (IR), such as [3]. Toolkits also have been built that provide hands-on experience to students. For example, IR-Toolbox [4] is an effort to close the gap between the students' understanding of IR concepts and real-life indexing and search systems. Such tools might be good for helping students in non-technical areas such as in the Library and Information Science field to develop their conceptual model of search engines. However, they do not cover emerging topics and skills, such as content-based image retrieval (CBIR) and fusion search. Although there is open source software (such as those in http://www.searchtools.com/tools/tools-opensource.html) that can be used to teach basic and advanced IR topics, they require a student to have high-level technical knowledge and to spend a long time to gain a practical understanding of these topics. We present a new and rapid approach to teach basic and advanced IR topics, such as text retrieval, web-based IR, CBIR, and fusion search, to Computer Science (CS) graduate students. We designed projects that would help students grasp the abovementioned IR topics. Students, working in teams, were given a practical application to start with -- the Superimposed Application for Image Description and Retrieval [5]. SAIDR (earlier, SIERRA) allows users to associate parts of images with multimedia information such as text annotations. Also, users may retrieve information in one of two 2 ways: (1) Perform text-based retrieval on annotations; (2) Perform CBIR on images and parts of images that look like a query image (or part of a query image). Each team was asked to build an enhancement for this application, involving text retrieval and/or CBIR, in three weeks time. The sub-projects are described in Table 1. The outcome of this activity was that students learned about IR concepts while being able to relate their applicability to a real world problem (Figure 1). Details of these projects may be found at http://collab.dlib.vt.edu/runwiki/wiki.pl?TabletPcImageRetrievalSuperimposedInformation. We will demonstrate the tools developed along with the IR concepts they illustrate (Table 1). We believe these tools may aid others to learn about basic and advanced topics in IR.\",\n \"Title: Design And Analysis Of A Set-Top Box For Video Streaming Services\\nYear: 2002\\n\\nAbstract: We. design arid validate methods for implementing a software-based digital set-top box for handling concurrent live video streams. Unlike conventional video servers that, handle only read requests to retrieve prerecorded video titles, a set-top box must handle write requests to store concurrent live video streams for later viewing. Moreover, it must react to user interactive functions such as pausing a live video stream while recording the video stream in the background or switching to another live video stream in real-time. The functional requirements of set-top boxes thus are vastly different from that of conventional video servers. We model and identify minimum resource requirements for the set-top box to function respectably based on our design and analyze design trade-offs for achieving certain performance goals.\",\n \"Title: Entertainment history museums in virtual worlds: video game and music preservation in second life\\nYear: 2010\\n\\nAbstract: This research explores and demonstrates the use of Second Life (the popular 3D virtual world) for the purpose of digitally preserving various aspects of video game and music history. Physical game interfaces like joysticks, advertisements used for games, and famous game characters and cultural icons over the history are displayed and preserved in multiple video game exhibits for different eras. Selected game characters are digitally recreated in 3D format as Second Life avatar appearances. Historical changes of musical instruments, musicians, and genres are displayed and preserved likewise. Selected musical instruments are digitally recreated as 3D models playing their real sounds. Some of them will be available for the visitors to play in basic ways.\",\n \"Title: \\\"What is a good digital library?\\\" - A quality model for digital libraries\\nYear: 2007\\n\\nAbstract: In this article, we elaborate on the meaning of quality in digital libraries (DLs) by proposing a model that is deeply grounded in a formal framework for digital libraries: 5S (Streams, Structures, Spaces, Scenarios, and Societies). For each major DL concept in the framework we formally define a number of dimensions of quality and propose a set of numerical indicators for those quality dimensions. In particular, we consider key concepts of a minimal DL: catalog, collection, digital object, metadata specification, repository, and services. Regarding quality dimensions, we consider: accessibility, accuracy, completeness, composability, conformance, consistency, effectiveness, efficiency, extensibility, pertinence, preservability, relevance, reliability, reusability, significance, similarity, and timeliness. Regarding measurement, we consider characteristics like: response time (with regard to efficiency), cost of migration (with respect to preservability), and number of service failures (to assess reliability). For some key DL concepts, the (quality dimension, numerical indicator) pairs are illustrated through their application to a number of ''real-world'' digital libraries. We also discuss connections between the proposed dimensions of DL quality and an expanded version of a workshop's consensus view of the life cycle of information in digital libraries. Such connections can be used to determine when and where quality issues can be measured, assessed, and improved - as well as how possible quality problems can be prevented, detected, and eliminated.\",\n \"Title: VT at TREC-2003: The Web Track Report\\nYear: 2003\\n\\nAbstract: which uses Genetic Programming (GP) to discover the \\\"optimal\\\" ranking functions for various information needs. From Web Track 2002, the training, testing and validation data sets are constructed in the same manner as in Robust Track. Our ARRANGER engine works on those data sets and automatically searches for the \\\"best\\\" ranking functions. The best runs are selected for submission according to their performance on queries in Web track 2002.Our paper is organized as follows. Section 2 states our research objectives. Section 3 describes basic data processing steps. Section 4 summarizes the GP algorithm used in our system and detailed information about how we use GP to find ranking function. Section 5 shows the official submission results in comparison with the other TREC teams.\",\n \"Title: Interest-based user grouping model for collaborative filtering in digital libraries\\nYear: 2004\\n\\nAbstract: Research in recommender systems focuses on applications such as in online shopping malls and simple information systems. These systems consider user profile and item information obtained from data explicitly entered by users. – where it is possible to classify items involved and to make recommendations based on a direct mapping from user or user group to item or item group. However, in complex, dynamic, and professional information systems, such as Digital Libraries, additional capabilities are needed for recommender systems to support their distinctive features: large numbers of digital objects, dynamic updates, sparse rating data, biased rating data on specific items, and challenges in getting explicit rating data from users. In this paper, we present an interest-based user grouping model for a collaborative recommender system for Digital Libraries. Also, we present several user interfaces that obtain implicit user rating data. Our model uses a high performance document clustering algorithm, LINGO, to extract document topics and user interests from documents users access in a Digital Library. This model is better suited to Digital Libraries than traditional recommender systems because it focuses more on users than items and because it utilizes implicit rating data.\",\n \"Title: Interdisciplinary curriculum development for digital library education\\nYear: 2006\\n\\nAbstract: The Virginia Tech (VT) Department of Computer Science (CS) and the University of North Carolina at Chapel Hill (UNC-CH) School of Information and Library Science (LIS) are developing curricular materials for digital library (DL) education, appropriate for the CS and LIS communities. Educational modules will be designed, based on input from the project advisory board, Computing Curriculum 2001, the 5S framework, and workshop discussions. These modules will be evaluated, first through expert inspection and, second, through field testing. We are identifying and refining module definitions and scopes, collecting related resources, developing a module template, and creating example modules. These will be presented at the conference. The developed curriculum should contribute to producing well-balanced digital librarians who will graduate from CS or LIS programs.\",\n \"Title: Sharing the wealth: publishing electronic resources\\nYear: 2004\\n\\nAbstract: This poster describes the publication of educational resources in ACM's online Journal for Educational Resources in Computing (JERIC) and the US National Science Foundation's National STEM Digital Library (NSDL).\",\n \"Title: Automatic document metadata extraction using support vector machines\\nYear: 2003\\n\\nAbstract: Automatic metadata generation provides scalability and usability for digital libraries and their collections. Machine learning methods offer robust and adaptable automatic metadata extraction. We describe a support vector machine classification-based method for metadata extraction from header part of research papers and show that it outperforms other machine learning methods on the same task. The method first classifies each line of the header into one or more of 15 classes. An iterative convergence procedure is then used to improve the line classification by using the predicted class labels of its neighbor lines in the previous round. Further metadata extraction is done by seeking the best chunk boundaries of each line. We found that discovery and use of the structural patterns of the data and domain based word clustering can improve the metadata extraction performance. An appropriate feature normalization also greatly improves the classification performance. Our metadata extraction method was originally designed to improve the metadata extraction quality of the digital libraries Citeseer [S. Lawrence et al., (1999)] and EbizSearch [Y. Petinot et al., (2003)]. We believe it can be generalized to other digital libraries.\",\n \"Title: Demonstrating the use of a SenseCam in two domains\\nYear: 2006\\n\\nAbstract: MyLifeBits is both an application and a framework to manage a personal lifetime of memories. We will demonstrate the use of a small digital library that manages data from two Microsoft SenseCams, used by: 1) students in the Virginia-Maryland Regional College of Veterinary Medicine, and 2) students supported by our Assistive Technologies office.\",\n \"Title: From the WWW and minimal digital libraries, to powerful digital libraries: why and how\\nYear: 2005\\n\\nAbstract: Digital libraries have emerged since the early 1990s, distinguished in part by their emphasis on useful content, helpful organization, and a range of services that include at least indexing, searching, and browsing. In the 5S (Streams, Structures, Spaces, Scenarios, and Societies) formal model for digital libraries we precisely define key concepts and terms, so the field can move beyond the stage of continually explaining basic ideas and debating definitions. Thus, we define a minimal digital library in terms of clear definitions for repository, metadata catalog, services, and societies, which in turn build upon characterizations of digital object, collection, hypertext, etc.\",\n \"Title: Building Policy, Building Community: An Example from the US National Science, Technology, Engineering, and Mathematics Education Library (NSDL)\\nYear: 2002\\n\\nAbstract: Developing a major national resource such as the US National Science, Technology, Engineering, and Mathematics education Digital Library (NSDL) requires policy and technical expertise. Policy issues are as much a challenge as infrastructure in the construction of such a major digital library. This paper focuses on the policy making structures that have developed since 2000 when the US National Science Foundation began its funding for NSDL. The authors are the Vice Chair and Chair of the NSDL Policy Committee and report here on issues of voice, authority, and central issues for policy construction as these have emerged in the NSDL context.\",\n \"Title: Can We Get A Better Retrieval Function From Machine?\\nYear: 2004\\n\\nAbstract: The quality of an information retrieval system heavily depends on its retrieval function, which returns a similarity measurement between the query and each document in the collection. Documents are sorted according to their similarity values with the query and those with high rank are assumed to be relevant. Okapi BM25 and their variations are very popular retrieval functions and they seem to be the default retrieval function for the IR research community; and there are many other widely used and well studied functions, for example, Pivoted TFIDF and INQUERY. Most of these retrieval functions being used today are made based on probabilistic theories and they are adjusted in real world according to different contexts and information needs. In this paper, we propose the idea that a good retrieval function can be discovered by a pure machine learning approach, without using probabilistic theories and knowledge-based techniques. Two machine learning algorithms, Support Vector Machine (SVM) and Genetic Programming (GP) are used for retrieval function discovery, and GP is found to be a more effective approach. The retrieval functions discovered by GP might be hard for human interpretation, but their performance is superior to Okapi BM25, one of the most popular functions. The new retrieval function is combined with query expansion techniques and the retrieval performance is improved significantly. Based on our observations in the empirical study, the GP function is more reliable and effective than Okapi BM25 when query expansion techniques are used.\",\n \"Title: Users, user interfaces, and objects: Envision, a digital library\\nYear: 1993\\n\\nAbstract: Project Envision aims to build a ''user-centered database from the computer science literature,'' initially using the publications of the Association for Computing Machinery (ACM). Accordingly, we have interviewed potential users, as well as experts in library, information, and computer science-to understand their needs, to become aware of their perception of existing information systems, and to collect their recommendations. Design and formative usability evaluation of our interface have been based on those interviews, leading to innovative query formulation and search results screens that work well according to our usability testing. Our development of the Envision database, system software, and protocol for client-server communication builds upon work to identify and represent ''objects'' that will facilitate reuse and high-level communication of information from author to reader (user). All these efforts are leading not only to a usable prototype digital library but also to a set of nine principles for digital libraries, which we have tried to follow, covering issues of representation, architecture, and interfacing.\",\n \"Title: Using ACM DL paper metadata as an auxiliary source for building educational collections\\nYear: 2014\\n\\nAbstract: Some digital libraries harvest metadata records from multiple content providers to build their collections. However, the quality and quantity of such metadata records are limited by what is harvested. To ensure collection growth, and to expand the scope beyond just what can be harvested, additional content acquisition methods are needed. Accordingly, we discuss how the Ensemble project (a pathway effort in the NSDL) is broadening its collection with the help of machine learning. Since Ensemble aims to aid computing education, we make use of ACM Digital Library records as a resource to help with transfer learning. We have built classifiers that can identify if a potential additional resource is about computing education. We approached this as a cross-domain text classification problem and developed suitable methods for feature extraction and bootstrapping for classifier training. Our experiments on three datasets of computing education metadata records show our approach can enhance the quality and quantity of records being added to Ensemble.\",\n \"Title: Data mapping framework in a digital library with computational epidemiology datasets\\nYear: 2014\\n\\nAbstract: Computational epidemiology employs computer models and informatics tools to reason about the spatio-temporal spread of diseases. The diversity of models, data sources, data representations, and modalities that are collected, used, and modified motivate the development of a digital library (DL) framework to support computational epidemiology. The heterogeneous content includes metadata, text, tables, spreadsheets, experimental descriptions, and large result files. There is no accepted framework that allows unified access to such content. We propose a framework for a digital library system tailored to such datasets to support computational network epidemiology.\",\n \"Title: Intelligent digital libraries and tailored services\\nYear: 2014\\n\\nAbstract: next generation of intelligent information systems will emerge from recent digital library (DL) research. One aspect of this is based on intelligent technologies and applications in the DL area. Another aspect is based on advances in DL theory and related progress toward improved quality and integration. Together, these two aspects facilitate automation and empower users. Recent progress toward these goals, and the rich set of future possibilities in this regard, can be understood most clearly in the eScience context. Scientific research produces large amounts of complex, numeric content. A new class of DLs with supporting services for such content is vital to advancing scientific practice. Intelligent services also are needed to automate scientific workflows. Simulation environments are especially well suited for automation with digital libraries. The SimDL framework generates simulation-supporting DL instances. This framework includes a set of service implementations, a software toolkit, formal definitions of services and content, and processes for producing workflows of services and layers. Integrating such DL instances within a scientific research infrastructure leads to the automation of many routine tasks and to more intelligent services. This gives a glimpse of the future of more intelligent information systems.\",\n \"Title: Altmetrics for Country-Level Research Assessment.\\nYear: 2014\\n\\nAbstract: Changes are occurring in scholarly communication and the geography of science. Policymakersand research funding agencies are looking for ways to measure the comprehensive impact of research and benefit from the research experiences of other nations. Recently, altmetrics have been used to measure broader impact of research activities. In this paper, we study altmetrics based on the country-levelimpact andfind that altmetrics can support research evaluation for all countries studied. We compare altmetrics with several traditional metrics and findsignificant relationshipsbetween country-level altmetrics and the number of publications, citations, h-index, and gross domestic expenditure on research and development (GERD). We also find a significant yearly increase in the number of articles published between 2010 and 2014 that received altmetrics.\",\n \"Title: Media use during conflicts: information seeking gratifications & efficacy during 2012 Mexican elections\\nYear: 2014\\n\\nAbstract: Public access to accurate and reliable information is fundamental to democracy and democratic decision-making. In conditions of uncertainty and imperfect information, such as during political crises or controversial elections in emerging democracies, reliable information is often difficult to obtain. We investigated the uses and gratifications obtained from diverse information sources available to citizens during the months leading up to Presidential elections in Mexico in July 2012. Uses and gratifications theory states that information seeking is one of several primary needs or motivations for using different media. Reliability of information sources is key to gratification of this need. We conducted a survey about diverse information sources and their reliability with an opportunity sample of young adults at a public state university in Mexico. Our findings indicate that face-to-face and telephone communication with members of a respondent's social network, as well as social media and online news sites, were the most reliable sources of information about the elections. Television broadcasting, especially from government channels, was the least reliable. These results suggest that in conditions of relative uncertainty and imperfect information, social media and alternative (online) news sources about political events are essential to sustaining an informed public.\",\n \"Title: Recommendation based on Deduced Social Networks in an educational digital library\\nYear: 2014\\n\\nAbstract: Discovering useful resources can be difficult in digital libraries with large content collections. Many educational digital libraries (edu-DLs) host thousands of resources. One approach to avoiding information overload involves modeling user behavior. But this often depends on user feedback, along with the demographic information found in user account profiles, in order to model and predict user interests. However, edu-DLs often host collections with open public access, allowing users to navigate through the system without needing to provide identification. With few identifiable users, building models linked to user accounts provides insufficient data to recommend useful resources. Analyzing user activity on a per-session basis, to deduce a latent user network, can take place even without user profiles or prior use history. The resulting Deduced Social Network (DSN) can be used to improve DL services. An example of a DSN is a graph whose nodes are sessions and whose edges connect two sessions that view the same resource. In this paper we present a recommendation framework for edu-DLs that depends on deduced connections between users. Results show that a recommendation system built from DSN-dependent parameters can improve performance compared to when only text similarity between resources is used. Our approach can potentially improve recommendation for DL resources when implicit user activities (e.g., view, click, search) are abundant but explicit user activities (e.g., account creation, rating, comment) are unavailable.\",\n \"Title: The evolving genre of electronic theses and dissertations\\nYear: 1999\\n\\nAbstract: Electronic theses and dissertations (ETDs) are a unique genre that is emerging in part as a result of the work to build the Networked Digital Library of Theses and Dissertations (NDLTD). Virginia Tech began requiring ETDs January 1, 1997 and has since received over 1350. Quality has already improved and what one has learned is more broadly shared now due to the intense interest in ETDs. This is a flexible genre that will enhance digital libraries in part because over half contain color images or other multimedia, including audio, video, or VRML files. Due to free access, many have been downloaded thousands of times. As the NDLTD expands, tens of thousands of these will be created each year all over the globe and in the near future the NDLTD will broadly support multilingual and federated searching. This paper presents findings at Virginia Tech as a case study of shifting book-length works to electronic documents for the global digital library.\",\n \"Title: Reducing descriptor measurement error through bayesian estimation of fingerprint minutia location and direction\\nYear: 2012\\n\\nAbstract: Fingerprint-based recognition relies on the matching of features derived from the ridges and valleys of the friction ridge surface. When a large quantity of good-quality features are available, identification can be made with a high level of confidence. When portions of the fingerprint image are of lower quality, accuracy will suffer in the feature extraction and subsequent matching steps. This study is concerned with the correction of descriptor errors in minutiae (ridge endings and bifurcations), and with evaluation of the effect of feature accuracy on matching performance. The approach applies Bayesian filtering to refine minutia location and direction descriptors, using Sequential Monte Carlo approximation of a joint probability distribution near each minutia. The distribution approximates the location and orientation of the minutia, given measurements on local greyscale information, from which an expectation can be determined. Experimental results have been presented which demonstrate improvement of localisation accuracy with respect to ground truth data when using a well-known minutia extractor. These results are shown to be statistically significant, and to lead to improved matching performance. In addition, the authors were able to reduce the average minutia position error for a set of reference minutiae by 83% when using the proposed refinement method.\",\n \"Title: Robust feature extraction in fingerprint images using ridge model tracking\\nYear: 2012\\n\\nAbstract: This paper addresses the problem of feature extraction from low-quality regions in fingerprint images. Features such as minutiae are difficult to detect automatically when high levels of noise are present, as in wet, dry, or latent prints. The approach presented here is a novel application of Bayesian filtering to the problem of ridge tracing. A friction ridge is followed by recursively estimating posterior distributions representing the direction of each new step along the ridge. This approach benefits from previous state information when in an area that exhibits low ridge clarity, causing ridge-flow estimation to be unreliable. The new technique has been tested experimentally using a database of 880 grayscale fingerprint images with varying quality. The ability of the proposed method to detect features more reliably is confirmed by a reduction in Equal Error Rate of 2.1% and 2.5% over two traditional methods. In addition, the False Reject Rate was reduced by 11.1%, at a False Accept Rate of 1%, for a group of low-quality images. These results demonstrate a significant improvement, as compared with previous techniques, in the ability to process low-quality fingerprint images.\",\n \"Title: Temporal analysis of fingerprint impressions\\nYear: 2012\\n\\nAbstract: Fingerprint analysis has been performed on static images since the establishment of friction-ridge patterns as a reliable human trait for identification. The image of a fingerprint can vary considerably, however, as a result of such factors as skin elasticity and pressure on the imaging surface. With today's live-scan imaging devices, changes in appearance are notable as a finger presses against the scanning during acquisition. During the brief imaging period, fingerprint ridges stretch and compress, while some portions of the fingertip display varying levels of visibility and quality. Imaging systems select a single static image frame, thereby ignoring information that is absent from a particular image but present in others. This paper presents a novel approach that employs temporal analysis to a sequence of images captured during enrollment. Minutiae are extracted and tracked throughout the sequence to build a composite template that contains more genuine minutia than are found from simple static analysis. It was discovered, through temporal analysis, that 18.2% of minutiae changed type throughout a single impression sequence. The proposed method led to an increase in the number of minutiae detected by 25% and an improvement by 9.3% in the rank-1 identification rate of a set of partial prints, when using an imposter database of temporal composite templates over static templates.\",\n \"Title: Digital library initiative: a project for educators in Qatar\\nYear: 2013\\n\\nAbstract: This article presents the first phase of an exciting initiative in the Arabian Gulf State of Qatar that brings together four academic institutions working to develop a digital library infrastructure of people, services, software, hardware, and content related to Qatar. Building on prior work on curricular resources developed for the digital library field and extending them to support Arabic as well as English instruction, educators, librarians, and IT specialists are working with content experts, stakeholders, students, and researchers to identify and preserve Qatar oriented digital library collections and information systems.\",\n \"Title: Read between the lines: A Machine Learning Approach for Disambiguating the Geo-location of Tweets\\nYear: 2015\\n\\nAbstract: This paper describes a Machine Learning (ML) approach for extracting named entities and disambiguating the location of tweets based on those named entities and related content. We conducted experiments with tweets (e.g., about potholes), and found significant improvement in disambiguating tweet locations using a ML algorithm along with the Stanford NER. Adding state information predicted by our classifiers increases the possibility to find the state-level geo-location unambiguously by up to 80%.\",\n \"Title: Using Transactional Web Archives To Handle Server Errors\\nYear: 2015\\n\\nAbstract: We describe a web archiving application that handles server errors using the most recently archived representation of the requested web resource. The application is developed as an Apache module. It leverages the transactional web archiving tool SiteStory, which archives all previously accessed representations of web resources originating from a website. This application helps to improve the website's quality of service by temporarily masking server errors from the end user and gaining precious time for the system administrator to debug and recover from server failures. By providing pertinent support to website operations, we aim to reduce the resistance to transactional web archiving, which in turn may lead to a better coverage of web history.\",\n \"Title: Web Archiving and Digital Libraries (WADL)\\nYear: 2015\\n\\nAbstract: This workshop will explore integration of Web archiving and digital libraries, so the complete life cycle involved is covered: creation/authoring, uploading/publishing in the Web (2.0), (focused) crawling, indexing, exploration (searching, browsing), archiving (of events), etc. It will include particular coverage of current topics of interest, like: big data, mobile web archiving, and systems (e.g., Memento, SiteStory, Hadoop processing).\",\n \"Title: Big Data Text Summarization for Events: A Problem Based Learning Course\\nYear: 2015\\n\\nAbstract: Problem/project Based Learning (PBL) is a highly effective student-centered teaching method, where student teams learn by solving problems. This paper describes an instance of PBL applied to digital library education. We show the design, implementation, results, and partial evaluation of a Computational Linguistics course that provides students an opportunity to engage in active learning about adding value to digital libraries with large collections of text, i.e., one aspect of \\\\\\\"big data.\\\\\\\" Students are engaging in PBL with the semester long challenge of generating good English summaries of an event, given a large collection from our webpage archives. Six teams, each working with a different type of event, and applying three different summarization methods, learned how to generate good summaries; these have fair precision relative to the Wikipedia page that describes their event.\",\n \"Title: The Use and Impact of Social Media during the 2011 Tunisian Revolution.\\nYear: 2016\\n\\nAbstract: Citizen participation is a key factor in open government and a fundamental form of collective problem solving in democratic societies. Citizens need reliable information to support collective sense making and decision-making. During crises, such as political uprisings, reliable information sources are essential for citizens to stay informed and make sense of rapidly changing developments. In countries that exert control over media, citizens try to access alternative information sources, such as unfiltered Internet and social media. Using two rounds of online surveys with young adults in Tunisia, we examined the use of diverse media during the 2011 revolution. Our survey results show that higher perceptions of information reliability, along with the sharing of online information, lead to greater political information efficacy (PIE). Prior studies show higher PIE associated with greater democratic participation, which bodes well for collaborative decision-making in the nascent democracy in this North African state.\",\n \"Title: WADL 2016: Third International Workshop on Web Archiving and Digital Libraries.\\nYear: 2016\\n\\nAbstract: This workshop will explore integration of Web archiving and digital libraries, so the complete life cycle involved is covered: creation/authoring, uploading/publishing in the Web (2.0), (focused) crawling, indexing, exploration (searching, browsing), archiving (of events), etc. It will include particular coverage of current topics of interest, like: big data, mobile web archiving, and systems (e.g., Memento, SiteStory, Hadoop processing).\",\n \"Title: Big Data Processing of School Shooting Archives.\\nYear: 2016\\n\\nAbstract: Web archives about school shootings consist of webpages that may or may not be relevant to the events of interest. There are 3 main goals of this work; first is to clean the webpages, which involves getting rid of the stop words and non-relevant parts of a webpage. The second goal is to select just webpages relevant to the events of interest. The third goal is to upload the cleaned and relevant webpages to Apache Solr so that they are easily accessible. We show the details of all the steps required to achieve these goals. The results show that representative Web archives are noisy, with 2% - 40% relevant content. By cleaning the archives, we aid researchers to focus on relevant content for their analysis.\",\n \"Title: Automated arabic text classification with P-Stemmer, machine learning, and a tailored news article taxonomy.\\nYear: 2016\\n\\nAbstract: Arabic news articles in electronic collections are difficult to study. Browsing by category is rarely supported. Although helpful machine-learning methods have been applied successfully to similar situations for English news articles, limited research has been completed to yield suitable solutions for Arabic news. In connection with a Qatar National Research Fund QNRF-funded project to build digital library community and infrastructure in Qatar, we developed software for browsing a collection of about 237,000 Arabic news articles, which should be applicable to other Arabic news collections. We designed a simple taxonomy for Arabic news stories that is suitable for the needs of Qatar and other nations, is compatible with the subject codes of the International Press Telecommunications Council, and was enhanced with the aid of a librarian expert as well as five Arabic-speaking volunteers. We developed tailored stemming i.e., a new Arabic light stemmer called P-Stemmer and automatic classification methods the best being binary Support Vector Machines classifiers to work with the taxonomy. Using evaluation techniques commonly used in the information retrieval community, including 10-fold cross-validation and the Wilcoxon signed-rank test, we showed that our approach to stemming and classification is superior to state-of-the-art techniques.\",\n \"Title: Anatomy of Scholarly Information Behavior Patterns in the Wake of Social Media.\\nYear: 2016\\n\\nAbstract: As more scholarly content is being born digital or digitized, digital libraries are becoming increasingly vital to researchers leveraging scholarly big data for scientific discovery. Given the abundance of scholarly products-especially in environments created by the advent of social networking services-little is known about international scholarly information needs, information-seeking behavior, or information use. This paper aims to address these gaps by conducting an in-depth analysis of researchers in the United States and Qatar; learn about their research attitudes, practices, tactics, strategies, and expectations; and address the obstacles faced during research endeavors. Based on this analysis, the study identifies and describes new behavior patterns on the part of researchers as they engage in the information-seeking process. The analysis reveals that the use of academic social networks has remarkable effects on various scholarly activities. Further, this study identifies differences between students and faculty members in regard to their use of academic social networks, and it identifies differences between researchers according to discipline. The researchers who participated in the present study represent a range of disciplinary and cultural backgrounds. However, the study reports a number of similarities in terms of the researchersu0027 scholarly activities. Finally, the study illuminates some of the implications for the design of research platforms.\",\n \"Title: Media use during conflicts: Information seeking and political efficacy during the 2012 Mexican elections.\\nYear: 2016\\n\\nAbstract: Public access to accurate and reliable information is fundamental to democracy and democratic decision-making. In emerging democracies, during political crises or controversial elections, reliable information is often difficult to obtain. In authoritarian regimes, citizens' perceptions of information reliability are tightly linked to trust in government, and both are typically low. Open government policies help build trust that is essential during protests or contentious elections. Uses and gratifications (U&G) theory states that people use diverse media to try to satisfy their need for reliable information. Gratifying this need is tied to the larger concept of political information efficacy (PIE), i.e., the belief a person holds about him/herself as being politically informed and competent to participate in political thought and action. We investigated these inter-related concepts by administering a survey to an opportunity sample of young adults at a public state university in Mexico. We find that respondents perceived that information from face-to-face and telephone communication with members of their social network, as well as online sources were the most reliable. Information from offline sources, such as TV and newspapers, especially pro-government sources, were the least reliable. Further, the information factors of availability, reliability, influence and sharing had positive relationships with PIE. These results suggest that in conditions of uncertain political information, social networks and online information sources are essential to political information efficacy and democratic political participation.\",\n \"Title: Classifying Short Unstructured Data Using the Apache Spark Platform.\\nYear: 2017\\n\\nAbstract: People worldwide use Twitter to post updates about the events that concern them directly or indirectly. Study of these posts can help identify global events and trends of importance. Similarly, E-commerce applications organize their products in a way that can facilitate their management and satisfy the needs and expectations of their customers. However, classifying data such as tweets or product descriptions is still a challenge. These data are described by short texts, containing in their vocabulary abbreviations of sentences, emojis, hashtags, implicit codes, and other non-standard usage of written language. Consequently, traditional text classification techniques are not effective on these data. In this paper, we describe our use of the Spark platform to implement two classification strategies to process large data collections, where each datum is a short textual description. One of our solutions uses an associative classifier, while the other is based on a multiclass Logistic Regression classifier using Word2Vec as a feature selection and transformation technique. Our associative classifier captures the relationships among words that uniquely identify each class, and Word2Vec captures the semantic and syntactic context of the words. In our experimental evaluation, we compared our solutions, as well as Spark MLlib classifiers. We assessed effectiveness, efficiency, and memory requirements. The results indicate that our solutions are able to effectively classify the millions of data instances composed of thousands of distinct features and classes, found in our digital libraries.\",\n \"Title: Media Use By Young Tunisians During The 2011 Revolution Vs 2014 Elections\\nYear: 2017\\n\\nAbstract: Citizen participation is a key factor in open government and a fundamental form of collective problem solving in democratic societies. Citizens need reliable information to support collective sense making and decision-making. During crises, such as political uprisings and controversial elections, reliable information sources are essential for citizens to stay informed and make sense of rapidly changing developments. In countries that exert control over media, citizens try to access alternative information sources, such as unfiltered Internet and social media. Using two rounds of surveys with young, educated adults in Tunisia, we examined their use of diverse information sources during the 2011 revolution. We update these findings with a third survey round asking similar questions to young, educated Tunisian adults' about their use of diverse information sources during the 2014 presidential and parliamentary elections. Our results show there have been dramatic changes in the use and perceptions of the reliability of broadcast media as Tunisia builds a new government with more open participation and national communication media. The Internet and social media still play an important role in informing the Tunisian public, but new government and private sources are perceived as significantly more reliable than they were under the authoritarian regime overthrown by the 2011 revolution. Our election survey results show that higher perceptions of information reliability, along with the sharing of online information, lead to greater political information efficacy (PIE). Prior studies show higher PIE is associated with greater democratic participation. This finding bodes well for the nascent democracy emerging in this small North African state.\",\n \"Title: Focused crawler for events.\\nYear: 2018\\n\\nAbstract: There is need for an Integrated Event Focused Crawling system to collect Web data about key events. When a disaster or other significant event occurs, many users try to locate the most up-to-date information about that event. Yet, there is little systematic collecting and archiving anywhere of event information. We propose intelligent event focused crawling for automatic event tracking and archiving, ultimately leading to effective access. We developed an event model that can capture key event information, and incorporated that model into a focused crawling algorithm. For the focused crawler to leverage the event model in predicting webpage relevance, we developed a function that measures the similarity between two event representations. We then conducted two series of experiments to evaluate our system about two recent events: California shooting and Brussels attack. The first experiment series evaluated the effectiveness of our proposed event model representation when assessing the relevance of webpages. Our event model-based representation outperformed the baseline method (topic-only); it showed better results in precision, recall, and F1-score with an improvement of 20% in F1-score. The second experiment series evaluated the effectiveness of the event model-based focused crawler for collecting relevant webpages from the WWW. Our event model-based focused crawler outperformed the state-of-the-art baseline focused crawler (best-first); it showed better results in harvest ratio with an average improvement of 40%.\",\n \"Title: Web Archiving and Digital Libraries (WADL).\\nYear: 2018\\n\\nAbstract: The 2018 edition of the Workshop on Web Archiving and Digital Libraries (WADL) will explore the integration of Web archiving and digital libraries. The workshop aims at addressing aspects covering the entire life cycle of digital resources and will also explore areas such as community building and ethical questions around web archiving.\",\n \"Title: A Hybrid Model for Role-related User Classification on Twitter.\\nYear: 2018\\n\\nAbstract: To aid a variety of research studies, we propose TWIROLE, a hybrid model for role-related user classification on Twitter, which detects male-related, female-related, and brand-related (i.e., organization or institution) users. TWIROLE leverages features from tweet contents, user profiles, and profile images, and then applies our hybrid model to identify a useru0027s role. To evaluate it, we used two existing large datasets about Twitter users, and conducted both intra- and inter-comparison experiments. TWIROLE outperforms existing methods and obtains more balanced results over the several roles. We also confirm that user names and profile images are good indicators for this task. Our research extends prior work that does not consider brand-related users, and is an aid to future evaluation efforts relative to investigations that rely upon self-labeled datasets.\",\n \"Title: EpiK: A Knowledge Base for Epidemiological Modeling and Analytics of Infectious Diseases\\nYear: 2017\\n\\nAbstract: Computational epidemiology seeks to develop computational methods to study the distribution and determinants of health-related states or events (including disease), and the application of this study to the control of diseases and other health problems. Recent advances in computing and data sciences have led to the development of innovative modeling environments to support this important goal. The datasets used to drive the dynamic models as well as the data produced by these models presents unique challenges owing to their size, heterogeneity and diversity. These datasets form the basis of effective and easy to use decision support and analytical environments. As a result, it is important to develop scalable data management systems to store, manage and integrate these datasets. In this paper, we develop EpiK—a knowledge base that facilitates the development of decision support and analytical environments to support epidemic science. An important goal is to develop a framework that links the input as well as output datasets to facilitate effective spatio-temporal and social reasoning that is critical in planning and intervention analysis before and during an epidemic. The data management framework links modeling workflow data and its metadata using a controlled vocabulary. The metadata captures information about storage, the mapping between the linked model and the physical layout, and relationships to support services. EpiK is designed to support agent-based modeling and analytics frameworks—aggregate models can be seen as special cases and are thus supported. We use semantic web technologies to create a representation of the datasets that encapsulates both the location and the schema heterogeneity. The choice of RDF as a representation language is motivated by the diversity and growth of the datasets that need to be integrated. A query bank is developed—the queries capture a broad range of questions that can be posed and answered during a typical case study pertaining to disease outbreaks. The queries are constructed using SPARQL Protocol and RDF Query Language (SPARQL) over the EpiK. EpiK can hide schema and location heterogeneity while efficiently supporting queries that span the computational epidemiology modeling pipeline: from model construction to simulation output. We show that the performance of benchmark queries varies significantly with respect to the choice of hardware underlying the database and resource description framework (RDF) engine.\",\n \"Title: Visualizing user communities and usage trends of digital libraries based on user tracking information\\nYear: 2006\\n\\nAbstract: We describe VUDM, our Visual User-model Data Mining tool, and its application to data logged regarding interactions of 1,200 users of the Networked Digital Library of Theses and Dissertations (NDLTD). The goals of VUDM are to visualize social networks, patrons' distributions, and usage trends of NDLTD. The distinctive approach of this research is that we focus on analysis and visualization of users' implicit rating data, which was generated based on user tracking information, such as sending queries and browsing result sets – rather than focusing on explicit data obtained from a user survey, such as major, specialties, years of experience, and demographics. The VUDM interface uses spirals to portray virtual interest groups, positioned based on inter-group relationships. VUDM facilitates identifying trends related to changes in interest, as well as concept drift. A formative evaluation found that VUDM is perceived to be effective for five types of tasks. Future work will aim to improve the understandability and utility of VUDM.\",\n \"Title: Machine Learning Approach for Homepage Finding Task\\nYear: 2002\\n\\nAbstract: This paper describes new machine learning approaches to predict the correct homepage in response to a user's homepage finding query. This involves two phases. In the first phase, a decision tree is generated to predict whether a URL is a homepage URL or not. The decision tree then is used to filter out non-homepages from the web pages returned by a standard vector space information retrieval system. In the second phase, a logistic regression analysis is used to combine multiple sources of evidence based on the homepages remaining from the first step to predict which homepage is most relevant to a user's query. 100 queries are used to train the logistic regression model and another 145 testing queries are used to evaluate the model derived. Our results show that about 84% of the testing queries had the correct homepage returned within the top 10 pages. This shows that our machine learning approaches are effective since without any machine learning approaches, only 59% of the testing queries had their correct answers returned within the top 10 hits.\",\n \"Title: Anatomy of Scholarly Information Behavior Patterns in the Wake of Academic Social Media Platforms.\\nYear: 2019\\n\\nAbstract: As more scholarly content is born digital or converted to a digital format, digital libraries are becoming increasingly vital to researchers seeking to leverage scholarly big data for scientific discovery. Although scholarly products are available in abundance—especially in environments created by the advent of social networking services—little is known about international scholarly information needs, information-seeking behavior, or information use. The purpose of this paper is to address these gaps via an in-depth analysis of the information needs and information-seeking behavior of researchers, both students and faculty, at two universities, one in the USA and the other in Qatar. Based on this analysis, the study identifies and describes new behavior patterns on the part of researchers as they engage in the information-seeking process. The analysis reveals that the use of academic social networks has notable effects on various scholarly activities. Further, this study identifies differences between students and faculty members in regard to their use of academic social networks, and it identifies differences between researchers according to discipline. Although the researchers who participated in the present study represent a range of disciplinary and cultural backgrounds, the study reports a number of similarities in terms of the researchers’ scholarly activities.\",\n \"Title: ScanBank: A Benchmark Dataset for Figure Extraction from Scanned Electronic Theses and Dissertations\\nYear: 2021\\n\\nAbstract: We focus on electronic theses and dissertations (ETDs), aiming to improve access and expand their utility, since more than 6 million are publicly available, and they constitute an important corpus to aid research and education across disciplines. The corpus is growing as new born-digital documents are included, and since millions of older theses and dissertations have been converted to digital for...\",\n \"Title: Automatic Metadata Extraction Incorporating Visual Features from Scanned Electronic Theses and Dissertations\\nYear: 2021\\n\\nAbstract: Electronic Theses and Dissertations (ETDs) contain domain knowledge that can be used for many digital library tasks, such as analyzing citation networks and predicting research trends. Automatic metadata extraction is important to build scalable digital library search engines. Most existing methods are designed for born-digital documents such as GROBID, CERMINE, and ParsCit, so they often fail to ...\",\n \"Title: Teaching Natural Language Processing through Big Data Text Summarization with Problem-Based Learning\\nYear: 2020\\n\\nAbstract: Natural language processing (NLP) covers a large number of topics and tasks related to data and information management, leading to a complex and challenging teaching process. Meanwhile, problem-based learning is a teaching technique specifically designed to motivate students to learn efficiently, work collaboratively, and communicate effectively. With this aim, we developed a problem-based learning course for both undergraduate and graduate students to teach NLP. We provided student teams with big data sets, basic guidelines, cloud computing resources, and other aids to help different teams in summarizing two types of big collections: Web pages related to events, and electronic theses and dissertations (ETDs). Student teams then deployed different libraries, tools, methods, and algorithms to solve the task of big data text summarization. Summarization is an ideal problem to address learning NLP since it involves all levels of linguistics, as well as many of the tools and techniques used by NLP practitioners. The evaluation results showed that all teams generated coherent and readable summaries. Many summaries were of high quality and accurately described their corresponding events or ETD chapters, and the teams produced them along with NLP pipelines in a single semester. Further, both undergraduate and graduate students gave statistically significant positive feedback, relative to other courses in the Department of Computer Science. Accordingly, we encourage educators in the data and information management field to use our approach or similar methods in their teaching and hope that other researchers will also use our data sets and synergistic solutions to approach the new and challenging tasks we addressed.\",\n \"Title: Introduction to Digital Libraries\\nYear: 2021\\n\\nAbstract: This tutorial is a thorough and deep introduction to the Digital Libraries (DL) field, providing a firm foundation: covering key concepts and terminology, as well as services, systems, technologies, methods, standards, projects, issues, and practices. It introduces and builds upon a firm theoretical foundation (starting with the ‘5S’ set of intuitive aspects: Streams, Structures, Spaces, Scenarios...\",\n \"Title: Numerically Trained Ultrasound AI for Monitoring Tool Degradation\\nYear: 2022\\n\\nAbstract: Monitoring tool degradation during manufacturing can ensure product accuracy and reliability. However, due to variations in degradation conditions and complexity in signal analysis, effective and broadly applicable monitoring is still challenging to achieve. Herein, a novel monitoring method using ultrasound signals augmented with a numerically trained machine learning technique is reported to monitor the wear condition of friction stir welding and processing tools. Ultrasonic signals travel axially inside the tools, and even minor tool wear will change the time and amplitude of the reflected signal. An artificial intelligence (AI) algorithm is selected as a suitable referee to identify the small variations in the tool conditions based on the reflected ultrasound signals. To properly train the AI referee, a human-error-free data bank using numerical simulation is generated. The simulation models the experimental conditions with high fidelity and can provide comparable ultrasound signals. As a result, the trained AI model can recognize the tool wear from real experiments with subwavelength accuracy prediction of the worn amount on the tool pins.\",\n \"Title: How Should One Explore the Digital Library of the Future?\\nYear: 2021\\n\\nAbstract: This article partially addresses a challenge from Licklider in his 1965 book on “Libraries of the Future,” focusing on how to build extensible digital libraries that can dramatically expand the support of exploration. A new methodology connects the efforts of User eXperience researchers with those of subject matter experts (domain scientists, curators, researchers, and so on) and developers. This allows constructing a knowledge graph representing the relationships among goals, tasks, workflows, and services. A reasoner empowers authorized users to have their goals met with suitable workflows that are dynamically generated and executed. Student teams have applied the new methodology to support users interested in tweets, web pages, or electronic theses and dissertations, as well as those curating and experimenting with those collections. Exploration is thus broadened across content types and their elements, with an extensible set of services, to address an arbitrary set of stakeholder goals.\",\n \"Title: Web Archiving and Digital Libraries (WADL) 2022\\nYear: 2022\\n\\nAbstract: The 2022 edition of the Workshop on Web Archiving and Digital Libraries (WADL) will explore the integration of web archiving and digital libraries. The workshop aims at addressing aspects covering the entire life cycle of digital resources, including creation/authoring, uploading/publishing, crawling, indexing, exploration, and archiving. It will also explore areas such as archiving processes and tools for “non-traditional” resources such as social media, scholarly and government datasets, 3D objects, and digital online art. CCS CONCEPTS • Information systems $\\\\rightarrow$ Digital libraries and archives;\"\n]","isConversational":false},"profile_size":{"kind":"number","value":200,"string":"200"},"task":{"kind":"string","value":"longlamp_2"},"split_kind":{"kind":"string","value":"user_based"},"id":{"kind":"number","value":13382,"string":"13,382"}}},{"rowIdx":13383,"cells":{"question_id":{"kind":"string","value":"Jun Yan"},"question":{"kind":"string","value":"Generate an abstract for the title \"A multifunction transceiver RFIC for 802.11a/b/g WLAN and DVB-H applications\" using the following items: Wireless transceiver, WLAN, DVB-H, Super-heterodyne transceiver, Zero-IF receiver"},"answer":{"kind":"string","value":"We present a multifunction wireless transceiver RFIC for WLAN and DVB-H applications. The RFIC includes a super-heterodyne transceiver for IEEE 802.11 a/b/g WLAN applications and a zero-IF receiver for DVB-H application. The WLAN and DVB-H transceiver share the down-conversion mixers, the baseband VGAs, filters, and the PLL synthesizer, resulting in a small silicon area of 20 mm2. Using a 3.3 V supply, the power consumption of the WLAN transceiver and the DVB-H receiver are 462 mW and 396 mW, respectively."},"correct_answer":{"kind":"string","value":"We present a multifunction wireless transceiver RFIC for WLAN and DVB-H applications. The RFIC includes a super-heterodyne transceiver for IEEE 802.11 a/b/g WLAN applications and a zero-IF receiver for DVB-H application. The WLAN and DVB-H transceiver share the down-conversion mixers, the baseband VGAs, filters, and the PLL synthesizer, resulting in a small silicon area of 20 mm2. Using a 3.3 V supply, the power consumption of the WLAN transceiver and the DVB-H receiver are 462 mW and 396 mW, respectively."},"documents":{"kind":"list like","value":["Title: A Path-oriented Approach to Generating Executable Test Sequences for Extended Finite State Machines\nYear: 2012\n\nAbstract: The Extended Finite State Machine (EFSM) is a commonly used model for specifying software systems. A test sequence for an EFSM is a sequence composed of values of input variables, which can make the EFSM “execute” along a complete path from entry to exit. Traditional test sequence generation methods for EFSM almost imitate those FSM-based approaches and focus on states identification. Most of them impose significant restrictions on the EFSM. This paper proposes a path-oriented approach to generating test cases for EFSM and presents a tool for test data generation. The experiments show that our tool can generate executable test sequences for EFSM models of software systems automatically in acceptable time.","Title: The Fuzzy-AI Modeling for Optimization of Long-Term Metro Vehicle Repair\nYear: 2009\n\nAbstract: In this paper, the “Fuzzy-AI model” is applied for investment decision of optimum repair of multiple metro vehicles. The model solves this highly uncertain and sophisticated problem both based on its fuzzy analysis and reasoning of existing distressed metro vehicles. The VDSI (vehicle distress state indicator) is used in finding the optimum investment management of repair, which is a fuzzy synthesis of quantized indicator for the distressed vehicle. An optimization of long-term vehicle repair investment planning is suggested.","Title: Evaluating instruction cache vulnerability to transient errors\nYear: 2007\n\nAbstract: Recent research shows that microprocessors are increasingly susceptible to transient errors. In order to protect microprocessors cost-effectively, the first step is to accurately understand the impact of transient errors on the system reliability. While many research efforts have been focused on studying the vulnerability of data caches and other on-chip hardware components, instruction caches have received less attention. However, instructions are read every cycle, any undetected or uncorrected soft errors in instructions can lead to erroneous computation, wrong control flow or system crash.This paper studies the instruction cache vulnerability by considering both the raw SRAM rate and the cache vulnerability factor. Based on the concept of cache vulnerability factor, we also investigate the impact of different cache configuration parameters on the reliability of instruction caches. We find that on average 67.5% of instruction cache soft errors can be masked by the I-cache itself without impacting other system components. While quantifying the instruction cache vulnerability itself does not solve the reliability problem of instruction cache against transient errors, we believe this work can provide useful insights for designers to develop cost-effective solutions to protect I-caches and to optimally balance the reliability of instruction caches with other system goals, such as cost, performance and energy.","Title: ServiceTrust: Supporting Reputation-Oriented Service Selection\nYear: 2009\n\nAbstract: Service transactions, although attached with service level agreements, may still fail due to various reasons, intentionally or accidentally, in the open and volatile service-oriented environment. In service selection, consumers often need to estimate the trustworthiness of the provider with limited prior experience and knowledge about them. Moreover, the service-oriented environment exposes consumers to unique threats including malicious reputation manipulation and quality-of-service (QoS) abuse. This paper presents ServiceTrust --- a novel trust management approach to support reputation-oriented service selection by quantifying and comparing the trustworthiness of providers based on their historic performance over service transactions. ServiceTrust combines a consumer's and other consumers' personal trust to estimate the provider's trust value. Our experimental results demonstrate that ServiceTrust can significantly increase the success rate of service transactions and is effective in resisting malicious reputation manipulation and QoS abuse.","Title: Mining Adaptive Ratio Rules from Distributed Data Sources\nYear: 2006\n\nAbstract: Different from traditional association-rule mining, a new paradigm called Ratio Rule (RR) was proposed recently. Ratio rules are aimed at capturing the quantitative association knowledge, We extend this framework to mining ratio rules from distributed and dynamic data sources. This is a novel and challenging problem. The traditional techniques used for ratio rule mining is an eigen-system analysis which can often fall victim to noise. This has limited the application of ratio rule mining greatly. The distributed data sources impose additional constraints for the mining procedure to be robust in the presence of noise, because it is difficult to clean all the data sources in real time in real-world tasks. In addition, the traditional batch methods for ratio rule mining cannot cope with dynamic data. In this paper, we propose an integrated method to mining ratio rules from distributed and changing data sources, by first mining the ratio rules from each data source separately through a novel robust and adaptive one-pass algorithm (which is called Robust and Adaptive Ratio Rule (RARR)), and then integrating the rules of each data source in a simple probabilistic model. In this way, we can acquire the global rules from all the local information sources adaptively. We show that the RARR technique can converge to a fixed point and is robust as well. Moreover, the integration of rules is efficient and effective. Both theoretical analysis and experiments illustrate that the performance of RARR and the proposed information integration procedure is satisfactory for the purpose of discovering latent associations in distributed dynamic data source.","